Measurements of vapor–liquid equilibrium in both binary carbon dioxide–ethanol and ternary carbon dioxide–ethanol–water systems with a newly developed flow-type apparatus

Abstract

Vapor–liquid equilibria in binary carbon dioxide–ethanol systems and ternary carbon dioxide–ethanol–water systems were studied at temperatures ranging from 333 to 373K and pressures up to 12MPa with arbitrary feed compositions to the ternary systems. In experimental, a system coupled with two back-pressure regulators was newly adopted, which gave flow rate of each gaseous and liquid phase to be alternately regulated by temporal difference and thus also gave a continuous flow rate in each phase at equlilbirum conditions. The results showed that the equilibrium data obtained in the both systems given by the constructed new apparatus agreed well with literature data supported by the conventional analytical methods. Among the conventionally-proposed equation of states (EOS) adopted to the obtained data, the Peng–Robinson EOS coupled with modified Huron–Vidal second mixing rule was found to be feasible for predicting the equilibrium data in the both systems.