Wet-To-Dry ConversionBottom Ash & Fly Ash Systems

Wet-To-DryThe Evolution to Dry Ash Handling

What is “Dry”?

InDuSTry TrEnDS

•IncreasInggovernmentregulatIons

•ashpondcapacItyconstraInts

•WateravaIlabIlIty

•groWIngdemandForreuseoFash

publicscrutiny,environmentalconcernsandpendinggovernmentregulationsmayfurthershifttheindustrytodryorreducedwaterconsumptionalternatives.Increasedfocusonconvertingwetbottomashsystemsisexpectedtoeliminatelegacyashponds.state-of-the-artashhandlingsystemsfromuccoffergreaterequipmentreliabilityandthebroadestrangeofcustomizedsolutionstobetterserveremovaloperations.

“dry”isoftenusedintheindustrytorepresentplacementintoalandfill,notnecessarilythemethodofconveying.theobjectiveformostutilitiesistoeliminatethepond–notalwaystheuseofwaterfromtheashconveyingprocessforflyandbottomash.however,someplantswillneedtominimizeoreliminatewaterfromtheconveyingprocessduetolimitedwatersupplyorenvironmentalconcerns.theseconditionsframetheavailablechoices,whichrangefromcontinueduseofwaterto100%eliminationofwater.

Ash Handling Solutions

recenthigh-profileincidentssurroundingashpondfailuresareforcingcoalpowerplantstore-evaluatewetashhandlingpractices.utilitycompaniesstillusingashretentionpondstostoreashby-producthaveimportantchoicesastheylooktoreplacewetsystemswithdrysolutions.overthepastfewdecadesunitedconveyorcorporation(ucc)hasassistedmanyutilitiesinconvertingfromwetflyashtodrysystemsbasedonthesemarkettrendsandfactors:

• Inconjunctionwiththepowderriverbasinfuel-switchinginitiatives• aslocalmarketsemerged,enablingthereuseandsaleofflyashtoconcretesuppliers• toextendthepondlifeforbottomashstorageofcapacity-constrainedponds.

asof2008,nearly67%ofplantswithashpondshaveconvertedtodryflyashsystems,whileonly10%ofbottomashsystemsaredry.

Wet-To-DryExperience Mattersunitedconveyorcorporationisdedicatedtothedevelopmentoftechnology,systemsandproductsthataddresstheneedsofcoal-firedpowerplants.asarecognizedindustryleader,wepartnerwithutilities,designengineeringfirmsandpowergenerationcompaniesworldwidetohelpdeliversolu-tionsthatmakeapositiveimpactonplantperformance.

since1920,ucchassetthestandardforinnovation,performanceandcustomerservice.Wehavethebroadestofferinginflyandbottomashsystemstodelivertherightsolutionandoptimalperformanceforyourplant.

One Company...the Right Solution

Fly Ash Systems

• vacuumsystems(nuveyor®)• pressuresystems(nuvaFeeder®,depac®andmultidactm)• combinationvacuum/pressuresystems• highdensityslurrysystem

Bottom Ash Systems

• recirculationsystems• submergedFlightconveyors(sFctm)• pneumaticashextractors(paXtm)• vibratingashextractors(vaXtm)

uCC ASH HAnDlIng SOluTIOnS ArE...

•specIFIcallyengIneeredForeachplant

•desIgnedtoImproveplantperFormance

•envIronmentallyFrIendlysolutIons

Fly Ash SystemsFly Ash Choices

dryflyashconveyinghasbecomethestandardfornewinstallationsandretrofitsoverthelastfewdecades.since1920,ucchasengineeredthousandsofflyashinstallationsinover50countries.retrofittinganexistingwethydroveyor®systemintoadryflyashsystemiscompletedwiththeadditionofafewsystemcomponents.

usingourtechnicalexperience,breadthofsystemsandproducts,uccworksdirectlywithcustomerstofindtherightsolutiontoaddresscurrentandfutureenvironmentalregulationrequirements.theoptionsincludethenuveyor®vacuumsystem,combinationvacuum/pressuresystem(nuvaFeeder®formediumphaseordepac®fordensephasematerials)orpressuresystem.

thereareseveralfactorstoanalyzewhendecidingwhichofthedryflyashsolutionswouldbethebestchoicefortheplant.

