SysCAD Documentation - User contributions [en]

Shell and Tube Heat Exchanger 2

2026-02-13T19:30:14Z

John.McFeaters: /* Method: Condensing */

[[Category:Models]]
{{Navigation|[[Models]]|[[Models#Energy Transfer Models|Energy Transfer Models]]}}
{{Flash Cond HX header table|currentpage=4}}
----
{{TOC}}
== General Description ==

The Shell and Tube Heat Exchanger 2 is used to transfer energy from one stream to another. '''It is primarily used to transfer latent heat from a condensing vapour stream, currently only steam, to a liquor stream.''' The liquor stream may contain liquids and solids. The unit may also be used for sensible heat exchange between two fluids without any phase changes.

There are several operational modes combination for the Shell and Tube Heat Exchanger 2. See [[#Selecting Operating Methods for Shell and Tube 2|Selecting Operating Methods for Shell and Tube 2]].

If the heat exchanger is inserted as part of a Flash Train, see [[Flash Train]] for a description of the theory and variables. This documentation will only discuss the variables for a 'standalone' heat exchanger.

An Environmental Heat Loss may be included in the unit under some operating modes, see the above table. This allows the user to specify a heat loss, or gain, between the unit and the environment.

A key difference with the [[Shell and Tube Heat Exchanger]] is that a Reaction Block ([[RB]]) can be included on the tube side. Please do be aware that only Reactions are recognised in this unit. Any Source, Sink or HX in the reaction file will be '''IGNORED'''.

=== Diagram ===

[[Image:ShellnTube2.gif]]

The diagram shows the default drawing of the shell and tube heat exchanger 2, with the required connecting streams. The user may also connect a vent stream to the unit. This is optional and allows non-condensable and excess steam to be removed from the unit.

The physical location of the connections is not important; the user may connect the streams to any position on the drawing. When the user inserts a heat exchanger into a flowsheet, he may choose a different drawing from a pull down menu.

== Inputs and Outputs ==

{| border="1" cellpadding="5" cellspacing="0"
|-
| valign="top" rowspan="2" | '''Label''' || valign="top" rowspan="2" | '''Required<br>Optional''' || valign="top" rowspan="2" | '''Input<br>Output ''' || colspan="2" | '''Number of Connections''' || valign="top" rowspan="2" | '''Description'''
|-
| '''Min''' || '''Max'''
|-
| |Tube_In ||1 Required ||In || 1 || 10 || The liquid or slurry feed to the unit. Reactions are allowed in the Tube side.
|-
| |Tube_Out ||Required ||Out ||1 || 1 || The liquid or slurry outlet.
|-
| |Shell_In ||1 Required ||In || 1 || 10 || The steam inlet in condensing mode. <br>When using "sensible HX mode with EnironHX", this should be the hot in.
|-
| |Shell_Out ||Required ||Out || 1 || 1 || The condensate out in condensing mode. <br>When using "sensible HX mode with EnironHX", this should be the hot out.
|-
| |Vent ||Optional ||Out ||0 || 1 ||Optional shell side vent for non-condensable and excess steam.
|}

Note: Incoming streams to the same connection label are perfectly mixed before any unit operations are performed.

== Behaviour when Model is OFF ==

If the user disables the unit, by un-ticking the ''On'' tick box, then the following actions occur:
* All streams connected to the 'Shell' inlet will flow out of the 'Shell' outlet with no temperature or phase change;
* All streams connected to the 'Tube' inlet will flow out of the 'Tube' outlet with no temperature or phase change;
* Any sub-models, such as Reaction Block, will not occur;
* No energy exchange will occur.

So basically, the unit will be 'bypassed' without the user having to change any connections.

== Model Theory ==

=== General Theory ===

{{General Heat Exchanger Theory}}

=== Method: Sensible HX ===

* The Sensible HX operating mode allows user to enter a value for environment heat loss. To make sure he heat loss is applied correctly to the hot side, the hot stream must be connected to the Shell side.
* '''Bypassing and Temperature control''' ({{Available139}})
:While in sensible heat model, user can set a portion of the shell or tube feed to bypass the heat transfer calculations. User can also select the bypass control to adjust the bypass fraction to meet the outlet shell/tube temperature requirements.
:The bypass flow can be visualised as:
:[[File:ST2 Bypass.png]]

=== Method: Condensing ===
* Steam must be connected to the Shell side.
* '''Autoclave Option'''
*:Selecting the '''Autoclave''' option: Calculates MTD based on difference between condensing temperature and primary (tube) outlet temperature. This simulates a fully mixed autoclave with internal steam heating. The advantage of this over the present [[Tank]] heat exchange element is that it can be act as part of a [[Flash Train]].
*:The Autoclave option is available for Condensing and Live Steam operations. Note that in Live Steam operation, area is ignored, all available steam will be condensed to the the limit where the incoming primary stream is heated to the steam condensing temperature. Steam flow should be controlled externally in this case.

* '''Including Reactions'''
*:Selecting the '''Use.RMTD''' option: (Reactive Mean Temperature Difference). If there are significant reactions along a heat exchanger section, then the temperature profile may be different to that used in calculation LMTD (Log Mean Temperature Difference). The effective mean temperature difference is also different, though in most cases only by a small percentage. Though for example, if very large amounts of heat were generated by reactions, the heat transfer direction could even reverse.
*:The RMTD option implements an alternative calculation of MTD, accounting for the reaction heat. In some cases (the example just given) this may give numerical errors. Use the LMTD in that case. If the LMTD and RMTD are dramatically different, this is an indication that the reactions have a significant influence on overall heat transfer.
*:'''NOTE:''' The Shell and Tube 2 unit will '''IGNORE''' any Source, Sink or Heat Exchange in the Reaction file. Only Reactions will be recognised.

* '''General Demand'''
*:If the Condensing Method is '''Demand (UA)''', then the model will condense (and hence demand) sufficient steam at the feed saturation conditions to satisfy the LMTD equation.

*'''Add in Tube Out Temperature Constraint'''
*:Selecting the Condensing Method to be '''Demand (UA & Tube T)''' adds in one extra constraint - the tube outlet temperature. This means the process must have one more variable to change to balance the flowsheet, and this variable is the steam pressure.
*:'''NB''' The Demand (UA & Tube T) method does ''not'' allow vent, reactions or environmental heat transfer. Note that switching from Demand (UA) method to Demand (UA & Tube T) method and then switching back again to Demand (UA) may lose reaction and heat transfer data.
::{|
|-
|Internally, the working of the model can be visualised as having a control valve to adjust the steam inlet pressure to achieve the target tube outlet temperature as shown below:

[[File:ST2 UA and tubeT.png]]
|
The steam line pressure drop is shown in the model as Shell.dP and the Tube outlet Temperature set point is entered as RequiredTubeT.

This method will work out the amount of steam needed based on the UA of the heater, and the pressure drop required will be determined by the tube out temperature. When using this method, user must be certain of the heater configuration and temperature out requirements, as a solution may not be possible if for example the vapour temperature is too low.

* Note the difference with the Demand (UA) method - in that case there is no control on the steam flow, and hence the tube outlet temperature is unconstrained.
* The Demand methods work with multiple steam feeds. In this case, there must be a ''single''' supply connected to a demand source, the others receiving fixed flows. If the fixed flows are inadequate to meet the demand requirement, the demand flow will be adjusted to make up the difference. If the fixed flows are '''greater''' than needed to meet demand, then excess flow will be vented or passed to the condensate outlet.
* Multiple feeds at ''different'' pressures are physically unrealistic and care should be taken in this case. All the feeds will be combined at the demand feed pressure - with the saturation temperature being that of the demand supply. This may give misleading results if there is excess flow from the fixed supplies and they are at different pressures to the demand supply.
|}

* '''Configuration Limits'''
*:To avoid temperature cross over issues:
*# Slurry out Temperature is limited to be <= Condensate out temperature.
*# When using the Demand (UA & TubeT) method, the Shell Pressure drop will be limited by the condensate out temperature, as this temperature cannot be lower than the user defined Tube.TemperatureReqd.
*# UA is currently limited to 10,000 kW/K. If a larger value is needed, use multiple exchangers in series or parallel as appropriate - this will give a better overall representation of large heat transfer models.
*# The Shell and Tube 2 unit will IGNORE any Source, Sink or HX in the reaction file - e.g. if a reaction file with a source is loaded, the source will be ignored and any reactions which have the source species in them will not occur.
*# Vent Mass flow limit allows the user to limit the maximum flow as a percentage of the steam entering the HX. This allows at least some steam to be used for condensing.
*# Tube side flow limit: if tube side flow is below this limit, the HX is considered to be inoperative.
*# Heat loss limit allows the user to define the maximum heat loss as a percent of condenser duty.

=== Method: Evaporating ===

{{Available139}}

The '''cold''' fluid is connected to the '''Shell''' and the hot fluid to the Tube side. The Hot fluid will provide the energy for the evaporation of the cold fluid.

The amount of evaporation could be limited by feed conditions and/or heater configurations (such as HTC and area). Possible outcomes are:
*No Evaporation: The Shell fluid is heated to a temperature below its saturation temperature. (If energy available is less than energy required for evaporation)
*Partial Evaporation: The flash species is partially vaporised at its saturation temperature. (If energy available is less than energy required for Complete evaporation)
*Complete Evaporation: The flash species is completely vaporised and subsequently superheated. (If energy available is greater than energy required for Complete evaporation)
*Forced Evaporate All: If the "EvaporateAll" tickbox is ticked, The flash species is completely vaporised while ignoring the area provided, the shell out temperature will be at the saturation temperature.
**Note that this mode could return an energy balance error where if energy required for Complete evaporation is greater than energy available.

*'''Assumptions'''
*#The Heat Transfer Coefficient is constant; in particular it is not a function of the vapour fraction in the fluid being vaporised.
*# Heat transfer in the Heat Exchanger is defined by the [[#General Theory|LMTD equation]] regardless of the phase composition of the fluid being vaporised.
*# There is no phase change in the hot fluid which supplies energy for the vaporisation.
*# If the fluid is partially vaporised, its final temperature is the saturation temperature of the remaining liquid .
*# The Heat Exchanger will not operate as a Condenser (notwithstanding that this may be physically possible).

===Selecting Operating Methods for Shell and Tube 2===
{| class="wikitable"
|-
! || Method || Condensing Method || Demand Connection || Autoclave || Reactions || EnvironHX || Vent ||Description
|-
|1 || '''Sensible HX''' || || || N/A || allowed || allowed || allowed || Used for simple heat exchange operations between the two sides, with no phase change. The hot side can be connected to either tube or shell. Flow demand network is allowed to pass through on the tube side only.
|-
|2 || rowspan=7|'''Condensing''' || No Demand Calc || || allowed || allowed || allowed || allowed || Steam supply to be specified by the user, unit will condense all the steam to water, Maximum Tube out temperature is limited to be the same as steam feed temperature. If excess amount is supplied, unit will return a warning for possible energy imbalance.
|-
|3 || rowspan=3|Demand (UA) || None (manual) || allowed || allowed || allowed || allowed || Steam supply to be specified by the user, unit will condense steam to water based on the Heater UA (HTC and Area) supplied. Maximum Tube out temperature is limited to be the same as steam feed temperature. If excess amount is supplied, unit will return a warning.
With this configuration, the steam supply must be correctly specified by the user, normally via a General Controller or Set Tag Controller. This is easily implemented as the steam flow required is calculated and displayed as tag VapourFlow.Rqd.
|-
|4 || FlashTrain || allowed || allowed || allowed || allowed || Steam supply to be connected to Flash Tank Vapour outlet, the unit will demand steam from the flash tank based the Heater UA (HTC and Area) supplied. All steam is condensed to water.
|-
|5 || General Demand || allowed || allowed || allowed || allowed ||Steam supply is connected directed or indirectly to a Feeder (with Demand.On selected), unit will demand and condense steam to water based on the Heater UA (HTC and Area) supplied. If excess amount is supplied (minimum in feeder too high), unit will return a warning. '''The Demand (UA) models are essentially uncontrolled, the tube outlet temperature being determined by the area and heat transfer coefficient'''
|-
|6 || rowspan=3|Demand (UA& TubeT) || None (manual) || N/A || N/A || N/A || N/A || Steam supply to be specified by the user, unit will condense all the supplied steam to water. The user also defines the required Tube out temperature, this sets the maximum tube out temperature. The variable in this configuration is the steam feed pressure, if too much steam is supplied, the unit will attempt to drop the pressure of the steam to balance all the specified constraints. If a balance is not found, warnings are given. The minimum shell out temperature (achieved by pressure drop) is limited to the tube out temperature. This method also assumes the user know the exact size of the heater.
With this configuration, the steam supply must be correctly specified by the user, normally via a General Controller or Set Tag Controller. This is easily implemented as the steam flow required is calculated and displayed as tag VapourFlow.Rqd.
|-
|7 || FlashTrain || N/A || N/A || N/A || N/A || Steam supply to be connected to Flash Tank Vapour outlet, the unit will demand steam from the flash tank based the Heater UA and tube outlet temperature supplied. All steam is condensed to water. If the heater area is too big to give the required tube out temperature, the steam pressure is dropped to attempt to achieve a balance. The minimum shell out temperature (achieved by pressure drop) is limited to the tube out temperature. The maximum tube out temperature is limited by the user specified tube out temperature.
|-
|8 || General Demand || N/A || N/A || N/A || N/A || Steam supply is connected directed or indirectly to a Feeder (with Demand.On selected), unit will demand and condense steam to water based on the Heater UA and Tube out Temperature supplied. If excess amount is supplied (minimum in feeder too high), unit will return a warning. All steam is condensed to water. If the heater area is too big to give the required tube out temperature, the steam pressure is dropped to attempt to achieve a balance. The minimum shell out temperature (achieved by pressure drop) is limited to the tube out temperature. The maximum tube out temperature is limited by the user specified tube out temperature. '''Compared to the Demand (UA) configuration, this mode controls (by dropping) the steam pressure to achieve the desired outlet temperature'''
|-
|9 || '''Evaporating''' || || || N/A || N/A || N/A || N/A || {{Available139}} Shell side stream can be evaporated. Hot stream expected to be on tube side.
|-
|}

== Data Sections ==

The default access window consists of several sections:

# '''[[#Shell and Tube Heat Exchanger 2 Page|ShellTube2]]''' tab - This first tab contains general information relating to the unit.
# '''[[Material Flow Section|QTubeIn]]''' - Optional tab, only visible if ''ShowQTubeIn'' is enabled. This page shows the properties of the mixed stream as the feed to the Tube side.
# '''[[Material Flow Section|QShellIn]]''' - Optional tab, only visible if ''ShowQShellIn'' is enabled. This page shows the properties of the mixed stream as the feed to the Shell side.
# '''[[VLE]]''' - Only visible if the unit is in either ''Condensing'' or ''Evaporating'' mode.
# '''[[RB]]''' - Optional tab, only visible if the Reactions are enabled. Please note that the Shell and Tube 2 unit will IGNORE any Source, Sink or HX in the reaction file.
# '''[[#ShellSide Tab|ShellSide]]''' - Optional tab, only visible if the user selects ''Tube Detail'' for the layout.
# '''[[#TubeSide Tab|TubeSide]]''' - Optional tab, only visible if the user selects ''Tube Detail'' for the layout.
# '''[[Common Data Sections#Common Data on Info Tab Page|Info]]''' tab - Contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
# '''[[Links Table|Links]]''' tab, contains a summary table for all the input and output streams.
# '''[[Audit]]''' tab - Contains summary information required for Mass and Energy balance. See [[Model Examples]] for enthalpy calculation Examples.

===Shell and Tube Heat Exchanger 2 Page===
'''Unit Type: ShellTube2''' - The first tab page in the access window will have this name.

{| border="1" cellpadding="5" cellspacing="0" align="center"
| '''Tag (Long/Short)'''||'''Input / Calc'''||'''Description/Calculated Variables / Options'''
|-
{{Common Data on First Tab Page}}
|-
| colspan="3" font style="background: #ebebeb" |

=== Requirements ===
|-
| On|| Tick Box || Switches the Heat Exchanger on/off
|-
| rowspan=3|Method|| Sensible HX || This will allow sensible heat exchange between two streams. No phase change will take place automatically. Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| Condensing || This is used to condense the steam. Steam must be connected to Shell In. Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| Evaporating || {{Available139}} This is used to evaporate a stream, usually water. The stream to be evaporated must be connected to Shell In while the hotter stream must be connected to Tube In.
|-
| colspan="3" font style="background: #ebebeb" | ''(Bypass functionality is only {{Available139||y}}.)''
|-
| rowspan=3|Bypass.Option<br>(Only visible if ''Method'' is set to '''Sensible HX''')|| No Bypass || Full Tube and shell flows will be used for heat transfer calculations.
|-
| Bypass Shell Feed || user can specify a portion of the shell feed to bypass the heat transfer calculations, this is equivalent to adding a split to the shell feed, the bypassed amount will be added to the shell out stream.
|-
| Bypass Tube Feed || user can specify a portion of the tube feed to bypass the heat transfer calculations, this is equivalent to adding a split to the tube feed, the bypassed amount will be added to the tube out stream.
|-
| rowspan=3|Bypass.Control<br>(Only visible if ''Bypass.Option'' is set to '''Bypass Shell Feed''' or '''Bypass Tube Feed''')|| Fixed Fraction || user can specify a fixed portion of the shell/tube feed to bypass the heat transfer calculations.
|-
| Shell Outlet T || the portion of the shell/tube feed to bypass the heat transfer calculations is adjusted to meet the user defined shell outlet temperature.
|-
| Tube Outlet T || the portion of the shell/tube feed to bypass the heat transfer calculations is adjusted to meet the user defined tube outlet temperature.
|-
| Bypass.FracReqd || Input || Only displayed if ''Bypass.Control'' = '''Fixed Fraction'''.
|-
| Bypass.T_Reqd || Input || Only displayed if ''Bypass.Control'' is set to '''Shell Outlet T''' or '''Tube Outlet T'''.
|-
| Bypass.FracMax || Input || Only displayed if ''Bypass.Option'' is set to '''Bypass Shell Feed''' or '''Bypass Tube Feed'''.
|-
| rowspan=3|CondensingMethod <br>(Only visible if ''Method'' is set to '''Condensing''')|| No Demand Calc|| The Steam addition is manually specified by the user, all steam supplied (less vent) will be condensed. Duty will be based on Tot.Cond.Duty (total condensing duty). NOTE: Duty may not equal to TheoreticalDuty (calculated from HX UA and LMTD) as steam input is manual. Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| Demand (UA) || The steam demand is calculated base on the user specified Heater HTC and Area (UA). Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| Demand (UA&TubeT)|| The steam demand is calculated base on the user specified Heater HTC, Area and the tube outlet temperature. Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| rowspan=3|DemandConnection<br>(Only visible if ''CondensingMethod'' is set to one of the '''Demand''' methods)|| None (Manual) || Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| FlashTrain || The steam supply comes from a Flash Tank and the ''Flash Tank - Heater'' is in a Flash train mode. Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| GeneralDemand || The steam supply comes from (directly or indirectly) a Feeder with Demand.on selected. Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| Tube.TemperatureReqd / Tube.T_Reqd || Input || Only visible if the ''CondensingMethod'' is set to '''Demand (UA & Tube T)'''. User specified Tube out Temperature. This is also the maximum Temperature for the Tube outlet stream.
|-
| Reactions|| List box || Switches the Reactions on/off. Reactions occur on the tube side only and the Shell and Tube 2 unit IGNORES any Source, Sink or HX in the reaction file.
|-
| ShellSide.On|| Tick Box || Only visible if ''CondensingMethod'' is set to '''No demand calc''' or '''Demand (UA)'''. Use this to effectively switch the Heat Exchanger on/off while solving.
|-
| Autoclave || Tick Box || Only visible if ''Method'' = '''Condensing'''. If this is enabled the unit will use temperature difference rather than LMTD in heater calculations. Calculates MTD based on difference between condensing temperature and primary (tube) outlet temperature. This simulates a fully mixed autoclave with internal steam heating.
|-
| Use.RMTD || Tick Box || Only visible if Reactions are 'On' and ''CondensingMethod'' = '''Demand (UA)'''. This enables an alternative calculation of MTD, accounting for the reaction heat. See theory above.
|-
| valign="top" | IgnoreSteamFlow || valign="top" | Tick Box || This is only available if ''CondensingMethod'' = '''Demand (UA)'''. Adjust steam feed rate to match duty and report excess or low flow conditions. When the flash train model has converged correctly, the steam flow rate will be matched and an error is not reported.<br>'''Note:''' If this option is enabled and
# The steam flow to the Heat Exchanger is LESS than required, extra steam will be added to the Heat Exchanger, i.e. Condensate Flow > Steam to HX; or
# The steam flow to the Heat Exchanger is MORE than required, the extra steam will be 'thrown away' from the Heat Exchanger, i.e. Condensate Flow < Steam to HX.
|-
| Flow.Damping || Input || This is only available if ''CondensingMethod'' = '''Demand (UA)'''. In solving macro models, there may be situations when the solver overshoots and fails to converge. This is because the demand from the model is interacting with supply from Flash Tanks. If the unit model steam flow and pressure seems to be oscillating about, then put in a value of 0.8 for the flow damping. This will stabilize the oscillations and allow the model to converge. It will slow the overall convergence rate if used when unnecessary, so only turn this on (change the default value of 0.0) if flash trains are not converging.
|-
| EnvironHX || Tick Box || Switches the environmental heat exchanger sub model on/off, used for additional heat losses. This is NOT available if ''CondensingMethod'' = '''Demand (UA & TubeT)'''.
|-
| rowspan=3|Env.Model|| colspan="2" font style="background: #ebebeb" | Only available if EnvironHX has been selected. For EnvironHX to perform correctly, the HOT stream must be connected to the Shell side.
|-
| None|| No environmental heat loss.
|-
| FixedHeatFlow || Fixed Environmental heat loss for the unit operation.
|-
| Env.HeatFlowReqd || Input/Calc || Only shown if EnvironHX has been enabled. The amount of heat lost to the environment.
|-
| Env.MaxLossFrac || Input/Calc || Only shown if EnvironHX has been enabled. The maximum fraction of heat lost to the environment as a percent of HX duty.
|-
| rowspan=2|Layout|| '''Overall''' || User specifies the overall heater area and HTC
|-
| '''TubeDetail'''|| User can specify the tube side in more detail. Refer to the Tubeside Tab for details.
|-
| HTC || Input/Calc || If the '''Overall''' method is selected then this field allows the user to specify the heat transfer coefficient. <br> If the '''TubeDetail''' method is selected then this field shows the calculated heat transfer coefficient (the HTC is specified on the ShellSide/TubeSide tabs).
|-
| Area || Input/Calc || If the '''Overall''' method is selected then this field allows the user to specify the heat transfer area. <br> If the '''TubeDetail''' method is selected then this field shows the calculated heat transfer area (based on user specified information on the TubeSide tab). 
|-
| LMTDFact || Input || User specified LMTD factor
|-
| VentMassFlowReqd|| Input || Only available if ''CondensingMethod'' = '''No demand calc''' or '''Demand (UA)'''. User specified amount of steam to be vented (This could be limited based on steam available)
|-
| Vent.MassFracOfFeed|| Input || Only available if ''CondensingMethod'' = '''No demand calc''' or '''Demand (UA)'''. User specified maximum fraction of steam to be vented based on feed steam to the HX.
|-
| Tube.LowQmLimit|| Input || User specified minimum tube side flow, if flow is lower than the limit, then the HX is considered to be inoperative.
|-
| EvaporateAll || Tick Box || {{Available139}} Only displayed if ''Method'' = '''Evaporating'''. All of the VLE species in the shell side stream will be evaporated, i.e. evaporation will not be limited by area.
|-
| colspan="3" font style="background: #ebebeb" | '''Options'''
|-
| ShowQTubeIn || Tick Box || QTubeIn and associated tab pages (e.g. Sp) will become visible, showing the properties of the combined Tube feed stream. See [[Material Flow Section]]. This will be prior to any sub-model actions (e.g. Reactions).
|-
| ShowQShellIn || Tick Box || QShellIn and associated tab pages (e.g. Sp) will become visible, showing the properties of the combined Shell feed stream. See [[Material Flow Section]]. This will be prior to any sub-model actions.
|-
| ShowQTubeOut || Tick Box || QTubeOut and associated tab pages (e.g. Sp) will become visible, showing the properties of the combined Tube side outlet stream. See [[Material Flow Section]].
|-
| ShowQShellOut || Tick Box || QShellOut and associated tab pages (e.g. Sp) will become visible, showing the properties of the combined Shell side outlet stream. See [[Material Flow Section]].
|-
| TrackShellFlowWhenOff || Tick Box || Only used when model is Off. Gives a warning condition when the model is off and there is shell side feed. For the Condensing ''Method'' with FlashTrain ''DemandConnection'' then this warning is always given when the model is off and there is shell side feed flow. {{Available139|32033}}
|-
| colspan="3" font style="background: #ebebeb" | '''Calculation Modes''' (Only shown if Tube Detail is selected for Layout)
|-
| rowspan=2|TSdPCalc|| Fixed || User specified pressure drop for the tubeside.
|-
| Full ||
|-
| TS.RqdPressureDrop|| Input || Allows user defined pressure drop for the tube side. Only shown if ''TSdpCalc'' is set to ''Fixed''.
|-
| TS.Scaling|| Tick Box || Allows scaling for the Tubeside (will display extra fields on TubeSide Tab page).
|-
| TS.Blockage|| Tick Box || Allows simulation of blockage on the Tubeside (will display extra fields on TubeSide Tab page).
|-
| colspan="3" font style="background: #ebebeb" |

=== Results ===
|-
| Operating|| font style="background: #ebebeb"|On/Off || Returns the operating status of the HX. If the HX is switched off, ShellSide is switched off or tube side flow < Tube.LowQmLimit, this will be shown 0 (inoperative), otherwise, it will be shown as 1 (operating).
|-
| U*A / UA|| font style="background: #ebebeb"|Calc || The heat exchanger UA. Note that if the product of ''HTC'' and ''Area'' is below a minimum limit, the value shown here and used in the model calculations is a non-zero low limit.
|-
| LMTD|| font style="background: #ebebeb"|Calc || The calculated log mean temperature difference. If the heat exchanger has Superheated Steam condensing on the shell side, then the LMTD method will produce small inaccuracies, please see [[Log Mean Temperature Difference (LMTD) Discussion]].
|-
| RMTD|| font style="background: #ebebeb"|Calc || It is only calculated and used if the "Use.RMTD" option is selected, otherwise RMTD is set to equal LMTD. The Reactive Mean Temperature Difference - this method of calculating the log mean temperature difference includes the temperature change due to the reactions.
|-
| TheoreticalDuty / TheorDuty|| font style="background: #ebebeb"|Calc || The theoretical duty of the heat exchanger.
|-
| Duty|| font style="background: #ebebeb"|Calc || The calculated Heater Duty
|-
| DutyDiff|| font style="background: #ebebeb"|Calc || The difference between theoretical and calculated Heater Duty.
|-
| DutyDiff.RelErr|| font style="background: #ebebeb"|Calc || The difference between theoretical and calculated Heater Duty as percent (relative error).
|-
| Reaction.Ht || font style="background: #ebebeb"| Calc || This is only visible if Reactions are enabled. This field displays the energy from the reactions referenced to RB feed temperature and standard pressure.
|-
| Reaction.Ht@0 || font style="background: #ebebeb"| Calc || This is only visible if Reactions are enabled. This field displays the energy from the reactions referenced to 0°C and standard pressure.
|-
| TheoreticalArea / TheorArea|| font style="background: #ebebeb"|Calc || The calculated heat exchanger area required to handle the duty.
|-
| DutyDirection || font style="background: #ebebeb"|Calc || Only visible if ''Method'' = '''Sensible HX'''. The direction of heat flow (from hot to cold), 'Shell to Tubes' or 'Tubes to Shell'.
|-
| Tot.Cond.Duty || font style="background: #ebebeb"|Calc || Only visible if ''Method'' = '''Condensing'''. The total duty from condensing steam.
|-
| HeatFlow || font style="background: #ebebeb"|Calc || The heat loss due to environmental heat exchange.
|-
|FlashComponent / FlashComp ||font style="background: #ebebeb" |Display|| Displays the flashing component used for the VLE calculation. This can be selected from the VLE tab.
|-
|Evap.ExtraHeatFlow|| font style="background: #ebebeb"|Calc || {{Available139}} Only displayed when the following conditions are met: ''Method'' = ''Evaporating'', the ''Evaporate All'' option is selected, and after solving, the unit requires additional energy to fully evaporate the shell contents.
|-
| Evap.FinalState || font style="background: #ebebeb"|Calc || {{Available139}} Only displayed when ''Method'' = '''Evaporating''' and after project solve. The description of the solved solution.
<syntaxhighlight>(0) Forced Evaporate All
(1) Shell Inlet T > Tube Inlet T
(2) Can't Boil - No Area Restriction
(3) Can't Boil - Area Restriction
(5) Partial vapourisation at Sat T - No Area Limit
(6) Partial vapourisation at Sat T - Area Limit
(10) Maximum Superheat - No Area Limitation
(11) Maximum Superheat Limited by Heat Exchanger
(12) Crossover
(13) Partial vapourisation at Sat T - No Area Limit
(15) Superheat - Shell Limit
(16) Superheat - Area(S) Limit</syntaxhighlight>
|-
| Evap.SolveCase || font style="background: #ebebeb"|Calc || {{Available139}} Only displayed when ''Method'' = '''Evaporating''' and after project solve. The solved condition, described by case number, the matching description is displayed in the "Evap.FinalState".
|-
| Evap.TargetDuty || font style="background: #ebebeb"|Calc || {{Available139}} Only displayed when ''Method'' = '''Evaporating''' and after project solve.
|-
| Evap.RequiredArea || font style="background: #ebebeb"|Calc || {{Available139}} Only displayed when ''Method'' = '''Evaporating''' and after project solve. The Minimum area required for complete evaporation of VLE species in Shell side.
|-
| colspan="3" font style="background: #ebebeb" |

=== Tube Side ===
|-
| TemperatureIn / Ti || font style="background: #ebebeb"|Calc || Tube in temperature.
|-
| TemperatureOut / To|| font style="background: #ebebeb"|Calc || Tube out temperature. This is the temperature of non-bypassed flow.
|-
| DeltaT / dT|| font style="background: #ebebeb"|Calc || Temperature change on tube side (To - Ti).
|-
| PressureIn / Pi || font style="background: #ebebeb"|Calc || Tube in pressure.
|-
| PressureOut / Po|| font style="background: #ebebeb"|Calc || Tube out pressure.
|-
| PressChange / dP || font style="background: #ebebeb"|Calc || Pressure drop in the tube side (Po - Pi).
|-
| MassFlow / Qm|| font style="background: #ebebeb"|Calc || The mass flowrate going through the tube side. This is the mass flow that is '''NOT''' bypassed.
|-
| colspan="3" font style="background: #ebebeb" |

=== Shell Side ===
|-
| TemperatureIn / Ti|| font style="background: #ebebeb"|Calc || Shell in temperature.
|-
| TemperatureOut / To|| font style="background: #ebebeb"|Calc || Shell out temperature. This the temperature of non-bypassed flow.
|-
| DeltaT / dT|| font style="background: #ebebeb"|Calc || Temperature change on shell side (To - Ti).
|-
| PressureIn / Pi || font style="background: #ebebeb"|Calc || Shell in pressure.
|-
| PressureOut / Po|| font style="background: #ebebeb"|Calc || Shell out pressure.
|-
| PressChange / dP|| font style="background: #ebebeb"|Calc || Pressure drop in the shell side (Po - Pi).
|-
| MassFlow / Qm|| font style="background: #ebebeb"|Calc || The mass flowrate going through the shell side, less any amount vented. This is the mass flow that is '''NOT''' bypassed.
|-
| Shell.DmdQm|| font style="background: #ebebeb"|Calc || Only visible if part of a flash train. This is the amount of steam needed from connected flash train units (flash tank or steam feeders), not including any fixed amount of steam input.
|-
| Shell.FxdQm|| font style="background: #ebebeb"|Calc || Only visible if part of a flash train. This is the amount of steam added in manually, thus not from connected flash train units. Note this portion of steam addition is not included in the pressure calculation of the flash train group.
|-
| colspan="3" font style="background: #ebebeb" |
=== Overall Unit - Including Bypass ===
|-
| colspan="3" font style="background: #ebebeb" | ''(The following set of results are only shown if ''Bypass.Option'' is set to '''Bypass Shell Feed''' or '''Bypass Tube Feed'''. {{Available139}})''
|-
| Bypass.Fraction / Frac || font style="background: #ebebeb"|Calc || The bypassed fraction.
|-
| Bypass.MassFlow / Qm|| font style="background: #ebebeb"|Calc || The bypassed flow.
|-
| colspan="3" font style="background: #ebebeb" |'''Tube Side'''
|-
| TemperatureIn / Ti || font style="background: #ebebeb"|Calc || Tube in temperature.
|-
| TemperatureOut / To|| font style="background: #ebebeb"|Calc || Tube out temperature. This is the final temperature of the combined stream, including bypassed flow.
|-
| DeltaT / dT|| font style="background: #ebebeb"|Calc || Temperature change on tube side (To - Ti).
|-
| PressureIn / Pi || font style="background: #ebebeb"|Calc || Tube in pressure.
|-
| PressureOut / Po|| font style="background: #ebebeb"|Calc || Tube out pressure.
|-
| PressChange / dP || font style="background: #ebebeb"|Calc || Pressure drop in the tube side (Po - Pi).
|-
| MassFlow / Qm|| font style="background: #ebebeb"|Calc || The total mass flowrate on the tube side, '''including''' bypassed flow.
|-
| colspan="3" font style="background: #ebebeb" |'''Shell Side'''
|-
| TemperatureIn / Ti || font style="background: #ebebeb"|Calc || Shell in temperature.
|-
| TemperatureOut / To|| font style="background: #ebebeb"|Calc || Shell out temperature. This is the final temperature of the combined stream, including bypassed flow.
|-
| DeltaT / dT|| font style="background: #ebebeb"|Calc || Temperature change on shell side (To - Ti).
|-
| PressureIn / Pi || font style="background: #ebebeb"|Calc || Shell in pressure.
|-
| PressureOut / Po|| font style="background: #ebebeb"|Calc || Shell out pressure.
|-
| PressChange / dP || font style="background: #ebebeb"|Calc || Pressure drop in the shell side (Po - Pi).
|-
| MassFlow / Qm|| font style="background: #ebebeb"|Calc || The total mass flowrate on the shell side, '''including''' bypassed flow.
|-
| colspan="3" font style="background: #ebebeb" |
''' Vent''' (only visible if Vent stream is connected)
|-
| Vent.MassFlow / Qm|| font style="background: #ebebeb"|Calc || The mass flowrate going through the vent.
|-
| Vent.NonCond.Qm|| font style="background: #ebebeb"|Calc || The mass flowrate of non-condensables going through the vent.
|-
| colspan="3" font style="background: #ebebeb" |

=== Calculated Vapour Flow Demand ===
|-
| VapourFlow.Reqd|| font style="background: #ebebeb"|Calc || The calculated steam flow to meet the Heater requirements. When the heater is not in GeneralDemand or FlashTrain mode, use a General controller or SetTag Controller to get this value to set the steam flowrate.
|-
| VapourFlow.Actual|| font style="background: #ebebeb"|Calc || The actual steam flow to heater.
|-
| VapourFlow.Error|| font style="background: #ebebeb"|Calc || The mass imbalance in the unit operation. This will warn the user if the amount of steam supplied exceeds the heater requirements. Most common when the heater is not in demand mode and the steam flow has not been set up to auto adjust.
|-
| VapourFlow.RelErr|| font style="background: #ebebeb"|Calc || The relative mass imbalance error in the unit operation. This will warn the user if the amount of steam supplied exceeds the heater requirements.
|-
| Condensate.Demand|| font style="background: #ebebeb"|Calc || This is only shown if the CondensingMethod selected is Demand (UA). This is the amount of steam which is passed back to the flash train.
|-
| LastMassFlow|| font style="background: #ebebeb"|Calc || This is only shown if the CondensingMethod selected is Demand (UA). This is the last mass flowrate through the shell side. This is used in combination with Flow.Damping.
|-
| colspan="3" font style="background: #ebebeb" |

=== Flash Train Macro Model ===
Note: Extra fields are visible if the unit is part of a Flash Train. These fields are described below. Please refer to '''[[ Flash Train]]'''.
{{Flash Train Macro Data Table Section | Cond = Yes | Evap = No | Name1=FT_001 | Name2=ST_001 | UnitOp=Shell and Tube Heat Exchanger }}
|}

=== ShellSide Tab ===

This tab page is only shown if "Method=Condensing" and "Layout = Tube Detail".

