化工专业英语Lesson 6(共5页)

1、 Lesson 6 Ammonia氨 A1 Dinitrogen makes up more than three-quarters of the air we breathe , but it is not readily available for further chemical use.在我们呼吸的空气中，有超过(chogu)3/4是氮气，但是要进一步的化学应用并不简单。2 Biological transformation of nitrogen into useful chemicals is embarrassing for the chemical industry, sinc

2、e all the effort of all the industrys technologists has been unable to find an easy alternative to this. 对于化学工业来说，利用(lyng)生物转化法将氮气转化为有用的化学产品是很困难的，因为所有工厂的技术专家做了很多努力也没有找到一个容易的方法。3 Leguminous plants can take nitrogen from the air and convert it into ammonia and ammonium-containing products at atmospher

3、e pressure and ambient temperature; 豆科植物可以在大气压和常温下将空气中的氮转化为氨和含有(hn yu)铵基的物质。4 despite a hundred years of effort ,the chemical industry still needs high temperatures and pressures of hundreds of atmospheres to do the same job. 但是对于化学工业，尽管经过了一百多年的努力，要完成相同的工作，仍需要高温和高出大气压几百倍的高压。5 Indeed, until the inven

4、tion of the Haber process, all nitrogen-containing chemicals came from mineral sources ultimately derived from biological activity.实际上，在哈伯博斯制氨法发明之前，所有含氮的化学产品是从矿物中提取出来的，最终通过生物方法得到。 B1 Essentially all the nitrogen in manufactured chemicals comes from ammonia derived from the Haber-based process. 本质上而言

5、，所有已制备的化学产品中的氮都来自于哈伯博斯制氨法制备的氨。2 So much ammonia is made (more molecules than any other compound, though because it is a light molecule greater weights of other products are produced), and so energy-intensive is the process, that ammonia production alone was estimated to use 3% of the Worlds energy s

6、upply in the mid-1980s.制备大量的氨（由于氨分子较轻，因此尽管生产的其它产品的量更大，但氨的分子数要多于其他任何化合物），需要在过程中消耗大量的能源，在20世纪80年代中期，生产氨产品消耗的能源约占世界能源供给的3%。C The Haber Process For Ammonia Synthesis氨合成中的哈伯博斯制氨法1 Introduction. All methods for making ammonia are basically fine-tuned versions of the process developed by Haber, Nernst and

7、Bosch in Germany just before the First War.介绍。哈伯、能斯特和波希于一战前在德国开发出了哈伯工艺，现在所有的合成氨方法基本工艺都是以该法为基础、再稍微加以改变的。 N2+3H2=2NH3 D1 In principle the reaction between hydrogen and nitrogen is easy; it is exothermic and the equilibrium lies to the right at low temperatures. 从理论上来讲，氢气和氮气的反应很简单，反应是放热的，在低温时，平衡向右移动。2

8、Unfortunately, nature has bestowed dinitrogen with an inconveniently strong triple bond, enabling the molecule to thumb its nose at thermodynamics. 不幸的是，自然赠与了氮分子强烈的三键结合，使该分子不易受热力学因素的影响。3 In scientific terms the molecule is kinetically inert ,and rather severe reaction conditions are necessary to get

9、 reactions to proceed at a respectable rate.用科学术语来说，该分子是动力学惰性的，因此，要使该反应以一定的速度进行，需要相当苛刻的反应条件。4 A major source of “fixed” (meaning, paradoxically , “ usefully reactive”) nitrogen in nature is lightning, where the intense heat is sufficient to create nitrogen oxides from nitrogen and oxygen.自然界中“固定(gdn

10、g)”（与“有效(yuxio)的活动性”相反）氮的一个主要的来源是闪电(shndin)，巨大的热量使氮气和氧气生成氮的氧化物。 E1 To get a respectable yield of ammonia in a chemical plant we need to use a catalyst. 在化工厂里，为了得到氨的可观的产量，我们需要使用催化剂。2 What Haber discovered-and it won him a Noble prize-was that some iron compounds were acceptable catalysts. 哈伯发现一些铁的化合物

11、可以做催化剂，这使他获得了诺贝尔奖。3 Even with such catalysts extreme pressures (up to 600 atmospheres in early processes) and temperatures (perhaps 400 ) are necessary.但是，即使有这些催化剂，这个反应仍然需要很高的压力（在早期的工艺中高达600个大气压）和高温（大约400）。 F1 Pressure drives the equilibrium forward, as four molecules of gas are being transformed in

