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# 1870 Prepped byOllie Stewart



## Document

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# V>_:P A Unite d State s Environmenta l Protectio n Agenc y Ai ran d EnergyEngineerin g Researc h Laborator

y Researc h Triangl e Park , N C 2771 1 Technolog yTransfe r 

# A-90-1 9 ll-A-2 7 

# Handboo k Contro l Technologie s fo r Hazardou s Ai rPollutant sP. 3

I 

### EPA/625/6-86/01 4 September1986



# Handboo k Contro l Technologie s fo r Hazardou s Ai rPollutant s

Ai ran d Energ

yEngineerin g Research Laborator y Office o fResearch an d Development U.S . Environmenta l Protectio n Agenc y Research Triangl e Park, N C 2771 1 Cente rfo rEnvironmenta l Researc h Informatio n Offic e ofResearc h an d Developmen t U.S . Environmenta l Protectio n Agency

Cincinnati , O H 4526 8

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### Notice Thi s documen t ha s bee n reviewe d i n accordanc e wit h th e U. S Environmen ta l Protectio n Aqency' s pee ran d administrativ e revie wpolicie s an d ap prove d fo rpublication . Mentio n o ftrad e name s o rcommercia l product s doe s no t constitut e endorsemen to rrecommendatio n fo ruse .

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## Foreword Today' s rapidl ychangin g industria l technologies , products , an d practice s frequentl ycarr ywit h the m a n increasin g generatio n o fhazardou s ai rpollu tant s (HAPs) . Whe n energ yan d materia l resource s ar e extracted , processed , converted , an d used , th e consequen timpact s o n healt h an d th e environmen t requir e tha t efficien t pollutio n contro l method s b e used . Th e 197 0 amendment s t o th e Clea n Ai rAc trequir e th e U.S . Environmenta l Protectio n Agenc y(EPA) t o se tNationa l Ambien tAi rQualit yStandard s fo r criteri a ai rpollutant s foun d throughou tth e country . Th e Clea n Ai rAc t Amendment s als o requir e EP At o revie wan d regulat e hazardou s ai rpollu tants , define d as thos e ai rpollutant s tha tca n contribut e t o increase d mortal it yo rseriou s illnes s bu twhic h ar e no talread yregulate d as criteri a pollutants . Sinc e th e definitio n o fa HA P i s ver ybroa d an d encompasse s thousand s o f specifi ccompounds , i ti s no tpractica l t o develo p a n all-inclusiv e lis to fHA P compound s an d compound-specifi ccontro l techniques . However , th e num be ro fgeneri cai rpollutio n contro l technique s availabl e i s small , an d th e factor s affectin g th e cos tan d performanc e o fthes e control s a s applie d t o man ynoncriteri a pollutant s hav e bee n identifie d an d discusse d i n th e literature . Th e purpos e o fthi s handboo k i s t o hel p EP

Aregional , State , an d loca l ai r pollutio n contro l agenc ytechnica l personne l select , evaluate , an d cos tai r pollutio n contro l technique s fo rreducin g o reliminatin g th e emissio n o f potentiall yhazardou s ai rpollutant s fro m industrial/commercia l sources . Th e informatio n provide d b ythi s documen twil l b e usefu l fo rreviewin g permi t application s o rfo rinformin g intereste d partie s o fth e type , basi cdesign , an d cos t o favailabl e HA P contro l systems .P. 6



### Acknowledgments Thi s handboo k

ha s bee n adapte d fro m a two-volum e EP Arepor ttitle d Evaluation of Control Technologies

for Hazardous

Air Pollutants. Th e repor twa s writte n b yRobert Y . Purcell , Pacifi cEnvironmenta l Service s Inc. , Durham , Nort h Carolina , an d Gunsel i Sagu n Shareef , Radia n Corporation , Researc h Triangl e Park , Nort h Carolina . The ywer e assiste d by : Vishn u S . Katari , Kari n C . C . Gschwandtner , Michae l K. Sink , an d Charlott e R . Clar k o fPacifi cEnvi ronmenta l Service s Inc. ; an d Andre wJ . Miles , D . Blak e Bath , an d Glynd a E . Wilkin s o fth e Radia n Corporation . Dr . Bruc e A . Ticheno ro fEPA' s Ai ran d Energ yEngineerin g Researc h Laboratory , Researc h Triangl e Park , Nort h Carolina , wa s th e EPAprojec toffice rfo rth e report . Thi s handboo k

