A model based on the equality of chemical potentials for describing the liquid-liquid interfaces of water-hydrocarbons up to high pressures

A reliable model was used to describe the interfacial tension, composition, and density of the liquid-liquid interfaces of water-hydrocarbons. The parachor model was combined with the equality of the chemical potential of components at the interface and the bulk liquid. The fugacity coefficient was used for computing chemical potentials. To compute the fugacity coefficients of the components, various types of equations of state (The Valderrama Patel-Teja, cubic plus association, and the simplified Perturbed-Chain Statistical Association Fluid Theory) were utilized. These models were applied to the temperature and the pressure range of (285.65–423) K and (1–3000) bar, respectively. The adjustable parameters of these models were regressed based on the experimental interfacial tensions of (water/hydrocarbon) binary systems at the pressure of 1 bar. These adjustable parameters were used to predict the interfacial tension, composition, and density of (water/hydrocarbon) binary systems at high pressures. It was found that Valderrama Patel-Teja (AAD% = 1.49) and cubic plus association (AAD% = 2.33) equations of state had the best results for ternary and quaternary systems, respectively. •The present model is successfully applied to the liquid-liquid interfaces of water-hydrocarbons up to high pressures.•This model is successfully extended to the liquid-liquid interfaces of multicomponent systems.•Simultaneous prediction of the interfacial tension, composition, and density of the liquid-liquid interfaces is possible.