Experimental studies and modeling of CO₂ solubility in high temperature aqueous CaCl₂, MgCl₂, Na₂SO₄, and KCl solutions

The phase equilibria of CO 2 and aqueous electrolyte solutions are important to various chemical‐, petroleum‐, and environmental‐related technical applications. CO 2 solubility in aqueous CaCl 2 , MgCl 2 , Na 2 SO 4 , and KCl solutions at a pressure of 15 MPa, the temperatures from 323 to 423 K, and the ionic strength from 1 to 6 mol kg −1 were measured. Based on the measured experimental CO 2 solubility, the previous developed fugacity‐activity thermodynamic model for the CO 2 ‐NaCl‐H 2 O system was extended to account for the effects of different salt species on CO 2 solubility in aqueous solutions at temperatures up to 523 K, pressures up to 150 MPa, and salt concentrations up to saturation. Comparisons of different models against literature data reveal a clear improvement of the proposed PSUCO2 model in predicting CO 2 solubility in aqueous salt solutions.