Comprehensive evaluation and comparison of advanced separation methods on the separation of ethyl acetate-ethanol-water highly non-ideal mixture

Abstract

Ethyl acetate and ethanol are important organic solvents in fine chemical industry, which form with water ternary minimum-boiling azeotrope and three binary azeotropes, including heterogeneous-azeotrope. In this article, different distillations and pervaporation methods are studied to separate sharply the ternary mixture. In the case of separation of highly non-ideal mixtures the distillation based separation methods can be extraordinarily complex. The extractive heterogeneous-azeotropic distillation (EHAD) as new improvement can be a promising tool for splitting the ternary mixture. This process contains the preferences of heterogeneous-azeotropic- and extractive distillations in one unit without extra material addition.Four advanced separation methods are compared: Method I (pressure swing distillation (PSD) for ethyl acetate purification with extractive distillation (ED) for ethanol purification), Method II (PSD with distillation-hydrophilic pervaporation (D + HPV) for ethanol purification), Method III (EHAD + PSD with ED) and Method IV (EHAD + PSD with D + HPV).The different alternatives are rigorously modelled in ChemCAD simulator and optimized with the dynamic programming optimization method first in the literature. In the case of distillation operations, heat integration is also considered, the feed is preheated with its bottom stream. Such ternary pervaporation separation with new semi-empirical model has not been published in this professional flowsheet environment yet. The distillation and pervaporation models are experimentally verified. Separation factor values are compared to those of other published membranes in the recent literature and it is found that PERVAP™ 1510 has the highest separation factor value.It can be determined that every method is capable for the separation of ethyl acetate-ethanol-water ternary mixture. The methods are optimized by economic evaluation based on the total annual cost (TAC) and the EHAD + PSD with D + HPV is found the optimum, because it has the lowest heat duties.