### Via Federal Express & 

### Electronic Mail 

## OCT 172008 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGIONS 1595 Wynkoop Street DENVER, CO 80202-1129 Phone 800-227-8917 http://www.epa.gov/region08



### Ref: 8ENF-L

Mr. Terry O'Clair Director, Air Quality Division North Dakota Department ofHealth 918 E. Divide Avenue Bismarck, ND 58501-1947
Re: Transmittal ofEPA'B Response to Minnkota's Letter on Public Comments Received for the North Dakota Department ofHealth's Preliminary NOxBACT Determination for Milton R. Young Station
Dear Mr. O'Clair:
This letter responds to a letter from Minnkota Power Cooperative, IncorPorated (Minnkota) addressed to the North Dakota Department ofPublic Health (NDDH) dated September 22,2008. Minnkota's letter and enclosure were, in part, a response to comments submitted by the United States Environmental Protection Agency's ("EPA") to NDDH on the Preliminary Best Available Control Technology (BACT) Determination for Nitrogen Oxides (NOx) for Milton R. Young Station (MRYS), Units 1 and 21 

### (the NDDH preliminary BACT determination). EPA received an electronic versiol! ofMinnkota's letter on September 26,2008. Although Minnkota submitted its comments nearly two months after the public commentperiod closed, EPA understands that NDDH intends to include Minnkota's response in the administrative record for the final BACT determination.
EPA understands thatNDDH needs to close the record so that a final BACT determination can be made, but some portions ofMinnkota's letter need to be clarified and corrected. To assist

. NDDH in developing an accurate administrative record for the final BACT determination and as

part ofthe EPA-NDDH consultation process described inparagraph 66 ofthe Consent Decree (Civil Action No.1 :06-CV-034, United States ofAmerica and State ofNorth Dakota v. Minnkota Power Cooperative, Inc. and Square Butte Electric Cooperative),2 EPA is submitting

1 PerJuly 8, 2008 letter from NDDH to EPA, the public commentperiod closed on August 1,2008. 2 "After consultation with EPA, NDDH shall provide to the Parties its BACT Determination for NOx emissions from each existing coal-fired Unit at the Milton R. Yoimg Station."EPA Response to Minnkota's September 22, 2008 Letter 

### this response and additional information. I respectfully request that this information be included in the administrative record for NDDH's final BACT determination.
EPA providedNDDH significant evidence that selective catalytic reduction (SCR) as a control option is technically feasible, particularly in a tail-end configuration. Minnkota and its contractors failed to address this point orprovide any additional data or facts substantiating the claimthat SCR is technically infeasible. In fact, in Appendix A to Minnkota's letter, Burns & McDonnell's subcontractor, Mr. Volker Rummenhohl ofTackticks LLC, never states that SCR would be technically infeasible at MRYS. In addition, Minnkota's dismissal ofthe statements made by catalyst vendors and SCR system suppliers provided by EPA regarding performance guarantees for tail-end SCR is tenuous and inconsistent with EPA's "Top-Down" BACT procedure, as outlined under Chapter B ofthe "New Source Review Workshop Manual--- Prevention ofSignificant Deterioration and Nonattainment Area Permitting," (Draft October 1990), (EPA's NSR Manual).3 Vendorresponses and actual operating examples4 

### related to tailend SCRpresented by EPA strongly indicate that·SCR is a technically feasible option. Therefore, EPA continues to beli'eve that the NDDH's preliminary BACT determination of technical infeasibility for SCR is not supported by the record.
Enclosed is a detailed response, prepared by Mr. Hartenstein, Principal and Co-owner of E&EC, an energy and environmental consulting firm, correcting inaccurate information and refuting the conclusions submitted by Minnkota. Thank you for considering the information and clarifications to the administrative record enclosed herein in the final NDDH BACT determination. Ifyou would like to discuss any ofthese matters, please call Cynthia Reynolds at (303) 312-62006 or BrendaMorris at (303) 312-6891. Sincerely,

# ~T~ 

# r Andrew M. Gaydosh Assistant Regional Administrator Office ofEnforcement, Compliance and

Environmental Justice
Enclosures: Hartenstein Report & References (2 copies on cd)

3 "Vendor guarantees may provide an indication ofcommercial availability and technical feasibility ofa control technique and could contribute to a determination oftechnical feasibility ortechnical infeasibility, depending on the circumstances." (see page B.20) 4 According to EPA's NSRManual, available control options include "technologies in application outside the United States to the extent that the technologies have been successfully demonstrated in practice on full scale operations." (see page B.11-12) 

### -2-

### cc: David Glatt, NDDH (w/o Enclosure), Dean Haas, NDDH (w/o Enclosure), Jerry MacLaughlin, USDOJ (w/o Enclosure), JeffKodish, OECA, (w/o Enclosure), Ron Rutherford, EPA (w/o Enclosure), Cindy Reynolds, EPA (w/o Enclosure) BrendaMorris, EPA Hans Buenning, EPA



### -3- EPA Response to Minnkota's September 22, 2008 Letter

### Remarks to the "Comments and Responses to NDHH Regarding U.S. EPA Region' 8's July 31,2008 Comments and Plains Justice July 30, 2008 Comments on NDHH

Preliminary NOx BACT Determination for Milton R. Young Station (MRYS)" dated September 22, 2008

by Hans Hartenstein

ON BEHALF OF THE

UNITED STATES DEPARTMENT OF JUSTICE

October 2008

page 1 of24General Remarks
This report was prepared afterreviewing the "Comments and Responses to NDHH Regarding U.S. EPA Region 8's July 31, 2008 Comments and Plains Justice July 30, 2008 Comments on NDHH Preliminary NOx BACT Determination for Milton R. Young Station (MRYS)" prepared by Bums & McDonnell dated September 22,2008 (referred to hereafter as the "Document").
Even though many detailed comments, corrections, rectifications, clarifications and remarks are being provided in this report, I would like to offer a few general comments. The Document does not provide any new, previously unknown facts or offer any new technical arguments. Again, the majority ofthe Document is directed at HDSCR and still doesn't adequately substantiate the claim why TESCR is considered technically infeasible. While the Document discusses the various types ofdeactivation mechanisms in minute scientific detail, which were never disputed per se, it fails to address the rate at which this catalyst deactivation occurs in a TESCR system. This however is the most critical issue and no data is provided to answer this fundamental question.
Bums & McDonnell, who claims extensive SCR experience and expertise, retained an additional SCR consultant (Tackticks LLC) in order to provide technical comments concerning the SCR technology. Unfortunately, Bums & McDonnell's SCR consultant only provided one reference for the numerous claims and statements made in Appendix A ofthe Document. Interestingly enough, Bums & McDonnell's SCR consultant

- contrary to Bums & McDonnell

- did not arrive at the same conclusion, namely that SCR is technically infeasible for MRYS, but correctly concluded that "the possible application ofany SCR technology at Milton R. Young is not standard, due to special considerations pertaining to lignite, boiler operating temperatures, flue gas reheating, among others." I agree with the statement that this SCR application is not "standard" in the sense that it exactly replicates the standard type ofHDSCR used up to now in

.the U.S. However, this by no means supports the Document's ultimate claim that SCR is technically infeasible for MRYS as proven by the wide varieties ofSCR applications and extensive experience worldwide.

Specific Comments to the Document's Section "Corrections, Clarifications and Omissions ofHartenstein and EPA Comments": My comments to the statements made in the Document are offered in the following, each of which is preceded by the statements presented in the Document for easier reference.
i.**Hat1:eill~leifl** 

### Ift'lPHe:s lhal**li~lt-e~ffroo** 

### b<rHers ar-e .S.igilHi'Clmdy 

### repre.senttd atfM)ug 

### the 30,000 

### MW of

### SCR**syst~** 

### ijlsrnlled ttl 

### EI.1fO<PC. This is 

### misleOOingaod substlm!tiIldJ)'looorrect. VCJ)' 

### few ofth-emart()' SeRs 

### tetrofhin Eun;)pe we.J'¢ 

### instnUedon**li~~ite.cfired** 

### utiHty 

### 00i1er:s-. TlJIcktk;k:5;**b~** 

### advisedlbatlo 

### dlJe best**of~helr** 

### bowledg,:e. they 

### area\Vare (}f

### SCR

### being**o:d~inaUy** installed

### at0111y ('V;i() 

### plftll'tS\, rmdneitberofthese

### ptams is OiJ:J<ei'aitlonQl t'Qcday..

page 2 of241. My report is not intended to imply that "lignite-fired boilers are significantly represented among the 30,000 or so MW ofSCR systems installed in Europe." The fact ofthe matter is that Europe has over 62,00o.MW ofSCRs installed, ofwhich approximately 35,000 MWare in Germany. Again about 40% ofthese 35,000 MW are TESCRs. At least five HDSCRs were installed on lignite fired units, namely: Bayer Dormagen Unit 7, E.ON SchwandorfUnits B, C and D and Voitsberg 3. All units were operated for between 10 and 16 years and four ofthem were decommissioned in the early 2000s for purely economic reasons resulting from deregulation ofthe German utility market1

. Voitsberg 3 was temporarily shut down in 2006 as the supplying lignite mine ran out ofcoal. It is currently being converted to a blend ofbituminous coal and biomass and is expected to start up again in the near future with the same HDSCR2. 2, The**EPAQlg'U~ ~t**  NODF)':$:**~limtna.ry** 

