Deconstructing biomass resistance for improving pyrolytic sugars via γ-valerolactone pretreated bamboo coupled with fast pyrolysis

Pyrolytic sugars, as significant fermentable sugars for the production of fuel ethanol, can be fleetly prepared by biomass fast pyrolysis. However, both the biomass inherent resistance and the interaction of compositions restrain the formation of pyrolytic sugars during pyrolysis. To overcome the above bottleneck and improve the yield of pyrolytic sugars, γ-valerolactone (GVL) pretreatment of bamboo coupled with fast pyrolysis was proposed. The effects of reaction temperatures, concentration of acid catalyst, pyrolytic parameters and kinetics on the distributions of sugar compounds were systematically investigated in this process. The experimental results demonstrated that the GVL pretreated biomass effectively eliminated the inherent resistance due to the removal of lignin (16.5 wt%) and hemicellulose (16 wt%). In addition, the content of alkaline and alkaline earth metals significantly decreased from 0.25 wt% of untreated bamboo to 0.01 wt% of the pretreated sample. Subsequently, the selectivity of levoglucosan effectively raised from 9.1 % of untreated bamboo to 70.3 % of GVL pretreated bamboo, and the content of levoglucosan from fast pyrolysis of GVL pretreated bamboo increased 20.2 folds as compared to untreated bamboo.