WPC5 ޝ^Ma/V) "0?_}^|j[1U%4 JqU..X=jcX9ݝ_\I>] mK1Q`{y-39״WYv_G- Q1;f*RYlMES(B(7:h Je6jphol!Z5&*&t5QT)z|k+d"-#2*RT T-?`h&Bn$z3V0˲ 3F>χr5Kܦ#^sɕh@ A)IQ$Ć졝ic 6IU{)&MVx202_);{N?W7j~Rkl~jz;#KYI][8 uCP6E@mgD_#!2 %SS 0RYY^ w@4  m 3 ; ; ; f f a N @ 0n[ D+ 0nabU :vvvvvvvMU, 0nU>NU*E B-[@ @oJJJJJJJJJJJJJJJJJJJJJJJJJJ AE2 0n2 D3P3 B3 0n3 0K4 AQY44 0Dp5Acrobat Distiller0"(*L$   X. {D|U}U~[[[EEU2};.8 3|xU Level 1Level 2Level 3Level 4Level 5ǘTABLE B 6 3'   X  _ " q!"  pV;<,(`~0!! `EX!!!!eXp  (# (#(#(# @  @ #" !" qX#"D["  @  @  @  @  @  @#  @ ,h"D[ @  @-  @ #"D[,h#-D["D[EPA452/F03_Ԅ028#"D[-D[&#,h"D[_ X w  ?+ 4 <DL!?#"D[,h# #" "D[I#"D["  t *D["D[#* *D[q#* q!*  t _AirPollutionControlTechnology I   FactSheet#* !* q##" * #" q!" ___ }  #" !" q#(F33$ L!   X  'dxd(F33$ L!   X  TABLE A,) AZ"Arial Regular,2AZArial <:Default ParaXXXXXX\  `&Times New Roman%2A`Arial)Hairline d Q  3)   X  _AY0) xdoEWxA X EPA_CICA_ԀFactSheet'(#DryElectrostaticPrecipitator(ESP) g <(#WirePlateType< WPC____ o0T#4\;c-C~%L0R,S-]:^;iHjItVuWdersÏď˝˝ҫӬں-Q.T0V2[4_6f8i:m@zDFG-O%,M)0P.5^:6g0BdDTxQrtvw9XF>\KC_QǿZql->.?1A/]jlfDjJDjJiYNDjg/ ]jlfi`VgNjjVRjlJTYd-/`jjGGjVVjgdj]RjjTi)/.5ljGT`djd]jdiVljlVi-/./././(6YJVd]VgjVVjigRjjlV6'./+/)/'+/)$= fDd]NJjjVTjdJjjDg=$'-/,%%,/.)$+/.)$$)-/'$%" djVTjNjDjJJjG`Djf "&$%)++*'$'*+(%$%(+)%$(+'$ / djVVjgVjdJjJJjJdljJT/  6$=  / jTVjdVjdJjGJjJfljg / @%$ / jJiVjVVJjdTjjRfdV`/ 5$9 /lj`VjjVi]VTN` / @&$ /NjJJNVYiVjjVYjD/ 7$%? //fddfVjj VfRJTJjVVDj //5$6/ #/iJjV`jJVjjVTjJj / / $5 / /  Tjl`VjGDjgVjjVdljdJj//1$:/#/  DlfVji]jYVjjTiVjRdlj"// #/1$:/#/ jJYldjVVjJjJiGjjTJjJ//2$A// jGVjYVjJj Jdjl]fNjJf /#/30$09/ #/ Gj]iljdJjGJj JdigYVV`//;$0A/ #/ `jjGTTDjGJjJTjiRjGi"//#/C<0$0Ah/ ##//YjGgDjJVjNjjGVTDjR/! / <0$2" ' '{'m?" ' 3Y"{'m@" $ $3 Openhearthfurnace VYEv(hAY X@99.2X@V99.2 YpCv(hB" X@99.2 X@Y X@99.2X@99.2 YpCv(hC" X@99.2 X@Y X@99.2X@99.2YOMv(hD" X@99.2 $ X@Y Y_________ Applicable_ԀSource_Type :_ _Point_______________ * F   _{ {| >.0$J |~ ~TypicalIndustrialApplications:~ ~{ {} X }Approximately_Ԁ80%ofall_ESPs_ԀintheU.S.areusedintheelectricutilityindustry._ESPs_Ԁarealsousedinpulpandpaper(7%),cementandotherminerals(3%),andnonferrousmetalsindustries(1%)(EPA,1998).Commonapplicationsofdrywireplate_ESPs_ԀarepresentedinTable2.&  "    @ Table2.TypicalIndustrialApplicationsofDryWirePlate_ESPs_Ԁ(EPA,1998)  G V*!d  dN Kd N Kd Kd Kd (#(#,<dd ,dd ,dd +  %YY  $%Application +YY  YY +SourceCategoryCode(SCC) +YY  YY +AreOtherESPTypes    AlsoTypicallyUsedforthisApplication? 2( ^ $ YY $2UtilityBoilers(Coal,Oil)   Y  101002...004   Y  No ," Y " $ $,IndustrialBoilers(Coal,Oil,Wood,LiquidWaste)   T  102001...005102009,013  ~ &  No ," T " $ $,Commercial/InstitutionalBoilers(Coal,Oil,Wood)  y!  103001...005103009  K  No ,"y! " $ $,ChemicalManufacture  F  Sitespecific  F  Yes ,"F " $ $,NonFerrousMetalsProcessing(PrimaryandSecondary):     A  ,"A " $ $,  Copper !0 303005304002  # Yes ,"$" $ $,  Lead %0 303010304004  U' Yes ,"(" $ $,  Zinc