### BACTDetetmj:nQtaoo!be$**ootp(oper1ycom~** the

### emiS'$:iJl.):n!)ft'(lit'n (Jtbel'**ool!d~f.iJi'ed boUusj,\lhhhi~**  fuel 

### S{.\diuftl**OI,):nt~t** to other boilers

### that**$u~sfu:ny opeJ:'~le**  

### SCEsllriu:g Powder Rh''er**B~in** (PIRB)**(;oalwid~ hl~h**  

### dustSCEslnthe 

### Unit,ed**Staih~$** 

### 'f!WJd are**'C(;rt'fli~~to~he** YOllfi8 

### Smdonb<rJleJ:\S f{)f**~eir** 

### dlyash. alkali 

### contenti).. The EPA**i~Of~i the:Departn}~f$** **suppor~1l$J;** 

### demiled**hdbit'1i't~i(l1l1** 

### hy EERCdmt

### e.'q:l4UfiS "'iihy**SCR$~e** 

### iiot**~ble** 

### to 

### ¢QJel"aIDethehigh$' 

### levels of**~kaSi :~cie$** **O(~tta:ined iilfi~.e**  

### taS suoh**,~') eXhl1l;u~tedri:'O'Jtlthe**  

### MRYS' 

### il;iQller$.**~,** 

### CQ.tnpared t() 

### the PRB 'C'll,l,J,1i1 

### 'llredbt)il,er$"

2. EERC's outline as to "why SCRs are not able to tolerate the higher levels ofalkali species contained in flue gas such as exhausted from MRYS boilers" is based on the assumption that HDSCR is used where significantly more fly ash gets into contact with the catalyst than in a TESCR installation. No data substantiating thecHtirrts for catalyst deactivation in a TESCR application, where virtually no residual fly ash is present, is presented by the Department. 

### ), 111 ftdtUI1:i;fJtl, the

### EPA 

### MdHartenstein

### did 

### not prQvide

### any $il;lhstanthtl**techni~l** 

### infurrnatio:n that**ooi'not1st1':at-eslh~lt** 

### ,efl'eet&ve $ll,lllilltioUSKi< prevent (if remove

### j:Kl'rc**t')~u~sa;geand ~;!hlldi~t~**  

### 'of 

### SCR**'~IU'JllY'$t** 

### fB'{;m sodhutl"-**~nd p(litoo~ium**  

### ..**rid~** 

### speciespr,esent

### in**the-flue:b~ $tf~n'~**  

### exhaushed t'foma

### N>\uth**Dakt)t~ Il~'flit¢:"-firtXl**  

### cydone**ooileJ~whethelf** h'if.!ml;edttl 

### a**~)i1i"'''el~ti!(linl!d** 

### hot-.side Qf

### e-Old"'siide aj:tjpHc.;alioo OO\I,<nstreamof

### a'wetserubber, bave been**devek~~d** 

### b'jlc;niUystvendOfi;;,

1 Co-firing ofbiomass

- evaluation offuel procurement and handling in selected existing plants and exchange of infonnation (COFIRING)

- Part 2, Kraftwerk Schwandorf, Gennany, Alteme ABV-NET V, Ruth Brokeland, C.A.R.M.E.N.

l**http://':.y_~.wirtschaft§..Qjatt.,!!!home/oesterreich/untemehrnen/steiemlark/3l7197/index.d..Q**

page 

### 3. of243. My report is not directed towards demonstrating effective solutions to prevent pore pluggage and blinding ofHDSCR catalyst from sodium- and potassium-rich species present in the flue gas stream exhausted from North Dakota lignite-fired cyclone boilers. The only data presented by the Department showing such pore pluggage was obtained during the Coyote Pilot Testing. This, however, was an HDSCR arrangement and not a TESCR arrangement, which means that the data does neither properly represent the types ofdeactivation mechanisms nor the rate ofcatalyst deactivation that can be expected in a TESCR, where virtually no residual fly ash is presentanymore. Therefore, the amount of particles available for pore pluggage and the formation ofa surface blinding layer as well as the amount ofsodium- and potassium rich ash particles is greatly reduced, which in return greatly reduces the catalyst's deactivation rate. The Document misses the point that only the rate ofcatalyst deactivation remains in question rather than the undisputed fact that among other physical and chemical deactivation mechanisms pore pluggage and surface blinding can cause catalyst deactivation.
TESCRs have a proven track record ofvery little to no pore pluggage and/or surface blinding occurring. Initially, isolated events ofsilicon fluoride (SiF4) blinding in bituminous coal-fired units were reported but only persisted for a very short period of timed. Several mitigation methods were quickly developed and SiF4 blinding has not been an issue for more than a decade in TESCRs. Furthermore, extensive experience has been gathered with the removal ofpore pluggage and blinding ofSCR catalyst from sodiumand potassium rich species by means ofin-situ, on-site as well as off-site regeneration of HDSCR catalyst exposed to flue gases from i.e. 100% biomass combustion containing high quantities ofsodium- and potassium-rich species. Simple catalyst washing either insitu or on site is an effective method to quickly remove alkali poisoning from the catalyst. This has been demonstrated for more than a decade and is currently regularly used for units with HDSCRs burning biomass in Europe (i.e. Elsam's Avedoere Unit 2)1, l,§,Z.

1 Personal discussion with plant personnel at Evonik's Herne, LUnen, Marl, Walsum and Voerde Generating Stations

.1 Cleaner Fossil Fuel For Sustainable Development. Co-Firing Coal and Biomass, a presentation by Henrik Noppenau, Elsam (Energie E2 until 07/0112006 ), Denmark

2 Washing Your Own Catalyst, a presentation Nathan White, HaldorTopsoe, 2007 NOx Round Table, Cincinnati, Ohio

2 Considerations for Catalyst Deactivation and Regeneration When Firing Biomass, Dr. Greg Holscher, CERAM and Mark Ehrnschwender, Evonik Energy Services, 2008 NOx Round Table, Richmond, Virginia

1 Mobile Katalysatorregeneration in der praktischen Bewahrung, Dr. Herwig Maier et. al. EnBW Kraftwerke AG, VGB Konferenz Chemie im Kraftwerk, 2006

page 4 of24

### 4. llartenSlern dh;l

### tlot**demonSh~t¢** 

### he

### had an**I,mdersrnnd~ng:ofCent¢J' Hgtl~rechal'~rerls[h~s** **~nd** 

### 'ii'artabmty**~$S'ue$.** 

### Specifi<:afly>

### hecUd**flOt~ndersl4lfld** 

### how soluble**~l<lhim** 

### is used**t~)** 

### .oofme 

### theaboodlmce

### of**(yJ:'~fiic2n:y** 

### ,QS$()dnted**~lum** 

### iuHgnite and

### hO\v**~dhlm** 

### \\>ill**v~** 

### because (if

### the

### abUilldance (yf

### other IOfil.'iiilg**C~fi1j)t~fitS in·~**  

### {)oa1. Tbe**;abund~)ce** 

### ofsoditun**~nd** 

### other

### ashfurming: oompo.ttents**.~. dt·.Il~iatic;aJiy** **~ndijfiiqucly ~n**  N()rm 

### Dakota(fOt1 UI1JOU

### region} lignhe co$and resmt**tnQperari~l e~IIet'l.ge$.**  HarteJi,s,reiti 

### does 110l 

### llil:\derstandthe**differ.ene~** 

### betvi'eet'i f()rtUrlt()fi lignite 

### and Texas 

### lUgn:ite. HelildiCllte$ 

### that the**lti$t~la:tJoo$** 

### ofSeR

### on PowderRiverB$$ifi (PRB}

### subbiturrunous ,coal MdtestingOifl**T~$lignlte** 

### tnd1<:ate**f~bilhy** tor SCR Q-U ND lignite eVeJi 

### though the**lcve~$·** 

### ofsodiumin 

### typkal PRB**(:o~l** 

### ¥lIJJd Texl!Is 

### Ugcites lltre V{}ty 

### low (0.7 to 

### 15% 

### NatO:' as CQI'tIpl'U'edto

### 4.4 

### % NazOfor Center

### lignite. The: ,u:mourat f{)rm i..)(

### oltalls:p.edes in tbe0011d**~Otlg.** 

### wid1

. oombusliOfi**pr\l'O~** 

### it'ifh.letLOCefhelfability to 

### be

### enrichedbi

### d:veaCifOooi ilnd f'lrie**p~rricle ft'~cti:()n**  

### of.he: ·f1.)1 

### ash, Thes4:ze:

### 4IfldCQfftpositioll 

### of

### the**pm'tjck~** 

### ,u:lQlllg:whh velocity**d¢term~nes-** 

### theit 

### abHity to 

### petLetrote- $1{1**~"iL)sit** 

### on SCRcat!'tlyst**P~$$#gts:~nd** ill**rlO~** 

### Md cause**P~I,liS!?:ing> bljfidil1g.~ld**  Po1SQIflJf.I;g.
4. The Document seems to erroneously assume that the purpose ofmy report was to demonstrate my understanding ofCenter lignite characteristics and variability issues. Again, the arguments presented are solely directedtowards HDSCR. Organically associated sodium and potassium compounds are also present in high quantities in flue gases from biomass combustion in Europe either in combination with coal or without. HDSCRs have been successfully applied for such flue gases from boilers firing ufo to 100% biomass (i.e. Elsam's Avedoere Unit**2~** 2, Wienstrom's Simmering Unit**1~.** My report is directed towards the SCRtechnology and its technical applicability. No data substantiating the claims for catalyst deactivation in a TESCR application, where virtually no residual fly ash is present, is presented in the Document.

