| China is a large agricultural country, and there are a variety of agricultural wastes, can be used as biomass energy development and utilization of resources is very rich, but usually a lot of agricultural wastes are as garbage, resulting in waste of resources and environmental pollution. So we can make use of anaerobic fermentation technology convert them into high-grade energy. Anaerobic fermentation system can effectively recover agricultural wastes, and it is an ideal system.In order to study and compare characteristics of anaerobic fermentation of agricultural waste, this paper uses independently designed anaerobic fermentation experiment installs ,and carries out a variety of anaerobic fermentation of agricultural waste at 30±1℃. Through the determination and comparison of key indicators the course of the experiment to explore the characteristics of the fermentation of raw materials, to find more and suitable raw materials for fermentation, there by enhancing the value of agricultural waste. Main research contents and results include the following:This paper studies three kinds of agricultural wastes (Bluegrass, stems and leaves of chayote and stems and leaves of tomato)as raw materials, anaerobic digestion tests were conducted and compared. The results show that: Bluegrass has longest gas production and the most cumulative gas production, stems and leaves of chayote is the second, stems and leaves of tomato is the worst. The cumulative production of bluegrass , stems and leaves of chayote and stems and leaves of tomato are 54830mL, 45360mL, 33090ml;Bluegiass and stems and leaves of chayote have a level of acid accumulation in the fermentation, but after the automatic adjustment of the system, they return to normal after a period of time, but stems and leaves of chayote recoveries slow, and its methane content is low, the methane content of bluegrass and stems and leaves of tomato is higher; Comparing gas production, methane, gas production potential and other indicators ,the bluegrass'synthetic performance is best.To further study the characteristics of anaerobic fermentation of bluegrass, this paper uses inoculation volume are 10%, 20%, 30% and 40% of the four gradient, and the fermentation concentration are 4%, 6%, 8% and 10% of the four gradient to do comparison tests, and discuss the affect of inoculation volume and fermentation concentration on gas production, methane and pH value. The results show that: When bluegrass'inoculation volume is 30%, fermentation concentration is 6%~8%, the effect of anaerobic fermentation is better.The bluegrass and pig manure are as raw materials of mixed fermentation .To put cumulative gas production and the average methane content as the index and select the C/N, fermentation density and inoculation volume three factors to do multi-factor tests, the three factors change in the range of 13 ~ 30,4 ~ 10% and 10 ~ 40%. Basing on the method of the two orthogonal revolving combination test, Regression equations of three factors on gas production and methane contents are built, and the influence law of how C/N, fermentation density and inoculation volume affect on gas production and methane contents is studied. The results show that: The main factors affecting gas production order of: the inoculation volume >the fermentation density >the C/N, the main factors affecting methane content order of: the inoculation volume >the C/N> the fermentation density .Various factors have some interaction, two different factors interact on gas production and methane content is different; Test data are analysed by using SAS data processing system, it can get the best technology of the raw materials (bluegrass and pig manure )of mixed to get better gas production: C/N is 23.06:1 , fermentation density is 7.35%, the inoculation volume is 29.02% , the theoretical value of mixed raw material's gas production is up to 38.06L; the best technology that can get higher methane content is: C/N is 23.64:1, fermentation density is 7.23%, the inoculation volume is 30.12%, the theoretical value of mixed raw material's methane content is up to 54.79%. |
