-:<

NOx BEST AVAILABLE

CONTROL TECHNOLOGY

ANALYSIS STUDY

fo'

Milton R. Young Station Unit 1

Minnkota Power Cooperative, Inc.

Revised Final Report

October 2006

31777

MinnkotaPower

IMPel COOPERATIVE, INC.

YoutTouchstone Enetgy® Partner ~)\

-

NOx Best Available

Control Technology

Analysis Study

for

Milton R. Young Station Unit 1

prepared for

Minnkota Power Cooperative, Inc.

October 2006

Project No. 31777

Revised Final Report

prepared by

Burns & McDonnell Engineering Company, Inc.

Kansas City, Missouri

COPYRJGHT 2006 ,'~ BURNS & McDONNELL ENGINEERING COMPANY, INC.

:,

-- -\
I
NO, HACf Analy>i., Sludy

TABLE OF CONTENTS

TobIe ofO:mlrnlJ;

1.0

2.0

"

"

F.XJ<XUTlVr. SUMMARV.............................•••..............•...•.•..••.....•....ES-I

INTRODUCTION 1

"TOP-DOWN" NOx BACT ANAL)'51S APPROACH 2_1

STEP I -IDENTIFY ALL CONTROL TECHNOLOGlTIS__ .. . _ 2_1

STEP 2 - ELTMrNATE TEClfNICAU.Y fNfEASIBLE OPTIONS _ . 2·]

STEP J _RANK RFMAINING CONTROL TECHNOLOGlES BY CONTROL EFFECTIVENESS 2·4

STEP . EVALUATE THE MOST EFFEcnVE CONTROLS AND DOCUMENT RESULTS_ 2_5

S'I EP 5 _SELECr BACr . _ 2-6

- -,

3.0 BACT ANALYSIS for MRY STATION UNIT 1 NOx EMISSIONS 3-l

3_0_1 EMISSJON UNIT DESCRIPTION ._._._........... . _3.1

30.1 NITROGEN OXTDES EMISSION FORMATION _ >0 0> _ _ __ 3·3

3_1 IDENTIFICATION OF No-, CONTROL OPTIONS FORMILTONR. YOUNG STATION 3-3

J_ I. I REVIEW OF RETROFIT INSIALLATIONS ._ 3-4

_;.1.2 PUrI,NTIALLY FEASIBLE ~O, CUN mOL UPTiONS FOR MIl.TON R_ YOUNG STATION J-5

J.2 FEASIBILITY ANALYSIS .. _.]_6

.J 2_1 SUMMARY 01' RETROFIT INSTALLATIONS OF NO, CONTROL TECHNOLOGIES .. _..3_8

3.2_2 SUMMARY OF FEASIBLE NO, CONTROL TECHNOLOGIES FOR MRY STATION _.3-9

3.3 RANK OF TECHNICAU.Y FEASIBI.E NO, CONTROL OPTIONS DY EFFECITVENESS J-13

3.3.1 ESTABLISlIlNG DASELINE NO, EMISSIUNS FOR RANKfNG CONTROl. OPTIONS ... _._ _ 3-14

3.3.2 ESTIMATING CONTROL-EFI'ECTIVENESS OF NOx CONTROL OPTIONS .... '- ~_15

3.4 NO, CONTROLS EVALUATION AND IMPACfS ANALYSIS.. .3·20

3.4.1 NO, CONTROL ECONOMIC IMPACTS FORMRY STATION UNIT I .3·20

3_4_1_1 CAPITAL COST ESTIMATES FOR NO, CONTROL ALTERNATIVES 3.20

3_4_1_2 OPERATING AND MAINTENANCE COST ESTIMATES FOR MRY STATIONNOx CONTROLS 3-22

:1.4_1.3 I.EVELIZD TOTAL A}''NUAI. COST ESTIMAms FOR MRY STATlONNO, CONTROLS__ 3·24

3A.2 ENERGY IMPACTS 01' MRY STATION NO, CONTROLS .. .. __ '- 3·31

3.4_2.1 ENERGY IMI-'ACI'S 01' SOfA UCHNOLOGY..... _)..31

JA.12 ENERGY IMPACI'S OF SNCR TECIINOLOGY .. _ _ ._ .. .. _~·)2

J_Ll EKVIRONMENTAL IMPACI'S OF t--IO, (:ONTROl.S -MRY STATION_ : 3·~5

].4.3 I ENVIRONMENTAl.I),IJPACTS OF SOFA TECHNOLOGY __ .. J·~5

3.4.]_2 IoNVIRONMENTAI. IMPACTS OF SNell. TECHNOLOGY _ _................... 3·36

tuJ;nnk"l" P""~r-(-·""-,-,,-,,-""-,-.ll~,::- --- ------ --,,"o"c~~.,-----------n~"==.&'M=cDonndl
NO, BACT An.lysis Sludy Table ofConltnts

------- -~----

3.4.4 SUMMARY UF ECONOMIC, ENERGY AND ENVIRONMENTAL IMPACTS OFMRY STATION

NO,CONTRULS ,......... . _ " 3-37

3.5 BAC]" RECOMMENDATION AND CONTROL U,VELS _ MRY STATION UNIT I _.. _._._ _, ,3-39

3.5_1

3.'i.2

UNIT I NO, BACt"..

EMISSION RATE LIMITATION RECOMMENlJATION.. .. ...3-40

APPENDIX A ,

Technical Feasibility Assessment Details for NOx Conlrols (A1)

U.S_ Coal Cyclone NO, Reduclion Pmjects Summary and

Retrofit NO, Conlml Projects' Technical Lilerature Summary (A2)

APPENDIX B

EERC Report - Ash Impacts on SCR Cillalysl Performance (B)

APPENDIX C

Cosl Melhodology (C1)

CapTlal Cost Eslimate Delails for NOx Controls (C2)

O&M Cost Eslimate Delails for NOx Conlrols (C3)

[JU'"S & McDollnell 'lUC-2 Minnkota Powe,Cooperotivc, Inc.
NOx [IACT An,lyslS Sntdy

LIST OF TABLES

T.ble ofConlonl'

Table J-l - Unil J)e,ib'll Pammcle,:;

Table J-2 -- IhSlorieal Average Ligmte Co"1 Analysis

Tublc 3-3 __ POlc'Tlli:olly II v,"luhle NO, Conlrol Technologies Idenlified for BACT A~alysis

Table 3-4 - Idemi fled NOx Conlrol SySlcm Retrofils on Cyclone Coal-fired !loiler,

TalJ1e 3-5 - TcdLllic;llly I'eosiblc Potcnlial NOx Control Technologies for M.R. Young SllItion Cyclone

lloiters

Table 3-6 - TecImically Infeasiblc l'ot,-,~li,,1 NOx Control Technologics for M_R_ Young Station Cyclone

Boiler,

Table 3-7 - R,mhd No,. Control 0l'lion. Fea.ible for MRY Station Unit] Boilcrwilh Expected Conlrol

PerfOmltinee

T"blc 3-8 - Expeolcd Anmml NOx ConlTol Performanoe [or MRY Stalion Unit I Allernatives

Table 3-9 -Unit Capilal Cosl Faclors o[f'e:o,ible NOx Conlrol Option for MRY Slation Unit 1

TallIe 3-10 - ESlimulcu Capilal Co.ls for NOx Conlrol Alternalives -MRY Slalion Unill

Tablc 3-11 _ Estim"lcu OMI CoS< for NO, Control Allernatives - MRY Station Unil I

Table 3-12 - Eslimaled Annual Em15,iuns ,md Lcvelize{] Total Annual Cost forNOx Conlrol

Allcm"ti"",s MRY Slation !J1ll11

Table 3-13 - Dom,nnni Conlrols CO'l Cun'e Poinls for Feasible BACf NOx Ahematives - MRY Swiion

Unil I

Table 3-14 - ~~<tll1wted Emissions "ml Economic Impa~lS Summary for NOx Control Alternative.-

MRY Sl:otion Unil I

Table 3-15 -- 1i"p<:~lc,1 Au"ili~ry Iilemi~a] Power Impacts for NOx Conlrols- MRY Station Unil I

T"bk 3"16 cxpc~led Eleelrical Powcr Gencmtion Availability and Capacity Impacts for NOx Controls

- MRY .slation Unil 1

Table 3-17 -Expeoled Tolal Eleclrical Power Gencnltion Impacls for NOx Conlrols - MRY Slalion Unit

,

Table 3-18 - Summ.ry ofTop-Oown BACT Impact Analy.is ResuH, for Dominanl NOx ConlrOl

Altemalives - MRY Slalion Umt 1

Table J-19 - NOx Emis.ion Conlrol Technology and R.11e Recommended 3' BACT for Milton R. Young

S~,lion Unil 1

Tablc 3-20 -Iteeommended NO~ BACT Conlrol M~thod and 30-Day Rolling Average NOx Emission

R"IC Limit Wilhol1t SIUr1\lpS

Table 3-21 - Recommended NO, BACT Conlrol Method and 30"Day Rolling Average NOx Emission

R;'lc Limit Wilhoul Sl'rlup~

Table ]-22 - Recommended 24-llollr Rolling; Avemge NOx Emission IUlte LimilDuring Slartup'

MinnknLo Po\\"a ("onl'er:HJ"e. Ino.
NOx AACT Analysis Srudy

_._..

LIST OF FIGURES

Table ofCon\~nl>

_._--

Fl£ure 3-1 - NOx Control CO"! Effcc!iveness - MRY Station Unit J

Figurc 3-2 - MRY S1alion Unil 1 NOx Control Altcmatives Domioant Controls Cosl Curve

Appendix A1

[,igure AI-I - Pul"eri7<o(1 Coal Reburn Applioalion on Cyclone Doiler With Ovcrli", Air

Figure AI-2 - Natural Gas Rebum Applicalion On Wall-Fireu Pulverized Coal Aoilel' wilh Ovcrfire Air

Figure A. 1-3 - l-Iydrocarbnn-.enhanced ~NCR Application on PC-fired Boiler

f'lgWrc A. I-4 - Rioh Reagent Injection App] icalJon on Boiler With Overlire Air

F,gure A 1-5 - Convenlional lligh-Dusl Sc."R ArrungcIncnl wilh FGD Scrubbcr Oullet Reheal

Figure A.I-6- T,iP,a, SCR Ammgemenl

f'igur~ A.I-7 - Elcclro_Cntalylic Oxidation (ECO") Process ['low Diagram

Dum, & McDOIHldl TOC-4 MHl,1kola Power ('",opcmIive. Tno.
EXECUTIVE SUMMARY

Thc Millon R. Young Slalion ofMinnkn!ll Power Cnnperntive, Inc_ (Minnknla) and Square Bulle Electric

Conperalive (Square Bulle) indullcs lwo cyclone-furnace, lignile-fired sleam-clcctric genera ling unils

(SEGUs). The unils bOlh fiie Nnrth Daknla lignile supplied from the adjacenl mine, ncar Cenler, North

D"kol,. Unit 1 has a nominal 235 MW nCl design outpul C~p"Cily roling, is typically capable nfsustained

nUlpul ofoppro~im",cly 250 MW, (gmss), and has a gmss design nUlput capacityroting of257 MW,.

Unil 1 is owncd and opcrotcd cntirely by Minnko.La_ Unil2 has a nominal 439 MW net design nUlput

capacity mLing, is capable ofsuslaincd OUtpUI of approximatcly 460 MIN, (b'TOSS), and has a gross dcsign

oulpul capacity raling of477 MWg' Unil 2 is oWIled by Square Bulle .Electric Coopcrmivc (Square

Bullc), and Oper1l1ed by MinnkoLa.

A Nolice of Violalion (NOV) from Ihc Unilcd Slales Environmenlal Prolcclion Agency (US EPA Or

EPA) was issued La Minnkola Power Cooperalive on June 21,2002. 11,c NOV alleged thaI modifications

had been made allhe Milton R. Young Station lhat would have required a construclion permil under New

Source Review (Code ofFcdcml Regulalions 40 CrR 52.21, fill! NorthDakoln AdminiSlrative Code

NDAC 33-15). As a resull of this allegalion, a civil complaint was filed by the Unile<! Slales of America

and the Slale ofNorlh Dakota againsl Minnkota Power Cooperative Inc. ("Minnkol''') and Square Bulle

Elcclrie CoopcTdlivc ("'Square BUlte") in the Uniled Slales Districl Court for the Districl ofNorth Dakota_

A Consent Decree (CD) has been apprnvcd lhut rcprcsc'111s final ne~olialed SClllcmenl of the Uniled

Slales' and North Dakola's claims againsl Minnkotu anll Square Hulle. The ConsC"Ilt Decree requires

Minnkola and Square Butte 10 perform a "NOx Top-DoWIl Best Available Control Technology (BACT)

Analysis" to describe lhe CIlllssion limil_ for NOx that will be requued al Units 1 and 2, c;\pressed as a

30-D;IY Rolling Avcrage NOx Emission Rale [Consent Decreeparagraph 24, page 7. and paragraph 5,

p,,~e 4]_

Bums & McDonncll was n;l~incd lO conduct a Top-Down BACT Analysis for nitrogen oxides (NOx) 01

lhc Millon It. Young Stalion_ Thc results ofthe BACT analysis arc prcsmtcd in lhis sludy report.

The procedures mandated by lhe Conscnl Decrcc forpcTforming a Top-DoWIl BAC[ Analysis are

oUllined in Chapler B oflhe U_S. EPA's Ne'X.$~o_lJ~~_{~eviewWorkshop Manual: Prevention of

Sigl)ific~-'lLDeterioratlonan>! N9nallainmcnt Are" Permilting, I)rafl Oclobco 1990 ("EPA's NSR

Manual"). The MRY Sl;llion BACT analysis was perlonned in acconiance wilh lhi, procedurc. The

MiLlnkOla Power Coopcmlive, Inc. ES-l Bum.> & MeDon"dl
Executive Sununory NOx BACT Analysis Study

Ej'A 's NSR Mumml oullines nve basic slGps tbal 3rC 10 bc followL-<l in lhls BACT analysis. Thesc basil'

,tep' (or 'UGh a RAer analysi, an:: ,umrnori7ed a, follows:

Slep I -IJenlily An COLltrol TeGhnologies

Slep 2 - Eliminate Tedmictilly In[c"siblo Options

Slep ] -lbnk Remainmg Cona'ol Technologics by Control Effecl, veneS.I

Slt.l' 4 - Evaluale Mosl ElIc"Llive ContI oh and Document It..,ults

Slep 5 - Select BACT

A nest Available Control Tcchnology (BACT) an"ly,is was per[mmed for Millon R. Young Unit 2 for

NOx using the EPA's "lop-down" "ppronch. De.,t Availahle Control Techuolo~'Y i, ,ldined as "an

emiosionllimilation (including a v"iblc erni,slon <Iandord) ha""d 011 the m""imum de~'rc"" or I'edUClioll

for c""ch polJul,ml SUbJecllo regulation under Act wh"h would be cmitlerl rrom any propo"'d rn"Jor

stalionary source or m"jor mOlEfienlion which lhe IIdministrJlor, on a G"sc-by·cuoe ha,is, taking inlo

ncooonl onergy, environmenlal, and cconom;c i"'racL, and Olher CO.'I", delermines is achievable Lor ,uch

sourcc or rnoJifio" lio" Ihmugh applioalion of produotion prooesses or 'l\{uilabl" ",elhod." sy,tem" "ml

lechmques, including fuel ele,minft Of tl'eatment or innovative ruel comb"slion lcelmi'lu'" tor conITol of

.,,,oll po]]uLanl" (40 CFR 52.21, NSR ]vhTTlual R Il.

Unit I "I Milton R. Yllung SlatioLl is a cyclone-fired boile, Ih"l bums North TJnkllLa lignite. The meLhOO

offiring is very si~'lIifieuIl( TTl aTlolyzJIlg control oplions [or NOx emissions. 11 cyclone boiler produces

inherently higher uncontrolku NO, le~e1s lhan pulverized-coal and cireulaling fluiuizeJ bed boilers.

There have been no ncw ccml-buming cyelo"e-lired hoiler,; huilt and inslalled in thc Uniled SLale.' ,;ince

Ihe e~r]y 1980's. Consequenlly, Iherc nrc no clillmplcs ofBACT cunlrol opllons 1isled in lhe

RACl'lBACTfLAER Clcanllghou,e dambase for coosiueration and direct "ppliculioTl or publisbeu NOx

cmission permit limil~ On Ihc Millon R. Young eyc1one-fireu hoilers.

Slep I -lllcniify A11 Conlml Techno.loKi,~1i

The Consenl D.-cfCe requirc, Ihatthe NOx Top-Down HACT Anal)',," for the MillOn R Young Sialion

"mchlllc un eva]ualior\ or Seleotn;e Catalytic Rcduction (SCR), Selc"tivc Non·Calalytic Rcuuclion

(SNCRj, Overfire Air (OFII), Rich Re"gcnllnjeclion (RRI), a, well a< olher NOx conlru]tochl\ologlCs"

potenlially applioahle for lignile--fireJ cyclone boilen; [O)nS'"Tl1 Decree paragraph (,5, page 19]. Olh"[

identilied contmllechniques, such as [uel swilding and Iud clenTlllIg, and combuslion-relaled "rni&sion

eunlrol Icohnologic" ~uch ", f'le! I'ehnm "nd oxygm-c"Tlhanced combuslioTl, wer" "l~o coll"idered.

Dums & McDonnell ES-2 Minnkolo Power COop"'"I"'", Inc
NOx BACT Anolysis Study Ex.o<:utivo Smrun

l

,

Step 2 - Elimin~te Technically Infeasible Options

1be BAC!' evalualion dcMminc"" that nOI all the technologies idenlified were consid"",d av"ilable ond

applicable. The teohnically infeaslble altemativcs wcre e1imin.tc"" from fUTtller evaluation, along: wilh

feasible tedmologios with economic impaoL< thot were unrcasonable compared to olher cost·dliei"I!t

alternalives to control NOx emissions for MRV Station Unit 1.

The tcohnic"1 fca,ibility of applying: NOx emission reduction kehniques and leclmologics at Milton R. , Young: Stalion is dominatcd by the comp,,-,ition and combustion ~haraelerislicsof the North Dakota

lignite supplied solely from a surfac~ mine adjacent to the plant. This minc is the only supplier ofsolid

fuel for ,his slauon, "" there are no railroad faeililies pmvided to service the Millon R. Young plant.

Nonh DakoLa lignite has high moisture and high sodium content., moderate high~'r healing values. and can

have a widely variablc and high ash conteat compared to other coal,. TheSt' characteristics Crc;J le

di rliculties in promoting co",istent, sleady eomblL,tion and slag fonnation in the cyclone burners. It also

r~sullS in producing a 11yash lhat has severe deposition characteristics.

Both boilers include a unique coal comJilioning system (drying, crushing, and feeding) for each cyclone

furnaoe specifically designed to aid in proper comb uslion of!he Egnite Cuel. "Ibis method offiring solid

fuel si;:uificanlly influences the resulting nitrogen oxide eoncentration of the flue g;IScs emitted from the

boilelS.

Ash dep,,-,ition in each boiler and air prchc""",r is a significanl operational clmllengc ror the facility.

SIgnificant equipment and manpower resourecS are devoled to on·going ,emoval offireside a,h

accumuJ;,tions_ Unit outages musl be conducted at regular inlCrvals (0 clean each boilcr (appToxillllltely

every 80-120 days). Th~-rc are " numher ofi<sues that make seleetivc catalylic reduc~on (SCR)

technically infeasible for NOx emission conlrol for Milton R. Young Unit 1. The con.<;stent long-term

operotion of SCR technology on lignile-fired cyelone boilers will he draslically inhibited by lhe

susceptibility of thc SCR catalyst 10 severe fouling, deactivation, and crosion resulling from the aelions of

the emitted llue gases and llyash, and ash deposit removal operations_ SCR tl"Chnology is cornidcn""

technically infc",iblc for applicalion on the cyclone boiler1> HI thc Milton R. Young Station.

Rich Reagent Injection h"s been demonstrated on boil= buming bituminous and suhbituminous coal.

Howcvor, it has nOI bttn commercIally installed and placed in continuo", operation On a cyclone-Iired

boiler burning lignite coal with high foul ing and slag IcmperJture sC"Ilsitivilics associated and a highly

Minnlwla Power CO"P"mlive. Inc. ES-J D"ms & McDonTIcll
h,-,,"llVC SUITIffill'Y NOx BAlT ADaly,i, Sludy

variable neat comenL RRI adds ure" rc"1,,,-.,,llo Ihe hot J\Jmncc gUSe" nc,n Ihc cyclooes, which must be

devoid o[frec oXY,:cn in order 10 avoid oxidation of the urea, and Ihus erealing; NOx. While RRI is

speci flcally inlcmTcd for NOx emissions cOl\trol on cyclone boilers, RRI is considered lechnically

infeaSJhle Jor applicalion on Ihe ILgnile fired eyclune bOlkrs allhe Millon R. Young Slalion due 10 the

vurwbTc heal eontenl o[ Ihe hgnile [uel which allow, the creation ofoxygen-rich conJilions lD lhc boiler.

The uppll",,110n of'epamleu Ove, IiI e air (SOl'A) [or NUx emISsions control on Millon R. Young Unil I '~

boiler wns evaluated as p"rt of Ihe BACT imalysis. A ve,sion of.,epamled overlire air speeific"lly

designed [or increased NO, emission rcduelion pcrfomLa1\cc fOT lignilc_Grcd cyclone hOllets, referred 10

as "Advanced SOFA" in lhi.' analysis, can be ",slallcd on bolh unils nl M,R, Yo,mg Slnlion_ Tlli.'

highc,l-pc,forming form o[ SOl'A call he applied alo1\e and 1Il combination with olhc, tcchnoloeie&. Key

'''pecls o[,ucccss[ully applying "ml operating a separaled ovcrfire air sySIem on a cyclonc-fire,1 bOller

"re Ihe ab;liry to:

• AccufaIely measur~ the fuel heal ;npul rale (BTUs) ,mu cumbu,lion air inpulo Oil n real.l;me,

inul\'idu,,1 cyclone by cyclone baSl&, 10 allow Ihe ahility 10 delenmne and control the desired ,,;rfIud

ralio, especially when '",lnrvcd air' (i,e. s\lb,IOlehll)ll'Clric) eomb"sllon e01ld11101\" are I'eqlllred.

• Moinlnin at!to(lunlC mullen coal ash (,lag) fomlalion "",I now wllhin the b"rrcl, ,md ~l"g lap.,_

The degree I" which Ihe indivIdual cyclonc [urnace, e'lll he opemled w;lh lcSS_lhan_theorelical

(suh.,mic11iomell'ic) cOmbu.'lion air, whIch corresponus lu opm,llon u[ a SOl-A oy,lem, direclly

c01\!ribulcs 10 lcs, combuslion-rc1aIed NOx formati"n and furlh~r lI1-furnac~ emiBslOn redueliun but nJoo

nob ,0Ii,lifie;]lion o[ Ihe mollc"Tl e0;11 ash. This pInee, great emphasi, on achie"ing t,ghl control over Ihc

un/fud mlios on each cyclone during "ir-Slaged COmhu,lion IIp,,,alioll wilh SO!'A in order for "ir-,Iaged

eombu,tioll to be .,ucce.,sful in producing signiflcanl ,,<1,liliomll NOx c"Tl1i~sions reduclioH On lignile-fired

cycloLle hoilers.

In Ihc c"se ofMRY Stalion Unil 1', boikr, "ir-sl"ged cOmbuslion mu,l b~ ,ufficicm In reduce NO,

emissions while relea,ing enough heal 10 continue 10 rnel1lhe [lid "sh so Ih"l il fJuws dicclively wirhm

and lrom Ihc cyclone burners. Due 10 the "hmt-lelln variability ofthe combustible anu "sh eomponenLo of

Norlh Dakota hgnite ,upplied from Ihe current mine ncar CC"Tltcr, NIl, and Ihc eump1cx belm"i"f of IigLl;le

nsh when cxpo",d 10 high lemperJtmcs. Ihe ex lcol of air-slaging "nd IhtlS the level ,,]'NO, control while

operalmg the highe"I-l'erlormlng ver.<ion o[SOFA syslem IS cxpeelc-u 10 be mode'l.

Durn> & McDonnell Minnkola Power Cnnperollvc, IDe_
NO" BACT Analysis SlUdy aoon

Seleclive Non-Catalytic Rce.luclion (SNCR) lechnology has been used 10 reduoe NO" emissions,

numerous ulility boilers burning: enslern biluminous coal, midweslern bituminous coal, ancl, to a 1<

""lenl, western subhituminous coal. SNCR has aloo been used On fuel oil and natural gas-fired unil

SNCR docs not apPC-dr to be cl~l'endenl directly On 'he tyPe ofburncrs (wall-fired, langentially_fin.-d.

eyclone-Iired) employed in the boilers wh~'TC il has been ins~llled, with or wi1hout air_staged combust

with ovemre air in full operatinn_

There arc siboniIieant cOncerns associnled with elTective long_term SOFA opeHlion for Millon R. Young

Sinlion Unill 's boiler. The ability ofbasic combuslion equipment and improvements to precisely

measure lhe boiler's heal input rale in real-time on an individual cyclone by cyclone ba,is wi!b

compensation lor lhe short_term variability ofthe combuslible content of the Center lignite 10 consislenHy

muintnin Subsloiehiomelric opcmtion of every cyclone during air-Sl:lllCd combuslion is unproVCll_

Several olher lechniques and technologies were considered lechnically feasible for NO" emissions control

at MRY SLation: fuel BlClldingiSwilChing; Basic Combustion Conlrollmpro"emenLs; and varion.< forms

o[Fuei R"bum. Fuel swilehinglblencling was uOI evaluated [urlher because o[ expecled uillCasonably

high capital and operating cosLs and no addi~onalemissionreduclion compared 10 continued lignite

firing_

Othe'r NO" cmi'5ions oontrollechniquc>; "mllCohnologies JOr MRY Slalion that W~'re evaluated and

dclermined to be lechnically infeasible wcre: Fuel Cleaning; Low NOx Burners (LNE); Flue Gas

Recirculalion; Oxygen-enhanced ComhllSlion (OEC); Waler/sleam injeclion (combus~on lempering); and

Electro_Catalytic Oxidation (ECO~.

Step 3 Rank Remaining Control T",lmolo~ie~ by Control EITcclivmess

"lbe lhird slep in !be ·'Iop-down" BACT evaluation ITlnked lhe remaining control leclmoJogies by

eITecllvene:ss. Thc purposc ofranking lhc oontrol technologies was 10 eSlrlblish a hierarchy thai places at

lhe "lop" lhe control teclmology lhat achievc" the lowcsl emission level. The leclmologics in order of

lheir effectiveness, from highest 10 lowest, are, SNCR wilh ASOr-A; Gas Reburn wilh ASOFA; Lignile

Reburn with ASOFA; Fuel Lean Gas Reburn with ASOFA; ,md Advanced Sepa11l1ed OverfIrc Air

(ASOl'A). None o[lhcsc control option~ has been inslalled on a cyclonc-Iircd boilcr burning North

Oakola lignile_ A< .<nch, !hc expressed control rel'cenlages reflect the me of engineeringjudgm~"11I,bused

all lhe listed teclmique or technolob'Y applic"lion.

<-- -

Minnkola Powcr Ceoperative, Inc_ E~-5 BmIL< & McDonnell
E",,~uliy~ SmruIl"y

------_._-

NOx f1ACl' AIIaly,j, SlIlJy

Slep 4 Evaluale Mru;t Effeclive Conlrol, and DocL!rn.en!Resllh~

Addiltunal crilo,ia be,ides lechnic"l [c"sibililY were ulili7.ed for lcchnology selection in Ihis BACT

analysis. The"" included cslim"les of control effeeli,'cnc" (i.e. percent pollul"nl removed), capilalplus

upcmlmg "ml maiTLlen"nee costs, mmllalemi"t{)<\ I educlion (Ium; por yenr), e"orgy imp"els, "vc,"ge "nd

incremenlal eosl effeClivene", ($/lon), "nd environme"llial i"'paCls (olher mcdi" and cmi<sions of loxic

"",1 h"z"rdous nil' pollutant,").

The economic an"ly", exammed lhe c"pilal cosl uf ench feaSIble HACr allemativc cvnluated and any

olher powerplanl upgr;tuc cusls neee."ary 10 llnpkmCJIt lh~ allCrnallve. In addition, Ihc economic

mmly:;i:; eX311ltncd Ihe operalill!,: amI rnamLellance cost ","OGi"lerl ""tlh the highcst-perfomling form, 0L

e,ch fe",ibk RACT .llema(ive ev"llw(c,1. The,", cosL, were Ihcn eumbin~d mlO a levelized lul,,1 "nn""l

cost for" comparalive asscssmenr of Ihe lol"l irnpJ,:mOnl:llion cosl of each "ltcm"live. Finally,"s part of

the top-<!own analysis,,, durninnnl contL'Oh cost curvc w,,~ plollcd and lhe unit control COol tor each

nll~m"tjve W'S evaluated_

Two aHe,native, were on Ihe duminonl controls co,l curvc ']lid Ihu, were ;dentitied"s Ihe' mO'~ COSI

dT~etiv~ all~m'liw,. The two BACr NOx eonlrol ahernalives cv"I,,"ICd fur mcn:mcnl,1 Gosl, cncrl;y,

.mJ envlronn""nl,,I impacL' 'I,plieable to Millun R. Young .':I.tion Unil 1 were:

• ~clccllve NOr\_C,lalylic ReduclJon (SNCR) combined wllh a spec,"l fonn ofseparaled overlire

air (SOFA) specifie"lly fur lignile-lired cyclonc bUlle" (refe,red 10 as Advanceu SOFA Or

ASOI'A); and

• ASOI'A alone.

TI,e lwo ",osr c,,-,t--e[feclivc fcasible conlrol aHernallves for reduelion ofNOx cm;,~tonS werc reviewed 10

determine i L1l1c ""e or (he lecbniq ue or technulogy would r"slIll in "ny slgmfie"nl or unmna] ene'gy

penallies or benefits. Polen!i"l inerease in power planl encrgy eon.,uml'tJOLl 01' Llet genenllion rCdUe(lon."

for ASOI'A alone, or ASOFA wilh SNCR were relalively small.

The rredicted environmenl,,! lmp"GIS from implemenlalion uf Ih" lwo mO,1 eo:;(_erfecrive fe",ible NOx

emissions cuntrol "1Icm"lives from slighHy highe, unburned c"rbon in the emilled fly "sh, carhon

monox ide, and exces., ammonia (",lip") e11li&,ions was expcclc"l 10 he s"'ull ill e"'"l'ari,on wilh Ihc

Ulllns & McDonnell ES-" MilllL,,,ld Power ('''"per.live, Inc_
NOx BACT Analysis Study

-----------~--~~~-~~-

Excmtivc Summ.ry

significant anticipated reduction in far-field ozone and improvement in almospheric visibility"s a result

of lhe overall NOx emission reduclion.

Sler 5 Select BACT

Taking into ,ccollnllechnie"1 [easibihty, energy, environmenlal, amI economic imp.cts "nd other costs,

the recommended Best Available Control Technologies ~nd ussocialed emission ,--ales for nitrogen o:<idcs

emi<sions pro<!lIced by Millon R. Young Slallon Unit I boiler urc provided in lhe l.ble below.

NOx Emission Control Technology and Rate Recommended as BACT

Control Technolo and Emission Rate Recommended as BACT

12-Month Rolling Average

Unit Pollutant Control Method NOx Emission Rate

(Ibl million Btu)

Selective Non-Catalytic

, NO, Reduction with Advanoed 0.355

Sep"raled Ove,fire Air (ASOFA)

This ,""oomm""ded BACT 12-month NOx emission rale is based upon a historic pre-eonlrol 12-monlh

ba,dine "V~T"gC annu"l NOx emission rate usoo in the control amI eost-elTeclivcncss .n"lysis of 0.849

IbJmmlltu [or Unit I. The baseline emission was determined from lhe ]2 conseoulive monlh period with

lhe highest historio summation orNOx mass emissions (pounds) reported for aOlual opemlion between

Janll~ry 1,200 I and Deceml>er 31, 2005.

To complele lhe BACr delerminalion process, the Consenl Decree (CO) requires lhal '·speeific control

lechnologies to be installed and a specific Phase II 30-day Rolling Average NO" Emission Rale 1imlLation

(lbsIMMBlU)" mnst be eSlablishcd Jor each subject cmis.o;ion Unit [CD Purn~ph 66, PI: 20]. Because

there are expected to be minor short term varialions in operaling condilions where Minnkota has nol, in

faol, malerially changed any of lheir normal daily operaling praclices, a margin belween lhe 12_rnonlh

overage operaling oonditioru; and the 3lH:lay perinitlirnit is proposc-d, This reconnnended emission rale

should be suilal>ly higher such 'hat opera lion conSiSlenl wi,h the lechnologioallimiLarions, manufaclun:r's

specifiealions, and good engineering and maintenance practices 10 the exlent praeticablc for the

recOlrnnended NOx BACT allemalive would not resnh in an exceedance (violation) ofan enforceable

emission permitlimiL

Minnkola Power Cooperative, Inc. F-~-7 Bnrns & MoDonnell
beculivo Sun\ln.ry NOx UAcr Analysls Sn,dy

TI,e Consent Decree also require, Ih"l the North Dalwln Departmcnl of H~allh's (NDDI I) NO, llACr

Dclmmn"lion "~dress <pecillc emls,ion limilalions durin!; Unil SllIrtupS "I Millon R. Yoon); Sialion [CD

Paragraph 66, pg 20J. The Iype aOld ,luralion of [iriLlg during sIanup" and lhe limiled ahility of available

and fea<ihk l<"<,hnologi,,-, m cont, 01 s!.almp NOx emis",ons, bolh sip,nificanlly influCllce Ihe 30-<lay rollm);

"~~'m);~ BACT NOx emiSSIOn nlle hrnil reeomrnembl for Millon It. YOlln); SIalion hOlkTh. A 24-hour

rolling "vemgc NOx en,is.,ioo rate 1imit applJed to ,Iarlup pcriod, i, al.'o recommended for Millon RYoun); SI"lir>n hoilers_

TI,e SEGlJ slurlup opl-raling period i, usually nOI defined in emission permils. Ilowever, lor the purp{lSe

of lhis NO, fiACT analysis, Unil slarlup W"S ~efined "-, Ihe period from i~ilial fuel comhuf;lion to the

poml in lime wl,en:

• lhe measured Heat Input to lhe boiler on a 6-hourrolling average basis is greall-r lrum or ""(IU"110

2500 million BTU/hr ror IJnil I; Or

• 11,,, amount of lime reporlc"{1 for the lunge,l individmtl Uml 1 slarl0l' period durmg aoluol opera lion

belwec-n Janoary I, 20Ul and December 31, 2005 c!up,c" whichever occurs f,rst; or

• foe! filing i, discOHlirllled prior to "allSfiying ellher prcvlOus erile"a.

For MRYS Unil I, Ihe ,ecommended JO-day rolling avcr.lgc NOx em,ssion pcnnit limil r"te thai include,

Ihe impacl ofsl"T1L1I'S is hosoo upon recogni7"d operalioll"1 r;,C\OTS and eqUlpmeni designs Ihal inllucnoc

whelhel' the S~"lrtup emi"ions Tesull in higkr 30-day emissions compared t" Memal conrinuous ope, alLOll

""cludlllg .,ueh sl"rtup periods;

• Tht ""wmrolled emission ralc (i.e. wilhoul s~"P"rated 01'A or SNCR in op<Tulion) "nd ilS varinb,liIy

during operJlion from a cold >!armp up lo and including rn"ximum conlinuo", raled output;

• n,e ol'emling eondllion> Ih"l arc required 10 ~~i." lor the ,eleele,1 NOx BACT eOr\lrol leehnique;; to

bc inilinled and be cffeelive; "nd

• Thc ~ff~~livc",ess ol"lhe,e two particolar control leclllliqucs If invoked at less-lhau-MlR slc"dy-sl"lo

opera ling condilions.

• The number ofslarlups and lbeir range of typienl duration, per 3D-day perio~ limc framc.

Tbe Con,enl Deoree aud Ihe EPA', NSR Manual do UOI dc,eribc lhe method for del~TITlining a 30-{luy

Rolling Average NOx Emission Rate permil 1imilalion (CD Ph",c II) lhal reflcels BACT applied 10

MilloJl R_ Young Slalion Unit I. The approach laken in Ihis analysis W"S 10 e,lUblish a hi,lorio pre_

""nlrol 30·day hasel ine ave, age NOx emi.,-,io" rate (lbfmmBlll) from lhe 30-conscculive day penrxl with

BUIlL< & McDonOleli ES-8 Mm"ko", Power ('ooperativo, lno.
NO" BACT A'lilly,is SnLdy E"ecutivc Summ,ry

, ,--,

: t~

lhe highest historic unil NO" rna:;S cmi&;ions (pounds) rcportl-.J for octu"l operalion bctween Janua!}'

1,2001 and Dc<:cmbcrJ J, 2005. "Ibis reneels unil NO" emis.,ions thol were generated during period:; of

high unil opera lions, nol affected by unit shutdowns, stnrtups, or mnl[lInelions. This was lhen oomparC<l

10 lhe 12-monlh historic pre-conlrol baseline nveroge NO" c-mi"ion nile (lb/mmBlu) from lhe 12-

consecutive monlh pcrio<l Wilh lhe higllcsl historic unil NO" mo.,,, emissioll5 (pounds) reponc<l for actual

operation during lhe some 5-ye"r look-back period. An eSlimate ofNOx emission re<luction for Ihc

prop<lsed BACT NO" allcrnalivc opcmling nt the historic prc-conlrol JO..:]ay basdine avcmge NO"

emi.<sion rote (IblmmBtu) was mnde. This rate considered recognizod opemlional faclors and equipment

<Icsi6'11s appliC<l1o "sleady sL:lle" conditions wilh sustained output olo"e to maximum oontinuous cap"oily

ralings. The potenlial impact ofstartups, recognizing opcr<llional and lcchnicallimitations on NO"

emission conlml performance, was lhen applied to the sleady-state rate, 10 establish a recommended 30_

<lay Rolling A"croge NOx Emission Rale pcrmil limitation (CD Phase II) lhat relleoLs BACT for Ml!lon

Il. Young Slation Unil I. This is "ummarized below.

Recommended NOx BACT Control Method and

30-Day Rolling Average NOx Emission Rate Limit Without Startups

3D-day Rolling Average NOx

Unit Pollutant Control Method Emission Rate Limit

Excluding Startups

(Ib/million Btu)

ScJccLive Non-C"lalYlic

, NO, Reduclion With Advanced 0.360

Sc arakd Ovcrfire Air (ASOFA)

This rc"ornmcn~c!lBACT )O-<l~y NO" omi,.,ion role limit i" OO""d upon 0 hisloric prc-conlrol JO-<lay

ba.'eline average NOx emission rate 01'0.884 Ih/mmBlu for Unit L The baseline emission was

<Icl~TIIlincd lrom the 30-conseculive !lay period wilh Ihe highest hisooric unit NO" cmissioru role reported

for aclual operalion belween January 1,2001 and Deoember 31, 2005.

, An incrementol "djuslmenllo the proposed JO..:]ay rolling average sleady-slale unit NOx BACT emission

rate withoul slartups of0-36 IblmmBlll [or Unil 1 is re(;{)mmen<le~ for the JO-<lay rolling overage NO"

emission pennit limil period" as delined and applied 10 Millon R. Yonng Stolion. This is summarized in

the lablc below.

Minnkol. Power Cooperative, Inc. Bum, & MeDonnoll
f"""",,, 0 Summa,y

Re,'i'cd [01 17/}006

NO., rMCi.\n,L1y<1S ~'"dy

Recommended BACT 30~Day Rolling Aver~ge

NOx Emission Rate Limit and Startup Impact

JO-day Rolling Average NOx Impact Dn 3D-day Rolling

Unit Emission Rate limit Average NOx Emission Rale

Excluding Startups Limit Due to Startups

(Io/million Btu) (Ib/million Btu)

, 0.J60 +0_041 pe,,'artup

rI,i, recumlTI"nd"d adju'llTI"nt lO [he proposed JO-d"y roll ;n;; ,", e,age <ready.'tate NO, rJACT em;s:;ion

rale lLLn;, wilhLlut 'Ianup' i, !la,ed LLllOn average [,i't"';" pre-comrol NOx emission !<,,"S 0[' 0.766

lblmmDm t"or Unit 1 r~ported tor Ihe longeST individual Uni, 1 £mrtup p.riOlI <luring; ",:lu,,1 opcmtion

bolweon J;lTIuary I, 200 I ami [)o"embc, 31, l005. L'ho," "mi:;:;io"s occurred during Ihe 61_hourJune 27_

19,2005 ,lJirlup fi,r Unit 1.

A N-hollr roll;ng ;I\'omg" B,\CT NUx cm;s,ion ralo lim;l uppl;cu 10 ,Iarlup po,;"d, ;~ nl,w rccoL1\",cndcd

Cor each Lli" the Mil"m R V"ung SllIl;'''\ boiler<,

Thi, LS summarized in Ihe mble below,

Recommended 24-Hour Rolling Average

NDx Emission Rate Limit During Startups

24_hour Rolling Average NOx

Unit Emission Rate Limit

During Startups

(Ib/m;lllon Btu)

, O.')W

Thosc cmi"iulls ooomrcu dl1r;ng th" (, I-hour JULlO 27-~9, 1005 slurl\Jp ror Un;1 I,

Compli'Hloo wilh 111<,. "m;ss;on mte would De mo"slIrc<l at 11,0 staok of lhc Un;l, vo,;[,"d w;lh

CunlimLl"" Emission Moniloring; (CE,'"l) system,;n accord"nco wilh the referoncc mOlhods ,pcciliod in

40 C.F.R. Port 75, "\ld \\ 0\1 Id be uOlorminc,1 On " 30 cunsoclLt;vo Op""'ling O"y "n,1 !4·00o"",ut;,"" hour

rolling ","e"ge bn,;s, ""p~ctjvely.

[)\111lS & MdlOJlLlell ~S-l 0 ~IL"nkol" Po"e, COOp"mLLVO, 1110.
NOx BACT Analy,i, Study hoculivc Summary

A t<inl demonSltslion peri<>d of 18 month, after the completion ofCon""']]! Deoree Phase II NOx emission

reduclion syslem installalion commissioning at Millon R. Young Slation is recommcmJcd_ It is proposed

10 alluw Minnkola 10 demonstrate the aClual control sySlem capahililies oflhe combined NOx BACT

emis..,ion, reduclion sy,tem. Operating experience during the trial p<:riod will:

• oonlirm slc~dy-Slate conlrol performanoe of the combined NOx BACT emissiofis rcduelion syslem;

• allow delennination of the ability 10 further control Unit s~,rl-up emission,;

• ullow the delcrmination of the pmnilled 30-<I.y rolling average NUx emission limit including

slartups, shuldowns, and malflUlclions; and

• addres.> the specific emission limilalion, dming Unit sLartups at Millon R. Young Sl.alion ~ndlheir

impuct On the proposed )O-dny rolling uV~Tage emission role limi t (withoul startups).

Based upon the information obtained during Ihe trial period, finol emission limits can then he delerminedThe mean, thai will be employed to minimize emissions during slartup will primarily be bascd on

oper~ling procedures, holh before and after Ihe level ofupper furnaee gas lemp"ramres "ml/or heat input

rale are considered snfIiciCIlIIO "tart thc NOx controls and operating conditions are conducive for

erfeollve emissions reduction. These could be similar 10 Minnkota's current MRYS prncrices, or could be

differen~ derending upon Ihe capahilitie. of Ihe NOx control. and Iheir impoclS On Unit operations.

MinnkoLa PowerCoopcrativc, Tno_ ES-1J Burn, & MoDofiudl
-,.-
NOx BACT Analysis Study

1.0 INTRODUCTION

lntroduolion

,...

The Millon R.. Young Slalion <>fMinnkola Power Cooperalive. Ine. (Minnkola) and Square Butte Eleelric

Coopcmlive (Squnre Butte) inclmlcs lwo cyolone,furnaoe, Iignite-fired boilers prnducing slenm for

electric generalion. Bolh units lire North Dakota lignite supplied from an adjaecnt mine, near Ccnl~'T,

North Dakota.

A Notice ofViolation (NOV) from the Unitc<l Slates JOnvironmenlal Prolection Agency (US EPA or

EPA) was issued to Minnkola on June 21, 2002. The NOV alleged thal modificalions illlve been mode al

lhe Millon R. Young Slulion lbat would require a construclion permil under New Source Rcview (Cnde of

Federal Regubtions40CFRS2.21, und North Dakota Administralive Code NDAC 33-15). As a result of

lhis allegahon, a civil complaint W", filed by lhe United Slates of Amerieu and lhe Stale ofNorth Dakola

agninst Minnkota Power Cooperative Inc. ("'Minokola") and Square Butle EleClric Cooperalive ("Square

uunc'') in thc Uniled States Distriol Court for lhe District ofNurth Dakola. A Consent De=J h;1S bee'll

entered lhat rC"J,,~"SelllS a Iinal negotiated selliemenl of lhe United Slat", and North Dukola 's claims

again'l Minnkola and Squurc Bul",. The C-onsent Decree requires Minokola and Square Bulle lo perform

a NOx "Top-Down" Besl Available Control Tc"Chnology (BACT) Analysis to dcscribe the emission

limit, for NOx ibat will be required at Unils I and 2, ""pressed as a 30-D"y Rolling Average Emission

Rale (lb.<Jmillion Btu)'.

Bums & McDonnell was retained by Minnkolu 10 conduct a "Top-Down" BcstAvailable Control

T""hoolo..,!, (BACT) Analysis for nitrogen oxi,les (NOx) al lhe Millon R. Young SIStion. uunlS &

McDonnell i, n full service engineenng, architeclural, construction and environmental firm. Thc

company plans, designs nnd "onSlructs electric generaling facililies and has heen providing enVlronmenl.l1

services since !he 1970s. As port ofthosc services, Bums & McDonncll has ex",nsive experience in

permiHing-, Best Availahle Conlrol Technology (BACT) ,Iudies and control lechnology analysis. The

r"SulLs o[(he BACT analysis are presented in thi., report

IIn me Uniled StIllo, Districl Coun For The DiSlriCl OfNonh Dakom, Uniled Slates orAmerica and Siale or

Nonh Dakola, PJ,inlilf" v. Minnkotll Power Cooperslive, Inc. and Sq""re 8utle Eleclric Cooperarive, Defe"daIlls,

Civil /lclion No. \;Ofi-CV-034

'!hid -. footnule numbor t, CD pa<agr.lph 65, page 19.

Mjnnkola Power COOperalive, Inc. Burns & MeDnnnoll
Inrroducl;OJl NOx IlACT Analysi., Sru~y

Tile primary gu;Jnnce ulilize~ in prep~ralion ofnli, BACT an.ly"," i.' the U.S. EPA', New Source

Review Wor1a;hol!J0amml: Prcvenlion ofSigniILc1lnLDcterjofJliqn "IllI Nnnattainment !\rea j'ermittlng,

DrJfi. Oclober 1990' ("NSR Manunl").

In Ine next seelion oflncn·porl. Ihe appruacn 10 Ihc BACT An"lysis is de.'cribed. Folluwing Ihal, a qnick

summary or Iho pl~nl oondJ(ions "nd ,ellOr! 1>"5i, i.' given and Ihen the HACT An"lys;s h~gills. Tnc

impacl 1'0I1ion of lhe reporl is broke'1l clown inlo sq"mLt~ ,,,b,ccl;uns. Wilhllllhe lost scclion, (he re.,ul1s

01all of Ihe BACT Analysi., ,(ep", "re snmrnS!,zed fOi NOx control oplion, for Unit I'., hoiler Ollhc

Millon R. Young .%,llUn.

..__.-

, Cloap'" n on~e 1J S. EPA', New SOllre, Revlo,,!: WUTb~op Mon",]: P'!-'Vcnlion ofSigniIic"n' rkLoTj~mlio" and

NOnall";nm,nl Ar<;ca ~o-,n1(U;ng, D",~, Oc,~her l~90.

Du,n" & McDunncll

" Mirmkold P~_r C'ooperallve, Inc
NOx DACT AlJ1llysis Study 'Tn[>-Down" NOx HAC], Anal,!"i' AJlPro,ch

-------

<••,' ,..

-c'

2.0 "TOP-DOWN" NOx BACT ANALYSIS APPROACH

BeSl Av"il"bIc Conlrol Technology (BACT) is an emission, limil"lion for e~ch pollutanl from a SOurce

deLermined to he achievable u.,ing controltechnologie..,{s) Lhal provide the "maximum degree of emission

reduolion...takin~ inlo aooOunl encrb'Y, onvironmc"llt<ll. amI economio impuols'"'. A BACT review does

nol result in an emissions removal efficiency requiremenL TIle gene",lly "ccepled procedures for

performing u BACT 3n.ly~is arC oullincd in lho EPA's ,lmll NSR M<inual. The BACT annlysis for

Millon R. Young Stalion Unit I 's boiler NOx emissions was performed in accordance wilh this

procedure. The EPA'., drartNSR Manllill OUlline., five hasie Slcps thaI are to be followed in the "lopdown" BACT eVDlu"lion. These s(;.1" are", follows:

Slcp I - Idenlify All Control Technologies

Slep 2- Eliminale Technically Infeasible Option.,

Step 3 - Rank Remaining Control Technologies by Control Effecliveness

Step 4 - Evaluale Most Effeelive Controls and Documont Results

SI~1' 5 - SclecL BACT

The predefined sleps ofa BACT analysi.< are desoribed in this seelion, and resulls presented. A~ailabIc

NOx control leohniques an<llechnologies ~re defined, identified, "TId a l,cOOi,"1 deseriplion of lho

emission reduolion process and capabililies are reviewed in the following secLion_ Subsequen~y, lhose

techniques and technologies deemed feasible for retrofit applioation are ranked aooording Lo nominal NOx

controloapability_ An engineering analysis reviews the eslimated capital and operalions and mail\Lemmoe

(O&M) cosis for each feasible allemali~e, including lakin);" look at B"l"nee ofPlanL (BOP)

requiremenls. Following Ihe eOSl imp"el <!elc"TTTlinalion, lhe energy and environmenlul ilIlJl'lel' "re

reviewed for e"oh feasible leehnology. :Finally, lhe re,ulls oflhe engineering analyses are tabulaled and a

NOx BACT selection is recommended for each unil_

2.1 STEP 1 -IDENTIFY ALL CONTROL TECHNOLOGIES

'lbe fir,t step in a "top-down" NOx BACT analySis is 10 idenlify, for lhe emissions unil in quesLion, a

comprehensive list ofall "available" comro] oplions_ In tho EPA's draft NSR Manual,

"available conlrol oplions are those air poilulion eontroll<:cOOologies Or leohniques "'ilh a

practical potenlial for applicalion to !he emissions \mil an<llhe regulated pollulant under

evalualion. Air pollution conlrOllcchnologies and techniques include lhe applioalion of

• Ibid f""tnole numbCT 2, NSR Manu"1 8.1

Minnkoro Power Coope"Ulve, IllC. ,-, Bum' & MeDonndl
"Top-Du\YJl" NOx RArr An,lysis Approach NOx BACT Anolysis Slu~y

produclion proccss or avaibhle methods, sy,tems, a~d IcdllliqllCS, indwJing hid cleaning

or treatmeLlI or "lno~ali~c fucl combustion teGhniques for cOlllro] ot-the allecled

pUlllll"nl"'.

According 10 the EI'A's draft NSR Ma"u"l, "" IcchnoJugy is considered "available" if II can he ohl"incd

by lhe aprl icant throlJgh oommcrcwl channels or is olhetwi<e avnilnbJo wilhio the COmmon seruc

"'",ming ofthe lerm"'. AI,o, "a cOlltlOltechni'lll~ ii; ~onoi,kITd "vaiJablc, wilhm Ihc conlext pre,e~lcd

above, Lf it has reached Ihe l;cen.,iJ\g and commcrGwl sales stage ofdevelopment"'.

In ord~r lO idenlify ov,,,bblc NOx cmissioll cOlltJOltechnolot~j~, oml lcchni(lU~' appropriole for polenli"I

"pplic"lion to MIlY Slalion units, the followintl inforrn~llOn sources were reviewl"<1 for coal-lired clcclne

genera ling unil powerplanl<:

• EPA's RACT/llACT/I.AER Clcunnghouse (llBLC) daLaMSC and Control Tttlm"lugy Ccnter

(w<ob"l").

• Federal (EPA) and State, including North Dakot" Department of Healih inlerne, "eb,iLes roc air

emis.,ion reI mil, and recentl y-suhmilleJ applicalion" iLlciuding BACT Evalualions [ollu"Iing

New Source Re\'i~w p"x~d"rc".

• fcdernl (EI'A and Departmem ofJuslicc) and SI"le, including North Dakola Deparrmenl 0[

Heallh inlernet websile.' lor COrl,ent Deerecs ""ued as a result of legal aclion.< laken hy lhc

Uniled State, governmenl ror alleged violallons ofthe Prev~ntion of Sig"; [icanl Dclcriomlion

(PSD) provi~iuno ,m,l Ncw Source Review pl'Ov;,ions uf Ih~ Clc"n A,r ACl, ;m,Vor federally_

;Jppwvcd ,md enfurccable Slale lmplemenlalion Plans.

• Conh-ol lechnology vendm in lornl3lion.

• Pohli"hed and .vailnhle in formuliun from lechlllcal, cngineering, and envlronmenl,,1 consulIanlS.

• Teehnie;J1 lilewlllfC found In journals, report" inlernel w~b,il~", nc\v,lcllcTS, proceeding., 0 r

techmcal seminar, n"d oonli:renecs pcrlaining 10 "tudie" engince'illg, de.,igns, and le,ling ofair

poj]lllion conlrob.

'Ibid, NSR Manual R_5

" Ibid, NSR Manual B.17

'Ibid, NSR Manual 8_1~

Hum, & McDonucll
NOx DACf Analysis Study "Top-Down"NOxDACf Analysi, Approach

2.2 STEP 2 - ELIMINATE TECHNICALLY INFEASIBLE OPTIONS

The sc""ond slep of lhe "lop-down" I:IACr process is 10 evaluale lhe available NO" conlrol technnlogics

and techniques ilkntific<l in SI~1' 1 in lcnru; of Ihe ,pccifi~ fa~lors thaI apply 10 lhe emi"ions unit in

qucslion. In accordance wilh EPA', draft NSR Manual, "an available lechnology is "applicable" jfit Can

be re"-,onably in,talled amI opera led un Ihe suurce lype und~T cunsidemtion. A lcchnology lhat is

av~llnbk un<l upplicable is tedmically feasihle'''.

The EPA's NSR Manuul ,wlcs a technology rnJy be determined 10 be not applicable if"a lechnical

~:;sessmcnl eon'idering physical. chemical and engineering principles andlor empirioa] data showin!; thc

technology would not work on the emissions unil under review Or lhat unsolvable le~hnical difficullies

would preclude Ihe successful deploymenL of'he teclmique"'. A1so, a "showing ofunrcwlvnble l"ehnieal

difficulty with applying rhe conlrol would con,litule u showin!; of lechnicJI infeasibilily (e.g., sire of lhe

unil, locarion of the proposed sile, Jnd opera ling problems relaled to specific eircumswnces of the

source)"". Allcr a del~"ITllin"lion i, made lhat any of lhe processes are technically inf""sible. option:; arc

eliminated iftechnical challenges would preclude or prevent the suco=ful long-tenn use ofthe control

optioo or lechnique On lhc cmi:>SlOn unil under consider"lion. This is perfonned prior to any economic

analysis.

However, the £1'A's NSR Manual also Mates"_..control oplion:; in"-llpablc ofmccling an "pplioable New

Source I'erfonnance SLandard (NSPS) or SlaLe Implementalion Plan (SIP) limit would nol mcellhe

delloilion ofBACT undcr any circumslanocs. Thc applioanl does nol need 10 consider !hem in lhe BACT

an~lysis"". Also, il slatcs "An NSPS simply defines lhe minimum level of control 10 be considered in the

BACT "n"lysis"". The NSR Manual further slales "When developing a lisl of po.'SJble BACT

alternatives. lhe only reason for comparing control oplions lo an NSPS i, [0 clclcrm;nc whClhcT the conlrol

oplion wOlild re:;ult in un l'TIlission level less stringenl limn lhe NSPS. Ifso. the oplion is unaccepLablc"".

New Source P.rfonnance Standards (NSPS) lor NOx emissioos from EGU:; firing Nonh Dakma lignite

are o.~ lb/mmBtu. The EPA Acid Rain Program's Tidc IV No", emission limil for Group 2, cyclone--

fired conI boilers wilh oUlpul' greatcr than 155 MWe is 0_86 Ih/mmBtu.

, Ibid, NSR Manual B.17

'Ibid, NSR M.nnal 8.20

" Ibid, NSR Manual B.19

lL Ibid, NSR Manual B.12

" Ibid, NSR M.nnal B_12

" Ibid, NSR M.nu"l B. 12

Min""OI' Po"",r Coo~eralive, loc_ Burns & McDonocll
"Top-Dmm" NOx DACT Analysi' App""'ch NUx BACT An.lysi, Study

EPA'.\ deafI N»R Manual 0100 sinks"A source would not be requircdlo CXp~Til'll"C edended Lime <lelay.,

or resource p,:n3Il,es [0 allow r,,-,em-ch 10 be conducted On n new Le<ohnique. Neither's il expeclcd thai an

npplic8ll1 wnnld be requireulo cxperience txlenclerJ j, iat, 10 learn how to apply" l~chnologyOll 0 lol~lly

new and dLs3imil"r sourc~ Iype. Co",equenl1y, technologic, in the pilol ,""le IL"l,ling SLa.~es of

<levclopm~nt would nol be considered available for BACT rev,ew""-

Al,o in Lhe EPA's draft N»R M"nu"l is" <],,,,li/iealion for leehnical feasibility, as de,m!:J<',1 by lht:

stalemenl ·'Commercial availabil,ty by ilself, howcver. i:; nOI necessarily a snflicieLlI ba3is for concluding

a technology 10 be "pplieahle and therelole technically [ca"bk. Teehnic.l fc"Sibllily, a, de1ermined in

Slep 2, also means a conlrul oplion may reasonahly he deployed on or "applicable" 10 Ihe source IYpe

'mdcr comide' aIJOn"".

2.3 STEP 3 - RANK REMAINING CONTROL TECHNOLOGIES BY CONTROL

EFFECTIVENESS

Thc lhird SICp in Lhe ·'lop-down" HACT ev"luation i:; to rank Ihe oontrol lechnologies rcrn"ining "ncr the

fe"sibility "n"ly~i., by control efleclivene.". The p lIrpo,c or'rrmki"f: Lhe conlrol Iechnologies is 10

e'ta]'l"h a hierarchy lhal "pl~ecs;J( Ihe ·'IOp", Lh" comrol teelulOJogy th"l achieves Ih<: lowcsl emissi(lll

level"".

~eJeeling commO" unil< in order to compare emlSSlOns pcrfonn"n"~ level, amongSI opIion3 i3 one of Ihe

Lwo key is..,"es Ihat musl b~ addICsscd in a BACT analy3ls. EPA', draft N~R Man"al ,1"les "il is

generally mosl cJTcClivc 10 e~pICSS cmis,ions performance as"n average ,tcady sl"tc cmi6,;ons l~vd p'"

1mil uf producl produced or proce~:;G<J"", For fo%il fuel-lired boilers, ponnds ofllllrogen o~idc, pcr "lllt

offuel hcal ;npul (Le. lblrnmnruj, is a common means of "ump"ri"g ""d CO!cuIOli"g NUx emis31Ons_

Mnny eontrolledmi'lucs, including both "dd-on "o"twl, ""d inherenlly lower polluling pro"C"'"S CUll

perfonn "I a wille range onevels. The EPA'3 deafI NSR Manual ,Iulc:; ·'Il is nol lhc EPA', intention IO

,equire an"lysis or e"ch po,",ihle level of efficiency for a conlrol techniqot:, as s""h 3n analysi., would

" Ibid, NSR M"nu.l B_1 S

IS Ibiu, NSR M"'mal B. IS

"Ibid, NSR Manual B.25

"Ibid, NSfl Manual B.ll

Burn, & McDonndl M;JlJ,kola PO""" r:nnp<mli~c, Inc.
NOx BACT Analysis Siudy "Top-DoWII"NOx BJ\Cr Analysis Approaoh

resull in a 11lJgc number of oplions"". Also, "[lliInufaelurer's dala, engineering eslimateS, and lhe

C};pericnee ofolher Sources provide the bas's for dcl~TITlining achievable limits"".

2.4 STEP 4- EVALUATE THE MOST EFFECTIVE CONTROLS AND

DOCUMENT RESULTS

'fhe [ourlh Slep ofa "lop-down" BACI' re~ie"" " to evnlt", Ie (he lechmcally-feasible emission controls,

begilming wilh lhe moSI effective. Economic, energy, and environmenLal impacts are 10 be assessed and

quanli r.ed, where possible, in Lhe oonlrol teohnology analysis. The purpose o[ Lhe evalualion is to

dclcTITline iflhere are any idenlified impaotS (hal wonld eliminate lhe top control technology from

consideration. 1n the case where the mosl cffeeLive control ultcmalive is detennined 10 incur or produce

adverse encrb'Y, economic or environmentnl iITflacl", Lhe ba,i, of Lhe determination is doeumenled, and

lhe next mosl stringenl control allernative is evalualed. TIlis analysis process cona'mes untillh~ eonLrol

leehnology under eonsidemlion cannOI be eliminaled by idenlification of "oIl' ""uree_speoifie advers.

energy, economic or environmental impacL'.

The economic impuclS are ba'ed on estllllilles ofeap;ral equipmcnl prioing, procuremen~ imaalla tion and

estimoted opera ling and mainlenancc COSts. The lotal inslalled capilal eo,IS along with the opera ling COSlS

[or ~.,.ch controllechnology arc summarized in the economics of each respeolivc >;cclion. The Levelized

Total Annual COSI (tTAC) represenls lhe levclized cost ofprocurement., construolion, operalion and

mainlenauee over an assumed service life. CoSl effecliveness ($/lon) of a controllechniquc Or technology

lS calculated by dividmg lhe LTAC ($Iyr) by lh~ unnlUll amounl ofNOx removed (lnmJyr). Baschnc pre_

control "missions are ealclllal~d using reali.'llc upper bunndary opera ling assumptiOnS, considering

inherenl physical or operational eonslr.inlS on the source. Plotting ofthe annual amoun! orNOx removed

(lonslyr) ven;nS the levelized tolal ,,"nunl eonlrol co.,t ($!yr) [Or the various control options on an x_y

b'f"dph anows visualizalion of l\l~ cosl-effeoliveness. A "leasl--co'l envelope" can be readily identific-d lO

indicate the inferior control oplions which ,hould nO! be considered in lhe subsequent analyses. TI,e

incremenlal cosl--e[[ecliveness (difference in $Iton) bcrween oonrroltechniques or lechnologies eM also

be euloulaled and compared. This allows evalnalion o[ ibe dominant controls includcd on the leasl-<oost

envelope (curve).

LB tbid, NSR Manual D.2J

"tbili, NSR Manual ll.24

Minnkol" Power Cooperdlive., Inc. ,., llums & MeDnnIlCll
',np-Down" NOx DACT An.Jy_';' Approach

2.5 STEP 5 - SELECT BACT

NOx BACT AnolyslS Srudy

The f,nal slep in lhe '<top-down" eVUluaIion process is 10 ,dcclllACT for Ihe applie~blc pollulant and

emission unit. Per lhe EPA gUJdallee llocomell~ BACT i, "Ihe mo,1 dkclive eonh-o]ledmology not

ellmin:JkJ in Stell 4'''"' The mclhodology JC"~TlbcJ above was applied to Ihe Millon It. Young S10llUn

Unil I'Rboiler for enmsions ofnllrogcn oxide"_

_c_

ll"rJl5 & McDoTIndl 2-6 MinnkoLO Powel Cooperative, Jnc,
NOx BACT Analysis Study llACT A~alysis for MRY Slauon Unil J NOx Emissions

3.0 BACT ANALYSIS for MRY STATION UNIT 1 NOx EMISSIONS

The approach laken in Ihis BAcr analysis for Milton It. Yotlng Station included a technioal analysisof

demOnSIT1l1cd conlrolaHemalives for NOx emissions. This upproaoh followed the predefined slep.s of a

BACr analysis process as gcncrully dcscribed in Section 2. POlential NOx control techniques and

leehTlolo,~ies W"!'C idenlified, and a leehnical dcscription of1he emission roouclion prooess and

capJ bib' lies were provi<k:d. SIlb6equcn dy, lho~e techniques and lcchnologies deemed available and

feasible for re1rofilapplicalion were ranked according to nominal NOx control capability. The

enginecring unalysis 'hen developed the ,,",tima1ed c"pitJI and O&M costs for each aHemalive. including

taking a look al Babncc orPlanl (HOP) rcquirements. FinJlJY,!hc oosl effOClivoness poinls for each

feJSible leclmology werc plolted, and !hose thul comprise lhe domimml controls curve werC identificd.

for the feasihle lechniques and lechnologies considcred for deten-nining NOx control cost-effectiveness

for thc two steam cleolrio generating unil' at the MilY Slalion, CSI;mates were produced for predioled

NOx n::d"olions Ihal represent aohievahle long-term expectalions of the alternal,ve reduction techniques

and lechnologies being- prcsCillcd in lhe tc"Chnicnl analy,i.. Each wCTC lubulatcd and gnphed.

3.0.1 EMISSION UNIT DESCRIPTION

MiHon'R. Young Stalion Unil I is owncd Jml opcmled enlirely by Minnkota_ MRY Station Unit 1

includcs a Bahoock and Wilcox sleam genenlor installed in 1970_ The slearn generator is a lignile-fired

boilcr with mulriple cydolle-fuffiaoes installed in parallel using bDlanced-drar, and natnral circulalion.

Original unil 'lcsil,'Tl steam generating capacity is 1.714 million Ibslhr ut 1,920 psi Wilh Dfuel heal inpul of

2,510 mmBlnfhr. The boiler is fired by seven ten-foot diameler cyclone burners. arranged ··thrcc over

four" ucros< lhe front wall of lhe lower furnace_ Thc unit has a tnhular air healer ,n,lalled between lhe

boiler amI lhe flue gas ductwork lead,ng 10 the electrostalic prccipilaLor (ESP)_ Exhaust gases leave Lhe

air heater and pass lhrough an ESP for pm1iculalc collection and removal prior to Lhe lWO induced dron

fang (installed in parallel) which discharge 10 the stack. Unill has a nominal 235 MW nel design output

eapacily raling, is typically capable ofsu.,tained outpul ofapproximalely 253 MW gross, and has an

uHimale shorHerm maximum gross output (URGE) rJling of278 MW_

Mitmko!a rower Coopernllvc. Inc Burns & McDorulell
BACT An,ly<i., r", MRY Sialion Unill NO, Emissions NO, R/ICT Analy<i, Sludy

The EPA's Tcchnical Snpport Ooc"mcnl"' puhliHhed in the E<lockcl (EPA', ;nlCmcl website) lor t1lc

Filllli BART Guiddines li,t" nnmeplale slcnmlurbinc-~cneralorcapacity of MRY Slalion Unil I as 257

MW fgros,), which W:Of; a,sumcrl for calcnlating capItal cost cslimalos [0' control al tel'llaliw,.

Tilo Unil 1 borle, at M.R. Yonng SI"lion ;nd"rlcs a umg"e cu"l cumlillUnin~ 'yslem (drying, "rlIshing,

and feeding) for each cyclone furnace spc"ific"lIy designed 10 ald in proper coml""lion of the lig" ile Iud.

n,is rTlClhou offiring solid fnel sit,nilicantly inlluence, Ihe rcsuhlll]< nilrop,cn oxide conoe"lrJllOn of Ihe

fille g<tses emliled from Ik boiler,;.

Milton R. Y olJn!~ SI"lion Un;1 I'R hoikr <lcsign, combuslion performance, and NOx emissions are

dOJ1lin"l~d by Ihc compo"i,ion an,1 ~ombu,tion chnraclcrlSl1C, of lire North D;,kota ligLl ilC sOJpplic-.:l solely

frum" surface mine adjncenl10 lhc plant. Tni& mino is Ihe only sopplicr ofsolid fuel for Ihia sl"lion, as

Ihcre are no railroad facilili~s provided 10 sCTvicc thc Millon Ie. Young plant Norlh Dokota hgnite ha<

high moisture amI high so<1ium conlenl, moucrJle higher healing values, and tnn hove a widely variablc

anJ high ",h eonlc-nl compared 10 olher coals. The.,e oharnclCri,llc, create difIiculties in promolin>:

eon,islc-nl, slcauy comhu."jon nnd ,lag formation in ll,c cyclone' bomcn.. II also rerullS in prmlucing a

TIyash lhal has ReVere <1ep"'ition char aClcrislies.

TI,e de,ign urnl upcraling condi'ion, for Ihis study are pre,eTlled in Table 1·1. 'J he hislorioal avcnl!o'C

li!o'T1llc cool nnnly", i, shown in T;lble ]-2.

Table 3-1 - Unil Design Parameters

Unill

lksi nllnilO Cr~liJlu Ch~raclec;sfks Do,; Il

noiler Type Sllbcriu"I'"

O)mb\lSI;On Sy'lem Cyclone

Number of Cyclnne,; '"aJlgemL"1l~ localion 7; J over4, lmnt

ULlil DOSlgn Cap,eity Eleclric.1 Ou \II''', MW (neL!~r",,) 2)5/257

(I) Bal,neod drafl singIe dIUIll, ,uPerhealed 'learn wilh .,in~k .,",gc o[.,loarn Ieheal.

(2) The,c values Wtre eslabhshed hy Ihe original ct]wpmcnt TrulnuL.oluror.<, r,ior 10 Con>lruo[ion.

" EPA Dockel OAR-2002-0076-0446 Technio.1 Suprort Doc"lTlOfil [or BART NOx Limil' for Eleclric Genomting

Units £~Ld Sprcuilihccl (,11512005, pO,led 011 their we!>-,ile: [Will EDOCKEr ot

hllp-ffdockeLeI'•.gov/cdkpuhidolEDKslamternDo10ilView'!obj ecild~O'lOOO 7d4 80M562b; Ihis l' OSSO' ialoo wilh

EPA Aoid fuoin Progr-"rn C1e," Air M"rkel> Divi'ion, Technical Support DocuIDenl- Melhod010~y Jour Developing

DART NO, Presu"'pli,'e LimilS, June 15, 2005, OAR_2002-0076_0445

" Ibid, fOOlllOle number 2, NSR MOIl"al p,~e B.ll

Bum' & MclJo"ndl 3-2 Minnkola P"WIT Cooporalive, Inc.
NOx BACf Anal}$is Sn>Jy BAer Analysis ror MRY S,allon Unit I NOx Emi"ion'

3,0.2

Table 3-2 - Historical Average lignite Coal Analysis

Lignitc - Ccoler Mine A~er.ge

UJiitnale Coal Analysis: ("-, leceivcd) %l> IlIaSS

Moisturc 37,29

Carl>on 38,69

Hydrogen 2.50

Nilrogen 0.57

Sulfur 0.81

~" B,74

Oxygen ll.40

Total 100.00

Highor f10aling Value, Dlu/lb 6,662

NITROGEN OXIDES EMISSION FORMATION

Nitrogen oxides (NO)!) arc produced when nitrogen TIl the fuel and eombuslion air an: exposed to high

lemperature!;. There are lwo prima ry sources ofNOx emissions, referred 10 a.< '1henrnl" NO)! and "fuel"

NOx . Thermal NOx emissions ~re pm<!uood when elemen~,l nitrogen in Ihe "ombUSlion air i' udmilled 10

a high lempe' alUl e zOlJe alkl oxidi«ed. Fuel NOx emissions arc ol"C"dled d~ring Ihe rapid oxidalion of lhe

fwel containing n ilrogcn compounds_ For m(}.';t coaJ_lired unils. Ihennni NOx emission lypically

rcpresenls a pproxillliliely 20"10 and fucl NOx about 80% of Ihc 101,1 NOx formcd_ Nitrogen oxidc (NO) is

lypically the mosl prcdomi".nl form of NOx emissions from fossil fllel combuSlion. ,long wilh nitrogen

d 'oxidc (NO,J_ "fhc fomJation ofthesc compounds in ulility powerplJnI boilers is sensitive 10 lhe melhod

offiring and combuslion controls utili·led. The lechniQues employcd for m,xing Ihc combusllon air and

fuel. which creales flames "nd high lempcrnture combuslion products, resulls from Ihc rapid oxidizalion

of carbon. hydrogen, and olher exolhennic rcactions_ Cyclone-lire<! boilers, by design. ereatc inlensc hcat

",le;,se rales 10 mell "nd fluidize Ihe co"l ash introduced inlo thc barrel-shaped furnaces. This produces

high lemperarure flue gases and ",sulls in very high uncontrolled NOx emissions. TJ,e amounl oflhennal

NOx emissions produced by cyclone boilers can be consid"'<lbly highcr Ihan fuel NO)! emissions.

3.1 IDENTIFICATION OF NOx CONTROL OPTIONS FOR MILTON R. YOUNG

STATION

Thc first step in lile MCf eva! nstion is to identiJ» sll "dernonstr:lted and polenlinlly applicnble control

leehnology allernatives"" ,ccording 10 lhe EPA's draft NSR Mannal. In identiJYing control lechnologies.

"lhe applicant needs to survey Ihe r.rnge ofpotenlially "vailable control oplions'""'.

,. Ibid. NSR Manual page B.11

MinllkQI. Power Cooperative. Inc. Burns & McDunneil
NOJe BACT Analysis SJlldy

3.1.1 REVIEW OF RETROFIT INSTALLATIONS

The BACT Jelennina,ion~ li,le<l ill the ~.P A', HACTITIA(:T/LAf'.lt C!eal'inp,house (RB1.C) dalabase arc

f<1r new faeililies. The Millon R. Young Sl<l\ion i~ 0" "",,isling powerpl"1\l beilil)' with lWO coal_fired

HJUs. A BACT ev"lunhon for retrofilling control equipHIL"l't 10 c""l-[ire,l i:GlJ, in an c""ling facili,y

will be sub,lalllially dl ffc'un lhan on all"ly,;i, for in,lallinfl comrol c(luipmenl on ooal·[ired EGlh LLl a

new lJcility. Con,equ""tly, in po['fo'mmg the BACT "nuly,i, for exi,linR boiler, al MIllOn It. YounR

Sialion, il is imporlant lo l'C"iew pO\>lerpbnt f"cililic'", ~speeiolly eydnne-nred coul hoilers, whioh ha'"

rell olitled NOx eornroI e()uip ment in recent yea".

In 1998, EPA "sued a No" 311' (Slale lmplemc"l'l,,,ioJll'lan) calL UndEr the SIP c"n, Hlilily boiler, illlhc

",a'iem Uniled Siale, were required to sllbslantially redute NOx emi"ion' during lhe "owne ,eaSOn"_

'11", tomplianco wle l'or Ihe NUx SIP tall is "'by 31, 2004. l\. h;flh pcrt~nlage of the fIT"" eketri~

generation ["ellilies in Ihe ~~slem Uniled 3Iale., have or ~re in lhe luoce" o[rcllolitling NOx eOlllrob to

comply wilh lhc NO~ SIP c"ll. The ErA's NO" Slt' call was nal aj1plLcahle 10 North Dakol" ulility

boilers.

There "re a numbcr o'fossil fuel-LLred EGU powerplams around the lJniled Siale, tllatl""e imp1emente<1

or arc planning 10 ill1p lemenl modificalions to reduce NUx emi"i"n,. The NUx em;"ion control syslem ".'

installalions are in r~sponse lo ACId Itain rc-quiremenL,. EPA', NOx SIP cun, il,e Clean AIr IDler~lale

Rule (CAlR), the Regional Hazt Rule (lll-m), und local regululioll'_

In addilion lu Ihe [aeililie, lha' have h"d 10 r",lrolil emi"'iOTI' controls"" a rcwll of lheTitlc IV Pun 7(,

Ao;d Rain L'CquiremenLs and/or c1'A', NOx SIP call, a few inslullahons ll"vc had l" retrofit conlrol, in

recent yLllrS as Ihe res\llL ofCO\llt deci,ions resulting Itom liliRa tion "nd ":gul~lory aclion. None of lhe

boile" a"ocLaled Wilh idenlilied cunsenl de~r"cs are oyc1one_rned. They urc abo localcd in u region

requiring oompliance Wilh an EPA-Jpprovcd Slate lmplemen tati on Plan [or nitrogen oxides emi.,ions

control> (i_e. NOx SIP c"n). lis menl;one,l abow, Norlh Dakota uliliIY boiler' were nol ,utricct 10 lhe

EPA'~ NO" SIT' calL

.,-4 MinnkOU1 Power Coopcra Live, Inc-
NOlI BACT Analysis Study BAcr Aoalysis rOT MRY Sr:uion Unit 1 NOx Emission'

3.1.2 POTENTIALLY FEASIBLE NOx CONTROL OPTIONS FOR MILTON R.

YOUNG STATION

A review of a\'ailahle infoTTIl"(ion On relrofil imtall"lions pcrfOmled at utilily unci ind"'trinl cool·fircd

powerplo.nts during the ]XISl fifteen years was undcnaken. NUx emission control lechnologies and

lechni'1oes Wilh pnlenli"l "ppli~aljon lO M Llton R. Young SlUtion boilers were identified. and ar~ listed in

Tahle3-3.

TABLE 3·3 - Potentially Available NOx Control Technologies Identified

for BACT Analysis

NOx Control Tctohnology

Pre-CombuXlion Controlx

Fuel CleaningIBlendinglSwilching

Combustion Conlrols

Basic Comhu'lion Conlrollmprovemenls

LowNOx Burners (LND)

Sg>araled Overfire AiT (SOFA)O) -

Flue Gas Recirculation

Fuel Rebum

-- Oxygen_enhanced combuslioo (OEC)

Walerlsle,m injecl;on (combustion lempering)

Post_CamburtioD Coutrols

Sdeclive Nan_Calalytic Re<1uclion (SNCR)

Seloolivc Catalylic Reduclion (SCR)

El~lra-Colalyric Oxidatioo (EeO )

NoleS; , >< ,. c rom", orlhe idenLiHed [ocho; ucs. he"'" b" q No' all ,ariaMo, or combin,lion' ",e induded.

(I) - SOFA technologies inelude Boosted SOFA aod RutaL;ng Opposed firotl Ai, (ROFA)

(2) - SNCR lechnologie, ;nolude Rich Reagoo, Jnj,euon, 'nd Hyd,ocarbon.""h,n=l SNCR.

eOJnOl"re,oJly avail ahlo .. "NO.Sl "Thi,..

(1) - Mulli_polluLaIlL con'rol'echnology currcnlly nuver commercial develop""nL hy rowerspao Corp.

A compTchensive lile"'lurc sC"Tch, with sources induding le~hnic"l papers and present'lions mode a\

confercn~es by nationally-reoognizc<l technical organi?.ations. utilities and olher ]XIrties involved with

design, oonstruclion. and lesting ofNOx ~ontrollechniqu"", plus hardw<lTe supplier cl<pcricncc li,IS, was

pc,fOTTIled. TI,e Tesulls oflhis search are presenled in Appendix A2, which indudes a summary of

various selecled U_S. NOx emission TccluClioll TClrolil projects.

Minnkola Powu C'.oQpcrnLivc, Inc. Durns & McD<:mneU
BAIT An,lyslS [or MRY S'a,ion Uni' l NO" Emission'

3.2 FEASIBILITY ANALYSrS

NOK BACT An,ly.,i, Srudy

TILe second &lep of Ih~ "lop-<lown~ BACT rroce" i.' 10 ev"lt"Jk Ihe control rroce""es that ha"l' bcm

identined and delel'lni"e iI' a"y or lh~ processe' arc lechmeally inf"",ibk,

An availahle leehnology is "applicahlc" If 11 ~"n be rc",onably bc imlulk<J 'lnd opemlcd on the soure~

lyp~ "ndlT ~ons](krJtion. Also," conlrol lechnique i.' considered available if il has' each",l Ihc 'lage of

licensing and commercial avmlabil;IJI. For lhe purpos~s o[ lhi, aMlysis, the ,erm "wmmercial" is further

defined to mean "capahle ofe,tahli,hlllj{" [,,11 cOnln,"I",,1 a~'IT<mcnl wilh "ommcrci"1 nnd perrO! mance

!\uaraTl'ee.' snl'pnrted hy apPnJpriul~ limn"ial backing" for Ihe J1nl'lemcn~'lion offulk"ale, tull-,im~

oyolemS of'he leehnig"e or tc"hnology applic"lion. A technology Ihal is availablc and "pplieablc i,

Icchni""lly fcusibk.

There are lhree basie cale~orje" ofNOx emission ~ontrol leclmiqucs und t~chn(ll(l8ics;

• Pre-comhus'ion conlrOh;

• Combuslion conlrols; and

• Po.,t-comhuSIion controls

Uncontrolled NOx cmi"ions from a coal-fired electric tL"!lcl1,ling unit al'e hJghly del,endeol OOlype of

firing meIhod, amonnt ofsolid fuel Iired per "nil lime and furnace volume, nmllh~ fuel's basic

comhmljon propenie._ and elemenlill oomposilion. The basic melhod, [or rcducliuu ofsuch emi""ioos;

• ei'her pLevenl p"llUlio", i.e- "'C inhcrL"Illly ]ower--emitting procc",cslpmclices wluch pr(lllucc

[ewer NOx emissions durjn~ the [l<lwer g",,~r,llion prucess; Or

• involve improvemenls 10, 01' pmvide new add-nu coutrols IhM, reduce emiSoions nfier lhey are

prodnced hefore lhey are emi'l<:,l from lhc fncility; or

• are combiillliious ofil1heremly lower--emilling proC""'"" al1d add-on controls.

MoSi of 'he identjjied OO!lIml oplions havc bcen "ommercially-avaibbJc, insl"ll~d, and operati"g in m"ny

full-scale, pCrrn"nL"Tl1 wal-lired ulility boiler insrnllalions il1lb~ Uniled Slales for fiw y~"rs or more.

1'rc_wmbustioLl CO!lIl'Ol." snch as Iud ,wil"hin;:-, fud blending. and fuel cleaning have l,ee" pra"liced and

I'e, formed nt numewus \Ilility powcr planls, typically lor up~Tational and suI rur emi"ion' contl'Ol

reaoons.

Burris & McDorurcll 3-6 Minnkolrl rower Coopcrdlivc, Inc.
NOxDAcr Analysis Study BACT Anolysi., for MRY Stalion Unit I NOx Emi"irm<

CombuSlion conlrols, such as 10w-NOx burners (LNBs) Dnd ovcrfire air systerru;, UfC vcry commonly

applied 10 reduoe NO, emissions ITom fossil fuel-fired powe..planLs. Low-NOx Burners arc lypically

uppli"u 10 pulveri:led co.l, g""COUS ~nu hquid fuel-fired boiler,;. They are not applicable to cyclonc-firell

hoilers. Flue gas recireulalion (FGR) has been pracliced and performed al numerous natul1ll ~as and fuel

oil-fired ulility anll inlloslriol powerpl~nt:> for NOx emi:;:;ion:> conlrol reason". On Iar~c coal-fired utilily

boilers, FGll has primarily been applied fOT sleam lemperalure conlml pmpo""s, no1lor emissions

control. Conventional Gas Reburn (CGR) with overfJre air has been installcd and placed in commercial

operaliOT\ on ,everal cyclone_lired boilers, primarily in ,he eaSlem region of lhe Unitril States_ Coal

Rcburn (CR) with uvc"lfi,c uir has bcc"ll su"ccssfully dcmonslral~-o on two cydone-fired boilers ond

comme,cially installed on Ihree pulverized coal-fired boilers in the Unilcd SlateS. Comhu"lion lempering

(water/steam injection) has been lesled bul has not been continuously practiccd on cyclone-fired coal

boilers. Oxygen_enhanoed comhustinn has only been demonstraled and/or in,tallEu on a limiled number

ofpulverized coal-fired powerplants, nOl on any coal-fired cyclone boil"".

Selective Calalytic ReducLion (SCR) and Seleclive Non-Catalytic Rcduclion (SNCR) are posl-combuslion

. technologies lhal have been applied predominantly on eastern or midweslern bill,minous eo~l-fi,ed

boi]",s. Others, mnsHy comprised ofa combination of available emission reduclion Il"Chnologic." are

oflm rcfcncll 10 ~s "hybrid" or "layered" conLrllls_ V ari~lions of SNCR, such as Rich Reagent Injection

, (Rill) wilh and without SNCR, have only becn iru;lalled or demol1slrntcd on u limited numbel ofcyclonelired boilers_ Other lechnologies, such as Fuel Lean Gas RebumTM Wilh SNCR, hydrocarbon--enhanced

SNCR (commercially available as NOxSlar'M), and Convenlional Gas Reburn with SNCR have only been

demonstraled and/or inst.J]ed on a limi,ed numbCI ofpulve,iz~d ~oal_fired power plants_

Emergmg posl-combuslion multi-pollutanl conlmlledmologles, such as Powc"lSpDn'5 Elcclro-Calalytic

Oxi<l.lion (ECO'"'l, which inolude NOx oonlj"ol, were also illcnlified_ lbese are lypically in the large

pilol-scole commcrci~l lIevclopment phase, and have not been successfully demonstrnled on a full scale

basis on any pulverized coal, cyclone, 01 ci,culatlng Huid bed hoilers.

