Key Technology And Application Mode For The Co-production Of Biogas And Organic Fertilizer By Ecological Fermentation

The development and utilization of renewable clean energy is particularly important under the double pressures of energy shortage and environmental pollution. Biomass energy as a new renewable energy is becoming more and more attention. Although microbial fermentation biogas is a kind of effective method among all kinds of biomass utilization methods, it produce a large number of biogas slurry which is not easy to transport and handling. The biogas slurry is rich in amino acids which is the organic substrate of producing organic fertilizer. It has become an important subject to how to realize biogas and biogas manure coupling production achieving ecological fermentation and ensure the quality of biogas production and biogas manure at the same time.This paper focused on the research of production processes and application mode of biogas and organic fertilizer production by ecological fermentation and the greenhouse tunnel air fertilizer combined device, and completed the production run experimental research. The energy balance of the ecological greenhouse fermentation system was analysised, and energy flow chart was drew which was to optimize the ecological economic fermentation temperature. The paper aslo conducted the research of biogas slurry pretreatment method and fertilizer efficiency and put forward ecological fermentation biogas and biogas manure combined application mode in xixia county in henan province kiwi fruit production areas. The main results as followed:(1) According to raw material types and regional characteristic, the structure and function of biogas and fertilizer coupling production device was optimized and researched, and designed a kind of biogas and fertilizer coupling production device-greenhouse tunnel biogas fertilizer combined device including fermentation units, solar greenhouse, auxiliary heating units. The fermentation unit volume of greenhouse tunnel biogas fertilizer combined device was 1000m3. The solar greenhouse combined with tunnel fermentation system which make biogas fermentation temperature improve and Chi Rong biogas rate reach 0.8 m3 / m3·d, and raw material gas rate is 0.3 m3 / kg using raw material return and gas stirring. Fermentation period for 30 days using the device will produce biogas 1800 m3.(2) The heat balance of the ecological fermentation greenhouse was analyzed to establish the energy flow mathematical model of biogas fermentation engineering greenhouse using "black box" method, according to the law of conservation of energy., The stability of the energy flow was determined through the researches. As far as possible to raise efficiency of utilization of solar energy and auxiliary energy conversion in order to increase the output of greenhouse system. Through the greenhouse heat balance analysis and calculation, the reasonability of system structure and the weak link in the process of production was found which was benefit to put forward improving measures.(3) A mathematical model of ecological fermentation economic temperature was established. In the a series of fermentation conditions, temperature was the key factor that influence the rate of methane gas. Certain insulation measures must be taken to keep the biogas engineering for high gas rate, but the insulation measures increased the cost of fermentation at the same time. So the fermentation temperature is very important to improve the economic benefits of biogas project. Using mathematical analysis method, the biogas reactor system was analysized and basic mathematical model was established according to the law of conservation of energy and mass balance in the classical thermodynamics. It was concluded that the temperature at which the economic efficiency optimization, namely economic fermentation temperature. Economic fermentation temperature will Provide a scientific reference for PID control of biogas engineering practical application.(4) The method of negative pressure evaporation concentrated biogas slurry was presented in this paper, and the corresponding negative pressure evaporation device was designed. The results show that: when biogas slurry was heating concentrated, the lower the temperature of biogas slurry was, it was the more benefited to avoid the loss of nitrogen phosphorus and potassium in the biogas slurry, and the greater the vacuum degree was, the more easy biogas slurry was evaporated. When the vacuum degree was 0.065 Mpa, biogas slurry concentration rate could reach 26.5%, and biogas slurry organic fertilizer products which was producted by the technology were qualified.(5) Based on ecological agriculture industry value chain analysis, biogas and fertilizer combined production mode was constructed based on the value chain of the ecotype of kiwi fruit. It not only realize biogas and fertilizer combined production, but aslo ensure production quality and efficiency of kiwi fruit. It provided a new innovation model reference for the development of ecological agriculture, and implemented benign coordinated operation during biogas and fertilizer combined production, kiwi fruit planting, agricultural production and environment. Actual operation and energy balance analysis showed that the ecological kiwi biogas fertilizer power plant design was reasonable,and pretreatment method was proper. It was an innovation model which was suitable for large scale operation and application.