Development of predictive methods of water-heavy oil phase equilibrium for supercritical water upgrading process

Abstract

Predictive methodology was developed for water-hydrocarbon systems under high temperature and pressure conditions based on reported phase equilibrium data using the Peng-Robinson equation of state (EOS) for vaporliquid equilibrium (VLE) and liquid-liquid equilibrium (LLE). The available experimental data for hydrocarbons with low molecular weight and interaction parameter, kij, with/without a size parameter, lij, included in the Peng-Robinson EOS were fitted to experimental data and accumulated for constructing a predictive equation for hydrocarbons with high molecular weight. As a result, lij was found to be negligible for VLE in water-hydrocarbon systems, and only the fitting parameter kij was necessary in some hydrocarbon and water systems. Consequently, prediction of VLE diagrams was possible using the estimated kij in the Peng-Robinson EOS for water-hydrocarbon systems under high temperature and pressure conditions.