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 of Public 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! of Minnkota's letter on September 26,2008. Although Minnkota submitted

its comments nearly two months after the public comment period closed, EPA understands that

NDDH intends to include Minnkota's response in the administrative record for the final BACT

determination.

EPA understands that NDDH 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 in paragraph 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 Per July 8, 2008 letter from NDDH to EPA, the public comment period 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 provided NDDH 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 or provide any additional data or facts substantiating the

claim that 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 of Significant Deterioration and Nonattainment Area Permitting," (Draft October

1990), (EPA's NSR Manual).3 Vendor responses and actual operating examples4 related to tailend SCR presented 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. If you would like to discuss any ofthese matters, please call Cynthia Reynolds at

(303) 312-62006 or Brenda Morris at (303) 312-6891.

Sincerely,

~T~

AndrewrM. 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 of commercial availability and technical feasibility of a control

technique and could contribute to a determination oftechnical feasibility or technical 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)

Brenda Morris, 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 of24
General Remarks

This report was prepared after reviewing 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 of deactivation 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 of any 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 of SCR applications and

extensive experience worldwide.

Specific Comments to the Document's Section "Corrections, Clarifications and Omissions

of Hartenstein 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 ofSCR syst~ ijlsrnlled ttl EI.1fO<PC. This is misleOOingaod substlm!tiIldJ)'looorrect.

VCJ)' few ofth-e mart()' SeRs tetrofh in Eun;)pe we.J'¢ instnUed on li~~ite.cfired utiHty 00i1er:s-.

TlJIcktk;k:5; b~ advised lbat lo dlJe best of~helr bowledg,:e. they area\Vare (}fSCR being

o:d~inaUy installed at 0111y ('V;i() plftll'tS\, rmdneitber ofthese ptams is OiJ:J<ei'aitlonQl t'Qcday..

page 2 of24
1. 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 of coal. It is

currently being converted to a blend of bituminous 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 dust SCEsln the

Unit,ed Staih~$ 'f!WJd are 'C(;rt'fli~~to~he YOllfi8 Smdon b<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$~e iiot ~ble to ¢QJel"aIDethe high$' 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 of alkali

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 Md Hartenstein 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~ species pr,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,<nstreamofa'wet serubber, bave been

devek~~d b'jlc;niUyst vendOfi;;,

1 Co-firing of biomass - 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. of24
3. 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 present anymore. Therefore, the amount of

particles available for pore pluggage and the formation of a 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 of catalyst 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 of very 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 of pore pluggage and blinding of SCR 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, Haldor Topsoe, 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> he cUd flOt~ndersl4lfld how soluble ~l<lhim is used t~) .oofme

the aboodlmce of (yJ:'~fiic2n:y ,QS$()dnted ~lum iu Hgnite and hO\v ~dhlm \\>ill v~ because

(ifthe abUilldance (yfother IOfil.'iiilg C~fi1j)t~fitS in·~ {)oa1. Tbe ;abund~)ce ofsoditun

~nd other ash furming: 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:\derstand the differ.ene~ betvi'eet'i f()rtUrlt()fi lignite and Texas lUgn:ite. HelildiCllte$ that

the lti$t~la:tJoo$ ofSeR on Powder River B$$ifi (PRB}subbiturrunous,coal MdtestingOifl

T~$lignlte tnd1<:ate f~bilhy tor SCR Q-U ND lignite eVeJi though the lcve~$· ofsodium in

typkal PRB (:o~l ¥lIJJd Texl!Is Ugcites lltre V{}ty low (0.7 to 15% NatO:' as CQI'tIpl'U'ed to 4.4 %

NazO for Center lignite. The: ,u:mourat f{)rm i..)(oltalls:p.edes in tbe 0011d ~Otlg. wid1 .

oombusliOfi pr\l'O~ it'ifh.letLOCefhelf ability to be enriched bi d:veaCifOooi ilnd f'lrie p~rricle

ft'~cti:()n of.he: ·f1.)1 ash, The s4:ze: 4Ifld CQfftpositioll 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 directed towards 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 SCR technology 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.

