Top 5 Types of Gas Turbine Filters Types and its overview
Proper air filtering is crucial for gas turbine performance and dependability. Fuel expenses account for about 80% of the total cost of power throughout its life. Small efficiency improvements can result in enormous savings.
Using fuel prices hovering around $16.00/mmBTU and even higher in certain worldwide areas, operational savings can be realized by optimizing compressor performance with High Efficiency (HEPA) air filters. Operators can expect significant cost savings from a cleaner engine, as measured by fewer inspections, fewer shutdowns, and increased availability.
HEPA filtration can retain peak GT efficiency throughout the filter’s life. The purpose of this paper is to examine the selection criteria for choosing the optimal air filtering system to increase gas turbine availability and reduce operating costs.
Overview of Air Filtration and Conditioning
Aeroderivative gas turbine ventilation and combustion air filter systems are intended to protect the gas turbine, generator, and equipment compartments from dirt, pollution, and foreign objects carried by air.
Additionally, there are a variety of intake conditioning solutions available to optimize gas turbine performance.GE Distributed Power gas turbines include a three-section intake air filter that is mounted immediately above the turbine enclosure, saving space and enabling compact, low- pressure-loss ducting to the turbine inlet.
1. Weather Hoods and Drift Eliminators
The air entering the filter house travels via (optional) weather hoods, drift eliminators, and input screens before entering the filter house.
The Weather hoods shield filters from the elements such as rain, snow, and sunlight.
Weather hoods are attached to the left and right coil assemblies intake sides (for dual inlet systems).
Weather hoods keep rain and snow out of the intake filter house by pulling inlet air upward at a slower rate than rain and snowfall. For snowy or tropical settings, snow hoods and tropical rain hoods are offered. Additionally, inertial moisture separators (vane-type separators) are provided to keep heavy rain and fog mist out of the filter house.
2. Multi-Stage Filtration
A two-stage filtration system is available, consisting of a guard filter located upstream of the chiller coils and a set of composite canister “barrier” or panel-type filters downstream of the coils. The guard filters (alternatively referred to as pre-filters) keep the chiller coils clean for maximum heat transfer efficiency and provide supplementary filtration to extend the life of the fine composite filters.
Fine filter elements are attached to the inlet plenum’s filter face and extend into the clean air plenum. The elements feature a wide surface area, a high capacity for dirt retention, and a minimum pressure drop. The air is filtered finely and enters the clean air plenum. This fabricated structure serves as the inlet filter assembly’s central section, separating ventilation and combustion air.
3. Cooling and heating of the inlet
To optimize gas turbine performance on hot days, air cooling options include evaporative coolers or optional intake air chiller coils. Coils, on the other hand, can be utilized for anti- icing and/or efficiency optimization throughout partial power operations.
The evaporative cooling system utilizes the process of evaporation to reduce the temperature of the incoming air. Water is pushed to a header, which distributes it through corrugated layers of a fibrous substance called media blocks. Heat is transferred from the air to the water through channels where air meets falling water. This will cause some of the water to vaporize.
4. Filter for Pulse
Pulse filters can and have been effectively utilized in very dusty settings such as steel mills, cement factories, the Middle East, and regions prone to sand or dust storms, even at high humidity levels.
The pulse controller can be set to pulse according to the requirements of the loading (e.g., based on filter pressure drop, ambient relative humidity, hourly, daily, or even continuously). Pulse filters are also used when operating a turbine in an environment with a high concentration of snow or ice crystals.
Although a static filter can be used in these environments if an upstream conditioning system (e.g., heating coils, bleed air, or other hot air conditioning) is properly designed, pulse systems are the most reliable at preventing filters from plugging due to cold weather moisture.
Another advantage of pulse filter systems, particularly for peak loading turbines, is that the filters can be pulsed while the unit is idle, maximizing the effectiveness of the pulse cleaning and preparing the filters for the next start-up.
5. Filter Static
Static filters can be equipped with low-cost pre-filters that can be replaced and/or cleaned to prolong the life of the barrier elements. However, specialized pre-filters can become a maintenance item, increasing project costs over time.
For instance, in areas with a high hydrocarbon loading or areas with cement dust and frequent periods of high humidity, pleated composite type pre-filters are frequently required rather than the more common fibrous type to avoid a short barrier filter life.
These pre-filters are less expensive but must be replaced (or possibly removed and cleaned) on a fairly regular basis.
Gas turbine top performance necessitates the use of proper filtration. The ideal filters and configuration are determined by operation and environmental conditions. Inadequate filtration will reduce turbine performance by eroding blades, fouling, clogging cooling passages, and corroding.
These and other considerations should be reviewed with your turbine or filter maker. Cost-benefit analysis can be used to account for the filter purchase price, fuel price, power selling price, maintenance, inspections, wash cycles, power degradation, heat rate rise, pressure loss, labor expenses, and downtime in various operating situations.