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## Twenty

..Five Years of

# seR Evolution; Implications For US Application ADd Operation

J. 

### E. Cicb11JlOIDCZ**Consul~** 236 N. Santa Cruz Av.enue, Suite #202 Los Gatos, CA 95030



### I-J. MudD Fossil 

### Energy ReS@fCh 

### COJpOnltlon 

### 23342-C South Pointe Drive Lagtlna Hills, CA. 92653



### ABSTRACT

In the 25 yean since the 

### first commercial mstallatiQnS in 

### Japan. sea technology b.as evol"ett in 

### response to changing 

### applieatiou conditiOJlS. 

### For example, present..-day 

### catalysts fefl.ture 

### lhmner wallll, 

### improved mass tl<QlSfer 

### anil activity, and betterpoison resistance 

## mlm earlier gener4tion 

### pm4uots. Additionally, catalyst

### IWluagemenJ slrategie& frequently utilize cawyst& 

### from suppliers 

### and with**~eametty** 

### different from the original**sp:cificatio~** to 

### :improve opfmtion and minimize cost. Catalyst

### rc:geoer:alioll Jather tbau replacement 

### is playing 

### a. role. Reactor design and layout has evolved 

### to adopt where neccsBal)'. 

### static mixers to promOte contacting ofteagem 

### and flue gas. These features 

### improve perfonnance and 

### offe.r lower cost, butmay increase the need for monitoring mld 

### diaguostic :measurementS.



### INTRODUCTION

By the 

### year 2004 7 in excess of 100 GW of**coal~fued** capacitY in the US 

### nmy be equipped WIth seR NO;.. control technology, to :mitigate: "seasonal" ozone prodncd-on as mandated by Title 1 of 

### the 

### 1990 Clean Air 

### Act Amendments 

### m. The 

### application 

### oiseR in 

### the US will have evolved from two prior generations of**d~s.ign:** the first commercial applications in 

### Japan. in 1:be: late 1970s, 

### and subsequent installations in 

### Europe (predomimlt.lIJ.y Gcnnany) in tbe**mid~** 

### 1980s. SCR precess design basis 

### and opeming requUernems 

### have significantly evolved 

### from. these prior 

### generations, both 

### simplifying and, 

### in 

### some: wa.yS, complicating tbe 

### pending operations in the U.s. This paper 

### reviews the key design and opeta:tional evolutions, and projects bow fumre US 

### operation may be affecfCd..


### BACKGROUND AND HISTORY

Strict**N~** emission 

### limits were implemented 

### Py lhe Japanese**~eral** govermnent as early as 1973. Local authorities mandated additioual reductious. lead by Yokohama CitY 

### in 1980 (2). Regar4ing**~w** 

### senemting

# umts, Japan's 

### Electric PowerPevelopmegt CQm.pauy 

### (EPDC) was requited to "'cap' the**N~** emissions fi'om the 

### two.-U!lit Takehata Station to 

### allow construction of

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### a 

### thil"d. coal-fired 

### lUlit. ThesereqWrement& 

### prompted early 

### R&D and pilot investigations to evaluate SCR.**NO~** contr:ol to achieve at least 50-6<FA!**N~** removal Figure 1 presents a timeline ofsignificant evenlS t"egarding the development and 

### comme:rciaJizatiOJl ofSCR. technology.
Figure 

### 1. Timeline OfKey SCR Events

1st Reuofu

## u.s. Coal Unil:Merrimaek



# t New Madrid.-

rl J Firat Gl:mlan \ll\U: lSf**N~** U.S. Coal**Ne~~** Uoit; Carneys Point .Akbacbl.PeiziSBIl Uuil5 (4:W MW)

I .fRGpasses**Go\'~l ~far**  I..mge Boiler**f;a$li1la~** 100 ppm Holdalido B11:Cttic;
TClmafO-A'lSUlna

- (114 x2S0 MW) Cbugdr,1J Elec1ric:

_ SbimoQl:Ski(17S MW.50%

I**I~** 

### I 

# 1995

# l~5ji9~O
2IJ..30 pilotplants on oil.**gus~** and retinety**~iIS** aPOC Takam Unit: 1; 250 MW Qexno (800/0, lowduSl) 

# . 1985

APienic

- "1!phltmc" Witn=ssedm Pilot Plants

# I~Or

1stU.S. Gas**Unil;LAP~** Haynes 

# 2000

1st Evidence ofAs PQisonmg in the US (OUCJStanwn Unit 2)

Subsequent to the approximalely 20·30 pilot plants oporated in Japan in the late 19705 (mostly

on fuel oil 

### and natutal gas). several demonstrations ofcoaH:ked. 

### units were**conduc~** Among the fi:rsJ SCR. demonsp;ations was 

### the 175 MW Shimonoseki STation ofChugoku Electric, treatmenf on 25% offlue 

### gas from 

### the Hokbido Eleelrlc Tomato-AtsUma**Station~** and. EPPe's 

### Takehara Station. where for the latter parallel reactors compared catalyst from two suppliers. Both the Tomato-Atsuma and Takelmta units 

### employed.l1.ot-side ESPs, providing a 

### low ash e.nviromneur to 

### the catalyst. NOx removal 

# u-om. tbese unitS ranged 

### from S()..80%. with a 5-10 ppm residual NU3 limit. ThUfi. early 

### coal-fWd experience 

### was 

### divided between high dust and low dust 

### applications. Sigpificant expcric:nce with high 

### dusr SCR. continued 

### with se"eral earlyapplicanolls in Germany in the mid-1980s, in response to the Oovernwent Ordinance For Lm-ge Boilers. adopted by 

### the

# men Fecleral RepUblic ofOenmmy l3}. Neckarwerke's AbbachlDeiszeiu Unit 5 was IePorteclly the tits! coalftfired commercial unit in 

### Germany on a dry-bottom boiler. and Knepper C the first 

### -slag·tap

.... boilt:.f 

### it-pplication. NO. 

### "!nOva! ped'Ql'DW).ce 

### in the 

### Gezman 

## ana El.P"Qpean applications increased to 

### generally 80%. with 

### Sl:kcredhigh NOx.-emitting Wlirs 

### such as 

### Knepper C achieving 90%. Experience in Gennan.yalso identified aTSenic poisoning ofcatalySIS through hom 

### pilot: plant and fUll-scale ex.perience, and:Wnher delnoDStrated thal control of residual N1!3 to 2-3 ppm**(~not** 5 ppm) was in 

### moat cases required TO maintain a5.b utiliZation. In the US. the Haynes Station oflbe 

### Lo¥ Angeles Depanmem afWater And Power was the fIrst: utility SCRapplication, employing in·duet design. fornatw"al gas 

### firing.. The first coal-fired applications for new plan:18 (Carney's Point) and fel!ofit (Merrilnaclc Unit 2) followed in the

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### early 1990s. Finally, 

### arsenic**~isoning** was 

### witnessed 

### in the 

### US at 

### the 

### Orlando Otilities Commission Slanton Uilit 2. f: •


### EARLY UNIT DESIGN CHARACTERISTICS

Table 1 StJromari2es the 

### key desip 

### variables for several early SeR 

### applications in Japan and Germany. NOli: 

### reduction varied 

### sjgnificamly. with removal efficiencies from 50% to approaching 90%, the 

### latter applied to high NO

... emitting units. The low sulfur level ofcoals 

### fued in 

### Japan minimized conCml 

### for 

### SOz conversion, at least for same units. 

### Also, limited 

### eJtperic:nce 

### with high dust 

### applica.lions had not identified the trUe impflCt 

### ofresidual**~;** 

### thus. cOl1'trolla 5 ppm (and 

### at

### limes 10 ppm) 

## was allowed for 

### coal-filed applications. Figure 

### 2 iUusnates the**c::a~%** geometry 

### elnployed al 

### Tomato-Isaku. and ODe 

### Takehara reacTOr. 

### which consisted of"pipes" 

### wUh walls of5 nun to 

### avoid erosion. Conversion OfS02 

### approached 2% for

some ofthese designs. which was 1lOtproblemalic for lbe early low sulfur content coals.

Table 1. 

### Early Commercial SCR 

### JnstaUations; Destgn Fetmu"es

EPPCI Shimonoscki Nc:ckarwl:rkcl Necbrwerke! 

