焦煤炉中英文对照外文翻译文献.docx

焦煤炉中英文对照外文翻译文献.docx

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焦煤炉中英文对照外文翻译文献

中英文对照外文翻译文献

（文档含英文原文和中文翻译）

原文：

Energysavingandsomeenvironment

improvementsincoke-ovenplants

Abstract

Theenthalpyofinletcoalandfuelgasisdischargedfromacoke-ovenplantinthefollowingforms:

chemicalandthermalenthalpyofincandescentcoke,chemicalandthermalenthalpyofcoke-ovengas,thermalenthalpyofcombustionexhaustgas,andwasteheatfromthebodyofthecokeoven.Inrecentyearstherecoveryofseveralkindsofwasteenergyfromcokeovenshasbeenpromotedmainlyforenergysavingpurposes,butalsofortheimprovementofenvironmentalconditions.Amongthevariousdevicesyetrealized,thesubstitutionoftheconventionalwetquenchingmethodwithacokedrycoolingisthemosttechnicallyandeconomicallyconvenient.Theaimofthispaperismainlyareviewofthemaintypesofcokedrycoolingplantsandadetailedexaminationoftheinfiuenceofsomeparameters,particularlyoftemperatureandpressureoftheproducedsteam,andontheenergyefficiencyoftheseplants.

1.Introduction

1.1.Usableenergy

Theenergyofasystem-environmentcombinationisusuallydefinedastheamountofworkattainablewhenthesystemisbroughttoastateofunrestrictedequilibrium（thermal,mechanicalandchemical）bymeansofreversibleprocesses,involvingonlytheenvironmentatauniformlyconstanttemperatureandpressureandcomprisingsubstancesthatareinthermodynamicequilibrium.Notwithstandingthequitedifferentmeaning,chemicalenergiesdifferfromlowerheating

valuesslightly,asisdiscussedin[1,2].Thechemicalenergygenerallyfallsbetweenthehigherandlowerheatingvaluesbutisclosertothehigher.

Nomenclature

cp

constantpressureheatcapacity[kJ/（kgK）]

Ex

energy[kJ]

Exu

usableenergy[kJ]

ex

specificenergy[kJ/kg]

Gv

volumeflowrate[m3（nTp）/h]

Gv*

specificvolumeflowrate[m3（nTp）/tdrycoke]

i

specificenthalpy[kJ/kg]

p

pressure[bar]

s

specificentropy[kJ/（kgK]

T

temperature[︒C,K]

To

environmenttemperature[︒C,K]

v

specificvolume[m3/kg]

Ф

energyeffciency[dimensionless]

Nonetheless,thechemicalenergyisnotsuitableforquantifyingthetechnicalvalueofafuelfortworeasons:

（i）Priortoconsideringheattransfer,itisnecessarytoaccountfortheessentiallyirreversiblecombustionprocess,whichdecreasestheexergiesofvariousfuelsgreatlyindifferentways.（ii）Theworkcorrespondingtoreversibleexpansionofseveralcomponents（inparticularCO2）downtotheiratmosphericpartialpressurescannotbeobtainedfromthecombustiongas,asisimplicitintheenergyde®nition.Inaddition,thisworkdifferswithfueltype.Consequently,Bisio[3]definedusableenergyastheexergeticvaluefollowinganadiabaticcombustionwithagivenexcessairratio（e.g.,1.1）minustheenergylossresultingfromirreversiblemixingofcom-bustiongaswiththeatmosphereafterhavingreachedatmosphericpressureandtemperature.

Theratioofusableenergytolowerheatingvalueofagivenfuelistermedthemeritfactor.Thisfactorisalwayslessthanoneandincreasesasthetechnicalandeconomicvaluesofafuelrise.

Theparameter“usableexergy”,ashasbeende®nedandappliedin[3],issuitableintheexamin-ationofplants,thatutilizefuelmixing,whentheaimistoreduceboththetotalfuelconsumptionand,chiefly,themorevaluablecomponentone.

1.2.Coke-ovenenergyrecoveries

Thechemicalenergyofafuelgas,whichisusedforacokeoven,amountsto2500-3200MJ/tdrycoal.Thisenergy,degradedtothermalenergyofvariousoperativevalues,isdischargedfromtheplantinsuchforms:

1.Thermalenergyofincandescentcoke（43-48%）

2.Thermalenthalpyofcoke-ovengas（24-30%）

3.Thermalenergyofwastegas（10-18%）

4.Permeability,convectionandradiationheatfromtheexternalsurfaceofcokeoven,andvariouslosses（10-17%）

Theoilcrisisof1973createdastrongimpulsetowardsanewthinkingontheconsumptionandrationalutilizationofenergy,particularlyinthehighlyindustrializedcountrieswithlimitedindigenousenergyresources.Atthesametime,attentionthroughouttheworldwasalsoincreas-inglyfocusedonenvironmentproblems.

Thepossibleutilizationofthethermalenergyofincandescentcokeisdealtwithinmanypapers.Usually,incokingtechnologythecokeiscooledbybeingsprayedwithwaterunderspecialquenchingtowers.Inrecentyears,thevarioustypesofdrycoolingplantsallowtherecov-eryofnearly80%ofthethermalenergyofincandescentcoke.Thepossibilitiesofutilizingreco-veredenergyareasfollows:

1.Productionofsteamandelectricity.

2.Preheatingofcokingcoal.

3.Roomheating.

