Anto nio C. Caputo and Pac ific o M. Pe lagagge Ec o no mic c o mpariso n o f pulse d e le c tro static pre c ipitato rs and fabric filte rs in c o al-fire d utility plants Enviro nme ntal Manage me nt and He alth
1 0 / 2 [1 9 9 9 ] 9 6 –1 0 4
cor r es p on d in g t ot a l ca p it a l in ves t m en t (TCI), a n n u a l op er a t in g cos t s (AC), a n d t ot a l a n n u a l cos t s (TAC) for t h e fi ve a ir p ollu t ion con t r ol d ev ices con sid er ed . In ca se of F F, n o a t t em p t t o eva lu a t e cos t s ou t s id e t h e d ecla r ed va lid it y r a n ge of ava ila ble cor r ela t ion s h a s b een m a d e. T h er efor e, n ot a ll k in d s of F F h ave b een s ized a n d cos t ed over t h e en t ir e fl ow r a t e r a n ge. H ow ever, for la r ge fl ow r a t es, i.e. la r ge b a gh ou s es, t h e fl ow r a t e h a s b een sp lit b et w een t wo p a r a llel u n it s t h a t h ave b een sin gu la r ly cos t ed , giv in g r ise t o t h e d iscon t i-n u it ies a p p ea r ii-n g ii-n t h e fi gu r es.
F igu r e 1 d e p ict s t h e TCI a ccor d in g t o t h e t wo con s id er ed efficien cy va lu es. In t h e ca s e of low r es is t iv it y coa l (F igu r e 1a ), w h er e n o b en efi t in effect ive m igr a t ion velocit y ca n b e exp ect ed fr om p u ls ed en er giza t ion , t h e col-lect in g p la t e a r ea is t h e s a m e (SCA = 45.2 a n d 56.2s / m d e p en d in g on efficien cy ) a n d p u ls ed E SP r esu lt s m or e exp en s ive d u e t o t h e h igh er cos t of t h e p ow er s u p p ly u n it s. P J F F a n d SF F
sh ow r ou gh ly t h e sa m e cost , w h ich is less t h a n RGF F ca p it a l in vest m en t d u e t o t h e low er r eq u ir ed b a g a r ea t h a n k s t o t h e h igh er a llow a ble ACR. In p a r t icu la r, t h e effect s of size r ed u ct ion is ev id en t for P J F F w h ich a r e ch a r a ct er ized by t h e low est ca p it a l cost even if t h e sp ecifi c b a g cost is h igh er, w h ile RGF F sh ow t h e h igh est ca p it a l cos t . In t h e ca se of m ed iu m r esist iv it y d u s t t h e low er SCA of p u lsed E SP (SCAc= 50.4s/ m , SCAp= 43s/ m a t
low efficien cy, w h ile SCAc= 62.6s/ m , SCAp= 53.4s/ m a t h igh efficien cy ) is offset by t h e cost of t h e en er giza t ion eq u ip m en t r esu lt in g in n ea r ly eq u iva len t TCI of b ot h p r ecip it a t or t y p es. Ben efi t s a r isin g fr om p u lsed en er giza -t ion fu lly sh ow in s-t ea d in ca s e of h igh r esis-t iv iesis-t y d u sesis-t w h er e esis-t h e r ed u ced p la esis-t e a r ea (F ig-u r e 1b : SCAc= 75.6 s / m , SCAp= 50.7 s/ m
w h en efficien cy is 0.99 or SCAc= 93.9 s/ m ,
SCAp= 63 s/ m w h en efficien cy is 0.995) fu lly
offset s t h e in cr ea sed cost of p ow er su p p ly a n d t h e op p osit e sit u a t ion w it h r esp ect t o F igu r e 1a is ob s er ved w h en com p a r in g E SP cost s, r esu lt in g in t h e con ven t ion a l E SP b ecom in g t h e h igh est in vest m en t op t ion , w h ile t h e p u lsed E SP r em a in s com p et it ive w it h t h e RGF F. H ow ever, a s fa r a s ca p it a l cost s a r e con cer n ed , P J F F a n d SF F r es u lt a lw ay s t h e low es t cos t op t ion u n les s a low er E SP effi-cien cy is sp ecifi ed .