### 'SVSI 'DESIGN**T~** (198J) Altbach (l98S) WaIheim Hcilbronn VAlUABLE (1980) (1986) 11985) 

### HSm1Pust/4)w Pust LO HD lID IID HD Inlet NO. (ppm) 300 500 300 7S0 325**NO~** Reduction1%) 80 50 66 88 80 Rel>idual oM'!. (pnm) 5 5 S 3 5 

### 902 Conv. (%) 1 1 ..;2 <2 <2 Space Velocit:Y 2300 3000 3340 1900 2850 (lJh) 

### Figure 2: Early Pipe--Sbaped Ca-mlyst Geometry

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### COMPARISON TO DESIGNS FOR US APPUCATION

T!u:re are numerous design featuroS ofSCR process equipment which Qistinguish the imminent US applications from predecessol'S. These include (iI.)**~yst teehnolo8Y~**  (b) process condirlOD.S applied. (e) reactor layout. (d) reagent injection eqQipmenlt (6) coal-fired experience base. (1) 

### rea-gem fype and handling systemS., awl (g) 

### balance-of-plant activities. Items {a} through (e) will he addressed in some 

### derail. with. highlights norcd for (t) 

### and. (g). Subsequent lO this t'!isCu:>51on. 

### data describing long-term operetion and 

### eval.uation ofa caWysl WElImgement strategy 

### employing regeneration is presented. 

### Catalyst

Possibly the most significant: 3Clvauc:cs have peen achieve4 

### in catalyst U:chnology. resulting in 

### increased performance and lowerproduction COSt. 

### hnprovements r.o both C$llyst 

### geometrY and composition were realized.

The limited strength ofextnlded material, or ille ability to bond catalytically active ingredients 

### anto a substrate, dicmtea.**~aJ.y$t** 

### geometry for cady**desi~.** 

### Accordlngly, relatively thick: 

### exmuled walls or coatmss were 

### necessary 

### to provide 

### erosion resisumce. Figure 2 depicted 

### me pipe-sJmpe geomeltY employee 

### in sevc:ral early 

### ftPplieations. requiring a 5 

### mm thick 

### wall 

### Jo prevent erosion. Table.2 compatts the geomeuical**cba.m~stics** ofscveral c:a:rly catalyst 

### products, showing how

# me decrease in 

### wall thickness improved a.vailable surface areafor cxl4Ud.ed**:ma~l. Mos~**  norablc: 

### ill Table 2 is lhe increase in surtace area-to-volume ratio, which for some specific products is significant**Of~tion** are the physical chatacrer.istics oEplate

### type caTalySIS. which 

### otft:r**~ng** 

### the highest 

### open area. {e.g

... 

### lowest flue gas pressure 

### drop} and have fcmuUDed relatively consRnt to exploit that impommt feamce. Also ofnote is the introduction ofceramic fibers as sullsttate. offering signifioavt surmcc area. ofreaction pe. unit weight.

Table 2. Evolution ofQltalyst Physical Properties: 1979

- 2001

PifA:fJ or**Cbaracferisrl~** Wall Surface Ph}'SiCllI**~iOP** Thickness ArealVolume Ope4Area Cbamcterlstic Unit GeometrY lixmn} (mm) mZ/m3 (%) lllllan 1919 various Dmc 30 5 -200 -60 JapllB 1980 Sbimonoseki ,;uid 9.8 1.8 333 67 JlmlUl19M**18~5** i Yokoouka 2rid 7.4 1.4 438 66**Euto13~** 1985 Alu.d1-Deizsbu. grid 7.2 1.4 448 64 EuroPe 1986 KneuDer md 7.4 I.I 460 73**Euroo~** 1989 Mchrwn I claft: 6 <:l 330 82 US.199S 

## oue I 'Plate 5.4 <:1 368 84 US.200() NCWtMadrid IfU'lcl 9.2 0.23 383 83 wtious IRnI1 7.4 0.83 480 79 US,2DOI

....arious eorruglJtc4 10.6 1 35)0 78 ! l nlatc: (hvddia)

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### For some 

# sca applicafions. the higher 

### specific sw:1ace 

### area.. smallerpitch 

### C1UalysIS 

### are :purposely notutiliZed., and instead 

### the 

### larger pilch, 

### lower specific**~.** area. 

### designs are used to 

### avoid ash 

### plugging and 

### deposition. In**f~t.** 

### a**"casoadinS~'** 

### cata1}'st pitch (pitch size decreases with 

### each catalYSt layer 

### in me diTecnon ofgas 

### flow) is**ft~uent1y** used 

### in :many 

### STations operating in EUtope to**~ge** ash dcp<mnon and pluggiu; • Although no SCR. retrofit units in tbe US at 

### ptesepr: using 

### me cascacI.iDg 

### approach wiTh 

### iuitial catalyst 

### inventory. some adjusnnent ofpitch

to 

### opemting characteristios**i~** 

### anticipated 

### with**ex:peri~e.** CtlmpositiDn
Catalyst 

### compoSition changes have increased activity 

### wmle maintaining or teducing convecsion OfS02 to 

### SOs. and provided resistance to arsenic poisoning. Specmcully, catalyst suppliers have 

### employed additives 

### as well 

### as improved 

### :manufactUring anel processing techniques that in:flucn.ce 

### the available surface 

### mea. for reaction. The**~mmon Ti~4based**  catalysts 

### also caD 

### employ molyPckl1Uln Uioxide**(M~)** and tungsten trioxide (W0s). in**~tion** to the key uctive 

### ingredient" vanadium. pe1lroJQde (V20S). 

### Perhaps 

### lh.e most significau.t 

### oonsequence ofthe improved l13a.Q

..**ufac~g** 

### process has been 

### the increased**''porQsi~'"** of

## me catalyst

- and 

### WI: abilitY lO 

### Qffer high 

### mass mmsfer a$"l 

### area. 

### torreacnon

- withom: compromise to tmJsion resistance.

The combination ofbigher S\llface area 

### per**~ohvne** 

### ofea.talySt 

### and catalytic activi'Cy, coupled with 

### ca.Ta!yst managementrecbniquea, has 

### probably rcQuced the

# wnw volume ofcaJalyst employed for 

### a given application.. 

### CoPlpmsons to 

### cady dc:sisns can. be misleading as both NOx removal targets and the 

### iuitial ea.tal:yst guata:!1tce 

### period have evol'Ved. However. Table 2 data when 

### compared to 

### present space velocilies for 90% NOlt 

### removal and 2 ppm residual 

### NH3 suggest lower voltmle 

### il> 

### currently applied. 

### Thia im.PIOvemcm leaves less margin for design or operating 

### Im"ors or aoomalies**com~ed** to the more**~a.live** European applica.tions. 

### Consequently, operatol'S will 

### benefit from detailed process monitoring to 

### diaguose and detect 

### performance n-c:ndS as early as possible.



### Process Conditions

The 

### selection ofSeR "process conditions"

- the distn"butiOll oftlue gas 

### veloci'tY. NHVNO ratio, and the range ofacceptable ternpermure that establish the operating environm.ent for the catalyst· 

### have evolved to 

### support present perfomnwcc: targetS. There are**sev~ml** 

### methods of specifying

## me distribution ofvelocity and NHYNO ratio; this 

### :paper will utilize the standard 

### deviation (SO) 

### ofd1e 

### measurements.
Figure 3 iUusrrares the role offlue gas 

### velocitY and 

### NH3INO ratio SD on**NO~** 

### renwval performance fUld :residual 

### NIh. These data 

### represent a perfum:Jance calculation fur 

### an inlet**NO~** 

### content of0.30 

### IbsIMBm. employing a 

### ea.talyst With 

### space velocity of3200 lib, and 

### grid-tY,pe caralyst of7.4 

### nun piTCh. 

### The process calculations employ 

### a nmdom distribution of

### initial velocity and**NH~~** 

### ratio across 

## me fiWface of

### a. catalyst. chatacterized by 

### varying levels of non-unifonnity. At each loc:atiQn on t.be catalyst. 

### the local. NO" teducricn and N1!3 

### slip were calculated and the results inrcped OVcl" the surface. Unifonn 

### velocUy enhances 

### ped"onnance by proVlding unifo:an residence time across th.e catalyst., insuring no "'cells" have inadequate

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Figllre 3: 

### Role ofMa1distribu1ions in 

### Velocity and NHJ!NO on 

## seaPenoI1W\I1ce

10

8


### e 0- 

### 6 Q..

= 

### 4 :r: 

### z 2

0 

### 80 8S 90 

### 95 100 dNOlc, % __ Vel..$td. Dev. 6%

_ Vol-$tei. Dev. 10%

--6- Vel-5ld Dev. 15%

-&-- VeI-St£L Dev. 22%

_ Vel-Std. De". 34%

(a) Velocity Non-UnifonnilY Effcetl' 

