DEVELOPMENT AND EXTENSION OF PSRK UNIQUAC MODEL TO METHANE AND NITROGEN GASES/

Two successful procedures for matching the equation of state (EOS) and the excess Gibbs energy model at zero pressure belong to Michelsen [M .L. Michelsen, Fluid Phase Equilibria, 60 (1990) 213] and Holderbaum-G mehling [T. Holderbaum, J. Gmehling, Fluid Phase Equilibria, 70 (1991) 251]. These procedures lead to volume independent mixing rules for th e mixture parameter a. Michelsen proposed the MHV1 and MHV2 mixing rul es and Holderbaum-Gmehling proposed the PSRK mixing rule. Keshtkar et al. [A. Keshtkar, F. Jalali, M. Moshfegian, Fluid Phase Equilibria, 14 0 (1997) 107] demonstrated the utility of these mixing rules together with UNIFAC and UNIQUAC models for the prediction of high-pressure vap or-liquid equilibrium (VLE) of CO2-binary systems. Also, they showed t hat the PSRK/UNIQUAC model gives better VLE results than other models. In this paper, we develop and extend the above model to methane and n itrogen gases. For this purpose, it is required that the missing inter action parameters of model are fitted with experimental VLE data. The VLE calculations show that good agreement between calculated results a nd experimental data can be produced by using the obtained parameters. (C) 1998 Published by Elsevier Science B.V. All rights reserved.