In most ofthe combinalion 01 "layered" and emerging control cases, the NO" conlrollechnology has been

lIemonsu-ated 10 he capable of controlling lhe Largelcll pollllLanl(s) 0" either:

• a fllll-s""lc b.si" but only wilh temporary equipmenl; or

• a full-"cale basi" wilh permanenl equipmenl bUl in a limited number ofinstallalion,; or

Millllkota Powor Coopcrativo, Ino. Dllms & McDunndl
!lACf Analysis fur MRY Sialion UUil 1 NOx Emissions NO, nACT An,lysis Sludy

• Wilh lef;.S lhan full-scale and fun_lime applioalion.

3.2.1 SUMMARY OF RETROFIT INSTALLATIONS OF NOx CONTROL

TECHNOLOGIES

The, e are a ll11ml,er or bcililJe, around ule cnuutry lh.l have- implemenled or are plannmg 10 illll'lemcnl

rnodilic;]lions lu rcd,,"~ NOx ~mi"sion" T"ble 3-4 summari""s lhe various NOx emissiou ~ontru! syRtem

inslallalion.' elll ,enLly ;nsi.alled, or lhal have !leen demollSlraled 011 a lilli-scale. shorl-lenn ba,is, in

respunse lu Acid Iz"in rc'l"lT"m"nls, EPA', NOx SIP ""11 am! local rcgululions, Or a ulilily invesligating

Ihe Icchno!o!l}'.

TABLE 3-4 - Identified NOx Control System Retrofits

on Cyclone Coal-fired Boilers

No.ofVnllsll) C}'etooe NOx Conlml Teehnolol:}' Descriplion

, Fnol Swilohing/Blending

ji)V'- ~-------~ --_. --------- Sep,,,.led Ovel rue Ai, (SOl'A)

, Solcrtivc Non_CalalJ'lio Rcducllon, wilh or w'llwm SOFi\

- _._----~~-- ._- . _- ..._._ .

i ') Rich Reagenl Injeclion. WIth SOl' A

," Convcm;oTIal fuel rchum (pulvcTioed or mi" ollized coal, g"j, wi SOFi\

-- _.. - -- ~.~ ----1','1 Fuel le.n g.s reburr~ wiul or wiUloul SOFA

-- 22(0) High-dust OT low--d1lS1 SCR, wilh OJ WIU101il OUle' lechnologl.S

" Tail.g,; SCR, wilh or wilhout o!her leehnoloRies

( ), Th;, li51 ofkoOWil NO, <onlrol relrofil in'lall"ion, i, pnmanl y focused on uni" ,n Ihe Umled S""c,

'n",. onay b, olher II,"allallo", Ih., are "onllar bUI weo. "", ;<I"n"I'OO.

(l) - In,IAll"d 1o, NO, "ml",l (w,'houl i"d ",""m). A lisl ofknowTI cyclone bud"r SOrA m,I;,llA',"n, ;> meludoo on

IIpprnd,x A2,

m· Rill ha., only bee" demonslrated wllhlemporary 'quilm"" r", 1",ling. S", le<l1O;e,IIII""U" "re"n'"';n

APl'","I" Al and A210r "eta;I,.

(4) - So,,',,1 co;]v,nllOn,1 ct'.1 lind go> "'~IIrn rel'ulil, h.vc d,seontJllu,d rebum demo"'Ir"io" or rolll;ne opmll;on. S""

rochnioal L,'eralnrc Rofm;]cc li51 OJ\d Append,,!d fo, r",Jheo delails.

(5) - Only one CA,mplc orfod hn ~"" Teb«m relrofrl (wilhoUI OfA) on 0 cyclone-fired boiler h" bern denlOn'l,aled.

Th" sySlcm was insl,lIoo for ,hon-'crm reborn ",,'ing and ha< been ,emovoo.

(6) _ IILgb_du<1 SCR lechnology h.s bccu ,.Irofrllcd on six",," IIS "yd"nc-li,ed holl"". aJl bel;eved 10 have SO,A,

I."w~jn,l SCR, HI U.S. I"vo only I"e" ;".<Ialloo only on pulverIZed cool-fi",d 100;1,,,,, nO'"~ ,m 'yd"""" Ono lail_

gas SCR 1I111,llal,on on a co.l·frred eyclouc [>oiler fou"d '" (;"""ny; "one III thc U.S. Sec lecbmcoll"eoatn",

"·r'",,"',,,;n Apr'''',];' Al ami AI [or d,I"I,.

A mure detniled deocriplion of the various control technolob'Y Tclrolils and lheir cJaim~d crfeCliveness I,

included in lhc lcdmieal de,criptions amI rcf~Tt-'nce hterature In the lechnical feasibility assessment of

IJOIn, & McDolUleil M1Onkoi. Power CoopeIllIJVe, In".
N()~ HACr Analysis Study BACf Analysis forMRY Sr-t;on Un;l 1NOxEmi,,;on,

Appendix AI, and Appendix A2, which includes a Sllmmary ofvarious seleeled U.S. NOx emi..,ion

reduotion retrofil projeels.

3.2.2 SUMMARY OF FEASIBLE NO)! CONTROL TECHNOLOGIES FOR MRY

STATION

\'-'.

-"'--

One examplc of fuel swilching appl ied to a cyclone-fired boiler was idenlified. Ottertail's nig Stone Unil

1 wa.' originally designed lo bum North Dukota lignile and was swilched lo we,lcm subbiluminous (PRE)

coal for reasons unrelated to NOx emissions redllclion. Big Slonc Unil I and MJL Young SlJlion Unil2

have ,imilJr boikr designs, and MRYS Unil I', boiler is approximJlc1y 60% as large as MRYl> Uoil2's

boiler_ Thus. eonv"",ion ofMillon R. Young Slation Unil I·, hoiler to fire PRE coal Or a lignileIPRB

blend i, teclmieally possiblc. Th~rc are nO railroad facililies provided to serviec lhc Millon R. YolJl1g

plant. Additional opernlionJI and capital cosls 10 bring in large quanlities ofPRE coal will be significant.

BJSed on u comparison ofavsilable emission dala between Ollcr1ail's Big Stone Unit I and M.R. Station

Young Unit 1, lhere is no expeeled reduction in baseline (i.e. unconlrolled) NOx emissions from

-,witching to PRE from lignile al MiltOn R. Young l>lalion. AlLhough fuel swilching at Milton R. Youug

SlUlion is lechnically feasible, lhis allernalive will not be economically compelitive wilh olh~T NOx

control ICchnologies lhat offer betler resulls for J much lowcr combination or oapilJI and opcTJlional

·cosls. For lhese reasons, il has not heen cnnsidered flllther as an effcctive NOx emissions control oplion

[or MRY StJlion Unil I boiler.

Sqmmlcd Oyerfire Air (SOFA) is the mosl commonly-applicd, ~ombusllon-fe1alcd NOx emission

reduction Icclmology that has beeLl pl'Oven effective on cyclone-fired boilers. A version ofseparated

overfire airspccifieally dcsigncd [or increased NOx emission reduolion perforrnunee ror Iignile_firc(l

cyclone boilers, referred lo as "AdYHneed SOFA" in this analysis, can be inslallcd On bOlh units al M.R.

Young Station. n,e Imtential operationallimilation, mentioncd in lhc delailed feasibiliLy diacussioru;

induded in Appendix Al for deeply air-staged cyclones assooialed wilh sepaTilled overfire air are

cJlpCCled to limil Lhe control eITectivc-ncss ur lhis Icehniquc, alonc and in combinalion wilh other reasible

NOx control options.

SeleClive Non-C".atalytic Reduolion (SNCR) le~hnology is a [orm orposl--c:ombuslion NOx emission

control thaI hus been succcssfully applied on numerous utiliLyboilers burning caslern biluminous coal,

midweslern bituminous coal. and, (0 a ksser CJlICm, "'CSlCm subbilUminous coallo reduce NO"

emissions. SNCR has also been used on rue! oil and naluml gas-fired uniK SNCR doe, no! appear to he

MinnkOI. PowerCoopelalive, Inc. ;-, noms & McDonnell
nACT Anal)"';., fur MRY Smlio" TInil I NOx Emi<,'io"-'

~--~~~------

NOx BACT" Analy'i' Sru~y

dependenl ~ireclly on lhe lype o[ bomers (wall-fired, langent'.lly_fircd, and "ydonc-fired) c-mploy"d in

lhe boiler' where il h'," heen Lnstalbl, wilh or 'vilho"l air-slaged combu"llOn wilh ove,li,e air Ln (illl

OpenlllOn, Tru' conlrol lcchnology adds un.'a (or ammon;,,) rcugcnl 10 the hOl [unlace ga",,"' m the "pre,

[umace to chemLcaJJy reducc nilro;:cn oxide.'. SNCR wa, consLdered l"eImioolly ro""ibl" [or apphc;llion

on bOlh "0;1$ "l M.R. Young Slation. SNr:R oall he operalerl wilh mld wilhoul SOFA VariaL;ons of

SNCR technologLe., "uch af< Hydr"earbon-enhanccd SNCll (JlE-SNr:R) a"d "RolarJli~" have been

Ln,l" llerl On pulvCTlznl coal-Iircd boilel, hut are nol I,mven Oil cyclune boile". Thi, is described in delail

in Appendix Al.

Rich Reagem Injeotio," (RRl) lS" runn of SNCR under development .,peoi lically inlen,iL,,1 fur NOx

emissions oonlrol On cydone boilers. A, ofOctoher 1006, RRJ has been d"",onsln'led bill has nol been

commercially insl"lled and placed in conllnuous operalion On u cydone-fired boiler, e,pecially one

burning coal wiLh high fouling aLld .,lag Icmp~T11l11rc ,cm;ilivilies associated with lignLle ,ul'plied rrom lhe

Center mine. RRI adds agucOllS urc" reagenl lo lhe hoi furnace ga,e., l\e.r lhe cydoncs, whi~h mu,l be

devoid or frce oxygen ,n orUcr lu "void oxidalLon of the urea whioh wi]] incrcu,e NOx <"fl1i'~lOm. lUU '"

eomi,k,"d t,'("hnie"lly infeasible for appl Lcalinn on the cyelone boilers al lhe Millon R. Young Slatlon al

lhe present time. ThLS i.' de.'cnl"'d lJl dclail in Appendix AI.

Variou" (orms uf fuel T~bum wilh and wllhoul overfire air are 'YPeo of cumblislion-TClaled leehnologle"

lhal have been demonstraLed and oornnlL'Tci"lly insl"II",1 on plilverized coal, filel oil-fired, .nd oydone

utility and indusllial boiler,. Nalural g"f<-consumin;: vorialions BUch as Convenlional Ga" Rehurn (CGR)

and Fuel-J.ean (,as Rehorn (1'LGR"") havc bcen applied 10 cyclone hoilers hw "Lng bilumiTlOU' ,md

suJ,billlrn;nou, coub, High copil"1 cosLs expected for il\"la]];ng" nulu[1,1 g'" pipeline and high operaling

OOSls fTOm comumplion of large volumes o[.,uoh [u"l makc lhese "ll("TTmtivcs ecunomically unlavorahle

for bolh unils"l M.lt. Young Slation. Puh'"ri,cd orminonized coal rebllm, m combination with SOFA,

are lcohn;cally fcos;blc bllt will rc'l"ire exlensive capital, opernling and maimenance "o,ls for f"d

grinding egu;pmonl and raeililies when ;nslalled and ol'ermed ror bOlh unil, "I M.R. Youn;: Slalion. Till"

is ,b~TIkd in dclail in Appendix AI.

F"eI elc"ning is 0 lechnique nonnally applied lo rednce Ihe sul[\lT or ash conlent 0[" fossil fuel prior to

combuslion. No example" or ruel cleaning orNorlh Dakula li~'IIite or we,lem subbiluminoll.\ coal slnclly

lor NO, emi."io"f> redllCiion wcre found in ;]v"ibblc technicall LtemlUtt_ This lcchmq,," is consirJered

inrea"ible for NOx emissions conlrol ofM.It. ¥Olmg Slalion boikrs ~l lh" presenl lime.

Bum' & Mellonn"ll .1_10 Minnknla Power f:oopeIalivc, Inc_
NO, BACT Analysis Study BACT Analysis for MRY Station Unit I NO, Emissions

High-~usi. low-dusi. and tail-gas varialion~ ofsdeclive calalytic reduclion (SCR) lechnology have been

applied on pulverized coal and cyclone boilers as a posl-combuslion type ofNOx emission C(Inlrol

throughout the world and in lh~ Unilcd States, excepl on uniL.s firing North Dakola lignile_ The severily

of catalyst bl inding and plllg!,,,,ge [rom pJrtieulale mailer and flue gas,,", emilled from eyc1on~-fircd

boikr:s burning North Dakota lignite precllld~s the lechnical le.asibl1ily for :successful "pplicJlion ofsuch

SCR technology On Ihc EGU, .1 Ihc Millon R. Young Slalion. 'Illis i, de,cril.>ed in derail in Appendix A I

with supporting docum"ntalion in Appendix B.

'lbe resull.> of Step 2 or lhe No,. BACT Analy:sis for delermining Lhe lechnical feasibility of rOlcnli~1

controllechnologi~s,including various "layered" combinations, are listed in Tabl~s 3_5 and 3-6.

TABLE 3-5 - Technically-Feasible Potential NOx Control Technologies for

M.R. Young Station Cyclone Boiler.:;

In Permaneol, FolI_

Seal. S.rviee 00

- Exisllog Coal_Fir.d

Cyclone UlllilY Technically Fea.ihl. on M.R. Yonng

Coolrol Teehnt>lo '" Dollers? Slalioo Unill hoiler?

Selecti V~n~~n..caI"1ylic

Yes!'1 Yo § R~duclion SNCR)

-·Conv""lional Gas Reburn Yes' , Yes"';R uircsSOFAorASOFA

Coal R~bnm Yes' , Yes"'; R ujres SOFA Or ASOFA

Fnej Lean Ga, Reburn Nn' , Yes" (wi orw/om SOFA or ASOFA

Adv"nc~d SOFA No'"] Yes'·'. Jncludes r~locale<.lli ilc ngvcnrpons

S~ a"'l~d OrA (basic SOrA Ye,'"] Yes'"]

Combuslion 1m rovemenl' Yo, y.,' ]; I ically included wilh se aTil(~dOFA

Flue Gos Recirculalion Nol forNOx conlrol Yo,' ) (not ex eCled 10 r~duce NOx furlh",)

Fuel Swilch;" I Dl~ndin Yo Yost', (not ex eCled 10 r~duce NOx furlh",)

S"" le,hTIl<ll1 f<ll.,b,hly dela,l. and Illc:rllrure Refe",n"", In AI'pend'~ A fo, d,lalls.

(I) - All polenLi,1 ,ombinol;on, of L<elmolos;es nOII;,IO(], Soc d,scu,,;un of"layered"' <cehnologi"".

(2) _ A"nmc, tiSe of urea for =gcnl. Limil,d number of aClive In'lOU..ion, On cyclo"e-fire~ bOllors b"ming ="l<,m

,ubbiluminous (l.e. Powder River aasln or rrlll co,I).

(3) - LimilCd number of,Ol;v, COn""I;o",1 !% ...bum (CGR) in.tlilalions on cyelone.-fired Doller> bum;ng PR.ll c"l.

(4) _ ~;mil"d number of uomon,lmllon. or ,oLivo inSfal]"'on. ofpulverlzed 0' m;trOm'.e<f coal rebum cyclone-firod boil=-

One d,monstr.ll;on ofpulvorize<f ,,,,,I "bum;ng wilb PRB COllI " .. he," perfo,,"",d on , eyolone-n"d Doile,. "0 longer

acl,vc. O"ly une 0<1;"" porrrunenL coal,cbum insLall"ion OLI cyclone-n,ed ho;l,r ,LIming ",>Iorn bilum,"ou5 ooal, n"""

bumin~ "",",em .ubbiluminou, coal or ligni"'.

(5) - Only one .hon_lerm "'" d,,,,,,o,,,aL;on ofFtGR"'" on 0 cyclon"fiTO(] boiler huming coal with "I"'''''''d overfirc ,ir.

(f,) - No cyclone boil"'5 firing Nonh Da'Ola ligniLo have in",II'd ha,;c 0' .dv-dnc<d SOFA. Sec APJlond,x A.

(7) - Con.idered pan ofSOfA insl,tlaLion [o<coal hoilcn; wiLhoUl combu",i"" connols for NO~ redLlo,lon.

(8) - No e"lIl'pl« o[L1sing rec;""I,tod nllc ~05 on COlli_fired boile", for NO, 'rniss;"ns e""ITOI w<-~o found in ,,,,,il,hle

'echni",,1 1;lor,'urc. Zoro addilion,1 No" red"Ol;O" pOle"li'l "'peel<d from In15 lcohniquo .Ione [or MRY51OI;on Unil I 12.

Polenlial NOx reduo,ion improvomeo, on MRY Un;l I 12 considcIO" p,rr o['"oilvo",rn"' SOFA_

(9) - z.,,,, add;,i"",1 No" ,w""ion poleoli,1 c'pcoled from ,hi, ,cohmque (.""",Loh,,,g from lignile 10 lignilclF'RB hlend, Of

IOO%PRB) alono for MRY SIO,ion Unil 112.

MinnkolO Power Cooperolive, Inc. 3_]] Bum. & McDonnell
n,\CT Andlysis for MRY Slalionllnill NOx Emi",iOIlS NOx BAC r AIlal}"i, Slnuy

TABLE 3-6 - Technically Infeasible Potential NOx Control Technologies for

M.R. Young Station Cyclone Boilers

Tn Perm"nCIlI, FIlIIS""I" Service on

EIi.'lin~ Cn"I-Fi~cd

C)'dnne Vlili'y Tochnic"ll)' Fe"s;ble nn lI-I.R. Young

Cnnlrol Tochm,lngl"" Iloil"r"~ Sl"lion Unit! hoilor'!

Seleclive COLalylic RtdUCLioll No'" - IJnrc,ulvaLle fOllling "nJ c"laly"

(SCRl: convcllliunal (high d."ellVDlion proble,,'" ""1'CClod. See d;.'ClL~,ion

uUSI); Low-du.l; Toil-gn, Yes'" I No I Yc,'" ofSeR fe",ibilily ForND Ii nile.

EltCI,0-CalalyI1c OxidOlion No, ha, nol Leen domomlrdled fu]l-{;Colc nor

(ECO"') No roached c01JUlIerc;al availabililY

lIE-SNCR (osi" ammonia) No' , No'''. 11., not beon dcmonst,med on eydono.

ROlamix(ROFA'SNCR) N"'~ No'''. H.s 1101 becn dcmunstmled on eycluno.

R;oh RoagcnlllljecLion (RRI)

No")

No' J. Roql1ires oxygen-free fllmaoe CIlvirumne'lI,

wilh ASOFA var ing air/fuel would illcre"se NUx emissions,

rrm + SNCR ","h ASOFA No" NoL", See foollloic alld feosibil;ly u;,cussiorJ.

AdvanceJ ConveniiollOl Ga.

RehuOJ (ACGR) + SNCR NO'" No Bo, nol hccn uemonstTalou 011 c clone,

CIlOIll.churn , SNrR No'"' Nu. 110' nOL bccn ucmoJl5IT"tod 011 c ·Jone.

Fucll.oan Gos Rebum + SNCR Nu'" N" Ib, nor heell uemoll,<ITaled on cyclone.

ROLaI;ng osed-F;rod A,r No'" No. Jlos nol boon uemunSIJOied 011 cyclon~.

Oxygen E!ulOllood Combu,lion N""" No. ll" uor hoon dOIJlOn,"aled on c clune.

Waler Inj~clion No""' No''"'

hel Ck"n;nJ!. Not for NOx c"nlml No" I

' (nol ex ocleu to reduce NUx fllrlll",)

Se, leohmoul f~,~'I"llly deL",l, ,ml 1,1,,",u,e j(dcrene,", '0 Aprend,x A fo, ~oLa,l,

(I) _ All po"nli,,1 oombioaL;ons of[<chnolog;c, n"llisted, Sec oii,,",,-,ion nr"!oyer",l" lech"ologies,

(2) -lim,i,-,I "llmbcr o[,c,;ve ,,,-,m!laLlon, on ey,lone_lired boiler, bmn;ng wesLcrn s,,~h;,"llli"o", cool.

(J) - No Idonl;li,d Lns",ll"io", "" ,,,.I_flred boile" no ,"e lJn;led Sidle>. One lall_coo SCR "" oyclono bOlIc~ io C;",,,,,ny.

(4) _ S"" dLSous;iu" orSCR fcallb;I;ly Ii" ND Ilgnile '" App,,,dlx Al "n" App""li, R

(5) - Hy,J","", Ilon_enh""c<1 SNell h" nOL ~c'n ,J,,,,onsrraLoo un " ,yclone-flred 00;1", no, an)' bOllcr Ii,;"g ",e.sLcm

.lUbb;IUm;nU"' 0001 or lign;lc

(6) _ RotaLlng Oppo,ed_l'ired Air w,,~ '" w;LI,ouL SNCR h" ""' bee" demon>Lr_Iod M 0 ey,lone-firctl "nil,f. No "PP''''O'

';S",I;''''I ,dvanl"S" over SOFA on cyclnne_nrc<! boilcrs-

(7) - R1eh R'''g''"' Injeo';"n h< """0 'neeess[\llly ~o",n""ralCd fOT brid ~"iods wllh SO,;\. w;ll, and wi'~o"l SNCR aL TWO

cyclone poworplo,,1S- Thcrc "" n" po"".ne"1 RRI in'I"II.,iOLJS oompkl"d "nd operaL;o",1 "' o["May 2006, D;[fien!L;e<;n

m,;nt,,;nnl~ '0 o,y~'"1l_f,ee rn,",o<: env;",n"'''''' '" MRY SI"I;un [,,,,1,,, where the ",ea Ica~cnL wuvlrl he inject'" duo Lu

eyclono "rll'el imh,l,ncc, <I",;nB alr_>L"TVcd 'omIHL<I,on would ;ne'''''''' NO:< em;,,;"",.

(3) _ No known "e""''''lmllOns UT l""'''",''"1 ;n",lla<ioo, "rAd"anced eon"enl;"n,,1 B" rebum (CGR) 01 fLGR'M or

plllv,,;,cdlm;oTon;",J ooal rcbllm (PeR/meR) In oombi""I;"" w;lh SNCR oa eydone-nred bOllers CGR and I'LWmCR

requiTe ocp"aLcd overn,c air. fLGR'M he> heo" arplLed Lo plllvc~;"d coal f,nn~ "';10 a",j wiLhn", SOFA, w;LI, a"d w;Iho"l

~NCR; FLGR'" wiLh SNCR;, ,Iso ""lI,d anl;n,-enl,a"ced fuel Jean g" ,e~,,,n (AEFLGR'M).

(9) - Nu kmn,n demon>!"I;"'" or pcnuancn' ;"<I,,llol;on, of o'YE,n-.o"I'aJleed comb",t;"o (OH;) on cyclone-ii,a! bol"".

(10) _ No pem"In""II~ IIlsL,lIe" e'"nJ),Ie< of",,"~ Ihi, Led'n;qu, oo,"iouoLlsl~ On ""ai_fired oo;k" were fOlllld in av,il"blc

le'''"kalli,«aL",e. NoL sui'able rm h;gh_mo;sture l;gn;Le fuels.

(11) - No kno"" demon,i""ion, or pc",,"oenL i",,,,lIaLlOn, of L"i"S II"., L""h"<q\lo eonlinu"".<ly 00 oo,l-Ii",1 100,1", for NO.

em;s.sion' ronLrol were fo"ml III 'Y:lil,blc ,c,h",,,,,1 IIlCTlILllTC,

'7, >. '> ,<

•

.

•'

Bum, & McDOIJlloll -1- 12 Mimkko", Power em'p",ali,,", Jne.
NO" BACr Analysis Study BACT A~.lysi, roc MRY 5,a,ion Unil I NOx Em;.~,i"",

Addilional crileria besidcs te~hnical feasibility are ulili7.ed for tcchnology sele~lion in a BACT analysIS

have been indudcd in Ihc following seclioIlS summarizing conlrol effectiveness estimalCS, capital plus

openlling and mainlenance coSI cSlim~lcs, energy imp_cIs, and environmental impacl.S:

• Conlrol effcCliveness (i.e_ percent pollulant removcd)

• Exre~led emission ralc (scc Tables 3-7, 3-8) and cmission reduction (Ions pcryearj

• Economic impncls (Iolal cost and incremeLltal cost eiTcclivcness)

• Energy impacls

• E~viro~m~ntal impacts (oilier mcdi" .nd ~missions of loxic and ha:7.ardous air pollut>onl~)

3.3 RANK OF TECHNICALLY FEASIBLE NOx CONTROL OPTIONS BY

EFFECTIVENESS

The lhird Slep in Ih~ ''1op-<!ownn BACT evalu"lion is to rank the remaining: co~tmltechnolo~ies by

effeclivencss. The purpos~ ofranking the control Icchnologies is to cslublish hierarchy thaI '»laces al

lhe ''lop'' lhc conlrol lcclmology that achieves lhc IOWCSl ~mi""ion lcvel."

The ~;;'ission reduclion (oontrol elTcclivcncss) percenlages developed for mnking the "vailablc No,.

emission conlrol oplinns considered feasible for Millon R. YOllnl; Sl~lion Unit I are shown in Table 3-7.

ThCS~ ai'e estimales bas"d upon engi~eeringjudgmenls wilh considerations of,

,

• 'Boiler h~al input mles a,sociat"d with r~a1islic uppcr boondary operaling assumptions;

• bas~line ~mission rales correspondmg 10 the realislic upper boundary np~1 aling assllmpliun:;;

• lhe gencrJI combostion properties ofNorth Dakol:llignite;

• I'ublish~d and availablc cmi.sion reduclion performance achi~ved al olh~r similar u,ility

powerplanls (cyclone-fired boikTh);

• compuler-d~..-ivcd prediclions; and

• inclusion ofperform.ncc margins 10 allow for variu!iens in fn~], wealher, equipment condilion,

and othcr factors lhat prevenl the ullimalc peak short-lerm performance from h~ing reliably

,uslained over Ih" cours~ oflong-Ierm op~ralion.

These NOx emis;ion level and reduction percenlage cs!imalcs include adjuslment. ofpreviously

lkmo~strated or predicled performanoe Ihnl reI1~o( diffelenccs bClwem North DakoLa lignite "fill e"Slem

or midw",lcm bilumjl\OlL< and weslern subbiluminous coals.

Minnkola Power Cooperative, Ino. 3-13 Bums & McDmmdl
BACT Amly,i., rOI MRY Slation Unil I NOx Emi,.,iull.' NOxBACT Analy'l' Sludy

The numb~n; "ssume lhc cslimate{J capabiliIy orIhe cmployed lechniqJlC is achievable and sJlslain~hlc

(Innl\-lc'r111) and Ih,,1 polentinl operalionHI limilation, menlooned in Ihc feasibilily disclL%iom allow the

succe"r"l praclice or Ihe ledmi'l"e or leehnology. None of lhe remaining conlrol oplio", It"S bcen

illslallcd on n GycJone-t'r("d boiler burnmg Norlh Dokol" lil,'llilc. As ,;nch, Ihe exrress<:d conlrol

pcrcenlagcs reflect lho usc of el\ginccringjmJ!,'ll1cl1l, bosed on the lislcd Icchniquc or lechnology

Jlpplic"lion. Thi, is pat1iculurly periill~nllo all control oplions Ihal involw alr-slagcd conlbustion

associalc(] wilh variouo funns ohcpamled o,'~rfire aiL SO!'A-ba,cl! ~ontrol., for cyclone-Jire<1 <:oalburning boilers have typically reduced NOx cmi,,;ion levels sinni[ic"nlly from Ihe precontrol baseline,

nnd whIch allow or enhance furiher reduclions when combined wilh olhe, cuntrol tec1mi'l"c, and

Ic<:hnologie,.

3.3,1 ESTABLISHING BASELINE NO~ EMiSSIONS FOR RANKING CONTROL

OPTIONS

Bcfore Ihe V~nous fea.,iblc NO, emissiun con~-ol allemal;ves can be estimaled nod ranked in order of

erfecllven<:ss, Ihe preconlrol baselinc level ot· cmisoioll.< and i~ b.sis must be dClcTIllined. n,C EPA'a

NSR Manual rrovidcs genel al guidance for c,IHbJishing eSlim.lCd b"selme CnUSSlOns 10 b<: used for Ihc

purpose of calc lila ling and comparing Ihe control and cosl_effeclivel\e&, of a coolrol oplion:

"The ba>elinc emo."i"ns rate rel'rc>enls a renlJ,lic scenario oful'rcr boundary unconn oned

emissions from lhc ,ource_ Thc NSPSfNESHAP requiremellts or the 'I,plical,on ofcOlltruls,

induding olhcr conlrols nc'Ccssary to comply Wilh ,%llc or local air polMion regulutions, al'e

nol considered in ca1culalmg Ihe basdinc emissions. In othcr word." baselllle emi"ions at e

e,"ellliall y llnconlroJlco cmissions, calculaled usio~ rcalislic uPl'er bounda,y 0p~'n'l"'g

as.'LJmplions_ WlJcn calculating Ihe co'l efli:c(ivcnes3 ofa<1,bl posl-pI oCe" emi"ioll"

conlrols 10 cenain ;nherenHy lower polluling processes, hnsclio<· emis.sions may he "",umed

to bc lhe emi,sions from Ihe lower 110Illllmg proce" il\clf. In olher wortls, em",iun

Ieducliun credil can he laken for Ihe use 01' mhcrcnily lowel' polluling r"'<:Gsses''''.

Also "Ialed in Ihe EPA's NSR Manual:

"E,timaling- reali'tic upper bound case scenario <1oes not me'n Ih"llhe sourcc operales in an

absolule wor'l_cose manner ail Ihe lime. For c~ample. in dcveloping Jl rC"lislic uppcr

buundary casc, baseline emissions calculalions can also consider inhcft-nl physieul or

orem1iom,I "onsb-ainls on lhe "OllrCC. Such con'lr.inls should ac<:mately reflect the true

"IbId, NSIl Man",l B.37

3-14 Minnkora Pow", Cool'omlivc, loc.
NOx BACT All,lysis Shldy IJAC1.· Analy,is for MRY Station Unit I NO" Em;ssions

,

~,

upper boundary of thc sourcc's 3bility to physically operate alld the upplioant should submit

documentation to verilY these constraints""'.

Establishing estimated baseline NOx emissions for a new or existing; sOurCC involvcs detcnnining the

desib'll or operation"l b"is of the emission rate. A ugcful meanS of comparing such emission rales is to

cstablish the unit emission rate, expressed in pounds of pollutant per UT1it o[process oUlput For processes

such as Slcam·electric gcnerating powclpbnts utilizing comlmstion in boilers, the desiled prooess output

(kilowalls or mcg"waUs) can be related to the pollu~,nt-bearing nue gas eleatc<! by Ihe combustion of

fueL Units offuel heat input (millions orBnl.,) required to create a Ull il ofdcslTOO electrical outpul (kW)

and thus the efficiency of c:onverting the fuel heat to suoh eleotrical oulpU! (unit heot ralc, BtulkW-hr) are

irnportanL

A review ofreported hourly NOx emissions for MRY Station Unit 1boiler, including uni! maSS rales

(lhlmmBtu and lblhr), boiler heal inpul (mmBtulhr), and gross electrical OUlpul in mcg~w'dUS (MWJ, "IuS

, p~Tform"d for Ihe operatiog periods in years 2001-2005 inclusive. A rcali"lic upper bound emission case

. ieCll"rio for eoch boiler's lxtselinc cmissions "I Milton R. Young Station detennined the highest

"ummalion of any rolling 12·month period NO" muSS emissions (pounds), along with the ,mmma,ion of

'[he glOSS heat input (mmBtus) and Ihe boiler opef3ling hours for thc some rolling] 2-monlh pcriou

'corresponding 10 lhe highest NO:< pounds. Dividing the summation of the rolling I2-monlh NOx pounds

by he.t inpll! resolL, in a average unil emission ratcs (lbfmmBtu). Likewise, the summalion orthe rolling

12-monlh grOS" heal inpul (mmBtus) divided by the boiler operaling hoUls yields an u~cmgc gross heul

input ",te (mmBtulhr). 'This emission evaluation levC"Jled that;

• Unit I al Millon R. Young Station is l}'pically operated in a base-loaded manner;

• MRYS Unit I 's highest 12-monlh NO" m".,; emissions summa lion divided by the summation of

the same 12-monlh period's he'dt input avelJged O.8491blnunBtu at 'd eorre'l'onding avernge unit

heal input rate of2,744 mmBtufhr and un it gross electrioal oulput of244.5 MW•.

3.3.2 ESTIMATING CONTROL-EFFECTIVENESS OF NO. EMISSIONS

CONTROL OPTIONS

The degree o[success in operalion ofseparated overfire air alone "nu in combi""lion with Ihe other

Selecled feasible ahemali~es is imporlanllo Ihe amount ofNOx cmission reduction achieved. The

emission oon(rol perforrmmee [rom the advanced version ofsep"ratcd ovedirc air (ASOFA) is highly

"Ibid, NSR Manual B.37

Minnko!a Power Cnnp<ra~vo, Tno. J-15 Burn, & MoDonnell
NOx BACr AtllIly>i> Stlldy

dependent on lhe degree ofsucc"" in admitting combuslion air inBu[ficl~.,,1 for complete combu,l;on in

Ihe cyclones wilhoul caming relaled negali ve impacL,. Tbc eunlrol percenlage, es!imn(ed tor fi, mg North

Dakola Iil\nile in the MilY Sialion boiler.' reflect Ihe belid th"l ope' atm!,: Ibe c"i,lmg cyclone, mucb

below "n "vCrJgc cyclone ,Ioichlomelric ,;,110 uf upproximately 0.95 (95% or!hc lhc<Jrcli",,1 "mOLlIlI ot·

comboslion air required for complelc combustion) will nul be succee.sful. Thi, IS due pnmarily to Ihc

c"p"clcd ",Imv"d ui," combu."ioll causirl).';" rcdtlclion in cyclone f"mace gas le,nper.l(urc", IIHl' clearing

a Sll ong poten!ial for molt~"ll sIal; solidifying III Ihe cyclone harrel" slug; I"p', and lower [umaee Iloor

ope"ing". TIlis would impose a grcat ,merruption 10 slcam pTOduclion since forced oUlages would be

fl'quircd 10 Te'rlOVe 'hi" physical ObS""llCliOn helore full load boiler ope' allOn could he ree'lahli"hed. The

lc!'A's dmfi NSR Manual SI"I"" "It i.' llol the "EPA's intenlion to reqlliTe nnaly"i, nf ouch pOS>lbk Jewl of

efficiency [or a conlwl tcchni'l"e, as "uch un al1lllysis would ,esull in a IUTge numb", ofoplions''''.

Thc polenlinl operationallimi(alions [or deeply alr-slaged eyc1on~s a"ocialed wilh separated o"erll,e air

and Go"l r~bum alIemati"e, are expected to Iimil the amounl ofNOx conti 01 pntenlial possible from

"ucces"[ul rractlcc o[ Ihe parliculn, lCehni'luc or 1<-chnoloID'. TillS i, 'lcscrib<xl in Ihe ,klmle,1 ["",ibilily

~i.,eussio,,-, inclnded in Appendi" iU.

The a,lv'Jl1"e~ form of.,eparaIed overlire oir is expecled 10 be effccllve in NOx emi'sion re<1ucliorl alld

can be combmcd wilh olher fensible c"mbu,lion-rdole~ and po.<t--combu,lion conlrol "li~TIlativc~ [or

Ihes~ lip;ni 1e_lired cyclone boilers. The basic form o[SUFA in combinallon with coal rehum, ga" 'ebnm

opliuns, and SNCR, was not included in lhe delailed conlrol cf[ccliveness analy",s ill order 10 limit Ihe

number o[ oplions lhat were evalua(ed.

n,ing an advonced Conn o[SOFA 'yslcm, M,lt. Young SlnlinJl's Unit I', boiler operJling al MeR i"

e~pecled 10 achieve a NOx emission level 0[0.51 IblmmBlu when operating modeslly ail-"(aged cyclone

fumaees with ,ull;,b1c eomb"slion COJllTOls. This level ofNOx reduclion Ii-om ASOFA opcr"tion,

approximatcly [orly pcrccn~ IS based on Ihe ~~pecled ahiliry 10 reducc cm""ion, witboul incurring

pOlential sigmficanl negalive ;mp"cts o[ Ihis tcchnique_ This reduction estimale inclndes Ihe addilional

amonnts of conlwl pOlential "vailnble fTOm opera ling with relocated lignile drying 'ysl',u v~."t ports

nssociated wilb ASOFA opcr"lion wilh modcstly "ir-staged cyclooe [umac"".

-...

Dums & McDonnell ]-16 MinnknLa Power Cooperative, Inc.
NO" BACf Analysis Smdy BALI ADaly,is for MRY Slalion IInitl NOx Eml."iom

------

!f. "

Coal reburn with ASOFA is estimated toreducc NOx emi:;..,ions for M.R. Voung Station's Unit I's boiler

opcrating at MCR slightly less lhan 55 perecm from the pre--conlrul baseline NO" emission rate,

cOLlsidering similar control levels demonsualed by previou, coal_reburn re!Tolits on cyclone-fired boilers

and limitations previously discussed with ASOFA.

Cunvcntionul Gas Reb"m and Fucl Le;rn G'H; Reburn oplions were both assumed 10 be instaned with

ASOFA. NO" reduction from CGR with ASOFA operalion is expecled to be approximately fifty six

percent. l'LGR with ASOFA is expecled to reduce NO" cmissions approxim"tcly forty six percent

Es,imales 10' NOx emission" for M.R. Youog Stalion's Unit 1'5 boiler considered similar c:onlrollevels

dcmonslrated by previous gos-rebum reu-olils On cyclone-fired boiler:; wilh modesHy air_st.aged cyclone

furnaces "mllimilalions previously clisc"'scd wilh ASOFA.

The NOx emission rule for Selec~ve Non-Calalytic Reduclion (SNCR) (nsing urea) wiLh ASOFA is

expected to be approximately 0.J55 I 0.3J, re.,uHing from a reduction in NO" emi..ions ofapproximately

58 percent from lhe 12-monlh avemge prc-eontrol baseline NOx emission rale.

Included in the feasible con!Tol oplion ranking ofTable 3-7 are layered allcrnalives lhal were shown in

Tahle 3_5. The highest-perfonning NO" control altema~ves remaining in consideralion are ranked in

declining: order of expec(ed emission reduction. These combined conlrol oplions re["er 10 "adv;meed"

SOFA, which is c)[pcclc"{] 10 huve significantly I01,Vcr NOx emissions lhan" lypical SOFA "yslem as

applied 10 the MiHon R. Young cyclone boilers.

MinnkOIO Power Cooperarive. Inc. J-n Bum' & McDonndl
HACT Analysis Ii,r MRY SlallUn Unit I NOx Emi"ion, NOx BACT Analysis SnLdy

------------

TABLE 3-7 - Ranked NOx Control Options Feasible for MRY Station

Unit 1 Boiler with Expected Control Performance

(I) AI' "oIOWC5<\"" 0, ml

(2) _Con1rol pereenLages are relaLive Lo an a\'IT1l~C prc_oolltrol cmJSSlon baseline 0[0,849 Iblm",mu ],,,,,.1 on annulli opcr"ion "L

h,gl,e" IHc_control 12_mooril ,oiling NOx so"""a'i"" ,,"'" em,~,io", drvlded by 'he 12-mo"'" he"L mpuL ,u",maliOLl.

All. ROl;s,ion llal. Conlrol

Lab'l'" NO, Conlrol T<chni( ue (lblmOlBlnl Pore~nla c")

, SNCR (usjng 11ITa) wi ASOFA IU55 58.1

" Go< Rehum wilh ASOFA 0.]74 56.0

- - ---- - - -- .

C LIgnilo Rcbum wi ASOFA 0,3B5 5~.1l

----

" Fuel Lean Gas T!ehnrn wilh ASOFA 0.460 4').9

- ..__. -- , Advaneeu SCp"Talc<! O\'edlTe AlT (ASOF A) 0.513 395

--- - - _. _. - - ._--

- lJaseliue 0.R49 -

em,,,i,,,, ,b",,,,'i,,n "-,,ic'",,1 fmm In 'h,~ , " ,- .~""n ,are.

Thc annual e",i",ion levels dcveloped lor T"bk 3-7's ranking lhe feasible allernalives assume IhJL Ihe

highest 12-monlh "vm'f\c prc-rclrofillcvcJ ofunil NOx emissium fur M.R. Young Slation's Unil 1', ~.~-""

hoiler J< a baseline of 0.849 Ib/mmTIm. TIli< wa, delermined from Ihe highe,l Toporte,1 rolling 12

con~,'CuIive momh period's .,ummaLion onourly NOx emissions (Ibs).

The hourly "'TOSS fuel he«l inpllt (mmBtu) was summed over llml same 12-momh lJme pr:riud, ;md ,lividcd

by lhe numbcr ofboilcr upcralmg hours 10 yIeld an annual JVeT"gc ~"" fuel ],eaL inpul wlc (mmBllllhr).

Mullil'lying lhe 12-mo011h avel age heat illpUL rate (mmBtu/hr) by the baoclinc ur contwl ahemallve's 12-

munlh a vcrngc u"it emi.<sion rnle (lblm",)3lu) c'lu"ls " 11-rnunlh avemge hourly NUx emi<..,iom rnte

(lb/hr), Annuol NOx emissions (LOns) ror lhc ba,eline pn'-cunlml cn"d,lion were cJlculated hy

multiplying lhc J2-monlh sumrnallon for boiler operaling honrs durin!; lhe ,,",me perind as lhc hIghest

NOx cmi"ians by Ihe 12-monlh UV"""g~ cmi,sion mtc (lblhr). The annual Ions for lhe conLml oplions

were ealcubkd by m[J]Liplying Ihc allomulivc's "vmrgc "nnm,1 "",is'ion raIe (llJl)'Tl hy a rednclion f~clor

(i t· 2wilc"hle) for heal il1pnl or running plant capaclty and adjoslin!; l>oileT opcrol;ng hours by an annual

uplime (availabilily) fucior. nOlai],; for Lhe,~ udjuslmenl> aTc includc-d io Appendix CJ. Ba,ed un Ihosc

calculations, lhc annw,] cmissiofi> far M.R. Youn!; Station's Unit 1's boiler are shown io Tnble 3-8.

nun" & McD"nudl M;Illll<Ola Puwer C""perao IV', Inc.
NOx BACf Analysis Sludy BACf Analysis for MRY Slaliuu Uni, I NOx Emissinns

3.4 NOx CONTROLS ANALYSIS AND IMPACTS EVALUATION

The fourth slep of a '1op-<lown" BACT review is to evaluate the most effeClive emission controls.

En~w, ccunomic, nnd environmenIal impnGls arc 10 bc con,idcrcd in the Gontrol technology evaluation.

The purpose of the evahmlion is to determine ifthere are any energy, ecunomic or environmenl"l impacts

thal would eliminale lhe top control tcchnologies from consideralion.

3.4.1 NOx CONTROL ECONOMIC IMPACTS FOR MRY STATION UNIT 1

An cvalu"tion was pcrformffi. to delennine thc varioug COgt impactg ofinsLalling f""siblc NOx control

alLematives on Millon R. Young Unil I. This evaluation includcs cslimaled:

• Capital costs;

• Fixed and variable operating and mainlcrmncc eosts; aod

• Levelized lolal annual eosts

10 engineer, prooure, construct, inslall, startup, teSI, and plaoe into Gommcrciul operation lhe parlicular

eomrol technology. The re.,ull" of this evalu"lion are summari'.ed in Tables 3-9 through 3-13.

3.4.1.1 CAPITAL COST ESTIMATES FOR NOx CONTROL ALTERNATIVES

The capiLaI cosls 10 implement lhe various NOx cOIltrollcchnologies were largely eSlimaled from unil

oUlput capilal cosl faG tors ($IkW) published in technical papers discussing those oontrullcchnologles. Tn

the cases of SNCR. preliminary wmTor budgelary cost informalion was oblaioed and used in place of, or

to adjusl, lhe published unil outpul cosl faclors. Thcse coal e.,timales were eonsiderffi. to be sludy gm<!e,

which is + or -- 30% aeeuraoy_

The unit nameplate output cnpaeity (gross electrical output in megawatts) assumed for thc NOx oonl.-ol

lL"Chnologies capilal oosl eslimatc basis was 257 MW. for MRY Station Unil I".

A review oflhe 1mil C"pil~l WSI factor range and single poinl fnctors applicable 10 MRY Station Unit 1

NOx eonlrolleehnoJogie, are presented in Table 3-9. The estimaled inslalled and levelized capital coats

for the highest-performing form 0Lthe various feasible NOx emission reduolion technologies evalu"lCd

for cool-cfIceliv"Tless are 'hoWll in Table 3.] O. Thc,c are 1isled in order of conlrol elfeclivcness, wilh the

highe.,t mnked oplion allhc lOp.

"" Ibid [0001010 number 23.

Minnkol:l Power Cuuper.l;"•• lllC. 3-20 Bums & McDonnoll
IJACT Allaly,j, fur MRY SL:l,ion UniL I NO~ Emissions NOx BACT AIl'lysis Siudy

TABLE 3-9 - Unit Capital Cost Factors of

Feasible NOx Control Options for MRY Station Unil1

Single Po;,,(

lJni! C"pi'al COl"~ Fac(o,"',

AU. R~ngel1l ($lkW)

La~<J'" NO, Con(rol Tc<ln,i "" (SlkW) MJl.YS Unit J

" SNell. (u,in~ meo) wi ASOI'A 20-.15'" .11.fo"').'" .---.

0 Go, Reb\lI11 wi ASOFA 15-)0,0) 70.1""""" ~.

C Lignioe Reb"", wi ASOFA .10_(,0'0) 1g1.51'"'' ... -

0 Fuel Le"n Gas Rcbum wi ASOF/\ ~~

('" 41.4"'-""01

---'"

A /\d~al1ced SepMaled Overfire Air (ASOfA) 5-101') 16.d"

(I) AlLem",ve d,,,~nAlIon h,,, Pc( n .""gnc" from hlghes' '0 low'." u",I)\O, em'~""n r_'e.

(2) II,,,, q,P""! eo" f,etor:s (YkW) onhe.'" ""h,-,<lo,1 kch"olo~ic~ combined by "m~le ,ddllion MtIl,1 ,,,,,,,11,,1 "0'" nlOY

<liffor LhlS due '0 r",;';ve ,n ",'gaLlv, 'yne,~;,,;e effec" I(,ngo 0"-,00 0" pn~I"h'~ valu," or v,",dor [''''ro,.I,"

(J) - Smglc po;," co"' (;"Ior is be,' ",1;m"lc [Of deLorminaLio" of Lo"l m~"101 coS! foe" PdTlicul" l,,"hn"lo~y or cOIllO;"allOn,

"-"nm;n~ m"imllm nnit capoclly " ooscd on EPA", "",""pia'" ,,"ng, Single pomL eosL ligure, in 2006 doll",~

(4) .. r",;",,"OO capilOl coS! for ~NCIt rO'"L """,,,Je ami rLGR pOlO' c,"mOlc demed from December 211114 budgeL""

prop"sol hy foci Tech. Sec Appendi, C2 for d"aik

(5)· 'Ille <;n~le POIn' uoi, copHal eo" foe,oT shown for LI," ",,,Iv,"e,'(]"" vc"ion of SOFA derived from Bums & Mdl"nTwH

inle",.1 daLabase ,nd cost «LunaLe "" NrnLl, J)ak,,," l,gniLc.IiTed cyclone bo,I,,,

(6) - NESCAIIM 20~"\ Techm,,,1 Paper. p""ed ,,' Lheir web.lL," See leclm;,.1 ,e['<enc" m Append" AI rOT dcL"il~

(7) TI" .',"~Ie po,"L "niL e,piLoI cos, foeLor ,ho"n I,,, a eonv'"O';"",1 ~" "bum sys<cm ,"c1udes the e",maLed ,,,~i",1 eo" 10

,",1,,11 " high ~,e"",e "a'm,,1 g" 'ul'ply I"pelino (J I,4 >!kW), and II", bOLh bo,I,", ,I,are the "'1',"1 co,, rn pr0J>O"l0ll '0

,hc" ,0.'I'"""v< r",oo MW gro50 ",Ilp," cop,ei'ic,.

(8) Th< "n~'" poiOL umL capirol coS! CacLo, ,bow" lilt , li~ni<c ,eb"m S)'S'em " highly ,"e_speeific, ond '~I"',"", Ih" new

p,II""i,,,, anJ h",IJ",~ e"dos,,,,"f" rcqllired, The geoe,,1 co.« 'd"~e f", pulv"i,,,1 ,",I-[iTC~ b"ilers 1S InCluded 'n

,he NESClo,llM 2005 Technic,1 P'per: [or cyclone bOil",,;, inclH"c'(] io ,he 2005 WRAP DralL Repon, p:>.lled" ,he;,

\I'd",," Th," ,i"gle porn' ULlH mpllal co" CaeLor lor 'h;> ,I""m,,,,,c fOT ,"c",,,sed PM eoHcc"on e'paCJly i"c1ud," io

II~,,;'e ,,"bum opllon is ~L 7 $lkW. ~ee "d"","1 ",ferenc" i" AppendIX AI for del,il,.

(9) - The unll "'1""'1 e,,,' f"do' Ta"~C fOT fLGR ,pplicollon, on ho,le" w;'h"u' "" ",;"io~ " h;~h-p""u,o naL"ral R'" '>"I'I,ly

Wa.1 no' f<lll"" 1Il "vailable Lcchnical li'eraL",e 11,., ';,,~Ic ....'n' lmi, C'pH'! C(';( Cacom shown for a C",I Icon );'" reb"m

'Y"eon includes 'he e«;maLed ""p;Lal co" '0 in",,11 , h,~h-prc"ure o","ml gos .uWly r'pcl,"e (15.7 $I"W), ,nd 'hot bo,h

lH.oilc" sh"" the eap''''1 eO.1l ;n rmpm';on ", ,he;T r"peel've raLcd MW gfOSS ou'puL "'I'"ci",".

IllU'L' & McDonnell .~_21 M"mkolu PowC''- (:oopordll"~' Illc .
NO~ BACf Analysis Sludy llACf An.ly,is for MRY Sl.lion Unil I NOx Eltllssions

TABLE 3-10 - Estimaled Capital Costs for

NO. Control Alternatives - MRY Station Unit 1

Iml.lled Anllu~[Iz.d

Capil.1 Capilal

AU. NO" Conlml AU.rnaliv. Cos,flI COSl'"

L.bel'" SI,OOO SI,OOU

, SNCR wi ASOFA 8,l1J

D Gas Rebu," wi ASOFA(')'" , 18,006 1,570

C Lignilo Robum wI ASOFA'" 46,656 4,068

B fuel Le.n Gas Rebum wi ASOFA1') 10,639

A Advanced SOFA (ASOFA)

""

4,277 m

llaseline 0 0

(I) _Allen",I1V< label h" been =l~ncd from hlghcSl 10 lowe>l U"" NOx <m">IOn nllo.

(2) • 1",,,,llod ""piral co,l i, <>iim,loo [or dolmnin,lion ofloral car,"l <,,<1 [or a parI;oular 'e'llnoloBY Or

eombm,uotl, assuming 2S, MWg uni, cal"'ci'y fiLmg. All "",I r,gllTC> in 2006 doll"",

(3) • Allouali?<d ""pi'al eo,1 In,i,llcd ClOpilal co," , O.Oll7l an"ual;,~d car,L,1 00" facmL

(4) - Co'" [or go> robum opLioos include hiSh_p,,",uJe nal..",1 gos ,up~ly plpclinc in"",llcd capH,1 CO>l ,f

~S,07S,OOO for CGR '0" $'1,0.13,000 fo, FLGR; and ,"nual,zcd capiLaI co," of$71M,OOOlyr fOT CGR and

$J52,000 ro, Fl.-GR- Sec [""'nol",, #8 .no 10 undcr Tobie J_9.

(5) _Co,sLs for i"crea,ed PM ""lle<lion ,",~<;ly inch<doo in lJgoHe "b"", op,ioo ore S2J,56l ,UUO for LruLalled

""p,'al co,", ,nd ~2,054.000lyrannualized capiLaI co,'-

'3:4.1.2 Operating and Maintenance Cost Estimates for MRY Sta1ion NO~

Controls

'The oper;uion.l amI maintenance cosls 10 implement the vario,," NO" conlroltcchnologies were largely

estimated from COSI u,clors (percenlages ofinslalled capi!;}l co,!>;) c,lablishC<J in lhc EPA's Air Pollution

ConlTol CO,1 Man"a] (OAQPS) for SNCR", alld from publi,hed in lechnical papers discussing thosc

controllcchnologies. In lhe oases induding various forms ofSNCR, preliminary vendorquoles WCre

oblUincd and used in plaoe of, Or 10 adjusllhe OAQPS cosl factors_ These COSI eslimates were considered

[0 be study grade, which is + Or·· 30% uccuwcy.

Fixcd amI vari"ble operaling and mamtenance CO.'13 considered and included in each NOx conlrol

lechnology's annu~J O&M GOSlS ure eslimales of:

• Auxiliary eleclrical power consumplion fur operaling lhe addilional cOnLrol equipmeni;

• Reagenl con~umplion.and reagenl unil COSI for SNCR "ll~TImlivcs;and

• Reagenl dilution waler consumpliun und unil cost for SNCR oHemalives.

?) EPA Office ofAll Qualily Planning m,d Slandards (OIlQPS) pUblicalion EPA!~52fB·02·00 I, Seclion 4.2, NOx Controls - NO, Posl-Combu.tion, Choptcr I _Sdeclivo Non-CalJlylic Reduclion, d.lecl Oelober 2000, po,led at

l~eir website: hllp:/Iwww.cpa.govlllnle.toluiTile>4_2 e~ l.pdf

Minokoln Powor C""'pem'ive, Inc. 3_22 Dums & McDonnell
!JACT Analysi., Lor MRY Sla,inn Unit 1 NOx Emi"ion, NOx BACT An,lysis Sn1dy

• lru.-n.;1Se$ orsavings ill alL"iliary ek<:",call'ower cO"-'umpliun lor chan£cs in cool prcp~ralion

equipmenl and loading, prim~rily for fuel reburn cm,!,;l,;

• Gcneral operaling lahor, pillS mainlenanee labor aod lI1<Ilcrials devote<J 10 lbe addilional eillission

control cquipmenl and ii, impact nn exi,ling boiler equipment.

• Rc,luelions In rev!,:nue expected 10 res"ll limn los, of unil a\'",lablllly, i.e, onlage,,- allribut,o bk: 10

Ihe conlrol option, which reduce annunl nel electrical genemtion aV<lilablc [or sale (revenue).

for economi" evaluallon pUlpo,es, an anumll "verage runlling planl oupacity faolor of %.6 perc"nl

compared 10 a nominal unit output eal,acity of 253 MW, combined will, nn overage nnnual oV<lilability

(uplimc) Ilf S,52H opm,ling hours (91.3 porcellt of 8760 hOI"'; pel' yeor) resultulg in an "nnual ullil

capacity [""lor ot'9~.I% wc!" a<3mncd for Unil I's pre-control hasel;ne mmu"loporation. A henl inplli

rale 0[2,744 mmBlu/hr anu" NO" emlssion r~IC of0_849 Ib/mmBlU were assumcu [or calcllialing conlrul

and cosl.., ffcclivcn~s Irom prC_oonlnll11UlXimurn ",l1illl\ 12 moolh ~um",alion of nilrogen oxides' mass

cmi"ion' ror MRY SlatlOTllJllit L

Tahle J-Il show the et;limalcd anllual Ilremlinl; and mailltenance cosls "nd levelized "nnual O&M cosl

vailles for lhe hJghest-pcr[orrning furrn o[ 11,e various fGHsible NOx emission H'<lLJClion t",·hnO]Ol;ic&.

Tlle,e are il'lcd m order ofconlrol effeclivcnc,s, willl Ihe hlghcst mnked optlOn,"t Ih~ mI'. The cost

methodology summarized In Appendix C3 provide, more deL'lIls [or Iho levelJzed onnual O&M cos,

""leulnlions and <usl [1,eIO,.".

TABLE 3-11- Estimated O&M Costs ror

NOx Control Alternatives - MRY Station Unit 1

A"n".' Lc\'cli,O<! Annual

All. O&M CO\I'" O&M Co'l'"

Lobol'" NO, Conlrol AHem.livo SI,OOO $I,OUU

C SNCR wi ASOFA 5,417 6,764

D {i.., Rcuwn wi ASOFA 2~,641 35,765

C Lignil< H.ebum wi ASOfA 5,362 7,320

n FUjR wi ASOFA 12,86.1 16,062

A Adv.need SOFA (ASOfA) 1,695 2.117

Baschnc

,

" "

_Aile " ( ) m,""" I I:>cI I,,, bo,n "'"','"edf,o","igh<;>1 .. '0 low," u";1 N0, cm",,"n ,al".

(2) . Ann"al "p""I",g and m"in""'"O< co>! fu' pMlCU lar l<Cloloklgy or wmomaliOLl '5 comp,",d '0 ""il

O,L'c\U'O o»Crolion 01 ,n """gc """ on'p"' (244.5 MW~) and "",n"e< a01.J% av,r.~, "",,",1 "",ll"bilily,

which i, h;~h"-'I "'''£ocUli"" 12_mOlllh, or "I",,"on em", 20111-1005, All e,'" figure, i" 200r, dollaLs.

(3) - Level",," anllu,l O&M co>' AIl"u,1 O&M coS!, 1.2,87] ,nnu,h,",1 Q&~l 00" rac,",

nnm, & M<llonnell 3-2.1 Minnkula Powe,- C"up"r"llv~, Inc,
!

I

,

,

,

,

I

,

j

I

j

j

I

,

,

,

,

,

-~,,

••>0•,>,"••">,•"••••

I

,,<

,

!

I

"s••••••",w•,,•••,

j

i ;> i'i

,,

•

>

,

,

•••••

,

NOxBAcr Analysis Study

----~~-~--

!lACr Analysis forMRY Sr.lIion Unill NOxEmis,ions

3.4.1.3

,,'

,,;

(4) _COSI' ro, increased PM collection ""I"',ily incl"d," in lignile r<b"m nl'Lio. are ~2,024,OOO1)T for ann",1

O&M '0'1, a.d S2,S27,OOOlyr aonu,lj""d O&M coSl.

LEVELIZED TOTAL ANNUAL COST ESTIMATES FOR MRY STATION

NOx CONTROLS

In order 10 comrare a particular NOx emission reduclion allemnlivc during the inilial engineering annlysis

portion of Ihc BACT scleclion rmcess, lhe sum ofeslimaled annualiud inslalled capital plus kvdized

annual operating and maintenance cosls, which is referred to as "Leveli7.ed Total Aonual Cosl~ (LTAC)

of expecled rollulant removal by implemenling Lhal ~ll"malive was ealculal~d. nte LTAC lor aU NOx

conlrol allcrrwtiv~s WtlS calculated based on the "arne economic condilioIlS and a 20 yc-Jr projecllife (see

APPc"Tldix CI formelhodology). The unil contml cnstwas then delennined as the LTAC divided by

annualloIlS ofpollulunl emissions that would be avoided by implementarion oflhe respeclive alternative.

The control ahema~ves were also compared by culeulnling thc ch~nge in unil cosl (incremenLaI OOSl) per

incremenlallon removed for Lhe next mosl stringenl allcTI1"live. This idcnrified which alternalives

produoed lhe highesl incremenl of expecled pollutanl reduclion for the c,timnlCd loweslavemgc unnu"1

cost inercm~"IIt cumpared Wilh the ba.<elinc emission ",te. The expected annual number of Ions of

pollUlanl removed versus eslimatcd LTAC for each remaining conlrol allernalive was lhen ploned.

Thc comp~rison of[he oost--elfect;veness of the remaining NOx emission reducl;em K-chnologics was

made and is shown in T~ble 3-12 and Figurcs 3-1 and 3_2 for MRY Slalion Unil I. These figures plOI

eslimaled annual "mOlmt ofNOx removal (emission reduelion) in tons per year on Lhe ordinate

(horizonlal axis) and Lhe eslimaled leveJized lowl annuul coSI in lhousunds ofUS. dollars per year On lhe

.bseissa (vertieal axis), for each ofthe remaining NOx control technologic'S. Points em thc gruph lhal are

f;trlhcslto lhc righl and do.<esllo lhe hori7.ilnlal axis are deemed more cost-effeelive, since they represent

controls lhal achiev~ more NOx removal per dollar required for lolal annual cosls ofoperalion,

mainlenance, and capilal recovery (depreciation).

Although the NSR Manuul rcpcale<1ly prescribes.following a "lOp down" analysis approach for BACT

deleITIlinnlion, lhe developmenl ofa leasl co.,l envelope wilh dominant controls (~s SeC"Tl in NSR Manual

Figure B-1, pJ~C B.42) cle:lrly labels poinlS wilh lower emissions reduclions and lolal Jnnual cosiS lirsl.

i.e. "A", '·U", elc. Lhen procccding wilh labding and connecting poinl' ploUed LUriher away from Ihe zero

emission rcd"clion poinL This "bonom,up" approach is for plotling the leJSl--cosl (dominant) control

curve. The bbelin~ ofeuch unit's NOx oontrol lechniquc allernative ha., followed lhis approach.

Minnkola Power Coop."'Live, Inc. 3-24 llmn, & McDonndl
DAcr Analy,is lor MRY Sla,ion Unil 1 NOx Emi"ion' NUx BACT Anoly,'i' Smdy

TABLE 3-12 _ Estirnaled Anllual Emissiolls and levelized Tolal Annual Cos!

for NOx Canlml Alternatives - MRY Station Unit 1

( )

(2) . EsLim'"cd ann",1 omission 'OJLI "-~'","" "n ann,,,1 c'l",i'y [."OT sjl<elfie Lo <,oil OILem,""" 94.1% wss a"",,,,,d [or

Lhe oo.«I,,'e '""'.

(3) - EsLHT,"'<d annual LOO' of rm,s<Lon "du<',"" ;, Lhe ,Iiffo'on"e 1>,,~·lO'" ,nnuo! bss,linlO Lon, 'nd <alOh ol"",,'i,·e.' "nn"a!

,miSSlon, ([om).

(4) _u-vcli",d To,,1 Ann",1 CO" = 1Innu,I1700 1","'II'd 01,;1;,1 'W;L + LcvdizlOd A"n",1 O&~l cost. Sec no'e ~J I",

Iobles 3_10 ood ]·11 for a"<\",I,,,," <c"L foe'''''' Emi»lOn,",c calcubLoo from "n" ,on;",,,,, raLe', """",1

l,erw,Lage, houdy I,o,'-,,,p,,,, "n(1 ,'n"",,1 hr:s!~f operat'on eoonr",,1 '" ["o.,,,,,',,,II.,,,,·li,,,, t"',nl on "nnu,,! opera"""

" highest allow'ble pre cOnTrol NOx em,~<i"" Cd'•.

(5) _ Ave",g, Cu"L,u[ CU51 Cfl,,,,ven= (Slt"n) 15 Lhe LeICI".ed 10,,1 Ann",,1 Cu" (I OOOSlyr) u,.'Joo by A""u,,1 ~m,,,i"n

ROOll"'O" (10",;1)7). All cosL flg",cs;n 2"[~r. dolla,-,.

(6) _ LTAC lor g"-' ,eb,,'" "I'L"m., i"cI",l. h,gh-p""""re n""ml gas ""I'I,ly ["I'"Ii"" d",,,,al,,,,d G1p"dl "", "fS704,OOOlyr

I"r CGR. ,n,[ >J51,O~O [or FLGR. See fooLLlO«' #~ "," I[I ""dcr T'blc )-9.!

(7) - LT1IC lor "'0""-,,,0 I'M '011«'"," c"I""'y included in hgni'c reboo" 01""'" oc" '1'1","im"L"ly ~2,(I.l4,OOO for

d,,,,",,I,,,,-,1 ""piMI ,u,1 pILI, S2,527,OOOlyr for ,",,,u,,li,,d O&M ''OIL, [OT. LTAC >lIbtu,,1 uf 14.581 ,000lyr.

U""Ji,od

Am","l NOx Tulal Avee.~o

Ann".1 NO" Emissions Annual Cnntrol

All. F.missions'" Rodudion'" CO'I'" Co,I'"

Lab,I'" NO, Conlnll Allocnalive Ton,lvr Tun,lye $I,OOU S/Ion

C SNCR wi ASOFA 4,02S 5,909 7,4 ,2 1,26S

D Gas Rebum wi ASOFA 4,275 5,65~ n,33~«" (,597

C Lignile Rebum wi ASOFA ~,34.1 5,591 11.338'" 2,037

" FLGR wi ASOFA 5,260 4,674 16,990"" J,6.15

A Advanood SOl'i\ (ASOFA) 5,~74 4.060 2,439 on

B,scIiuc 9.9J4 0 0

, _ AIL.","ivo 101>,,1 na, hecn ''''' ""d from hi hcsL '0 lowest unLl N(h c '''~,;''" '.'0

]Jurns & McDullncll 3_2.1 MinnkOl' Powe, Coopcmlivc, In<.
NO" BACT AnalJ"lis Study BAcr Analysis for MRY lit-Ilion Unil I NO" Emission'

30000

35000

Figure 3-1 - NO)( Control Cost Effectiveness - MRY Station Unit 111 )

Milton R. Young Sialion Unil1 NO" Canlrol

Annual Removal V5 Levelized Total Annual Cost 40000 TC---c--'==========CC:·===-~-c-~ A _ Advanced Sep;;",led O\ertire lIir (IISOFA) D.

B = Fuel Lean Gas Reburn wi ASOFA

c= Lignile Reburn wi ASOFA

0= Gas Rcburn wi AOSFA

E = SNCR wi ASOFA

Annual NO" Removal, lonslyr

------------

(I) - All cost fi~UTCS in 2006 dollar.' Numhe« are li"ed and qn,liiicrs aTO not,," in Table )·(2.

The purpos" ofFigure 3-1 is to show the rnnge of control and cost for un feasible NO~ reduclion

alternalives evaluated. A dominant "el ofcontrol al!emalives were dclcrmined by genera ling what is oalled

ti,e "envelope ofleaSl_cost a](cma(i,,<:>,". Th" <lominan( control" cosl curve is the htl'l fit line through (he

points forming (he rightmost boundary of(he data zone on a SC~l(cr plOI of(he unnual NOx rernovallonnagc

versus LTAe for Ihe various remaining BACT alterna(ives. Following a "ootlom-up" graphical oomparison

approach, each oftl'e NOx control Ic"Chnologics ~epresented by a data pointlo (he left of and ~bove (he least

cost envelop" are inferior control alternative, per LI1e NSR M~nual "n<l should be ""eluded from further

aLl,lysis on a eos( efficiency basis.

Minnkola Power Cooperative, loc. 3_26 Durns & McDonnell
UACI' Analy.i., rorMRY Sialion Unil 1 NOx EmissioTl-' NOx HAcr ATllily,i, SLuJy

Orlhe lechnically fea,ihle NOx coolrol ;llIemalive, considered for MRY Stalion Unil I, dala 1'01Ilt. for

convenliormll';% r~b"m (Poml D) ami foel-bm gas "'hurn (Poinl B) wilh advanoed separaled ov~rfire nir,

and IrgllJle rehu'n wid, ASOl'A (Poinl C), lay di&linclly left and ahove the olheJ poinl' ot'the control co"l

poml" s~"ller plol ofFigure J-L rhese control oplion, arc inferior "mllbercfore were eliminaled from

further conlrol co,'l_efreclivenes.' a"alySJS.

Average a"d iLlcremenlill annual co,l" and NOx emi"io" reducIion, tor Ihc domioant lea,l-co.l co"lrol

allernali,'es remaining an~r Ih~ dirTJinaliun of Ihe Ohvlllosly inferior opllons are ]JSle(\ in Table 3-13, Th~

,mnu,,] NOx eunlrollons pCT year, dJvided by lhe lolal kvdized "noual cool, yield,"n "Ver"gc 11ml cosl

(S/lon). Incremenlal cosl effectiveness is a measurc uf lhe increase in margmJI cosl effectiveness

bclween lWo specific allemalives. The additJOIlJl Ions per yeJr of NOx control relalive 10 the previous

appJrenlleJf>t-co'l curve point, divided hy the increa,e;n levelized Jnnual 00,.-[, yields an incremenlal rmil

C"'l ($/10"). Allerrrnlioc]y, lh~ ;"cremenl"l eo,1 cileoliveness analy.,is idcnlifieo Ihe rnl~ "I'change uf eosl

effecliveness wilh respecl [0 removJI benefils (i.e., the slope of Ihe envelope of leasl-cost control

allernalJves, also called Ihe domlllam conlrols cost curve or DCCC) belween .,uccessively more effeolive

nlLemnlive.' which arc con,;dered lechlllcally I""sihle lur Millon R. YOUTlJl S1;lI;un boiler,_

TABLE 3-13 - Dominanl Con(rols Cosl Curve Points for

Feasible BACT NOx Alternalives - MRY Slation Unit 1

() po () g (

3·12, "n~ on 'he £,"ph, rh" ,,,"'ornp,my 'his "blc (Poin" B, C, "nJ D were o1im;n"I"I),

(2) - All oost (igmcs io 2006 doH,,,.

(3)- A"nu.,1 'n';.";"" "due,;o" ,no level;'," ,'0""01 00.11 ofLhe'" "I1","a"""s " "Io""e 10 ",rrron[ co,l, "n~ pre-cunlnl! uniL

MCl( bllSdinc cLmssion raLc.

(4)_ In''''IT,,,,L I",," ")XIn cO"'I,ar ;'0"' berwe," oo""cuL,"" ,lremaL,."" (In'",',) I'<lm 10""''' 10 high,.", ",epl " noL,J,

IncrcmCUlol

Levelizod Lcnli'-cd In<romcnl.r

Tojal Annual Tolal Annual lore.menlal

Annual Emi";r,,, Annual Emission Control Cost

All. NO~ Co,jr"'" Reducl;on'" Cnsl""') Rrd,rl':~lon(" E,~.cfiwn"",

I.ahol'" Conlrol T..,hni "' I 151,0001 r) " ) ($I,OOOlvcl $!lon)"M'1

( SNCK wi -"SOFA 7,471 5,9U9 4,n2 1,849 2,694

A AdViUl<ed SOl-A 2,489 4,U60 2,~M 4,()6U 613 (ASOFA)

, Dom"""L conlrol, eost curvc in" rrom lowest ASOr" 'oh, he" SNCRwIASOJ.A are l,b,ko Lh, "m, lIS '"Table

The incremenlal coot analysis indicales lhat from a cool elTeclivelles< viewpoiol, lhe SNCR WJ;h ASOFA

aUC"ma~vc i"ours a "'gnilioa", aLlLlual (leveli,."I) incremenlJI cosl comparcd 10 Ihe ASOl'A NOx comrol

Ilum' & MoDonne1l 3_27 Minnko13 Power Coopeffiliv~, lno.
NOx BACT Analysis Sludy BACT An'ly,is for MRY Smlion Unil I NUx Emission.

technique (slope from 7.ero baseline 10 ASOFA, I'oinl A was $6n/lon for MRYS Unit I; the incremenlal

co.t (,lope) from ASOFA, Poinl A to SNCR with ASOFA, Point E was $2,694/ton for MRYS Unit I.

Figure 3-2 ennlains a repelilion of the levelizcd lOlal annual eUSI ~nd NOx control inform.tion from

Figore 3-1 for MRY Slation Unil 1, wilh Point B(FLGRTM wilh ASOFA), Point C (Lignite Rcburn with

ASOI'A) and Point 0 (conventional gas rebum with ASOFA) removed. This i, Ihe dominant cOl\trol,

eosl ourve for MRY Station Unit I NOx emi".ions alternative•.

Figure 3-2 - MRY Station Unit 1 NOx Control Altematives

BACT Dominan! Controls Cost Curve(l)

----==

Millon R_ Young Station Unit 1 NOx Control

Dominant Controls Cost Curve

6,000

Slope = inorem8nlal $/lon I

7,000 A= Ad",,"c'" SOFA ,~ i " , E SNCRw/ ASOFA 0 >1 z ! 6,000 (POint. B, C. and 0 ferm""')

"

•

'" $2,694/lon ~' •

0 5,000

0

.. 0

0

" 0~~ 0 - 4,000 0

•

0 3,000 , " 0

•

" 2,000

.. $6131100 ,

, '\. , "

" 1,000 ,,' ,

c" "

,

...'

' '

"

" 1,000 2,000 3,000 4,000 5,000 6,000

Armua! NOx Removal, tonslyr

(I) _Ail oost fi~UT<' in ~OO(, dollar.. Numb<:" aro li>t,d and quali"crs OTe """d in Table J·1J,

In the U.S. EPA's NSR Manual, the EPA does not specify ueceplahlc or unacc~'pluble ranges for avcrnge

(un;l control eo,t,) und incremenlal eosl cffC<:livcncss values. As can be ""en from a review ofTable ]-

]~, Ih~ average levclio<cd control cosl effeclivcnos" (e"lled lhe unil conlrol COSI in Ihis report) r"nges rrom

approximalely $613!lon 10 $6,597/10n ofMRYS Unil l's NOx emissions removed. It should be nOled,

Minokola Power Coopera'ivc, Ino. 3-28 Bums & McDonncli
BACT A".ly';, for MRY S"'-llOn Unil I NOx Enn«;on, NOx BACT Analysis Sn,dy

however, lloullhc hi~cSl eBt;malcd average control co.'L< inoulvc gas rcbum lechnnlo"ics lh"l were

.,hown 10 be ",ferior oplions (nol on lhe dominunl conlrols cost curve) and lhus wcre elimi"aled from

further iml'acl$ onnlysi,.

The iLlcrcm"nlal cosl dTecl"..eLless i, " measure of Ih~ ,n"r~u,c m marginal cost el1tcli vcnc" belween

lwo spccific alternalives. AIltmalively, lhc incremental cost ell"clivene,> analy,i, idenlilles Ihc ratc of

chan"e or,·u,l effGct,veness Wilh rc'l'ccl to rem"vnl benefj ls (l.G., lhe ,lope of lh~ lea,H,o,l envelope of

dom",anl contlOl aILemallvco or dom",aJll conlrol; co,l curve) between <uccc,-,ivdy more ejjtclivc

allcmalives. Thc economi" impacl analy,i, indicale.' lhal f, om a co"1 efftcli"e"e" viewp"j"l, lhe highe.,t

performi,,?, nllmmllvc i, SNCR willo ASOFA {Poinl Fl. This conlml oplion "co""i,krc,1 lc-dmically

1"0.11 bk fOT Millon R. Young Swtion Unit I boil~r bllt incur, a sigmfic"nt an"",,1 (kvclized) i"crerncn",1

eOSI relative lo the next highest fc"sible NOx cOnlrOllCehnique, ASOFA (PoinlA) when ASOI'A is

comp"rcu again" th~ pre-eon lroJ b"Belin~. Thc Ad",mccu Sep"rat~d Overr,r<: Air allernative Ioa$ "n

av"rage unil conlrol eo,l ($613/10n) appruximalely 48% ofthe highe.'l p"rlunning I"asible nhnnalive on

lhe domlll"nl control, cosl curve (SNCR with ASOI'A, $1,265110n). ASOI'A also 10", a much lower

iJlcR"ITll"llWI cosl per lOll r~lnliw lu Ihe pr~·cnTllroJ bu,clinG ("lope from zero 10 Poml A., SG 13/10n)

compared 10 SNCR wilh ASOfA (Poinl E) "e",,1S ASOFA (Poi", Al; Ihc ,Iupe from Poinl A 10 Point E

was .n,694/10n.

The otkr c!<om''''l' of the fourIh 'lep of H BACT a"oly.,i, followmg: ,·conomic ilTlp~"I, "rG 10 cvalun1e thc

fullowing lmpJcls of t"o.,ihle cm"sion conlrok

• The energy impacl".

• The enviLon",ent,,1 imp"cls.

Dums & MoVunndl J_19 Mi'mkobl Power Cooperrll;.e, Ille
i

i

,,]

I

I

I

>

!

",,f,<<

,,,

;§

00

i

0

<• ,l; 0 I 00< , I , , , • ; <,• 1, ,•1j

0'

j

,S

,

,%

,,

,

,

•

!

,,%

0

••

1

,!

j,

l

"l

0•0

I

0•"•••

,

•

j

,•

.~•"l•,,•,•

H'!

,

§

,• .< • •

, ]g

,

,

%

,

,

]

i

e

"

2

,

,

,

•

,

"

•

·

,

,

,

]

~'-

,

•

, ~.

,iii,

•

,

•

,•

0

,

,,,

.~"g

,

,,;).

, ~,..,.. ,

• ]c1 u ;;; • • , ,

~~,

:::1#

•

,,

,

;

a

•• z~~•• I; ~- 2. • ! • , ,

1i

3

,,

"

;

,

,

1

,•

•• ",1

, ~.

,

H

•

s

,

"

,

, '.j I

,

,

•

f

•

•

,

,,

•••

••

•

<

,

<

,

,

•

,

•

,

,

,

j

,

I

,,

J

i

•

"

•"

"

•

,1I!,

NOx BAC!' Analysis Snody

----~-~----

BACt Analysis for MRY Slalion Unil J NO" Emissiorn

3.4.2 ENERGY IMPACTS OF MRY STATION NOx CONTROLS

•

r.;

'1

';.

~<

•

OpeI1ltion of the most cost-effective NOx tonlroi technologies considered feasible for potenlial

applioation at tlte Millon R. Young Station impo,c direcl impatts on the tonsumplion ofenergy required

for thc prodnetion of c1eclT-ical power at the facility. The details ofestimated energy usage "ml costs for

the various NO" control nltomnlives arc s\lmmari7.ed in Appendix C3.

Control aItemative., for reduction oENOx emissiqns were reviewed to delennine if the use of the

teohnique or lechnology will resuh in any significanl Or unusual energy penalties or benelits_ There ore

several basic kinds ofenergy impacL' for NOx emissions oonlrob:

• Potential inecc"se Or decrease in power plant energy consumption resulting from a ehJnge in

lherm"l (heat) energy to nel eleClrical oUlput conversion efficiency ofthe unit, usually eJ<pressed

as an hourly unil heat rale (BlulkW-m) or lhe inverse of pounds ofpollulanl per unit eleotrical

power OUlpU[ (MW-hr)_ This mayor may not ch"ngc thc nel eleclrical output (MW) cnpacity of

lhe EGU, depending on iflhere are physical or imposed limits on lhe lotal heal inpUlto lhc boiler

or ckclrical powe, outpUl.

Polenlial increa.,e or decrease in net electrioal oulput of the Urnl, rcsulling frum changes in

physical optn>lional limilalions imposed on lhe ability to sustain a fuel heat input ralc

(mmBtulhr) which results in a polenlially lower or higher unit nel eleclncal output (MW)

capacity_ This is effectively" changc m net declrical output (MW) cnpacity oflhe EGU_

Potential increase or decrease in nel electrienl ompul of lhe unil, resulling from cl,anges in

auxiliary electricnl POW~T demand and usage (kW, kW-hrs)_ This 1S effcetively a change in net

electrical output (MW) capacity of the EGD.

• POlenlial increase or decrease in reliability and availabilily to generate electrical powcr. This

results in a crumgc to lhe number ofhollis ofannual operalion, nol necessarily a change in nel

electrical outpul (MW) cap""ily of the EGU.

3.4.2.1 ENERGY IMPACTS OF SOFA TECHNOLOGY

11,ere should not he a major imp"cl on energy eon,umption resulting from the opcr"lion of ale advanced

varinllon ofDsepariltc<l ovcrfjre air sySlem. SOl'A does nol signific"ntly change lhe tolal "mount ofair

introduced into lhe boiler, only lhe location where it is inlroduced_ Damper re,islance and supply

pressure imp"clS oflho SOFA system on fan power consumption should be insignilicanL The am"un! "f

flyash emilie<! from lhe ooiler is expected to be rcducell (b' than fivo ]>CTccnt) from the baseline level

Millnko!a Power Couper'live, Illc. 3-31 BUm5 & McDOllllell
BAcr Annly<i.' rorMll.Y Slalion Unll 1 NOx Emissions NOx BACT An.ly,is STUdy

when tl,c SOFA syslcm is in [\ill operalion. Slighlly higher levels ofunnun,ed caL'hon III lhe llyn,h may

o~cur wilh the opera lion ofa SOFA syslem. This could have a smull ncgmivc impucl on Ihc planl heat

rale (higher lltu!kw-hr). The.,e change, nrc c~JlC"ted to bc wilhin the lypical range of current operalion.

There i< a rmenlial reduclioLl in ,eEahiliry und u~uilab,lily of" lib'llilc-fircd cyclone l,oiler to gencrale

Hleam 'Or productiun of ekclrio"l power a< a resul! o[ ,,]Stalling and ol""rarjng a .,epnrated overlire air

sy'lclll. Typical SOFA opera lion on hitum",!)u, 0' w~,tcrn ~uLLitunn"ouswal-f'rcu cyclonc bOIler,

does nm carry 11 sib'lli lie,'''l ad,lilionul risk ofcall,ing insufficicnl or exee",ive accumulation ofslag

wilhin lhe cyelonc barrels Or furnace bollom compared wilh non air-staged comhu'lioo. Reliahle hOlier

upLTJlion depends on avoiding <uch adver.<e condjlions In the cycio<\e, and lowcr rurnacc, whIch cuuld

reqlllre a forced outage to remove the ,olidi (lcd ,;lag prior 10 rcwmmg Ihc boiler 10 generalion production

,ervLce.

Thc eh"lknges of mainlaining adequate slag layer deve]ormen1 and now "'hile liring Jignil" in MRY

Um t I', cyclones under cxcc"" air conditions h"vc bOL'T1 signiIicant during lbe operaring history of lhe

powcrpl,ml, Minimizing forccd oUl"ges resulling from cyclone .,lag ;"ues have Iargdy bc"" ,;ucccssful

lhrough operatIOnal praclJce., that do not affecl day-lo·d.y boilcr reliab;lity anu availabIlity. Due 10 lhe

va, iahjlJty ofCO",h"Slion chamClcriSli~, uf lignite ,upplied from Ihc Center mine, and lhe dependency of

lhe slag now onlhc lC'T11pCTalurc wilhin the cyclone bJlTels or furnace bollom, condillOn,; may OcCOr

dUTing ASOFA operallOn Ihal exceed Ihe ahility to adjuST operational praelic~, suffioicntly 10 aV<J1d forccu .1;

oulages 10 remove the solidjfLed ,Jag.

The polential iml'aCl on annual unJl oper'~ling time dllc to ~ydone ,lug issues associated wilh air-staged

cydones!ASOFA sysl~m op~mlion was eslimaled to he approxllnntely 2% n::uuelion from Ihe assumod

pre-control baseline availability. i.e. 0.97-0.02=0.95. n,e e.'ljmaled eleclrical gcneralion produclion lost

due 10 the reduclion in MRY U",l I's a"nual availahil;ly is shown;n T.bIc 3-16.

3.4.2.2 ENERGY IMPACTS OF SNCR TECHNOLOGY

For SNCR, lhe injeclion of" diluled urea solution wllll'equire some addilionul ",lXlliary power for

hearing and pumping the hquid and (I,;mg eomprc"ed air [or alomiz"lion and conling Ihe rc"g~nl

mjocl,un nozzles/lanccs, on Ihe order of70 to 100 kW. The injection of watcr (uscd for urea dilulion)

illIo lhe bo'le' flue ga, also wi]] have 3 ~m"ll ncg"livc i1111"'cl On Ihc pIanl heal rare (hjgher R!r'!kw·hr),

"llhough lhc vendor ofSNCIl <ystem., advise,; l1,allhe heallelea,ed from thc o"idalion ofa portion oflhe

Li",," &. McDun"ell J-J7, Min"kolO Po~'er Coupcrdliv~, Inc.
NOx BACr Analy,i, Study BACI Analy,is for MRY S,"uon Unit I NOx Emissions

injected urea compensates for this impact. The impact of ~dditional nue gas created by operation of an

SNCR-rclaled system on fan power consumption should be smaiL

There i.' a polenlJal reduotion in reliability and availability of a lignite-fired cyclone boiler 10 generalc

slcam forproduelion ofeketrioal power as a resull ofinslaJling and operating a SNCR-rdated sy"temTypioa] SNCR operation wilh low ammonia slip when llring low-Rulfur weslem subhituminous coal in

cydone_Jired hoilers doe:; not carry a significanl addilional risk of eaLL,ing exces:;iv~ fouling of the

lubul"r"ir prehe"lcr compared with non-,SNCR operalion. Reliable boilcropcmlion dqx.-"T1ds on avoidjng

adverse fouling; conditions in lhe air preheatcr, which could require a forced outage 10 remove lhe ash

deposits prior 10 returning the boiler 10 gencralion production "ervice.