### (NHVN01' Non-UniforndW" 7%)

10

8 

### §. 6 c:i. &. 

### 4 r :2: 2

0 

### 80 

### 85 90 95 100 c1NOJc, %**---NH3JN~.** Dev2%

-0- NH3JNQ)(oSn:f. Oev4')b

-a-**NHS~~tI:1.** Dev5%

.....;r- NH3JNOx-Std. Dew6%

-.- NHSJNQ(-Sttl. Oev 9%

(b) N1I:JI'NO,. Non-Uniformity Effect:s (Velocity Non-Uniformity;; 10%)

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### reaction time. Equally**Unpo~** 

### iones oferosion-inducing high 

### velocity and 

### deposit-indncing low velocity are minimized figure 3 shows tlu¢ improved 

### velocity distribm:ian increases 

### performance. 

### but the 

### payback fot 

### achieving extremely "'fiat" 

### velocifYprofiles dim.inishes.
Figure 3 also show$ Ibe**NH3INO~** uniformUyis 

### significantly Ulore 

### bnponam: than. the velocitr uniformilY in providillg 

### for biSh**N~** 

### xcmoval. If

### anyone "cell" oftlue gas ifl deficient in either reacTant 

### (NH3 or NO). then The 

### teaction will noI proceed to completion

- 

### regardless of

### the \'olume ofcaralyst lha.t is 

### utilized. Pigure 3 also illusttatc=s**th~** criticality ofNH3INOl<.**U11iformi~** 

### increases as**NO~** 

### reductions exceed 90%.



### Most 

### elilfly genenmun designs in 

### Japan and 

### Europe are believed to 

### femure distributions of velocity of

### a IS-20% 

### SO, and of'NH:lNO 

### ra.tio 

### of 6% or**~r** 

### SO. The evohnion to high 

### performance**sys~ms** 

### requiring 90% 

## NOx removal at 

### 2 

### ppm slip has**te~** the 

### velocity distribution 

### modestly to 

### perhaps lO-15% SD, 

### bm**signifi~yfor** 

### Nfl3/NO ratio. The specified SO 

### for the latter 

### is :frequently less 

### tlWL So/o, aud 

### for some**~licalions** 

### as low 

### as 3%. As 

### a conaeque.uce ofthesa strict**specitlcations~** 

## seaprocess eqqip:menl: and Cat:a!Ylilt 

### suppliers apQ 

### ownel"S 

### have conducted.**~essi"'e** 

### modeling studies. Regarding 

### physicm "cold-tlow" modehn&

me scale ofnuxtel, (Jetail& of**constrn~tion** mcluded in the sbnula.li.Qt1. and extent 

### of measurements have significantly increased tIJ 

### support the high 

### performance systems. "!he use of CFD has 

### been integmYeC1 With**ph~l** 

### flow 

### models to 

### augment the evaluation, 

### particularly with 

### the disttibution oftlue gas 

### temperature.



### One item that 

### may become ofco:ucem is the abUitY to 

### OCUJStruet 

### and install 

### the**ammge~t** 

### of 

### 't1lnLing vanes, baftles l 

### mel tIow l"ectifiers to 

### ate 

### necessmy accuracy as specified 

### by the 

### physical

or 

### CPO model. Consuuctiol1 

### tolerances ofless 'than 

### one mcb. 

### may 

## me problematic in actUally 

### achieving the flow distribution 

### specifled by 

### me 

### model. 

### The challenge to 

### opmrors ofthese systems may 

### also be to insure 

### the process conditiollS,. once delivered. bytbe process supplier. 

### are JIlainta.ined. 

### Finally. as will be disCU5Sed snbsequently, 

### £imply demol:lSUating that**th~ stric~**  

### ptocc:ss conditions are actually 

### delivered by 

### the process suppUer lI1fly 

### be a critical 

### issue to SeR 

### operators.


### Reactor Layout

Reactor layout can vmy**~Y.** 

### depending 

### upon whelhl!I' 

## sea is 

### irunalled in. 

### a new 

### plant, or retrofit to an. exi:lting unit. 

### Comparison ofcontemporwy**r~or** designs to 

### early applications in Japan and 

### Europe is limited 

### for severnI reasons. Many 

### eudy SCR tetl:ofils in 

### 1apan 

### wc:rc "low 

### dust" lIJlplieations 

## mal: inherently required smaller cauuyst awl reactor**~olume.** without the complexity ofhandling lllgh dust**lo~ding.** Mmt.y

### boilers in GenmmyentplDY 

### tower designs, allowing a more stnrightforward**~tor** (at least in terms of 

### process conditiOIllh**ifno~** structural steel) 

### thaf

### was amenable to 

### improved performance. The flue gas 

### flow path for some towerboiler

## sea mrofilS could elt1pJoyperhaps twO 

### "'elbow' tUtUs 

### prior to 

### the catalyst,. which 

### a.trords good 

### flue gas handling practices.**CeminlY7!1~** ull European. installations are represented by 

### this concept. Md numerous challenging retrofits were 

### undenaJcen and SIlCOeSlOfiilly implemented.

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Ofuote 

### with US 

# sca applications is 

### the potential**f~r** 

### a larger fraction oftlue gas 

### ro be bypassed around the economizer. to 

### ,provide the open.ling "'floor', dge to higher flue gas**s~** 

### content 

### (from higher sulfur 

### coals). The relatively large volume oftlue gas to 

### be bypassed around the economizer over a Wide**J~** 

### nmge can 

### complicate :mixing 

### pauerns. figure 

### 4 depicts a 

### specifiC' rea.cror awl 

### duclWort layout in which 

### a relatively 

### large volume oftlue gas 

### exiting the**eCQno~er** 

### bypass 

### was problematic in. p1'\':Ivc:ntblg

## me disnibutiml. offlue p 

### remperauue and**"'~lQcity** to be**~usly** achieved. The**di,,~ion** offlue 

### gas around the**~onomizer** 

### necessary to meet the t.emperetUre specification. 

### biased the 

### flow field 

### aDd significantly**di&to~** me velocilY profile. For**~lc,** at mid-load the bypass dampers are only 10-20% 

### open and the**syst~m** must mix the small, 

### low velocity flow diverted around 

### t1le**ecoIlP~cr** with 

## me larger 

### bulk tlow. Conversely, at low load the b)l)8SS dampeni 

### are fully 

### opem, and 

### the system 

### must mix



### a hu:ge 

### volwne 

### oflarsc, high. v.:loc:ity 

### flow divened**~und** 

## me with a. 

### small bulk. 

### flaw. A 

### combination of

### phyaical cold !low 

### and 

### eFD modeling was usecl to specifY the derails of ductwork layout 

### and :flue gas recdfication devices. The**s~on** 

### was ultimately attained.

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### Reagent lnjecdon Equipment
Historically) the approach to achieving unifann mixWg**()fr~gent** with No,. is a higb-densil)' 

### anangemenr ofindividual 

### uyeetors acros:; a tlue duct. with as 

### many as**4O~50** injectors 

### per m2. The injectors can be individually ucljqsted to tl:mc the delivery 

### ofreagen;. In recent European 

### applications. the use ofa. small 

### number oflarge iqject01'S (4-12) 

### combi!led wiib 

### sonic mix.ers has emerged as an alternative TO a conventional ammonia iiljecnon grid (AlG). This concept is**receivin~** 

### increased**a'f~ntiou** 

### due m 

### The poQmtial 

### for reduced maintenance for individual itUectors. The 

### necessary**hani~** 

### and design expenise botb 

### me otfered ')mckagecr with 

### SOl**e~pmenl** 

### or catalysr. 

### and mdiv.i&mly from suppliers ofstatic mixers. Specifically. 

### one catalyst 

### IlUpplier offers two versions of

### a matie mixer 

### for 

### use in applicanons that employ 

### their catalyst.**SUniI~lY7 ()~e**  

## sea**proc~** 

### supplier provides delta-wings as standard equipment 

### in their 

### system design. Several individua! suppliers ofstatic mixers (Sulze=r. Koch. efC.) wiUprovide smtic 

### mixer r.ec:hnology as sumd-a.lone 

### offerings to 

### be incorporated into 

### the process design..

Recent US designs 

### have employedup f() five 

### individQal mws ofstalic mixezs to achieve a**reqt.rir~d d~triblf.lion**  of

### velocitY. rc:mperawre. and NHs/NO raUCi. For exampll!. static m.Di:ers lm" deployed 

### (1) a.t the 

### :tl.qe gas 

### economizer exit,**~o** 

### mcTify**imba1ance~** 

## m velocity. 

### temperaaue. and composition. (2) downmeam of

### the 

### take-otrduct for the bypitSs2 (3) prior to the 

### injectors, to 

### :rectify velocity maldistributions 

### maQce<l by 

### a tight 

### "elbow" tum. 

### required due to 

### space constraints. (4) 

### following the**reag~ injeclOl'S~**  to 

### induce mixing,. 

### and (5) 

### prior to 

### the reactorentry 

### plenum. The 

### nominal gas 

### pte:lSUre loss incuu-ed by 

### each row -less than. 0.3-0.5 in 

### w.g.- is the tt'3deofffor a COffCCt distribution.

In stmUnary. both the high density AfG and IItatic-mixer CO!1cepJs moe employed in US**appli~a.tions.** The need for 

