Mechanism Analysis, Economic Optimization, and Environmental Assessment of Hybrid Extractive Distillation-Pervaporation Processes for Dehydration of n-Propanol

n-Propanol, as an important chemical raw material, is used as a solvent and intermediate in chemical industrial production and drug synthesis. In chemical production, alcohol and water easily form an azeotrope which is difficult to separate. In this work, a method of dehydration of n-propanol by pervaporation-assisted extractive distillation is proposed. Glycerol is selected as entrainer by quantum chemical calculation. A combined pervaporation unit with cellophane as a membrane is designed to separate the entrainer and water. The pervaporation unit is developed by using the Aspen Custom Modeler. Based on the minimum total annual cost, the extractive distillation process, feed-preheating extractive distillation process, and pervaporation-assisted extractive distillation process are optimized. The results show that the total annual cost of pervaporation-assisted extractive distillation is minimum and can reduce the total annual cost by 21.25%, compared with extractive distillation. Life cycle analysis is used to evaluate the environmental impact of processes. The results of environmental performance evaluation show that the pervaporation-assisted extractive distillation has the least environmental impact. Thus, the integration technology of membrane and distillation is of great significance in the sustainable process of chemical design and development.