# • NOx BEST AVAILABLE CONTROL TECHNOLOGY ANALYSIS STUDY 10' 

# Miltan R. Young Station Unit 2 Minnkota Power Cooperative, Inc. Operating Agent for 

# Square Butte Electric Cooperative Owner

Revised Final Report 

## October 2006 31777 

# MinnkotaPower IMPel COOPERATIVE, INC. YourTouchstone Energy® Partner

# ~;~ 

# -NO., UACT A,wly,i, SLuuy 

# NOx Best Available Control Technology Analysis Study for Milton 

# R. Young Station Unit 2 prepared for


# Minnkota Power Cooperative, Inc. and Square Butte Electric Cooperative

October 2006 Project No. 31777 Revised Final Report prepared by Burns & 

## McDonnell Engineering Company, Inc. Kansas City, Missouri Tuble ofComelllS

COPYRIGHT 2006 '0 BURNS & McboNNELL E:-IGlNEERTNG COMPANY, lNC.

### Cha.pler Number INDEX AND CERTIFICATION
Minnkota Power Cooperative, Inc. and Square Butte Electric**Cooperat1VB-m~~** 

### Milton R, 

### Young Slation Unil2

### f~.SfJ 713 S 'OJ 

### No,; Best Available Control Technology Analysis Study ; ...

### ~' 

## .0**'Z~.** 

### Project 31777 

# fj "';**\~** (:**\'f~** 

# './ Report Index

# ~>c"<..**..v~y ";~**  

### ChapterTille Number ofPages 

# o 1 2 

### 3 Appendix A Appendix C Execulive Summary Inlroduction NOx BACT Analysis Sleps NOxBACT Analysis, BACT Recommendalions PennitLirnitRecornrnenualions Technical Details for NOx Controls AI-A2 CostDetails for NO>:: Controls CI-C3 11 

### 2 

### 6 50 

### 81 23 

## Certificalion
I herebyccrtify, as a Professional Engineer in !he slale ofNorth Dakota, that the informalion in this document was assembled under my direcl personal charge. This report is notintended Or represented 10 be suitable for reuse by MinnkolaPower

### Co~peralive, Inc. and Square Bulte Electric Cooperative or oLhers withoul specific verificalion or adaptation by the Engineer. This certification is made in accordance with theprovisions ofllie laws and rules ofthe North Dakota Slale Board ofRegislration underTiUe 28 Administrative Code.NO" BACT Anolysi; Study

-_.


# __ ... 

### _-_.

-----


### TABLE OF CONTENTS EXECUTIVE SUMMARY ES-l

1.0 INTRODUCTION 1


### 2.0 2_1 

# " " 

# ,., ,.;

3.0 3.0.1 3_0.2 

# ,., 3_LI 3_1.2 

# " 3_2_1 3_22 B 3.3. I 3.3.2 

# ,., 3.4. I 3.4.J.1 3.4-1.2 3.4-1.3 3.4.2 3_4_2_1 3_4_2.2 3.4.3 3.4.3.1 3.4.3.2 

### "TOP-DOWN" NO" BACT ANALYSIS APPROACH 2_! STEP I _lDEN1'lFY ALL CONTROLTECHNOLOGIES__

_ 2_1 STEP 2 - ELIMINATE TECHNICALLY INFEASIBLE OPTIONS

__ . . .2_3 STEP 3 -RAl\'KREMAINING CONTROLTECHNOLOGIES DY CONTROL EFFECTIYh"lESS .2·4 STEP4 - EVAI.UA TE WEMOST EFFECllVE CONTROLS AND DOCUMENTRESULTS 2_5 STET'S _SELECTRACT............................

. _.... 2-6


### BACT ANALYSIS forMRY STATION UNIT 2 NO"EMISSIONS 3-1 EMlSSIONUNITDESCRlPTION

.. _. . _ .3_1 :NITROGEN OXIDES EMISSION FOR,\{ATlON .-

_ 3·3 IDENTTFICATION OFNOx CONTROL OPTIO:NS FOR MILTON R_ YOUNG STATION 3·3 REVIEW OF RETROFIT INSTALLAnONS

.. .. __ __ 3-4 POTENTIALLY FEASIBLENOx CONTROL OPTIONS FOR MILTON R_ YOUNG STATION 3-5 FEASIBIUTY ANALYSIS.

__ __ _ 3-6 SUMMARY OF RETROF1T INSTALLATIONS OF NOx CONTROLTECHNOLOGIES

..3-8 SUMMARY OF FEASIBLE NOx CONTROL TECHNOLOGIES l'ORl\my STATION

_ .. -3_9 RANK OfTECHNICALLY FEASIBLENO:.:: CONTROL OPTIONS BY EFFEC11Vh"lESS. --3_13 ESTABLISHING BASELINENOx EMISSIONS FORRANIUNG CONTROL OPTIONS 3·14 ESTiMATING CONTROL-EFFECTTVEi'>lESS OFNO" CONTROL OPTIONS 3_15 NOxCONTROLSEVALUATION AND IMPACTSANALYS1S._

_ 3_20 NO" CONTROLECONOMIC IMPACTS FORMRY STATION UNIT L

.. __. 3·20 CAPITAL COST ESTIMATES FOR NOx CONTROL ALTERNA'fIVES

. .. _ .. 3-20 OPERATING AND MAINTENANCE COSTF.-STIMATES FOR MRY sTATION NO, CONTROLS 3-22 LEVELlZD TOTAL ANNUAL COST EsTIMA1ES FOR MRY STATIONNOx CONTROLS .3_24 ENERGY HvlPAcrs OF MRY STATION NOx CONTROLS.___

_ .3_31 ENERGYh\1PACTS Of SOFA TECHNOLOGY__

... .- 3_31 ENERGY IMPAcrS OF SNCR TECHNOLOGY 3-32 ENVIRONMENTAL IMPACTS OFNOx CONTROLS

- MRY STATION 3_35 ENVIRONMENTAL IMP-"crs OF SOFA TECHNOLOGY

. 3-35 ENVIRONMENTAL IMPACTS OF SNCRTECHNOLOGY___

. 3_36
Squan: Bulle Electric

## CoC~OoC,"""',"o----- TOC-I Dums & McDonnellNOx BACT All"l)'sJS STUdy Tohle ofCOnlen!,

3.4.4 SUMJl-1ARY OJ-**J:CU~OM1C,** ENLRGY Al':D**E?\VIR()t'-:~JlNTAL l~lPACTS**  OF :vIRY SI'ATION NU,CONTIl.OLS.

. ,-'.-' -. ,,3_37 3.5 BACT RECOM),-JENDATJON Al\D C();\ITROL**LEVEI~~** . MRY SIATION Ul':IT 2 ._ 3-39 3.5.1 WJT2NO,IHCT.**J.~.2** L"USSJON RATE LTh·IITATlON RECOM!l.Ill':DA']'jON

.. _



### APPENDIX A Technical Fea5ibility A5se55ment Detail5 for NOx Conlrols (A1) U.S. Coal Cyclone NOx Reduction Projects Summary and Relroflt NOx Conlrol Projects' Technical Literature Summary (A2) 

### APPENDIX B EERC Reporl- Ash Impact5 on SCR CatalY5t Performance (8)


### APPENDIX C 

### Cost Methodology (C1) Capital Cost Estimate Delails for NOx Controls (C2) O&M cosl EsI;male Delalls for NOx Controls (C3) _ _,--'10



## nun" & McDonndl TOC_' Sq"'",**B"lI~** Eleclric Cooper",i\',

### NOxBACfAnalysis Sn,dy


### LIST OF TABLES Table ofConlrnlg



## r:.; Table 3-1-Unit Design Parameters Table**3~2** 

### - Historical Avernge Lignite Coal Analysis Table 3-3 -PotentiallyAvailable NOx Control Technologies**Idcntifj~d** 

### for BACT**An~lysis** 

### Table 3-4

- Identified NO" Control System Retrofits on Cyclone Coal-fired Boilers Table 3-5

- Technioally Feasible Potential NOx ConlrOl Tcchnologios forM.R. Ymmg Station Unit 2 Cyclone Boiler Table 3-6

- Technioally Infeasible Potential NOx Control Technologies for M.R. Young Sl"tion Unit 2 Cyclone Boilers Tablc 3-7

- Ranked NOx Control Options l'easible forMRY**Sta~on** 

### Unit 2**Bojlerwi~l** 

### ExpeCICd Control Pcnorm:moe Table 3-8

- ExpectEd Annual NOx Control Perfonnance forM:RY Station Unit 2**Allcm~livcs** 

### Table 3-9

- Unit Capital Cost Factors ofFcasiblc NOx Control Option forMRY Slalion Unit 2 Table 3_10_ Eslimated Capital Cosls for NOx Control Allerrmlives

- MRY Station Unil 2 Table 3-11

- ESlimated 0&111 Cosl for NOx Control Altemalives- MRY Station Unit 2 Table 3-l2-Estimaled Annual Emissions a.nd Levelized Tot:ll AnnU"-1 Cost forNOx Conlrol Alternatives- MRY Slation Unil 2 Table 3-13

- Dominanl Coolrols Cosl Curve Points for Feasible BACT NOxAlternalives

- MRY Station Unit 2 Table 3-14- Estimaled Emissions and Economic ImpacLs Sommary forNOx Control AIlernative..,- MRY StationUnit 2 Table 3-15

- ExpcctcdAuxiliary Ekotrical Power Impacts for NOx Controls

- MRY Stalion Unit 2 Table 3-16 -Expected Electrical Power Generation Availability and Capacity**Imp~cls** 

### for NOx Conlro]s

- Jl,:lRY Stalion Unit 2 Table 3-17

- ExpectedTolal Electrical Power Generntionlmpacts for NOx Controls -MRY Slation Unit 2 Table 3-18

- Sumnmry ofTop-Down BACT bnpaclAnalysis ResulLs forDominant NOx Control A1lerna!ives -:MRY Slalion Unil2 Table 3-19

- NOx Emission ConlrOl Technology and Rale Recommended as BACT forMil!onR. Young Slation Unil 2 Table 3-20

- Recommended NOx BACT ConlrOl Method and JO-Day Rolling AverngeNOx Emission Rate Limil Withoul StamlpS Table 3-21

- Recommended NOx BACT Control Mcthod and 30-Day RollingAverage NOx Emission Rate Limil Wilhout Startups Table 3-22

- Recorrnnended 24-Hour Rolling Avcrnge NOx Emission Rale LimitDuring Startups

Sq=Bune Electric Coupcralivc TOC-3 Burns & McDonnellNOxBACT Analysis SlUdy


### LIST OF FIGURES Table ofCnnlenls

Figure 3-1 - NOx Control Cost EiIectiven<:ss

- MRY Station Unit 2 

### Figure 3-2

- 

### Mll.Y Station Unil2 NO

### x Control Alternatives Dominant Controls Cost Crnve 

### AppendixA1 Figure A.I-l

- Pulverized Coal Reburn Application Oll Cyclone BoilerWith Overfire Air Figure A. 1-2
- Natural Gas ReburnApplioation on Wall-Fired Pulverized Coal Boilerwith OverJjre Air Figure A.I-3

_ Hydrocarbon-enhanGoo SNCR Applioation on PC-fired Boiler Figure A.I-4 -Rich Reagentlnjeotion Applioation On Boiler With Overfire Air Figure A.1-5

- Conventional High-Dll5t SCR AIY3ngement with FGD Scrubber Oullet Reheat Figure A_I-6

- Tail-Gas SCRAmmgemCIlI Figure A_I-7

- Eleotro-Catalyrio Oxidation (ECO":> 

### Prooess Flow Diagram

Bums & McDonneR TOC_4 Square Butlc Ekcbio Cooperalive

### EXECUTIVE SUMMARY
The Milton R. Young Slation ofMirmkoln**PowerCoopera~ve,** Inc. (Minnkola) and Square Butte Electric Cooperative (Square Butte) includes two cyclone-furnace, lignite-fired steam-electric**genera~ng** units (SEGUs). The units both HreNorth Dakola lignite supplied from the adjacent mine, near Center, North Oakola. Unitl has a nomirml235 

### MW net design output capacityraling, is typically capable ofsuslained output oCapproximately 250 

### MW, (gross), andhas a gross design output capacity**ra~ng** of257 

### MW.- Unit 

### I is owned and operaled entirely by Minnkol!'. Unit 2 has a norninal439 

### MWneldesign output capacityrating, is capable ofsustained output ofapproximalely 

### 460 MW, (gross), and has a gross design output capacityraling of477 MW•. Unit 2 is owned by Square Butte Electric Cooperative (Square Butte), and opel1l1ed 

### by Minnkola_

A Nolice ofViolation (NOV) from theUniled StaleS Euvironmental Proteclion Agency (US EPA or EPA) was issued 10Minnkota Pow",: Cooperative on June 21, 2002. The NOV alleged thatmodifications badbeen made at the Milton R, Young Slalion thal would haverequired a**oonstru~lion** permil underNew Sourcc Review (Code ofFoocrnl Regulations 

### 40 CFR 52.21, andNorthOakola Administrative Code NDAC 33-15)_ N; a resnll ofthis allegation, a civil oornplainl was filed

### by the United States ofAmerica and the State ofNorth DakOla against Minnkota Power Coopel1ltive Inc. ("Minnkola'l and Square Butte Eleclric CO<JP""'l-tive ("Square Butte") in the United States District Court for the Dislrict ofNorth Dakola. A ConS","1 Decree (CD) has been approved !hal rcpTCsents a final negotiated settlement oflhe United Slates' and NorthDakola's claims againstMinnkota and Square Butle. The Consent Decreerequires Minnkota and Square Butle to perform a**"NO~** Top-Down Besl Available Control Technology (BACf) Analysis" 10 descnlle lhe emission limits for NOx ilial will be required at Units 

### I and2, expressed as a 30-DayRolling Average No" EmissionRate [ConsentDecree paragraph 24, page 

### 7, and paragraph 5, page4].

Bums & McDonnell was retainedto conduct a Top-Down BACfAnalysis for nitrogen OJ;ides (N0x) al lhe Milton R. Yeung Station. The results cfthc BACTanalysis 

### arepresenled in this stucyreport
TheprocedllTes mandated by !he ConsentDecrce forperfonninga Top-Down BACTAnalysis are outlined in ChaplerB oftha U.S. EPA's New Source Review Workshop Manual: Prevention of Significant Deterioralion and Nonattainment Area Pennitting, Draft. October 1990 ("EPA's NSR Manual'l 

### The MRY SlationBACT analysis was performed in accordance with this procedure_ The

Square BUlle Elcclric Coopemive ES-l Bums & McDonnell

### Execurive SnmmaTy NOx BACfAnaly,is Study

EPA's NSR Manual outline, five**basi~** 

### steps that are Lo 

### be followed in this BACT analysis. These hasie steps for such a BACr analysis are summarized as follows:
Step 1

- Identify All Control Technologies Step 2 - 

### Eliminate Technically Infeasible Options Step 3 - 

### Rank Remaining Conlrol TeGhnologies by Control ElTeGliveness Stcp 

### 4 - Evuluale Mo,l ElTeGlive Controls Jnd Document Resull' Step 5 - 

### Select BACT



### A BGsl Available ControlTedmology (BACT) analysis was performed for Millon R. YoungUnil2 for NOx 

### using the EPA's '"top_down" approach_ Rest Avaikoble Control Technology is defined as "an emi"ion, limitation (indmling" visible emission standard) based on lhe maximum degree ofreduclion for**c~ch** 

### pollutant subject to regulation under AGtwhich would be emitted from any propose,l major staliomrry SOillGe or major modjfiGation whichthe Admini'lmtor, on a Gase-bY-Gase basis, taking into account energy, cnvironmenrnl, and economic impacls and other costs, determines is achievable for such
source ormodification through application ofproduclionprocesses or available methods, systems, and techniques, including fud c1c.ning or treatment or innovative fuel oomlmslion teGhniques for control of such pollutant" (40 CFR 52.21, 

### NSR Manual Kll_

Unit 2 

### alMiltonR. Young Station is a 

### cyclone-fired boilerthathurns North Dakota ligniLe_ Themelhod offiring is very signifioant in analyzing**~ontrol** 

### options for NO

### x emissions. A 

### cyclone boilerproduoes inherentlyhigher**un~ontroned** 

### NOx 

### levels Ihan pulverized-cool and circulating fluidizedbedboilers. There have been nO new cool-burning cyelone-fircd boilers built and installed in the United States sinco the early 1980's. Consequently, there are no examples ofBACT eOnlrol options Iisled in Ihe RACTfBACTILAER Clearinghouse**datab~se** 

### for**eonsid~·roLion** 

### and direcl applicalion ofpubJishedNOx emission permitlimits On the Millon 

### R. Young cyclone-fired boilers_
Step I 

### IdenlifY All Conrro] 

### TcchnoloLries The ConsenL Decree requires lhallhe NO" Top-Down BACT ALlalysis for Lhe MillOn R. Young Station ··inclnde an evaluation ofSelective**Ca~1lylie** 

### Reduction (SCRl, Selective Non--eatalytio Reduction (SNCR). Overfire Air (OFA), 

### Rioh Reagent Injection (RRI), 

### as well as otherNO" control technologies" polenliallyapplicable for lignite-fired eydone boilers [Consent Decree paragraph 65, 

### page 19]. Olber 

### idenlified control teohniques, such US 

### fuel switching and fud de"ning, rnd combustion-related emis..,ion GOntro] lechnologlcs, such as 

### fuel reburn and oxygen--enhanced combustion, wcre also**~onsidcrcd.** 

### Bums & 

### McDonnell ES-2 

### Sq""re Butte Hemic Cooperative

### NOll BACT AIIillysi, Study Executive Summary



### Step 

### 2 Eliminate Technically Infeasible Options The BACfevaluation detennined tbatnot allthc teclmologies identified were considered available and applicable_ The technically infeasible alternatives were eliminated from further evaluation, along 

### with feasible technologies willi economic impacts that were unreasonable compared to other cost-efficient allemetivcs to control NOx 

### emissions forMRY Station Unit 2.



### The technical feasibility ofapplyingNOx emission reduction techniques and technologies alMilton R_ Young Station is dominaled by the composition and combustion characteristics ofthe North Dakota lignite supplied solely from a surface miue adjacent to

### the plant. This mine is the only supplierofsolid fuel for this station, as there are no railroad fucilities provided

### to servioe the Millon 

### R Youngplant. North Dakota lignite has high moisture and high 

### sodium content, moderate higherheating values, and can have a widely variable "nd high "shcontent comp..-cd to 

### othercoals. Those characteristics create difficulties in promoting consistent, steady combustion and slag formation in the cynlone burners. 

### It also results in produning a :Oyash that has severe deposition oharacLeristics.

Bothboilers inclnde a unique coal conditioning system 

### (drying, crushing, and feeding) for each cyclone furnace specifically designed to aid in proper combustion ofthe lignite fuel. This method offiring solid fuel significantly influences the resulting nitrogen oxide concentration ofthe flue gases emitted from the boilers.

Ash 

### deposition in eachboilerand air preheater is a significant operational challenge for !he facility. Significant equipment and manpower resources 

### are devotedto on-going-removal offireside ash accumulations. Unit outages mustbe conducted atregular inle:rvals to 

### clean each boiler(approximately every 80-120 days). There 

### are a numberofissues thatmake selective catalytic reduclion (SeR) tedrnically infeasible fer NOx emission control forMillon 

## n. Young Unit 2. 

### The consistent long-term operation ofSeR teclmology on lignite_fired cycloneboilers will be drastically inhibited by the susceptibility ofthe SCR catalyst

### to severe [ouling, deactivation, and erosion resulting from the actions ofthe emitted fiue gases and lly"sh, and ashdepositremoval operations_ SCR technology is considered techninally infeasible for application on the cyclone boilers allhe Millon R. Young Station.

Rich Rea.gent Injectionhas been demonstmted on boilers burningbilumiuous ami subbituminous coo.L However, it has not been cornm=ially installed and placed in continuous operation on a cyclone-fIre<l boilerburning lignite coal wilh high fouling and slag temperature sensitivities associated and a highly
SquaTc 

### BUlle E1ecrrk 

### Cooperative Bum< & 

### McDonnellExecutive Surrumry No"BAcrAnalysis Srudy

variable heat conlent. RRI adds urea rcagerrl to lhe hot furnace**~"'$CS** near the cyclones,**whi~h** must be devoid offree oxygen 

### in onlcr to avoid oxidllliorr ofthe urea, andthus**~reating** No",. While 

### RRl is**speoifi~aHy** intended for NO

### x emissions control on cyclone boilcr" 

### RRI is oonsidered teohnieally**infca,ibl~** for applicmiorr Orr lhe lignite fired cyclone boilers at the Milton 

### R. Young Stalion due to Ihe variable**he~1** conlcnl oflbe 

### 1ignile fuel which allows lhe**~realion** ofoxygen-rich conditions in the boiler.

The application o[**separ~ted** overfire air (SOFA) [orNOx emissions**~onlrol** on Milton 

### R. Young Unil2's boilerwas evalualed as part ofthe BACT**3n~lysis.** 

### A version ofseparated ovemre air specifically designed [or increasedNOx emission**redu~tion** perform_nee for**lignit~~fired** eyelone bOllers, referred 10


### as "Advauced SOFA" in this**~nalysis,** can be inslalled on bothunils at 

### M.R. YOlmg Slation. This highest-performing form ofSOFA cUI! bc npplied alone and in combinalion with olher lechnologies. Key aspecls ofsuccessfully applying and operaling a sopamte<! overfiro air ,)'Stom On a cyclone-fired boiler

ore the abilily 10:

• Aecuratelymeasure lhe fuel he"l inpul ratc (BUTs) and**~ombuslion** air inputs on a real-lime, individu_1 cyclone by cyclone basis, to allow the ability to determine and controllhe desired airffuel ratio, especially when '·sl"rved air" (i.e. subsloichiomelric) combuSlion conditIons are required.

• Maintain adequate molten coal a"h (slag) formalion und Dow wilbin thc bmrels and slag taps.

The degree '0 which the individual cyclone firmaoes can be operated with lcos"lhan-lheoretioal**(,ubsloiehiom~lric)** combustion air, which corresponds to operation ofa SOFA sy"cm, direclly**~olltribnles** to less combustion-relaled NO

### x formation and fUrll,er in-furnace emission reduction but also risks solidifiealion oflbe molten ooal ash. This places great emphasis on**aehic\~ng** tight conlrol over lhe air/fuel <alios on each cyclone during air-Slaged**~ombustion** operalion 

### w-iLh SOFA 

### in order [or uir·slaged combustion to be**suc~essful** in producing significant addilional NOx emissions reduction on lignite-fired cyolone boilers.



### In the C"se ofMRY Station Unil2's boiler, air-staged oombustion muslbe sufficient 10 reduce NOx emissions while releasing enough heat to continue to mell the fuel"m so that it Dows effectively within 

### amI from The**~yclone bllIIT~TS.**  Due to the short"tenn variability oflhe combustible amI ash componenls of NorlhDakota ligni1e supplied from the currenl mine near Cenler, 

### ND, and The complex behavior oflignite ash when exrosed to high lemperatures, the exlenI ofair-SlUl,rlng andlhus lhc level ofNOx control while op<:raling thc highest-performing version ofSOFA system is expected to 

### be modest. . 

# ,

,>

Durns & McDonnell ES-4 SquareBuneElectric Coop=!ivcNO" BACrAnalysi, Study ExecutiveSummary

i"

.. , 

# ,. Selective Non-Catalytic Reduction (SNCR) technology

### has beenused to reduce NO" emissions 

### on
numerous utility boilers bumiog eastern bituminous coal, midwestern bitumino\Js coal, and, to a l=er extent, western subbituminous cool. SNCR has also l>een used on fuel oil andnatural gas-firedunits. SNCR does not appear to be dependent directly 

### on the type ofbumers (wall-fired, tangentially-fired, and cyclone-frrccl) employed in the boilers where 

### ithas been installed, with or without air-staged combustion with overfire air in full operation.

There are significant conocmS associated with effective long-term SOFA operation forMillon R. Young Station Unit2's boiler_ The ability o£hasic combustion equipment:md improvements to precisely
measure the boiler's heat input rate in real-time on an individual cyclone by cyclone basis with compensation for the short-term variability ofthe combustible content ofthe Center lignite to consistenlly mainmin subsloichiomcmc operation o[evcry cyclone during air-staged combustion is unproven.

Severnl other techniques and teohnologies were considered technicallyfeasible for NOx emissions control at 

### MRY Station: Fuel Blending/Switching;**Basi~** Comhmtion Control Improvement,>; and various forms ofFuel Rebum. Fuel swilchinglblendingwa, not evaluated further becuuse ofexpected unreasonably high capital and operating costs and no additional emission reduotion compared to continued lignite firing.**Oth~rNOx** emissions controltechniqucs and technologies for 

### MRY Station that Wore evaluated and determined to be teohnically infCilsible were: Fucl Cleaning; Low NOx Burners (LNB); Flue Gas Recirculation; Oxygen-enhanced Combustion (OEC); Water/steam injection {combustion tempering}; and Electro-Catalytic Oxidation (ECO"'),
Step 

### 3 Rank Remaining Control Technologies by Control Effectiveness The third step in the "top-down" BACTevaluation ranked the remaining control technologies by effeetivene.'<S_ The purpose ofranking the control technologies was to establish a hierarchy thatplaces at the "top" the control technology that achieves the lowest emission leveL 

### The technologies in order of their effectiveness, from highest to lowest, are: SNCRwith ASOFA; Gas Reburn with ASOI'A; Lignite Reburn with ASOFA; Fuel Lean Gas Rebum with ASOFA; and Advanced Separated Overfrre Air (ASOFA). None ofthese control options has been installed on a cyclone-fIred boiler burningNorth Dakota lignite. k; such, the expressed control percentages reflect the 

### use of**enginceringjudgmen~** based
on the listed technique or technology application_·
Squam Bull<: Eloctric Cooperalive Burns & MdJonndlExecutive SmmnaIY NOxBACT A11lIJy,;s Sluuy

SleD 4 Evaluate Mos! Effective Controls**~nd** Document llesulls Additional criteria besides technical feasibility were utilized for technology selection in this BACT analysis, These included estimates ofcontrol effectiveness (i.e.**PLTC~"Ilt** pollutantremoved), capital plus operating and maintenance cosLs, annual emission reduction (tons peryear), energy impacts, avernge**~m]** imremental cost**effec~veness** ($/ton), and environmental impacts (other media and emissions oftoxic and hazardous airpollut:lnLs)_

The economic analysis examined the capital cost ofeach fea.<ible BACT ahemative evaluated and:my otherpowcrplant upgrade costs necessary 1.0 implem"Ut the**altcm~live_** 

### In addition, the economic analysis examinedthe operating and maintenance cost associated with the highest-performing forms of each feasible BACT aHemative evaluated. These costs were then combined into a leveliud tolal annual cost [or a**comp~rntivc ~sscssmCJlt**  ofthe lotal implementation eost ofeaoh**aHem~li"e.** Finally, 

### as part of the lop-do'Ml analysis, a domimmt controls cost curve was plotted JIld the unit control cost for each alternative was evaluated.

Two alternatives were on the dominant controls cost curve and thus were identified as the more cost dIcctive 3ltcrlwtiva. The two 

### BACT NOx cuntrol nlternntives evalunteu for incrementnl cosl, energy, and environmental impacts applicable to Millon R. Young Station Unit 2were:

• Selective Non-Catalytic "Reduction (SNCR) combined with a special 

### form ofseparated ovcrfirc 

### ,iT (SOFA) specifically for lignite-fired cyclone boiler.; (referred to as Advanced SOFA or ASOFA); and

• ASOFA alone.

The two most cost-effective reasible control altematives [orreduction (lfNOx emissions wcre reviewed to delcrminc ifthc USe ofthe technique or tcchnology would resull in any significant or unusunl energy penslLies 01'benefits_ Potential inerea<e in power plant energy consumption or net generationreductions, for ASOFA alone, Or ASOFA with SNCR were relativcly small.

The prcdict<:d**~"Ilvironm"T1lal** impacl.5 from**impl~'IIlen!ntion** ofthe two most cost-effeGtive feasible NOx emissions control alternatives from slighllyhigher unburned carbon in Ihe emitled fly ash, carbon monoxidc, and exccss anmlOnia ("slip") emissions WdS expected to be small in comparison with the

Burn. & McDonnell ES·6 SquaTO Butte Electric Cooperative

### NO" BACT Analysis Study Execulive Summary



### .'-' significant antioipaled reduction 

### in far-field ozone and improvement in atmospheric visibility as a result oflhe overall 

### NO" emission reduction.
Slep 5 Selecl BACT Taking inlo account technical feasibility, energy, environmenml, and economic imp3cts and othereOSl5, the recornmen<!C<1 BcstAvailable Control Technologies and associated emission rates for nitrogen oxides emissions produced hy Millon R. Young Slation Unit2 boiler-are provi<!cd in the table below.


### NO

### x Emission Control Technology and Rate Recommended as BACT

Control TechnoloQV and Emission Rate Recommended as BACT 12-Month Rolling Average Unit Pollutant Control Method 

### NOx**EmISSlon;~~le** (Ibl million Btu Selective Non-Catalytic 

# , NO, Reduction with Advanced 0.330 Separn.ted Overflre Air 

### (ASOFA)

This recommended BACT 12_monthNO" emissiou rate is based upon a historicpre--eontrol 12-montb baseline average atmual 

### NO" emission rate used in the control and c05t--effl.'Cuvencss analysis of0.786 IbfrrunBtu for Unit2. 

### The baseline emission 

### was determined from the t2 consecutive monlhperiodwith thehighest historic summation of

### NOxmass emissious (pounds) reported for actual operntionbetween January 1,2001 and December J I, 2005.

To complete the 

### BACf delennination process, the Consent Decree (CD) requires that "spccific**~outrol** teohnologie:s 

### to be installedand a specific 

### Phase II 30-day Rolling Average NO" Emission Rate limitation (lbs/MMflru)" mual be establisbed for each subject emissionUnit [CD Parngraph 66, pg 20]. Because lhere are expected tobe minorshort term variations inopernling conditions whereMinnkotahas not, in fact, materially changed any oflheir nonnal daily operatingpractices, a margin betwcen the 12-monlh average operating conditions and the 30-day pennitiimit 

### is proposed This recommended ernBsion rate should be suitably highersueh lbat operation consistent with the technologicallimiLalions, manufaoturer's specifioations, and good engineering and maintenance prnctices 

### to the extentpractic"ble for the recommended

### NOx BACTalternative wonld no! resultin an exceedarrce (violation) oran enforceable emission permit limit.

Square Dune ElectricCooperative ES_7 BlUm & MoDonnell**Ex.cu~ve** Summary NOx BACT Analysis Slndy

The Consenl Decree also requires that the North Dakota Departmeot ofHealth's (NDDH) 

### NO, BACT Determination ad<lrcss specific**~-mis"ion** limitatiOlls during Unit startups atMilton R_ Young- Station [CD Paragraph 

### 66, pg 

### 20]_ "The type and duration offiring dnring startups, and the limited ability ofavailable and feasible technologies to conlrol startup NOx emissiOlls, both significantly influence the 30-lIay rolling average BACT NOx emiS'lon rate limit recommended for Millon R. Young Station boilers. A 24-hour rolling**~v~"'gc** NOx emissionrate limit applied 10 startup periods is also recommended for Milton R. Young .'ltation hoiler<_

The SEGU startup operatmg period is usually not defined io emission permits. However, for Ihepurpose ofthis 

### NOx BACT analysis, DnH startup 

### was defined as thcperiod from initial fud combustion to the point in time when:

• the measured Heat Input to the boiler on a 6-hour rolling average basis is grealer lhun or equ3lto 4800 million 

### BTUIhr for Unit 2; Or

• Ihe 3mount oftime reported for the longest individual Unit 2 startup period during actual operution hetween January 

### 1, 200111I1d December 31, 2005 elapses, whichever occurs first; or

• fuel.firing is discontinued prior to satisfying either previom criteria_

For IMRYS Unit 2, the recommended 30-day rolling average 

### NO" emission permit limitraLe 1hal includes the impaot of.,tartllps is based upon recognized operational faclorS and C<juipmentdesign, that influence whether the startup emissions rcsull in**high~"r** 30..lfay emissions compared to normal continuous operation excluding such startup periods:



### • The uncontrolled emission 

### I'ate (i.e. without separated 

### OFA or SNCRin**op~-ration)** .nd its variability during operatiOll from a cold startup up to and includingmaximum continuous rated output;

• The operating conditions thal are required to exist for the seJected NO

### x BACT controlledmiqucs 10 be initiated and 

### be effective; and

• The elfectivem:ss ofllicse two particular contmltcchnique, ifinvoked at less-than-MeR steadY_slale operating conditions.

6 The number ofstartups ana Iheirrange oftypical dumlions per 30-dayperiod time frame.

TIle Consent Dccrec and thc 

### EPA's NSRManual do not describe the method for determining a 30-day Rolling Average 

### NOx Emission Rate pennillimitalion 

### (CD Phase II) thai rclkcl<

### BACT applied to Millon 

### R. Young Slation Unit 2. The approach taken in this analysis was to establish a historic pre_ control 3D_day baseline avcrageNOx emission rate (lbfmmBtu) from the**~O-consecutivc** day period with

Bll"'" & McDonnell ES_8 Squarenune Eleotric CooperaliveNO" BACT Analy,i, Study EXeaIlivc Sununary

the high""thistoric unitNOx mass emissions (pounds) reported fbr actual operation between January 1,2001 and December 31, 2005. This re[\ecls unit

### NO

### xemissions that**W~'re** generaled during periods of high unil operations, nut alTectedbyunit shuldowns, startups, or malfunctions. This'was then compared to the 12-monlh hi,toric pre-control baseline average NO x emission rale (lbfmmBru) from the 

### 12- conseculive nlOnth period with the highest historio unitNOx mass emissions (pounds) reported fur actual operation during the same 5-yearlook-haekperiod. An estimate ofNOx emission reductiuu forthe proposed BACTNO" alternalive operating at the**~is[oric** pre-control 30·day baseline average NO" emissionrate 

### (lblrnmBtu) was made. This rale eoru:ideredreoognized uperational faotors and equipment designs applied 10 "swady state" conditions with sustained oUlput close to JrUlXimumcontinuous capacity ratings. Thepotenlial 

### impactofstartups, Tecognizing; operalional and leclmicallimilations onNO" emission control performance, was then applied to lhe steady-slate rate, to eslablish a recommended 30- day Rolling; Average**NO~** Emission Rate permit limitation (CD Phase II) that 

### reflects BACffor Millon R. Young Slation Unit 2. This is summarized below.

.•. " 

### Recommended NOx 

### BACT Control Method and JO-Day Rolling Average NOx 

### Emission Rate Limit Without Startups
30-day Rolling Average 

### NOx Unit Pollutant Control Method Emission Rate limit Excluding Startups (lbfmllUon 

### Blu) Seleotive Nou-Calalytic 2 

### NO, Reduction with Advanced 0.350 Separated Ove:rfrre Air (ASOFA)

This recommended BACT 30-<iayNOx emission rate limit jg based upon a historic pre-contro130_day basehne average NOKemission

### rate of0.874 lb!mmBtu- for Uuit 2_ The baseline emission 

### was determined from the 30-consecutive dayperiod with the highest historic unitNOx emissionsrate reported for actual opel:ation between Jan",,-r)' 1,2001 and December 

### 31, 2005.



### An inoremental adjustment to the proposed 30-<iayrolling average sleady_state unilNOx BACTemissicn rale wlthcut slartups of0.35 IbfmmBtu forUnit2 is recommended for the 30-day roUing average NOx emissicn permit limitperiods 

### as dermed and applied tu Milton 

### R_ Young Station. This is .untIrulrized in the table below.

SquareBullo Elcctrie Cooperative E8-9 Durn< & MoDonneil**NO~** BACT Analy.,i, SLudy Ro"i,od IGil 7/2006

Recommended BACT 3D·Day Rolling Average ND

### x Emission Rate Limit and Startup Impact 30-day Roiling Average NOl( Impact on 30-day Roiling Unit EmissIon Rat" Limil Average NOx Emission Rate Excluding Startups Limit Due 10 Slartups (Ib/million Btu) (lb/mlllJon Blu) 

# , 0.)50 +0.102 perslartup**Thi~** recmnrnenued .djushnent to the propo,ed 30-day rolling: 

### avcra.Bc sloOlly-state NO

### x BI\CT orni"io[l**ral~** limil t"ilho,,1 ,("rlup" is ba,ed upon average hismrie pro-control NOx emis:;ion "'lOS of0.959 lb/mrnllru for ULlil 2**rcport~d** for Ino lungesl in,liviulml Unit 2 starrup period doring nemal operation belween January 1,2001 al\d December 

### 31, 2005. Tnc,e omi"iollS occurred during the lil-ho,lr Oember 25-30,2001 'larrup fo[ Unit2.



### A**2'~-hoLLr** rolling avcntge 

### BACT NO

### xomission rate limit applle<! 

### lO 51al1Up**r~riotl;** i,**~15o** rceOlllll\cndcu 

### tor eaeh ofthe I1--lillon R. You<\g SLalioJl b"ll"".
Thi, i, ,umm"[ized 

### ill rhe lable below.

Recommended 24·Hour Rolling Average 

### NO

### x Emission Rate Umit During Startups
24-hour Rolling Average NOx Unit Emission Rate Limit During Startups (lblmillion Btu) 

# , 1.064**The;;~** elll«,lon, "c""mod during- lhe ll5-hour October 25-30, 2001 'tartup for Unir 2.
Compliance wrrh**(h0.'~ ~,ni"siOL\**  [HlC wou 1,1 b" m",,,,un;,1 "I the ,mck ofthe Uni[, verifLeU wilh Can\iLllloUS Emi"s;oLl M"Jlitori"g- (eEM) ,y,IGnl, in ""ouru"ncc with Ihe**rder~nce** melhods ,pc"if1e<l in 40 C-F,[t. P"rl 7j. and woul<l he determine<! on a 30**CO"'~"Uljve** Or"ntling I);,y ,md**24·""n5""utiv~** hour wiling ;I\'''nt)':e lJa,;is,**r",p~otivdy** ES_IO Rllm, & \kJ)onndlNOx BACTAnalysis Study Executive Summary

A trial demonstrationperiod oflB months after the completion ofConsentDecree Phase 

### II NO

### xemission rednclion system Installation oommissioning al Millon R. Young Stalion is recommended. 

### It is proposed 10 allow Minnkota (for Square Dutte) to demonstrate the actlml control syslem capabilities oflhe combined NO

### xBACT emissions reduction syslem. Operating experience during the trial period will:

• confirm steady...state control performance ofthe combinedNOx BACT emissions reduction system;

• allow deterrninntionofthe ability to further eonlrol Unit start-up emissions;

• allow lhe detennination ofthe permitted 30-<lay rolling average NO

### x emission limitincluding slartupS, shutdowns, and malfunctions; and

• address the specific emission limilations during Unil starlups at Milton 

### R_ Young Slation and their Impact on lhe proposed 30-day rolling average emissionrate limit (wilhoul slartups).

Based upon tho informalion obtaIned during the !rialperiod, final emission limits can then be detennined.

The means that will be employed 10 minimize emissions during st:lrtup will primarilybe based on operntingprocedures, bothbefore and after lhe level ofupper furnace gas temperat\IrCs and/orheat inpul raT>: are considered sufficient 

### to slart the NOx controls and opernling conditions are conducive for effective emissions reduction. These could be similar lo Minnkola's current MRYS practices, orcould

### be different, depending upon the capabilities ofthe NO

### x controls 

### and lheir impacts On Unil opcrations_

Square Bulle Eloolrlc Coopemlive ES_ll Bums & McDcnnel1NOx BACT An.ly,is Srudy



### 1.0 INTRODUCTION Introduction

The Milton R. Young Slalton ofMinnkota Power Cooperative, Inc. (Minnkola) and Sqllllre Butte Electric Cooperative (Square Butte) includes two cyclone-fum.ce, Iignile-ftred boilers producing sleam for electric generation. Bo!h unils fire North Dakola J\gnile 5llpplied from an adjacenl mine, near Center, NorthDukola.

A Notice ofViolation (NOV) from Lhe Uniled Slates Environmental Proteclion Agency (US EPA or EPA) 

### was issued 10 Minnkota on Jlllle 21, 2002. TheNOV allcged that modificalions have been made at the MillonR. Young Station lhut would rcquire a conslrnction permit underNew Source Review (Code of Federal Regulations 40CFR52.21. and North D.kota Adminislr.l.tive Code NDAC 

### 33-15). A!iJ. result of this allegation,' civil compl.int was filed hy!he United Stales ofAmerioa and the Sl:Ile ofNorthDakol•

•gainst MiIUlkota Power Cooperative Inc. ('"'Minnkota') and Square ButteElectric Cooperative ('"'Square Butte") in thc United Sl:Iles District Courtfor lhe District ofNorthDakota_ A ConsentDecree' has been entered thatrepresents a final negoliated settlement ofthe United Stales andNorthDakota's claims allainsl Minnkota and Square Bulle. The Consenl Decree requires Minnkota and SquarcBultc 10 perform 3 NO

### x "Top-Down" BestAvailable Control Technology (BACI) Analysis 10 describe lhe emission limits fOT NO

### x thatwiH be required atUnits I and 2, expressed as a 30-Day Rolling Average Emission Rale (lb!<lmilJion Btu)'.

Bums &MeDonnell 

### was retained byMiIUlkola 10 conduct a "Top-Down" Best Available Control Technology (BACT) Analysis for nitrogen oxides (NO,,) at lhe Millou R. Young Sllltion. Bums & McDonnell is a full service engineering, archilcclUr1ll, eonslTuction and environmental firm. The company plans, desigtls and constructs electric generating facililies and has beenproviding environmental services sinee!he 1970s. As part oflhose services, Bums & McDonnell has extensive experience in pennitting, Besl Available Control Technology (BACT) shIdies and control lcchnology analysis. The results oflhe BACT analysis 

### are presented in lhis 

### repon.

1In lheUoiled SI<lles Di'trict CourtForThe Di'triotOfNorthDakota. Uni<ed Stales OfAmerica and Slllie Of NorthDakota, Plaintiff

.. y_ Minnkota PowerCooperative, Ino. andSquareButwElectrio Cooperative, Defeod.o". Civil AotionNo. I,06·CV_034 2 !bid

_ foolnole number I, CD paragraph 65, page 19_ SquareBulle Electric Cooperative Bums & McDonnell

### Introdnclion NOx BACT Analysis Slndy



### The primary guidance ulilized in 

### preparation urthis IlAC[ analysis is lhe U.S. EPA's New Soure" Review**Workshop~Manua]:** 

### Prevention orSignitjcanlDeterioralion and NonatUtinmcni Area PenniUing, prafL Octoher 1990' ("NSRManual").



### Tn Ihenexl seelion oflhe report, lhc approach 10 

### the BACT 

### Analysis is de'crihed. Following lhal, a quick sunumry orlhe planl eondilions alld repon basis i. given and 

### then lhe BACT 

### Analysis begins. The impact portion ofthe rcpon is broken down inlo "'parJle subsections. Within the last section, lhe results Ol

### an oflhe BACT

### Analy.is sleps**~rc** 

### "uuunarized forNOx 

### conlrol oplions for Unjt 2's boiJerat the Mihon 

### It. Young Slation.

J ChaplITB nflhe U.S. EPA's New**Sourc~** ReviewWork,hop Monu.l: Prevention ofSignilio.ntDelmorationand NonaH"jnrnonl Aroa Porrnitting, Draft, Oolobor 1990.
Born. & McDonnell Square Dune 

### Elootric CoopcTative

### NOxBACfAnalysis SlIldy ''Top.Down''NOxBACfAnalysis Approaoh


### 2.0 "TOP·DOWN" 

### NOx BACT ANALYSIS APPROACH Best Available Control Technology (BACf) is an emissions limitation for eachpollutant from a source detennined to be achievable using controltedmologics(s) thaIprovide l11e '"maximum degree ofemission rcduclion. _.taking into accollllt energy, environmental, and economic iIIlJXlcts''''. A BACT revicw docs not resull in an 

### emissionsremoval efficiency requircmcul. The generany accepledprocedures for performing a BACf analysis are outlined in the EPA's draft NSRManual. The BACfanalysis for Milton 

### R. Young StatiouUnit 2's boilerNOx emissions was performed in 

### ac:cord"nce with this procedure. The EPA'a draftNSRManu"1 outlines five basic steps that 

### are to be followed in the "topdown" BACfevalUlition_ These steps are as follows:
Step 1 .-

### IdentifY All Control Technologies Step 2 - Eliminate Technically Infeasible Options Step 3 

### -RaukRemaining Control Teohnologies by Control Effectiveness Step 4 - 

### Evaluate Most Effective Controls and DocumentResults Step 

### 5 - Select BACT

Thepredefined steps ofa BACT

### analysis are 

### described in this section, and results presented. Available NO

### x control techniques and**le~hnologies** 

### are defined, identified, and a technical desoription ofthe emissionreductionprocess and capabilities 

### are reviewed in the following section. Subsequently, those teohniques and technologies deemed feasible forretrofit application 

### are mnked aocorrnngto nominal NO

### x control capability. An engineering analysis reviews the estimated capital aud operations and m"intenance (O&M) coSts for each feaslble alternative, including taking a look at Balance ofPlant (BOP) requirements. Following thc cost impact determination, the energyand environmental impacts are 

### reviewed foreachfeasible technology. Finally, the rC5lllts ofthe engineering analyses 

### aretabulated and a NO

### xBACT selection isrecommencied for each 

### unit.


### 2.1 STEP 1 -IDENTIFY ALL CONTROL TECHNOLOGIES The first step in" ·'\op-<lown" NOx BACT 

### analysis is to 

### identify, for the emissions unit in question, a comprehensive list ofall**~available"** 

### conlTol options. In the EPA's draft NSRManual, "available control options are 

### those airpollutiou control technologies or 

### techniques with a practical potential for application to 

### the emissioTlS unit and theregulaled pOHulaullffider evaluation. AirpolJution oontrol technologies and techniques include the application of

• lliid foomore tmmb<r2, 

### NSRManual B.t 

### SquareBun. Electrie Cooperative 

# ,., Borns & 

### McDonnell'Top_Down" NOx BACTAnalysisApplOad. NOxBACTAnaly,is Stnrly
production process or available melhods, systems, und technique." including fuel cleaning
or trcalrncnl Or innovative fuel combustion**technjque~** for control oflhe affected poHulant'"

. According; to lhe liPA's amftNSRMmJual, "a teclmology is considered "available" ifit call be obtained by the applicant througl1 commercial**~hannels** or is**Olhcrwi~c** "v"ilablc wilhiu lhe common**sen~e** mcaniug; oflhc tcrm''''. Also, "a coutrollechniqne i. con.idered available, within the GOntelltpresented above, ifil has reached [he**licen~ing** ana commercial sales slllge ofdevelopment"'.



### In order to idenlify available NOx emission control technologie., and techniques appropriate forpotenlial application to 

### MRY Slalion lUlits, lhe following information sources were reviewed for coal-firedelcctric generating unit powerplanls:

• EPA's RACTIBACTILAER Clearinghouse (RBLC) database and Control Technology Cenler (websile)_

• Federal (TiPA) and**Slal~,** inc1llding North Dakola Department ofHealth internet**web~ilcs** 

### for air emISsion permits and recenlly-.nhmitted applications, inGluding; BACT Ev"lnutiOlls following; New Source Review**pro~edurcs.**

• Federal (EPA ami Department ofJu.tice) and State, includingNo.ih DakOlll Dcparlment of Heallh internet website, forCOnsem Decrecs issucd**a~** a rc,"lt ofIcgal actions takell by lhe United States goVcmmclll for alleged violations ofthe Preventioll of**Signili~anI** DelCIioralion (PSD) provisions "ml Ncw Source Review provisions ofthe Clean Air Acl, amllor fr:derallyapproved and enforceable State TmplcmcnlatiouPlans.

• Control technology vendor informalioll_

• Publishcd and**~vailable** infonnatioll from technioal, engilleerlng, ana enviroumcnlal oonsul1ants_

• Technical literature found injournals, reports, internet websites, newsletters, proceedings of technical seminars aud conferences pertaining 10 sludies, engineering, designs, and testing of

### air pollution controls_

, Ibid, NSRMorn"l B.5 'Ibid, NSRMauual B.17

, Ibid, NSRMornlOl D,13

BurR< & McDonnell SqLJllIC**Bu~c** Eleenic CoopcrnliveNOxBACf Anal,!,is Study ''Top-Down'' NOlI BACfAnalysis Approach


### 2.2 STEP 2 - ELIMINATE TECHNICALLY INFEASIBLE OPTIONS The second slep ofthe "lop-<lown" BACTprocess is lo cvaluate the availahle NO", eonlrol technologies nnd techniques**iden~fied** in Slep 

### I in lerms oflhe specific factors that apply lO lhe emissions unit in question. 

### In**accord;;mc~** wilh EPA's draftNSRManual, "an available teclmology is "applicahle" ifit can be reasonably installed and operated on the sourcetype under consideration. 

### A technology lhat is available and applicable i8 ledmicully feasible'''.

TheEPA's NSR Manual slales a technology maybe determined lobe not applioable if"a technical assessment consideringphY8ical, chemical and engineeringprinciples and/orempirical data showinlllhe lechnology would not workon the emissions unilunderreview Or lhal unsolvable leclmical difficulties wouldpreclude the successful deployment ofthe technique"·. Also, a "showing ofunresolvable technical difficulty wilh applying the control would constitute a showing ofteclmioal infeasibility (e.g., size oflhe unit, localion oflhe proposed siLe, and operatingproblems related 1.0 specific circumstanoes oflhe source)"l'. 

### Ailc:ra determination is IIUldc lhat tmy oflhc processes areteclmically infeasible, options are eliminaled iftechnical challenges would preclude orprevenl lhe su=fullong-tennuse oftile control option or technique on lhe emission unit under consideration_ This is perf=d prior (0 any economic analysis.
However, lhe EPA's NSR Manual also stales

.....control oplions incapable ofmeeling an applicable New Source Perfonnance Slandard (NSPS) or State Implemenlation Plan (SlP) limilwould notmeet the defmition ofBACf lIndcr any circumsLances. The :lpplicant does not need to consider them in lbe BACT analysis"". Also, it states 

### uAn NSPS simply defines lheminimum1cvel ofcontrol Lo be considered in lbe BACT analysis"". The NSR Manual further stales "When developing 0 list ofpossible BACT alternatives, lbe only reason for comparingcontrol oplions to an NSPS is to determine whether the oontrol oplion wouldresuIL 

### in an emission level less stringent than theNSPS. 

### Ifso, lhe oplion is unacccplnble"". New Source Perfonnance Slandards (NSPS) forNO

### x emissions from EGUs firing Norm Dakola lignile
are O.8IblmmBlu_ The EPA Acid Rain Program's Title IV No" cmission limitfor Group 2, cyclonefIred coal boilers wilh outputs greater than 155 MWe is O.86IbfmmBtu.

, Ibid, NSRM'lIU.l B.17

, Ibid, NSRM.m,.l B.20 '"Ibid, NSR Manual B.I9 11 Ibid, NSR Manual B.12 '2Ibid, NSRManual B.12

" Ibid. NSRManual B.12 Squarc Bull" Eloolric Cooperative Bums & McDonneU'Top-Down" NOx BACTAnaIy,I' Appro"ch NOx BACTAnnl}'sI, Siudy

EPA's drnft NSR Manual also slale" "A Source wonld not be required to experience exlended lim" delays 

### or resourcepenallies 10 allowre,earch 

### to bo con<luclo,l On 

### anoW loohnique. Noilher is il expecled that 

### an applicant wuuld bc required to experience extended**tri~ls** to learn how to apply a lochnology on a loja]]y
new and dissimilar**~OllICC** typo. Consequently, lechnologies in the pilot scale testing stages of deyelopmenl would not be considered available for BACT rcyicw"l<.

Also in lhe EPA'5 draft NSR Manual i:; a 'lu"lilicalion for technic"l fc"sibilily,"s describedby lhe slalemenl "Commercial availability by itself, howeyer, is nol necessarily a sufficientbasis for concluding
a lechnology to bo applicable "nd therefore teclmioal1y feasible. Technical fca:;,bilily, as delermined in _,. Step 2, also means a control option may Tca"onably be dcployed on or "applicable" to the souree type under considcralion"".


### 2.3 STEP 3 - RANK REMAINING CONTROL TECHNOLOGIES BY CONTROL EFFECTIVENESS The 

### lhird**s(~"p** in the "lop-down"' DAC[ evaluation is to rankthe eomrol technologics rem"inillg allerth" feasihiliry analysis hy conlrol effeclivoncss. The purpose of ranking the control technologies is lo eslablish a hienrrchy that ')Jlaces at the**'~op",** lhc**conLrollc~hnology** mat achieves the lowest emission leyel"".
Selecling common units in order to compare cmissions pc::rformancc kvel" rtrnongst options is onC ofthe two key issues thatmust he addressed 

### in a BACTanalysis. EPA's draft NSRManual states "it is generally most effective 10 express**~TIlissions** perfonnanoe as an average steady state emissions level per unit ofproduct produced orprocessed"'''

_ For fossil fuel-fired boilers, poond:; ofnitrogen oxides por unit offuel he"linput (i.e. 

### IbJrrmilltu), is a 

### COmmOn mCanS ofcumparing 

### ;md calculatingNOx emissions.
Many oontrol techniques, inclnding bolh add"on control" and inherently lowerpolluting processos can perfonn at a wide range aflevels. The EPA's**~ft** NSR Manual slales "It is nol the EPA's Intention 10 require "".lysis ofeach possible level ofefficiency for a contro!1echniqne, as**su~h** 

### an analysis would

" Ibid, NSR MallU'! D.18

" Ibid, NSRMOllU'! B. J8 "Ibid, NSR Ma"",,! B.25 17 Ibid, NSR Manual B.22
Doms & McDon:nell SquareBUlle Ele"trie CooperativeNO"BACfAnalysi' Srudy "Top-Down"NO"BACTAnalysi' Approach

result in a large numberofoplions"". Also, "manufacturer's data, engineering estimales, and lhe experience ofother S"urces provide the basis for determining achievable limits"".


### 2.4 STEP 4- EVALUATE THE MOST EFFECTIVE CONTROLS AND DOCUMENT RESULTS The fourth step ofa "top-d"wn" 

### BACTreviewis 10 eVJluale the technically-feasible emission controls, beginning wilh the most eITeetive_ Economic, energy, and environmental impaols are to be assessed and quuntified, where possible, in lhe control teelmology analysis_ The purpase ofthe evaluation is 

### to delerminc iflhere are any idenlified impacts thatwould eliminale lhe top controllechnology from c"nsiderntion_ 

### In the case where the most effective control alternative is determined to incur or produce adverse energy, economic 

### or environmental impacts, the basis ofthe determination is documenled, and the next most stringent control allerrmlivc is eVllluated_ This analysis proeess conlinues untillhe control technology under eonsideration carnlOl 

### be eliminated

### by idenlifioation ofany source-specilIe adver1;e energy, eeonomic or environmental impacts.

The eeonomic impacts are based on estimales ofeapilal equipmentpricing, procuremenl, inslallation and estimated operating and mainlenance costs. The total installed eapital cools along withthe operating COSts 

### for each controllechnology are summarized in the eeonomics ofcaeh respeetive section. 

### The Levelized Total Annual Cost (LTAC) represents the levelized cost**ofprocuremcn~** eonstroction, operation and maintenance overan assumed service life. Cost effectiveness (S/l"n) ofa eontroltechnique "r technology is calculuted by dividing the LTAC ($/yr) by the aruma! amount ofNO" removed (tons/yr). Baseline precontrol emissions are ealeulaled using realistic npper houndary operating assumptions, considering inherent physi<:al or operational constrainls on the source. Plotting ofthe annual amount ofNOXremoved (lons/yr) versus the levelized lolal annuul control eost ($/yr) for the various control options on 

### an )l-y graphallows l'isuab-zal'-on oflhe cost-effectiveness. A "lcast-cost envelope" can be readily identified 10 indieatethe inferior control options which should nol 

### be considered in lhe subsequenl analyscs_ The inoremental COSl-effectiveness (difference in 

### S/toJ;i) between eontrol techniques or technologies can also be oalculaled and compared This allows evaluation ofthe dominant controls indnded on the lea.st-cost envelope (curve).

" !bid, NSRManual B.23

,. Ibid, NSRManual B.24 Squam BUlle Electric Cooperative Burm & McDonneU**"Top.DO\,nnNO~** BACT Anal}";,; Approaclt


### 2.5 STEP 5 - SELECT BACT NOxBALTAmlysis**S\o~y**

The final step in lbe ·'top..<Jown" evaluationprocess is to seJeGlBACT for [he applicable poHutam ami emission ,miL Per the EPA guidanee document, BACT is "the most effeclive eonlrollechnology not eliminated in Step 

### 4"". The methodology described almve waS applied to the Millon 

### R Young Station Unil2', boilerfor emissions ofnitrogen oxides_



## *****

"Ibid, NSR Manual 8.53
R11ms & McDonnell SqlJllTI: ButteElectric Coo",,"'li'"NOxBACT Analysis Sludy BACTAnalysis for MRY Slalion Unil2 NOxEmissions


### 3.0 BACT ANALYSIS for 

### MRY STATION UNIT 2 NOx 

### EMISSIONS The approach lnkcn 

### in this BACT analysis for Milton R. Young Station included a technical analysis of demonstrated conlro] allematives forNOx emissions_ This approac"h followed thepredefined steps ofa BACT analysis process "s generally descnbed in Section 2. Potential No", control techniques and technologies were identified, and a technical description ofthe emission reduction process and capabilitie" Were provided_ Subsequenl]y, those techniques and technologies deemed available and feasible for retrofit application wcremnkcd according to nominal NO

### xcontrol capabillty. The engineering analysis lhcn developed the estimated capital and O&M costs for each alternative, including Inking" look at Bahmce ofPlanI(BOP) requirements. Finally, the cost effectiveness points for each feasible technology were plotled, and those thai comprise the dominant ""ntrols curve were identified.

For the feasible techniques 

### amI technologies considered 

### for determining 

### No", control cost-effectiveness for the two 

### steamelectric generating units atthe 

### MRY Station, estimates wereproduced forpredicted NOx reductions thairepresent "chievable long-tonn expect<ltions ofthe alternative reduction techniques and technologies being presentedinilie technic"l analysi". Each were tabulated and graphed_


### 3.0.1 EMISSION UNIT DESCRIPTION Milton 

### R. Young Unit 2 is 

### a Bubcockand Wilcox steam generator installed in 

### 1977_ Thc sleam generator is Ulignite-fired boiler withmultiple cyclone-furnaces installed in polI1lllel usingbalanced-drnft and natural circulalion assisted

### with circulation pumps. Originulllllit design steam generating capacity i" 3.20 million lbslhr at 2,620 psi witl1 a fuel heal input of4,696 

### mmHtuJhr_ The boiler is fired by twdve ten-fOOl diametercycloneburners, arranged "three over three" acroSS the front andrear wall" ofthe lower furnace. The unit has a tubular 

### "ir heater installedbetween theboilerand tho fiuo gus ductwork leading 

### to tho ESP. Exhaust gase" leave the airheater and pass lhrough anESP forparticulate collection andremoval followed by thetwo inducod draft fans (installed in parn.llel) prior to 

### awelilue 

### gas desulfurization (FGD) system which discharges 10the stack. The currenl airpoilulion control system's configuration allows a portion ofthe low dusl flue 

### gas to reheal the Slack gas, thus hypassing the FGD system. Unil2 has a nominal 439 

### MW net design output capacityrating, is capable ofsuslained outpul ofapproximately462 MW gross, and has an ultimate short-term maximum 

### gross outpul (URGE) of512 MW.

Square**Bu~e** Electric Cooperative 

### ;., Bums & McDonnellBACTAfUlly,i

.. forMRY Slolion Unil2 NO"Emis.'ions NOx BACTATIolysis Smdy

The EPA's Technical SupportDocumcnl22 lisL<; n"mcplalc slcam turbine-generalor capacity ofMRY Stalion Unit 

### 2 as 

### 477 MVl (gro",s), which was assumed for**cal~ula~ng** capital cost estimates for control allematives.

TheUnit 2 boiler at M.R. Young Station ineludes a unique coal conditioning syslcm (drying, crushing, and feeding) ror each cyelone furnace specifically designed 10 aid in proper combustion ofthe lignilc fuel. "Ibis melh",1 offiriug solid fuel signifJcanLly influences the re,ultmg nitrogen oxide concentration ofthe Hue gases emitted from lhe boilers.

Milton 

### R. Y",mg Smiion Uni1 

### 2'5 boiler design, combustion perfonnance, and NOx emissions are dominated by the composition und combn'lion characteristics oflheNorth DakOla hgnile supplied solely from a surface mine adjacent 

### to the plant This mine is 

### the only supplier ofsolid fuel for Ihis slaliou, as lhere arenO railroad facililies provided 

### to servicethe Millon R. Young plant. North Dakola lignite has high moisture and high sodium conlenl, moderale higher he:lling values, and can have a widelyvariable and high ash content compared to olher coals. These ch"mclcnstics**"r~';lle** difficulties inpromotiug consistent. 'lcHdy combustion and slag formation 

### in [he cyclone burners_ It also results in**produ~ing** a flyash lhal has severe deposition characloristics.

1be design unit operuting conditions forthis study are presented in Table 3-1. The historical average lignilc cool analysis is shown in Table 3-2_


### Table 3-1 - Unit Design Parameters lJnil2 Dosi n {lnit 0 oratiTI ChH,<led.,li<. nes] n BuilorTyp< SubcriliC'lII'l CumbUSlioTI System Cyclone Number ofCycIOllOS;**arraTIgemen~ lQca~Qn**  12; 3 OVor 3, opposed UnitDc,i n Co .cil Ekctric.l Dutcut"!, MW (TIell""oss) 439/477 (I) Balanced dran, SlOgiC drum. superhealed sleamw,th slOgle sroge ofsleam reheat. (2)

- ·These valu,,", W",e "'labli.hc<! by the original equipmeill IlLlmlrncnncers, prior to COllStruolioTI.

"'Ibid 

### Burns & McDonnell Square BnrreEleclric Cooperative.

### NO" BACT AnalYEis Study BACTAnalYElsforMRY Sla,ionUni, 2NO" Emissions



### 3.0.2 Table 3-2
- Historical Average Lignile Coal Analysis Lignite

- CenrerMine Average Ultimate CoalAnalvsis: (<IS 

### received) % 

### bv m<L<'



### Moisture 37.29 

### Carbon 38.69 

### Hydrogen 2.50 

### Nitrogen 0.57 

# '""" 0.81 

# "'" 8.74 

### Oxygen 11.40 

### To'" 100.00 

### HigherHealing Value, Btullb 6,661 

### NITROGEN OXIDES EMiSSiON FORMATION Nitrogen oxides (NO,.) are 

### produced whennitrogen in the fuel and combustion airarC exposed 10 

### high temperntures. There are 

### two primary sources ofNO" emissions., referred to as "themml" 

### No" and "fuel" NO"

.. Thermal NO" emissions are produced when elemenlal nitrogen in lhe combustion air is admitted 10 

### ahigh lcmpcroture zOne and oxidized. Fuel NO" emissions arc created during therapid oxidalion ofthe fuel containingnilrogen compounds. Formost coal-fIred units, thermal NO" emission typically represents appro"imately 20% and fuel NO" about 80% 

### ofthe total NO" formed_ Nitrogen oxide (NO) is typically the most prcdominnnl form ofNO" emissions fromfossil fuel combustion, along wilhnitrogeu dioxide (No,). The formatiou ofthcse compounds 

### in ulilily poweIplanlboil= 

### is sensitive 

### to lhemethod offiring and combustiou controls utilized. The techniques employed formixing the combustion air and fuel, which creates flames 

### and high tempernture combustiou products, results from the rapid oxidization of"arbon, hydrogen, and otherexothennic reactions. Cyclone-firedboilers, by design, create intense heal release mtes 

### to melland 

### fluidize !he coal ash introduced into thebarrel-sbaped furnaces. This produces high ternpernture flue gases and results

### in very high uncontrolled NO" emissions. The amount oftherrnal NOx 

### emissions produced by cyclone boilers can be considerably higherthan 

### fuel NOx

### emissions_


### 3.1 IDENTIFICATION OF NOx CONTROL OPTIONS FOR MILTON R. YOUNG STATION The 

### first step in the 

### BACf evaluation is to 

### identify aJl"'demon5lrated and potentially applicable control technology ahemativesn20 

### according to the EPA's draft NSRJ\.1anual. 

### ill identifying control technologies, "the applicantneeds to survey therange ofpolentially available control options'''''.

" Ibid, 

### [MlnOle numbcr 2, NSR Manual

### page 8.11 

### Square Bulle Electric Cooper'live BlJITl.< & 

### McDonnell

### BACTAnalysis 

### for MRY**S"'~OTI** 

### [hut 2 NOx EnlissioTIS NOx BACfATIoiysis Study



### 3.1.1 REVIEW OF RETROFIT INSTALLATiONS The BACT 

### delenninations listed in the EPA's 

### RACTIBACTILAEll ClearinghollSe (RBLe) 

### clnLabasc are 

### for new lacilities. Thc Millon R. Young Slation is an existing powerplant**[~ciliLy** 

### "Iilh two COJI-fired EGUs. 

### A BACT evaluation forretrofitting control equiprru:nllo coal-fired EGUs in an 

### exiSling facility will he suhslanlial1y**djrf~Tl.'n1** 

### limn an un"ly,is 

### forinstaIling control equipm,,"l On eoul-fired EGUs io a
new f"cility. Consequently, in perlorming lhe BACT analysis for existing boilers at Milton R. Young Stalion, it is imporlanl to review powcrplanl facilities, especially cyclone·fircd coal bOllcrs, which havc retrofiNedNOx control equipment in recentyear._



### In 1998, 

### EPA issued a NO

### x SIP (SLate Implcmentalion Plan) call. Under the SIP call, ulility boilers 

### in Ihe 

### easlern United**St~lcs** 

### were required to subatantially reduce NOx 

### emissions during the "ozone season". Thc compliance dale for lhe NOx 

### SIP call is May 31, 2004. 

### Ahighpercentage ofthe fired electric generalion facilities in Lhc**cast~-m** 

### Unilcd States Imve or 

### are in the process ofretrofitting NOx controls [0 

### comply 

### "lith lhc NO" SIP call. The £1'

### A's NOx SIP 

### call 

### was noL appliG"ble 10 

### North Dakota ulility boiler>_

Therc arc" number offossil fuel-fired JiGU**powerpl~nl.s** 

### "round the United Stales thathave implemented
or are planning to implement modifications Lo reduce NUx emisSJoos. 

### TheNOx emission control system inslallaLions are inresponse to Acid Rain requirements, EPA's NOx SIP call, lhe Clean AirInterSlate Rule (CAill), the RcgionJI Haze Rule (RJIR), 

### and local regulUlion8.



### In addilion to the facilities Lhal have 

### had 10 

### retrofit emissions controls as ure,lIlt oILhe Title IV 

### Parl 76 

### Acid Rain requiremenls and/or EPA's NOx 

### SIP call, a few installations have had 10 

### retrofitcontmls in recent year>; a8 lheresult ofcourt decisions resuiLing; from litigation and regulalory action_ None ofthe boilers associated with**id~"IItified** 

### consent decrees are cyclone-fired. They are 

### also located in a region requiring compliance wiLhan £1'

### A-approved State hnplemcnlationPlan for nitrogen oxides emissions controls (i_e. NO

### x SIP call). 

### As mentionc<l ubovc, North DakOla utility 

### boilers**w~7C** 

### not subject to lhe EPA's NO

### x SIP 

### call.

" Ibid, 

### NSR Manll.ipoge 

### n. il 

### Bllrn, &. 

### McDonnell Square BUlle Eloclno CooperJri"".NOx BACrAnalysis Study BACfAfioly,i. forMRY StalionUnit 2 NOx Emis.<iorn


## 3.1.2 POTENTIALLY FEASIBLE NOx CONTROL OPTIONS FOR MILTON R. YOUNG STATION A review ofavailable information onretrofit installations performed at utility andindustrial coal-fired powerphmls during the past fifteen years 

### was undertaken. NOx emission conll:oll.echnologies and technique.s with potenli"l applic"tion 

### 10 Millon 

### R. YOlmg Station boilers were identified, and are listed in Table 3-3.


### TABLE 3-3
- Potentially Available NOx Control Technologies Identified for BACT Analysis



## . " - 

## . NOx Control Technology
Pre-Combustion Controls Fuel CleoningIBlendinglSwilching Combustion Controls Basic Combustion Control Improvements LowNOx Burnm (LNB) Separa,ed Overfire Air (SOFA) Flue Ga, Recirculation Fuel Reburn Oxygen-enhaDced combustion (OEC) Walcr/"e3rninjection (combus,ion tempering) Post-Combustion Controls Selective Non.Catalytic Roducliou (SNCR) Selective C.talytic Reduction (SCR) Elcctro-Catalytic Oxidation (Eoo ) NoleS: Lhese are basic forms oflhe idenrified te<hni uc>. Not .1II'ari1ltion, orcombi,.tion, are included_ (1)

- SOFA l<chnologics iocludeBoosted SOFA and RoWing OpposedFi,ed Ai' (ROFA) (Z)

_ SNCll Lochnologi'" indOOe Rich**R~ent** lojoctloo. andHydroclDbon-enhanced SNCR, commoreio-lly avaJlableas ''NOXStOl,

_ (3)

_ Molo.pollolantcontrol tccJmology ourrrnl1y uOOorc"nunerda] development by Powerspon Co",.
A comprehensivelitel'lture searcb, 

### with sources including technicalpupcrs and presentations made at conferenc.es bynationally-recognizedteclmical organizations, utilities and othe' parties involved with design, coostruction, andtesting ofNO" control techniques, plus lrurdware supplierexperience lists, Was perfonned_ The results ofthis search are presented In Appendix 

### Al, which includes a sUJIlIIIlIryof various selcctcd U.S. No" cmissionrcduclion rctrofilprojecl'_
SqoaTe Bnlte EleCtric Coope"'tive 

### B\ImS & McDonnellBAd' Analy,i' It" MRY S!ariou Uuil 2 NOx Emi"inm



### 3.2 FEASIBILITY ANALYSIS NOx IlACT Molysi.**S~,dy Th~**  second siep oflhe**~top-.down"** BACTprocess is to eV"lllate the control proce... ,es lhat havc been ideLltifled and dclennine ifnny ofthe processe.' are tecbnical1y mfeasible.



### An avnilable tcchnolob'Y is "applicable" ifit can be**reason~bly** be**inst~lled** nnd operated on the Source type under consideralion. Also, Uconlrollechnique is considered available ifit**h~s** reached the st>lgc of licensing 

### and commercial availability_ For lhe purposes ofthis analysis, thc 

### term "commercia]" 

### is further defined lo mean "capable of,,--,tablishmg 

### afull conlrnclual agreement with comme,cJal and perfonnance " guarantees rupported by**nppropri~le** financial bad:;ng" for lhe imp1emenlation of**full--sc~le.** full-time systems ofthe technique or technology applicalion. 

### A technology !hal is avuilable and applicable is lCehnically fcasible.

There are three basie**e~legorics** ofNO" emission oontrol techniques and technologies:

• Pre-combuslion controls;

•**Combus~on** controls; .nd

• l'ost--combustion controls
Uneon!rollc(l NO"**~missions** from a coal-lire<! dCclrie generating unit are highly dependent On type of firing method, amount ofsolid fuel fired per unil time ffild furnace volume, and ihe fuel's h.sic combustion propelti"" and elemcnWI composition. The basic meilinds for reduclion ofsuch emissioru;:

• eitherprevenl pollulion, i.e. use inhe,enlly ]nwer·emitlm1;proccs>csJpraclices which proouce fewer NO" emissions during lhepower generation process; or

• involve improvements 10, Or provide new add'flll controls lhat, reduce emissions aJ1er lhey 

### arc produeed before lhey are emitted Irorn!he facility; 

### or

• are combinations ofinherently lower-emitting-processes and add-on comrols.

Most ofthe**iden~fied** conlrol opLions havc been commercially-available, installcd, lITId operating in many full_scale, permanent coal-fired utility boiler installations in the United St.tes for five years or more.

Pre--oombllstion controls, such as fUel switching, fuel blending, amI fud clc.ning have been prneticed and perfunned at numerous ntility powerp),mls, typically rur operational and sulfur emissions control reasonS.
Burn' & McDonnell SGuareBUlle EIc"ClJic Cooperative.

### NO" BAcr

### Analysis Study BACf

### Analysis forMRY Station Unit2 NOx Emissions

Combustion controls, such as low-NO" burners (LNBs) and overfire air systems, 

# = very commonly applied 10 reduce NOx emissions from fossil fuel-firedpowerplants. Low-NOxBumers are typically applied to pulverized coal, gaseous and liquid fuel-frred boilers. They arenot applicable to cyclonc-frred boilers. Flue 

### gas recirculation (FOR) has been practiced and perfonned atnUmerOUS nallrnll gas and fuel oil_fired utility and industrial powerplants for NO" emissions control reasons_ On 

### large coal·fired utility boilers, FGR has primarilybcen applied for steam temperature control purposes, not foremissions control. Conventional Gas Rebnm (CGR) wilh ovcrfire airhas been installed and placed in commercial operation on several cyclone-frred boilers, primarily in the c:ls(em region ofthe United Slates. Coal Reburn (CR) with oVcrfire airbas been suocessfully.demonstrated on two 

### cyclone-fired boilers and commercially installed on three pulverized coal-firedboilers in the United Sffite5. Combustion tempering (water/slcam injection) hasbeen tested but has notbeen continuouslypraclicccl on cyolone-fired coal hoilers_ Oxygen-enhanoed combustion has onlybeen demonstrated andJorinslalled On a limited number ofpulverized coal-firedpowerplants, not on any coal-fIred cycloneboilers.

