Feeder-Cross Page Connector

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Related Links: DSp page, DSz page


General Description

This unit can function in one of three ways:

  1. A source of material:
    • In this case the user usually sets up the Required Flow from the unit, the Temperature and Pressure AND the species composition, on the Define Species - DSp page;
    • The Default species composition in a Feeder is 100% water. Therefore, if the user does NOT change the species composition, the Feeder will deliver water to the project;
  2. A sink for material, or
  3. A cross page connector, in which case it would be connected to another Feeder / Cross Page unit, typically on another flowsheet page.
    • You may navigate to the connected Feeder by double clicking with the left mouse button on the Feeder.
    • In addition, if the Feeder is not connected, but has the Composition Fetch (CF) enabled, then double clicking with the left mouse button on the Feeder will take you to the CF source (often a pipe). This is only available in SysCAD 9.3.
    • The image below shows how to connect Feeders (This shows the Access Window for SysCAD 9.3).

Connections

Feeder Connected Rev 1.png


  1. If two units are connected as cross page connectors, as shown in the left hand image above:
    • Condensate (operation mode Sink) is connected to Condensate_Return (operation mode Source)
    • All the feeder information defined in Condensate_Return is greyed out and will be ignored.
    • The down stream link from Condensate_Return will contain exactly the same information as the up stream link of Condensate.
    • Any information in the Condensate_Return unit will be maintained and not lost.
  2. If the cross page connection is disabled, as shown in the right hand image above:
    • There is no connection between the Condensate_Return and the Condensate units.
    • The input fields in Condensate_Return are white and the user may insert any value, which will be used by the unit.

Notes:

  1. The model requires either a single inlet or a single outlet, depending upon its intended use.
  2. A Sink has no input fields - the user may not set anything in this unit - it accepts whatever is delivered by the upstream link.
  3. The user may not type any Feed data into a Source until it has been connected to a downstream link.
  4. A Cross Page Connection can only be established between two Feeder/XPG units.

Diagram

Feeder 2.png

The lines show the stream connections.

Inputs and Outputs

Label Required
Optional
Input / Output No of connections Description
Min Connection Max Connection  
Snk Required Input 1 1 OR  
Src Required Output 1 1  

Model Theory

Used as a material source or sink; OR as a connector between two feeders (usualy on separate graphics pages).

Data Sections

The feeder access window may consist of a number of sections. This number may increase or decrease, based on user configuration and / or number of species. Some of these variables are only relevant in the case of a source. When the unit is connected to another cross page connector, the input variables are not used.

  1. Feed_XPG-1 - this is the first Tab. The user accesses this tab to configure the basic manner in which the Feeder works, or to connect to a another Feeder.
  2. Batch Feed - this section is available on the first Tab in Dynamic projects. This allows users to set the Feeder to deliver a fixed amount of flow.
  3. Content - In SysCAD 9.3 this tab is only visible if 'ShowContent' is ticked. Contains data on the material from the Feeder and may be spread across one or two Tabs, depending on the project and the selected views. This Tab is not visible if the unit is a Sink.
  4. DSp - this tab allows the user to define the species (Define Species) in the material from the Feeder. This may be spread across one or two Tabs, depending on the number of species in the project. This Tab is not visible if the unit is a Sink.
  5. QFeed - Optional tab that is visible if ShowQFeed is enabled. This and subsequent tab pages, e.g. QFeed.. and Sp, shows the properties of the stream into the unit.
  6. QProd - Optional tab that is visible if ShowQProd is enabled. This and subsequent tab pages, e.g. QProd.. and Sp, shows the properties of the stream out of the unit.
  7. VLE - Optional tab that is visible if Vapour Liquid Equilibrium is enabled on the first tab.
  8. PC - Optional tab that is visible if EB.Solubility.On and/or EB.PhaseChange@T.On is enabled on the first tab.
  9. MU - Optional tab, or tabs if there is more than one Makeup, that is visible if Makeups are enabled.
  10. Info tab - contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
  11. Links tab, contains a summary table for all the input and output streams.
  12. Audit tab - contains summary information required for Mass and Energy balance. See Model Examples for enthalpy calculation Examples.


