以富碳原料为主要发酵原料的户用沼气投料技术

为解决以畜禽粪便等富氮原料为主要发酵原料的不足,探索以农作物秸秆等富碳原料为主要发酵原料的利用技术。介绍户用沼气以富碳原料为主要发酵原料应采取不同的处理办法及投料技术。     

农村秸秆与粪便发酵产氢的研究

选取10种常见的农业有机废弃物:稻草、玉米秆、小麦秆、大麦秆、蚕豆秆、黄豆秆等秸秆以及猪粪、牛粪、鸡粪、马粪等粪便作为原料,采用批量发酵工艺,控制发酵料液的pH值在适宜范围内,进行厌氧发酵产氢的研究.试验结果表明,在厌氧条件下,采用批量发酵工艺,控制发酵温度为25℃左右,以农作物秸秆、畜禽粪便为原料,以沼气发酵后的厌氧活性污泥为天然产氢菌种的来源,以乳酸调控发酵料液pH值为4.5～5.5,可以获得洁净能源--氢气.     

沼气推广不可松懈

沼气是有机物质发酵后产生的可以燃烧的气体。它的主要成分是甲烷。人工制取就是利用人工建造的沼气池,将农作物的秸秆、杂草、树叶和人畜粪便投入池内进行发酵而产生沼气的过程。沼气可用来烧水煮饭,点灯照明。还可以发电。前些年在我国广大农村普遍推广沼气生产和应用。特别是南方农村,在沼气的生产和应用方面取得     

分散原料沼气集中供气运行分析

我国规模化沼气工程存在原料单一、产气率低、装备落后等技术瓶颈,西南地区沼气原料来源分散、成分复杂,因此需要开发新的多种原料混合发酵的新模式来提高沼气工程厌氧消化效率。本工程通过全混式厌氧发酵两级工艺共同厌氧消化如秸秆和畜禽粪便等分散原料,形成新的沼气和发酵剩余物利用模式。结果表明,在30 d稳定运行期间,600 m³厌氧发酵罐每天可消纳猪粪7.9 t、浓污水8.2 t及农作物秸秆0.2 t,日产气量为900 m³,混合原料发酵的容积产气率达1.5 m³/(m³∙d)。     

"二池三改"庭院生态模式初探

农作物秸秆作为一种生物质资源，曾经作为原料应用于沼气发酵．但由于其在沼气生产过程中存在出渣麻烦等问题，在目前的沼气建设过程中大多都避开了对农作物秸秆的使用。秸秆青贮氨化发展畜牧业，同样是秸秆利用的一条途径，但由于其单一性，综合效益较低，     

我国秸秆沼气工程发展现状与趋势

秸秆沼气的发展不仅可实现农业废弃物资源循环利用、改善农村环境和温室气体减排,而且还能解决畜禽粪便沼气工程面临的地域与原料限制问题,受到全国范围的广泛重视。文章简述了我国现有的秸秆沼气工程的工艺技术种类和特点,介绍了秸秆沼气发展中存在的问题,并展望了秸秆沼气的发展趋势。     

生物质燃料制备技术分析比较

生物质能由于其数量庞大,对环境影响小,是可再生能源的重要组成部分。生物质燃料来源包括农作物秸秆、薪柴、禽畜粪便、城镇垃圾和工业有机废弃物等。生物质固体成型技术、生物质液体燃料转化技术以及生物质制取气体技术是常用的生物质燃料制备方法,针对不同地区和应用,采取不同的燃料形态,充分利用可再生资源,减轻对石油的依赖、缓解环保压力。     

利用沼气技术治理大中型畜禽场污染

利用厌氧消化技术处理禽畜场有机废弃物是对废弃物进行减量化、资源化和无害化处理的一项重要措施。 沼气工程的环境效益体现在输入部分和输出部分两个方面,在输入部分,通过对畜禽粪便进行厌氧消化,减少了污染,承担了社会成本,应当得到一定的补偿。在输出部分,用沼气发电可以替代常规电力,减少有害气体排放,同样应该得到支持和鼓励。     

福建省农村有机废弃物及沼气潜力评估

根据2003年福建省统计年鉴统计数据,计算了福建省农村有机废弃物以及其沼气潜力。目前,我省每年可有各种畜禽粪便100.31×106t(TS=20%),可产沼气96.8亿m3;农作物秸秆10.35×106t,60%可以用来产沼气,可产沼气12亿m3。按我省120万户农户计算,户均可拥有沼气量为9080m3,可完全解决农村生活用能。     

大型工业沼气停止产气处理技术探讨

到1994年底,全国已建成的583处大中型沼气工程,无论是以工业废水为原料,还是以畜禽粪便为原料,其工艺流程设计合理,发酵装置设备先进,在发酵原料充足和运行条件稳定的情况下,都能正常发酵产气。但某石油化工总厂的大型工业沼气工程于1995年5月发生了停止产气的故障,经采用快速富集培育高温新菌种的处理技术,一个多月时间就恢复了正常发酵供气,为管理好大型工业沼气摸索了经验,现总结如下。     

