Influence of Bed Medium on Bubbling Fluidized Bed Reactors for Biomass Gasification: Experimental Study

This research provides a contribution to biomass gasification technology development and to its establishment into the market as mature and functional technology, competitive for large and medium-scale applications. In this article, an experimental analysis of Bubbling Fluidized Bed Reactors (BFBR) for power generation with different sand mixtures is presented. This experimental study is based on a 50 kW and a 10 kW BFBR, respectively, with inner diameters of 10 cm and 22.2 cm. In the experiments, three different bed sands (molochite, silica and alumina) have been tested attending to their properties, such as operating temperatures, bulk density for fluidisation, homogeneous grain size and commercial availability. According to the implemented tests, the obtained results demonstrate that molochite (calcined kaolin) has best effectiveness as bed additive for optimizing the reactor pressure drop, operating temperature, mean particle size and fluidization conditions. On the other side, the most appropriate range for the relation between the sand bed height and the reactor inner diameter to reduce the energy consumption was determined. Finally, the distributor pressure drop and the range of pressured drop were experimentally evaluated.