VLE measurement for binary systems of CO2 + 1,1,1,2-tetrafluoroethane (HFC-134a) at high pressures

Isothermal vapor–liquid equilibrium data for the binary system of carbon dioxide + 1,1,1,2-tetrafluoroethane (HFC-134a) were measured at 323.15, 328.15, 333.15, 338.15 and 343.15 K using a circulation-type equilibrium apparatus in which both vapor and liquid phases were recirculated. The equilibrium compositions of vapor and liquid phases and pressures were reported at each temperature. The measured data were correlated with the Peng-Robinson equation of state (PR-EOS) and the relevant binary parameters were suggested. It was found that this system does not form an azeotrope and the Peng-Robinson equation of state with the Wong–Sandler mixing rule can be used to estimate the thermodynamic properties of this binary system of CO2 (1) + HFC-134a (2).