Flame stability limits and hydrocarbon destruction efficiencies of flares burning waste streams containing hydrogen and inert gases

F L A M E S T A B IL IT Y L IM IT S A N D H Y D R O C A R B O N D E S T R U C T IO N E F F IC IE N C IE S O F F L A R E S B U R N IN G W A S T E S T R E A M S C O N T A IN IN G Peter M. Walsh*, D a v i d K. M o y e d a , G E W. H Y D R O G E N A N D IN E R T G A S E S S t e v e n L a n i e r , C . M i c h a e l B o o t h , E. E. ( G a r y ) F o l k, a n d J o h n - Energy and Maxwell Environmental R e s e a r c h Corporation Morrisville, N C and Irvine, C A W i l f r e d K. W h i t c r a f t E. I. d u Pont de Nemours & C o m p a n y Wilmington, D E R o g e r K. N o b l e t , Jeff M . C l o p t o n J , T r a c y R o g e r s § , a n d C h r i s N i c e l y ^ C a l l i d u s T e c h n o l o g i e s Inc. Tulsa, O K R o b e r t E. R o s e n s t e e l a n d C . A n d r e w Miller U.S. E n v i r o n m e n t a l Protection A g e n c y R e s e a r c h Triangle Park, N C American Combustion Flame Research Committee, 2002 Emission Improvements: Hosted by ChevronTexaco, Technologies, Bellaire, T X , Fall M e e t i n g Requirements, a n d Trends N o v e m b e r 5-6, 2 0 0 2 *Present address: U n i v . of A l a b a m a at B i r m i n g h a m a n d S o u t h e r n R e s e a r c h tPresent address: Continuum ^Present address: J o h n Zink C o m p a n y , §Present address: 2 2 2 S o u t h First, M o r r i s , O K Engineering, L L C , Tulsa, O K L L C , Tulsa, O K 74445. 74136. 74116. Institute, B i r m i n g h a m , A L 35294. Motivation for the Work R e g u la tio n fo r c o m b in a tio n s a n d th e v e lo c ity u p p e r F la r e s fla re s o f in h e a tin g th e ~ 1 5 h y d r o g e n , h a v in g o f o n ly k n o w n e x p e c te d to d e s tr u c tio n v e lo c itie s to a t v o l% 5 0 h e a tin g - 1 0 0 b e h a v e o f ~ 1 0 0 fu e l B tu /s c f, s ta b le a n d h ig h e ffic ie n c ie s S u p p le m e n ta l m e e t r e g io n g a s e s c o n ta in in g w e r e v a lu e le ft. o f w a s te v a lu e s re q u ire d a t ft/s . r e q u ire d to re g u la tio n . V e l o c i t y (ft/s) EER/EPA Flare Test Facility J. H. Pohl, R. "E v a l u a t i o n Industrial U.S. E P A of Payne, the Flares: a n d M a y Lee, Efficiency Test of Results," 600/2-84-095, P B 8 4 - 1 9 9 3 7 1 , J. 1984. N T I S Criterion for High Combustion Efficiency F la re s b u r n in g m ix tu r e s J. H . Pohl, Test R. Payne, a n d Results," U.S. J. L e e , E P A "E v a l u a t i o n 600/2-84-095, p r o p a n e /n itr o g e n w ith of t h e N T I S n o p ilo t f la m e E f f i c i e n c y of Industrial P B 8 4 - 1 9 9 3 7 1 , M a y Flares: 1984. Measurements S t a b ilit y E s ta b lis h v e lo c ity , lim it s : s ta b le th e n r e d u c e H 2- N 2 m ix t u r e b lo w o u t. to W ith D e s t r u c t io n A d d k n o w n h y d r o c a r b o n m e a s u r e its c o m b u s tio n fla m e a n d o f a n d p ilo t. g a s o f a n d c o n c e n tr a tio n in th e p ro d u c ts . c o lo r e le c tr o n ic a lly + lift o f f w ith o u t fla re fr o m O H 2 c o n te n t c o n c e n tr a tio n to g iv e n e ff ic ie n c y : b lu e + a o b s e r v e ( T h e C O a t M is ^ d u e to e m is s io n e x c ite d C O 2* + C O 2: M ) Flare Characteristics T ip i.d . S ta b le 2 .9 fla m e s a n c h o r e d L ift in . o ff: R e = w e r e a t th e p a rt o f th e ( N o s ta b le fr o m tip . s e p a r a tio n fla m e fla m e s s e p a r a te d firm ly p ip e p e r m a n e n t a n y 1 0 5 fr o m th e o f tip . c o m p le te ly th e tip w e r e o b s e rv e d .) B lo w o u t fla m e in o f p ilo t: e x tin g u is h e d . S ta b iliz in g e ffe c t o n a n d a b s e n c e b lo w ta b s th e o u t. h a d n o s ig n ific a n t H 2 c o n te n ts a t lift o f f Stability in the Absence of Pilot E v e n w ith o u t c o m p le te ly d o w