assignment for asp

8/18/2019 Assignment for ASP

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ASSIGNMENT # 1

1. Types of Electrostatic Precipitators & Scrubbers

2. Applications of Electrostatic Precipitators & Scrubbers3. Dierence between Electrostatic Precipitators & Scrubbers

COURSE TITLE:

ADVANED SEPA!AT"#N P!#ESS

SUBMITTED TO:

ASS#"ATE. P!#$. D!. A%"! SA$EE'

SUBMITTED BY:

%(A%%AD A!"S A%A)(N

%.S.1*+,-

1ST SE%ESTE!

INSTITUTE OF CHEMICAL ENGINEERING & TECHNOLOGY, UNIVERSITY OF

THE PUNJAB, LAHORE

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Tab! " C"$%!$%:

1' E!(%)"%a%*( P)!(*+*%a%")

1.1. "ntro/uction ,3

1.2. 0asic Principle of #peration ,3

1.3. Types of Electrostatic Precipitators ,-

1.3.1. Dry Electrostatic Precipitator,*

1.3.2. et Electrostatic Precipitator,

1.-. Applications of Electrostatic Precipitators 1-

' S()-bb!)

2.1. "ntro/uction 1

2.2. Types of Scrubbers 1

2.2.1. Dry Scrubbers1

2.2.2. et Scrubbers14

2.3. Applications of Scrubber25

3' C".+a)*"$ b!%/!!$ E!(%)"%a%*( P)!(*+*%a%") a$0 S()-bb!)

3.1. Electrostatic Precipitator24

3.2. Scrubbers3,

3.3. Econo6ical Aspects 3,

' R!!)!$(!

31

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1' ELECTROSTATIC PRECIPITATORS:

1.1. Introduction:

An electrostatic precipitator (ESP) is a filtration device that removes fine particles, like dust and

smoke, from a flowing gas using the force of an induced electrostatic charge minimally impeding

the flow of gases through the unit. [!

An electrostatic precipitator is a large, industrial emission"control unit. #t is designed to trap andremove dust particles from the e$haust gas stream of an industrial process. Precipitators are

used in these industries%

• Power&Electric• 'ement• 'hemicals• etals• Paper

#n many industrial plants, particulate matter created in the industrial process is carried as dust in

the hot e$haust gases. hese dust"laden gases pass through an electrostatic precipitator thatcollects most of the dust. 'leaned gas then passes out of the precipitator and through a stack to

the atmosphere. Precipitators typically collect **.*+ or more of the dust from the gas stream.

Precipitators function y electrostatically charging the dust particles in the gas stream. he

charged particles are then attracted to and deposited on plates or other collection devices.

-hen enough dust has accumulated, the collectors are shaken to dislodge the dust, causing it

to fall with the force of gravity to hoppers elow. he dust is then removed y a conveyor

system for disposal or recycling.

epending upon dust characteristics and the gas volume to e treated, there are many different

si/es, types and designs of electrostatic precipitators. 0ery large power plants may actuallyhave multiple precipitators for each unit.

1.2. Basic Principle of Operation:

Electrostatic precipitation removes particles from the e$haust gas stream of an industrial

process. 1ften the process involves comustion, ut it can e any industrial process that would

otherwise emit particles to the atmosphere.

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https://en.wikipedia.org/wiki/Electrostatic_chargehttps://en.wikipedia.org/wiki/Electrostatic_chargehttps://en.wikipedia.org/wiki/Electrostatic_charge


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Si$ activities typically take place%

• #oni/ation " 'harging of particles

• igration " ransporting the charged particles to the collecting surfaces

•

'ollection " Precipitation of the charged particles onto the collecting surfaces• 'harge issipation " 2eutrali/ing the charged particles on the collecting surfaces

• Particle islodging " 3emoving the particles from the collecting surface to the hopper

• Particle 3emoval " 'onveying the particles from the hopper to a disposal point

he ma4or precipitator components that accomplish these activities are as follows%

• ischarge Electrodes

• Power o6ponents

• Precipitator 'ontrols

• 3apping Systems

• Purge Air Systems

• 5lue 6as 'onditioning

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Fig. 1: Diagram of the principle of electrostatic precipitation [3]

1.3. !pes of "lectrostatic Precipitators:

Electrostatic precipitators are enerally /i7i/e/ into two broa/ roups8 /ry ESPs an/

wet ESPs. T9e /istinction is base/ on w9at 6et9o/ is use/ to re6o7e particulate

fro6 t9e collection electro/es. "n bot9 cases8 particulate collection occurs in t9e

sa6e 6anner. "n a//ition to wet an/ /ry options8 t9ere are 7ariations of internal ESP

/esins a7ailable. T9e two 6ost co66on /esins are wire+plate an/ wire+pipe

collectors. Electrostatic precipitators are often /esine/ wit9 se7eral co6part6ents8

to facilitate cleanin an/ 6aintenance.

1'3'1' D)2 E!(%)"%a%*( P)!(*+*%a%"):

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Dry ESP:s re6o7e /ust fro6 t9e collection electro/es by 7ibratin t9e electro/es

t9rou9 t9e use of rappers. o66on types of rappers are ra7ity i6pact 9a66ers

an/ electric 7ibrators. $or a i7en ESP8 t9e rappin intensity an/ fre;uency 6ust be

a/ely to /era/e perfor6ance. ?-@

F*4' : D)2 T2+! E!(%)"%a%*( P)!(*+*%a%") 536

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.ry )ype ElectrostaticPrecipitators

5i$ed Electrode (oving Electrode

ry type Electrostatic precipitator can e a fi$ed"electrode type or a moving"electrode type,

depending on the method for removing the collected dust.

