Economy, environmental assessment and energy conservation for separation of isopropanol/diisopropyl ether/water multi-azeotropes via extractive distillation coupled pervaporation process

This wok proposed the extraction distillation coupled pervaporation (ED+PV) technology process using two different solvents to separate isopropanol (IPA) and diisopropyl ether (DIPE) from DIPE/IPA/H2O tern-ary heterogeneous azeotropes in industrial wastewater from the synthesis of isopropanol in this study. Based on strict design specifications, simulation and sequential iteration methods are used for process design and optimization. Compared to the ethylene glycol (EG)-EG+H2O process and the 1,3-propanediol (PDO)-IPA+H2O process, the total annual cost (TAC) of the EG-IPA+H2O process decreased by 20.76% and 7.86% (PDO). Compared to the EG-EG+H2O process, the TAC of the PDO-IPA+H2O process reduced 14%, but the global warming potential (GWP) and human toxicity of the PDO-IPA+H2O process increased 11.3% and 4.07% respectively. Compared to the PDO-IPA+H2O process, the EG-IPA+H2O process saves 7.86% (TAC), 9.78% (GWP) and 9.85% (human toxicity). The ED+PV process with EG is superior to PDO in factors of TAC, energy consumption, human toxicity and environment. The EG-IPA+H2O process changed the separation order of the products of the multi-azeotropic system, reduced the cost and energy conservation of the system, and enhanced the environmental protection evaluation of the process, is the best process through life cycle assessment for analyzing the economy, energy conservation, environmen-tal assessment and human toxicity, designing cleaner products, controlling waste discharge, and promot-ing the chemical purification industry. This work provides a new process design and optimized separation ideas, will have a good guiding significance for the research and application separation of multi-azeotropic mixture with mixed solvents in organic wastewater from the cleaner chemical produc-tion, has been up to standard wastewater discharge process, and realized the development goal of carbon peak and carbon neutrality in the sustainable development of chemical clean industry. (c) 2022 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.