Measurement and prediction of the bubble/dew point locus in the near-critical region and of the compressed fluid densities of the methanecarbon dioxide-n-butane ternary system

The bubble/dew point locus in the near-critical region, the critical points and the compressed fluid densities of two ternary mixtures of the methanecarbon dioxide-n-butane system were measured in a ROP computer-controlled, mercury-free, high-pressure PVT system. The Soave-Redlich-Kwong (SRK) and Patel-Teja (PT) equation of state (EOS) coupled with different mixing rules were used to predict the experimental VLE data. The average absolute deviations between the predicted and experimental bubble/dew point pressures were less than 2.5 for all the models tested. The PT EOS and the volume-translated SRK EOS proposed by Peneloux and Rauzy [Peneloux, A. and Rauzy, E., 1982. A consistent correction for Redlich-Kwong-Soave volumes. Fluid Phase Equilibria, 8: 7–23] were used to predict the compressed fluid densities, giving satisfactory results.