The gas turbine power plant is also known as the combustion turbine power plant. The gas turbine is a type of continuous combustion, internal combustion engine.
There are three main components in a gas turbine, they are
A rotary gas compressor upstream;
A turbine downstream on the same axis and
A combustion chamber or area called a combustor.
Applications:
Gas turbine plants are used as reserve plants for hydroelectric power plants.
Gas turbine power plants can be used as maximum load plants and standby plants for smaller power units.
Gas turbines are used in aircraft and ships. Plants powered by pulverized fuel are used in a locomotive.
Advantage:
The economy of gas turbine power generation is proving to be more attractive, due to the low cost of capital and the high reliability and flexibility in the operation.
Fast start-up and the ability to use a wide variety of fuels, from natural gas to waste oil or coal dust, are other prominent features of gas turbine power plants. Significant progress has been made in three directions, namely, increasing the capacity of gas turbine units (50-100 mW), increasing their efficiency and reducing the cost of capital. The main application of the gas turbine plant is to supply the maximum load. However, at present, gas turbine plants are universally used as maximum load, base lead and reserve plants.
It is smaller in size and weight compared to an equivalent steam power plant. For smaller capacities, the size of the gas turbine power plant is significantly larger than a high speed diesel engine plant, but for larger capacities, it is smaller in size than a comparable diesel engine plant. If size and weight are the main consideration, as in ships, aircraft engines and locomotives, gas turbines are more suitable.
The initial cost and operating cost of the gas turbine plant are lower than an equivalent steam power plant. The plant requires less water compared to a condensation steam plant.
The plant can be started quickly and loaded in a very short time.
There are no reserve losses in the power plant of the gas turbine, while in the steam power plant these losses occur because the boiler remains in operation even when the turbine is not supplying any load.
The maintenance cost of the gas turbine power plant is low and easier to maintain.
The lubrication of the plant is easy. In the gas turbine plant, lubrication is mainly needed in compressors, main turbine bearings and auxiliary equipment bearings.
The plant does not require foundations and massive construction.
There is a significant simplification of the plant on a steam plant due to the absence of boilers with its feedwater evaporator and its condensation system.
Disadvantages:
The significant part of the work developed by the turbine is used to derive the compressor. Therefore, the network output of the plant is low.
The temperature of the combustion products becomes too high, so the service conditions become complicated even at moderate pressures.