AmmoniaAdsorption.pdf

7/30/2019 AmmoniaAdsorption.pdf

1/16

White Paper | Confidential and Proprietary | February 2012

Ammoniaadsorptiononash

PenelopeStamatakis,PhD

Introduction

TherearetwoprimarypostcombustiontechnologiesthatreduceNOxviatheintroductionofan

aminebasedreducingagent,namelySelectiveNonCatalyticReduction(SNCR)andSelective

CatalyticReduction(SCR).Ammoniaslipisaby-productofbothofthesetechnologiesandit

referstoammoniainthegaseousphase,typicallymeasuredattheeconomizeroutletusingEPA

methodCTM-027.Thecontrolofammoniaslipisanintegralpartoftheoptimizationphasein

anySNCRorSCRapplication.Thegaseousammonialeftuncontrolled,hasthepotentialto

combinewithSO3inthefluegasandformundesirableammoniumbisulfatedepositsonmetal

surfaces.Additionally,dependingontheashproperties,asignificantamountoftheammonia

slipmaybeadsorbedontheash.Typically,ammoniaisadsorbedontheasheitherchemically,

viatheformationofammoniumsulfateandbisulfatesaltsontheash,orphysically,onunburned

carbonsurfaces.Thisbecomesaproblemforclientswhoselltheirashtothecementindustry,

sinceduringthemakingofconcrete,ammoniamaybereleasedfromtheashasthepHincreases

duetotheadditionoflime.Releasedammoniagivesoffauniqueodorwhichisdetectableby

smellifthelevelsofammoniaontheflyashexceedtherangeof50to100mg/kg.Utilitiesthat

employFuelTechsSNCRandSCRtechnologiesroutinelyaskfortheexpectedlevelofammonia

ontheflyash.Thisstudywilladdressthisquestionbylookingatammoniaadsorptiononthe

ashasafunctionofcoaltypeandashpropertiesanddevelopamethodologytopredictammonia

adsorptiononash.

Background

Duringthecombustionofsulfur-containingfuels,over95%ofthesulfurisconvertedtosulfur

dioxide.Subsequently,morethan1%ofthesulfurdioxidemaybefurtheroxidizedtosulfur

trioxide.(Ref.1)Sulfurtrioxidehasthepotentialtocombinewiththeammoniaslipgenerated

viatheSNCRandSCRprocessesandformammoniumsulfateandammoniumbisulfatesalts.

Ammoniumbisulfateformsasaliquidwhichmaydepositoncoldmetalsurfacesthatare

maintainedattemperaturesbelow360oF.Ammoniumsulfateisapowderysubstancewhich

formsattemperaturesbelow410oF.(Ref.2)Bothofthesespeciescandepositontheflyash.

CoalashwithhighcalciumcontentsuchasPRBashexhibitshighalkalinityandassuchithasa

lowaffinityforcapturingammonia.Easternbituminouscoalhasaverylowalkalinityashwhich

actsasanammoniasponge.Notallthegaseousammonia,however,willadsorbontheash,

sinceaportionoftheammoniamayalsocombinewithSO3inthefluegasandformammonium

bisulfatedepositsoncoldmetalsurfaces.AstudycarriedoutbySouthernCompanyusinghighS

coalsuggeststhatabout30%oftheammoniaslipgeneratedfromanSNCRorSCRprocess

becomestiedupinammoniumsulfateandbisulfatedepositsoncoldmetalsurfaceswhile70%is

availabletotheflyash.(Ref.3)Lessthan1%oftheammoniaslipwillmakeittothestack.

Clearly,theresultsofthisanalysisdependontheoperatingconditionsduringthestudy,butthey


2/16


giveanindicationfortheaffinityofflyashtoammoniawhenfuelswithhighScontentareused.

AshgeneratedbyPRBcoal,whichhashighalkalinity,haslowpotentialforadsorbingammonia.

Inaddition,duetothelowSO3concentrationinthefluegas,ammoniumsulfateandbisulfate

formationwillbefairlylowaswell,andassuch,mostoftheammoniaslipwillgoupthestack.

Thisnumberisnotknownexactly,butthisanalysiswillassumethataminimumof70%ofthe

generatedammoniaslipunderPRBcombustionwillbereleasedfromthestackandonly30%will

beavailableforadsorption.Itisworthnoting,however,thatammoniacanstillabsorbonthe

unburnedcarbonasdemonstratedbyFuelTechsstudiesatNipscosBailly#8,eveniftheashhas

lowaffinityfortheammonia.(Ref.4)

Manyutilitiesselltheirashtothecementindustry.Cementcontainshighquantitiesoflime,and

asitishydratedtomakeconcrete,itsalkalinityincreases.Thishighalkalinitycausestherelease

ofammoniafromtheconcrete,andalthoughitdoesnothaveanynegativeimpactonthepropertiesoftheconcrete,itcausesanodorwhichisunacceptabletoboththeconcrete

manufactureraswellastheconcreteenduser.(Ref.5)Ingeneral,thelimitssetbythecement

industryontheacceptablelevelofammoniaonashareinthe50to100mg/kgrange.Inorderto

keepthisconcentrationlow,theammoniainthegasphaseneedstobelimitedinthe2to5ppm

range.

