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INTRODUCTION TO CONDENSER

BY

MNSE, MNIMechE, Regd. Engr. COREN

ENGR. E. A. ABHULIMEN


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'(&ER COO)E* CON*ENSR


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(n air cooled condenser


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&he !ur!ose of a condenser is to condense the

outlet #or exhaust$ steam from steam tur"ine to

o"tain maximum efficienc% and also

&o get the condensed steam in the form of !ure

water, otherwise nown as condensate,#condensate+not to "e mistaen with usage of

the word condensate in Natural gas condensate

in !etroleum industr%$, "ac to steam generatoror #"oiler$ as "oiler feed water.


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( condenser is where the exhaust steam from

the tur"ine is condensed.&he Condenser o!erates at a !ressure lower

than

atmos!heric.&here are two reasons of using a Condenser in a

Steam tur"ine

&o reduce the tur"ine exhaust !ressure so as to

increase the s!ecific out!ut of the tur"ine.

( condenser, "% lowering the "ac !ressure

from -.-/ to .01 "ars, increases the !lant


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&he lower the !ressure, the greater the out!ut and

efficienc%.

&he steam tur"ine itself is a device to convert the heat insteam to mechanical !ower.

&he difference "etween the heat of steam !er unit

weight at the inlet of tur"ine and the heat of steam

!er unit weight at the outlet of tur"ine re!resents

the heat given out #or heat dro!$ in the steam tur"ine

which is converted to mechanical !ower.

&he heat dro! !er unit weight of steam is also measured

"% the word enthal!% dro!. &herefore the more the

conversion of heat !er !ound #or ilogram$ of steam to

mechanical !ower in the tur"ine, the "etter is its


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the wor done "% the s%stem during one c%cle is equal to

the area enclosed "% the heat c%cle diagram.


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Rankine cycle with superheat


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2% condensing the exhaust steam of tur"ine,

the exhaust !ressure is "rought down "elowatmos!heric !ressure from a"ove atmos!heric

!ressure, increasing the steam !ressure dro!

"etween inlet and exhaust of steam tur"ine.

&his further reduction in exhaust !ressure

gives out more heat !er unit weight of steam

in!ut to the steam tur"ine, for conversion to

mechanical !ower.


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3ence, it is im!ortant to use the lowest !ossi"le

Cooling water tem!erature rise of Coolingwater in the Condenser tu"es to 4+56 so that

the tu"e outer surface tem!erature remains low

and consequentl% the Condensing steam

tem!erature is low and 7acuum is high, to

receive high qualit% feed water in the form of

condensate and feed it "ac to the steam

generator without an% further treatment.

Most of the heat li"erated due to condensing,

i.e., latent heat of steam, is carried awa% "% the

cooling medium. #water inside tu"es in a


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The Condenser Unit consists of the

following

!rts"

-$ &he Shell tu"es of the Condenser

8$ &he 'ater "oxes/$ &he Condenser Casing

1$ &he tem!erature gauges

4$ &he Exhaust hood

9$ &he hot well


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&he shell is the outer most "od% of the condenser

!roviding arrangement for installation of tu"es. &he

shell is fa"ricated from fairl% thic car"on steel !lates.

*ue to its large si:e the shell is sufficientl%

strengthened or stiffened internall% with car"on steel

!lates to give sufficient rigidit% for the shell !ro!er.

&he shell also gives su!!ort to num"er of intermediatesu!!ort !lates for the long tu"es, de!ending on the si:e

of the condenser. &hese intermediate tu"e su!!ort

!lates also hel! to avoid the sagging of long length of

tu"es.


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&hese su!!ort !lates have sufficient num"er of

holes of suita"le diameter drilled with the hel!

ofa ;ig in a suita"le drilling machine to facilitate

the eas% threading of each and ever% tu"e during

installation or during re!lacements.

(t the same time the intermediate tu"e su!!ort

!lates allow for the free movements of tu"es in

all directions !articularl% lengthwise due to

ex!ansion and contraction occurring during

o eration.


