Configure a compositional Fluid Type that uses an equation of state or liquid activity coefficient method

These Fluid Types use Compositional as their Thermo Type.

Configure a compositional Fluid Type that uses an equation of state or liquid activity coefficient method

1. Open the Fluid Type in the Fluid Editor.

2. Expand the System section.

3. In the System list, select one of the following equations of state or liquid activity coefficient (LACT) methods, which AVEVA Process Simulation uses to model the system and perform all thermodynamic calculations:

   • Soave-Redlich-Kwong (SRK)

   • Peng-Robinson (PR)

   • SRK-Modified Panag.-Reid (SRKM)

   • PR-Modified Panag.-Reid (PRM)

   • SRK-Huron-Vidal (SRKH)

   • PSRK (SRK-Holderbaum Gmehling)

   • Non-Random Two-Liquid (NRTL)

   • Universal Quasi-Chemical (UNIQUAC)

   • Dortmund UNIFAC

   • Wilson

   • Electrolyte NRTL

   See Thermodynamic methods by name for more information on the differences between the equations of state and LACT methods.

   

4. (Optional) In the data bank area, select Expand and add any custom data banks or additional system data banks that you want to use in your Fluid Type.

   The name of the data bank area depends on the selected System method. You add or remove data banks of interaction data to your Fluid Type in one of the following data bank areas, which are mutually exclusive to each other:

   • Binary Interaction Banks – Applies to the following equations of state and LACT methods:

     • SRK

     • PR

     • SRKM

     • PRM

     • SRKH

     • PSRK when the Excess Gibbs Energy Method selection is NRTL in the Equilibrium Options section of the Fluid Editor

     • NRTL

     • UNIQUAC

     • Wilson

   • Group Information Banks – Applies to the following equation of state and LACT method:

     • PSRK when the Excess Gibbs Energy Method selection is UNIFAC in the Equilibrium Options section of the Fluid Editor

     • Dortmund UNIFAC

   • Unary, Binary, Ternary, and Quaternary Interaction Banks – Applies only to the Electrolyte NRTL method.

     Currently, Electrolyte NRTL fluids use the System:ELECTRL data bank by default. Because AVEVA Thermodynamic Data Manager currently doesn't support electrolyte data banks, we recommend that you do not remove this data bank from the Fluid Type in the Unary, Binary, Ternary, and Quaternary Interaction Banks area. If you want to use custom data banks of electrolyte interaction data, please contact AVEVA Process Simulation customer support for more information on how to do this.

   See Data banks for a Fluid Type for more information on the controls for adding, removing, and moving data banks in the Fluid Type.

5. In the Phases list, select the phases that you want the thermodynamic calculation system to model; for example, if you model a flare process where liquids are not present, select Vapor Only.

6. (Optional) If you set the Phases list to Vapor/Liquid (VLE), select the Include non-equilibrium solid components to include any solid components in the composition calculations of the liquid phase.

   See Specify components as solids in a compositional Fluid Type for more information.

   

7. (Optional) If you set the Phases list to Vapor/Liquid (VLE), select the Apply high pressure VLE adjustments option that best suits your system:

   • Off: The software uses the standard VLE calculations and does not adjust the algorithm for determining the k-values of the phase equilibria. This is the default option.

   • Auto: The software adds another layer to the algorithm for determining the k-values of the phase equilibria. When the process conditions are at high pressures near or in the supercritical region, the software uses modified k-value calculations that produce more accurate results. This change significantly improves the robustness for high-pressure systems. This robustness improvement is especially true for systems in the supercritical phase region, where it is difficult to determine and characterize the true phase.

   • Force (Experimental): The software forces all flashes to use the modified k-value calculations for high-pressure or supercritical conditions regardless of the process conditions. This change is an extreme alteration, and you should use this option only in an experimental capacity. We recommend that you do not use this option unless your simulation still does not solve when the Auto option is selected. You should externally verify all results before you use them in any production applications.

   Currently, you can use the Apply high pressure VLE adjustments option only when you use one of the equations of state as the System method.

8. (Optional) If you set the Phases list to Vapor/Liquid/Liquid (VLLE), in the Liquid/Liquid Algorithm list, select the algorithm that you want to use to characterize the liquid-liquid equilibrium (LLE) phases, including the key component identification:

   • Original — A default algorithm that provides accurate and robust LLE identification.

   • Modified Original — An improved version of the Original algorithm that includes better initialization logic. This algorithm is currently in the experimental phase.

   • Embedded K — An algorithm that uses different open-form equations for the vapor-liquid-liquid equilibrium (VLLE) than the Original algorithm. This algorithm maintains the K-values by rigorously solving the VLLE flash calculations and providing the corresponding sensitivities. This algorithm is currently in the experimental phase.

   All Fluid Types initially use the Original algorithm by default. Because the different LLE algorithms can produce significantly different results, we highly recommend that you capture a snapshot of the simulation before you change the selected LLE algorithm for a Fluid Type.

   We also recommend that you do not select the Embedded K algorithm if a simulation is currently using the Fluid Type.

   See Key components for the liquid phases and Switch between liquid-liquid equilibrium algorithms for more information.

   

9. (Optional) If you set the Phases list to Vapor/Liquid/Water (VLWE), review the option selected in the Water Solubility Option list.

   The Water Solubility Option list indicates the correlation that AVEVA Process Simulation uses to calculate the water solubility (that is, the composition fraction of water) in the hydrocarbon liquid phase. Currently, you cannot change the correlation.

   

10. (Optional) By default, AVEVA Process Simulation uses its own data bank of pure components and pure component data. If you want to override the properties in the default data bank with those in a custom data bank, in the Pure Component Property Override Data Bank box, enter the name of the custom data bank that contains the property data that should be overridden.

    This custom data bank should contain only the components of interest and only data for the property values that you want to override.

11. (Optional) Select the Report Fluid Configuration Warnings and Thermodynamic Calculation Warnings checkbox to see warnings related to the fluid configuration and the thermodynamic calculations.

12. Add components to the Fluid Type and specify any required data.

    See Add a pure or petro component to a compositional Fluid Type for more information.

13. (Optional) Expand the Equilibrium Options section, and then configure the equilibrium options for your Fluid Type.

    See the following sections for more information:

    • Configure the equilibrium options for a Fluid Type that uses an equation of state

    • Configure the equilibrium options for a Fluid Type that uses the NRTL, UNIQUAC, or Wilson method

    • Configure the equilibrium options for a Fluid Type that uses the Electrolyte NRTL method

    • Configure the equilibrium options for a Fluid Type that uses the Dortmund UNIFAC method

14. (Optional) Expand the Property Options section, and then configure the equilibrium options for your Fluid Type.

    See the following sections for more information:

    • Configure the property options for a Fluid Type that uses an equation of state

    • Configure the property options for a Fluid Type that uses a LACT method

15. (Optional) Expand the Transport Mixing Rules section, and then select the desired mixing rule for the following transport properties:

    • Vapor thermal conductivity

    • Liquid thermal conductivity

    • Liquid surface tension

    • Vapor viscosity

    • Liquid viscosity

      See Change the mixing rules for transport property calculations for more information.

16. (Optional) Expand the Method Data section, and then update the thermodynamic data.

    Any changes to the data in this section will override the thermodynamic data from the data banks in the Binary Interaction Banks area. See Overrides for thermodynamic method data for more information.

17. (Optional) Expand the Starting Values section, and then enter the Initial value, Minimum value, and Maximum value for the Pressure and Temperature.