Characterization Of Biogas Preparation From Anaerobic Digestion Of Pear Residue And Bacterial Residue

Biogas engineering with anaerobic digestion technology as the core is an effective way to realize the harmless treatment and resource utilization of organic waste,and is an important source of renewable natural gas at home and abroad.In this thesis,the anaerobic digestion characteristics of pear pomace and fermentation residue of a bioengineering enterprise were investigated as raw materials to provide technical reference for the design and operation of related biogas projects.The study firstly analyzed the gas production characteristics of the two fermentation feedstocks using a batch-type anaerobic fermentation unit,and mainly investigated the changes of the cumulative gas production,methane volume fraction,p H and other parameters of the anaerobic fermentation process under different starting loads,fermentation temperatures and different ratios of biochar additions;then the Gompertz model was used to fit the anaerobic fermentation process of each experimental group,and the Then,the Gompertz model was used to fit the anaerobic fermentation process of each experimental group,and to predict the methanogenic potential,fermentation delay period and maximum methane production rate of each experimental group.The main findings are as follows:（1）Organic load and temperature are important factors affecting anaerobic fermentation,and after batch experiments,the medium temperature（38±1℃）fermentation conditions were most suitable for anaerobic fermentation of the Pear Pomace and the bacterial residue,at which temperature the optimal starting load of the Pear Pomace was 60.4 g/L,and the TS and VS methanogenesis rates of the experimental group reached 210.02 ml·g^-1 and 214.34ml·g^-1,respectively,under the anaerobic fermentation conditions of the medium temperature（38±1℃）,Both TS and VS methanogenesis rates in the B₃ experimental group with a priming load of 35.48 g/L were significantly higher（P<0.05）than the rest of the experimental groups,which were 225.19 ml·g^-1 and 229.81 ml·g^-1.（2）Biochar can enhance the anaerobic digestion process of organic waste mainly by improving the cumulative amount of methanogenesis and shortening the reaction lag period,which was 3.7%-9.51%higher,and the lag period was 10.5%-34.09%shorter in the experimental group with biochar addition,meanwhile,the strengthening effect of the anaerobic system was attenuated with the addition of biochar first increasing and then decreasing,and the experimental optimum biochar addition was 5%of the total solid mass.（3）Anaerobic fermentation of Pear Pomace and bacterial residue using a continuous CSTR anaerobic fermentation reactor showed the most efficient and stable gas production in the anaerobic fermentation system under the conditions of an organic load of 6.15 g/（L·d）for Pear Pomace and 4.35 g/（L·d）（measured as volatile solids）,351.17 ml·g^-1 for TS and358.37 ml·g^-1 for VS;The TS methanogenic rate of the residue was 365.21 ml·g^-1 and the VS methanogenic rate was 387.99 ml·g^-1.