### extremely 1Jigh 

### perfommnce 

### may mvorutilizing static mixers and 

### fewer injectotS etveJ' 

### a. conventional AIG. 

### Experience 

### wiTh 

### STanc mixers suggests that ifinsmlled cOIteCtlythe uuits will be :alaimenance-free, 

### opetatono are 

### predica.t:ing plans on this observation.



### Coal Experience
Early SCR experieace in 

### Japan domimlred Py 

### low 

## suln.r coals from Australia and S. Africa, the primaty coal.**.s~es** in the 

### llUe 19705. 

### Despite 

### The considemble undersnmding gained with these coals. generalization l"O EUI"opcan emUs was 

### greeJed 

### wiJh the: observa.T:iOn 

### oflll'Senic 

### poisoning at 

### pilot Beak. 

### AlJ:bough J10 

### episode similar to**~o** 

### poisoning is 

### anticipa;:ed fOf 

## us applications. the uncertain't)1 ofbr0a4**deplo~t** 

### to a set ofcoals merils lhat operatofS observe and 

### doeuwent composilion ofcoal tired to 

### relate opera.tio.ns to catalyst activity.**Tabl~** 3 summarizes the key coal**c<mstime~** 

### fha.t affect ea:ta1yst**deactiyati~** identifYing the most significant caJalYSJ 

### impact. Most 

### notable is t'he**ro~** of

### alkali and 

### alkaline earth elementS that 

### can induce alkali sul1ate poisoning. Calcium sulfate was early n:c:ognized as a significant deactivating agent (Ii) 

### the other more soluble**~1kali** cited can penettate**eataIys~** :{l(ll'es when exposed to moisture (ftom n:tbe leaks Of**conden~tion** due SUtNp). As described :previously, arsenic is a well-documentel1 poison that. although most acute far wet-bottom boi1crs "that

05/31/02 

### FR! 20:05 

### tTl/HI NO 7359]



### OETE0007523

### Jun-Q4-QZ QZ:44pm**From-~KIN** 

### & GUMP WASH OZ 

### + T-340 P.1Z!ZZ F-348

employ iilSh recycle. is 

### still problematic 

### for dry 

### bottom boilers with 

### lower furnace 

### ps exit temperatures.

Table 3; Key Coal Characteristics That Affect Catalyst Peacnvarion

COllI**l'~Or** JaplUlese**~OJlcan Atnici~US**  Consmuent Calal'iSt ImT)BCl"**~ah:nce 'Exodicric~**  Conditions Al'GeI'lie**:R.~** \Vim V. ncglil1Wg NcsljpJc rdeqtfficd lhtough Varies widt'ly with AS !tiu: i1etivh;y lllldIor As <:omenl did pilmandmly contem: in coal (2-40 bJockiQg mierOPQrtB nol**JdcQl:i~** cammetCiaJ ppm)

. DJ1S Alkaliul;: twlllee$ "!lcidiW- /Slid Taw3IkaU <S% TOllS! alkali S. .)J12% of ash, up to mUC'\il.\ {IC,**~c:aofQta1~** of

## am (obsetve4 lSOA! ofllSh 23%forPlm Na.Mg) llCmsiIes Wi1b oil bll} A1IusJinI: canb ReaclS wilh 

## so. fonnecl af**O~)-5%** 3-5% ofltlW. 2-10% uh, tlfHO 16% (primarily sil'o': to pt0412Cll**CaSo~;** ofCOlW fued' SlIllr YaHcy, lIIld forPRB C:.) pfaggingporcs. abilit;y at (Ausrralia, S. Polillh coaJs Nro {O &b¢ $iT.e. AiiCll} Mmim1m1 Ca aee&d lO nUu2ale 

### llnlc:sm:**ZlOisODiu~** Phos.pboTOQS AS pbO$pbQric aPid, elm**NOll"~4** lkcopi:.=din Will dl:pI::llQ on coal P condl:D8l:,**~,** and block**so~coaLi ~W14**  pores.**Dxid~Kc:\.1.lcing** conditioD:lo in**fUmac:~** Sultiu' I'ndireotly, ;sulfurprovides 0<0.6% <;1.7% 0.4-3.5%

uource ()fSO•• which COln**teac~** wh:b Ca lO foms**CaSo~**

Regarding arsenic) it is 

### known a minimum level of calcium**i~** We coal is desired to mitigate 

### afseni.c poisoning. 

### minimum level ofcmciumin ash (-2%) is**dcs~eq.** 

### PhOSphorous can also**~activate** catalyst. 

### a.w.! sulfut

- 

### although not exerting a direct role

- indirectly can 

### conlribute tlle 

### alPli sulUite fonna-tion 

### byproduction of

### so,. Figure S compares coals utilized in. the Japanese and 

### European experience wiTh those 

### anticipated 

## us applicatious. figure 5**CQmpa:r~** the content

## of(a)**SUIM~** (b) ash, (c) calcium. in the fly ash, and (d) tOW alkalinity of.t1y iISh constituenTS (calcium, po'(&SsiUIQ, magnesium., and sodium). 

### Figtue 5 shows**exp~em:e** in Japan derived 

### wilh relatively low suttUr (",,(),4%). 2-3% calcium in 

### ash, and 

### nesligible soluble**~j** 

### compounds. The 

### coals 

### Use4 in Burope f;ypically feamre double the stdfur**~tent.** 

### and**iDcr~ed** caJciuJn and 

### lOtal alkali in fly ash. The 

## rUSt us SCR imtallalions were on low 

### sulfur coals 

### that: (due to 

### compauoility with dxy 

### scmbbing technology) resembled 

### the: coal used. 

### in Europe. The 

### complete set 

### ofUS coals**tha~** 

### will see SCR duty in 

### the US may 

### present greater**cballen~** 

### than the first 

### coals did, 

### due to 

### higher sulftn- and. in


### some case Fe**~!1tent,** 

### which win incr'ease SOs production by the cam1yst. For some coals, low calcium content in fly 

### ash may 

### be inadequate 

### to negate arsenic poisoning, and 

### adding limestone

or other a.lka!i to the coal will be required. 

### Finally, the case ofPowder ltiveJ" Basin (PRS) coals 

### may be ofconcern, depending on the application. Short-term exploratory tests suggested the
extreme calcium content ofPRB promotes aUcali sultme poisoning. B.owevet. oOt all catalyst

05/31/02 FRI 20;0& lT4fRX NO**7~591**



### OETE0007524

### luu-04-0Z OZ:44pm From-AKIN 

### & GUMP WASH 02 

### + T-340 P.13/22 F-S48

supplic::rs shme fhis**view~** and 

### the 

# mt**commel'Ci~** 

### insUlllation with 

### PRE coal has not incurred 

### any noticeable 

### dc:ac:tivation.

Figure 5: 

### Com.parison Of 

### Coal Characteristics For 

### Japanese, Buropean, And Anticipated US Applicmions



# J

14.1lll

lUln

010.011 

# !aoo 

# J
&.OP

Z.OlI

0.00 f- .SUJur

I--**.~** 1--"" QCaIcIuM D TOIaI AIkslIne I-



## ...

,..

t-- f--

# ~. I",

# .~ .II: 

# • • 

# ..

- Awlll'AIIll S. A!l1lllk:l1/1 Ruhlt11 !Illllr{2) POIOIllI llullllr MIlQ SwIlur tflIIIl s

..nur PRll**~~**



### In sumtrWY, some US 

### coals are not describc:d 

### by

### the existing 

### experience daTabase, and 

### despite the beSt 

### effons of**ca~ysJ:** 

### suppliers, some risk

### to deactivation at 

### balance-of-plantproblems exists. 

### Reagent Type aud Systems

In comparison to early SCR. 

