Molecular simulation of vapour-liquid coexistence curves for hydrogen sulfide-alkane and carbon dioxide-alkane mixtures

Gibbs ensemble Monte Carlo simulations, combined with the configurational-bias technique applied to alkane chains, were performed to calculate hydrogen sulfide-alkane and carbon dioxide-alkane liquid-vapour phase equilibria for several n-alkane molecules (propane, pentane and decane). Recently proposed effective pair potentials that describe accurately the pure components coexistence curves were used in the simulations. It is shown that the use of these force fields together with the Lorentz-Berthelot mixing rules yield a description of the coexistence curves of these binary mixtures that is in good agreement with the experimental data is most cases. Some deviations from the experimental results were observed in the range of high H2S mole fraction and high pressure. Further work is needed in order to improve the level of accuracy of potential models for fluid mixtures of non polar and multipolar molecules.