C b ti Additi f SCRCombustionAdditivesforSCRPerformance OptimizationC“ S2012 Power Plant Air Pollutantontrol“Mega”SymposiumBaltimore, Maryland, August 20-23, 2012.1Mandar GadgilAQCS EngineerB&W PGGDerek SilbaughEngineering ManagerBlack Hills CorporationElizabeth HansenBusiness Development ManagerB&W PGGPresentation OverviewPresentationOverviewÌDeactivationbyfluegasconstituentsderivedfromdifferentfuelsÌCombustionadditivedevelopmentdevelopmentÌFieldtestresultsÌEconomicanalysisofcombustiondditii j tiavenecon.2.3Deactivation of SCR Catalyst by ArsenicDeactivationofSCRCatalystbyArsenicÌExperiencedoneasternbituminousandIllinoisBasincoalsÌIndependentofstagedorun‐stagedcombustionClij tiitiÌaciuminecontiesupgasphasearsenic,reducngconcentraonofgasphasearsenicreachingcatalystandtherebytherateofdeactivationofcatalystÌRecommendedcalciumtoarsenicratioissetbasedoncoalbeingfiredÌTrustedmitigationtechniqueusesinjectionofcombustionadditive.4Deactivation of SCR Catalyst by AlkalisDeactivationofSCRCatalystbyAlkalisÌPotassiumandsodiuminducedcatalystdeactivationobservedinbiomasscombustionÌIndependentofstagedorun‐stagedcombustionÌSomewesternbituminouscoalsalsohaveabout1‐1.5%KinashÌNorthDakotalignitehasabout5‐7%NainashÌDeactivationmainlybyreactionbetweenacidsitesoncatalystandK,DeactivationreactionbetweencatalystNaÌStrengthofacidicDeNOxsitesisweakenedbythebaseÌMitigationcouldbepossibleusingcombustionadditives(moredataneeded).5Deactivation of SCR Catalyst by PhosphorusDeactivationofSCRCatalystbyPhosphorusÌDeactivationbyphosphorusmanytimesexperiencedwithPRBcoalÌCombustionconditionsplaymajorroleinthedeactivationprocessÌCommonlyobservedunderstagedcombustionconditionsascomparedtounstaged combustionÌPoorcombustionleadstodeactivationofcatalystbyphosphorusÌGasphasephosphorusatSCRinletisimportantcontributortodeactivationphosphorusimportantcontributordeactivation.6Staged/Poor Combustion EffectsStaged/PoorCombustionEffectsÌCarbothermic reductionofphosphorusbearingminerals‐duetostaginginlowerfurnaceÌEvenunstaged,ifpoorcombustionexistsinfurnacethefurnacesameeffectisobservedÌLoadcyclingwithdifferentmillcombinationinserviceisalsoserviceexpectedtocausecombustionenvironmentsimilartostaging.7Gas Phase Phosphorus SamplingGasPhasePhosphorusSampling80GasPhasePat100%PRBStagedUnits6070

bgasphasePatplantAinletNOx0.22lb/MbtuGaspahsePatWyegnIIinletNOx0.15lb/MbtuGasphasePatPlantAinletNOx0.22lb/MbtuGasphasePatWygen 2inletNOx0.15lb/Mbtu4050

P hase P in pp b2030

Gas P0101234.856789101112RunidDeactivation by Gas Phase PhosphorusDeactivationbyGasPhasePhosphorusÌChemicaldeactivationÌV‐PbondformationindicatedgasphasephosphorusadsorbsonactivesitesjustlikeammoniadoesÌPhosphorusadsorptionmoreprominentonlowerlayers,causingmoredeactivationthanfirstlayer•Inpresenceofammonia,phosphorusadsorptionmaybesuppressed•Secondandthirdlayersseelessammoniathanfirstlayer•accumulationsectionMorePaccumulationatoutletsectionthaninletwithinalog.9Combustion Additive DevelopmentCombustionAdditiveDevelopmentÌB&WinvestigationsforbindingphasephosphorusinvestigationsbindinggasphosphorusÌImpactonboilerperformanceÌTechnicalfeasibilityofinjectionÌShorttermtestingÌLongtermtestingÌInternationalpatentgrantedgÌUSpatentpending.10Long Term InjectionLongTermInjectionÌTodemonstrateareductiondemonstratereductionintherateofcatalystdeactivationÌWygen 2,100MWunitwithSCR,SDAandbaghouseÌWyodak minePRBcoalÌStagedcombustionEi dl tÌxperiencedrapidcataystdeactivationduetophosphoruspreviouslywithnewcatalystAtthtift titl tÌemeoesng,caaystwas6.9mmpitch,singlelayer,regenerated.11Long Term InjectionLongTermInjectionÌCompleted000+ofcontinuousinjectionadditiveCompleted13,hourscontinuousinjectionofadditiveÌPlantcoalflowisaround135,000lbsperhourÌTestinjectionrateofabout50lb/hrÌSimplepneumaticadditiveinjectionsystem.12UsingCombustionAdditiveforSCRCatalystDeactivationMitigationDeactivationMitigation.13Expected Catalyst Performance TrendExpectedCatalystPerformanceTrend1.10 80.910.60.70.8OriginalexpecteddeactivationforWy20 30.40.5y0.6k/ko @16,000hrs0.10.20.3.1400 2000 4000 6000 8000 10000 12000 14000 16000 18000Actual Catalyst PerformanceActualCatalystPerformance1.1Oii ld0 80.91OriginalexpecteddeactivationforWy 20.6k/ko @16,000hrs0.60.70.80 30.40.5ActualdeactivationforWy 20.10.20.30.45k/ko@6,800hrs.1500 2000 4000 6000 8000 10000 12000 14000 16000 18000Wygen2 Catalyst Performance2CatalystPerformance1.1Originalexpected