{| border="1" cellpadding="5" cellspacing="0"
| width=120|'''Tag (Long/Short)'''||width=120|'''Input / Calc'''||width=1000|'''Description/Calculated Variables / Options'''
|-
| colspan="3" font style="background: #ebebeb" |'''Requirements'''
|-
| ShellSideHTC|| Input || Shell side heat transfer coefficient.
|}

=== TubeSide Tab ===

This tab page is only shown if "Layout = Tube Detail".

{| border="1" cellpadding="5" cellspacing="0"
| width=120|'''Tag (Long/Short)'''||width=120|'''Input / Calc'''||width=1000|'''Description/Calculated Variables / Options'''
|-
| colspan="3" font style="background: #ebebeb" |'''Requirements'''
|-
| Tube.conductivity|| Input || Tube side conductivity.
|-
| NumberTubes|| Input || User specified number of tubes used to calculate the Heater area.
|-
| TubeLength|| Input || User specified tube length used to calculate the Heater area.
|-
| TubeID|| Input || User specified inner diameter used to calculate the Heater area.
|-
| TubeOD|| Input || User specified outside diameter used to calculate the Heater area.
|-
| TubePlateThickness || Input || User specified tube plate thickness.
|-
| TubeSidePasses|| Input || Tube side passes, used to configure the blockage.
|-
| SpecifyViscosity || Tick Box|| This allows the user to specify a viscosity, used in the dP calculation.
|-
| UserViscosity || Input ||Only visible if the 'SpecifyViscosity' box is ticked. User defined viscosity.
|-
| TubeRoughness || Input || Tube Roughness, used in the dP calculation.
|-
| EntranceCc|| Input || The contraction coefficient for entrance losses.
|-
| ExitCc|| Input || The contraction coefficient for exit losses.
|-
| colspan="3" font style="background: #ebebeb" |'''HeatTransfer'''
|-
| TubeSideHTC|| Input || Tube side heat transfer coefficient.
|-
| Scale.Thick|| Input || Tubeside scale thickness. Visible with TS.Scaling selected.
|-
| Scale.Cond|| Input || Tubeside scale conductivity. Visible with TS.Scaling selected.
|-
|-
| colspan="5" font style="background: #ebebeb" |'''''Pass Tube Blockage'''''
|-
|Pass || font style="background: #ebebeb" |Pass_Number|| This is defined by the TubeSidePasses Value
|-
|Blockage || Input || The blockage in the pass, as percentage, maximum value is 99%
|-
| dPIO || font style="background: #ebebeb"|Calc ||
|-
|dPFr ||font style="background: #ebebeb"|Calc ||
|-
| dPTot ||font style="background: #ebebeb"|Calc ||
|-
| colspan="3" font style="background: #ebebeb" |'''Results'''
|-
| AreaReduction || font style="background: #ebebeb"|Calc || Only visible if the TS.blockage is used. This is the heat transfer area reduction caused by the blockage(s).
|-
| CalcArea || font style="background: #ebebeb"|Calc || The calculated heat exchange area.
|-
| TS.HTC || font style="background: #ebebeb"|Calc || Tube side HTC used.
|-
| TS.Vel || font style="background: #ebebeb"|Calc || Tube side velocity. Not visible if the TS.blockage is used.
|-
| TS.G || font style="background: #ebebeb"|Calc || The average mass flow velocity.
|-
| colspan="3" font style="background: #ebebeb" |'''In'''
|-
| TSin.Re|| font style="background: #ebebeb"|Calc || Tube side inlet Reynolds number
|-
| TSin.ft|| font style="background: #ebebeb"|Calc ||
|-
| TSin.dPdL|| font style="background: #ebebeb"|Calc ||
|-
| colspan="3" font style="background: #ebebeb" |'''Out'''
|-
| TSout.Re|| font style="background: #ebebeb"|Calc || Tube side outlet Reynolds number
|-
| TSout.ft|| font style="background: #ebebeb"|Calc ||
|-
| TSout.dPdL|| font style="background: #ebebeb"|Calc ||
|-
| colspan="3" font style="background: #ebebeb" |'''Total'''
|-
| TS.dPIO|| font style="background: #ebebeb"|Calc || Tube side pressure drop
|-
| TS.Calc_dP|| font style="background: #ebebeb"|Calc || The calculated tube side pressure drop
|}

=== Vent Stream ===

The user can specify an amount of steam to be lost from the shell without contacting the tubes, QmVentRqd. If a vent stream is connected the steam will be sent to this link. If the user has not connected a vent stream, this amount of steam will be shown in the tab 'Last Vent' (however, this is not recommended - if the user expects steam to vent then it is good practice to connect a vent stream to the unit) If the amount of steam sent to the unit is less than the user defined amount, QmVentRqd, the unit will flag the user that the specified conditions cannot be met.

Any non-incondensable gases in the steam will also be vented via the vent stream.

If excess steam is sent to the shell and tube heat exchanger, i.e. it is not all condensed in the unit, then the excess steam will report to the condensate line. This is true even if the user has connected a vent stream to the unit.

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=HeatExchange | DllSubGroup=Heat Transfer | UnitOp=Shell & Tube(2) | Group=Energy Transfer}}

== Hints and Comments ==

=== Operation Mode selection and Shortcomings ===

Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]

The flow demand network can be passed through the tube side of the heat exchanger.

=== General Configuration Hints ===
#The user MUST use Steam Condensing mode if the unit is required to condense the steam entering the shell.
#For Steam Condensing operation modes, the hot side MUST be connected to the Shell_In and the cold side MUST be connected to the Tube_In.
#Ensure that the HTC and Area are correct. If these variables are not configured, the heat exchanger will not operate as expected.
#The Environmental Heat Transfer (EnvironHX) occurs between the shell side fluid and the environment prior to heat exchange. If heat loss is enabled, then less heat will be available for heat transfer to the tube side.
#*In the case of flash train configuration, more steam will be required to satisfy the heater requirements.
#*For Sensible HX operation modes with user specified environment heat loss, the hot side MUST be connected to the Shell_In and the cold side MUST be connected to the Tube_In.
#If the heat exchanger is disabled, but the EHX is enabled, then the shell side stream will still transfer heat to the environment.
#If the unit has a bad mass and energy balance this could be caused by an excess of steam flowing to the unit.
#When using the Demand (UA & TubeT) method:
:*user will be warned if the HTC / Area or Steam Supply Temperature is too low to achieve the required temperature. If this warning appears, please adjust the heater configuration accordingly.
:*If the heater area is too big, the steam pressure will be dropped to attempt to satisfy the tube out temperature requirement. The steam Pressure change is limited by the Tube Out Temperature, thus, the condensate temperature cannot be lower than the Tube out Temperature.
:*If the steam supply is in excess, there will be a mass imbalance in the model, user will be given a warning, to prevent this, make sure the steam supply is auto adjusted via General controller / Set Tag Controller or put into demand mode (where possible).

=== Hints on using a Shell & Tube Heat Exchanger ===

a) Some of the intended uses of the heat exchanger model in ProBal mode are:

*To help size the heat exchanger area with known flowrates - In this case, we will specify the Steam flowrate, Steam properties such as T and P, HTC and have a "controller" calculate the HX area to achieve a certain cooling water outlet temperature (T<sub>o</sub>).

*To find out the steam requirements based on known heat exchanger size and steam properties. - In this case, we will input HX HTC & area, as well as the steam properties (T & P), then through a controller, work out the steam flowrate to achieve a certain cooling water outlet temperature T<sub>o</sub>.

*As part of the [[Flash Train]]. NOTE that when the HX is set up as part of a flash train, in fully condensing mode, it behaves differently in that you can not "set" any flows to the HX, the flow is governed by the size of the HX. As part of the flash train, the fully condensing HX will calculate the steam amount required and "demand" this of the preceding units.

b) In ProBal mode, if you are using a "stand-alone" heater, you must control the steam flow by setting the Steam flowrate - typically a ''Qm_Rqd'' through a controller or set the Feeder to Demand mode. Changing the pressure or temperature of the Steam in the feed would not change the steam flowrate without the use of some form of control logic.

c) The Demand modes obviate the need to use a flow controller and will help convergence of complex flow sheets since the outlet temperature from the exchanger is fixed. In general, you should not never to use flow controllers in a heat exchager model.

d) A pressure drop can be specified in the pipes between flash tanks and/or heat exchangers. This may be required for a flash train arrangement. The CondensingSteam - Demand (UA & TubeT) has built in pressure drops for the Steam in, this might be a good model to use if the user wants to find out what the pressure drops are using some known temperature profile.

=== Comments on Heat Balance around the Heater ===

The HX LMTD will contain a small error when the HX is in '''Fully condensing''' mode with superheated steam as its feed. Please see [[Log Mean Temperature Difference (LMTD) Discussion]] for further information.

=== Heat of Reaction ===

Having reaction heat in a heat exchanger adds a lot of complication to the overall analysis. For example if the cold stream generates enough heat through reactions, it may end up ''hotter'' than the hot stream, and hence the direction of heat transfer will reverse!

Even without these pathological situations, the reaction heat can significantly change the thermal profile in the exchanger (i.e. the temperatures on the hot and cold sides), and hence has a significant influence on the effective mean temperature difference and total overall heat transfer.

SysCAD determines the reaction heat by evaluating a '''Reaction Block''' which can be added to the model. If the reaction heat is negligible compared to the overall heat transfer, then it is sufficient to use the LMTD formulation: the calculated reaction heat is just added or removed from the total heat transfer to the tube side.

If the reaction heat is of the same order of magnitude as the heat transfer, then the RMTD option can give a better estimate of heat transfer.

==== RMTD Analysis ====

The ''Reactive Mean Temperature Difference'' is calculated by assuming that reaction heat is ''uniformly'' generated within the fluid. (If the reaction rate and heat of reaction is strongly temperature dependent, then the exchanger could be divided into a number of units in series, with different reaction rates and reaction heat production)

This distributed heat production or absorbtion modifies the overall thermal transfer. The theoretical development of the model assumes that heat transfer is always from the hot to the cold side: if the overall reaction heat is such as to reverse this, then the model fails and will fall back on a LMTD calculation with a warning. In this case you should look closely at the model to see if the reaction heat being generated is realistic.

Shell and Tube Heat Exchanger 2

2026-02-13T19:07:06Z

John.McFeaters: /* Method: Condensing */

[[Category:Models]]
{{Navigation|[[Models]]|[[Models#Energy Transfer Models|Energy Transfer Models]]}}
{{Flash Cond HX header table|currentpage=4}}
----
{{TOC}}
== General Description ==

The Shell and Tube Heat Exchanger 2 is used to transfer energy from one stream to another. '''It is primarily used to transfer latent heat from a condensing vapour stream, currently only steam, to a liquor stream.''' The liquor stream may contain liquids and solids. The unit may also be used for sensible heat exchange between two fluids without any phase changes.

There are several operational modes combination for the Shell and Tube Heat Exchanger 2. See [[#Selecting Operating Methods for Shell and Tube 2|Selecting Operating Methods for Shell and Tube 2]].

If the heat exchanger is inserted as part of a Flash Train, see [[Flash Train]] for a description of the theory and variables. This documentation will only discuss the variables for a 'standalone' heat exchanger.

An Environmental Heat Loss may be included in the unit under some operating modes, see the above table. This allows the user to specify a heat loss, or gain, between the unit and the environment.

A key difference with the [[Shell and Tube Heat Exchanger]] is that a Reaction Block ([[RB]]) can be included on the tube side. Please do be aware that only Reactions are recognised in this unit. Any Source, Sink or HX in the reaction file will be '''IGNORED'''.

=== Diagram ===

[[Image:ShellnTube2.gif]]

The diagram shows the default drawing of the shell and tube heat exchanger 2, with the required connecting streams. The user may also connect a vent stream to the unit. This is optional and allows non-condensable and excess steam to be removed from the unit.

The physical location of the connections is not important; the user may connect the streams to any position on the drawing. When the user inserts a heat exchanger into a flowsheet, he may choose a different drawing from a pull down menu.

== Inputs and Outputs ==

{| border="1" cellpadding="5" cellspacing="0"
|-
| valign="top" rowspan="2" | '''Label''' || valign="top" rowspan="2" | '''Required<br>Optional''' || valign="top" rowspan="2" | '''Input<br>Output ''' || colspan="2" | '''Number of Connections''' || valign="top" rowspan="2" | '''Description'''
|-
| '''Min''' || '''Max'''
|-
| |Tube_In ||1 Required ||In || 1 || 10 || The liquid or slurry feed to the unit. Reactions are allowed in the Tube side.
|-
| |Tube_Out ||Required ||Out ||1 || 1 || The liquid or slurry outlet.
|-
| |Shell_In ||1 Required ||In || 1 || 10 || The steam inlet in condensing mode. <br>When using "sensible HX mode with EnironHX", this should be the hot in.
|-
| |Shell_Out ||Required ||Out || 1 || 1 || The condensate out in condensing mode. <br>When using "sensible HX mode with EnironHX", this should be the hot out.
|-
| |Vent ||Optional ||Out ||0 || 1 ||Optional shell side vent for non-condensable and excess steam.
|}

Note: Incoming streams to the same connection label are perfectly mixed before any unit operations are performed.

== Behaviour when Model is OFF ==

If the user disables the unit, by un-ticking the ''On'' tick box, then the following actions occur:
* All streams connected to the 'Shell' inlet will flow out of the 'Shell' outlet with no temperature or phase change;
* All streams connected to the 'Tube' inlet will flow out of the 'Tube' outlet with no temperature or phase change;
* Any sub-models, such as Reaction Block, will not occur;
* No energy exchange will occur.

So basically, the unit will be 'bypassed' without the user having to change any connections.

== Model Theory ==

=== General Theory ===

{{General Heat Exchanger Theory}}

=== Method: Sensible HX ===

* The Sensible HX operating mode allows user to enter a value for environment heat loss. To make sure he heat loss is applied correctly to the hot side, the hot stream must be connected to the Shell side.
* '''Bypassing and Temperature control''' ({{Available139}})
:While in sensible heat model, user can set a portion of the shell or tube feed to bypass the heat transfer calculations. User can also select the bypass control to adjust the bypass fraction to meet the outlet shell/tube temperature requirements.
:The bypass flow can be visualised as:
:[[File:ST2 Bypass.png]]

=== Method: Condensing ===
* Steam must be connected to the Shell side.
* '''Autoclave Option'''
*:Selecting the '''Autoclave''' option: Calculates MTD based on difference between condensing temperature and primary (tube) outlet temperature. This simulates a fully mixed autoclave with internal steam heating. The advantage of this over the present [[Tank]] heat exchange element is that it can be act as part of a [[Flash Train]].
*:The Autoclave option is available for Condensing and Live Steam operations. Note that in Live Steam operation, area is ignored, all available steam will be condensed to the the limit where the incoming primary stream is heated to the steam condensing temperature. Steam flow should be controlled externally in this case.

* '''Including Reactions'''
*:Selecting the '''Use.RMTD''' option: (Reactive Mean Temperature Difference). If there are significant reactions along a heat exchanger section, then the temperature profile may be different to that used in calculation LMTD (Log Mean Temperature Difference). The effective mean temperature difference is also different, though in most cases only by a small percentage. Though for example, if very large amounts of heat were generated by reactions, the heat transfer direction could even reverse.
*:The RMTD option implements an alternative calculation of MTD, accounting for the reaction heat. In some cases (the example just given) this may give numerical errors. Use the LMTD in that case. If the LMTD and RMTD are dramatically different, this is an indication that the reactions have a significant influence on overall heat transfer.
*:'''NOTE:''' The Shell and Tube 2 unit will '''IGNORE''' any Source, Sink or Heat Exchange in the Reaction file. Only Reactions will be recognised.

* '''General Demand'''
*:If the Condensing Method is '''Demand (UA)''', then the model will condense (and hence demand) sufficient steam at the feed saturation conditions to satisfy the LMTD equation.

*'''Add in Tube Out Temperature Constraint'''
*:Selecting the Condensing Method to be '''Demand (UA & Tube T)''' adds in one extra constraint - the tube outlet temperature. This means the process must have one more variable to change to balance the flowsheet, and this variable is the steam pressure.
*:'''NB''' The Demand (UA & Tube T) method does ''not'' allow reactions or environmental heat transfer.
::{|
|-
|Internally, the working of the model can be visualised as having a control valve to adjust the steam inlet pressure to achieve the target tube outlet temperature as shown below:

[[File:ST2 UA and tubeT.png]]
|
The steam line pressure drop is shown in the model as Shell.dP and the Tube outlet Temperature set point is entered as RequiredTubeT.

This method will work out the amount of steam needed based on the UA of the heater, and the pressure drop required will be determined by the tube out temperature. When using this method, user must be certain of the heater configuration and temperature out requirements, as a solution may not be possible if for example the vapour temperature is too low.

* Note the difference with the Demand (UA) method - in that case there is no control on the steam flow, and hence the tube outlet temperature is unconstrained.
* The Demand methods work with multiple steam feeds. In this case, there must be a ''single''' supply connected to a demand source, the others receiving fixed flows. If the fixed flows are inadequate to meet the demand requirement, the demand flow will be adjusted to make up the difference. If the fixed flows are '''greater''' than needed to meet demand, then excess flow will be vented or passed to the condensate outlet.
* Multiple feeds at ''different'' pressures are physically unrealistic and care should be taken in this case. All the feeds will be combined at the demand feed pressure - with the saturation temperature being that of the demand supply. This may give misleading results if there is excess flow from the fixed supplies and they are at different pressures to the demand supply.
|}

* '''Configuration Limits'''
*:To avoid temperature cross over issues:
*# Slurry out Temperature is limited to be <= Condensate out temperature.
*# When using the Demand (UA & TubeT) method, the Shell Pressure drop will be limited by the condensate out temperature, as this temperature cannot be lower than the user defined Tube.TemperatureReqd.
*# UA is currently limited to 10,000 kW/K. If a larger value is needed, use multiple exchangers in series or parallel as appropriate - this will give a better overall representation of large heat transfer models.
*# The Shell and Tube 2 unit will IGNORE any Source, Sink or HX in the reaction file - e.g. if a reaction file with a source is loaded, the source will be ignored and any reactions which have the source species in them will not occur.
*# Vent Mass flow limit allows the user to limit the maximum flow as a percentage of the steam entering the HX. This allows at least some steam to be used for condensing.
*# Tube side flow limit: if tube side flow is below this limit, the HX is considered to be inoperative.
*# Heat loss limit allows the user to define the maximum heat loss as a percent of condenser duty.

=== Method: Evaporating ===

{{Available139}}

The '''cold''' fluid is connected to the '''Shell''' and the hot fluid to the Tube side. The Hot fluid will provide the energy for the evaporation of the cold fluid.

The amount of evaporation could be limited by feed conditions and/or heater configurations (such as HTC and area). Possible outcomes are:
*No Evaporation: The Shell fluid is heated to a temperature below its saturation temperature. (If energy available is less than energy required for evaporation)
*Partial Evaporation: The flash species is partially vaporised at its saturation temperature. (If energy available is less than energy required for Complete evaporation)
*Complete Evaporation: The flash species is completely vaporised and subsequently superheated. (If energy available is greater than energy required for Complete evaporation)
*Forced Evaporate All: If the "EvaporateAll" tickbox is ticked, The flash species is completely vaporised while ignoring the area provided, the shell out temperature will be at the saturation temperature.
**Note that this mode could return an energy balance error where if energy required for Complete evaporation is greater than energy available.

*'''Assumptions'''
*#The Heat Transfer Coefficient is constant; in particular it is not a function of the vapour fraction in the fluid being vaporised.
*# Heat transfer in the Heat Exchanger is defined by the [[#General Theory|LMTD equation]] regardless of the phase composition of the fluid being vaporised.
*# There is no phase change in the hot fluid which supplies energy for the vaporisation.
*# If the fluid is partially vaporised, its final temperature is the saturation temperature of the remaining liquid .
*# The Heat Exchanger will not operate as a Condenser (notwithstanding that this may be physically possible).

===Selecting Operating Methods for Shell and Tube 2===
{| class="wikitable"
|-
! || Method || Condensing Method || Demand Connection || Autoclave || Reactions || EnvironHX || Vent ||Description
|-
|1 || '''Sensible HX''' || || || N/A || allowed || allowed || allowed || Used for simple heat exchange operations between the two sides, with no phase change. The hot side can be connected to either tube or shell. Flow demand network is allowed to pass through on the tube side only.
|-
|2 || rowspan=7|'''Condensing''' || No Demand Calc || || allowed || allowed || allowed || allowed || Steam supply to be specified by the user, unit will condense all the steam to water, Maximum Tube out temperature is limited to be the same as steam feed temperature. If excess amount is supplied, unit will return a warning for possible energy imbalance.
|-
|3 || rowspan=3|Demand (UA) || None (manual) || allowed || allowed || allowed || allowed || Steam supply to be specified by the user, unit will condense steam to water based on the Heater UA (HTC and Area) supplied. Maximum Tube out temperature is limited to be the same as steam feed temperature. If excess amount is supplied, unit will return a warning.
With this configuration, the steam supply must be correctly specified by the user, normally via a General Controller or Set Tag Controller. This is easily implemented as the steam flow required is calculated and displayed as tag VapourFlow.Rqd.
|-
|4 || FlashTrain || allowed || allowed || allowed || allowed || Steam supply to be connected to Flash Tank Vapour outlet, the unit will demand steam from the flash tank based the Heater UA (HTC and Area) supplied. All steam is condensed to water.
|-
|5 || General Demand || allowed || allowed || allowed || allowed ||Steam supply is connected directed or indirectly to a Feeder (with Demand.On selected), unit will demand and condense steam to water based on the Heater UA (HTC and Area) supplied. If excess amount is supplied (minimum in feeder too high), unit will return a warning. '''The Demand (UA) models are essentially uncontrolled, the tube outlet temperature being determined by the area and heat transfer coefficient'''
|-
|6 || rowspan=3|Demand (UA& TubeT) || None (manual) || N/A || N/A || N/A || N/A || Steam supply to be specified by the user, unit will condense all the supplied steam to water. The user also defines the required Tube out temperature, this sets the maximum tube out temperature. The variable in this configuration is the steam feed pressure, if too much steam is supplied, the unit will attempt to drop the pressure of the steam to balance all the specified constraints. If a balance is not found, warnings are given. The minimum shell out temperature (achieved by pressure drop) is limited to the tube out temperature. This method also assumes the user know the exact size of the heater.
With this configuration, the steam supply must be correctly specified by the user, normally via a General Controller or Set Tag Controller. This is easily implemented as the steam flow required is calculated and displayed as tag VapourFlow.Rqd.
|-
|7 || FlashTrain || N/A || N/A || N/A || N/A || Steam supply to be connected to Flash Tank Vapour outlet, the unit will demand steam from the flash tank based the Heater UA and tube outlet temperature supplied. All steam is condensed to water. If the heater area is too big to give the required tube out temperature, the steam pressure is dropped to attempt to achieve a balance. The minimum shell out temperature (achieved by pressure drop) is limited to the tube out temperature. The maximum tube out temperature is limited by the user specified tube out temperature.
|-
|8 || General Demand || N/A || N/A || N/A || N/A || Steam supply is connected directed or indirectly to a Feeder (with Demand.On selected), unit will demand and condense steam to water based on the Heater UA and Tube out Temperature supplied. If excess amount is supplied (minimum in feeder too high), unit will return a warning. All steam is condensed to water. If the heater area is too big to give the required tube out temperature, the steam pressure is dropped to attempt to achieve a balance. The minimum shell out temperature (achieved by pressure drop) is limited to the tube out temperature. The maximum tube out temperature is limited by the user specified tube out temperature. '''Compared to the Demand (UA) configuration, this mode controls (by dropping) the steam pressure to achieve the desired outlet temperature'''
|-
|9 || '''Evaporating''' || || || N/A || N/A || N/A || N/A || {{Available139}} Shell side stream can be evaporated. Hot stream expected to be on tube side.
|-
|}

== Data Sections ==

The default access window consists of several sections:

# '''[[#Shell and Tube Heat Exchanger 2 Page|ShellTube2]]''' tab - This first tab contains general information relating to the unit.
# '''[[Material Flow Section|QTubeIn]]''' - Optional tab, only visible if ''ShowQTubeIn'' is enabled. This page shows the properties of the mixed stream as the feed to the Tube side.
# '''[[Material Flow Section|QShellIn]]''' - Optional tab, only visible if ''ShowQShellIn'' is enabled. This page shows the properties of the mixed stream as the feed to the Shell side.
# '''[[VLE]]''' - Only visible if the unit is in either ''Condensing'' or ''Evaporating'' mode.
# '''[[RB]]''' - Optional tab, only visible if the Reactions are enabled. Please note that the Shell and Tube 2 unit will IGNORE any Source, Sink or HX in the reaction file.
# '''[[#ShellSide Tab|ShellSide]]''' - Optional tab, only visible if the user selects ''Tube Detail'' for the layout.
# '''[[#TubeSide Tab|TubeSide]]''' - Optional tab, only visible if the user selects ''Tube Detail'' for the layout.
# '''[[Common Data Sections#Common Data on Info Tab Page|Info]]''' tab - Contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
# '''[[Links Table|Links]]''' tab, contains a summary table for all the input and output streams.
# '''[[Audit]]''' tab - Contains summary information required for Mass and Energy balance. See [[Model Examples]] for enthalpy calculation Examples.

===Shell and Tube Heat Exchanger 2 Page===
'''Unit Type: ShellTube2''' - The first tab page in the access window will have this name.

{| border="1" cellpadding="5" cellspacing="0" align="center"
| '''Tag (Long/Short)'''||'''Input / Calc'''||'''Description/Calculated Variables / Options'''
|-
{{Common Data on First Tab Page}}
|-
| colspan="3" font style="background: #ebebeb" |

=== Requirements ===
|-
| On|| Tick Box || Switches the Heat Exchanger on/off
|-
| rowspan=3|Method|| Sensible HX || This will allow sensible heat exchange between two streams. No phase change will take place automatically. Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| Condensing || This is used to condense the steam. Steam must be connected to Shell In. Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| Evaporating || {{Available139}} This is used to evaporate a stream, usually water. The stream to be evaporated must be connected to Shell In while the hotter stream must be connected to Tube In.
|-
| colspan="3" font style="background: #ebebeb" | ''(Bypass functionality is only {{Available139||y}}.)''
|-
| rowspan=3|Bypass.Option<br>(Only visible if ''Method'' is set to '''Sensible HX''')|| No Bypass || Full Tube and shell flows will be used for heat transfer calculations.
|-
| Bypass Shell Feed || user can specify a portion of the shell feed to bypass the heat transfer calculations, this is equivalent to adding a split to the shell feed, the bypassed amount will be added to the shell out stream.
|-
| Bypass Tube Feed || user can specify a portion of the tube feed to bypass the heat transfer calculations, this is equivalent to adding a split to the tube feed, the bypassed amount will be added to the tube out stream.
|-
| rowspan=3|Bypass.Control<br>(Only visible if ''Bypass.Option'' is set to '''Bypass Shell Feed''' or '''Bypass Tube Feed''')|| Fixed Fraction || user can specify a fixed portion of the shell/tube feed to bypass the heat transfer calculations.
|-
| Shell Outlet T || the portion of the shell/tube feed to bypass the heat transfer calculations is adjusted to meet the user defined shell outlet temperature.
|-
| Tube Outlet T || the portion of the shell/tube feed to bypass the heat transfer calculations is adjusted to meet the user defined tube outlet temperature.
|-
| Bypass.FracReqd || Input || Only displayed if ''Bypass.Control'' = '''Fixed Fraction'''.
|-
| Bypass.T_Reqd || Input || Only displayed if ''Bypass.Control'' is set to '''Shell Outlet T''' or '''Tube Outlet T'''.
|-
| Bypass.FracMax || Input || Only displayed if ''Bypass.Option'' is set to '''Bypass Shell Feed''' or '''Bypass Tube Feed'''.
|-
| rowspan=3|CondensingMethod <br>(Only visible if ''Method'' is set to '''Condensing''')|| No Demand Calc|| The Steam addition is manually specified by the user, all steam supplied (less vent) will be condensed. Duty will be based on Tot.Cond.Duty (total condensing duty). NOTE: Duty may not equal to TheoreticalDuty (calculated from HX UA and LMTD) as steam input is manual. Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| Demand (UA) || The steam demand is calculated base on the user specified Heater HTC and Area (UA). Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| Demand (UA&TubeT)|| The steam demand is calculated base on the user specified Heater HTC, Area and the tube outlet temperature. Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| rowspan=3|DemandConnection<br>(Only visible if ''CondensingMethod'' is set to one of the '''Demand''' methods)|| None (Manual) || Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| FlashTrain || The steam supply comes from a Flash Tank and the ''Flash Tank - Heater'' is in a Flash train mode. Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| GeneralDemand || The steam supply comes from (directly or indirectly) a Feeder with Demand.on selected. Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]
|-
| Tube.TemperatureReqd / Tube.T_Reqd || Input || Only visible if the ''CondensingMethod'' is set to '''Demand (UA & Tube T)'''. User specified Tube out Temperature. This is also the maximum Temperature for the Tube outlet stream.
|-
| Reactions|| List box || Switches the Reactions on/off. Reactions occur on the tube side only and the Shell and Tube 2 unit IGNORES any Source, Sink or HX in the reaction file.
|-
| ShellSide.On|| Tick Box || Only visible if ''CondensingMethod'' is set to '''No demand calc''' or '''Demand (UA)'''. Use this to effectively switch the Heat Exchanger on/off while solving.
|-
| Autoclave || Tick Box || Only visible if ''Method'' = '''Condensing'''. If this is enabled the unit will use temperature difference rather than LMTD in heater calculations. Calculates MTD based on difference between condensing temperature and primary (tube) outlet temperature. This simulates a fully mixed autoclave with internal steam heating.
|-
| Use.RMTD || Tick Box || Only visible if Reactions are 'On' and ''CondensingMethod'' = '''Demand (UA)'''. This enables an alternative calculation of MTD, accounting for the reaction heat. See theory above.
|-
| valign="top" | IgnoreSteamFlow || valign="top" | Tick Box || This is only available if ''CondensingMethod'' = '''Demand (UA)'''. Adjust steam feed rate to match duty and report excess or low flow conditions. When the flash train model has converged correctly, the steam flow rate will be matched and an error is not reported.<br>'''Note:''' If this option is enabled and
# The steam flow to the Heat Exchanger is LESS than required, extra steam will be added to the Heat Exchanger, i.e. Condensate Flow > Steam to HX; or
# The steam flow to the Heat Exchanger is MORE than required, the extra steam will be 'thrown away' from the Heat Exchanger, i.e. Condensate Flow < Steam to HX.
|-
| Flow.Damping || Input || This is only available if ''CondensingMethod'' = '''Demand (UA)'''. In solving macro models, there may be situations when the solver overshoots and fails to converge. This is because the demand from the model is interacting with supply from Flash Tanks. If the unit model steam flow and pressure seems to be oscillating about, then put in a value of 0.8 for the flow damping. This will stabilize the oscillations and allow the model to converge. It will slow the overall convergence rate if used when unnecessary, so only turn this on (change the default value of 0.0) if flash trains are not converging.
|-
| EnvironHX || Tick Box || Switches the environmental heat exchanger sub model on/off, used for additional heat losses. This is NOT available if ''CondensingMethod'' = '''Demand (UA & TubeT)'''.
|-
| rowspan=3|Env.Model|| colspan="2" font style="background: #ebebeb" | Only available if EnvironHX has been selected. For EnvironHX to perform correctly, the HOT stream must be connected to the Shell side.
|-
| None|| No environmental heat loss.
|-
| FixedHeatFlow || Fixed Environmental heat loss for the unit operation.
|-
| Env.HeatFlowReqd || Input/Calc || Only shown if EnvironHX has been enabled. The amount of heat lost to the environment.
|-
| Env.MaxLossFrac || Input/Calc || Only shown if EnvironHX has been enabled. The maximum fraction of heat lost to the environment as a percent of HX duty.
|-
| rowspan=2|Layout|| '''Overall''' || User specifies the overall heater area and HTC
|-
| '''TubeDetail'''|| User can specify the tube side in more detail. Refer to the Tubeside Tab for details.
|-
| HTC || Input/Calc || If the '''Overall''' method is selected then this field allows the user to specify the heat transfer coefficient. <br> If the '''TubeDetail''' method is selected then this field shows the calculated heat transfer coefficient (the HTC is specified on the ShellSide/TubeSide tabs).
|-
| Area || Input/Calc || If the '''Overall''' method is selected then this field allows the user to specify the heat transfer area. <br> If the '''TubeDetail''' method is selected then this field shows the calculated heat transfer area (based on user specified information on the TubeSide tab). 
|-
| LMTDFact || Input || User specified LMTD factor
|-
| VentMassFlowReqd|| Input || Only available if ''CondensingMethod'' = '''No demand calc''' or '''Demand (UA)'''. User specified amount of steam to be vented (This could be limited based on steam available)
|-
| Vent.MassFracOfFeed|| Input || Only available if ''CondensingMethod'' = '''No demand calc''' or '''Demand (UA)'''. User specified maximum fraction of steam to be vented based on feed steam to the HX.
|-
| Tube.LowQmLimit|| Input || User specified minimum tube side flow, if flow is lower than the limit, then the HX is considered to be inoperative.
|-
| EvaporateAll || Tick Box || {{Available139}} Only displayed if ''Method'' = '''Evaporating'''. All of the VLE species in the shell side stream will be evaporated, i.e. evaporation will not be limited by area.
|-
| colspan="3" font style="background: #ebebeb" | '''Options'''
|-
| ShowQTubeIn || Tick Box || QTubeIn and associated tab pages (e.g. Sp) will become visible, showing the properties of the combined Tube feed stream. See [[Material Flow Section]]. This will be prior to any sub-model actions (e.g. Reactions).
|-
| ShowQShellIn || Tick Box || QShellIn and associated tab pages (e.g. Sp) will become visible, showing the properties of the combined Shell feed stream. See [[Material Flow Section]]. This will be prior to any sub-model actions.
|-
| ShowQTubeOut || Tick Box || QTubeOut and associated tab pages (e.g. Sp) will become visible, showing the properties of the combined Tube side outlet stream. See [[Material Flow Section]].
|-
| ShowQShellOut || Tick Box || QShellOut and associated tab pages (e.g. Sp) will become visible, showing the properties of the combined Shell side outlet stream. See [[Material Flow Section]].
|-
| TrackShellFlowWhenOff || Tick Box || Only used when model is Off. Gives a warning condition when the model is off and there is shell side feed. For the Condensing ''Method'' with FlashTrain ''DemandConnection'' then this warning is always given when the model is off and there is shell side feed flow. {{Available139|32033}}
|-
| colspan="3" font style="background: #ebebeb" | '''Calculation Modes''' (Only shown if Tube Detail is selected for Layout)
|-
| rowspan=2|TSdPCalc|| Fixed || User specified pressure drop for the tubeside.
|-
| Full ||
|-
| TS.RqdPressureDrop|| Input || Allows user defined pressure drop for the tube side. Only shown if ''TSdpCalc'' is set to ''Fixed''.
|-
| TS.Scaling|| Tick Box || Allows scaling for the Tubeside (will display extra fields on TubeSide Tab page).
|-
| TS.Blockage|| Tick Box || Allows simulation of blockage on the Tubeside (will display extra fields on TubeSide Tab page).
|-
| colspan="3" font style="background: #ebebeb" |

