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# OAR Box 1778 Prepped by Ollie Stewart



### Document

Number: 

# 234 ) 11-1-1

4

Docket Number: 

# A-90-0 6

Printed 10/28/2008 9:51:02 AM Sheet 234 of 276P. 2 MAYr\H O TH

U 16:1 3 FA X NO

. 

## C©SSSI^@KI©l^]C^/Jv]I^©^AWDM M

Fihfof: ^530- 1 D„ 9: Ma y 2 , 199 0

To: Donal d F

. Theile r - AM/ 3

From: Alle n J

. Hubbar d - AM/ 3

sub/ecu Bes t Availabl e Contro l Technolog y (BACT ) fo r WEPCO-Por

t Washingto n N0 X Emission s

Wisconsi nElectric'Powe r Company (WEPCO ) ha s submitte d a permi t applicatio nt o th e Departmen t pursuan t t o WEPCO' s planne d renovation s a t it s Por t Washingto n Powe r Plant . Thi s applicatio ni s th e culminatio no f nearl y two an d a hal f year s o f study

b y WEPC O an

d other s wit hrespec t t o ho w suc ha projec t ca n b e permitte d i n accordanc e wit hth e requirement s o f th e Clea nAi r Act . T o mak e a long stor y

short , WEPCO' s applicatio nassume s tha t onl y th e post-renovatio n nitroge noxide s (NO x ) emission s wil l b e subjec t t o th e PS D rules , an d therefor e t o continuou s applicatio no f bes t availabl e contro l technolog y (BACT) . WEPC O will , throug hth e us e o f enforceabl e permi t conditions , be abl e t o "ne t out 1 ' o f NSP S requirement s fo r particulate s an d S0 2 . I t i s importan t t o not e tha t WEPC O coul d ne t ou t o f PS D fo r NO ^ i f th e Por t Washingto nfacilit y

control s some moderat e amoun t o f NO . bevond curren t plan t practice , i n th e ver y

sam e wa y tha t WEPC O i s nettin g ou t o f NSP S fo r particulate s an

d SO. . Th e attache d analysi s o f th e BAC T portio no f th e applicatio nconsidere d informatio nfro

m thre e sources : 1 . Bechtel , actin g o n behal f o f th e applican t 2 . Vendor s (Exxo nan

d Hitachi ) o f N0 Xcontro l equipmen t 3 . Th e literatur e (N0 Xconferences , journa l articles , BACT/LAE R Clearinghouse , etc. ) Thi s analysi s conclude s tha t th e existin g combustio ntechnique s an d operatin g practice s employe d a t th e Por t Washingto nPowe r Plan t represen t th e bes t availabl e contro l technolog y (BACT ) fo r th e NO xemission s fro m thi s facility' s arch-fire d furnaces . Th e Departmen t furthe r determine s tha t th e appropriat e emissio nlimi t for;eac ho f th e boiler s a t th e Por t Washingto nPowe r Plant , consisten t wit hBACT , i s 0. 4 l bNO/MMBTU . Complianc e wit hthi s emissio n limi t shal l b e determine d o n th e basi s o f a Metho d 7 o f 4 0 CF R Par t 60 , Appendi xA

stac k tes t fo r a t leas t on e o f th e fou r boiler s t o b e permitte d (Unit s 1-4) .P. 3 MAY-1Q-S 0 TH

U9:0 7 FA XNO . 0000000000000000000 0 P . 0 2

Bes t Availabl e Contro l Technolog y (BACT ) fo r Emission s o f Nitroge nOxide s (NO x )

fro m Wisconsi nElectri c Powe r Company' s Por t Washingto nPowe r Plan t Ma v 2 . 199 0 Backgroun d Wisconsi nElectri c Powe r Company (WEPCO ) plan s t o renovat e th e existin g coal fire d arch-fire d boiler s a t it s Por t Washingto nPowe r Plant . Th e U.S . EPA an d th e court s hav e decide d tha t th e propose d projec t wil l b e subjec t t o th e NSP S an d PS D rule s fo r th e emission s o f nitroge noxide s (NO x ) followin g the renovation s a t th e plant . Thi s analysi s wil l focu s onth e PS D issu e o f applyin g th e bes t availabl e contro l technolog y (BACT ) t o th e renovate d plant' s N0 Xemissions .

