Study Of Anaerobic Fermentation Of Comfrey And Gas Potential

Comfrey is also known as purple blades of grass, patriotic grass, which is called Russian Fodder Vegetables in the production, for the aggregate Boraginaceae spp. A continuous cropping can use 20 years, high yield, high regeneration ability. Spring, summer and autumn can be cut with as a long growing season, which can be cutting 4 to 6 times in North. Each crop is 0.4～0.5 million kg grass each mu. According to the mensuration , the dry matter of fresh comfry in flowering stage contained crude protein 24.3%, crude fat 5.9%, crude fiber 10.1% ,high nutritional value,(Jiang D Y etc 2007) .As the dual role of green and high-quality forage grass polymerization, in the vast rural areas and campus have a lot of planting . In order to make full use of this biomass resources, to improve the dung and agricultural forestry wastes pollution of the environment, to explore further application of the comfrey grass , this experiment has carried on mixed anaerobic fermentation to the comfrey together with peanut shell. Through the analysis of various factors in the process of test, searching for comfrey's changed rule in the medium anaerobic fermentation, this experiment will provide the powerful reference data for present's further research. The research content and the achievement mainly include the following several aspects:1. In order to study and compare the fresh green biomass wastes of anaerobic digestion characteristics, using independently designed anaerobic fermentation experiment installs, this experiment respectively takes the whitetip clover,comfrey, ternip leaves, and carrot leaves as the fermentation raw material, carries on the single-phase batch anaerobic digestion comparison test at 30±1℃condition. Through determining the four kinds of materials' total biogas production, the methane content and the pH value, the goal was to research the four kinds of materials' biogas production potential and characteristic, provide the design variable as well as the research direction for the comfrey in large-scale fermentation. The result indicated : comfrey's total production was the highest in the four kinds of materials,22655mL,and the gas potential is up to 252 mL/g·TS ,athough its fermentation starting time was long, the methane content was very stable .As a word,comfry had a good fermentation potential;2. To study the further different factors influence on comfrey anaerobic fermentation characteristic, do some research on comfrey fermentation through the different degree of pulverization, the different material contents and the different inoculum density conducts. Through measuring total biogas production, the methane content and the pH value, discuss the processing method to enables the comfrey anaerobic fermentation achieve the maximum conversion rate, the aim was to analyze various factors thoroughly to the comfrey anaerobic fermentation experimental study influence. The result indicates: the best inoculum density was 20% ,the best pulverization was slurry statement, the best material concentration was 8%.3. In order to study and explore the multi-factors influence on comfrey grass anaerobic digestion efficiency, take C/N ratio, material concentration and inoculum proportion as three primary factors, which influence the gas production and the methane content, the range of variation respectively will design as 18:1～32:1,4%～12% and 10%～30%. Through the two orthogonal revolving combination test, there will be influence equation and the change curve that three factors influence on various targets, and carries on the equation the e- xamination, optimized, the frequency analysis, the single factor and the double factor analysis and so on. The result indicates: It was different for single factor's influence on biogas production and the methane content; The material concentration was the most obvious to the two influence, the inoculum proportion was the next, C/N ratio was not very obvious; There are certain correlations within various factors, he different two factor mutual influence on biogas production and the methane content was also different. At 30±1℃,the optimum value of biogas production and it's rate respectively was 25870mL and 50.12%,which corresponds the material fluid density, the temperature and the sludge quantity are: (25:1,8%,20%) and (25:1,8%,20%). The predicted value of biogas production and it's rate respectively was 24166mL and 49.81%,which corresponds the material fluid density, the temperature and the sludge quantity are: (25.58:1,8.22%,20.01%) and (24.52:1,8.17%,22.65%).