.!! CleanerFossil Fuel For Sustainable Development. Co-Firing Coal and Biomass, a presentation by Henrik Noppenau, Elsam (Energie E2 until 07/0112006), Denmark

2 Washing Your Own Catalyst, a presentation Nathan White, HaldorTopsoe, 2007 NOx Round Table, Cincinnati, Ohio

lQ Considerations for Catalyst Deactivation and Regeneration When Firing Biomass, Dr. Greg Holscher, CERAM and Mark Ehmschwender, Evonik Energy Services, 2008 NOx Round Table, Richmond, Virginia

page 5 of24

### 5,**H~t.ensteln** 

### tiMl1otaddre$s the issue

### ofehepat1it1ooing of

### ash--furmmg species bet\\'een the :s4a.gandfly 

### ash

### oomponents in**<::yclone~f1red** 

### Sj'stems .nat

### resule

# man eJlrid'unentof$Odium .andothcrf'lart\e':\?Qlattli2ed 

### speciesiU 

### the fh.iegas. These**fltUne~v{)l~tUized** 

### spe.cics wIH 

### OOl1denseho:ttlO<geneously 

### to

### s>roduveabundant sodium andpota,

....**~lum~rieh** 

### aerosols because ()f

### the h't'I.I/¢.f

### level {)f

### entrained soHdash

### partidesin**tycl~** 

### combustlc,n·<Ieri"'e<lfluegases ,'eh'ttive t{> 

### pulvcri2e'.d

### coal Ct)mbm:tto;tlderivedflue**~_** 5. The purpose ofmy report was not to discuss the partitioning ofash-forming species between the slag and fly ash components in cyclone-fired systems that resultin an enrichment ofsodium and other flame-volatilized species in the flue gas. Again the arguments presented are solely directed towards HDSCR. No data substantiating the claims for catalyst in a TESCRapplication is presented. Since virtually no residual fly ash remains in the flue gas downstream ofan ESP and wet scrubber, these issues are of little ifany relevance for the deactivation ofTESCR catalystby fly ash particle-bound compounds. 

### 6. 

### Bartenstcindid**~(}t** 

### address the l'CtriTh1tk1ll1 (lif

### aero$Ols ,and how that CM impae:t 

### SeeR**:1:ted(m'i'~al1'Ce,** Tine k"ey**is~me** 

### tbr**hi~l** sodhll't'llf'Oft**Un~{)n** 

### {North lXiko'ta a**i~nite)** coots 

### fired 

### in**(.,j.rcJ()11:e~f:ifed** 

### ihoilet'S ,is the abm'idIDICeof**~kaH-flch** 11erOSt)lsiifh lil:e flue gas thM CM peilleltlilte JtlilO ;dle

### pores ()f SCR**c~!udyst** 

### (4ltlsingblinding**~lnd pOl$onin~,**  This 

### is atl**):\J.s~e** for

### high dUS;l**~nd** 

### low**d~t** 

### !**~~H·eJjrd** 

### SCR**~pp'Hc~ttil)n:"** 

### He

### app¢:llif$ te

### notbefnmtHa,rl.vhh th,e 

### diffhsaon 

### meclmnism ottrat1:Si,fXtrt

### QfIiIe:JXlISt)ls 

### doop tti,lO the 

### OCReatl!dySotsthat CanCftltse

### p<>ts<tl'tht,gat'id**~Jlu.&;8ln~,P1i!l:rtenl;;tel,n** 2iPt",ears 

### tet**OOflf\ilSie~be** 

### importance of**(;atlilys~** 

### pitch 

### relative !-o f>;)fe 

### plu2"ghi! 

### and bHildJitlg. 

### I"Ie

### incorrectly**s~~tsth.at** 

### C1UWY:St ptil{;h 

### win 8O'lve !the

### f,K)re l>h.t.&;8till! 

### and

### bJtoding**}}l~()blCilrt** 

### UStl'1!**'lj,~del' pit,~h** **cliiit$ly$.~** 

### does note!i1't'FIl1;11;te**d1ep~etra!\i()n o:falk~tU~rkh**  

### li\et'(l$(,l,ls deep tnte

# sell**C'~~aIY:$1eall:sitlg** 

### pore**pl~~jjg** 

### $d

### bltttldirtgpr.ob!eJliL'l,. 

### The irrtpactQfSltc!laett)$ols**Ih4'~** fJ;fI.."1$**thrt.)u~** 

### the**~eetrost.atic precipt~tot**  (ESP)

### (!Inthe l:tedbm'imlCf: (;1'

### kliW dllSt 

### SCR appHcttl'to!ll$ 

### wa..;;: not**clt~ussed** 

### b), H'alftoostetrli. '111isI]00 

### ash tha:t e$Capes '11"0111: the ESPts 

### fine';r thl!ltltllebun::**fiy~h** 

### and has a**hi~ler** 

### catlldysi**:t:ll~2"gin~ ~rote!lltial**  

### due to 

### ahigher

### rendenCJ'**t'!,)~...stOttle!'a't'e.** 

### In adcKtlQift. Hartenstein

### didnot

### oonsidet l.nfbrmaHo[i 

### provided(mif\)\Ij¢l'$VIDl b./U'fter**d~h~ reaet\~iI**  pitet,s:1lpstreJl;nll 

### te$1ltl¥ d:t!tt sho""ved**~ilkaH** fl0h**~\c<-'1tl'fiuhlttonS** &)'W'flStf't!am (,)f

### the Unit) 

### ESP at the 1\·iRY Stfltlt)H,
6. The Document erroneously claims that I suggested that "catalyst pitch will solve the pore plugging and blinding problems." However, the fact remains and was reiterated also by catalyst suppliers and SCR system vendors that proper catalyst selection is a critical issue in orderto avoid or at least minimize problems. No data was presented that shows any

page 6 of24

### such pore plugging and blinding problems ofcatalyst in a TESCR application. As a matter offact, absolutely no data was offered to substantiate the claimed impact of aerosols on TESCR catalyst. No representative data quantifying and/or characterizing such aerosols downstream ofan ESP and wet scrubberwas provided (see also pages A41 - A 45 ofmy original report). The data referenced from the Powerspan barrier discharge reactor pilot slipstream testing is notrelevant for TESCR as itwas obtained on MRYS Unit 

### 1 downstream ofthe ESP ratherthan on MRYS Unit 2 downstream ofthe wet FOD. Eventhough I never disputed thatthese aerosols will impactthe catalyst in aTESCR, the quantity ofsuch aerosols entering a TESCRmust be expected to be extremely small, which means their deactivation effectwill most likely be rather slow. Therefore, it can be expected with a very high degree ofconfidence that the catalyst lifetime in aTESCR will most certainly exceed 10,000 hours, which was randomly defined by the Department as a minimum time for successful operation. 

### 7. flnrteostetn's;**hlO\vlledie{tlfgas~oolid** 

### react'oo 

### iltJi"..chanisrns i'O 

### 'ronn sulfate

### andPYl'(}'.WI'f'ate**p'h~** in'situ

### in 

### SCR**cataty~sQwenrs:** tQ

### be lhnitC'd

### ;llIfid**w~** 

### nO't**.~equntelyaddr~~ed.** 

### 7. The gas-solid reaction mechanisms to form sulfate and pyrosulfate phase in-situ were not addressed since no data was provided that such formation of

### sulfates and pyrosulfates takes place in-situ in significant quantities in the catalyst in a TESCR. 

### 8. Hnrtensteindid t1(:tt

### discussihe recer/il**Hten~ture** 

### (linetltmlystpolsormingSludies inBurqpc**,~t)C:itUedwith Ctl'fJri;)~**  

### hJg31 

### mhH (Na $!ill<!: 

### K)**e¢'l1t~ifJin! bio~'S.**  

### -rhjs t-estifl;g h:a$ 

### sbowed :sjgnitk1mtJ)oJsolllinS of

### 'Catalysts duewaJ!kali**~f()ool pefJetr~Ul1**  l«Ut) 

### catalysts ;:uHl 

### me 

### subsequent relIiI.,'1:iO!i1 

### \vlthcntalyst**acth,~** Ol,)!ltt)l.)fif:bts**~us:ing .l:'OtOOl1in~.**  

### 8. Catalyst poisoning studies in Europe associated with co-firing high alkali (Na and K) containing biomass have clearly shown an accelerated catalyst deactivation in HDSCRs compared to European bituminous coal-fired units11, 12.. 

### However, neither did this lead to the conclusion that HDSCR is technically or economically infeasible nor did such accelerated catalyst deactivation occur in TESCRs.u, 14. 

### Units firing 100% biomass (i.e. wood and/or straw) with organically bound sodium and potassium contents as high or

11 Cleaner Fossil Fuel For Sustainable Development, CO-Firing Coal and Biomass, a presentation by Hemik Noppenau, Elsam (Energie E2 until 07/0112006 ), Denmark

g Washing Your Own Catalyst, a presentation Nathan White, Haldor Topsoe, NOx Round Table 2007,Cincinnati, Ohio

II Sobolewski, H, H. Hartenstein, H. Rhein, "STEAG's Long Term SCR Catalyst Experience and Cost", The 2005 EPRI Workshop on Selective Catalytic Reduction, Louisville, KY, 2005

11 Considerations for Catalyst Deactivation and Regeneration When Firing Biomass, Dr. Greg Holscher, CERAM and Mark Ehmschwender, Evonik Energy Services, 2008 NOx Round Table, Richmond, Virginia



### page 70f24

### even higherthan Center lignite have successfully operated even HDSCRsU' 16. 

### Wet bottom boilers equipped with TESCRs have experienced no effect on catalyst deactivation .as aresult ofco-firing biomass in Europell' ll. 