Contro l Alternative s I norde r t o conside r th e possibl e NO xcontro l strategie s fo r a coal-fire d arch-fire d boiler , whic hi s th e onl y typ e o f boile r a t th e Por t Washingto n Powe r Plan t (PWPP) , th e Wisconsi nDepartmen t o f Natura l Resource s (the Department ) an

d WEPC O identifie d a numbe r o f technologie s whic hmigh t be successfull y

applie d t o contro l NO xemission s fro m PWPP' s boilers . Thos e technologie s are :

1 . Advance d Coa l Pulverizin g 2 . Combustio nModification s 3 . Selectiv e Catalyti c Reductio n(SCR ) 4 . Selectiv e Non-Catalyti c Reductio n(SNCR )

1 . Advance d Coa l Pulverizing
I nAugus t o f 1989 , th e Departmen t identifie d advance d coa l pulverizing a s a potentia l M L emissio nreductio ntechnolog y fo r applicatio nt o arch-fire d furnaces . WtPC O subsequentl y evaluate d a representativ e system , Mitsubishi' s MR S Pulverizer , whic hha s bee nsuccessfu l i nJapa nunde r certai ncondition s a t reducin g NO xemission s fro m coal-fire d powe r plants .P. 4 MAY**-10-9 0 TH

U9:0 9 FA XNO . 0000000000000000000 0 P . 0 3

A s earl y a s 1973 , Mitsubish i bega nt o develo p low-NO xburner s an d combustio n system s inrespons e t o new emissio nregulation s fro m th e Japanes e government . Th e MR S Pulverize r i s a new-generatio ncoa l pulverize r wit ha nintegra l rotary particl e siz e classifier . Wit ha significantl y enhance d abilit y

t o contro l bot hth e degre e and consistenc y o f fue l particl e fineness , roughl y a 10 % reductio ni nNO xemission s canb e achieve d relativ e t o conventiona l pulverizatio ntechniques . However , th e muc hlarge r potentia l fo r N0 xemissio n reductio ncome s fro

m th e abilit y

t o operat e a coal-fire d furnac e equippe d wit h th e MR S Pulverize r a t significantl y lowe r level s o f exces s air . Tha t is , th e us e o f th e MR S Pulverize r inconjunctio nwit h3 3 o r mor e percen t les s exces s ai r wil l resul t i na 40-50 % NO xreduction .

2 . Combustio nModification s Th e applicant' s BACT analysi s considere d severa l type s o f potentiall y applicabl e combustio nmodificatio ntechnique s fo r applicatio nt o th e PWP P arch-fire d furnaces . Thos e technique s are : lo w exces s ai r operation , low-NO x burners , stage d combustion , burner/furnac e wal l re-orientation , an d flu e ga s recirculatio n(FGR) . Th e analysi s states : Th e replacemen t burne r an d stage d combustio ntechnique s reduc e N0 X formatio nb

y maintainin g th e air/fue l rati o initiall y a t sub stoichiometri c levels , the nincreasin g th e proportio no f ai r a s th e combustio nproces s continues . Burner/furnac e orientatio n limit s NO xformatio nb

y minimizin g th e temperatur e o f th e combustio nproces s throug hradiatio nt o th e furnac e walls . Flu e ga s recirculatio nals o minimize s th e combustio ntemperature , throug hdilutio no f the fuel/ai r mixtur e inthe combustio nzon e wit hlo w oxyge nconten t exhaus t gas .

3 . Selectiv e Catalyti c Reductio n(SCR ) Th e investigatio no f selectiv e catalyti c reductio n(SCR ) a s a potentia l NO x emissio nreductio ntechnolog y fo r th e arch-fire d furnace s a t PWP P ha s spanne d virtuall y th e entir e two an

d a hal f year s o f th e developmen t o f BAC T fo r thi s project , Bot hth e applican t an d th e Departmen t hav e investe d considerabl e tim e an d effor t int o th e evaluatio no f SC Rapplicabilit y t o th e renovate d Por t Washingto nboilers . Thi s BAC T determinatio nreflect s th e state-of-the-ar t o f SCRwit hrespec t t o it s retrofi t applicatio nt o coal - fire d arch-fire d boilers , a s o f Ma y

2 , 1990 . SCR1 s a post-combustio nN0 Xcontro l technolog y involvin g th e injectio no f som e ammoni a (NH3 ) int o th e flu e gases , i nth e presenc e o f a catalys t (typicall y

vanadiu m pentoxide) . Unde r thes e conditions , a ga s phas e reductio n reactio noccur s wherei nth e ammoni a combine s wit hflu e ga s nitri c oxid e (NO) , nitroge ndioxid e (N0 2 ) , an d oxyge n(O2 ) t o yiel d molecula r nitroge nan d watar : 4NH 3 + 4NO + 0 2 4NH 3 + 2N0 2 + 0 2 > 4N 2 + 6H^ 0

