美国天然气系统存在泄露隐患-凯发k8官网

美国天然气系统存在泄露隐患
文章来源:未知 文章作者:enread 发布时间:2014-02-15 07:11 字体: [ ] 
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the first thorough comparison of evidence for natural gas system leaks confirms that organizations including the environmental protection agency (epa) have underestimated u.s. 1 3 generally, as well as those from the natural gas industry specifically. natural gas consists predominantly of methane. even small leaks from the natural gas system are important because methane is a 4 greenhouse gas -- about 30 times more potent than carbon dioxide. a study, "methane 5 from north american natural gas systems," published in the feb. 14 issue of the journal science, synthesizes diverse findings from more than 200 studies ranging in scope from local gas processing plants to total emissions from the united states and canada.
 
"people who go out and actually measure methane pretty consistently find more emissions than we expect," said the lead author of the new analysis, adam brandt, an assistant professor of energy resources engineering at stanford university. "6 tests covering the entire country indicate emissions around 50 percent more than epa estimates," said brandt. "and that's a moderate estimate."
 
the standard approach to estimating total methane emissions is to multiply the amount of methane thought to be emitted by a particular kind of source, such as leaks at natural gas processing plants or 7(嗳气) cattle, by the number of that source type in a region or country. the products are then totaled to estimate all emissions. the epa does not include natural methane sources, like wetlands and 8 9.
 
the national natural gas 10 has a combination of 11 leaks, often for safety purposes, and unintentional emissions, like faulty valves and cracks in 12. in the united states, the 2 rates of particular gas industry 13 -- from wells to burner tips -- were established by the epa in the 1990s.
 
since then, many studies have tested gas industry components to determine whether the epa's emission rates are accurate, and a majority of these have found the epa's rates too low. the new analysis does not try to attribute percentages of the excess emissions to natural gas, oil, coal, agriculture, landfills, etc., because emission rates for most sources are so uncertain.
 
several other studies have used airplanes and towers to measure actual methane in the air, so as to test total estimated emissions. the new analysis, which is authored by researchers from seven universities, several national laboratories and federal government bodies, and other organizations, found these atmospheric studies covering very large areas consistently indicate total u.s. methane emissions of about 25 to 75 percent higher than the epa estimate.
 
some of the difference is accounted for by the epa's focus on emissions caused by human activity. the epa excludes natural methane sources like geologic seeps and wetlands, which atmospheric samples unavoidably include. the epa likewise does not include some emissions caused by human activity, such as abandoned oil and gas wells, because the amounts of associated methane are unknown.
 
however, the analysis also finds that some recent studies showing very high methane emissions in regions with considerable natural gas infrastructure are not representative of the entire gas system. "if these studies were representative of even 25 percent of the natural gas industry, then that would account for almost all the excess methane 14 in continental-scale studies," said a co-author of the study, eric kort, an atmospheric science professor at the university of michigan. "observations have shown this to be unlikely."


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1 t1eyx     
n.甲烷,沼气
参考例句:
  • the blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
  • methane may have extraterrestrial significance.甲烷具有星际意义。
2 vjnz4     
n.发出物,散发物;发出,散发
参考例句:
  • rigorous measures will be taken to reduce the total pollutant emission.采取严格有力措施,降低污染物排放总量。
  • finally,the way to effectively control particulate emission is pointed out.最后,指出有效降低颗粒排放的方向。
3 1a87f8769eb755734e056efecb5e2da9     
排放物( emission的名词复数 ); 散发物(尤指气体)
参考例句:
  • most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
  • dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。
4 c1uzk     
adj.强有力的,有权势的;有效力的
参考例句:
  • the medicine had a potent effect on your disease.这药物对你的病疗效很大。
  • we must account of his potent influence.我们必须考虑他的强有力的影响。
5 h1dxq     
n.漏,泄漏;泄漏物;漏出量
参考例句:
  • large areas of land have been contaminated by the leakage from the nuclear reactor.大片地区都被核反应堆的泄漏物污染了。
  • the continuing leakage is the result of the long crack in the pipe.这根管子上的那一条裂缝致使渗漏不断。
6 6eayr     
adj.大气的,空气的;大气层的;大气所引起的
参考例句:
  • sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
  • clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。
7 belching     
n. 喷出,打嗝 动词belch的现在分词形式
参考例句:
  • the tartars employed another weapon, the so-called chinese dragon belching fire. 鞑靼人使用了另一种武器,所谓中国龙喷火器。
  • billows of smoke were belching from the chimney. 巨浪似的烟正从烟囱里喷出来。
8 dg3x9     
adj.地质的
参考例句:
  • the red sea is a geologic continuation of the valley.红海就是一个峡谷在地质上的继续发展。
  • delineation of channels is the first step of geologic evaluation.勾划河道的轮廓是地质解译的第一步。
9 074f5ef8e0953325ce81f208b2e4cecb     
n.(液体)渗( seep的名词复数 );渗透;渗出;漏出v.(液体)渗( seep的第三人称单数 );渗透;渗出;漏出
参考例句:
  • water seeps through sand. 水渗入沙中。 来自《现代汉英综合大词典》
  • water seeps out of the wall. 水从墙里沁出。 来自《现代汉英综合大词典》
10 ubbz5     
n.下部构造,下部组织,基础结构,基础设施
参考例句:
  • we should step up the development of infrastructure for research.加强科学基础设施建设。
  • we should strengthen cultural infrastructure and boost various types of popular culture.加强文化基础设施建设,发展各类群众文化。
11 65axb     
adj.故意的,有意(识)的
参考例句:
  • let me assure you that it was not intentional.我向你保证那不是故意的。
  • his insult was intentional.他的侮辱是有意的。
12 2bee8f0b9bb303b1f1a466fd43666db3     
管道( pipeline的名词复数 ); 输油管道; 在考虑(或规划、准备) 中; 在酿中
参考例句:
  • the oil is carried to the oil refinery by pipelines. 石油通过输油管输送到炼油厂。
  • the oil carried in pipelines. 石油用管道输送。
13 4725dcf446a342f1473a8228e42dfa48     
(机器、设备等的)构成要素,零件,成分; 成分( component的名词复数 ); [物理化学]组分; [数学]分量; (混合物的)组成部分
参考例句:
  • the components of a machine 机器部件
  • our chemistry teacher often reduces a compound to its components in lab. 在实验室中化学老师常把化合物分解为各种成分。
14 5n4zxc     
adj.著名的,知名的
参考例句:
  • the local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
  • jim is noted for arriving late for work.吉姆上班迟到出了名。
tag标签: plants gas methane
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