Closed Cycle Gas Turbine : Components, Working and Advantages
To overcome the drawbacks of an open cycle gas turbine method, a closed-cycle gas turbine approach is used. The primary disadvantage of an open cycle is turbine blade corrosion and erosion. This problem can be solved by using a working medium of superior quality, such as air, helium, argon, hydrogen, or neon, which doesn’t mix with the fuel in the combustion chamber. Another benefit of using a closed cycle system is that heat from exhaust gases is rejected in re-coolers, re-heaters, or heat exchangers. An overview of this turbine’s operation, benefits, and drawbacks are covered in this article.
What is a Closed-cycle Gas Turbine?
A gas turbine that overcomes the shortcomings of the open cycle gas turbine is known as a closed-cycle gas turbine. Using a compressor, heat chamber, gas turbine, and cooling chamber, the air is continuously circulated inside the gas turbine in this type of turbine. This type will have constant pressure, temperature, and air velocity ratios. It runs through a thermodynamic cycle, which involves continuously circulating and using working fluid without letting it out of the system.
Components of Closed Cycle Gas Turbine:
The isentropic process, which is adiabatic and reversible, will be carried out in the compressors. Throughout this process, no heat will be transferred.The combustion chamber or burner
Air enters the burner or A. Combustion chamber after going through the compressor. This burner will operate under constant pressure. Although the temperature and volume will rise along with the heat, the pressure will remain constant.
The air will expand and the turbine will rotate as soon as the hot air from the combustion chambers reaches the turbine and makes contact with its blade. The air will expand in the turbines in an asynchronous manner. A shaft connects the turbine to the turbine. The shaft for the compressor and the turbine is the same. The compressor receives power from the turbine as it rotates, assisting the compressor’s rotation. A few tributaries receive power from the turbine as well. A coupling connects the generator and the turbines. The generator will generate electricity using the work done by the turbine as it rotates.
Cooler or pre-cooler
The air is sent to the cooler after it has operated in the turbine. To bring the air back to its original or starting condition, the cooler will cool it. Under constant pressure, the cooler’s cooling process will be carried out.
Closed Cycle Gas Turbine Working Principle
The Brayton cycle or Joule’s cycle serves as the foundation for the closed-cycle gas turbine. This type of gas turbine employs an isotropic compressor to compress the gas, and the resulting compressed gas then enters the heating chamber. In this turbine, the rotor type compressor is preferred.
The compressed air is heated externally before being passed over the turbine blades. The gas expands as it passes over the turbine blades, is allowed to enter the cooling chamber, where it cools down. Utilizing the circulation of water under constant pressure, the gas is cooled to its initial temperature.
- The process is repeated as the gas is fed into the compressor once more.
- The same gas is repeatedly circulated in this turbine.
- If something other than air is used as the working fluid or medium in the turbine, the system would become more complex and more expensive.
- This could cause issues and is challenging to fix.
Advantages of Closed Cycle Gas Turbine:
The benefits of closed-cycle gas turbines are
- In a closed-cycle gas turbine, contaminated gases cause the turbine blades to erode, and dusting results in compressor blade fouling.
- As a result, the turbine and compressor have a longer lifespan.
- In contrast to an open cycle gas turbine, there is no atmospheric back pressure on the turbine exhaust in a closed cycle.
- There is no requirement to filter the air entering the compressor in a closed-cycle gas turbine.
- By widening the internal pressure range, high working fluid densities can be preserved.
- Compressors and turbines are therefore small relative to their rated output.
- Direct heating is accomplished in a closed-cycle gas turbine, allowing for the use of lower oil or solid fuel.
- These fuels are incredibly inexpensive.
- As a result, the procedure is more cost-effective.
- It produces a lot and is very effective.
- Low maintenance costs.
Turbine control systems
Turbine control systems monitor excessive fuel emissions, fuel control, and vibration monitoring. IS200STCIH6A, IS220PAICH1B, and IS220PAICH2B, are examples of GE parts.
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