#n the fi#ed$electrode t!pe, a collecting plate rapping device is used to remove the dust

collected on the collecting plate when the dust has accumulated to a certain thickness.

herefore, a thin dust layer always remains on the collecting plate surface with the fi$ed"

electrode type. Also, when rapping, some of the dust entrains the gas flow and is carried away

(rapping re"entrainment).

#n mo%ing$electrode t!pe, the collecting plates are divided into short strip elements that are

4oined y chains, and the collecting plates are moved slowly. he dust collected on the collecting

plate elements is completely scraped off y rotating rushes provided in the hoppers.

he moving"electrode type has the following features.

• he surface of the collecting plates is clean and there is no ack corona. herefore, fine,

high"resistivity dust can e efficiently collected.

• he rushes in the hopper scrape off the collected dust, and there is no reduction of

performance due to rapping re"entrainment.

• 7ecause the e8uipment always has high collection efficiency, it can e made compact.

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Fig. 3: &omparison of fi#ed$electrode t!pe and mo%ing$electrode t!pe "lectrostatic

precipitator

1.3.2. 'et "lectrostatic Precipitators:

T9e basic co6ponents of a wet ESP are t9e sa6e as t9ose of a /ry ESP wit9 t9e

eception t9at a wet ESP re;uires a water spray syste6 rat9er t9an a syste6 of

rappers. 0ecause t9e /ust is re6o7e/ fro6 a wet ESP in t9e for6 of a slurry8

9oppers are typically replace/ wit9 a /rainae syste6. et ESPs 9a7e se7eral

a/7antaes o7er /ry ESPs. T9ey can a/sorb ases8 because so6e pollutants to

con/ense8 are easily interate/ wit9 scrubbers8 an/ eli6inate re+entrain6ent of capture/ particles. et ESPs are not li6ite/ by t9e resisti7ity of particles since t9e

9u6i/ity in a wet ESP lowers t9e resisti7ity of nor6ally 9i9 resisti7ity particles.

Pre7iously8 t9e use of wet ESPs was restricte/ to a few speciali=e/ applications. As

9i9er eBciencies 9a7e currently beco6e 6ore /esirable8 wet ESP applications

9a7e been increasin. et ESPs are li6ite/ to operatin at strea6 te6peratures

un/er approi6ately 1,C$. "n a wet ESP8 collecte/ particulate is was9e/ fro6 t9e

collection electro/es wit9 water or anot9er suitable li;ui/. So6e ESP applications

re;uire t9at li;ui/ is spraye/ continuously into t9e as strea6 in ot9er cases8 t9e

li;ui/ 6ay be spraye/ inter6ittently. Since t9e li;ui/ spray saturates t9e as strea6

in a wet ESP8 it also pro7i/es as coolin an/ con/itionin. T9e li;ui/ /roplets in t9e

as strea6 are collecte/ alon wit9 particles an/ pro7i/e anot9er 6eans of rinsin

t9e collection electro/es. So6e ESP /esins establis9 a t9in l6 of li;ui/ w9ic9

continuously rinses t9e collection electro/es. ?-@

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-et )ype ElectrostaticPrecipitators

.uct )ype ElectrostaticPrecipitators

)u,ular )ype ElectrostaticPrecipitators

1.3.2.1. Duct Type Electrostatic PrecipitatorsF

-et Electrostatic precipitator that use parallel plates for the collecting electrodes are used in wet

dust collection systems for large 8uantities of process gas. 9sing a special no//le for the

collecting plates makes it possile to form a uniform water film with a small 8uantity of water.

7y selecting effective materials in accordance with the properties of the process gas and dust,

the wet type electrostatic precipitator can e adapted to various applications.

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Fig. (: 'et t!pe electrostatic precipitator

1.3.2.2. u)ular !pe 'et "lectrostatic Precipitators

he tuular"type wet electrostatic precipitator uses cylindrical electrodes for the collecting

electrode. he tuular"type wet electrostatic precipitator has a pressure"resistant, airtight

structure that is used for dust collection from e$plosive gases, comustile gases, to$ic gases,

and gases saturated with moisture that arise in the gas industry, the steel industry, and the

chemical industry.

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Fig. *: u)ular t!pe electrostatic precipitator [3]

1'3'3' ;*)!ae/ for /eli7ery to t9e site.

"n a wet wire+plate ESP8 t9e was9 syste6 is locate/ abo7e t9e electro/es. ?-@

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F*4' 7: ;*)!


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F*4' 8: ;*)! P*+! E!(%)"%a%*( P)!(*+*%a%")

1'3'' R"%a)2 T2+! E!(%)"%a%*( P)!(*+*%a%"):

he rotary tue type electrostatic precipitator is used for collecting high"viscosity tar generated

from caron electrode aking furnaces, or from the manufacturing processes of coke, asphalt,

or refractory materials, or oil mists generated in the manufacturing processes of ruer, tires,

etc.

he dust collecting electrode of the rotary tue type electrostatic precipitator is comined with

the outside casing, and is slowly rotated as a rotary kiln. Scrapers installed on the internal

surfaces of the tue continuously scrape off the high"viscosity tar that collects on the collecting

electrode throughout the whole tue surface. herefore, this is suitale for aerosol collection

that are difficult to process with conventional dry type Electrostatic precipitator. [:!

