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7/23/2019 Steam Condesers
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STEAM
CONDENSERS
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Definition
Condenser is a device in which steam is
condensed to water at a pressure less thanatmosphere.
Condensation can be done by removing heat
from exhaust steam usin circulatin coolin
water
exchanger in which heat from exhaust steam
s rans erre o c rcu a ng coo ng wa er
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Function
To reduce the turbine exhaust pressure so as
to increase the specific output and henceincrease the plant efficiency and decrease the
specific steam consumption.
To condense the exhaust steam from the
boiler. Thus only make up water is required
o compensa e oss o wa er
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Advantages of condensers in steam power plant
1 H g pressure rat o prov es arger ent a py rop
2 Work out ut er k of steam increases and hence
specific steam consumption decreases
the boiler. This reduces the time of evaporation
4) No feed water treatment is required and hence
re uces e cos o e p an
5) The formation of deposits in the boiler surface
can be prevented with the use of condensate
instead of feed water from outer sources
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Elements of steam condensing plant
1 Condenser 2) Air extraction pump
3) Condensate extraction pump
4) Circulating cooling water pump
5 Hot we
7 Make u water um
8) Boiler feed pump
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Elements of steam condensing plant
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Classification of condensers
1) Jet condensers (or) mixing type
b) Counter flow type (High & Low levels)
c ec or ype
2) Surface condensers (or) non-mixing type a) Down low type
b) Central low type
c) Inverted type
e) Evaporation type
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Jet Condenser Vs Surface Condenser
(Direct Contact type/Mixed type)
(Indirect Contact type/Non-Mixed type)
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Comparison of jet & surface condensersJet Condensers Surface Condensers
1) Cooling water and steam are mixed up
2) Low manufacturing cost
1) Cooling water & steam aren’t mixed up
2) High manufacturing cost
3) Requires small floor space
4) The condensate cannot be used as feed
3) Requires large floor space
4) The condensate can be used as feed
water to o er un ess t s ree rom
impurities
water to o er as t s not m xe w t
cooling water
6) Less power is required for water pump
7 Re uires less uantit of coolin water
6) More power is required for water pump
7 Re uires lar e uantit of coolin water
8) The condensing plant is simple
9) Less suitable for high capacity plants
8) The condensing plant is complicated
9) More suitable for high capacity plants
due to low vacuum efficiency
10)Lower upkeep
as vacuum efficiency is high
10)Higher upkeep
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Jet condensers
Jet condensers are used in small capacity
units where clean fresh water is available in
p en y.
In jet condensers, water is in direct contact
w t ex aust steam. Hence t ese are a so
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Advantages & disadvantages of Jet condensers
1) As a result of effective mixing, it requires less circulating
coo ng wa er
2) Equipment is simple and occupy less space
3) Maintenance is cheap
Disadvantages1) Not suitable for higher capacities
2 Condensate cannot be used as feed water to boiler
3) Air leakages are more
4 Requ res arger a r pump
5) Less vacuum is maintained
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Surface condensers
Surface condensers are used in large
capacity plants
In surface condensers, exhaust steam and
water do not mix together. Hence they are
also called indirect contact type (or) non-
mixed type
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Advantages & disadvantages of surface condensers
1) Can be used for large capacity plantsvan ages
3) Condensate is free from impurities and can be reused asfeed water to boiler
4) Impure water can also be used as cooling medium
5) Air leakage is comparatively less, hence less power isrequired to operate air pump
Disad anta es1) Design is complicated and costly
2) High maintenance cost
3) Occupies more space
4) Requires more circulating water
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Parallel flow low level Jet condenser
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Counter flow low level Jet condenser
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High level Jet condenser
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Ejector type Jet condenser
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Down flow Surface condenser
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Central flow Surface condenser
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Inverted type Surface condenser
In this type of jet condensers, steam enters
at the bottom of the shell and flowsupwards.
.
the bottom where condensate pump is
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egenerative type Surface condenser
The condensers used in a regenerative method of heating
e con ensa e are ca e regenera ve ype con ensers.
In this type of condensers, the condensate after leaving
the condenser is passed through the exhaust steam where
u .
The condensate at high temperature can be reused as
feed water to the boiler.
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Evaporative Surface condenser
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Sources of air in Condenser
Air leakage from atmosphere at the joints
pressure less than atmosphere
Air accompanied with steam from the
feed water
In jet condensers, a little quantity of air
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ffects of air leakage in a condenser
ncrease requ rement o coo ng water
Reduced heat transfer
Corrosion
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ethods of obtaining maximum vacuum
team a r e ector
De-aerated feed water
Air tight joints
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Vacuum Measurement
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Vacuum Efficiency
It is defined as the ratio of actual
acuum.
Maximumvacuum Actual =efficiencyVacuum
⎟ ⎞
⎜⎛
vacuumo a na e
⎟⎟⎟
⎠⎜⎜⎜
⎝
Absolute
Vacuum Actual=efficiencyVacuum⎟ ⎞
⎜⎛
-⎟⎜
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Condenser Efficiency
It is defined as the ratio of differenceetween the outlet and inlet tem eratures
f cooling water to the difference betweene empera ure correspon ng o e
acuum in the condenser and inlet
mperature of cooling water ⎛
⎟ ⎞
⎜⎛
⎟
⎟
⎠⎜
⎜
⎝ eTemperatur
water coolingof =efficiencydenser
⎟⎜ eempera ur n e-
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Edward’s Air Pump
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Two Stage Air Ejector
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