Conversion utilizes Existing Hydroveyor® Vacuum System

Common Criteria used to Evaluate Fly Ash Choices:

• currentandFutureFuel–areanyfuelchangesplanned?• existingpipe–Whatisthesizeandrouting?• headroom–howmuchheadroomisavailableunderthehoppers?• vacuum/pressuretransferstation–Ifrequired,whereisitlocated?• location–Wherewillthefinalstoragesilobelocated?• distance/routing–howfartothefinaldisposalpoint/silo?• capacity–Whatistheashgenerationrateandhowmanydaysofstorageisrequired?• Finaldisposalmethod–Willtheashbedisposedofconditionedordry?• aftermarketconsiderations–Whataretheashmarketing/resaleconsiderations?

nuMBEr OF InSTAllATIOnS

2000+nuVEyOr –

1000+nuVA FEEDEr –

400+DEPAC –

50+MultiDAC –

Phase Dilute Medium Dense Dense

Maximum Distance 1500 feet 8000 feet 5200 feet 1500 feet (450 meters) (2400 meters) (1600 meters) (450 meters)

Maximum Capacity 80 TPH 175 TPH 200 TPH 130 TPH (75 mTPH) (155 mTPH) (180 mTPH) (120 mTPH)

Material Ratio 5-22 5-22 25-60 25-60 Ash : Air Ash : Air Ash : Air Ash : Air

Air Velocity 3000-5200 ft/min 2400-4800 ft/min 900-2700 ft/min 900-2700 ft/min (16-27 m/sec) (12-25 m/sec) (5-15 m/sec) (5-15 m/sec)

Maximum Conveyor 20 inches Hg 40 psi 60 psi 60 psi Line Pressure (530 mm Hg) (275 kPa) (415 kPa) (415 kPa)

Fly Ash Systems nuVEyOr® nuVA FEEDEr® DEPAC® MultiDACTM

(Vacuum) (Pressure) (Pressure) (Pressure)

Fly Ash SystemsVacuum Systemthenuveyorvacuumflyashsystemistheindustrystandardforefficient,reliableashremovaluptoadistanceof1500ft.(450m)andinstalledcapacitiesupto80tph.Whenconvertingfromwet-to-dryflyashconveying,theexistingvacuumequipmentistypicallyreusedtoreducecosts.

theadditionofafewsystemmodificationsisallthatisrequired:

• Filter/separator• storagebinsandunloadingequipment•mechanicalexhausterorvacuumpumps• newyardandsiloconnectionpiping

nuVEyOr SySTEM•reuseeXIstIngvacuumsystem•easeoFretroFItInlImItedspace

combinationvacuum/pressuresystemsareusedwhentheconveyingdistanceexceedsthecapabilitiesofavacuumsystem.thesystemcontinuestotakeadvantageofthesimplicityandlowercostofexistingvacuumintakesbeneaththeashcollectors,whileprovidingthebenefitsofapressuresystem–highcapacityandlongdistanceconveyingtoremotedrystoragebins.Inavacuum/pressuresystem,anexhaustercreatestheairstreamtoconveyflyashfromtheprecipitatororothercollectionhopperstoatransfertank.Fromthatpoint,anuvaFeederoradepacsystemisusedtomovetheashtoastoragesilo.

nuVA FEEDEr SySTEM•abIlItytoconveylongdIstances•canhandleeconomIZerash

DEPAC SySTEM•densephase-loWvelocIty

Combination Vacuum/Pressure Systems

vacuumsystemwithsilo

Pressure SystemsWithsufficientheadroomunderthecollectionhoppers,theexistingvacuumsystemcanbereplacedwithanuvaFeeder,depacormultidacsystem,eliminatingtheneedforintermediatetransfertanks.

Filter/separatortopressuresystem

Bottom Ash SystemsChoosing The right Dry Bottom Ash System

Bottom Ash Choices

unitedconveyoroffersthebroadestrangeofstate-of-the-artdrybottomashhandlingsolutions.Fourdifferentsystemtypes–hydraulic,mechanical,pneumaticandvibratory–havebeendevelopedtoaddresstheparticularcharacteristicsofeachindividualpowerplant.Withhundredsofinstallationsandnearly90yearsofexperience,uccprovidestheconfidenceandpeaceofmindourcustomersdemand.

eachplantmustevaluatetheimportanceofdifferentcriteriawhenselectingtherightbottomashsystem.

Common Criteria used to Evaluate Bottom Ash Choices:

• physicalspaceconstraints–Whatsystemchoicesareavailable?• design,materialandInstallationcosts–Whatisthebudget?•maintenancecosts–Whatisthe20-yearlife-cyclecost?• timeavailableforInstallation–howlongistheoutage?•Waterusage/availability–howmuchwaterisavailableforashconveyinganddisposal?• operatingcosts–Whatarethepowerconsumptionrequirements?•multipleunitsynergies–canstoragetanksandsilosbeusedformultipleunits?• storage/disposal–howwillthebottomashbestored/used?

tableinformationbasedontypicalinstallation.

