Biomass Gasification in Entrained Flow Reactor: Influence of Wood Particle Size

International audience ; The influence of beech-wood particle size on its gasification with O-2 was investigated in Entrained Flow Reactor (EFR) conditions. Experiments were performed in two facilities at very different scales: a drop tube reactor (DTR), and a pilot-scale EFR, the biomass feeding rates being set at 1 g/min and 90 kg/h respectively. Numerical simulation was used to bring a better understanding of the process. In the DTR, the carbon conversion into gas sharply increased with temperature for the larger particle powder - D-50/D-95 = 1230/1570 mu m - from about 20% at 800 degrees C to 80 % at 1400 degrees C. For the smaller particle powder - D-50/D-95 = 370/510 mu m - the conversion was of 80 % or higher whatever the temperature. At 1400 degrees C, the same conversion of about 80 % was reached for both powders and the gas composition was quite similar. The difference of conversion between the two powders was attributed to heat transfer limitations in the solid, and to a shorter residence time of the larger particles in the reactor. In the pilot-scale EFR, the different powder sizes - the smaller one being similar to the one used in the DTR, and up to D-95 of 1040 mu m - led to very close results in terms of temperature reached into the reactor, carbon conversion into gas and gas composition. For equivalent ratios (O-2/O-2 for stoichiometric combustion) of 0.36 and 0.45, the carbon conversion into gas was close to 100 %.