Selective Catalytic Reduction (SCR) and Selective Non-Catalytic Reduction (SNCR) are post-oombustion technologies thathave been applied predominantly On eastern or midwestern bituminous coal-fired boilers. Others, mostly comprised ofa combination ofav"ilable emission reduction technologies, "'"

.. ol1.co referred to as "hybrid" or "layered" controls_ Variations ofSNCR., such as Rich Reagent Injection

(RID) with and without SNCR, have only beeninslaUed or demonstrated on a limited number ofcyclonefiredboilers. Other technologies, suoh as Fuel Lean Gas Rebumnl with SNCR, Irydrocurbon-enhanced SNCR (oommereially**avail~ble** (IS

### NOxSlarTM), aIld Conventional Gas Rebum with SNCRhave onlybeen demonstrated and/orinstalled On a limited number ofpulverized coal-fIred powerplants.
Emerging post-combustion mulli-pollularlIcontrol technologies, such as Pow""'J!an's Electro.-Catalytic Oxidation (ECa'"), whichineludcNO" control, were also identified. These are typica1Jy inthe large pilot-scalc commercial development phase, and have notbeen suocessfullydemonstrated on a full scale basis on anypulverized**co~l,** 

### cyclone, or circulating fluid bed boilers.

In most ofthe combination or "layered" and emerging oontrol cases, the NO" controltedmology has been demonstrated to be capable ofcontroUingthe targeted pollutant(s) on eitha;
• a fuJl-soale basis, but only with temporary equipment; or

• a full-scale basis, with pennanent equipmentbut in a limitcd number ofinstallations; or Square Burte Electric Cooperative Burns & 

### McDonnellDACT Aualysi, rOT MR.Y StaTion Unil2**NO~** Emissions NOxBAc:r Analysis Sludy

• with less than fulI·scale and full-lime applicntion.


### 3.2.1 SUMMARY OF RETROFIT INSTALLATIONS OF NOx 

### CONTROL TECHNOLOGIES**Th~'TC** 

# = a numher or facllilics around lhe counlry that have implemenled or**~re** planning to implement modifications lo reduce NUx emissions. Table 3-4**summ~rize5** lhe various NOx emission control "y5tem installations cWTently iUbl"Hed, orthat have been demonstrated on a fldl-seulc. short-term busis, in response to Aeid Rain requiremenlS, EPNs NOx SIP cull and local regulations, Or a utility investigating Ihe Il"Clmology_


### TABLE 

### 3-4 _Identified NOx Conlrol System Retrofits on Cyclone Coal-fired Boilers

1'\<>. ofUnits(I) C)'c1oDe NOx Conlrol T""hnology Des<dplion 

# , Foel Swirching/Blonding 

# '"' - - Separated Overfue Air (SOFA)


### ._. 

## . 

# - 

# , Selectivo Non-COI.lyric Reduction, wilh or wiilJout SOFA 

# " Rich**Il.e,genllnj~"Ction,** wilh SOFA 

# " - Convonlional fuel rebum (pulveri?ed or micronized coal, gas), wi SOFA 

# ,' . Fuel lean ga, rebmn, with Or with<lUt SOFA 

# " High-duST Or low_dusl SCR, wilh or without olhor leohnologies



# , , TaiJ.gas SCR, wilh or withonl oilier leohnologies 

# , , () TIll, 1,,1 ofknown NOx conlrol retrofil mstlllallons IS pnm8I11y fOCllSOd on nml' LIl II,. Uml<:<! SL""". There may be oLherinSiallalions lhOl "'" simil;orbul we", nor iden'ified. (2)

_ In,"'lIed ror**NO~** oonrrol (wiLhom ruel "bum). A l,sL orknown cyclone boiler SOFA insLallalions is indudeJ in AppendixA2, (J)
- RR1 has only bee" demon,tral<:<! wi'h tempOrOTy**<:qui~mom** fur Ie"ing. See teohnie,llilcr.uu", referonec:; iu Apl'eo,hx Al "d A2 for d,,,,ik (4)
- Sevcr.ll convenLion,1 coal and gas ,ebum relrofils h,ve disCOIItinned rebmn demon'I"'tiou or 'online opcr:Ulon. Se, Techn;cal Liter,tu", Ref",ence liS! amI Appendix A3 for furth'" details. (5)

- Only one CXllrnple offuel lean sas "bum reL",fi, (WiLhoul OFA) on a oyclone·fired oo,lerhas been de""'u,rraLed. This sy:stcrn was in,"'lled [or shon·lCm, ,ebnm "'"ling ,00 has been removed. (6)

- H'gh-<lu"**~CR** leohnology has heen '.-trofilled OU ,ixteen U.S. cydon<-JiH:d boilers, all helieved 10 have**~OF** A. Luw-<lu'l SCRs m U.S. hal'< only b<:cn inSl:lHed ooly un pulverized coal_rired ooiler>, uone on eyelo""" One 'ail_ gas SCR in,,,,llalion on a c:oal·fi"d cyclone boilerfonnd in Gennany; nuno in lh. U..s.**~ee** lechnieallileralurc "r«eno« in Awrndix A I ,"d**A~** [or d=;l,.
A more detailed description of,he VllriOU5 control "technology retrofits and their claimed effecliveness is inclndc<l in the t"dmical**descrip~ons** and reference lilcrature in Ihe lcchnical feosibilily**~ssessment** of

Burns &. McDonneU Sqnace Bullo Eleclric Coop=ti,'o.NOxBACT Analysi. Study BACT Analysis for MRY Sbtion Unitl NOx Emissions
Appendix 

### AI, amI Appendix 

### A2, which includes a summary ofvarious selected U.S. No", cmission reduction retrofilprojeots.


### 3.2.2 SUMMARY OF FEASIBLE NO

### x CONTROL TECHNOLOGIES FOR MRY STATION One example offuel switching applied to a cyclone-fired boiler was identified. Ottertail's Big Stone Unit 

### I was originally designed lo 

### bum North Dakota lignite andwas switched lo western subbituminous (PRE) Goal for reasons unrelated to NOx emissionsreduotion. Big Slone Unit I and M.R. Youug Station Unil2 have similar boiler deSigns. Thus, conversion ofMillon R. Young StationUnit 2 's boiler to fire PRB coal


### or a lignitelPRB blend is t""hniGallypossible. Thcre are no railroad facilities providedto service the Millon R. YoungplanL Additional operational and capItal costs to bring in large quantities ofPRB ooal will be significant. Based on a comparison ofavailable emission dam between OUertail's Big StoneUnil I and M.R. Station YOImg Unit 2, there is no expented reduntion 

### in baseline (i.e. unwmrolJed) No", ,_" omissions from switchingto PRE.from lignik atMillon R. Young Station. Although:fuel switching nt Milton R. Young Station is tenhnioally feasible, this alternative wiH not

### be cconomiGa1Jy**competiti~'e** with otherNO

### x nontroltechnologies thai oITerbetterresulls for 

### a munh lower combination ofcapital and operational costs. For these reasons, ithas notbeen considered further as an effective NO" emissions .control option for MRY Station Unit 2 boiler.
Sep=tcd Overfire Air(SOFA) is the most wmmonly-applied, nombustion-relatedNo", cmission reduction teclmology thathas been proven effective on cyclone-fired boilers, A version ofseparnted overfire air specifieally designed for increased NOx emission reductionpcrformarJ"" for lignite-fired cycloncboilers, referred to as "AdvannedSOFA" in this analYSis, canbe installed on both units atM.R. Young Stauon. The potential operationallimitations mentioned in the detailed feasibility discussions includedin Appendix 

### AI for deeply air-stnged cyclones associated 

### with separated overfire air are expecled [0 limit the control cifeotivcness ofthis teclmique, alone and in combination willi other feasible NOx control options.

SolectiveNon-Catalytic Reduction (SNCR) technology is a fOrm ofpost--combustionNO

### x emission control thalhas been successfully applied onnumerOUS utility boilersburning ea.'<tem bihIminous coal, midwestern bituminous coal, and, to a lesser e;xtenl, western subbitominous coal 10 reduce NOx emissions. SNCR

### has also bcen used on fuel oil and natural gas-fired units. SNCRdoes not appear to be dependent directly on the type ofbumers (wall-fired, langentially-fircd, and cydone-fired) employed in
SqUllre Butre Eleclrie Cooper.live Bums & McDormellBACT**An"ly,~,** lorMRY SmuonUuil2 NOx Emissions NOx BACTAnaly,i. Stndy

the**boil~'TS wh~rc**  it has been inslalled,**,,~lh** or wilhoul air_slaged combustion with overfire 

### air in full operalion_ This GonlrolleGhnology adds urea (orammonia) reagentto the hot furnaee gases in the upper furnace to chemically rcduce nilrogen oxjdes. SNCR W"S Gonsidered technically feasible for application On bolh umls at 

### M.ll. Yonng Stalion. SNCR can be operated wilh amI without SOFA. Vmulion. of SNCR technologies such**asHydrocarbon-enham:~d** SNeR (HE-SNCR) and "RolllInix" have been i"'I"lIed (ffi pulverized coal-fired boilers but are no! proVCll On cyclone boilers_ This is dc,;cribed in uclail in Appendix AI.

Rich Reagent Injeclion (RRI) is a fonn ofSNCR under developmenl specifiGally jnlo..'Ilded for NOx**r~** emissions conlrol on cyclone boilers. As ofOclober2006, RRI has been d<:mun,trnted bul has not been commercially installed and placed 

### in continuous opef'ltion On a cyclone-fired boiler, especially one burning coal with high fouling and slag lemperalurc sensitivilies associatedwith I ignite supplied from lhe Center mine_ 

### RRI o.dd, aqueous urea reagenllo 

### the hot fumace gases near the cyclones, which must he devoid offree oxygen in order lo avoid oxidalion oflhe ure<t which will increase NOx emissions. 

### RRI is**~onsidered** lechnically infeasible for application On lhe cyclone boilers al the Mllton 

### R. Young .slalion at lhe presenttime_ Thi, is described in dei<lil in Appendix AI.

Various [OnTIS offuel reburn with and without uverfrrc air are types ofcombustion-relaledteclmologies that ha"e been demon,trnled and commercially installed on I'ulverir-ed coal, fucl oil-fired, and cyclone utility and industrial boilers. N"ltIr.ll gas-Gonsuming v"rialions such as Convenlional Gas Rehum (CGR) and Fuel-Lean Ga, Reburn (FLGRn,,) have been applied 10 cyclone hoilers hurning bituminous and subbitumjnous couls. High capital costs expc"<:led for installing a natuml gas pipeline andhigh operating costs from consumplion oflarge volumes oflmch fuel**m~ke** these alternatives economieullyunfavornble for both unils al M.R. Young Stalion. Pulverized ormicronized coal rebum, in combination with SOFA,
are technically feasible but will require cXlCnsive capilal, operaling and mainlenance oosts for fud grinding equipment and facililies when installed and GpCIilled for both units al M.R. Young Stalion. This is described in delail in**App~'Ildix** AI.

Fuel cleaning is a lechnique nOlmally applied lorcuuce lhe sulfur or ash conlenl ofa fossil fucl prior 

### to eomb\lstion. No examples offuel cleaning ofNorthDakola lignite 

### or weslern subbituminous coal striclly for NO" emissions reduction**w~'TC** found in available lechnicalliterature_ This technique 

### i., Gonsidered infeasible JorNOx emissions control of

### M.R. Young Stalion boilers at Ihc pn:seal lime.

Bums & McDonnell 3_10 Square Ilulle Ekctric**Coop=~ve. NO~**  BA.CTT Analysis Study BAcrAnalysis forMRY Station Uoil2**NO~** Emis.sions**High-dus~** low-dusl, und tail-gas variations of""loctivc call1lytic ",duclicn (SCR) technologyhave 

### been applied on pulverized coal and cyclone boilers as apost-combustion type ofNOx cmission control throughoutilie world and 

### in !he UUilCd Stales, except on unils 

### .frringNorili Dakotalignile. 'Ibe severity ofcalalysl blinding andpluggage from particulatematter and flue gases emitted from cyclone-frred boilers burningNorthDakota ligniteprecludes the tedmical feasibility for successful application ofsuch SCR lochnology on lhe EGUs at the Milton 

### R. Young Sllltion. 11Ii5 is doscribe<l 

### in detail 

### in Appendix Al with supporting docwnenllllion in Appendix B.



### The rcsulls ofStep 

### 2 ofthe 

### NOx BACT Analysis 

### for detennining the technical 

### fC<lSlbility ofpolenlial control t«:hm'logies, including various ·'Iayered" oombination5, are listed inTables 3-5 and 3-6.


### TABLE 

## 3·5 - Technically-Feasible Potential NO)( Control Technologies for M.R. Young Station Unit 2 Cyclone Boiler

In**Perm.aQen~** Full·

SC31e S.nic. Dn Exining Ca31_Fired Cyclan. Utillty Technically 

### F

...,ible on M.R. Young Control T.chnolo 

# '" Boilers? Stallon Unil2 boiler? Selective**Nou-Ca~lytic** Reduction (SNCR) Yes

### m 

### Yo uiresSOFAorASOFA " Conventionol Gas Rebum YesQ! 

### Yo CoaiRebum Yes' 

### Yo> ; R nile, SOFA orASOFA Fuel Leon Gas Rcburn 

### N" Y" (wIor W/OUl**SOF~SOFA)** Advanced SOFA No' , 

### Yo>

. Inc1ud<:s relocaled' ',e dryin vcnt om So anted OFA sicSOFA Yes' ) 

### Yo> Combustion 1m roVcmOulS 

### Yo> Yo>
" icall included with se orated OFA flue Gas Reeirculatiou No, forNOx cOOlIol 

### Yo> uote ..,lcd to rcduce NO" further) Fucl Switehing 

### I Blcndin 

### y" 

### Yo> (nol e ..,lcd 10reduce NOx further)



## .. S

.. tecllIlleal feJlSJb,hty demil, and hterillIIrc Rcr.:rrnccs In Append,. A for del.a1ls. (1)

- All pnlrnb',l ,0rnblOOlion, nfI,chnologi", no' li...,d, Bee di><n",ion of"J.yer<d" Lsemologies. (2)- A.sSllmes use Dfureaf<rr reagrnl. LintilOd IlIr1tl1>cr of'c[ivc instlliations on cydou'-fired bailen; burn;ns wesLern subblluntin01lS (i.e. PowderRiver &s;u DrPRB) ""aI. (3)

_ LintilOd nlODbor ofactive oonventional gas rebum (COR) insWlations on cyclone-fired boilers burning PRB coal. (4)

- Lintired number ofdcmouslf3tious 0' aclive iM,U"l":" ofpulverized ormicroni=l 00.1 "burn on cyclone-fired boile". One dcrnonslnolion ofpulveri7.<'li coal rebnminswilh PRB cool has b= pc:rfonned on 0 cyclon,.liT,dhoiler. nD longer oc[ive, Ocly ono '<li>epcrmenen' coal rebum inslOllalion on cyclone-firedboilerbumil18 e"I'm bilUminou, 00.1, nOne b"mjns PRB cool or ligoit<. (5)

- Ocly one ""OIl_Ls"" ,,," demonslraJiou ofFLGRTH on aeyclone.f!IOd hoij" buroing cool with s"p""l<:d ov<rfire air, (6)

- No cyclono bo;lers firing North Ds.ko

.. Hgnltc h.ve ie,Wlled basjc Ot" odvanced SOFA. Be< Appendl" A. (7)

- Con,idered p:ut ofSOFA installation fOt" ""alhollers wilhoul oombu,tiou ooo[rois fDr NO. rednetion. (g"j

_No ""ample, ofusing reciroula1ed flue gas on coal-fired boilers forNOx emission, ,oulrol

# w,,,, found in o""jl.ble "choi,oll;tcnllUre. Zero .ddiliocaJ No,. n:dcetion pnLential c;pc"ed from [his 'echnlqIIe alone for MRY StationUn;l 2. POLential NO. reduction improvcmo:nt oU MRY Unill considered p:ut oC"advanced" BOFA. (9)

- Zero .Mitioaal NOx reduction poLsntial e.pecl<d lium lhi, t,cbllique ("",i[ehing from Hgnile 10 Iignilell'Rll blend, or IOO%PRB) sloue fo, MRY SI'lion UUlI2,
Square**Bn~c** Electric Cooporati>e 3-11 Burns & MeDonneUBACT Analysis for MllY Station Unil2 NUx Emi"ion,**~Ox** BACT An.ly,is SluJy



### TABLE 3-6
- Technically Infeasible Potential NOx Control Technologies for M.R. Young Station Unit 2 Cyclone Boiler

- 

# ... 

# .

o " (I)

_ All pQLeIltiol combina,ion, of",chnologies nollistod. See di,ou",iou o["layered" lechnologies. (2)

_ LimiLod numher of"",ive in,",ll.ti"", oa oyclone-fired bOller, burning wesLern ,ubbiruminollS root (3)

- No i,leIl'ifiod io,I.H"io05 on ooal·fiTCd ooil.,. io ti,e Un;Led**~"tate,.** One Lail_end SCR00 'yolonc boil", iu Gormany. (4)

- See discossioa orSeRfcosibiliry rOT NO lisnite io Appen<l" Al "IIU ApP"ndix B. (5)

_ Ilyd<oca,bon""uhancod SNCRb

.. not bc"" dcrnonstrat<d on 0cyclQno-firedboiler, uor any boilerfiring Wc,lcm ,ubbiluminou, 0001 or!,gmLo. (6)

- Rota'iug Opposed_FIredAir with orwilhouI SNCRba, nol beeu demonsn-a'cd on acyclon.·fired boile,. No "pp,rcnl significanl odvon"'ge, nve, SOFA on cydouc.rm:d boil"". (1)
- Ricll**R~gc:nllTIjo<'i""** bas been SIlccessfully demon""'''''' [orhrier""rioo' wllh SOFA wilb Olld wilbou' SNCR al Iwo ")I<lon, powerplOllLs. ·Ih,re are no perman'ul RRJ m,l.n,lion, oompktoo and opcnrional as ofMay 200fi. Oiilioulrics in m,mtoioing "" o,ygon-frcc furrnlcC environmeIl' in MRY SIaIi"" boil,,,, wl1<re lhe ureaT"'I.:oul woold bo injacled duo 10 oy<:lono .irlfud imb,lancos during air_slarVed oombo,1ion woold in=,c NOx <missions. (8)

_ No kn""n demo",,,,,,iou, or pe'ma"eol in'I,Il.tio", o[Advauced ""uveuLionaf gas r.tum (CGR) or FLGR'" or pulv<ri?erllmicrolli,-od c('I,1 rc:b"", (PCRhnCR) ill combiooLion wiLh sNCR ou**e)'Clouo-firc~** boile,.. CGR and PCRlmCR IT'Juirc ,,,!,,,al,d ",,,rfiro air. FLGR'" ilas boon**,pplic~** 10pulV<rizoo coal firing wilb

...dwiLhoUL SOFA, wilh ""d wiL/Ullfl SNCR; FU)R"" "mh SNCR JS 01'0 callod ""ino_enhanced fuel lean g"S rcbum (AEHAJR"'). (9)

- No known uOIIIon'I"'lioo, orpermanenl in'I,U'lion" ofO'ygOlXnbilIlOro oombustion (OEC) on oydoue_","" boil"",. (10)

- No pemlOTleTlLly iustlilled ""ample< oru,iug this '«hniquo eon'inuomly On ""ai_fired boiler> =0**rO"n~** in availahle Leclmkal lit""'01re. NOI ,oil.blc [orhigh_moisture lis"i'e rueIs. (11)

- No know" <I'mo".'''''lion, orpern"",onl illSl,lIaliou' ofu'ing lhi, teo<:hniquc conLmuously on eool_fi,od iloiler> [orNOx cmi""ions control wcre found m aVallablo leclmkallllcrature. Tn Pormancnl, FullSc.le Sorvice on Existillg Coal_Fired Cyolone ()'illiy 1'erbnioally**~'e",ible** 00 M.R. Young COlllr,,1 Tcchnolo 

## 0') Boilers? Slaliull IJnit 2 boiler? Seloctivc Calalylic Rcduction No'"

- Unresolvable fouiing and ",,"'lyst (SCR): convenlional (higil**deaclivation.~~~efms** c;o;pcclcd- See disClIssion du,I);**Lnw"du,~** Tail-gas Yes[2) / No I y.,' 1 ) ofSeR ftllSlbilil fnr ND hgmlc. Elcctrn-f".alalytio Oxidalion No, has nol been demnnstralod full-scale nor (ECO"') N, ","chod commercial availability HE-SNCR (mm ammonia) No' , No' '. Hll'l nOl been demon,tralod 00 cyclone. Rolamix ROFA+SNCR) No'" NoW Has nol b<=l domon,trolod 00 cyclone. Ricb Reagent lnjcctioo (RR))**N~~:~~~qUire,** o"}1;on.[Tcc Jilrnaco Cllvirorunent, w;lbASOFA No('1 var in air/fuel would incrcasc NOx emissioIlS. RRI + SNCR willi ASOFA No' , No' '. See [ooluole .aJ fcaSlbilily disoussion.**Advann"';~** Conventional Gas Reburn ACOR) + SNCR Nol') No. Ilas nol been uemonstrated 00 cyclone. Coal Rclrum + SNCR No"! 

# " Has nol bem dClllomITaLed on cyclone. Fuel LeaTI Gas Rohum+ SNCR Nol" N,. Has TIQtbom dClllOTIstrated on**C}'C1on~.** Rom 0 osed Fired Air N,' N,. Has notbeen demOilSlraled on c cione. OxygenEnh.noed Combustion No(' No. Has notho"" demonstraled on c donc. Warer lnjecIioll No('" No' Fuel Cleauin Nol rOTNOx control N,' (nol ex or€<! (0 ",duce NO,,- furlher Soo toclmicfll feasibll[ delail, anu lil=lure Refe",uo" iu A ,ndi, A ror del>1Is.

Burns &**McDonn~U** 3_12 Sqt,are BUlle Electric Coop=tive_NOxBACT Analysis Study BAct'Analysis fu,-MRY StationUnh2 NOxEmissions

Additional criteria besides technical feasibility are lItili7...ed fo,- technology selecllon in "-BACT analysis have

### been included in the following sections summarizing conlrol effectiveness estimates, ""pital plus operating and maintenance cost eslimates, ene,-gyimpacts, ami environmenIal impacts:

• Control effectiveness (i.e. percentpolllltantremoved)

• Expecloo emissionT1lLe (see Tables 3-7, 3-8) and emission redUClion (tons pe,- year)

• Economic impaels (Ictal cost and incremental costeffectiveness)

• Energy**impa~ls**

• Environmental impacts (olln.-'[ mcdia and emissions oftoxic and hazardous airpollutanls)


### 3.3 RANK OF TECHNICALLY FEASIBLE NO

### x CONTROL OPTIONS BY EFFECTIVENESS The third slep in the '"top-down" BACTevaIuationis to rank thcremaining control tcclmologies by effectivencss_ The pmpose ofrnnking the controlleclmologics is to eSlablish a hierarchy that "places al the '1op" the eontrol technology that achieves the lowestemis>;ion level."

. TIle'emission reduction (control effectiveness) percentages developed forranking the**~vailable** 

### NO" emission control options considered feasible forMilton 

### R. Young Station Unil2 are shown in Table 3-7. "', 

## , The.., are estimales hased upon engineeringjudgments with considerations 

### 0[:

-. Boiler heal inputrales associated 

### with realislic upper boundary operating assumplions;

• baseline emission rales correspondingto the realistic upperboundaryoperating assumptions;

• the general combustion properties of

### North Dakota lignite;

• published and available emission reduction perfOlmance achieved at other similar utility powerplants (cyclone-fired boilers);

• compute,--derived predictions; and

• inclusion ofperformance margins to allow for varialions in 

### fuel, weather, equipment condition, and other factors that prevenl lhe ultimate peakshort-termperformance from being reliably sustained over the course oflong-termoPCT1Ilion.

These 

### NOx emission level and reduction percentage eslimales include adjustments ofpreviously demonstrated orprcdictedperfonnance lhatrefiect diJIerencesbetween North Dakota lignile and eastern Ormidweslern bituminous andwestem subbituminous coals.

Square Bune Elecltic Cooperative 3_13 Burns & McDonnellBAcrAnalysis for MRY Slation Unil2 NOx**Emi~,ious** NOx BACTArully.is Sludy

The numbers assume lhe estimaled capability ofthe employed Lechnique is achievable and sustainable (long-term) and that polential operalional limilalions menlioned in the feasibility discussions allow lhe succe3Sful praclice oflhu teclmique or teclmology. None oflhe remaining control OptiOIlS has been installe<i on a cyclone-1ire.:] boiler burning N0I1h Dakot.a ligniLe. At; such, the expressed control percentages refJcollhe USe ofengineeringjudgment,**b~,cd** on lhe Iis!ed tedmique or technology applicalion. "fhis is partienlarly pertinent to an eonlrol options Lh"l involve "ir-staged combustion associaled wilh vmous forms ofseparajed overfire air. SOFA-based controls for cyclone-fired coal_ burning boilers h"ve typically reduccd NO

### x emissiollievels signifjoanLly from the precontrol b""e1ine, JIld which allow or enhanec furthcrreduclions when combined wilh other oontrol techniques und teohnologies_


### 3,3.1 ESTABLISHING BASELINE NO

### x EMISSIONS FOR RANKING CONTROL OPTIONS Beforc Lhe various feasible NOx emis,ion control alternatives eun 

### be eSlimaled and rant:ed in**ord~'T** of effectiveness, the precontrol baseline level ofemissions am) its basis must be delennine<.1. The EPA's NSRManuul provides general guidsnce for cslablishing estimaled baseline emissions to be used for Lhe pmpose ofcalculating and comparing the conlrol and cost_effecliveness ofa control option: "The baseline emissions rate repre.lenls a realistic scenario ofupper boundary uncontrolled cnnssions from the source. The NSPSfNESllAP reqnirements Or Lhe application ofcontrols, including other con(rols necessary to comply wilh Siale or local mr pollution regulalions, are not considered in calculaling lhe bsseline**~'IIlissions.** 

### In olher words, baseline emissions are essCIllialIy llncontrolled emi ssions, calculated using reali,tic upperbournJary operaling**assunlp~ons_** When ealeuJuting the CO.lt effecliveness ufadded post-proce" emissions control, to certain inherently lower pollmingprocesses, baseline emissions may be assumed 10 be the emissions from the lowerpoiluling process itself In other words,**~"TIlission** reduction credit Can be taken for the use ofinherently lower polluling**prooesses'~5.**
Also stated in lhe EPA's N.'lR Manual: "Kllimaling rcslis!ie upper bound case scenurio clocs nol mean lbat the SOUrCe operales in an ab,;olule worst-case manner allihe lime. For example, in devcloping a realistic upper boundary case, baseline emissions calculations can also consider inherent physical 

### or operational constraints on the source. Such eonstrdints should aceura1cly reflect tbe true
"Ibid, NSR Manual B.37 

### B\Il'IlS & McDoIlIlell 

# '" SqUaTO ButleElecnic Coopernliw.NOx 

### BAerAruJlysi, Study BACTAnalysis for MRY Station Unit2 NOxEmissions

upper boundary ofthe soun;e's ability to physically operate and the applicant should submit docUmentation

### to verify these constrainls·"·.
Eslablishing estimatedbaseline 

### NO

### xemissions for a new or existing source involves determining the design or operational basis ofthe emission rale. 

### Auseful means ofcomparing such emissionrales is [0 establish the unit emission rate, expressed inpounds ofponutant per unil ofprocess output. Forprocesses such as slearn-electric generating p<Jwerp]lIIlts utilizing combustion inboilers, lhe desired process output (kilowatts or megawalts) can be reluted to thepollulant-bearing flue gas crealedby lhe combustion of fuel. Unil>: offuel heat inpul (millions ofBWs) required 10 create a unit ofdesired electrical outpul 

### (leW) and tlms the efficiency ofconverting the fuel heat to sueh clcctrlcal output (unitheat

### rote, BtulkW-hr) are important



### A review ofreported hourly NOx emissions forMRY Slalion Unit2 boiler, including unit mass rates (IbhnmBlu and lblhr), hoilerheat input (nnnBtu/hr), and gross electrical outputinmegawatts 

### (MWJ, 

### was performed for the OpCrlltingperiods in years 200! -2005 inclusive. 

### A realistic upperbound emission case

.scenario for each boiler's baseline emissions atMilton 

### R. YOImg Station detennined the highest summation ofanyroHing 12-monlhperiod No" mass emissions (pounds), along with the summation of ll1e gross heat input 

### (mmRtus) and the boiler operatinghours forthe same rolling 12-monlh.period corresponding 10 the highestNOxpounds, Dividing the summation ofthe rolling 12-monthNO", pounds hy heat input results in a average unit emission rales (Ib/rnmBtu). Likewise, lhe summation ofthe rolling 12-momh 

### gross heat input (mrnBtus) divided by the boiler operalinghours yields 

### an avr:rage gross heat inpulrate (mmBtu/lnl This emission evaluation revealed thal:

• Unit 2 al Milton 

### R. Young Station is typically operated 

### in a base_loaded manner;

• :MRYS Unil2's highest 12-consecutivemonthNOx mllSs emissions summation divided bythe surnnmlion ofthe same 12-month period's heat inpul aVeraged 0, 7861b/rnmBtuata corresponding average unitheal inputrate of4,885 rnmBtulhr andunit gross electrical outpul of 

### 440MW•.


### 3.3.2 ESTIMATING CONTROL·EFFECTIVENESS OF NO

### x EMISSIONS CONTROL OPTIONS The degree ofsucccss in operalionofscparalCd overfire air alone andin combination 

### with lhe other selected feasible alternatives is important to 

### the arnmml ofNOx emission reduction achieved. The
"Ibid, NSR Manual B.37 Square Butto Electric Cooperalive 3-15 Bnms & McDonnellBACT Aoaly,i, for MRY SmlioJl Unil2 NOx EnllSsiQllS NOxDACTAnalysis Srucly

emiSSIOn control perfonnanee from lhe advanoed version ofsC{Xlnlled ovcrfire air (ASOFA) is highly dependent on lhe degree ofsuccess in**~<lmil1ing** combustion air insufJIcicnt for oomplete combustion 

### in the cyclones wilhout causingrelated negnlivc in,pacls. The control**pel'c~nlagc,** cslimated for frring 

### North Dakol£llignile in the MRY Smlion boilers**ref]~c1** tbebchcfthat operaling lhe exisling cyelones much below an average cyclone sloichiometric nHio ofapproximately 

### 0.95 (95% oflhe lheoretical amount of oombuslion**~iT** required for complclc oomlmftlion) will not be successfuL This is ,lucprimanly Lo lhe expected ·'starved air" combuslion causing. reduclion in cyclonc**fumac~** gas**lemperaturc~.** thus c,calmg
a strong potential for molten slag solidifying in the cyclone barrcls, slag laps, and lower furnace floor openinr;s. This wouldimposc a great intermption Lo sleam production since forced outages would be**i':~-** required to remove this physical obstruction before full load**boil~T** operalion conldbe reeslllblished. The EPA's draf! NSR Manual states 

### "II is not the EPA's inlention 10Tequire analysis ofeach possihle level of e1T!ciency for a controllechnique, as such an analy,is would result in a large number ofoptions"".

The potenti.l opcrationallimiLarions for deeply air-.'laged cyclones aseociated wilh separaled overfire air and coalrebum allematives are expected to limillhc amount ofNOx control pOlential possihle from successful practioe oflhe particular leohnilluc or technology. This is**dc"~Tibed** in the dctaik-d feasibility discussions included in AppeJldlX 

### AI.

The advanced form ofscp=ted overlJrc air is expected 10 be effcctive inNO

### x emissionreduction aud Can bo combined wilh olher f""sible combustion-relaled and post-combusrion control alternatives 

### for Iho", lignile-fired cyclone boilCTS_ The ba.,io fonn ofSOFA in oombillation wilh coal rebum,**~s** rebum options, and SNCR, was not ineluded in lhc detailed controi effeclivencss analysis ill**ord~T** 10 limit lhe number ofoptions that were evaluated.
Using 

### an advanced formofSOJo-A system, M.R. YOlmg Sialion's Unit2'" boiler operating atMCR 

### is cxpcclcdlo achieve a NOx emission level of

### 0-49 ib!mrnBtu when operaling modestly air_stagcd cyclone furnaces with suitable oombUSlion controls_ This lcvel ofNOx reduclion fromASOFA operation, approximately lhirty eighl percent, is based on Ihe expected abilily 10 reduce emissions wilhout incurring polenlial significantnegative impacLs ofthis lechnique_ This reduclion cslimale includes !he addition.l .mounts ofcontrol potenlial available from operaling willi relocaled lignite drying syskm vent ports (and }'GR ports for Unit 2) associaled wilh ASOFA operalion with modestly air-sLagcd cyclone fumaoes_

"Ibid, NSRManual B.37
Rums & MtDmmdl 3_16**S~uare** Butte Electric C""pcTIllive.NO" BACT Analysis Srudy BACT Analysis for MRY SlationUnit2 NOxErnissioIlS**Co~l** reburn with ASOF

### A 

### is estimaled to reduce NOx emissions for 

### M.R. Young Station's Unit 2's !>oiler operating atMCR slightlymore than 

### 54percent nOmthe pre-control baseline NOx emissionrnte, considering similar control levels demonslrnlcd by previous cool-reburn retrofils On cyclone-fired boilers and limilations previouslydiscussed wilb ASOFA.

Conventional Gas Rebum and Fuel Lean Gas Rebum options werebolh assumed 

### to be installed wilh ASOFA. NO" rednction from COR with ASOFA operation is expected 

### to be approximately 

### 55.4 percent. FLOR wilhASOFA is expecLcd 10 reduce NOx emissions appro"iJllillely forty**fi~e** percent. Eslimales for NO" emissiollS for 

### MR Young SllItion's Unit 2's boiler considered similarcontrol levels demonstrated by previous gas-rebumretrofils on cyclone"fired boilers Wilh modestly air-slaged cyclone furnaoes and limitationspreviously diSmISsedwith ASOI'A.

TheNOx emissionmle for SelectiveNon-Catalylic Reduction (SNCR) (using urea) with ASOFA is expecledto be**~pproxiIlliltely** 

### 0.355 / 0.33, resulting from a reduction in NO" emissions ofapproximately 

### 5S percent from the 12-month avernge pre-<oontrol baseline NOx emissionmte.

Included in the fcasiblecontrol option 

### ranking ofTable 3_7 

### are layered alternatives that 

### were shown in Table 

### 3-5_ The highesl-performingNO" control allemalivcs remaining in consideration are rnnked 

### in .declining order ofexpected emission reduction. These combined control 

### oplioru; refer to "adv:mccd" SOFA, which is cxpccte<:l to have significanlly 10werNOx emissions than a typical SOFA systemas applied to the Millon 

### R Young cyclone boilers.

SquareBune Elecuic Cooper-Hivc )-17 Bums & MoDonneliBAcrAnal}";, [o,/>,fRY Slalioo Unit 2**NO~ F~nis,iollS**  NOx BACT /In.,!}'si,**SI~<.1y**



### TABLE 3-7 - Ranked NOx Control Options Feasibla for MRY Station Unit 2 Boiler with Expected Control Performance

( ) gnatJ gn (2) • Control perce"!2ges aco ,,],live 10 an av'rnge pre-control emi"lOnboscline ofO.78G**IMmn~L~** 

## "">Cd on**ann~al** o""r.lioo or h;ghe,! pr<o--<;ooiroi 12·monLhrolling NO' "'romal;on01= em;"io", divJded oy**L~e** l2-01onlh heaL inpu' so""n.tion.**~,.** Emi'sion**~,~c** Conlrol Labell') NUx CanlTol Tcchoi 

# "' (lblmmBlu Pereenla 

# ." 

# , SNCR(usingurea) 

### wIASOF/I 0.330 58.0



## .. -'. - ._-,,'- D 

### c",-, Raburn wilhASOFA 0.350 55,4



## .. C LiguiLeRobum 

### wI ASOFA 0.360 54_2



## . 

# , Fuel Lean Gas Reborn wiiJl ASOFA 0,432 45.0

. - A Advanoed Sep0raled OYecfuc Air (/ISOFA) 0,489 37.7

. Baseline 0.786 

# , _AII='livede>i onassi ed room high"'L 10 low""luniL NOx emi,"on "'e.

The annual**~,nission** levels developed fOT Table 3-7's ranking the feasible aliernatives ""mille thol the highest 12-month average pre-retrofit level ofunil NO

### x emissions fOT M.R. Young SLatlOn's Unit 2's**"_""'r~** 

## , .. boiler is a baseline of

### 0.786 Ib/mrnBtu. This W"S detelmined from the highestTe]lorted rolling 12 conseculivc rnonlh period's summalion ofhourly NOx emis,jons (lbs).

The hourly gmss fuel heat input (mrnBlu) was summed over Ihat wme 12-month lime period, and divided by Ihe numlJ<,r ofboiler operating hours to yield an annual average gross fud heat inpnt rate (mmlltnlhrl_ Multiplying 'he 12-monih aven,!,,,, heat input rale (mrnBlu!lrr) by the baseline oreoncrol alternative's 12- monlh**aV~TJge** unit emission rale (lb/mmBlU) equals a 12-month average hourly NO" emissions rale (lbilrr). Annual NO" emissions (tons) fOl" Ihe baseline pre--control condition WeTe calculated by multiplying the 12-monlh summation fOT boiler operating homs during**~Ie** same period as Ihe highesL NOx**~missions** by the 12-month average emission rate (Iblhrl. The annual tons for Ihe conlrol options
were calculated by mnlliplying the**~lIcrnalive's** average anmml emission rate (1b/yJ") by u reduction faetOI" (ifapplicable) forheal inpul OTrunning plant enpacily and adjn.ting boiler opcrnlinghoun; by an urmual l,plirnc (availability) factor. Del:lils for Ihese adjusiments 

### a«: included in Appendix 

### 0. B"sed on these c"lcuJations, the annual emissions fOl" M.R_ Young Station's UnilZ's boilerare sho"l11 in 'fable 3-8.

Bums & McDonnell Square Bune Eleclric Co<lper:uh'e.

# , j
• 

# i 

# , , £ 

# J g 

# • 1 

# J

, 

# , 

# ,NO" BAcrAnalysis Sltldy BAcrAnalysis [orMRY Station Unil2 NOx EmissiollS



# -----------------
3.4 NOx CONTROLS ANALYSIS AND IMPACTS EVALUATION The fourth step ofa ''1op-<!own'' BACT review is to """Juate the most effective cmission controls. Energy, economic, and environmental impacts are to be coru;idcred inthe control technology evaluation. The purpose ofthe evaluation is to determine jrthere are any energy, economic or CIlvimnmenlal impacts l1111t would eli

### minale the top conlrol technologies from consideralion.


### 3.4.1 NOx CONTROL ECONOMIC IMPACTS FOR MRY STATION UNIT 2 An evaluation wasperfonncd 10 detenninc lhc various cost impacts ofinstalling feasible NO

### x oonlroJ alLcmatives on Mihon R. Young Unil 2. This evaluation includes estimated:

• Capitaloosls;

• Fixed and variable operating and maintenance cosLs; Bnd

• Levelized toW annual costs to engineer, procure, conslruct, install, sloItup, lesl, and place into commercial op""'tionthe particular controllcchnology. The resulLs ofthis evaluation aIe summarized 

### in Tables 3-9 through 3-13.



### 3.4.1.1 CAPITAL COST ESTIMATES FOR NOx CONTROL ALTERNATIVES The capital costs to implemcmthe various NO

### x control technologies were largely estimated from unit output capital cost factors (SIkW) published in technical papers discussing those control technologies. 

### In the caSeS ofSNCR, preliminary vendor budgetary costinformation' was obtained andused inplace of, or to adjust, the publishcd unit output COgt factors. These cost estimates were considered to be 5tudy grade, whichis 

### + or -30% accmacy.

The unit rnImcplale output capacity (gross electrical output 

### in megawatts) assumcd for the NOx control technologies capital costestimatc basis was 

### 477:MW, for 

### MRY Station Unit

## 1"'.

A review ofthe unil capital cost factor l<lnge and single point factors applicable to 

### MRY StationUnit

### 2 NOx control technologies arepresented 

### in Table 3-9. The estimated installed and levelized capital costs for thc highest-performing form ofthe various feasible NOx emissionreduction technologies evaluated for cost-effectiveness are showlI in Table 3.10. These arelisted in orderofcoutrol effectiveness, with the highest ranked option at the top.

20 Ibid fooUlole IDImber23. Square Bulle Elecrric Cooperalive 3·20 Burns & MoDonn.llBACT Analysis for MRY Slalion Unit2 NOx Emi.sion,**NO~** BACT Analysi, Study


### TABLE 3-9
- Unit Capital Cost Factors of Feasible NOx Control Options for MRY Station Unit 2 Slogle Point Unit Capital Cost I1adorPJ, 

# "". R.ngell) (SlkW) Label"] NOx Conlrol Techni 

# "' 

# ,""W) MRYS Unill 

# , SNCR (usiug urea) 

### wi ASOFA 20_35)6) 35.9(').1') 

### _.0. D 

### Gas Rebmn 

### wIASOFA 15_JO(O) 74.4(5).1').(1) C Liguile Rebum

### wi ASOFA 30_60(')**j70.2~W)**



# ---- B Fuol Loan G

.. Rebum 

### wi ASOFA ••(OJ 45_-r'M5),M



## . A Advanced Separal<:d Ovcrlim Air (ASOFA) 5_10(') II (') (I) A11crnahvo dCSlgnahou has been ass'gJled ffUm h,gh",,' 1o 10w",I\lmlNO. <JIIl'Slon rat<. (2)

- UniL capilol oosL factors (S/kW) ofIhese iul!ividu,llecimologi" oombincd by simple oddilio". Aclillli in'l.n,d co.lI, m,y differ Lhis due 10po,;';,'e or n<g,'iv, symrgi,lic**effw~** Range ba>ed on publi,hed vaJ"" or vondOTproposals. (3)

- Single poiol '-0'1 f",lor is b"" ",rimate for dete,mi".Hnn ofLOlal capil,1 <oS! [or' partieul,rLechnology orcombinatioll, assuming moximnm IlJU' o:lJ"o,I)' ;s bo>«i OIl <"'>ling n,meplate mring. Single poin< rosL "Bure.' in 2006 doll.rs. (4)

_ E"''''''',d "'pHal "",1 [or fu'lCR poinl ",lim.Lo ",d fLOR pointe>l,m"', ",,;ved f'om D",,,,,bor 2004 budgelary propo"l byFud T",h. Soc APl"'odix C2 for deLaiL<. (5)

- The single poinL uniL oapilal '0.'1 [oclOr 'ho\\ll Ior Ihc ",dv,nced" version ofSOFA derived ffUm Bum' & McDonnell int'm.1 dalOb"", "nd ,ml osLIIrullo [or Nonh Daknlalign;'e_n"d 'yclono \K"iers (6)

- NESCAUM 2005 Technicall'oper, po.<led al Ihoir wobSlI<. S", Ic,bmc,l Te[mncos in Appendix Al for del,ils. (7)

- 'l'be ,ingle ]>Oi"lnLliL "'pi"l ,",I [."00- ,hoWll [or. ooo",nLional gas rebum system I"dudos Ibo ",'irnaloo oapilal "os! '0 in>I.JI "**bi~b-p,,,,uro** n,ru",1 gas ,upply pipeill," (llA S/kWj, and lb,' bulh boikr, shore Iho copiOll cost ;n pro]>Ortion to theirresl"'ctive raled**~1W** gross oulpul ,"V'citic,. (8)

- The ';nBlo r->inl Llnil ClIpilal cost [,clor sbov.lI for. Jigo,'e rehum ,yst'm is higbly silo-,pc,i['c, and asSUOle' lh'l new pulvcriz<:", and building enclDsures "" requ;reo. 

## n" gon"'''1 rost Iango [00- pulv<:rizoo ,,,,,l,fired boile" is indLKled in 'he NESCAUM 2005 Techni,al Pap'" [01" eyclono boilors is induded ll\me 2005 WRAP Drafi Ropurt, ]>OsLed '" Lneir web';I". The sins!o poinl unil copilal coS! factor roc ,hi, .1L"n"i"e fOr mere.sed PM collecrion <::lpaoity iocluded in hgni'o rcbum option" 75.5 S/kW. See I<choi""l rclCrcrlo<S in Appendlx AI for de""I,. (9)

- The Llnil "'p,Lal ro'l [a,lorr,ngo [orfLGR opplkaLion, 0" boiler,**wiL~out** an exi'ling a**~igb-prc"urc** n.=1 sao supply "'oo nol [uund in .""il,bl, te,hoioollilelature. °fl,e ,i"Ble poi"l nOli '"pil,l ,0,1 [,<101" ,hoWll for afuel I",," S'" Tebum ,ySl<m indudo, Iho cstirnlltcd capllal ro" 10 install a high-p",sstlI, nan,,,l gas supply pipehDe (15.1 SIl::Wj, and tho! holh 00;1,,,., ,hare**~Ie** oapi'a1 '0>' iu pro]>Ol1ion Lo Lbcirresp,crive ,"'ed MW S'OSS "U'PUl c'p'cili""

Bum> & McDoundl 3_ll Square**B~~o** Electric CooperativeNO" BACfAoaly.i., ShIdy BACfAnalysis for MRY Si;llion Unit 2 NO" Emissions


### TABLE 3-10
- Estimated Capital Costs for NOJ( Control Alternatives • MRY Station Unit 2**~"** • In=lledeapJlal cost;s ,,,im.ted fur determination oflol.1 c.pital cUS! for. paIli,u1or technology or

oombmation, as""ming477 MWg nnil eopadty 'llling. All cost ngures in2006 dollars.

• AnO".I;lod ,opila! 00" [1151a1lod capilol «)Sfx O.OS71S """ualized capital ""I fu:tor.

- Co,ts for go< robum options iod"dc high_pro"""" ""lural gas ,upply pipeline

# i.,

..llod eap;ta1 CO" of**SI~,98S,OOO** for CGR ""d 57,4\14,000 

### ror FWR: and unnu,lizi:d ""pi

..1""" 

### on 1,307,ooO/yrforCOil.

und $6,J,ooo for !'LOR. SocfuOlnol" 11-8 and 10 "ndc:rTable 3-9.

• Cm", fo; in<:ml5,d PM ,oll,ctioo cap",ily moloded in lignilerebum opli.o

## at, S36,0I3,O!)O rOTin,tlll'"

"'p;ta! 

### ""st. and SJ,I4Q,OOIllyr "",""IizrdcapilOt**oo,~** () 

## ") 

## (', «)

. (5) Insl.U.d**Allllnali~.d** Capilal Capital All. NOx Control**A.lIematl~e** Co,tV) Custl') Labelll) $1,000 $1,000 

# , SNCRwlASOFA 17,125 1,493 0 Go. Rebum 

### wIASOFA' 35,490 3,094 Lignile Reburn wi ASOfA' 

### , C 51,167 7.077 

# , Fuel Lean Gas Reburn 

### wIASOFA' 21,BI7 1,9ll2 A**Ad~anced** SOfA (ASOFA) 10,008 

# .n Baseline 0 0 

# ,

- A!I'llUlbvc label has been ""i ed rrnmbi L to lowestunitNCb; emission

### me. 

# "'

3.4.1.2 Operating and Maintenance Cost Estimates for MRY Station NOx Controls TIle operational andmaintenance OO/lts to implement the 

### variOllS NO

### x control tecMologies were largely estimated from cost fuctors (percrnrnges ofinstalled capital costs) established in the EPA's Air Pollution Control Cosl:MunuaJ (OAQPS) for SNCR"', and frompublished 

### in techllical papers discussing those controltechllologies. 

### ill the cases including various fonns ofSNCR, preliminary vendor qnotes 

### were obtained and used in pille< of, Or to adjust tbe OAQPS eost factors, Thcse cool esliJrul!es were cousidered to be study grade, which is 

## + or-30% uccnrncy.

Fixed and variable operating and maintenance costs eonsidered and included in each NOx control tecMology's aruma1 Q&M costs 

### are estimates of:

• Auxiliary etoclrical power cousumption for operating 

### the additional eonlrol equipment;

• Reagent consumption, and reagent unit cost for SNCR alternatives; and

• Reagent dilution walerconsumption and unit cost for SNCR alternatives.

'" EPA Offico ofAir Quality Planning andStandards (OAQPS) publioalion EP**A!~S2fB-.02.001,** Sec,iou 4.2, NOx Coulrols

- NOx Po5l-Cotnbuslion, Chapter 1 - Seloctive Nun·CatalyticRcduction, daledOctol>er2000, posted at theirwebsite: http://www.epa.gov/rrnlcalo/dirl/''-'4_2 ohLpdf &jure BUlIo Electrio Cuoper.otivo J·22 

### BllInS & McDotlIlOlllJACT AlUll}'"i., rur .\1lIY SI"IL"" 

### t;"il 2 NO"**Elni"i~,,,** RO\'i'cd 1011712006

•**[n~(~a"cs** or,m'ings in "uxili,,'Y d"clrical puwcr consumplion for chang", in cu"l prepamlion etluirmenl a"d lundLng-, prilnnrilJ' ror fLLel r"bum "a,c<;

• Gene",1 operaling**I~hur,** pill' mainlonallco bhor ;l[\(lm"lori"ls**tI~\'otC(IIO** lhc**addition~1 ~lllission**  comrol equipment anti ilS iLnpacl un "xiSlillg hoiler**e4uiplll~"'.**

• Roducliorr' in r"\'cnue expected m L.",ull from I"s" 

## or- unit avaibhility, i.c.**"\'ta!>~, altributabl~**  to lhe cuntrol "plion, which reduce annual nel elilctrical gcne",tion availahle for**s~1e** (revenue).

For economic evalualion purpose." an annual**~vemgc** runrriug**p[~nt e3p~dly**  f"elm of95.2 percent**~ompared** to a !luminal unit oulput capacity of462 MWg combined WLlh all avcrage**~nnual** av;,ibbility (uplime)**or~,229** opcr"ling hou", (9].9 percem of8760 hours per ycar) resulling 111 an annual unil capacity lactorof**~9_5%** were "",ulncd for Unil 2'" pre-conlrol ba'eline annual opemlion. A heat input mte of

### 4,885 mrntltlJhr and a NUx emission role of

### 0.786 Ib/mLnHlU ",e", assumed ror**~"ku["ling** control 

### nod co'l_effecl;**,en~SS** rrom pro-conlrol maximum rolling 12 momh summ"tion ofnilrogen LlxiLlcs' 

# m"" cmi"ion' for MRY St"lin" Unil 2.

T"ble ]-11 ,how Ih" ",Iim"leu annual operating and**m~inLcn"n"c** co'l< and icI'"lizod**~"n,,~1** 

### O&M cosl v"luc, 

### for lbe**hig"c"-p~r["onning** fonn of,he various '",",'ible NO

### x emi.,ioLl reduction tcchLl<llog-io$, These are liSIed in order OfCOLllrol**~ffcClivcno",** wilh Ihe hig-he'l**mnk~d** uplions "Ilbo lOp. The co,t**m~lhodo[ogy** summarized in Appendix Cll"ovi<los lnon: tlol:,ils I,'r the**1~\'e1i~cd** ;Inn",;] O&M co,t**ea[~llbtions** 

### 'llld**~()sl** faclors.


### TABLE 3-11- Estimated O&M Costs for NOK

### Control Alternatives
- MRY Station Unit 2 ,\nn",1 [.e,',liz,d ,Annn'[ O&M CO'I'" 0&1\1 CU'I'" All. label'"**;~Ox** CUlltrul Allemaltve Sl,OOO Sl,OOO 

# , SNCR ",I ASOFA**~,** lOR 10,125 D Ga, Rcbum "i ASOFA**~8.63S** 60,703 C LigLlilo Robum wi ASOFA**Y,n~ 12,J~8**  

# " !'lGI{ wi ASOFA 21,90'"**D,~II** A Atlvallm[ SOFA (ASOfA)**2,~U5** J.5OJ Ba<olino 

# " " 

# ,

- AI,c'[llilwc lobo! 

## "OS b"'on

# ""i ,«fif 

### " 

## . ( ) g cu,n b'oh"l '0 10"",,"nLl I'iO, "n">lOU "'\e. (2)

. ,Innu,t opcrnling**'LL~** L"a;nL,na,," 0051 [0(' p,nkub, Lcduwlogy 0' ,ombiLL"i," ;, "''''l,aced L" 

## ""i' b",lin' op<mlian al "",,,;".1 "oi' ,ap,oity (462 tIWg) aud ,,,,um,, "**~J.9%** "'''ago ,,,,,u,1 'I'a;bh,IIl" wbich L! bighest <o"",,eUul" l2-munLh, ofope",Lion from 200 1·2@'. All 

## ,"0." rigu"" in ,O[}l; Jolt"",,

Bum., & MOOOlllldl J-n Squ"ro Uullc fledrio C"opOmL;\'ONOx 

### BACT Analysis Smdy BACT Analysis forMRY Slation Unil2 NOx Emissions

(4) •

# Co,,,, for inoroa'od PM 

### ",ll"'lion <.pacity included in 

### ligmlc rebum oplion 

### ore**~J,35~,OOOfyr** 

### for annull!

. o&M**'OS~** and M,T94,OOOlyr annuali,.ed o&M ""I.



### 3.4.1.3 LEVELIZED TOTAL ANNUAL COST ESTIMATES FOR MRY STATION NOll: CONTROLS In order to compare a particularNOx 

### emission reduction allcmative during the initial engineering analysis portion oftheBACf selectionprocess, the SUm ofestimated annualizel! installed capital plus levelized :mnual operating:md maintenance eosls, which is referred to as "Levelized Total Annual Cost" (LTAC). ofexpected pollutantremoval byimplementingthat alLernative was calculated. TheLTAC for 

### all NOK 

### eonlrol alternatives was cal""lated based on the same economic condilions and 

### a20 year projectlife (see Appendix Cl formcthodology). The unit control cost was then determined as the LTAC divided by annual tons ofpoilutantemissiOIls thatwould be "voided by implemcnbtion oftbe respective altemative_ The control alternatives Werealso compared by calculating thc change in llIlit 

### cost (incremental cost) 

### per incremental ton removed for the nextmost stringent allemative. This identified whieh alternatives produoedthe highestincrement ofexpecled pollutanlrcduction for the estinmted lowesl average annual cost increment compared with the baseline cmi"sionrate_ 

### The e:<pcded annual number ofmus of pollutant removed versus estimated LTAC for each remaining oontrol allcrnalive was then plotled

. 

## .
The comp,ui<;on ofthe cost·effectiveness ofthe remaining NOx cmi,,-,ion reduetiOIl teclmologics was made and 

### is shown in Table 

### 3-12**~nd** 

### Figures 

### 3-1 and 

### 3-2 for

### MRY Stalion Uuit 

### 2. These figures plol estimated annual amount ofNOx 

### removal (emi"-'ion reducLIon) in 

### tons per-year on the ordinate (horizontal axis) and the estimated levelized total annual eOlll in thousands ofU.S. d01lam 

### peryear on the abscissa (vertical axis), foreaoh of 

### [he remaining NOx 

### oontrol technologies. PoinlS on the graph that are furthest 

### to thc right and closest to 

### the hori7.onl<l1 axi" are deemed more co"l-effective, sinoe they repr=nt oonlrols that achieve more NO" removal perdollar required for lotal annual oools ofoperalion. maintenance, Qnd capilal recovery (depreciation).
Although 

### the NSRManual repeatedly pre"cribes f91lowing a "lOp down" analysis approach for BACT**determin~tion,** 

### the development ofa least cost envelope wilh dominant conlrols (ns,;un in NSR Manual Figure 

### B-1, page 

### B.42) clearly labels points with loweremi"sions reductions and 

### total annual costs fir"t. i.e. "A". '"B", 

### etc. then prooeeding wilh labeling and connectingpoints plotted further nway from the zero emission reductionpoint. TIlls "bottom·up" approach is for plotting the le..,t--coot (dominant) control
curve. The labeling ofoach unit's NO" control tcclmiqne allemalive has followed this approach.

Square Butte 

### Eleelri.e Cooporative 3-24 BlllIls & 

### McDonnell8.\.CT .",""Iy'" for .lfl(Y SI''',(,n [T"'L 2 NO, F,,,i";"lL> [(e"ised 1011712006

------**~----** 

### TABLE 3-12
- Estimated Annual Emissions ii1nd Levelized Totiill Annual Cost for NOx Control Alterniiltives
- MRY Station Unit 2

(i) ,\ILcrn"LVO 10 ",,,gn," from hLghe.;L Lo low,., ","L Nil , (2)

_E"i'''''L,d ,""""I omission 'om nS>llme a" """,,"1 u,,;1 av"iM.ili'y [,,'ur ,p",ili, 10 c,eil ,1"maLh",; 9J.9% W,,, ,,,"m,d Ii" Lloe "",ehne ",c, (3)

_E,tlm,l,d ,"""I 'om ofomi.,,;ol\ "'d"'II"" i, th, <1if[erc",e 1>I;,,,,,,,,n ,nn",1 b"e1m' Lo", ,nd 'aeh ,,11""'''li''o', nnn",l 

## 'm''''o", (LC"'), (4) • Lc"oIi"d 1DLal Anl\"" 1'"." = Anm"li;ood '",,,,lIed**Ca~i",1** Co.,L , L<voli'eu ,\,,,,,,,,1 D.H[ co", S,,"**noLe~]** r"" I'ooks J_10 OJtd J_II 1\'''"m",]",,1 '"'" [,,,Ior>, omis"o"' or. "kolaL,d ,jom "niL ,,,,i,,i,," ,"'e" 'on'rol**~"'''"'''g<,** 1><,,,,ly heal iopol, ,nd a""",1**h,,~',** "rom'io" comp.",d Lo**~"_"''''LO''** "'",elm, b"e<J on ,,",ml "l',mL;un

" high,,, ,llowab[o p'<-c""lrol NO, cmi"ion "IC. (S)

_Mor's< 1'"",,,,1 CosL EIT",,'i"'"'" (S.'LO,,) " 'he l.e,'e1i",,1 Tol,1 1."""01 Co>' (IOUOS')T) Ji,idou 0)' ,\'n,,"1 Gom,io" R,ducL;"" (L"","y,j, All "">l ligllfos ;n 1006 dolla" (0)

_I.TAC fur ga' «oum Op,iOLl< .,,01"'[0**ni~h-J''''''''''** "''''lfal g" ,upply**~ip,lio,** onl\",Ii,,<d o'l,iL,1 ""I "I :> 1,3U7,U!J!),'yr for CGR "",I Sf,5J,UOO**~Iu,** I", fLl;R. S,,, [o"Lno,", ¥3 'TId 10 "n"or I,blo J·9 (7) ,Ll'M: 'br in,.-ea.,ee[ PM collc"io"**c,p",~'** melud'd in liS";'" ",,""" opLic'" '"' 'ppn",,,,,,'e!y SJ, HO.IJLJO fo, ''',mali'-"d ,apiL,1 eo,L pi", S4, 19',OOUlyr Ibr ann",li,.«1**O&~I** ,0,L, [0" LTAC "'010,,1 of**~7,JJj_OUU,** y', L.,-e1i,.d ._\n,,"al NOx TOl"1 Aver"g" A""ual NO., [,;Il,i"ion, Annnal Cont,..,! Alt, Cmi"'o",m Rcd"cllo,,'" Co'l'" CIl,t!iJ Lab.lll' NO., COnIc"!**Alt"rna~v.** T"ml T Ton"Ye SI,OOU Silon 

# , SNCR wi ASOFA 6,421 9,372 I 1,618 1,240 0 Ga, Rcbum wi ASOFA**6,~~2** R,910 (i3,3n'" 7,17 i C Ligolle Rebum wi ASOFA 6,96-1 S,S29 19,475'" 2,2M 

# , FLGR 

### wi ASOFA**~,490** 7,]03 29,J 17"') 4,014 A AJvoncen SOFA (ASUFA) 9,621 6,172**~,J76** 

# '" Baseline 15,793 

# " " 0,1 1",-, h,,,"

. <"",i.«io", r:lIe.

3-25NO,- BACT ,\nolysi' $louy Reviseu 10/171200fi BACT Anoly,is for MRY $101;011 Un;ll NOxEmi.,i""s



### Figure 3-1
-**NO~** 

### Control Cost Effectiveness

_ MRY Station Unit 2(1) 

# 1-------
Millon R. Young Station Unit2**NO~** 

### Control Annual Ramoval Vi 

### lavalized Total Annual Cosl 70000

60000

SOOOCl

40000

30000

20000

10000 A' Ad"'"""d S.p.",ted Overti"' p,jr

### (ASOFA) 

## e•Fuel Lean 

### Goo Reoum wi

### ASOFA G • lignite Reb"", wi PiOOFA O. G., Rel>"", 

### wlASOFA E • SNell wiPiOOFA



# , 

# . • o •

c



# • 

# , •**"L~~~** 

## __ () 100() 2()OO 3000 4000 5000 6000 7000 SOOO 9000 10000 

### Annual NOx Removal, tonsiyr 1_-

_ ([ I -All emL FLg""'" i" 2006 dolla". Numb<" "" li,t<d 'nd**~u,li(im** ''" oorod in Taole J_12_

The purpose ofFigurc 

### J_I is to show Ihc mnge ofconlrol and cost for all feasible 

### NOx rc,luetion allemotives evoluated. A dominant set 

### ofconlrol alteIllillives were delermined by generating whnt is called [he "envelope ofleo,t-cost alternative.'"

_ The dominant eonlrols cost curve is the best fit line through [he paine' Forming the**righlmo~t** boun<lol)' ofthe data zooe 00 0 <cacrer plo[ of[he anmml 

### NOx [cmov,d tonooge
versus LTAC for the various remainiog IlACT sl!emaHves_ Following a "bottom-up" grnphical comporison approach, eoch of[he 

### NOxcontra] technologies represented 

### by a 

### dam point 'a tbe len ofand above the least eOSl envelope are inferior oontrol allema'ioes pel the 

### NStt Mannal and should be excluded ,rom fu[ther**analysi~** on n COs! efficienoy basis_

Squ",c BOI[e Electric Coop"rative 3-26 Bum' & M"DolllldlBACT Allaly.", I'K "IRY SL"LJ"" lini, , N(h FIll;.,',i,,,,, Revised [Oil**JI~006**

-----------------
0("**Lh~** Ic",lmic"Uy ,ea,iblc NO

.. conlrol altoJ native, consi,lorcd [or MRYShlliull Unil 2, dala point, for**tn""c~Liom,1** ga,**[~blLm** (POillt OJ and fuel-looJl gos**",b~n,** (Ppilll 8) wiLh "dv'lIlced separJted over",e ui[, ond ligni(C ,chum wilh i\SOFA (Poim C). lay dislLnelly [en and**obO\'~ Lh~**  olher poinl' ofthe colltrol e<>SI point,' scutter plm ofFJgmo 

### 3-

### t. Thcse conlrol**op~ons** a[e inferior and lherefore woro elimillated Irom ("urthe[ control**cost-o[fecti,'en~'"** amolysi,.
Average and mcremcallli**"Jlnu~1** costs and 

### NO, emission re,hlO,iollS (o[ Ihe dominant le,,-,,-co't comrol allernalives remaining ,,["ter the climilllllion ofIhe ohviou;;ly inferior oplions arc li,led in Tobie 3-13. The "nmml NO

### x cOlllrollons per year, dividcd by Ihe tomllevelized annual CO"" yields an aver,IJ;C unil cost (S/ton). lncremeulnl eosl effecliveness i, a measure oflhc illerea,e iu margin"i eost el1cclivcnes< be/weeLl lWO specifio**~Ilc[n"li,c,.** The addilio,,"1 TOll' per year ofNO,**en~lrul** rdalivo to the previous apparent lea,l-cost ClliVC l>oiLll, divi,kd by ti,e increase in le"e1ized anLlual CO", y,eld,; an inc[emcnlul unit eo,l (Shon). Allerll"ti,"ely, lhe incremenlal cosl eCCeelive"e"" an"lysis identifie, tile mle or**chan~o** uCco,l**~ffee[ivc"e,.'** IVJIII re'ped lu [emoval beLlel'lS {i.c.,**,h~** slope uJ" tile**~nvd()pe** ofle"st-cost control al,e",ati,·e,. "1'0 callc<l 1],0 dllmin"nt <;<muol;; co,t clll've or DCCq belween I,,<:ecssi,cly more efrective allernatives "hieh ",e "oll,idcre<llechnie"lly feasible 

### for "'Ii[,on R. Young SrnllO[] hoilcrs.


### TABLE 3-13
- Dominant Controls Cost Curve Points for

Feasible BACT NOx Alternatives
- MRY Station Unit 2

() """ 0 n P (SOA)uh,gh,,1 J.12. ,nd oa Lho S"pIOl 'h., ""unlpnay thi, ",ble (I'oin" lJ. C. ",d D "'"" el;m;m"d), (2) All ,ost liguro, in 20[1'; ,loll,,,, (l)

. AllJlUal e",l",ion red,,"i,," "od belj"d OOJ1lrot ,"os[ oruo"", al'om,L;'o, " T<I.tLVo <0 «'ITO", oom 'o1d pro.Gonlfol uniL MCR bmlinc emission "Ie. lq)
- IncremenL b,,,"{] "11Ol' """p,,,i,on bel",c" ,0m","tLv, ,1«maLh'", (p";n") r,,,,,, lowo>, '" high"", CJlocpL "**no"~.** Incrcmenl,,1**L.,·.]iLe~** LCVC][lOd Incremenl,,] '1'01"1 Annual Tnt"l Ann".[ Inoremenl,,1 Annu,[ !CUlls,loll Annu,,] E",i"iu" Con,,"ol Co,t ,\It. NO, Cu.'l"""**ne~ud]()n'H** Cost'''''' ({'duelio"'"**IW,,"(j,"em.~'** Lobel'" Conlrol**T,chni~u.** (SI,OOOlyr) (Ip.") (51,000l)r) (lp)) (S/tonJ''''''


# , SNCR wi ASOFI\**11,61~** 9,]72**7,~42** 3,2UO 2,26]
A ,\<i"o1llced SOFA 4.376 (,,172 4,376 6, I72 

# ," (ASOE'A)



### , D" 

## "" 

# '" 

# "" b '051 cur", ol""\ 

## r,."", [,,,,,,, A C 

# , ., 'SNCKwl

.. \sOJ-A ar,**labele~** Lh,**~",.e",** inT.010

The incrcmcnlill "",l """ly;is indicatcs lhllL from a co'l dlccti,'c'\eS< viewpoinl, Lho SNCR Willl "SOFA alteTImtive ioo",s " significant allllll:l I (levclized) incre",o,llol eusl "omp,,,e,1 to the ASOFA NO., COL\I",I
Bl1m, & McD"nndl J·1'1 Sql10re Ilullo Eb:lt1C Coop"ral'\'<**NO~** IlACT Anoly.,;., Swdy Revi,ed 1O!l7nUU6 BIICT Al1aly,i., LDr MRY Slolion UI1il2 NOx Em;«i(lLl,

tcchnique (slop" lrom zero baseliue to ASOFA, Point A was $709/tou for MRYS Unil 2; the incremental cost (slope) from ASOFA, Point A to SNCRwith ASOfA, Point E 

### wu< $2,263/ton 

### for MRYS Unil 2.
Figure 

### 3-2 oOn\ains a rcpcLition oflhc lcvcli2Cd tom] annual cmt andNO

### x control information from Figure J-I for MRY Station Unj, 2, wj!h Poinl B (FlGRTM wilh ASOFA), Point C (Ugnilc Rcbum wilh ASOFA) and Point D (convcntional gas rebum with ASOl'A) remove<l This is Ihc dominant controls oost curve 

### for MRY Station Unit2 NO

### x emissions alternatives. 

### Figure 3-2
- MRY Station Unit 2 NOx Control Alternatives BACT Dominant Controls Cost Curve!l)

Milton R, Young Stalion Unit2 NOx Control Dominant Controls Cost Curve



# \

-'

..

### _.- B,OOO

2,000 5,000
4,000 10,000 14,000 

# ,-------------------C,-, Slop. = Inorern"n"'l SI"'" (poi"" B. G. ond 0 rornowdl 12,000 A. Ad",",.d S.poro!Od O""fire Air (ASOFA) E_5NGRwIASOFA 

# -

o 1,000 2,000 3,000 4\000 5,000 6,000 7,000 3,000 9,000 10,000 Annual NO. Removal, tons/yr

(1)
- All ,osl flgufCS in200G doll,,,, Numb", oro li"oo ""j qua[;LLm ""' "o"d inT.bl" J-ll

In**ih~** U.S. EPA'. NSR Manual, the EPA docs no! ,pecify .cccptubic or unaccoptable range. for average (unit control costs) and increment"l cost**efl"ctiv~ncss** valucs. A, can be secn lrom" review ofT"ble 3-
Squa,e [lulle Eleolric Cooper.,ivc**J_2~** 

### !:Iurn, & MeDonnell8.\('T AO\,d,.,i, Ie" MRY Slali,," L",,"! NO, F",i"i""1**Revi,~d** 10117/2006 NO, UACT r\llalv.'" S!lIdy

14, the**~vomg.** levelized conlml cO.<l cCll;cli"eness (called lhe ullil CQl\lrol co,l in loi, reporr) ml\g:c, from "pproximmcly S709/loo 10 $7 ,1711ton ofMRYS Unit 1', NO, cmi"iom removed. Ir slluultl be nOled, however, that Iho highe,t e,timmed aver"gc eOlllwl co,t, involve gas rebum technologio, that wcn; shown 10 be inferior option, (nOl all rhe**domJJl~nt** conlrols Co,l cmve) aod thus wc"e eliminated from [urlher impucls analy.;,.

Thc incremcolul oo,t cffe<ori"cne" i. a measure oflhe increa,c in margin" Ieost**~nectivenc"s belwe~n**  two -,pecific alternalivc,. Alternat;vely, the incremenl"l cosl efl""tivenc,,", analysis ideotifie, the ralC of change ofcosl eft"ccliVCness wilo rcspeCl IO rcmo"al bencfits (i.e.,**th~** .Iope ot· the lcast_to,t**cDv~lo[1e** of dominant oontrol alrernaIive, Or dominant control, cO.,t curvc) bolwcen successively more effeclive alternaIives. The economic impact analysis in,lioales Ihat from a eo.,t cffecliveno" viewpo;nl, Ihe highe,t per[bl1ning alrernativc is SNell.. "iro ASOFA (Polnl E). This oumrul oplion is considered**tec~icarry** fC;lSible for Milton R. Yoong "lalion Uoit 2 boiler 11m incur,; ,1 ,ignilic,mt "nlllml (levelizc(1) incremental cost rclat; vc 10 lhe ne.'l oighesr t'ea."bk NOx conlrol technique, A"OFA (roinl A) "hen ASOFA is compared against ;hc pre-o"nlrol ba,elinc. Tlte**l\d\'llTlo~d** SepJm!ed Overtire Air**nltcrnuli\'~** I", aLl uver"ge ul1it conlrol enSl**(~709lIun)** upproximolely 

### 5R%**ol-th~** higheST performing leasiole "hema(;ve 0[1 the uom;rumt conlrols co'l Clm'" (SNell with ASOl'A, $1 ,:'40110n). ASOFA al,o has a mu"o lower incremental oO.'l pcr lon r"bli,'e TO lhc l'J'c-coIIl",1 b",elil1" (,lope from zero tn Poinl i\, 5709/lon) compJJ'ed 10 SNCR willt ASOFA (Point [) vcroU, ASOFA (Point A); Ihe <lore I""" Point A to 1'0"11 E
was 52,26]/toO\.

The other elcmcnL< "r 100 rounh srep ofa BACT ',lm1ly5i< following economic i",pooLs ',Ir" to**~V"lualc** thc following impact, ol"lea,ibl<: omission controls: Too el1<rgy impacl'.

• Thc cllvironL11"l1lal impact,.

Bum' & Mcl)onncll ]-2')

## , 

## I 

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## •NOxBACT Analy.is Study BACTAnoly,i. forMRY Station Unit 2 NOxErnissinn.



# • 

# !l

,.


# • 3.4.2 ENERGY IMPACTS OF MRY STATION 

### NO

## x CONTROLS Operation ofthe mosl oost-effectiveNO

### x controllechnologies considered feasible for potential application atthe Millon R_ Young Station Impose directimpads on the C<lIlsumption of

### energy required for the production ofelectrical power nt the facility. The details ofestimated energy usage and costs for the various NOx control a][ematives are snmmarized in Appendix C3.

Control alternatives for reduction ofNOx emissions were reviewedto detmrnne ifthe use ofthe tcchnique or technology will result

### in any significant or unusual energy penalties orbenefits. There are severnlbasic 

### kinds ofenergy impacts for NO

### x emissions controls:

• Potential increase or de<:rease in power plant energy consumptionrcsulting from a change in thermal (heat) energy 

### to neteleclriC<l1 output conversion effioiency ofthe unit, usually expr=ed
as an hourly unithealrate (Btu/kW-hr) or the inverse ofpounds ofpollutantper unit e1ectrio.a1 power output (MW-hr). This may ormaynot ohange the net electrical output (MW) ",,-paoity of the EGU, depending On ifthere are physical or imposed limits 

### on the lotal heat input to the boilcr

or elecTrical power outpul. Potential increase or decrease in net electrical output oflhe unit, resulting from changes in physical operational limitations imposed on the, ability to sustain a fuel heat input rate (rrunBtuIhr) which results in a potentiallylower orhigherunitnel elcotrical output (MW) capacity. This i. elTcc\ively a changc innet electrical output (MW) capacity ofthe EGU. Potential increase or decrease innet elccTricai output ofthe unit, resulting from changes in auxiliary electrical power demand and usage (kW, kW·hrs). This is effectively a change innci ele<:lricul output (NlW) capacity oflhe EGD.

• Polential increase or decrease in reliability and availabilityto generate elecTrical power. This 

## t.., results in a change to the number ofhours ofaIUlual opel1ltion, notnece.'<SlIlily a change in net eledrical output (MW) capacity ofthe EGU.



