### EPA REGION 8PRELIMINARY ANALYSIS OF BURNS & 

### McDONNELL BACT ANALYSIS FORNITROGEN OXIDE AT MILTON R. 

### YOUNG STATION, UNITS 1 AND 2 January 

### 8, 2007



### I. Introduction and Summary ofEPA's 

### Preliminary Analysis·

A. Summary ofEPA's 

### Preliminary Analysis


### After**~view** 

### ofthe October2006 report by 

### Burns & 

### McDOnnell**(B~M).** 

### "NO" Best Available Control Techliology Analysis**~'tody"** forthe Milton R. Young Station**(MRY~),** Units 

### 1 and 

### 2, and after 

### review ofotherpertinent infonnation 

### and studies 

### cited below, EPA's 

### prelitnlnary analysis is that 

### the B&M study lacks sufficient infonnation witbin the 

### BACT analysis. 

### Specifically. dIe 

### study excludes Selecti-y6 Catalytic Reduction (SCR) as a technically feasible control option at step 2 ofthe five-step Top

### Down analysis. While 

### not. presenting 

### NOx control 

### effectiveness Ot catalyst 

### actlvlty"data.. As 

### a result, B&M fails to rank SCR against other control options in terms ofcontrol effectivelless' at step 3, and fails to analyze costs ofSCR versus other conlTol options al stepA. EPA questionS the reaSonS cited by B&M fat 

### tcchnica.1 infeasibilityofSCR. Furthcrmol'c, based 011 a survey ofSCR venda!',. described later in this repOlt, EPA found there are vendors that will offer performance guarantees for this type ofapplication.

. FUlthct**jnrorma~ion** should he requested, to snpportthe analysis with respect:to SCR.

. 

### B. 

### Relevant Langgage 

### trom Consent

### Decree

Under a Federal Consent Decree flIed April 24,2006 in U.S. 

### District

## Court in North Dakota, Minnkota Power Cooperative Inc. and Square Butte Electlio Cooperative ("Defendants") are required, within six months after entry ofthe ConsentDecree, to submit

### to the 

### North Uakota Department ofHealth (NDDH) for review and approval. and to EPA for review, a NOl[ Top-Down BACTAnalysis for each eXisting coal-tired Unit at the MRYS. The Analysis shall include all**informa~on** necessary for NDDH to make a BACT detennination, and an)' additional infonnation requested by EPA'a!)d NDDI-1. 11le Analysis Shall include an evaluation ofSCR, SelectiveNon..catalytic Reduction (SNClt), Over-fire Air (OFA), as well as otherNOll control technologies. 

### (Decree at Paregraph 65.)

NDDH shall review the Analysis and sha.1l devolop 1m BACT detern1inationi whioh shall be pl'eSented to all Parties after consultation with EPA. 1lte determination l:IhaU:be subjeetto the dispute resolution process set forth in Paragraph 147 ofthc 

### Decree. (Decree at Paragraph 66.)

IT. EPA Case-Specific Reyiew ofBurns & McDonnell & EERC Technicalll'easibilitx 

### AnalYBis for Sclcdivc Catalytic Reduction



### A. High-Dust SCR

B&M has eliminated High-Dust SCR a.c: technically infeasible due to issues

### described below. B&M's analysis utilizes areport 

### by the Hnergy 

### &Environmental Research 

### Qelltea' (EERC). EPA's. reSponse on each issue is also described below.EPAPrclirninKfY Amllysis ofB&MNO. aACT Analysis at MRYS lanuary S. 2007 

### Ash Deposition Issae Raised by Burns & 

### McDonnell:

B&M state.o; that

### North Dakota lignite contaiJ.ls avmiable**~d** 

### complexvariety 

### ofinorganic compounds dUl.t conlnDute1:0 

### ash deposition. B&M 

### states that

### this fuel pi'Oduccs ash with severe deposition**cJ.laracteristic~** 

### that are nottypical with 

### otJlercoals.**Wh~n** 

### exposed to 

### the beat 

### ofthe 

### combustion process inside 

### the cyclone bumers. 

### the m4iority of

### the fuel aSh**b~mcs** molten 

### and flows 

### into 

### me boUX>m 

### orthe furoaCe. A 

### significant

### portion oithefuel 

### ash is entraiJied into 

### the flue 

### gas exiting the cyclone barrels at high velocity, where 

### it comes 

### in1D Contact with the. lower

### furnace waterwalls. The 

### portion that is 

### canied with therising flue gas 

### cools and 

### some.is deposited on

### hQatft'ansfer surfaces in the upperf'Urnace HDd boiler

### convection pass. 

### B&M sta:(l:)s thst 

### ash deposition oil heat

### 1ransfersurfaces 

### is a substantial problem 

### for units that fire North Dakota 

### lignite, and thatthe 

### problem is so severe atMilton R. 

### Young thatthe Unit I 

### boilermust 

### be sbut down at**120~day** 

### intervals to allow;

### for cleaning ofash depObits from 

### the boilel' 

### heattransfer sUlfaces. 

### in orderto restore reasonable ftlrnace 

### exit gas velocities and 

### temperatures.
B&M also states that 

### sodium 

### is. a 

### significant contributol' 

### to the "stickiness" 

# ofthe ash produced tj'om 

### firing North Dakota 

### lignite. Sodium content 

### ofthe 

### lignite ush 

### averages approximately 4.4%, and
can nearly 

### double this valuc for some of

### the lignite 

### produced from 

### the Center**min~. Powd~rRiver**  

### Basin (PRE) coal typically 

### averages around 

### 1.5% sodium content. 

### Boilers firing 

### North Dakota lignite 

### typically have a 2.5% higherheat 

### rate (million Btu per kilowatt of

### electric generation) than**~.** 

### typical boiler firing PRB coal, thus requiring more heat input and firiilg 

### more £liel 

### per megawatt

## ofelectricity output B&M 

### states that a 

### cyclone boilerfiring North Dakota ligniw 

### also convcl'ts appl'oximately 50% oftile fuel ash to 

### flyash,compared with 

### a 35% eonvel'Sion rate 

### for· PRB coal-fired cyclone 

### boilers. Overall, B&M states, this 

### results ill 

### an amount Of sodium emitted 

### from a cycione·boiJerfiring North Dakota lignite 

### of**app~x~~t~ly** 

### 7_.3**Ib~~hr** compared with**_<!.~** 

### !bs/MW-hI' for a**P~-fired** 

### cycl0l'le boiler.
B&M further stutes thatthe oatalysts in coal-fired boiler SCRreactors are hlghly 

### susceptible to ash deposition. III a typical conventional highwdust SeR**reactol~** tile 

### flue gas 

### typically passes through two 

### to four layers ofcatalyst mod\lIes. 

### The catalyst modules ha.ve riumerous narrow**p88~ages** to 

### provide intimate Contact between 

### the flue gas. ammonia and oatBlyst, TIle 

### clearance (pitch) in 

### these passages is typically 6-10 milJimeters. A typical 

### catalyst layer is approximately 1 

### to ·1.5metel's deep. '111e catalysts in coal-fired 

### boiler SCRreaotors must

### he oleaned 

### frequently using soot blowers 

### and/or sonic homs. This is 

### true even on units 

### firing fuels thatdo Dot produce a 

### stiol-y 8llh 

### tba.t OOiltribtites to ash deposition. B&M states 

### that ash deposition on the catalyst in 

### a 

### high-dust

# sea application would be 

### severe fur a unit 

### firing. Norlb Dakota lignite.


### Sulfur in the 

### coal is mcidized 

### during excess aircombustion to form sulfur

### dioxide (S02), and 

### a small amount ofsulfur trioxide 

### (S03). Some ofthe ammonia-based 

### reagent iluected**up~trl(am** 

### ofthe SCR reactor 

### will combine with 803 to fot'ln ammonium bisulfate. The 

### catalyst in 

### the SCR 

### reactor will also 

### oxidize a 

### portion ofthe 

### SOlto 

### SOl. Excess unreacted ammonia 

### reagentcarryovert'ammonia slip") from the SCR 

### reactorwill 

### a.lso reactwith these 

### sulfurie acid compounds in a similarfashion. B&M states that the 

### deposition <:hamcwristics 

### for a 

### unit bunling North 

### Dakota lignite 

### will crelfte difficult-to-re.move 

### ash deposits 

### and pluggage 

### ofit 

### conventional 

### high-dust catalyst, 

### and increase 

### the probabilitY thut tilt 

### air pl'cllea.ter downstream and flue gas ductwork 

### will bt pronc to accumulations which could be 

### severe. B&M 

### further states 

### that high-dust SCR 

### perfonnance and cat"dlyslUfe 

### will be severely impacted, and that



### -2-J:.l'APreli!!linnry Analysis of13&M**NO~** BACTAnalysis at MRYS Junulfry 8. 2007 

### it is anticipated that ahigh-dust 

### SCR's catalyst 

### life 

### will be 

### shortened from 3-6 years 

### (typical) to as little as 2-12 months, requiring extended. frequent outages for replacement

. I3&M 

### also**~tes** that hot"$ide air pl·eheat.el·s a.:e,susceptible to fouling.' Tubularair pre heaters 

### originally supplied 

### with all cyclone boilers also**tc~rate** moderate 

### dust loadings. since theirheight and size make them 

### difficultto maintain cleanliness. 

### teak tightness ofthc· air preheater is impor'tant on cyclone.fired boilel'S with .-elatively high forced draftfan discharge (combustion