The challenge" of maintaining open pasS'Jge" lhrough thc ~ir prebealer tube.' wb i1c firing lignile in MRY

Unit I's cydone:> uu<l~T typical condilion:; have been minor during lhe opcT.ting hislory ofthe

powerpbnt. Minimizing forced oUlagc"S rc:>ulling from a:;h deposits wilhin lhe air preheater have largely

been suo~=,fullhroughoperational praclice" that do not nITect day_l.o-<lay bOIler reI iabjlity and

aY!'iJ.bllily. Due to lhe variability offouling ~haracleristi~" oflignile supplied fTum lhe Center mine, and

th~ dependency of lhe fouling wilhin thc air prehcaler on wdium, 'ulfur, and ammonia slip cmi,sion

levels, condilions may occur duriug SNCR openllion thaI exceed lhe "bility to adjust opernlional pr~eljces

suf;fi.cienlly to avoid forced oUlages 10 remove thc nir pr<'healer deposils_

The pOleminl impacl On annual unit operating time duc lu "ir prebcaler lonling and Olher rotential issucs

ossociolc<i wilh SNCR syslem opera lion wa" ~stimaled 10 bc an incremenlal 1% rcJucljon from the

assumed pre-control b"scline Or ASOFA availability_ The estimated cleclric"l geueralion produclion lost

due til Ihe reduclion in MRY Uni!]'s annu.1 availability is shown in Table 3-16.

Minnkolo Power Couperali"e.1nc. 3-33 Bnrn<&McDonnell
[lACr Analysis lur MRY SLaLion Un'l 1 NOx Emissions No... BACT Analy,is Sn,dy

TABLE J·15 - Expected Auxiliary Electrical Power Impacts

for NOx Controls - MRY Station Unit 1

E,limnlcd Allnual Avera~e Auxiliary

E1C<',ri<al Pnl>er Demand and COnS""'pli"n

,,,

N(h C,mlcol F. 111 mCnl

All. Gro,s J)e",and~l Power (hage'"

Labd,n NO <Co"l rol Tc<hnique 'W kW ImJ c

, SNCR wi ASOFA n 582.~11

A Advanced SOFA (ASOFA) , 8,O5~

(I) Al'o,",,,.vc nu",be< 1,,,-, b,"" PTcv,ou,ly m,g,len f"'m h'gl",," 10 IOWO<l uoHl NO< O""'>r"n role.

(2) _ The "PC NO, "1"ipmcnL gro'-' ,uxlli" y dc, ,nc.1 powor d,,,,,u,d nr "I,e",",iv,." " 'he 'u"' o[ ,,,,I;v,<1L1,1

«chonlng,,,, combJllcd by ,m'ple ",1,hL'on, AcLUal POW", d,m,md, ro"y d,f[cr fmm '1\;< .I,," '0 po,H,VC 0'

""I}'l;vc ,ynorgj"" <fTc"".

(J) - nc annual 'ha"ge in APe NO, <qUlpmoll' "",iliary e1wricol power dem"",1 eI'c1ric;lj' u"'go in kW-hrdyr for

Lh<.", ""'''"''Iivo> " the oct power der",,,d mulupJ"d by LI,o eSI;m,tlctl a"ouol op<m'lng limc "nd rullmng 1'1,,,,

o'!",oily faClor whiel\ ,,,11,,,,, 'n" A<tiu"mcnL rot "ny "'pcrlro rdi'biliry and eap'"'Ly imp,cls fmm 'h,

;mplomcn""o" of Ih" ,onlrol Lcchniquo. A "c~""vo "duClion m Boo,o,tt'i"n " ao in'''''' JO ,,,,,,,AI ""'" 01""[1'1001 I'''WO; .v,ilabk [or ",Ie.

TABLE J-16 - Expected Electrical Power Generation Availability and Capacity

Impacts for NOx Controls - MRY Station UniL 1

yg gl p g

(2) O""I;ne ,vollob,lily 'S """"cll aL 97,3 poreenL ncsc v,lues "fl"" ",,,,,,,,,,,1 ""oun" of nogaL,ve rcl"biJlLy ,mp"L

"'I'CClod fron' ,I" ""pl'm'n,"Lion oflilo i",li""lu,1 NO>: conleol [ech"i,!"c,

(J) - Annual 10<1 "perdl;ng "01>0 Tc,ol'lng ['Om 'hc impl,men",,,oll on],e "idiv,do"1 NO, co'''",1 'c-c"mqoc is Ihe d,n",o","

beTwoen 'hc ""seline ,,,d e<pe<"d a""",1 OULogo' '"ne<.

(4) _ ll",di", ru,mi"e pl,nl C"l"'cHy faClm "''''omcd oL 96." I,e'<e'''. T'h"," v,luc:s ",fi,eL "lr"""cd anlOU"" of "c!:,,',vc

rdi,I"li'y 'mp,cL ",poeLed lr"m 'hc ,mplom,n"L,,'" "r'h" indiVidual NOx ,,,"[rol kchnigLic.

(5) - A""""I dCClriciLy gel",'L,,," rctIocLion lS on"u,1 ,,,locMn o[ opem'ins Li",e "'ulJiplied by Lho ann"a' "'nning planl

,,'p,ciLy f'<lor ,,,-,ulrin~ fmm Lhc ,mpl,,,,e"'.l;"" o[lhe indJVid"al NO, 'onlroll"hnJque m"I"pliro by 'he Mel( C'I""'y

r.llmg nr 2,3 MW (Mel( gro« ""it dwncol OULp,L cal'"cily),

E'lim~led F.'Hnmtcd Eslim.ted

A"nnol AnnllO[ Anl1l1.1

Average Avecoge Aveca~o

hlimaled Opera ling Running EI"d.-idly

Annual Time I'lon' (;ener:alion

All. Av,ca~e ll.edlldioll, Cal'adly K"t1udi"n

L.bel,n 'NOxCo"lnJl. Tedm; "' Ava;labj]i~",') brslY"'1 F"clm") kW-hnly,-J"

, SNCR wi "SOFA 0.956 273 0."65 67,660,606

A Advancod SOFA (ASOF A) 0.952 '" 0,%6 4fi.586.546

'" AlLornaL,"" "limber hos ""eR "ev,o",1 '55' nro 1'0.0 Ie-A,L <cm"v,1 '0 hi "," Tomoval "rccn", ,

Hum' & Mdlormdl ]-]4
NUx BACT An,lysi, Sludy 8Acr AJllIlysis for MRY Slalion Unill NUx Emission;

TABLE 3-17 - Expected Total Electrical Power Generation Impacts for

NOx Controls • MRY Station Unit 1

() nmbr I y g g»C B

(2) - Thc ,nn",1 eltonge in APC NUx cqnipm,nl '"'iliary e1ectricol [!<'wc:r demand cl,clricily r""E' in kW-hrslyr for Lhese

,lLom",i"", L, Lho ,,", [!<'wer den"'nd mulLiphed hy the estimated ""nual operaLiog Limo and runniog pl,nr capeolLy f,o,",

which ",n,cl, the ",ljU>L,,-.,n' ro, '''y e<poOled ,elJabili'y and cap,cily imp'"" r'om ~" impl'meo,"LJon o['h, conL~\1

lochniquo, AnogaLl'O Tcu"c,ion in g,ner"'ion i,"n in"",,,o in ""ouol n,w <Ioclri"'l row" '''''il"blo fOT ""I<,

(:l) -l\onu,1 ol""LridLy genom'ion rednoLion " ,nnual roduellon of opmlLing 'ime mul[ipliorl by Iho ann".1 running pl'n'

o'raci1y 10""' ""ulli"£ from the Jmplomcnr:IliQJl ofrhe iedividual NO:< oon[fol occhnique mulriplied hy lJ,e MeR "l",oily

r.[rng of2,) MW (MCR ~ro"" "nil <l<o"io:1l "ulpuL <op'cily).

(4) -l\onu,1 eh,nge in ne' dCCLocal power gcncr;Ilion avail,blc [or "Ie ;s ,riLhmclic ,nm ufann",1 power genr:",rwo reduelloll

due Lo , change ln Ihe a"xili,')' elewkal !'Ower c""'timed pi", dIe 011"",1 ge"eraLion rOO"Ol;O" [rom, deore"e m'nnu"1

o>'CTl'ling lim' ,nd """go anno,' ,unning pl'n' c'r,city r"lor "'Stilling rTOm lho impl,m,nt"ion orthe in~iviun,1 NO.

oonlrol [cohnique, eompllrOO wil" oo,olin"-

E,lim,ted

Annual A~e.,age ESl. Tot,1 Annu,1

Elootririly Ch,nge. in

Power Gonera,ion Nel £1'0"'0,1 PDwer

All. V••go'" Redu<liun'" Goner.lion A".ilahle fo'

Label{l) NUx Cmu",l Te<lmioue kW-~"lvr kW_ltn/ r Sale'" kW-lt,sf , , SNCR wi ASOFA 582,411 67,660.606 68,243,017

A Advanced SOFA (ASOFA) 8,058 46,Sg6.546 46,594,605

, AlrernoL,," " e 10,,-, b,e" >reviou'] -; Red r'Om 1""-,, ,.."..,,,,,1 [0 ili he" "mo",,1 rcenLa e.

3.4,3"-0 ENVIRONMENTAL IMPACTS OF NOx CONTROLS - MRY STATION

NilrogC"Tl oxidc" [C"et wilh oxygen in the almosphcre lO produtCC elemental nitrogen amI OZOnc (0,). This

is one ofthe common caus,," ofviSIble pollulion in the atmosphere rcf~TIcd to as "smog"_ Opera lion of

lhe variO)-lS NOx eonlrol technologies considered lor polenlial ,pplic,tion ,t the MiHon R. Young Slation

impose direcl and indirecl impacls on the environment. The most pronounced direct environmental

impacl cxpcoteu [rom operelion ofany or(l\e NOx COLlIroI options considered is tile reduotion ofozone

umJ improvemenl in almoJ.',pheric visibiJily (i_c. rcuucc<l visibilily imp.inneut) downwind orlhc facility_

3.4.3_1 ENVIRONMENTAL IMPACTS OF SOFA TECHNOLOGY

The operation of, separaled o"erfire air system is expected to slighlly inere"se carbon monoxide

concentration, in the slack flue gas. The advanced [mm of SOFA ahem,tive is expecled 10 slighlly lower

Ihc nmounl ofparlicu!"IC mailer cmiued from thc boiler ~nd mIly mise the amoum ofunbumeu carbon in

lhe Jlyash collecled for land disposal and emitted to lhe almosphere by small incremenls. Allernatives

involving fonns ofgos rcbum should c:<pcricnee lower parliculate emissions, 3m! , reduelion in the

amount ofhoiler l'ollom and flyash requiring disposal.

Minnkola Power Cot,pcrali.<, lnc_ Rum, & McDoundl
BACT AnalY"i., fOJ MRY Slolion IJnil I NOx Emissions NOxBAcr Anol)"i., Stndy

The envirOllmcll~11Imp~ctlimll potenti~l reduclion ofannual unil operaling lime by approximately two

percellt clue 10 cyclone slag issues associated wiLh ~ir_slaged cycloneslASOFA ,yslern opcl1llion will be 10

n;ducc the annual amnunl (10m) of nitrogen oxides emilled. "nd thcreforc Iho annuul number ofNOx 10m

remov"l1 wi]] inc",""", by approximalely Lwo perceLlI.

3.4.3.2 ENVIRONMENTAL IMPACTS OF SNCR TECHNOLOGY

0l'emlion of;, eonvcnLiom,1 SNCR syslem is not expecled to sigLlificanLly impact emi"ions of CO Or

vol"lile organic compounds (VOCs).

Orel'ation or ~n SNCR ~y'l~rn w,ll normally er~"le a small amounl ofllnreaoteu ure" or ammonia to be

emille,!. The amounl of ammuni" siJp produced hy SNCR depend.< on the amounl or reagent ul, h""lion

nnu locaLion of lbe injeclion poinls. [[igher SNCR NOx rcduoIion p"rronn~nce involves b'I"C"ler amounts

ofreagenL usage and ammonia ,III'. Thi, " lypieaUy conlrolled (o!c" lh"n 10 ppmvd, especially when

Lhe ro.,.,'hle fOTIIllilion of wlfllle~ weh "' ammonium ,ulrate l(NII,),SO,] and ammonium bisullale

fNH,HSO,] 'vill be more problemalic at higher .,[ip levels. Sullur lrioxide (SO,) fonnecl during

"OmbU"lion iLllhe boiler CO" combine Wilh ammunia during p""agc lhrough Lbe nue ga, ducLwork 10

(0"" lhe s"lf;,ICS.

Some of Lhe unreacIed ammonia from SNCR operal;on WIll b~ eollecled wilh Ihe flyash in the

electrostatic rl'ecipilnml'. A"y remaini"l: ammoni" ,lip IhaL i, not collecled or conden""d in lhe a;r

poHulion conlrol syslem ""ill be emilled from the stack as an aerosol or condensable parlieulale. This h,,"

Lhe POl'-~'li~1 to iuerc;"c almo,pherie visi bilily impamnent downwind ofthe facility eompaccu wilh a

pri'lme conclilion. Ahhough lhc predicLed amounl of,uell pOlenlial impact from ammonia slip emissions

has not been determined, il is expecLed 10 he ~m"ll in eOmPllriSOn wilh Lhe sib'llificanl anlicipated

reductJon In fal'-ficJd O7<.>ne a,;d improvemenl in almospheric vislhJlity as a resu[( ofIhe overall NO~

emi,"iOrl reduelion.

Delivery of Lhe urea reagent lO lhe powerplanl f"eilily and sLomge ofaqueous mea reagent on-"ilC CCC"le,

the pOle"lllial fur "ccide'llLs, leaks, and subsequent releases 10 air, ground, and surla"" W"ILT immedialely

surrounding the f"eili ly. Ure" i:; ""J~h !cos VOl"liJe than anhydrous or aqueous ammonia, and Ihe."c mks

ale expecle,llo bc manageable. Emergency plaLlnm!\ alld communiry communiea!lons are part of Lhe

m"nagement Illan requiremerll, JOI' such reagcnl usag-e.

UU'"s & Mcllonndl J-,6 Mmnko", Power Cuuperalivo, Inc.
NOx BACr Analy.i. Sludy BAcr Analysis for MRY S",tion Unll 1 NO" EmissiollS

3.4.4

The environmental impact from potential reduction ofannual unil operaling lime by approximately one

percenl dne 10 air prehealer fouling issues as..'<Ocialed wilh SNCR syslem ope"'lion "Vill be to reduce lhe

annual amOUn! (IOns) ofnilrogen oxides emilled, and lhercfore lhe annual number ofNOx Ions eliminated

rd"live to lhe conatant pre-control emi"ion baseline will increase by approxirnate]y one percenl.

SUMMARY OF ECONOMIC, ENERGY AND ENVIRONMENTAL IMPACTS

OF MRY STATION NOx CONTROLS

The economic, energy, and environmental impacts ofeach feasible BACT allernative evalualed for lhi,

S(\ldy is ,ununmized in lhis Sec lion. Tablc 3-18 aumm,,,izcs thc various impacl' discussed in Sections

3.4.1 lhrough J.4_3_ n,e economic analysis el<amined lhe capilal cosl of cach feasible BACT alltm"livc

evaluated and any other l'owerillant upgrnde costa necessary 10 implemenllhe al\(:mulive. In addilion, the

economic analy.,is examined the ol'e",ting and maintenance cost associaled wilh the highcsl-performing

forms ofeaeh fca,ibk BACT allcmulive evalnal,,<L These eoslS were lhen combined inlo the levelized

tOlal .nno"l "0'1 for a comparativc asscssmcnt of Ihc lol"llmplemcnlalion cosl ofeach alternative.

Finally, a, part of lhe top-down analysis, a dominanl controls "ost curve was plolled and lhe unit control

cost for each allernative was evaluated. Two alternatives were on the domin"nl controls cosl ""rve and

lhus were ioJenlifi"d .s Ihe more cOSI efieelive ullem.lives. The IWO BACT NO, control a](ernative.,

evalualed for in"rcmrnlal cosl, energy, and environmental imp;lcls applicable to Milton R. Young Slal,on

Unit 1 were;

• SeleG~ve Non-Calalytic Reduclion (SNCR) combined with a special form ofscparutc-<l overIire

aIr (SOr-A) specifJcally roO" hgnite-fired cyclone boilers (referred 10 as Advancccl SOFA or

ASOr-A); and

• ASOr-A alonc_

Min~kola Power Coop''''li,e. Ine. 3-37 F1ums & Mdlonnell

BACT Analysi., [orMRY SIa~oo Uni, I NOxEmi"ions NO" BACT Aml)"is Study

-----------------------

( ) B g

(2) - E,timaled NO, controllevcl reduction, relalive ro ayr. :md aMu,1 hrd'/T

opennion compared ro pre-control oo,.lino bose<! on

(3) -lnslollcd capilli! cost i, ostimaled forclet<rmination oJ capacity included m

hgniLe rebum opLion are ~23.S61.000 for inmillcd C[

(4) - Annu.l opmlling and mainlcml1lco co'l [or a plIrticuloh i, Ill. high,,,

oonscounv. 12·momh, of opm~onfrom 2001_200~

(5) _ u.velized To..l Annoal Co", An"!l2li",d 1",""led LIIal O&M cost"

1.24&73 ammalizcd O&M cost fuctOT.

(6) _ Average Conl",l CO'1 ElIer:Ijv"",,, (~llOn) is Ille Lo'

(7) ·!ncrelTh."II'ol Control eo" E!!',erivcn= (l>Ilon) is Lbe

(8) _Energy jml'Ool' are inorcmrntal auxiliary oleeltio.1 p.(kW.blSlyr).

(9) _Environmenllli irnpam ,ullllTIllTiz<: expcdcd non·oi, cenlr:llion, Ilk'ly will

inc"""," willl ai,_.=ging oy<lones. Ex""ss umea".,

TABLE 3-18 Summary ofTo -Down B

l''\.CTS ENVIRONMENTAL

IMPACTS

Inerement,l

I.nnll.1 AII~.

o...-er Usage

Emission- Generalion ,,"- R.t. 'l.edl1C~onl"', Noo_Air ToxieAir

Labelll) NOx Comrol AUHualive Ib/mmBtJ.I<W hrsl T Increase Iner""se

E SNCR wi ASOFA 0.355 68,243,017 Fly.,h UBC eO,NH,

A Advanced SOFA (ASOFA) 0_5 13 46,594.605 Flyasb VBe CO

Ba,eline 0_849

, • Al'e,nal;"e l.bel hos !><eo ""i ned [romh; he" ro 1<

Burn. & McDonnell Minnkola Powo, Coopomlivc, loc.

BACT Analy:si., for MRY Srnlion Unil I NO~ Emissions NO~ BACr AnalysisStlJdy

3.5 BACT RECOMMENDATIONS AND CONTROL LEVELS - MRY

STATION UNIT 1

This repOrl prcoC'1lts lhe analysis ofcontrol technologies for nitrogen o"icles (NO,,) for MinnkOla

Power Coopcralive's (MPC's) Millon R. Young Sialion Unil 1 using lhe EPA's "lop-down" BACT

appn>Hch. BACf is an emissions limimtion for each pollulant from Hsource cletermined 10 be

;Ichicvahle using control technolob~es(s) that provide the ,.mH"imum ']cb'reC of emission

recinclion...taking into account energy, environmental. and e~onomie impacts"]'. A BACT review

docs not resull in a percent removal e ITieiCTlcy requirement. The generally acceplcd procedures for

plTfonning a BACT analysis are oullincd inl1,c EPA's draft NSR Manual. The BACT analysis for

Millon R. Young Station NO" emissions was performed in accordanec with lhi.' proccdure. The

EPA' ., drafi NSR Manual outlines five basic slcps Ihat are 10 bc followed in tl,e "lOp-down" BACT

evahmtion. The.,e steps were a, follows:

Slep I - Iucnlify All Conlrol Technologies

Slcp 2 - Elimlll3tc Tcdmic:ally III rc"sible Oplions

Slcp J - Rank R~'1l1aining ()lI\!rol Technologics by Control Effectivcness

Slep 4 - Evaluate Mo.,t Effcelive Controls und Oootlmenl Re..'tllts

Step . ScleclBACT

n,e unal restlll of this analysis is a recommemblion of Ihe BACT allcrn.live and the associated

NOx cmission rule lor Mmnkola Power OJ<Jp=tive's MiHon R- Young Slalion Unit 1. The

emissionlimilalinJlS ror a generation fucility are expreo:sc<l ;n a pounds per million Brilish TI\ermal

Unils (lb/mmBm) basis.

3.5.1 UNIT 1 NOx BACT

In slep one ot'the tcehnology evoluatiun. three basic calegories ofNOx controls for EGUs were_

identificcl: pre-<:ombu<l;on, combustioll, oml posl-<:ombuslion. Elcven basic types ofNOx control

prnce«,es were iclentiued wilhin lhcse three ealcgorios. Twenty four vanations of these elevcn

pmeesses wcre reviewed roravailahility nncl Jpplicability to cyclone-fired EGUs burning North

Dakola lignite. An ·'Juvanced" form ofSeparatccl Overure Air. alone and in various combinUlioos

with Lignile Rebum, Sck..:tive Non-Cal<llylic Reduction (SNCR). Conventional Gas Rebum and

JO Ibid. NSR Manu.l D. I

'.',

'i ':~'<>~:-S~h

Bums & McDonndl 3-39 Minnkol, Power Conpe",livo, Inc.
NOx BACT ALlal....JS Srudy nACT Analysis fnrMRY StatioD Unil 1NOx Emis.:;inns

-------------_...._-

Fuel I,ea" Gus ReburnTM, was evalualed for eosl-effectiverlcss. TI,e cOHt-eITecllvene", analy.;i"

indicaled that ASOFA alone,:mJ ASOFA wilh SNCR were cost effeclive allcTIllilivcs for l'VIRY

SLalioTi Urlill NOx cmmoL The energy and environmenl.1 imp.cL, .,,"lysis for MRY StaliolllJniI

I '" cosl-dTcellvc NOx conlrol allernmive., we, e gencrally insignific~nl.

Ba,ed upon the defimlion ofBACT and lhe re,ullS of lh" BACT "n.lysis, Sele<Olive Non-Calalyllc

I(edocllon (SNell.) 11\ comblllulion wilh • spcci~l form ofseparaled oV~Tfirc air (SOFA) specifically

Ii"lignile_I,ml cyclonc hOllers (referred 10 us AdvaLlced SOl'A or ASOFA) is recommended a, Ihe

Bc>l Avail"bk Control Tcchnulogy I,l' nitrogen oxide6 cm,,>ions from Minnkola Power

Cooperalive's Milton R_ Young Siulion Unil I. The lInil BACT NOx emi"lOn, ralC fllr MRYS

Unil I i.' O.3S5 IblmmHm, determined a, a roiling l2-momh average. ThLS is shmvn in Tahle 3-19.

TABLE 3-19 - NOx Emission Control Technology and Rate Recommended as

BACT for Milton R. Young Station Unit 1

Control Technoloqv and Emission Rate Recommended as BACT

12-Month Rolling Ave~age

Unit Pollutant BACT Control Method BACT NOx Emission Rate

{lblmmBtu)

Seleclive Non-Cutalytic

, NO, Reduclion wilh Advanced 0.-'55

Sep,naled Ow'din: Al~ (ASOrA) '.',

,

3.5.2 EMISSION RATE LIMITATION RECOMMENDATION

Til complcle lhe BACT dererminalion process, lile Con.,enl Decree (CD) require, that '·,pecil'o

cona'ol lcchnologies 10 be insi<.llkd a"d " spooific Ph",c 11 ~O-Juy l\olling Avcwgc NOx Emission

Rule limilalion (lbsIMMBIU)"" (pIlun,b; po, mlllion FlllI) musl bc e,l"blishcd fur c"oh subjecl

emi.<>ion Unl!. TI,e CD also slales lhal "a "30--<Jay Rolling Average Emi""ion Rule" shall l,e

delermine,1 by calculaling an nrilhmelio average Ill' all hourly emi,sion miLo in Ib:>IMMBlu for lhe

cun'enl Operaling Day anJ lhc previous 29 Operaling Duys. An,,'" 30-<l"y Rolling AVC"T"ge

Emi<siOLl ROle shall he calculated fo~each new Operaling Day_ Each -,O-day Rolhng Average

EmisslOn Rate sh,dl include slurlup, shutdown, and Malfunelion p,-nOlJ> wilhin cuch Operating

Dayn"_

"Ibid footnole ",.nlber 1, I"",graph (,(" page 20.

Il Ibid footnole number 1, P,,,,graph 5, l"ge4.

IvIinnkolu Powcr Coopcrulivc, Inc. 3-40 B"m, & MoDonnell
"

...~.

":"t'~

111'

"~,tiN,'·

"" ': ',), :p"

{i'if'

'''.',,',}'{

":'/,,;

"~!' '~'i'~''('' ".', '.\ '\' ,~,:,

'i'"'" 'j(,' .' ,,( . ::: ".;: .- ..,!,,1

. ,', 'j , -'

"

t~t'

,'1.~\';~ ,h1'

.:;1"~;'. .. ,.~~!(',

, '~""" , '"",' :.\i:.:r;,-/:, ,"w;," , ,<;.,

''''",'''

< ~':'f ...~,Ci.:

' ,," B-i'

i:,t!'f.::

""

'-,.,f~;

::·i~t~~: Ai$'

~5A' ,",'l"

, ,\,",,,~ .. ,,,,~., .,"i,"i:t'-

'<tir.'" '''.,i'' , ' ,~",'

,~. ," ( ': ,~;l..1· " 'i~r

,:;~~

'll!" ""~, :';~$;;

;);~

,i':I~'

,,'f ;,<

',,"

:,~':0~;~\:\~':,/, ',"ii,: , :,;.\,,-,~, ')/'1 :'<:",~,~ <,'·.B', '-·"!\j1-!..t~;: i"'A' ", c""", I' ::,~:kW,\':'\',

!,'!;''';~':::'~;::-,1'

iA~'::ii\l',<", ",-:::,' !;'i'f~k~Y;" \'ii!>' "'';-'1,c.,;,'1,,' ,~,,; r""''''',,,,·,,, '""", , " -,V,' ", 'l<.:; -"::'N. '"-;{':~";':;""J!l:- .- ':;~~-" I ";'...'Ii,' "'1I~"i" -,'", i.'t~\ ! ,~';~'",'.' 11$" .',il \V1,(':,;":, , 'j;~'

!k"\:'&l··I"""'······"!i;{ :' '<-" ~'~. ,," ., --.( li:~,,"f." " ~,>:,,;)~:<,t "~,." '. i"" '»: >,

' I'}§~~.' ~/ ::V ':' J0>, ,',', :....~, ,,' "'." >';.:,,~;,

:--~,,:' "":"{'''';'''~t ,{.j, ,~, '#i~~;:, __ ,';,'~~-ii<' ','"'ii, , "" ""'.", ':-"~;~ "j ,':;,',-")1.-, ,~~",~"",: "'h" ,c:';:,'£j', ""." '~"", ""cr' :,¥gji:'"'JC'·;',.::'\t: ,-'k"-\~~ """":""\• I'~~~ ""-"',"M,

:""{'~"I:~('"""';[i!i!.\).; ",1"" 'J';;"" ',*",

;"'M .,~""" ':it{:,1'1, "'~' ~:>,:: " ':,:' t~·, , ,', ""~"''<'' ' ..,',". ' "1<::'. "~":::" '" _,r,",,' :'ii.':t' {-1':>" <',}i1: :'"'<'!J~''' ".','; :':~,1:0~£j<,,; >~;;';' '-,o""';"'I.i>.C" ' '<rJ !<4{fq,'\1\~}. ,'.;',~!L ""};'~'~"W'" :' "::'0:;,, '"V·'' :I': .' '"_,, t-%Jj}It~~\ ',-.,s~~::

:{~t0l~,\,::<:b;~.~, ',:,,/,;,", ~""'~ , .,"'i" ',".,:,:.-:;:);:;:,: ,: 2':;" ' , """."W .' 'h, :" ""f W"~ , ',:., ,,' ""'{~"\'i:l, ,', ',,':,\' """'\}i""" , ~:::.f'?t:~,:c' ,,,;; ,; :~::,;: t>,,,,

"<,,

.(

, ;,"

.-;: ,,',

'i:~J': :,:~" ,

;,'

':'~'" ,c. ,.. "v

;\':,.

.,. "~

:'.',.:':,

"'..,;~'

',".'

,;J

.,'" ..,

:-','::::'

',~>;,.': ',~ ,;.'

':'~:;:

'\\i'

:,(;'

',;}i:,'

,:~~,;
NOx DACI' Anal}"i., Srudy BACT Aual}"i, lor MRY Sialion Unil I NOx Emisoion.,

A r~eenl SEGlJ proposed PSD permit has included" uefinilion "fsl:rrtup a, "the period b~ginning

wllh ignilion and lasling ULllil Ihe c'luipnwnl has reachcd a conlinuou, opcml mg; level "00 opera/ing

p~rmil limils"'". Simibrly,,, shuldown is defined as "lhe period b~ginning wilh Ihe lowering of

"<Juipmem from busc load and lasting unlil fuel is no longer added 10 Ihe hoiler and eomb"sli"n has

eea"e,l"". Based on Ik n;fel\-"nee<l definllions or a Slarlup peL'lod und u ,huldown perioo, the

ammmt of lim~ required [or" SEGU's load (boiler Sleam OUlp'" Or generalor eleclrical OUlpul) 10

Increase Ilcyond such minimum .,mmi"uhle opcmtlllg level, ean be considered p'lTl of,wrtup evenL,

if the SEGU " typically b",,-Iuuded al full load 01' MeR O"lpUL Thi, is Ihe ease with both MRY

Sialion SEGlk

51aliul" ofSEGlh may he lnhderl us cold, warm, and hollo accounl ror thc amount ofre.,idual

hem remaimng ill lhc buikr "nd ste"m l"rbine equipmenl. The various lypes ofstart, ore depen,knl

upon Ihe amounl of limc lhe SEGU has been out"uf-scrvice (i.e. wilhoul hailer ruel firing or

generator megnw"U outpul). Cold .aarlS have been del1ned as slarts arter lhe boiler has been

wilhoUl fllel firing fOl' mOre Ih"n 72 hOIlT', warm ,"'rt$ or" more lhan 8 hours and less than 72

hOllTS, and hot slarl'; are less ihan 8 hours".

Althoul;h lhc definilion or a :;Iarlup ewnl and tile col'responding s!arhlp period IS not required by

lhe Consenl Decree, defining slurl-llps is recomme~ded. 1"l1i, helps to address !he speoi fjc emission

limilllion., during Unit slartups at Milmn R. Young Slation and determine lhe imp,,"l ofsllch

operations On 3U-day roll ing average No" "mi",ions. ['or Ihc purl'0;;~ of lhi, NOx BACT analys is,

a Unil Slariup was deJined as Ihe period from inilial fuel combuslion lO lhe poinl in lime when:

• the measured IleallnrullO the boikr on a 6-hour rolling avel'age b,,"i" is greater Ihan Or equ;]l

lu 250U m,llion BTU/In- for Unil 1; or

• Ihe amounl of lime reported for rhe longesl individual Unit 1 slartup period dming aclual

opemlion belween January 1, 200 I and December] I, 2005 elap.,es, whi"hever occurs l1",r; or

• [liel firing is rli,eonlinued prior to ,ati.,Jying ~ilhcT previo,Js crilcria.

This 'larhlp definil,on Jor MRY Smliou Uml 1account, [or "ondi,i01l, where eyclone refraclory

malerial._ repbtt,] during boiler overhaols must be cured by e.~lcnded low-firing healing cycle.,>

,. Do,cr1 Rock Energy Cenlcr (A7P04--01) 1-'lOp05CJ Pl;1l Pon"il Condilinn<, page 7.

(IJ lip:!Iwww.epa_goy/rcgion09/airipelllliLlJ...orlrock/llJ1<.mliL)

J7 Jhin, p<lge 7.

" Applicalion for PrcyenliOIl of Si£uilicanl I)denora,ion Pel mil fnr Ihc D'Sert Ruck Energy Foollily,

Docnmelll Numl>or 094 17-JG0-250RI, May 20114, page 5-1.

MillJlko(a POWeI Cooper"lwe, Inc. BUlm & McDunneJl
HAC[ Analysis roc MRY Statim' Unll I NOx Emissions NUx !lACT Atlillysis Slody

nnit conlmls arc upgr-aded and mu,t be "djusled during low-lo~d opemtion, or for boiler feedwaler

qua lily 10 improve after boiler mainlenance h"s been perfonned Ih"1 "ffccls lhe inside' of lhc

Wlllerw"ll und superheated slearn tubc". II also allows for a failcd or inlerruptcd start <equence

which Can require consi<!cwbly less Or more time 10 elapsc lhan an averal;c s\flrlup duralion.

Analysis orMRY Slation Unit I opernlion, d"la from 2001 through 2005 revealed:

• ThLTC "'~'Tc 60 lolal slartups in Ihc five year period;

•

•

Minimum slartup was 10 hours ror a ··hot" slart li>lIowing a boikrmasler fuel inlerruplion

(Vnil "[rip");

Mnxirnum Slartup wilh an exlendcd ramp-up period lmlil full load was reachc-d was 61

hours.

,'.

'" .

Unil] had a SLart_up Ihat began On June 27, 2llO5 Ihatlastcd for 61 hours_ This startup included

inilial firing in the 5" hour of6127 (0500 hours being Ihe beginning uribe slartup period), and

which endcd "lthe end oflhe ]7'" hour (i.c. al 1800 hours) On June 29", 2005 upon reaching a

l;cllc,-awr output of 245 MW (gross) rnlher thon a 6_hour average heat inp'" rale ofmore Ihon 2500

million Btu per hour.

TI,ere are cerlnin hoiler operaling conditions thai need lo exi~1 before Ihe BACf NO" control

Icehoiques and teclmologies can be effeclively operated:

1_ The rurnace ga, lernperlllurc in lhe region wbere Hurea reagent solution is lojeoled for

SNCR-b-...'>ed NOx control musl b~ belween 1700"F and2JOO"L TIus region is expeeled 10

be in Ihe vicmily oflhe furnace exil, whioh is oommonly defined as eilher lh. horiwnlal

plane extending from Ihe furnaee rear waH arch C·nose") 10 Ihc fronl wall o[lhe boiler, Or

Ihe vertioal phne from Ihe nOSe up 10 the furna"" roof, upstream oflhe gas mletlo Ihe

superhealer lube banks. The gas lempCl"llture (FEGn I"llnl;c in lhis fumace rcbrion is

dependenl on boiler heal inpul rale and cleanliness oflhe firesides of the [umoee walls,

which orrecL, the amoun( ofradiant energy absorbed by lhc wall tubes an<! lransferred 10

Ihe waler within.

2. The numbers ofaclive cyclones and conlinuous coal firing rales musl be enough 10

establish suffioienl:

a. coverage ofmollen slag on !he actively-fired cyelone barrel surfaces and drninage of

lhe slag from the bOltom of the boiler; and

Bums & McDonnell Miruokola Power Coopcrdtive, loc.
NOx BACT An.lySlS SIUlly BACT Analy,is for MRY S[",;on Unil 1 NUx Emi.~"ons

b. combustion air/low through lhe aclively-fired cyclone:; 10 ..llow a pOl1 ion \0 be diverle<l

to Ihe scparated owrlire air sysLem abo"c lhe amountrequlT~-.Jfor idle cyclone cooling

and SOI'A noz:-dc cooling.

As prevIOusly discusscU, [unlace eXli n",· gas lemperam",:; (FEGTs) win ne"d 10 be mea,urcd or

delermined empirie"lJy during opc",lion oflhe MRY St"lion boile" in order 10 be ahle 10

etleolivdy control NOx emis",on' ming SNCR lechnology_ Th,- 'ksign and opwLlioll oftl,e SNCl{

oy,lcms "t MRYS for CD Pha,e 11 em,,,ions eont, 01 .'],o"ld inclnde fealures Ihat aecolllrnodale

cyclone hoiler :;I"rl"ps "Lld ]ow.10"d operat,oLl Wilh "dc"n" or '"dirty" boiler heallronsrc"T sLlrface"

"s ,nOLl n< conditIOns OCCUr Ihlll "re lechnically procll"able, i.e_ w,lhin Ihe SNCR 'yslcm vendor's

recomm~ndedopemllng guidelines, os ",..dl "s fulT-load con,hlions in orde, 10 mil1lllli7-" No",

Tile amounl and duration nfsusl"inod boiler henl inpLJI required ill eSl"blish lhe operaling

condilion:; dcscnT:>ed In item 2 "bove J" more ,liflicu]1 10 1" eci.,ely ,!ctem'ine. Lignitc heal conlenl

v"TillbiJity ""d iLlahih ly 10 "ccuralely <1clermine Ihe acmal aiTff"cl rolio on cyclone-by-cyelonc

b"sis in real-rime, "nd Ihe slaggi"JS lind fouling characlerislics of lhe lignile "sh, came (and are

expected l<) ~onlinue to cause) ,!lflicullie.' Willi Sl"bk eombusIion performance. The minimum

nriJlg r"lc~ of the MRY Slalion boile," required to ~lIccessjilT1y inilillte the effedi\'c operation of lhc

SOFA sy"lelll are 'pecifie 10 eac1, i"dividulli bo'ler, aLld a,e nol currently known. Due 10 Slleh

Opel aling pr<Jblcms "nd emi,;-,wTI eunlrol limitalions, Ihe abihly 10 dkclively Iimil NOx eml"JrIn'

during slarlup periods "nd low·lu"d operalion following implemenlalion of advanccd SOFA (CD

Pha"e I conlrol) "ndfor an SNCR system (CD Ph"sc II conl,ol) is "nccJ1ain_

Bcoause lhe,e Jre expecled 10 be minor short lerm variation' in operaling condition" durin!; slartups

where MiLlnkolll hll' not, in fae~ m"lcTIally ehonged nny of their normll] slnrtup oremling prneliccs

and crileria, a margin belwcen lhe Jll-day rolling average "lendY·'~"lte NOx """",ion rote (which

doc, nol include lhe impnct, ofslartups) anu Ihe proposed 30-day roTTing a vcrage NOx ellli&sion

pennit lim' t lhal includes slartup emi"ions is recommended. 1bi' role considered 'eco!;nized

operalion,,1 factor" and equipmenl de"ign" apphcd 10 sleady .'laLe eondilinno wilh suslained output

close 10 maximum continuous eapaoity ralings. The recommcnded 30.day Rolling Aver"gc NO,

Emi"""ltl Rale pC1"nnl limilation exclu,ling Ihe impact ofsl"rtups lh"1 reneols BACT Illr Millon R,

Yo"ng- Slalion Unil I '" shown in lhe lable below.

Mum!."I" Puwcr CO"l"'rmive, Illc. 3_46 num" & McDonnell
BACT A".I}~i, for MRY Sialion Unit t NO~ Emission'

--------------- NOx llACr Analysis Sludy

-------- -----

.- ,.,.,

TABLE 3-20 - Recommended NOx BACT Control Method and

30-Day Rolling Average NOx Emission Rate LimitWithoul Startups

30-day Rolling Average NOx

Unit Pollutant Control Melhod Emission Rate Limit

Excluding Startups

lib/million Btu)

Selective Non-Culalylie

, NO, Reduolion with Advanced 0.J60

Sepurated Overfire Air IASOFA)

This recommended BACT 3D-day NOx emission ralC limit is hased upon a hisloric prc-conlrol30-

day baseline avCrdgc NOx ernis<ion rate of 0.884 lb/mmBlu for Unil I. The ha.seline emission was

delennined from the 30-eonseculiv~ day period with the highest hisloric unit NOx emi"ions rnte

reporled lor aotualopcration bctwceo January 1,2001 and December 31. 2005.

A recommendcd BACT 30-day NOx emission rate limit llmt includes !be impaol ofslartup

emissions should be suitably highc, soeh lhm opemtion consislonL Wilh lhc lechoological

JimiLalion". mnnulaolurer's specifications, and good cngineering and maintenance practices to !be

extenl praclicuble fur the MRY Slalion hoiler' would not resulL in an exeeed",ee (violation) ofan

enforceable JO-dayroHing; average NOx emission permit limit

For MRYS Unit I, the recommcndcd 30-<lay rolling average NOx emission pennit llmil rale mal

includes the impaci of"Iurlup' is bascd upon rccogni~ed operalional faclors and eqoipmenl designs

thai innuc"TIce wheiJler lhe startup emis.'ions resull in highc, 30_day emi""ions compared to normal

conlinuous operalion without Or cxcluding such stllrtup peliod,;

1. The uncoilirolled cmi"ion rate (i.e. withuot scparaled OFA or SNCR in oper;ltion) and its

variabililY during opemlion Irom a cold, wann. or hO[ slartup up to and mcluding maximum

eonlinuous raled oulpul;

2. The opefming oonditions lhallU"e required 10 exist for the selecled NOx BACT conlrol

techniques to be initiated and be effeclivc; and

J. The efTeetiveness of thesc two panicn]a, control techniques If invoked al kss-!hon"MCR

Sleady-sLate operating conditions.

4. The numhcr o[slartups and the,r range of typical dumlions per 30-day period lime frame.

Butn, & McDo'mell Miaakola PoworCoo[>Crativo, Inc.
~(h BACT A,,,I}',i., SLuJy

R"·i.,,,J 10, 1);:'.000

----- -~

Th~ Jun~ D-29, 2005 <Ianup was ehmen [()J' additional evohWlio" a< tho ,(,,[I-up fOf )vJRY SI>llion

U"it I.

An ineremenlal odjmlmenl 10 Ihe proposeJ 30-day rolling; llver~g" ,Ieadj' -'lale u"it NO., llACT

em!"ion rate wilhou! stamLp5 or 0.36 IblmmFllu rnr UniIii, recommeLlded for Ihe 30-,lay rolling

Jverage NO.• emission permit limiI retiod< "-, detl"",1 nnd arplicd 10 Milton R. Yo""g Sialion.

Thi, is >lmum"i,ed in Ihe miJle below.

TABLE 3-21 - Recommended BACT 3D-Day Rolling Average

NOx Emission Rate Limit and Startup Impact

30-day Rolling Average NOx Impact on 3D-day Rolllng

Unit Emission Rate Limit Average NOx Emission Rate.

Exc:[uding Slartups Limit Due 10 StartLips

(Iblmillion BtLl) (Iblmillion BtLl)

, 0.J60

I

10.041 ror ,tJm1r

Thi, rccommeaded adjustment m the IlrOpo,ed 30-da)' rolling average <wJd}'-stJIe NO, nACT

emission ,"Ie limi I wilhull! slartups is b";~d upon average hi,roric pre-eolllrol NO.\ elllissicll L7LI'"

ot·O_766Ibimm[Jlu for ULtil 1 rCjl(]rl~d fur lhe longe" indi\'id"aIU"it 1 'l:lrILLI' perin,1 dllri\l~ ",Il,"l

operation betwc~n January I, 200 I a"d Deeo",ber .11, 2005. The,e emi,.,in..., uccurrcd duri,,~, Ihe

61-hour June 17-29, 2005 ,mITUr for lJl\il I.

.-'t. l'l-hour rnliing avc,,,.~e [IA(T NU, emission "He limi! applicd 10 ,Ia""p periud, i, abo

['ecommended for enell orIhe !vlihun R. Y OULlg Siniion boilers.

Thi, i, summari,cd in (he ("iJI~ below.

TABLE 3-2.2 - Recommended 24-Hour Roiling Average

NO~ Emission Rate limit During Startups

24-hoLir Rolling Avarage NOx

Unit Emission Rate Limit

DLiring StartLips

(lblmillion BtLl)

, o.no

Mino,ota r"werCo"pcml;Yc, Ino. 3--18 BUlll' & "101)""0011
BACT Analysis rOT MRY Sullion Unil I NOx. Erni,,-,ion< NO~ BACT Analy,;sSludy

- ..-

These emissions occurred during thc 61-hour June 27-29, 2005 startup for Unit 1.

Compliance with Ihe-Ie emission rales would b~ measured at th~ stack ofthe LJni~ verified wilh

Continuous Emission Moniloring (CEM) sySlems in aceord"nce wilh Ihcrcfercnce mClhods

specified in 40 Cr:_R. Part 75, "nd would bc delcrmined on a 30 conseculive Opera ling D"y and

24-consecutive hour rolling average basis, respeclively.

A trial demonstration operating period of 18 monlhs ufier Ihe complelion ofConsenI Deoree Phase

II NOx emission redoetion system inslanalion commissioning al Millon R. Young Stalion is

recommendcd. It is proposed 10 allow MinnkOla 10 demonstratc the aclual oontrol systcrn

capabilitics oflhc comhined NOx BACT emissions reduction syslcm. Operaling experience during

Ihc trial period will:

• confirm steady-slale conlrol perlonnance ofthe eombincd NOx BACT emissions reduclion

syslcm;

• allow determinalion oflhe abilily 10 furtkT control Unil slart·up emissions;

• allow the dClermination of Ihe permitted 30-day rolling average NOx emission limil including

startups, "hutdowns. and malfunclions; and

• ~d<!n:ss the ,peeifie emission limilalions during Unil slan"ps at Millon R_ Young Slation nnd

their impaci on Ihe propo.sed 30-day rolling avcrJgc emi""ion mle limit (without slartup")_

Based upon Ihe .information oblained during the trail pcriod, [inal emission limits Can Ihcn be

determined.

The meanS Ihal will bc employed 10 minimize emissions dUring slartup will primarily be ha,ed on

opera ling procedures, bolh before and. rLer the level of upper fumace gas temperature, and/or he.1

input rale arc eunsidored sufficienllo slart Ihc NOx conrrols and opcr.Jling oonditions are conducive

for effeotive emissions reduction. These could be similar 10 Minnkota's cum-'Tlt MRYS practice" or

wuld be differenl, depending "pon lhe c.pahiljli"" of Ihe NOx controls and their impacls on Unil

OP~T'lions.

Bums & McDonnell Minnkola Powcr Coop<:ralivc, Inc,
NOx BACr AnalysIs Smdy

Referenc"s:

[IACT Anoly,is for MRY S'aLion Unlll NOx Emissions

I. III the United Statcs Dislrict Courll'or The Di,trict OfNorlh Dakola, United SLales or

Amcric" ,md Slate Of North U"kol:t, Plaintiff" v. M,,'T\koLa l'olNcr Coopcwli"c,lnc. ami

SqU"TI: Bulle: Eleenic Coopemllve, Defend"nl", CIvil Action No.I:06-CV-034.

2. EPA New Sourcc Rev;ew Workshop Manunl, Prevenlion ofSijlnifLcJlll Delcr;",aIJon aod

Nonall"inmCul Area Pernullillg, Draft Oclobcr 1990 (The uNSK Munuol").

J. EPA Docket OAR-Z002·0076-0L\46 T~cl",icol SUPP0l1 D(JCumem for HART NOx Limits lor

Jokelne Generaliog Units Excel Spreadsheel 6/1 512005, posleu on lheir wcb,ilc: [rom

EDOCKET at

hIlI';IIuoekCI.e po.govlcdkJlubldolEDKS to [[]IcmDc luiIV, ew'Iobj co lId ~O 90007<14 SO 84562 b;

Ihi.' i.' ae..,oeioled wilh EPA Acid Rain hOb'rum C1eaLl Air M;JTk~t" Divi"ioll, Tecll"ical

Supporl Ducume", - Melhodology I'or Developing BART NO, l'rc>umplivc Linlil>, June 15,

2005,OAR-2002_0076_0445_

4. EPA Office ofAir Quality Plarmmt and Siandards (OAQPSj puhlicat;on EPAI,1521ll-02-00I,

Scclion 4.2, NOx Controls- NOx l'osl-Combll"lion, Chapter 1 - Seleclive Nun-C"I"lytie

Redllcliun, d"leu Oclobcr 2000, posted allheir webSIte: hltp,llwww.epa.gov!ttn!cJtcldLrlfcs4-

2chl.pdf

MinnkO~1l'OwcrCO"l'c"TIIl1vc, 1m;. 3·50 Bum, & McDonnell
,.,-,

APPENDIX A

Technical Feasibility Assessment Details for NOx Control Technologies (A1)

U.S. Coal Cyclone NOx Reduction Projects Summary

With Retrofit NOx Control Projects' Technical literature Summary (A2)

AI'PENDIXAI

Toohnical FClISibility Assessmcnl Dda~, fOI" NOx Conlrol Technologies

NOx DACT Analysis Sru~y

A.1

A.1.1

Technical Feasibility Assessment of NOx Control Alternatives

Pre-Combustion Fuel TreatmenUSwitching

,...

Fuel swilehing can be a viable melhod ofNOx emission rc~uclion in certain ,ilWllions. Olkn, coal

combuslion facililies are construcled 10 lake maximum advanlage of lhe particular combuslion

charJclcnslics ofa specific fllel. In lhe Case ofMRY SMion, the Unit I and 2 boilers were designed and

constructed ,,.,-cifieally lor firing North Dakota lignile, which has a fuel higher healing value (Blullb)

approximalely 20% lower ,han typical Powder River fiasin (l'RB) cool. A cyclone-fired boiler

(Oltertail's Big Slone Unil I) Iha, is similar in gcometry and steam geoemlion design lo MRY Slal10n

Unil2 fires PRR coal. Based on a comparison of available emission data belween Big Stone Unil 1 amI

MR Young Unil2, lhere is no expecled reduclion in baseline G.e. uncnnlrolled) NOx emissions from

swilching 10 1'ItB from lignile al Milton R_ Ynung Slalion.

Conwrsion o[Millou R. Young Sialion Unil I boiler 10 fire PRE coal is technically possible. II is

expecleulhal major planl modificalions will be required. Rail service is nol prcscnlly inslalled at lhis silc ,

so the addilional opcmlional and capilal costs to bring in Iargc 'luanlilie., of PRE cnal will be "ignificanL

Invesligaliou of!hc sp"Cifie source, dl"rnnCe, and cosLs for supplying nccessary qunntilie" of PRB coal via

rail or lrocks to M_R. Young slal,nn has nOI hecn perfonmiL With zero baseline NOx cmisslOns

reduction c"pecled li·om application of fuel swilching, lhis ahernalive will not be economically

compelillVe Wilh olher NOx conlrol ledmologie< lhal offer belter resulls ror a much lower combinalion of

capilal and operalional eosLs. Although fuel Swilching is technically fea~ible, il has not heen consldered

further as an effecllve NO" emissions conlrol oplion for MRY Stalion Unil 1 boiler.

A.1.2 Combustion Controls

Combustion conlrols comprise !he mosl num,.nus calcgory ofNOx emission rcuuclion lc-chnoJogies.

These lechniques cmploy methods lhal reduce lhe amounl ofNOx emissions crealed in [he combuslion

zone of lhe boiler prior 10 e>JJausling lhc /lue gases from the furnace (up>;ITcam of the eonvcclive heat

trausfer zones). The.e coutrols resull in fcwer emissions 10 almnsphere or lhal may reqnire subsequenl

rccluClion from addiliun"l applicahle comlmslion andlor posl--combuslion lechnique,.

As lhe boiler>; in queslion were desigoed for firing North Dakola ligoile fuel, lhey wcre furnished wilh

suilably-sized furnaces "nu bmiled hack-end economi7.er heal transfer sort,ecs upstream of Ihe air

prehcalCTs. This provides high lemperalure air 10 aid [he evaporalLon of excess mniSlure from lhe crushed

coal partides in lhe pre-comhuslion drying systems, and long residence times lor solid and gaSC(lUS fuel

MmnJrola Power Cooperalive, Ino. At· t Bums & McDonnell
NOx BIICT An,ly,i, Stu~y APPENmXIII

Technical F,-<",biJity A''''>SIUenl DoLail, for NO. Conlrol Tcchnologio,

parlicles 10 bum es.,ent'ally to colltl'letioLll'rior!o kuving Ihc lilmace,. The laller fe"-tnre i, ~'"P"eiajJy

advanlageon., for applying "nrio"s rorms "reombuslion moJili,'oti"ns which are cond<Jcivc in rcducJng

NO, emission.'.

A.1.2.1 Basic Combustion Improvements

Combllslion improvemenls a, e commonly·:>pplicd Ic"hm'l"'" wo,ch may produce mode:;! im:n-mental

NOx emi.""on, rc<1lJCI10n,_ In Ih"iT mO~1 basic fonn. these lypically pwv,d" improvcmcnls to com],uSI'OJl

~ir now dislribu('on, mC<lsun'm"nl, "nd prcssure. logclher wilh Iilel now mca,uremC'TI1 and metering, [0

promole consistenl combnstion ~eJi(" mane" by Imming rud w,lh more accuracy ill main l<lining a desired

fUel/aJr ralio.

Thc," improvcm''TIl>; m"y lIUOW, or bc combined with. the praelice or,,'vcral olhcr NO" control

lechniqucs, SqJaTIllcu ovcrlirc mr (Jiscll3Sed helow), "',lh or wilholll "low cxec,," "ir" (LEA), bLJTTJcr,

out-<If-service (BOO~) and h,"sed firin~ (IW) opcrnlicm of Ihe cyclone" e"use a decreasc in lhc ralio of

comhustlon all' to iilel supplied to lhe cyd"n"" (burners), Ihlls reJucing the amount of lhermal NOx

"J11iSoion~ produccr! J"ring "QmhuSlion, Thc "mounl of p"lenli"1 NOx em,,,ion rctluelioLl achiev.hlc

from lhese b",;" lechnique, is highly-uependenl on the speci tic IYpe offiring, fud. "nd condilions which

apply 10 lhe b"iler(,) heing, reviewed.

M"king lif,",ile ,Irying 'yslem air aJjuslmenl' and adding improvements 10 lhc boiler comlmSl'un controls

anJ reJncing combuslion "ir inplll" have "Iready reduced uncontrolled NOx emi",ions al Milton R.

Young ~Ialion boilers "pproxml"lely 10%. l'uI'lhcr inc"'me",,,l ,mprovements flOm add,lion,,1

eOlllhu'liorl conl",l, Ihal allow operalion with mouesl mnounls or cyclone oir .,raging, "imilar 10 Ihe err~cl

or" sepor"ted overfirc a" "y<lem, OrC po,;,iblc, Incremenl"l NO" lwis,;on, reduclions are expecletl from

slll'h impr(lvcTllenl, bClng 'ncorpowle"l inlo "nother fea.<lble "ltemalivc, ~uch '" scpar::Lled overfirc air.

Tnis altenmlive W"S not considered"s a srand_alonc uplion ror odr!ilional NO" reduclion ..1Millon R.

Young StatiOLl for lhe Uni! I hoiler.

A.1.2.2 Low NOx Burners (LNB)

Low NO" bllmcn; (LNBs) or voriou, <!c,i,,'Tls have heen commonly applieu 10 pulveri7.ed coal-fireJ ulility

and mduslri"J boilers for morc than le'TI years. llowcwr, lh~y nr~ not i,,"lalled on cyclonc"fire,,1 GOller.<.

Thi" IN,Imology is ,Il r~a"hI~ On cyclone boilers', and WliS eliminale,1 from consi,lcrnl,on for .dd'llO"al

NOx rcduclion at MillO" R. YolJng Sl"licm Unil I's hoiler.

[lum, & McDunndl Al-2 MinnkOla Power C"opcr,Uiw. Illc
APPENDIX Al

TochnioaJ F~as.ibi~ty A""ossmem Detail, fOT NOx Control Tecllnnlngic'

A 1.2.3 Separated Overfire Air (SOFA)

NOx BAG[ An.lysis Sludy

Sepnrated overlire air (SOFA) is a combustion-related NOx cmission rcduclion technology frequentlyapplied with and without low NOx burners to utility .nd indmtri.1 boilers for more lhan twenty live

years_ Separated Overfire Air (SOFA) is an air-smging NOx emission reduclion combustion teclmiquc

that is typically based on withholding 15 to 20 perccnt oflbe lotal combustion ~ir conventionally supplied

to tl,e liring wnc. Thc diverted combustion air is then injected in the uppcr [umao., where combustion is

complded_ For typical cyclone coal-fired boilers, th,s invotves diverting approxirlliltely 20 percent of the

secondary combustion air, forcing lhe cyclones to ope,"te fuel_rich. Starved-air combuSlion causes fewer

NOx emissions to bcproduced.

At k-"Sllhirty nine existing cyclone-fired boiler" firing eastern biluminous, midwestern bituminous, and

weslem subbituminous ("Powder River Basinn

) coals in unil' ranging in size from 50 to I 150 MW, have

been retrofillcd with cOUllllen:ial SOfA since 1999. A sumrllilry ofscvc,-al of the first SOFA (amI rcbum)

retmfits to cyclone-fired boilers is described m published tcchnic.1 papers'·'. Cyclone boiler rctrofit

SOFA installations <ITC included in the EPA's BART lechnical support dooument' and listed later,in

Appendix A2.

A hasic form o[scpa,-ated overfirc air (SOFA) can be applicd and in.s~Jllcd on MRY Station Units 1.

Therc are polenlial irnpacIS and limitations uniq\lc 10 'he firing or-Nortb Dakola lignite in cyclone-fired

boikrs that should be recognized as part of this emlSs,on reduction technology application.

Kcy a.,pects ofsuccessfully applying nnd opera ling a separatex! overfire "ir system un a cyclonc-fired

boilcr are the ability 10:

• Accurately measure the fuel heat input r"tc (BnJs) and combuslion air inpul' On a real-time,

individual cyclOne 11Y cyelone basis, to allow the ability to determine and control the dcsired air/fuel

mIlO, especially when "starved air" (i.e. substoichiomelric) combustion conditions are required_

• Mainlain adequate molten coal ash (sl",,) formalion and now within the barrels and slag (ar-'_

The dcgree to which the cyclone furnaces can bc operated with less than lheoretical (SUbSloichiometric)

combustion .ir directly contributes to less NOx formation and further in_furnace emission n:duction bUI

also risks solidifioation ofthe mohcn coal ash. In the case ofMRY Slation Unitt boiler, cyclone

combmlion must be sufIicicnlly air-staged 10 n:ducc NOx emissions while releasing enough he;)t to

con~nuc to melLlhe fuel ash so lhat it 110ws effectively within and from the cyclonc burners.

Minnko13 Power Coopcralivt:. h,e, AI_3 Burns & McDonnell
NOx DACr Analysi, Study APPENDJXAI

Teclmio.l Feasibility 1\.,,,""'""1 Deloils for NUx Conlrol Teohnologic,

In lhe oase ofMIlY Stalion boilers, lhere i, a sigllllJoanl ml100nl ofvariahility inlhc eornhu,'lible Jnd w'h

componenls of North Dakota Iignile ""ppJied from the cll'Tenl mine near Center, NO. Aoaly"is ofseve,.."l

[mndr",l cu,,1 feed san'pk> L,ken "irnullaneously ji'om mulliple cyclones ofMRY Station Unil 2's lJOilcr

ITve.led that ll,o rrr"ximum dilT"ren[ial or [l,e ligmle healing val",," from cyclone-to,cyclone w"sju"

over 12% of Ihe average healing value of "11 lhe sampk". AssUilling all opcruling case ooctJrred wkrc

Ihe maximum cydone-lo-cydunc di ffererltJn1 he;Jling valu~ W;JS fur lwo cyclone" m Ihe uppo"ile enu, 0 r'

Ihe fuel he;JI eunlent rang~, Ihc'" would be" plus Of rnin,,> 6% vari~lion in f"ellll'''1 contenl fur eid'~r uf

nl<' individual cyclones frum the oV~nill "verage. I[ Ihc ues" ed "v~rng~ cyclone "ir/fu~1 (sluichio",clrie)

mlio wa, 0.95 when operaling wilh alr-s[Jged cyclones a""ooi_[cu wilh separaIed ovcrr,rc "ir, and Ihe

amouLll of,ccQnd"I)' eomhustion air 10 ~aoh eydon~ wa, "'1",,1, lh~rc would k a "IOlchlOm~lrie rallo or

Jpp,oxlTnalcly 1,01 in one cyclone and a ,'IO,chlOmetfic ralio "round 0.89 '" anolhcreycJon~a[ lhe Same

lim"..fhe modes(]y air-'l"ged cydon~ would pI odu,,~ higher lhan averar.c NOx CTJ1lssioJls. 'j"h~ deeply

sl"geu eyclon~ would produoe l~", !han Jver~g~ NOx elJll"",ons alld pOlenlially in,ulliciL"Il1 amounls of

heal releJs~, and raise Ihe ri.,k of,0Ji<lifying the fuel ash "0 lhal il accllmllbles will,in lhc cyclone ball'~L

Thi, could T(,,,rll in firing ~u~ili"'y fu~1 oil in lhc de~ply-Sl"geu cyclone or taki"g Ihc boiler o"l-of~'~r"ie<'

10 remove lhe pluggnr.c. Neilher ofthe,,~ eondllionl- lS ,lcsirabl~ l,eo~u,", llwy [(·,,,11 in low<:r cmi.",om

r~moval pericrmanee ,mu high~r opcT"ling cose,. Thus. du~ 10 lh~ variabilily ofthe fuel heat conle~t ~nd

the complex beh_vior o[ li~ni le aoh when ~xro,e<llo hJgh kmpcn'lures, lhe exlent of aTr-slagrng and thus

Ihe lewl ofNOx control in MRY Stalion hoikTS is ~xl,"el",llo b~ 1J10d~st wl,ile firing lignitc coals.

ln order 10 pOle[\linTly nchi~ve lower NOx emi,<sion mles w,th morlcotly "ir-slJged cmnbtlslion [or MRY

Slallon boiler", addillOnal comhuslion imp, ovelllClIls can be 1l1'I"lled. On~ potenlial irnpro"ernc"JJl is 10

LJnplCrll~"1 " unique form of SOFA for Norih Dakola-lignile-fired cydon~ bOlle". This includes

relocaled lib'llile doying syslem venl pOrlS. This will bc rderred [0 "-, ·'Advanced SOFA" (ASOFA).

Tl'<:rc arc several de"ib'll challenge$ anlieipal~d for impkmenting the advanced versioLl (wi[h Ihe

descrJl>ed porl rcloealions) ofseparated OFA. These ar~ khcve,1 10 be solva!>I~.

nOlh lorn}> ofs"parat~d ovcrfin: air as a COmbllslion-rd"IGtl NO, oonlmll"chniqllc are considered

fc-asihl~ lor apl'li""llOl1l0 Millon R. Young Stalion cyclone bOlkr", Since lhe advanced SOFA is lh~

highcsl-pcr[omling I'lnn of lhi, leclmology, only Ihis ASOFA version ofthe allcmJlive w~o co",id~rcd

[or audilional NOx r~dlJclion al Milton R. Young SI"lion boilers.

MlIlnkola Pow~r Cnore",live, Inc,
APPENDIX Al

Technical F"",ibiJi,y A""e",mcnl Del.ils [or NOx Control Tcchnologies

------------

NOx BACI' Analysis Study

.,'-'

Another fonn ofseparated overfire air being markcled commercially is "Rolaling Opposed Fire Air"

(ROFA)_ For ulility applicalions in Ihe United Siales, this ha' only heen applied to pulverized coal-fired

boilers, prim,nily langenlially-fired uni",' _ 11 is diffcrenl limn basic SOFA in thai il includes a hoi air

booster fan, and injects Ihe overfire air in an offset rashion from opposite sides Oflhc furnace al high

vdocili~" with mulli-pon nOZl'Jes localed at high eh:valions relalive lo Ihe lOp burner row. Th~ vendor

(Mobole~ USA) claims ROFA maximiz..:s air-~Laged in-furnace combu.'lion NOx reduclion while

minimizing negativc impacts on carbon monoxide and flyash unburncd carbon.

While Lhis varialion ofseparaled overlire air could pOlentially bc applicable to cyclone boilers, i1 has nol

been markeled 10 Serve such applications. Because cyclone boilers do not reqnire Ihe addi1i,!n of hot air

booster lims for SOFA, Ihis technique i, nol distitlct enough from basic SOFA from fimclLonal and air_

staged cyclone NOx reduction performance slandpoinls 10 W~mltlt individual cOtlsideration. ROfA

ledmoJogy lacks demonslratd cyelone---lired boiler experience, ~nd thus was oonsidered infeasible and

not included in !he conlrol effeolivencss and cost--effectivene'" sections of Ihe main report.

'-A.1.2.4 O:Kygen-Enhanced Combustion

A supplier of liquid oxygen (Praxsir) has developed a meLhod ofreplacing somC of Ihe combuslion air

-supplled lo Ihe burnen; wilh pure oxygen. Combuslion aLr, which i' normally input Ihrough (he sc"Condary

'air system duclwork downslream 01" the forced draft (FD) fun lind air healer, is supplemenled wilh pure

oxygen dircClly injected inlo thc burners_ Oxygen-enhanced combu,tion (OEC) can reduce boiler NOx

emissions =ulling from .• Ihcrmal NOx", a reaction of Ihe nitrogc"ll in the combuslion air admiHed to the

burners wilh tho available oxygen in Ihe air in lhe name or peak lempcratllre region, oflhe fuel

combuslion process. The use 01" pure oxygen instead of ain-educes the availability ofnilrogen from Iho

air 10 bo oxidized in Ihe high Icmpern1ure regions. Ihus reducing rormation of lhennal NOx_ This

lechnique has only been demonslrmcd in a boiler with pulverized fuel burners firing biluminous coal'_

The lack of adequate experic"llcc On any cyclone-fired coal-burning boiler, on a tcmpo""ry demonstralion ,

or permanenl full"scalc basis, and for a eoal_fired faeil ity of Ihis size, precludes coosideration of oxygen·

enhanced combuslion atMRY Sialion Unit l's boilcr. This is deemed to be infeasible technology at lhis

localion allhc present limc.

MinnkOla Power Coop"rolivo, Inc_ BunlS & McDonncH
NO. [lAC!' Analysis Sn1dy APPENmx Al

T""hnical Fo.,ihilily Assessment Derails fot NO. COnlIn! Technologies

A.1.2.5 Flue Gas Recirculation

Flue gJS recircul.tion (FGR) h;," bcm commonly applied to coal-flred boiler,. primarily lo inject into lhe

lower furnace. jmt ,h'lVe tlie b"m","", '''Wlic",l from Ihc boiler', economizcr fl"e gas outlel YJa n bol gas

homTer lim. Thi, modifies the amounl and temperatm e of hOl fumnec ga, eilher in lhe lowlT-middle Or

"ppcr f\lmoce ond convecTion heallransler ZOnes. As Ihis flue gos lypically h"s an oxygen conle"l ;lrolmd

2-5%, II limit" lhe avnilabilily of oxygen 1Il a Illgh lemperatu,.e, l'O."il>ly liJel_ric1, lower f"maee zone.

Flu,' gas U'CITCulJtlOn for NOx conlrol i< mO.'t oommonly upplicd wilh gascoos or lJ'IlIid fossilliJcb III

rcduec the high Iemperalores w],ioh OOllverl nilrogen inlhe eombuslion air 10 nilrogen oxides. No

examplcs of using or in'lalling FGR on cyeJone-fired boiler.' s"iclly 10,. NOx e"'L~,inll' c,mlwl we, e

lound in uvailable technicolliternture.

}'or MRY Slolion Unit I 's hOLler, I'GR was origin.lly supplied from lhc oullet ofLhc induced d"'fL f;ms,

but has .,LLlce !leen disconliTlue,] nnd removed. Sinec it i" llol operntionJI on Unit I, and Therefore does

not "ITeot thc polcnlinl pCTform"ncc of ocpJITIted overfire Jlr (in an '"advanced" li)l'ln), il would not he

cxpecl,·,1 10 ""luGC NO" cmissions ifrelll,lalled alone or Ln cocllu;"nli(lTl WiTh 501'A. Allhough FGR i,

technically feoSlble, Ll bas Llol heen com;dere,l further US"n cff,-cllYe NO. cmi,,;,ms control opIion for

MltY Sralion Unit I 's boilCr.

A.1.2.6 Water/Steam Injection (Combustion Tempering)

When npplicd 10 old.T g"J'-fircd am! oil-fired ulility ond indus"i"l boiler.', WalCr .nd/or ,tc;lm injection

adds m(l;"ILlr~ i"lo Ihc low.T furn;lcc, GOnClIlTent wilh or near (10 lhe .,ide orshghlly ab<>,'c) lhe burner"

supplieJ from Ihe boiler'" trealed feedwaler 01' am"liary slea", sy"lcm" via" mcl<Ting- pllmp or valve.

"lbeIe has hee" sornc li",ilC,llc,ling "f waler injcelion for NO" emLssions collIrol on ""lural ga,-fired and

coal·fired cyclone h"l1cn;~'. I'or ""ul-{i[(·J cyeJones, Ihis technique is mosl elTecli\'e On hoilcrs bllming

hil"",in(lus co"l; howcver, il has nor been pemlanenlly inslalled and co[\linuouoly "pcr"ted in "'ell

appILcaILon.,. Suocessfull(>ng-term 0l,erot;on llf wmCr in]celion would be difficull for IlgnJte-lircd

cyclone hoiler:s, due to the high moi,ture Icvcls in lhe coal and Ihe need 10 Ieadily ignile ,"d s"'lain slable

eOlnhu<lio" a"d mohcn slag fonnaiion III Ihe eyclone fiunaee". For lhese reason" waler/sIC"", injection.

is conSIdEred lechmcally infeasible for NO" conlrol application al Millon 1<. Young ~IJlion.

BUlII' & McDonnell A 1_(, Mumkula Power Cool"'Ialivc, Inc
APPENDIX Al

Techmcal Fca'ihHil)' As,",,,mcnl Dclail' for NOx Control Technologic.,

A.1.2.7 Fuel Reburn

NOx BACf Analysi, Study

Anolher comhustion ledmology lhat may be applicable 10 conlrol NOx emission" from the Milton R.

Young Stalion unils is lilel rebum_ In a similar mUnner lhat OVerfire air diverts n portion ofthe

combuolion air inpul 10 Ihc main firing 71>ne, lhe rebuming proccss iLwnlves snpplying a portion of lhc

fuel heal inpul 10 lhe boiler al a highLT elevation in lhe furnace_ 'Ibis crcales ~n upper furnace atmosphere

where the rebum fuel's combUSlion produot. causes somc of Ihe NOx fnrmed in thc main burner

cOmbuSlion ~nne and reburn zonC 10 bc convened into molecularnilrogcn. Depending on the amount of

reburn fuel uddcd and the amounl of oxygcn aV;lilable in ille furnace gascs 10 combine wllh the reburn

fuel inlroduced. addilionul combustinn air may be supplie<l uS supplemental nl overfire air. Downslrcam

of Ihe air injeclion e1evalion, the inlenlion is to complele the reaction of any remaining carbon monoxide

(CO) 10 earbnn dioxide (Co,), plus reduce lhe amount ofeombuslible mnller remaining in lhe entrained

flym;h.

The most commOn fOrms ofrehum lechnology applied to utility powerpbnt boilers nre:

·~6'· -. - -PiiN'eri:iooor-rilici'oi'iiztd coo:rrehuh'-(1)Clt"or MiCR);-~n;j - -- --..-- -. ---------------

• Gas rcbum (GR)_

Pul vcrized coal reburnin~ and microni?.ed cnal reburning havc been applied to pulverized coal and

-cyclone-fired boilers_ NO" reducti,," cffiniCllnies of50 10 60 pelnenl have been demonstraled on ea,lern

biluminous coal and mldwestern bituminous and Powder River BJSin (pRB) western subbituminous coal.

while supplying up 10 approximately 20-30% ofthe boiler's Lolal fuel heal inpullo the reburn ?one7,,_

For ulility powerplanl boikT applieaLions, natural gas has been utilized as rehum fuel most onen,

demonstrated in two basic approacbes;

• C.onvenlional ~us reburn (CGR); and

• Fuel_lean gas rebum (FLGRT"')_

Eilhcr natural gas or pulverized coal (lignile) can be used as lhe rehum fuel. A sufficient quanlily of

natural gas is nOl eurrenlly availablc al lhe Millon R_ Young Sl:llion planl sileo Supplying enough natural

gas Lo provide 6 10 25% ofLl'e toial heal input lO cilher Or bOlh boilers al MRY Station is expeeled 10 bc

lc-cbnicuTly feasihle, although transport pipeline inslallalion capilal coslS, ami eurrenl and predicled unit

nmural gas eos!s and operaling economics, are likely 10 he unfavorable_

Minnkola Power Coopenllive, lnc_ !lurn' & McDonodl
NOx IJAlT Aoolysls Sludy APPENDIX A]

Tcchmc"l Fc.,ihili'Y Assessrnenll>tlaib for NUx Control Technologle,

--------

VarlO"'; forms offuel I ehumlng hnvc Ixen Je1l1onstraled and operaled roullnely on cyclone boilers for

NOx emission conLrols_ This has been applied 10 unjl.S Jiring c~slem bituminous coal, and we3lern

.,ubhiwminous or I'RIJ/biluminous eo<1I blendR, using pulverizeu or micronized eo"l or nalural gas as Ihe

1I10s1 COlnnLOO rcbllm fucL ReblU "ing lilr NOx cmisoions reductJon has nnl been deTnOIl~lrJ l(oJ on a unit

filing high moislure, low ileal conlon1 North Dakola Ilgnile_ Pulv~riz~d/m,~roniz,,<l co"l, "long Wilh

conventJon"1 an,l fuel Jeau g", reburn ted",ologie~, "f{' dlscussed below_

A.1.2.7.1 Coal Reburn

10 Lhe cusc of applYlllg cooveoliollal e();JI rcburn 10 cyclone boiler., the exisling ~l"'lones ore Sll pplied

wllh the majority ot-rhe Iud, with <,Iher nalural gas or I'ulveri~c~l co"l (ligllile) used as Ihe rehum r,,,:]

,uch Ihat the 100al heaL I"pullo lhe boiler is eRsenlially the same uS wilhoul fuel rebum_ Separalod OFA

ports are localed abllvc lhc rcb1l1l1 fuel injection secl,on or Ihe f,<mace. TheRe SOl'A POri, pruvidc

.mflicienL oxygen in a convenlional fuel rehum ill"l"llHlion 10 complele Lhe cornbmlion procc" thai

begi", in Lhe m"in combustion zOl\e 011<1 i, ,upplcmclllcd in the ",burn and b,rn](}ul zones. This is shown

,chemalically for a pulverized CO"1rcburn applicalion 01\ "cyolone--fir<.,j boiler wilh SOl'A In Figure A.IL

Fil::ure A.l-l J'uh-erizcd Coni Rellllrn Appli~"lion on C~'ololle Boiler Wilh Ovtrfirc Air'

- "

--\

\

BOILEll

""""-T , BURNOUT i.. lONE ELECTROSTATIC

, cc

PRECIPITATOR I ( "

F" - C REBUR~ ( AIR E~ ZONE V PREI1EATER L " -

J . S~C<lNDAR}---/ COAL STAG -

- - VVV '" -

lJj '---'

--- . . - :_;:::, • PRIMARY

". AI" '-'- ' {'

- - - -----, - - - -~~·~~~~~f -

,;J

CYCLONE

BURNF.R

DRY WASTE TO DISPOSAL

_~JQLTEN SlAG

~'" COMBUSTJON

ZONE

WATER ---

OVF1FIRE

COAt

""

REBURt"'N

BURNE;R$

'"

PULVERIZED

COAL

SLAG TO DISPOSAL

Burm &. McDonnell A 1-8 Minnkolo Power Coopcr"livc, Inc.
APPENDIX AI

Technical Fc""ibil;ty AssessmeJlt Delll;J, [or NOK Conlrol Technologie,

NOK BACf Analysi, Smdy

ltllhe Uniled Siales, pulverized coal rcbuming and micronized coal rebuming techniques for ulilily

powerpbnl NOx emissions re<luclion have been applied on a very limilcd full-sca]e, full-Lime basis 10

cyclone-fired boilcTIl in field demonstralion le,ls and longer-Ierm demonstralion opcntlion, respeclively.

There h"ve been only two known pulve,i.fi'{i or micronized coal rebum msTallations in !he Unilccl SlalcS

on cyclone boilers, one On a uLility boiler in Wisl."(lnsin, and one On a small industri"l_sizc cyclone boiler

in Ncw York sLale"'·"''''''·''·''·''. NOx emi,sions reduclion efficiencics of 57 percent h"vc bCI."Tl

demons 1mled on CYclone boilers firing "asLem hituminous coal. or midwcslcrn biruminous and Pow<ler

River Basin (pRB) western &ubbituminous coals while supplying up 10 approximalely 20-30% ofihe

boiler'& total fuel heal inpuL to lhe rebum zone. Wilh Ihe exception of the U.S. Departmenl of Energy's

(DOE) Clean Coal Tc"Chnology Program demonstration projecls""', nO known cOinmerc,ally-avC11able

coal rebum syslems have been inslllllcd and are roulinely opernled on cyclone boilers in the Unilccl States

10 date. The DOE-COP projects foccoal rcbum applied 10 cyclone boilers are dc>cribed below.

···..P!,lveri"ed. coal rebuming for NOx emissions recluclion-'n a.cyclone-fired boiler!Nlls dc;nonslraled on lhe

110 MW Nelson Dewey Unit 2 for Wiscoosin Power & l.ighl in 1991-1992. Reburn fuel prepHm\ion and

handling, rcbum burners wilh fluc gas recirculalion, oncl a -Se[llilllled overfirc air system were addecl. Coal

reb.urn lesls were eondncred on this lIJlil while firing biluminous and PRll coals. NO" emis.sion control

dlieieJ\cie.' of 50 to 60 pCTel.lll, with reduclions from 0.75--0.83 Ib/rnmBllI haselines 10 around 0.)8

IblmmBtu, bul as low as 0.29 lO 0.32 IblonmBtu, with PRE coal al full load wilh approximately 25-30%

of the lotal fuel heat inpul from rcbum fuel were demonstraled.9,11,1I The rcbum syslem is no longer

operaled on Nelson Dewey Unil2.

Micronized coal reburning has been demonstrale<! in 1997-1998, and continues to operale year-round on a

sJII:lH indu'lrial cyclone boiler (400,000 lblhr sleam outpul, 50 MW gross equivak"Ill) lor Easlman Kodak

Compauy at thcir Kodak Park raeility in Roche&ter, NY. Thi, unit (Boiler #15) achieves a NOx reduclion

eflicil."Tley or approximalely 57 percent on eastern bitumitlons coal, involving limited oyelonc air-staging

(cyclones believed 10 be ,lighlly above 0% exce.,s air) and a modesT amounl ofov"rlirc air injeelion

clownsirearn oJ!hc micronized reburn fuel input nozzles. ApPrOximately 17% oflhe boiler's 10lal ruel

heal input is tyl'icaHy supplied 10 the reburn zone. This coal 'ehurn syslem conlinues to operate roulinely

althis facilily. This inslallDtion i& reported \0 use a Fuller MicroMill 10 produce micronized coal wilh

80% passing Ihrough a 325 mesh screen'···u.

Mionkota Po""" Cooperalive, Inc, AI-9 Borns & McDonnell
NOx HACr ATIolysi' Study APPENDIX AI

TeclmicoI Foasibilily A"c",mcnl Dolail., ror NOx ConTIol T""hnolegio'

]fa coal rcbum ,yslcm w"s uppli"d 10 MRY Sla~on boilers, Ihc cxi"ling; cyclones would be .,upplied w,lh

Ihc majorily oflhe fuel in Ihe Conn ofcm,hed coal, and the halance offuel would be supplied 10 a pair of

,lcd,c"lcd pulverizcr>; 10 fl'Cd Ihe rehurn injectioLl p0l1" such thallhe lolal beat inpnl10 Ihe boiJcT is

essenlially Ihe .'arne a, WiIboul fud r"bum. In a convcnllOn"1 fud rebum insl"ll"I,on, UFA port' locale,]

abo~c Ihc rcbum ""clion of Ihe furnace prov,de ,ufficiem oxyge" 10 complele Ihe C(lTnbmlion proo"" thai

hegin., in Ihe main cornlm,tion ZOnC oml '" "Jpplemcnlod in the rebum und bumoul zones.

Similar 10 Ihe "pplie"lion of,ep"mled ove, Ilre air, ~lere are polential impacl, and lim;IUlion" unique 10

Ihe liring of NOlth Dakota jignile in cyclone_fired hoikn; u,al ,hould be rt:eOb'J1izcd as pari of Ihis

emi"ion reduebon teehnology applicalion. A"" rcbllm f"d, hgnil~ i~ expecled 10 behave approprial<:ly

upon inlroduclion in the lower middle furn"cc 10 help reduo~ NOx emissions. TI,e concern, are ihallhe

diversion of" sib'J11lie"nl amount of heat inpullrom Ihe cyclone barrels 10 u,e as a WlIree ofrebllrn fuel in

the fonn ofpulverized or micronized lignile may reduce eyclone lemperalures C"Ilough 10 inhibil sJag

Iormalion and now, e,pecially a, boilcr lo.d i, reduced. AJr·Slaging lhe eycJones with Ihe use of

,ep"raled owrfire air 10 furlher tOmpk"Illtnt combustion NOx rcduclion as part orthi, rehum l.<:dlT\"lLl~

will furlhcr nsk sl"g; ·'frc"{·zmg" in Ihe barrels and lower lu",ace. Redtlcll1g lhe number or- aelivc cydones

whIch are air- and fuel-slaged to accommodale redu~ed firing rare, while opcrdling a co"I-Jired boiler

Wilh rebum and ,eparaled ove, IJre air is lh~ Iyp;~al "ppro"~h to avoa] sbg I"pping problems.

]'olenlwl NO" cmi",wm rcducllOn performance lS expecled 10 be limiled 011 lignilc-fired cyclone boilers

with a basic fonn ofsepamled overlire air sys(~m, <in~e lhe rehum fuel mjeclion localion is expected lo

coincJde with the eXlS(ing liguile pre-dryin;: "y'lcm venl purlS. The arno,mt of oxygen introduced by tl'e

,'enl perl\ will be rlioruplivc 10 'my convenlional rebum process ill Ihal it would require mueh highc"]"

rcburn rucl inje~lion r"t~s lO "n:ate a subsloichlOmetric atmosphere in Ihe lower sc~ofi,bry furnace that is

conJueivc to promoling in-furnace NO" reduclion_

SigniIiCOfil addilions lO the fuel prt:p"nrlion equipment ill the cxisling plam faeililies will he rcquired.

The cool rt:bum sySlem expc'CI"dlo bc "pplied to MRY Sialion boilers may use Iwo new finc-b'lind

pulverize" and dynamic cla"-" lier< 10 aehi"vc Ih~ level ofCo" I particle size dish-ibulion required.

11igher unb"mc"{l ~,,,bon levels in the ilyash exhamled Irom Ihe boiler may occur, espeoially when Ihe

rdmrrt fuel i, coal, and Ihe regular burners art: fired with Jess Ih,rn Iheort:lieal amouIlL, or comb"Slion air

comrrtonly pmcliced with the u,e of overflrc alL Lowering, Ihe reburn fuel injeolion cleva lion, JC'Cfeasing

Burn> & McDonnoII AI-IO Murnkela Puw~r Conpo""i,'", Tne,
APPENDlXAI

Technioal Fea,ibility Asses,ment Dolail, for NOx CcOlrol Technologic.,;

NOx BACf Aoolysis Study

!he amount ofreburn fuel, and grinding: lhe rebum coal 10 a greater degree of fineness can hclp 10 offset

sume ofthe increase in Ilyash unburned carbon conlc'TI!. Rue gas opacily from the slack may inorease if

the panieu]ale removal equipmcnl is an elcclro,llIlie precipitalor, due primarily to reduced resislivity and

,mailer partiele sizes of the Ilyash.

An issue that ulTeclS the fea"bi~ly oflignite reburning is 1he uplime required fur the lignile rdum fuel

pulverizing systcm, and impaci oflhe rebllnl sySlem on effccliveness in reducing NOx emissions during:

load changes and lower loads. Typicully, one new pulverizer is dediculcd 10 prqmrc rebllffi fuel in

exi"ling pulvcri7,.ed fuel-fired boiler upplicalions. Cyelones may be fired with less fuel or deactivated

during boiler o""ralion in order to accommodale ohanges In fuel combustion characteristics, boiler load,

and for schcduled or unsoheduled individnal crushermuintcnance. Milton R. Young Station Umt l ha.,

scvcn crushers for cyelonc coul grinding, cach dedicaled to one oflhc seven cyclone furnaces. Diverting

as much as 30% of the total heal input as reburn fuel could require lwo oflhe exisling cyclones 10 be

deactivated, and two new MI'S-89 pulverizera to bc dcdicated to rebum fuel preparation. As each of

. Ihesemills requires periodic·maintcnance"boiler emissions and/or.load cnuld be negatively.impaoled

during'individual rebum mill outage periods while the boiler remained in sCTviec. A high level of

fineness of coal p.rtieles from (he rebum mills is important (0 achieve and maintain in ordcT to limit

incn::ase, in flyash combustibles. A minimum of60 percenl passing through 200 mesh fineness is

recommcnd~..:lby One of the reburn technalogyvendors (B&W) for pulverized lignite rebum. Mieroni7.ed

coal reburn requires even greater finene.,,: 70"80 percent passing Ihrough a 325 mesh screen.

