High-Pressure Vapor−Liquid and Solid−Gas Equilibria Using a Peng−Robinson Group Contribution Method

Abstract

In this paper, the new excess Gibbs energy mixing rule, which coupled with the consistent form with the quadratic composition dependence of the second virial coefficient and the excess Gibbs energy ( ) at standard zero pressure, has been developed. This proposed mixing rule, combining a Peng−Robinson equation of state with the analytical solutions of groups (ASOG) group contribution method, provide a Peng−Robinson group contribution method (PRASOG). The PRASOG model has predicted the high-pressure vapor−liquid equilibria (VLE) for binary systems containing alcohols, acetone, and water using the available ASOG group pair parameters determined at low pressure with good accuracy. The ASOG parameters have also been shown for 31 group pairs relating to two gas groups, CO2 and CH4, which indicate potential for global warming, using binary experimental high-pressure VLE data in the temperature range 200−600 K. High-pressure VLE have then been correlated for 56 binary systems containing carbon dioxide and/or meth...