wa s adapte d an d produce d b yJAC ACorporation , FortWash - [ ington , Pennsylvania . Norma n Kulujia n o fEPA' s Cente rfo rEnvironmenta l '. Researc h Information , Cincinnati , Ohio , wa s th e EPAprojec toffice rfo rthi s publication . i I fyo u wis h t o obtai n th e mor e detaile d tw o volum e report , i s i s availabl e fro m | th e Nationa l Technica l Informatio n Servic e (NTIS) , 528 5 Por t Roya l Road , j Springfield , Virgini a 22161 ; (703 ) 487-4650 . Th e orde rnumber s are : j Volum e I . Technica l Report ; P B 86-16 7 020 ; EPA/600/7-86/009 a Volum e II . Appendices ; P B 86-1670038 ; EPA/600/7-86/009 b



# k_ _P. 7

fo rspecifi cHAP' s ar e available . Therefore , withou t actua l sourc e tes t dat a fo ra specifi cemissio n strea m an d contro l system , HA P remova l efficienc y i s assume d t o equa l tota l volatil e organi ccom poun d (VOC ) remova l efficiency . 3.2.1. 1 Therma l Incinerator s Therma l incinerator s ar e use d t o contro l a wid e variet yo fcontinuou s emissio n stream s containin g VOC's . Compare d t o th e othe rtechniques , therma l incineratio n i s broadl yapplicable ; tha tis , i ti s muc h les s dependen t o n HA P characteristic s an d emis sio n strea m characteristics . Destructio n efficiencie s u p t o 99 + percen t ar e achievabl e wit h therma l in cineration . Althoug h the yaccommodat e mino r fluctuation s i n flow , therma l incinerator s ar e no t wel l suite d t o stream s wit h highl yvariabl e flo w becaus e th e reduce d residenc e tim e an d poo rmix in g durin g increase d flo wcondition s decreas e th e completenes s o fcombustion . Thi s cause s th e com bustio n chambe rtemperatur e t o fall , thu s decreas in g th e destructio n efficiency . Therma l incineratio n i s typicall yapplie d t o emis sio n stream s tha t ar e dilut e mixture s o fVO C an d air . I n suc h cases , du e t o safet yconsiderations , concentratio n o fth e VOC' s i s generall ylimite d b y insuranc e companie s t o 2 5 percen t o fth e LE L(low e rexplosiv e limit ) fo rth e VO C i n questio n (se e Sectio n 4.2. 2 fo rmor e details) . Thus , i fth e VO C concentratio n i s high , dilutio n ma yb e required . Whe n emissio n stream s treate d b ytherma l inciner atio n ar e dilut e (i.e. , lo whea t content) , supplemen tar yfue l i s require d t o maintai n th e desire d com bustio n temperatures . Supplementar yfue l requirement s ma yb e reduce d b yrecoverin g th e energ ycontaine d i n th e ho t flu e gase s fro m th e incinerator . Fo remissio n stream s wit h hig h hea t content s (e.g. , > 15 0 Btu/scf) , th e possibilit yo fus in g th e emissio n strea m a s fue l ga s shoul d b e con sidered . Package d singl e uni t therma l incinerator s ar e avail abl e i n man ysize s t o contro l emissio n stream s wit h flo wrate s fro m a fe whundre d u p t o abou t100,00 0 scfm . 3.2.1. 