Environmental Characterization and In-situ Testing for Gas Turbine Inlet Filter System Selection

The importance of proper inlet air filtration for the modern gas turbine is understood within the industry with respect to potential performance degradation due to compressor fouling, erosion, and corrosion. For optimal performance, manufactures of air inlet filter systems recommended that the design of a filter system be tailored to the local environmental conditions. A poor performing inlet filter system can have a large negative impact on turbine performance such as increased heat rate, reduced power due compressor fouling, and /or high filter pressure drop. Typically, these conditions are generalized such as urban, rural, industrial and coastal. These generalizations are often inadequate. And at many gas turbine sites little data is known about ambient aerosol contaminates. This paper discusses the various methods for identifying these conditions which affect the performance of a filter system. The discussion will include traditional methods of aerosol sampling and a novel method of in-situ testing of multiple filters. The later method allows for comparative analysis of different inlet filters while exposed to a real turbine operating environment. The in-situ method has the benefit of exposing the filters to the varying conditions of the operating site but does require more time and specialized equipment. Example data are given in the paper and a summary of how these data would impact the operation of a gas turbine air inlet filter system.