(266e) Effect of Pretreatment on Biomass Pyrolysis for Better Quality of Bio-Oil
Yuan Xue, Joel Braden, Xianglan Bai
Biomass is recognized as an important sustainable resource for energy and chemicals. Typical biomass, such as agricultural wastes and forest residues, can contain up to 12% ash as received. As the major components of ash, alkali and alkaline earth metals (AAEM) naturally presenting in biomass are known to have strong detrimental effect on biomass pyrolysis by promoting char and gas formations. Washing biomass by diluted acid or directly infusing acid into biomass prior to pyrolysis can increase bio-oil yield and greatly improve sugar production. It has been considered that acid pretreatments improve biomass pyrolysis either by removing AAEM as acid soluble or passivating catalytic effect of AAEM. On the other hand, it has also been reported that pyrolysis of acid pretreated biomass reduces the recovery of lignin-derived phenolic monomers and oligomers. The acid pretreated biomass (either by acid-washing or acid-infusion) also easily agglomerates due to the formation of unknown melts during pyrolysis. Although various theories have been suggested, the effects of acid treatment on lignin and carbohydrates in AAEM containing biomass are still not well understood. In the present study, biomass is subjected to various types of pretreatments, including acid treatment, oxidative treatment and alkaline delignification to decouple the effects of AAEM on lignin and cellulose in biomass. The biomass pretreated under various conditions were characterized and further fast pyrolyzed. The overall goal of this study is to increase the quality of bio-oil from biomass pyrolysis through effective biomass pretreatment.