2 Catalyti c Incinerator s Catalyti cincinerator s ar e simila rt o therma l inciner ator s i n desig n an d operatio n excep ttha tth e for me remplo ya catalys t t o enhanc e th e reactio n rate . Sinc e th e catalys t allow s th e reactio n t o tak e plac e a t lowe rtemperatures , significan t fue l saving s ar e possibl e wit h catalyti cincineration . Catalyti cincineratio n i s no t a s broadl yapplie d a s therma l incineratio n sinc e performanc e o fcatalyti c incinerator s i s mor e sensitiv e t o pollutan tcharac teristic s an d proces s condition s tha n i s therma l in cinerato rperformance . Material s suc h a s phospho rus , bismuth , lead , arsenic , antimony , mercury , iro n oxide , tin , zinc , sulfur , an d halogen s i n th e emissio n strea m ca n poiso n th e catalys tan d se verel yaffec tit s performance . (Note : Som e cata lyst s ca n handl e emissio n stream s containin g halo genate d compounds. ) Liqui d o rsoli d particle s tha t deposi to n th e catalys tan d for m a coatin g als o reduc e th e catalyst' s activit yb ypreventin g contac t betwee n th e VOC' s an d th e catalys tsurface . Cata lys tlif e i s limite d b ytherma l agin g an d b ylos s o f activ e site s b yerosion , attrition , an d vaporization . Wit h prope roperatin g temperature s an d adequat e temperatur e control , thes e processe s ar e normall y slow , an d satisfactor yperformanc e ca n b e main taine d fo r3 t o 5 year s befor e replacemen to fth e catalys t i s necessary . Catalyti cincineratio n i s generall yles s expensiv e tha n therma l incineratio n i n treatin g emissio n stream s wit h lo wVO C concentrations . Emissio n stream s wit h hig h VO C concentration s shoul d no t b e treate d b ycatalyti cincineratio n withou tdilutio n sinc e suc h stream s ma ycaus e th e catalys tbe d t o overhea tan d los e it s activity . Also , fluctuation s i n th e VO C conten to fth e emissio n strea m shoul d b e kep tt o a minimu m t o preven tdamag e t o th e cata lyst . Destructio n efficiencie s o fu p t o 9 5 percen to f HAP' s ar e generall yachieve d wit h catalyti cinciner ation . Highe rdestructio n efficiencie s (9 9 percent ) ar e als o achievable , bu trequir e large rcatalys tvol ume s and/o rhighe rtemperatures . Catalyti cincinerator s hav e bee n applie d t o continu ou s emissio n stream s wit h flo wrate s u p t o abou t 100,00 0 scfm . 3.2.1. 3 Flare s Flare s ar e commonl yuse d fo rdisposa l o fwast e gase s durin g proces s upset s (e.g. , start-up , shut down ) an d emergencies . The yar e basicall ysafet y device s tha tar e als o use d t o destro ywast e emis sio n streams . Flare s ca n b e use d fo rcontrollin g almos tan yVO C emissio n stream . The yca n b e designe d an d oper ate d t o handl e fluctuation s i n emissio n VO C con tent , inert s content , an d flo wrate . Ther e ar e severa l differen ttype s o fflare s includin g steam-assisted , air-assisted , an d pressur e hea d flares . Steam-as siste d flare s ar e ver ycommo n an d typicall yem ploye d i n case s wher e larg e volume s o fwast e gas e s ar e released . Air-assiste d flare s ar e generall y use d fo rmoderat e relie fga s flows . Pressur e hea d flare s ar e small ; the yar e use d i n array s o fu p t o 10 0 individua l flares . Normally , onl ya fe wo fth e flare s operate . Th e numbe ro fflare s operatin g i s in crease d a s th e ga s flo wincreases . Flarin g i s generall yconsidere d a contro l optio n whe n th e heatin g valu e o fth e emissio n strea m 25P. 8

