Bharat Lajjaram Bhatt

Novel technology for the synthesis of dimethyl ether from syngas

Abstract A novel process for producing dimethyl ether (DME) from synthesis gas in a single-step reaction sequence has been developed. The new process uses a slurry reactor in which methanol synthesis, methanol dehydration to DME, and water-gas shift reactions all proceed concurrently. All three reactions are exothermic and reversible. Operation with a back-mixed slurry reactor exploits synergisms of the three reactions, and moderates the reaction exotherm to permit higher conversion of the syngas to liquid products than could be achieved from the three reactions practiced separately. The process offers potential lower capital and operating costs than processes using individual shift, methanol, and DME reaction stages. Process development to-date has focused on the use of coal-derived synthesis gas that is rich in CO. Catalysts used in the process can be a physical mixture of methanol, shift, and dehydration catalysts. Selection of commercially available catalysts and the effect of their different ratios have been investigated. Some process variable results are presented. Commercial applications of the new process are illustrated. Further development of the process is currently underway. In the laboratory, the effects of temperature and feed composition are being studied in detail. Catalyst aging characteristics are also being defined. In addition, plans are being made to demonstrate the process in the Department of Energys Alternative Fuels Development Unit at LaPorte, Texas.