Phase Behavior, Densities, and Isothermal Compressibility of the CO2 + Ethanol + Dichloromethane Ternary System in Different Phase Regions

Abstract

The phase behavior and critical parameters of the CO2 (1) + ethanol (2) + dichloromethane (3) ternary system were determined, and the density of the mixtures was measured in both the subcritical and supercritical regions of the system. The isothermal compressibility (KT) under some typical conditions was calculated using the density data. The data were also calculated using the Peng−Robinson equation of state (PR EOS). The results showed that the density of the mixtures at fixed composition and temperature is very sensitive to pressure as the pressure approaches critical, bubble, and dew pressures in the critical regions (both temperature and composition are close to the critical point of the mixtures). However, the effect of pressure on the density of a subcritical fluid is very limited over the whole pressure range because the composition of the mixture is far from the critical composition.