## .air supply) pressures. 

### A high dust SCI{ installation. says 

### B&M, will be prone 

### to airpreheatertube 

### fouling and pluggage, I'equil'ing; extended, frequent outagesfor**QI~ing..** 

### ... '. 

### EPA AnQlysis of

### the AshDePositiop 

### Issue;

The concern about high amounts ofash material causing blinding ofmacro-pores in 

### the catalyst is real 

### but solvable. Strides in catalyst 

### formulations, catalyst management systems, and re::ently, catalyst 

### regenetat.on processes, have all combinedto lower

### the overdlI 

### cost conlribution 

### ofboth 

### initial and

. replacement catalyst 

### in modem SCR 

### sysrems.

. CorJ'lP-arison ofMKrS/tJ

### SCR Systems Operating onPowdeiRiver**Ba~inSjg.J,.** The B&M BACT 

### analysis contends that 

### the higher ash 

### content ofNol'th Dakota lignite 

### used at 

### MRYS (Center Mine 

### coal) makes the comparison ofSCR feasibility at MRY;S to Powder River Basin (PRB) sub-bituminous coal SCR experience not relevant, 

### Even though the chemical compositions of PRE ash and Center

### Mine coal ash arc very simils!', particularly for the 

### specific constituents ofconcern for catalyst deactivation, 

### the quanlity ofash in the Center Mine coal 

### is more than twice as higb on a 

### per**M~tu** 

### basis, However, for a cyclone**b~i1el',** 

### only about 30-50% ofthe ash ends up as fly ash at full load 

### (less at 

### tower loads) and 

### for a wall 

### on:omer-flrcd pulverized 

### coal boiler 

### (PC boiler), about 80% of

### the ash ends up as 

### fly ash.· Tho l'esiJlt 

### is that SCRcatalyst in al'C boiler PRB**applic~tioo** 

### ;is C)(posed 

### to similar quantities 

### ofthe m<\ior constituents of**conoel'n'<~lkalule** 

### material) as a catalyst would be 

### expo$ed to at MRYS. (FOI' 

### purposes ofthis analysis, we 

### will refer to wall alld cornel' fired boilers as"PC 

### bo!lers," Even though 

### cyclone 

### boilers are sometimes referred to· 

### as PC boilers, for**thi~** docum.ent 

### when thatterm is used, we are not referring to 

### cyclone boilers.) .The B&M analysis**~lso** 

### $Uggests that nlinearcomparison 

### of theoretical total ash or ash constituentrates to SCR 

### catalyst deactivation rates**~an** 

### be made. Although 

### EPA does not believe

### this to 

### be the case and l3&M has 

### notpresented any evidej\cc.9fa quantitative 

### relationship between ash loading and SCR

### catalyst deactivation rates, BPA 

## IrcJs nevertheless examined B&M's arguments 

### related 

### to ash loading.

. . 

### Table 1 below shows 

### a comparison**ofth~** 

### total asll loading for different bOiler designs for No.th Da1<ota lignite, assuming a re:rerence unit ofl.O 

### IbIMMBtu forlignite, 

### lignite will have twice 

### the I\.sh content on aper Btu ba.

..ia, and the conversion.to flyash 

### will be 30

..50% for cyclone boilers and 80% for

. PC boilers, 

## As elm be seen from this 

### compariSon, the 

### theoretical flyash loading for 

### a PC boiler firing. PRB. 

### boiler (O.4IbIMMBtu) will be 

### in the same range as what

### would be expected 

### fora cyclone boiler firing Norlh Dakota lignire**(O..3~O.S** Ib/MMBtu). 

### There are several PC boilers operatIng 

### with SCR to 

### comply with the NOx SIP Call that bUl1l PRB coal

# in PC boilers. As we 

### will. disctlss later, catalyst deactivation due to 

### calcium and other alkaline materials isa «chronic," rathertIl/in "acute" 

### phenomenon.



### -3-**~PA** :I'!'eliminary AnalyRiR oiB&M NOx BACT Analysis at MRYS Janull!Y 8. 2001
Deactivation depends on the 

### tot'ililime and mass 

### exposure, 8l\d 

### the PRB PC 

### l:ioiler data are extremely relevant to evaluating SCR feasibility tOrNorth Dakotalignite.


### TABLEt
Comparison ofAsh 

### Loading fo)" North Dakota Ligllite V!l- 

### Powder RiverBasin Coal


### Total Flyash Loading Total Flyash 

### Total Flyash 

### Total 

### fuel C."yclone 

### 'Boiler at 

### Loadjns .Cyclone Loading PC Coal 

### Type Ash Loading 30% 

### Conversion Boilerat 50% 

### Boller 80% (lblMlVIBtu) (lblMMBtu) Conversion, Conversion 

### (lbIMMBtu) (lb/MMBtu)



# .. North Dakota Lignite 1.0 0.3 

### 0.5 

### 0.8



# -- I**.~-** Powder River Basin 0.5 0.15 

### 0.2-5 0.4 

## -. ;

, . . 

### There at'e 

### a couple 

### ofimportant omissions in the 

### quantitative comparisOll ofsodium ash loading presented in the B&M BACT analysis. Pirst, the B&M quantitative sodium loading analysis pl'esented ill the application does not make a comparison ofNortli DakotaLignite on oycl9ne boilers to PC boilers using PRE coal, which, as discussed above, would have hIgher 

### a"$h loading Uian cyclone boilers buming PRB coal. Furthermore, the sodium loading analysis does not

### take into account en1lre range of alkaline material that would affect ash loading exiting the boiler tiiat is relevantto catalyst plugging. The B&M quantitative analysis appears to f'Ocus on the Jowe.,;ttype**offlyash-emi~ring** boiler design for PRB coal (cyclone) and the alkaline constituent (sodium) that is higher furNorth 

### Dakota lignite compared to PRB coal. As shown in Table I and explained further below, these ash-loading differences are not as pronounced when evaluating all alkaline materials fur PC boilers burning 

## PRB coal. In fdct, Table I shows that, on a Ib/MMBtu basis, totallheoretical tlyash loading at the economizer exitofa cyclone boilel' firing lignite would very similarto that ofa PC boilerfiring PRBcoaL,

Another alkaline constitllent that ha.c; been a concern is calcium, which can react with SO] to plug pores as CaSO... This has been a much-studied problem and the mechanism involves the calciumcontaining proticle getting «cHught" in a maoro-pore ofthe catalyst and sUbSf!quently reacting with S03 in the flue gas. The resulting CaSOd particle is larger in volume than the 

## Cao particle and, in essence, swells to fill the pore. The rdW determining step is the oliginal capture oftha**~lcium-containing** particle; varying concentrations of**S~** and 80] have little effect 

### On the overall ntl"e ofcalcium blinding by the ciogging ofmacro-pores. This, again, points to the relevancy ofongoing, lower sulfttr }'RB SCR operating experience. PRB coal has been shown to have approximately 300/0: mOle calcium in its ash compared to North Dakota. lignite. (Reference: Table4 from the EERC paper. SCR Catalyst Performance in FliJe Oases Derived from Subbituminousand Lignite Coals published in Fuel ProcesSing Technology.) When considering this difference and tll'e fuel to flyash conversion Ia"tCS for cyclone versus PC boilers) the SCR 

### catalyst at a

### futul'e MRYS SCR system would see a catcjum environment similaJ' to a PC boiler PRB coal SCR installation and theref'Ore would have a similarcatalystdeactivation rate.
Other alkaline materials (potassium, sodium and magnesium) deactivate catalysts by deactivating individual reaction sites rather than the blinding by macro-pore plugging 

### that was described for Calcium. The average CenterMine coal ash contentfor these alkaline constituents is about 9%. (Reference:



## -4-HI'A Jlreliminaty Analysis ofB&M**NO~** BACT Analysis atMRYS JtUlllllry 8. 2007 

### November 3D, 2002 EERC Report: Asb Impacts on Sel{ Calalyst 

### Performance. Note that no average. 

### Center Mine 

### lignite ash constituent

### values wel'e given 

### inthe October 2006 BACT;'application, Only 

### wide ranges were given in the October 2006 submittaL These ranges are oflittle**u~** for making meaningful 

### ash loading comparisons.)'This percentage 

### is OOJnewhat 

### lowel' than most PRB cQlilsand within the envelope ofexperience of

### European installations. One ofthe 

### references cited 

### in the 

### Appendix B EERC 

### report, Cichanowicz & 

### Muzio (200I), places the 

### range ofEuropeml SCR

### exPerience with these alkaline constituents at 

### 8% to 

### 15% ofash. ThuS, the c:oal.llsed atMRYS has slmilacpoisoningpotential compared to 

### othercoals 

### in use 

### at SCRwequipped boilers inEurope and the 

### U.s.

In their

### 200 1 SCR survey paper, 

### Cichanowicz and**Mu~o** 

### go further in sayiQg; "Short-tenn explorcitory 

### tests suggestedthe extreme 

### calcium content ofPRB coals promotes**~H** 

### poisoning. However. 

### not all catalyst suppliers share 

### this 

### view. and the 

### first commercial**i~8talIa1ion** with PRB coal has not incurred any 

### noticeable deactivation." In a May 2002 SCRtechnology slUveypaperpresented at DOE's SClVSNCR conference. authors Sanyaltmd Ellison 