### 9. Hartenstein 

### didnot**off~r** 

### info:11l'tUlktn thatmQre

### dum**20~OOOMW** 

### ofli£1initeftred unitsin (jertl1nny wefe

### nQilrequired tQ**iu~U** 

### SCR. inorder

### to-

### coolply with the**n~tonal r~'l:IJ~ti(l1l,**  

### or 

### thateven ne\V

### Hgnite.:tlredunits**beifi~ :installed'~**  

### rn Gernmny

### ,are.not eqtlipped**wl~** 

### SCR ofany type.**f~** 

### did:I:tiQl**$t~te** 

### thatOeru\1:lfiYhadonly one**.cyc1Qn~fited** 

### botler**Qper~tng** 

### with


### aLDSCR (Wa!:w.nl Unit 1), Qr lhatthe 

### unit**b~s btlUt~tt}QlUsooal;**  

### nordidhe advisethat**VQh~rg** 

### Unit 3,a

### boilerin Austria firing 

### Ii;gnileroai, 

### ooly rail for a

### :short

### time 

### with a

### high. dustSCItand**'\\~** 

### sub.-requently :dmtooVi'l1 

### and dem<J,Ushed. He 

### SlatesthatTESCR**'h~\.i1fi(}IQg,y** 

### was "generally aoopted $: It

### univC'.rs$Uy aj}p1k..l!ble seR 

### oolutit,)n loraH 

### types. " ,. 

### 'but failedtolneooon**rllatlhC'~** 

### has neverbeen**~r** 

### TESCRil>uilt**~)e:r Sier~rf,**  

### ('which



### ..vas fjrtished 

### in**~dy** 1991 

### and

### has $1,lbsequentlybeendeoommisstoncd), tuthe Unit-eo $;lates
()J' Etit(>pe. 

### To the**b~** 

### ofour .lulO\\iledge. 

### there 

### is**~o** 

### TESCR l1ny\'V'here 

### in. 

### the V\.:'QuldOtt 

### a Hgfll'te-tlred 

### utility**11i(~J¢r.He** 

### cites 

### "Ceran'fs**ext~~sive** 

### expe1f'ietbce**'~l"ith** 

### Hgi'ttte.**:~, ~Ii'tft!l$l()**  report 

### :U:l!ftdtLlt

### OOl'tststs of'001yQi'te**p~ant** 

### ¥\Iith CeraID**c~tYSt** havi.ng**~l?er4'ted** 

### for**~l $~ml1**  

### p.:;:rtou of

### ttrne 00 Hgnhe 

### and a

### few**PI~ot** 

### prosrmu:li!.l. 

### ro 

### that

### itis dl,tlJ,iQt!$ t'Q**.~.** 

### tbat this**v~')r** 

### has eXI¢ijlSive

### ·ext'le;l'ience**~n** 

### lignite

### fired bofletSCRplants (see**i'~)f,en.dtx** 

### A). There liIre lrum(:rOI!J$ 

### otheJ'**i:l:\Sit!U}~$** (lif

### missingoi"**faetofdlyh!(~QrfeCi inf'Orm~lti'On**  

### attributed**~()** 

### Mr**H~u:'tefislein** 

### discit49sed in l'\ppendixA,
9. The lignite-fired units in Germany have to comply with the same NOx emission limit as all other fossil-fired units, namely 200 mg/Nm3 

### @ 

### 6% 02 

### (approximately 100 ppm)12, £Q.

u Cleaner Fossil Fuel For Sustainable Development, Co-Firing Coal and Biomass, a presentation by Henrik Noppenau, Elsam (Energie E2 until 07/0112006 ), Denmark

12 Washing Your Own Catalyst, a presentation Nathan White, Haldor Topsoe, NOx Round Table 2007, Cincinnati, Ohio

11 Sobolewski, H, H. Hartenstein, H. Rhein, "STEAG's Long Tenn SCR Catalyst Experience and Cost", The 2005 EPRI Workshop on Selective Catalytic Reduction, Louisville,KY, 2005

.lli Considerations for Catalyst Deactivation and Regeneration When Firing Biomass, Dr. Greg Holscher, CERAM and Mark Ehmschwender, Evonik Energy Services, 2008 NOx Round Table, Richmond, Virginia

12 Dreizehnte Verodmung zur DurchfUhrung des Bundes-Immissionsschutzgesetzes (Verordnung tiber GroBfeuerungsanlagen)

- 13. BImSchV. Bundesdrucksache BundersrepublikDeutschland, 1983 httQ:/lw\vw.zittu-darmstadt.de/cipp/tudzit/lib/all/lob/retum download.ticket,guest/bid,1179/check table,it chap downl embed/-/umwelttechnik.pdf



### page 8 of24Due to the specifics oflignite combustion, this limit could be met by most lignite-fired units (exceptions listed under 1. above) without the addition ofSCRs. However, currently the regulations are under review and it is expected that the emission limit will be reduced to 100 mg/Nm3 

### @ 6% O2 (approximately 50 ppm), which will most likely require the majority ofthe lignite-fired units to retrofit SCRs.
The statementthat "Germany had only one cyclone-fired boiler operating with a LDSCR (Walsum Unit 7)" is incorrect. Walsum Unit 7 is a U-fired wet bottom boiler ratherthan a cyclone-fired boilerll.
The statement that "Voitsberg Unit 3, a boiler in Austria firing lignite coal, only ran for a shorttime with a high-dust SCR and was subsequently-shutdown and demolished" is

. incorrect. Voitsberg Unit 3 operated with a HDSCR from 1990 to 2006, when it was temporarily shutdown as the lignite mine supplying the fuel ran out ofcoal. Voitsberg 3 is currently being converted to burning a blend ofbiomass and bituminous coal and is expected to restart operation in the near futurt#.
The statementthat "there has never been another TESCR built after Siersdorf, (which was finished in 1991 and has subsequently been decommissioned)" is incorrect as Le. VEB's Rudow Unit 2 was started up in 199421

, M. Legislation25 had required all units to meet the new NOx emission limit of200 mg/Nm3 by 1991, which is the reason why the vast majority ofthe utility boilers including Siersdorfwere retrofitted with SCRs by 1991. Nevertheless, additional utility units such as Rudow Unit 2 in Berlin were retrofitted with TESCRs later. Additionally, a vast variety ofother combustion processes were retrofitted with TESCRs between 1991 and today due to the universal applicability ofTESCRs.
The statement that CERAM'sexperience with lignite "consists ofonly one plantwith CERAM catalyst having operated for a,shortperiod oftime on lignite" is insofar interesting as it probably refers to Voitsberg Unit 3. However, what is considered a "short period oftime" seems to be very relative, since Voitsberg Unit 3's HDSCR was initially



### n Personal conversation with plant personnel at Evonik's Walsum Generating Station

n http://ww\.l.wirtschaftsblatt.at/homc/ocsterreich/unternehmen/stcicrmark/337197/index.do

II SCR Reference List, Fisia Babcock Environment GmbH http://64.233.169.104/search?q=cache:zdlt5N-ngCwJ:www.stadtentwicklung.berlin.de/umweltlumweltatias/e tab /t30 1e02.xls+Kraftwerk+Rudow-i-DeNOx&hl=de&ct-=cInk&cd=8&gl=us
Dreizehnte Verodmung zur Durchfiihrung des Bundes-Immissionsschutzgesetzes (Verordnung libel' GroBfeueruhgsanlagen)

- 13. BImSchV. Bundesdrucksache Bundersrepublik Deutschland, 1983

page 9 of24equipped with CERAM catalyst and in operation for 16 years between 1990 and 2006 while the unit burned Austrian**lignit~.** W. 