### 3.4.2.1 ENERGY IMPACTS OF SOFA TECHNOLOGY There should notbe a major impact on energy consumption resulting .from the operation ofthe advanced variation of

### a separllle<l ovedirc air system. SOFA 

### does not signifiCllUtly change the total 

### amount oEair introduced into the boiler, only the location where il is introduced. Damper resistance and supply pressure Impacls ofthe SOFA system on fan power consumption should be insignificant. The arnOlUlt of ilyash cmitted from the boiler is expected

### to be reduced (less than five percent) from the baseline level
SqllMC BUllo Elcrmo CO<lp<:rative**~.~** I Bums & McDonodlBACTAualysis for MRY Slal;on Urul2 NOx Emi

..ions NOx BACT Analysis Study

when Ihe SOFA sySlcm is in full operation. Slightly higher levels ofunbllmcd curbon 

### in**~,e** f1yash may oocUr with lhe operation ofa SOFA 

### system. This could have a small negative impact on the plant heat rate (higher BtuIkw-hr). These changes are expected 10 be wilhin thc typioal runge 

### ofGurrent operalion.**Th~.c** is a pOlential reduction in**re]i~bility** and availabilily ofa lignite-fired cyclone b<Jiler 10 generate sleam lor produotion ofe1cotrioal pmver as 

### aresult of**insl~lling** and opcr"ling a separuted overfuc air system. Typical SOFA operalion on bituminous or we..,lern subbituminous coal-fired cyclone hoilers docs not carry a signifioant additional riSK ofcausing imufficicrlt or excessive accumulalion ofslag wilhin the cyclone barrels or furnace boHom compared with non air-staged combustion. Reliableboiler operation depends On avoiding suoh adverse conditions in (he cyclones and lowerfurnaoe, whieh oould -'. require a forced oulage to remove lhe .olidified slag prior 10 returning the boiler 10 genernlionproduclion service.

The challenges ofmain!nining adequate slag layer developmenl nnd now while firing lignite in 

### MRY Unit 2's cyclones under excess air oondilions have been significanl dUling the operating histOly ofthe powe'l'lant. Minimizing forccd outages resultmg from cyclrme slag issues havc largely been .uccessful lhrough**op~·mtional** practices that do not affeot**d~Y"lo--day** boill' reliability and availobility. Due 10 the ""riability ofcombustion characleristics oflignite supplied from the Center mine, and the dependency of the slog now Oll the lemperaturc "filhin the cyclone barrels or furnace bOllom,**~ondilionslllay** O"Cur dming ASOFA opcrntion that exceed the ability 10 adjust opelllLional practioes sufficienl1y to avoid foreed outages to remove lhe solidified slag.

The**polcnli~l** impuel On annual unil operating lime doc 

### to cyclone slag issues associated \Vith nir-staged cydoneslASOFA system operalion W"S estimated to be approximately 2% reduction from lhe assumed pre_control baseline avallabilily, i,e. 0.94-0.02=0.92_ The eSlimated electrical b'ellCration produclion lost dm: to the reduction in 

### IvlRY Unit 2's annual availubilily is shown inTable 

### 3-16.



### 3.4.2.2 ENERGY IMPACTS OF SNCR TECHNOLOGY Fur SNCR, (he injection ofa dilutedurea solution will require some addilional mn:ilial}'powerfor heating andpumping the liquid and using compres.o;ed airfor atomizalion and cooling lhe reagenl injection nOZ7.1esflances, on lhe orderoflOO to 300 kW. The injection ofwaler(used for urea dilution) inlO lhcboiler nuc go' also will have a small negative impact on theplantheat rale**(high~.** BtuIkw_hr), although the vandor ofSNCR "J'Slems advises thallhc heat released from the oxid.tion ofa portion ofthe

Bul'Jls & McDonnell 3_32 Squaro**Bu~e** Electrio Cnnpemlve**NO~** BACT Analysis Study BACTAnalysis for MRY Slallon UnitlNOx Emissions



# ,-- 

# ,



# , , , 1

, ,



# , injecled urea compensates for lhis impuct. The impactofadditional flue gas oreated by operation ofan SNCR-related system On fan poweroonsumption should be small.

There is a potential redUClion in reliability and availability ofa lignite-fired cyclone boiler to generale steam for production ofelectrical poweras a result ofinstnlJing and operating a SNCR-rclalcd system. Typical SNCR operation with low anunonia slip when firing low-sulfurwestem subbiturninollS coal in cyclone-fired boilers does nol cnrry a significant addilional riskofcausing excessive fouling of

### the tubular air prehealer oompared withnon-SNCR opemtion. Reliableboiler operation depends on avoiding adverse fouJing condillons 

### in the air preheater, whioh could require a forced oubge 

### to remove the ash deposits prior to return.ing the boiler 

### to generation production service.

The challenges ofmaintaining open passages througb the airprehentc:r tubes while (Iring lignile in MRY Unill's cyclones unlJer typical conditions have been minor during the operatinghistory ofthe_ powerplant. Minimizing fore;ed outagesresulting from ash deposiLs within the air preheatcr have largely been successfullhrough operalional praotices thatdo notaffect day-to-dayboilerreliability and availability. Due to the variability offouling characteriSlics oFlignite supplied from the Center mine, and ,_the dependency ofthe Conling within the air prehealCTon sodium, sulfur, nnd ammonia slip emission ,_levels,'conditions may occur during SNCR operation that exceed the ability to adjust opel1lHcnaipractices _sufficiently 10 avoid foroed oUlages lo remove !he airpreheater deposits_

### The-p~ienHal impact On annual noit cperating time due to airpreheater fouling and o!her polential issucs associated withSNCRsyslcm op=tion 

### was estimated to be an incrcmenlall% rcdudion from the assumed pre--oonlTol baseline or

### ASOF A availability_ The estimated elecll:ioal generation production lost due 10 lhe reduction in MRY Unil2's annual aV3ilability 

### is shown 

### in Table 3-16.

Square BuneElectric Cooperntive J-JJ Burm & McDonoO]lBACT ALlLlly"i, (or MltY St,,,ion ULlil " NOx ELlli5S10Ll3 Revised 10/1712006**NO~** [lAC I' ,\ual,.,", SLLtdy



### TABLE 3-15
- Expected Auxiliary Electrical Power Impacts for NOx Controls
- MRY Station Unit 2

pr 0 pg (l)
- The APC**NO~** eq"ipmCllI gross ,u,moLy do"'i""l p"wer do""nd o[,!LemaLi"e.< j, II" "'''' n[indi,i<lll,1 Icdmologic, """,bi""l by ,imple ,ddiLion AcLual row", demdml, ""'y diff<r [rom Lhl, du, (0**~",ilivo** ur neg.,liv< ,ynergi,nc ,!fuel<_ (JJ

- Th" "n",,"1 chong< in APC "Ux equipm"nL "uxili,TY o,,"<lrioal powo, "emat.! oh'nmLy ""ge '" kW-hrslyr [or Iho," "l"'maLi,'o,,, Inc neL po",,, demand mulupli." by Ihe ",ILmated OI\Ill"( o!,ornLh,s Lim, ""I running pl,nl e,p,eity loeLor wbien**"'~cc"** <he adjll!ll\lenL [Dr any "pc<",,1 rcli,bilLty ,nd ,",p,eily ill'p>cL, f'om lhe lmplcmcnullion ofthe o<Inl<ol ',chnLq"o, An<g"iv, rc'l!ucLio", il\ g,n"""Lm i, an incro",e ;n ,nn"al 

### ,,'w de,"io,1 po"or ,,,,ilablo for ,01,. '**E,Umale~** AnnuLlI A**Ycrn~c** '\Ilxiliary EI.ct,·ical rowor Domond and C"n.<lImplion 0(1'10. Cnnlrol E 

# ., mcnt Geo_" Alt_ D,mund(!1 rower U"a<(l) Lnb.I(I) NOx Con(rol TechniQLle 

## 'W kW-hrs/;'r 

# , SNCR wi ASOFA 133 I,OOR,774 A Adyanced SOFA (AS01'A) 

# , 7,(,(>'1 

# '" AILem'li,'" "uml:>crh", beo" oviornly ,doned fn,," ic.,t «mnl',1 Lo h;.he." ""'<lVill "'",nt, '<,



### TABLE 3-16
- Expected Electrical Power Generation Availability and CapaciLy Impacts for NO;.: Controls
- MRY Station Unit 2

( ) n"mo"

_ g [",m I""" ",mm

.. 1Lo 0 ( ,I p<ITcnlage. (2)**~,""Ii",** ''''d;ldbility i, ",ume<! " 9J 9I"""nl The," v,I"e:;**"'~CCL '_I,i",a"~**  ""'ollnl> ufneg<LL"-< rciinDiILty**lLU~"L** e'p,<I,'I! [rom Lho imp('''''"L,li,," ,,[Ih< individual NO, ,0nLrul**'""hn;~uc,** (J)

_ Annwllu" np"rnL1J\g L;m, ,,-,<"ILi,g fcum Ihe impkmen"Lioll OrLllo**i,,~i,iu",,1** NO, eon'rol Lochnlquc i, Ihe dln;,c<o," b<I\;c<o the b,,,lio' and expc<I

..1onn,,,1 olll,ge Om". (4)

_ 0"",1>,< ","ning**~lal\L** C.l"'dly fa""c i, ,,,"umed ,I 95,1 perceill. Tho"" v,I"""**",~oe<** csLim"cd atUOU"" o'-"'g:lli.e ",Ii"bili<y Lmpa" ,,-,p,,',,1 

## r",,,, <he imple",ou"Lion o[ Lh,**io~lviclual** NQ. ccnlrollCcluuquo_ (5)

_An""ol dC<lricil}' geoe,",i"" t."h"Lio" i, "nnu,1 ,,-"dUCIJO" uf**01"'ruLin~** lime mLLI(lph,d by LIl, .0"",1 ",,,,,i"g**~I,m(** e,p'city faeLM ,o>lliling [rom the imploll\o"",jo" orlho i"Ji"d",,1 NO, eonLrollod"'iq"" H",IL;pli,J by <ho MCR e'p,my "'Ling of**~bl** Mil' IMCR gro>s lIniL ek<:LfJe,1 OU'pUL**c"~,cily)_** Estimalod**£,Ullla(,~** E,timal<d Annllal**A"nll~1** ,\nJlllal A,'o;"go**AV<l-a~.** Avorogo**£s(in"llC~ Oporal[n~**  RLilinillg Elodridt)- Ann"al Ti,ne Pl,llt (:cooratioll Alt, ""'mge ll.oducljoll, Cap.city ll.edll"inn L"bel(L) NOx Cnnlrol Tecnni, no rI ",il,bililyL!) h,-,I>r(" FLlctort<J**kW-brslvr<~** 

# , SNCR, wi ASOFA**O_90~** 

# '" (J_9'; I liO,176,095 A Advallce<J SOFA (ASOFA) 0,919 

# '" O,95l 75,859,855 

# , ,11"''"''-''0 h"" be," ""';ou-<lv",,i 'ood 

## .. hiollN rem ,n

8ums & Md.l"LlIldl H-I Sqllar< Hulle**~k'Clr;c** CuupcTOll\'cNOx B",CT Anoly,i, Study Rcvi;cd 10}[712006 BACT ,\nalysi, for MRY SIano" Doil 2 NOx Emissioos



### TABLE 3-17
- Expected Total Electrical Power Generation Impal:ts for NOx Controls • MRY Station Unit 2

(I) A[rem,L, 0numb,rba, boca prevlOu,ly a"\gn,d from 1.0>1 removal to hLghesl removal pe""ntaso. (2)

_ The ,""utll ,hang, io APC No,; cquipmcnl ,uxi[i,ry cleolrioa[ powc, dem,nd olec<rlcity usoBo in kW_hrsiy, [0' tho", ,I"",allvo, ;, 'h, ncl POW" dc,,",nd mU[I;p[ied by Ib, c.s!im,tcd "onu,1 opcmlirlg Limo ,nd ruJ,"lng pl,nl cop,clty [""Lo, ,vhkh ",ne,," lhc ,dju,"",nl [0' nny ""pe'ledre[iaiJility nnd ""p"eiiy impaots [rom tho imp[e"",nlallon Dflhe conLrol l<Chnlquo. A nogalivc reduolion in ge,",,,,lio" is ,n ino","", in ""nnal now el",rioo[ pOlver ovailah[e Ib, ,,[e. P)
- 1\nnnal ,lc,lrioiiy generanon reduction is ,no",1 rcducri"u ofoperaLing ,ime mulLiplied hy ,ho ""ou,1 fUllnin'g p[anL '"l"'Oily f",hJr ",,"['iog from <h.**;rn~[emooloLio"** of,he i"di,idnal NOx rontrol techniqu"**mulli~llod** by the MeR copadty "Ling of462 MW (MCR gross u"iL .[ecLric,1 <>UtpUL cafl'lcily). (4)

_ Annu.l ,h,ngo i" "cl.[o,lrica[ power g,nc,,",ion .v,lbh[, forsolo is ",I<hm

..i, oum ofannu:>J pow« seno,,"lon «JuClion**~no** I" • ch,ng, in Ihc "mili,ry cl"lricol power c"ruomcd p[u, <he ,"nUllI g,nemLion reduction 11"0L" a doc",,," In an"",[ opOl"'i,g 'im ,nd ,vc"'go ,nnnal mnning p[anL ,apodty f"CLO, re,u[,lng lrom the Iml,lernoo",li"" ortho**i"~i";~nol** NO' 'onlro[ I,ohniqu', ooml"'red w[<h boselin" I'stimaled Anoual**Avera~.** Est. Annnal I'leelridty Change in PGwor Geo'rotiun Net I'Ieelrlc.lPo

..er AU. Us"!!e!!) Reduction'" Generation Availab[e ro< Lab.l'll NO, CGmrol Tocho[ 

# "' k.W_hr'" r kW_hrsh< So[.'" kW-hrsl r 

# , SNCR w! ASOFA**[.00~,774** [ 10,176,095 [11,[84.869 A Advanced SOFA (ASOFA) 7,664 75,359.855 75,R67,520



## " 

## .

3.4.3 

### ENVIRONMENTAL IMPACTS OF NOx CONTROLS
- MRY STATION Nitrogen oxides reaci wilh oxygclI ill**th~** almosphc,,", 10 produec**demen~11** nitrogen and ozone (OJ). This is on.e_\Ifthe common CallSeS ofvisible pollu[icLl in the atmosphcrc ,ercrrcd 10 

### as "smog;". Opcro!ion of thc -:arions 

### NOx cOn[m!lechnologies cO.ll5idered for potenti"! application "t Ihe Milton R. Young Station impose direct and indircet impacts 00 [he environment. The most pronounced direot environmen["l impact e"pee[e<! from operalion ofany oflhc NO, conlrO!**option~** considered is the reduction ofozone and improvement in atmospheric visibility (i.e. reduced visibility imrairmcnt) downwind oftbc**f~dlity.**


### 3.4.3,1 ENVIRONMENTAL IMPACTS OF SOFA TECHNOLOGY The operaliOLl of"**~ep"rntcd** overfire nir system is e"peoled to sligh[ly increase oa,bo"**monoxid~** concentrations in**lh~** slnck fluo !idS. The ;ldvanee<i fonn ofSOFA alternative is expected [0 sligluly lowcr [he "mount ofparticuln[o mallcr omitled frum tho boil<:r ond may rai"" [he amount ofunburned carbon in Ihe El.ynsh colleeted for I"nd disposal ond emilted (0 the**atmo<phcr~** by snloli ineremen[s. AiLcrnntives involving fonns ofga, rebum should**~xpcrience** lower palticulate emi,.,ions, .nd ;1 reduetiun in [he umount ofboiler bottom aod (lyash rc4uiring: disposal.

Sq""", lIullo Elcclric Cooperative J-J5 Bum, & McDoollellBACTAual}"I,' fur MRY Stalion Unill NOx Emi«iOlL' NO_, BACTAnalysis Study

The enviTonmental impacl from potential redllction ofannual unit**op~TIlling** time by approximalely two percent due Lo cyclone slag issues associaled with air-staged cyclones!ASOpA system operalion will be 

### to reducc thc annual amount (tons) ofnitrogen oxides emilted, and**tllerefor~** lhe annual numberof

### NOx tons removed will increa,e, by approximately two percenl.



### 3.4.3.2 ENVIRONMENTAL IMPACTS OF SNCR TECHNOLOGY Operation ofa oonventional SNCR syslem is nol expected 10 .,igni[ieantly impact emissions ofCO or volatile organic compounds (VOCs).
Operalion ofan SNCRsystemwill normally creale a small amounl ofunreaoled nrea Or ammonia to be**~mitted.** The amount ofarnrnonla slip produced by SNCR depends on the amOUnt ofreagenl ulilizalion and localion ofthe injeclionpoints_ Higher SNCRNOx reduclion rerforrn.nce involves grealer umonnts ofreagenl usage und arrunonia slip. This i, typically wntrollell 

### (0 less than 

### 10 ppmvd, especially whcn the possible fonnalion of**~ulfalcs** such as ammoni\lm s,llfate [(NH,),SO,j and ammonium bisulfale [NIl,USO,] w,lI be more problematic at highe, slip levels. Sul[ur trioxide (SO,) formed during cumbu;tion in the boilcr can combine with ammonia during**pa8~agc** through Lhe flue gas dUClwork to form the sulfates.

Some ofthe unreae1.<:d ammonia from SNCR**op~"Talion** wm he onllCClcd with the !1yash in the e1ectroslaIie precipitator_Any rcnmining anuuonia 

### slip lhat is not collecled Orcondensed in the air pollulion control syslem will be**~"UIitted** from the srack as an aerosol or condensable particulale. This**ha~** the polenlial to iner.:a.>:c**"tmosph~ric** visibility impairment downwind ofthe fucility compared with a**pris~n~** oondition. Allhough thc predicted amount ofsuchpotential impact !Tom ammonia slip emission. has 

### not bcen**d~termincd,** it is expected to**b~** small in comparison wil1l1hc significant anlicipated reduelion in far-ficlll ozone and**improvem~-nt** in atmospheric visibilily as a result oflhe overall NOx emission**reduc~oLl.** Delivery ofthe urea reagent 10 lhc powerplant facility Jnd slorage ofaqueous urea**r~agent** on-site creates the potential for uCGiden15, leaks,**~nd** subsequent relea:;es 10 3ir, ground. and surface waler irrunedia1.<:ly surrounding the facility. Urea is muehless volalile th.n anhydrous or aqucous ammonia, and these risks
are expected 10 be manageable. Emergcncy pl=ing and communily communicalions urc part ofthe management plan rcquirements for such reagent llsage. 

# '.

,

[1= & McDonnell J-36 SqLlllre Bulle Blccl,;c CooperativeNOx BI\cr Analysis Study BAcrAn<tlysis forMRY**Sl:l~on** Unit2NOx Emi

..ions



## 3.4.4 The environmenlal impact from potential reduction ofannual unit operating lime by approximately one percent due La air preheater fouling issues associated with SNCR system operation will be 10 reduce the annual amount (tons) ofnitrogen oxides emitted, and therefore the annual number ofNOx tons climinutccl relative to the constant pre-control emission baseline will increasc by approximately one percent.



### SUMMARY OF ECONOMIC, ENERGY AND ENVIRONMENTAL IMPACTS OF MRY STATJON NO

### x CONTROLS The economic, energy, and environmental impacts ofeach feasible BACT alternative evaluated forfhis study is summarized in this Section_ Table 3-18 summarizes the various impacts discussedin Sections 3.4.1 through 3.4.3. The economic analysis examined the capital costofeuch feasible BACT allcmative evaluated and any otherpowerplant upgrade costs necessary to implement the alternativc. 

### Tn addition, the economic analysis examined the operating and lIIllinl.enance cost associatedwith the highest-performing forms ofeach feasible BACT allernative evaluated. These costs were then combined into 

### the levelized tolal annual cost for a comparative assessment ofthe toml implementation cost ofeach alternative_ ----!<'mally, 

### as pari oTThetop-down analysis,adOm.nant controls cost curve 

### was ploUcd-ancnlie unifcoiitrol----

--- --- cost

# fOr each alternative was evaluated. Two alternatives were on the dominant controls cost curve and thus were identified as the more cost effective alternatives. The two BACT NO

### xcontrol alternatives evaluated for incremental cost, energy, and environmental impacts applicable (0 Milton 

### R. Young Station 

### Vnid were:

• Selectivc Non-Catalytic Reduction (SNCR) combined with a special form ofseparated overlire air (SOFA) specifically for lignite-fired cyclone boilers (:referredto as Advanced SOFA or ASOFA); and

• ASOFAalone.

Squaro ButteElectric**Coopel<l~ve** 3-37 Burm & McDonnellBAcrAnalysis [or MRY Sl:llion Um, 2NOx.Emission< NOx.BAcrAnalysis Study



### 3.5 BACT RECOMMENDATIONS AND CONTROL LEVELS - MRY STATION UNIT 

### 2 This report pres.nts thc analysis ofcontroltoclmologies for nitrogen oxides (NOil forMinnkota Power Cooperative's (MPC's) Millon R. Young Station UnH 

### 2 using lhe EPA's**'~op·doWJl"** BACT approach. BACfis an emissions limitation roreach pollulant from a source determined to be achievable using conlrol tecb.nologies(s) lhalprovide the '·maximum degrce ofemission reduclion .,laking into account energy, environmental, and economic impacts"'". A BACT review does nOlresull in a percentremoval efficiency requirement. The generally accepled procedures for performing a BACT analysis are outlined inIhe EPA's draftNSRManuaL The BACfanalysis for Millon R. Young StationNO" emissions was performed in accordance with this procedure. The EPA's dr.:lft NSRM.nua] oullines five bJsic steps that are to be followed in the "top-<lown" HACr evaluation. These steps were 

### as follows:
Step I -Identify All ControlTcclmologies Step 2 -Eliminate Technically Infeasible Options Step 3 - Rank Remaining Control Teclmologies by Control Effectiveness Slep 

### 4 - Evaluate Most Effective Controls 

### and Document Rcsulls Step 5 - Select BACT

The final result ofthis analysis is a recommendation ofthe BACT alternative and the associated NO

### xemissiOIlrate for Square Bulle Eleclric Cooperative's Milton

### R. Young Station Unil2. The emission limitationa for a generation fucility

# = expressed in a poundspermillion British ThennJl UnHs (lblnunBtu) basis.



### 3.5.1 UNIT 2 NO

## x BACT In Slep one ofthe teclmolog)' evaluation, three basic catcgories ofNO

### xcontrols forEGUs wereidenlified; prc-combustion, combustion, and posl--combustion. Eleven basic types ofNO

### xcontrol processes were identified wi'bin tbese three categories. Twenty four variations oflhc"Sc cleven processes were reviewed for aV<lilability and applicability to cyclone-fired EGUs burning North Dakola lignite. An ··advanced" form ofSeparated Overfire Air, alone and 

### in various combinations withLignite Reburn, Selective Non-Cmalylic Reduction (SNCR), Conventional Gas Reburn and



# ., , Ibid, NSR Manual B.l Bum' & McDonneli 3-39 Sq=Bulle Electric Cooperative

### NOx BACTAnaty.,is Study BACTAnalysis for '"illY Sllltion Unit 2NOx Euri.<sions

fuel Leun Gus ReburnThr. wus "valuated for cost-effectiveness. The cost-effectivenes

.. , analysis indicated lhul ASOFA alone, und ASOFA with SNCR were costeffeelive "llematives for MRY 

### Stalion Unit 2 

### NOx control.. The energy and environmental impacts analysis for

### MRY Station Unit 2's cost-eiTcc!iveNOx 

### conlrol oJ(cm3lives were genemlly insignificant..

Based wpon the definition ofBACfund the results ofthe BACT analysis, Scleclive Non-Catalytic Reduction lSNCR) 

### in combination wiIh 

### aspeci·.l form ofseparalcd overflre air (SOFA) specifically for lignilc-fircd cycloneboilers (referred to as Advanced SOFA or ASOFA) i" recommended 

### as the Bcs! Available Conlrol Tcchnology for nitrogen oxides emissions from Square Butte meclric Cooperative's Milton R. 

### Young StaliouUnit 2. The unit 

### BACT NOx 

### emissions rule for .M.RYS Unil2 i" 0.330 Ih/mmBlu, determined as a rolling 12-month averagc. Thi" is shown in Tabk 3-]9.

TABLE 3-19

- NO

### x Emission Control Technology and Rate Recommended as BACT for Milton 

### R. Young Slation Unit 

### 2

Control Technolor:rv and Emission Rate Recommended as BACT 12-Month Rolling Average Unit Pollutant BACT Control Method BACT NOli**Emis~~on** 

### Rate (lbfmmBtu Selective Non-Catalytio 

### 2 NO, 

### Rcduclion with Advanced 0.J30 Separated Ovcrfrre Air (ASOFA)

3.5.2 EMiSSION RATE LIMITATION RECOMMENDATION To complete the BACT detenmnation process, the Consenl Decree (CD) reqwircs that "specific control lechnologies to be**installe~** 

### and a specific Phase 

### II**~O-day** 

### RollingAverage NO

### x Emission Rate limitulion (lbsIMMBtu)"Jl (pounds per million Btu) mustbe e.slablirned for each subjcct emission Unit.. TIle CD also siates that "a "3D-day Rolling Average Emission RatO" "hall be determined by calculating an arithmetic average ofall hourly emis.sion rates in Ibs/MMBtu for the**~urrenl** 

### Operating Day**an~** 

### thc previous 29 Op=ting Days. A new**~I)..day** 

### Rolling Average Emission Rale shall be calcwluted [or each new Operaling Day. Each 3D-dayRolling**Averag;~** 

### Emission Rate shall include startup, shutdown. and Malfunction periods wiIhin euch Operating Day',]'.

}] Ibid footnote number I, 

### Paragraph66. 

### p.ge 20.

" Ibid footnole number I, 

### Paragraph 5, 

### page 4. Square Autte 

### Electric COOP"",tivo Bums & 

### MoDoonellBACI'An.lysis [orMRY S\.alion Unil2 NOx Emissions NOx BACT An.lysis Smdy



# • The ConsentDecree also states lhat the North Dakota Department ofHeallll's (NDDH) No" 

### ''BACTDelermination shall address specific emission limitalions during Unit startups"" alMilton 

### R_ Young**Sla~on_** The type and durntion offuing during startnps, and the limited ability of available and fe.sible technologies to control startnp NO

### x emissions, bolh significantly influence Ihe 30-d.yrolling overage BACTNOx emissionr.le limit recommended forMillon 

### R. Young Stalion boilers_ A 24-hourrolling average NOx emission rale limit applied to startllp pcriods is also recommended [orMilton R. Young Station boilers.

The Consenl Decree and 

### the EPA's NSR Mauual donoldcscribc 

### the method fordetennining a 30- day Romng AverageNO

### xEmission Rate permit Iimitalion (CD Ph..,e II) lhatrefleels BACT applied

### to Millon

### R_ Young Slalion Unit 

### 2_

In keeping with the establishmenl ofa speoific 

### CD Phase 

### II 30-day Rolling

### Average NO

### x Emission Rate limitation, a relevant preeontrol baseline level ofemissions and its basis mllst be determined

.



### . -,,:The EPA's NSR

### Manual states: 'The baseline emissiollsratc rcprescnlS a realistic sccuario ofupper boundary uncontrolled emissions 

### from the sour<:c. The NSPSJNESHAP requirements 

### or the applicalion ofcontrols, including other controls neoessary 10 comply wilh Slate or 10001 airpollutionregulations, 

### are nat considered in calaulating thebaseline emissions. In other words, baseline emissions 

### are essentially uncontrolled emissions, calculated using**reaJis~c** upperboundary operating**a~smuptions"J4.**
Also slaled in the EPA's NSRManUllJ: ''Estimating realistic upperbound 

### case scenario does not mean that the source operates in an absolute worst-case mannCI all the time. For examplc, in developing a realistic upper boundary case, baseline emissions calculations can also considerinherent physical or operational constrnints onthe source. Such constrainls should accuralely reflect Ihetrue upper boundary ofIhe source's .bility to physically operate and lhe applicunl should submildocumenlalion 10 verilY these constraints"".

"Ibid r""toole numbor I, Paragrapb 66, page 20_

" Ibid foolnole uumbor2, NSR M3rnJIl1 pago B.37 "Ibid foelnole numbor2, NSR MlUIual pago 8.37. BllTIIS & McDonneU Square BUlle me<tric CooperaliveNOx BACfAnalysis Silldy BACTAnalysis for MRY SlationUnil2 NOx Emissions

The 13ACT Analysis was conduded based upon the highcsl histOlical 12-monlh rolling NOx emission summalion opcraling condilions forMilton R.. 

### YOUllg- Sl.liunImikr" during years 2001- 2005. However, n bnsdine relle<:ting a realistic upperbound case scenario based upon the highest hislorical 3D-day rolling NOx emission operaling conditions during years 2001-2005 was cSl.blished prior 10 recommending enforceable permit**condi~ons** for BACT I" be applied 10 each Millon 

### R_ Young Slalion boiler.

The approach taken in Ihis**an~lysis** was to idmtify pre-mntrol 30_day baseline operoting conditions from lhe 3D-consecutive day period with lhe higheslhistoric unilNOx mass emissions (pounds) n..-ported for actual operation hetween January I, 2001 and Deoember 3l, 2005_ TIllS reflects unil NOx emission, lh"t were b'CIlernkd duringperiods ofhigh ullit operalions, nol "ffcclcd by unit shuldowna,**s~,rtups,** or malfullctions_ MRYS Unit 2's**high~,l** reported 3D-day rolling avernge NOx unil emission rate during year, 2001-2005 was 0.874 Ib/mmBtu forilie period ending Apnl5, 

### 2002. The corresponding MRYS Unit 2 30-day average hourlyNOx mass emission mtc was 3,726Ibfhr. Thc**aV~"Tage** unit heat input rate torMRYS Unil2 was 4,264 rrunHtu!hr, and the average gross unit electrical power oulputwns 450.2 

### MW, for the same JO-<lay period.

The**opera~ng condi~on,**  during lhe highcst hislorical 3D-day roning NOx emission for yc.rs 2001- 2005 were lhen compared (0 lhe highest l2-monlh hiSlorie pre-conlrol baseline conditions. The**aV~TJgc** unit NOx emission rate (lbfmmBtu) from the highest historic pre--control 3D_daybaseline period was compared wim lhe**avcr~gc** NO" emission rale (lb1mmBlIl) from the 12--consccutivc month period wilh the highesthisloric unit NO

### x mass emissions (pounds) reported for actual operation during the same 5-year look-back period. 

### An eslim.tc ofNOx emission reduction for lhe proposed 

### BACT NOx allemalive opernting al thc histuric pre--col1trol JO_day bnseline average NOx emission rnte (lblmmBtu) was made. This rale considered recognized operntional faelors al1d equipmenl designs nppliod to "sleady stale" condition, wilh sust.med outpul close to maximum conlinuous capacity ralings.. The polonlial impact ofstartups, recognizing operolionul amlleclmical limitations on NO

### x emission control performance, was lhen applied 10 the steady-slate rate, 10 eSlabliah a rcc"nunended 30-day RoJling Average NOx Emission Rate permit limitati"n (CD Phase U) lhat reflccts 

### BACf forMilton R. Young Slation Unil2. This is explained below_

NOx emissions for cyclone-fired boilers are typically higher in poundspcrmillion BTUs during start up event, than during slc;uly"slate operntion at maximwn eonlinuous rating (MeR) conditions.**Thi~** is bee.usc hourly heal and combustion airinpulrulea reqnired to eslablish adequate molten .".

SqUllTC Butte Electrie CAopemtive 3-42 Burn' & McDonnellBACfAn.ly,is fo,-MRYSlalioD Unit 2 NOxEIni

..ions NOxBACfAn.lysis Srudy
slag [ormation wiLhin the cydonebarrels and promote slag tapping lire typicallyproduced from firing conditions tha( createhigh flame temperatures. NOx emissions lire sensitive topeakfurnace gas temperatures, IhllS uncontrolledNOx emissions canbe high during cydone boiler startups. Furnaoe exit flue gas temperatures (FEGTs) during oyclone boiler startups are less than those occurring during conditions ofsteady slate 

### MeR firingrares due to lhe high heat absorption oflhe boilermetal and 

### waterbeing raised 

### from ambient or nf':llr-ambient temperaLurCS. Until sufficient FEGT exists fora feasible and availablepost-combustion lcchnology, such as SNCR, tobe cITeclive, NOx emissions will be basically uncontrolled. There is a praclicallower limit ofboilcr heat input [orconventional combusLion-basedNO

### x emission coutrol lcchniques, SUGh as the advanced ven.ion ofseparaled overnre air, to be operaledbeyond the amounlrcquired for (;{Joling the SOFA injeotion nozzles when it can be diverted from lhG cycloneburners and significantly control NOx emissions. These limitalions ofthe effectiveness ofBACfcontrols on Millon 

### R. Young Slalionboilers during slartups and otherreduoed-load operatingperiods influenc:e the reoommended 24-hour aud 30-dayrolJing averageNOx emission rate limits.
'OSlartup prooednres for sleam elcetric generating units (SEGUs) oomprising a fossil fuel-fired boiler

and steam lurbinc-g.:neralor are specified by lhe original equipmenl nmnufncLurers to follow guidelines forheaL and pressure inoreases Lo provideprotection ofloiler and turbine equipment.

--**Inj~al** slartup duration after lin oUblge may be dictlted by the n""d 10 gradually warm up burner

por1lcyelonerefractorymalerials, steam drum shell, sLeam headers. amI otherboiler metal surfaoes exposed dirceLly or indirecLly Lo furnace g;lSCS, and !he sleamturbine's multiple casings androtor shafts. This is uormally accomplishedwith easy-lo-ignite fossil 

### fuel firing (such

### as natuml gas, distillate fuel oil, or propaue) oftheboiler combined with coal 10 gmduaJly increase .firinguntil reoommended boiler steam outlellemperature and pressure arereaohed, This is followed by supplying Lhe steam turbine with wflioicnt inletslearn flow to reneh condilions lhat allow the coupled generator to be synchronized ami electricity tobe generated above 

### zero megawatts. From this point, boiler 

### fuel fIriug is increased within prescribedroles until the desired operaling load is achieved,

The SEGU startup operatillgperiod is usually lIot defined in emissionpermits. Startup is lhe period beginning withinitiation of

### LUel ignition, amI**cantinui~g** unLil the powerplaul equipmenthas r.achcd operaling conditions Lbal include continuous fuel firing und sustained operating sleom pressure and temperalure levels withill the guidelines o[ the designs for the boiler and turbine and lheir auxiliary sysLems for miuimum sustainable levels wilhOUt causing damage 10 the equipment

Burns & McDonnell SquaTe BUlle Elecrrie**Coopern~ve**NOxBAcrAnalysis Sn1dy BACT Anolys,s fuTMRY S!nllon Uuil2 NUx Emissions

A recent SEGU pwposcJ PSD permit has induded 

### udefinition ofstartup a5**'~he** period beginning 

### with ignilion and lasLing until Lhc equipment has reached a continuolL" operating level and operating permit limits"". Similorly, a shutdoWllis defiued os '1he period beginning with the lowering of equipment fTom base load and lasting until fuel is no longer added to the boilerand oombllstion hus oea.,ed,,17.**Bas~d** on lhe reterenced defmitions ofa startup period and a "huldown period, lhe amount oflime required for a SEGU's load (boiler steam output or generalor electrical output) 

### to increase beyond such minimum ,uslainablc opcmLmg levels ca'i be considered pilrt ofslaltup**~vents** iflhc SEGU is typicallybase-lo.ded al full load orMCR OlltpUt. This is the case with bolh MRY Slation SEGUs.
Startups ofl'lEGUs m"y be labeled as cold, wann, and hot to accounl for lhe amount ofresidual lleat remaining in the boiler and steam Lurbine equipment. The vurious typC" ofstarts are depemlenl upon !he amounl oftime 'he SEGUh.s been out-of-servicc**(i.~.** wilhoutboiler fuel**~ring** Or**~enerator** megaw"lL output). Cold "tarts have been dcfiued as start, after thc boilerhas been withoul fuel firing formore lhan 72 hours, warm slarts are more lhan 8 hours and less than 72 hour", and hot starts arc Icss Lhun 8 hours"_
Allhough the definition ofa**s~rtllp** event and the corresponding "tartup period is nOl rC'JuiTed by the Consent Decree, defining slart-ups is recommended. This help' 10 uddrcss!he speeifio emission limitalions dllring Unit ,tartups al :Millon R. Young Station aud determine the Impact ofsuoh upcmlions on 30-dayrolling**av~"[age** NUx emissions. For lhe purpose ofthis NOx BACT analysis,
a Unit startup was defmed as the period from initial fuel combusLion 

### 10 the point in**~me** when;

• lhe measured Heatlnpullo U,eboiler On a 6-hourroJling average ba"is is greaterthan or equal 

### 104800 million BTIJibr for Unit 2; or

• !he amount ofLime reported for the longesL individual Unit 2 slal1up period during actual operation between J3Iluary I, 200laud Th,'"Cember ) I, 2005**cl~p"e",** whiohever ocours first; or

• fuellirillg is disconliuued priorto satisfying ei!herprevious criteria.

This sl>lTlup definition for ]VlRY SlatilHL Unit 2 accounLs for coudilions where cyclouercfraotory materials replaced during hailer overhauls must be oured by extended low-firing heating eyclcs,

." De,erL Rock Energy Cente!' (AZP04-01) ProprrsedPSD PenniL Conditions, page 7. Ilmp"fwww_CJ1:Lgovfregiou09/.iTfpermitlde,ertrock/#pennitj

, lbiu, pago 7.

" Applioation [orPreventionofSignir,eonl De1el'ioralionPenrrit rorlh. DeSe11 Rock Energy Facilily,

DocomcnlNumber 09417_360_250Rl, May 2004, page 5_1. Squ,reDUlle Electric Cooperative 3-44 Bums & McDonndlBACT Analysis [orMRY S",lion Unit2 NOx Emissions NOx BACTAnalysis Study



# ,-



# , unil conlrols arc upgraded md musl be adjusted during low-load operation, or forboiler feedwater quality to improve after boiler maintenance 

### has been perfonnedthaI aITecls the insides ofthe wale"",,]] and superheated sleam tubes. 

### II also**allow~** [or a failed or interrupted start sequence which canrequire considerably loss orruore lime to elapse lhan an average slartup duration.
Analysis or:MRY StalionUnit 2 operations data from 2001 through 2005 rev""led:

• There were 62 tolal startups in the five yearperiod;

• Minimum startup 

### waS 14 hours for a "hoI" start following a boilermaster fuel iUlerruption (Unit "trip");

• Maximum startup with an exlended ramp-up period lllltil full load was reached was 115 hours.

Unit 2 had a start-up thaI began on O<:lober 25, 20011hallasled for 115 hours. This Startup included initial firing inthe 20'" hour of 10/25 (2000 hours being the beginuiug oflhe st>rrtup period), aud which ended allhe end ofthe 14"'hour (i.e. at 1500 hours) on October 30, 2001, upon reaching451 

### MW (gross) outpuL The criteria ofa 6-hour average heut inputrate ofmOre 

### Iban 4800 million 

### Btu perhourwas not reuched during this startup
.

. There are certain boiler operating condilions thaI need

### to exist before theBACT NOx control techniqucs and technologies caube effectively opcralc<l:

1. The furnace gas tempemture in theregion where a urea reagent solulion is injected for SNCR_basedNOx control mustbe between 1700"F and 2100"1'. This region is expected to be in the vicinity ofthe furnace exil, which is commonly defined as cilher thehorizontal plane cxtending from thc furnace rear wall arch (''nose') 

### to lhe front wall ofthe boiler, or the vertical plaue from the nose up to lhe furnace roof, upstream ofthe gas inlet to the superheater tube banks. The 

### gas temperature (FEGT) range in this furnace region is dependent on boiler heatinput rate and cleanliness ofthe firesidcs oflhe furnace walls, which alTects the lITnounl ofradianl energy absorbed by the wall tubes and transferred 10 the waterwithin. 2. The numbers oractive cydones and continuous coal firingmles must be enough 10 establish sufficient
a. coverage ofmollen slag on the actively-fired cyclone barrel surfaces and drainage of the slag from the bollom o[(he boiler; and

Burns & McDonnell Square Bultc Electric Coopcrati\'eNOxBACTAnalysis SluJy BACT Analysis [orJl,fRY Station Unil2NOx E!ni,simL'

b. combuslion airflow through the actively_fIred cyclones 10 allow a portiou to be diverted to lhe**S~'JlaI"Jled** overfire air system above !he amountrequired foridlc cyclone cooling and SOFA n02:7.le cooling.

As previously discussed,**fiIm~ee** exit flllc gas temperature' (FEGTs) will need 10 be measurcd or delermined empirically during operation oflhe MRY Station boikrs 

### in order 10 be able to**~IT~cLively** control NOx emissions using SNCR Lcehnology. The design and operation ofthe SNCR systems al MRYS for CD Phase 11 emissions control should inclUde features thai accormnodate cyclone boiler startups and low-load operalion wilh "ClcilIl" or "dirty" boiler heat transfer S"'faccs
as soon as conditions occur**lh~l** are lcclmicallypraclicable, i.e. within the SNCR syslcm vendor's

. rccolIllllended operaling guidelines, as well as fulJ.load eondilions in orderto minimize**NO~** eJlllSSIOns.

The amounl aud duration ofsustainedboiler heat inpuLreqllired 10 e,o;lablish 

### the operating conditions described in item 2 above is more difficult to precisely delermlne. Lignile heal content varinbilily and inability to accuralely detennine the actual nirlfllclralio on a cyclone-by-cyclone b1lsis inreal-lime, and the slagging and fouling chHmctcristics oflhe lignite ash, cause (and arC expecled [0 conlinllc 10 c"use) difficulties with stable coLnbustion performance. The minimum firing ralos oflhe MllY Slalion boilers required 10 suecr;>sfully iniliale lhe effective operaUon oflhe SOFA sy.'lem are specifIc to each individual boiler, and are not eUlTentlylmoWD.**D"~** 10 such operating problem, and emission control limitations, the ability 

### w**cfI~clivdy** limit NO, emissions during startup periods and low-load operaLion following implerrumtation ofadvanced SOFA (CD Phase I control) and/or an SNCR sysLem (CD Phasc II control) is uncertain.

Because lhOle arc expected 10 be minor short term variations in opemting condllions during startups where Mirmkola has nol, in**fac~** malerially changed any oftheir nOllllilJ startup opel'lting praclices and criteria, a margin belwCCJI [he 30-day rolling average sleady-sLate NOx emission rale (which docs not include the impacts ofstartups) and Lhe propo!cd 30-<iayrolling averageNOx emission pennit limit lhat includes startup cmi,sions is recolIllllended.. This rote**consid~TCd r~...,ognized**  operalional13ctors and equipmentdesigns**~pplicd** Lo steady state conditions with sustained oUfput close to rna'limum continuous capacity ralings. The recOlIllllcndcd 30-d"y Rolling Avemge NOx Emission Rale permit limitation excluding the impael o[,larlups thai refleels BACT fm Milton R. Young SLatiou Unit 2 is sho"n in the table below.

Square Butle Electric Coopemlive Burns & McDoIlJlcliBACT Analysis for MRY Slol100 UlIit2**NO~** Emissions NOx BACTAnaly'is Slndy



# 1 TABLE 3·20 - Recommended 

### NOx BACT Control Method and 3D-Day Rolling Average 

### NO" Emission Rale Limit Without startups JO-day Rolling Average 

### NOx Unit Pollutant Control Method Emission Rate Limit Excluding startups (Iblmillion Btu) Selective Non-ealalytic 

# , N"" Reduction with Advanced 0.350 Se araledOver1rrc-

### Air fASOFA)

ThIs recommended BACf30-day NOx emissionrale limit is bastxlllPon a hislorio pre-control 30- day baseline average NO" emissionrale ofO_8741blmmBlu for Unit 2_ Thebaseline emission was determined from the JO-consccutive dayperiod with the highest historic unit 

### No", emi.-sions "'Ie reporled for actual operation belWeen Jau\llU1' 1,2001 and December 31, 2005_

ArecommendedBACf30-day

### NOx emission rate limillhat includes the impact ofstartup**~')lis5Ions** should be suitably higher suoh that operation oonsislentwilh lhe lechnological limitations, manufaoturer's specificalIoru;, and good engineering and maintenance practices to the extent praclicable for the 

### MRY Stalion boilers would not resnlt in an excecclance (violation) of

### an enror".able JO-day rolling average NOx emissionpermit limit.

Eor MRYS Unit 2, lhe recommended 30-dayrolling average NOx emission permit limit rate lhat indudes the impact ofslartups is bosed 

### upon recognized operalional fadors and equipmenldesigns that influencewhetherthe startup emissions r","ult in higher 30-day emissions compared 10 normal oontinuous operation wilhout or excluding such startup pcriods: 

### L The uncontrolled emission rate (i_e. wilhout sepuraled OFA or SNCR in operation) andits variability during operation from a cold, worm, or hot 

### startup up to and indurling=imum cotJIinuollS

### rated**outpu~,** 2. Thc operaling conditions lhat are required lo cXisl for lhe selccted NOx BACfconlrol teclmiqucs 10 be initialed and be ei1i:ctive; and 3_ 

### The effectiveness ofthese two pnrticlliar control techniqucs ifinvoked at less_lhan_MCR steady-Slale operating 

### condllion>. 4_ Thenumber o[startups and their range oftypical durations per 30-<!ay period lime frame.

Burns & McDcnnell J·47 Square Butte Eleclric CooperativeNOx BACT Analy<i, SLlIdy Rev;.,od I(lIII/200l> F1ACr A""lyo!' lul' MRY S'alion lJn" 2 NOx**~mi."io"" Th~**  Oe(obe[ 25-30, 2001 stnrlup 

### \Va.' chosen fDr addilional evaluation a.'**Ih~** Slnrt.up for MRY SI1l1ion Unit 2.

An incremental adjustment 10 the propo,ed ,10.day rolling**"v~mg~** stcady-<mtc unit NOx llACT emi,,-,ion Me without slJrtups of0.]5 lbimmlllu ror Unit2 i, recommended for**th~** 30-d"y rolling avemgc NO, emi,;""n pcnnillimit peri"Js JS defined and applieJ to Millon R. Yout\g SI"lion. This is snmmarized in the lable bduw_

TABLE :l-21

- Recommended BACT :lO-Day Rolling Average NOx Emission Rate Limit and Startup Impact 30-day Rolling Average NOx Impact on 3D-day Rolling Unit Emission Rate Limit Average NOx Emission Rate, ExcludIng Startups Limit Due to Startups (Ib/million Btu) (lb/million Btu) 

# , 0.350 IO. I02 pcr SLa'lUp

Thl>**re~olTllTlended adjllstm~llt**  TO lhe pfOpo,cd 30.day wUing ,"vemge ,teady-mue NOx DACT emission rate limilwithoUl slartups is based**u~on** overage historic pre-control NO., cmis.,iGn rotc< ot· 0,959 Ib/mLl18Lu for Unil ! reporlcd for the longe,' lIldindual lIltil 2 sULrlup period during actual ope"'t;on between January 1,200 I and December 31, 2005.**Thes~** emi.«io".' ,"ceurn:(1 during lile liS-hom Oclober 25-30, 2001 startup For lJ"il 2.

A 24-hour rolling average BACT NOx emi,<iun note limit applJcd to Sl;lrlLlp pe,iod, i, a[su ,",commended for each of**[h~** ",Iill"" R. Y"ung St"lioll boilers. Thi.' i.' <ulIlLt""izc,,1 in the Ltlblo below.

TABLE 3-22

- Recommended 24-Hour Rolling Average NOx Emission Rate limit During Startups
24·hour Rolling Average NOx 

### Unit Emission Rate Limit During Startups (Iblmillhm Btu) 

# , 1.06'1 

## :3 3



# , 

# ",

Square**[IUlI~** Eicclric C"0p"cJli, e Gums & !cicDolladlBAC[

### Analysis [orMRYSlationUnit2 NO" Emi""ions NO" BACT Analysis Srudy

These emissions occurred during lire li5-hour October 25-30, 2001 startup forUnit 2.
Compliance with lhese emission 

### rotes would

### be measured at the slack oflhe**Uni~** 

### verified with 

### Conlinuous Emission Moniloring(CEM) syslems in acoordance with 

### !he reference methods specified in**~O** 

### Cl'.R- Part 

### 75, and wonld be determined 

### 00 a 30 consecutive OperalingDay and 24-consecutive hourrolling average basis, respectively.

A lrial 

### demonslration operatingperiod of 18 

### months aller lhe completion ofCoosenlDccrce Phase II NO" 

### emissionrc<1uclion system installatiou commissioning atMilton R. Y

### oUllg Slation is recommended. It 

### is proposed to allow MinnkOla (for Square Butte) to demonstrate the actual control system oapabilities oflhe combinedNO" 

### BACT emissions reduction syslem. Op=ting experience duringthe trial periodwill:

• confirm steady-slale conlrol pertbnnance ofthe combined NO" BACT 

### emissions reduction system;
..• allow delerminalion ofthe ability 10 

### furtherconlrol Unit start-up emissions;

• allow the determinalion ofthe permitted 30-dayrolJing av=ge

### No" emission limit including startups, shutdowns, and malfunctions; and

• address the specific emission limitations during 

### Unit startups al Milton R_ Young Station and their impact on the proposed 30_day rolling average emission ralC limit (withoutslartups).

Based upon lhe informationobtained during lhe trail period, fmal emission limits can then be delermined.

Themeans lhat will 

### be employed 10 

### minimize emissions during startup will 

### primarily be based on operating procedures, both before and after lhe level ofupper furnace 

### gas temperalUICs and/orheat input mle 

### are considered sufficient to slm theNOx 

### controls and operaling conditicns are conducive for effective emissions reduction_ These could be similar to 

### Minnkota's currentMRYS practices, or 

### could be different., dependingupon the capabilities ofthe NO

### xcontrols and lheirimpacls onUnit op=tions.

Burns & 

### McDonnell**;~,** SquareButteElectric Coopcrali,,,

### NUx BACT Analysis Srudy
RererenGes; BACT Analysis forMRY SWlionUnit2 NOx Emissions

1. 

### Tn the Uniled States District Court f'or 

### The District OfNorth Dakota, Uniled States Of Amerioa and State Of North Dukola, Plainliffs, 

### v_ Minn!wta Power CoopCTi1tivc, Inc. and Square Butte Electric**Cooper~tjve, De[end~nl.'l,**  

### Civil Aclion No.1 :06-CV-034.
2. 

### EPANew SourGe Review Workshop Manual, Prevenlion o[Significanl Deterioralion and Nonattainment Area Permitting, Dran Ootober 1990 

### (The "NSR Manoul")_ 3. EPA Docket OAR-ZOOZ-OU76-0446 Technical**SupportDoelJIJl~TII** 

### [orBART NUx Limits far Electric Generating Units Excel Spn;,,<Ishpcl 

### 611512005, posted on lheir website: from EDOCKE1"at**http://d''''ketepa.llov/edkpubfdoJEDKSlaffitemDetailView?objeond~090007d4B0B4S6Zb;** 

### lhis is associated with EPA Acid Rain Prol,'Tam Clean Air Markets Division,**Tcchnie~l** 

### Support**Doeum~'IlI-** 

### Melhodology For Developing 

### BART NO, Presumptive Limits, Juoe 15, 200S,OAR-Z002-0076_0445. 

### 4_ EPA Office of

### Air QUality PlaJIlling und Stundards (OAQPS) publication EPA/452iB-02-001, Seclion 4.2, NOx COlllrols- NOxPosl-Cambustion, Chapter I - 

### Selective**Non·Cataly~e** 

### Reduolioo, dated**Oclob~"r** 

### 2000. posted al lheirweh.,ile, hltp:llwww.qm,govfttn!caloldirllcs4_ 2 Gh1.pdf

Square Bulle Elcctrie ('",operative Bum., & 

### McDOItIldl

## '-'1 APPENDIX A Technical Feasibility Assessment Details for NOx Control Technologies (A1) U.S. Coal Cyclone NOll Reduction Projects Summary With Retrofit NOx Control Projects' Technical literature Summary (A2)

### APPENDIX Al Technical FeasibilityAssessment**DeIil~s** 

### for NO" Coolfol Technologie' NO"BACTAnalysis Study



## A.1 A.1.1 Technical Feasibility Assessment of 

### NOx Control Alternatives Pre-Combustion 

### Fuel Treatment/Switching Fuel switehing canbe a viable melbod ofNOx 

### emission reduclion in cerLain situations. Often, coal combustion facililics are construcled to 

### take maximum advantage

# or !he particularcombustion**characleris~cs** 

### ofa specific fuel. In 

### lhe case of:MRY Station, the Unit I and 

### 2 boilers were designed and constructed specifically for firing North Dakola lignite, whieh has a fuel higherheating value (Blullb) approximately 

### 20% lower than typical PowderRiverBasin 

### (pRB) coaL Acyclone-fired boiler (Ottertail's Big SloneUnit 1) 

### lhal is similar in geometryand steam generation design to MRY Station Unit 2 fires PRE coal. Based on a comparison ofavailable emission data between Big Stone Unit I and MRYoungUnit 

### 2, lhere is no expected reduction inbaseline (i.e. uncontrolled) NOx 

### emissions from switching loPRB from lignite at Mtlton 

### R. '{oung Station.

Conversion ofMilton 

### R. Young Station Unit 

### 2 boiler to fire PRE coal is technically possible. 

### II is expected lhat major plant modifications will bereqnired. Rail service is not presently inst<llled at this silo,
so !he addilional operational andcapital cosls to 

### bring in large quanlities ofPRB coal will 

### be significant. Investigalion ofthe specific source, distance, and costs for supplyingnecessnry**q~anti1ies** 

### ofPRB coal via 

### ,-ail or trocks to MR. 

### Young stalion has notbeen perfonned. Wilh zero 

### baseline NOx 

### Cffiissions reduclion expected from application offud 

### switching, lhis alternativewill not be economically competitive with olherNOx 

### controlleclmologies that 

### offer betlerresulls fora much lower combination of capital and operational costs. Although fuel swilching is technically**fe~sible,** 

### it has notbeen oonsidered furlhcr as on effective NOx emissions conlIol option forMRY StationUnit 

### 2 boiler.


### A.1.2 Combustion Controls Combustion controls comprise lhe most numerous categoryofNOx 

### emissionreduction technologies. These !eelmiques employ methods lhat reduce!hc amount ofNO

### x emissiollS created in !he combustion
zone oflheboilcrprior to 

### exhausting the flue gases .from lhe furnace (upslIoamoflhe convective heal transfer zones). These controls resull in fewer emissions 10 

### atmosphere or thaI 

### may require subsequent redudion from additional applicable oombustion and/orpost-combusLion teohniques.

lIB 

### !hcboilers in question were designed for firing NorthDakotaJigllite fuel, they were furnished with 

### suitably_sized furnaces and limited back-end economizerheattrnnsfersurfaces upsLream oIlhe air preh

...ters. This provides high temperature air 10 

### aid the evaporation ofexcess moisture from the crushed coal particles 

### in !heprc-<:ombuslion drying systems, and longresidence limes for solid and gaseous fuel Square 

### Bulle Elcctric Cooperativc Al-l Bums & McDonnellNOx BACTAnoly,i., StlJdy APPENDIXAl Technical F=lbilily Assossmenl Detail5 rnrNOx Contr<>lTechnologies
particles to burn essentially 10 completion priorto leaving the furnaces. The laUer feature is especially advanlageous for applying various fbrms ofcombustion modifiCillions which are oonducivc in reducing NOx emissions.


### A.1.2.1 Basic Combustion Improvements Combuslion improvements are commonly-applied leohniques which may produce modesl incremental NOx emissions reduolion•. Tn their mosl b"sic form. the.'e typically provide impl'ovemenlS 10 comhustion air flow distribulion, meaSuK'ffienl. ""d pre""ure, logethcr with fuel now measurement aud metering, to promole consis(cnl combu.lion perj'ormllIlce by burning fuel with more accuracy in mainlaining a desirctl fuel/airralio.

These improvcments may allow, 

### orhe oombined with, the**prac~cc** ofseveral otherNO

### x oontrol teohniqucs. Separaled ovcrfirc"ir (diseussed below), wilh or without "Iow exoess oir" (LEA), hUffiC'" uut-of--service (BOOS) and biased firing (BF) opcr"tion oflhe cyclom;s, .couse a decrease in**Ih~** ratio of combuslion "ir to fuel snpplied to the cyclones (burne,,,), lhus reducing the amoum ofthem,"l NOx 

### emi<s'tons produced during combustion. The aLlIount ofpotential NO

### x emission**reduc~on** achievable from these basic ledmiques is**highly-uop~71uent** on the speeilio Lypo ofliring, fuel,**a~d conditio~s**  whieh apply to the bOller(s) being reviewed.
Making lignile drying system ai[ adjustments md adding improvements to the bOllcr oombuslion conlrols and reducing comhustion air inpuls have already reduccdllncontrolled NOx emissions atMilton 

### R. Young Station Unit 2 boilerapproxim"tely 27%. 

### Further incremental improvements from additional combuslion oontrols lhal allow operation with modest amounts ofcyclone "irslaging, similar to the effccl ofa separated overfire air sysICm, are possible. Inoremental NOx emissions re(1uctions are expected from such improvementsbeing incorporaled into another feasible alternalive, suoh as separated [lverfirc aiL This allern"tive WaS not considered 

### as a sll1ntl-alonc option 

### for additional NO

### x reduction atMillon 

### R. Young Stalion for the Unit2 boiler_


### A.1.2.2 Low NOx Burners (LNB) Low NOx burners (LNBs) ofvarious designs have**be~TI** oommonly applioolo pulverized coal,lired utility and industrial boilcr>: for more than ten years. However, they

# = nol inslalled on cyclone_fired boiler._ This lec1mology is infeasible on cycloneboikrs', and was eliminalcd from considerntion for addiliOTIal NOx reduction at Milton 

### R_ Young Si<ltion Unit 2', boiler.

Hurl" & McDonnell At_2APPENDlX AI Technical**F=ib~ity** Assessmen, netails for NO" ControlTechnologies


### A.1.2.3 Separated Overfire Air (SOFA) NO" BACTAn.ly,is Study

S"l'arnted overfire air (SOFA) is ;l combustion-relatedNOx emission reduction technology frequentlyapplied wilh ond wilhoutlow NO" bumers to utility and industrial boilers for more lhan twenty five years. Separnled OverfIre Air (SOFA) is an air-staging NOx emission reduclion combustion lechnique iliat 

### is typically based on withholding 

### 15 to 

### 20 peroent oflhe loW combustionairconventionally supplied 10 lhe firing zone. 'The diverted combustion air is lheninjcoled in 

### the upperfurnace, where combustion is completed. For typical cyclone coal-fired boilers, this involves diverting approximately 

### 20 percenl ofthe secondary combustion air, forcing lhe cydones to operale fuel_rich. Starved

..i, combustion causes fewer NOx emissions to be produced.

At leastthirty nine existing cyclone-fired boilers, fIriug eastem bituminous, midwestern bitumiuous, and western subbiturniuous ("Powder River Basin") coals in unils ranging in size from 

### 50 to 

### 1150 MW, have beenretrolilted wilh commercial SOFA since 1998. A s\llIlmary ofseveral oflhe first SOFA (andrebum) retrofits to cydone-firedboilers is described in published lechnical papers',z. Cyclone boiler retrofit SOFA installations are included in lhe EPA's BART technical supportdocument' and listed laterin _,AppendixA2.

A basic form ofseparnted overfire air (SOFA) Can be applied and installed on 

### MRY Station 

### Units 2. There are polential impacls and limitations unique 10the firing ofNorthDakota lignile iu cyclone-fired

, ' boilers lhat should be recognized as part oflhis emission reduclion lechnology applicalion.
Key aspects ofsuccessfully applying llI1d opemling a separated overfire air syslem on a cyclone-frred boiler are the ability 

### to'

• Aecurnle]y measure ilie fuel healinputrate (BTUs) and combustion air inputs on a real-time, individual cyclone by cydone basis, 10 allow the ability 10 delerrnine andcontrollhe desired air/fuel ratio, especiallywhen "starved air" (i.e. swsloichiometric) combustion conditions arerequired.

• Maintain adequate mollen coal ash (slag) formalion and flow wilhin thebarrels aud slag taps.

The degree to which the cyclone furnaces 

### can be operated with 

### less lhan lheoretical (substoichiometric) combustion air directly contributes 10 less NO", fonnalion and 

### fUrtherin-furnace emission reduclion but also risks solidification oflhemollencoal ash. 

### In lhe ease of

### MitY Station 

### Unit 2 boiler, cyclone combustionmust be sufficiently air-staged to reduce NO", emissions while releasing enough hea!lo continue to melt lhe fuel**~sh** so that it flows effectively wilhin and from the cyclone burners.
Sq=re Butte Electric Cooperelive Burm & McDOJlDellNOx BACTAnaly'i., Study APPENDIX Al Technical Feasibility AssessmentDclail; for NO" ControlTeclmologies

In Ihe case ofMRY Slation boilers, there is a signifioant amount oIvariability in t1,e omnbUSlible and ash oomponents ofNorth Dakota lignite supplied from the current mine near Center, NO. Analysis ofseveral hundred "Oal feed samples Laken simultaneou.ly from multiple cyclones ofMRY Station Unit 2's**b011~T** revealed that the maximum**differen~al** ofthe lignite heating values from cyclone-to-cyclone wasjust
ovcr 

### 12% ortho overage hcaling**v~lue** orall the samples. Assuming: an**oper~ting** ease oeeurrC<! whore the maximum cyclone-to-cyclone differential heating value was for two cycloues at the opposile ends of the fud hoa! eontent rango, lherc would bc n plus 

### pr minus 6% variation in fuel heat content forcithcr of the individual cyclones from the overall average. 

### Ifthe desire<:! average cyclone air/fuel (stoichiometric) ratio was 

### 0_95 when operating with air-staged cyclones associated with separated overlire air, andthe amount ofsccomJ"ry combuslion**~ir** to eaeheyelone was equal,**lh~Te** wonlcl be 

### n s!oichiomeLrie ratio of approximately 1_0I in one cyclone and" stoichiometricratio around 

### 0.89 in another cyclone at the same lime. The modestly uir-staged**eyclon~** would produce highor than average NOx emissions. The deeply sLagcd cyclone wonld produce les" than avcrage NO,,-**~'ITli",ions** and pOloutiaJly insuffieienL amounts of heal release, and raise the riskofsolidifying the fuel ash so that it accumulates within the cyclone 

### 00rre1. This coold TCsull in firing auxili"T)' fuel 011 in Lhe**decply-st~gcd** eyclonc Or taking the boiler out-of-service to remove the pluggage. Neither ofthese conditions is desirable becanse they result in lower emis.,ions removal pcrforrrumce amI highcr operaling costs. Thus, due to the variabiliry ofLho fuel heatconlent and lhe complex behavior oflignite ash when exposed to high temperatures, the extenl ofair-slaging and thus lhe level ofNOx control in MRY Slation boilers 

### is expected lo be modesl while firing lignite coals.

Jn order 10 potenlially achieve lowerNO

### x emissiou rates with modestly air-staged combustion forMRY Station boilers, additional combustion improvements can be installed. One pOlential improvemenl is 

### to Implement a unique form ofSOl'A for North Dakota_lignile-fired cycloneboilers. This Inoludes reloc:ated lignile drying syslem venlports, and inUnit 2's C"se. also involves blocked or relocated lower furnace fine gas recirculalionports. This 

### will be referred to as "Advanced SOFA" (ASOFA). 'There are severnl design challenges antioipaled for implementing the advanced version (with the described port reloWilioru;) ofseparated 

### Ol'A. These are believed lo be solvable_

Both forms ofsepnmlC<! ovcrfire air us a combuslion-reMed NOx controllcchniqne arc eon>ridered feasible for application to MllLon 

### R Young StaLion eyclone builcrB. Since Lhe advancecl SOFA is the highest-performiug form oflhis lechnology, only lhis ASOFA version ofthe alternative W"S considered for additional NOx reduetion at Milton 

### R. Young Stalionboiler,.

Bum, & McDonnell Square lllllteElectric CooperativeAPPENDIX Al Technical FeasibililyAs,<ssmenlDelalls for NOx ControlTechnologies**NO~** BACT An.lysis Srudy

Another fonn ofseparated overfire uirbeing marketed commercially is "Rotating Opposed Fire Air" (ROFA). For utility applications in the United States, lhis has onlybeen applied to pulverized coal-fired boilers, primarily tangentially-fired lIDits<. It is different than basic SOFA in that 

### it includes a hot air booster fau, aud iujecls the ovemre air in an offset fashion from opposite sid"" ofthe furnace athigh velocities, withmulti-poriuozzles located athigh elevations relative to the top burnerrow. The vendor (Moholec USA) clairru; ROFA maximizes air-staged in_furnaoe combustionNOll reduction while minimizing-negative impacts on osmon monoxide. and llyash unhurned carbon.

While this variation ofseparamd ovcrfire air could potentiallybe applicable 

### to cyclone boilers, it has not been marketed to serve such spplic.tions. Because cyclonebcilers do uotrequire the addition ofhot air booster fans for SOFA, this tedmique is not distinct enough frombasic SOFA from functional and airstaged qdone NOxreductiouperformance standpoinls to wammtindividual consideration. ROFA technology lacks demonstrated cyclonc-fired boiler experience, and thus was considered infeasible and not included in the control effectiveness amI cost_effectiveness sections ofthemain report.


### A.1.24 Oxygen_Enhanced Combustion A supplier ofliquld oxygen (praxair) has developed a method ofreplaoing some ofthe combustion air suppliedto the burners with pureoxygen_ Combustion 

### air, which is nonnally input through the sccond:lry 

### airsystem**du~twork** downstreamofthe forced draft (FD) fan and air**h~ater,** is supplemented withpure ollygen directly injected into the burners. Oxygen-enhanced combustion (OEC) canreduoe boiler NO

### x emissions resulting from" therm.1 NOx", areaction ofthe nitrogen in the combustion air admitted to the burners with the available oxygen in the air in the flame orpealetemporalure regions ofthe fuel rombustionprocess, The use ofpure oxygen mst
...d ofairreduces the availability ofnitrogen from the air to be oxidized in 

### the high lCmpermure regions, thus reducing formation ofthennal NOx. This lechnlquehas only been demonstrated in a boiler withpulverized fuel burners firing bituminous coal'.

The lack ofadequate expericnce on any qclone-fired coal-burning boiler, on a lemporarydemonslnltion
orpermanent full-scale basis, and for a coal-fired facility ofthis size, precludes consideration ofoxygenenhanoed**~ombustion** at:MRY Station Unit2's boiler. This is deemed to be infeasible technology at this locution at the present time.

Squ.re Butte EloclricCoop=tive AI_5 Burns & McDonnell

### NOx BACTAn,lysis Sluuy APPENDIX AI 

### Technical F""sibility Assessmenl DelaHs forNO,,- ConlmlTechnologies


### A.1.2.5 Flue Gas Recirculation Flue gas recirculation (FOR) bas been wmmonly applied to wal-fired boilers, primarily \0 inject inlo lbe lower fumaoe,**j~t** 

### abovo lbe burners, supplied from the boiler's economizer nue gas olltlet via a hot gas Imoster fan. Tbis modifies the amount and temperalure ofhot furnace gas eilner in lhc lower-middle Or upper fumace and convection heat transfer zones. As this nue gas typically haS"n oxygen conlenlaround 2-5%, illimits the availability o[oxygen in a high temperature, possibly fuel-rioh lower Iltmace zone. Flue g"S recirculation [orNOx control is mOst cO!Jlll1only applied with gaseous or liquid fos"il fucls to reduce the high lemperatures which convert nitrogen 

### in the combustion air to nitrogen oxides. No examples ofusing or installing FOR On cyclone-firedhoil= striclly for NOx emissions control werc [Olmd in available tcchnicalliteraturc.

FOR**i~** 

### .Iready pracliced ntMRY Station in lhe Unit 2 boiler, primarily forfurnncc gas lemperature lint! lowerwall slaggingreduction re.asOns. For this boiler, FOR could aid in potentially providing some small additional NOx emissions control ifit were modifie<1.from its current confignfJtion,**n~** 

### part ofan advunoed fonn ofsep"mlcd ovemre air. Complete elimination ofthe**~e** 

### ofFOR could ahm slightly reduce NOx emis"iQJl5 fiOin Unit 2' s boiler during air-slaged cyclone combustion with s(-parated overfire air system operalioll. There is lUlcertainty whether eliminalion of

### the use ofFGR in the lower furnace of 

### :MRY Stalion'sUnil 2 boiler could be sllcoe,.,ful in conlrolling lower furnace wall fireside ash depo,ilion

_ 

### A.1.2.6 Water/Steam Injection (Combustion Tempering) When applied 10 older gas-fired and oiI,fired ulilily .nd industriallmilers, walerand/or sleam injection adds moislure into lhe lower furnace, COllourrent with or near (to the side or slighlly above) lhe burners, supplied from the boiler's trealed feodwater or auxiliary Sleam syslems via a metering pump or valve_ Therehas**be~."** 

### some limited lesling ofwater injeclion for NOx emis,o;ions conlrol on nnturnl gas-fired and coal-tired cyclone Imilers"'. For roal-fired eydunes. lhis lechnique is most effective onhOllers burning biluminous coal; howcver, ithas not been permanently irullalled and eonlinuously opcralc<1 

### in such applications. Successfullong-lcrm operatjon ofwater injection would be difficult for lignite-fired oyclonc boil=. dne to 

### lhe bigh moisture levels in lhe coal and lhe need 

### to**re~dily** 

### ignile and suslnin stable combustion and molten sIng [onnation 

### in the cyclone furnaoes. For these reasons, waler/steam injeotion is considered leohnicnlly infeasible for NOx control applicalion al Millon R. Young Station. ..

# ,..

Bum, &McDonndl SqurlTeBunoEloctricCooptTati,e

### APPENDIXAl TechnicalFeasibili<yAssessmentDo,"ilsfor NOx ControlTechnologies


### A.1.2.7 Fuel Reburn NOxBACfAnalysis Study

Another combustion teohnology that maybe applicable to control NOx emissions from the Milton 

### R. Young Stalion unil. is fuel reburn. 

### In 

### a similarmanner thatoverfire airdiverts 

### aportion orthc combustion 

### airinpullo themain firing zone, the reburning process involves supplying a portion ofthe fuel heat input 10 

### the boiler ala higher elevation in lhe furnace. This creates !Ill 

### upper furnace atmosphere where lhe rebum fuel's**~mbustion** 

### products causes some ofthe NO" fonned in the main bumer combustiou zOnc u.od rebum zone to be converted,inlo moleculm-nitrogen. Depending on the amount of reburn fuel added and lhe amount o[oxygen available in the furnace gases to 

### combine with the reburn fuel introduced, addilional combustion airmay be supplied as 

### supplemental or overfire air. DO"ffistream ofthe air injection clcvulion, the intention is to complele lhe reaction of

### any remaining carbon monoxide (CO) to 

### carbon dioxide (CO,), plus reduce the amount ofcornbuslible maUerremaining in the entrained .flyash.

The most common forms ofreburn technology applied 10 

### ulility powerplant boilers arc:

• Pulverized ormicronized coal reburn (PCR or MiCR); and 

# .. ,.


### • Gas reburn (GR).

Pulverized coal reburning !IIldmicronized coal rebnminghavebeen applied topulverized**~a1** 

### and cycloue-fired boilers. No" reduclion effieienClcs of

### 50 to 

### 60peroent have been demonstrnted on castern ·bituminous coal andmidwestern bituminous and Powder River Basin (pRB) 

### western subbituminons coals while supplyingup to 

### approxiJIDltely 

### 20--30% ofthe boiler's total fuel heat input to the reburn zone'·'.

For utility powerpmnt boiler applications, naturnl gas 

### has been utilized as reborn fuel mostoften, demonstraled in two basic approache.:

• Conventional 

### gas rebum (CGR); and

• Fuel-lean gos reborn (FLGR"").

Eilhernatural 

### gas Orpulverized coal (lignite) cm be used 

### as the reburn fuel. 

### A sufficient qmmtityof natural gas is not currentlyavailable at the 

### Millon R Young Stationplant sileo Supplying enoughnatural gas to provide 

### I'> to 

### 25% ofthe total heat input to either or both boilers atMRY Station is cxpeeted

### tobc technically feasible, although trnnsport pipeline instanalion capit:ll costs, and current and predicted nnit natural gas costs and 

### opCTating economics, are likely 10 

### be unfavorable.

Square Bulle 

### Eleclric Coop=tive 

### Burns & 

### McDonruollNOx BACT An.lysi, Sludy APPEND[X A[ Teclmical FeasibiUry A,sessmentDe[.il, for NOx COlllrolTechnologies

Various forms offuel rebuming have been demonstrated and operated routinely on "Ydone boilers for NOx emission conlrols. This has been applied [0 unil_ firing eastern bituminons coal, and western "ubbilUminollS 

### orPRBlbltuminous coal blends, usingpulveriz.d or mieromzed eoal or natural gas 

### as the most common rebum fueL Rebuming for NOx emissions reductionhas notheen demorutrnted on a unit firing high moislure, low h",,[ content North Dakota ligllite. Pulverized/micronized coal, along: with oonventional and fuel lean gas Tcburn lcclmologies, are discwsed below_


### A.1.2.7.1 Coal Reburn In [he case ofapplying conventional coal rebum to cycloneboilers, the**exis~ng** eycloncs are supplied with the majority ofthe fuel, with either natural gus Or pulverizcd coal (lignite) ll.,ed as the rebum fuel sueh [hat the towl hentinpUIto the boiler is essentially [he same as without fucl rcbuITI_ Separnted 

### OrA ports are located above the rebum fuel injection section ofthe furnace. '1hese SOFAporls provide sufficIent oxygen in a**conven~onal** fuel rehurn installalion lO complete the combustion proce"" [hat begins in the Irnlin combuSlion zone and is supplemen[ed in the reburn and burnoul zones. TIlis is shown schema[ically for a pulverized coal reburn upplicalion On a cyclone_fired boiler with SOFA in Figure A_I1.