' canno t b e recovere d becaus e o funcertai n o rinter mitten t flo wa s i n proces s upset s o remergencies . I f th e wast e ga s t o b e flare d doe s no t hav e sufficien t heatin g valu e t o sustai n combustion , auxiliar yfue l ma yb e required . Base d o n studie s conducte d b yEPA , 9 8 percen t destructio n efficienc yca n b e achieve d b ysteam assiste d flare s whe n controllin g emissio n stream s wit h hea t content s greate rtha n 30 0 Btu/scf . De pendin g o n th e typ e o fflar e configuratio n (e.g. , elevate d o rgroun d flares) , th e capacit yo fflare s t o trea t wast e gase s ca n vary—u p t o abou t 100,00 0 lb/h rfo rgroun d flare s an d 2 millio n lb/h ro rmor e fo relevate d flares . Th e capacit yo fa n arra yo fpres sur e hea d flare s depend s o n th e numbe ro fflare s i n th e array . 3.2.1 . < Existin g boiler s o rproces s heater s ca n b e use d t o contro l emissio n stream s containin g organi ccom pounds . Thes e ar e currentl yuse d a s contro l de vice s fo remissio n stream s fro m severa l industrie s (e.g. , refiner yoperations , SOCM I reacto rprocesse s an d distillatio n operations , etc. ) Typically , emissio n stream s ar e controlle d i n boil er s o rproces s heater s an d use d a s supplementa l fue l onl yi fthe yhav e sufficien t heatin g valu e (greate rtha n abou t 15 0 Btu/scf) . I n som e instances , emissio n stream s wit h hig h hea t conten t ma yb e th e mai n fue l t o th e proces s heate ro rboile r(e.g. , proces s off-ga s fro m ethylbenzene/styren e manu facturing) . Not e tha t emissio n stream s wit h lo w hea t conten t ca n als o b e burne d i n boiler s o rpro ces s heater s whe n th e flo wrat e o fth e emissio n strea m i s smal l compare d t o th e flo wrat e o fth e fuel/ai rmixture . Whe n use d a s emissio n contro l devices , boiler s o r proces s heater s ca n provid e destructio n efficien cie s o fgreate rtha n 9 8 percen t a t smal l capita l cos t an d littl e o rn o fue l cost . I n addition , nea rcomplet e recover yo fth e emissio n strea m hea t conten ti s possible . Ther e ar e som e limitation s i n th e applicatio n o f boiler s o rproces s heater s a s emissio n contro l de vices . Sinc e thes e combustio n device s ar e essentia l t o th e operatio n o fa plant , onl ythos e emissio n stream s tha t wil l no t reduc e thei rperformanc e o r reliabilit yca n b e controlle d usin g thes e devices . Variation s i n emissio n strea m flo wrat e and/o r heatin g valu e coul d adversel yaffec t th e perfor manc e o fa boile ro rproces s heater . Bylowerin g furnac e temperatures , emissio n stream s wit h larg e flo wrate s an d lo wheatin g value s ca n caus e incom plet e combustio n an d reduc e hea t output . Th e per formanc e an d reliabilit yo fth e proces s heate ro r boile rma yals o b e affecte d b yth e presenc e o fcor rosiv e compound s i n th e emissio n stream ; suc h stream s ar e usuall yno t destroye d i n thes e devices . 