German Experience withCatalyst RegenerationHans HartensteinSTEAG LLC2007 NOx Round Table and ExpoFebruary 5 – 6, 2007Cincinnati, OhioSTEAGSCR Catalyst Regeneration Nomenclature●Cleaning = Removal of physical restrictions such asblinding layers and large particle ash –can be done on-site as well as off-site.●Rejuvenation = Removal of catalyst poisons without theneed for replenishing catalytically activecompounds – can sometimes be done insitu, but is most commonlydone either on-site or off-site.●Regeneration = Removal of catalyst poisons plusrestoration of catalytic activity byaddition of catalytically active ingredients– can typically not be done in-situ or onsite, but should be done off-site to ensurerequired close process control.NomenclatureSTEAG‘s BergkamenPower StationSTEAG‘s FenneCogeneration PlantSCR Catalyst Regeneration History●1983: Legislation – Flat rateNOx emission limit of 200mg/Nm3(~100 ppm) for all units≥~100 MWregardless of age, fuel and capacity factor●Mid to late 1980’s: SCRS wereinstalled on practically fossilfuel fired units in Germanyto meet new legal emissionrequirements●Mid to late 1990’s:•Catalyst deactivation by plugging and catalystpoisons became a greater concern as the use of worldmarket coal and “secondary fuels” increased•Buying new catalyst was economically unfavorable inlight of deregulation and increasing catalyst cost•Several utilities includingEnBW, HEW, SBW/STEAGbegan R&D on catalyst cleaning and rejuvenationKey EventsSTEAG‘s BexbachPower StationSTEAG’s WeiherPower StationSCR Catalyst Regeneration History●1995/1996: STEAG starts developing an on-site techniquefor LPA removal after Voerde’s 760 MW Units 3and 4 have major LPA problems and 4honeycomb layers plug as a result of switchingfrom indigenous to world market coal.●1996/1997: SBW (now STEAG) develops a patented on-siteprocess for the removal of surface blindinglayers and rejuvenation after a coal switch fromGöttelborn to Ensdorf coal (Saar regional mine)caused the formation of strong surface blindinglayers at Bexbach’s 780 MW Unit 1 and Weiher’s725 MW Unit 3 due to highCaO content in the flyash (similar to PRB) .●1996/1997: EnBW develops a simple in-situ process for theremoval of ordinary fly ash pluggage and partialrejuvenation at the Power Plant Heilbronn.Key EventsEnBW‘s HeilbronnPower StationSTEAG’s VoerdePower StationSCR Catalyst Regeneration History●1997/1998: SBW/STEAG perform first full-scalerejuvenations at Bexbachand Weiher (removal ofblinding layers and mild catalyst poisons) andcleaning at Voerde (removal of LPA pluggage).●1997: STEAG’s Leuna Cogeneration Plant burning100% refinery residue including pet coke startsup with all 3 units having high-dust SCRs, whichrely on regeneration for economicallysustainable SCR operation.●1997/1998: HEW develops an on-site process for the removalof ordinary fly ash pluggage and rejuvenation atthe Tiefstack Cogeneration Plant.●1998/1999: Integral developsan on-site cleaning andrejuvenation process at acoal- and oil-fired plantfor the removal of vanadium blinding (oil-firedunit) and mild catalyst poisons (coal-fired unit).Key EventsHEW‘s TiefstackCogeneration PlantSCR Catalyst Regeneration Processes●BHK Process:•On-site process, which was used once at E.ON’s MehrumGenerating Station for one layer of BHK plate catalyst.•Process seems to be no longer marketed in Europe sinceno other known applications in Europe are known.●EnBW’s In-situ Rejuvenation Process:•Process was further refined and optimized withoutovercoming its limitations ofbeing performed in-situ,which is also its main advantage.