### concluded; "Evolved from two genel'ations of design in the late 70s to the early 80s 

### ill Japan and mid 

### 80s 

### ill Germany, 

### 2 X .265 MW ofCamey's 

### l)oint and 375 MW ofMerl'imack are 

### seen to bl;l 

### pioneers 

### ofcoal fired 

### SCR Installations in the USA. Since then, 

### SCR technology has made 

### great strides attaining 

### 93% NOx removal efficiency, 3 ppm ofammonia slip and 0.5% S02 to SO

.. eonversion. SCR 

### units on bolleJ'S with all three firing modes

- 

### cyclone, wall and cornet·, dry 

### as well as wet bottom, have been 

### successfully commissioned and arc if! 

### commercial operation. 

### High dust application 

### ofSCR 

### technology has 

### becn demonstrated oi. 

### units firing**b.mu~illollS** 

### coal with 

### near to 4% sulfur and PRB coal 

### containing over 25% 

### calcium oxide:'

The 

### concern 

### about high amounts ofalkaline matetials in Center

### Mine coal 

### expressed ill B&:,M'g BACT analysis and described in the**Appen.di~** B BERC report is real, 

### though not 

### necessarily unlike 

### operating SCR 

### systems oope 

### boilers burning PRB oo9J. As 

### explained**abov~.** we believe there is value in successful operating experielice realized at current 

### SCR installal.ion at PRB-f!l-ed power 

### plants. The problems cited in the BACT analysis 

### ate being dealtwith at 

### several NO", 

### SIP CaJ1SCR installations 

### today. In addition, the analysis presents no 

### quantitative analytical 

### information derived from the ftring 

### of lignite coal on SCR 

### catalyst deactivation tojustii)r

### tbe fmding 

### that Seltis**infeasil)le~** 

### Engineerillg SoJuti011.Y

## lor. SCRA1!P-1jcations 

### atHigh-Ash Fqcilities 

### Plugging ofSCR 

### catalysts by fly ash

### ar.:c~ulation and 

### bridging

# ofpaSsages in honeycomb 

### catalysts and between plates in plate-type catalysts has been aproblem for**d~signers** 

### a.od catalystvendors since the fil'Sf: 

### coal-fired installations in I:he 

### 197.Qs. The 

### primary response 

### bas**~n** more sootblowing, 

### onJine cleaning equipment, and larger catalyst 

### pitch for honeycomb 

### configurations and·wideI' plate spacing for 

### plate-type 

### contigUlutions. These measures. combined with periodic

### cleaning <lurillg 

### boiler outages have, 

### by-nnd-large, reduced**catllly~1.** 

### plugging to a 

### manageable SCR Jl'0blem.-**Agai~'because** the MRYS 

### units are cyclone fired, the potential for plugging is 

### similarfor these 

### units with their high ash 

### coat compared toPe boilers buming a moderate 

### ash coal. Also, the 

### fact thatthe**~R.ys** 

### units are brought down for planned boilerdeposit cleaning at 120-day 

### intervals provides more opportunity fOl' catalyst, cleaning maintenance than is available at the t.Y.pical power plant.


### Further demonstrating the 

### ability GfSCR designer.! to use 

### existing knowledge and experience 

### with SCR installations for high ash fuels., the Electric 

### Power Research Institute (EPRl) has 

### advised clients



### -5-EPA Prl;liminllr.Y Analysis ofB&M NO. BACT Anltl}'l>is at MRYS January 8, 2001
that based 

### on industly experience on a wide range 

### ofSeR installations overthe year:s5

### SCI{ designs can accommodate fuel types never before used in practice 

### O'n a full scale. In a**S~ptember** 7, 2006lettel' addressed to TXU Power' > EPRI stated, "While experience specificallywith .Texas lignite is limited, this should not prevent suppliers from providing 

### all SCR**~'Ystem** 

### that**m~ts** 

### these. objectives; dealing with a new fuel is 

### similarto 

### the challenge faced by 

### U;S. 

### utilities and their SCR 

### suppliors when tirst 

### installing SCR systems on plants til'ing high sulfur bituminous or PRB·coals. Neither suppliers nor utilities had 

### priorexperience with these fuels, which 

### produce flue gas properties that are**Vel)~** 

### different**fr~rn** those in the Japanese and European plants where SCR has been installed before. Therefore, SCR designel'S had to rely upon their knowledge, engineeringjudgment, and experience 

### with theseol.her coa.ls to design SCR 

### systems suitable for these new applications. While some of the firSt U.S. SCR in$l!ationS 6Xpelienced problems (e.g;. accelerated cat'dlyst; activity decay due to arsenic poisoning**i~** die 

### absence ofsufficient calcium in the 

### coal. and catalyst pluggage due·to 

### large Particle**ash)~** none ofthese problems prevented 

### the systems from achievingtheirNOx goals initially and, eventually, maintaining them over the expected life oftlle catalysts." .'

. 

### OtherAsn 

### Deposition Problema on DO'Wn§h-egTn 

### Components



### In regards to 

### B&M's concerns I'elated to 

### ash deposits on other downstream boiler components, we have already pointed outthat ash loading ofmedium 

### ash coals (PRB) fU'ed in PC boilers would be comparable to the ash loading at the MRYS units. Also, as noted above, the;factthatthe MRYS units are already 

### brought down for planned boilerdeposit cleaning at 

### 12O-d1l.y. intervals would provide additional opportunity to clean these accumulatlons. B&M'sdlscussion ofthese "other" potential accumulation problems does not reach any definitive conclusions related l.O 

### the .technical feasibility ofSCR, so I)PA does not see this as a technical ba.'l·iCJ'to instalJing SCR at the MRYS units. Accounting tor**C'ata'~** & 

### Performance in 

### Top-Down BACT4nalysis

. Finally; the conclusion reached in the B&M BACT analysis thatash**d~posjtion** and catalyst pluggagc 

### will adversely affect SCR J)erformance'(we assume 

### this means cO$ol efficiency) and 

### catalyst life does not necessarily support a 

### conclusion that the technology is 

### technicallY infeasible and that SCR should be eliminated at step 2 ofthe Top-Down BACT analysis. Furtbennore, the B&M analysis presents no quantitative data rela.ted to SCR perfolmarice and catalyst life to.support such a conclusion. 

### Although the catalyst deactivation rdtes ma.y be somewhat higher than the rates eXperienced at eastern bituminous flIed SeR installations, strides in catalystfonnulations and designs. catalyst management systems, and catalyst regeneration**processes~** have all combined to lowerthe**opc~tional** challenges and overdll cost contribution ofbolli initial and replacementcatalyst in modern SCRSystems. However, SCR performance and 

### any real construction and openrtional (;osl.sare factors that

### woulQ**~e** accounted for under thc economic impact stage related to costeffectiveness ofSCR (step 4)**und~** tlIe Top-Down BAC.'T analysis.

I http://www.reliabletcxaspower.com/pdfloglltr_eprt9_1_06.pdf


### -6-EPA Prclinlinarv An.-uvsis ofB&M NOx

. 

# .. BACT Analysis ilt**MRY~**

. JanulIry8. 2007
"Pom:orn Ash" Issue Raised by 

### Burns & Mc:DollneJl:

A secondconsideration in 

### the application ofconventional

### hi~dust SCR.

### teclui910gy on a 

### lignite:. 

### fired**\tni~** 

### says 

### B&M, is the 

### potential 

### ofthe SCRreactOr oatalyst

### pluggage rosultirtg fi'Om carlY over of "popcorn ash" from the boiler, B&M states 

### thatbailers firing·N(nth Dakota· 

### ligon,: have severeproblems 

### with 

### ash deposition onboilersurfaces. North Dakota lignite 

### has 

### abigh 

### propensity', 

### says B&M, to form deposits 

### on the boiler's 

### furnace alld 

### convection pass fireside swfaces. For**Iigniie-f~d** 

### units, the boiler's heat 

### transfer surfaces must be cleaned by sootbJowlng and othel' methods (e.g. water lances) fi'equently to maintain satisfactory boileroperation. Some of the removed deposits released 

### by the cleaning action within the boiler andc:onvection passes form "popcorn ash", whioh will be enlIoained 

### in tbe flue 

### gas. 

### B&M states that 

### carryoverof

### hoiler ash deposits will cOntribute to l)luggage

# afthe "popcorn ash" screen ahead of

### the top layerofSCR 

### reactor catalyst. This ca.n causedistortions in 

### gas distribution ("channeling") through the**~CR** 

### reactor, which 

### will aggravate erosion in the high velocity 

### areas and ineffective perfotmance ofthe catalyst.



### EPA Analysis QUite "Popeorn Ash" Issue:

The "popC01'l1" ash mentioned ill the**~&M** BACT analysis and the 

### Appendix B EERC repOlt ha.s

.surfaced in the past few years as SCR units on lower rank coals; including those burning PRB coals, have
come on line. It is being addressed by increasing sootblowing frequency al'ldj in SQtne cac;es, installing a large mesh screen above the first catalyst

## layer. In addition. the Japanese approach ofusing It hard ceramic "dummy" layerwould also aid in dealing with this material. Catalyst layers are now provided



### . with hardened or erosion-resistant leading edges. Japanese catalystvendors 

### prov19c a"dmnmy" layer of ceramic material with the same cell size 

### (pitch) as tile real catalystlayers beneaih.· The**'~dumJnY"** layer not only pro1.oots the undel'lying oatalystfrom erosion, but

### also permits more 

### VigoIDus sootblowing to deal with the catalystplugging problems. Additionally, new licreen designs now 'being successfully installed and operdted 

### with on-line cleaning to deal with popcorn ash deposition. ,./,

. Temperature Issue raised by Burns & MeDonnelh

A third issue 

### tha.t impacts the 

### feasibility ofinstalling high-dust SCR technology on the NOlth Dakota· 

### lignite-tired 

### units, according to 

### B&M. is catalyst operating 

### tempel·atlJre.**T~e.perfurmance** 

### ofany seR catalyst is highly dependent on tile temperature ofthe flue gas 

### passingthrough the reactor. Typically, a temperdture of600

- 750 degrees F is 

### l'eCJuired to obtain sntisfltctoJ)t 

### QPeration ofan SCR reactor. 

### Opea'ation ofcommonly supplied catalyst Suill\ble for a 

### high-(Illst SCR 

### reactor at temperatures above 750 degrees 

### results in severe and rapid deterioration ofthe cataly!>( and SCR 1'eac1or's NOx emission 

### reduction perfonnam:e. For**bi~uminous** 

### andsub"bituminous coal-fired 

### units, boiler flue gas passing between the economizer outlet and air heater inlet 

### is generally withIn. a temperature range 

### acceptable for conventional SCR catalysts without additional heating orcooling ofthe flow stream.
North Dakota lignite-fired cyclone boilers, including those atMiltol1 R. YOl!ng Station, ha