### Fi~lIre A,I-I Pulvcrized Coal 

### Rebllrn Application 011 

### Cyclone Boilcr

### Witb Overfire Airs

BURNOUT

ZONE ElECTRoSTAllC PRECiPITATOR 

# ,- 

# '" PREHEIITER
ECONllJIRY 

### j AIR

LTEN SLAG

REBURN



# '00' ,-- 'l i 

# - ' 

# - OVERFIRE 

# "" -.-. COAL REBURN[N(; BURNERS '_ 

# "' "-



# , PULVERIZED**---~** 

## 00" _. 

# , "'

MAlN_

____ COMBUSTION.**~,**



# " SLAG TO DISPOSAL

BmIL< & McDonnell**AI-~** Squoro BUlle Eleclric COUPLTdtiVOAPPENDIXAl Technical FeasibUiry AssessmentDetail. rOT NO" COlllrolTeclmologics NO"BACl' Analysio Study



### In lheUniled Slates, pulverized coal reburning and micronized coal reburning techniques for utility powerplantNOx emissioru; reduction havebeen applied on a verylimiled full_scale, full-time basis to cyclone-fired boilers in Geld demonstration tests and longer-term demonstration opemtion, respectively. There have been only two known pulverized or mioronized coal rebum installations in Ihe Unlled**S~lCs** on cycloneboilers, one on a utilily boiler in Wisconsin, and one On a small industrial-size cyclone boiler in Ncw York**state7~,** •.1O,11.",D."_ NO

### xemissions n;:duction efficiencies of57 percent have been demonstrated 

### on cycloneboilers firing eastern bituminous coal, 

### or midwcstern bimminous andPowder River Basin (pRB) weslern subbituminous coals while supplying up to approximalely 20-30% oflhc boiler's total fuel heat input 10 lhereburn zOnC. With the exception oflhe V_So Department ofEncrgy's (DOE) Clean Coal TechnologyProgram demonstralion 

### projects7.0", nO known eormnercially-available coal rebum syslcms have been installed and areroutinely operaled on cyclonc boilers in the United States 10 dale. TheDOE-CCTPprojects for coal reburn applied to cyclone boilers are described below.

Pulverized coal reburning for NO

### xemissioru; reduction in a cyclone-firedboilerwas demlJIlStraled on the 110 

### MWNe1son Dewey Unit2 

### for Wisconsin Power& Lighl 

### in 1991-1992. Rebum fuel preparation and 'handling, reburn burners with fluc gml recirculalion, and a separaled overfrre air syslem 

### were added. Coal reburn tests were conducted on lhis unit while firing bituminous and PRB coals. NOx emission control efficiencies of50 to 60 percent, with reductions from 0.75-0.83lbhmnBtubaseline, 10 around 0.38 :lb/mmBtu, bu{ as low 

### as 0.29 to 0.32 

### Ib/mmBtu, wilhl'RB coal at fun load with approximately 25-30% of!he lotal fuel heal inpmfromrcbum fuel were demonstrated",1I·12. The reburn systernis nO longeroperaled on Nelson DeweyUnil2.

Microni7-"d coal rebnming has 

### been demonstrated in 1997-1998, and continues 

### to operateyear_round 

### on a 

### =11 industrial cycloneboiler (400,000 

### lblhr steam oUlput, 50 

### MW gross equivalent) forEastmanKodak Company at theiT Kodak

### Park facility in Rochester, 

### NY_ This unit (Boiler

### #1 5) achieves a NOxreduotion efficiem,y ofapproximately 57 percenl on eastern bituminous coal, involving limiled cyclone air.staging (cycloncs belicved 

### to be slightly above 0% excess air) and a mouest amount ofOverfITC airinjection downstreamofthe micronized reb<IIIl fuel inputnoz:;:les_ Approximately 17% ofthe boiler's 10101 fuel heat inpm is typically suppEed to Lbe reburn wne. This coalreburn syslem continues lO operalc routinely allhis facility. This installation isreportC<! to 

### use a Fuller MioroMilllo produce micronized mal with 80% passing lhrough 

### a 325 mesh screen7,•• ,,_

SquaTe Bulle Electric Cooperative 1\1-9 Bums & McDunndl

### NOx BAcr Analy,j, Study APPENDIX At 

### Technical rca,wili!)'**A"ossm~,,'** 

### Delails for NOx ControlTeclmologies

Ifa coal rebnm system was applied (0 MRY Slation boilers, the exiSling cyclones would be supplied with the majorily oflhe fuel in the form ofcrushed ooal, and thebalance offuel would be supplied to a pair of dedicaled pulveri7..ers 1<> feed Ihe rebum i<>jection ports, such Ihal the tolal heat input 10 the boiler is cssenlially the same as without fuel reburn. In a conventional fuel rebum insl"lIation, OFA ports 10Galcd above (he reburn section ofthe fllrnacc provide sufficient oxygen 10 complele the oombust;on process that**bc~rjJlS** 

### in the mJin Gombustion zone and is supplemenled in the rebum and burnout ZOnCS.

Similar 10 the Jpplication ofseparated overfire air, Ihere are potenliallmpacls and limilutiuns uniqne to the firing ofNm1h Dakota lignite in cyclone_firedboilers !hat should be recognized as part ofthis emission reduction I.

..

### :cimology**~ppJication.** 

### As a rcbum fuel, lignile is expected 10behave appropriulely upon introduction in the lower middle furnace to help reduce NOx cmissions. Thc ConcCms ure Ihallhe diversion ofa**signiJjc~nt** 

### amount ofhcat inpul from lhc cyclone barrels to use as a SOllfGe ofrehurn fuel in the form ofpulvcnzed or micronized lignite may reduce**cyclon~ temp~ratures**  

### "l1ough lo inhibil sbg fornlalion and flow,**~specially** 

### a,**bo;l~rload** 

### is rednced_ Air-slaging: lhc cyclones with the nse of separated overlire air 

### to further complement combustion NOxreduction as part ofthis rebnm rechnique will furtherriskslag"freezing" in Ihe barrels and**low~r** 

### furnace. Re

.. lueing thc number of**;,cliv~** 

### cyclones which are air_ and fuel-slnged 10**accommoda~c** 

### Tc

..luccd firing rates while operating a**coal-fir~d** 

### boiler wilhrcburn and separnted ovedi.re air is the typical approaGh to aVOid slag lapping problems.**Pot~ntial** 

### NO"**~missions** 

### reduction performance is**exp~"Ct"d** 

### to**b~** 

### limited on lignite-fired**cyclon~** 

### boilers wilh" basic form ofseparaled overfire air syslem, sinGe Ihe rcburn fwel mjcclion localion is expecled to coincide with the existing lignite pre-<1rying system**v~nl** 

### porrs. Thc amounl ofoxygen introduced by**th~** 

### vent ports "I,ll be**disruptiv~** 

### to any conventional rebum process in that il would reqnire much higher rebum fuel 

### Injeclion r"lcs 10**~r~ale** 

### a subsloichiomelric ahnosphere in the**]ow~r** 

### secondary furnace that is couducive to 

### promoting in-furnace NOx reduction.
Signilicanl addiliom; 10 Ihe fuel preparation equipment in**Ih~ ~xisting**  

### plant**f~eihli~s** 

### will be**requir~d_** 

### The coal rcblJrn syslem expected 10**b~ appli~d**  

### 10 MRY Sialion boik7S m.y use two 

### new fine-grind pn]veri7..ers and dYllamic classifiers to aehicvc the kvel ofcoal particle size distribution require<!,
Higher unburnC<l carbon levels in Ihe ilyash exhausted from Ihe boiler muy occur, cspeciaHy when the rebum fuel is coal, andthe regularburners are fired wilh less Ihan theoretical amonnts Ofcombustion air commonlypracticed with**th~** 

### use of**ov~rfire** 

### air_**Lnw~ring** 

### (he rcb"m fuel injection elevation, decreasing

Rurru; & 

### MoDonneH Al-IO Square Butte Electric CoopcroliveAPPENDIXAl l'ecllnicalFeasibililyAssessmentDelail' for NOx Control Technologies NOx BACfAllllljl5is Study



# , lhe aJll(}unl ofrebum 

### fuel, and grinding lherebum coal to a greater degree offineness can hclp to offset
some oflbe increase in flyasn Ill1burned carbon content. Flue gas opacily from Ihe stack may increase if the particulale removal equipment 

### is**~n** cleclrmtalie precipitator, due priJrulrily 10 reduced resistivily ond smaller particlo sizes oflhe flyash.

An issue lhalaffects the feasihilily oflignite reburning is the uptime required [orthe ligniterebum fuel pUlverizing system, and impaclofthe rebum systel)l on elTecliveness in reducing NOx emissions during load changes and lower loads_ Typically, one new pulverizer is dedicated 10 preparereborn fuel in exisling pulverized fuel-fired boiler applications. Cyclones may be fired wilh less fuel ordeactivated during boiler operalion in order to accommodate chnngcs in fuel combuslion charocteristics, boilerload, and for scheduled orunscheduled individual crushermainlenance. Milton 

### R. Young Station Unit 

### 2bas lwelve crushers [or cyclone coal grinding, cach dedicated 10 one o[the twelve cyclone furnaces. Diverting 

### as much as 30''/0 oflhe Lotal heal iuput 

### as rebum fuel could require four existing cyclones to be deactivalCd, and two new MPS-89 pulverizers to be dedioated 10 reburn fuel preparation. 

### As eaoh of these mills requires periodic maintenance, boiler emissions and/or load could 

### benegatively impucled during individualrebummill outage periods while lbeboilerremained in service. 

### A high level of ---.fiucness ofcoal particles from lbe reburnmills is important to achieve and maintainin order to limil

increases in f1yash combustibles. A minimum of6O peroent passing lhrough 200 mesh fineness is reoormnemlcd by one ofthereburn tcclmology vendors (B&W) for pulverized lignite rebum. Micronized 'coal reburnrequires even greater fmeness: 70_80 percenlpassing through a 325 mesh screen.

Pulverized or micronized coalrebum wilh the udvanced fonn ofsepari11ed overlire air (ASOFA) can be applied and installed on MRY Station Unil2's boiler_ These combined tcelmiques are expected 

### to reduce NO" emissions approximately 54% from current pre-control baseline levcls (down to 0.36IbhnmBtu) for the 

### MRY Stalion Unit 

### 2boiler. These levels ofNO"reduelion dependon lbe advanced form ofseparillcd overfire air leclmique to achieve the expecled NOx reductionpercenlages when applied 10 lignite-fired cyclone boilers, whichmaynol be suocessful given the conoerns expressed aboullhe potential impacts of lhis tcclmiquc. Using finely pulverized lignite forrebum fuel is considered leclmicaJ1y feasible forNOx emissions control under evaluation for application to

### MRY StalionUnilZ's boiler.

Square Bulle Electric Cooperative AI_II Burn'l &MoDonnellNOxBACTAnalysis Sluuy APPENDIX Al Technical feasibility ,\,.e"mentDelaUs for NOx ComrolTechnologies



### A.1.2.7.3 Fuel Lean Gas Reburn Another**~pproaoh** 

### to gas rebuming is "fuel-lean 

### gas reburn" 

### (FLGRTM) lechnology, which injects limited amounts ofnatural gas (approximately 3-10 percenl ofthe total fuel heat input) ahove the hurners 

### (OT cycloues) wilh or wimoul 'igmficanl air-stabrllg oflhc burners (cyclone") or lhe addition ofoverlire air upstream oflhe fuel injeetion elevalion. FLOR's first field-tesl on a cyclone-fired boilerwas at Commonwc"hh E,lison'" JolietUnil6 (327 MW), 

### a 9-eyclouc-furnocc boiler". NO

### x**emis~ions** reduction with FLOR (wilhoul SOFA) was believed to be approximately 35-40% with 7% ofthe boiler's tolal tuel heal input supplied in lhe rebum zone. This te.st yielded 0_59lblmmBtu No" emissions from" baseline of0.981<5. One olher cyclone boiler hos been modeled using compulational fluid dynamics (CFD) as part ofa study looking al applying 

### FLGR at Owensboro Municipal Utililies' "Elmer Smith Smtion Unil 

### I (150 MW single-wall, eaSlembituminous coal-fired boiler). This model prediclcd lhat No" emissions could be reduced by 25-30% over lhal achievable from overfrre air and SNCR"_

More commonly, FLGR"IM ha" been applied on medium to large pulverized coal wall-fired boilers burning eastern bituminous orwestern subbituminous coak On Wisconsin Electric Power Company's (WEPCO's) PI=nlProirieUnit 

### 1, a 620 MWg Riley**tUIbo-fiTc~** wet-bollom (olagging) boileT, FLGRfl'-1 alone was predicted to reduce NOx emissiotL'< by 35_39 percent at a gas rebum rate 0£7-8 percenlbm only achieved 20% from a baseline**ofO.~5** IbfrnmBtu"·". This**ispresum~bly** withoulburner**~ir-slllging** or SOFA. 

### It has "ho been "ppliell in combination wilh SNCR at tbis WEPCO site.

A potential advanlage ofFLGR"IM over conventional gas rebum is that lhe Fonner is generaily compatible with, but does not require, the installation and operation ofSOFA- The staged reburn DICl is introduced inlo an oxygen-rich atmosphere downstream ofthe burners and any OFA injeclion poinls. 'TI,e amount of reburn fuel injected is typieally limited by acceptable carbon monoxide levels in lbe hoiler exil flue gas.

There are potential impaots and limilation. unique 10 the firing ofNol1h Dakola lignite in cyclone-fired boilers that shouldbe recognized as pari ofthis emission reduction ledmology applieation_ This is signilicant, especially for alternatives withFLGR'J>J lechnology when combined wilh basic oradvanced SOFA to allow lherulcurnl gus**inlrOduee~** Hbuvc me SOFAparis (0 bum complerelyprior to 

### lhe fum"ce exit plane. ill eithercase, lhe amount ofadditional potential NOx reduolion pOSSlble with FLGR= is limited, since the rcburn fuel injection location is**cxpccte~** to coincide with the existing lignite pre-drying syslem vent porK The amount ofoxygen introduoed by the vent rorls will be <lisruptive to the fuel-lean '.

# ,

Bums &**MeD~nnen** Al14 Square Bulle Elewie CooperativeAPPENDlXAI TechnicalFeasibilityAssessmentDetail, for NO" Control Tcdmologics NO"BACT Analysis Study

reburn process in that itwould requiremuch higher rebum fuel injection fIltes in tbe lower secondary furnace to promote in-furnace No", reduction. There are reduced eoneerns thai the withholding ofa modest amOlmt ofheatinput from the eyclone barrels to use natural gas as a source ofrebum fuel may reduce cyclone temperatures enoughto inhibit slag formatiOn andflow, especially as boiler load is reduced. Air-staging the cyclones with theuse ofseparated overfire air to further complement combllition 

### NOx reduction is an optional part oflhis rebum technique which 

### will furtherrisk slag "freezing" iu thc barrels and lower furnace.

Fuel lean gas reblIDl can be applied and installed on 

### MRY Station Unit 2·s boilerwith orwithout SOFAIASOFA_ This te<:lmique is considered technically feasible for application to 

### MRY Station Unit 2·s boiler. Expected NOxTCdueliou will be modest for FLGRTM without SOFA and FLGRTM with a basic form ofSOFA. Unit operatiug and oapital costs to supply large quuntitics ofgaseous fuel not currently available at this site are economic disadvantages. Because ofthese factors, these variaticns ofthis technology wi]] not be COSl-effective compared to other alternatives with similar control effectiveness. FLGR'Thl without SOFA ami FLGRTM with a hasic form ofSOFA werenolineluded in the control e.ff<:ctiveuess and cost-effectiveness sections ofthe main report.
Oth.erdemonstraled [0= offuelle:m gas rebuming 1O combination withposl-combustiou technologies, such as amine--enhauced fuel lean gas.reburn (l'LGRTM with SNCR), are discussedunderthe layered technclogies section.


### A.1.2.7.4 Fuel Oil Reburn Fuel oil has been SIlbstituted for natural gas 

### in a conventional rebum applioaticn_ This is much less
common in the United States than using natural gas as a rebum fuel, due to the geneml lack ofdemand and djfficulties in supplying the volume offuel oil which wouldbe required. 

### Ilhas been installed commercially on three 350 MW oil-fired boilers in NewBrunswick(Canada) atthe Coleson Cove plant. NO", emissions reduction with rebum and SOFA was 78% with 25% oflhe boiler's tolal fuel heat input supplied 

### in the reburn ZOue. This yielded 0.22 lblrrunBtu NO", emissions from a baseline of 1.0 IbhumBtu". No examples 

### ofconventional fuel oil rebum applied \0 a coal-firedcydoneboiler were found in available lilcrnlure.

Fuel oil rebum could potentially be oonsidered for application to MRY Station Unit 

### 1 and Unit

### 2 boilers. Investigatiou ofthe specific source, dislance, and costs for supplying significantly increased quantities of fuel oil via transporttrucks hauling lanker tmilers orunderground pipeline to 

### M_R. Young st:3lion has not Squam Butte EJoclric Cooperative AI-Ij Burm & McDoJlIleHNOx BACTAnaly,i, Oilndy APPENDIX Al Teclmic.l Feasibility AssessmentDelails for NOxControl TechnologIes

been performed. The unit operating and capital costs to supply large quanlities ofhigh-volume liquid f05sil fuel at Ihis ,ite arc econumic disadvanlages. The COncerns regarding potential impacls and ]imilations unique to the firing ofNorthDakota lignile in cyclone-fired boilers !hal should b. reoogni:zed
as pa11 ofthis emission reduction lcchnology application are similar 10 Ihose expressed for convc'1ltional 

### gas rcbum. 

### II is believed thai potential NO" Gontrol wilh oil rehnrn would be shghtly les5 tban Gnmparable convenlional gas rGbum syslems.
Although fuel oil reburn could pOlentiully bc considcrcd fur applic",ion 10 MRY Slation Unit2's boiler, the laGk ofany distinctl'0tential NO" reduGtion advanlag.s and demollBtr"tion on Gyelone-fircd boilers doc, not appeur Lo support iLs consideration. TIlis alternative 

### wa.' not included in the NO" Gontrol and cost-effectiveness analysis.


### A.1.3 Post-Combustion Controls Posl-combustion controls deal with techniqnes thattherrnally or chemically-treat the flue gases to reduGe NO" emissions afterthey have Gxited the boiler's lower fllmacc: 

### In the cas" ofMillon 

### R. Young Stulion Unit 2, this primanly involves fonns ofseleGlive GatalytiG reduction (SCIl) and seleGtive non-calalytic reduclion (SCR) lcdmologics. 

### AnOlher emerging tedmology that has TeGenlly entered 11,e commercial

..,-; market is Powerspan's Electro Catalytic Oxidation"', which treats utility boiler flue gas forremoval of nitrogen oxides, sulfur OXides, and mercury. Another emerging teGhno]ogy thar has recently entered the wrnmercial uLility 

### airpolllltion control market is Powerspan's Electro CumlyllC Oxidation", whioh**lr~~ls** boiler flue gas for removal ofnitrogen oxides, sulfur oxides, and mercury.


### A.1.3.1 Selective Non-Catalytic Reduction (SNCR) Selective Non_Catalytic Reduction (SNCR), and variations such as hydrOGarbon-enhanGed SNCR (.old \Jnder Lhe mde name ofNOxSt",""), alld Rich ReagentlnjeGtion (RRJ), are all post-combustion types of boiler 

### NOx emission Gontrols. 

### While Lhe"c technologies UTG inscositivc to the spcGific fucllypcs whose combusLion produGls 

### are being treated, the large majority ofboiler appliGa1 ions to date have been on pulverized Goal·fired 

### lOuIS burning easlcrn bituminous fuels. SNCR

### has been uoed to reduce No", emissions on numerous ulilityboiler.\ burning eastern bituminol1' Goal, midwestern bihIminous coal, and, to a lesser extent, western subbituminoos coaL SNCR has also been us_d wi!h fud oil andnaluml gasfired units. SNCR (and hydrOGarbon-enhanGed SNCR) tedmologie, can each be applied to Gyclone boiler> with or without the use ofa SOFA system. SNCR does not appear to be dependent dircoLly on the type ofblJIIM" (w"ll-Iired, tangCllIially-lircd, and cyclone-fired) employed in Ihe boilers where ithas

Durns & McDoonell AI_L6 Square D\1tte Eloctrie Cool,crali,'oAPPENDlXAI TechnicalFeasibilityAssessmentDetails for NO" CoutIolTeohno1ogies NO" BACT Anal,!"" Study**,~,** 

### '.'

## , -

## .." been insmlled, with or wilhoutoverfue airiu full operation. Operation at ilicse planLs has demonstraled 

### lhat SNCR com decrease No", emissious as much as 15-40% at 

### full load, rnosl typicallybetween 25-35 percent!'.



### In the conventional SNCRprocess, 

### urea orarnmonia is injected inlo the boilerin aregion where the oombustion gus lemperature is in the 1700 to 2100 degrees F nrnge_ Under lhese lemperature comlilions, the urea reagent [CO(NH,j, ] or ammonia [NH, 

## 1rcacLs with the NO

### x, forming N, and waler, reducing NO

### x emissions_
I_ong-lerm examples where SNCR has been used lo reduce NOx emissions on two cyclone'firedboiler:;
are on a 

### 138 MW unil and 160 

### MW unit b1UUing eastern bituminous coal at Conectiv's B.L England Station (Units 1 and 2) since 1995 and 1996, respectively. Tests at these plants demonstrnted thal SNCR
can decrease 

### NOx emissions as much as 30·36% at full load, from**~round** 1.3-L41b/mmBtu respoolively to as low as 0.85 lblmmBtu (wiLhoutoverfire**air)l~",,,** _ These boilers, looated near ALlautic City, New



### . J=cy, conlinue to operale SNCR (with 

### OFA) for annual 

### NOx emissions around 

### 0.55 and 0.451b/rnmBUl,

.respeclivcly.

SNCR Can be applied and installed on MRY SUi-lion hoilers. Estimalcd NOx emission rales for using SNCR with NorthDakola lignite considered published levels aChieved by cyclone-fired units firing western subbituminous coal, and vendorpredictions. SNCR alone is expected to reduce**NO~** emissions approxirnatcly 37% Itom MCRbascline levels (downlo around O.5Ib/mnilltu) forthc.MRY Slalion Unit 2 boilerwithammonia slip limited 

### to approximately 5 ppmvd_ BeCiluse oflhe operating costs ofthe consumed reagenl, lhis technology will notbe cost_effective compared to oilier alternatives with similar control effectiveness (i.e. SOFA), SNCR alonc w.lS not included 

### in 

### the control effectiveness and cost· effectiveness seolions of

### the main report.

Olher demonstratcd forms ofSNCR-related technologies, such as RichRcagenlInjection with SNCR, and aminc-cnhanced fuel lean gas rcburn**(FLGR~M** 

### with SNCR), are discussed under Lhc layered lechnologies section,


### A.1.3.2 Hydrocarbon-enhancEld SNCR (NOxStarTM) Hydrocarbon-enhanced SNCRtechnology, commercially markelcd as NO"Star Thl
, is olTercd by a single vendor (Milsui Babcock) as a post-combustion type ofenhanced SNCR technology, whereby an

SqulIIe Bune Elecrric Co",cmive Al 17 B= & McDonnellNOx BALI Analysis Smdy APPENDlXAl Technioal fe

..ibili<y**Ass~ssmenl** Delails for NOx Control Technologies

ammonia-ba5ed reagent i" coniinuously injocled into 

### the "uperheaterlreheaterpass ofUn operating boiler WiIh small amounts of**g~SC(}US** hydrocaroon (typically either nalural gas 

### errpropane) and air Or steam to pmvidelancc cooling and aid reagenl dispersion. The targele<i GornllUstion gas temperalure range is between l500"F amI2000"f. -n,e amounl of

# g.,eous hydrocarbon introduced is small enough (0.1 to 0.2% oftotal fuel heat iopuI) lhallhis is not intended 10 UCI as UJom' ofreburn Or ,laged fuel combuslion. 

### An array ofpcrrnnncntly-installed injeclion lnnccs are located within thc boiler convection pnss, divided in Lo numCrous discrete ,.ones ueroSl; the full widtl) andheight oflhe duct. TIlC hydrocarbon auto-ignilcs, Jmming hydroxyl (OH) radicals which reacl wllh**lh~** NO" and ammoniu 10 produce elemental nitrogen (N,) and wat"rvapor (H 20).

NOxStarTM was dcmollStraled at Tennessee Valley Authority's Kingston Power Station Unil9 (tangenli"lly-iired 200 MW twln_flJrn",:e boileI firing eastcrn bitl1rninol1' coal) in 2002". 11ris lechnology wa> subsequCIltly pemmnenlly-installed atTVA's Colhen: SUllion Unit4 in late 2003 on a 192 MW wall-Dredboil.r burning eastern bilurninous coal"'. NO" rCduclion was "tated as 68-80% for these applicmions, which inclnded Ihe impact ofoverfire air nnd air-staged combustion upstream ofthe nmmonia and pl'Opnnc injection locations.



### An ."ample ofa hydrocarbon-enhanced SNCR installation on a wall-fired pulverized fuel boiler is shown 

## "s a sectional side elevation view oflbe upper [urna"e in Figure 

### A.1·3. .;

Burns & McDonncll AI-18 Square Bulle EleelIic CooperaliveAPPENDIX Al Technical Feasibility A,,,,,.,mentDelails for NOK ConlmlTechnologies NOK BACT Analy,is Sludy

NO"Starn, 3mmooiaihydrocarbonfsleam injeclion lance' (vertical lance' bciJind 'ecoodary superheaterinlet lubes



### Figure A.1-3 Hydrocarbon-enhanced SNCR Application on PC-fired Boiler2

-The snpplicr (Mitsui Babcock) ofhydrocarbon-enhanced SNCR technology claims !.here is lillIe sensilivily to lhe lype 

### fuel (coal) or burners this lechrliqnc can be polentially applied to in orderto rednce NOx emissions. The chemical reagent injeclion for hydrocarbon--enhanced SNCR (NOxStlIr nt) NOx conlrol technology must be preci,ely 10CIIle<l and carefully controlled 10 bc effectivc. Opcration oUlside ofthc required operating ranges can even result in incre"--Sed NOx emissions. Extensive C<lmputationnl fluid dynamic (CFD) model simulations arc**~eedcd** to detennine the optimum injection poinls and spray patterns_ lloiler operaling; comliliorl.'l change with unil load and varying fuel characlcristics_ The NOxSlarTM process conlrol system must be able to adjUSl for lhese changing conditions in order 10 be effeclive lhroughout lhe intended load rangc and [iring condilions encountered. Non-retractablc ammonia injeclion lances nmmged in a parallel-.eries marmer are pennanenlly mounled inside the upperfurnace zone, attached to**co~vcctive** lube clcments. Different scclion, of!he injection "grid" can be turned olfor on, depending On load and firing condilions and amount ofNOx reduction required. lnjedion nozzles are continuously purged and cooled by extraeled superhcated sleam from lhe boiler's main steam**outle~** whclhcrammonia reagenl is being inlroduccd into lbe -oue 

### gas**s~am** or**~ot.** Ammonia slip 

### can be minimized by injecting Ie" reagenl, al!hough NO" control perfonnance will be reduced.

Square Burte E1eClr;e CooperaLi\'e 1\1-19 Bums & MeDooUlcliAPP.ENDlX Al Tochnicol Fca"bllity A",e."mrnl Vel"j], [or NOx Control Toch.nologies



# ------- Ther" are a nwmbcr orissuos wilh /iring North Daku!" hgnite 

### that make the "pplioabiI it)' 

### (Ifby<h-ocarbon_ enhan""d SNCR infeasible compared to previous experience in olher "ouI-firod powerplant,. 'll,ese 

### i.sues inc1",lc:

•**HydrocarboIl-~Wmnccd** SNCR (NOxS"(arTM) tcchnology ha._ norheen applied to cyclone boilers (with or without the u,e ofa SOFA system). Hhas been only**"pph~<.I** (0 dale on p"lverized coal

### fired boilurs bUl1ling**caSl~TI1** 

### b,IUmlnOUS fuels. There is**~o** successful demonstraled llin_scale experience in continuOlli ,elVice ofhydrocarbon- "nhallced SNCR (NOxStar"") tedmology on units firing high-olugl,'lng couls suoh", western suhbiluminous (PRB) and llgnile. TI,e heat**I.rans[~r** surface" in lhe conl'eclive heat transfer 20ne where lh" reagenl mixlur" is**inj"~led** arc prune 10 severe foul ing fL'OLn 11yash consliluenls
common iLl Norlh DakOls lignite coals_ l'Iyash depo:;iL accumulalion on the oulside ofthe NOxSlar T

" l"ncc" in Millon 

### R. Young Sl:llion Unit 2 boiler's upper**fum~ce** is expeeLed (0 be**signific~n~** potentially occWTing within a**m~tter** ot-a few weeks from slmlup and nearly impo'>Sihle to prcl'cnl Orremove eHeclively during boiler operation_ Such buildup is expccled to Cause rnaldistribution ofthe NOx redllclion**chemic~l re~gent**  lium the injeelion nozzle'. Effective on-lme**reLllov~1** ofthese deposils from lhc injccllon nozzles is**amicip~ted** 10 he iIIsoffieienl 10 Tflllinluin**dr~~liv~** injc'Cliun dislribution and volume eOnlrot It IS anlieipaled that lhis would sigmficantly reduce the NOx emission ,eduction performance consistenlly aclliewd On
a slIslainahle basis_

Th. lack ofezperience wi'h cydoLle boilers. especially those firing co"l with severe deposition characteristics suelt as Norlh Dakota lignI te, make.' lhis lechnolog;y technically infe"sible for application
on the Milton R_ Young; SlSlion UniL 2 boiler.


### A.1.3.3 Rich Reagent Injection (RRI) Rich Reagent**fnj.e~on** (RRl) is a 

### NOx control process that bas 1>-""'n developed and dmlOnstraled specifically 10rusc On cyelonc boilers. Rich Rcagonl**fnj~elion** is an SNCR proce"**th~t** involves**lh~** injeot'on ofaqUCOU5 Ufc" inlo the lowcr fumuce b.lwoen lile cyclones and the SOfA porK 

### Rill l"rgels" hig;h**l~,"pcmlure,** fuel-'"ich wne

## w, thin the hailer-furnace**envirunm~lll** irrunediatcly "djacenl 10 tbe oyclonehllmer", m,d require, temperutllTcs in lhe 'Jnge of2400 to 3100 dcgrec, F.

The three ZOnC:; ofa Wch Reagenl lnjcdion SNCR applicalJOn Oil a boiler ,vilh**"q",ml~<1** ovcTfire uir Un; sbown**~s** a seclionul ,ide dcv"liun view ofthe [um"ce ill Figure A_l-4_ 

# ===-----""',------c==c=c== l'lmllS & McDouuell AI 20 Square nutte Elemic CoopLTIllivc

### APPENDIXAl TechnicalF=ibilityA."",srnCTIIDelails for NOll Connol Tecbnologie,



# OFA

phemicalt/!l Injection

Fuel NO" BACfAnalysis Study



## Burnout

## Zone

Fuel Rich 

## Zone

Staged 

## Combustion 

## Zone

Figure A.1-4 Rich Reagent Injection Application on Boiler With Overfire Air3

The Rich Reagent frljection (RRI) processhas been successfully demonstrated 

### on aLleast two cyclonefired boilers, wilh lhe mosl recent installation 

### at Ameren's Sioux Unit 

### I, a 500 MWboilerfiring a blend ofPRll andmidwesternbilurninous coals_ Generally, lheheat content ofthese coals typically varies very little. Short·lerm testing oflhe 

### RRIprocess has beenperfarmed alone and in combinationwith SNCR on 

### BL England 

### Unit I in 

### 1999"''''', and more recently atAmcren's Sioux 

### Unit I in 2002""', in 2004" (alone), and in 

### the firsthalfof200S" (alone, and wilh 

### SNCR).

The 

### RRI proress 

### is intended 

### 10 be used oulywith air-starved (subsLoichiometrie staged_air) cyclone combustion, 

### in eoujunclion with the installation and operation ofun OFA system_ The RRIprocess has uot 

### been demonstrated on anyunill1lal fires North Dukota lignite. As ofOclober 2006, no commercial installation of pem1anenl Rich Reagent Injeclion system has been made at any cyclone-firedboiler_

Square Bulle Elecnic Cooperelive AI 21 llurns & McDonnellNO" BAG[ An.lysis Study Al'I'ENDIXAI TechnicalFeasibility AssessmentDeloils for NO" ControlTechnologie,

There is only one holder ofa oommereiallicense for modeling; and conccptu"lIy designing RRI (Reaction Engineering International), witil two vendors sub-Iiccw;ed to design and sell RRl equipment (Fuel Tech and Combustion Components Associates). Since these license agreements 

### are inplace, and considering that successful dcmonstmtion Icsting; h"" beenperformed al two cyclone-tiredboiler powerplants,**lIri~** Icchnology is cOllsidered to be applicable and commercially**~vail~blc** for potenli"l application on cyclone boilers whioh bum coals wilh heal conlents Lhut merelatively constant However, due to the variable heat content oflignile coal, RRI is considered to 

### he te.;lmieally-infeasible [or applicalion on

### North Dakota lignite-lire<! boilers. Technie.l f=ibility and e"pccted 

### NO" eIllissiolls from 

### RRT for applioation on!hc Millon 

### R. Young Station Unit 

### 2 boiler are included in the ··LayeredNO" Redllction Technologies" 'ecrion.


### A.1.3.4 Selective Catalytic Reduction (SCR)
n,e lowesL

### NO:>: emi&sion levels from coal-fIred utility boilers are typically achieved by inst:lHing uud opcrating selective catalytic reduction (SCR) technology. 

### In tile SCR**proecs~,** the gas sITeom 

### is pa"-<ed through a catalyst bed in !he presence oIummoni. to reduce 

### NO

### x to molecular nilrogen and water. The process is lcrmcd "selective" because the ammonia preferentially reacts with !he 

### NOx**ruth~"I** than withthe oxygen in the flue ga,. 

### A catalyst 

### is used to enhance 

### NOx reduction and ammonia utilization at**~ppropriute** flue gas temperatures. SCR is usually applied 

### to flue gas in Ihe 600°F to 750'F temperature runge. There are vari.tiolL' in the SCR process 101' coal-fired boilers thal mostly involve locations in the flue gas path where the caLu]yst is placed in order 10 promote the desired NOx emission reduotion effeeL These 

### are desc"ribed below. 

## ,..

A.1.3.4.1 High·Dust Selective Catalytic Reduction (HD-SCR) For coal-fired boilers. a conventional SCR reactor utilizes readily-available catalystmaterials and reagenL in the form ofanuuonia. A convenlional SCR reactor is commonly installed in a high-dust, hot-side arrangement, locaLed between !he ceonomiZL'r outlet and "ir heater inle1, wbere the flue 

### gas lempernture is within the desired opefJting rnnge for Ihe SCR calalysL The conwntioml SCR reactorarrangement is preferred for mosl coal-fired applications in olility boilers beea'-'-'" it avoids the added expense of reheating the flue g"s ifplaced arter the air heaters which cool thc flue gas, and downstream ofany 

### flue gas treatment Lo n.'TI10vc ucid gases. Conventional SCR tednology uses an**anunoni~** injecLion grid (AIG), which consists ofmultiple nozzles, for distributing !lIe reagentinto the flue g"s at the boiler's economizer flue gJS outlet.

Burn, & McDonndl AI-22 SqlJllre Bulle Electric C""l'cmli,,"APPENDlXAI Technical Feasibility A,,,,ssmelll Dc,"jl, for NOx Qmllol Technologies

---------------- NOx BACT Analysis Smdy

A schematic graphic diagram for a conventional high-dust, hot-side SCR system on a boilerwith a nue 

### gas dcsulfurization system and stack gas reheat is provided in Figure A 1-5_ 

### Figure A.l-S Conventional Higb-Dust SCRArnmgement with FGD Scrubber OulletReheat 

# High DustArrangement 

# CD Steam generator 

# ® Regenerating heal rxchanger 

# ® A;, 

# @ Electrostatic precipitator 

# ® 501

-Scrubber 

# ®



# ® SCR

- Reactor 

# o Catalyst 

# ® Vaporizer 

# ® Ammonia/ Air· Mixer 

# @ Ammonia storage tank
(ftgJJre copied from WheelabralorAi,- Pollution Conlrolliteratllre)

Conventional high-dnst, hot-side SCR technology has becn instnlled On several pulverized coal and cyclone boilcrs firing bitnminolls and ,ubbilllminolls coal in the United States. Thero are also a limited nllmberofEuropcan SCR installations on steam electric generating units (SEGUs) firing lower grade (brown) coal. There are, however, no existing full-scale SCR installations on units that fire North Dakota

Square BIlllC Electric Cooperative Al-23 Burn, &**McD~IUlell**NOx bl\CT ;'.r"ly;l,**~wd)'** APl'JiNDlX AI Tcchmc"l Foa>ibiTi<y M.sc"men, De",I., for NOx Control Technologies

------._- lib'Illlc. TkTC**ar~** approximately 

### 50 cyclone-fired units localed in tne**5tal~s** aff<X:icd hy EPA', NOx 

### SrP call. Over hal

### rofIhe"" unils are planning 10 inslall conveniiOrull hig-h-dusI, hoi-,ide SCR systems in response 10 the SiJ' call. "I11e inslall"lion of**oonv~nLional** high-dust, hoi-side SCR**sy~lems** has been**compJcI~d** On approxmmtd)' 

### 22 oflhese uniK Appendix 

### A2 Jists ,eveml convClllional hig-h-dus; hot-side IJ.S. SCR ins",nations On**p~lverized** coal and cyclone-fired uliliry boilers, along WIth mea'W"ed No" clnlssion,. Inili"l dalu from Ihe,c uniIS indicnte that convcnlion"l high-du'I, hol-sidc SCR,ystems operated on suilable cycJonc.[ired unil' may 

### be able to reduce NOx emi,sions 10 as low

.., 0.07 Ib,;/mmBlu. Several SCR iostallalions h"ve beCll rclrofiL On exisling cyclone-fired boilers burning we,tern subbitmninous coal (or PRB blended with midwestern bitummous coal). For cyclone coal_lired uillily b"ikru rctrufiUed with 

### SCR leehnology, all were origin.lly designcd 

### 10 blJITl bituminow, e""l.

The EPA NOx SIP cull only applies 10 unils m Ihe ea,tern Uniled Slales. There are nO faoiliIies Iiring North Dakola lignite m the EPA NOx SIP call regIon. SCR sy,lem operalion is currenlly unly needed dUring the ozone seawn (June

- Seplemher) for llIlit.> in'lalling conlrol equipmem solely to meet 

### the EPA NO

### x 

### SIP call requirements.**Limil~d** <lIlllual opernlion 

### is a Slgnilic"nt facLor wiLh n"l'ccllo 

### SCR equipmel11 reliahility, mainlenance, operalional costs, and catalyst 11 fe. TI,e demands 011 the SCR syslcm
are much more**SCV~"["** iflhe**~"(luipmont** IS required 

### to operato 

### on a full-timo, annuul basis.

Two byproducl, from iho high_du't, hot-side SCR process are ammnnia slip and SO,:

• A"'m"ma Slip; Shp i, ununonia that is ULlreacted in the NOx emi,,;on**rodu~liOll** prooess. Maximum ammonia slip for a gas fired unit is usually 10 ppmvd whereas, on a coal fired unit, anmlOnia slip helow j rpm is desired. For certain applications, Ihis concentration can 

### be problemalic, thorefore rcquiril\g more catalyst to reduce slip_ Mosl neW SCR application., have arrunonia slip guaranteed at a 2 ppmvd n:lllx;mum f"r an initial operalingperiod.

• SOl: Due 10 the composiIion oftypical SCll cataly,ls, a small peroentage ofinherent SO, will be oxidi7.ed 10 SO,. Th,. oxidation can he oontrolled by oatalyst selection and oaLl be les.s Ihan OnC percent. S02 to SO; oxidation must be carefully controlled to avoid creating SO] levels sufficiently high to rai'" the posSibiliry ofairheater fouling. A mlit tiring high_1;ulfu,' coal with SCR lechn"logy is especially vulnerable 10 SOJ m.idalion and ammonia slip-relaled**f"ulin~** problems_ The dcposilion and fouling i, duc 10 formation ofsolid ammonium wlIuIC (NH'hSO,) and Eqllid ammonium blsulfate (NH,I [SO,). 11,e most important design variable is oplimizing the catalyst**s~leotion** and am"unt 

### of calalysL Ihat will reduce 

### NO"**~"llli""i"ru;,** "ontrol alnmonia slip, and mmimi7.e SO, oxidulion.

nams & McDonnell Al 24 Square Butte Electric Cooperatj;/eAPPENDlXAl TechnicalFe"ibiUty Assessrru:nl**De~i1s** for NOxControlTechnologic, NO" BACTAnalysis Study

Recent technologyhas allowed catalyst suppliers 10 make more rigorous andlengthy guarantees. A Teasonnblc initial operating period for conventional catalysIs in high-rlusl reaclornmmgements on boilers firing eastern or midwestern bituminous coal is aronnd 24,000 active operating hours (i.e. when anunonia reagenl is being injecled). Factors lhat need 

### to be taken into account in design ofa high-rlust, hot-side SCR application lhat affect the need for calalystreplacement are:

6 Pr=ure drop: The amount ofrestriction 10 .flue gas flow through the scn inlet, anunonia injeclion grid, SCRrcaclOI. and downslream ductwork directly increases induced draftfrnhorsepower required 10mainlain adequate boilerdraft. This is animportantparameler 10 consider and minimize during the desigu slage_ Pressure drop is a function oflhe average and maximum SCRreaclorduct velocities, the amount ofrestriclion caused by flow distribution correction devices (baffles or vanes), andihe number and geometrical asfl"cts orlhe catalystlayers_ Manyretrofil SCR installalioru; require a boosler fan or opgradcdinduced droit fan to overcome the added flow resistmce. This increases operating cost for 

### !he increase 

### in auxiliarypower- eonswnplion and loss ofsaleable electric power_The type andpilch ofthe calalyst are factors most influential 

### in determining 

### !he amount ofpressure drop.

)- Catalysttype: 

### The most common types or fonus ofcatalystm,terial are honeycomb orplate. The former offen; more surface area per-volume, but can be more restrictive and prone to pluggage from ash deposils. The laner is usuany If'SS restrictive butrequires more catalyst 

### per layerOrmOre layers 10 achieve the active surface needed to achieve the intendedNO" emissionreduction.

'" Catalysl pilch: The pilch oIlhe catalyst, a term used 10 describe the size ofUte gas path openings through the catalyst, varies depending on the manufacturerand design dust loading_ Pitch is gene."lly on lhe order- of5 to 7 millimelers. Potenlial pluggage offlow channels within the calalysts layers is therefore an issue thatmustbe dea\( willi during design.

• Calalyst performanoe: The amount ofNO" emission reduction expected is a ftmclion ofthe specific activity level ofthe catalysl material and 

### the amount ofcalalyst installed, overa given period oftime. Catalysl formulation selel:lion and features ofconstruolion have a significant Impacton long-I.errn NO" emission reduction and snbsequent costs forreagent and catalysts replacement. The frequency ofcutalyslreplacemenl is influenced strongly hy: 

### l> Catalyst erosion: Erosion oflbe catalystmaterial 

### in coal fired units from Clltraincd f1yash or sootblowing action reduccs the amount ofactive surface available for reacting with lhe reagent and flue gas, and can oause distortions in gas distribution ("channeling'') through lhe

SquaTC BUlle Electric Coope""ive Al-25 Burns & McDonnenNOx BACI An.lysis Study APPENDlXAI Tcdmieal Fea,ibilily AssessmeTltDetails for NOx Control Technologic,

SCRreaclOL C"'lnlyst material is fragile and ellIl be casily damaged_ Some catalystis provided with erosion-resi"lant lop edges 1o mitigate this tcmkncy. }- Moisture absorplion: Many types ofoalalysl are damagedby absorption ofmoi"ture. The rcaclormus( be kept ahove ambient dewpoint lemperatures orproleded from freczing during outages in order to prO[eclthc ealalysl from moisture damage_ Spare oatalyst must be carefully packaged 10 keep it dry and must

### be hnndlcd delicately 10 prevenl damage_ }-**Th<;r:m~l** degradation: The speoific**a~livc** elements ofthe catalyst surfaoe, or the matrix stnlcture itselfupon whioh the catalysl malerial is applied, cun degr"dc when exposed 

### to flue gas lcmpcrolures grealer than lhe intended design oflhe formulalion. High flue gas lemperatures within lhu**r~"\lulOr** CnuSCS sintering, leading 10 a permanent loss ofcalalyst activity due 10 a change inthe pore structure ofthe cataly"l.**ProP~T** sclcclion aLld manufacturing conlrol ofthe catalyst struoture and formulalion can minimizc lhermal degradation. 

## >- Cat3lys[ poisoning, The loss ofperformance or activity ofthe catalyst over limc Can be due 10 ohemioal damage or poisoning. Two elcments espeoially detrimental to lhe life ofcommon litanium-supported vanadium penloxide SCR catalyst are arsenic and zinc_ Vanadialtungslen-buscd caLalysts are pariiou]arJy susoeptible 10 rapid deactivation due 10 gaseous arsenio poiwning. Jn some German SC"R imlallalions, a 50% loss ofactivity has beenreported within 10,000-15,000 operating houIS. Addition**ofmolybd~l1l1m** III Uvanadiulilamum SCR c"I"lyst On similar applications shows relative activity reductions of20-25%. Progressive Joss ofSCR NO" reduction performance from caluly"ldcactivation due [0 poisoning is not possible 10 restore without effeclive deaning lo R"TIIOVC the deposits, or cvenluul replacement. 

# » Calalyst fouling: The ,,,rfaoe area pOK"lllially exposed 10 Ihe reagent (ammonia) and nitrogen oxides in the flue gas oan become fouled with flyush or sulfur-relaled oompounds_ The presenoc ofexcess <:a1cium oxide in lhe presenoe ofsulfur in the flue gas con form a culcium .ulfale surfuoe coating that can be extremely den,c, Irulsking lhepores tlrlhe catalyst. Progressive loss ofSCR NOx reduction performanoe from catalyst deaclivalion duc to fouling is difficull ltlrest<m: wilhoUl cffeelive cleaning to remove the deposils, oreventual replacement.

SCR leclmology hu" bccn inslalled on numerous ooal-fired utility boiler fad1i ties around the world und there arc a huge number ofmanufacturers lhat market the oalalyst". The question is whether SCR is a

Hum, & McDonnoll AI-26**S~u.re** Butte Electrio C,.<lOp"",tiveAPPENDlXAI TechnicalFeasibilityA"es,menI DemUs for NOx ControlTechnologies NOxBACTAnalysis Study

feasible tedmology for a unit firing North Dakota lignile_ There are serious concerns whetl1er instanation ofSCR technology on a North DakolD.lignite-fired unit can be successful, especially ina convcntional ·'hot-side, high..<Jusl" configuratiolL The effectiveness ofthe SCRprocess is highly**depe~dent** upen the**~bility** ofthe nitrogen oxides 

### in the flue gas being able 10 contllctthe active sites withinmicroscopic pores of!hc catalysl in the presence ofammoniareagent with minimal interference from conlaminants.

A recenttechnical paper "Ash and Mercury Behaviorin SCR Catalysts When Firing Subbituminous and Lignite Coaisn by the Energy & Environmental Research Center (EERC) ofthe University ofNorth Dakota 

### was published in the February 2005 issue ofFuel ProcessingTechnologymagazine". Thispaper summarized theresults ofSCR slipslre3lIllCsting attwo PRB-fm:dplants and one Norlh Dakota lignitefired powerplanl. The cvaluation included dclcrminaliou ofirnpacts ofash on SCRplugging and blimling. Flue gas was isokinetically extracted from the convective pass ofLhe boiler upslream o( Lbe air heater. Pressurc drop aero"" the catalyst 

### was measured during the initial two-mouth lest period. and the two consecutive lwo-month testperiods following 

### the initial trial, while holdiug flue gas flow and temperatures constant. Ammonia was injecled clownstream ofa**scre~"U,** upstream ofa flow straightener and an-pulse section. Compress<.-d an- was injected ahead oflhe reactor, and was periodicallypulOO<llo



# -simulate sootblowing to minimize ash deposit accumulation_

, .' This slipstream SCR testing cxamined the significance ofash accumulations on SCRcamlysl on boili the

"mao;roscopic andmio;roscopic levels_ Very small flyush particles were fOWldbonded togetherby a malTix

ofsodium-, ca]crum_, andsulfur·richmalerials, likely in lhe form ofcalcium sulfal.e. NorthDakota lignite coal contains many alkali and alkaline-earth elements, and sulfur. The firing oflignite coal which produces fine ( less than 5-l.lm diameter) llyash particles creates conditions that enter thc pores ofthe catalyst, react with SO, 

### -in the Oue gas, and form sulfates which bind other ash particles into Lbe malrix_

As posted on Elecbic PowerReseilrch Institute me. 's (EPRI's) website regarding 

### the impactofcoal type On SCRcalalyst life 

### andperformance, a recent 

### EPRJ study'" produced (ield data analyzedfrom an '·InSitu Mini SCRReactor" systeminstaJ1ed in a typical "hign-dust" location at seven diITerenllcsl sitcs, including four firing PRB coal, one firing Texas lignile, oue fuing high-sulfureastern bituminous coal, and one (iring a PRBteasternbituminous coal blend. The PRBfbituminous coal blend testwas perfurmed at ArnerenUE's Sioux Station, on one of1.he 

### two 500 MW cyclone-fired bOllers. This study fouud lhal lhe cyclone unit firing 

### the PRBfbiluminoU5 coal blendexhibited thc fastestrale ofcatalyst activity degradatiou. 

### Also, the higher deactiwtion

### I1ltes """" at lhis sitewere due to economizer cxit_flue gas
Square BntIe Electric Coopo:rative AI-27 Bum' & McDonnellNUxBACT A

. .Ilalysis Study



## ------ APPENDIX AI Technical FeasibilityAssessmenl Dclail5 for NOx ControlTechnologie,
lemporatures being signilicanlly higher lhan at thc other sites. A comparison oIlhcTcxas lignite and One ofthe PRE-fircd sites wilh two different catalysIs, deactivation W;ls more a function oftrnce e1emenls in thc flue gas aud flyash than thc sp::cilie catalyst type Orformulation.

North Dakota lignite produces an ash lhat is very slicky "nd creales severe ush deposition problems. There havc been no installations ofSeR systems (full-,cale) 011 ullits lhal fire North DakOI;'Clignile. A tcohnical assessment was collllueted for the instaljation ofSCIl technology On a NorthDakota lignilo unil. In order to further evaluate the feasibility ofinst"lling a convelltional SCR system on a North Dakola lIgnitc fired unit, the Energy & Enviromnental Research Center (EERC) at the Univcrsity ofNorth Dakota was consuHed. EERC has e:xtensive expCriCIICO investigating rhc dcposition characteriSlics of North Dakola lignite ash.

l'eclmical dilficullics and anticipated operating problems that are unresolved with respect 10 inslulling convcnLional 

## sell lechnology at Milloll 

### R. Young Stalion include the impacts oferosion, severe ash deposilion, and "popcorn ash" on lhe catalysl. According the EERC's study (see Appendix Il), "thc mosl sigIlificant problems that prohibit lhe succc,sful operation ofSCR c"lalysts to lignite coal is tho fonnation oflow-temperatul'e sodium-calcium-magnesium sulfates and phosphates that will form on lhe surfaccs of calalysts and lhc carryover ofdeposils thar will plug the calalyst opening" resulting in inc,eased pressure drop and**dC~Teased** efficiency". Forthesereasons, applicalion of"vailable**conven~onal** high-dust SCR technology is considered lcchnicully infeasible for Milton R. Voong Slation Unit I and Unit 2 boilers. 'These concerns Can be divided inlo foul' calcgories. Each categ<Jry is addressed below. An explanation of lhe factors lhalmako conventional SCR technology infeasible for thesc boilers follows:

1. Ash Deposition: North Dakota lignite contains a variable and complex variety ofinorganio compounds that cOlltribule 10 ash dcpo,ilion. This fuel produces ash with severe**d"Po~ition** cffilmcleristies that are nOllypioal with other coals. When e:<posed

### to thc hCal ofthe combustion process insidc lhe cyclone burne,s, lhe rruljOrity ofthe fuel ash becomes molten and flows inlo the bOllom oflhe fwnaee. A significuntportion ofthe fuel ash is entrained into the lluc gas exiting the cyclonebarrels athigh velocity, where il COmes inlo contuclwith lhe lowerfurnace watelWalls. Theportion that is carned with thc rising flue ga. cools and some is deposlted on beal lr.:msfcr surfaces in the upper furnacc and boiler convectionpass. Ash depositioll 011 heat transfer surfaces is a substantial problem for units thaI fire North Dulwta lignite. 'The problem i,
so scven: at Milton R... Young thn! the Unit 2 boiler mustbe shul down al 80 Lo 90-<lay inlervals 10

Durn, & McDonnell AI-28 Square B**l~tc** Electric**C(}{Jptra~vo**APPENDIXAl Technical**FeaSlbi~ly** Aascssrnenl Detail. for NOx ControlTechnologic. NOloBACT Analysi. Srudy**.'~** allow for cleaning ofO5"h deposits 

### from the boiler heal transfer surfaces in order 10 reslore reasonable furnace exit gas velocities and lernpero.tures_

Sodium is a significant contributor to the "stickiness" ofthe ash produced from firing North Dakota lignite. Sodium cOnlent oft"he lignite ash averages approximately4.4%, and can nearly 

# ',--'

. double l"his value for 

### Some ofthe lignile produced from the Center mine. 

### PRE coal typically 

# "' averages around 

### 1.5% sodium content. Boilers firing Nort"h Dakota lignile typically have a 

### 2_5% hig"herheatrnte (million Btu. per ]ciIOWlltl ofelectric generation) than a typical boiler firing PRB coal, thus requiring mOre heat input and firing more fuel per megawatt ofeleGtricity output A cycloneboiler Gring North Dakola lignite also converts approximately 50% ofthe fuel ash to fiyash, compared with a 

### 35% conversion rnte for PRB cllal_fired cyolone boilers. Ovelllll,lhis results in an amount ofsodimn emitted from a cyclone boiler firing North Dakota lignite of approximately 

### 7.3 lbs/MW-hr compared withO.9IbsIMW-hrfor a PRB_fired oyelllne blliler.

The calalysts in cnal-fired boiler SCR reactors are highly susceptible 10 ash deposition. 

### In a typi""l oonventional higb-dust SCRreactor, the flue gas typically passes through two 10 filar layers ofcatalystmodulcs. The catalyst modules have numerous nalTlIW passages to provide intimnte contact between the flue gas, arrunonia and cataly.;t The c1e=nce (pitch) in these pa.o>sages is typioally 

### 6_10 millimelers_ 

### A typical catalyst layeris approximately 

### I to 

### 1.5 meters deep. The catalysts in coal-fired boiler SCRreactors must be cleaned frequently using sool blowers and/or sonic horns. This is true even on units firing fuels thatdo nllt prnduce**a~lioky** ash Ihal contribules to ash deposition. Ash deposition on Ihe catalyst in a high-dust SCRapplicalion would be severe for a unil firing NorthDakota lignite_

Sulfur in the coal is oxidized during excess aircombustionto form sulfur dioxide (SO,), and a 

### amaH amount ohuifur trioxide (SO,). Some IIfIhe ammonia-based reagent injected upstreamof the SCRreaclor will combine with SO;, to form ammonium bisulfate. The o:ataly.;! 

### in 

### the SCR reactor will also oxidize a portion ofthe So, to SO,. Excess unreaoled ammonia reagent carryover ("anunonia slip") 

### from the SCR reactorwHl also react with these sulfuric acid compounds 

### in a similar fushion. The deposition charaoleristics for a IlllitbumingNorthDakota lignile will creale difficult-Io-remove ash depoails and pluggage ofa conventional high-dust catalys!, llJId inorease the prohability that the airpreheater downstream and flue gas ductwork will be prone to accumulations whioh couldbe :;everc. High-dust SCR performance and oatalysl life

SqoareBune EJeclric COOpCIlllivc AI_29 Bums & McDoarn:lINOx BACT Aualysis 

### SlI1dy APPENDIX AI 

### Technical F"",ibility Assessment

### Details rorNOx 

### ControlTechnologies**---------------~----** 

### will be severely impacted. It 

### is anticipated Ihat a high-dust SCR's cataly,;t life win be shortened from 

### ),6 years (typical) to as liti;le 11S 

### 2-12 months, requiring cXlended, frequent outages for II.'pIUGL"1I1cnL

HoI-side 11irprehealers are susceptible to fou]jng_ Tubular air pre healers originally supplied with all cycloneboj]ers 11lso lolcra

### to modcralc dust loadings, since (hcirheighl and size make them difficult to JlliIiulaiu cleanliness. Leak lightness ofthe air preheater is important on cyclonc-fIred boilers willi relalively high forced dl1lfi [an 

### discharge (combustion air supply) prc,surcs. A 

### highdust SCR insl11IMion will 

### bepronc to airprehe,ler tube fonling and pluggage, requiring e"-Iended, frequenl outages 

### for cleaning_



### 2. "Popcorn 

### Ash": A sceomJ considemtion in lhe application ofconventional high-dnst SCR ledmology on a lignile-fired unit is the potenlial ofthe SCR reactorcatalyst plnggage Tesulling fmm carry over of"popcorn ash" from Lhe boiler.**Boil~'rS** 

### fIring North Dakot, lignite have severe problems wilh ash deposition on boiler surfaces. North Dakola lignite has a high propensity to form deposits on lhe bOller's furnace and convection pass fireside surfuces. For lignitc-fIred nnil', the boiler's heat tronsfcrsurfuces must bc cleaned by soolblowing and othermethods (e.g.**wal~T** 

### bmces) freqnenlly to maintain satisfactory boiler operation_ Some oflhe removed deposils released by lhe cleaning action withinlheboiler and convection p=es form ''popcorn u8h", which will be entrained in Lhe lluc gas. Curry "vcr ofboiler ash deposits 

### will contribule 

### 10 pluggage ofthe ·'popcorn ash" screen ahead ofthe lop layer ofSCR reactor catalyst. This can cauSe distortions in gas distribution ('"channeling") through the SCR reactor, which 

### will uggravate erosion 

### in the high velooity areas and ineffeclive performancc oflhe catalyst



### 3. TemperatuTc: 

### A third issuc that imp,els lhe feusibility ofinslalling bigh.dnst SCR techuology on lhe 

### North Dakota lignite-fired nnils is calalyst operating temperature. Thepcr[ormunce ofany SCR calalyst is highly**d~'pcn<l~'llt** 

### on the lempcrnlure ofthe flue gas passing through the reactor. Typically, a lemperature of

### 600

- 750 degrees 

### F is required to obtain salisfactoTy**oper~lion** 

### ofan 

### SCR reactor. Opcl1ltion ofcommonly suppliC<l calalyst suilable for a high-<1nst SCRreaotor at lempcrnture.s above 750 

### degre"S resulLs in severe and rapid llclc:riomtion oflhe call1lyst and SCR reactor's NO

### x cmission reduction**p~'[fmmanec.** 

### For bituminous and sub-bituminous coal_fired llIlits, boiler flne gas p"-<singbetween [he economizero"Llct and airhealerinlel is gencrally

Bums & McDonnell AI-30 

### SqnaTc Ilulto E1cctTic 

### CooptlaliycAPPENDIXAl TeclmiC<l1 Feasibilily Assessment Detail, for NOx Control Technologics NOxBACfAnalysis SlIldy

within a temperature rnnge acceptable for convenllonal SCR calalysls without additional healing
or eoolingoflhe now stream.

North DakOla lignite-fired cycloneboilers, including those at Milton R, Young Stalion, have high lemperatures at the economizer's nue gas oulletby desIgn. The highest gas temperatures down>tream ofIhe convection 

### pans economizer sections and upstream ofthe air heater inlcts in .MiltonR. YoungUnit 2's boiler 

### are mucQ. higher than 7511 degrees.
High gas temperatures al Ihe air heater inlet are required 10produce the high air temperatures (711110j7) needed forthe pre-combustion lignite drying system, along

### with primary and second;rry combustion airsupplied to the cyclones. Such air prehealer arnmgemenls and capabilities have been takeninto accmml 

### in thc design ollhe North Dakota IIgnile-fired cycloneboilers. Reducing Ihis high gas temperature 10 accommodale conventional catalysts 

### for a conventional high.<Jusl SCR reaclor would result inpre--<:ombustion air lemperatures Ihat are too low to provide satisfactory dryIng and rapid ignition ofIhe high_moisture fuel. This will seriously impact reliable combustion, slag formation and lappingin Ihc eyelone burners. Consequently, it is not**fe~ib]e** to modify the Milton R. Young Unil2's boiler 10 operale wilh the lower economizer outlet Due gas temperature.
Ollalysts for n conventional high-dusI, hoi-side SCR systemhave nolbeen Installed nor successfully demonstrated in a full"cale installation oIan OPerilting solid fucl-frred unit lhalare designed 10 continuously operate al the high 1>:mperatures (above 750 degrees F) thaI exist between the convection pass economizer and airheater on the Milton 

### R. Young Unil2's boiler.



### 4. Ero,ion; A£inal consideration on**wheth~T** hol"lde, high-dust SCR teclmology can be successfnl
on a North Dakola Iignile-fired unitis**Ihepolen~a1** for erosion ofthe SCR calalysL North Dakola lignite supplied from the Center mine has an avernge fuel ash conlent ofI0.5%, and can have an ashcontent up 10 25.5 percenL PRB coal fuel aohcontcnt typically averages approximately 5 perrent. As previously stated, a cyclone boiler firing North Dakota lignite converts a significanlly grealer amount offlyash than a PRB-frred cyclone boiler. Overall, 

### this results in a nyssh output rate 

### rrom a cyclone boiler firing North Dakola lignile ofappro

### ximalely 831bs/MW

### In- C<lmpared with21lbsIMW-hrfor 

### aPRB-fired cycloneboiler. High ash con!cnts in the Due gas 

### stream can resull in physical erosion ofthe catalyst. 10 addition, effective on-line cleaning orthe

Squ"o Butte Electric CoopCTlllive A1-31 BulIlS & McDOIlIlCll

### NOx BACT Analysis Stwly APPENDlXAJ Technical Feasibility AssessmentDel<lils forNOx ControlTechnologies
high-dust catalyslwill likely require Sleam or compressed airsoolblowing. Clconing oyoles of the catalyst will be required much more frequenlly LImn a typical conventional SCR installalion duc to the ash deposilion characLcristics ofthe North Dakola ligniLc amI lhc cxpecled buildup and pluggoge resulting from the oarry overof"popcom ash"

_ Frequent soolblowing ofLhc oalalystto
remove fouling dcpo,ito "ml ush ,cculllulatioll'> will conlribule lo ero,iou ornJ decreased cataly"t life. 

### There is sonle Europe,n experience wirh high ash brown coals that cotalysl manufaoluren; will be ohle to 

### draw upon. This**c"perien~e,** 

### however, will 

### nol bc directly oppJicable to these Unilw SMcs units becouse ofthe severe deposilion char,cteristios ofthe North DakOlfl lignile**~sh** 

### compared lo 

### brown**co~L**


### The EPA's NSR M,nual slates that for a lechnology 10 

### be fcasible it must '"ava,lahle and applicable"_ 

### SCR tedmology is an available leclmology whioh has been m,;jal1ed on nUmorouS powerplant facilitics arolll1dthe world and**lh~Te** 

### ,re a large number ofmanufacturers th,lJIllirkel the technology_ The qucstion is**whdh~"I** 

### SC'R leclmology is "'applicable" lora unit fInng North Dakota lignite_

In accordance wim EPA's NSIl Manual, a technology is "applicable" ifit has been inSlalled On , "similar unit". Hot-side, high-dnll 

### SCR leehnology h" been retrofit on cosl-fjred nmls 

### fe'luring cycloneboik-rs. However, there are nO SCi{ inslallalions in operation or planmil onllJlils lhat include cyclone burners firing NorlhD<lkota lignite with severe .>Iagging and 10\lling tendencies combined with such high boiler economizeroutlet gas lemperarures**(o~cr** 

### 750'F) required for high-moisLure fuel prc-drying syslems and tubular air preheulors.

The 

### EPA's NSR Manua! al.>o slales a tec1mology JIlliy be detennined to be nol upplio"blc if**~a** 

### technical assessmenl consideringphysicul, ohemioal and engineeringprinciples and/or empirical data showing the teclmology would not workon the emissions unil underreview or !hattuloolvabletechnical diffioulties would prccludc the successful deploymenI ofibe lcclmique_" In 

### this SCR technology upplioation, it appears that a facil ity 

### ulility powcrplant firing North Dakola lignite would experience ""tende<llime delays orhe r"'luircd 10 

### devote significanlinremal reSOUrces "nd engage outside research, followed by 

### exlCllded field trials 

### to learn how 

### to apply a conventional high_dusl, hot-side SCi{ teohnology On 

### a snoh a fuel source.

Based upun this lechnieal assessment thaL looked at the v,rious design and operation"l issues "-SSoeiatcd with the in.>1aIMion ofhot-side, high-dust SCR technology on a NorthDakota lignile-fired sLcam--eleclric -- 

## :,

Bl1rn, & McDl1l1ncll Al-32 Squaro Bulle Ekcrrie CoOPCTIltiveAPPENDlXAI Technical P",sibilityAssessmen' Det:lils for NO" Conuol Technologic' NO"BACT Analysi' Study

generatingunit, this control option is considered technically infeasible for Unit 2'sboiler atMillon R. Y,mng Station.


### A.1.3.4.2 Low-Dust 

### Selective Catalytic Reduction (LO-SCR) Low-dust SCR (LD SCR) technology could potentially be applicable to North Damta lignite-fmd boilers for

### NO" emi,sion c"ntroL Low-dust SCR refers to the location of

### the SCR system d"wnstream ofa particulate collection system, such as an electrostatic precipitator

### or a fabric (iller. rfthe low-dust SCR is downstream ofa hot-side electrostatic precipitator and prior to lhe airpreheater, flue gas reheating is nnnecessary. This has been**~le** prevalent form ofallemative retrofit SCRs in theUnited Slates for coal" fired utilityboilers. There are ten known hot_side Jow-dust SCR installations (without flue gas reheat) operating in theUnited Stales as ofJuly 2005. These ore listed in Appendix A2. rfapplied to MRY Station UnitZ's boiler, the low-dusl SCR equipment wouldbe downstream ofa eold-side electrostatic precipitator; flue gas reheatprim to the 

### ill SCRreactorinlet would 

### be required forproperNo", emission reduction performance,

f'or a wId-side 

### ill SCR, the ESP outlct flue 

### gas passes through a low-<lust gas-to-gas heat exchanger 

### (ill 'GTG_HE), prior to passingto lhe low-dust SCRreaclor. Afterthe LD GTG-HE, the flue gas wj]] travel through the new duet; receivinghot flue gases from a direct-fired gas burneror set ofhigh-pressnre stearn coils, leading to an annnonia.injcction grid, turning Vanes and lllen into the LD SCR reactor. The flue gas

•enlering lhe inlet to the LD GTG HE is expected 10 bene:Jr lhc nir healer outlet temperature**(330-3~0"F)**

in a oold-side LD SCR application. 

### The supplcrnenl<ll heal added downstream oIllie LD GTG-HE can be supplied from high temperature steam eoils (indirectheal =hange) m directly from ualural gas-fired ductburners. The flue gas mustbe heatedto a minimum ofapproximately 600"F for the 

### ill SCRNO" annnonia reaction 10 

### be effeclive, TheLD gas-to-gas heat exchanger is used 10 recover part ofthat supplied heat, prior to exlmusting 10 the FGD syslem (ifapplicable) and slack The use ofrotary regenerative-type heat exchangers has been applied in European 

### ill SCRs. With this design, there will be leakage between lhe untreated and treated gas streams such that the exit flue gas has higherNO

### x concentrations lhan lhe LD 3CR outlet g;ls. The direct-fired flue gas rencat ductburners will also create No", emissions, whien will add to the amount emitted from the boilerand input inlo the 

### ill 3CRreactor. The 

### ill SCR reactor, 

### GTG HE, and connecting ductworkwiJl increasethe pressure drop through lhe flue gas system. This nonnally requires an induced draft fun upgrnde m 

### aboosterIan addition.

Square Blltle Electric Coop.rojj"e Al_33 Burns & McDonnellNOx BACT Analysis Sluuy APPENDIXAl Teehni""l Feasibility A."""men[ Detail, for NOx ControlTechnologies**---~-~---~--** The**[~eLon;** lhat make low·dnst SCR technology infeasible for !he Millon 

### R Young Slalion Unil 2's hoiler with existing purticulute collcclion via electrOSt'llic precipitators are as follows:

• Catalyst Fouling and Deactivatioo: An existing electrostatic precipitalor upslream of

### alow dusl SCR reaclor will slill expose the enluly,tlo Lhe acid gas conlent ami fine particulale conlaioing**l,~ce** merals andthe high**~]kali** mincral conlent oflhe entraiued lignilc llyash not removed 

### by the ESP up.,tream. Although the lola] amolJTIl offly",h carryover into the LD_SCR reactor is greally reduoed oompared with a high·dust design, ir is anlicipaled**lh~l** Ihe low-dust SCR catalyst IiFe will slill 

### be unacceptably short. The small particle flyash passing inlo lhe reactor will he sufficient 10 cause pluggage of[he catalyst pores, resulling in de"otivation of!.he catalyst. The firing oflignite coal produces fine (Ie", than 5-j.lm diameter) flyash p"rticks, which are**~Iso** leasl likely to be removed by lhe existing parnculale collection equipmenl (e.g. ESP) upstream ofa low-dusl SCR. This creates conditions lhat allow these small ilynsh particles lo enter the pores O(-lhe euLalyst, react with ,,0-, in the flue gas, and form suillito< which bind orher ash panicles into 

### a mulTix ofsodium-, cakium-, and sulfur-rich materials nikely in a fom:: ofculeium sulfale). Once suoh a matrix. forms within Lhe**catalys~** il can be extremely krmoious and difficult 10 remove_ One c·,tulysl vendor's has 'latcrl il 

### is**!h~';r** "experiellCC lhat low-dust catalyst is morC difficul! to clean than that [rom**high-dus~'''.** Low-du,t SCR ., performanoe und catalyst life could be severely neg.lively impacted_ Shortened lJfespans ofthe LD SCR ealalys! will require premature, eXlcndC<!, frequent outages for**replaccm~"[]l.**

• Sile Space Constraints: The insmllalion of" low-dust SCR syslem with flue gas reheat requires" subslantia] amount ofspace for installalion and operalion. A low-dust SCR sysrcm will likely use a regenerative gas_lo_gas heat exchanger (renearer) (0 raise lhe temperature oflhe flue g.s al lhe SCR inlcl. 

### A GTG 

### HE win trn.nslerheal from lhe flue gas at lhe SCRrcaclor outlello lhe flue 

### gas enkring the SCR reactor in onkrlo minimize the supplemenlal SCR energy usage_ The gas-to-gus heat exchanger**dicla(e~** the footprint oflhe cold_side low-dust SCll system_ Space is required for the GTG 

### HE and for ductwork in and oul orlhe rChenl<.T. Sufficient free space around the reheater and SCR is also required for maintenance.

The area around Unils I and 2 allhe MJL Young slation is cxtremely congesled in the areas where low-dusl SCR systems musl bc localcd. The situalioll is parricularly severe for Unit No_ 2. Equipmenl Ihul impacts the feasibility ofinslalling a low·dusl SCR system on Unic' 

### 1 and 

### 2 includes lhe Unit 2 absorbers, Unit2 flue**g~s** desulfurization (I'GD) dcwakring equipment, fly ash hsndliog equipmcnl, fuel storage andtransfer equipmenl, slrleks, fans and ductwork- 

### II wouhlbe extn
.. mely

Bum' & McDonnell AH1 Square Bullo Eloolrio CooperariveAPPENDIX Al Technical Feaslbilily Assessmenl

### Details for NO" Control Tecbnologic, 

### NOx BACTAnalysis Srudy

disruptive 10 the continued economic operation ofbolh boilers to relocate alllhe mentioned equipment to 

### creale space for the low-dust 

### SCR systems at the M.R_ Young Slalion. Stacks, fans and ductwork and lhe Unil2 FGD system eannOlbereadilyrelocated due to adjacent strucLures and lhe need to 

### eonlinue operation while construoling lhe retrofit inslallaLions. The fuel handling equipment indudes a cool stornge bam and the main conveyors supplying lignite 10 lhe unils. Relooating the coal handling equipment currently occupying space needed for the low dust SCR system:; wouldbe quite difficult given the site configuration. 

### It**i~** 

### conceivable that the fly ash equipm.nllooated west ofUnit I couldbe relocated to provide some oflhe spaoe needed for lhe low-dusl SCR. However, the uvailabilily ofthis space is doubtful, since avoiding the likelihood ofsevere SCR calalyst sulfale fouling will require a new Unil I FGD system to be installed. Ifa new FGD syslem is installed for Unit 1, lhe FGD sysLcmwould need to 

### occupy the space that can be Illilde available by re!oc:ating a,h handling equipment This space subsequently would nOl be available for low-dust SCR sysLcm.

Based upon a teclmical ass(\gsmcnt lhallooked at the various design and opemtional issues associated wilh lhe installation oflow-dust SCR technology on a Norlh Dakota lignile-fired slcam-clectric generating**uni~** 

### this control option is considered lechnically infeasible forthe MiHon R_ Young Station Unit 2's**boil~T.** 

### A.1.J.4.3 Tail-Gas Selective Catalytic Reduction (LO-SCR) A tail,gas (TO) SCR is a low-dusl SCR system where the 

### LD SCR reactor is installed downslrcam 

### oIa FOD scrubber. The FGD outlel flue gas passes througb a gns-to-gas heatexchnnger (GTO·HE), prior to passing 10 the tail-gas SCRreactor. The flue gas will travel through new or modified ductwork leading 10 Un nnnnonia injection grid, turning vanes and lhen into lhe TG SCRrcaclor. The TG SCR reactor, GTG HE, and connecting ductwork will increase lhc pressure drop lhrough the flue gas syslem. This norrnully requires an induced draft fun 

### upgrade or a booster fun addition_

A schemalic grnphic diagram for a low dust aITilngement is shown in Figure A.I"6.



