The Polimeri/Lummus process is a non-phosgene route using CO, CH3OH (methanol) and O2 to produce dimethyl carbonate
(DMC). DMC is a nontoxic intermediate used in the production of polycarbonates, lubricants, solvents, etc., and is also used directly as a solvent or a gasoline/diesel fuel additive. This environmentally safe process can be applied to large capacity plants.
Methanol, CO and O2 react in the presence of a copper containing catalyst to yield DMC and water (1). The main byproduct is CO2, with minor amounts of organics like dimethyl ether and methyl chloride. A small quantity of HCl is fed to the reactor to maintain catalyst activity. Unreacted gases, saturated with organics, are fed to the organics removal section (2). The clean gases, composed of CO, CO2 and inerts, are subsequently fed to the CO recovery unit (3) from where CO is recycled back to the reaction section and CO2 is sent to an OSBL CO generation unit. This CO can be sent back to the DMC process.
The reaction section effluent, containing unreacted methanol, DMC, water, and traces of catalyst and HCl, is sent to the acid recovery section (4) where catalyst and HCl are separated and recycled back to the reaction section. The remaining effluent is fed to the azeotropic distillation section (5). Methanol is recycled back to the reaction section as a methanol/DMC azeotrope, while DMC with water is fed to the final purification section (6) to obtain DMC product.
Since Lummus also offers the Polimeri/Lummus diphenyl carbonate (DPC) process, there are opportunities for energy integration as well.
Licensor: Lummus Technology