Research On Ecological Regulation Factors And Assistant Technology On Low Temperature Biogas Fermentation

Aiming at the problem of the low efficiency and high energy consumption innorthern cold area, this paper proposes a method looking for the accelerator ofanaerobic methane producing progress between the temperature of25°C and35°C.From another aspect, it discusses how to take advantage of clean energy andpromote the efficiency of energy use to decrease fossil fuel consumption. It alsoexplores the use of biogas fermentation liquid and the way to reduce wasteemissions with the purpose of realizing the ecological civilization in agriculturalproduction.Microbial flocculant powder, tourmalinite, and nutritive salt were added in biogas fermentation system, and the influence on the methanogenesis was investigated.Results showed that microbial flocculant powder could contribute to anaerobic fermentation microflora; tourmalinite was capable of adjusting pH, which was beneficialto methanogens growth, and monthly average production of methane respectively increased by6.5%5.4%and11.4%. Also, proportions of TM6and RsaHF231in all microbial populations were much higher in comparison with blank control group; Trace of Cobalt would facilitate gas production through anaerobic fermentation and thebest performance was obtained with addition of6μmol/L Cobalt. The gas productionin high-efficiency phase was4.3mL higher than that from blank control group, but the gas production efficiency would evidently decrease when increasing Cobalt concentration to10μmol/L; Addition of sodium methoxide could evidently inhibit the growth of microbes in acid production phase, and the production rate decreased by3.7%and31.2%, respectively when the system was added sodium methoxide with concentration of25mmol/L and50mmol/L.Add biological flocculant powder, tourmaline and inorganic nutrient to biogasfermentation system and investigate their influence on process of producingmethane. The study shows that centrifugation has insignificant influence on thereducing sugar level, but those inorganic particles and cellulose, which is difficult todisintegrate by flocculant producing microorganisms, are removed most. From theperspective of production and demand rate, in comparison with traditional medium,mixing the traditional medium with20%biogas slurry processed by8000r/minrotate speed would increase the flocculation rate by4.39, and this number turns to2.93if the biogas slurry is processed by11000r/min. In addition, if the traditionalmedium mixed with40%biogas slurry which is processed by11000r/min rotatespeed, the flocculation rate would maintain nearly unchanged, increasing by0.07only. Even if growing of flocculant producing microorganisms in nutrient solution is not influenced by other ingredients in biogas slurry, after a long time, those stubbornorganic matters are still difficult to be utilized by flocculant producingmicroorganisms.Treating the Lin Hai farm as reference, simulate the heat dissipation model ofbiogas fermentation system and construct the physical model using cylinder, with7m radius and14m deep. Confirming the bondary conditions is based on thegeograhic environment、climatic environment and flow field type, and simulation isbased on the one-way flow model、non Newtonian fluid and stable structure。 Byconsidering the temperature of materials and that spread by biogas digester, theannual mean load of biogas digster is34.0kw, and the monthly maximum load is45.5kw. After initial calculation, the temperature of biogas fermentation system canbe maintained higher than25℃by using Insulation layer structure、solar energysystem and Soil Heat Pump, which keeps the activity of microorganism andefficiency of methane production.