Override the binary interaction parameters for a Fluid Type that uses the SRKM or PRM equation of state

The Soave-Redlich-Kwong Modified Panagiotopoulos-Reid (SRKM) and Peng-Robinson Modified Panagiotopoulos-Reid (PRM) equations of state (EOSs) use the same formulation for the binary interaction parameters. Therefore, the procedures for overriding the binary interaction parameters for these EOSs are the same.

A Fluid Type can use these EOSs as:

• The main thermodynamic system method

• The vapor equilibrium method in combination with a liquid activity coefficient (LACT) system method

You can override the binary interaction parameters regardless of how the Fluid Type uses the EOS.

The SRKM and PRM tabs in the Method Data section contain a component grid for every possible binary pair in the Fluid Type. Each binary pair has a cell that indicates the status of the binary interaction data:

• If the cell is blank, there is currently no data for the binary pair.

• If the cell has a green badge, the binary interaction data is available and comes from the default or custom data banks.

• If the cell has a function icon , the binary interaction data comes from the default or custom data banks, but the value is calculated from a correlation.

• If the cell has a blue badge, the binary interaction data is available and comes from the user-specified (that is, locally overridden) data values on the SRKM or PRM tab.

Override the thermodynamic data for a Fluid Type that uses the SRKM or PRM EOS

1. In the Fluid Editor, expand the Method Data section, and then select the SRKM or PRM tab depending on which EOS the Fluid Type uses.

2. In the component grid, select the cells for the binary pairs whose binary interaction data you want to change.

   The binary interaction data for those binary pairs appears in the table on the SRKM or PRM tab.

3. In the table, change the binary interaction parameters as desired.

   See the equations preceding the table if you have questions on how the software uses each binary interaction parameter in the method calculations.

   A blue badge appears in the component grid for each binary pair whose data you modify.