High-pressure solubility of light gases in heavy n-alkanes from a predictive equation of state: Incorporating Henry's law constant into binary interaction parameter

• An equation of state is used to calculate light gases solubility in heavy n-alkanes.
• Light gases used in this work are methane, ethane, nitrogen, carbon dioxide and hydrogen sulphide.
• Solubility of methane and carbon dioxide in water were also estimated.
• A new binary interaction parameter is introduced which combines equation-of-state pure component parameters and Henry's law constant.
• The model predicts solubility from low to very high pressure.

Using fugacity coefficient of a cubic equation of state, Henry's law constant of a solute in a solvent is incorporated into binary interaction parameter of the classical attractive parameter mixing rule. The developed equation is a function of temperature. The binary interaction parameter is evaluated by pure component critical properties and acentric factors of the solute and the solvent and the Henry's law constant of the solute in the solvent. The developed model accurately describes the solubility of gases including methane, ethane, nitrogen, carbon dioxide and hydrogen sulphide in heavy n-alkanes from low to high pressure for wide range of temperature. The solubility of methane and carbon dioxide in water is also predicted adequately.