12、to two.由于四个气体分子转化为两个气体分子，所以增加压力使平衡向右移动。2 Higher temperatures, however, drive the equilibrium the wrong way, though they do make the reaction faster, chosen conditions must be a compromise that gives an acceptable conversion at a reasonable speed. 虽然高温可以加快反应速度，但它使平衡向反向移动，因此，所选的条件必须要适当，从而使反应在合理的速率下有令人

13、满意的转化率。3 The precise choice will depend on other economic factors and the details of the catalyst. 反应条件的准确选择将取决于其他的经济因素和催化剂的具体情况。4 Modern plants have tended to operate at lower pressures and higher temperatures (recycling unconverted material) than the nearer-ideal early plants, since the capital an

14、d energy casts have become more significant.现代工厂已倾向于在更低压和更高温下操作（回收没有转化的材料），因为投资费用和能量费用已变得更为重要。 G1 Biological fixation also uses a catalyst which contains molybdenum (or vanadium) and iron embedded in a very large protein, the detailed structure of which eluded chemists until late 1992. 氮的生物固定也要使用催化剂

15、，催化剂是将钼（或这钒）和铁嵌入巨大的蛋白质中，细微的结构困扰着化学家直到1992后期。2 How it works is still not understood in detail.它是如何起作用的直到现在也没有完全弄明白。 H1 Raw Materials. The process requires several inputs: energy, nitrogen and hydrogen. 原料。过程中需要的原料有：能量、氮气和氢气。2 Nitrogen is easy to extract from air, but hydrogen is another problem.氮气很容易

16、从空气中提取，但氢气是一个问题。3 Originally it was derived from coal via coke which can be used as a raw material (basically a source of carbon) in steam reforming, where steam is reacted with carbon to give hydrogen, carbon monoxide and carbon dioxide. 最初，氢气是从煤中得到的，将焦炭作为一种原材料（碳的一种基本的来源）在水蒸汽中转化，水蒸气和碳反应生成氢气、一氧化碳和二氧

17、化碳。4 Now natural gas (mainly methane) is used instead, though other hydrocarbons from oil can also be used.现在由天然气代替（主要成分是甲烷），也可以用石油中的其他碳氢化合物。5 Ammonia plants always include hydrogen-producing plants linked directly to the production of ammonia.合成氨工厂经常包含生产氢的工厂，它直接影响氨的生产。I1 Prior to reforming reaction

18、s, sulphur-containing compounds must be removed from the hydrocarbon feedstock as they poison both the reforming catalysts and the Haber catalysts. 在转化反应之前，碳氢化合物中含硫的物质必须先去除，原因(yunyn)是它们会污染转化的催化剂和哈伯催化剂。2 The first desulphurization stage involves a cobalt-molybdenum catalyst, which hydrogenates all su

19、lphur-containing compounds to hydrogen sulfide. 第一个脱硫阶段(jidun)涉及的是钴-钼催化剂，它使所有含硫的化合物与氢反应生成硫化氢。3 This can be removed by reaction with zinc oxide (to give zinc sulfide and water).硫化氢可以用氧化锌去除(q ch)（生成硫化锌和水）。J1 The major reforming reactions are typified by the following reactions of methane (which occur

20、over nickel-based catalysts at about 750):CH4+H2OCO+3H2 synthesis gas（混合气体）CH4+2H2OCO2+4H2下面是主要转化反应的一个典型的反应，甲烷的反应（反应中镍作催化剂，反应温度大约750）。2 Other hydrocarbons undergo similar reactions.其他的碳氢化合物发生的反应相似。K1 In the secondary reformers, air is injected into the gas stream at about 1100. 在二次转化炉中，在1100时，将空气注入到

21、气流中。2 In addition to the other reactions occurring, the oxygen in the air reacts with hydrogen to give water, leaving a mixture with close to the ideal 3:1 ratio of hydrogen to nitrogen with no contaminating oxygen. 除了其他反应发生之外，空气中的氧气和氢气反应生成水，剩余的混合气中，氢气和氮气接近理想比例3：1和没有被污染的氧气。3 Further reactions, howev

22、er, are necessary to convert more of the carbon monoxide into hydrogen and carbon dioxide via the shift reaction:CO+H2OCO2+H2然而，需要进一步的变换反应将一氧化碳转化为氢气和二氧化碳。K1 This reaction is carried out at lower temperatures and in two stages (400 with an iron catalyst and 220 with a copper catalyst) to ensure that

