McIlvaine“Hot Topic Hour”HotTopicHourJune 30, 2011Fuel Impacts on Design andPerformance of SCR CatalystsPresenter:John CochranPerformanceofSCRCatalystsCERAM Environmental, Inc.+1 913 239 9896john.cochran@ceram-usa.comCatalyst Deactivates WithTime of Exposure to Flue GasKo (Original Catalyst Activity)

c tivity)Coal/Heavy Pet Coke BlendCoal Low DustCoal High Dust

(Relative A cCoalHighDustBiomassWaste High Dust

K/KoK/Ko @ 16 khr0 2000 4000 6000 8000 10000 12000 14000 16000Operation [hrs]Catalyst Design (at hour=0) Must Anticipate Deactivation to End ofGuarantee Period (e.g., 16,000 hours) to Size Catalyst ProperlyCatalyst Deactivation isVery SiteSpecificVerySiteK/Ko vs Time0 91.00.70.80.9

v ity0.40.50.6

R elative Acti v0.10.20.3

R0.00 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000Hours of SCR OperationVarying Based on Fuel Quality and OperationsVaryingBasedonFuelQualityandOperationsCatalyst Deactivation MechanismsGaseousPoisons:ArsenicPhosphorusPt i A ctivity)Coal/Heavy Pet Coke BlendCoal Low DustCoal High DustPotassiumSodiumCadmiumL d K/Ko (Relative ABiomassWaste High DustLeadCopperOther Elements0 2000 4000 6000 8000 10000 12000 14000 16000Operation [hrs]FoulingbySolid CompoundsGypsum (Calcium Sulfate) and Other Solid Compound DepositionAmmonium Bisulfate (Avoided by Keeping Above PermissiveT t)emperatures)Occurs During...Normal SCR OperationS d Sh d i G h h A id iStartups andShutdowns as UnitGoes ThroughAcidDew PointCatalyst DeactivationVanadiumTitaniaBased Catalyst Deactivates Based on Site Specifics-BasedCatalystDeactivatesBasedonSiteSpecificsFuel Quality – Arsenic, Phosphorus, Potassium, Sodium, Sulfur,Calcium, etc.Comb stion Q alitIncreased S bstoichiometric Staging IncreasesCombustionQuality –IncreasedSubstoichiometricStagingIncreasesQuantity of Gaseous Poisons# of Startups and ShutdownsV diTit iB d C t l t D ti tId d tfanaum-anaBasedCatalystDeactivatesnependento...Catalyst Type – Plate, Honeycomb, Corrugated FiberFormulation – Different Activities and SO2:3 Conversion RatesReference Also “Comparison of Deactivation Rates of DifferentCatalyst Types” by Ed Healy, Southern Company and HansHartenstein, Evonik (now Steag) Presented February 9, 2009h // i h ld i l / bli /47b 6d6 7 8f479388 20d66579738f8/H %20H i %20 ihttp://www.reinholdenvironmental.com/public/47bc6d6a7e8f479388a20d66579738f8/Hans%20Hartenstein%20presentation%20Deactivation%202009.pdfDeactivation Resistance Comes From Providing Adequate ReactorPotential(RP=K/Av)– There Are No Magic Potions)Case Example 1: Two x 500 MW UnitPRB Deactivation Rate HistoryBeing Considered0.91.02 x 500 MW Units - Plate and Honeycomb Catalyst Deactivation Trends0.70.8

c tivity K/Ko0 40.50.6

Relative A c0.30.40 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000Time of Exposure to Flue Gas, hoursOriginal Supplier’s (Plate by Others) Estimate of Deactivation RateU d B i f C t l tD iK/Ko Design Basis of Original Plate SupplierExpected Deactivation TrendUsedasBasisforCatalystDesignCase Example 1: Two x 500 MW UnitPRB Deactivation Rate HistoryBeing Considered0.91.02 x 500 MW Units - Plate and Honeycomb Catalyst Deactivation Trends0.70.8

c tivity K/Ko0 40.50.6

Relative A c0.30.40 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000Time of Exposure to Flue Gas, hoursDeactivation Rate Assumed by Original Plate Catalyst SupplierProven to be OverlyOptimisticK/Ko Design Basis of Original Plate SupplierExpected Deactivation TrendPlate Catalyst Test Results (Original Supplier)ProventobeOverlyOptimisticCase Example 1: Two x 500 MW UnitPRB Deactivation Rate HistoryBeing Considered0.91.02 x 500 MW Units - Plate and Honeycomb Catalyst Deactivation Trends0.70.8

c tivity K/Ko0 40.50.6

Relative A c0.30.40 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000Time of Exposure to Flue Gas, hoursDeactivation Rate Assumed by Original Plate Catalyst SupplierProven to be Overly OptimisticK/Ko Design Basis of Original Plate SupplierExpected Deactivation TrendPlate Catalyst Test Results (Original Supplier)Honeycomb Catalyst Test Results (2 Suppliers)ProventobeOverlyOptimisticSubsequent Replacements With Honeycomb Catalyst From 2Different Suppliers Confirms Both Types Deactivate Based on TheSame TrendCase Example 2: 600 MW Unit BurningEastern Bituminous High Arsenic/Low Calcium Coal0.91Relative Activity Vs Time600 MW Unit With High Arsenic and Low CaOFuels Burned Different Than0 60.70.80.9

