JOHN W. REGAN, PROJECT DIRECTOR RICHARD W. BORIO

MARKPALKES ABB POWER PLANT LABORATORIES

MARKD. MIROLLI ABB CE SYSTEMS

COMBUSTION ENGINEERING, INC.

JAMES D. WESNOR ABB ENVIRONMENTAL SYSTEMS

DAVID J. BENDER RAYTHEON ENGINEERS & CONSTRUCTORS, INC.

Contract NO.: DE-AC22-92PC92159

In response to challeages from technologies such as IGCC and PFBC, the ABB LEBS Team has proposed removing the barriets to vay large advpnces in environmental and thermal performance of pulveriLed cual plmts. Pulverized coal willcontinue to bethe sourceof more than half of our electric geaerptioawell into thenext century and we must develop low-risk I o w a advances that will compete with the claimed performance of dhet technologies. This paper describes near-tenn PC techndogies for new md retrofit applications which wiU accomplish this.

INTRODUCTION

Since the inception of the 'Engineering Development of A d v d Coat-Fired LOw-EmisSion Bok Systems' contract (LEBS) the aggressive emissions targets have been gradually tightened and the efficieacy target gradually raised in response to pressure from s e v d directions. Tbe contract targets for emissioas rn now pppro-y one-half of the original values for N&, S& and particulates and the efticieacy target has been raised substantially - 38% to 42% (HKV, net). The ABB Team believes it would not be difficult to reduce the emissions by one-half again and to raise tbe efficiency target another 3 4 percentage points, and it proposes to do 90.

LEBS is restr id topdveriLedd firing (PC)~I&Aisviewed by m y ~ l ~ g l ~ ~ h o t h e r d - f i r e d technologies such as IGCC and PFBC, most likely k a u s of the x n i s c a ~ o n that PC! with tbe Rankine steam cycle has neared its limits of efficiency d emissions performance. In truth, thete is cwsideroMe morn for cost- effective improvements. The path to these improvements is defined and is short. The required development effort is not great and the result will be low-risk low& fimibu-looking systems which will be readily sccepted by the very conservative, risk-averse utility industry. The technologies descn'bed below are fixel-flexible d suited to retrofit, repowering ana new ppplicatione.

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SUBSYSEM TECFINOLOGIES TO ACHIEVE PERFORMANCE

In-furnace N& Control

The objective of ABB's in-thmce NO, reduction process is to reduce nitrogen oxides kpvino the prixrmry furnace to 0.1 lb N&MM Btu (75 ppm @ 3% @)or lowet while maintaining an accept&e level of carbon in the fly ash. (Further N4, reduction can be rchieved with the downstrepm SN*- pro~ear which is &scud betow.)

Tbe process for evaluating the vxrious firing system ~ W & g u d o n s which ,+BB has formulated invdves the use of computational modeling, small d e experimental testing d hqez d e experimezltnl testing. Additionnlly, it has involved coacurrent charoctenza * tion of d pulveritation in an ABB-&velopea pulverirpt with x dynamic classifier. As N4, levels are pushed ever l o w it is imperPtive that the fuel @de Sizs distribution also be more tightly specified as a primary means of contrdling ambus t i i e losses. Figure 1 is a flowchart showing &e interPCtion of the various dvi t ies descn'bcd above, tbe prbxuy delivexable being input into the revised system design. The FSBF refexred to in Figure 1 is a Fundpmentnl M e Burner Facility iad the BSF is an 80 million Btumt Boiler Simulation FtciIity.

The two primary activities whichwill bepddressed in this paper arcpreliminary results fmmtesting in the FundruneotPl Scale Burner Facility (FSBF) and chmtmmh 'on of me of tbe LEBS cad.s in ABB's PulveriZet Devdopmeat Facility. Computational modeling is undenvay pad will be ddtessed briefly.