.....e high temperatures at the economizer's flue gas outlet by 

### design. 13&M 

### lItllle81hatthe 

### hi.QN:st gas temperatures· downstream ofthe convection pass ec:onomizer: sections andupstream ofthe air**h~ter** inlets in Milton R. Young Unit l·s boiler are much hig.ler.than 750 degrees. 'EPA'Prclimitlat'Y Analy;:is ofB&M**NO~** BACfAnalysis III MRYS Ianmuy 8.2001 

### High gas temperatures atthe air 

### heater inlet are required to: produce 

### the higl1 air temperatures (700°F) needed for the pre-combustion lignite drying system. along with primary and secondary 

### combustion air 

### supplied to the cyclones. Such air preheater 

### arrangements and .bilities have been taken into account in the design of the North Dakota lignite-fired cYclone boilers. :B&M states that 

### reducing tbis higb 

### gas temperature 

### to accommodate 

### 'conventional catalysts 

### for**~nventional** high..clust 8CRreactor would result in pre-combusiion air temperatures &It.are tOQ loW to provide satisfactory dJying and ra.pid 

### ignition ofthe 

### high-moisture fuel. B&M further states 

### thatthis will seriously impact reliable combustion, slag formation and tapping in the cyclone burners. 

### Consequently. says B&M. it is not feasible to modify theMilton 

## it Young Unit 

### l's boilerto 

### operatewiththe Jower·cconomi7.er outlet flue gas temperdtm:e.

B&M also 

### states that

### catalysts tora**eonv~)tional** high.:c.ust, hot-side SCR

### ~:ysq,m have not been

.installed nor 

### successfully demonstrated in a full-scale installation 

### ofan operlltingl$olid fuelufired 

### unit that
are designed to continuollsly operate atthe high temperatul'es (above 150**degl'c;:e~** F) ;that exist between the convection 

### pass economizer and air heater on**th~** Milton It. Young 

### Unit j·s boiler.

EPA Analvsis ofthe Tempernture Issue:

The economi:ler exit temperature for MRYS units will be higher than that ofa atypical·' coal-fired utility boller SCR installation, which normally involves an economizer exit temperature ofabout 750°F when the boiler is opemting at full load. When a "typical" unit iii operating at.-educed IQad,.the design problem

### ~lat must be overcome is flue gas that is too cool, perhaps as low as 60Qor. This is typically handled by installing an economizerbypass duel. with a damperthat is gradually 9pened when boiler-load drops below a preset point. The hot bygassed flue gas is mixed with the**rem~il'iing** economizer exit flue gas to maintain the desired 700° to 750 Ftemperdture at the 

### catalyst inlet. Reliable operation ofthese**high-tempeJ'a~lTe** dampers has been**problematj~** aodcareful design is 

### neeessiuy to 

### achieve good mixing ofthe bypass flue gas and the economizer flue gas over- the load l'angc. The**p~tentia1** engineering challenge a.t MRYS 

### may actually present a better situation for high-dust SCR soccess than the ''typical'' designs 

### employed on unitS where the high 

### economizerexittemperatures do not exist.

. At MRYS it would be possible to install a small 

### air preheater ahead 

### of'the 

## S;CR catalyst vessel and ,

. split the primary airflow between**~ir** pl"benters before and aftertho catalyst.,

.By a.djusting the proportion

ofprimary air passing through eaeh air preheater, the temperature of

### flue"gas'entering the 

### catalyst could be maintained at the optimum temperature fOT the parl:icul81' catalyst formulation selected i:mdthc full amount ofheat needed for the Direct-firing Pre-drying Bypass System**wOlll~** be extracted. The costs 

### associated with the two air preheaters would 'be 

### partially offset bythe**eliminat~(m** oCthe airpreheater bypass'and damper

# and by the fact lhat the two 

### ail' pl'eheaters would each be somewhat smallerthall a single 

### preheater. 

### This approaoh also elimimites 

### the problem 

### that some 

### installations**~re** having with inadequate mixing ofeconomizer 

### bypass flue gas. From an operating**standpoin~** the two air pl'eheater approach should be superior to the cu

....ent, "typical" $CR systems.


### Erosion Issue raised 

### by Buns & 

### McDonnell:

Anotherconsideration. according to 

### B&M, on whether hot-side, high-dust SC'R techno]ogycan be

. sllccessf'Ul 

### on

# a North Dakota lignite-fired unit. is the 

### potential for erosion of the 

### seR catalyst .North



### -8-BPAJ'rllJilllinary Aoalysis oi13&M NO. BACT Analysis at MRVS }llIlllllJ)' 8. 2007
Dakota 

### lignite supplied from the Centet· 

### mine has 

### an 

### avel'age fuel 

### ash contentofIPS%, and can 

### have an ash content up to 25.5%. PRB coal 

### fuel ash 

### conl-ent typically 

### averages approximately 5 

### percent. As 

### previously 

### stated by 

### B&M, a cycloneboiler firing 

### North Dakota lignIte**con~erts** 

### a significantly greater amount offlyash than B PRS-fired cyclone boiler. 

### Overall, says**~&M,** this results 

### in a flyash output rate

. from a cyclone boilerfiling North Dalc:ota lignite ofapproximately 83 

### IbsIMWhr compared with 21



### IbsIMW-hrfor aPRB-fired cyclone 

### boiler. 

### High ash contents In.

### the

# flue gas 

### *ea.m; says B&M. can result in physical erosion oftbe catalyst. In**addition~** says·B&M,.effective 

### On-iDle cleaning ofthe 

### highdust catalyst 

### will 

### likely require steam Or

### compressed air 

### sootblowing. 

### B&M states that cleaning 

### cycles of the 

### catalyst will be required 

### muchmore frequently 

### th!lf\ a typical conventional SCR jnstallation due to 

### the ash 

### deposition characteristics 

### oftbeNorth Dakota 

### lignitE) and the expocted buildup and pluggage 

### resulting from the carry over of

### "popc.om ash." F'requent

### sootblowing .ofthe 

### catalyst

### t:u remoVe fouling 

### deposits and ash aCcumulations will contributeto erosion 'and decreased catalyst:life

..There is some European ex.perience with higb ash browri coals thatcatalystmanufacturers 

### wiJl be able 10 

### draw 

### upon. This expel"ience. 

### hciwever, will nQtbe directly applicable to these United States 

### units, SIJ.YS B&.M; oocause 

### of the severe deposition**characterl~1:ics** orthe North Dakota lignite 

### ash compared to brown coal.

EPA AIUtlysjS ofthe Erosion Issue:

.' The high ash content

### oftbe Center Mine coal does, in fact. 

### mean that the a$ l()adings at the economizer exit ofthe MRYS units 

### will be fairly high, but, as discussed ab9Ye, 

### it would 

### be \"Oughly tile
same as typically seen in PC-fired PRB units that are cummtly fitted with SC:R. Sootblowing is common to all coal-fired units and particularly high 

### rates**ofsootblowim~** arc 

### characteristic ofslagaing coals and cyclone firing. SCR vendors have provided a llumberof**~1easures.** to avoid the erosion 

### problems**lh~t** 

### were seen in early Japanese and German installations. First, 

### ca.ta.lyst layers !ire now provided with hardened or erosion-resistWlt leading**edg~s,** including 

### providing 

### "dummt'layer, previously 

### discussed u'nder the POPCOI1l ash section. Finally, today's 

### sea designers are 

### much more sophisticated in design measures that insure a more even aue gas velocity distribution across'the**.cat~yst** layet' surface. Although this is driven by the desire for 

### unifol111 reaction rates across**theca1alys1,~** to achieve 

### the low ammonia slip guarantees 

### reqUired today, it has**th~** additional benefit of**eIim~nating** 

### areas oferosion due to high ash velocity and improper "angle ofattack".

. Energy & EnvirODmental'Reseal'Ch 

### Center Report (APUendix B): :


### As part

### ofthe BACT analysis by 

### B&M, areport authored bythe Bnergy & Environmental Research Center 

### (EERC1 entitledUAsh Impacts on SCR Catalyst

### Perfonnance" was**inclad~d** as Appendix B. The 

### B&M analysis relies on a passage 

### from the 

### HERe t'\:lportM 

### paltofits determinatibn.tliat 

### SCR 

### would be technically infeasible for

### the MRYS 

### units. The passage 

### is as**foll~ws.** 

### «the most 

### s,gnlficant

### problems tllat ptOhibittbe 

### successful operation ofSCR catalysts to lignite coal is the**fonn~tion.** allow-temperature 

### sodium-ca.lcium-magnesium 

### sulfates alld 

### phosphates 

### that will 

### form all the sUrfaces ofcatalysts and the

.carryoverofdeposits that will plug 

### the catalyst openings, resulting in increased pressure dt'Op and decreased efficiency."

. . 