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F*4' : R"%a)2 T2+! E!(%)"%a%*( P)!(*+*%a%") 576

1'3'7' O%=!) %2+! " E!(%)"%a%*( P)!(*+*%a%"):

1'3'7'1' R*4*0


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T9e Gow areas between t9e plates of a con7entional wire+plate ESP usually 7ary

fro6 5 to 12 inc9es in wi/t9. A recent en9ance6ent in t9ese units 9as been wi/e+

plate spacinJs of up to 2, inc9es. i/e spacin i7es a 9i9er collectin el/

strent9 /ue to t9e resultant increase in space c9are8 a 6ore unifor6 current

/ensity8 an/ 9i9er 6iration 7elocities. %ore 7ariation in t9e /isc9are electro/eeo6etry is also possible wit9 wi/e+plate spacin. 0ecause of t9e increase/

eBciency associate/ wit9 t9is tec9ni;ue8 less plate area is nee/e/8 t9ereby

re/ucin t9e o7erall si=e an/ cost of t9e ESP ?12@.

1'3'7'3' E!(%)"0! Va)*a%*"$:

"n a//ition to t9e rii/ fra6es8 t9ere are se7eral ot9er 7ariations of electro/es t9at

are not as co66on. "n so6e cases8 co6pletely rii/ /isc9are electro/es are

preferre/ o7er wei9te/ wires or rii/ fra6es wit9 wires. #t9er /isc9are electro/e

/esins are s;uare wires8 barbe/ wires8 serrate/ strips of 6etal8 an/ strips of 6etal

wit9 nee/les at reular inter7als. T9e barbs8 serration8 an/ nee/les on t9e /isc9are

electro/es 9elp to establis9 a unifor6 electric el/. "n so6e cases8 Gat plates are

use/ bot9 as /isc9are an/ collection electro/es. ollection electro/es are often

6o/ie/ wit9 baKes to i6pro7e as Gow an/ particle collection. So6e ESPs use

wire 6es9 rat9er t9an Gat plates as collection electro/es. ?@

1'3'7'' C"$(!$%)*( Pa%!:

"n t9is /esin8 t9e ESP consists of 7ertical cylin/ers t9at are arrane/ concentricallyan/ act as collection electro/es. T9e walls of t9e cylin/ers are continually rinse/ by

a t9in l6 of li;ui/ w9ic9 is supplie/ by a syste6 abo7e t9e electro/es. T9e

/isc9are electro/es are 6a/e of wire 6es9 locate/ between t9e cylin/ers. T9is

type of ESP is only operate/ as a wet ESP. T9e as strea6 is wette/ in a scrubber

before it reac9es t9e ESP. ?5@

1'3'7'' P-!0 E$!)4*>a%*"$:

So6e ESPs 9a7e eperience/ success wit9 pulse/ eneri=ation. on7entional ESPs

rely on a constant base 7oltae applie/ to t9e /isc9are electro/e to enerate t9e

corona an/ electric el/. "n pulse eneri=ation8 9i9 7oltae pulses of s9ort /uration

Hof a few 6icrosecon/sI are applie/ to t9e /isc9are electro/es. A typical pulse

eneri=ation syste6 will operate wit9 pulse 7oltaes on t9e or/er of 1,, >ilo7olts

H>VI rat9er t9an t9e *, >V use/ wit9 con7entional eneri=ation. T9e pulses pro/uce

a 6ore unifor6ly current /istribution on t9e collection electro/e. Pulses can be use/

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alone or in a//ition to a base 7oltae an/ 9a7e been s9own to increase t9e

collection eBciency of ESPs wit9 poor eneri=ation. Pulse eneri=ation 9as been

use/ successfully in t9e electric utility in/ustry. T9e "on P9ysics orp. 9as perfor6e/

tests of t9is proce/ure at %a/ison Las an/ Electric8 %a/ison8 isconsin. T9is

tec9ni;ue is8 9owe7er8 still e7ol7in to per6it a 6ore rational approac9 to pulseeneri=ation an/8 per9aps8 to re/uce t9e cost. ?@

1'3'7'7' T/"


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into t9e process8 wet ESPs also 6ay not be /esirable8 since t9e /ust is collecte/ as a

wet slurry t9at woul/ li>ely nee/ a//itional treat6ent. ?5@ ?1,@

Electrostatic precipitators are usually not suite/ for use on processes w9ic9 are

9i9ly 7ariable8 since fre;uent c9anes in operatin con/itions are li>ely to /era/e

ESP perfor6ance. Electrostatic precipitators are also /iBcult to install on sites w9ic99a7e li6ite/ space because ESPs 6ust be relati7ely lare to obtain t9e low as

7elocities necessary for eBcient particle collection. ?@

Typical in/ustrial applications of ESP are as followsF

T2+! " I$0-%)2 T2+! " ESP

U%**%2 B"*!)

?C"a, O*@

DESP8 ire Plate

I$0-%)*a B"*!)

?C"a, O*, ;""0, L*' ;a%!@

DESP8 ire Plate

C"..!)(*aI$%*%-%*"$a B"*!)

?C"a, O*, ;""0@

DESP8 ire Plate

C=!.*(a Ma$-a(%-)! Site Specic

N"$


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F!))"- M!%a P)"(!*$4

1' C"! P)"0-(%*"$

' F!))"


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and construction for long"term, continuous operation while minimi/ing the e8uipment

maintenance needed.


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Scru,,ers

-et Scru,,ers.ry Scu,,ers

''1' D)2 S()-bb!):

A dry or semi"dry scruing system, unlike the wet scruer , does not saturate the flue gas

stream that is eing treated with moisture. #n some cases no moisture is added, while in others

only the amount of moisture that can e evaporated in the flue gas without condensing is added.

herefore, dry scruers generally do not have a stack steam plume or waste"

water handling&disposal re8uirements. ry scruing systems are used to remove acid

gases (such as S1> and


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.ry Scru,,ers

.ry Sor,ent #n4ectors Spray .ryers A,sor,ers

ry scruing systems can e categori/ed as

• ry sorent in4ectors (S#s) or

• Spray dryer asorers, spray dryer asorers are also called semi"dry scruers or

spray dryers.