Comutational Modeling: Two models are being employed to help a n a l p tELa various firing systems concepb that have been formulated. A kinetics &on d, C H E W , is being used to pmVide a prdiminary evaluation of the potentid for various concepts to achieve the desired results. It is recognited that results from this evduation are qualitative at best ami can d y beused to providetrds; nevathekss its use canbean important screening tool to help prioritize the most promising concepts for furtbez evaluation. A comgutathd fluid dynamics model, FLUENT, is being used to further evaluate colloept8 rmdez cwditions which bettet simulate actual boiler opedon. Unlike C H E W which isslrmes ather wtllattrad reactor conditions or perf& plug flow conditions, FLUENT is able to simulate r e a l - d miXing Coaditbm. ABB's huge combustion hility, the Boiler Simulation Facility @SF) has been modeled with FLUENT. Experimeatal r m m m m t s fromthe BSF compare quite well with thosepredicted by FLUENT, namelypmmebm sucb as gas hprahms ond gaseous conceatrations like 0, and CO. Hxving validated FLUENT with BSF dah, the intent is to use it a well as the CHEMKIN model in ways tbat c a p i t d k on their redpectve stzengths to evaluate and s c m various firing system c o w .

Fundamental Scale Burner Facility (FSBF): The LEBS plan calls for evaluation of a d v d coal reburning as a supplemental NO, reduction technology. Rebuming is classically thought of as a m, downstream (from the primary combustor) m e into which 'rebum fuel' is injecten followed by a 'burwut xmc' whete air is injectad

' '~Vebpmeat of ABB CE'r Tangential Firing System 2ooo" preseated at the '93 EPA/EpRI NO, confereaoa

BSF TEST #2 #

re 7 - Schemm d Fundamental Scab Burner Fad&

to burn out the remPining cornbustiiks from the reburn zone, which typically operates at substoichiometriC conditions. Rcburnhg in the c l d d sease has been shown to be an effactive tclchwlogy for reducing NG; however, wheauscd in the t radi t id fpshiw greatez residence time is needed in the separak raburnd burnout zone8. However, N4 , reduction through the rebum@ pnxxss can and does occut within the primnry combustor. Tbc objective of testing in the FSBF has baeo to chnrrctenre theN4(mdcombustionpafo-fromfiring system concepa which do not hive thectpssicrl, sepacoterebum ad burnout ~ ~ e b , M d~~whichemgloy integrated Strpteoies within the main windbox zone that take dvantage of N4( reduction though rebum process chemistry. The rdvantagea M less r e s i h time, smaller furnrca a d a tovorobfe cost imp4ci. It is believed that tangentiat firing, specifidy buildiq upoa the alreadycstnblished TFS 2000'''' system, is wcu suited for adaptation to theintegrated ~ s y s t e m c o a c e p c .

The Fundamentil Scale Bumer Facility (FSBF) is a horizwtplly fired experimeatal combustor which has a capacity of5 million Btu/hr. SeeFip2. It has bees Conti@ to simulotetangeatirl firing; airand M are injected from four noales for each plane, or elevation, the team used to hi a plane in a tnngential firing system. As nded in Figure2 there area number of planes fiomwhich fid or air caabe injected tosimulate and evaluate a particular firing arrangemeat. Additionally t6ere are air-cmly injecfors downstrepm of tbe main windbox to simulate over fire air inject;m

Low N4( firing geoerally requires that themain windbox or burner m e b e tired unda arbsbichiometric conditions. Table 1 shows the relative NOx values as a function of bulk stoichiometry ~JI the main wiadbox mnc as simulatsl in the FSBF. configuration 1 represeats a bpse case where dl of the combustion air is injected through the main windbox; the N G level is rubitnuily shown as 100%. configurations 2 ond 3 show relative N4, values for arbsbichiometric firing in the mnin wiadbox and with diffexed pmounts of seoprated Over Fin Air (SOFA) in SOFA levels 1 and 2. As expected, substoichiornetric o@oa d t s in lower NO, and the strategy for staging the SOFA also makes a diffetenoe in the final N4( levels.

