Critical locus and vapor-liquid equilibria of HFC32-HFC125 system

We measured vapor-liquid equilibria (VLE) and critical locus for the system of difluoromethane (HFC32)-pentafluoroethane (HFC125) ranging from 318.15 to 349,15 K. Composition differences between vapor and liquid phases on the P-(x-y) diagram were very small. The critical locus can be classified as type I behavior according to the system of van Konynenburg-Scott. The system of HFC32 and HFC125 is unusual in that the larger component in molecular weight has a lower critical temperature and vapor pressure than the smaller component. Using binary interaction parameter m(ij) expressed as a linear function of composition and temperature. we obtained excellent correlation of the experimental data with an extended BWR equation of state. (C) 2002 Elsevier Science B.V. All rights reserved.