# The BBRe report included in the MRYS BACT analysis relies heavily on pilottesting that was conducted by EERC at

### two PRB-fired plants and one North Dakota 

### lignite-tIred plant. The MRYS BACT analysis also references this test and the accompanying technical paper, "Ash and Mercury



## -9-EPA**1.'relillljn~I'Y** Ano.lY$iS ofB&M**NO~** BACfAnnlysislltMRYS JaJiuary 8. 2007
Behaviour in SCR Catalysts When Firing Subbilumino\ls and Lignite Coals" by the EERC 

### tilat was published in the Febnlaty 200S issue ofFuel Processing Technology magazine. The majority ofB&M's technical argtunents related to technical difficulties of high-dust SCRfor North Dakota lignite appearto have their origin 

### with the results ofthis pilottesting. It is worth noting thai: 

### page 578 ofthe original Februmy 2005 article cited above has nearly identical lancouagc 

### to that used in tlle Appendix B EBRC report, except the conclusions differ on the successful application QfSCR application 

## ofSCR catalysts to lignite coal. '

. "The most It;gniticant problem that 

### limits the suQcessful application of

### SCltcatalysts to lignite coal is 

### tbe fOl'Dlation oflow-temperature 

### sodium-calcium-magnesium sulfates, phosphates. and possibly 

### carbonates that 

### will f01111 on the 

### surfaces of

### eatalystsand the 

### canyover ofdeposits 

### that will plug the catalyst openings. resulting in increased pressure drop and decreased cfficiency [3.11-14]. 'l11e 

### degree of the ash ofthe ashwrelated inipacts on SCR catalyst 

### performance depends upon the 

### composition oftlle coal, the type offiring systems, fhle gas 

### 1emperawl'e, and catalyst design." (Emphasis added)

EPA Analysis oCtIle Energy & Environmental Re.searcII Center 

### lummi <Augend.),: B):

It 

### is interesting**that.~;ERC** characterizedthe technical problems associated SCR application lo lignite-fired boileIS as 

### being "limns" in this technical paper, but say that the problems "prohibit' the successful use ofSCR ill the MRYS BACT analysis AppendixB report. While the former language suggests sucCessful operation ofSCR is 

### possible, tho later language appears to be crafted specifically for addressing technical feasibility in .thc context ofBACr. However, the conclusions reached in the Appendix B report do not address some ofthe engineering solutions previously cited and explained below that arc a.vailable for full-scale SCR applications. Furthermore, EPA Region 8 believes that there may be inherent limitations witb tile pilotstudy (that was the basis for both BERC I'ej>orts)**th~** drdws into question the validity ofdirectly applying those conclusions to tlle range ofpossi\;lIe SCR designs ofa**fl\lI~** scale application at NlRYS. Statements Rom three majol' SCR catalyst mamifactill'ers (including Haldor Topsoe. the catalyst manufacturer involved in 

### the pilot testing for North Dakota lignite) suggest that the Ct'Italyst deposition and plugging problems experienced dW'ing the pilot testing may be exaggerating on a pilot scale .md can be solved in a full-scale design snd application. This is eXPlained in more detail in Section HI ofthis report.
Othet inherent problems associallld with directly applying the results oftlle EBRC pilot testing at Coyote Station on North Dakota lignite include:

. l) The air pulse used 

### to clear deposits during the pilot test is a poor simulation of sootblowing and is much less effective. Sootblowers essentially "blast" the deposits offthe leading edges ofthe catalyst withjets ofsteam or air. TOO test rig used in this project merely blew air into the 

### space above the catalyst face, resulting in a pulse ofhigher velocity. which is much less direct than sdotblOwlng. Most new comml;ll'Cial SCRinstallations aloe a.pplying acoustic horns in lieu ofsootbJowtflg and are found to be vel)' effective.
2) The 6mm pitch catalystused for the pilottesting at Coyote Station is much smaIJerthan currently being specified for coal·fired installations. Vendors 

### are now supplying 9mm, 10mm ur even I Imm pitch catalysts. As discussed earlier. larger catalystpitch is one ofseveral engineering solutions to



### -10-· EPA Prcliminmy Analysis ofB&M NO. BACT Analysis at MRYS .lfUluary 8, 2007
address the problem ofcatalyst plugging for higher ash coal. This current industry**pl'~ctice** makes the EBRC results based 

### on 6 II;Im pitch catalyst essentially obsolete,

. 3) 

### 1'he one meterdepth oftbe catalyst used in 

### tbepilottest is 

### equivalent

## to one layer ofcatalyst in
a commercial**in~tallation.** 

### Conirnerolal systems aimed at high rcmovais have three laYers, each about three feet**thi~** and, at various times 

### in the catdlystIDlIlU\gement'Cycle, incorporate 

### fOllr layers. BERG's test, the11, only 

### simulaled the lOp 

### layer ofa 

### mUltiyIaycr 

### system. Thetop layel' of

### any SCR system always takes the lion's share ofthe abuse from the 

### ash.and the activity degrades at amuch faster rate than the 

### seCOlld and third layel'. The top layer continues to 

### protecttho 

### lowerlayers even when its activity 

### has been severely degraded, This is 

### why the IJISt step in most catalyst maJiagomentsohemes usually involves adding a fburth layer and leaving the badly degraded t9p Ia.yerin place for the second opcl'ating period. 

### BERe's project provides no real insight into the effectiveness and**survivabil~** o.fa second or third layer, 4) The scale oftcstil'lg carded out ill this project is usually associatecl'withobserving catalyst life prospects (01' said another way. the rate ofloss in catalyst activity) rather than physical processes of deposition or plugging, This is because the deactivation mechanisms operdte on a micrOwscalc and can 

### lle accurately simulated at this small seale, butthe plugging and deposition are influenced by larger processes, such as flow imbalance and countemleasures (sootblowing,**homs~** screens, baffles, etc.) and
are not duplicated 

### on the small scale.

For these reasons, EPA Region 8 questions the direct**app1ic~tion** of**th~** results ofthe BERG pilot testing at Coyote Station and the accompanying Appendix B EERG report for**p~os~** ofthe BACT technioal feasibility analysis ofSCR at MRYS, The experience and opinions ofthe SCR supplierthat· participated in the BERC pilottest indicate that the problems encountered 

### du:ritlg the pilottest are not determinate ofwhether 

# seaplugging experienced during the pilottest would be unresol"able by vendors, To the 

### contrary7 statements fi'OIn HaldorTopsoe off-eringtheir SCRcatalystfor installation on lignife..fired boilers indicates that the fulJ.·scaIQ differences and engineering sOlutions lIvaUjililc today provide evidence thatthe BERC pilottesting results should not alone be the deciding consideration when evaluating SeR teclmical feasibility at MRYS.

BUI'ns & Mcnonnellts 

### Conclnsio•• on Technical Feasibility**ofHigh~Dmd** SCR:
B&M notes that EPA's 'NSR

### Manual St"dtes that for atechnology to 

### be feasible it must "available and applicable", The question is whcthel' SCR technology is**~'applicable"** for a

### unitfiring N0I1h Dakota lignite.
B&M further 

### notes that, in accordance with EPA's 

### NSR Manual, atechll0logy 

### is. :Capplicable" if 

### it has been**jns~lIed** 

### on a "similar unit:' Hot-side, high-dust SCR technology has**~en** relrOfitted on 

### coalw fired units 

### featuring cyclone boilers. However, B&M states, thereare.no SCR installations in operation
or planned on units that includecyolone burners tiring 'Nolth Dakota lignite wiLli'severe slagging and f'Ouling tendencies combined with such high boiler economizcr outlet gas temperatures (over 7500P) required for high-moisture fuoJ proolying systems andtubular air

### preheaters.

B&M notes thatthe NSR Manual also states a technology may be detelmined to be not applicable if 4'a. rechnical assessment considering physical, chemical and engineering pt'inciples and/or empilical data



### -11-

### EPA Preliminary Analysis ofB&M NO. BAcrAnalysis at MltYS JIll1llIU'Y 8. 2007 showing tile technology 

### would 110twol'lc. on the 

### emissions unit undcl' review or

### that unsolvable 

### technical difficulties would preclude the successful deployment ofthe technique." In this SCR.tecllnology application. says B&M. it appean that II utility power plant firing North**Da~tlllignlte** would experience extended time delays, 01'**~e** required to devote significant inmrnal resources and engage outside research, followed by extended field trials. to Jearn how to llpply a conventiQlli),1 higb-dust, hot-side SCll technology on a such a fuel source. '


### EPA Anulysils ofthe 

### Burns & 

### McDonnell's ConcluSion:

EPA notes thatthere 

### is considerable experience in the industry to show 

### that**u~e** orseR on North D-dkota lignite is technically feMible, EPA has previously artiCtllated this**b~Jiefm** a number ofnational rnlemakings, including dIe Clean Air Interstate Rule (CAJR). the Best Available Retrofit Technology 

### (BART) GuideJines. and revisions to the New Source Pcrfol'mance Standards (NSPS) for 

### Electric Uti! ity Steam Generating Units (finalized on Febroary 27.2006). These 1'!1lemakings are discussed in more detail in Section III ofthis 

### report,. Furthermore, 

### B&M's assertion that**MR~** would not be considel'ed "similal'" to those PRB facilities that have successfulJy installed SCR is not supported by comparing total alkaline ash loading at MRYS to PRB-fired PC units 

### that convert 80% oftIle 

### ruel"ash to flyash.


### EPA understands from the 

### HERC pilot study at Coyote Station llsing 

### North Dakota lignite, 

### there
was noticeable ash build lip on the catalyst and concerns· with catalyst plugging**d~ril18** the test. While TIERe notes that ash deposition problems were most pronounced .at Coyote Stalion. compared to the two test facilities burning PRB coal, it also states generally that all ofthe coals

# in the pilot shldy "produced ash that had significant accumulations ofash on the 

### catalyst On both macroscopic and In icr08copic levels." Thus. the conclusions ofthe study appear to be that deposition issue,! might be somewhat greater for North 

### Dakota lignite than 

### for PRB coal. Since significantaccumulations ofash on the catalystwas also observed during pilot**~esting** atthose facilities burning PRB**~a1** and thcre 

### arc numerous examples of PRB coal-fired powerplants 

### 8ucccssftJlly operating SCR systems. the qualitative results ofthe pilot testing described by B&M and HERe would not appear to 

### predude successful operation ofSCR on a power plant burning North Dakota lignite. The EERe study does not appear toq4antify the effect thatthe ash 

### acculnulation had on microscopic 

### catalystdeactivation rates oroverall**~lalyst** perfonnance. 

### Absent such information

### that reflects lhe use ofcurrently available 

### full-scale ash loqrling mitigation designs, pilot testing results may not be evidencethat 

### successful implementation ofSCR on North Dakota fired units "is going to be impossible." as stated in the Appendix B 

### EERC report.

As noted abovf? due to the inherent**pi[ot~scale** littJ.itations i.nvolved in this testinS 1 dil'ect applical:ion 

### ofthe effects 

### and/or magnitude 

### ofash deposition during the EERC pilotstudy should notbe used as the primary basis for detennining technical feaSibility ofSCR 

### atMRYS. Tn tIle full-seale installations.**th~se** conoerns al'eaddressed dtninglhe SCRdesign stage, While combustion ofNorth,Dal<otalignite in cyclone boile1'S might present some additional engineering challenges for SCltdesigners. l;hel"e are multiple credible solutions that Minnkota should have evaluated before concluding that SCR is not technically feasible.

