steam condesers

7/23/2019 Steam Condesers

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STEAM

CONDENSERS



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



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



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



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



Elements of steam condensing plant



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



Jet Condenser Vs Surface Condenser

(Direct Contact type/Mixed type)

(Indirect Contact type/Non-Mixed type)



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



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



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



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



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



Parallel flow low level Jet condenser



Counter flow low level Jet condenser



High level Jet condenser



Ejector type Jet condenser



Down flow Surface condenser



Central flow Surface condenser



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



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.



Evaporative Surface condenser



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



ffects of air leakage in a condenser

ncrease requ rement o coo ng water

Reduced heat transfer

Corrosion



ethods of obtaining maximum vacuum

team a r e ector

De-aerated feed water

Air tight joints



Vacuum Measurement



Vacuum Efficiency

It is defined as the ratio of actual

acuum.

Maximumvacuum Actual =efficiencyVacuum

⎟ ⎞

⎜⎛

vacuumo a na e

⎟⎟⎟

⎠⎜⎜⎜

⎝

Absolute

Vacuum Actual=efficiencyVacuum⎟ ⎞

⎜⎛

-⎟⎜



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-



Edward’s Air Pump



Two Stage Air Ejector

steam condesers

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