### Again. theEPA fails 10 

### rec()gtltzecoficlusivdy thai as:!:lchemical and physical propertres of the

### Texas lignite(Wrlcox h)rmattofi) 

### thatTXUpropose-s t<)

### burn atthe 

### new Oak C'oo\>'e p<)\verpllmtwhere SCR i;sbeInginstaUed (buthas m>tyetbegun**OfI'er~d:ioti)** 

### do flot repf'eseni '\lihut lS fired in 

### NQl1h Dakola. 

### Jmd lheretbretedmktU feasibiHty.**~nd** 

### expectedperformance**II~** 

### aTeX$**Ugnhe~fired** 

### pulverized

### coal :tx»ler

### SCiR. applic.'ll!()fi

### is: n<;-.ttrallsfemble to 

### North Dakota**Hgnite~fired** 

### cydone burnetunhs:**du~** 

### tothesignH'k:Mi differetlCt:S in t100gas and ash**Chemi~a1Md** 

### pbysh;.al properties. The**~omlp'Osition** 

### ofme**T~$li~ite** 

### fired ,at Marrinl,ake. 

### ""were

## sen.**mini~SCR** 

### p<il<:itrestinghasbeei\ conducted, 

### is tYp<ical t)fthe

### OOlnposhiQllQf Hgnite tlred 

### at**Sa.t~** 

### ...**v.~d1** 

### sodjum (t).'1de

### levels

### in**d~e** 

### Te:,'<i;"\$Hgntteashequal to O. '']Ok 

### The levelsofsodiuaYi oxide 

### in 

### ,Centerligniteaverage4,4% and c,an

### be ashi;g.h**~! 3~'Q**  

### in 

### Qs",tlred 

### samples. Hwnste1n (2008) :not

### pft)vtde 1nfbl'mattot} on**chen~ical** 

### oompOStt:iQll of

### any**'f~lsma;t** 

### are**eom~.ltble** to 

### high 

### sodhufiNO lignitew'here 8CRinstallutit)nhavebeen**mstaU~d** 

### andtested 'Of

### m!C¢':tl:3Sf'itUy**opee~ledL** 10. The fact that various units firing Texas lignite are being equipped with HDSCRs shifts the arguments to the different compositions between Texan and North Dakotan lignite. Even though biomass such as wood and straw have very similar ifnot higher sodium and potassium contents than ND lignite and are burned in boilers, which are equipped with HDSCRs and have successfully operated in Europe for some timell, Th 29, it is not necessarily relevant to provide such "information on chemical composition ofany fuels that are comparable to high sodium ND lignite where SCR installation have been installed and tested or successfully operated." It would be much more relevant to properly. characterize the flue gas downstream ofthe wet scrubber ofMRYS Unit 2 so that it could be compared to similar flue gases upstream ofsuccessful TESCR installations. However, such data properly characterizing the flue gas for a possible TESCR installation at MRYS was never provided.

l2 http://v;ww.wirtschaftsblatt.atlhome/oesterreich/unternehmenlsteiermark/337197/index.do

'Xl Cleaner Fossil Fuel For Sustainable Development, Co-Firing Coal and Biomass, a presentation by Henrik Noppenau, Elsam (Energie E2 until 07/01l2006), Denmark Washing Your Own Catalyst, a presentation Nathan White, Haldor Topsoe, NOx Round Table 2007, Cincinnati, Ohio

62 Considerations for Catalyst Deactivation and Regeneration When Firing Biomass, Dr. Greg Holscher, Cl:tRAM and Mark Ehmschwender, Evonik Energy Services, 2008 NOx Round Table, Richmond, Virginia

page 10 of24fi 1. 

### No

### examples \.Vt.re**rH'O'v~ded** 

### of**Cl¢l~Hne e~e,lulit\~**  

### ftlelhoos norcaialyst

### that would prove 

### res:i:stMtto dlUtlllge

### from $41d1meth.od$. 

### dmt 'w(iiuld beetl'{X.·:dve

### in**r~vitl£ $l,ii'r~e**  

### blinding**~d** 

### pore**plu-~ln£** 

### depostit$ such**~thQSe** 

### 'S;:.:m in 

### tbeC'Oyotepilottest**c~alyst** 

### ervenwhh the**:su~ed ed~e**  

### ert)s;it)ri

### prevMtion**~sul'e$in p'~aee.**  

### H$1s**H~:rtenS;tcin** 

### d<>esnot Mld:resschis issue ttl**hl:)cofi'itl'ien~** 

### Hartenstein impHes 

### irt his

### r¢p<trt {200S). 'thatc!ttl1'1ly&tthath{l!:> 

### been PQl$QIJ1ed by

### $()dhiliillcompooods 

### .panbe**l~gener~** 

### tn",sj.u, Uifid**th~** 

### this techniquei:$

### \veH 

### devclop;ed. There 

### ise.."<tt'emely limitedexperience within--situ,cataly&t**eloonin~** 

### on**c<rnl~Hr~1** 

### units. 

### n h$nevel' 

### be¢rt 

### usedr<:trbUnded

## etf ehenttcaltypoisoned**tatrd~~st~btJt** Oft!)' t"Q1' 

### trtedmnleJlUy pluggedcatalyst**{~e** 

### AppendixA}.
11. The statements that "there is extremely limited experience with in-situ catalyst cleaning on coal-fired units" and that "it has never been used for blinded or chemically poisoned catalyst, but only for mechanically plugged catalyst" are both incorrect. In-situ catalyst· regeneration for chemically (mostly sodium and potassium) poisoned catalyst has been successfully used in Europe since 1996JQ, 11 and is still used today. On-site ex-situ as well as in-suit catalyst washing is being regularly performed i.e. in Avedoere 2 in Denmark in orderto reverse the alkali poisoning, pore pluggage and surface blinding layers resulting from the biomass combustion32
• In-situ regeneration for the removal ofsurface blindin,? layers has been used in Europe successfully even in TESCRs for several years now33

, .L 35 as this process is ideally suited to remove highly water soluble constituents including alkali (sodium and potassium) and sulfate compounds from the catalyst.


### Specific Comments to the Document's Section "SCR Technology Review and Update":
The statement that "the reports provided by Hartenstein were notpeer reviewed and were derived primarily from companies who have vested interests in the SCR technology and typically do not

JQ Entwicklung und Einsatz eines Regenerationsverfahrens fUr SCR-Katalysatoren, Dr. Herwig Maier et. al., VGB Kraftwerkstechnik 1998

11. Reference List Catalyst Regeneration Integral Umwelttechnik GmbH

II Washing Your Own Catalyst, a presentation Nathan White, Haldor Topsoe, NOx Round Table 2007, Cincinnati, Ohio

11 Stadtwerke DUsseldorfAG, MUllverbrennungsanlage, a presentation by Uwe Behrendt SWD, Wildeshausener Katalysatortage 2008, Wildeshausen, Germany

M Regeneration von Katalysatoren im Rahmen einer KapazWitssteigerung, a presentation by Dr. JUrgen B5seke, 2008 Wildeshausener Katalysatortage, Wildeshausen, Germany
Was kann die Katalysatorregeneration zur Temperaturabsenkung beitragen?, a presentation by. Dr. Alexander Schuttig, Wildeshausener Katalysatortage 2008, Wildeshausen, Germany

page 11 of24discuss problems and challenges" is incorrect. The reports and literature cited was mostly authored or co-authored by utilities, EPRI, and other reputable industry organizations. Also, the majority ofHartenstein's publications were presented at reputable industry conferences such as the DOE SCR Conference, the EPRI SCR Workshop, the NOx Roundtable, the Mega Symposium, etc. most ofwhich require peer reviews ofthe paper priorto acceptance.
The mini-survey I conducted among the exact same experienced and knowledgeable SCR system suppliers and catalystmanufacturers contacted by Bums & McDonnell was obviously derived "from companies who have vested interests in the SCR technology." Also, the depth ofthe survey was not significant as time didn't permit a more detailed interrogation ofthe companies. However, the depth ofthe survey conducted by Bums & McDonnell among the exact same companies concerning HDSCR was not much greater either. It is therefore most interesting to note that the responses ofthese same SCR system suppliers and catalyst manufactures to the survey conducted Bums & McDonnell concerning HDSCR were considered unquestionably valid and indisputably correct by Burns & McDonnell for inclusion in their initial report while the responses by the same companies and often even the same individuals concerning TESCR are attempted to be disqualified as coming from people who "typically do not discuss the problems and challenges." This gives the distinct impression that the credibility and iptegrity of the companies and individuals, whose responses and technical comments were initially used by Bums & McDonnell's attempt to prove the technical infeasibility ofHDSCR, is now only being questioned because their responses concerning the technical feasibility ofTESCR don't seem to fit the agenda.
The entire section concerning the blinding and poisoning mechanisms including popcorn ash pluggage caused by large particle ash, pore pluggage potentially caused by very small fly ash particles, masking ofthe marcosurface and poisoning ofthe active sites as elaborated on pages 9 through 26 is certainly not being disputed concerning its scientific correctness. However, these arguments are all directed to catalyst installed in a HDSCR system and therefore largely irrelevant for catalyst installed in a TESCR system as the flue gas composition and characteristics are fundamentally different. Furthermore, even though correct, they don't prove by any means whatthe catalyst deactivation rate would be neither in an HDSCR nor in a TESCR. A much better approximation for the catalyst deactivation rate to be expected can be derived from full scale HDSCR data ofunits burning biomass with similar alkali contents. These units equipped with HDSCRs are successfully operated in Europe-and some actual full scale catalyst deactivation data has been published. Units equipped with TESCR co-firing biomass are operated successfully in Europe and some actual full scale catalyst deactivation data has also been published36
• As valid as all the described mechanisms and the·presented data may be for scientifically explaining the various types ofdeactivation they do not allow any definitive conclusions concerning the exact deactivation rate ofcatalyst installed in an HDSCR and even less so in a TESCR. More broadly worded, the presented arguments and data certainly support the

J§ Washing Your Own Catalyst, a presentation Nathan White, HaldorTopsoe, NOx Round Table 2007, Cincinnati, Ohio

page 12 of24expectation that catalyst deactivation in a HDSCR will be more rapid than typically observed for most sub-bituminous coals in HDSCR. Also, it is an indisputable fact that the combustion of many bituminous coals, particularly many Southern Illinois Basin coals containing high quantities ofarsenic and little calcium, result in much more rapid catalyst deactivation in HDSCRs than observed for most sub-bituminous coalsdl