### Square Butte Electric Cooper,live AI-35 

### Burl" & 

### McDonnellAPPENDlXAJ Techni,,1**f~",ibility** A"c"mcnllJelails Fo,· NO" Conlrol Tech'JQlogies
Figu.c A.1-6 Tllil-Gas SCR Arrangemelll 

# Low Dust Arrangement (1·\ S[eam genC"rator u

### I,,~) 

## Il.cgemralillgheat e,xchangcr 

# ,-, (:3,) Air 

# o F.lcctrostatic precipitator 

## (5) 502

-Scrubber (6) Burner! Heat behang"**~~** 

# ® SCR 

## ReaClor

(figure copied from Wheelabrdlor AU- PollUTion Conlrol lilcmlure)
TlJe flue gas from a 

### wet FGD scmboor ouUel enlering the inlcl 10 the gas-to-gas hcal**e~changcr** i,**~xpe<:ted** 10 be**n~~r** lhe saluralioo temperature (140"1') in cold_side TG SCR applicalion. The supplemental h"ul udded downstream ofthc TG GTG-HE can be ,uJl!llied Imm high temperalure sleam eoib (indirect heal exchange) or direclly 

### From natural gas-lired tlucl bumer.<. The**f1o~** 

# !':"' fUu,1 be heated [0 a minimum of**appro~imalcly** 600"1' fQr Ihe TG SCR NO" anHnonia rctlclion tQ be elTectivc. Thc TG gas-la-gas heat**e~c1wnger** is used 10 recover pari ofthftl sLipplicd heal. prior 10**exh~u'1ing** to Ih" 'l"ck. Wilh a rol"!)' regencrative-lype gilS-IO-gas hal exchangcr, Ihere ""ill be**illlem~lleakage** hetwccn Ihe unlreated "nd**Ir~aled** gas slreJJl1s such lhat lhe stack exit flue gas has higher NOx coneenlmlions than ti,e

Bum' & McDonnell 1\1-36 5",,,. Duer. Eleclric C(]U [>CralwoAPPENDIX AI TechniC<l1 FeasibiliTYAssessment Details for NOx ControlTechnologios NOxBACT Analysis Study

TO SCRreactor oullet glls. Using direct-fired llue 

### gas reheat ductburners will also creale NOx emissions, which will add lo the amount emilled from!hc boiler and input into theTO SCRreactor.

There is limited leclmical infonnation publisheli in English for coal-fired steam-electric generating units (SEGU) wilh low-dust/tail-gas SCR technology in applications requiring 

### full flue gas reheat prior lo 

### lhe reaclor inlet. There is nO experience with TO SCR on eastern bituminous, western subbituminous coal or lignite-fired SEGUs 

### in the Uniled Stules. As of1997, there 

### was one low-dustllail-gas SCRon a 220 MWe German cyclone-fired boilerwilh ;l 1988 retrofiL installalion. This boilerwas reportedto be operating; wilhout combustion controls orFOD, burning low sulfur, low ash, model"-te moi5ture bituminous coal with an averagc pre-SCRNOx emission rate ofapproximalely 1.07lblmmBtu, and was meeting a 30-dayrolling average emission limitofapproximately O.16lblmmBtu (85% reduction)".

Milton 

### R. Young Station Unit 

### 1 does not currenLly incorporate any flue 

### gas desulfurizalion eqnipmenL, which would place the reactor calalyst in a low-dust SCR confignration, which is considered infeasible when burning North Dakola lignite. A new FOD system for Unit I wonld 

### be required in order to avoid or signlficanLlyreduce exrected sulfate formation 

### wilhin the catalyst and gas-to-gas healexchangerwhen combined wilh ammonia required for the 

### TO SCR. Unit 

### 2 currenLly employs a wet scrubber which

,currently tIcats upproximaLely 83% oflhe tolall1ue gas flow from lhe boiler. Flue 

### gas reheat is currently provided by lhe FOD hypass (i.e. wann, unlreated flue 

### gas is mixedwith the cool scrubbed gas).

The faclors thatmake lJIil-gas SCR technologyinfeasible for bothMilton 

### R Young Stalionboilers with existing particulate collectionvIa eleotrostatic precipitators are as follows:

• CaLalyst Fouling and Deactivation: TheTO SCR reactordownstream ora flue gas desulfurization (FGD) scrubber "'ill still 

### be susoeptible 10 fouling, contaminalion, pluggllge, and calJllysl deaclivation.
o An existing electrostaticprecipItator (ESP) upstream of" tail-gas SCRreaclor win still expose lhe calJllyst to fine particulale containing trace mctals and the high alkaE mineral conlent ofthe entrained lignite Dyam nolremoved 

### by lbe ESP upstrealIL Allhough lhe total amount offlyash carryover inlo lhe TG-SCR reaclor is greally reduoed compared wilh a high-dust design, it is anticipated Ihatlhe lail-gas SCR <:alalysllife will still be uIDIcceplubly 

### shorl.


### o The firing oflignlte coal produces fine (less than 5-l-!m diameter) J1ya,h particles, which 

### are also least likely 

### 10 be removedby lhe existing particulale collection equipment (e_g. 

### ESP) upstream of

Square Btlne Electric Cooperative AI_37 Bums & McDolUlenNO" BACT Analysis Snldy APPENDIX Al Tcchnical FcasibilhyAssessmenl Details for**NO~** Control Tedmologies**~---~~---** a TG-SCR. Flue gas wilh entr"im<l finc particulale matter, including some involving sodium and sulfur-containing compounds, will pass lhrough and 

### be earried-over from a weI FGD scrubber. This tIculed g;Js "ITeam will carry souium sulllllC particles, formed by homogCIlous condensation after exiting lhe boiler andnol removedbythe FGD syslem, inlo the ealn]ysllayers ofthc TGSCllreaclor. A dry FGD sy"lem followed by a fabric filter up.o;tream ofthe TG-SCH will still allow sulfur-bearing nue gas and tine particles to enler lhe catalyst. There is seriolL' concern lhat fine parlicles pas"ing inlo the TCuclorwilluccumulale within the catulysl, and be resislanl 10 removal by conventional sootblowers and oilier cleaning technologies. This creates conditions !hat allow these small flyush particles 

### to enter 'he pores ofthe caWysl, react with SO, and/or So, in the flue gas, and form sulfaIe" which bind other a"hparticles inlo a matrix of"odium-, calcium-, and sulfur-rich**material~** (likely in a form ofcalcium sulfate)_ Once such a malrix forms within Ihe catalysl, il can 

### be extremcly tCIlacious and difficulllo remove. Calalysl thaI is exposed to such conditions will be ineITective al maintaining adequate aClivityupon which the performance of !he TG-SCR's 

### No" removal is 

### based.
o These cntrained particles will al"o deposil on me gas-lo-ga" heal exchanger ahead oflhe tail gas SCRreactor. TIlis depo.<ition will decrease heat transfer between the Illcoming (cool) nue 

### gas an<llhc outgoing (warm) fiuc 

### gas. Sootblowcrs could be used loremove lhe accumulated deposits from the GTG 

### HE, but lhe SCR reactor could still suITer catalysl fouling from lhe deposits dislodged from the GTG]-JE cleaning cycle becoming reentrained in the reheated nne gas. Tail-g;Js SCRperformance amI G;ltalysl life could be sewrely ncgatively impacted. Shortened lifespans ofthe TG SCR catalyst will require premature, eXlended, frequent oUlages for replacemenL

• Site Space Constraints; Thc Installation ofa tail_ga., SCR syslem Wilh fiuc gas reheat requires a substantial amounl ofspace for installation und operation. A tail-gas SCR system will likely use a regenerative gas-to-gas heat exchanger (reheater) to raise ilie lempero.ture oflhe nue ga., at the SCR inlet. 

### A GTG 

### HE willlnlllsfcrheal from thc nue gas althe TG SCRrc.cloroutlello the "crubbed flue ga" enlering the SCIl reactor in order to minimize the supplemental SCR energy usage. The 

### ll"""**to-ga~** heat exchanger diclales the roolprinl ofthe TG SCR system_ Space is required rorlhe 

### GTG 

### HE anu for duclwork in and out oflhe rehealer. Sufficient free space around lherehealL"- and SCR system is also reqllired forrrulinieffilllcc.

The:trea uround Unils lund 

### 2 allhe 

### M.R- Young stalion is extremely eongesled in the nrea., where TG SCR**sy~lems** mustbe located_ 

### A flue gas desulfurization sy"lem will be needed forUml 

### 1 in the

Burns & McDOJlllell AI-38APPENDlXAI Technical FeaslbHi,y AssessmentDetails'for**NO~** ConlroJ Tcclmologies NOx BACTAllilJysis Study

near future to comply wilh lhe ConsentDecree. When a new FGD syslem 

### is installed for Unit 

### I, the FGD syslem would n""d to occupy the space thaI can

### be made available by relocating ashhandling equipment. This spa"" subsequently would nol be available for a tail-gas SCR system. Thus, the availability ofadequale space for aU the new FGD and TG-SCR system cquipment and slructure5 while accommodaling**exis~ng** cool storage and handling needs for both el<i5ting boilers at Millon 

### R. y ollllg**Sta~on** is douhtful.

The challenges for install"tion ofnew ductwork, SCR reactors, and fluc gils reheating equipment aud the Jaok orpertinent experience with all 

### aspects ofdesign, construction, operation and maintenanoe oflail-gas SCRs on suchhigh-fouling coals as North Dakola lignite are signifioant. The flue ga5 condition5 that the TG-SCR calalysl will be exposed [0 will create unresolvable fouJing anll blinding U1a1ll'Ulkes successful application ofthis technology difficult, expensive, and uneertain_

The risk offailure anduncertainty ofsuccessfully applying low-dusl, l"il-gas SCR leclmology 10 a**oydon~-[lfed** utilitypowerplant firing Nonh Dakota lignite appe.ar substantiaL

Based upon a tedmical assessmenllhat looked at the various design and operalional issues associalC<l with lhc installation oftail-gas SCR teclmology on a North DakOla 

### Iignite-fired steam-electric gC1leraling unit including a cyclone boiler, this control option is con,illere<11cchnically infeasible for lhe Milton R. Young.Stalion Unit 2'5 boiler
### A.1.3.5 Eleetro-Catalytie Oxidation**(ECO~** Powerspan's Eleolro-Calalytic Oxidation (ECO'") system is a multi_pol1utlmtteclmology dcsigncd to oontrol emissions ofNOx, SO" fine particulate, mercury and certain Hll7.llroous AirPoliulanlS (HAPs). The ECO" process has two main process vessels, a barrierllischarge reaclor, and a mulli.level wet sombber. The barrier discharge reaclor ulilizes an eleetncal dischargeto create oxygen and hydroxide radicals whioh then reael with NOx, and olher constituents in the flue gas stream. The flue gas stream then enters the bottom ofthe ECO" scrubberwhere the lower loop cools the flue gas and removes a portiou ofthe acid gasses [sulfur trioxlde (SO,), sulfurio acid (H,SO,), nilric acid (ANa,)] produced in the balTier re.actor and oxidi7.ed melals such 

### as mercury, with a low pH aque<Jus ammonia reagent. 

### A second scrubbing loop is then enlered where additional SO" NO" acid gases and oxidized melals are n:movcd with 

### an aqucous ammonia reagent, (hough at a higher pfL Above the second scrubberloop is an absorber section for absorbing fugilivc ammonia from the first and second scrubbing loops. The final

Square Bune Eleclric Coopel1\live AJ-39 BUIIlS & McDonnellNOx 3/\CT**Ar.~lysis** Sludy APPEND1XAI Technic,1 Feos;bility Asse'SLnenllJetails for NOx Control Ttthnologies
step ill lhe liCO'" process is a wet declrostatic pC<cipitntor (WESP) which OOnCCIS**n~e** p"rticulale**In~\(er,** aero;;ols gencraled in tl:te scrubhcr and**~ddilional** mercury. An**upd~jed** schemalic process tlow diugmm for the b",ic**ECO~** process is shown**i~ I'igur~**  1\.1-7. 

### Figure A.1-7
- Electro-Catalytic Oxidation (ECO®) Process Flow Diagram (,"piou from "l'p'II,",",".'"' vuv!app,dw\Vwla"IM'PA600RmI10**od~** 

# ECO" Process Flow**r"rl""'~i"** __**~r~r" IJ'.,,----,:~_**  

### r",""**~.r"** . .**~- l'.\~J**  '**~"'** .'



## ,i·o ; 

## , "
. 

# LJ



# ,**:r\:!,~** 

# -

# ""'"**,,~ ,~** 

.. ---- -_." I**~f)"** 

### /11""'''' ·'1 ,",,,,

- - h 

### ffU**R"~UDr** 

# I ".' 

# , , Ab."r.. VOI",I 

# i
.....**~"** 

# ,,,;," (';.;'N**WetE~P** 

# L r----;;:: 'L%,' Co·Pm'lI:l ROOlV1ry' 

## "orr••

# _.

... '"

l'owerspan htlS been involved in an extended ECO'" process**dcmonslmlio~ lL,i~g**  a 

### 28 MW Commercial Demonstration Unil (CDlJ) at 

### R.I'.. Burger Station Unit<; 

### 4&5. 'lbe ECO<!l CDU project treated slipslream and demonSll"alCd performance, reliability and economics for approximalely**on~** year. The demonSlraliun program ,larled in Janllaoy, 2004. NOx removal i" ,taled to be up IO 90% wilh a c1aimcd 0.05 lb NOxfmmBlu**out1~r eomlilio~** **achievabl~** lor the front-end orthe ECa" pmcc.'.'. I'mthec su,lained operation"1 tesls orille ECO''' CDU are underway during lhc second**a~d** lhird quarter' 0[2005.

As 

### Ihis is a post_combustion muiti-pollulllniconlrol technolugy, il is claimed thal there i, little ;;cll.itivily to the 'Ype boilel' or burners lhal l'owerspan'< Elcciro-Catlllytic**Oxida(io~** CECO") process can be
BIH'ns & McDonnell A 1-40 Square Dune**Iij~c!l;c** C"nrerotiveAPPENDIXAI TechnicalFeasibilityAssessmentDetails for NOx Coolrol Technologies NOx BACTAoalysis Study

potentially applied to 

### in order 10 reduceNOx emissions. Tho effectiveness ofthis ECO'" process for NOx control has been demonstraled on a slip.slream commercial dernonslr"ation unil (CDU) associated with pulvcrizc<l fud boil= firing midwestern oreastern biluminous coaL
Powerspan's published data from tne commercial demonSlration unit'sperforrnance ofup 10 90% when treating l1uo gas wilh an inletNOx concentralion around 

### 0.5 IblrnrnBlU. This would resulL in a stackNOx emission around 0.05 IbfmmBtu.

The ECO'" process has nOlbeen demonslr"ated in a full-scale configuration on anyunit, nor tesled in a slipstream configuration onany boiler lhat fires weslern subbiLurnlnoliS coals 

### orNorth Dakota lignite. 

### Il has also noL been applied 10 emissions .from a cyclone-fired boiler. According lhe EPA's DmfiNSR Manual, ',echnologies which have not been appliedto (or peffilitted for) full scale opernlionsneednot be consiclered available: an applicant sbouldbe ablew purchase or construct a process or wntrol devicetbat has already been demonstrated in practice".

There 

### are a number ofissues wilh firing North Dakotalignite lhat make the applicability oflhe ECO'" process lcchnically infeasible for

### MRY Station boiler,. These issues include:

• DeposiLs and Plnggage: The l1yash deposition characleristics oftheNorLbDakota lignite lire extremely severe. Anything that contributes 10 J1yash deposition and pluggage wilhin the barrier reactoris expec[Cd tohave a detrimenLal impact onthe multi_pollulant control perfonnance oflhe ECO'" proccss, and lhus could have a serious impacLon MRYStation operations. The lack of demonstraled operntion en lreatingthe emissions from a boiler firing coal with a high slagging indexprecludes the use oftheECO"'prooess 

### as technically feasible for BACT

### as applied to a boilerfiring NOI1h Dakota lignite.

• Reliability and Availnbility: MiUonR. Young Station's major plannedoutages foreach unit are scheduledto 

### occur once every three years. Any NOx conrrol technology selecLed 

### as BACfwill need to operaLeycar-round, year in andyearout, on a routine basis, while performing at high levels ofpclluLant reduction. The Powerspan ECO'" system is a new technology and 

### Is nOLas highly developed 

### as olher more commonNO

### xand SOo control teclmologies suoh as SCR or SNCR plus wet or semi-dry flue gas desulfurizalion (FGD). 

### It is expecledto require a full-time, full-scale applicalion wilh sustained conlinuous operation to confirm levels ofcurrently demonsln!ledreliability and availability from lhe ECO" COU are acceptable 10 meetthe
Square Durte Electric Cooperative AlAI BIlfIl' & McDonnellNO"BACfAnal}"'i' Study APPENDIX Al Teohnicnl FeasibilityAssessment Dotail' for NO" ControlTeclmologies
expectuLion ofinfrequent**m~jor** OUl"gcs**OV~T** long time periods while maintaining high levels of control.



### lbere are addillooal futon; that make Ihe appliealiOn ofthe ECO'" process potenliallymore difficnlt !han oIher cSlabli,hc<! cmission control technologies available for coal_fired powerplanls:

6 Thcrc is a lackofc"pcricnoc with lhe 

### ECO'" downstream ammonia scrubber's coprodnct crystallization and grannli7.ation equipment design, opcmtion, and m"intenanoe, whioh was not inclnded with thc initlal commercial demonstmtion unit. The coproduct stream thst wonld nOTlll"lly feed into the cryslallizalion and granulatiOLl prooesses w,", colleded and tr.msported offsile for this process slep dnring CDU operaliun. Bcoausc**cryslalIiza~on** and**gr.mula~on** of ammonium sulfale from an ammonia scrubber**solu~on** is not a new technological process, this
was nol considered a teclmical feasibility deficiency_ For instance, Ihe**Dakot~** Gasilic"tlOn Company (DGC) in Beulab, ND cnrrCnlly**operntc~** an So, scrubberntilizing ammonia as a reagen!. Following the generation ofammonium sulfale, DGC crystallizes and granuMes a fertilizer product on sile_ I [owever, at.MRY Slrllion, eon,iderable costs wonld be incurred for inlcrimstorngc Hnd shipmmt ofthe ECO"'process >emhber'sliquidbleedstrelm unlil**~ufficieut** experience has idenlified and eliminated potential failures and rcP"ir5 for the oryslallization and granulation equipment should itprove to be unrcli"blc.

• Size ofthe barrierre"ctor: Powerspan recenlly indicared that they 'Vonld scale lhereaelor for optimum cost and spaoe arrangement based upon**k~~uns** learned from the CDU plant operation. The nnmber ofindividual passages within a barrierreaclor sized for eithe,· ofMRY Slation boikn;' maximum fiue g<lS flow and gas stream oonstitnenls is expCClCd 10**r~'"<Iuirc** a crossseolional area comparable to halfofa large eleelroslalieprccipillolor. Although this has nol been dosely examined lor all aspects ofdesign,**eon~truc~on,** operation and mainleoance, the amounl ofphysi""l space reqnired to hold the barrier reactor and inlet and oulle! ductwork is believed to not be available for potential retrofit

### to MRY Station units. Sile space oonslmints are considered to be a barrier 10 tec!mical feasibility for potential**appljca~on** ofthe ECO"'prucess al Millon R_ Young Slalion for Unit] and Unit2's boil""s.

6 Additionalstalion auxiliary powerconsumption: The barrier reactor, pins the mnmonia**s~'rubber** and wet electroSlalic precipitator additions by**~n** ECQDl syslem, require an increase in station 

### , 

## ,

Bums & MoDOlUle]j AI-42 Square Butte E1ectrio Cooperalive

-

### APPENDIX Al Technieal Foa'ibility Asses.,mentDetail, CorNOx Control Teclmologie.s NOx BACT Analysis Srudy

auxiliarypower consumption. ForNOxcontrol, (his includes more horsepower required by thc boosterfun needed to cOIIIpCI!sate for the flue gas pressure drop created across thebarrierreactor. 

### It also includesthepowerconsumed by the electrodes ofthe barrier reactor itself.

Because ofthe technical feasibility issues and lack ofwmmercial availability and full-scole experience, especial\y on such high fouling coals, the ECO" system 

### was considered teohnically infeasible as a BACT nllematiw forMilton

### R. Young Station for Unit2's boiler.


### A.1.4 "Layered" NOx Reduction Technologies**~'"'** 

### Many ofthe NOx emission reduction teclmologies which involve furnacc or convection pIlss arcos for theirinlroduction into the flne gos streamhave been, or can potentially be, oWEed in combinations so os to resnll in an overall higher level ofremoval. Separated overlire oir, various types offuel reburn, and various fonns ofSNCR could polentially be combined in series to 

### reduce NOx emissions prior to boiler's flue gas exit. However, alllhe possible NO" control technology combinations havenotbeen installed on "Goal-fired poweIplants, so acmol feasibility ofsome combinations hove not been demonstmled as viable, -particularly in considemtion ofthe special challenges posed bycyclone boilers firing lignite coaL



### A.1.4.1 SOFA Combined With Other NOx Reduction Technologies Scparated OverfIre Air COIl 

### be favorably combined willi every othermcthod in order to reduce the amount ofreagenl nrrebum fuel required to achieve the resulting level ofNOx emission reduction. Some wntrol teclmologies, especially conventional fuel rebum systems, require overfue air (0 complote the combustion of

### the staged fuel admittedto**~le** 

### upperfurnace. Fuel lean gas reborn can be applied withorwithout SOFA, as this limited amount ofstaged fuel is introduced into an oxygen-rich atmosphere downstream of tile cycl(Jj1eburners and any ovemre air injection points_



### A.1.4.1.1 SOFA with SNCR Selective non catalytic reduction teclmologies are post--combustioll, iu-furnace NOxcontrol alternatives thalhave been installed in nUmerous boilers ofvarious designs, fuel types, with and without overfire air. It 

### is usually advantageous to apply overlire air so thai the amount ofchcmieal reagent consumption can bemiuimized in order to nchicve the largcled NOx emission mte from the boileroutlet.

Square**B~tlo** 

### B<:clrie Cooperative AI_43 

### BlITIlS & 

### McDonnellNO"BACT

### Analysis Study APPENDIX Al Technical Fca'ibili<yAssessmenlDelails for NO" Control

### Technologic,

Tesls at Conectiv's 

### B.L England Slation (Units 

### I nnd 2) demonstrated lhat SNCRcnn decrease NOx emissions as much us 31% ut full loud, from 0.55 to 0.38 

### lb!mmBtu, over and above the reduction possible from overfire air alone (approximately 60% drop, [rom 

### I.J to 

### 1.4 downlo 0.55) 

### in 

### full operation. This is an overall NOx emission reduction of72% from pre-retrofil baseline".

SNCR canbe "pplied alone Of 

### combined wilh either the baaic or the advanced forms ofsepamted ovcrfire air (ASOl'A) on MRY SLalion boilers. Air-slaginz thc cyclones wilh lhe use ofseparaled ovemre air 10 

### further complement combustionNOx

### reduclion is an optional part ofthis lechnique. However, as previously explained in the discussion ofSOFA allemalives, Ihis Will risk slag "freczing" in lhe burrels and lower furnace. Estimated NOx emission 

### rote.s for using SNCR lechniques with North D"kota lignire considcred publiahcd levels achieved by cyclone-fired units firing we.,tern subbituminous 

### coal, and vendor ealimates. SNCRwith ASOrA is expected to reduce 

### NO:.: emissions approximately 32.6% below NOx levels predictccl for ASOFA opcmlion, nnd**pOl~"Illi"Jly** 

### 5B% overall from current baseline level [or the MRY Slalion Unil 2 boilerwith nmmonia slip limited to approximalely 5 ppmv<!. Ths highcst performing basic SNCR system is polcnlinlly able to uehicvc nNO

### x emisaion rale ofO_330 IblmmBlu, whcn combincd with!hc "dvanccd form ofSOFA on MRY Slation Unit, 2 

### bDiler during operullon at lhe pre-mntrol baseline (near MCR load)_ These levels ofNOxrc<!uclion d.p<-nd on the advanced [om, nf 

### scpnroted over-fire.ir technique lo achieve lhe expected NOx 

### reduction percentages when applied (0 

### lignite-frrcd cyclone boilcrs_

Anolher- [orm ofSNCR is combined with sepamted overfire air_ This is currenlly being mar"kelcd commcrcially as "RotatingMwug" (Rotamix). 

### In the Uniled States' utililies industry, lhis has only been "ppli.d lo pulverized coal-fired boilers. It 

### is different lban basin SNCR iu thalitiucludcs" hot airbooster fall and a small ambienL air fan, and injccts lhc mrrnonia (orurea) Te"gent 

### into the high-pressure ovcrfrrc air now stream ahead o[lhe ROFA nozzles' outlels. This mixture is imparted into lhe boiler

### in an olTset fashion from opposite sides ofthe furnace at high velocitie.', wilh multi-porlnozzles loculCd nl high elevations relative 10 

### lhe lop bumcrrow. Ths vendor (M:obolec USA) claims lhal Rotamix (rOLaLing opposed 

### fire air 

### or ROFA

## +SNCR) helps 10 

### distribute the reagent across the furnace cross scdion. which maximizes in-furnace NOx reduction while minimizing neg;ltive impacts on carbon monoxide and flya<;h unburned carbon_ Three tangenlially-fired ulilltyboilers burning easternbituminous coal urTIlinois biluminous coal were retrofil1ed wilh Rotamix, each achieving a NO

### xreduction ofapproximalely 7-"ro to 

### 55 percent beyond the levels produced by 

### ROI'A alone, frompre-SNCRbaselincs ofO.22 10 

### 0.28 lbfnnuBtu down lO 0.10 10 

### 0.23 lb!mmBtu wilhout low-NO"**hl1mers<'''~'~·.**

Bum., & McDrmmll ,1.1-44 Squaro Bullo 

### Elcelric CooporaliveAPPENDIXAl 

### Technical Feasibility Asses,mentDelails for NO" Control Technologie, NOx BACTAnalysis Study

While this variation ofSNCR combined with separated overfrre air could polcnlially be applicabie to 

### cyclone boilers, ithas norbeen IIIllTkcled (0 servc such applications_ Since cyclone boilers do nol require !he addition ofhot airbooster fans for SOFA, and optimum**inj~"Ction** 

### locations forbolh SOFA and SNCR reagent may not coincide, Rotami" may not perform as well as,

# or significantlybetter than, aweBdesigned combination ofconvenlional SOFA and SNCR. This**ledmiqu~** 

### is not distincl enongh from basic SNCR from fimctionaJ and air-staged cyclonc NOx rednotion performance standpoints to warrant individual consideration for Mihon R. 

### Young Stalion boilers. Because ofa lackofcyclone-fired boiler experience wiili ROFA and Rotarni", the latter wos considered**inf~a51ble** 

### and thus was notincluded in the control effectiveness and cost-effectiveness sections ofthe main report.



### A.1.4.1.2 SOFAwithRRJ Rich ReagentInjection must be used in an oxygen-deprived atmosphere in order to effectivelyr.duoe nitrogen oxidc emissions. This requires air-staged cycloncs and scparatedovertire air opemtion_

.The NOx emissionreduction reagent injection forRRl prooesses must beprecisely located andcarefuHy controlled to be effective. Operation outside oflhe reqnired opernting ranges can evenTCSU](in increasod NO" emissions_ Extensive oomputationall1uid dynamic (Cl'D) simulations are needed 10 determine the oplimuminjectionpoints. Boiler operating conditions wIll chang<: wilh unit loadand varying 

### fuel chamcteristies. TheRRIprocess control systeJI15 must be able to adjust for lhesc changing conditions.

RRlhas the potential to provide a moderate degree ofNOX reduction on coal-fIred boilers. Data from 

### B.L England and Sioux plants show this tedmology canreduce NOx emissions**betwe~n** 

### zero and 39 pereent bcyond lhe amount attributable to overIlie airsyslcm**operation"~',2<"~,,.** 

### During initial demonstration testing ofRRI at Arnerell's Sioux Unit I boiler, a 500 MW unil fIring a blend ofPRB and midwestern bituminous ooals (wiilioul SNCR), with 

### SOFA in August2001 at a lower furnaoe SR of approximately 0_99, NOxemissions Were rodueedapproxirnately 55% to 0.55 Ib/mmBtu 

### wISOFA only, with =0 to 

### 15% additional NOx reduction fromRRI (down to 

### 0.47Ib/mrnBtn) wilh zero ammonia slip", Results ofthis initial RR1 testing ot Sioux plantwere poor at cyclone stoichiometric rtllios elose Lo 

### 0.99 beoause**ineonsisten~** 

### sporadic, and non-repeatable NOx emissions reductions between zero and 15% were m=ed. SubsequentRRI testing at Sioux Unit 1 in March 2002 with SOFA at an average cyelone stoichiornetrio mtio aroood 0.95 showed NOx emissionsreduction of29 percent (down to 0.27 lb!mmBtn) beyond those achievedwith a modest amount ofcyclone air-stagingwiili SOFA (68% drop down to 

### 0.38 IbfmmBm from SOFA alone), for an 80% overnll decrease from Illlcontmlled baseline; RRI CFD model Square BUlleElectrio Cooperative Al--45 

### Buros & 

### McDonnellNUx BACT Analysis Sludy APPENDlX AI Technical FeasibilityAssessment Details [or 

### NUx ConlfolTechnologies
predictions for these eondiLions were NOx emissions reduclion of31% wilh FGR and 37% withont FGR operalion. TesLed NOx emissions with RIU+SOFA in 2002 were with a reag",",1 nonnalized stoiehiomelric ralio (NSR) on (lbs 

### NH) pcr Ib 

### NOx)"_

Purametrie lesting al Sioux. DniL 

### 1 in May 2005 reduced 

### NOx emissIOns between 15-38% with 

### RRI, down to 0_15 10 0.20 IbfmmBlu. Reagent NSR l,etween 1.0 and 4.0 and low ammonia slip**level~** less lhan 2 ppm from an estublished baseline eondilion of0.2.0 to 0.2851bfmmBtu level achieved 

### NOx emissiom as low as 0.12 Ib/mmBlu with deep cyclone air-slaging and SOfA**opera~on** Ilring an 80;20 PRBlIllinOl' coal blend at 480 MWgunit outpUl"-

"lbe intent offhe RRIprocess for NOx reduction is that ilmusL be used in conjunotion wiih nir-sLarved (substoiehiDmetric staged_air) cyclone oombuslion re""lting from the mslallnlion and operation ofan 

### OFA system, wilh or without 

### SNell The cyclones' air/fuel :;Ioiehiomctry mustbe carefully conlrolled to maintain fuel-rich condilions for the RR[ prooess IO be eITeGlive. The combll:;lion goJSCS in the vicmity of Ihe RRI Ure" injection ports mu:;lbe essentially devoid offree oxygen, in order to avoid oxidizing the nitrogen "ontuined in Ihe injeoled reagent, which wilJ increaseNOx emissions_ for 1ignite-fired cyclone bOJlers, Lhe ba"ic form ofseparated ovedirc**~ir** (wilhoul relocated Ugnite drying system ve"t port,) " inconlpatible with RRJ. Reagent injection 

### will be near 'he elevation oflhe existing lignite drying system vent ports in the lower front and rear walls ofa lignite_fired cyclone boiler located immedialdy above Lhe top row:; ofcyclones. These vent ports are located conGuITenlly with the existing flue gas**recircula~on** (FOR) poris on Unit 2'

### sboiler. The oxygen introdnced with the lignite drying system's venled moisture_ laden airstream, will cau:;c lhe urea 10 be oxidized, creating 

### NOx emissions.

The advanccd fornl ofSOfA relocates Lhesc lignite drying system ventports from the lowerto lhe middle fUIrulce, enhancing lhe desired**in-fum~ec** nitrogen oxides reduction process. Therelore, in order for RRI 10 be even moderately clIcc\ive in 

### redllcing NOx emissionB from a lignile-flred cycloneboiler, this ledmology mlls! be combined with an ndvanced form of**separat~d** overfire air, whether instal1ed with or wilhout SNCR.

As mentioned in the feasibility disclL<sion ofapplying**~~1>'ffilted** overfire air IO ligrritc-[=-cl cycloae boilers, lhe degree to whioh each and**~very** individual cyclone furnaoe Con bo suocessfully opernted wilh less than theorelical (substoichiomctric) combustion air dircclly im]Xlcts polential 

### NOx formation ""d further in-furnace emission roouclion. Becausc 

### the heat content ofJigrrilc from the Center mine i:; not '. "

Burns & MoDonnen /I lAC, SG"OTe**Bl1~e** Eleclrie Coop,,,,,iveAPPENDIX 

### Al Technical Feasibility Assessment Details fotNOx

### Control**Tech~ologies** 

### NOx BACfAnalysi, Study



### L. consistem from hour to hour, there can be**sub5tan~al** 

### deviations in nirffue1 ratios for individual cyclones from the overall average.


### In the case ofMRY Station boilers, Minnkota has simullllncously sampkd 1he unprepared lignile feed 10 

### several cyclones' lignite drying systems in order

### to detelllline lhe variability in (he combustible and ash componenls of

### North Dakola lignite. This invesligation found that 

### fuel qualily variaLions can resull in individual samples' heating values 

### to have a maximum differential ofover 12% of!.hc lignite samples' average. 

### TABLE A1-1 - Lignlle Heating Values and Variations for Milton R. Youn Station Unit2
M.R. YonngSllltion Differences Betwren Individual Individual Cvclone Lignite Samples Cvclone Limite Samoles HigherHeating Values, Percentage of 

### HHV**Differen~al,** 

### Percentage of 

### Brullb Average lillV 

### Brullb Avera eHHV Minimum HHV: 5,852 88.9% Minimum: 4 

### 0.06%



# -- MuximumHHV: 7,101 1.08% Maximum: 797 12.1% AverageHHV: 6,584 100% A vernge: ] 65 2.51%

_

## .. '- 

### When operating 

### with air-slaged conditions associated with separatcd overfrre air, any individual cyclone with

### lignite heat inpnt Jowerthan average can allow significant amounts ofoxygen 10 

### oxidize the urea c;,._ 

### reagent at high lemperatures, lhll5 increasingNOK emissions in thatzone al that time. Cyclones with lignite hentinputs higherthan average would produce lower stoichiometric air/fuel ralios and less NOx emis..,ions. Less complete combustionin the deeply staged cyclones may release insufficient nmoUIlts of hcal, lhll5 lllising the risk ofsolidiJYing lhe fuel ash so that it aceumulales within lhe cyclone barrel. This could 

### result in firing auxiliary fuel oil or takingthe boiler out-of-serviee toremove the pluggage. Nellhcr ofthese conditions is**~esirnble** 

### becanse theyresult inincrenscd emissions, lowerperfonnance, and higher operating costs.

The 

### MRY Station Unil 

### 2 boiler's cyclone air/fuelrntios varyin real·time ba>ed on significant changes in combuslible coment on an individnal cyclone by 

### cyclonebasis. Adjustmentofindividual cyclone combustion air inputs 10 

### compensate for lhe variability in individual oyclone 1ignile heal inputrales for Unil 

### 2'

### sboilerwould be neoessary to maintain consislent substoichiometrio opernLion ofovery cyclone during air-staged combustion. This places greal emphasis on achieving tight control over the air/fuel

Square Bulle Electric Cooperative AI-47 

### Burns & 

### McDounellNO"BACTAu.ly';, Slmly APPENDlXAI Technical Feasibilily A"c.."IlCnlDelalls for NOx Control Technologies

r"Lio.< on each cyclonc during air-sUlgcd combustion opcmLion in orderfor ASOFA 10 bc suoces..,ful in producing ,ignificanl additlOnal NOxemiS5ions reducLion on lignite-fired cycloneboilers.
Tl,ere lS no eqll1pmenl a\'flilabk for ooal-fired bOIlers Lhul e"nmeasuTC the fucl heat mput at the prepared feed injection poin! on such a ",riahle fuel 10 allow the determinalion ofrea,onably occur.llc air/file! ratios on individual cyclones in rcaltime. Wilhoul being able to**m~aSurc** the cyclone air and heat inputs Lo allow for conLrul ofair/fuel proportioLls and emissions, the sLoichiometric ratios ofindividu"l cyclones
can not be eslablished accuraLely 10 produce combuslion proUlICts e",cnti"lly devoid offree oxygen_ This**TCqujr~ment** is e-<:pecially necessary when employing RRI to avoid increasing, ralher than reducing, NOx emissions on thc MilLon 

### R.. Young Slalion ULlit 2 boiler.

Rue**g~s re~iT~lIla!ion**  in MRY Stalion Unit 2 boiler's lower furnace could increase NOx emissions by admitling**oxygen·be~ring** nue gas in the ,-icinity ofl.he injected urea ifRRI were appJioo with basic or advanced forms ofSOFA_ To avoid this negutivc unpocl, FGR in (he lowcr furnace would needto be discontinued. T1,ere i, uncer1aimy whelher modification or elimination oflhe lise ofFOR in the lower**fumac~** ofMRY**SL~tion's** Unit 2 boiler could be successful in controlling lower furnace wall fIrcside ash**deposi~oll** and gas temperature".

Because oflhe significanl msumlOunlable problems discu,-",d above which would increase NOx emi,-,ion rates, Rltl is cilllsidered tec1mical1y infeasible for**applio"~on** On (hc Uni, 2 cyclone boiler at the Milton R. Young Station.



### A.1.4.1.3 SOFA with RRJ and SNCR Wheo RRI is combined wiU, separated overfire air and SNCR, ithJS demonslrated very high NOx emissiol1s reduclion at Conecliv'" RT_. EnglandUniL I boiler cluring shon-Icrm lesling firing e"-SLem bituminous coal, on the ordcr of80% from an uncontrolled 1Ja.eline around 1.21bhnmBlu". InMay 2005, testing RRI+SNCR+SOFA at Ameren's Sioux Unit I boiler firing a high PRB·blcnd coal demonstr.lted NO" emission. as Iowa. D. 12 lb/rrnnBlu. This W3" from an eslablished baseline oon<lition of0.20 Ib/mmBtu level achieved wilh deep cyclone air-staging and SOFA operation. Thesc lesting resulls when firing- M 80%:20% PRBJlI1inois coal blend at**~80** MWg unit outputwilh a reagenl NSRof4 Md ammonia slip limited to Jess Ulan 5 ppmvd, showed M overall 90% reduction with no apparent ndvcrse ,horHerm impacts ofdeeper air-staged combustion lO!,'CLherwiih overfrrc air, 

### Rlti and SNCR applications"

_ Bums & McDonnell**AI--4~** SGu.re Ilune Eleclrie CooperativeAPPENDIX Al Technical Feasibili,y Assess"",nl Details for NO" Control Teclmolog;e' NO" BACT Analysis Study



# _. Be"ause ofthe significanlinsurmounlable problems regarding RRI as mentioned above, 

### RRIwith SNCR and ASOFA is considered lechnicaJlyinfeasible for**arrlica~on** on the Unit 2 cyclone boiler at thc Millon R.. Young Slation due to lhe variable heat content ofthe lignite fuel l'lhich allows thc creation ofoJ(ygenrich conditions in thc boiler.



### A.1.4.2 SNCR and Reburn SNCR could polentiaJlyhe installed downstream ofseparaled overfrrc air nud various types offuel reburn, to reduce NO

### x emissions priorto a boiler's flue gas exit. Several oflhese examples were already**dcseribed'~"·IO,II,l"'.l<.** Conventional gas (CGR) or coal reburn syslems, by and large, havc uol been combincuwith forms ofSNCR, although alleast onevendor (GEEnergy) has promoted a combination of conventional gas rebum 

### with SNCR and overfirc air systems 

### as "advanced" gas rcbum. Duly one example ofpermanenI installation ofSNCR wilhconventional gas rebum (and ovemre air) on a tangentially-fired boiler was found in available technical literahIrelO and vendor experience lists". The vendor (GEEncrgy) that provided the advanced gas rehurn system at 120 Jl,.fWNRG Somersel Stalion claimed NO" emissions were reduced

### by**~~%** from 

### a baselinc of0.45 down to 0.25 IbJrmnBtu with overfrre air alone; an addilional reduction of20% resulting from conventional gas rebum with overfrrc air, down 

### to 0.20 IbfmmBtu; and further decrease of45% downto 0.11 Ib/rmnBtu using gas rebum wilh SNCR 

### with an unstalcd amount ofanunonia slip, for an overa]] reduction of75% from uncontrolled baseline".

No examples ofactual demonstmlion orpeTIrulnenl installalion ofSNCR wilh conventional gas or coal rebum (and ovcrfirc air) on cyclone-fired boilers were found in a search ofpublished and proprictary technicalliterahIre. The lack ofexperience wilh lhesc combinations on 

### a cyclone-frredboiler, especiolly for lignile·firing, makes lhe application for 

### :MRY Station'sboilers infeasib1e_

FLGRY>< has been inslalled 

### with SNCR forNOx emissionreduction on several pulverized coal boilers, as 

### • discussed in the following subsection_ A polential advanlage ofFLGRTM over conventional coal or gas rebum lechniques is Umllhe fonrrer is genemJ1y companole with, but does not require, the installation and operation ofSOFA.

Rich Reagent Injection would appear 10be less capable ofbeing combined wilh fuel rebum, especially conventional fuel reburn alternalives with high amounts ofrebum fuel injection. This is due to lhe Square Butte Electric Coopomuve AI-49 Burns &-McDollUclJNOx llACT**A~,lyslS** Smdy APPENDIX Al Technical Feas1biliIjlAssessment Delails forNOx Control Technologio,
expected need 10 idle (e.g. not fire) up 10 four orlhe twclve cyclones when operating lherebum syslem al fUll boiler**lo~d.** 

### In this case, Ihc cooling nir inlroduced inlo lhe idle cyclones, nmJ**~ny** conveying air injectedwith pulveflzcd ,eburn coal (or ifnatnral gas is injected with recirculaled nue gas), are expected 10 cOlmlnact the fuel-rich c{)nditions ofthe air_and fuel--staged cyclones operating sub'lo;chiomelrically. This will couse a porlion oflhe "mine reagent to be oxidizcd in Ihe**low~T f"m"~e,**  crcating NO" emissions instC<ld ofconverting them 10 nitrogen ann water. No example ofactual demonSlrnlion or permanent in,tallation ot·RRI wilhrcbnm (and overfil-e air) on cyclonc-firet] boilers wus fOlmd in "v"il"blc lcchnical Jitcntllre or vendor eXjJel'lence lisLI. This oombination is considered infeasible due 10 lhe location ofinjeclion and variable heat contenr ofIhe lignitc rebum. fucl whioh allows 

### the creation of oxygen-rich conditions in vicinilY ofRRI injcctor,; 

### in the lower flml"CC ofUmlZ's boiler.
Hydrocarbon-enhanced SNCR (e.g. NOxSiar"") may potentially be combined with alllypes and forms of rebum previously dj,o\lSse<!, sinoc thc location ofmc cnh"ncoo ammonia injeclionnozzles will be above (hcyonu) the clevation in thc middlu fumace where any rebum fuel should be reaoted. No example of actual demonstralion orpennanent in.<tallation ofHE-SNCR wilh rebum (aLld overfire air) On "ny coa1_ fired ulihtyboilers, especially oyGlone-fircd unils, 

## '"D" found 

### in avoolablc lcclmical htCIll(ure or vendor**UXP~TIcncc** lists. Thc adv"nlab'C th"l HE-SNCRpresents is the potenlial for grealer-than-SNCR_levels of NOx reduclion without siguificant amounts ofgaseous hydrocarbon being required. Because ofa Jack of ,"" experience wilh HE SNCR applied to cyGlone boilen;,**~ml** nun" with significnnl mIlOlmls offuel rehum, this combination has not been invcsligaleJ further, and was not included in the control and cosleffectiveness analysi, for NO" control>.


### A.1.4.2.1 Amine-Enhanced FLGRTM (AEFLGRT"') or FLGRT'" 

### + SNCR Fuel_lean gas rebum has been combined 

### wilh SNCR as" hybrid form of"mine reagent teclmologics on al leasl fivc pulvcrized coal-fired lllility powerpJants retrofit inslallatious within the United Stat",. This combination oflechnologies allows the boiler

### to be operated with l'LGR""" alone, FLGRTM and SNCR simullm1eously, or SNCR only (wilhout SOFA) for the specific level ofcontrol desired or required.

No examples ofactual deffionstralion**orp~TIrulDcnl** insl"lIaliun ofFLGRThl 

## + SNCR (with or withoul overfrrc air) applicdlO" cyclone-fired boiler were found in available leohnicallllcrature Or vendor experi<'-"TICe lisls. The vendor Wuel Tech) that provided the AEFLGRThI syslem at M<'-TCeT Sl,tion claimed NO" emissions were reduccd by 60% (from a baseline of 1.4 d01NIlio 0.56 IbJmmBru) with 5 ppm ammonia slip wilhoUl over-fire ,ir. A technical p"pcrprovide, more details". Another Icclmic"l paper
Burn, & MoDormdl i\ I 50 Square**Bu~o** Eloemo**CoOper.l~ve**APPENDIXAl Technical FeaslbiIi<yAs,essmenlDetails for NOx ControlTechnologie, NOx BACfAnaly,is Sludy

slated Ihatl'LGRThl alone onlyreduced NO" emissions approximately 

### 27% from the 

### IA lb/mmBlu baseline, down to L031b/mmBlu".

An AEFLGRrM system (with or without SOFA orASOFA) may bepotentially applied 

### to a cyclone-fIred boiler_ The high capital and operating cosl, associatedwith applying fuel lean gas rebum is expected to make lhis economically unattractive, and the exisling lignitepre--<lrying vent ports wiillikely limitlhc NO" emission reduction potential ofthe FLGR'M componenl ifinslalled wilhoutlhe advanced fonn of SOFA_ The lack ofexpeIience with this combination on any cyclone-fired boiler, especially for EgnilefIring, 

### makes this combination infeasible 

### for:MRY StationUnit 

### 2 boiler.

SquareBUIle Electric Cooperalive AI-51 Bmn, & McDonnellNOx BACT Aualysis Smdy

Technical Literalure References: APPENDIX Al Technical FeaSIbility Assessmenl Detail, for NOx Control Technologies

I "B&W's Advances on Cyclones NOx Control Via Fuel and Air Staging Technologies", by F.rllm, 

### H., Mmingo, G., Johnson, D. W., and Wung, D.K. (Babcock & Wilcox, Co.), Beard, C.T. (EastTruln Kodak Company), nnd**Brcw't~T,** S.E.**(T~"IIllcssce** Valky Authority), presented at lhe EPRI-DOEEPA Combined UtiliLy AirPollu",n! Conlrol Symposi"m, Allnn1a, GA, August 16-20, 

### 1999. Available at B&W's intemet websile:**http://~~b~!?.cock£Q.mLp-E-r1ttlpdJ1BR**J683.ndf
2 'The State o[,hc Art

### in Cyclonc BoilerNOxRcu\1Clion", by O'Connor, Dave, Himes, Rick, ;md 1'3cchi3no, Tony (Electric Power Re.,earch Institute), pre.,ented at 

### the EPIll-DOE-EPA Combined**U~lity** AirPollut.nt Control Symposium, Atlanta, GA, August 16-20, 1999.
3 EPA Docket**OAR-2002--0076-0~46** Techmcal Support Document for BARTNOx Limits for Elecrrie Gencra'ing Unils Excel SprcadsheeI6/1512005, pow:d On lhcirwebsite: from EDOCKET at**http://docket.epa.gov/edkpub!dolEDKl'ltaffItemDetaiIView?objectld=090007d~** 8084562b; this is m;:;oeiatcd with HPA Aei(l Rain ProgrJm Clcun Air]V!arkcLs Division, Technical Support DocumentMethodologyFor Developing BART NO, Presumptive Limits, June 15,2005, OAR-2002--0076_0445.
4 MobotecUSA experience list andtedmology explanations, av.ilable from their website at htip; If**www.m.)bole~u>a..~omiprojcel:;liLlslalbtion** •.

### 1l1m ;md hltp:/Iwww.mobote...-.-.a.com/technology/rofa.htLn 5 "NOx Reduction From A**~4_]I,.fW** Wall_FiredBoiler**U~]jzing** Oxygen Enhanced Comhustion", PIaxair, by Bool, L!wrence 

### E.lli, JIld Bradley, hurou, presented at Thcl'vlEGA Symposium, Washington 

### D.C, May 20, 2003. 

### 6 "Combuslion Tempering in ConjuncllOn Wiih SNCRRcJuecs NOx Emissions Nearly 

### 60% on a Natnral Gas Fired Cyclone Boiler", posted at ,heir internetwebsite: http://ww,,,.rimcoro.comfD<Jl7Mld3ICAC.pdf
7 "Clean Coal Tcchnology: Reburn Technologies forthe Control ofNilrogen Oxides Emissions From Coal-Fired Boilers, Topical Report Number 14, May 1999"', 

### U.s. Department ofEnergy (DOE). Posted at thc intcrnet website: hll]):J f",",,'W. fo.,,'iI.energy.gov/pro

### gmmsJpO\',icrwskmslvubIicaIi0LlsiClean Coa1 TODi Ca1 RqJOr);;/topi';;1J,14.ndfg "Clean Coal Technology Programs: l'roject Fact Sheets 2003, Includes Clean Co.l Technology Dcmonstnllion Progrum, as ofM.y 2003, Octob<.-"I 2003", U.S_ DepaTirnenl**ofEn~Tgy** (DOE). Available to the public from llie National Energy Technology Laboratory's 

### Clean Coal Technology Compendium: htto;!/www.l.nLeov!projects!cele/index.html.
9 "RebumingProjccls in Ihe Dep;rrtment ofEnergy's Clean Coal Teohnology Demonstration Program", by Munn, Al and Ruppel, Tom**(parsoD~** Corporation), aud Sarku:>, Tom (N.tioJlllI Energy Technical Laboratpry), presented at the 2U04 DOE-NETL Conference on Rebuming forNOx Control, Morgantown, WV, May 18, 2004. A reburn-related document (an updated version ofa poster from the May 18 Conference) is titled "Scorecard on Rebuming 6I112004"by Al Mann andTomRuppel, Farnom Corporation, available on-line at: ll!!l1:!!www.netl.doe.govLoublicationslproceeding:;104lNOx/nostersffiebuming%20Scorecar.d.pdf .";

Burn, & McDonnell AI_52 Squa", Bulle Electric Coopenlu,""APPENDlXAI TechnicalFeasibilily AssessmentDet>ils fur NOx Control Technologies NOx BACfAnalysis Study



## •• I'J. 10 "Experience wilh Rebum for NOx Emissions Control", Engelhardt, Don, Payne, Roy, Moyeda, David, Folsom, Blair, GE Encrgy, presented allhe 2004 DOE-NETL Conference onRebuming for NOx Control, MOTglInlown, 

### VIV, May 

### 18, 2004.
11 '"B&W's Rebuming &perience", byFarzan, 

### H., Maringo, 

### G., Yagiela, A., Kokkinos, A. (Babcock& Wilcox, Co,), presenled al Ihe 2004 DOE-NETL Conference on Rebuming for NOx Control, Morganlown., WV, May 18, 2004. 12 "B&WCyclone Rebum Leads 10 No,. Reduclion, Wisconsin Powcr & Light Co.. Nelson Dewey Unit No. 

### T' (case history from B&W's inlernel websile http://www.babcook.comlpgglpslcasehislories.html.dated 1997).
B ''Rebum TechnologyApplication Guidelines", Moyeda, David, Hartsock, Don, and Payne, Roy, GE Energy, presented allhe 2004 DOE-NETL Conference onReburning for NOx Control, Morganlown, WV,May 1&,2004. 14 GE-EER experience lisl, Scplember29, 2005. ForwaJl-fued coalreburn, and gas rebum with SNCR, see "Powerplant mosaics: pavingthe way 10 O.l1lbIMMBlu without SCR", byFolsom, Blair GE Energy, published 

### in the March 2004 issue ofModem Power Systems. 15 "Predictions ofFLGRat Commonwealth Edison's Joliel Unit 

### 6" by NGB Technologies, posled on their website: http://'mVW.ngbtech.com/subpageslurojfjo]jet results html 16 ''FLGRAdvisor '"": ABollerEvaJuation Tool forFLGR-Based NOxReduction Syslems byNGB Technologies Inc., posted on their websHe: http://www.ngbtech.eomlsubpageslprojll1gr advisor.pdf.

"h 17 "CFD Evaluation ofFuel Lean Gas Rebum (FLGRThl) and Selective Non_Catalytic Reduction in OwensboroMunieipai Utilities' Elmer SmithStnlion", by Wang, David H., Cremer, 

### Mare 

### A., Adams, Bradley

### R. (Reaction Engineering International); Frizzell, 

## Kn. (Owensboro Municipal Utilities); Dusatko, 

## G.c. (Sargent & Lundy), presented at the 2001 US EPA!DOE MEGA Symposiumon SCR and SNCRs, Chicago,lL, August20-23, 200L
18 FuelTech experienoe list dated 112812005.
19 SNCR "While Paper", Inslitute ofClean Air Companies, Ino. (ICAC), SNCR Committee, May 2000, Fuel Tech websitehttp://www.fueltechnv.comlpdIiTPP-534.pdf. 20 

### RJM: experience list, September 3, 2004. 21 ''NOxStar'" PlanlDemonslration, Octoher2Q{)J", byMorris, K.W. and Hesselman, G., Mitsui Babcock (US), presented at the 200J U.S. 

### DQE Conference on SCR and SNCR forNOllControl, Pittsburgh, PA, October 29-30, 2003. 22 "InSlllllation ofNOxStarTM System at TVA Colbert", by Morris, KeithW., Milsui Babcock (US), pre&ented at tbe Coal-Gen 2004 Conference, July 28-30, 2004, Overland Park, KS. 23 "Improved Rich Reagent Injection (RRJ) Perfonnance ForNOx Conlrolltl Coal FiredUlililyBoilers" by Cremer, Mare A. and Wang, HuafengD. (Reaction Engineering International), Boll, David E. (AmerenUE), Schindler, Edmund 

### (RIM Corporation), andVasquez, Edmundo 

### RMT, Ino, (A11iant

Square**Du~e** Electric Cooperative AI_53 Burns & MoDOIlIleilNOx BACT Analy'is Study APPUNDlXAl Toohnioal FoasibililyA,'t""1Ilenl Details fOT NOx ControlTechnologios
Energy Corp.), pre.,enled al2003 U.S. DOE Conferencc on SCR ami SNCR for NOx Control, Pitlsburgh, PA, October 19_30,2003. 24 "Design and Demom;tralion ofRich Reagent Injections (RRI) Pcrforrrumec For NOx Reduclion at ConnecIiv's BL England Sl<llion" by Cremer, Marc 

### A. und Adums, Brucllcy

### R. (Reaclion Engineering**Intema~onal);** O'Connor, DJvid C. (Electric Power Research "lnslilule); Bhamidiputi, Venka i<l (Conccliv 

### BL England SInlion), 

# ,me Brodcliek, R. Oiffol"d (RJM C'-Orpomlion), presenled at the 2001 US EPAJDOE/EPRI MEGA Symposium On SCR**~nd** SNCRs, Chicago, IL, AugUSl 20-23, 2001. (available from REI's in[ernel web.ile**http://\''iww.reaclion-cn~.eornldOl:!.);~loadslrri**me.a.pdjJ 25 "Delllon,tr.:ltion ofRich Reugenl blJection for NOx Conlrol in AmerenUE'. Sioux Unit 

### 1"by Cremer, Marc A. andAdam" BrndJcy R. (Reaclion Engineering IntemallonaI), Boll, David E. (AmerenUE), and O'Connor, David C (EJeelrie Power Research Institnle), pre,ented M lhe US DOE Conference on SCRI.sNCR for NOx Conlrol, Pittshurgh, PA, Muy 15-16,2002. 26 "Evaluation ofCos! Erfeclive Non-SCR Options fOl"NOx Conlrol in PRB Fired Cyclone Boilers" by Cremer, Marc 

### A., Wong, David 

### l-L and Adam!, Brodley 

### It. (Reaction EngineeringImcrnat;onal); Boll, David E. and Stuclaneyer, KCIlIle1h B. (Ame,enUE), presenled at the Western Fnels Symposium, 19ib Internalional Confercnee OnLignite, BroWll, and Subhirumino\ls Coals (formcrly Low-Rank Fnels), Oclober 12"14, 2004, Bil1ing." ML
27 "NOx Emi.<sions Bolow 0.15 lb/Mbtn Achieved in a Cyclone-Fired Boiler Usmg Tn_Furnoce Control", by Cremer, M., Adams, 

### E., und Chiodo, A., (Reaction ELlgineering International); Giesmann, 

## c.,**StnekmeY~T,** 

### K., and Boyle, 

### J. (Am="llUE), presenled at the Powergcn Inlemalionul 2005 conference, December 

### 6-8, 2005, Las Vegas, Nevada.
28 "Ash and Mercury Behavior in SCR CatJlysl' When Firing Subbituminous and Lignile COJls", Energy & Environmental Research Center (EERC) ofLhe Universily ofNorth 

### Dak(}la", Benson, Steven A., Laumb, Jason D., Crocker, (]larlehe 

### R,**~nd** Pavlish, John H. snbmitted for publicalion by Fuel Proccs;ing Te<:hllology magazinc, 2004. An edited version o[this pJper wa, pnblishcd as: "SCR Cafa[ysl Performance in FIne Gases Dcri\'ed froln Subbituminou. 2nd Lignite CoalS" by fud Processing Teclmulogy, Volume 86, Issue 5, 25 February2005, Pages 577-6]] Sleven A. Benson, Jason D. Lonmh, CharleueR. Crockerand 10hn H. Pavlish. 29 "In-Situ 

### Mini SCR Reactor" stndy, available (forpurchase from) Elecrrle PowerResearch Institnle lllC.'S (EPR!'s) imernet websile at hllp:!/WWW.wri.comln_ewslette•.asp?issucid=297305&ma.ketL.id-270619&1iITgefnid--=270677&\'.alne= OST073.0 30 "Recent Experience With Hilachi Plale Type SCR Catalysl", Morita, lsato, Ogasahara, Toru Franklin, llowardN., Babcoek"Hiluchi HK. and Hitachi Amerieu lechnical paper,**pres~"Dled** 10 The In,lilu!e ofCIcun AirCompanie", Forum '02,February 12-13, 2002, Washington,D.C. 3\ "Perfonnance OfSe1eelivc Call1lylic Reduction On Coal·Fired Steam Generaling UnilS"U.S. EPA Oroce ofAir and Radiation Aeid Raill Program Fin"l Report, (6204-J), Jnne 25, 1997.
J2 "Rolaling Opposed Fire 

### Air (ROFA) and SNCR·" by Shilling, Mark ond Tonamaker, Gary (Carolina Powel" & Light Co.),**pr~smlCd** at the 2002 DOE-NETL Conferellce on Unhurned Carbon On Utility Flyash, May 14, 2002" I'itfsbnrgh, PA.

Burns & McDunn.a Al-54 SquareBulle**Ele~rric** Cooporative

### APPENDIXAJ TochnicalFeasibilityAssessmenlDetails rOT

### NOx ConlrolTechnologies NO" BACT**A.oal~si,** 

### Sludy

33 "Injection ofUrea lhrough the Rotamix Systemto Obtain bnprovcd NOx**Reduction~,** 

### by Ralston, John and Haddad, Edwin (11obotee USA, Inc.), presented allhe 2003 UK DOE Conference on SeR and SNCR for NO" Control, Pittsburgh, PA, October29-30, 2003. 34 "SCR Levels ofNOxRedudion wilh ROFA and Rotamix (SNCR) at Dynegy's Vermillion Power**Sta~on"_** 

### by Coombs, Kristopher A. Sr. (DynegyMidwest Generalion), and Crilley, Jay S., Shilling, Mark and Haddad, Edwin (Mobolec USA, Inc.), presented at the 2004 SlackEmissions Symposium, C]earwa"r Beach, FL, July 28--30,2004. 35 "First Commercial Installation ofAmIne Enhanced Fuel Lean Gas Rebum OnUnils I and2 atPublic Service Electric & 

### Gas Mercer Station", by Gomez, Andrew F. (Public Service Electric & Gas 

### Company (PSE&G) Mercer Generating Stlllion), Dainoff, Alexander S. and O'Leary, John H. (Fuel Tech, Inc.), and Schrecengost, Robert (Energy Systems Associales), pr",enloo al the 2000 DOE· NElL Conference on SCR and SNCRforNOx Conlrol, Pittsburgh, PA,:May 17-18, 2000.

Sqwrrc Butt<: EJoctric Cooperative 

### AI_55 BtIJI\S & McDOIIIIeHAPPENDIXA2 u.s. NOx Control RetrofilProjects


### A.2.1 • U.S. Cyclone NOx Reduction Projects Summary NOx BACTAlllllysis Srudy

1962 vintage eaSlOrnbiluminous coal



# -.- SELECTIVENON-CATALYTiCREDUCTIONI RICHREAGENTINJECHON CYclone-Fired 

### Boilers Conectiv (formerly Al1antic Electric) BLEngland Unil I Crushed Coal. single-wall cyclone-fired 138 MW B&W boiler aqueous 

### urea SNCR, 1995 startup Boilerhas only 

### 3 cyclone burners, arranged "lover 2" style. 

### RJM: implemented commercial FuelTech urea-based SNCR system installation in 1995 after short-lerm (3-month demonstralion test) in 1993-1994_ 31 % NOx reduction claimed, from 1.311b1mmBluNOx baseJine(') for SNCR only; 

### RJM: claimed 35%:reduclion from 1.311blmmBlu down 10 0.851blmmBtu (withoul overfuc air) with urea_lo_NOx NSR = 0_85 (RJNr experience list). Added eight lemporary 

### RRI porls (three nozzles on each lower sidewall, and lwonozzles on the upper rear wall, andperformed onemonth demonstrationpMameLric lcslIng ofoverfire air only (without SNCR or

### RRI), at 120 

### MW nominal boilerload and cyclone S.H... = 0.90 

### in 1999. 

### REI claimed 55% NOx reduction from a 1.21bfmmBm uncontrolled NOxbaseline to 0_551b1mrnBlu with OFA only, with sloek CO emissions below 50 ppm_ For Rich Reagenl Injection; 

### REI claimed 25-30% NOx reduction forRRI down to 0.38lblmrnBtu fromconlrolled baseline wI OFA aloneof0.55 IbJrrunBtu NOx and a IUU oreat<>-NOx NSR = 2; also showed RRl+SNCR wi OFA reduced NOx 55% [0 0.251b1mmBtu (34% beyond RRI wi OFA), for an ovcrall79% NOx reduction with a SNCRurea-to-NOx NSR = 1. Measured less than 

### I ppm ammonia slip during 

### Rill lesling, 

### < 5 ppm slip for 

### Rill + SNCR. No significant inorease in CO emissions during 

### RRI lCslin!?'). Source: ('JlCAC \¥hile Paper; 

### RJM: experience list; (2)REI 2001 Technical Pap<::r. Conecliv (formerly Atlantio Electric) BL England Unit 2 Crushccl Coal, eyclone-lrrcd, single-wall-fired 1964 vinlage 160 MW B&Wboiler SNCR, 1996 startupeaslern bituminous coal 

### RIM implemenled commerc:iul Fuel Tech oren-based SNCR syslem in 

### 1996, claimed 36% reduction from 1.361b1inmBlu down to 0.85 IbJrnniBtu, urea-to-NOx NSR= 0.85 (wilhout overfirc air)(l)_ An OFA system was acldcd in 1998, resulting 

### in NOx emissions of0.33 IblnunBtu, for an overall NOx rccluclion of76%. Source: RJM experience lis\. (Also lisled in ('JlCAC WhitePaper). AmerenUE (formerly Union Eleclrie 

### Co_) Sioux Unil 

### I CrushedCoal, opposed_wall cyclone-fud 1969 vinlage S(){I MW B&Wboiler Rich R""genlInjection demonstration testing in 2001 Boiler h,s 10 cyclone burners, arranged "2 over 3" style, on opposite walls, and fires a blend of85% to 50% western subbituminous 

### (PRE) coal, with Illinois bituminous coal, petroleum coke, and lire-dcrived fuel. installed twenty temporary 

### RRI ports (sixnozzles on each lower sidewall, and four no=les on each 

### fronl and reaT wall), and performed one monlh demonslr':ltion parnmetrie testing ofoverfire air only and inilial teslingwith 

### RRl in August2001, followed by additionallCSling inMareh 2002, and Ibe second qnarter of 2004. Added 8 

### RRIports 

### (I in each sidewall, 4 in each front andrear wall) and 14 SNCRpons (5 on upper front wall, 

### 9 on upper TeaTwall) to lhe furnace in early2005, followed by lhree weeks ofparametric tesling and 3 dnys ofcontinuous testing ofRRl wilh SNCR and deeper-staged OFA. Tested in Augusl2001 at lower furnace SR approx_=LO, 0.551bJrnmBlu 

### wIOFA only, only 15% NOx reduction wi 

### RRI, zero smmonia slip.
SquareBune E1e<:lric**Cooper.l.~ve** Bums & MoDonnellNOx DI\CT Afialys;s STUdy APPENDIX 1\2 U.S. NOx COfilrol Relrofil Pmjeol'

Tcslcd inMareh 2002 at lower**f"mu~o** SR**upprox.~.95,** from 0_J81h/mmBtu baseline wi OrA only, achieved 29% NOx reduclion 

### wi RRI <1o\'>'Il [0 0.27lhlrrnnBtu, NSR=J, zero mmnonia slip(3). (assume blend o£PRB and Illinois bituminous coal w/lire-dcrivcd fuel nnd pelro!eum coh)PJ. Operation in the .,econd qum-ln2004 showed actual stuck NOx '''''roged around 01'0.30 Ib/mmEtu with O:rA ooly and lower furnace aL u cyclone SR around 0.88 hurning a 85% PRB, 15% minois #6 bituminous coal blend, presumably at 440 MW. Tbjg is a 75% NOx reduction from a 1_19 IblmmBtu pre_ conlrol b"sclinc. REI using CFD modellOgpredietc<l NO;,: <lown to 0.18 lblmmBlu wilh lUU+Ol'A, "nd below 0.15 WiIh RR1+SNCR under similar deep cyclone air-SIaging (1.19 to 0_28 lbfmmBtu is 76% reduction, 0.18 v., 0.28 i.' an addiiional3G% reduction 

### wi RIU, and 0.14 vs 0.28 is a 50% reduction 

### wi RRI+SNCR, 

### for un ovemH reduclion 01"88%)1').**Te.'t~d** in May 2005 at 480 MWgwilh lower furnace SR approx. 0_85_0.88, 76-83% reduotion froln 1.2 Ib/mmBtu baseline down to 

### a' low as 0.20 lb/rrnnBlu wi SOFA only firing 80% PRll, 20% U1inois 

### 116 bimminous coal blend; addiliorulI15-J9% NOx reducjion w/RRI, to as low ns 0.15lb/mrnBtu from 0.20- 0.28 lblmmBtu baseline 

### wi SOFA only al urea NSR varied between 1 and 4, wilh ooe ppm ammonia slip;**~chicvcd** additional NOx reduction 

### wi RRI +SNCR down lO O.121b1mmBlu, NSR=I, anunonia slip10 ppm or less. RR1+SNCR 

### wi SOfANO" reduction percentage vaned from 15% to 50% below SOFAonly kvcls, with NSRs between 1 and 4.5. SNCR alone had 13%**(NSR~l)** to 32% (NSR=1) NOx reduclion willi ammonia slip around 1-2 ppm*-. Source: (3) REI 2002 and 2003 Technical Papers; (')REI 2004 Tedmicul paper;*- REI2005 Technical paper. 

### REBURN

- GAS, CONVENTIONAL Cyclolle.-Fired Boilers ConslclMion Energy (formerly Baltimore Go, & Electric) C.P_ Crane Slation, Units 1 & 2 (MD) Crushed Coal. cyclone-lJred, eaSIem bituminous coal 2 X 200 MW B&W boilers ([our cydoncs ""ch) 1%1, 1963 vintage GE-EER Convenlional G"-S Reburn, 1999 startup Ad<led gas ,upply piping, metering, haogers, supporlo;**r~blJlll injc~lor"**  and cooling air ductwork, OFA duclwork, injection noz:lles and wnllports, field (assume ea,tern bituminous cool) GE-EER olaimed Gas Rehurn willi OFA 10w=<1 NOx bcLween (,(J% and 65% from ba>elines of1.50 Ib/rrunBlu to**b~lwcen** 0.60 and 0.52 lb/mmBtu, at full load withrcbum operation. No claims ofperccnt rebum fuel orpercent OFA included in GE-EER

### 's experience 

### li,t Another lechnical paper sho"lcd this inslallation ofCGR operatedwiLh 25 p,,"ccnlrcbum [lid'). Source: Sept. 2005 GE-EER experience list; (S)DOE_NETL Scorecard on Reburning 

### 6/1/2004 (from 2004 Rebum ClIlucrcncc). City Wntcr, Light & Power Lakeside Unil 7 Crushed Coal, front-wall cyclone-fired, midwestern bituminous coal 300,000 Ib/hr steam B&W boiler (approx. 33 

### MWG equivalent, two cyclones) 1961 vinlage Springfield, 

### II. DOE Clean Coal demonstralion projcct (includcd sorbent injection) GE-EER conventional gas rehum 

### wi OFA 1992 startup (CGR not currently operating) Vendor c1aimcd to 10"lcr NOxby 66% from 0_95 lb/mmRjubaseline to 032lbfmmBlu. A GE-EER 2004 technical paper ,howed 25% rebum fuel yieldcd minimum NOx emissioo"l.). A DOE NEIL lechnical paper showed Ihis demonstration ofCGR from 5/93-10/94 (assume with OFA) with 23 percenlrebum fuel**rcdu~ed** NOx 60% from 0.97 10 0_39IbfmmBLuls). Source: Sept. 2005 GE-EER experience lisl; (6]GE_EER 2004 Technical paper; (5)DOE_NETL 2004 Rcbum Conference Technical p"per. E"slmanKodukCompany Kodak Park Boilers 41 & 42 Crushed Coal, [runt-wall oyclone,fired, 1964 & 1966 vinl"ge

BOTII'l & McDUllJlcll A2-2 Square Butle Eleotric Coopcm(iveAPPENDIX 

### A2 U.S_**NO~** 

### Control Reuofil Projects NOxBACfAnalysis Srudy**~OO,OOO** 

### Iblhr steam B&W bQilers (approx. 50 MWe equivalenl, tWO 

### 8-ft dia_ cyclones) Rochester, NY eastern bituminous coal B&W convenlionul gas reburnwi OFA December 1998, July 1998 slartups (still operating) Corrnnercial installation ofCOR, with (I) gas burner added 10 each sidewall 

### + (2) large and (2) small OFA ports added to front wall above cyclones, utilizing higher rebum 

### gas pressure (vs_ Boiler#43) requires uo flue gus recirculatiou; (Very smull furnace 

### wi cyclone SRnot <1.0J. B&W claimed rebum with OVA 

### loweredNOxby 50% from L20 IblrnrnBtu baseline to 0_6IblmrnBlu. B&W graph shows 10-12% percentrebum fuel to 

### achieve 0.61b1mmBtu and 23-24% reburn gas input to reach O.33lb1rnmBtu NOll. (73% reduetion)(7). Anolher lechnical papershowed**NO~** 

### lowered by 52% from 1.25 lbIrnmBtubaseline 10 0.60 IblmmBlu with 18 penoentreburn fuel(i). Source' ( 1J

### B&W Tedmical Paper; (;lODE_NETI.. Scorecard on Rebuming 61112004 (from 2004 Reburn Conference). 

### REBURN- GAS, CONVENTIONAL CYclone-Fired Boilers, continued EastmanKodak Company KodakParkBoiler 43 Crushed Coal, front-wall cycloue-fired 1968 vintagc 600,000 Iblhrslcam B&Wboilcr (approx. 60:MWe equivalent., two cyclones) Rochester, NY eastern bituminous coal B&W couvent.ional gas 

### rebum 1995 stllrtup (still operating) Commercial installation ofCOR., with fiue gas reciroulation (FOR) for injection mass momentum wI (1) 

### FOR fan; (1) gas burneradded to eaoh sidewall 

### + (2) OFA ports added frout wall abovc cyclones. {Very small fumacellow reaidence time 

### wi oyclone SR not<l.O} B&W claimed rcbum wilh OFA & FOR loweredNOx by 50% from 1.20 IblmmBlu baseline 10 0.6 lb!mrnBtu_ B&W graph shows 18% pcrcontrebumIucl 10 achicve 0.6 IblmrnBtu and 29% reburn gas**inp~llo** 

### reach 0-36Ib/mmi3tuNOx (70% reduclion)t7) 

### Anollier teclmioal papershowed NOx lowered by 56% from 1.351bhrrmBtubaseline 10 0.60 IblmrnBlu with 18 percentreburn [uellS). So,u.;,e, [7j 

### B&W TeohnicalPaper; (5) OOE·NETI.. Scorecard on Rebuming 61112004 (from 2004 Reburn Conferenoe). Tennessee Valley AUlhority (TVA) Allen Station Unit 1

## erN) Crushed Coal, cyclone-fired (seven cyclones) 1959 vintuge 300 MW B&Wboilor PRB &westembituminous coal blend fired OE-EER Conventional Gas Reburn, 1998 slartup Corrnnercial inSlalialion added gas supply piping. metering. hangers, supports; reburn injectors and cooling airpiping, OFA dnctwork, injection nornea and wall ports, field I&C devices. Reburn with OFA claimed to lowerNOx 65% frombaseline 1.20 Ib/mmBtu 10 0.421b1mmBtu) at full load wilh rebum operation_ No clailll5 ofpercenl rebum fuel included. (IV

### A also inslalled duplicate OFA syslems on Allen Uuits 2 & 3 boilers). • Another technical p"pershowedNOx lowered by 65% from 0.861b1rnmBtu baseline (to 0.30 IblrnrnBtu) willi 7 percent rebum fud(5). Source: Scpl 2005 GE-EER experienoe list; (5)OOE_NETI. Score<:ard on Rebuming 6/1/2004 (from 2004 Reburn Conference).**REBURN~** 

### COAL, CONVENTIONAL Cyclone-Fired Boilers 

### Alliant Energy (fonner1y Wisoonsin Power & Light) NelsonDewey StationUnil2 Crushed Coal, cyclone-fired, PRB coal Square**Bu~e** 

### Eleotric Cooperalive 1962 vinlage

Durns & McDonnellNOxDACT An.lysis Study il.PPENDIX A2 U.S. NOx Contrul RctroJil ProjeCIS

110 MW 8&'1'.' bajjer ].cyclones across front wall, 4rebuffi hurners 

### + 4 0[1A paris across rear wall, aligned verticany in co]urrm,. US DOE Clean Coal DemonslrJlion projcct ofB&W's Conventional Coal Reburn, 1991 startup (since disconlinued) added coal supply piping, reb\lm burners with fluc gas**recircul~lion,** OF

### A ductwork -I- duul zone pOrls; coal feeder, pulverizer & PA 

### fm, lcslcd withPRB 

### nml biluminolls coals. (western slIbbi!uminolls coal) B&W tluimcd rebllm opCTulion lowered NOx by 57% from baseline of0.83 mm81llto 0.J81blmmBtll at flln 10ad(1). Approx_ 30% peroent oftolal fuel inpul oupplicd u, rcbum fuel. Inorcuscd Mil outpul by 10 MW, increased f1yash IlIlhurned**c~rbnn** by 4% (13·22% vs 9-18%), dccreased furnace exit gas lempe,alure (FEGT), OFAports lisled in B&W experience list. B&W shows full load NOx "I/o reb\lm was 0.75 Ib/mmBtu, und 0.29-0.321bfrmnBlu wfPRB fuel during reburn operation (57% decrease). At 75%**10~d,** 0.64 vs 0.29·0.321b/rnrnBru. At 55% lood, 0,62 vs 0.29_ 0.311b/mmBlu wilhout and with rcbum Jc1ivated(1). Anoilier lechnical paper showed NOx loweredby 52-55% from 0,821bJrnmBlll baseline (10**0.~9-0.34** lb/rnmBlu) "'ilh 25-30 pe'Iccnlrebulll fud5 ). Source: (7]2004 B&W Technical Paper; 1 5)OOE·NETL 2004 Rebum Confcrcnee Tcchnical poper; (')B&W casc hlOtory (from wcbsite, ,bled 1997).


