The transesterification of propylene carbonate (PC) or ethylene carbonate (EC) to dimethyl carbonate (DMC) by using catalytic reactive distillation (RD) is a promising approach for carbon dioxide utilization. However, there is still scarcity of comprehensive comparison between the two RD processes. Hence, using the UNIQUAC model and kinetics calibrated by literature and our experiments, we conduct an extensive comparison of the two RD processes. Based on the kinetic insights, laboratory RD processes for both reactions are modeled, analyzed, and experimentally validated. Consequently, two RD processes designed to produce 60 ktpy of DMC are optimized and compared. The interplay and control factors between reaction and separation are elucidated and clarified via investigating variations of the actual chemical equilibrium constant profile compared with theoretical values along the reactive section at various pressures, liquid holdups, etc. The results reveal that the optimized EC RD process achieves almost 50 % reductions in both total annual cost and carbon dioxide emission compared to the PC RD process. This work facilitates the carbon neutrality and provides an essential guide for quantitatively assessing the two routes.@en

Distillation remains the leading and most frequently adopted technique for the separation and purification of condensable mixtures in numerous industries. However, the inherently poor thermal efficiency of distillation requires a large amount of thermal energy, making it the chief factor in total process energy usage and a significant emitter of carbon dioxide due to the combustion of fossil fuels. To address this issue, electrification has arisen as a popular approach to reduce carbon emissions in different processes by primarily replacing the energy source with electricity derived from renewable energy resources. This review is designed to thoroughly explore the electrification concept in decarbonizing distillation and present a detailed analysis and summary of the cutting-edge technologies used in various distillation operations. The focus is on creating electrified distillation processes and their associated utility systems, making use of a range of power-to-heat and intensification strategies, to achieve simultaneous carbon reduction and energy savings. With the increasing variety of operating environments that incorporate renewable power, this review additionally encompasses the control and operation aspects to ensure efficient management of electrified distillation processes. To further delve into the advantages of incorporating electrification into distillation, this work proposes future directions from the viewpoints of technological advancement, design optimization, operation, and real-time scheduling of electrified distillation processes. Furthermore, this review highlights the enormous potential of electrification in dramatically lowering carbon emissions and promoting sustainable practices in the distillation industry.@en

In industrial processes there are instances where heat pump assisted distillation falls short of full electrification, necessitating an auxiliary reboiler. To solve this limiting issue, this short communication proposes a new method using flash vapour circulation (FVC) to recuperate the waste heat within the heat pump cycle. This method incorporates a flash drum after the throttling valve to generate flash vapour. Rather than employing an auxiliary cooler for condensing the mixed vapour-liquid in a conventional heat pump system, the produced flash vapour is circulated back to the compressor inlet to enhance the recycled heat in the reboiler. With proper energy match, this approach has the potential to realise full electrification of distillation. The distillation of methanol/water serves as an illustrative case study, showcasing the viability of FVC which allows additional 22% energy savings, as compared to mechanical vapour recompression. Yet, this strategy may not be advantageous if the waste heat is already maximally utilised in preheating both the compressor and column inlet feed. The separation of tetrahydrofuran/water is used as case study to demonstrate the limitations of this approach.@en