In1993,FuelTechbrieflyconsideredtheconceptofthermallytreatingtheashtostripthe

ammonia.Duringthistime,preliminaryanalyticalworkshowedadirectcorrelationbetweenthe

alkalinityoftheashandtheamountofammoniaadsorbed.Itwasrecognized,however,that

moreandmoreutilitiesstartedburningPRBcoalwhichgeneratesashthathaslowaffinityfor

ammonia,andtheideawasabandoned.(Ref.6)

Analysis

ThefluegasflowgeneratedbycombustioncanbecalculatedonthebasisoftheoperatingO2,

theamountoffuelburned,thehigherheatingvalueofthefuel,andtheFdfactorwhichisfuel

specificandindicatesthedryfluegasthatisgeneratedforeveryMMBtuoffuelburnedasshown

bytheequationbelow:

Fluegas(dscfh)=Fd(dscf/MMBtu)*HHV(Btu/lb)*10-6MMBtu/Btu*Fuel(lb/hr)*20.9/(20.9-O2)(1)

Ammoniaslipgeneratedinthegasphaseistypicallyexpressedinpartspermillion,ppm,andrepresentsthemolesofammoniapermoleoffluegasmultipliedbyonemillion.

NH3slip(ppm)=[NH3(moles/hr)/Fluegas(moles/hr)]*106(2)


3/16


SincethemolecularweightofNH3is17,themolarflowofammoniacanbecalculatedby

dividingthemassflowby17.Similarly,themolarflowofthefluegascanbederivedbydividing

thevolumetricflowby385.4,where385.4comesfromtheidealgaslawandindicatesthe

volumeoffluegasoccupiedbyonemoleoffluegasunderstandardconditionsoftemperature

andpressure.Equation(2)canthereforeberewrittenasfollows:

NH3slip(ppm)=[{NH3(lb/hr)/17(lb/mol)}/{Fluegas(dscfh)/385.4(dscf/mol)}]*106(3)

AssumingatypicaloperatingO2of3%andcombiningequations(1)and(3),themaximum

ammoniageneratedin(lb/hr)is:

NH3(lb/hr)=NH3slip(ppm)*0.0515*Fd(dscf/MMBtu)*HHV(Btu/lb)*Fuel(lb/hr)(4)

Theammoniaconcentrationontheashistypicallyexpressedonagravimetricbasisorppm-w.

Thisunitisequivalenttomgofammonia/kgofashorlbofammonia/lbofashdividedbya

million.

NH3onash(ppmw)=[NH3(lb/hr)/Ash(lb/hr)]*10-6(5)

Assumingthat80%oftheashbecomesflyash,theaboveequationcanberewrittenasfollows:

NH3onash(ppm-w)=[NH3(lb/hr)/{%Ash*Fuel(lb/hr)*0.8}]*10-6(6)

Itshouldbenotedthatforcyclonefiredunitsonly40%oftheashbecomesflyashwhileforwet

bottomunitsthisnumbermaybecloserto25%.

Ifalltheammoniaslipisadsorbedontheashandbycombiningequations4and6,themaximum

concentrationofammoniaontheashwouldbe:

NH3onash(ppm-w),maximum=[NH3slip(ppm)*0.0644*Fd*HHV/%Ash]*10-6(7)

Ifanadsorptionrateisestablished,thentheammoniaontheashofaspecificcoalcanbe

calculatedasfollows:

NH3onash(ppm-w)=Adsorption(%)*NH3onash(ppm-w),maximumor(8)

NH3onash(ppm-w)=Adsorption(%)*[NH3slip(ppm)*0.0644*Fd*HHV/%Ash]*10-6(9)

EPRIhascarriedoutseveralstudiesinanefforttoinvestigateammoniaadsorptiononflyashfor

variouscoals.FuelTechwillutilizethemeasuredammoniaonashforeachofthecasesstudied


4/16


byEPRIandwilldeterminethe%adsorptionforeachcoalfromtheratioofthemeasured

amountofadsorbedammoniaandthemaximumamountofammoniaavailableforadsorption.

TheEPRIstudyfocusedontheashcollectedfromthefollowing8sites(Ref.7):

TABLEI:Testsites

Utility Station Unittype Coalrank

Ameren Baldwin Cyclone Bit.,hvC

GeorgiaPower Bowen#3 T-fired Bit.,hvB

AEP CardinalI Wallfired Bit.,hvB

SRIcombustor LoneMountain Wallfired Bit.,hvA

AlabamaPower Miller#3 Wallfired PRB

WEPCO PleasantPrairie Wallfired PRBAmeren SiouxI Cyclone PRB/Bit.hvC

SouthernPower Stanton Wallfired Bit.,hvA

TheflyashsamplesfromeachsitewerecollectedfromvariousESPhoppers.(Ref.6)Allthe

samplesfromaspecificsitewereblendedtogether,andtheanalysiswasdoneonthisblended

sample.TheammoniaadsorptionontheflyashwasmeasuredbyWashingtonsUniversityinSt.

