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
外语
The energy contained in rock within the earth’s crust represents a nearly unlimited energy source, but until recently commercial
The energy contained in rock within the earth’s crust represents a nearly unlimited energy source, but until recently commercial
admin
2014-02-22
52
问题
The energy contained in rock within the earth’s crust represents a nearly unlimited energy source, but until recently commercial retrieval has been limited to underground hot water and/or steam recovery systems. These systems have been developed in areas of recent volcanic activity, where high rates of heat flow cause visible eruption of water in the form of geysers and hot springs. In other areas, however, hot rock also exists near the surface but there is insufficient water present to produce eruptive phenomena. Thus a potential hot dry rock(HDR)reservoir exists whenever the amount of spontaneously produced geothermal fluid has been judged inadequate for existing commercial systems.
As a result of recent energy crisis, new concepts for creating HDR recovery systems — which involve drilling holes and connecting them to artificial reservoirs placed deep within the crust — are being developed. In all attempts to retrieve energy from HDRs, artificial stimulation will be required to create either sufficient permeability or bounded flow paths to facilitate the removal of heat by circulation of a fluid over the surface of the rock.
The HDR resource base is generally defined to include crustal rock that is hotter than 150°C, is at depths less than ten kilometers, and can be drilled with presently available equipment. Although wells deeper than ten kilometers are technically feasible, prevailing economic factors will obviously determine the commercial feasibility of wells at such depths. Rock temperatures as low as 100°C may be useful for space heating; however, for producing electricity, temperatures greater than 200 °C are desirable. The geothermal gradient, which specifically determines the depth of drilling required to reach a desired temperature, is a major factor in the recoverability of geothermal resources. Temperature gradient maps generated from oil and gas well temperature-depth records kept by the American Association of Petroleum Geologists suggest that tappable high-temperature gradients are distributed all across the United States.(There are many areas, however, for which no temperature gradient records exist.)
Indications are that the HDR resource base is very large.If an average geothermal temperature gradient of 22 °C per kilometer of depth is used, a staggering 13,000,000 quadrillion B.T.U. ’s of total energy are calculated to be contained in crustal rock to a ten-kilometer depth in the United States. If we conservatively estimate that only about 0.2 percent is recoverable, we find a total of all the coal remaining in the United States. The remaining problem is to balance the economics of deeper, hotter, more costly wells and shallower, cooler, less expensive wells against the value of the final product, electricity and/or heat.
The primary purpose of the passage is to______.
选项
A、alert readers to the existence of HDRs as an available energy source
B、document the challenges that have been surmounted in the effort to recover energy from HDRs
C、warn the users of coal and oil that HDRs are not an economically feasible alternative
D、encourage the use of new techniques for the recovery of energy from underground hot water and steam
答案
A
解析
本题为主旨题。通读全文可知,本文主要讲述了干热岩(HDR)作为一种可再生能源的前景。A选项“提醒读者HDR作为一种可利用能源的存在”准确概述了全文内容,因此A项正确。
转载请注明原文地址:https://kaotiyun.com/show/XXQO777K
0
考博英语
相关试题推荐
Vitaminsareagroupofsubstancesfoundinfood.Thebodyneedsthemforlifeandhealth.Sonaturally,manypeopleareconcern
Thousandsofyearsagomanusedhandyrocksforhissurgicaloperations.Laterheusedsharpboneorhorn,metalknivesand,mor
Handwritinganalysis(graphology)circumventsthelawbyfryingtodetermineanemployee’straits(e.g.stability)accordingto
Canyouimagine!Heofferedme$5000tobreakmycontract.That’s______.OfcourseIdidn’tagree.Iwouldtakelegalaction.
Developingapeaceful,understanding,andsupportiverelationshipbetweenparentsandchildrenisnotaneasytask.Failurescan
Faces,likefingerprints,areunique.Didyou【C1】______wonderhowitispossibleforusto【C2】______people?Evenaskilledwrite
“打桥牌”(bridge)的风格是与同伴紧密合作,与另外两家组成的联盟斗智斗勇,进行激烈竞争。“打麻将”(mahjong)则是孤军作战,看着上家,防着下家,自己和不了,也不让别人和。在工作中,这种做法显然是不好的,尤其是自己出不了成绩,也不让人家出成绩,更
Toomuch______canpossiblyleadtounhappiness,eventothoughtsofsuicideasfewpeoplehavethecouragetoanalyzethemselves
Playingviolentvideogamescanhaveimmediateandlastingeffectsonaperson’sthoughtsandbehavior,newresearchshows.Inf
三名警官冒着大火的高温和浓烟救出了孩子们。
随机试题
对闭经患者进行药物撤退试验的目的是评估其体内()
治疗急性有机磷农药中毒致肺水肿的主要药物是
小儿遗尿的病机主要是
患者,女性,39岁。既往体健,近1月来发现记忆力减退、反应迟钝、乏力、畏寒,住院检查:体温35℃,心率60次/分,黏液水肿,血TSH升高,血FT4降低,可能的诊断是
患者李某,18岁,入院初诊为“骨肉瘤”。X线检查出现“日光射线”,此现象出现的主要原因是
关于桥梁结构动力(自振)特性的相关描述,错误的选项是()。
按照起重机械起重标准,某台额定起重量为2.5t的小起重能力的梁式起重机属于的类别是()。
矿井井筒施工阶段,进度控制的要点是()。
一般来说,新兴产业在发展期收益和风险分别是_______和_______。()
若有如下程序段:#include<iostream>usingnamespacestd;intmain(){char*p="abcdefgh",*r;r=p;cout<<*r<<e
最新回复
(
0
)