Investigation Of The Phase Equilibria And Interfacial Tension For Carbon Dioxide-water Binary Mixtures

An equation of state applicable to the phase behavior of a CO₂-water binary mixture was established based on the perturbed-chain statistical associating fluid theory (PC-SAFT). The binary interaction parameter was regressed by fitting to the experimental data of vapor-liquid and liquid-liquid equilibria, and the correlation agreed well with experiments. The temperature and pressure ranges for vapor-liquid-liquid three phase equilibria of the CO₂-water binary mixture were predicted. The densities corresponding to the coexisting three phases of the triple points and their temperature and pressure dependence were determined.An un-uniform equation of state applicable for the interfacial properties of CO₂-water binary mixture was established by combining the PC-SAFT and the density gradient theory(DGT). With the equilibrium bulk properties as input, the interfacial tensions of CO₂-water binary mixture were correlated and predicted, and the influences of temperature and pressure are illustrated.