=== Results ===
|-
| Operating|| font style="background: #ebebeb"|On/Off || Returns the operating status of the HX. If the HX is switched off, ShellSide is switched off or tube side flow < Tube.LowQmLimit, this will be shown 0 (inoperative), otherwise, it will be shown as 1 (operating).
|-
| U*A / UA|| font style="background: #ebebeb"|Calc || The heat exchanger UA. Note that if the product of ''HTC'' and ''Area'' is below a minimum limit, the value shown here and used in the model calculations is a non-zero low limit.
|-
| LMTD|| font style="background: #ebebeb"|Calc || The calculated log mean temperature difference. If the heat exchanger has Superheated Steam condensing on the shell side, then the LMTD method will produce small inaccuracies, please see [[Log Mean Temperature Difference (LMTD) Discussion]].
|-
| RMTD|| font style="background: #ebebeb"|Calc || It is only calculated and used if the "Use.RMTD" option is selected, otherwise RMTD is set to equal LMTD. The Reactive Mean Temperature Difference - this method of calculating the log mean temperature difference includes the temperature change due to the reactions.
|-
| TheoreticalDuty / TheorDuty|| font style="background: #ebebeb"|Calc || The theoretical duty of the heat exchanger.
|-
| Duty|| font style="background: #ebebeb"|Calc || The calculated Heater Duty
|-
| DutyDiff|| font style="background: #ebebeb"|Calc || The difference between theoretical and calculated Heater Duty.
|-
| DutyDiff.RelErr|| font style="background: #ebebeb"|Calc || The difference between theoretical and calculated Heater Duty as percent (relative error).
|-
| Reaction.Ht || font style="background: #ebebeb"| Calc || This is only visible if Reactions are enabled. This field displays the energy from the reactions referenced to RB feed temperature and standard pressure.
|-
| Reaction.Ht@0 || font style="background: #ebebeb"| Calc || This is only visible if Reactions are enabled. This field displays the energy from the reactions referenced to 0°C and standard pressure.
|-
| TheoreticalArea / TheorArea|| font style="background: #ebebeb"|Calc || The calculated heat exchanger area required to handle the duty.
|-
| DutyDirection || font style="background: #ebebeb"|Calc || Only visible if ''Method'' = '''Sensible HX'''. The direction of heat flow (from hot to cold), 'Shell to Tubes' or 'Tubes to Shell'.
|-
| Tot.Cond.Duty || font style="background: #ebebeb"|Calc || Only visible if ''Method'' = '''Condensing'''. The total duty from condensing steam.
|-
| HeatFlow || font style="background: #ebebeb"|Calc || The heat loss due to environmental heat exchange.
|-
|FlashComponent / FlashComp ||font style="background: #ebebeb" |Display|| Displays the flashing component used for the VLE calculation. This can be selected from the VLE tab.
|-
|Evap.ExtraHeatFlow|| font style="background: #ebebeb"|Calc || {{Available139}} Only displayed when the following conditions are met: ''Method'' = ''Evaporating'', the ''Evaporate All'' option is selected, and after solving, the unit requires additional energy to fully evaporate the shell contents.
|-
| Evap.FinalState || font style="background: #ebebeb"|Calc || {{Available139}} Only displayed when ''Method'' = '''Evaporating''' and after project solve. The description of the solved solution.
<syntaxhighlight>(0) Forced Evaporate All
(1) Shell Inlet T > Tube Inlet T
(2) Can't Boil - No Area Restriction
(3) Can't Boil - Area Restriction
(5) Partial vapourisation at Sat T - No Area Limit
(6) Partial vapourisation at Sat T - Area Limit
(10) Maximum Superheat - No Area Limitation
(11) Maximum Superheat Limited by Heat Exchanger
(12) Crossover
(13) Partial vapourisation at Sat T - No Area Limit
(15) Superheat - Shell Limit
(16) Superheat - Area(S) Limit</syntaxhighlight>
|-
| Evap.SolveCase || font style="background: #ebebeb"|Calc || {{Available139}} Only displayed when ''Method'' = '''Evaporating''' and after project solve. The solved condition, described by case number, the matching description is displayed in the "Evap.FinalState".
|-
| Evap.TargetDuty || font style="background: #ebebeb"|Calc || {{Available139}} Only displayed when ''Method'' = '''Evaporating''' and after project solve.
|-
| Evap.RequiredArea || font style="background: #ebebeb"|Calc || {{Available139}} Only displayed when ''Method'' = '''Evaporating''' and after project solve. The Minimum area required for complete evaporation of VLE species in Shell side.
|-
| colspan="3" font style="background: #ebebeb" |

=== Tube Side ===
|-
| TemperatureIn / Ti || font style="background: #ebebeb"|Calc || Tube in temperature.
|-
| TemperatureOut / To|| font style="background: #ebebeb"|Calc || Tube out temperature. This is the temperature of non-bypassed flow.
|-
| DeltaT / dT|| font style="background: #ebebeb"|Calc || Temperature change on tube side (To - Ti).
|-
| PressureIn / Pi || font style="background: #ebebeb"|Calc || Tube in pressure.
|-
| PressureOut / Po|| font style="background: #ebebeb"|Calc || Tube out pressure.
|-
| PressChange / dP || font style="background: #ebebeb"|Calc || Pressure drop in the tube side (Po - Pi).
|-
| MassFlow / Qm|| font style="background: #ebebeb"|Calc || The mass flowrate going through the tube side. This is the mass flow that is '''NOT''' bypassed.
|-
| colspan="3" font style="background: #ebebeb" |

=== Shell Side ===
|-
| TemperatureIn / Ti|| font style="background: #ebebeb"|Calc || Shell in temperature.
|-
| TemperatureOut / To|| font style="background: #ebebeb"|Calc || Shell out temperature. This the temperature of non-bypassed flow.
|-
| DeltaT / dT|| font style="background: #ebebeb"|Calc || Temperature change on shell side (To - Ti).
|-
| PressureIn / Pi || font style="background: #ebebeb"|Calc || Shell in pressure.
|-
| PressureOut / Po|| font style="background: #ebebeb"|Calc || Shell out pressure.
|-
| PressChange / dP|| font style="background: #ebebeb"|Calc || Pressure drop in the shell side (Po - Pi).
|-
| MassFlow / Qm|| font style="background: #ebebeb"|Calc || The mass flowrate going through the shell side, less any amount vented. This is the mass flow that is '''NOT''' bypassed.
|-
| Shell.DmdQm|| font style="background: #ebebeb"|Calc || Only visible if part of a flash train. This is the amount of steam needed from connected flash train units (flash tank or steam feeders), not including any fixed amount of steam input.
|-
| Shell.FxdQm|| font style="background: #ebebeb"|Calc || Only visible if part of a flash train. This is the amount of steam added in manually, thus not from connected flash train units. Note this portion of steam addition is not included in the pressure calculation of the flash train group.
|-
| colspan="3" font style="background: #ebebeb" |
=== Overall Unit - Including Bypass ===
|-
| colspan="3" font style="background: #ebebeb" | ''(The following set of results are only shown if ''Bypass.Option'' is set to '''Bypass Shell Feed''' or '''Bypass Tube Feed'''. {{Available139}})''
|-
| Bypass.Fraction / Frac || font style="background: #ebebeb"|Calc || The bypassed fraction.
|-
| Bypass.MassFlow / Qm|| font style="background: #ebebeb"|Calc || The bypassed flow.
|-
| colspan="3" font style="background: #ebebeb" |'''Tube Side'''
|-
| TemperatureIn / Ti || font style="background: #ebebeb"|Calc || Tube in temperature.
|-
| TemperatureOut / To|| font style="background: #ebebeb"|Calc || Tube out temperature. This is the final temperature of the combined stream, including bypassed flow.
|-
| DeltaT / dT|| font style="background: #ebebeb"|Calc || Temperature change on tube side (To - Ti).
|-
| PressureIn / Pi || font style="background: #ebebeb"|Calc || Tube in pressure.
|-
| PressureOut / Po|| font style="background: #ebebeb"|Calc || Tube out pressure.
|-
| PressChange / dP || font style="background: #ebebeb"|Calc || Pressure drop in the tube side (Po - Pi).
|-
| MassFlow / Qm|| font style="background: #ebebeb"|Calc || The total mass flowrate on the tube side, '''including''' bypassed flow.
|-
| colspan="3" font style="background: #ebebeb" |'''Shell Side'''
|-
| TemperatureIn / Ti || font style="background: #ebebeb"|Calc || Shell in temperature.
|-
| TemperatureOut / To|| font style="background: #ebebeb"|Calc || Shell out temperature. This is the final temperature of the combined stream, including bypassed flow.
|-
| DeltaT / dT|| font style="background: #ebebeb"|Calc || Temperature change on shell side (To - Ti).
|-
| PressureIn / Pi || font style="background: #ebebeb"|Calc || Shell in pressure.
|-
| PressureOut / Po|| font style="background: #ebebeb"|Calc || Shell out pressure.
|-
| PressChange / dP || font style="background: #ebebeb"|Calc || Pressure drop in the shell side (Po - Pi).
|-
| MassFlow / Qm|| font style="background: #ebebeb"|Calc || The total mass flowrate on the shell side, '''including''' bypassed flow.
|-
| colspan="3" font style="background: #ebebeb" |
''' Vent''' (only visible if Vent stream is connected)
|-
| Vent.MassFlow / Qm|| font style="background: #ebebeb"|Calc || The mass flowrate going through the vent.
|-
| Vent.NonCond.Qm|| font style="background: #ebebeb"|Calc || The mass flowrate of non-condensables going through the vent.
|-
| colspan="3" font style="background: #ebebeb" |

=== Calculated Vapour Flow Demand ===
|-
| VapourFlow.Reqd|| font style="background: #ebebeb"|Calc || The calculated steam flow to meet the Heater requirements. When the heater is not in GeneralDemand or FlashTrain mode, use a General controller or SetTag Controller to get this value to set the steam flowrate.
|-
| VapourFlow.Actual|| font style="background: #ebebeb"|Calc || The actual steam flow to heater.
|-
| VapourFlow.Error|| font style="background: #ebebeb"|Calc || The mass imbalance in the unit operation. This will warn the user if the amount of steam supplied exceeds the heater requirements. Most common when the heater is not in demand mode and the steam flow has not been set up to auto adjust.
|-
| VapourFlow.RelErr|| font style="background: #ebebeb"|Calc || The relative mass imbalance error in the unit operation. This will warn the user if the amount of steam supplied exceeds the heater requirements.
|-
| Condensate.Demand|| font style="background: #ebebeb"|Calc || This is only shown if the CondensingMethod selected is Demand (UA). This is the amount of steam which is passed back to the flash train.
|-
| LastMassFlow|| font style="background: #ebebeb"|Calc || This is only shown if the CondensingMethod selected is Demand (UA). This is the last mass flowrate through the shell side. This is used in combination with Flow.Damping.
|-
| colspan="3" font style="background: #ebebeb" |

=== Flash Train Macro Model ===
Note: Extra fields are visible if the unit is part of a Flash Train. These fields are described below. Please refer to '''[[ Flash Train]]'''.
{{Flash Train Macro Data Table Section | Cond = Yes | Evap = No | Name1=FT_001 | Name2=ST_001 | UnitOp=Shell and Tube Heat Exchanger }}
|}

=== ShellSide Tab ===

This tab page is only shown if "Method=Condensing" and "Layout = Tube Detail".

{| border="1" cellpadding="5" cellspacing="0"
| width=120|'''Tag (Long/Short)'''||width=120|'''Input / Calc'''||width=1000|'''Description/Calculated Variables / Options'''
|-
| colspan="3" font style="background: #ebebeb" |'''Requirements'''
|-
| ShellSideHTC|| Input || Shell side heat transfer coefficient.
|}

=== TubeSide Tab ===

This tab page is only shown if "Layout = Tube Detail".

{| border="1" cellpadding="5" cellspacing="0"
| width=120|'''Tag (Long/Short)'''||width=120|'''Input / Calc'''||width=1000|'''Description/Calculated Variables / Options'''
|-
| colspan="3" font style="background: #ebebeb" |'''Requirements'''
|-
| Tube.conductivity|| Input || Tube side conductivity.
|-
| NumberTubes|| Input || User specified number of tubes used to calculate the Heater area.
|-
| TubeLength|| Input || User specified tube length used to calculate the Heater area.
|-
| TubeID|| Input || User specified inner diameter used to calculate the Heater area.
|-
| TubeOD|| Input || User specified outside diameter used to calculate the Heater area.
|-
| TubePlateThickness || Input || User specified tube plate thickness.
|-
| TubeSidePasses|| Input || Tube side passes, used to configure the blockage.
|-
| SpecifyViscosity || Tick Box|| This allows the user to specify a viscosity, used in the dP calculation.
|-
| UserViscosity || Input ||Only visible if the 'SpecifyViscosity' box is ticked. User defined viscosity.
|-
| TubeRoughness || Input || Tube Roughness, used in the dP calculation.
|-
| EntranceCc|| Input || The contraction coefficient for entrance losses.
|-
| ExitCc|| Input || The contraction coefficient for exit losses.
|-
| colspan="3" font style="background: #ebebeb" |'''HeatTransfer'''
|-
| TubeSideHTC|| Input || Tube side heat transfer coefficient.
|-
| Scale.Thick|| Input || Tubeside scale thickness. Visible with TS.Scaling selected.
|-
| Scale.Cond|| Input || Tubeside scale conductivity. Visible with TS.Scaling selected.
|-
|-
| colspan="5" font style="background: #ebebeb" |'''''Pass Tube Blockage'''''
|-
|Pass || font style="background: #ebebeb" |Pass_Number|| This is defined by the TubeSidePasses Value
|-
|Blockage || Input || The blockage in the pass, as percentage, maximum value is 99%
|-
| dPIO || font style="background: #ebebeb"|Calc ||
|-
|dPFr ||font style="background: #ebebeb"|Calc ||
|-
| dPTot ||font style="background: #ebebeb"|Calc ||
|-
| colspan="3" font style="background: #ebebeb" |'''Results'''
|-
| AreaReduction || font style="background: #ebebeb"|Calc || Only visible if the TS.blockage is used. This is the heat transfer area reduction caused by the blockage(s).
|-
| CalcArea || font style="background: #ebebeb"|Calc || The calculated heat exchange area.
|-
| TS.HTC || font style="background: #ebebeb"|Calc || Tube side HTC used.
|-
| TS.Vel || font style="background: #ebebeb"|Calc || Tube side velocity. Not visible if the TS.blockage is used.
|-
| TS.G || font style="background: #ebebeb"|Calc || The average mass flow velocity.
|-
| colspan="3" font style="background: #ebebeb" |'''In'''
|-
| TSin.Re|| font style="background: #ebebeb"|Calc || Tube side inlet Reynolds number
|-
| TSin.ft|| font style="background: #ebebeb"|Calc ||
|-
| TSin.dPdL|| font style="background: #ebebeb"|Calc ||
|-
| colspan="3" font style="background: #ebebeb" |'''Out'''
|-
| TSout.Re|| font style="background: #ebebeb"|Calc || Tube side outlet Reynolds number
|-
| TSout.ft|| font style="background: #ebebeb"|Calc ||
|-
| TSout.dPdL|| font style="background: #ebebeb"|Calc ||
|-
| colspan="3" font style="background: #ebebeb" |'''Total'''
|-
| TS.dPIO|| font style="background: #ebebeb"|Calc || Tube side pressure drop
|-
| TS.Calc_dP|| font style="background: #ebebeb"|Calc || The calculated tube side pressure drop
|}

=== Vent Stream ===

The user can specify an amount of steam to be lost from the shell without contacting the tubes, QmVentRqd. If a vent stream is connected the steam will be sent to this link. If the user has not connected a vent stream, this amount of steam will be shown in the tab 'Last Vent' (however, this is not recommended - if the user expects steam to vent then it is good practice to connect a vent stream to the unit) If the amount of steam sent to the unit is less than the user defined amount, QmVentRqd, the unit will flag the user that the specified conditions cannot be met.

Any non-incondensable gases in the steam will also be vented via the vent stream.

If excess steam is sent to the shell and tube heat exchanger, i.e. it is not all condensed in the unit, then the excess steam will report to the condensate line. This is true even if the user has connected a vent stream to the unit.

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=HeatExchange | DllSubGroup=Heat Transfer | UnitOp=Shell & Tube(2) | Group=Energy Transfer}}

== Hints and Comments ==

=== Operation Mode selection and Shortcomings ===

Please see [[#Selecting_Operating_Methods_for_Shell_and_Tube_2|Selecting Operating Methods for Shell and Tube 2]]

The flow demand network can be passed through the tube side of the heat exchanger.

=== General Configuration Hints ===
#The user MUST use Steam Condensing mode if the unit is required to condense the steam entering the shell.
#For Steam Condensing operation modes, the hot side MUST be connected to the Shell_In and the cold side MUST be connected to the Tube_In.
#Ensure that the HTC and Area are correct. If these variables are not configured, the heat exchanger will not operate as expected.
#The Environmental Heat Transfer (EnvironHX) occurs between the shell side fluid and the environment prior to heat exchange. If heat loss is enabled, then less heat will be available for heat transfer to the tube side.
#*In the case of flash train configuration, more steam will be required to satisfy the heater requirements.
#*For Sensible HX operation modes with user specified environment heat loss, the hot side MUST be connected to the Shell_In and the cold side MUST be connected to the Tube_In.
#If the heat exchanger is disabled, but the EHX is enabled, then the shell side stream will still transfer heat to the environment.
#If the unit has a bad mass and energy balance this could be caused by an excess of steam flowing to the unit.
#When using the Demand (UA & TubeT) method:
:*user will be warned if the HTC / Area or Steam Supply Temperature is too low to achieve the required temperature. If this warning appears, please adjust the heater configuration accordingly.
:*If the heater area is too big, the steam pressure will be dropped to attempt to satisfy the tube out temperature requirement. The steam Pressure change is limited by the Tube Out Temperature, thus, the condensate temperature cannot be lower than the Tube out Temperature.
:*If the steam supply is in excess, there will be a mass imbalance in the model, user will be given a warning, to prevent this, make sure the steam supply is auto adjusted via General controller / Set Tag Controller or put into demand mode (where possible).

=== Hints on using a Shell & Tube Heat Exchanger ===

a) Some of the intended uses of the heat exchanger model in ProBal mode are:

*To help size the heat exchanger area with known flowrates - In this case, we will specify the Steam flowrate, Steam properties such as T and P, HTC and have a "controller" calculate the HX area to achieve a certain cooling water outlet temperature (T<sub>o</sub>).

*To find out the steam requirements based on known heat exchanger size and steam properties. - In this case, we will input HX HTC & area, as well as the steam properties (T & P), then through a controller, work out the steam flowrate to achieve a certain cooling water outlet temperature T<sub>o</sub>.

*As part of the [[Flash Train]]. NOTE that when the HX is set up as part of a flash train, in fully condensing mode, it behaves differently in that you can not "set" any flows to the HX, the flow is governed by the size of the HX. As part of the flash train, the fully condensing HX will calculate the steam amount required and "demand" this of the preceding units.

b) In ProBal mode, if you are using a "stand-alone" heater, you must control the steam flow by setting the Steam flowrate - typically a ''Qm_Rqd'' through a controller or set the Feeder to Demand mode. Changing the pressure or temperature of the Steam in the feed would not change the steam flowrate without the use of some form of control logic.

c) The Demand modes obviate the need to use a flow controller and will help convergence of complex flow sheets since the outlet temperature from the exchanger is fixed. In general, you should not never to use flow controllers in a heat exchager model.

d) A pressure drop can be specified in the pipes between flash tanks and/or heat exchangers. This may be required for a flash train arrangement. The CondensingSteam - Demand (UA & TubeT) has built in pressure drops for the Steam in, this might be a good model to use if the user wants to find out what the pressure drops are using some known temperature profile.

=== Comments on Heat Balance around the Heater ===

The HX LMTD will contain a small error when the HX is in '''Fully condensing''' mode with superheated steam as its feed. Please see [[Log Mean Temperature Difference (LMTD) Discussion]] for further information.

=== Heat of Reaction ===

Having reaction heat in a heat exchanger adds a lot of complication to the overall analysis. For example if the cold stream generates enough heat through reactions, it may end up ''hotter'' than the hot stream, and hence the direction of heat transfer will reverse!

Even without these pathological situations, the reaction heat can significantly change the thermal profile in the exchanger (i.e. the temperatures on the hot and cold sides), and hence has a significant influence on the effective mean temperature difference and total overall heat transfer.

SysCAD determines the reaction heat by evaluating a '''Reaction Block''' which can be added to the model. If the reaction heat is negligible compared to the overall heat transfer, then it is sufficient to use the LMTD formulation: the calculated reaction heat is just added or removed from the total heat transfer to the tube side.

If the reaction heat is of the same order of magnitude as the heat transfer, then the RMTD option can give a better estimate of heat transfer.

==== RMTD Analysis ====

The ''Reactive Mean Temperature Difference'' is calculated by assuming that reaction heat is ''uniformly'' generated within the fluid. (If the reaction rate and heat of reaction is strongly temperature dependent, then the exchanger could be divided into a number of units in series, with different reaction rates and reaction heat production)

This distributed heat production or absorbtion modifies the overall thermal transfer. The theoretical development of the model assumes that heat transfer is always from the hot to the cold side: if the overall reaction heat is such as to reverse this, then the model fails and will fall back on a LMTD calculation with a warning. In this case you should look closely at the model to see if the reaction heat being generated is realistic.

Sugar Crusher

2025-08-08T16:13:27Z

John.McFeaters: /* Mill Operation */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=3}}
----
{{TOC}}
== General Description ==

The sugar crusher unit operation is available with the Sugar add-on.

The sugar crusher receives shredded cane (or bagasse from an upstream mill) and passes it through rolls to squeeze juice out of it. There may be an optional imbibition streams added to help wash out sucrose rich juice. There is a product juice stream, a delivery (or product) bagasse stream and a vent stream exiting the crusher.

All streams entering the crusher are assumed to mix perfectly and then the flow of solids, sucrose and impurities are split between juice, bagasse and vent to meet the specified operating parameters.

Solids are split between the juice and delivery bagasse streams according to the user specified separation efficiency.

Water and various solutes may be split in different relative proportions to the juice and bagasse streams to allow the product streams to have different Brix, overall purity and specific impurities ratios. The splits are calculated to satisfy the user specified ''Imbibition Coefficient, Ic'' and when the optional ''Purity Control'' is selected a user specified purity ratio. The feed and product streams in sugar crusher would typically use the [[Sugar Species Model]].

The volumetric flow of liquid going to the delivery bagasse stream is determined by the volumetric flow of solids to the bagasse stream and the user specified ''Filling Ratio, C'' and ''Re-absorption Factor, K''.

The crusher model includes optional heat loss to the environment and there are several different heat loss models available. The crusher also includes the option to specify evaporation rate from it
and this is included in the energy balance.

Any vapours in the input streams or from evaporation are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams and there is no vent connected.

The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant Model - Environment]]).

The crusher has the option to use a ''user specified reference stream''. Data from this stream may then be used for doing purity, extraction and volumetric flow calculations relative to the reference stream. Typically the reference stream would be the shredded cane going into the first crusher in a milling train.

== Inputs and Outputs ==

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max''' ||  
|-
| FeedBag || Required || In || 1 || 1 || Feed Bagasse to the Crusher - shredded cane or bagasse from a previous mill stage.
|-
| Imbibition || Optional || In || 0 || 5 || Optional Imbibition Streams.
|-
| Juice || Required || Out || 1 || 1 || Primarily liquid squeezed from the bagasse - may have some solids content.
|-
| Bagasse|| Required || Out || 1 || 1 || Delivery (or Product) Bagasse - most of the input solids, with some liquid.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapours - not required if there are no vapours present.
|-
|}

NB Aqueous Sucrose must be present in the Feed Bagasse stream or an error will be reported.

== Behavior when Model is OFF ==

The sugar crusher unit may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off it is basically bypassed and the following behavior occurs:
* All material in streams connected to ''Feed'' will flow straight through to the product Bagasse stream with no changes or heat exchange.
* All material in streams connected to ''Imbibition'' will flow through to the product Juice stream with no changes or heat exchange.
* There will be no heat transfer to the environment.

NB any gases in either feed or imbibition streams will remain with those streams when the unit is off.

== Model Theory ==

The input streams to the crusher are the ''Feed Bagasse'' stream which is the shredded sugar cane or bagasse from a previous mill stage and the ''Imbibition'' stream which is usually lower Brix juice from a downstream mill stage or water. All of the input and output streams are a mixture of solids and liquids. The solids are primarily plant fiber but may contain mud and other material. The liquids are primarily sucrose-water solutions with some aqueous impurities. NB Brix refers to ''all'' solutes in the liquid phase - or basically everything except water.

The model allows for multiple imbibition streams. All the feed and imbibition streams are assumed to mix perfectly in the crusher. The flows of solids, Brix and water must then be split to satisfy the user specified operating parameters.

The output streams are ''Juice'' which is primarily liquid although may have some solids, ''Bagasse'' which is most of the fiber and some liquid and a ''Vent'' for gases. These are shown in the flow chart below.

'''Gases''' - Any gases present in any of the input streams are split off and go to the vent stream. If there is no vent attached, the gases are sent out with the juice stream and a warning is displayed that there are gases present, but no vent.

'''Solids''' - Solids from mixed input stream split according to the user specified ''Separation Coefficient'' (which is the mass fraction of solids reporting to bagasse). Generally, most of the solids report to the bagasse stream and any remaining solids report to the juice stream.

'''Liquids''' - The overall split of liquid between juice and bagasse streams is calculated to give the required volumetric flow of juice going to the product bagasse stream. This flow is determined by the volumetric flow of solids, the ''Filling Ratio'' and the ''Re-absorption Factor''. The required volumetric flow ratio of juice to solids is given by; Vj/Vs = (Re-absorption Factor - Filling Ratio) / Filling Ratio. (NB the mass of liquid going to bagasse depends on the liquid density).

The individual split of water and Brix is based on the ''Imbibition Coefficient, Ic'' which is a measure of actual Brix extraction to theoretical Brix extraction. It is possible to have an imbibition coefficient that is greater or less than than one and the Brix of the juice and bagasse streams may be different. When the imbibition coefficient is one the Brix of the juice and bagasse streams are equal, when it is less than one, the bagasse Brix is higher than the juice Brix and when it is greater than one the juice Brix is higher then the bagasse Brix. The SysCAD sugar crusher model splits water and Brix to match the imbibition coefficient with the constraint that the required volume flow to delivery bagasse must be met (and also that various constraints on impurities are met so that the ratio of sucrose to impurities is may also be adjusted between the bagasse and juice streams - see below).

A theoretical Brix is calculated assuming a perfect mixture of all the streams coming in and the imbibition coefficient is the actual Brix mass flow to juice divided by the theoretical Brix mass flow to juice.

*<math> \text{Imbibition Coefficient, Ic} = \frac {(\text{Brix into Crusher} \quad - \quad \text{Brix in Delivery Bagasse} \;)}{(\text{Brix into Crusher} \quad- \quad \text{Theoretical Brix in Delivery Bagasse} \;)}</math>

'''Impurities''' - The impurities include ''all'' solutes other than sucrose. The sugar crusher model identifies four specific impurities that normally derived from the analysis of bagasse. These species are managed individually in the crusher model and must be present in the species data base (although their mass flows may be set to zero). The species and the control of them is as follows;

# Reducing Sugars - the ratio of reducing sugars to Pol is assumed to be constant between the feed bagasse and product bagasse.
# Soluble Ash - the ratio of Soluble Ash to Brix is assumed to be constant between the feed bagasse and the product bagasse.
# Soluble Protein - the ratio of Soluble Protein to Brix is assumed to be constant between the feed bagasse and the product bagasse.
# Soluble Other - Soluble Other includes the other soluble species found in sugar cane and not specifically identified as a Reducing Sugar, Ash or Protein. The concentration of Soluble Other may be varied in the model in order to control the sugar purity in the product bagasse stream.

NB there may also be other soluble species in a sugar solution - for example salt, NaCl(aq). Individual species may be specified in the database rather than being lumped with ''Soluble Other''. All solutes are taken into account when calculating the properties of sugar solutions and in the calculation of purity and Brix. However, the split of the solutes for species other than the four listed above will be the same as that for sucrose (e.g. if 40% of the sucrose mass goes to juice, then 40% of the NaCl(aq) mass would go to juice). The Impurities Control option only manages the split of the species ''Soluble Other''.

'''Temperature''' - The temperatures of all product streams are assumed to be the same. The product temperature is calculated via energy balance and accounts for any environmental heat loss. Any enthalpy of dilution effects are implicitly included in the energy balance through the sugar properties model.

'''Solution''' - The model solves for the split of solids, water, sucrose and impurities between juice, bagasse and vent as well as for temperature. The various splits and temperature are all coupled and are solved iteratively within the model.

'''Filling Ratio and Filling RatioM''' - The ''FillingRatioM'' relates the volumetric flow of solids into a crusher to the ''escribed'' volumetric flow of the crusher. The ''FillingRatio'' relates the volumetric flow of solids in the product bagasse stream to the ''escribed'' volumetric flow of the crusher.

A single crusher generally has filling ratios defined in terms of the bagasse flows into or out of that particular crusher. For an ''isolated crusher'', the FillingRatioM is the volumetric flow of solids into the crusher divided by the escribed volumetric flow. The Filling Ratio is the volumetric flow of solids in the product bagasse stream (or feed flow in times separation efficiency) divided by the escribed volumetric flow of the crusher. The FillingRatio and FillingRatioM are related by the separation efficiency.

*<math> FillingRatioM = \left( \; \frac{\text{Volumetric Solids Flow to Crusher} \; }{\text{Escribed volumetric flow}} \; \right) </math>

*<math> FillingRatio = \left( \; \frac{\text{Volumetric Solids Flow to Product Bagasse} \quad}{\text{Escribed volumetric flow} \;} \right) </math>

*<math> FillingRatio = \left( \; FillingRatioM \times \text{Separation Efficiency} \; \right) </math>

For a crusher operating in a milling train with two or more crushers, the filling ratio may be defined ''relative'' to the flow of bagasse into the first crusher. Thus, for a crusher in a milling train that is ''referenced'' to a feed stream, the ''FillingRatioM'' is the reference volumetric flow of solids (usually the feed into the first crusher) divided by the escribed volumetric flow of the crusher.

*<math> FillingRatioM = \left( \frac{\text{Reference Volumetric Flow of Solids} \quad}{\text{Escribed Volumetric Flow of Crusher} \quad}\right) </math>

*<math> FillingRatio = \left(\frac{\text{Volumetric Solids Flow to Product Bagasse} \quad}{\text{Escribed volumetric flow} \quad}\right) </math>

And the ''FillingRatio'' and ''FillingRatioM'' are related by the reference and the product bagasse solids volumetric flows.

*<math> FillingRatio = \left(\frac{FillingRatioM \times \text{Volumetric Solids Flow to Product Bagasse} \quad} {\text{Reference Volumetric Flow of Solids} \quad}\right) </math>

=== Environmental Heat Exchange Options ===

The crusher unit may lose heat to the environment. All input streams are assumed to mix and come to thermal equilibrium. All of the output streams are assumed to be at the same temperature.

The heat loss options are set from a drop down list and include;

# None - No Heat Exchange occurs.
# FixedLoss - Heat Flow to the Environment is specified by the user.
# Ambient - A Heat Loss Constant is specified and heat loss is calculated as heat loss constant times the temperature difference between the product stream and ambient temperatures, Qloss = Constant * (Tprod - Tamb).
# Set_Tprod - The product stream is set to a User Specified Temperature

The Heat Flow is displayed for all options and heat flow ''from'' the crusher ''to'' the environment is ''positive'' in sign.

NB If a negative heat flow is reported, it indicates heat flow to the crusher from the environment for example if the product temperature is set higher than the input temperature.

=== Evaporation Loss Options ===

There may be significant evaporation from a sugar crusher when hot water is used for inhibition. The crusher unit operation has an option to allow water evaporation. The evaporation loss rate, ''EvapLossQm'', may be entered and this quantity of water will be split of from the mixed feed stream to the unit and turned to vapour. It will flow out through the vent (along with any other vapours that enter the unit). The temperature of the vapour stream will be the same as the product bagasse and juice streams. The latent heat of vaporisation is taken into account in the calculation of the product temperature. An estimate of this energy is displayed when there a non-zero evaporation loss is entered.

== Flow Chart ==

[[Image:Sugar Crusher Flow Diagram .jpg ]]

== Data Section ==

=== Sugar Crusher Access Page ===

'''Unit Type: SugarCrusher''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
==== Requirements ====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| ShowQFeed|| Tickbox || Optional display of all input material as one mixed stream (including all feed and imbibition streams).
|-
| TackStatus|| Tickbox || Optional display to display warnings.
|-
| font style="background: #ebebeb" colspan="3" | '''Environmental Heat Loss'''
|-
| valign="top" rowspan="4" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| SetTprod|| Product temperature is user input.
|-
| EnvLossRqd|| Input || The Required Environmental Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| EnvLossCoeff|| Input || The Environmental Heat Loss Rate Coefficient(kW/K) - This is only visible if the Ambient Method is selected.
|-
| FixedProductT || Input || The Required Product Temperature - This is only visible if the SetTprod Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' crusher ''to'' environment.).
|-
| font style="background: #ebebeb" colspan="3" | '''Evaporation Loss'''
|-
| EvapLossQm|| Input || User specified evaporation rate.
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporisation).
|-
| font style="background: #ebebeb" colspan="3" | '''Use Reference Stream'''
|-
| On || Tickbox || Tickbox to set the use reference stream option on or off.
|-
| StreamTag|| Input|| The name of the stream to use for reference calculations (this would typically be the feed bagasse stream into the first crusher in a milling train).
|-
| RefQv||font style="background: #ebebeb" | Display || Volumetric flow of the reference stream solids flow (for Filling Ratio Calculations).
|-
| RefPurity||font style="background: #ebebeb" | Display || Purity of the reference stream (for purity calculations).
|-
| RefBrix||font style="background: #ebebeb" | Display || Brix mass flow of the reference stream (for extraction calculations).
|-
| colspan="3" font style="background: #ebebeb" |

==== Imbibition Efficiency ====

|-
| ImbibitionCoeff|| Input || Imbibition Coefficient, Ic (%). Allowable Input Range is 1% to 200%.
|-
|FeedBrix ||font style="background: #ebebeb"| Display || Brix fraction of Cane/Bagasse Feed Stream (includes all feed streams summed into one stream).
|-
|ImbBrix||font style="background: #ebebeb"| Display || Brix fraction of Imbibition Stream (includes all imbibition streams summed into one stream).
|-
|TheoBrix||font style="background: #ebebeb"| Display || Theoretical Massecuite Brix fraction if all input streams are perfectly mixed.
|-
|JuiceBrix||font style="background: #ebebeb"| Display || Actual Juice Massecuite Brix fraction.
|-
|BagBrix||font style="background: #ebebeb"| Display || Actual Delivery Bagasse Massecuite Brix fraction.
|-
|TheoBagBrixQm||font style="background: #ebebeb"| Display || Theoretical Delivery Bagasse Brix Mass Flow.
|-
|TargetBagBrixQm||font style="background: #ebebeb"| Display || Target Delivery Bagasse Brix Mass Flow based on feed flows and input parameters.
|-
|BagasseBrixQm||font style="background: #ebebeb"| Display || Actual Delivery Bagasse Brix Mass Flow. This may be different than the target Brix flow if the model is unable to achieve the flow with the given feed and user inputs. A warning is displayed if any constraints are not met.
|-
| colspan="3" font style="background: #ebebeb" |

==== Mill Operation ====
Controls liquid flow to product Bagasse stream.
|-
|FillingRatioM|| Input || Filling RatioM, Filling Ratio is the total volumetric flow of solids divided by the escribed volumetric flow for a single mill referenced to itself. For a mill with another reference stream, the FillingRatioM is the is the reference stream solids volumetric flow divided by the escribed volumetric flow of the mill.
|-
|FillingRatio||font style="background: #ebebeb"| Display || Filling Ratio - solids volumetric flow divided by the escribed volumetric flow. For a single mill (referenced to itself), FillingRatio = FillingRatioM
|-
|ReAbsorptionFac|| Input || Re-absorption Factor, K. Allowable Input Range is (FillingRatio + 0.01) to 10.0 (NB re-absorption factor must be larger than the filling ratio).
|-
|RatioVjVb||font style="background: #ebebeb"| Display || Required Volumetric Flow Ratio of Juice to Solids.
|-
|Escribedvolume||font style="background: #ebebeb"| Display || Volumetric Flow - width of rolls X work opening X surface speed of rolls.
|-
|TotalSolidsQv||font style="background: #ebebeb"| Display || Total Volumetric Flow of Solids to the Crusher - this is typically fibre and mud.
|-
|BagasseSolQv||font style="background: #ebebeb"| Display || Volumetric Flow of Solids to Delivery Bagasse Stream.
|-
|TheoBagLiqQv ||font style="background: #ebebeb"| Display || Theoretical Liquid Volume Flow Required.
|-
|BagasseLiqQv ||font style="background: #ebebeb"| Display || Actual Liquid Volume Flow to Delivery Bagasse Stream. A warning will be displayed if the model is unable to achieve the required volumetric flow rate.
|-
| colspan="3" font style="background: #ebebeb" |

==== Solids ====
Display Solids Concentrations and Mass Flows.
|-
| SepEfficiency|| Input || The Required Solids Separation Efficiency. This specifies the mass fraction of total solids input reporting to the delivery bagasse stream. Allowable Input Range is 10% to 100%.
|-
|JuiceSolids||font style="background: #ebebeb"| Display || Mass Percentage Solids Concentration (wt/wt) in product Juice stream.
|-
|BagasseSolids||font style="background: #ebebeb"| Display || Mass Percentage Solids Concentration (wt/wt) in product Bagasse stream.
|-
|JuiceSolConc25||font style="background: #ebebeb"| Display || Solids Concentration (wt/vol) in product Juice stream.
|-
|BagasseSolConc25||font style="background: #ebebeb"| Display || Solids Concentration (wt/vol) in product Bagasse stream.
|-
|SolidsJuiceQm||font style="background: #ebebeb"| Display || Solids Mass Flow in product Juice stream.
|-
|SolidsBagasseQm||font style="background: #ebebeb"| Display || Solids Mass Flow in product Bagasse stream.
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Crusher | Group=Sugar }}

Sugar Crusher

2025-08-08T16:07:10Z

John.McFeaters: /* Mill Operation */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=3}}
----
{{TOC}}
== General Description ==

The sugar crusher unit operation is available with the Sugar add-on.

