Methane solubility in aqueous solutions under two-phase (H–Lw) hydrate equilibrium conditions

We report a detailed review of thermodynamic models and experimental data of gas solubilities in aqueous solutions, under hydrate formation conditions. In the current study we are mainly interested in describing the methane solubility in water under two-phase (Hydrate–Liquid water) equilibria, while we also briefly examine the case of methane solubility in water under three-phase (Hydrate–Liquid–Vapor) equilibria. To this purpose we use different computational models that couple: (i) an Equation of State for fugacity calculations, (ii) the van der Waals–Platteeuw theory from Statistical Thermodynamics for hydrate equilibrium calculations, and (iii) models that calculate the methane solubility in aqueous solutions. The methane–solubility results that are predicted by the examined models are compared against all available experimental data from the literature. Good agreement is observed between predictions and experimental data, considering that the methane solubility in water is very low under the pressure and temperature conditions that were examined in this study.