Modeling interfacial tension of (CH4+N2)+H2O and (N2+CO2)+H2O systems using linear gradient theory

Abstract

The linear gradient theory (LGT) of fluid interfaces in combination with the cubic-plus-association equation of state (CPA EOS) is applied to determine the interfacial tensions of (CH4+N2)+H2O and (N2+CO2)+H2O ternary mixtures from 298–373 K and 10–300 bar. First, the pure component influence parameters of CH4, N2, CO2 and H2O are obtained. Then, temperature-dependent expressions of binary interaction coefficient for (CH4+H2O), (N2+H2O) and (CO2+H2O) are correlated. These empirical correlations of pure component influence parameters and binary interaction coefficients are applied for ternary mixtures. For (CH4+N2)+H2O and (N2+CO2)+H2O mixtures, the predictions show good agreement with experimental data (overall AAD∼1.31%).