Energy-saving and environmentally friendly pervaporation-distillation hybrid process for alcohol and ester recovery from wastewater containing three binary azeotropes

Abstract Herein, the development of a basic extractive distillation process for the separation of an ester/alcohol/water system, e.g., N-propyl acetate (PAC)/isopropanol (IPA)/H2O, is reported. To reduce the energy consumption of the process, mechanical vapor recompression technology was added to the basic extractive distillation process, and the heat exchange network was redesigned to further develop an enhanced distillation process. A hybrid pervaporation-distillation process was also developed to improve the high energy consumption of the solvent recovery tower used in the traditional extractive distillation process. Compared with the basic process, the total annual cost of the enhanced distillation process is 36.03% lower; thus, it is more economical. The global warming potential and acid potential of the hybrid pervaporation-distillation process are 500 kg CO2-ep and 0.75 kg SO2-ep, respectively, which indicates an improved environmental performance compared with that achieved by the traditional process. Although the economic advantage of the hybrid process compared with the enhanced distillation process is not clear when taking into account the high equipment cost, the hybrid process exhibits clear environmental performance advantages.