Assessment of a small sawdust gasification unit

The use of sawmill residues must be carefully analyzed to offer the best technical, economic and environmental alternative. The characterization (quantity, type, chemical and energetic analysis) of the residues generated, in addition to the energetic needs of sawmills, is essential to determine which technology is more suitable. This study shows that the technology of wood gasification can produce a gas able to be burned in an internal combustion engine, as long as it is appropriately cleaned. In order to assess the performance of the wood residues gasification process, a small, fixed bed, downdraft, stratified and open top gasifier was built. This gasifier, whose capacity was around 12 kg/h, has an internal gas recirculation, new to this type of gasifier, which can burn part of the gas produced to raise the gasification reaction temperature. Through the several parameters measured in the experiments, the mass and energy balances of the gasifier studied were obtained and its cold gas, global and mass conversion efficiencies were determined.