Isothermal Vapor–Liquid Equilibrium of the Binary Mixture Difluoromethane (R32) + Octafluoropropane (R218) at Temperatures from 253.150 to 283.150 K

Abstract

The data for the isothermal vapor–liquid equilibria of a binary mixture of difluoromethane (R32) and octafluoropropane (R218) were obtained from 253.150 to 283.150 K using a vapor phase single recirculation. A model combining the Peng–Robinson equation, the modified Huron–Vidal two-order mixing rule, and the nonrandom two-liquid activity coefficient was used to correlate the vapor–liquid equilibrium data. The mean absolute relative differences of pressure (0.81%) and vapor phase mole fraction (0.011%) of the empirical results and the proposed model were calculated to evaluate its validity. According to the empirical and calculated results, azeotropic vapor–liquid equilibrium (VLE) behaviors can be observed.