01-01-2013, 04:10 PM
GENERATION OF THERMAL POWER
Thermal Power Plant
A generating station which converts heat energy of coal combustion into electrical energy is known as a steam power station.
Steam is produced in the boiler by utilizing the heat of coal combustion. The steam is then expanded in the steam turbine and is condensed in a condenser to be fed into the boiler again. The steam turbine drives the alternator which converts mechanical energy of the turbine into electrical energy.
WORKING OF STEAM POWER PLANT
Coal is burnt in a boiler ,which converts water into steam.
The steam is expanded in a turbine used to drive alternator.
The steam expanded is condensed in a condenser to be feed into the boiler again.
The entire arrangement of steam power plant can be divided into :
a. fuel and ash plant.
b. air and fuel gas plant.
c. feed water and steam plant.
d. cooling water plant.
Boiler
A boiler is closed vessel in which water is converted into steam by utilising the heat of coal combustion.
Steam boilers are broadly classified into following two types:
(a) Water tube boilers (b) Fire tube boilers
In a water tube boiler, water flows through the tubes and the hot gases of combustion flow over these tubes. Water-tube boilers are used for high-pressure boilers
Generator
Generator converts the mechanical energy of turbine shaft into electrical energy. Rotating field type generators are employed which are ventilated by the fans of rotor shaft or separately driven fans.
The class of generator under consideration is steam turbine-driven generators, commonly called turbo generators. Generally they have the ratings up to 1900MW but here 3000rpm,50Hz generators are used of capacities 122MW.