P)0 303030304008  z"+ Yes ,"P," $ $,  Aluminum u-0 303000...002304001  G/ Yes ,"u0" $ $,  Othermetalsproduction B10 303011...014304005...006304010...022  4 Yes 5+B5" $ $5FerrousMetalsProcessing: 63   7  5+8" $ $5_Ferroalloy_ԀProduction 93 303006...007  : No 5+;" $ $5IronandSteelProduction <3 303008...009  = Yes 5+>" $ $5GrayIronFoundries @6z?3 @1188@@304003 @6+z@ @1188 @ @No 5+zA" $ $5SteelFoundries  uB3 304007,009   uC Yes ," uD" $ $,PetroleumRefineriesandRelatedIndustries  !pE 306001...999  !pF No ,"!pG" $ $,MineralProducts:  "k H   "k I  5+"k J" $ $5CementManufacturing #f!K3 305006...007  #f!L No 5+#f!M" $ $5StoneQuarryingandProcessing @6$a"N3 L@1235L@@305020 @6+$a"O L@1235 L@ @Yes 5+$a"P" $ $5Other %\#Q3 305003...999  %\#R Yes ,"%\#S" $ $,Wood,Pulp,andPaper 7- &W$T @1277@7307001 @6+&W$U @1277 @ @Yes 3Y"&W$V" $ $3Incineration(MunicipalWaste) MY<'R%WY @1827@M501001 VYE:'R%X @1827 @Y VYes7-+'R%Y" $  Y 7' "GJ _Emission_ԀStreamCharacteristics:  (*'[     a.0  AirFlow: 󀀀Typicalgasflowratesforwireplate_ESPs_Ԁare100to500standardcubicmetersper +w)] second(sm3/sec)(200,000to1,000,000standardcubicfeetperminute(_scfm_)).Mostsmallerplate ,N*^ type_ESPs_Ԁ(50sm3/secto100sm3/sec,or100,000to200,000_scfm_)useflatplatesinsteadofwires x- +_ forthehighvoltageelectrodes(_AWMA_,1992).J.+`(#(# Ї  b.0  Temperature: 󀀀Wireplate_ESPs_Ԁcanoperateatveryhightemperatures,upto700C(1300F) X (_AWMA_,1992).OperatinggastemperatureandchemicalcompositionofthedustarekeyfactorsinfluencingdustresistivityandmustbecarefullyconsideredinthedesignofanESP. (#(#   c.0  PollutantLoading: 󀀀TypicalinletconcentrationstoawireplateESPare2to110g/_m3_(1to50 M grainspercubicfoot(gr/ft3)).Itiscommonto_pretreat_Ԁawastestream,usuallywithamechanical |$ collectororcyclone,tobringthepollutantloadingintothisrange.Highlytoxicflowswithconcentrationsbelow1g/_m3_(0.5gr/ft3)arealsosometimescontrolledwith_ESPs_Ԁ(_Bradburn_,1999;   Boyer,1999;Brown,1999). (#(#   d.0  OtherConsiderations: 󀀀Ingeneral,dry_ESPs_Ԁoperatemostefficientlywithdust_resistivities_  >  between5x103and2x1010ohmcm.Ingeneral,themostdifficultparticlestocollectarethose m   withaerodynamicdiametersbetween0.1and1.0_m_.Particlesbetween0.2and0.4_m_Ԁusuallyshowthemostpenetration.Thisismostlikelyaresultofthetransitionregionbetweenfieldanddiffusioncharging(EPA,1998). (#(#  EmissionStreamPretreatmentRequirements:  /  Whenmuchofthepollutantloadingconsistsofrelativelylargeparticles,mechanicalcollectorssuchascyclonesorspraycoolersmaybeusedtoreducetheloadontheESP,especiallyathighinletconcentrations.GasconditioningequipmenttoimproveESPperformancebychangingdustresistivityisoccasionallyusedaspartoftheoriginaldesign,butmorefrequentlyitisusedtoupgradeexisting_ESPs_.TheequipmentinjectsanagentintothegasstreamaheadoftheESP.Usually,theagentmixeswiththeparticlesandalterstheirresistivitytopromotehighermigrationvelocity,andthushighercollectionefficiency.ConditioningagentsthatareusedincludeSO3,H2SO4,sodiumcompounds,ammonia,andwater;theconditioningagentmostused  isSO3(_AWMA_,1992).   & y CostInformation:  8 Thefollowing'y :Ԁarecostranges(expressedin2002dollars)forwireplate_ESPs_Ԁofconventionaldesignundertypicaloperatingconditions,developedusingEPAcostestimatingspreadsheets(EPA,1996).Costscanbesubstantiallyhigherthanintherangesshownforpollutantswhichrequireanunusuallyhighlevelofcontrol,orwhichrequiretheESPtobeconstructedofspecialmaterialssuchasstainlesssteelortitanium.Ingeneral,smallerunitscontrollingalowconcentrationwastestreamwillnotbeascosteffectiveasalargeunitcleaningahighpollutantloadflow.,  a.0  CapitalCost: $21,000to$70,000persm3/sec($10to$33per_scfm_)$(#(#   b.0  O&MCost: $6,400to$74,000persm3/sec($3to$35per_scfm_),annuallyx! &(#(#   c.0  AnnualizedCost: $9,100to$81,000persm3/sec($4to$38per_scfm_),annually" ((#(#   d.0  CostEffectiveness: $38to$260permetricton($35to$236pershort_ton)~$&"*(#(# ~$&"*(#(# _< & y TheoryofOperation:  &h$-   AnESPisaparticulatecontroldevice'y&?Ԁthatuseselectricalforcestomoveparticlesentrainedwithinanexhauststreamontocollectorplates.Theentrainedparticlesaregivenanelectricalchargewhentheypassthroughacorona,aregionwheregaseousionsflow.Electrodesinthecenteroftheflowlanearemaintainedathighvoltageandgeneratetheelectricalfieldthatforcestheparticlestothecollectorwalls.Indry_ESPs_,thecollectorsareknocked,or"rapped",byvariousmechanicalmeanstodislodgetheparticulate,whichslidesdownwardintoahopperwheretheyarecollected.Thehopperisevacuatedperiodically,asitbecomesfull.Dustisremovedthroughavalveintoadusthandlingsystem,suchasapneumaticconveyor,andisthendisposedofinanappropriatemanner. %.+6 ЇInthewireplateESP,theexhaustgasflowshorizontallyandparalleltoverticalplatesofsheetmetal.Platespacingistypicallybetween19to38cm(9in.and18in.)(_AWMA_,1992).Thehighvoltageelectrodesarelongwiresthatareweightedandhangbetweentheplates.Somelaterdesignsuserigidelectrodes(hollowpipesapproximately25mmto40mmindiameter)inplaceofwire(CooperandAlley,1994).Withineachflowpath,gasflowmustpasseachwireinsequenceasitflowsthroughtheunit.Theflowareasbetweentheplatesarecalledducts.Ductheightsaretypically6to14m(20to45feet)(EPA,1998).ThepowersuppliesfortheESPconverttheindustrialACvoltage(220to480volts)topulsatingDCvoltageintherangeof20,000to100,000voltsasneeded.Thevoltageappliedtotheelectrodescausesthegasbetweentheelectrodestobreakdownelectrically,anactionknownasa corona.Theelectrodesareusuallygivenanegativepolaritybecauseanegativecoronasupportsahighervoltagethandoesapositivecoronabeforesparkingoccurs.Theionsgeneratedinthecoronafollowelectricfieldlinesfromthewirestothecollectingplates.Therefore,eachwireestablishesachargingzonethroughwhichtheparticlesmustpass.Aslargerparticles(>10_m_Ԁdiameter)absorbmanytimesmoreionsthansmallparticles(>1_m_Ԁdiameter),theelectricalforcesaremuchstrongeronthelargeparticles(EPA,1996).Certaintypesoflossesaffectcontrolefficiency.Therappingthatdislodgestheaccumulatedlayeralsoprojectsomeoftheparticles(typically12%forcoalflyash)backintothegasstream.These_reentrained_Ԁparticlesarethenprocessedagainbylatersections,buttheparticles_reentrained_ԀinthelastsectionoftheESPhavenochancetoberecapturedandsoescapetheunit.Duetonecessaryclearancesneededfor_nonelectrified_internalcomponentsatthetopoftheESP,partofthegasmayflowaroundthechargingzones.Thisiscalled _sneakage_andplacesanupperlimitonthecollectionefficiency.Anti_sneakage_Ԁbafflesareplacedtoforcethe_sneakage_Ԁflowtomixwiththemaingasstreamforcollectioninlatersections(EPA,1998).Anothermajorfactorintheperformanceistheresistivityofthecollectedmaterial.BecausetheparticlesformacontinuouslayerontheESPplates,alltheioncurrentmustpassthroughthelayertoreachthegroundplates.Thiscurrentcreatesanelectricfieldinthelayer,anditcanbecomelargeenoughtocauselocalelectricalbreakdown.Whenthisoccurs,newionsofthewrongpolarityareinjectedintothewireplategapwheretheyreducethechargeontheparticlesandmaycausesparking.Thisbreakdownconditioniscalled backcorona.Backcoronaisprevalentwhentheresistivityofthelayerishigh,usuallyabove2x1011ohm " cm.Abovethislevel,thecollectionabilityoftheunitisreducedconsiderablybecausetheseverbackcoronacausesdifficultiesinchargingtheparticles.Low_resistivities_Ԁwillalsocauseproblems.At_resistivities_Ԁbelow108ohmcm,theparticlesareheldontheplatessolooselythatrappingand_nonrapping_Ԁ_reentrainment_ @  becomemuchmoresevere.Hence,caremustbetakeninmeasuringorestimatingresistivitybecauseitisstronglyaffectedbysuchvariablesastemperature,moisture,gascomposition,particlecomposition,andsurfacecharacteristics(_AWMA_,1992)._Precipitatorsizeisrelatedtomanydesignparameters.Oneofthemainparametersisthespecificcollectionarea(SCA),whichisdefinedastheratioofthesurfaceareaofthecollectionelectrodestothegasflow.Highercollectionareasleadtobetterremovalefficiencies.Collectionareasnormallyareintherangeof40to160m2 V"' persm3/secondofgasflow(200-800ft/1000scfm),withtypicalvaluesof80(400)(AWMA,1992). (# (   Advantages:  $t"* DrywireplateESPsandotherESPsingeneral,becausetheyactonlyontheparticulatetoberemoved,andonlyminimallyhinderfluegasflow,haveverylowpressuredrops(typicallylessthan13mm(0.5in.)watercolumn).Asaresult,energyrequirementsandoperatingcoststendtobelow.Theyarecapableofveryhighefficiencies,evenforverysmallparticles.Theycanbedesignedforawiderangeofgastemperatures,andcanhandlehightemperatures,upto700C(1300F).Drycollectionanddisposalallowsforeasierhandling.Operatingcostsarerelativelylow.ESPsarecapableofoperatingunderhighpressure(to1,030kPa(150psi))orvacuumconditions.Relativelylargegasflowratescanbeeffectivelyhandled.