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# OAR Box 

# 1828
Prepped by Ollie Stewart



### Document

Number: 

# 320 ) IV-B-2 4
Docket Number: 

# A-83-2 7

Printed 11/12/2008 11:12:59 AM Sheet 320 of 325P. 2

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# A-83-2 7

CORPORATIO N IV-B-2 4

MEMORANDUM
DATE : Jun e 22 , 198 7 TO : Walt Stevenson , EPA/OAQPS/ESE D FROM : Davi dWhite , Radia nCorporatio n SUBJECT : SO - Reductio ninAdvance dCombustio nSystem s

Thi s mem o review s informatio nprovide db y representative s fro

m TAS , Inc . an dTRW , Inc . regardin g th e abilit y o f advance dburne r system s t o remov e SO durin g combustio no f coal . Th e objectiv e o f thes e discussion s wa s t o determin e 1 ) whethe r significan t SO - reduction s ar e possibl e an d2 ) th e commercia l statu s o f thes e technologies .

TA S Micronize dCoa l Syste m Informatio nonth e TA S micronize dcoa l mil l an dburne r wa s provide db y Mr . Dougla s Hunt , Easter nSale s Manage r fo r TAS . TA S i s a smal l engineerin g desig nan

dequipmen t fabricatio ncompany locate dinMagna , Utah . Wor konth e TA S micronize dcoa l system bega nin1978 . A

cop y o f th e TA S literatur e describin g th e system i s inth e Industria l Boile r S0 2 docket . Th e principl e part s o f th e TA S system ar e 1 ) a low-horsepowe r rotar y attritio nmil l reportedl y capabl e o f micronizin g coa l t o 8 0 percen t throug h 32 5 mes h(equa l t o roughl y 4 4 micro n[0.001 7 inches] ) i na singl e pas s (versu s 7 0 percen t throug h20 0 mes h[7 4 micron ; 0.002 9 inches ] fo r a conventiona l pulverize dcoa l system ) and2 ) a stage dcombustio nburner . Micronizin g th e coa l increase s particl e surfac e are a pe r uni t o f fue l b y 3 t o 5 time s relativ e t o pulverize dcoal . Th e increase dsurfac e are a an dsmalle r particl e siz e result s inhighe r fue l reactivit y an dincrease davailabilit y o f alkal i sorbent s i nth e coa l whic har e importan t t o in-sit ucaptur e o f sulfur . Anothe r benefi t o f micronizin g i s tha t th e smal l particle s o f as hforme d durin g combustio nflow aerodynamicall y

aroun dhea t exchang e tubes , thu s aviodin g problem s wit has hdeposition , reduce dhea t transfer , an dtub e erosion . TA S claim s tha t becaus e o f th e increase dreactivit y o f th e fuel ,

Progres s Center/320 0 E

. Chape l Hil l Rd./Nelso n Hwy./P.O

. Bo x13000/Researc h Triangl e Park

. N.C

. 27709/(919)541-910 0P. 3

the y ca noperat e th e primar y zon e o f th e burne r unde r stron g reducin g condition s (approximatel y 6 0 percen t o f stoichiometri c ai r requirements ) an d stil l achiev e rapi dan dcomplet e burnou t o f th e fue l inth e secondar y combustio nzone . Unde r thes e conditions , sulfu r inth e coa l ma y reac t wit halkali s i nth e coa l as ho r wit hinjecte dlimeston e t o for m sulfide s (e.g. , CaS ) rathe r tha n sulfate s (CaSO- Ja s woul doccu r ina mor e oxygen-ric hatmosphere . Similarly , nitroge ni nth e coa l ma y conver t t o N « rathe r tha nNO . TA S report s tha t substantia l sulfu r captur e (nea r 9 0 percent ) an dlow N O level s hav e bee n obtaine dwithou t additio no f lime o r limeston e durin g pilot-scal e tests . Th e existin g data , however , althoug hver y interesting , ar e to o limite dt o draw clea r conclusions . Mos t o f th e existin g TA S system s ar e bein g use do nkiln s an

dasphal t plants , rathe r tha nboilers . Th e firs t larg e coal-fire dboile r wa s recentl y constructe da t St . Loui s Universit y Hospita l i nSt . Louis , Missouri ; start-u p o f th e syste m

o nnatura l ga s occurre dthi s pas t winter . A s o f lat e April , testin g wit hcoa l hadbee nver y limited , du e inpar t t o hig hsurfac e moistur e i nth e coa l shippe dt o th e hospita l an dresultin g problem s wit hth e coa l handlin g syste m

upstream

o f TAS' s equipment . Th e hospita l i s schedule dt o perform anEPA complianc e tes t fo r th e loca l ai r agency inJun e durin g whic h S0 2 emission s wit hcoa l wer e t o b e measured . Thes e dat a coul dthe nb e use dt o estimat e percen t S0 2 captur e b y alkali s i nth e coa l as ha s wel l a s adde d limeston e o r lime . I talke dt o Mr . Hun t i nearl y Ma y andh e promise dt o send
m e a copy

o f th e complianc e tes t result s a s soo na s i t i s available . I hav e no t receive danythin g t o date , however . Base do nth e availabl e data , th e TA S system appear s t o be a promisin g metho dfo r reducin g emission s fro m industria l boilers , bu t to o littl e dat a ar e currentl y

availabl e t o documen t it s actua l performance .

