Design and optimization of etherification reaction-assisted separation process for dimethyl carbonate/methanol azeotrope system

Abstract

Dimethyl carbonate (DMC) has high commercial value as an important raw material for diesel. Aiming at the industry problem of high energy consumption in DMC/methanol (MeOH) azeotrope separation, a new idea of MeOH/DMC azeotropic system with mixed C4 etherification reaction-assisted separation was proposed for the first time in this study. The process couples the transesterification segment of ethylene carbonate (EC) with the etherification segment of methyl tert-butyl ether (MTBE), which breaks the azeotropic state of MeOH and DMC by inducing the reaction of MeOH with isobutylene to produce MTBE. First, the kinetic parameters of the transesterification and etherification reactions were investigated. Then the process was designed and simulated in Aspen Plus. Finally, in order to further recover the waste heat of the reaction section, the optimal configuration of steam-driven heat pump coupled with Rankine cycle was designed. The results showed that the EC conversion reached 100 %, the purity of DMC and MTBE reached 99.99 % and 99.5 %, respectively, and the total energy consumption, environmental pollutant emission and TAC were reduced by 36.0 %, 40.0 % and 32.7 %, respectively, compared with that of the original conventional process.