化学工程与工艺专业英语 UNIT 1.ppt

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1、 化学工程与工艺专业英语化学工程与工艺专业英语授课班级：化工05授课教师：郎中敏学 时：32Unit 1 Chemical IndustryBefore reading the text below,try to answer following questions:l1.When did the modern chemical industry start?l2.Can you give a definition for the chemical industry?l3.What are the contributions which the chemical industry has ma

2、de to meet and satisfy our needs?l4.Is the chemical industry capital-or labor-intensive?Why?1.Origins of the Chemical Industry Although the use of chemicals dates back to the ancient civilizations,the evolution of what we know as the modern chemical industry started much more recently.It may be cons

3、idered to have begun during the Industrial Revolution,about 1800,and developed to provide chemicals for use by other industries.Examples are alkali for soapmaking,bleaching powder for cotton,and silica and sodium carbonate for glassmaking.It will be noted that these are all inorganic chemicals.The o

4、rganic chemicals industry started in the 1860s with the exploitation of William Henry Perkins discovery of the first synthetic dyestuffmauve.At the start of the twentieth century the emphasis on research on the applied of chemistry in Germany had paid off handsomely,and by 1914 had resulted in the G

5、erman chemical industry having75%of the world market in chemicals.This was based on the discovery of new dyestuffs plus the development of both the contact process for sulphuric acid and the Haber process for ammonia.The latter required a major technological breakthrough that of being able to carry

6、out chemical reactions under conditions of very high pressure for the first time.The experience gained with this was to stand Germany in good stead,particularly with the rapidly increased demand for nitrogen-based compounds(ammonium salts for fertilizers and nitric acid for explosives manufacture)wi

7、th the outbreak of World War I in 1914.This initiated profound changes which continued during the inter-war years(1918-1939).Since 1940 the chemical industry has grown at a remarkable rate,although this has slowed significantly in recent years.The lions share of this growth has been in the organic c

8、hemicalssector due to the development and growth of the petrochemicals area since 1950.The explosivegrowth in petrochemicals in the 1960s and 1970s was largely due to the enormous increase in demand for synthetic polymers such as polyethylene,polypropylene,nylon,polyesters and epoxy resins.The chemi

9、cal industry today is a very diverse sector of manufacturing industry,within which it plays a central role.It makes thousands of different chemicals which the general public only usually encounter as end or consumer products.Theses products are purchased because they have the required properties whi

10、ch make them suitable for some particular application,e.g.a non-sick coating for pans or a weedkiller.Thus chemicals are ultimately sold for the effects that they produce.l 2.Definition of the Chemical Industry At the turn of the century there would have been little difficulty in defining what const

11、ituted the chemical industry since only a very limited range of products was manufactured and these were clearly chemicals,e.g.,alkali,sulphuric acid.At present,however,many thousands of chemicals are produced,from raw materials like crude oil through(in some cases)many intermediates to products whi

12、ch may be used directly as consumer goods,or readily converted into them.The difficultly comes in deciding at which point in this sequence the particular operation ceases to be part of the chemical industrys sphere of activities,To consider a specific example to illustrate this dilemma,emulsion pain

13、ts may contain poly(vinyl chloride)/poly(vinyl acetate).Clearly,synthesis of vinyl chloride(or acetate)and its polymerization are chemical activities.However,if formulation and mixing of the paint,including the polymer,is carried out by a branch of the multinational chemical company which manufactur

14、ed the ingredients,is this still part of the chemical industry or does it now belong in the decorating industry?It is therefore apparent that,because of its diversity of operations and close links in many areas with other industries,there is no simple definition of the chemical industry.Instead each

15、 official body which collects and publishes statistics on manufacturing industry will have its definition as to which operations are classified as“the chemical industry”.It is important to bear this in mind when comparing statistical information which is derived from several sources.l 3.The Need for

16、 Chemical Industry The chemical industry is concerned with converting raw materials,such as crude oil,firstly into chemical intermediates,and then into a tremendous variety of other chemicals.These are then used to produce consumer products,which make our lives more comfortable or,in some cases such

17、 as pharmaceutical products,help to maintain our well-being or even life itself.At each stage of these operations value is added to the product and provided this added value exceeds the raw material plus processing costs then a profit will be made on the operation.It is the aim of chemical industry

18、to achieve this.It may seem strange in textbook like this one to pose the question“do we a chemical industry?”However,trying to answer this question will provide(i)an indication f the range of the chemical industrys activities,(ii)its influence on our lives in everyday terms,and(iii)how great is soc

