BIOMASS GASIFICATION IN BUBBLING FLUIDIZED BED: EFFECT OF BIOMASS TYPE ON SYNGAS PROPERTIES

The gasification characteristics of three different biomass feedstock samples (straw pellet, softwood pellet and torrefied wood chips) were investigated in this study. The effect of biomass type on gas composition, gas yield, lower heating value (LHV), carbon conversion efficiency, the amounts of tar and sulfur compounds were investigated in laboratory scale bubbling fluidized bed gasifier using air as a gasification agent and quartz as a bed material. Permanent gases were analyzed by gas chromatograph (GC) equipped with a flame ionization detector. The amounts of total sulfur and individual sulfur compounds (hydrogen sulfide, carbonyl sulfide and methyl mercaptane) were determined by UV fluorescence and GC PFPD (pulsed flame photometric detector) techniques, respectively. Conventional gravimetric (CEN/TS 15439) method was used for sampling and analysis of tar compounds. Torrefied wood chips produced much lower tar during gasification, in comparison to the softwood pellet sample. The syngas obtained from straw pellet had the highest calorific value, 4.40 MJ/Nm(3), while torrefied wood had the lowest calorific value, 3.50 MJ/Nm(3).