Process design and economic optimization for the indirect synthesis of dimethyl carbonate from urea and methanol

Much attention has been paid for the synthesis of dimethyl carbonate (DMC) by urea indirect alcoholysis method, which had not been actually industrialized by now. The rigorous full process model was then necessary to optimize the process with heat integration. In this paper, a full process was designed and optimized for the DMC synthesis by urea indirect alcoholysis method based on Aspen Plus software. The technological analysis was developed to find how the process was influenced by the three main recycled materials of methanol, 1,2-propylene glycol (PG) and mixture of DMC–methanol. Simultaneously, the thermal optimization was taken into account for energy saving and the optimized process was proposed with heat integration. Moreover, the economic evaluation was implemented for the optimized process with total annualized cost (TAC) and cost of product (COP) according to the plant investment and operations. It was found that the 11.6% decrease in TAC was obtained for the optimized process compared to the original designed process. The COP analysis showed that the process was economically efficient for the production of DMC from urea and methanol.