CO2 Solubility in Aqueous Solution in a Hydrate–Liquid Two-Phase Equilibrium System

In marine environments, natural gas hydrates can be surrounded by seawater, forming a hydrate–liquid (H–L_w) two-phase system. This work developed a new experimental method to prepare an H–L_w two-phase equilibrium system and then measured the gas solubility in the corresponding liquid phase. The experimental temperature range is 274.25–282.25 K, and the experimental pressure range is 1.407–7.184 MPa. Ninety-two experimental data points of CO₂ solubility in the H–L_w two-phase equilibrium system are reported in this work. The experimental results indicate that the CO₂ solubility in the liquid phase is almost unaffected by the liquid-phase pressure, while it significantly increases with the increase in system temperature in the H–L_w two-phase equilibrium system. The effect of NaCl concentration on the CO₂ solubility in the H–L_w two-phase equilibrium system is complex and also related to the system temperature.