Applied thermodynamics steam condensers unit four

Steam condensers

1. STEAM CONDENSERS
FIG: STEAM POWER PLANT

2. STEAM CONDENSERS
Condenserisaheattransferdeviceinwhich
theexhauststeamofaturbineiscondensedby
meansofcoolingwateratpressurebelow
atmosphericpressure.

3. CONDENSATION -Definition
Condensationisaprocessinwhichsteamis
condensedtowateratapressurelessthan
atmosphere.
Condensationcanbedonebyremovingheat
fromexhauststeamusingcoolingwater.
Duringthistheworkingfluidchangesitsphase
fromvapourtoliquidandrejectsitslatentheat.

4. CONDENSATION -Functions
Toreducetheturbineexhaustpressuresoasto
increasethespecificoutputandhenceincreasethe
plantefficiency.
Tocondensetheexhauststeamfromturbineand
reuseitasfeedwaterinboiler.
Itenablestoremoveofairandothernon
condensablegasesfromsteam.Henceheattransfer
ratecanbeimproved.

5. CONDENSATE
ThecondensedSteamiscalledCondensateandcanbe
againreturnedtoBoiler.Itsavesthecostofwater.

6. PRINCIPLE OF CONDENSATION
•Inordertoattain
maximum work,
accordingtoCarnot
principle,theheat
mustbesuppliedat
Maximum pressure
andtemperatureand
shouldberejectedat
Minimumpressureand
temperature.
V

7. ADVANTAGES OF CONDENSERS
•Itincreasestheworkoutputperkgofsteamsupplied
tothepowerplant.
•Reducesthespecificsteamconsumption.
•Reducesthesizeofpowerplantofgivencapacity.
•Improvesthethermalefficiencyofpowerplant.
•Savesthecostofwatertobesuppliedtoboiler.

8. ELEMENTS OF CONDENSING
PLANT

9. ELEMENTS OF CONDENSING
PLANT

10. ELEMENTS OF CONDENSING PLANT
•AIREXTRACTION PUMP:
Toremoveairfromthe
condenser,suchapumpis
calleddryairpump.Ifair
andcondensatebothare
removed,itiscalledaswet
airpump.
•CIRCULATING PUMP:Used
tosupplyfeedwatereither
fromriverorfromthe
coolingtowerpondtothe
condenser.

11. ELEMENTS OF CONDENSING PLANT
•COOLINGTOWER:
1.TheFerroconcretemade
device (hyperbolic
shape)inwhichthehot
water from the
condenseriscooledby
rejectingheattocurrent
ofairpassinginthe
counterdirection.
2.Ringtroughsareplaced
8-10mabovetheground
level.

12. TYPES OF CONDENSERS
•JET CONDENSERS
Theexhauststeamand
coolingwatercomeindirect
contactandasaresultthe
steamiscondensed.Itis
alsocalleddirectcontact
condensers.
•SURFACE CONDENSERS
Thecoolingwaterflows
throughanetworkoftubes
andtheexhauststeam
passesoverthesetubes.
Thesteamgetscondensed
duetoheattransferto
coolantbyconductionand
convection.

13. COMPARISION
S.No
Jet condensers
1. Steamandwatercomesin
directcontact.
2. Condensationisduetomixing
ofcoolant.
3. Condensateisnotfitforuseas
boilerfeeduntilthetreated
coolingwaterissupplied.
4. Itischeap.Doesnotaffectplant
efficiency.
5. Maintenancecostislow.
6. Vacuumcreatedisupto600
mmofHg.
Surface condensers
Steamandwaterdoesnotcomein
directcontact.
Condensationisduetoheattransfer
byconductionandconvection.
Condensateisfitforreuseasboiler
feed.
Itiscostly.Improvestheplant
efficiency.
Maintenancecostishigh.
Vacuumcreatedisupto730mmof
Hg.

14. JET CONDENSERS

15. CLASSIFICATION OF JET CONDENSERS
1.LowLevelJetCondensers
i)CounterFlowType
ii)ParallelFlowType
2.HighLevelJetCondensers
3.EjectorJetCondensers

16. 1.(i)LOW LEVEL COUNTER FLOW JET INJECTOR

17. 1.(ii)LOW LEVEL PARALLEL FLOW JET INJECTOR
•ExhaustSteam&cooling
waterbothflowinsame
direction
•The mixture of
condensate,coolantand
airareextractedwiththe
helpofwetairpump.
•Vacuumcreatedinthe
condenserlimitsupto
600mmofHg.

