首页> 外文OA文献 >Sustainable Energy for New Zealand Dairy Farms by Anaerobic Digestion of Dairy Farm Effluent
【2h】

Sustainable Energy for New Zealand Dairy Farms by Anaerobic Digestion of Dairy Farm Effluent

机译:奶牛场废水厌氧消化为新西兰奶牛场提供可持续能源

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务,本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文,但由于OA文献来源多样且变更频繁,仍可能出现获取不到、文献不完整或与标题不符等情况,如果获取不到我们将提供退款服务。请知悉。

摘要

This study evaluated the economic feasibility and environmental impact of using a bio-digester to produce methane for energy production from a New Zealand conventional dairy farm.Parameters effecting the bio-methanation process are examined. Analytical procedures have been carried out to determine favorable conditions for enhanced biogas production. These were: 1) pH, 2) Temperature, 3) Total solids and Total Volatile solids, 4) Gas volume and 5) Gas analysis.Using locally supplied dairy shed effluent, it was found that 1 L reactors had peak gas production over 15 days, after which pH dropped and gas production dropped. Optimal pH was 7 and maximum gas production was 1.25 L/L reactor.A three stage digester was set up and run for 62 days with a maximum cumulative gas production of 21.3 L, 11.7 L and 6.6 L in the three reactors. Total volumetric methane production was 0.09 m3/kgVS/day 0.06 m3/kgVS/day and 0.07 m3/kgVS/day respectively from reactors 7, 8 and 9. The reactors produced biogas with an average composition of 74 % methane (CH4) and 25% carbon-dioxide (CO2). A typical digester would produce 65-70% CH4.1 kg of methane produces 4.66 kWh electricity and 5.72 kWh of heat, a typical farm of 250 cows would produce 548 kWh/day electricity and 665 kWh/day heat from using methane captured in the anaerobic digesters using dairy shed effluent. A typical 250 cow farm consumes 1285 kWh/day total energy 40% is from heat and rest is electricity. So by having installed plug-flow anaerobic digesters it could potentially meet 130% of total energy needs and 113% of total energy needs by using a three stage mesophilic digester.A life cycle assessment was carried out for a typical New Zealand farm. Methane emissions from enteric fermentation, excreta, manure and farm dairy effluent irrigation and storage ponds contribute to 60% of the total greenhouse gas (GHG) emissions of a farm. Management of dairy shed effluent will only reduce GHG emissions by 1.8%. In addition, spray irrigation will impact on GHG emissions due increased moisture, C and N content, increasing N2O emissions. Hence from an environmental sustainability point of view, collecting and digesting diary shed effluent will have little significant impact on overall GHG emissions. Therefore, collecting and digesting dairy effluent is only of value if it results in economic benefits for the farm.An economic analysis was conducted on installing a digester system. The anaerobic digester systems for 250 cow farm would have a capital cost of $107,745 per year, an operating cost of $134,828 per year, and generate revenue of $132,819 per year, but would not be able to pay back the capital cost. For a 250 cow farm a plug flow digester would have a capital cost of $95,658 per year, operating cost $127,018 per year, generate revenue $194,722 per year, and the resulting payback period is 2 years. A three stage digester for a 250 cow farm would have a capital cost of $259,608 an operating cost of $215,920 per year, generate revenue of $296,389 per year, a payback period of 3 years. But for a large farm size of 600-1000 cows therefore a multi stage digester would be worthwhile. For large dairy farms, CH4 capture with energy recovery can already be cost effective based on the energy value alone.
机译:这项研究评估了使用生物消化器从新西兰常规奶牛场生产甲烷用于能源生产的经济可行性和环境影响,研究了影响生物甲烷化过程的参数。已经进行了分析程序以确定增加沼气生产的有利条件。它们是:1)pH,2)温度,3)总固体和总挥发性固体,4)气体量和5)气体分析使用本地供应的奶牛场废水,发现1 L反应器的产气峰值超过15几天后,pH下降,产气量下降。最佳pH值为7,最大产气量为1.25 L / L反应器。建立了一个三级消化器,运行62天,三个反应器中的最大累积产气量分别为21.3 L,11.7 L和6.6 L.反应器7、8和9的甲烷总生产量分别为0.09 m3 / kgVS /天0.06 m3 / kgVS /天和0.07 m3 / kgVS /天。这些反应器生产的沼气的平均成分为74%甲烷(CH4)和25 %的二氧化碳(CO2)。一个典型的沼气池将产生65-70%CH4.1公斤的甲烷,产生4.66 kWh的电力和5.72 kWh的热量,一个拥有250头奶牛的典型农场将利用捕获在甲烷中的甲烷来产生548 kWh /天的电力和665 kWh /天的热量。厌氧消化池使用奶牛场废水。一个典型的250头奶牛场每天消耗1285千瓦时,总热量的40%来自热能,其余是电力。因此,通过安装活塞流厌氧消化池,使用三级中温消化池可以满足130%的总能源需求和113%的总能源需求。对一个典型的新西兰农场进行了生命周期评估。肠内发酵,排泄物,粪便和农场奶类污水灌溉和储存池产生的甲烷排放占农场总温室气体(GHG)排放的60%。乳牛粪废水的管理只会减少1.8%的温室气体排放。此外,由于水分,碳和氮含量增加,N2O排放增加,喷灌将影响温室气体排放。因此,从环境可持续性的角度来看,收集和消化日记流下的废水不会对整体温室气体排放产生重大影响。因此,收集和消化乳制品废水只有在为农场带来经济利益的情况下才有价值。对蒸煮器系统的安装进行了经济分析。 250个奶牛场的厌氧消化系统每年的资本成本为107,745美元,每年的运营成本为134,828美元,每年产生的收入为132,819美元,但无法偿还资本成本。对于一个250头奶牛场来说,塞流式消化器每年的资本成本为95,658美元,每年的运营成本为127,018美元,每年的收入为194,722美元,因此,投资回收期为2年。一个250头奶牛场的三级沼气池的资本成本为259,608美元,每年的运营成本为215,920美元,每年的收入为296,389美元,投资回收期为3年。但是,对于拥有600-1000头奶牛的大型农场而言,因此多级消化池将是值得的。对于大型奶牛场而言,仅凭能量值就可以通过能量回收来捕获CH4。

著录项

  • 作者

    Yenamandra Aparna;

  • 作者单位
  • 年度 2016
  • 总页数
  • 原文格式 PDF
  • 正文语种 en
  • 中图分类

相似文献

  • 外文文献
  • 中文文献
  • 专利

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号