A Modified van der Waals Mixture Theory for Associating Fluids: Application to Ternary Aqueous Mixtures

In this study a simple and general chemical association theory is introduced. The concept of infinite equilibrium model is re-examined and true mole fractions of associated species are calculated. The theory is applied to derive the distribution function of associated species. As a severe test the application of presented theory to the van der Waals mixture modelis introduced in order to perform Vapor-Liquid Equilibrium (VLE) calculations of aqueous ternary mixtures. The calculations are shown to be consistently improving the prediction over the non-associating case. Also, well known empirical models of NRTL and UNIQUAC are applied on the studied systems and their results are compared with proposed model.