Accurate description of gas hydrates of carbon dioxide and hydrogen for storage and transportation

This paper reports theoretical study of stability zones and composition of "H2 + CO2" clathrate hydrates of cubic structure I (sI) and II (sII) in dependence on pressure and temperature for different gas phase composition using extended van der Waals and Platteeuw statistical thermodynamic model. It was found that rising of CO2 content in H2 + CO2 gas mixture phase makes formation of sI hydrate more thermodynamically preferable rather than sII hydrate, and in the same time CO2 content increasing reduces formation pressure of the resulting hydrate. Observed difference between gas phase composition and gas molecules trapped in hydrate phase allows to consider these hydrates as a gas separation medium. We believe that presented results could be applicable for improvements of hydrate technology for CO2 utilization as a greenhouse gas, and hydrogen obtained from natural gas refinement transportation.