Air/steam Gasification of Residual Biomass in a 20 kWth Bubbling Fluidized Bed Reactor: Process Conditions and Gas Composition

In this work it is described the operation of a pre-pilot scale gasification facility composed of a bubbling fluidized bed reactor (BFBR, 20 kWth) and ancillary equipment. The BFBR has an internal diameter of 0.150 m and a total height of 2.2 m. The main characteristics of the gasification experimental facility are presented together with data on its operation with residual biomass and its mixture with plastics, and RDF. Experiments were performed at bed temperatures of 780 ºC and 825°C under atmospheric pressure, and equivalence ratio in range 0.22 to 0.26. The feed rate of biomass, and its mixture with plastic, and RDF, was in the range 1 to 5 kg/h, and air, air/steam, or steam mass flow rate was in range 5.5 to 7.7 kg/h. Compared to biomass gasification, the RDF and the mixture of biomass and plastic (LDPE) gasification produces a gas with lower concentration of CO and higher concentration of light hydrocarbons (in particular C2H4), higher LHV and H2:CO molar ratios. No major influence was observed in CGE (54% to 59%). Compared to air gasification, the addition of steam produces a gas with higher concentration of H2 (up to 44.4%v, N2 free) and lower concentration of CO. No significant effect was observed in LHV and CGE, but the H2:CO molar ratio increases significantly (up to 1.8 in steam gasification).