为评估不同物料相同发酵条件下的产沼气特性,该文研究了玉米秸秆、小麦秸秆、水稻秸秆、香蕉秸秆、鸡粪、牛粪和猪粪7种原料的基本特性及发酵情况。元素分析结果表明7种原料均不适宜直接发酵,且粪便原料的理论产气潜力优于纤维质原料。...为评估不同物料相同发酵条件下的产沼气特性,该文研究了玉米秸秆、小麦秸秆、水稻秸秆、香蕉秸秆、鸡粪、牛粪和猪粪7种原料的基本特性及发酵情况。元素分析结果表明7种原料均不适宜直接发酵,且粪便原料的理论产气潜力优于纤维质原料。组分分析表明,纤维质原料中香蕉秸秆的可降解组分含量最高,达76.13%,粪便原料中鸡粪的易降解有机物含量最高,为59.72%。发酵试验结果表明,香蕉秸秆和鸡粪的甲烷产率分别为186.10和224.85 m L/g,BDA(biodegradability)分别为41.42%和33.28%,消化时间(T90)分别为9.5和7 d,为两类原料中产气潜力最佳的原料。基于月累计甲烷产量和Gompertz模拟结果,鸡粪和香蕉秸秆降解速率快,累计产气量高,分别达867.28 m L/g和528.92 m L/g。结果表明鸡粪和香蕉秸秆最适合作为沼气发酵的原料。展开更多
Using lignite samples, selected from Zhaotong basin, Yunnan province, China, as the parent source, simulating experiments of lignite biogas were conducted with 0.1% methanol, 5 mg/L yeast extract and 0.2 mol/L sodium ...Using lignite samples, selected from Zhaotong basin, Yunnan province, China, as the parent source, simulating experiments of lignite biogas were conducted with 0.1% methanol, 5 mg/L yeast extract and 0.2 mol/L sodium acetate solutions as the exogenous substance respectively. Variation characteristics of gas production, gas composition, VFA content and activity of coenzyme 1：42o in the simulated process were analyzed to discuss the influence of different substrates on lignite biogas generation. The results show that 0.1% methanol and 5 mg/L yeast extract solutions increase VFA contents in the biogas generation system （p 〈 0.05） and inhibit coenzyme F420 and methanogen activities significantly, so they decrease both gas amounts （p 〈 0.05） and CH4 contents （p 〈 0.05）. 0.2 mol/L sodium acetate solution activates coenzyme F42o and methanogen activities and improves the efficiency of enzymatic reaction, so the gas quantity （p 〈 0.05） and the CH4 content （p 〈 0.01） increase significantly. Therefore, sodium acetate can be one kind of good exogenous substance for the generation of lignite biogenic gas.展开更多
The effect of tea saponins (TS) on rumen fermentation and methane emission was examined using an in vitro gas production technique named Reading Pressure Technique. Three levels of TS addition (0, 0.2, 0.4 mg/ml) were...The effect of tea saponins (TS) on rumen fermentation and methane emission was examined using an in vitro gas production technique named Reading Pressure Technique. Three levels of TS addition (0, 0.2, 0.4 mg/ml) were evaluated in the faunated and defaunated rumen fluid. Compared to the control, TS addition decreased the 24 h gas production in the faunated rumen fluid, but had a minor effect on gas yield in the defaunated rumen fluid. The TS significantly reduced methane production in vitro. In the faunated rumen fluid, 0.2 or 0.4 mg/ml TS decreased the 24 h methane emission by 12.7% or 14.0%, respectively. Rumen fluid pH value was affected neither by TS addition nor by defaunation. The TS addition had only minor effects on volatile fatty acids, but the yield and pattern of volatile fatty acids were greatly affected by defaunation. While the molar proportion of acetate was not affected by defaunation, the propionate was significantly increased and the butyrate significantly decreased. Ammonia-N concentration and microbial protein yield were influenced by TS inclusion and defaunation. Inclusion of 0.4 mg/ml TS increased the microbial protein mass by 18.4% and 13.8% and decreased the ammonia-N concentration by 8.3% and 19.6% in the faunated and defaunated rumen fluid, respectively. Protozoa counts were significantly reduced by TS inclusion. The current study demonstrated the beneficial effect of TS on methane production and rumen fermentation, and indicated that this may be due to the effect of the associated depression on protozoa counts.展开更多
This work addressed the multi-objective optimization of a biogas production system considering both environmental and economic criteria. A mixed integer non-linear programming(MINLP) model was established and solved w...This work addressed the multi-objective optimization of a biogas production system considering both environmental and economic criteria. A mixed integer non-linear programming(MINLP) model was established and solved with non-dominated sorting genetic algorithm Ⅱ, from which the Pareto fronts, the optimal technology combinations and operation conditions were obtained and analyzed. It's found that the system is feasible in both environmental and economic considerations after optimization. The most expensive processing section is decarbonization; the most expensive equipment is anaerobic digester; the most power-consuming processing section is digestion, followed by decarbonization and waste management. The positive green degree value on the process is attributed to processing section of digestion and waste management. 3:1 chicken feces and corn straw, solar energy, pressure swing adsorption and 3:1 chicken feces and rice straw, solar energy, pressure swing adsorption are turned out to be two robust technology combinations under different prices of methane and electricity by sensitivity analysis. The optimization results provide support for optimal design and operation of biogas production system considering environmental and economic objectives.展开更多