> 3N 2 + 6H^ 0P. 5 

### MAY-1*0-9 0 TH

U9:1 1 FA XNO . 0000000000000000000 0 P . 0 4

SC Rcatalyst s generall y

perfor m bes t whe nthe y

se e flu e gase s havin g temperature s i nth e rang e o f 61 0 - 75 0 *-? , althoug hvendor s suc ha s Hitach i andMitsubish i hav e develope dspecialize dcatalyst s t o operat e effectivel y (unde r certai nconditions ) a t temperature s a s lo w a s 40 0 ° F o r a s hig ha s 80 0 °F. I naddition , Mitsubish i i s oresentl y developin g "high-temperature " catalysts , fo r us e wit h95 0 - 105 0 ° f flu e gases . Ammoni a i s supplie dt o th e flu e gase s upstrea m o f th e SC Rreacto r 1 na namou n roughl y stoichiometri c t o th e leve l o f NOw present . Th e reacto r i s designe d fjO v reductio nreaction s t o

Commo nSC Rdesig n J Xt.u.ii_ru i ttiiu a ma A i IIIUII I aiiniui i i a *>il p (i.e. , th e 

### unreacte dammoni a i nth e ga s stream ) o f 5 ppm . roughl y stoichiometri c t o th e leve l o f NO x

### present . Th e re ; t o hav e enoug hsurfac e are a t o allo w th e f)o

x

### reductio nrea d extensivel y

occu r and t o scaveng e mos t o f th e residua l NH* . criteri a ar e 8 0 - 90 % NO x

### contro l and a maximum ammoni a $Ti |

Tw o SC Rconfiguration s ar e applie di npractice : a "hot-side " arrangement , i n whic hth e reacto r i s inserte dupstrea m o f th e ai r heater s t o tak e advantag e o f th e 60 0 - 75 0 T flu e ga s temperature s generall y availabl e a t suc hlocations , an da "cold-side " arrangement , i nwhic hth e reacto r i s locate ddownstrea m o f th e ai r heate r an d (usually ) othe r emissio ncontro l device s t o tak e advantag e o f flu e ga s particulat e and/o r S0 2 

### clean-up .

NH 3 

# N Air

Heate r

Bciler SC

R ES P

Hot-Side , Hig hDus t SC R Stac k

Air Heate r 

## S j |J~ .

Soiler ES

P

Cold-Sid e SC R 

### GG H = gas-to-ga s hea t exchange r

4 , Selectiv e Non-Catalyti c Reductio n Earl y i nth e developmen t o f N0 X

### BAC T fo r Por t Washington' s boilers , WEPC O considere dth e applicatio no f selectiv e non-catalyti c reductio n(SNCR ) t o thi s plant' s arch-fire dfurnaces . I nMay , 1989 , Bechte l finalize da repor t t o WEPC O entitle d"Evaluatio no f Selectiv e Non-Catalyti c Reductio nTechnologie s fo r Wisconsi nElectri c Powe r Company. " Tha t repor t conclude dtha t "th e effectivenes s o f thes e (SNCR ) processe s ha s no t bee nestablished" , s o tha tP. 6 MA.Y-1-0-9 0 TK

U9:1 3 FA XNO . 0000000000000000000 0 P , 0 5

Bechte l believe dtha t SNC Rwa s no t ye t read y fo r successfu l commercia l applicatio nt o "pulverize d coal-fire d boiler s i nth e Unite d States. "
I nAugust , 1989 , th e Departmen t responde d t o WEPCO' s Ma y 198 9 submittal , w, . paragrap hessentiall y

agree dwit hWEPCO' s assessmen t o f SNC Rfeasibilit y fo r th e PWP P boilers :

