Study On Anaerobic Digestion Properties And Methaneyields Of Rape Straw

Straw as an important kind of biomass, its means of energy-oriented utilization isdiversity. Straw biogas is refers to under anaerobic conditions, multiple microbial interaction,straw degradation into biogas, and produce biogas liquids and biogas residues. The methanecontain of biogas is50%~70%, is a high grade clean fuels, renewable energy, can be usedfor cooking, lighting, power, etc. Therefore, use the straw to produce biogas can not onlyoptimize the energy structure, reduce non-renewable energy consumption, also has a goodeffects on economic, environment and ecology.The research use rape straw as fermentation material, used the device designed by thewestern scientific observation and experiment station of renewable energy in rural area of theministry of agriculture, to determine the anaerobic fermentation characteristics afterpretreatment by different NaOH quality fraction, explore the effects of gas production rulesand gas production in different ratio between rape straw and pig manure, explore the optimalconditions combination of the largest gas production under different levels of the4factorstemperature, total solid concentration, inoculum concentration and C/N value. The contentsand results of the research mainly include the following respects:1. The effects to anaerobic fermentation characteristics of rape straw after pretreatmentby different NaOH quality fraction. Different NaOH quality fraction pretreatment the rapestraw and then anaerobic digestion, the NaOH quality fraction respectively are2%,4%,6%,and8%, the results show that after pretreatment by different NaOH quality fraction, thecontents of crude fiber, acid washing fiber and acid washing lignin will all decrease, and6%quality fraction pretreatment is best.2. The effects of gas production rules and gas production in different ratio between rapestraw and pig manure. The results show that add the pig manure can significantly enhance thegas production of rape straw, when the proportion between rape straw and pig manure was1:1, the biogas yield can reach to95%than use pig manure as fermentation materials only,and at that condition the gas production is best.3. Characteristics of Biogas Production and Optimal Technological Parameters forAnaerobic Fermentation of Rape Straw. We used an orthogonal experiment design method todetermine the effects of fermentation temperature, total solids concentration, inoculum ratiosand C/N on accumulate biogas production of anaerobic fermentation, in order to explore the potential biogas production of rape straw. The results indicate that, the highest daily biogasproduction reached to4.25L/day (the volume of anaerobic digester is2.5L). During thewhole period of fermentation, the accumulate biogas production reached to70.665L, and thepotential of biogas production was up to0.36973L g-1. Through the analysis of variance(ANOVA) and range analysis, the optimum orthogonal design method was proposed to be ata fermentation temperature40℃, total solids concentration10%, inoculum ratios20%andC/N=25:1. The order of various factors to facilitate the impact of gas production arranged asfollowing: Fermentation temperature (A)>Total solids concentration (B)>C/N (D)>Inoculum ratios (C). Fermentation temperature has a significant effect on biogas production,while total solids concentration and C/N has no marked influence on it.