2.2.1.1. Dr! ,or)ent In-ection:

ry sorent in4ection involves the addition of an alkaline material (usually hydrated lime, soda

ash, or sodium icaronate) into the gas stream to react with the acid gases. he sorent can

e in4ected directly into several different locations% the comustion process, the flue gas duct

(ahead of the particulate control device), or an open reaction chamer (if one e$ists). he acid

gases react with the alkaline sorents to form solid salts which are removed in the particulate

control device. hese simple systems can achieve only limited acid gas (S1> and


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he heat of the flue gas is used to evaporate all the water droplets, leaving a non"saturated flue

gas to e$it the asorer tower. Spray dryers are capale of achieving high (?@ +) acid gas

removal efficiencies. hese devices have een used on industrial and

utility oilers and municipal waste incinerators. [:!

2.2.2. 'et ,cru))ers:

T9e ter6 wet scrubber /escribes a 7ariety of /e7ices t9at re6o7e pollutants fro6

a furnace Gue as or fro6 ot9er as strea6s. "n a wet scrubber8 t9e pollute/ as

strea6 is brou9t into contact wit9 t9e scrubbin li;ui/8 by sprayin it wit9 t9e

li;ui/8 by forcin it t9rou9 a pool of li;ui/8 or by so6e ot9er contact 6et9o/8 so asto re6o7e t9e pollutants. ?1@

he e$haust gases of comustion may contain sustances considered harmful to the

environment, and the scruer may remove or neutrali/e those. A wet scruer is used to

clean air , fuel gas or other gases of various pollutants and dust particles. -et scruing works

via the contact of target compounds or particulate matter with the scruing solution. Solutions

may simply e water (for dust) or solutions of reagents that specifically target certain

compounds.

Process e$haust gas can also contain water"solule to$ic and&or corrosive gases

like hydrochloric acid (


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he condensation of water release significant amounts of low temperature heat (more than >

giga4oules (BC@ k-h) per ton of water), that can e recovered y the cooler for e.g. district

heating purposes. E$cess condensed water must continuously e removed from the circulating

water. he gas leaves the scruer at its dew point, so even though significant amounts of

water may have een removed from the cooled gas, it is likely to leave a visile stack plume of water vapor. [:!

here are different types of wet scruers which are categori/ed on the asis of their use for

particular application or their suitaility for the particular application%

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https://en.wikipedia.org/wiki/District_heatinghttps://en.wikipedia.org/wiki/District_heatinghttps://en.wikipedia.org/wiki/Dew_pointhttps://en.wikipedia.org/wiki/District_heatinghttps://en.wikipedia.org/wiki/District_heatinghttps://en.wikipedia.org/wiki/Dew_point


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2.2.2.1. ,pra! ,cru))ers:

Spray scrubbers are 7ery si6ple8 low+enery wet scrubbers. "n t9ese scrubbers8 t9e

particulate+la/en as strea6 is intro/uce/ into a c9a6ber w9ere it co6es into

contact wit9 li;ui/ /roplets enerate/ by spray no==les. T9ese scrubbers are also

>nown as pre+for6e/ spray scrubbers8 since t9e li;ui/ is for6e/ into /roplets prior

to contact wit9 t9e as strea6. T9e si=e of t9e /roplets enerate/ by t9e spray

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T2+! " S()-bb!)


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no==les is controlle/ to 6ai6i=e li;ui/+particle contact an/8 conse;uently8 scrubber

collection eBciency.

T9e co66on types of spray c9a6bers areF

• Spray towers an/

• yclonic c9a6bers.

Spray towers are cylin/rical or rectanular c9a6bers t9at can be installe/ 7ertically

or 9ori=ontally.

"n 7ertical spray towers8 t9e as strea6 Gows up t9rou9 t9e c9a6ber an/

encounters se7eral sets of spray no==les pro/ucin li;ui/ /roplets. A /e+6ister at

t9e top of t9e spray tower re6o7es li;ui/ /roplets an/ wette/ P% fro6 t9e eitinas strea6. Scrubbin li;ui/ an/ wette/ P% also /rain fro6 t9e botto6 of t9e tower

in t9e for6 of a slurry.

ori=ontal spray c9a6bers operate in t9e sa6e 6anner8 ecept for t9e fact t9at t9e

as Gows 9ori=ontally t9rou9 t9e /e7ice. ?1@ ?15@ ?21@

A cyclonic spray c9a6ber is si6ilar to a spray tower wit9 one 6a


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F*4' 1: C2("$*( S()-bb!)

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F*4' 11: S+)a2 T"/!)

2.2.2.2. Pac/ed Bed ,cru))ers:

Pac>e/+be/ scrubbers consist of a c9a6ber containin layers of 7ariously+s9ape/

pac>in 6aterial8 suc9 as rasc9i rins8 spiral rins8 an/ berl sa//les t9at pro7i/e alare surface area for li;ui/ particle contact. T9e pac>in is 9el/ in place by wire

6es9 retainers an/ supporte/ by a plate near t9e botto6 of t9e scrubber. Scrubbin

li;ui/ is e7enly intro/uce/ abo7e t9e pac>in an/ Gows /own t9rou9 t9e be/. T9e

li;ui/ coats t9e pac>in an/ establis9es a t9in l6.

