General Separator

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Navigation: Main Page -> Models -> Mass Separation Models

Related Links: Solid-Liquid Separator

Introduction

This model can be used as a general separator, especially for separating solids and liquids using the Solid-Liquid Separator sub-model. In addition, a number of sub-models are available which makes this model very flexible so that it can be used to model many types of separation units.

Diagram

Models-Gen Separator-image001.gif

The diagram shows the default drawing of the General Separator, with all of the streams that have to be connected for the unit to operate.

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

Inputs and Outputs

Label Required
Optional
Input
Output
Number of Connections Description
Min Max.
Feed 1 Required In 1 20 The feed to the separator
Underflow 1 Required Out 1 1 The separator underflow.
Overflow Optional Out 0 1 The separator overflow. If this is NOT connected, all material flows out through the Underflow.
Vent Optional Out 0 1 Vent Stream (Vapour only)

Behaviour when Model is OFF

If the user disables the unit, by un-ticking the On tick box, then the following actions occur:

  • The field MassFracToUF becomes visible and the user may set the fraction of the feed stream that reports to the 'Underflow' outlet. The default is 100%.
  • All streams connected to the unit will flow out of the 'Underflow' outlet, unless the user has changed the above field from 100%. In which case the user defined fraction of the Feed will report to the Overflow stream;
  • No sub-models will occur.

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

Flowchart

Models-Gen Separator-flowchart.gif

Data Sections

Summary of Data Sections

  1. GeneralSeparator tab - Contains general information relating to the unit.
  2. RB - Optional tab, only visible if the Reactions are enabled in the Evaluation Block.
  3. EHX - Optional tab, only visible if the EnvironHX is enabled in the Evaluation Block.
  4. Evap - Optional tab that is visible if Evaporator is enabled.
  5. VLE - Optional tab, only visible if the VLEquilibrium is enabled in the Evaluation Block.
  6. MU - Optional tab, or multiple tabs if more than 1 Makeup is selected. Only visible if one or more Makeups are enabled in the Evaluation Block.
  7. Separ - Contains configuration and results of separating material to the underflow and overflow outlets.
  8. QFeed - Optional tab, only visible if ShowQFeed is enabled. This page shows the properties of the mixed stream as the feed to the separator.
    • This is before any Evaluation Block models are evaluated.
  9. Info tab - Contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
  10. Links tab, contains a summary table for all the input and output streams.
  11. Audit tab - Contains summary information required for Mass and Energy balance. See Model Examples for enthalpy calculation Examples.
  12. Additional fields are shown in Dynamic mode. These are described in the Tank - Dynamic Mode.

General Separator Page

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

Tag (Long/Short) Input/ Calc Description

Common Data on First Tab Page

Requirements

On Tick Box This allows the user to enable or disable the unit. If the unit is disabled, no sub-models or separation will occur.
MassFracToUF_WhenOff / MassFracToUF Input This field is only visible if the On tickbox is NOT ticked. This field allows the user to specify the fraction of the incoming streams that will flow to the underflow when the unit is disabled.

OperatingP

Method AutoDetect If there are any liquids AND no vapours present in the feed, outlet streams will take the highest pressure of the feeds. Else (eg. some vapours present) outlet streams will take the lowest pressure of the feeds.
LowestFeed Outlet streams will take the lowest pressure of the feeds.
HighestFeed Outlet streams will take the highest pressure of the feeds.
Atmospheric Outlet streams will be at Atmospheric Pressure. The atmospheric pressure is calculated by SysCAD based on the user defined elevation (default elevation is at sea level = 101.325 kPa). The elevation can be changed on the Species tab page of the Plant Model.
RequiredP Outlet streams will be at the user specified pressure.
IgnoreLowQm Tick Box This option is only visible if the AutoDetect, LowestFeed or HighestFeed methods are chosen. When calculating the outlet pressure and temperature of the tank, SysCAD will ignore the low flow feed streams should this option be selected. The low flow limit is set in the field below.
LowQmFrac Input This field is only visible if the IgnoreLowQm option is selected. This is the amount any stream contributes to the total flow. For example, if the total feed to the tank is 10 kg/s, and this field is set to 1%. Then any feed streams with less than 0.1 kg/s will be ignored in the pressure calculations.
PressureReqd / P_Reqd Input This field is only visible if the RequiredP method is chosen. This is user specified pressure.
Result Display The actual pressure used for the sum of the feeds which will also be the outlet pressure (unless further model options change the pressure).

EB (Evaluation Block)

EvaluationSequence / EvalSequence Calc 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. If none are selected, the default evaluation sequence is MU,RB,EHX,Evap,VLE.
Makeups Input The number of makeup blocks required. Extra dropdown options Makeup1, Makeup2, etc will be added to allow these to be switched on.
Makeup1 List This can be used to switch on the Makeup Block (MU). If this is 'On' then the associated page, MU1 becomes visible and may be configured.
Note: This field is only visible if the entry for 'Makeups' is greater then 0.
Reactions List This can be used to switch on the Reaction Block (RB). If this is 'On' then the associated page, RB becomes visible and may be configured.
Note: The user does not have to configure a reaction file, even if this block is checked.
EnvironHX List This can be used to switch on the Environmental Heat Exchanger (EHX). If this is 'On' then the associated page, EHX may become visible and may be configured.
Note: The user does not have to configure an environmental heat exchange, even if this block is checked.
Evaporation List This can be used to switch on the Evaporation Block (Evap). If this is 'On' then the associated page, Evap may become visible and may be configured.
Note: The user does not have to configure an evaporator, even if this block is checked.
VLEquilibrium List This can be used to switch on Vapour Liquid Equilibrium (VLE). If this is 'On' then the associated page, VLE becomes visible and may be configured.
Note: This option may automatically adjust the species make-up.

Residence Time

ResTime ...
Calc TickBox Allows user to enter a volume for the general separator, then a residence time is estimated based on the flowrate of the feed.
The following fields will only be visible if the Calc tick box is selected.
Volume Input The operating volume of the unit. This will be used to calculate the apparent residence time in the unit.
MassFlow / Qm Calc The mass flow of the material.
Temperature / T Calc The temperature of the material.
Slurry Calc The residence time of the slurry in the unit.
Total Calc The residence time for the slurry and the vapours in the unit.
 
Options
ShowQFeed Tick Box QFeed and associated tab pages (eg Qm) will become visible, showing the properties of the combined feed stream. See Material Flow Section. This will be prior to any sub-model (eg reactions) actions.

Separ Tab Page

This page allows the user to configure the separation between the underflow and overflow streams. Please refer to Solid-Liquid Separator for more information.

Adding this Model to a Project

Insert into Configuration file

Sort either by DLL or Group.

 

DLL:

Separation.dll

Units/Links

Separation:General Separator

or

Group:

Mass Separation

Units/Links

Separation:General Separator

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


Insert into Project

 

Insert Unit

Separation

General Separator

See Insert Unit for general information on inserting units.