### REBURN

- COAL, MICRONIZED, CONVENTIONAL Cyclone-Fired Boil

..s £"slmJn Kodak**Comp~ny** Kodak Park :I15 BOller Crushcd**Co~l,** front-wall cyclone-fired, 1956 vinlage 400,000 lbJhr ste.m B&W boiler (approx_ 50 MWe equivale"" two cyclon",) Roehcslcr, NY caslcm bituminous coal GE-EERmicronized coal rebum 1996 inilial Sla.rtllp (operolling since 1997) DemOOSlI1llion projcc1 performcd 

### with Dept. ofEnergy's US Clean Coal Technology Progralll- Project added nue gas rec,cculatlOn for injection mass momentum, FGR [on and lWo micronized coal pulverIzers; (6) rcburn coal injcclors addcd lo roar wall 

### + (I) rebmn coal injector on each ofthe ,idewalls, wilh (4) OFA ports added across rrontwaH above cycloncs(OJ. GE-EERdesigned Jnd fabricoted lhe coal injeclors amI OFAporls. [E}(tremcly sm.ll furnace and low residence lime]_ GE-EER claimed rebum 

### + OFA wi FGRreduced NOxby 50% from 1.20 lb/mmBtu baselineio 0.6 lb/mmBtu. No cl.ims ofpercent reburn fuel included_ Another lechnical papershowed lhi.'; demonsIralion ofmicronized cool reburn from4N7-l0/98 10wCTC<l NOx by 57% from 1.361bhnmBlu baseline (to 0.59 lhlmmBtn) with 17 percentrcburn fucl(5). Source: (l')DOE TopIcal ReporlNumber 14 (May 1999); GE-EER experience list;(;)DOE-NETL 2004 Rebllm Conference Technical paper. 

### REBURN

- FUEL LEANGAS REBORN Cyclone-Fircd Boilers Midwesl Geoemtion (formerly Commonwcahh Edisnn) Joliet Station 9, Unil 6 Crushed Coal, opposed-wall cyclone·fired (nine cyclones) 340:M:W B&W boiler 1959 vinlagc, 1997 ,IJrtup (FLGR has since been decommis..,ioned) Energy Syslem, N;soci.les dernomtr.ted 25-30% NO;;; reducllon using 5-10% ofto!al beal inpnt as reburn naturJl g;lS injcclc<l (wilhou! OF 

### Al5). Another teclmical paper showed this demonslralion in colbborolion witb Gas Researcb Institule ofFLGR lowered NO>:. by 28·43% from U61bJrnmBtu baseline (to O.59lbJrnmBlo) wilh 7 percent rcbum fud'Ol. Source: ('JDOE-NhlL Scorecard on Rebuming 

### 61112004 (from 2004 Rebum Conference); (10) NGB Tcclmologies Technical Pupcr. "'.

Bum' & Md)onncll Sq= Bune Elct:lrio Cooper.liveAPPENDIXA2 u.s.**NO~** ConiiolRetrofitProjeclS NO>: BACT Analysis Study



### 1965 vintage CrushedCoal, front-wall cyclone-fired (lhree cyclones) 

### REBURN-FUELLEANGASREBURNwlSNCR continued Cyclone-Fired Boilers 

### Owensboro Municipal Utilities (KY) 

### Elmer Smilh Unit 1 150 MW B&W boiler CFD model study only predicted NOx reduclions from 

### 1.59 to 0.39lbfmmBtu with OFA only (75% reduction, 0.90 SR); 25-30% NOx reduclion using 6% oftolal heat input as rebum natural gas injected above OFA; 40-45% NO" reduclion from SNCIl with 

### <5 ppm 

### ammonia slip(Il). Source; (11) REI Technical paper. Separated 

### OVERFlREAIR Cyclone-Fired Boilers 

### TennessecValley Authority (TVA) Crushed Coal, <:ydone-fJrcd, 1959 vintage Allen StHtion Unils 2 & 3 (TN) (seven cyclones) 300 MW B&W boilers PRB &we,;lern bituminous coal blend GE_EEROverfJrc air (duplicale ofAllen I), 1999 slartup GE-EERciaimed 10 lowerNO" with OFAalonc lip to 

### 29% from baseline 1.20 IbfmrnBtll to 

### 0.85 IblrmnBtu onUnits #2 and 3 at full load. Source: Sept. 2005 GE-EER experience lis!.



### , , 

### AmerenUE (formerly Union Electric Co.) Sioux Unit 1 Crushed Coal, opposed-wall cyclone_fired 1969 vinlage 500 MWB&W boiler PRBflllinois Coal blend Bol1erhas 10 <:yclone burners, arranged ''2 

### over 

## r style, onoppooite walls, and fires a blend 0[g5% 10 50% western subbituminou5 (pRB) coal, wilh Illinois bituminous coal, petroleum coke, and lire-derived fuel. A lco-port OFA system (five ports on each front and rear wall) began opcr.ltion inmid_2001, which reduced NO" emissions appro". 40-50% reduclion from 1.1-1.3 (assume average of 1.19) down to 

### 0.7 IbJrmnBlu wilh moderate cyclone air-staging (cyclone SR from 1.19 10 1.0). (') Subsequentte.sting and full load operation at deeper <:yc1one air-staging (SRs :s0.90) has dropped NOx with SOFA aloue 10 around 0.3lbfmmBtu in 2004<). Source: (:l) 

### REI 2002 and 2003 Technical Papers; «)REI 2004 TeChnical paper;* REI 2005 Technical paper Coal burning cyclone-firedutility boilers in the Uuited Stales thaihave been retrofJtted with 

### Separaled Overfire Air CR technology are listed in Table A.2_I, A large majority of111e cycloue-flred boilers listed burn western subbitumiuollS coal (orPRE blended withmidwestern bitumiuous coal).

Square**Bu~e** 

### EleetricCooperative BllIIIS & McDonnell**l\'O~** BACfAualysis**S~cly** APPENDlXA2 U,S, NOx Control Retrofit Projects


### TABLE A.2-1
- Cyclone-Fired Boiler Overfire Air Retrofit Installations(") Facility Name Installalion Dale Comment.

SCRrelrofit 511112004 SCRretroI1t5/0 112003

Similar to Joliet 9 Unil6 SNCR demo May 2005 SCRrctroli( 5/011200I SCR reLIofi15!01l2000 SCRrelroill 311012004 SCRTclrufil 1211712002 SCRTctrofil6/0712002 OFA

### wi CGRretrol1l: has SCR (Similarto Unit I. wlo CGR) h,ve SCR (SinlilaTto Unit I, wlo CGR) h,ve SCR Empire**Di,trie~** BART-eligIble SCR 10be ,"smned in 2006-7 SCRretrofit 5/1112004 SCRretrofit412312003 SCRrerron, 4/12/2002 part ofconversiolllo PRE previous SNCR,elrolil in 1996 OFA wi COR relrolit SCR retrofil 412112003 SCR lelront 410912002 Alkn Station Unils I Iasialled 199R· Allea SmtionUn;l 2 Imlalkcl 1999± AlleaSlation Unit 3 Inslalled 1999* Asbury Uoil I In,[,lled 5/10/1999 BaUly Unil 7 Insl,lled 2003(IJ) BaillyUnll 8 [ru;l,lled 5!J112000 Baldwin Unil 1 .lru;lalled 12/31/1999 Baldwin Unil 2 Inslalled 5/&/2000 Big Slm,o UniI I**l.JlSlall~...J** 10/22/1997 BL England Unil2 InslaUed**1998~** CP Crane Unit 2 luslalhl2/111999 Colleen Unill Insmlled2f1l2001 Coffeen Unit2 Inslalled21912000 Edgowatcr Unit 3 Iuslalled 1112001''') Edgewater Uni,4 Installed 61 j 9/2001 JoJiel9 Unil6 Installed 2000°>1 Kiaoaid Unil 1 Imirllled412812000 Kiacaid Unil 2 Jnstallod5/24/2000 Allea S. King Unll1 Jmlalled 1Jl30/1999 LaCygne Unit I Jmtalled 212812000 Lake Road Unil6 Imlal1ed 6/0112002 Michigon City Unit 12 Imlalkd 4/1998(ll) NelsonDeweyUnit I lmlaJlcd 2002(llj Nelson DeweyUuir2 Imlallcd 2002(ll) Pal.diseUnit I Imlal1ed 11/14/1993 PaladiseUui, 2 1rrslancd 1218/1999 P310diseUuitJ lnslallcJ 5/412000 PowenonUnit 5-1 lru.lallccl 61112003 PowertonUllit 5-2 lnstalJe<.l6/112003 PowertonUnit 6-1 In'tlIUed 61112002 PowertnnUnit 6_2 Inslalled 51411999 Schahfcr Unil14 InsmJIed early 2000(1J) Siblcy Unil2 blSlalled 512412()()2 Siblcy Unit3 Inslalled 5/4/1999 SiollXUnit I Inslolled 4/301200I Sioux Uuil2 Inslolled 4130/1997 Slale Line Unil4 Installed 1112001 (lJ) Tannen: CrcdL Unil4 Installed 5/1212002 'l11oma, Hill Unil 1 bl5lalled Jnne 2004(1)) 

## .lllOma, HiJJ Unil2 lusmlled Novembc.,- 2oocf") NOle: 11tis lable does not include ovory m,irlJled U.S, coal_frred eyclone bmlcrOFAretrofit project. Sonrce: (")US EPA Docket OAR-2002·0()76·0446 Technical Support DocumentforBARTNOx Limils for Ekctric Generatiu£ Unils Excel Spreadsheel 611512005 (except OS uOled below)

Vendor eKpene""e IlSI (GE Encrgy lorAllen StationUnu, 1-3; RJI\1 rOT BL Engl.nd Unit2) (lJ) BlIttlS & McDollI1ell in!<:mal dalab,,,"_


### Coal burning cycione-fired utiliry boilers in !he United Slales thai 

### hnvc bcenretrofitted wilh SCR 

### lcchnology arc lisled 

### in Tuble

### A.1-2. This lis! ineludes utlcas! eighleen eyeJone-fircd lmilors bwning weslern subbilurninous ooal (or PRE blendedwith midweslern bituminous coal). Tho highest emission

Bums & McDonneU A2_6 SqO<lfe Bnne Elcetrio C".<lopenlliveAPPENDIXA2 

## us. NOx Control Rctrnfil Projee!s NOxBACTAnalysis Study



## .... reductions listed 

### in Table A.l-l for SCR syslems 

### arc for

### clean reactor catalystand ideal opemting conditions. 

### TABLE A.2·2 - Cyclone-Fired Boiler High-Dust SCR Installations

2003 Ozoue Se.,on Unit AverageNOx Size',M Tested Outlet NO

### x Emi"ion Rate' F.ellily' W Tested CO':$OI**Efl~SIOn** Rate (lblmmBtu) Emcien bltnnIlllu)'**Anenl.2.&3'~** 330 ea. 91.1iNAD'/88.7 0.07O!NAD'/0.088 0.088/0.071/0,086 Baldwin 1,,6 600' S2.9 0.072 0.238 Baldwin

### 2''- 605' 83.5 0.067 0.2a6

Bailly 8'" 

## m NAD' NAD' 0.84 Coffeen I'" 

## ,W NAD' NAO' 0.114 ColTeen2'" 

## on NAO' NAO' 0.120 Dallman 3t & 32**,~** NAD' NAD' 0,149/0.146 Kincaid I & 2'" 660' ea 89/89 0.079/0.079 Q t81/Ll9S Marion4 

## m 94.3 0,067 0.252 Merrimack**l'~** 

# '" 50.5' 0.148 0.158 Merrimaok 2 

# ". 513' 0.155 0.171 MiclJigan Ci<y 

## 12',,· 

# "" 84.2 0.109 0.4 I 8 New Madrid t &2"" 600 ea, 87.4/88.1 0.149/0.147 0.31911.172 P=dise I &**2~'** 704 ea, 87.7/87.7 0.10210.101 0.12410,113

Paradise

## 3'" 1150 89.1 0.088 0.658 &hahfcr 14,,'0 

# ''" S3.5 0.106 0.478

ongmal deSIgnfuel for all h,ted eyclone bOll"", waS b,lUInlUOUS coal

, - Generatornameplale rating, Marcb 2002 Energy Infonnalioo Administration :report DOElEIA-0095(2000). Actual unitMW outputrating maybe higherorlow",- lhan nameplate. '- Bun1< & McDoDJIeU internal c.labase

. • - as reported to US EPA, available from their websile alhllp:/icfpub.epa.gov/gdmlindex.dm

, - includes applieation ofscparn.lccl overlrre air for combustionNOx control
, - cuneo! fuel believed lc be a blendof,ubbiluminous and bituminous ooal. '-NAD no**p~blisbed** dola rrom SCR cmissio;' resting found 0.0 iliese unill;.
, - original airprelle.t",-, were tubular_type; changed 10**rolaI)'-~** during SCRretrofit

• - DesignNo,. removal elIiciency is higher, approx. 90%. LO

_ ourrenl fuel beJiovoo to be ,ubbitumincU-' coal
For MemmaokUnit I's 

### SCR, inlet (i.e. uncontrolled) 

### NOx was 134lblmmBtu, for a blend 

### <>f high sulfur biluminous and medjlJl1l. or low sulfurbituminous coals, arid requires year-round 

### SCR operation for compliance. The catalyst was designed 

### for 88.9% NOx removal**efficien~y**

8qUBrCButte Electric CooperatIve A2_7 BllTIlS &**M~Donnell**NO"IlACT Analysis Shldy APPb"'NDIX A2 U.S.**NO~** ConrrolRelrolilFrojocl,

and 5 ppm ammonia slip. SCR**comm~Tcial5Crvice** date July 20, 1999. [(l<) Bahcock Borsig Power2000 tecbnical paper on SCRs].
ForMerrimack Unil2's SCR, inlet (i.e. uncontrolled) NO:< was 2.66IblmmBtu, for ablend of hillh sulfurhituminous anu :rm:uium or low sulfur bituminous coals, al1d reauires ycar-rolmd SCll operalion for**comrlian~e.** Inilial lcsling demonstraled 70% removal(! ), which**ex~ceu"d** !he 65% requircmenllo aehieve a 0.92 Ib/mrnBlu permit limit The cal.lyst was designed for 85-95% NO" removal efficiency and 5 ppm ammonia slipl"} C"lNETL_DOE Clean Coal Technology 1997 kchnical paper on SCRs; (10 1997 ICAC Whilc Paper on SCRs. Northern lndiana Pobli" Service Company (NIPSCO) Bailly Unit 8 Crushed Coal, cyclone-fired, oppo.,ed-wall-fired 1968 vinlage 

### 360 MW B&Wboilcr Urea/ammonia**~onversion** for high-dust SCR, 

### 2004 startup Boiler fires a blend of85% western subbilllffiinous (PRB) coal, with ll1inOis bituminous**~oa1.** Commercial Fuel Tech urea-based syslem installed in 

### 2004 to convert urea!o ammonia for**injec~ng** reagent ahead ofboiler economizer outlet**~nd** high-dust SCR. An OFA system was retrofit1edin 

### 2000(U!. Source; Fuel Tech o:xperience lis! dated 1/28/2005;**C'-'~ums** &MeDonncll internal database. Northern lndian. Public Service Company (Nll'SCO) Michigan CiryUnil 12 Crushed Coal, cyclone"fired, opposed-wal1-fired 1974 viutage 

### 520 MW B&W boiler Urea/ammonia eonvcn;ion forhigh-dusl SCR, 2003 startup Boib fires w<;g[CTII subbnuminous (PRB) coaL Commeroial Fuel Teoh nrea-hased syslem**insl~lled** in 2003 to converturea to ammoni"- for injecling reagent ah<:;ld ofboiler economizer oullet and**high-d~sL** SCR. An OFA sYSlcm 

### was retrofitted in 1998CJ3). Source: Fuel Tech experience list da!cd 112812005; (Il)Bums & McDonnel1 internal dambasc. Northern Indiana Public Service Compony (NIPSCO) SchahferUnit 14 Crushed Coal, cyclone-fIre<!, opposed-wall-fired 1975 vinlage 

### 520 MWB&W boiler Urea/ammonia conversion for high-dust SCR, 

### 2004 slartup Boiler fires weslern subbituminous (PRE) cooL Commeroial Fuel Tech ure;l.-bascu syslem installed in 

### 2004 to convert urea !o ammoni. forinjecting reagent ahead ofboiler economizer outlet and high-dus! SCIL An OFA system was retrofitkd in 

### 2(){)0(\Jl. Source: Fuel Tcch**c.~pcricnce** lisl dated 1128/2005;**(l'~ums** & McDOIUlCU internal dolaha'e_

Bum' & MoDonncl1 A2_8 SquaTC B litreElemio CoopcrativeAPPENDIXA2 US. NO" ConlrolRetrofitProjects NOllBACfAnalysis Study



## ,

# ," TABLEA-3

- Low-DustPulverized Coal-Fired Boiler SCRInstallations

'CR UnitSize', Opecaloc

### IFaoj][ty',2 S[ac(np Ave"'gc NO" Emission 

### MW Oat.' Ral"" (IblmmBlu) 

### AEP/CardinalUni13' 5101103 0.74/0.34 I 0.135 

# "" CarolIna P&LiM.yo Unil 17 "/(0.36)/NIA 368,,2 Carolina P&URoxboro Uo1,4'" 5107101 0.57/0.26/0.081 372" 2 CinergylEasl BendUnit 1 410J/02 _/(0.28)/0.067 

## M' ConSlellatiun/Bnmdon Shores Unir I' (2001) OA7/0.33 10.126 

# '" ConslelialionJBr.mdon Shores Unit 2' (2000) OA5/0.3110.094 

# '" Dayton P&UKillen StationUnit2 11101/03 _/(0.48)/0.06 

# ,

# .. DynegyMidwesl Gen/HavaTlU Unit 6" (2000) 0.46 10.20 / 0.102 

# '"" PSEGPowerliC / MercerUni, I" (2005) _/(0_63)/NIA 

# ,,"
PSEGPower LLC/ MeTCOT Unit 2" (201)4) _/(0_16)/NIA 

# ,,"
BIlIIIS & McDonnell mlernal database. 2 Currenl fuel is eastern ormidweslernbituminous coal, ""cept Ha"ana ] _ US EPA Docket OAR-2002-0076-ll446 Teohnical Support DooUIueOl for BARTNOllLimits for Elecrr:io Geoerating Unit.<; Excel Sp,-eadshee1 611512005, o"""PI where oored. Dales in

## 0 are believed 10 be occuralo bulhave notbeenconfirmed. <

_ The three values aro "Prc-control avorngc·', "2004 3nIlIlsl average", and "2003 07;:)ne .,eason**av"",ge~** NO" emissionTOlo" as n:por1<:d to US EPA. Pre..:oulrOl and year 201)4 UIJIlua! average data as 'hown in US EPA Dode' OAR_2002·0076-0446 Technical SupportDooument fin BART NO,- Limits fo' Electric GL"Ilmlting Unil'l Excel Spreedshee, 611512005, posled 00 theirwebsite:**http://dockeLepa,gov/edkpubldo!EDKStafl''emDetailView?objectld~0007d48084562b.** Values shown 10pareotheses are year2003 OIIIIual avenoge whe", 201)4 data i' DO' Rvall.ble. Year 2003 and 2003 ozone seawndata is available from lhe EPA'. web'ite "' http;/Icfpub.ep;!.gov/gdmlinde".clin.iIIcludesapplication o[separnlcdoverfire airfor oOUlbustion No", control where applicable.

, - Generalornamepl,'e rating, Mnn:h 2002EneTID' InforrnaLionAdmioislr3tionrepon DOElEIA0095(2000). Aotual unit MW outpulrating may be higher or lowerIhan oameplate.

, _ This boil., has low_NO>< burno'" for combustioncontrols.

, _ Carolina POWCl 

### '!< Lighlplants li:<tcd bore have lwo boilus per unJ" rolal nameplole fo' Mayo is 736 MW, Roxboro i.145 MW; emission numbo", arc the .verage ofbothboilers

. • _ This boil., has low_NO,- bum." and ove:rfrre .ir for oombu'tion control,.

, _ Ths is preliminary data reported 10 lhe US EPA for 201)4 ozone season overage emission note. 10

_ Thi' OOilOT's ourrem fuel is belIeved to be SIIbbituminons ooa1. " _ Mercerhoilas li'tedhave 10w_dllS' SCR

### wilh,flue gas rehear. Unitsizeis approximate, nol nameplale. N/A compJolc 2004 owne seasOn dal3. is "'" avaiJRble. and 2003 ozone ,eason d'ta is not'epleseotative ofthe po"_SCRinstallation emissioo rate.

Square BUlle Elcolrio Cooperative A2_9 Burns & McDonnell

### NOxilACTAnal}'si, Srudy APPENDTXA2 U.S. NOx ConlrOl Retrofit ProjeCIS


### SELECTIVENON-CATALYI1CREDUC110N Pnlverizell coal_fired boilen; American Elcclrie POl'lcr (AEP) Pulverized Coal, cell-burner, opposed wall-fired B&W boiler CardiI1lll Unit I 1967 vinLage; Low NO, burners imlallctl in OolobLT 1998 600 MW (nominal) Brilliant, Ohio Fuel Tech urea-ba,ed SNCR installed in Oclober 19?8. Fuel Tech, DOE, EPRI-mcmber ulililies SNCR demonstration project. Te,ted in March_Al'riI1999, claimed 65% reduclion with LNRs + SNCR w/S 

### ppmNH, slip, (from 

### prc-LNB rclrofil basdine of 1.20 Ih/mmiltu*) down to 0.52 lb/mmBtu at 610 MW (100% MCR). SNC'Rrcduced NOx 31% below LNRs alone (0.75 IbfnunB!u ba"eline), al 610 MWg (100% MCR), 34% reduction at 75% MeR (450 MWg), and 41% reduction at minimum load (340 MWg, 55% MCR) ,,;5% ammonia slip("!, burning eastern bituminous coaL Urea-to-NOx NSR not staled. Source: Fud Tech experience lisL ,Iuled 112812005; 

### (l)lCAC White Paper, (17) 

### 2000 Fuel Tech**technic~1** 

### paper, *Riley Power (Babcook Power Illo) experience lisl 8116/04. Carolina Power & 

### Light (Progress Energy) Asheville Unil I Pnlverized Coal, front wall fired 200 MWe nB RileybOller 1964 vintage, easlcrnbiluminous coal, June 2000 SNCR starlup fuel Tech commercial SNCR inslJllation claimed 25% NOx reduction from low-NOx burne, 1'1/0

### OFA baseline of0.58lb/mmlltu (down to OA41b/rrnnBLu on SNCR ulonc). Urcu-lo-NOxNSll nol stated. (Also see FLGR + SNCR in"l.lIution summaries for pulveriud wal boilers). Source: Fucl Tteh experience 11Sl dale(] 1/28/2005. CJrolinu Powcr & 

### Lighl (progrcss**En~"Tgy)** 

### Pulverized Coal, Tangentially-fired Cape Fear Unit 5 1956 vinlage; caSlern bituminous coal 154 MW CE boik"T SNCR startup in 2002 Mobotec USA "Rotamix" ammoma-hased SNCR oy,km injects aqucous ammonia liquid into a high velocity**boo"tc~** 

### "cparalcu ovcrfrre air (ltOFA) system at the boiler. CP&L !cohnioal paper daimed to lowerNOx fromO.28lbfnunBtu bJSeline by43% to 0.16 Ib/mmBlu in 2002 with 5 ppm NIl, slip following the installation ofROFA in 2000. Overall rcduclion 73% from full-load pre·ROFA bJseline 0.60 Ib/mmBtu to 0.16IblmmBtulLOJ

. Mobolec claimed furtherNOx reduction was possible by injecting urea in place ofammonia,**~chieving** 

### 0.13 lbfmmBtu inslead of0.18 lbfLnmBtu, which would bc 54% deereose from 0.28 IbJmmlltu with ROFA alone, or 78% overall decrease("). Ammonia-to-NOxNSRnot staled. Source: (18) CP&L 2002 Technicul poper; (l9) Mobotec 200J technical paper. Curolina**POW~T** & 

### Light (Progress Enerb'Y) l'ulverized Coal,**Tangen~ally-lJred** 

### Cape FearUnit 6 twin_furnaoe (clght comer), ]958 vinlagc; eaSlern bilurninou" coal 175 MW CE boiler SNCR ",",tup in 2001 Mobolcc USA "Rotamix" ammonia-bused SNCR syslcm, injecls aqueous ammonia liquid into a high. velocity boo"ted separated overfire air ("ROFA") syslem at rbe boiler. CP&L lechnioal paper claimed 10 lo\'lCTNOx from 0.23 Ib/rrnnBtu baseline by 22% 10 0.18 IblmmBlu with 5 Wm NIl, slip following the mstal1alion ofROFA+SNCR in 2001(j,). Presentalioll slide graph shows no reduclion [orRornmix beyond ROFA alone al full loadNOx emission raLe ofO.231b1rrnnlltu. Ammonia·lo-NOx NSR nol slaled. Overall reduction 67% from full-load prc-ROFA baseline 0.54lb/rrnnBlu to O_IS IbhnrnBLu. Mobotec daimed further NOx reduclion waspO&liblcby injecting urea in place ofammonia, achieving 0.10 Ibfmnilitu inslcJd of0.18 IbirrunHlu, which would be 56% decrcase from 0.23 lblrrmilltu with ROFA alone, or 81% overall deoreaselL9l

_ Urc,Ho-NOx NSR no! Slaled. Source: tl8) 

### CP&L 2002 Technical paper; (!OJ 

### Moboteo 2003 technical paper.
Burns &. 

### McDoQ/lell A2_10 

### Square BUlleElocbic CooperarlveAPPENDIXA2 u.s. NOx Control Retrofil ProjecL' NOx BACfAnalysis Study



### Pulverized Coal, Tangentially-fired, 196D vintage; startup prior 10 

### 20DO



# '" SELECTIVENON-CA TALYTlCREDUCTIONcOlltinued 

### Pulverized cool 

### fired boilers Cinergy (fonnerly Cincinnati G&E) Miami FortUnil6 (Ohio) 163 

### MW CE boiler Fuel 

### Tech urea_based SNCR syslem, claimed 

### to ]owerNOx hy 35% from 0.55 IbJmmBtu baseline(I).(assume eastern bituminous ooal). Urea-lo-NOx NSR nol slaled. Source: Fucl**Te~h** 

### experience list dated 1/2812005, (J) 

### ICAC WhilePaper. Conectiv (fonnerly Delmarva Power & 

### Light) EdgemoorUnit 3 Pulverized Coal, Tangentially-fired, 1954vinlage 84 MW CE boiler mid-March 1996 startup; (assume eastern bituminous coal) Hamon Research-Cottrell supplied a urea_based SNCRsyslem. HRC**~Iaimed** 

### 35% NOx reduction with 

### less than 10 ppm 

### ammonia slip. Urea-lo-NOxNSRnot stilted. AnOlher source shows a 30% 

### reduction from 

### 0_541b1mmBtu baseline(I), Source: Hamon experience lisl (nollisled by Fuel Tech); (I) ICAC Whilc Paper_ Concetiv**([orm~rly** 

### Delmarva Power & 

### Light) Pulverized Coal Indian River Units 3 & 

### 4 (Millsboro, DE) Unil3 is fronl wall-fired, 1974 vintage 178MW and440 

### MW Unit 4 is turbo·fired opposed-won, 1980 vintage 

### B&W, DB Rileyboilers Spring 2000 startup (easternbituminous coal) HlIITlon Research-Cottrell supplied 

### a lJrel-baood SNCR system (not lisle<! byFuel Tech) on both units_ HRC claimed 35% NO

### xreductionwith Jess 

### than 5 ppm ammonia slip_ Urea_lo-NOx NSR not staled. 

### An-REI 1999 technical 

### paper shows 

### a pre-SNCR baseline of0.37 and O.44lbJmmBtu, respectively_

### I>OJ Another source lisled these unils as 

### having a pre-control NOx baseline of0_97 and 0.57 IbJmmBtu, and 2004 post-SNCR startup average of0.32 and 0_33lbfmrnBlu, respeclively. (1') 

### SoUrce: Hamon experience list (nct listed by 

### Fuel Tech); ('0)

### REI 1999 teohnical paper; (12) 

### US EPA**Do~kcl** 

### OAR-2002-0076-0446 Exoel Spreadsheet 6fl5/2005. Dominion Generalion (Virginia E&P 

### Co.) Pulverized Cool, Tangentially-frred Clover Station, Units 1 & 

### 2 

### (VA) ARB/CEboilers, 1995, 1995 vintage 2

.. 465 

### MW (easlern bituminous coal) Urea_based SNCR(Fuel Tech system) 1995, 1996 slartup (initial oommercial) Fuel Tech cluimcd NOx reduced by 25% from 0.321bfrnmBtu baseline (10 

### 0.24 IbJmmBm). Sour",,: Fuel Tech experience list daled 1/28/2005. Urea-to-NOx NSR not stated_ DynegyMidwcst Generation (formerly Illinois Power) Polverized Coal, Tangentially-frred Vennillion Station, Unit 1 1955 

### viIi.lllge 82 MW CE boiler, bituminous lllinois coal Mobolec USA "Rotamix" urea_based SNCR syslem withrotating opposed fired air (ROFA). Mobotec 2004 technical 

### paper claimed to 

### lower NOx.by 55% from 0221bJmmBtu baseline to 0.10 IbhnmBtu in April 2004 wilh urea-based RolaJnix SNCR and <:; 

### 5 ppm 

### CO. 

### NH, slip nmmentioned Overall reduction 83% [rom full-load pre-ROFA baseline 0_581bJrnmBtu to 0.10 lb/mmBtu(211. Urea-to_ NOx NSRnotstaled, Sour",,: (") Mobolec 2004 lechnical paper_

Square BUlle Eleclrio 

### Co0p0,"llve BUIn'l & 

### McDonnellNOxBACT Analysis Study AP:PENDlX A2 U.S, NOx Control Retrofil Projecl'

Pulverized Coal, from wall-fIred, 1952,1952, 1958 vinlilge (easlernbil. coal) SNCR slampprior 10 2000 

### Sh'LECTIVENON-CA 1'ALYJ1CREDUCTIONcORln/ue" 

### Pulverized**~OJd-fired** 

### boHers Easlern Ulilitic<**A"su~i~lcs,** Pulverized Coal, T<lJ1genlially"fircd Munl"llp**El~clric** Company 1959 vinlage Somcrsct Uni1 8 (Massaohusetl.s) Summcr 1995 <IUIIUp 112 MW CEbOller (caslem biluminous coal) Hamon Research-Coltrell supplied a urea-based SNCR (Fuel Tech system), claimed to lower NOx below O.38lblmmBlu (Mass_ MCT). Urea-lo-NOxNSRnol slatcd. Another :;ource listed 2R-IiO% NOx reduotion from n 0.49-0.89Ib/nmllllu \xlsclinc(1 ). Source: llamon expelience jj,t, Fuel Tech experience list daled 1/28/2005, ll)lCAC "While Paper. First

### Energy Pulverized Coal, TangeoliaUy-lired, Easllake Unil3 (Ohio) 1954 vinlage 130 

### MW CEboiler (wI division wall) 

### (easlern biluminous conI) Urea-based SNCR (Fuel Tech system) SNCR startur prior to 2000**Fu~l** Tech claimed to lower NOx fmm 20-32.5% from 0-34-0.40 lb/mmBlu ba:;elinc(l). UrcHo-NOx NSR notstated. Source: Fuel Tech experience list dalcd 112812005, [I) lCAC While Puper. Fiml**En~Tgy** Pulverized Coal, waH-fired, Sammis Unit 2 (Ohio) 1960 vinlage lSO MW Fosler "Wheckr boiler SNCR slartup Fall 1999 Urea-based SNCR (Fuel Tech system) (easlern hituminous cnal) Fuel Tech claimed to lower NOx from 25-30% from 0.45 lb/mmlltubaseline(l). Urea-ta-NCb, NSR nOI**S~lICd.** Snillee: Fuel Tech experience Jist dated 1/28/2005, (l)ICAC White Paper_ First Energy Pulver;7.ed Cmll, wall-fired, Sammis Onils 6 & 

### 7 (Ohio) 1969 & 1971 vinlage 680 

### MW B&W Universal Pressure boilers**(c~stcm** bituminous coal) Urea-based SNCR (Fuel Tech syslem) SNCR startup after 1999 Fuel Tech claimed to lower NOx fmm 25% from 0-381b/mmllm baseline. Urea-10·NOx NSR nol slated. SOllIce: fuel Tech**cxperienc~** list dated 112812005. New Eogland Power Company (NEPCO) SalemHarbor Station UnllSl,2&3 84 MWe x 2. &. 15G MWo B&W bailors Urea-based SNCR (Foel Tec" system) Fuel Techclaimed 6G% (50-75%) NOx reduction frombaseline of1.0 ± 0.1 (range 0,85-1.12) lbfmmlJlu, (which wonld**lowerNO~** to aroood 0.34±0.071b/mmBtu). Urea-lo-NOxNSR nol slaled. {TheseNOxrednclioo pen:emages may indudc imp"ol orlnw_NOx bumers). ' Source: F\lel Tech experience listdolod 1/28/2005, (lJ:iCAC Whir. Paper. (Also seeL"Nll iIlS",natiOO summaries forpulverized eool boile:r.;). Northe"st Ulililies (formerly Public Service ofNew Hampshire) Schiller Units 4, 5, & 6 Pulverized CoaV#6 Fuel oil, front_waH_fired 50 

### MWc X3FO:;lerWheelerboilers 1952, 1955, 1957 vinl""" Urea.hased SNCR (Fuel Tech system) Colombian bituminous coal August 1999 

### startup RJM: implemented Fucl Tech urea-based commercial SNCR inslallalion on all three boilers. 

### Burn, & McDonnell A2-12 Square**Bnu~** Eleclric Cooperalive

### APPENDIXA2 U_S. NOx ControlRetrofitProjeots NOx BACT Analy,i, Study



# "- RJM claimed 50% reduction namO.50 IblnunBlu pre-SNCRbaseline 10 0251bImmBlu for SNCRcoalfiring operation; NOx baseline 0.82 IblmmBtu prior 

### to RJM's LNB modifications installed in 

### 1994, 1992, & 

### 1994 (39% Tedllelion); Urea-lo-NOx NSR not slated. Fuel Tech claimed 30% NO" reductimJ for SNCR from baseline of 153 ppm firing 

### #6 fuel oil on Units 4 & 6 only, Source: R1M experience list, Fuel Tech experience list dated 1/28/2005. 

### SELECTIVENON-CATALYfICREDUCTIONco",inuetl Pulverized coal fired bollers Owensboro Municipal Utilities (KY) 

### Pulverized Coal, Tangentially-fired, Elmer Smith Unit 2 1974 vinlage 300 MW CEboiler easternbiluminous coal HomonResearch-Cottrell supplied an ammonia-based SNCR system but slaled nO claims for NO" reduction; (this project is nollisted in lCAC White**Papd'~.** 

### Annnoola-to-NOx NSR not stated. Source: Homon experience list. PECO Energy (formerly Philadelphia Electric Company) Cmmby Unit I Polverized Coal, frontWlllI-fired divided furnace 160 MWeB&Wboiler 1954 vintage eastern bitmninous coal RJM installed Fuel Tech urea-based SNCR 

### with lowNOx burner modifioations & OFA in 1999, June 1999 startup. RlMclaimed 29"/0 SNCRNOx reduction frombaseline ofO.351b/rnmBtu, downto 0.25 lbJrnmBtu wi!h urea NSR = 

### 0_8; RJM 

### provided burnermodifications ofB&W XCL 10w-NOx.burners inslalled 

### in 1994

## + OFA; !his reduced NOx from 0.50 to 

### 0.351blmmBtu (30% reduction) ,vithoul SNCR. Urea-to_NOx NSR not statedSource: RJM experience list; (lJ:[CAC White Paper. Exelon (fonnerly PECO Energy! Pennsylvania Electric Company) Eddystone Unils 1 & 2 Pulverized Coal Tangentially-fired, 318,333 MW each CEboilers 1999 SNCR startup, eastern bituminous coal FuelTech claimed 30% NOx. reduction from baseline 0[0.26JbJnunBtu. Source: Fuel Tech experience list daled 112SJ2005. 1954 vintage

Public Servioe Enlerprise Group (pSEG) Power LLC [formerly Public Service Eleotric & 

### Gas ofNew Jersey (PSE&G)] Hudson Stalion, Uolt2 Pulverized Coal, opposed-wall-fired, 1968 vintage 660.MWe Fosler Wheelerboilereastem bituminoUs coal March 1999 SUlrtllp Fuel Tech urea-based commercial SNCRinslallation claimed 25% (inilial)NOx. reduction for SNCR alone frombaseline ofO_651b/mmBtu (do"'ll to 0.49lb1mmBtu)_ Urea-lo-NOxNSRnol slated. Source, Fuel Tech experience list dated 1/2812005, also listed in (llJCAC White Paper. (Also see FLGR+SNCR inslllllalion summaries for pulverized coal boilers). Public Service Enterprise Group (pSEG) Power LLC [formerly Public Service Electric & 

### Gas ofNew Jersey (PSE&G)] Mercer Station (2)**twin-fum~ce** 

### boilers, 320.MWe each, DB Riley turbo-fired Unil I andUnil2 frontwalJ PC, wet-bottom (slagging ash) easternbituminous coal Furnace #11 & 

### #12 1960 vintage April 1999 slJrrtup Fumace #21 & 22 1961 vintage May 1999 slartup Fuel Tech urea-based commercial SNCRinslallation claimed ]0-35% NOx reduction from baseline 0[2.0 lbfmmBtu on SNCR alone, down 10 1,4IbJrrunBtIl_ Urea-to-NOx NSR not staled, Sql1llrC

### Butte Eloclrio Cuoporalive A213 

### Bums & 

### McDonnellNO"BACTAualysis Sluuy APPENDTXA2 u.s. NO" ControlRelrOfil ProjeClS

----_.. _------- 

# --
------ S'llIrcc: 

### Fuel Tech experi""ce list ualed 1/2&'2005; also lisled in ('1CAC White Paper. (Also 

### sec f'LGR+SNCR installalion summaries forpulvt.TIzcd cunl boilers) 

### SELECl1VENON-CATALYTICREDUCTIONwlI/inued**.Pulveri~ed** conl-fiHd builen Reliant Energy (formerly GPU Genco) Pulverized Coal (formerly Silhe, formerly l'enelec) Tnngcnlially-fired Seward:; 15 (PA) mid.1990's SNCR startujl Units 4 & 5 eastern hituminou, coal 62 & 156 

### MW CE boilers 1950 & 1957 vinlage Urea-buseJ SNCR (F\lcJ Tcch syslem), later installed an in_duct SCR Lo reduce 

### NH, slip. Fuel Tech claimed 10 10werNOx 35% for SNCR only (55% for combined SNCRISCR from 0.78 lb/nnnB Lu b,,,cline). Boilers have since been demolished and**r~l'laced** wilh CFBs. Urea-lo-NOx NSRnot stated. Source: Fuel**T~"Ch** experience lisl dated 1/21::12005, (l)rCAC While Paper.**Roohest~'T** Gas & Ek,,!ric Pulverizcll Coal, Tangentially-fired Ru"ellStation, Unils 1-4 (NY) 1948,1950,1953,1957 vintage 1 x 50 

### MW, 2 x 65 

### MW, 1 x 85 MW

## cn boilers e"stern bitnminous coal Urea_based SNCR (Fue) Tech system) SNCR startup prior 

### to 2000 Vendor claimed to lower

### NUx by 15-27.5% h-om 0.28

- 0.42lblrruuBlu basdines. Urea-to-NOx NSRnot stated. Source: fuel Tech experience list dated 1/2812005. 

### HYDROCARRON-ENHANCElJ

### AMMONIA SNCR (NO;rSIQrT") Pulverized coal-fired boilers TClUlessee Volley Authonty (TVA) Pulverized Cnal hvin-fumacc, l:1ngentially-fired, Kingston Power Sl<llion 

### (rN) 1955 vinwgc castern bituminom coal Unil9, 200 

### MWe CE boiler NOxStar"" sLllrlup Junuary 2002**DenlO",lra~on** ofNOxStarTM hydrocarbon--cnhaneed ammonia-based SNCR installation. Milsui Babcock clairne1l68% 

### NOx reduction from baseline of0.55 IbJrrunBtu down to 0.171b/mmBlu with boosted OFA and NOxSlarTM wilh <: 5 ppm ammonia slip; NOxStarTM alone reducedNOx by 53%!2l1; boosted OFA only reduee<l NOx from 0.55 to 0.45 lbJmmBlu (18% reduction). Anunollia_Lo_ NO>: NSR not staled. TVA's websile reportcd thaI "'an earlier "ernion ofNO"Star W"S inslolled at Kingston Fossil PlantUnit 9 in 2002 wirh mixed !'eSulls. NOx reductions were achieved, huttheboiler was damaged" (hltp:/lwww.lva.gov/environmentlrepolrs!envreporlslaer12003/cnv

_compliance.hlm) Source: (U) Mil,ui Babcock T**eehnie~l** p"JPcr, October200J.
Tennessee VaHey Authority (TVA) Pulverizcll Co"l, w"ll"fired Colbert Station (AL) 1955 vintage Unit 4, 192 MWe twin_furnace B&W bojlerwl FGReUSlern biluminous coal First commercial in.tallation ofNOxStarTM hydrocaroon,enhanced anunonia-basell SNCRtechnology. M;ISlli llabeockshowed 80% NOx reducLion from baseline ofO.50 10 O.iO 11)/mmBto; u,'ing< 0.1 % of lot:ll boiler hear input for propune inpul and 1% ortolal steam now generated inlhe boiler for lance cooling(2J); lOrN SNCR system startup. Ammonia-lo-NOx NSR nolstated. Source: (Z)) Mitsui Bahcock2004 Technical 

### paper.

Burns & McDonnell A2-14 Square Bune Eleclrie Coop<rntive

### APPENDIXA2 us. 

### NOx CoolIol Retrofil Project. 

### NOxBACT Aoaly,is Srudy

Pulverized Coal, opposed wall-fired cell-burner, 1969 & 1972 

### vintage eastern bituminous coal 

### REBURN

- GAS, CONVENTIONAL Pulverized coal 

### Hrcd boilers AlleghenyPower (formerly West Pennsylvania Power) Hatfield's Feny**Sta~on** 

### Units 2 & 3, 

### 600:MW (nominal) each (B&W 

### boilers) GE-EER Gas Rebum; 1999 5tartup (Unit 2) & 

### 2003 (Unil3) GE-EER Low NOxburners, boosled OFA, gas rebum system. GE-EER claimed 

### to 10werNOx up to 67% fromba,eline of0.60 lblmmBtu 10 

### 0.20 lb/mmBtu at fuJI load with rebum operation on Unit 2, 68% 

### from 0.62lb/uunBlU 10 

### 0.20 lb!mmBlu onUnil 3. No claims of percenlreburn fucl inclucled. GE-EER lec/mical paper shows approx. 35% NOxrcduction al600 MW 

### load with LNB 

## +OFAwlo rcbum fucl, and an addilional50% reduction to 

### 0.20 IblrnmBtu wilh rebum fuel!2'). B&W 

### added 20 OFA ports in 1994 per B&W's experience list. No NOx reducliou claims. SOUTce: Sept. 2005 GE-EER experience lisl; (2<) 

### GE-EER 2004 Technical paper. Unit 2 andUnit3 Jjsted in 1')DOE_ NETL Scorecard on Rebuming 611/2004 (from 2004 Reburn Conference). 

### REBURN

- GAS, CONVEN170NAL cOrlfi"""a Pulverized coal-fired boilers) Conectiv (formerly Delmarva Power & 

### Light) Pulverized Cool, Tangentially-fired EdgemoorUnit 4 1966 vintage, easternbituminous coal 160 MW 

### CE boilcr 1999 startup GE-EER Gas Reburn projecl added gas supply piping, metering, hangers, supports, reburn injeclors und cooling airpiping; OFA ductwork, injection nozzles and waH ports, field instrumClltation. No FOR or OFA boosIer fans. Vendor claimed 10 

### lowerNOx 

### up 10 

### 48% from baseline ofO.321bfmmBtu to 

### 0.16 lbfuunBtu) al full load with rebum operation. No claims ofpereClltrcbum fuel included. GE-EEIl. teclmical paper shows approx. 32% NOxreduction for gas rebtlm with4-mill operation al 

### 160 MW 

### load from 0.31 Ib/nunBtu LNB 

### + OFA baseline wlo reburn fuel (down to 0.21 Ib/mmBtu),;rnd 48% NOx reduction for gas rebum with 

### 3-mil1 operation, to 

### 0.161b/uunBtu (2<). 

### Source: Sept. 2005 GE-EER experience list: [2<) 

### GE-BER 2004 TecJmical paper. Listed in(')OOE-NETL Scorecard on Rebuming 6fl12004 (from 2004 Reburn ConfCTCncc) Dynegy (formerly Illinois Power) Pulverized Cool, Tangentially-fud Hcnnepin Unit 1 1966 vintage 71 MW CE boiler easlcm bituminous coal GE"EER Gas Reburn, 1990 startup (nO! eurrenlly opemling); GE-EER Orimulsion Reborn, 1997. 

### DOE Clean Coal demoru;!ralion project (included sorbenl injcction). Vendor claimed gas reburn 

### wIOFA lowered NOx 

### up 10 

### 67% from baseline of0.75 lbfnunBlu 10 

### 0.25 IbfmmBtu) al full load; 65% reduction 

### frombaseline ofO.75lb/mrnBtu downto 0.26 lblrnmBtu with subsequent Orimulsionreburn operation. GE-EER 2004 technical paper shows 18% gas rebumfuel yielded minimum NOx emissions(6). Another leclmical paper showed this 80 MW US 

### DOE Clean Cool demonstrationproject in January 1991- January 1993 loweredNOx by 67% from 0.75 IbfnunBtu baseline (10 

### 0,25 lblmrnBtu) with 18 percent 

### rebum 

### fuel(5). Source: Sept. 2005 OE.EER experience list; (6) 

### GE-EER 2004 Technical paper; I') 

### DOE-NETL 2004 Rebum Conference technical paper, and DOE-NETL Seoreeard on Reburning 61112004 (from 2004 Reburn Conference). (Also 

### see Conventional Oil reburn instaHation summaries forpulverized coal boilers).

Square Bune Electric 

### CoOI"'I1ltivc Bums & 

### MeDmmell

### NO" IlACfAnalysis Srudy Al'PENDlXA2 U.s. NO" Control Retrofit Projects
RERURN·- GAS, CONVEN110NAL cOllli1l11ed 

### PQlverized coal_fired boilers) AES (formerly New York Stme Gas & 

### Electric (NYSEG) Greenidg.e #6 (NY) Pulvcrizetl Coal, Tangcntially-fired, 1953 vinlage 100 MW cn boiler GE-EER Convcnlionnl Gas Rcbum, 1996 slnrlup Vendor claimed 10 lowerNO" 55% li'om 0.63 IhlmmBtubaseline 10 

### 0-28lb/mmBtu al fulllond with ,-cbum operation buniing c",lern bituminous coaL OJ< Research In,titute predicted would achieve 76% (down to 0.15 lb/mmBtu) "II 

### advanced gns ,-cbllm. GE-EER 2004 ledmica1 paper ,hows 23% ,-cbum fucl yic1<kd minimllm NO"**emis~ion,** 

### """md 0.23 

### Ib/rnmBt,i6). EPA's "Sooreoard on Rebuming 

### 6/1/2004" shows a 109 MW t-fired boiler (listcd as Greenidge Unil4) lowered NOx by 50% from 0.50 IblmmBlu baseline (10 0.251blmmBlu) wllh 10 percenl robum fuel (no longcr op"mling-) I'). Source: Sept. 2005 OE-EER experienoe list; ("l 

### GE-EER 2004 Tcdmical pnpor; r')DOE_NETL Scorecard on Reburning 

### 6/112004 (from 200411ebum Conference). Polomac Ekctric Power (formerly West Pennsylval1ia Power) ChalkPoint Slalion**Pulver;z~d** 

### Coal opposed w"Il-[rrc(I B&W boilers Units I & 2 1964, 1965 vinla.ge eastern bituminollS coal 

### 360 MW (nominal) GE-EER Gas Reburn, 2000 startup Vendor claimed 10 lower**NO.~** 

### up 10 43% and 45% from 0.60 Ib/mnilltubaseline to 0.34 and 0.33 Ib/mmBlU) at lull load wilhrebum**op~'ration,** 

### respectively. No claims ofpercel11 rebum fuel included. Source: 2002 GE-EER experience list. Listed in {')POE-NETL Scorecard on Rehuming 6/J/2004 (from 2004 Rebum**Confcrcn~c).** 

### Xeel Energy (formerly Pnblic Service Company ofColorado) Cherokee Unit 3 Pnlverizcd co.l, wall"fircd, 1962 vinl"ge 175 MW B&Wboikr western. bituminous coal DOE Clean Coal demonstmtion**proj~cl** 

### November 1992-January 1995 Gas reburn demmlslrntion performed with Dept. ofEl1ergy and Gas Research Inslitute 1992-1995. Existing boikT wilh 16 burners was retrofitled ,vilh low NO", burners and GE-EER gas rebum OFA, FGR, and reburn injeclors. Added OFA boo,ler fan, 800 hp flue ga, recirculalion fan for inj"<:lion mass**mom~'TIturn,** 

### for inGreased gas injeclion JTlliSS momentum (which was subs"<]u""11yremoved). TI,e CGR installation portion has since been decommissiOl1ed. Vendorclairned 10**low~r** 

### NO" up 10 64% from baseline of0.73 Ib/mmBlu to 0.26 lb/mmBlu) at full load WiIh rebum operalion. GE-EER2004**l~~hnical** 

### pape"" "hows 15-20% rebum fuel yielded minimum NO" emissions{'J. A 2004 DOE-NETL technical paper showcd thisprojecl achieved 0.46lblrrunBw NOxemissions wilh ]owNO", burners alone (31% reduction), furtl1er rc<1uced NOxby 44% wilh 12.5 perccnl,-cburn fud'). A2001 DOE-NEIL leohnical pap"T claimed a NO" reduction of65% at an average reburn gas heal inpul of 18% oftotal boiler fuel**inpu~** 

### with and wilhout FGR- DemollSrralcd 70% NO" reduclion al higher rebum inpulr"les.**R~feITc<1lo** 

### lechnology as GR-LNB. FGR was added for gas injection mmnemUm bul was subsequently removed to reduce fuel input. P'I Source: SepL 2005 GE-EER experience lisl; I') (iE-EER 2004Technical paper; (') DOE-NETI 2004 Rebum Conference lechnical paper:ll1dDOE-NETL Scorecard on Rebuming 6/1/2004 

### (from 2004 Rebum Conference);{''lDOE-NETL 2001 Technioal paper; also in (9) 

### DOE 1999 Topical Report Number 

# ".

BllIn' & 

### McDonnell A2-16 

### Squ.reBUlle Electric CooperaliveAPPENDIX A2 U.S. NOx Control RClrofil ProjeClS NOx BACT AnalYSis Study



# "

" 

### REBURN-OIL, CONVENTIONAL Pulverized coal-fired boilers Dynegy (fonnerly JIlinois Power)**Pulveri~ed** Coal, T3Ilgentially-fired HennepinUnit 1 1966 vintage, eastern bituminous coal 71 MW CE boiler 1997 slartup GE-EEROrimulsion Rebum system wi OFA, claimed orimulsion rebum loweredNOx up (0 65% from baseline ofO.751b/mmBtu 10 0,261blmmBtuat full loadwith Orirnulsion rcbum operation (installed after gas rebum was <IemooslI1lted in early 1990's). No claims forpcrcent reburn fuel indnded. GE-EER 2004 technical paper shows ro"J6reduction withsubs"'luent Orimnlsion reburn (6), Source: GE-EER experience list; (0) GE-EER2004 Technical paper. Orimulsionnot mentioned in (l) DOE-NETL 2004 Rebum Conference technical paper orDOE-NEfL Score<:ard on Reburning 611/2004 (from 2004 Reborn Conference). (Also Sec Conventional Gas Rebum installation summaries for pulverized coal boilers).
New BrunswiCkPower Coleson Cove, Bunker CIOrimuision-lired, opposed-wall St. John, New Brunswick, Con.da 3x 350MWB&WBoilcrs Sixteen new low-NO;.; oil/Orimnlsionburners, eigbtrebum burners, nine SOFA ports, two combustion air booster funs, reburn and OFA waH penelI1ltion openings, OFA windboxes, ductwork, dampers, and accessories were added(1). Another technical paper showed this reburn system lowered NOx by 78% from 1.0 lblmmBtu baseline to 0.22 IblmmBtu at 25 percent rebum fuel input(l). Source: (7) B&W 2004 Tcclmieal Paper;(') DOE-NETL Scorecard on Rebuming 61112004 (from 2004 Reburn Conference). GeorgiaPower Pulverized Coal, Tangentially_fired Scherer Unit I 1982 vintage 887 MW CE boiler 2000 oil rebum slartlJp GE-EER Oil Rebum syslem, claimed to 10werNOx from baseline ofO.361blnnnBtu. GE-EER 2004 Teelmicalpaper shows reduction 

### up to 48% (to 0.19 lblmmBrn).t 800 MW loadwith oil rebum opemtion. No claims ofperoent reburn 

### fuel included(2<J. Source: Sepl2005 GE-EER experience list shows this as a coal reburn project with eastem bituminous coal, reducing NOx emissions 33% from 0.36 

### to O.24Ib1mmBtu; (2<J GE-EER 2004 Technioal paper. Not listed in (') DOE_NETL Scorecard on Reburning 61112004 (from 2004 ReblUU Conference). 

### REBURJIl

- COAL, MICRONlZEiJ, CONVENTIONAL**Pulveri~ed** coal_fired boilers AES (fonuerly New York Stale Electric and Gas MlIliken Slation Unit I) Cayuga tangentially-fired, pulverized coal, 1956 vintage 148 MWe, CEboiler eastern bituminous coal GE.EER mioronized coal rcbumsyslem 1996 startup (still operating) US DOE Clean Coal demonstmtionproject fromMarcb 1997-Apri1199910weredNOx with this reburn system by 29% from O.3S1bhnmBtu baselineto 0.2SlblmmDtu at 14 percentrebum fuel input(l). Not listed 

### in GE-EER's experience list nor in their 2004 technicalpaper. Source: (» DOE_NETL 2004 Reborn Conference technical paper and DOE-NETL Scorecard on Rebuming 611/2004 (from 2004 

### Reborn Conference).

SquareBune Electric Cooperative A2-17 Burns & McDoIIDeJ(

### NOxBACT Analysis Smdy APP£NDLXA2 U.S. 

### NOx Control RerrofilProjects



### LOW**NO~** 

### BURNERS (ReplacemeJ.t 01' modijicllliOJls) wim,dwlo OVERFJREAIR conrfnued Pulverized**c,,~I-fired** hoilers 

### DynegyMidwest Gelleration (fOJIDCrly Illinois Power) Pulverized Coal, wall-fired**Hav~na** 

### StallOll, 

### Un;' 6 J978 vrnt"ge**~60** 

### MW B&W builer, bituminous lllinois coal 

### GE-EERprovidedmo<li.fiealions to 

### the origm"l B&W dual_register bUffier" nnd an 

### OFA syslcm in 2000. VClldor claimed fun loadNO

### xwas unchanged Irom 0.381blmmBtu b.,clillo. Source: GE"EER Experience list 

### 211102. (Also sec low-dust SCR insLallation lisl for pulverized coal boilers) DynegyMl<Jwest Generation (formerly Jl1inois**1'0W~T)** 

### Pulverized Coal, Tangcnlial1y-fired Vermillion Station, Unill 1955 vinlage 82 MW CE 

### boiler, bituminou., Illinois coal Tl,;S 

### rolaling opposed fire"ir (Mobotec USAROFA) syslem w"s insLalled inJuly 2002, as part ofa ''RoLamixn 

### SNCR 

### +ROl'A system, wilhoullow-NOx burners. Mobotec 2004 technical paper claimed to 

### lower full10ad NOxby 62% 

### from 0.581blmmlltu baseline to 0.221b!mmlllu in July 2002 (wilhollt LNB Qr SNCR). (21) 

### SOUlce: (2]) 

### Mohotec 2004 tcchnLcal paper. (Also see SNCR ITIsta]1ation summaries fOJ pulverized coal boik-rs). Georgia Power Pulwrized ooal, opposed wall-fired, Harlee Branoh Uni' [ 250 

### MW B&W boiler, 1965 vintago 2003 startup Harleo Branoh Uml2 ]59 MW Riley boiler, 1967 vintage 1998 startup B&W provided 24 DRB-4Z low NOx bumel'" forUnit 1 

### B&W bOller, 

### 24 DRll-XCL low NOx hurner< for Unit 2 Rileyboiler (believe .,outheast eo"sllignite IS primary fuel). Source: B&W'

### s experience list. No NOxreduction claims. 

### Kansas City**1'0W~"f** 

### & Light Pulwri'l.<:d coal, opposed wall-fired, 600 MW B&W boiler Hawthoffi Unit 5 30 bumers, 2001 vml<lge, (powderRiver Basin coal) B&W provided 30 DRB-4Z low NOx burners and II OrA ports wirh thc ncw boiler. Source: B&W's experience list. No NOx reduction claims.

- New EngJaml Power Company (NEPCO)

Salem Harbor Station Pulverized Coal, fronr waU-fired, Units 1, 

### 2 & 3 

### 1952, 1952, 1958 vintage (eastern bil. coal) 84 MWe 

### x 2, & 

### 156 MWe B&W boilers LNBs slartup in 1995, 1995, and 1993 Riley claimed Unil 1 LNlls reduced NOx emissioru by 57% trom bascline of 1.10 Ib/nnl1Blu down [0 

### 0.42 lb!mmBtu; Unit 

### Ts LNBs achieved 42% NOx reduction from a baseline of0.95 lb/mmBtu down to 0.55 lb!mmBtu; Unit 3'" LNBf; 

### achieved 60% NOx reduction from a baseline of 1.051b!mmBtu down 10 

### 0.421b/mmBtu. Source: Riley Power (Babcock Power InG.) 

### 8116104 experience lise (Also see SNCR im:taHation summaries for pulverized coal boilers). Northeast Utililies (formerly Public Service 

### oINew Hampshire) Shiller Station Pulverized CoalJ#6 Fuel 

### oil, front-wall-Dred Units 4, 5, & 6 1952, 1955, 1957 vintage 50 MWe x 3 

### Fosler Wheeler bol1e'" 

### RJM provided (6) 

### Low NO, burner modifications per boiler in 1994, 1992, & 

### 1994 respectively; LNBs reduced NOx 43% from 0.85 10 

### 0.48, 50% from 1.0 10 

### 050, and 51% from 0.82 10 

### 0.40 Ib!mmBtu. Source: lUM experience lis!

BllIlIS & 

### MeDonndl A2_22 SquareBulle Electric CooperativeAPPENDIX A2 US_NOx ConlmJ RelrofitProjects NOx BACfAnalY";" Study



### LOWNO., BURNERS (Replacement ormodifications) 

### wialld

### wit> Of/ERFlREAIR confi'lUed Pnlverlzed coal_fired boilors Potomac Eleotrio Power (fonnerly West PennsylvaniaPower) ChalkPoint Station Pulveriud Coal opposed wall_fired Units 1 & 2 1964, 1965 vinlage eastern bituminous cool 360"M\V (nominal) B&W boilers DB Riley (now BaboookPower) CCV type low NOx burnersretrofitted in 1993 and 1994, rcspectiveJy_ Vendor claimed 10 lowerNOx up 10 52% and 50% from 1.35 and 1.40 lbhnmBtubaselines (1o 0.65;md 0.70 lblmmBtu, assumed at full load). Source: Riley Power (BabcockPower Inc.) 8/16104 experience list. (Also see Conventional Gas Rebum inslallation summaries for pulvcrized coal boil=). Xcd Energy (fonnerly Public Service Company ofColorado) Cherokee Unit 3 PuJveri:zed coal, wan-fired, B&W boiler, 16 burners, 1962 vintage 175 MW Oclober 1992 baseline lesling sl.arled (western bituminous coal) Inslalled (16) FosterWheeler Controlled Flow/SplitFI3IIle lowNO, replacement burners as part ofa DOE Clean Coal Technology gas rebum demonstralionperformedwith Gas Research Institute 1992- 1995. UncontrolledNOx wi original B&W flare-type burners was 0.73IblmmBtu. ReplacementLNBs (assuming OFA included) reduced NOx 37% 10 0.46IblmmBtu(2..lJ. Source: (lSI DOENETL 2001 Technical paper. 

### A.2:2 

### Technical Literature References fotU.S. NO" Control Retrofit Projeets:
(I) SNCRWhile Paper, Institule ofGean Air Companies, Inc. (ICAC), SNCR Committee, May 2000, Fnel Tech website httv:/lwww.fueltechnv.comlpdllTPP 534.pdf l'lREI 2001 Teclmical Paper ·'Design and**Demonstra~on** ofRich ReagenlInjections (RRI) Perfonnance ForNOx Reduction al Conneoliv's B.L England Station" by Marc A. Cremer and Bradley R_ Adams, Reaclion Engineering Inlemational, David C. O'Connor, Electric PowerRe5earch Institule, Venkala Bhamidipall, ConectivRL England Station, andR. GiffordBroderick, RIM C0'll0ralion,**p~esented** at the 2001 US EPAJDOFJEPRHv:lEGA Symp05inm on SCRand SNCRs, Chicago, IL, AUglJ5l20·23, 200!. (REI website htlp:/fW'iVW_reaction-eng_comidonwloads/rri mega.pM 

### P)REI 2002 Technical Paper "Demonslrlltion ofRichReagentInjection CorNOx Conlrolln AmerenUE's Sioux Unit I" byMarc A. Cremer and BradleyR. Adams,**Reac~on** Engineering International, David E. Boll, AmerenUE, and David C. O'Connor, Electric PowerReseurch Institute, presenled atthe US DOE Conferenoe on SCRJSNCRfor NUx Control, Pinsburgb, PA, May 15-16, 2002; and



### REI 2003 Technical Paper "Improved Rich Reagent Injection (RRI) PerformanceForNOx Control 

### In Coal Fired Utility Boilers" by More A_ Cremer and Hnafeng D. Wang, Reaction Engineering International, David E. Boll, ArncrenUE, Edmillld Schindler, RJM CorpOIlllion, and Edmundo Vasquez, RMT, Inc., Alli""t Energy C0'll_, presented al2003 U_S. DOE Conference on SCR and SNCR forNOx Control, Pittsburgh, PA, October29-30,2003. (dJ RET 2004 Technical paper,**'·Evalua~on** ofCos! Effective Non-SCR Options forNOx Control In PRB Fired Cyclone Boilers" byMarc A. Cremer and David H. Wang, and BraclleyR. Adams, Reaction Engineering Inlermtional, David E. Boll and KermelhR Stnckmeyer, AmerenUE, presenled at lbe Western Fuels-SympOSium, 19"' International Conference on Lignite, Brown, and Subbituminous Coals (fonnerly Low-llimkFuels), Oclober 12-14, 2004, Billings,:MT_
Square Bull<: Elecme CoOV'mnive AW BIlIIIS & McDonneUNOxBACf**A~aly,i5** Study APPENDlXA2 U.S. NOx Control Rerrolll Projccl'



## * REJ 2005 Technical paper"NOx Emissions Below 0.151h/Mblu Achieved in a Cyclone-Fired Boiler Using In-Furnacc Control" by M.**C'rcm~T,** B. Adams, and A Chiodo, Reaction Engineering lntemalional; 

### C. Giesmann, 

### K. Stucloneyer, and J. Boyle, AmerenUE, presenled at the PowerGen InlematlonJ12005 conference, December 6-H, 1005, 

## r.as Vegas, Nevada. ('lDOE-NETL 1004Tedmical Paper "Rcbuming l'rojects in the Department ofEnergy's Clean Coal Technology Demonstration Program", by Al Mann and TomRuppel, Parsons Corporation, and Tom Sarkus, National Energy Technical Laboratory, presented at the 2004 DOE·NETT. Conference On Reburning for NOx Control, Morganlown, WV, May IS, 2004. A rebnnHelated doenment 

### (an updated version ofa po>1er lrom lhe May 18 Conference) is titled ·'Scorecard on Rebuming 61112004" by Al MJnn and Tom Ruppel, Parsons Corl'oflltion, availabk on-line**~l: http;l/www.n~ll.doe,govfpubliculiomjproceedings/04iNOxiposterslRebumillg%20Scorecard.lldf**  (6) GE Energy 2004 TcdmicJI paper "Reburn Techllology Applioation Gnideli",:,,", by David Moyeda, GE Enermr, presented atthe 2004 DOE-NETL Conference on Reburning for NOx Control", Morgantown, WV, May 

### IS, 2004.
('l B&W 2004 Teclmical Paper ·'B&W's Rebnming Experience", by H. Farzan, G. Maringo, A. Yagiela, 

### A. Kokkinos, Babcock& Wilcox, Co., presmted at the 2004**DOE-Nb~IL** Conference on Rebnrning for NOx Control, Morguntown, WV, May lS, 2004. (This da.ta is n duplicate ofa more detailed lechnical paper published earlier, ·'B&W's Advance On Cyclone NOx Control Via Fuel and Air Staging Technologies", by H. Farzan, G. Maringo, D.W. Johnson, and D.W. Wong, Bubcock& Wilcox, Co., 

### C-T. Bcuro, Eastman Kodak Company, anu S.E. Brewster, Tennessee Valley Authority, presented at thc 

### EPRIDOE-EPA Combined Urility AJr Pollntant Control Symposium, Atlanta, GA, Aub'Ust 16--20, 1999). ('jB&W casehistory "ll&W Cyclone Rebum Leads to NOx Reduction, Wisconsin l'ower & Light Co. Nelson Dewey UnitNo.2" (fromwebsite http://www.baboockcomipgg/ps/casebislorics.hlml, dated 1997).
(9) DOE Topicnl ReporlNumber 14 '"Rebuming Technologies forlhe ContIol OfNitrogen Oxides EmiSSions from Coal-FiredBoilers", conduoled under separate cooperative "greements between the U.S. Dcpllrtmont ofEnergy, the Bubcook & Wilcox Company, Energyand Environmental Re,earch Corporation, and New York State Electric & Gas Corporalion, May 1999. IlO)Technical Paper "Predictions ofFLGR al Conunonwealth Edison·s Joliet Unit 

### 6"' by NGB Technologies, posted on their website: http://www.ngbteoh.comlsnbmt-gos/proJljoliel rcsults,hlml
(ll) REI 2001 Technical puper "CFD Evalnation ofFuel Lean Gas Rcbum 

### (I'LGRTM) "nd Sclective NOll_ Catalytic Reduction in Owensboro MlITlicipal Utilities' Elmer Smilh Slation"', by DavidH. Wang, Marc A. Cremer, and Bradley R. Adams, Reaction Engineering International, K.D. Frizzell, Owensboro Municipal Utilities, and G.C. Dusatko, Sargent & LlITldy, 2001 US EPAIDOE MEGA Symposium on SCR and SNCRs, Chicago, IL, Angust 20-23, 2001. l"lUS EPA Docket OAR-2002·0076-0446 Technical Support DllCnment for BARTNOx Limits for Electric GeneralingUnits Excel Spreadsheet 6/15/2005, poslcd on their website: h!!P:lldocket.epa.gov/edkpnb/do/EDKStaffilcmDetaiIView?objectTd-090007d48084562b (lJ!Bums & McDOImdl internal databJse.

Burns & McDonnell Al-24 Square**Bu~e** EleCirlc Coopcram'eAPPENDIXA2 

### u.s. NOx ControlRetrofitProjects NOx BACTAnalysis Srudy



### I") Technioal paper "Operating Experienoe 

### and Future Challenges With SCR Applioations", by Gerd Beckmann and Clayton 

### A. Erickson, Babcook Borsig Power, Inc., presented atPowcr-Gcn International 2000, November 14, 2000, Orlando, 

### FL.
(I') DOE 

### NEllTechnical paper "Control ofNitrogen Oxide Emissions: Selective Catalytic Reduction (SCRl", Clean Coal TechnologyTopical Report Number 9, July 1997, posted on lheir weooile: h®:I/www.nell.dce.govfpublicationsfolhersflopicalsftomcaI9.pdfs. ('0 SCR White Paper, Institute ofClean Air Companies, lnc. (ICAC), SCR Commillee, November 1997, htlp:/Iwww.annnoniapm.comlArnmonia%20LibrorvINOx%20RcduolionfInslituleo/0200:£%20 Clean%20Air"/o20Co SCR.pdf, linkedto R...M. Teohnologies websile hUp:l/'-V\VW.rmteoh.nctiartlcakhtm

(l1] Technioa1 paper "Cardinal Unit I Large Scale Selective Non-Catalytic Rcduction Dcmonstration

'" Project", by PatrickM. Malone, American Elcctric PowerScrvicc Corp, and Dr. William H. Sun, Fuel Tech, presented at the lCAC Forum 2000, March 23-24, 2000, Rossyln, VA. (l')CP&L 2002 Teclmical Paper "Rotating Opposed Fire Air (ROFA) ami SNCR", by :Mark Shilling and Gary Tonamakcr, CarolinaPower & Light Co., presented atthe 2002 DOE-NETL Conference onUnburned Carbon on Utility Byash, May 14, 2002" Pittsburgh, PA. (lO)Mobotec 2003 Technical Paper "Injeclion ofUrea through IhcRotamix System to Obtain TmprovcdNOx RcductiOIl'':'.by John Ralston and Edwin Haddad, Mobolec USA, Ino., presented at the 2003 U.S. DOE Conference on SCR and SNCR for NOx Control, Pittsburgh, PA, October 29-30, 2003. (l°iREI 

## 1999 Technical Paper "CFD Modeling ofSNCR Performance 

### in Conecliv's Indian River Units 3 and**4~,** by 

### M. Cremer andM. Heap, Reaction Engineering International, M. Zoccola, Conectiv, and V. Ciar1ante,**.~hmon-Research** Cottrell, presenled al DOE Conference OIl SCRand SNCR for NOx Control, May 20-21, 1999, Pittsburgh, PA. (21)Mobotec 2004 Technioal Paper "SCR Levels ofNOx Reduction with ROFAand Rotamix (SNCR) al Dy!1egy's Vermillion Power Station", by KristopherA. Coombs, Sr., DyncgyMidwC1ll Generation, and Jay S. Crilley, Mark Shilling, andEdwin Haddad, Mobotec USA, Inc., presented at the 2004 SlackEmissions Symposium, Clearwater Beach, 

### FL, Jnly 28-30, 2004. (21) Milsui Babcock 2003 Tei:lmical paper, "NOxSlar rM Plant Demonstration, October**2003~,** by K.W. Morris and G. Hcssc1man, Milsui Babcock (US), presented at the 20(l3 U.S. DOE Conference on SCR 

### and SNCR for NOx Control, Pillsburgh. PA, October 29-30, 2003. ("') Milsui Babcook 2004 Technical paper, "Installation ofNOxStarTM SystematlVA Colbert", by Keith W. Morris, Mitsui Babcock (US), presenled at the Coal-Gen 2004 Conference, July 28_30, 2004, Overland Park, KS. (") GE Energy (fonnerly GE-EER) 2004 Teclmical paper "Experience with Reburn forNOx Emissions Control", by Don Engelhardt, Roy Payne, David Moyeda, Blair Folsom, GE Energy, presented al 

### the 2004 DOB-NEIL Conference On Rebuming for NOx Control, Morgantown, WV, May 18, 2004, ('S)DOE

### NEIL Technicalpaper "Evaluation oIGas Reburning and Low-NOx Bnrners on a Wall-Fired BoilerADOE Assessment", dated February 2001. DOEINEfL_200l/l143, posled ontheirwehsite; hlro:/lwww.netl.doe.govfcclclresourcesfpdfsfeercolGRLNBPPA.pdf.