Table 1. Relative N G Lev& vs. Main Blrmer Zone Stoichimetry (MBZ) and Separated Over Fm Air (SOFA)

CoIlfigulXtiOZl 1 2 3

N&%* 100 66 54

MBZ s t o a 1.15 0.8 0.8

SOFA 1 Stoich SOFA 2 Stoich 1.15 1.15 1.0 1.15 0.8 1.15

*Normnlited, with Case 1 assigned 100%

Initial testing in the FSBF was designed to evaluate a number of variables Within the main firing m, including firing system configuration and operating COELditio~is, for their effect 011 NOW. Table 2 shows some initial results from a number of firing system dgurotions, so= of which employ integxxkd !iring system strategy. Relative to the base case, configurations 4 and 5 an run toproduceIowN4(without thew of SOFA, while configurations 6 and 7 show relative N4( levels with the use of SOFA.

TabIe 2. Relative N4; Levels for Integrated F- Configurations YS. Basecase (Confi i t ion 1)

contigurption 1 4 5

7 6 .

N4,%* 100 64 59 54 49

MBZ stoich 1.15 1.15 1.15 0.8 0.8

SOFA 1 Stoich SOFA 2 Stoich 1.15 1.15 1.15 1.15 1.15 1.15 0.8 1.15 0.8 1.15

*Normalized, with Case 1 assigned 100%

Testing in tho FSBF is continuing; plana under our LEBS Program ull for Continued evduptiOn of firing system concepts that uc hypdbesizsn to produceever lowcrN4( levels while Meting our goal ofmpinhinbg combustible losses rt minimum levels.

: As nded above, spacificcltion and coatrol of d @cle s i z ~ distn'bution is M important 1 hlvenzahop pretsqUisite for wrcctssful o p t i o n of i low N& firing system. coaditions for achieving low NO, tend to run cwnter to those that on Favorable for good coal oombustioa; thetein lies the W e a g e . Paying atteation to the proper coal particle size distribution hss the obvious effect of facilitating better carbon bumout pnd the perhape not-soobvious effect of errhancig N4( reduction through earlier release of nitrogea species in the near- mne where the opportunity for oonversioa to moleculnr nitrogen is incteosed.

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ABB has cumhded i Pulverizer Developmeat Facility (PDF) for tbe sady and chuwhmh * ' o a o f d pulverization Md classification. Tbe PDF includes i Coat storage and feed system d a fine coal oollectiotl system 8% necessary support quipmeat for the pulvefizer itself. The mill regreseats a comm~cial design, based OIL i si23323 bowl mill, but with the flexibility to change out importantcompooeatswifhinthemill, suchas grinding elerneats ind chssifiets. Tbe @ty of the PDF is rrbwt 3.5 tondhr.

The eady focus of the LEBS-related work which utitizeS &e PDF bns kea to c b a c k r m tbecoalpslrticze~ distribution and mill power requirements. Ideally it is desired thst the top Site of the d particle8 be dosely controlled and that classificatim is more efficiedy carried out so that sufficidy fine particles are not tecirculated needlessly back to the gfinding zone of the mill. The use of i dynamic classifiex is one way of nccomplishiagthis.

Table 3 shows results from Fecent testing with various dynamic classifier designs as compared with a base case static classifier design. It is appareat that the goals of greatex 4 fbeaess, less coarse material md lower powex reQuirements have all b e a achieved with at least two'of the dynamic classifier designs. Results have beea demonstrated with coaven t i~d akooal ratios, namely 1.5 lb air/% 4.

Future testing in the FSBF will employ the use of coals having various particle Size distn'butions to iscertarn *sod quantify the benefits of using finer d.

Table 3. Dynamic CIaSsitier C h a r a m t i o n

static Dvnamic Classifier Desieaation Classifier .HP1 HP2 -1 RB2

Product size (wt%) +so mesh +lOOmeSh -200 mesh

0.1 0.2 . 0.0 0.0 0.0 2.4 1.2 0.6 0.5 0.6 84.3 85.7 92.7 93.1 90.7

Relative Power Requirements (%) 100 81 98 97 107

Stack NOx, S&, Particulates and Title IIIPollutants

General DescriDtion of Control T e d ~ n o l o ~ . Boiler outlet emissions will be controlled by a modified SN&m process, referred to as the SN&m Hot Scheme. The SNGm pmcess which simultaneously removes nitrogen oxides and sulfur oxides fiom flue gases, is a licensed technology developed by Haldor/ropsee M, Denmark. Thc SN&m technology has been demonstrated in several forms, one as a Clean Chal Techwlogy at Ohio Edison's Niles Station, and has been constructed and operated on a commerdal scale in Denmark. Tbt SNoxTy techwlogy consists of five key process areas: particulate collection, N& reduction, widation, sulfuric acid condensation, and acid conditioning. For the LEBS process, tbt particulate collection and I+& reduction proces are integrated into a single process step.

