APPLICATION OF A GENERALIZED BENDER EQUATION OF STATE TO THE DESCRIPTION OF VAPOR-LIQUID-EQUILIBRIA IN BINARY-SYSTEMS

A recently published four-parameter corresponding state generalization of the Bender equation of state is extended to describe fluid mixtures. Interactions between species of different kinds are considered by introducing three temperature-independent binary parameters which were fitted to experimental vapour-liquid equilibrium data. Altogether 71 binary mixtures are treated. Data correlated by the generalized Bender equation are compared with experimental results and with data correlated by the Lee-Kesler-Plocker (LKP) procedure. The generalized Bender equation needs less computing time than the LKP method and gives a better representation of the experimental data, especially when the components differ considerably in molecular size and/or structure, while there is no or only a minor improvement for simple systems such as argon/methane.