A simple function for the solubility of water in dense-phase carbon dioxide

Knowledge of water solubility in dense-phase carbon dioxide is important in CCS projects. An explicit function for the solubility is determined as a function of temperature and pressure. The determination of the function is not based on thermodynamic model assumptions. Only mathematical properties of the measurement data are used in the preparation of the solubility function. The uncertainty in the measurement data has been estimated to 20-30%. The mean deviation of the found function from the measurement data in appropriate subdomains is bounded by 13%. To avoid large deflections in subdomains where measurements are missing, the function has been determined from a system of equations with low condition number.