### applications, which were limit&:d to 

### solely anhydrous ammonilJ. as a fl:2gent soutee:, present 

### applications C8I1 

### employ 

### either atJhydrous, or aqQCOus fomlS ofammonia (of 19.5 or 29% soll.Uionstrength). 

### In addilion, dClJcnding on**th~pt'Dgress** ofsevera! early 

### demonstration projects. urea may be applied. From sltict1;y a cost standpoint anhydrous reagenr is 

### usually preferred. 

### as it 

### requires 

### the least delivered**cos~** and 

### capiral equipment. However.

concerns voiced by 

### local co1tl1U\U1l.lies ba.ve promplOd adoption ofaqueous reagent for many 

### systems$ and for on a limited basis.

In 

### Europe, the:LUst iustallalinus cmployad**rea~ent** 

### receivin& srota.get and 

### handling**~s** 

### that employed 

### consefVmive measures such as UlUlergwund 

### ta.ob" double-wall and numerous tail-saCs monitoring**concep~.** A:il 

## sea applications migrated from.**Iarg~** remotely locatM ceDtral stations to uniTS in urban ateas" U1tel'est in aqueDU9-M'Jmonia. roagenl: incTcased with local
concerns for bandling aud sromge. Anhydrous systemS**app~** to domina.le planned US

05/31/02 FoRI 20;05 

### ltI/RX NO 7359)



### OETE0007525

### Jun-n4-n2 02:44pm From-AKIN 

### & GUMP WASH 02 

### + T-340 P.14/ZZ F-348



### installations, although numerous aqueous .systenlS 

### will be Ulilized. Urea:-based applications have received 

### recent intc:rest. In terms. 

### ofimpacti.ng SCR**operatio~.** 

### the use ofaqueous and 

### m:ea systems introduces additional 

### complexity. 

### SpecificaUy. both approachl:S require a sepamr.e vaporization step, which entails additional process reactors. an4 managing and 

### monitoring the Ieagcnt 

### devolatilizalion. or

### hydrolysis proces$. The manpower bU1'den for such 

### m.cmitoxmg is not significant (with much ofthe duty**remo~1y** 

### monifored), but lhe 

### addiJi.oual steps for 

### evapotatiQn oftmUnOAia**~om** lbe aqueous foIDl, or devolautization ofHN hgmcms from. utea introduces time delays that must

### be**~unr.ed** for in 

### proceSli control 

### system design or operation. With target performance of90% standard 

### and:aecess;uy for system**compl~e.** thest: 

### factors must be 

### considered in 

### control system design.**Balanc~f** 

### ...Plal1f

A dewled**tr~unent** ofba_e-of-plant (BOP) factors is outside thl: scope oflhis paper; but several key items afC 

### ic1enlUled.

Most European uniTS 

### were initiallyeqtli.pped 

### with enam.eled-coated heat exchange baslcet:i in 

### the cold end of

### the 

### air heiner, and lbus eqjoyed superior 

### PJ'0teCuon from the additioIUll, SCRpromoted**S~.** 

### The use of

### enameled-coa.tedheat**excl1~Ge** 

### bPSkets 

### is 

### not 

### commonplace in 

### US applications; howe\'er Cotten is 

### frequently used for 

### higber sulfurcoals. An infonnal SUlVey 

### suggef3ts that 

### approximateLy 75% of the units retrofitting 

# sea in the US an: believedto 

### be upgIaCling air heakl'S to mitigato the impact ofresiduaI 

### NH3 bigber S03. These modifications**i~clude** installing**enamel~d surftlces~**  ulilizing A more "open" geoxm;try to reta.Ul 

### the moment'UIn ofsootblowin; media. in the 

### axial**di:rcctio~** 

### or horb (1). 

### The evolution 

### ofSCR process equipmenl has probably eased airheater coucems, as experience in Geonany in the mid1980s 

### suggesled residQal should 

### be lowered from 5 to 2 ppm.. for the putpose ofash 

### utill2ation. The potential for air heater depDsmOD 

### has been reduced accordingly.



### Flue GR$ Handling



### The need to retrofit 

### adc:1iumml tlue gas flow 

### capabilit.yto 

### hamUe the tdgber 

### resistance imposed 

### by the reactOr and process equipmeut varies sigpi:ficamly wiTh sper;jfic mUtS. 

### T}'Pically. the additional resistance ranges from 3 in. 

### to7 in. w.g' l 

### depending on the application, wilh mo:>! instalIaticms probably incumng 

### 4-:5 in.. w.g.. 

### It bas been 

### widely**~ned** 

### that most 

### European insmllaTions did not require upgrade to 

### flue gas 

### handling**~ent;** 

### however, the nationwide program. tel 

### relI'Ofit flue gas**d~on** 

### processes completed

# m 1984 {3} requitc:4 fll.le gas bandling 

### upgrade that in 

### many cases 

### was able to also accommodate 

## sca. Ar:l. 

### informal S\lIVey 

### suggests that 50% 

### oftbe 

### units re:tmfit 

### with SCR 

### ill the US 

### requite some improvement to 

### flue gas handling, with upgraded motors Of fans C011U1lQn.. 

### Compared to pieVious ex.perieJ1ce. any

### reductions 

### in 

### tlue gas remtaDoc by 

### improved catalyst desigD have probably been absotbeq by static 

### and: AIG components to provide a more 

### etfcctive 

### NH3/NO distribution

- the price for 

### wmch is 

### paid in**pr~e** 

### drop. 

### Thus. the evolution

05t3l/0Z PRI 20:05 [TX/RX NO 73591



### OETE0007526

### Jun-04-02 02:45pm**FrQm-~KIN** 

### & GUMP WASH OZ 

### + T-340 P.15/ZZ F-348



### ofSCR. application bas 

### probably not materially cluulged Ibe 

### addUional flue gas l1andling**requirements~** or associated O&M.

Since arsenic 

### poiscm:m.g was demansnated a lWlior contributor to catalyst deactivation, the need for 

### a. minimum. 

### quantity ofavailable calcium in 

### The 

### fly ash has been recognized. SeveI8l 

### European 

### operawlS oonsistel1tly inject 

### or 

### add Uw.esnme ()l' 

### lime to 

### coals med to 

### augment the namrnllyavailable calcium 

### in. 

### the ash, and claim ft. 

### benefit 

### in mitigating both arsenic poisoning and**S~** 

### outlet com:e:nmmon (3). 

### Generally. 

### anywhere from 0.5-2% 

### ofmes coal mass 

### eousumplion rate is 

### augmemed widllime.**dokJ~lic limcs'Ul~.**  ()f 

### conventional limestone TO**pro~de** 

### alkalinitY. Capital COstS 

### for such 

### equipment are l10t 

### excessive, but O&:M procedures m\1St**~commodale** servicing the 

### aUca1i supply an4**~pment.** The eJttent to which such systems 

### will be 

### applied. in the US 

### is tmema.iu. One IIllUot

## seaprQcc:w equipment supplier strongly adviseS 

### deployment

### of:ouch cquiplDCnt:. au4 

### most (but

### not all) cafalyst 

### suppliers agree that 

### fpr certain**~plic$ons** 

### the addifional is beneficial. However, Southern Company recently**anno~ed** 

### they would forgo 

### albli**addiU~** and**~t** 

### pos:iib1yhigber Cilta1yst 

### deactivation in excbange for simpli(:ity and teduc:eQ. plant operating

### 4mies. b1 SUlImUliY. the need to inject 

### alkali to 

### mUigtUe 

### either

### memc poisoning or control SO, 

### emissious 

### may slightly 

### increase O&M, but 

### adoption ofalkali iJUecnonladWtion is !lOt

### anticipated to 

### be widespread.



### LONG-TERM OPERATING CBARACI'ERISTICS
Operating data obtained fur 

### coal-tired SCR-equipped units 

### shows tbatperfunnance can vazy over relatively 

### shan perinds 

### ofti1:ne. Given 

### thai 

### the:**N~** lOJl.S cap 

### fat the SIP-Call is e!feetively a 

### 5-mondl average. 

### hourly or daily 

### variances will noT: be 

### ofsisnfficance for many OpeIatotS. 

### However. in 

### adliition to 

### the**S~~** 

### (or annual) tOns cap, 

### some states require some combination ofa 30 day. 24 nour. or 8 hour rolling a\1e«lgc fO be observed. Specifically, sevend sea

### equipped qnits 

### planned for operation in

### tlJe Houston are=a. must o"bset\Te 24 hour daily 

### averages of
a magnimde 

# mar are not**~gni1icandy** above the 

# aunum cap.**~.** 

### new SCR-e:quippc:d tmilS 

### will in 

### alllikdihood be 

### requited 

### to abide 

### by a shmHenn average. Data from the Environmental Proteetion Agency's ElCCQ:onic Data**~g** (EDR) site is used to explore the vltliabilifY 