Feeder-Cross Page Connector

Unit Type: Feed_XPG-1 - The first tab page in the access window will have this name.
Please note that the layout described below is valid for SysCAD 9.3

Tag (Long/Short) Input / Calc / Options Description
Common First Data Section

Flow Requirements

Mode MassFlow (Qm) Default. The user may set the Mass flow from the feeder.
VolumeFlow (Qv) The user may set the Volume flow from the feeder.
NVolumeFlow (NQv) The user may set the Normalised Volume flow from the feeder.
Const Pressure The user may set the Pressure at the feeder. This option is only available in Dynamic Transfer mode.
FlowBasis (See Example in the Hints and comments section) All The flow specified will be the flow of All phases from the Source, i.e. if Flow Required = 10t/h, then a total of 10t/h will flow out of the Source.
Solids The flow specified will be the flow of the Solid phase from the Source, i.e. if Flow Required = 10t/h, then 10t/h of Solids will flow out of the Source. If the user has specified a composition of 90% solids and 10% liquids, then the Total Flow = 10t/h Solids + 1.11t/h Liquids = 11.11t/h.
Liquids The flow specified will be the flow of the Liquid phase from the Source, i.e. if Flow Required = 10t/h, then 10t/h of Liquids will flow out of the Source. If the user has specified a composition of 50% liquids and 50% solids, then the Total Flow = 10t/h Liquids + 10t/h Solids = 20t/h.
Vapour The flow specified will be the flow of the Vapour phase from the Source, i.e. if Flow Required = 10t/h, then 10t/h of Vapours will flow out of the Source. If the user has specified a composition of 20% vapours, 70% liquids and 10% solids, then the Total Flow = 10t/h Vapours, 35t/h Liquids + 5t/h Solids = 50t/h.

The SpModel.Reqd field is only shown if more than one Species Model is available in the project (eg. Standard and Bayer3).

SpModel.Reqd Inherit Upstream configuration will be used.
Standard All the variables are calculated using the Mass Weighted Mean of the species.
Species Model Use an alternative species model, such as 'Bayer3' or 'Potash'.
SpModel.Used Standard The Standard species model is being used.
Species Model An alternative species model is being used.
SpModelType Display This field displays the Species Model type used in the unit.
Demand.On TickBox If this is enabled then the feeder will feed in the required mass as demanded by the connected stream. See Demand.
If this is not enabled, then the feeder adds the amount of material as specified by the user.
Demand.Max Input The maximum flow allowed from the Feeder in Demand mode. This field is only visible if Demand.On is enabled.

Required (Mass or Volume) Flow This field is not available if the user selects Const Pressure in Dynamic Transfer mode.

MassFlowReqd / QmReqd Input Visible with MassFlow (Qm) Mode. The mass flow required from the feeder. Note: This will become the minimum flow allowed if Demand.On is enabled.
VolFlowReqd / QvReqd Input Visible with VolumeFlow (Qv) Mode. The volumetric flow required from the feeder. Note: This is minimum flow allowed if Demand.On is enabled.
NVolFlowReqd / NQvReqd Input Visible with NVolumeFlow (NQv) Mode. The normalised volumetric flow required from the feeder. Note: This is minimum flow allowed if Demand.On is enabled.

Temperature & Pressure Requirements

Note: The VLE options are only valid for components with VLE information. When one of the VLE options is chosen, the VLE tab will be visible. Note that some VLE conditions are inherently unachievable: for example you can never have a saturated vapour if there are nonvolatile liquid components present. See these notes. If you try to set an unachievable condition you will get an error.

