Economic, environmental, exergy (3E) analysis and multi-objective genetic algorithm optimization of efficient and energy-saving separation of diethoxymethane/toluene/ethanol by extractive distillation with mixed extractants

Abstract

Diethoxymethane, toluene, ethanol are important organic solvents with excellent performance and are widely used in the industrial fields. In this study, extractive distillation with mixed extractants was used to separate the mixture. The separation process of diethoxymethane, toluene and ethanol azeotrope system with different extractant agents was designed. The multi-objective optimization was carried out with the objective of total annual cost and gas emission, and the optimal process parameters were obtained by coordinating the two objectives. Based on the best extractive distillation process with mixed extractants, the intensification of process was performed by adding heat pump and heat integration technology, to improve the economy and energy consumption of the process. By comparing the results of economic, environmental and exergy efficiency analysis calculations, it was found that the intensification of the heat integration technology was better than the intensification of the heat pump. As for the intensification effect of heat integration technology saved about 5.5% more economical than primary mixed extractants process, the gas emission had been reduced by about 14.8% in terms of environment, and exergy loss decreased by 33.8%. This study provides theoretical guidance for the design and optimization of extractive distillation processes using the mixed extractants.