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&he shell is connected to the outlet #exhaust$ of the

steam tur"ine "% means of an ex!ansion ;oint made

generall% of stainless steel, flanged at "oth ends.

&he whole condenser is su!!orted on heav% s!rings,

mounted on steel sole !lates at suita"le !laces on the

concrete foundation, normall% with a slight inclination

towards the outlet water "ox to assist com!lete water"ox drainage.

(t the "ottom of the shell where the condensate is

allowed to collect, a sum! #often referred to as the

hotwell$ is !rovided.


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&his sum! is common to "oth the halves "ut

se!arated "% a !artition wall in the middle u! tothe height of the "ottom row of tu"es.

&his is to facilitate the measurement ofconductivit% of condensate on "oth sides

inde!endentl%.

&his is to detect contamination of condensate

and from which half side it is.


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CONDEN#ER DE#IGN AND MAINTENANCE

DE#IGN CON#TRUCTION O$ THE #UR$ACE CONDEN#ER

&he figure "elow de!icts a schematic illustration of the

flow of steam, condensate and cooling water in the

condenser.

Cooling water #or circulating water$ taen from a river

is !um!ed to the condenser.It enters a water+"ox in the condenser as shown on the

left+hand side and flows through the condenser tu"es to

the water+"ox on the other end,

the cooling water is then discharged "ac to the canal.

&he water ee!s the outside surfaces of the condenser

tu"es cool at all times when the tur"ine is in o!eration.


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Steam from the tur"ine exhaust enters the condenser at

the to! and flows in "etween the condenser tu"es. (s

the steam !asses over the cone tu"es, it condenses and

dri!s down to the "ottom of the condenser where it is

collected in what is called a hot+well.

In the surface t%!e of condenser, there is no direct

contact "etween the steam and cooling water. 'hensteam condenses, it gives u! a large quantit% of heat.

&his quantit% of heat is a"sor"ed "% the cooling water

and carried awa%.


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&he next figure shows an end view of the inside

of a surface condenser.

Each of the small circles re!resents the endview of a condenser tu"e.

Steam can flow in all the s!ace "etween the

tu"es.&he tu"es are arranged in grou!s or "ans with

wide lanes in "etween "ans.

'ith the wide lane !resent, a ma;or !ortion ofthe steam can flow right down to the "ottom

half of the condenser and the cooling ca!acit% of

all the tu"es can "e used effectivel%.


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AIR E%TRACTION

$ig&re ' !(o)e h!s !n !ir s&ction connection !t either side.

&hese connections are there for a s!ecific

!ur!ose. 'ater generall% dissolves air and non+

condensa"le gases which can "e quite corrosive

to metal. Ox%gen is one of the more serious

offenders in this regard. 2ecause of the near

!erfect vacuum conditions in the condenser,

thereis a tendenc% for air to lea in at an% ;oint which

is not sealed tightl%.

In order to !revent the air and non+condensa"le

S/NO MATERIAL


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S/NO

.

MATERIAL

COMPOSITION

1. Admiralty Brass 70%, Cu, 1% Tin, 2% Arsenic,

Remainder n.

2 Aluminum Brass 7!% Cu, 2% A1, Arsenic,

Remainder n

" Cupr#$ickel !&% Cu, "0% ickel, 1%

'an(anese, 1% )e.

* +tainless +teel r#n and Car-#n

/i(h Tin Br#ne &7.% C#pper, 12. Tin.


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U#E#E O$ THE MATERIAL#

ALUMINIUM BRA## * U#E#"

#a$


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+ROBLEM# ENCOUNTERED IN CONDEN#ER O+ERATION

&he ma;or !ro"lems encountered in a condenser are

highlighted "elow

)eaage of cooling water into steam s!ace,

Corrosion of tu"es,Erosion of tu"es and

=ouling of the mouth of condenser tu"es


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LEA-AGE O$ COOLING /ATER INTO #TEAM #+ACE

&his occurs when there are cracs in condenser tu"es.

CORRO#ION O$ TUBE#

Corrosion is a !rocess of wastage "% electro+chemical

action taing the form of>

?eneral wastage.