.!! 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, Haldor Topsoe, 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 tiM l1otaddre$s the issue ofehepat1it1ooing of ash--furmmg species bet\\'een the

:s4a.gand fly ash oomponents in <::yclone~f1red Sj'stems .nat resule man eJlrid'unentof$Odium

.and othcr f'lart\e':\?Qlattli2ed speciesiU the fh.ie gas. These fltUne~v{)l~tUized spe.cics wIH

OOl1dense ho:ttlO<geneously to s>roduve abundant sodium and pota,....~lum~rieh aerosols because

()f the h't'I.I/¢.f level {)fentrained soHdash partidesin tycl~ combustlc,n·<Ieri"'e<l flue gases

,'eh'ttive t{> pulvcri2e'.d coal Ct)mbm:tto;tl derived flue ~_

5. The purpose ofmy report was not to discuss the partitioning of ash-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 of an ESP and wet scrubber, these issues are of

little if any relevance for the deactivation ofTESCR catalyst by fly ash particle-bound

compounds.

6. Bartenstcin did ~(}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 ai~nite) coots fired in

(.,j.rcJ()11:e~f:ifed ihoi let'S ,is the abm'idIDICeof ~kaH-flch 11erOSt)lsiifh lil:e flue gas thM CM peilleltlilte

JtlilO ;dle pores()f SCR c~!udyst (4ltlsing blinding ~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 not be fnmtHa,r l.vhh th,e diffhsaon

meclmnism ottrat1:Si,fXtrt QfIiIe:JXlISt)ls doop tti,lO the OCR eatl!dySots that 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 not e!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 bltttldirtg pr.ob!eJliL'l,.

The irrtpact QfSltc!laett)$ols Ih4'~ fJ;fI.."1$ thrt.)u~ the ~eetrost.atic precipt~tot (ESP) (!In the

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!ltltlle bun:: fiy~h and has a hi~ler catlldysi :t:ll~2"gin~

~rote!lltial due to a higher rendenCJ' t'!,)~...stOttle!'a't'e. In adcKtlQift. Hartenstein did not 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 order to avoid or at least minimize problems. No data was presented that shows any

page 6 of24
such pore plugging and blinding problems of catalyst 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 of an ESP and wet scrubberwas provided (see also pages A 41

- A 45 ofmy original report). The data referenced from the Powerspan barrier discharge

reactor pilot slipstream testing is not relevant for TESCR as it was obtained on MRYS

Unit 1 downstream ofthe ESP rather than on MRYS Unit 2 downstream ofthe wet FOD.

Even though I never disputed that these aerosols will impact the catalyst in a TESCR, the

quantity ofsuch aerosols entering a TESCR must be expected to be extremely small,

which means their deactivation effect will most likely be rather slow. Therefore, it can be

expected with a very high degree of confidence that the catalyst lifetime in a TESCR 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 and PYl'(}'.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 ofsulfates and pyrosulfates

takes place in-situ in significant quantities in the catalyst in a TESCR.

8. Hnrtenstein did t1(:tt discussihe recer/il Hten~ture (lin etltmlystpolsorming Sludies inBurqpc

,~t)C:itUedwith Ctl'fJri;)~ hJg31 mhH (Na $!ill<!: K) e¢'l1t~ifJin! bio~'S. -rhjs t-estifl;g h:a$ sbowed

:sjgnitk1mt J)oJsolllinS of'Catalysts due waJ!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 higher than Center lignite have successfully operated even HDSCRsU' 16. Wet

bottom boilers equipped with TESCRs have experienced no effect on catalyst

deactivation .as a result of co-firing biomass in Europell' ll.

9. Hartenstein did not off~r info:11l'tUlktn that mQre dum 20~OOOMW ofli£1initeftred unitsin

(jertl1nny wefe nQilrequired tQ iu~U SCR. in order to- coolply with the n~tonal r~'l:IJ~ti(l1l, or

that even ne\V Hgnite.:tlred units beifi~ :installed'~ rn Gernmny ,are. not eqtlipped wl~ SCR

ofany type. f~ did:I:tiQl $t~te that Oeru\1:lfiY had only one .cyc1Qn~fited botler Qper~tng with

a LDSCR (Wa!:w.nl Unit 1), Qr lhatthe unit b~s btlUt~tt}QlUsooal; nor did he advise that

VQh~rg Unit 3,a boilerin Austria firing Ii;gnile roai, ooly rail for a :short time with a high.

dust SCIt and '\\~ sub.-requently :dmtooVi'l1 and dem<J,Ushed. He Slates that TESCR

'h~\.i1fi(}IQg,y was "generally aoopted $: It univC'.rs$Uy aj}p1k..l!ble seR oolutit,)n loraH types. " ,.