"n 7ertical /esins8 t9e as strea6 Gows up t9e c9a6ber Hcounter+current to t9e

li;ui/I. So6e pac>e/ be/s are /esine/ 9ori=ontally for as Gow across t9e pac>in

Hcross+currentI. "n pac>e/+be/ scrubbers8 t9e as strea6 is force/ to follow a

circuitous pat9 t9rou9 t9e pac>in8 on w9ic9 6uc9 of t9e P% HParticulate 6attersI

i6pacts. T9e li;ui/ on t9e pac>in collects t9e P% an/ Gows /own t9e c9a6ber

towar/s t9e /rain at t9e botto6 of t9e tower. A 6ist eli6inator Halso calle/ a O/e+

6isterOI is typically positione/ abo7eafter t9e pac>in an/ scrubbin li;ui/ supply.

Any scrubbin li;ui/ an/ wette/ P% entraine/ in t9e eitin as strea6 will be

re6o7e/ by t9e 6ist eli6inator an/ returne/ to /rain t9rou9 t9e pac>e/ be/. "n a

pac>e/+be/ scrubber8 9i9 P% concentrations can clo t9e be/8 9ence8 t9e

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li6itation of t9ese /e7ices to strea6s wit9 relati7ely low /ust loa/ins. Pluin is a

serious proble6 for pac>e/ be/ scrubbers because t9e pac>in is 6ore /iBcult to

access an/ clean t9an ot9er scrubber /esins. %obile+be/ scrubbers are a7ailable

t9at are pac>e/ wit9 low+/ensity plastic sp9eres t9at are free to 6o7e wit9in t9e

pac>e/ be/. T9ese scrubbers are less susceptible to pluin because of t9eincrease/ 6o7e6ent of t9e pac>in 6aterial. "n eneral8 pac>e/+be/ scrubbers are

6ore suitable for as scrubbin t9an particulate scrubbin because of t9e 9i9

6aintenance re;uire6ents for control of P%. ?15@ ?21@

F*4' 1: Pa(!0 B!0

'''3' I.+*$4!.!$% Pa%! S()-bb!):

An i6pine6ent plate scrubber is a 7ertical c9a6ber wit9 plates 6ounte/

9ori=ontally insi/e a 9ollow s9ell. "6pine6ent plate scrubbers operate as

countercurrent P% collection /e7ices. T9e scrubbin li;ui/ Gows /own t9e tower

w9ile t9e as strea6 Gows upwar/. ontact between t9e li;ui/ an/ t9e particle+

la/en as occurs on t9e plates. T9e plates are e;uippe/ wit9 openins t9at allow

t9e as to pass t9rou9. So6e plates are perforate/ or slotte/8 w9ile 6ore co6ple

plates 9a7e 7al7e+li>e openins.

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T9e si6plest i6pine6ent plate is t9e sie7e plate8 w9ic9 9as roun/ perforations. "n

t9is type of scrubber8 t9e scrubbin li;ui/ Gows o7er t9e plates an/ t9e as Gows up

t9rou9 t9e 9oles. T9e as 7elocity pre7ents t9e li;ui/ fro6 Gowin /own t9rou9

t9e perforations. Las+li;ui/+particle contact is ac9ie7e/ wit9in t9e frot9 enerate/

by t9e as passin t9rou9 t9e li;ui/ layer. o6ple plates8 suc9 as bubble cap orbaKe plates8 intro/uce an a//itional 6eans of collectin P%. T9e bubble caps an/

baKes place/ abo7e t9e plate perforations force t9e as to turn before escapin t9e

layer of li;ui/. 9ile t9e as turns to a7oi/ t9e obstacles8 6ost P% cannot an/ is

collecte/ by i6paction on t9e caps or baKes. 0ubble caps an/ t9e li>e also pre7ent

li;ui/ fro6 Gowin /own t9e perforations if t9e as Gow is re/uce/. "n all types of

i6pine6ent plate scrubbers8 t9e scrubbin li;ui/ Gows across eac9 plate an/

/own t9e insi/e of t9e tower onto t9e plate below.

After t9e botto6 plate8 t9e li;ui/ an/ collecte/ P% Gow out of t9e botto6 of t9e

tower. "6pine6ent plate scrubbers are usually /esine/ to pro7i/e operator

access to eac9 tray8 6a>in t9e6 relati7ely easy to clean an/ 6aintain.

onse;uently8 i6pine6ent plate scrubbers are 6ore suitable for P% collection

t9an pac>e/+be/ scrubbers. Particles reater t9an 1Q6 in /ia6eter can be collecte/

eecti7ely by i6pine6ent plate scrubbers8 but 6any particles R1Q6 will penetrate

t9ese /e7ices. ?15@ ?21@

F*4' 13: I.+*$4!.!$% Pa%! S()-bb!)

'''' M!(=a$*(a2 A*0!0 S()-bb!):

%ec9anically+ai/e/ scrubbers H%ASI e6ploy a 6otor /ri7en fan or i6peller to

en9ance as li;ui/ contact. Lenerally in %AS8 t9e scrubbin li;ui/ is spraye/ onto

t9e fan or i6peller bla/es. $ans an/ i6pellers are capable of pro/ucin 7ery ne

Pae 9 of 39


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li;ui/ /roplets wit9 9i9 7elocities. T9ese /roplets are eecti7e in contactin ne

P%. #nce P% 9as i6pacte/ on t9e /roplets8 it is nor6ally re6o7e/ by cyclonic

6otion. %ec9anically ai/e/ scrubbers are capable of 9i9 collection eBciencies8 but

only wit9 a co66ensurate 9i9 enery consu6ption. 0ecause 6any 6o7in parts

are epose/ to t9e as an/ scrubbin li;ui/ in a %AS8 t9ese scrubbers 9a7e 9i96aintenance re;uire6ents. %ec9anical parts are susceptible to corrosion8 P%

buil/up8 an/ wear. onse;uently8 6ec9anical scrubbers 9a7e li6ite/ applications

for P% control. ?15@ ?21@

F*4' 1: M!(=a$*(a2 A*0!0 S()-bb!)