The sugar crusher receives shredded cane (or bagasse from an upstream mill) and passes it through rolls to squeeze juice out of it. There may be an optional imbibition streams added to help wash out sucrose rich juice. There is a product juice stream, a delivery (or product) bagasse stream and a vent stream exiting the crusher.

All streams entering the crusher are assumed to mix perfectly and then the flow of solids, sucrose and impurities are split between juice, bagasse and vent to meet the specified operating parameters.

Solids are split between the juice and delivery bagasse streams according to the user specified separation efficiency.

Water and various solutes may be split in different relative proportions to the juice and bagasse streams to allow the product streams to have different Brix, overall purity and specific impurities ratios. The splits are calculated to satisfy the user specified ''Imbibition Coefficient, Ic'' and when the optional ''Purity Control'' is selected a user specified purity ratio. The feed and product streams in sugar crusher would typically use the [[Sugar Species Model]].

The volumetric flow of liquid going to the delivery bagasse stream is determined by the volumetric flow of solids to the bagasse stream and the user specified ''Filling Ratio, C'' and ''Re-absorption Factor, K''.

The crusher model includes optional heat loss to the environment and there are several different heat loss models available. The crusher also includes the option to specify evaporation rate from it
and this is included in the energy balance.

Any vapours in the input streams or from evaporation are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams and there is no vent connected.

The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant Model - Environment]]).

The crusher has the option to use a ''user specified reference stream''. Data from this stream may then be used for doing purity, extraction and volumetric flow calculations relative to the reference stream. Typically the reference stream would be the shredded cane going into the first crusher in a milling train.

== Inputs and Outputs ==

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max''' ||  
|-
| FeedBag || Required || In || 1 || 1 || Feed Bagasse to the Crusher - shredded cane or bagasse from a previous mill stage.
|-
| Imbibition || Optional || In || 0 || 5 || Optional Imbibition Streams.
|-
| Juice || Required || Out || 1 || 1 || Primarily liquid squeezed from the bagasse - may have some solids content.
|-
| Bagasse|| Required || Out || 1 || 1 || Delivery (or Product) Bagasse - most of the input solids, with some liquid.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapours - not required if there are no vapours present.
|-
|}

NB Aqueous Sucrose must be present in the Feed Bagasse stream or an error will be reported.

== Behavior when Model is OFF ==

The sugar crusher unit may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off it is basically bypassed and the following behavior occurs:
* All material in streams connected to ''Feed'' will flow straight through to the product Bagasse stream with no changes or heat exchange.
* All material in streams connected to ''Imbibition'' will flow through to the product Juice stream with no changes or heat exchange.
* There will be no heat transfer to the environment.

NB any gases in either feed or imbibition streams will remain with those streams when the unit is off.

== Model Theory ==

The input streams to the crusher are the ''Feed Bagasse'' stream which is the shredded sugar cane or bagasse from a previous mill stage and the ''Imbibition'' stream which is usually lower Brix juice from a downstream mill stage or water. All of the input and output streams are a mixture of solids and liquids. The solids are primarily plant fiber but may contain mud and other material. The liquids are primarily sucrose-water solutions with some aqueous impurities. NB Brix refers to ''all'' solutes in the liquid phase - or basically everything except water.

The model allows for multiple imbibition streams. All the feed and imbibition streams are assumed to mix perfectly in the crusher. The flows of solids, Brix and water must then be split to satisfy the user specified operating parameters.

The output streams are ''Juice'' which is primarily liquid although may have some solids, ''Bagasse'' which is most of the fiber and some liquid and a ''Vent'' for gases. These are shown in the flow chart below.

'''Gases''' - Any gases present in any of the input streams are split off and go to the vent stream. If there is no vent attached, the gases are sent out with the juice stream and a warning is displayed that there are gases present, but no vent.

'''Solids''' - Solids from mixed input stream split according to the user specified ''Separation Coefficient'' (which is the mass fraction of solids reporting to bagasse). Generally, most of the solids report to the bagasse stream and any remaining solids report to the juice stream.

'''Liquids''' - The overall split of liquid between juice and bagasse streams is calculated to give the required volumetric flow of juice going to the product bagasse stream. This flow is determined by the volumetric flow of solids, the ''Filling Ratio'' and the ''Re-absorption Factor''. The required volumetric flow ratio of juice to solids is given by; Vj/Vs = (Re-absorption Factor - Filling Ratio) / Filling Ratio. (NB the mass of liquid going to bagasse depends on the liquid density).

The individual split of water and Brix is based on the ''Imbibition Coefficient, Ic'' which is a measure of actual Brix extraction to theoretical Brix extraction. It is possible to have an imbibition coefficient that is greater or less than than one and the Brix of the juice and bagasse streams may be different. When the imbibition coefficient is one the Brix of the juice and bagasse streams are equal, when it is less than one, the bagasse Brix is higher than the juice Brix and when it is greater than one the juice Brix is higher then the bagasse Brix. The SysCAD sugar crusher model splits water and Brix to match the imbibition coefficient with the constraint that the required volume flow to delivery bagasse must be met (and also that various constraints on impurities are met so that the ratio of sucrose to impurities is may also be adjusted between the bagasse and juice streams - see below).

A theoretical Brix is calculated assuming a perfect mixture of all the streams coming in and the imbibition coefficient is the actual Brix mass flow to juice divided by the theoretical Brix mass flow to juice.

*<math> \text{Imbibition Coefficient, Ic} = \frac {(\text{Brix into Crusher} \quad - \quad \text{Brix in Delivery Bagasse} \;)}{(\text{Brix into Crusher} \quad- \quad \text{Theoretical Brix in Delivery Bagasse} \;)}</math>

'''Impurities''' - The impurities include ''all'' solutes other than sucrose. The sugar crusher model identifies four specific impurities that normally derived from the analysis of bagasse. These species are managed individually in the crusher model and must be present in the species data base (although their mass flows may be set to zero). The species and the control of them is as follows;

# Reducing Sugars - the ratio of reducing sugars to Pol is assumed to be constant between the feed bagasse and product bagasse.
# Soluble Ash - the ratio of Soluble Ash to Brix is assumed to be constant between the feed bagasse and the product bagasse.
# Soluble Protein - the ratio of Soluble Protein to Brix is assumed to be constant between the feed bagasse and the product bagasse.
# Soluble Other - Soluble Other includes the other soluble species found in sugar cane and not specifically identified as a Reducing Sugar, Ash or Protein. The concentration of Soluble Other may be varied in the model in order to control the sugar purity in the product bagasse stream.

NB there may also be other soluble species in a sugar solution - for example salt, NaCl(aq). Individual species may be specified in the database rather than being lumped with ''Soluble Other''. All solutes are taken into account when calculating the properties of sugar solutions and in the calculation of purity and Brix. However, the split of the solutes for species other than the four listed above will be the same as that for sucrose (e.g. if 40% of the sucrose mass goes to juice, then 40% of the NaCl(aq) mass would go to juice). The Impurities Control option only manages the split of the species ''Soluble Other''.

'''Temperature''' - The temperatures of all product streams are assumed to be the same. The product temperature is calculated via energy balance and accounts for any environmental heat loss. Any enthalpy of dilution effects are implicitly included in the energy balance through the sugar properties model.

'''Solution''' - The model solves for the split of solids, water, sucrose and impurities between juice, bagasse and vent as well as for temperature. The various splits and temperature are all coupled and are solved iteratively within the model.

'''Filling Ratio and Filling RatioM''' - The ''FillingRatioM'' relates the volumetric flow of solids into a crusher to the ''escribed'' volumetric flow of the crusher. The ''FillingRatio'' relates the volumetric flow of solids in the product bagasse stream to the ''escribed'' volumetric flow of the crusher.

A single crusher generally has filling ratios defined in terms of the bagasse flows into or out of that particular crusher. For an ''isolated crusher'', the FillingRatioM is the volumetric flow of solids into the crusher divided by the escribed volumetric flow. The Filling Ratio is the volumetric flow of solids in the product bagasse stream (or feed flow in times separation efficiency) divided by the escribed volumetric flow of the crusher. The FillingRatio and FillingRatioM are related by the separation efficiency.

*<math> FillingRatioM = \left( \; \frac{\text{Volumetric Solids Flow to Crusher} \; }{\text{Escribed volumetric flow}} \; \right) </math>

*<math> FillingRatio = \left( \; \frac{\text{Volumetric Solids Flow to Product Bagasse} \quad}{\text{Escribed volumetric flow} \;} \right) </math>

*<math> FillingRatio = \left( \; FillingRatioM \times \text{Separation Efficiency} \; \right) </math>

For a crusher operating in a milling train with two or more crushers, the filling ratio may be defined ''relative'' to the flow of bagasse into the first crusher. Thus, for a crusher in a milling train that is ''referenced'' to a feed stream, the ''FillingRatioM'' is the reference volumetric flow of solids (usually the feed into the first crusher) divided by the escribed volumetric flow of the crusher.

*<math> FillingRatioM = \left( \frac{\text{Reference Volumetric Flow of Solids} \quad}{\text{Escribed Volumetric Flow of Crusher} \quad}\right) </math>

*<math> FillingRatio = \left(\frac{\text{Volumetric Solids Flow to Product Bagasse} \quad}{\text{Escribed volumetric flow} \quad}\right) </math>

And the ''FillingRatio'' and ''FillingRatioM'' are related by the reference and the product bagasse solids volumetric flows.

*<math> FillingRatio = \left(\frac{FillingRatioM \times \text{Volumetric Solids Flow to Product Bagasse} \quad} {\text{Reference Volumetric Flow of Solids} \quad}\right) </math>

=== Environmental Heat Exchange Options ===

The crusher unit may lose heat to the environment. All input streams are assumed to mix and come to thermal equilibrium. All of the output streams are assumed to be at the same temperature.

The heat loss options are set from a drop down list and include;

# None - No Heat Exchange occurs.
# FixedLoss - Heat Flow to the Environment is specified by the user.
# Ambient - A Heat Loss Constant is specified and heat loss is calculated as heat loss constant times the temperature difference between the product stream and ambient temperatures, Qloss = Constant * (Tprod - Tamb).
# Set_Tprod - The product stream is set to a User Specified Temperature

The Heat Flow is displayed for all options and heat flow ''from'' the crusher ''to'' the environment is ''positive'' in sign.

NB If a negative heat flow is reported, it indicates heat flow to the crusher from the environment for example if the product temperature is set higher than the input temperature.

=== Evaporation Loss Options ===

There may be significant evaporation from a sugar crusher when hot water is used for inhibition. The crusher unit operation has an option to allow water evaporation. The evaporation loss rate, ''EvapLossQm'', may be entered and this quantity of water will be split of from the mixed feed stream to the unit and turned to vapour. It will flow out through the vent (along with any other vapours that enter the unit). The temperature of the vapour stream will be the same as the product bagasse and juice streams. The latent heat of vaporisation is taken into account in the calculation of the product temperature. An estimate of this energy is displayed when there a non-zero evaporation loss is entered.

== Flow Chart ==

[[Image:Sugar Crusher Flow Diagram .jpg ]]

== Data Section ==

=== Sugar Crusher Access Page ===

'''Unit Type: SugarCrusher''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
==== Requirements ====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| ShowQFeed|| Tickbox || Optional display of all input material as one mixed stream (including all feed and imbibition streams).
|-
| TackStatus|| Tickbox || Optional display to display warnings.
|-
| font style="background: #ebebeb" colspan="3" | '''Environmental Heat Loss'''
|-
| valign="top" rowspan="4" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| SetTprod|| Product temperature is user input.
|-
| EnvLossRqd|| Input || The Required Environmental Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| EnvLossCoeff|| Input || The Environmental Heat Loss Rate Coefficient(kW/K) - This is only visible if the Ambient Method is selected.
|-
| FixedProductT || Input || The Required Product Temperature - This is only visible if the SetTprod Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' crusher ''to'' environment.).
|-
| font style="background: #ebebeb" colspan="3" | '''Evaporation Loss'''
|-
| EvapLossQm|| Input || User specified evaporation rate.
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporisation).
|-
| font style="background: #ebebeb" colspan="3" | '''Use Reference Stream'''
|-
| On || Tickbox || Tickbox to set the use reference stream option on or off.
|-
| StreamTag|| Input|| The name of the stream to use for reference calculations (this would typically be the feed bagasse stream into the first crusher in a milling train).
|-
| RefQv||font style="background: #ebebeb" | Display || Volumetric flow of the reference stream solids flow (for Filling Ratio Calculations).
|-
| RefPurity||font style="background: #ebebeb" | Display || Purity of the reference stream (for purity calculations).
|-
| RefBrix||font style="background: #ebebeb" | Display || Brix mass flow of the reference stream (for extraction calculations).
|-
| colspan="3" font style="background: #ebebeb" |

==== Imbibition Efficiency ====

|-
| ImbibitionCoeff|| Input || Imbibition Coefficient, Ic (%). Allowable Input Range is 1% to 200%.
|-
|FeedBrix ||font style="background: #ebebeb"| Display || Brix fraction of Cane/Bagasse Feed Stream (includes all feed streams summed into one stream).
|-
|ImbBrix||font style="background: #ebebeb"| Display || Brix fraction of Imbibition Stream (includes all imbibition streams summed into one stream).
|-
|TheoBrix||font style="background: #ebebeb"| Display || Theoretical Massecuite Brix fraction if all input streams are perfectly mixed.
|-
|JuiceBrix||font style="background: #ebebeb"| Display || Actual Juice Massecuite Brix fraction.
|-
|BagBrix||font style="background: #ebebeb"| Display || Actual Delivery Bagasse Massecuite Brix fraction.
|-
|TheoBagBrixQm||font style="background: #ebebeb"| Display || Theoretical Delivery Bagasse Brix Mass Flow.
|-
|TargetBagBrixQm||font style="background: #ebebeb"| Display || Target Delivery Bagasse Brix Mass Flow based on feed flows and input parameters.
|-
|BagasseBrixQm||font style="background: #ebebeb"| Display || Actual Delivery Bagasse Brix Mass Flow. This may be different than the target Brix flow if the model is unable to achieve the flow with the given feed and user inputs. A warning is displayed if any constraints are not met.
|-
| colspan="3" font style="background: #ebebeb" |

==== Mill Operation ====
Controls liquid flow to product Bagasse stream.
|-
|FillingRatioM|| Input || Filling RatioM, Filling Ratio is the total volumetric flow of solids divided by the escribed volumetric flow for a single mill referenced to itself. For a mill with another reference stream, the FillingRatioM is the is the reference stream solids volumetric flow divided by the escribed volumetric flow of the mill.
|-
|FillingRatio||font style="background: #ebebeb"| Display || Filling Ratio - solids volumetric flow divided by the escribed volumetric flow. For a single mill (referenced to itself), FillingRatio = FillingRatioM
|-
|ReAbsorptionFac|| Input || Re-absorption Factor, K. Allowable Input Range is (FillingRatio + 0.01) to 10.0 (NB re-absorption factor must be larger than the filling ratio).
|-
|RatioVjVb||font style="background: #ebebeb"| Display || Required Volumetric Flow Ratio of Juice to Solids.
|-
|Escribedvolume||font style="background: #ebebeb"| Display || Volumetric Flow - width of rolls X work opening X surface speed of rolls.
|-
|TotalSolidsQv||font style="background: #ebebeb"| Display || Total Volumetric Flow of Solids to the Crusher.
|-
|BagasseSolQv||font style="background: #ebebeb"| Display || Volumetric Flow of Solids to Delivery Bagasse Stream.
|-
|TheoBagLiqQv ||font style="background: #ebebeb"| Display || Theoretical Liquid Volume Flow Required.
|-
|BagasseLiqQv ||font style="background: #ebebeb"| Display || Actual Liquid Volume Flow to Delivery Bagasse Stream. A warning will be displayed if the model is unable to achieve the required volumetric flow rate.
|-
| colspan="3" font style="background: #ebebeb" |

==== Solids ====
Display Solids Concentrations and Mass Flows.
|-
| SepEfficiency|| Input || The Required Solids Separation Efficiency. This specifies the mass fraction of total solids input reporting to the delivery bagasse stream. Allowable Input Range is 10% to 100%.
|-
|JuiceSolids||font style="background: #ebebeb"| Display || Mass Percentage Solids Concentration (wt/wt) in product Juice stream.
|-
|BagasseSolids||font style="background: #ebebeb"| Display || Mass Percentage Solids Concentration (wt/wt) in product Bagasse stream.
|-
|JuiceSolConc25||font style="background: #ebebeb"| Display || Solids Concentration (wt/vol) in product Juice stream.
|-
|BagasseSolConc25||font style="background: #ebebeb"| Display || Solids Concentration (wt/vol) in product Bagasse stream.
|-
|SolidsJuiceQm||font style="background: #ebebeb"| Display || Solids Mass Flow in product Juice stream.
|-
|SolidsBagasseQm||font style="background: #ebebeb"| Display || Solids Mass Flow in product Bagasse stream.
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Crusher | Group=Sugar }}

Sugar Crusher

2025-08-08T16:04:43Z

John.McFeaters: /* Mill Operation */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=3}}
----
{{TOC}}
== General Description ==

The sugar crusher unit operation is available with the Sugar add-on.

The sugar crusher receives shredded cane (or bagasse from an upstream mill) and passes it through rolls to squeeze juice out of it. There may be an optional imbibition streams added to help wash out sucrose rich juice. There is a product juice stream, a delivery (or product) bagasse stream and a vent stream exiting the crusher.

All streams entering the crusher are assumed to mix perfectly and then the flow of solids, sucrose and impurities are split between juice, bagasse and vent to meet the specified operating parameters.

Solids are split between the juice and delivery bagasse streams according to the user specified separation efficiency.

Water and various solutes may be split in different relative proportions to the juice and bagasse streams to allow the product streams to have different Brix, overall purity and specific impurities ratios. The splits are calculated to satisfy the user specified ''Imbibition Coefficient, Ic'' and when the optional ''Purity Control'' is selected a user specified purity ratio. The feed and product streams in sugar crusher would typically use the [[Sugar Species Model]].

The volumetric flow of liquid going to the delivery bagasse stream is determined by the volumetric flow of solids to the bagasse stream and the user specified ''Filling Ratio, C'' and ''Re-absorption Factor, K''.

The crusher model includes optional heat loss to the environment and there are several different heat loss models available. The crusher also includes the option to specify evaporation rate from it
and this is included in the energy balance.

Any vapours in the input streams or from evaporation are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams and there is no vent connected.

The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant Model - Environment]]).

The crusher has the option to use a ''user specified reference stream''. Data from this stream may then be used for doing purity, extraction and volumetric flow calculations relative to the reference stream. Typically the reference stream would be the shredded cane going into the first crusher in a milling train.

== Inputs and Outputs ==

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max''' ||  
|-
| FeedBag || Required || In || 1 || 1 || Feed Bagasse to the Crusher - shredded cane or bagasse from a previous mill stage.
|-
| Imbibition || Optional || In || 0 || 5 || Optional Imbibition Streams.
|-
| Juice || Required || Out || 1 || 1 || Primarily liquid squeezed from the bagasse - may have some solids content.
|-
| Bagasse|| Required || Out || 1 || 1 || Delivery (or Product) Bagasse - most of the input solids, with some liquid.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapours - not required if there are no vapours present.
|-
|}

NB Aqueous Sucrose must be present in the Feed Bagasse stream or an error will be reported.

== Behavior when Model is OFF ==

The sugar crusher unit may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off it is basically bypassed and the following behavior occurs:
* All material in streams connected to ''Feed'' will flow straight through to the product Bagasse stream with no changes or heat exchange.
* All material in streams connected to ''Imbibition'' will flow through to the product Juice stream with no changes or heat exchange.
* There will be no heat transfer to the environment.

NB any gases in either feed or imbibition streams will remain with those streams when the unit is off.

== Model Theory ==

The input streams to the crusher are the ''Feed Bagasse'' stream which is the shredded sugar cane or bagasse from a previous mill stage and the ''Imbibition'' stream which is usually lower Brix juice from a downstream mill stage or water. All of the input and output streams are a mixture of solids and liquids. The solids are primarily plant fiber but may contain mud and other material. The liquids are primarily sucrose-water solutions with some aqueous impurities. NB Brix refers to ''all'' solutes in the liquid phase - or basically everything except water.

The model allows for multiple imbibition streams. All the feed and imbibition streams are assumed to mix perfectly in the crusher. The flows of solids, Brix and water must then be split to satisfy the user specified operating parameters.

The output streams are ''Juice'' which is primarily liquid although may have some solids, ''Bagasse'' which is most of the fiber and some liquid and a ''Vent'' for gases. These are shown in the flow chart below.

'''Gases''' - Any gases present in any of the input streams are split off and go to the vent stream. If there is no vent attached, the gases are sent out with the juice stream and a warning is displayed that there are gases present, but no vent.

'''Solids''' - Solids from mixed input stream split according to the user specified ''Separation Coefficient'' (which is the mass fraction of solids reporting to bagasse). Generally, most of the solids report to the bagasse stream and any remaining solids report to the juice stream.

'''Liquids''' - The overall split of liquid between juice and bagasse streams is calculated to give the required volumetric flow of juice going to the product bagasse stream. This flow is determined by the volumetric flow of solids, the ''Filling Ratio'' and the ''Re-absorption Factor''. The required volumetric flow ratio of juice to solids is given by; Vj/Vs = (Re-absorption Factor - Filling Ratio) / Filling Ratio. (NB the mass of liquid going to bagasse depends on the liquid density).

The individual split of water and Brix is based on the ''Imbibition Coefficient, Ic'' which is a measure of actual Brix extraction to theoretical Brix extraction. It is possible to have an imbibition coefficient that is greater or less than than one and the Brix of the juice and bagasse streams may be different. When the imbibition coefficient is one the Brix of the juice and bagasse streams are equal, when it is less than one, the bagasse Brix is higher than the juice Brix and when it is greater than one the juice Brix is higher then the bagasse Brix. The SysCAD sugar crusher model splits water and Brix to match the imbibition coefficient with the constraint that the required volume flow to delivery bagasse must be met (and also that various constraints on impurities are met so that the ratio of sucrose to impurities is may also be adjusted between the bagasse and juice streams - see below).

A theoretical Brix is calculated assuming a perfect mixture of all the streams coming in and the imbibition coefficient is the actual Brix mass flow to juice divided by the theoretical Brix mass flow to juice.

*<math> \text{Imbibition Coefficient, Ic} = \frac {(\text{Brix into Crusher} \quad - \quad \text{Brix in Delivery Bagasse} \;)}{(\text{Brix into Crusher} \quad- \quad \text{Theoretical Brix in Delivery Bagasse} \;)}</math>

'''Impurities''' - The impurities include ''all'' solutes other than sucrose. The sugar crusher model identifies four specific impurities that normally derived from the analysis of bagasse. These species are managed individually in the crusher model and must be present in the species data base (although their mass flows may be set to zero). The species and the control of them is as follows;

# Reducing Sugars - the ratio of reducing sugars to Pol is assumed to be constant between the feed bagasse and product bagasse.
# Soluble Ash - the ratio of Soluble Ash to Brix is assumed to be constant between the feed bagasse and the product bagasse.
# Soluble Protein - the ratio of Soluble Protein to Brix is assumed to be constant between the feed bagasse and the product bagasse.
# Soluble Other - Soluble Other includes the other soluble species found in sugar cane and not specifically identified as a Reducing Sugar, Ash or Protein. The concentration of Soluble Other may be varied in the model in order to control the sugar purity in the product bagasse stream.

NB there may also be other soluble species in a sugar solution - for example salt, NaCl(aq). Individual species may be specified in the database rather than being lumped with ''Soluble Other''. All solutes are taken into account when calculating the properties of sugar solutions and in the calculation of purity and Brix. However, the split of the solutes for species other than the four listed above will be the same as that for sucrose (e.g. if 40% of the sucrose mass goes to juice, then 40% of the NaCl(aq) mass would go to juice). The Impurities Control option only manages the split of the species ''Soluble Other''.

'''Temperature''' - The temperatures of all product streams are assumed to be the same. The product temperature is calculated via energy balance and accounts for any environmental heat loss. Any enthalpy of dilution effects are implicitly included in the energy balance through the sugar properties model.

'''Solution''' - The model solves for the split of solids, water, sucrose and impurities between juice, bagasse and vent as well as for temperature. The various splits and temperature are all coupled and are solved iteratively within the model.

'''Filling Ratio and Filling RatioM''' - The ''FillingRatioM'' relates the volumetric flow of solids into a crusher to the ''escribed'' volumetric flow of the crusher. The ''FillingRatio'' relates the volumetric flow of solids in the product bagasse stream to the ''escribed'' volumetric flow of the crusher.

A single crusher generally has filling ratios defined in terms of the bagasse flows into or out of that particular crusher. For an ''isolated crusher'', the FillingRatioM is the volumetric flow of solids into the crusher divided by the escribed volumetric flow. The Filling Ratio is the volumetric flow of solids in the product bagasse stream (or feed flow in times separation efficiency) divided by the escribed volumetric flow of the crusher. The FillingRatio and FillingRatioM are related by the separation efficiency.

*<math> FillingRatioM = \left( \; \frac{\text{Volumetric Solids Flow to Crusher} \; }{\text{Escribed volumetric flow}} \; \right) </math>

*<math> FillingRatio = \left( \; \frac{\text{Volumetric Solids Flow to Product Bagasse} \quad}{\text{Escribed volumetric flow} \;} \right) </math>

*<math> FillingRatio = \left( \; FillingRatioM \times \text{Separation Efficiency} \; \right) </math>

For a crusher operating in a milling train with two or more crushers, the filling ratio may be defined ''relative'' to the flow of bagasse into the first crusher. Thus, for a crusher in a milling train that is ''referenced'' to a feed stream, the ''FillingRatioM'' is the reference volumetric flow of solids (usually the feed into the first crusher) divided by the escribed volumetric flow of the crusher.

*<math> FillingRatioM = \left( \frac{\text{Reference Volumetric Flow of Solids} \quad}{\text{Escribed Volumetric Flow of Crusher} \quad}\right) </math>

*<math> FillingRatio = \left(\frac{\text{Volumetric Solids Flow to Product Bagasse} \quad}{\text{Escribed volumetric flow} \quad}\right) </math>

And the ''FillingRatio'' and ''FillingRatioM'' are related by the reference and the product bagasse solids volumetric flows.

*<math> FillingRatio = \left(\frac{FillingRatioM \times \text{Volumetric Solids Flow to Product Bagasse} \quad} {\text{Reference Volumetric Flow of Solids} \quad}\right) </math>

=== Environmental Heat Exchange Options ===

The crusher unit may lose heat to the environment. All input streams are assumed to mix and come to thermal equilibrium. All of the output streams are assumed to be at the same temperature.

The heat loss options are set from a drop down list and include;

# None - No Heat Exchange occurs.
# FixedLoss - Heat Flow to the Environment is specified by the user.
# Ambient - A Heat Loss Constant is specified and heat loss is calculated as heat loss constant times the temperature difference between the product stream and ambient temperatures, Qloss = Constant * (Tprod - Tamb).
# Set_Tprod - The product stream is set to a User Specified Temperature

The Heat Flow is displayed for all options and heat flow ''from'' the crusher ''to'' the environment is ''positive'' in sign.

NB If a negative heat flow is reported, it indicates heat flow to the crusher from the environment for example if the product temperature is set higher than the input temperature.

=== Evaporation Loss Options ===

There may be significant evaporation from a sugar crusher when hot water is used for inhibition. The crusher unit operation has an option to allow water evaporation. The evaporation loss rate, ''EvapLossQm'', may be entered and this quantity of water will be split of from the mixed feed stream to the unit and turned to vapour. It will flow out through the vent (along with any other vapours that enter the unit). The temperature of the vapour stream will be the same as the product bagasse and juice streams. The latent heat of vaporisation is taken into account in the calculation of the product temperature. An estimate of this energy is displayed when there a non-zero evaporation loss is entered.

== Flow Chart ==

[[Image:Sugar Crusher Flow Diagram .jpg ]]

== Data Section ==

=== Sugar Crusher Access Page ===

'''Unit Type: SugarCrusher''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
==== Requirements ====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| ShowQFeed|| Tickbox || Optional display of all input material as one mixed stream (including all feed and imbibition streams).
|-
| TackStatus|| Tickbox || Optional display to display warnings.
|-
| font style="background: #ebebeb" colspan="3" | '''Environmental Heat Loss'''
|-
| valign="top" rowspan="4" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| SetTprod|| Product temperature is user input.
|-
| EnvLossRqd|| Input || The Required Environmental Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| EnvLossCoeff|| Input || The Environmental Heat Loss Rate Coefficient(kW/K) - This is only visible if the Ambient Method is selected.
|-
| FixedProductT || Input || The Required Product Temperature - This is only visible if the SetTprod Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' crusher ''to'' environment.).
|-
| font style="background: #ebebeb" colspan="3" | '''Evaporation Loss'''
|-
| EvapLossQm|| Input || User specified evaporation rate.
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporisation).
|-
| font style="background: #ebebeb" colspan="3" | '''Use Reference Stream'''
|-
| On || Tickbox || Tickbox to set the use reference stream option on or off.
|-
| StreamTag|| Input|| The name of the stream to use for reference calculations (this would typically be the feed bagasse stream into the first crusher in a milling train).
|-
| RefQv||font style="background: #ebebeb" | Display || Volumetric flow of the reference stream solids flow (for Filling Ratio Calculations).
|-
| RefPurity||font style="background: #ebebeb" | Display || Purity of the reference stream (for purity calculations).
|-
| RefBrix||font style="background: #ebebeb" | Display || Brix mass flow of the reference stream (for extraction calculations).
|-
| colspan="3" font style="background: #ebebeb" |

==== Imbibition Efficiency ====

|-
| ImbibitionCoeff|| Input || Imbibition Coefficient, Ic (%). Allowable Input Range is 1% to 200%.
|-
|FeedBrix ||font style="background: #ebebeb"| Display || Brix fraction of Cane/Bagasse Feed Stream (includes all feed streams summed into one stream).
|-
|ImbBrix||font style="background: #ebebeb"| Display || Brix fraction of Imbibition Stream (includes all imbibition streams summed into one stream).
|-
|TheoBrix||font style="background: #ebebeb"| Display || Theoretical Massecuite Brix fraction if all input streams are perfectly mixed.
|-
|JuiceBrix||font style="background: #ebebeb"| Display || Actual Juice Massecuite Brix fraction.
|-
|BagBrix||font style="background: #ebebeb"| Display || Actual Delivery Bagasse Massecuite Brix fraction.
|-
|TheoBagBrixQm||font style="background: #ebebeb"| Display || Theoretical Delivery Bagasse Brix Mass Flow.
|-
|TargetBagBrixQm||font style="background: #ebebeb"| Display || Target Delivery Bagasse Brix Mass Flow based on feed flows and input parameters.
|-
|BagasseBrixQm||font style="background: #ebebeb"| Display || Actual Delivery Bagasse Brix Mass Flow. This may be different than the target Brix flow if the model is unable to achieve the flow with the given feed and user inputs. A warning is displayed if any constraints are not met.
|-
| colspan="3" font style="background: #ebebeb" |

==== Mill Operation ====
Controls liquid flow to product Bagasse stream.
|-
|FillingRatioM|| Input || Filling RatioM, Filling Ratio is the total volumetric flow of solids divided by the escribed volumetric flow for a single mill referenced to itself. For a mill with another reference stream, the FillingRatioM is the is the reference stream solids volumetric flow divided by the escribed volumetric flow of the mill.
|-
|FillingRatio||font style="background: #ebebeb"| Display || Filling Ratio - solids volumetric flow divided by the escribed volumetric flow. For a single mill (referenced to itself), FillingRatio = FillingRatioM
|-
|ReAbsorptionFac|| Input || Re-absorption Factor, K. Allowable Input Range is (FillingRatio + 0.01) to 10.0 (NB re-absorption factor must be larger than the filling ratio).
|-
|RatioVjVb||font style="background: #ebebeb"| Display || Required Volumetric Flow Ratio of Juice to Solids.
|-
|Escribedvolume||font style="background: #ebebeb"| Display || Volumetric Flow - width of rolls times work opening times surface speed of rolls.
|-
|TotalSolidsQv||font style="background: #ebebeb"| Display || Total Volumetric Flow of Solids to the Crusher.
|-
|BagasseSolQv||font style="background: #ebebeb"| Display || Volumetric Flow of Solids to Delivery Bagasse Stream.
|-
|TheoBagLiqQv ||font style="background: #ebebeb"| Display || Theoretical Liquid Volume Flow Required.
|-
|BagasseLiqQv ||font style="background: #ebebeb"| Display || Actual Liquid Volume Flow to Delivery Bagasse Stream. A warning will be displayed if the model is unable to achieve the required volumetric flow rate.
|-
| colspan="3" font style="background: #ebebeb" |

==== Solids ====
Display Solids Concentrations and Mass Flows.
|-
| SepEfficiency|| Input || The Required Solids Separation Efficiency. This specifies the mass fraction of total solids input reporting to the delivery bagasse stream. Allowable Input Range is 10% to 100%.
|-
|JuiceSolids||font style="background: #ebebeb"| Display || Mass Percentage Solids Concentration (wt/wt) in product Juice stream.
|-
|BagasseSolids||font style="background: #ebebeb"| Display || Mass Percentage Solids Concentration (wt/wt) in product Bagasse stream.
|-
|JuiceSolConc25||font style="background: #ebebeb"| Display || Solids Concentration (wt/vol) in product Juice stream.
|-
|BagasseSolConc25||font style="background: #ebebeb"| Display || Solids Concentration (wt/vol) in product Bagasse stream.
|-
|SolidsJuiceQm||font style="background: #ebebeb"| Display || Solids Mass Flow in product Juice stream.
|-
|SolidsBagasseQm||font style="background: #ebebeb"| Display || Solids Mass Flow in product Bagasse stream.
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Crusher | Group=Sugar }}

Sugar Crusher

2025-08-08T16:01:47Z

John.McFeaters: /* Mill Operation */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=3}}
----
{{TOC}}
== General Description ==

The sugar crusher unit operation is available with the Sugar add-on.