SquareBune Electric Coopomtive Burm & MoDonneU

### NO" BACT Analysi, Sludy**----~ .~.** **~---~** 

### APPE.,"DIX AI 

### U.S. NOx Control RelrofilProjecl'

1"1 GE Energy (formerly GE-EER) 2004 Technieal paper "Powerplaol mosaics: paving lhe way 

### to 0.11 IblMMBlu withoul SCR", by**B1~ir** 

### Folsom, GE Euergy, published inlhe March 2004 issue ofModem Power Syslerru;. 1'7) NGB Technical P'lper ''Fuel Lean Gas Rebmn (FLUW"') Tedmology Jor AchievingNOx Emi"ions Compliance: Application to a Tnngenli"lly-Fired Boiler", by Richard D_ Frederiksen, Werner J.A. Dalrrn, and GrelarTryggvason, NGll Technologies, Inc., Bernan] P. Bre,,", RogerGlickert, andJosepb A. Urieh, Energy Systems Assoemtcs, and John M. Pratapa' and Rohert V. Serauskas, Gas Research In,litute (GRl), presenLcd allhe 1998 Joinl AmericmlJapane,e l'lame Research Committee InLemalionul Symposium Environmental Control ofCombuslion Processes: Innovative TechnologyTowards [he**21~** 

### Cmturv, Maui, Hnwnii, October] 1-15, 199R. 

### (")2001 Technical Paper "Application ofl'ud Leau**G~s** 

### Rcbum Wilh SNCR On A 198 MW Coal-Fired Ulility Boiler" by David Killen, Carolina Power & Light Co., John M_ Boyle andJohn H. O'L:ary, Fuel Tech Inc., presented at the 2001 US EPAfDOEJEPRI MEGA Symposium on

# sca and SNCR" Chicago, IL, Augnsl 20-23, 

### 200

### J_ !"'rcdmical paper ''First Commercial Jru;tallation ofAmine Enhanced Fuel Lean Gas Rebum On 

### Unils [ and 2 at Public Service El,.,tric & Gas**Mcrc~T** 

### Station", by Andrew F. Gomez, l'ublic Service m,.,lric & Gas Company (PSE&G) Mercer Generaling Station, Alexander S. DainoFfandJohn H. O'Lcory, Fuel Tech, hlC., andRobert Schrecengost., Energy SyS1CIIlS Associates, presented al the 2000 DOE-NETL Conference on SCR nnd SNCR for 

### NOx Control, Pittsburgh, FA, May 17-18, 2000.

Bums & 

### McDonnell A2-26 

### Squore**Bu~e** 

### Electric Coopermive

### APPENDIXB 

### EERCREPORT Ash Impacts on SCR Catalyst Performance

# ASH IMPACTS ON SCR CATALYST PERFORMANCE

f'Teparedby: Sleven A. Benson, Ph.D. Energy & Environmental Research Cenler Universily "fNonhDokota POBox9018 Grand Forks, ND 58202·9018

00101><,2005



# ,TABLEOFCOI\'TENTS



### LIST OFFIGURES II LIST OFTABLES 

### III EXECUTIVE SUI.\1I\iARY ES-l INTRODUCfION 3 

### INORGANIC COMPOSITION OFLOW-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 FACILITY 7 History ofFurnacc Sbg-;:ingIFonling 9 Advanced Boiler Perform.nceIndice,

_ , ' '.H

.._ , 9 

### ASH-RELATED IMPACTS ON SCR CATALYST PERFORMANCE 16 

### FuJl·Scale Slipslream Tesling _. .... _ __ .._ _ _ _16 SCRAshDeposit Characterization

__. . 19 SCRDepositFormationMechanisms

__ .. . _ _ 20 Low-Temperature Pyrosulf.tes

_ _ _ 31 

### Condllsion: SCRIs Notfeasible FOR NOx REDUCTION atM. r. yonog .34 REFERENCES 36LIST 0" "[GORES Figure I. Variability ofseleclc'tl comlitucnts in COTC analy," datooose**p~vi<1ed** by ENI Coal, LId.•nd Minnkola co.1 Jalab","

_ _ . ________-._ 3 Figure 2_ OveraH processes ofash**dcpo~ition** typical ofa lignite- or subbitumillolls-fircd boiler__

__ _ _ _ .. 

### .... ._ 6 Figure 3_ 

### T'50 frequency dislribution for all Coal Quality Management System (CQMS) dala, of

_ _ _ .._ _ _ _ _ _ __.. .._ .12 Figure 4.

## T", dislnbu1ion for HA Seamcoal

.._ . FiguTc 5. T"o dislTibution [orHE se.mcoal FlgIlTC 6_ T**~IO** distribution fur KC seamcoal

.. .. .. __ IJ

.... .......... 13

_____________.._ ..... 14 Figure 7. Vmiations 

### in the delivered coal quality during a test bum period

.. Figure 8. Weight changes for PRB-blend coal ash exposed to Hue gases and ammonia at three temperatures
..__.. .. _ _ .. _ 14



### _ _ 21 Figure 9. Weight changes for PRB-blend coal ash exposed [0 flue gases and ammonia with and wilhout SCR catalyst presenl_

_ _..... .... .._ .. 22 Figure 10. Catalyst pres""re drop atB"I<lwin Station at 0 !o 2 montllS ofoperation 22
Figure II. C.lalysl pTe'5Ilre drop at Columbia Slation al 0 10 2 mo"ths ofopermloll

..... ...__.. ........ 23 Figure 12. Cata1y.,tI'r",,,ure drop .1 Coyole Stalion at 0 10 2moutbs ofoper.rion

.. Figure 13. Pictures of**eala]y~l** inlet after abOlll 2 monlhs oflesling at each plant

_ .. _24 Figure 14. Pictures ofealalyst inlet afler about 4 months ofexpnsure [0 nue gas andparliculate__

_ _ _.. __ _ __ .. _ ..25 Figure 15_ SEM iII1flges of...,h colleoted Oll c,ulysrsurfilee al thc Baldwin Slation .fief6 monlhs ofexposure .. ._................... .._ 26 FigUTI: 16_ SEM iII1flge, of",h collected on c,mlysl sllrface al ihe Coyole SLlInon .1lcT4 monlb, ofe"po'UTI:

_ __.. _......................... . 28 Figure 17. Compari,onofeulT.inoo ",1, and deposiled ash on calaly'l for Culumbia Siallon

_.. .. JO Figure IS_ MedklnismofSCR catal}"ltblindingvi' lhe formatIon ofsulf"lc" and carbonalc' (modifiodarLerPritohard .nd othe" POD 31> LIST OF TABLES 

### Table 1. Characteristics and Indices Calculated for Selected CenterLignite Samples Table 2. Advanced Index Values fOr Other Coals (12)

iii 

### 12 13

## '-.'ASHIMPACTS ON

## sca CATALYST PERFORMANCE


### EXECUTIVE SUMMARY The ash deposition behavior ofthe.lignites from North Dakota is the most complex and severe ofany coals in the world, and installation ofcatalysts for NO, reduction is going to be plagued with problems. The Center lignite fired at the MillonR. Young (MRY) 

### Power StatIon is highlyvariable in abundance ofvarious types ofash/slag-fonning components. Ash-forming components consist ofinorganic elements (sodiwn, magnesium, calcium, and potassium) associated with oxygen functional 

### in the organic matrix and mineral grains (quartz, clays, carbonates, sulfates, and sulfides). Upon combustion, the inorganic components undergo chemical andphysical transformations thatproduce intermediate inorganic species 

### in the fonn of inorganic gases, liquids, and solids. The 

### alkali and alkaline-earih elements combine with minerals during combustion, resulting in low-melling-pointphases that cause a wide range oJ fIreside deposition problems. In 

### addition, the alkali and alkaline-earth elements also fonn very small particles that are carried into the backpasses ofthe combustion system ITlld reactwith fiue gas to form sulfates that can cause deposition, blinding, and plugging problems in selective catalytic reduction (SCR) systems. This report analyzes these problems, and concludes that SCR is not a feasible option to control NOx emissions at MRY Power Station because ofthe high sodium levels present 

### in the coal. Following is a list ofthe 

### key problems thal are associated with Center lignitc which have not been overcome and, in our opinion, make the inslallation of SCR at lhe :MRY 

### plant technically infeasible [or

### NOx control.



## » Blinding ofCatalyst Pores by High Sodium Compounds 

### X High levels ofalkali aud alkaline-earth elements present in the coal flred at the 

### MRY plant produce small particles tbat reaclto fonn sulfates thal blind the catalystpores_ The high levels ofsodiurn in the coals combined with calcium will produce lowmelting-poinl eutectic sulfate compounds that win form and melt inside the pores ofthe catalyst.

• Alkali and alkaline earth 

### sulfates are enhanced by cyclone fired system. The cyclone fIring results in partitioning ofthe ash betweenbottom slag and the body ofthe boiler. The sulfate forming materials are more concentrated in the ash as a a result ofcyclone**firin~**



### • Sulfule fonnalion is enhanced by lhe presence ofan SCR catalyst; this**accel~tes** 

### the sulfation reactions, causing blinding oflhe catalyst.

• The sulfate reactIons arc more severe at:MRY because ofthe high temperature where an SCRwould be installed. The higher temperature increases the rate offonnation of sulfates and rate ofpore plugging.

• The testing conducted by the GelTIlans found catalyst deactivation ITllublinding occurs when firing coals with lignIte orbrown coals that have ashes that are rich in alkali and alkaline-earth elements

..

### • The findings by the Germans were confirmed by recent SCR ealalysl slipstream lesting that showed significant evidence ofsodium and calcium-rich sulfate formalion Ulat fill and ping the ealalyst at both lignile- and snbbitumiuous-coal-firedpower plants. The resulls oflhis fCcentlesting showed Ihal the presence ofsodium signilicanlIy enhanced Ihe fOlllialion ofbonding ofpartides and more rapid sulfalion, filling ofpoTes, and rapid incrcage in pressure drop across Ihe calalyst.

• Deposit carryover, or "popcorn ash," plugging Ihe lop oflhe SCR cal.<llyst is a signilieHlll problem because ofibe extremely high deposition rates ofme CenlercoaL When firing Centercoal, deposil..'l fOTm ,on various parts oftheboilerrequiring continuous sooiblowing_ The soolblowing ofupsIream heat-exchange equipment-...vill cnuse deposil fragments 10 

### be camed back to the SCR calalyst., resulting in plugginl;- In 

### nddition, l!uring sootblowing ofthe SCR ealalyst, Ibe entralmnent ofdeposit fragmenl.s along with the soolblowing media will result 

### in significant erosion orlhe catalysl surfaces.

• Recent lesting wilh subbituminous and lignitic conls indicaled a significanlly higher level ofpore filling anl! plugging in the calalyst exposed 10 

### lignile ash as compare to subbituminous coal ash. The catalyst pores as well as Ihe calolyst surface 

### in the lignile tests were completely coaled with a sodimn calcium sulfate material, while only pore filling was found in the subbilnminous coal testing, The pressure drop across Ihe cal.<llyst exhibited tor lignite was 4 10 

### 5 limes greater Illan Ibat fonnl! fo, a catalyst exposed 10 

### subbituminous coal osh. The plugging occurred over a 1000 hourtest period.

l> 

### Cold Side SCR Installation High-sodium lignite coal from the CenlerMine Hagel A and B scam coal produces significant levels ofhomogeneously condensed sodium sulfale Ihatpass through the ESP nnd wei scrubber.

• 

### TIlese small particles have been shown to pass through a wet scrubber and will accumulate on surfaces oflail-end SCR systems. The accnmulated malerials require sootblowing to remove theparticulate and will result in incfCaged opacily

.

•Liquid pyrosullate malerials lit 

### temperatures as low as 535°F from sodium snlfale malerials occurs in coal-fIred power systems and is well documented. Pyroslilfates will fann and cause blinding oflail-end SCR devices_ Tn addition, SCR systems are known 10 

### calalyze the formation ofSO] from SOl_ The presence orso, signilicanlly enhances the formation ofIhe pyrosulfitles.



# ,

# ", ASH IMPACTS ON SCRCATALYST PERFORMANCE INTRODUCTION Ash produced during combustion ofcoal in conventional power systems is a major problem that results in decreased efficiency, unscheduled oulages, equipment failures, and increased cleaning. The manyways in which the detrimental effects ofash manifest themselves in a boiler systcm include fireside ash deposition on heat-transfer surfaces, corrosion and erosion ofboilerpmts, poor slag flow, and production offineparticulates that 

### are difficullto collect. Decades ofresearch have been conducted to develop a bellerunderslnnding ofthe chemical and physical processes ofash fOmJation and deposition in combustion systems. Overviews ofash, related issues and compilations ofwork bymany investigaLars can be foundby referring to 

### the work ofMehta md Benson 

### (1), Schobert (2), Baxter and 

### DeSollar (3), Couch (4), Williamson and Wigley (5), Benson and others (6), Benson 

### (7), Bryers and Vorres (8), Raask (9, 10), and 

### Benson (11). 

### This work has led 10 

### a detailed understanding ofash fOmJation and behaviorin combustion systems as well as thc development ofpredictive methods (12, 13). The chemical composition andphysical characteristics ofash-fonning or inorganic components (mineral and organically associated elemenls) ofthe fuel(s) fired have 

### an influence on the following processes in the combustion systems:

• Firing conditions such as cyclone, pulverized coal, and low-NO, burners

• Transforrnatious ofcoal inorganic compouents to ash 

### particulate and vapor-phase SPCCles Boiler design characteristies, including number oIburners, radiant seetion area, tube bank spacing, access for cleaning, and number ofsootblowers

• Ash transport to henl"transfer surfaces in utilityboilers

• Erosion wear and sticking

• Ash deposit growth and impact ou heat transfer

• Ashblinding and plugging ofselective catalytic reduction (SCR) catalysts

• Ash deposit removability The ash deposition in North Dakota lignite-fired powerpIa.uts is amajor problem that impacts all fireside surfaces oIthe powerplant. The ash problems are due 10 

### the variable and complex nature ofinorganic components associated with lignite coals (2). Upon combustion, the inorganic compouents undcrgo chemical and physical transfoJlI1ations !hatproduce inl.ennediate inorganic species in the fonn. ofinorganic gases, liquids, and solids. Duriug the gas-eooling processes in the boiler, the gas-phase species condense and the liquid-phase materials solidify. The abundance ofthese gas-phase and liquid materials entrained in tbe bulk gas flow is 

### highly dependent upon coal composition and system operating conditions. The inorganic materials are traIlsported La heat-transfer and catalyst surfaces by diffusion, electrophoresis, thermophoresis, 

# ,

### and inertial impaclion. The particle sticking amI accumulntion rates are dependent upon the quantity ofash and the abundance and viscosity ofthe liquid-phase components. 

### In hightemperatnre regions ofthe boiler, high-Iemperalnre sodium--caIeium-aluminosilieale liquid phases ad as the slicky material, causing deposit initiation, growth, IDld development ofdeposit strength. As the temperalure ofIhe flue gases decreases, the condens.1tion and reaction ofnamevolatilized species playa nlllra significanl roJa in the fonnation of**deposiL~** 

### fi:um li!>'rile conIs. The fOlllmtion ofsodium mdlor calcium magnesium sulfales dominales the deposit**accumul~tion** 

### mechanisms allower temperatures. The aluminosilicatc phases arc dominant above aboul 1800"F- Below about 1800"F, Ihe slilfate phases become slable, with <In optimum tempcrahlre offornmlion ofabout 1400°F, and Can fonn at lemperaturcs as low as 300°F. The mosl significant problems thal prohibillhe successful operation ofSCR catalysts to lignile coal is Ihe formalion oflow-temperature sodimn--calcium-magnesium sulfates and phosphales Ihal will form on the surfices ofcatalysts and the carryover ofdeposils that will plug the catalyst opening:;, resulting in increased pressure drop and decreased efficiency (14--16)_


### INORGANIC COMPOSITION OFLOW-RANK COALS lnorganic elements in coal occur as discrete minerals, organically associnted calions, and calions dissolved in pore water. Thc fraelion ofinorganic componenls thaI are organically associntcd varies with coal rank. Lowcr-ranhd**~llbbilUmino\lS** 

### and lignilic coals have high lcvels ofoxygen, which act a3 

### bonding sites for calions such as sodium, m<lguesiu\Jl, calcium, potassium, strontium, and barium (other minor and trace elements may also be present in**U1i~** 

### form). 

### In higher-ranked coals, bituminous and anthrncitc, inorganic componcnts consisl mainly ofminerals. Mineral grains are usually Ihe mosl abundanl inorgnnie eomponenl in coaL The major mineral groups found in coals include silicates, aluminosilicnles, carbonales, sulfides, suIfales, phosphalcs, nnd some oxides. The behavior ofash produced during coal combustion is related to 

### the abundance, size, and associalion ofmineral grains in the coal. In addition, Ihe association ofthe mineral grain with the coal maLrix influenCES the**temper~ture** 

### and gaseous environment Ihe mineral is cxposcd to during combustion. A mineral associated with the organic part ofa coal particle is said 10 

### be included. A minerallhat is not associated with organic malerinl is referred 10 

### as excluded. The behavior of Ibe organically associalcd clements, those elements thal are alomically dispersed in the coal malrix, mnsl also be measured as 10 

### Iheir abundance in the coal. The organically associated elements will reael and interact with the other ash-forming conslituents during eombuslion. The Cenler lignile is higWy variable in abundance ofvarions types ofash/slag-fonning constituents. Ash-fonning components In the Centerlignile are oftwo lypes. TIle firsl fonn may constitule up 10 

### 50% oEU1c ash and is derived from inorganic elements (sodium, n13gJlesium, calcium, and pOlassium) associaled with oxygen functional in the organic malrix onhe coal. The second type consisls ofmineral grains (sand, clay, limestone, and pyrilc). The minerals are discrete particles ofash-fomring species and the sources ofsilicon, aluminum, iron, titanium, and minor amounts ofthe clllcium and potassinffi_ The Cenlar lignite fired at the Milton 

### R. Young (MRY) planthas been examined eXlensively because oEilS problem wilh ash behavior. Analyses

### '" ofas-fired and drill core samples have been conducted. The mean and the range ofselected components are sho'IVII. in Figure 1. The results iudicate that both the abundance ofash and the abundance ofmajor oxides in the ash vary significanUy. 

### In addition, the abundance ofalkali and alkaiine-e:Jrth elements (Na and Cal varied dramatically. Variations in Si were found to be the most significant. 

### High levels ofCa andlor Na were found for lower-ash coals as compared 

### to high levcls ofAl and Si associated with higher-ash coals (17, 18)_

00
- c 00 

## • < 0 ;0 --- - - - ---- - -- - - 

# • 00

00 -------- - - --- '" - 

### .. - 

# " 00 - ---- ----- - - 2 00 

## f--

- - -- -- --- ---

# --t-I-- 1-- 0 

# • w 00 

# '" I 

# I

•**~- ~-**  AI,o,
-**~- ~.** **~.-** 

# - 

# -- SiD,- 

# '" 

# .- """,I:,,,,e 

# _. 

# .- •• d,,,,I>0,,, da"''''''''

Figure 1. Variability ofash and selected constituents in core analysis databaseprovided by BNi Coal, 

### Ltd. and Minnkota as fired coal analysis database,

The variability ofthe ash-forming components has been examined for the approximately 5000 samples characterized to date. Wide variations in ash contents and the major ash-fonning constituents are observed. During lhe mining processes, !heinorganic components are mixed, and some ofthe extreme characteristics are diluted (17).

INORGANIC TRANSFORMATIONS AND ASH FORMATION The inorganic coal components Wldergo complex chemical and physicallransformations during combustion

### to produce intermediate ash species. The inorganic species consist ofvapors, liquids, and solids. The partitioning ofthe inorganic components during combustionto fonn ash intermediates depends upon the association and chemical characteristics oftbe inorganic components, ilie physical characteristics ofthe coal particles, the physical clurracteristics oflhe coal minerals, and the combustion conditions. The physical transformation ofinorganic constituents depends on the inorganic composition ofthe coal and combustion condItions_ The inorganic components can consist of organically associated cations, mineral grains lhat are included in coal particles, and excluded mineral grains. There is a wide range ofcombinations ofmineral-mineral, mineral---coaJ,

### mineml--cation--coal, and mincral-mincrnl- cation--coal assoc;alions in coal. Thcsc assoeialions are unique to each coal sample. The physical tmnsfOimations involved in fiyash Jonnation include 1) coalesccnce of individual mineral grains within a charparticle, 2) shedding ofthe ash particles from !he snrfaee ofthe**ch~rs,** 

### 3) incomplete coalescence due to disintegration ofthe char, 4) convective lnmsport ofash from the char surface during devolatilization, 5) fragmentation oflhe inorganic mineral particles, 6) [onnation o[cenospheres, and 7) vaporizalion and subsequenl condensation ofthe inorganic components upon gas cooling. As a result ofthese intcractions, lhe ash has a bimodal size distribution. The submieron componenl is largely a**re~llll** 0 

### fthe condensation offlamevolatilized inorganic componenls. The mass mean diameter orthe lllTgerparticles is approximately 12 to J5 j.1m, depending upon the COol and combustion conditions. The larger-size particles have been called the residual ash by some investigators (19) because these ash particles :resemble, to 

### a limited degree, the original minerals in the coal. Processes such as ash mineral coalescence, partial cOi1lescence, ash shedding, and char fragmentation during char combuslion and mineral fragmenlalion, all play an importantrole in the size and composition ofthe final fly ash. Loehden and others (20) and Zygarlieke and others (21) indicate lhatlhree potentialmodcs for fly ash gcncration can bc used to deserihe fly ash**particle-si~.e** 

### and composilion evolutiou. TI1C first, ·'Jine Emit," assumes that each mineral grain forms a fly ash particle and that the organically associated elements Jom] 

### fly ash particles ofless than 2 !-lIn. The second, ''total coale8cence," assumes one fly ash pmticle forms per coal particle. "The third, "partial coalescence," suggesls that the fly ash composition and particle size evolve beeausc ofparlial coalescence. The transfonnations ofexclnded minerals m-e dependent upon !hephysical characteristics ofthe mineraL Excluded minerals such as qUoltz (Si02 ) can be carried throughthe combustion sySlem with i[8 angular slruclUre still intact. Excluded clay minerals can fragment duriug dehydration, mel!, and fonn cenosphercs. TIIC behavior ofcxcluded pyritc depends npon its morphology. Some ofthe pyrite maybc present as framboids. Frnmboidal pyrite may fragmcnt more easily lhan massive pyrite particles_ Iu additiou, the decomposilion ofpyrile is very cxothermie, and it transfonns to pyrrhotite and oxidizes to FeO, Fe3 0" and Fe2 0J during combustioll_



### ASH DEPOSITION ON HEAT-TRANSFER AND OTHER SURFACES EXPOSED TO ASH AND FLUE GAS TIle characteristics ofa deposit depend upon the chemical and physical characteristics of the intermediate ash species, gcometry ofthe system (gas Ilow patterns), gas lemperature, gas composition, and gas vcloeity_ Figure 2 ilJu8trale8 the ash deposition phenomena in utility boilers. A8h panicle accumulations occur via transport ofparticles to the fireside surfaces (heat u·mlsfer, ceramic materials, Sllpport materials, SCR catalysts, baghouse materials, and ESP wires and plates) and sticking ofthe particles. The transport mechanisms important for ash deposition includc small-particle mechanisms forparticles less than 10 ).1m thal involve !hermophorcsis, electrophoresis, and vapor-phase and small-particle diffusion; and large-particle mechanisms for particles greaterthan 10 ).lIn 

### thal involve inertial impaction. The ability oflargerparticles to stick depends upon the quantity and viscosity oflhe liquid phase on thc particle surface.

## '"

...,,'cI:**,,~,.** C.'--"A''',



### '" "c.. "y,.-- 

### Thermophoresis is a phenomenon thaL involves Lhe transport ofvery small particles as a result ofa Ibermal gradient from hot gases Lo cooler surfaces. Electrophoresis is the lransport of particles because ofa difference in charge. Vapor-phase and small-particle diffusion occurs in lhe boundary layernext 10 the surface and resulLs in lransport ofash lo the surface. Inertial impaction is a larger-particle phenomenon where the particles are ofa sufficient size and density lo leave airflow patterns around the tube and impinge upon the surface ofa lube or deposit. DeposIls thal fonn in high-lemperature regions ofthe boiler, such as the radiant secllon, are called slag deposils. Deposits thal fOlm in lowcr-lempcrature regions ofLhe boiler, such as in the convective pass on steam tubes and lower-lemperature surfaces such as SCR ClItalYSts, are called fouling deposits. Slag deposits are usually associliled wilh a high level ofliquid-phase components and are exposed to radiation from the llame. This is a description that many researchers usc lo aid in classification ofdeposits since some engineers caH any type ofdeposit "slag"" Slag deposits are lypically dominated by silicale liquid phases, but may also conlain moderate to high levels ofreduced iron phases such as FeD and FeS. The liquid characleristIcs of the silicates are highly dependent upon the quantities ofNa, Mg, Ca, K, and Fe ash on the silicates_ 

### In addilion, the inilialing layers ofslag deposits may consist ofvery fine particulate and can produce areflective ash layer_ This phenomenon is especially evidentwhen high organically associated calcium subbituminous coal is fired. These coals produce small CaO particles that usually fonn the initiating layers_

. -Fouling deposits fonn in Lbe lower-temperature regions ofthe boilers and, in most cases, do not conlain the high levels ofliquid phases thal are usually associated with slagging-type deposits_ Fouling deposits contain lower levels ofliquid phases as compared to slag deposils. The fouling deposit liquid phases usually consistmainly ofsulfaLes thal bind lhe particles together_ Fouling deposits typically form as a result ofthe reaction ofgas-phase sulfur oxide species with particles rich in alkali and alkaline-earth elemenls. 

### H-1!&.iL-'>

### :;,,-'_!J~ 

### R I 

### y"L':' Iltd

...

# lD**-;;=.,..~** 

# - ;.;., c'**'-'-~** 

## -;,-01

..;;;:;:;:: -_. - ,.\**-""'~"** 

## ",

DO**I-,~"_-r-,,,_** 

### -**,_~7~"""""** 

### I,","

.."- 

### ASEt-RELATED EXPERIENCES AT MRY FACILITY The MRY 

### is a minemouth electrical generating plant locatednear Center, North Dakota The station consisls oftwo units: Unit I, rated at 276 MWg, began produclion in 

### J970; Unit 2, rated at 506 MWg, began production 

### in 1977. Both Dnits I and 2 are equipped with B&W cyclone-firedboilers; lhe Dult 1 boilerhas seven cyclones, lIIld the Unit 2 boilerhas lwelve cyclones. Annual station gross generalion is approximately 5.5 million MWh. BN! Coal Ltd. is the sole coal supplier for the MRY 

### Slalion_ Coal is mined from the ncarby Ceotermine, which cOIlsisls ofthree dislinct scams varying from 

### 2V.-9 feet thick. Coal is stripmined using two draglines and is loadedwith front-end loaders and dclivered to lhe planlwith bottom-dump haul trucks. Annual coal production is 4_3 million tons per year.

# ,

# , ilf!


# , o 

# j


# , 8 

# " 

# i

" " o 

# "

### History ofFurnace SlaggingIFouling Prior to 1991, besides annual mn.intenance outages, load reductions and forced outages due to furnace slaggingjfonling were the largest cause ofproduction loss. 

### In 1985, operating guidelines were established thatreduced furnace slaggingjfouling, including deslagging outages scheduled every six months. 

### In 1991, a 3-monthboiler cleaning cycle was proposed and initiated... The goal ofthis program was to increase annual generation bynJ.Jining the units at higher sustained loads and scheduling boiler-cleooing oUlages at3-monlh intervals_ However, furnace slagginglfouling continued to have a significantimpact ou plant operalions_ Success was measured in the number ofproduction days between boiler-cleaning oulages_ During the mid-1990s, a major outage every third year was scheduled for each unit. 

### In addition, Unit 1 cleaning outages were scheduled for So-90-dayruns (four cleaning outages per year), and Unit 2 cleaning outages were scheduled for 65-75-day runs (five clcaning outages per year). The problem was that furnace and conveetiou-pass surfaces gradually become coated with ash deposits, which, over time, sootblowers cannot remove. Some ofilie contributors to the ash deposits were as follows:

• Organically associated sodiumis aprimary contributor to deposition problems. Sodium is 

### vaporized 

### in the cyclones and condenses on other ash particles, causing them to become sticky and deposit at the furnacc exit. The problem is associated with sulfaie fonnation and occurs in the convective pass, including the economizer_ Samples show that sodium in the ash varies from 0_6'Yo-13_0%_

• Organically associated calcium is another component that causes deposition problems. Unlike sodium, calcium does not produce a vapor-phase component. Calcium does react with silicate (derived from clays) to cause low-melting-pointphases that produce wall deposits and deposits in the high-temperature regions ofthe convective pass. Calcium also produces very small particles that will be transported to heat-transfer surfaces, resulting in the formation of thin, light-colored layers ClIlIed reflective lIllh. These smallparticles ofash are carried through to the backpasses where they are sulfated and can combine with sodium to 

### cause the formation ofstrongly bonded sulfate-based deposits. Samples show lhar calciumin the·ash varies from 6_8'%- 24.0%.

• Clay minerals and quartz

- Centerlignite can contain high levels ofiJlite, which has a J:3 AI;Si ratio and high levels ofpolassium, both ofwhich cause wall slagging and high-temperature fouling. Quartz and otherclays can significantly contribute to the mass ofthe deposits. Samples show that ash content varies from 5.00/.,-25.5%. Advanced Boiler Performance Indices Advanced indices areused to relate the coal characteristics as detennined hy complltercontrolled scanning electron microscopy (CCSEM) and chemical fractionation to nsh behaviorin a coal-fired utility boiler (12), Fuel performance is estimated in terms ofslag flow behavior, 

# ,

### abrasion amI erosion wear, wall slagging, high-temperature silicate-based convective pass fouling, lind low"tcmperature sulfate-based convective pass fouling. The following indices arc used to assess the eITects ofash behavior on utility boilerperfonmlllCe:

• Convective-Pass Fouling Indices Sulfation Index: Indicates the propensity ofdeposit to fonn in the convective pass ofthe utility boilerin Ihe lemperature range from 1000°_1 750"F. This index is based On the availability ofalkali (Na and K) and alkaline-earth (ea and Mg) elements 10 react with S02 and 

### SO, to form sulfates_ The sulfates are the primary materials Urnt cause particlc-toparticle bonding iII high·calcium coals. The sulfates are Ihennodynamieally stable at temperatures below abontl650Q

### F. Index values range from 1 (low) to 10 (severe). Silicate Index: Indicates the propensity ofdeposits to fonn from 1600o _2400°F. This index is related to the fonnatiou ofdeposits in which the silicate material is the primary component thatbonds the deposits together. The in/ormation used to 

### derive the index iucludes the size ofthe minerals such as quartz and clay minerals, availability ofalkali and alkaline-earth elements, and viscosity ofthe silicate liquid phase.ludcx values range from I (low) to 200 (severe).

• WaterwalJ Slagging Slagging Index: Indicates the propensity ofa deposil to 

### fonn on the radiant walls from 2000" 3000"F. The basis oIthe slagging index is the size ofthe minerals (especially the illite, quartz, and p)Tite), association oflhe calcium (calcite can contribute lo slagging), and viscosity ofthe silicate-based liquid phase. Index values range from 1 (low) to 

### 20 (severe).

• Wear Indices Abrasion Index: This index indicates the potential for wear offuel preparation and handling equipment. The wear is related to the hardness ofminerals in the coaL The primary minerals ofconcern include quartz and pyrite. The index values range from 0.1 (low) to 

### JO (severe). Erosion Index: This index indicates the potential for wear ofboilerparts due to the impaction offly ash panicles_ "The erosion indelt is dependent npon the size oftbe ash/mineral particle, size ofthe particle, and velocily oIthe particle. The index values range from 0.1 (Jaw) to 1.0 (severe).

• 

### Cyclone Slagging Index: 'illis index provides infolllmtion on the slag [low hehaviorin cycloues_ The factors that arc included in this index include the partitioning ofthe ash in the cyclone based on size and association ofthe ash-fanning components in the coal. The partitioning ofthe ash between the slag and enlnuned ash can significantly influence Ihe .flow behavior oIthc slag. Standard panitioning eriteriahave been developed to provide the composition ofthe slag. The composition is used to estimate the viscosity ofthe slag as a function oflemperaturc. The index values have several ranges as follows: I (low viscosity), 1.5--2.5 (optimum viscosity), >3.0 (slag freezing). W

### • Strength Development Index: The strength index is based on the ability ofthe deposited materia] to develop strength. Strength development is primarily dependent upon the abundance and viSCOSity of the liquid-phase components in the deposits. Index values less than 0_25 indicate tilatthe material 

## will produce weak: deposits; index values of 0.25-0.34 indicate weak-to-moderate-strength deposits; index values of0.34-0.41 indicate high-strength deposits; and index values >0-41 indicate flowing slag. Indices were calculated for a range ofcoals from the Centermine, and the propensity Ior ash deposition in various portions ofthe boiler indicates wide variations, as shown in Table 1_ The BNI numbers indicate the location in the seams where the coal origiuated: Kinneman Creek seam (KC), Hagel A 

### (HA), and Hagel 

### (BB). Each seam has a different distribution ofminerals and organically associated elements that can have a significantimpact on the formation of deposits in the system. Comparison ofCenterlignite to subbituminous andbituminous coals ITom otherregions ofthe UnIted Slates, shown in Table 2, indicates significant differences in the potentiallo form deposits in theboilers. 

### In all cases, the lignite (not the worst coal from Center mine) from the Centermine has n

### high propensityto produce deposits as compared to lhe other coals_Anotherindicalion ofthe variabIlity oflignites can be illustrated based on the calculation ofthe temperature where the slag flow would occur. This is defIned as the T250 temperature, where the slag viscosity is 250 poise. Frequency distributions ofthe T150 values for alllhe dala for coals analyzed are illustrated in Figure 3_ Calculations ofT250 values for 1212 samples obiained,.!i:om the Centermine database (J7J 

### were made using empirical relations derived from CCSEM and chemical fractionation data and knowledge ofhow ashpartitions in the cyclone. Figure 3 shows abimodal distribution 

### in the T250 based on the Urbain equation calculations. The primary mode was at avalue of2000°F. The secondarymode was at about 2700"F. The results indicate that many ofthe coals have a sufficiently low T250 for good slag (]ow_ However, coals with T250 

### at 2700°F are nol suitable for maintaining good slag flow_ Figures 4 through 6 illustrate the variations in T250 for the various seams ofcoals characterized_ The HA and HE seam coals appear to have large numbers ofsamples, with T250 values at or near 2000"F. The KC seam coal, as illustrated in Figure 6, has extremely high T250 values. Based on these data, the KC coals are not favored relative to the slag flow behavior oflhe**~h.** 

### Frequency distributions ofcyclone slagging index values indicated signifIcant variations in slagging potentials ofcoals mined from the three seams, KC, HA, and HE. This information proved particularly nseful in planning the mining and firing ofcoal from the KC seam. During a July 1999 test bum, the composition ofthe cores was used to examine and illustrnte the variability ofthe delivered coal quality based onbasc-to-acid mtio calculated from the ash composition. Figure 7 shows the variation in the base-to"aeid-ratio and the scam where the coal was loaded.. The base-la-acid ratios were calcula!ed from core data that corresponded to the location In the seam where the coal was mined. There is a significant variation in the baseto-acid mtio for the coals. The coals that have the highest base-to-acid ratio are typically from the HA seam. HB seam coals generallyhave an intermediate base-to-acid ratio. KC or top-seam coal has the lowestbase-to-acid ratio. Lower base-to-acid-ratio coals typicallyproduce slag wIth high viscosities.


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### Table 2. Advanccd Index Values for Olher Coals (12)

Advanced ltldices Cyclooe SI.ggiog lodex Conveclive Pas, Fouling Silicale Sulf.te 

## won Slagging Index Erosion Index Abrasion Index



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### FigureJ. T"o ireqnency distribution for all Cool QualiLy Management SysLcm (CQMS) data, 

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### Figure 7 shows the sequence ofdeliveries beginning on July 6 ami ending on July 12, 2004. During Lhis peliod, the majority ofthe coal delivered was from the IrA scam, followed by KC, and HB. Most ofthe deliveries alternated between KC and HA. Figure 6 shows several instances where significant quantities ofKC coal were delivered, on July 6 through July 9. The quanlity ofKC coal delivered will have the pOlentialto increase the viscosity oftlm slag and result in poor slag flow from the cyclones.



### ASH-RELATED IMPACTS ON SCR CATALYST PERFORi"lANCE Ash-related impacts On SCR catalystpcr[ommnee will depend upon the composition ofthe coal, Lhe t}'Pe offiring systems, Due gas temperature, and catalyst design (14-16, 22)_ The problems currenlly being experienced on SCR catalysts includc the following:

• Formation ofsulfate- and phosphate-based blinding materials on the surface of catalysIs.

• Carrying ofdeposit frdgments, orpopcorn ash, from otherparts ofthe boiler and depositing on lop ofthe SCR eatalysL._ Licata and others (14) eonducled tests on a SouLh African and German Ruhr coal and found that the Gernlan Ruhr coal significantly increased the pressure drop across the catalysi .;::; because ofthe acctunulalion ofash. They found that the Gennan coal produced a highly adhesive ash consisting ofalkali (K 

### and Na) sulfates_ In addition, thcy reporled that thc alkali elements are 

# '! in a water-soluble fonn and highly mobile and will migmte throughout thc catalystmaterial, reducing aCLIve Sites. The water-soluble fonn is typical oforganically assoeiatel! alkali elements in coals. The Gennan Ruhr Valley coal has about 9.5% ash and 0.9 % S On an asreceived basis, and the ash consisls mainly orSi (38_9%), 

### A1 (23.2%), Fe (11.6%), and Ca (9_7%), with lower levels ofK (1.85%) and Na (0.85%) (IS). Cichanosicz and Muzio (16) summari7:ed the experience in Japm and Gennany aud indicated lbat the alkali elements (K 

### aud Na) reduced the acidity ofthe catalyst sites for tolal alkali contenl (K

### +Na+Ca+Mg) of80/0-15% oftlle ash 

### in Enropean powerplants. They also found that alkaline-earth elements such as calciumreact with S03 on the catalyst, resulting in plnggillg ofpores and .1 

### decrease in the ability ofNI-b to bond to catalyst sites. The levels ofcalcium in the coals that caused blinding rangel! 

### >'; from 3%--5% ofthe ash. The mcclmnisrns forthis t}'Pe onow-temperature deposition bave been examined and modeled in detail at the Energy & 

### Environmental Research Center (EERC) in work termed Project Sodium and Project Calcium in the early 1990s; however, the focus ofthose projects was specific to primary superheater and economizcrregions ofboiJers and not SCR systcms (22, 23). Deposit buildup 0 rthis type can effcctively blind ormask the catalyst, diminishing its reactivity for converting N02to N2and water aud potentially creating increased ammonia slip (14). Arsenic and phosphates, which are not UnCOmmOn in low-rank coals, may also**pl~y** 

### a rolc ill caLalyst degeneration_ Arsenic is aknown calalystpoison (14) in applications such as calalytic oxidation for pollution control. Phosphotes can occnrin 10w-lemperahIrc ash <lep(lSits to creatc blinding effects, and they also oecur with arsenic and can cause catalyst. poisoning (23).

## ".

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### Lignite and subbiturninous coals produce ash that plugs and blinds catalysts 

### (25-28). The problems currently experienced with SCR catalysts include the formatiou ofsulfate- and phosphnte-based blinding materials on the surfnce ofcatalysts and the c,arrying ofdeposit fragments, or popcorn nsh, from otherparts ofthe boiler and depositing them on top ofthe SCR catalysts (14)_ The most significantproblem tilat limits the successful applIcation ofSCR catalysts to lignite coal is the formatiou oflow-temperature sodimn--calcium-magnesium sulfates, phosphates, and possibly carbonates that will form au the surfaces ofcatalysts and the carryover ofdeposits that wi1l plug the catalyst openings, resulling iu iucreased pressure drop and decreased efficiency (14-16, 

### 27-28)_ The-degree ofthe ash-related impacts on SCR catalyst performance depends upon the composition ofthe coal, the type offiring systems, flue gas temperature, and catalyst design 

### (15-16, 24, 27-28). 

### In studies (7) the impac15 oftemperalUTB and the presence ofcatalyst on the ability ofash to sulfate were examined. The tests were conducted using a thermogravimetric analyzer (TGA). TGA testing was conducted using a <5-l'-m-size fraction ofash produced from Powder River Basin (PRE) coals and lignites and exposing lhem to vapor-phase sulfurdioxide with and without catalyst at several temperatures. The aim ofthe testing was to determine the potential of the formation ofsulfates to cause particle-to-partlcle bouding that leads to the formation of deposits in the temperature range where SCR catalysts are used. The TGA testing is focused on -determining the reactivity ofllie <5-J.lm ashproduced from selected PRB and blends 10 sulfur

dioxide mid gas-phase phosphorus species ns a function oftemperature_ Testing was conducted ';,to 

### determine the weight gain with fiue gas containing armnonia. The impact temperature on the

weight gain due 

### to the formation ofsulfates for a PRE blend is shown in Figure 8. The rates of "sulfation were found to increase 

### willi increased temperature_ The results show an increase in the

weig,ht gains when llllllllonia and phosphorus were added. Ground catalyst was mixed with PRB and placed in the TGA. Increases in weight gain were observed when catalyst was added as compared to baseline cases for 

### 100% PRB, as shown in Figures 8 and 9, respectively. The presence ofcatalyst enhauces the formation ofsulfates_ Full-Scale SlipslreamTesting More recently (8), the behavior ofash and mercury in flue 

### gas produced from the combustion oflignite and subbituminous COllis 

### from the United States ofAmerica in selective catalytic reduction (SCR) systems for nitrogen oxide removal has been examined. Typically, these coals conlaln ash-forming components lh.at 

### consist ofinorganic elements (sodiwn, magnesium, calcium, and potassium) associated with the organic matrix and minernl grains (quartz, clays, carbonates, sulfates, and sulfides), Upon combustion, these coals produce ash tbat has an abundance ofalknli and allmline-eartb-rich oxide particles «5 !1m) that are carried into the backpasses ofthe comhustion system and react 

### with .flue gas to form sulfates and possibly carbonates. The forms ofmercury in the fiue gasproduced from the lignite and subbituminous coals are dominated by the elemental form. Slipstream testingwas conducted at two suhbituminous-fired power plants and one lignite-fired power plant to determine the impacts of ash on SCR plugging, blinding, and mercury oxidation.

### The SCR slipstream system consists oftwo pllmary componenls: the conlrol room and the SCRreaclor. The reactor section consists ofa cotalyst section, [lJl ammonia injection system, [lfjd sampling ports for NO, al the inlet and exit ofthe calalyst section. The conlrol room houses a computer system th:Illogs dala and eonlrols the gas now rales, tempcratures, pressure drop ncross Ihe calalyst, and soolblowing cycics_ The computer

### is progrmnmed to maintain constant temperature oftlIe catalyst, gas Ilow rates, sooLblowing cycles, and ammonia iojeelioll_ The computer is equipped with a mouem that allows for downloading ofdata and modilication ofthe opcration ofthe reactor from a remote computer located allhe EERCl'lue gas is isokinetIealIy extmeled from the convective pass oflhe boilerupslream ofthe air hcater_ The temperatllre is t)1lically about 790"F. Thc nue gases pass through a 4-inch pipe equipped with sampling, Lhennocouple, and pressure ports. Ammoniais injected into the piping upstream ofthe reacLor section. The reactor consists ofa sleeI housing that is approximately 8.5 inches squore and 8 feet long. The reaclor section has three components, including allow straightener, a pulse sectIon Or sootblower, and a catalysttest section. A mctnl honeycomb is used as a flow straightcnerupstream ofthe catalyst section and is about 6 Inches long. A purge scction was instn]]ed ahead ofthe catalySL test section to removc accumulated dust and deposits. The catalyst test section is locaLed downstre3lll ofthe pnrge seclion_ The enlire catalyst section is insulated and equipped with strip heaters for temperature conlroL The catalyst test section is 3.28 ft (1 m) in length and houscs threc catalyst seclions. Thennocouple and pressure taps are located inthc purge sections for measnrements before and after cach section_ The induced-draftfan is used to extract approximately 400 acfin (200 sc.fm) offine gas from the convective pass ofthe utilIty boiler to achi",ve an approach velocity of5.2 mls ',-'j' 

### (17.0 

### ltIs). The gas velocity is similarto that found in full-scale applications. The tolal gas flow through the rcactor represents a thennalload ofapproximately 300 kW. The range ofoperdting conditions for the reactor is listed below: X Gas temperatllre: _700"_800°F X Gas flow rate: 400-500 acfm X Approach velocity range: 5.0-5.5 mlscc X Ammonia injection rate: 0.5:1 with NO, level X Tempering air for fan:

- 50-200 scfm X Calalysl dP, 0.5-1.0 inches water column X Fan sizcd for up to 30 inches water coluum The catalyst installed at the Baldwin aud Coyote Stations was the HaldorTopsoe catalyst. Topsoc's DNX-series ofcalalysts comprises SCRDENOX catalysts tailored to suit a comprehensive rimge ofproccss rcquirements_ ONX-series catalysts arc based on a corrugated, fibcr-reinforced titanIum dioxide (TiO:!) carrierimpregnated wilh the active componenlS vanadium pentoxide (VI05) and tungsten trioxide (WO,). The catalysl is shaped to a monolithic slructure with a large nllmber ofparallel channels. The lJIlique catalyst design provides a highly porous stnlctmc with a large surface area and an enstliug large numher ofae/ive silcs_ The pilch ofthe catalystwas approximately 6 Illln_

### The catalyst installed at the Columbia Station was a BabcockHitachi plate-type catalyst. This catalyst is a Ti02 -based plate catalyst, developed and manufactured byHitachi. The pitch of the catalyst was approximately 10rnm. The coals produced ash that had significant accumulations ofash on the catalyst on both macroscopic and microscopic levels. On a macroscopic level, there were significant observable accumulations that plugged the entrance as well as the exit ofthe catalyst sections. On a microscopic level, the ash materials filled pores in thc catalyst and, in many cases, completely masked thepores within 4 months ofoperation. The deposits on the surfaces and within the pores oflhe catalystconsisted ofmainly alkali and alkaline-earth element-nch phases that have been sulfated- The resullE ofthis testing found that the <5-flill 

### ash rich in alkali Md alkaline-earth elements is captured on the surface and within the catalyst pores. These materials react with 

### S02/S0J 

### in the flue gas, resultingin Ihe formation ofa continuous phase that blinds the catalyst. The ability ofelemental mercury to be oxidized across the SCR catalyst was investigated at a North Dakota lignite-fired plant. These rcsults showed no oxidation ofmercury across the SCR catalyst. The reactor was installed at lheBaldwin Station and operated for a 6-month timeperiod on the HaJdor Topsoe catalyst. The information obtained from testing included pressure drop, _sootblowing cycles, andreactor temperntures. Figure LO show lhe pressure drop across the catalyst test periods from 0 to 2 months. During lhe fiISt two monibs ofoperntion, the pressure was about 0.5 inches ofwater; at the end ohwo months, the pressure drop was about 0.8 inches ofwater, indicating plugging had occurred. The air was pulsed a minimum ofevery 8 hours in an attempt to maintain cleanliness. The reactorwllS monitored on adaily basis, and adjustmenlE 

### in pulsing cycles were made 

### in orderto minimize deposit accumulation. However, for the first two months, the pressure drop steadily increased. There are several periods where the unit was taken off-line; during those times, the temperature oflhe catalyst was maintained. At 2-month intervals, a section ofcatalyst was removed and replaced with a new one. ForMonths 2 through 4, the pressure drop was highly variable initially butwas ahout 0.8 inches ofwater. From Months 4 lhrough 6, the pressure drop was maintained between 0.6 and 0.8 inches ofwater. This is due to thc installation ofa fresh catalyst section and leaving two thirds ofllie catalysts in place that were partially plugged. The gas velocity in the single section ofnew, clean catalyst was high because ofchanneling, and the resull ofthe high gas 

### flow was less deposition and accumulation. Gas 

### velocity has a significantimpact on the potential for deposits to form. However, at high gas velocity, low NO, conversion is likely. The reactor was installed at the Columbia Stalion and operated for a 6-month period of time with the BabcockHitachi calalysL The infonnation obtained from the testing included pressure drop infonnation, sootblowing cycles, and reactor temperature. Figure 11 shows lhe test periods from 0to 2 months. The pressure drop across the SCR upon installation was ahout 0.4 inches ofwater and increased to an average ofabout 0.5 inches ofwater, butranged from less than 0.4 to greater lhan 0.8 inches ofwater. The pressure drop for Months 2 to 4 iucreased from about 0.5 10 0.7 inches ofwaterbecause ofaccumulation ofash. Alter cleaning thereactor and replacing one catalyst scclion, the pressure drop was about 0.3 butincreased to over

### 0.6 inches o[water IIp to about4100 hOlIrS_ There was.1Il outage at the plant, aud aggressive pulsing o[ the reactor was conduded; the pressure drop w>ls 

### broughtback dOWllto 0.3 but rapidly increased to 

### over 0.5 inches ofwater within 500 hours. The snme reador that was installed allhe Baldwin Stalion was moved and installed at the COyOle Statiou. 

### In addilion, the same HaldorTopsoe catalyst lype WfiS used iu the reador_ The reador was operated for a 6-month period oftime, Figure 12 shows the test periods from 0 to 2 months. As this papcris being prepared, the reactor is still operating on-site_ The pressure drop across the catalyst lIpOn installation WfiS about 0.4 inches ofwaleL After only 750 hours, the pressure drop was 1.5 inches ofwater, indicating significantplugging and blinding. Vcry aggressive air pulsing was conducted, with lillle success in removing the deposits_ The pressure drop for the catalyst was over two times greater than the pressure drop observed [or the Baldwin Station utilizing the Same reactor and same catalyst. At about 1700 hOlies, the reador was cleancd, and a sedion ofcatalyst was removed for characterization. The pressure drop after cleaning was aboul 0.8 to 1.0 inches ofwatcr. The pressure drop did nol increase as mpidly because ofthe higher velocities through the clean section ofthe catalyst. The tops ofthc catalysts Were photographed during inspection and sampling ofthe catalyst sections_ Figure 13 shows the ash materials that IIccumulated on the catalystinlel afler 2 months ofoperation_ The most significant accumulation was noted for the Coyote Stalion, followed by Columbia and Baldwin. The Coyote Station had SOme largerpieces ofllsh deposit matcrial on the surface as well as plugging,ofthe catalyst passages_The Baldwin Station showed SOme obvious deposition along the walls ofthe reactor and some accumulation on the inlet scctions_ The Columbia Station showed more significanl accumulation and plngging than the llaldwin Statiou_ After4 months, the tops ofthe catalysts were photographed during inspection aud sampling oflhe catalyst scctions, as shown in Figure l4_ The most significant accumulation was noted for the Coyote Station and SOme accumulation for the Baldwin Station_

SCR Ash Deposit Characterization The characteristics ofthe ash malerials that collected on the catalyst surfaecs and pores were charaderi7.edby SEM and x-my microanalysis and, in selected cases, XRD WIlS used to -,- determine (he crysmlline phases present. The catalysts were sampled afler 2, 4, and 6monlhs_ The sections were sampled, and approximately 2.5,cm squares were mounted [or SEM analysis 011 double-stick tape and in epoxy resin. The double-stick tape samples allowed for characterization ofthe external morphology ofthe particles and catalySl surface_ 111e samples mounted in resin were cross-sectioned and polished, which allowed for more detailcd and quantitative analysis ofthe bondirrg materials 'llld materials that accumnlated irr the pores ofthe catalyst. Delailedinfoml'llion on all the samples can be found elsewhere (add FPT reference). Examples oftwo deposit and catalyst analysis are presented here. The 6-morrth sample [rom the Baldwin Station showed extensive sllifation ofthe alkalincC<lrlh elements presenl in the deposits. Figures 15a and l5b show regions ofthe catalyst where all the pores were blocked and a minimal amount ofdeposit on the surface ofthe catalyst. Figure';>' 

### I

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### 15c shows a higher-magnification view oflhe deposilthat is filling the catalyslpore. The deposil consists ofparticles offIy ash bonded logelherby amatrix ofcalcium- and sulfur-rich malerial, lIkely in Ihe fonn ofcalcium sulfate. The chemical compositions ofselected points that indicate Ihepresence ofhigh levels ofcalcium and sulfur are listed in Table 3. There is much more extensive bonding ofthematerials withthe sulfute matrix as compared to the 2-montlt sample. 

### In addition, there are someregions ofhigh levels ofcalcium, aluminum, and sulfurpresent. The calcium alumimun materials are likely derived from the calcium aluminum phosphale minerals found in Ihe coal fired allhis plant. The 4-month sample from the Coyote Slation showed particles adhering to the surface and filling pores in the call1lysl. Figure 16 shows Ihe 4-monlh sample from !be Coyote Station. The catalyst showed partieles adhering lo the surface and complelely filling and masking the pores in the calalyst. The exlernal morphology ofthe catalysl surface shows the masking ofthe catalysl surface. Chemical compositions ofselected poinls are shown in Table 4, The 4-monlh sample shows more sulfalion than the two months ofexposure samples. Figures 16b and l6c shows a higher"magnificalionview oflhe deposit that is filling the calalystpore. The deposil consIsts of particles offly ash bonded togclher by a malrix ofsodium-, calcium-, and sulfur-rich material, likely in the fonn ofcalcium sulfalc. Significant sodiumwas fOWld in the deposits, as shown in Table 4. The sample shows significanl evidence ofsulfation after 4 months ofexposure lllld was much more pronounced lhan Ihe samples [or Ihe Baldwin and Columbia Stations that are fired on PRRc'oais. The presence ofsodium enhances Ihebonding and sulfation o[lhe particles to form a stronglybonded matrix (22).

SCR DepositFormation Mechanisms .The mechanism forthe formation ofdcposils that blind SCR calalysls involves Ihe lnmsport ofvery SInali particles rieh in alkali and alkaline-earth elements, the surface ofthe catalysl, and reactions wilh SO,/SOJ 10 

### form sulfates. The formation ofS0:I from SO. is catalyzedby [he SCR; Ihis, in turn, 

### increases the reaclion rate ofSO] to form sulfales_ 

### In some cases, the alkali and alkaline-earth elements will also reacl with Co, 10 

### form carbonales. XRD analysis identified**caSo~** 

### as a majorphase and Ca,Mg(SiO.), and CaC01 as minor phases. lignite and subbituminous coals contaIn high levels oforganically associated alkali and alkaline-earth elements including sodium, magnesium, calcium, and potassium, in addilion 10 

### mineral phases. The primaryminerals presentin Ihese coals include quartz, claymInerals, carbonates, sulfates, sulfides, and phosphorus-conlaining minerals (6). During combustion, the inorganic components 

### in the coal arcpartitioned into various size fraclions based on the type ofinorganic componenl, Iheir associalion In the coal, and combustion system design and operating condilions. Significantresearch has been conducted on ash formalion mechanisms and relationships to impacts on powerplantperformance 

### (1--6, 9-13, 19- 21,29). During combustion, the inorganic componen1s associated with western subbituminous and lignite coal typically are distributed inlo various size [raclions orash. The smaller size fraclions ofash arc dominated by partially sulfaled alkali and alkaline-earth e1ements_ These ash particles are largely derived from!bc organically associated calioIlS in the coal. The larger size



# "

### fraction has higher levels o[alumimun and silicon derived from the mineral [mclion ofthe ashfonning component ofthe coaL Entmined ash was extHlctcd from the Columbia Station at the point ofthe inlelto the SCRreaclor and was aerodynamically classified and analyzed. The composilion ofthe size fractions was compared to the chemical composition of !he ash <.leposited on and in thc catalyst.,**a~ ~hown**  

### in Figure 17. 

### The comparison shows lhal the composition ofthe particle caplured in the SCR catalysl is very similar to the <5-'.lln size [metion. The deposited material shows significantly more sulfation lhanthe entwined-ash size fraetioIl, indicating that the sulfation process occurs after the particles arc deposited in the cnmlysL The mechanism ofSCR calalysl blinding when firing lignite or snbbituminous coals is shown in Figure 18 (30). The requirements for the formation ofdeposits that blind SCR catalyst include firing a coal that produces significantlevels of<5-!-Im-sized particles. The particles are trnnsportcd. into the pores o[(he catalyst and subsequenlly react with SOj lo form sulfates. The snlfate [onns a matrix that**hond~** 

### olher ash**particle~.** 

### The SCR catalyzes the formalion ofS03 and thereby increases the ,dte ofsuIfation (24, 25). The sulfation ofCaO increases the molar volume, resulting in the filling ofthe pore. For coals thal have high sodium contents, formation ofJow-melling-pointphases such as pyrosulfates is possible (31). 

### Pyrosulfatc materials Can 

### melt at tempeIQtures as low as 535"1' 

### in coal-fIred power systems.

..;. 

# '" FR , , 

### , 

# , Weight Gain lor LSUS-PRB Blend

/80Q"F 

# I 

# r 700"F 600°F 

# / /' 

# V 0.015 c 

# '. "5, 0,010 

### en 0,020 

### E



## o

## o 0.025 0.030

0.005



### Time, min 

### Figure 8. Weight changes for PRB-blend coal ash exposed to flue gases and ammonia allhree temperatures.



# "

# = OM 

### Baseline and CatalystTests lor PRB
PRB 

### + Catalyst**P~** 

### Baseline



### , 

# / 

# ,**~/** 0.00 0.007 0.008



### gj 0.006 

### rn 

# i 0.005



### c 0.004 

# • (!J J::. 0.003 .Q> 0.002



## oo 

# " Time, min 

# '"
Figure 9. 

### Weight changes for PRB-blend coal ash exposed to nue gases und ammoniawillI and without SCR catalystpresent.



# " 

# " '" 0

# , I 

# ",
c '0 

### u


# - 0.' 

### w 

# • 

# .. 0.' 

### 0 

# '" 0.' 00 0 

## '00 600 BOO 1000 

### Run Time, hr 

## "00 

# ,."

Figure 10. Catalystpressure drop at Baldwin Station at 0 to 

### 2 months ofoperation.

## '2 ,----------------**~"'.~~~""-""** 

## LO-l-------------------_j Q ,------ I O.B1 

### c 

# '----+- U 0.6;**_~** 0.4 

## o

## 02+--:'.-~----.J--~----+_If__j

1500 1000

### o.o-l-------~-----~----""'-_j 

## o Run Time, hr

Figure 11. 

### Catalysl preSSl"" drop at Columbia Station at 0 to 2 months ofopcrotion.


# '.0,-------,------"'1--""\

0

## " Ic 

# ,., TI , .0 

# " ;:; 

# " 0

1000 

## o.o-l--**-----~-.JL-.L-_j** 

## o Run 

## lime, hr Figure 12. Cal.lystpressure drop JT CoyNe Slalion al 0 10 2 month, ofoperntion.

### Bllidwin Stlltion after 2 months

Coyote Station after2 montbs

Columbia Station after 2 months

Figure 13. Pictures ofcatalyst inlel after about 2 months oftesting at each plant.

# ,
, 

## .' " 

# :1

r: 

### II9f

# Il' lOOl**."----------~----'** -i;



# " ,

# ., Baldwin Station ane.. 4 months

Coyote Station after 4 months

.·'gure l4. PiclIl'c., uf-comly,( hold aller "bollt4 monlhs of.'posu,e La !lue gas "od parlieDI"",.·'.-. 

### A



# •

c

Figure 15. SEM images ofash collccte<l on calalyst surface at lhe Baldwin Station after 6 monlhs ofexposure. A) and B) low-magnification images ofash deposit on ealalyst surfaceamI C) high-magnification image ofpolished cross section showing particles in a matrix of calcium- and sulfur-rich materials. Table 3.**Ch~mic"l** Composition ofSelecled Poiol. and Areas in Figure 15 Cllemical composilion (norrmli?ed wl% equivalCTll oxide) Oxide POinl I Point 2 Poinl3 Point4 Poiul5 Poinl6 

### 1.1.1 

# "' '.0 

# " 03 0' 

# ,., Na,O U 

# " 

# •., 0.' 

# ,. " M,O 14.8 16.0 15.6 15.5 H.7 

# ., AI,O, B 

# " 19.9 57.7 

# ,., 47.3 SiO, 

# " U 

### 0' 

## o. u 0.0 P,O, 30.7 20A 17.7 

### 0.' 29.0 

# "' '0, 

# ., "" " 0.' 

# "' 0.' K,O 28.8 28.7 28.1 22.5 34.9 28A 

# ""0 '.0 U 

# " '0 U U TiO, 11.4 12.9 

# . , 00 

# ,

# . " Fo,O, U

" 

# " '.0 0.' 

## '0 ,,0**T~'** 

### W. W. 

# '"" wo 

# '"" '"" Oxide Poinl7 Poja! 8 Poinl9 Poinl 10 Point 11 Poinl 12 

### ',;' 

### 1.1.2 u OA 

## "0 

# " U
" N.,O 

# ,. 

# ., " 5.0 H 

# •.,**~,** MgO 

### .0 

# ,., '" 19.2 10.8 

### 3.g 111,0, 

# 'A 18.4 18.5 31.0 17.9 16.7 SiO, U 

# ., '" 0.' U 

# " " P,O, 37.9 U 5.3 

### 0.' 

# '" 13.9 

# '0, 

# ., '.0 0.' 

# "., 0.' 

## O. K,O 3\.4 52,G 49.0 28.9 30.6 45.4 

### 0.0 

# " 

# •• " " 

# ,

# .• U TiO, H 

### n 

# " " 

# ., '0 Fe,O, 

# •• ,

# .. 3.5 

# ,., '" B 

### ',0

Total 

### WO W" 

## wo 

# '"" w. W.

### A

B



# c

Figure 16. SEM imngcs 

### orash collected on catalyst surface at the Coyote Station after 4 months ofexposlire. A) 

### low-magnific3iioll image ofash deposit on catalyst surface, B) low-

### magnification image ofpolished cross section showing particles in a matrix ofcalcium- and sulfur-rich materials. and C) higher-magnification image ofbonding. 1.1.2.1 Table 4. Chemical Composition ofSelected Polnls and Areas in Figure 16

TOlai 

## '00 

## wo '00 '00 W, Oxide Poinl6 Point7 Point 8 Point 9 Poinl 10 

### 1.1.4 

# i0 

# ", 

# '" lOA 

# ,. <A N.20 U 

# ,. U 

### '0 U M,O 

# " 

# " 

# ,., ,

# .• 10.6**i~** Al,O, U 18.2 10.5 

# " 28.9 SiO, 

### 0.' 

# ,. 0.0 0.' 

### 0.' 

## r,o, 41.8 28.4 44.9 44.5 23.4 

# '0, n 

# " u 

# " 3.8 K,O 245 <A 22.5 12.8 

# " C,O 

### 0.' 

# " U 

# " 

# " TiO, 

# " 

# ., ,. •• 13_2 Fe,O) 

# " m 0' 

# ,. " "0

Total 

## wo '00 

## wo

## o EEM 

### f2!<lpm 

# rn 1 104.6pm 4.6 10 

### 22pm 

# 1--------- m>22pm 

## EE Cala.lyst Ash

Figure 17. Comparison ofentrainedash and dcposi,ed ash oncatalyst for Columbia Station.

### Particles

- Silicates**~.** Small Particles

# tf---...... •• Na, Mg. Ca, K**~.**

Pore SUIJur Oxides 

### ,,--Carbon Dioxide
No Delerloration Yet (NHJ and NO. can react in mlcropore on catalyst sUrface)

__ Reactions with SO:! and CO2 

# >- PaI1iclos

_ Sille'll., and other RyAsh P""iclos

_____ Motel, Moleri" ., Parliolly**Sulf~\.d** AlKali and Alk.line.Eanh Oxldos 14% Expansion ,---Malrix Malorial
- Fully $ul!al.d Alkel; and Alkallne_Ea<1l.O:<id""

'--**P.~loles** - SiIIcal"s and**Olh~r** Ay Ash Feniclos



### DeterioratIon (NH, and NO, cannot react in micropore on catalyst sUrface)



### Figure 18. Mechanism 

### ofSeR catalystblinding via the formation ofsulfates and carbonates (modified after Prilch:lrd and others [30])_ 

### Low-Temperalure Pyrosulfates The presence ofsodium sulfate 

### in the flue gas exiting n scrubber will cause problems to low-dust lind tail-end devices such as sc1edive catalytic reduclion (SCR) syslcms for

### NO, reduction. There are two problems associaled willi the line particulate rich in sodium sulfat<} On downslream devices. These include accumulalion offine particles On the SCR that, when soolblown, will cause opacity problems, and**lh~l** 

### the.fine partIcles on lhe SCR will fonn pyrosuJfatcs such as 

### (KLsNa o.s)S,Oj thal have meJtingpoinls as low as 535 Q

### F (31) lhal wiD blind lhe calalyst. The presence ofthese compounds in low-temperature corrosion deposit<; is well known (32). In addition, lhe presence of

### SO) enhances lhe formation oflhe low-mellingpoint pyrosulfales (31). The sodium sulfale malerials will cause opacily and SCR catalyst -:-,

# " w 

# " w



## " 

# " blindingproblems thai limit the feasibility ofthe low-dust or tail-end SCRtechnology for use wIlli high-sodium lignite coals. The sodium sulfate materials will be transported to the catalyst surfaces by diffusion, electrophoresis, and, possibly, inertial impaction. The particles are held in placebyweak electrostatic and van der Waals forces. Once accumulation takes place, the sodium sulfate particles will react with flue gas components, resulting 

### in the formation ofpyrosulfates_ The formation ofpyrosulfates involves the following processes (31):
1. Formation ofsulfates such as**Na,SO~** 

### lind KlS04 2. Conversion 0[S02 to SO, in thebulk gas phase- catalytically active surface such as an SCR catalyst

- SOl 

## + O2----t 

### Sal 3. Pyrosulfate formation

- Na,S04 

## + SO) ----t 

### Naz S2o, The melling points ofselecledpyrosulfatc phases are shown 

### in Table 5.

Table 5. Mellin Points ofSelected P rm;ulfale Comnounds Componnd Temperature, QC Teropet:ature, OF 

### K:J'e(S04)l**61~** 

### 1144 KlAl(S04)l 

## 654 1209 

### KFe(S04)1 

## 694 1281**Na]Fe(S04)~** 

## 624 1155**Na,Al(SO.)~** 

## 646 1195 

### NaFe(SO,), 

## 690 1274 

### Na,S207 

## 401 754 K1S,O, 

## 300 572**(Kl.~Nao.5)S,O,** 

## 279 535
Melting points for pyrosulfates between 535" and 770"F 

### have been reported in the literature. Much ofthe pas! workhas focused on [he formation oftbese phases on tube surfaces_ These species contribute to the corrosion ofheat-transfer surfaces in coal-firedpowerplants. The exaclmeltingpoint depends on the relative lIIIlounts ofsodium and/orpotassium_ There is significant evidence for the formation ofsodium-rich fine particulate in full-scale powerplards when firing high-sodium-containing coals. Forexample, l'vUnnesola Power's Boswell Energy Station found that when it fired high-sodilUll, lower-ash subbituminous coal, it experienced increases in opacity. Hurley and Katrinak (33) conducted a field-testing project on Unit No.4, a pulverized coal-fired boilerequipped wilh an electrostatic precipitator and a wet scrubber, 

### to beUerundersland the reasons for the opacity problems. During the field testing, sampling ofthe coals, flue gases, and scrubbermaterials was comlucLed_ The particulate 

### in flue gases downstrellIIl ofthe scmbberwas aerodyr13mically classified using an impactor and

### multicyclOTIe. The sizcd fractions were analyzed to determine the composition ofthc submicronsized fmction.

The resulls ofthe study**indic~led** 

### that theparticulate collected**downstre~m** 

### ofthe scrubber was**co~l-rejated** 

### and caused by the high sodium content ofOne ofthe coals. Vapor-phase sodium condenses in the convective pass to Jorm fine sodium sulfate particles or otherNa species that laterreact with ash particlcs_ Pure**NalSO~** 

### particles are too**sm~lI** 

### to be removed by scrubbing_
CONCLUSION: SCRIS NOT FEASIBLE FOR NOx REDUCTION AT j\ULTON R 

### YOUNG The ash deposition behavior ofthe lignites from North**D~kota** 

### is the most complex and severe ofany coals in the world,**~nd** 

### installation ofcatalysts for NO, reduction is going to be**jmpos~ible** 

### because oJthe fonnation 

### ofsodium calcium sul£1tcs in the pores ofthe catalyst Following is a list ofthe key roadblocks associated with lignites which have not bcen overcome >lIld, in our opinion, make the installation ofSCR catalyst at the MRY planttechnically infeasible for NO, control. High 

### alkali and nlkaline-earth clements present in 

### the coal fired**~t** 

### the MRY plant form sulfates l1k'ltblind the catalyst. Cyclone-fIring partitions the ash during combustion. As aresult the Icvelot" sodium and calcium in the fiy ash is enhanced and will increase the SCR catalyst blinding. Su]Jil.te reactions increase with increasing tcmperalure, and thc suggested temperature ofinstallalion al the MRY fncilily is higher than typical installations; therefore, salfation problellls are enhanced. Sulfate fonnation is also enhancedby the presence ofan SCR catalyst; this accelerates the sulfation**re~ctions,** 

### C<lll.>ing blinding ofthe ealalyst The high levels ofso(\iwn in thc coals combined with calciumproduces lowmelting-point eutectic compounds that will mclt On the surface. Sulfates form on the surfaces ofcatalysts firing PRB coals. Lignites will be several orders ofmagnitude worse because

# orthe higher levels ofsodiulll.

• The ash componcnts to impact SCRperfOmlaHCe in Japan nod Europe (14--16) Include alkali and nlkaline-earth elements that result in sul£1te formation. The total calcium content and the sum oflhe calcinm, magnesium, potassium, and sodiumprovide an indication ofthe problems that occur. For the coals fired at the:MRY powerplant, lhe CaO content ranges from 6.8% ··19.99%, mJd the sum oflhe alkali and**alkaline-e~r1h** 

### elements range from 9.33%-29.87% ofthe ash. The levels ofcalciumin CenterIiguite arc 2 to 4 limes higher than the problematic coals in Japan and Europe_

• The fmding or wolk conducted in Germany nnd Japan were confirmedby recenl SCR catalyst sIipslreom testing that showed significant evidence ofsodInm aod calcium-

### rich sulfate formation lhat fill and plug the catalyst atboth lignite (North Dakota)- and subbituminous-coal-iiredpowerplants. The results oflJJis recent testing showed lJJat thepresence ofsodium significantly enhanced the foonation ofbornling ofparticles and more rapid sulfation, filling ofpores, and rapid increase 

### in pressure drop across the catalyst. Deposit carryover, orpopcom ash, plugging the top ofthe SCR catalyst with deposit fragments, is a significantproblem because ofthe extremely high deposition potential ofthe coal. The foonation ofdeposits in various parts ofthe boilerrequires continuous sootblowing. The deposit fragments are likely going to be carried with the bulk gas flow to the SCR catalyst, resulting in plugging. The variability ofthe lignite is a problem ofunique cOncern at "MRY. The deposition potentIal ofthe coal is always changing rapidly, resulling in rapid growth and foonation ofdeposits io various sections ofthe boiler. Aggressive sootblowing ofall fireside surfaces is already required to maintain full-load operalion_ The soolblowing of upstream heat exchange equipment will cause deposit fragments to be carriedback to the SCR catalyst, and during sootblowing ofthe SCR catalyst, the entrairunent of deposit fragments along with the sootblowing media will result in significanterosion of the catalyst surfaces. The ash-related impacts ofthe lignites from North Dakota are the most complex and severe ofany coals in the world, and installation oftail-end SCR systems for

### NO, reduction will not be possible. Thekey problems associated with lignites that have notbeen overcome and, in our opinion, make tho installation oftaj]-end SCR systems at the"MRY plant technically infeasible

. for

### NO, conLIol at MRY's Units 1 and 2 are listedbelow:
X High-sodium lignite coal from the CenterMine Hagel A and B seam coal produces extreme levels ofhoillogeneously condensed sodium sulfate that pass through the wet scrubber_ 

### In addition, the cyclone-firing system captures much ofthe ash as slag, resulting in a decrease in ash that is available for providing condensation sitcs for vaporphase sodium compounds upon gas cooling. This results in an increased homogeneous condensation ofsodium sulfate. X These 5mall particles pass through a wet scrubber and will accumulate on surfaces oftnilend SCR systems, The accumulated materials cannot feasibly be resolved through conventional sootblowing and cleaning technologies to remove the particulate.
X Recent testing with subbituminous and lignitic coals imlicated a significantlyhigher level ofpore filling and plugging in the catalyst exposed to lignite ash as compare 10 subbituminous coal ash. The catalystpores as well as the catalyst surface in the lignite tcsts were completely coated with a sodium calcium sulfatc matcrial, while only pore filling was found in thc subbituminous coal testing. The pressure drop across the catalyst exhibited for lignite was 4 to 

### 5 times greaterthan that found for a catalystexposed to 

### subbitnminous coal ash. The plugging occurred over a 

### 1000hour lest period.

### The formation ofliqui<1 pyrosulfate materials allemperalures ns low ns 535°F 

### from sodium sulfate materials Occu,s in coal-firedpower systems and is well documented_ Pyrosulfates will form and CaUSe blinding ofmil-end SCR devices. Tn addition, SCR systems catalyze the formation oISO] from SOl. The presence orSO) significantly enhances the fonnation ofthe pyrosulfates at MRY 

### to an extreme level that cannotbe 

### deall with effeclively using cleaning technologies thal exist today_

REFERENCES 1. 

