Gasification and power generation characteristics of woody biomass utilizing a downdraft gasifier

Energy utilization from biomass resources has started to attract public attention as a method to reduce CO2 emissions. In this study, the characteristics of syngas production from biomass gasification were investigated in a downdraft gasifier that was combined with a small gas engine system for power generation. Syngas temperatures from the gasifier were maintained at a level of 700–1000 °C. When the air ratio for gasification was 0.3–0.35, the low heating value of syngas was 1100–1200 kcal Nm−3 and the cold gas efficiency 69–72%. Tar concentration in raw syngas was around 3.9–4.4 g Nm−3. Syngas combustion in the gas engine after purification showed that HC concentration was below 200 ppm, and NOx concentration was below 40 ppm in the exhaust gas.

► Rice husk gasification in downdraft gasifier.
► Syngas production performance with air ratio and temperature.
► Tar measurement in syngas.
► Combustion temperature and pressure in engine cylinder with load change.
► Pollutants concentration in engine exhaust gas with load.