LouisAirQualityLaboratory.Theexperimentconsistedofexposing1gramoftheblendedflyash

samplefor30mintoafluegasconsistingof14%CO2,4%O2,10%H2O,500ppmSO2,15ppmof

NH3andthebalancewasN2.Thefluegastemperaturewasmaintainedat325oFandthefluegas

flowwas500accm.Fromtheammoniaflow,fluegasvolume,andtheexposuretime,itwasdeterminedthatthemaximumgravimetricamountofammoniathatcouldhavebeenproduced

is0.106895mg.Ifallthisammoniaisadsorbedonthe1gofflyash,themaximumamountof

ammoniaonashwouldbe106.9mg/kg.Thetablebelowsummarizestheactualamountof

ammoniaadsorbedontheashforalltheapplicationsasmeasuredbytheAirQualityLaboratory.

Inaddition,itcomparesthisvaluetothecalculatedvalueof106.9mg/kgandtakestheratio.

Thisratioshowsthepercentofammoniaactuallyadsorbedontheashoutoftheamountthatis

theoreticallyavailableforadsorptionandisindicativeofthepotentialforadsorptionofammonia

onflyashforvariousfuels.

TABLEII:AmmoniaAdsorptiononFlyAshFixedExposure

Utility StationNH3

Adsorbed(mg/kg)

NH3

Adsorbed(%)

Ameren Baldwin 92 86

GeorgiaPower Bowen#3 60 56

AEP CardinalI 90 84

SRICombustor LoneMountain 128 100*

AlabamaPower Miller#3 15 14


5/16


WEPCO PleasantPrairie 16 15

Ameren SiouxI 81 76

SouthernPower Stanton 110 100*

The*denotesthatmeasuredvaluewashigherthanwhatwastheoreticallyavailableandfor

thesecasesitwasassumedthat100%oftheammoniawasadsorbed.Theaboveresultsshow

thattheashfromMillerandPleasantPrairieexhibitedtheleastamountofammoniaadsorption

whileflyashfromLoneMountainandStantonStationexhibitedthehighestamountofammonia

adsorptionontheash.ItisworthnotingthatMillerandPleasantPrairieburnPRBcoalwhile

loneMountainandStantonburnhighvolatilitybituminousA.

Theobjectiveofthisanalysisistobeabletocorrelatetheadsorptionpotentialwithspecificcomponentsoftheflyashorthefuel.FuelTechlocatedthefuelanalysisandashanalysisforthe

aboveapplicationswiththeexceptionofBowen#3.(Ref.9to11).PlantBowenisnotspecifically

includedinthisdiscussion,althoughthegeneralstatementcanbemadethatforthisbituminous,

highvolatilityBcoal,therateofadsorptionexceeds50%.Finally,SiouxStationusedablended

coal,andtheanalysisisbasedonan83%Caballoand17%Illinois#6(2)coal.

TABLEIII:Fuelanalysis

Weight(%)

Moistureand

ashfree

Baldwin Cardinal Lone

Mountain

Miller Pleasant

Prairie

Sioux

Stanton

C 78.9 84.1 87.84 74.8 74.94 75.6 83.27

H 5.5 5.6 5.43 5.37 5.27 5.3 5.53

O 10 4.96 4.23 18.4 18.34 1.14 8.4

N 1.38 1.53 1.58 0.96 1.07 1.13 1.6

S 4 3.86 0.93 0.46 0.38 1 1.08

HHV(Btu/lb) 12233 13859 15243 13032 14061 13750 13254

Fd(dscf/MMBtu) 11328 10755 10035 9661 8945 9305 10904

Theashanalysisfortheabovefuelsistabulatedbelow:

TABLEIV:Flyashcomposition

Constituents Baldwin Cardinal Lone

Mountain

Miller Pleasant

Prairie

Sioux

*

Stanton

SiO2(%) 48.91 39.65 55.83 27.8 31.9 34.79 58.2

Al2O3(%) 18.26 19.68 28.67 13.1 16.9 17.13 30.67

Fe2O3(%) 18.06 27.79 7.58 5.5 5.6 7.72 4.88

TiO2(%) 0.88 0.85 1.29 1.3 1.4 1.31 2.08

CaO(%) 4.82 4.54 2.56 26.6 24.7 21.32 1.16


6/16


MgO(%) 1.04 0.85 1.64 7 4.6 3.99 0.42

Na2O(%) 1.03 0.9 1.0 1.3 1.4 1.34 0.17

K2O(%) 2.1 1.21 2.23 0.3 0.3 0.61 0.99

SO3(%) 4.68 4.18 1.5 16 12.2 10.92 1.29

P2O5(%) 0.21 0.34 0.37 1.1 1.0 0.87 0.133

TheprimaryacidiccomponentsofflyashareSiO2,Al2O3andTiO2whilethebasiccomponentsare

Fe2O3,CaO,MgO,Na2OandK2O.AccordingtotheABBCombustionFossilPowerbook,thesum

oftheacidiccomponentsrangesbetween20and90%whilethesumofthebasiccomponents

rangesbetween5and80%.Theratioofthesumofthebasiccomponentsoverthesumofthe

acidiccomponentsrepresentstheBase/Acid(B/A)ratiooftheash.

