Solubility of CO2 in water and NaCl solution in equilibrium with hydrate. Part I: Experimental measurement

• We obtained the formation conditions of CO2 hydrate in water and NaCl solution.
• Solubility of CO2 in water in equilibrium with hydrate was determined.
• We measured the solubility of CO2 in NaCl solution in equilibrium with hydrate.
• We investigated the influences of experimental conditions on the solubility of CO2.

In this work, the formation conditions of CO2 hydrate in different solutions were measured and calculated by the Chen–Guo hydrate model. Then, the solubility of CO2 in water in equilibrium with hydrate were determined and compared with reference data. The good agreement between the experimental and reference values demonstrates the reliability of the apparatus and method in this work. Finally, we measured the solubility of CO2 in 1.0 wt%, 3.0 wt% and 3.6 wt% NaCl solutions in equilibrium with hydrate under near temperature and pressure conditions of seabed. The influences of temperature, pressure and NaCl concentration on the solubility of CO2 were also investigated. The results show that the solubility of CO2 in NaCl solution is less than that in water. It increases with the temperature, and decreases with the pressure and concentration of NaCl.