化学工程与工艺专业英语unit1

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：32Unit1ChemicalIndustryBeforereadingthetextbelow,trytoanswerfollowingquestions:1.Whendidthemodernchemicalindustrystart?2.Canyougiveadefinitionforthechemicalindustry?3.Whatarethecontributionswhichthechemicalindustryhasmadetomeetandsatisfyourneeds?4.Isthechemicalindustrycapital-orlabor-intensive?Why?1.OriginsoftheChemicalIndustryAlthoughtheuseofchemicalsdatesbacktotheancientcivilizations,theevolutionofwhatweknowasthemodernchemicalindustrystartedmuchmorerecently.ItmaybeconsideredtohavebegunduringtheIndustrialRevolution,about1800,anddevelopedtoprovidechemicalsforusebyotherindustries.Examplesarealkaliforsoapmaking,bleachingpowderforcotton,andsilicaandsodiumcarbonateforglassmaking.Itwillbenotedthattheseareallinorganicchemicals.Theorganicchemicalsindustrystartedinthe1860swiththeexploitationofWilliamHenryPerkin’sdiscoveryofthefirstsyntheticdyestuff—mauve.AtthestartofthetwentiethcenturytheemphasisonresearchontheappliedofchemistryinGermanyhadpaidoffhandsomely,andby1914hadresultedintheGermanchemicalindustryhaving75%oftheworldmarketinchemicals.ThiswasbasedonthediscoveryofnewdyestuffsplusthedevelopmentofboththecontactprocessforsulphuricacidandtheHaberprocessforammonia.Thelatterrequiredamajortechnologicalbreakthroughthatofbeingabletocarryoutchemicalreactionsunderconditionsofveryhighpressureforthefirsttime.TheexperiencegainedwiththiswastostandGermanyingoodstead,particularlywiththerapidlyincreaseddemandfornitrogen-basedcompounds(ammoniumsaltsforfertilizersandnitricacidforexplosivesmanufacture)withtheoutbreakofWorldWarIin1914.Thisinitiatedprofoundchangeswhichcontinuedduringtheinter-waryears(1918-1939).Since1940thechemicalindustryhasgrownataremarkablerate,althoughthishasslowedsignificantlyinrecentyears.Thelion’sshareofthisgrowthhasbeenintheorganicchemicalssectorduetothedevelopmentandgrowthofthepetrochemicalsareasince1950.Theexplosivegrowthinpetrochemicalsinthe1960sand1970swaslargelyduetotheenormousincreaseindemandforsyntheticpolymerssuchaspolyethylene,polypropylene,nylon,polyestersandepoxyresins.Thechemicalindustrytodayisaverydiversesectorofmanufacturingindustry,withinwhichitplaysacentralrole.Itmakesthousandsofdifferentchemicalswhichthegeneralpubliconlyusuallyencounterasendorconsumerproducts.Thesesproductsarepurchasedbecausetheyhavetherequiredpropertieswhichmakethemsuitableforsomeparticularapplication,e.g.anon-sickcoatingforpansoraweedkiller.Thuschemicalsareultimatelysoldfortheeffectsthattheyproduce.2.DefinitionoftheChemicalIndustryAttheturnofthecenturytherewouldhavebeenlittledifficultyindefiningwhatconstitutedthechemicalindustrysinceonlyaverylimitedrangeofproductswasmanufacturedandthesewereclearlychemicals,e.g.,alkali,sulphuricacid.Atpresent,however,manythousandsofchemicalsareproduced,fromrawmaterialslikecrudeoilthrough(insomecases)manyintermediatestoproductswhichmaybeuseddirectlyasconsumergoods,orreadilyconvertedintothem.Thedifficultlycomesindecidingatwhichpointinthissequencetheparticularoperationceasestobepartofthechemicalindustry’ssphereofactivities,Toconsideraspecificexampletoillustratethisdilemma,emulsionpaintsmaycontainpoly(vinylchloride)/poly(vinylacetate).Clearly,synthesisofvinylchloride(oracetate)anditspolymerizationarechemicalactivities.However,ifformulationandmixingofthepaint,includingthepolymer,iscarriedoutbyabranchofthemultinationalchemicalcompanywhichmanufacturedtheingredients,isthisstillpartofthechemicalindustryordoesitnowbelonginthedecoratingindustry?Itisthereforeapparentthat,becauseofitsdiversityofoperationsandcloselinksinmanyareaswithotherindustries,thereisnosimpledefinitionofthechemicalindustry.Insteadeachofficialbodywhichcollectsandpublishesstatisticsonmanufacturingindustrywillhaveitsdefinitionastowhichoperationsareclassifiedas“thechemicalindustry”.Itisimportanttobearthisinmindwhencomparingstatisticalinformationwhichisderivedfromseveralsources.3.TheNeedforChemicalIndustryThechemicalindustryisconcernedwithconvertingrawmaterials,suchascrudeoil,firstlyintochemicalintermediates,andthenintoatremendousvarietyofotherchemicals.Thesearethenusedtoproduceconsumerproducts,whichmakeourlivesmorecomfortableor,insomecasessuchaspharmaceuticalproducts,helptomaintainourwell-beingorevenlifeitself.Ateachstageoftheseoperationsvalueisaddedtotheproductandprovidedthisaddedvalueexceedstherawmaterialplusprocessingcoststhenaprofitwillbemadeontheoperation.Itistheaimofchemicalindustrytoachievethis.Itmayseemstrangeintextbooklikethisonetoposethequestion“doweachemicalindustry?”However,tryingtoanswerthisquestionwillprovide(i)anindicationftherangeofthechemicalindustry’sactivities,(ii)itsinfluenceonourlivesineverydayterms,and(iii)howgreatissociety’sneedforachemicalindustry.Ourapproachinansweringthequestionwillbetoconsidertheindustry’scontributiontomeetingandsatisfyingourmajorneeds.Whatarethese?Clearlyfood(anddrink)andhealthareparamount.Otherwhichweshallconsiderintheirturnareclothingand(briefly)shelter,leisureandtransport.(1)Food.Thechemicalindustrymakesamajorcontributiontofoodproductioninatleastthreeway