太阳能-空气源热泵耦合式沼气池加温系统设计

针对8 m3沼气发酵池设计了一套空气源热泵-太阳能耦合式加温系统,可以根据不同天气切换运行太阳能、太阳能空气源热泵和空气源热泵3种热源模式,以满足沼气池内的加温需求。计算了沼气池加温系统的热负荷,将该系统与电热膜加温系统和地源热泵系统进行了比较,可以分别增加投资效益净现值11866.9元和4726.7元,多投资部分的投资回收期分别为8年和4年。可见,对于小型沼气池工程,采用空气源热泵辅助太阳能热水系统,从节能性与经济性来讲,是一种适宜推广的热源形式。     

太阳能沼气池

我国农村户用沼气池大都采用常温发酵.由于发酵温度随四季气温的变化而变化,所以冬春季节沼气池产气率不足的问题,是目前农村普及沼气技术亟待解决的问题之一.详述了太阳能沼气池的结构和工作原理,并通过经济分析,说明将太阳能热水供给技术与沼气池技术改造相结合,利用太阳能热水循环技术提高沼气池冬季产气率,降低沼气池一年四季供气量的波动范围,经济效益显著·太阳能沼气池实现了炊事用能,照明、冬季采暖等沼气供给和太阳能热水供应一体化,是解决农村能源紧缺问题,改善农民生活、生产条件,促进农业产业结构调整,保护农村生态环境,繁荣农村经济,增强农村可持续发展能力的重要举措.     

农村户用沼气池技术改造

简述了农村户用沼气池的结构和产气条件,针对沼气技术在普及推广过程中存在的问题,提出了提高沼气池发酵温度的基本措施和管理要求,重点介绍了活塞式出渣、搅拌器的结构、功能和工作原理.进料方便,出渣难,池内浮渣容易结壳,且难于破碎,所以发酵原料的利用率不高,沼气池产气率偏低,严重影响了沼气技术在农村的普及推广.活塞式出渣、搅拌器,具有搅拌和出渣双重功能,利用这项技术改造措施,不仅可以大大降低劳动强度,缩短出渣时间,减少液面结壳机会,提高沼气池产气率,还可以延长沼气池使用寿命,为提高农民生活质量,推动农业、家庭副业发展发挥巨大作用.     

常温自循环沼气池的建造与效益

常温自循环沼气池,是村镇建设中用于专业户的配套设施,是在推广农村粪草分离式沼气池的基础上研究改进的。这种池型结构考虑到农村专业户发展沼气的具体条件和投资效益,能提高产气量并使进出料简化与集中供气,为畜禽专业户和农牧场(菜篮子工程)提供了一种结构合理、料源充足、工艺先进、自动进出料、安全方便、改善环境污染的新池型。     

沼气日常管理中存在的问题及解决方法

<正>近年来,国家对农村新能源的开发和建设极其重视,并为此投入大量的建设资金,使全国各地区农村沼气建设取得了丰硕的成果。现将沼气日常管理方法以及存在的的问题介绍如下。一、日常管理加入沼气池的发酵原料,经沼气细菌发酵产生沼气,原料的营养成分会逐渐被消耗,为保证沼气细菌有充足的食物,使沼气池正常产气,就要不断地补充新原料,做到勤加料、勤出料。沼气池加新料一般要在产气量高峰没有下降以前进行,即启动后20 d,最迟不得超过30 d。畜禽舍和厕所     

混合纤维水泥沼气浮罩使用效果浅析

一、概况我市十余年来,已建成沼气池一万余只。沼气在本市广大农村生活用燃中占有一定的比例,沼气的推广也有较好的群众基础,广大农户早已养成了良好的管理和使用沼气的习惯。池的形状也在不断更新,由最早的水压式发展到闸塞自流沼气池。本市在8～85年协助浙江省沼科所搞了自流出料新池型的试验,命名为闸塞沼气池,此池型通过了国家沼办鉴定,目前已在全国推广应用。在病态池、老池的改造中也取得了一定的成绩。随着农村形势的变化,沼气建设应结合     

有机玻璃钢沼气池池壁材料机械和传热性能研究

传统的玻璃钢沼气池因不能有效保持发酵罐内温度而影响了在低温条件下的沼气发酵产气性能。因此研究沼气池壁材料的机械和热学性能能有助于指导新型绝热沼气反应池的设计,利用发酵过程代谢产热以提高沼气的产气率。实验主要研究了以有机玻璃钢为主要骨架的沼气池池体材料的力学和热学性能。研究结构表明,传统的玻璃钢沼气池池体材料具有较高的机械强度和一定的保温性能;同时该有机玻璃钢材料具有一定的耐酸性,而耐碱性较差。材料尚需改进以进一步增强其绝热性能以满足沼气池内微生物菌种发酵产气所需的能量要求。     

