Effects of Different Gasifying Agents on Synthesis Gas Composition from Fluidized Bed Gasification using Raw and Torrefied Wood Sawdust

Gasification of raw and torrefied wood sawdust were performed in fluidized bed gasifier using three different gasifying agents namely air, steam and oxygen. The effects of different gasifying agents on synthesis gas composition, yield of synthesis gas and lower heating value (LHV) were investigated at various gasification temperature from 650 to 1100 °C. Based on gasification experimental results, raw wood sawdust from steam gasification produces the highest hydrogen gas composition (31.5%) at temperature of 850 °C followed by 30.9% hydrogen composition from oxygen gasification and gasification using air as agent only manage to produce around 18.1% hydrogen composition. Meanwhile the highest synthesis gas yield of 2.52 Nm3/kg and LHV of 9.31 MJ/Nm3 are obtained from torrefied wood sawdust using oxygen as gasifying agent. This indicates steam is preferable as gasifying agent for producing hydrogen rich in synthesis gas. Meanwhile torrefied biomass from oxygen gasification is feasible for obtaining higher yield and energy content of synthesis gas.