K /Ko)Originally Specified Resulting inExtreme Deactivation0 30.40.50.6

e lative Activity ( K00.10.20.3

R eHoneycomb CatalystTest ResultsCorrugated Fiber Catalyst Test ResultsProjected DeactivationExpected Activity for Specified Fuel (16khr)Current Deactivation Trend (16khr)00 5,000 10,000 15,000 20,000Exposure to Flue Gas (hrs)Original Deactivation Rate Underestimated Based on Change in FuelS ifi iSpecificationCatalyst Test Results For Honeycomb and Corrugated Fiber CatalystConfirms Both Types Deactivate Based on The Same TrendWhy is Estimating CatalystDeactivation So ImportantIf Deactivation is UnderestimatedCatalyst is UndersizedI bl f M ti NO R l d A i Sli P fIncapable ofMeetingNOxRemovalandAmmoniaSlipPerformanceat Some Point During the Guarantee PeriodDeficient Performance is Either Tolerated or an Early Outage(Unscheduled) is Required for Catalyst Addition(Unscheduled)isRequiredforCatalystAdditionCatalyst Management Costs are UnderestimatedUnderstanding and Managing ReactorPotential Critical to Minimize RiskPotentialCriticaltoMinimizeRiskExamples Help to Illustrate RiskReactor PotentialCan be represented byP = K/AVK = catalyst activity, Nm3/m2h or Nm/hAV = catalyst area velocity, Nm/h (normalizedoperating gas flow, Nm3/h divided by total installedcatalyst surface area, m2)DeNOx Demand Reactor PotentialDeNOx Demand = The reactor potential requiredto meet NOx removal and ammonia sliprequirementsat the specified operating conditionsatthespecifiedoperatingconditionsCalculatedbased on NOXremoval requirements,NH3slip, SCR distributions, and boiler operatingconditions (flow temperature pressure etc )conditions(flow,temperature,pressure,etc.)Independentof catalyst design life (i.e. same valuefor 16,000 or 24,000 hour catalyst life)Id d tf C t l t T F l tindependentofCatalystType,Formulation, orManufacturerDeNOx Demand, Reactor Potential, & Catalyst Design1. Determine DeNOx Demand (Preq)1. DeNOx demand (Preq) is the amount of reactor potential necessary to achieve NOx removaland ammonia slip performance based on fixed operating conditions (flows temp etc)andammoniaslipperformancebasedonfixedoperatingconditions(flows,temp,etc.DeNOx Demand, Reactor Potential, & Catalyst Design2E ti t C t l tD ti ti (K/K)1. Determine DeNOx Demand (Preq)2.EstimateCatalystDeactivation(Ke/Ko)Varies as Function of Design Life1. DeNOx demand (Preq) is the amount of reactor potential necessary to achieve NOx removaland ammonia slip performance based on fixed operating conditions (flows temp etc )andammoniaslipperformancebasedonfixedoperatingconditions(flows,temp,etc.)2. Catalyst deactivation is estimated based on fuel quality, combustion parameters, and design lifeDeNOx Demand, Reactor Potential, & Catalyst Design3.Determine InitialReactor Potential2E ti t C t l tD ti ti (K/K)3.DetermineInitialReactorPotentialRequired (Po)1. Determine DeNOx Demand (Preq)2.EstimateCatalystDeactivation(Ke/Ko)Varies as Function of Design Life1. DeNOx demand (Preq) is the amount of reactor potential necessary to achieve NOx removaland ammonia slip performance based on fixed operating conditions (flows temp etc )andammoniaslipperformancebasedonfixedoperatingconditions(flows,temp,etc.)2. Catalyst deactivation is estimated based on fuel quality, combustion parameters, and design life3. Based on DeNOx demand and deactivation the initial reactor potential (Po) is determinedDeNOx Demand, Reactor Potential, & Catalyst Design3.Determine InitialReactor Potential2E ti t C t l tD ti ti (K/K)3.DetermineInitialReactorPotentialRequired (Po)4. Determine Catalyst Volumefn(Ko, geometry, SO2:3, gas, etc)1. Determine DeNOx Demand (Preq)2.EstimateCatalystDeactivation(Ke/Ko)Varies as Function of Design Life1. DeNOx demand (Preq) is the amount of reactor potential necessary to achieve NOx removaland ammonia slip performance based on fixed operating conditions (flows temp etc )andammoniaslipperformancebasedonfixedoperatingconditions(flows,temp,etc.)2. Catalyst deactivation is estimated based on fuel quality, combustion parameters, and design life3. Based on DeNOx demand and deactivation the initial reactor potential (Po) is determined4. Catalyst volume is determined based on Po,catalyst activity,geometry,SO2to SO3conversiony,yy, g y,23rate, and various gas conditions and constituentsComparison of Catalyst Design Cases1.6

