The Option Of Methane Production’s Technology By Anaerobic Fermentation Of Mixed Materials

Methane is a kind of new energy which is anaerobic fermentated by animal manure, crop stalks and other materials for human beings. However, due to the reasons of single raw material and the shortcomings of insufficient nutrients, there is not much room of improvement for fermentation in methane. But the mixed materials’fermentation not only can provide the adequate nutrients for the microorganism, but also can make the best use of excess organic waste, such as kitchen waste and municipal solid waste, etc. It can reduce the organic waste pollution for the environment, and turn the waste into wealth, provide clean energy for mankind. But mixed materials’fermentation has a lot of constraints, such as the ratio of materials, temperature, pH value, C/N and other factors. Comparing with other studies, this research selected the straw, kitchen waste and manure as the fermentation’s materials, and chose the materials ratio, C/N, TS concentration as the factors to research. Finally this artical got the optimum process conditions by using response surface methods.In the first place, this article selected the straw, kitchen waste and pig manure as the selected materials, analyzed the physical and chemical properties of the three materials, developed the pilot program of straw and manure, straw and food waste, kitchen waste and manure, and carried out the tests of straw and manure, straw and kitchen waste, kitchen waste and manure.Secondly, this article analyzed the gas production, gas production rate, changes in wood cellulose of each test,and got the the optimum conditions by analyzing the total gas production in the method of response surface. After that, we developed the pilot program of three mixing materials, and got the optimum conditions by response surface. Finally, we carried out the verification tests by the theoretical value.The conclusions by the experiments:(1)In the experiments of mixed straw and pig manure, we got the optimal parameters by response surface: the ratio of raw materials (straw: manure)=1.19, the best carbon and nitrogen ratio of 20.32, the best TS concentration of 10.10%, the best gas production forecast for the 26448.2mL. Predict gas production rate 155.58mL / g. (2)In the experiments of mixed straw and kitchen waste, we got the optimal parameters by response surface: the ratio of raw materials (straw: kitchen waste) =1.29:1; C/N (N ratio) =20.42; TS (dry matter concentration) =10.07%. Best of methane gas production is expected to 21431.7mL, birth rate 126.06mL/g.(3)In the experiments of mixed straw and pig manure, the phenomenon of over acidification occurred in the second day and the third day in the condition of adjusting the pH value.In the next week, the experiment did not restart, it can be illurstrated that kitchen waste should not be mixed with pig manure in anerobic fermentation.(4)In the experiments of three mixed materials, we got the optimal parameters by response surface: the ratio of raw materials (food waste content) = 1:0.5:0.5 (25% ); C/N (carbon and nitrogen ratio) = 20.17; TS (dry matter concentration) = 9.99%. Best of methane gas production is expected to 29179.6mL, birth rate 171.65mL/g.(5)In the experiments of validating conclusions, the total gas production and the rate of gas production is 26480mL and 155.76mL/g in the experiments of mixed staw and manure; the total gas production and the rate of gas production is 21390mL and 125.82mL/g in the experiments of mixed staw and kitchen waste; the total gas production and the rate of gas production is 29230mL and 171.94mL/g in the experiments of three mixed materials.The three groups of experiments concluded that the verification tests are very close to the theoretical value, there is some reference value.