Wh en op er a t in g cost s a r e con sid er ed (F ig-u r es 2a a n d b, r efer r in g r esp ect ively t o low a n d h igh d u st r esist iv it y ) p u lsed E SP cost s a r e a lw ay s low er t h a n con ven t ion a l E SP d u e t o t h e low er sp ecifi c cor on a p ow er, even in ca se of low r esist iv it y coa l. T h e cost sav in g in cr ea ses a s d u st r esist iv it y r is es d u e t o t h e a d d ed b en efi t of a r ed u ced p la t e a r ea (F igu r e 2b ). Mor eover, E SP a n n u a l cost s a r e low er t h a n cor r esp on d in g cost s of F F w h ich a r e p en a lized by t h e p er iod ica l b a g r e p la cem en t . On ly in ca se of ver y h igh r esist iv it y coa l (F igu r e 2b ) a n d h igh efficien cy t h e r esu lt in g collect in g a r ea of con ven t ion a l E SP m ay lea d t o cos t s gr ea t er t h a n t h a t sh ow n by fa b r ic fi lt er s (SF F ). P J F F a n d RGF F exp er ien ce t h e h igh es t op er a t in g cost s a m on g F F, in t h e fi r st ca se d u e t o t h e sh or t er b a g life a n d t h e m u ch h igh er sp ecifi c b a g cos t , a n d in t h e la t t er ca se ow in g t o t h e m u ch h igh er fi lt er in g su r fa ce, w h ile SF F sh ow low er cost in r esp ect t o RGF F d u e t o t h e low er r eq u ir ed a r ea (h igh er a llow -a ble ACR) even if b -a g life is sh or t er.
F in a lly, t h e t ot a l a n n u a l cost , in clu d in g ca p it a l r ecover y, is a n a ly zed in F igu r es 3 a n d 4. T h is is t h e m a in econ om ic p a r a m et er t h a t m ay h elp in t h e ch oice of t h e low es t cost p ol-lu t ion con t r ol op t ion . F igu r e 3 d e p ict s TAC in t h e ca se of low E SP efficien cy (99 p er cen t ) w h ile F igu r e 4 r efer s t o h igh collect ion efficien cy (99.5 p er cen t ). In t h is ca se t h e cou n t er -a ct in g effect s of low er c-a p it -a l cost s -a n d Figure 1
Anto nio C. Caputo and Pac ific o M. Pe lagagge Ec o no mic c o mpariso n o f pulse d e le c tro static pre c ipitato rs and fabric filte rs in c o al-fire d utility plants Enviro nme ntal Manage me nt and He alth
1 0 / 2 [1 9 9 9 ] 9 6 –1 0 4
h igh er op er a t in g ch a r ges for F F a r e
ev id en ced , w h ile t h e op p os it e ca n b e s a id for E SP. P J F F a n d SF F sh ow s im ila r cos t s, m a r k ed ly les s t h a n RGF F d u e t o t h e low er r eq u ir ed b a g a r ea t h a n k s t o t h e h igh er a llow -a ble ACR. T h is exp l-a in s t h e su cces s r ecen t ly en cou n t er ed by P J F F in u t ilit y a p p lica t ion s n ow t h a t t h is t ech n ology is fu lly m a t u r e. In p a r t icu la r P J F F TAC is sligh t ly la r ger t h a n SF F, in s p it e of t h e s u p er ior s ize r ed u ct ion effect , d u e t o a h igh er op er a t in g cos t ca u s ed by t h e s h or t er b a g life a n d t h e m u ch h igh er sp ecifi c b a g cost .
