Phase Equilibria Containing Gas Hydrate of Carbon Dioxide, Sulfur Dioxide, and Water Mixtures

Three- and four-phase hydrate equilibria for mixtures composed of carbon dioxide, sulfur dioxide and water were measured at pressures up to 5.00 MPa. Using Duhem's theorem on phase equilibrium, incipient hydrate-forming temperatures at given pressures with overall loading compositions of all components were measured, using an indirect visual phase equilibrium apparatus. In this study, effects of the relative amount of water to fixed composition of carbon dioxide and sulfur dioxide gas feed were studied. Phase equilibria were found to be sensitive to the water fraction at higher concentrations of sulfur dioxide in the gas feed but insensitive at lower concentrations. Four-phase equilibrium measurements showed the pseudoretrograde hydrate behavior.