SIMULAÇÃO DA DESTILAÇÃO EXTRATIVA PARA PRODUÇÃO DE ETANOL ANIDRO: INFLUÊNCIA DO TEOR DO LÍQUIDO IÔNICO [EMIM][BF₄] EM MISTURA COM ETILENOGLICOL SOBRE O DESEMPENHO ENERGÉTICO DO PROCESSO

Abstract

Anhydrous ethanol is a strategic product for the energy and chemical sectors, but obtaining it in high purity is hampered by the presence of the ethanol-water azeotrope, which makes separation by conventional distillation impossible. Among the alternatives employed, extractive distillation stands out, particularly due to the use of solvents that modify the vaporliquid equilibrium. In this context, ionic liquids have been studied as more sustainable replacements for traditional solvents, such as ethylene glycol (EG). This work aimed to simulate and evaluate the extractive distillation of the ethanol-water system using ethylene glycol (EG) and the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF₄]) as solvents. To this end, a flowchart representing the industrial process was developed in Aspen Plus, adopting the NRTL thermodynamic model to calculate vapor-liquid equilibrium. Different proportions of [EMIM][BF₄] and EG were analyzed, evaluating their influence on anhydrous ethanol purity, reboiler and condenser thermal loads, and specific energy consumption (SEC). The results showed that ethanol purity at the top of the column remained in the range of 0.995 up to approximately 40% [EMIM][BF₄], a condition considered optimal. In this range, a maximum reduction in the total reboiler load to approximately 63.2 kW and a lower SEC value of 0.682 kWh/kg were observed, indicating significant energy gains compared to cases with a lower amount of ionic liquid. At higher concentrations, above 50% IL, a purity reduction specification (decrease to ≈0.994) and an increase in overall energy consumption were observed, compromising the process viability. It is concluded that the combined use of EG and [EMIM][BF₄] can improve the energy efficiency of extractive distillation, with the 40% IL and 60% EG scenario being the most promising, as it combines lower energy consumption with maintained product quality. The study also highlights the potential of ionic liquids as alternative entrainers, although additional economic and environmental analyses are needed for industrialscale validation.