育路教育網特別為您搜集整理2011年考研英語輔導資料。希望對大家有所幫助,取得一個好的成績! Coal-fired Power Plants The invention of the incandescent light bulb by Thomas A. Edison in 1879 created a demand for a cheap, readily available fuel with which to generate large amounts of electric power. Coal seemed to fit the bill, and it fueled the earliest power stations (which were set up at the end of the nineteenth century by Edison himself)。 As more power plants were constructed throughout the country, the reliance on coal increased. Since the First World War, coal-fired power plants have accounted for about half of the electricity produced in the United States each year. In 1986 such plants had a combined generating capacity of 289, 000 megawatts and consumed 83 percent of the nearly 900 million tons of coal mined in the country that year. Given the uncertainty in the future growth of nuclear power and in the supply of oil and natural gas, coal-fired power plants could well provide up to 70 percent of the electric power in the United States by the end of the century. Yet, in spite of the fact that coal has long been a source of electricity and may remain one for many years (coal represents about 80 percent of United States fossil-fuel reserves), it has actually never been the most desirable fossil fuel for power plants. Coal contains less energy per unit of weight than natural gas or oil; it is difficult to transport, and it is associated with a host of environmental issues, among them acid rain. Since the late 1960's problems of emission control and waste disposal have sharply reduced the appeal of coal-fired power plants. The cost of ameliorating these environmental problems along with the rising cost of building a facility as large and complex as a coal-fired power plant, have also made such plants less attractive from a purely economic perspective. Changes in the technological base of coal-fired power plants could restore their attractiveness, however. Whereas some of these changes are evolutionary and are intended mainly to increase the productivity of existing plants, completely new technologies for burning coal cleanly are also being developed. 全文翻譯:火力發電廠 托馬斯。愛迪生 1879 年發明的白熾燈導致對便宜、易得、可生產大量電能 的燃料的需求。 煤似乎符合這個要求,并成為第一批電廠的燃料(正是愛迪生本人在 19 世 紀末建造了第一批電廠)。 全國到處興建電廠時,對煤的依賴加深了。 自第一次世界大戰 以來,美國每年約有一半的電力是以煤為燃料的電廠提供的。 1986 年這些電廠的總發電能 力達到 28,900 千瓦并且消耗了當年全國開采的九億噸煤的 83%. 考慮到核能發展以及石 油、天然氣供應中的不確定因素,到本世紀末,火力發電廠仍可能為美國提供多達 70%的 電力。 然而,盡管煤長期以來一直是電力的原料之一并且可能會繼續如此(煤占美國化石燃 料儲量的 80%),它卻不是電廠的理想燃料。 煤的單位能量含量低于石油和天然氣,而且會 導致包括酸雨在內的一系列環境問題。 從 1960 年以來,排放控制和垃圾處理的問題極大地削弱了燃煤電廠的魅力。 由于減輕這些環境問題需要大量資金,而且建造龐大復雜的燃煤 電廠的費用不斷上漲,也使得這些電廠從經濟角度上不具備吸引力。 改變火力發電廠的基 礎技術卻可能恢復它們的吸引力。 雖然某些技術改進是漸進的,其目的只是提高現有電廠 的生產率,但人們正在開發全新的清潔燃煤的技術。 |
考研最新熱貼: |
【責任編輯:育路編輯 糾錯】 |
|
閱讀上一篇:2011年考研優美英語作文背誦041 |
|
閱讀下一篇:2011年考研優美英語作文背誦044 |
|
|
報考直通車 |
·【訪談視頻】2012考研英語高分復習方法——宏 |
·【訪談實錄】2012年考研英語高分復習方法 |
·【訪談實錄】2011年考研英語真題點評 |
·2011年考研英語科目試題及答案解析匯總 |
·恩波:2011考研英語大小作文真題及范文 |
·考研教育網:2011年考研英語一大作文范文 |
·2011年考研英語二沖刺自測題 |
·2011年考研英語二沖刺自測題下篇 |
·2011年考研英語二沖刺自測題中篇 |
·2011年考研英語二沖刺自測題上篇 |
·2011年考研英語點題班試題(第一套) |
·2011年考研英語全真沖刺模擬試題及答案匯總 |