Whil e th e selectiv e non-catalyti c reductio n(SNCR ) technique s evaluate d inyou r BAC T analysis , urea injectio nan

dammoni a injection , ar e promisin g technologie s fo r NO « control , w e agre e wit hyou r conclusio ntha t SNC Ri s no t ye t ready fo r commercia l applicatio nt o pulverize d coal , arch-fire d utilit y boiler s suc ha s th e unit s at Por t Washington . I t appear s tha t th e existin g firin g configuration s mak e applicatio no f SNC Rproblemati c fo r thes e particula r sources , i f fo r n o othe r reaso ntha nexcessiv e retrofi t costs . InApril , 199 0 th e Departmen t receive d new informatio nfro

m Exxo nregardin g th e feasibilit y

o f Exxon' s Therma l DeNO X(ammoni a injection ) proces s fo r controllin g N0 Xemission s fro m Por t Washington' s arch-fire d furnaces . A s a resul t o f thi s new

information , th e Departmen t wil l no w re-conside r SNC Ri n th e developmen t o f BAC T fo r WEPCO' s plan t renovatio nprojec t a t Por t Washington . Ther e ar e tw

o principa l type s o f SNC Ravailabl e toda y t o contro l NO x emissions : ammoni a injectio n(Therma l DeNOX ) an d ure a injectio n(NQJDut) , I n bot hcases , a reagen t i s injecte d int o th e flu e ga s stream an d react s wit h availabl e NO xt o for

m molecula r nitroge nan

d wate r vapor . I naddition , ure a injectio nproduce s carbo ndioxide :

NO + NH 3 + 1/4 J ---- > N 2 + 3/2^ 0 (DeNOX ) 2N O + C0(NH 2 ) 2 + 1/2-

g ---- > 2N 2 + C0 2 + 2H £ (NO^ut )
A carrie r gas , typicall y steam o r air , introduce s th e ammoni a o r ure a int o th e flu e ga s stream . Th e desig nan dplacemen t o f th e injectio nnozzl e i s a crucia l elemen t i nth e system , sinc e th e proces s depend s onth e injectio n momentu m fo r complet e mixin g o f reagen t an d NO x . Insituation s wher e flu e ga s temperature s var y

substantiall y

wit hdail y

level s o f operation , multipl e injectio nlocation s ar e use dt o ensur e tha t th e reagen t 1 s alway s injecte d int o flu e gase s wit hth e righ t temperatures . Commo ndesig ncriteri a fo r SNC R ar e 5 0 - 70 % N0 Xcontro l an da 5 pp m ammoni a slip .P. 7

-10-9 0 TH U9:1 5 FA XNO . 0000000000000000000 0 P . 0 6

Technica l Feasibilit y

o f Contro l Alternative s fo r Por t Washington' s Boiler s Th e Departmen t believe s tha t neithe r advance d coa l pulverizin g no r combustio n modificatio ni s technicall y feasibl e fo r applicatio nt o arch-fire d furnaces , sucha s thos e a t WEPCO' s Por t Washingto nPowe r Plant . An d whil e ther e ha s ye t t o be a singl e commercia l demonstratio no f eithe r th e SC Ro r SNC Rtechnolog y o na coal-fire d boile r inth e Unite d States , th e Departmen t believe s tha t bot h o f thes e technologie s wil l soo nbe successfull y applie d t o contro l N0 X emission s fro

m existin g pulverize d coa l boiler s i nth e U.S . I nfact , SC Ris , a s o f Ma y 2 , 1990 , technicall y

feasibl e fo r applicatio nt o WEPCO' s Por t Washingto nPowe r Plant . Onth e othe r hand , SNC Rdoe s no t ye t appea r t o b e feasibl e fo r WEPCO' s potentia l application .

1 . Advance dCoa l Pulverizin g Th e Departmen t concur s wit hBechtel' s assertio ntha t advance d coa l pulverizin g b v itsel f i s technicall y

infeasibl e fo r Por t Washington' s arch-fire d furnaces . Althoug hthi s technolog y ca nreduc e N0 Xemission s b y abou t 10 % b

y itself , i t i s reall y intende dt o b e use d a s a techniqu e t o allow a boile r t o operat e a t reduce d exces s ai r levels , usuall y i nconjunctio nwit hne w

generatio nlow-N0 x burne r technology . Bechtel' s analysi s o f th e applicabilit y o f MR S Pulverizer s t o Por t Washington' s arch-fire dfurnace s conclude s tha t "althoug hth e MR S pulverize r may provid e greate r contro l o f coa l finenes s tha nth e existin g pulverizers , th e us e o f th e MR S pulverize r wit hth e existin g boiler s wil l no t reduc e th e alraedy low N0 Xemission s a t Por t Washingto nPowe r Plant , bu t instea dwoul d likel y increas e NO xemissions. " Thi s conclusio ni s base donth e observatio n tha t th e coa l finenes s an dfuel/ai r distributio nrequire d fo r arc hfirin g differ s fro

m th e low-NO xburne r - overfir e ai r configuratio nfo r whic hth e MR S Pulverize r wa s develope dan dapparentl y