)Proposal1:'Conservative'DesignCase(0.65K/Ko@16khr)1.4

o r Potential (K/AVRequiredReactorPotentialGuaranteedLife1.2

Relative React o1.0Proposal 1 Has the Most Conservative K/Ko Basis(0.65@16,000 hr)0.80 4000 8000 12000 16000 20000HoursofOperationp(@ )Comparison of Catalyst Design Cases1.6

)Proposal1:'Conservative'DesignCase(0.65K/Ko@16khr)Proposal2:'Aggressive'DesignCase(0.72K/Ko@16khr)Variance inReactorPotentialConsistsofVolume,SurfaceAreaand/orKDifferences1.4

o r Potential (K/AVRequiredReactorPotentialGuaranteedLifeAreaand/orKDifferences1.2

Relative React o1.0Proposal 2 is Based on a More Aggressive Deactivation Rate(0.72 K/Ko)0.80 4000 8000 12000 16000 20000HoursofOperationp gg ()Approximately 10% Difference in Catalyst VolumeWho is Right?Case A: Proposal 1 Deactivation Rate Correct1.6

)Proposal1:'Conservative'DesignCase(0.65K/Ko@16khr)Proposal2:'Aggressive'DesignCase(0.72K/Ko@16khr)1.4

o r Potential (K/AV0.72K/KoBasedProposal2Operatingat0.65K/Ko@16khrRequiredReactorPotentialGuaranteedLife1.2

Relative React o1.0ReducedCatalystLifeSinceProposal2WasUndersizedShould a K/Ko of 0.65 ActuallyOccur Proposal 2 Would be Undersized0.80 4000 8000 12000 16000 20000HoursofOperationy pand Meet Performance for Less Than 11,000 HoursEarly Outage Required or Reduced Performance Must be AcceptedCase B: Proposal 2 Deactivation Rate Correct1.6

)Proposal1:'Conservative'DesignCase(0.65K/Ko@16khr)Proposal2:'Aggressive'DesignCase(0.72K/Ko@16khr)1.4

o r Potential (K/AV0.65K/KoBasedProposal1Operatingat0.72K/Ko@16khrRequiredReactorPotentialGuaranteedLife1.2

Relative React oIncreasedCatalystLife1.0Should a K/Ko of 0.72 ActuallyOccur Proposal 1 Would be Oversized0.80 4000 8000 12000 16000 20000 24000 28000HoursofOperationy pand Meet Performance for More Than 24,000 Hours (>3 Years)Catalyst Management Costs Greatly ReducedUnstaged PRB Fired Units Catalyst DeactivationGroup 1: PRB Unit Catalyst Activity Test Results1.01.20.60.8

t ive Activity K/Ko0.20.4

Rela0.00 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000Exposure to Flue Gas, hoursPlant 7 PCPlant 8 PCPlant 9 CyclonePlant 10 PC“Unstaged” PRB Units Indicate a K/Ko@16,000 hours of 0.6 to 0.8Plant9CyclonePlant10PCPlant 11 PCPlant 12 CyclonePlant 13 CyclonePlant 14 CycloneGeneral Deactivation Trend - Unstaged PRB Unitsg@Wide Variation of Results Dependent on Many Operations and FuelVariablesCatalyst Deactivation for "Deeply Staged" PRB UnitsGroup 2: PRB Unit Catalyst Activity Test Results1.01.2

oCatalystDeactivationfor"DeeplyStaged"PRBUnits0.60.8

a tive Activity K/K0.20.4

RelPlant 1 PCPlant 2 PCPlant 3 CyclonePlant 4 CyclonePlant 5 CyclonePlant 6 PCOther DeeplyStaged General TrendPlant 6 PC General Trend0.00 5,000 10,000 15,000 20,000 25,000Exposure to Flue Gas, hourspy gCombustion Conditions Greatly Affect PRB Application Deactivation RatesCombustionConditionsGreatlyAffectPRBApplicationDeactivationRatesBroad Consensus of Results for “Deeply Staged” Units Confirm Severe DeactivationHighly Risky if Plant 6 Alone Was Selectedas a Reference Unit to Support Proposal SizingA Plant 6 Based Catalyst Design Will Last Less Than One Year on a 24,000 Hour Guarantee WithgDeep Deactivation Seen for Broader ExperienceSummaryDeactivation Rates Vary Widely Dependent on Site SpecificsFuel Quality, Combustion Parameters, and Boiler Duty Cycle GreatlyAffect Catalyst Deactivation RatesVanadium-Titania Based Catalysts All Deactivate at the Same Rate Based onSite SpecificsUnderestimating or Aggressive Sizing Compromises SCR Performance andUnderestimatingorAggressiveSizingCompromisesSCRPerformanceandEffective Catalyst ManagementRisk of Early Outage for Catalyst AdditionsRisk of Deficient PerformanceInitial SCR Project Design Should Carefully Consider Reactor Potential toDetermine the Risk Profile of Various ProposalsAggressive Catalyst Designs Can Result in Operations Difficulties andIncreased Cost