The October 1990 EPA 

### drctft New 

### Source Review Manual 

### (NSR Manual) states that a "demonstration oftcchnical infeasibility is based on a technical.nssessmen1 considering physical, chemical m1d engineering principles. and/or empirical data showing that the**tcchl10lo~y** would not work**-12~**EPAPrclimimu)' Analysis ofB&M NO. BACT Analysisll1 MRYS Janullry 8.20crl

on the emissions unit underreview, orthat 

### unresolvable tecbnic!1l difficulties would preclude the· 

### successful**dep~oyment** 

### oftbe technique. Physical 

### modifications needed to 

### resolve technical obstacles do not in and of themselves provide ajustification for eliminating thecontrol technique on the basis of teohnical 

### infcasibilify. However, the cost ofsuch modlfications caR be consideredin estimating cost and ecoilomic impacts, which, 

### in tum. 

### may fonn 

### the basis for elIminating a 

### ootitrolteehnQlogy." (Page 8.20) (Bmphasis added) Based 

### on the aVailable·infonnation, the problems 'Cited by B&M for·appHcation of SCR 

### at MRYS (ash depOSition, "popcorn ash", 

### rompcrawre, and erosion) are:**rc.so~vable** through the engineering solutions discussed above. While such engineering Solutions may be a cost burden to Minnkota, as noted above, step 2 is not the properstage ofthe 

### Top-Down BACT'**3ru~tysis** to account for**th~e** costs. As described in the NSR Manual, "where the resolution ofteclulical difficulties is a matterof 

### coSt, the applicantshould considerthe technolOgy 

### as technically feasible. 

## The economic feasibility of

### a control alternative 

### is reviewed in 

### the economic 

### impacts portion ofihe 

### BA(.'T selection process." (Pages B,19 uB.20) Many ofthe technical feasibility**arguni~nts** presented in the BACT analysis are centered on decreased catalyst life and perfonnance. increased maintenance and outage time, and plant differences

. 

### unique to MRYS that preclude 

### SCR feasibility at MRYS. Consistent with the 

### NSR Manual. 

### lhese
concems are incorrectly incorpol"'dted 

### into the TOp"Down BACT analysis at step 2. and really should 

### be accounted 

### tOr as additional costs per ton ofpollutant removed at step 4 ofthe**a~aly.sis,** 

### Furthennore, the 

### NSR Manual states,**'~:Vendor** 

### guarantees may·providean indication 

### of commercial availability llI1d the technical feasibiHty ofa control technique nnd·could contribute to·a determination afteohnical feasibility orrechnical infectsibility. depending on circuml'tallces. However, EPA does notconsider a vendor guarantee alone to be sufficientjuStification:that a control optiOtl will 

### work. 

### Conversely, lack of

### avendor

### guarantee 

### by itselfdoes not present sufficientjustification that 

### a control option or anemissions limit is technically.infeasible. Generally, decisions about technical feasibility will be 

### based on cbemioal and engineering analyses (as**discu~ed.** above) in conjunction with infOI'luation about vendor 

### guarantees." (page B.20) So; while EPA does notconsider vendor guarantees by themselves to bedetermin8te in making technical fea:sibility decisions, they**an~a** 

### ;contributing tactor in 

### making these decisions. EPA is 

### aware ofthree catalystvendors (Haldor-Topsoe,. Cormetech, and Argillion) who would be 

### willing to prOVide performance guarantees for 

### ligniteuflred boilers applications.

Based on the criteria discussed above, Minnkota and B&D should hav4 fur610r explored both the full-scale engineering solutions used to address the problems cited in their analysis in 

### c.:onjunction 

### with information from SCRlcata1yst vendors to offerperfonnancc guarantees to design and instaU an SeH. unit at MRYS. The BACT analysis fol' MRYS that was submitted relies heavily on the technical problems experienced during the 

### BERe pilot testing at 

### Coyote Station in conjunction 

### with the fact that SCR has not, been installed on a cyclone boilerthat bums North Dakota lignite. We do not believe that this analysis adequately addresses the 

### criteria citw above. 

### As such. 

### it appeal's thatthe case-speCific NOx 

### BACT analysis submitted for Minnkota MRYS is deficient in terms ofimproperly eliminatingSCR from consiqeration at step 2 ·ofthe BACT analysis for technical feasibility.


### B. J

...

### ow-Dost SCR

Burns & McDonnell has eliminated Low-Dust 

### SCR as technically infeasible due to 

### il:>sues described 

### below. EPA's response on each 

### issue is also described below

.



### -13-EPA Preliminary Al1alysis ofB&M NO. BACT**AnHly~is** III MRYS Janual)' 8. 2007 CatalystFouling and Deactivation Issue U.aised by Burns & McDonnell:


### B&M states thatan existing electrostatic precipitfttor(ESP) upstream

# ofa low dust SCR reactorwill still expose the catalystto the acid gas content and fine particulate containing trace metals and the high alkali miner.u content ofthe entrained lignite flyash not removed 

### by the 

### ES}l upstream. Although the total 

### amountof

### flyash 

### carryover into 

### the LD-SCR 

### reactor is greatly reduced**co~pared** with 

### a high-dust design. it is antioipated, 

### says B&M, thatthe low-dust 

### SeR catalyst life 

### wifl still be tmacceptably short. The small particle 

### flyash passing into the reactor will be sltfficient'to calise plLiggage 

### ofthe catalyst

### pores, 

### Says B&M, resulting 

### in deactivlltioo ofthe**oataly~** The tiring oflignim

### coal produceS fine (less dUlIl**5~** pm diameter) flyash 

### particles. 

### which are also least likely to be

### removed bytheexisting particulate colJectioncquipment (e.g. ESP) 

### upstream ofa low-dust SCR- 

### This creates 

### conditions, says B&M, that allow these smaU flyash particles to enter !hepores oIthe catalyst, react

### with SOl in ,the flue 

### gas, and for!n sulfil.tes }vhich bind other a,'\hparticles into a matrix ofsodiulD-, calcium-. and sulfur-rich materials (likely in 

### afonn ofcalc:illm 

### sulfate). B&M states that 

### once such a matrix fonns 

### wltbin the catalyst, it can be extremely tenacious and difficult to remove.B&M notes that one catalyst vendorhas stated it is their 

### "experience that lowudust 

### catalyst is 

### more difficultto clean than that 

### from**higl}.dust~** 

### B&M concludes that low-dust SCR performance and catalyst lif-e could be seven:ly 

### negatively 

### impacted. and that' shortened'lifespans ofthe LD SCR 

### catalyst will require premature, extended, frequent outages fOl' repla-cement.

,**El~AAna1Y8is** uribe CntalvstFuuling and Deactivation Issue:

A 

### few SCR 

### systems installed on**coaJ-fil'C~d boiler~have**  been designed with ,th!3 SCR catalyst installed after the ES1' or baghouse. This approach elil11ina.tes virtually all ofthe poisoning, pluggillg and erosion problems that have been associated with SCR catalyst. (Chris1::nlan MemQ,'2/18l03) For the same reasons noted**ab~ve** under the high-dust SCR

### analysis, the 

### catalystfouling and deactivation'problems may be J'esolvable technical pl'Oblems that do not warrant elimination oflow-dust 

### SeR under step 2 ofthe Top-Do\¥tl BACT analysis. 

### In a recentPSD permittillgaction 

### torthe Desel'et Bonanza II0 MW Waste Coal-FiredCirculating Fluidized Bed 

### project, EPA Region 8 

### did l19trule 

### out-iow-dust SCR based on unresolvable technical feasibility 

### issues Witll catalyst fouling and deactivation. Similarly.,pemlit applications fur three recent Circulating Fluidized Bed projects 

### in Nortb 

### Dakota (MDU WestmOQreland Gascoyne, South**H~rt,** and 

### Gascoyne 500MW) did 'noteliminate low"Dust SCR based 

### on unresolvable technic.al feasibility issues with catalystfouling and deactivation. While there would be 

### inherent costs associated with preheat, other possible 

### physical modifications to the plantto**a~modate** low-dust SCR, and engineering designs to 

### min'mi?G and manage catalyst fouling and deactivation, these factors, consistent 

### with the 

### NSR Manual, should be accounted for when considering the economic 

### impacts ofthe 

### technology.
Site 

### Space CODstraint Issue Ruised bv 

### Burns & 

### Me.Donnell:

The installation ofa low-dustSCR system with flue gas reheat requires a 

### substantial amount 

### of space for 

### installation and 

### operation. A low-dust SCR system will likely use 0. regenerlitive gas-to-gas heat exchanger (reheater) to raise the temperdture ofthe flue 

### gas at

### tile SCR inlet. A**g~s-:to-gas** heat exchanger (GTG HE) will transfer heat from the flue gas at the SCR rea<:tor outlet 10 the flue gas entering the SCR reactor irl orderto rninimi7..e the supplemental SCR energy usage. The GTG HH dictates**lh~** footprint of the cold-side low-dust SCR system. Space is required for the GIG HE and for ductwork 

### in


### -14-EM }>reliminal')' Analysis ofB&:M**NO~** BACT**Anllly~is** III MRYS January 8, 2007
and 

### out of

### the rehellter. Sufficient free space around the 

### reheater and SCR is also 

### required fol' maintenance.

The**~,rea** around Units I and 2 atthe M.R. 