B/A=[Fe2O3+CaO+MgO+Na2O+K2O]/[SiO2+Al2O3+TiO2](10)

ThefollowingtableillustratestheB/Aratiooftheashfortheapplicationsofinterestasa

functionoflimeandSO3contentintheashaswellasthevolatileSinthefuel.AshwithhighB/A

ratiotendstohavehighCaOconcentrationwhichwillreactwiththevolatileSandformCaSO4.

TheSO3contentintheflyashactuallyrepresentstheamountofScapturedintheformofCaSO4.

ThisreactionneutralizestheScontentofthefuelandminimizesthepotentialoftheammoniato

beadsorbedontheash.Thehypothesis,therefore,isthatthehighertheB/Aratioaswellasthe

CaOandSO3contentoftheash,thehigherthealkalinityoftheash,andthelowerthepotential

forammoniaadsorptionontheash.TheB/Aratioiscalculatedforeachapplicationusingthe

informationonTableIValongwithequation(10).TheammoniaadsorptionontheashistakenfromTableIIandtherelationshipofalltheseparametersissummarizedinthetablebelow:

TABLEV:RelationshipbetweentheammoniaadsorptiononashandtheScontentofthefuel,

aswellastheB/Aratio,SO3andCaOcontentoftheash

Baldwin Cardinal Lone

Mountain

Miller Pleasant

Prairie

Sioux

Stanton

NH3adsorbed(%) 86 84 100 14 15 76 100

B/A 0.42 0.586 0.175 0.964 0.729 0.653 0.084

Sdaf(%) 4.29 3.864 0.92 0.463 0.35 0.97 1.079

SO3(%) 4.70 4.183 1.5 16 24.7 10.922 1.292

CaO(%) 5.40 4.542 2.56 26.6 12.2 21.32 1.157

Ash(%),dry 10.77 9.4 7.5 5.85 7.3 5.3 6.9


7/16


Thisinformationisillustratedgraphicallyinthefollowingfourplots.

0.000

0.200

0.400

0.600

0.800

1.000

1.200

0.000

5.000

10.000

15.000

20.000

25.000

30.000

0 20 40 60 80 100

Base/Acidrao

CaO

(%)

Adsorponrateofammoniaonash(%)

Figure1:AmmoniaadsorbedontheashasafunconofashCaOandBase/AcidRao

AshCaOcontent Base/Acidrao

0.000

0.200

0.400

0.600

0.800

1.000

1.200

0.000

5.000

10.000

15.000

20.000

25.000

30.000

0 20 40 60 80 100

Base/Acidrao

CaO

(%)


Figure2:Ammoniaadsorbedontheashasa

funconofashCaOandBase/AcidRao

(ExcludesSioux)

AshCaOcontent Base/Acidrao


8/16


0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

4.000

4.500

0.000

2.000

4.000

6.000

8.000

10.000

12.000

14.000

16.000

18.000

0 20 40 60 80 100

Sulfurcontent,daf(%)

SO3(%)



funconofashSO3andfuelScontent

AshSO3content Sulfurcontent(%)

0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

4.000

4.500

0.000

2.000

4.000

6.000

8.000

10.000

12.000

14.000

16.000

18.000

0 20 40 60 80 100

Sulfurcontent,daf(%)

SO3(%)



funconofashSO3andfuelScontent(Excludes

Sioux)

AshSO3content Sulfurcontent(%)


9/16


Reviewingtheaboveplots,itappearsthatinthecaseoftheSiouxStation,whichusedthe

blendedPRBandbituminouscoal,thepropertiesofthebituminouscoaloverwhelminglyaffect

theadsorptionpotentialoftheashalthoughtheaverageBase/Acidratioishigh,andtheCaOand

SO3concentrationsarerelativelyhighaswell.Theblendedcoalapplicationintroducesasmall

amountofscatterinthedata,andconsequently,Figures2and4shouldbetheonesusedin

estimatingtheadsorptionpotentialofanygivencoal.

Thesegraphsshowthattherateofammoniaadsorptionontheashisverylow,lessthan20%,

whentheB/AratioaswellastheCaOandSO3concentrationsarehigh.Ontheotherextreme,as

theB/Aratiodropsbelow0.15,theammoniaadsorptionontheashapproachesalmost100%.In

general,theammoniaadsorptiongoesupiftheScontentisover1%,however,theScontentby

itselfisnotthebestindicatorofhowhightheammoniaadsorptionratewillbeandwillneedto

beusedinconjunctionwiththeCaOandSO3concentrations.

EnteringtheinformationreadfromtheplotsintoEquation(9),theamountofammonia

adsorbedontheashmaybeestimated.Thisisanexpectedvalue,however,andisnotintended

formakingguarantees.

Workingexamples

Themethodologyforassessingtheamountofammoniaadsorbedonflyashisoutlinedbelow.

Theanalysisisdoneforthreedifferentcoals,namely:Arclair,AntelopeandSanMiguelLignite.It

isassumedthattheamountofflyashis80%ofthetotalashandthattheamountofammonia

slipmeasuredattheeconomizeroutletis3ppm.ForthelowSapplications,itwillbeassumed

that30%oftheammoniaslipwillbeavailableforadsorptionwhiletherestwillgooutthestack.

