Gas Turbines: Air Filtration Importance

The Importance of Gas Turbine Inlet Air Filtration

Gas turbines require a considerable amount of air for operation which increases the risk of airborne contaminants being introduced into the turbines. This can affect the function of turbine blades and thus reduce the optimum operation of the engine. To minimize this risk there is an essential need for proper inlet filtration. Adequate G.T. inlet air filtration helps prevent engine performance from being affected due to damaged caused to turbine blades.

Improper inlet air filtration in the gas turbine can lead to critical consequences such as...

Foregine Object Damage (FOD) can cause compressor damage and other parts in the path of the air flow can also be damaged. Adequate G.T. inlet filtration can prevent foreign objects from entering the compressor protecting vital components.

Blade Erosion can cause stress concentrations on the blades which, in turn, decreases power output and can eventually lead to system fatigue, high cycle failures and reduced engine efficiency. Particles that enter inadequately filtered airflow react on the blade surface which can cause erosion. The hot gas parts are especially affected by erosion. These particles attach to compressor blades and cut away small quantities of metal. One of the most common causes of erosion is sand. The resulting reduction in cross sectional area of blade leads to severe damages in turbines, since local stresses are increased. An effective and maintained gas turbine inlet air filtration system helps to avoid entrance of these particles.

Fouling which is the accumulation of sticky contaminants such as oil vapors or unburned hydrocarbons etc., on the airfoils of a blade, disrupts rotating balance, leads to clearance changes, obstructs flow paths and reduces smoothness of stationary and rotating blade surfaces. Gas turbine inlet air filters play a vital role in avoiding fouling.

Corrosion is the deposition of contaminant particles that alters blade surfaces through chemical reactions. Low temperature--wet--corrosion is an electrolytic process taking place in humid settings, while high temperature corrosion is caused when alkali metals are combined with sulfur. Corrosion will badly affect the cross sectional properties, blades, nozzles, combustor liners and nozzles. Adequate G.T. inlet filtration will prevent corrosion by keeping particles from entering.

Cooling Passage Plugging is the blockage of the vane cooling passages. Clean flow is required within passages to the combustion liner, buckets and nozzles to maintain optimum metal temperatures. Contaminants and particles reduce this cooling efficiency leading to an over-heated engine and engine failure. GT Inlet air filtration is the solution.

Particle Fusion Tiny particles probably have negligible impacts on a gas turbine; however, if these ingested particles bear a lower fusion temperature than the G.T.’s operating temperature, the particles will melt and stick to turbine’s internal surfaces; a condition called particle fusion. The particle fusion blocks cooling passages and affects the turbine blade profile, leading to extreme thermal failure. Adequate gas turbine inlet air filtration helps to avoid particle fusion.

What is the solution to avoid these damages?

High efficiency G.T. Inlet Air Filters are the ideal solution to:

  • Hinder FODs by preventing the large particle entering the compressor
  • Block hard particles like sand to enter the air flow passages to prevent erosion
  • Reduce the risk of fouling through submicron particles filtration
  • Avoid cooling passages plugging
  • Prevent particle fusion
  • Obstruct corrosion