研制超低压沼气燃具的技术经验

一、低压沼气燃具研制的必要性 1.提高水压式沼气池的使用效率 中国目前约有700万农户用上沼气,其中95％以上为水压式沼气池。水压式沼气池是利用连通管的原理设计的,其气箱容积随产气量的增加而逐渐增加,水压箱的水面也及时不断上升,气箱与水压箱液面高度之差即为沼气池的压力。农村家用沼气池的设计压力一般为400～800mmH_2O(3922～7844Pa),经过管道及节门的阻力损失后,其燃具前压力降至200～600mmH_2O(1961～588     

离子液体提取茶叶中咖啡因的工艺研究

以离子液体[HSO3-pmim]+[HSO4]-为提取剂,以咖啡因的产量为评价指标,从茶叶中提取咖啡因。通过单因素实验考察了料液比、提取时间、提取温度、离子液体浓度对咖啡因产量的影响。实验结果表明,料液比、提取时间、提取温度、离子液体浓度对咖啡因的产量有较大影响,当料液比为1∶25,提取温度为95℃,提取时间为180 min,离子液体浓度为80%时,咖啡因产量最高为108.6 mg。该方法简便,易于操作,对环境无污染,同时产品产量高、纯度好。     

细谈农村户用沼气池技术

<正>农村户用沼气,就是在广大农村以户为单位建设的沼气池。在我国,利用推广沼气的历史悠久,最早源于二十世纪三十年代初罗国瑞等人创造发明并获得专利的水压式沼气池。历经几十年的反复实践,沼气池实用技术得以提高和不断扩大,特别是近些年来,小型高效沼气池的研制与推广,使我国农村沼气技术水平和发展速度均居于世界领先地位。凭着节约能源、适用卫生、综合利用效益等几大优势,沼气池建设在我省广大农村呈现了蓬勃发展的良好态势,给千家万户带来     

太阳能辅助加热户用沼气池

户用沼气是我国农村能源的重要组成部分.本文针对北方寒冷地区冬季气温低、沼气产气少、利用率低等问题,设计了保温沼气池并结合家用太阳能热水器,提出了太阳能辅助加热户用沼气池系统.利用现场收集的运行数据,分析了该系统的实用性.     

Mesophilic and thermophilic anaerobic digestion of faecal sludge in a pilot plant digester

In many developing countries, the sewage consisting of faecal sludge is discharged untreated into rivers, lakes and coastal areas. This poses a health hazard and a risk to the ecosystem, and wastes a resource which could produce sustainable energy. This paper reports results from an anaerobic digester of 1000L used for digestion of faecal waste at mesophilic and thermophilic conditions. The specific biogas production rate from faecal sludge was in the range of 0.06–0.12 m³/(kg DM.d) at mesophilic conditions at NTP (Normal Temperature & Pressure i.e. 25 °C and 1 atm. Pressure) and 0.1–0.21 m³/(kg DM.d) at thermophilic conditions calculated at NTP. The number of toilet users affects the biogas production with changes in the organic loading rate. The results showed 97% reductionin chemical oxygen demand and 90% reduction in biological oxygen demand of anaerobic digester discharge water as compared to inlet substrate values.     

户用沼气池的建造技术

介绍了家用沼气池的类型,提出了家用沼气池的设计依据,从备料、放线、池坑开挖和浇筑等方面阐述了户用沼气池施工技术,以积累沼气池建造经验,促进沼气科学技术的发展和应用。     

GISCOD: General Integrated Solid Waste Co-Digestion model

This paper views waste as a resource and anaerobic digestion (AD) as an established biological process for waste treatment, methane production and energy generation. A powerful simulation tool was developed for the optimization and the assessment of co-digestion of any combination of solid waste streams. Optimization was aimed to determine the optimal ratio between different waste streams and hydraulic retention time by changing the digester feed rates to maximize the biogas production rate. Different model nodes based on the ADM1 were integrated and implemented on the Matlab-Simulink^® simulation platform. Transformer model nodes were developed to generate detailed input for ADM1, estimating the particulate waste fractions of carbohydrates, proteins, lipids and inerts. Hydrolysis nodes were modeled separately for each waste stream. The fluxes from the hydrolysis nodes were combined and generated a detailed input vector to the ADM1. The integrated model was applied to a co-digestion case study of diluted dairy manure and kitchen wastes. The integrated model demonstrated reliable results in terms of calibration and optimization of this case study. The hydrolysis kinetics were calibrated for each waste fraction, and led to accurate simulation results of the process and prediction of the biogas production. The optimization simulated 200,000 days of virtual experimental time in 8 h and determined the feedstock ratio and retention time to set the digester operation for maximum biogas production rate.     

