3. THESE THE ACTUAL LAYOUT OF
INDUSTRY
FIG: Dr .Narla Tata Rao Thermal Power Station
4. COAL HANDLING PLANT
The coal supply to the bunkers is being fed to mills / pulverized through belt feeders. In the pulverized
the coal is crushed into fine power and the coal power is supplied to boiler through conveying air by
means of primary air fans.
The coal handling plant can broadly be divided into three sections
1) Wagon Unloading System.
2) Crushing System.
3) Conveying System.
IMAGE OF WAGON UNLOADING SYSTEM
6. BOILER
5.1 INTRODUCTION
A boiler (steam generator) is a closed vessel in which water, under pressure is
converted into steam. It is one of the major components of a thermal power plant. A boiler is
always designed to absorb maximum amount of heat released in process of combustion.
This is transferred to the boiler by all the three modes of heat transfer i.e. conduction,
convection and radiation.
1. Radiation- Which is the transfer of heat from hot body to cold body without
medium.
2. Convection- The transfer of heat through a conveying medium. such as air or water.
3. Conduction- The transfer of heat by an actual physical contact. Heat transfer in the
boiler takes place through radiation and convection processes
7. There are two types of boiler based upon the construction and the number of the steam
passes they are:
1.Tower type boiler
2.Two pass boiler.
BOILERS CLASSIFICATION
A) Fire tube boiler -
In this type, the products of combustion pass through the tubes
which are surrounded by water. These are economical for low pressure
only.
B) Water tube boiler -
In this type of boiler water flows inside the tubes and hot gases
flow outside the tubas. These tubes are interconnected to common water
channels and to steam outlet
8. Turbine is a machine in which a shaft is rotated steadily by impact or reaction of
current or stream of working substance (steam, air. water, gases etc.) upon blades
of a wheel. It converts the potential or kinetic energy of the working substance into
mechanical power by virtue of dynamic action of working substance. When the
working substance is steam it is caned the steam turbine.
STEAM TURBINE
9. Figure: 6.2 Cross Sectional Arrangement of 500 MW Three Cylinder
Steam Turbine
10. TURBINE TYPES:
Basically there are two broad classifications of steam turbines.
IMPULSE TURBINE:
In impulse turbine, the steam is expanded (i.e. pressure is
reduced) in fixed nozzles. The high velocity steam issuing from
the nozzles dose work on the moving blades which causes the
shaft to rotate. The essential feature of an impulse turbine is that
all the pressure drops occur in these nozzles only, and there is
no pressure drop over the moving blades.
11. IMPULSE-REACTION:
In this type, pressure is reduced in both fixed and moving blades. Both fixed and
moving blades act like nozzles and are of same shape. Work is done by the impulse
effect due to the reversal of direction of the high velocity steam plus a reaction effect
due to the expansion of steam through the moving blades. This turbine is commonly
called a reaction turbine.
ENERGY LOSSES IN STEAM TURBINES:
A. INTERNAL LOSSES:
Losses directly connected with the steam conditions while in are flow through the
turbine is called internal losses. They may be further classified as
1. Losses in regulating valves.
2. Losses in nozzles (guide blades).
3. Losses in moving blades.
a. Losses due to trailing edge wake.
b. Impingent losses.
c. Losses due to leakage of steam through the angular space.
Frictional losses.
12. In electricity generation, an electric generator is a device that converts mechanical
energy to electrical energy. A generator forces electrons in the windings to flow through
the external electrical circuit. Generators produce almost an of the electricity used by
people. They supply the electrical power that runs machines in factories, provide
lighting and operate appliances at home. There are two types of generators —
alternating current (AC) generators and direct current (DC) generators. The source of
the mechanical energy may be a reciprocating or turbine steam engine, water falling on
a turbine, wind turbine or any other source of mechanical energy.
GENERATOR
INTRODUCTION
13. CONDENSER AND COOLING TOWERS
INTRODUCTION
Exhaust steam from the LP turbine enters into the condenser, where it
condenses into water by exchanging its heat energy into the cooling water. Cold
water from the river, water from the cooling tower is circulated through the tubes in
the condenser and as the steam in the condenser passes around them it is rapidly
condensed into water. Because the water has a much smaller comparative volume
than steam, a vacuum is created in the condenser. This allows the steam to reduce
down in pressure below that of normal atmosphere and more energy can be utilized.
Types Steam Condenser
The steam condenser is one of the essential components of all modern steam
power plants.
Steam condenser are of two types:
1. Surface condenser. 2. Jet condensers
14. COOLING TOWERS
Cooling towers are heat removal devices used to transfer waste heat to the
atmosphere. Cooling towers may either use the evaporation of water to remove process
heat and cool the working fluid to near the wet bulb air temperature, in the case of closed
circuit dry cooling towers. rely solely on air to cool the working fluid to near the dry-
bulb air temperature
15. The efficient working of a thermal power plant and generation of electricity in it. It is a
complex structure involving a number of stages working simultaneously for the
production of electricity.
The most important and the necessary pans of the thermal plant are
boiler, turbine. condenser and generator. The efficiency of a thermal plant depends
upon the effective working of these pans.
Thus, I conclude that the working of a thermal power plant does not entirely rely upon
the boiler and generator but; the co-ordination of various systems together get the
efficient generation.
CONCLUSION