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Dear all,

What is the purpose of the dew point transmitter at GE Frame 6 Gas Turbine?

My turbine uses Panametrics CMX1

Thank you.

Dew point sensors are generally used to determine the humidity of the axial compressor inlet air.

This may be done for a variety of reasons, depending on the configuration of the unit. It may be done for biasing Water or Steam Injection used to reduce NOx emissions or Power Augmentation. It might be done for performance monitoring purposes. It might be done for combustion reference temperature calculation.

In the past, specific humidity sensors were used, which caused a lot of issues (relative humidity and specific humidity are not the same) when trying to determine whether or not the humidity sensor was working properly. (Specific humidity is on one side of the psychometric chart; relative humidity is on the other.)

Dew point sensors and humidity sensors (either specific or relative) usually require periodic maintenance, and most sites do not perform any maintenance. Usually, it's not easy or convenient or easy to access the sensor, but optimal turbine operation depends on a properly maintained and functioning dew point or humidity sensor, when the unit is equipped with one.