### observed in 

### the US TO 

### dafe. 

### Figme 6 presents**typi~** 

### scauer in 

## sea ouTlet data, obPtined tiom 

### a <lIy

### bonom. boiler in 

### the US with 

## sea operational far several

### years. The 

### clafa. pteSlm18**N~** 

### emissions within 5% oftblt 

### load. 

### The di:ta.ils of openmOll 

### and the mtel1l 

### oflbe OP"'lS 

### are 

### unlmown; thus it 

### is not possible to detennine the source ofvariability. However, 

### it is clear

### the op'ri:l:wll amount of reagent required 

### by a particular 

### Qfprocess 

### condiuons is 

### not 

### consistently delivered to the 

### reactOr.

The variation be 

### quamified by a.pplying**ma~** 

### pr0ce4W"eS to 

### calculate the 

### 30 day 

### average, a 24 

### hour average, and 

### au 8 hourfOiling 

### average. Figare 7 compares this dala 

### fur four unitS. Two units are 

### 4rybottom boilers retrofit wilh seR far bigb**N~ ~ovill**  

### trom**~pproximately** 0.45 lbsIMStu (UuUs A aud D);**g~** cyclone boiler designed for 80-85%**N~** removal from 1.2-1.5 IbsIMBtu; (Umt C), and a**D~W pl&n~**  capable of**5O-600~** 

## sea**N~** removal 

### from 05 lbslMBtu (UxUt E). 

### The dafa iu**Fjgut~** 

### 7 show U**NO~** 

### tYPified by 

### shon-Term

05/31/02 FR!**:o:o~** [TX/RX NO 7359J



### OETE0007527Jun-G4-GZ GZ:45pm Frcm-kKIN 

### & GUMP WASH 02 

### +**T~340** P.16/22**F~348**



### avetagiug pcrlQas 

### can be 

### significantly than lbe**caU:~** 30 

### day rolling average. These dara. caJ1 

### he used to 

### estabJisb an 

### "'opemiD$ marginn 

### NC\. OUtlet that 

### should. be 

### latgcted if**short~tem1** compliance 

### is 

### required.
Figure 6: SCR Outlet 

### Emissions Panl Scatter For 90% Removal Systenl

(l.S

Cl g 

### " 0 6 g 0.5 (I 8 (i Cl 

# 1

0

•

4 II

Q 

## 0°

Q C (l q, <I 0 (l

## ~M Q {/
Q (I 

## i 0 0 (l 0 

## it 0 0 Q 8 Cl 1:1

0.2

0.1**1~O ~~**  2&ID**3~' PROGIre~liguR5**  QF OPImA'trON

Figure 

### 7; Comparison of30 Day, 24 hour: 

### and. 8 ffour**N~** Outlet Data for Selected SCR

### Equipped Units

UN!TP uNITe IJNffA lur 

# !

Z4Kr 

# 'Ile

Z4lfr

3004 IUlr 24-1fr**~l)lI** .wDa



# - 11K!" r- rZtrlr**~PlI**



# .. ""'-" 

# n



# - '- 

# -- OAO

OJlO

0$/31/02 FRI 2Q:05 {TX/RX NO 7359]



### OETE0007528

### Jun-64-6Z 6Z:45pm From-AKIN 

### & GUMP WASH 02 

### + T-340 P.1T/22 F-348

figme 8 complU'CS this**~matgin"** for the foW" units cited, 

### in addition to 

### a second cyclone unit (Unit E) and 

### a. second new unit wifu 50% No,. capability. This fipe depicts the wide: variability in SCR oulletNO:!: from UnitA; howe\fet. ai 

### the**subj~** mrll has opetatedwith 

## sea for less 

### Than one 

### year, the results should 

### be 

### considered prellmiQaty.**D~** 

# mnn mos: afthe other 

### units suggest 

### operatOrS may be 

### required to 

### co:oaider a.ocJitional monitoring 

### activities to align shorrer and**lan~r** term rollinS avemges.

Ofnote: is tha.J the least 

### \'ariabilil)' is exhibited by the unit that (a) t'eafQres the longesT opemling 

### history, imd (b) 

### rcctuires the least NOx 

### reduction. It is not 

### clearwhicb, if

### any, ofthese factors is responsible for 

### Uris Qbservmion.

.


### One must be cauti01!S with 

### Figures 6-8. as opetatins time is 

### limired for some uniu. anq. the 

### intention ofthe operatOrs is 

### not cleu' (e.g., 

### minimizing sholt-Tem1 variability 

### may not be impottet). Regardless, the**data.~1hat** precise**~lionlO o~g**  dlmes and 

### development ofa,leaming 

### curve are necessary for successfW. PfOCCSS 

### operation. 

### the results also SUggesf that" lUly sh()tt-term. monitoring requirements by local**~em:ies** consider prncticallimits
to 

### process operations.

Figlll'e 

### 3: EsUmate ofOperadng MatgW. 

### Req'Uire4 For Six SCR-EquippedUnits

!

i : 

### I



# . I

: 

# I
!



### ._-



## -- . 

## -- 

# I I



# -

I) II '00

05/31/02 FRI 20:05 

### [TXlRX NO 73S9!



### OETE0007529

### Jun-04-0Z 02:45pm From-AKIN 

### & GUMP WASH 02 

### + T-340 P.18/ZZ F-348



### IMPUCATIONS FOR US 

### O&M ACTIVITIES
Essentially all majorutiliw 

## systems are deploying 

## sea as the 

### ccnttal element in their 

### NOx cootrol strategy, and

### plan l'Q 

### "overcontrol"**N~** 

### on tbe largest plants. al10wiDi smaller, lower capacitY 

# memr UnilS to adoplless sn.inge:nt oontrols. The success ofeach NQ.. compli<mce 

### program is heavily dependent 

### on slICCeiSfUl opeJ:auon 

### ofSCR 

### at W'Set levels.



### Maximize**NO~** 

### Removal

The 

### previous discussion. shows IeprdlesS ofwhetber a. 

### CQuvemional 

### AlG Or 

### smic mixer system is utilized. achieving 

### and maiInaining 

### extremely uniform contacting ofreagent 

### an<! 

### NO is 

### necessaty. Testini 

### on an annual basis will 

### be necessary to 

### determine the 

### inlet and 

### outlet NO,. dism"buuon to infer lhe 

### NHa/NO Qtio afthe cmal}'Sf 

### inlet. Many Eufopean utilities conclm:t lhese 

### exercises on approximatelY an ammal**ba~** 

### which is reconnl1euded for 

## us applieatious. With conventional**hi~** cL=nsity AlG. considerable flexibilil.y is**av~1e** to hias**rea8~t iJlJec~n**  ;0**diff~** regions of

### the duonvcrJc. Using**s~tic** 

# em« alimite4number ofinJecwrs limits


### me flexibility, 

### b1lt not: eliminate the 

### ability 10 

### bias 'Che 

### reageut. Process suppliers claim the mixiDg capabilities ofstatic miX=s**elimina~** 

### any need for flexibility, bm: only c=xperience 

### will prove so. Regatdless. rhe scale ofinfluence ofswic mixers. is limif.l:cl, and compensating for 

### large-scale variations 

### (e.g., across ihe 

### entire dUC'miQrk) m'*}' not be possible.**Th~s.** 

### even.litcited injectors with static mixelS 

### may tequire attention.

As di:>cUSsed lUlder I&C,**m~** lowest SeR outlet NOxlJ:la.y be attained with a boiler NOli: output optimization for distribution, not uecessal'ily tbe least ma.gniPoJdc:. Consistent testing of inlet/outlet**N~** profiles 

