Study On The Technology Of Ultramicro Pretreatment By Straw Biomass And The Feasibility Study Of Hydrogen Production

Cellulosic biomass is rich resource, it can converse into hydrogenthrough direct or indirect fermentation pathway, so china has a larger advantage inresearch and development of the straw cellulose conversion technologies for hydrogenproduction, and has very important practical significance on the development ofalternative energy and protecting the ecological environment. The bottleneck that usestraw biomass for fermentation hydrogen production is the hydrolysis of lignocellulose instraw, the pretreatment is a key link in hydrogen production process and an importantobstacles to hydrogen production economical by the straw biomass, therefore, it isnecessary for the systematic research into the cellulose structure in the different types ofstraw biomass and the technology of straw biomass ultramicro pretreatment process.This paper was financially supported by the National Natural Science Foundation(No.50976029)“Research on the ultrastructural biomass hydrogen producing processand metabolic hot”, utilized the reducing sugar amount as reference, optimized theprocess, observed and analysed surface morphology and changes in composition andstructure of the material after smashing with scanning electron microscope, infraredspectroscopy, X-ray diffraction,etc. Through comprehensive consideration of all thefactors involved, determined the best raw material type and the best pretreatmentconditions as hydrogen production from straw biomass materials. Use biomasssubstances after ultramicro pretreatment for hydrogen producing experiments to furtherverify the technical feasibility of hydrogen production from enzymolysis liquid of strawbiomass after ultramicro pretreatment. Finally, analyzed the output and use-cost ratio (ΔB/ΔC) in the ultramicro pretreatment process of photosynthetic hydrogen production andoptimum utilization process to study the economic feasibility, this paper is designed toprovide reference and a basis for photosynthetic hydrogen production by straw biomassafter ultramicro pretreatment. The results showed that:（1）It appeared that the ball milling ultramicro pretreatment caused significant damage to cellulose structure of different types of straw biomass, it can be found thatcorncob was the best raw material for hydrgon production due to its loose structure,porosity and the biggest cellulose content, the less obvious of lignin package, and thebiggest reducing sugar yield after ball milling and enzymatic hydrolysis, saccharificationrate up to46.88%, to determine corncob as the best raw material for hydrogen productionafter ultramicro pretreatment.（2）Through single-factor and orthogonal tests, can obtain the optimum ball millingtechnological conditions, and the order of each factors on reducing sugar yield which are:ball/powder weight ratio, ball milling time, the raw materials initial particle size. Byvariance analysis, the ball/powder weight ratio is the most significant factors. It canobtain the optimum ball milling technological conditions through orthogonal tests, whichare: raw materials initial particle size,0.45mm, ball/powder weight ratio,20:1;ballmilling time,2h.（3）FTIR analysis showed the components of cellulose, hemicellulose and lignin aredifferent in different types of straw biomass after milling pretreatment, and theabsorbance are also significant differences. Through the X-ray diffraction of theultrastructural cornstalk and corncob revealed that the intensity of reflections for the ballmilling ultra-structural cornstalk and corncob was significantly decreased relative to theparent material, ball milling technology can significantly lessen overall crystallinity, thediffraction peak position of the cornstalk and corncob basically the same.Through the SEM analysis, found that after ball mill crushing straw cell wall waseffectively opened, microstructure changed, specific surface increased, structure becameloose and porous. These properties changes could increase cellulase accessibility,improve the straw degrees of saccharifying rate, make the hydrogen producing capacityincrease efficiency. Through the analysis of the corncob particle size distribution rangein the ball milling process of orthogonal test, obtained the relationship between theoverall changes in the size range and the reducing sugar yield, the more the reducingsugar yield, the smaller the particle size distribution, the lower the reducing sugar yield,the bigger the particle size distribution, to verify the significant effect on particle size ofthe reducing sugar yield of enzymatic hydrolysis of straw biomass after ultramicropretreatment. Analyzed the specific surface area for each group ball milled corncobcombined of particle size distribution can be seen, the smaller the particles of ultrastructural particles, the larger the specific surface area, and the greater the reducingsugar yield.（4）Vaccinated photosynthetic bacteria in enzymatic hydrolysis of straw biomassafter ultramicro pretreatment for hydrogen production, the law of the size of cumulativehydrogen production of various types of straw are accorded with the rule of its enzymatichydrolysis reducing sugar yield, and identified that the reducing sugar yield of strawbiomass enzymatic hydrolysis can be effectively used for biological hydrogen productionprocess, and identified the corncob is the best raw material in the selected five differentkinds materials.（5）Through the analyze of the economic feasibility of the ball milling ultramicropretreatment process, it can be seen that the maximum value of ΔB/ΔC appeared in theinitial particle size of0.125mm, and the milling time of0.5h.