An exploratory downdraft gasifier design with unique biomass pyrolysis and tar cracking mechanism is
evolved at Oklahoma State University. This design has an internal separate combustion section where
turbulent, swirling high-temperature combustion flows are generated. A series of research trials were
conducted using wood shavings as the gasifier feedstock. Maximum tar cracking temperatures were
above 1100 C. Average volumetric concentration levels of major combustible components in the product
gas were 22% CO and 11% H2. Hot and cold gas efficiencies were 72% and 66%, respectively.