论文部分内容阅读
Three major steps,i.e.pretreatment,hydrolysis and fermentation were common employed for conversion of lignocellusic biomass into fuel.The pretreatment efficiency is key factor for this process.The wet oxidation pretreatment process was investigated under alkaline conditions for fractionation of hemicellulose,cellulose,and lignin from poplar waste by this paper.The major sensitive factors on reducing sugar yield,such as pH,t,T and P (pH: initial pH,t: pretreated time,T: elevated temperature and P: oxygen pressure) were optimized.HPLC,scanning electron microscopy (SEM) and X-ray Diffraction (XRD) were used for characterization of hydrolyzates and to observe solid residues,respectively.Optimum conditions for hemicellulose solubilization and cellulose convertibility were for 60g L-1 poplar waste: initial pH 10,reaction time 15min,elevated temperature 195°C,and oxygen pressure 1.2MPa.Under these conditions,the cellulose and hemicellulose content of pretreated substrate was 63.26% and 2.77% respectively,the reducing sugar yield of cellulase hydrolysis was 46.75%.The substrate crystallinity declined 19.68% and the crystal structure was destroyed and a lot of holes and grooves appeared on the fiber surface.The xylose content in pretreated liquor is much higher than glucose,and some acetic acid,formic acid and furfural appeared in pretreated liquor because of the hexose and pentose degradation.