Correlation of multiphase equilibria for asymmetric mixtures by a unified model.

Abstract

The simple DDLC-EOS unified model proposed in the previous paper was extended to describe the multiphase equilibrium behavior of highly asymmetric mixtures.Liquid–liquid equilibrium data of 25 binary and 5 ternary systems as well as vapor–liquid–liquid equilibrium data of five binary systems were correlated with this model and the Soave–Redlich–Kwong equation.Results show that for systems consisting of associating substances, fitting accuracies of the proposed model have been significantly improved.For systems of alkanes or alkylbenzenes with carbon dioxide or ethane as a common component, the average deviations of this model were also found to be lower than those of the conventional method with either temperature-independent or temperature-dependent binary interaction parameters.