Pulverized or micronized coal reburn with Ihe advanccu form ofseparaled overllre air (ASOFA) oan be

applied and inslalled on MRY Silliion Unit I's boiler. These combined lechniques arc expeoled (0 reduce

NO, emissions npproximalcly 5~% from current pre--conlrol buscline levels (down 10 0.385Ib/mmBtu)

for Ihc MRY Sialion Unil I boiler. These levels ofNOx reduction depend on the advanocd form of

separ.lcd overfire air lechnique 10 achieve the expected NOx reduclion percenlages when applied 10

lignile-fired eyclonc boilers, which may nol he successful given the conCernS expressed aboullhe • pOlcnlial impacts of Ihis lechnique. Uaing finely pulverized lignile for reburn fuel is considered

lechnioally fcasible for NOx emissions control under ev.lu"lion for applicalion 10 MRY Stalion Unill 's

hoiIeL

MCnnkol' Power Ccopornli"". Inc. AI _11 Bums & MoDonnell
NOx BACT Anoly,is Sn1dy Al'PENDIXAI

Technical FcosibiJily A>se»m<I11 Dtlall, r<lT NOx Control Tcdmologie3

A.1.2.7.2 Conventional Gas Reburn

Nal"ral g~s hn, been prcfCITC,1 as the rehurn fuel (If ch(lice. Naruml ga, h•., bec-n <Jlilizcd forrcbum fuel

In [I\'O ha.,i~ apl',ooche" o(l"wnlion"l reblll n and fuel-lean gas relmm. In lhe conwnlium,l "pproach, up

lu 30% oflhc bollcr'" lolal fuel heat inpul '" "upplic~ 10 lhr rch"m zone, followc~ by a ,ignificant 'muunl

of overlire air for complelion orcomhllSlion plior 10 flue gases exitmg lhe hOlier.

Conventional gas reburning in a cyel(lnc-fired boiler has been available al Tenne'5ee Vnlky A" Ihurily's

Aile" Sialion llnileL' #1 (JOO MW) ~inc. 1998. The reburn lechnology provider (ven~or) claims NOx

emissions WeT" ITduccd 67% from" full-Ioa,1 b;"eline of 1.29 (down 1(> 0.42) Ib/mmlltu when tiring;!

blend ofweslern biluminous and PRB eu"I,", Conve"Dlional g"' rebum fuel input rales were rlOI

available jrom lhe ledmology vendor's lilc,"lure. Anolher reference source of informolion sliLled NOx

em;f;.,ion' were reduced 65% Ii-om a f"U-lo"d baseline of 0.86 (down to O.JO) Ill/mmBlu wilh 7 percenl of

d,e 101,,1 fuel henl inpUI.'[jppli~<1;," rcbum fuel'.

A schemalicgmphicofconvenlionalgasrebllmon;lp.. lv~riz("(1 coal-fire,1 boiler;" "hoWTl in fiRIlre A.I-

,

Figure A.I-2 N~tnr~1 G~s Rebllrll Applic~tion nn

Wnll-Fired Pulveri7,cd Coallloilcr willi Onrlire Air~

Bc>LER

<.

ECoNOMJZER

OVERFlREAIR

NAlUR~L GAS

RECIRClJlATfD

HUE GAS

WNOIl°>:

c~,

""

LOW-NO,

BURNERS

• •

- R~RURN

, ZON~

• • .

'"'}

"""T'T';;;~

~I.LL~ " W""":'-~""'''''.'

TO OISf'OSA,

BIIm., & ~cDuItndl Minnko," Po,",,,, CoopeT.Jlivc, Inc.
APPENDIX AI

Tcchnioal Fcasibilil}' Assessment Detail., for NOx Control Toehnologies

NOxBACT Analysis Smdy

Similar 10 !he applicalion ofseparaled ovcrfire air, there are polemial impacts and limilations unique 10

Ihe firing ofNorlh D",kola lignile in cyclone-fired boiler>; Ihal should be rectJgniZ<...:J as part of Ihis

emission reducllon technology applicalion_ l'or Ihe moSl cJTeclive NO" Teduction by npplying Ihe various

available fonns offuel rebum, lhe injeclion offuel is usually pLTformed using recirculaled flue gas as a

,hlu~"t al\d carrier media lo "id dispm;ion and avoid completely oxidizing Ihe oarbon nnd nilrogcn

componenls in lhe fu~1and furnace gases from "taged burnersfcyclones_ Illl'roved gas reburn d~signs

have r~duced or elimillilled FGR wilh higher gus injection pressures. For lignile-fired cyclone boilers,

rebum fuel firing with a basic form ofseparaled OVLTfirc air is exreolod 10 be much less cffcclive in

reducing NOx emission:; than previously demon:;lraled ds~whcrc. This is related to the likelihood Ihal

!he injection ofreburn foci will he near Ihe elevation oflhe existing lignile drying sy&lem vent ports, and

!hal lhe oxygen inlroduced w;lh Ihe lignite drying &ystem's venled moisture win disrupl the d~.,ir~d infurnuce nitrogen oxides reduolion process.

11 should bc recognized Ihat application of air-staged cyclones wilh hasic or advanced forms of SOFA

'<c.,. with rebllrn leehniques will require th~ overfire air injection ports to bc.Joca1ed at a somewhat lower

clcvalion of!he furnaoe compuTcd wilh uir-slageu cyolon~s wilhoul reburning. TIus mCanS Ihat less airslaging ofthe cyclones may be pmc~oed.or thai less resjd~nce lime will be ~vailahle for Ihe in-furnace

..NOx reuuetion process 10 OCCUL

Similar 10 coal rcburning, lhere are COneernS !hal wilhholdlOg a significanl amount ofhcal inplll from the

eycl"ne barrels to Use nuturnl gas a, a source ofreburn fuel may reduce cyclono ll'Illpernlurcs enough to

inhibil slag formation and Ilow, especially as boiler load is reduec-d. Air-staging Ihe cyclones for use of

separaled ovcrfirc air 10 funh~r compl~menl combu'lion NOx reduction as part oflhis reburn leclmique

wi]] further risk slug: "frcC',,;ng" in Ihe barrels nnd low~r firrnace_ Reuucing the numbcr of activc cyclones

which "TC air· and fuel-staged 10 accommodale reduoeu firing rale.1 while op=ling a coal-fired boiler

wilh conventional relmrn and separated overfire air syslems is !he typical approach 10 avoid slag lapping

problems. Natural ga,rebum wjlh Ihe ndvanccd form of&eparaled ovcrfire air (ASOFA) Can be applied

and inslallcd on Millon R. Young Sialion's Unit 1 boiler.

Although the unit opcmting and c"pilul cools 1<> supply large qnantilies ofgaseous fuel not currenlly

available allhis sil~ are economic di."dvantages, using high-pressuTC natural gas for rebom fuel i,

considered rechnioally feasible for NOx emissions control under evalualion for application 10 MRY

SLaI;on Unil l's boiler.

Minnkola Power COOr."liive. lno. At_13 Bu",s & McDonnell
NUx BACT A~"lysis Srudy APPENDIX AI

Teohnic"l F"",ihiliry A...,""mcnl Dcl"l, for NUx C'.ontml Technologic.,

A.1.2.7.J Fuel Lean Gas Reburn

ALlolher approach 10 Pi'S "ebur"iog is "flld-IcHn gas rebum" (FLGR"") lechnology, which injcclslimllc<l

amounls of nalural gas (opproximalely J-I 0 perce", of Ihe tolal fuel he"l mpul) "hove lhe humer., (or

cyclone.,) wilh 01' without .,igni ncant oir-sl~eing of Ihc b"m~n; (cyclones) or lhe add ilion ofovcrfire air

up~lream of lh~ fuelmj"clion dcvalion. FLGR'R Ijest neld-leRI on 0 cyc!om'-fired boiler wa" at

ComillonwealLh Edl,on'" Joliet Uni t (, (J27 MW), " 9_cy~IOl"".furnace bOiler" _ NOx emi",;ion, reduclion

with I'I.GR (wilhoul SOl'A) was believed 10 he approxim;llc1y 35.-10% wllh 7% of Ihe boiler', 10~"l1 fuel

hcat inpul suppli~cl in Ihe rcbum zone. This test yielded O_5~ Ib/mmBlu NOx emission, jj-om a ha,eline

of O_~810_ One other cyclonc hoiler has been modeled using computational fluid dynamic> (CFD) '" p"rl

ofa sludy looking at applying FLGR at Owensboro Municipal !JrililieR' Elmer Smilh Slalion Uml 1 (150

MW .,illgle-wan, ea,tern bituminous coal_lired bOller). Thi,; morlel predicled tharNOx emissIOns coulcl

be reduced by 25·30% Olver thai aohiev.ble from ove-rfirc "ir and SNCR "_

More commonly. FLGR'" h"s bce." applied 011 medium lo large pulvcrizccl co"1 wall-fired hoilero

hurning ea.,rern hltuminous orwe,lem suhbiluminous eo"]<;_ On Wioconsin Electrjo PoweTCompany',

(WEPCO',) PJcn,'ml Prairie Unil I, a 620 MWg Riley lurho-r,,,,cl wOl·bollom (slagging) boiler, FLGRTM

alonc was prcclictcdlo r",luce NOx ,missious by J5-]9 rercenl at a !l'LS rcbLlm lale of7-8 I,e,cent hul only

achieved 20% tl-om a baselinc of0.45 Ib/mmElu"-"_ Tllis lS pre,umably wllhou[ burne" "ir-sl:lgm£ or

SOFA. II has also boen applied in combimllion ",ilh SNCR allh" WEPCO silO.

A poll'llli"1 adv,mlago of!'l.GRTM over convenlional gaR rehum is th"1 the furme, is generally comralLble

wllh, lml does not require, lhc instalblion and opemlio" of.sOFA_ The slaged reburn ruol i~ inlmducorl

inlo an oxygen-rich almo,pherc dO'Vllsh-eam 0 f Ihe humers and any OFA injeclion poinl~. Thc "mmllli of

"olmm ruel jnJecled is typically limiled hy acccpl"hJc carbon monox ide levels in lhe boiler exil nIle gas.

There are poten~al impacls and limilaliom unique lOlhe firing orNorth Dakota lignM in cyclone-fired

hoilm lilal should he recognized as part oflhi:; emissiun reduolion technology applie<'lion. This is

.<ignificanl, c'"pccially for aliem~live, wilh FLGRT.. technology when cumbined wilh hasie Or Hd\'HnOccl

.sOFA 10 aHow lhe nalural g"s introcluced ahove Ihe SOFA port" In bum completely prior 10 Ihe furnace

c~il plone_ In eilher case, lhe amounl of addilional pOlenlial NOx reduclJOn I'",sible with FLURI>t is

limilcd_ sincc the rehum lilel injeclion lo,alion is expected 10 coincide wilh Ihc exisling lignile prc.,lrying

"yslem vcnl porto. The arnounl of oxygcn introduced by the venl port, will be di=pllVC 10 Ihc fud-lean

Ilum, & McDon"ell AJ_l4 Minnko," Power COop~,"live, lnc_
APPENDIX AI

Teelmi"al F,.,ihility AssessmeJlt notail' for NOx Conlrol Technologios

NO>< BACT Anal"..;, Study

reburn proeess in that it would require much higher relurn fuel inJeolion rates in Lhe lower secondary

furnace to promote in-furnace NOx reduction. There are reduced concerns thatth. wilhholding of~

modest amount ofheal input from the cyclone barrels to usc natural gas"s" source ofreburn fuel may

reduce cyclooe lemper"lurcs enough 10 inhibil slog formation and flow, especially as boiler load is

reduced. Air-staging the cycloncs with the nse ofsep"raled overfire air 10 further complement

combustion NOx reduclion is an oplional part of lhi, reburn technique which will f"rthcr ri,k slag

·'freczing" in lhe harrel, and lower furnace.

Fuel lean g"S reburn can be applied and installed On MRY Slalion Unil I·s boilcrwilh or without

SOFNASOFA. This lechnique is considered lcclmica.lly feasible for appllcalion 10 MRY Slalion Unil I's

boilcr_ Expected No", reduction will be modesl for FLGRTM without SOFA and FLGll"" with" basic

form of SOFA. Unil opemting and capilal cosl, to supply large quantitie, ofllaseons fuel ~ot currently

available .1 lhis site are economic disudvanLageo. "Because ofthe,e fscton;. lhesc varistions ofthis

technology will nOt be cost-effective compared lO olher allern.lives wilh simibr OOntrol effeclivcne's.

".- -FLGR~" witho-ul SOFA and-FLGR"" with a basic form ofSOFA wcn:'not'included-in-lhe-conlrol

',... effectiv~"ilcssand cosl-effecliveness seclions of lhe main fl.."porL

.Olhcr demonstr"lcd forms of fuelle"n gas rcburning in comhination wilh po>t-combuslion lec1mologies,

.such a, amine-enhanced fuellc"n ga' 'eburn (FLORI>< wilh SNCR). are di,cusse<! under lhe layered

lechnologics seclion_

A.1.2.7.4 Fuel Oil Reburn

Fuel oil h"s ken SUbsliluled for naruml gas in a convenlional reburn applicalion. This is much 1c"

cOmmon in the UniK-d Stale, lhan u,ingnalural gas as a reburn fuel, due to lhe genemllack ofdem"nd

"nd difficulLie' in supplying lhe volume offuel oil which would be required. II ha' been insLalled

commereially on three 350 MW oil-lired boilers in New Brunswick (Canada) allhe Colcwn Covc plant

NOx emission' reduclion with reburn and SOFA was 7~% with 25% of the boiler's lotal fuel heal inpul

supplied in the reburn zone. This yielded [}_22 n;/rnmBlu NOx emis-,ion' from baselinc of1.0

Ib/mmBru'. No cxamples of conv~"illional fuel oil reburn applied 10 a coal_lired cyclone boiler were

found in av"ilable likralure.

Fuel oil reburn could pOlcnlially bc consid~'rCd for application to MRY S~lion Unit I and Unil2 boilers_

Invesligalion of the specific source, dislancc, and costs for ,upplying si6'11ificnnlly increased quanlities of

fuel oil vin lransport trucks hauling lanker trailers or underground pipeline 10 M.R_ Young slnlion has nOl

Minnkola POw<'1" Cooperative, lno_ AI-15 Doms & McDonnell
NOx BACT Analy,is Study APPENDIX A]

Technioal Feasibilily A""ssm~nt Del"il, for NUx ConTrol Technologies

been p<-Tfomled. The umt operaliLlg oml capital co,ts lo sllpply large quanliIies ot"high-volume liquid

ro"il fuel al tl", silc me economic disadvanlage,. The concern,; r~ganling polenli"l imracls ;md

hmilatlon, uniqlJe 10 the firing ofNorth Dakola lignile in cydo,",,-lircd boiler>; lhal "hould be nxogni'"d

a, pan of lhis emission rL~lue(jon lechnology "pplicolion UTe Slmilor lo lllo,e expre"eu for conv~nlional

I:ns reburn_ H i, hch~ved lhal 1'01~llliul NOx conlrol wilh oil t~bum would hc slighlly less Ihan

comparable convemional AUs [{·bum 'y,I'--n18.

Although fuel OJI rebllm could pOlentially be coosi,bed for apillioalion to MRY Sialion Unit 1's boiler,

lhe lack or any di"linct pOleul;.1 NOx redUCli\m .dvantages "n,l demonslral,on on cyclone-frred llOilers

doe., 1101 "pp~ar 10 sUIlPOrl ii, eonsideralion, 1'h1, aJlemnlive w"s nol included io lhc NOx conlrol and

cosl-effccliveness analysis.

A.1.3 Posl-Combustion Controls

Post-combuslion cOlllrols dcal wilh Iechlllqlles lhatlhcmmlly or chem;c"Jly_lrenI Ihe Due ga.,es 10 reduce

NOx emissions .ner lhey have exited Ihe boile,'s lower fUnlace_ III Ihe C",~ ofMIllon R. Yo"n~ Station

Unil I, lhi, t'nmurily involve.' forms of ""leclJ"" calal}1JC r"lhJclion (SCR) anu ,eleCI;W non--caUilYlic

teducliQn (SCR) lechnologics. Another emergmg lechnolol,'Y that has recenlly eLllored Ihe comm"rcia]

markcl is Powe"'l'ao's Eleclro CailllytlC OxidaIJort', WhlCh treal' nlility ll(11!cr nIl" gas fo,· removal 01'

nilrogen oxide.', ",lfll[ oxide" and mercury. Another emerg;TIR lCchnolo;,')' Ihal has recen(]y enler"ll Ihe

com",~rei~1 ulillly air pfJJlution contrQI morkd is Powerop"n'" JOleetro Calalytic lliJdation"'. which lreals

holler nllc ),'<," for removal ornitrogen oxirl~" sulfur oxides, anu mercury.

A.1.3.1 Selective Non-Catalytic Reduction (SNCR)

Sel~Cliv~ Non-Catalylic Rnl)lclion (SNCRj, and val'lalions such as hydrocarhorHnh,mccd SNCR (sold

under Ihe Irade name ofNOxSlar'fM), nnd Rieh Reagenl Injeclion (RRl), aIT "II posl-comhnstion lype., o[

bfJiler NOx ~mi"ion commk Whde lhe,e tcchnologies ar~ in,cn"live 10 the specific flld type, whose

COmbUSlion proullcl' are being lrealed. lile largo l)lajority of boil er "pplicaliom 10 dalC have been On

pulverized coal-fired unilS burning eamen' hituminous ["ds. SNCIl has httn tlS",llo reduce NOx

el11;."ioll.' 011 numerous u~llty hoilers burning ea,lern bituminous coal, midweslern biruminous cool, "nd.

to a lesser exlenl, westem suhhirum;nolls ooaL SNCIl hos also been used wilh fuel oil and natural g"'-

r",,-d llnil,. SN ell (and hydroe.rbon--enhaoe",l :'>NCR) l"Chnologies can e.ch he applied [0 cyc!<lne

boile" Wilh or wi'holll lhe u,e ofa SOFA 'ystem, SNCR docs nol "ppcarto be del'''wknl directly on the

'Yl'e ofburners (wall-fired, langenlinlly-fired, and cyclol\e_r,rcd) employed in the !mllers whe", il has

Bum, & Md)unndl A 1-16 Minnkulo Power Cuopcrotive, Ino.
APl'ENDIX Al

Toehnieall'easihilily Asses,mOI" Detail, roc NOx Control T<ehnolog,",

NOx BACf Analysis Sludy

,'

heen installed, with or without overfire air in full opcnttion. Opcrallon Ul th"", plants has demonstrated

thal SNCR can decrense NOx emissions as much as 15-40% at full load, mo,l typically bctween 25_35

percent".

In the conventional SNCR process, urea or ammonia i~ injected into lb.e boiler in a rcgion where the

combustion ga' tempe",ture is in the 1700 to 2100 degrees F range. Under these lemperature condilion"

the urea reagent lCO{NH,), J or ummonia LNH,] reae!$ wilh Iho NOx, forming N, and water, reducing

NOx emissions.

Long·tctm examples where SNCR has been 'Ised to reduce NOx emis~ion, on two oyclone-fired boilcrs

are on a 13& MW uni' and 160 MW unit burning ea,tern bituminous coal al Cone'Ctiv's B.L Englaml

Slalion (Units 1 and 2) ,inee 1995 and 19%, respectively. Tests u( these planls demonstrated that SNCR

can decrease NOx emission~ as mueh a~ 30-36% at full load, rrom uround 1.3-L4 IbfmmBlu respectively

to uS low as O.gS IbfmmBtu (without ove-rfire air)"'''''". These hoHen, located nea, AtlantiC Ci Iy, New

.Jersey, con-l,i,u'e Loopei':ite SNCK(with-Of"A) roi""Jlili,ual'NOx'CmLs,ions- around 0.55 and OA5'lb/rnmBlu,

. '. 'respeotively.

SNCR oan be 3pplied and inslalled on MRY Station boilers. EslirnulCd NOx emis.'ion rnlCS for osirt&

. SNCR wilh North Dakola lignite considered published levels achieved by cyclone-fired units firiTIg

weslem suhbilnminOll' coal, and vendor prediclions. SNCR alone is expoeted to reduce NOx emission~

"pproximJlcly 37% from MCR bJseline levels (downlo around 0.5lh/mmBlll) for lhe MRY Slalion Unil

I boikr wilh ammonia slip limi[Cd 10 appro~irnately 5 ppmvd. Becall,e or lhe opc,-ating costs of lhe

consumed reagenl, lhis lechnology w,ll not be LOsl--effeclive cOTnllaroo \0 Olher allcmalives with similar

control elTcclivene~g (i.e. SOFA), SNCR alone wus not included in the control elTecliveness and costelTccliveness sections of the main repon.

Other dcrnon.'lntc<! form' ofSNCR-reIJled lcelmologies, such as Rich R""genl Injection wilh SNCR, and

"mine--enhJnced fuellcan gas reburn (FLGRTM with SNCR), are discussed under Ihe layered technologies

seclion.

A.1.3.2 Hydrocarbon-enharu:;ed SNCR (NOxStarTII )

HydmcJrbon--enhanced SNCR lechnology, commercially markeled as NOxSlurTM, is offered by a single

vmdor (Mil,ui Baboock) as a poSH:ombuSlion type ofenhunred SNCR lechnology, whereby an

Minnkol' Pow.:r Coop<ralivo, Inc. At ·17 Dums & MoD<Jnnell
NOx B/ICT AlInly,i.. StlIdy /lPPENDIX/l1

Tednieal Feasibilily /I"e.~,men' De,"ils for NOx CUlIlml Tecllllulogie'

~mmunia-based re"g:cnl is conlinuou,ly injecled inlo lb<: "upc'Th""ler/rehealer pass of an opc'TIIting boiler

wilh small "muunls ofga.,eous hydrocarbon (typienlly either namrnl gos or propane) and air or ,tC<lm 10

provIde Jnn~,- cuuling and aid reagenl di,pel ,ion. The targeled COmhUf;llOrl r.ns ImlplTulure rang" is

hel we<." 1500"r: nnd 2000"1'. The allluuni ufg",COU' hy,Jrocarbon inlrooucnl " 'mall erou(lgh (0. I I"

0.2% OflOLOI f(ld heal input) lhallh" is nol intende<110 "01 as a form ot·rehum Or "Iuged fllel combuslion.

All "'THy of l'ermnTl~nlly-illslalledijJie~lion hmces aI e 10tal~d wllhin Ihe boiler conveclioTl pilS" divided

inlo numer1)", <hserele zone" across Ihe full widlh nn<1 hcighl or Ihe dUCL Th~ hy<lru<:arbon aUlo-igmtes.

forming hy<lroxyl (011) rad,cals which reaCI Wilh the NO, and ammonia 10 produce elemenlal nilrogen

(N,) und waler vapor (A,O).

NOxSlarTM was demon,lmled al Tennessee Valley Authority's Kingston Power Slnlion Unil 9

(taLlgenlially_fired 200 MW lwin-furnace hoiler firing ",,"Iern biluminou, coal) in 2002". Tllis

technology was "uh.,equCT1tly pcrmanen1Jy-inst"lled"1 TVA's Colberl SI"llOn Um14 in late 2003 on a 192

MW wall-fired hoilcr burning easlern billlminous coal". NO" rcdu<:lion wa, ,taled as 68-80% fOl' Ihcsc

"pplicat,oLlS, which included the imp<1el of overJire air and <lir_slaged comhustmn "pstre<lm oflhe

ammonia ~nd propane iLljeclion loealions_

An example of a hydroearbon-enhanct:o<:l SNClt insLallaliOll On" wall-IlTcd pulverized fud boiler is ,huwn

as" secliorlal sid~ c1ev<llion view oflhe (lpper Jumacc in Figure A_I-J.

flm,,, & McDon"dl AI·IS Mi"nkoLa Power Coupera""", Ino.
c -

APPENDIXAJ

Technical Feoslbility A'<essmeJll Delails for NOx Control Technologies

.",...-,--- ----

NOx BACT Analysis Study

NOKSIOTTIt

ammon;alhydrocarbonJ,loam

injeclion lanoe, {venical

lanto, bohiod secondary

superhealer inlel rubes

Figure A.1-3 Hydrocarbon-enhanced SNCR Application on PC-fired Boile,-22

The supplier (Mitsui Babcock) ofhydro=bon-enhanced SNCR technology claims there is liltle

sensitivity lo the type fuel (coal) or burncrs this lechnique can be polentially applJed to in order to reduce

NOx emissions_ The chemical reagent injection for hydroearbon--enhance<l SNCR (NOxSlarTIt) NOx

control technology must be precisely locaLed 8Ild carefully controlled 10 be effective. Operation outside

of thc required operaling muges can even resulL in increased No" emissions. EXlenslvc compUlalional

fluid dynamic (CFD) model simuJlllions are needed to delcrmlne lbe optimum injection poinls and spray

patterns_ Boiler operaling conditions change wilb unilload and varying fuel characteristics. The

NOxSlarTM process con 001 system musl be able to a<!j usl for lbcse changing conditions in order to be

eJTeclive lhroughoulthe inlended load range and firing C<lndilions encountered. Non_relractable ammonia

injcction lances arranged in a parallel-series m\inner are pcimanenlly mounted inside lbe upper furnace

zone, attached 10 conveclive lube elemenls. DiITcrent sections of lhe injcclion "grid" can he turned offor

on, depending on load and firing condilions and amounl ofNOx reduction required. Injection nozzles are

continuously purged and cooled by exlmcted superheated steam from the boiler's main steam outlet,

whelher ammonia reagent is being inlroduced into the flue gas stream or not. Ammonia slip can be

minimized by Injceling less reagent, allbough NOx conlrol performance will be reduced_

Miankola Power Co",ernl;ve, Inc_ AI 19 Bums & McDonnell
NO>: RAC1 Aual,.,i, Srudy APPENDIX AI

Ttthnical FeaslbJlly A,,<ssmenl Detllil< lin NO;< Comrol TeeJmologies

.._--

There are a number of issue, wiih tiriug Norrh Dakola hgnite Ihat make !he applicability of hydrooarbonenhanced SNCR iufeasible compared to previous expericnce m olher ooal-fired p"wel'Pl~nls. These

issue" iuclude:

• Hydrocarbon-enhaneed SNCR (NOxS tar''') lcchnology has nol beGu applied to cyolont boikr,;

(wJIh or wilhoullhc uoe ufa SOFA sy~lem). II ha, b""n only '1'1,licd lo dale On pulvenzed coal.

firetl bOlkrn burning ea31em III tumino,," fuds.

• There i, no sucoessful u<-1llomlr"le,1 full-scale cxperiencc In 00111 inuous SOn'lCG of hydrocarbon"

l"1lhuuee,1 SNCR (NOxSlarTM) leclmology on lllll1s finng high-slagging coals such as we.slem

subbilllmiuous (PIlB) and ligni,e. The heat transfer surfaces in lhe conveclive heal tTnu,fer zone

where the rea.gem mixture lS mjcclcd ~re prone 10 severe fouling fl'Om Hyash con,liluenls

~ummOu in North Dakoia lignite coals. Fly"sh deposit "c~umulalion on lhe oulside of lhe

NOxSlarTM Junees in Milton R. Young Sla1ion Unit 1 boiler'snpper furnace is expected 10 be

significant, potentially occurring within a matler of a few weeks from slartur and nearly

imrO",hle to prevent or remove efJecllvdy dunng hoiler operation_ Sueh bUildup is expected 10

eanse rnaldislribnlJon oflh. NOx reduction chemical reagenT from ihc mjeelion nozzles.

EITe~llV~ ou-hnc removal of lhese deposits from lhe injectiou nozzl~s is anlicipaled to 1>e

insufficient to maintllin effec~ve injection di<iribntion and volume COnTroL his anlieipaled thar

1hJ$ would significantly reuuce Ihe NOx emissIOn reJuclion perfonn~noe eonsi;tcnlly "ChleVed On

a SUSLainabJe basis.

The lack ofexperience wilh oyolone boilero, ~specialJy lhose Gring coo.l wilh SO~Cre deposilion

oharaolel"istio, such as NQ"h Dukola ligmie, makcs thi, leehnolugy leclmiOillly infeabibJ~ for application

on Lh~ MiHan R. Yuung Slalion Unit I boiler.

A.1.3.3 Rich Reagent Injection (RRI)

Rieh Reagent Injection (RRI) is a NOx control process thal h~s been developed and demonslraled

specifically for use on cyclone boiler,. Rich Reagent Injection IS an SNC'll process thaI iovolves lhe

injeclion ofaqueons urea into lhe lower furnace belween Ihe oyclones and the SOFA pOri(;. RRllmgels a

high 1~1llperntllre, fuel·rich ZOne wilhin lhe boiler-fumace enviromnml imrrn:<lialely adjacenl to lll~

oyclone hurners, and requires tempernmrcs in the rang~ of 2400 (0 3 I00 degree, F.

The three zones ofa Rich Reagent Injeclion SNCR applieauon on a hoiler wilh sep"-rnled overfire air are

shown as a ,ectioaal side e1evalion vi",,' of!he n.lmace in Figure A_l-4.

Dum, & McDunndl AI·2U Mllwkola Power Cuuperative, loc.
APPENDIX Al

Technical Feasibility Asse_"ment Details for NOx ('.ontrol Technologies

NOx HACT Analysis Study

OFA BumoufZone

N

Chemical

Injection

Fuel Rich Zone

Fuel Staged

Combustion

Zone

Figure A.1-4 Rich Reagent Injection Application on Boiler With Overfire Ai~

The Rich Reagenl Injeclion (RRI) process has been successfully demonslrnled On al least two eyclonefired hailers, wilh Ihe mosl recent installalion at Amercn's Sionx Unill, a 500 MW hoJlerfiring a hlend

o[PRB and mIdwestern bituminous coals, Generally, the heal content oflhese coals typically varies very

lillie- ShOrl-lerm lesting of the RRI process has been performed alone and in comhination with SNCR on

B.L England Unit 1 in 1999"''', and more rcqmtly alAmeren's Sioux Unit 1 in 20022l.l', in 2004"

(alone), and in lhe flfslhalfof200S" (alone, and with SNCR).

The RRI process is intended to be used only with air-starved (suhstoiehiometric siaged-air) cyclone

combustion, in conjunction with the installation und operation ofan OFA syslem. The RRI process ha.

nol been demonstraled On any nnilthat fires North Dakoll1-lignire. As of May 2006, no commercial

installalion ofa permunent Rich Reagent Injeclion system has been made al any cyclone-fired boiler_

MiImkola Pownr Coope,rnive, lnc_ Ai-21 Bum. & McDonnell
NO~ BACT AnalySIS Sludy APPEi\'DIXAI

Tedmic,j FeasibIlity Asse"mcnl DetaIl., for NOx Control Technologic,

-._--

TlKTe" only OIle holder o[ a comrnenaal license fOl modeling and cOIlcepluaily designing: RRI (Reac1ion

Engineering- InlernUlion,i), wllh lWO vendors sUh-lieensed to design and sell RRI cquiprnelll (Fuel Tech

and CombnSlion COlnpom;nl' Assoeialcs). Since these heense agreemcnl' me in place, and considering

lhal :;lIc~cssful dcmonsh'alion IcsImg ha:; bcm performed ullWO cycinne,lircu bOller powerplanls. lhi,

technology i:; considered to be appheab!e and commcrclally av"l.blc for potenli.l applicallOn on cyelone

boilers winch burn coals wllh hcal comcnls lh"l are relatively constant. Howcver, due lo lhe ,'"riahle hc,.l

content orIignile coal, RRI is conOldcred to he technically-in feasible for "ppl ic~twn on Norlh DakOl<!

lig" ilC·fir"J boilers. Tcchmcal Lca,ibil, ty ami expecled NOx emissions from RIU for appJicatlon On the

Millon It Young Slntioll Unil I boiler are induded in lhc "Luyeroo NOx R"ducIIon Tcchno]ngid'

sec lion.

A.1.3.4 Selective Catalytic Reduction (SCR)

The lowe..,t MOx emisRion levels from coal-fired utilily boilers are rypicaHy achievecl by in,lalling and

operalmg ocI""live cal>llyli" reducrion (SCR) ledmology. In ll,e SCR proc,,"'s, Ihe gaR slream iR pa"ed

thL'ough u calaly,t bed in U,. presence of ammoni~ lo rednoc NOx 10 moleonlur nitrogen and w.It.--,-. The

process is lennoo ">cl ective" lxx:anse the anunonia preJCl\:nlially reacl' M(h the No,., ralher thun with lhc

oxygen in thc flne ga,. A cutalyst is lIsed 10 enhancc NUx reduction ancl ammonia ulilization at

aPPrOpriale fine gas lc'TI1peramres. SCR is u:;ually applied 10 Due gas in lhe 600°F to 750"F tempemtlue

range. There are vnria~onR in Ihe SCR proccss for ooal·fired bOIler<; lhaI mostly Involve locations In lhc

Jlu" gaB path wh"re the calalysl is plao"J in order 10 promote Ihe desirecl NOx emISsion I'educliou erfed.

These are dcscTibed below.

A.1.3.4.1 High-Dust Selective Catalytic Reduction (HD-5CRJ

For coal"fired hoil"'s, • convenlion.l SCR reaclor nlilize:; readily-ava,lablc c~l>lIYSl m~lerials and reagent

In lhe form of arnmonia_ A conventional SCll reaotor '" commonly ins",Hed in a high-dnst, hal-side

aIT~ngemenl. located bClween the ecunomiZi'r ouJe[ and air healer inlel where lhe nne gus lempenllure;s

within the de."ed operallng ranI,'" for lhe SCR catalyst The convenlionn! SCR reaClor arrangement is

preferred for mo,[ coal-fired applications in nlilily boilers hecan<e ilnvoids lhe aclJed expen:;e of

rehea1ing Lbe nue g~s ifplacoo alIer the air heatel'S whi"h cool Lbe flue ga,. and down,[ream of.ny flue

gas treatmenllO remove aCid gases_ Conven~onal SCR technology uses an ammonia injeclion grid

(AIG), which consist, ofmnltiple nozzles, [or dislnhuling lhc reagent inlo lhe flne gas al lhe boiler's

economizer fine pis onllel.

Burns &0 McDonlloll Al_n Minnkola PowerCoope",'ive, Inc.
APPENDIX AI

Technical Feasibility A"c<smenl Derails for NOx Control Teclmologies

NOx BACT Analysis Sludy

A schemnlic graphic diegrnm for a conventional high·dusl, hoi-side SCR system on a boiler with a flue

gas dcsulfurizalion systcm and stack gas reheat is provided in Vigure A.I-5.

Figure A.1-5 Convenlional High-Dust SCR Arrangemenl

with FGD Scrubber OutJet Reheat

High Dust Arrangement

CD Steam generator

® Regenerating heat exchanger

@AJr

o Electrostatic precipitator

® S02 - Scrubber

® SCR - Reactor

ill Catalyst

® Vaporizer

® Ammonia I Air - Mixer

@ Ammonia storage Lank

(figure copied from vrheelahralor Air Pollution Controlliternrure)

Conventional high-dust, hoi-side SCR technology has heen installed on severnl pulverized coal and

cyclone boilc<ll firing bituminous and subbituminons coal in lhc Uniled Slales. There are ..Iso a limiled

number ofEuropean SCR iu.....lla!ions on sleam eleclric generaling units (SEGUs) firing lower grade

(brown) coal. Thcre are, however, no existing full-scale SCR installalions on units lhal fire North Dakota

Minnkot. Powe< Cooperative, Inc. AI-2l Bums & McDonnell
NO, BACT "'nalysi' Shldy APPENDIXAl

Tttl1J1icol Fe.sib,liIj' Asse"monl Dolail. Jor NOx COlllrol Tcclmologio'

lignile. There are approximately 50 cyclone-fired uroit, 10Clltcu in lhc SMe,; ~lTccleu by EPA's NO, SIP

calL Over half of the.,e units nre pl~nning to insl~ll convem,oLlal high-dust, hot-side SCR systems in

rc'l'0nse 10 lhe SIP call, The in,tallalion of conventioml hi gh-uusl, hul-SHk SCI< 'Y'lems has heen

cornplcl~d on apprnximtllcly 22 of the'e unit,. Appendix A2Ii'IS sew",l eonvenlional hIgh-Just hot-sid~

IJ.S. SCR inSlOll"lions on pulvetiu:d coal anu cyclon~-lircd utility boilers, along with measured NOx

cmi"ions. Inilial dala fmln Ihese unils indicate thm conVenIlOl\a] high"dusl, hoi-side SCR syslems

operaled on .'Ullilhlc cyclone-fired unil~ muy bc ublc 10 reduce NOx emi'''ons to as low~, 0.07

IbsfnlTnBlu, Several SCR iLlSLallnlions have been retrofit on eXLSling cyclone.fire,l boilers buming:

we,lem subbituminou, coal (or PRE blended wilh midweslem b,luminou:; coal). For cyclone coal-nred

utility boilers rell'Ofi tled wilh SCR technology, all wcre ong:inally dC3lgned 10 burn h' tummous coal.

Thc EPA NOx Sil' call only applies to units in lhe eastern Uniled Slalc.,. Th= are no facililies firing

Norlh Dakola ligmte in Ihe EPA NOx SIP can region. SCR sysLem operution is currently only needed

during the ozone seaWn (June _ Septemher) for units insl"lling: eonlrul equipment "olely to meel lhe EPA

NOx SIP call requirements. Limiled annuuI op"'Iation is a ,ignificant factor WJ th respCCI 1o SCR

equi pm:nl reliability, mamtenanee, op..,,;llonal cos'.s, and catalY't life. The dem~n<l" on !he SCR By,tem

are much mor~ severe irlhc C<luipment is required 10 OpetOlC On a full-linm, annual basi,.

Two hyprnduc!:S fromlhe high-dusl, hOI-side SCR process are ammonia slip and SO,:

• Ammonia Slip, Slip is ammonia lhat is unreacted in Ihe NO, emission reduction proceQ;.

Maximum ammonia slip for a gas !ired unil is "sually 10 ppmvd whereas, on a coal fired ""il.

ammonia slip below 5 ppm i.' desire,l For certain applications, this concentration Can be

problemalic, therefole requinng more catalysl to reduce slip. MoO' new SCR "pplications have

ammonia slip gu~run\ced at a 2 ppmvd mnximum for an inili.l opemling period.

• SO,: Due to lhe compoSltion oftypieul SCR calalysls, a small percentage or mh~TI:nl so, w,11 bc

o,,,dizcu 10 ,,0,. This oxidation can he controlled by carul)'s1 sekclion anu can he Ie,s thon one

percenL SO, 1o SO, oxidation mUSI be carefully controlled to avoid crealing SO, levels suf1ioienll)'

high to rai,e th~ possihility of aIr healer fonling. A unil filing high_sulfur ~oaI with SCR

tedmol ogy is cspcci'dlly vulnerahle [0 SO, oxid"llon and ammonia slip.rela ted fouling problems.

Tho deposition and fouling is dne to formation ofsolid ammonium s"lf.le «NlI,},SO,) and liqnid

ammoninm bisulfalC (NH.HSO,). The most important de3ign variable is optimi2ing lhe oaralysl

seleotion ~nd amonnt ofoal:ily'llhat will reduee NOx emissions, conlroI "nllllonia slip, and

minimize SO, oxidalion.

Burn< & McDonnell AI_24 Minnko"'- Power Cuope, a!lve, Inc
Al'PENDlX Al

Technical FC"-,Ibility Assessm""t Dctail, for NOx Contrnl TcdmologioOS

NOK BACT An.Jy,i, Study

-----------

Recenllechnology has allowed cUlalysl suppliers 10 makc mOre rigorous amI lenglhy guarantees. A

reasonable inilial operaling period lor convenlional cataly'ls in high-<lust rcacLor ammgemenls on boilers

firing eastern ormidwcstem hiluminous coal is uround 24,000 activc opemting houn> (Le. when ammonia

reagent is being injecled). F"cIOrS thai need lo be laken inlo aooouni in dc~ib'll ofa high-<lusl, hol-side

SCR application lhal affcolthe neoo for cawlysl replaoement are:

• Pressure drop: The ,mount of re.,lriction 10 flue gas flow through Iho SCR inlet, OlIJImonia injeclion

grid, SCR r03Clnr, and dOWT1slrc~m ductwork directly incrcase.s induced dran ran horsepower

required lo mainlnin adequale boiler clrnfl. This is an importam parameter to consider ~nd minimize

cluring the design stage. Pressure drop is a function ofthe avemge and maximum SCR reactor ducl

velocities, the amount ofrc.striction caused by flow distribution com:Clion deVices (bames or

vmes), and Ihe number and gcomelrical aspects oflhe c"lalyst layers. Many retrofil SCR

inslallalions Tl.XJuire a booster f"n or upgraded induced dmft fan 10 overcom" the added now

resistance. This increases operating cost for the increase in auxiliary power consumption and loss

ofsaleable electric J:'0wer..TI,e type and pilch of tho catalyst arc factor< mosl influenlial in

delermining lhe amounl ofpressurc dMt~

:>- CalDly" tYPe: The mosl commOn lYpe, oc fonns ofca1.:l1yst material arc honeycomb or plate.

The fonncr offer< more surface area pec volume, bul can be more restrictive and pron" 10

pluggage from ash deposits. TIle luller is usually les.s restriclivc but requires more catalyst

per layer or more layen; to achieve Ihe active surface needed 10 "chiove the intended NOx

cmission reduction.

" Ca~-l1ysl Pilch: The pilch oflh" cUlalysl, a tenn u..ed 10 ,Iesoribe Ihe size of tho gas patb

openings IhlOUgh lhe catalyst, varies ,Jcp~'Tlding on U,e manufacrurer and dc:sign duslloading.

Pitch is generally On lhe order of5 10 7 millim"lers. POlenlial pluggage offlow channels

wilhin me cataly,ts layers is thercfore an issue thai muSI be dealt with during design.

• Calalvst performance' Tbc amounl of NOx cmission reduction e>:pccled is a funclion of Ihe

specific activity level of Ihc calalysl rnalerial and the arnoum of calalyst installed, over a given

period of time. Calalyst (onnulalion selcclion and fealures ofconslruclion bavc a signifi"ant

impact on long.lenn NOx emission reduotion and subsequ~'Tltcosls for =g~"TIl and cala]ysts

replacement. The frequency of catalysl replacemenl is influenccd slrongly by:

" Calah.;t ern.sjon: Erosion of Ihe calalyst mnlcrial in coal fired units from entrained nyash or

scotblowing action reduces thc amowli of active surfaoe available for rcacting with thc

reagent amI flue gas, and can cause distonions in gas distribulion (~challllcling'') through Ih"

Minnkota Power Cooperative, Inc. AI·2S Burn, & MeDonnell
NU~ BACT Analysis Srudy APPENDIX Al

Technical Fca,ib,li'y Assessmenl Demils rOT NOx Conllol Tco~nologies

SClt r~""c(or. Ca(aly.,t mnler",l is fwgilc and can 11e easily damaged. Some caLalys( is

provJded with =ion-resislan( top edges 10 miligntc (his ("I\dc"cy.

:>- J'\:loistur_e nhsoQl(;oo: Many types of calalyst are ~nmnge~ hy ah,orrtioo ormui,lure. Tho

reae(or mllsl be kept above "",hien( dewpom( (emperalures or protecled from Ii ee~ing during

outages in Older 10 l'rollL"ellhe eata[y,( from moiSlore damage. Spore calalyst mllsl be

carefully p"ckagcd lD keer il dry and mu,( bc handled deliealely to prevent danmg~.

:>- Thl"Trrml degradi'.IJl'ln: TI,e :;peeifie aelivc demenL' "I· the carnly.'l Hurlaec, o. lhe malrix

struclure il,elfupon which the calalysl malenal is "pplied, ean dcgw,lc when exposed lO flue

ga, lellLllemlllrcs grealer Ihan lhe IIlleLlded <IeSll;Il of thc formulation. J-hgh flue gas

lemperulures wilhm tile reaclor causes oinlering, leading to a permanent 10""' of cntalyst

"OllVily due 10 a change ltl the poro siruelure orlhe catalysL Proper ,eleclion und

manufac(uriLlg eonl",1 of the cat"lysl slructure nn,1 formulalion can minimize Ihennal

degradatiO<\.

;» CaLalYSI poisoning: The los" ofperlonn"nce or acllvily ofIhe calalyst over time C"n be due

10 chemical damage or 1'0;""niTlg. Two clements e.,pecJally derrimenlal to Ihe life of commOn

ti~mium-surponed vana~ium pcnl()xi<!e seR oaLalyst are arsenio ami zinc.

Vanadiallunf:.\len_bascd calalysls are I'arlicul"rly susc~"pllblc 10 rapid deaclivJIioH duc 10

gaseous al1>Cnie poisoning. In some German sen. inslallalions, a 50% 10.'.' ofaOI;vity ha"

betn reported wllh", 10,000-15,000 upcf"ling hour.<. Addilion of molyl"fenllm 10 a vana~;n"

lil"nium SCR calaly.'l On Olmilar apphcaliom "hows relalivc oClivily TC"{llIchon" of20_25%.

Progre"sive loss ofSeR NOx redUClion performance from C<1lalysl deactivalion due 10

pOl"OnJrlg is nul possible 10 re.,to, e w;lhoul dTecllve cleaning 10 remove the deposils, or

evcnlual replacement.

)- Catalyst fouliJ)g: The surface me" polenlially oxposcd 10 the rc~g(."Tlt (ommonia) and nitrogen

oxides in lhe flue gas t~n bccome fouled w;lh flyJsh ur ,ulfllr-relaled compounds_ The

presenoe ofexCcss calcium oxide", Ihe presence ofsulfur in lhe flue gas can jonn a calcmm

~ulf"le surface coating Ihol Con be eXlremely densc, Tll,,-,king Ihc pores of the c<,llllysL

Pro~e"sive 10"" ofSCR NOx r~d\lclion perfnrm"nec from calalyst deaelivation due to

fou]inl\ is diJIic\l1l10 re"lore withoul dTcclivc cleaning to remove the deposits, Or evcnlunl

u-placement.

SCR lcehJlology ],n~ boen inslalled on numerous eo_l-fired ulilily boiler meil ilio, around tbc world nnd

thc,c "re " I"rge numb"r ofmanufacturers lhal m,uke! lhe onlalysls_ Tile queSlion i, ",hclher SCR is a

i;·

BUIlL' & Md)om,dl At-1G Minnkul',l POWl., Cooperdlivc, 1"0.
APPENDlXAI

Teehn;",,1 Feasibility A,.,e"mem Delails for NOx Control Tedmologies

NOx Bilef An,lrsi, Study

feasible lechnology for a unit firing North Dakota lignile. There are scnous concerns whcther insl"llalion

of SCR leehnnlogy On " North Dakola lignilc"fired unil ean be successful, cspeeially in a convenlional

"hOl-side, high-dusl" configuralion_ Thc effectiveness oflhe SCIl proccss is highly dependent upon the

ability ofIhc nitrogen oxides in the nue gas being able to eonl"Cl the aolive siles wilhin microscopic pores

orthe catalyst in lhe presence ofammonia reagent with minimal interkrenee from conlamimmLs.

A recenlleohnic.,l puper "A'h and Mercury Behavior in SCR Calalysls When Firing Subbituminous and

Lignile C""ls" by the Energy & Environmenlnl Rcsearch Cenler (EEIlC) of the University ofNorth

D"kol" was puhlished in lhe FebTllary 2005 issue ofFucl Processing Technology mugao,ine"_ This paper

summarized Ihe resuhs of SCR slipslream te.,tmg al two PRE-rITe,1 p]an~' and one Norlh D"kol" lignilefired powcrpbnt. The evaluation incloded delenninalion ofimpacls ofa<h on SCRplugging and

blinding. Flue gas WaS isokinelically exlnleled from lhe convective pass of lhe hailer upstream of the air

h"ater. Pressure drop across the calalyst was measured during lhe initial two-monlh teSl period, and lhe

two conseeulive two-monlb leSl periods following lhe ini!i~llrial, while holding fluc gas flow and

, "~~empernturcs Constant. Ammonia WaS injecled dOWIlstream ofa screen, ul'-,tream of a flow stmighlcncr

c-and air pulse scclion. Compressed air w"~ i'liected ahead ofthe reaclor, and was periodically pulsed 10

simulate sootblowing to minimize ash deposit aecumulalion_

.This slipslrC-llm SCR lesting examiTIed the significanee of ash accumulations on SCR calillysl on botb lhe

macroscopic and microscopie levels. Very small flyash particles ",ere found bonded logelher by" matrix

ofsodium-, calcium-, and sullur-rieh materials, likely in lhe fonn ofc"lcium sulfale. North Dakola

lignile coal contains mauy alkali and ali<aline--earlh clemenIS, ~nd suI fur. The firing oflignite coal which

produces fine ( less lhan 5-/tm <liameler) l1yash particles creates condilions lhat enter th" pores (If Ih"

catalyst, rc,ct with SO, in the flue gas, and form sulfates which bind olher ash particles into lhe matrix.

As poslcd On Electric Power Research Inslilule Inc. 's (EPRI's) website regarding the impacl of eoallype

on SeR calalysl 1ife and penorrnancc, a recenl EPR! sludy'" produccd field dala analyzed from an ''InSitu Mini SCR Reaclor" system installed in a typical ''!ligh-dust'' location al seven differenl lesl sites,

inclucling four firing PRB coal, one firing Texas lignite, onc firins high_sulfur eastern biluminous cool,

and one firing 3 PRE/easlern bituminous coal blend_ ·!he PRElbituminous coal blend lest was performed

~t ArnerenUE's Sioux Slillion, on one oflhe lwo 500 MW cyclone_fired boilers_ This sludy found Ihal

Ibe cyelone unit firing lhe PRBlbiluminous coal blend exhibiled the fastcsl ratc ofcatalyst activity

degradation. Also, the higher deactiv.lion rates seen at this SilO were due lo economizer exil nue gas

Minukola Power Cool"'rativ~, Inc. AI·27 Bums & McDonnoli
NO~ BACT Analy.,;, Siudy i\T'T'ENDlXAI

Technical Fea,ibilily Assessmenl DeLail, rOT NOx Control Teoh"ologies

I~mp"njl"r~" bcmg >l!,'11ificanlly high" Ihun nl Ih~ other Sile.,. A comrariwn of U,C Texas lignile and on~

of the l'llli-fired sHes wilh Iwo differenl catalysis, deaclivalion WHS mOre n funelion oflrace el~m~nlS in

Ihe [Jut ga~ unu flyash Ih"n Ihe "pccific c"wlysllype Or formulation.

Norlh D"kol" ilgnilc prouucc""n "sh th"1 i> vc-ry >Iicky and CT~"I<:S s~v~re a,h depo,il;on prohl~ms.

There hav~ heen l\0 inslallatlOns of SCI{ systems (filII-seale) on unils lhat fITe Norlh D"ko~, lib'llilc. A

Icchnioul ''"S''"mcnl wa,; eon,!<wled for 1l1e iTl,;lalloliOJ\ of SCR lec1mology on a North Dakola ligLlite uml.

ln orueT 10 further cvalualc Ihe fcaSlbihly ofin>I"lhng" convention;!1 SCR ~ySlem OIl a Norih Dakol"

lignLre fired unil, the Energy & Environmenlalltesearch Ccnler (EERC) "Ilhe Univ~TSilyofNorth

DakoLa wa, eon,ulled. EERC has exte",ive experience Ulve'l;galing lhe deposilion characterislics of

Norih Dakota lignil~ a,h.

Tedmical difficullies anu anlicipHlcu operalmg problems thai arc "mCbolv~u w,lh TI'&pc",llo imlalling

convenlional SCR technology al Millon R. Young Stalion include lbe imp"ols of cTOsion, ,evere ash

deposition, and "popeorn ash" on the oatnly,L According the EERC" study (""e Appendix il), '1he mOSI

>ll;flificunl problem, Ih~ I prohibillhe ,uc~C$\ful or~rntion or SCR cnLnly.'l' LO lignire eoal " the rormation

of low-lemperature sodium-<:alcium-mab'lleaillln sulfales "nd pho,phalc" Ihal will form on Ihe "mf"ces or'

calaly,ls and the earryover ofdepo,lls Ihat will plug Ihe calalyst openings, Tesulling in inereased pres..,u'e

drop and decreased etfJcieney". For the,e reowns, aprl iealion of available convenl,onal hlgh--dusl SCR

kohnology is oonsi,jere<l Leolmieally infeasiblo lOr Millon R. Young SLalion Unit land Unir 2 hoiler>;.

These concerns oan be divided inlo four categoric,..bch c"legory is addrcssed below. An cxplanalion or

the faclors lhar make eonv<:JIlional SCR lechnology infcasible for Ihese boilers follow",

1. A,h Deposilion: Norlh DakOla hb'11ile conlains a vaTl"b1c .n(l eomplex variety of inorganie

compoun,],; Ihal conlribule lO a,h depO';lion. This fno] prod"e~,; a&h wilh ,~vere del'0silion

eharaclcTislics lhal ore nol Iypical wiLh olher coals. When cxposculo the hc"1 of Ihc combustion

process in"de the eydone burners, the majomy or ll,e rud ash h~"ome.< molten and flnw:; into Ihe

bOllOm onhe flJnJoco. A .,ignifie~nl portion oflhe fud nsh is enlra;n",l inlO the nu~ go,; exiting

lhe cyclone barrels at high velocity, wheTe it comes inlo conl"cl wilh lhe lower fum"ee

waterwalls. The porlion lh.l is curricd wilh Ihe rio,ing IIue gas ~oob and SOmc is d"f'Osilc<1 on

he"t Imn,fcr suTfuec, in the upp~r fum"cc .ml boik, conveclion pas>. Ash depo,ilion on heat

transfer surfaees is a subslanlial p' ohlem for ulllL, lhat fire North Dakola lignile. The problem is

so ,eve,e aI Millon R. Young thallhe Unil I ho;ler rllOsl1Je shul down nl 120.dny inI<:rv,,1s [0

Bum, & McDonucll AI-28 Minnkol' Po"'e, CoOp,,,.llVC, Inc.
APPENDIX AI

Tcrbnic,l Foasibility Assessment DClail, for NO~ Control Tcchnologies

NO~ BACT Analysis ~ludy

a]lo", for cleaning of ash deposits from Ihe boilcr heal trnnsfer surfaces in order 10 reslore

r"asuIlllblc fumace exit gas velocilies lind lempernlUI"S.

Sodium lS a signifi"an\ contributor to the ··slickines:;" ofthe ash pro<!ueed from firing Norlh

Dakol;] lignite. Sodium contenl of thc lignite ash av"rngcs approximalely 4.4%, and can nearly

double this value for Wme of tbe lignile produced from the Cenl~T mine_ PRE coal lypically

avcrages around 1.5% sodium conlenL Boilers firing North Dakota lignite typically have. 2.5%

high~T heal rale (million Bill per kilowatt ofelectric gencralion) than a typical boiler firing PRE

coal, thus ICquiring more heal input and firing more fuel per mcgawalt of electricity oulpUl. A

cyclone boiler ruing Nonh Dakota lignite also converls approximately 50% of Lhe fuel ash to

nyash, compared wilh 35% conversion ratc for PRB co.l-fired cyclone boilers. Overall, Lhis

results in an amount ofsodium ~"TT1ilLed from a cyclonc boiler firmg North D-dkuta lignite of

approximalcly 7.31b<!M~-hr compared wilh 0.9 lb,.lMW-hr for a PRB_fired cyclone boiler.

(-~ i'a;0- ;~.:; :'(, I r t', ~< t r4r-·-~1,

.... -'__ •.. The calalysls in coal-fired boiler SCR "",cion; are highly susceptible ).0 ash. deposilion_ 10 a

lypical ""nvention.l high-du'l SCR reactor, lhc flue gas !Y]Jical1y passes Ihruugh two to four

layers of catalyst modules. The c"lnlyS! modules have numcrous narrow pas",gcs 10 provide

inLimal" comaCI between Ihe flue ll"s, ammonia and catalyst The clearance (pilch) in thesc

1'''-'--'<3ges is typically 6-10 millimeters. A Iypical calalystlayer is approximately I lo 1.5 meters

deep_ The calalysts in "<lUl-flred hoiler SCR reactors mUSI be cleaned frequco,ly using soot

blow"" andlor sonic horns. This is lrue even on illlils firing fuels thal do not pruducc slickyash

lhal contribulcs to ush deposition. A>;h dcposilion on the calalysl in a high-dusl SCR appliealion

would be severe fora uni, liring North Dakolu lignile.

Sulfur in thc coal is oxidized dunng excess air combustion to form sulfur dioxidc (SO,). nnd a

small .mount ofsulfur lrioxide (SO,). Some oflhe ammonia-bnsedrcagcnl injecledupstream of

lhe SCR reactor will combine with So, lo form ammonium bisulfate. The CatalYSI in the SCR

reaelOT will also oxidize a portion oftlle SO, lo SO,. Excess unreacted ammonia r~<Ig<:m

carryover (Uammonia slip") from the SCR rcactor will also reacl wilh Lhesc sulfuric acid

compounds in a similar fashion. The deposition eh"rnelcriSlies for a unit burning North DakOla

lignile will C"<Ile difficull-lo-remove ash dcposils nnd plugg.ge ofa conventional high-dusl

cnlalys~ and increase the probability Lhat Ihe air prchcalcr downstream and fluc ga, duclwurk win

bc pronc LO accumulalions which could be severe. High-dusl SCR performance and calalysllifc

Minnkota Powcr Cooperalive, Inc_ AI·29 DllIns & McDonnell
r-IUx HACr Analysis Smdy APPENDIX AI

TedUliool Fcosihilily A.~,c"mcn( Dcloil" lor NOx ConlTol Technolo~ic.,

will be ,cvcrely impacted, U is anticipated Ihal a high--<Jusl Sell', ca~,lyst lifc will bc shorlcncd

from J-6 years (lyrical) lO as linle as 2_12 monlhs, requiring ""'ended, freqnenl oUlages for

rcpJacrmcnl.

Hol-,idc "iT pTchealers me suscepl,ble 10 fooling. Tobol"r air prc hc"lcrs originally ,upplied wilh

all cyclone 110ilers alw loleratc mu<1cmle duslloadings, since Iheir heir-hi and .,ize make Ihem

,hffieull lu m"inlain clcanliness, Leak lighlncss of Ih,- "iT prehc"lcT IS imporlanl on cyclone-fired

boilers w,lh relalively hJgh forced drafi: iim discharge (combllslion air supply) pressures, A highdust SCR installation will be prone lO aJr I'reheaIer tube ioulmg and I'luggage, requinnJi

e'<lended, ircqut-nl uul"I,'Cs fur ckamng.

2. ·'Popcorn Ash": A second con,ideration in the "pplication of convenlional high-<lusl SCR

technology on a ligniIe--lired "nil is Ihe 1'01enlial of the SOl reacmr caruly,tl'lllggage re,ulling

I,om carryover of"l'opeom ",h" from Il,C I>o;le"- nOJlers iiring Norlh D"kola lig";le h"ve ,cvcre

problem,; wilh ",h oqlOsilion on boiler smfaccs. Norlh Oak"I" lib'llilc h"s a high propcnsily 10

form d,·po,ils on Ihc bOller's furnace and convcction p"" fIreside ,udaees. For hgnile-fired

umts, the hoiler'., heal lransl"r sul'isce' .om, he cleaned by s""lblowing and Olher method" (",I;,

waler lances) Ireqll"nlly 10 m",n(~in SOli.iaclnry holler oper-cilloo Some of Ihc removed dcpo:;ilS

Tc1ea""rl by Ihc clc"ning "clion wilhin Ihe boiler and COl1vcciion pH&<:' form ·'popcorn ash",

whleh wlll bc lTllrnillCd in Ibe flue gas. Cany OV~T of b01 kT ash deposits wil! conllibute 10

pluggage of the ·'popcorn ..,h" sereen ahead ofIhe top layer oiSeR reaclOr CaLaly'L This Can

call,e diSlOl'liOnf. in gas di<lrihutlOn ("channeliLlg") lhmllgh the SCR r""clOr, which will agj,'r.,v;,le

erosion in Ihe high vcloelly arcas ami ineffcclivc perfor","nee of Ihe ~"t"IY'I.

3. Temperature: A Ihird issue Ihat impacls the feasibility ofinslalling high-dust SCR lechno]ogy OJ\

lhe North Dakola 1ign ile-Jired llnils is "al~ lyst ope' aling temperature. TI,e perJormancc "fany

SClt cululysl is highly clcl'endenl on Ihe lempcn,lurc "f Ih~ flue gas passing Ihrough Ihe reaclor,

Typl"aJJy,;, IcmpcTalun; of600 - 750 deb'rees F is Tequircd lu obl.in salisfJclory opera lion ot'an

SCR reaclOL Operation ofoommonly supplicd cnLaly,t SllJ t:lblc lor a high-{h',1 SCR Tcaelor al

Icmpcn,lures above 750 degrees resuUs in severe and mpid delerioratiou of Ihe caLaly.'l "rid SCR

re,clor·s NOx emission ,eduolion perlol'mance, For bituminous and suh-hilununoll, coal_r,,,,,l

uniL', hoiler Iluc ,~a, pussing belween Ihe cconurni~~r o,nkl unll air hl"I~T inlel is ~l'I1e]'Jlly

Bum, & MeDoJllldl 111-30 MinnkolD POWIT r-nopeoalive, h,e.
APPENDIXAI

Technical Feasihilily A,sessmcnl Delail' fot NOx Conlrol Technologies

NOx BACf Aoaj~sis Slndy

~.,

.. ~._- -. . ~-

within a lenlpernture range acceptable fur convcntional SCR cUlulysls without auditional heating

or cooling oflhe flow stream.

North Dakota lignite-fired cyclonc boilers, including tho,. al Millon R. Young Station, have high

temperatures at thc cconomi.",'s flue gas oullet by <lesign. The highcSl g"-' temper~tur~."

downstream of the cnnveclion pass cconomi:zt:r sections and upstream of lhc "ir heater inlets in

Mihon R_ Young Unit l's boiler are much higher than 750 degrccs,

Iligh gas tcmperatures at the air hc-ater inlet arC required to produce the high air tempera lures

(700°F) needed for the pre-combuslion lignite drying system, ulo"S wilh primary and secondary

combuslion "ir supplied to the cyclones. Such air preheatcr ;nnmgemenL, and c"pabil ilies have

be~Tltaken into account in the de.,ign OIlhc North DakOla lignite-fired cyclone boilers. Reducing

this high gas ",mpernture to accommodate con ventional catalysts for a convcmional high-<lust·

SCR r~-aClor would result in prc-combuslion air tempcrntures thaI are too low 10 provide

.. _.~~lisfactory <!..TY!ng a.!'~ rapid ~~~~on._?~~":e_h!gh-moislnrefucl. This will ,e,;ous)y impact

reliable combustion, ,lag formation ancl tap ping in thc cyclone burners. Consequently, it lS not

fcusible tel medlfy the MillOn R. Young Unit I's boiler 10 opernte wilh the lower economizo.."T

oullct flue gas lemperaluTC,

C.talysts for a convenlional high-<lus" hol,-side SCR 5)'.,tem havc nOl been installc<l nOr

successfully demonstr"lc(1 in a lull-scale installation of an operaling soli<l [oeHired unitlh"t are

designccllo conlinuously Opl,"te al the high lcmperatures (above 750 degrees F) lhat exist

between the conveclion pass economizer and air heater on lhe Millon R. Young Unil l's boiler.

4_ Erosion: A final considcmtion on whelher hot..o;ide, high_d~t SCR technology can be succcssful

on a North DakOla lignite-fired unil is lhe potenlial for ero~ion oflhe SCR calalyst. North Dakola

lignite supplied from lhe Cenler minc has an avcrugc fuel ash contcnl of 10.5%,.Jtd can have an

ash contenl up to 25.5 percenl_ PRll coal fuel ash content lypically averages approximalely 5

percent. As previously staled, a cyelone boiler firing North Dakota lign ile converts a

sign,Jicanlly greater amount offlyash than a PRE-fired cyclone boiler. OVCT1!II, lhis results in a

flyash oUlput mle from a cyclone boiler firing North Dakota lignile ofapproximately 83 lh.,/MWhr compared wilh 21 IbsfMW"hr for a PRB_fired cyclone boiler. High ash eunlenls in the flue gas

stream can result in physical erosion of thc calalyst. In addilion, effective on-line cleaning of lhe

Minnko,a Power Cooper.rivc. Inc. At_3t Burn' & McDonnell
APPENDIX Al

Tochnicol l'eaSlbilily A.,,",,,,menl Delails for NOx Control Toohnologies

high-du~1 c;ll"ly,1 will likely r~(l"irc stc"m or eumpressed mr soolblowing. Cle'nint: cydes of

Ihe ealolysr will be required much more frequently lhan a typJcal convenlion,,1 SCH. in"(.llalion

due to Ihe ",h dqx),i(ion ehar~~(LTisliesof the Nor(h Oako(" Ii gni(e ~nd rhe expectoo buildup an<!

plll!!".gage re.,ulrirlg from lbe caroy O~er of "p"peom ",h". FTe(jllcnl sootblowing ,,) Ihc c;,("ly'l lo

remo\'e fouling deposit" arid ;"h accumulation" will conlribu(e (0 erosion ,md dccreased ca(alySI

lifc. '] here '" .wme E"rop""n experience wITh hil~h "sh brown eOill, thal calalY"l manuf"c(mers

WJIl he abk lO umw upon. ·n,i., e.~pcrien"c, however, ""II not be direcrly 'pplic"ble to lhe.,e

Unite,,1 St,,(cs um ls beeau.,e of lhc severe deposition chaJ<lcleri"ies of(hc North Dakol1J lilllll("

osh comp.red (0 brown eo"t.

The EPA's N,sR M~nllal ,I"lcs (hJ( 1,,1' n lcchnology (0 be k"siblc ,( must "av.iloblc "nd ;,pplJcJble".

SCR lochnology i" "n JVJilable technology which hJ" been instJlled on numerous powel'jllam faeililie,

around (hc world "nd lhere al'e a l;Jrge number of manufacml'er.' lhal marke! the technology. The q"e'lion

is whclher SCR (echnology" '·applicable" Ii'r a unil flrinR Norlh [)akOI;, li~ute.

In accordance with EPA·, NSR Man",I," (cchnology i" ""pphcablc" if Il has htL"Tl msl<llled on a ".,imil"r

urn l". HOl-side, hIgh-dust ,sCR 'cchnology hoo been I'el[olll 0[\ coal-lir",l "IIlls fealuring oyc1"n~ bOllers.

However, there are no ,sC.R m,lall"llOns in op~mllOn Or pl;Jnnod On unit, (h"t include cyclonc burners

firing North Dakota lig"i", wllh severe "logging ,mu foulmg 1"ndcn",C' combined wilh ",ch hIgh boilel'

economizer outlcl gas lemperatures (over 150°]-') rcquired for high-mOlslure tue] prc-dry;ng sy"(ems anu

(ububr "ir prehe"lers_

The EJ'A's N,sR Manual abo sl"tes a tec1mology m"y bc ,lctemum;d (0 be nOl applicahle ,f'·" ledm;cal

a"",---ssmcnl ~onsidcTing physicJI, d,eml";l! Jnd engineermg pnllciples andlor empiricJI data showing Ih"

",chnology would not work on the emi"ions unil und~r review or Lha( un"oh'"blc (edmical dJijicullle,

would prccludc (be "ucce""lul dcploymen( orthe technique_" Tn (hi.' ,sCR lechnology apphcntion, i(

appeal" lha( a faeili ly ulili(y powerplant llring North Dako(" hgnilc wOllld experien"c extended lime

delay" or he requirc,! to devote signi lioanl intcrn,,1 resource" and engJge ontside rescm"h, followed by

extended field (riJI" to leam how lO "pply a conventjona!l,igl,-dust, h 01 -side SC'J, (echno] ogy on 'J stich a

Iud sonroe.

Based upun lhi, lechnical a",e.\.Sm~nl that looked allhe \'ariolls de,ign ilnu op.ralion~1 i",ucs as.,ocialcrl

wirh the 1Il,tJllJlion ol"hol_",ue, high-dusl SCR teclmology on a Nm(h Dakota lib'Ilile-fired sle.m_ok"lric

Al_.12 MilUdwla Power rooper.llivc. Inc.
APPENDIX Al

Technical Feasibility A",e=t Detail, for NOx Conlrol Technologic,

NOK BACT Analysis Srudy

generaling unil, lhis conlrol oplion is considered technically infeasible for Unit l's boil~T al Millon R.

Young Stalion.

A.1.3.4.2' low·Dust Selective Catalytic Reduction (lD-SCR)

Low-cluSl SCR (I.D l>CR) lechnology could potcnti~1Jy he applicable 10 North DakoLa lignite-fired boilers

lor NOx emission control. Low-du<I SCR refer< lo the location ofthe SCR syslem dUWIlslrcam ofa

p~rticolate colleclion syslem, such a, an electro,tal;C precipirnlor or a fabric filter. If Ille low-dusl SCR is

dOWIlslream of a hoi-side eleclrrn;talie precipilalor and prior to the air prehc~ler, nne ga., reheating is

unnecess"JY. TIris hag been the prevalenl fonn of altemaliv~ retrofil SCRs in the Uniled Slalcs fur coolfired utility boilers. 'rherc arc len known hoi-side low-dust SCR inslallations (willloul flue gas reheat)

opemling in the Uniled Slales ag ofJuly 2005. The...., are listed in Appendix A2. Ifapplied lo MRY

Slalion Unil I '.' hoiler. lhe low-dusl SCR equipmenl would be downslream or a cold_side electrostatic

precipitator, nue gas reheat prior to the 1.0 SCR reaclor inlct would be nX]uired for proper NOx erni&,ion

reduclion pcrfoITIlllnce.

For u cold_side 1.0 SCR, the ESP oullel flue gas passes lhrough a low-dusl gas·to·gas heal exchanger (ill

GTG-HE), prior to passing lo the low-dust SCR reaelOr. Aller the LD GTG-HE, Ihe flue gas will travel

lhrough lhc new duel, receiving hot nue ga"es from a direel-fired gas burner or set orhigh-pressurc Slcam

coils, leading lo an ammonia injeelion b";~, lurning vanes and Lhcn inlo the I.D SCR reactor. The flue gas

eniding lhe inlellolhe LD GTG HE is expecled [0 be near the air heater OUllellemperalUre (330-J40"F)

in a cold-side I.D SCR application. The supplcmc"1Ilal heal added dOWTlSlream Oflhe LD GTG_HE can be

SUl'rlied from high lempernture slearn coil., (indirect beal e",ehange) or directly from naturdl g;,s-fired

duct hurners. The flue gas must be heated [0 a minimum ofapproximately 600"F for lbe ill SCR NOxammonia reaction lo be effective. The LO gas-m-gas heal exchanger is wed lo recover pari ofthat

supplied heal, prior to exhausting to Lbe FOD syslem (if applicahle) and stack. The usc ofrol<lry

regeneralive-lype heal exchangers has been applied in European LD SCRs. With this design, lherc will

be leakage helween the untrealed ~nd lrealed gas streams such lhallhe eX;l flue gas has higherNOx

concenlralions lhan lhe LD SCR outlel gas. TIle'direcl-fired flue gas reheat ducl burners will also "r~-~le

No", emissions, which will udd lo the amount emilIe<! Ii'om the boiler and input into lhe I.D SCR ,eaclOL

The LO SCR reaclor, GTG HE, and conneeling ~uClwork will increase lheprcssure drop lhrough rhe nue

gas syslem. This nonnalJy require.., an induced draft fan UPb'f1lde or a boosler fun addition.

MinnkOla Power Coopera';=, Inc. Al·lJ Bum, & McDonnell
!'lOx BACT Annly,;, Siudy APPENDIX AI

Technl""ll'e"ibiliIY Asse"menl Velails for NOx Conlrol Tcchnologio'

TIlt I"dun; IhJt mJke l(lw-dusl SCR leclmology infeasible fOl' Il,e Millon R_ Young; Slation Uni[ J':;

boiler with exi'ting pnrticlIl"le collecliOIl vi;1 c!ce[roslnlic prcclpilnlurs "rC as follows:

• CalalySll'uuJing muJ Deactivation: An exi'ling electrostJtJC rl ecipitalor UpSlre"m ofJ low dusl SCR

reJclor will still expo.,e Ihc "alalyst In 11", acid gn~ conlenl ;md finc p"rlicul"le conl:lining; trJce metal.'

and Ihe l\lgh nJbli mmeral conlcnl of Ihe entrJined IJgmle {]ya,h nollemoy~d by Ihe ESP upSlre"m.

Ahbough Ihe 10lal a,,":mnl uf llyssh canyovcr i"IO the LD_SCR r~-Jclor '" ~""atly reduced compared

wilh a hlglHluSl dc:;]!,,,,. illS Jmioipolctl Ih"llhc low-dllsl SCR cotolysllife will slill be unacoepl,~bJy

'hOrl. TI", small pOrlicle flY".,h passing inlo the reaclor will be suffioien! 10 c<mse pluggagc uf Ihe

ealalysl pures, resulting in dcacllvat;on of the ca,al)'M. TI,e flrillg orJiWlilc coal produ,'c' flne (less

Ih~n 5-~lm diameter) llyash particles, which are alSllltIlSllJkdy 1(> be rcmoved by the exisling

particulate coneclion cXluipmcnt (e.g. ESP) upslre"m of a ]ow-uusl SCR. Thi., erc.les coodition., Ihot

allow lhe.,e ,mall fly",h partIcle., lO enler theporcs o[lbe cJrnlysl, react wilh SO, in Ihe J]ue gas, amJ

furrn sulf"te, wh,ch bind olher ash parlicles inlo a malrix ofsodium-, cakium_, and sullur-rich

moleriJls (likely in a lilTTn of e"kium sulfale). Onee sud a matrix form,; "'ilhin Ihe cal"lysl, il can he

exlremel y lenaciouo ;m<l difficult 10 remOvc. On~ c"laly,1 "emlor's has slaled iIis Iheir uexperience

[h,'l low-tlu'l c"I"ly,1 is mOl e d,ffl",dl [0 clean Ihan that froOl high-dnsl" In. Low-du>l SCR

pcrfurmonce and calalysl life could be severely negalively impacled. Shurtened Ii tespan, of Lbe LO

SCR calalySI will "equlre premalure, extended, Irequenl oul,,);es fur replacement.

• Sile Space COI\<lrninlo; The inslall,lion of" low-III"1 SClt systcm 'vith Due g"s n:heal require, 0

sub,l"nli,,1 amuunt ofspace lor in';lallalion and opelalion. A low-dml SCR syslem wll1hkdy use a

rcg;cncmllvc £"s-Io-gas heal exch"nger (reheaIer) In Iaise Il,e lemporalure of Ibe nue P)-l' "t Ihe SCI{

inlet. A GTG IIE win lmn,fc, heal li'om lhe llue ps al Ihe SCR re"clur outlel 10 Ihe flue ga.' ellte"'n"

Ihe SCR renClor in unb [0 mi,UmJze Ihe supplemenl"l SCll energy usage. Thc l;os-I(I-ga< heal

exchange, diclalcs Ihe foulprillt (If Ihe eold-,ide Jow-uusl SCI{ system_ SI,aee '" required [(Ir lhc GTG

HE "nd fur duclwork in and on! uflbe rehealel. Sulliclenl free space around Ihe reheMtt and SCIt is

al.'o requil ed [or mainlcnonec.

The"",;] around Unil' I and 2 a[ lhe M.R. Young slmion is eXlremely conge.,lcd in Ihe Jrea, wbere

10w_duS! SCR <ySlemo must belocaled. The siluation is particulJrly severe fur Unit No.2.

Equipl11enllhat imp"cls Ihc fe"ihiliIy ofinstolJing J low-dusl SCR sy.'lem un UniLs I a"d 2 includes

Ihe Uuil2 absorbers, lJni12 nue!l"S de,ulfuri7.alion (I'GD) ~cw"lcrin);cquipmenl, ny ash haudlingequipmenl, fuel storage a"d I"msfer equlpmcnl, 'I"eks, fmlS an~ ductwork_ II would l,e eXlremely

DUnl' & McDomlcll Al·34 Milulkollf Power ('O{Jp~ralivc, Ino.
APPENDIX Al

Tcchnical Feasibility Assessment Details for NO" Control Technologies

NO:<. BAC[ Analysis Study

disruptive to the continued economio operation of bolh boiler>; 10 relocate all the memioncd

equipment to Greale space for lhe low-dust SCR systems alllle M.R. Young Stalion. Slades, fans and

duclwork and lhe Unil2 FaD system oannot be readily relocated <Iuc to adjacent structures and the

need 10 conlinue operation whilo constructing the retrofit installalions_ The fuel handling equipment

includes a coal stomge bam and the main conveyors snpplying lignilC to lhe units. Relocating the

coal handling equipment currently occupying >paGe needed for lhe low dusl SCR sys\Cms would be

quite difficult given the site configuration. It is conceivable lhalthc ny ash equipment located west

of Unit I could be relocated to provide some ofthe "pace needed for the low-dust SCR_ However, the

availability of lhis space is doublful, sincc ~voidjng the likelibood ofsevere SCR calalyst sulfutc

fouling will require a new Unit I FGD syslcmto be installed. If a new FGD system is inslalled for

Unit I, lhe FGD syslem wnuld need 10 occupy !.he space thaI can be made available by relocaling ash

handling equipment This space subsequently would nol be avaliable for a low-dusl SCR syslem.

Based upon a teclmioal as~sment lhal looked at lbe various design and Of"''''-tional issues associaled

. c'·, wilh_lhe-instaliation_oflow.=dust.SCR technology_ on_a_Nor:th_D_aJmJ.aJimiJ01Ll<':tS!=e_am-dectric _ - - -----------

gen",ating unit, lhis oontrol option is considered technically infeasible for the Millon R. Young Station

Unit l's bOiler.

A.1.3.4.3 Tail-Gas Selective Catalytic Reduction (LD-SCR)

A tail-gas (TO) SCR is a low_dust SCR system where the LD SCR reactor is installed downstream ofa

FGD scrubber_ The FGD outlet nue gas passes through a gas-to-gas heal exchmigcr (GTO-HE), prior to

passing to the !ail-gas SCR reactor. The nue gas will trnvel through new or modified ductwork kading to

an ammonia injection grid, turning vanes and then into lhe TO SCR reactor_ The TO SCRreaclor, OTG

HE, and connecting duolwork will increase the pressure drop through the nue gas system_ This nonually

requires an induced draft fan upgrade or a booster fan addition.

A schemalio graphic diagram for a low <lust anangement is shown in Figure A.I-6.

Minnkola Power Cooperative, lnc:_ Bums & McDollJlell
NOx BACT IInalysis Study APPENDJXAI

-I echnical Fea>ihill(y Assc>smcnl Deialls fur NOx Conl",1 Technologic,

I<'igure A.1-6 TlIil_Gas SCR ArrJlngemcnt

Low Dust Arrangement

CD Steam generator

® Regenerating heal exchanger

® Air

(~1 F.lectrostalic precipilator

® 502 - Scrubber

® Burner! Heal Exchanger

0' -7.) SCR Reactor

@

- "~~>./,

ti~ l;/"-

I , ....,k~/

~v"

,!lY" ® " -~', 1f"@t,f"y@

® Catalyst

® Vaporizer

@ Ammonia JAir - I\Iixcr

@ Ammonia slOHlge tank

@ Fuel JSte"m

(1Igu," COplecl rrmn wneemOrnior Air I'ollu,""n Control lllefTlrurOJ

The tlue gas Ii-om a wei ron scrubber oulle! c"lering U,e inlet to lhc gaS-\O-g.lS hear cxeh"nger is

expecIcd lo be "e"r lhe ,arurnlion lemperallirc (14 WI') in a cold-side TG SCR applicalion. The

supplemenlal heat addcl! downsIreatn of lhe '['G GTG-HE enn be supplied from high leml'crnlure sleam

coils (indirecl heal exchange) or direelly Ii-om nalurnl g,as_lirccl duel burners_ The flue ga' musl bc healed

10 a minimum ofapproximately 600°F fur the TG SCR NOx- ammonia reaction 10 be effcclive. 'lbe TO

gas-tn-gas heat exchanger is lL'<Cd 10 r""over pnrt of lhat supplied heal, prior 10 exhausling 10 the Slack.

Wilh a rolllry regenerative-lype gas-lo-ga, heat exchanger, lhere will be inlcnlalleakage hClwcen lhe

unlreated and lreated gas Sireams such lhat lhe slnck exilllue gas has higher NOx concentralions lhat! the

Bums & McDonnell IIJ-J6 Minnkola Puwer Cooperotive. Inc.
APPEND1XAI

Technical Feasibility A,,,,,,,men~ Dclail. rOT NOll Conlrol Technologics

NQx BACT Analysi. Slu~y

,

..

TO SCR reactor oullel gas. Using direcl_fired flue gas r~heal duct burners win 3100 creale NOx

emissions, whioh will add to lhe amounl emitted from lhe boiler und inpul into the TO SCR reaclor_

There is limited technic"l information pUblished in English for co"l"fired steam-electric g<:nemling units

(SEUU) wilh 10w-dusilloil-gas SCR !eehnolob'Y in npplicalions requiring full flue gas reheal prior 10 Ihe

r~."elor inleL There is no e>:p~.,-jence with TO SCR on ~;)s Lem hituminon<;, we.,lem ",ubbiluminous coul or

lignite-fired SEOUs in Ihe United Slates. As of 1997, lhere was one low-dusiltail-gas SCR on a 220

MWe Oerman eydOne-fired hoiler with a 1988 retrofit installation_ This boiler W"s reporte<lto he

opcmting wilhout combustion control" Or FGO, burning low sulfur, low ash, moderate moislure

bituminons coal with an avcrage pre-SCR NOx emission role of approximately 1_07 IbfrnmBtu, and wus

mceting :l 30-d"y rolling avemge emission llmit of approxima,ely 0_16 IblmmHm (85% leduction)".

Millon R. Young Station Unit I does not currently incorporate any flue gas desulfuriZ>llion equipment,

which would place thc Te"CIOr catalyst in a low-dust SCR configumtion, which is considered infeasible

when-buming-NOlih-Dakota lignile.-A-new_FOD system for_Unit-l_would be required in ordeLto avoid or. _ _ _ _

signific"ntly reduce expeoled sulfale fOITn"tion within lhe ea~~lyst and g,s-IO-£us hcu! e~ehanger when

combined with ammonia required for the 1'0 SCR_ Unit 2 currently employs a welscrobber which

cllITeLllly treats approximalely 83% of llte total fluc gus flow flOm the boiler. Flue gas rche.t is currently

provided by the FGD bypass (i.e. wann, nntreated flue gas is mixed wilh Ihe cool scrubbed gas)_

The faotors th"l m"ke lail-gas SCll technology infeasihle for bolh Millon R. Young Slation boilers with

existing particulate collection via electlO<talic precipit"tors are as [ollows:

• Catalysl Fouling and Oeaclivution: The TG SCR reactor downstreum ofu flue gas desulfuri•.aliou

(1'00) scrubber will 'Iill be susceplihle to fouling, contaminalion, pluggage, and catalyst

dcactivalion.

o An ~"Xisling cleelro<tatic precipitator (ESP) upstream ofa !ail_gas Sell. reactor will slill expnse

the calalysl to fine particulate contaiuing lrnce metals and lbc high alkali mineral content of the

enllained lignite flyash nol r~"TTIovcd by the ESP upstr~-dm. Allbough lhe IOIllI umounl of ijyash

cmryover inlU lhe TG-Sell reaclor is grcatly reduced compurcd with a high-dust d",ign, il is

anticipated thai U,e tail-gas SCR catalysllife will slill be unacceptably short.

o The firing of lignite coal produccs fine (less than 5-jlm l1i"meter) flyash partieles, which are also

least likely 10 be removed by the oxi,ting particulate collection equipment (e_g_ ESP) upstTc"m of

Minnkolll Powel Coopcmti"e, Illc. AI_37 Bums & McDonnell
NOx nACT An,lySlS Srudy APPENDIX Al

Tochnical FeasibililY Asses.,menl Delails for NUx Control Technologies

a TG"SCR. Hue ga" with entrained line paniculale mOiler, includil\g ,OmC involving wdium and

,ulfm-conlaining coml,ou"ds, will pass lhrough and be carricd-ovc, from a well'GD scrubbcr.

This IrC<Llcd gas ,tream w1l1 carry sodium s\llfn1c p~rlicIcs, formed by 110mogL'TlOtl' coll(\ensnlion

afler exiting llle bOller Hnd nol removed hy the ['UO syf<1em. into lhe calalySI ];,y~rs of the n,-

SCR r~uclor. A dry FGD syslem followed by" f"bric Iill"r "pSlre"m of Ihe TU-SCR will slill

allow sulfur-beoring nuc g'" ,md fine pan,cles 10 enler the calalysL There is 'LTIO"S concern thaI

fi"e p'rlic1cs P"S>lllg inlo lbe reaelor will "ee"mul.k within the eOI~]Yol, m,d be ,e.,isl",,1 10

rem(}V"1 by "onvenl,onal 300thlowc,-,; "nd olh"r ckming leclmolog:i",. Thi, crealc~ comhlions

th"l allow Ihese ,man nyosh p"rlicles 10 enler lhe pore, oflile calalyst, ,eact wilh SO, and/or SO,

iulile Hue WlS, 'nd fonn ~ulfatcs which bind other ash parlicle, iL1IO a malrix ofwdium-,

calcium., 'Inri ,ulfur-rich malcrial, (l,kely in a fom, ofcalcium .,ul rote). Once ,uch a mal""

fonn" wilbin Ihe calalysl, it en" he cXlTcmdy Icnaciou' ami diflicuillo remove. C"I,dysl lhal is

cxpo",·d 10 such condilion~ w,ll bc incfleclive almamlaimng aueqllale aClivily upon whIch lhe

performance orlhe TG-SCR's NOx removal i, based.

o TI,e,e enlraincd purlicles will also del'o:;; On Ihc fI,S-lo-.I;a, hear exchong:cr "head 01" 11 te lolil .1;"'

SCR r~""clor. Th'," ueposlllOn wiII (1CLT""'C hcal Imn,fcr belwcen lhc mcoming (cool) flue ga,

",,,I lhe oUlgoing (wa, m) Ilue gu,. Soolblowers could be used 10 remove the accumulated

depos,ts from lhe GTG HE, bul the SCR reaclor could 'till 8uJl"cr calalyst fouling fmm lhe

deposic, dislodgcd from Ibc UTe; II E cleoni",; eycle becoming r"""lmincd in Ihe reh~,lt(1 n",:

ga.,. T~il-:;J' SCll pcrforTnance ami e"I"ly"1 l;fc co"I,1 be sevcrdy negalively impacled.

