Split Flows (Split)

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Split Material Flow		Split Thermal (Requires SplitFlow = On)
Split Flows (Split)	SplitFlow - General Operation	Split Thermal (SplitT)

Related Links: PGM Examples - PGM Class to Set Species Splits

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General Description

By enabling the SplitFlows sub-model, within a unit, the user has control over the split to the outgoing streams. If this sub-model is NOT enabled, then the unit will split the material from the unit equally between the outgoing streams.

• To enable the Split Flows, the user must tick the SplitFlows tickbox on the first tab page of the unit;
• The Split tab is then available for configuration.
• The user may configure the split between the outgoing flows.
• The streams may then be split purely on a mass percentage basis, or the phase split may be specified, or user defined species may be controlled in certain streams.
• This sub-model is commonly used in the Tie and Tank in Steady State models to control the flows from these units.

Video Links

There are a number of videos describing the various operational methods available in the SplitFlows sub-model - these links are shown in the table below. This link describes how to enable the SplitFlows Model and set pipe priorities: YouTube link.

Data Sections

The first variable that can be configured on the access page for the "General Split Flows Model" is "Operation". Depending on the option chosen by the user, the access page will change. Each option and its associated access page are described in the sections below.

General	Mass Fraction	Mass Flow	Volume Fraction	Volume Flow	Phase Mass Fraction	Phase Mass Flow	Phase Volume Flow	Species Mass Fraction	Species Mass Flow	Demand Mass Flow	Phase Recovery	Solids Recovery	Water Recovery	Gas Vent	Target Stream

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The Split tab page can be used to specify how flow is distributed down stream.