### Mehta, A.; Benson, S., 

### Eds. Effects of Coal Quality on PowerPlanlManagement: Ash Problems, Managemenl. andSolutions; 

### UniLed Engineering Foundations Inc.: New York and EPRl: Palo Alto, CA: 2001. 2_ Schobert, RR 

### [.ignites of North America; Coal Science ond Technology 23; 

### Elsevier: New York, 1995. 

### 3_ Baxter, L.; 

### DeSolJar, R., 

### Eds. Applications of Advanced Technology to A.,lJ-RelatedProblem.'· In Boilers,- 

### Plenum Press: N",,, York, 1996. 4. Couch, G_ 

### Underswndlng SlaggingandFouling DuringpfCombuslion; lEA 

### Coal Research Report",1994. 5. Williamson, J.; 

### Wigley, 

### F., Eds. 

### 1Mimpaci of Ash Deposition on CoalFiredPlants: Proceedings of the EngineeringFOl/ndation Conftrence; 

### Taylor & 

### Francis: London, 1994. 6_ 

### Benson, S.A.; Jones, M.L.; 

### Harb, J.N. Ash Fomlallon and Deposition-Chapter4. In Fundamemals of Coal Combustionfor Clean andEfficienl Use: 

### Smool, 

### L.D., Ed.; Elsevier: Amsterdam, London, New York, Tokyo, 1993; pp 

### 299-373. 7. 

### Benson, SA., Ed. inorganic Transformations andAsh Deposition During Comlmslioll. 

### Ameriean Society ofMechanical Engineers for the Engineering Foundation: 

### New York, 1992. 8. Bryen;, R-W_; Vorres, K.S., Eds. Proceedings of/heEllgineeringFoundation Conference On Mil/era!Malter andAsh Depositionfrom Coal, 

### Santa Barbara, CA, Feb 22-26, 1988; United Engineering Trustees Tne", 1990. 9. Raask, E. 

### Erosion Wear In Coal UtilityBailers; 

### Hemisphere: Washington, 1988. 10. Raask, E. 

### Millerolimpurities il! 

### Coal Combu.stioJl; 

### Hemisphere: Washington, 1985. 11. Benson, S.A., Ed_, Ash Chemislry

__ Phase Relationships ill

### Ashes am!Slags, 

### Special Issue of Fl/el Frec,,"".,·. Teclmo!_; 

### EI5evier Science Pnblisbcr:s: AmslenJarn, 1998; Vol. 56, Nos. 1-2, 

### 168 p_

### 12, Laumb, M_; Benson, S_A.; Laumb, J_ Ash Behaviorin Utility Boilers: ADecade ofFuel and Deposit Analyses. Presented allhe United Engineering Foundation Conference on Ash Deposition and Power Production in the 21sl Century, Snowbird, 

### UT, 

## Oct 28

- Nov 2, 2001. 13. Benson., S_A.; Hurley, J.P_; Zygarlieke, C.L; Steadman, E.N.; Erickson, T.A. Predicting Ash Behaviorin Utilily Boilers, 

### Energy.Fuels 1993, 7 

### (6),746-754. 14. Licata, A; Hartenstein, 

### H.D.; Gutberlel, 

### H. Utility Experience wilh SCR in Gennany. 161h Annual Inlernational Pittsburgh Coal Conference, Pittsburgh, PA. Oel 

### 1 I-IS, 1999. 15. Cicbanovicz, J_E.; Broske, D.R. AnAssessmenl ofEuropean Experience with Seleclive Catalytic Rednclion in Germany and Denmark. EPRl-DOE-EPA CombinedUtility Air Pollution Control Symposium: The MEGA Symposium, Atlanta, Georgia, Aug 16-20, 1999. 16. Ciehanovicz, JE; Muzio, LJ_ Twenly-Five Years ofSCR Evolution: Implications for US Applications and Operation. EPRI-DOE--EPA Combined UtilityAir Pollution Control Symposirun: The MEGA Symposium, AWMA, Chicago, 

### IL, Aug 20--23, 2001. 17. Benson, S_A.; Kong, L.; Katrinak, K.; Schumacher, K_ 

### Coal Quality Managemenr System,- Final Report for North Dakota Industrial Commission; Sept 1997_ 18. Katrina!<, 

### K-; Benson, S.A.; Laumb, J.; Schwalbe, R.; Peterson, W. 

### MatchingLignite Characteristics and

### Boiler Operation,- Final Report for North Dakota Industrial Commission; Aug 2000. 19. Saro.lim, AF.; Howard, J.B.; Padia, AS_ The Physical Transformations ofMincrnl Maller in Pulverized Coal Under Simulated Combustion ConditioDs_ 

### Combust, Sci_ Techno/. 1977, 16, 187. 20. Loehden, D_; Walsh, P.M.; Sayre, A.N.; Beer, J.M.; Sarofim, AF. Generalion and Deposition ofFly Ash in lhe Combuslion ofPulverized Coal. 

### J. Inst. Energy 1989, 119-127. 21. Zygarlicke, C_J_; Toman, D.L; Benson, SA Trends 

### in the Evolution ofFly Ash Size During Combuslion 

### Prepr. Pap_-Am. Chem. Soc_, Div. Fuel Chern. 1990,35 (3), 621--636. 22. Benson, S_A.; Fegley, M.M.; Hurley, J.P,; Jones, M.L.; Kalmanovilch, D.P.; Miller, B.G.; Miller, S.F.; Steadman, E.N.; Schobert., H.B-; Weher, BJ.; WeInmann, J.R.; Zobeck, RJ. 

### ProjectSodium: A DetaifedEvaluation of Sodium Effects 

### in. Low Rank Coal Combustion Systems; Final Technical Report; EERC publication, July 1988. 23. Hurley, J.P.; Erickson, T.A.; Benson, SA.; Brobjorg, J,N.; Sleadman, E.N.; Mehta, A.K.; Schmidl, 

# c.B- Asb Deposition at LowTempenltures in Boilers Firing Western U.S. Coals_ Inlernational Joinl Power Generation Conference; Elsevier Science, 1991; pp 1--8,

### 24. Laurnb, J_D_; Benson, S.A Bench- and Pilot-Scale Studies ofSCR Catalyst Blinding_ 

### In Proceeding of PowerProduction in the 21s1 Ceutury: Impacts of Fuel Quality and Operations; United Engineering Foundation: Snowbird, UT, Ocl2001. 25. Crocker, C.R-; Benson, SA.; UlUlllb, J.D. SCR CatalystBlinding Due to Sodium and Cnlciulll Sulfate Formalion, Prepr_ Pllp_-Am. Chen!. Soc

.. 

### Vivo Fuel Chem. 2004 49 (1),169_ 26. Benson, S_A.; Laumb, J.D.; Crocker, C.R- Blinding ofthe SCR Catalysts in Lignite ami Subbitumluous Coal-Fired PowerPlants, Presented at The ClearwaterConference on Coni Utilization & 

### Fuel Systems, CIC<lrwater, FL, April 18-22,2004. 27. Senior, C.L.; Linjewile, T_; Denison, M_; Swensen, 0_; Shino, D.; Boekelie, M_; Baxter, L; Bartholonew, 

## c.; Hecker, W.; GllO, X.; Nackos, A.; Whitty, K.; Eddings, E. SCR Deactivation Mechanisms Related to Alkali and Alkaline Earth ElemenL., 2003 Conference on Selective Catalytic Reduction (SCR) aud Selective Non-Catalytic Reduction (SNCR) for NOxControl, Pittsburgh, PA, Oc129-30, 2003_ 28. Rigby, 

### K.; Johnson, R; Neufort, R-; Gunther, Po; Hums, E.; 

### Klatt, A.; Sigling, R. 

### SCR CatalystDesign Issue:; and Operating Experience: Coals with High Arsenic Coneentmtions and Coals from the PowderRiver Basin, Presen1ed allhe International JointPower Generation Conference, IJPGC2000-15067, July 23-26, 2000_ 29. ASTM MeLhou. D6784-02, "Slandard Tesl Method for Elemental, Oxidized, Particle-Bound and Tolal Mercury 

### in Flue Gas Genemted from Coal-Fired Slalionary Sources (OnLario**;'>~** 

### Hydro Method);' at http://wwlV.astm.org/cgi-biniSoItCart_exeIDATABASE-CART/PAGES/ D6784.htm?E+mystorc_ 30. Pritchard, So; Hellard, D_; Cochran, J_ CatalystDesign Experience for 640 MW Cyclone BoilerFired with 100% PRB Fuel, http://www.cormctech.comftechdataiindex_hLmL 31. Singer, J.P_ Combustion, FossilPowerSyslems, ComblJ.Stion Engineering Ine_: Windsor, CT, 

### 1981. 32. Chemislry oJCoal Utilization, Second Supplemenlary Volume. Elliol, M.A., Ed.; Wiley lntcrseience: New York, 1981. 33. Hurley, J_P.; Katrinak, K.A. Determination ofAsh Fonnalion and Deposition Mechanisms at Minnesota Power Clay Boswcll Station; DOElMC/I

### 0637-3365, July 1992.

### APPENDIXC 

### COST METHODOLOGY CAPITAL COST ESTIMATE DETAILS FORNOx CONTROLS O&M COST ESTIMATE DETAILS FORNOx CONTROLSAPPENDlXCI Co,t Melhodology 

### C.1 METHODOLOGY FOR ESTIMATED COSTS NOllBACfAnaly,is Sludy

i -. The summary economic evaluations ofeach allernative >lrC presented in the cost impact sections oflhe main report. Capilal and O&M cost eslimales for-each allemalive are presented individually. The Levelized Total Annual Cost (LTAC) for all the alternatives for control ofa single pollulanl (i.e. NOx) from a single llIlit is lhenpresenled logelher withUnil Control Costs. The Levelized Total AnnUllI Cosl (LTAC) represents the levelized annual cost ofprocurement, construclion and operalion over a 20 year design life, again in curren! (2006) clallam. As a minimum, the design life for any allernative was taken 1.0 be lhal recommended by '"lne EPA AirPollulion Control Cost Manual", Sixth Edilion, January2002, EPN4521B.Q2-00I'.

The LTAC is alw used lo calculate the ave""ge annual and incremenlal cost elTcctivcness ofeach**~ltemative.** The LTACrepresents an mmual paymenl in current day dollam sufficientto finance ilie project over its enlire life.

In detennining the LTAC a Capiml Recovery Factor and an O&M LevelizationFactor were calculated from lhe project economic condilions and then npplied separately to the estimaledcapital and O&lv:\ costs. The equalion used is shown below.



### LACCINPV "'(

# (:~~~)'

# I)

= 

### CRF
Where, LACC LevelizedAruma! Capital Cost 

### NPV = Net Presenl Value oflhe capital investments required. i discountrate n '" design life in years CRF Capilal Recovery Faclor
Therefore: LACC '" CRF Jl NPV
For lite economic conditions descnoed inTable C.I-I the CaPll::lJ Recovery Factor"",s calculaled lo 

### be 0.08718.



### 1n delermining 

### the levelized annUllI O&M cost the estirrutled annual O&M eosl, the inflalion rale, the discounl TIlte, and the equiprnenllife are rnken inlo accounL The O&M Levelization Factor (OMLF) was calculated as follows.**Sq~.re B~rte**  Eloolric CoopOT.tiva Cl-l Burns & McDonnellNOx BAC[ Analysis Sruuy**Wh~TC.** A LevcIiz"<l Annuul O&M Cost (LAOMC) A] = Total annual Q&M cost in current dollars i, = discounl rale i; inflationrate n design life 

### in ycms Thereforc:**LAOMC~OMLFxA,** APPE1\'DlX Cl Cosl Melhodology

For lhe economic conditions described ill Table C-l-I the Operating and Maintenance Lcvdizalion l'aclOr
was calculated lo be 

### 1.24873.

The Levelized TOlal Annual Cosl, or LTAC is the sum ofthe levelized oapital cost und the l.veli2ed O&M cost. Therefore:

LTAC LACC 

### + LAOMC= (CRF XP) 

### + (OMLF x Aj ) 

### 0.08718 x P 

### + 1.24873 x Aj
The differences bCIwcen ull':rn"lives are also presenled graphically in the lorm ofa plot ofthe annual emissions reduction (tpy) versus Ihe LTAC for cuch alLemative. 

### "fill" form ofplot graphical1y depicls 

### the cost effectiveness 01· Unil Control COSI (in Silon ofpollutIDlt reduction) ofeach alternative relativc lo all ofthe others. TI,e oost effcctiv':m:&< i" also refen."d to as the Unit Control Co.,t and defined as the LTAC divided by the annual emissions reduction (tonlyr). The arcu on lhc plot indiculed bythe various dula poinls repre"ents the cosl effecliveu,,"s envelope for !he alternatives under consideration. A smooth line is drawn on this plot connccling the righlmost poinls (those with the lowest co.,t for a given level of emissions reduction). This line is referred lo as theDominant Control Curve (DCC). The DeC defmes lhe righthand boundary ofLhe envelope encomP'!""ing all oflhe alternalives considered_ The DCC is used as a screening 

### 1001 bcl""''''' considered allemativ,,". Those aHcmalives whose ploltcd posilion is above and/or lo the left oflheDCC nrc not as cost effective as those fonning the line and thus can be eliminated from further analysis ifdesired_

In order to compare various pollu\anl control alternati,-es, lhe Unil Conlrol Cost and the incremental Unil Control Cost ofeach alternative were also calculaled and tabulalCd for comparison purposes. The Unit

Burn' & McDonnell Cl-2 SquareDune Eleclric CooperaliveAPPENDlXCI Capit.l CostEstimales**NO~** BACTAnalysis Study

Control Cost compares control technologies on a basis ofdoll= expended per Ion ofpollutmtreduced ($/ton). This reMionsl1ip is graphically depicted in the DCC chllrl.

To more accurately comparebetween alternatives with different costs and control efficiencies, the incremental cost**effec~venes:s** is also determincd forthosc alternatives on the DCC_ The incremental cost effecli"cuess is dcfincd as the LTAC**of~** given eontrol option minns the LTAC ofan aHCIrultive, divided by the difference between !.he ammal emissions reduction (lpy) oflhe given contT,,1 option and thc alternative being evaluated. The CQrnbination ofthese two economic analyses Canbe used as un argument for lhe elimination ofcontrol technologies with significantly greatermarginal control cos!.'; than 

### the given
case. The equation used for 

### the incremental cost effectiveness is shown below.

Where, 

### fCF (LTAC,-LTAC,) 

### (AE, AE,)

ICF = Incremenlal cost effectiveness ($Iincremental ton rem"ved) LTAC, = Levelizcd Total Annual Cost ofcontrol alternativeNo_ I ($/yr) LTAC,= LeveJized Tolal Annual Cost ofcontrol alternativeNo.2 ($Iyr) AEj Control "ption No_ I Annual Emissions Reduction (tonlyr) 

## M= Control**op~on** No_ 2 Annual Emissions Reduction (tonlyr) (The higher cost, more effective control oplion is subscript I in this equation_)

The economic analysespIcsented in lhis reportnot only includethe esLimatedcapital and O&M COSls for cueh allemative, but also 

### the LTAC for economic comparison ofthe various alternatives. 

### Tn addition, the UnitControl Cosl or cost effectiven= is presenled for each alternative. Finally, a comparison between alternatives, in the fonn ofLIIe murginul cost effectiveness, is presented in both numerical and grn.phical form. Thus a comprehensive comparison ofLIIe economic impacts ofeach aHcmalive, as well as the differences in cconomic impaetbetween alternatives is clearly presented_**s~u:rre** Bulle Eleotric Coope<alivo CI-3 Bums & MoD"nncllNOxDACT Analysi> Study


### Table C.1-1 - Economic Faclors(1),(2)

TOlal Possible Operaling Hours perYear Amurtization Life, Yea" Cost ofMoney PropenyTaxes,**Insuranc~,** % Conversion Tax (in lieu ofproporty tax) Amortizalion Rate fm APC Capilal Cosls Intere,l During Construolioo (IDC) DisoountRate (used to CaJeUloleNPV) Conslrue!ion Co,t Escalalion Non_Fuel 0&]1/\ Es",,]ation Fud (coal and natural gas) Escalation Auxiliary Electric Power COSI, ${II.{W-hr Uroa Cosl, ($l1on de1iveTed, 50% aquem" solution) Na[ural G"" (SlmrnBtu) (1) • All financial pere<olllges ao,1 "nil**""~iliary** eke"" power 00" were**pro\';~e,j** loy MPC- (2)

_All 00'," are in 2006 dull"" IInles< noted oUlerwi"". APPENDIX Cl CoslMelhodology

8,760



# '" <% 

### NA NA 6% 6% 6% 

# ", 2.5% 2_5% $35.00 S)80.00

$7.98

Burns&McDonneJl Cl-4 Square**B~tle** Electric OJopef31ivoAPPENDIXC2 Capi",) CostEsliTllllle, NOx BACfAnalysis Study



## C.2 NOx CONTROLS· CAPITAL COST ESTIMATES The capital costs 10 implement the various NOx eontrolledmoJogies were largely estimaled from lll1it outpul capillll cost factors ($IkW) published in ledmical papers discussing lhose control technologies. 

### In lhe cases ofSNCR and 

### FLGR., preliminary vendor budgetary cost information was obtained and used in plaoe of, or to adjust, the published unit output oost factors. These oost e1Ilimales 

### were considered 10 

### be study grade, which is 

### + or- 

### 30% accuracy, or

### bcUcr.

The limitations ofthese ""pHa] cost eSlimales developed from lll1it capital cosl fuctors multipliedby unil output"",:

• Scope basis Ill1certainty

- inability 10 precisely delermine whatscope ofsupply, inclucliug such lhings as baJance-of-plant (BOP) systems and equipment improvements 

### were required, assumed,
or accounted for when developing the unitcosl fuctors. Some ahematives may have higher indired 

### orBOP capiml costs than others. Similarly, the inclusion ofgeneral facililies, preproduclion**~ud** invenlory costs, and other indirect cosls is 

### not known_ II is likely thatthc un1ity owner·s final total expenditure for the implemenlatiou ofthe allemallvcs, especially options that are mosl capital oost-intensive, will be greater than the calculaloo coot estimates_

• Locallon·specifio influences- mostNOx control techniques have been applied primarily to eastern bituminous coal-fired plants localednear large metropolitan areas, not in largely rural, upper midwestern United SIal"" locales_ The amolll1tofspare available is dependrnt on the exisllng powerplant equipment and building layout and property plot area, versus what is expected to be required forimplemcnting various control technologies. T=porlation and Jo<:allregionallabor costs are also variables.


# •

•

•

• Sizio influences

- some lechnologies' capital costs "'" more sensitive to "ceouomies ofscale" !han others_ Capacity maTgins

- some technologies' mayrequire higher cupueitymargins 10 allow sustained operation atoigh throughput rales over exlended periods oftime. Reliability concerns - some !eehnologies' have bcenrefined 

### to a nigher degree, and others may require more component redundancy toan others in omerto avoidporfmmance reductions and potential outages for failures and repairs orreplacements. fnfiallonary influences -the significant increases in 

### 2004-2005 for raw malerial oosts, especiaJly steel and aHoys ror fabrication ofstructural and mechanical components, 

### has occurred aflermany ofthese tec1mologie,o; were inslalled 

### in projects upon which the referenced unit capital oost factors Were b.sed.

Square**Bu~e** Electric Coopcrative**~.,** Bums & McDonnellAPPENDIXCl 

### Capilal Co'lEstimales

• M"rket condilions -as demand increases [01' emission controls, some allCmalives become more eosl-competilivc, while olhers do not. Tbis can be inflnenced by lhe relative supply and demand for lhe tedmology and number ofsuppliers who CUn furnish iL Thc**d~'rrumd** 

### for some ullenmli"", can also be strongly innuenced by the slringency ofthe local, SIHIC, Hnd nationul regulatory requirement,. Schedule for implementation and a,,"ilability nf1ocaJ!rel,,;OIml bbor lor installalion conlmctors ore a1.,o market_driven**f~dors.**


### The**eSlim~led** 

### NOx conlrol cosls are in addition 10 Capil;]l cost.>; 10 provide normal repbeemenls oflhe existmg Millon R. Young Station's majorpowCT generating equipment.



### C.2.1 Separated Overfire Air Capital Cost Estimates InSlallalion ofseparaled overiire air systems tyrically includes windbox an<J!or secondary combustion air supply duel modificatious. boiler waterwalll.ube openings, air.oow distribution device, (dampers/registers), airllow conlrols and me"surernent instrumentation, and relaled siruelurnl ""d electrical lie-ins l.o 

### lhe exisling plant faeil ilies_ A basie separaLed overfirc airrelrofit syslem inSlilllcd 011 a lignile-frred cyclone boiler includes poru**~cro,"** 

### lhe front and rearwalls ofthe upper fumace. The w,il eapital co,t faclor is expeeLed 

### to bc ubove the high end o[the lypieal published eOSl range of$5-1 0/k\V'; ($1 1.5/kW or $5.500,000' for MRYS Unit 2), due to the lurgc ducl.'l, rdutivdy lall fllTrulee (compared 10 typical bituminous eoal-fired eyclone boilers), und theneed to "void existing obstructions wilhin the boilerllOuse_

An 

### adv""ced form of

### SOl'A unique to North**Dakot~** 

### lignite-fired boilers will include relocation oflhe existing lignite drying sysLem ventport openings from lhe lower primary lilmace 10 the upper**furn~ce,** 

### 10 be pluced**~t** 

### 'he same clcvation as lhe new SOFA ports. This requircs exlension ofthe exisling cyclones' lignite drying syslems' vent piping 10 supply Ihc nCw boiler fllTllilce ports. This retrofitwill also c1115e-<lff the existing FGR ports in lhe lower front and rear fumaee walls ofUnit 2, eurrcnUy coinciding wllh 

### the cAislmg pre-dry 

### velll ports_ These FOR ports maybe blocked, orrelrn:ated to 

### the lower portion oflhe upper(sGCondary) furnace, across the lronl ""d refIT \V.lls. This is expeeted 10 eost In 

### Ihe UTe_ 

### of +$9.5/kW or $4,500,000 lorUnit 2's additional eapiml eost over ""d above the basie SOl'A system. Overall, Ihe advanced version o[ separated**oV~TflTe.ir** 

### technology is estimated 10have an installed capil:ll cost ofapproxim"lely $lO_O Million ($21.0/kW) forMRYS Unil2_

Borns & McD""nell**Sqll",~** 

### Bulle Eleelric CooperaliveAPPENDlXCZ C.pilrll Cost**E,~maleS** NOxDACfAnalysis Study


### C.2.2 Reburn Capital Cost Estimates C.2.2.1 Coal Reburn Capital Cost Estimates There is one ahemative that**inclu~cs** u neW cool rebum syslem. Capital coste.,timates for coal rebum systems 

### are highly dependent on the requirements for rebunI fuel Jlf"I'"Jl1Ition and feC<1ing lo the boiler. For the purposes ofthis analysis, thc application ofn pulverized coal rebum system "<Slimedthe need to make extensive additions 10 the existing fuel preparation eqnipment in the existing plantfacilities "nd feeding to new furnace injectors. At l""st two neW fine-grind pulverizers, or MPS"89 stand"rd pulverizers followed by dynamic classifiers are expected to supply the amOUnI offinely ground reburn coal for ll1is method.

Addition ofnew c1cclricolloads for the pulverized coal preparation equipment 10 the existing plant facilities will be required. For the purposes ofthis prelirnirurry sludy, it is assumed ll1at additionnl plJIlt auxiliary electrical powerwill be available for powering the new pulverizernlmicro-mills nnd related new coal rebum eqnipment, but this has notbeen conl'irmed.

_The existing crusherb,ys do nothave £loorspace avaibble to nllow thcnew milling equipment forrebum

fuel preparation to be located adjacent 10 the existing coal cnJ.-'bers. This will require a separate building**,,~r** addition to the existing powerhouse to be buill 10 provide sufficient space to enclose !he new milling and coal silolhandling equipmenL Separate modified pulverized coal-style burners or coal injectors will 

### he installedtlrrough new openings ill the upper furnace front and rear waterwalls at Orabove the elevation ofthe existing lignite drying system vent ports, along with new overfire airporls located at a higher elevatioIl, above the reburn fuel injectors. Ibis would have the capacity to supply approximately up to thirtypercent ofthe IOtal full load fuel heat input to the boiler through the coal rebnm injectors. This coal reburn system design was not expected to change the existing cyclone silo/feeder ammgcmenl, such thar nll cyclones wonJd remain operational. To achieve ll1llXimum

### NO" emission CAlTltrol, only the adVlloced fonn ofSOFA for pulverized coal reborn was included. Confirmation ofthese concepts and COst estimates requires more detailed eqilipment design and plant layoIlllhan has beenperformed for the purposes ofthis BACTanalysls.

The installed capital cost ofpulverized coal rebum for the cyclone boilers atMilton 

### R. YOUIlg Station used in this cost effectiveness analysis Was estimated based upon a Clean Air Markets Division [CAMP] oftheUS 

### EPAdollarper kilowatt unit capital cost factor for cyclones. The installed capital cost estimate of$40.65 Million for MRYS Unit2's pulverized coal rebum alternative used in this cost effectiveness analysis was estimated based upon applying a 3.5% assumed inllalion 

### cost adjustmentto ll1e CAMP unit SquareButteElectric**Coopera~ve** C2-3 Bums & McDonnell**NO~** BACT**A~alysis** Study APPENDlXC2 Olpilal COSI Eslima!as capital costfaclor for cyclones of$82.33/kW (x 1.035 = 585.2/kW) included in a WRAP (Wc'lern Rcgional AIrParlncr,hip) draft repod' published on lheirwebsite, dated April 26, 200S. 1be cost 10 relocate the lignile drying .'yslem venlports and FGR ports was added [0 the inflalion·adjuslc<! CAMD number ($85.2 

## + $9.5/kW = $94.7/kW), since coal rehum IS expectedto include .,eparated overfire air hut not lhe exira costs for 1hc special improvements identilied for air-slaged lignite-liring in cycloLle boilers. This increased the installed capital costby S4.M [or MRY Station Unit2's coal reburn systcmlo a lotal of S45,154,000. This docs noL include the additional paJticulate matter collection capaciry**consid~'rCd** necessary to limit the expected negative**imp~cl** on opaclLy from 1his option.

To conlrol**pnrticul~lc** malto.'T (PM) emissions**~lat** would be expected to increase irom insmllalion and operalion ofpolverized ormicronized coal (cburn, adt!ilional PM collcction capacity ",ill be requil'ed. A hybrid fmnl ofPM collection Ihat snpplemems lhc CJ\isting**clcclrosl~tic** prccipilalor's pcrfornlanoe, referredto as COHPAC (COmpact Hybrid PArticublc Collector). This was**es~nmted** in 2002 doll"rs al 330,200,000 [or MRYS Unil2's CUllPAC'. Adjmtedby an esoalation mctor of 1.2623, ilie installed cap'tal cost ofthe COlIPAC addilion was**c;stim~te<l** 10**b~ ~36,013,000**  [or MRYS Unit 2 in 2006 dollars, When thc COHPAC add,lion**w~<** combined with the Lignile lleburn and ASUFA allemalives, tim resulting tolal cstimalcd capilal cost, were $81,167,000 for MRYS Unit 2 (£94.7 

### + 375.5 S170.2fkW).



### C.2.2.1 Gas Reburn Capital Cost Estimates Convenlional gas ",bum oplions assume lImt seventeen percent ofthe tolal fuel heal input 10**Ih~** boiler is through the neW gas reburn injectors to be located in lhe lower secondary furnacc abovc the lop rows o[ cyclones. Eighl to twelve gas rehUffi injeclors wouldbc cXp<'cted 10 bc rO(jllircd in lhis case. Seven percenl ofthe total fuel heat inpul lO the boiler lhrough the gas rebmn injeclors is a,mmed 10 bc supplied for the fucllClm gasrcbum alternatives. Fonr to eight ga, rebum injeolors couldbe assumed in FLGRTh<
cases. Gas rebum OptiOIlS assume that a new high"prcs'IITC gus pipeline woult!**b~** brought from ncar**Bism~rck,** ND approxirnulely Iwenty six miles. The pipeline diameter is prop<Jrtional 

### to lhc amonnl of :fuel required for the speeific alternalive, ranging from 24 inches for convcntional gas reburn to 12 inches for fuel lean gas rebmn cases. A station gas man;., "Iilh new gas lrJins, consisting ofvalves, metering,
anu safcly shutofrvalves [or Ihe front and rear hoiler forthe 

### gas injeclors' supply, woulll 

### be furnished and installed.

The**c~pllal** oos[s for conventional ga, rebnm allemalives wel'e eSlimale<1**consid~'ring** unit capital cosls pnblished in published lechnical literalure. One vendor lhallms supplied numerous domestic utilityboiler

BIllllS & MoDOIU\ell Square DUlle Ekclrio C.ooperalivc

### APPENDIXC2 C.pilal Co,t Estimates NOxBACl'Analysis StlJdy

'." 

### gas rcbum systems (GE Energy, formerly GE-EER) published $IOIkW for gas reburn in a 2001 technical paper'. Anothersourcepublished a 2005 technical paper'" that provided a unit**c~pital** 

### cost range 

### for gas reburn of5l15lkWto 5I30IkW. Neither source ineludcd a detailed scope descriptionnorcoslbreakdown [or engineering,**equipmeIl~** 

### materials, and labor to install a gas reburn system.
Site-specific needs and challenges identified for**~pplying** 

### conventional gas reburn to Milton 

### R Young Slation, and lack ofdefailed gas reburn project scope and equipment desoriptions avail"ble in published technicalliterarure leads to a muoh greater degree ofuncertaintywith regards to an 

### aCCIrnlte capital cost estimate for this alternative_ For the purposes ofU1is study, the estimated instal1ed capital cost for a conventional gas reburn system \vith advanced SOFAonMRYS Unit2 is expected to be approximately $20.5M (S43/kW), which is above the lOp end ofthe previously stated 

### rnnge. before adding the new \!IIderground gas pipeline capital costs. This study assumed an 

### average unit capaoity capital cost factor of $22/kW forcouventional gas reburn, plus the additional CoSls for the adv""ced fonn nfSOFA Over basic SOFA +$4.5M ($9_5/kW), and the new high-pressure gas pipeline. This results in a 

### an estimated installed capital cost for conventional gasreburn systemwith adv"nced SOFA on MRYS Uni! 2 of$20.5M ($43/kW) plus the new high-pressure gas pipeline costs. Confirmation ofthese conoepts and <:(1st

C 

### estimates requires more detailed equipment design and planllayout than 

### has been perfonned forthe

purposes ofthis BACT

### analysis_

Fuel lean 

### gas reburn (without SOFA) capital cosleslimales werebased upon a lale 2004 budgetary proposal"" by avendor (Fuel Tech) wilhexpcricnee in supplying FLGRTM equipment, typicallycombined with an 

### SNCRsystem. Estimated capital costs of$JM inclnde budgetary numbers for the equipment installalion, including inslallation**managemen~** 

### material and labor, with a +6_0% price adjustment assumed for477 vs 450 MW 

### for a fuel lean 

### gas reburn system without SOFA on MRYUnil2, uot including the capi1lll coslfor the gas supply pipeline. Costs for

### workoUlside the vendor's scope, such 

### as balance-of-plant additionsplus other indirect oosls were eSlimated lo add approximalely $l.IM (25% plus 10% contingency) lo the adjusled vendor's estimated inslallcd cosl 0£$3.2M for U1eir soope ofsupply_ These udjustrnents result ina lotal installed capilal cost for FLGR (without SOFA) estimated to

### be $4.3M plus the capital cost for the gas supply pipeline. Adding the incremental costs forthe ndvanccd from of SOFAovernO SOFA (+SIOM ($2l/kW) results in an estimated installed capilal cost for a 

### fuel 

### gas reburn system with advanced SOFA on MRYS Unit 2 

### of$14.3M ($30.01kW) plus the newhign-pressure gas pipeline costs.

Square BuneEl""trio Cooporalive Bums & 

### McDonnell

### NO"IlACTAnalysis Srudy APPENDIXC2 ('''pllol CO'1 Estimalo' The capi",] oost eslimares for the new high-pressure underground gas supplypipeline assumed $7 per ineh ofdiameler peT 

### foot oflength_ This WaS calculaled 10 be approximately $23M for conventional ga' 

### rebuming**~nd** 

### SI1.5M [or FLGRTM_ The cosl analysi., for eaeh NO" control allernative im,-olving a parlicular fuml ofgas rcbum assumed lhal both hoilers at MJlton R_ Yrmng Sialion select the same allerLlaj ive 1J,atburns natural gJs. There[ore, the eslimated capilal cosls fOT gas rebum alternatives rdlecl
a capacily-based proportional share ofthe cas pipeline capital oosts, avoiding double-oounting. Thi, rcsulls in nn eSlimaled inotal1eu capital cost for MRYS Unit 1's share ofthe ga, pipeline to he 

### $15M for the conventional gas rebum alteroative al,d $7

..IM for fucl-lc'm gus rcbum allcrnalives.

The (ut.1 insl<llled Cilpital cus(s fur conventional**~s** 

### reburn (with ASOFA) witb MRYS Unit 2's share of the total capital cost for the gas supplypipe1ine eSlima(cd 10 be 

### S35-5M**(S7~AIkW).** 

### The lotal ;ustal1<0 capilal cOSlS forFLGKrM (Wilh ASOFA) with MRYS Unit 2's share oflhe total capital cosl for the gas supply pipeline were eslimated to he $2J_8M 

### ($45.7fkW). Conlirmmion oflhese conoepts ami co,l eSlimates requires more detailed equipmcnt dC'lgn and piJnt byuullhan has been performed for lhe purpus,,", ofthis BACT analysis_



### C.2,3 

### SNCR Capital Cost Estimate The allcrnal;vcs that includo sclective nou-calalytic reduclion s)'stems assume the use ofurea unless noted otherwise. The SNCR systems' prelimina,y design and estimated capital cosls were based upon a 450 MW lignite-fired cycloneboiler in Mo 2004 blldgelary propusal' by a vmdor (Fuel Tech) with expcricnoe in supplying SNCR equipment. Circulation, metering, dilutiun, control, Jrld**injec~on** 

### equipment 1S inclUded. A 180,000 gallon field-erected ,,-taioless steel slorage tankwill hold lhc 50% urea solution (as delivered by 

### truck). Individual and multiple nozzle lances wilh mulliple levels ofurea r<:agent injeclion will he designed and localed to uptimize distribution and aecumruodale various builer load condihons. EsLimaloo capilal cllSls ofS4_9 Million includehudgetary numhers for equipmCIlI instal1alirll!, including installation**manngom~~l,** 

### malorial anrllabor assumed for a SNCR syslem applied tu
a**~50** 

### MW boiler. Costs fur work uulside the vendor's scope, such as ouldoor reagent ,torage tank and building enclosure/equipment frrundalions and containment, and**halance-oj~phll1t** 

### addilions plus other indireet costs were estimated lu add approximalely $1.9 Million (25% plus 10% contingency) 10 the vendor's estimated installed cost for lheir scope ofsupply_ This results in an eSlimaLcd lollli capital COSl for 5NCR (withoul SOFA) of$6_8M for a450 MW lignile-fired eycloneboilcr.

Bums & 

### McDouueU C2_6 Sguare Ilu"e Electric Coope",tiveAPPENDIXCl Capital COSl Estimates NOx BACTAnalysis Slody



### .-**.~** Applying these adjustmenls 10 a 477 MW boiler results in an eSlimated total installed capital "osl for SNCR 0[$7,120,000 [orMRY Stalion Unit 2 (SI4.9/kW).



### C2.5 Layered Technology Capital Cost Estimates Capital costs 

### were general]y estimatedbased upon simple arilhmelic**addi~on** ofindividual nnil oUlpul capilal cosl faclors [orcombinalions ofavailable NOxreduction leclmologics, such as SNCR wilh ASOFA. An advanced form ofseparaled overfjre air system included !he lignile_fired cyclone boiler cquipmenl changes within !he eslimatcd unit capilnl cosl [aclors.
Adding the advanced SOFA capilal CAlst of$10.0 Mi11lon 10 the previons estimaled installed capilal cosl of$7.12 Million yields a tolal estimated inslalled capital costof$17.12S Million ($35.9/kW) for the SNCR with ASOrA altemaLive [or MRYS Unit 

### 2.

As previously discussed, Lignile (coal)Teburn (CR) was assumed to be combined \vith "dvanced SOFA and a COHPAC addition considerednecessaryto limilthe exrected negative impacton opacity from !his option. The installed capilal cost ofthe COHPAC addition WaS estimated 10 be $36,013,000 [orMRYS Unit 

### 2. When thc COHPAC addition Was combined with theLignile Rcbum and ASOFA allematives, the**reruJ~ng** total estimated capital costs were $EI,167,OOO forMRYS Unil2 ($94_7 

### + S75.5 = SI70.2/kW)_

Square BUlle ElecLric Cooperalive 

### eM Bums & McDonnell

### IAPPENDIXC3 O&M CostEslimates NO"BACT Anaiysis Study



## , ",

## . 

# .., 0

"

0



### ;.

## -: C.3 Operating and Maintenance Cost Estimales for MRY Station NOx Control An evaluation was performed 10 delermine the eslimaled operating and maintenance cost impacts of installing and continuously**opcr~ling** various feasible NO" controllechnologies on Millon 

### R. Young Stalion Unit 2. These were estimated 

### to be in addition to existing O&M COSls 10 operate and maintain the :MRY SUllion cquipmcm.

The expected loss ofelcctrical power sales from the operalion ofthe specific 

### NO", control altomalive was included os an annualized cost, assuming $35 per megawatt-hour. This was determined (0 indude estimates for:

• Reduclion in annual unit OUlput due to an expecLed negative reliability (i.e_ uptime availability) impact for each alternative. This generalion reduction was calculaledby mulliplying the esliIllilted additional numbers ofoutage hours peryear

### by thc averagc runningplant capacity factorfor that specifio altemalivc,**mu\(ipli~-d** by the historic 12-month average unit gross electrical power output

## (MWJ dd.rrnined during lhe same period as the highest 12-monlh rolling summation 

### NO;.: pounds. Net adclitional auxiliary e1ectrio power demand for the added control cquipment for each specific alternative based on assumplions for b'rOsS horsepower, plus additional power demand for existing 

### funs caused by 

### flue gas prcssare drop (COHPAC for additional PM oo11""tion e;apacity), with adjuslment for expecled reductions in power demand (such as a d""rcusc 

### in existing coal crusher and feeder electric demand for the pulverized coal rebum casc). The averuge rulllling plant capacity f,,-cLorfor each alternative, which may ,,-Iso inclUde an expecLed negalivc impact on the unit capacity from operalion oftheieelmology. This assumes that the control technique limit. the gross electrical power output ofthe Unit (such as causing an increase in flue gas flow) such lhal thc 

### fuing TIlle ofthe boiler C31U1OI be lllilinlained orIllised 10 compensate for lhe load impact. Examples are lower boiJertbermal efficiency (highcrunitheat rale) when firingnatllml gas (due to higher moisture conlenlofthe fluc gas).

For llic SNCR allcmalive!h:ltinvolve. a

### ehemic~l reagentinjeoled forNOx control, such as urea, lhe annual reagenl COJ15umption based on an assumed aclual sloichiometric ratio (ASR) ofmoles of equivalent 

### NH, injected per mole ofuncontrolled NO", emission estimaled !rt llie point ofinjcction, converted lo a mass rale (lb&Ihr) 

### by multiplying by the eslimaied annualnl1IIlber ofhours ofoperalion and thc eslimaLed 

### NO!!: reduction m.clion, and then multiplied 

### byunit reagenl cost (for a specific inlet NO" concentration, cmission reduction percentage and ammonia slip level).

Squmc BurLe Electric Cooperative 

### BIlIJIS &MeDonnoiiNOx BACT Analysis Sludy APPENDIX C3 O&M Cost l'..stimalc,

Gener,,] annual maintenance cos1s**W~TC** assumcu 10 be 1.5 perccnt ofihe**eslim~lcd** inslullC<! capital cost for each alternative, except for the coal conveying and grinding equipmenl portion oflhe coal rebllIn altemalive. which was assumed to be 3 pelcenL The periodic bag replaccmenl costs and other COHPAC sy>lcm**m~inlenaTlce** cosls were cotimalcu 10 be approximately 5.3%**oflh~** inswlIed eupilal cost ofthe additional particulate malter**col1e~tion** equipment.

Additional nperating lab",· costs directly allribulnbk 10**co~h** olt=alivewere assumed [0**b~** zeTO for ,n alternalives.

Olher operating costs include:

• Reagenl dilution waler for Ihose oltcma1ives [hal involvc a chemical reagcnL injcctcd for NOx control, typic<\lly four times the amount ofurea consumption (assumes urea is a 50% solulion os delivered and is injected a, a 10% solution); this follows EPA OAQPS convenlion' .

• Healrcquired for UreafCagent sloragc, for those "hcrn"tives Ihal involvc a chemical re"genI injected for NOx control; Ihe source ofheat is aS5umed to be auxiliary electrical power, but could be auxiliaty steam (depending On heal sOurce "vailHbility Hnd plant**prefe'r~'Il"c).**

• Additional coal consumption for**thos~** alternatives that involve a chemical reagent in jecled for NOx control to compen,ate for Ihe heal ofvaporiza.tion ofthe reagel\t dilution waLer; This follows EPA OAQPS convention', but is not accepted practiec by an experienced SNCR vendor (Fuel Tech) who claim, that the heat produced from the exothenllic reaction ofur." and NOxis approximately eqnal to tile heJl required l(> evaporate the dilution water. For lhe purposes ofthis study, this addirional coal eOnlurnption has been ineluded in**Ih~** annual O&M cost._

The sum ofthe estimated "nnual O&M cost, was multiplied by the O&M leveli7.alion factor (1.2487J) for each alLernahve to yield ]evcli:I.Cd tot;,1 annual 0&]1,( oosls.



### C.3.1 Separated Overfire Air O&M 

### Cost Estimate Opcmtion ofSOFA is expected 10 add u small amountofO&M cost, primarily electricity consumed by the c(mventioruJl SOFA damper electric drive actuator and airflow measuring system transmitter on each port. Using the exisling forced 

### draft, induced dlllft, and flue gas reciroulation fans is not expected to change the overall amount offun horsepower demand to be snpplied by those fans' electric motors. Maintenance ofIhe new overiire air poris and relocated lignite drying system ventports (and FGRport,

Burn, & McDOlmell Square Dune E1eclric Co"l'eroliveAPPENDlXO O&M Cost 

### Estimate' NO" BACT

### Analysi, Study



## , 

## . 

# 1* i 

# '" 

# i--§ I**.~.** 

### for Unit 2) 

### is included, assumed to be 1,5 

### percentofthe installed eapilal COSI. 

### This is included in every control alternative's estimatcd O&M 

### cost.

SOFA is not expected to significantly reduce unit reliabilit)l and availabi\i1y lo generate electricalpower, assuming consistent combustion and continuous slag tapping under substoichiometTIc air/fuel operating conditio"" forMRYS boilers cm be routinely established. 

### A Unit uvailabilit)l reduction of

### 2.2% (IB 1 hours peryear), fot 

### M_R. Young StationUnit 

### 2 was assumed, which allows forforced or extended scheduled boiler outagcs tbatmay result fromproblematic cyclonc slag tapping opemtional conditions encountered during substoichiometric cyclone operation with SOFA. Thc expected loss ofelectrical power sales from the reduction in mnual electrical power output due to 

### a decrease in expected Unit availabiJjt)l from ASOFA opemtion is included in every control alternative's estimated O&M cost.

Boiler fumaoe wmcrwalltube maintenance may increase slightly as a result ofmore fireside oorrosion due to suhstoichiometric cyclone opemtion with SOFA. There may be some changes in the degradation rale oftheboiler's furnace waterWali tubes resulting -from exposure ofmore area ofthe furnace waJ1s to 

### slightly air-lltarved conditions during SOFA operation. Such conditions can promote corrosion from 

### sulfur compounds in the furnace gases being created above the cyclones and below the SOFAinjection porK Due to the relatively moderate arnOlUlt5 ofsulfur contentin the lignite, modestamounl ofairstagingofthe existing cyclones dUTing SOFA operation, andthe potential use of recirculated flue gas along_the lower furnace walls, the cxpected change in corrosionrate oflheboiler tubes should be minor. TIlls degmdalion is expected to 

### occur over many years ofoperation, andnorrnallyrequires periodic replacement ofthe deterioraled sections ofboilerfurnace walerwaJl tubes to 

### avoid forced oUlages to repair tube leaks or failed secllOllS_ The additional cosU> assooiatedwith 

### potential ohange 

### in the fi:eqUCllC)l 

### offurnace wall lube fililures and chang.outs are 

### difficult 10 

### eslimate, andhave nolbeen qlllmtificd.



### C.3.2 Reburn O&M Cost Estimates The**allemali~'es** 

### that include a new coal rebum syslem assume lhe use ofnewequipment forpreparing lhc rebum fuel toreplace 

### 25% of!he MRY StationUnit 

### 2 boiler's lolal fuel heat inpuL Two additional lignile sil"" with coal feeders and fine-grind pulverizeJ"s followed by dynamic classifier(s), are assumed tobe located in a new separate building or powerhouse enclosure_ Booster fanes) addition was locluded becausc!he existing forced dro.n fans Were assumed to be incapable supplying the additional amountof primary air to the fiue-grind pulverizers and dynamic elassifier(s) forprocessing and conveying the rebum fuel. Using the existing forced draft, induced drnfl, and flue gas recirculation 

### fans is not expected
Square BulteElectric Cooperative C3-3 Burns & 

### McDonnell

### NOx BACT Analysis Sludy APPENDIXC3 O&M 

### COSIEslimalos
to .<ignincant]y ohange lhc overall amount offan horsepower dcmandto be supplicd by those faJ18' cl"clric molors. The expecled loss ofekelricul power suks from lhe additional auxilisry eleotric power demand for lhe rehurn millmg equipment from an e.,timaled 05% (25 MW) 

### redl1clion innet oUlput WHS 

### induded as a eo,t, a,"uming $35**p~"r** 

### megawatt-hour for MRY Slatioll Unit 2. EIcclrieal power cO<lSumcd by Ihe inGrc"'ed lo"d on boiler failS 

### to**Ov~rcome** 

### the higher flue gas system pre;;sure drop, plus lhe COlIPAC 

### pan:ieulale colleclion ,)'Stem support equipment 

### was eSlnnalcd 10**b~** 

### a 1.2%**(5.~** 

### MW) reduction in net outputfor Unil 2.

M"inlcnanee oflhe separate rehum coal injeclors, fuel "nd primary airpiping, and relJum fuel milling equipment is expected to bc similar to lhe expenses a.'''''ciated with Iypical pulvcrized coal burners. The eSlimated additional annualmaintenanoe cost!; for a nCW micronized eo.l rebum system was assumed to be 3.0 pcrccm ofthc installed capital cost, or roughly $1,355,000 per year, for MRY Stalion Unit 2_ The eslilllilted additional annual maimemmcc co,l, (inflation adjusted from 2002 to 2006 $) 

### for lhe COIJP

### AC system wa;; appmximale]y 

### SI,938,OOO peryear for MRYS Unil 2. Boiler**f\lm~cc** 

### waterwaII tube and 5uperhealcr/rehealer tube maintenance may incrcooc slightly as a 

### result ofmore erosion due 10 increased particulate emiS3ions or IQuling by fly".m deposits resulting from coal reburn openllion with ASOl'A. 

### The additional costs associnlcd with potential change in the frc,!ucncy ofbOllcr tube failures and changeouts are difficult to estimate,**~nd** 

### h.vc nut been quantified.

The estimated impads On opCl1l1ion and maintellanoe costs for Ihe**co~l** 

### rcbum allemalive lhat include a
new pulverized ormicronized coal rebllITl system ore approximate. The twelve (Unir 2) exisling coal crushers forpreparing lhe main (oyclone) fuel .fraction will have slightlylower eleolrical lk"mand. This wa., estimated a;; -0.45 MW (-0.09%) 

### forMRYS Unit 2_ 

### Addition oInow c1eelrie.1 loads forthe micronized co"l preparation equipment 10 Ihc exi5ting plant facililies will be required. For thepurposes of**~lis** 

### preliminary study, it lS 

### assumed that addilional plant am:iJialj' electrical power will be availablo [or poweringthe new pol 

### veriV'rSJclassiflers and 

### rei aled new coal rebum cquipmenl, but tlJis has not been confirmed.

Coal Rellnm with ASOFA 

### is nOl expected 10 ,ignificanlly reduce unit reliubility and availability 10 

### gencralc electrical power, ",,"uming consi,1CIlt combustion and conlinuous 81ag tapping under sub51oiehiomelrie uir/fuel operaling conditions for MRYS boil= ean bc roulindy established. 

### A Unil availability reduction of3.7% (3.8% 

### (3 13 hours perycur), forM.R. Young Station Unil 2 wns uS3umed, which allows for forced or 

### extended scheduledhoiler outages Ihat may rcsull [rom problematio operalional condilions encountered during coal rehum operation wilh ASOFA. 

### This reduction in allllual

Bums & 

### McDonnell C3_4 

### Square Bull<: Electric ("oope-rali\'"APPENDIXC3 O&M Cosl Estimate, NOx BACfAn.lysis Study

<,.'

### '~



### "." electrical power output due to a decrease in expected Unit availability is included in the cnal rebum oontrol alternalive's estimated O&M: cosL

A Running Planl CapacityFaclorreduGtion of0.5% ofannual gros. electrical output was assumed for the cool rebum alternative. This would result in an estimated 22MW average load deorease forM_R- YOlmg Slolion Unit 2_ This expecled loss ofelectrical power sales from the reduction in netoutput due to lhis plant ""pacily impact 

### was included in the estimaled annual O&M costs.

Conventional and fuel-lean gas rebum options will involve higher operating wsts compared with the existing operalion ofM.R. Young Station_ Nalurnl gas supplywas assumed 10he available near Bismarck, 

### ND, butiliis has notb",," confinned The eslimaled unit cost oflhisnaturaJ 

### gas was assumed 10 average $7.9S1million Btu on a levclized annual co.thasis, with a "credit" of$0.71 permrnBlu for avoided cost ofoonsumption ofJignite cool reduccd by ihenatural gas heat input. The estimated annuai cosE ofnatural gas for the conventional gos rebuming aUemativc appljed 10 MRYS Unil2 is approximately S50_3Mpe.ryear. The estimated annnal cost ofn.luml glls for the FLGR'IM alternativc appliedto MRYS Unit2 is approxirrultcly $20.BM peryear.
Thcnc\\' gas reburn injectors, station gas m.in and injector gas trains would Slid a minor amountof expense 10 currentmaintenance requirements, assmned to be 1.5 percenE ofthe installed capilal cost.**Mainle~ce** Ofsep'file<! overfire airnozzlcs is expected 10 be simiiarto the expenses associated with Unit2's existing flue gas recirculation ports.



### C.3.3 SNCR. O&M Cost Estimate The alternatives that include selective non--catalyticreductiou syslems will involve higheroperating cosLs compared with the existing operalion ofMRY StationUnit 2_ Urea reagent supplywas confirmed to be ,vailableregionally. The estimatedunit cost ofthis 50"/0 aqueous urea solution WlIS assumed to average approximalely $379!lon delivered (2006$)_ Consumption ofurea reogent for SNCRwilh ASOFA was


### , basedupon preliminary uumbers aHowing for a boiler nue 

### gas exitarmnonia slip of5 ppmvd. These
were estimaled as approximately 286 gph for SNCRwhen applied 10 MRY StationUnit 2 with ASOFA.

New electrical loads 

### arc requircd for high now 

### urea circulalion, in-line and slorage tankheating, water di.lution, and reagent metering equipment. ·These ,uxiliary electrical demands and reagent dilution waler usage were oaloulated based upon equations published in EPA Office of

### Air QualilyPlanning;md

Square Butte Eleotric Coope""ive C3_5 Bum, & McDonnell

### NO,,13AcrAnaly,is Snldy APPENDlXC3 

### 0&0\1 Co'l Eslimates**S~"nllunJs** 

### (OAQPS) publication EPN4521B-02-00J. Seclion 4.2, NOx Conlrols

- NOx POol-Combustion, Chapter I _

### Selective Non-Cutalytic OxidationI. 

### Compressed niffor reagent atomi&llion and lance purging anll couling, as well as lllulLiple nozzle lance wal", cooling are allJilional demand, on the existing**pl~nt l~eililie".**  

### These powerhouse bUllaing scrviee supplies were a,slImcll 10 

### be available, but thi, has not been confirmed. The new llfea reagent injection nozzle lances, reagenl p"rnps, dilution wuter pumps, anll Jlstribulion piping/valve 1rains wOllIll 

### "<1l1 " minor amount ofexpense to ourrenlmainlenanoe requJremenb';, asslImed to 

### be ].5 perceLlt ofthe installed capiwl cos!.

SNCR wilh ASOFA is not cxpecled 10**significan~y** 

### reduce un;' reIiabihty and availability 10 

### generalC c1eclrical power, as""ming urea lIljection does nol impact lhe abilily 10 

### maintain consi,lent combustion and conlinuous slag tapping undcr SWbsloiohiometric airlfuel operaling conditions lor MRYS boile". A Unit availability reduction 00_2% (263 hours peryear), for 

### M.R. Young StatIOn Unil 

### 2 was assomed, which allows for forced or cxtended scheduled boiler outages lM L 

### may rcswll from problematic openltional eonJitions encountered during SNCR·rclalcll opEmtion withASOFA. Thi. reduelion 

### in annual electrical power outpu L

### awe to a decrease in ""peetedUnit availability is inclwded inthe these control allemalivcs' cSlimJlod O&M costs.**~!:**

A 

### Running Planl Capacily FJctor reduclion ofO. 15% 

### ofannual gross elcelrioal output was assumcll [or Ihe SNCR wilh ASOFA alternative. ·Thi., would reswlt in an c,limu(ell 0.66 

### MW avemge load clccrease forM.R. Young Slation Unil 2. This cxpcclCd loss ofeleemoal power sales ii'omtbe reallClioll in net omput due to this plantcapncity impact was induded in the cslimalcd annunl O&lVl costs.



### C.3.4 Layered Technology O&M Cost Estimates Operating and mo;nlenance cosl_ for 

### combinations ofavailable NOx**reduc~on** 

### technologies Were estlmated based upon simple ariihmclie addition ofindividual cosl eslimales_ SNCR was comhined with advanced SOFA, as previOl18ly shown. Pulverizcd coalrcbwm wos assumed to 

### he combinccl with advJnced SOFA (and a COHPAC addilion for

### PM controJ)_ The auxiliary electrical Jcmands and reagent dilulion water uSJge for SNCR "11th ASOFA were calculaled basednpon eqwaliOJls pwblished in EPA Orrice of**AirQu~]ily** 

### Plunning and Slandards (OAQPS) publication El'Al45211J-Q2_001,**Scc~on** 

### 42, NOx Conlrols

- NOx Post-Combwslion. Chapter 1- 

### Seleclive Non-Calalytic OxiJation'

.

Bums & 

### McDonucll C3-6 Sqoare Burte 

### ElecTric CooperntiveAPPENDlXC3 O&M Co,t Estima,es NOx BACfAnalysis Study


### C.3.5 Summary of O&M Costs Estimates for MRY Station NOx Control The results o[this evaluation for estimated variable operating and maintemmco cosls for lhe individual NOx control allematives arc summarized in lhis section. lbe expected reduclions in Unit availability (nptime) and capacity are included in Tables C.3-1 throughC.3_7 [or MRYS Unit 2_ Tables C.3-5 and C-3-6 for MRYS Unil2 include the eslimaled urea reagent and dilution walerusage rates and cosls for tho ahenmlivcs !hal involve SNCR \vith ASOFA NO" control lechnologies.


### TABLE C.3-1
- Expected Availability Reductions for MRY Unit 2 NOx Controls

( ) p y go g pcrccn oge (2)-,- 12·montbbaseline availahHity i< ",umed at93.9 perC<nt. Thes. values re.Oeol c<lima,ed """,un'" ofneg:nive ·reliabiJjty impact**e~pe,l<:d** from tho implomenlalion 01**L~O** individual NOx <:ontrol teclmiq"o, (3)

- Annual opCIaling lime l. annual ,.orage availability 1IIllllipliod by &760**hr~yr** ofpo"';bl< uplime. (4)- Ann""l ou,"go lime i< S7@hrslyrpo"ibleoperaLing Limo minu, <:stimaled .nnual oper.mng ume. ('i)

_Annual op=ling time m1uc'ion ,,,uhing liom the implementaLion orth. individu"l NO" control**,,,,~nique** i, tbo difference between lho basc1ino and e:<pc<:!cd annu,l onWgo limes. E,timalell Annual Average Unit Operating Time
Unit Unit Unit Operating Outage Operating All. UUi\tyf'l TimeD) Time'<) TIme Reduclion'5l,**Label~)** 

## , brsIVr' NOi Control Teeltoique AvaUabitit 

# - ltrslvr E SNCR wi ASOFA 0.909 7965 

# '" '" D Gas Reburn wi ASOFA 0.919 8048 

## m 

# '" C CoaIReburn wi ASOF/\ 0.904 ?916 

# "" m B FLGRwI ASOFA 0.919 8048 

## m 

# '" A AdV3I\COO SOFA (ASOFA) 0.919 8048 

## m 

# '" Basclino 0.939 8229 

### m 

# " , i'Jlem.,ive numberhas be<n =iou,l as,i cd from Ie"tn:movalto I\i l\esL removal 

# ,**S~uare** Bulin Electric Cooperative**B~ms** &McDorrncljNOx BACrAnaly,is Study APPENDJXeJ O&M Cost !'.slim.les


### TABLE 

### C.3-2 - Expected Capacity Reductions for MRY Unil2 NOx Controls

() Spy gh P g (2)

_ I**~_moolh** b_Iioo TLBmiog plam e:\l",'ily r,elor is assum,d aL 95.2 perc'nL The,e ,"diu,> reflecl ostimOl<d aLM<mlS of negarive rehabiliry irnpacL c>pcelod fromthe implem'nLal'"O oflhc individu,1 NOx conool Lechnique. (J)

_ Annual el'clTicily gon,r.tion ro:Iuction i, aM",1 up<:TIIting Lime ro:IuClion muluplied by the 'Mu"l r\lnning planL ""p"ciLy faolorre,ulling from**~"** jmplemcnlallOn afLIJe individual NO, conlroll,chniq"c multipli,d by ,he 12-monLIJ**av,,~ge** gross OU'!'UL or440 MW. (4)

_ Annual ol<omcily goncr;mon reduction <:<)sl i> Lhc annu,,] clccnio;ry geneLa/io" redu<:t,Oll (kW-hrsl,T)**rcs~l""g** from rho implomcntl'ion of,l,e indiVJdu,1 NOx cOlloQI Lechnique multipliod by 11.0 inrrcrncnt.1 \'ol"e ofdw"cily genera/iOrl, a""mod 10 bo SJS.OOfMW-llr. All w<I figu= in 2006 doliars. ESLim.led AllIlU.1**A,'er~ge** Unil Electric.l Power Gener"lion Reduciion from 0**cr~lill** Time Reduction IlniL lInH**Geoer~LiDn** Unit**Gener~Lion** AIL. Rllllllillg**Pl~nll" Rel!nc(inn~)**  Reduclion Co,t{'!,**L~bd')** NOx Conlrol Technique 

## c. adL I'actor kW hrsJ)'r 160D 

# ,



# , SNCRw/ASOFA 0.951 110,176,095 3,856 D 

### GasRebum wi "'SOFA**O.94~** 31,416,590 2,850 C CoalRebnmwi ASOFi\. 0.948 I30,n5.506 4,563 D 

### FLGR wi ASOFA**0.9~9** XI,91O,OH 2,867 A Advanced SO:FA (ASOFi\) 0.952 75,859.855 2,655 Baseline 0.952 0 0 

# ,
.. AILe,"a'ive de<i n"ion has bern reviousl ,,-«i,,""<1 from le.,L rerooval TO hi esL removal eree"I' e.

B or", & McDonneU 

## u-s Sqn.rc Bnlle Eleclric ConperalivoAPPENDlXCJ O&M Cosl ESlimates NOx AACT Analy,is Sludy Revised 1011712000 

### TABLE C,3-3

_ Expected Auxiliary Electrical Power Demalld Challges for MRY Unit 2 NOx Controls



# • (2)
- The APC NO, ",,<ripm,nl S"''' "u,iiin'l' eiectrk01 powcrd,mand ofalten,"i""" i, Iho sum ofIndjvidu,j**Icciulolo~i,..,** combjned by 'implo addirio,,- Ac'o,1 power

## de,.,,"", m,y diIT

.. from**~\i,** duo 10po,;ti", ar neg,uiv.**,yo",gisii~** .ITo,". Co'; ""urn jndud"**2,4~~** kW for fci:d p"'!"'ra,ion 'nd oonv,yiag 'quip,"e'l d'm"TId plu, 5.35] kW for Iho COl [PAC ,ystem ,driili"n for PM comm!. (3)

- j he AI'C NOx "'!uipment ,",ilb'Y ek",ricnl pow" dcm,od ""dit afconI rel>um altom,li,,'" Ihe ""m,l,dresul, of lawer cyclo"o "",I prep",'io" 'no fcoder rowe, "'m,nd due 1o iowarboihey",,,"e ,onl equjpmen' lu<\ding. >\C1",l powor dem,,,d, 

### '""y <liffer from the, due 10 ne<uracy or""lim.te, for",-,um,d ,mounl ofol"lRlin.g ho""p"",,,, redoctio". (4)

_The 10",111<'**nll~lr",'Y** ,I""";,,j powor demand ;, th, ,urn**of~le gro~<**  <lem,,,,! ,nd ,redi!. (5)

- 

## no on""ol ,·h'TIgc in APe NO, equjpmem aW<;lj"'Y cle,lri,"1 power**~",n,tu1** dec'rieily u"ge in kW-h""yr [0' lhe", ,Iremal;v,," 

### ;s lhe n,1 p""o' d,maru:i**mul'irH"~** oy lhe "limale<! an",",1 opcrd'iog lime aud nJ"ning pbm cnp,dty lactor whi,h reHeel< !he "dju"menllorany e,pe<red reliaoilily and e'p"ci'y impacl' fm,n Ih, illlplemonta,ion oflhe cOillmllccoo;que. (6)

_The :th"uoj ehoog, In APC**NO~** equipmeu' '",ili,'Y decrnc,Il""'I<"I,m'nd otcclridly eo,' i.<**I~o** aanu,j**ehon~o** in kW_hr.;/yr for 10"" an.mol;ves ""ulling rmm In, lmpi,men"'ti,," o['he indjviduol NO, e"nlrollerbnjqu, mUI!;pliO<l by lhe inerem'n,"1 ",Iu, of,u,Hj, 'Y clCdr''''lly 1eoo,an,,", .",um<XI 10be Sl'.OOIMW-hr, All co" liguro, in 2006 doH"",. Eslimaled Annua' A'.rage APC NOx Equipment Auxlllar, meetrioal Pon'er Dema"d ond U,a"" Gro" Toto! Nel Power Power Usoge 

## A" Demond'" Credir') Demond'" Usage'" Co'll'!, L.bel") NOx Conlrol T""hnique 

# 'W 'W .W kW-h.,.r r 100051 r 

# , SNCRw!ASOPA 13J_2 0 13J.2 1,008.774 

# " D Ga' Rebum 

### wIASOFA 

# , (228) (227) (i,724,42B) (60) C Co.l Rcbum wi ASOFA 8,J42 (4'i8) 7,394 59,217,554 2.073 0 PLGR 

### wIASOFA 

# , (12S) ( 124) (949,051) (lJ) A Ad""ced SOPA (ASOFA) 

# , 0 

# , 7,664 0; 

### ,,> Alternauvo**do,i~_tion** has beon pr<viou,ly ""j e" [rom Ie," removal 10 high.,.' ",mowl p""en"'il".

i 

# :kli$- 

# , " 

# ,.lfI;

SguafC BUlle Eledrio COUpcr,lI;ve CJ_9 Borns & McDonacli:-10, SAC 

### r A",dys;; Slud, Re\'i,ou 10; 17nOO()**AI'f'~NOIXCJ** O&]I,J Cu,l E"in"'lo, 

### TABLE C.J-4
- Expected AUl(iliary Electrical Power Demand and Generation Reduction Cost Changes for MRY Unit 2 NOx Controls



# , (I) AI'em",,", ,!e"gn"LOn hos b,en prc"Y,ou<ly "'''good hum 1 ••,1 ""TI","'! L" h,gh.,,;L "'ltIo,,1**p,rc,n"'~o,** (2)

_ Tho an"uol ,hong<: in**A~C** NOx 'qwpmenL 'll,!I;a,y d,,,"·'""[ 

### 1'"w", ,[eman,! 'k"rieily "lOg' ill kW.lmlyr I", LO"'o

..llemallVcs;••h.n".powerd.m

...**~mul.;1.li".lhy.he** ...im

...<1 oonuol opomILng 'imo ,edrunniog pi

.." C"p,,,,iLy r",lor whioh**"'~"l<** LfI, ,djll<"n'''L Ii" ,ny "'Po,,',,1 ",Ii,blhly :lml o"p:o,ily imp"ll frolll Lilo ,olplomO"','ion oflh, eom",1 L,'Chnlque. [ll

- An"",1 <lc"ri'ily g,ner"ioLl "ducolo" i' ",10",1 "per,ling 'im< ",<lu"io"**m"llI~li<~** by L!\e ,rum,1 mnning 1,I,m' c'p",ity r,eror r<,ulLing from ,ho**im~lo"""','ion** "rlbo ",li,',Llu,! 1'0, con"nl 'CChnoqllO LUulLipll'd oy U" 11._ LUon,h**,\'c,,~o** gro" oULpUL 01'4411 MW. H)

- Tho 10,,1 uni, 01."",,1 po",e,

### £"'''C.''''"**'~"ng,** i, Ih, ,urn ortho "mu,,1 eh,eg' in A['e**.~O>.** cq";j>'ne,,' ,""Ii,')' ,lcelri,,1 po\V<c dem'J\J ,I""rioi,y ","go**~I",** 'Il< ,nnua! d",rrlCJly**~,n,",lion** r"dncLiO'l ""uI'iLLg liom 'he implcm,n"'[on ofLho**In~i\'iuu,'** "Ih «m'1\1! ,,01\0;<IUC. (5)

- Tho Lotal unLl okwic-al 

## 1"'''''' £""e""""**,'h,"~"** '0" is Ih, '0101 g,nCfilLion**oh,n~o** {kw**hr~',.r) "H""pl,,~**  oy Ih,' inm,m,n'al ,",1"0 01"el,W;"i'y g<n"""Qn, "'LLmcd lo 00 SJ5.0Ui.\III'·hr. _\11 00" ligUle' i" 20m; dolld". E,lIm'lod AnIlLl.1 CJ,,,,,g" i" Un]1 C,mralion Dne 10 ·\PC Nth Eqnipmont Auili.c.v Pone, Electcicil]' Oom."d "lid G,ner"tion R,dlloli"n M'C TOlol Unil Tot.! Ulli! Elmric.1 Unit Electric.l Powor Illee,";c.1 Po"ec

Poner Generalinn Genec.lion Geoeratinn ,\lI. U,ago'"

### ROdlltl::,:~'**Cban~e'"** Chonge**Co,~"** Lllbotl"**NO~** Cnntrol Tecl'niq". klV_b"!vc kW·hrs! r kW hr'!I'r IOOO$!vr 

# , SNCR wi ASOFA 1,008.774 110,176,0'15**111,1~4,869** J.891 

# " (los Rchllrn 

### wi ASOFA (1,724.423) &1,4[6590 79,692.162**2.7~9** 

# , CoallU:burn wi ASOFA .19.217,554 IJO,3J5,506 189,59J,059 6,636 

# , rLGR wi ASOFA (949,05 I)**~1,910,02A ~O.9()O,9n** **Z,~3.1** A Adv.need SOFA{ASOFA) 7,664**75,R59.~55** 75,867,:;20 2,6:;5



## .

Bum, & MoDO<ll,dl C.1_IOArPENDIXCJ O&M CoS! Esiimale, NOx BACT An"ly.,j, SlUdy Revised 10/1712006 

### TABLE C.3-5
- Expllcled NOx Reagent Usage and Cost Estimates for MRY Unit 2 NOll. Controls·**NO~** ReduClioo NO. Redo<lion Reagen' Urea U,agel " Rcogont**D11~liDn** Watcr UsagelJ) All. Lobelll) N01 Conlrol T""llIIlque lbslhr lonsl -r 10OO'l:lvr 1000 

# "" , 1000S! 

# , 

# , SNCR 

### wi ASOFA 2.7\3 10,276 J,898 9,M51 

# " (1) AlLerI'""VO dos'gnauon ha, oeeo pre.,ously "-',,go,d [rom 10

... romo.,i to hLghesl removal**pe"'eJl,"~e.** (2)

- All "OS[ flgol"OS i" 2006 doll,,,. (J)

_**Re.~O"'** dilUli"" ""'''', ""<aBo ""Umo. p"\>oble wnlO[;' add,d '0 ereaLe. 10% "reo co1\O,",,,[io. (4 p,rts WOlO[ 10 1 pall ureo ,",,1;0" ,I 50% ,""","'",Iion) prio, '0 injoo'ioJL OilUlio" '"''''' uni, "." ",,",oed '0 be SI.OO ror Lho"-",ndg>Jlon'.


### TABLE C.3-6
- Expected Heat Input and Equivalent Coal Cost to Evapqrate Aqueous Urea for MRY Unit 2 NOll. Controls

() g p 

### y g 0 

### r s (2)

- H"l ""lU;n:<! '" <"!'O,,,'eun:, ""gonl d;i",ion ,",te, "",urn", 900 BLnllo ""luin:<! h,,-,ed "" , too/, "",a con,cn'",!;on (4 p.rt, ,",lor 10 ] p,rturea ,olu';on ,,50% ,00,e"',,,I;oo) ;njoc"'d [0' the ,..,litnoreJ amOu"1 of u,e, "sage. Co,]he" coote"l of6,662 !lrulln. uoit <OS! oUO.71ImmBlu. [,timOled ADnuol Average Unit Equinlent Co.l Con'umption Co,t rorA ucous Veea Ev. ocati." no.1 Rcquieed to ['1ui"al.ul Co.1 E,'aporate Consumption ror Cool Co",umption 

# '" Aqueous Vre.Pl
, He"dll"puf", Cu,II') Label'" NOx Coolrol Techuique mmDlul r Too,;", IOOOS/;e 

# , SNCR \\'1 ASOFA 7J,986 5,55J 

# "



# , AII,m,';vo d",j o'l;on nos boo" rcviou,[ ,,,; nod from ic",l n:mo"'] '0hi"",,, ",mo",' 

# or,,,,,,,. e**,~** 

# '"

Square !lulle Elcctrio Cooperali"e eJ_[ I D",m &**M~Duuncll**NOx B'\cr 

### ,\nolysi. Study
Appendix 

### C**Rcfcrcllce~:** APPENDIX CJ 

### O&M Cost E"imales

i 

### EPA Ofljce ofAir Qurrlily Planning and Slandards (OAQPS) publioation EPA/452iJ3·02·00 

### 1, Section 4.1, 

### NOx Controls

- 

### NOx POIll-Combuslion, Chapter 

### I _SelectIve Non-CataI}1ic Reduction, (bled October 2000, posted at their websile:**hltp:ffwww.q)u.gov/ltnl9!!~4j~\ks'l-Ld)l2df,** 

### Chapltt 2- Scle<:Live Calalytic Reduction, daled Oclobcr 2000, pO'le<!"l lhL>ir websile; http://www.epa.gov/tln!ealdclirljcs4-2ch2.pM.
;; ·'Stalionary Source NO" 

### ;md I'M 

### Emissions io lJ1e WRAP Region: 

### An Initial Assessment ofEmi,sions, Controls. ami Air Quality Impacts", October I, 

### 200] Western Regional Air Partnership Final Repon of the WRAP MarkdTradingForum, Section 

### VI: SUIIIIIIDIY of-Emission Controls Available for Large Stationary Sources ofNO

### x ancl PM (by Reaction EngiLleering In1ernalional), available at hltp:/Il"ww.WInD

### air.om 1

### for,-!mf<1Lnl(lnO}(-pm.hlm!
i, 

### "Analysis ofComb

### uslion Controls for Reducing NO" Emissions From Coal-fIred EGU's in 

### the WRAP Regiun" WRAP Draft Repon: EGR ContraolNumber 30204-101, prepared by Easlern Research Group, Inc., dated April 26, 2005, po,ted at theirwebsite: bttp-lIwww.wralli!ir&rWforllInsls'i**(I,loeument~ei.ctlsINOxEGUl050426Coal** 

### fired%20EGUs in 

### "WRAP Region-mart.pdf

• "Combustion Modification 

### -1m Eoonomic Alternative 

### tor BOller NOx 

### Control" GER-4192 (04/01), Folsom, Bluir A, Tyson, Thomas J_ 

### GE Pow"" SyslolIl5, Schenectady, NY, (1001) poslerl al their websi",:**hn~:lj~'Y.~p'oweL·.comlm'ocl scrv.'pro(!.u~eJs!Iecb** **dQcs/enJdownload&lger~** 

### 192,udf "; "Assessment ofConlrol Technology Optiom for BART-Eligible Source" Steam Eleelno Boilers, Imluslrial Boilers, Cement Plants and Paper rmcl Pulp Facilities", dated March 2005, posted aL**~leir** 

### website:**http://bron~~_ne,oaLlm.** 

### orgkommitIee.e1ha:zeffiART Contl'DI 

### AssessmenI.]oj

### f**~;** 

### Budgetary Proposal, Fuel Tech, InD. NO"OlJT" SNCK and SNCIUFLGR'" Systems, for One 450 MW 

### cyclone-fired unit, date,] December 9, 

### 1004.

Durll-' & 

### McDunIlell C3_12 

### Square Butte Eleclric Couporoliu¢

# gij
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