Basic Study On The Movable-and-assembled Style Device Producing Energy Sources By Utilizing The Excrement

With the development of livestock and birds breeding industry in China, the environment pollution arising from excrement produced by livestock and birds is more serious, and the disposal of large amount of excrement has become the urgent affair. Among all the existing excrement -disposal technologies, producing biogas by utilizing the excrement is the best method adapting to the situation of China. It goes like the old saying—killing two birds with one stone that the biogas resulting from the anaerobic ferment of the admixture consisting of excrement and such agricultural castoffs as straw, not only solves the pollution problems, but also can provide cleanly and safe energy sources that make up for the shortage of fuel in most rural areas.The local government has attached high importance on the pollution issue that the circumjacent environment was polluted seriously by the excrement from most intensive pig farms on the scale of 500—1000 in Fuling, Chongqing. In order to achieve the pig husbandry’s sustained development, it’s obligatory to mend entironment, dipose the castoffs innocuously with utilization as resources, and keep harmony between swine production and environment protection. In allusion to this status, a new excrement—disposing and biogas—producing device—movable-and-assembled style device porducing energy sources by utilizing the excrement was designed.Whereas the "unit can" is the core of this device, the experiment was carried out respectively in accordance with the technics conditions which affect the bigas’ ferment, such as raw materials’ concentration, ferment temperature, pressure, acidity and alkalinity, and inoculability quantity. Based on the study, the results were as follows:（1） Raw materials’ concentration’s influence on biogas output: the higher the raw materials’ concentration, the more the total biogas output in the ferment process; if the concentration is excessively high, it’s likely that the assimilation will not be sufficient（ferment not enough）, which will bring on the waste of the raw materials.（2） Ferment temperature’s influence on biogas output: the relationship between temperature and biogas output is not simply linear, if other factors are in normal range and the device is in normal ferment conditon. At 30—35℃, the aerogenous rate is highest. The normal ferment temperature should not be less than 10℃, otherwise the biogas output would be affected a lot.（3） Pressure changing’s influence on biogas output: the influence dosen’t obey obvious rule, howerver, if the pressure changing is very big, the biogas output’s fluctuating will be big too. The effcet is best if control the pressure in a stable range（4—5kpa）.（4） Acidity and alkalinity（PH values）’s influence on biogas output: if the PH values maintain 7.0--8.0, the ferment will take place normally. When the PH value is 7.8, the aerogenous rate can achieve 0.236 m³·m^-3d^-1; When the PH value is 5.5, the aerogenous rate will decreaed to 0.236 m³·m^-3d^-1. The aerogenous rate is a bit high when the PH value varied from 7.5-8.0.（5） Inoculability quantity’s influence on biogas output: the experiment groups in which raw materials’ inoculability quantity is more than 30%, produce biogas nearly to each other. So it’s better that the inoculability quantity keeps at about 30%. At this moment, not only the inoculant and expenses cannot be wasted, but also the catabolism rate and using rate of raw materials can be improved.The above analysis will give a guidance to the design of the unit can. This device works based on the tenet-- breaking up the whole into parts and making the waste become useful, and solves the problem that the excrement from intensive pig farms in rural areas is so mass that the disposal falls short of the criterion. This device also plays an important role in protecting the entirontnent and promoting the sustained development of agriculture.