. Several units in the U.S. burning Southern Illinois Basin coal.are known to have exchanged, regenerated or added catalyst in their HDSCRs well before an operating time of 10,000 hours was reached, which was randomly defined by the Department as a minimum time for successful operation. Just because the arsenic poisoning ofthe catalyst was more rapid than initially expected, this doesn't mean the HDSCR operation ofthese units has been unsuccessful and these plants continue to operate this way. The most obvious solution for the stated problem ofthe claimed catalyst deactivation rate resulting from burning ND lignite results from various fly ash particle-bound mostly alkali compounds would be to remove as much ofthe fly ash particles as possible upstream ofthe SCR. This can easily be accomplished by means ofan ESP orbaghouse and a wet scrubber in orderto minimize the effect ofthese fly ash particle-bound compounds. The result is a TESCR.
The biomass dataprovided in the Document is very useful as it offers some insight into the possible deactivation rates ofa HDSCR that could be eXfsected at MRYS. Since HDSCRs have been in operation on biomass fired boilers since 2001 38

, ....2, this allows some composition comparison ofbiomass (Le. wood)and ND lignite. The fuels listed in Tables 2 through 5 ofthe Document are mostly woods ofvarious types. A comparison to ND lignite is shown in the table below. As stated in the Document, wood is similar to ND lignite in its composition and variability

. Center lignite Biomass woods) Historical Future Range average Heating value fl0b Btu/lb] 13.2 13.4 6.8

- 9.1 8.3 Ash content f%wt.] 9.6 7.8 0.3

- 20.4 6.0 CaO f%wt. in ash] 13.2 17.0 5.8

- 49.9 20.9 K2 0 f%wt. in ash] 1.3 1.0 0.2

- 22.4 7.7 MgO f%wt. in ash] 4.0 5.1 1.8

- 18.4 4.3 Na20 f%wt. in ash] 4.4 5.6 0.1

- 23.5 3.1
Likewise is the association ofalkali and alkaline earth elements in Center lignite similarto the associations found in biomass. Thus, it seems to be not unreasonable to expect that the catalyst

II Kramer, M., C. Gerlach, H. Hartenstein, "As,03 and S03 Testing at Hoosier Energy's Merom Generating Station", The 2007 EPRI Workshop on Selective Catalytic Reduction, Pensacola, FL, 2007

1§. Cleaner Fossil Fuel For Sustainable Development. Co-Firing Coal and Biomass, a presentationby Henrik Noppenau, Elsam (Energie E2 until 07/0112006), Denmark

:l2 Washing Your Own Catalyst, a presentation Nathan White, Haldor Topsoe, NOx Round Table 2007, Cincinnati, Ohio·

page 13 of24deactivation in HDSCRs installed on units burning 100% biomass ofsimilar composition and variability should be similar to the one ofcatalyst in a HDSCR burning ND lignite.
The deactivation rate ofthe HDSCR catalyst at Elsam's Avedoere Unit 2 was found to be about 25% per 8,000 HDSCR operating hours when burning 100% biomass (mostly wood and some straw) while it was found to be only about 10- 11% per 8,000 HDSCR operating hours when burning 100% bituminous coal40
• Thus, the catalyst deactivation was found to be about 2.5 times higher for biomass than for bituminous coal. However, a catalyst deactivation ofaround 25% per 8,000 HDSCR operating hours has also been observed for several units in the U.S., particularly for those burning high arsenic coal without limestone mitigation. In other words the full scale HDSCR catalyst deactivation experience ofa unit burning 100% biomass, which is very similar and therefore directly comparable to ND lignite, was found to be virtually identical with the full scale HDSCR catalyst deactivation ofmany U.S. units burning high arsenic bituminous coal. Needless to say that the catalyst deactivation to be expected in a TESCR where virtually all of the fly ash associated particle-bound compounds have been removed upstream ofthe catalyst will be considerably less.
There is no question that the flue gases from combusting ND lignite will cause a relatively rapid catalyst deactivation ofa HDSCR catalyst. However the rate ofcatalyst deactivation is indisputably a function ofthe mass flow ofcatalyst poisons, which is dramatically reduced in a TESCR compared to a HDSCR.


### Specific Comments to the Document's Section "Variability ofLignite":
The Document incorrectly quotes me and my "experience with German Ruhr Brown coal as described in a paper by Hartenstein and others (1999):" Besides the fact that German Ruhr·coal is bituminous coal and not brown coal or lignite as incorrectly indicated in theDocument, the paper describes the effect ofalkali compounds on the adhesiveness offly ash, which in combination with the incorrect catalyst selection resulted in physical pluggageproblems. Catalyst deactivation due to these alkali compounds occurred only during start-up and shut down ofthe units when the flue gas went through the dew point. This results in the mobility ofthese highly water soluble compounds and the reaction with in water dissociated alkali ions (Na+, K+) with the catalyst's active compounds 

### V20S.
Neither ofthese two issues, however, caused the technical or economical feasibility ofHDSCR to be questioned. The pluggage issue was resolved by the selection ofthe correct catalysttype and pitch and the catalyst deactivation was mitigated by limiting the number oftimes the flue gas inside SCRreactor went through the dew point. Both issues were already pointed out in my report.

1Q Washing Your Own Catalyst, a presentation Nathan White, HaldorTopsoe, NOx Round Table 2007, Cincinnati, Ohio

page 14 of24

### Specific Comments to the Document's Section "Results ofthe Coyote Pilot Testing":
The Document quotes me as describing the Coyote Pilot Testing as "ill-designed." This quote is certainly correct but only repeats me quoting the Department who characterized the Coyote Pilot Testing as "ill-designed" (page 7 second line) and concluded that it "didn't provide much useful data" (page 7, first line). This view was confirmed by catalyst suppliers such as CERAM and SCR system suppliers such as Babcock Power. I agree with this view regardless <;>fwho was all involved in or reviewed the design ofthe test reactor and the test. The fact alone thatthe catalyst was too plugged for Haldor Topsoe to perform activity testing proves that not much useful data could be derived from the test. In essence the only useful result ofthe Coyote Pilot Tests seem to have been that it was recognized that a 6 mm pitch catalyst is not suitable for a HDSCR application featuring highly adhesive fly ash. Not surprisingly, this is a very similar result as described in my 1999 paper for E.ON's (not RWE's as erroneously claimed in the Document) Staudinger Generating Station Units 1 and 2 where the pluggage problem was solved by either a different coal blend or by installation ofa 10 mm pitch catalyst as shown in Figure 11 ofsaid pape#.


### Specific Comments to the Document's Section "Soluble Sodium":
This section describes in detail the effects ofsoluble sodium on catalyst in a HDSCR installation. While these described effects are not disputed, the section, however, fails to provide any data that allows for estimating a catalyst deactivation rate in a HDSCR. Furthermore, it doesn't even address the issue ina TESCR as most water soluble sodium compounds will be removed in the wet scrubberupstream ofa TESCR and thereforeare unlikely to pose a rapid deactivation threat for TESCR catalyst.


### Specific Comments to the Document's Section "Differences in Flue Gas Composition":
The Document fails to allude to what differences there may be between flue gases from combusting ND lignite and flue gas from combusting biomass. As a matter offact the Document states that "the abundance ofrich alkali aerosols is similar to that found in biomass combustion systems." As described earlier, HDSCRs have been in successful operation for several years in units burning 100% biomassQ 1J., which renders the Document's claim invalid that no examples exist ofa fuel fired in a boiler that produces a flue gas that is characteristic offlue gases produced from ND lignite where SCR has been installed and successfully operated.

11 Hartenstein, H., H. Gutberlet, "Utility Experience with SCR in Germany", DOE Conference on SCR/SNCR,

. Pittsburgh, PA, USA 1999
Cleaner Fossil Fuel For Sustainable Development, Co-Firing Coal and Biomass, a presentation by Henrik Noppenau, Elsam (Energie E2 until 07/0112006), Denmark

.1l Washing Your Own Catalyst a presentation Nathan White, HaldorTopsoe, NOx Round Table 2007, Cincinnati, Ohio

page 15 of24

### Specific Comments to the Document's Section "CatalystPoisoning, Blinding and Plugging" and Applicability ofSCR Development for Texas Lignite": Again, both ofthese sections refer only to HDSCR and entirely ignores thatthese issues are much less ifnot irrelevant in a TESCR application.