18. 2.HIGHLEVEL JETCONEDNSER/
BAROMETRIC JETCONDENSER
•Itisalso called
Barometricjetcondenser
sinceitisplacedabove
theatmosphericpressure
equivalentto10.33mof
waterpressure.
•Condensate extraction
pumpisnotrequired
becausetailpipehas
incorporatedinplaceof
it.

19. LOW LEVEL VSHIGH LEVEL

20. EJECTOR

21. 3. EJECTOR JET CONDENSER
•The coolingwater
entersthetopofthe
condenser atleast
underaheadof6mof
waterpressurewith
thehelpofcentrifugal
pump.
•Thissystemissimple,
reliableandcheap.
•Disadvantageofmixing
ofcondensatewiththe
coolant.

22. SURFACE CONDENSERS

23. Surface condensers are of two types
•SURFACE
CONDENSERS
Inthissteamflows
outsidethenetworkof
tubesandwaterflows
insidethetubes.
•EVAPORATIVE
CONDENSERS
Inthiscondensershell
isomitted.Thesteam
passes through
condensertubes,the
waterissprayedwhile
theairpassesupward
outsidethetube.

24. CLASSIFICATION OF SURFACE CONDENSERS
•Thenumberofwater
passes:
1.Singlepass
2.Multipass
•The directionof
condensateflowand
tubearrangement:
1.Downflowcondenser
2.Central flow
condenser

25. SINGLE PASS SURFACE
CONDENSER
STEAM IN
CONDENSATE OUT
COOLING WATER
COOLING WATER

26. DOUBLE PASS SURFACE
CONDENSER
STEAM IN
CONDENSATE OUT
COOLING WATER

27. DOUBLE PASS SURFACE CONDENSER
•Itconsistofair
tightcastiron
cylindricalshell.
•Ifcoolingwateris
impure,condenser
tubesaremadeup
ofredbrass.

28. DOWN FLOW SURFACE CONDENSER
•Thiscondenseremploystwo
separate pumps forthe
extractionofcondensateandthe
air.
•Bafflesareprovidedsothatthe
airiscooledtotheminimum
temperature beforeitis
extracted.
•Thespecificvolumeofcooledair
reduces,thereby,reducesthe
pumpcapacitytoabout50%.
Therefore,italsoreducesthe
energyconsumptionfrorunning
theairpump.

29. CENTRAL FLOW SURFACE CONDENSER
•Airextraction
pumpislocated
atthecentreof
thecondenser
tubes.
•Condensate is
extractedfrom
thebottomof
thecondenser
withthehelpof
condensate
extraction
pump.
•Provides the
bettercontactof
steam.

30. EVAPORATIVE CONDENSER
•Theexhauststeamispassed
throughtheseriesofgilled
tubescalledcondensercoils.
•Thinfilmofcoolingwater
tricklesoverthesetubes
continuously from water
nozzles.
•Duringthecondensationof
steam,thisthinfilmofwateris
evaporatedandtheremainder
wateriscollectedinthewater
tank.
•Thecondensateisextracted
withthehelpofwetairpump.
•Theairpassingoverthetubes
carriestheevaporatedwaterin
theformofvapouranditis
removedwiththehelpof
induceddraftfaninstalledat
thetop.

31. MERITS AND DEMERITS OF JET CONDENSERS
•MERITS
1.Lessquantityofcooling
waterisrequiredto
condensethesteam.
2.Simpleinconstruction
andlowincost.
3.Does not require
coolingwaterpump.
4.Lessspaceisrequired.
5.Lowmaintenancecost.
•DEMERITS
1.Thecondensateisa
waste.
2.Lesssuitableforhigh
capacityplants.
3.Largelengthofpipes
required,hencepiping
costishigh.
4.Lossofvacuumdueto
leakageofairfromlong
pipings.

32. MERITS AND DEMERITS OF SURFACE CONDENSERS
•MERITS
1.Nomixingofcoolingwater
andsteam,hencethe
condensate directly
pumpedintotheboiler.
2.Anykindoffeedwatercan
beused.
3.Developshighvacuum,
thereforesuitablefrolarge
powerplants.
4.Requirelesspowertorun
theairextractionand
waterextractionpump.
5.Systemismoreefficient.
•DEMERITS
1.Requirelargequantityof
coolingwater.
2.System iscomplicated,
costlyandrequireshigh
maintenancecost.
3.Requirelargefloorspace
sinceitisbulky.

33. THANK YOU
IV UNIT COMPLETED