The steam can be condensed in surface steam condenser in two ways.
Firstly, cooling water is passed through a series of tubes and steam
passes over the tubes.
Secondly, the steam is passed through a series of tubes and water is allowed to flow in the form of thin film outside the tubes.
A surface condenser mainly consists of a cast iron shell. The shell is cylindrical in shape and closed at both end to form a water box. A tube plate is located between each cover head and the shell. A number of water tubes are fixed to the tube plates. The shell is provided with exhaust steam inlet at the top and condensed steam outlet at the bottom. The hot exhaust steam enters through the top inlet of the surface condenser shell cooling water enters into the inlet water box and then flows through the water tubes runs from one end to other end of the condenser shell as shown. Then it enters into the end water box and returns from this box to outlet water box via return water tubes. During this circulation, the heat is absorbed from exhaust steam by cooling water through the wall of the tubes. As a result, the steam ultimately becomes condensed and comes out through wet air outlet.
This surface condenser required two pumps-
1) One pump to circulate cooling water through the water tubes under pressure.
2) One for extracting wet air, condensates from the bottom of the condenser shell.
Surface steam condensers are of mainly two types :
1) Two flow condenser.
2) Multi flow condenser.
In two flow steam condenser, cooling water travels twice once from inlet-water box to end water box and once from end water box to outlet water box. Two flow condenser is already discussed.
By providing more and more partitions in the water boxes, surface condenser can be made multi flow condenser like, 4 flow, 6 flow etc. In multi-flow process, the rate of heat exchange is rapid but the power required to circulate the cooling water is also more.
According to the direction of flow of steam the surface steam turbine can be classified as- 1) Down flow
2) Central flow
3) Inverted flow surface condenser.
Secondly, the steam is passed through a series of tubes and water is allowed to flow in the form of thin film outside the tubes.
A surface condenser mainly consists of a cast iron shell. The shell is cylindrical in shape and closed at both end to form a water box. A tube plate is located between each cover head and the shell. A number of water tubes are fixed to the tube plates. The shell is provided with exhaust steam inlet at the top and condensed steam outlet at the bottom. The hot exhaust steam enters through the top inlet of the surface condenser shell cooling water enters into the inlet water box and then flows through the water tubes runs from one end to other end of the condenser shell as shown. Then it enters into the end water box and returns from this box to outlet water box via return water tubes. During this circulation, the heat is absorbed from exhaust steam by cooling water through the wall of the tubes. As a result, the steam ultimately becomes condensed and comes out through wet air outlet.
This surface condenser required two pumps-
1) One pump to circulate cooling water through the water tubes under pressure.
2) One for extracting wet air, condensates from the bottom of the condenser shell.
Surface steam condensers are of mainly two types :
1) Two flow condenser.
2) Multi flow condenser.
In two flow steam condenser, cooling water travels twice once from inlet-water box to end water box and once from end water box to outlet water box. Two flow condenser is already discussed.
By providing more and more partitions in the water boxes, surface condenser can be made multi flow condenser like, 4 flow, 6 flow etc. In multi-flow process, the rate of heat exchange is rapid but the power required to circulate the cooling water is also more.
According to the direction of flow of steam the surface steam turbine can be classified as- 1) Down flow
2) Central flow
3) Inverted flow surface condenser.
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