Design and Performance of a Biomass-based Polygeneration System for Simultaneous Dme and Power Production

The present work deals with the preliminary design, the simulation, and the assessment of the thermodynamic performance of a polygeneration system for the simultaneous production of a range of valuable chemical products (namely, di-methyl-ether (DME), methanol (MeOH), H2-CH4 mixtures with an H2 content up to 30 %, usually referred to as “hythane”) alongside the generation of multiple energy carriers such as heating and power. The system included a biomass gasification step, a steam cycle for power generation, an oxyfuel combustor, a syngas-to-DME section and a methanation section. A sensitivity study on the gasification section showed that low pressure oxygen/steam gasification at 950°C yields a good quality syngas with an H2/(CO+CO2) ratio of 0.97. A simple graphical method for fixed-bed reactor dimensioning is also presented.