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ParticulatciNOx Control: The first step, particulate collection, will have a direct sect on tbe p ~ f o r m i h x oftbe downstream S Q converttr, particularly the frequmy ofcleaning the sol a t a l y s ~ Tbis is due to tbe inberent abiity of the catalyst to retain greater than W ? ofall particulate matter which enters tbe converter. Tbe collection ofthis particulate matter, overtime, will cause tbegas draft lass to increase. "kvirgindraft loss can, bowevet,be restored through catalyst cleaning called screening. Higber dust loads at tbe S& convertor inlet therefore require more frequent cleaning, and higber catatyst attrition loses. A target dust level of0.0008-0.0016 lb/MMBtu (1-2 mgMm3) leaving the collector is desked. ConsequentIy, dust emissions from tbc S& convertor are oftcn an order dmagnitude lower.'

To achieve the required particulate loadings at the SOz converter inlet, a high efficiency collection device must be employed. FortheLEBS~,aceramicfilttrmanutacbredbyCtraMemwillbtemplaytd

The constnrdion of the ceramic filter is based on the use of porous honeycomb ceramic monoliths. These high surfice am, low ast materiats were developed for, and are widely used as, supports. The monoliths havt many cells or passageways which extend fro maninlet face to anopposingoutlefface. Cell stmdureisusualty quare and cell density can vary from 25 to 1400 cells per square inch (cpi) 0th area Mean pore size can range fiom 4 to 50 microns.

Thc superior properties of commercially available monoliths make them ideally suited for applications requiring high thermal stability, mechanical strength, and corrosion resistance . These rigid ceramics have been used for years as N& SCR catalyst supports in combustion flue gas applications. Tbe monolith stmctwe used for cataljst support material is readily adapted to fundion as apartiahtefilter. The monolith stnrcture is moditiedby plugging every other cell at the upstrtam face with a high-teqrature inorganic cement Cells which are open at tbe upstream face ofthe monolith are plugged at the downstream face. Flue gas is thereby constrained to flow through porous cell walls, and at appropriate intervals, the filter is clean4 bybadpdse air.

CeraMem has developed the technology for applying thin ceramic membrane coatings to the monoliths ad controlling the pore size. TIE thin (approximately 50 microns) membrane coating has a pore size approxhkly 100-fold finer than that of the monolith support. Thus the filter retention efficiency is determined by the membrane pore size, wt the monolith pore size. The ceramic filter will operate as an absolute filteq that is all particulate over a certain diameter willbe removed fiomthegas stream. Tbt split diameter is determined and controlled by the ceramic application.

In the L D S process, commexia~y~ested otber low dust SCR applications, concerns h t flyash poisoning ofthe catalyst are e h h b d , and atalyst loadings maybe reduced as the caw will havea"highe?' activity. Also, in this application, tbe reaction kinetics will nd be controlled by mass diffusion as in other monolith applications. Instead, tht kinetics wilJ bt much Wer , taking advantage of Y d diffusion", where the flue gas will come into forced amtact with tbe catalystasitpassesthroughthemonolithwall. Athirdbe~tofthistechwlogyinrelationtoSCRperfonnanct will come about fiom elevated conversion temperatun. Typical SCR applications operate at about 675"F, wfiereas the L.EBS application will operate at a slightly higher temperature of 750-775OF. Irmreased temperature should not affect catalyst lit% but should improve the efficiency of tHe reducing reagent, in this case ammonia. The increaSt in temperature should result in a lower ammonia concentrations at the SCR outlet, &en called slip.