requires . Arc hfirin g i s characterize db y a long , delaye d combustio nflam e whic h represent s a kindo f stage dcombustion . Bechte l note s tha t "appropriat e hea t transmissio ninth e furnac e require s th e marriag e o f a boile r wit ha burne r an d flame patter nwhic hdistribute s th e hea t necessar y t o produc e desire d stea m condition s withou t producin g loca l overheating . Fo r th e Por t Washingto n boilers , th e long , delaye dcombustio nflame i s th e appropriat e matc hfo r th e furnace. "
WEPCO' s lon g operatin g experienc e wit harc hfirin g ha s resulte di nwell define d inge s fo r suc hinterrelate doperatin g variable s a s coa l fineness , exces s _,r , an

dindividua l burne r firin g rate s t o maintai nth e prope r flame shap e an dhea t distributio ni nth e furnace . A s a result , Bechte l believe s tha t "operatin g change s t o furthe r reduc e N0 Xformation , suc ha s a significan t reductio ninexces s ai r o r coa l fineness , wil l alte r th e flam e shap e and/o r intensity . A

shorte r mor e intens e flam e wil l adversel y

effec t hea t absorptio n an dstea m '•.-T-peratur

e control , an

dwoul d likel y

increas e N0 Xemissions. " Th e Departmen t find s thes e argument s t o b e persuasive . W e agre e tha t th e MR S Pulverize r technolog y

appear s t o be incompatibl e wit hPor t Washington' s arch -P. 8 HAY-10-9 0 TH

U9:1 8 FA XNO . 0000000000000000000 0 P . 0 7

fire d furnaces . Consequently , th e Departmen t conclude s tha t suc hpulverizer s ar e technologicall y

infeasibl e fo r controllin g NO xemission s from th e existin g Por t Washingto nPowe r Plant .

2 . Combustio nModification s Al l o f th e combustio nmodificatio nstrategie s reasonabl y applicabl e t o arch fire dboilers , tha t 1 s low exces s ai r operation , low-NO xburners , stage d combustion , burner/furnac e wal l re-orientation , an d flu e ga s recirculatio n (FGR) , ar e already

(a t leas t t o some extent ) inherentl y employe d a t Por t Washingto ni nth e desig nan dconfiguratio no f it s arch-fire d furnaces . Furthermore , thes e combustio nmodificatio ntechnique s applie dt o conventiona l boiler s rarely , i f a t all , resul t inlowe r NO xemission s tha nth e typica l N0 X emissio nrat e o f 0. 4 lb/MMBT Uexperience d b y th e Por t Washingto nboilers . Therefore , th e kind s o f combustio nmodificatio nstrategie s tha t woul d significantl y

reduc e N0 Xemission s fro m mos t conventiona l boile r type s simpl y woul dno t b e effectiv e whe napplie dt o arch-fire d furnace s suc ha s thos e a t Por t Washington . Th e delaye dcombustio nflam e whic hcharacterize s arc hfirin g i s a for m o f stage dcombustion . Th e existin g burners , thei r arrangement , and exces s ai r requirement s ar e al l matche dt o th e existin g furnac e t o produc e th e bes t combustio npatter nfo r th e furnace . I naddition , th e primar y combustio nai r i s delivere dt o th e furnac e a t a relativel y lo w (fo r pulverize d coa l firing ) temperatur e (les s tha n60 0 °F ) becaus e th e plant' s uniqu e coa l feedin g system doe s no t requir e ho t ai r fo r coa l drying . Th e effec t o f thi s "low temperature " combustio nai r o nth e furnac e combustio ni s ver y muc hth e same a s th e effec t o f FGR , whic hals o minimize s th e combustio ntemperatur e (through dilutio no f th e fuel/ai r mixtur e i nth e combustio nzon e wit hlow-oxyge n conten t flu e gas) . Th e Departmen t conclude s tha t combustio nmodification s t o Por t Washington' s arch-fire dboiler s woul dprov e t o b e ineffectiv e a t reducin g th e N0 Xemission s below curren t levels . I

ntha t sense , suc hmodification s appea r t o b e technicall y

infeasibl e fo r th e renovatio nproject .