Tag (Long/Short)	Input/ Outputs	Description
GM ...
General Split Flows Model
Operation	General	Configure outgoing streams using mixture of methods.
	Mass Frac	Split by mass fraction.
	Mass Flow	Specify mass flows.
	Volume Frac	Split by volume fraction.
	Volume Flow	Specify volume flows.
	Phase Mass Frac	Split each phase by mass fraction.
	Phase Mass Flow	Specify mass flows for each phase.
	Phase Volume Flow	Specify volume flows for each phase.
	Species Mass Frac	Split each species by mass fraction.
	Species Mass Flow	Specify mass flows for each species.
	Demand Mass Flow	Specify demand mass flows.
	Phase Recovery	Recover a fraction of a chosen phase to a particular stream. NOTE: This option is only available for models with only two output streams.
	Solids Recovery	Recover a fraction of solids to a particular stream. NOTE: This option is only available for models with only two output streams.
	Water Recovery	Recover a fraction of water to a particular stream. NOTE: This option is only available for models with only two output streams.
	Gas Vent	Recover a fraction of gases to a particular stream. NOTE: This option is only available for models with only two output streams.
	Target Stream	Available from Build 139.32925. Specify a single stream for all flow to exit by.
Feed.MassFlow / Qm	Feedback	Available from Build 139.31388. The mass flow of the mixture before splitting of streams.
Feed.Temperature / T	Feedback	Available from Build 139.31388. The temperature of the mixture before splitting of streams - this is the temperature in the unit.
OPERATION - General
		This method allows the user to configure each outgoing stream using mixture of methods. This method is required if a tie exist within a flash train configuration. See topic Tie in Flash Train For method, variable list and some examples for the General Operation please see SplitFlow - General Operation. For a short video on how the General operation works please see YouTube link
OPERATION - Mass Frac
		This option allows the user to specify the mass percentage split to (n-1) streams. All of the outgoing streams will have the same composition as the material in the unit. All of the streams leaving the unit will be displayed on the access page. However, the last stream in the list cannot be configured, the user may use the priority field to select which stream should be configured. For a short video on how the Mass Fraction split works please see YouTube link
Order	Display	The actual stream solving order of priority.
Priority	Drop list	Lets the user select the stream solving order.
Split	Input	Allows the user to specify the fraction of the total mass which is to be directed to this stream.
OPERATION - Mass Flow
		This option allows the user to specify the mass flow to (n-1) streams. All of the outgoing streams will have the same composition as the material in the unit. All of the streams leaving the unit will be displayed on the access page. However, the last stream in the list cannot be configured, the user may use the priority field to select which stream should be configured. When solving, the model will try and satisfy the requirements of the stream with the lowest order number, and then the next lowest, etc. For a short video on how the Mass Fraction split works please see YouTube link
Order	Display	The actual stream solving order of priority.
Priority	List	Lets the user select the stream solving order.
Flow	Input	Allows the user to specify the mass flow of this stream.
Target	Tickbox	If this is ticked (On) then the user will NOT receive warning messages if the user specified requirements for this stream are not met, i.e. it is only a target.
QmErr	Display	Displays the difference between the mass flow specified by the user and the actual mass flow of the stream.
OPERATION - Volume Frac
		This option allows the user to specify the volume percentage split to (n-1) streams. All of the outgoing streams will have the same composition as the material in the unit. All of the streams leaving the unit will be displayed on the access page. However, the last stream in the list cannot be configured, the user may use the priority field to select which stream should be configured. The data fields are the same as for the Operation - Mass Frac option except that the specified Split is the fraction of the total volume rather than the total mass.
OPERATION - Volume Flow
		This option allows the user to specify the volume flow to (n-1) streams. All of the outgoing streams will have the same composition as the material in the unit. All of the streams leaving the unit will be displayed on the access page. However, the last stream in the list cannot be configured, the user may use the priority field to select which stream should be configured. When solving, the model will try and satisfy the requirements of the stream with the lowest order number, and then the next lowest, etc.
Order	Display	The actual stream solving order of priority.
Priority	Drop list	Lets the user select the stream solving order.
VFlow	Input	Allows the user to specify the volume flow of this stream.
Target	Tickbox	If this is ticked (On) then the user will NOT receive warning messages if the user specified requirements for this stream are not met, i.e. it is only a target.
QvErr	Display	Displays the difference between the volume flow specified by the user and the actual volume flow of the stream.
OPERATION - Phase Mass Frac
		This option allows the user to specify the mass percentage split for the different phases reporting to (n-1) streams. All of the streams leaving the unit will be displayed on the access page. However, the last stream in the list cannot be configured, the user may use the priority field to select which stream should be configured. For a short video on how the Phase Mass Fraction split works please see YouTube link
PhaseSpec	Drop List	Allows user to choose either Total phases (solids, liquids and vapours) or Individual phases.
Order	Display	The actual stream solving order of priority.
Priority	Drop list	Lets the user select the stream solving order.
If Total is chosen for the PhaseSpec, then the user will have the following fields for each stream:
Solids	Input	Allows the user to specify the mass fraction of the total solids which is to be directed to this stream.
Liquids	Input	Allows the user to specify the mass fraction of the total liquids which is to be directed to this stream.
Vapours	Input	Allows the user to specify the mass fraction of the total gases which is to be directed to this stream.
If Individual is chosen for the PhaseSpec, then the fields will be the same except instead of Solids, Liquids and Vapours, the user will be able to specify fractions for each individual phase defined in the project (for example, aq (aqueous), o (organic), sl (slag), etc.).
OPERATION - Phase Mass Flow
		This option allows the user to specify the mass flow for each of the different phases reporting to (n-1) streams. All of the streams leaving the unit will be displayed on the access page. However, the last stream in the list cannot be configured, the user may use the priority field to select which stream should be configured. When solving, the model will try and satisfy the requirements of the stream with the lowest order number, and then the next lowest, etc. For a short video on how the Phase Mass Flow split works please see YouTube link
Order	Display	The actual stream solving order of priority.
Priority	Drop list	Lets the user select the stream solving order.
Solids	Input	Allows the user to specify the mass flow of solids in this stream.
Liquids	Input	Allows the user to specify the mass flow of liquids in this stream.
Vapours	Input	Allows the user to specify the mass flow of gases in this stream.
Target	Tickbox	If this is ticked (On) then the user will NOT receive warning messages if the user specified requirements for this stream are not met, i.e. they are only targets.
QmErr	Display	Displays the difference between the total mass flow specified by the user (sum of all three phases) and the actual total mass flow of the stream.
