ash handling plant & esp

8/13/2019 Ash Handling Plant & ESP

1/32

1. WHAT ARE THE P R E C A U T I O N S TO BE TAKEN W H I L E

ENTERING INTO ELECTROSTATIC PRECIPITATOR?

Ans:1. All voltages shall be considered dangerous even though voltage

may not be high enough to produce severe shock (80V onwards).

2. All electrical circuits are to be treated as live and no work i.e.

maintenance repairs cleaning etc is to be carried out on any part o! the

apparatus unless "

# $uch parts are dead i.e. totally de"energi%ed.

# &solated and all steps taken to lock o!! !rom live conductors.

# '!!ectively earthed.

# eleased to work by issuing work permit by authori%ed person.

# on!irmation !or de"energisation is received.

*. Visitors + unauthori%ed persons should not be allowed to touch or

handle electrical apparatus or come in danger %one o! high voltage

e,uipment.

-. oose clothing metal (straps) watch rings chains etc. should be

avoided.

/. aste causes many accidents be sure o! what you are doing.


2/32

. se grounding chains whenever entering the precipitator 3"

switch enclosure or bus ducts. 3he precipitator can hold a high static

charge up to 1/ kV a!ter it is de"energi%ed. 3he only sa!e ground is

one that can be seen.

4. 5ever open a hopper door unless the dust level is positively below

the door. 6o not trust the level alarm. heck !rom the upper access in

the precipitator. ot dust can !low like water and severely burn or kill a

person standing below the door. 7ear protective clothing.

8. e on !irm !ooting prior to entering the precipitator. lear all trip

ha%ards. se the back o! the hand to test !or high metal temperatures.

9. Avoid o%one inhalation. :%one is created any time the discharge

electrodes are energi%ed. 7ear an air"line mask when entering the

precipitator !lues or stack when o%one may be present. 6o not use

!ilters cartridge or canister respirators.

10. 5ever poke hoppers with an uninsulated metal bar. ;eep sa!ety and

danger signs in place. lean bright signs are obeyed more than

deteriorated signs.


3/32

Principles of Electrostatic precipitator

Electrostatic precipitatio is a !et"o# o$ #%st collectio t"at %ses

electrostatic $orces& a# cosists o$ #isc"ar'e (ires a# collecti'

plates. A "i'" )olta'e is applie# to t"e #isc"ar'e (ires to $or! a

electrical $iel# *et(ee t"e (ires a# t"e collecti' plates& a# also

ioi+es t"e 'as aro%# t"e #isc"ar'e (ires to s%ppl, ios. W"e 'as

t"at cotais a aerosol -#%st& !ist $lo(s *et(ee t"e collecti'

plates a# t"e #isc"ar'e (ires& t"e aerosol particles i t"e 'as are

c"ar'e# *, t"e ios. T"e Co%lo!* $orce ca%se# *, t"e electric $iel#

ca%ses t"e c"ar'e# particles to *e collecte# o t"e collecti' plates&

a# t"e 'as is p%ri$ie#. T"is is t"e priciple o$ electrostatic

precipitatio& a# Electrostatic precipitator appl, t"is priciple o ai#%strial scale. T"e particles collecte# o t"e collecti' plates are

re!o)e# *, !et"o#s s%c" as -1 #islo#'i' *, rappi' t"e collecti'

plates& -/ scrapi' o$$ (it" a *r%s"& or -0 (as"i' o$$ (it" (ater&

a# re!o)i' $ro! a "opper.

ia'ra! o$ t"e priciple o$ electrostatic precipitatio

Dust collection efficiency and electrical resistivity of dust


4/32

T"e #%st collectio e$$iciec, o$ Electrostatic precipitator is a$$ecte#

*, t"e electrical resisti)it, o$ t"e #%st collecte#.

I t"e or!al resisti)it, area& t"e #%st collectio e$$iciec, is "i'"& so

#%st collectio is sta*le. 2ost o$ t"e aerosols "a#le# *, Electrostaticprecipitator are i t"is electrical resisti)it, area.

Particles i t"e lo(3resisti)it, area lose t"eir c"ar'e as soo as t"e,

arri)e at t"e collecti' plate& so t"e, are re3etraie# i t"e #%st

collectio area& a# t"e #%st collectio e$$iciec, is 'reatl, re#%ce#.

-Re3etrai!et

T"e #%st collectio e$$iciec, i t"e "i'"3resisti)it, area re#%ces as

t"e electrical resisti)it, o$ t"e #%st icreases. Also& partial #isc"ar'e

occ%rs (it"i t"e #%st la,er collecte# o t"e collecti' plates& a# as a

res%lt $las"o)ers $re4%etl, occ%r& t"e applie# )olta'e is re#%ce#& a#

t"e #isc"ar'e c%rret is re#%ce#. I$ t"e electrical resisti)it, o$ t"e #%st

is $%rt"er icrease#& t"e #isc"ar'e c%rret icreases a*or!all,& a#

t"e applie# )olta'e is re#%ce# -*ac5 coroa p"eo!eo. T"e

!o)i'3electro#e t,pe electrostatic precipitator (e #e)elope# is

s%ita*le $or "i'"3per$or!ace collectio o$ "i'"3resisti)it, #%st.

T"ere$ore& a i!portat $actor ("e plai' Electrostatic precipitator

is t"e electrical resisti)it, o$ t"e #%st to *e collecte#.


5/32

pa'e top

Dust collection efficiency and particle size distribution

T"e #%st collectio e$$iciec, o$ Electrostatic precipitator is a$$ecte#

*, t"e particle si+e o$ t"e aerosol -#%st& !ist to *e collecte#. T"e

t"eoretical !i'ratio )elocit, at ("ic" a particle #ia!eter o$ se)eral

6! !o)es to(ar#s t"e collecti' plate is al!ost #irectl, proportioal

to t"e particle #ia!eter. W"e #%st collectio is per$or!e# o aaerosol (it" #i$$eret si+e particles %si' a electrostatic precipitator&

t"e collectio e$$iciec, is "i'" $or t"e lar'e particles& a# lo( $or t"e

s!all particles.

To o*tai t"e sa!e #%st collectio e$$iciec, $or a aerosol (it" s!all

particle si+e& t"e electrostatic precipitator !%st *e lar'er -to icrease

t"e treati' ti!e it ta5es $or t"e process 'as to pass t"ro%'" t"a t"at

o$ lar'e3si+e particles. T"ere$ore& t"e particle si+e #istri*%tio o$ t"eaerosol to *e collecte# is a i!portat $actor ("e plai' a

electrostatic precipitator.

Relationship between electrostatic precipitator collection

efficiency and the particle size
http://www.hitachi-pt.com/products/energy/dustcollection/principle/dustcollection.html#tophttp://www.hitachi-pt.com/products/energy/dustcollection/principle/dustcollection.html#top


6/32

pa'e top

Dust collection efficiency and aerosol concentration

T"e #%st collectio e$$iciec, o$ a electrostatic precipitator is 'reatl,

a$$ecte# *, t"e cocetratio i t"e 'as o$ t"e aerosol -#%st& !ist to

*e collecte#. 7or t"e sa!e re4%ire# )al%e o$ aerosol cocetratio at

t"e o%tlet o$ t"e electrostatic precipitator& t"e "i'"er t"e aerosol

cocetratio at t"e ilet& t"e lo'er t"e treat!et ti!e o$ t"e 'as i

t"e electrostatic precipitator& a# t"e lar'er t"e #e)ice.

Also& i$ t"e ilet aerosol cocetratio is "i'" a# t"e cotet o$ $ie

particles s!aller t"a se)eral 6! is "i'"& i or#er to create a c"ar'e

clo%# o$ c"ar'e# $ie particles *et(ee t"e #isc"ar'e (ires a# t"e

collecti' plates& t"e coroa #isc"ar'e $ro! t"e #isc"ar'e (ires is

re#%ce#& also re#%ci' t"e #%st collectio e$$iciec, -space c"ar'i'

e$$ect.

T"e aerosol cocetratio at t"e electrostatic precipitator ilet a# t"ere4%ire# o%tlet cocetratio are i!portat $actors ("e plai' a

electrostatic precipitator.