3 . Selectiv e Catalyti c Reductio n(SCR ) WEPCO' s BAC T analysi s argue s ver y strongl y tha t SC Rtechnolog y

i s no t ye t technicall y

feasibl e fo r applicatio nt o pulverize d coa l boiler s i nth e Unite d States . Unresolve dconcern s abou t flu e ga s unburne d carbo nconten t (WEPC O refer s t o thi s phenomeno na s los s o f ignition , o r LOI) , chemica l propertie s o f U.S . coa l combustio nproduc t gases , ai r heate r pluggage , and catalys t disposa l (among othe r things ) appea r t o mak e th e successfu l applicatio no f SC Ra t Por t Washingto nproblematic . O nth e othe r hand , SCRvendor s (Hitachi , fo r example ) believ e tha t th e technolog y i s read y fo r commercia l applicatio ni nth e U.S . Fo r Por t Washingto ninparticular , th e highcarbo ncarryove r i nth e flu e gase s present s a

nadditiona l roadbloc k fo r successfu l SC Rapplication . I nth e absenc e o f carefu l planning , th e ho t surface s o f th e SC Rcoul d ignit e th e carbo ni nth e flu e gas . A resultin g fir e woul d b e clearl y undesirable , bu t Por ^ Washingto nexperience s fire s fro m time t o tim

e i n"downstrea m

equipment" ,P. 9 MAY*-1.0-9 0 TH

U9:2 1 FA XNO . 0000000000000000000 0 P . 0 8

includin g ai r heater s an dprecipitators . Th e Departmen t i s unconvince dtha t th e likelihoo d o f a fir e ina nSC Ri s an

y greate r tha ni t i s i na nai r heate r o r ESP , sinc e al l o f thes e device s contai nho t surface s an d high-carbo nflu e ga s streams . Por t Washingto nha s an d wil l continu e t o contro l particulat e emissions , wit ho r withou t a noccasiona l contro l devic e fire . Analogously , th e Departmen t wil l no t rul e ou t th e applicatio no f SC Rtechnolog y t o Por t Washingto no nth e basi s o f fir e potentia l alone . Amon g othe r mitigatin g techniques , th e SC Rinle t temperatur e coul d b e limite d t o some temperatur e "safely " below

th e ignitio ntemperatur e o f fixe d carbo ni na coa l combustio n product s ga s stream . Becaus e ther e ha s ye t t o b e a singl e commercia l demonstratio no f th e SC R technolog y

o na coal-fire d boile r inth e Unite d States , th e Departmen t recognize s th e hesitatio no f th e applican t t o simpl y transfe r th e successe s o f SC RinJapa nan

dGerman y t o PWPP . I t i s tru e tha t th e coal s burne di nJapan , Germany , an

dth e U.S . ca ndiffe r significantly , especiall y wit hrespec t t o th e content s o f certaintrac e element s an d sulfur . Suc hfue l difference s resul t indifferen t flu e ga s characteristics , whic hma y lea d t o th e prematur e foulin g o r corrosio no f downstrea m equipment , SC Rplugging , o r othe r operationa l difficulties . However , th e Departmen t believe s tha t i nth e ver y nea r futur e SC Radvocate s wil l b e abl e t o sho w tha t U.S . coal s an

d boilers , includin g thos e a t th e Por t Washingto nPowe r Plant , ar e i nfac t compatibl e wit hSC R technology . A t th e same time , th e Departmen t i s unconvince d b y th e Bechte l SC Rassessmen t tha t th e successfu l demonstration s o f SC Ri nJapa nan d German y ar e no t sufficientl y

transferabl e t o PWP P t o allow thi s technolog y

t o represen t BACT . Th e lac k o f dat a fro

m th e applicatio no f th e SC Rtechnolog y t o U.S . coa l firin g als o mean s tha t thi s technolog y ha s no t bee ndempnstrate d t o b e infeasibl e fo r Por t Washington' s boilers . Clearly , SC Rha s bee nsuccessfu l in a wid e variet y

o f coa l firin g situation s i nJapa nan d Germany , an

d tha t i s encouragin g fo r th e potentia l applicatio no f th e technolog y t o coal-fire d boiler s inth e U.S . I

nothe r words , th e Departmen t believes , a s o f Ma y 2 , 1990 , tha t SC Ri s technicall y feasibl e fo r controllin g N0 Xemission s fro m th e arch-fire dfurnace s a t WEPCO' s Por t Washingto nPowe r Plant .

