Characteristics of rice husk char gasification with steam

Biomass char gasification with steam refers to the reaction of the steam and biomass char under high temperature when the biomass char converts to combustible gas. Rice husk was selected as the raw material for char preparation. A gasification reactor was designed and built for the study of characteristics of rice husk char gasification with steam. Results show that the temperature is the primary factor that influences the steam gasification reaction of rice husk char. The conversion rate increases significantly from 27.7% to 90.73% with the temperature from 700 to 950 °C. H2 accounts for 46.9% of the product gas at 950 °C. The conversion rate of rice husk char increases with temperature. The conversion rate of rice husk char increases as the steam flow rate. H2 and CO gradually increase while CO2 and CH4 decrease as the steam flow rate. The conversion rate can be increased by decreasing particle size at low temperature, but the influence of the particle size becomes smaller above 900 °C. The reactivity of rice husk char prepared at low temperature is relatively high. Both surface reaction controlled shrinking core reaction model and homogeneous reaction model can describe the steam gasification reaction of rice husk char when the temperature is less than 850 °C. However, when the temperature is more than 850 °C, the diffusion through gas controls the overall reaction.