Optimal separation of acetonitrile and pyridine from industrial wastewater

A mixture of water, pyridine and acetonitrile is obtained as a by-product during the pharmaceutical industry. Azeotropic-extractive distillation (AED) and azeotropic-pressure swing distillation (APSD) are used to separate this mixture. In this work, we perform an optimization study of the total energy consumption of both processes by using a single factor analysis and response surface methodology (RSM). Compared to single factor optimization, the results showed that the energy saving optimized by RSM of AED and APSD was 37.27% and 27.36% respectively. The heat exchange network is optimized according to ASPEN ENERGY ANALYSIS. The results showed that the energy saving of AED and APSD after heat transfer optimization was 12.3% and 33%, respectively. By comparing the energy consumption of the two processes, it was found that the optimized AED process had an energy saving of about 1.05% compared with APSD. However, since there is no extractant entrainment in the APSD process, the APSD process is finally selected. ? 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

In this study, the total energy consumption of AED and APSD processes was optimized using single factor analysis and response surface methodology (RSM). The results showed significant energy saving achieved through RSM optimization, as well as positive impact of heat exchange network optimization. The APSD process was ultimately selected after comparing the energy consumption of the two processes.