As fa r a s E SP a r e con cer n ed a d ist in ct ion h a s t o b e m a d e b et w een low a n d m ed iu m t o h igh d u s t r es is t iv it y. In fa ct , a s a con seq u en ce of t h e ob s er ved t r en d s in E SP ca p it a l a n d op er a t in g cos t s, t h e p u ls ed t y p e is a lw ay s con ven ien t in r esp ect of con ven t ion a l E SP in ca s e of m ed iu m t o h igh r es is t iv it y, bu t n ot in ca s e of low r es is t iv it y (F igu r es 3a , 4a ). Wit h low r es is t iv it y coa l p u lsed or con ven t ion a l E SP a r e a low er cost op t ion com p a r ed t o F F (F igu r es 3a , 4a ) bu t t h is com p et it ive m a r gin
r ed u ces a s t h e r eq u ir ed efficien cy in cr ea ses. In m ed iu m r esis t iv it y coa l a p p lica t ion s con -ven t ion a l E SP a r e st ill a com p et it ive op t ion , w it h p u lsed E SP b ein g in s t ea d a low er cost op t ion in com p a r is on w it h F F. In t h e ca se of h igh r es ist iv it y in s t ea d (F igu r es 3c, 4c) con ven t ion a l E SP a r e a lw ay s m or e cost ly Figure 2
Annual o pe rating c o sts: (a) lo w, (b) high re sistivity c o al
Figure 3
Anto nio C. Caputo and Pac ific o M. Pe lagagge Ec o no mic c o mpariso n o f pulse d e le c tro static pre c ipitato rs and fabric filte rs in c o al-fire d utility plants Enviro nme ntal Manage me nt and He alth
1 0 / 2 [1 9 9 9 ] 9 6 –1 0 4
t h a n fa b r ic fi lt er s (esp ecia lly P J F F a n d SF F ), w it h p u ls ed E SP b ein g less cos t ly a t low effi-cien cy a n d com p et it ive a t h igh effieffi-cien cy. In con clu s ion , a t low t o m ed iu m r es is t iv it y b ot h k in d s of E SP a r e com p et it ive or con ven ien t in r esp ect t o F F, w h ile a t h igh r es is t iv it y on ly p u ls ed E SP is eit h er com p et it ive or
con ven ien t a ccor d in g t o t h e fl ow r a t e t o b e t r ea t ed a n d t h e r eq u ir ed efficien cy. RGF F ca n b e con s id er ed com p et it ive w it h E SP on ly a t h igh r esist iv it y a n d m ay r es u lt in b ein g con -ven ien t a t h igh efficien cy. In t h e com p a r ison of con ven t ion a l E SP w it h RGF F a n d P J F F su ch r esu lt s a r e in a ccor d a n ce w it h t h ose of ea r lier s t u d ies (E P RI, 1985, 1992c; Sloa t et a l., 1993), even if t h e n u m er ica l r esu lt s a r e n ot d ir ect ly com p a r a ble d u e t o d iffer en ces in t h e a ssu m ed econ om ic p r em is es; m or eover, som e p ieces of eq u ip m en t a n d a n n u a l cost s h ave h er e b een n e glect ed , b ein g com m on t o a ll k in d s of d ev ices.
In t h e p r esen t a n a ly sis t h e cost eva lu a t ion h a s b een p er for m ed on t h e b a sis of aver a ge or t y p ica l va lu es of t h e op er a t in g p a r a m et er s. H ow ever, p r esen t r esu lt s a r e in d ica t ive a n d va lid on ly u n d er t h e p r ev iou sly st a t ed a ssu m p t ion s. In fa ct , s it e sp ecifi c con d it ion s m ay h eav ily m od ify t h e econ om ic com p a r i-son lea d in g t o va lu es of t h e d esign p a r a m e-t er s su b se-t a n e-t ia lly d iffer en e-t fr om e-t h ose a ssu m ed . As a n exa m p le, F igu r e 5 sh ow s t h e w id e TAC r a n ge t h a t ca n ch a r a ct er ize F F. Up p er a n d low er b ou n d s of t h e sh a d ed a r ea r e p r esen t t h e ca s es of p essim ist ic a n d op t i-m ist ic d esign . For t h e sa k e of sii-m p licit y on ly t h e follow in g p a r a m et er s’ va r ia t ion s h ave b een con sid er ed (Belb a et a l., 1992; Dea n a n d Cu sh in g, 1988; E P RI, 1992b ): t u b esh eet p r es-su r e d r op (P J F F : 480 t o 2910P a ; RGF F : 890 t o 1970P a ; SF F : 1060 t o 1970P a ), a ir -clot h r a t io (P J F F : 0.015 t o 0.03m / s; RGF F : 0.007 t o 0.011m / s; SF F : 0.012 t o 0.016m / s ), a n d b a g life (P J F F : 1 t o 5 yea r s; RGF F : 3 t o 5 yea r s; SF F : 2 t o 4 yea r s), w h ile t h e p ossible va r ia t ion of fa b r ic m a t er ia l a n d t h e va r ia t ion of it s sp e-cifi c cost w it h b a gs d im en sion s a n d life h ave b een n e glect ed . Mor eover, in P J F F t h e sp e-cifi c com p r essed a ir con su m p t ion h a s n ot b een cor r ela t ed w it h aver a ge t u b esh eet p r es-su r e d r op n or h a s t h e effect of clea n in g p u lse p r ess u r e b een con sid er ed .
