Prediction of Equilibrium Interfacial Tension between CO2 and Water Based on Mutual Solubility

In this paper, an interfacial tension (IFT) correlation (i.e., Model #2) between CO2 and water is generalized as a function of their mutual solubility and the reduced pressure of CO2 in a temperature range of 278.2–469.2 K and a pressure range of 0.10–69.10 MPa. Two sets of correlation coefficients are respectively regressed for pressures lower and higher than the critical pressure of CO2 (i.e., 7.38 MPa). Such a newly developed correlation is calculated to yield an absolute average relative deviation (AARD) of 4.5%, a maximum absolute relative deviation (MARD) of 32.3%, and a maximum absolute deviation (MAD) of 1.65 mN/m, respectively. The newly developed model is found to greatly outperform the four existing correlations as a function of temperature, pressure, or CO2 solubility in water. A higher CO2 solubility in water (i.e., xCO2) leads to a lower IFT for all pressures, while a higher water solubility in the CO2 phase (i.e., yW) results in a lower IFT mainly at lower pressures. Both pressure and tempe...