### Young station is ¢)(ttemely congested, says B&M. 

### ill the
areas where 

### low..cJust SCR sylitems must be located. 

### The situation,Is 

### paJ!ioul!U"ly SeVCI'C, says B&M, for 

### Unit No.2. Equipment 

### that. impacts the 

### feasibility ofinsta,llIng alow"dust SCR system on Units 1 and 2 includes 

### the Unit 2 absorbers, 

### Unit 2 flue gas desulfurization (FOD) dewatering equipment, 

### fly ash handling e,quipment,ftlel storage and transfer equipment,**~acks)** failS and 

### ductwork. It would be extremely 

### disruptive

### to the 

### continued 

### economic operation 6f

### both boilers, says B&M. to relocate all the mentioned equipmentto create space for the low-dust SCR systems atthe 

### M.R. Young Station. Stacks. fans and ductwork and 

### the

### Unit 2 FGD 

### system cannotbe 

### readily relocated due to adjacent structures and the need to continue operation while constructing the retrofit installations. 'ryle fuel handling equipment 

### includes a 

### coal 

### storage bam and the main conveyors supplying lignite to the**mlful~** Relocating the coal handling equipment currently occupying spaceneeded 

### tor the low 

### dust SCRsystem.s would be 

### quite difficult, says B&M> given the site configuration. It is conceivable thatthe 

### tiy ash equipment located· 

### west ofUnit 1 could 

### be relocated 

### to provide 

### some oflhe space needed for the low-dust SCR. However. lite availability oftbis space is doubtful, says B&M, since aVoiding the. 

### Jikelihood ofsevcrc SCR catalyst sulfate fouling will require a new Unit 1 FGDsystem to be instlllled. Ifa.newFGDsystem is installed for Unit 1. the FOD system would need to occupy the space that

# can be made available by 

### relocating ash handling equipment. B&M concludes tha.t this space subsequently would not be available for a low-dust SCRsystem.

. .
EPA Analysis ofthe Site Space Constraint lssue:

While 

### the 

### extent ot'thc physical 

### plant modifications 

### necessary to accommodate 

### Iowwdust 

### SCR atthe MRYS is not entirely clear, the above description- does not iildicate thatthe site space constraints at**~RYS** would 

### necessarily preclude

### the possible installation 

### oflow-dust SCR. It does sound like m4ior and costly equipmentrelocatiol1 may 

### be necesSary to provide the space necessary**fOI'low~dl1st** SCR. However, consistent 

### with 

### the.NSR'Manual. «physical 

### modifications needed to resolve technical obstacles 

### do not in 

### alld 

### ofthemselves provide ajustification for 

### eliminating the contro' 

### technique on the basis of technical infeasibility.;' 'lnese 

### Costs should be accounted for whtm estimating the cost and economic impacts of

### low-dust SCR. but should not be 

### used as a basis 

### for eliminating the technolOgy as t.echnically infeasible.

.. .
Bums & McDonnell's Conclusion on Technical Feasibility ofLow-Dust BCR:

Based upon atechnical Msessment tllat looked at the various design and operational issues 

### associated with the installation oflow-dust 8CR technology on aNorth Dakota lignite-fired steam-electric generating unit, B&M concludes that 

### this control option should be**considere~techniea11yinfeasible** for the Milton 

### R. Young Station ·Unit 1's boiler. '

El'A Analysis ofthe BonIS & McDonnell's Conelu..orion:
As explained above, EPA Region 8 believes thatthe inherent challenges with installing and opeJ"ating low-dust SCR atMRYS are resolvable ona technical basis. The fact that a 

### few low"dust SCR applications are currently used in practice indicates that the small-particle catalyst fouling and


### -15-EPA Preliminnry Annlysis ofB&.M**NO~** BACTAnalysis at MRYS 1anuaI)' 8, 2007 

### deactivation problem described would not preclude the use oflow-dust**SClt.~** 

### In &et, EPA Region 8 believes that 

### the dust-loading problems 

### that can be 

### efl'eetively addressedthrough**~ngineeril18** solutions 

### in
a high-dust environment are less problematic than in alow-dw.1: enviromnenti B&D's statement's that "Iow-dust SCR perfOI'lnance 

### and catlllystlife could 

### be severely negatively impacted resulting in premature, extended. frequent "oUlages for replacement" can be minimized 

### by properSCR design and on

### line cleaning. As stated previously, 

### any real costs assooiated 

### witli**~e** 

### construCtion and maintenance required to operate 

### the low-dust SCR should be 

### accounted for underthe 

### economic impacts stage ofthe 

### Top-Down BACT analysis (&'Wp 4). 

### Similarly, physical plant modifications that Would be 

### required to accommodate the low-dust SCR (and auxiliary**~uipment)** 

### shQuld be**consi~red** iylthe 

### economic impact evaluatioll, ratherthan 

### used as evidence of technical infuasibility. '



### III. Additional 

### Information Usefnl to Evalnating Technical Feasibility ofSCR at MRYS

A. EPA 

### Headquarters Believes 

# sea is the CorrectTecbnology for MRYS in Dcvcloning 

### the Clean 

### Air Interstate Rule (CAIR) During the preparation 

### ofthe 

### CAIR**ru)~** 

### EPA developed a scenario 

### tOl' best controls across coalfired units in the United States based on 

### all assessment

### ofbcHler 

### type, fuel t:Y1;le', 

### and existing 

### controls. This assessment recommended that SCRtechnology would be 

### the besttechnology forthe two 

### units at MRYS.


### Several commenters

- 

### Mon(anawDakota Utilities Co. (VI.G-0754); Otter-Tail Power Co. (VI.C0628); LigniteEnergy Council (VI.C-0935); Lloyd. Oosselink, Blevins. Rochelle, Baldwin & ToWnsend, P.C. 

### for Texas Lignite 

### Coalition (VI.C-I037); and Basin 

### Electric Power Cooperative**(VI.B-0690)-~** 

### argued that 

### SCRtechnology 

### is not feasible fOJ' 

### application on lignite-fired boilers. 

### Some oftltese

"oommenters claimed that an SCR 

### pilot test 

### on a slipstream from a boiler"fil'lng ligtlite had shoWn catalyst

plugging and "blinding. 

### One commenteJ' attributed this problem to**~ulfates** 

### ofcaJciumand sodium. which


### arc present in the flue gas stream entering 

### the SeR, as uesultoftifing 

### of

### lignite inthe boiler, One of lhr;:se COmmcmtcrs also claimed"that SCR

### was not feasible for boilers firing $l.lb--bifurilinous.

. 

## . . , 

### In its 

### response at VI.13. of

### the CAIR docket, EPA noted thatthere is considerable**exp~rien¢e** 

### 11'1 the industry to show that use ofseR 

### on sl1b-bitundnous coals and lignite is technioally feasible. SCR is currently in lise 

### on sever-dl subwbituminous coaMired 

### boilers in the U.S. firing 

### PowderRiver Basin 

### coal. 2 

### Regarding the use ofSCR on" boilers firing lignite, EPRl testing 

### ofSeR catalyst in 

### a slipstream at the Martin Lake plant showed acceptable 

### results from Texas Lignite.' Furthermore, the technology suppliel's reportthat SCR bas been successfully used on lignite and brown coal boilers in 

### Europe." from this experience. it 

### can be concluded that SCR 

### can be used on sub-bituminoLls coal and lignite boilers in 

### the

,

It "SCR Lowest NOx Ranking, 3111 Quarter2003," Mcnvaine Website,**www.mcilva;~~ornparty.com.** 

### accessed on December23,2003 (dockctno. OAlt-2003-<lOS3-1940) "



### "Impact; ofTexas l.ignite 

### Coal On SCR 

### CatalystLife and Perfo1ll1ance: Field Datafium TXU'

### s Martin 

### Lake Planl," EPRl Website, www.eprLcom, accessed on December 11,2003 (docketno: OAR-2003-Q053-1944)

4 Email from J. Staudtto S. Khan. Lignite hlstalllltion List, July S, 2004.(dockul nO. OAR-2003-00SJ-1946)

## •

• 

## • .!

EPAPreliminary Analysis ofB&.M NOx BACT Anulysis al MRYS JanUaIJI 8. 2007
U.S. and catalyst supplie1's have indicated thatthey 

### will offer performance guarantees on these applications ill the 

### U.S.s

. . ,. . In the docket information regarding this issue, oDe ofthe SCR catalyst vendor::;, Argillon. provided
a 

### list a

## sea installations atEOUs 

### in Europe that bum lignite orsbnilarrank**~oal.** including:

• Riedersbaeh install81ions 

### in**19~5** 

### and 2001(hard 

### coalllignite)

• Voitsbet'g (lignite)



### • DOl."DlUgen installations in 

### 1994 and 1996 (lignite)


### EPA a.lso noted 

### that the commontcl'$ 

### llave 

### notprovided 

### any details 

### of1116 pilottest that has been mentioned with regards to the plugging lUld blinding

# ora. catalyst'ftom lignite-generated fuel galles. Withoutthis information, this 

### part ofthe comment cannot be addressed properly. The El)A'5 own investigations show that the main reason for this problem was ash build up On the catalyst, witich is a problem commonly experienced in pilot test**f~i1itics,(1** Tn the t\JJI"scale installations, 

### 111is concem is

. addressed during the 

### SCR design stage. The methods used to 

### avoid this problem 

### include duct design to promote ash fallout prior to the SCR. catalyst reactor design to avoid ash buiid

# up. and on-line cleaning methods (sootblowers and sonic horns). '

In addition, the following catalystvendors stated that they could provide .catalysts/SCR for Iigniteu fired boilers:

. HaJdor-Topsoe.**~[c."ln** confinn·that on a general basis Htldol'-Topsoe calland 

### will offer our 

### SeR catalystfor use in lignite--tirod boilers, to be installed either before or aft¢r ash colloot'OI'S.'· Connetech. "Cormetech has no 

### reservations in 

### pl'Oviding perf0l1nance.guarant-ees for application of8CR for NOx reduction all lignite-fired utility boilers." Argilloll."Generally speaking. 

