STEAM POWER PLANT

The layout of a steam power plant is given in Fig

• Steam from the boiler is taken to the turbine through the steam pipe fitted with an expansion joint.

• The joint provides a flexible connection to prevent any crack in the steam pipe which   is  subjected  to   expansion  and  contraction  due  to  the  variation  of temperature.

• From the turbine, the steam enters a condenser, details of which are shown in Fig.   In the condenser, the exhaust steam from the turbine is condensed due to which a high vacuum is produced.

• Due to the vacuum, the power output and the thermal efficiency of the turbine are considerably in creased.

• In the condenser, cooling water is circulated by a pump through the water tubes to condense the exhaust steam.

• The cooling water at the outlet becomes hot and it is taken to a cooling pond or a cooling tower to cool and to recalculate the same water if the power plant is not located on the bank of a river or a lake.

The condensate from the condenser before entering the boiler is subjected to the
following treatments.

1. Removal of air and oxygen

2. Preheating the feed water in different stages using low pressure heater (LPH) deaerator
and high pressure heater (HPH).

Air and oxygen are removed at the air ejector and the deaerator. In case, air and oxygen
are not removed from the feed water, the vacuum cannot he main tained in the condenser, resulting in loss of power and thermal efficiency.

Factors to be Considered in the Selection of a- Site for a Steam Power Plant

1.  The  location  of  the  plant  should  be  at  a  minimum  distance  from  the  load  centre
(consumer) to avoid transmission losses.

2. Availability of water is a desirable factor.

3. The water should be preferably free from salt to reduce the cost for water treatment.

4. The soil should be satisfactory for a strong foundation.

5.  The  site  should  be  away  from  the  thickly  populated  area  to  reduce  the  effect  of pollution.