Mutual Solubility of Water and Hydrocarbons: A New Mixing Rule and the Development of a Predictive Scheme via the Cubic Two-State Equation of State

Abstract

The cubic two-state equation of state was employed for the correlation of measured mutual solubilities of water and 68 hydrocarbons. A new Kabadi–Danner’s type mixing rule is presented, in which the water–water dispersive parameter of the cubic part is corrected due to the presence of a hydrophobic solute. The obtained binary parameters for the water–hydrocarbon pairs had a marked relationship with the chemical family (alkanes, cycloalkanes, aromatics, and unsaturated aliphatics) and with the co-volumes. This allowed the development of general correlations to predict these parameters in the case of lack of experimental solubilities. The model’s overall deviations from measured data were 12% and 16% for the solubilities of water in hydrocarbons and of hydrocarbons in water, respectively. The temperature and pressure ranges of the correlated data were 273.2 to 550 K and 1 to 1000 bar, respectively. To check model reliability, the correlations were successfully extended to predict bubble pressures and dew te...