Introduction to Precipitators

A electrostatic precipitator is a lar'e& i#%strial e!issio3cotrol

%it. It is #esi'e# to trap a# re!o)e #%st particles $ro! t"e e8"a%st

'as strea! o$ a i#%strial process. Precipitators are %se# i t"esei#%stries9

Po(er:Electric

Ce!et

C"e!icals

2etals
http://www.hitachi-pt.com/products/energy/dustcollection/principle/dustcollection.html#tophttp://www.hitachi-pt.com/products/energy/dustcollection/principle/dustcollection.html#top


7/32

Paper

I !a, i#%strial plats& partic%late !atter create# i t"e i#%strial

process is carrie# as #%st i t"e "ot e8"a%st 'ases. T"ese #%st3la#e

'ases pass t"ro%'" a electrostatic precipitator t"at collects !ost o$t"e #%st. Cleae# 'as t"e passes o%t o$ t"e precipitator a# t"ro%'" a

stac5 to t"e at!osp"ere. Precipitators t,picall, collect ;;.;< or !ore

o$ t"e #%st $ro! t"e 'as strea!.

Precipitators $%ctio *, electro staticall, c"ar'i' t"e #%st particles

i t"e 'as strea!. T"e c"ar'e# particles are t"e attracte# to a#

#eposite# o plates or ot"er collectio #e)ices. W"e eo%'" #%st "as

acc%!%late#& t"e collectors are s"a5e to #islo#'e t"e #%st& ca%si' itto $all (it" t"e $orce o$ 'ra)it, to "oppers *elo(. T"e #%st is t"e

re!o)e# *, a co)e,or s,ste! $or #isposal or rec,cli'.

epe#i' %po #%st c"aracteristics a# t"e 'as )ol%!e to *e treate#&

t"ere are !a, #i$$eret si+es& t,pes a# #esi's o$ electrostatic

precipitators. =er, lar'e po(er plats !a, act%all, "a)e !%ltiple

precipitators $or eac" %it.

Basic Principles

Electrostatic precipitatio re!o)es particles $ro! t"e e8"a%st 'as

strea! o$ a i#%strial process. O$te t"e process i)ol)es

co!*%stio& *%t it ca *e a, i#%strial process t"at (o%l# ot"er(ise

e!it particles to t"e at!osp"ere. Si8 acti)ities t,picall, ta5e place9

Ioi+atio 3 C"ar'i' o$ particles

2i'ratio 3 Trasporti' t"e c"ar'e# particles to t"e collecti'

s%r$aces

Collectio 3 Precipitatio o$ t"e c"ar'e# particles oto t"ecollecti' s%r$aces

C"ar'e issipatio 3 Ne%trali+i' t"e c"ar'e# particles o t"e

collecti' s%r$aces

Particle islo#'i' 3 Re!o)i' t"e particles $ro! t"e collecti'

s%r$ace to t"e "opper


8/32

Particle Re!o)al 3 Co)e,i' t"e particles $ro! t"e "opper to a

#isposal poit

T"e !a>or precipitator co!poets t"at acco!plis" t"ese acti)ities are

as $ollo(s9

isc"ar'e Electro#es Po(er Co!poets

Precipitator Cotrols

Rappi' S,ste!s

P%r'e Air S,ste!s

7l%e Gas Co#itioi'

Design & Performance Requirements

esi'i' a precipitator $or opti!%! per$or!ace re4%ires proper

si+i' o$ t"e precipitator i a##itio to opti!i+i' precipitator

e$$iciec,. W"ile so!e %sers rel, o t"e precipitator !a%$act%rer to

#eter!ie proper si+i' a# #esi' para!eters& ot"ers c"oose to eit"er

ta5e a !ore acti)e role i t"is process or "ire o%tsi#e e'ieeri'

$ir!s.

Precipitator per$or!ace #epe#s o its si+e a# collecti' e$$iciec,.

I!portat para!eters icl%#e t"e collecti' area a# t"e 'as )ol%!e to

*e treate#. Ot"er 5e, $actors i precipitator per$or!ace icl%#e t"e

electrical po(er ip%t a# #%st c"e!istr,.

Precipitator si+i'

T"e si+i' process is co!ple8 as eac" precipitator !a%$act%rer "as a

%i4%e !et"o# o$ si+i'& o$te i)ol)i' t"e %se o$ co!p%ter !o#els

a# al(a,s i)ol)i' a 'oo# #ose o$ >%#'!et. No co!p%ter !o#elo its o( ca assess all t"e )aria*les t"at a$$ect precipitator

per$or!ace.

Collecti' E$$iciec,

Base# o speci$ic 'as )ol%!e a# #%st loa#& calc%latios are %se# to
http://www.neundorfer.com/FileUploads/RichTextboxImages/Flash/powersystemcomp.swfhttp://www.neundorfer.com/FileUploads/RichTextboxImages/Flash/powersystemcomp.swf


9/32

pre#ict t"e re4%ire# si+e o$ a precipitator to ac"ie)e a #esire#

collecti' e$$iciec,.

Po(er Ip%t

Po(er ip%t is co!prise# o$ t"e )olta'e a# c%rret i a electrical

$iel#. Icreasi' t"e po(er ip%t i!pro)es precipitator collecti'e$$iciec, %#er or!al co#itios.

Process ariables Gas c"aracteristics a# particle properties #e$ie

"o( (ell a precipitator (ill (or5 i a 'i)e applicatio. T"e !ai

process )aria*les to cosi#er are9

Gas $lo( rate

T"e 'as $lo( rate i a po(er plat is #e$ie# *, coal 4%alit,& *oilerloa#& e8cess air rate a# *oiler #esi'. W"ere t"ere is o co!*%stio&

t"e 'as $lo( rate (ill "a)e process3speci$ic #eter!iats.

Particle si+e a# si+e #istri*%tio

T"e si+e #istri*%tio i a po(er plat is #e$ie# *, coal 4%alit,& t"e

coal !ill setti's a# *%rer #esi'. Particle si+e $or o3co!*%stio

processes (ill "a)e si!ilar #eter!iats.

Particle resisti)it,

T"e resisti)it, o$ $l, as" or ot"er particles is i$l%ece# *, t"e

c"e!ical co!positio a# t"e 'as te!perat%re.

Gas te!perat%re

7ollo(i' are #etails o$ t"ese process )aria*les9

1. Gas 7lo( Rate

A precipitator operates *est (it" a 'as )elocit, o$ 0. 3 . $t:sec. At

"i'"er )elocit,& particle re3etrai!et icreases rapi#l,. I$ )elocit, istoo lo(& per$or!ace !a, s%$$er $ro! poor 'as $lo( #istri*%tio or

$ro! particle #ropo%t i t"e #%ct(or5.

/. Particle Si+e

A precipitator collects particles !ost easil, ("e t"e particle si+e is

coarse. T"e 'eeratio o$ t"e c"ar'i' coroa i t"e ilet $iel# !a, *e


10/32

s%ppresse# i$ t"e 'as strea! "as too !a, s!all particles -less t"a 1

6!.

=er, s!all particles -@./ 3 @.6! are t"e !ost #i$$ic%lt to collect

*eca%se t"e $%#a!etal $iel#3c"ar'i' !ec"ais! is o)er("el!e#

*, #i$$%sio c"ar'i' #%e to ra#o! collisios (it" $ree ios.0. Particle Resisti)it,

Resisti)it, is resistace to electrical co#%ctio. T"e "i'"er t"e

resisti)it,& t"e "ar#er it is $or a particle to tras$er its electrical c"ar'e.

Resisti)it, is i$l%ece# *, t"e c"e!ical co!positio o$ t"e 'as

strea!& particle te!perat%re a# 'as te!perat%re. Resisti)it, s"o%l# *e

5ept i t"e ra'e o$ 1@ 3 1@1@ o"!3c!.

Hi'" resisti)it, ca re#%ce precipitator per$or!ace. 7or e8a!ple& ico!*%stio processes& *%ri' re#%ce#3s%l$%r coal icreases

resisti)it, a# re#%ces t"e collecti' e$$iciec, o$ t"e precipitator.

So#i%! a# iro o8i#es i t"e $l, as" ca re#%ce resisti)it, a#

i!pro)e per$or!ace& especiall, at "i'"er operati' te!perat%res.

