The Optimization Of Hot-water Pretreatment And The Purification Of Sugar Liquior On Wheat-straw

In today’s society,with the increasing depletion of fossil fuels and other renewable resources and the worldwide demand for new energy,the development and utilization of renewable material and renewable energy has become a hot research topic.Biomass is a potential renewable energy.Lignocellulosic biomass can be transformed into monosaccharide by pretreatment and enzymatic hydrolysis,and then can be converted into biofuels,such as bio ethanol.However,the efficiency of enzymatic hydrolysis is restricted by natural degradation barrier of lignocellulosic biomass.Therefore,one of the main problems of biomass utilization is how to develop an efficient pretreatment method to break the natural barrier and promote the efficiency of enzymatic hydrolysis.In this paper,the preimpregnation process of wheat straw was studied,and its effect on the content of extraction and ash in wheat straw was analyzed.The preliminary study on the preimpregnation process was carried out by single factor experiment.Then the response surface method was used to model main influence factors,and the influence degree of each factor on the removal rate of the extractive in the wheat straw was analyzed,through which the optimal treatment conditions were obtained.The results showed the best:60 ~oC,60 min,pH=4 and 1 wt%EDTA.Under the best preimpregnation condition,the removal efficiency of the extract from wheat straw was 90.85%.The degree of influence is:reaction time>reaction temperature>the amount of pH>EDTA added to the solution.After preimpregnation,the wheat straw was pretreated with hydrothermal treatment.The content of xylose in hydrolysis solution was analyzed at different time and temperature,and the components in the solid residue that was obtained under optimal hydrothermal treatment conditions were analyzed.The results showed that the best hydrothermal pretreatment condition of preimpregnated wheat straw was that the treatment temperature was 180 ~oC,and the treatment time was 2.5 h.Under these conditions,the content of xylose in hydrolysate is the highest.The data of the paper shows that,after the preimpregnation of wheat straw,the content of xylose in the hydrolysate obtained by the hydrothermal treatment was obviously improved from 2.13 g/L to 3.17 g/L and the oligosaccharide content was improved from8.82 g/L to 13.13 g/L,and the content of hemicellulose in the solid residue after hydrothermal treatment was obviously decreased.Preimpregnation can improve the conversion efficiency of hemicellulose prepared by hydrothermal pretreatment.