1ComparisonofSodiumBicarbonateandTronaforMulti-pollutantControlYougenKongStanCarpenterSolvayChemicalsInc.ELECTRICPOWER2010Baltimore,MarylandMay18-20,20102Outline•DryInjectionSystem•TronaandSodiumBicarbonate•WhichSorbenttoUse?•Summary3EconomizerAirHeaterBoilerAirTrona/SodiumBicarbonateESP/BagHouseDryInjectionSystem300oF600oF>800oF4TronaApplicationHistory•1965:Tronadrysorbentinjection(DSI)forSO2mitigationatCaliforniaEdison•1970s:PublicServiceofColoradointhe70ssponsoredbyEPRIforSO2mitigation•2001:MoreinterestinsodiumDSIbeganforSO2primarilyatlowsulfurcoalapplications•2002:AEPbeganinvestigatingitsuseforSO3control.–OtherpowerplantshavebeenusingtronaforSO3mitigationsincethen.•Today:ManylocationsusingtronatomitigateSO2,SO3andHCl.5SodiumBicarbonateApplicationHistory•WidelyusedinEuropetoremoveover95%ofSO2and99%ofHCl.•Hasbeenusedinlimitedapplicationsatpowerplants•HavenotachievedwideapplicationsinNorthAmericadueto:–Productavailability–Highcost•SolvayChemicalshasstartedtoproducelow-costsodiumbicarbonatewithapatentedprocessinGreenRiver,Wyoming–Capacity:125,000tons/year.–PhaseII:Another125,000tons/year6TronaSodiumBicarbonateCalcinationat>275oF7ChemicalReactionsNa2SO4,NaClandNaFarecollectedinflyash.•TronaCalcination2(Na2CO3·NaHCO3·2H2O)(s)+heat→3Na2CO3(s)+5H2O(g)+CO2(g)•SodiumBicarbonateCalcination2NaHCO3(s)+heat→Na2CO3(s)+H2O(g)+CO2(g)•AcidNeutralizationReactions–Na2CO3+SO2+1/2O2→Na2SO4+CO2–Na2CO3+SO3→Na2SO4+CO2–Na2CO3+2HCl→2NaCl+H2O+CO2–Na2CO3+2HF→2NaF+H2O+CO28EconomizerAirHeaterBoilerAirSiloMillSodiumBicarbonateESP/BagHouseHandlingSystemsforTronaandSodiumBicarbonateSiloTronaorPre-milledSodiumBicarbonate9>95%Upto90%SO2Removal(%)-Baghouses>90%Upto80%SO2Removal(%)-ESP275~1500oF**275~1500oFFlueGasTemperatureRangeforinjectionNaHCO3Na2CO3.NaHCO3.2H2OFormulaSorbentCostFree-flowingbulkdensity(lb/ft3)ParticleSize:d50(μm)MediumLow6349~100μm~30μmSodiumBicarbonateSOLVAir®Select300*TronaSOLVAir®Select200*Mustbemilledbeforeinjection**Performanceofsodiumbicarbonatemaybrieflydipataround600oF10WhichSodiumSorbenttoUse?Factorstoconsiderwhenmakingchoices:•RequiredSO2removalRate–MoreeconomicaltousesodiumbicarbonateforhighSO2removalrequirements.•ESPorbaghouse–SodiumbicarbonateiseconomicallyfavoredovertronawithESP.Bothareveryeffectivewithbaghouses.•Disposalcostofflyash–Sodiumbicarbonateresultsinlessunusedsorbentandthusfavorediftheflyashdisposalcostishigh.–Sodiumbicarbonateresultsinlowersodiuminflyash•Tronaisready-to-useandsodiumbicarbonateneedstobemilled.–Pre-milledsodiumbicarbonateisavailableathighercosts.11PerformanceComparison:Hot-sideESP01020304050607080901000.00.51.01.52.02.53.03.54.0NSR

S O 2 R e m o v a l R a t e ( % )TronaPre-milledSodiumBicarbonate•Boiler:100MWburninglow-sulfurcoal(SO2:1.2lb/MMBTU)•Sorbentinjectedupstreamofhot-sideESP@650oF.12PerformanceComparison-Cold-sideESP•Boiler:350MWburningCAPPcoal(sulfurcontent:0.85%)•Sorbentinjectedat650oFupstreamofairpreheaterinlet010203040506070809010000.511.522.5NSR

S O 2 R e m o v a l R a t e ( % )Pre-milledSodiumBicarbonateTrona13PerformanceComparison-Baghouse0102030405060700.00.20.40.60.81.01.2NSR

S O 2 R e m o v a l R a t e ( % )SBCTronaUnmilledSBC•Boiler:100MWburninglow-sulfurcoal(SO2:0.59lb/MMBTU)•Sorbentinjectedupstreamofbaghouse@290oF.14EconomicalAnalysisCaseI•100MW•Sulfurcontentofcoal:1.2lb/MMBTUSO2•RequiredSO2removalrate:80%•ESP•Capacityfactor:75%•AnnualOperationCost*:–Trona:$5,000,000–SodiumBicarbonate**:$3,200,000+millingcostChoice:SodiumBicarbonateCaseII•100MW•Sulfurcontentofcoal:0.59lb/MMBTUSO2•RequiredSO2RemovalRate:40%•Baghouse•Capacityfactor:75%•AnnualOperationCost*:–Trona:$670,000–SodiumBicarbonate**:$550,000+millingcostChoice:Trona*Operationcostincludessorbentcostanddisposalcostofunreactedsorbentasflyash**Millsneededforsodiumbicarbonate.Costofmillsnotincluded.15EffectsonHClandSO3•TronaandsodiumbicarbonatearebotheffectiveinmitigationofHCl.•WhilesodiumbicarbonateisaseffectiveinmitigatingSO3astrona,somesodiumbicarbonatewillbeconsumedbySO2duetoitshigherreactivitywithSO2.•GenerallyspeakingtronaismoreeconomicalthansodiumbicarbonateinmitigatingHClandSO3.16Summary•TronahasbeenusedtomitigateSO2fordecades.•Sodiumbicarbonatehasbeenwidelyusedtomitigatemorethan95%ofSO2andover99%ofHClinEurope.•GenerallyspeakingtronaismoreeconomicalforlowSO2removalwithbaghouse,andsodiumbicarbonateisfavoredforhighSO2removalwithESPorbaghouses.•Sodiumbicarbonateismoreeconomicaliftheflyashdisposalcostishigh.•Theneedtousemillsbeforeinjectingsodiumbicarbonateshouldbetakenintoconsideration.–Pre-milledsodiumbicarbonateisalsoavailableifaplantchoosesnottoinstallmillson-site.17Formoreinformation,pleasevisitwww.solvair.usThanks!Questions?