### Specific Comments to the Document's Section "SCR Catalyst Erosion and Cleaning":
This section refers also only to HDSCR and ignores TESCR. However, it also incorrectly claims that catalyst does not withstand highly erosive flue gas and/or on-line cleaning measures such as aggressive sootblowing. HDSCR systems are successfully operated on boilers burning coals with up to 30% ash, which not only creates a highly erosive flue gasbut also requires very aggressive sootblowing. Properly selected catalyst has been shown to withstand this without major erosion damage formany**years~.** . The Document also claims incorrectly thatEnBW in Germany developed an in-situ cleaning technique, which has never been a commercial success. As pointed out earlier, simple catalyst washing either in-situ or on site is an effective method to quickly remove alkali poisoning from the catalyst. This has been demonstrated for more than a**decad~** 1Q, fZ, 12 and is currently**re~ularly** used for units with HDSCRs burning biomass in Europe (i.e. Elsam's Avedoere Unit 2)...Q. In-situ regeneration is also used within the EdF group including EnBW and numerous operators ofvarious smaller SCRs Le. in waste-to-energy**plantsn,g,~.**

Personal conversations with plantpersonnel at Evonik's Fenne, Heme and Walsum Generating Stations Entwicklung und Einsatz eines Regenerationsverfahrens fUr SCR-Katalysatoren, Dr. Herwig Maier et. aI., VGB Kraftwerkstechnik 1998

.
.1§ Successful experience with In.situ Regeneration ofSCR Catalyst in Coal-Fired Applications, Dr. Herwig Maier et. aI., EnBW, 2000 DOE Conference on SCR/ SNCR, Pittsburgh 2000

£ Recent Experience with SCR Catalyst Regeneration, Dr. Herwig Maier et. aI., EnBW, 2001 DOE Conference on SCR/ SNCR, Pittsburgh 2000
Reference List Catalyst Regeneration Integral Umwelttechnik GmbH
Mobile Katalysatorregeneration in der praktischen Bewahrung, Dr. Herwig Maier et. al. EnBW Kraftwerke AG, VGB Konferenz Chemie im Kraftwerk, 2006

iQ Washing Your Own Catalyst a presentation Nathan White, HaldorTopsoe, NOx Round Table 2007, Cincinnati, Ohio

it Stadtwerke DiisseldorfAG, Miillverbrennungsanlage, a presentation by Uwe Behrendt SWD, Wildeshausener Katalysatortage 2008, Wildeshausen, Germany

page 16 of24

### Specific Comments to the Document's Section "Pilot Testing for SCR Catalyst":
It is interesting that Burns & McDonnell disagrees with all the catalyst suppliers and SCR vendors that pilottesting is not needed for TESCR atMRYS while Burns 

### & McDonnell in its attemptto prove the technical infeasibility ofHDSCR at MRYS relied heavily on exactly the same catalyst suppliers and SCR vendors.


### Specific Comments to the Document's Section "Vendor Guarantees":
Both seem to imply that vendors lightly guarantee anything without hesitation, which is inconsistent with my experience. To the contrary in my experience vendors do not lightly and without hesitation guarantee anything but carefully considertheirprocess performance guarantees. In my opinion, the vendors would not suggest TESCR as technically feasible and available for this application ifthey would not be willing to provide the proper associated process performance guarantees. What benefit would the queried vendors derive from suggesting

. that TESCR would be technically feasible and available for MRYS ifthey would not be willing. to provide the proper associated process performance guarantees at the same time?


### Specific Comments to the Document's Section "Temperature Variation for HDSCR":
As already stated in my report HDSCR will not work at MRYS without a solution for the temperature variation problem such as for example adequately modifying the 90iler's economizer sections.


### Specific Comments to the Document's Sections "Burns & 

### McDonnell's SCR Experience" and "Comments by Sargent and Lundy on SCR Experience:
Neither one ofthese two AlEfirms disputes my claims thatthey have no SCR operating experience and have never provided any SCR system or catalyst performance guarantees ofany kind.

Regeneration von Katalysatoren im Rahmen einer Kapazitatssteigemng. apresentation by Dr. JUrgen Boseke, 2008 Wildeshausener Katalysatortage, Wildeshausen, Germany
Was kann die Katalysatorregeneration zurTemperaturabsenkung beitragen?, apresentation by Dr. Alexander Schuttig, 2008 Wildeshausener Katalysatortage, Wildeshausen, Germany

page 17 of24

### Specific Comments to the Document's Section "Comments on Hans Hartenstein's Qualification for Expert SCR Opinions":
No comment.


### Specific Comments to the Document's Section "Fuel Switching":
No comment.


### Specific Comments to the Document's Section "Non-SCR NOx Controls":
No comment.


### Specific Comments to the Document's Section "Conclusions":
No comment.


### Specific Comments to Appendix A "Qualifications"
The author erroneously claims that "all waste-to-energy plants in Europe have either activated carbon injection or fixed activated carbon plants", which "take out all the poisons such as all acidic components, arsenic etc. from the flue gas" upstream ofthe SCR. This statement is incorrect since many waste-to-energy units in Europe have:
TESCRs directly. downstream ofa wet scrubber and no activated carbon injection or fixed bed activated carbon plants upstream ofthe SCR. The waste-to-energy plants AEZ Asdonkshof, Germany and MVA Bielefeld-Herford, Germany may serve as examples for this TESCR**arrangement~** 22.
LDSCRs directly downstream ofthe ESP and upstream of the acid gas removal system. The waste-to-energy plants KVA Basel, Switzerland and MVA Wtirzburg, Germany may serve as examples for this LDSCRarrangement56 il.

http://www.aez-asdonkshof.de/mva.html

22 Regeneration von Katalysatoren im Rahmen einer Kapazitatssteigerung, a presentation by Dr. Jiirgen Boseke, 2008 Wildeshausener Katalysatortage, Wildeshausen, Germany http://\-\-vi\N.iwb.ch/site/rundgang!rundgang.php

2. http://www.zvaws.de/verbrennung.html

page 18 of24HDSCRs directly downstream ofor even integrated in the boiler. The waste-to-energy plant MHKW Mainz, Germany may serve as an example for this HGSCR

### arrangement~.
Specific Comments to Appendix A "Missing Information"
The author claims that "more than 20,000 MW oflignite fired units in Germany were not required to install SCR in order to comply with the regulations." Even though this statementis correct the following statement that "these units were exempted from the regulation despite the fact that they would not achieve the required emission limit of200 mg/Nm3" is simply incorrect. Correct is that the lignite-fired units have to meet the same NOx emission limit of200 mg/Nm3

, however have been able to achieve this with primary measures only such as low NOx**burners~.** The author erroneously claims that "Germany had only one cyclone-fired (slag tap) unit with a SCR system. This unit is Walsum 7, the NOx control system is a LDSCR." Evonik's Walsum Unit 7 a U-fired and not a cyclone fired wet bottom boiler. It is equipped with a LDSCR with flue gas reheating downstream ofa cold";side ESp2Q. However, numerous cyclone:fired units with HDSCRs and TESCRs exist in Germany. At least two units, namely E.ON's cyclone fired Staudinger Units 1 and 2 equipped with HDSCR should be known to the author as they are extensively discussed in my 1999

### pape~. The author erroneously claims that one "cannot send saturated gas from the scrubberto the gasgas heat exchanger (GGH) for the TESCR." In the following paragraph the author continues to erroneously claim that "there is no TESCR on any utility boiler anywhere in the world that uses this configuration successfully downstream ofa wet FGD." Eyonik's Marl Units 3, 4 and 5 may serve as one ofmany plants where exactly this has been successfully in operation for over 20 years**no~.** The flue gas from the wet scrubber enters an axial booster fan upstream ofthe TESCR GGH. In order to avoid any CaS04 deposits on the fan blades, a small amount offlue gas is recirculated from downstream ofthe TESCR back to upstream ofthe booster fan. However, many wet FGDs in Europe are equipped with GGH around the scrubber, thus cooling the flue gas prior to entering the scrubber and reheating immediately afterleaving the scrubber. In all ofthese GGHs the wet, saturated flue gases coming from the scrubber enter the GGH's heating surfaces. Ofcourse regular on-line washing is necessary to keep the heating surfaces clean, which, however, is no differentthan on-line sootblowing in a boiler. These systems have

2l! http://www.mhkw-mainz.de/anlagetechnik!index.php

.22 Dreizehnte Verodmung zur Durchfiihrung des Bundes-Immissionsschutzgesetzes (Verordnung tiber GroBfeuerungsanlagen)

- 13. BImSchV. Bundesdrucksache BundersrepublikDeutschland, 1983

§Q Personal conversation with plant personnel ofEvonik's Walsum Generating Station

§l Hartenstein, H., H. Gutberlet, "Utility Experience with SCR in Germany", DOE Conference on SCR/SNCR, Pittsburgh, PA, 1999
Personal conversation with plant personnel ofEvonik's Marl Generating Station

page 19 of24been in successful operation for more than 25 years now so that this must be considered a well proven concept. Interestingly enough the author acknowledges the existence ofthese FGD GGHs, which are exactly the same piece ofequipment as the TESCR GGH, however, he fails to explain why the FGD GGHs work well and the TESCR GGHs wouldn't.
The author also erroneously states that "the required FGD removal efficiency was about 80%." The fact ofthe matter is that the minimum required SOx removal efficiency hasbeen 85% regardless ofthe SOx concentration in the flue gas since 198363
• Likewise the maximum permissible SOx outlet concentration .atthe stack was 400 mg/Nm3 (-140 ppm) between 1983 and 2004 and 200 mg/Nm3 (-70 ppm) since 200464
•This means that the SOx removal efficiency at full load and design coal has typically been well above 90% and in many cases above 95%, with a minimum of85% even at very low SOx inlet concentrations.


### Specific Comments to Appendix A "Incorrect Information" My comments mostly address only issues that weren'taddressed earlier already and are relevant for the discussion.
The author claims that it is incorrect that no flue gas reheating is typically required for HDSCR and LDSCR. Since the vast majority ofthe coal-fired units equipped with SCRs in North America are base loaded units, they typically run at full or close to full load for the majority of the time. In this operating mode typically no flue gas reheating is required. Also, economizer bypasses or split economizers are commonly not considered as flue gas reheating since no
. additional heat energy is added to the flue gas but only the amount ofheat energy extracted from the flue gas is limited during low load operation.
The author erroneously claims that "not a single coal-fired unit with a LDSCR orTESCR system has a heat exchanger otherthan rotary." This statement is incorret and E.ON's Westerholt Power Station Units 1 & 2, which had TESCRs equipped with Balcke-Dlirr plate type cross flow GGHs, may serve as an example. The 150 MW wet bottom boiler units were built in the early 1960, retrofitted with wet FGDs and TESCRs in the late 1980s and decommissioned and demolished in 2006 after almost 45 years of**servic~,** QQ.