ForthehighSapplications,itwillbeassumedthat70%oftheammoniaslipwillbeavailablefor

adsorptionwiththerestbeentiedupintheairheater.

Appendix1showsthatArclairhasaB/Aratioof0.42,anSO3contentof1%andaCaOcontentof

4.2%.Appendix2showsthattheScontentofthisfuelis3.46%onadry,ashfreebasisandtheFd

factoris9623dscf/MMBtu.Inaddition,theashcontentis8.65%andtheHigherHeating

Value13149Btu/lbonadrybasis.Figure2illustratesthatforacoalwithaB/Aratioof0.42,the

adsorptionrateisabout70%whilebasedonaCaOcontentof4.2%,theammoniaadsorption

potentialapproaches100%.ThishighadsorptionrateisfurthersupportedbytheSO3andS

concentrationonFigure4.Consequently,byaveragingoutallthesefactors,theammoniaadsorptionontheashforthisparticularcoalisabout90%.

ApplyingtheaboveadsorptionrateinEquation(9),andassumingthatonly70%oftheammonia

slipwillbeavailableforadsorption,orjust2.1ppm,itisestimatedthattheammoniaadsorbed

ontheashinthisapplicationis196ppm-w.Thisiswellabovethe50to100ppm-wthresholdfor

ashsoldtothecementindustry.Fortheadsorbedammoniatostaybelowthisthreshold,the


10/16


NH3slipwillneedtobemaintainedbelow2ppmwhichwillseverelylimittheapplicabilityofthe

SNCRprocessandperhapschallengetheSCRprocessaswell.

Forcomparisonpurposes,theaboveanalysisisrepeatedforAntelopecoalunderthesame

conditions.TheB/AratiofromAppendix1is0.77,theCaOconcentrationis23.6%andtheSO3

concentrationis10.1%.ThefuelanalysisinAppendix2showsthattheScontentis0.35%ona

dry,ashfreebasisandanFdfactorof9852dscf/MMBtu.Theashcontentis7.21%andthe

HigherHeatingValue9505Btu/lbonadrybasis.UsingFigure2basedaCaOconcentrationof

23.6%andaB/Aratioof0.77,theamountofammoniaadsorbedontheashisexpectedtobe

around15%.ThisisalsoconsistentwiththeinformationinFigure4basedontheSconcentration

of0.35%whilebasedontheSO3concentrationtheadsorptionrateiscloserto30%.Byaveraging

outallthesefactors,theammoniaadsorptionrateforthiscoalisabout20%.Inaddition,since

thisisalowSPRBcoal,70%oftheammoniaslipisexpectedtobereleasedfromthestackandonly30%ofthe3ppmammoniaslipwillbeavailableforadsorption.Again,usingEquation(9)for

0.9ppmNH3slipavailableforadsorptionontheash,theamountofammoniaadsorbedonthe

ashisonlyabout15ppm-w.ThissuggeststhateveniftheSNCR/SCRprocessoperatesata

relaxedammoniaslipof5to10ppm,the50to100ppm-wthresholdofammoniaonashis

satisfied.

ThisisconsistentwithobservationsattheBoardmanStationinOregonwhereFuelTechranan

SNCRdemonstrationin2009.Manyflyashsampleswerecollectedandanalyzedandthe

averageamountofammoniaadsorbedontheashatthedifferentsectionsoftheESPwerebelow

11.7ppm-wevenwhentheammoniadosagewasashighas21ppm.Thisinformationis

summarizedinAppendix4.

Finally,theaboveexerciseisrepeatedforSanMiguelLignite.Appendix1showsthatSanMiguel

LignitehasaB/Aratioof0.112,anSO3concentrationof2.9%andaCaOcontentof3.0%.

Appendix2showsthattheScontentofthisfuelis3.66%onadry,ashfreebasisandtheFdfactor

is8665dscf/MMBtu.Inaddition,theashcontentis36.3%andtheHigherHeatingValueis8446

Btu/lbonadrybasis.UsingFigure2,itisdeterminedthatbothonthebasisoftheCaOandthe

B/A,theammoniaadsorptionpotentialapproaches100%.Thishighadsorptionrateisfurther

supportedbytheSO3anSconcentrationsonFigure4.

AsinthecaseoftheArclaircoal,sincethisisalsoahighScoal,itisassumedthat70%ofthe3ppmammoniaslipisavailableforadsorptionor2.1ppm.Surprisingly,whentheabove

adsorptionrateisusedinEquation(9),itisestimatedthattheammoniaadsorbedontheashin

thisapplicationisonly27ppm-w.Thisisaverylowconcentrationanditisduetothehighash

contentofthefuelwhichdilutestheammoniaadsorptioneffect.Clearly,incaseslikethis,the

amountofammoniaontheashisnotthedrivingfactorforlimitingtheammoniaslipbutrather

thehighpotentialforammoniumbisulfatefoulingontheairheatersurfaces.


11/16


Theaboveanalysishasnottakenintoaccounttheammoniaadsorbedduetounburnedcarbon.Based

onstudiesperformedbyFuelTechsSCRgroupatNipsco,itwasdeterminedthatammoniaalsoadsorbs

onunburnedcarbonandtheammoniaslipmeasurementisnotatruemeasureoftheammoniaslip

generatedinthegaseousphase.Thetrueammoniaslipwillneedtobeadjustedbythe%unburned

carbonassuminga10%adsorptionrate.Therefore,thehighertheamountofunburnedcarbon,the

higherthetrueammoniaslip,thehighertheamountofammoniaadsorbedontheash.

