Extension of an improved one-fluid conformal solution theory to real fluid mixtures with large size differences

Abstract

Conformal solution theories have been shown to be inadequate as the size ratio of the molecules in a mixture increases. We present an improved van der Waals-1 fluid conformal solution theory which incorporates a correction term developed using statistical mechanical perturbation theory. The correction addresses the effect of different size molecules on the Helmholtz free energy of the mixture. Results of the new model are compared with other conformal solution theories for model Lennard-Jones systems. We also show how to extend the model to perform computations on real fluid mixtures. Results for selected hydrocarbon mixtures are given.