CAPE-OPEN

The liquid-vapor and liquid-liquid phase equilibria (no solids in my application at the moment) can be calculated from Antoine equation and activity coefficient model such as NRTL or e-NRTL respectively. The Redlich-Kister equation is only to utilize excess property concept for mixture properties of interest relevant to heat exchanger design.

I do not think many softwares deliver e-NRTL. If this is a requirement of your system, you choices rapidly diminish. Indeed AspenProperties comes to mind.

e-NRTL although a better representation is not a requirement. actually, NRTL should be sufficient for modeling purposes for the type of analysis i am after. It will be great if the simple or temperature corrected Redlich-Kister mixing model can be incorporated as a selectable option for main thermophysical properties (rho, eta, cp, k, sigma) in "Configure TEA" as part of a planned update.

I am not sure what the best setup would be for this as the number of parameters that is required seems to be rather variable. In addition there should be some sort of GUI to enter these parameters presumably.

I can provide example code for a property calculation routine, but via this route you cannot easily add the pure component values in CAPE-OPEN v1.1. Some back ground, CAPE-OPEN 1.0 had a 'pure' vs 'mixture' calculation type, which was largely unused. Additional confusion arose because quite often the pure calculations would be ideal, e.g. some sort of correlation, whereas the mixture calculations are not, and with the mixture calculations being a different model than pure calculations, pure calculations gave a different result that mixture calculations at pure composition, e.g. X = [ 0, 1, 0, 0, ...]. But in this context that might be exactly what you want, provide a mixture model for which you can issue a pure calculation that will get just correlated values for the pure compound.

However, I presume your compound list is rather limited and you could also simply provide the pure compound data internally to your calculation routine.

Would you like me to provide example code (COBIA based) for a Property Routine that does a mixture calculation for a particular property?

The redlich-kister model for liquid thermophysical properties can be implemented similar to enthalpy ideal+excess model with ideal coming for molar or mass mixing rule. The empricial parameters can be supplied implemented in a way similar to NRTL or other models requiring parameters for computing mixture properties under the interaction parameters tab. A maximum of six or seven constants can be defined with N/A indicating unused constants and the dimension indicating the relevant excess property. This will avoid need of a separate GUI for specifying the inputs of the Redlich-Kister model. The model can be expanded for multi-component solutions utilizing the interaction parameter concept (table 1 in https://link.springer.com/article/10.1007/BF02648364).

Yes, the mixture model would be the reference for both pure and mixture compositions since the excess model parameters will be obtained utilizing mixture data while specifying a suitable pure component model in the regression model.

Regarding COBIA code, i assume it would be in either VB or C++ both of which i am now not familiar with. however, Would this subroutine be accepted in the external subroutine tab of "Configure TEA"?

You may want to make contact with the team at Technische Universität Berlin that develops MOSAICmodelling. In a , the capabilility of MOSAICmodelling to automatically generate derivatives was thought (see section 7) as a possible way to generate CAPE-OPEN Property Packages starting from a equation of state (Z as a function of P, T,...) and deriving the properties of interest in process simulation from there. Dr Erik ESCHE should be contacted on that, to figure out if this idea has been put in action.
MOSAICmodelling has been used to from the description through equations of the calculation method of the Unit Operation.