Plant Model - Species

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FlwSolve Tab	Settings Tab	Audit Tab	Project Tab	RC Tab	Species Tab	Views Tab	Soluble Tab	WaterQuality Tab	Qualities Tab
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Introduction

This tab page on the Plant Model Access Window has a number of parameters that the user may either set or read for Global settings.

Tag (Long/Short)	Input / Calc / Options	Description/Calculated Variables
Calculation Methods
Enthalpy Strategy	Best_Temperature	The method used for energy balance when mixing streams with different properties models that may have different stream enthalpy calculations. Attempt to maintain temperature, adjust enthalpy. Use the outgoing properties enthalpy model when mixing streams. Note that in this case, the enthalpy of the outgoing stream may not be equal to the sum of the incoming stream enthalpies. When mixing two streams of the same temperature, the outgoing temperature will be equal to incoming temperature provided there is no concentration dependence of the enthalpy function.
	Conserve_Heat	The method used for energy balance when mixing streams with different properties models that may have different stream enthalpy calculations. Maintain enthalpy, adjust temperature. In this case the enthalpy of the outgoing stream is guaranteed to equal to the sum of the incoming stream enthalpies.
SaturationCmp	H2O	By default the saturation component used in any VLE blocks will be H2O. The user can override this in the individual VLE block.
	All - H2O	The saturation component used in all VLE blocks will be H2O, the user cannot override this in the individual VLE block.
	component X	By default the saturation component used in any VLE blocks will be component X (any component which is available for VLE). The user can override this in the individual VLE block.
	All - component X	The saturation component used in all VLE blocks will be component X (any component which is available for VLE), the user cannot override this in the individual VLE block.
DefaultSpModel	Display	This displays the default species model as selected in the Project's Configuration File.
Species Property Overrides
SysCAD has a number of different options that the user can select to calculate the properties of water and steam: The default option is to use the IF97 method. This provides accurate simulation results involving steam and water. SysCAD 9.3 includes improved equations for steam in Region 5. The Low Fidelity steam/water equations are much faster. The low fidelity correlations match IF97 closely for models where temperatures and pressures are appropriate. However, there is a significant speed improvement when using the Low Fidelity methods. The Simple equations are less accurate, but suitable for low temperature projects that do not require high accuracy for steam/water calculation.
Species Property Overrides - Liquids
H2O(l).Rho	None	The default method will be used to calculate the water density. This is IF97.
	IF97	The industrial standard IAPWS-IF97 equation will be used for the water density calculation. The default equation.
	LowFid	The Low Fidelity equation will be used for the water density calculation.
	Simple	Simple Water equation will be used for the water density calculation.
H2O(l).Cp	None	The default method will be used to calculate the water specific heat. This is IF97.
	IF97	The industrial standard IAPWS-IF97 equation will be used for the water heat capacity calculation. (The default equation.)
	LowFid	The Low Fidelity equation will be used for the water heat capacity calculation.
	Simple	The Simple Water equation will be used for the water heat capacity calculation.
H2SO4(aq).Cp	None	The default equation (KWA) will be used for the sulfuric acid heat capacity calculation.
	Fasullo	The Fasullo equation will be used for the sulfuric acid heat capacity calculation.
	KWA	A constant heat capacity estimated by Kenwalt will be used for the sulfuric acid heat capacity calculation.
	Zaytsev	The Zaytsev equation will be used for the sulfuric acid heat capacity calculation.
Species Property Overrides - Vapours
H2O(g).Rho	None	The default method will be used to calculate the steam density. This is IF97.
	IF97	For Build 138: IF97 - (SysCAD 9.2 version) - The industrial standard IAPWS-IF97 equation will be used for the steam density calculation. (The default equation.) IF97_2 - (Improved equations in Region 5) - The industrial standard IAPWS-IF97 equation will be used for the steam density calculation, with improved equations in Region 5. For Build 139: IF97 - (SysCAD 9.3 Build139 version including improved equations in Region 5) - The industrial standard IAPWS-IF97 equation will be used for the steam density calculation. (The default equation.)