Particulate and NOx Emissions Levels: Taking advantage of the clean-side catalya application, forced &ion kinetics, and higher reduction temperature should allow for much higher reduction efficiencies and efficient reducing reagent consumption. Early data indicate that at N4( inlet concentrations of200 ppm, N4( reduction sbould exceed 90% without any measurable ammonia slip.

catatyst is applied to the clean side oftbe particulate filter. As nith

* These Iwels are below normal detection limits ofEPA Method 5 sampling The method collection time would bave to be extended to be able to detect these emissions.

Sa Control: sol emissions are controlled by the conditioning system. An oxidation catalyst, which is widely used in the s d f d c acid w, ConVQts the SO2 to So, at greater than W/r a a e n c y . The &ciencyofthe catalyst is mt affixkdbypresebct afwater~poro~ chlorides in concentrations up to 50?4 and s e v d hundred ppm, mpxtkdy. An additional kn&t oftbe s u h k acid catalyst is its ability to oxidize carbon monoxide ami hydroarbom present in tbe flue gas stream to hoamus compounds.

oxidation catalyst, sdfuric acid condensers, and acid

Tbc SO3 in the & a ~ leaving t h ~ Qco~lvertefis hydrated andcondenstd in two- First, tbebdkdtbeS4 ir hydrated to rmlfirric acidvaparas the flk gas passes thfoughthtLjun@rom air heater and tht tempatmdrops to approximately J O O O F . At this point, the flue gas is still well above tbe acid dewpint, thus avoidingd condensation and corrosion aftbe ductwork The flue gas then enters tbc WSA coaderrsa, a Unique tube and shell fslling film condenser withtheboiier combustion air used as a cooling medium on tbt shell side. Bmdkate @ass tubes are used to convey and ml the fluegas. Inboth steps, the hydrationandcondensation reacti(H1s are cxothennic, thereby adding heat to the flue gas and subsequently to tbc boiler tbamal systtra 7% design and operation of the WSA Condenser make possible virtually complete condensation and captun uftbe sulfuric acid at concentrations of 92 to 95 wt Yh

SO, Emissions &IS: TO this point, SN&m systems have not been built nith !X& rtxmd efficiencies of greater than 9S%, and therefore, data otber than that obtained at laboratoryscakwdd bot support the ability to achieve higher rem& efficiencies. However, ultra-high removal efficiencies (typicalfy greater than 98%) havc been studied by Haldor/rbpsoe, with the information being used to design, build, and opehate highdw systems. As this is a catalytic system, remod efliciency is fix& and somewhat influable. Ea syskm is designed for a specific rem& efficiency, it will maintain that degree afcontrd over a wide operating range without any & o m unlike chemical reagent systems which tend to become @dc Wed and lose removal capibility as inlet levels decrease. Increasing remoyal efficienq would rOqnin minor moditication dtk convertor vessel with catalyst addition.

So, emissions will be controlled by the efficient condensation system, in excess d 999% condensation However, some SO, will pass through thesystemandwill exit thestack, and it is expcta3thattbiSamount wouldnotbein excess of 20 ppm - a level similar to emissions from presentday wet or dry

Title Ill Pollutants: The Niles demonstration facility was sampled as part af tk DOE/EpA Fidd Chemical Emissions Monitoring. It was found that the S N h m technology was able to reduot Ti III me4a.I unissions by greater than98% and Title III organic compounds were not detecled at Sign&ant lazk The COmmmS d e facilityinDeMlarkwas also sunpledby an independent team, with the results reportedaM6rmingthOsedAahed from the Niles sampling.

- ‘onsystems.

ImDroved The& Efficiem Heat addition, transfer, and recovery are ufsignSca.nt impOrtance in the SNoxTy process. The process generates recoverable heat in wed ways. AU ofthe d o n s which take place with rwpect to N& and SO, removal are exothermic and inc~ease the temperature ofthe floe gas. This heat is recovered in tbe air heater and WSA Condenser for use in the fiunace as combustion air. Became the WSA condenser lowers the temperature ofthe nue gas to about 2100~, compared to the 3000~ range fix wet a ~ d dry d, additloaal sensible heat is nxxlvered dong with that from the heats ufreaction In comparison to an N S m m plant, 38% more heat is recovered from the flue gas stream after theboiler, itselfauxmtmg - fora 1.9percentagepoint increase in the net plant thermal efficiency.