O t"e ot"er "a#& lo( resisti)it, ca also *e a pro*le!. 7or e8a!ple

-i co!*%stio processes& %*%re# car*o re#%ces precipitator

per$or!ace *eca%se it is so co#%cti)e a# loses its electrical c"ar'e

so 4%ic5l, t"at it is easil, re3etraie# $ro! t"e collecti' plate.

. Gas Te!perat%re

T"e e$$ect o$ 'as te!perat%re o precipitator collecti' e$$iciec,&

'i)e its i$l%ece o particle resisti)it,& ca *e si'i$icat.

. Iteractios to Cosi#er

Particle si+e #istri*%tio a# particle resisti)it, a$$ect t"e co"esi)eess

o$ t"e la,er o$ precipitate# !aterial o t"e collecti' plates a# t"e

a*ilit, o$ t"e rappi' s,ste! to #islo#'e t"is la,er $or trasport itot"e precipitator "opper (it"o%t e8cessi)e re3etrai!et.

!bout Discharge Electrodes -Bac5 to top

isc"ar'e electro#es e!it c"ar'i' c%rret a# pro)i#e )olta'e t"at

'eerates a electrical $iel# *et(ee t"e #isc"ar'e electro#es a# t"e
http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#tophttp://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#top


11/32

collecti' plates. T"e electrical $iel# $orces #%st particles i t"e 'as

strea! to !i'rate to(ar# t"e collecti' plates. T"e particles t"e

precipitate oto t"e collecti' plates. Co!!o t,pes o$ #isc"ar'e

electro#es icl%#e9

Strai'"t ro%# (ires T(iste# (ire pairs

Bar*e# #isc"ar'e (ires

Ri'i# !asts

Ri'i# $ra!es

Ri'i# spi5e# pipes

Spiral (ires

isc"ar'e electro#es are t,picall, s%pporte# $ro! t"e %pper #isc"ar'e

$ra!e a# are "el# i ali'!et *et(ee t"e %pper a# lo(er

#isc"ar'e $ra!es. T"e %pper #isc"ar'e $ra!e is i t%r s%pporte# $ro!

t"e roo$ o$ t"e precipitator casi'. Hi'"3)olta'e is%lators are

icorporate# ito t"e s%pport s,ste!. I (ei'"te# (ire s,ste!s& t"e

#isc"ar'e electro#es are "el# ta%t *, (ei'"ts at t"e lo(er e# o$ t"e

(ires.

!bout "ollecting Plates -Bac5 to top

Collecti' plates are #esi'e# to recei)e a# retai t"e precipitate#

particles %til t"e, are itetioall, re!o)e# ito t"e "opper.

Collecti' plates are also part o$ t"e electrical po(er circ%it o$ t"e

precipitator. T"ese collecti' plate $%ctios are icorporate# ito t"e

precipitator #esi'. Plate *a$$les s"iel# t"e precipitate# particles $ro!

t"e 'as $lo( ("ile s!oot" s%r$aces pro)i#e $or "i'" operati' )olta'e.

Collecti' plates are s%spe#e# $ro! t"e precipitator casi' a# $or!t"e 'as passa'es (it"i t"e precipitator. W"ile t"e #esi' o$ t"e

collecti' plates )aries *, !a%$act%rer& t"ere are t(o co!!o

#esi's9

Plates s%pporte# $ro! a)il *ea!s at eit"er e#

T"e a)il *ea! is also t"e poit o$ i!pact $or t"e collecti' rapper


12/32

Plates s%pporte# (it" "oo5s #irectl, $ro! t"e precipitator casi'

T(o or !ore collecti' plates are coecte# at or ear t"e ceter *,

rapper *ea!s& ("ic" t"e ser)e as i!pact poits $or t"e rappi'

s,ste!

Top& ceter& or *otto! spacer *ars !a, *e %se# to !aitai collecti'

plate ali'!et a# s%stai electrical clearaces to t"e #isc"ar'e

s,ste!.

!bout Power #upplies and "ontrols -Bac5 to top

T"e po(er s%ppl, s,ste! is #esi'e# to pro)i#e )olta'e to t"e

electrical $iel# -or *%s sectio at t"e "i'"est possi*le le)el. T"e

)olta'e !%st *e cotrolle# to a)oi# ca%si's%staie# arci' or spar5i' *et(ee t"e electro#es

a# t"e collecti' plates.

Clic5 "ere to )ie( aprecipitator po(er

s,ste!ai!ate# sc"e!atic s"o(i' represetati)e

co!poets.

Electricall,& a precipitator is #i)i#e# ito a 'ri#&

(it" electrical $iel#s i series -i t"e #irectio o$ t"e

'as $lo( a# oe or !ore *%s sectios i parallel

-cross3(ise to t"e 'as $lo(. W"e electrical $iel#s are i series& t"e

po(er s%ppl, $or eac" $iel# ca *e a#>%ste# to opti!i+e operatio o$

t"at $iel#. Li5e(ise& "a)i' !ore t"a oe electrical *%s sectio i

parallel allo(s a#>%st!ets to co!pesate $or t"eir #i$$ereces& so t"at

po(er ip%t ca *e opti!i+e#. T"e po(er s%ppl, s,ste! "as $o%r

*asic co!poets9

A%to!atic )olta'e cotrol

Step3%p tras$or!er

Hi'"3)olta'e recti$ier

Sesi' #e)ice
http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#tophttp://www.neundorfer.com/FileUploads/RichTextboxImages/Flash/powersystemcomp.swfhttp://www.neundorfer.com/FileUploads/RichTextboxImages/Flash/powersystemcomp.swfhttp://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#tophttp://www.neundorfer.com/FileUploads/RichTextboxImages/Flash/powersystemcomp.swfhttp://www.neundorfer.com/FileUploads/RichTextboxImages/Flash/powersystemcomp.swf


13/32

1. =olta'e cotrol

A%to!atic )olta'e cotrol )aries t"e po(er to t"e tras$or!er3recti$ier

i respose to si'als recei)e# $ro! sesors i t"e precipitator a# t"e

tras$or!er3recti$ier itsel$. It !oitors t"e electrical co#itios isi#e

t"e precipitator& protects t"e iteral co!poets $ro! arc3o)er#a!a'es& a# protects t"e tras$or!er3recti$ier a# ot"er co!poets

i t"e pri!ar, circ%it.

T"e i#eal a%to!atic )olta'e cotrol (o%l# pro#%ce t"e !a8i!%!

collecti' e$$iciec, *, "ol#i' t"e operati' )olta'e o$ t"e

precipitator at a le)el >%st *elo( t"e spar53o)er )olta'e. Ho(e)er& t"is

le)el caot *e ac"ie)e# 'i)e t"at co#itios c"a'e $ro! !o!et to

!o!et. Istea#& t"e a%to!atic )olta'e cotrol icreases o%tp%t $ro!t"e tras$or!er3recti$ier %til a spar5 occ%rs. T"e t"e cotrol resets to

a lo(er po(er le)el& a# t"e po(er icreases a'ai %til t"e e8t spar5

occ%rs.