'''' V!$%-)* S()-bb!):

A 7enturi8 or as+ato6i=e/ spray8 scrubber accelerates t9e as strea6 to ato6i=e

t9e scrubbin li;ui/ an/ to i6pro7e as+li;ui/ contact. "n a 7enturi scrubber8 a

Ot9roatO section is built into t9e /uct t9at forces t9e as strea6 to accelerate as t9e

/uct narrows an/ t9en epan/s. As t9e as enters t9e 7enturi t9roat8 bot9 as

7elocity an/ turbulence increase. T9e scrubbin li;ui/ is spraye/ into t9e as

strea6 before t9e as encounters t9e 7enturi t9roat. T9e scrubbin li;ui/ is t9en

ato6i=e/ into s6all /roplets by t9e turbulence in t9e t9roat an/ /roplet+particle

interaction is increase/. After t9e t9roat section in a 7enturi scrubber8 t9e wette/

P% an/ ecess li;ui/ /roplets are separate/ fro6 t9e as strea6 by cyclonic 6otion

an/or a 6ist eli6inator.

Venturi scrubbers 9a7e t9e a/7antae of bein si6ple in /esin8 easy to install8 an/

wit9 low+6aintenance re;uire6ents. T9e perfor6ance of a 7enturi scrubber is

/epen/ent to so6e etent on t9e 7elocity of t9e as t9rou9 t9e t9roat. Se7eral

7enturi scrubbers 9a7e been /esine/ to allow 7elocity control by 7aryin t9e wi/t9

of t9e 7enturi t9roat. 0ecause of t9e 9i9 interaction between t9e P% an/ /roplets8

7enturi scrubbers are capable of 9i9 collection eBciencies for s6all P%.

Pae 3 of 39


31/39

unfortunately8 increasin t9e 7enturi scrubber eBciency re;uires increasin t9e

pressure /rop w9ic98 in turn8 increases t9e enery consu6ption. ?1@

F*4' 1: V!$%-)* S()-bb!)

'''7' O)*(! S()-bb!):

#rice scrubbers8 also >nown as entrain6ent or self+in/uce/ spray scrubbers8 force

t9e particle+la/en as strea6 to pass o7er t9e surface of a pool of scrubbin li;ui/

as it enters an orice. it9 t9e 9i9 as 7elocities typical of t9is type of scrubber8

t9e li;ui/ fro6 t9e pool beco6es entraine/ in t9e as strea6 as /roplets. As t9e

as 7elocity an/ turbulence increases wit9 t9e passin of t9e as t9rou9 t9e

narrow orice8 t9e interaction between t9e P% an/ li;ui/ /roplets also increases.Particulate 6atter an/ /roplets are t9en re6o7e/ fro6 t9e as strea6 by

i6pine6ent on a series of baKes t9at t9e as encounters after t9e orice. T9e

collecte/ li;ui/ an/ P% /rain fro6 t9e baKes bac> into t9e li;ui/ pool below t9e

orice.

#rice scrubbers can eecti7ely collect particles larer t9an 2Q6 in /ia6eter. So6e

orice scrubbers are /esine/ wit9 a/


32/39

wit9 a slu/e ee a con7eyor belt. As t9e slu/e settles to t9e

botto6 of t9e scrubber8 it lan/s on t9e e


33/39

pro7i/e an en7iron6ent t9at encouraes t9e ne P% to coaulate an/ for6 larer

particles.

F*4' 18: C"$0!$a%! S()-bb!) 56

'''' C=a)4!0 S()-bb!):

9are/8 or electrically+au6ente/8 wet scrubbers utili=e electrostatic eects to

i6pro7e collection eBciencies for ne P% wit9 wet scrubbin. Since con7entional

wet scrubbers rely on t9e inertial i6paction between P% an/ li;ui/ /roplets for P%

collection8 t9ey are enerally ineecti7e for particles wit9 /ia6eters less t9an 1Q6.

Pre+c9arin of t9e P% in t9e as strea6 can sinicantly increase scrubber

collection eBciency for t9ese sub 6icro6eter particles. 9en bot9 t9e particles an/

/roplets are c9are/8 collection eBciencies for sub 6icro6eter particles are

9i9est8 approac9in t9at of an ESP.

Pae 33 of 39


34/39

F*4' 1: C=a)4!0 S()-bb!) 516

'3' A++*(a%*"$ " S()-bb!) 5186 516 56:

T2+! " I$0-%)2 T2+! " S()-bb!)

U%**%2 B"*!) ?C"a, O*@ Venturi

I$0-%)*a B"*!)

?C"a, O*, ;""0, L*' ;a%!@

Venturi8 "6pine6ent Plate H0aKeI

C"..!)(*aI$%*%-%*"$a B"*!)

?C"a, O*, ;""0@

Venturi

C=!.*(a Ma$-a(%-)! Pac>e/ 0e/8 Venturi

N"$


35/39

M*$!)a P)"0-(%

C"a C!a$*$4

O%=!)

Venturi

Venturi

;""0, P-+ & Pa+!) Venturi8 yclonic Spray 9a6ber

I$(*$!)a%*"$ ?M-$*(*+a ;a%!@ Venturi8 Pac>e/ 0e/8 on/ensate

F""0 & A4)*(-%-)! "6pine6ent8 Pac>e/ 0e/

3' COMPARISON OF ELECTRSOTIC PRECIPITATOR AND SCRUBBERS

3'1' E!(%)"%a%*( P)!(*+*%a%") 56

A0a$%a4! D*a0a$%a4!

i9 purication eBciency can s9op set

abo7e ,.,1 6icron ne /ust. "n t9e/esin 6ay be /ierent operatin

para6eters8 to 6eet t9e re;uire/

re6o7al eBciency.

