Thermodynamic properties of the methane-ethane systen

Abstract

Abstract Our recently completed wide-ranging correlations for the thermophysical properties of methane and ethane fluids have enabled us to improve the extended corresponding states calculations for the properties of the binary mixtures. The pure fluid equations are based on the analytic Schmidt-Wagner equation of state and give improved results in the general region of the critical point. We use these pure fluid equations (and a reference fluid for which an equivalent equation is known) to calculate properties and compare with experimental PVT data, isochoric heat capacities, and sound speeds of binary mixtures of methane and ethane. We also examine the properties at the vapor-liquid boundary and compare the representation from the classical extended corresponding states calculations with quantities derived from a scaling theory model. The shape of the binary mixture phase boundary is improved with this model, however our new representation of the single phase properties provides only a slight improvement over models based on modified Benedict-Webb-Rubin pure fluid equations of state.