!utomatic oltage "ontrollers-$or Electrostatic Precipitators

A electroic #e)ice %se# to cotrol t"e applicatio o$ .C. po(er

ito a $iel# o$ a electrostatic precipitator. -PIC O7 2=C 7ACE

PANEL AN PIC O7 INTER7ACE BOAR

$heory

Optimize power applicationD T"e pri!ar, p%rpose o$ a )olta'e

cotroller is to #eli)er as !%c" %se$%l electrical po(er to t"e

correspo#i' electrostatic precipitator $iel#-s as possi*le. T"is is ot

a eas, >o* electrical c"aracteristics i t"e $iel#-s are costatl,

c"a'i'& ("ic" is (", a )olta'e cotroller is re4%ire#. Spark reactionD W"e t"e )olta'e applie# to t"e electrostatic

precipitator $iel# is too "i'" $or t"e co#itios at t"e ti!e& a spar5 o)er

-or coroa #isc"ar'e (ill occ%r. etri!etall, "i'" a!o%ts o$

c%rret ca occ%r #%ri' a spar5 o)er i$ ot properl, cotrolle#& ("ic"

co%l# #a!a'e t"e $iel#s. A )olta'e cotroller (ill !oitor t"e pri!ar,
http://en.wikipedia.org/wiki/Electrostatic_precipitatorhttp://en.wikipedia.org/wiki/Corona_dischargehttp://en.wikipedia.org/wiki/Electrostatic_precipitatorhttp://en.wikipedia.org/wiki/Corona_discharge


14/32

a# seco#ar, )olta'e a# c%rret o$ t"e circ%it& a# #etect a spar5

o)er co#itio. Oce #etecte#& t"e po(er applie# to t"e $iel# (ill *e

i!!e#iatel, c%t o$$ or re#%ce#& ("ic" (ill stop t"e spar5. A$ter a

s"ort a!o%t o$ ti!e t"e po(er (ill *e ra!pe# *ac5 %p& a# t"e

process (ill start o)er.Protect system components by adhering to component limitationsD

T"e Tras$or!er Recti$ier set -TR set ca *e #a!a'e# *, e8cessi)e

a!o%ts o$ c%rret or )olta'e $lo(i' t"ro%'" it. Eac" TR set "as

)olta'e a# c%rret li!its esta*lis"e# *, t"e !a%$act%rer& ("ic" are

la*ele# o a attac"e# a!eplate -PIC O7 A NA2EPLATE. T"ese

a!eplate li!it )al%es -t,picall, pri!ar, a# seco#ar, c%rret& a#

)olta'e are pro'ra!!e# ito t"e )olta'e cotroller. T"ro%'"!eteri' circ%its& t"e )olta'e cotroller (ill !oitor t"ese )al%es& a#

es%re t"ese li!its are ot e8cee#e#.

TrippingD W"e a co#itio occ%rs t"at t"e )olta'e cotroller

caot cotrol& o$te ti!es t"e )olta'e cotroller (ill trip. A trip

!eas t"e )olta'e cotroller -*, (a, o$ t"e cotactor (ill s"%t o$$ t"e

i#i)i#%al precipitator po(er circ%it. A s"ort isi#e t"e electrostatic

precipitator $iel# ca%se# *, a $alle #isc"ar'e electro#e -(ire& or a

s"orte# o%t Silicoe Cotrolle# Recti$ier are e8a!ples o$ co#itios

t"at a )olta'e cotroller caot cotrol. -PIC O7 CLOSE3UP O7

TRIP LIGHT ON 2=C 7ACE PANEL

%peration

To !a8i!i+e electrostatic precipitator e$$iciec, a )olta'e cotroller

%s%all, atte!pts to icrease t"e electrical po(er #eli)ere# to t"e $iel#.

Ho(e)er i so!e co#itios a )olta'e cotroller !%st >%st !aitaipo(er at a costat le)el. Icrease# electrical po(er ito t"e

electrostatic precipitator #irectl, correlates (it" *etter precipitator

per$or!ace& *%t t"ere is a li!it. I$ too !%c" )olta'es is applie# $or a

'i)e co#itio -as !etioe# i t"e spar5 reactio sectio& a spar5


15/32

o)er (ill occ%r. %ri' a spar5 o)er precipitator per$or!ace i t"at

$iel# (ill #rop to +ero& re#eri' t"at $iel# te!poraril, ie$$ecti)e.

To o)erco!e t"e crippli' e$$ect t"at spar5 o)er "as to icreasi' t"e

electrical po(er i t"e precipitator $iel#& spar5 respose al'orit"!s

"a)e *ee #e)elope# t"at (ill iterr%pt po(er %po #etectio o$ aspar5& t"e ra!p po(er *ac5 %p to a "i'" le)el. T"ese respose

al'orit"!s ca 'reatl, i$l%ece o)erall precipitator per$or!ace.

1. Tras$or!er3Recti$iers

T"e tras$or!er3recti$ier rati' s"o%l# *e !atc"e# to t"e loa#

i!pose# *, t"e electrical $iel# or *%s sectio. T"e po(er s%ppl, (ill

per$or! *est ("e t"e tras$or!er3recti$iers operate at F@ 3 ;@< o$

t"e rate# capacit,& (it"o%t e8cessi)e spar5i'. T"is re#%ces t"e!a8i!%! coti%o%s3loa# )olta'e a# coroa po(er ip%ts. Practical

operati' )olta'es $or tras$or!er3recti$iers #epe# o9

o Collecti' plate spaci'

o Gas a# #%st co#itios

o Collecti' plate a# #isc"ar'e electro#e 'eo!etr,

At seco#ar, c%rret le)els o)er 1@@ !A& iteral i!pe#ace o$ a

tras$or!er3recti$ier is lo(& ("ic" !a5es sta*le a%to!atic )olta'e

cotrol !ore #i$$ic%lt to ac"ie)e. T"e #esi' o$ t"e tras$or!er3

recti$ier s"o%l# call $or t"e "i'"est possi*le i!pe#ace t"at is

co!!es%rate (it" t"e applicatio a# per$or!ace re4%ire!ets.

O$te& t"is li!its t"e si+e o$ t"e electrical $iel# or *%s sectio.

It is 'eeral practice to a## a##itioal i!pe#ace i t"e $or! o$ a

c%rret3li!iti' reactor i t"e pri!ar, circ%it. T"is reactor (ill li!it

t"e pri!ar, c%rret #%ri' arci' a# also i!pro)e t"e (a)e s"ape o$

t"e )olta'e:c%rret $e# ito t"e tras$or!er3recti$ier./. Coroa c%rret #esit,

Coroa c%rret #esit, s"o%l# *e i t"e ra'e o$ 1@ 3 1@@ !A:1@@@ $t/

o$ plate area. -Calc%late t"is %si' seco#ar, c%rret #i)i#e# *,

collecti' area o$ t"e electrical $iel# or *%s sectio. T"e act%al le)el

#epe#s %po9


16/32

o Locatio o$ electrical $iel# or *%s sectio to *e eer'i+e#

o Collecti' plate area

o Gas a# #%st co#itios

o Collecti' electro#e a# #isc"ar'e (ire 'eo!etr,

!bout as Distribution #ystems -Bac5 to top

Oe electrical $iel# or *%s sectio o$ a electrostatic precipitator is *,

itsel$ a i#epe#et precipitator. Its operatio is 'o)ere# *, t"e ilet

'as a# #%st co#itios& as (ell as t"e collecti' plate a# #isc"ar'e

electro#e 'eo!etries.

Wit"i t"is electrical $iel# or *%s sectio& oe 'as passa'e is also a

i#epe#et precipitator 3 'o)ere# *, t"e sa!e $actors. -Note t"at t"e'as passa'e s"ares t"e )olta'e le)el (it" t"e a#>acet 'as passa'es o$

t"e sa!e electrical $iel# or *%s sectio& *%t ot t"e coroa c%rret

le)el& ("ic" ca *e #i$$eret i eac" 'as passa'e.

T"is poits to t"e i!portace o$ creati' si!ilar 'as a# #%st

co#itios 1 at t"e ilet o$ eac" electrical $iel# or *%s sectio& a# /

$%rt"er at t"e ilet o$ eac" 'as passa'e o$ t"e electrical $iel# or *%s

sectio. I#eall,& %i$or!it, is #esire# i9

Gas )elocit,

Gas te!perat%re

%st loa#i'

Gas )elocit, #istri*%tio ca *e !ost e$$ecti)el, i$l%ece# *, t"e %se

o$ 'as #istri*%tio #e)ices.

T"e 4%alit, o$ 'as )elocit, #istri*%tio ca *e !eas%re# i a scale#3

#o( !o#el o$ t"e precipitator a# its #%ct(or5& a# also i t"e

precipitator itsel$. T,pical criteria are *ase# o ICAC -Istit%te o$Clea Air Co!paies reco!!e#atios %si' a)era'e 'as )elocities

or o a calc%late# R2S statistical represetatio o$ t"e 'as )elocit,

patter.


17/32

I 'eeral& 'as #istri*%tio #e)ices cosist o$ t%ri' )aes i t"e ilet

#%ct(or5& a# per$orate# 'as #istri*%tio plates i t"e ilet a#:or

o%tlet $iel#s o$ t"e precipitator.