26 3.2.U JCsirbotn_k9_ortb>®. s Carbo n adsorptio n i s commonl yemploye d a s a pollutio n contro l and/o ra solven trecover ytech nique . I ti s applie d t o dilut e mixture s o fVO C an d air . Remova l efficiencie s o f9 5 t o 9 9 percen tca n b e achieve d usin g carbo n adsorption . Th e maximu m practica l inle t concentratio n i s usuall yabou t10,00 0 ppmv . Th e inle tconcentration s ar e typicall ylimite d b yth e adsorptio n capacit yo fth e carbo n be d o r safet yproblem s pose d b yhig h be d temperature s produce d b yhea to fadsorptio n an d presenc e o f flammabl e vapors . Outle tconcentration s o f5 0 t o 10 0 ppm vca n b e routinel yachieve d wit h state-of the-ar tsystems ; concentration s a s lo wa s 1 0 t o 2 0 ppm vca n b e achieve d wit h som e compounds . I n contras tt o incineratio n method s whereb yth e VOC' s ar e destroyed , carbo n adsorptio n provide s a favorabl e contro l alternativ e whe n th e VOC' s i n th e emissio n strea m ar e valuable . Hig h molecular-weigh tcompound s tha tar e charac terize d b ylo wvolatilit yar e strongl yadsorbe d o n carbon . Th e affinit yo fcarbo n fo rthes e compound s make s i tdifficul tt o remov e the m durin g regenera tio n o fth e carbo n bed . Hence , carbo n adsorptio n i s no tapplie d t o suc h compound s (i.e. , boilin g poin t abov e 400°F ; molecula rweigh tgreate rtha n abou t 130) . Highl yvolatil e material s (i.e. , molecula r weigh t les s tha n abou t45 ) d o no tadsor b readil yo n carbon ; therefore , adsorptio n i s no ttypicall yuse d fo rcontrollin g emissio n stream s containin g suc h compounds . Carbo n adsorptio n i s relativel ysensitiv e t o emis sio n strea m conditions . Th e presenc e o fliqui d o r soli d particles , hig h boilin g organics , o rpolymeri zabl e substance s ma yrequir e pretreatmen tproce dure s suc h a s filtration . Dehumidificatio n i s neces sar yi fth e emissio n strea m ha s a hig h humidit y (relativ e humidit y> 5 0 percent ) an d coolin g ma y b e require d i fth e emissio n strea m temperatur e ex ceed s 120°-130°F . T o preven texcessiv e be d temperature s resultin g fro m th e exothermi cadsorptio n proces s an d oxida tio n reaction s i n th e bed , concentration s highe r tha n 10,00 0 ppm vmus tfrequentl yb e reduced . Thi s i s usuall ydon e b ycondensatio n o rdilutio n o fth e emissio n strea m ahea d o fth e adsorptio n step . Ex othermi creaction s ma yals o occu ri fincompatibl e solvent s ar e mixe d i n th e bed , leadin g t o polymer ization . I fflammabl e vapor s ar e present , th e VO C concentration s ma yb e limite d b yinsuranc e com panie s t o les s tha n 2 5 percen to fth e LEL . I fprope r control s an d monitor s ar e used , LE Llevel s u p t o 4 0 t o 5 0 percen tma yb e allowed . Package d carbo n adsorptio n system s ar e availabl e tha tca n handl e emissio n stream s wit h flo wrate s fro m a fe whundre d t o abov e 100,00 0 scfm .