4 . Selectiv e Non-Catalyti c Reductio n(SNCR )
A s i s th e cas e wit hSCR , th e potentia l applicatio no f selectiv e non-catalyti c reductio n(SNCR ) t o th e arch-fire d furnace s a t PWP P i s no t straightforward . Earl y inth e developmen t o f BAC T fo r PWPP' s NO xemissions , WEPC O note d tha t th e bes t flu e ga s temperature s fo r SNC Rcontro l mos t ofte noccu r somewher e in th e convectiv e passe s o f th e PWP P boilers . Thi s statemen t ha s two importan t implication s fo r th e liklihoo d o f successfu l SNC Rapplicatio na t PWPP : th e reagen t woul dhav e t o b e injecte d withi no r clos e t o superheate r tub e bank s an dpossibl y

a t severa l differen t location s fro m time t o time t o respon dt o boile r loa dshifts . I t 1 s Exxon' s April , 199 0 assertio nt o th e Departmen t tha t thes e latte r concern s hav e bee nsuccessfull y addresse dtha t forme dth e basi s fo r th e Department' s re-consideratio no f SNC Ra s a potentia l BAC T candidat e fo r PWPP' s arch-fire d boilers .P.1 0 HAy-rlD-9 0 TH

U9:2 4 FA XNO . 0000000000000000000 0 P . 0 9

Othe r potentia l problem s associate d wit hSNC Rinclud e high(mor e tha n20-3 0 ppm ) ammoni a sli pandai r heate r pluggin g fro m ammoniu m sulfat e o r bisulfat e deposition . Sinc e ther e ha s no t ye t bee na commercia l demonstratio no f th e SNC Rtechnolog y

applie dt o a pulverize d coal-fire d boile r i nth e U.S. , th e jur y i s stil l ou t onwhethe r SNC Rwoul d b e successfu l a t controllin g N0 X emission s fro

m th e arch-fire dboiler s a t PWPP . O nth e othe r hand , Exxo nindicate s tha t it s Therma l DeNO Xtechnolog y ha s demonstrate dth e abilit y t o contro l 50-60 % o f th e NO xemitte d fro m a Germa n we t botto m boile r firin g a 1.5 % sulfu r coa l an d ha s show

nsimila r succes s i n Japa ncontrollin g N0 Xfrom th e combustio no f a 3-4 % sulfu r petroleu m coke . Accordin g t o Exxon , th e 50 % NO xreductio nobserve d a t thes e unit s wa s achieve d withou t downstrea m

ammoniu m sulfat e o r ammoniu

m bisulfat e depositio n problems . Exxo nha s foundtha t tw o technique s appea r t o preven t thi s deposition : designin g fo r les s tha n5 pp m NH 3 sli p (t o preven t bisulfat e formation) , o r providin g exces s ammoni a a t injectio n(3: 1 NH3:S0 3 mol e ratio ) t o preferentiall y

for m ammoniu m sulfate , whic hi s a dr y precipitat e an

d passe s throug hboile r syste m

component s "fairl y

easily " withou t th e depositio n problem s associate dwit hth e bisulfate . Whil e Exxon' s experience s mentione d inth e previou s paragrap har e encouraging , th e fac t remain s tha t neithe r Therma l DeNO Xno r NO^u t ha s bee ncommerciall y applie do r eve nteste do npulverize d coal-fire d boiler s i nth e U.S . I t i s certainl y tru e tha t th e ultimat e succes s o f thes e technologie s i s directl y relate d t o specifi c boile r system parameters , includin g boile r configuration , flu e ga s chemistry , uncontrolle d NO xconcentration , reagen t reactio ntime , an d flu e ga s temperature . Finally , a s o f Ma y 2 , 1990 , th e Departmen t doe s no t posses s an

y documentatio nt o demonstrat e th e successfu l applicatio no f SNC Rt o mor e tha non e o r two coal-fire d boiler s anywher e inth e world . W e understan dtha t Exxo ni s preparin g a repor t fo r u s whic hwil l argu e tha t Therma l DeNO Xca nb e successfull y applie d t o contro l 50 % o f th e NO xemission s fro m th e renovate dboiler s a t PWPP , an d perhap s tha t repor t wil l be persuasive . Bu t a t present , th e Departmen t conclude s tha t th e successfu l demonstration s o f SNC RinGermany ar e no t sufficientl y

transferabl e t o PWP P t o allow thi s technolog y

t o represen t BACT . I

nothe r words , th e Departmen t believes , a s o f Ma y

2 , 1990 , tha t SC Ri s technicall y infeasibl e fo r controllin g N0 Xemission s fro m th e arch-fire d furnace s a t WEPCO' s Por t Washingto nPowe r Plant .P.1 1

