Solubility of Methane and Carbon Dioxide in the Aqueous Phase of the Ternary (Methane + Carbon Dioxide + Water) Mixture: Experimental Measurements and Molecular Dynamics Simulations

Abstract

New experimental measurements (at 10 MPa and 323.15 K) and molecular dynamics (MD) simulations (at 10 MPa and 323.15 K, 50 MPa and 344.25 K, and 50 MPa and 375.5 K) are reported in order to measure/predict the aqueous solubilities of the ternary methane–carbon dioxide–water system under two-phase (vapor–liquid) equilibrium conditions. The TIP4P/ice, TraPPE-UA, and OPLS-UA force fields for water, carbon dioxide, and methane, respectively, are used, according to the modifications introduced in the recent study by Michalis et al. (Phys. Chem. Chem. Phys., 2016, 18, 23538–23548) for the binary methane–carbon dioxide hydrate. The MD calculated values for the solubility are in good agreement with the newly available experimental measurements. The molecular dynamics simulations clearly indicate that the solubility of each gas decreases by the addition of the other gas. The particular conclusion is in excellent agreement with the conclusion obtained from the new experimental measurements reported in the current s...