### will identitY optimal opemnng mOdes.
Catillpt Maintenance

The need to achieve high perfonnance requires 

### cm:a1yst to retain activity as projected by the 

### sllpplier. 

### As both**physi~** blPcldng by fly 

### ash 

### aIU! 

### a JCduction in 

### sue**acrivi~** 

### (du.e lO 

### arsenic, aJka.li sulfate 

### tlnli other compounds)**contri~** tQ**deacti~onl** iuspection**~d** cleaning a1"e 

### critical. The ofcoupon tests 

### conQuered l1y me catalyst 

### gqpplie:r (and 

### possibly 

### a third PartY) is essential to provide a**snapsho~** of

### change 

### in cmalystphysical features 

### and surface composition. The inspection and 

### c1eanins of

### eata!ysJ: during outages will be**~es5my** to assure 

### mar the: nwcimmn surfilce area. is clean and available to participate in**'N~** reduction..



### Data Historian
Operators will need to document me process**op~ons** 

### and coal COfIlposmon rigorously fa 

### vaIi.dme 

### thaT 

### the 

### condiMns of gmuanteea have 

### bee&1 observed. All units to 

### some degree require this, but particularly those**opera~** l!lat have 

### securea a ea.talYBf supply**C()~** separale from the process supply CO!llraCt.

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### + T-340 P.19/ZZ F-348

Many utilities have e$bli6hed 

### strategio**aUi~** 

### with a 

### eautlyst manufacmrer far caralyst: supply for an entire system.. 

### The**se1~tion** 

### of the particuliU" supplier is**b~ed** 

### upcm a 

### firm cost estimate to 

### provide adequate eatalysl: 

### volume fa 

### achieve 

### aprojected pedomumce target, prestllcing 

### a. fixed. !Set 

### of process conditions. A 

### separate COIltraot 

### is aoanged 

### with a process supplierto provide the equipment to**~nvcr** those process ccmdidons.

Under this scenario. it may not 

### be snaightforward to 

### attribute responsibilitY for 

### ma1perfonnance. 

### For exam.pie, ifpedormance tal'gelS ate 

### not satisfied. it 

### is iilnticipaled the**oata1ys~** 

### supplier will ntst:**~~** demonsmmoJ.'l. !hal ptocess conditions called for in the specification have been 

### delivered- pamclllarly iftbe caJalym 

### supplier 

### was IUlt the**~ponsible** pany 

### for flow**mocl~.** 

### Howcve:r, measuring 

### velocitY disItibutionin high 

### temperature, 

### particulate-laclen .flue gas to within me a.cCtmlcy 

### required may 

### nOt be 

### viable; thus. it 

### may 

### not be 

### possible to 

### validate process**eollditio~.** 

### Regarding coal composiCW!lt e:atalym: 

### suPPliers 

### wilt lequire 

### asSW'a!lCe that coals 

### as spec:ifie4 are utilized; for example;. it wJ1l 

### be important to 

### documenl thal 

### a. miuimum level ofcalci1Wl is available to 

### miuga:te anienic poisoning. A**sys~c** 

### a11q cOlllfOUed 

### melho<fowgy to sample and**amUyz~** 

### coal. using a.greed 

### upon pn>toCo!s. is 

### necessatY 1'0 

### eonatt'UCt au 

### adC:'luate ammgemeut:. 

## System Wide Catalyst 

## Management

The use ofsevernl 

## sea facilities across a**~tmg** 

### system aftbl'Qs the 

### oppommity to employ a systemwide**appro~** 

### m catalyst**numagemc:n~.** Even though a 

### catalyst layer 

### may have suffered 

### deactivation**~cc:ssUaliug** 

### replac:ement, that 

### specific**la~** 

### can still 

### prQvide adequare 

### NOx removal- as 100& as the reactor has been designed 10 accommodate the lower initial activity. 

### Also, catalyst**rc,gen~tion** 

### teclmiqut\S can increMe aetivi.tyfo! a cost below new catalyst. 

### Systemwide camlyst mmur-gement hl:JS beell 

### deployed at seveml stations in 

### Germany, and**r~eJ1era.tion** 

### lecbniques have evolved in 

### recent: 

### yeaIS. Several providers 

### ofcatalyst recycling 

### services have 

### refine4 

### Uleir offotings and 

### m-e plamling to offer tiUch services for**~he** 

### U.S. market. Bach 

### regcmcration tc:c1mDlo;y is**differe~** but 

### appears to 

### uufizc a combination 

### of(a) physical 

### cleaning to l"elnove**~h** adhered to**ca.talys~ ~ing**  

### resistance to 

### mass transfer, (b) washing 

### witb. an aqueous or nOlmtpleous Solvent to 

### enhance removal of

### ash. or removal ofsoluble alkaJi suliate compounds. and/or (e) inn"o4J.lotion ofadQitional vanadium on tbe ca.hl1yst 

### service.

The 

### potential benetirs of a sysremwide ea.tal.yst

### management strategy 

### can be**quautiti~** by 

### a simple example. CoWiider a. 

### three-unit syatem 

### employiQg a large**~natipn** (Unit A) 

### equipped with


### a 3+- I 

### reactOr design, Units B 

### muJ C 

### are also equipped with iii- 3+1 

### reactor desigu, and each offer 50% 

### ofthe genetating 

### capacitY (and catalyst 

### inventorY and tepl#c:emenf**~quUements).** AU units fire 

### a modentte-bigh 

### m=c con«:nJ coal•

### .install 

### the 

### founb layer at 

### 16,000 

### operatinghours. 

### ana (when using m:w**eatalys~)** n:place**existin~** laycn a.t: 

### mletVals of**appmx.i~tely** 18.000 opernting hours. ('Spent" catalySt from all units is 

### "pooled" 

### faf**resenemi~** elimiuaring the need for new catalyst 

### after the 16,000 

### hour supplemem: and 34,000 bour repbwement. Camlyst: 

### regeneration tcclmology is 

### assumed to restOre activitr (kIko) to 

### 0.85 fOJ' 

### 65% ofncw cawyst: cost:.

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Table 4 summari2es sysJem catalyst Jnlmligemem over" 15-year

### per.iod. assuming seasonal operntion for

# me inilial fouryears and annual**op~on** lhereafter. The: Baseline Case requires a total 

### of18 mye;s 

### ofnew**~no** be 

### plU'clwsed for aU UUifS. 

### at 

### a. NPV of$11.4 M. The Regenera.tion Case 

### red.uces 

### total new eatal:YStpun:lwsed to Slayers, 

### with 

### a. total 

### of**141~yt!!s** regenetated. The use of

### emalY8fl>floweracQvity requires cmc additional layerro be exchanged 

### for Unit 

### A, 

### over 

### me is-yearperiod. TmaJ incur.red costis reducec1 

### by almost 

### 20% to 

### $9.5 M.

The scenario descnbed 

### iJl Table: 4 is necessarily simplified; and selecJ:ed to emphasize the**benefi~** QfeatalySt:regClJera1ion. 

### Specifically. the assumption ofmodeiule-mgh arseuie content 

### coal requitd -rehmvely fi'equenr Jeplacement. 

### Also. the scenario assumes success 

### in restoring activity for- 

### lU'Senic-poisoned**~talyst;** that camlyst layeu 

### can be 

### regenerate4 m.ore than 

### OllCe; aDd that catalyst deat;fivaUQJ1 rate after rc:genem:ion 

### is 

### The same as fur new caf8lyst. An actual ClUalyst management strategy wiD require balancing ofreacfOt**po~ ~quired**  vc:rsus the generation Qf"spent" 

### camlyst, an4lhe cost and performance 

### oftegenenl1ion tectmologies.**R.egafdless~** the 

### poTeu1ial benefirB are notable. andmerit ao 

### independem an;l1ysis of this 

### alternative to 

### purchase ofnew caMysr.

Table 4: analyst Management StralCgy 

### Iucluding**~8eneration** for 

### Hypomenca1 System

Total Cahilvst Mana2lmlcnt: FaclOr' UllitA UnitB UuiiC Systefl1 

### Reuetur DesiJm 3"tl 3"1-1 3+1 Initial CataIysrJnventoIv (c..m.) 500 250 250



### . CaTalySt Pcr Laver 250 125 125

BalieUae SWate2V**Ca~lysfPurcbase4** (IS years) 

### 61ave:rs 6 layers 6 lavers 18 layers NPV OfCata!vSJ**Mlm~gemmT($M}** 5.70 2.85 2.85 11.14 ReeeJlention Case New CataIvst Purchased 

### Ilaya 2laveJ.,; 2 layers 5 lavers CamlvstR.e dOSVeafSl 61aYeI$ 41ayers 4la.vers 141ayeIS 

### NPV OfCa1alvst

### Manaeement ($M) 

### 4.78 2.35 2.35 

### 9.5


### Improved I&C/Controls

OJ\e**/ilfea.1ha~** has not 

### notably evolved, butwith significant potential. is 

# mat ofprocess cm1'lrols. Current SCR. processes employ 

### a. 

### feedforward. signal for reugent demand (based on boiler NO>.. aT a SUlTOgate 

### such as loild or steam :Bow) 

### with a feedback signal, the 

### Iauer base4 

### on measured 

### outlet NO); at the teactOr ex:U 

### or staclc. 

### Numerous operators have attempted to 

### couple a**OOIltWtJO~ on~1ine**  ammonia monitor as an a4diUonal 

### feedback signal, burundI 

### recently such 

### insmnnents have 

### notprQVitJed commercially acceplable**servi~.** 

### In practice, a residual NH3 monitor may**no~** proVide significant value over infeniug ammonia**absOfb~** by fly ash. Iftbe deposition ofammonium 

### su.l&les 

### lWet bisulfates (ABS) is a phenomenon dependem on cumulative. long-term and "low level" cxpoSW'e to residual NH3 and 

### SOJ. then**monit~ring** 

### BmIQDma. absoWc:d 

### On 

### fly P3h may be: 

### adequat<:. However. ifprocess upsets and 'llooaillg"**of:re~iQual** NH;s is a contribUTOr. then-a teaHime monitor will be

