Downdraft biomass gasifier design with an internal cyclonic
combustion chamber developed under this study showed
consistent performance in tar cracking temperatures, volumetric
gas concentration levels for CO and H2, and gasifier efficiencies.
Gasification tests using wood shavings showed average hot gas
and cold gas efficiencies of 73% and 67%, respectively, at the specific
air input rate of 542 kg of air/h-m2. Maximum tar cracking
temperatures were above 1100 C.