!bout Rapping #ystems -Bac5 to top

Rappers are ti!e3cotrolle# s,ste!s pro)i#e# $or re!o)i' #%st $ro!t"e collecti' plates a# t"e #isc"ar'e electro#es as (ell as $or 'as

#istri*%tio #e)ices -optioal a# $or "opper (alls -optioal.

Rappi' s,ste!s !a, *e act%ate# *, electrical or pe%!atic po(er& or

*, !ec"aical !eas. T%!*li' "a!!ers !a, also *e %se# to

#islo#'e as". Rappi' !et"o#s icl%#e9

Electric )i*rators

Electric soleoi# pisto #rop rappers Pe%!atic )i*rati' rappers

T%!*li' "a!!ers

Soic "ors -#o ot re4%ire tras!issio asse!*lies

1. isc"ar'e Electro#e Rappi'

I 'eeral& #isc"ar'e electro#es s"o%l# *e 5ept as $ree as possi*le o$

acc%!%late# partic%late. T"e rappi' s,ste! $or t"e #isc"ar'e

electro#es s"o%l# *e operate# o a coti%o%s sc"e#%le (it" repeat

ti!es i t"e / 3 !i%te ra'e& #epe#i' o t"e si+e a# ilet

partic%late loa#i' o$ t"e precipitator.

/. Collecti' Plate Rappi'

Collecti' plate rappi' !%st re!o)e t"e *%l5 o$ t"e precipitate# #%st.

T"e collecti' plates are s%pporte# $ro! a)il *ea!s or #irectl, (it"

"oo5s $ro! t"e precipitator casi'. Wit" a)il *ea! s%pport& t"e

i!pact o$ t"e rappi' s,ste! is #irecte# ito t"e *ea!s locate# at t"e

lea#i' a#:or traili' e#'e o$ t"e collecti' plates. 7or #irect casi's%pport& t"e i!pact is #irecte# ito t"e rapper *ea!s locate# at or ear

t"e ceter o$ t"e top o$ t"e collecti' plates.

T"e $irst electrical $iel# 'eerall, collects a*o%t @3@< o$ t"e ilet

#%st loa#. T"e $irst $iel# plates s"o%l# *e rappe# o$te eo%'" so t"at

t"eir precipitate# la,er o$ partic%late is a*o%t 0: 3 1:/ t"ic5. T"ere is


18/32

o a#)ata'e i rappi' !ore o$te sice t"e precipitate# #%st "as ot

,et a''lo!erate# to a s"eet ("ic" re4%ires a !ii!%! la,er

t"ic5ess. S"eet $or!atio is essetial to !a5e t"e #%st #rop ito t"e

precipitator "opper (it"o%t re3etrai!et ito t"e 'as strea!.

Rappi' less $re4%etl, t,picall, res%lts i a #eterioratio o$ t"eelectrical po(er ip%t *, a##i' a a##itioal resistace ito t"e

po(er circ%it. Oce a opti!%! rappi' c,cle "as *ee $o%# $or t"e

$irst electrical $iel# -("ic" !a, )ar, across t"e $ace o$ a lar'e

precipitator& t"e opti!%! rappi' c,cles $or t"e #o(strea!

electrical $iel#s ca *e esta*lis"e#.

T"e collecti' plate rappi' s,ste! o$ t"e $irst $iel# "as a repeat ti!e

T e4%al to t"e ti!e it ta5es to *%il# a 0: 3 1:/la,er o t"e collecti'plates. T"e plates i t"e seco# $iel# s"o%l# "a)e a repeat ti!e o$

a*o%t T& a# t"e plates i t"e t"ir# $iel# s"o%l# "a)e a repeat ti!e o$

/T. I#eall,& t"ese repeat ti!es ,iel# a #eposite# la,er o$ 0:31:/ $or

t"e plates i all t"ree $iel#s. A#>%st!et !a, *e re4%ire# $or $actors

s%c" as #%st resisti)it,& #%st la,er co"esi)eess& 'as te!perat%re

e$$ects& electrical $iel# "ei'"t a# le't"& a# t"e collecti' area

ser)e# *, oe rapper.

0. Gas istri*%tio Plate a# Hopper Wall Rappi'

T"e 'as #istri*%tio plates s"o%l# also *e 5ept $ree o$ e8cessi)e

partic%late *%il#%p a# !a, re4%ire rappi' o a coti%o%s *ase (it"

a c,cle ti!e i t"e 1@3/@ !i%te ra'e& #epe#i' o t"e ilet

partic%late loa#i' o$ t"e precipitator a# t"e at%re o$ t"e partic%late.

Gas #istri*%tio plates i t"e o%tlet o$ t"e precipitator !a, *e rappe#

less o$te -e)er, 0@ 3 @ !i%tes.

. I!pro)i' Rappi' S,ste! Per$or!aceAll precipitator rappi' s,ste!s allo( a#>%st!et o$ rappi'

$re4%ec,& or!all, starti' (it" t"e "i'"est $re4%ec, -t"e least ti!e

*et(ee raps& pro'ressi' to t"e lo(est $re4%ec,. T"e ti!es t"at are

act%all, a)aila*le !a, *e li!ite#. Rappi' s,ste!s (it" pe%!atic or

electric act%ators allo( )ariatios o$ t"e rappi' itesit,. Pe%!atic


19/32

or electric )i*rators allo( a#>%st!ets o$ t"e rappi' ti!e. State3o$3

t"e3art rapper cotrols allo( selectio o$ rappi' se4%eces& selectio

o$ i#i)i#%al rappers& a# pro)i#e ati3coici#ece sc"e!es ("ic"

allo( ol, oe rapper to operate at a 'i)e ti!e.

Rappi' s,ste!s ca *e opti!i+e# $or top precipitator per$or!ace

%si' precipitator po(er ip%t a# stac5 opacit, as criteria.

Opti!i+atio o$ t"e rappi' s,ste! starts (it" t"e #isc"ar'e electro#e

rappi' s,ste! operati' o its o( ti!e sc"e#%le& $or e8a!ple (it"

repeat ti!es o$ / 3 !i%tes. T"e rappi' s,ste! $or t"e 'as

#istri*%tio screes i t"e ilet a# o%tlet o$ t"e precipitator s"o%l#

t"e *e operate# (it" repeat ti!es o$ /30 !i%tes $or t"e ilet a# / 30 "o%rs $or t"e o%tlet screes.

T"e ol, rappi' s,ste! re4%iri' opti!i+atio is t"e collecti' plate

rappi' s,ste!. T"e opti!i+atio s"o%l# start (it" t"e Collecti'

Plate Rappi' Sc"e#%le #eter!ie# a*o)e. Ne8t& t"e rappi'

$re4%ec, o$ t"e ilet $iel# s"o%l# *e icrease# or #ecrease# %til t"e

electrical po(er ip%t o$ t"e ilet $iel# re!ais costat. Ne8t& t"e

rappi' $re4%ec, o$ t"e ot"er $iel#s s"o%l# *e a#>%ste# i se4%ece

%til t"eir electrical po(er ip%ts re!ai costat. I$ t"e stac5 opacit,

trace s"o(s rappi' spi5es& t"e rappi' itesit, s"o%l# *e re#%ce#

("ile o*ser)i' t"e electrical po(er ip%t o$ t"e precipitator.

T"e a#>%st!et o$ t"e rappi' s,ste! $or opti!%! precipitator

per$or!ace is a slo( process. It re4%ires a s%*statial a!o%t o$ ti!e

$or sta*ili+atio a$ter eac" a#>%st!et.

!bout 'oppers -Bac5 to top

Precipitator "oppers are #esi'e# to co!pletel, #isc"ar'e #%st loa# o#e!a#. T,picall,& precipitator "oppers are recta'%lar i cross3

sectio (it" si#es o$ at least @3#e'ree slope. T"ese "oppers are

is%late# $ro! t"e ec5 a*o)e t"e #isc"ar'e $la'e (it" t"e is%latio

co)eri' t"e etire "opper area. I a##itio& t"e lo(er 1:3 1:0 o$ t"e


20/32

"opper (all !a, *e "eate#. isc"ar'e #ia!eters are 'eerall, 3

1/.

