Expents On Biogas Production From Rimepeaut Hull Bny Anaerobic Fermentation

Peanut cultivation area in China ranks the second place in the world, but thetotal output of peanuts does the first. The output of peanut shells comes up to500tons peryear in China. Peanut shells are rich in nutrients, with good potential for development andutilization, but its use is mainly in feed development, food processing and other fields. Itwill be an efficient and rational way to realize the utilization of peanut shells to convertthem into energy substances (methane, for example.) with microbial anaerobic fermentationtechnology.The research on the use of straw for anaerobic fermentation has been reported bothdomestically and internationally. However, the raw material is mainly concentrated in thewheat straw, rice straw, cornstalks, etc. the fermentation technology using peanut shells toproduce biogas has been reported rarely. Therefore, taking peanut shells as raw materials, itspotential in biogas fermentation was researched in this paper. Also, the feasibility of biomassenergy conversion using peanut shells to produce biogas was discussed. According to theprinciple of response surface method, the parameters in pretreatment process for peanutshells were optimized using Box-Behnken model in Design-Expert software. The processparameters optimized configuration for biogas fermentation with peanut shells wereexplored by orthogonal experimental design. Further more, the effects of adding a certainpercentage of cow dung, pig manure and chicken manure on methane fermentation werediscussed. This will help to produce biogas though fermentation with peanut shells forlarge-scale application.The test results of peanut shells anaerobic fermentation to produce methane show thatthe potential for methane fermentation with peanut shells reaches to0.323m3kg-1. Thetests with response surface optimization shows that for the selected three pretreatment effectfactors, there is a certain synergy between any two. The granularity and pretreatment time isthe most obvious synergistic effect, followed by granularity and the concentration of addedalkali and the concentration of added alkali and the pretreatment time is the least. Theoptimum conditions obtained are as follows: the granularity of4.48mm, the massconcentration of added alkali of10.5%and biogas pretreatment time of6days. Theorthogonal experimental design results of process parameters optimization for anaerobicfermentation with peanut shells show that the fermentation temperature, total solids contentof the fermentation liquid, inoculum size and pH have different influences on the fermentation results. The fermentation temperature has a significant effect on biogas outputand methane production. Also, the total solid content affects the biogas productionsignificantly. The optimum conditions are as follows: fermentation temperature of35°C,the total solid content of20%, inoculum size (mass ratio) of1:1, pH value of7.5. Adding acertain percentage of cow dung, pig manure and chicken manure respectively has differenteffects on fermentation effect. The fermentation cycle may be shorten cow dung, chickenmanure and pig manure. Moreover, the potential for gas production is enhanced obviouslyby adding pig manure. Compared to each other, the best fermentation effect is adding cowdung, followed by chicken manure and pig manure is the worst.