Vapor–Liquid Equilibrium of Water + Ethanol + Glycerol: Experimental Measurement and Modeling for Ethanol Dehydration by Extractive Distillation

Abstract

The present work aims at establishing reliable activity coefficient model for vapor–liquid equilibrium (VLE) of the system water + ethanol + glycerol, with an emphasis on the application in ethanol dehydration by extractive distillation. New experimental data were reported for ternary VLE at 100 kPa, boiling temperature of water + glycerol at 101.33 kPa, and infinite dilution activity coefficient of water and ethanol, respectively, in glycerol at five temperatures of 313.15 K to 393.15 K. The NRTL equation was used for the modeling. For extending the composition and temperature range of data source, literature data of binary VLE of water + ethanol, infinite dilution activity coefficients of water + ethanol, and excess enthalpies of water + glycerol were also used for optimization of the NRTL parameters. The correlation showed that the azeotrope of water + ethanol can be removed at a glycerol mass fraction of 0.0902. The experimental results were compared graphically with those of calculations, showing good agreement. Comparisons were also presented for experimental results and correlations available in the literature.