猪粪污水沼气发电工程的效益分析

猪粪长期以来作简单的有机肥使用,不仅污染环境,而且还存在着大量生物质能源浪费、肥效流失严重等问题。萧山市龙翔公司年产1.2万头供港猪养殖场,由于整个生产线采用集约化饲养和高架漏网结构,大量粪水集中,加之用水冲栏,污水量大,给周围环境造成严重的污染,仅1991年由于污染造成大量鱼死亡,直接经济损失达5万余元。为了从根本上解决猪粪污水污染问题,于1993年建造了500m~3猪粪污水沼气发电工程,发电能力75kW。经过三年来的运行使用,该工程各项技术指标均达到设计要求,获得了较好的经济、社会、环境、能源综合效益,为禽畜养殖场污水处理提供了示范。     

德国典型沼气发电技术及其借鉴

以5处沼气发电工程为例,介绍了德国典型的沼气发电技术,其普遍采用"混合厌氧发酵、沼气发电上网、余热回收利用、沼渣沼液施肥、全程自动化控制"的技术模式,通过该模式的实施,最终实现发酵原料的全方位综合利用;并通过电、热以及沼渣沼液的外售给工程运行带来收益,最终实现市场化运行。通过对此次考察相关情况的介绍与总结,以期为我国大中型沼气工程的发展提供一些借鉴。     

德国《可再生能源法》实施及调整对其沼气产业发展的影响分析

德国《可再生能源法》是推动其可再生能源发展的重要法律文件。本文介绍了该法规的出台背景,着重量化分析了自2004年以来德国《可再生能源法》四次修改调整对沼气产业发展的影响,包括德国新增沼气发电站数量和总装机容量、能源作物种植面积的变化以及补贴措施。分析结果表明,《可再生能源法》的调整对沼气产业的发展影响显著,该法规EEG-2004和EEG-2009强烈刺激了沼气产业的快速发展,而EEG-2012和EEG-2014则修正了沼气产业的过快发展。《可再生能源法》对上网电价补贴的合理制定,实施效果评估机制的建立和逐步引导沼气产业市场化机制的设计保障了德国沼气产业的健康有序发展。本文同时还讨论了德国案例对我国沼气发展的启示,对我国发展沼气产业政策提出了包括后端补贴在内的建议。     

大中型沼气工程的COD测定

化学耗氧量(COD)常用来评价水质的污染程度,在一定程度上代表水中所含被氧化的物质数量的一种概念。COD的测定对于河流和工业废水的污水处理是一个重要而快速测定指标。在甲烷发酵中,为了解发酵液中被氧化的合碳基质数量,及时掌握发酵的进程也是个重要参数。 测定COD有两种方法,即高锰酸钾法和重铬酸钾法,方法的选择取决于测试目的和污水浓度。如果只要对废水中有机物进行相对比较,不必要求测定氧化率很高,可采用操作简便而再现性好的高锰酸钾法。如果要尽可能表示废水中有机物总量,或希望从中去除COD量来推算甲烷产量时,应选择氧化率高的重铅酸钾法。此外,对含有悬浮有机物进行测定,必须选择重铬酸钾法。因此,在大中型沼气工程的测试中,应采用重铬酸钾法。     

持续高速发展的德国沼气产业

德国高度重视可再生能源的发展,把发展沼气产业作为推进能源结构转型、提高资源利用水平、促进经济社会可持续发展的战略重点。文章介绍了德国的可再生能源与沼气政策目标以及德国可再生能源法的进展。     

中德沼气工程比较

在考察中国和德国沼气工程现场及查阅大量文献报道的基础上,就中德沼气工程发展现状、政策法规、技术进展(包括发酵原料、发酵工艺、沼气净化、沼渣沼液利用以及沼气发电)等方面进行了比较,提出了中国农业废弃物沼气工程的差距以及改进的措施。     

农村沼气工程动态发酵工艺的调控

以厌氧活性污泥滞留和附着膜技术为基础，在研究探明沼气发酵装置内物料流态和运行机理的基础上，研制出旋动式沼气发酵装置；与发酵装置相配套，探索出自流进料、旋流布料、强回流搅拌、固菌成膜的动态连续发酵工艺，解决了静态不连续发酵工艺存在的菌料分布不均和出料困难等技术问题。工程运行显示，动态发酵工艺比静态发酵工艺年均产气量提高31％～72．4％，实现了全年产气、持续莉用、方便管理的目标。     

沼气发电技术及沼气燃料电池在我国的应用状况与前景

沼气发电技术是一种清洁的发电技术。文章针对目前我国已有的沼气发电技术进行了技术评价,综述了这种技术的发展现状与近年来的应用情况;燃料电池也是一种新型高效、清洁的发电技术,文章对以沼气为燃料的燃料电池技术进行了介绍,对我国沼气利用技术的发展具有参考价值。     

实例分析大中型沼气工程能源效益

以扬州某畜禽养殖场大中型沼气工程为例,从各种能源替代类别差异的视角,利用等效能量替代的方法对大中型沼气工程产生沼气的能源替代效益进行分析,同时计算沼气发电余热回收利用所节约的能源量,为分析计算畜禽养殖场大中型沼气工程能源效益和经济效益提供了方法和案例.     