TR W Slaggin g Combusto r Th e TR W slaggin g combusto r use s conventiona l pulverize dcoa l combine d wit ha stage dcombustor . TR W i s a majo r technolog y developmen t compan y i nth e U . S . A descriptio no f th e TR W system i s inth e Industria l Boile r S0 ? 2 docket .P. 4

Th e combustor' s firs t stag e operate s a s a small-scal e gasifie r i n whic h th e coa l i s converte d t o carbo n monoxid e and hydrogen
. Th e TRW syste mi s simila r t o th e TA S syste m i n tha t bot hoperat e th e firs t stag e unde r stron g reducin g conditions

. Temperature s i n thi s sectio n ar e sufficien t t o conver t
mos t o f th e as ht o slag
. Astron g swir l cause d b yadditio n o f ai r an

d fue l tangentia l t o th e combusto r axi s impart s centrifuga l forc e o n th e slag
. A s a result , roughl y9 0 percen t o f th e sla g deposit s o n th e combusto r wall s and flow s dow n t o a ta p hole
. Th e "de-ashed " combustio n gase s the n flo wt o a secon d stag e wher e additiona l ai r i s adde d t o complet e combustion

. TR W ha s establishe d a targe t fo r sulfu r captur e o f 6 0 t o 9 0 percen t wit h additio n o f lime , bu t ha s decline d t o discus s ho wo r wher e th e lim e i s fe d t o th e system
. Actua l tes t dat a fro m tes t wit hOhio , Pensylvania , an d Wyomin g coal s hav e reportedl yachieve d 5 0 t o 9 0 percen t captur e a t Ca/ S ratio s o f betwee n 3 and 4
. B

ystagin g combustion , reduce d level s o f N O ca n als o b e achieved

. Th e combusto r wa s develope d a t a TR W pilo t plan t i n Californi a and i s bein g teste d i n a n industria l boile r owne d b yTR W i n Cleveland , Ohio

. N o commercia l sale s o f th e combusto r ar e known
. Actua l tes t dat a o n SO

- remova l performanc e hav e no t bee n published

. Compariso n o f SO,
. Captur e Whil e certai n simimlaritie s exis t betwee n th e TA S and TR W systems , the y diffe r i n ho wthe yhandl e as hi n th e coal , whic hi n tur n influence s th e additio n o f lim e fo r SO

- control
. Specifically , th e TA S syste mmaximize s th e numbe r o f as hparticle s i n th e furnac e (b yminimizin g thei r size) ; thi s approac hcreate s as hparticle s tha t ar e smal l enoug ht o follo waerodynami c streamline s aroun d hea t exchange r tube s whil e maximizin g surfac e are a fo r rapi d particl e burnou t and sulfu r capture
. Additiona l sulfu r captur e ca n b e accomplishe d byaddin g lim e o r limeston e t o th e micronizin g mil l alon g wit h th e coa l withou t significantl yaffectin g boile r hea t transfer
. B ycontrast , th e TR W proces s protect s hea t exchang e surface s b yremovin g as ha s a sla g i n th e firs t stag e o f th e combustor
. However , thi s approac hals o reduce s th e coa l alkal i surfac e are a neede d fo r remova l o f sulfur
.P. 5

Actua l tes t dat a measurin g sulfu r captur e wit heithe r system ar e limited . TA S claim s t o hav e achieve d9 0 percen t captur e withou t sorben t additio ndurin g short-term

pilot-scal e test s wit hsevera l coals . However , dat a collecte d durin g thes e test s ar e insufficien t t o evaluat e th e chemistr y o f th e proces s (e.g. , percen t remova l versu s Ca/ S ratio) , it s performanc e o nothe r coals , o r it s scale-u pt o full-siz e industria l boilers . Th e firs t significan t dat a ar e expecte dt o com e from th e boile r recentl y

installe da t St . Loui s Universit y Hospital . Short-ter m pilot-scal e test s a t th e TR W pilo t plan t hav e demonstrate d5 0 t o 9 0 percen t sulfu r capture , bu t a s wit hth e TA S system , full-scal e dat a ar e no t available .
Reference s

1 . TA S System s Description . TAS-COAL , P . 0 . Bo x68 , Magna , Utah . Septembe r 4 , 1986 .

2 . Comment s onEPA' s Propose dSO - Standar dfo r Industria l Boilers . TR W Combustio nBusines s Unit , Redond o Beach , California . Decembe r 1986 .