Effect of co-digestion agricultural-industrial residues: various slurry temperatures

The main objective of this study is to investigate the effect of co-digestion using industrial-agro waste and operating temperature of digester slurry to enhance the biogas and methane yield. The anaerobic digestion process is carried out by using a floating dome type bio-digester with the capacity of 1?m³. The co-digestion of press mud and rice straw with the ratio of 1:1, slurry temperature mesophilic range of (30–40°C) and thermophilic raange of (41–55°C) is used in this study. The maximum generation of daily biogas and weekly methane yield obtained were about 190?L/day and 55% in the case of the thermophilic condition. The lowest generation of daily biogas and weekly methane yield obtained were about 130?L/day and 33% in the case of mesophilic condition. The 10 percentage of cow dung is used as an inoculum of the digester and 30 days of hydro retention time for both the temperature ranges. The methane and biogas yield is at its peak and there was a faster hydro retention time in thermophilic range temperature at 52°C.     

Investigations on a pilot-plant contact digester for the treatment of a dilute urban waste

A pilot-plant contact digester treating an urban waste which approximated the BOD strength of domestic sewage was operated and the effect of loading and temperature, in the range 20° – 27°C, on performance was evaluated. Acclimatization of the digester to full loading is described and the upper limit of loading was determined. The problem of separation of sludge is also discussed.     

Continuous Process anaerobic biogas production from poultry wastes

Energy demand in rural areas of developing countries has driven researchers towards harnessing energy sources available to them. One of those recognised sources available in rural areas is waste organic materials. This paper examines the continous process method of biogas production from poultry wastes at various conditions under anaerobic digestion. Biogas technology enables rural dwellers to obtain cheap, high-grade fuel as well as organic fertiliser through the resources available to them locally. A biogas programme helps to solve environmental problems arising from the disposal of organic waste materials. The treatment of sewage protects water supply. Biogas technology helps to conserve foreign exchange for energy importing countries. The test results show that gas production rates were higher at controlled elevated temperature compared to the production rates at ambient conditions. It indicates that bacteria are more active at high temperatures. The digested effluent sludge is a high quality organic fertiliser, which is richer than inorganic manure, and it fixes well in the soil.     

焦炉烟道废气余热的利用

利用焦炉烟道废气余热,在焦炉废气烟囱底部增加一台换热器,把地下冷水加热到70℃,用于职工洗浴。论述了换热器的计算、结构设计、施工安装,改造后的洗浴热水供应流程及经济效益。     

复合蓄热式水箱的设计及蓄放热研究

设计了一种具有辅助电加热和均流孔板的水/相变材料复合蓄热式水箱,该水箱以封装有复合八水氢氧化钡的相变蓄热球作为储热单元。理论分析了相变蓄热球应用于复合蓄热式水箱中的可行性,实验研究了水箱中有无相变蓄热球、恒定流量下的直接和恒温蓄放热特性,结果表明:均流孔板的应用,可使冷热水在水箱底部均匀混合,使高温热水出水量达到最大;在热水出水流量为3.3 L/min时,添加60个相变蓄热球的复合蓄热式水箱比纯水箱可多制得10 L 60℃以上的热水;在热水出水流量为1.6 L/min时,添加120个相变蓄热球的复合蓄热式水箱比纯水箱可多制得40 L 40℃的恒温热水。     

Comparative evaluation of batch and continuous process biogas production from animal wastes

The production of biogas, an alternative source of energy from animal wastes, was investigated in the laboratory scale using the simple single-state digesters. In this study, a comparison between two feed processes, a batch feeding process and a continuous feeding process, both within mesophilic temperature ranges was carried out. The digesters were fed with mixture of cow dung and poultry droppings and operated at ambient temperature of 30°C as baseline and temperatures of 32?45°C for 30 days. In this study, the optimum temperature for biogas production from the blends of the animal wastes was determined as controlled heat was supplied to the digester. Results obtained indicate maximum biogas yield of 3.603 litres from the digestion of the animal wastes at temperature of 370°C in the continuous process while maximum biogas yield of 2.685 litres was obtained at temperature of 400°C for the batch process.