The natural gas combustion (gas) turbines being utilized in many of today’s natural-gas-fueled power plants are complex machines, made of three main sections:

  • The compressor, which draws air into the engine, pressurizes it, and feeds it to the combustion chamber at high speed.
  • The combustion system, typically made up of a ring of fuel injectors that inject a steady stream of fuel into combustion chambers where it mixes with the air. The mixture is burned at temperatures of more than 2000 degrees F. The combustion produces a high temperature, high pressure gas stream that enters and expands through the turbine section.
  • The turbine is an intricate array of blades. As hot combustion gas expands through the turbine, it spins the rotating blades. The rotating blades perform a dual function: they drive the compressor to draw more pressurized air into the combustion section, and they spin a generator to produce electricity.

Gas turbines such as General Electric Frame 7 series engines are characterized by lower pressure ratios and generally are physically larger than Aeroderivative engines are derived from jet engines. Pressure ratio is the ratio of the compressor discharge pressure and the inlet air pressure. These larger frame turbines have higher power outputs, they have the ability to produce larger amounts of emissions, and must be designed to achieve low emissions of pollutants, such as NOx.

Fast Fact: The GE 7F.05 gas turbine generates 225 MW, equivalent to 644,000 horsepower, or the power of 644 Formula One cars. (https://www.ge.com/power/resources/knowledge-base/what-is-a-gas-turbine)

One key to a turbine’s fuel-to-power efficiency is the temperature at which it operates. Higher temperatures generally mean higher efficiencies, which in turn, can lead to more economical operation. Gas flowing through a typical power plant turbine can be as hot as 2300 degrees F, but some of the critical metals in the turbine can withstand temperatures only as hot as 1500 to 1700 degrees F. Therefore, air from the compressor might be used for cooling key turbine components, reducing ultimate thermal efficiency. Pinnacle Parts and Service Corporation can supply crucial temperature management and ignition parts to keep your plants turbines performing.