Phase Equilibrium Modeling for Carbon Dioxide Solubility in Aqueous Sodium Chloride Solutions Using an Association Equation of State

Abstract

The model, i.e., the thermodynamic model, focused on the cubic-plus-association equation of state combined with the Wong–Sandler mixing rule with six parameters is presented (CPA-WS). The model confirmed that the inert association scheme is more suitable for carbon dioxide (CO2) than the 3B association scheme, for the level equilibrium in the carbon dioxide–water (H2O) system. Meanwhile, the CO2–H2O–sodium chloride (NaCl) system can be reasonably well predicted by using two adjustable parameters of the H2O–NaCl and CO2–NaCl systems. The average absolute relative deviations of the predicted CO2 solubility in H2O and aqueous NaCl solutions of the CPA-WS model are 5.31 and 3.56%, respectively.