Intensification of an extractive distillation process for 2-Methoxyethanol/Toluene separation via double vapor recompression strategy

Abstract

Toluene and 2-methoxyethanol are commonly generated as waste in the production of paints, varnishes, and in the electrochemical industry. These compounds form an azeotropic mixture, requiring separation through specific processes that are energy-intensive like pressure swing and extractive distillation. Thus, intensification strategies were designed to reduce energy consumption, utility costs, and pollutant emissions. An extractive dividing-wall distillation (EDWC) scheme was previously proposed to intensify the said separation process. As a novel contribution, this work proposes another strategy based on double vapor recompression (DVR). Total annualized cost (TAC) and CO₂ emissions were considered as economic and environmental performance evaluation metrics, respectively. The direct comparison between the EDWC and DVR intensification configurations showed that for a 5-year payback period, both presented equivalent economic performance. However, over a 10-year payback period, the DVR scheme presented savings of 56.80% and 17.67% in CO₂ emissions and TAC, respectively, outperforming its EDWC counterpart. Additionally, the new proposal reaches the break-even point in just 3 years and 4 months when compared to the conventional setup. These results position DVR as a more sustainable and cost-effective solution for retrofitting operating plants globally, aligning with the United Nations Sustainable Development Goals by significantly improving both environmental and economic performance.