The Pros and Cons of Gas Turbine Power Stations with Schematic Diagram: Is This the Best Energy Solution?
Gas Turbine Power Station
A generating station which employs a turbine because the first cause for the generation of electricity is as referred to as a turbine power station. In a turbine power station, the air is employed because of the working fluid. The compressor compresses the air and is led to the combustion chamber where heat is added to the air, thus raising its temperature.
Generally, Heat is added to the compressed gas either by burning fuel within the chamber or by the utilization of air heaters. The hot and high-pressure air from the combustion chamber passed to the turbine where it expands and does the mechanical work.
The turbine drives the alternator which converts energy into electricity. It may mention here that the compressor, turbine, and alternator are mounted on an equivalent shaft in order that a neighborhood of the mechanical power of the turbine can utilize for the operation of the compressor.
Gas turbine power plants are used as standby plants for hydro-electric stations, as a starting plant for driving auxiliaries in power plants, etc.
Pros of Gas Turbine Power Plant
(i) It's simple in design as compared to the steam power plant since no boilers and their auxiliaries are required.
(ii) It's much smaller in size as compared to the steam power plant of an equivalent capacity. We expected that since the turbine power station doesn't require a boiler, feedwater arrangement, etc.
(iii) The initial and operating costs are much less than those of the equivalent steam power plant.
(iv) It requires comparatively less water as no condenser is used.
(v) The upkeep charges are quite small.
(vi) Gas turbines are much simpler in construction and operation than steam turbines.
(vii) It can start quickly from cold conditions.
(viii) There are not any standby losses. However, in a steam power plant, these losses occur because the boiler is kept operational even when the turbine is supplying no load.
Cons of Gas Turbine Power Plant
(i) There's a drag with starting the unit. It's because before starting the turbine, the compressor has got to operate that power is required from some external source.
However, once the unit starts, the external power isn't needed because the turbine itself supplies the required power to the compressor.
(ii) Since a greater part of the facility is developed by the turbine and it uses for driving the compressor, internet output is low.
(iii) The general efficiency of such plants is low (about 20%) because the exhaust gases from the turbine contain sufficient heat.
(iv) The temperature of the combustion chamber is sort of high (3000°F) in order that its life is comparatively reduced
Schematic Arrangement of the turbine power station
The main components of the plant are:
(i) Compressor
(ii) Regenerator
(iii) Combustion chamber
(iv) Turbine
(v) Alternator
(vi) Starter
(i) Compressor:
The compressor utilized in the plant is usually of rotatory type. The compressor drew the air at air pressure via the filter which removes the dust from the air. The rotatory blades of the compressor push the air between stationary blades to boost its pressure. Thus air at high is out there at the output of the compressor.
(ii) Regenerator:
A regenerator may be a device that recovers heat from the exhaust gases of the turbine. The exhaust is skilled in the regenerator before wasting the atmosphere.
A regenerator consists of a nest of tubes contained in a shell. The compressed gas from the compressor passes through the tubes on its thanks to the combustion chamber.
In this way, compressed gas is heated by the recent exhaust gases.
(iii) Combustion chamber:
The air at high from the compressor is led to the combustion chamber via the regenerator. within the combustion chamber, heat is added to the air by burning oil.
The oil-injected through the burner into the chamber at high to make sure the atomization of oil and its thorough mixing with air.
The result's that the chamber attains real heat (about 3000°F). The combustion gases are suitably cooled to 1300°F to 1500°F then delivered to the turbine.
(iv) Gas turbine:
The products of combustion consisting of a mix of gases at heat and pressure are passed to the turbine.
These gases en passant over the turbine blades expand and thus do the mechanical work. The temperature of the exhaust gases from the turbine is about 900°F.
Note: Only hot pressurized air makes it possible to convert heat into mechanical work. Heating air at air pressure generally doesn't make it permissible to convert heat into mechanical work.
(v) Alternator:
The turbine is coupled to the alternator. The alternator converts the energy of the turbine into electricity. The output from the alternator is given to the bus-bars through the transformer, circuit breakers, and isolators.
(vi) Starting motor:
Before starting the turbine, the compressor has got to be started. For this purpose, an electrical motor is mounted on an equivalent shaft as that of the turbine.
The motor is energized by the batteries. Once the unit starts, a neighborhood of the mechanical power of the turbine drives the compressor and there's no need for a motor now.
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