A Model for Predicting Sulfur Solubility Based on Thermodynamic Model

During the development of high-sulfur-bearing natural gas reservoirs, the sulfur solubility problem needs to be studied to ensure the safe and efficient extraction of sulfur-bearing natural gas. Based on the phase equilibrium thermodynamics of high sulfur mixtures, a three-phase equilibrium thermodynamic model of gas-liquid-solid phase equilibrium was established by combining the P-R equation of state and numerical calculations of three-phase flash evaporation. The solubility of elemental sulfur in high sulfur mixtures under experimentally selected conditions is predicted. Finally, the prediction results were compared with those of the semi-empirical model and previous experimental results. It is concluded that the average relative error of the thermodynamic model for the solubility of elemental sulfur under experimental temperature and pressure conditions is less than 10%, indicating that this model can calculate the gas-liquid-solid three-phase equilibrium in high-sulfur-bearing gas reservoirs. Comparing the predicted results with results of two other models shows that the solubility values predicted by the thermodynamic model fit the experimental data better.