Total Installed Cost $$$$ $ $$ $$$

Lead Time 9 months 9 months 12 months 12 months

Outage

Pre-Outage Construction 6 months 2 months 3 months 3 months

Requirement Outage Construction 5 days 3 – 4 weeks 8 weeks 6 weeks

Outage Start-Up 2 – 3 days 1 – 2 days 3 – 4 days 1 – 2 days

Water

Make-Up Water 600 gpm 50 gpm None None

Consumption

Cooling Water 200 gpm 400 gpm None None

Conveying Water 400 gpm None None None (recirculating)

Power

Pumps 600 HP 50 HP None None

Consumption Blowers/Fans None None 200 HP 50 HP

Mechanical Drives 50 HP 100 HP 50 HP 75 HP

Boiler and Yard

Yard Piping Corridor Yes No Yes No

Space Boiler House Exit Corridor No Yes No Yes

Yard Footprint 6500 sq. ft. 1000 sq. ft. 1500 sq. ft. 1500 sq. ft.

Pumps Yes No No No

Operations and

Blowers/Fans No No Yes Yes

Maintenance Refractory Yes – existing Usually none Yes Usually none

Costs Conveyor Chain Replacement No Yes No No

Crushers Yes – existing Usually none Yes (2 – 3) Yes (1)

Conveying Pipeline/Valves Yes No Yes No

Bottom Ash Systems recirculation SFC PAX VAX (Hydraulic) (Mechanical) (Pneumatic) (Vibratory)

therewillbecertainplantlimitationsthatwillquicklyreducethechoicestooneortwooptions.Forexample,iftheashpondneedstobeeliminatedinthenext12-24monthsandthereisnochanceofaseveral-weekunitoutagetoreplaceequipment,theonlychoicebecomesahydraulicrecirculationsystem.If100%eliminationofwaterisrequired,thenthereareonlytwooptions:pneumaticconveying(paX)andvibratoryconveying(vaX).

Bottom Ash SystemsBOTTOM ASH SySTEMS

•recIrculatIonsystem

•submergedFlIghtconveyor(sFctm)

•pneumatIcasheXtractor(paXtm)

•vIbratoryasheXtractor(vaXtm)

nuMBEr OF InSTAllATIOnS

75+100+200+1,000+

rECIrCulATIOn SySTEM –

SuBMErgED FlIgHT COnVEyOr –

PnEuMATIC ASH EXTrACTOr –

HEAVy-DuTy HOT InDuSTrIAl APPlICATIOnS uTIlIzIng VIBrATOry TECHnOlOgy –

Bottom Ash SystemsSimple Conversion with a Successful Track recordarecirculationsystemconvertsawetsluicesystemintoa“dry”ashsystemwithoutchangetotheexistingbottomashhoppers.thissystemreusestheconveyingwaterandonlyrequiresasmallamountofmake-upwater.acompleterecirculationsystemreplacestheashpondwithdewateringbins,aclarifying(settling)tankandsurge(storage)tank.

thisisthesystemofchoicewhenwatersuppliesareavailableandminimaloutagetimeisrequiredtomaketheconversion.oncethesystemcomponentshavebeeninstalled,therecirculationsystemonlyrequiresafewdaysofoutagetimetoreroutethepipes.

recirculation System

•shortestoutagetImeForconversIon

•contInueduseoFeXIstIngbottomashhoppers

•easIlyIncorporatesmIllrejects

•elImInatesashstorageponds

System OperationInatypicalsystem,twodewateringbinsarerequired;onebinfillswhiletheotherisdewateredandunloadedintotrucksorrailcars.Wateroverflowstothesettlingtankandthenontothesurgetank.Inthesettlingtank,alargepercentageofthefineashcarryoversettlestothebottomandisreturnedtothedewateringbin.

Waterleavingthesettlingtankisdirectedtothesurge tankwhererecirculationpumpsreturnthewatertothe existingbottomashsluicesystem.

Bottom Ash Systems

System Operation

•contInuousremovaloFash

•loWpoWerconsumptIon

•easIlyIncorporatesmIllrejects

•elImInatesashstorageponds

Submerged Flight Conveyor (SFCtm)The Industry leader with Proven PerformancethesubmergedFlightconveyor(sFc)isaprovenbottomashsystemandthemostcost-effectivechoicewhencompatiblewiththeplantequipmentlayout.Whenreducingwaterconsumptionisamajordecidingfactor,thetypicalsFcsystemprovidesthelowestcostoption.Withinstallationsoperatingaroundtheworld,thissystemhasdemonstratedprovenperformanceandreliability.

theconveyorismanufacturedinvariousstandardwidths,makingiteasilyadaptabletomanyboilersizes.thesFcsystemiscompatiblewithpulverizedcoal-fired(pc)boilers,wetbottom(slagging)boilers,stoker-fedortravelinggateboilersandincinerators.

operationofthesubmergedFlightconveyorisverysimple.ashfallsfromtheboilerintoawater-filled,uppertroughthatquenchesandcoolstheash.chainsandflightsmovetheashalongthehorizontaltroughandupadewateringramp.

atthetopoftheramp,theashfallsthroughadischargechuteintoaconcretebunker,whereitcanbeloadedintotrucksforfinaldisposal.theflightscontinuethroughthelower(dry)chambertotherearoftheconveyorandthenreturntotheuppertrough.