Shorlened life,pan3 01" lhe TG SCll calaIY31 w,ll require p' em.lure, eXlended, frequenl oUlages

for replacement

• S,te Space ConSlrainls; Th~ in"lallalion 01" n 1:lil"g~s SCR sy:>le", willi nIle gas reheat ,equirc~"

subst,"lial ~rno\lnl ofspace for in,tallallUn "nd opcmlion. A tml-lWs SCR "y'lem wi1l1ikcly use a

rq~l"IIcmlivc gas-to-gas heal exch'nge, (rchealer) 10 mise the lempcralure of lhe Iluc g"' at Ihe SCR

inlet. A GfG lll'. will Irnmfcr ru:"l from the Huc gas a1 Ihe TG SCR reaoloroulJel lo the senlbocd

Iluc gas c'Tllcring the SCll r"ador in oakr 10 minimize lbe snppkmL"rlI"1 scn energy usage. The ga3-

lo-g"" hea~ ~x"h"n~cr diclales the roolprint oflhe TG SCIl sysl"rn. Space is requircd for the on;

lIE and for dUOlwork in oml uul uf the ,cheater. SujT,~i~,,1 fr~c spaee amunulhe ,eheatcr und SCR

8ystem is also required for maintenancc.

The area around Uml, I and 2 "l!hc MJt. Youog: "'.l,on 'S eXlremely eoogcsled in th~ aT~-clS where

TG sell 'y31em, musl b~ localed. A Hue gil" uesulfunZilliOJ1 syslcm will be neede<J for Unit I in lhe

n,,,", & McD<lnndl Al_3~ MinnkOla PowcrCool'emtive, Inc.
APPENDIX AI

Technical Fea,ibility A",essmeOl Details for NOK Control Tccllllologie,

NOxDACf Analysi, Study

near future 10 comply wilh lhe Consenl Decree. When a new FGD system is installed forUnill, lhe

FGD system wouid need to occupy !he space lhat can be made avallable by relocating ash handiing

equipment_ This space subsequenlly wonld nol be available for" tail-gas SCR system_ 'mus, the

availabihty ofadequale space for all lhcnew FGD and TG-SCR system equipment and structures

while accommodating exls~ng coal slorage and handling needs for both exisling boilers at Mihon R.

Young Station is doubtfuL

The challenges for installalion of nCW ductwork, SCR reaclOrs, and fluc gas rehealing equlprnent and lhe

lack ofpertinent experience with all aspcclS ofdesign. construction, operation and mainlenance oflai1-1}"

SCRs on such high_fouling coals as North Dakota lignile are significant. The flue gas oondilions thallhe

TG-SCR oatalyst will be exposed 10 will crealC unresolvable fouling and blinding !hat makes successful

applicalion of this technology diffioull, expensive, and uncertain.

The risk offailure and uncertainty ofsuoccssfully applying Jow-dust, tail-gas SCR teohnology to a

---::_'- cyclone-fired utilIty powerplant-firing-North-Ddkota-lignitc appear_subst=tiaL

Based upon a technical assessment thai looked at lhe various design and opcrational issues associated

with lhe inslallation oftail-gas SCR technology On a North Dakota lignite-fIred steam-electric generating

unil including a cyclone boiler. this control option is considered lechnically infeasible for the MillonlL

Young Station Unit l's boiler.

A.1.3.5 Electro-CatalytIc Oxidation (ECO~

Powerspan's Electro-Catalytic Oxidation (ECO"') syslem is a mnlti-pollntant technology designed 10

control emissions ofNOx, So,,/ine particoble, mercury and certain Hazardous Air Pollutants (HAPs).

The Eoo'" process has two main process vessels, a barrier discbarge reactor, and a multi-level weI

scrubber. Thc barrier discharge reaclor ntilizcs an electrical disoharge to create oxygen and hydroxidc

radicals ""hich lhen react with NOx, and other eonstituents in the flue gas stream. The flue gas stream

lhen enters lhe bollom ofthe ECO'" scrubber where the lower loop eools the flue gas and reOlov,," a

portion ofthe acid gasses [sulfur trioxide (SO,), sulfuric acid (H,SO,), nitric acid (HNO,)] produced in

the bamerre.clor and oxidi7rd metals snch as mercury, with a low pH aqueons arrunonia reagent A

second sCt1lbbing loop is then entered where addilional SO" NO" acid gases and oxidized metal" are

removed wilh an aqueons ammonia reagenl. though at a higher-pH_ Above the second scrubber loop is an

absorber seotion for absorbing fugitivc ammonia from thc first and second SCt1lbbing loops. The fmal

Minnkola Power Cooperative, Inc. AI_39 Bums & McDonneU
NO, BACl Aoaly,i., S'udy APPENlJIX A]

Technical Fe"slbili'y Assessmetll Delalls fur NO, ('oulro] Technol"gie<

Slep io the EC'U'" proceS" is a wet declJaslatic precipilator (WESP) which collecl" fine (XI11ieuiaie maller,

aerosols generaIed in Ihe serubbc~ "nd "ddilional mercury. An updated sebematic rroc~ss flow diog, am

fur Ihe ba5ie EC'U'" pmccss i, shown in Figme A.I-7.

Figure A.1-7 - Electro-Catalytic Oxidation (ECO®) Process Flow Diagram

Ico!'I"I [rom hnD:!/"""''', 'I"'.goy/.oped"",,_w/"p.'l>IEPA611111WJj 1O_]1!ID

ECO" Process flow

!: ""~'!'"'Jm ",. Hr,,,,,"...~--"-· 10",·, 'H..-

£00 R,a,lIJ,

Ablllb" v",,,,,]

W,I fliP

r..-l'roiDa 8",,1I'''Y i " ,J

., -,

.~

.rcl

Puwerspan has been involved in an extended HC[J~ proc","s demon.,tralion ~"ing a 28 MW Commercial

Demomlmtion Unil(CDU) al R.E. Burger »lallon Unils 4&5. The ECO'" COU projecI lr~alcd a

slipslream and demonstraled r~rrormance_ reliability and economics for apprOximately On~ year. Thc

demonSlrnlion progmm slMCd in January, 2004. NO" removal is Slalcd 10 be up [0 90% w,lh u claimed

0.05 lb NOx1mm Iltu oull.t condilion achievable for lh~ fronl--end or lhe ECO'" process. Further ,uslained

op"mlional le,;1s orlhe ECO" COU are unMrway during lhe second and third qnancrs 0[2005.

As this i, a posI-eombuslion mulli-pollutanl controllechnology, il is elaimc<.llhat lhere is little S~"T1sili,'ity

to Ihe lype boiler or bnrner>< lhat Powe"pan'. Eloctro-Catnlytie OXiu"lion (ECO") process cun be

Bums & McDonnell AI-40 MinnkQla Power Cuorermiye, Int'.
APPENDIX Al

Technical Fca,ib~i,y A.,c.smcnt neroil. for NOx Control Teclmologie,

NOx BACT Analysi. Study

polelllio ny applied to in order loreduee No" emissions. The effectiveness o[lhis ECO"'process for NOx

control has bc'Cn dernonslmlcd on a sliIKlream commcTcial demonstration unit (CDU) assooiatoo wilh

pulvcrized fuel hoilers firing midweslern or eastern biluminous coal.

J'owcrspan'8 published dUIll from Ihe commercial dcmonstralion uni('8 performanoe ofup to 90% when

treating flue b"'S with an inlet NOx concCnlnllion around 0.5 Ib/mmBtu. Thi, wouldrcsult in" slaok NO:.

emission around 0.05 Ib/mmBtu.

The ECO'" process ha' not been demOnSlrJlc<1 in a full-scale configumtion on anyunil, nor Icstcd in a

slipstream configura lion on any boiler that lires western subbilUmjnous coals or North Dakota lignite. II

has al80 not been applied to emissions from a cyclone-fired boilcr. Accordinll111e EPA's Drnfi NSR

Manual, "Technologies which have not been applied to (or permiUcd for) full scalc opcnnion, need nol be

considered ;,vailable: an applicant should be able 10 purchuse Or construct a process or conlrol device Ihal

has already bc~-n demonstraled in pTaelice".

There arc Dnumber ofissues wiih firing North D"kota lignite lhat make Ihe applicability of the ECO'"

proc,,",s lechn icany infcasible for MRY Sialion boiler;;_ These issue, include:

• Deposils und Pluggage: Tne Dyash dcpusition charaoleri,tics of Ihc North Dakola lignile arC

cxtremely severc. Anything Ihat contribulcs 10 nyash depo,ition and pluggage within Ihe barricr

rcuclOr i.' expecled 10 havc a detrimental impu"l On the mulli-pollntanl control p"r[ormanoe of the

ECO"'proec.s, and Ihns coul,l havc u serioll.' impacl on MRY Stution opernlions. Thc luck of

demonslnncd opernlion on trealing lbe emissions from a boiler firing coal wilh a high slagging

index precludcs Ihc use ol"the ECO"'proocss as technically feasible for BACT as applied lo"

boiler firing Norrh Dakota lignilC.

• Reliability und Availabilily: Millon R. YOUng Sialion's major planned oUlllges l"or each 'mil f\rC

schcduled 10 occur OnCe every three y""rs. AnyNOx oonlrollechnology sckelcd as BAC'T will

need 10 operate year-round, ycnr in Dnd year oul, on a routine basis, while performing at high

Icvels ofpoHutanl rcduclion. The Powerspan ECO'" 'yslem is a new technology and is nol as

highly developed us olhcr mOre common NO" and SO, oontrollechnologies such as SCR or

SNCR plus WCl Or semi-dry flne gas dcsulfuri7.lllion (FGD). II is e~pc"I~-d 10 require a full-limc,

full-scale application with sustained conlinuous operation 10 confirm levels ofcmrc"Iltly

dcmon,l",led reliabilily and Dvuilabil ity from Ihe ECd" CDU arc acceptable lo meet !hc

Minnko'. PowerCoopem,ivc, Inc. A1-4l DUITlS & McDonnell
NOx DACr Analysis Slody APPEN0IXAI

Toehnie"1 FOa<ibiliry M,e"menl De",il, fOT NOx Cnno-ol TedUlalogies

expeclalian of infrequent major OUl"gc" ovcr lang time periods while maintaining high level, of

controL

TIlLTC aTe addilium,1 faclun; lhal m~ke the apph"," lion of lhc ECO" procc" pol~'Tllially more difficolt lhan

othel' eSI"blJshcd emission conlrollechnologies available fol' coal-Jired pnwel'planlo;

• TI,ere " a Jack of experience wilh lhc ECO" dowmtream ammonia .,crub\>er'" coproduol

cry"lalhzalion and gr.lnuli~alion equipmenl de.,ign, ope,-a'ion, 'Illd m"inlcnance, which was not

included Wilh lk inili,,1 commercial demon,lmlion lInil. The coproduci slream lh,,1 would

'w, mally [<:<:<1 inlo Ihc cry"lallizalion und gnmulalioll processes was colle<ole<1 "nd tran.<[lOfled

ofrsilO fOT lhi, process step during COU operalion. Because c,ystallJzalion uml granulalion of

ammonium sulble from an ammonia scmbber solUllOn i, l\ol a new lcchnological proce"" lhis

was nol cOllSJdered a ledmic.1 feasibility deliciency. For inSlanee, the D"kota Ga,i Iic"lion

Company (DGC) in BeuJ"h, NO cun'el\tly 0pcl1ll<:s an SO, scrubbcT ulilizing 3<hmonia as a

,eageoL Following- Ihc g-eocralion of ummonium sulfa Ie, OGC crystallize" and b'TIlnulale~ a

f"lili",r prodllCt Oll Hite. IIowcvcr, al MRY ,stalion, conHiderahle COSl$ would be ",currcd [or

mlenm 'lorage and shipmenl ofIhe ECO'" proee", ,cwbbcr's l"IUid blccdslream unlll sufficient

expe, ;cnce has "lenli licd ,,"d eliminme(l polcnlial failurcs "nd repain; for lhe cry"I"Jlizalion aod

granulal,on c'llPipmcnl should lll'roV<" 10 be unreliable.

• Siz{' of lbe ban iel' reaotor: Puwcn;pan recenlly JlldicOlCd lhOi Ihey would sc"le the r<--Jetor far

optimum cO,l and Sf'''cc "mlllgemenl hased upon k""uns lc.lrned from the enu p!<onloperal;on.

The tlllUlbor u[ incliviclu"l pa""f(es wilhm a bmTier Teac[or sized for eilher of MKY ,slalion

bOller"' maximulll flue gas llow und ~as Blream coosliruenL\ is cxpe<oled In reqmre a Oro,,-

,c",lion,,1 'lTea oom[lat ahle l(I h"lf ofa large eleClrOMnliC prccip'I"IOr. Allhough ,Ilis I"" nol been

closely ""amincd for "II .,peels ofdcsign, con,lrucliun, operalion and main[(;n~nce, lhe amounl

of physic"l "pace required to hold lhc barrier reactOl' and inlet and oullel ductwork is belicved 10

nOl be uvmJabJc for polential I'elTOfil 10 MRY ,slation un; L'_ ,s ile 'pace eon"trainls arc comidered

l(I be a barrier 10 lc'Chnic"1 [ea.,ibiIJry for pOlenlial applicalion o[ the ITO'" process at Millun K.

Young Sialion [or Unit I and Unil 2"s boilers_

• AddillOnal sLal,on auxili~ry power consumplion; The bmrier reactor, pilL< lhe "rnrnonia ~erubbcr

und wei e1eclro"I"lic prccipilalllL' addilions by an ECO"" "Ys1cm, reqUITe an increase in s[allOn

flu",.' '" McDnnncli AI-42 M',nko(a P",,"'CrCaoptmliYo, Ino.
APPENDIX Al

Teehnical Fea,ibilily A,,,,,,,menl Delails fnr NO>< Control Tcclmologies

NOx BAC[ Analysi, Smdy

auxiliJry power consumption. For NOx comml, !his includcs more horsepower required by the

hoosier fan nccded 10 compensate for !he flue g35 pressure drop crcatcd aoross lhe barrier renelOr.

It also includes lhe power consumed by the dCGtrodes of the hJrricr reaclm ilself.

BecJuse of thc lc"hnicai feasibility issues Jnd lack of commeroial availability and full-scale experience,

e,]>CciaJJy on ..uoh high fouling coals, rhe flCO" 'yslem WJS considered lechnieally infcJsible JS a BACr

ailemative for M,llOn R. YOUllg Slation for Unit 1's boiler_

',,-. A.1.4 "Layered" NOx Reduction Technologies

Many ofthe NOx emission reduelion leehnologies which involve fumace or conveotion pass arcas for

lheir introduction inlo lhe nue gas stream have beeu, or can polentially be, applied in combinations so as

lo rcSUll in an overall higher lcvel ofremoval. Separaled overfire air, various types offud reburn, and

various forms of SNCR could pUl<:nlially be combined io series 10 rcduoe NOx emissions prior 10 boiler's

nue gos cxil. However, all the possible NOx conlrol1echnology combinations have nol been installed 00

,,~. coal-fired pow~-rplanlS, SO actual feasibility of"orne combinations have not been demonstrated as viable,

.. parlioularly in considelillion of lhe special challenges posed by cyclone boilers firing lignite coal.

A.1.4.1 SOFA Combined With Other NOx Reduction Technologies

Separaleu Overfire Air can be favorably oombined wilh every othe, method in order 10 reduoe lhe amounl

ofreagenl or reburn fuel required to achieve lhe resulring level ofNOx emission reduction. Some oonLrol

lechnologies, e'1'Ccial1y eonvenlional fuel reburn syslcms, require overnre air to complele Ihe combuslion

oflhe Slaged fuel admilled lo lhe upper fUnlJce. Fuel lean gas rebum can be applied wilh or wilhout

SOFA. as lhi, limiled JmOllnt ofSlaged fuel," inlroduced inlo an oxygen_rich almosphere down31ream of

lhe cycione burne,,; and any overfirc Jir injection points.

A.1.4.1.1 SOFA with SNCR

Seleclive non calJlylic reduclion lechnologies are post-combuslion, in-furnace NO, control allemative"

lhal have bcen inslalled in numerous boilers of various dCj)igns, fuel types. wilh and wilhout overfirc air.

n is usually advJntageous to ~pply overfire air so lhal lhe amounl of ohemical reagenl consumption can

be minimizod iu order 10 achieve the largctcd NOx emission rate from the boiler o"llel.

Minnkola Power Co'l'cr.lli".. Inc. Al-43 Bums & McDonnell
NOx BACr ATIalysis 5mdy APPeNDIX Al

Ted"'ic"l Fea,ibilily A.~,c..,menl Dol.il, [or NOx Conlrol Tedmologic.,-

Tesl< nl Cunttliv's B.L Engl"nd Slation (Units I and 1) demunslrJICd IhM SNCR C'n de~TCase NOx

emissions as nmch as 31% al full load, from 0.55 10 0.]8 lblmnilltu, over and above Ihc reduolion

possible from owrfirc air alone (approximaloly 60"10 drop, from 1.3 to 1.4 down 10 0.55) in full OplTILlion.

Til,s LS an overall NOx orni"ion n:r1Lrcllon of72% riom pre.rolrolil haseline".

SNell can be applied alone nr oombined w,lh cithe, the ba"io or Ihe advanoed rot"", ol".,ep"rJled overli,o

a" (ASOT'A) On MRY Siuliun bollcrs. An-,taging Iho cydono wilh Ih~ m" oh'1'"n'lcd ovedi,e air 10

furthn c0ll1pkm~"1I1 combuslion NOx reduolion is "n oplional pm1 of this lechnique, However,"S

prcviou"ly explained in the di"oussioJl of SOFA "liemalive".this will ri"k slag "freezing" ,n Ihe barrel.'

and lower furnaee. E"limaled NOx ~mission rales for using SNCR lechniques wid, N<lrlh Dakota hgmlc

eo""idercd l'uhli,he<ll~vel~.chl~ved by cyclone-fired UlliL' firinC weslem ,ubbiluminou, coal, and

vendor estimatc". SNClt wilh ASOFA is expecl<:d 10 rcducc NOx emissions "pproxim"tely 31 % below

NOx levels predicled lor ASOI'A operation, and polenlially 5~% overall from current baselinc level for

lhe MRY Slation Unit 1 boiler wilh Ommun", ,lip limited to approximately 5 ppmvd. Tl\i~ h,ghe"t

performing ba>Je SNCR sy"l<:m is polen(ially able 10 ath[cv~ a NOx emission rale of0.355 lb/mmB(u,

whe"1l cumbined I"ilh lhc "dvanced [onn of~OI'A On MRY Stolion Unils I ooiler dLiring- operalion"t the

pre--control bascline (near MeR load). Thcse I~\'cls ofNOx reduclion depend on rhe advanee'd [onn of

,epm aled o"erfire air lechnique 10 achieve Ihe expecled NOx ,educl,on percentage" when .ppl,ed 10

lignile-lired cyelone hOllers.

Anolher foml ofSNCR i, combmed with ,epnrJled overfire air. TIli" is eurrenlly being marketed

commerclally as '·Rotating Mixing" (RoLam'I<), In lhe Uniled Stale"' ut'l ilies mduSIry, Ihis has only heen

upplled 10 l'ulvel'i7ed 0031-1),cd bOllers. h 's rlifferenL lhall b~sie SNCR ill Ihal il ",eludes (> hoI ai, housler

fan and II ,mnll 3mb,enl "ir non, "nJ injeels the ammonia (or urea) re"genl inlo lhe hi[\h-pres"urc uverfire

air flow ,Iream "hcad oflhe R01<A nozzle,' oUllel.l. This mixlure i, imp"rtetl inlo Ihe bOller m lin offset

fashion [rom opp",ile side' of the jil",no~ "t hig-h velocilJe", with muhi-pmt nozzles locnl<'d al hlgh

c1cvnlions relali~c 10 Ihc lOp burncr row. This vendor (Mobolce USA) oluim:; Ih"l Roillmix (rolalinl;

opposcd fire 3ir Or ROFA + SNCR) help, lo di"lrihul<: Ihc rc"l;cnl ""rO", lhe furn,,"c cruss seclion, which

max;nl;zes in-[umaee NOx reduction whilc minimizing negative lmpacl" OJ] earbon monoxide and 11},,~h

unburncd cnr!JOll. Thre~ l"nl;c"1IllllIly-fired ulility hOl krs burning easlern bilumlllous eoal or Illinois

biluminous co.1 WC,e relrofilte-J wilb Rotamix, each achicving a NOx rcdllClion of approxi"'"ldy zero 10

55 pe,cent beyund the levels produced by ROFA "lone, from l"e.SNCR haseline.' ,,1'0.2110 0.2~

Ib/mn,Btu d01Nl1 to 0_10 10 0.23 Ih/mm'B(u wi Ihoutlow-NOx hurner,',"·",,....

Bum' & McDollndl Al--'l4 Minnkola Powor CAoperdll~c, Inc,
APPENDlXAI

Teelmical Fcasibilily A=smeUl Delail, for NOll Conlrol Teclmologies

No"nACT Analysi, Study

While lhis vmiJtion ofSNCR combined with separated overfire air could pol~"!llially be ~pp1icable 10

cyclone boilers, il has not been marketed 10 ,erve .,uch applicalions. Sinec cyclone boilers do nol require

Ihe addilion of hoi air boostcr fans for SOFA, .nu oplimom injection localions for bolh SOFA and SNCR

reagefi' may nol coincide, ROlamix may nOl perform as well as, or sib'TlIfieantly better lhan, a wdldesigned combinalion ofconvcntion"l SOFA and SNCR. This technique is nOl dislincl enough rrom

basic SNCR rrom fimclional and air-slaged cyclone NO" reduction pcrrol1rumce sLandpoinls to warranl

imlividual consideration for MiHon R. Young Slalion boilers. Because ofa lack of cyclone-fired boiler

e"perience wilh ROFA amI Rotami}[, the !DLter was considered inreasibJe and thus was not included in lhc

control effeclivene.ss and <:<lSI-elTecliven"", seclions of lhe main r"-porl.

A.1.4.1.2 SOFA with RRI

Rich Reagenl Injection must be used in an o"ygen-deprived atmosphere in order 10 effectively reduce

nitrogen nxide emis..,ion,. This requires air-slaged cyclones and scpijrJted ovcrlire air operalion.

The NO" c"111ission rcduelion rcag""l injeclion for RRI processes must be precisely lo,,"tcd and carefully

controlled 10 be effcclive. Opcrolion outside of lhe required opc"TIlling ranges can even result in inerc2,cd

NO, emissions. E"lensive computational J1uld dymlmic (CFD) simulalions are needed 10 determinc lhe

oplimum injeclion poinls_ Boiler operating conditions will change wilh unit load and varying fuel

charactcrislies. The RRI process COtllro] syslem., mUSI be able '0 adjusl for thcse chunging condllions.

RRI has thc pulc"IltiaJ 10 provide a modcrulc degree ofNO" reduction on coal-fired boilers_ D'H~ from

B.L. England and Siou" p1anl, show Ihis ledmology can reduce NOx cmls,ions belween Zero and 39

perccnl beyond !he amounl atlrihu!able 10 overfire air syslem operalion"~·~5~""7. During inilial

demonstration l",ling ofRRI al Amerco's Sioux Uni, 1 boiler, 500 MW unil firing a blend ofPRB and

midweslem biluminous coals (withoul SNCR), wilh SOFA in AuguSl2001 al a lower furnace SR of

,ppro}[imateIy 0.99, NO" emissions were reduced appro"imately 55% 10 0.551blmmBlu wi SOFA only,

with Z<.TO 10 15% additional NOx reduclion hum ,RRI (down to 0-47 IbJmmBlu) with zo,o ammonia Slip".

Results of lhis inilial RRI lesling ul Siou}[ plant wen: poor at cyclone sloichiomelri~ ratios c100c 10 0.99

bcc.use inoonsislent, sporadic, and non-repealable NOx emissions reduclions between zero and 15% were

measured. Subsequent RRJ testing al Sioux Unil I in March 2002 wiill SOFA al an average cyclone

stoichiometric rntio around 0.95 showed NO" emissions reduction of29 pcrcenl (down 10 0.27 lblmmBlu)

beyond those achieved wiill a modest amount ofcyc1one air-Slaging wilh SOFA (68% drop down 10 0.38

IblmrnBlu from SOFA alone), for an 80% overall dccrca'e from unconlrolled baseline; RRI CFD model

MlnnkolO Power Cooperative, Inc. Bums & MoDonndt
NOx BACT Aualysls Sludy APPI.:NDIXAI

Tedwical Fo"ibilily AS5essmenl Del.il, for NOx ('.<mtrol Technologic",

prediclions for Ihese conditions were NO, emIssions reduction of., 1% wllh Hill. and 37% withoUl FGR

operalion. Tooled NO>; emissions wilh RRJ+SOl'A in 2002 wcre wilh a reagenl nOl'mali7"d

sloichiol1le~·,c ralio (NSR) of] (II" Nil, per Ih NOx)".

Parnmelric te'ling al Sioux IiniI I in May 200S I'eduoed NOx emlssions belween IS-38% wilh RRl, down

10 O.IS to 0.20 Ib/mmBlu. Rcagl"1l1 NSR bclwceo 1.0 and 4.0 and low ammOl1," slip levels kss Ihan 2

ppm from an e,lahli,bed ha,eline conditIon of0.20 to o.ns 1l)/rm"lJlu level achieved NO, emissions as

low", 0.12 lbhnmBlU wilh deep oyclone ail'_Slaging and SOFA opc""lion rLring;m 80:20 PRBllilinoi,

coal blend "I 480 MWg unil OUlpul".

n,e imem oflhe lUU process lor NOx reduction is lhal il must he ",ed in conjunction with air-"IUTV""

(Subsloi~hlOmelrie slflged_air) cyclone eombustmn re,ulling from Ihc m,IflHallOn and operalion of all

OFA SySll"Tll, wilh ur wilhuul SNCR. The cyclone"' air/fuel sloichiomclry m\J'1 be carefully controlled to

lll"inrnin fuel-rich ",,",Iilion, for lhc lUU process 10 be effecIive. The oombllslion g""" in lhe vIcinity of

lhe RRI urea mjeclion porls mus[ be essenllally devoid of f,ee oxygen, in order 10 aVOId oxidiziLl~ Ihe

ni"of:en eootained in Ihe injeoted Ieagent, which will iocrca~e NOx 0",i,,,i01l.'. 1'0.-1 ignile-til'ed cyclone

boilers, lhc b""o form of:;L1'""le<1 UVl.,-li", ;IIr (wilhuut ",loealeJ hgnilc drymg ,y,lcm wnl ports) is

ll1compalibJe wilh RlU. Rc"gcnl injc"Clion will be neor the eleva,ion oj" Ihc cxisling h~ile drying 'yslcm

venl ports in (he lower Irolll "nd TC"r ,,,,,lIs of a lib'lllie-fjred cydone hoiler located immedialely ahove the

lOp nlW.' of cyclone"_ n,e oxygen iolroduoed wilh Ihe lignile drying ~y'lellL·., vented moi.'llll"e_ladm

airstreams will eausc Ihe ureu 10 he o~idlZCd, eroating NOx emissions.

The advanced Imm of SOFA rcloc"les (hese Ji~'Ilite drying sy,lem veLlt ports from Ihe lower 10 the ",i,ldk

rumace, enhancing lhe desired in-fumace niIl'ogen oxides reduclion proco" Therdore, io order fur /Uti

10 be l'~en model aldy eHecuve in l'educJng NOx emi."ion~ from a ji,,'IliLe-firt<] oydone hoiler, Ih,S

lechnolo~'Y mu,l be ~umbined wilh an ulj,,"neeu Imm of,cparalcd oVL"Tlirc "ir, whelhc.,- insl"lleu with Or

Wilhoul,sNCR.

A, menllunellin the [easiIJihly discu"ion of "pplying ",paraleu uvcrfil'c air 10 lignile-li",(\ cyclone

boilers, lhe degree 10 which each "nd every individual cyclone fUn\ace can he suocessfully opor~ted wiill

Ie" lhun lheorelic"l (.,uh"loiohiomeIt'io) wmlmslion uil' direcily imp"clS pOlenlia] NOx ("orrMlion and

further in-Ium"ec emi"i"n rc<1uclion. Bc-causc lhe heat conlenl of lignile Irom lhe Cenler mine i~ not

Bnm, &. McDolJIlell AI·46
APPENDlXAl

Tcobnieal Feasibility As'CSSIIlOllI De",il. for NO:>: ConlrOl Technologies

NO:>: BAC]' Analysis Study

consistent from hour to hour, there can be subslantial deviations in air/fuel mtios for individual cyclones

from the overall aVeI1lge.

In the case ofMRY Station boilen;, Minnkota. has simultaneously sompled lbe unprepared lignite reed to

seveml cyclones' lignite drying syslcm, in order 1.0 determine the variability in the cornbuslible and asb

components ofNorth Dakow lignite. Thi. invesLigatiOll found that fuel quality varia lions <:an resull in

individual samples' healing values to ha ~e a maximum differential ofover 12% oflhc lignile samples'

average.

TABLE A1·1 - LigniLe Heating Values and Variations for

Milton R. Young Station (Unit 2)

M.R. Yonng Slalion OJ rrerenoes Betwc...."TI lndividual

Individual Cyclone Lignite Samples CyclOlle Li~nile Samples

Higher Heating Value•• }'erOCnl"ge of HHV Differential, PCTCentage of

BlUllb Average l-111V BruIl" Avernge BUV

Minimum HHV: 5,852 88.9% Minimum: 4 0.06%

M"ximumH1-1V: 7,101 l-ffl% IIJ"(',~ Maximum, 797 12.1%

-- Averagc HHV: 6,584 100% Average: '" 2.51%

'Vben operating with air,slaged oonditions a,.,,;ociated Wilh separated overfire air, any individual cyclone

wilh li!,'lIiLe heat inpul lower than ~ver~ge can anow significanl amounlS ofoxygen 10 o"idi.", the urca

reagent ~t high temperatnres, thns increasing NOx emissions in lhat zone at lhal lime. Cyclones with

lignile heat inputs higher than average would produce lower stoiohiometric airlfuel rntios and less NO"

emissions. Less oomp1cte combUSTion in the deeply stuged cyclonc, may release imrnfficienl amounls or

heul. Ihus rai"ing the risk ofsolidifying the fuel ash so lhat it accumulates within the cyclone barrel. This

could resull in Dring auxiliary fuel oil or laking- the boiler oUl-of."ervioe to remove the plugg-age. Neilher

of lhe.,e wndiliOlls is desi",ble because they resull in increased cmiosions, lower performance, and higher

operating costs_

The MRY Station Unit·i boiler's cyclone air/fuel mtios vary in TCal"!ime based on significant changes in

combustible contenl on an individual cyclone by cyclone basis_ Adjnstment of individual cyclone

wmbustion air inpuls to eompem.ate for the variability in indiVidual cyclone lignile heat inpul rates for

Unit 1's boiler would be necessary 10 maintain con,islc']]! substoiehiomclric operalion orevery cyclone

during air-swged eombusliOll. This pluces g-re~t emphasis 011 achieving lighl wnlrol over Ihe air/fuel

Minnkom Power Cooperallvc, Inc. AI·47 I1ums & McDonnell
NOx flACr Analy'i' SluJy APPENDIX Al

Technical Ft·.sibilily A,,",ssmenl [)e",il, [m NOx Comrol Technologic,

rallo, on each cyclone dw-ing air-staged tOmbuslion opCI1lli"n in order for ASOl'A 10 be succe",lul in

producing sib'llificanl oJdilion.l NO" emissions reduction on lignlle-lired cyclone boilers_

There IS "0 equipmenl available for coaHi,ed boilers lh~1 CO" measure the fucl heal inpul al the prepared

feed injeclion poml on s\Jch a variable fuel 10 allow Ibe delelminallon of r"".<onahly accur~lc ulr/fucl

r.lios on individual cyclone., m reallnnt. Wilhoul being "bie 10 me",ure the cyclone ,ir and heal inpuI,

to allow for conlrol or air/Iud proporlions "m] emisSIons, the ,toichiometric rallo" 0(· individual cycloncs

oa" nOl be ostnblishcd "cellrJlely to produce combuslion producl$ e.<senllally devoid of [rcc ""ygen. Thi.'

requirement i, e'l'cei"Hy necessary when employing RRllO avoid merc"sing, r"lher limn reducing, NOx

clmssions onlhe Millon R. Young Stalinn Unit 1 bOller.

Beoouse or Ihe sJgnific.nl insurmountable problems discussed ahove which would incroasc NO" emission

rulc" RRI lS con,i,k,,<1 Icehnieally infeasihle for applicatioJ\ nn lho Unil J oyclone buikr allho MIllon R_

YuungSt,lion.

A.1.4.1.3 SOFA with RRI and SNCR

When RRI lS comhined wilh scpnralc<1 ovcr["e air a11d SNCll, il h"s demonstrate.:! very lIigh NO~

emi"'om reduclioll al Conttliv's RL. hngland Unil 1 boiler during ,Illlrl-lerm le.'ling firing cuslom

bitllminllu, ~o"l, on the ordn 0180% from an uncontrolled hoselme oTolmd 1.2 lblmmBtu". In May

2005, lesling RJU+SNCR+SOI'A at Amercn's Sioux Unil I boiler finng a high J'Rn-blend coal

demonstraled NOx emisswllS a" low"., 0. 12 lh/mmRlu. This was from an eslablished baseline cnndilion

or0.20 Ib/mmlllu level aohiovcd wilh 'kep cyclone "ir-staglng and SO!'A nperalion. Tho,e le'ling

",ulls wh~." firmg on ~O%;20% ]'JW/JIliLlOi., enal hlend ol 480 MWg ,mil oulpul wilh " rcagenl NSR 0 [ 4

"nd ammonia ,lip limited lu less than 5 l'pmvd, .,howed an 'w",dI90% reduclion wilh no apparem

adverse short-Ienn impacls ofdeeper alr-SLat",1 combuslion logelher with overfire air, RRI and SNCR

,. - " app lc"llOnS .

Became ofthc "ib'llificanl insurmounlohle problcms rtgurding RlU"S menlioncd above, RRI wilh SNCR

~md ASOFA i' considcred lechnieally infeasible for application on lho Ullil I eydone boiler "I the Millnn

R. Yo"ng Sialion ,lue 10 Ihe variable heal comcnl or Ihe IigJ1ltc f\lel which allows Ihe ere"lion ofoxygen_

rich condilions in Ihe hoiler.

AI-A8
APPENDIX Al

Techni""l Fea,ibility A,s.essmont Details for NUx Control Teehnolog,e,

NOx BAcr Analysis Stndy

A.1.4.2 SNCR and Reburn

Various forms of SNCR could potentially be installed downSlream ofseparaled overfin: uir and various

lypes of fuel rehum, to reduec NOx emissions prior to a boiler's Ilue gas exil. SewroJ oflhesc examples

were already described').",lO,lI,1m,". Conventional gas (CGR) Ur coal rebum systems, by and large, have

not been combined with forms ofSNCR. ahhough atlell.,t one vendor (GE Energy) has promoted u

combination of conventional gas rehum with SNCR and ovcrlire air systems as "advanced" gas rebum.

Only one example ofpermuncnt instalJu(ion of SNCR with conventional gas rcbum (und overruc uir) on u

lilngentially-fired b"iler was found in availuble teehnicalliterature'O and vendor expcrience lis15". The

vcndor (GE E"ergy) that provided the advanced gas rebum system at 120 MW NRG Somerset Station

claimed NOx cmissions were reduced by44% from a baseline of 0.45 down to 0.25 lh/mmBlu with

overfire air alone; an additional redue~on of20% resulling from convenlionaJ gas reburn Wilh overfire

air, down lo 0.20 Jh/nnnBtu; und further decrease of 45% down to 0.1 I Jh/mmBlu using gas rcbum with

SNCR wilh an unstated amount of armnonia "lip, for an uverall reduclion of75% from uncontrolled

baseJine".

No examples ofac(ual demomlralion Or permanent instalJation ofSNCR with cunVC"ntional gas Or coal

rcbum (and overlire air) on cyclone-fir~'XI boilers were found in a search of published and proprielmy

tcchnioalliteratnre_ The lack ofexperience with these combinations on a cyclone-fired boiler, especially

for lignite-firing, m"k<.:s thc application for MRY Station'" boilers infcasible_

FI.GRTM bas been imlalJed wilh SNCR for NOx emission reduction on seVC"ml pulverized coal boiJers,""

discussed in lhe following suhsection_ A potl"TItial advamage ofFLGRTM over conventional coal or gas

rebum techniqucs is that 'he former is genernlly compatible with, but docs not require, the inSlalla'ion and

O[lC",tion of SOFA.

Rich Reagent Injcction would appear to be Jess capable of being combined wilh fuel rebum, especially

conventional fueJ rebum ahcmatives wilh high amounts ofrebum fucl injcction. This is due to the

expected need 10 idJe (e_g. not fire) up to two oflhe seven cyclones when operating Ihe rcbum syslem al

full boiler lood. In this case, tite cooling air inlroduced into the idJe cyclones, and any convcying air

injected with pulverin:d rebum coaJ (or if nalu",l gas is injecled with recirculate<! nuc gus), arc expccted

to count~,.ael Ihe fuel·rich condilions of the air-and fuel-slaged cyelones ope-r",ing substoichiomelricaJJy_

This will cause a portion of the "mine reagenlto be oxidized in the lower furnace. cr""ling NOx

emissions instead of converting them to nitrogen and wateL No example of actnal demonstration or

permanent inslOIJation orRRI with rebum (and ovcrIirc air) on cyclone-fired boilers was found in

Minnkola Power CooperaIIVe, Inc. AH9 Durns & McDonnell
NO~ BACT Analysis Shldy

_.-.

APPENDlXAI

Technic"1 i'ea,il"lily Asse"mml Delail< lOr NO~ CODlTOI Technologic'

UVUlInhle l~'{;hnieJllilCTatu' e Or vendor cxperienee l'sls. This combinatioo is consLdernl infea'ihle al Ihe

present time_

Hyd, ocarbon-enhanced SNL1l (c-r.. NOxSlarTht ) may pOlCntially be com i>im;d with nil Iype' and fomll of

reburn prcviou,ly discussed, since lhc lucalion of Ihc enh"ntoed ammon", i'ticelion nozzles ""ill he above

(beyond) the elevalion in the middle furnaec where "ny rel1Um fuel Hhould be reaelcd. No c~amplc of

aclu" I demonslrali"" or pel'manent in,'allallon ofHE-SNCR wilh rcburn (and overllre air) un any coul-

!ired ulilily boilcr~, espee",lly cyclone-fIred umts, wa~ [ound in available le<:hnLealliler~ture or vendor

<:xperiencc lisls. Thc advanl"gc lhat IIE-SNCR presenls is Ihe polenli"l for ~"eater_lhan_SNCIl_lcvcl" of

NO~ ,educlion wilhu<JI ,igmficant amounts of gnseouo hyd, oearbon hei"g required_ I3ctnlL';e of a Jack 0 [.

c"pcTience wilh IIE SNCR applicd 10 cyclonc builers, and "One wilh ,ignilicanl amnunls of fucl reburn,

Ihis combination ha, not bc"n Investigalcd LUI1her, und wa, nOl included in the control and cO'I_

drectivcnc.<s "nuly~is for NOx controls.

A.1.4.2.1 Amine-Enhanced FLGRT'" (AEFLGRT"') or FLGRTM + SNCR

Fuel-leall I':"S reburn has been ctlmbined wilh SNCll as a hybnd r",m of"mine reJgenllechnolob';~oOn at

kasl !"Lve pulveL'Lzed eoal-G, ed uhhly pnwerphmt~ retrofil inslaliallOnS wiLlun the llnLted SI~lcs. Tlli'

combinalion of lechnologic, allows Ihe bOllcr lo bc operale<1 WiIh FLGK'" alone, l'LGRn-, and SNCR

~illlullanct>usly, or SNCR only (wi lhoul SOFA) for the' specific level of control deslr,",l nr reqllircd.

No c"amples of actual demonstralion Of I,ermancnl in,lallalion ofFLGRTM + SNCR (with or Wllhoul

ovcrfire air) applied 10 a cyclone-fired bOiler W~TC [Gund in avaibbk l~chnical[il~Talureor vrnd'"

cxperien~" lisl1;, n\e vendor (Fuel Tech) Ih'" provlde,1 the AEFUiR' Msy,lcm al Mercer Slalion olaimed

NOx emi'Slons \Verc reduced by 60% (from a ha,elinc of 1.4 down lo 0.56Iblmmlllu) wilh 5 ppm

ammoni" slip-",'Ihoul ovemrc alL A leehmc,,1 paper provides mOTe delail,". Anolher lechnical pap~T

.,Ialed lhat I'LGR'" alone only ,educed NO., ennSSlOn, "pproximately 27% ITom tho 1.4 Ib/mmBm

ba,cline, down 10 I.OJ IhlmmHlu".

An AEFLGR'" ,y~lem (wilh Of withoul SOFA or ASOFA) muy he pol"nli~llyapphcd 10 a <:yclone.jJ,ed

boilor. Thc Il1gh c"pilal and opcnlling cosls as~noialed wilh applying fuel lean P-' rebum i' expecled to

makc Ihis cconomically unmtr"ctIV(:, ,,,d the cxiSling ligniIe pre-Jrying venl purlS Wlillikdy limillhe

NO" ,.nission ,-educlion polenli,l of Ibe FLGRu, eun,poncnl iLin,lallcd without ihc udvanced form 0[·

;>;.

Dum' & McDonnell AI·50 Minnk<>la power Coopora'io", Ine.
APPENDJXAI

Technical Fc"ibility A",,",mcnl Dd.il, for NOx COD[[ol Technologies

NOxDACT,

SOFA_ The lock ofexperience wilh this combination on any cyclone-fired boiler, especially fOL

firing, makes this comhination infeasible for MRY Station Unit 1 boiler_

MiDnkO[a Po_rCo~peTalive, Inc, AI-51 Bums & McD~nncll
NOx (lACr Analy>i. Sluuy APPENDlXAl

Teehnic,l Fe,,->ibility 1I',",ssmenl Details for NOx Conrrol Technologies

----------_.--

Technlcallilerature References:

"B&W's Advances on Cyclones NO" Conlrol Vi" Flid and Air Slaging Technologies", by I'arzan,

B.. Maringo, G.• lohnwLl, D. W., 3ml Wong, D,K, (Babcock & Wileo". Co.), Ileard, CT. (Ea5tman

Ko,bk Company). ,mu Brewsler. S.E. (Tenne.«ee Valley AUlhoriIy), pn"c'IIleu "t lhe El'RI-DOElOPA Combined Ulilily Air P"llutanl Conlrol Symposium, Allanta. GA, AuguSl 16-20, 1999.

Available al ll&W's internet web,ile, htlp:!!www.babcock.com/pt<!!/lllpdffBR-1683.pdf

l 'The l':lale oflhe Arl in Cyclone RoMr NO" Rl'dul'lion", by O'Connor. D,ve, llime,. Rick, and

Fa~ehi"no. Tony (Electric Power Re,earch InSIilute), pre<enled allhe EPRJ-DOE-EPA Combined

Ulility Air Pollulant Conlrol Symp",ium. Allanl", GA, Augu,l 16-20, 1999.

3 EPA Dockcl OAR-2002·0076·0446 Tcclmi"al SUPPOlt Documenl lor BART NOx l.imil" tnt Eledric

GL"Tln"lmg Uml" E"cel Spreadsheel 6flS/200S, pO"lCd 0" lheir wcb,ile: from EDUCK.ET al

hllp:11dockcLcpa.govI ~<l]" pullldolEDKSlafill"mDel" 11 View'lobJec II d=O 0007d4 ROR4S(, 2b; tl, j, is

n"oeiutcd wjlh EPA Acid Rain l'rogram Clean Ail' MarkelS Divi,ion, Technic"l Support DocumentMelhodology I'or D~velorjng FlARTNO, PresumptIVe Limits. June 15, 2005, OAR"2002-0076·044.1,

4 Moboledll':A experie"oe li.'1 and techn"logy ""planalions, available fmm Iheir wC]'SilC nl

Illlr;/1www.mobolcclISJ.con16.Koj ecl~ in,I" Iia li 011>.hl, nan,]

hItp:11www.mobolC<::•• Sa.com/lce000logylrofa .hlm

5 "NOx RC(Juelion From A 44-MW Wall-Fired Iloller Ulillzing O"ygen Enhanccd Combuslion",

Prn"air. by Dool. I.awrence E. III, ~nd Flru,!icy, llJITon, prescnl"d al Tl1e MEGA Sympo.liom,

Was],ioglun D.C., May 20, 2003.

6 "COmhLJ~lion T~mpcring '" Conjunclion Wilh SNCR Reduc~, NO. Emi",ions Nc"r1y 6U% on a

Natural Gas Fired Cyclone Boiler", pO,IL-J "I th"ir mlemcl websile:

h1!l"1/www.rimcom.com1pdflMi<13 \~A.c.:. pdf

7 "Clean Co,1 Tcchnology: Rcbum 1'edmologie, for the Control ofNilrogeo Oxidcs Emissions from

Coal-Fire,1 Boilers. Topi"a! Report Number 14, May 1999", U.S. llq",rtmenl of Energy (DOE).

Posled allhe i"lernel wcll.,iIC:

h1111 :11www.J9..-••].energy.gov/pr~)~rarTl .•/flO...·r:.y.• I<:"../mlbIi"" 11 onsiClean Cool 1'01'ical RcporL",I0I,i

caI1.4.·p4f

8 "Clean Coal Technology Program,,: Projccl f"el Sheels 2UUJ. Include" Clean Coal TecOOol"gy

Dcmonslmlion I'rogr~m. as of May 2003, OClober 2003", U.S. DqJartmenl ofEnelgy (DOr.).

Availahle 10 Ihc public from lh" N"IJOnall!nel'f'Y TedlL\olngy l.aboralory's Clean Coal Teclmology

Comp"ndiom: hItR'!i..W\\',,'.1" ".1" govIllI'ojcc I~fcc leiinde,. hImi.

9 "R"buming Projecl, III (he Departmefi I ofEnLTgy'o Clean Coal TechnoloGY Dcmomlmlion Prq,""'"'"

by Mann. AI and Roppel, Tom (Pars"n~ Corpomlion), and Sarku". Tom (Nnlionnl encrgy Tcdmieal

Lahornlory), prc:;enl"~l a! lhe 20114 DOE-NETL Conle,-eIlcc On Rcbummg for NO" Contlo1.

Morganlown. WV. May 18, 2004. A rebum-related document (an Ol,~al"'{l vC"T'10n of" poster from

L1w M~y 18 Con[LTC"TIC") i" lilled ·'l':cOl'ccnn:1 On Rcb"miog 611/2004" by AI Mann and T0'" Rupp~l,

Parsons COTpOrnliUII, uvuil"ble on-line at:

h!lp:II~'L~etl.doe.gov/pul,licnli"nslpro"eCJ!ing:,.I04!NO~!j1os1e"'lRcbuming%20Scm:ecar.d.pdf

,'i

, .,

BlUrb &: McDonncll Al-JL Mint1kOIO Power COOr~rdli\'c. Inc.
APPENDIX Al

Technical Feasibility Ass",",mcnt Delails for NOx Comrol Tcchrmlogics

NOx BACf Analysis Stntly

to "Experience With Rebum for NOx Emissions Control", Engelhardt, Don, Payne, Roy, Moyeda,

David, Folsom, Blair, GE Energy, presented at the 2004 DOE-NETL Conference 00 Rebuming; for

NOx Control, Morgantown, WV, May 18, 2004.

11 "B&W's Reburning; Experience", by Farzan, H., Maringo, G., Yagiela, A., Kokkinos, A. (Babcock &

Wilcox, Co.), presented al the 20M DOE-NETL Conference On Rcbuming for NOx Control,

Morgantown, WV, May 18, 2004.

12 "B&W Cyclone Rebum Leads to NOx Reduclion, Wisconsin Power & Light Co. Nelson Dewey Unit

No.2" (cusc history from B&W's internel wcbsite

hup:ffwww.babcock.comlpgglps/casehistories.html. daled 1997).

13 "Reburn Technology,Applicalion Guidelines", Moyeda, David, Hartsock, Don, and Payne, Roy, GE

Energy, prcst'fltcd althe 2004 DOE-NEI"L Conference on Rebuming for NOx Conlro~ Morgalilown,

WV,MayI8,2004.

14 GE·EER experience h"l, SC"plembt'T 29, 2005. For wull-fired coal rebum, and gas rebum wilh SNCR,

see "PowcTpl~nl mosaics: paving lhe way 10 0.11 1\lIMMBtu wilhout SCR", by Folsom, BlairGE

Energy, published in the March2004 issue or Modern Power SystenR

15 "Predichons offLGR ~l CommonweaIlh Edison's Joliet Unit 6" by NGB Technologies, posledon

their websiIe: h tlp:/Iwww_n gglec h. comlsubwge"fprojIjoliel results.hImI

16 ~FLGR Aclvisor s": A Boiler Evnluation Tool for FLGR-Buscd NOx Reduelion Systems by NGB

Teohnolog;es Inc., poslt,,1 On lheir websile: http;/fwww.ngblech.comlsubpoges/projmm adv;sor.pAr.

17 "CfO Evaluation ufFucl Lean Gas Reburn (fLGRTht) and Selective Non-Cutalytic Reduction in

Owensboro Municipal U~hlies' Elmer Smith 5lalion", by Wang, David H_, Cremer, More A., Adams,

Bradley lL (Reaclion Engineering International); FrizzeIJ, K.D. (Owensboro Municipal Ulilities);

Dusatko, G.c. (Sargent & Lundy), presented at th. 2001 US EPAfDOE MEGA Symposium on SCR

and SNCIl.s, Chicugo,lL, August 20-23, 2001.

18 Fuel Tech experienoe list daled 1/28/2005.

19 SNCR "While Paper", Inslitute ofClean AirCompanies, Inc. (ICAC), SNCR Commillcc, May 2000,

Fuel Tech website http://www.fucltcchnv.comfpllrrrPP-534.po;l.f.

20 fUM experience list, September 3, 20{)4_

21 "NO~SLarTM Plant Demonslrdlion, October 2003", by Morris, K.W. and Hesselrnan, G., MiL'illi

Babcock (US), presented at the 2003 UK DOE Conference on SCRand SNCR lor NOx Control,

Pittsbmgh, PA, October 29-30, 2003.

22 "lnstallalion ofNOxStarTM Systorn al TVA Colbcn", by Morris, Keith W., Mitsui Babcock (US),

presented at the Coal-Gen 2004 Conrerence, July 28-30. 2004, Overland Park, KS_

2J "Improved Rich Reagent Injcclion (RRJ) Perrormunce for NOx Control In Cool Fired Utility Boik-n;"

by Cremer, Mare A. ~ml Wang, IIuafeng D. (Reaclion Engineering Intenlalional), Boll, David E-

(AmcrcnUE), Schitldler, Edmund (RJM Corporation), and Vasque7, Edmundo RMT,lnc. (AlIiant

MinnkU\d Powe, Coopernli,'c, ITIc. AI_5) Burns & McDotlnell
NOx IJACr Analysis SLudy APPENDlXAl

Technical FeasibililY Ass<>smo;nl Dc!.>il' fo' NO" CunlTOJ Teclmolngies

Energy Cnrp.), presenled al 2003 U.S. DOE Conference on liCit and liNCR ror NOx Conlrol,

Pillsburgh, I'A. Oclober 29-30, 2003.

24 "D~,ign and Demnnstralion ofItich Rengenl Injections (MI) P~Tform"nceFor NO" Redudion al

Conneeliv's BoL. Engl"nd SI"li,}O" by Cremer, Marc A. an,l A(l.ms, Bradley R. ("""clion

EngineeriLlg Inlernalio,,"l); 0 'Co""or, D"viu C. (Eleclric I'ower Itesearch Institule); Bhnmidipall,

Venbla (Conectiv B.L Engbnd Sialion), and Broderick, R. Gifford (RJM Corporalion), pl'e.,e"led al

Ihe 2001 US EPNDOEJEPR! MEGA Sympu,ium on SCR and SNCRs, Chicago, [I., Aug"sl 20-23,

200 I. (availahle Jeorn REI', internel weh,ile hllp:llwww.rcaclion-cng.eom/Jonwl..~d....ITimol!...pdD

25 "Dc'111onslralion of Rich Reagent Injeclion lor NOx O.,"lrol In AmcrenUE's Sioux Unit I" by

Cremer, Marc II. ,mu Au"m" Bradlcy Il. (Reaelion Engineering IJ\lernalio"nl), Bull, David E.

(AmcrcnUE), and O'Collnor, Davld C. (Eleclric Power Re'earch Ins~llIle), presenled allhe US DOE

Conference un SClUSNCIl for NO" Control. Pitt,burgh, PA, M"y 15-16, 2002.

26 "Evalualinn of("o,l Effecll __e Non-SCIl Options for NO" Contml in PRE fired Cyclone BOllers" by

Crem~r, Marc A.• Wang, David 1·1. and Adnms, Brndley R. (lleacllon Engineering InlenlOllOnal);

Boll, D.vid 10. und Sluckm~ycr, Kcnnelh B. (AlllCrenUE), pl'e.,ented JI Ihe We'lern Fuels

Symposium, 19'" Inlernational Conference On Lignilc, Brown, anu Subbilulllinou, Coalo (f(lrmc"fly

Low-Rank f "eI,), Oolober 12-14, 2004, Billin.:." MT

27 "NOx Emi",iollS Below 0.15 lb/Mblu Achieved in a Cyclone_fired ROller U,ing In-Furnace

Cunlwl", by C. emer. M., Adams, Il., nm] Chiuuo, A., (Rcaclion Engineering !merna'io""I);

Gie."'~nn, c., Sluckmeyer. K., and Boyle, J. (AmerenIlE), prc&enlcd al Inc Puwergen Inlernalin".1

2005 conference. Deccmber 6·8, 2005, Lus Vega" Nevada.

28 "Ash and Mel'cu,y Reha~ior in SCR Cal"ly'ls When Firing Subbllltlllinou, nnd I,il",lc CO<1ls'",

Energy & Environmc"fllli Research Center (cERC) of the Uni "e"ily ofNorlh Dakola", Ilen.'on,

Sleven A., taumh, Ja,on D., Crode"f, Ch"rknc It., and Pavlish, John II. subm,uttJ fur publio"lion by

fuel Procc%ing Technology magazine, 2004.

An ediled vel'sJOn of lhis paper was published us:

"SCR C"laly,t Porrorm.ncc in Flnc Go,". Dcr've~ from SubbiluminDu, au~ l.i~n[le Co.I'" by

Fuel Prnce.'Sing TeciUlology, VQlollue 36, 1>"ue 5, 25 FcbrWlfJ' 2005. P.ge.< 577·(013

Sluvcn A. Bc",,'o", Joso", D, !.31ll"b, C1",rleJl~ R. CJlJck~r ami John H. PavlL,h.

29 "In-Silu Mim SCR Reoelor" study. available (for pllrcha,e from) Electric Power Researoh lnslilute

Inc.', (EPRI' 0) inlcrncl wcbsilc "I

h lip;IIwww.epn.com.l•.!.\v.lell...~!.B.I..1i ",tieid- 2 7J05&m"rkc toid 27_U_61 9&tame In irl 270677&valu c~

O'iTOn.O

)0 ·'Recenl Expcric"flCC Wilh Hilachi Plate Type SCR Calaly.<l", Morilfl, Isnto, Og1Lsahara, Tom

Fr"nkJin, Ilowa'd N., Bnbooek-Hilnchi H.K. and Hilachi America lechnical p"pn, prc,;ented 10 The

Inslilule of Clean Air CompanJes FOnJl11 '02, february 12-13, 2002, Washinglnn, D.C.

J I '·l'erformanee orScleClive Cllnlylic Redllclion On Coai-Fil'ed Sleam Generaling Unils" I1.S. EPA

Office of lIir aod ltadialion ACld Rain Program Final Report, (620<1-J), June 25, 1~97.

]2 ·'Rolating Opposed firc Air (ROFA) and SNCR'", by Shilling. Mark and ToIl"maker, Gary (Carolina

Puw", & Lighl Co.), rre.<enled allhc 2002 DOE-NETL Conference on Unburned Curbon on Ulility

I'lya,h, May 14, 2002" I'iltsbmgh, I'A.

Du'os&McDUHndl r.-tirrnkula Po",e, CoopeI3LJ\'e, Illc.
APPENDIX Al

Technical Feasibility /I,,=mcm Details for NOx Control TechllolQgio,

NOx BACr Analysi, Smdy

33 "Injection ofUrea lhrough lhe Rotamix System [0 Oblllin Improved NOx Reduclion", by Ra]<lon,

John und Haddad, E<lwin (Mobolcc USA, Inc.), presel\ted allhe 2003 U.S. DOE Conference on SCR

and SNCR forNOx Conlrol, Piltsburgh, PA, OClOher 29-30, 2003.

34 "SCR Levels ofNOx Reduction wilh ROFA ami ROlllmix (SNCR) at Dynegy's Vermillion Power

SlaLion", by Coombs, Kristoph~T A. Sr. (Dyncgy Midwest G~"T1cration).and Crilky, Juy S., Shilling,

Mark and Haddad, Edwin (J\1oholec USA, Inc.). presenlc<! allhe 201M St"ck Emissions Symposium.

Clearwater Beach, FL, July 28-30, 2004.

35 "First Commercial InSlnllation ofAmine Eummccd "11~1 Lean Gas Reburn On Uuils I and 2 al Public

Service Electric & Gas Merccr SLation", by Gomez, Andrew F. (public Service Electric & Gus

Company (PSE&G) McrccrGeneraling SIa~on), Dainoff, AlexJn"~"[ S. and O'Leary, John II. (Fuel

Tech.lnc.), and Schrecengosl, Robert (Energy Systems Associ"tcs), presented at lhe 2000 DOENETI. Conference on SCR and SNCR for NOx Control, Pittsburgh, PA, May 17-18, 2000.

* ** **

Minnkola PowcrCooper;Hive, Inc. At-55 Bum' & MoDunnell

APPENDIXA2

u.s. NOx Control Relrofil ProjccLs

A.2.1 - U.S. Cyclone NOx Reduction Projects Summary

NOx BACT Analysis Study

1962 vintage

easlern biluminOuS coal

SELECTIVE NON-CATALYTICREDUCTIONtRICH REAGENTINJECTION

Cyclone-Fired Boilers

Conectiv (rormerly Atlamic Eleotric)

ilL England Unit 1 Cmslicd Coul, smgle-wull cyclone-fire<J

138 MW B&W boiler aqueous urea SNCR, 1995 slartup

BOller has only 3 oyclone burners, armnged "lover 2" slyle.

RJM implemenled commercial Fuel Tech uroa-b""cd SNCR system inslallalion in 1995 after short-lerm

(3-monlh demopslralion lcst) i~ 1993-1994_ 31 % NOx reduclion claimed, from 1.311bfmmBtu NOx

baselinelll for SNCR only; RJM claimed 35% reduction rrom I.]Ilb/mmBlu down to 0_85 IblmrnBtu

(wilholll overfire air) wilh ureu-lo-NOx NSR = 0.85 (RJM expcriencc list).

Added cighl temporary roo pons (three nozzles on each lower sidcwall, and two nozzles on !he upper

rear wall, and perrormed one monlh demonslmtion paramelric tesling ofo"erlire air only (wilhout SNCR

Or RRl), at 120 MW nominal \)(Iiler load and cyclone S.R. e= 0_90 in 1999. REI claimed 55% NOx

reduclion from a 1.2 lblmmBtu unconlrolk<l NOx baseline to 0.55 Ib/mmBlu with OFA only, with stack

CO emissions below 50 ppm_ For Rich Reagent Injeclion; REI claimed 25-30% NOx reduolion for RRI

down 10 0.381b/mmBtu from controlle<l buseli~e wI OFA alone of0.55lbfmmBlu NOx and a RRI urealrl-NOx NSR = 2; also showed RRI+SNCR w/ OFA reduccd NOx 55% to 0251bfmmBtu (J4% beyond

RJU wI OFA), for an overa1179% NO" rc<luct;on with a SNCR urea-lo-NOx NSR = 1. Measurcd less

than 1ppm ammonia slip during RRIlesting, < 5 ppm slip for RRI + SNCR. No significant increase in

CO emissions during RRI teslin!f).

Source: (1) ICAC While Paper; RJl\II experience lisl; t')REI 200 j Technical Paper.

Conecl;v (fonnerly Allaulic Electric)

BL England Unit 2 Crushcd Coal, cydone-fired, single-wall-fired 1964 vintage

160 MW IJ&W boiler SNCR, 1996 slartupeaslem bituminous co.1

RJM implemenled commercial Fucl Tech urea_based SNCR syslem in 1996, claimed 36% n:duclion from

1.36 Ib/nunBlu down lO 0.85 lblmrnBlu, urea-lo-NOx NSR = 0_85 (without owdire air)ll).

An OFA sy~tcm was added iu 1998, rc"Sulling in NOx emissions of0.33IblmmBtu, for an oV~'Tall

NOx reduction of76%.

Source: IUM experience lis!. (Also lisled in (1)ICAC While Paper).

Amcrc"]]UE (formerly Union Electric Co.)

Sioux Unit I Crushed Coal, opposed-wall cyclune-lired 1969 vinlage

500 MW B&Wboiler Rich Rc"gem Injeclion demonstralion 1<Sling in 2001

Boiler has 10 cyclone burners, lIITanged "2 over 3" style, on opposite w.ns, and fires a blend of85% 10

50% weslern sLibbiluminous (Pill) cool, with 111;nois biluminous coal, pelroleum coke, and lire-derived

fuel.

losl.llcd lwcnty temporary IUU ports (six nozzles on each lower sidewall, and rour nozzles on each front

and rear wall), and performed one month demonstration parametric lCSllng ofovernrc air only and initial

!csling with RRI in Augus12001, followcd by additionaltestillg in March 2002, and lhe second quaner of

2004. Added 8 RRI ports (1 in each sidewall, 4 in each front and rCar wall) and 14 SNCRpOrlS (5 on

upper front wull, 9 on upper rear wall) lo lhe furnacc in curly 2005, followed by three weeks Ofp;lmmclric

tesling and J days of conlinuous tesling ofRRI wilh SNCR and doeper-slaged OFA_

Tested in Augusl200 1at lower furnace SR approx.=l.O, 0.551blmmBtu wI OFA only, only 15% NO"

reduclion wi RJU, zero ammoni•.slip.

Minnkol. Power Cooperative, Ino. Dums & McDonnell
NO~ BAel' Anolysi_, Siudy APPENDIX A2

U_S. NOx Conllol Relrofil Projccl!.

T~.,t~d i" March 2002 allow~r lumace SR approX-"--D_95, from 0.381b/mmBtu haseline wi OFA only,

achieved 29% NOx reductlOn wi RRl down to O.27lbfmmlllu, NSR=3, 7..,ro ammonia slipt')oo

(ns,llmc ble-nd llfPRB and 11linois bilominou" conI w/lirc-dcrivcd fuel and pelrole,,,n "okefl_

OjJualion in 110,' s~coll(l <1llnT1~r 2004 show~d aclual slack NOx averagcd "mum] of0.30 1l>lmJTIBlu wilh

OFA only and lower li,rnace at" cyclone SR arnund O_H8 Imming n 85% PRIl, 15% JIlinois 116

bilummous cool blemJ, prc",mably at ~~O MW_ This IS 0 75% NOx reduclion from a 1.191b/mmlliu pre-

"onlrol b"""line, REl uoing Cf'O modeling predicled NO" ,lawn to 0, 181blmmB\\1 wilh RRl+OFA, ond

helow 0_15 wilb ltR11 "NCR under similar deep cyclnne oir-.<I"ging (1.19 10 O_2X Ib/mmlltu is 76%

reducllon, 0_1 vs 0.28 j, on mJd,llOnaJ 36% reduclion w/IUU, ond 0_14 vs 0_2~ is a 50% rcduclion wI

RRI+SNCR, for On overall rcdoelion of 88%tl

,

Test~d in May 2005 al 4g0 MWg With. lower fumace Sll approx_ = 0_S5-IUS, 76-83% redllclion Ii-om 1.2

IblmmBlu b"stllne down 10 w, low w, 0.20 lblmmBIU wI SOFA only firing 80% PRB, 20% IIllnoi" 116

hitummous coal blend; additionol 15-39% NUx reduction wI RRI, 10 as low as 0_15 IblmmBlu from 0_20_

0,281blmmBI\I bllsdinc wi SOFA only al urea NSR v,meu belween 1 ond 4, wilh one ppm llmmonia slip;

achJeved addilional NOx reducllOn wi RRI ! SNCR down 10 0_12 IhlrnmDtu, NSR=~, ammouia sliplO

ppm Or less_ RR] ~SNCR wi SOFA NOx redudion percenllige vllritd from 15% to 50% below SOFAonly levels, wilh NSRs belween I and 4.5_ SNCR alone had lJ% (NSR=I) 10 32% (NSR=I) NOx

re<luelion Wilh ommol\ia slip around 1-2 Pl'm~_

Source: "I REI 2002 on<120031'cchnicoII'0p"n;; (') REI 2004 Techmcol p"per;* REI 2005 Technical

poper.

REBlIRN- GAS, CONVENTIONAL

Cvclnne-Fircd Boilers

COTlSlcll" li"n Fnergy (Io,merly Ball,"'ore Gao & Eh:l.-ie)

CJ'_Cr"ne Stalion, Unil, I & 2 (MD) Crushed Cool, eyclone-Jired, eoslem blluminous coal

2,200 MW B&Whoilers (foureyclones ciwh) 1961, 1963 vinillge

GE-EER ConvcntlOnal Gas ReblPm, 1999 slmlup

A<1,lt<l gas .,upply piping, mete, ing, hal\g~,", suppnrL,; ['chum injc"CloT> and ""ollng air duel,,-'ork, OFA

duclwork, injeclion nozzles ond woll pOlis, field (assume ea.,te, n hituminous coal)

GE-EER claimed Gos Rehum wlth Of'A lowered NO~ bclw<;C"Tl 60% a",165% from bll,dines of1.50

Iblmmlliu 10 belween O.GO and 0,52 lblmmDlu, 01 fulllood wllb rehurn opemlion. No claims ofperceot

rcbum fuel or percenl orA included in C,E-FER', experience Ji&l.

Anolhcr Icchnic"1paper showed Ihi, insl"ll"tion of CGR operaled with 25 p<-TCcnl rcbum fud'i.

SOllrce: Sept. 2005 GE.EFR experience I,~I; ('IDOE.NETL ScorccanJ un Rebumillg 6!Jn004 (from 200~

Rebum Conferen"e).

City Waler, Li£hl & Powcr

I _.h.,ide llnil 7 Crushed Crull, fronl-wall cydone·Jirc-o, midwe.'lero hituminous coal

300,000 Ib/h.r s(eam B&W hoiler (approx_ 33 MWe equivalent, two cyclones) 1961 vinlage

Springfield, It DOE (1eon Coal demOnSlmlion projeci (in~luded sorbenl injeelion)

GE-EER eonvenlionol go, rcbllm wi OFA 1992 slartul' (CC,R not eurrenlly opemling)

Vcndor claimed 10 lower NOx hy 66% [rom 0_95 Ib/rnmlllu ba,eline lu 0_32lh/mmBtll, A GTi·EER 2004

1eehnieal paper showed 25% rebum [uel yJelded mmimum NOx emissiom('l_

A DOE NE1"L lechnical poper showedlhis demonstration ofCC,R from 5/93-]0/94 (assume wilh OFA)

wilh 23 pereenl rehum fuel reduced NOx 60% from 0_97 10 0.J91blmmHtu 1'1_

Source: Scpl. 2005 GE-EER exp"riencc lisl; ('IGE_HER 2004 Technical ]YJp"r;(SIDOE-NEfL 2004

Rebllm Conference Techrl ie.l paper_

E",lm"n Kodak Company

Kodak Park Boile" I & 42 Crushed Cool. fronl-wall cyclone-fired, 1%4 & 1966 vinlage

Bum, & M"Do"nell A2-2 Minnkola Pow~r Coupcmlive. Inc_
APPENDIX A2

U.S. NO>: ConlraJ Reuant Prnjccls

NOx BACT' Analysis Srudy

400,000 lblhr steam B&W boilers (approx. 50 MWe cquiWllenl, Iwo 8_fldia. cyclones)

Roeh"Ster, NY eastern bituminous coal

H&W convc'1Itional gas reburn wI OFA December 1998, July 1998 startups (slill opcruling)

Commercial installation ofCGR, wilh (I) gus bumeradded 10 each si<!cwall + (2) largc and (2) small

OFA porls added Lo fronl wall above cyclones, ulilizing higher reburn gas pressurc (vs. Boiler #43)

requires no flue gas recirculation; {Very small Hlrnace wI cyclone SR not <1.01·

B&W claimed ",hum wilh OFA lowered NOx hy 50% from 1.20 IhlmmBtu baseline 10 0.6Ib/mmHLu.

B&W graph shows 10-12% peroenl rebum fuel 10 achieve 0.6Ib/mm13tu and 23-24% rebum gas inpul 10

reach 0.33 Ib/mmBlu NOx (7J% reduoI;on)(1).

Anolhcr ledmioal pap-er showed NOx lowered by 52% from 1.25 Ib/mmBtu baseline to 0.60 lhlmmBtu

with 18 percent relmrn fudsl.

Sourcc; [7)n&W Technical Pap",,; 1')nOE-NETL ScorecanJ on Rcbuming 61112004 (from 2004 Rehum

Conference).

REBURN- GAS, CONVENTIONAL

Cyclon<>-Fircd Boilc,", cOnljnuell

Eastman Kodak Company

Kodak Park Boiler 43 Crmhed Coal, front-wall cyclonc_fJred 1968 vintage

600,000 Ibihr steam B&W boil"" (approx. 60 MWe equivalent, two cycloncs)

Rochesler, NY eastern bituminous coal

B&W conventional gas rcburn 1995 st:lrtup {sLill operating)

-Commercial insloll~lion ofeGR, with flue gas recirculation (FGR) for injection m"SS momentum wI (I)

FtiR fan; (1) gas burner addc-d to enc h sidewall + (2) OFA ports added lion t wall aixlve cyclonc>. [Very

~mall fnmaoe/low residence time wI cyclone Sft not <1.01

13&\'11 clu,med reburn with OFA & FGR lowered NOx by 50% from 1.20 Ib/mmBtu baseline 10 0.6

Ih/mmIltu. B&W graph .hows Ig% percent rcbum fuel to achieve 0.6 IbfmmBtu and 29% reburn gas

input to rC'deh 0.36 IbfmmBtu NOx (70% redoetion)m.

"Another technionl puper showed NO>< lowered by 56% from 1.35lblmmll1n baseline to 0.60 Ib/mmBtu

Jiith 18 perc""t rehum fucl(5l.

Source: (J)B&W Technical Paper; I" DOE-NETL Scorecard On R~huming 61112004 (from 2004 Rebum

Conference).

Tennessc"" Valley AuLhority (TVA)

Allen Slation Unil I (TN) Crushed Coal, cyclone-fired (se~en cyclones) 1959 vintage

JOO MW B&W ixliler PRB &western bituminous coal bleruJ fired

GE-EER Conventional Gas Relmrn, 1998 startup

C'AlmmerGiul instaliaLion added gJS supply piping, meLering, hangers, suppons; rclmrn injectors und

cooling air piping, OFA duclwork, injection non:lcs ancl wall ports, ficld T&C devices.

Reburn wilh OFA claimed to lower NOx 65% from baseline 1.20 Ib/mmBtu 100,42 lh/mmBtu) at full

load with reburn opcrmion. No claims ofpercent reborn f"cl inclucled. (TVA also installed duplicate

OFA sysLems On Allen Units 2 & 3 boiler,;).

Another technioal paper showed NOx lowered hy 65% from 0.E6lbfmmBtu bJseEne (to O.JO IbfmrnBtu)

with 7 perc""l reburn fuell

').

Source: Sept. 2005 GE-EER ~xpcriencelist; ('lOOE-NETL Scorecard on Rcbuming 61112004 (from2004

Rcburn Conference).

REBURN- COAL, CONVENTIONAL

Cyclone-Fired Boilers

Alliant Energy (formerly Wisconsin Power & Light)

Nelson Dcwey SLalion Unit2 Crushed Cool, cyclone-lired, PRB cool 1962 vinl~gc

Miankola Power Coop"mlivo, Jn~. A2_3 Burns & McDonnell
NOx HACT An.lysis Srudy APPENDIX A2

U.S. NOx COIln-ol Retro,,1 Proj<olS

110 MW Il&WhoikT J-cyc101l<S aero" fronl wall, 4 rcbum hu,ners I·

4 OFA porls acro" rear w.ll, aligned vertic"lIy in culumns.

US nOE Clean Co"l Demonstration project of B&W's Conventional Cu"l RcblJrn, I991 sLartup (sJIlce

di~culllinll<:d) n<1,1c<l ~u"l supply piping, rehum lmmers wilh nile g<lS recirelll"lio"" OFA ductwork I dual

ZOLle pn,1s; coal feeder, pul,-enzer & I'A f"n, I"stnl wilh PRR aod billl",i!\o~s coals_ (western

s~bbllllmJllOllS cual)

B&W ehtimcd rebum operalio!\ lowered NOx by 57% fr(}fll b<lseline of 0,8) mmBlo I" 0.)8 Ih/mmB lu al

fullloadl!l_ Apprnx. J()% p"re~nl oflulal fud inpul supplied as rcbumjheL Increased unil oulput by 10

MW, incrcased fly",h unbum~d carbon by 4% (U-12% vs 9-1 R%), decreased f"macc exit gilS

lernper.Hure (FEGT). 01'A ports li,ted in B&W e>.pericncc lisl.

D&W shows full 10,,<1 NOx w/o rcbum W'S 0_75 lbfmnilllll, and 0_29-0.J2 lb/mmHlu wI PRE fud d,mn~

rchum opera lion (57% deerease). At 75% load, 0.64 vs 0.29-0.32Ib/mmBtll. Al55% lo.d, 0.62 vs 0.29_

O.J 1 Ib/mml:Hu wilhoul ,md wilh [<:burn "Cl;valcdl

').

Anolhe, Icc1mioall'aper .,howed NOx lowered by 52-55% frum 0.82 Ib/mmBl<J h:lsc1illc (10 0.39-0.34

lb/mnilltu) wilh 25-~O pero~'Tlt rcbum fud'i.

Source, (7)2004 B&W Technioal Paper; (5)DUE"NETL 2004 Rcbuffi Con[crenee Technical paper;

(OJ E&W c",c hi~lory (from web,ilc, dalcd 1997)_

REBURN- COAL, MICRONIZ1:.;lJ, CONYENTlONAI.

CVdOD~~FiredBoiler.'

Easlman Ko(hk CompullY

Kodak Park #15 Boilcr l'mshcd Coal, frunl_wall eydonc-fircd, 1956 vintage

400,000 Ibill[ SlLonm B&W boiler ('I'pro,,_ SO MWe equivalenl, lwo cycloncs)

Rr>Che.'ler. NY enslcm billlminous co,,1

UE-EEll ml~'TomzL",1 coal rchurn I996 milial 'lartup (operaling since 1997)

Demonstration project perfonned wilh Dcpl. ofEnerb'Y's US Ck;m ConI Teohnology Program. Projecl

ad,led n"" gll, ,-e~irclll.lion for injection mass momentum, FGR fan and Iwo micronized 00,,1 p<Jlveriu-'TS;

(6) rebllll' walmJeotors added 10 rc<lr waJ]-i- (l) r~bum eoal injeolor Oil each ol'lhe ,idew.ll" wilil (4)

UFA porls "dded ueru,~ front w"ll "hove eyoloLle,('). GE-EER de.,igned and r<lbricated Ihe eoal mj~"Ctors

and 01'A ports. {Extl elllely small fum"ee and low TC,idcnce limc).

GE-EER cbimed rcbum + OFA w/FGR redueed NOx by 50% lrom 1.20 lblmmBllI b"scline to 0.6

lh/mmBlu. No clmms ofpercenl rebum fuel ",dud",L

Anoth<:r leohnieal popor sllowed IhlS demomrrralion ofmicronized coal rebum from 4/97"10198 lowered

NOx hy 57% from] .J6lbfmmBlll bosdine (Iu 0,59IblrnmBI<J) wilh 17 perocnt ,,,hum fud'l_

Source: "'DOE Tupic.l R<:port Number 14 (May 1999); GE-EER expelience lisl;15)OO£_NETL 2004

Rehurn Conferenoe Teehnic"1 paper.

REBURN- FUEL LEAN GAS !U:-'HURN

Cy<tone_Fircd Boilcrs

MidweSI Geneh<lion (Iormerly Commonweallh Eclison)

Joliel SI<llion 9, Unil 6 Cru,hed Coni, opposed-wall cydone-fired (nine cyclones)

340 MW ll&W hOller 1959 vinlage, ]997 ,Iarlup (fLGR h;,:; ,inoc been deeommi",iooed)

Energy Systems Assuci;,lc> dcmunstraled 25_)0% NOx redllobon using 5-1 0% of lotal ileal input os

rebum nalur~1 g.s i'ti~Cled (wilhout OFAi'I_

Another tecilnical 1'''1'"' showed lhis demonslr.llioll in eollahoralion wilh Go< Re,e.reh lnsiliule ofFLGR

10wlTed NO" hy 28-43% linm I.J6 Ib/mmB lu baseline (to 0.59 IblmmBlu) ",ilh 7 pcrcml rcbllm fud").

Souroe: (» DUe-NETL Scoreo,mJ un Roburnillg 6/112004 (fTom 2004 Reb~rn ConJerenee);

(10) NGB Technologie, Technical P<lpeL

Burns & MoDlllllldl Minnkot. 1'ower Cooperdtive, Inc.
IIPPENDIX A2

US. NOx Co~trol Retrofit ProjeoL.

NOx BIICT Analysis Study

1965 vinlage

Crushed COJI, froni-wall cyclone-fired

(lhree cyclones)

REBURN- FUEL LEAN GAS REBURN wiSNCR co"ti"ued

CVclone--:Fired noilers

OWl-'T1sbor<> Munieip<ll ULilities (KY)

Elmer Smith Unit I

150MWB&Wboiler

cm modelstu(ly only predioted NOx reductions from L59 10 D.39lh/mmBtu with OFA only (75%

reduction, 0.90 SR); 25-3D% NOx reduction lL,ing 6% of lolaI heal inpul"s rcbum natuml g"S injC<:lcd

ahove OFA; ~0-45% NO" ",duotion from SNCR with <5 ppm ammonia slipl").

Source, (U) REI Technical paper.

SeporHI~d OVERFJRE AIR

Cyclone--.Fired Roil...

TCIme."ee Valley AUlhority (TVA) Crushed Coal, cyclone-fired, 1959 vintage

Allen SIJtion UnlLs 2 & 3 (TN) (seven cyclones)

)00 MW B&W boilers PRE &weSIern bituminous coal blend

GE-EER Overfire air (duplicale of Allen 1), 1999 Slartup

GE_EER cl"ime<1to lower NO" with OFA alone up Lo 29% from baseline 1.20 lblmmBtu to D.8S

lb/mmBtu on UniLs U2 and 3 at full load.

Source: Sepl. 2005 GE-EER experience lisL

AmerenUE (formerly Union Elc<:tric Co·l

Sio~ Unil I Crushed Coal, oppused-wall cyclone-fired 196Q vintage

500 MW B&W boiler PRE!11linois Coal blend

]Joiler has \0 cyclone burners, arranged "2 over 3" styk. on opposile walls, and fires a blend of85% to

50% western subbituminous (pRB) "oal. with Illinois bituminous coal. petroleum coke, and tirc-<lerivcd

fucl.

A ien-port OFA system (five ports un each fronl Jnd rear waHl began operation in mid-2001, whi"h

red"c"d NOx emission' appm". 40-50% reduclion from Ll-1.3 (Jssumc av=ge of 1.19) clown 10 0.7

lbi':''-ffiBtu wilh moderate cyclone aiT_~taging (cyclone SR from 1.IQ to 1.0). (» Subseqllenllesling and

flll1load operalion al deeper cyclone aiHlaging (SRs ~.90) h:ls dropped NOx wiLh SOFA alone 10

around 0.3lblmmRln in 2004«1.

Souce<:: Il) REI 2002 and 2003 Technical Papers; (') REI 2004 Technical p"per;~ REl2005 Technioal

paper

Coal burning cyclone-fired ulility boilers in lhe United Slales lh~l have heen retrofitl"d with SepJrnled

Overfire Air CR teohnology arc listed in Table A.2-1. A large majority o[ the cydone-fired boilers lisled

bum western subbiluminous 00"1 (or PRR blended with midwestern biluminous coal).

Minnkola Power Cooper-Hive. Inc. A2-5 BWIlS & McDonnell
NOK lJACr A"aly,i, Study APPENDIXA2

U.,'L NOK (''''"lrol Relrofit Projects

TABLE A.2-1 _ Cyclone-Fired Boiler Overlire Air Retrofit Installations!"]

SCR rctrofil 511112004

SCI{ rttrolil 51OJ1200J

Similar 10 Julicl9 Unil6

SNCR demo May 2005

SCR retrofil 1211712002

SCR rmofH 6/0712002

SCR relrofit5/0112UOI

sm Ielrulil 5/0 WOOO

SCR «IIOJil 311 0/2{}(M

'-'~":'~;TI';lh~' .~AlJen Slali"n '~""m",~~=== ITnilS 1 .~'i"~,,"·~,,~"j"~"~"J."~""';'====PC~'""~"""j'j"'."~~~~~~~=-:::=1 1"".lletl 199~' UFA wI CGR relro1i";"""""'"R~ -

Allen Slati"n UnO[ 2 111'1011,,0 1999 T (Simibno Unil I, wi" C'GR) I"w SCR

Allm St'lIi"n Unil3 Insl,llc..t 1999" (.~imila, 10 Unil I, wlo CGR) h",'" SCR

A'bury UniL 1 Inslalled 511 011999 Empire Distri"t. BART-digi]'l"

[J"illy lJnil 7 IJlsl<dlcJ 200.1"" SCR 10 be i""alkd in 2006-7

Umlly U"it 8 JJls<.lItJ 5/31/2000 SCR rel,ofi1511112004

lJaldwin ITnit I Inslalled 12/.,111999 SCIl 'e"o!it 412~1200J

Baldwin UniT 2 luslalIcd 51812000 SCR rel",fil 4/1212002

Big Sll"'" UniL 1 l"slOlleJ 1012211997 pml or conve"ion LO PRB

BL England 1Tnil2 111smlleu 199~T prtvious SNCR TetrOLLI in 1996

Cl' wane Unit 2 J""alieu 2/111999 OFA wi CGR rtlrolit

Coffetn U"il I In"alled 2111200 I SCI{ relr"r,1 412 112003

Coffeen VIlli 2 ImLaIled lf9f2000 SCI{ TetrofiL 410912002

EdgewOle,Unil3 Instalkd 11(2001''')

Eclg'Wl1lef Unil 4 In,talkd (j/I9/200 1

Joliel 91 1"il (, Insl.lIed 200(f")

Kin"iJ UniL 1 Il1slallod 412R12000

Killc_iJ Unit 2 InSlOlled 512412000

Allen S. King ITn,t 1 In"olled 11130/1999

LaCygne Uni' I Instolled 212812000

L1ke Road U"iL (, In"alied 610112002

MichiROfl Cily lJnll 12 ImLaTled 411'J)<:""

Nelson Dewey Uni1 I Imlalkd ,ooi' ')

N'lson Dewey lJIIll 2 Imlalkd 200i'"

PmadJse Unit I In' tailed lll14/1998

Pamdise Unil2 In,l.lled 1218/1999

I'aradi'e Uni! J In>lalled 5/4/2000

Powe""" Unil 5-1 Inslrlllcd 61112003

l'owerl"n U"il 5-2 lnsl<llleJ 61112003

l'u",el1on Unil 6-1 Inslall"d 61 Jl2002

PoW<rlon Un" 6-2 In"alled )/~/l999

Sdl.llfer lJIIlI 14 ImlaIIed eo,ly 2000"')

Sibley UIIil] Instalkd 512412002

SibleyUrnl3 1"'lalied 51~1l999

SiOllX Unil 1 In,l.lIed 4/3012001

Sioux U"il 2 l"slalkd 4/.10/1997

Sink Lino Unil 4 Il1slolled 111200 I""

TannIT.' Creek Uail 4 1llSlallttl 5/1212002

Thomas Hill Unit I 1,,'I.lled Jone 20041'"

Tho",,,-, HJIl 11";12 1"'lallod November 2000""

NOle: 1 hi, l.bIc doo& "01 includc eyory iIl"olied lJ ,S_ coal_lired oyclone bOllcr OFA retrof,t pJOjecL

Source: ("'US EPA DockOl OAR-2002-007(,-0446 Technical Supporr Docl1mcnl r~r DART NOx I intils fur m,wjc

Genemling VIIil, Iixcol Spreadsheel6/1512005 (e~repl 0' no'od bol~w)

• Venuurcxperionoc li,,(GE Energy lor Allen Sioliun lJniL' I-J; RJM fur BI. Ellgland I1nil2)

(JlI Durns & McDonnell imemal dalaba.'o.

