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考研英语阅读理解有一部分是截取自报刊文章，因此考生在复习备考的过程中要注意提高报刊文章的阅读能力，把握时事阅读。下面新东方在线小编分享历年真题同源的30篇报刊文章，附有注释和解析，希望考生认真阅读，提高对此类文章的阅读能力和增加相关词汇量。
考研英语阅读真题同源报刊文章30篇（24）
Can coal be clean?
Coal has several advantages as a fuel. It is abundant. It is widely
distributed: countries that are short of other fossil fuels, such as Germany and
South Africa, have mountains of it. As a result, it is cheap. Even though the
price has risen in the past few years, it is still less expensive to run a power
plant on coal than on almost anything else.
But coal is also dirty. It releases lots of soot and various noxious
chemicals as it burns, and so has fallen out of favour in many Western
countries. Worse, coalfired plants produce roughly twice as much carbon dioxide
per unit of electricity generated than those that run on natural gas.
The obvious solution is to make coalfired generation cleaner. And that’s
what utilities in Western countries have been doing for years, to comply with
ever stiffer airpollution standards. Reducing emissions of carbon dioxide,
however, is another matter. In Britain, as in most rich countries, the average
efficiency of coalfired power stations is about 35%. But Mitsui Babcock, an
engineering firm, says its most recent designs can achieve efficiencies as high
as 46%. It reckons that switching from an old design to a new one can cut fuel
consumption and emissions by 23%.
Many methods can reduce the various emissions produced by coalfired power
stations, so that they are at least no worse than gasfired stations. But
technologies also exist to make coal cleaner still, by filtering out carbon
dioxide from the flue gas and storing it somehow. This is theoretically
possible, but expensive. Moreover, unlike modifications that improve efficiency,
there are no savings to be had by adding carboncapture technology to a power
plant. As a result, no such plants have been built.
How does carbon capture work? Most utilities are eyeing one of three basic
designs. The simplest, and easiest to bolt on to existing plants, treats carbon
dioxide like any other pollutant, and extracts it from the flue gas. Many firms
already use this "amine scrubbing" approach to remove carbon dioxide from
natural gas, for example. But it is not so practical for largescale uses, since
the amines are expensive, as is heating them to release the captured carbon
dioxide.
"Oxy fuel" plants sidestep the difficulties of separating oxygen and
nitrogen in the flue gas by burning coal in pure oxygen rather than air. The
resulting flue gas is almost pure carbon dioxide. But the energy used to
separate oxygen from air before burning is almost as great as that needed to
filter out nitrogen afterwards, leading to a similar loss of efficiency.
The third approach, called "integrated gasification combined cycle" (IGCC),
also requires oxygen, but for use in a chemical reaction rather than for
burning. When heated in oxygen, coal reacts to form carbon dioxide and hydrogen.
An amine solution then absorbs the carbon dioxide, while the hydrogen is burnt
in a modified furnace. The amine scrubbing is cheaper than usual, since the
reaction generates carbon dioxide in a more concentrated form. Engineers are
also experimenting with membranes that would allow hydrogen to pass, but not
carbon dioxide. There are four IGCC demonstration plants operating in America
and Europe, although none currently captures carbon dioxide permanently;
instead, it is simply released into the atmosphere. AEP’s planned new plants
will follow a similar design.
George Bush is a believer, at any rate. In 2003 he unveiled a subsidised
scheme to build a zeroemissions IGCC plant called "Future Gen" by 2013. The
European Union, for its part, is giving money to utilities dabbling in oxy fuel,
among other schemes. Handouts from the taxpayer are needed, power firms argue,
since the technology in question is still young. But it is hard to believe that
it will ever grow up unless subsidies give way to stronger measures, such as
longterm caps or taxes on carbondioxide emissions. The technology to eliminate
such emissions from coalfired plants exists, but it will not be adopted without
regulatory incentives from governments.
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发表于 2017-8-6 15:51:16
