A gas turbine is also known as combustion turbine. It is an internal type of combustion engine. In the downstream turbine upstream rotating compressor is coupled in-between combustion chamber also.
Gas Turbine power plant:
It is defined as the principal prime mover which is of the turbine type and the medium of working is permanent gas”.
Components present in the gas turbine power plant:
- Combustion chamber
- Gas turbine
- Reheating unit
In most of the cases centrifugal and axial turbines are used in the gas turbine power plants. Two compressors are used in the gas turbine power plant. In that one of them is low pressure compressor and the other one is high pressure compressor. Through the filer the atmospheric air must be drawn into the compressor by using the low pressure compressor. The developed power must be used to run the compressor. It uses nearly 66% of the power source. With the help of the intercooler low pressure air, and is moved into the high pressure compressor. Then immediately the high pressure air must be moves in to the regenerator.
The main aim of the intercooler is to reduce the compressor work and it is to be placed between the low pressure and high pressure compressors. Where the pressure ratio must be high then intercoolers are used. The energy required to compress the air must be proportional to the inlet air pressure. The compressed air cooling in the intercooler is complete by water.Advertisement:
When the air is entering to the regenerator then preheating is doen to reduce the fuel consumption in the combustion chamber, where the efficiency needs to be increased. This is done by heat of hot exhaust gases coming out of the turbine.
From the regenerator hot air must be allowed to flow into the combustion chamber. The fuel like natural gas, coal and kerosene are inserted into the combustion chamber. So the high temperature and high pressure products of combustion must be passes through the turbine.
Working of gas turbine power plant:
From the atmosphere the air must be drawn into the low presser compressor with the help of the air filter and then it must be compressed.
The compressed low pressure air must come out into the compressor which contains high pressure through the intercooler. So the heat compressed air must be removed. Then the compressed air which consists of high presser must be allowed to go into the combustion chamber with the help of the regenerator. The fuel must be added to the compressor air with the help of the combustion chamber, and then the fuel combustion needs to takes place. So the products obtained from the combustion must be allowed into the high pressure turbine. The exhaust present the high pressure turbine must be enters in to another combustion chamber. In which the additional fuel must be added then it moves through the low pressure turbine. In the low pressure turbine after completion of expansion the exhaust must be used as heat the sir coming out with high pressure. Then it moves to the combustion chamber followed by the regenerator. Then the exhaust must be released in to the atmosphere.
Advantage of gas turbine power plant:
- In gas turbine power plant natural gas is suitable as the fuel. Depends up the available of the natural gas turbine must be installed.
- Gas turbine power plants can effort carefully for small organization hours.
- Loading of fuel needs less capacity and handling is stress-free.
- Gas turbine power plant is minor and close in size when compared with the steam power plants
- It can be started fast and can be place on load in an identical small interval time
- The maintenance cost is less
- It is simple in construction compare to the remaining power plants
- In case of the steam power plants there is no requirement for boiler, condenser
- The gas turbine can function at high speed meanwhile there is no reciprocating part
- Cheaper fuel such as paraffin, kerosene, powdered coal and benzene can be used
- Gas turbine power plants can be used in water shortage areas
- Less pollution is noticed
- A smaller amount of water is necessary for the method
Disadvantage of gas turbine power plant:
- To effort the compressor 66% of the developed source is recycled
- The gas turbine unit has a small thermal efficiency
- The running speed of the gas turbine is in the range from 40k to 100k rpm
- The working temperature is as great as 2000 C, for this reason different alloys and metals are used for the several components of the turbine
- Special cooling techniques are necessary for cooling the turbine blades
- It is hard to start a gas turbine as associated to a diesel engine in a diesel power plant
- The life span of a gas turbine plant is up to 10 years, after which its efficiency declines to less than 10 percent
Application of gas turbine power plant:
- To drive generators and supply loads in steam, diesel or hydro plants
- To work with conventional steam boilers as combination plants
- Thermal process industries
- Petro chemical industries
- Power generation in aircraft and ships for their propulsion.
- They are not suitable for cars because of their high speeds
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