The sugar crusher receives shredded cane (or bagasse from an upstream mill) and passes it through rolls to squeeze juice out of it. There may be an optional imbibition streams added to help wash out sucrose rich juice. There is a product juice stream, a delivery (or product) bagasse stream and a vent stream exiting the crusher.

All streams entering the crusher are assumed to mix perfectly and then the flow of solids, sucrose and impurities are split between juice, bagasse and vent to meet the specified operating parameters.

Solids are split between the juice and delivery bagasse streams according to the user specified separation efficiency.

Water and various solutes may be split in different relative proportions to the juice and bagasse streams to allow the product streams to have different Brix, overall purity and specific impurities ratios. The splits are calculated to satisfy the user specified ''Imbibition Coefficient, Ic'' and when the optional ''Purity Control'' is selected a user specified purity ratio. The feed and product streams in sugar crusher would typically use the [[Sugar Species Model]].

The volumetric flow of liquid going to the delivery bagasse stream is determined by the volumetric flow of solids to the bagasse stream and the user specified ''Filling Ratio, C'' and ''Re-absorption Factor, K''.

The crusher model includes optional heat loss to the environment and there are several different heat loss models available. The crusher also includes the option to specify evaporation rate from it
and this is included in the energy balance.

Any vapours in the input streams or from evaporation are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams and there is no vent connected.

The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant Model - Environment]]).

The crusher has the option to use a ''user specified reference stream''. Data from this stream may then be used for doing purity, extraction and volumetric flow calculations relative to the reference stream. Typically the reference stream would be the shredded cane going into the first crusher in a milling train.

== Inputs and Outputs ==

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max''' ||  
|-
| FeedBag || Required || In || 1 || 1 || Feed Bagasse to the Crusher - shredded cane or bagasse from a previous mill stage.
|-
| Imbibition || Optional || In || 0 || 5 || Optional Imbibition Streams.
|-
| Juice || Required || Out || 1 || 1 || Primarily liquid squeezed from the bagasse - may have some solids content.
|-
| Bagasse|| Required || Out || 1 || 1 || Delivery (or Product) Bagasse - most of the input solids, with some liquid.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapours - not required if there are no vapours present.
|-
|}

NB Aqueous Sucrose must be present in the Feed Bagasse stream or an error will be reported.

== Behavior when Model is OFF ==

The sugar crusher unit may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off it is basically bypassed and the following behavior occurs:
* All material in streams connected to ''Feed'' will flow straight through to the product Bagasse stream with no changes or heat exchange.
* All material in streams connected to ''Imbibition'' will flow through to the product Juice stream with no changes or heat exchange.
* There will be no heat transfer to the environment.

NB any gases in either feed or imbibition streams will remain with those streams when the unit is off.

== Model Theory ==

The input streams to the crusher are the ''Feed Bagasse'' stream which is the shredded sugar cane or bagasse from a previous mill stage and the ''Imbibition'' stream which is usually lower Brix juice from a downstream mill stage or water. All of the input and output streams are a mixture of solids and liquids. The solids are primarily plant fiber but may contain mud and other material. The liquids are primarily sucrose-water solutions with some aqueous impurities. NB Brix refers to ''all'' solutes in the liquid phase - or basically everything except water.

The model allows for multiple imbibition streams. All the feed and imbibition streams are assumed to mix perfectly in the crusher. The flows of solids, Brix and water must then be split to satisfy the user specified operating parameters.

The output streams are ''Juice'' which is primarily liquid although may have some solids, ''Bagasse'' which is most of the fiber and some liquid and a ''Vent'' for gases. These are shown in the flow chart below.

'''Gases''' - Any gases present in any of the input streams are split off and go to the vent stream. If there is no vent attached, the gases are sent out with the juice stream and a warning is displayed that there are gases present, but no vent.

'''Solids''' - Solids from mixed input stream split according to the user specified ''Separation Coefficient'' (which is the mass fraction of solids reporting to bagasse). Generally, most of the solids report to the bagasse stream and any remaining solids report to the juice stream.

'''Liquids''' - The overall split of liquid between juice and bagasse streams is calculated to give the required volumetric flow of juice going to the product bagasse stream. This flow is determined by the volumetric flow of solids, the ''Filling Ratio'' and the ''Re-absorption Factor''. The required volumetric flow ratio of juice to solids is given by; Vj/Vs = (Re-absorption Factor - Filling Ratio) / Filling Ratio. (NB the mass of liquid going to bagasse depends on the liquid density).

The individual split of water and Brix is based on the ''Imbibition Coefficient, Ic'' which is a measure of actual Brix extraction to theoretical Brix extraction. It is possible to have an imbibition coefficient that is greater or less than than one and the Brix of the juice and bagasse streams may be different. When the imbibition coefficient is one the Brix of the juice and bagasse streams are equal, when it is less than one, the bagasse Brix is higher than the juice Brix and when it is greater than one the juice Brix is higher then the bagasse Brix. The SysCAD sugar crusher model splits water and Brix to match the imbibition coefficient with the constraint that the required volume flow to delivery bagasse must be met (and also that various constraints on impurities are met so that the ratio of sucrose to impurities is may also be adjusted between the bagasse and juice streams - see below).

A theoretical Brix is calculated assuming a perfect mixture of all the streams coming in and the imbibition coefficient is the actual Brix mass flow to juice divided by the theoretical Brix mass flow to juice.

*<math> \text{Imbibition Coefficient, Ic} = \frac {(\text{Brix into Crusher} \quad - \quad \text{Brix in Delivery Bagasse} \;)}{(\text{Brix into Crusher} \quad- \quad \text{Theoretical Brix in Delivery Bagasse} \;)}</math>

'''Impurities''' - The impurities include ''all'' solutes other than sucrose. The sugar crusher model identifies four specific impurities that normally derived from the analysis of bagasse. These species are managed individually in the crusher model and must be present in the species data base (although their mass flows may be set to zero). The species and the control of them is as follows;

# Reducing Sugars - the ratio of reducing sugars to Pol is assumed to be constant between the feed bagasse and product bagasse.
# Soluble Ash - the ratio of Soluble Ash to Brix is assumed to be constant between the feed bagasse and the product bagasse.
# Soluble Protein - the ratio of Soluble Protein to Brix is assumed to be constant between the feed bagasse and the product bagasse.
# Soluble Other - Soluble Other includes the other soluble species found in sugar cane and not specifically identified as a Reducing Sugar, Ash or Protein. The concentration of Soluble Other may be varied in the model in order to control the sugar purity in the product bagasse stream.

NB there may also be other soluble species in a sugar solution - for example salt, NaCl(aq). Individual species may be specified in the database rather than being lumped with ''Soluble Other''. All solutes are taken into account when calculating the properties of sugar solutions and in the calculation of purity and Brix. However, the split of the solutes for species other than the four listed above will be the same as that for sucrose (e.g. if 40% of the sucrose mass goes to juice, then 40% of the NaCl(aq) mass would go to juice). The Impurities Control option only manages the split of the species ''Soluble Other''.

'''Temperature''' - The temperatures of all product streams are assumed to be the same. The product temperature is calculated via energy balance and accounts for any environmental heat loss. Any enthalpy of dilution effects are implicitly included in the energy balance through the sugar properties model.

'''Solution''' - The model solves for the split of solids, water, sucrose and impurities between juice, bagasse and vent as well as for temperature. The various splits and temperature are all coupled and are solved iteratively within the model.

'''Filling Ratio and Filling RatioM''' - The ''FillingRatioM'' relates the volumetric flow of solids into a crusher to the ''escribed'' volumetric flow of the crusher. The ''FillingRatio'' relates the volumetric flow of solids in the product bagasse stream to the ''escribed'' volumetric flow of the crusher.

A single crusher generally has filling ratios defined in terms of the bagasse flows into or out of that particular crusher. For an ''isolated crusher'', the FillingRatioM is the volumetric flow of solids into the crusher divided by the escribed volumetric flow. The Filling Ratio is the volumetric flow of solids in the product bagasse stream (or feed flow in times separation efficiency) divided by the escribed volumetric flow of the crusher. The FillingRatio and FillingRatioM are related by the separation efficiency.

*<math> FillingRatioM = \left( \; \frac{\text{Volumetric Solids Flow to Crusher} \; }{\text{Escribed volumetric flow}} \; \right) </math>

*<math> FillingRatio = \left( \; \frac{\text{Volumetric Solids Flow to Product Bagasse} \quad}{\text{Escribed volumetric flow} \;} \right) </math>

*<math> FillingRatio = \left( \; FillingRatioM \times \text{Separation Efficiency} \; \right) </math>

For a crusher operating in a milling train with two or more crushers, the filling ratio may be defined ''relative'' to the flow of bagasse into the first crusher. Thus, for a crusher in a milling train that is ''referenced'' to a feed stream, the ''FillingRatioM'' is the reference volumetric flow of solids (usually the feed into the first crusher) divided by the escribed volumetric flow of the crusher.

*<math> FillingRatioM = \left( \frac{\text{Reference Volumetric Flow of Solids} \quad}{\text{Escribed Volumetric Flow of Crusher} \quad}\right) </math>

*<math> FillingRatio = \left(\frac{\text{Volumetric Solids Flow to Product Bagasse} \quad}{\text{Escribed volumetric flow} \quad}\right) </math>

And the ''FillingRatio'' and ''FillingRatioM'' are related by the reference and the product bagasse solids volumetric flows.

*<math> FillingRatio = \left(\frac{FillingRatioM \times \text{Volumetric Solids Flow to Product Bagasse} \quad} {\text{Reference Volumetric Flow of Solids} \quad}\right) </math>

=== Environmental Heat Exchange Options ===

The crusher unit may lose heat to the environment. All input streams are assumed to mix and come to thermal equilibrium. All of the output streams are assumed to be at the same temperature.

The heat loss options are set from a drop down list and include;

# None - No Heat Exchange occurs.
# FixedLoss - Heat Flow to the Environment is specified by the user.
# Ambient - A Heat Loss Constant is specified and heat loss is calculated as heat loss constant times the temperature difference between the product stream and ambient temperatures, Qloss = Constant * (Tprod - Tamb).
# Set_Tprod - The product stream is set to a User Specified Temperature

The Heat Flow is displayed for all options and heat flow ''from'' the crusher ''to'' the environment is ''positive'' in sign.

NB If a negative heat flow is reported, it indicates heat flow to the crusher from the environment for example if the product temperature is set higher than the input temperature.

=== Evaporation Loss Options ===

There may be significant evaporation from a sugar crusher when hot water is used for inhibition. The crusher unit operation has an option to allow water evaporation. The evaporation loss rate, ''EvapLossQm'', may be entered and this quantity of water will be split of from the mixed feed stream to the unit and turned to vapour. It will flow out through the vent (along with any other vapours that enter the unit). The temperature of the vapour stream will be the same as the product bagasse and juice streams. The latent heat of vaporisation is taken into account in the calculation of the product temperature. An estimate of this energy is displayed when there a non-zero evaporation loss is entered.

== Flow Chart ==

[[Image:Sugar Crusher Flow Diagram .jpg ]]

== Data Section ==

=== Sugar Crusher Access Page ===

'''Unit Type: SugarCrusher''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
==== Requirements ====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| ShowQFeed|| Tickbox || Optional display of all input material as one mixed stream (including all feed and imbibition streams).
|-
| TackStatus|| Tickbox || Optional display to display warnings.
|-
| font style="background: #ebebeb" colspan="3" | '''Environmental Heat Loss'''
|-
| valign="top" rowspan="4" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| SetTprod|| Product temperature is user input.
|-
| EnvLossRqd|| Input || The Required Environmental Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| EnvLossCoeff|| Input || The Environmental Heat Loss Rate Coefficient(kW/K) - This is only visible if the Ambient Method is selected.
|-
| FixedProductT || Input || The Required Product Temperature - This is only visible if the SetTprod Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' crusher ''to'' environment.).
|-
| font style="background: #ebebeb" colspan="3" | '''Evaporation Loss'''
|-
| EvapLossQm|| Input || User specified evaporation rate.
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporisation).
|-
| font style="background: #ebebeb" colspan="3" | '''Use Reference Stream'''
|-
| On || Tickbox || Tickbox to set the use reference stream option on or off.
|-
| StreamTag|| Input|| The name of the stream to use for reference calculations (this would typically be the feed bagasse stream into the first crusher in a milling train).
|-
| RefQv||font style="background: #ebebeb" | Display || Volumetric flow of the reference stream solids flow (for Filling Ratio Calculations).
|-
| RefPurity||font style="background: #ebebeb" | Display || Purity of the reference stream (for purity calculations).
|-
| RefBrix||font style="background: #ebebeb" | Display || Brix mass flow of the reference stream (for extraction calculations).
|-
| colspan="3" font style="background: #ebebeb" |

==== Imbibition Efficiency ====

|-
| ImbibitionCoeff|| Input || Imbibition Coefficient, Ic (%). Allowable Input Range is 1% to 200%.
|-
|FeedBrix ||font style="background: #ebebeb"| Display || Brix fraction of Cane/Bagasse Feed Stream (includes all feed streams summed into one stream).
|-
|ImbBrix||font style="background: #ebebeb"| Display || Brix fraction of Imbibition Stream (includes all imbibition streams summed into one stream).
|-
|TheoBrix||font style="background: #ebebeb"| Display || Theoretical Massecuite Brix fraction if all input streams are perfectly mixed.
|-
|JuiceBrix||font style="background: #ebebeb"| Display || Actual Juice Massecuite Brix fraction.
|-
|BagBrix||font style="background: #ebebeb"| Display || Actual Delivery Bagasse Massecuite Brix fraction.
|-
|TheoBagBrixQm||font style="background: #ebebeb"| Display || Theoretical Delivery Bagasse Brix Mass Flow.
|-
|TargetBagBrixQm||font style="background: #ebebeb"| Display || Target Delivery Bagasse Brix Mass Flow based on feed flows and input parameters.
|-
|BagasseBrixQm||font style="background: #ebebeb"| Display || Actual Delivery Bagasse Brix Mass Flow. This may be different than the target Brix flow if the model is unable to achieve the flow with the given feed and user inputs. A warning is displayed if any constraints are not met.
|-
| colspan="3" font style="background: #ebebeb" |

==== Mill Operation ====
Controls liquid flow to product Bagasse stream.
|-
|FillingRatioM|| Input || Filling RatioM, Filling Ratio is the total volumetric flow of solids divided by the escribed volume for a single mill referenced to itself. For a mill with another reference stream, the FillingRatioM is the is the reference stream solids volumetric flow divided by the escribed volume
|-
|FillingRatio||font style="background: #ebebeb"| Display || Filling Ratio - solids volumetric flow divided by the escribed volume. For a single mill (referenced to itself), FillingRatio = FillingRatioM
|-
|ReAbsorptionFac|| Input || Re-absorption Factor, K. Allowable Input Range is (FillingRatio + 0.01) to 10.0 (NB re-absorption factor must be larger than the filling ratio).
|-
|RatioVjVb||font style="background: #ebebeb"| Display || Required Volumetric Flow Ratio of Juice to Solids.
|-
|Escribedvolume||font style="background: #ebebeb"| Display || Volumetric Flow - width of rolls times work opening times surface speed of rolls.
|-
|TotalSolidsQv||font style="background: #ebebeb"| Display || Total Volumetric Flow of Solids to the Crusher.
|-
|BagasseSolQv||font style="background: #ebebeb"| Display || Volumetric Flow of Solids to Delivery Bagasse Stream.
|-
|TheoBagLiqQv ||font style="background: #ebebeb"| Display || Theoretical Liquid Volume Flow Required.
|-
|BagasseLiqQv ||font style="background: #ebebeb"| Display || Actual Liquid Volume Flow to Delivery Bagasse Stream. A warning will be displayed if the model is unable to achieve the required volumetric flow rate.
|-
| colspan="3" font style="background: #ebebeb" |

==== Solids ====
Display Solids Concentrations and Mass Flows.
|-
| SepEfficiency|| Input || The Required Solids Separation Efficiency. This specifies the mass fraction of total solids input reporting to the delivery bagasse stream. Allowable Input Range is 10% to 100%.
|-
|JuiceSolids||font style="background: #ebebeb"| Display || Mass Percentage Solids Concentration (wt/wt) in product Juice stream.
|-
|BagasseSolids||font style="background: #ebebeb"| Display || Mass Percentage Solids Concentration (wt/wt) in product Bagasse stream.
|-
|JuiceSolConc25||font style="background: #ebebeb"| Display || Solids Concentration (wt/vol) in product Juice stream.
|-
|BagasseSolConc25||font style="background: #ebebeb"| Display || Solids Concentration (wt/vol) in product Bagasse stream.
|-
|SolidsJuiceQm||font style="background: #ebebeb"| Display || Solids Mass Flow in product Juice stream.
|-
|SolidsBagasseQm||font style="background: #ebebeb"| Display || Solids Mass Flow in product Bagasse stream.
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Crusher | Group=Sugar }}

Sugar Crusher

2025-08-08T15:40:55Z

John.McFeaters: /* General Description */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=3}}
----
{{TOC}}
== General Description ==

The sugar crusher unit operation is available with the Sugar add-on.

The sugar crusher receives shredded cane (or bagasse from an upstream mill) and passes it through rolls to squeeze juice out of it. There may be an optional imbibition streams added to help wash out sucrose rich juice. There is a product juice stream, a delivery (or product) bagasse stream and a vent stream exiting the crusher.

All streams entering the crusher are assumed to mix perfectly and then the flow of solids, sucrose and impurities are split between juice, bagasse and vent to meet the specified operating parameters.

Solids are split between the juice and delivery bagasse streams according to the user specified separation efficiency.

Water and various solutes may be split in different relative proportions to the juice and bagasse streams to allow the product streams to have different Brix, overall purity and specific impurities ratios. The splits are calculated to satisfy the user specified ''Imbibition Coefficient, Ic'' and when the optional ''Purity Control'' is selected a user specified purity ratio. The feed and product streams in sugar crusher would typically use the [[Sugar Species Model]].

The volumetric flow of liquid going to the delivery bagasse stream is determined by the volumetric flow of solids to the bagasse stream and the user specified ''Filling Ratio, C'' and ''Re-absorption Factor, K''.

The crusher model includes optional heat loss to the environment and there are several different heat loss models available. The crusher also includes the option to specify evaporation rate from it
and this is included in the energy balance.

Any vapours in the input streams or from evaporation are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams and there is no vent connected.

The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant Model - Environment]]).

The crusher has the option to use a ''user specified reference stream''. Data from this stream may then be used for doing purity, extraction and volumetric flow calculations relative to the reference stream. Typically the reference stream would be the shredded cane going into the first crusher in a milling train.

== Inputs and Outputs ==

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max''' ||  
|-
| FeedBag || Required || In || 1 || 1 || Feed Bagasse to the Crusher - shredded cane or bagasse from a previous mill stage.
|-
| Imbibition || Optional || In || 0 || 5 || Optional Imbibition Streams.
|-
| Juice || Required || Out || 1 || 1 || Primarily liquid squeezed from the bagasse - may have some solids content.
|-
| Bagasse|| Required || Out || 1 || 1 || Delivery (or Product) Bagasse - most of the input solids, with some liquid.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapours - not required if there are no vapours present.
|-
|}

NB Aqueous Sucrose must be present in the Feed Bagasse stream or an error will be reported.

== Behavior when Model is OFF ==

The sugar crusher unit may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off it is basically bypassed and the following behavior occurs:
* All material in streams connected to ''Feed'' will flow straight through to the product Bagasse stream with no changes or heat exchange.
* All material in streams connected to ''Imbibition'' will flow through to the product Juice stream with no changes or heat exchange.
* There will be no heat transfer to the environment.

NB any gases in either feed or imbibition streams will remain with those streams when the unit is off.

== Model Theory ==

The input streams to the crusher are the ''Feed Bagasse'' stream which is the shredded sugar cane or bagasse from a previous mill stage and the ''Imbibition'' stream which is usually lower Brix juice from a downstream mill stage or water. All of the input and output streams are a mixture of solids and liquids. The solids are primarily plant fiber but may contain mud and other material. The liquids are primarily sucrose-water solutions with some aqueous impurities. NB Brix refers to ''all'' solutes in the liquid phase - or basically everything except water.

The model allows for multiple imbibition streams. All the feed and imbibition streams are assumed to mix perfectly in the crusher. The flows of solids, Brix and water must then be split to satisfy the user specified operating parameters.

The output streams are ''Juice'' which is primarily liquid although may have some solids, ''Bagasse'' which is most of the fiber and some liquid and a ''Vent'' for gases. These are shown in the flow chart below.

'''Gases''' - Any gases present in any of the input streams are split off and go to the vent stream. If there is no vent attached, the gases are sent out with the juice stream and a warning is displayed that there are gases present, but no vent.

'''Solids''' - Solids from mixed input stream split according to the user specified ''Separation Coefficient'' (which is the mass fraction of solids reporting to bagasse). Generally, most of the solids report to the bagasse stream and any remaining solids report to the juice stream.

'''Liquids''' - The overall split of liquid between juice and bagasse streams is calculated to give the required volumetric flow of juice going to the product bagasse stream. This flow is determined by the volumetric flow of solids, the ''Filling Ratio'' and the ''Re-absorption Factor''. The required volumetric flow ratio of juice to solids is given by; Vj/Vs = (Re-absorption Factor - Filling Ratio) / Filling Ratio. (NB the mass of liquid going to bagasse depends on the liquid density).

The individual split of water and Brix is based on the ''Imbibition Coefficient, Ic'' which is a measure of actual Brix extraction to theoretical Brix extraction. It is possible to have an imbibition coefficient that is greater or less than than one and the Brix of the juice and bagasse streams may be different. When the imbibition coefficient is one the Brix of the juice and bagasse streams are equal, when it is less than one, the bagasse Brix is higher than the juice Brix and when it is greater than one the juice Brix is higher then the bagasse Brix. The SysCAD sugar crusher model splits water and Brix to match the imbibition coefficient with the constraint that the required volume flow to delivery bagasse must be met (and also that various constraints on impurities are met so that the ratio of sucrose to impurities is may also be adjusted between the bagasse and juice streams - see below).

A theoretical Brix is calculated assuming a perfect mixture of all the streams coming in and the imbibition coefficient is the actual Brix mass flow to juice divided by the theoretical Brix mass flow to juice.

*<math> \text{Imbibition Coefficient, Ic} = \frac {(\text{Brix into Crusher} \quad - \quad \text{Brix in Delivery Bagasse} \;)}{(\text{Brix into Crusher} \quad- \quad \text{Theoretical Brix in Delivery Bagasse} \;)}</math>

'''Impurities''' - The impurities include ''all'' solutes other than sucrose. The sugar crusher model identifies four specific impurities that normally derived from the analysis of bagasse. These species are managed individually in the crusher model and must be present in the species data base (although their mass flows may be set to zero). The species and the control of them is as follows;

# Reducing Sugars - the ratio of reducing sugars to Pol is assumed to be constant between the feed bagasse and product bagasse.
# Soluble Ash - the ratio of Soluble Ash to Brix is assumed to be constant between the feed bagasse and the product bagasse.
# Soluble Protein - the ratio of Soluble Protein to Brix is assumed to be constant between the feed bagasse and the product bagasse.
# Soluble Other - Soluble Other includes the other soluble species found in sugar cane and not specifically identified as a Reducing Sugar, Ash or Protein. The concentration of Soluble Other may be varied in the model in order to control the sugar purity in the product bagasse stream.

NB there may also be other soluble species in a sugar solution - for example salt, NaCl(aq). Individual species may be specified in the database rather than being lumped with ''Soluble Other''. All solutes are taken into account when calculating the properties of sugar solutions and in the calculation of purity and Brix. However, the split of the solutes for species other than the four listed above will be the same as that for sucrose (e.g. if 40% of the sucrose mass goes to juice, then 40% of the NaCl(aq) mass would go to juice). The Impurities Control option only manages the split of the species ''Soluble Other''.

'''Temperature''' - The temperatures of all product streams are assumed to be the same. The product temperature is calculated via energy balance and accounts for any environmental heat loss. Any enthalpy of dilution effects are implicitly included in the energy balance through the sugar properties model.

'''Solution''' - The model solves for the split of solids, water, sucrose and impurities between juice, bagasse and vent as well as for temperature. The various splits and temperature are all coupled and are solved iteratively within the model.

'''Filling Ratio and Filling RatioM''' - The ''FillingRatioM'' relates the volumetric flow of solids into a crusher to the ''escribed'' volumetric flow of the crusher. The ''FillingRatio'' relates the volumetric flow of solids in the product bagasse stream to the ''escribed'' volumetric flow of the crusher.

A single crusher generally has filling ratios defined in terms of the bagasse flows into or out of that particular crusher. For an ''isolated crusher'', the FillingRatioM is the volumetric flow of solids into the crusher divided by the escribed volumetric flow. The Filling Ratio is the volumetric flow of solids in the product bagasse stream (or feed flow in times separation efficiency) divided by the escribed volumetric flow of the crusher. The FillingRatio and FillingRatioM are related by the separation efficiency.

*<math> FillingRatioM = \left( \; \frac{\text{Volumetric Solids Flow to Crusher} \; }{\text{Escribed volumetric flow}} \; \right) </math>

*<math> FillingRatio = \left( \; \frac{\text{Volumetric Solids Flow to Product Bagasse} \quad}{\text{Escribed volumetric flow} \;} \right) </math>

*<math> FillingRatio = \left( \; FillingRatioM \times \text{Separation Efficiency} \; \right) </math>

For a crusher operating in a milling train with two or more crushers, the filling ratio may be defined ''relative'' to the flow of bagasse into the first crusher. Thus, for a crusher in a milling train that is ''referenced'' to a feed stream, the ''FillingRatioM'' is the reference volumetric flow of solids (usually the feed into the first crusher) divided by the escribed volumetric flow of the crusher.

*<math> FillingRatioM = \left( \frac{\text{Reference Volumetric Flow of Solids} \quad}{\text{Escribed Volumetric Flow of Crusher} \quad}\right) </math>

*<math> FillingRatio = \left(\frac{\text{Volumetric Solids Flow to Product Bagasse} \quad}{\text{Escribed volumetric flow} \quad}\right) </math>

And the ''FillingRatio'' and ''FillingRatioM'' are related by the reference and the product bagasse solids volumetric flows.

*<math> FillingRatio = \left(\frac{FillingRatioM \times \text{Volumetric Solids Flow to Product Bagasse} \quad} {\text{Reference Volumetric Flow of Solids} \quad}\right) </math>

=== Environmental Heat Exchange Options ===

The crusher unit may lose heat to the environment. All input streams are assumed to mix and come to thermal equilibrium. All of the output streams are assumed to be at the same temperature.

The heat loss options are set from a drop down list and include;

# None - No Heat Exchange occurs.
# FixedLoss - Heat Flow to the Environment is specified by the user.
# Ambient - A Heat Loss Constant is specified and heat loss is calculated as heat loss constant times the temperature difference between the product stream and ambient temperatures, Qloss = Constant * (Tprod - Tamb).
# Set_Tprod - The product stream is set to a User Specified Temperature

The Heat Flow is displayed for all options and heat flow ''from'' the crusher ''to'' the environment is ''positive'' in sign.

NB If a negative heat flow is reported, it indicates heat flow to the crusher from the environment for example if the product temperature is set higher than the input temperature.

=== Evaporation Loss Options ===

There may be significant evaporation from a sugar crusher when hot water is used for inhibition. The crusher unit operation has an option to allow water evaporation. The evaporation loss rate, ''EvapLossQm'', may be entered and this quantity of water will be split of from the mixed feed stream to the unit and turned to vapour. It will flow out through the vent (along with any other vapours that enter the unit). The temperature of the vapour stream will be the same as the product bagasse and juice streams. The latent heat of vaporisation is taken into account in the calculation of the product temperature. An estimate of this energy is displayed when there a non-zero evaporation loss is entered.

== Flow Chart ==

[[Image:Sugar Crusher Flow Diagram .jpg ]]

== Data Section ==

=== Sugar Crusher Access Page ===

'''Unit Type: SugarCrusher''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
==== Requirements ====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| ShowQFeed|| Tickbox || Optional display of all input material as one mixed stream (including all feed and imbibition streams).
|-
| TackStatus|| Tickbox || Optional display to display warnings.
|-
| font style="background: #ebebeb" colspan="3" | '''Environmental Heat Loss'''
|-
| valign="top" rowspan="4" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| SetTprod|| Product temperature is user input.
|-
| EnvLossRqd|| Input || The Required Environmental Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| EnvLossCoeff|| Input || The Environmental Heat Loss Rate Coefficient(kW/K) - This is only visible if the Ambient Method is selected.
|-
| FixedProductT || Input || The Required Product Temperature - This is only visible if the SetTprod Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' crusher ''to'' environment.).
|-
| font style="background: #ebebeb" colspan="3" | '''Evaporation Loss'''
|-
| EvapLossQm|| Input || User specified evaporation rate.
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporisation).
|-
| font style="background: #ebebeb" colspan="3" | '''Use Reference Stream'''
|-
| On || Tickbox || Tickbox to set the use reference stream option on or off.
|-
| StreamTag|| Input|| The name of the stream to use for reference calculations (this would typically be the feed bagasse stream into the first crusher in a milling train).
|-
| RefQv||font style="background: #ebebeb" | Display || Volumetric flow of the reference stream solids flow (for Filling Ratio Calculations).
|-
| RefPurity||font style="background: #ebebeb" | Display || Purity of the reference stream (for purity calculations).
|-
| RefBrix||font style="background: #ebebeb" | Display || Brix mass flow of the reference stream (for extraction calculations).
|-
| colspan="3" font style="background: #ebebeb" |

==== Imbibition Efficiency ====

|-
| ImbibitionCoeff|| Input || Imbibition Coefficient, Ic (%). Allowable Input Range is 1% to 200%.
|-
|FeedBrix ||font style="background: #ebebeb"| Display || Brix fraction of Cane/Bagasse Feed Stream (includes all feed streams summed into one stream).
|-
|ImbBrix||font style="background: #ebebeb"| Display || Brix fraction of Imbibition Stream (includes all imbibition streams summed into one stream).
|-
|TheoBrix||font style="background: #ebebeb"| Display || Theoretical Massecuite Brix fraction if all input streams are perfectly mixed.
|-
|JuiceBrix||font style="background: #ebebeb"| Display || Actual Juice Massecuite Brix fraction.
|-
|BagBrix||font style="background: #ebebeb"| Display || Actual Delivery Bagasse Massecuite Brix fraction.
|-
|TheoBagBrixQm||font style="background: #ebebeb"| Display || Theoretical Delivery Bagasse Brix Mass Flow.
|-
|TargetBagBrixQm||font style="background: #ebebeb"| Display || Target Delivery Bagasse Brix Mass Flow based on feed flows and input parameters.
|-
|BagasseBrixQm||font style="background: #ebebeb"| Display || Actual Delivery Bagasse Brix Mass Flow. This may be different than the target Brix flow if the model is unable to achieve the flow with the given feed and user inputs. A warning is displayed if any constraints are not met.
|-
| colspan="3" font style="background: #ebebeb" |

==== Mill Operation ====
Controls liquid flow to product Bagasse stream.
|-
|FillingRatioM|| Input || Filling RatioM, Filling Ratio is the total volumetric flow of solids divided by the escribed volume for a single mill referenced to itself. For a mill with another reference stream the FillingRatioM is the
|-
|FillingRatio||font style="background: #ebebeb"| Display || Filling Ratio - solids volumetric flow divided by the escribed volume. For a single mill (referenced to itself), FillingRatio = FillingRatioM
|-
|ReAbsorptionFac|| Input || Re-absorption Factor, K. Allowable Input Range is (FillingRatio + 0.01) to 10.0 (NB re-absorption factor must be larger than the filling ratio).
|-
|RatioVjVb||font style="background: #ebebeb"| Display || Required Volumetric Flow Ratio of Juice to Solids.
|-
|Escribedvolume||font style="background: #ebebeb"| Display || Volumetric Flow - width of rolls times work opening times surface speed of rolls.
|-
|TotalSolidsQv||font style="background: #ebebeb"| Display || Total Volumetric Flow of Solids to the Crusher.
|-
|BagasseSolQv||font style="background: #ebebeb"| Display || Volumetric Flow of Solids to Delivery Bagasse Stream.
|-
|TheoBagLiqQv ||font style="background: #ebebeb"| Display || Theoretical Liquid Volume Flow Required.
|-
|BagasseLiqQv ||font style="background: #ebebeb"| Display || Actual Liquid Volume Flow to Delivery Bagasse Stream. A warning will be displayed if the model is unable to achieve the required volumetric flow rate.
|-
| colspan="3" font style="background: #ebebeb" |

==== Solids ====
Display Solids Concentrations and Mass Flows.
|-
| SepEfficiency|| Input || The Required Solids Separation Efficiency. This specifies the mass fraction of total solids input reporting to the delivery bagasse stream. Allowable Input Range is 10% to 100%.
|-
|JuiceSolids||font style="background: #ebebeb"| Display || Mass Percentage Solids Concentration (wt/wt) in product Juice stream.
|-
|BagasseSolids||font style="background: #ebebeb"| Display || Mass Percentage Solids Concentration (wt/wt) in product Bagasse stream.
|-
|JuiceSolConc25||font style="background: #ebebeb"| Display || Solids Concentration (wt/vol) in product Juice stream.
|-
|BagasseSolConc25||font style="background: #ebebeb"| Display || Solids Concentration (wt/vol) in product Bagasse stream.
|-
|SolidsJuiceQm||font style="background: #ebebeb"| Display || Solids Mass Flow in product Juice stream.
|-
|SolidsBagasseQm||font style="background: #ebebeb"| Display || Solids Mass Flow in product Bagasse stream.
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Crusher | Group=Sugar }}

Species Table - Thermodynamic Data

2025-08-07T22:45:06Z

John.McFeaters: /* Heat of Formation (H25) with Heat of Dilution Correction */

[[Category:Species]] [[Category:Properties]] [[Category:Energy]]
{{Navigation|[[User Guide]]|[[Species Table]]|altname=Thermodynamic Data}}
{{Species Database Header tabs | currentpage=5}}
----
{{TOC}}
== Introduction ==

This is information is generally required for all species, unless the project is not using the Energy Balance Add-On and/or with Heat Calculations switched off.

'''Notes:'''
# Species that have been added to represent gangue material, such as Inerts, Ore, etc. will generally not have any thermodynamic data.
# When importing Species from the HSC database that have a structural change at temperature, for example solids in smelters or furnaces where they change between alpha and beta states, SysCAD manipulates the Heat of Formation to take the enthalpy of phase change into account. Please see '''[[Importing Species into User Species Database#Importing_Species_from_HSC_Database|Importing Species from HSC Database]]'''.

== Heat of Formation (H25) ==

This field is '''optional''' (but is usually defined).

This is the Heat of Formation at 25 °C. The unit is expressed in J/mol.

If this field is left blank, SysCAD will assume a value of 0 J/mol at 0°C.

For some Cp correlations, for example NASAGlenn_Cp and Gibbs_Cp, the value for H25 can be calculated directly from the Cp equation parameters. The user can then enter "FromCp()" which tells SysCAD to calculate the value for H25 for the enthalpy equation from the selected Cp equation. When selecting these types of Cp correlations and there are inconsistencies between the entered H25 and calculated H25 an error is given.