§l Dreizehnte Verodrnung zur Durchfiihrung des Bundes-lmmissionsschutzgesetzes (Verordnung tiber GroBfeuerungsanlagen)

- 13. BlmSchV. Bundesdrucksache Bundersrepublik Deutschland, 1983

M NoveIIierung der Dreizehnten Verordnung zur Durchfiirhrung des Bundes-Immissionsschutzgesetzes (Verordnung tiber GroBfeuerungs- und Gasturbinenanlagen

- 13. BlmSchV, Bundesdrucksache Bundesrepublik Deustchland,.2004
Press release 10/08/200, Abschaltung des Kernkraftwerks Stade im Jahre 2003 geplant, E.ON Energie AG; Hamlover, Germany

.§§ https:/!www.etde.org/etdeweb/details.jsp?osti id'=542243:l

page 20 of24The author obviously misunderstood my comment about the possible elimination ofthe heat rate penalty in case ofa turbine limited unit. It is certainly correctthat the more heat input is necessary for the same electrical output. What I meant to point out·is that incase ofturbine limited units, it is often possible to maintain the same electrical outputdespite using steam for reheating ratherthan having to reduce the electrical output ofthe unitas a result ofthe steam consumption for reheating.
The author erroneously claims that "there has never been another TESCR built after Siersdorf, which was finished in early 1991, in the U.S. or in Europe." As already pointed out previously, VEB's Rudow Unit 2 was retrofitted with a TESCR in 1994§1. Afterthat numerous TESCRs were retrofitted to a wide variety ofcombustion process including at least one unit in North America, namely the waste-to-energy plantKMS Peel Units 1 through 5. in Mississauga, Ontario, which has been in successful operation since 2001 68
• It is also worth noting that even though Siersdorfwas shut down, the catalyst, which was installed in these TESCRs still remains in operation today since no significant deactivation was observed. The TESCR catalyst originally installed in Siersdorfwas installed in Evonik's Voerde Generating Station's Units West 1 and 222

. . 

### Specific Comments to Appendix A "Vendor Guarantees"
No additional comment as this was already addressed previously.


### Specific Comments to Appendix A "Catalyst Poisons and Pilot Projects"
No additional comment as this was already addressed previously.



### References and Literature Considered
1. Cleaner Fossil Fuel For Sustainable Development, Co-Firing Coal and Biomass, a presentation by HenrikNoppenau, Elsam (Energie E2 until 07/0112006 ), Denmark
2. Co-firing ofbiomass -evaluation offuel procurement and handling in'selected existing plants and exchange ofinformation (COFIRING)

- Part 2, Kraftwerk Schwandorf, Germany, Alterne ABV-NET V, Ruth Brakeland, C.A.R.M.E.N.

§1 SCR Reference List, Fisia Babcock Environment GmbH Chandler, 1., J. Gallant, H. Hartenstein, A. Licata, "Retrofit ofa WTE Facility with SCR for NOx and PCDDIF Control andNa2S4 Injection for Mercury Control", DOE Conference on SCRlSNCR, Pittsburgh, PA, 1999
22 Personal conversation with plant personnel atEvonik's Voerde Generating Station

page 21 of243. Considerations for Catalyst Deactivation and Regeneration When Firing Biomass, Dr. Greg Holscher, CERAM and Mark Ehmschwender, Evonik Energy Services, 2008 NOx Round Table, Richmond, Virginia
4. Dreizehnte Verodmung zur DurchfUhrung des Bundes-Immissionsschutzgesetzes (Verordnung tiber GroBfeuerurrgsanlagen)

- 13. BImSchV. Bundesdrucksache Bundersrepublik Deutschland, 1983
5. Novellierung der Dreizehnten Verordnung zur DurchfUrhrung des BundesImmissionsschutzgesetzes (Verordnung tiber GroBfeuerungs- und Gasturbinenanlagen

- 13. BImSchV, Bundesdrucksache Bundesrepublik Deustchland,.2004
6. Entwicklung und Einsatz eines Regenerationsverfahrens fUr SCR-Katalysatoren, Dr. Herwig Maier et. aI., VGB Kraftwerkstechnik 1998
7. Katalytische Dioxinzerstorung fUr Abfallverbrennungsanlagen, Dr. R. Spahl et. al. BASF, Sonderdruck aus EntsorgungsPraxis 5/93, 1993
8. Kramer, M., 

### C. Gerlach, H. Hartenstein, "As203 and S03 Testing at Hoosier Energy's Merom Generating Station", The 2007 EPRI Workshop on Selective Catalytic Reduction, Pensacola,FL,2007
9. Landesamt fUr Umweltschutz Nordrhein-Westfalen, Klarschlammbericht 2003
10. Landtag Nordrhein-Westfalen Drucksache 13/6936, Antwort der Landesregierung aufdie Kleine Anfrage des Abgeordneten Reiner Priggen, GRONE, Drucksache 13/6716,2005
11. Mitverbrennung von Klarschlamm in kalorischen Kraftwerken, Umweltbundesamt GmbH, Wien, ISBN 3-85457-614-5
12. Mobile Katalysatorregeneration in der praktischen Bewahrung, Dr. Herwig Maier et. al. EnBW Kraftwerke AG, VGB Konferenz Chemie im Kraftwerk, 2006
13. Press release 10/081200, Abschaltung des Kemkraftwerks Stade im Jahre 2003 geplant, E.ON Energie AG; Hannover, Germany
14. Recent Experience with SCR Catalyst Regeneration, Dr. Herwig Maier et. aI., EnBW, 2001 DOE Conference on SCR / SNCR, Pittsburgh 2000
15. Reference List Catalyst Regeneration Integral Umwelttechnik GmbH
16. Reference List SCR, Fisia BabcockEnvironment GmbH

page 22 of2417. Regeneration von Katalysatoren im Rahmen einer KapaziUitssteigerung, a presentation by Dr. JUrgen Boseke, 2008 Wildeshausener Katalysatortage, Wildeshausen, Germany
18. Retrofit ofa WTE Facility with SCR for NOx and PCDOIF Control and Na6S4 Injection for Mercury Control, Chandler, J., J. Gallant, H. Hartenstein, 

### A. Licata, DOE Conference on SCR/SNCR, Pittsburgh, PA, 1999
19. Stadtwerke DUsseldorfAG, MUllverbrennungsanlage, a presentation by Uwe Behrendt SWD, Wildeshausener Katalysatortage 2008, Wildeshausen, Germany
20. STEAG's Long Term SCR Catalyst Experience and Cost", Sobolewski, H, H. Hartenstein, H. Rhein, The 2005 EPRI Workshop on Selective Catalytic Reduction, Louisville, KY, 2005
21. Successful experience with In.situ Regeneration ofSCR Catalyst in Coal-Fired Applications, Dr. Herwig Maier et. aI., EnBW, 2000 DOE Conference on SCR 

### 1SNCR, Pittsburgh 2000
22. Utility Experience with SCR in Germany, Hartenstein, H., H. Gutberlet, DOE Conference on SCR/SNCR, Pittsburgh, PA, USA 1999
23. Washing Your Own Catalyst, a presentation Nathan White, HaldorTopsoe, 2007 NOx Round Table, Cincinnati, Ohio
24. Was kann die Katalysatorregeneration zur Temperaturabsenkung beitragen?, a presentation by Dr. Alexander Schuttig, Wildeshausener Katalysatortage 2008, Wildeshausen; Germany
25. Workshop VI SCR: Catalyst Poisoning, Jeffvan Aaken, Argillon, 2007 NOx Round Table, Cincinnati, Ohio
26. Website 

### http://64.233.169.1 04/search?q=cache:zdlt5NngCwJ:www.stadten1wicklung.berlin.de/umwelt/umwelta11as/e tab 

### 1130 1e02.xls+Kraftwerk+Rudow+DeNOx&hl=de&ct=clnk&cd=8&gl=us
27. Website http://www.aez-asdonkshof.de/mva.html
28. Website http://www.eon-energie.com/pages/eea de/Presse/Pressemitteilungen/Aktuelle Presse/PressemitteiI1l11g.htm?id=49380
29. Website https:lh;vww.etde.org/etdeweb!details.jsp?osti id=5422433
30. Webiste http://www.iwb.ch/site/rundgang/rundgang.php
31. Website http://www.mhkw-mainz.de/anlagetechnik/index.php

page 23 of2432. Website http://www.spiegel.de/politik/deutschland/O. 1518.97338.00.html

. 33. Website http://\vww.stmk.spoe.atlsteiermark/aktuelles/archiv/grose-chance-fur-neuearbeitsplatze-durch-kovats-engagement-beim-kraftwerk-voitsberg
34. Website http://www.wirtschaftsblatt.atlhome/oesterreich/untemehmen/steiermark/337197/index.do
35.

.Website http://www.zittu-dannstadt.de/cipp/tudzit/lib/allliob/retum download,ticket, guestlbid,1179/check table,it chap downl**embed/~/umwelttechnik.pdf** 36. Website http://www.zvaws.de/verbrennung.html

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