| Straw as a kind of high-quality biomass energy, It plays an important role to improve China’senergy structure and mitigate global climate change. However, because of the enchasing structure ofstraw lignin and cellulose，the degradation of anaerobic fermentation is not efficient, the digestion timeis long and the gas production rate is low. All of those become the technical bottleneck of developingthe straw anaerobic fermentation industrialization.In order to solve the above problem, using rice straw as the research object, through rigorousscientific testing and accurate data processing, experiments were carried out to study the biogasproduction by anaerobic fermentation of rice straw after percolation degradation. Main conclusions areas follows:1. The optimum conditions of rice straw percolation degradation. Pre-treatment by acidificationand hydrolysis is the key technique for the biomethanation process. In order to make the percolationprocessing technology to get better application in the high-efficiency degradation of straw，by singlefactor and orthogonal test, the optimum conditions was: solid-fluid ratio of1：8, fermentationtemperature of37℃, urea concentration of3%, and Tween-80concentration of0.2%. Through thepercolation-degradation, the pH of the reaction system was maintained at7-7.5，much hemicellulose inrice straw was degraded, cellulose and lignin were degraded. Electronic scanning display: compactstructure of rice straw surface mastoid and the like was almost completely destroyed, and deep longcells were exposed and disintegrated degree.2. The optimum process for anaerobic fermentation of rice straw. Through single factor analysismethod, It was studied that the influence of nitrogen source, urea addition, total solid content on the ricestraw anaerobic fermentation in the middle temperature conditions. The results showed that theoptimum fermentation conditions were: urea content of4%, total solid content of5%. The averagemethane content was about63%, the gas production was about220mL/g TS after anaerobicfermentation.After anaerobic fermentation, TS content of rice straw decreased from54.50%to43.78%, cellulosewere decreased largely, hemi-cellulose and content of lignin were increased slightly, It showed thatcellulose was mainly degraded in the process of anaerobic fermentation. After anaerobic fermentation, the content of three kinds of elements nitrogen, phosphorus andpotassium has been balanced in the straw, nitrogen, phosphorus and potassium content of three elementswere increased to3.7%,1.0%,2.9%, which has a good fertility characteristics, widely used in ruralareas suitable for farming.In addition, different forms of nitrogen, urea addition on the rice straw anaerobic fermentation test,It was found that the fermentation before or after ammonium nitrogen in the proportion of total nitrogenwere larger, but ammonium nitrogen content would be decreased, nitrate nitrogen content would beincreased after fermentation. |
