Vapor-liquid equilibria of alternative refrigerants and their binaries by molecular simulations employing the reaction Gibbs ensemble Monte Carlo method

Alternative refrigerants HFC125 (CHF2CF3) and HFC 134a (CF3CH2F) are modeled as a dipolar two-center Lennard-Jones fluid and alternative refrigerant HFC32 (CH2F2) is modeled as a dipolar Lennard-Jones fluid. We calculate vapor-liquid equilibria of these refrigerants by Gibbs-Duhem integration and vapor-liquid equilibria of two binaries (HFC 125 + HFC 134a and HFC 134a + HFC 32) by the reaction Gibbs ensemble Monte Carlo method. Potential parameters of the model are fitted to the critical temperature and vapor-liquid equilibrium data. The predictions are very good, and of comparable accuracy to those obtained using the Wilson and the UNIFAC thermodynamic-based approaches, even though such approaches use experimental mixture information. (C) 2004 Elsevier B.V. All rights reserved.