化學(xué)工程與工藝專業(yè)英語unit(已修改)
2025-08-17 21:22 本頁面
【正文】 Unit 21 Chemical Industry and Environment化學(xué)工業(yè)與環(huán)境How can we reduce the amount of waste that is produced? And how we close the loop by redirecting spent materials and products into programs of recycling? All of these questions must be answered through careful research in the ing years as we strive to keep civilization in balance with nature. 我們怎樣才能減少產(chǎn)生廢物的數(shù)量？我們怎樣才能使廢棄物質(zhì)和商品納入循環(huán)使用的程序？所有這些問題必須要在未來的幾年里通過仔細(xì)的研究得到解決，這樣我們才能保持文明與自然的平衡。1. Atmospheric ChemistryCoalburning power plants, as well as some natural processes, deliver sulfur pounds to the stratosphere, where oxidation produces sulfuric acid particles that reflect away some of the ining visible solar radiation. In the troposphere, nitrogen oxides produced by the bustion of fossil fuels bine with many organic molecules under the influence of sunlight to produce urban smog. The volatile hydrocarbon isoprene, well known as a building block of synthetic rubber, is also produced naturally in forests. And the chlorofluorocarbons, better known as CFCs, are inert in automobile air conditioners and home refrigerators but e apart under ultraviolet bombardment in the midstratosphere with devastating effect on the earth’s stratospheric ozone layer. The globally averaged atmospheric concentration of stratospheric ozone itself is only 3 parts in 10 million, but it has played a crucial protective role in the development of all biological life through its absorption of potentially harmful shoutwavelength solar ultraviolet radiation.1．大氣化學(xué) 燃煤發(fā)電廠像一些自然過程一樣，也會釋放硫化合物到大氣層中，在那里氧化作用產(chǎn)生硫酸顆粒能反射入射進(jìn)來的可見太陽輻射。在對流層，化石燃料燃燒所產(chǎn)生的氮氧化物在陽光的影響下與許多有機物分子結(jié)合產(chǎn)生都市煙霧。揮發(fā)的碳?xì)浠衔锂愇於?，也就是眾所周知的合成橡膠的結(jié)構(gòu)單元，可以在森林中天然產(chǎn)生含氯氟烴。我們所熟悉的CFCs，在汽車空調(diào)和家用冰箱里是惰性的，但在中平流層內(nèi)在紫外線的照射下回發(fā)生分解從而對地球大氣臭氧層造成破壞，全球大氣層中臭氧的平均濃度只有3ppm，但它對所有生命體的生長發(fā)育都起了關(guān)鍵的保護(hù)作用，因為是它吸收了太陽光線中有害的短波紫外輻射。During the past 20 years, public attention has been focused on ways that mankind has caused changes in the atmosphere: acid rain, stratospheric zone depletion, greenhouse warming, and the increased oxidizing capacity of the atmosphere. We have known for generations that human activity has affected the nearby surroundings, but only gradually have we noticed such effects as acid rain on a regional then on an intercontinental scale. With the problem of ozone depletion and concerns about global warming, we have now truly entered an era of global change, but the underlying scientific facts have not yet been fully established.在過去的二十年中，公眾的注意力集中在人類對大氣層的改變：酸雨、平流層臭氧空洞、溫室現(xiàn)象，以及大氣的氧化能力增強，前幾代人已經(jīng)知道，人類的活動會對鄰近的環(huán)境造成影響，但意識到像酸雨這樣的效應(yīng)將由局部擴展到洲際范圍則是慢慢發(fā)現(xiàn)的。隨著臭氧空洞問題的出現(xiàn)，考慮到對全球的威脅，我們已真正進(jìn)入到全球話改變的時代，但是基本的科學(xué)論據(jù)還沒有完全建立。2. Life Cycle AnalysisEvery stage of a product’s life cycle has an environmental impact, starting with extraction of raw materials, continuing through processing, manufacturing, and transportation, and concluding with consumption and disposal or recovery. Technology and chemical science are challenged at every stage. Redesigning products and processes to minimize environmental impact requires a new philosophy of production and a different level of understanding of chemical transformations. Environmentally friendly products require novel materials that are reusable, recyclable, or biodegradable。 properties of the materials are determined by the chemical position and structure. To minimize waste and polluting byproducts, new kinds of chemical pr
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