K o0 80.91OriginalexpecteddeactivationforWy 20.6k/ko @16,000hrs

activity K/ K0.60.70.8

Catalyst0 30.40.5ActualWy 2deactivationwithadditiveActualdeactivationforWy20.10.20.3y0.45k/ko @6,800hrs.1600 2000 4000 6000 8000 10000 12000 14000 16000Wygen2 Performance with Additive2PerformancewithAdditive.17Wygen3 Performance without Additive3PerformancewithoutAdditiveCoalFlowAmmoniaFlowCatalystDP.18ObservationsÌCompleted13,000+hoursofcontinuousinjectionofadditiveÌWithadditiveinjection,therateofdeactivationslowedsignificantlyonastagedcombustionunitÌNonegativeimpactobservedonfurnaceoranyback‐endequipmentÌWorkedwellevenwithregeneratedcatalystÌUniversalapplicabilityindeendentofcatalstteanditchypyyppÌWygen 3withsamecoalandsamestagedcombustionfollowingtypicalSCRdeactivationtrendwithouttheadditiveinjection.19Projections of Catalyst LifeProjectionsofCatalystLifeÌBasedondeactivationrateatWygen 2withadditiveinjection,theprojectedcatalystlifefordifferentscenarios:differentscenarios:UnitNo.oflayersEndoflifeactivityK/KExpectedlifeHyK/KooursWy 3noadditive2 0.43 16,000Wy2withadditive1 0.6 16,000Wy2withadditive2 0.6 24,000Wy 2withadditive3 0.6 36,000ÌSignificantimprovementinlifeofcatalystcanbeachievedduetoslowerrateofdeactivation.20How does a slower rate of deactivation benefit new or existing SCRs?•Extending life further with the same volumeParameterWithadditiveWithoutadditiveUnitsize>650MWe >650MWeInletNOx0.26 0.26OutletNOx0.05 0.05Slip2ppm2ppmInitialvolume680m3680m3Expectedlife26,000 16,000Noofchangeeventsin20years 6 12.21Blended Additive DevelopmentBlendedAdditiveDevelopmentÌDemonstratereductioningasphasephosphorusenteringSCRandsimultaneousincreaseinHgoxidationÌDemonstrateHgemissionscompliancewithoxidationandremovalusingFGDonlyÌDemonstratesameHgoxidationusingblendedpowderadditiveasthatdemonstratedusingliquidbromineÌDevelopedablendedadditive(FeCo3+CaBr2)toachievesimultaneousphosphorusreductionandHgoxidationÌTestedat300MWPRBunitwithSCR,CDSandbaghouseAQCStrain.22Results of Hg Oxidation TestResultsofHgOxidationTestDayAdditivePlantloadCoalHgin%StackStackStackMW lb/Tbtu OxidizedHg@airheateroutletHginlb/TbtuHCl inppmHBr inppmoutlet1 Baseline250 7 30 4.8 0.38 <0.0142 liquidchlorine 250 8.1 51 1.8 0.35 <0.0143 liquidbromine275 13 76 1.1 0.29 <0.0144 powderbromine250 8.5 76 1.2 NA NA.235 powderchlorine150 13 71 1.8 NA NAObservations from Blended Additive TestingObservationsfromBlendedAdditiveTesting3⁄4Overallhigher%Hgoxidationoverbaselineduetohalogeninjection3⁄4Similar%Hgoxidationachievedbybothliquidandpowderedbromineinjection3⁄4Withbromineinjection,stackHgwasatorbelow1.2lb/Tbtu compliancelimitsetbyMATS3⁄4ConfirmsthecapabilitytoachieveHgcomplianceusingSCR,CDSandbaghousewithoutACIinjection3⁄4NoincreaseinstackHCl andHBr emissionsobservedwithinjection.24Economic Benefits of Blended AdditiveEconomicBenefitsofBlendedAdditive3⁄4/SignificantsavingsincompliancecostduetoeliminationreductioninuseofACI3⁄4Asthepoisoningofcatalystismitigated,HgoxidationwithhalogenshouldachieveHgemissioncompliancewithoutcarbonforlongterm3⁄4Additionalrevenuefromsaleofashduetoeliminationofcarbon3⁄4Reductioninashdisposalcostbecauseofashsale.25Questionsmgadgil@babcock.com.26.27