•Still used in house within the EnBW/EDF group.•Technology sold to CESI/SCR-Tech for use in NorthAmerica and to Envica/EKS for use elsewhere.●Envirgy Process:•Spun off of Integral in late 2002.•Developed a cleaning process in 2003 together withEnerfab who markets the process in North America.RegnerationProcessesEnBW‘s In-situRejuvenation ProcessSCR Catalyst Regeneration Processes●HEW Process:•HEW and SAS founded KAS to further develop andmarket the HEW process forcleaning, rejuvenation andregeneration.•HEW sold its 50% share in KAS, (renamed Envica andlater EKS) now markets the technology except for inNorth America where it was sold to CESI/SCR-Tech.●Integral Process:•Process is being successfully marketed throughoutEurope and Asia after further process refinements.●KWH Process:•KWH developed a regeneration process in 2002/2003.•Process was used a few times in Germany but seems tohave disappeared from the market with the sale andmove of KWH to China.RegnerationProcessesHEW‘s On-siteRejuvenation ProcessIntegral‘s On-siteRejuvenation ProcessSCR Catalyst Regeneration Processes●STEAG/SBW Process:•Steag acquired SBW and obtained a license from IntegralUmwelttechnik GmbH, Austria for STEAG’s fleet andfor North America.•Merged technologies, know-how and experience for thedevelopment of a significantly optimized process.•Used up to now for in house rejuvenation andregeneration only.•On-site process for cleaning and rejuvenation.•Off-site process for cleaning, rejuvenation andregeneration.•Marketed in North Americaexclusively by STEAG sincelate 2006.•STEAG’s off-site regeneration facility will commenceoperation in Kings Mountain, North Carolina in summer2007.RegnerationProcessesLPA Plugged Catalyst– STEAG‘s VoerdePower StationRejuvenated Catalyst– STEAG‘s VoerdePower StationSTEAG’s Catalyst Regeneration Needs●STEAG developed a regeneration process due to:•Perpetually frequent need for•Ca-based blinding layer removal and rejuvenation ofthe Bexbach, Fenne and Weiher catalyst.•Rejuvenation of V-based blinding layer removal andreduction of SO2/SO3conversion rate of the catalystof the Leuna and Godorf refinery units (same type offuel, high-dust SCRs).•A more cost effective process for odd size modules.•Bexbach (9 x 18 log honeycomb modules)•Fenne (24 box triple-decker plate modules)•Weiher (6 x 6 log honeycomb modules)•Rapidly growing regeneration needs within STEAG’sfleet of currently 24 (soon 26) SCRs due to increaseduse of world market coals and secondary fuels(sewage sludge, bone meal, pet coke, etc.).RegenerationNeedsWeiher 6 x 6 LogHoneycomb ModulesFenneTriple-decker PlateModulesBexbach, Weiher and Fenne – Blinding Layers●A coal switch to Ensdorf coalcaused rapid deactivation dueto unknown causes at the time.●The formation of a very strongsurface blinding layer mostlyconsisting of CaSO4and fly ash was found to be the cause.●Ensdorf coal with a CaO content in the fly ash of around10%wt. was determined to be the source.●A patented, DI-water based rejuvenation process wasdeveloped and has been successfully applied to all catalystlayers at Bexbach, Fenne and Weiher since 1997.●Since then the same catalyst layers have been successfullyrejuvenated up to 3 times.STEAG’s BexbachPower StationSTEAG’s WeiherPower StationBlinding LayersWeiher Power Station Unit 3- 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000SCR operating hours

