Investigation of Bulk and Interfacial Properties for Nitrogen and Light Hydrocarbon Binary Mixtures by Perturbed-Chain Statistical Associating Fluid Theory Combined with Density-Gradient Theory

Abstract

The perturbed-chain statistical associating fluid theory (PC-SAFT) and density-gradient theory (DGT) are used to construct an equation of state (EOS) for the phase behavior of the binary mixtures of nitrogen and light hydrocarbons. With the molecular parameters and influence parameters respectively regressed from bulk properties and surface tensions of pure fluids as input, both the bulk and the interfacial properties for binary mixtures are investigated. The calculated surface tensions of nitrogen−pentane, nitrogen−hexane, nitrogen−heptane, nitrogen−octane, nitrogen−decane, and nitrogen−toluene binary mixtures are satisfactory as compared to the experimental data. Our results show that PC-SAFT combined with DGT is able to describe the interfacial properties of the binary mixtures of nitrogen−light hydrocarbons in wide pressure range and illustrate the influences of temperature, pressure, and bulk properties on the interfacial properties.