农村户用沼气技术(3)

第三集 沼气池管理技术 本集重点介绍农村家用沼气池管理方面的技术。 35问：建好沼气池以后如何管理好是非常重要的事情，那么，沼气池的管理都包括些什么呢？     

农村户用沼气技术(1)

自从生态家园富民计划实施以来，广大农民朋友参与生态农业建设的热情很高，也有一些农民朋友修建了沼气池以后发现问题却不知道怎么办。本刊以问答形式向广大读者介绍一些农村家用沼气技术的基本常识。[编者按]     

农村户用沼气技术(4)

第四集沼气配套产品与维修 农业部实施的生态家园富民计划，对广大农民的日常生活带来了好处，改变了传统的生活方式，实现了家居清洁化。实现家居清洁化要有相关的设备，为了广大农民朋友更好地使用与沼气相关的设备，本集重点介绍沼气配套产品使用知识。     

专业化配套是农村户用沼气建设的必然要求

随着国债农村户用沼气项目的进行，各地呈现出建设沼气的热潮。2004年，全国新增农村沼气户103万户，如此大规模的建设，配套产品的质量显得尤为重要。根据设计要求，混凝土沼气池使用寿命为20a，配套产品的设计寿命也应为20a，才能实现真正的配套，尤其是与混凝土紧密结合的导气管、地埋的输气管等不易更换的配件的质量，直接影响沼气池的使用寿命。如何保证沼气池的设计使用寿命，笔者认为，专业化配套是农村户用沼气发展的必然要求。     

渭河上游黄土丘陵地区农村户用沼气建设的环境经济效益分析

渭河上游的黄土丘陵地区经济贫困、环境脆弱、生活能源短缺,生物质的过量消费成为生态环境退化的重要因素。文章通过问卷调查获取相关数据,并建立计量模型,评估户用沼气建设工程对农户生活能源总体结构的影响,进而分析其生态经济效益。结果表明,沼气对农户生活能源结构的转换升级作用明显,生态经济效益显著,每口8 m3沼气池年产气量为300 m3,每年创造生态经济效益591.32元,其中生态环境效益231.88元,经济效益359.44元,减少农户现金支出153.39元。     

尤溪县农村户用沼气建设现状、问题与对策

通过对尤溪县农村户用沼气建设现状进行调查,根据农村户用沼气发展存在的问题,提出农村户用沼气建设的发展对策,又好又快地推动农村沼气事业的发展。     

福建省农村户用沼气建设存在的问题与对策研究

针对福建省近年来农村户用沼气建设中所面临的问题进行分析与归纳,并对进一步建设和发展农村沼气提出相应的措施和对策。     

农村户用沼气对环境影响的指标体系与评价

以客观性、系统性、定量性、比较性、效益性为原则,采用属性逐层分解法,建立农村户用沼气的环境评价指标体系,利用层次分析法对户用沼气对环境的影响进行评价,得出结论:农村户用沼气对各项环境指标的影响均为正或为零,各项指标影响程度由弱到强依次为大气环境(0)或水资源(0)、土地质量(0.034)、农村居民的健康状况(0.045)、动植物资源(0.2405)、农村居民的居住环境(0.6975)、农村居民的生活条件(1.1417);农村户用沼气对农村社会环境的影响程度(2.16)远大于对自然环境的影响程度(0.2755);农村户用沼气对环境影响的综合评价值为2.4355,达中度有利影响。     

沼气国债项目之"三改"技术方案设计

2003年、2004年我国分别安排国债资金10亿元支持农村沼气建设。项目建设要求以“一池三改”为基本项目单元，即每户建造一个户用沼气池，并与改造厕所、改造畜禽栏舍和改造厨房同步设计，同步施工。在生产实践中，”一池三改”项目建设存着在工作难度大、改造标准不高、统一规范困难等问题。如何从技术上提高“三改”的实用性和使用效果，达到规范化施工，     

我国农村沼气工程建设将进一步提速

日前,国务院确定将农村沼气作为进一步扩大内需的措施之一,今年中央将追加投资,使今年新增户用沼气池超过500万口。     

A decision support system for technologies of rural electrification

An interactive computer program has been developed to determine and to evaluate the optimal design of electricity distribution systems in rural areas. The program considers the costs and benefits of grid electrification, isolated diesel generators and centralized photovoltaics. It provides support for decisions on choices of technology. The program optimizes within the context of long-term load and system expansion; it runs on a 384K CPU microcomputer.     

A survey of renewable energy technologies for rural applications

The availability of modern energy has long been recognized as one of the requirements for rural economic development. The recent advances that have been made in renewable energy technologies have broadened their applicability despite the recent decline in world oil prices. In this paper, we summarize the technology status of renewable energy technologies (photovoltaics, wind energy, hydro, and biomass technologies) that are considered appropriate for rural areas. In addition, we discuss the economic and institutional constraints that inhibit their widespread dissemination in rural areas.     

Biogas/photovoltaic hybrid power system for decentralized energy supply of rural areas

Biomasses created from natural resources such as firewood, charcoal and forest crops are still the main source of energy in many communities in the developing countries of the world. The absence of modern techniques, in terms of energy conversion and the lack of resource planning, places a great burden on the environment, not only in terms of deforestation but the polluting residual emissions created by the burning of such fuels. Even in some developed countries, it is possible to find rural areas that have no access to the conventional national electrical grid. The lack of this facility is detrimental to the social and economic development of any country or community. Renewable energy systems have been used in many cases to mitigate these problems. The present paper introduces the concept of an alternative Hybrid Power System configuration that combines photovoltaic modules and digesters fuelled by goat manure as the basis for rural sustainable development. Attention is drawn to the Northeast Region of Brazil, one of the largest semi-arid regions in a single country. The regional conditions of Northeast of Brazil are not unique, suggesting that other countries of a similar nature would benefit from the same energy system.     

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.     

The potential of renewable energy technologies for rural development in Lesotho

The potential and utilization of renewable energy technologies (RETs), and energy analysis in Lesotho with emphasis on the contribution of solar energy technologies (SETs) is presented. The heavy reliance of the country on imported fossil fuel coupled with the growing demand for electricity and declining wood fuel supplies call for alternative sources of energy. Taking the average global solar radiation that ranges from 15 to 20 MJ/m² and cognizant of the short falls of other renewable energy sources in Lesotho, this paper focuses on the application of solar energy and associated developmental issues. The paper provides a statistical analysis of the energy demand and identifies areas of further growth for SETs. Various application areas of solar energy and their contribution to development in Lesotho together with future prospects for use of solar energy are also discussed. An analysis of the relative merits of using photovoltaic (PV) devices over other renewable energy sources in Lesotho is presented. It is argued that with proper economic support and utilization of efficient RETs, developing countries like Lesotho can meet their basic energy demands and alleviate the problems of energy shortages.     

Optimal mix of technologies for rural India: The lighting sector

Despite the obvious associated social benefits, lighting energy for rural areas of India has been largely ignored. Very little attention has been given either to improving efficiencies of existing lighting technologies or to developing alternatives. Comparing technologies for lighting which are both rational and practical for those living in developing countries is difficult owing to the problems of quantifying the social value and assigning rankings based on the quality of the lighting service provided. In the paper, an attempt is made to develop a framework for evaluating the relative economics of some of the common lighting technologies, and this is then incorporated into a linear programming framework to obtain the least-cost option for satisfying the lighting energy demand of a village subject to various constraints in the context of rural areas.