Bottom Ash SystemsTime Proven Technology with routing Flexibilitythepneumaticashextractor(paX)systemisthepreferredretrofitsystemtoovercomestructuralbarrierswhencompleteeliminationofwaterisrequired.thepaXsystemutilizestime-provendryashstorageandvacuumconveyingtocollectandtransferbottomashinadrystate.thissystemalsoprovidesheatrecoveryandimprovedboilerefficiency.threesubsystemscompriseatypicalpaXsystem:

• adryhopperwheretheashiscollected,crushedandfedtothevacuumsystem.• avacuumsystemfordryashremovalandconveying.• astoragebinandunloadingequipmentforfinaldisposal.

System Operationsteepwallsandbottomdischargepermitgravityflowofashdownthehopper.griddoorsatthebottomofthehopperopentoallowashandclinkerstopassintothecrusher;whenclosed,thedoorspermitairtoflowintothehopperduringnon-conveyingcycles.thiscoolstheashandburnsresidualcarbon.Fromthecrusher,theashflowsintoavacuumconveyingsystemandontothestoragelocation.

Pneumatic Ash Extractor (PAXtm)

•easIlyretroFIttedaroundstructuralbarrIers

•provIdesImprovedheatrecoveryandboIlereFFIcIency

•doesnotrequIreWater

•elImInatesashstorageponds

[100% DRY]

Bottom Ash Systemsnext generation Technology for Dry Bottom Ash Handling

System Operationdesignedforsimplicityandsafetywithnointernalmovingparts,thevaXsystemrequiresvirtuallynomaintenanceanditsoveralloperationisunmatchedintheindustry.usingprovenvibratoryconveyingtechnology,ashisadvancedthroughaseriesofsuccessivethrowsusinganoscillatorytoss-and-catchmotion.controlledforceddraftairentersthroughthevibratoryconveyordeckandsurroundstheentireashsurfaceasitissuspendedbetweenthrows,creatingafluidizedbedofash.theresultisincreasedcoolingandcombustion.

Vibratory Ash Extractor (VAXtm)

•proventechnology

•hIghestheatrecovery

•loWeroperatIngcost

•elImInatesashstorageponds

thevibratoryashextractor(vaX)systemisthelatestevolutionofdrybottomashtechnology,transportingandcoolingashinoneefficientprocess.Itisthemostreliable,heavy-dutyandcost-effectivedrybottomashhandlingsystemonthemarket.

thevaXsystemfeaturesaruggeddesignanddurableconstructiontohandletheextremeoperatingconditionsofcoal-firedpowerplants.unlikeothermechanicalbottomashconveyorsystems,therearenomovingbeltsorhingedjointsthatcanbecomedamagedfromlargeslagfallsorforeignmaterialsuchassootblowerortubeshields.theresultissystemreliabilityandreducedriskofunplannedoutage.

[100% DRY]

m09-001©2009unitedconveyorcorporationuccisaregisteredtrademarkofunitedconveyorcorporation.

uccisyoursourceforallofyourashandreagenthandlingrequirements.

uCC Material Handling Solutions

Fly Ash (dilute,mediumanddensephase)

•vacuumsystems

•pressuresystems

Bottom Ash (Wetanddrysolutions)

•hydraulicsystems

•pneumaticsystems

•mechanicalsystems

•vibratorysystems

Mill rejects

•hydraulicsystem

•pneumaticsystems

reagent Handling Systems

Pulverized Fuel

System Components

•crushers

•tanks/vessels

• Filter /separators

• gates /valves

•mixer/unloaders

•pipe/Fittings

asanindustryinnovator,wehavelongbeenattheforefrontofashhandlingtechnology.Werecognizetheimportanceofprovidingcustomerswiththebestequipmentandlatesttechnologythatmeettheirdemandingrequirementsandplantneeds.

Withourownadvancedtestingandtechnologylab,weareabletomaintaincontroloverthequalityanddeliveryofoursystemsandequipment.theresultissuperiorandpredictableperformanceforourcustomers.

ourdedicatedteamofengineers,sales,serviceandin-housedesignteamspanstheglobecoveringsixcontinents,assuringyouthatwecanprovideexceptionalservicewheneverneeded.thisisourcommitmenttoyou.

The UCC Commitment

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