The Technology Design And Demonstration Of Straw Methane In Rural Areas

The crisis of energy globally becomes more and more serious. As the unique renewable carbon source, biomass can be converted into solid, liquid and gas fuel. Biomass energy is the most development potential and renewable energy which can be used to achieve zero emission of carbon. Its large reserve and wide distribution not only contribute to relieve the energy crisis, but also have a great impact on the control of greenhouse effect and reducing the environment pollution. China is a great agricultural country. As an important part of rural energy consumption in China, the development and utilization of biomass energy plays a significant role in national energy security and building a beautiful socialist countryside. In recent years, the utilization of biogas was widely promoted in China. The methods of straw utilization was from traditional combustion to centralized gas conversion.Although the construction of rural biogas in our country has been more and more, there still existed some problems and factors that restricted the development of rural biogas. The factors are mainly as followed, difficulty to move raw materials into the biogas pool, straw pool crusts and the low productivity rate of biogas.Through the study of technology of rural straw-biogas engineering, The large solid anaerobic reactors were designed which met with the engineering characteristics used crop straws as material. By optimizing the fermentation process, The biogas slurry reflux device was designed to prevent encrustation with the solar heating device ensuring the productivity rate of biogas. After fully mastering the basic design requirements of the construction, structures, and the security of straw-biogas engineering and supporting facilities, the large project of centralized supply biogas was built and used for demonstration in Nan Liuying Village, Wolong district, Nanyang city.The process of large centralized straw-biogas supply construction was as followed, farmers collected and pretreated straws of maize and wheat as raw materials, and then put raw materials into fermentation pools. At the same time, the livestock manure was mixed, diluted and poured into the fermentation pool. After the fermentation, the purified biogas will be supplied to the farms. The residue and biogas slurry would be discharged into the liquid pool and could be used as fertilizer. This process has the following characteristics, open type anaerobic reactors, biogas slurry reflux devices and solar heating devices.After running one year, the tracking survey was carried out for a month among three constructions of centralized supply biogas. The results demonstrated that the fermentation temperature of the three constructions stabilized around 28.9?34.7%, the percentage of total solid content 4.18%?4.18%, and the pH value around 7.0?7.3. TN, TP, COD and VFA of the three constructions were different. This demonstration project brought the huge social, ecological and economic benefits.