Integrated process development and performance evaluation based on reactive extractive distillation for sustainable recovery of useful components in refinery wastewater

This study proposes an integrated process based on mechanical vapour recompression technology, pervaporation technology, and reactive extractive distillation to treat triethylamine and hydrogen sulfide in refinery wastewater. Through methods such as relative volatility analysis, molecular mechanism research, and quantum chemical calculations, ethylene glycol was selected as the optimal extracting agent, effectively overcoming the separation bottleneck of the triethylamine-water azeotrope. Accordingly, a clean production process for the direct production of hydrogen sulfide via extraction distillation was designed, along with a process that combines mechanical vapour recompression technology with reactive extractive distillation, with parameters optimized through a sequential iterative method. To effectively utilise the waste heat generated in the process and improve environmental sustainability, heat exchange technology and pervaporation technology were introduced. The comprehensive analysis of 3E shows that the total annual cost of the combined process of pervaporation and extractive distillation is 8.15 % lower than that of the traditional extractive distillation process, the energy consumption is reduced by 22.97 %, and the gas emission is reduced by 23.43 %. The mechanical vapour recompression-pervaporation-reactive extractive distillation process further reduced gas emissions by 4.26 % compared to the pervaporation-extraction distillation process, while generating an additional 1.4166×108 $ in annual revenue from the production of high-value-added sodium sulphide by-products. The results show that the mechanical vapour recompression-pervaporation-reactive extractive distillation process is efficient, economical, and environmentally friendly. It not only achieves essentially complete conversion of hydrogen sulfide, but also provides an innovative and cleaner production solution for refinery wastewater treatment and resource recycling.