Bio-methane,as a promising renewable green energy,the component and thermal value of which are very close to that of natural gas,indicates an enormous resource potential and could be employed as the alternative of fos...Bio-methane,as a promising renewable green energy,the component and thermal value of which are very close to that of natural gas,indicates an enormous resource potential and could be employed as the alternative of fossil energy through the development of agro-industrial integration and efficient bio-methane system. Establishment of high efficient agro-industrial integrated bio-methane system is an important component of the renewable energy system and also a significant way of emission reduction.展开更多
The Earth surface contains various oxic and anoxic environments. The later include natural wetlands,river and lake sediments, paddy field soils and landfills. In the last few decades, the biogeochemical cycle of carbo...The Earth surface contains various oxic and anoxic environments. The later include natural wetlands,river and lake sediments, paddy field soils and landfills. In the last few decades, the biogeochemical cycle of carbon in anoxic environments, which leads to the production and emission of methane, a potent greenhouse gas in the atmosphere, has drawn great attentions from both scientific and public sectors. New organisms and mechanisms involved in methanogenesis and carbon cycling have been uncovered. Interspecies electron transfer is considered as a crucial step in methanogenesis in anoxic environments.Electron-carrying mediators, like H_2 and formate, are known to play the key role in electron transfer. Recently, it has been found that in addition to the conventional electron transfer via chemical mediators, direct interspecies electron transfer(DIET) can occur. In this Review, we describe the ecology and biogeochemistry of methanogenesis and highlight the effect of microbe-mineral interaction on microbial syntrophy. Recent advances in the study of DIET may pave the way towards a mechanistic understanding of methanogenesis and the influence of microbe-mineral interaction on this process.展开更多
文摘为评估不同物料相同发酵条件下的产沼气特性,该文研究了玉米秸秆、小麦秸秆、水稻秸秆、香蕉秸秆、鸡粪、牛粪和猪粪7种原料的基本特性及发酵情况。元素分析结果表明7种原料均不适宜直接发酵,且粪便原料的理论产气潜力优于纤维质原料。组分分析表明,纤维质原料中香蕉秸秆的可降解组分含量最高,达76.13%,粪便原料中鸡粪的易降解有机物含量最高,为59.72%。发酵试验结果表明,香蕉秸秆和鸡粪的甲烷产率分别为186.10和224.85 m L/g,BDA(biodegradability)分别为41.42%和33.28%,消化时间(T90)分别为9.5和7 d,为两类原料中产气潜力最佳的原料。基于月累计甲烷产量和Gompertz模拟结果,鸡粪和香蕉秸秆降解速率快,累计产气量高,分别达867.28 m L/g和528.92 m L/g。结果表明鸡粪和香蕉秸秆最适合作为沼气发酵的原料。
基金supported by the National Natural Science Key Foundation of China (Nos. 41202119 and 41272177)the National Natural Science Key Foundation of China (No. 41202237)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Using lignite samples, selected from Zhaotong basin, Yunnan province, China, as the parent source, simulating experiments of lignite biogas were conducted with 0.1% methanol, 5 mg/L yeast extract and 0.2 mol/L sodium acetate solutions as the exogenous substance respectively. Variation characteristics of gas production, gas composition, VFA content and activity of coenzyme 1：42o in the simulated process were analyzed to discuss the influence of different substrates on lignite biogas generation. The results show that 0.1% methanol and 5 mg/L yeast extract solutions increase VFA contents in the biogas generation system （p 〈 0.05） and inhibit coenzyme F420 and methanogen activities significantly, so they decrease both gas amounts （p 〈 0.05） and CH4 contents （p 〈 0.05）. 0.2 mol/L sodium acetate solution activates coenzyme F42o and methanogen activities and improves the efficiency of enzymatic reaction, so the gas quantity （p 〈 0.05） and the CH4 content （p 〈 0.01） increase significantly. Therefore, sodium acetate can be one kind of good exogenous substance for the generation of lignite biogenic gas.
