GAS%20TURBINE%20POWER%20PLANTS

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GAS TURBINE POWER PLANTS
BY ABHISHIEK PAWAR - 0815002 ANIL NAIR -
0815012 ANIRUDDHA SAWANT - 0815013 ANJALI DESAI
- 0815014
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INTRODUCTION

• A generating station which employs gas turbine as
  the prime mover for the generation of electrical
  energy is known as a gas turbine power plant.
• In a gas turnine power plant,air is used as the
  working fluid.The air is compressed by the
  compressor is lead to the combustion chamber
  where heat is added to air,thus raising its
  temperature.Heat is added to the compressed air
  either by burning fuel in the chamber or by the
  use of air heaters.The hot and high pressure air
  from the combustion chamber is then passed to the
  gas turbine where it expands and does the
  mechanical work.The gas turbine drives the
  alternator which converts the mechanical energy
  into electrical energy.

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SIMPLE GAS TURBINE CYCLE
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AIR STANDARD BRAYTON CYCLE
1 - 2    Isentropic compression2 - 3    Constant
pressure heat addition3 - 4    Isentropic
expansion4 - 1    Constant pressure heat removal
P-V Diagram
T-S Diagram
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SIMPLE GAS TURBINE LAYOUT
FRONT VIEW
TOP VIEW
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FUELS

• One further advantage of gas turbines is their
  fuel flexibility. They can be adapted to use
  almost any flammable gas or light distillate
  petroleum products such as gasoline (petrol),
  diesel and kerosene (paraffin) which happen to be
  available locally, though natural gas is the most
  commonly used fuel. Crude and other heavy oils
  and can also be used to fuel gas turbines if they
  are first heated to reduce their viscosity to a
  level suitable for burning in the turbine
  combustion chambers.

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ADVANTAGES

• It is simple in design as compared to steam power
  station since no boilers and their auxiliaries
  are required
• it is much smaller in size as compared to steam
  power station of same capacity.This is expected
  since gas turbine power plant doesnot require
  boiler,feed water arrangements etc
• The initial and operating costs are much lower
  than that of equivalent steam power station
• It requires comparatively less water as no
  condenser is used
• The maintenance charges are quite small
• Gas turbines are much simpler in construction and
  operation than steam turbines
• It can be started quickly from cold conditions
• There are no standby losses.However,in a steam
  power station,these losses occur because boiler
  is kept in operation even when the steam turbine
  is supplying no load

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DISADVANTAGES

• There is a problem for starting the unit.It is
  because before starting the turbine,the
  compressor has to be operated for which power is
  required from some external source.However once
  the unit starts,the external power is not needed
  as the turbine itself supplies necessary power to
  the compressor.
• Since a greater part of the power developed by
  the turbine is used in driving the compressor,the
  net output is low
• The overall efficiency of such plants is
  low(about 20) because of the exhaust gases from
  the turbine contain sufficient heat
• The temperature of combustion chamber is quite
  high(3000 deg.F)so that its life is comparatively
  reduced

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GAS POWER PLANTS IN INDIA
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THE MAIN COMPONENTS OF A GAS TURBINE POWER PLANT

• COMPRESSOR
• TURBINE
• HEAT EXCHANGER
• INTERCOOLER

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COMPRESSOR

• The compressor sucks in air form the atmosphere
  and compresses it to pressures in the range of 15
  to 20 bar. The compressor consists of a number of
  rows of blades mounted on a shaft. This is
  something like a series of fans placed one after
  the other. The pressurized air from the first row
  is further pressurized in the second row and so
  on. Stationary vanes between each of the blade
  rows guide the air flow from one section to the
  next section. The shaft is connected and rotates
  along with the main gas turbine.

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TURBINE

• The turbine does the main work of energy
  conversion. The turbine portion also consists of
  rows of blades fixed to the shaft. Stationary
  guide vanes direct the gases to the next set of
  blades. The kinetic energy of the hot gases
  impacting on the blades rotates the blades and
  the shaft. The blades and vanes are made of
  special alloys and designs that can withstand the
  very high temperature gas. The exhaust gases then
  exit to exhaust system through the diffuser. The
  gas temperature leaving the Turbine is in the
  range of 500 to 550 C.

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HEAT EXCHANGER

• Two kinds of heat exchangers are used
• a) Recuperators and b)Regenerators
• In recuperative type, the air and hot gases are
  made to flow in counter direction as the effect
  of counter-flow gives high average temperature
  difference causing the higher heat flow.

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HEAT EXCHANGER

• The regenerator type heat exchanger consists of a
  heat conducting member which is exposed
  alternately to the hot exhaust gases and the
  cooler compressed air. It absorbs heat from hot
  gases and gives it up when exposed to the air.
  The heat capacity member is made of a metallic
  mesh or matrix which is rotated slowly (40-60
  rpm) and continuously exposed to hot and cold air.

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(iii)Combustion Chamber The air at high pressure
from the compressor is led to the combustion
chamber via the regenerator.In the combustion
chamber,heat is added to the air by burning oil .
The oil is injected through the burner into the
chamber at high pressure ensure atomization of
oil and its through mixing with air . The result
is that the chamber attains a very high
temperature(about 3000F).The combustion gases are
suitably cooled to 1300F to 1500F then delivered
to gas turbine.
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INTERCOOLER

• An intercooler is generally used in a gas turbine
  power plant when the pressure ratio used is
  sufficiently large and the compression is
  completed with two or more stages
• A cross flow type intercooler is generally
  preferred for effective heat transfer

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URAN GAS TURBINE POWER PLANT
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• It is the first gas-run electricity plant in asia
  
• This power station has got first air cooled
  condensor in asia.
• It consists of nine units overall
• UNIT 1 was commisioned in February 1982
• The plant can be brought to full speed in 3
  minutes and at full load in 8 minutes

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Total Capacity of Station.852 MW GT        
3 x 60 MW                    GT         4 x
108 MW                    WHRP  2 x 120 MW
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• The plant is located close to ONGC Uran terminal
  where the gas separation is done
• A 220 kV sub-station has been established which
  connects the station to the state 220 kV network
• A pipeline of 30 cm diameter and 6 km long from
  ONGC terminal to gas turbine station is completed
  in 1982 to supply the gas separated at ONGC
  terminal

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REFERENCES
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THANK YOU