Isobaric phase equilibrium of the ternary mixture ethanol + water + 2-propanol

Abstract

Simulation of the distillation of wine and must is a challenging task due to the lack of thermodynamic information because of scarcity of accurate studies of phase equilibria. Simulation of these processes is rather complicated because of the presence of polar substances (called congeners) at very low concentration. This work studies the phase behavior of the ternary system, ethanol + water + 2-propanol at 101.3 kPa being the third compound one of the most important legal congener in common alcoholic distillation. Experimental results showed that this system exhibits two binary minimum azeotropes. Prediction of activity coefficients and equilibrium compositions with different UNIFAC group contribution models showed poor accurate results. Consistency of experimental data was tested by the McDermott–Ellis method. In addition, disposable literature was compared and commented upon. The lack of experimental data in multicomponent alcoholic distillation mixtures and the low reliability of the group contribution methods suggest a prudent work into simulation of alcoholic distillation.

Keywords:

• Prediction
• Azeotrope
• Ethanol
• Water
• 2-Propanol
• Thermodynamic topological analysis

Acknowledgement

This work was supported by the CTQ2004-03346/PPQ Project (Ministerio de Educación y Ciencia, Secretaria General de Política Cinetífica y Tecnológica, España).