Photobiostimulation of anaerobic digestion by laser irradiation and photocatalytic effects of trace metals and nanomaterials on biogas production

Biogas generation from the latent energy in biomass is one of the most attractive renewable energy sources. This can be attributed to the environmental friendly nature of the process and its less energy requirements. This article reviews the anaerobic digestion of biomass (livestock manure and crop residues) for biogas and methane production as a source of renewable energy. Furthermore, this study investigates the enhancement of biogas and methane production using light and laser radiations. The laser radiation accelerates bacterial division and growth, where this process is termed as “photobiostimulation.” Additionally, laser radiation photoactivates the inactive enzymes. The results of this literature review showed that the irradiation of methanogenic bacteria with laser sources increased the biogas production by one and a half fold the traditional method of biogas production. The simultaneous irradiation of both nanomaterials and methanogenic bacteria using laser radiation increased the biogas volume by twofolds the biogas volume resulted from the traditional method of biogas production.     

Evaluation of biogas production from different biomass wastes with/without hydrothermal pretreatment

Municipal biomass waste is regarded as new available energy source, although it could cause serious environmental pollution. Generally, biogas recovery by anaerobic digestion was seen as an ideal way to treat biomass waste. Different types of biomass waste have different biogas production potential. In this paper, cow manure, pig manure, municipal sewage sludge, fruit/vegetable waste, and food waste were chosen as typical municipal biomass waste. In addition, hydrothermal pretreatment was used to accelerate digestion and increase biogas production. Biochemical methane potential (BMP) test was used to evaluate biogas production for raw biomass and hydrothermal treated waste. Raw materials of fruit/vegetable and food waste show higher methane production than that of cow manure, pig manure, and municipal sewage sludge. After hydrothermal pretreatment at typical condition (170 °C at 1 h), the biogas production of pig manure, cow manure, fruit/vegetable waste, and municipal sewage sludge increased by 7.8, 13.3, 18.5, and 67.8% respectively. While, for treated food waste, the biogas decrease by 3.4%. The methane yield of pig manure, fruit/vegetable waste, and municipal sewage sludge increased by 14.6, 16.1, and 65.8%, respectively. While, for treated cow manure and food waste, the methane decrease by 6.9% and 7.5%.     

Biogas production from municipal sewage sludge (MSS)

Biogas is produced by anaerobic (oxygen free) digestion of organic materials such as sewage sludge, animal waste, and municipal solid wastes (MSW). As sustainable clean energy carrier biogas is an important source of energy in heat and electricity generation, it is one of the most promising renewable energy sources in the world. Biogas is produced from the anaerobic digestion (AD) of organic matter, such as manure, MSW, sewage sludge, biodegradable wastes, and agricultural slurry, under anaerobic conditions with the help of microorganism. Biogas is composed of methane (55–75%), carbon dioxide (25–45%), nitrogen (0–5%), hydrogen (0–1%), hydrogen sulfide (0–1%), and oxygen (0–2%). The sewage sludge contains mainly proteins, sugars, detergents, phenols, and lipids. Sewage sludge also includes toxic and hazardous organic and inorganic pollutants sources. The digestion of municipal sewage sludge (MSS) occurs in three basic steps: acidogen, methanogens, and methanogens. During a 30-day digestion period, 80–85% of the biogas is produced in the first 15–18 days. Higher yields were observed within the temperature range of 30–60°C and pH range of 5.5–8.5. The MSS contains low nitrogen and has carbon-to-nitrogen (C/N) ratios of around 40–70. The optimal C/N ratio for the AD should be between 25 and 35. C/N ratio of sludge in small-scale sewage plants is often low, so nitrogen can be added in an inorganic form (ammonia or in organic form) such as livestock manure, urea, or food wastes. Potential production capacity of a biogas plant with a digestion chamber size of 500 m³ was estimated as 20–36 × 10³ Nm³ biogas production per year.     