Prospects for expanded utilization of biogas in Germany

The prospects for expanded utilization of biogas systems in German was analysed, by identifying the operational and policy factors affecting the complete chain of processes from implementation process for biogas plants, through to biogas production and utilization. It was found that the Renewable Energies Act (EEG) and energy tax reliefs provide bases for the support of expanded utilization. Upgrading of biogas to natural gas quality for utilization in the transportation sector was arguably the most promising technology that could support rapid utilization expansion. Sustainable deployment of biogas systems in light of the unstable feedstock prices and availability, and the need for subsidy-free operation in the long term requires; enhancement of feedstock flexibility and quality characteristics to maximise gas yield, and optimisation of the anaerobic digestion process management. Assessment of energy balance and potential environmental impacts of the integrated process chain provides a holistic assessment of sustainability. The results also support the development and foster of policies and framework for development of biogas as environmentally friendly energy resource, among a mix of renewable energy sources, hence, compete favourably with fossil fuels to enhance the prospects for expanded utilization.     

中德沼气工程此较

在考察中国和德国沼气工程现场及查阅大量文献报道的基础上,就巾德沼气工程发展现状、政策法规、技术进展(包括发酵原料、发酵工艺、沼气净化、沼渣沼液利用以及沼气发电)等方面进行了比较,提出了中国农业废弃物沼气工程的差距以及改进的措施.     

Competitive and risk-adequate auction bids for onshore wind projects in Germany

In recent years, auction mechanisms have gained in significance in the context of renewable energy deployment. An increasing number of countries have adopted auctions for the allocation of permits and financial support for renewable energy projects, thereby increasing competition among project developers. As a result, profit margins have decreased significantly while sensitivity to risks and uncertainty has increased. The adequate quantification of bid prices is a key challenge. We present a modeling approach to determine competitive and risk-adequate auction bids. The contribution of this paper is an improved method for quantifying marginal cost, which is the minimum sales price per unit of electricity through which the investment criteria of all project stakeholders are fulfilled. In our financial model, the risk-adequateness is determined through the investment criteria of equity investors by means of the adjusted present value, and those of debt investors by means of the debt service cover ratio, through Monte Carlo simulations. The resulting marginal cost serve as the starting point for strategic bidding optimization, regardless of the pricing rule in the contemplated auction design. To demonstrate the integrability of our mathematical model with strategic bidding optimization, we check its applicability in a case study, which shows how a German project developer should bid to realize an onshore wind farm project. We show that our model enables the quantification of bid prices that are both competitive and risk-adequate.     

北京大中型沼气工程冬季运行存在的问题及对策

文章对目前北京市大中型沼气工程冬季运行存在的问题进行了分析,分别从工程的设计、施工和运行管理3个方面提出了相应的解决对策,以期为大中型沼气工程冬季的正常运行提供参考,从而最大程度实现沼气工程的经济效益、环境效益和社会效益。     

The status and future of methane destruction projects in Mexico

Of the Clean Development Mechanism projects that exist in Mexico, methane destruction from hog farms dominates the landscape with 56% of the projects developed and 49% of the certified emission reductions that will be generated within the country by 2012. These biodigesters, however, have experienced many technical difficulties that place their future viability and continued development in question. Because of these challenges, future methane capture in the country may focus around other agro industries or landfills.     

Current status of hydrogen energy

This paper examines the present status of hydrogen energy and looks at different approaches for technological advances. Some of the new developments in the progress of the recent directions of world hydrogen production and utilization are reported.The aim of this article is to inform the reader of hydrogen technology, economics, environmental impact, special system applications, hydrogen energy status around the world at the end of the 20 century as well as hydrogen organizations, associations, projects, periodicals and conferences.     

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。     

关于沼气发电设备生产行业发展情况的调研报告

随着《可再生能源法》及其各项配套法规、实施细则相继颁布实施,将进一步促进我国沼气发电产业的大规模发展.鉴于沼气产业发展的需要,中国沼气学会于2006年3月初组织有关专家赴山东省东营、潍坊和济南3市,分别对我国目前从事沼气发电设备研发和生产的胜利油田动力机械有限公司、潍柴动力股份有限公司和济南柴油机股份有限公司等企业进行了专题调研,并就这些企业在沼气发电设备制造的技术研发、生产能力、质量保障体系、市场营销和售后服务能力等方面情况开展了实地考察。     

The impact of plant size and location on profitability of biogas plants in Germany under consideration of processing digestates

The production of bioenergy is considered to be a promising energy source for a sustainable energy mix and it is politically promoted in many countries. With the exception of Brazilian ethanol, bioenergy is not competitive with fossil energy sources, and therefore needs to be subsidised. Several types of bioenergy are based on bulky raw biomass with high per unit transport costs, importantly impacting on the plant's production costs and profitability. In addition, considerable quantities of digestates are released, causing disposal costs. Various studies in the past aimed primarily at analysing transport costs of inputs. In this paper we focus on disposal costs of fermentation digestates from biogas production in Germany and analyse different processing techniques and their impact on profitability for three plant size in three case study areas.Our results show that especially in regions with only a small amount of agricultural land and a large heterogeneity in its agricultural area, processing of digestates increases the profitability of biogas production. The same accounts for regions with high livestock density, where the area needed for disposal is comparatively large. The cost efficiency is enforced by a high share of animal excrements on input and the biogas plant size.