Theoretical pressure dependency of carbon dioxide solubility under hydrate–liquid water equilibrium

Abstract

AbstractThe effect of pressure on carbon dioxide solubility in water is significantly smaller than that of temperature under hydrate–liquid water (H–Lw) equilibrium. As a result, experimental values of carbon dioxide solubility in the water rich liquid phase under H–Lw equilibrium are often inconclusive and in some cases contradictory. This work proposes a theoretical derivation, based on fundamental thermodynamics, of the gas hydrate former solubility dependency on pressure for any binary system under two‐phase equilibrium. The obtained expression is applied to the carbon dioxide–water system under both hydrate–liquid water and vapour–liquid water equilibrium. It is shown that the solubility of carbon dioxide in the water rich liquid phase increases with increasing pressure under H–Lw equilibrium. The predicted trend is then compared to the limited experimental data available in the literature.