Cool hnrning ~ycl une-flred "'iliIY boilers in the Unil",,] Stales lha11,avc been "'Irefilled wi Ih SCR

leehnulogy are lisled in Table A2-2_ This Ji." inclll<Jes a1 Ie'" eighleen eyclune-li' ed buikrs bmni"g

wcslem subbiluminoU> cool (or ]'IW hlendeJ wilh midweSlern biluminous coal). The bighesl emission

lI,un' & McDonnell MinnkOLn Power CuuporaJive, lno.
APPENDlXA2

U.S_ NOx Conlrol Retrofil Projeels

NOx BACf Analysi, Slndy

-------------

rcduclions 1i'Led in Table A.2-2 for SCR systems are for dean reactor call1lysl and ideal operaling

condilions.

TABLE A.2-2 - Cyclone-Fired Boiler High-Dust5CR Installations

og gn yc

, _ GmoTIllnr nam<:plale "ling, March 2002 Energy Informalinn Administralion report

DOElElA_0095(2000). Ac[ual unil MW OUlPUI fllliug m.y be highc"T OT lowCT lhan namcplale_

}_ Bum' & McDooneli inlernal da",bas<:.

• _ " TC]lortccl 10 US EPA, available from ~lelr websi'o ,t hltp~/efpub.cpa.gov/gdmlindcx.cfm

, _ includes applicalion of,epal1l1ed overfiro nir rorcombuslion NOx control

, - curren! fuel believed 10 be a blend ofsubbin'/l1ioou.< and biluminous coal,

'_ NAO Ropublished da'" fromSCRemission testing fonnd on thcse unil,.

, , origiool ai, preheateIs were Nbular-rype; ohanged 10 rol'ry_type during SCR retrofit

• _ Design NOx removal efficienoy is higher, approll. 90%_

to _ elIITL'1lt fuel believed ro be subbiNminolls co,1

2003 07.<me Sea,nn

Unil AvcrageNOx

Si:r.e',M T"'lcd Onnel NO" Emi"ion Rale'

F,cilily' W Tesled Conlrol Emissiool~~le (lb/mmBlu)

Effi<iencv' (lblmmBlu }

Allen 1, 2, & J'~ 3JO c,_ 9LlINAD'188.7 0.07O!NAD'IO.0g8 0.088/0.07710.086

D.ldwin 1'·6 OO~ 82.9 0.0/2 0.2~8

- ---

B,ldwin 2'~ 60S' 8~.5 0.067 0.286

D'illy 8'"

'" NAD' NAO' 0.84

Cofro"" 1'"

'"' NAO' NAO' 0.114

Coffo<Tl2M on NAO' NAD' 0.120

- O,llman31&J2 '" NAn' NAD' 0.149/0.146

- - Kincaid I & 2'" 660' co. 89189 0.079/0_079 0.1811Ll98

M.,ion4 m 94.~ 0.067 0.252 - - M'rrim:Jok 1'~

'" 50.5' 0.148 0.15& - McrriJrulck 2

'" 5U' 0.155 0.171

MidiganCity 12,,10 '" 84.2 0.109 0.41 &

Now Matlrid I & 2~LO 600 e'. 87.4/88.1 0_149/0,147 0.JI91J.l/2

Parodi.. j & 2'~ 704 OR. 87_7187_7 0.102/0_101 0.124/0.113

P""di,c 3"· 1150 89.1 0.088 0.658

Sdtahfer J4"'· '" 83.5 0.106 0,478

, ri inal do,; fuel for all listed c -lone boilers was biruminou, coal

For Merrimack Unil I 's SCR, inlet (i.e. unconlrolled) NOx was 1_34 lblmmBtu, for a blend of

high sulfur bituminous and medium or low sulfur bilmninous coals, and requires year-round

SCR operation for compliance. The eal"lysl wus designed for 88_9% NOx removal efficienoy

Minnkol, Power Coopc,",ive, lnc. A2-7 Bum, & MoDonneil
NOx UACI' Analy>i, Sludy APPENDIX A2

U.S. NOx ('Alnlml Ren-or,l Projects

SHEeT/VB NON-CA1'ALYTICRElJUCJION

Pulvcrized cCl31_lired boilers

American Elcclrio Powor (AEP) Pulverizcv C,-"iI, odl·burncr, oppo.,ed wall-fired B&W hoiler

('.nrdilwl Urnl I 1%7 vinlHgc; Low NO, humor, inslalled m OctoheL' 199X

(,00 MW (nolnlllal) l:lnllinnl. Ohio

fuel Tech UTCH-b"sed SNCR iml"lle,1 in Oelober 1998.

Fuel Tcch, DOE, EPRI·membel' ulililics SNCR ,kTllOnSlr~llOnprojeot. Tested in Mal ch-April 1999,

clalmcd 65% reduclion with LNB, + SNCtt wi 5 ppm Nil, .,Iip, (rrom prc-LNB rtlrofi! baseline nf 1.20

Ib/mml:llu~) vown lu 0.52lblmmBlu "t 620 MW (100% MCR). SNCR rcdlJc~d NOx 31 % below LNl:l,

"Ionc (0.75 llJmmlllu baseline), "I 620 MWg (100% MCR), l~% I'.duclion al 75% MeR (~SO MWg),

and ~2% reducllOn al mllllm"m 10".1 (340 MWg, 55% MUt) ::'05% "mmonia Slipl"I, b"ming e,,"lom

b,lUmioou,oon1. UI'.a-lo-NOx NSR not Slalcv.

SOUTce: Fuel Tech cxperience li,1 dHled 11n12005; ('IICAC Whilc Paper, 1"12000 Fuel Tech leelmical

p"pcr, *Rl1cy Powcr (Babcock Powel' Inc.) cxpcri~"T1"~ li,1 811610L1.

Camlin" Powel' & LigllI (PlOgress Energy)

Asheville Unit I Pulverized Co"I, front wall lil'"d

200 MWe DB RJleyhoiler 19G4 vinLage, ea<lem billlminous coal, June 2000 SNCR slarrup

Fuel Tech commcrci"1 SNCR m,olnallOn ebnned 25% NOx reuuction fnmllow-NOx born" wlo OFA

baseli,,~ ot·0.58 Ib/mmllru (down to 0.4~ Ib/nnllBlu on SNCR "lone). Urca-Io-NOx NSR noj slaled.

(Also s~~ FLGR + SNCR inslallalion summ"rics for pulverize;u coallmileI'S).

Source: Fuel Tech experience !lst daled 1/28/2005.

C.",linn Power & I.ighl (Progres" Energy) Pul vorized Co"l, TangLTllially-fired

C"pe Fear Unil 5 19% vinlagc; e,,,I~m hilumino", coal

154 MW CE hoiler SNCR slanu]> i,,2002

Mobolee USA "Rol"mlx" amm"ni~J_h""',1 SNCll "yslcm injecI' "'I"COOS ammonia li,!ui,l inlo a high

velooily hOO<lcd sepal ared overfire "ir (1<01'A) .'yslem al the hoileL

CI'&L technical p"pL, c1"imedlo lower NOx from 0.28Ib/nunl:llu ba,dinc by ~J% 10 0.16lb/mmBllL m

2001 wilh 5 ppm NH, .,Iip 1ollowing the insl"lb(ion uf ROJ'A in 2000.

Overall reduclion 73% from foll"lo"v prc-ROFA baseline 0.60 Ib/nnnBlo lo O. 16 IblnunBlu''').

Mohotec daimed funher NOx reduclion wa.' I'0.,.,ihle by injecting urea in placc of ammonia, achieving

0.13 Ib/rnmBlu ;n,tc;Jd Ilf O. 18 IhlmmFllu, wmeh woulu be 54% ueorca.,e Ii om 0.23 Ib/mmBlu with

ROI'A alone, or ]X% overall dec""'I'e("I_ Ammonia·l0_NOx NSR not slaled.

Source: ("I CP&L 2002 Tcch~icnl paper; (]O) Mobolec 2003 lcchni<"lll pap".

Carolina Powcr & Lighl (Prow•." Enel'gy) Pulwrizcd Coal, Tangenti,lIy-lil'od

Cnp" I'oal' IInil {j [win-furnace (eight corner), 1958 vintage; C"stLTIl billlminous co,l

175 MW CE boiler SNCR slaTtup in 2001

Mobolce USA "Ro(amix" ammonia-based SNCR ~y,I"TIl, injeds aqueous ammonia liquid inlo n l,igl,

velocity boosled sep"mled ovcrfire a'r ("ROFA"') syslem at thc boiler.

CP&L technical paper claimed 10 lower NOx Irom 0_23 Ihlmmlltu haseline by 22% to 0.1 lb/mmFlru

wirh 5 ppm Nil, "lip following lhe insl"llation or IlOFA, "NCR in 200 1

1

1')_ Pccm,!alion slide g' aph

shows no reuuc(ion for Rol.mi. heYOlld ROFA alone al fulll",,{] NOx cmis.,ion rale of 0.23 IbinlIllBlu.

Ammonia_IO_NOx NSR nol "l"led.

Ovemll redllclion 67% fTorn full-load pre-ROI'A bnsc1ine 0.54 Iblmmlltu 10 0_18 IhlmmBllJ.

Moboleo daimed further NO, reduclion was po.,.,ible hy injecting urea in pl"ee of ammonia, ncllitving

0.10 Ib/mmBtll imlc",1 ofO. 18 lh/mmlllu, which would be 56% ue"ccasc from 0.1) lblnuuHlu With

ROFA alonc, or 8 I% ovcmll dccreascl'lI. Urea-Io-NOx NSR nol .'Laled.

Source: '''I CP&L 2002 Technicalpapel'; I") Mobolec 200) (echnie,,1 pap.I'_

Bnm, & McDonnell A2-10 MinnkOLa Power Coopcralivc, 1m.
APPENDIXA2

U.S. NO>: Cootrol Retrofil Projcct<

NOxBACf An"

TABLE A-3 - Low-Du~t Pulve~izcd Coal-Fi~ed Boile~ SCR Installations

M Donnell'mernal database.

'-Current fuel is caslern or midweslern birnminous coal, exccp,lla."""

J _ US EPA Dockel Oi\R-2002-OO7G~46Tccl1nical Suppon Documenl for DART NOx Limil' for

Elcctric Grnemling Unil' Excel Sp,."dsheCl 6115/2005, exccp' where nmed. Dale, in 0 "'" believed

10 be accumle bul have not bom conlinned.

• - TI,e three valuc'S aro "Pre_control ovemge", "2004 annual o~eTIlge". and "2003 ozone ,"",son "~erage"

NOx emi"inn TIlle" a, TCported to US EPA_ Prc_oontrol .nd yeOT 2004 .nnuol a~e"ge dato as shown

in US EPA DockeIOAR-2002-0076_0446 Technical Support Doeumenl for BART NO>< I.im;l' ror

Electric GeIleI1lling UnilS hcel SprcaJshee16l151I005. posted on lheir web.,ile:

IllIp:fldocket,epa.gov/edkpnbldoIEDKSlaffilemDelaiIYiew'lobjeeUd=090007d48084562b.

V.lues 'hoWII in porenlheses "re year 2003 .nnual ovemge where 2004 dal. is nol availabl". Y"",

2003 and 200] ozone ,coson data is .v",I.ble from the EPA's websile al

hlto:/ldjmb.epo.govlgdmlindex.cfm, indudes ,pplicolion ofsep.",ed overlIee air for combuslion NOx control where applieable_

, - Generator nameplale Taling. March 2002 Enorgy InroITUol;on Administrolion report DOElEIA0095(2000). AClUal uni' MW outpul TIlliog m.y be bigher or lower Ihon namcplolc.

• - This boiler has low-NO>: burners for ~ombllSlion control,.

7 Caroli"" Power & Lighl planl' list"" bere have Iwo boilers per unil, lolal namcplol< rnT Mayo i, 736

MW, Ro~boro i' 745 MW; emis'ion numbers.rc the aVallgo of both boile",.

• - Thi, hoiler has lo....-NOx bume,. and o~erf"" .ir for comb""ion controls.

, - Thi.' is prelimirullY dolO reponed to Ihe US EPA fo' 2004 ozone s"",,,m .~erage emi"'ion rdte.

,. _ Thi, boiler', ourrenl fuel is belle.ed '0 be subbitnminous coal.

" - Mercer boil.,,, listed have low-<iust SCR WiIh nue g"-' rehear. Unil size is approximalc, 0"1 namepl.le.

NIA c<Jmplere 2004 ozone ,e"so" dala is nol .vailoble, and 2003 OWoe seaSOn d.l. is not TCproscnlati~e

of lhe po'I-SCR inSlaHalion emis'i"n rate.

'CR Unil Si,e',

Operalor/Facility' Slarlup i\verageNOx Emi'.,ion MW

Dale" R.les· (lhlmmB'n\

AEPICo,d'lUlI Uoit 3' 5101/03 0.74/0.34/0.1J5 ",

Carolioa P&lJMayu Unit I' -/(0.J6)/N/A 368 x 2

Carolioa P&URoxbolO UniI4'" 5107fOI ll-57 10.26 10.081 372 x 2

CinergylEaSl Bend Uoill 4/01102 -1(0,28)10.067 "'

C<m,lcll.lionIBrnndon Sho",s Unit I' (2001) 0.4710.33 10.126 '"' , --- ConstellalioniBraodon Sho"" Unit2' (2000). 0.45 / 03 I I 0.094

'"'

Daylon P&UKiHen Slalio" Unil2 IIIOIIOJ _/(OAR)/0.06 ...

Dyn,gy Midwesl GeniHavana Unil 6'" (2000) 0.46 10.20 / O. 102 '" , - PSEG Power LLC IMercerUnir j II (2005) -/(0.G3)/NIA '"

PSEG Power liC / Merce' Unil2" (2004) _/(Q_76)IN/A ''0

Bnm.'& ,

MintlkOl' Power Coupcralivc, Inc. 1\2_9 DLmIS & McDoJUldl
NOx DACr Analy';' Study APpENLllX AZ

ns. NOK Cootrol Rellofll Projecls

SELECTIVE NON-CA1'ALYl1CRElJUCHON

I'ulvcri:wd coal fired boilers

Anll'Tican Electric Power (AEP) Pulverized Coal, cell-burner, opposed wall-fired B&W boiler

Cardinal Unil I 1%7 vinlngc; Low NO, burner, installed in (klobcr 1998

600 MW ("omim,l) Brillianl, Ohio

F"el Tech urea-hased SNCR i"'lalled il\ Oclober 1998.

Fuel Tech, DOE, EI'JU-member ulilil,es SNCR demunslmlion project. Tesled in March_April 1999,

el"imcd 65% reductJOn wilh I.NA, + SNCR wI 5 ppm Nil] slip, (Imm pre-LNB relrofil baseline of 1.20

Ib/mmBl\l~) dawu to 0.52 Iblmmlltu at 620 MW (100% Ml'Il). SNCR ,educed NO" 31% below LNB,

alone (0.75 IblrnmBI" b",eline),"1 020 MWg (100% MCR). 3~'10 reJ\lclion al 75% MCR (~50 MWg),

~nd ~2% Tl.,<Juelion al m",,,,mm load (3~0 MWg, 55% MCR) :0% ammonia "lil,I"I, burning easlern

bituminous coaL Urea·lo-NOx NSR not slated.

SOLLrC~; F\lcl Tceh experience lisl dared 112~/2005; (11leAC While Paper, {I'lJ 2000 fucl Y,'ch lcchnic"1

paper, *Riley Power (Babwck 1'owcr Inc.) expel'iel\cc hSI 8/16104.

C"rolina Powel' & l.ig"l (Prol,'fCS> Enel'l,'Y)

A,heville Unil 1 Pulverized Coal, fronl wall fired

200 MWe on RJ1ey hoib 1964 vinlage, easlern bimrnim'LlI cuul, J unc 2000 SNCR slart"!,

Fuel Troch eummercml SNCR installatiOll chlimcd25% NUx reduclion Imm ]ow-NOx burner w/o OFA

baseline ofO.5~ Ib/mmRl" (down lo 0.44 Ib/rnmlltu 01\ SNCR alone). Urc"-lo-NOx NSR "01 ."laled.

(Also "e~ FLGR + SNell mslallation summaries fur pulverized coal bOIlers).

Source: fuel Teclo experience il,1 daled 1/28/1005_

Carolina Power & Light (Progress Enel'gy) Pulverized Coal, "j'angenlially-lir~d

Cape T'c"r Unit 5 195(, vjntage; eOSlern hil"minou" coal

15~ MW CE boikl' SNCR slarlup in 1{)02

Moholee USA "RotamJx" ammonia.hase<! SNCll syslem injecIS aque(lu.' ammonia liquid inlo a high

velucity hoo.'ted ,epawlcd uVl'Tfin; "ir (ROFA) sy.'lem al thc builer.

CP&T. Icchnieal paper claimed 10 lower NOx from 0.2H Ib/mmlltu ha"eli"e by ~3% lo 0.16 Ib/mmlltu in

2002 with 5 ppm NH, slip following Ihc in"lallalioLl ofROI'A in 2000.

Overall reduclion 73% li'om rull_Iond pre·ROFA baseline 0.60 lb/mmBlu 10 O.161b/mmBtu!"I_

Mol:>olcc clajmed Ii.mher NOx rcducllOn was possible hy mjecring urea in pIucc of ammonia, achicving

0.13 Ib!LllJnfllu in,I"",1 ofO.I~ IblmmBlu, w"ich wouI,1 be 54% dec=se from 0.28 Ib/mmBlu wilh

ROFA "lone, 01' 78% overall decl'easell'J. Ammonia-lo-NOx NSR nOI slaled_

Source: {'"J CP&L 2002 Technical paper; ("J Mobotee 2003 leehnical paper.

Carolina Power & I,ighl (Prob'[CSS linergy) Pulvcri~--,,<! CO"!, T"ngcnli"Hy-IITcd

Cape Fcur Unil 6 twin-Iumaee (ei~ht comer), 195~ vinl.'lge; ea'lcm biluminou" eoal

175 MW CE boiler SNCR slllrtup in 2001

Mobutee USA "Rolamix" ammonia-based SNCR sy'lem, i,~eclS "'Iuco", ;llnrnonia liquid inlO" high

velocily bOOSlcd scp"rnled overfire air ("ROFA'') syslem "I Ihe boiler.

CP&L technical paper doimed 10 lowcr NOx ITom 0_23 IbfmmBlu b"selim' by 22% 10 0. ISlb/mmBm

wilh 5 ppm NH, slip fallowing the inSlallaliun of ROI'A+3NClt in 200 I{'"). Pn:s('ntalion slide graph

shows "'0 rodu"lion for Ilolamix beyond ROFA Hlune al full lo"d NOx emi""Oll rolc of0.23 IblmmBlu.

i\mmol1ia-to-NO~ NSR nol 'I;lled.

Ove,all reduclion 67% from lull-load I're-ROl'A b"seline 0.54 IhIonmBru 10 0.18Ib/rnmBlu.

Mobolec claJmed furth'T NOx reduclion was [Jo%iblc by inJ"eling urea in place 01" ammunia, achieving

0.10 lblmrnBlu lJl.,tead ol"O.181l>!mrnBlu, which would ho 56% "CC"'"'" from 0.23 Ib/mlnBI" wllh

ROI'A ~Ion', or 81 % overall decrease("). Urea-to-N()X NSR nol Slale".

Source: ("I CP&J. 2002 Tc"hnical paper: 1"1 Mobol""C 2003 Icchnical paper.

13m", & MoDonneli A2-1U Mmnko" Power Cuup:ralivc. lnc.
APPENDIXA2

u.s. NOx Control Rotrofit PwjeoL,

NOxIlACf Au"iysisSludy

Pulverized Co~], Tangentially-fire<!,

1%0 vintage; slarmp prior to 2000

SELECT] JlE NON-CA TAL YUC REDUCTION conrilluetl

PUlverized coal-fired boilers

Cinergy (fonnerly Cincinnali G&E)

Miami I'ort Unil6 (Ohio)

163 MW CE boiler

['uel Tech urca-b"sed SNCR system, claimed to lower NO" by 35% [rom 0_55 IblrnmBlU

haselinclll.(assume ea'tern biluminou< coal). Urea-lo-NOx NSR not slaled.

Source: Fuel Tech experience list daled 1/28/2005, (I) ICAC White Paper.

Conccliv (fonnerly Delmarva Power & Lighl)

Edgemoor Unit 3 Pulv~rizcd Coal, Tangenlially-fired, 1954 vinlage

84 MW CE boiler mid·Mareh 1996 startup; (assume easlern biluminous coal)

H~mon Research-Collrcll supplied a ur~.,,-b"'ed SNCR system_ IIRC cluimcd 35% NOx rcduelion wilh

less lhan 10 ppm ammonia slip. Urca_w_NOx NSR not stated.

Anolher source shows n )0% reduclion [rom 0.541blmmiltu basclineill.

Sourcc: Hamon experience list (not listed by Fuel Teoh); (l) rCAC While Pupcr_

Concetiv (formerly Delmarv~ Power & Light) PulvcTized Coal

fudian River Unils 3 & 4 (lVIillsboro, DE) Unil3 is front wall-fired, 1974 vinl"ge

178MW and 440 MW Unit 4 is turbo-fired opposed-wall, 1980 vinlage

B&W, DB Riley boilers Spring 2000 startup (,,"stem biluminous coal)

Hamon Rcsearch-Coltrcl! supplied a ur,,"-based SNCR syslem (nOllisted by Fuel Tech) on bolh units.

HRC claim~d 35% NOx reduclion wllh less 'han 5 ppm ammonia ,·Iip. Urea-lo-NCh NSRnol ",'led.

An REI 1999 leclmical pap~T shows a pre-SNCR baseline 0[0-37 and 0.44 Ib/mmBtu, respectively_ (2<1)

Another source lisled lhese units uS having a pre--contro1 NOx b"scline of 0_97 and 0.57 IblmmBlu, and

20J)4 po,t-SNCR slmtllp average of 0.32 und 0.33 IblmmBru, respeelively. (121

Soul'ce: Hamun uxperience list (not "Sled by Fuel Tech); ('") ItEr 1999 technical p"P"r;

I"!JJS EPA Docket OAR_2002_0076--0446 Excel Spre"dshecl6!1512005.

Dominion Generalion (Virginia E&I' Co.) Pulverized Coal, Tangentially-fired

Oover Stalion, Unils I & 2 (VA) ABIl/CE boilers, 1995, 1996 vintalle

2" 465 MW (,,"slem biluminous coal)

Urea-based SNCR (Fuel Tech syslem) 1995, 1996 startup (inilial commercial)

Fuel Tech claimed NO" reduced by 25% from 0.J2 Ib/mmBlU b...,eJine (10 0.24 lblmmBtu).

Source: Fuel T""h experience li,1 (bled 1/28/1005. Urea-lo-NO" NSR nol slalcd.

Dyne£:)' Midwesl Gen~'rnlion (formerly Ulinois Power) Pulverized C.oal, Tangentially-fired

Vermillion Stalion, Unil I 1955 vinlage

82 MW CE boiler, bituminous Illinois CQJl

Moholeo USA uROlamix" urea-based SNCR System wilh rotaling opposed fired air(ROFA).

Mobol~c 2004 lechnical paper claimed to lower NOx-by 55% [rom 0_211b/rnmBw baseline 10 0.10

IblmmBtu in April 2004 Wilh urea-based ROlami" SNCR and < 5 ppm CO. NH, slip nOl menlioned.

Overall reduction 83% Irom fuJl-luad pre-ROI'A baseline 0.58 IblrnmBlu to 0_10 IblmmBlu I"). Urca-loNOx NSR not staled.

Souroe: 1")Moboloe 2004 ledmical pap<.1".

Mintlkoto Power Coopmll;ve, Ino. A2_tt Burns & McDonnell
NOx BIICT Analysis Siudy IIPPENDIX A2

U,S. NOx Cunlrol RclroJil Projecl'

Source: fuel Tech experience li-,t daled 1/28/2005; al"" listc":! m (L)ICAC Whilc p"pc,-. (Also sec

I'LGR+SNCR insl"lblion sllmmaries for pulverized coal hOllers)

SHl.HCTlVE NON-CATALYTIC REDUC110NCOII/ilmed

l'ul\'crizcd coal-lind hniler.

Relianl J7.1Lergy ([omK"Tly GPU Gmcu) Pulverized Cool

(formerly Silhe, I;,rmerly Pelleleo) T,mgenliJlly-fired

Scwanl # IS (PA) mi<l_1 ~90', SNCR Slarlup

UniL, & 5 easlern bilHmiJlOus co"1

62 & 156 MW CE boiler.; I9~O & 1"57 vll1[Jge

1]ren.h",ed SNCR (fud Teoh ,yslem). bier inslalled all in-ducl SCR 10 reduce NH, .,Iip.

Fuel Tech claimed to lower NOx 35% [0, SNCR only (55% for combined SNClUSCR rrom 0.78

IhhnmBlu b"sdm~). \J()iler, h"ve since been demol i-'hed and r<:pl,!Cc"(1 wilh CI'Tl&. llr"'-lo-NO" NSR nol

.'l"lled_

Source: Fuel Tcch cxpGr:icnc~Jisl dJled Il2g1200S, (l)JCAC Wh,IJ,: Pupee.

Roches!,,- Gns & Eleclric Pulveri7ed Coni, Tnngenlinlly.fired

Russell Slation, Umls 1-4 (NY) 1948, 1950, 1953, 1957 vml"ge

1 x 50 MW, 2 x 65 MW, 1 x 85 MW CE boilers ea.,lem b'luminous cool

Urea-based SNCR (Fuel Tech system) SNC'R sl"rtllp pnor 10 2000

Vendor claimed to lower NOx by J5-27.5% from 0.28 - 0.42 Ib/lllmlllu baseline.'. UreJ-Io-NOx NSR not

sbled.

Snuree; l'ue! Tceh "xp"rieTl"~ lisl <bled 1128/2005.

HYD/WCARBUN-ENHANCED AMMONIA SNCR (NOxSl"r"~

Pulverized coal_fired boil.~.,

Tennc"te VaJky Aulhorily ('JV1\) Pulve, ized Coal [wi"-ILJ) nnee. LJngenllally-fi,ed,

Kingston Power StatlOll (TN) 1955 \'inl"ge caslern b'luminouo ern,l

Uml9, 200 MW" CE hoiler NOxSLJrB ' ,(urlup Junuacy 2001

Demonm:ation of NOxSlarTM hydroo:arbon'''nh,me"r1 umrnoniJ-based SNCll i"'l"llalion.

M'IS\li B"heuck e!mmod 68% NOx reduclion from baseline orO.55 Jb/mmBlu down In 0.17 lblmmBlu

with boosled OFA nnd NOxSlnr'M wilh <: 5 ppm ammonia ,lip; NOxSI"r'>' "Jonc TC"(lu"c<1 NOx hy

53%(»'; boo,led Of'A only T"duted NOx from 0.55 l() OA5 IblmmBlU (18% Leduclion). Ammoni,-IO_

NO" NSll not slJted.

TVA', w"b,il" ",porlc,1 Ih'l "un earlier version of NOxStar wos inSlalled ol KingSlon 1'o."LI Plonl Unit

in 2002 wilh mixed resulls. NO:< reduolions wer~ ndll~v"d, blll Ihe boiler was dJmagcd"

(l'ITp:l/www.t"'_gov/en"ironmenli"'pulm'cnvn:porlsJ"erI2003Ienv enml'lianee_htm)

Source: Ill) Milsui B:ab"oek Technic"1 parer, Ocloher 2003. .

Tennes,;ee Valley Authority (IV'A) Pulverized Co"l, wall-fired

Colherl 3("lion (AL) 1955 vinLag"

Unil~, 192 MWe twin-furnJce B&W lmiler wI FGR ~.,.slcm bilumll10us ooal

Finl eomrncn;iol mslalblion of NOxStarTM hydmoarlmrJ'''nhun"ed arnrnoni"-h"sed 3NCR Icchn()logy_

Mil~ui B"b<:od( showell 80% NOx reullction from bJselllle 0[050 10 0.10 JhlmmRlu; Il.,ing < 0_1% of

10lJI boiler he"1 inpul for propane input and 1% O[lOI.1 SI,-Jm now generaled in the boiler for bnce

ooolingl1J ); 2004 SNCR sy'tem SIUrlllp. Anunonia-Io-NO:< NSR 001 slated.

Source: (LJ) Milsui Bahcock 2004 Techn ical pap''-.

Burns & MoDonnoll 112_14 Mi"tlkorn Power f'oopeJaIJYc, Ino.
APPENDlXA2

US. NO" Control Retmlit Projecls

NOx BACT Anal)"i, Study

RIM claimed 50% rcdnclion from 050 IbfmmB~u pre_SNCR b.selinc to 0.251bIrmnBlu for SNCR coalfiriog operation; NOx baseline 0.82 lhJmmBlu prior 10 R]M's LNB modificalions installed in 1994, 1992,

& 1994 (39% reduction); Urea-m-NO" NSR nol slale<!.

Fuol Toch c1.imou30% NOx reduction for SNCR from basoline of 153 ppm firing 116 fud oil on Unils 4

&60nly.

Source: RlM experien"~ list, Fuel Tech expcrien"~lisl ualed I/2S/1005.

SELEC11V£ NON-CATAI.YJ1C REDUCTION ~OJJlirllled

Pulverized "oal_fired boiler"

Owensboro Municipal Ulililies (KY) Pulveri""d Coal, Tangenlially-fired,

Elm"" Smilh Unil2 1974 vintage

300 MW CE boil"" eastern hituminous coal

Hamon Re,;eareh-Cotlrcll supplied an ammonia-based SNCR syslem but slalcd noel'Lms for NO>;

reduction; (this proj""~ is not listed in ICAC Whilo Paperl'J). Ammonia-to-NO>: NSR not sl"led.

Source: Hamon experience lisL

PECO Energy (formerly Philadelphia Electric Company)

Crumby Unil I Pulverized Co"l, frOnl w.ll-fired divid"d furnace

160 MWe B&W boil<:r 1954 vintage eaSICTIl biluminous coal

fUM inslalkd. Fuel Tech u",~·based SNCR wilh low NO" burncr modificalions & OFA in 1999, June

1999 startup.

)L!M_claj.n:te.!l_~'!o SNCR NO>; reduclion from b.seline ofO.J5Ib/mmBtu, down 10 0.25 lb/mmBlu with

urea NSR = 0.8; RJM pro';;ided 'b~~-~~'':;:;~~liii"alioosOfB&--W-'XCL fo\v-NOx b\imers'i,;slalled 'inT9iM"'+

OFA; thio reduced NOx from 0.50 10 0.35 Ib/mmBlu (:l0% reduclion) without SNCR. Urea-lo-NOx NSR

nol staled.

Source: RlM experience lis~; lllrCAC While Paper.

Exdon (formerly PECO EncTgy/ Pennsylv"nia Electric Comp"ny)

Eddyslone Units 1 & 2 Pulverizecl Co~l Tanllen~ially-fired,

318, 33J MW eaoh CE builers 1999 SNCR slartup, eastern biluminous OlIal

Fuel Tech claimed 30% NOx reduction from bnselino ofG.26 Ib/mmBlu.

Source: Fuel Tech experience list daled l/l!lf20G5.

1954 vinlage

Public Servioe Enterprise Group (PSEG) Power LLC [formcTly PUblic Service Electric & Gas ofNew

Jersey (PSE&G)]

Huuson SL:llioll, Unit 2 Pulverized Coal, opposoo-Wlll1-fired, 1968 vinlage

660 MWe Fosl~T Wheeler hoilereastern bituminous coal March 1999 smrtup

Fuel Tech urea-hased commcrcial SNCR installalion claimed 25% (initial)NO" reduclion for SNCR

ulone from baseline ofO.651bfmmBlu (down to 0,49IbfmmBlu). Urea-lo-NO" NSR not staled.

Source: F\lcl Tech experience lisl dated 1/1&12005. also lis~ed in (I)ICAC While P.per. (Also sec

FLGR+SNCR inslallation summaries for pulverized co.1 boilers).

Publi" Service Enlerprisc Group (pSEG) Power LLC [formcTly PUblic Service Electric & Gas ofNew

Jersey (PSE&G)]

Mereer Stalion (2) lwin·fumaoe builers, 320 MWe each, Oil Riley lurbo-iired

Unit I and Unit 2 front w.1l1'C, we~-bouom (slagging ash) eastern bituminous eo~l

Furnace 1111 & #12 1960 vinl~ge April 1999 slartup

Furnace #11 & 22 1961 vinlage May 1999 slanup

Fuol Tech urea-based OlImmercial SNCR inslall"llon claimed 30-35% NO" reduction from baseline 0[2.0

lb/mmBlu on SNCR alone, down 10 1.4 lb/mmlllu. Urea-to-NOx NSR nol slaled.

Minnko" Powor C""pe,"~jve, Inc. A2_13 BunlS & MoDonndl
;"'0,, BAG Analysis :;lmly APPENDlXA2

U.S. NOx Control ReTrofil Projocl'

Souroe: Fllcl Tech experience list dalcd ]/2812005; al,o liHted III (JllCAC Wh,lc Papcr. (Also see

FLGR-I SNCR in:>I"Uation summaries fm I'ulvcrio<cd coal boiler.,)

SELEC11VE NON-CATALYTICRElJUC110N ~(JIIli/1l/~d

Pulnrllell ro~l-Iired boiler.'

Reliant ELlerJ',Y (I", rnedy GPU Genco) Pulv~Tized (:0,1

(fonnedy Sllbe, formerly Penclcc) TnLlgcnli<llly-iired

Seward # 15 (PA) mld-1990', SNCR st.rI"p

UnilR 4 & 5 cmlcm birum1!lou, co.1

62 & 156MW CE boilers 1950 & 1957 vinl"gc

lJrea-ba.'ed SNCR (Fuel Tcch syslem), later iTls"'lkd "n in--duct SCR 10 reduce NH, slip.

Fuel Tech claimed to lower NOx 35% f"r SNCR only (55% for combined SNCRISCR from 0.7R

Iblmm!l lu h"scline). BoilcTs have since 11een demolished <lnd Iel'lace<1 Wilb eFR&. lJ"',·lo-NOx NSR 1\01

sl"lcd.

Source, Fuel Tech expcTic'1lce Jist dated 1/2~/2005, (I)ICAC While Paper.

RochesIer Gas & Eleclrie Pulverized Coal, Tangenlially_lJred

Ros.scll Sialion, Unils 1--4 (NY) 194R. I950, I~53, 1957 virltar,e

1 x 50 MW, 2:x 65 MW, 1 x 85 MW CE boilers caslern himminous c",,1

U"'<l-b,,,"'{1 SNCR O'uel Tech sy.<tem) SNCR .'IOrl,'P prior 10 2000

Vendor clalmed [0 lowe, NO. by 15-27.5% from 0.28 - 0.42 IbhnmBlu ba'elJlles_ Urea-lo-NOx NSR nol

slale,!.

Source: fuel Tech ""po,ienec li,1 daled 1/2812005.

TTYDROCARlJON-!:.JVJ-JANCElJ AMMONIA SNCR (NOx.'illlr""')

Pulvcrized coal_fired hnil..-s

Tenne..<3ee Volley A\Jlhonly (TVA) P"lverized CoaIIWJIl-lum<lce, Langenll.lly_fired,

King'lon Power Slalion (TN) 1955 vmlngo cast~"Tll bltllminolls coal

IJmt 9, 200 MWe CF bOlkr NOxSla,TM SLarilll' Jarluary 2002

Demonslmlion of NOxSlarTM hydr'Ooorbon-enhal1ced amrnOTli~·bused SNert inslallation.

Mil"ui Babcock cl.imod 68% NOx reduciiOLI from bllscline ofO.5511>!mrnBlu down 10 0.17lblmmlJlu

Wilh boo'lcd O}-A and NOxSlarTM Wilh <;; ppm ammoma slip; NOxSl,n'J1< "lone rcduccd NOx by

53%''''1; boosled OFA only reduce,l NOx from 0.55 la 0.45 lblmmUlu (1 8% ,educIion). Alllmonia-loNO~ NSR nol '~IK..J.

IVA', web,ite reported lhal "un e<lrlier versioJl ofNOxSlar WaR inslalled aI Kin!}'torl I'o"il Pbnl Unit 9

in 2002 wilh mixed resulls. NOx reduolions wcre achieved, bUllhe boilor was dam<lged"

(hltp;/Iw\V\V.tva. govIenvironmCr; lIrcpo Iralcnvreport,.,raed20031env_campIiance.h tm)

Srm,ce: (22) Mils", B<lbcoek Teclmical papcr, Oolobcr 2003.

T~'1lnes""e Valley AUlhol'Jty (TVA) Pulvenzcd Coal. wall-fired

Colbert Sliltion (AL) 1955 vinLage

Unil4, 192 MWe twin-furnace Il&W boilcT w/.F(jRea;aenl biluminous coal

Fir<1 commerciul inSlall<llion of NOxStarTM hydroeurbon--enhanced ~mmoni~-bascd SNCR lcclmolo!lY.

Mil"ui Ilabcock "howed 80% NOx reduction limn l,asclinc of0.50 to 0_10 lhlmmBru; llsing < 0.1% of

lO1il1 boilc, hC"1 input for propane inllOt nod 1% of lola1srenm now g~-nc"'te<1 in Ihe boiler for lance

eooling1"); 2004 SNCR syslem slartup. Ammonia-lo_NO" NSR no! "lated.

Source; (1l) Milsui Babcock 2004 Technical pap<'r.

Bum., & MeDonnel1 A2-l4 MmnkolO Pnwer Coo!"'rdlive, Inc,
APPENDIXA2

U.S_ NO" Control Retrofil Projects

Pulverized Co~l, oppo<ed wall-fired

cell-bumer, 1969 & 1972 vintage

eastern bi tuminous "cal

REBURN- GAS, CONJlENTIONAL

Pulverized coal fired boilers

Allegheny Power (formerly West Penm,ylv:mia Power)

Halfield's Ferry Slation

Unils 2 & 3, 600 MW (nominal) encb (B&W boilers)

GE-EER Gas Reburn; 1999 sLartup (Unil 2) & 2003 (Unil J)

GE-EER Low NO" burners, boosted OFA, gas reburn system.

(jE-EER clnimed lO lower NO" up lO 67% from b"scJine of 0.60 Ib/mmBtu 10 0_20 lbfnnnBtu at full load

Wilh relmm operation on Unil2, 68% from 0.62lb/mmBln to 0.20 IbfmmBtu on Unit 3. No claims of

percent r"bum fuel included.

GE_EER teclmicaJ paper shows appro". 35% NO>: reduotion at GOO MW load mth LNB + OVA wlo

reburn fuel, 'md nn addilional 50% reduction lo 0.20 lblmmBtu with rebtlrn fuell")_

B&W added 20 OFA porls in 1994 per B&W's experienoe list. No NOx reduction claims. Source: S~l'l.

2005 GE-EER cxpcrience li'l: (!OJ OE-EER 2004 Te"hnical puper. Unit 2 and Unil 3 li,ted in l'IDOE_

NEIL Scorecard on Reburning 61112004 (from 2004 Reburn Cooference).

REBURN- GAS, CONVENTIONAL co"ti"ued

Pulverized coal-fired boiler.•)

Conecliv (fonnerly Dclmorva Power & Light) Pulverized ConI, Tnngemially-fired

Edgemoor Unit4 1966 vintage, eastern bituminous conI

160 MW CE boikT 1999 slarlup

. --·GE-tiliR-OasRebunJ project a<Jili,d gas supply pijJm~r;ietef1n-g;lfatiger-s;-supports;-reburtfiuj eo till;;""<iJidn

cooling air piping; OFA duolwork, injection nozzles and wall ports, field inslrumenlmion. No FGR Or

OFA booster fans_

Vendor claimed to lower NOx up to 48% from baseline of0.32 IbJmmBtu to 0.16IblmmBlu) at fu1110ad

wjth rcbum operation. No cluims ofpore""l rcbum fuel included.

GE-EER technical p"per shows approx_ J2% NOx reduotion for gas rcbum with 4-mill operalion at 160

MW lood from 0_3 I IbfmmBlu LNB + OFA buseline wlo rebum fuel (down to 0.21 IblmmBtu), and 48%

NOx reduction for !,,,,s rebum Wilh 3-mill operation, to 0.16 IbfmmBtu (2<J.

Source: SepL 2005 OE-EER e"penenee lisl;l2') GE_EER 2004 TeclmiClll paper_ Listed in "IDDE_NETL

Soorecard on Reburning 6/1/2004 (from 2004 Reburn Conference)

Dynegy (fonnerly Illinois Power) Pulverized Coal, Taugcnli~lly-lired

Hennepin Unil I 1966 vintage

71 MW CE boikr eastern bituminou" co"l

GE-EER Gus Rchurn, 1990 startup (not currently opcIUling); GE-EER Orirnulsion Rebum, 1997.

D9E Clean Coal dcmonstr.t;on projeol (included sorhont injection).

Vendor cloimed gas rehum wi OFA lowered NO" up to 67% from buseline of 0.75 IblnnnBtu to 0.25

Ib/mmBllI) at fuJI load; 65%reduclion from baseline of0.75 lbfrnmBtu down to O.261blmmBlu with

subsequent Orimulsion rebum operation.

GE-EER 2004 technical paper shows 18% gas reburn fuel yielded minimum NO" emissions('J.

Another lechnical p3per showed this 80 MW US DOE Clean Coal demonstration project in January 1991-

J"nu~ry 1993 lowered NOx by 67% from O.75lb/mmBtu baseline (lO 0_25 lblmmBln) with 18 percent

rebum [uell5).

Source: Sept. 2005 OE.EER experience list; (6) GE-EER 2004 Technical p3per; l')DOE_NETL 2004

Rcburn Conlerenee leolmical pUp<.', and DOE-NETL Scorecard On Rebuming 6/1/2004 (from 2004

Reburn Conference). (Also see Conventional Oil reburn installation summaries for pulvlTized cooI

boilers).

Minnkol. Power Cooperalive, tne. A2-1S Dum' & MoDonnell
NOx BALI' Analy.i, Sludy APPENDIX A2

I I-S. NOx CDnlrol Rclrolil Projecls

RJWURN . COAL, MICRONIZED, CONVENTJ()NAL comilllled

Pulverized cool_fired boil.r..

E ON US Boldin!!:> (fonnerly !'ouj,vJlle Ga" ond Elechic)

R.I). Gre~n Slnl ,on Units I & 2 (KY) wall-flred, plLlverized coal, vinlagc unknown

293 MWe, 2 boilers ~:"lern billlminous coal

GE-EER cuul rehurn 'yst"m Sl0l1UP dale." 2003 & 2002, rcspeclively

Vcndor doimed lo lower NOx up lo 57'Y, I,orn hasellllc orOA5 lb/mmBlu 10 0.20 Ib/nllnBllL at full load

Wilh rehum O]JLTdlion.

Rchorn 'yslcm li'ICt! on EPA's "Scorecard un Rchominr, 611/2004" shows NO~ lowcred hy 44% [;-om

bo",linc of OA5 lhfmmllllL down 10 0.25 Ihlmmllm (Wllh unknown rebnrn fnel inpnl('~.

Anolher lcclmic:ll p"per ~howe<1 ba,cline NOx wilh exi:;ting 10w_NO~ bllmclO wu:; 0.45 IhfmmBlu, tl11l1

reduced NOx em'.«ion 40% [0 0.27 Ihimmlllll Wilh OFA, and furlh~r reduced NOx emis.,ions 21% down

to 0.21 Ih1nnnl:llu Wilh the cual rcbum syslem in opcr;Lliun".

Source; I') DOE-NETt Scoreeard On Reburning 611!200~ (Jiom 200~ Reburn Conference):

1"1 GE Energy 2004 Technical paper, and (20) M:lrch 2004 Mudem Pow"r Syslcms issu~.

Cheng Loong (not iu Unilcd Slale,)

IInil I;' I, 250 MWe wall-fired, bi(uminou, pulverized coal, vinlage & mfr unlmo"",,

GE-EER coal rebllrn syslem 2000 Slartup (s(ill operaling)

Source, CoE-EER expel'ience li"t

VemJor cbimed 10 lower NOx ~4% from b~selin~ 0,45 IhlmmRtu 10 0.25 lillmmnln) al lull load with

OVA alone: further ,educed NOx 2~% 10 0.1 Ihfmnillill. for 60% ovcmll redllcllOn. Recenl (2004) Jata

sbows NOx ,lown 10 0.14 Ib/mmB III (69% Qvcrdll) wilh up lO 30 perOenll'elmm liJd").

Sonree; (") Col' Enel'gy 2004 Teohnical paper: GE-EER experiencc lisL Lisled in (» DUE-NIo'l'L Scorecard

on Reburning 6/1/2004 (from 2004 Reburn Confcrencc).

REBURN - GAS, CONVEN110NAL 'v SNeR

1'"lvcrlz,'d cual_lIre,] boilers)

NRG Somer"et Pulverized Coal, T"ngcnli""y-fircrl, vinlage

Unil6 Builer (NY) GE_EER CO<lvenlional Gas Rebllm,

120 MW CE hoiler Fuel 'feeh SNCR, 2003 'lartup

Rehum vendOL claimed to lower NOx 55% Irom 0,45 lb/mnillill baseline 10 0,20 Ib/mmBlu"1 fuJlloaJ

w,lh rchum opm'lion burning VC'Tlcwd:m c()ul. Thc SNCR 'y.'tem lurlher redu~ed NOx emi"lon, 45%

,10wn 100.11 IhlmmRlU, ior an ove",]] redllclion 01'77%.('").

SOUlce: Sep!. 2005 GE Encrgy c~pericncc IoSl; (10) Murch 2004 Modem Pow~r SyolenLS Jssue.

REBURN - FUHL LEAN lJ"AS REBURN (FLGR)

1'"1,,,'~jzed eoal_li~ed boile~.,

Dnke Power CompJTly langentially-fired, pulvcriv.:<J coal

Rivc"Thcnd Unil 7 ea"lern bilUminou" coal 1954 vintage

140 MWe, CE boiler 1998 FLGll slartup:gas rebum rlttOmmioslOnerl sincc lhen

Previously in,Lalied ARB/CE's I.ow NOx Concentric Firing System (LNCF:>-I) Wilh Close-Collpled

O"erfir~ Air (CCOFA); (pre-mod NUx'l combustion mods dalc nOl known).

Commercial FLGR inRlallalion daimed34% NOx re<luc(]on from fulJ-Jo:ld b.sdinc ufOA2 IbfmmBlu

do\\'Tl III 0.29 IbfmmBtn w/lhe comhu.<lion modJllca(]ons and l'LGR gas rebum fuel at 7% of lolaI boiler

heal mpuL CO emi"ion, W~"TC above 1000 ppm cOITeclccllo 3% 0,.1"1

V''Tl<Jur claimed lO lower NOx 57% from OA71b/mrnlltn ha.,eline 10 0.20 Ih/mmllln) al rullioad Wilh

seraraled OFA alonc; furlhcrrcduced NOx ~5'1'0 10 0.11 IblnunBlu wilh 10w"NOx bUm~T", OFA, gas

[cburn, and SNCR, lor 77% over.1I rccluction; nu c]UlIT'" lor amon", or rehlll n I"el{"'.

Bum> & McDonnell i\2·1~ Mumkul. Puwer Cuoperdlivc. Inc.
APPENDIXA2

U.S_ NO" CoolfOl Retrofil Projects

NO"DACf An,lysis Sludy

REBURN- OIL, CONVENTIONAL

Pulverized ooal:fired boilers

Dynegy (formerly Illioois Power) Pulveriz<:d Coal, T3ngen~ally-fircd

Hennepin Unit 1 1966 vintage, c~l'1ern biluminous coal

71 MW CE boiler 1997 slartup

GE-EER Orimulsion Rebum syslem wi OFA, c1.ime<1 arimulsion reburn lowered NOx up La 65% from

baseline of0.75 lbimmllLu to 0.26 lblmmBlu al fun load wilh Orimulsion reburn opera lion (m3talJed Jner

gas reburn WJ~ demon.<lraled in early 1990's). No clJims for percelll reburn fuel induded_

GE-EER 2004 leohnioal paper shows 60% reduclion wilh ~ubs<XJuenl 06mulsion rehum 1').

Source: GE-EER experienoe lisl; (') GE-EER 2004 Teohnical pJper. Orimulsion not mentioned in (5)

DOE-NETL 2004 Rob"rn Conrerence tedmic"1 pupcr or DOE-NETL Scorecard 00 Reburning 6/1/2004

(from 2004 Rcburn Conference). (Also ~~"C Conventional G", Rebum iostallalion summarie, for

pulvcrin,d coal boilers).

New Brunswick Power

Coleson Cove, Bunker C10rimulsion-firecl, oppo3ed-wall

S1. John, New BrunswIck, CanadJ

3x 350 MW B&W Boilers

Sixlcen new low-NO" OlJlOrimulsion burners, eight reburn burners, nine SOFA ports. two eombmrtion air

boosler [un~, reburn and OFA wall penelralion opening,;, OFA windboxes, ductwork, dampers, "nd

accessories w~-re added!]).

-Anolhcr_lechnical.pJpeLshowclllbis reburn syslem !owcred.1,rax by 78%Jrom.J _0 lbfrrunBtll ba~elill.c ~.

0.22 lbJmmBtu.1 25 percenl rebum fuel inputl').

Source: 0) B&W 2004 Technical Pnper,IS) DOE-NFrL Scorecard On Reburning 6/112004 (from 2004

Rehurn Conferc"lIcc).

Gcorgia Power Pulverized Coal, TaogeolialJy-lircd

Scherer UniL 1 1982 vinlage

-887 MW CE boiler 2000 oil rebum starrup

GE-EER 011 Rebum syslem, claimed to 10werNOx from baseline of0.36 lb/mmBtu_

GE-EER 2004 Technicall'aper shows reduction up La 48% (10 0.19Ib/mmBtu) al800 MW load with oil

rebum operation. No cJaim~ ofperoent reburn fuel included!"').

Souroe: Sept. 2005 GE-EER experience li~t ~hows Ihis as a co~] robum project wilh eliSlem biluminous

coal, reducing NO" emissions 33% rrom 0.36 to 0.24 lblmmBtu;

(N) GE-EEIl2004 Teohnical paper. Not liSled in I') DOE-NETI. Scoreoard on Reburni~g 6/1/2004 (from

2004 RebuTTI Conference).

REBURN- COAL, M1CRONlZED, CONVENTIONAL

Pulve~jzetl eoal_li~ed bOilers

AES (formerly New Yark SI"le Eleelric and Gas Milliken Stalion Unil 1)

Cayuga langenLially-fired, pulverized cool, ] 956 vinlage

148 MWe, CE boiler eastern bjUlminous co.1

GE-EER mjcronired coal reburn syslem ]996 Slartup (still opcroling)

US DOE Clean Coal demonslrnlion project from March 1997-April 1999 lowered NOx with this rebum

system by 29% from 0.35 Ib/mmBtu baseline 10 0.25 IbfmmBtu at i4 percenl rebum fuel inpul!'). Nol

lislCd in GE-EER's expericnce lisl nor io their 2004 lechnical paper.

Source: (') DOE-NEfL 2004 Reburn Conference lechnicJI paper and DOE-NEIL Scorecard on

Rebuming 6/1/2004 (from 2004 Rebum Conference).

MinnkOl' power Cooperalive, lne. A2_17 Bnm' & McDonnell
NOx BACT Afialysis Study AJ'PENDLXA2

II.S. NOx Control Tlelror,t ProjtCIS

RE811RN . COAL, MICJWNIZED, CONVENTIONAL ("vllli-II"ed

Puh'crized coal_lired lJoil~n

E. ON US Holdings (formerly Louisv,lle Gas and Eleclric)

RD. (ireen Slation Unils ! & 2 (KY) wall_lired, rIlTv~'Tizc!l coal, vinlage unknown

293 MWc, 2 bOIler" easlern blluminous coul

GE·EER cuul rebum syslem Slarllip !lalcs: 200J & 2002, respeolivdy

Vendor daimcd LO lowcr NO" up 10 57% Irom hnseline of 0.45 IblmmBlu 10 0.20 Ib/mmDlu aI 1'ull]oad

wilb rebum opcTotion.

Rd,,'rn ~y'km lislcd on 101'A's "Scnrccllul un R"b"ming 61112004" "how$ NOx lowL.,-eu by 44% from

baseline of0.45 lh/m",Blu down lo 0.25 lMnmfilu (Wilh unknown rcbum fud input(>').

Another Icchnic.1 paper showed hn~elinc NOx wlth exisling 10w-NOx hurners Wa, OA51blmmBlu, and

reduced NOx emlssion 40% 10 0.27 Iblmmfilu Wilh OFA, alld lurther r"uuccd NOx emissions 22% down

10 0.21 IblmmBl" wilh lbe coal rehurn 'yslc"Tll in operation".

Sou, ce, (j) nOE.NETL Scorccurd on Rebul'Iling 6/112004 (from 20041tcbum Conference);

1"1 GE Encrgy 2Ull'! Technical pap'-"!", ,mu ",j Mareh 20U4 Modem Power Syslems i"ue.

Cheng Loong (nol in United Stale.,)

Unil #1, 250 MWe wall-fired, bilummous pulverJ7.ed coal, vml"gc & mfr uulOlown

GE-EER co,,] rcbum system 2000 Starillp (slill opcmling)

Source: GE-EER eXljerie"oc li81

Vendor chimed 10 lowcr NOx 44% from hasdine 0.451blmmBtu 10 0.25 Iblmmlltu) at rul! load w,'h

OFA nlone; f1ll1her reduccd NOx 28% 10 0.18 lb/mmllll1, lor 60% ovcrall rcuuclion. Recent (2004) dnla

shows NO~ duwn lu 0.14 lb/lllllllJtu (69% nvcmH) wilh up lu 30 pcrcenl rebum Jucjl-"I.

Source: I") G1'. Energy 2004 Teehlllcal pape,; GE-EER eXI,erie"oe li~l. Ll,I,·u m ('J DOE-NETL Sco,ccn"l

on Rebuming 611/2Ull'! (from 2004 Re1J1lm Confcr<-"T1c").

Rh~BURN-GAS, CONVENTIONAL wSNCR

l'ulveri'.ed conI_lire,! boil,'nl

l'.'RG SumlT,cl PUlwrizcd ("0;11. T,mgc"Iltiully-lired, vml"g~

lJmt (, Boiler l( (NY) GE-loER Conventional ('os Rehu( n,

120 MW CE boiler I'uel Tech SN("R, 2003 slm1up

Rcbum vendor claJmed ,olower NO" 55% ITom 0.45 Ibimmlliu ha,el;nc 10 0.20 lbimmlliu 01 fulllo.d

wllh rcbum operaliun bllmmg Venezuelan ~o"L The SNCR 'YSIClll furlher reduced NOx crnisoion' 45%

uown 10 0.11 Ib/mmfilll, for all ovcr;lll Tc<!ucl,on of 77%.l'O).

Sourcc; S~"pt. 2005 GE Energy experierwc h,'; ("I M'lTch 20ll'! Modem Power SysltmS ios"c.

/{£'lJURN - FUl:;L LEAN GAS REHURN (FLGR)

1'1Ilveri1.ed coal_lirerl hoil~,.,

Duke Power Company lallgenliully-fircd, pulverized coal

RiverheJld Unit 7 casIei'll billlmil\ous coal 1954 vinlagc

140 MWc, CE boiler 1998 FLGR "Iartllp,.gas reburn decommi"ionctl Smce Ihen

]'reviou"ly in'lalled ABBICE'~ Low NOx Concenlric Firing System (LNCFS-I) with C1ose-Couplcd

Overfirc Air (CCOFA); (pre-mod NOll + combu"'ion mod" dale not known).

Commcrc",1 FLGR installation claimed 34% NO" rcuuclion ITom full-load b"-'eline of OA2 lblnmlH(u

down 100.29 lblmmBru "II lhe combuslion modiiicalion" and FLGR g.o rcb"m fuel al 7% oriola! boiler

hoal inp"t. CO cmi",;ious werc above 1000 ppm correclcd 10 3% o,.IZI'

V<:ndor cl.imed 10 lower NOx 57% from 0.47 lb/mmBlu ba""line to 0.20 lblIUJIlHlu) al full load wilh

""pnnllc"<1 OFA alonc; further reduced NOx 45% 10 0.] 1 lblmmBlll wllh low-NO~ b"m~T', OtA, ga"

rehum, and SNCR, lor 77% o~cmll reduclion; no claim' ior amounl ofrcbum fuej!"'.

Bul'O" & McDonnell A2_1S MinnkoIO Power Cuupor.rlivc, Tile.
APPENDIX A2

U.S. NO>< Conlrol Retrofit Projects

NO>< BAef Analysi, Study

-."

-~_.

EPA's "Scorecard on Rebuming 6Ilno04" showed this rebum syslem lowered NOll by 25-30% wilh 5-

10 percent reburn fuel inpul('I.

Source: (21) ESA, GRI, NGB 1998 Technical paper;(2<) GE Energy 2004 Technical paper; <') DOE-NElL

ScorcCllrd on Rehorning 61112004 (from 2004 Reburn Conference).

REBURN _ FUEL LEAN GAS REBURN(FLGR) eonl;rlU<'d

Pulverized coal-fired boilers

Wisconsin Electric Power Company (WEPCO)

Pleasant Pi<lirie Unit 1 Oil Riley, lurbo-fired PC, Powder River Basin coal

620 MWg 1980 vinLage ,1999 startup

Fuel Tech lisled FLGR insLallaLion and claimed 20% NOx reduclion from ba.'<Cline of0.45lbfmmBlu (10

0.)61bfmmBtu). No claims ofpercent reborn fuel inpul included.

Source' Fuel Tech experience; listdaled 112812005. ('J OOE-NETL Scorecard on Rebuming 61112004

(from 2004 Rcbum Conference). (Also see FLGR + SNCR insLallalion summaries for pulverized COJI

boilers).

REnURN- FUEL LEAN GAS REBURNw/SNCR (Amine-Enhanced FLGR)

Pulverized coal-fired boilers

Carolina Power & Light (Progress Energy)

Asheville Unil I Pulveri7,.ed Coal, from wall fired

200 MWe DB Riley boiler 1964 vimage, eastern biluminous coal, June 2000 startup

Commercial urea-hased Fnel Tech SNCR +FLGR inslallation claimed 50% NOx reduction from baseline

·ofO:58-lliImmBru(426-pPnijuowrHo-02inbJ'mmBtu wI 51>pm arnrnonia·slip(l). -tow NOx·burners were

previously relrofiUed in 1997 witOOul ....l>'I[1lted overnre ai.-!"l. 111" is )] % lower lhan 0.44 lbfmmBtu

baseline for SNCR alone. (Also see SNCR inslolIalion summaries for pulverized coal boile"'). Ur...-loNOx NSR nol sLaled_ ,;

EPA's "Scorecard on Reburning 6/112004" showed this SNCR--enhaneeu reburn sy,lem lowered NOll by

25-30% with 5- JO percenl rebum fuel inpul in 2000, bul not eurrenLly operJtingl

').

Another leclmical paper showed 52% NOx reduction down 10 0.28lbfmmBlu at all loads, from 99 MWg

to 207 MWg (48% 10 100% MCR) with an average NH, slip of) ppm. FLGR alone achieved 2)% NOx

reduclion wilh 6% rcbum fuel and < 400 ppm CO at full load. (1')

Source: Fuel Tech experience lis!, (l)ICAC While Paper; (') DOE-NElL Scorecard on Rebuming 61112004

(Jrom 2004 Rebum Conference); ("l CP&L and Fuel Tech 2001 Technical paper.

(Also sec SNCR installalion summaries for pulverized coal bOIlers).

Public Service EnlCTJlrise Group (PSEG) Power LLC [formerly Public Service Elccuie & Gas ofNew

Jersey (PSE&G)]

Hudson Stalion, Unit 2 Pulverized Coal, opposed-wall-fired, 1965 vinlage

660 MWe Fosler Wheclerbollereastern biluminous coal March 1999 staJ1up

Commercial SNCR + FLGR urea-based Fuel Tech installalion c1Jimed 40% NOx reducllon from baseline

of0.65 IbtmmBlu (down 10 0.39 Ib/mmBlu) wI 10 ppm ammonia slipll). This is 20 % lower than 0.49

IbfmmBtu baseline for SNCR alonc. Urea-lo·NOx NSR nol stated.

EPA's "Scorecard on Rebuming 61112004" showed lhis SNCR--enhanccd reburn syslem lowered NOx by

25-~0% with 5-10 percemrebum fuel inpul in 2000, bul nol currently opernling('l.

Source: Fucl Tech experience list, (l)lCAC While Paper;t'l DOE-NETL Scorecard on Rebuming 61112004

(from 2004 Rebum Conference).

(Also see SNCR inslallmion summaries for pulverized coal boilers).

Minnkola Power Cooperative, lnc. 1\2-19 Bum. & McDmUl.U
RERURN- FUEL LEAN GAS RERURN ...I SNCR (AnrilJe_En1lallced FLGR) continaed

Pulverized coal_lired boilers

Pnblic Service JOnlerprise Group (PSEG) Power LLC [formerly Public Service Electric & G"S ofN~'W

Jersey (PSE&(;)1

Mercer Sl"lion (2) twin-furn""c boiler:;, 320 MWe each, OIl Riley lurho-fired

IJm! I and IJnit 2 Ironl wall PC, wet-holtom (slagging ash) easlern bituminous coal

Furn;,cc 1111 & 1112 19G0 vinlage M"y 1999 "Iarlup

Furnace #21 & 22 1961 vJn1.age May 1999 slartup

Commercial urea-ba.'ed Fuel Tech SNCR + FLGR inslal1a~on claimcd 60% NOx reduclion from b",;clinc

of 1.4 IhlmmBlu (down 10 0.56IblmmBtu) "II 5 ppm.ammonia slip m This i.' 72 % lower than 2.0

Ib/mmBtu baselme wiLhout conlroL Initial demonstralion of AEFLGR "oinjcclcd .minc-cnh;mccd natur"l

gas into Furn~ce 22 in 1998. Subscquently inst"lbl AEFLGR on holh unJL, 10 reduoe NOx staning in

May 1999 using (2) levels of AErLGR retraclable ga" injecLors and (2) levcls ofSNCR injeclor"I>9I_

Urea-lo"NOx NSR nol "["lcd, goal was NSR < 1.25.

[Nolc bolb unil_ have 'ince heen relrolltled with low--<lust lail-end SCrb in 2004; SNCR systcms UTe slill

capahle and uperaLcd as ncc-<led, moslly for ny"sh condiIioning 10 aid ESP perform.ncel

EPA's "Scorecard on Rehurning 611/2004" showed lhis SNCll-enhanccd n::burn sysLem luwenil NOx by

25-30% wilh 5-10 p~TCCnl rcb"m fuel inpul in 1999, hut nOl currently operating('J.

Source: Fuel Tecb experience lis~ ('JICAC Wb,le Paper; ('") I'SE&G, IT and ESA 2000 Technic"l

p3l'el';('1 DOE-NETL SCUTl"C"ul on Reburnin1l61112004 (from 2004 Rehnrn Conference).

NOx BACT Analysis Srudy APPENDIXA2

U.S. NOx Comrol Retrofil Projecls

,.

j

Cl d

,

,

,

-j

Wiseonsin Electrio Power Company (WEPCO)

Pleasant Prairie Unil I DB Riley, turbo-fired PC, Powder River Basin coal

620MWg 1980vinlage 1999storlup

Fuel Tech urea-h..,ed SNCR +1'l.GR demon<lralion inslallation claimed 56% NOx reduction from

bnsellllC 0[0.45 IblmmBlu Lo 0.20 lb!mmBlu "115 ppm .mmoni" slip(l). This is 44 % lower Ibnn 0.36

Ib/mmBlu haseline lor FLGR alnne.

EPA's "Soorce"r<l on Reburning 6/112004" "howed Lhis SNCR_enhanced reburn sy'lc"TTl]owered NOx by

25-]0% with 5-10 percenI rehurn fuel input in 2000, bul not cUiTenllyopern1ing(5J

_

Sour",,: Fuel Tech experience li,t, O)ICAC WhilC rupee und F.T. experience list 0207;

('J OOE-NETL Scorec.rd on Reburning 61112004 (from 2004 Reburn Conference).

LOWNO. BURNERS (Repincemem or modijicmioJLS) wiaJJdw/o OVERFJRE AIR

Pul"erizetl coal-Iired boilers

AEP Cardinal Unil I Pulverized Coal cell-burner, oppo,od "lull-fired B&W boiler

600 MW (nominal) 1967 vinlage; Low NO, burners insmlled in October 1998

Producc<:l 0.75 lbfmmBlu NOx pust-LNB iru;"'11 b.oclinc aL [ull load_

LNBs reduced NOx 57% from 1.20 down to 0.52", produce NOx at "pprox_ 0.57lh/mmnlu at min. load

wlo SNCR (range 0_51 100.65) and produce 0.751b/rnmBLll NO" al approx. 585 MW (top of load r"nge

tested, NOx range 0.73 to 0.861b!mmBlu)(l1).

(50) original B&W circular burner" were recenllyrcpl""cd on Cardi""l Units 2 & 3 by Buckeye Powe,

with OIl Riley (now Ftabcock Power) CCV type low NOx bumers.

Source: ~Riley Power (Babcock Power Inc_) RlI (,/04 exrerience lisl; (7) 2000 Fnel Tech technical paper.

(A1:;0 """C SNCR irl.';tallation sunu""ries for pnlveri""d coal boiler").

C"rolina Power & Light (Progress Energy)

A,heville Unil j PulveTIzclJ Cu"l, [ronL "lull fired

200 MWe on Riley boiler 1964 viLltage, ea.,lern hilumiLlou._ coal, June 2000 'l.rtup

Low NOx burners were previously retrofitted in 1997 without separated overfire ai~"I. NOx reduction

was 46% [rom pre-LNB inst.ll,,'ion b"sclinc of 1.081blmmBIu (121 down 10 O.58lb.lmmBtu (00)_

"·l

, j

,

J

J

Dums & McDonnell Al-20 Minnkota Power Coopcralive, lno.
APPENDlXA2

U_S. NOx ConlIol Retrofi( Projec1S

NO" BACf Analysis Study

(Also see SNCR, and FLGR with SNCR installation summaries for pulverized coal hoilers).

Souree: 112)2005 US EPA Docket OAR-2002-0076-0446 Technical Support Documenlspread.,heel; I")

CP&L and Fuel Tech 2001 Technical paper.

LOWNO., BURNERS (Repluc£nteJll or modifica/ion.<) wIaud w/o OJ/ERFJRE AIR COlllin"ed

Pulverized coal-fired boilers

Carolina Power & Light (Progress Energy) Pulverized Coal, Tangentiully-fired

Cape Fear Unit 5 1956 vinlage; eastern bituminous coal

154 MW CE boiler ROFA startup in 2000

Mobo,e. USA's Rotating Opposed Fire Air (ROT-A),is a high velOCity boosted separated ovcrIire air

system claimed to lower NOx wilhout retrofitting 10w-NOx burners. This was the firsl U.S. inslallation of

Mobote. USA's "Rotating Opposed F,," Air" (ROFA) On a ulility boiler, which ulllizes a booskr fau.

CP&L technical paper claimed to lower NOx 53% ITom full-lo"d pre_ROFA baseline 0_60 Ih/mmBlu 10

0.28 lbfmmlllu wilh ROFA alone following lhe install"tion ofROI'A in 2000(").

Source: {HI) CP&L 2002 Technical paper. (Also see SNCR installution summaries for pulverized coal

hoilers).

Camlina Power & Light (Progress Energy) Pulverized Coul, Tungentially-fired

Cape .Fear Unit 6 lwin-lilrnac-e (eight comer), ]95B vinLage; eastern bituminous coal

175 MW CE boiler ROFA staTiup in 200]

This unil's "ROFA" system was installed as part ofa "Rotamill" SNCR + ROJo'A system.

CP&L technical paper 'hows ROFA alonereduced NOx 57% from fuJi-loud prc-ROFA haselinc 0.54

lb/ri1mEiilil(la-NOx emiS:,ionniie oHJ:2J·llifmrnHtil---:- I")·- _..----

Source: I")CP&L 2002 T~..,hnical paper. (Also see ~"'NCll installation summaries fur pulverized coal

boilers).

Coneeliv (formerly Delmarva Puwer & Light)

Indian River Units 3 &4 (Minsboro, DE) Unit 3 is [mnt wall-fired, 1974 vintage

17HIylW and 440 MW Unit 4 is turbo-fired opposed-waH, 1980 vintage

B&W, DB Riley boilers euslem bituminous coal

RElperronned CFD modeling OLl hoth units for potential SNCR upplicatlOn.

Unit J has Riley Low NOx burncr>; (16), (R) front wull and (R) rear wall OFA pons, (8) wall boundary air

ports, (66) side wall OJoA SIOIS, clallned baseline NOx around 0.37 lb/mmHtu w/o SNCR 1101_

Unit 4 has (24) front and rear wall down"nred burners, (28) front and relIT wall SOFA paris, clulmed NOx

uround 0.44 lbfmmBtu w/o SNCR (W) (furnace has "Mac West" belt}.

Riley provided 16 CCV low-NO.~ humers for Unit 3 in 1994, und cl"imed to "educe NOx emissions by

67% from pre-LNB baseline of 1.051b/mrnBlu down to 0.341b/mmlltu.

Source: 1'°1uoI J999 Technical Paper; Ril,"Y Power (Babcock Power Inc.) 8/16104 experience list. (Aloo

see SNCR inslallation summaries for pulverized coal boilers).

Dayton Power & Light Pulverized Coal, Tangentially-fin-d

Killen St:ation, Unit 2 1955 vintage

632 MW CE boiler, bituminous Illinois coal

GE-EER provided low-NOx burners in 1999. Vendor claimed full load NOx was reduced by 23% from a

0.57 Ih/mmBtu ba,eline down to O.44lbfmmRtu_

Source: GE-EER Experience 1;sl2/1/02_ (Also see low-dust Sell installatiun list for pulverized coal

boilers)

Minnknla Pow~r Coop."'tiv€,Inc. A2-2J Dums & McDo"ncil
NOK BACT Analy:;i, Study APPENDIX 112

U.S. NOK en"I'O] ll.elrufil Projects

LOWNUx BURNRRS (R"pl""nm",t or nrodijicatiOllSj """lid "'/0 OVERFIlll':AIR COmilllll!U

Puh'erizetl cll1tl-fired boiler.'

Dynegy M,clwesl Generation (formerly Illinois Power) ]'u]yen7.ed Coal, wall-fired

lIavana Slnl,on, Unil6 1~78 vint;,~c

460 MW B&W boiler, bil"m;nou, lIIinoi.' coal

C,E-EER provided modi Iications 10 lhe original il&W dual·r~glS\cT burners, and a" OFA 3yslem in 1000.

Vendor claJJned [uliload NOx was uncbanged [wm 0.38 lb/mmFllu baselinc.

Souroc; GE-EER Expe, iencc lis12/1/02. (AI,o see low-du:>l SClt ;nstallaIlOLlliSI [or pulvem.ed coal

boilers)

Dynegy Mi<1w~sl GeneratJOn (limnedy JIlinul' l'owe,) Pulvcrizcxl Coal, Taugenlially-i1red

V~nnjl1ion Slalion, Uml I 1955 vinlage

81 MW CE bolier, h,luminolls Illinois co,,1

'I'his rowling oppose<l fir~ uir (Mobolcc USA ROFA) syslem wa, imlallcrl in July 1001, ns pari ora

"Rowlni," SNC"R + ItOI'A sy'le"" wilhoul low-N(lx bu",e,s.

Mubulcc 2004 tecnnical paper ~bimed 10 lower full h'd NO" by 62% from 0.58 Ib/mmBlu hu,dine lu

O.l1lh/mmBllI lU July 1001 (w,lhoul r.NB Or SNCR). (")

Suure~: en) Moborec 2004 !Cehmc,,1 p;lp<.T. (Abo .".., SNel\. installalion SUrrlrm'nes [or pu]veri""d ,,,~,I

hoilers).

Georgia POW'-T Pulvem.ed tu"l, opposed wall-firecl,

Harke Branch Unil 1 250 MW B&W buib, 1965 vinlage 2003 "lm1up

"arlee B,--unch Unill J59 MW Rlley boiler, 1%7 vinl"ge 1998 ,Iartur'

B&W provided 24 DRB-4Z low NO" burners [or Unit I B&W bOiler, 2~ DllB-XCI. luw NOx bumers

for 1111il 2 Riley bOll" (bel,eve ,ulJlk~,,1 "oasl ligoil~ is primary [lIel)_

Som~e; B&W's e~pcTicu"eI;s!. No NO" reduolion claims.

Kam;a" Clty Power & Lighl Pulverized eoul, opposed wall-tire,], 600 MW B&W i1uilor

fhWlhom Unit 5 30 !lUmers, 200 I v,ntag~, (powder It,vel' na'in "ual)

B&W provided JO DRB--'1Z low NO" burn~rs mulll OFA ports wilh lh~ new bOller.

$Olll'CC; B&W's e"perleoce IJSL No NO, reduclion c1oims.

New England Power Company(NEPCO)

Snlcm Harbor Sialion Pulverized Coal, Iron I wall-fired,

Unils 1,2 & 3 1952, 1952,1958 vinlage (eo.\lcTIl bit. coal)

84 1\1\"'0" 2, & 156 MWe B&W boiler> tNt!> slartup In 1995, 1995, "nd 1993

Kiley claimed Unit 1LNB, reduced NOx em;,,;olls by 57% from busc!ine o[ L10 IhlmmBlu dmvn co

0.42 IhlmrnBlu; Unill'3 I.Nlh .chicvcd 42% NO" 'educli"n from a ha.,eliTle "r·O,95 Ih/mmBlu <luwn 10

0.55 IbJrnmR\IJ; UniI3'., LNlls Jchiev",1 60% NO" reduclion [rom a baselJlle or ].05 IblmmBtLl ,Iown 10

0.42Ib/mmBlu.

Source: Riley Power (Babcock Power Inc.) 8116104 experiencc Ii,!.

(Alsu ,cc SNCIl ;tl31.1I'lion ,"mmarics [or pulvcrizeu eoal boiler,).

Northeml UlilillC' ([orme,ly Poblic Scrv;"c of New Ilnmpsl,irc)

Sh,lkr Slal,on Pulverized CooIJI16 Fuel oil, fronl_wall_fired

lJnit.'~, 5, &6 1952, 1955, 1957 v;olage

50 MWe x 3 Fosler Wheelcr hoilers

RJlVl provided (6) l."w NO, bunK, modiJlcaliuns pCT boller in 1994, ]992, & 199~ 10,p"cl;vcly;

LNIls rcdll~cxl NO" ~3% Jrom 0.85 10 0.48, 50% lrom 1.0 10 0.50, Jnd 51% [rom 0.82 10 O,~O Ib/mm[J(u.

Souree: RJM expcrien~c lisl

·,il

llum' & McJJolloell 112_22
APPENDIXA2

u.s. NOx Comrol Retrofit T'rojocts

NO"BACT Aoaly,i, Study

LOWNO, BURNERS (Replacement ar maJijicaritJI1.') wialld wI" OVERFIREAIR Ctlntinued

Pulverizod ooal-fired boilers

Potomac Electric Power (formerly Wesl Pennsylvania Power)

Chalk Poinl Station Pulverized Coal opposed wall_fired

Units I & 2 1964, 1965 vintage cnslern biluminous eoa]

360 MW (nomin"l) B&W boilers

DB Riley (now Babcook Power) CCV lype low NO" burners relrofilted in ]993 and 1994, respectively.

Vendor claimed to 10WlT NO" up 10 52% and 50% from 1.35 and 1.40 lh/mmBtll b"sdin", (10 0.65 and

0_70 IblmrnBlu, assumed al full load).

Source: Riley Power (Babcock Power Inc_) 8/16104 experience Iisl. (Also see Convenlional Gas Rcburn

installation summaries for rulverized coal boilers).

Xeel En"rgy (formerly Puhlic Service CompJny ofColorado)

Cherokee Unit 3 Pulverized coal, wall_fired, B&W boiler, 16 hurners, 1962 vint"g"

175 MW October 1992 ba,din" testing sta,1ed (weslem bituminous coal)

Installed (16) Fosler Whccl"r Conlrolled Flow/Split Flame lo'v NO, replacemenl burners "s part of a

DOE Ckun C.oal Technology gas reburn dC"TIlOnslraliilll perrormed with Gas Rcsearch Inslitute 1992-

1995_

Unconlrolled NO" wi original B&W flare-type burners w"s 0.73 lh/mm81u. RJ.:plueemcm J.NBs

(as.-,uming OFA included) reduccu NOx 37% 10 O_461hlmmBlu125J•

Source: (lj) DOE NETL 200 I Technical paper.

-0;

----,----

A.2,2 -------;ycchiiic;,:-i{ileraillre References for U,S. NOx Con-lroi"Rctrofil Projecls:-

II) SNCR While Puper, lnSlilutc of Clean Air Companies,lnc. (ICAC), SNCR Committee, May 2000,

Fuel Tech wellSlle ttilI);llwww.fucltcehnv_eomfpdrffPP,534,R<;If

i»RE12001 Technical Parer "Design anu Demonstration ofRich Reagent Injections (RRI) Performance

For-NO" Redu"lion at Connectiv's BoL. England Slation'· by Murc A_ Cremer und Bradley R_ Adams,

Reaclion Engineering Inlernalional, David C- O'Connor, E1eclric Power Research Inslltule, Venkalu

Bhamiuiputi, Conectiv R.I._ England St"l;on, onu R. Gifford Broderick.IUM Corporalion, presenled al

lhe 2001 US EI'NDOEJEPRI MEGA Symposium on SCR and SNCRs, Chicago,ll., Augusl 20-2), 2001_

(REI wcb,ile hllp:f/www_reaclion--eng.comidonwloJu,./rri mega_pdQ

I') REl2002 Technical Paper"Demonslralion ofRi"h Rcugentlnjection for NOll Control in AmerenUE's

Sioux Unit]" by Marc A. Cremer and Bradley R. Adams, Reuctiilll Engineering lmemaliilllal, Duvid E_

Boll, AmcrcnUE, and David C. O'Connor, Eleclrie Power Research Instilulc, presenled at lhe US DOE

Conference on SCRlSNCR for NOll Conlro~ Pitlshurgh, PA. May 15-16, 2002; and

REI 2003 Technical Paper "Improved Rich Reagent Injl:Clion (RRl) Performance For NO" Conlrolln

Coal fired Utllily Boilers" by Marc A_ Cremer aTId Huafeng D_ Wang, Reaction Engineering

IntemationJI, David E. Boll, AmerenUE, Edmund Schindler, RJM Corporalion. anu Edmundo V~sque7~

RMT, Inc., Alliunl Energy C0f]l_, prcscntc<l al2003 U.S. DOE Conference on SCR ami SNCR for NO"

Control, Pi~sburgh, PA, Oclober 29-30, 2003.

(1) REI 2004 Techni,",l psper, "Eva!uJlion ofCost Effeclive Non-SCR Oplions for NO" Conlrol in PRIl

Fircd Cyclone Roilers" hy Marc A. Cremcr und David H. Wang, and Bmdky R. Adams, Reaction

Engineering Inlemalio""l. David E- Boll and KeoneLh B. Stuckmeyer, AmercnUE, pre.,enloo allhc

Western Fuel" Sympo,ium, 19'1> Jnlemalional Conference on Lignile, Brown, and Subbiluminou:; Coals

(formerly Low_Rank fuel<), Oclober 12-14, 2004, Billings, MY.

MlIlnkOLa Power COOI,crdlivc, Inc. A2-V [Iums It McDonnell
i'lOx BACT Analysis SI"dy

-----

APPENDlXA2

U.S. NOx Control Retrofil ProjeolS

: REI 2005 Tcchnical P"P<-T "NOx /:;missiom Below 0.15 IblMhtu Aehic~cd ill a Cyc1one""irerl BoikT

U,ing: In-Furnace Conlrol" by M. Cremer, B. Adnms, nnd A Chiodo, Reaolion /:;ngineering Inlernational;

C. Gie,maon, K. Stuckmoyer, and J. Boyle, AmercnU/:;, presenled at Ihe Po",erGen Internalionnl 2005

conferenee, December 6-8, 2005, Las VCl}lS, Ncvada.

(5) DOE-NETL 2004Tcchnicall'aper "Rcbummg Projects in the Deparlment of Energy's Clenn Co"l

Technology Demon.'lr"lion Program", by Al Mann nnd Tom Ruppel, Parsons Corporation, and Tom

Smkus, National Encrgy Techmcal Laboratory, presenled al the 2004 DOE-NET!. Cnn t"renee on

Rebllrning lor NOx Conlrol, Morg,m lown, "WV, M"y 18, 2004. A reburn-related doculllenl (an "l'daleu

vcr"ion ofu posler ffOmlhe May 18 Conferenoe) i.' Iitled "Sco,-~ennJ On Reburning 6/1/200-4" by Al

Mann and Tom Ruppel, P"Thons Cmpomlion, "vailubk on-line ai,

hllp:!lwww.ncll.doe.go-".!QllbIJcaIione!m:q{<;.e_d.i.ngs/041NOx/posLe~lRcb"rnlng%20Scon:omd.pdf

(.j GE bJergy 200~ Technical paper "Reburn Technology Apl'lie~ljonGui,ldincs", by David Moyeda,

GE Energy, I'reoenleJ "Ilhe 2004 DOE-NETL Conference on lleburning tor NOx Control", Morgantown,

WV, May 18, 200-4.

1'1 B&W 2004 Technical Paper '-Il&W's RebUlning Experie"ee", hy H. F~Uflll, G. Maringo, A. Yagiela,

A_ Kokkino" Babcock & Wilcox, ("0., prc,enlcu allhe 200-4 DOE-NETL Confel'ence OLl Reburning [or

NOx Control, Morgantown, WV, May IH, 2004. (TIlis dal' is;l duplic"lc of;, more uet"iled technical

paper publi,hed enrlicr, "B&W's A,h-"noe On Cyclone NOx Control Via Fuel and Air Siaging

Tcchnologies", by II. ",,,zan, G. Mnringo, D.W. Johnson, and D.W. Won!" B"beock & WIlcox, Coo, c.T.

Beard, r""-\Iman Ko<l"k Company, and S.E. Brcwsler, Tennessee Valley AUlhOl'ity, presenled at Ih,' El'IUDOE-.El'A Comhincd Ulilily Air PolhJlanl Conlrol Symposium, Allanla, GA, Augusr 16-20, 1999)_

CO) H&W case hislory "B&W Cyclone Reborn Le",ls 10 NOx RcdllCliol1, Wiseonsin Power & Lighl Co.

Neboll Dcwey Unit No. T' (from website hllp:l/www.bahcock_com/pggip.•le".\ehislorie•.hlml••laled

1997).

r') DO/:; Topical RerorI Numl:>er 14 "Rebunling Technologlcs for Ihe Control Of Nilrogen OxiJe,

Emi.'sions from Coal-Fired Hoilers", conducled under ""ramIe cool'eml' ve agreemonts l:>el",een Ihe U.S.

Dep'lftmcnt ofEnergy, lhe Bahcock & Wilcox Compnny, lin""l:}' .ml EnvlTonnlC"Ill"1 Rcsearch

CorpOfalJon, and New York Sial,· Elcelrie & Gas Corpomllon, May 1999_

{LOJTechLlical Pap"" "PreJi"llUns ofFLGR al Commonweallh EdIson's JolieI Unil6" by NGB

Tcdnologics, posted on lhell' ",ehsile: hltp:!lwww."{(blech wm/subp"l!cs/proj/joliot ccsul1'!.hlllll

(111 REI 200 I Technical paper ··CFD Eval"alion ofFnel Lean Co" Rcbunl (F1.GR"') ,md Seleclive NonCalalytic Rcdu"tion in Owensboro MlInic,pal UlillI;es' Elmer .sm,lh StaI10n", hy David H. Wong, Marc

A. Cr"mcr, and Dradley R_ Adom" Reaclion Engineering Inlcrnation"l, K.D. Frizzell, Owen,bol'O

Municlpallllihlies, "nJ G.c. Dlisalko, S"rg"nl & Lundy, 2001 US EPAIDOE MEGA Symposium on

SCR "nJ SNClls, Chicago, II., Augu.<l 20-n, 200 1_

I"IUS EPA Dockcl OAR-2002-0076-0446 1l"Chnical .support DoclimeLll lor nART NO~ Limits for

Electric Genemtmg Units Execl Srread.,heel 61 1512005, postcu on Iheir web,ile:

hit1,:1/<Io"kcl.,=va, gov/c.dJellU hI~!>I EI)KS l~ fIl1ffi1De I~ iI\~~w" obi ecIId' 090007d4 8084562b

(IJ)Burns & McDonnell inlen"l dniahase.

