Study on a New Reactive Dividing-Wall Column for the Reaction of Vinyl Carbonate and Methanol Ester Exchange to Produce Dimethyl Carbonate

Abstract

Dimethyl carbonate (DMC) is a promising green chemical that plays a significant role in the sustainable chemical industry, clean energy technologies, and environmental protection. In response to the challenges of high equipment investment and energy consumption in the existing process for producing dimethyl carbonate through an ester exchange reaction using vinyl carbonate and methanol, a new reactive dividing-wall column (RDWC) process was developed. A new RDWC model was established by using Aspen Plus. The impact factors of reaction conditions such as reactant molar ratio, theoretical number of reaction stages, reaction pressure, and separation conditions such as theoretical number of common rectifying section, theoretical number of common stripping section, liquid phase distribution on both sides of the dividing wall, and side draw location were analyzed. A laboratory-scale new RDWC was designed and built referenced to the simulation results. The experimental research investigated key parameters affecting the reaction distillation column, such as the reaction zone height, reactant molar ratio, liquid phase distribution, reflux ratio, and vapor phase distribution on both sides of the dividing wall. This research laid the foundation for the scale-up designing of process parameters for the new RDWC. Under optimized conditions, the conversion rate of reactant EC (ethylene carbonate) exceeded 99.9%, the purity of methanol in the side draw was at least 99 wt %, and the purity of methanol ethylene glycol in the distillation column achieved a concentration greater than 99% (excluding the catalyst). The new method can greatly shorten the transesterification process (integrate the three towers in the original process into one) to produce dimethyl carbonate, save investment, and reduce energy consumption.