High Pressure Solubility of Light Gases (CH₄, C₂H₆, C₃H₈, H₂S, CO₂, N₂, Xe, Ar and Kr) and Certain Gas Mixtures in Water from Cubic Equations of State

Using Henry’s law constant, we applied a previously developed approach to the Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK) equations of state in deriving formulas for the binary interaction parameters of van der Waals mixing rules. The formulas are solely temperature dependent and require the Henry’s law constant of a gas in water in addition to the critical temperatures, critical pressures and acentric factors of the gas and water. The method was successfully used to predict the solubility of methane, ethane, propane, hydrogen sulfide, carbon dioxide, argon, krypton, xenon and nitrogen in water for wide ranges of temperature and pressure. Among the equations of state, PR was found to have the best performance with average absolute deviation of 5.2%. In addition, PR was employed to predict the solubility of gas mixtures in water, including methane + ethane, methane + n-butane and methane + ethane + n-butane at pressures up to 100 MPa. The accuracy of predictions was found to be comparable to those of the solubilities of pure gases in water.