Isobaric vapor-liquid and vapor-liquid-liquid equilibrium for the system water + ethanol + n-heptane

Abstract

Heterogeneous azeotropic distillation is a widely used technique to separate binary azeotropic mixtures into their components. One of its most important applications is the dehydration of ethanol, which is blended with gasoline to obtain automobile fuel. Among all the compounds that could be used as an entrainer, heptane was chosen because it is one of the common components of gasoline. The advantage of this entrainer is that the remaining quantity of heptane in the ethanol will not be a problem for its subsequent use as a fuel. Obviously, to carry out that research, knowledge of the vapor-liquid (VLE) and the isobaric vapor-liquid-liquid equilibrium (VLLE) data is required. In this study, VLE and VLLE were measured for the ternary system water + ethanol + n-heptane at 101.3 kPa. The experimental data were correlated using NRTL and UNIQUAC and predicted with UNIFAC.