Research on Handling the Flue Gas with Condensation Process Pays an Important Role.docx

Research on Handling the Flue Gas with Condensation Process Pays an Important Role.docx

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ResearchonHandlingtheFlueGaswithCondensationProcessPaysanImportantRole

TheworkofZhaoShuaibing

ZhaoShuaibing

ProfessorTianLe

Masterpostgraduate2013

15June2014

ResearchonHandlingtheFlueGaswithCondensationProcessPaysanImportantRole

inSavingTheEnergyFortheGas-firedBoiler

（BeijingUniversityofCivilEngineeringandArchitecture,Beijing100044）

Abstract:

Thecombinationofexistinggasboilerstatus,mainlyintheformofstructure,style,analyzesthemainresearchdirectionsofsavingtechnologyongasboilersystem..Inthepaper,Introducetheboilercontrolsystem,gasboilereconomizer,andhowtotakeadvantageoffluegaswasteheat.FromthecurrentsituationofChina'senergyandenvironmentalprotection,fueldistributionandresourceutilization,itdescribesthedevelopmentprospectsofthegasboilermarketinChina.

Keywords:

boilercontrolsystemgasboilereconomizerfluegaswasteheatenvironmentalprotection

Ⅰ.Introduction

Chinaisa"richcoal,lessgas,lackofoil"country,anditdeterminestheenergyofcoal-basedenergyconsumptionpatterns（LUandMA）.Withthedevelopmentoftheoilandgasindustry,theamountofgasboilerareconstantlyincreasing.However,countrysuffersthedoublepressureofenergyshortageandenvironmentalpollutionwiththerapiddevelopmentofeconomyandsociety.Especially,industrialboilers,whicharehighenergyconsumption,highemissionproducts,facewiththeenormouspressureofenergysaving,andtherelevantdepartmentsarealsoawareofthese.

Comparedwithcoal-firedboilers,thegasboilerhasagreatenergysavingandemissionreductioninthermalefficiency,pollutantemissions.However,theaspectsofenergyconservationstillhasgreatpotentialtobetapped.ThispapercombinesthestatusofChina'sgasboiler,analyzesthegasboilertechnologyfromtheenergypointofview,andprospectthedevelopmentandapplicationprospectsongasboiler.

II.IntroducetheGasboiler

A.Theprincipleofgassteamboiler

Gassteamboileristousegasfuels,suchasnaturalgas,liquefiedgas,citygasasfuel,burningoutquantityofheatintheoven,heatingthepotofwater,andmakeitboilintosteamheatenergyconversionequipment.Inthepan,whichisreleasedbycontinualgasfuelcombustioninfurnaceheatingenergy,itgeneratesteamunderpressurewiththetemperatureincreasing.Whentheboilingpointofwaterpressurerises,thepanissealed,andtheexpansionofthewatervaporislimitedinside,andthermodynamicpressureisformedatthesametime,whichisstrictlythatboilerwatervaporiswaterinthedrumconstantpressureheatingtosaturatedwatervaporizationformedagain.Ithasbeenwidelyusedasanenergysource（YE,KOU,Guang,andWANG）.

Boilerismainlycomposedofpotshellandfurnacebodyandensurethesafeandeconomiccontinuousoperationoftheattachment,instrumentaccessories,automaticcontrolandprotectionsystem,etc.Boilerdrumboilerdrumaroundthepartitionarrangementisakindofboilerwater-cooledwall,whichisarrangedbytworeturnpipefireworkssmokeboxturnbackbeforeinfrontofthedrum.Underthedrumandtheboxbetween,droppipeandwatercoolingwall,itisconstitutedbytheframeworkofthecombustionchamber.inordertoreducesteamoutofthewater,theupperdrumhasthesteamseparator.Thebottomofthepotbodyheatingsurfaceisdrum,water-cooledwallpipeandfireworks（BALandZHANG）.

Amajorpartoftheboilerare:

①Thechamberofastoveorfurnace:

theboilerfuelburningandconvectionheatingsurfacecanmaketheoutletfluegastemperaturecooledtosafetyworkvalues.

②Economizer,usingtheboilertailfluegasheattoheatwater,toreduceexhausttemperature,andhavetheeffectoffueleconomy.

③Drum:

tolinktogetherandalltheheatingsurfaceandwaterwall,watercirculationloopadroptube,etc.Drumstoresoda,canadapttotheloadchange,withinternalsodaseparationdevicetoensurethequality,theonce-throughboilerdrum.

④Waterwall:

boilermainradiationheatingsurface,theabsorptionchamberofastoveorfurnaceradiantheat,heatingmedium,protectfurnacewall,etc.

⑤Combustionequipment,fuelandcombustionairintothefurnaceandthefuelneededforstableburning,burninggood.

⑥Airpreheater,heatingfuelwiththeair,tostrengthentheignitionandcombustion;absorptionfluegaswasteheat,reduceexhausttemperature,improvetheefficiencyoftheboiler.

⑦Brickworkistoprotecttheboilershell,sealingandheatpreservationeffect.Heavywallofsmallboilercanalsoplaysaroleofsupportingtheboilerparts.

⑧Framework,supportingandfixingboilercomponents.

Boilerancillaryequipmentmainlyinclude:

①Leadthewindequipment:

byinduceddraftfanandpipewillbeproducedintheoperationoftheboilerfluegastotheatmosphere.