This value is used to calculate heats of reaction for chemical reactions specified in SysCAD. If the compound is used in chemical reactions, this number will determine the accuracy of the energy balance. If this field is left blank due to lack of data, then the user should define the Heat of Reaction (HOR) manually in the reaction file. See '''[[Reaction Block (RB)]]''' for further information on reactions.

Refer to [[Stream Properties using Standard Method#Stream Heat of Formation values (Hf)|Stream Heat of Formation values (Hf)]] for an example of how these individual heats of formation are used to determine the heat of formation of a stream.

'''Notes:'''
# All elements in their Standard State should have zero heat of formation at 25 °C.
#* Examples of elements in their standard state: O2(g), N2(g), C(s) - where C is graphite.
# H+(aq) should have zero heat of formation at 25 °C. Projects with H+(aq) which use a non-zero value will not load.

The image below shows the dialog box for the User values of H25:

[[Image:Species Editing H25 1.png]]

* For most species, the user will enter a single Constant Value.
* However, in some cases, especially for acids or bases, the user may prefer to enter a range of H25 values for different mass fractions in solution. This allows SysCAD to then calculate the energy released or absorbed when solutions of different mass concentrations are mixed. This is discussed in the section below:

=== Heat of Formation (H25) with Heat of Dilution Correction ===

When the concentration of some aqueous solute species in a solution are changed there can be a significant change in the enthalpy of those species. While this effect is usually negligible for most solutes, it is important for strong acids or bases. The most well known example of this effect is diluting concentrated sulfuric acid with water - this is highly exothermic and can result in a large temperature increase of the resulting solution.

The Heat of Formation data entered with the Heat of Dilution correction will enable SysCAD to calculate the heat of formation of a species in solution taking into account the effect of heat of dilution (the energy released or absorbed when the concentration of that species is changed). This is important for calculating the change in temperature associated with dilution or concentration of that species and also for calculating the heat of reaction if that species is formed or consumed by chemical reactions or phase change.

NB it is important to note that the enthalpy data entered into SysCAD for that species ''must'' include the heat of formation of the aqueous species at infinite dilution - this term is typically much larger than the effect of changing concentration. If this term is left out, calculation of the heat of reaction for any reaction involving this species will be grossly in error (including simple phase change without chemical reaction).

Heat of dilution data is often presented in different formats and is frequently given in a table as the difference in enthalpy between the species at some concentration and at infinite dilution. In this format, it does not include the heat of formation at infinite dilution and that must then be added into the data before entry into SysCAD.

An example is given here for hydrochloric acid, HCl(aq). If the concentration of the HCl(aq) in the solution is changed, the heat of formation will change. Data for the ''heat of dilution'' is in the table below <ref> Parker, V. B., Thermal Properties of Aqueous Uni-Univalent Electrolytes, Natl. Stand. Ref. Data Ser. - Natl. Bur. Stand. (U.S.) 2, U.S. Government Printing Office, 1965. </ref>. The heat of dilution data, the -dHdil column, is given as the negative of the amount of heat released when a solution at the given concentration is diluted to infinite dilution so that value should be added to the heat of formation at infinite dilution to get the heat of formation at the given concentration. The heat of formation of HCl(aq) at infinite dilution is -166.99 kJ/mol and the data in the right most column are the heats of formation at the given concentrations that calculated by adding the heat of dilution to the heat of formation.

[[File:HCl dat3.jpg]]

The ''heat of formation data'' in the right most column can be curve fit as a function of mass fraction or the entered as a table and have SysCAD fit a cubic spline to the data. It is important that when doing the curve fit that the entire range of possible concentrations is covered - i.e. from 0% to 100% solute. Even though the solution may never reach that concentration, it is important to cover the full range for numerical stability. Higher order curves fits are often required to match the data and stepping even slightly outside of the data range can result in unpredictable results. In the example here, the original data only go to 66.9% mass fraction HCl so we extrapolated to 100% using the last two data points. The plot below shows the logarithm of the heat of dilution versus HCl mass fraction. The right most two columns woudl be entered into the spline fit entry as per the notes below.

[[File:HCl_Plot.jpg]]

'''Notes:'''
# A polynomial will be processed more quickly within SysCAD and hence is preferred to a table of data.
# If you use a table of data (Spline under Tension), you must have data points for the mass fraction of the species at 0 and 100%.
# The best way to enter the table of values, is to have the data in an Excel spreadsheet in 2 adjacent columns - the first containing the Mass Fraction, and the second with the H25. Copy the 2 columns of data and paste them into the table in SysCAD. See the image below:
#:[[Image:Species Editing Heat of Dilution.png]]

=== Heat of Transition ===

If the heat capacity range for a species does not include 25 °C (298.15K), then the enthalpy at the starting temperature of the heat capacity range (Ts) will be calculated as follows:

<math> H (Ts) = H_f (298.15K) + C_p \times (Ts - 298.15) </math>

where Cp is the heat capacity at Ts.

Thus if the enthalpy at Ts is known, the user can calculate what Hf should be entered in order to achieve this enthalpy in SysCAD.

This is similar to what SysCAD does automatically when importing species data from the HSC Database (refer to [[Importing_Species_into_User_Species_Database#Importing_Species_with_Phase_Change_From_HSC|Importing Species from HSC Database]]).

== Entropy (S25) ==

This field is '''optional'''.

This is the ''absolute'' entropy value for the species at reference temperature. The unit for Entropy is J/mol.K.

For some Cp correlations, for example NASAGlenn_Cp and Gibbs_Cp, the value for S25 can be calculated directly from the Cp equation parameters. The user can then enter "FromCp()" which tells SysCAD to calculate the value for S25 for the entropy equation from the selected Cp equation. When selecting these types of Cp correlations and there are inconsistencies between the entered S25 and calculated S25 an error is given. This is new to Build 138.

Entropy values are normally only used in Free Energy Minimisation (FEM) or adiabatic (isentropic) calculations. For isentropic calculation (e.g. compressor or turbine models), only ''differences'' in entropy are used, so this value need not be specified. However for FEM calculations, the absolute entropy is required and this value must be provided.

For gases (except steam), as well as integrating Cp/T with respect to temperature, a pressure term is included:
:-R * ln(P/Po)
:where R = gas constant
:::P = partial pressure
:::Po = reference pressure (1 atm)

Steam entropy is also a function of both temperature and pressure.

Refer to [[Stream Properties using Standard Method#Stream Entropy values (S)|Stream Entropy (S)]] for an example of how these individual entropies are used to determine the entropy of a stream.

'''Note:''' H+(aq) should have zero entropy at 25 °C. Projects with H+(aq) which use a non-zero value will not load.

Species Table - Thermodynamic Data

2025-08-07T22:43:11Z

John.McFeaters: /* Heat of Formation (H25) with Heat of Dilution Correction */

[[Category:Species]] [[Category:Properties]] [[Category:Energy]]
{{Navigation|[[User Guide]]|[[Species Table]]|altname=Thermodynamic Data}}
{{Species Database Header tabs | currentpage=5}}
----
{{TOC}}
== Introduction ==

This is information is generally required for all species, unless the project is not using the Energy Balance Add-On and/or with Heat Calculations switched off.

'''Notes:'''
# Species that have been added to represent gangue material, such as Inerts, Ore, etc. will generally not have any thermodynamic data.
# When importing Species from the HSC database that have a structural change at temperature, for example solids in smelters or furnaces where they change between alpha and beta states, SysCAD manipulates the Heat of Formation to take the enthalpy of phase change into account. Please see '''[[Importing Species into User Species Database#Importing_Species_from_HSC_Database|Importing Species from HSC Database]]'''.

== Heat of Formation (H25) ==

This field is '''optional''' (but is usually defined).

This is the Heat of Formation at 25 °C. The unit is expressed in J/mol.

If this field is left blank, SysCAD will assume a value of 0 J/mol at 0°C.

For some Cp correlations, for example NASAGlenn_Cp and Gibbs_Cp, the value for H25 can be calculated directly from the Cp equation parameters. The user can then enter "FromCp()" which tells SysCAD to calculate the value for H25 for the enthalpy equation from the selected Cp equation. When selecting these types of Cp correlations and there are inconsistencies between the entered H25 and calculated H25 an error is given.

This value is used to calculate heats of reaction for chemical reactions specified in SysCAD. If the compound is used in chemical reactions, this number will determine the accuracy of the energy balance. If this field is left blank due to lack of data, then the user should define the Heat of Reaction (HOR) manually in the reaction file. See '''[[Reaction Block (RB)]]''' for further information on reactions.

Refer to [[Stream Properties using Standard Method#Stream Heat of Formation values (Hf)|Stream Heat of Formation values (Hf)]] for an example of how these individual heats of formation are used to determine the heat of formation of a stream.

'''Notes:'''
# All elements in their Standard State should have zero heat of formation at 25 °C.
#* Examples of elements in their standard state: O2(g), N2(g), C(s) - where C is graphite.
# H+(aq) should have zero heat of formation at 25 °C. Projects with H+(aq) which use a non-zero value will not load.

The image below shows the dialog box for the User values of H25:

[[Image:Species Editing H25 1.png]]

* For most species, the user will enter a single Constant Value.
* However, in some cases, especially for acids or bases, the user may prefer to enter a range of H25 values for different mass fractions in solution. This allows SysCAD to then calculate the energy released or absorbed when solutions of different mass concentrations are mixed. This is discussed in the section below:

=== Heat of Formation (H25) with Heat of Dilution Correction ===

When the concentration of some aqueous solute species in a solution are changed there can be a significant change in the enthalpy of those species. While this effect is usually negligible for most solutes, it is important for strong acids or bases. The most well known example of this effect is diluting concentrated sulfuric acid with water - this is highly exothermic and can result in a large temperature increase of the resulting solution.

The Heat of Formation data entered with the Heat of Dilution correction will enable SysCAD to calculate the heat of formation of a species in solution taking into account the effect of heat of dilution (the energy released or absorbed when the concentration of that species is changed). This is important for calculating the change in temperature associated with dilution or concentration of that species and also for calculating the heat of reaction if that species is formed or consumed by chemical reactions or phase change.

NB it is important to note that the enthalpy data entered into SysCAD for that species ''must'' include the heat of formation of the aqueous species at infinite dilution - this term is typically much larger than the effect of changing concentration. If this term is left out, calculation of the heat of reaction for any reaction involving this species will be grossly in error (including simple phase change without chemical reaction).

Heat of dilution data is often presented in different formats and is frequently given in a table as the difference in enthalpy between the species at some concentration and at infinite dilution. In this format, it does not include the heat of formation at infinite dilution and that must then be added into the data before entry into SysCAD.

An example is given here for hydrochloric acid, HCl(aq). If the concentration of the HCl(aq) in the solution is changed, the heat of formation will change. Data for the ''heat of dilution'' is in the table below<ref> Parker, V. B., Thermal Properties of Aqueous Uni-Univalent Electrolytes, Natl. Stand. Ref. Data Ser. - Natl. Bur. Stand. (U.S.) 2, U.S. Government Printing Office, 1965. </ref>. The data, -dHdil column, is given as the negative of the amount of heat released when a solution at the given concentration is diluted to infinite dilution so that value should be added to the heat of formation at infinite dilution to get the heat of formation at the given concentration. The heat of formation of HCl(aq) at infinite dilution is -166.99 kJ/mol and the data in the right most column are the heats of formation at the given concentrations that calculated by adding the heat of dilution to the heat of formation.

[[File:HCl dat3.jpg]]

The ''heat of formation data'' in the right most column can be curve fit as a function of mass fraction or the entered as a table and have SysCAD fit a cubic spline to the data. It is important that when doing the curve fit that the entire range of possible concentrations is covered - i.e. from 0% to 100% solute. Even though the solution may never reach that concentration, it is important to cover the full range for numerical stability. Higher order curves fits are often required to match the data and stepping even slightly outside of the data range can result in unpredictable results. In the example here, the original data only go to 66.9% mass fraction HCl so we extrapolated to 100% using the last two data points. The plot below shows the logarithm of the heat of dilution versus HCl mass fraction. The right most two columns woudl be entered into the spline fit entry as per the notes below.

[[File:HCl_Plot.jpg]]

'''Notes:'''
# A polynomial will be processed more quickly within SysCAD and hence is preferred to a table of data.
# If you use a table of data (Spline under Tension), you must have data points for the mass fraction of the species at 0 and 100%.
# The best way to enter the table of values, is to have the data in an Excel spreadsheet in 2 adjacent columns - the first containing the Mass Fraction, and the second with the H25. Copy the 2 columns of data and paste them into the table in SysCAD. See the image below:
#:[[Image:Species Editing Heat of Dilution.png]]

=== Heat of Transition ===

If the heat capacity range for a species does not include 25 °C (298.15K), then the enthalpy at the starting temperature of the heat capacity range (Ts) will be calculated as follows:

<math> H (Ts) = H_f (298.15K) + C_p \times (Ts - 298.15) </math>

where Cp is the heat capacity at Ts.

Thus if the enthalpy at Ts is known, the user can calculate what Hf should be entered in order to achieve this enthalpy in SysCAD.

This is similar to what SysCAD does automatically when importing species data from the HSC Database (refer to [[Importing_Species_into_User_Species_Database#Importing_Species_with_Phase_Change_From_HSC|Importing Species from HSC Database]]).

== Entropy (S25) ==

This field is '''optional'''.

This is the ''absolute'' entropy value for the species at reference temperature. The unit for Entropy is J/mol.K.

For some Cp correlations, for example NASAGlenn_Cp and Gibbs_Cp, the value for S25 can be calculated directly from the Cp equation parameters. The user can then enter "FromCp()" which tells SysCAD to calculate the value for S25 for the entropy equation from the selected Cp equation. When selecting these types of Cp correlations and there are inconsistencies between the entered S25 and calculated S25 an error is given. This is new to Build 138.

Entropy values are normally only used in Free Energy Minimisation (FEM) or adiabatic (isentropic) calculations. For isentropic calculation (e.g. compressor or turbine models), only ''differences'' in entropy are used, so this value need not be specified. However for FEM calculations, the absolute entropy is required and this value must be provided.

For gases (except steam), as well as integrating Cp/T with respect to temperature, a pressure term is included:
:-R * ln(P/Po)
:where R = gas constant
:::P = partial pressure
:::Po = reference pressure (1 atm)

Steam entropy is also a function of both temperature and pressure.

Refer to [[Stream Properties using Standard Method#Stream Entropy values (S)|Stream Entropy (S)]] for an example of how these individual entropies are used to determine the entropy of a stream.

'''Note:''' H+(aq) should have zero entropy at 25 °C. Projects with H+(aq) which use a non-zero value will not load.

File:HCl dat3.jpg

2025-08-07T22:36:36Z

John.McFeaters:

File:HCl dat2.jpg

2025-08-07T22:28:05Z

John.McFeaters: John.McFeaters uploaded a new version of File:HCl dat2.jpg

== Summary ==
HCl heat of dilution

File:HCl Plot.jpg

2025-08-07T22:02:16Z

John.McFeaters:

Species Table - Thermodynamic Data

2025-08-07T21:58:28Z

John.McFeaters: /* Hf(25) with Heat of Dilution Correction */

[[Category:Species]] [[Category:Properties]] [[Category:Energy]]
{{Navigation|[[User Guide]]|[[Species Table]]|altname=Thermodynamic Data}}
{{Species Database Header tabs | currentpage=5}}
----
{{TOC}}
== Introduction ==

This is information is generally required for all species, unless the project is not using the Energy Balance Add-On and/or with Heat Calculations switched off.

'''Notes:'''
# Species that have been added to represent gangue material, such as Inerts, Ore, etc. will generally not have any thermodynamic data.
# When importing Species from the HSC database that have a structural change at temperature, for example solids in smelters or furnaces where they change between alpha and beta states, SysCAD manipulates the Heat of Formation to take the enthalpy of phase change into account. Please see '''[[Importing Species into User Species Database#Importing_Species_from_HSC_Database|Importing Species from HSC Database]]'''.

== Heat of Formation (H25) ==

This field is '''optional''' (but is usually defined).

This is the Heat of Formation at 25 °C. The unit is expressed in J/mol.

If this field is left blank, SysCAD will assume a value of 0 J/mol at 0°C.

For some Cp correlations, for example NASAGlenn_Cp and Gibbs_Cp, the value for H25 can be calculated directly from the Cp equation parameters. The user can then enter "FromCp()" which tells SysCAD to calculate the value for H25 for the enthalpy equation from the selected Cp equation. When selecting these types of Cp correlations and there are inconsistencies between the entered H25 and calculated H25 an error is given.

This value is used to calculate heats of reaction for chemical reactions specified in SysCAD. If the compound is used in chemical reactions, this number will determine the accuracy of the energy balance. If this field is left blank due to lack of data, then the user should define the Heat of Reaction (HOR) manually in the reaction file. See '''[[Reaction Block (RB)]]''' for further information on reactions.

Refer to [[Stream Properties using Standard Method#Stream Heat of Formation values (Hf)|Stream Heat of Formation values (Hf)]] for an example of how these individual heats of formation are used to determine the heat of formation of a stream.

'''Notes:'''
# All elements in their Standard State should have zero heat of formation at 25 °C.
#* Examples of elements in their standard state: O2(g), N2(g), C(s) - where C is graphite.
# H+(aq) should have zero heat of formation at 25 °C. Projects with H+(aq) which use a non-zero value will not load.

The image below shows the dialog box for the User values of H25:

[[Image:Species Editing H25 1.png]]

* For most species, the user will enter a single Constant Value.
* However, in some cases, especially for acids or bases, the user may prefer to enter a range of H25 values for different mass fractions in solution. This allows SysCAD to then calculate the energy released or absorbed when solutions of different mass concentrations are mixed. This is discussed in the section below:

=== Heat of Formation (H25) with Heat of Dilution Correction ===

When the concentration of some aqueous solute species in a solution are changed there can be a significant change in the enthalpy of those species. While this effect is usually negligible for most solutes, it is important for strong acids or bases. The most well known example of this effect is diluting concentrated sulfuric acid with water - this is highly exothermic and can result in a large temperature increase of the resulting solution.

The Heat of Formation data entered with the Heat of Dilution correction will enable SysCAD to calculate the heat of formation of a species in solution taking into account the effect of heat of dilution (the energy released or absorbed when the concentration of that species is changed). This is important for calculating the change in temperature associated with dilution or concentration of that species and also for calculating the heat of reaction if that species is formed or consumed by chemical reactions or phase change.

NB it is important to note that the enthalpy data entered into SysCAD for that species ''must'' include the heat of formation of the aqueous species at infinite dilution - this term is typically much larger than the effect of changing concentration. If this term is left out, calculation of the heat of reaction for any reaction involving this species will be grossly in error (including simple phase change without chemical reaction).

Heat of dilution data is often presented in different formats and is frequently given in a table as the difference in enthalpy between the species at some concentration and at infinite dilution. In this format, it does not include the heat of formation at infinite dilution and that must then be added into the data before entry into SysCAD.

An example is given here for hydrochloric acid, HCl(aq). If the concentration of the HCl(aq) in the solution is changed, the heat of formation will change. Data for the ''heat of dilution'' is in the table below. The data, -dHdil column, is given as the negative of the amount of heat released when a solution at the given concentration is diluted to infinite dilution so that value should be added to the heat of formation at infinite dilution to get the heat of formation at the given concentration. The heat of formation of HCl(aq) at infinite dilution is -166.99 kJ/mol and the data in the right most column are the heats of formation at the given concentrations that calculated by adding the heat of dilution to the heat of formation.

[[File:HCl_dat2.jpg]]

The ''heat of formation data'' in the right most column can be curve fit as a function of mass fraction or the entered as a table and have SysCAD fit a cubic spline to the data. It is important that when doing the curve fit that the entire range of possible concentrations is covered - i.e. from 0% to 100% solute. Even though the solution may never reach that concentration, it is important to cover the full range for numerical stability. Higher order curves fits are often required to match the data and stepping even slightly outside of the data range can result in unpredictable results. In the example here, the original data only go to 66.9% mass fraction HCl so we extrapolated to 100% using the last two data points.

[[File:HCl Plot.jpg]]

'''Notes:'''
# A polynomial will be processed more quickly within SysCAD and hence is preferred to a table of data.
# If you use a table of data (Spline under Tension), you must have data points for the mass fraction of the species at 0 and 100%.
# The best way to enter the table of values, is to have the data in an Excel spreadsheet in 2 adjacent columns - the first containing the Mass Fraction, and the second with the H25. Copy the 2 columns of data and paste them into the table in SysCAD. See the image below:
#:[[Image:Species Editing Heat of Dilution.png]]

=== Heat of Transition ===

If the heat capacity range for a species does not include 25 °C (298.15K), then the enthalpy at the starting temperature of the heat capacity range (Ts) will be calculated as follows:

<math> H (Ts) = H_f (298.15K) + C_p \times (Ts - 298.15) </math>

where Cp is the heat capacity at Ts.

Thus if the enthalpy at Ts is known, the user can calculate what Hf should be entered in order to achieve this enthalpy in SysCAD.

This is similar to what SysCAD does automatically when importing species data from the HSC Database (refer to [[Importing_Species_into_User_Species_Database#Importing_Species_with_Phase_Change_From_HSC|Importing Species from HSC Database]]).

== Entropy (S25) ==

This field is '''optional'''.

This is the ''absolute'' entropy value for the species at reference temperature. The unit for Entropy is J/mol.K.

For some Cp correlations, for example NASAGlenn_Cp and Gibbs_Cp, the value for S25 can be calculated directly from the Cp equation parameters. The user can then enter "FromCp()" which tells SysCAD to calculate the value for S25 for the entropy equation from the selected Cp equation. When selecting these types of Cp correlations and there are inconsistencies between the entered S25 and calculated S25 an error is given. This is new to Build 138.

Entropy values are normally only used in Free Energy Minimisation (FEM) or adiabatic (isentropic) calculations. For isentropic calculation (e.g. compressor or turbine models), only ''differences'' in entropy are used, so this value need not be specified. However for FEM calculations, the absolute entropy is required and this value must be provided.

For gases (except steam), as well as integrating Cp/T with respect to temperature, a pressure term is included:
:-R * ln(P/Po)
:where R = gas constant
:::P = partial pressure
:::Po = reference pressure (1 atm)

Steam entropy is also a function of both temperature and pressure.

Refer to [[Stream Properties using Standard Method#Stream Entropy values (S)|Stream Entropy (S)]] for an example of how these individual entropies are used to determine the entropy of a stream.

'''Note:''' H+(aq) should have zero entropy at 25 °C. Projects with H+(aq) which use a non-zero value will not load.

File:HCl plot.jpg

2025-08-07T21:52:45Z

John.McFeaters:

Species Table - Thermodynamic Data

2025-08-07T20:49:03Z

John.McFeaters: /* Heat of Dilution */

[[Category:Species]] [[Category:Properties]] [[Category:Energy]]
{{Navigation|[[User Guide]]|[[Species Table]]|altname=Thermodynamic Data}}
{{Species Database Header tabs | currentpage=5}}
----
{{TOC}}
== Introduction ==

This is information is generally required for all species, unless the project is not using the Energy Balance Add-On and/or with Heat Calculations switched off.

'''Notes:'''
# Species that have been added to represent gangue material, such as Inerts, Ore, etc. will generally not have any thermodynamic data.
# When importing Species from the HSC database that have a structural change at temperature, for example solids in smelters or furnaces where they change between alpha and beta states, SysCAD manipulates the Heat of Formation to take the enthalpy of phase change into account. Please see '''[[Importing Species into User Species Database#Importing_Species_from_HSC_Database|Importing Species from HSC Database]]'''.

== Heat of Formation (H25) ==

This field is '''optional''' (but is usually defined).

This is the Heat of Formation at 25 °C. The unit is expressed in J/mol.

If this field is left blank, SysCAD will assume a value of 0 J/mol at 0°C.

For some Cp correlations, for example NASAGlenn_Cp and Gibbs_Cp, the value for H25 can be calculated directly from the Cp equation parameters. The user can then enter "FromCp()" which tells SysCAD to calculate the value for H25 for the enthalpy equation from the selected Cp equation. When selecting these types of Cp correlations and there are inconsistencies between the entered H25 and calculated H25 an error is given.

This value is used to calculate heats of reaction for chemical reactions specified in SysCAD. If the compound is used in chemical reactions, this number will determine the accuracy of the energy balance. If this field is left blank due to lack of data, then the user should define the Heat of Reaction (HOR) manually in the reaction file. See '''[[Reaction Block (RB)]]''' for further information on reactions.

Refer to [[Stream Properties using Standard Method#Stream Heat of Formation values (Hf)|Stream Heat of Formation values (Hf)]] for an example of how these individual heats of formation are used to determine the heat of formation of a stream.

'''Notes:'''
# All elements in their Standard State should have zero heat of formation at 25 °C.
#* Examples of elements in their standard state: O2(g), N2(g), C(s) - where C is graphite.
# H+(aq) should have zero heat of formation at 25 °C. Projects with H+(aq) which use a non-zero value will not load.

The image below shows the dialog box for the User values of H25:

[[Image:Species Editing H25 1.png]]

* For most species, the user will enter a single Constant Value.
* However, in some cases, especially for acids or bases, the user may prefer to enter a range of H25 values for different mass fractions in solution. This allows SysCAD to then calculate the energy released or absorbed when solutions of different mass concentrations are mixed. This is discussed in the section below:

=== Hf(25) with Heat of Dilution Correction ===

When the concentration of some aqueous solute species in a solution are changed there can be a significant change in the enthalpy of those species. While this effect is usually negligible for most solutes, this is important for strong acids or bases. The most well known example of this effect is diluting concentrated sulfuric acid with water - this is highly exothermic and can result in a large temperature increase of the resulting solution.

The Heat of Formation data entered with the Heat of Dilution correction will enable SysCAD to calculate the heat of formation of a species in solution taking into account the effect of heat of dilution (the energy released or absorbed when the concentration of that species is changed). This is important for calculating the change in temperature associated with dilution or concentration of that species and also for calculating the heat of reaction if that species is formed or consumed by chemical reactions or phase change.

NB it is important to note that the enthalpy data entered here ''must'' include the heat of formation of the aqueous species at infinite dilution - this term is typically much larger than the effect of changing concentration. If this term is left out, calculation of the heat of reaction for any reaction involving this species will be grossly in error (including simple phase change without chemical reaction).

Heat of dilution data is often presented in different formats and is frequently given in a table as the difference in enthalpy between the species at some concentration and at infinite dilution. In this format, it does not include the heat of formation at infinite dilution and that must then be added into the data before entry into SysCAD.

An example is given here for HCl(aq).

*The heat of formation of HCl(aq) at infinite dilution is -166.99 kJ/mol.
If the concentration of the HCl(aq) in the solution is changed, the enthalpy will change. Data for the ''heat of dilution'' is on the table below;

[[File:HCl_dat2.jpg]]

HCL Data File

'''Notes:'''
# A polynomial will be processed more quickly within SysCAD and hence is preferred to a table of data.
# If you use a table of data (Spline under Tension), you must have data points for the mass fraction of the species at 0 and 100%.
# The best way to enter the table of values, is to have the data in an Excel spreadsheet in 2 adjacent columns - the first containing the Mass Fraction, and the second with the H25. Copy the 2 columns of data and paste them into the table in SysCAD. See the image below:
#:[[Image:Species Editing Heat of Dilution.png]]

=== Heat of Transition ===

If the heat capacity range for a species does not include 25 °C (298.15K), then the enthalpy at the starting temperature of the heat capacity range (Ts) will be calculated as follows:

<math> H (Ts) = H_f (298.15K) + C_p \times (Ts - 298.15) </math>

where Cp is the heat capacity at Ts.

Thus if the enthalpy at Ts is known, the user can calculate what Hf should be entered in order to achieve this enthalpy in SysCAD.

This is similar to what SysCAD does automatically when importing species data from the HSC Database (refer to [[Importing_Species_into_User_Species_Database#Importing_Species_with_Phase_Change_From_HSC|Importing Species from HSC Database]]).

== Entropy (S25) ==

This field is '''optional'''.

This is the ''absolute'' entropy value for the species at reference temperature. The unit for Entropy is J/mol.K.

For some Cp correlations, for example NASAGlenn_Cp and Gibbs_Cp, the value for S25 can be calculated directly from the Cp equation parameters. The user can then enter "FromCp()" which tells SysCAD to calculate the value for S25 for the entropy equation from the selected Cp equation. When selecting these types of Cp correlations and there are inconsistencies between the entered S25 and calculated S25 an error is given. This is new to Build 138.

Entropy values are normally only used in Free Energy Minimisation (FEM) or adiabatic (isentropic) calculations. For isentropic calculation (e.g. compressor or turbine models), only ''differences'' in entropy are used, so this value need not be specified. However for FEM calculations, the absolute entropy is required and this value must be provided.

For gases (except steam), as well as integrating Cp/T with respect to temperature, a pressure term is included:
:-R * ln(P/Po)
:where R = gas constant
:::P = partial pressure
:::Po = reference pressure (1 atm)

Steam entropy is also a function of both temperature and pressure.

Refer to [[Stream Properties using Standard Method#Stream Entropy values (S)|Stream Entropy (S)]] for an example of how these individual entropies are used to determine the entropy of a stream.

'''Note:''' H+(aq) should have zero entropy at 25 °C. Projects with H+(aq) which use a non-zero value will not load.

File:HCl dat2.jpg

2025-08-07T20:46:32Z

John.McFeaters: John.McFeaters uploaded a new version of File:HCl dat2.jpg

== Summary ==
HCl heat of dilution

File:HCl dat2.jpg

2025-08-07T20:12:06Z

John.McFeaters: HCl heat of dilution

== Summary ==
HCl heat of dilution

File:HCl dat.jpg

2025-08-07T20:03:21Z

John.McFeaters: John.McFeaters uploaded a new version of File:HCl dat.jpg

== Summary ==
HCl Heat of dilution

File:HCl dat.jpg

2025-08-07T19:56:05Z

John.McFeaters: John.McFeaters uploaded a new version of File:HCl dat.jpg

== Summary ==
HCl Heat of dilution

File:HCl dat.jpg

2025-08-07T18:37:40Z

John.McFeaters: John.McFeaters uploaded a new version of File:HCl dat.jpg

== Summary ==
HCl Heat of dilution

File:HCl dat.jpg

2025-08-07T17:16:51Z

John.McFeaters: HCl Heat of dilution

== Summary ==
HCl Heat of dilution

Template:LL Tab page Data sections

2024-10-16T17:46:08Z

John.McFeaters:

This page is only visible if the Level Lookup option is chosen.

'''Notes:'''
# The volume of material in the {{{UnitOp}}} is measured from the actual mass and density. This is the value used in the lookup tables to determine the corresponding Height, and hence Level, and if required the corresponding Surface Area.

{| border="1" cellpadding="5" cellspacing="0"
|-
! '''Tag (Long/Short)'''|| '''Input / Calc'''|| '''Calculated Variables / Options'''
|-
|font style="background: #ebebeb" colspan="3" | '''LL (Lookup Level)'''
|-
| Count || Input || The number of data points - this will determine the number of rows in the Lookup Table described below.
|-
| WithSurfArea || Tick Box || Allows user to also specify the Surface Area as a function of Volume in the {{{UnitOp}}}.
|-
| SortAndCheck ||font style="background: #ebebeb"| Button || Sorts data in ascending order by Volume. Corrects inconsistent data.
|-
| Volume ||font style="background: #ebebeb"| Display|| The Volume of material in the {{{UnitOp}}}.
|-
| Level / Lvl ||font style="background: #ebebeb"| Display|| The Level of the {{{UnitOp}}} based on the current volume in the {{{UnitOp}}} and the lookup tables.
|-
| Height ||font style="background: #ebebeb"| Display|| The Height in the {{{UnitOp}}} based on the current volume in the {{{UnitOp}}} and the lookup tables.
|-
| Area ||font style="background: #ebebeb"| Display|| The Surface Area of the {{{UnitOp}}} contents based on the current volume in the {{{UnitOp}}} and the lookup tables. This is only visible if ''WithSurfArea'' is enabled.
|-
|font style="background: #ebebeb" colspan="3" | The Lookup table is displayed, with the number of rows as defined by ''Count''.
|-
| font style="background: #ebebeb" | ''Volume'' || Column Heading|| The Volume in the {{{UnitOp}}} for data point X.
|-
| font style="background: #ebebeb" | ''Height'' || Column Heading || The height of the slurry in the {{{UnitOp}}} corresponding to the volume in column 1.
|-
| font style="background: #ebebeb" | ''Area'' || Column Heading || (only visible if the user has ticked ''WithSurfArea'') The surface area of the {{{UnitOp}}} corresponding to the Volume in column 1.
|}

Hydrocyclone

2024-08-22T18:33:20Z

John.McFeaters: /* Plitt Cyclone Model */

[[Category:Models]] [[Category:Size Distribution]]
{{Navigation|[[Models]]|[[Models#Size Distribution Models|Size Distribution Models]]}}

----
{{TOC}}
== General Description ==

This model is used to simulate either a single Hydrocyclone, or a cluster of Hydrocyclones.

The model is primarily designed to split solids based on size distribution data. Therefore, the feed should contain solids with size distribution information. The model will calculate the split of solids between the under and over flows based on the cut point (either calculated or defined) and the size distribution of the feed stream.

Using Size Distribution, the unit allows the user to define the cyclone in one of five ways:
# Define the partition curve of the cyclone
# Define the cut point, d<sub>50</sub>, of the cyclone
# Use the Krebs method to calculate the cut point
# Use the Plitt method to calculate the cut point
# Use the Nageswararao method to calculate the cut point

The first two options allow the user to set the cut point without any further knowledge of the cyclone. The next three options require the user to define the cyclone dimensions. These dimensions are then used to calculate the cut point and partition curve of the cyclone.

In the case of the Plitt and Nageswararao methods, the model will also calculate the liquid split between the over and under flows.

The Hydrocyclone may also act as a simple splitter, where the solids in the feed to the unit do not have any size distribution data. In this case the user must select Method = 'Simple (non PSD) Models' and set the solids and liquid split to the under and over flow streams.

'''Note:'''
This unit cannot be used to model a gas cyclone.

== Diagram ==

[[Image:Models-Cyclone-Image003.gif]]

The diagram shows the default drawing of the Hydrocyclone, with all of the streams that are required for operation of the unit.

The physical location of the streams connecting to the Hydrocyclone is unimportant. The user may connect the streams to any position on the unit.

== Inputs and Outputs ==

{| border="1" cellpadding="5" cellspacing="0"
|-
| valign="top" rowspan="2" | '''Label''' || valign="top" rowspan="2" | '''Required<br>Optional''' || valign="top" rowspan="2" | '''Input<br>Output ''' || colspan="2" | '''Number of Connections''' || valign="top" rowspan="2" | '''Description'''
|-
| '''Min''' || '''Max'''
|-
| Feed || Required || In || 1 || 20 || The slurry feed to the Hydrocyclone
|-
| OverFlow || Required || Out || 1 || 1 || The over flow from the unit
|-
| UnderFlow || Required || Out || 1 || 1 || The under flow from the unit
|}

== Model Theory ==

{|
|-
|[[Image:ng1.png | 350px]]
|Valign=top|The method of splitting the solids based on Size Distribution data is discussed below:

# The model will simulate a Hydrocyclone using one of the five user defined methods - 'User Defined Curves', 'User d<sub>50</sub>', 'Krebs Cyclone', 'Plitt Cyclone' and 'Nageswararao'. These are described below.
# The 'User Defined Curves' method allows the user to define the fraction of material in each size interval that will report to the cyclone overflow.
# The other methods use the d<sub>50</sub> value, either calculated or defined by the user, to determine the solids separation. The d<sub>50</sub> is defined as the particle size that has a 50% chance of reporting to either the cyclone underflow or overflow. The majority of the particles finer than this size will report to the overflow, while the majority of those coarser will report to the cyclone underflow.
# The user may also define the number of Hydrocyclones in the cluster. The default value, and the minimum number, is 1. This allows the model to calculate the pressure drop across each cyclone by dividing the flow to the model by the number of cyclones in the cluster. This allows the user to model a number of Hydrocyclones with a single drawing.