	LowFid	Low Fidelity correlations will be used for the steam density calculation.
	Simple	The Simple equation will be used for the steam density calculation.
H2O(g).Cp	None	The default method will be used to calculate the steam heat capacity. This is IF97.
	IF97	For Build 138: IF97 - (SysCAD 9.2 version) - The industrial standard IAPWS-IF97 equation will be used for the steam heat capacity calculation. (The default equation.) IF97_2 - (Improved equations in Region 5) - The industrial standard IAPWS-IF97 equation will be used for the steam heat capacity calculation, with improved equations in Region 5. For Build 139: IF97 - (SysCAD 9.3 Build 139 version including improved equations in Region 5) - The industrial standard IAPWS-IF97 equation will be used for the steam heat capacity calculation. (The default equation.)
	LowFid	Low Fidelity correlations will be used for the steam heat capacity calculation.
	Simple	The Simple equation will be used for the steam heat capacity calculation.
Water properties below 0C
H2O(l).UseNewLowT.Cp	Tickbox	Available from Build 139. Please see Water and Steam Properties for more detail. If this option is selected, then water Cp, H and S between 235K and 273.15K. For temperatures below 235K (-38.15°C), data is extrapolated. If this option is not selected, then water Cp is extrapolated below 0°C. (This is original method used in Build138 and earlier, retained here for backward compatibility purposes.)
H2O(l).UseNewLowT.Rho	Tickbox	Available from Build 139. Please see Water and Steam Properties for more detail. If this option is selected, then water density between 235K and 273.15K. For temperatures below 235K (-38.15°C), data is extrapolated. If this option is not selected, then water density is extrapolated below 0°C. (This is original method used in Build138 and earlier, retained here for backward compatibility purposes.)
VLE Liquid Phase Change Limits
VLE.XXX.FracToVap.Max (%)	Input	Available from Build 139.31157. XXX is replaced for each VLE species. Used in single component Vapour Liquid Equilibrium (VLE) calculations to define the maximum final fraction of the VLE species in vapour phase versus the total of that species in the liquid and vapour phases. A warning is shown in process units if VLE is limited by this value. Prior to 139.31157, this value was hard-coded at 80%. The default for new projects is 100%. This may be reduced to limit "over-flashing".
VLE.XXX.FracInLiq.Min (%)	Input	Available from Build 139.31157. XXX is replaced for each VLE species. Used in single component Vapour Liquid Equilibrium (VLE) calculations to define the minimum final fraction of the VLE species in the liquid phase versus all other liquid phase species. A warning is shown in process units if VLE is limited by this value. Prior to 139.31157, this value was hard-coded at 20%. The default for new projects is 20% for H2O and 0% for all other species. The exception for water is to ensure correct behaviour of aqueous (aq) species.
Auto Phase Change Equilibrium
PhaseChange@T	Off	Phase change at Temperature will NOT occur automatically. This will be the default (and greyed out) if there is no function defined in the species database.
	On	Phase change at Temperature will occur automatically throughout the project for all species with defined Phase change at Temperature functions in the species database. Please see Phase Change in Species Database for further details. (An example of this is Hematite (Fe2O3(s)) changing automatically from the alpha to the beta form at 427°C.) Do not use this with the FEM model if phases are present, it may for example convert molten liquids (which are stable in a mixture below the melting point) into solids
PhaseChange@MF	Off	Phase change at Mass Fraction will NOT occur automatically. This will be the default (and greyed out) if there is no function defined in the species database.
	On	Phase change at Mass Fraction will occur automatically throughout the project for all species with defined Phase change at Mass Fraction functions in the species database. Please see Phase Change in Species Database for further details. (An example of this is H2SO4 changing automatically from the liquid to the aqueous phase at 98.3% acid)
AutoVLE	Off	Automatic vapour-liquid equilibrium (VLE) will NOT occur automatically. This is the default setting for all upgraded and new projects.
