Biomass Gasification in Fluidized Bed at Pilot Scale with Steam−Oxygen Mixtures. Product Distribution for Very Different Operating Conditions

Biomass gasification in a fluidized bed with steam−O 2 mixtures has been studied in detail at pilot plant scale. The gasifier used was 15 cm i.d. and 3.2 m high, and it was fed with pine wood chips at flow rates of 5−20 kg/h. Main operating variables studied were gasifier bed temperature (780−890 °C), steam to oxygen in the feeding ratio (2−3 mol/mol), and gasifying agent (H 2 O + O 2 ) to biomass fed ratio (0.6−1.6 kg/kg daf). Product distribution here shown includes gas, tar and char yields, gas composition (H 2, CO, CO 2, CH 4, steam, ...) and heating value, tar composition and content in the flue gas, gas heating value, apparent thermal efficiency, etc. Under good operating conditions the following gas is obtained: tar content of 5 g/Nm 3, 30 vol % H 2, heating value of 16.0 MJ/Nm 3 (dry basis), gas yield of 1.2 Nm 3 (dry basis)/kg biomass fed.