Experimental measurements and correlation of vapor–liquid equilibrium data for the difluoromethane (R32) + 1,3,3,3-tetrafluoropropene (R1234ze(E)) binary system from 254 to 348 K

In this study, we present new experimental data of vapor–liquid equilibrium for the binary system difluoromethane (R32) + 1,3,3,3-tetrafluoropropene (R1234ze(E)), measured at 273.14 and 363.32 K and at pressure ranging from 0.1568 to 4.3553 MPa. A "static-analytic"-type apparatus is used to do the measurements, with sampling of the equilibrium phases via capillary sampler (ROLSI®). We used three different models to correlate the data: 1) the Peng–Robinson cubic equation of state combined with the NRTL excess free energy model and Wong-Sandler mixing rules, 2) Helmholtz energy model like the one incorporated in REFPROP 10.0 software and 3) Predictive PPR78 model for which the new group parameter of R32 was adjusted. All of the three models show a very good agreement with the experimental data except for temperature higher that R32 critical temperature.