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Statement I: The condenser in a steam power plant is always filled with a mixture of water, steam and air. Statement II: Slightly wet steam enters the condenser wherein the pressure is below the atmospheric conditions, causing some leakage of air through the glands and also the release of some air dissolved in the boiler feed water.

Statement I: The condenser in a steam power plant is always filled with a mixture of water, steam and air. Statement II: Slightly wet steam enters the condenser wherein the pressure is below the atmospheric conditions, causing some leakage of air through the glands and also the release of some air dissolved in the boiler feed water. Correct Answer Both Statement I and Statement II are individually true, and Statement II is the correct explanation of Statement I

Condenser: The exhaust steam from the turbines is condensed in the condensers, condensers operates at a pressure lower than the atmosphere. The cooling water is used as coolant to remove the heat from the exhaust steam.

The objectives of the condenser are

  • To reduce the turbine exhaust pressure so as to increase the specific output of the turbine.

  • To recover high quality feed water in the form of the condensate and feed it back to the steam generator without any further treatment.


The pressure is below the atmospheric pressure in the condenser which creates the possibility of the air leakage into the condenser. Therefore the condensers in a steam plant is always filled with mixture of water steam and air due to the pressure being lesser than the atmospheric pressure. 

A steam jet air ejector removes the non-condensable gases from the feed water.

Therefore both the statements are individually true and statement II) is the correct explanation of statement I).

The condensers are basically of two types:

Direct contact condensers: In these type of condensers the condensate and cooling water directly mix and come out as a single stream.

These are of three types:

  • Spray condenser

  • Barometric Condenser

  • Jet condenser


Surface condensers: In these type of condensers shell-and-tube type heat exchangers are used where two fluids do not come in direct contact and the heat released by the condensation of steam is transferred through the walls of the tubes into the cooling water continuously circulating inside them. 

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