MSBTE DIPLOMA IN MECHANICAL ENGINEERING STEAM CONDENSER

1. UNIT 5- STEAM CONDENSER
MR. DHAMMADIP A. KAMBLE
(M. E. (MECH. DESIGN ENGG.))

2. POSITION OF STEAM CONDENSER

3. DALTON’S LAW OF PARTIAL PRESSURE
Dalton’s law of partial pressures is a gas law which states that the total pressure exerted by a mixture of gases is equal to
the sum of the partial pressures exerted by each individual gas in the mixture. For example, the total pressure exerted by
a mixture of two gases A and B is equal to the sum of the individual partial pressures exerted by gas A and gas B.

4. FUNCTION OF STEAM CONDENSER
 The primary object of a condenser is to maintain a low pressure on the exhaust side of the rotor of steam turbine.
This enables the steam to expand to a greater extent which results in an increase in available energy for conversation
into mechanical work.
 The secondary object of condenser is to supply to the boiler pure and hot feed water, as the condensed steam which
is discharged from the condenser and collect in a hot well can be used over again as feed water for the boiler.
 The use of a condenser in a power plant is to improve the efficiency of the power plant by decreasing the exhaust
pressure of the steam below atmospheric pressure. Another advantage of the condenser is that the steam condensed
may be recovered to provide a source of pure feed water to the boiler and reduce the water softening capacity to a
considerable extent.

5. CLASSIFICATION OF STEAM CONDENSER
 1. Jet condensers (mixing type condensers)
a. Parallel flow jet condenser
b. Counter flow jet condenser (low level)
c. Barometric or high level jet condenser
d. Ejector condenser
 2. Surface condensers (non mixing type condensers)
a. Down flow surface condenser
b. Central flow surface condenser
c. Regenerative surface condenser
d. Evaporative condenser

6. SURFACE CONDENSER

7. SURFACE CONDENSER
 In the diagram below, we can see the cylindrical shape surface condenser which is made off cast iron. In the
condenser, some vessel packed with water tubes. Two vertical perforated tubes are placed two sides of the condenser
and water tubes are fixed with these plates. In the tube, water flows from one direction to another direction. Cooling
water flows in one direction to through the lower half of the tubes and returns in opposite direction through the upper
half of the tubes.
 Working principle of surface condenser is completely different from jet condenser. In surface condenser exhaust
steam and cooling water does not mix up with each other. So condensate remains pure and can be reused in
the boiler. Surface condenser is widely used where limited quantity of water is available like ship, land installation
etc. To use such a condenser, limited quantity of water feed to the boiler again and again.

8. EVAPORATIVE CONDENSER

9. EVAPORATIVE CONDENSER
 It is a Type of Surface Condenser.
 In evaporative surface condensers, the steam enters at the top of the condenser in a series of pipes over which a film
of cold water is falling. At the same time, current of air is made to circulate over the film of water.
 As the air circulates over the water film, it evaporates some of the cooling water. As a result of this rapid
evaporation, the steam circulating inside the series of pipes gets condensed.
 Remaining cooling water that left is collected at an increased temperature and reused. It is brought to the original
temperature by adding required quantity of cold water.

10. EJECTOR CONDENSER

11. EJECTOR CONDENSER
 In ejector condensers, it has a non-return valve through which exhaust steam enters, hollow truncated cones, and
diverging cone.
 In these condensers, the cooling water is injected at the top. The steam enters into the condenser through a non-
return valve.
 The steam and water mixes with each other while passing through series of hollow truncated metal cones and steam
changes into water.
 At the end of the metal cones a diverging cone is present. When the condensate passes through diverging cone, its
kinetic energy is partly transformed into pressure energy.
 The condensate and cooling water is then discharged to the hot well.

12. COMPARISON BETWEEN JET CONDENSER AND SURFACE
CONDENSER

13. SOURCES OF AIR LEAKAGE IN CONDENSER
 Air leakage through Joints
Air leakage can take place through various joints, packing and glands due to the high vacuum in the condenser. We
can prevent this by using vacuum joints and keeping all the joints tight and sealed.
 Air dissolved in feed water
When air dissolved feed water enters into the boiler and after the conversion of feed water into steam, it enters
the condenser along with the exhaust steam which causes air leakage in the condenser. We can prevent this by
treating the feed water before entering the boiler.
 Leakage through packing glands and very small holes in the shell.

14. EFFECT OF AIR LEAKAGE IN CONDENSER
 Air leakage can reduce the vacuum pressure of the condenser, which can reduce its useful work done.
 We know that air is a poor conductor of heat, and the presence of air in the condenser can reduce the heat
transformation rate.
 Air leakage increases the power required to drive the air pump for the extraction of air.
 Air leakage leads to the lower partial pressure of steam and therefore more cooling water will be required in the
condenser.

15. CONDENSER EFFICIENCY
 It is defined as the ratio of temperature rise of cooling water to the vacuum temperature minus inlet cooling water
temperature.
to- Outlet temperature of cooling water
tv- Vacuum temperature
ti- Inlet temperature of cooling water

16. VACUUM EFFICIENCY
 It is defined as the ratio of actual vacuum to the ideal vacuum.
Vacuum Efficiency= Actual Vacuum/Ideal Vacuum
Actual Vacuum= Barometric pressure-Actual Pressure
Ideal Vacuum= Barometric pressure-Ideal Pressure

17. COOLING TOWER
 The function of cooling tower is to cool the hot water
from the condenser by exposing it to the atmospheric
air, so that the cold water may be used again to
circulation.

18. NATURAL DRAUGHT COOLING TOWER

19. NATURAL DRAUGHT COOLING TOWER

20. NATURAL DRAUGHT COOLING TOWER
 Working Principle - The hot water that is to be cooled in the cooling tower is pumped to the top of the
cooling tower at the hot water inlet.
 The hot water inlet is connected to a series of nozzles which spray this water over the fill material
(provides a large contact surface area for heat transfer).
 Fresh air is induced by the open structure at bottom of the tower and then the air flows in the upward
direction for direct contact heat transfer between warm water and air.
 The hot water liberates heat after direct contact with fresh air and some of the water gets evaporated and
cold water gets collected at the bottom of the tower.
 Warm and moist air will be discharged from the top of the tower into the atmosphere.

21. NATURAL DRAUGHT COOLING TOWER
 Advantages
1. No electrical fan is installed so power saving
2. No corrosion problems
3. Maintenance is low
4. No recirculation of air occurs due to high stack outlet
 Disadvantages
1. Huge water flow required.
2. These require a large area.
3. Its performance depends on wind velocity and direction.

22. FORCED DRAUGHT COOLING TOWER

23. FORCED DRAUGHT COOLING TOWER

24. INDUCED DRAUGHT COOLING TOWER

25. INDUCED DRAUGHT COOLING TOWER