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Gas turbines power plants

Gas turbines for generating electricity are used for a long time, particularly since 1939. In present the gas turbines are the most commonly used power generating technologies. Gas turbines are a kind of combustion engine in which is burned air-fuel blend that conduct to production of hot gases which spin the turbine, the turbine then produce energy. The name of gas turbines is because of the production of hot gas during fuel combustion, and not the used fuel in the turbine. Gas turbines may use a various types of fuels, including natural gas, associated petroleum gas, shale gas, fuel oils (kerosene, diesel), and synthetic fuels. The combustion of fuel take place unceasingly in gas turbines, as compared with to reciprocating engines, where the combustion of fuel take place discontinuously.

How it works?

Usually the gas turbines are constituted of three primary sections assembled on the same shaft: compressor, combustion chamber and turbine. The compressor may be axial flow or centrifugal flow. The axial flow compressors are more widespread in power generation as they give higher performances and flow rates. The axial flow compressors are constituted of numerous rows of revolving and stationary blades through which pass the air in parallel to the rotation axis and increasingly compressed as it traverses each stage. The air acceleration through the revolving blades and dissemination by the stators amplify the pressure and contract the air volume. While the compression of the air the temperature grow even if there is no heat thrown on.

The blend of fuel and compressed air is injected through nozzles. The compressed air and fuel may be preliminary blended or the compressed air can be sent directly into the combustor. The blend of fuel and air kindles at invariable pressure and the hot gases resulted from combustion are sent through the turbine where it expands precipitously and conveys rotation to the shaft. The turbine is also composed of stages, each with a row of stationary blades to guide the expanding gases and a row of revolving blades. The shaft spinning drives the compressor to draw in and compress more air in order to maintain the combustion ongoing. The remaining power of the shaft is utilized to drive the generator, which produces electricity. About 55 – 65 % of the produced by turbine power is utilized to drive the compressor. In order to optimize the shifting of kinetic energy from combustion of gases to the revolving of the shaft, gas turbines may have several stages of compressor and turbine.

As the movement of compressor need power, the efficiency of energy conversion for an ordinary cycle gas turbine unit is commonly about 30 % and even at the most efficacious engineering it is up to 40 %. The exhaust gas still have a big amount of heat, his temperature is about 600ºC when it leaves the turbine. The plant efficiency may be reached to 55 – 60 % in the means of recovering that waste heat in order to make possible creation of more useful work in a combined cycle configuration of gas turbine power plant. At the same time there are operational limitations connected to the operating gas turbines in combined cycle mode, including more time for startup, requirements for cleaning in order to avert fires or explosions, and ramp rate to full load.

PromFin Energo provide development and construction of gas turbines power plants. On the electro-energetical market the gas turbine equipment is quite common. In gas turbine power plants of highest quality the main advantages are high susceptibility to load variations, the use of several fuels types without affecting the operation of the turbine, the practical absence of vibrations, excellent environmental performances, minimum financial expenses and time required for technical maintenance.

On the power plant that use heat exchangers is obtained heat and this process is called cogeneration. The amount of heat depends on the type and capacity of the power station. Gas turbine units produce much more heat energy than the reciprocating power station and micro turbines. The difference in the amounts of generated thermal energy is up to 50%.
The most important thing is that the hot water resulted from the process is used for heating or for alternative processes.


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