	On	Automatic vapour-liquid equilibrium (VLE) will be enabled in all pipes. The calculations will use the default Saturation species for the calculations. See Vapour Liquid Equilibrium (VLE) for further details.
Standard Properties SpModel Options
DensityCorrection	FracInSolventOnly	The density correction calculations use the mass fraction of individual species in the solvent ONLY. The resulting density of the solution will be HIGHER than using the method below, because the correction factor is greater. Please see Density Correction Methods for a more detailed description.
	FracInAqueousSoln	The density correction calculations use the mass fraction of the individual species in the TOTAL aqueous solution. The resulting density of the solution will be LOWER than using the method above, because the correction factor is smaller. Please see Density Correction Methods for a more detailed description. Note: This method is only valid if the solvent is Water.
BPE_Method	None	No Boiling Point Elevation (BPE) calculations will be performed, i.e. BPE = 0°C in all streams with the Standard Species Model.
	VantHoff	The BPE will be calculated using the equation shown in Boiling Point Elevation and the van't Hoff constants as entered in the Species Database.
BPE_LoLimit	Input	The lower limit for the BPE calculations - usually 0°C. The BPE Limit values are also applied to user data entry for BPE override in VLE.
BPE_HiLimit	Input	The upper limit for the BPE calculations - the default is 20°C, but if the project has concentrated solutions the upper limit may need to be higher.
Species Count
SpeciesCountDetails / SpCountDetails	Display	The Species Properties ($SDB) tag for total species count.
SpeciesCount / SpCount	Display	The total number of species in the project.
SpeciesSolCount / SpSolCount	Display	The number of solid species in the project.
SpeciesLiqCount / SpLiqCount	Display	The number of liquid species in the project.
SpeciesVapCount / SpVapCount	Display	The number of vapour or gas species in the project.
SpUse (Species Use) Available from Build 139. After the project is solved, the list of species used by the project (has flow) can be reported here. User can also copy the list to clipboard for reporting purposes. User should check this list prior to removing a species from the project configuration file to ensure a species with flow is not removed by mistake.
SpeciesInUse	Report Button	Clicking on this button will bring up the following options: Clipboard: Unused - The list of unused species will be added to the clipboard. User can paste the contents of the clipboard in another application such as MS Excel for reporting purposes. Clipboard: Used - The list of the used species, use count, maximum flow in the project etc. will be added to the clipboard. User can paste the contents of the clipboard in another application such as MS Excel for reporting purposes. Clipboard: All - The list of all species, use count, maximum flow in the project etc. will be added to the clipboard. User can paste the contents of the clipboard in another application such as MS Excel for reporting purposes. Message: Unused - The list of unused species will be added to the message window. Message: Used - The list of the used species, use count, maximum flow in the project etc. will be added to the message window. Message: All - The list of all species, use count, maximum flow in the project etc. will be added to the message window.
TestOnStop	Tickbox	If this option is ticked, the species used table will be displayed on the bottom of the page. The values will be updated when the SysCAD solver stops or when the "Refresh Now" button is pressed.
SearchCount	Display	The number of unit operation searched in generating the species used table.
SpFlowCount	Display	The number of species used by the project (with flow).
SpNoFlowCount	Display	The number of species not used by the project (with no flow).
The species used table will be displayed here, each species present in the project will be added as a row. The column headings are described below:
Count	column heading	The species has flow in this number of unit operations (e.g.: pipes, contents).
MaxQm	column heading	The species has shown a maximum flow in this unit operations (tag name shown in Max Tag column).
MaxTag	column heading	The species has shown a maximum flow (flow shown in the MaxQm column) in this unit operations.
Species X	row heading	Each species present in the project will be added as a new row.