Investigation Of The Phase Equilibria And Interfacial Tension For Methane And N-alkane Binary Mixtures

The perturbed-chain statistical associating fluid theory (PC-SAFT) and density-gradient theory were used to describe the phase equilibria and interfacial tension of binary methane-n-alkane mixtures. With the molecular parameters and influence parameters regressed from bulk properties and surface tensions of pure fluids as input, both the bulk and interfacial properties were investigated. The phase equilibria and interfacial tension of the binary mixtures of methane-propane, methane-pentane, methane-heptane and methane-decane were predicted, and the results are satisfactory compared with the experimental data. Our results showed that PC-SAFT combined with density-gradient theory is able to describe the interfacial properties of binary methane-n-alkane mixtures in wide temperature and pressure ranges, and illustrate the influence of the equilibrium bulk properties and chain length of n-alkane molecule on the interfacial properties.