The drawing to the left shows the dimensions that are used in the Plitt and Nageswararao models.

* The Plitt model doesn't include the length of the cylindrical section as a parameter
* The length <math>h</math> is the ''free vortex height'', i.e. the distance from the underflow to the bottom of the vortex finder.
* In the Nagasawarao model, the height <math>h</math> is implicitly calculated from the cone angle and the diameters assuming the free vortex occupies the conical section.
|}
=== User Defined Curves (Efficiency Curve) ===
{|
|-
|[[Image:EfficiencyCurve.jpg]]
|Valign=top|The user defines the Efficiency Curve of the cyclone by entering the fraction of material in each size interval that will report to the cyclone overflow. This will normally be the Actual efficiency curve, which takes into account the bypassing of fines to the underflow with the liquid.

An example of an Efficiency curve is shown to the left.

The user also defines the fraction of solids in the Cyclone underflow, as this allows the model to calculate the liquid split across the cyclone.
|}
=== User d50 ===

The user defines the cut point of the cyclone, the d<sub>50</sub>, the Efficiency Curve Split Method and the required percentage solids in the under flow from the unit.

The model then uses the d<sub>50</sub> defined by the user and the selected Efficiency Curve Split Method to calculate the fraction of solids in each size interval reporting to the underflow.

=== Krebs Cyclone Model ===

The user defines the cyclone diameter, the percentage solids in the cyclone under flow, a correction factor for the cyclone geometry, if necessary and the Efficiency Curve Split Method.

The model calculates the d<sub>50</sub> of the cyclone from the following equations<sup>'''2'''</sup>:

(1) <math>d_{50}=d_{50}(Base)\times C_1\times C_2\times C_3\times Factor</math>

where ''Factor'' is a correction factor to account for differences in the cyclone geometry from the 'optimum' dimensions.

(2) <math>d_{50}(Base)=2.84\times D_c^{0.66}</math>

{| border="0" cellspacing="0" cellpadding="1"
|-
|rowspan="2" valign="top" | where: || d<sub>50</sub>(Base) || = the cut size a "standard cyclone" can achieve, in microns.
|-
| Dc || = cyclone diameter, in cm
|}

(3) <math>C_1=\begin{pmatrix}\cfrac{53-C_v}{53}\end{pmatrix}^{-1.43}</math>

{| border="0" cellspacing="0" cellpadding="1"
|-
|rowspan="2" valign="top"| where: || C<sub>1</sub> || = Correction for the influence of cyclone feed concentration
|-
| C<sub>v</sub> || = Feed solids volume concentration (%) at Feed T and Pressure
|}

(4) <math>C_2=3.27\times \boldsymbol{\Delta}P^{-0.28}</math>

{| border="0" cellspacing="0" cellpadding="1"
|-
|rowspan="2" valign="top"| where: || C<sub>2</sub> || = Correction for the influence of pressure drop
|-
| DP || = Pressure drop across the cyclone in kPa - calculated in (5) using Plitt method
|}

(5) <math>\boldsymbol{\Delta}P=\cfrac{1.88\times Q^{1.78}\times exp(0.0055\times C_v)}{D_c^{0.37}\times D_i^{0.94}\times h^{0.28}\times (D_u^2+D_o^2)^{0.87}}</math>

{| border="0" cellspacing="0" cellpadding="1"
|-
|valign="top" rowspan="7"| where: || Q || = feed slurry volumetric flow-rate per cyclone in l/min
|-
| C<sub>v</sub> || = Feed solids volume concentration (%) at 25 dC and 101.325 kPa abs.
|-
| D<sub>C</sub> || = Diameter of cyclone
|-
| D<sub>I</sub> || = Diameter of cyclone inlet = 0.2 * D<sub>C</sub>
|-
| D<sub>U</sub> || = Diameter of cyclone underflow, or apex = 0.15 * D<sub>C</sub>
|-
| D<sub>O</sub> || = Diameter of cyclone overflow, or vortex finder = 0.3 * D<sub>C</sub>
|-
| h || = Free vortex height of cyclone = 1.5 * D<sub>c</sub>
|}

{| border="0" cellspacing="0" cellpadding="1"
|-
| All the cyclone dimensions are in cm. These values are for an 'Optimum Cyclone'<sup> '''2''' </sup>.
|}

(6) <math>\mathbf{\mathit{C_3=\begin{pmatrix}\cfrac{1.65}{G_S-G_L}\end{pmatrix}^{0.5}}}</math>

{| border="0" cellspacing="0" cellpadding="1"
|-
| rowspan="4" valign="top" | where:
|-
| C<sub>3</sub> || = Correction for the influence of SG
|-
| G<sub>S </sub> || = SG of solids
|-
| G<sub>L </sub> || = SG of liquids
|}

{| border="0" cellspacing="0" cellpadding="1"
|-
| The model then uses the d<sub>50</sub>, either defined as in 4.1 or calculated in 4.2, to calculate the fraction of solids in each size range using the following equations <sup>'''2,3'''</sup>:
|}

:<math>x=\cfrac{Particle_-diameter}{d_{50}}</math>

: where Particle_diameter - geometric mean of the size interval

:<math>y^1=\cfrac{\exp(4x)-1}{\exp(4x)+\exp(4)-2}</math>

:{|
|-
|valign="top" | where: || y || = recovery to underflow on a corrected basis
|}

:<math> y=y^1 +R_f (1-y^1)</math>
:{|border="0" cellspacing="0" cellpadding="1"
|-
|valign="top" rowspan="2"| where: || y || = actual recovery to underflow
|-
| R<sub>f</sub> || = fraction of feed liquid reporting to the underflow product
|}

'''Assumptions (Krebs)'''

# The cyclone has 'optimum' dimensions, as given in equation 5 above.
# The mass weighted mean of the solids density is used to determine the cut point.

'''Note:''' Due to equation (3), Cv (feed solids volume concentration) must be less than 53%.

=== Plitt Cyclone Model ===

The user defines all of the cyclone dimensions and the model then calculates the d<sub>50</sub> in microns, the pressure drop across the cyclone and the liquid distribution between the over and under flows.

The following equations are used to determine the cyclone operation<sup>4</sup><nowiki>:</nowiki>

(7) d<sub>50</sub> Calculation

<math>{d_{50}=F\left[\cfrac{50.5\times D_c^{0.46}D_i^{0.6}D_o^{1.21}\exp(0.063C_v)}{D_u^{0.71}h^{0.38}Q^{0.45}(\rho_s-\rho_l)^{0.5}}\right]}</math>

where d<sub>50</sub> is in microns

:D<sub>c</sub>- Cyclone diameter, cm

:D<sub>i</sub> - Cyclone feed inlet diameter, cm

:D<sub>o</sub>- Cyclone overflow or Vortex finder diameter, cm

:D<sub>u</sub>- Cyclone underflow or Apex diameter, cm

:h - Free vortex height in cyclone, cm

:Q - Volumetric flow rate of each cyclone feed at temperature,l/min

:C<sub>v</sub> - Volumetric percent of solids in feed slurry at temperature

:<math>\rho_s</math> - Solids density at Temperature (t/m<sup>3</sup>)

:<math>\rho_l</math> - Liquid density at Temperature (t/m<sup>3</sup>)

:F - d<sub>50</sub> correction factor.

(8) Pressure Drop across the Cyclone in kPa

:<math> \Delta P =PressFactor\times\cfrac{1.88Q^{1.78}\exp(0.0055C_v)} {D_{c}^{0.37}D_{i}^{0.94}h^{0.28}(D_u^2+D_o^2)^{0.87} }</math>

:where PressFactor - Pressure drop correction factor

(9) Pressure drop across cyclone, in metres of feed slurry

:<math>H=\cfrac{\Delta P}{g\rho_{Feed}}</math>

(10) Recovery of feed volume to the underflow product

:<math>R_v=\cfrac{S}{S+1}</math>

:where

:<math>S = SFactor* \cfrac{1.9 \left(\cfrac{D_u}{D_o} \right)^{3.31}h^{0.54}(D_u^2+D_o^2)^{0.36}*exp(0.0054C_v)} {H^{0.24}D_c^{1.11}}</math>

:where SFactor - S correction factor

(11) Sharpness Separation

<sub> <math>\mathbf{\mathit{m=SharpFactor*1.94*exp(-1.58*R_v)*\left(\cfrac{D_c^2*h}{Q} \right)^{0.15}}}</math> </sub>

For backward compatibility when ''OldSharpnessCalc'' is selected, Plitt sharpness term is calculated as

<sub> <math>\mathbf{\mathit{m=SharpFactor*1.94*exp\left[(-1.58*R_v)*\left(\cfrac{D_c^2*h}{Q} \right)^{0.15}\right]}}</math> </sub>

where: R<sub>v</sub> - Recovery of feed volume to the underflow product

:SharpFactor - Sharpness correction factor

:Q - Volumetric flow rate of each cyclone feed at temperature, l/min

The Separation Sharpness, ''m'', is the sharpness parameter used in the Rosin-Ramler separation efficiency curve. The separation sharpness parameter, <math>{\alpha}</math>, used in the Lynch separation efficiency curve can be found from ''m'' by (see ''[[#Hydrocyclone Page|Efficiency Curves]]'' below).

:<math>{{{\alpha}=1.54*m - 0.47}}</math>

'''Assumptions (Plitt)'''

# The pressure drop equation assumes free discharge from both the under and over flows from the cyclone.
# The mass weighted mean of the solids density is used to determine the cut point.
# Q in the sharpness equation is the total volumetric flow into the cyclones.

=== Nageswararao Model ===

The user defines all of the cyclone dimensions and the model then calculates the d<sub>50</sub> in microns, the pressure drop across the cyclone and the liquid distribution between the over and under flows.

The following equations are used to determine the cyclone operation<sup>5</sup><nowiki>:</nowiki>

(12) Cyclone Throughput:

:<math>{\cfrac{Q}{D_c^{2}\sqrt{P/\mathit{\rho_p}}} = K_{Qo}D_c^{-0.10} \left(\cfrac{D_o}{D_c} \right)^{0.68} \left(\cfrac{D_i}{D_c} \right)^{0.45} \left(\cfrac{L_c}{D_c} \right)^{0.20}\mathit{\Theta^{-0.10}}}</math>

:where D<sub>c</sub> - Cyclone diameter, cm
:D<sub>i</sub> - Cyclone feed inlet diameter, cm
:D<sub>o</sub> - Cyclone overflow or Vortex finder diameter, cm
:K<sub>Qo</sub> - Material dependent constant for performance characteristic, P<sub>i</sub>
:L<sub>c</sub> - Length of the cylindrical section of the cyclone, cm
:P - Cyclone feed pressure, kPa
:Q - Cyclone throughput, l/min
:<math>\mathbf{\mathit{\Theta}}</math> - full cone angle, degrees

(13) d<sub>50c</sub> Calculation

<math>{\cfrac{d_{50c}}{D_c}=K_{Do} \left(D_c^{-0.65} \right) \left(\cfrac{D_o}{D_c} \right)^{0.52} \left(\cfrac{D_u}{D_c}\right)^{-0.50} \left(\cfrac{D_i}{D_c}\right)^{0.20} \left(\cfrac{L_c}{D_c} \right)^{0.20}\mathit{\Theta^{0.15}} \left(\cfrac{P}{\mathit{\rho_p}gD_c} \right)^{-0.22}\mathit{\lambda^{0.93}}}</math>

where d<sub>50c</sub> is the corrected cut size in microns

:D<sub>u</sub> - Cyclone underflow or spigot diameter, cm
:g - acceleration due to gravity, m/s<sup>2</sup>
:K<sub>Do</sub> - Material dependent constant for performance characteristic, P<sub>i</sub>
:<math>\rho_p</math> - Density of feed pulp, (t/m<sup>3</sup>)
:<math>\lambda</math> - hindered settling factor

Nageswararao Hindered Settling Factor:
:<math>{\lambda = \cfrac{10^{1.82C_v}}{8.05\times(1-C_v)^{2}}}</math>

Richardson Zaki Settling Factor:
:<math>{\lambda = (1-C_v)^{2.39}}</math>
:: C<sub>v</sub> - Volumetric fraction of feed solids.

(14) Recovery of water to the underflow product

:<math>{R_f = K_{Wo}\left(D_c^{-0.00}\right)\left(\cfrac{D_o}{D_c}\right)^{-1.19}\left(\frac{D_u}{D_c}\right)^{2.40}\left(\cfrac{D_i}{D_c}\right)^{-0.50} \left(\cfrac{L_c}{D_c}\right)^{0.22} \mathit{\Theta^{-0.24}}\left(\cfrac{P}{\mathit{\rho_p}gD_c}\right)^{-0.53}\mathit{\lambda^{0.27}}}</math>

:where K<sub>Wo</sub> - Material dependant constant for performance characteristic, P<sub>i</sub>

'''Assumptions (Nageswararao)'''
# The pressure drop equation assumes free discharge from both the under and over flows from the cyclone.
# The mass weighted mean of the solids density is used to determine the cut point.
# Q is the total volumetric flow into the cyclones.

=== Efficiency Curves ===

If the user selects the User d<sub>50</sub>, Krebs, Plitt or Nageswararao models, they may choose the Efficiency Curve equation that will be used to calculate the solids size distribution across the cyclone.

The common forms of the Efficiency Curves are the Rosin-Rammler and Lynch curves. However, these have the disadvantage of not being able to model the "fishhook" since they are monotonic. Each has a single "sharpness" parameter - as the sharpness increases, the separation about the d<sub>50</sub> increases. (d<sub>50</sub> is the size which will report with equal probability to underflow or overflow, and refers to the ''corrected'' value.)

The Whiten Fishhook Efficiency curve has 2 further parameters that allow it to model the "fishhook". Furthermore, this method models the actual recovery, rather than the corrected recovery.

Note that the efficiency curve is ''not'' the actual recovery curve (the split between underflow and overflow). Hydrocyclone models assume that the fine particles do not separate, so that they effectively partition with the liquid, so that the recovery for fine particles is the same as the liquid split <math>R_f</math>. This means that the recovery curve is related to the efficiency curve by <math>{{y=y'+R_f(1-y')}}</math>

==== Rosin-Rammler ====

(15) Recovery to underflow on a corrected basis for the size interval. This method is based on a Rosin-Rammler type of function with the efficiency curve expression derived by Reid and Plitt.

:<math>{y_i'=1-\exp\left[-0.693147\times\left(\cfrac{d_i}{d_{50}}\right)^m\right]}</math>

where di - geometric mean of the size interval
:m - measure of the sharpness of separation.

[[File:Cyclone Eff Curve RR.png]]

==== Lynch ====

(16) Recovery to underflow on a corrected basis for the size interval

:<math>{{y_i'=\cfrac{\exp\left(\alpha d_i/d_{50}\right)-1}{\exp\left(\alpha d_i/d_{50}\right)+\exp(\alpha)-2}}} </math>

where: d<sub>i</sub> - geometric mean of the size interval

:<math>{\alpha}</math> = measure of the sharpness of separation

[[File:Cyclone Eff Curve Lynch.png]]

(17) The actual recovery to the underflow, y, is then calculated using the same equation for both of the above methods:

:<math>{{y=y'+R_f(1-y')}}</math>

where R<sub>f</sub> = fraction of feed liquid reporting to the underflow product.

==== Whiten Fishhook ====

The Whiten Fishhook curve has further parameters that allow it to model the "fishhook".

(18) This is the ''actual'' rather than corrected curve:

:<math>y_i=1 - \cfrac{\exp({\alpha})-1}{\exp \left(\alpha \beta^{*} \cfrac{d_i}{d_{50}} \right) + \exp ({\alpha})-2} \left(1+{\beta}{\beta^{*}} \cfrac{d_i}{d_{50}}\right) </math>

where: d<sub>i</sub> - geometric mean of the size interval

: <math>\alpha</math> determines the slope at the larger values of d.
: <math>\beta</math> controls the initial rise in the curve at fine sizes..
: <math>\beta^*</math> preserves the definition of d<sub>50</sub>.

[[File:cyclone05.png]][[File:cyclone06.png]]

====Notes====
The existence of the "fishhook" - where the recovery to underflow of solids initially decreases as the particle size increases - has been contentious until recently [6]; and the exact mechanisms are still uncertain. It is accepted as real now, but it is a subtle effect. If the underflow liquid recovery is too low in the SysCAD model, the fishhook effect may result in all solids in some size range report to the overflow (zero recovery) which is physically unrealistic. SysCAD will in this case set the PSD fractions to zero over this range, and report a warning that the underflow solids fraction is not achieved. In this case, either reduce the fishhook parameter <math>\beta</math> or the specified underflow solids.

[[File:cyclone08.png]]

====User Curve ====

The user may give actual curve data to specify the solids split. Either the actual or the corrected split may be specified. This is useful in several situations:

The user may have plant data, which they want to use to tune a particular model. Also, there are other efficiency curve models not presently implemented in SysCAD, such as the Cilliers model. The user could then calculate the solids partition using a PGM, or externally and supply this to the model.

Note that specifying the curve data effectively determines the d50 for the solids split. Some of the methods such as the Nagaswararo cyclone calculate the d50 - it is up to the user to ensure that the d50 for the specified split is equal to that calculated by the model (or at least understand that they are using a different d50.) SysCAD will display the d50 for the user curves, and this can be compared to the calculated d50.

=== References ===

# R.A.Arterburn, ''The Sizing and Selection of Hydrocyclones'', Metallurgical Handbook.
# D.T.Tarr, ''Practical application of liquid cyclones in mineral dressing problems'', Krebs Engineers documentation, October 1965.
# L.R.Plitt, ''A mathematical model of the hydrocyclone classifier'', CIM Bulletin, December 1976.
# T.P.Napier-Munn, ''Mineral Comminution Circuits: Their Operation and Optimisation'', JKMRC Monograph Series in Mining and Mineral Processing 2, 1999.
# K. Nageswararao, D.M. Wiseman, T.J. Napier-Munn, ''Two empirical hydrocyclone models revisited'', Minerals Engineering 17 671–687, 2004.
# Florent Bourgeois, Arun K. Majumder, ''Is the fish-hook effect in hydrocyclones a real phenomenon?'', Powder Technology, Volume 237, 2013

== Data Sections ==

The default sections and variable names are described in detail in the following tables. The default Hydrocyclone access window consists of 5 sections. This number may increase, based on user configuration.

=== Summary of Data Sections ===

# '''[[#Hydrocyclone Page|Hydrocyclone]]''' tab - Allows the user to select the Hydrocyclone method and displays a summary of the flows in the Feed, Overflow and Underflow streams.
# '''[[#Cyclone Page|Cyclone]]''' tab - This page contains all of the fields relating to the Hydrocyclone method.
# '''[[#Partition Curve Page|PartCrv]]''' tab - This tab displays the partition curve data for the cyclone.
# '''[[Material Flow Section|QFeed]]''' - Optional tab, only visible if ''ShowQFeed'' is enabled. This page shows the properties of the mixed stream as the feed to the Hydrocyclone model.
# '''[[Material Flow Section|QOFlow]]''' - Optional tab, only visible if ''ShowQOFlow'' is enabled. This page shows the properties of the overflow stream from the Hydrocyclone model.
# '''[[Material Flow Section|QUFlow]]''' - Optional tab, only visible if ''ShowQUFlow'' is enabled. This page shows the properties of the underflow stream from the Hydrocyclone model.
# '''[[Common Data Sections#Common Data on Info Tab Page|Info]]''' tab - Contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
# '''[[Links Table|Links]]''' tab, contains a summary table for all the input and output streams.
# '''[[Audit]]''' tab - Contains summary information required for Mass and Energy balance. See [[Model Examples]] for enthalpy calculation Examples.

=== Hydrocyclone Page===

'''Unit Type: Hydrocyclone''' - The first tab page in the access window will have this name.

{| border="1" cellpadding="5" cellspacing="0" align="center"
|'''Tag (Long/Short)'''||'''Input / Calc'''||'''Description/Calculated Variables / Options'''
{{Common Data on First Tab Page}}
|-
| colspan="3" font style="background: #ebebeb" | '''''Requirements'''''
|-
| On || Tickbox || This allows the user to Enable or Disable the unit. If the Hydrocyclone is disabled (turned OFF), then all of the material will flow out of the underflow stream.
|-
| rowspan="6" valign="top" | Method || Simple (no PSD) || The unit does not use, or require, the Size Distribution information to calculate solids split. The user defines the solids and liquids split on a simple mass fraction basis.
|-
|User Defined Curves|| The user specifies an [[#User Defined Curves (Efficiency Curve)|Efficiency Curve]] (or partition curve) on the [[#Partition Curve Page|Partition Curve]] page, which is used to calculate the separation of the solids. The user also specifies the fraction of solids in the Cyclone underflow. The model calculates the Actual d<sub>50</sub> of the cyclone and the liquid split to the under and over flows.
|-
| User d50 || The user specifies the actual d<sub>50</sub> of the cyclone, the required [[#Efficiency Curves|Efficiency Curve]] Split Method and the percent solids in the underflow.
|-
| Krebs Cyclone || The unit uses the [[#Krebs Cyclone Model|Krebs Cyclone Model]] to calculate the operating parameters of the cyclone. The user specifies the cyclone diameter and, the percent solids in the underflow and the required [[#Efficiency Curves|Efficiency Curve]] Split Method. The model calculates the d<sub>50</sub> of the cyclone. The feed solids volume concentration must be greater than 53% to use this method.
|-
| Plitt Cyclone || The unit uses the [[#Plitt Cyclone Model|Plitt Cyclone Model]] to calculate the operating parameters of the cyclone. The user specifies the all of the physical parameters of the cyclone and the required [[#Efficiency Curves|Efficiency Curve]] Split Method. The model calculates the d<sub>50</sub> of the cyclone and the liquid split to the under and over flows.
|-
| Nageswararao || The unit uses the [[#Nageswararao Model|Nageswararao Model]] to calculate the operating parameters of the cyclone. The user specifies the all of the physical parameters of the cyclone and the required [[#Efficiency Curves|Efficiency Curve]] Split Method. The model calculates the d<sub>50</sub> of the cyclone and the liquid split to the under and over flows.
|-
| colspan="3" font style="background: #ebebeb" | ''Predictive Models for which all properties are calculated.''
|-
| colspan="3" font style="background: #ebebeb" | '''''Options'''''
|-
| ShowQFeed || Tickbox || Allows the user to display the properties of the feed streams to the Cyclone is a single Feed stream.
|-
| ShowQOFlow || Tickbox || Allows the user to display the properties of the overflow streams from the Cyclone.
|-
| ShowQUFlow || Tickbox || Allows the user to display the properties of the underflow streams from the Cyclone.
|-
| SizeForPassingFracCalc || Input || The particle size to be used for the percent 'Passing' display for '''ALL''' units in the Project.
|-
| FracForPassesSizeCalc || Input || The fraction percent passing to be used for the 'Passes' display for '''ALL''' units in the Project.
|-
| Intervals || [[image:Sz Ascending button.png]] <br> [[image:Sz Descending button.png]] || The user may toggle between displaying the size intervals ascending or descending.
|-
| colspan="3" font style="background: #ebebeb" | '''''Results'''''
|-
| DistributionUsed || font style="background: #ebebeb" |Display || Displays the size distribution used. (useful for projects containing multiple size distributions)
|-
| colspan="3" font style="background: #ebebeb" | '''''Stream Result Summary'''''<br>This table shows the following variables for the Feed, Underflow and Overflow streams.
|-
| MassFlow / Qm || font style="background: #ebebeb" | Display || The total mass flow in each stream.
|-
| SolidMassFlow / SQm || font style="background: #ebebeb" | Display || The Solids mass flow in each stream.
|-
| LiquidMassFlow / LQm || font style="background: #ebebeb" | Display || The Liquid mass flow in each stream.
|-
| VolFlow / Qv || font style="background: #ebebeb" | Display || The total Volume flow in each stream.
|-
| Temperature / T || font style="background: #ebebeb" | Display || The Temperature of each stream.
|-
| Density / Rho || font style="background: #ebebeb" | Display || The Density of each stream.
|-
| SolidFrac / Sf || font style="background: #ebebeb" | Display || The Solid Fraction in each stream.
|-
| LiquidFrac / Lf || font style="background: #ebebeb" | Display || The Liquid Fraction in each stream.
|-
| Passing || font style="background: #ebebeb" | Display || The mass fraction passing the user specifies size (in the field 'SizeForPassingFracCalc') in each stream.
|-
| Passes || font style="background: #ebebeb" | Display || The user specified (in the field 'FracForPassesSizeCalc') fraction of material in each stream will pass this size fraction.
|}

=== Cyclone Page ===

{| border="1" cellpadding="5" cellspacing="0" align="center"
|'''Tag (Long/Short)'''||'''Input / Calc'''||'''Description/Calculated Variables / Options'''
|-
| colspan="3" font style="background: #ebebeb" | '''''Requirements'''''
|-
| CyclonesCount || Input || The number of cyclones in the bank. This allows the user to emulate a bank of cyclones in a single unit.<br>For the 'User Defined Curves' and 'User d50' methods, the number of cyclones is only used to calculate the flow per cyclone.<br>This field is not visible if the user has chosen Method = 'Simple'.
|-
| colspan="3" font style="background: #ebebeb" | The parameters in the access window change depending on the cyclone model chosen by the user. The input parameters for each model will be detailed separately below. Where a model has output parameters that are only displayed for that particular model, these are also shown individually. The Results fields that are common to all methods are shown in the [[#Common Results|Common Results]] section.
|-
| colspan="3" font style="background: #ebebeb" |

==== Simple (no PSD) ====
|-
| rowspan="2" valign="top" | UFSolidsMethod || UF Solids Fraction || The user may set the required fraction of solids in the cyclone underflow.
|-
| UF Solids Conc25 || The user may set the required concentration of solids in the cyclone underflow at 25°C.
|-
| UFSolidFracReqd || Input || Only visible if the ''UF Solids Fraction'' method has been chosen. The required mass fraction of solids in the cyclone Underflow stream.
|-
| UFSolidConc25Reqd || Input || Only visible if the ''UF Solids Conc25'' method has been chosen. The required concentration of solids in the cyclone Underflow stream at 25°C.
|-
| rowspan="4" valign="top" | RecoveryMethod || Liquid Recovery R_f ||
|-
| Slurry Recovery R_v || The user may set the required volume recovery of slurry from the Feed stream to the cyclone underflow.
|-
| Solids Mass Recovery || The user may set the required mass recovery of solids from the Feed stream to the cyclone underflow.
|-
| Solids Volume Recovery || The user may set the required volume recovery of solids from the Feed stream to the cyclone underflow.
|-
| LiquidRecoveryReqd / RfReqd || Input || Only visible if the ''Liquid Recovery R_f'' method has been chosen. The required mass fraction of the Feed liquids that must report to the cyclone Underflow stream.
|-
| SlurryRecovery / dRv || Input || Only visible if the ''Slurry Recovery R_v'' method has been chosen. The required mass fraction of the Feed slurry that must report to the cyclone Underflow stream.
|-
| SolidsMassRecovery / dRsm || Input || Only visible if the ''Solids Mass Recovery'' method has been chosen. The required mass fraction of the Feed solids that must report to the cyclone Underflow stream.
|-
| SolidsVolRecovery / dRs || Input || Only visible if the ''Solids Volume Recovery'' method has been chosen. The required volume fraction of the Feed solids that must report to the cyclone Underflow stream.
|-
| font style="background: #ebebeb" colspan="3" | ''Results''
|-
| UF.SolidFrac / UF.Sf || font style="background: #ebebeb" | Display || The mass fraction of solids in the cyclone Underflow stream.
|-
| UF.SolidConc25 || font style="background: #ebebeb" | Display || The concentration of solids in the cyclone Underflow stream at 25°C.
|-
| colspan="3" | Please see [[#Common Input Fields|Common Input Fields]] for a description of the ''Selected Solid Species Calculation Method'' inputs.
|-
| colspan="3" font style="background: #ebebeb" | '''''Specification'''''
|-
| colspan="3" font style="background: #ebebeb" |

==== User Defined Curves ====
|-
| colspan="3" |
# The user will also see a tab [[#Partition Curve Page|'PartCrv']] where they must enter the fraction of each size interval reporting to the cyclone underflow. An example of an Efficiency Curve is shown in [[#Efficiency Curves|Efficiency Curve Theory]].
# Please see [[#Common Input Fields|Common Input Fields]] for a description of the ''Underflow Requirements'' and ''Selected Solid Species Calculation Method'' inputs.
|-
| colspan="3" font style="background: #ebebeb" |

==== User d50 ====
|-
| CutSizeReqd / d50Reqd || Input || The required d<sub>50</sub> of the cyclone.
|-
| colspan="3" | Please see [[#Common Input Fields|Common Input Fields]] for a description of the ''Underflow Requirements'', ''Efficiency Curve'' and ''Selected Solid Species Calculation Method'' inputs.
|-
| colspan="3" font style="background: #ebebeb" |

==== Krebs Cyclone ====
|-
| colspan="3" font style="background: #ebebeb" | ''(The feed solids volume concentration must be greater than 53% to use this method.)''
|-
| CycloneDiameter / Dc || Input || The diameter of the cyclone.
|-
| Kr.Factor || Input || This is the correction factor to account for differences in the cyclone geometry from the 'optimum' dimensions. This is used to adjust the calculated cut point of the cyclone. The default value is 1. (See [[#Krebs Model|Equation (1) in the Krebs theory]])
|-
| PressChange / dP || font style="background: #ebebeb" | Display || The calculated pressure drop across the cyclone.
|-
| colspan="3" | Please see [[#Common Input Fields|Common Input Fields]] for a description of the ''Underflow Requirements'', ''Efficiency Curve'' and ''Selected Solid Species Calculation Method'' inputs.
|-
| colspan="3" font style="background: #ebebeb" |

==== Plitt Cyclone ====
|-
| colspan="3" font style="background: #ebebeb" | ''Cyclone Geometry''
|-
| CycloneDiameter / Dc || Input || The diameter of the cyclone.
|-
| InletDiameter / Di || Input || The inside diameter of the cyclone feed inlet.
|-
| VortexDiameter / Do || Input || The inside diameter of the overflow or the vortex finder.
|-
| SpigotDiameter / Du || Input || The inside diameter of the underflow or the spigot diameter.
|-
| Height / h || Input || The free vortex height of the cyclone, defined as the distance from the bottom of the vortex finder to the top of the underflow orifice.
h = Total length of the cyclone - vortex length
|-
| colspan="3" font style="background: #ebebeb" | ''Correction Factors''
|-
| d50Factor || Input || This Factor is used to adjust the d<sub>50</sub> of the cyclone. Increasing this value will increase the d<sub>50</sub> used in the calculations, and hence increase the amount of solids reporting to the cyclone Overflow. Please see [[Cyclone#Plitt Model|Equation (7) in the Plitt Model Theory]].
|-
| SharpFactor || Input || Sharpness Factor is used to adjust "m". Increasing this value will increase the sharpness of separation and more of the coarse particles will report to the underflow. Please see [[Cyclone#Plitt Model|Equation (11) in the Plitt Model Theory]].
|-
| PressFactor || Input || Press Factor is used to adjust "dP". Increasing this value will increase the pressure drop across the cyclone and hence change the size recovery of the cyclone. Please see [[Cyclone#Plitt Model|Equation (8) in the Plitt Model Theory]].
|-
| SFactor || Input || SFactor is used to adjust "S", which influences the recovery of feed volume to the cyclone underflow. Increasing this value will increase the recovery to the cyclone underflow. Please see [[Cyclone#Plitt Model|Equation (10) in the Plitt Model Theory]].
|-
| OldSharpnessCalc || Tickbox || Only available in Build 138.27040 or later. If ticked, the original (incorrect) calculation for sharpness will be used. If unticked (recommended), the correct calculation will be used for the sharpness calculation.
|-
| OverrideSharpness || Tickbox || If ticked, this will enable the user to override the calculated Sharpness parameter. (in earlier builds (before 138.27040) this parameter is shown further down the page).
|-
| colspan="3" font style="background: #ebebeb" | Please see [[#Common Input Fields|Common Input Fields]] for a description of the ''Efficiency Curve'' and ''Selected Solid Species Calculation Method'' inputs.
|-
| font style="background: #ebebeb" colspan="3" | ''Results''
|-
| CutSize / d50 || font style="background: #ebebeb" | Display || The calculated d<sub>50</sub> of the cyclone.
|-
| PressChange / dP || font style="background: #ebebeb" | Display || The calculated pressure drop across the cyclone.
|-
| FeedSolidsVolFrac / Cv || font style="background: #ebebeb" | Display || The calculated solids fraction in the feed by volume.
|-
| VolFlowSplit / S || font style="background: #ebebeb" | Display || The calculated ratio of the underflow volumetric flow to the overflow volumetric flow. Please see [[Cyclone#Plitt Model|Equation (10) in the Plitt Model Theory]].
|-
| VolRecovery / Rv || font style="background: #ebebeb" | Display || Recovery of feed volume to the underflow.
|-
| SolidsRecovery / Rs || font style="background: #ebebeb" | Display || Recovery of feed solids to the underflow.
|-
| Bypass / dRf || font style="background: #ebebeb" | Display ||
|-
| RRSharpness / m || font style="background: #ebebeb" | Display || The calculated efficiency exponent in Rosin-Rammler efficiency curve. This is a measure of the sharpness of separation of the cyclone.
|-
| LynchSharpness / alpha || font style="background: #ebebeb" | Display || The calculated alpha term for the Lynch sharpness equation.
|-
| colspan="3" font style="background: #ebebeb" |

==== Nageswararao ====
|-
| rowspan="2" valign="top" | HinderingCalc || Nageswararao || The Nageswararao Hindered Settling Factor will be used. Please refer to [[#Nageswararao_Model|Nageswararao Model Theory]] for more information.
|-
| Richardson-Zaki || The Richardson Zaki Settling Factor will be used. Please refer to [[#Nageswararao_Model|Nageswararao Model Theory]] for more information.
|-
| colspan="3" font style="background: #ebebeb" | ''Cyclone Geometry''
|-
| CycloneDiameter / Dc || Input || The diameter of the cyclone.
|-
| InletDiameter / Di || Input || The inside diameter of the cyclone feed inlet.
|-
| VortexDiameter / Do || Input || The inside diameter of the overflow or the vortex finder.
|-
| SpigotDiameter / Du || Input || The inside diameter of the underflow or the spigot diameter.
|-
| CylSectLength / Lc || Input || The length of the ''cylindrical'' section of the cyclone.
|-
| FullConeAngle / theta || Input || The angle of the cyclone cone.
|-
| colspan="3" font style="background: #ebebeb" | ''Material Constants''
|-
| KQ0|| Input ||
|-
| Kd0|| Input || Material dependent constant for performance characteristic, Pi.
|-
| KW0|| Input || Material dependent constant for performance characteristic, Pi.
|-
| KV0|| Input ||
|-
| colspan="3" font style="background: #ebebeb" | Please see [[#Common Input Fields|Common Input Fields]] for a description of the ''Efficiency Curve'' and ''Selected Solid Species Calculation Method'' inputs.
|-
| font style="background: #ebebeb" colspan="3" | ''Dimensionless Results''
|-
| EulerNumber / EU || font style="background: #ebebeb" | Display ||
|-
| EulerFroude / EF || font style="background: #ebebeb" | Display || Product of Euler and Froude numbers.
|-
| HinderedSettling / lambda || font style="background: #ebebeb" | Display || Hindered settling factor, a function of the volumetric fraction of feed solids (FeedSolidsVolFrac/Cv). Used in equation 13, see [[#Nageswararao Model|Nageswararao Model Theory]] for more details.
|-
| font style="background: #ebebeb" colspan="3" | ''Stream Dependent Results''
|-
| FeedSolidsVolFrac / Cv || font style="background: #ebebeb" | Display || The calculated solids fraction in the feed by volume.
|-
| FeedVolFlow / Q || font style="background: #ebebeb" | Display || Feed volume flow per cyclone.
|-
| PressChange / dP || font style="background: #ebebeb" | Display || The calculated pressure drop across the cyclone.
|-
| SlurryDensity / RhoP || font style="background: #ebebeb" | Display || The density of the feed slurry.
|-
| InletVelocity / Vi || font style="background: #ebebeb" | Display || Inlet velocity.
|-
| CycloneVelocity / Vc || font style="background: #ebebeb" | Display || Cyclone velocity.
|-
| font style="background: #ebebeb" colspan="3" | ''Recovery''
|-
| d50 || font style="background: #ebebeb" | Display || The calculated d<sub>50</sub> of the cyclone.
|-
| ActualRecovery / Rf || font style="background: #ebebeb" | Display || Recovery of water to the underflow.
|-
| VolRecovery / Rv || font style="background: #ebebeb" | Display || Recovery of feed volume to the underflow.
|-
| RfW || font style="background: #ebebeb" | Display ||
|-
| RfV || font style="background: #ebebeb" | Display ||
|-
| colspan="3" font style="background: #ebebeb" |