E;uip6ent is 6ore co6ple8 re;uires

e;uip6ent transport an/ installation8an/ 6aintenance of 9i9 6anae6ent

le7el.

S6all resistance loss8 usually 2, 66

water colu6n below8 an/ co6pare t9e

cyclone8 e7en consi/erin t9e power

supply unit an/ rappin 6ec9anis6

power8 total power consu6ption is still

relati7ely s6all.

$or /ust resistance t9an t9ere are

certain re;uire6ents8 so t9ere is a

certain selecti7ity of /ust8 not all 9a7e

t9e access to 9i9 /ust re6o7al

eBciency

A"/ =*4=!) "+!)a%*$4

%!.+!)a%-)!, -(= a 0-% SH;B

%2+! (*)(-*% +)!!)ab2 a"/ %=!

"+!)a%*$4 %!.+!)a%-)! " ,

Disappoint6ent te6perature8

te6perature an/ ot9er operatin

con/itions reater i6pact8 t9e sa6e as

a /ust at /ierent te6peratures8

Pae 3 of 39


36/39

%=!)! a)! "%=!) %2+! )!a(=! 3

") =*4=!)'

9u6i/ity operation8 resultin in

/ierent eects8 so6e /ust use/ at a

certain te6perature8 9u6i/ity8 wit9

oo/ results8 w9ile in ot9er at ate6perature an/ 9u6i/ity resistance

c9ane /ue to t9e /ust barely use t9e

ESP.

Processin lare as rane. Ti6e in7est6ent is lare8 9ori=ontal ESP

larer area.

Auto6atic control operation can be fully

reali=e/.

urrently so6e co6panies cannot

reac9 t9e practical eect of t9e /esin

re;uire6ents

3'' S()-bb!) 576

A0a$%a4! D*a0a$%a4!

an 9an/le Ga66able an/ eplosi7e

/ust wit9 little ris>.

i9 potential for corrosion proble6s.

Pro7i/es as absorption an/ /ust

collection in a sinle unit.

ollecte/ particulates 6ay be

conta6inate/ an/ unrecyclable.

Pro7i/es coolin of 9ot ases. Protection aainst free=in is re;uire/.

ertain strea6s 6ay re;uire re+9eatin

to a7oi/ 7isible plu6e.

Pae 37 of 39


37/39

o6pact can often be retrotte/ into

eistin collection syste6.

Disposal of waste slu/e can be 7ery

epensi7e.

orrosi7e ases an/ /usts can be

neutrali=e/.

!e;uires 6a>e up water to replace

pure/ li;ui/ an/ /ispose/ slu/e.

3'3' E("$".*(a A+!(% " ESP & S()-bb!):

D!()*+%*"$ ESP S()-bb!)

I$%aa%*"$ C"% i9 %o/erate

Ma*$%!$a$(! C"% %o/erate ow

P"/!) C"$-.+%*"$ %o/erate to low i9

' REFERENCES:

[! #9PA', Compendium of Chemical Terminology , >nd ed. (the ;6old 7ook;) (**D). 1nlinecorrected version% (>@@C) ;electrostatic precipitator ;.

?2@ 9ttpsFwww.neun/orfer.co6>nowle/ebaseelectrostaticprecipitators.asp

?3@ 9ttpFwww.9itac9i+

infra.co6.sser7icesenery/ustcollectionprinciple/ustcollection.9t6l

Pae 38 of 39

https://en.wikipedia.org/wiki/International_Union_of_Pure_and_Applied_Chemistryhttps://en.wikipedia.org/wiki/Compendium_of_Chemical_Terminologyhttp://goldbook.iupac.org/E02028.htmlhttps://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspxhttp://www.hitachi-infra.com.sg/services/energy/dustcollection/principle/dustcollection.htmlhttp://www.hitachi-infra.com.sg/services/energy/dustcollection/principle/dustcollection.htmlhttps://en.wikipedia.org/wiki/International_Union_of_Pure_and_Applied_Chemistryhttps://en.wikipedia.org/wiki/Compendium_of_Chemical_Terminologyhttp://goldbook.iupac.org/E02028.htmlhttps://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspxhttp://www.hitachi-infra.com.sg/services/energy/dustcollection/principle/dustcollection.htmlhttp://www.hitachi-infra.com.sg/services/energy/dustcollection/principle/dustcollection.html


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?-@ 9ttpFwww3.epa.o7ttncaaat1reportssect*+2.p/f

?*@ 9ttpsFwww.os9a.o7/stopicssilicacrystalline/ustc9apter-.9t6l

?@ 9ttpFwww.9itac9i+

infra.co6.sser7icesenery/ustcollectionspecialpopup1.9t6l

?@ T9e Electrostatic Precipitator %anual H!e7ise/I. T9e %c"l7aine o6pany8

Nort9broo>8 "llinois. %arc9 144.

?5@. ontrol Tec9ni;ues for Particulate E6issions fro6 Stationary Sources + Volu6e 1

HEPA+ -*,3+51+,,*a8 NT"S P053+12-45I. (.S. En7iron6ental Protection Aency8

#Bce of Air 'uality Plannin an/ Stan/ar/s. !esearc9 Trianle Par>8 Nort9 arolina.

Septe6ber 1452.

?4@. Steins7aa8 !. #7er7iew of Electrostatic Precipitators. Plant Enineerin. Uuly 1,8

144*.

?1,@. %astropietro8 T. an/ P. D9aral>ar. Electrostatic Precipitator Desins E7ol7e to6eet Ti9ter !eulations. Pulp & Paper. Septe6ber 1441.