VLEquilibrium Off Default. No VLE data is applied. The user can enter values for both P_Reqd and T_Reqd.
Saturated_Vap(T) The Feeder composition will be auto adjusted to saturated VAPOUR conditions at the Temperature in the T_Reqd field.
Saturated_Vap(P) The Feeder composition will be auto adjusted to saturated VAPOUR conditions at the Pressure in the P_Reqd field.
SuperHeat_Vap(dT,P) Only available in Build 137 or later. This allows the Feeder mixture to be at superheated conditions at the Pressure in the P_Reqd field. The temperature will be automatically adjusted to be at the saturated temperature plus SuperHeatReqd.
SuperHeat_Vap(T,P) This allows the Feeder mixture to be at superheated conditions. P_Reqd must be  ≤ P_saturated at the specified Temperature (T_Reqd)(SysCAD will auto adjust the pressure if it is greater than the saturated pressure).
Saturated_Liq(T) The Feeder composition will be auto adjusted to saturated LIQUID conditions at the Temperature in the T_Reqd field.
Saturated_Liq(P) The Feeder composition will be auto adjusted to saturated LIQUID conditions at the Pressure in the P_Reqd field.
Subcooled_Liq(dT,P) Only available in Build 137 or later. This allows the Feeder mixture to be at sub-cooled conditions at the Pressure in the P_Reqd field. The temperature will be automatically adjusted to be at the saturated temperature minus SubCoolingReqd.
Subcooled_Liq(T,P) This allows the Feeder mixture to be at sub-cooled conditions. P_Reqd must be  ≥ P_saturated at the specified Temperature (T_Reqd) (SysCAD will auto adjust the pressure if it is less than the saturated pressure).
Saturated(X,T) The Feeder composition will be auto adjusted to saturated conditions at the Temperature in the T_Reqd field, with a vapour fraction (steam quality if the volatile component is H2O) of X_Reqd.
Saturated(X,P) The Feeder composition will be auto adjusted to saturated conditions at the Pressure in the P_Reqd field, with a vapour fraction (steam quality if the volatile component is H2O) of X_Reqd.
Saturated_Non_Cond(T,P) The vapour fraction of the volatile component (X_Rqd) will be auto adjusted to saturated conditions at the Temperature in the T_Reqd field and Pressure in the P_Reqd field, when non-condensable gases are present.
Relative Humidity The Feeder must contain gases. If the user selects this option, SysCAD will adjust the amount of H2O(g) to give the required relative humidity in the gas stream. SysCAD will adjust the fractions of the gases in the Feeder other than H2O(g) proportionally.
Relative Humidity = Partial Pressure of H2O(g) / Saturation Pressure of H2O(g) at Stream Temperature * 100
Please see the YouTube link for a video presentation on using this functionality.
TemperatureReqd / T_Reqd Input / Calc The required temperature of the material from the feeder. This value is calculated if one of the Saturated at pressure or dT VLE options are chosen.
PressureReqd / P_Reqd Input / Calc The required input pressure. This value is not usually required for steady state mass balances. However, for energy balances, especially in the case of steam/water, it is important that the correct pressure is specified. This value is calculated if one of the Saturated at temperature VLE options is chosen.
StaticHead Input Only visible in Dynamic projects. The static head. This will affect the pressure in the downstream pipe.
SuperHeatReqd Input This field is only visible if the SuperHeat_Vap(dT,P) VLE option is selected (only available in Build 137 or later). This is the degrees of superheat of the stream (T - Saturation temperature).
SubCoolingReqd Input This field is only visible if the SubCooled_Liq(dT,P) VLE option is selected (only available in Build 137 or later). This is the degrees of subcooling of the stream (Saturation temperature - T).
X_Reqd(VapourFrac) Input / Calc This field is only visible if VLEquilibrium is in use. The required vapour fraction (or steam quality if the volatile component is H2O) of the material from the feeder. This value is calculated unless the Saturated(X,T) or Saturated(X,P) VLE option is chosen.

Qualities

Qualities

Cross Page Connection

No connection can be made in a Sink unit - the user MUST connect two cross-page connectors via the Source unit.

ConnectionOn Tick Box This is used to enable the configured cross page connection. This may only be accessed on a Source, it cannot be changed on a Sink unit.
Connection / Conn_To Input / List The required Tag Name of the connecting Sink unit. The drop-down list will contain the tags of all un-connected Sinks in the project. The user may also type in the Tag of the required Sink.
Connected_To Display If ConnectionOn is enabled AND a valid Sink Tag is entered in the Conn_To field, then the connected Sink tag is displayed in this field. (You may find the connected Feeder by double left clicking on this unit.)
If this field is blank, then the Source is NOT connected.
Connected Display Displays the status of the cross page connection - either Yes or '-'.