OPERATION - Phase Volume Flow
		This option allows the user to specify the volume flow for each of the different phases reporting to (n-1) streams. All of the streams leaving the unit will be displayed on the access page. However, the last stream in the list cannot be configured, the user may use the priority field to select which stream should be configured. The data fields are the same as for the Operation - Phase_MassFlow option except that the inputs specified are volume flows instead of mass flows. The QvErr field displays the difference between the total volume flow specified by the user (sum of all three phases) and the actual total volume flow of the stream.
OPERATION - Species Mass Frac
		This option allows the user to specify the mass percentage split for the individual species reporting to (n-1) streams. All of the streams leaving the unit will be displayed on the access page. However, the last stream in the list cannot be configured, the user may use the priority field to select which stream should be configured. The data fields are similar to the Operation - MassFrac option except that fractions are specified for each individual species rather than for the whole stream. For a short video on how the Species Mass Fraction split works please see YouTube link
OPERATION - Species Mass Flow
		This option allows the user to specify the mass flow for each individual species reporting to (n-1) streams. All of the streams leaving the unit will be displayed on the access page. However, the last stream in the list cannot be configured, the user may use the priority field to select which stream should be configured. The data fields are similar to the Operation - Phase_MassFlow option except that flows are specified for each individual species rather than each phase. The QmErr field will display the difference between the total mass flow specified by the user (sum of all species) and the actual total mass flow of the stream.
OPERATION - Demand Mass Flow
		This option is not available for Dynamic projects. The unit should have a Feeder (or similar demand source Unit model) with 'Demand' enabled upstream of the unit for this functionality to operate correctly. Please see Demand for more information on the Demand functionality in SysCAD. All of the outgoing streams will have the same composition as the material in the unit. When solving, the model will try and satisfy the requirements of the stream with the lowest order number, and then the next lowest, etc. If Demand.SpecifyTotal is used, the unspecified stream(s) will be calculated last and any residual flow will be split evenly between them (if applicable).
Demand.SpecifyTotal	Tick Box	This option allows the user to specify the Total Demand mass flow and up to n-1 individual stream flows. When the Total flow is specified, at least one stream needs to be * (unspecified). When not used, all n individual output stream flows must be specified.
Demand.TotalQmReqd	Input	Only visible if Demand.SpecifyTotal option is selected. Allows the user to input the total Demand flow.
Demand.TotalQmErr	Display	Available from Build 139.32925. Only visible if Demand.SpecifyTotal option is selected. Displays the flowrate error between the total demand and the current feed flowrate.
Order	Display	The actual stream solving order of priority.
Priority	List	Lets the user select the stream solving order.
QmReqd	Input	Allows the user to specify the Demand mass flow to this stream. Enter * (unspecified) for the balance stream(s) when using Demand.SpecifyTotal.
QmErr	Display	Displays the difference between the Demand mass flow specified by the user and the actual mass flow of the stream.
OPERATION - Phase Recovery
		NOTE: This option is only available for models with two output streams only (n = 2). The user chooses the stream (e.g. overflow, underflow), phase recovered (i.e. solids, liquid or gas), then specifies the split and composition for that particular phase in the chosen stream. For example, if the process unit represents a filter, the user can specify that the recovery of solids is 90% and the filter cake contains 80% solids, (20% moisture).
Phase	Drop List	The phase to be recovered (solid, liquid or gas)
Stream	Drop List	The stream which the user wishes to specify the fraction and composition.
Fraction	Input	The (mass) fraction of the chosen phase which will be sent to the chosen stream. In the above example, we are sending 90% of the feed solids to the specified Stream.
Composition	Input	The (mass) fraction of the chosen phase in the chosen stream. The fractions of the other phases (other than the phase to be recovered) will be automatically adjusted in order to achieve this composition. In the above example, we are requesting the chosen stream to be 80% solids.
OPERATION - Solids Recovery
		This option is only available for models with two output streams only (n = 2). The user chooses the stream where solids is to be recovered, then specifies the split and composition for the stream. For example, if the process unit represents a cyclone, the solids recovery stream can represent the cyclone U/F, where 50% of the feed solids will be sent to the U/F, and the U/F has 65% solids by composition. (35% moisture).
Stream	Drop List	The stream which the user wishes to specify the fraction and composition.
Fraction	Input	The (mass) fraction of the solid phase which will be sent to the chosen stream. In the above example, we are sending 50% of the feed solids to the specified Stream.
Composition	Input	The (mass) fraction of the solid phase in the chosen stream. The fractions of the other phases (other than the solid phase) will be automatically adjusted in order to achieve this composition. In the above example, we are requesting the chosen stream to be 65% solids.
OPERATION - Water Recovery
		This option is only available for models with two output streams only (n = 2). This method can be used to simulate a simple water treatment (RO) facility, where user specifies the water recovery rate and Impurities removal efficiency. Or it can be used to represent any other simple process where water is separated out from a stream. If gas or solids are present in the feed, they will be sent to the other stream (brine), the specified stream will only contain water + other liquid species.
ProductStream / Stream	Drop List	The stream which the user wishes to represent the clean water stream. (The other stream will be the brine)
Yield	Input	The (mass) fraction of water to be recovered. In the above example, we are sending 75% of the feed water to the Product Stream.
Efficiency	Input	The (mass) fraction of other liquid compounds removed. In the above example, we are requesting 95% of all other liquid compounds in the feed be removed and sent to the brine. That means, 5% of other liquid compounds present in the feed will be in the water product stream.
OPERATION - Gas Vent
		This option is only available for models with two output streams only (n = 2). This method is used to send gaseous components to the vent.
VentStream / Stream	Drop List	The stream which the user wishes to represent the vent stream.
Fraction	Input	The (mass) fraction of all gases in the feed to be sent to the vent. In the above example, we are sending 90% of the feed gaseous compounds to the specified Stream.
OPERATION - Target Stream
		Available from Build 139.32925. This method is used to send all flow to a single outlet stream. The chosen Target Stream can be set from a General Controller as a string by setting the Stream tag, or as a number by setting the StreamIndex tag. The index of each stream, and the order in the droplist, is based on the priority setting for each stream.
Stream	Drop List	The stream which the user wishes to send all flow to. Can also be changed via StreamIndex.
StreamIndex	Input	The index of the stream which the user wishes to send all flow to. The index of each stream is based on the priority setting for each stream. Can also be changed via Stream droplist.
Order	Display	The actual stream index.
Priority	Drop list	Lets the user select the stream index for each outlet stream.

