Gas Turbines: Environmental Considerations

Gas Turbine Inlet Air Filters for All Environments

Did you know that clean air is as vital to a gas turbine’s reliability and efficiency as food is to a human body? Get the innovative and technologically advanced air filtration products and services for your gas turbine systems. With various brands on board from some of the world-class leaders in the industry, Advanced Filtration Concepts (AFC) offers a new and comprehensive range of gas turbine Inlet air filters for all environments and their associated conditions.

GT Inlet Air Filtration for Coastal, Marine, or Offshore Environment

Gas turbines running near or on the ocean are required to operate in coastal, marine and offshore settings.

Salt air is the primary contaminant in coastal, marine and offshore environments and leads to fouling and corrosion. In coastal environments where there is lower humidity dry and sticky liquid can form. In offshore settings, aerosol is present in liquid or particle form, while in marine environments; it’s in a liquid state. Wind speed, direction and elevation of the turbines will affect the quantity of salt present in these environments.

Apart from salt, coastal environments are also faced with land based contaminants in the air, while offshore environments witness industrial contaminants like byproducts of maintenance and exhaust fumes The submicron size of these particles and the need to eliminate excessive water, moisture and salt, require high efficiency filtration. In addition, in offshore and coastal environments, icing can be another concern. Advanced Filtration Concepts carries the required gas turbine inlet air filters for these environments, which ensure turbines continually operate at maximum output efficiency.

A gas turbine power plant is said to be in the coastal environment if:

  • It is installed nor more than 10 miles or 16 km away from the ocean
  • Its installation is on land

The distance of around 8 to 12 miles or 13 to 19 km or more from the shorelines, decreases the salt concentration in the air and brings it to natural background levels for an environment that is farther away from the ocean. Turbines that are in environments located closer to the ocean are considered “marine” and “offshore environments."

A gas turbine power plant is said to be in an offshore environment if:

  • It is located at 100 ft or 30.5m off (minimum) the ocean.

A gas turbine power plant is said to be in the marine environment if:

  • It is located less than 100 ft or 30.5m from the ocean.

GT Inlet Air Filtration for Industrial and/ or Large Cities

Gas turbine power plants located in large cities and industrial can experience GT degradation caused by erosion, fouling and corrosion.

The contaminants present in large cities are largely based on season and can vary accordingly throughout the year. Smog, smoke and pollution are often visible in large cities but can also been seen in rural countryside in times of high winds. Adequate gas turbine inlet filtration in such environments often requires multiple stages. The components of a multi-stage filtration system most often include:

  • Pre-filter (MERV 8-13) to remove the larger particles and lengthen the life of the final filter
  • High-efficiency (MERV 14-16 to HEPA grade) to remove smaller particulates which often cause the most damage

Gas turbine inlets designed for large cities and/or industrial areas often include weather hoods to protect the system against wind, snow and rain.

Gas turbines installed in heavy industrial areas have additional concerns, apart from those described earlier, including exhaust stacks in the form of gases, particles and aerosols. These are all in submicron size and hence, difficult to filter. These particles can accumulate on compressor blades and lead to fouling. There are contaminants in industrial locations that are not easily visible unless present close to the localized source. These include dust from mining operations, paper mills, saw mills, foundries etc. GT inlet filtration systems for industrial locations should be designed specifically to address local plant pollutants and emissions which may require HEPA grade filters to remove submicron particulates. In additional, diverting the inlet air flow away from such emissions, the volume of emission ingested into the turbine can be reduced.

Gas turbine inlet air filters offered by AFC are recommended in many of these cases to reduce the frequency of online and offline water washes often required to eliminate sticky aerosols from oil vapors from lubrication systems or unburned hydrocarbons emitted from exhaust stacks.

GT Inlet Air Filtration for Desert and Dry Areas

In deserts the climate is hot and dry, with large amounts of dust and little to no vegetation. These areas often face sand storms, rapidly loading the filters beyond their dust holding capacity. Although most deserts and desert like environments are found in Africa (Sahara desert in Africa is the largest desert in the world), Middle East and certain Asian regions, there are smaller localized areas that face high dust concentration, which include gas turbines situated near quarries, loess, dried lakebeds, dirt tracks, industrial areas, construction sites and dry agricultural lands.

In deserts and dry areas dust (in the form of substances such as finely ground desert rock/pavement) is the main contaminant. With little to no vegetation protecting the desert floor, high winds often lead to large amounts of dust (ranging from 500μm to submicron size) being blown up into the air and surrounding atmosphere.

The major objective GT inlet filtration in a desert/dry area is dust removal. Deserts located in coastal regions such as California, Arizona and Texas for example, can experience periods of dense fog and high humidity which, combined with desert dust, can form in a thick coating on the filter surface thus reducing filtration effectiveness. Inadequate filters can load quickly in such circumstances, result in high pressure losses and require frequent filter change-outs.

Advanced Filtration Concepts (AFC) offers a new and comprehensive range of gas turbine Inlet air filters for deserts and dry areas and their associated conditions. They are capable of providing continuous, uninterrupted operation for prolonged time periods in the desert environment, with enhanced efficiency.

GT Inlet Air Filtration for Tropical Areas

Typically tropical areas are distinguished by their hot climate, high humidity, monsoons, high winds and insect swarms. When it comes to gas turbine power plants blade erosion isn't much of a concern in tropical areas as extensive plant life help keep dust levels low. Factors which can affect the GT inlet filtration are typhoons, the remote location of the plant, insects and dust kicked up from unpaved roads.

Although dust is usually minimal because of the abundant vegetation, if there is construction being done anywhere near the GT inlet dust concentrations may be higher. Unpaved roads might also add more dust in the air. Pollen is another factor. Salt is often an issue in tropical areas because of the presence of moisture and high humidity.

Little seasonal fluctuations can be seen apart from periods of heavy rainfall.

While selecting the correct gas turbine inlet filtration system for tropical environments, these factors are to be considered:

  • Typhoons
  • Dust
  • Insects
  • System remoteness

The major contaminants include:

  • Water (Due to rain)
  • Insects
  • Salt (If location is along or nearby coast)

Tropical environments usually need gas turbine inlet filtration systems that are able to withstand heavy rain. As a primary protection, weather hoods are used sometimes with extended area insect screens to prevent insects from obstructing the inlet air flow.

GT inlet filters include:

  • Coalescers
  • Pre-filters
  • Final filter

Backed with over 30 years in the gas turbine inlet air filtration industry Advanced Filtration Concepts (AFC) provides new and innovative air filtration products and services for gas turbine power applications for tropical environments and related conditions.