Simulation Of The Direct Synthesis Of DMC From Methanol And CO₂ Intensified By Reactive Distillation With Side Reactor

Dimethyl carbonate (DMC) is considered as an important chemical and gets continuous attention due to its high versatility and low toxicity. DMC can be synthesized by the direct synthesis from methanol and carbon dioxide which is believed very promising because it promotes the use of carbon dioxide and uses less toxic chemicals. But it is not considered readily feasible due to its high thermodynamic limitations. In this work, a reactive distillation with side reactor process as intensification technology was developed for the direct synthesis of DMC. The intensification mechanisms and effect of main parameters were intensively studied.The difference of relative volatility between reactants (methanol and CO2) and products (DMC and water) is obvious as the residual curve maps reveal. The temperature, pressure and composition profile in the rectifying section of distillation column approximate the best reaction conditions as generally reported in the references. As a result, the reaction conditions are easily coupled with the distillation conditions.The models of reactive distillation with side reactor were developed based on gPROMS platform. The main parameters such as pressure, feed stage and feed ratio of reactant, total stage and reflux ratio were studied in detail. The intensification mechanism of DMC synthesis was in situ water and DMC removal by reactive distillation technique, to shift the reaction equilibrium towards DMC production.Through the proposed process, the yield of DMC could increase from 10% to 99% successfully. On this basis, ethylene oxide hydration as an auxiliary reaction was introduced, and the reboiler duty decreased dramatically. The intensification mechanisation of auxiliary reaction was illustrated.