基金Project (No. 12665/R0) supported partly by Co-ordinated ResearchProjects from Joint FAO/IAEA Division, IAEA
文摘The effect of tea saponins (TS) on rumen fermentation and methane emission was examined using an in vitro gas production technique named Reading Pressure Technique. Three levels of TS addition (0, 0.2, 0.4 mg/ml) were evaluated in the faunated and defaunated rumen fluid. Compared to the control, TS addition decreased the 24 h gas production in the faunated rumen fluid, but had a minor effect on gas yield in the defaunated rumen fluid. The TS significantly reduced methane production in vitro. In the faunated rumen fluid, 0.2 or 0.4 mg/ml TS decreased the 24 h methane emission by 12.7% or 14.0%, respectively. Rumen fluid pH value was affected neither by TS addition nor by defaunation. The TS addition had only minor effects on volatile fatty acids, but the yield and pattern of volatile fatty acids were greatly affected by defaunation. While the molar proportion of acetate was not affected by defaunation, the propionate was significantly increased and the butyrate significantly decreased. Ammonia-N concentration and microbial protein yield were influenced by TS inclusion and defaunation. Inclusion of 0.4 mg/ml TS increased the microbial protein mass by 18.4% and 13.8% and decreased the ammonia-N concentration by 8.3% and 19.6% in the faunated and defaunated rumen fluid, respectively. Protozoa counts were significantly reduced by TS inclusion. The current study demonstrated the beneficial effect of TS on methane production and rumen fermentation, and indicated that this may be due to the effect of the associated depression on protozoa counts.
基金Supported by the National Natural Science Fund for Distinguished Young Scholars(21425625)the National Basic Research Program of China(2013CB733506,2015CB251403)+1 种基金the National Natural Science Foundation of China(U1610222)the Beijing Hundreds of Leading Talents Training Project of Science and Technology(Z171100001117154)
文摘This work addressed the multi-objective optimization of a biogas production system considering both environmental and economic criteria. A mixed integer non-linear programming(MINLP) model was established and solved with non-dominated sorting genetic algorithm Ⅱ, from which the Pareto fronts, the optimal technology combinations and operation conditions were obtained and analyzed. It's found that the system is feasible in both environmental and economic considerations after optimization. The most expensive processing section is decarbonization; the most expensive equipment is anaerobic digester; the most power-consuming processing section is digestion, followed by decarbonization and waste management. The positive green degree value on the process is attributed to processing section of digestion and waste management. 3:1 chicken feces and corn straw, solar energy, pressure swing adsorption and 3:1 chicken feces and rice straw, solar energy, pressure swing adsorption are turned out to be two robust technology combinations under different prices of methane and electricity by sensitivity analysis. The optimization results provide support for optimal design and operation of biogas production system considering environmental and economic objectives.
文摘Bio-methane,as a promising renewable green energy,the component and thermal value of which are very close to that of natural gas,indicates an enormous resource potential and could be employed as the alternative of fossil energy through the development of agro-industrial integration and efficient bio-methane system. Establishment of high efficient agro-industrial integrated bio-methane system is an important component of the renewable energy system and also a significant way of emission reduction.
基金partly supported by the National Natural Science Foundation of China(41630857)the National Basic Research Program of China(2016YFD0200306)
文摘The Earth surface contains various oxic and anoxic environments. The later include natural wetlands,river and lake sediments, paddy field soils and landfills. In the last few decades, the biogeochemical cycle of carbon in anoxic environments, which leads to the production and emission of methane, a potent greenhouse gas in the atmosphere, has drawn great attentions from both scientific and public sectors. New organisms and mechanisms involved in methanogenesis and carbon cycling have been uncovered. Interspecies electron transfer is considered as a crucial step in methanogenesis in anoxic environments.Electron-carrying mediators, like H_2 and formate, are known to play the key role in electron transfer. Recently, it has been found that in addition to the conventional electron transfer via chemical mediators, direct interspecies electron transfer(DIET) can occur. In this Review, we describe the ecology and biogeochemistry of methanogenesis and highlight the effect of microbe-mineral interaction on microbial syntrophy. Recent advances in the study of DIET may pave the way towards a mechanistic understanding of methanogenesis and the influence of microbe-mineral interaction on this process.
