Predicting the Effect of Dissolved Salt on the Vapour-Liquid Equilibria for Alcohol-Water-Salt Systems

A method for the prediction of the salting effect on the vapour-liquid equilibria of ternary alcohol-water-salt systems is proposed. In the developed method, the nonidealities of the liquid phase are considered by employing Tan's modified Wilson model to describe the solvent-solvent interaction which can be obtained from the original Wilson model, and the solvent-salt interaction which can be estimated by the contribution of ion-ion and solvent-ion interactions. The parameters required by the proposed method can be gained from the solvent-solvent interaction parameters in the liquid phase activity coefficient model and the vapour pressure data of the solvent-salt system. No ternary parameter is required. The proposed method has been used to predict the VLE of 16 ternary alcohol-water-salt systems, and the predicted results agree well with the experimental data reported in the literature. The overall mean absolute deviation of bubble point temperatures is 0.804 K, and that of the vapour phase compositions is 0.0289.