GROUP-CONTRIBUTION VISCOSITY PREDICTIONS OF LIQUID-MIXTURES USING UNIFAC-VLE PARAMETERS

A group-contribution model for both viscosity and activity coefficients prediction for liquid mixtures is proposed. A group-contribution viscosity equation and a group-contribution activity coefficient equation are obtained from the model and expressed by the same group parameters. The group interaction parameters can be determined from viscosity data, activity coefficient data, or both. The group-contribution activity coefficient equation is exactly that of UNIFAC, and for group interaction parameters we use directly the already available UNIFAC-VLE parameters (i.e., interaction parameters are determined from experimental vapor-liquid equilibrium (VLE) data). The viscosity predictions for liquid mixtures can thus be carried out without any viscosity information of liquid mixtures. The viscosity prediction results have been compared with experimental data, and the average deviation between these is generally within 5 %.