Novel Process for Conversion of CO₂ to Dimethyl Carbonate using Catalytic Membrane Reactors

Dimethyl carbonate (DMC) receives much attention due to its versatile use, low toxicity and fast biodegradability. Various ‘green’ production routes are explored and developed to replace the classic and rather toxic synthesis of DMC via phosgene. The direct DMC synthesis route – from CO₂ and methanol – is one of the most interesting options for the chemical industry, but this is hindered by the limited chemical equilibrium. This work describes the simulation of a novel process for DMC using PSE and PI methods. A membrane reactor plays the central role, as it continuously removes the water by-product, in order to overcome the equilibrium limitations. Aspen Plus simulations were carried out for a DMC process (20 kt/yr) and over 99 wt% purity of the DMC product. Due to the incomplete conversion in the membrane reactor, the DMC concentration in the reactor effluent is rather low hence the purification of this diluted stream leads to large recycles and requires large size equipment and a considerable amount of energy.