Influence of tree species and wood deterioration on downdraft gasifier performance

Abstract A preliminary systematic investigation of the influence of tree species and wood deterioration on the performance of a downdraft gasifier has been conducted. Four hardwood species (cottonwood, silver maple, black locust, and oak) were gasified in a commercial gasifier under similar operating conditions. Silver maple was used as a source of both ‘normal’ and deteriorated wood. The results indicate that tree species does not influence the dry feed rate or the dry gas heating value. However, differences in the dry gas and char yields were observed; these were attributed to variations between species in the volumetric percentage of vessels (macropores) in the wood structure. Deterioration resulted in a reduced gasifier throughout as compared to ‘normal’ wood; which is attributed to the chip bulk voidage reduction as a consequence of decay.