Composition Fetch

Note: When using Composition Fetch (CF) the options selected (eg under CF.What) should not conflict with other settings in the feeder. For example if the VLE is enabled it would be setting composition, T and/or P therefore CF.What must not try fetch any of these. Or for example, if the Bayer Feed Calculator is configured it will set the composition, therefore CF.What cannot fetch the composition. When there is any form of Composition Fetch conflict, SysCAD will give an error message and the Composition Fetch will be ignored.

CF.When Off No information will be transferred automatically. The user may still manually transfer data from the source by pressing the CF.Fetch button.
OnceOff This mode allows a once off automatic information transfer of information at the next project step (if the project is solving) or when project solve/run is started (if the project is stopped). Once the data has been transferred, it will revert back to the off mode.
Continuous This mode allows continuous automatic information transfer while the project is solving. This is similar to a cross page connector in terms of material flow but the solver will treat the unit operations separately. Therefore, for large projects with difficult to solve recycle streams, this is a great way of breaking up the solver network to improve solve speed.
CF.What Nothing No information will be fetched.
T Temperature information from the CF.Source unit (specified by the user) will be used.
T, P Temperature and Pressure information from the CF.Source unit (specified by the user) will be used.
Comp Component make up information from the CF.Source unit (specified by the user) will be used.
Flow Flowrate information from the CF.Source unit (specified by the user) will be used.
T, Comp Temperature and Component make up information from the CF.Source unit (specified by the user) will be used.
P, Comp Pressure and Component make up information from the CF.Source unit (specified by the user) will be used.
T, P, Comp Temperature, Pressure and Component make up information from the CF.Source unit (specified by the user) will be used.
Comp, Flow Components make up and Flowrate information from the CF.Source unit (specified by the user) will be used.
T, Comp, Flow Temperature, Components make up and Flowrate information from the CF.Source unit (specified by the user) will be used.
T, Flow Temperature and Flowrate information from the CF.Source unit (specified by the user) will be used.
T, P, Flow Temperature, Pressure and Flowrate information from the CF.Source unit (specified by the user) will be used.
P, Comp, Flow Pressure, Component make up and Flowrate information from the CF.Source unit (specified by the user) will be used.
T, P, Comp, Flow Temperature, Pressure, Component make up and Flowrate information from the CF.Source unit (specified by the user) will be used.
CF.Ratio Input This allows the user to set a ratio of the feeder flow to the source flow. So, for example, if the ratio = 1 (default value, and most commonly used setting) then the flow from the feeder will be equal to the flow in the source. If the ratio is set to 2, then the feeder flow will be twice that from the source.
CF.Source Input The default is (Self.flows). This option will work if the following sequence of events has taken place. 1) The feeder is connected to another unit via the cross page connector method; 2) the flowsheet has been solved with the connection on. If the above are true, then the feeder will temporarily carry solved flow information. The user can then elect to copy an image of this data and set them as the feeder information by fetching the self flows data.

If the user wants to get information from other unit operations, then the format is:

[Unit Operation Tag Name].[Tab Page Name]

Examples: XPG_1.QProd, P_1.Qo, X_1.QProd, TNK_1.QFeed

CF.WarnOnZeroSrc TickBox If this is enabled then the user will receive a warning if the flow in the source is zero (or if the surge content is zero in a dynamic project)
CF.WarnOnCoExist TickBox
CF.What.Quality TickBox Different tick boxes will be visible, depending on the options enabled in the project. Possible options include: LockUp, Size data and so on. See Qualities Models for more information.
The project in the example shown below has Size Distribution enabled, and therefore the user may also fetch the size data from the stream in the composition fetch:

Composition Fetch Size Distribution.png

CF.Fetch Button The required information is fetched from the CF.Source unit operation and used to set the current feeder configuration.

EB(Feed Processing)...