?11@. #lesby8 S.8 Ur. $uture Directions of Particulate ontrol Tec9noloyF A

Perspecti7e. U. Air aste %anae6ent Assoc. -,H5IF 115-+115*. Auust 144,.

?12@. Sc9oltens8 %.U. Air Pollution ontrolF A o6pre9ensi7e oo>. Pollution

Enineerin. %ay 1441.

?13@ 9ttpsFen.wi>ipe/ia.orwi>iScrubber

?1-@ 9ttpFwww.pollutionsyste6s.co6c9e6ical+scrubbers+as+scrubbers.9t6l

?1*@ 9ttpFwww.in/ia6art.co6aircon+syste6sin/ustrial+scrubbers.9t6l

?1@ 9ttpsFen.wi>ipe/ia.orwi>ietscrubber

?1@ ooper8 .D an/ $.. Alley. Air Pollution ontrolF A Desin Approac9. 2n/ e/.

a7elan/ Press8 Prospect ei9ts8 "llinois. 144-.

?15@ T9e Scrubber %anual H!e7ise/I. T9e %c"l7aine o6pany8 Nort9broo>8 "llinois.

Uanuary 144*.

?14@ Perry8 !.. an/ D.. Lreen. Perrys 9e6ical Enineers an/boo> Ht9

E/itionI. %cLrawill Publis9in o6pany8 "nc. New )or>8 New )or>. 145-.

?2,@. Sun8 U.8 0.). iu8 P.. %c%urry8 an/ S. Lreenwoo/. A %et9o/ to "ncrease

ontrol EBciencies of et Scrubbers for Sub6icron Particles an/ Particulate %etals.

U. Air & aste %anae6ent Association. --F2. $ebruary 144-.

?21@. ontrol Tec9ni;ues for Particulate E6issions fro6 Stationary Sources + Volu6e

1 HEPA+ -*,3+51+,,*a8 NT"S P053+12-45I. (.S. En7iron6ental Protection Aency8

Pae 3 of 39

http://www3.epa.gov/ttn/caaa/t1/reports/sect5-2.pdfhttps://www.osha.gov/dsg/topics/silicacrystalline/dust/chapter_4.htmlhttp://www.hitachi-infra.com.sg/services/energy/dustcollection/special/popup1.htmlhttp://www.hitachi-infra.com.sg/services/energy/dustcollection/special/popup1.htmlhttps://en.wikipedia.org/wiki/Scrubberhttp://www.pollutionsystems.com/chemical-scrubbers-gas-scrubbers.htmlhttp://www.indiamart.com/aircon-systems/industrial-scrubbers.htmlhttps://en.wikipedia.org/wiki/Wet_scrubberhttp://www3.epa.gov/ttn/caaa/t1/reports/sect5-2.pdfhttps://www.osha.gov/dsg/topics/silicacrystalline/dust/chapter_4.htmlhttp://www.hitachi-infra.com.sg/services/energy/dustcollection/special/popup1.htmlhttp://www.hitachi-infra.com.sg/services/energy/dustcollection/special/popup1.htmlhttps://en.wikipedia.org/wiki/Scrubberhttp://www.pollutionsystems.com/chemical-scrubbers-gas-scrubbers.htmlhttp://www.indiamart.com/aircon-systems/industrial-scrubbers.htmlhttps://en.wikipedia.org/wiki/Wet_scrubber


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#Bce of Air 'uality Plannin an/ Stan/ar/s. !esearc9 Trianle Par>8 Nort9 arolina.

Septe6ber 1452.

?22@ o6pilation of Air Pollutant E6ission $actors HAP+-2I. Volu6e " H$ift9 E/itionI.

(.S. En7iron6ental Protection Aency8 !esearc9 Trianle Par>8 Nort9 arolina.

Uanuary 144*.

?23@ erner8 0.U. OParticulate et ScrubbinF T9e EBciency Sca6O in t9e Procee/ins

of t9e A&%A Specialty onference on OParticulate %atter ealt9 an/ !eulatory

"ssues HV"P+ -4IO 9el/ on April -+8 144*8 in Pittsbur98 Pennsyl7ania. A&%A8

Pittsbur98 Pennsyl7ania. 144*.

?2-@ Source ateory E6ission !e/uctions wit9 Particulate %atter an/ Precursor

ontrol Tec9ni;ues. Prepare/ for W. oo/ar/8 (. S. En7iron6ental Protection

Aency8 !esearc9 Trianle Par>8 Nort9 arolina HA'SSD"PSLI8 un/er or>

Assin6ent ""+1 HEPA ontract No. 5+,3+,,3-I8 OE7aluation of $ine Particulate

%atter ontrol.O Septe6ber 3,8 144.

?2*@ 9ttpFwww.c9ina+static.co62,1*,21,a/7antaes+an/+/isa/7antaes+of+t9e+

electrostatic+precipitator.9t6l

[email protected];uip6entair;u

alityscrubbers
http://www.china-static.com/2015/02/10/advantages-and-disadvantages-of-the-electrostatic-precipitator.htmlhttp://www.china-static.com/2015/02/10/advantages-and-disadvantages-of-the-electrostatic-precipitator.htmlhttp://www.globalspec.com/learnmore/manufacturing_process_equipment/air_quality/scrubbershttp://www.globalspec.com/learnmore/manufacturing_process_equipment/air_quality/scrubbershttp://www.china-static.com/2015/02/10/advantages-and-disadvantages-of-the-electrostatic-precipitator.htmlhttp://www.china-static.com/2015/02/10/advantages-and-disadvantages-of-the-electrostatic-precipitator.htmlhttp://www.globalspec.com/learnmore/manufacturing_process_equipment/air_quality/scrubbershttp://www.globalspec.com/learnmore/manufacturing_process_equipment/air_quality/scrubbers

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