Air gasification characteristics of unused woody biomass in a lab-scale bubbling fluidized bed gasifier

In this study, the gasification characteristics of four types of unused woody biomass and one waste wood in a lab-scale bubbling fluidized bed gasifier (Diameter: 0.11 m, Height: 0.42 m) were investigated. Effect of equivalence ratio (ER) of 0.15-0.3 and gas velocity of 2.5-5 U0/Umf are determined at the constant temperature of 800 °C and fuel feeding rate of 1 kg/h. The silica sand particle having an average particle size of 287 μm and olivine with an average particle size of 500 μm were used as the bed material, respectively. The average product gas composition of samples is as follows; H2 3-4 vol.%, CO 15-16 vol.%, CH4 4 vol.% and CO2 18-19 vol.% with a lower heating value (LHV) of 1193-1301 kcal/ Nm3 and higher heating value (HHV) of 1262-1377 kcal/Nm3. In addition, it was found that olivine reduced most of C2 components and increased H2 content compared to silica sand, resulting in cracking reaction of tar. The non-condensable tar decreases by 72% (1.24 → 0.35 g/Nm3) and the condensable tar decreases by 27% (4.4 → 3.2 g/Nm3).