Dimethyl carbonate (DMC) is a green compound with a wide range of applications. Recently, CO2-based DMC production routes have attracted much attention due to the environmental benefits of CO2 utilization. In this study, we investigated a plant-wide process design for the production of DMC from CO2 via indirect alcoholysis dimethyl carbonate of urea. The indirect alcoholysis of urea has the advantages of cheap raw materials, mild and safe operating conditions, and environmentally friendly chemicals. DMC production includes urea synthesis, propylene carbonate (PC) synthesis, DMC synthesis, DMC/methanol azeotrope separation and other processes. Methods such as urea synthesis, DMC synthesis, and DMC/methanol azeotrope separation have been well developed. In the study, the focus was on the PC synthesis process. Several different PC synthesis methods were proposed, designed, and optimized. Simulation results show that an intensified process comprising a reactive distillation column and a conventional distillation column with internal vapor compression takes full advantage of the special azeotropic properties of the propylene carbonate and propylene glycol pair to provide the most economical design. Compared with the traditional process, the enhanced process can reduce the total annual cost by 21.8%. In addition, a plant-wide process for DMC production was designed. The net profit of the production process is also given.
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Dimethyl carbonate (DMC) is of increasing importance in the chemical industry. DMC is an environmentally friendly and biodegradable chemical that has attracted a lot of research efforts in recent years. DMC can be synthesized from cyclic carbonate compounds such as ethylene carbonate or propylene carbonate. In this reaction, a cyclic carbonate is transesterified with methanol to form DMC and the corresponding ethylene glycol. There have been some reports on the synthesis of DMC from ethylene carbonate and methanol [1-7]. In these studies, alkali metals [1], free organophosphines supported on partially crosslinked polystyrene [2], as well as zeolites [3,6], alkali metal oxides [4,5] and hydrotalcites [7] and other heterogeneous catalysts are used as catalysts for the reaction. However, for some of these catalysts, the activity or selectivity is not that high.