n p ilo t, s ta b le fla re s ( n o a re lift o f f ) to : 7 .6 v o l% H 2 a t 2 0 ft/s 1 5 .4 v o l% H 2 a t 1 2 0 ft/s B lo w o u t o c c u r s a p p r o x im a te ly a t 0 .8 H 2 c o n te n ts v o l% lo w e r. Velocity (ft/s) Interaction between Pilot and Flare L ift o ff: ( s a m e p e r m a n e n t o f th e B lo w fla m e fr o m a r o u n d th e b e fo re ) s e p a r a tio n fla m e o u t: a s fr o m n o th e o f a n y tip . p r o p a g a tio n th e p ilo t p a rt in to o f o r je t. * % Lifted t - - Completely stable Effect of Pilot Flame on Stability T h r e e 1 . p ilo t B u r n e r fr o m to rc h . 0 .0 5 2 . - 0 .1 % H e a t 3 . o u tp u t g a s -fire d 1 .0 % In d u s tria l n a tu ra l - h a n d - 2 4 0 h e a t in p u t. v e n tu ri - 2 7 0 0 W ; b u rn e r. W ; o f fla re . p ilo t g a s te s te d : 1 2 0 o f fla re o u tp u t 7 0 0 to 3 0 0 0 w e r e p r o p a n e H e a t N a tu r a l 0 .3 b u r n e r s w ith r e d u c e d o rific e . 1 2 0 0 0 W ; 1 H e a t - o u tp u t 1 0 % o f fla re . H e a t to in p u t to 0 .6 % o f th e D u P o n t fla re p ilo ts h e a t is in p u t. 0 .0 5 Stability in the Presence of Pilot B lo w o u t o c c u r s a p p r o x im a te ly th a n th a t a t In flu e n c e g r e a te s t H 2 c o n te n t 2 H 2 c o n te n t v o l% lo w e r lift o ff. o f a t a t p ilo t h ig h a t h e a t v e lo c ity . b lo w e x tr a p o la te d to (4 .3 v o l% ) g o o d w ith le a n in in p u t o u t z e r o v e lo c ity a g r e e m e n t fla m m a b ility H 2- N 2- O 2 m i x t u r e s (4 .8 lim it fo r v o l% ). No Effect of Pilot on Lift Off C o n d itio n s in th e lift p r e s e n c e a b s e n c e a re a t o f th e o ff a n d p ilo t in d is tin g u is h a b le . Pilot for Destruction Efficiency Tests V e n tu ri b u r n e r p ilo t fo r th e e ffic ie n c y 2 6 8 0 th e te s ts . h e a t D e s tr u c tio n m e a s u r e d a s d e s tr u c tio n B tu /h o u r; o f fla re c h o s e n 0 .2 7 to 0 .4 8 % in p u t. e ffic ie n c y w ith o u t a ls o p ilo t. Difficulty of Destruction U s e e t U n io n a l., C a r b id e 1 9 7 9 ) d e s tr u c tio n b e th e to c o rr e la tio n d e s tr o y e d d iffic u lty o f B e n z e n e 1 3 8 4 oF c o m p o u n d s to A c e to n itrile 1 3 8 3 E th y le n e 1 3 8 3 c o m p a r e o f ty p ic a l a n d ( L e e c a n d id a te s fo r H y d r o g e n m e a s u r e m e n ts . C o r r e la tio n g iv e s re q u ire d a c h ie v e to d e s tr u c tio n in a th e 1 3 5 3 P r o p y le n e 1 3 4 0 P r o p a n e 1 3 1 9 1 ,3 - b u ta d ie n e 1 3 1 4 is o - b u ta n e 1 3 0 2 n - b u ta n e 1 2 4 7 F o r m a ld e h y d e 1 2 4 6 c h lo rid e C a r b o n 1 2 4 4 o r A c e ty le n e 9 9 % r e s id e n c e tim e . P a r a m e te r s : a to m s , g ro u p s , H /C C = C N u m b e r s g ro u p s , w h e th e r ra tio , a n d te m p e r a tu r e . o f C , v in y l a r o m a tic a u to ig n itio n 1 3 6 6 A c ry lo n itrile te m p e r a tu r e s p e c ifie d c y a n id e N , O n o t, m o n o x id e 1 1 1 6 Determination of Destruction Efficiency H o o d u s e d to c o m b u s tio n 0 . 1 9 - p ro d u c ts . 1 . 6 6 e th y le n e c a p tu r e v o l% fo r d e s tr u c tio n m e a s u r e m e n ts . 1 0 v o l% tr a c e r to d ilu tio n P ilo t C O 2 a d d e d a s d e te r m in e b y h e a t e x c e s s in p u t 0 a ir. - 0 .5 % o f fla re . T ip 1 3 v e lo c ity - 1 9 v o l% 9 6 - H 2. 