DeNOx potential PAdditionof newhoneycomblayer D.Removal oflayers A, C toregeneration,addition ofregeneratedlayer A.4.2FFF (new)DD (reg)DDD (new)4.13.2EEEE (new)AAA (reg)C3.1B2.2DD (reg)CCCC (reg)B2.11.2A (reg)BBBB (reg)A1.1layer72,00061,52650,56045,85342,62736,68132,86826,631Removal oflayer B toregeneration,addition ofregeneratedlayer C.Addition ofregeneratedlayer B,regenerationof layer D.Removal oflayer A toregeneration,addition ofnew honeycomb layer E.Removal oflayer D toregeneration,addition ofnew honeycomb layer F.Removal oflayer C toregeneration,addition ofregeneratedlayer D.Bexbach, Weiher and Fenne – Blinding LayersSTEAG’s WeiherPower StationRegenerated Weiher6 x 6 Log HoneycombModulesRegenerationExperienceSTEAG’s Catalyst Regeneration Experience●STEAG’s regeneration processdevelopment was driven by:•Need for higher activity gains than possible throughrejuvenation only.•More than 2 – 3 rejuvenations are not cost effective asthe incremental gain in activity declines below theeconomic threshold. Full regeneration is needed.RegenerationExperienceRejuvenation Tank atWeiher Power StationRejuvenation Bexbach Layer C010203040500 10,000 20,000 30,000 40,000 50,000activity [m/h]

layer C operating hoursRejuvenation TankDuring CatalystLoadingLeuna and Godorf – Vanadium Pore Pluggage●High-dust SCR in combinationwith the refinery residue fuel(S≤6%wt.) highly problematic.●Very rapid deactivation at times,highly dependent on fuel mix.●The formation of a very strong pore pluggage mostlyconsisting of vanadium and fly ash as well as poisoningdepending on fuel composition was found to be the cause.●Unit operation would beuneconomical withoutcatalyst regenerationdue to highly variablecatalyst exchangefrequencies and cost.LeunaCogeneration PlantLeuna Units 1, 2 and 3- 10,000 20,000 30,000 40,000 50,000 60,000 70,000SCR operating hours

DeNOx potential PP U1P U2P U3STEAG’s LeunaCogeneration PlantSTEAG’s GodorfCogeneration PlantG used elsewhereA, DA, FHEBA, BAFCout for regen.CCC (reg)HHHHH (new)FFEEE (reg)CCCCC (reg)EEU3HH (reg)FFFFF (reg)DDDII (new)AAA (reg)GGGG (new)CU2F (reg)DDDDD (reg)BBBBBBBB (reg)EEEE (reg)AAU167,00062,25656,19854,57040,47037,77233,99432,81330,1780hoursG used elsewhereA, DA, FHEBA, BAFCout for regen.CCC (reg)HHHHH (new)FFEEE (reg)CCCCC (reg)EEU3HH (reg)FFFFF (reg)DDDII (new)AAA (reg)GGGG (new)CU2F (reg)DDDDD (reg)BBBBBBBB (reg)EEEE (reg)AAU167,00062,25656,19854,57040,47037,77233,99432,81330,1780hoursSTEAG’s Catalyst Regeneration Experience●STEAG’s regeneration processdevelopment was driven by:•Suspicions of increases in SO2/SO3conversion ratewhen regenerated by commercial regeneration vendors.RegenerationExperienceBergkamen Vendor Regeneration Honeycombs0%50%100%150%200%K0 Kreg KSO2/SO30 KSO2/SO3regSTEAG‘s BergkamenPower StationSTEAG‘s BergkamenPower StationSTEAG’s Catalyst Regeneration Experience●Further investigation confirmed the problem:•Other utilities reported similar observations.•Unwanted and/or unpredictable increases wereconsidered very undesirable for STEAG’s SCRs.Voerde Vendor Regeneration Honeycombs0%50%100%150%200%250%300%350%K0 Kbefore reg Kreg KSO2/SO30 KSO2/SO3before regKSO2/SO3regRegenerationExperienceSTEAG’s VoerdePower StationSTEAG’s VoerdePower StationSTEAG’s Catalyst Regeneration Experience●STEAG’s regeneration process was benchmarked againstcommercial regenerators in Europe:•R&D was focused on getting the SO2/SO3conversionrate under control while regaining full activity.RegenerationExperienceComparative Testing Vendor Process Versus STEAG Process0%50%100%150%200%250%K0 Kbefore reg Kreg KSO2/SO30 KSO2/SO3before regKSO2/SO3regSTEAGVendorBefore TreatmentDuring TreatmentSTEAG‘s Patented Regeneration Technology●STEAG’s patented regeneration technology is based oneffective:•Removal of physical restrictions (fly ash and LPA).