Eco‐efficiency improvements in the propylene‐to‐epichlorohydrin process

Abstract

BACKGROUND Epichlorohydrin (ECH) production is an important industrial process, owing to its importance in windmill blade manufacture, but it suffers from several drawbacks such as high energy use, large wastewater production and low atom efficiency. This original study investigates a novel chlorohydrin‐free technology with an enhanced separation system for ECH production. Rigorous process simulations were performed in Aspen Plus for the classic and novel processes, and a fair techno‐economic and sustainability comparison was made between the new catalytic oxidation route and the classic chlorohydrin process. RESULTS For the hydrogen peroxide (HP) process route, a novel separation system was developed using methanol as solvent, which enables high purity of ECH. Moreover, allyl chloride (ACH) purification was optimized using thermally coupled distillation to improve the energy efficiency of ACH production. The novel HP process provides 88% higher atom efficiency, about 10% higher yield and a smaller amount of by‐products, as well as a 13% increase in production capacity and major savings of 98% in wastewater production, while also achieving lower energy use (<40 MJ kg−1 ECH) and reduced carbon dioxide emission (1.13 kg kg−1 ECH). CONCLUSION The developed HP process route is feasible and economically viable. Also, it can be partly retrofitted to existing ECH plants based on the chlorohydrin route. As both processes use the same intermediate product, only the ECH part of a classic process would be replaced by the novel route, while keeping the common ACH part. This approach is the most profitable, as only 55% of capital expenditure is required for this modification, while the plant would benefit from all the improvements provided by the novel process. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Evaluation and control of energy‐efficient processes for separating epichlorohydrin‐oriented quaternary system

“…In this study, Aspen Plus V12 is utilized for process simulation, and the NRTL thermodynamic model is employed to describe the phase equilibrium behavior of the ECH/H 2 O/ALC/MET system. The NRTL model has been used to predict the vapor–liquid and liquid–liquid phase equilibrium of quaternary systems in previous literature, 21,22,26 and the simulation results agree well with the experimental results. The binary interaction parameters of the NRTL model are referenced from the summary of Yang et al 22 .…”

“…applied a three‐column/decanter process to recover valuable benzene and isopropanol from wastewater, and further energy‐saving schemes of this separation system were also thoroughly investigated. Madej and Kiss 26 considered the column/decanter approach to separate reaction products in a study of direct epoxidation of ALC to produce ECH, with liquid–liquid phase separation showing promising results in purifying ECH.…”

Technological Insights on Glycerol Valorization into Propanediol through Thermocatalytic and Synthetic Biology Approaches

“…1,2-propanediol is conventionally synthesized through the hydrolysis of propylene oxide, a chemical that is generated by the processing of crude oil [74,75]. There are multiple approaches to producing propylene oxide, but one regularly used method is the chlorohydrin route, which produces a large amount of calcium chloride waste [74,76]. New production facilities do not utilize this method as modern alternatives can greatly reduce the amount of waste produced when synthesizing propylene oxide.…”