我国生物燃气高效制备技术进展

本文从发酵原料拓展、预处理和厌氧消化工艺等三个方面对我国生物燃气高效制备领域的最新研究成果进行了介绍与评述。重点介绍了高固体浓度、固态、两相、混合发酵等4种高效厌氧消化工艺;鉴于我国正处于生物燃气产业化发展初期,从生物燃气高效制备技术方面对今后的研究重点给出建议。     

A comprehensive review on pretreatment of microalgae for biogas production

Use of microalgal biomass for renewable energy production has gained considerable attention in the world due to increasing global energy demand and negative environmental impacts of nonrenewable fossil fuels. Anaerobic digestion is one of the renewable technologies that microalgal biomass is converted into biogas by anaerobic archea. One of the main drawbacks of using microalgal biomass for biogas production is that certain types of microalgae has rigid cell wall characteristics, which limits accessibility of anaerobic archea to microalgal intracellular organic matter during hydrolysis phase. This limitation lowers efficiency of biogas production from microalgal biomass. However, introducing pretreatment methods prior to anaerobic digestion provides disruption of rigid microalgal cell wall and improve biogas yields from microalgal biomass. The objective of this paper was to review current knowledge related to pretreatment methods applied prior to anaerobic digestion of microalgal biomass. Efficiency and applicability of pretreatment methods mainly depend on type of microalgae, cell wall characteristics, and cost and energy requirements during pretreatment process. In this review, various type of pretreatment methods applied to microalgal biomass was discussed in detail with background knowledge and literature studies in their potential on maximization of biogas yields and their cost effectiveness, which is important for large‐scale applications. In the view of current knowledge, it was concluded that each pretreatment method has a relative contribution to improvement in biogas production depending on the type of microalgae. However, energy and cost requirements are the main limitations for pretreatment. So, further studies should focus on reduction of cost and energy demand by introducing combined methods, novel chemicals, and on‐site or immobilized enzymes in pretreatment to increase feasibility of pretreatment prior to anaerobic digestion in industrial scale.     

Biogas generation potential by anaerobic digestion for sustainable energy development in India

The potential of biogas generation from anaerobic digestion of different waste biomass in India has been studied. Renewable energy from biomass is one of the most efficient and effective options among the various other alternative sources of energy currently available. The anaerobic digestion of biomass requires less capital investment and per unit production cost as compared to other renewable energy sources such as hydro, solar and wind. Further, renewable energy from biomass is available as a domestic resource in the rural areas, which is not subject to world price fluctuations or the supply uncertainties as of imported and conventional fuels. In India, energy demand from various sectors is increased substantially and the energy supply is not in pace with the demand which resulted in a deficit of 11,436 MW which is equivalent to 12.6% of peak demand in 2006. The total installed capacity of bioenergy generation till 2007 from solid biomass and waste to energy is about 1227 MW against a potential of 25,700 MW. The bioenergy potential from municipal solid waste, crop residue and agricultural waste, wastewater sludge, animal manure, industrial waste which includes distilleries, dairy plants, pulp and paper, poultry, slaughter houses, sugar industries is estimated. The total potential of biogas from all the above sources excluding wastewater has been estimated to be 40,734 Mm³/year.     

香蕉秸秆资源化利用的研究进展

对香蕉秸秆在纤维生产、堆肥、饲料、气化和厌氧发酵等方面的利用情况进行了综述,指出了香蕉秸秆厌氧发酵生产沼气是其资源化和能源化利用的途径和潜力。我国香蕉秸秆年产沼气潜力高达4亿m3,其推广和应用将产生巨大的经济、社会和生态效益。     

Optimization of biogas production by anaerobic digestion for sustainable energy development in Zimbabwe

There is increasing international interest in developing low carbon renewable energy technologies. Biomass is increasingly being utilized as an energy source throughout the world. Several modern technologies have been developed that convert biomass to bioenergy. Anaerobic digestion is a mature energy technology for converting biomass to biogas, which is a renewable primary energy source. Biogas is a robust fuel that can be used to supply heat, electricity, process steam and methanol. There are vast biomass resources in Zimbabwe that have good potential for biogas production by anaerobic digestion. However, anaerobic digestion is not being optimally used as a biomass conversion technology in the country. This paper presents an overview of biogas production in Zimbabwe and outlines technical options that can be utilized to optimize biogas production by anaerobic digestion in the country.     

Prospective application of farm cattle manure for bioenergy production in Portugal

Biogas is a promising renewable fuel, which can be produced from a variety of organic raw materials and used for various energetic purposes, such as heat, combined heat and power or as a vehicle fuel. Biogas systems implementation are, therefore, subjected to several support measures but also to several constraints, related with policy measures on energy, waste treatment and agriculture. In this work, different policies and policy instruments, as well as other factors, which influence a potential expansion of Portuguese biogas systems are identified and evaluated. The result of this analysis shows that the use of the cattle manure for biogas production is still far from its potential. The main reason is the reduced dimension of the Portuguese farms, which makes biogas production unfeasible. Various options are suggested to increase or improve biogas production such as co-digestion, centralized plants and modular plants. Horizontal digesters are the most suitable for the typical Portuguese plant size and have the advantage of being also suitable for co-digestion due to the very good mixing conditions. Mesophilic anaerobic digestion due to a more robustness, stability and lower energy consumption should be the choice. The recent increase in the feed-in tariffs for the electricity production based on anaerobic digestion biogas is seen as a political push to this sector.