Phase equilibrium in binary aqueous mixtures of interest in alcoholic distillation using a modified PSRK equation of state

Abstract

Phase equilibrium in binary mixtures that are found in wine and must distillation processes have been modeled using the predictive Soave-Redlich-Kwong equation, with original and modified molecular parameters. In wine and must distillation, the presence of polar substances found in the mixture to be distilled and the many components (i.e., those different from ethanol and water), called congeners, makes it difficult to model these mixtures. Thus, the prediction and correlation of the concentration of the distilled product, which is the most interesting variable, become very complex, and some experimental data are needed. The cases studied considered nine binary water + congener mixtures. The congeners considered are acetic acid, acetaldehyde, ethyl acetate, furfural, methanol, 3-methylbutanol, 2-methyl-1-propanol, 1-pentanol, and 1-propanol. These are the substances that are considered to be legal compounds by the Chilean legislation governing the production of a spirit called Pisco. The work allows evaluation of the advantages, disadvantages, and expected accuracy of this model. Comparison with available literature data is done.