Abstract

A comparative study of thermodynamic models for the correlation and prediction of vapor-liquid equilibrium data in complex systems usually found in wine distillation processes, is presented. The mixtures considered in the study include ethanol and water as major components and several other compounds at very low concentrations (ppm). These compounds are called congeners (n-propanol, methyl acetate, furfural, ethyl acetate, n-butanol, i-butanol, acetaldehyde). The models studied are UNIFAC, UNIQUAC, WILSON and NRTL. Also an equation of state of the Soave type, which includes the UNIFAC Excess Gibbs free in the mixing rules, has been analyzed. Special attention is given to the effect of the absence of parameters for any of the congener compounds, in predicting the concentration of the different components in the distillate. The results are compared with literature data and conclusions on the goodness of the different models are drawn, recommending the most appropriate method for these situations.