Selective sequential fractionation of biomass for quantitatively elucidating the compositional factors affecting biomass fast pyrolysis

In order to eliminate the cross effects among various components of biomass during fast pyrolysis, a selective sequential fractionation protocol for lignocellulosic biomass is developed for quantitatively elucidating the effects of individual components on biomass fast pyrolysis. Corncobs and pines were sequentially treated by water washing, acid washing, dilute acid pretreatment and organosolv fractionation for selective removal of extractable ash, structural ash, hemicellulose, and lignin fraction, respectively. It is demonstrated that the selective sequential removal of individual components exerted significant impacts on the yields of typical pyrolytic products, such as light oxygenates, furans, cyclopentenones, phenols and anhydrosugars, especially levoglucosan. Structural ash and lignin in corncobs and extractable ash and lignin in pines significantly inhibited the formation of levoglucosan, whereas hemicellulose in pines promoted the levoglucosan yield. Hemicellulose in corncobs and structural ash in pines had fewer impacts. It is thus concluded that inhibiting the catalytic effects of ash and selective removal of lignin are the most key factors determining levoglucosan yield from biomass fast pyrolysis. This study can provide theoretical guidance for rational screening and design of efficient pretreatment methods prior to biomass fast pyrolysis for enhancing yield of desired chemicals.