Direct Production of Diethyl Carbonate from Ethylene Carbonate and Ethanol by Energy-Efficient Intensification of Reaction and Separation

Abstract

This study presents a novel process for producing diethyl carbonate and ethylene glycol directly from ethylene carbonate and ethanol through reactive distillation. Previous studies have mainly focused on investigating two reactive distillation systems with a pressure swing azeotropic separation for producing diethyl carbonate. By integrating the two separated reactive distillation systems into a single flowsheet, an energy-efficient process is enabled. Especially, the need for separating the azeotrope mixture is eliminated, and the primary feed of methanol is not required due to the reaction stoichiometry. Two design alternatives have been proposed based on the reactive distillation configuration and catalyst employed. The first design significantly reduces the amount of equipment needed by utilizing two reactive distillation columns, while the second design offers high energy savings, as all reactions occur in a single reactive distillation column. Compared to the conventional process of producing individual dimethyl and diethyl carbonate, both design alternatives result in total energy consumption reductions of 12% and 24%, respectively, as well as total annual cost reductions of 12% and 14%, respectively. Furthermore, both design alternatives demonstrate a reduction in CO2 emissions by 15% and 11% respectively. Not only do these results demonstrate their economic viability, but they also indicate their effectiveness in CO2 mitigation. From an industry perspective, the two proposed design alternatives can be effectively implemented for the direct production of diethyl carbonate and mono-ethylene glycol by intensifying the existing dimethyl carbonate production process.