②Dustremovalequipment:

despitetheflyashofboilerfluegas.

③Fuelsupplyequipment,storageandtransportationfuel.

④Watersupplyequipment:

thefeedwaterpumpwillbeafterdealingwiththewatertreatmentequipmentofwaterintotheboiler.

⑤Dustremovingslagequipment:

toremoveashfromtheboilerandaway.

⑥Airsupplyequipment:

throughblowersaftertheairpreheatertoheattheairtothechamberandgrindingcoaldeviceapplications.

⑦Automaticcontrolequipment:

automatictesting,processcontrol,automaticprotectionandautomaticadjustment.

B.Gasboilertypeselection

Drybackboilerandallwetbackboiler.Dryturn-backbackofboilerfluegasisfromrefractorytoroundintothespace;Allwetbackboilerfluegasturn-backspaceiscomposedofsoakinthewaterbackintothecombustionchamber（LIandZHAO,137）.Drybackboilerstructureissimple,buttherefractoriesiseasytodamage,andatthebackofthefurnaceandtubeplateafteroftendirectlyerodedbythehightemperaturefluegas,whichleadstothelargetemperaturedifference.However,althoughallwetbackboilerstructureismuchmorecomplicated,itisabletoavoidtheturn-backfluegassealingproblemofthespace,andmoresuitableformicropositivepressurecombustion.Sothecurrentselectionshouldconsiderthreereturnbackallwettypeboiler.

C.IntroducetheBoilercontrol

Basicmainboilerautomaticcontrolsystem:

Theboilerautomaticcontrolsystem,programcontroller,burner,temperaturesensor,pressuresensor,waterlevelsensor,etc.Automaticcontrolsystem:

PLCtechnology,invertertechnology,timecontroltechnology,fuzzycontroltechnologyinonebody.Inthesystem,accordingtothecontrolcharacteristicsofboilerandtheanalysissystemrequirements,itcanfinishthefunctionsofloadmanual,automaticadjustment,fillingwaterpumpautomaticallyadjustment.AccordingtothecontrolrequirementanalysissystemforPLCsystemconfiguration,aswellasthecontrolofI/OpointsandtheI/Oportallocation,itcanimplementthreeimpulsecontrol,thecombustionprocessofboilerwaterlevelautomaticcontrol,steampressureautomaticcontrol,etc.

Forexample:

Combustionmachinewindandgasratiocontrol.Thedesignofthegeneralgasboilerefficiencycanreach90%,butinactualoperation,duetothechangingexternalenvironmenttemperature,heatingloadchangesatanytime.Ifthecombustionmachinewindandgasratiocontrolisnottobeadjusted,theamountofgaswilloftencauseinadequateorexcessiveheatingquantity,andcauseenergywaste.

Gasflowcontrolprinciple:

whentheheatneedtochange,throughchangingintotheamountofgascombustionsystemtochangeintotheenergyofthewholesystemsoastorealizemakefulluseofenergyandsavetheresources.

III.Gasboilereconomizer

A.Bootstrapanalysis

（1）Fluegaswasteheat

Thecondensingtypegasboilercantakeadvantageoftheboilerexhaustheatboilerfeedwater,andmakeitsfromroomtemperature（about20℃）increasedto50-60℃andthenintothedrum,thefluegastemperaturefrom100degreestobelow70degrees.Becauseofmostofthewatervaporcondensation,recyclingtheboilerexhaustofsensibleheatandlatentheatcanbeabletoreducethegasconsumption,andboilerthermalefficiencycanreach10%orso.

（2）Thecondensedwaterrecycling

Thecondensedwaterhasalotofheat,usuallyabout20~30%oftotalquantityofheatofsteam,andsomeequipmentcanbeashighas40%.Soifhightemperaturecondensedwatercanbeusedasboilermake-upwatercycle,itwillnotonlysavethewater,butalsowillsavealotoffuel.Atthesametime,itcanreducetheboilerfluegasemissions,andprotecttheenvironment.

B.Boilerthermalefficiency

Beforedeterminingthethermalefficiencyofgas-firedboilerbyusingtheanti-balancemethod,youmustfirstdeterminewhattheheatlosscomefrom:

（1）Dryproductsofcombustionheatloss;

（2）theheatlosscausedbymoistureintheair;（3）heatlossduetomoistureinthefuel;（4）theheatlossofwaterfromthecombustionofhydrogeninthefuelcaused;（5）aheatlosscausedbecauseoftheunburnedcombustibles;（6）surroundingtheradiationloss.

Above

（1）to（4）,itistheheatlossiscommonlyreferredtoq2;（5）heatlossbyincompletechemicalcombustionq3andincompletemechanicalheatlossq4;（6）thecorrespondingheatlossq5;（7）theashphysicalheatlossq6.

Comparedwiththecoal-firedboilers,theheatlossofgasboilersinq4q6iszero.Gasboilerthermalefficiencyformula（LI,MAWeiandZHANG,65）following:

;

Where:

theboilerthermalefficiency;q2:

heatlosses;q3:

incompletechemicalcombustionloss;q5:

heatloss;Ipy:

exhaustenthalpy,;αpy:

smokeattheexcessairratio;IOlk:

eachstandardcubicmetersofgastosendhometheheat,;Qr:

eachstandardcubicmetersofgasintothefurnaceheat;q2:

gasb