Bum, "'- MeDonuell A2_24 Millnk"lli l'"weT ('oope,a!,ve, Ille
APPENDlXA2

u.s. NOx Co~trol Retrofil Project>

NOxDACf Analysis Study

(1') Technical paper ''Operaling Experience and Future Challenges With SCR Applicalions", by Gerd

Beckrnan~ and ClaylonA. Erickson, Babooek Borsig Power, Inc., presentcd at Power-Gen Inlernalional

2000, November 14, 2000, Orlando, FL

IJ<) DOE NEIL Technical P"P~T "Control ofNilmgen Oxide Emi",ions: SelcCllve Calalytio Reduction

(SCRl", Clean Coal TeehnologyTopical Rcpon Number 9, July 1997, posled on lhcir websile:

hl:ip:IIWl'(W.ne~.doe,gov/Dublicalions/OlhersilopicalsilopicaJ9.pdfs.

(") SCR White Paper, lu.titute of Cleau Air Comp~nies, Inc. (ICAC), SCR Corruniuee, November 1997,

http://www.m~moni"DrocomiAmmonia%20LibraryINOx%20Redl.clionfInslilmeo/020ol../o20

CJcan%20Air"/o20Co SCE Pllf, linkcuto R-M. Technologies web,ile http://www.rrmeoh.nellartieals.hLm

117) Technical paper ·'C'-lI.rdi~al Unil I L"rge Scale Seleclive Non-Calalytic Reduclion DemonSlrulion

Projecl", by l'alrick M. Malone, American Electric Power Service Corp, "ml Dr. William IL Sun, Fuel

T~"Ch, pre:;cnLed at !he ICAC Forum 2000, M"rch 23-24, 2000, Ros,yln, VA.

118ICP&I, 2001 Technical Paper ··Rolaliug Opposcd fire Air (ROfA) and SNCR·', by Mark Shilling and

Gary Tonamakcr, C"rolinn Pow~r & ljght Co.. presented allhe 2002 DOE-NETL Co~ference on Uabwned

C"rbon On U,ility I'ly,,-,h, May 14, 2002" Piltsburgh, PA.

('''Mobotec 2003 Technical Paper '·lnjc<:lion ofUr"" through the Rolamix System to ObLain Improvcd NOli:

Reduc~ou·., by John Ral'lou ;Illd Edwin lladdad. Mobotec USA. Inc., pres~"TIlcd at lhe 2003 U.S. DOE

'Conf.:rence' on SCRand SNCRTofNO;;: Conlrol~PiUsbiirgli, PA, OcLoher 29-30.-2003;-

(2O)RE11999 Technical Paper "CI'D Modeling ofSNCR Pcrformance in Conec~v's Indian Rivcr Unils 3

and 4", by M. Creme, "nd M. Heap, Reaction Engineering Inlernalion"l, M. Zoccola, Conecliv. and V.

Ci"rl~nl~, Hamon-Research C'-OltrelJ, pre""ntcd nl DOE Conference 0" SCR and SNCR for NO", Conlrol,

May i0:-21, 1999, Pillsburgh, PA.

(llJMobotec 2004 T~"Chnical Puper "SCR Levels ofNOx Reduction wilh ROFA and Rolamix (SNCR) at

Dynegy's Vermillion Power Slalion··, by KriSlopber A. Coombs, Sr., Dynegy Midwest Gencmlion, and Jay

S. Crilley, M"rk Shilling, and Edwin Haddad. Mobolec USA, Inc., presClllCd alLhe 2004 Slack Emi..,ions

Sympo.,ium, Clearwaler Beach, FL, July 18-30, 2004.

Ill) MiLsui Babcock2003 Technical pnpcr, "NOxSlar"" Plant Demonstration, Oclober 2003", by K-W.

Moms and G. Hesselman, Milsni Babcock (US). presentcd nllhc 2003 U.S. DOE Conference on SCR

and SNCR for NOx Conlrol,l>iltsburgh, PA, October 29-30, 1003.

(2]) MilSul Babcock 2004 Technical paper, "InslalJ'lliOll ofNO"S"'r"" SysLem at TVA Colbert", by Keilh

W. Morris, Milsui B"bcock (US), presenled althe Coal-Gen 2004 Confercnce, July 28_30, 2004,

Ovcrlrmd Pnrk, KS.

(2') GE Energy (formerly GE-EER) 1004 Technical paper ··Experience wilh Rebwn forN01< Emis.,ions

Control", by Don Engelhardl, Roy Payne, David Moycua, Blair Folsom, GE Energy, presenled at the

1004 DOE-NETL Conference on Rcbuming [orNOx Control, Morgantown, WV, May 18, 1004.

(5) DOE NElL Tecbnic~l pnpcr "Evalualion ofG<!, Rcburning and Low-NOx Bu",er. on a Wall-Fired

BOller A DOE ARSe.<smenl", dated February 100 I. oor,JNETL-2001/114J, posled on thcir websilc:

hLtr:llwww.neLI.doe..£!lv/cctclresouree&'pdf.<!eercolGRLNBPPADdr.

Min~kola Power Coopcrdliv~,lnc. /\2·25 Barns & McDonnell
NOx BACT Analysis Snody APPENDlXA2

U.S. NO, Conrral Rolrn~ll'cojecl'

I") GE En~r&y (formerly GE-EER) 2004 TeclmieaJ paper ·'Powerpl~nl mosaics: paving the way 10 0.11

IbfMMBlu without .sCR", by HI.iT Folsom, GE Energy, published in lhe March 2004 issue ol"Modom

Power Systems.

(17) NGB Technical ral,er '"["'uel L~an Gao Reburn (l'l.GR'''') Technology [or Achieving NOx Emis.,ion,

Complianc~: Application 10 a Tangentially-Fired Boiler", hy RlChanJ D. Frederiksen, WlTIln J.A. Dahm,

and Grelar Tryggvason, NGB Te~hnQIQgics,Inc., Bernard 1'. Dreen, Roge, GJickerl, and Jo.,eph A. Urich,

Eneqw Systcm> Asso<oiates, Jnd Jolm M. Pralapns and Robe'l V. Semuskas, Gas J{eseacch Instilule

(GIU), presented al Ihc 1998 Joinl Arncrie,nlhpanose Flame Rcse.,-ch Commiltce InlemutioTJ~J

Sympo,ulm J;;!1yLronmemal Conlrol ofC-OmhuSlioil Processe" I.nnovative TechnologyThwards ,he 21 <,

C,,-nl.ury, Maui, Hawuii, OOlobl, II 15, 1998.

"')2001 Tcc1mical PUp'T "Applie,li,," ofFueJ Lean (jas RehurTl Wilh SNC"R On i\ 198 MW Coal-Fired

UIlIily Boiler" by David Kille", Carol ina Pnwer & Llghl Co., Jobn M_ lJoyle and John JL 0 'l.eJry, Fuel

Tech Inc., pr~s~nlcd al thc 20UI US EI'NDOEfEI'Rt MEC,A .syrnposium on SCR ami SNC"R" ChIcago,

II.., August 20-23, 200 I.

t"ITcchnieal paper ·'Fir" Commercialln.,tallation of Amine Enhanced Fuel Lean Gas Rehum On Uml>; I

and 2 at Puhlic Service Electric & Gas Mercer Slalion", by A",lrew F_ Gomez, Publie Servic,- I:;leclric &

Ga, Company (I'SE&G) Mercer GeLleralirlll Sliltion, Akxunrler S. Damon· and John IL O'l.eary, Fuel

Tech, Inc., and Robcrl Seh,eec<lgosl, Enl,gy Systems AssociaLes, presenled at Ihe 2000 DOE-NIoTL

Conference on SCR and SNCR ror NO~ Conlrol, Pillsburgh, PA, May 17-18,2000.

...

Ilurn> & McTJunnell A2-26 M mnk"l.., Power Coop0,"IIV<, 111c.
APPENDlXB

EERCREPORT

Ash Impacts on SCR Catalyst Performance

ASH IMPACTS ON SCRCATALYST

PERFORMANCE

PrOf'll""" by:

Sleven A- Ben,on, PhD.

Enor~y & Environmenlal Reseat~h Center

Univor:sily ofNorth Dakota

PO Do~ 9018

Gnmd Forks, ND 58202-90 Ig

OClober 2005

,
,

:-;
TABLE OF CONTENTS

LIST OF FIGURES 11

LIST OF TABl,ES , 111

EXECUTIVE SUl\1MARY ES-J

INTRODUCTION 3

INORGANIC COMI'OSITION OF LOW-RANK COALS ..4

INORGANIC TRANSFORMATIONS AND ASH FORMATION 5

ASH DEPOSITION ON HEAT-TRANSFER AND OTHER SURFACES EXPOSED TO

ASH AND FLUE GAS 6

ASH-RELATED EXPERIENCES AT MRY 1,'AClLlTy 7

Ilislory 0 r Fu cn~ce SI oggingiFuullng _••,.,.,.,•.•.•.•.•..•.•.•...•.•.•.•.•.•.•.•.•__•.•.•.•.•.••.••••••• ,~., ._.•.•..•.•..•._.•....•.•.__ 9

Advanced Boiler Pec(onnance J"dices •._.•.•_ _._ ,••_,••••,.,.,.,.._.•.•..•.•..•.•.._.•_.•.•. ., 9

ASH-RELATED IMPACTS ON SCR CATALYST_PERFORMANCL 16

Full-Scalc Slipstream Testing __ ._ _ _ _. .. .. 16

SCR Ash Dep<Jsil Characlcrizalion............. .. .. 19

SCR Dern'il Fommlion Mcchilnisms _ _ " 20

Low-Tempcrnturc pyru,~lr"",s _ _. 31

Conclusion: SCR Is Not feasible FOR NOx MDUCTION at M. .-. young 34

REFERENCES 36
I.lST OF FIGURES

Figu,e L Variohili'y orseleoled oonSlimen\s in core anolysi' dOloba,e providc<! hy

FIN! Coal, L1u_ "nd Minnkola cool dOlo!>a,e _.. .. .. .. J

Figure 2_ Overall processes of a,h deposilion Iypical of a lignile- or

.,ubbiluminolls-lired hoiitr .._ . ...__ .. 0

Figure J. T"o frequency dislribution for all Coal Qualily Management System

(CQMS) dala, of -. .. 12

Figure ~. cI '" lilslIlbnlion lor Hi\ ,cam co"I ....

Figure 5. T", dislliblllioJJ for HB 'cam c(]ol " ..

Flgurc 6_ T"o dislrib"uol1 for KC ,cum coal ..

. 13

'" 13

. .... 11

Figure 7. Varimions in the delivered coal qualily during a lesl bUlll period ... _14

Figure 8. Weight ehm,ges ror PRB-blelld co~1 ash exposed lo flue gases and

ammOllia at Ihree lempemluIe' _ 21

Figure 9. Weight change' for PRE-blend conI ash exposed 10 fllie gases and

ammonia wilh and without SCR CJtAlysl present .. _ 22

Figllr<' 10_ CmalJ!" pLessurc dmp"1 B"ldwin ~IJljon JI 0 10 2 months of0l'eratlOn -. 22

::~

Figll,e 11_ Caluly,t pre"uTo rlmp at Coycle S"t[OI1 a\ 0 I" 2 monlh, of ~per,,';on ... n

fig,,,e I L C",uly_'l p",_""re drop "I C~JuJjlloio S,"IHlIl a\ 0 10 2 monLhs ~fopcr"li",, __

Fignre 13_ Piclures of cal~lysl inlet nlier about 2 months o[lesling at eacb planl

figun:; 14_ Piclure, ofcalalyst inlet aller aboul 4 monl118 of exposure 10 flue gas

JIld parlicu]ale __ ... _ _ .

......"...... 2.1

......24

.. 25

-- ."

Figure 15. ScM ;rrulgC' (][ ash collecLeo on ca'"l)"1 surf"cc al Ihc Boldwin Sialion

allor (, mOJllhs ~[exposuro ......... ". . ..'''''' ... 26

Foenre 16. SLM imigcs "I',,-,h colkolod on eolillyS! 'ur["cc allho COYOle S,,'I;ul1

anor 4 mOlllhs of ~xp""lLrc .........

Figure 17_ Compari'oll of cl1lr.il1cu a,h ano deposlied "sh OIl Gllalysl for Columbia Slal;on __

'"

Figuro 13. Mec],Jni,m u[SCR eololysr blindillg "i. Ih~ [mIl1ali"n "r "MOles ""u

coroo"ales (mudllicd alkT Pritchard alld oLhers (30)) -' _ ] 1

"
L1STQFTABU:S

Table 1_ Characteristics and Indices Calculated for Selected Center Lignite Samples

Table L Advanced Index Values for Other Coals (12)

'"

13

IJ

j;.",.

'C'_

ASH IMPACTS ON SCR CATALYST l'ERFORMANCF.

EXECUTIVE SUMMARY

The ~sh deposition behavior of the ligniles from North Dakota is the most complex ano

severe ofany coals in the world, and insl<lllation ofcatalysts for NO, reduction is going to be

plagued with problems. The Center lignite fired at the Milton R. Young (MRY) Power Station is

highly variable in abundance of various types of ash/slag-fonning components. Ash-foming

componenL. consist ofinorganic elements (sodium, magnesium, calcium, and potassium)

associated with oxygeo functional in the organic 'matrix and mineral grains (quartz, clays,

carbonates, sulfates, and sulfides). Upon combustion, the inorganic components undergo

chemical and physical transformations thal produce inteJlllediate inorganic species in the form of

,'norganic gases, liquids, and solids. The alkali and alkaline-earth elements combine with

minerals during combustion, resulting in low-melling-point phases that cause a wide range of

fireside deposition problems. In addition, the alkali and albline-earth elements also fonn very

small particles that are camed into the backpasses 0 f thc combustion system amI react with flue

gas to form sulfates that can cause deposition, blinding, and plugging problems in selectivc

catalytic reduction (SCR) sySlems. This report analyzes these problems, aod concludes that SCR

is not a feasihle option to control NOx emissions at MRY Power Station because ofthe high

sodium levels present in the coal.

Following is a list of the key problems that arc associated with Cenler lignite which have

not been overcome amI, in our opinion, make the installation of SCR at the MRY plant

technically infeasible for NO, controL

}> Blinding ofCat~lyst Por~s by High Sodium Compounds

X High levels of alkali and alkaline-earth elements present in lhe coal fired althe MRY

plant prodl1ce small particles that react to form sulfates that blind the calalyst pores. The

high levels ofsodium in the coals combined with calcium will produce lowme!ling"point eutectic sulfate compounds that will form and mell inside the pores ofthe

catalyst.

• Alkali and alkaline earth sulfates are enhanced by cyclone fired system. The cyclone

firing resulls in partitioning ofthe ash between botlam slag and the body ofthe boiler.

The sulfate fonning materials are more concentrated in the ash as a a resuH ofcyclone

firing.

• Sulfate fOJlllalion is enhanced by lhe presence ofan SCR catalyst; this accelerates the

sulfation reactions, causing blinding ofthe catalyst

The sulfate reactions nrc more severe at MRY because oflhe high temperature where

an SCR would be installed. The higher temperalurc increases the ratc offonnation of

sulfate.~ and rate of pore plugging.

The testing conducted by the Germans found catalyst deactivation and blinding occurs

when firing coals with lignite Or brown coals thot have ashes that are rich in alkali ano

alkaline-earth elements..
The findings hy Ihe Germans Were confirmed by reccnl SCR catalyst slipslream

lesling that .howed significanl evidence of ~odium and calcium-rich sulfate forrnaliun

lhat fill amI plug the eatalysl al both Egoi te- and subbi tuminous-coal-fired power

planK The resuhs of[hi~ recent tcsting showed Ihallllc pre.,ence ofsodium

si.[,'ni ficanlly CIlhanced Ihe fOITnalion of bonding 0 f parLicies and mOre rapid suH:llion,

filling of pore.", and rapid inneaHe in pressure drop across the eaLalysL

• DeposiL carryover, or ··popcorn >L,IJ," plllgging lhe top ofLbc SCR calalyst is n

signif,canl problem because of the eXlremdy bigh deposilion rales o[lhe Cenler coal.

\Vhen [iring Center coal, deposits fOITlI 'On various parts of Lhe boiler retl"iring

conLinuous soolblowing_ The soolblowing of upstream heal-exchange e'luipmenL will

cause deposit Irngmel1ls Lo be carrioo back to lhe SCR enlalysL, resuHing ill plugging.

In addition, during soolblowing 0 f the SCR eatalySI, Ihe enlrainJllenl ofdeposit

fra!'.Jllellls along wilh 1be soolblowing media will rt,"lllL in signiJicanl erosion ofthe

catalyst slIrfaees.

• Reeemle,ting with subbilllminous ~nd lignilic coals indic~lcd a signifieanlly higher

level orpore filling nnd plugging in the c~lalysL exposed to lignile asll as compare [0

sllbbilllminous coal ash_ Tbe cal~[ysl pores as well as thc catalySI surface 1Il the lignile

lesls were complclely coaled wilh a sodillm calcium sulfate m"leri~l, while only pore

Jilling was fOllnd in Lhe subbiluminous co"llesling. The pressure drop aCross Ihe

calalysl exhibited for lignite was 4 Lo 5 limes gre~tcr Ihun 111"lloll",1 Ii,r a ci1lalysl

exposed to snbbituminous coal a-,h_ The plugging "ccllned OVCr a 1000 hOllr tcsl

period.

:r Cold Side SCR Installation

High-sodium lignile co~l from the Center Mine Hagel A and B s~am coal produces

signifkant le"elH 0f homogcncollHly condenscd sodilim sui fale Ihal pass Lhrough Ihc ESP

mul weI sembbcr_

Thesc small particles have b~en shown to pass tbrough " wet scruhber and will

accumulnle 00 surfaces oflail-end SCR systcms_ The accumulaled materials require

sootbJowing 10 remove thc particul"le and will resull in inclcased "pacily.

• Liquid pyrosulf~ tc materials at lemperalure, as low as 5J5"F Ji-"m sodium HlIl fate materials

Oeeun; in coal·flrcd power syslems and is well documcnled_ Pyrosulfate.s will fonn and

emlse blinding oflail-eml SCR dcvices_ In addilion, SCR syst~ms arc knoWJl to c~tilJyZC

lhe. fonn~lion ofSO) from Sal. Th~ presence of SO, significantly enhanccs the

[ornmtion "flhe pyrosullales_

_'c
ASH IMPACTS ON SCRCATALYST PERFORMANCE

INTRODUCTION

Ash produced during combustion of coal in conventional powersystems is a major

problem that results in decreased ellicicncy, nnscheduled ontages, equipment failures, and

increascd cleaning_ The many ways in whieh!hc detrimental effects of ash manifestthemselvcs

in a boiler system include fireside ash deposition on heat-transfer surfaces, corrosion and erosion

of boiler parts, poor slag flow, and production of fine particulates that arc dimwit to collect.

Decades ofresearch have been conducted to develop a beller understanding ofilie chemical and

physical processes ofash fommtion and deposition in combustion systems_ Overviews of ashrelated issues and compilations ofwork by many investigators can be found by referring to the

work o[Mehta and Benson (I), Schobert (2), Baxter and DeSoliar (3), Couch (4), Williamson

and Wigley (5), Benson and others (6), Benson (7), Brycrs and Vorres (8), Raask (9, 10), and

Benson (II). This work has led to a detailed underslanding of ash formation and behavior in

combustion syslems as well as the development of predictive methods (12, 13).

The chemical composition and physical characteristics of ash-fomling or inorganic

components (mineral and organically associaled elements) oflbe fnel(s) fired have an innoence

on tbe following processes in the combustion sySlems:

Transformalions of coal inorgnnie components to ash particulate and vapor-phase

species

Boiler design charaCleriSlics, including number ofbumers, radiant section area, lube

bank spacing, access for cleaning, and number ofsootblowers

> •

'" • ".cc

'"

• Ash transporlto heat-lransfer surfaces in utility boilers

• Erosion wear and Slicking

• Ash deposil growth and impact on he"tlransfer

• Ash blinding and plugging ofselective catalytic reduction (SCR) catalysIs

• Ash deposit removability

The ash deposition in North Dakota lignite-fired power planls is a major problem that

impacts all fireside surfaces oflhe powerplanL The ash problcms arc due to the variable and

complex nature oIinorganic componenls associated with lignile coals (2). Upon combustion, the

inorganic compon...nL~ undergo chemical and physicallransfonnations lhal produce intermediate

inorganic species in lhe foun ofinorganic ga.<!<>;, liquids, and solids_ During the gas-cooling

processes in the boiler, ~le gas-phase species condense and the liquid-phase materials solidify.

The abundance ofthesc gas-phase and liquid malerials enlrained in the bulk gas now is highly

dependent upon coal composi tion and system operating conditions. Thc inorganic materials are

lmnsported to heat-transfer and calalyst surfaces hy diffusion, electrophoresis, lhermophoresis,
and inertial impaction. The particle sticking and accumulation rutes are dependent upon the

quantity ofash and the abundance ;md viscosity ofthe liquid-phase components. In hightemperature regions of the boiler, high·temperature sodium-caleium-aluminosilieate liquid

phases aeL as the sticky material, causing deposit initiation, growth, and dcvelopmcnt of deposit

slrength. As the tempera lUTe ofthe nue ga"es decreases, the comlen,alioTl and reaclion of namevolalilized species playa more significant role in the fomlation of deposits from lignite coals.

The f"llllaLion ofsodium and/or calcium nmgnesium sulf..ltes dominates the deposit

acculllulaLion mechanisms at lower temperatures. The aluminosi Iicate phases are dominant above

aboHt j SOOOF. Below ahout 1R(JO°F, the ,u]fale pha,es heCtlllle ,table, with an oplimum

LemperaLure offomlation of about 1400"1', and can foml at temperaLmes as low as 300°F.

The most significant problems that prohibit the successful operation ofSCR catalysis 10

[igni Le coal is the formation oflow-tempcrahlre sodillm-calcium-magllesiuJIl suIJnles and

phosphates that will limn on the surfaces ofcatalysts and the carryover of dcptl~ilS thm will plug

the catalYSI openings, resulting in inereased preSSUfC drop and dccreased erIiciency ( 14--1 6).

INORGANIC COMPOSITION OF LOW-RANK COALS

Inorganic elements in coal occur as tliscrc!e minerals, organically associated calions, and

cations dissolved In pore waler. TIle Ii-aelion 0 r inorganic components thal are organically

associated varies wilh coal mnk. Lower-ranked suhhitulllimllls amI 1i~'1lillc coals have high levcls

of oxYflen, which acl a~ h<lmling ~ites [or calions such a~ sodium, magnesium. calciulll,

pola"ium, strontium, and balium (Olher minor and trace e!emenls may also be prcsenl in lhis

form). In higheHanked coals, bitllminolls and anlhracite, inorganic components consist malnly

,,[minerals. Miner'll grains are uoually the most abundant inorganic eomponenL in coal. The

major mineral groups found in COols include silieatcs, aluminosilicates, carbonaLes, ,,<Ifide;,

"ulfales, phosphates, and some oxides.

The behavior of ash produccd during coal combnslion is rclaled to the abundance, size, and

associalion of milleral grains in the coal. In addition, tbe association ofthc minerdl grain wilh the

coal malrix innuences the temperature and gascous environmcnl the mineral is exposed to during

combustion. A mineral associated wilh the organic parI of a coal particle i, said to be included. A

mineral that is nol a5sociaLed with orgaoic malerial is referred lo as excluded. The behavior of

Lhe orgallically assoeiatcd elemcnts, Lhosc demenlS thaL arc alomically dispersed in the coal

matrix, must also be measured as to thcir ahundilllce in the coal. The organically associated

elements will read ami interad with the other ash-fomling conslltuents during eomhuslion.

The Cen Ler lignile is highly variable in abundance of various types of a~h1s1ag-[tllllling

consli tuenls. Ash·Ionning components in the Center lignitc are of 1\\'0 typcs. The liml [onn may

cOllsti tutc lip to SO% 0 f thE a,h and is derived from inorganic elelllenLs (sodium, magnesium,

ca1cinm, and potassium) associaled wi Lh oxygen fllnclional in the organic matrix 0 [lhe coal. The

second lype consists of mineral grains (sand, clay, limestone, and pyrite). The minerdl, are

discrete partides of ash-forming spccies <tud the sources ofsilicon, aluminum, iron, lilanium, and

minor amollnts uflhe ca1cinm and ptlla,sium. The Cenler lignile fired aL the MilLon R. Young

(MRY) planL has been examined extensively bec~lIse ofits problem with ash behavior. Analyses
of as-fired and drill core samples have been conducted. The mean and the range ofselected

components are shown in Figure 1. The resulls indicate that botb tbe abundance of ash and the

abundance of major oxides in the asb vary significantly. In addition, the abundance of alkali and

alkalIne-earth elements (Na and Cal varied dramalically. Variations in Si were found to be the

most significant. High levels orCa "nMor Na were found for lower-ash coals as compared to

high levels of AI and Si .ssociated with bigher-ash coals (17, 18)_

00

, 00 !

•

,'" 0 00

0

"

00 ---- ---- ----- - ~-~~ ~~

----- ~~----

"

--"! 40 ----- ~~ ~~

•

. '" ,

" i Woo

I ;f I I I ! 00 i

" , , , , , I ~,

- ~. 00 ~. "". ,,",0- .,. Slo,·

- ........'" - ....base

- """,base- ._. -- """",,,,,,

Figure 1. Variability of ash and selcctcd constituents in core analysis database provided by

BNI CoaJ;'Ltd_ and Minnkota as fircd coal analysis database.

The variability ofthe asb-forming componcnts has been examined for the approximately

5000 'aInples characterized to date_ Wide variations in ash contenl.s and the major asb-forming

constituents are observed_ During the mining processes, the inorganic components are mixed,

and some ofthe extreme chardcter!slic, are diluted (17).

INORGANIC TRANSFORMATIONS AND ASH FORMATION

Thc inorganic coal components undergo complex cbemical and physicaltransrormations

during combllStion 10 produce intermediale ash specics. 'The inorganic ~lIecie:; consist ofvapors,

liquids, and solids_ The partitioning ofthe inorganic components during combustiou to form ash

intennediates depends upon tbe association and chemical characleristics ofthe inorganic

components, the physical characteristics ofthc coal particles, tbe phy,ical chanlCleristics of lhe

coal minerals, and the combustion conditions_

The physicaltransfonuation orinorganic constitucnts depends on the inorganic

composi[ion of the coal and comhu,tion conditions_ The inorganic components cnn consist of

organically associated cations, mineri11 grains thai are included in coal particles, and exeluded

mineral grains. There is a widc range of combinations ofmineral-mineral, mineml---cual,

,
mineml--calion--coal, and mincrul--mincral--cation -coal associalions in coaL These a'Socialions

are uni'lue 10 each coal sample.

Thc ~hysical lransfnmmtions involved in Ily ,,-,h formation include I) coalescence of

individual mineral ~ins within n char pnrticIe, 2) shedding oflhc ash particles from thc surface

ofIhe chars, J) incomplclc coalcscence l!ue 10 disinlegration oflht: char, 4) conveclive transpOlt

of ash from Ihe char surfa~~ l!uring l!~volatiliznlion, 5) fragmenlation of lh~ inorganic mineral

particles, 6) formnlion {) Lc~nospheres, and 7) vaporiznlion and subse'luenl comlensatiOJl ofIhe

inorg~nie eompon~nt" llPOn gas cooling. As a resull oflhese inleraclions, the ash h~s a bimodal

size dislrihution. The Sll bmicron componenl i, largely a reSlllt of the condellS~tion of flam~­

volalili:t.t:d inorganic componenls. The mass mean diameter ofthe lnrger pnrtielc, is

approximately 12 to 15 ).1m, depending upon lh~ coal imd combuslion condilions. The larger-size

parlicles have been called Ihc residual ash by ~0111e inve5tig~tor'(19) hccau,c lhe,e ",h particles

resemhle, to a limited dcgret:, the <>riginal minerals in lhc coaL Pmce",,-, such a, ash mineral

coalescence. pm1ial coak,cence, a,h shedding, and char liW,'TI1enlatinn during char eombuslion

and mineral fragmenlalion, all play an important role in lhc size and composi lion ofIhe final Ily

a,h. I ,0ehdeJl and olhclO (20) and 7.ygarlicke and othcrs (21) indicale lnal lhree potenlinl mOlles

for fly ash generalion can be u,el! 10 describe fly nsh particle-size and composilion evolulion.

The first, '"fine limil," assumes that each minernl grain fonm a fly ~sh particle and Ihallhe

organically associaled e1emenls form fly ash parlicles ofJess than 2 ).1m. The second, "Iolal

eoalcsccnce," assumes one fly ash particle forms per coal panicle. TIle lhird, "parti,jj

coalescence," 'ill ggests th~t the 11 y ~Sll eomposiIi oil 000 particle size cvolvc b ceau",e of portial

coalescence.

The translonnalion, of excluded minerals nrc dependenl upon Ihe physical characlerislic.,

ofthe mineral. Exclul!ed minerals such as (juartz (SiO,) can be canied lhrough Ihe combustion

syslem wilh its angular slruclure still intact. Excluded clay minerals can frag.ment during

dehydratioIl, mell, anu fonn cenospheres. The hehuvior 0 r excluded pyrite depends upon jls

morphology. Some oflhe pyrile may be prescnl as fulmboids. Frnmboidnl pyrite may fragmenl

more casily limn ma."ive pyrite particles. In addi [ion, the decomposition of pyrite is very

exothermic, and illmnsfomls 10 pyrrllOtile and oxidizes 10 FeO, l'eJO., and Fe,O.ll!ming

eombustion_

ASH DF:POSJTION ON HEAT-TRANSFER AND OTHER SURFACF.S EXPOSED TO

ASH AND FLUE GAS

The characleriSlies of a deposit dcpcnl! upon lhe chemical and physical characleriSlics of

lhc inlem,,,diale ",h species, geomelry ofIhe syslem (gas How paUems), ga, lemp=tllrc, gas

composition, and gas velucily. Figure 2 illuslrates lhe a,h deposilion phenomena inutilily

boilers. Ash purticle accumulalions occllrvia tramport ofp~rticles [0 lhe {ireside surfaces (heat

lransler, ceramic materinls, support malerials, SCR catalysts, bnghouse materials, and ESP wire,

and plale.,) and Slicking ofthe particleS. The lransport mechanisms imporlant for ash depo,ilion

include sm~[J-particicmechanisms for particles less lhall 10 1'm Ihal involve Iherlllophoresis,

electrophorcsis, and vapor-phase and smaH-partic1e di [fusion; and large-particle mechanisms 1"r

particles greater lhan 10 ItIII that involve incrtial impaclion. The abiElY oflarger particles lO ,tick

l!epcmls upon lhe quanlity and viseosily oflhe liquid phnse on the parlicle 'llrface.
Thermophoresis is a phenomenon Lhat involves the transport of very small parLicles as a

result of "- Lhermal gradienL from hoL gases Lo cooler surfaces. Electrophoresis is lhe transport of

pnrticJes beeaIl.~e ofa difference in charge. Vapor-phase and small-particle difTusion occurs in

the boundary layer next to the surface and results in lransport of ash to the surface. lnerLial

impaction is a larger-parLicle phenomenon wbere Lhe particles are of a sufficient size and density

to leave airflow patLerns around the Lube and impinge upon the surface ofa Lube or deposit.

Deposits thal form in high-temperature regions ofthe boiler, such as Lhe radianL secLion, are

called slag deposits. Deposits Lhat form in lower-Lemperature regions ofthe boiler, such as in the

convective pass on steam tubes nnd lower-temperature surfaces snch as SCR eaLalysls, arc called

fouling deposils. Slag deposits arc usually associaLed with a high level ofliquid-phase

componenLs and are exposed to radialion from the flame. This is a description Lbat many

researchers usc Lo aid in classification of deposits since some engineers call any Lype of deposil

"slag". Slag deposiLs arc LypicaJly dominated by silicate liquid phases, but may also contain

modcrale to high levels ofreduced iron phases such as FeO and PeS. The liquid characteristics of

the sj1ie~les are highly dependent upon the quantities ofNa, Mg, Ca, K, and Fe ash on the

silicates. In mIdi lion, the in.itiating layers ofslag deposils may consisL ofvery fine particulate and

can produce a rellectivc ash layer. This phenomenon is especially evident when high organically

associaLed calcium subbiLuminous coal is fired. These coals produce small CaO particles lhat

usually form lhe initiating layers.

--, Fouling deposits form in the lower-Lemperature regions of the boilers and, in most cases,

do·no t con min the- high-levels of-liquid phases thaL are usually assoeiaLed wiLh slaggiug-tJ1lc

deposils. Fouling deposits contain lower levels ofliquid phases rul compared to slag deposiLs.

The fouling deposil liquid phases usually consist mainly ofsulfaLes that bind Lhe particles

Logether. Fouling deposits typically fOlTIl as a resull ofthe reaction ofgas-phase sulfur oxide

specIes with panicles rich in alkali and alkaliue-earth elemenLs.

ASH-RELATED EXPERlENCES AT MRY FACIJ,TTY

The MRY is a minemomb elecLrical generating plant located near Cenler, North Dakota.

The slalion consisLs oftwo uniLs: Unill, rated aL276 MWg, began production in 1970; Unit 2,

rated al 506 MWg, began prodnction in 1977. Both UniLs I and 2 are equipped wilh B&W

cyClone-fired boilers; the Unit 1 boiler has seven cyclones, and Lhe Unit 2 boiler has twelve

cyclones. Annual sLaLion gross generaLion is approximately 5_5 mjJJion MWh.

BNl Coal Ltd. is Lhe sole coal supplier for Lhe MRY Station. Coal is mined from Lhe nearby

CenLcr mine, which consists oflhrec disLincl seams varying from 2Y,-9 feet thick. Coal is snipmined using two draglines and is loaded with fronl-end loaders and delivered Lo the planL with

bollom-dump haultrncks. Annual coal producLion is 4.3 million tons per year.

,
,0

•

I

•

• $, • , , ' . • ->

00

•

> .-". "' , • " 0 0 , • • '0 £ • '. • >, .~ (;) • , • ".o. • 0 • 0 • •

c

"

,

0

0

•

"

,

,

-

1

,

rf\

•0

!

, .-

,

"

0

5.!:!E ~oc:

0

Eu2 ."

0

E·2!, ,,"':;

6

t

.0•, ":.='" .., ,

E

"0• "_ 0

'" ." ...

" h~ ~~

" 0' .' .lq: 0 • •0"• ,o • --" e- O [l':gc:

..'

0

,,"'" :;;

0

'0•

'"

:0-.

IP-",E • c: Ci

-

•

-

- €i,'5 "-

0+·- -. -.'S

(~

h

0

••••

iiI

"0•

--Q

,

0

"

0

,'- '.

0

e &~

--0 ,~ o. 0 - o'

.,

0•

"

•

."

••

•

0a-"0

,

-•

,

0

•

,

,

•

"' "~T

0 u.

0

•

"UbaI ~H"

,

0 ,/\I -.

• ". ,

• ""~

l

0 ,.

,

"

" .' • 0"

E

,

0 >'

-

0 .,• • ••
'''-

Hislory of Furnace SlaggingIFouling

Prior 10 1991, be8ides annual maintenance outages,load reductions and forced oUlages due

to furnace slagging/fouling were the largesl caus~ ofproduelion loss_ In 1985, opending

guidelines were established that reduced furnace slaggingifouEng, including deslagging outages

scheduled every six months.

In 1991, a 3-molllh hoiler cleaning cycle was propnsed llnd initiated. The goal oflhis

program was 10 increase annual generation by running lhe unils al higher suslained loads and

scheduling boiler"cleaning outages at 3-monlh intervals_ However, fumac~ slagginglfouling

continued to have n significant impacl on plant operations. Success was mea,moo in the number

ofproduction days botween boiler-c1~aning outages.

During the mid-1990s, a major outnge every third year was scheduled for each unit. In

addition, Unil 1 c1enning 0I1tages were scheduled for SD-90-day runs (four cleaning oUlages per

year), and Unit 2 cleaning outages were scheduled for 65-75-day runS (five cleaning outages per

year). The problem was that furnace amI convection-pass surfaces graduaIly become coated with

ash deposils, which, over time, sootblowers cannol remove. Some ofllle contributors to the ash

deposils were as rollows:

• Organically associated sodium is a primary contributor to deposition problems. Sodium

is vaporized in the cyclones and condenses on other ash particles, causing them lo

becom~ slicky and deposit atlhe furnace exit. lbe problem is associated with sulJale

fornlation and occurs in the convective pass, including the economizer. Sampl~s show

that sodium in the ash varies from 0.60/.-13.0%.

Organically assoeialed calcium is another component that causes deposition

problems. Unlike sodium, calcium does nol prodnee a vapor-pha,e component.

Calcium does react willi silicate (derived rrom clays) to cause low-melling-point phases

thaI produce wall deposits and deposiLs in the high-lemperature regions ofthe

conveelive PiISS_ Calcium also prod'ices very small particles that will be transported 10

heal-transfer surfaces, resulting in the fonnation oflhin, light-colored layers caned

reflective ash. These small particles ofash arc carried through to the back passes where

lhey are sulfaled and can combine wilh sodium to cause the formation ofslrong\y

bonded suI rate-based deposits_ Samples show that calcium in lhe ash varies from 6.80/.-

24.0%.

• Clay minerals and quanz - Center lignite can contain higb levels ofillite, which has a

1:3 AJ;Si ralio and high levels ofpotassium, both ofwhich cause wall slagging and

high-temperalure fouJing_ Quartz and otllCr clays can significanlly conlribule to the

mass ofthe deposilS. Samples show thaI ash contenl varies from 5_00/.-25.5%.

Advanced Boiler Performance Indices

Advanced indices are useuto relate Ihe coal characteristics as determined by computercontrolled scanning eleelron microscopy (CCSEM) and chemical fractionation 10 ash behavior in

a coal-fired uli lity boiler (12). rUel perfonnance is estimated in lenns ofslag [Jow behavior,

,
ahm,ion and erosion weHr, wnll ~Iagging, high-Lemperalure .,ilicale-ha~cd convective pass

fouling, and low-temperature suifate-hased convective pass fOlding. The following indices are

llSOO 10 asses~ the effects 0 f ash behavior on \ILilily boiler perfommnee:

• Convective-Pass Fouling indic",,"

Sui ration lndex: Indicales Ihe pl'Opensily ofdeposil lO form in Lhe eonveeIive pass of/he

ulilily boiler in the lemperature range Ii-om 1000Q-I 750°F_This index is ba~ed On lhe

availahility of alknli (Na and K) and alkaline-earth (Ca and Mg) e1emenL' to reacl wilh SO,

and SO) 10 limn sulIHles. The sulfales ore the primary materials that cause pmticle-Ioparticle bonding in high-calcium coals. The su [[hies arc thcnnodynamically sLable at

lemperalures below abOUI1650°1'.lndex vallics range from I (low) 10 lU (severe).

Silieo ~e 111dex: Jndieoles the propensity ofdeposi l~ to rorrn frum 1600" ·2400°F. This

index is related 10 Ihe fonnation of depusilS in which lhe sihcale malL'Tial i~ the primary

componenlllwi bonds Ihe deposits togelher_ The informalion u~ed to derive the index

inehldes Ihe size ofthe minel'~ls sLleh as q unrtz and clay minerals, availability "f alkali ~nd

~lkalille-eaJ1h elemenls, ~nd viscosity u r the silicale liquid pha8e. Imlex values rallge from

I (low) to 200 (seYcre).

Walerwall Slagging

Siagging Tndex: Indicates lhe propensily of a deposit to foml on the radianl walls fwrn

2000° 3000°F. The b""i8 0 f the slagging index is Ihe size oflhe minerals (espceially lhe

illi le, qllal1z, and pYJite), a8soei~lioll ofIhe calcium (calcile can contribule to slagging),

".\1([ viscosity oflhe silieale-based liqllid plmse. Index v~lue" range Ji-om I (low) Lo 20

(severe).

• Wenr Indices

Abrasion IOdq: This index indicates the potenlial for wear offilel preparalion and

handling equipment. The ,,,,ar is relaled 10 Lhe hardness of minerals in the coal. The

primary minerals of eOn~em include quartz and pyrile. 111e index v~lues range fi'om 0.1

(low) to 10 (severe).

Erosion lmiex: Thi.'> index indicates thc polentjal for wear ofhuilerparts due to Ihe

impnetion offly ash pat1icles. The ew~ion jndex i~ dependem upon Ihe ~ize oflhe

ash}mi\leral particle, size ofthe pm1icle, and velocity nf lhe parlicle_ The index values

range from 0_] (low) 10 1.0 (severc).

Cyclone Slagging Index: This index provides informalion on Ihe slag now behavinr in

cyelones_ The fnelors lhal are included in Ihis index include the pnrtilioning oflhe ash in

Ihe ~yelone based On size and assoeialion oflhe ash-forming componenls in Ihc coal.

The partiLioning onhe ash belween Ihe slag and entmined ash can 8ignificantly

inf1uenee the now heha"ior ofthe sing. Slnndard partitioning ctileria have been

developed lO provide the composilion onhe ~Iag_ The composilion is used to estimate

lbe visco~ity "flhe slag ~s a function of tempemture. The index vahles hnve severnl

ranges as r"l!nws: 1 (low vig~o"ity). T.5-2.5 (oplimllm viscosity), >3.0 (sing frce/.ing).
~. I ~,

1-11 ".i.

I"

~.,

• Slrength Developmenl Index: 1be slrenglh index is based on the ability oflhe deposited

material 10 develop slrenglh_ Strength development is primarily dependent upon lhe

abundance and viscosity orthe liquid"phase componenls in the deposits_ Index values

jess than 0_25 indicate thai the material will produce weak deposiu;; index vahles of

0.25-0.34 indicate weak-lo-modernte-strength deposils; index values of 0.34-0.41

indicale high-strenglh deposits; and index values >0.41 indicale flowing slag_

Indices were calculaled for a range ofcoals from lhe Center mine, and the propensity for

ash deposilion in various portions of the boiler indicates wide variations, as shown in Table 1.

The BNI numbers indicale the location in the seams where lhe coal originaled: Kinneman Creek

se;,m (KC), Hagel A (HA), and Hagel (HB). Each seam has a differenl distributioll ofminerals

and organically associated clemenls IhaL can have a significanl impact on lhe fOnJlation nf

deposits in lhe systcm_ Compnrisoll ofCenler lignite to subhilUminous and biluminous co<lls

from otber regions ofthe United States, shown in Table 2, indicales significant differences in the

polcllualto fOnJl dcposiLs in the boilers_ In all cases, the lignite (not lhe wors/. coal from CenLer

mine) from tbe Cenler mine has a high propensily to produce deposils as compared 10 the other

coals.

AnoLher indIcation oflhe variability oflignites can be illusLrated based on the calculation

of Lhe lemperalure where the slag flow would occur. This is defined as lhe T250 lcmperature,

where the slag viscosIly is 250 poise. Frequency dislributions ofLhe T250 values for a1l1he data

for coals analyzed are Illuslrated in Figure 3. Calculations ofT250 values for 1212 samples

obLaine'dTrom the Cenler mine database (17) were made using empirical relalions derived from

CCSEM aud chemical fraclionation data and knowledge ofhow ash partitions in lhe cyclone_

Figure 3 shows a bimodal dislribution in the T250 b,,-~ed on lhe Urbain equalion calculations_

The primary mode was at a value 0[2000°1'. The secondmy mode was at abOUI 2700°1'. The

results indicale lhal many oflhe coals have a sufficiently low T2S0 for good slag now. However,

coals with T250 al 2700°F arc not. suitable for maintaining good slag flow.

Figures 4 lhrough 6 ilIuslrate the variaLions in T250 for the various SeamS ofcoals

characlerized. The HA and HB seam coals appear 10 have large numbers ofsamples, wilh 1'250

values at or near 2000°1'. The KC scam coal, as illuslraled in Figure 6, has extremely high T250

values. Based on Lhese data, the KC coals are not favored relative La Lbe slag flow behavior oflhe

ash.

Frequeuey distrIbutions of cyclone slagging index values indicaLed significant variations in

slagging poleutials ofcoals mined from the lhree seams, KC, HA, and HB. This infonnaLion

proved particularly useful in planning Lbe mining and firing of coal from the KC seam_

During a July 1999 test bum, lhe composilion oflhe cores was used 10 examine and

iJluslratc lhe variabilily ofthe delivered coal qualily based on base-to-acid ratio calculated from

the asb composition. FIgure 7 shows lhc variation in Lhe base-lo-acid"ratio and the seam where

the coal was loaded_ The base-la-acid rdtios were calculated from core di1ta Lbat corresponded to

the location in lhe seam where lhe coal was mined. There is a signifieaut variaLion in !he base_

lo-acid ratio for the coals. The coals lhat have lhe highest base-to-acid ralio are Lypically from

Lbe HA seam_ HB scam coals generally have an imermediate base-to-acid ralio. KC or top-seam

coal has the lowest base-lo-acid ratio_ Lower base-to-aeid-ratio coals lypically produce slag wiLh

high viscosilies.

"
<"

,,

,,

, ..

,

, .. ;:': , .. , .. c ,;" 0 , "

" ..

0

,

"

- ..

0

,

-

•

-

00

0,

0

,

,

0 ..

•

-

00

-,

0

" '0 00 '".,

•

,-,

-

,

-

-

-

" ,_. ,0 ". '<'

• --.

- ..

"-

,,

,, ,.- .. 0 • 0 •

o. i~

0

"

0 -,

0

,,

0

"

, ..

,

,

,

, .,

0

-..

"

0

, ..

'" '"",-, '" ...,

0,_'" ,., '0''"

""_

"'o~~ ,,' '" ",,,.,00

, -- 2 ,,:;:l ,..

,

-.. ,-

, .. '.,- '0 ,,.. " ::' .. 0 0

--

"

•

-

,

-

..

, .. ,-. .. .. ,

;::, ;C

g

,..

: ..

0 .. ..

,

-

c

"

, ••

0

"

,

0 .. ..

0

" --..

0

.."

0 ,-

,

,

0

, c,

0

,

,

" ,- , ,- " 0 .. ..-, , .. .. , , - .. .. ..

-

-

- ..

..

•" ,S~ ..

,

"

"

• ..

,

"

-

,

0

0

,

" ...

0

-

I

-

""

-

,

"

0l

•

"

,

"

"

, c, 0

.. -, 0 .. " •

, --

-..

0

-

-

-

-

-

-

-

•••

,

,

,

-•

--

, ..

.. ,,,

,,

, ~;'~8:;; ooo __ ~_

~.,~O

~~, c, 0,.."'''' C, M...,_

,,
Table 2. Advanced Indo Values for Other Coals (12)

AdV'lIlted lndices

Cyclone Slogging Index

ConveClive ross Fouling

Silica,e

S"l[ale

Wall Slagging Index

Erosion Index

Ab..,iun Index

Lignite

NOrtil Dakota

61.8

4,09 '2.

0.15

0.71

Powdor River Basin

"

23.99

2.88

'-85

0.17

1.96

Bilumino,",

Illinois

10.]6

o

'-53

0.14

3.94

Bituminous

Appalachian

"

14.2 I

1.66

"

0.17

1.96

"

,'." ;)

:<' , "

", I l

"

, , , , , , , ~,

, ,• } , ,

,

" ,. , < >i .', , , a a a a a a a a a a a a a a

a

• 8 a a a a a

"

a a a a a • N " • • , • • a , , N N N N N N N N N N - " " Temperature, OF

<C,

,.

"

"

;g, "

'"

u ~;

" C

fi ,

• •

,

" ,

• " ,

,'0·.

, ,•

•

, ,.

..;

\0

0

a a a a

a a a a

!;/ • • • ,

-

Fil!:ure 3. T"o frequenoy distribUlioll for all.Coal Quality M"ll"gcmelll SySlem (CQMS) daLa, °F.
w

,

8

,

0 8

c

ID

0 8

e ,

8

,

,

0

:>,

, , , , " it ."; 'j :; i- t. -< j

" , ~i_

, t

;! 'i' ',~ ~~

,

-~ If' ,. , 1, , ;

" f! R"

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

• " 0 , 0 0 0 - 0 0 , " 0 , ro 0 0

- - - - - - - N N N N N N N N 0 0 0 0

Temperature, of

Figure 4. T1lO diSlrihution ror HA seam CO'll.

c,

Temperature, of

o

8

o

Figure S. "11>11 dislriblLlion for HB Scam COllI.
10

,

,

,

0 6

c

•

" 6

rr

• ,

'", '

, !i

,

,

"

I

""

0 , 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0

" 0 0 , • • 0

- - " " - - - • " • •

,!

;

,

i;i

"

o 0 o 0 o

" "

'.6

'.0

TI

"0

"

L6

•

0

ro

w , .0

Temperature, OF

-- -- Fig ure 6.--T'50 -distribution-for KC -seam coal--

Figure 7. Variations in the delivered coal quality during 1I tesl bum period.
Figure 7 shows the sequence of deliveries beginning on July 6 ami ending on July 12,

2004_ During (his period, (he mf\jorily orthe coal delivered wos fmm lhe llA scam, roll"wed hy

KC, and liB. Mosl ofthe deliveries allemate<i belween KC nnd HA- Figure 6 shows several

iJl~t~nccs where sigllifiennl qunnlilies ofKC coal were delivered, on Jlily 6 through] lily 9" The

lJunntily ofKe coal delivered will have the polcnlial to increase the viscosily ofthe ",lag and

re.sull in poor slag now from the cyclones.

ASH-RELATED IMPACTS ON SCR CATALYST I'ERFORJ'dANCE

Ash-rclnled impncls on SCR ealaly~l per[omlallCe will depend upon the composition ofLhe

coal, the lype offiring syslems, nue ga, lemperalure, and ealnlysl design (14-IG, 22) Thc

problcms cllrrenlly being experien~ed "n SCR catalyslS includ~ the J"Il"Willg:

Formalion ofsuifale- and phosphate-based blinding malerial, on lhe sUJ'fnec of

calaly"~ls.

Carrying ordep()~il fragments, or popcorn ash, from olherpa,ts oIlhe boiler amI

del""iling on lop 0 r the SCR c~t~lysls.

J.icata and Olhers (14) conducled tesls on a Soulh Afric~n and German Ruhr coal and

found Ih~llhe Gelman Ruhr coal signilieanlly increascd the prcssure drop n~ro"" the catalysl

beCallSC of the accumulation of ash_ They roumllhalthe German coal produced highly adhesive

ash consisting of alkali (K and Nn) suIfales. In mldilion, lhey reportcd thal Ihe alkali clemcnls are

in water-solublc form and highly mobile and will migrate lhruughoutlhe ci1lalyst malerial,

reducing ~etive siles. The water-,oluble fonn is typical 0 r organically associated alkali clements

in coals. The German Ruhr Valley coal h~s abolll 9.5% ash ,md 0.9 % S on an asre~cived hasis, and lh~ ash consisls mainly o[Si (J8.9%), Al (23_2%), Fe (l \.6%), and ea

(9.7%), with lower levels ofK (1-85%) and Na (0.85%) (l5). Cichanosicz and Muzio (1G)

summarized the experience in Japan and Germ~ny and indicaled lhal the alkali clements (K and

Na) reduced the acidity o[lhe catalyst silcs lor lolal alkali conlenl (K+Na+Ca+Mg) of80/0-15%

oflhe asll in European power plants. They also lonnd (hal ~lkaJine-earth clements such as

c~lcium re~ct wilh SO) on lhe cal~lyst, ","ulLing in plugging of pores and a decrease in the ability

ofNil) lo bond to c~telysl sites. The levels of ~aleium in the co~ls thm catL'oo blinding ranged

from J%-5%ofthe ash.

The mechanisms for lhis lype oflow-lempemlUJ'c deposilion have been examined and

mo<ieled in delail allhe Energy & Environrnenlal Re:;e~rcb Center (EERC) in work tenned

Projecl S"dium and Projeel Calcium in lhe early 199Us; however, the focus of lh"se projects WeS

specific 10 prim'lfy superhealer and economizcr rcgions ofboilers and nol SCR syslems (22, 23)_

Deposit buildllP ofIhis lype can cITcclively blind or ma,k the calaly~l, diminishing ils n:"activily

for convening N02 10 N2 and wnlcr and potenlially crealing increased ammonia slip (14)_

Arsenic and phosph~les, which arc nol Uncommtln in low-rilllk coals, may also piny a role in

ealalysl degencralion. Arsenic is a known c~laIysl poison (14) in "pplicalions such as c~lalylic

<lXi,bli"n rorpollutioll control.l'hosph"tes c~n occur in low-temper~lurc ash dep"sils 10 crealc

blinding dTecls, and lhcy also OCcur with arsenie and e~n cnusc c~talysl poisoning (2J).
Lignite and suhbituminous coals produce ash iliat plugs and blinds catalysts (25-28)_ Thc

problems currently experienced with SCR catalysts includc the formation ofsulfate- amI

phosphate-based hlinding materials on the surface ofcatalysts and the carrying of deposit

fragments, or popcorn ash, from other parts oftbe boiler and depositing them 00 top oftbe SCR

catalysts (14). The most significant problem that limits lhe successful application ofSCR

catalysts to lignitc coal is the formation onow-temperature sodium--ealcium-magnesium

sulfates, phosphates, and possibly carhonates thal wlll fonn on Lhc surfaces ofcatalysts and the

caTT)'o~er ofdeposits that will plug the catalyst openings, resulting in increase<.! pressure urop

and decreased efficiency (14-16, 27-28). The degree oflbe ash_related impacts on SCR catalyst

performance depends upon the composition ofthe coal, lbe type of firing systems, flue gas

temperatnre, and catalyst design (15--16, 24, 27-28)_

In studies (7) the impacts of tempernture and the presence ofcatalyst on the ability ofash

to sulfate were examined_ Thc tests were conducted using a thermogravimetric analyzer (TGA).

TGA testing was conducted nsing a <5-flm-si2.c fmction of ash produced from Powder River

Basin (PRS) coals and lignites aml exposing them to vapor-phase sulfur dioxide with and

without catalyst at several temperatures_ The aim of the testing was to determine lhe potential of

lhe formation ofSUlfates to cause particle-tn-pariiele bonding thnt leads to the formMion of

deposits in the tempernture range where SCR catalysts are useu_ The TGA testing is focused on

dctcnnining the reactivity ofthe <5~j.1m-asb produced-from selected PRB-anu blends to sulfur

tIioxidc and gas-phasephosphorus species as a function ofiemperature. Testing was conducted

--,,- to determine the weight gnin with flue gas containing >lmmonia. The impact temperature on the

...., weighL gain due to the fonnation ofsulfates for a PRS blend is shown in Figure 8. The rates of

sulfalion were found to increase with'increased temperature_ The results show ml increase in the

weight gains when ammonia nnd phosphorus were added_ Ground cali\lyst wns mixed with PRB

and placed io Lhe TGA. Increases in-weight gain were obsei-ved when catalyst was added as

COlnpared to haseline ca.es for 100% PRB, as shown in Figures 8 and 9, respectively. The

presence of catalyst enhances the formation ofsulfates.

Full-Scale Slipstream Testing

More recently (8), the behavior of ash and mercury in flue gas produced from tbe

C<1mbustion oflignite and subbituminolls coals from the United Slates of America in selective

catalytic reduction (SCR) sysLems for niuogen oxide remo~al has been examined. Typically,

these coals contain ash-fonning components that consist ofinorganic elements (sodium,

magnesium, calcium, and potassium) associated with the organic matrix and mineral grains

(qulll1z, c1>lys, carbonates, sulfates, and sulfides)_ Upon combustion, these coals produce ash that

has an abundance ofalkali and alkaline-eartb-ricb oJ(ide particles (<5 j.1m) that are carried inlo

the backpasses ofihe combustion system and react with nue gas to fonn sulfates and possibly

carbonates. The fonns of mercury in the flue gas produced from the lignite and subbituminous

coals arc dominated by the elemental form_ Slipstream testing was condueled at two

subbituminous-fircd power plants and one lignite-fired power plant to determine the impacts of

ash on SCR plugging, hlinding, and mercuryoxidalion_
The SCR sJipslre~m syslem consists ofLwo primary componcnls: the conlrol room and the

SCR reactor. The reactor section consists of a calalysl seclion, an ammonia iJ~cclion system, and

sampling poris [or NO. nt lhe inlcland exiL of lhe eatnlysl section. The conlrol room houses a

eompuler syslem thallogs daln and eonlrols lhe gas now rates, lemperalures, preSSlire {Irap

ncross the calalysl, and soolh [owing (.ydes. The eompuler i8 programmed 10 maiulain cO\lslanl

temperature ofthe ca la lyst, go,s flow J~tes, soolblowing cycles, and ammonia injeclion. The

eompoler is equipped wilh a modem lhal allows for downloading ordala and modificalion orlhe

operalion ofthe reactor from a remote computer localed at lhc EERC.

Flue gas is isokineticaJIy exlraclcd from the convective pas, of the boiler upstream oflhe

air healcr. The lemperaturc is typic~lIy nboul 790Q

F_ Thc nue g"ses pa,s lhrough "4-inch pipc

equipped wi lh sampling, thermocouple, and pressure ports. Ammonia is injected into lhe piping

upslreillTl of lbe rcador section. Thc reaclor con,;,ls of a slcel housing thilt is approximately

8_5 inches squure and g fcctloJlg. The reactor seclion has lhrec eomponenls, including allow

slraighlener, a pulse seclion Or soolblower, amI a ealalysl lesl section. A metal honeycomb is

u8ed il5 u 110w slraighlener upslrcam ofthe eatulysl seclion and is about (j inches long_ A purge

secl ion was inslalled ahead ofthe cUlalysl lesl seelion 10 remOVe aecumul~ted dusl nnd depo.,i l,_

The calalysl lest ,ection is localed downslream oflhe purge seclion. The entire ealnlysl seclion i,

insulaled and equipped wilh strip healers for lemperilture conlrol. The ealalysllesl Seclion is

3.28 ft (l m) i~ length und houses lhree catalyst sections. Thermocouple and pressure laps are

loealcd in the purge seclions for measuremenls before and after each scelion_

Thc induced-drafi fan is used 10 cxtract approximately 400 acfm (200 scfin) offlue gas

from lhe convee live pass oHhe utilily boiler lo achieve an approach velocily of 5.2 mls

(17.0 fVs). The gas vcloeily is similar 10 that found in full-scale applic~ljons. The lolal gas 110w

through the rca~lorreprescllts a lhcrmulload of approximntely 300 kW.

The rallge 0 f opentt;ng ~omlilions for Lhe reactor is lisled below:

X Gas lemper~lUJ'e: -700o-800~F

X G~s now rale: 400 500 adin

X Approach vdocily range: 5.0-5.5 m/sec

X Ammonia injeclion rale: 0-5: I with NO, level

X Tempering air for fan: - 50-200 selin

X Calaly,t dP: 0.5-1.0 inches waler columll

X Fan sized for up 10 30 inches watcr column

The calalyst inSlalled allhe Baldwin and Coyote Stations wa.~ lhe HaldorTopsoe catalyst.

Topsoc's DNX-seJies of calalysls compriscs SCR DENOX c"lalysls lailored to suil a

comprehensive rangc of proccss requiremenls. DNX-sene, eatnlysts are based on a corrugated,

fiber-reinforced tilanium dioxide (TiO,) carrier impregnated wilh lhe aelive componenls

vanadium penloxide (V,a,) and ltmgsten lrioxide (WO)). The calalysl is shaped to a mo~olithic

slruclure willi a large number ofparallel channels. The unique talalysl design pmvides" highly

porous slruclure wilh a large surface ~rea ~nd llIl ensuing large number of aclive sites. The pitd,

ofLhe calaly,t W>l~ approximalely (j mm.
,. ,

Thc calalysl inslalled:lt lhc Columbia Station was a Babcock Hitachi plale-type calalyst.

This calalyst is a TiOl-based plate calalyst., developed and manufaclurcd by Hilachi- The pilch of

the catalysl was approximately 10 mm.

Thc coals produced ash lhat had significanl accUllllJ1alions of ash on the catalyst On both

macroscopic and microscopic levels. On a macroscopic level, there were significant observable

accumulations lhal plugged the enlrance as well as lhe exit ofthe calalyst sections. On a

microscopic level, the ash materials filled pore.~ in the eatalysl and, in many cases, complelely

masked the porcs within 4 monlhs ofoperalion.

The deposils on the surfaces and within the pores ofthc calalyst consisled ofmainly alkali

aml alkaline-earth clemcnt-rich phases lhal have been sulfaled. The resuHs of this testing found

lhat the <5-fIm ash rich in alkali and alkaline·earth elements is captured on the surface and

wilhin the calalyst porcs_ These materials react with SOllSO, in the flue gas, resulLing in the

formation ofa continuous phase lhat blinds lhe ealalyst. The ability of elemental mereuryto be

oxidized across the SCR calalysl was investigated al a North Dakota lignile-fired plant. Thesc

resulls showed nO oxidation of mercury across lhe SCR calalyst.

The reactor was inslalled at the Baldwio Stalion and operated for a 6-monlh lime period On

thc Haldor Topsoe catalyst. The information obtained from tesling included pressure drop,

_.• sootblowing cYcles, and reactor lemperatures_ Figure 10 show "the pressurc drop across the

calalysllest periods from 0 10 2 monlhs. During the lirsl two monlhs of operation, the pressure

<- was aboul 0.5 inches ofwater; at the end oflwo monlhs, lhc pressure <irop was about 0.8 inches

ofwaler, indicaling plugging had occurred_ The air was pulsed a minimum ofevery 8 hours in an

altempllo maiutain deanliness_ The reactor was monitored on a daily basis, and adjuslments in

pulsing cyclcs wer" made in order 10 minimize deposit accumulation. However, for the firsl two

months, the pressure drop slendily inereased. There are several periods where the uuil was laken

off-line; during lhose limes, the temperalure oflhe calalysl was maiutained. Al 2-monlh

inlervals, n section ofcalalysl was removed and replaced with a new one.

For Months 2 through 4, the pressure drop was hIghly variable inilJally bUl was aboul

0.8 inches ofwater. From Monlhs 4 through 6, the pressure drop was maintained belween

0_6 aud 0.8 inches ofwater. This is due to the installation of a fresh calalysl scelion and leaving

two thirds oftbe catalysts in place that were partially plugged. The gas veloeily in the single

section ofnew, clean calalysl was high because ofchanneling, and the resuH ofthe high gas flow

was less deposilion and accumulation. Gas vcloeily has a significanl impact on the polenlial for

deposits to form. However, at high gas velocity, low NO, conversion Is likely.

The reaclorwas inslalled allhe Columbia Station and operaled for a 6-month period of

lime wilh lhe Babcock Hilachi catalyst. The information oblained from the tesling included

pressure drop informalion, sootblowing cycles, and reactor lemperalure. Figure I1 shows the lesl

periods from 0 to 2 months. 1be pressure drop aeross the SCR upon installation was aboul

0.4 inches ofwalcr and increased 10 an average of about 0.5 inches of water, but ranged from

less than 0.4 to greater lhan 0.8 inches ofwater. The pressure drop for Months 2 to 4 increased

from about 0_5 to 0.7 inches ofwater because ofaceumulalion of ash. After cleaning the rcactor

and replacing one catalyst seclion, the pressure drop was aboul 0.3 but increased to over

"
0.6 inch,,-, "fwaler up 10 aboul4100 hours. There wa~ an outage a11he plant, and aggressive

pulsing oftile reactor W,LS conducled; lhe pressure drop was broughl hack down 10 0_3 but

rapidly increased 10 over 0.5 inches ofwater within 500 hours.

The ~ame reaclor lhal was inslalkll allhe Baldwin Station w,,-, moved and in~lalled al the

Coyole Sialion. In ,1{IJilion, the same H,lIdor Topsoe catalysllype wos used in lhe reoctor. The

reaelor was operated for a (i-monlh period oftime. I'igure 12 shows Ihe test periods from 0 10

2 monlhs. As Ihis paper is being prepared, Ihe reactor is slill operating on-site. The pressure drop

aLTOSS the calaly~t upon installation wa~ aboul 0.4 inches ofwaler. Afl"r only 750 hours, the

pressure drop wa_, 1_5 inche", "f waler, indicating significanl pliJgging ;lnd hlinding. Very

aggressive air pulsing was conducted, wilh lillle success in removing Ihe deposils. The pressure

drop for Ihe calalysl was over lwo limes grealer thanlhe pressure drop observed for the Baldwin

Station utilizing Ihe same reactor end same calalysl. Al aboul1700 hllllrs, the reaClOr w"-,

cleaned, and a seclion ofealalyst was removed lor characlcrizalion. The prcssure drop afler

clcaning was about 0.8 10 1.0 inches ofwatcr. TIle pres~ure drop did n01 incrcasc as rapidly

bccause of the higher velocities Ihrough lhc clean section oflhc calalyst_

The lOpS ofIhc catalysIs wcrc pho(ograph~dduring inspecliun and sampling oflhe catalysl

sections. Figure 13 shows Ihc ash materials thai accumul"led on lhe calaly~t inICI "n.", 2 monlhs

of operalion_ Thc mOSI significanl accllmulalion was nOled for the Coyole Slalion, followed by

Co lumhia aml Raillwiu. The Coyole Slali"" had some larger pieces of,,-,h deposil m~terial On lhe

surIace a~ well "-, plugging 0 f the ~atalysl passages. The Baldwin St~lioll showed some ohvious

deposilion along the walls of the reactor and some accumulalion on the inlel sections. The

Columbia Station showed more significanl accumulation and ~lngging limn Ihe Baldwin Slation.

Aftcr 4 months, Ihe lops ofthe calalysls were pholographcd durIng inspection and

sampling ofIhc catalyst scclions, as shown in Figure 14_ The mosl signi ficanl accumulation was

"oled for Ihe Coyole Station and somc accumulation for Ihe Baldwin Stalion_

sel{ Ash Deposit Ch3rade,·jzalion

The characleristics of the ash materi~Js thaI eollceled on Ihe calalysl surf..1ccs and pores

were characlerized by SEM and x-ray microanalysis and, in selecled cases, XRJ) was used 10

detcrmine Ihe cryslalline phases present. The catalysts were sampled afier 2, 4, and 6 monlhs_

·nlC scclions were sampled, and approximalely 2.5-cm squares wcre mounled for SEM analysis

on double-slick lapc and in cpoxy resin. The double-stick lape "ample~ allowed fur

charaClCril.aLIon oflhc exlernal morphology ofthe particles and calalysl surface. The samplcs

mounled in resin were cross-seclioned and polished, which allowed for more delailed and

ljuantilalivc analysis ofthc honding malerials and matelials Ihat accumulatell in Ihe porc>: {l[Ihe

calalysL Delailed information on allihe samples can be found clsewhere (add FPT reference).

Exmnples oflwo deposil and calalyst analysis are presenled here.

"l he 6-month sample from the Baldwin Slali"n 8howed eden.,iv" sui falion of Ihe alkalineearth elemenls presenl in the deposits. Figures 15a ~nd 15b show regions oflhe ealalysl where all

lhe pores were blocked and a minimal amount ofdeposit on Ihe surf..1ce oflhe cat~lysl. Figure
'-'

*-"

I w

i;l~

15c shows a higher-magnification view ofthe deposit that is tilling the catalyst pore. The deposit

con8isls ofpartie]es offty ash bonded together by a matrix ofcalcium- and sulfur-rich material,

likely in the form ofcalcium sulfate. The chemical compositions ofselected points (hat indicate

the presencc ofhigh levels ofeaIcium and sulfilr arc listed in Table 3_ There is much more

extensive bonding ofthe materials wilh the sulfate matrix as compared to the 2-month somple. In

addition, there are some regions ofhigh levels ofcalcium, aluminum, and sulfur present. -nle

calcium aluminum materials arc likely derived from the calcium aluminum phosphate minerals

found in the coal fired at this plant.

The 4-month samplc from the Coyote Station showed particles adhering to the surface and

filling pores in the catalyst. Figure 16 shows the 4-month sample from the Coyole Station. The

catalyst showed particles adhering to the surfl\ce and completely filling and masking the pores in

the eatalysL The external morphology ofthe catalyst surface shows the masking ofthe catalyst

surf..1ce. Chemical compositions ofselected points arc shown in Table 4_ The 4-month sample

shows more sulfalion than the two months of exPOSUfc samples. Figures 16b and 16e shows a

bighcr-magnilication view ofihe dcpositthat is lilling the catalyst pore. The deposit consis!... of

particles ofily ash bonded together hy a matrix ofsodium-, ealcium-, and sulfur-rich material,

likely In the fonn ofcalcium sulfate. Significant soo:lium was found in the deposits, as shown in

Table 4_ The sample shows signilicant evidence ofsulfation after months of exposure and was

much more pronounced lhan lhe samples for the Baldwin and Columbia Stalions that are fired on

"""PRB coals. The preseuce ofsodium enhances the bonding and sulfation ofthe particles to foml a

-"strongly hondcd matrix (22).

SCR Deposit Formation Mechanisms

TIle mechani~TIl for the fOffilation ofdcposits that blind SCR catalysts involves the

transport ofvery small particles rich in alkali and alkaline-earth e1emenls, the surface oflhe

catalyst, and reaclions with SO,/SO) to Conn sulfatcs_ The fonnation ofSO) from SOz is

catalyzed by the SCR; this, in tum, increases the reaction ratc ofSOJ to form sulfates_ In some

cases, the alkali and alkaline-earth elemems will also react with CO, to form carbonates. XRD

analysis Identified CaS04 as a major phase and CaJMg(SiO.), and CaCOJ as minor phases.

Lignile and subbituminous coals eonlain high levels oforganically associated alkali and

alkaline-earth elements including sodium, magnesium, calcium, and potassium, in addition to

mincrnl phases. The primary minerals present in these coals include quartz, clay minerals,

carbonates, sulfates, sullides, and phosphorus-contaIning minerals (6)_

During combustion, the inorganic components in lhe coal are partitioned into various sIzc

fractions based on the type ofinorganic component, their association in the coal, and combustion

system design and oper~ting condilions. Significant research has been conducted On ash

fonnation mechanisms and rclnlionships to impacts on power plant performance (1---6, 9-13, ]9-

21, 29). During combustion, [he inorganic componenLs associated with western subbitumillous

and liguile coal typically are distribllted into various size fractions of ash. Thc smaller size

fractions of ash are dominated by partially sulfated alkali and alkaline-earth elements_ These ash

particles are largely derived from the organically associated cations in the coal. The larger size
fi-dClioo has higher luvels of aluminum nnd silicon derived from lhe mineral fraction ofthe ashforming component ofthe coaL Enlrdined ash was cXlracted from the Cohlmbia Slalion at the

point ofthe inlet to the SCR reactor and was aerodynamically cla<;sificd and ollalyzed. Thc

composition ofthe size frncliollS wns compored 10 lhe chemicol composilion ofthc ash dg]()siled

on and in the calalysl, as shown in Figure 17_ TI1C comparison shows thol Ihe comp08itioll ofthc

particle c,1plured ill the SCR calelysl is very 8imilar 10 the <5-flm sizc fraclion, The dcposited

matcrial shows significnntly more sulfalion then the entrained-esh siz~ fraclion, indicaling Ihnl

thc sullation process occurs after the particlcs are deposited ill lhe catalyst.

The mechanism of SCR calalysl blinding when firing lignite Or subbimmillolls coals is

shown ill Figure 18 (JO). The requirements for lhe fomlalion of deposils thai blind SCR calalysl

include filing a cmd Ihal produces si gnifieanl levels of <5-fllll-5i~ed particles. The parlicle." ore

lransported inlo Ihe pore:; oflhe ealalysl and subse(]uently reael wilh SO, 10 form suI fal,,""_ The

sullilte [orms a mntrix thnt bonds olher nsh pnnicles. The SCR ealaly/.es the fOlmation ofSOJ

and lhereby increases lhe rate ofsulfation (24, 25). 'nlC sullution ofeaO increases lhe molar

volume, resulling in lhe filling oflhe pore. For eoals thai have high sodium conlents, fOlTIlalion

oflow-melling-poinl phases sueh ns pyrosuUates is possible (3 I). Pyrosulfole malerials can mell

at lemperalures as low as 535"1' in eoal-fircd power syslems.

0.025

0.030 Fe""

Welghl "" Gain lor LSUS-PR8 Blend

/I;lOOOF

I

r 700'F

__-600°F

/ ~.

.- -_._-_. -

,

o

o

0.020

0.010

0.015

0.005

c

••

"

Time, min

Figure 8. Wcighl changc~ for PRB-blend coal ,,-,h exposed to flue gases and ammonia al lhree

lemperatures.
, ~-- Baseline and Catalyst Tests for PRB

,

/ PRB + Calalysl

, ! P~ Baseline

, ,

I

,

,

I

,

, /

1/

0

0_00

0.00

L

0> 0.00

E

-0> 0.00

E

c 0.00

•

co

1: 0.00

9'

- 0.00 ..

"

Time, min

"0 ''''

Fignre 9. Weight changes for PRB-blend coal ash exposed 10 nne gases and ammonia wilh and

withonl SCR calalyst present.

,];

'-~" "

"

L'

a

" I

c

"

U

" 0.'

i 0.'

0

0.-

0.2

0.0

0 200 600 800 1000

Run Time, hr

"00

Figure 10. Catalysl pressure drop al Baldwin Stalion al 0 10 2 months ofopcration.
'2T-------------------------'"~~"~~~"-'\

wt------c----;------------1

o~I 0.6-1-----

c

-0 0.6,'----cf-

<

0.4

o

0.'-1-----'----'----"---------++---1

moo 1500

oo+------~------~----"'''----j

o

Run Time, hr

Figure 11. CalalyGl pre."urc ~n)p at COILl",hi" SlattM at () 10 2 month' of 01'C"U;Ofi.

'.0

L"

L'

0

- H I

c

"

U , .0

ti

0."

0.' U

0'

0.'

00

0 1000

Run Time, hr

Fig"re 12. Calalyst pressu'. drop at COyulc SlallOn "I 0 [0 2 munlh, ,,! opomlion.
~-,

"

g "" ".

.,

Baldwin Slation arler2 months

COylJte Slation llfler2 months

ClJluwbia StatilJn 311er 2 months

Figure 13. Piclures of catalyst inlet after about 2 months oftesting at each plant.
o

,

,

:

\ '. , ._, 0

F'RG "",,,",,,,eM

_A> ';',

'~&; ",,-,"

,.,' .c;-

:7 \.

,

,

, , ,

Baldwin Station arlcr 4 months

Coyote Slatilln after 4 month.

Figure 14. Piclure, 01" ".loly" inlet aflcr alm"1 4 month, of cxpo,ure [" llue MOl "nd p"nirulalC.
A

B

c

Figure 15. SEM images of asn collecled 011 calalyst surface at !he Baldwin Station after

6 momhs of exposure. A) ,md 11) low-magnification images ofash deposit on calalyst surface
and C) high-ma!1'ifiealion image ofpolished eross section showing pmliclcs ill a malrix of

calcium- and sulfur-rich lTIolerials.

T.I>I~ __~.!'.~nlj<"1 Composition of S<ledt~ Points "nd.;\.~o"s.i." F:igll.c" 15 - ..----

Chomical cumpu,ili[]n (um1l1llIize-tJ wl% eqllivolent oxide) _._---

Oxide Poinl , Point 1 I'oim J Poin!4 P"in[ 5 Point fi

1.1.1

M '0

" o, 0.5 n

Na,o 4.3 2.5 0.3 e, Ui 7_6

MgO 14.8 10.0 15.0 155 14.7 e.o

Al,O, ),3 U 18.8 'i7.7 n 47.3

SiD, n 2.1 e, '.0 '0 ,.,

P20 , 30.7 20,4 17.7 "." 2~.O

SO,

'"

K,O 28,8

"' 2~.7 "28.1" 22.5"' 34.~ " 2~,4 "

C,O '" " " CO L3

TiO, 11.4 ]2,9

"

"' o.e H 7.~

Fe,O, " " " ,e o.e

0,0

" ._- . Tolal W" W" W" '00 W" '00

Oxide Poin< 7 P"iu[ PlIim9 l'oin!IO Point II Poinl 12 _..._.- ._-_.

1.1.2

u "' 05 " U

Na,O "

" 0' ,., '" H 0.'

MgO ,. " 3.0 19.2 10.8

Alp, 0' I8.4 18.5 JI.O 17.4 10.7

"

SiO, U 0.'

'" ".e u ,-'

1',01 37,9 U 5,3 ".e n.s 13.9

SO! e, ,." "" "., '.K "-"

K,O 31.4 52.6 49.0 28.9 30.0 45.4

CaO

"

.,

TiO,

" " " "

" " 0.' 0.' o. , 0.'

h,O, "" '.0 n ,1.2 2.Y

BaO

"

Totfll W" WO WO 000 W" W"
A

B

c

Figure 16. SEM images of ash collected on calalysl surface allhc Coyole Slaiion aller 4 months

of exposure. A) low-magnification image or ash deposil on catalyst surface, B) low-
nwgllifiealion image of polished cross section showing p;n1ic1es in a matrix ofcaJciulll- and

sulJiJr-rich malerials, and C) highcr-nmgniJication image of bonding.

1.1.2.1 TaJJ.le 4. Chemical COlllposition of SclccLcd Poi"ls nnd Areas in Figure 16

Chernic,l ~"IIlJl,,,ilion (uormali,od wl% "'luiv,lenl oxide)

Oxide ---",""""",==="C"Cm"C,~ Poilll3 Point4 PoilUS

1.1.3

6.7

" " 6.2 3.1

N"O

" "

U

M,O 2.6 U

" "

" U 10.5

AI,O, '0 21.1 113 5.6 32.2

SiO, 02

" " OJ O.~

P,O, 54_7 38.5 56.4 57.5 30A

W, '" '" 0'

K,O IRO 3.4 15.8

'"9.3

"

D

CoO "' " "

u

" TiO, H

Fop, ,., 13.'

" "00" "

'" ,.. 0,0

----- -----------

Tolal '00 '00 000 '"0 WO

O.ide Poim6 Poln! 7 Poinl S Poinl9 Poinl 10

1.1.4

0.' ,.• 10.4

No,O U

'" '"

'" U ).0 U

M,O ,.• " "' '" 10.6

Al,O; 6.3 18.2 10.5 '" 28.9

SiO, "' , .0 "" O. ,

"'

P,O, I.B 28.4 ~~.9 «., 23.4

SU, " 4.3 .., '" H

K,O 24.5 '0 22.5 lH

C,O 0.' 0.' U

" "

u

nO:, " •• LO " 13.2

!'e2O, " 22.) 0' '" 6.3 0,0

-- Tolal 000 00' .00
=~f~~~~l===========~~:IT:~:":IT'-:~~ ,,- 121 <lJ1rn

E8 1 104.6 J1m

4.610 22J1m L _

1i!llI>22/lm I

EE Catalyst Ash

E "

•

rn " .~

0

Jr 20

,.

*

rn

"

• W

"

,

0

'"

i 0

,'"

Figure 17. Comporis"" ofonlrairu,ci ash and "<posited ash on calalys( for Columbia Sialion.
Pore

Sulfur Oxides

Carbon Dioxide

No Dcteriomlion Yet

(NHJ and NO, can react in

micropore on catalyst surface)

- Reactions with SO,

and CO2

14% Expansion

/~--M"'ri'Mo''''''''' _ ,,"IIy Sulfa'.d AJk.dh on~ Mkal;oe·EMh 0"-'""

'- P"",das _ 5,I,co'0, 000 OLher Fly II.Sh p"",",,,,

Deterioration

(NHJ and NO. cannot react in

micropore on catalyst surface)

Figure 18. Mechanism orSeR cntnlysl hlinding via the fOffilolion ofsulfates and carbonates

(IlIodiIicd after Pritchard and othcrs r30])_

Low-Tcmpcraturc Pyrosulfates

Thc presence ofsodium sulfale in Ihe nuc gas exiling a scrubber will call'" problems 10

low-dust and lail-m<l devi~e" such as selective calalytic redudion (SCR) syslems for NO,

redUClion. There are two problems associntcd with the line parliwlale rich in 80dium sulfntc on

downsLJeam devices. These include accnmulation of fine particle, on lhe SCR lhat, when

sOOlblown, will cause opacity problems, and lhal the fine particles on the SCR will fonn

pyrosulfales such as (K,.~a O.j )S,~ thal have mehing poinls as low as 535"F (31) lhat will

blind lhe catalyst The pr~,~nce "fthese eom[>ounds in low-lemperalure CO[fo,ion deposits is

well known (32). In addililln, Ihe presence orso, enhances lhe lormnlion ofthe low-meltingpoint pyrosulfmes (31)_ The sodium sulfale mamrials will cause opacilY nnd SCR calalysl
;;;"

lli

~~

blinding problems lhallimillhe feasibilily ofthe 10w-t1usl or lail-end SCR lcchnology for usc

with high-sodium lignite eoals_

The sodium sulfalc materials will be 1r;msported 10 lhe ealalyst surfaces by diffusion,

dcclrophoresi8, and, possibly, inertial impaclion. The particles ~re hcld in place by we.1k

eleclroslalic and van der Wa~ls forces_ Once accumulalion lakes place, lhe sodium sulfale

particles will react wilh Duc gas components, resultIng in lhe formation ofpyrosulfales. The

fOmJaLion ofpyrosulfates involves the followingprocesscs (31):

1. Formalion ofsulf"le.<; such as NaZS04 and K,SO.

2. Conversion of SO, 10 S03 in lhe bulk gas phase - catalytically adive surface such as an

SCR calaly:;l - SO, + Y, O2 ---Jo SOl

3. Pyrosulfale formalion - Na2S0. + SOl ---Jo Na2S~Q.

The melting poinls ofseJecled pyrosulfate phases are shown in Table 5_

Table S. Mellin!! Points or Selected Pvrosnlfale Compounds

CompulInd Temperature, "C Temperature, OF - .. - ----- Kj Fe(S04), 618 1I44

Kj AI(S04)1 654 1209

KFe(S04)2 694 1281

Nn]Fe{SO')J 624 1155

NnlAI(S04)J 646 1195

NaFe(S04)2 690 1274

Na~S~Q. 401 754

KlS:!Q. 300 572

(K15N~.,)S,Ol 279 535

Melling poinls forpyrosulfates belween 5350 and 770"F havc been reported in the

lileralUre. Much Oflhe past work has focused on lhe formalion oflhesc phascs on tube surfaces.

These species contribule to lhc corrosion ofheal-traIlSfer surfaces in coal-fired power plants. The

exact rnelling point depends On lhe reinlive amounls ofsodium and/or potassium. ,

There is significant evidence for lhe formation ofsodium·rich fine particulale in full-scale

power plants when firing high"sodium-containing coals. For example, Minnesota Power's

Boswell Energy Slalion found that w]lcn il fired high-sodium, lower-"8h 8ubbituminous coal, it

experienced increases in opacily. Hurley and Kalrinak (33) condueled a field-testing project on

Unit No_ 4, a pulverized coal-fired boiler equipped wilh au clectrostatic prccipilalor and a wei

scrubber, 10 beller understand lhe reasons for the opacIly problems. During lhe field lesling,

sampling oflhe coals, nue gases, and scrubber materials was eonducted_ The particulale in nile

gases downslream orlhe scrubber was aerodynamically classified using an impactor and
mllllieyc1one. The si~.ed Ii-action., were analyted 10 delermine Ihe composition oflhe subminonsized fraction.

The T1,"uIL, o[the .'lully indicaled Ihat the partieulale collected downslream of the ",cmbber

was cO;1J-relaled ami caused by thc high sodium contenl "I' onC of the coals. Vapor-phase sodium

condenses in the conveclive pass 10 form line sodium sulfate ]Jartic1e~ or olher Na species Ihal

Inter react with nsh pnrtic1cs. Pure Na,S04 p~rtides are 100 sm~llto be removed by seruhhing.

CONCl..LJSJON, sen IS NOT FEASIBI.E FOR NO); TtEDUCTION AT MII:rON R.

YOUNG

The ilsh dep08itioll behovior ofthe lignites from North Dakota is the illo,t cnmplex and

severe OfollY coals in the world, md inslallalion n[catalysts for NO, redllcti'!n is going 10 be

impossible because ofthe fOlmatioll ofsodium calcium suI fales in thc pores u[the calnlysL

Following is a list ofthe key roodbloeks associated with lignites which have not been OVercome

and, in our opinion, makc Ihe inslnllalion 0 f SCR c;ilalysl ill the lVlRY plant lechnically infeasihle

for NO, control.

• High olkali ond alkaline-earth clemenlS pres~nt in the coal fired althe MRY plant form

sulfalc.s Ihat blind Ihe catalyst.

Cyclon~-firing partitions thc ash during combustion. As n rcsult lhe level of

sodium and calcium in Ihe fly ash is enhanccd and win i"crcase the SCR

catalyst hlinding_

Sllifale reaclions increase with incre~sing temperalLLre, and th" wggc--Sted

temperalure ofinslnlIalion at the MRY facility is higher than typical

installations; lllCfcfore, sulfation problems are enhanced.

Sulfole formalion is also enhanced by Ihe presence ,,[an SCR calnlyst; this

accelcr~les Ihe suJralion reactions, causing blinding 0 f the calalyst.