Hints and comments

1. If there are n streams leaving the unit, then the user may control (n-1) streams. The nth stream must be free to balance the incoming and outgoing flows.
   • For example, if there are 3 outgoing streams, then the user may configure 2 streams, and the 3^rd stream will be the balance stream.
2. The only exception to this rule is if the user selects Operation = 'Demand Mass Flow', in which case the user must set the Demand flow for ALL outgoing streams.
3. It is strongly recommended that the user sets the priority field for all configured streams in the GM to avoid order swapping. (see the following points)
4. It is useful (and recommended) to set the Priority of one of the streams to "Last" so that it remains last (balance stream) as any other streams are added/removed.
5. If the user configures the SplitFlows GM, and then at a later stage adds or removes a stream from the unit operation containing the GM, this may have an impact on the GM configuration. It is recommended that the user checks the GM settings every time a stream change is made.
6. If the GM configuration data is read in from MS Excel or text files, it is recommended that the priority field be included as part of the settings.
7. For users using the "Species Mass Frac" split method, it may be easier to use a PGM file to assist with the setting of the species, please see PGM Examples - PGM Class to Set Species Splits for pre-defined PGM functions and classes.
8. Users may Find or Access each link listed in the Splitter section by clicking on the binoculars or magnifying glass displayed next to each link name - as shown in the diagram below: