Catalytic fast pyrolysis of demineralized biomass in a fluidized bed reactor: effects of acid-leaching and torrefaction pretreatment

In situ catalytic fast pyrolysis of pretreated wood was investigated using a fluidized bed reactor. The pretreatments included acid-leaching, torrefaction, and a combined pretreatment of acid-leaching followed by torrefaction. Acid-leaching reduced amounts of biomass minerals introduced into the process. However, acid-leaching caused agglomeration during pyrolysis leading to reactor defluidization. Acid-leaching also resulted in an upgraded bio-oil that was less deoxygenated compared to the corresponding bio-oil obtained from raw wood. Conversely, torrefaction had a beneficial effect leading to an increased yield of upgraded bio-oil without affecting its chemical composition. Torrefaction of the acid-leached wood prevented agglomeration, reversed the negative effect acid-leaching had on bio-oil quality, and gave an improvement in upgraded bio-oil yield. These effects, combined with the removal of biomass minerals that are detrimental to the catalyst, suggests acid-leaching coupled with torrefaction is a p...