05/31/02 FaI 20:05 [TX/RX NO**1~591**



### OETE0007532

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### & GUMP WASH OZ**na:;1.::1~ U~**  1.1

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### + T-340 

### P.Zl!ZZ F-348



### useM. As 

### ADS deposition depends 

### on flue gas 

### SO:,**conce~** 

### it 

### is likely 

### Ihatlong-term**e~sure** is 

### dommant Perhaps more imponamly, the need to maiDtain 

### The UDifQllUity 

### ofNiWNO ratio to St1i11da.nt deviations**of~low** 5% 

### may require cannal ofthe boiler NO;.; emission distributioJ1.**Specifically~** opemron> may fuJd to achieve strict SCll**ourle~** mrgers the boiler should be operated
'to produce the moSl unifoun, and llOt: necessarily the**low~** NO x tale. For eJCarop1e. a boiler**NO~** outlet of().35 IbslMBm. cbaucreri2edby a 3% SO may be preferable to 0.32 Ibs/MIhu characterized by a 6% SO. jfOOOh removal 

### is to be**c~tent1y** 

### acmeved.
finally, consistently delivering 

### 90%**N~** 

### removal 

### may benefit from 

### upgrade aime**~ection** 

### system. (either conventional 

### AlG or auu:ic mixer cnnanoed.) 

### from**pas~** to 

### active 

### control. NQ.. distribution profiles generated during operation with a penna.nent grid may be 

### coupled to a series ofcont.rol valves or other**m~** to bias

# reasem**~ss** the 

### stitt. Although implementing 

### this concept is 

### not 

### simple. the additional COSt 

### aDd 

### O&M COf.l1d significamly

### levmge the fixed invesU'Oe!1t in SCR.



### OBSERVATIONS AND CONCLUSIONS

sea tech1'lolagy has 

### evolved. 

### COJ,lSiderably in tbe 3lmast 

### 25 yea1"S 

### since the first 

### commercial 

### demonstrations in 

### Japan. Equally signi:ficant 

### me**~e** 

### oime applications 

### and design 

### requirem.ent5 

### oime 

## sea insTallations for 

### me SIP-C6U. has 

### increasecJ, with 

### 90% removw 

### and the 

### need for N;fuINO 

### mtio as low as 3% SD. AB a ccmsequence, enti'fe geneta"dng system. NO;r< 

### compliance 

### suaregies depend 

### an suecessfiJI**~loymcnt** 

### oftbe SCR. And lackint a.tobust NOx allowance m.arket (at 

### least b:t 

### me 

### early years), 

## sea s)'Stempetfo:muwce win 

### directly impact 

### the geuoIa'tian 

### available :from 

### anyone unit in 

### a season. 'The fonowing 

### observations offered regtU'ding O&M 

### activities preserve the OPCl"8tiOJl 

### oftbese sysu:ms:

L Design Margin. 

### Both competitive 

### madcet forces and the use ofcatalyst management strategies that 

### mi:o.i:mi2e least fum cost 

### probably leave less design margln in catalYIU sizing 

### (compared to the Japanese aud

### European experience), to "insmc'" against vnforeseen events. 

### MoniTOring process panunetelll 

### is essential to 

### understand 

## sea operation., and detect: 

### any problems early.

2. 

### PrcuI&:ti"e Diagnostic 

### MeuuremeDts. Effotts to 

### detennine the 

### disuitnuion ofNlliNO Iatio 

### and othel' key 

### pfOceS$ 

### <lpetaUng**~cs** 

### are essential to mamWning nigh 

### perl"()tIlWlce. Although 

### Time-eonsuming and cumbefSOme,**~blishing** 

### 1be 

### grid ofmlet and/or outlet 

### N01o. from which one can infer the 

### NH:JNO distriburion 

### will be useful. Also 

### important will be inspeetiQa and**ev~on** ofcam.lyst deactivation (possibly including 

### a third pany) during the: 

### annual outage.

3. Sllort- Term sea OlnteJ NOx YariabiUty. Actual NOli. 

### outlet data can vaty widely 

### over**~or;** periods oftitne. so that an 8-hollt rolling average may be as much as 200% above the 3<klayavezage. For units thar: must obsuve So strict: sbort-terIn avezage in addition to a 5- 

### month or annual NO. "cap11, 

### a "target'" 

### should be determined to 

### assure compliance.

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4. Data

### Bbforian. A"d= bisrorian" activity willbebeneficial to 

### the owner/opentor 1:0 

### uack and document key opetating**~tBrs,** 

### iDcludiug coal 

### supply. aJJd evtUuation oftrends 

### betWeeij 

### proceslS 

### operation and coal 

### cbaraeteristics.

5. CaJalyst 

### ManagcmJcut Opdou. Catalyst**m~t** options are numerous, 

### panieularly


### across a llMty 

### operating system. 

### wbcmeata1ysr

### canbe intcrclumgt:ld be&wemunits. 

### The abiliTY**~o** 

### regenetam cawyst 

### should. be evaluated by**degr~** 

### ofactivity restoration versus**C~** ami the Det 

### sa.vings ava.ilable within 

### an entire: system. Openltol'S 

### should consider an i;Qdependent 

### assessment ofsystem wide**~atalYSt** 

### m=gement, inclUding competing regatetation options, in. 

### addition to 

### new eatalysf

### pUtCbase.



### 6. l&C Improvements. VarioliS improvements to 

### I&C systems 

### shoUld be considered, that are logical exte:usions to 

### lever4ge 

### the**inv~** in 

### Sell TO extract 

### addiliomU N0l> tons. Such**sysl'eU1.~** 

### may 

### not be optional**bu~** 

### necessi1ies. if

### additiotml compl=dtY 

### introducedby aqueous/mea. rea.genl systems tndlK-"\: LiuJg**l~Ci** 

### into j&C**G~.** TheSe actions may not necessarily be**ap~v~** Pu.t comprise a4ditional duties 'in a ccmpl:titive matlretplace that are essential to presexve plant reliability.



### REFERENCES

l. H. Zinder & Associates,. 

### Evaluarton DfThe Cosr 

### Of Sale COllrrol

### Strategies In The 

### SIP-Call. 

### fmal reportpreplU'Cd forfbe Midweit 

### Ozone Group, October 16,2000. 2. NWibayashi. 

### Y. Research 

### andDqyelopmen'fon NO" .Removal 

### in Japan andRaul1s 

### oj ERIX: 

# s .Research and

### Develop11lf4nt**~fdw J)eNO~**  PrOCf!SS;**~edings** 

### ofthe 

### Second NO" Control Technolagy Seminar. EPRl**Sp~ia1** RepOll, EPRIFP-II09-SR, July 1979. 3. 0.>

### Applicarion 

### OJ**DeNO~** 

### Tec1mol()g;es In The FederalRepublic**()fG~a"J'.AmI** 

### Europe. Proceedings OrThe 1$ISS Symposium On Sumomuy Combustion NO);. Control. 

### Volume 1. Utility Boiler Applications. EPlU CSa4360, Volume**l~** JamlatY 

### 1986. 

### 4. Engelmeyer, 

### T., Orlando fJlili'lies'Experience with SCR AtSramon Unir

### 2, EPRl 

### seR Workshop. March 22-24. 1999,**Or1ando~** 

### FL 5. Cichanowicz. J .E., 

### AnAsse.rsmem of European Experience With Selective C{ltalytic Reducfion. In Gtrrmany andDenmqrk. Proccedinp 

### ofthe 

### BPRJ..OOE-EPAAir 

### Pollution Control Symposium- The Mega.**Sy.m:po~** Vohmle 2. A1Jgust. 1999, Atlanta, GA. 

### 6. Uitalysl TecJ:nolagy in 

### MHJ;**Pt~** Dfthe 

### Miw1:Jishi SCR. Symposim '87, October 22. 1987. Weisbadeu. FRG. 

### 7.**aondutan~** Louis 

### P. 

# :ur. SCR CompQrtbilily for lireLjungsrrom Atr

### Premu:m:r; p!'Qcccd.ings of the EPRl-DOE-EPA Air Pollution Control 

### Sympoliium- The Mega Symposium, Volume 2, August, 1999, Atlanm, GA. 

### 8. Gutberlet, H., 

### S02 Convc:rston R418 of**DeNO~** 

### Caralysrs

- EffeclS On 

### Downstream P1Qm 

### ComponentsAndRemedialMeasures, Praceedmss of 

### the EPlU-DOB-EPA 

### Alr Pollution Control Symposium

- Tbe Mep Symposium;, Volume 2, Au$USt. 1999,**Atlan~** GA.

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### OETE0007534