1. Is%latio

Is%latio pro)i#es protectio $or $acilit, persoel as (ell as (or5i'

to retai as !%c" "opper (all te!perat%re as possi*le. Hopper (allte!perat%re retetio #isco%ra'es co#esatio o t"e isi#e o$ t"e

"opper. Heaters are a##e# to es%re "ot !etal s%r$aces i!!e#iatel,

a*o)e t"e $l, as" #isc"ar'e.

/. 7acilitati' "opper #isc"ar'e

Hopper #isc"ar'e pro*le!s are ca%se# *, co!pactio o$ t"e $l, as" i

t"e "opper. Co!pactio c"aracteristics are a$$ecte# *, !oist%re

cotet& particle si+e a# s"ape& "ea# o$ !aterial& a# )i*ratio. T"e$lo( o$ $l, as" o%t o$ t"e "opper ca *e $acilitate# *, t"e %se o$

e8teral )i*rators. T"ese ca operate o t"e o%tsi#e (all o$ t"e "opper

or o a iteral "opper *a$$le.

0. Hopper $l%i#i+ers

Hopper $l%i#i+ers "a)e a !e!*rae t"at per!its air $lo( to t"e $l, as"

#irectl, a*o)e. T"is air $lo( $ills t"e )oi#s *et(ee t"e $l, as"

particles at a sli'"t press%re& c"a'es t"e repose a'le o$ t"e particles&

a# pro!otes 'ra)it, $lo(.

. As" "a#li' s,ste!

T"e $l, as" "a#li' s,ste! e)ac%ates t"e $l, as" $ro! t"e "oppers&

a# trasports t"e $l, as" to reprocessi' or to #isposal. T"e as"

"a#li' s,ste! s"o%l# *e #esi'e# a# operate# to re!o)e t"e

collecte# $l, as" $ro! t"e "oppers (it"o%t ca%si' re3etrai!et ito

t"e 'as $lo( t"ro%'" t"e precipitator. T"e #esi' o$ t"e as" "a#li'

s,ste! s"o%l# allo( $or $le8i*ilit, o$ sc"e#%li' t"e "opper#isc"ar'es accor#i' to t"e $l, as" *ei' collecte# i t"ese "oppers.

Eit"er t"e precipitator "opper or t"e $ee#er "opper is %se# $or

te!poraril, stori' !aterial prior to #isc"ar'e. T"ree t,pes o$

"a#li' s,ste!s are i %se9


21/32

Ne'ati)e press%re or )ac%%! s,ste!

Coects to t"e "opper *, a si!ple #isc"ar'e )al)e

Positi)e press%re #il%te p"ase s,ste!

Uses a airloc53t,pe $ee#er t"e $ee#er is separate# $ro! t"e "opper *,

a ilet 'ate a# $ro! t"e co)e,i' lie *, a #isc"ar'e 'ate Positi)e press%re #ese p"ase s,ste!

Coects to t"e "opper (it" a airloc5 t,pe $ee#er.

!bout Ductwor( -Bac5 to top

%ct(or5 coects t"e precipitator (it" %pstrea! a# #o(strea!

e4%ip!et. T"e #esi' o$ t"e #%ct(or5 ta5es ito cosi#eratio t"e$ollo(i'9

Lo( resistace to 'as $lo(

Ac"ie)e# *, selecti' a s%ita*le cross3sectio $or t"e #%ct(or5 a# *,

istalli' 'as $lo( cotrol #e)ices& s%c" as t%ri' )al)es a# $lo(

strai'"teers

Gas )elocit, #istri*%tio

Gas $lo( cotrol #e)ices are %se# to !aitai 'oo# 'as )elocit,

#istri*%tio

2ii!al $allo%t o$ $l, as"

7allo%t ca *e !ii!i+e# *, %si' a s%ita*le trasport )elocit,

2ii!al strati$icatio o$ t"e $l, as"

A s%ita*le trasport )elocit, also re#%ces $l, as" strati$icatio i t"e

'as strea!

Lo( "eat loss

T"e 'oal is to re#%ce t"e "eat loss o$ t"e $l%e 'as to a le)el t"at (illpre)et aci# or !oist%re co#esatio i t"e #o(strea! e4%ip!et&

re4%iri' t"e %se o$ t"er!al is%latio protecte# *, e8teral si#i'.

Str%ct%ral ite'rit,

%ct(or5 str%ct%re s%pports its total loa#& icl%#i' (i# a# so(

loa#s. T"e #esi' also allo(s $or acc%!%late# $l, as"&


22/32

e'ati)e:positi)e operati' press%re& a# 'as te!perat%re. E8pasio

>oits are %se# to acco!!o#ate t"er!al 'ro(t".

!bout as elocity Distribution -Bac5 to topE$$iciet precipitator per$or!ace #epe#s "ea)il, %po "a)i'

si!ilar 'as co#itios at t"e ilet o$ eac" electrical $iel# or *%s sectio

a# at t"e ilet o$ eac" 'as passa'e o$ t"e electrical $iel# or *%s

sectio. Ui$or!it, o$ 'as )elocit, is also #esira*le 3 'oo# 'as

)elocit, #istri*%tio t"ro%'" a precipitator !eets t"ese re4%ire!ets9

< o$ all !eas%re# 'as )elocities J 1.1 ti!es t"e a)era'e 'as

)elocit, ;;< o$ all !eas%re# 'as )elocities J 1.@ ti!es t"e a)era'e 'as

)elocit,

1. I!pro)i' Gas =elocit, istri*%tio

T"e 'as )elocit, #istri*%tio i a precipitator ca *e c%sto!i+e#

accor#i' to t"e #esi' o$ t"e precipitator a# t"e c"aracteristics o$

t"e #%st particles. Tra#itioall,& precipitators "a)e *ee #esi'e# (it"

%i$or! 'as )elocit, #istri*%tio t"ro%'" t"e electrical $iel#s& to a)oi#

"i'"3)elocit, areas t"at (o%l# ca%se re3etrai!et. W"ile t"is is still

a reco!!e#e# practice& t"ere is a a#)ata'e i so!e cases to

#e)elopi' a )elocit, pro$ile t"at *ri's !ore particles closer to t"e

"opper.

Bot" o$ t"ese sc"e!es "a)e applicatios i site3speci$ic co#itios.

Gas )elocit, #istri*%tio ca *e cotrolle# *, t"e $ollo(i'9

A##i':i!pro)i' 'as $lo( cotrol #e)ices i t"e ilet #%ct(or5

A##i':i!pro)i' $lo( cotrol #e)ices i t"e ilet o$ t"eprecipitator

A##i':i!pro)i' $lo( cotrol #e)ices i t"e o%tlet o$ t"e

precipitator

A##i' a rappi' s,ste! to t"e $lo( cotrol #e)ices -("ere

applica*le


23/32

A##i':i!pro)i' ati3sea5 *a$$les at t"e perip"eries o$ t"e

electrical $iel#s

A##i':i!pro)i' "opper *a$$les

Eli!iati' air lea5a'es ito t"e precipitator

!bout Re)entrainment -Bac5 to top

Re#%ci' rappi' re3etrai!et to a accepta*le le)el 'eerall,

re4%ires a s%*statial i!pro)e!et o$ t"e 'as )elocit, #istri*%tio a#

t"e electrical po(er #esit, a# %i$or!it,& as (ell as a e8te#e#

opti!i+atio pro'ra! $or t"e collecti'3plate rappi' s,ste!.

