1 reply to this topic

[bponcet]

I have a doubt about how to define BIP s (Binary Interaction Parameters) for Peng Robinson - NRTL with LCVM mixing rules in Prode Properties,

the dialog allows to input both Kij (for EOS model) and Aij (for NRTL model),

for mixtures that include hydrocarbons, nitrogen, carbon dioxide plus water, methanol, ethanol etc. my understanding is that I should define Aij values only for binary pairs where NRTL model is required

(for example water-methanol) while all other values are the usual Kij from EOS (hydrocarbons, N2, CO2..) which I load from Prode database.
The doubt is about how Prode Properties selects BIP s when both values (EOS and NRTL) are included (it happens when loading BIPs from database)...

 

thanks !

[marchem]

with LCVM, Huron-Vidal etc. mixing rules,  Prode Properties utilizes the NRTL (or UNIQUAC, WILSON etc.)  parameters when available, differently, the usual EOS Kij

 

see this screenshot including both Kij and Aij values

 

 

note that calculated values are equal to those calculated with the EOS for all binary pairs where NRTL or Wilson or UNIQUAC values are not defined...