(AWMA,1992)  1,)3  & y   Disadvantages:  X   ESPsgenerally'yX`XԀhavehighcapitalcosts.Thewiredischargeelectrodes(approximately2.5mm(0.01in.)indiameter)arehighmaintenanceitems.Corrosioncanoccurnearthetopofthewiresbecauseofairleakageandacidcondensation.Also,longweightedwirestendtooscillatethemiddleofthewirecanapproachtheplate,causingincreasedsparkingandwear.NewerESPdesignsaretendingtowardrigidelectrodes(CooperandAlley,1994).ESPsingeneralarenotsuitedforuseinprocesseswhicharehighlyvariablebecausetheyareverysensitivetofluctuationsingasstreamconditions(flowrates,temperatures,particulateandgascomposition,andparticulateloadings).ESPsarealsodifficulttoinstallinsiteswhichhavelimitedspacesinceESPsmustberelativelylargetoobtainthelowgasvelocitiesnecessaryforefficientPMcollection(CooperandAlley,1994).Certainparticulatesaredifficulttocollectduetoextremelyhighorlowresistivitycharacteristics.Therecanbeanexplosionhazardwhentreatingcombustiblegasesand/orcollectingcombustibleparticulates.Relativelysophisticatedmaintenancepersonnelarerequired,aswellasspecialprecautionstosafeguardpersonnelfromthehighvoltage.DryESPsarenotrecommendedforremovingstickyormoistparticles.Ozoneisproducedbythenegativelychargedelectrodeduringgasionization(AWMA,1992). OtherConsiderations:   Dustswithveryhighresistivities(greaterthan1010ohm-cm)arealsonotwellsuitedforcollectionindryESPs. n Theseparticlesarenoteasilycharged,andthusarenoteasilycollected.High-resistivityparticlesalsoformashlayerswithveryhighvoltagegradientsonthecollectingelectrodes.Electricalbreakdownsintheseashlayersleadtoinjectionofpositivelychargedionsintothespacebetweenthedischargeandcollectingelectrodes(backcorona),thusreducingthechargeonparticlesinthisspaceandloweringcollectionefficiency.Flyashfromthecombustionoflow-sulfurcoaltypicallyhasahighresistivity,andthusisdifficulttocollect(ICAC,1999).@ References:  V AWMA,1992.Air&WasteManagementAssociation,AirPollutionEngineeringManual,VanNostrand  Reinhold,NewYork.Boyer,1999.JamesBoyer,BeaumontEnvironmentalSystems,(724)9411743,personalcommunicationwithEricAlbright,January18,1999.Bradburn,1999.KeithBradburn,ABBEnvironmentalSystems,(800)3468944,personalcommunicationwithEricAlbright,January18,1999.Brown,1999.BobBrown,EnvironmentalElementsCorp.,(410)3686894,personalcommunicationwithEricAlbright,January18,1999.Cooper&Alley,1994.C.D.CooperandF.C.Alley,AirPollutionControl:ADesignApproach,Second $}"* Edition,WavelandPress,Inc.IL.EPA,1996.U.S.EPA,OfficeofAirQualityPlanningandStandards, OAQPSControlCostManual,FifthEdition,EPA453/B96001,ResearchTrianglePark,NC.February.EPA,1997.U.S.EPA,OfficeofAirQualityPlanningandStandards, CompilationofAirPollutantEmissionFactors,VolumeI,FifthEdition,ResearchTrianglePark,NC.,October.EPA,1998.U.S.EPA,OfficeofAirQualityPlanningandStandards, StationarySourceControlTechniquesDocumentforFineParticulateMatter,EPA452/R97001,ResearchTrianglePark,NC.,October. .U,6 ICAC,1999.InstituteofCleanAirCompaniesinternetwebpagewww.icac.com,ControlTechnologyInformationElectrostaticPrecipitator,pagelastupdatedJanuary11,1999.STAPPA/ALAPCO,1996.StateandTerritorialAirPollutionProgramAdministratorsandAssociationofLocalAirPollutionControlOfficials, ControllingParticulateMatterUndertheCleanAirAct:AMenuofOptions,July.