7actors A$$ecti' Re3etrai!etRe3etrai!et o$ collecte# particles is t"e !a>or cotri*%tor to

partic%late e!issios o$ t"e precipitator. I so!e cases& re3etrai!et

acco%ts $or @ 3 @< o$ t"e resi#%al. T"e !a>or ca%ses o$ re3

etrai!et are as $ollo(s9

Particles9 Lo( co"esi)eess

Lo( a#"esio to collecti' plates

Particle si+e

Lo( resisti)it,

=olta'e

Cotrols9Spar5 rate setti'

esi'9 Collecti' plate #esi'

isc"ar'e electro#e #esi'

Plate spaci'

Rappi'

S,ste!9

7re4%ec,

Itesit,%ratio -i$ applica*le

Electrical

7iel#9

Collecti' plate a# #isc"ar'e electro#e rappi'

Spar5i'

Saltatio

Erosio -locali+e# "i'" 'as )elocit,


24/32

Sea5a'e

Hopper9 Hopper #esi'

Lea5a'e -"opper )al)e

Hopper 'as $lo(

!bout "orona Power -Bac5 to top

Precipitator coroa po(er is t"e %se$%l electrical po(er applie# to t"e

$l%e 'as strea! to precipitate particles. Eit"er precipitator collecti'

e$$iciec, or o%tlet resi#%al ca *e e8presse# as a $%ctio o$ coroa

po(er i Watts:1@@@ ac$! o$ $l%e 'as& or i Watts:1@@@ $t o$

collectio area.

T"e separatio o$ particles $ro! t"e 'as $lo( i a electrostaticprecipitator #epe#s o t"e applie# coroa po(er. Coroa po(er is t"e

pro#%ct o$ coroa c%rret a# )olta'e. C%rret is ee#e# to c"ar'e t"e

particles. =olta'e is ee#e# to s%pport a electrical $iel#& ("ic" i t%r

trasports t"e particles to t"e collecti' plates.

I t"e lo(er ra'e o$ collecti' e$$iciecies& relati)el, s!all icreases

i coroa po(er res%lt i s%*statial icreases i collecti' e$$iciec,.

O t"e ot"er "a#& i t"e %pper ra'es& e)e lar'e icreases i coroa

po(er (ill res%lt i ol, s!all e$$iciec, icreases.

E4%all,& i t"e lo(er ra'e o$ t"e coroa po(er le)els& a s!all

icrease i t"e coroa po(er res%lts i a s%*statial re#%ctio i t"e

'as strea! particle cotet. I t"e %pper ra'e o$ t"e coroa po(er

le)el& a lar'e icrease is re4%ire# to re#%ce t"e particle cotet.

Opti!i+i' Coroa Po(er

Opti!%! co#itios #epe# %po t"e locatio o$ t"e $iel# -ilet&

ceter a# o%tlet& $l, as" c"aracteristics -resisti)it, a# p",sicalco#itios -collecti' plates a# #isc"ar'e (ires. Coroa po(er

le)els ca *e opti!i+e# *, a#>%sti' or opti!i+i' t"e $ollo(i'9

Gas )elocit,9 Ui$or!it,

7l, As"9Particle si+e Resisti)it,


25/32

=olta'e

Cotrols9

Spar5 rate setti'

C%rret )olta'e li!its

esi'9 Plate spaci'

Collecti' plate #isc"ar'e electro#e #esi'

Rappi'S,ste!9

7re4%ec, itesit,

S%pport

Is%lator9P%r'e air s,ste! operatio

!bout Performance Improvements -Bac5 to top

I!pro)e!et or opti!i+atio o$ precipitator operatio ca res%lt i

si'i$icat sa)i's. 2a, speci$ic sit%atios eco%ra'e a re)ie( o$precipitator operatio9

eterioratio o$ e8isti' e4%ip!et

Ti'"tei' o$ air poll%tio e!issio re'%latios

C"a'es i pro#%cts a#:or pro#%ctio rates

7re4%et $orce# o%ta'es

e3rati' o$ pro#%ctio

To lear !ore a*o%t per$or!ace i!pro)e!et pro'ra!s& re$er to t"e

appropriate sectio9

Gas =elocit, istri*%tio

Coroa Po(er

Re3etrai!et

Process I!pro)e!ets

7l%e Gas:7l, As" Co#itioi'

E4%ip!et I!pro)e!ets

Equipment Improvements -Bac5 to top

T"e o*>ecti)es o$ e4%ip!et i!pro)e!ets are to opti!i+e coroa

po(er& re#%ce re3etrai!et& a# opti!i+e 'as )elocit, #istri*%tio

isi#e t"e precipitator. So!e i!portat topics to cosi#er ("e

plai' e4%ip!et i!pro)e!ets icl%#e9
http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#tophttp://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#gds3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#cp4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#r4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#cpi4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#fgfac4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#ei4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#tophttp://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#tophttp://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#gds3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#cp4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#r4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#cpi4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#fgfac4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#ei4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#top


26/32

1. Precipitator Si+e

W"e si+i' t"e precipitator& it is i!portat to pro)i#e a cross3sectio

t"at (ill !aitai a accepta*le 'as )elocit,. It is also i!portat to

pro)i#e $or eo%'" total #isc"ar'e (ire le't" a# collecti' plate

area& so t"at t"e #esire# speci$ic coroa c%rret a# electrical $iel# ca*e applie#.

/. Gas =elocit, istri*%tio

I!pro)i' 'as )elocit, #istri*%tio i t"e precipitator re#%ces particle

re3etrai!et a# *oosts precipitator e$$iciec,. T,picall,& a %i$or!

'as )elocit, is #esire#& *%t t"ere are site3speci$ic e8ceptios. Gas

)elocit, #istri*%tio ca *e !o#i$ie# *, %si' $lo( cotrol #e)ices

a# *a$$les. Re$er to t"e special sectio o 'as )elocit, #istri*%tio.0. Coroa Po(er

T"e separatio o$ #%st particles $ro! t"e 'as $lo( i a electrostatic

precipitator #epe#s o t"e applie# coroa po(er. Coroa po(er is t"e

pro#%ct o$ coroa c%rret a# )olta'e. C%rret is ee#e# to c"ar'e t"e

particles. =olta'e is ee#e# to s%pport a electrical $iel#& ("ic" i t%r

trasports t"e particles to t"e collecti' plates. 7or a##itioal

i$or!atio& re$er to Coroa Po(er.

. Sectioali+atio

T"e precipitator is #i)i#e# ito electrical sectios t"at are cross3(ise

a# parallel to t"e 'as $lo( to acco!!o#ate spatial #i$$ereces i 'as

a# #%st co#itios. Opti!i+atio o$ coroa po(er i)ol)es a#>%sti'

t"e coroa po(er -seco#ar, )olta'e a# c%rret i eac" electrical

sectio $or opti!%! co#itios.

. Particle Re3etrai!et

2ii!i+i' re3etrai!et o$ #%st particles is i!portat toi!pro)e!et o$ precipitator e$$iciec,. 2ost precipitator e4%ip!et

a$$ects t"e re3etrai!et le)el. 7or a #etaile# #isc%ssio& )isit t"e

special sectio o re3etrai!et.

. A##itioal E4%ip!et

Per$or!ace i!pro)e!et optios icl%#e t"e istallatio o$ a seco#


27/32

precipitator i series (it" t"e e8isti' precipitator %si' $a*ric $ilters

#o(strea! o$ t"e precipitator a# a##i' a seco# particle collector

i parallel (it" t"e e8isti' collector. Ot"er possi*ilities icl%#e soic

or electrostatic particle a''lo!erators %pstrea! o$ t"e precipitator a

!ec"aical %pstrea! collector or a electrostaticall,3e"ace# or!ec"aical collector& or a $ilter #o(strea! o$ t"e precipitator.

F. Re)ie( t"e Geeral E4%ip!et Re4%ire!ets

Re)ie(i' t"e Ne%#or$er Ko(le#'e Base sectios o e4%ip!et

(ill pro)i#e a##itioal isi'"t ito per$or!ace i!pro)e!ets.

7or !ore i$or!atio& see t"ese relate# topics9

Gas =elocit, istri*%tioCoroa Po(er

Re3etrai!et

isc"ar'e Electro#es

Collecti' Plates

Po(er S%pplies

Gas istri*%tio

Rappi' S,ste!s

Hoppers a# %st Ha#li'

%ct(or5

"ombustion Process Improvements for Power Plants -Bac5 to

top

Co!*%stio process co#itios !ail, a$$ect t"e coroa po(er le)el.