23、conversion is as complete as possible.此反应发生的温度较低（400时使用铁催化剂，220时使用铜催化剂），为了保证转化尽可能的完全，使用两段反应。M1 In the next stage, carbon dioxide must be removed from the gas mixture, and this is accomplished by reacting the acidic gas with an alkaline solution such as potassium hydroxide and/or mono-or di-ethanolam

24、ine.下一个阶段，需要在混合气中去除二氧化碳，完成这步骤是通过酸性气体和碱性溶液的反应，如氢氧化钾或乙醇胺或着是单一的乙醇胺。N1 By this stage there is still too much contamination of the hydrogen-nitrogen mixture by carbon monoxide (which poisons the Haber catalysts), and another step is needed to get the amount of CO down to ppm levels. 在这各阶段，氢-氮混合气中仍然有很多的一氧

25、化碳污染物（污染哈伯催化剂），需要另外的步骤使得CO的数量降到ppm（百万分之一）的数量级。2 This step is called methanation and involves the reaction of CO and hydrogen to give methane (i.e. the reverse of some of the reforming steps). 这个步骤被叫做甲烷化作用，涉及的反应为CO和氢气生成甲烷（即转化步骤的逆过程）。3 The reaction operates at about 325 and uses a nickel catalyst.反应发生

26、(fshng)的温度约为325，使用(shyng)镍做催化剂。4 Now the synthesis gas mixture is ready to go into a Haber reaction.现在(xinzi)，合成的气体混合物进入哈伯反应。 O1 Ammonia Production. The common features of all the different varieties of ammonia plant are that the synthesis gas mixture is heated, compressed and passed into a reactor

27、containing a catalyst. 合成氨产品。各种各样不同的合成氨的工厂的普遍特征是，合成的气体混合物受热、加压、通过一个装有催化剂的反应器。2 The essential equation for the reaction is simple:N2+3H2=2NH3反应基本的化学式很简单： P1 What industry needs to achieve in the process in an acceptable combination of reaction speed and reaction yield. 过程中，工业上需要达到的是：反应的速率和产量都是可接受的。2

28、Different compromises have been sought at different times and in different economic circumstances. 在不同的时期和不同的经济环境中寻找不同的折中的方案。3 Early plants plumped for very high pressure (to get the yield up in a one-pass reactor), but many of the most modern plants have accepted much lower one-pass yields at lower

29、 pressures and have also opted for lower temperatures to conserve energy. 早期的工厂选择非常高的压强（为了使收益率上升，选择单程反应器），但是很多现代的工厂接受更低的单程收益率，反应的压强更低，同时选择更低的反应温度来节约能源。4 In order to ensure the maximum yield in the reactor the synthesis gas is usually cooled as it reaches equilibrium.为了保证反应器中的产量最大，通常在反应平衡时冷却合成气。5 Thi

30、s can be done by the use of heat exchangers or by the injection of cool gas into the reactors at an appropriate point. 这可以通过使用热交换器或在适当的时候向反应器内注入冷却的气体来实现。6 The effect of this is to freeze the reaction as near to equilibrium as possible.这样做的效果是尽可能在平衡时凝结反应。7 Since the reaction is exothermic (and the eq

31、uilibrium is less favorable for ammonia synthesis at higher temperatures) the heat must be carefully controlled in this way to achieve good yields.由于反应时放热的（高温对于合成氨反应的平衡是没有利的），必须小心的控制热量来获得好的产量。 Q1 The output from the Haber stage will consist of a mixture of ammonia and synthesis gas so the next stage

32、 needs to be the separation of the two so that the synthesis gas can be recycled. 哈伯阶段的产物将包括合成气和氨气的混合气，所以下一阶段需要使这两种气体分离，合成气还可以循环利用。2 This is normally accomplished by condensing the ammonia (which is a good deal less volatile than the other components, ammonia boils at about -40).这通常通过压缩氨气来实现（与其他组分相比

33、，氨气是少见的易挥发的气体，氨气的沸点大约为-40）。 R1 Use of Ammonia. The major use of ammonia is not for the production of nitrogen-containing chemicals for further industry use, but for fertilizers such as urea or ammonium nitrates and phosphates. 氨气的应用。氨气的主要应用并不是生产含氮的化学产品，做进一步的工业应用，而是用来制备化肥，比如尿素、硝酸铵和磷酸盐。2 Fertilizers consume 80% of all the ammonia produced. 生产的氨，80%用在了化肥上。3 In the USA in 1991, for example, the following ammonia-derived products were consumed, mostly for fertilizers (amounts in millions of tonnes): urea (4.2); ammonium sulphate (2.2); ammonium nitrate (2.6); diammonium hydrogen phosphate (1