Conclusions

1. ForhighSbituminouscoals,about70%ofthegeneratedammoniaslipisavailableforadsorptionontheash.Approximately30%mayreactwithSO3toformammoniumbisulfateandsulfatesalts

whichmaydepositoncoolermetalsurfaces,andaverysmallportionisreleasedfromthestack.

2. ForPRBcoal,duetothelowSO3concentrationinthefluegas,asmallportionoftheammoniaslipwillparticipateintheformationofammoniumbisulfateandsulfatesalts.Inaddition,duetothehighalkalinityoftheash,thepotentialforammoniaadsorptionontheashislow,anditis

expectedthatthemajorityoftheammoniaslipwillbereleasedfromthestack.Forthepurposes

ofthisanalysis,ithasbeenassumedthat30%ofthegeneratedammoniawillbeavailablefor

adsorption.

3. Thepotentialofammoniaadsorptionontheashisgreatwhenthealkalinityoftheashislowasinthecaseofbituminousfuels.Undertheseconditions80to100%ofthegaseousammonia

availableforadsorptionontheashmaybeadsorbedontheash.

4. ThepotentialofammoniaontheashislowwhenthealkalinityoftheashishighasinthecaseofPRBfuels.Undertheseconditions,only10to20%ofthegaseousammoniaavailablefor

adsorptionontheashmayadsorbedontheash.

5. TheB/Aratio,CaOandSO3concentrationoftheash,aswellasthe%Scontentofthefuelaregoodindicatorsinassessingtheadsorptionrateofammoniaontheash.

6. TheashgeneratedbyahighSfuelmaybeveryacidiciftheCaOconcentrationislowandhasthepotentialtoadsorb100%oftheavailableammonia.However,theactualconcentrationonthe

ashmaystillbeanacceptablevalueforthecementindustry,ifthisfuelhasaveryhighash

concentration.

7. TheashproducedbythecombustionofaPRBfuelhasaverylowpotentialforadsorbingammonia.Thispotential,however,increasesinthepresenceofunburnedcarbon.

References

1. CombustionFossilPower,Windsor,Connecticut:CombustionEngineering,Inc.,1991

2. AirheaterFoulingbyAmmoniaBisulfateDeposition,FueltechInternalReport,March1996

3. LorimoreL.,EffectsofAmmoniaFromPostCombustionNOxcontrolonAshHandlingandUse.,FuelChemistryDivisionReprints,2002


12/16


4. DiscussionswithVolkerRummenhohlinternaltoFuelTech

5. HomepageofW.S.HintonandAssociates,FlyAshBehavior,www.wshinton.com

6. HandlingofAmmoniaintheAsh,FuelTechInternalReport,August1993

7. ImpactsofAmmoniaContaminationofFlyAshonDisposalandUse.EPRIReport1004609,October2001

8. InvestigationofAmmoniaAdsorptiononFlyAsh.EPRIInterimReport112172,December1998

9. ArchCoal,Inc.FuelAnalyses

10.AshChemistry,UltimateAnalysesandHeatingValuesofVariousCoals,www.et.byu.edu

11.AlstomCleanCombustionTechnologies,Canada:Transcontinentalprinting,2009


13/16


Appendix1

Fuel SiO2 Al2O3 Fe2O3 TiO2 CaO MgO Na2O K2O SO3 P2O5 B/A

BeulahLignite 21.23 13.97 12.25 0.42 16.36 4.46 6.50 0.22 24.60 0.00 1.12

Arclair 48.08 18.59 20.60 0.99 4.22 0.88 0.54 2.23 0.99 0.00 0.42

Buckskin 30.76 13.51 5.85 1.03 24.78 5.71 1.59 0.23 15.1 1.44 0.84

BlackThunder 30.67 16.46 5.10 1.29 21.32 4.80 1.43 0.35 17.67 0.92 0.68

Antelope 31.74 15.71 5.96 1.25 23.75 5.65 1.64 0.54 10.11 1.72 0.77

SUFCO 52.02 13.17 4.12 0.81 13.28 3.83 2.28 1.01 5.21 0.46 0.37

ElkCreek 53.94 23.57 6.58 0.99 3.94 1.41 1.76 1.59 1.76 1.01 0.20

McElroy 48.17 21.91 21.57 0.91 2.8 0.76 0.50 1.84 2.35

0.39

EasternKentucky 58.20 30.67 4.88 2.08 1.16 0.42 0.17 0.99 1.29 0.13 0.08WesternKentucky 51.06 18.41 19.56 0.99 3.04 1.14 0.63 2.88 2.02 0.12 0.39