’ Although stack temperatures for wet and dry FGD systems range from 12S-w)oF, heat ncovery - tbat doneby the air heater - usUay.is limited to a minimum temperature of300OF. After that, the flue &as is quede4 accounting for the temperature dii€erem.

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Wute and Byproducta

As shown inTable 4, unlike many otherprocesses, the S N O p process Qes Dot gtDMate a waste product or intermediate. Also, the SNhm process does not produce a "commCIcial grade" product which docs not mcd the spxScations at its intended market, as has ticen tbc case with Wet FGD gypsum The sulfuric acid produad by the SNGW process, a typical analysis of which is p a n t e d in Table 5, meds or exceeds US. Federal Specification 0-S-801E Class 1 and is commercially tradable without limitatioa

Tbl ABB project team includes, as an advisor, Peridot Chemicals. Pcridot chemicals operates two sulfuric acid production facitities and distriiutes acid from several international involuntary acid producers. Peridd chemicals has providedvery usetul insight into tbe dowstic futfuricadd market.

htallation of a SN&W ficility, or any large acid production facility, wiU Eorct a reshaping Qftk local acid market, and alliances ddbemadewithlocalbrokerr, suppliers, andconsumtrsfordistnbutionandconsUmption ofthe acid. It isbelievedby sutfuric acid market experts that domestic iwoluntaryacidproductioncdd displace international involuntary acid production,

It is e@ that the flyash from the LEBS -ern could be sold commerCiayt, similar to present day ash disposal. Carbon content in the flyash is expected tobe less than5%, and there is ndexpeded to be any noticeable prknce of ammonia.

Table 4. End product and disposition by technology.

Technological Advancement Product and Disposition, Coot C o m p a h

1st Generation Technology - consumable reagent processes, usually sodium- or calcium-based, such as

furnace injection, and duct injection.

Landfill afsulfite/sulf8tt compounds with link cammercial or W value. Calcium sultate from M F G D -beupgraded to CommerCial-grSdc gvps~m, but at significant cost Low capital cost, o f k t by high OgrMcOst

luwhmtone Wet FGD, lime Dry FGD, limestone . .

2nd Generation Technology - regenerable reagent processes, such as W andMg0 systems.

3rd Generation Technology - catalytic (no reagent) technologies, such as SNGmprocess. .

Prodoceschemicalin~ate,usuallymebllicsulfi&

cap i ta lcos tand~cos t

or sulfite, which rrmst be landfilled or further processed to produce sulfiuic acid of elemental sulfur. High

Direct production ofelemental s u l h or sulfuric acid. High capital cost, o€kt by low OBiM cost.

On whole, it is expected that the amount of kmEli material from an NSPScompliant phnt (Esp/limesbne WFGD) will be reduced by approximately S5%, expressed on a heat input basis This figure accounts for the FGD by-produa, a wet mixture ofcalcium sulfite and calcium mlfhte, being bndfilled as oppasd to the S N O P product, commercial grade sulfuric acid, being sold For every ton of sulfur in coal, 7.7 tons ofbndfitl waste has been converted to 3.3 tons of sulfkic acid. With aaluations of SlS per ton landfill and S30 per ton commercial grade acid, a net swing of S214 is created, from axi outlay of Sl15 for kmifill costs to an income of S99 from acid sales (exprpressed on per ton S in coal his). Comparing disposal for tbe LEBS SNoxn' design to a ~ I Y FGDHabric filter system wwld yield a differential ofS164 in tavor of the SNoxTy plant, primady in the reduction of landfill costs assoCiatedwith adrywaste. & a acid price ofS20 perton, it is expededthatthe air pollution control system wwld operate at a finaacial break- position.

