Solubility of CO2 in aqueous solutions of NaCl, KCl, CaCl2 and their mixed salts at different temperatures and pressures

Abstract

The solubility of CO2 in water and aqueous solutions of NaCl, KCl, CaCl2, NaCl+KCl (weight ratio=1:1), NaCl+CaCl2 (weight ratio=1:1), KCl+CaCl2 (weight ratio=1:1), and NaCl+KCl+CaCl2 (weight ratio=1:1:1) was determined at 35.0, 45.0 and 55.0°C up to 16MPa, and the concentration of the salt was up to 14.3wt%. It was demonstrated that solubility increased with increase in pressure, and decreased with increasing temperature. Addition of a salt or salt mixture resulted in reduction in the solubility due to the salting-out effect. At the same salt concentration (wt%), the salting-out effect of KCl was considerably smaller than those of NaCl and CaCl2. The salting-out effect of a salt mixture is between those of its components.