Straw Black Liquor Steam Reforming in a Fluidized Bed Reactor.Effect of Temperature and Bed Substitution at Pilot Scale

摘要

Gasification via the steam reforming of straw black liquor (BL) was performed in a pilot-plant fluidized bed reactor.The effects of bed material replacement (from an initial bed of calcium carbonate to a bed composed of BL char) and bed temperature (575-640degC) on the dry gas composition,the dry gas lower heating value (LHV),gas yield,fraction of carbon to gas,and cold gas efficiency have been investigated.Although bed defluidization problems were experienced under the operating conditions tested,a medium heating value gas (with a dry gas LHV of approx8200 kJ/m~3 STP) (where STP indicates standard temperature and pressure) was obtained,composed mainly of H_2 (65 vol %) and CO_2 (30 vol %).Because of the high ratio of steam to biomass used,little influence of the reaction temperature on the gas composition was observed at >550degC.At 600degC,which is a temperature lower than that usually utilized in biomass gasification,approx2.2 m~3 STP/kg daf of gas production,75% carbon conversion to gas,and a cold gas efficiency of 90% were achieved,showing that the low-temperature steam reforming of BL could be a suitable process if bed defluidization can be overcome.