F in a lly, t h e p r op er t ies of bu r n ed coa l h eav -ily in fl u en ce t h e ch oice of t h e con t r ol d ev ice for a given b oiler size. As a n a p p lica t ion exa m p le of t h e m a p p in g r esu lt in g fr om t h e p r esen t st u dy, t h e ca se of a 250MW b oiler fi r in g t h r ee d iffer en t coa ls is p r esen t ed . T h e ca lcu la t ed va lu es of Ta ble I sh ow h ow t h e econ om ic ch oice is d ict a t ed by sp ecifi c op er -a t in g con d it ion s. Co-a l -a n d b oiler ch -a r -a ct er is-t ics h ave b een ob is-t a in ed by liis-t er a is-t u r e d a is-t a (E P RI, 1985, 1992c). T h e cos t va lu es m ay b e a lso eva lu a t ed by d ir ect in s p ect ion of fi gu r es a n a logou s t o t h e p r ev iou s on es, bu t com p u t ed for t h e r eq u ir ed E SP efficien cy a n d r esist iv -it y, en t er in g w -it h t h e p r op er fl ow r a t e. TAC va lu es sh ow n in Ta ble I sh ow t h a t for a low r esis t iv it y coa l lik e N or t h Da k ot a lign it e, t h e con ven ien t ch oice is a con ven t ion a l E SP even Figure 4
Anto nio C. Caputo and Pac ific o M. Pe lagagge Ec o no mic c o mpariso n o f pulse d e le c tro static pre c ipitato rs and fabric filte rs in c o al-fire d utility plants Enviro nme ntal Manage me nt and He alth
1 0 / 2 [1 9 9 9 ] 9 6 –1 0 4
in sp it e of t h e h igh efficien cy r eq u ir ed . For a m ed iu m r esist iv it y coa l in s t ea d (Ap p a la ch ia n low su lfu r ) a p u ls ed E SP (or a n SF F ) wou ld b e p r efer a ble even if a low er collect ion
efficien cy is r eq u est ed . F in a lly, in ca se of h igh r esis t iv it y d u st (Wyom in g P ow d er River Ba sin coa l) t h e low est cost op t ion wou ld b e a n SF F, w it h p u lsed E SP a n d P J F F s h ow in g sim ila r bu t h igh er t ot a l cos t s.
Conclusions
In t h is p a p er a n econ om ica l com p a r ison b et w een p u lsed E SP a n d con ven t ion a l E SP, r ever se a ir, sh a k er, a n d p u lse-jet fa b r ic fi lt er s h a s b een ca r r ied ou t in t h e coa l-fi r ed b oiler a r ea . In t h e ca se of low r esist iv it y d u st , cor r e-sp on d in g t o h igh su lfu r coa ls, con ven t ion a l E SP r esu lt s econ om ica lly con ven ien t w it h r es p ect t o F F esp ecia lly w h en t h e ga s fl ow r a t e in cr ea ses. T h is is fu r t h er con fi r m ed con sid er in g r ed u ced d u st loa d in g of t h e st r ea m , giv in g r is e t o low er d esign collect ion efficien cy. For m ed iu m r esist iv it y coa l, eco-n om ic coeco-n veeco-n ieeco-n ce of p u lsed E SP h a s b eeeco-n p oin t ed ou t . Als o in t h is con d it ion , con ve-n ieve-n ce of p u lsed E SP im p r oves w h eve-n d u st loa d in g d ecr ea ses a n d ga s fl ow r a t e gr ow s. Wh en low s u lfu r coa ls a r e bu r n ed t h e r esu lt -in g h igh r esis t iv it y d u st d efi n it ively p en a l-izes t h e con ven t ion a l E SP. F F sh ow gen er a lly b et t er econ om ic r esu lt s, w it h t h e exce p t ion of RGF F, even w h en com p a r ed t o p u lsed E SP a t lea st a s lon g a s h igh efficien cy is r eq u est ed a n d F F p er for m a ccor d in g t o d esign sp ecifi ca -t ion s. F r om -t h is p oin -t of v iew fu r -t h er
r es ea r ch effor t s h ave t o b e a im ed a t t h e a n a ly sis of coa l coh esiv it y effect s on F F p er for -m a n ces a n d cos t s.
