Abstract

RIOS, LUIS  and  MARIN, JUAN. PHASE EQUILIBRIUM FOR ETHANOL-WATER SYSTEMS IN THE PRESENCE OF SALTS AND POLYALCOHOLS. Dyna rev.fac.nac.minas [online]. 2011, vol.78, n.165, pp.150-159. ISSN 0012-7353.

A semi-empirical thermodynamical model was proposed for the liquid-vapor equilibrium of ethanol-water systems in the presence of salts and polyalcohols. The model uses the Gibbs-Duhem and Debye-Hückel equations, which modify the UNIQUAC-E model. Strong chemical interactions, associated with hydration and solvation phenomena of ions, as well as the Ohe model were considered. Short-range interactions, like van der Waals forces, and long-range interactions involved in the Debye-Hückel equation were also considered. Empirical parameters were obtained for ethanol-water-polyalcohol-calcium chloride and potassium acetate systems, these systems are important in industrial applications because the addition of polyalcohol and salt improves the efficiency of the separation. Measurements of the isobaric vapor-liquid equilibrium were performed in an Othmer distiller. This thermodynamic model could be useful to design and simulate the extractive distillation water-ethanol.

Keywords : Liquid-vapor equilibrium, polyalcohols,; salt-effect; ethanol-water system.

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