翻訳と辞書 |
Landfill gas utilization : ウィキペディア英語版 | Landfill gas utilization
Landfill gas utilization is a process of gathering, processing, and treating the methane gas emitted from decomposing garbage to produce electricity, heat, fuels, and various chemical compounds. The number of landfill gas projects, which convert the gas into power, went from 399 in 2005 to 519 in 2009 in the United Kingdom, according to the Environment Agency. These projects are popular because they control energy costs and reduce greenhouse gas emissions. These projects collect the methane gas and treat it, so it can be used for electricity or upgraded to pipeline-grade gas. These projects power homes, buildings, and vehicles. == Generation ==
Landfill gas (LFG) is generated through the degradation of municipal solid waste (MSW) by microorganisms. The quality (higher percent methane gases signify higher qualities) of the gas is highly dependent on the composition of the waste, presence of oxygen, temperature, physical geometry and time elapsed since waste disposal.〔(DoE Report CWM039A+B/92 ) Young, A. (1992)〕 Aerobic conditions, presence of oxygen, leads to predominately emissions. In anaerobic conditions, as is typical of landfills, methane and are produced in equal amounts. Methane () is the important component of landfill gas as it has a calorific value of 33.95 MJ/Nm^3 which gives rise to energy generation benefits.〔Scottish Environment Protection Agency. Guidance on Landfill Gas Flaring. November 2002. Web. .〕 The amount of methane that is produced varies significantly based on composition of the waste. Most of the methane produced in MSW landfills is derived from food waste, composite paper, and corrugated cardboard which comprise 19.4 ± 5.5%, 21.9 ± 5.2%, and 20.9 ± 7.1% respectively on average of MSW landfills in the United States.〔Staley, Bryan, Morton Barlaz, and Morton Barlaz. "Composition of Municipal Solid Waste in the United States and Implications for Carbon Sequestration and Methane Yield." Journal of Environmental Engineering, 135.10 (2009): 901-909.〕 The rate of landfill gas production varies with the age of the landfill. There are 4 common phases that a section of a MSW landfill undergoes after placement. Typically, in a large landfill, different areas of the site will be at different stages simultaneously. The landfill gas production rate will reach a maximum at around 5 years and start to decline.〔Whittington, H. "Electricity Generation: Options for Reduction in Carbon Emissions." , 360.1797 (2002): 1653-1668. .〕 Landfill gas follows first-order kinetic decay after decline begins with a k-value ranging 0.02 yr-1 for arid conditions and 0.065 yr-1 for wet conditions.〔U.S. Environmental Protection Agency. "Landfill Gas Modeling." LFG Energy Project Development Handbook. 30 January 2009. Web. 26 November 2009. .〕 Landfill Methane Outreach Program (LMOP) provides first order decay model to aid in the determination of landfill gas production named LandGEM (Landfill Gas Emissions Model).〔 Typically, gas extraction rates from a municipal solid waste (MSW) landfill range from 25 to 10000 m³/h where Landfill sites typically range from 100,000 m³ to 10 million m³.〔 MSW landfill gas typically has roughly 45 to 60% methane and 40 to 60% carbon dioxide.〔U.S. Environmental Protection Agency. "Landfill Gas Energy Basics." LFG Energy Project Development Handbook. 16 February 2009. Web. 26 November 2009. .〕 There are many other minor components that comprises roughly 1% which includes , , , , non-methane volatile organic compounds (NMVOCs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), etc. All of the aforementioned agents are harmful to human health at high doses.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Landfill gas utilization」の詳細全文を読む
スポンサード リンク
翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|