Characteristics Of Biogas Production By Mixed Fermentation Of Straw And Livestock Manure

The limitation of fossil energy has brought biomass energy into our eyes.China has been a big agricultural country since ancient times.The waste from agricultural production not only causes the waste of resources,but also pollutes the rural environment.Since the 18th National Congress of the Communist Party of China,the "green water and green mountains are gold and silver mountains" has made people more aware of the need to make use of these "misplaced resources".On the one hand,it can solve the problem of environmental pollution and properly dispose of these wastes;on the other hand,it can solve the problem of energy shortage in remote rural areas.In this study,several kinds of common agricultural wastes in the Central Plains rural areas-cow manure,pig manure,chicken manure,wheat straw,rice straw,corn straw.Anaerobic digestion process was carried out to explore the optimal material and ratio of waste and its optimal fermentation conditions.It lays a theoretical foundation for the utilization of biogas in rural areas.In the process of single raw material fermentation,the fermentation device uses 1 1 volumetric flask,the total mass of fermentation broth is 700 g,the mass of inoculum is 30%of the total mass of fermentation broth,and the total ts of fermentation broth is 8%.The fermentation time was 40 days and the fermentation temperature was controlled at 35?.Then,the effects of raw material ratio on the daily gas production,methane content and cumulative gas production of mixed raw material fermentation and the variation of pH in the fermentation process were explored.(1)In the chicken manure group,the optimal Ts ratio of chicken manure and wheat straw is 1:1,the optimal Ts ratio of pig manure and rice straw is 0.5:1,and the optimal Ts ratio of cow manure and corn straw is 0.5:1.(2)The change trend of pH is basically the same,and they all go through the process of decreasing pH,acidifying and enriching acid producing bacteria with small molecular acids,and then increasing pH,methanogens make full use of small molecular acids to produce methane.(3)It was found that as long as the fermentation process started normally,the methane content of the highest peak was not different,but the sTablele time was slightly different.In the case of daily use,materials will be supplemented,so the methane content can be kept at a sTablele level of 50%in the daily use of biogas fermentation.Finally,the orthogonal method was used to optimize the fermentation of multi-material mixture,which was carried out by taking the fermentation raw material,TS content of the liquid,the type of inoculated substance and the content of the inoculant as the experimental factors.The fermentation raw materials were chicken manure group,pig manure group and cow manure group,TS was 6%,8%and 10%,and inoculated materials were biogas liquid,activated sludge and composted cow manure respectively.The inoculated amount was 20%,30%and 40%respectively.Each group sets three repetitions,with the average as the final result.At last,we get the best material of anaerobic fermentation of agricultural waste-pig manure rice straw,and the best condition is that the fermentation material TS is 6%,the inoculant is 20%and 35? after the experiment fermentation.It provides theoretical basis and lays a foundation for the utilization of agricultural waste in rural areas.