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
【F1】Petroleum is the largest source of liquid fuel, and, in spite of attempts to develop synthetic fuels, and the continued use
【F1】Petroleum is the largest source of liquid fuel, and, in spite of attempts to develop synthetic fuels, and the continued use
admin
2017-10-23
89
问题
【F1】
Petroleum is the largest source of liquid fuel, and, in spite of attempts to develop synthetic fuels, and the continued use of solid fuels, world consumption of petroleum products is about four times greater now than in 1940.
Crude petroleum oil from different oilfields is never exactly identical in composition. Although all petroleum is composed essentially of a number of hydrocarbons, they are present in varying proportions in each deposit, and the properties of each deposit have to be evaluated.【F2】
Samples are subjected to a series of tests in the laboratory, the object of which is largely to determine the correct processing methods to be adopted in each case.
Petroleum is not normally used today in the crude state.【F3】
The mixture of oils of which it is composed must be separated out into a number of products such as petrol, aviation spirit, kerosene, diesel oils and lubricants, all of which have special purpose.
The main method of separation used, in refineries is fractional distillation, although further processing is normally required to produce marketable petroleum products. The different hydrocarbons present in petroleum have different boiling temperatures, and the fractions can therefore be isolated according to their boiling temperatures. Petrol, for instance, is a mixture of the lower-boiling hydrocarbons, with boiling temperatures ranging from 100℃ to 400℃. Diesel oils on the other hand have boiling temperatures of upwards of 400℃.
【F4】
Distillation was originally carried out in batch—stills and, although this is still done for special purposes, the development of the pipe—still has revolutionized refinery processes, since it allows continuous vaporization and rectification of the fractions.
The pipe-still consists of a bricok-lined furnace, in which is fitted a battery of tubes, through which the crude oil is pumped. The oil is heated, and petrol vaporization occurs. The oil then enters the fractionating tower, where it is distilled by coming into contact with condensed vapor which has previously been evolved from the still. Fractions of different boiling ranges are drawn off at different points in the tower, or, in some plants, in a series of towers, each one distilling successively heavier fractions.
【F5】
The heavier distillates, such as gas oil, undergo various other processes, of which the most important is known as cracking.
In this process, they are heated to a temperature of about 550℃, as a result of which the heavier molecules are broken up, lighter oils such as petrol being produced. Catalytic cracking, in which silicon compounds are used as catalysts to aid the process of decomposition, gives higher octane petrols. These are widely used as motorcar fuels, since the high octane value reduces the tendency of the fuel to detonation.
【F5】
选项
答案
重质馏出液例如粗柴油,还要经过其他一些加工处理,其中最重要的是所谓的裂化。
解析
句子中出现了两个表示列举的词汇,第一个是such as,而第二个先行词processes之后有which引导的非限定性定语从句。一方面可以理解这个定语从句限定先行词,另一方面通过关系代词之后的the most important判断词部分是对processes的一个列举。因此在处理句子时,应采用重译法,即译为“其最重要的是……”。distillate“精华,蒸馏物“;undergo“经历,遭受,忍受”;cracking“破裂,裂化”。
转载请注明原文地址:https://kaotiyun.com/show/40IZ777K
0
考研英语一
相关试题推荐
Lonelypeople,itseems,areatgreaterriskthanthegregariousofdevelopingillnessesassociatedwithchronicinflammation,s
Lonelypeople,itseems,areatgreaterriskthanthegregariousofdevelopingillnessesassociatedwithchronicinflammation,s
Comparisonsweredrawnbetweenthedevelopmentoftelevisioninthe20thcenturyandthediffusionofprintinginthe15thand1
Comparisonsweredrawnbetweenthedevelopmentoftelevisioninthe20thcenturyandthediffusionofprintinginthe15thand1
Comparisonsweredrawnbetweenthedevelopmentoftelevisioninthe20thcenturyandthediffusionofprintinginthe15thand1
Comparisonsweredrawnbetweenthedevelopmentoftelevisioninthe20thcenturyandthediffusionofprintinginthe15thand1
Comparisonsweredrawnbetweenthedevelopmentoftelevisioninthe20thcenturyandthediffusionofprintinginthe15thand1
Comparisonsweredrawnbetweenthedevelopmentoftelevisioninthe20thcenturyandthediffusionofprintinginthe15thand1
随机试题
溃疡性结肠炎与下列脏腑无关的是
下列关于借款费用暂停或停止资本化的相关表述中,正确的是()。
《物业管理条例》的法律责任的特点是()
一般情况下,初中生的思想品德的发展在科尔伯格的道德发展阶段论中位于()阶段。
《义务教育数学课程标准(2011年版)》中所说的“数学基本思想”主要指()、数学推理的思想和数学建模的思想.
树木的年轮不仅记录着树的年龄,而且指示着方向。年轮一般总是一面稀疏一面密集。那么,在中国北方平原上的树木,年轮密集的一面指向的是:
“深入浅出”这个成语中主要涉及的迁移类型是()
论述完善人权司法保障制度的措施。
数据库设计分为以下6个设计阶段:需求分析阶段、【】、逻辑设计阶段、物理设计阶段、实施阶段、运行和维护阶段。
Whatdoesthewomanmean?
最新回复
(
0
)