### yes, ArgiJlon 

### would provide perfoml1mce guarantees on 

## seR catalyst on a lignite-tired**boiler~** In fact, we were recentl)' asked Ifwc would do so for a specific '.'_"

__ ._. _. _.

__ .

__**.Q!!U~t** 

### and**w~~ed~.w~J~~!i~e _@~at**  

### our**expcrI~nc~~~~.~.!.1~DE.~.~lign.i!e.~~~_k!,~~!e~~_~ ~~~**  

### .

__.

__._ _ ..

__..

_ . the characteristics ofthe two types 

## orus lignite, ouroverall experience 

### with many fuels,
combined with our in-house flow modeling capability prOVide us with enough information to 

### design camlyst 

### that perfonns as specified."

Email From J. Staudt to S. Khan, Response to CommenL'I. ·IAQR. July 2, 2004 (docket 110. OAR-2003-0053-1945)

6 Email From J. Staudt to S. Khan, 8CR on NO Lignite, August**20~** 2004(doclc.etnd.**OAR~2003.0053.1947)**



### -17-EPA: Preliminnry Analysis ofB&M NO. BACTAnalysis at MRYS January 8, 2007
In ll. memo dated August 20, 2004, .Tim Staudt of

### AndoverTechnology Pat1nel'S 

### to Sikandcl' Khan of EPA CAMD. discussed both the EERC pilot testing results and**~ome** ofthe negative issues raised by B&M and documented how HaldorTopsoe was aWll'e ofthese**iS~es,** but 

### nevertheless felt ·comfortable providing SCR catalyst.

"Re: SCRcatalyst testing 

### on NO Lignite Yesterday I spoke wilh Mr. Flemming Hansen ofHaldorTopsoe 

### l-egal'ding their experience testing Baldo! 

### Topsoe's SCR catalyst on North DakotaLignite. Haldor Topsoe participated in 

### a progratn 

### with the University ofNorth Dakota's 

### BERe and·OtterTail 

### Power. In this program 

### theircatalyst 

### was tested on a pilot

### facility bumil1g lignite coal. Flemming's recollection WdS that the testran sevel'atthousand hours

- possibly around 4,000-6,000 hours. Ca;talyst testing was performed roughly every two thousand hours.

. Flemming's recollection 

### was that sudden 

### fly 

### ash build 

### up on the**~yst** 

### race occurred during the test. The cause ofthis sudden build up" was determined to be accumtilation orash upstream oftIle catalyst mId sudden dropping ofthat 

### accumulated ·ash Ol'\to 

### the CatalYst face. 

### l11is.. he explained. is a problem that frequently occurs in pilot fucilities. but tends to be far less ofa concem for much larger. filii-scale systems. He explained thatthis behavior is also similar

# to that exhibited by PRB 

### coal fly ash, whieh shares some physical characteristics with Lignite 

### fly**~h,**

. As you are aware, SCR system. suppliers perform extensive work

- physical·and computer flow

modeling

- to design the SCR reactorto minimize ash buildUp in fulluscaJe systems. Moreover, cleaning**d~vices** are always installed to 

### clean the catalyst on-line. So there are engineering solutions to address 

### fly ash build \Jp. And, f1S experienced with SCR-equipped boilers that fire PRB coal, SCR systems call be designed to acoommodatethis 

### fly-ash behavior while providing reliable operation in 'elecnic utility plants,

.
Recall thatHaldor Topsoe provided a statement saying thatthey would offer their SCR catalyst for installation on Lignite-fired boilers either before or after particle 

### collection. l1tis statement was provided on JuJy 2, 2004, after their plllticipation·in the pilot test on l·ignite-fired coal. So, this statement was made, no doubt, with knowledge ofthis program."

.. .
B. SCR Technology is**l~rcSumptivc** BART for 

### Cyclone Boilers

# in EPA's BART Guidelines
EPA made a specific and informed decision in its BART Guidelin.es regarding oyclone-fired utility boilers. Forall otherboilertypes, some fonll ofcombustion control was deemed to be the presumptive 

### level ofcontrol. However, for cyclone units burning any

### type. ofcoal (bituminous, subbiturninotls, or lignite), presumptive BART is 

### SCR. SCR was selected becausethe technology is· 

### feasihle and costeffective, especially considering the high baseline flue gas NOX 

### concentrations**(e.g.~** 0.8 IbIMMBtu). The spreadsheetthat was used to tabulate BART source control costs for the BART rule showed low SCR 

### costs for 

### MRYS 

### (about $550/0011),



### -18-EPAPteliminary Analysis ofB&M NOx BACT Analysis at MRYS

. January 8. 2007


### C. February 

### 27. 20061i"malRevisioDs tg 

### 40

# emPart· 

## 60, SubAAttDa,

# New Source !JerformaD'le'

### Stnn,danls fur

### Eledrit 

### Utility Steam

### Generating ll!ifs SetFinal 

### NOx l.imit

### na~ed 

### ·011 TeclJnical Feasibility of

# seu for

### ~:iitpyFjre~**.uDits~** In its 

### response to public comments on the 

### February 28,2005 dra1fNSPS, Subpart Da. proposal, EPA rejected comments received on NCh.

### con~~requiremcnts 

### futJignito-:fll-ect units: Speoifically, EPA 

### took the 

### same position as 

### it did in the 

### CAlRaitd BARTndes. 

### rejtlcting commenters' 

### concerns that SCR would not 

### be feasible for 

### lignite units. No legal 

### challengeS were made to the finall'lJle 

### regarding EPA's 

### response to the lignite concerns. While 

### the 

### revisedNSP8,**~bpart** 

### Da wouJdappJY**o~y** to 

### new lmits. 

### it is fulther evidence that EPA**t~Jmical** experts 

### believe that 

### SCRean':successfOUy be: 

### applied to 

### lignite facilities. The B&M BAct. 

### analysis essentially makes the same 

### teChnicat**arf;ume~'t$.** 

### that EIJA l'ejected in this rule package. " , 

### D. 8m and Catalvst Vendor Information


### As noted above, the following 

### catalyst vendors 

### were comfortable .providing:c;atalys(s/SCR

### for lignite-fired boilers:

. . .

• Haldor..:.Topsoo

• Connetech



### • A.rgilloll
In addition, the above-cited memo dated August

# 20, 2004, 

### Jim Staudt ofAndover

### Technology Partners 

### to Sikander Khan 

### ofEPA**CA~,** 

### discussed both the 

### EERC pilottesting results and some 

### ofthe negative issues l'8.ised by B&M 

### and documented how Haldor

### TQpsoe was**lI.wa:~** 

### ofthese issues, but

.nevertheless**~Jt** 

### comfortable providing SCR catalyst.
EPA**R~gion** 

### 8 also contacted 

### the Instittne ofClean Air 

### Companies website fo:obtain the following list of21 companles offering "SqR Systems, 

### Equipment, Supplies 

### and 

### Services;"'



### • ALSTOM POWER



## • Argillon LLC



## • Babcock & Wilcox



## , Babcock Power Inc.



## • BASF 

### ,



### •**Conn~toch,** lne.


## • Coming Incotporated



### • CRl Cattlyst 

### Company , CSM**Worldwi~** Inc. 

### .. 

## •

• EpconIndustriaJ 

### Systems. N.V.


## • Fuel Tech. Inc.

, 

# . GB 

### Energy Services



## • Haldol' Topsoe. Inc.



### • Hamon Research-Cottrell, Inc.



## -19-.1
":, EP:A,Prclhriinary Analysis ofB&M**NO~** BACT Analy$ill at MRYS .1(1iJUllry 8. 2007

'" Hitachi Power 

### Systems America.. ·Ud

.. 

### '" Hitz America Inc; ,
III Johnson Matthe}! Stg,tionaiy Source Emissions Coritrol

'" Millennium Chemicals

. ':". '.,:

..

• Mitsubishi Power Systems AmenSf¥, hie.

• SClt-'fech

'" Wheelabrator Air Pollution Control; Inc ';i

.' 

# . EPA Region 

## ghas visited 

### mostotthe**vendol'S~** 

## websites ll'O,d**rourid"~any** 

# vendors with experience that would be 

### gennane to the MRYS Situation, (Others are not**vendo~** for hirge power plants.) 

### 'rhe 

### experience ofthese companies should be used to supplementthe endorsement by three ofthe SCR catalyst vendors used by EPA in the backgrou,nd 

### research fOl' the CAIR, BART, and NSPS rules. We believe 

### it 

### would be prudent for 

### Minnkota to**ob~in** ·information**mi~** 

### proposa.!sfrom more than one vendor and involve the NDDH and EPA in tJleir**findill~;s** .



### .,

:. i

"'

. ,



### -20-