Now days, the Gas turbine is one of the most widely used technology for power generation. Brown Boveri Corporation installed the first turbine in Switzerland in 1939. The gas turbine consists of the air inlet, compressor, combustion chamber, turbine, and exhaust. We divide the turbine into two sections, i.e., a cold section and a hot section. The gas turbine is also called a combustion turbine, a continuous internal flow combustion engine. Therefore gas turbine control system is use to control the entire process.
The gas turbine is not only use for power generation but is also use for the gas compressor. The gas turbine is the primary mover for compressors. Many countries use gas turbines to compress natural gas to supply long-distance consumers like the Russian supply was to Europe. Pakistan provides natural gas to consumers, i.e. houses, industries, and powerhouses.
What is the working principle of a gas turbine?
The Gas turbines is working on the Brayton cycle of thermodynamics which explains the operation of heat engines that have air and fuel as their working fluid. The process consists of compression of air, mixing of gas with compress air, igniting the mixture, combustion occurs, and expanding gas exhaust.
How does The Gas Turbine work?
The gas turbines consists of a compressor, combustion chamber, and turbine. All three parts are connect on the same single shaft, which gives a continuous cycle. The compressor may be axial flow or a centrifugal flow type but mostly use axial flow because of efficiency and high airflow.
The centrifugal flow is use in some gas turbines to achieve the design fuel-to-air ratio, but most gas turbines uses axial flow compressors. The axial flow compressor in the gas turbine is in multistage, compressing air in a stage to get the desired compression ratio. The compressors consist of stationary and rotating blades. The rotating blades are connected to a standard shaft and stationary on the compressor’s housing. The compressor increases the pressure by compressing the air and reducing the volume of air. Due to the friction of air molecules, the compressed air temperature is also raise. Finally, the compress air is enter into the combustion chamber mix with gas, and ignition takes place to get the combustion process.
The combustion chamber consists of a multi-sparking or single plug as per design. Some turbines use multi-sparking pins to get different desire speeds. Initially, all sparking plug fires, and when the turbine gets its rate, only one flashing plug is use for ignition. At this stage, the starter system of the turbine is disengaged. The turbine speed varies by manufacturer and design. The gas turbines speed ranges from 2800 RPM to 15000 RPM.
What is the role of the gas turbine in the power plant?
The gas turbine is widely use in the power plant. The majority of installation of gas turbines in power plants is connecte with a combine cycle to get maximum efficiency from fuel. In the Combine cycle power plant, the exhaust of the gas turbines, which is about 800’C to 1000’C use to accelerate the steam turbines with the help of the boiler. The gas turbine’s exhaust is use to preheat water before it enters the boiler.
How important is the gas turbine?
The gas turbines is a prime mover for the generator. First, the gas turbines shaft is couple with a generator to give rotation to generate electricity. The speed, of course, depends upon the frequency require for the electricity. In addition, the fuel supply and ignition can control the speed of the turbine. Finally, the compressor uses the gas turbine’s approximately 50 % to 55% efficiency to get air compress in the combustion chamber, and the rest of the efficiency is use in driving the generator to produce electricity.
