Technoeconomic analysis of a low CO2 emission dimethyl ether (DME) plant based on gasification of torrefied biomass

Two models of a dimethyl ether (DME) fuel production plant were designed and analyzed in DNA and Aspen Plus. The plants produce DME by either recycle (RC) or once through (OT) catalytic conversion of a syngas generated by gasification of torrefied woody biomass. Torrefication is a mild pyrolysis process that takes place at 200–300°C. Torrefied biomass has properties similar to coal, which enables the use of commercially available coal gasification processing equipment. The DME plants are designed with focus on lowering the total CO2 emissions from the plants; this includes e.g. a recycle of a CO2 rich stream to a CO2 capture plant, which is used in the conditioning of the syngas.