Solubility.On Tickbox Allows the user to switch on any predefined solubility curve to adjust the composition of material in the feeder.
PhaseChange@T.On Tickbox Only visible if Phase Change at Temperature has been defined for at least one species in the project. Allows the user to switch on any predefined phase changes at temperature in the feeder.
EvalSequence Display The sequence in which the sub models (which are part of the evaluation blocks) will be calculated. The sequence is determined by the priority selection for the individual sub-models.
Makeups Input The number of makeup blocks required. Extra dropdown options Makeup1, Makeup2, etc will be added to allow these to be switched on and off and prioritised in relation to the other sub-models.
MakeupX List This can be used to switch the Makeup Block (MU) on or off and prioritise it in relation to the other sub-models. If this is 'On' then the associated page, MUX becomes visible and may be configured.
Note: This field is only visible if the entry for 'Makeups' is greater then 0. If there is one makeup then X=1. If there are two makeups, then X=1 and X=2, etc.

Results: Flow Conditions

State Display Displays the state of the unit. Options are: Feeder, Sink, Feeder-Connected, Sink-Connected.
MassFlow / Qm Display The mass flow into or out of the unit.
VolFlow / Qv Display The volume flow into or out of the unit.
NVolFlow / NQv Display The normalised volume flow into or out of the unit.
Temperature / T Display The Temperature of the material flowing into or out of the unit.
Density / Rho Display The density of the material flowing into or out of the unit.
NDensity / NRho Display The normalised density of the material flowing into or out of the unit.
Pressure / P Display The pressure of the unit.

Options

PasteData Button Allows the user to paste data copied from a stream (using the 'CopyToClipboard' button). The stream may be in the current SysCAD project, or another project. Only available in SysCAD 9.3.
See How do I copy Stream data to a Feeder?
ShowContent Tickbox Allows the user to view the Content tab of the Feeder. Only available in SysCAD 9.3.
ShowQFeed Tickbox Allows the user to view the Feed tab of the Feeder. This is the flow from the Feeder unit, either via the Cross Page Connection or as set by the user, but prior to any Makeups.
ShowQProd Tickbox Allows the user to view the Product tab of the Feeder. This is the actual flow from the Feeder unit, including any Makeups.

Batch Feed

This functionality allows the user to allow the Feeder to deliver a discrete batch to the project. This section is only available in Dynamic Transfer mode.

Symbol / Tag Input / Calc Description
BatchMethod None The Batch functionality is not enabled.
Total Mass The Batch functionality is enabled and the required batch size is defined in terms of Mass flow. Further fields will become visible if this option is selected allowing the user to set the required batch mass.
The following fields will be visible if Total Mass is selected as the Batch method.
M.BatchAddition Input The Mass of the required Batch. This amount of material will be delivered by the Feeder at the rate specified in Qm.Capacity or Qv.Capacity.
When this value is set the amount of material will be added to the amount of material already in BatchRemaining (the field below), and then this field will revert to 0.
M.BatchRemaining Calc / Input The Mass of material currently in a Batch, i.e. the amount of material in a Batch that still has to be delivered by the Feeder. Normally this value is initialised at the start of a run and then it is calculated by SysCAD from the amount required in M.BatchAddition and the amount already delivered by the Feeder.
However, the user may set this value and hence override the calculated Batch amount at any stage.
If the users sets this as Undefined (or '*') this is equivalent to any infinite Batch and therefore the flow from the Feeder will not be restricted.
M.BatchTotal Display The Total Mass that has flowed from the Feeder using the Batch addition method.
BatchState None No Batch mode has been set.
Inactive A Batch method has been selected, but the Batch is undefined.
Busy A Batch method has been selected, there is material remaining in the Batch, and hence there is flow from the Feeder due to the Batch.
Stop Flow A Batch method has been selected, there is NO material remaining in the Batch, and hence there is no flow from the Feeder, i.e. The Batch will prevent the Feeder from discharging any material.
BatchUsePreset Tickbox This enables the use Preset for the Batch amount.
M.BatchUsePreset Input The Mass of the Batch when the model is Preset. Refer to Preset for more information.


