Some Observations Regarding the Association Kernel of SAFT-VR-Mie. Is the Molecularly Inspired Contribution Always Necessary?

This study compares one relatively simple analytical and two unequally sophisticated molecularly inspired associative contributions to the Helmholtz free energy of SAFT-VR-Mie equation of state in predicting the thermodynamic properties of pure water and the global phase behavior of water-hydrocarbon (alkanes, alkenes, and aromatics) systems in the entire thermodynamic phase-space. The classical van der Waals one-fluid mixing rules with zero values of the binary adjustable parameters are implemented. Although this entirely predictive implementation is particularly challenging, the considered approaches can be characterized by a satisfactorily good accuracy. However, despite the expectations, the most sophisticated molecular-inspired association kernel does not exhibit an overall advantage not only comparing with its less complicated version, but also with the substantially simpler analytical approach. Consequently, the current results indicate that the advanced molecular background does not necessarily guarantee an improvement of the overall robustness and reliability in estimating actual thermodynamic data.