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i _r_______r_si_n_____iP. 9

3.2.1. 6 Absorber s (Scrubbers ) Absorptio n i s widel yuse d a s a ra wmateria l and/o r a produc t recover ytechniqu e i n separatio n an d pu rificatio n o fgaseou s stream s containin g hig h con centration s o fVOC's . A s a n emissio n contro l tech nique , i t i s muc h mor e commonl yemploye d fo r inorgani cvapor s (e.g. , hydroge n sulfide , chlorides , etc. ) tha n fo rorgani cvapors . Usin g absorptio n a s th e primar ycontro l techniqu e fo rorgani cvapo r HAP' s i s subjec t t o severa l limitation s an d prob lem s as discusse d below . Th e suitabilit yo fabsorptio n fo rcontrollin g organi c vapo remission s i s determine d b ysevera l factors ; mos t o fthes e factor s wil l depen d o n th e specifi c\ HA P i n question . Fo rexample , th e mos timportan t facto ri s th e availabilit yo fa suitabl e solvent . Th e pollutan t i n questio n shoul d b e readil ysolubl e i n ' th e solven t fo reffectiv e absorptio n rate s an d th e \ spen t solven t shoul d b e easil yregenerate d o rdis - < pose d o fi n a n environmentall yacceptabl e manner . J Anothe rfacto rtha t affect s th e suitabilit yo fabsorp tio n fo rorgani cvapo remission s contro l i s th e availabilit yo fvapor/liqui d equilibriu m dat a fo rth e specifi cHAP/solven t syste m i n question . Suc h dat a ar e necessaryfo rdesig n o fabsorbe rsystems . Fo r uncommo n HAP's , thes e dat a ar e no t readil yavail able . Anothe rconsideratio n involve d i n th e applicatio n o fabsorptio n a s a contro l techniqu e i s disposa l o f th e absorbe reffluen t (i.e. , use d solvent) . I fth e ab sorbe reffluen t containin g th e organi ccompound s i s discharge d t o th e sewer , pond , etc. , th e ai rpollu tio n proble m i s merel ybein g transforme d int o a wate rpollutio n problem . Hence , thi s questio n shoul d b e addresse d (e.g. , ar e ther e chemical/phy sical/biologica l mean s fo rtreatin g th e specifi cefflu en t unde rconsideration?) . I n solven trecovery , use d organi csolvent s ar e typicall ystrippe d (re vers e o fabsorption ) an d recycle d t o th e absorbe r fo reconomi creasons . However , i n HA P contro l applications , strippin g requirement s wil l ofte n b e ver yexpensiv e becaus e th e residua l organi ccon centration s i n th e solven t mus t b e extremel ylo w fo ri t t o b e suitabl e fo rreuse . Also , i fth e VOC' s i n th e effluen t fro m th e absorbe rhav e appreciabl e vapo rpressur e (e.g. , > 0. 1 m m Hg) , th e possibilit y o fVO C emission s t o th e atmospher e shoul d b e considered . I n organi cvapo rHA P contro l applications , lo wout le t concentration s wil l typicall yb e required . Tryin g t o mee t suc h requirement s wit h absorptio n alon e wil l lea d t o impracticall ytal l absorptio n towers , lon g contac t times , an d hig h liquid-ga s ratio s tha t ma yno t b e cos t effective . Therefore , absorber s wil l generall yb e effectiv e whe n the yar e use d i n combi natio n wit h othe rcontro l device s suc h a s inciner ators . Remova l efficiencie s i n exces s o f9 9 percen tca n b e achieve d wit h absorption . 3.2.1. 7 Condenser s Condenser s ar e widel yuse d a s ra wmateria l and/o r produc trecover ydevices . The yar e frequentl yap plie d a s preliminar yai rpollutio n contro l device s fo rremovin g VO C contaminant s fro m emissio n stream s prio rt o othe rcontro l device s suc h as in cinerators , adsorbers , o rabsorbers . Condenser s ar e als o use d b ythemselve s fo rcon trollin g emissio n stream s containin g hig h VO C concentration s (usuall y> 5,00 0 ppmv) . I n thes e cases , remova l efficiencie s obtaine d b ycondenser s rang e fro m 5 0 t o 9 0 percent . Th e remova l efficienc y o fa condense ri s dependen to n th e emissio n strea m characteristic s includin g th e natur e o fth e HA P i n questio n (vapo rpressure-temperatur e rela tionship ) an d HA P concentration , an d th e typ e o f coolan tused . Not e tha ta condense rcanno tlowe r th e inle tVO C concentratio n t o level s belo wth e saturatio n concentratio n (o rvapo rpressure ) atth e coolan ttemperature . Whe n water , th e mos tcom monl yuse d coolant , i s employed , th e saturatio n condition s represen thig h outle tconcentrations . Fo rexample , condense routle tVO C concentration s ar e ofte n limite d t o abov e 10,00 0 t o 20,00 0 ppm v du e t o th e saturatio n condition s o fmos to fth e organi ccompound s a tth e temperatur e o fth e cool in g water . Therefore , i ti s no tpossibl e fo rconden satio n wit h wate ra s th e coolan tt o achiev e th e lo w outle tconcentration s tha twoul d b e require d i n HA P contro l applications . Remova l efficiencie s abov e 9 0 percen tca n b e achieve d i flowe rtemperature s tha n thos e possibl e wit h coolin g wate rar e employed . Thes e lo wtem perature s ca n b e obtaine d wit h coolant s suc h a s chille d water , brin e solutions , o rchlorofluorocar bons . However , fo rextremel ylo woutle tHA P con centrations , condensatio n wil l usuall yb e economi call yinfeasible . Dependin g o n th e typ e o fcondense rused , ther e ma yb e potentia l problem s associate d wit h th e dis posa l o fth e spen tcoolant . Therefore , usin g contac t condenser s tha tgenerat e suc h effluent s fo rcon trollin g HA P emission s i s no trecommended . Flo wrate s u p t o abou t2,00 0 scf m ca n b e consid ere d a s representativ e o fth e typica l rang e fo rcon denser s use d a s emissio n contro l devices . Con denser s fo remissio n stream s wit h flo wrate s abov e 2,00 0 scf m an d containin g hig h concentration s o f noncondensible s wil l requir e prohibitivel ylarg e hea ttransfe rareas . 27