References
Belb a , V.H ., Gr u bb, V.T. a n d Ch a n g, R.L. (1992), “T h e p ot en t ia l of p u lse-jet b a gh ou ses for u t ilit y b oiler s. P a r t 1”, J ou r n a l of th e A ir
Wa ste M a n a gem en t A ssocia tion , Vol. 42 N o. 2,
p p. 209-217.
Bick elh a u p t , R.E . (1975), “E ffect of ch em ica l com -p osit ion on su r fa ce r esist iv it y of fl y a s h ”, E PA r e p or t 600/ 2-75-017.
Figure 5
Fabric filte rs to tal annual c o st range : (a) re ve rse air, (b) shake r, (c ) pulse je t
Table I
Influe nc e o f c o al c harac te ristic s
Dust load Flow rate ESP Resistivity SCA(c) SCA(p) Total annual cost ($M / year) Coal type (g/ m3) (m3/ s) efficiency (ohm cm) (s/ m) (s/ m) ESP(c) ESP(p) PJFF RGFF SFF North Dakota
lignite 6 .1 3 5 3 7 .5 0 .9 9 5 1 1 ×1 09 5 6 .5 5 6 .5 2 .6 3 2 .7 7 2 .9 8 3 .4 0 2 .7 7
Appalachian
low sulfur 3 .9 8 4 1 2 .9 0 .9 9 2 4 1 ×1 01 1 6 1 .4 5 2 .4 2 .2 4 2 .0 7 2 .3 3 3 .1 0 2 .0 9 Wyoming
Anto nio C. Caputo and Pac ific o M. Pe lagagge Ec o no mic c o mpariso n o f pulse d e le c tro static pre c ipitato rs and fabric filte rs in c o al-fire d utility plants Enviro nme ntal Manage me nt and He alth
1 0 / 2 [1 9 9 9 ] 9 6 –1 0 4
Bu sh , P.V., Sn yd er, T.R. a n d Ch a n g, R.L. (1986),
J ou r n a l of th e A ir Pollu tion Con tr ol A ssocia -tion , Vol. 39 N o. 228.
Ca p u t o, A.C. a n d P ela ga gge, P.M . (1997),
“E con om ic a n a ly sis of p u lsed v s con ven t ion a l E SP s in in d u st r ia l a p p lica t ion s ”,
E n v ir on m en ta l M a n a gem en t a n d H ea lth , Vol.
8 N o. 3, p p. 100-4.
Dea n , A.H . a n d Cu sh in g, K.M . (1988), “Su r vey on t h e u se of p u lse-jet fa b r ic fi lt er s for coa l-fi r ed u t ilit y a n d in d u st r ia l b oiler s ”, J ou r n a l of th e
A ir Pollu tion Con tr ol A ssocia tion , Vol. 38 N o.
1, p p. 90-6.
E lect r ic P ow er Resea r ch In s t it u t e (1986), A n In v
es-tiga tion of Precip ita tor Pu lse E n ergiz a tion ,
E P RI CS-4717.
E n v ir on m en t a l P r ot ect ion Agen cy (1987), E
co-n om ic A co-n a lysis B ra co-n ch Coco-n tr ol Cost M a co-n u a l,
E PA 450/ 5-87-001A (P B87-166583).