==== Common Input Fields ====
|-
| font style="background: #ebebeb" colspan="3" | The following 3 fields are visible for the 'simple' cyclone methods - ''User Defined Curves'', ''User d50'' and ''Krebs Cyclone'' methods.
|-
| UnderflowConc || Tickbox || If this box is ticked it allows the user to set the solids in the underflow as a concentration at 25°C. Otherwise the user sets the fraction of solids in the underflow.
|-
| UFSolidFracReqd || Input || The user sets percentage of solids in the cyclone underflow. This field is only visible if 'UnderflowConc' is NOT ticked.
|-
| UFSolidConc25Reqd || Input || The required concentration of solids in the cyclone underflow at 25°C. This field is only visible if 'UnderflowConc' is ticked.
|-
| font style="background: #ebebeb" colspan="3" | The following field is visible for the all cyclone methods. (only available in Build 138 or later)
|-
| VapourToUF || Input || The required fraction of vapours in the feed that will pass to the underflow stream. The rest will pass to the overflow stream.
|-
| font style="background: #ebebeb" colspan="3" | The following fields are visible for most of the cyclone methods.
|-
| colspan="3" font style="background: #ebebeb" | ''Efficiency Curve''
|-
| rowspan="4" valign="top" | SplitMethod || Rosin-Ramler || The [[#Rosin-Rammler|Rosin-Rammler method]] is used to calculate the solids split in each size interval.
|-
| Lynch || The [[#Lynch|Lynch method]] is used to calculate the solids split in each size interval.
|-
| Whiten Fishhook || The [[#Whiten Fishhook|Whiten-Fishhook method]] is used to calculate the solids split in each size interval.
|-
| User Curve || The user can define their own partition curve.
|-
| Sharpness / m || Input || Only visible if the ''Rosin-Ramler'' method has been chosen. The required sharpness value. For Plitt model when ''OverrideSharpness'' is not selected then this is calculated by Plitt model.
|-
| SharpnessFactor / Alpha || Input || Only visible if the ''Lynch'' or ''Whiten-Fishhook'' methods have been chosen. The required sharpness factor or Alpha value. For Plitt model when ''OverrideSharpness'' is not selected then this is calculated by Plitt model.
|-
| Fishhook / Beta || Input || Only visible if the ''Whiten-Fishhook'' method has been chosen. The required Beta value used in the Whiten-Fishhook equation.
|-
| Beta* || font style="background: #ebebeb" | Display || Only visible if the ''Whiten-Fishhook'' method has been chosen. The calculated Beta* value used in the Whiten-Fishhook equation.
|-
| colspan="3" font style="background: #ebebeb" | '''SolSp...'''
|-
| colspan="3" font style="background: #ebebeb" | '''''Selected Solid Species Calculation Method'''''
[[File:SolSpeciesCalc1.png]] - Please see [[#Example Solid Species (bypass) calculation|Example Solid Species (bypass) calculation]] for sample calculation.
|-
| ShowSelectedSolids || Tickbox || If ticked, allows user to override calculated solid splits for specific solid species.
|-
| Count || Input || Only visible if ''ShowSelectedSolids'' has been ticked. The number of solid species for which the user wishes to override the calculated solid splits.
|-
| SpeciesX || List || The number of these fields will be equal to ''Count''. The user can choose a specific solid species from the list of all solid species in the project.
|-
| colspan="3" font style="background: #ebebeb" | For each selected species the following parameters are displayed
|-
| WithLiq || Input || The fraction of the selected solid species which will follow the liquid split.
|-
| To UF || Input || The fraction of the selected solid species which will report directly to the underflow.
|-
| To OF || Input || The fraction of the selected solid species which will report directly to the overflow.
|-
| WithSol || font style="background: #ebebeb" | Display || The fraction of the selected solid species which will follow the solid split. <br> If using multiple solid species with size definition, please see notes under [[#Example Solid Species (bypass) calculation|Example Solid Species (bypass) calculation]] for more information.
|-
| colspan="3" font style="background: #ebebeb" |

==== Common Data Fields ====
|-
| font style="background: #ebebeb" colspan="3" | ''Actual Results''
|-
| font style="background: #ebebeb" colspan="3" | The following field is visible for the ''User d50'' and ''Krebs Cyclone'' method.
|-
| CutSize / d50 || font style="background: #ebebeb" | Display || The calculated d<sub>50</sub> of the cyclone.
|-
| font style="background: #ebebeb" colspan="3" | The following 5 fields are visible for the ''User Defined Curves'', ''User d50'' and ''Krebs Cyclone'' methods.
|-
| UF.SolidFrac / UF.Sf || font style="background: #ebebeb" | Display || The fraction of solids in the cyclone underflow stream.
|-
| UF.SolidConc25 || font style="background: #ebebeb" | Display || The solids concentration at 25°C in the cyclone underflow stream.
|-
| FeedSolidsVolFrac / Cv || font style="background: #ebebeb" | Display || The calculated solids fraction in the feed by volume.
|-
| LiquidRecovery / Rf || font style="background: #ebebeb" | Display || The fraction of liquids in the feed reporting to the underflow stream.
|-
| SlurryRecovery / Rv || font style="background: #ebebeb" | Display || The volume fraction of slurry in the feed reporting to the underflow stream.
|-
| SolidsRecovery / Rs || font style="background: #ebebeb" | Display || The fraction of solids in the feed reporting to the underflow stream.
|-
| font style="background: #ebebeb" colspan="3" | The following 4 fields are visible for the ''Simple (no PSD)'' and ''Plitt'' methods.
|-
| font style="background: #ebebeb" colspan="3" | ''Recoveries''
|-
| ActualVolumeRecovery / ActRv || font style="background: #ebebeb" | Display || The volume fraction of slurry in the feed reporting to the underflow stream.
|-
| ActualLiquidRecovery / ActRf || font style="background: #ebebeb" | Display || The fraction of liquids in the feed reporting to the underflow stream.
|-
| ActualSolidsRecovery / ActRs || font style="background: #ebebeb" | Display || The fraction of solids in the feed reporting to the underflow stream.
|-
| ActualSolidMassRecovery / ActRsm || font style="background: #ebebeb" | Display || The mass fraction of solids in the feed reporting to the underflow stream.
|}

=== Partition Curve Page ===

The Hydrocyclone has a section showing the partition curve. This page is displayed if the ''User Defined Curves'', ''User d50'', ''Krebs Cyclone'' or ''Nageswararao'' methods are chosen.

The model will calculate the partition curve for the Hydrocyclone configuration and display it on this page.

{| border="1" cellpadding="5" cellspacing="0"
|-
| Width=200|'''Tag (Long/Short)''' || Width=100|'''Input or Calc''' || Width=1000|'''Description'''
|-
| font style="background: #ebebeb" colspan="3" | ''Efficiency Curve''
|-
| CorrectedCurve || Tickbox || Only visible if the ''User Defined Curves'' method or ''User Curve'' SplitMethod has been chosen. If ticked, allows to user to set the Corrected Partition Curve, which is applied directly to the solids separation. If not ticked, the user enters the Actual Partition Curve which is "corrected" prior to being applied to the solids separation.
|-
| font style="background: #ebebeb" colspan="3" | For each size interval, the following fields are shown.
|-
| Corrected || Input/Display || This will be an input field if the ''User Defined Curves'' method or ''User Curve'' SplitMethod has been chosen and the ''CorrectedCurve'' box has been ticked. The partition curve applied to the solids separation.
|-
| Actual || Input/Display || This will be an input field if the ''User Defined Curves'' method or ''User Curve'' SplitMethod has been chosen and the ''CorrectedCurve'' box has NOT been ticked. The desired partition curve prior to "correction".
|}

=== Example Solid Species (bypass) calculation ===

Below is an example from the '''[[Example_-_04SizeDistribution_Projects#Milling_and_Magnetic_Separation_Project|Milling and Magnetic Separation Example]]''', looking at the behaviour of '''Prim_Mill_Cyc'''.

*In this example, the feed to the cyclone contain 3 species (Fe2O3, Fe3O4 and SiO2) with size distribution data defined (caused by different recovery values from the Rough_Mag_Sep).
*We will look at how the solids recovery is affected when we select one species to split differently using the SolSp section.
*Five sample calculations were completed, note that the feed to the cyclone is not constant as underflow is being recirculated back to the cyclone feed.
*An example species selection and species split setting is given below, this matches Case 2 in the table given below:
*:[[File:SolSpeciesCalc1.png]]

*Sample Data Setting and Calculated Results.
*:[[File:SolSpeciesCalc2.png]]

NOTES:
#Solid Species Split are calculated as follows:
#*If a solid species has its own size distribution defined, then the solid species will split based on its size data.
#*If solid species have no individual size distribution data defined (let's call these solids the ''remaining solids''), then the ''remaining solids'' will follow the same split as the species with size distribution defined.
#*If multiple species have size distribution defined, then the ''remaining solids'' will follow the same split as LAST species with size distribution defined. In our example, this species is SiO2.
#If a solid species is selected using the "SolSp" Option, then this will override its defined size distribution data, if any, and follow the split method defined in the SolSp section.
#*Case 1: Fe3O4 ignores its size distribution definition, and follows the size distribution as per ''remaining solids''. (With Sol = follow SiO2 Split)
#*Case 2: Fe3O4 ignores its size distribution definition, and splits 65% to U/F and 35% to O/F.
#*Case 3: Fe3O4 ignores its size distribution definition, and splits 65% straight to U/F, the other 35% follows the same split as ''remaining solids''. So the total species split to underflow is 65% + 35% * SiO2 Split = 65 + 35 * 0.51 = 83%.
#*Case 4: Fe3O4 ignores its size distribution definition, and follows the split as per liquid split.

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=Separation | DllSubGroup=Size Separation | UnitOp=Hydrocyclone | Group=Size Distribution }}

Sugar Fugal 2

2023-02-22T23:55:50Z

John.McFeaters: /* Warnings */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.

|-
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.

|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T23:54:52Z

John.McFeaters: /* Stage Impurities */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.

|-
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.

|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T23:54:02Z

John.McFeaters: /* Data Access Page */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.

|-
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T23:50:40Z

John.McFeaters: /* Data Access Page */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-
==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T23:04:25Z

John.McFeaters: /* Data Access Page */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-
==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T23:02:54Z

John.McFeaters: /* Vent Mass Flow */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-

==== Vent Mass Flow ====

|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
|

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T23:02:17Z

John.McFeaters: /* Data Access Page */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-

==== Vent Mass Flow ====

|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:59:54Z

John.McFeaters: /* Data Access Page */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-
==== Vent Mass Flow ====

|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:59:01Z

John.McFeaters: /* Outlet Connection Molasses Brix */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-
==== Vent Mass Flow ====

|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:58:38Z

John.McFeaters: /* Vent Mass Flow */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-
=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:58:13Z

John.McFeaters: /* Vent Mass Flow */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-
==== Vent Mass Flow ====

|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:57:25Z

John.McFeaters: /* Outlet Connection Molasses Brix */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-
==== Vent Mass Flow ====

|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:56:41Z

John.McFeaters: /* Vent Mass Flow */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:56:18Z

John.McFeaters: /* Vent Mass Flow */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-

==== Vent Mass Flow ====

|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:55:31Z

John.McFeaters: /* Vent Mass Flow */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-

==== Vent Mass Flow ====

|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:55:19Z

John.McFeaters: /* Outlet Connection Molasses Brix */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-

==== Vent Mass Flow ====

|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

==== Vent Mass Flow ====

|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:54:18Z

John.McFeaters: /* Vent Mass Flow */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-
==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

==== Vent Mass Flow ====

|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:53:29Z

John.McFeaters: /* Outlet Connection Molasses Brix */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-
==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:52:42Z

John.McFeaters: /* Vent Mass Flow */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:51:43Z

John.McFeaters: /* Data Access Page */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:50:34Z

John.McFeaters: /* Outlet Connection Molasses Brix */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:49:27Z

John.McFeaters: /* Mass Flows Page */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |
|-
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:47:45Z

John.McFeaters: /* Stage Impurities */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
|-
|FeedImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Feed.
|-
|PurgeImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Purge Stream.
|-
|Wash01MolImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Washings.
|-
|BsktWashingsImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Basket Washings.
|-
|ProductImp||font style="background: #ebebeb"| Display || Mass Flow Rate of Impurities in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:45:48Z

John.McFeaters: /* Stage Sucrose */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|FeedSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Feed.
|-
|PurgeSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Purge Stream.
|-
|Wash01MolSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Washings.
|-
|BsktWashingsSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Basket Washings.
|-
|ProductSucrose||font style="background: #ebebeb"| Display || Mass Flow Rate of Sucrose in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:43:50Z

John.McFeaters: /* Stage Solids */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Feed.
|-
|PurgeSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Purge Stream.
|-
|Wash01MolSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Washings.
|-
|BsktWashingsSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Basket Washings.
|-
|ProductSolids||font style="background: #ebebeb"| Display || Mass Flow Rate of Solids in Product Cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Sucrose ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:39:16Z

John.McFeaters: /* Data Access Page */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|}

=== Mass Flows Page ===

'''Class: MassFlows''' - The third tab page in the access window will have this name. Results data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Solids ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Stage Sucrose ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Impurities ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}

Sugar Fugal 2

2023-02-22T22:36:12Z

John.McFeaters: /* Warnings */

[[Category:Models]] [[Category:Sugar]]
{{Navigation|[[Models]]|[[Models#Sugar Models|Sugar Models]]}}

{{Sugar Models Header Tabs|currentpage=7}}
----
{{TOC}}
== General Description ==

The Sugar Fugal2 unit operation is available with the Sugar add-on.

The Sugar Fugal2 is a type of centrifuge used to separate and wash molasses from sugar crystals. Massecuite is loaded into a porous walled basket in the fugal which is then spun at high speeds. The sugar crystals are retained in the basket and centrifugal force pulls the molasses out of the sugar crystals and through the basket walls where it is collected and removed. Water sprays may be used to wash further molasses from the sugar crystals during the process. Some sugar crystal may be dissolved by the wash water during this stage of the operation. The sugar is then ''plowed out'' of (removed from) the basket leaving a small fraction of the sugar on the walls. A basket wash spray is used to dissolve this remaining sugar and the the cycle is then repeated. The purged molasses, washings and basket washings may be collected into a single stream leaving the fugal or they may be split into a high and low purity stream leaving the fugal.

In reality a Sugar Fugal2 is a batch device. However, the cycle times are generally short (typically about 200 seconds) so the fugal may be approximated as a continuous operation for steady state modeling purposes.

The incoming feed to the fugal is a slurry of sugar crystals and mother molasses. The sugar crystal is assumed to be pure sucrose and all of the impurities are assumed to be in the molasses. The molasses is an aqueous mixture of water, sucrose and impurities. As molasses is removed from the cake, the massecuite purity of the cake increases. The purity of the cake is a measure of how much of the mother molasses has been removed from the cake. The purity of the molasses may also increase if sugar crystal is dissolved during the wash stage.

The Sugar Fugal2 process is described by the following steps;

'''Purge''' Molasses is removed by centrifugal force in the purge step. In this stage only molasses is removed and all crystal is assumed to remain in the basket along with some fraction of the mother molasses. The massecuite purity of the cake remaining in the basket (sugar crystals and retained molasses) rises as impurities are removed with the molasses. The amount of molasses retained with the cake determines the massecuite purity (NB the measure of cake purity is always the massecuite purity).

'''Wash''' An ''Optional'' Wash Stage is used to remove more of the impurities. In this stage wash water is sprayed onto the cake. Some of the molasses is removed by centrifugal force and some of the molasses is removed through displacement by the wash water. Some of the wash water may bypass through the cake with little interaction, some of the wash water may be retained in the cake and some of the wash wash water may dissolve some sugar crystals in the cake as it passes through.

The fraction of the impurities remaining in the cake are determined by specifying either (1) the cake purity rise or (2) the target cake purity.

The extent of dissolution of sugar crystals is determined by specifying either (1) the purity rise in the molasses or (2) the dry substance loss ratio. The dry substance loss is the ratio of dry substance in the fugal feed lost to the washings per mass of wash water. The solids loss includes some of the impurities and sucrose from the mother molasses and potentially some dissolved crystal.

The amount of water in remaining in the cake is specified as the moisture content which is the mass fraction of water in the cake after the wash stage.

When no wash is connected, there is no wash action and this step is skipped.

'''Basket Wash''' A user specified fraction of the feed sucrose ''crystal mass'' is assumed to remain in the basket after plow out. A fraction of the washed crystal and cake molasses mixture from the wash stage is retained in the basket to give the required crystal mass. The rest of the washed crystal/molasses mixture leaves the unit as product sugar. Basket wash water is sprayed onto the basket to dissolve the remaining sugar and the wash water sugar solution leaves as basket washings. The solubility of sucrose in the wash water is calculated. Generally the extent of dissolution should be 100% and all sucrose dissolved. However, if there is insufficient wash water or if the wash water is too cold, sugar will only dissolve to the limit of solubility. If this happens the basket washings will contain some sucrose crystal and a warning will be displayed.

'''Sugar Outlet Connection''' A sugar crystal product stream is always required for the washed sugar crystals.

'''Molasses Outlet Connections''' There are two outlet connection configurations for the molasses and washings from the fugal. The molasses, washings and basket wash streams may be sent out as a single combined stream of molasses or they may be split between a low purity and a high purity molasses outlet stream (for example purge molasses goes to a low purity outlet stream and washings and basket washings to a high purity outlet stream). In the model, a low purity connection is always required and the high purity stream is optional.

'''Molasses Split''' When there are two molasses outlet connections, the fraction of each stream (purge, washings and basket wash) to each connection may be specified. This option allows control over the sharpness of the cut between the outlet streams. This accounts for the fact that there is always some material retained in the trough and some mixing between the streams from the various stages of the process. In the model this is specified by the ''separation efficiency''. For example, if the separation efficiency for the purge stream is 90%, then 90% of the purge flow will go to the low purity outlet connection and 10% will go to the high purity outlet connection.

'''Vapors''' Any vapours in the input streams are sent to the vent stream - a warning is displayed if there are vapours in any of the input streams or if there is evaporation and there is no vent connected.

'''Pressure''' The exit pressure of all streams is atmospheric pressure (NB the atmospheric pressure that is specified in the project - see [[Plant_Model#Environment_Tab]]).

'''Heat Loss''' The Sugar Fugal2 model includes optional heat loss to the environment. There are two different heat loss models available. The wash water is typically hotter than the massecuite and is sprayed onto the sugar. The environmental heat loss is taken from the wash water before it mixes with the massecuite. The total heat loss is calculated and then taken proportionally from the wash water streams based on their relative mass flows.

'''Evaporation''' The Sugar Fugal2 also includes the option to specify an evaporation rate from the wash water. The overall evaporation rate is taken from the individual wash water streams in proportion to relative mass flow. Heat loss and evaporation are included in the energy balance.

'''Energy''' The Fugal2 model conserves energy and calculates temperatures after the wash stage and after the basket wash. It is assumed that the cake and the washings are at the same temperature after wash and that the cake and basket washings are at the same temperature after the basket wash. The model allows for evaporation and environmental heat loss which are removed in proportion to mass from the wash and basket wash streams. An energy balance is solved simultaneously for the temperature at each stage taking into account the incoming temperatures of the sugar and wash streams, evaporation, heat loss to the environment and the enthalpy of dissolution for any dissolving sucrose.

== Input and Output Connections ==

A number of the inputs and outputs for the sugar fugal are optional. You connect the ones that you want to use depending on how you want the unit to operate. NB it is possible to have some of the output connections in place and direct the flows elsewhere so that they are effectively unused.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Label''' || '''Required / Optional''' || '''Input /Output ''' || colspan="2" | '''Number of Connections''' || '''Description'''
|-
|   ||   ||   || '''Min''' || '''Max. ''' ||  
|-
| FugalFeed|| Required || In || 1 || 5 || Massecuite Feed to the Fugal.
|-
| WashWater1|| Optional || In || 0 || 5 || Wash Water for Wash Stage.
|-
| BasketWash|| Optional || In || 0 || 5 || Wash Water for Basket Wash Stage.
|-
| LowPurityMol || Required || Out || 1 || 1 || Lower Purity Molasses from Fugal.
|-
| HiPurityMol|| Optional || Out || 0 || 1 || Higher Purity Molasses from the Fugal.
|-
| Sugar|| Required || Out || 1 || 1 || Purged and Washed Sucrose Crystal.
|-
| Vent || Optional || Out || 0 || 1 || Vent outlet containing all Vapors - NB required if there are vapors present.
|-
|}

== Behavior when Model is OFF ==

The sugar fugal may be turned ''Off'' by deselecting the ''On'' tick box in the access window. When the unit is off the following behavior occurs:
* If the unit has a valid feed stream (some mass flow and sucrose crystals present), then all material will flow through to the Product Sugar Stream with no changes or heat exchange.
* If the feed stream is not valid (no mass flow or no sugar crystals), then all material will flow through to the Low Purity (Purge) Molasses stream with no changes or heat exchange.

NB any gases in either feed or wash water streams will remain with those streams when the unit is off.

== Model Theory ==

The purge, wash, plow out and basket wash stages occur in sequence.

The feed massecuite to the fugal is a mixture of pure sucrose crystal plus mother molasses. Mother molasses is a mixture of aqueous sucrose, impurities and water. The impurities include all solutes that are not sucrose.

During the ''purge'' step molasses is removed from the feed massecuite until the massecuite remaining in the basket reaches a target purity. The molasses removed during purge is assumed to be the same composition as the mother molasses. There is no crystal lost from the bed in this step.

In the ''wash'' step the wash water is assumed to be pure water. In this step some molasses is removed, some sugar crystal may be dissolved by wash water and removed with the washings and some wash water may be retained in the crystal bed. The set points which determine the dissolution of crystal and the split of aqueous sucrose, impurities and water are;
* The final massecuite purity target - this is specified either directly or by a purity rise from the purge step.
* Either the feed solids mass loss to washings or the purity rise in the molasses to washings.
* The moisture content of the cake remaining in the basket.

A set of algebraic equations for the above relations plus conservation of sucrose can be solved to determine the amount of dissolution and the final component masses in the cake and molasses. The temperature of the cake and molasses are assumed to be the same at the end of the wash stage and is calculated from conservation of energy.

After the wash step the cake is ''plowed out'' and sent the the final sugar stream. A small fraction of the cake remains in the basket and is washed out separately. The cake solids (crystal, sucrose and impurities) remaining in the basket are specified as a percentage of the feed crystal mass.

During the ''basket wash'' water is sprayed into the basket and the crystal in the remaining cake is (or should be) dissolved by the wash water. The saturation coefficient for the basket washings is calculated and the dissolution of crystal in the basket is limited to saturation in basket washings. If there is not adequate capacity to dissolve all of the crystal (insufficient water or temperature) then the undissolved crystal will go out with the washings and a warning will be displayed.

When there is environmental heat loss, the heat loss is removed from the wash water streams before they go into the basket. The heat loss is divided between the streams in proportion to their relative mass flows. Similarly with evaporation, the specified amount of evaporation is divided proportionally between the two wash streams before the wash water enters the basket. Heat loss and evaporation are included in the energy balance.

== Data Sections ==

===SugarFugal===
'''Unit Type: SugarFugal''' - The first tab page in the access window will have this name. User inputs and results are displayed on this page.

In general, the control inputs are defined in terms of parameters that are normally measured in sugar factories.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag (Long/Short)'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" |'''[[Common Data Sections#Common Data on First Tab Page|Common Data on First Tab Page]]'''
|-
| colspan="3" font style="background: #ebebeb" |
====Requirements====
|-
| On || Tickbox || Tickbox used to turn the unit ON or OFF (off behavior is described above).
|-
| TrackStatus|| Tickbox || Option to display warnings.
|-
| font style="background: #ebebeb" colspan="3" |
====Environmental Heat Loss====
|-
| valign="top" rowspan="3" | Method || None || No heat exchange with the environment.
|-
| FixedLoss|| User specified heat loss rate.
|-
| Ambient|| Heat loss determined as a constant times temperature difference from ambient. Qloss = ThermalLossAmbient * (Tprod - Tamb)
|-
| ThermalLossRqd|| Input || The Required Heat Loss Rate - This is only visible if the FixedLoss Method is selected.
|-
| ThermalLossAmbient|| Input || The Heat Loss Rate Constant (kW/K) - This is only visible if the Ambient Method is selected.
|-
| EnvHeatLoss|| font style="background: #ebebeb" | Display || This field displays heat flow to the environment (positive value is heat flow ''from'' Fugal''to'' Environment.).
|-
| font style="background: #ebebeb" colspan="3" |
====Evaporation Loss====
|-
| EvapLossQm|| Input || User specified evaporation rate (set to zero for no evaporation).
|-
| EvapHeatLoss|| font style="background: #ebebeb" | Display || Heat loss due to evaporation (latent heat of vaporization).
|-
| font style="background: #ebebeb" colspan="3" |
====Molasses Outlet Connections====
The following inputs are only visible if both the HighPurity and LowPurity streams are connected.<br>
Set Stage Fractions to High Purity Outlet
|-
|PurgeHPMol|| Input|| Fraction of Purge Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|Wash01HPMol|| Input || Fraction of Wash 1 Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|BsktWashHPMol|| Input || Fraction of Basket Wash Molasses going to high purity outlet connection, balance to low purity molasses connection.
|-
|}

===Purity===
The second tab page in the access window. Input Parameters, results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>|
|-
| font style="background: #ebebeb" colspan="3" |
====Purge====
|-
| valign="top" rowspan="2" | CakePurityControl|| Mass Purity Rise || User specified massecuite purity rise.
|-
| Target Mass Purity|| User specified massecuite purity target.
|-
|FeedMassPurity ||font style="background: #ebebeb"| Display || Massecuite purity of the feed stream.
|-
|PurgePurityReq||Input||Required purity after purging (this controls the amount of molasses that remains in the sugar).
|-
|PurgeMassPurity||font style="background: #ebebeb"| Display || Actual purity after purge and before wash.
|-
|PurgePurityRiseReq||Input || Required purity rise of the purge molasses stream.
|-
|PurgePurityRise||font style="background: #ebebeb"| Display || Purity rise of the purge molasses stream.

|-
| colspan="3" |  
|-
|FeedMolPurity ||font style="background: #ebebeb"| Display || Purity of feed molasses (NB molasses not massecuite).
|-
|PurgeMolPurity ||font style="background: #ebebeb"| Display || Purity of purged molasses.
|-
|PurgeMolSSNCoeff ||font style="background: #ebebeb"| Display || Supersaturation coefficient of purged molasses.
|-
| colspan="3" font style="background: #ebebeb" |

====Wash control Options ====
|-
| valign="top" rowspan="2" |WashCakeControl ||Mass Purity Rise || User specified massecuite purity rise.
|-
|Target Mass Purity|| User Specified massecuite purity.
|-
| valign="top" rowspan="2" |MolassesControl ||Mol Purity Rise || User specified molasses purity rise.
|-
|Solids Loss Ratio|| User specified molasses final sucrose supersaturation.
|-
|WashWaterRatio01||font style="background: #ebebeb"| Display || The Mass Ratio of Wash Water to feed massecuite (expressed as percent).
|-
|WashWater01Brix||font style="background: #ebebeb"| Display || Brix of the Wash Water.
|-
|WashWater01Purity||font style="background: #ebebeb"| Display || Purity of the Wash Water.
|-
|Wash01PurityIn||font style="background: #ebebeb"| Display || Massecuite Purity into Wash Stage.
|-
|Wash01PurityRiseReq|| Input || Target Massecuite Purity Out of Wash Stage 1 (must be > Purity in).
|-
|Wash01Purity||font style="background: #ebebeb"| Display || Actual Massecuite Purity out of Wash stage.
|-
|Wash01PurRiseReq||Input || Required Massecuite purity out of Wash stage 1.
|-
|Wash01PurityRise||font style="background: #ebebeb"| Display || Massecuite Purity out of Wash stage.
|-
|Wash01MoistReqd||font style="background: #ebebeb"| Display || Cake moisture required after wash stage.
|-
|Wash01Moist||font style="background: #ebebeb"| Display || Cake moisture after wash stage.
|-
|Wash01SolidsFrac||font style="background: #ebebeb"| Display || Mass percentage of sugar crystal in the basket after Wash.
|-
| colspan="3" |  
|-
|Wash01MolPurity||font style="background: #ebebeb"| Display || Molasses Purity into Wash 1.
|-
|Wash01MolPurRiseReq||Input || Molasses Purity Rise Required through Wash Stage 1.
|-
|Wash01MolPurityRise||font style="background: #ebebeb"| Display || Molasses Purity rise through Wash Stage 1.
|-
|Wash01DStoWWReqd||Input || The required solids loss ratio for Wash Stage 1.
|-
|Wash01DStoWW ||font style="background: #ebebeb"| Display || The calculated solids loss ratio for Wash Stage 1.
|-
|Wash01XtDissolved||font style="background: #ebebeb"| Display || Mass Percentage of Sugar Crystal dissolved in Wash Stage 1.
|-
|Wash01SSN||font style="background: #ebebeb"| Display || Molasses Sucrose Supersaturation out of Wash Stage 1.
|-
| colspan="3" font style="background: #ebebeb" |

==== Product Crystal ====
|-
|PodMolSSN||font style="background: #ebebeb"| Display || Saturation coefficient of molasses in product cake.
|-
| colspan="3" font style="background: #ebebeb" |

==== Basket Wash ====

|-
|BsktWWtoMassRatio||font style="background: #ebebeb"| Display || Mass ratio of Basket Wash Water to Feed Mass (expressed as percent).
|-
|BsktWashWtrBrix||font style="background: #ebebeb"| Display || Basket Wash Water Brix.
|-
|BsktWashWtrPurity||font style="background: #ebebeb"| Display || Basket Wash Water Purity.
|-
|BasketLossFrac|| Input || Mass of Solids remaining in Basket after plow out as percent of Feed Crystal Mass.
|-
|BasketSolidsLoss||font style="background: #ebebeb"| Display || Mass of Solids remaining in Basket after plow out.
|-
|BsktXtDiss||font style="background: #ebebeb"| Display || Mass of sugar dissolved into basket washings NB should be the same as mass of sugar remaining when there is sufficient wash water.
|-
|WashingsXt||font style="background: #ebebeb"| Display || Sugar Crystal remaining in basket washings NB a warning will be displayed if there is any crystal in the basket washings.
|-
|WashingsPurity||font style="background: #ebebeb"| Display || Purity of the basket washings stream.
|-
|WashingsSSN||font style="background: #ebebeb"| Display || Sucrose Supersaturation of basket washings stream.

|-
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|}

=== Data Access Page ===

'''Class: Data''' - The second tab page in the access window will have this name. Results and calculated data are displayed on this page.

{| border="1" cellpadding="5" cellspacing="0"
| <div style="text-align: center;">'''Tag / Symbol'''</div> || <div style="text-align: center;">'''Input / Calc'''</div> || <div style="text-align: center;">'''Description'''</div>
|-
| colspan="3" font style="background: #ebebeb" |
==== Product Crystal ====
|-
|FeedCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Sugar Crystal in Feed.
|-
|ProductCrystal||font style="background: #ebebeb"| Display || Mass Flow Rate of Product Crystal.
|-
|CrystalDissolved||font style="background: #ebebeb"| Display || Mass Fraction of Crystal Dissolved through Fugal.
|-
|ProductPurity||font style="background: #ebebeb"| Display || Product Massecuite Purity.
|-
| colspan="3" font style="background: #ebebeb" |
==== Wash Water Mass Flows ====
|-
|WashWater01|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Wash Stage (before any evaporation).
|-
|BasketWash|| font style="background: #ebebeb" | Display || Mass Flow of Wash Water to Basket Wash (before any evaporation).
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Mass Flows ====
These are the properties of molasses from the different internal process stages - some streams may be combined before exiting the Fugal.
|-
|QmFeedMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Feed.
|-
|QmPurgeMol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Purge Stream.
|-
|QmWash01Mol|| font style="background: #ebebeb" | Display || Mass Flow of Molasses in Washings.
|-
|QmBsktWash|| font style="background: #ebebeb" | Display || Mass Flow of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Purities ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|PurityFeedMol|| font style="background: #ebebeb" | Display || Purity of Feed Molasses.
|-
|PurityPurgeMol|| font style="background: #ebebeb" | Display || Purity of Purge Stream.
|-
|PurityWash01Mol|| font style="background: #ebebeb" | Display || Purity of Washings.
|-
|PurityBsktWashMol|| font style="background: #ebebeb" | Display || Purity of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Stage Molasses Brix ====
These are the properties of molasses from the different stages - some streams may be combined before exiting the Fugal.
|-
|BrixFeedMol|| font style="background: #ebebeb" | Display || Brix of Feed Molasses.
|-
|BrixPurgeMol|| font style="background: #ebebeb" | Display || Brix of Purge Stream.
|-
|BrixWash01Mol|| font style="background: #ebebeb" | Display || Brix of Washings.
|-
|BrixBsktWashMol|| font style="background: #ebebeb" | Display || Brix of Basket Washings.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Flows ====
Only connected streams are displayed.
|-
|QmLPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to Low Purity Molasses Connection.
|-
|QmHPmolasses|| font style="background: #ebebeb" | Display || Mass Flow to High Purity Molasses Connection.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Purities ====
Only connected streams are displayed.
|-
|PurityLPmolasses|| font style="background: #ebebeb" | Display || Purity of Low Purity Molasses.
|-
|PurityHPmolasses|| font style="background: #ebebeb" | Display || Purity of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Outlet Connection Molasses Brix ====
Only connected streams are displayed.
|-
|BrixLPmolasses|| font style="background: #ebebeb" | Display || Brix of Low Purity Molasses.
|-
|BrixHPmolasses|| font style="background: #ebebeb" | Display || Brix of High Purity Molasses.
|-
| colspan="3" font style="background: #ebebeb" |

==== Vent Mass Flow ====
|-
|VentQm || font style="background: #ebebeb" | Display || Mass flow of Gases to Vent connection.
|-
| colspan="3" font style="background: #ebebeb" |
|}

=== Warnings ===

The model will report errors and warnings for the following conditions.

{| border="1" cellpadding="5" cellspacing="0"
|-
| '''Warning Message''' || '''Comments'''
|-
| Vapour in Feed or Wash Streams and NO Vent Connected|| When vapors are present in any input streams or evaporation is occurring a vent stream must be connected.
|-
| No Crystal in FugalFeed - Check Stream Compositions|| There must be sucrose crystal in the fugal feed stream.
|-
| FugalFeed is not a Sugar Species model|| The feed stream must be a sugar stream.
|-
| Purge Purity Target < Feed Purity|| Purge Purity Target must be greater than the Feed Purity.
|-
| Crystal in Basket Washings - insufficient Wash Water|| There is insufficient wash water available in the basket wash stage to dissolve all the sugar crystal remaining in the basket or the water is too cold.
|-
| Purge Target Purity NOT Achieved||Purge purity target not achieved.
|-
| Wash01 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
| Wash02 Target Purity NOT Achieved||The purity target is set lower than the feed to this stage.
|-
|}

== Adding this Model to a Project ==

{{Adding Model to a Project | DllName=SugarUnits | DllSubGroup=Sugar | UnitOp=Sugar Fugal 2 | Group=Sugar }}