16-09-2014, 12:23 PM
GAS TURBINE
POWER PLANT
GAS TURBINE.pptx (Size: 2.35 MB / Downloads: 27)
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.
Air is used as the working fluid.
Air is compressed by the compressor is lead to the combustion chamber where heat is added to air.
Hot and high pressure air from the combustion chamber is then passed to the gas turbine where it is expands and does the mechanical work.
The gas turbine drives the alternator which converts the mechanical energy into electrical energy.
These plants are suitable for peak load purpose because their fuel costs are some what higher while there initial cost are low.
Simple gas turbine plant
A simple gas turbine plant consist of a compressor, combustion chamber or combustor and turbine.
Besides these components there may be auxiliaries such as starting device, fuel system, the duct system, auxiliary lubrication system etc.
working
When the unit runs atmospheric air is drawn in by the compressor and it raised to starting pressure which is several time that of atmosphere.
The fuel injected into the combustor.
The temperature exhaust gases is in the range of about 475° to 550° C.
N.B.:- in the compressure a part of the air is delivered ahead of the burning fuel this is done to cool the very hot combustion products which are at temperature 1600° C to bring them down to a temperature of range 650° to 800°C.
3.Reheating
Gasses after partial expansion in the turbine may be reheated so that they can be expanded further and may produced additional work.
Reheating may in fact be taken as anb additional combustor.
Advantages
Simple in design
Smaller in size
Initial and a operating cost are much lower
Require less water
Maintenance charges quite small
Simple construction and operation
Started quickly from cold condition
Disadvantages
There is problem for starting the unit
Net output is low
Over all efficiency is low
Life is comparatively reduced
Conclusion
From the above topic I conclude that gas turbine plants possess inherent advantages of simplicity and flexity of design and installation.
From the view of point of price it has been estimated that the steam plant developing power at 17% efficiency costs equal to the gas turbine plant developing power at 34%. This being the case that gas turbine plant as a base load plant has little future