Development of Soave–Redlich–Kister Equation of State and Vapor–Liquid Equilibrium Modeling For Polar Pure Compounds and Binary Mixtures

By combining a dipole expression with an Soave–Redlich–Kister, SRK, equation of state, a new SRK equation of state is developed. a0, ci\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$c_{i}$$\end{document}, b and bp, the parameters of this equation, were optimized for pure compounds by using experimental data of vapor pressure and saturated liquid density. Examining the modeling results for the dipolar compounds shows that this equation correlates well with their behavior. The physical properties of pure compounds, including the heat capacity, speed of sound, Joule–Thomson coefficient and enthalpy of evaporation were calculated using this equation of state, and were in good agreement with the experimental results. By combining a dipole expression with the SRK equation, a good improvement in the prediction of the Joule–Thomson coefficient of the liquid phase was made. Also, vapor–liquid equilibrium calculations were performed for four binary systems by using this SRK equation, which shows that the prediction of the system behavior by the revised SRK equation was improved.