The high levcls ofsodium in the cOols combined with calcillm prodllce., low"

ruching-poinl euteclic compounds Ihnl will mell on Ihe sllrf..1ce.

Sullalcs form on the surfac~s ofcolnlysls firing PRB COols. Lignites wjll bc

several ordcr:; of magnillldc worse becnusc of the higher Icvels ofsodium.

• The ash components 10 impacl SCR perfomlanC~in Japan and Europe (14- 16) includ~

alkal i and alkaline-e~rth clemcnls lhat resull in sulfale forolation_ The lol~l caleilllTI

content and the sum ofthe calcium, magnesillm, potassium, ond sodium provi(le an

indicalion Oflhc problems that OCCUf_ For the coals lircd al [he MRY pow~r plant, Ihe

CaO content ranges from 6.80/0-] 9_99%, and the Sum oflhe alkali and albline-earlh

elernent~ range from 9.330/0-29.87% ofthe a~h_ The levels ofcalcinm in Center lignite

are 2 10 4 limes higher than Ihe problematic coals in Jilpan and Ellrope.

• TIle finding or work conducled in GemJany and Jnp~n were confirmed by recent SCR

catalysl slipSlream tesling Ihnt showed significant cvidence ofsodium and calcium-
rich sulfate fonnation that fill and plug the catalyst at both lignite (North Dakota)- and

subbituminous-coal-fired power plants_ The results orthis recent testing showed that

the presence ofsodium significantly enhanced the fonnation ofbonding ofparticles

and more rapid sull:'llion, filling ofpores, and rapid increase in pressure drop aCross the

catalysL

• Deposit cl\fl)'Ov",-, urpopcorn ash, plugging the top of the SCR catalysl with deposit

fragments, is a significant prohlem because orthe extremely high deposition potential

orthe coaL The formation of deposits in various parts orthe boiler requires continuous

sootblowing_ The deposit fragnlenls are likely going to be camet! with the bulk gas flow

to the SCR catalyst, rcsuhillg in plugging.

The variability oflhe lignite is a problem ofunique concern at MRY. The deposition

potential ofthe coal is always changIng mpidly, resulting in rupid growth and formation

ofdeposits in various sections ofthe boilcr. Aggressive sootblowing of all fireside

surfaees is aJreiuly required Lo maintaIn full-load operation. The sootblowing of

upstream heat exchange equipment will cause deposit fragments to be carried back to

the SCR catalyst, and during sootblowing ofthe SCR catalyst, tbc entrainment of

deposit frngments 1Iiong with the sootblowing media will result in significant erosion of

the catalysL surfaces.

The ash-related impacts ofthe ligniles from NOrth Dakota are the most complex and severe

of any coals in the world, and inslallation oftail-end SCR systems for NO, reduction will not be

possible. The key problems nssociated with lignites Lhat bave not been overcome nnd, in our

opinion, make Lbe instalbtion oftail-end SCR systems at the MRY plant technically infeasible

for NO, control at MRY's Units I and 2 nre listed below:

X High-sodium lignite coal from the Center Mine Hngel A and B seam coal produces

extreme levcls ofhomogeneously condensed sodium sulfate ton! pass through the wet

scrubber. Tn nddition, the cyclone-firing system captures much orthe nsh as slag,

resulting in a decrease In ash that is available for providing condensation SileS for vaporphase sodium compounds upon gas cooling. This resulls in an increased homogeneous

condensation ofsodium sulfate.

X These small particles pass through a wet scrubb",- and will accumulnle on surfaces of tail_

end SCR syslems. The accumulated materials cannot feasibly be resolved through

conventionnl sootblowing and cleaning technologies to remove the prutieulnte.

X Recent testing Wi~l subbjtnminous nnd lignitie coals iudicllted a signifiennUy higher level

ofpore filIil1g and plugging in lhe entalyst exposed to ligniLe ash as compare to

subbituminous coal ash. The catalyst pores as wel] as lhe catalyst surface in the lignite

tests were completcly coated with a sodium calcium sulfate material, while only pore

filling was found in the subbituminous coal testing. The pressure drop aCross lhc catnlyst

exhibited for lignite was 4 to 5 times greater than that found for a entalysl exposed to

subbituminous coal ash. The plugging occurred ov",- a 1000 hour test period.
The fOimalion ofli(jllid pyroSlllf~le m~lerials ;lllemperal"re.< as low as 535"1' Ii-om sodium

sulfate materials oecurs in eoal-fired power syslems and is well documenleiL Pyroslilfalcs will

lorm and eausc blinding oflail-cnd SCR dcvices.ln addition, SCR sysLems caL~ly,oe Lhe

fonrmLi"n ofSOJ fwm S02. The pIT~cncG ofSOJ sigoificanlly enhances lhe Iomlalion oIlhe

pyrosulIales al MRY to an extreme 1cvellh"1 cannot be deaH with effeclively u'ing cleaning

lcehnologies thai cxislto<.1ay.

REFERENCES

I. Mehla, II.; Benson, S., Eds. EJJecls oj Coul Quality Oil Power Plu,,/ M"",rgcmelll: A.,h

ProMe",,,, Jl1a"agemeJlI. "lUI Solu/io/J.I'; lJniltd Engineer;ng FOllndalions Int.: Ntw York and

ErRl: Palo Allo, CII: 2001.

2. Schoberl, RR i.ignites ofNorth Amerira; Coaf Sciencr and Techllology 21.' El~evier:

New York, 1995.

J, Baxter, 1..; DeSolJar, R., ros. App!icafiol/s ofAdva"ced Technology to Ash-Refuted Prohlem.<

in Boikrs; Plenum Press: New York, 1996.

4. Couch, G. U"dcrs/III1Ji"f{ Slogging amf Fuuli"g During pICvmbusrion; lEA Coal Re'earch

Report; 1994.

5. William.lon, J.; Wigley, E, Eds. The Impact ofAs!llJeposition all Coal Fired Plants.-

Proceeding., aftlle F:lJgil1eering Faulldotion Conference; Taylor & Francis: Lon<.1on, 1994.

6. Ben8on, S.A.; Jone8, M.L; Harb, J.N. Ash l'ormarion and Dcposilion-Cb"pleT 4. In

Frmdamemals ofCoal Combuslionfor Clean and EjjicieIJ/ Use; Smoot, L.V., Ed.; El~evier:

Amslerdam. Londoll, New York, Tokyo, 1993; pp 299-373.

7. Bcnson, S.A-, Ed .I/lorganic Tra,,40rmal;'J/is and A.<h Depositiu" During Comlmslion.

Americon Society oJ _1I,.1cehanieal Enginecrs lor lhe Ellgineering Foulldmion: New York,

1992.

R. Bryers, R.W.; Vorrcs, K.S., Ed". ProceedilJgs ofthe Engincerillg Fowulatifm Cmifcrellce A"

Mineral Matter u"d Ash {)epositioJl frail! Coal, Santa Barbara, CA, Feb 22-26, 19S9; Uniled

Engineering Tmslees lne., 19~O.

9. Raask, E. Erosion Wear in Coof Wilily Boilers; Hemisphcre: Wnshington, 1985.

1o. R~a,k, E. Mineral Impurities ill enal CombustIon; Hemisphere: Washington, 1985.

11. Benson, S.A., Ed., Ash Chemistry: Phase l/e!ariollShips in Ashes and Slags, Speeiallssue of

Frle! Process. Techl/ol.; Elsevier Scicnee Publishers: IImslerdnm, 1998; Vol. 56, N,,". 1-2,

168 p.

..,
,

"

12. Laumb, M.; Benson, S.A.; Laumb, J. Ash Behavior in Utility Boilers: A Decade of Fucl and

Depo5il Analyses. Presented at the Uniteu fuginccring Foundation Conference on Ash

Deposition and Power Prolluclion in the 21st Cenlury, Snowbird, UT, Oct 28 - Nov 2, 2001.

13. Benson, S_A_; Hurley, J_P.; Zygarlicke, CJ_; Sleadmall, E.N.; Erickson, T.A- Predicting Ash

Behavior in UtilIly Boilers_ Energy Fuels 1993, 7 (6),746-754.

14. Licala, A.; Hartenstein, H-U.; GUlberlet, H. Utility Experience with SCR in Germany_ 16th

Anlluallnlcmalional PillShurgh Coal Conference, Pittsburgh, PA. Ocl 11-15, 1999.

15. Cichanovicz, J.E.; Bruske, D.R. An Assessment or-European Experience with Selective

Catalytic Reduclion in Genuony and DCJUnark. EPRJ-DOE--EPA Combined Utilily Air

Pollution Conlrol Symposium: The MEGA Symposium, Allanta, Georgia, Aug 16-20, 1999.

16. Cichanovicz, J.E.; Mnzio, LJ. Twenly-Fivc Years ofSCR Evolution: Implications for US

Applications and Operation. EPRT-DOE-·EPA Combined Utility Air Pollution Control

Symposium: The MEGA Symposium, AWMA, Chicago, IL, Aug 20-23, 2001.

17. Benson, S.A.; Kong, L; Katrinak, K-; Schumacher, K. Coal Qualiry Management Sy.<tem;

Final Report for North Dakota Industrial Commission; Sepl 1997.

18. Kalrinak, K.; Benson, S.A; Lmunb, J.; Schwalbe, R; Peterson, W. Matching Lignite

Characteristics alld Boiler Operation; Final Report for North Dakota Industrial Commission;

Aug 2000.

19. Sarofim, AT; Howard, JJl; Padia, A.S. TIle Physical Translormations ofMineral MaHer in

Pulverized Coal Under Simulated CombustIon Condilions. Cambl/st. Sci. Tech"o!. 1977, 16,

187.

20. Loehden, D.; Walsh, P.M.; Sayre, AN.; Beer, I.M.; Sarofim, A.F. Generation and Deposilion

ofFly Ash in the Combustion ofPulverized Coal..J. l"s/. Energy 1989, 119-127.

21. Zygarlicke, C.J.; Toman, D.L; Benson, S.A. Trends in the Evolution of Fly Ash Size During

CombUSlion Prepr. Pap.-Am. Chern. Soc., Div. Fuel Chem. 1990,35 (3), 621-636.

22. Benson, S.A.; Fegley, M.M.; Hurley, J.P.; lones, M.L.; Kalmanovitch, D.P.; Miller, B.G.;

Miller, S.F.; Steadman, E.N.; Schobert, H.H.; Weber, 8.J.; Weinmann, l.R.; Zobeek, BJ.

Project Sodium: A DetailedEvaluation a/Sodium Effects in Low Rank Coal Combustion

Syslems; Final Technical Repnrt; EERC publicalion, July 1988.

23. Hurley, J.P.; Erickson, T.A.; Benson, S.A.; Brobjorg, J.N.; Steadman, E.N.; Mehta, A.K.;

Schmid~ C.R Ash Deposition allow Temperntures in Boilers Firing Western U.S. Coals.

lnlemntional Joint Power Generation Conference; Elsevier Science, 1991; pp 1-8.
24. Laurnh, J.D.; Benson, S.A- Dench- and Pilol-Scale Sludic.> o[SCR Calalysl Blinding. In

Proce('aing firPowcr Production;1l [he 21s1 Century: Impocts firFuel QualifY ond

Oper(l/;ons; United Engineering Foundalion: Snowhird, UT, Oct 2001.

25. Crocker, c.R.; Benson, S.A.; Lmuub, J.D. SCR Catalyst Blinding Due 10 Sodium and

Calciulll Sul[ale Formalion, Prepr. Pap.-Am. Chern. Soc., Div. Fud Cbem. 200449 (I), IG'l.

26. Benson, S.A.; I.aumh, J.D.; Crocker, C.R, BJimling o[thc SCR Calidy:;ls ill Ligui le and

SubbiluminOIlS COid-Fired Powcr Planls, Prcseoted ai The Clcnrwnter ConferCllcc On Coal

Ulilization & Fuel Systems, Clcnrwaler, FL, April 1R-22, 2004.

27. Senior, c.L.; Linjcwilc, T.; Dcni~on, M.; Swensen, D.; Shino, D.; Boekdie, M.; Baxler, L;

BartholollCW, C; Hecker, W.; Guo, X.; Nackos, A.; Whilly, K.; Eddings, E. SCR

Deaelivalion Mechanisms Relaled [0 Alkali and Alkalinc Earth Elemenls, 200] Conference

on Se1eetive Catalytic Reduclion (SC1t) alld Selectiye Non-CalHlylic RedUClion (SNCR) ror

NO, Conlrol, Pillshurgh, PA, Oct 29-30, 2003.

2g. Righy, K.; John.<on, R.; Neufort. K; Gunlher, P.; Hums, n.; Klalt, A; SigJing. R. SCR

Calaly~l Design TS8UCS and Operating .Experiencc: Coals with .High Arscnic Conccntralions

and Cmds from the Powder Riycr Basin, Presenlcd allhe lnlcrnalional Joinl Power

Gener"tion Conference, IJPGC2000-15067, July 23-26, 2000.

29. ASTM Mcthod D6784-02, "Standard Te'l Method [or Elemenlal, Oxidized, ParticJe-J3ound

and Tolal Mercury ill Flue Gas Generaled fmm CoakFired Slationary Sources (Ontario

Hydro Mclhod)," at hllp:l!www.a'trn.orglcgi-hin/SoflCan.exeJDATA13AS.E.CART!PAGESI

D6784.111In?E+rnysto,~.

30. Prilchard, S.; Hellard, D.; Cochran, J. CAlalyst Design Expcriencc for 640 MW Cyclone

Eoi IeI' Fired with 100% PRE Fuel, !lJill:!!Vvw~_.corlllcleeh.comll.9~l1ql!lali114e)i.hlfllL

]]. Singer, J.P. Combuslioll, Fossil Power Syxlems, Comhustion Enginccring Inc.: Winds"r, CT,

1981.

32. Chemislly a/Coal Utiliza/;on, S~eond Supplementary Volume. Elliot, M.A, Ed.; Wiley

Inlerscicncc; Ncw York, 1981.

33. Hurley, J.P.; Kalrinak, K.A. Delerminalion ofAsh Formalion and Deposilion Mechanisms al

Minne~ota Power Clay Boswell Slation; DOEIMC/I0637-]365, July 1992.
,

APPENDIX C

COST METHODOLOGY

CAPITAL COST ESTIMATE DETAILS 1,'ORNOx CONTROLS

O&J\:f COST ESTIMATE DETAILS liOR NOxCONTROLS

APPENDIXCI

COSI Melhodology

C.1 METHODOLOGY FOR ESTIMATED COSTS

NOx BACT Anlllysis Study

The summary economic evalu"tions ofeach aHernative arC prcsenled in lb.e cost imp~ct sections of the

ill"in report. Capital and O&M cost estimate., for each "licmalive are presentc""l individually. The

Levelized TOlal Annual Cost (LTAC) for "lIlhe alLertUltives for control ofa single pollutant (i.e. NOx)

frurn single unit is then prc>CTlted Logether with Unit O:mlrol Costs- The Lcveli7-"d ToLaI Annual Cost

(Ll'AC) reprcsents the levelized annual cost ofprocurement, construction and operation over a 20 year

dcsign life, again in current (2006) dollars. As a minimum, the d.,,;ign life for uny alternative waS taken to

be tha( reoommended by ~Thc EPA Air Pollution Contrul COSl Manual", Sixth Edilion, January 2002,

EPA1452/B--02-00 Ii.

The LTAC is also used to ealculale \he aV"'""b'C ~nnoal and increment"l cost crfectiveness of "<leb

allernative. T11e LTAC represent:; an annual payment in current day dollars sufficient to finance lb.e

project over its entire life.

In dctcrmining the LTAC u Capital Recovery Factor and an O&M Leveliz"tion Factorwere calculated

from (he project economic condilions and then applied S""P"TIllely [() the estimated capital and O&M costs.

The c(!uation used is shown below.

LACCfNPV=( ;(1+;)" ]=CRF

(1+0" 1

Where,

LACC = Leveli2ed Annual Capi"'] CO't

NPV = Net Prcsenl Value or ille capital invcstmcnlS required.

i di,count rate

n = design life in Y(:;lrs

CIU' = C~pital Recovery Factor

Therefore:

LACC CRF x NPV

For the economic conditions deocribed in Table C.1_lthe Capital Recovery Faolor was calculat~"(] to be

0.08718.

In dClermining the leveliz~"(] annual O&M cost the estimatcd annual O&M cost, the inflalion rate, the

discount ",Ie, and the equipmc"Tl1 life are taken into account. The O&M Lcvelizalion F"ctor (OMLf) was

cakulated as follows.

MillnkOl. Power Coopcr.uve, hlC. Cl·t Dum' & McDunnclJ
NOx BACT Anoly,i< Study

rAOMCI J1 = [I +i

J -1][ iJ (I ~O' ] = OMLF , l+i, (I+i_)'-I

Whore,

A = I .~vdizc,1 Annml O&ro.l Cost (LAOMC)

A, 'rolal amlUol O&M eOSI in currcnl dollar"

id ,hseolllli rale

i; = in tlotion ralc

n - design Ji re ill year,

Therefore,

I.AOMC-OMLFxA,

APPENDlXCl

Cu.,l MOltodology

for Ih~ {oconornic collditlllns dcsorib~u in Table C.I- I Ihe Opcf1lling and Maintenance l.e~d;zalion FaClor

W,," calculaled 10 he 1.24873.

The Levdizou Totol Annual Co"l, Or LTAC is Ihe sum of lhe leveli7ed "",pilal cosl and Ihe levelizc-d

Q&M oosl. Therefore:

I.TAC LACC + LAOMC = (CRF x P) + (OMLF x A,) = 0.08718 x P + 1.24M7J X A,

The uiffercnces betweel\ ahem"li,'e, "re also pre, en led lI,"phio"lly in Ihe fOl'm of u piN of Ihe annual

emission, reduolion (tpy) versus Ihe LTAC for ~.ch "Ilom"live. This I"nrrn ofplOI gr"phicolly depicls lhc

co,t eJYeclivelle.,S (I[ lIml Conhol COSL (io S/lrm ofpolllliant rednclion) of c"oh "Ilelllalive relative LO "II

of ll,e ,'lhers. The COSI effcclivene"' is abo refcrred to as the Unit Conlrol Cost and defJned"" lhe LTAC

ulvidcd oy Ihe annual emi.<sion, n:dllelion (Ion/yl')_ TI,e are" on Ihe plolllldicaled by Lhc various data

poinls represent, lhe cost eff~ct,vcncss envelope fm- the altL'TTmlive" undeL' consideralion. A "mOO~l Ii"c

is d,,,wn on Ihi.' plOl Gunnceling Ihe righlmOSI ruinls (thusc w'lh Ihe loweot eOSI fur a given level of

emissions reuuclion). Thi, li"e i:; rcfc"[nxllo as the Dominanl Conlrul Curve (DeC). TkDec define,

Ihe righl hand oOlUldary of Lhe envdopc cncompassillg all of1he allemahves cOl\"idered. The DCC i"

used as a .,e, eening 1001 belwcen con"ide",,j allcTImlives. Those alternativcs whose plotted posilion is

ahuve and/or 10 (he left oflhe DCC "rc nOl as CO"1 ctleclive;," lho,e [OImlllg the line and Ihus can he

eliminalcd from further analysi, ifdesired.

In order 10 comp"rc various pollu,"nl conlrol altemative.'<, ll,c Vnil Control COSL and lhc incremenl"ll Inil

Control COSI of each "Hernaliw we'ro "Iso caJculaLed and I~bllialed [01' comparison pllrpoSe"_ Tile Unit

Bum, & McDonnell CI_2 MiTlJ1kola Power Cn0l'eralJ>", Inc.
APPENDIXCI

Cap;,.l Cost Estim'les

NO~ BACT Analy.'is Sludy

Control Cosl compares conlrol lcchnologies on a basis ofdollars expended Il'" ton ofJXlllutanl reduced

($/ton)_ This relalionship is grnphicaUy clcpictcd in lhe DCC chart.

To mOre aecuralely compare belween ahernal;vcs wllh differenl cosls and control effieiencies, lhe

incremental cost effeCliveneSf; is also delermined for those alternatives on the DCC. The incremenlal cosl

effectiveness If; defined as lhe LTAC ofa given conlrol oplion minus the LTAC of an ullcmalive, divided

by lhe difference bClwcen the annual cmissions reductio,n (tpy) of the gi ven conlrol oplion and lhe

ullCrnalive being evalualed. The combim,tion oflhe,e two eC<lnomic analyses enn be used as an argument

for the eliminalion ofcontrollechnologies wilh sib",ifieanlly greater marginal control eOSIS lhun the givcn

ease. Thc equalion use<! ror lhe ineremenla] cost eITeclivencgs is shown below.

ICF = ,(l~"'~"~CL'-~L~'~"~C2!') (AE, -AE,)

Where,

rcI' = Incremcnlal COSI effeolIveness ($/incremental ton removed)

LTAC, Levellzed Tolal Annual Cost ofcontrol "llcrn"live No. l ($/yr)

LTAC, = Leve1izccl TOIUl Annual Cost orcontrol allernalive No.2 ($/yr)

AE, Control oplion No. I Annu;,l Emissions Reduction (lon/yr)

AE, = Control option No.2 Annual Emission" Reduction (lonlyr)

(Thc higher C;Qs~ mOre effective control oplion is subscripl I in lhis equation.)

The economic analyse, p,e,enled in this report nol only include the e,timated capilal and O&M costs for

each allemalive, but "Iso Ihe LTAC for economic comparison of lhc vnrions allematives. In addition, the

Unl! Control Cost or cost cf[ee!ivencss is presented ror each allcrna~ve_ Finally, a comparison between

alternalives, in lhe form of lhe marginal cosl effccliveness, is presenled in bolh numcrieal and gnphical

form. Thus a comprehensive comparison of the economic impacts ofcueh allemalive, as well as lhe

dilTcrcnce. in economic imp"c! bolween allcmalives is olearly presenled.

Cl-J Dums & MoDonnen
NOx BAcr Analysis Sn,dy

Table C.1·1 - Economic Factors(1),12)

TOlal Possible Ope,min~ Hnll'-' peT YoaT

Amort,zahon Life, YealS

C"'lorMoncy

Pmporty Taxc" Ill,urana;, '};,

Convc"i,m Tax (ill !lcu uf properlY lax)

Amorriza';on Ralc for APe Cap,lal CO.IL,

InLcTc." During COll,lmcllOn (me)

Di.<omml Role (llSe<! 10 calmlale NPY)

Com'rucli"" Cm! Escalalion

Non_Fuel O&M bcalallOn

Fuel (rualm<! nalllrdll;a,) bc.Jaliun

Aux,li.ry EIcciriG Power CU>I, SIMW-hr

Uroa COSl, ($/Ion delivered, 50% oqueO\l' SOIUlioo)

Nal",,,1 Ga, ($!I""ill"')

(I) All fl"nci,,1 pmcn,,'g,,-' on" "",I ,,,,,,r,",y ,lccle;" I'ow" co" wetc pmvLded by MI'C.

(2) • All co,,, ale io 2006 doll"" ""b, no,ed o'hrrwi",.

APPENDIX Cl

COSI Methodology

8,760

"

6%

N'

N'

c%

,%

6%

3%

25%

25%

$35.00

$380.00

$7.98

lJurn' & MGDon"dl CIA
APPENDTXC2

Capilol Cost E,~matcs

NUx BACT' Analysis Study

)"'.

C.2 NOx CONTROLS - CAPITAL COST ESTIMATES

The oapilill costs to implement Ihe various NOx walTol tcchnologies wcre largdy cslimllted from unit

oulpul espilal eosl faclon; ($/kW) published in technical papers discussiog Lhose conlrol technoiogie.,. In

the oases ofSNCR and FLGR, preliminary veodorbudgclory cosl infoffilalion WJa obhlincd nnd used in

ploe~ of, or 10 adjusI, Ihe pnhiished unil output co'l r.~clor<. ·lbese cost eslimale. were considered 10 be

~tudy b'flld", '''hich i. + or - 30% aecuracy, or herrer.

Thc hmilaLions of Lhcs" capital cosl e.timates developed from unil capil"l cos! fu"lors multiplied hy unit

outpnl arc:

• Scope hasis unoertainty - in"bilily 10 precisely delenninc whal scope ofsupply, including such

Ihings as balanee-of-phmt (BOI') aysle'TIIs and cquipmenl irnprovcmeTl\S w","e required, a",umed,

or accounled for when developing the unit cosl facLors. Some ullcmalivcs may have highcr

indirec\ or BOP capital costs Ihan others. Similarly, !he inchL.ion ofgeneral faoililic'S,

pre"roducLion and invcnlory eosls, and other indirect oos\S is not known. II is likely thallhe

ulility owner's fin"l lOlal expendilure for the implementaLion oflhe alternalives, especially

options that arc mosl eapilal cost-intensive, WIll be grealer Ih"n thc calculale'" cost eslimales.

• LocaLion-specific influences - mosl NOx control teehniques have been applied primarily 10

easlern hiluminous coal-fired planls localed near largc melropolitan areas, not in largely ruml,

upper midwcolCrn United SlaLes iocaies. Thc amount ofspace available is r1cpcndenl On lhe

exi.ting powc'TJllanL equipmenl ""d huilding layout and property plol area, vcrnuS what is

c~pecled to be rcquired for implemenling various comrol leclmoiogies. Tmnsportation and

local/regional labor costs are also variables.

• Size influcnoes - some leclmologies' capilal cost. are morc sensilivc to "economies ofscale"

than Olhers.

• Capacily margins _ some lechnologies' may require highcr capacity margin. 10 allow sustained

operation al high lhroughput rale. over exlendcd periods of lime.

• Reliability ConcernS _ SOmC lechnnlog'e.,' have b""T1 rcfined to a higher degree, and others may , require morc componenl redundancy Ibon olhers in order 10 avoid performance reduclions and

pUleotial oUlages for failures and repairs or replaoerncnts.

• Inflationary iLlnuences- Ih. significanL increases in 2004-2005 for mw material cll.SI<, especially

sleel and alloys for fabricalion of <tructural JTId rnc-chanical componenl', has occurred afier many

of Ihcsc teehnologies were inslullcd in projeots upon whioh Ihe rcfcn:nced unit capilal cost

faclors were based.

Minnkma Power Coop""'t;"e, Inc. Bum, & McDonnell
NOx BACT An,lys" Study APPENDIX C2

Cal,il,l COSI blim.les

• MarkeL condilions - as demand increase.' for emission controls, 'Om~ ahcnmtive., betome mOTC

cOSl_COmptlilive, whilc olhcTS <I" noL This can bc innucnted hy lhe rdalive supply and demand

for Ihc IGchnolog:y and number ofsupplie", who can rumish iL Thc <!cm"nd for ",me

allem"livc, e,m abo b<- sirongly influenced by the ,tringency ol-Iht luc"l, 'tate, and naliona]

regulalory reqlllrements_ Schedule for implemtnlalio" and availabili ty of loe" Ifrcgwnal labor for

in,lallalion eonlraolors are "Iso markcl-drivL'Tl [actor,.

TI,e e,limaled NOx conlrol co'L' ate in addl110n 10 eaplla] co,l" 10 provide ""rm"l rcpl"cemenl, of Ihe

exi,tiLl?, Mil10Ll R. YOtHlg Sialion's major power generaLing equiprncm.

C.2.1 Separated Overlire Air Capital Cost Estimates

lnslallalion ofscpar"led overfire air sy"tems 'Yf',cally indu<1e., windbox and/or ,econdory comhllslion all

,upply ducL modificaLlOll.S, boiler waterwall tub" opc"11ing:;, uirnow di"tribulLon deviccs

(damrers/regi>ler,,), airllow conlrol, oml rnC"Sluemenl instrument" lion, and rcbleJ ,lruelu",1 and

cleelri"alli~-Jnsto lk c,isling pl;lnl faeililies_ A basic sepamled ovcrfire air retrollI .'y,lem in"alk<1 on a

Iignile-fiIed cyclone boiler include, pOl'" acro,s the front and rear walls of the uppcr li,m"ce. The uml

capital cosL faclor '" expected to be above Ihc hlg.b end of Ih" Iypicul publi5hed e",1 r"nge ofS5-IGfkW"

($12.0fkW 01' $],080,000';; for MRYS Unil 1), uue 10 Lhe large duels, rdalively Lall furnace (compared lu

Iypical hilurnin",,~ toQ"q'n--u cyclonc boilers), and the need (0 avoid exi,ling oh;;buclions within Ihc

IloileI hou,c.

An advanced IOl'm nl- SOl'A unique 10 Norlh Dakota lignite-fiIcd hOller>; wlll include relocalion of Ihe

exi'ling lignil~ drying sysl= vcnt port openings from Lhe lower primmy furnace (0 the upper f"mace, to

be placed al Ihe same e1evalion as Ihe new SOFA ports. This require" exlen"ion orlhe c~istil1g cyclones'

lignite drying syslems' venL piping tn supply Ihc new boiler rumuec l'0rL'_ This i, expecled to cost in the

arca or +$4. 7/kW Or approximalely $1 ,100,OOIl fOl' Unil 1's additional eapllal co,t over and ubo\'" Ihe

b"sic SOFA system. Ovemll, Ihe advanced version ofsepara(e<! ovemre air leohnology '" eslimaled 10

bave on in'lullcJ capilal cosl ofapproximaldy $i6_6/kW ($4.JMillion) for MRYS Uml 1.

Dums &)o,kDorlllcll (;2_2 Mmnk<lla Pow"r COoporalive. Ino_
APPENDlXC2

Capital Co,t Eslimiltes

NOx BAC-r Analysis Smdy

C.2.2 Rebum Capital Cost ESlimates

".,

, , ':'"

C.2.2.1 Coal Reburn Capital Cost Estimates

There is One al~alive lhat includes a new coal rebum system. Capital co,t estimates for coal reburn

SYSlellL' are highly dqlendent on the rcquiremems for reburn fuel preparation nnd feeding 10 lhc boiler.

For the purposes of lhis "nuly:;i:;, the applicution ofa pulverized cnul rcbum system a5ffilmed the need to

make extensive ad<!itions to the existing fnel pr~"p""'tion equipmenl in lh. exisling; planl facililies ;md

feeding; to new furnace injectors. Al leasllwo new fim'-gril\d pulverizers, or MI'S-89 slandard

pulverizers followed by dynamic c1ussifi"rs are expecled 10 supply thc "mounl r>f fincly ground rebum

coal for lhis melho<1.

Addilion ofnew elecLriealload' for the pulverized coal preparnlion equipment to the exi.,ting plant

facililies will be required. For Ihe pttrposcs of lhis preliminary study_ il i" U8.Sumed lhat addilional plant

~uxiliary ekclri"ul power will be available for powering the new pulveriz£rs/mi~"To-milisan<! related new

coal rebum eqoipm~"Tlt, but Ihis has not been confirmed.

The. existing crusher roys do nO I have floor space available 10 allow the new mining equipmenl for rebum

fuel prepmmion to be localed adjaeenl lo Ihe eXlsling coal crushers. This will require a scpa'--dlC building

or gddilion lo the cxisl;ng powerhouse lo be buill lO provide suffieienl space to enclose the new milling

and coal silo/handling equipment. Separate modified pul~cri?"d co"l-slyle humer< or ooal injectors wllJ

be installed lhrough new opening:; in tho upper furnace fronl afid rear wal~T",all:; ut or ubove the elevalion

of the exi'l;ng lib",ile drying system VCTll pons, along wilh new overfire air pons IO<;alc"{) ill a higher

c!evalion, above the rebum fuel injeclors. This would have the capacity lo supply approximalely up lo

thirly percenl of the total full load fuel heal inpullo lhc boj]er Lhrough the coal rebum injectors. This coal

rebum syslem design was nul "xpeetoo lo change the exisling cyclone silo/feeder arrangemenl, such thal

all cyclones would remain operalional. To achieve maximum NOx emission control, only lhc a<!v~need

form of SOFA for pulveriz~-d coal rehum was included. Confirmation of these ooncepts and cosl

eSlimates require, more delailed equipmenl design and planllayoullhan has been performed for the

purposes of lhis BACT allalysis.

n,e insl"lkd capital cost ofpulverized coal rebum for the cyclone boilers al Milton R. Young Slalion

uscd in lhis cost effectiveness analysis was eslimaled ba:;ed upon a Clean Air Markets Division [CAMD]

of the US EPA dollar per kilow~tl unit capital cost faclor for cyclones. The installed capilal eO,1 eSlimale

of$21,900,000 for MRY Slation Unil l's pulverized coal rebum ultemalive used in lhis cost erfccliven=

analy,i< was estimalo<! oo:;ed upon applying a 3.5% assumed inflalion coSl adju<lmenlLO the CAMD unil

Minnkom PowerCOOperali,'c, Inc. C2-3 Bum' & MdJonnell
NOx BACT Analysi' StuJy APPEN])]X C2

Capital C"'l E"irruJlc.,

capiml COSI l"olOr for cyclones of$82.33/kW (x 1.035 = $gS.2/kW) ;ncludcd in a WRAP (Wc~[cm

Regional A;r J'artnersh;p) drnfl report~ puuli&hed On (h~;r website, dalCrl April 26, 200S. The cost to

relocale the lignite dlying sys!cm ~"Tll poTts (+$4.7/kW) was addcd 10 Ihc infl"lion-adju.'lCd CAMD

number ($S5.2 + $4.7/kW = $89. ~fkW), :;incc eo"l rcbum i, l'xpccl"d 10 incllllk scp"r:ated m'cdire ;1ir b"l

nnl the ex lm casts for lhc spceml improvemenls idenlilied tor a;r-'lagerl lignile-fJrinll in cyclone bOlleJ s.

This ;ncrcascd thc inslalled cap;lal cn,1 by SI,200,OOO for MRY S~lllon Unil 1', coal rellllnl sy,lcm [0"

to[al or $n,5(' I,000. This <locos nol include the additional l,al1icula,e ",otlel colleetwn capacny

consldcred nccc,,"my 10 limit Ihe expected Il~"alive imp"cl on opacily from Ih" opllOn.

To cOT,I",1 particulate matle, (PM) erni"lOns lhat would he expected 10 ;nerease Irnm inslaJlJtlOfi and

opCr.Jtion "r pulverizcd or micronize,1 coal rehurn, additional PM eolledion tapacilY w,nk reqUlrcd. A

hybnd form of PM collection Ihm supplemenls the cxi'lmg elcolrostnlic procipit"tor's performanoc,

rcfcn-c<l to as COHl'AC (COmpaclllybrid PArliculalc CollcclUr). ThIS 'vas cslimaled in 2002 ,Iullar~ al

S20,191,000 for MRY S[alion Unit I's COHI'AC. Adjnsted by an escalaliolllac[or of 1.2623, lhe

instullOd eopJlal cosl oflhe COHPAC "ddilioLl "lao cSlimated lO be $23,561,000 for MRY SLalioo Unil 1

in 1.006 doll.'I. Whcn Ihe COHI'AC addil"m "la, combincd w,lh Ih" Li!:oilc Rcb"", and ASOFi\

allemalives, lhe resulling lotal e.,[imaled c;lpltal cosls were $4(,,656,OUO for MRYS Unit 1 ($~9.~ + $~L7

~$IRI.5!kW)_

C.2.2.1 Gas Reburn Capital Cost Estimates

Convenlional gas rebum opllOns asoume lhal sevenleen pcrce--n! of Ihe lolUl ftlel heal illputtO the boiler is

lhruugh [hc HeW g", rcoum inJcclurs 10 he 100alo<1 in (hc lO"l<T 'ccomlary furnacc ahove the lOp rows of

cyclone.,. 6gbt 10 lwelve gas rehurn injeClor, would I,e expecled 10 he required llllhis tasc. Se,'en

pertent oflhe lolal fuel heal inpulln the boiler lhrough the gas rehul'Il injector, is assumed 10 be supplied

for Ihc liJd leoo ga' rehum all~TO;Jlivcs_ Four In eighl gu, n::b'lm injeclor, <Xl"I<1 be assumed ill l'I.G1F'"

cases. Gas rcb"m oplions assume lhat 0 new high-pressure gas pipeline would I,e hro"ght from near

1l ismarck, ND approximately twenTY six miles_ The pipel ioe diomeler ;s propnniooal to lhe amoum of

Iud required lor the s!",cific alLernatiw, nmging from 24 i,,"h~s ror eo"venlional gas rebum [0 12 j"ehc>

for fuel Jean gas rcbum Cil'CS. A sl"llion g"-S TillJin, wllh new gas trains, consisling of v"lve,;, melering,

and "..Iety shu toll valves for lhe froo! and rear Doiler ror the ga, injector,' s"pply, would he turni'hed and

inslolled.

Dllrn, & McDonnell Cl-'l Mmnko," Po""", CO"I'0mllVe, Ino.
APPENDlXC2

Capital Co", b~m",es

NOx BACf Analysis Srudy

I

I

I,

[:

eN

Thc capi!:ll costs for conventional gas reburn alternatives were cstimated considering unil capi"'] co.,ts

publishcd in published lechnicallilCrnlmc. Onc vendor lhal ha.' supplicd nUmerOl.l. domeSlic ulility boiler

gas relmrn sy,le= (GE Encrgy, formerly GE-EER) published $10/kW for gas rcburn in a 2001 technical

paper"_ Another SOUrce published a 2005 lcchnical pape," th"t provided a unit c~pilal COSl mnge for gas

rebum of$151kW to $30IkW. Neither source included a detailed scope desoription nor co.,t hreakdown

for engmceTing, cquipmenl, materials, and labor to inslall a !,'llS rebum sy,;lc"Ill.

Silc"spceific needs and challengcs identified for applying conventional gas rcbum to Millon R. Young

Stalion, and lack ofdelailed gas reburn projecl scope and cquipmenl de"criptiOIl£ available in published

leclmicallilermurc lead,; 10 a much greater degree ofuncertainty with regards 10 an accurale capilal cool

estimale for lhis allcmalive. For the purpose" oUhis study, the eslimMcd inslalled capilal cost for a

conventional g,.,; rcburn systcm Wilh advanced SOFA on MRYS Unit 1 is cxpecled 10 be approxim"tc1y

$9.9M ($38.6fkW), which is abovc thc lop cm! of the previously slated ran!,'C, before adding the new

underground gas pipeline capital costs. This study assumcd an average unit capacity capital cost factor of

$22/kW for conventional 8"" rebillTl, plus the additional co"Ls for the advanced from ofSOFA OVer ha.io

SOFA (+$L2M or+$>1.6IkW) and the new high-pressurc gas pipeline. This resulLs In a an cstim"tcd

installcd oapital co,;! for convenlional/ll's rchum systcm with advanced SOFA, on MRYS Unit Xof

SII.IM ($25_7IkW) plus the new high-prcssur~ gas pipelinc COSK ConfirmaLion of these concept!< and

oost e51imatcs rcquire" more detailed equipment design and plant hlyoutthan ha' been performed for the

purpose, of this BACf analysis_

Fuel lean gas relm'" (without SOFA) eapilal cost estimates wc,c based upon a late 2004 budge"'ry

proposal~' by a vendor (Fucl Tech) wilh experience in supplying FLGRTM equipment, typically combinc"

with an SNCR "y,tern_ Estimatcd capital costs of$3M includc \mdgelluy numbers for thc equipment

iosLaHatlon, including in$lallation mmagemenl, material and labur, wilh a --43% price adjustmenl

assumed for 257 vs 450 MW fur a fucl1ean gas rehurn sysLcm withoul SOFA On MRY Unit I, not

including lhe capital cost for thc gas supply pipeline. Co~ts for work outside the vendor's scope, suoh as

balance-of-plam addition, plus other indirect cosLs were estimatcclLO ~dd approximately $0_5M (25% plu,

10% contingency) to thc "djusted vendor's est;mUlcd installed co.,t of $1.7M for their scope ofsupply.

The"e adjustmenL. r"-'ult in a total installed capital cost for FLGR (without SOFA) eslimated 10 be $2.2M

plus the capital cost for the ~s supply pipeline. Adding the incremenlal costs for 11iC advanced from of

SOFA o,'CrnO SOfA (-I $4_JM (+$16.6fkW) results in an estirnalcd installed capital cosl for a fuel gas

reburn syste"Ill wilh advanced SOFA on MRYS Unit I of$6.6M ($25.7/kW) plus lb.e new high-pressurc

gas pipeline co,ts.

MITmko!3 POWCT Cooperal (ve, Ino. C2_5 Durn, & MeDonnell
NO, [lACT An,lysis Sn,dy APPENDIX C1

Capila] Coslll,!iITUllC.<

The capilal COSI el,lim~ les [or lhc new high_pressUl'~undel'ground gas supply pipeline nssumed $7 pel'

in~h u[ ,li"mclcr per foot of lenglh. This was calculated lu be Hppmximalely $23M [or convenliunal gas

reburning anu $11.5M for FLGR1 M. The co"1 analysi, [or each NOx COl\11'01 al temalive involving"

IKlL'liouln,· Ion" uf llns r~hum "ssmn"d Ih,,1 hOlh boiler>; ;'1 Mlltun R. Young Stalion sclecllhe same

all~m"liv~ Ih,,1 bums nalur"l gas_ Th~rcfore, Ihc c,lim"tcu cO]lilal eOSIS [01' gos rehurn allernaliv~< reflect

a capaoity-based I'fOl'0rllOnal ,hare of lhe gas pipeline cnl'iL,1 cn,L" avmulng uouble--<,ounting. Thi,

I'tsull, m "n eSlimal~d in"~,lku e"piwl eu,1 for MRYS Unit I', shure (lflhe ga, p;[,eline lO b~ $8.1M I for

Ih,· conwntional gao rcburn allernulive and $4M for fuel-lean gas rcburn all~rnajivcs.

The toLal in,lalled Oal,iLaI cO,L' fol' convenlional go; ",bum (wilh ASOFA) with MRYS UULl l's ohare o[

the lolal eupiwl cost fur 1hc gas supply pipeline eslimaled 10 be $18M ($70.6IkW). The IOlal inslalled

c"pirnl costs for FLGRTM (wilh ASOFA) with MRYS Unir I', .,hare oflhc lolul capital cost for thc gus

supply pipeline were eSlimaled to be $ IO.IiM (S41 A/kW). Con "rmarion of Illese concepL, anu cos!

eSlimalcs re<ju"cs mOre delailed eqllipment d~,ib'11 and planl layout lhnn ha< hee~ performed for Ibe

purposc, uf Ibi" BACT analysis.

C.2.3 SNCR Capital Cost Estimate

The allcl'l1alive, lhm include seleClive non_Ca!rllylic rc·ductlon sy,lenl, n,.<Ume the u,;e orlla',1 unless noled

ulherwi",. The SNCR syslems' preliminary desIgn and estimaled cupil"l eusl, WLTC bHseu upon a 450

MW lib'llile-fire<1 cyclone boiler in" laic 2004 blldgelary proposal' by" ,'enuor (fuel Teeb) wIth

experiencc in supplyin!l SNCR equipment. Circulalion, mete, ing, dilulion, conlrol, and injec!ion

equipHIOTll i, included. A I~O,OOO gallOI1 licld.er~"I"<! "Imnle" ,t<:cl .,wrage tank WIll hoM Ih<: 50% urea

.<ollJl1On (a, delive",u by lruck). lndi~ldlJal and multiple nozzle l"ntes wilh mulriple levels uf urea

reu!lcnl inj,·elion will b<. d~"b'1led "mllm;alnllo oplimize dlStribulio~ ;lnd aecommo<!nk various boiler

lond conditions. E.<timaled capilal co,c, of$4_9 Million intlude budgelary numbers for equipIllL"fI1

insl"1I"ll0n, including in'l,lIalion mnnagemcnl, malmnl and labor assumed lor a SNCR s}slcm applied 10

" 450 MW boiler. Costs [or work outside Ihe Vl"flUor'S scope, such ;'s olliduor rC;lgelll ,Iorage lank and

building enclosureiequirment foul1dalions and containmL"fII, ;llld halance-olCpbnt additions plus other

indireci eOSl' were estimaled 10 add appro~jrnmcly $1.9 Million (25% plus 10% cOlltingency) 10 Ihe

venuor', ~olimMed ins!ullerl CO,l for Ihcir scopc ofslIpply_ This results In ;In e,lim"leu lolal capital CO,1

for SNCll (wilhool SOFA) of$6.8M for a 450 MW lignile.fired cyclone boiler.

Hum, & MeDonTIelJ C2_(' M;nnko'a Pnwer Coope"'Livo. lno.
APPENDlXC2

Capital Cos, Es,in"lc,

NUx BACT Analy,i, Sludy

Ig

III

,

Applying these adjustmffil_ to 257 MW boiler, estimated direct capital costs of$2.800,000, plus

$1,000,000 for indirect cOSlS yields a totol inswllcd capital cost for applying SNCR to MRY Stalion Unit

1 ofapproximotcly $3,8]6,000 ($J4.9fkW)_

C2.5 Layered Technology Capital Cost Eslimates

Capita I costs wlTC gcncmIly e.' ~'nw l<:<l ",,'ed upo n ..,,;mple arithmelic addition of individual unit output

capital cost facio," for combin~tions of available NOx reduction tcchnologies, such uS SNCR with

ASOFA. An advanced foml ofocparated overfire air system includcd lhe ligmle-firc<l cyclone boiler

equipment changc:; within the estirn"tcu unil capital cm;1 [actors.

Adding the advanccd SOT'A capit.ul cost of$4.3 Million to thc prt:vious estimated inst.alled capilul CO,l of

$3.8 Million yields a total cslimated installed capit"1 cost of$8.113 Million ($31.6IkW) for th. SNCR

with ASOFA ullcmalive for Ml{YS Unil L

As prevIOusly disGu"Scd, Lignite (coal) rebum (CR) was us.sumed to be combincd with advanced SOFA

nnd a COHPAC addition consid~.,.ed necessary to limit the expeclcd negative impact on opacity from ibis

option. Thc inslallcd capital CO"t of lhc COIlPAC addition was estimalcd to he $23,561,000 for MRY

Stalion Unit L When the COHl'AC addition was combi"ed with tbe Lignitc Reburn and ASOFA

"llemati'lcs, Ihe resulting lOlal estimaled capital cosis wcre $46,656,000 for WtYS Un It I ($89.9 + $91.7

~SJ8l.5fkW)_

Minnkol, Power Cooperalive, Inc. C2-7 Burns & McDonnell

APPENDJXO

O&M C<>stE'~m3leS

NO"BACT Analysis Sludy

'.

iff<' 0

,

C"

0

..,

C.3 Operating and Maintenance Cost Estimates for MRY Station NOx Control

An evaluation was perfonned to <1~lcrrnine lhe esLim"tc-d operating and maintenancc co,t impacts of

inst<llling end conlinuomly operating various fC'llsib1e NO, control lechnolo!o,'ies on Millon R. Young

StaLion Unil I. These wcre estimatcd to bc in addition 10 cxisting O&M costs to opcrule and tlliIint<tin thc

MRY Station cquipment

The expected loss of electrioal power sales from Ihc operation of thc specific NOx control alternativc was

included as an nnnualized cost, assuming $35 per megawatl-hour. This was detcrrninffi to include

estimalcs for:

• Re<!u~tion in annual unit output due 10 an expeeted negalive reliability (i.e. uptime uvuilability)

impact for each alternative. This generulion rffiuction was calculated by multiplying the

esijma ted nddilional numbcr>; of outage hours per year by the UVerllge rmming plant capacity

factor for that specifio alternative, multiplied by the historic 12-month average unit grOSS

elCClrical pow"r OUlput (MWJ determined during the same period ~s the highest l2-monlh rolling

sununalion NOx pounds.

Net additional auxiliary clcclric power dem"nd for lhe added con Iro I equipmcn t lor eaoh specific

alternative boscd on assumptions for gross horsqlOwer, rlus additional power demand for exisling

f"ns cau<ed by l1uc ga, pressure drOp (COIl?AC for u<lditionaJ I'M colleelion oapacity), with

adjuslmcm for expected reductions in powc, demand (such as a decre""" in existing coal crusher

and feeder eleottic dem"nd for lhe pl,Jverizc<l coal rebum cJse).

The averagc wnning plant capacity factor for eucb altenlative, which 'nay also include all

expc"Clcd negative impaol on the unit capacity lrom oper"tion of the technology. This "","IImCS

that the control teehniquc limiL' the gross elcctrical power output ofthe Unit (such as causing In

inorease in flue gas flow) such lhat the firing rutc of the hoiler cannot be JlliIintained or raised to

compensate for thc load impact Example, are lowerboilcr lhennal cfficiency (highcr Unil heat

rate) when firing natural gas (due to highc'rmoisture contenl of1he flue g""s).

For the SNCR allernative thai involves a chc-mical reagent injected for NOx eonlrol, such "S urea, the

annual reagenl consumplion basc<1 on an assumed actual stoiChiometric ralio (ASR) ofmoles of

equivalcnt NH, injected per mole of uncontrol1ffi NOx emission estimaled "I the poinl ofinjection,

convertedlO a Illil-'"' rale (lb>Jhr) by multiplying by the estimated annual number of hours of operation and

thc eslimated NOx reduclion fraction, and lhen multiplied by unil reagent cost (for a speoifie inlet NOx

concentration, emission reduction percc"Tllagc and ammonia slip level).

Minnkola Power COOl'CRllil'e, hlC. Burns & McDonnell
NOx DACr Anal)"'i" Sludy APPENDIX ('3

o&M COSI Eslimalc.,

Geller.l anm,"1 mJintenJnce COSIS were assumed to be 1.5 perce", of the e3limaled inSlalled capi[al cost

[or each allernalive, exeepl [or [he co"1 conveying and grmdmg e'l"ipmcnl pori inn of Ihc coal reburn

alLem"livc, which was a"ullled [0 be 3 pcrecrtL The periodic hag replac~ment cosls ;ml1 other COIJl'AC

sys[cm mainLe""Tltc ~0"1, were es[imJted 10 he .pproximalely 5.J% o[ (h~ ms~,Jled capllal cost o[ Ih~

additlOn,,1 p"rlleula[e lllatl~1' oolkclion cquiprnenl.

Addilion,,] opcmling labor coms d'I'"~I]y allribulable to ea~h alLernmive were a<sumeu h> be zero for all

al[em"livc,.

Olher operating ~u,l, include:

• Reagenl dilulion waleI' for Ihose all~ma[ives lhal involve a chemieal reagenl inj"Clcd [or NOx

conlrol, !yplcJlly fOllr lim~s Ihe "mount orurea c",,"umpl ion (aosumes URa is a 5[)o/, solulion as

delivered and is mjccll-u "$ a 10% ,oJmion); this fonows EPA OAQI'S convention'.

• Heat I'equired for urea, eagem .'torage, for [ho~c ~lt"mJlives [hat involve a ohemlc"1 reagenl

inje~lcd for NOx COL\lrol; lhe ,ourec o[heat IS a.sullled lO he a""ili~ry ckclric"l power, hUl eou]d

be auxiliary ."e'm (lkpcnding on he~t .,ourcc avail.bility "",I planl preference).

• AddiIion.1 eool consumplion 101' lhose ul[emutivcs thai involve a chemical reagenl mjccled for

NO" conlrol 10 compens"t" for the heal ofvJporization ofIlle reagenl di1<ll;on waler;

This follows EPA OAQPS convention', hon if> not accep[c<1 pmcl;cc by an expenenced SNCtt

vendor (Fuel Tech) who claims lhal the hcul prouuccd fl'OJll the exo[hermic l'eoeLion of urea and

NO, i, approximalely equ3110 the heal ,c<juircu 10 evapora[e lhe dilu[ion waleL For [he purpo,",s

oflhis ,111.11', [his additional "0;,1 consllmp[ion has heen include,i in ti,e nnnu,,1 O&M co.'L'_

The sum of Ihe eslimaled annu,l1 o&M costs wa, "'ul liplied by Ihc O&M kveliza[ion :act,," ( 1.2~ 873) f,n

each alIen,all ve [0 yield leveh7.ed [lllol nnn,,"1 O&M cosl,.

C.3.1 Separaled Overfire Air O&M Cosl Estimate

Operalion of SOFA is expeclcd to add a small nmount ofO&M eosl, primarilyeleoIrieilY consumed hy

the conventional SOFA damper electl'io drivo aolualor and airl1mv measuring system lransnlitler on each

POlt. Using (he e""ling forced drali, im1ueed draft, and flue gas n,eirclllulion f;ms is not exrected 10

change Ih~ overall amount off"n horsepowe, d"'n"nd to k ~lIpplied by [ho.<e fans' eleclnc molol'a.

MamlO'anc. ofthe new overfire ",I' I,orts 'lOU relocalc<1lib'lli[e d,ying 'y'lem venl ports is included,

BUlliS & M,Donnell (,]_2 Mlmoko\a Power O>"ptrdllvc, Inc.
APPENDIXC]

O&M Cost E,lim,lo,

NOx BACT Analysis Srudy

,- .

~.

as.-'mmed 10 be 1.5 percent oflhe installed capital 0001. This is included in eve!)' oOIllrol allemative's

cstimaled O&M cost

SOFA is not expeoled 10 signi Ijcanliy reduoe unit reliability and availability 10 generale electrioal power,

assuming consistent combu"tion and "Onlinuous slag lopping under substoichiomelric air/fuel opel1lling

oomJilions for MRYS boilers can be roulineiy eslablished. A Unit a""ilabiJily reduction of2.2% (188

hours peryc"r), forM.R. Young Statiun Unit I was aB"umcd, which nllows for forced or exlcmkd

scheduled boiler oulages lhal may result from problemalic cyclone slag tapping operalional condilions

encountered during "UbSlOichiometric cyclone opcnllion with SOFA. The expcclooloss ofelectrioal

power ,",kB from the reduolion in nnnual electrioal powcr Olllpot due to a decrease in e>:pcclcd Unit

avaiiabiJily from ASOFA operation is included in every control ullcrnalive's estirnaled O&M cos!.

Boiler furnace walcrwall tuhe mainlenance nmy inerea.", slightly as a resull ofmOre fireside corrosion

due 10 substoichiometric cyclone operation wilh SOFA. TI,ere may be "orne ch~ngcs in the degrndalion

rale of thc boiler's furna"" w"I~'rWnll tubes resuHing from c:posure of more area of thc fumnee walls 10

sEghlly air-sl"rvcd conditions during SOFA operation. Such condilions can promole corrosiou from

"ulfur compound" in Ihe [urnace gaBes being crealed above the cyclones and below the SOFA injeclion

porl>;. Due lo lhe relatively moderate amounls of "ulfur contenl in the lignile, modes' amount or air-

.'laging oflhe e)lisling cycloncs during SOl'A operalion, and lhe potenlial use ofrecirculated flue gas

along lhe lower furnace walls, the e)lpec!cd change in corrosion rale ofthe boiler tubes should b. minor.

This degradmion is e)lpected to oc:cur OV~T m~ny years ofoperalion, and nonnally reqoires periodic

replaccmenl of the delcriomLed sec lions of boiler fumnce wale,w.ll tubes 10 avoid forced olltages to

repair lube leaks or failed "eelions. The additional 00"l>; assOCialed wilh potenlial change in lhe frcqu~'ney

offurnace wall!ube failures and ch"ngcoulS nre di rficuH 10 oslinmte, and have not been quanlified.

C.3.2 Reburn O&M Cost Estimales

The allcmalives lhal includc a new ooal rebum syslcru ","orne Ihe use ofnew equipmenl forprcpariug lhe

rcbum fuel to Tl.l'laee 25% of the MRY Stalion Unit I hoiJer's lotal fuel hCal input. Two additional

lignile silos, wilh coal keders and fjne"grind pulverizers followed by dynamic classifier(s), are assumed

lo be localed in a new separdtc boilding or powerhouse enclosure. Booster [an(s) add ilion wos included

because lhe existing forced draft fans were assumed 10 be incapahle supplying the nddilion.l amount of

primary air to lhe fine-griud pulverizers and dynamic cl","ifier{s) for processing and convcying lhc

rcbllm fuel. Using lhe exisling forced drall, induced draft, Jnd flue g"" recirculation fans iB not expecled

Minnkol. Power Coopera!i~e, Inc. C3-3 Burns & McDonnell
NOx IlACT Analysis Sn,dy APPENDlXCJ

O&M Cos! E"irno.'c'

lo ~,,,'Ilificanlly change Ihe overall amounl offan ho"epower demand 10 he ,uppl ied by Ihusc fam;'

electric motom. The expc'Cled loss ofelech'jcall>ower ,ale, from Ihe addillOnal auxiliary electric power

demand for Ihe rehum milling equipment ["rom an e,limnle,1 0.6% (1.5 MW) reduclion in nel O"lpul was

included a.' a cost, ",,"ming $35 per megawatl"hour for MRY S1a1ion Uml 1. Electrical rowe, oonsumed

by Ihe inercased load on boiler lims 10 OVCTcomc Ihe higher fluc ga, .'ysIem pre,,,rre drop, pIllS the

COllI'AC parrioula!e colkcllon syslem suppo,1 equipmenl W'S eslimaln] 10 he a 1.2% (3.2 MW)

,,'{luelion in net oulput for llnit I.

MainlcnaLlce or'lhe sepllr"le rcbum coal mjecrors, tiJe] ami pnmary air piping, and rehurn fuel millmg

equipme", i, e"peeled lo be similar In Ihc expenscs associalcd wIth typioal pHI veri'lcd coal burne". 'me

e,limllle,l,uldilional annual mai"l~n"ncc cosls for a new miclOnized cOlli [Cburn sy'lem was assumed lo

bc 3.0 percenl oflhe iLlslalled c~pllal cost, or roughly .~69J,OOO p'" ycar, for MRY Stalion Unit I, Thc

estimaled additional annual mllmlenance cosL, (in flalinn adj LL,Led [rom 2002 to 2006 $) [or Ihe CORPAC

'y,Lem was apl'ro"imulcly $1,223,000 tor MRYS Unil I. Boil~T fumace waLerwall lube and

,uperneulerfrehealer lube mallllenancc may increase slightly as a resulL ofmore erosion due 10 increa"ed

parl,culale em,ssions or [oHling by flyash depo5lts re.,ulting from 00111 [Cbum opera lion wilh ASOI'A.

The addilion.l cnsl, assucialed willi pntenlial change in the frequency of boiler rube fallurcs lmu

changcOI1I~ urc difilcult lo eSlimate, and h"ve Jwl bccn quantified.

The eslimaled impacl' on 0p","lion and lll.limenance en", lor 11lc cu"l rcbulll altemall..ell.aIineh..lc a

new pulverized or micrunized coal rebun, .'ySlem orc approx,male. The seve" (Unil 1) exi'llIlg coal

cru,he,.,; f'" preparing Ihc mai" (cyclone) luel fTnelion will have slighlly lower elcclrical dcmand. This

w~, e,llm"IL'{l us -0.26 MW (-(t I%) for MRYS Umt I. Addilion of new ekeiriclllloa<ls for Lbe

micronized coall'repamtion e'luipmenllo the existing planl faeihlJcs will be required. For the pUlpO,",S

ofIh" preliminary sludy, il is ",,"med Ihat addil,o".1 plonl auxiliary clecll icnl [lower will he llv"ilable for

powering Ih c no'v pld vmzerslcla", fLers and rclal,·u ncw co"l [Cbum equipmenl, bul Ihi, ha' not been

confinned.

Coal Rehum wilh ASOFA is nol exp-ected to "gnificlllllly rcduec Wlit reliabilily "nu availability to

g'cncrale elcciricall>ower, a""uming' eunsislenl comhuslion and oontinuous slag tapping under

substoichiometric air/fuel opernling conditions for MRYS boiler' can be roulinely eSlablishe,!. A Unit

a"allability reduclion of3.7% (316 hITJyr), lor M.R. Young Slalion Unit I wns a"umcll, which aHow.' Jor

rorcr:,l OT c~lenue<l scheduled hoilcr o\llagcs Ihat may ,.~.,,,llirom problematic operalionnl eondiliuru;

eneuuntered during coal rebum operalion wilh ASOFA. This r~ullction in annual e1eclrical power outpul

Burn' & McDollnell CJA MinnkOLa Po""r Coopcrali,'e, Inc.
APPEND1XC3

O&M Cosl Eslimalc,

NOx BACT Analysis Study

due to a decrease in expected Unit nvailability i, included in lhe coal Teburn control ahemalive's

e,timale<! O&M cost

A Running Plant Capa~ily Factorreduc!ion of0.5% of annual gross electrical oUlput was assumed for Ihe

coal rcbum allemalive. This would resull in an eSlimate<! 1.2 MW average load dl-cr~-ase forM.R. Young

Sialion Unil I. This expecled lo1.S of eleclrieal power sales from lhercduclion in nel outpul due to Ibis

planl eapacily impaot was induded in the estimaled annual O&M co,ls.

Convemional and fud-lean gu~ TCbum oplions wm involve higher operaling coSI~ compare<! wilh lhe

exisling operalion ofM.R. Young Slalion. N~luml gas supply w~s assumed lo be ~vailuble near

Bismarck, ND, but this has nol been confirmed. Tbc eSlimaled unit cosl of this natural gas was """,,limed

10 avernge $7.98/million Btu on a leveli7.ed annual cosl basis, wilh a "credil" of$0.71 pe:rmmlJlu for

avoided cosl of consumplion or lignile coal reduced by lhe nalural gus heat input. The e.,limaled annual

cos! of naturnl gas for lhe eonvenlional g;ls reburning aHemalive applied to MRYS Uni, l.is

approxim" leJy $29.7M per year. Tbe eslim~led an~u~I cost ofnatural g"-' for lhe FLGR"" allcmu!ive

applied 10 MRYS U~jt I is approxi""'lely $12.JM per year.

The new gas rebum injeelom, stalion gus main and injector gas trains would add a minor amouot of

expense 10 curreot maintenance reqoiremenls. ussumcd 10 be 15 percenl of the inslalled c.pilal eOSI.

Maintenanoe ofSeparaled overfire air nozzles is expeele<! 10 be similar to lhe exren""s assoeialed wilh

Unit Ts existing flue gas recirculalioo porK

C.J.J SNCR O&M Cost Estimate

The allemative., lhal include sdective non--cal~lyticreduction syslems will involve higher opera ling oosts

compared with!hc cxiSling operation ofMRY Stalion Unit.I. Ureu reagen' supply was oonfinned 10 be

available regionally. Thc estimated unil COSI oflhis 50% aqueous urea solulion Wll.'I assumed to average

approximately $379/(on delivered (2006$). Consumplion "furea reagenl fOl SNCR wilh ASOFA was

based upon preliminary numbers allowing for a boiler flue gas nil ammooia slip or5 ppmvd. These

W~Te CSlimaled as approximalely 200 gph for SNCR when applied 10 MRY Stalion Unit I wilh ASOFA.

New eleetricnlloads a,C required for high flow urea circulalion, in-line and storage mnk healing, waler

dilulion, and reagenl melering equipnlent. These auxiliary electrical demands and reagenl dilulio'n walcr

usugc were calculaled based upon equalions publish~X1 in EPA Office of Ajr Quality Planning and

Minnkol. Power Cooperative, Inc. Bum., & MoDonnell
NO~ BACT ATI,ly,i, Siudy APPENDIX C3

O&M CTI<T F'limOies

Sland.nJs (OAQPS) publication EPA/452/B..Q2-00 I, Sec lion 4.2, NOx Control., - NOx l'osl-Combmlion,

Ch"pl<:r 1 - Selective Non-Cal,lylic Oxid"tion'. Compres.,ed air fnr re"gent "Iomiz"lion "l<llancc

purgiLlg ,nd oooling, us well "s multiple n07,?Jc lancc wnlcr cooling ar~ mJdilionul dern"nds (In Ihe

exisling plant f,cililits. Th~~e p(Jwerhou,e buildi,,?, scrvicc ,uppli~, wen:: "s,llmed In be ,w"ll"bJe, bul

this lon, 1101 bcen confirmed. The n~w lire" reagent injection nozzle lance" rengenl pUl11pS, dilution w"tcr

pumps, and dlS!I Jbulion pipinWvalve train" would ,odd a minor ~mo""1 of ~xpen,", to c"rrcnt m"inlen"noe

requirerneTl~,","umed 10 be 1.5 percenl of Ihe inslalled capi!al cost.

SNCR with ASOl'A i, nol cxp~eled lo signJ ticnnlly reducc unit rdi"bilily and a~n, ];lblhly 10 gene role

deco·ical p<>wcr, ","uming urea injection doc, not impact the abilily to mainl;!in consistent comhllSliun

"Jld tnJltinuuu' ,lag tappmg under sub,t",chlOl11e,ric air/tuel operating con,lilions for MRYS bUlk". A

Unil "v"il"bilily reductioLl of3_2% (273 hrs/)'I), for M_R. Young SLalinn Unit 1 wo., assumt,l, 'vhich

"lluws for forced or extendcd schcduled boiler oUlages Ih'l may resull from problemnlic up<Tlllional

conditions encounlL'n::d dunng SNCR-re]alcd up<:l1liion wilh ASOFA. Thi, reduclion in ",mu.1 eleclric,,1

powcr OUlp,,1 due to a decrea,e in expcclcd Unit availobilily i, induded in Ihe Ihese mnlro] oltcnlll!ive:s'

~"linllll~J O&M coots.

A Running Pl.nl Capac;ly Faclor reduolion of0.15% of annual gro" electriclli olllpllt wa, a"umcd fur

the SNCR wllh ASUFA alternative. This would re,ult in all estimated 0_37 MW aye, age Inad dc""rc",",

[or M,It. Young S",tion llnil I. This ""peeled In" "r·elcclncal power &llcs from ll,c n"{luclioll in net

output due to lhis plnni c"p"cily impact was mcludcd in lhe eslimalcd llnnu,l O&M cosI,.

C.3.4 Layered Technology O&M Cost Estimates

Opera ling and m"i(Jlenance cost, for combin"lions ofavailable NOx reducli"n lechnologie, wen::

cOlimal",1 b",cdupon simple orilhmclic addilion of individual cosl e.<timalcs. SNCR \Va_ cumbmcd wlth

advanoed SOl'A, as previously shown_ Pulvcnzcd "oul rebum was assumed 10 be combined will>

advanced SOFA (lmd a COHI'AC addition [or I'M control). The auxiliary ckcmoal demands and rcagenl

dilulion \VUler u,ugc for SNCR wilh ASOFA were calculaled ba,ed UpOLl ""'I"alions puhli,htd in EPA

Offioe of Air Quality Plnnning "nJ Slandards (OAQPS) public"lion EI'N452iB_OZ--OOI. Section 4-2,

NUx Conlrols - NOx Pusi-Combuslion, Ch"plcr I _ Sdecllve NOll-CalalYlie Oxidation'.

Bum, & Mc[)o'lilell C3-6 Mi"okOla Power Coopetali"e. Inc.
APPENDlXeJ

O&M Co,t E,liTIllllos

NOx BACr Analysis Study

C.3.5 Summary of O&M Costs Estimates for MRY Station NOx Control

Thc rcsults of this evalualion for estimated vnliable opera ling and muinlcmncc co,ts for lhe individual

NOx conlrnl alternative., are summarized in lhis section. Thc cxpected redu~tiOl\s in Unit ~vailabi1ily

(uptime) and capacity are imludcd in Table, C.3-1 through C3-4 for MRYS Unil I. Tahles C3-5 and

C-3-6 for MRYS Unil 1 include lhe estimaled urea reng,ent and dilulion waler lL';age rates and COSIS for the

JltLTIllllivcs thai involve SNCR wiLh ASOFA NOx "ontrol te~hnologi"".

TABLE C.3-1 - Expected Availability Reductions for MRY Unit 1 NO" Controls

I':slimaled Annu.1 Ave<3ge Unit OpeT3lin~ Time

Unit Unit Unit

Operating Onl~ge Opera ling

Unit r ' T~~4, Time Redn<linn',

All.' NO"Cm.trnl Technique Avail3bility' h.'::"r ., hrsl r

, SNCR wI ASOFA 0_942 &255

'"' m

0 Ga, Robnrn wi ASOFA 0.952 8340

"" ,..

, Cool Rcburn wI ASOFA 0.937 8212

,

''" '"

FLGR wI ASOFA 0.952 8340

"" '""

A Advanoed SOFA (ASOFA) 0.952 8340

"" ,.. B,,-,eli~" 0.973 8528 m "

I Allom''''e n",~~er has boen prevlou,ly as"gned r,on, I.." renw",1 to h'gh""l ,emn••l pcrc<:111'Ce.

2 - 12·monL~ ~"ohnc ,v,ilat.ilily i' as'umed ,I 97J pc""nl. Th"" "Iu" 'eflocl <Sli"""cd ,mo""l' or"'glIlivo ,di.oiiiLy

imvoel expeclod [rom the implem"""tion or Lho indi'>'iduol NO. oontrol lcchn;qu".

l _ Annu,l operaLinB Lime is ,"n",1 avo"'go ,,,,,Habilily muhiphcd by 8760 h,,;lyr orvo"'ibl< uplime:.

4 - Annu,1 oul'gl: limo i, S76l1 h><lyr rn.~';hle opo"l;ng Ii"'" m;L1us esLimaLed annu.1 o[>OraLing lime.

5 _ Mnu,1 oporOling Lime mI"c,iou rC5ullin~ [rom lIlo implcmcn'.lion ortoe ,ndi,idu,1 NO, eO"',ollcehni4uo i, Ihe

<Ilff"ono<o """,oen Lho baseline ""d expocted allnual O"",g< Lm",s.

Minnkol. Power Cooperalive, Inc. C3-7 Bums & MoDonnell
NOx EAC[ Analysis Shldy APPENDlXCJ

O&M CO,1 E.>liIllal~

TABLE C.3-2 - Expected Capacity Reductions for MRY Unit 1 NOx Controls

() B P Y!?l g pc g

(2) 12_mo,"h h."I;"e n'nn;"g plonl cop,e;'y f""OT is "-'Surnoo al % (, p'''''.'''- TIle" ""h", ren,e' «'''""loo "IIlnun" of

",",,"ivo Toliab;lily irnpa" expecLed r,"m 'hc lmpl"""n'''li",, "flhe iotlivid",1 NOx contrnl '''h";'I''o,

0) - Annual dowie,'Y Ben"~L,o" ,.duel10" lS "no,,1 oper'ling 'ime roon"io1\ mnl'iplioo by 'h< .nonal nIJmins plan'

c"pll0ily lacL", ,,,,,llin~ from Ih, iml'lem",LaL,on "f 'he iLldivldu,1 NOx ,onl<ol ted"';'I'" mullil'lied by Joe 12-mon,h

,v,,"go gross OULpUL "f244.4 MW_

(4) _ Annual clceL""Ly go""aL;,m ,,<Iud;on coS! ;, 'he "0"",,1 decLric")" gcnerolLon redu"io" (kW-hTs/;T) rosulLJn£ r,,'m

Lil, Lrnpl'"'e"',,L,,,n "noe indiv;dual NO, "'''''01 Lechniquo mul"plled lly lI,e ",e"''''''',,1 ",Iue or el,w;cily

!:Onc,.",", .ssumoo Lo be S3,_UUlMW-I,,_ All <oS! f,gu," ,,' ~1li)6 <1"11",,,

Esl'IIlatcd Annual Aver.'ge Uuil Eleel.ioall'owor Generalinn

lIeduction fTORl'()I'OTaline Time R.dueli"n

Unit

Unil GeDer~l[on Unit G,"e,ali"n

All. Running Planl Red"olioll'" Rcdllct,on C"'ll'), L.bcl") NO~ Conlrol Techniqne Capadtv Faclor") kW-ln-sivr 1000.~lyr

C SNCR wi ASOFA 0_965 67,660,606 2.36~

D G., Rcbum wi ASOFA 0.957 16,120,681 1.614

C Coal Rcburn wi ASOFA 0.%1 /7,958,350 2,729

, FLGR wi ASOFA 0_962 46,400,200 1,621

A Advanced SOFA (ASOI'A) 0_966 4(,,5~6,546 1,631

Boseli"" 0_966

,

" "

AIL,rn"i"" de.,i naLio" ha< been rev,,"u,1 ,,-~<i,· cd fTOIll k,SI Tcrno"al '0 hi host n""o"l rocnLo e_

Burm & McDonnell 0-8 Minnk"lo Power COupLTILlive, I"c_
APPENDIX 0

O&M CO'IEslimare,s

NOx BACf Analy.,i., Siudy

TABLE C.3-3 _ Expected Auxiliary Electrical Power Demand Changes

for MRY Unit 1 NO. Controls

() g p y g g p g

m- The IIfC NOx equip,",,"' S""'" auxiliary elwrieol power d=aTId of.nemaLive, i5 lho sum orlndividual lechnolosi"

combined by simple add;lion. Ac'ual PO"'''' demand, may dilTcr from lhi, ~ti, '" po5Hive or ue~'live 'YlH:rgiSfio elToolsCoal robum i"d<Jd" 1,507 kW rOT feod p'''l',,,,'ion .nd eO"""ying 'quipmeoL d<,",md plu, 3,15~ kW for the COHI'AC

'ystem addition for PM CO""ol.

(J) _ ne APC NOx equipme"1 au'ili.ry eleonie,l power demand cred;1 of co,l "bum ,ltom"li", i, Ihe <>li""'too r~"1L or

lower "yolo"e 0001 prcparaTion and f" ....lor powo,- de"",n~ ~ue Lo lower bo,l" cyclon' 0001 equipmcoL loading. A"u,l PQ'''_~

d"m;od, may differ Iinm Lhi, due '0 =U"'CY o[ eSfi""'te, [or ...,onled .mounl o[ o!","'Ling hO"'j>OWorredu"ion_

(4) _ fl-,,-IOl,1 n, [auxiliary cb:lr1-e,) power d""'and i' Lhe_,um orrhc gmss dem'"" .ud credit

(5) - nc ""nu,l thange in APC NO, "'luipmrnt "u,iT;.<y <1<eI,ic.1 power dcman~ deeTdcity u"'ga io kW·h,.lyr for

thesc ,IL"""li"" i' Ihe 001 powcr dcm,"d muIL;plicd by 'he es,imaLoo an"".1 opcroti"g rime and mnni"~ planL

taraClly faotor which «""""the adjostmcn' for aoy c'peoLed rdi"bil;'y and e:ll"oi'y Im!",'"' rrom 'he

imrl,m"HaLion o[rhc oonrroll""hni~",_

(('J - '[he ,nm,,1 ,h,,"se in APC NOK equipment aoxil"ry elecLric.1 ...."'" deRland clc-cl,iciIY CO" i, 'he au""al d,.nge

in kW_h,s1yr [or Ih"", allem,Ii"''' ,e,oILin~ [(Om ,1,0 iml'l,mC"Latioo of Ih< individual NO, '"nlrollcohoi'IUO

mfliliplied by Lh, inOTcmcot,1 v,lue or "u,ili.<y elec'rioiry gelfe,.tio,,- ,ssflm<d ro he SJ5.00IMW·hr. All cost

figmcs i" 2006 <loll",.~

E.lima",d Anm'al Avn.geAPC NO~ E'luipmenl

AnIili....... Eledrical Power Demand "od Usaee

Gross Tolal Net Pow~r rower Usage

M'. Demand 1'1 C,edil'" I)emaud'" U,age'" Co,t'" •

L.bel'" NO~ Control Techllique "" 'W 'W kW_brsl r 100051 r

, SNCR wi ASOFA 73. I 0 73.1 532,411 "

D G., Reborn wI ASOFA , m (132) (1,054,J43) (J7)

C Co.1 Rebllrn wi ASOFA 4,6M

'" 4,405 JJ,905,082 1,217

B FLGR wi ASOFA , " (72) (578,744) (20)

A AdvaneedSOFA (ASOFA) , 0 , B.05S 0.'

, AI'<:mati,'< <I",i n"ioll "'-' boen fCviou,1 -, n,d ITom Ie"", "moval '0 hi h.,,;1 ""."vol ..,-e,n!a ,

MiTmkOfa Power Cooperntivc, Inc. 0·9 Durn' & MeDon""ll
NOx DACT An"lysis Study APPENDIXeJ

O&M COSl Eshm.le,

TABLE G,3-4 - Expected Auxiliary Electrical Power Demand and Generation

Reduction Cost Changes for MRY Unit 1 NOx Controls

() gn p y gig

(2) _ The ann",I chongo 1Il AI'C NO, equ'l'monl ,,,.iIimy dccLr;ea! I'''"or <lemaml dOdr;e;Ly "~ge io kW_I",Jyr for

Lhcse aloc,naLi"" " U" "eO r"W'~ ,Iom,nd muIllplied by Lho o'lim"oo "on".1 o!'Cr"<mg Lime ,od '""";Og plan'

edpa6ty f,eLor whi,h reDeelS Ih, adju"",e," for "ny "",!'C,oed r<liaLiH'y aod capaciLy impact< f",m 'he

impIemcnLaLron of Loe eon([ol Lcch";~"c.

(J) _ Ano",1 elw""Ly s,""aL"", ",I""ion is annoal 0I""aL;n~ L,me rOOl1e,ion m"ILipli,,j bylhe ,0nu,1 "mn;"g pI,nL

""J"e,'Y i"'lo, """I'ing from the implcme,"al"'" "f,he ind,vidual NOx eonLroI Lechmq"c ",,,IL'I'I,,,) b)' Ole 12_

monLh oYe'age gross OULruL "f244.4 MW.

(4) _ rile 'oLaI "'0;' ,lcc1r;",I puw'~ g,ncr,llion change ;< 'he '"m ofLho ,nLloal ChOllgC in I\PC NO, equipn"nl au,;I;.,y

elee'"e,,1 powor dem,nd elrerri,")' u",~e pi", 'ho .nn",1 clcc'nciLy genera lion rodu"i"n rc'"I1;I1~ from lho

;mpIemen"'L1DO of the indivJduol NO, """',,,1 teehnique.

(5) _ ·1 he loLal ",,;l do"",;,,,,II")"'« 8e"c~"ion ehonge co" L' Ihe lU',1 gencrallon ,honge (kw·hrsl)~) ",,,lripIicd b,' 'he

;ne,omel1l,,1 ",Iuc of e!C"';c;Ly gco""uall, a~,umc.:r Lo be SJS.OlliMW-hJ 1\11 cast Jigu'".1 J" 2006 doll"".

K,limaled ,\ nnn,,1 Cl,auge III Unil Gellerallun Due lu APC N(b

Equipmonl Aux'li.", P"",~r LltOlrj~Ily DelJ,and "lid Generalinn

Rtdutlioll

>eC Total U"il ,."lal Unil

Fle<lrkal Unil ~]eelr'c~1 P"wer EIeclrical Power

Po....er GCllerati"n Gm..-allon (;eoe,-alion

All. U<age'" Reducllou'" Chau~e''" Chaoge ('osl'"

Lahel"l NO~ Conlrol Teehlliq"e kW hrslyr kW_h.-.lvr kW.bnJ)T IOOOSI)'r

C SNCR wi ASOFA 582,41 I 67,66U,606 63,2<l3,UI7 2,3R9

D (;"' Rcburn wi ASOFA (1,054)43) 46,120,631 45,066,333 1,577

C euaI Robum wi ASOFA 11,9U5,082 77,953,350 39,863,432 3,946

D FLGR wi ASOFA (578,744) 46,400,200 45,321,456 1,604

, Advonced SOFA (ASOFA) 8,058 46,5R6,546 46.594,605 1,631

, AHem.,ived"", "ion h" ocen ",.io"-,I "-,,; nc.:r from leo" removal '0 hJ h,,, '0010",,1 '0"'111" ,

Burns & McDonnell eJ-lO MinnkOlO Powo, ('OOpc~"liyc, Ino.
APPENDIX 0

O&M Cost E,tim.te,

NOx BACT Analysis Study

TABLE C.3-5 _ Expected NOx Reagent Usage and Cost Estimates

for MRY Unit 1 NOx Controls

() s PYS" g i>CS

0) - All COst figure, in <006 dollar,,-

(3) - Rc,geoH diiuLion ,",,",r u,age """""',, po,"!>le waler is ,ddoo 10 """He, 10% "rca conoentrIli;on

(4 pons w"cr iu 1 part "rca solmion 3150% con,enL""ioo) I"ior '0 injoetion. D,luiion ",aLer un;[ """ a<.,u"",d

10 bn SUHl pcr ,h~u,and gall~",.

NO~ Reduction

NOxRcdoetion

Reagent Dilulion

Reagenl Ur.. U,~ge(l) Wain Usoge'"

Alt.

L~bel,n NOx Conlrol Tecbnique Jbsll,r tonslyr JOOO~hc JOOO ." JOOO~h , SNCR wi ASOFA 1,894 ',,," 2,861 7,232 ,

, AlLcJmti"e de,; nalion has been Jev;o"sl "",i ed f,om I""" JemO",I,o hi h"l ,,,,",val re,nLD ,

TABLE C.J-6 - Expected Heat Input and Equivalent Coal Cost to Evaporate

Aqueous Urea for MRY Unit 1 NOx Conlrols

() g!lll p y gn g l" gc

(2) _ HeaL ""1""00 to e"apo"'," urca re"~"nl d,I"';~n "",[or ."umes 900 B,wlb "'qllirai "'-,00 on °10% ",ea

eoncCTl'r.',"o (4 pans wo"r Lo I part OJea sol"'ion fil >0% eo"een"..;o") ;"j",,,,d for loe e"iLnaLed "m~""1 ~f

",ea usage. Coal heat roo"lenl 0[6,662 BLU~b. un;1 cu,l ufW.71ImmBlU.

Esfim~led Annual Aver:age Unit Equivalenl CD~I

Consumnlion CoS! for Ao":.eous Urea EvapoT;llinn . Heal Required In '&[oi"alent Coal

Evapnrale Consnmptinn fnr Coal Consumplion

All• Aqne01[S Urea"), Heallnpn(lll, Co,l'll,

Label'" NO~ Conlrol Te<lmique mmlilul r Ton." r 1000$/ , , SNCR wi ASOFA 54,315 4,077 "

, AltemaLjv, des; tioo h.. boeo rev;ou,l ." 00 [rom leaS! "mo".llo hi I,,,,, remowl rccnla

.~.

i

I;

1'=

,

Minnkol. l'ower Coope"'live, Inc. Cl_ll Bums & MeDuunell
APPENDIXCl

O&M eml ESlirIldlc"

Appendix C References:

;EI'A OHioe ofAir Quality Planning nnd SLarldnnh (OAQI'S) p"blic"\ion EPN45Vfl-02-00 I, Scclion

4.2, NOx ConlrOls NOx l'o'I_Comllmtion, Cllnpl'T 1 _Sclcclivc Non·C.I"lylic Rccl""liol1, daled

(ktoh~T 2000, po.<ted at lhcn wcb"ile: bJJp:!LW1if\v.eRa.gnv/un/calo/di, I/c.,4_2 ell I.I'dl; Ch"pler 2 -

Selectivc Calalylic Reduction, dnlccl Oclober 200U, posled at lheir websile:

h\to;IIwW'!'..epa.gnvIllnkn Icl<1 ir Iks4-2 cjl2oP't£:

" "SlulionalY Souroe NOx nnd PM Emi,sions 1I1 the VIR AI' RCll""': An Inili"1 A"cssmcnl of Emissions,

Con" 01" and Air Qlwlily ImpacL,", OCI"bcr 1, 20U3 We,lern Regional Ai' J'JJtner.;hip Final RqlOrt of

Ihc WRAP Market Tcading FOrtlrn, ~eetion VI: Summary of Emi,"ion Conlrol, AvaiJ"ble for' Larg,-,

~lalionary Sourec, "f NOx Jnd PM (by Rc"otion Enginee' mg Internalional), available al

hIIp:11""\'",..\\,rapa ir,~fg/lo I'llmsfmIPno:-;oPJl1.h1m1

,,; Bun]> & McDonndl inlernal dalaba.'e_

'" "Analysis of CombuSIioLl Conlrol> [or Reducing NOx Emi"ions Fcom Co;ll"fi"..l EGU's in the WRAl'

Region" WRAP nr~rr. Report EGR ContractNumbcT :10204-IOI, prepared by Easlern Re>enrch Group,

[nc., daled April 26, 2005, po"led allhcir websile;

hlt\l:!lwwv,'.wrapilir.on.:!forumsfsSlf/dooulnenl<;.!eicll>JNOxEljU/050426Cg~!::

fir'W%20EGU, in W,RAP Regjon-draft,pJf

, "C"mbustion MndJlicalion _ An Economic Al!em~li,'c for Boiler NOx Control" UElt_11 92 (04/01),

Folsom, Blair A, Tyson, Thmnn~ J. GE Po",er Systems, Schcpeclfldy, 1\ry, (001) POSll-.J at their' wcb,ile:

hllp:l/w.\VW,H~l)",\eL~"m,'pruJ,,,-,y/pmduol.,ilcol L J"cdCllldo\\'nlo"d~K~l~ IQ2.rdf

,; "A(,,,cssmcTlt ofControl Tec1mology Oplion, [or BART.Eligible Sourceo, Steam Eleelric Boiler"

llUlustnal Boiler", Cemen l Planls and Paper and P"lp hcililie'''' daled March 2005, po'ted ~l lhelr

we!>,ilC: hllp:i/bron:<~.n.c.,caom.o[ wcurnmillcl·'lh1lzeIlJART ,-"nlml A"C""'CIlI pd r

,,; Budgetary PmJ'0s~l, F"cl Tech, Inc. NOxOUT" SNCIl and SNCJVFLUR'" Syslem" lor One 450 MW

cyclone-fired <mil, claled Decemher?, 2004.

,;

Rum' & McDoonoll <:3_12 Minnkuill Power Coopcrdlive, Inc,