首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
Petroleum Petroleum, like coal, is found in sedimentary rocks, and was probably formed from long-dead living organisms. The r
Petroleum Petroleum, like coal, is found in sedimentary rocks, and was probably formed from long-dead living organisms. The r
admin
2012-01-05
57
问题
Petroleum
Petroleum, like coal, is found in sedimentary rocks, and was probably formed from long-dead living organisms. The rocks in which it is found are almost always of ocean origin and the petroleum-forming organisms must have been ocean creatures rather than trees.
Instead of originating in accumulating woody matter, petroleum may be the product of the accumulating fatty matter of ocean organisms such as plankton, the myriads of single-celled creatures that float in the surface layers of the ocean.
The fat of living organisms consists of atom combinations that are chiefly made up of carbon and hydrogen atoms. It does not take much in the way of chemical change to turn that into petroleum. It is only necessary that the organisms settle down into the ooze underlying shallow arms of the ocean under conditions of oxygen shortage. Instead of decomposing and decaying, the fat accumulates, is trapped under further layers of ooze, undergoes minor rearrangements of atoms, and finally is petroleum.
Petroleum is lighter than water and, being liquid, bends to ooze upward through the porous rock that covers it. There are regions on Earth where some reaches the surface and the ancients spoke of pitch, bitumen, or asphalt. In ancient and medieval times, such petroleum seepages were more often looked on as medicines rather than fuels.
Of course, the surface seepages are in very minor quantities. Petroleum stores, however, are sometimes overlain with nonporous rock. The petroleum seeping upward reaches that rock and them remains below it in a slowly accumulating pool. If a hole can be drilled through the rock overhead, the petroleum can move up through the hole. Sometimes the pressure on the pool is so great that the petroleum gushes high into the air. The first successful drilling was carried through in 1859 in Titusville, Pennsylvania, by Edwin Drake.
If one found the right spot then it was easy to bring up the liquid material. It was much easier to do that than to send men underground to chip out chunks of solid coal. Once the petroleum was obtained, it could be moved overland through pipes, rather than in freight trains that had to be laboriously loaded and unloaded, as was the case with coal.
The convenience of obtaining and transporting petroleum encouraged its use. The petroleum could be distilled into separate fractions, each made up of molecules of a particular size. The smaller the molecules, the easier it was to evaporate the fraction.
Through the latter half of the nineteenth century, the most important fraction of petroleum was "kerosene", made up of middle-sized molecules that did not easily evaporate. Kerosene was used in lamps to give light.
Toward the end of the nineteenth century, however, engines were developed which were powered by the explosions of mixtures of air and inflammable vapors within their cylinders. The most convenient inflammable vapor was that derived from "gasoline", a petroleum fraction made up of small molecules and one that therefore vaporized easily.
Such "internal combustion engines" are more compact than earlier steam engines and can be made to start at a moments’ notice, whereas steam engines require a waiting period while the water reserve warms to be boiling point.
As automobiles, trucks, buses, and aircraft of all sorts came into use, each with internal combustion engines, the demand for petroleum zoomed upward. Houses began to be heated by burning fuel oil rather than coal. Ships began to use oil; electricity began to be formed from the energy of burning oil.
In 1900, the energy derived from burning petroleum was only 4 percent that of coal. After World War II , the energy derived from burning the various fractions of petroleum exceeded that of coal, and petroleum is not the chief fuel powering the world’s technology.
The greater convenience of petroleum as compared with coal is, however, balanced by the fact that petroleum exist on Earth in far smaller quantities than coal does. (This is not surprising, since the fatty substances from which petroleum was formed are far less common on Earth than the woody substances from which coal was formed.)
The total quantity of petroleum now thought to exist on Earth is about 14 trillion gallons. In weight that is only one-ninth as much as the total existing quantity of coal and, at the present moment, petroleum is being used up much more quickly. At the present rate of the use, the world’s supply of petroleum may last for only thirty years or so.