T"e pri!ar, cotri*%tors to co!*%stio process co#itios a# t"eir

e$$ects icl%#e9Coal

7l%e 'as $lo( rate

7l%e 'as !oist%re cotet

7l, as" resisti)it,
http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#gds3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#cp4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#r4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#de3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#cp3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#psac3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#gds3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#rs3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#hadh3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#d3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#tophttp://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#tophttp://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#gds3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#cp4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#r4http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#de3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#cp3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#psac3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#gds3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#rs3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#hadh3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#d3http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#tophttp://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#top


28/32

7l, as" ilet loa#i'

7l, as" particle si+e

Coal !ills

7l, as" particle si+e

U*%re# car*o -LOI7%race

Base loa#:s(i' loa# operatio

7l%e 'as $lo( rate

B%rers

7l%e 'as te!perat%re

7l, as" resisti)it,

U*%re# car*o -LOIAir pre3"eaters

Rotatio

Gas $lo( patter

Gas te!perat%re patter

SO0 #istri*%tio patter

"oal

Bit%!io%s coals $ro! Easter !ies& s%*3*it%!io%s a# li'ite

coals $ro! Wester !ies& a# li'ites $ro! Te8as !ies are

s%*statiall, #i$$eret $ro! eac" ot"er i t"e co!*%stio process. Coal

*le#i' is o( %se# $or operatioal a# $iacial *ee$its. T"is

res%lts i a (i#e ra'e o$ *oiler a# precipitator operati' co#itios.

Precipitati' $l, as" $ro! #i$$ic%lt coals ca *e i!pro)e# (it"

co#itioi' s,ste!s. Ho(e)er& t"e $%race a# its associate#e4%ip!et ca still ca%se pro*le!s i t"e precipitator& partic%larl,

coal !ills& *%rers& a# air pre3"eaters.

"oal *ills


29/32

T"e setti' o$ t"e coal !ills a# classi$iers #e$ies t"e coal particle

si+e ("ic" i t%r i!pacts t"e $l, as" particle si+e. Lar'er coal

particles are !ore #i$$ic%lt to co!*%st& *%t lar'er $l, as" particles are

easier to collect i t"e precipitator.

+urnace

Base3loa# operatio o$ t"e *oiler is %s%all, *etter $or precipitator

operatio t"a s(i'3loa# operatio #%e to !ore sta*le operati'

co#itios. Boiler operatio at lo( loa#s !a, *e as pro*le!atic $or

t"e precipitator as operati' t"e *oiler at its !a8i!%! loa# le)el& #%eto $allo%t o$ $l, as" i t"e #%ct(or5& lo( 'as te!perat%res& a#

#eterioratio o$ t"e 4%alit, o$ t"e 'as )elocit, #istri*%tio.

I$ lo( loa# operatio caot *e a)oi#e#& t"e istallatio o$ a##itioal

'as $lo( cotrol #e)ices i t"e ilet a# o%tlet o$ t"e precipitator !a,

pro)e *ee$icial.

"oal Burner

T"e operatio o$ coal *%rers& to'et"er (it" t"e setti' o$ t"e coal

!ills a# t"eir classi$iers& a$$ects t"e perceta'e o$ %*%re# car*o

-LOI or UBC i t"e $l, as". T"e %se o$ Lo3NO8 *%rers icreases t"is

perceta'e& a# ca%ses re3etrai!et a# icrease# spar5i' i t"e

precipitator. 7%rt"er& t"e UBC te#s to a*sor* SO0& ("ic" i t%r

icreases t"e $l, as" resisti)it,. O)er3$ire air opti!i+atio or coal3

re*%r s,ste!s !a, re#%ce UBC i t"e $l, as".

!ir Pre)heater

Re'eerati)e air pre3"eaters ca%se te!perat%re a# SO0strati$icatio

i t"e #o(strea! 'as $lo(. T"is pro*le! is !ore se)ere i closel,


30/32

co%ple# s,ste!s& ("ere t"e precipitator is locate# close to t"e air pre3

"eater. epe#i' %po site3speci$ic co#itios& $lo( !i8i' #e)ices

!a, *e istalle# i t"e #%ct(or5 to t"e precipitator& or $l%e 'as

co#itioi' s,ste!s !a, *e %se# to e4%ali+e t"e 'as $lo(

c"aracteristics.

+ly !sh and +lue as "onditioning -Bac5 to top

7l%e 'as a# $l, as" c"aracteristics at t"e ilet #e$ie precipitator

operatio. T"e co!*iatio o$ $l%e 'as aal,sis& $l%e 'as te!perat%re

a# $l, as" c"e!istr, pro)i#es t"e *ase $or $l, as" resisti)it,.

T,picall,& $l, as" resisti)it, i)ol)es *ot" s%r$ace a# )ol%!eresisti)it,. As 'as te!perat%re icreases& s%r$ace co#%cti)it,

#ecreases a# )ol%!e resisti)it, icreases.

I lo(er 'as te!perat%re ra'es& s%r$ace co#%cti)it, pre#o!iates.

T"e c%rret passi' t"ro%'" t"e precipitate# $l, as" la,er is co#%cte#

i a $il! o$ (ea5 s%l$%ric aci# o t"e s%r$ace o$ t"e particles.

7or!atio o$ t"e aci# $il! -$ro! SO0a# H/O is i$l%ece# *, t"e

s%r$ace c"e!istr, o$ t"e $l, as" particles.

I "i'"er 'as te!perat%re ra'es& )ol%!e co#%cti)it, pre#o!iates.

C%rret co#%ctio t"ro%'" t"e *o#ies -)ol%!e o$ t"e precipitate# $l,

as" particles is 'o)ere# *, t"e total c"e!istr, o$ t"e particles.

7l, as" resisti)it, ca *e !o#i$ie# -'eerall, (it" t"e itet to re#%ce

it *, i>ecti' oe or !ore o$ t"e $ollo(i' %pstrea! o$ t"e

precipitator9

S%l$%r trio8i#e -SO0

A!!oia -NH0 Water

#ulfur $rio,ide and !mmonia "onditioning #ystems


31/32

I !ost cases& a s%l$%r trio8i#e co#itioi' s,ste! is s%$$iciet to

re#%ce $l, as" resisti)it, to a accepta*le le)el. T"e so%rce o$ s%l$%r

trio8i#e ca *e li4%i# s%l$%r #io8i#e& !olte ele!etal s%l$%r& or

'ra%late# s%l$%r. It is also possi*le to co)ert ati)e $l%e 'as SO/to

SO0.I so!e istaces& a!!oia aloe "as *ee pro)e a s%ita*le

co#itioi' a'et. It $or!s a a!!oia3*ase# partic%late to icrease

t"e space c"ar'e. T"e so%rce o$ a!!oia !a, *e li4%i# a",#ro%s or

a4%eo%s a!!oia& or soli# %rea.

7iall,& s%l$%r trio8i#e a# a!!oia !a, *e %se# i co!*iatio.

T"is sol%tio "as *ee s%ccess$%l *eca%se it ca lo(er $l, as"

resisti)it, a# also $or! a!!oia *is%l$ate. T"e latter icreases t"ea#"esio o$ particles& a# t"%s re#%ces re3etrai!et losses.

-ater In.ection

T"e i>ectio o$ (ater %pstrea! o$ t"e precipitator lo(ers t"e 'as

te!perat%re a# a##s !oist%re to t"e $l%e 'as. Bot" are *ee$icial i

col#3si#e precipitator applicatios. Ho(e)er& care !%st *e ta5e t"at

all o$ t"e (ater is e)aporate# a# t"at t"e (alls i t"e #%ct(or5 or 'as

#istri*%tio #e)ices #o ot 'et (et.

G E N E R A L S A 7 E T M P R E C A U T I O N S

Ans:Accidents do not


32/32

2. &mmediately report to person in"charge any dangerous condition or practice

you have observed.

*. e!ore working on motors or other rotating machines make sure that it

cannot be set in motion without your permission by removing !uses +

installing danger board on controlling switch.

-. 3horoughly discharge all cables to earth be!ore starting the work.

/. >lace rubber mats in !ront o! switchboards.

. 6o not close any switch unless you are !amiliar with the circuit which it

controls and know the reasons !or it being open.

4. 6o not work on live circuits. ?ake sure that all sa!ety precautions have been

taken.

8. 6o not close or open switch hesitantly. " do it ,uickly and positively.

;. o ot t"ro( (ater o li)e electrical apparat%s i case o$ $ire. Use proper e8ti'%is"er.

ash handling plant & esp

Documents