Monte Carlo predictions for the phase behavior of H2 S+n-alkane, H2 S+CO2, CO2+CH4 and H2 S+CO2+CH4 mixtures

Phase diagrams for binary mixtures of H2 S+n-alkanes, H2 S+CO2, CO2+CH4 and a ternary mixture containing H2 S, CH4 and CO2 are determined with atomistic simulations. Pressure–composition diagrams for each of the binary mixtures are determined with configurational-bias Monte Carlo simulations in the grand canonical ensemble, combined with histogram-reweighting techniques. Overall, the predicted phase diagrams for the H2 S+n-alkanes and CO2+CH4 mixtures are found to be in excellent agreement with experiment, while significant deviations are found between simulation and experiment for the H2 S+CO2 mixture. Gibbs ensemble Monte Carlo simulations are used to determine the ternary phase diagram for the H2 S+CH4+CO2 mixture at 310.93 K and 41.3 bar. Comparison of simulation to experiment shows a close agreement at the temperature and pressure studied in this work.