1 2 0 ft/s . M easurem ents A m b i e n t C o n d i t i o n s R e la tiv e h u m id ity T em p eratu re B a ro m etric p r e s s u r e W in d s p e e d C a r b o n d i o x i d e in a ir F la r e a n d P i l o t N itr o g e n flo w H y d r o g e n flo w C a r b o n d i o x i d e in f l a r e g a s E t h y l e n e in f l a r e g a s P ilot f l a m e n a tu r a l g a s flo w F lare g a s te m p e r a tu r e P r o d u c t s C a r b o n d i o x i d e in s t a c k E t h y l e n e in s t a c k S ta c k tem p eratu re S t a c k flo w M easurem ent of Stack Flow Rate T r a v e r se sta c k u sin g P ito t/sta tic p r o b e . V e lo c it y d istr ib u tio n is w e llb eh aved and sy m m etric. In teg ra te p ro files to d e t e r m in e flo w rate. M o n ito r P ito t/sta tic DP on s t a c k c e n t e r l i n e d u r i n g all runs. A ssu m e ratio o f a v e r a g e to c e n t e r lin e v e lo c it y is t h e s a m e for s m a ll d e v ia t io n s fro m th e ca lib ra tio n co n d itio n . Effect of H 2 on Response of Flam e Ionization Detector H ydrocarbon a n a l y z e r w ith fla m e io n iza tio n d e te c to r u sed to m o n ito r e th y le n e c o n t e n t o f fla re g a s . T h e r e is a w e ll k n o w n of hydrogen effect on th e resp o n se o f FID . E f f e c t is s m a l l o v e r t h e r a n g e of co n d itio n s in v estig a ted . N e g l e c t o f lo w e r r e s p o n s e is c o n se r v a tiv e (eth y len e fe e d i s in t h e d e n o m i n a t o r o f t h e d e str u c tio n efficien cy ). Destruction Efficiencies M e a u r e m e n ts r e p e a te d 4 to 7 D e stro y e d tim es. Error b a rs in d ica te m in im u m N ot d estru ctio n effic ien cy at 9 5 % E th y le n e c o n f id e n c e lev el. D estru ctio n e ffic ie n c ie s a re a b o v e 98% at a lev el o f 9 5 % F ra c tio n of c o n f i d e n c e in a ll c a s e s . D estru ctio n effic ien cy i n c r e a s e s w ith h y d r o g e n a n d eth y le n e con ten t. 12 14 16 V o lu m e F ra c tio n 18 H 2 (% ) 20 Correlation of Destruction Efficiencies B e h a v io r of h y d r o g e n fla res d o m in a ted by h yd rogen con ten t rather th a n h ea tin g v a lu e. A d a p t sta b ility ratio o f P o h l a n d c o w o r k e r s to h y d r o g e n fla res u sin g H 2 con ten t. C h o o se r e fe r e n c e co n d itio n a s H 2 c o n t e n t a t lift o f f , b e c a u s e is w e ll - d e f i n e d and it in d ep en d en t o f p ilot. D estru ctio n e ffic ie n c ie s a r e w ell a b o v e 98% a t sta b ility r a tio s o f 1 and h ig h er. R a t i o o f A c t u a l H 2 t o H 2 a t L if t O f f Conclusion H ydrogen flare con ten ts w ere and v elo cities reco m m en d ed a s a t li ft o f f o f t h e criteria fla m e g u a ra n teein g from greater th e 2 .9 -in ch than 98% d ia m eter d estru ctio n e f f i c i e n c y in h y d r o g e n f l a r e s . R eco m m en d ed v elo city m a k in g th at it an y m ore fla re h a v in g sta b le than a at co m b in a tio n lift off b e of hydrogen co n sid ered a con ten t and hydrogen tip fla re, ir r e sp e c tiv e of th e c o n c e n tr a tio n s of o th e r fu el g a s e s . G eneral P ro v isio n s for N ew S ou rce P erform an ce G e n e r a l P r o v is io n s for N a tio n a l E m is s io n S ou rce C a teg o rie s (40 C F R 6 3 .1 1 ) (40 C F R 6 0 .1 8 ) and S t a n d a r d s fo r H a z a r d o u s A ir P o l l u t a n t s fo r a m en d ed h y d r o g e n -fu e le d fla res, e ffe c tiv e J u n e 2 3 , S tan d ard s 19 9 8 to in clu d e sep arate sp ecifica tio n (F e d e r a l R e g iste r , M a y 4, 1 9 9 8 ). for Acknowledgments T h is w ork w a s su p p o r te d b y E . I. D u Pont d e N em ou rs & C om pany. T h a n k s a ls o to: V an B r a w le y , E llen L a n e , M a ry N u x o ll, R o b e r t P erry, a n d W a lte r S c h r im p e r o f D uP ont T erry H a rriso n a n d B ria n D u c k , M ik e K eller, R o g e r P o e , G e n e R iley o f U .S . R ick J a m e s , C h a d E PA O g d e n , J im S tock ton, an d S c o tt G u th rie of C a llid u s T e c h n o lo g ie s Frank S tev en s, John B ob Pohl (n ow Jerald C o le (n o w an E lliott, P e t e r M a l y , R o y P a y n e , J e r r y J o h n s o n , at th e U n iv e r sity o f Q u e e n s la n d , A u stra lia ), a n d in d e p e n d e n t co n su lta n t o n hydrogen pow er) of G E - E E R