I.AYTIO-9 0 TH

U9:2 6 FA XNO . 0000000000000000000 0 P , 1 0

Economi c Feasiblit v

o f Contro l Alternative s fo r Por t Washington' s Boiler s Th e Departmen t find s tha t th e cost s associate d withth e onl y technicall y feasibl e contro l technolog y fo r controllin g th e NO xemission s fro m PWPP' s boilers , selectiv e catalyti c reduction , prohibi t thi s technolog y fro m representin g BACT . Whethe r WEPC O woul d instal l an d operat e a hot-sid e or . a cold-sid e SCR , th e economi c impac t i s th e same : roughl y $8,30 0 - $8,50 0 pe r tono f N0 Xcontrolled . Th e Departmen t believe s tha t thi s leve l o f contro l cos t i s wel l inexces s o f th e rang e o f cost s appropriat e fo r N0 X BACT . A t th e presen t time , th e Departmen t ha s n o reaso nt o alte r Bechtel' s economi c evaluatio no f th e applicatio no f SC Rt o a boile r a t th e Por t Washingto nPowe r Plant . Th e result s o f Bechtel' s investigation s ar e summarize d below .

Cold-Sid e SC R9 80 % N0 XRemova l

Installe d Cost s (pe r Unit , 198 9 dollars ) SC RSystem

(Bechte l estimate ) 17,674,52 5 WEPC O Cost s (engineerin g & overhead ) 1,704,71 9 SAR A Study 3,00 0 NH 3 & Ai r Heate r Enclosure s 90,60 0 Auxiliar y Powe r (flu e ga s reheating ) 400,00 0 Baghous e (contro l o f increase d P M fro m SCR ) 4,700,00 0 Wastewate r Treatmen t Expansio n(componen t wash ) 809,00 0 TOTA L INSTALLE D COS T $25,381,84 4

2 . Annua l Cos t (pe r Unit , 198 9 dollars , 60 % capacit y factor )
VARIABL E COST S Ammoni a 64,38 6 Electricit y

104,18 8 Catalys t Replacemen t 1,700,00 0 Catalys t Disposa l 25,00 0 Steam 7,25 0 Ba g Replacemen t 766,66 7 Hea t Rat e Penalt y

235,46 0 SUBTOTA L $2,902,95 1P.1 2 HAY-rO-9 0 TH

U9:2 8 * FA XNO , 0000000000000000000 0 P, 1 1

FIXE D COST S Labo r 620,32 1 Materia l 30,40 0 CEM Contracto r 15,00 0 Washdow n8,00 0 Wastewate r Treatmen t 800,00 0 SUBTOTAL $1,473,72 1

ANNUALIZE D INSTALLE D COS T (amortize d @ 5.5% , 1 8 years ) $2,256,95 1

TOTAL ANNUAL -COS T $6,633,62 3

3 . Annua l NO xReductio n(80 % x97 3 tons ) 77 9 ton s

4 . COS T PERTON

O F NO xCONTROLLE D $8516/to nP.1 3

•rO-3 0 TH U9:2 9 FA XNO , 0000000000000000000 0 P, 1 2

Hot-Sid e SCR0 80 % NO ^ Remova l

1 . Installe d Cost s (pe r Unit , 1S3 9 dollars ) SC RSystem

(Bechte l estimate ) 19,847,00 0 WEPC O Cost s (engineerin g & overhead ) 1,914,25 6 SAR A Study 3,00 0 NH 3 & Ai r Heate r Enclosure s 90,60 0 Economize r Additio n(t o contro l SC Rinle t Temp. ) 945,00 0 Baghous e (contro l o f increase d P M fro m SCR ) 4,700,00 0
TOTA L INSTALLE D COS T $27,499,85 6

2 . Annua l Cos t (pe r Unit , 198 9 dollars , 60 % capacit y factor )
VARIABL E COST S Ammoni a 64,38 6 Electricit y

104,18 8 Catalys t Replacemen t 2,300,00 0 Catalys t Disposa l 45,00 0 Steam 7,25 0 Ba g Replacemen t 766,66 7 Hea t Rat e Penalt y

78,48 7 SUBTOTAL $3,365,97 8 FIXE D COST S Labo r 620,32 1 Materia l 30,40 0 CEM Contracto r 15,00 0 Washdown8,00 0
SUBTOTA L $673,72 1

ANNUALIZE D INSTALLE D COS T (amortize d $ 5.5% , 1 8 years ) $2,445,28 5

TOTA L ANNUA L COS T $6,484,25 4

3 . Annua l NO xReductio nx97 3 tons ) 77' . to- s

4 . COS T fr O F NO x.E D $8325/to n