*e!osit attac.

Im!ingement attac.

ERO#ION O$ TUBE#&his is a mechanical weathering. It occurs "oth inside

and outside of condenser tu"es.

$OULING O$ THE MOUTH O$ CONDEN#ER TUBE#


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CAU#E# O$ CONDEN#ER TUBE $AILURE

&he following factors are res!onsi"le for

condenser tu"e failure>

-. Erosion.

8. Corrosion.


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METHOD# ADO+TED TO O0ERCOME CONDEN#ER

+ROBLEM#

-.@ro!er selection

8.@ro!er design of water+"ox to eliminate tur"ulence.

/.Chlorine treatment to com"at marine growth.

1.Selection of suita"le cooling, water velocit%.

4.@rovision of im!ingement "affles at !oints of entr% ofsteam into condenser.

9.@eriodic cleaning of condenser "% the following

methods>

i$2rush cleaning with steel wire "rush or N%lon

"rush with water flushing,

ii$'ater ;et cleaning

iii$ On load cleaning with s!onge "all in circulation.


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CONDEN#ER IN#+ECTION AND MAINTENANCE

'hen the two main air e;ectors cannot maintain

vacuum after !ro!er cleaning of the no::les and re!airs,there is a tendenc% to sus!ect condenser tu"e fouling.

In this regard,

Condenser ins!ection is carried out during unit shut+down for !lanned outage ;o"s.

&he following condenser ins!ection are carried out>

#a$'ater side fouling

#"$Steam side fouling

#c$(ccumulation of dirt on the floor of the steam s!ace.

#d$&u"e sheet fouling.


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/ATER #IDE $OULING

Organic growth as slime is the main factor in condenser

fouling. &he slim% matter stics to the inside surface of

the tu"e and has the "linding effect to sus!end solids

and silt which are !oor condensers of heat.

&his increases the terminal tem!erature difference in

turn resulting in increased "ac !ressure. &he !ro"lemis overcome "% condenser tu"e cleaning.

#TEAM #IDE $OULING

&u"e fouling on steam side can occur if feed water

qualit% is not maintained at the sti!ulated level and

there is contamination of steam.

&his fouling which is rare has the same effect as the

fouling of inside of condenser tu"es. &he !ro"lem is


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TUBE #HEET $OULING

&u"e sheet fouling is caused "% de"ris fish

shelletc. in the circulation water. &hese

"loc the mouth of the condenser tu"es and

causeo"struction to the flow of water.

&his results in circulating water

tem!erature rise and consequent increase in "ac

!ressure.

&he !ro"lem is overcome "% removing the

de"ris on the water side of circulatin water


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ACCUMULATION O$ DIRT ON THE $LOOR O$ THE

#TEAM #+ACE

&he floor of the steam s!ace is cleaned with

demineralised water in order to remove dirt and rust

formed on the floor.

DIRT1 HOT,/ELL #TRAINER

&he strainer in the hot+well is removed, cleaned and

!ut "ac during condenser ins!ection.


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CONDENSER REPAIR:

CONDEN#ER TUBE RENE/AL

&his can "e done during shut down of unit.@rocedure>

-. 'ater "ox doors and manholes are o!ened.

8. &u"es are com!letel% air dried.

/. )eaing tu"es are alread% detected, !lugged

and are clearl% mared for renewal.1. Steam side is drained.

4. 2oth the ends of the tu"es are colla!sed with a

crum!ing tool.


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0. &he tu"e has to "e taen out "% hand "% twisting,

twigging and !ulling out.

5. ( new tu"e is carefull% inserted.A. (t the inlet end, the tu"e is left !rotruding out of the

tu"e sheet "% a"out 9./4mm and the rest extends out at

the other end.

-. &he tu"es are ex!anded at "oth ends with a tu"e

ex!ander, taing care against over ex!ansion #tu"e

getting weaened$ or under ex!ansion #giving room for

see!age$.

--. &he inlet end of the tu"e is flared giving it a "ell+

mouth sha!e.

-8. &he condenser steam s!ace is filled with water and


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