Thethermalenergyofcoke-ovengas,whichisthesecondlargestintheabovelisting,hassofarbeenrarelyutilized.Variousstudies,however,havebeencarriedoutforthepossibleutilizationofthiswasteenergyandatechniquehasrecentlybeencommercializedinJapan.

Thethermalenergyofcombustionexhaustgasisutilizedtopreheatboththecombustionairandfuelgasmixturethroughalarge-capacityregenerator.Consequentlythewastegastemperatureisreducedtoapproximately200︒C.Lately,thefurtherrecoveryofheatfromwastegashasbeenreportedinafewcasesusingaheatpipeinstalledinthe¯ue.

Thevariouskindsofheatwastedfromthecoke-ovenexternalsurfacehavebeendecreasedbythereinforcedsealingandbetterthermalinsulationofcokeovens.

Inthefollowingsections,themaintypesofcoke-ovenenergyrecoverieswillbeconsideredforacomparison.

1.3.Protectionoftheenvironment

Aswiththeproblemofenergysavingandrecovery,thelastyearshavebeencharacterizedbyincreasedpreventionofatmosphericandwaterpollutionbyindustrialemissionsanddomesticwastes.Worktocontrolatmosphericpollutionhasbeencarriedoutinalldevelopedcountries.AccordingtoZaichenkoetal.,asaresultofincludingmeasuresforenvironmentalprotection,theinvestmentandthecokingcostsareincreasedby15%.However,ifthecalculationsincludedallowanceforlossescausedbyadverseeffectsofatmosphericpollutiononworkershealth,instal-lationofengineeringfacilitiesformaintainingcleanaircanbecost-effective.Inanycase,itisobviousthatanenvironmentalfacilityisparticularlytemptingwhen,aswithcokedrycoolingplants,inadditiontoenvironmentadvantages,anenergyrecoverycanbeassociated,eveniftheinvestmentcostsarehigherandnotjusti®edonlybyenergysaving.

2.Cokedryquenching

2.1.Methodsforenergyrecoveryandsavingfromcokeatthecoke-ovenoutlet

Theideaofrecoveringthermalenergyfromincandescentcokebymeansofaninertgasdatesbacktotheearly1900s.The®rstindustrialplants,designedparticularlybytheSulzerBrothers（Winterthur,Switzerland）werecarriedoutinthe'20sand'30sbothintheUSAandinEurope（Germany,France,UK,Switzerland）[4,18].However,thegreaterinvestmentcostsofdryquench-ingplants,incomparisonwiththoseofthewetquenchingones,wereamortizedwithdif®cultyinaperiodinwhichenergywasverycheap.Consequently,dryquenchingplantsweregivenup.

Intheearly1960s,anewinterestarose:

intheUSSR,drycoolingplants,whichbasicallyfollowedtheSulzerdesign,werebuiltwiththeprimaryaimofpreventingthecokefromfreezinginwinter,ashappenswithwetquenchedcoke.Theplant,constructedinvariouscountriesaccord-ingtotheSovietGiprokoksprocess[6],isschematicallyshowninFig.1.Thered-hotcoke,atatemperatureofabout1100︒C,ispushedfromovens,A,intocontainersplacedoncars.Loadedcarsaremovedtothedrycoolingplant,wherecontainers,B,areliftedbybridgecrane,C,andunloadedthroughthechargingsystem,D,intopre-chamber,E.Then,

hotcokeistransferredintothecoolingchamber,F,insmallbatches.Afterleavingthecoolingchamberthroughthedischarg-ingsystem,G,cokeruns,atatemperatureofabout200︒C,ontoconveyorbelt,H.Cokeisrefriger-atedbyacirculatinggas,composedmainlybynitrogenandmovedbythemainblower,I.Thisgastransfersthermalenergyinboiler,N,whichproducessuperheatedsteam,O,atapressureupto100bar.Beforeenteringtheboiler,thegasisscrubbedinthecoarsede-duster,J,removingcoarseparticlesofcokedusttoprotecttheboilersurfacefromerosion.Afterleavingtheboiler,thegasstreamsthroughthe®nededuster,K,where®nedustisscrubbedout.

In1983adrycoolingplant,schematicallyshowninFig.2,beganoperationinGermany.Itsmaincharacteristicisthat1/3ofthethermalenergyistransferreddirectlyfromthecoketothevaporizingwaterandtheremaining2/3throughtheinertgas.Theadvantagesarealowerquantityofcirculatinggaswithacorrespondinglylowerconsumptionofelectricalenergybytheblowerandagreaterenergyrecovery.Refrigeratingwallsinthecoolingchamberrepresentthecriticalpointoftheplanti.

InGermany,acombinationofthecokedrycoolingandcoalpreheatingplanthasbeendeveloped[5,9,14±16].Thissystemrealizesprimaryenergysaving（e.g.gas）insteadofenergyrecoveryoflowerenergyvalue（steam）andthusitisthermodynamicallypreferred（see,e.g.,[29]）.Inaddition,thewell-knownadvantagesofthesingleprocesseswithrespecttocokequalityandincreasedoutputhavebeencon®rmed.Thecompletelyclosedsystempermitssignificantenvironmentalimprovementsinthecokingplantsector,avoidingtheimmissionsofdustintotheatmosphereinapracticallycompleteway.

Jung[13]consideredtheconvenienceofusingwatergas（H2+CO）astheheattransferfluid.Indeed,watergashasathermaldiffusivitythreetimesthatofnitrogen,andthusitallowsustoreduce