A cubic equation of state: relation between binary interaction parameters and infinite dilution activity coefficients

Abstract

Twu, C.H., Bluck, D., Cunningham, J.R. and Coon, J.E., 1992. A cubic equation of state: relation between binary interaction parameters and infinite dilution activity coefficients. Fluid Phase Equilibria, 72: 25-39. A modified Redlich-Kwong cubic equation of state (CEOS) is applied to the calculation of phase equilibria for highly non-ideal systems. Owing to the new mixing rule used in the CEOS, the physical meaning of the binary interaction parameters in the CEOS can be explained in terms of infinite dilution activity coefficients. Equations relating the binary interaction parameters in the equation of state to the infinite dilution activity coefficients are presented. A robust technique is proposed for obtaining the interaction parameters without regressing PTxy data. The equation of state with the binary interaction parameters derived from the infinite dilution activity coefficients is suitable for the process design of separation processes, especially for environmental concerns, which require prediction of high purity products. The results of calculations are compared with experimental PTxy data.