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Table 5, Federal Specification For Commercial Grade Sulfuric Acid and Actual Acld Analysis from Operatlng Unit

Federal Specification Maximum Valuer

93.2

50 50 40 1 1

20 1 0.2

10 10

Water Clarity, Now

Typical Vduea tmrn Operating Unit

94.76 ND

3.4 0.025 0.12 0.012

4.002 26

0.04 0.065 2.9 ND

HIGH EFFICIENCY POWER CYCLES

Llve steam temperature & reheat temperature

Heat Rate Improvements with Stngle Reheat TurbIne

Uve steam temperature & reheat temperature

Heat Rate Improvements with Double Reheat Tuhine

PROOF-OF-CONCEI" TEST FACJLlTY

If Ibe ABB Team is selected to execute PhasalV of the LEBS Project, a435 miIlion Btu/hrsystem(d and flue

Power &Light - Whitewrtet Valley Unit 1. Since the txiSting turbindgtxxdcx and nwst of the b o k and infnstnrchue may be retpined, it may not be possible to demonstrote an dvanced cycle. However, the system

emission oontrql techaologies, operability and reliabiity of a compIete geaqatbg system in full commercial Senice, thc integration (air, gas and water) of the SN%"' bot p m with tk boiler system md hubine/geneFPtor,the quality of the byprodud sulfuric acid, etc.

gas flow aquivdent to 50 W e n e t @ 42% efficiency) will be c a s h c k d as a r q o w c i q dRichm>od (Indipnr)

will be in commercial servig during thesix months of testing which will permit cOaCtu.sivedemo&nh 'onof: all

Tbe major items of equipment that wil l be installed are:

Complete Firing System (feeders, pulverizers, burners, air supply, burner -emeat system) and

Complete SNG' Hot Process including ammomat * urea injection, calalytk filter, S% reador, acid cmdemx, acid and rsb stoTPge and hnndling. Gas bypass to maintain desired gas temperaue to the SN%=HotproceSa Air-to€.mdWHeatEx~ertoru~te~feedwaterheoter.

Clean gas ductwork to theexisting stsck. Boiler P o d Draft Fan rad Drive. Induced Draft Fan md Drive. Hot air ductwork to the boiler. Distnited Contrd System. Diagnostic Devices. Required BOP, demolition, civil and structural work to provide a complete Operotiag plant.

nquired boiler d f i d o n s .

G8s-to-Airheatwrchnngez.

Tbe existing boiler's air heater and tssociated ductwork will be removed.

The truevdue of theLEBS Project lies iu @testing and commercinl operation of a m of suf€icieat ccrpacity to convince the markets that LEBS regreseata knkisk technologies. This is thcooly surepath to the overall objective of expedited commetsiahtion.

A COhihiERCIAL GENERATING UNIT DESIGN

In Phase I of the Project each contractor produced the prdiminary design of a commercial genaating unit (CGU). The ABB Team's 400 W e CGU illustrated in Figure 4 is an adaptation of a c o n v a t i d pulverized coal-fired steamelectric plant. It will becompared to a Koliap design undeta Sepprrtework effort. For each Besign

= .

selected tschnologie4 have bee0 introduced to tchicw reduced levels of emissions, iocreosed tbermnl efficieacy, reduced wlstc and improved costs. Thesa techdogie8 involva primnrily thna U u S :

This combinatim of emission control processes meets or bettenr dl of tbe target a n i d lev& for the LEBS Project, while produci eilbet beuign 01 saleable by-products from the gas treatmat. 'Ibe advanced cycle and the SN%w Hot procesS a b l e the design to meet the efficiency objective and, idredly, the cost of electricity objective.

NSPS LEBS PLANT CGU

lb/mm Btu* 0.60 0.10 Ib/mm Btu 0.60 0.02

S%

Particulate, lblmm Btu* 0.030 0.002 N%

Net Efficiency 0, % 35.4 45 Tdal Waste, LBkWh 0.352 0.117

* 3 Ib S and 15.4T-J~ ash per millionBtu in the coal.

Volatile organic emissions, CO and ammonia slip will be oxidized in the S@ oxidizer nnd there will be no visible stack plum. The CGU produces significantly less waste than the NSPS plant. Par2 of this is due to the l o w mount of ash produced pet kwh because of the higher efficieacy cycle and t& SNOXTW Hot Process. 'Ihe major portion of this reduction results from the production of sulfuric acid as a commetci.lly salede by-product &er than the sludge normally genecoted by an FGD system. Tha plant use6 a 5500 pdg, 1HX)OF arperCriticd thermodynamic cycle with two reheat streams. The g r c s output of the generotor is 468 Mwe pnd the net plant output is 445 W e .

