Eco-efficiency analysis and intensification of the acetic acid purification process

This work presents three intensification strategies for an acetic acid purification process. The proposed configurations employing double-effect distillation and vapor recompression were designed by computer simulation in UniSim Design Suite. The simulation of a utility plant was also carried for more accurate estimations of water and energy consumption, capital expenditures and production costs. The intensified technologies are compared to the original process and to a thermally coupled technology using the Eco-efficiency Comparison Index method based on five environmental indicators (namely carbon dioxide emissions, water consumption, terrestrial toxicity potential, aquatic toxicity potential and acidification potential), one safety indicator (namely human toxicity potential by exposure) and four economic indicators (namely capital expenditures, specific energy costs, specific water costs and liquid waste cost fraction). The results showed that the intensification strategies were from 28.9-67 % more eco-efficient than the original process. The vapor recompression design resulted in the best sustainability performance, mainly due to an 80.5 % lower energy consumption, which provided a 67% increase in its eco-efficiency compared to the original technology and approximately 44 % compared to one of the double-effect distillation strategies and the thermally coupled design, which comprised the second and third best alternatives, respectively.