<i>P</i><i>ρ</i><i>Tx</i> Measurements for Gas-Phase Pentafluoroethane + Propane Mixtures by the Burnett Method

Abstract

In some refrigeration-based applications, hydrocarbons (HCs) are expected to be promising long-term alternative refrigerants because of their zero ozone depletion potential (ODP) and negligible global warming potential (GWP) values. But there exists a serious disadvantage that they are flammable. Despite their flammability, however, commercial demands for HCs are increasing not only in several European countries but also in southeast Asia. On the other hand, the flammability is considered a major issue in U.S.A. and Japan. To suppress the flammability, blended mixtures of HCs with nonflammable HFCs are considered. As one of such mixtures, pentafluoroethane (R-125) and propane (R-290) mixtures are dealt with in the present study. Although the thermodynamic properties of each single component have been studied rather extensively, there is no study reported on those of this binary system. Accordingly, we have measured the gas-phase P ρ Tx properties of the binary R-125 (1) + R-290 (2) system by using the Burnett isothermal−isochoric coupling method. The present measurements cover an extensive range of temperatures (305 to 380 K), pressures up to 4.5 MPa, and densities up to 2.5 mol·dm - 3 for the binary systems with four different mole fractions of x 1 = 0.00, 0.29, 0.50, and 0.75, respectively. The present paper discusses the gas-phase P ρ Tx properties for the first time regarding the present binary mixtures at their selected compositions.