There is another complication in the fact that petroleum is not nearly so evenly distributed as coal is. The major consumers of energy have enough local coal to keep going but are, however, seriously short of petroleum. The United Stated has 10 percent of the total petroleum reserves of the world in its own territory, and has been a major producer for decades. It still is, but its enormous consumption of petroleum products is now making it an oil importer, so that it is increasingly dependent on foreign nations for this vital resource. The Soviet Union has about as much petroleum as the United States, but it uses less, so it can be an exporter.
Nearly three-fifths of all known petroleum reserves on Earth is to be found in the territory of the various Arabic-speaking countries. Kuwait, for instance, which is a small nation at the head of the Persian Gulf, with an area only three-fourths that of Massachusetts and a population of about half a million, possesses about one-fifth of all the known petroleum reserves in the world.
The political problems this creates are already becoming crucial.
In what way is petroleum unlike coal?
选项
答案
Petroleum is unlike coal. It may be the product of the accumulating fatty matter of ocean organisms instead of originating in accumulating woody matter. What’s more, petroleum is not nearly so evenly distributed as coal is.
解析
转载请注明原文地址:https://kaotiyun.com/show/mkua777K
本试题收录于:
翻译硕士(翻译硕士英语)题库专业硕士分类
0
翻译硕士(翻译硕士英语)
专业硕士
相关试题推荐
People’smediationcommitteeformediation
Therearemorerichpeoplethaneverbefore,includingsome7millionmillionaires,andover400billionaires.Fromsippingcham
________wasthefirstEnglishwriterwhowasawardedNobelPrizeforliterature.
A______isagrowthoffeathers,furorskinalongthetopoftheheadsofsomeanimals,especiallybirds.
EventhoughthefolktalesPerroultcollectedandretoldwerenotsolelyFrenchinorigin,hisversionsofthemweresodecidedly
Ateighto’clockshelaid______whatevershewasdoingtotellthechildrenastorybeforetheywenttobed.
Thosewhosupportviolenceontelevisionclaimthatithelpstheviewerto______steamandtogetridofhisfeelingsinaharm
ChildrenasyoungasfourwillstudyShakespeareinaprojectbeinglaunchedtodaybytheRoyalShakespeareCompany.TheRSC
Frenchtoys:onecouldnotfindabetterillustrationofthefactthattheadultFrenchmanseesthechildasanotherself.Allt
Becausethehighseriousnessoftheirnarrativesresultedinpartfromtheirmetaphysics,Southernwriterwerepraisedfortheir
随机试题
Windows帮助和支持分________和________两种方式,联机服务需要互联网的支持,可以通过联机获得更多的帮助信息。
阅读下列材料,并根据材料后的问题做出解释说明:英国的地方政府真正开始于盎格鲁.撒克逊时期的地方郡制。在9世纪初威撒克斯国王统一英格兰后,设立了比较正规的地方政府。15世纪末16世纪初都铎王朝统治英国后,英国地方政府的最大变化是设立治安法官,旨在平
张某,女,23岁。患尖锐湿疣,外生殖器及肛门出现疣状赘生物,色灰,质柔软,表面秽浊潮湿,触之易出血,恶臭,小便色黄,不畅,舌苔黄腻,脉弦数。治拟利湿化浊,清热解毒。应首选
不符合水痘特点的是()
根据《宪法》的规定,关于国家结构形式,下列哪一选项是正确的?()
(2004)除尘系统的风管不宜采用哪种敷设方式?
用做预应力筋的钢筋冷拉时,应采用的方法是( )。
科学家做过一个实验:拍打放有跳蚤的桌子,跳蚤迅即跳起,高度是其身长的一百倍以上。然后给跳蚤罩上一个玻璃罩,这一次跳蚤碰到了玻璃罩。连续多次后,跳蚤改变了起跳高度以适应环境,每次跳跃总保持在罩顶以下的高度。接下来逐渐降低玻璃罩的高度,跳蚤都在碰壁后主动改变自
软件计划是软件开发的早期和重要阶段,此阶段要求交互和配合的是
Nottoomanydecadesagoitseemed"obvious"bothtothegeneralpublicandtosociologiststhatmodemsocietyhaschangedpeopl
最新回复
(
0
)