Tbe CGUhas a total plant cost that is less than thepwtof a current NSPS plant. laeW capital reqimnmts estimate includes the time related portions of tbe project estimate such as dowpmx for funds used during

coaoept of 8 'Consortium' formed to produce a numbex of these units rn 8 replicated and m0ddafhe.d basis. These factors, coupled with ABB's commitment to a Significantly reduced 'cyde time' for the boiler and other key equipment results in significantly reduced schedule from award to start-up. This w i v e conshction

txmbwtion. Tbe improvements come from the adoption of an aggressive co- 'on plan that utilizes the

scheduleimprovesthetime-related~.

'Ih CGU wil l satisfy the objective of having a cost of electricity equal to or lesi than that for the NSPS plant. The calculated cogt of electricity is reduced by the by-product credit received from t& sale of the sulfuric scid (using 8 figure coafirmed by an outside market study) and by an aggressive but achievable cagat5ty factor. An independent reliability, availability and maintainabiity analysis was completed for the CGU. 'Ibe +uIy was based on performance data obtained from the NERC data base and utilized the indw accepted 'Delphi' process to %the data for the CGU. One reason enhanced reliability a d equivalent availability are achieved is that the SN& desulfurization procsses that utilize lime OT limestone. The simplet process, abseace of mechanical equipmeat, mi the passive charactet oftha process results in higher ;eliability and availability.

Hot procesS k 'passive', Le., it bas far less mechanical equipment than k typically found in flue gas

,

The design also incorporate8 advanced diagnosljcs concepts which provide early warning of impeading failurea in tbe plant equipment. This advanced knowledge has sevetll h f i t s that result in improved reliobity rod availability. Advanced diaguostics should amble mpinlennn~a outage8 to be both more effective by providing mahtmmce informatioa in mas which might not be readily d k t o inspaction, and shortexbecause prqwPtion will be- due to a dud numbez of 'surprisa' rrpPin.

Pinnlly, the CGUwill have good amss and -of mninta&cebecauscit was designed forgoodoccessmd case of constnrclioa. Tbeplant is hid out with tbe 'ranch' umcqt. This minimi@. Rrtber, it is spread out in thcboriz;ontp1 plane. Xndditioa, thepknt design incorporotesa 'baclrboaa' utility rack for piping, cable, cooduit and etsctrical wiring. The ground levd partion of this rack k Ud988- LCC~SG corridor that rune throughout tho plant. A b , e g piping md cooduit oa overhead racke provides more g d levd yscts~ to equipmeat for mninteawx. Incmpodng these feahuw in the design of tha plant, d coupling them with tb implementation of a 'design for maintnianbility' r P p d .during the detailed design stage, will result in a plant with supexior avpilobity and highex capacity foclor which help reduce the axit of electricity.

tht tberhckhg of e@pment b

CONCLUSIONS AND FWURJ3 WORK

~ l l of the foregoing are responsive to the technical, re~atory and &mic neecis of h power genetation industry. Tbe advanced performance of ABB's LEBS technologies coupled with efforts to minimize investor risk should makc it extremely attractive to the utilities Ilnd IPPs. The near tam character of tbe LEBS tachnologk chosen, coupled with the attractive performance and wst fahues of the ABB CGU, support a c o n f i h in the Project Team that the proposed CGU design will be rcceptableand marketable.

Testing at laboratory and pilot scale will be completed in Phase II. Phase III will Consist of updatiing the CGU and POCTP designs based oa the results of theworkcompIeted in PhPseII. In addition, the li&g of the POCAT will be completed and a M e d test plan will be writtea

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Acknowtuirtmnt: A large number of people representing the US D q a m m t sFEnag.r - Pittsburgh Enagy Technology CCrrJa, the authors' companies and ad*on tc? the projcu haw wntribrrted to the wrk d e s a in the paper. Any attempt to list all of their nrmtcj risks ominins one or more. Howwr , their wnnibrrtions an cicepfy appreciated and they are hereby aalsnawbdged and thanked s h a d y .

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