'but failed to lneooon rllatlhC'~ has never been ~rTESCR il>uilt ~)e:r Sier~rf, ('which

..vas fjrtished in ~dy 1991 and has $1,lbsequentlybeen deoommisstoncd), 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!ft dtLlt OOl'tststs of'001y Qi'te p~ant ¥\Iith CeraID c~tYSt havi.ng ~l?er4'ted for ~l $~ml1

p.:;:rtou ofttrne 00 Hgnhe and afew PI~ot prosrmu:li!.l. ro that it is dl,tlJ,iQt!$ t'Q .~. tbat this v~')r

has eXI¢ijlSive ·ext'le;l'ience ~n lignite fired boflet SCRplants (see i'~)f,en.dtx A). There liIre

lrum(:rOI!J$ otheJ' i:l:\Sit!U}~$ (lifmissingoi" faetofdlyh!(~QrfeCi inf'Orm~lti'On attributed ~() Mr

H~u:'tefislein discit49sed in l'\ppendix A,

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 Bundersrepublik Deutschland, 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 of24
Due to the specifics oflignite combustion, this limit could be met by most lignite-fired

units (exceptions listed under 1. above) without the addition of SCRs. 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 statement that "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 rather than a

cyclone-fired boilerll.

The statement that "Voitsberg Unit 3, a boiler in Austria firing lignite coal, only ran for a

short time 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 of coal. 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 statement that "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 plant with

CERAM catalyst having operated for a ,short period 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 /t301e02.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 of24
equipped with CERAM catalyst and in operation for 16 years between 1990 and 2006

while the unit burned Austrian lignit~.

W. Again. the EPA fails 10 rec()gtltzecoficlusivdy thai as:!:l chemical and physical propertres of

the Texas lignite (Wrlcox h)rmattofi) that TXU propose-s t<) burn at the new Oak C'oo\>'e

p<)\verpllmt where SCR i;s beIng instaUed (but has m>t yet begun OfI'er~d:ioti) do flot repf'eseni

'\lihut lS fired in NQl1h Dakola. Jmd lheretbre tedmktU feasibiHty. ~nd expected performance II~

a TeX$ Ugnhe~fired pulverized coal :tx»ler SCiR. applic.'ll!()fi is: n<;-.ttrallsfemble to North

Dakota Hgnite~fired cydone burnet unhs: du~ to the signH'k:Mi differetlCt:S in t100 gas and ash

Chemi~a1Md pbysh;.al properties. The ~omlp'Osition ofme T~$li~ite fired ,at Marrinl,ake.

""were sen. mini~SCR p<il<:it resting has beei\ conducted, is tYp<ical t)fthe OOlnposhiQllQf

Hgnite tlred at Sa.t~... v.~d1 sodjum (t).'1de levelsin d~e Te:,'<i;"\$ Hgntteashequal to O.'']Ok The

levels ofsodiuaYi oxide in ,Center lignite average 4,4% 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 ofany

'f~lsma;t are eom~.ltble to high sodhufi NO lignite w'here 8CR installutit)n have been

mstaU~d and tested '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 if not 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 of any 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 of24
fi 1. No examples \.Vt.re rH'O'v~ded of Cl¢l~Hne e~e,lulit\~ ftlelhoos norcaialyst that would prove

res:i:stMt to dlUtlllge from $41d1meth.od$. dmt 'w(iiuld be etl'{X.·:dve in r~vitl£ $l,ii'r~e blinding

~d pore plu-~ln£ depostit$ such ~thQSe 'S;:.:m in tbeC'Oyote pilot test c~alyst ervenwhh the

:su~ed ed~e ert)s;it)ri prevMtion ~sul'e$in p'~aee. H$1s H~:rtenS;tcin d<>es not Mld:resschis

issue ttl hl:)cofi'itl'ien~ Hartenstein impHes irt hisr¢p<trt {200S). 'thatc!ttl1'1ly&t that h{l!:> been

PQl$QIJ1ed by $()dhiliill compooods .pan be l~gener~ tn",sj.u, Uifid th~ this technique i:$ \veH

devclop;ed. There ise.."<tt'emely limited experience within--situ ,cataly&t eloonin~ on c<rnl~Hr~1

units. n h$nevel' be¢rt usedr<:tr bUnded etf ehenttcaltypoisoned tatrd~~st~btJt Oft!)' t"Q1'

trtedmnleJlUy plugged catalyst {~e Appendix A}.