19、ietys need for a chemical industry.Our approach in answering the question will be to consider the industrys contribution to meeting and satisfying our major needs.What are these?Clearly food(and drink)and health are paramount.Other which we shall consider in their turn are clothing and(briefly)shelt

20、er,leisure and transport.(1)Food.The chemical industry makes a major contribution to food production in at least three ways.Firstly,by making available large quantities of artificial fertilizers which are used to replace the elements(mainly nitrogen,phosphorus and potassium)which are removed as nutr

21、ients by the growing crops during modern intensive farming.Secondly,by manufacturing crop protection chemical,i.e.,pesticides,which markedly reduce the proportion of the crops consumed by pests.Thirdly,by producing veterinary products which protect livestock from disease or cure their infections.(2)

22、Health.We are all aware of the major contribution which the pharmaceutical sector of the industry has made to help keep us all healthy,e.g.by curing bacterial infections with antibiotics,and even extending life itself,e.g.-blockers to lower blood pressure.(3)Clothing.The improvement in properties of

23、 modern synthetic fibers over the traditional clothing materials(e.g.cotton and wool)has been quite remarkable.Thus shirts,dresses and suits made from polyesters like Terylene and polyamides like Nylon are crease-resistant,machine-washable,and drip-dry or non-iron.They are also cheaper than natural

24、materials.Parallel developments in the discovery of modern synthetic dyes and the technology to“bond”them to the fiber has resulted in a tremendous increase in the variety of colors available to the fashion designer.Indeed they now span almost every color and hue of the visible spectrum.Indeed if a

25、suitable shade is not available,structural modification of an existing dye to achieve this can readily be carried out,provided there is a satisfactory market for the product.Other major advances in this sphere have been in color-fastness,i.e.,resistance to the dyebeing washed out when the garment is

26、 cleaned.(4)Shelter,leisure and transport.In terms of shelter the contribution of modern syntheticpolymers has been substantial.Plastics are tending to replace traditional building materials like wood because they are lighter,maintenance-free(I.e.they are resistant to weathering and do notneed paint

27、ing).Other polymers,e.g.urea-formaldehyde and polyurethanes,are important insulating materials for reducing heat losses and hence reducing energy usage.Plastics and polymers have made a considerable impact on leisure activities with applications ranging from all-weather artificial surfaces for athle

28、tic tracks,football pitches and tennis courts to nylon strings for racquets and items like golf balls and footballs made entirely from synthetic materials.Likewise the chemical industrys contribution to transport over the years has led to major improvements.Thus development of improved additives lik

29、e anti-oxidants and viscosity index improvers for engine oil has enabled routine servicing intervals to increase from 3000 to 6000 to12000 miles.Research and development work has also resulted in improved lubricating oils and greases,and better brake fluids.Yet again the contribution of polymers and

30、 plastics has been very striking with the proportion of the total automobile derived from these materialsdashboard,steering wheel,seat padding and covering etc.now exceeding 40%.So it is quite apparent even from a brief look at the chemical industrys contribution to meeting our major needs that life

31、 in the world would be very different without the products of the industry.Indeed the level of a countrys development may be judged by the production level and sophistication of its chemical industry.4.Research and Development(R&D)in Chemical Industries One of the main reasons for the rapid growth o

32、f the chemical industry in the developed world has been its great commitment to,and investment in research and development(R&D).A typical figure is 5%of sales income,i.e.the total money received,which has to pay for raw materials,overheads,staff salaries,etc.,as well.In the past this tremendous inve

33、stment has paid off well,leading to many useful and valuable products being introduced to the market.Example include synthetic polymers like nylons and polyesters,and drugs and pesticides.Although the number of new products introduced to the market has declined significantly in recent years,and in t

34、imes of recession the research department is usually one of the first to suffer cutbacks,the commitment to R&D remains at very high level.The chemical industry is a very high technology industry which takes full advantage of the latest advances in electronics and engineering.Computers are very widel

35、y used for all sorts of applications,from automatic control of chemical plants,to molecular modeling of structures of new compounds,to the control of analytical instruments in the laboratory.Individual manufacturing plants have capacities ranging from just a few tonnes per year in the fine chemicals

36、 area to the real giants in the fertilizer and petrochemical sectors which range up to 500,000 tonnes.The latter requires enormous capital investment,since a single plant of this size can now cost$250 million!This,coupled with the widespread use of automatic control equipment,helps to explain why th

37、e chemical industry is capital-rather than labor-intensive.The major chemical companies are truly multinational and operate their sales and marketing activities in most of the countries of the world,and they also have manufacturing units in a number of countries.This international outlook for operations,or globalization,is a growing trend within the chemical industry,with companies expanding their activities either by erecting manufacturing units in other countries or by taking over companies which are already operating there.