•Removal of catalyst poisons (As, P, Na, K, CaSO4, etc.).•Protection of components essential for maintaining thecatalyst’s structural integrity and mechanical strength(i.e. WO3).•Full activity restoration through replenishment of thecatalyst’s active components (V2O5, MoO3, WO3).•Recalcination for best impregnation success andmechanical strength protection.CatalystRegenerationReceiving / WarehouseDry and/or Wet CleaningChemical TreatmentUltrasonic TreatmentIon Mobilization and EliminationPreconditioning for ImpregnationSelective Catalytic ImpregnationDrying and RecalcinationQA/QC InspectionPackaging / Warehouse / DeliverySTEAG’s CatalystRegenerationProcessSTEAG’s Patented Processes(continued)●Developed patented processes that are fully flexible:•Dry and/or wet mechanical cleaning (as needed).•Multi-stage wet chemical treatment for poison removal.•Ultrasonic cleaning (only ifneeded and appropriate).•Ion mobilization, elimination and preconditioning forimpregnation.•Selective replenishment of V2O5, MoO3, and WO3asneeded (in case of full regeneration only).•Multi-stage drying.•Recalcination (only in case of regeneration needed).•Repair of mechanical (e.g. erosion) damage (if needed).•Packaging.CatalystRegenerationSTEAG’s CatalystRegenerationProcessReceiving / WarehouseDry and/or Wet CleaningChemical TreatmentUltrasonic TreatmentIon Mobilization and EliminationPreconditioning for ImpregnationSelective Catalytic ImpregnationDrying and RecalcinationQA/QC InspectionPackaging / Warehouse / DeliverySTEAG’s Catalyst Regeneration●Technology based:•Experience and own know-how developed since 1997●STEAG’s own patents (German and U.S.)•Use of DI-water for cleaning, rejuvenation andregeneration.•Aeration of vat during treatment.•Reduction of SO2/SO3conversion rate.•Selectively distributive replenishment of catalyticallyactive ingredients.●STEAG owns a license forthe process developed byIntegral Umwelttechnik, Austria including use of theirpatents for STEAG’s own SCR fleet and in North America.CatalystRegenerationSTEAG’s CatalystRegenerationProcessSTEAG’s Patentsfor CatalystRegenerationSTEAG‘s Regeneration Experience●Experience gained and regeneration performancewas tested and verified within our own pool ofalmost 10,000 m3of SCR catalyst.•3,220 m3for STEAG’s SCR fleet in Germany•Single layers regenerated up to 4 times•680 m3for various third parties in Europe●Some of STEAG’s SCRs depend and solely rely onsuccessful catalyst regeneration for adequate SCRoperation and economical unit operation, e.g. Leunaand Godorf Cogeneration Plants.CatalystRegenerationSTEAG’s Patentsfor CatalystRegenerationSummary andConclusionsSummary and Conclusions:●Catalyst is viewed and treated by STEAG as a commodity,however not all catalyst types are suitable for allapplications.●Each type of catalyst hasits distinct advantages anddisadvantages. The selection of the best catalyst typerequires an economic evaluation on a case by case basis.●The use of new versus regenerated catalyst depends solelyon market conditions and prices. The prices of regeneratedcatalyst varied between 25% and 65% of new catalyst,depending on the price of new catalyst and the type ofregeneration process used and required.●As other German utilities, STEAG also found no differencein longevity or deactivation rate between regenerated andnew catalyst. However, the SO2/SO3conversion rate differssignificantly, depending on the regeneration process used.STEAG’s HerneCogeneration PlantSTEAG’s WalsumCogeneration PlantSTEAG’s catalystregeneration:10 years ofin-houseexperience?Questions?STEAG