Ohio#9 47.30 23.00 22.80 1.00 1.30 0.90 0.30 2.00 1.2

0.38

Bailey/EnlowFork 47.14 23.02 21.17 0.98 2.78 0.80 0.67 1.83 2.17

0.38

Illinois#6(2) 52.69 12.84 18.77 0.71 5.39 0.55 1.45 1.38 4.72 0.16 0.42

Kentucky#9 44.38 18.66 22.69 0.97 5.56 0.92 0.46 2.57 3.09 0.44 0.50

Pittsburgh#8(1) 41.70 20.66 29.33 0.90 2.08 0.79 0.40 1.74 2.35 0.15 0.54

Pittsburgh#8(2) 47.82 24.14 16.85 1.05 3.47 0.84 0.45 1.76 3.00 0.62 0.32

Pittsburgh#8(3) 39.66 19.68 27.79 0.85 4.54 0.85 0.90 1.21 4.18 0.34 0.59

Pocahontas#3 37.92 24.16 17.14 1.14 7.67 2.40 0.83 1.84 6.79 0.10 0.47

Alicia 47.48 24.08 17.11 1.12 3.57 0.68 0.68 1.58 2.99

0.33

SanMiguelLignite 66.79 19.69 1.69 0.88 3.04 0.49 2.63 1.91 2.86 0.01 0.11

UpperFreeport 51.53 24.35 13.46 0.92 2.48 1.30 0.30 3.07 2.43 0.14 0.27

Rochelle 34.10 17.00 5.50 1.30 23.5 5.50 1.70 0.40 9.80 1.20 0.70

CentralAppalachia 55.83 28.67 7.58 1.29 2.56 1.64 1.00 2.23 1.50 0.37 0.18

BelleAyr 27.80 13.10 5.50 1.30 26.60 7.00 1.30 0.30 16.00 1.10 0.96

Caballo 31.90 16.90 5.60 1.40 24.70 4.60 1.40 0.30 12.20 1.00 0.73

BlendCaballo&Illinois#6(2) 35.34 16.21 7.84 1.28 21.42 3.91 1.41 0.48 10.93 0.86 0.68


14/16


Appendix2

Fuel,dryashfreebasis

C

(%)

H

(%)

N

(%)

S

(%)

O

(%)

HHV,dry

(Btu/lb)

%

H2O

%ash,

dry

Fd

(dscf/MMBtu)

BeulahLignite 70.49 4.75 1.22 2.14 21.36 7210 34.8 9.5 10533

Arclair 79.91 5.34 1.79 3.46 9.50 13419 9.33 8.65 9623

Buckskin 76.26 5.15 1.00 0.51 17.08 8979 30.86 5.1 9856

BlackThunder 74.73 5.40 1.00 0.51 18.27 9479 26.03 7.59 9833

Antelope 75.93 5.29 1.15 0.35 18.23 9505 26.5 7.21 9852

SUFCO 79.70 5.28 1.41 0.45 13.15 12146 10.13 12.1 9812

ElkCreek 77.97 5.39 1.75 0.56 7.6 13651 6.71 10.7 9293

McElroy 80.30 5.49 1.66 3.76 8.76 14023 6.17 10.2 9447

EasternKentucky 84.00 5.50 1.70 1.00 7.80 14664 2.5 7.2 9691

WesternKentucky 79.00 5.60 1.70 3.60 10.10 13223 8.3 12.2 9632

Ohio#9 80.70 5.07 1.32 3.73 8.33 13009 10.33 10.4 9678

Bailey/EnlowFork 83.00 5.60 1.75 2.29 7.10 14038 6.32 8.06 9720

Illinois#6(2) 78.70 5.50 1.40 3.50 10.90 11773 18.3 7.59 9549

Kentucky#9 80.10 5.50 1.70 4.70 8.00 13700 6.1 11.9 9720

Pittsburgh#8(1) 80.90 5.70 1.50 2.50 10.90 13092 8.7 9.3 9843

Pittsburgh#8(2) 86.70 5.50 1.81 1.47 4.50 15012 2.6 9.34 9842

Pittsburgh#8(3) 84.07 5.58 1.53 3.86 4.96

10755

Pocahontas#3 91.65 4.46 1.31 0.79 1.62 14390 4.4 7.4 10387

Alicia 83.60 5.48 1.66 2.67 6.50 14237 5.96 8.6 9685

SanMiguelLignite 61.54 6.70 1.06 3.66 26.88 8446 32.49 36.3 8665

UpperFreeport 89.50 4.80 1.50 1.30 2.90 12372 1.1 8.58 12312

Rochelle 74.90 5.15 1.07 0.31 19.20 12566 2.73 6.3 9663

CentralAppalachia 87.84 5.43 1.58 0.92 4.23 14252 6.5 7.5 10035

BelleAyr 74.78 5.37 0.96 0.46 18.38 9148 29.8 6.55 9661

Caballo 74.94 5.27 1.07 0.38 18.34 8927 29.9 8.7 9876

BlendCaballo&Illinois#6(2) 75.58 5.31 1.15 0.91 17.08 9384

27.9

8.5 9814


15/16


Appendix3

Fuel B/A

S(%),

daf CaO(%) SO3(%)