Felix, L.G., Mer r it t , R.L. a n d Du n ca n , W.S. (1986),
J ou r n a l of th e A ir Pollu tion Con tr ol A ssocia -tion , Vol. 36, N o. 1075.
H a ll, H .J . (1990), “H ist or y of p u ls e en er giza t ion in elect r ost a t ic p r ecip it a t ion ”, J ou r n a l of
E lectr osta tics, Vol. 25, p p. 1-22.
La u sen , P. (1990), “Ap p lica t ion of p u ls e en er giza -t ion on elecr os-t a -t ic p r ecip i-t a -t or s for va r iou s p r ocesses”, J ou r n a l of E lectr osta tics, Vol. 25, p p. 41-53.
Ma t t s, S. a n d Oh n feld t , P.O. (1973), “E fficien t ga s clea n in g w it h SF elect r os t a t ic p r ecip it a t or s ”,
A B S v en sk a Fla k t T ech . B u ll.
N elson , J .K. a n d Sa la soo, L. (1987), “T h e im p a ct of p u lse en er giza t ion on elect r os t a t ic p r ecip it a -t ion p er for m a n ce”, IE E E T r. on E lec-tr ica l
In su la tion , Vol. E I-22 N o. 6, p p. 657-75.
P ela ga gge, P.M., Ca p u t o, A.C. a n d Gia cch et t a , G. (1996), “E con om ic im p a ct of elect r os t a t ic
p r ecip it a t or s p u lse en er giza t ion on d ed u s t in g in ir on -or e sin t er in g p la n t s”, E n v ir on m en ta l
M a n a gem en t a n d H ea lth , Vol. 7 N o. 5, p p. 21-6.
Tu r n er, J .H ., Vin er, A.S., McKen n a , J .D., J en k in s, R.E . a n d Va t av u k , W.M. (1987), “Sizin g a n d cost in g of fa b r ic fi lt er s ”, J ou r n a l of th e A ir
Pollu tion Con tr ol A ssocia tion , Vol. 37, P a r t 1:
N o. 6, p p. 749-59; P a r t 2: N o. 9, p p. 1105-12. Tu r n er, J .H ., Law less, P.A., Ya m a m ot o, T., Coy,
D.W., Gr ein er, G.P., McKen n a , J .D. a n d Va t av u k , W.M. (1988), “Sizin g a n d cost in g of elect r os t a t ic p r ecip it a t or s”, J ou r n a l of th e A ir
Pollu tion Con tr ol A ssocia tion , Vol. 38, P a r t 1:
N o. 4, p p. 459-72; P a r t 2: N o. 5, p p. 715-26. Va t av u k , W.M. (1990), E stim a tin g costs of A ir
Pol-lu tion Con tr ol, Lew is P u blis h er s, Ch elsea , MI.
Further reading
E lect r ic P ow er Resea r ch In st it u t e (1985), E con om
ics of Fab r ic Filters a n d E lectr osta tic Precip ita -tors – 1984, E P RI CS-4083.
E lect r ic P ow er Resea r ch In st it u t e (1992a ), Fab r ic
Filters for th e E lectr ic Utility In d u str y – Vol. 1: Gen era l Con cep ts, E P RI CS-5161.
E lect r ic P ow er Resea r ch In st it u t e (1992b ), Fab r ic
Filters for th e E lectr ic Utility In d u str y – Vol. 5: Gu id elin es for Fab r ic Filter Design , E P RI
CS-5161.
E lect r ic P ow er Resea r ch In st it u t e (1992c), E
con om ic E v a lu a tiocon of Pa r ticu la te Cocon tr ol T ech -n ologies: N ew U-n its, E P RI TR-100748.
Sloa t , D.G., Ga ik w a d , R.P. a n d Ch a n g, R.L. (1993), “T h e p ot en t ia l of p u lse-jet b a gh ou ses for u t ilit y b oiler s. P a r t 3: com p a r a t ive econ om ics of p u lse-jet b a gh ou se, p r ecip it a t or s a n d r ever s e-ga s b a gh ou ses”, J ou r n a l of th e A ir
Wa ste M a n a gem en t A ssocia tion , Vol. 43 N o. 1,
