CRITICAL LOCUS, (VAPOR + LIQUID) EQUILIBRIA, AND COEXISTING DENSITIES OF (CARBON-DIOXIDE + PROPANE) AT TEMPERATURES FROM 311-K TO 361-K

Isothermal (vapor + liquid) equilibria and coexisting densities for (carbon dioxide + propane) have been measured at (311.05, 327.75, 344.43, and 361.15) K from the vapor pressure of propane to the critical pressure of the mixture, and the critical locus has thus been determined. Away from the critical locus, our measurements agree within combined experimental uncertainties with those of Reamer, Sage, and Lacey. The measurements confirm the observation of Roof and Baron that the critical pressures reported by Poettmann and Katz and by Reamer et al. are substantially in error. The critical pressures from this study are lower than those of Reamer et al. by as much as 0.785 MPa and of Roof and Baron by as much as 0.034 MPa. The dew- and bubble-points are correlated by three methods, the Soave-Redlich-Kwong (SRK) equation, the DDMIX program of Ely, and the Leung-Griffiths model as modified by Moldover and Rainwater. Except for poor predictions of liquid densities by the SRK equation, all three models provide good correlations of the measurements, but the modified Leung-Griffiths model is superior very near the critical locus. © 1990.