Study On Anaerobic Digestion Properties And Process Technology Optimizations Of Corn Stalks

China is a big agricultural country, the crop straw in china is in large quantities, variety,wide distribution. Especially in more recent years, our agricultural has a good harvest, moreand more crop straw is produced. According to the survey statistics of department ofagriculture. The yield of crop straw is about700million tons in2010. Just one of those thingsis cornstalks, whose yield is about273million tons. In many places of our country, most ofcornstalks cannot be used effectively, they are be used as fuel, or be incinerated in the fielddirectly. If we incinerated the cornstalks in the field, it is not only waste the resources, butalso pollute the environment, impact the traffic safety, and it can cause fire accidents andother accidents. So how to use cornstalks as effectively as possible become a very importantproblem. Rational use the cornstalks can increase farmers’ income, and meet the requirementof the construction of new countryside. It has a good social benefits, economic benefits andenvironmental benefits. Cornstalks contain more than30%of carbohydrate,2%⁴%ofprotein and0.5%¹%of fat, so it is a good raw material of biogas production. But they havea high contains of lignin, cellulose and hemicellulose in cornstalks. They are difficult to bedegrade, so if we use cornstalks as raw material, it will has a low biogas productionefficiency.This research investigates the potential fermentation to produce biogas of different partsof cornstalks. We also investigate the potential fermentation to produce biogas if we usedifferent methods to pretreat the dry cornstalks and silage cornstalks. To improve theutilization rate of cornstalk, we will make a further research use the silage cornstalks as theraw material.This main research contents and conclusion are as follows:（1） The research on the characteristics of different parts of cornstalks on the Biogasproduction. The result shows that corncob has a good gas production potential. It has a totalbiogas production of of33480ml, with TS gas production of279ml/g,with daily biogasproduction of608.72ml, with average methane content of49.42%; The blade of cornstalkshas total gas production of31030ml, with TS gas production of258.6ml/g,with daily biogasproduction of564.2ml, with average methane content of55.65%; The leaf sheath ofcornstalks has total gas production of33020ml, with TS gas production of275.2ml/g,withdaily biogas production of600.4ml, with average methane content of47.44%. The bark of cornstalks has total gas production of33785ml, with TS gas production of256.5ml/g,withdaily biogas production of559.7ml, with average methane content of50.65%. The pith ofcornstalks has total gas production of26620ml, with TS gas production of221.8ml/g,withdaily biogas production of484.0ml, with average methane content of53.68%.（2） We pretreat dry cornstalks and silage cornstalks with NaOH and biogas slurry, do notdo any pretreat to another experimental group. Then we research on the characteristics ofanaerobic digestion. The result shows that if we do not do any pretreat to them. The drycornstalks has total gas production of52169ml, with TS gas production of434.7ml/g,withdaily biogas production of948.5ml, with average methane content of38.69%. The silagecornstalks has total gas production of57190ml, with TS gas production of476.6ml/g,withdaily biogas production of1039.8ml, with average methane content of42.57%. If we pretreatthem with NaOH, The dry cornstalks has total gas production of61056ml, with TS gasproduction of508.8ml/g,with daily biogas production of1110.1ml, with average methanecontent of45.00%. The silage cornstalks has total gas production of64445ml, with TS gasproduction of537.0ml/g,with daily biogas production of1171.7ml, with average methanecontent of47.82%. If we pretreat them with biogas slurry, The dry cornstalks has total gasproduction of57990ml, with TS gas production of483.3ml/g,with daily biogas production of1054.4ml, with average methane content of44.51%. The silage cornstalks has total gasproduction of64785ml, with TS gas production of539.9ml/g,with daily biogas production of1177.9ml, with average methane content of48.83%.（3） The process optimization research of anaerobic fermentation with silage. We selectedthe concentration of6%,8%,10%,12%, the C/N of20,25,30. the inoculum concentration20%,30%,40%, to confirm the conditions range of anaerobic fermentation. After that wemake a range analysis to the experimental data. The result shows that the primary andsecondary relations of affect sizes of the factors on anaerobic digestion of silage cornstalksare: concentrationâ†'the inoculum concentrationâ†'C/N. Comprehensive analysis from thetotal gas production and average methane content, the best pilot scheme is A₃B₂C₃, it is saidthat the concentration is10%, the rate of C/N is25, the inoculum concentration is40%is thebest process.