Hints and Comments

  1. The default for FlowBasis is 'All' (Qm_Mode = 'Total' in SysCAD 9.2). See below for an example of the use of the other FlowBasis options.
  2. The default Mode of the Feeder is MassFlow (Qm). The Const Pressure is only intended for use in dynamic simulations. The valid modes for Steady State are MassFlow (Qm), VolumeFlow (Qv) or NVolumeFlow (NQv)
  3. Depending on the method selected in the VLE list box, the feeder composition may automatically be adjusted. Example if VLE saturated_liq is selected and the user sets the species mass fraction to 100% H2O(g), the unit may change this to 100% H2O(l). Please always double check the component make up when changing VLE methods.
  4. If you are using a Feeder in Demand Mode, the number in the QmReqd, or Qv_Reqd, box will NOT indicate the amount of material flowing from the feeder.
  5. If you have elected to enter Species composition flows on an individual basis on the DSP page, (e.g. using the Mass Flow view), then you will not be allowed to enter flowrates in the QmReqd (Mass flow required) field. This is because the total mass flow will be calculated from the individual Species flows entered. If the total mass flowrate input is necessary, simply switch back to the Mass Fraction view after individual flow data input.
  6. The feeder unit operation can be used to connect flow information between graphics pages. There are two easy ways of connecting flow information:
    • Through the Cross Page Connection. If this is successful, the two unit operations will be connected as though there is a physical connection. Thus, when SysCAD is building the solution, these two unit operations will be included in the same solve network.
    • Through Composition Fetch. In this case, an IMAGE of the flow information from the source unit operation is copied onto the current Feeder/Cross Page unit operation. The user can customise the frequency and amount of information fetched.
      NOTE: When using composition fetch, the unit operations stay separated from each other. Thus, there is no permanent connections being made even when the frequency is set to continuous. Therefore, when SysCAD is building the solution, the two unit operations can belong to two separate solve networks. The user can use this method to break up a recycle stream if the solution is difficult to obtain in a closed loop.
  7. If a project is opened using the Open with alternate Configuration command, Feeders MAY lose their species compositions IF the new configuration file does not contain all of the species in the original configuration.
  8. If Composition Fetch is set to 'Continuous', and depending on the CF.What selection, there may be a conflict with other settings. For example the VLE selection may be configured to set the temperature and you have selected temperature under composition fetch, then there is a conflict. Only one of these conflicting configurations should be configured. When there is a conflict, the CF is ignored.
  9. To set up feeder information when flowsheets are being solved separately using Activate/Deactive flowsheet option: Use the CF Fetch - Self Flows option.


Examples

1. Using Composition Fetch

The diagram below shows a feeder (Leach_Solution) that has been connected to a sink (Leached_Soln). While the connection was still intact, SysCAD was solved, thus the Cross Page Connector carries an image of the flow condition, see Results: Flow Conditions section, the calculated information for Qm, Qv, T etc.

Use Composition Fetch to keep the pre-solved intermediate information as the feeder configuration information, this transfers Qm to QmReqd, T to T_Reqd etc.

If the user sets the frequency of the fetch to Continuous, then whenever values change, the feeder configuration will be updated. Therefore, if the Cross page connection is disabled, (either manually or through the deactivate flowsheet option in Project - ProBal setup), the feeder will always contain the previous solved information.

CompositionFetch.png


2. Using Different Flow Basis Options

The user configures the following species make-up in the feeder:

H2O(l) 40%
H2SO4(aq) 8%
SiO2(s) 30%
CaSO4(s) 20%
H2O(g) 1%
H2SO4(g) 1%


This gives 48% liquids, 50% solids and 2% vapour.

If MassFlowReqd = 10t/h, then each row in the following table shows the flow rate from the feeder for each FlowBasis option (The bold black numbers are the flow rates that are set, the blue numbers are calculated):

FlowBasis Total Flowrate (t/h) Solids Flowrate (t/h) Liquid Flowrate (t/h) Vapour Flowrate (t/h)
All 10 5 4.8 0.2
Solids 20 10 9.6 0.4
Liquid 20.83 10.42 10 0.41
Vapour 500 250 240 10


Adding this Model to a Project

Insert into Configuration file

Sort either by DLL or Group.

  DLL: Basic1.dll Units/Links Process: Feeder/Sink/CrossPage
or Group: General Units/Links Process: Feeder/Sink/CrossPage

See Project Configuration for more information on adding models to the configuration file.


Insert into Project

  Insert Unit Process Feeder/Sink/CrossPage

See Insert Unit for general information on inserting units.