Prediction of Multiphase Equilibrium of Water-Alcohol-Hydrocarbons Using Theory-Based Equation of State

In this work, the role of long-ranged electrostatic interactions is evaluated in predicting multiphase equilibrium in water-alcohol-hydrocarbon-carbon dioxide systems using statistical association fluid theory. Various long-ranged interactions are added to the statistical association fluid theory including dipole and quadrupole interactions. The liquid-liquid and vapor-liquid-liquid behavior of complex mixtures are predicted without introducing binary interaction parameter. Three different SAFT versions are utilized; namely CK-SAFT, simplified SAFT and PC-SAFT.  The effect of the number of association sites is explored in studying various systems such as water-hydrocarbons and water-alcohols. The liquid-liquid behavior of water-hydrocarbons is quantitatively obtained without adjusting mixture experimental data.