Configure the property options for a Fluid Type that uses the Ideal method

The available property options depend on the option that you select in the Phases list for your Fluid Type. You can find the Phases list in the System section of the Fluid Editor. You can select one of the following options in the Phases list:

• Vapor Only – Only the vapor phase is present. There are no equilibrium calculations.

• Liquid Only – Only the liquid phase is present. There are no equilibrium calculations.

• Vapor/Liquid (VLE) – Both the liquid phase and the vapor phase are present. The software performs equilibrium calculations to determine the composition and properties of each phase.

• Vapor/Liquid/Water (VLWE) – There are three phases present: the vapor phase and two immiscible liquid phases where one of the liquid phases is mostly water. The software performs equilibrium calculations to determine the composition and properties of each phase.

• Vapor/Liquid1/Liquid2 (VLLE) – There are three phases present: the vapor phase and two immiscible liquid phases.

The default values for the property options depend on the selected System method in the System section.

Configure the property options

1. Open the Fluid Type in the Fluid Editor if the Fluid Type is not already open.

2. Expand the Property Options section if it is not already visible.

   

3. If the option selected in the Phases list in the System section includes a vapor phase, in the Vapor Enthalpy list, select the method that you want to use for the vapor enthalpy calculations.

   The method that you select in the Vapor Enthalpy list overrides the vapor enthalpy calculations from the selected System method. See Effects of specifying thermodynamic method overrides for more information.

4. If the option selected in the Phases list in the System section includes a liquid phase, in the Liquid Enthalpy list, select the method that you want to use for the liquid enthalpy calculations.

   The method that you select in the Liquid Enthalpy list overrides the liquid enthalpy calculations from the selected System method. See Effects of specifying thermodynamic method overrides for more information.

5. In the Enthalpy/Entropy Route list, select System to use the system enthalpy basis and reference state for all components in the Fluid Type, or select Custom to specify your own enthalpy basis and reference state for each component.

   The Enthalpy Basis, Ref T, Ref H, and Phase Ch T columns appear in the Component List section when you select Custom. You can use these columns to change the enthalpy calculation route and reference state for each component. See Changes to the enthalpy basis and reference state for components and Enthalpy calculations for liquid activity methods for more information.

   

6. (Optional) If you selected the Use Henry's Law checkbox in the Equilibrium Options section of the Fluid Editor, select the Include Heat of Absorption in Liquid Enthalpy Calculations checkbox to calculate the heat of absorption when AVEVA Process Simulation performs the liquid enthalpy calculations.

   The Include Heat of Absorption in Liquid Enthalpy Calculations checkbox is selected by default.

   See Heat of absorption for more information.

7. (Optional) Select the Include Liquid Enthalpy Pressure Adjustment checkbox to add a pressure adjustment to the liquid enthalpy calculations to more accurately calculate the liquid enthalpy at high pressures.

   The pressure adjustment applies only to components that are not solids, ions, or Henry's solutes. At low and medium pressures, the contribution of the pressure adjustment is minimal. However, at high pressures, the pressure adjustment may significantly impact your enthalpy results. See Enthalpy calculations for liquid activity methods for more information.

8. If the option selected in the Phases list in the System section includes a liquid phase, in the Liquid Density list, select the method that you want to use for the liquid density calculations.

   The method that you select in the Liquid Density list overrides the liquid density calculations from the selected System method. See Effects of specifying thermodynamic method overrides for more information.

   If you set the Liquid Density option to Rackett, the Rackett Data Banks area appears. Similarly, if you set the Liquid Density option to COSTALD, the COSTALD Data Banks area appears.

   If you want to use custom data banks of Rackett data or COSTALD data, do the following:

   1. In the <method> Data Banks area, select Expand.

      The Selected <method> Banks and Available <method> Banks lists appear along with controls to add, remove, and move data banks in the Selected <method> Banks list.

      

      

   2. In the Available <method> Banks list, select the desired data bank, and then select Add bank to Selected Banks list .

      The data bank appears in the Selected <method> Banks list, which lists the data banks that the Fluid Type uses.

   3. Repeat step b until you have added all the desired data banks.

   4. (Optional) Select Collapse.

      The <method> Data Bank area collapses to only the Selected <method> Banks list.

   If you set the Liquid Density option to Library, the Liquid Density Mixing Rule list appears. In the Liquid Density Mixing Rules list, you can select which mixing rule the software uses to calculate the bulk liquid density of the fluid:

   • Additive Model Volumes

   • Quadratic Mixing Rule (VLQMR)

   See Quadratic mixing rule for liquid molar volume (VLQMR) for more information.