Applicationsimilar

to

%NH3

adsorbed

BeulahLignite 1.12 2.14 16.4 24.6

Arclair 0.42 3.46 4.2 1.0

Buckskin 0.84 0.51 24.8 15.1

BlackThunder 0.68 0.51 21.3 17.7

Antelope 0.77 0.35 23.8 10.1

SUFCO 0.37 0.45 13.3 5.2

ElkCreek 0.20 0.56 3.9 1.8

McElroy 0.39 3.76 2.8 2.4

EasternKentucky 0.08 1.00 1.2 1.3 Stanton 100

WesternKentucky 0.39 3.60 3.0 2.0

Ohio#9 0.38 3.73 1.3 1.2

Kentucky#9) 0.38 2.29 2.8 2.2

Illinois#6(2) 0.42 3.50 5.4 4.7 Baldwin 86

Kentucky#9 0.50 4.70 5.6 3.1

Pittsburgh#8(1) 0.54 2.50 2.1 2.3

Pittsburgh#8(2) 0.32 1.47 3.5 3.0

Pittsburgh#8(3) 0.59 3.86 4.5 4.2 Cardinal 84

Pocahontas#3 0.47 0.79 7.7 6.8

Alicia 0.33 2.67 3.6 3.0

SanMiguelLignite 0.11 3.66 3.0 2.9

UpperFreeport 0.27 1.30 2.5 2.4

Rochelle 0.70 0.31 23.5 9.8

CentralAppalachia 0.18 0.92 2.6 1.5 LoneMountain 100

BelleAyr 0.96 0.46 26.6 16.0 Miller 14

Caballo 0.73 0.38 24.7 12.2 PleasantPrairie 15

BlendCaballoandIllinois#6(2) 0.68 0.91 21.4 10.9 Sioux 76


16/16


Appendix4

REPORTOFFLYASH

TitleoftheProject:BoardmanAmmoniaTestingDuringSNCRTrialsDateReceived:08-Dec-09

ContactPerson:PamFlynnTestedBy:KC

ProjectNumber:5257ReportDate:16-Dec-09

BoralSampleIDOperationsDetails SampleDescription NH3(ppmNH3inFA)

91208012 10PPMdoserate.Boilerundernormalconditions 12/4Row31A 3.7

9120801310PPMdoserate.Boilerundernormalconditions 12/4Row31C 5.6

9120801410PPMdoserate.Boilerundernormalconditions 12/4Row31D 9.5

9120801510PPMdoserate.Boilerundernormalconditions 12/4Row31E 10.8

9120801610PPMdoserate.Boilerundernormalconditions 12/4Row31F 13.7

9120801710PPMdoserate.Boilerundernormalconditions 12/4Row31G 15.5

9120801810PPMdoserate.Boilerundernormalconditions 12/4Row31H 11.7

9120801910PPMdoserate.Boilerundernormalconditions 12/4Row31J 3.8

9120802010PPMdoserate.Boilerundernormalconditions 12/4Row31K 3.5

9120802110PPMdoserate.Boilerundernormalconditions 12/4Row31L 3.2

9120802210PPMdoserate.Boilerundernormalconditions 12/4Row31M 3.0

9120802310PPMdoserate.Boilerundernormalconditions 12/4Row32A 7.29120802410PPMdoserate.Boilerundernormalconditions 12/4Row32B 2.8

9120802510PPMdoserate.Boilerundernormalconditions 12/4Row32C 8.5

9120802610PPMdoserate.Boilerundernormalconditions 12/4Row32D 6.3

9120802710PPMdoserate.Boilerundernormalconditions 12/4Row32E 17.3

9120802810PPMdoserate.Boilerundernormalconditions 12/4Row32F 13.5

9120802910PPMdoserate.Boilerundernormalconditions 12/4Row32G 11.7

9120803010PPMdoserate.Boilerundernormalconditions 12/4Row32H 21.2

9120803110PPMdoserate.Boilerundernormalconditions 12/4Row32J 13.8

9120803210PPMdoserate.Boilerundernormalconditions 12/4Row32K 6.7

9120803310PPMdoserate.Boilerundernormalconditions 12/4Row32L 4.6

9120803410PPMdoserate.Boilerundernormalconditions 12/4Row32M 2.9

9120803510PPMdoserate.Boilerundernormalconditions 12/4Row35COMPOSITE 7.7

9120803621PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row31A 3.0

91208037 21PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row31C 4.3

9120803821PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row31D 10.3

91208039 21PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row31E 22.6

9120804021PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row31F 21.9

91208041 21PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row31G 14.7

9120804221PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row31H 18.5

9120804321PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row31J 9.3

9120804421PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row31K 5.0

9120804521PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row31L 4.6

9120804621PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row31M 3.2

9120804721PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row32A 6.1

9120804821PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row32B 3.8

9120804921PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row32C 8.8

9120805021PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row32D 5.2

9120805121PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row32E 17.3

9120805221PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row32F 22.5

9120805321PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row32G 9.5

9120805421PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row32H 22.69120805521PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row32J 3.1

9120805621PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row32K 7.7

9120805721PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row32L 4.8

9120805821PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row32M 4.2

9120805921PPMdoserate.BoilersettomimiclowNOxconditions 12/6Row35COMPOSITE 11.7

45NELOOP410,SUITE700 SANANTONIO,TEXAS (210)349-4069

AmmoniaAdsorption.pdf

Documents

Transcript of AmmoniaAdsorption.pdf