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 of24
discuss 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 prior to 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 what the 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 of units 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 of deactivation they do not allow any definitive conclusions

concerning the exact deactivation rate of catalyst 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, Haldor Topsoe, NOx Round Table 2007, Cincinnati,

Ohio

page 12 of24
expectation 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 of an ESP or baghouse and a wet scrubber in order to

minimize the effect ofthese fly ash particle-bound compounds. The result is a TESCR.

The biomass data provided 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 of various 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

K20 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 of alkali and alkaline earth elements in Center lignite similar to 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 presentation by 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 of24
deactivation in HDSCRs installed on units burning 100% biomass ofsimilar composition and

variability should be similar to the one of catalyst 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 of around 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 of a 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 of a HDSCR catalyst. However the rate of catalyst deactivation is

indisputably a function ofthe mass flow of catalyst 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 the Document, the

paper describes the effect of alkali 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 catalyst type

and pitch and the catalyst deactivation was mitigated by limiting the number oftimes the flue gas

inside SCR reactor went through the dew point. Both issues were already pointed out in my

report.

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

Ohio

page 14 of24
Specific Comments to the Document's Section "Results of the 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 that the 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 of a 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 in a TESCR as most water soluble sodium compounds will be removed in the

wet scrubber upstream of a TESCR and therefore are 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 of a 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, Haldor Topsoe, NOx Round Table 2007, Cincinnati,

Ohio

page 15 of24
Specific Comments to the Document's Section "Catalyst Poisoning, Blinding and Plugging"

and Applicability of SCR Development for Texas Lignite":

Again, both ofthese sections refer only to HDSCR and entirely ignores that these issues are

much less if not 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 gas but also requires very aggressive

sootblowing. Properly selected catalyst has been shown to withstand this without major erosion

damage for many 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 of various smaller SCRs Le. in waste-to-energy plantsn,g,~.

Personal conversations with plant personnel 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, Haldor Topsoe, 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 pilot testing is not needed for TESCR atMRYS while Burns & McDonnell in its

attempt to 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 consider their process 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 AlE firms disputes my claims that they have no SCR operating

experience and have never provided any SCR system or catalyst performance guarantees of any

kind.

Regeneration von Katalysatoren im Rahmen einer Kapazitatssteigemng. a presentation by Dr. JUrgen Boseke,

2008 Wildeshausener Katalysatortage, Wildeshausen, Germany

Was kann die Katalysatorregeneration zur Temperaturabsenkung beitragen?, a presentation 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 of a 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 ofthe acid gas removal system.

The waste-to-energy plants KVA Basel, Switzerland and MVA Wtirzburg, Germany may

serve as examples for this LDSCR arrangement56 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 of24
HDSCRs 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 statement is

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 of a 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 scrubber to 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 after leaving the scrubber.

In all ofthese GGHs the wet, saturated flue gases coming from the scrubber enter the GGH's

heating surfaces. Of course regular on-line washing is necessary to keep the heating surfaces

clean, which, however, is no different than 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 Bundersrepublik Deutschland, 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 of24
been 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 of equipment 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 has been 85%

regardless ofthe SOx concentration in the flue gas since 198363 • Likewise the maximum

permissible SOx outlet concentration .at the 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 of 85% even at very low SOx inlet concentrations.

Specific Comments to Appendix A "Incorrect Information"

My comments mostly address only issues that weren't addressed 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 of heat 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 or TESCR system

has a heat exchanger other than 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 of24
The author obviously misunderstood my comment about the possible elimination ofthe heat rate

penalty in case of a turbine limited unit. It is certainly correct that 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 output despite using steam for

reheating rather than having to reduce the electrical output ofthe unit as 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. After that numerous TESCRs

were retrofitted to a wide variety of combustion process including at least one unit in North

America, namely the waste-to-energy plant KMS Peel Units 1 through 5. in Mississauga, Ontario,

which has been in successful operation since 200168•

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 Henrik Noppenau, Elsam (Energie E2 until 07/0112006 ), Denmark

2. Co-firing of biomass -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 of a WTE Facility with SCR for NOx and PCDDIF

Control and Na2S4 Injection for Mercury Control", DOE Conference on SCRlSNCR, Pittsburgh, PA, 1999

22 Personal conversation with plant personnel at Evonik's Voerde Generating Station

page 21 of24
3. 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 auf die

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 Babcock Environment GmbH

page 22 of24
17. 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, Haldor Topsoe, 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://64.233.169.104/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 of24
32. 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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