NTPC REPORT (DOC)

							                                       2011
SUMMER TRAINING REPORT




                           AKSHAY MAHAJAN
                             EEE - 00711507809
      Bharati Vidyapeeth's College of Engineering
                                       New Delhi
                             CLASSIFICATION
By fuel

 Nuclear power plants use a nuclear reactor's heat to operate a steam turbine
generator.
  Fossil fuelled power plants may also use a steam turbine generator or in the case
of natural gas fired plants may use a combustion turbine.
  Geothermal power plants use steam extracted from hot underground rocks.
  Renewable energy plants may be fuelled by waste from sugar cane, municipal
solid waste, land fill methane, or other forms of bio mass.
  In integrated steel mills, blast furnace exhaust gas is a low-cost, although low-
energy density, fuel.
 Waste heat from industrial processes is occasionally consent rated enough to use
for power generation, usually in a steam boiler and turbine.


By prime mover

 Steam turbine plants use the dynamic pressure generated by expanding steam to
turn the blades of a turbine. Almost all large non-hydro plants use this system.

 Gas turbine plants use the dynamic pressure from flowing gases to directly
operate the turbine. Natural-gas fuelled turbine plants can start rap idly and so are
used to supply "peak" energy during periods of high demand, though at higher cost
than base-loaded plants. These may be comparatively small units, and sometimes
completely unmanned, being remotely operated. This type was pioneered by the
UK, Prince town being t he world's first, commissioned in 1959.

 Combined cycle plants have both a gas turbine fired by natural gas, and a steam
boiler and steam turbine which use the exhaust gas from the gas turbine to pro duce
electricity. This greatly increases the overall efficiency of the plant, and many new
base load power plants are combined cycle plants fired by natural gas.

 Internal combustion Reciprocating engines are used to provide power for isolated
communities and are frequently used for small cogeneration plants. Hospitals,
office buildings, industrial plants, and other critical facilities also use them to
provide backup power in case of a power outage. These are usually fuelled by
diesel oil, heavy oil, natural gas and landfill gas.

  Micro turbines, Sterling engine and internal combustion reciprocating engines are
low cost solutions for using opportunity fuels, such as landfill gas, digester gas
from water treatment plants and waste gas from oil production.
         Process of a Thermal Power Plant
Detailed process of power generation in a thermal power plant:

 1) Water intake: Firstly, water is taken into the boiler through a water source. If
water is available in a plenty in the region, then the source is an open pond o r river.
If water is scarce, then it is recycled and the same water is used over and over
Again.

2) Boiler heating: The boiler is heated wit h the help of oil, coal or natural gas. A
furnace is used to heat the fuel and supply the heat produced to the boiler. The
increase in temperature helps in t he transformation of water into steam.

3) Steam Turbine: The steam generated in the boiler is sent through a steam
turbine. The turbine has blades t hat rotate when high velocity steam flows across
them. This rotation of turbine blades is used to generate electricity.

4) Generator: A generator is connected to the steam turbine. When the turbine
rotates, the generator produces electricity which is then passed on to t he power
distribution n systems.

5) Special mountings: There is some other equipment like the economizer and air
pre-heater.
An economizer uses the heat from the exhaust gases to heat the feed water. An air
pre-heater heats the air sent into the combustion chamber to improve the efficiency
of the combustion process.

6) Ash collection system: There is a separate residue and ash collection system in
place to collect all the waste materials from the combustion process and to prevent
them from escaping into the atmosphere.
Apart from this, there are various other monitoring systems and instruments in
place to keep track of the functioning o f all the devices. This prevents any hazards
from taking place in t he plant.
                                         BOILER




                       External View of an Industrial Boiler at BTPS, New Delhi

The steam/vapor is passed through a series of steam and water separators and then
dryers inside the steam drum. The steam separators and dryers remove the water
drop lets from the steam and the cycle through the water walls is repeated. This
process is known as natural circulation. The boiler furnace auxiliary equipment
includes coal feed nozzles and igniter guns, soot blowers, water lancing and
observation ports (in the furnace walls) for observation of the furnace interior.
Furnace explosions due to any accumulation of combustible gases after a trip out
are avoided by flushing out such gases from the combustion zone before igniting
the coal. The steam drum (as well as the superheated coils and headers) have air
vents and drains needed for initial start-up. The steam drum has an internal device
that removes moisture from t he wet steam entering the drum from t he steam
generating tubes. The dry steam t hen flows into the superheated coils. Geothermal
plants need no boiler since they use naturally occurring steam sources. Heat
exchangers may be used where the geothermal steam is very corrosive o r contains
excessive suspended so lids. Nuclear plants also boil water to raise steam, either
 directly passing t he working steam through the reactor or else using an
intermediate heat exchanger.
                      Fuel Preparation System
In coal-fired power stations, the raw feed coal from the coal storage area is first
crushed into small pieces and then conveyed to the coal feed hoppers at the boilers.
The coal is next pulverized into a very fine powder. The pulverizes may be ball
mills, rotating drum grinders, or other types of grinders. Some power stations burn
fuel oil rather than coal. The oil must kept warm (above its pour point) in the fuel
oil storage tanks to prevent the oil from congealing and becoming unpumpable.
The oil is usually heated to about 100°C before being pumped thro ugh the furnace
fuel oil spray nozzles.




                     Boiler Side of the Badarpur Thermal Power Station, New Delhi