Process Sensors Corporation

FEGT Temperature Measurement and Control for Industrial Boilers

For those of us who don't live in the tropics or have electric heating, a boiler provides heat for our homes. A boiler is a tank or other vessel in which a fluid is circulated and heated. Boilers are not just for the home, as they are also used in industrial processes, power generation, and sanitation. The fuel source for a boiler may be natural gas, coal, oil, wood, trash or even nuclear fission.  

Industrial Boiler Types

There are three main types of boilers used for industrial processes or power generation: fossil fuel boilers, biomass or hog fuel boilers, and recovery boilers.

Fossil FuelTemperature measurement of FEGT hog fuel industrial boiler

Fossil fuels such as coal, oil and natural gas are burned to heat water into steam.  


Like fossil fuels, biomass fuels may be burned to heat water into steam. Biomass fuels are often an unrefined mix of wood processing byproducts including bark, chips, wood fines and strands known as “hog fuel.”  Biomass fuels may also be supplemented with a fossil fuel such as oil or natural gas to compensate for variation in moisture and energy content.   


In a recovery boiler, organic materials are combusted with black liquor (a black, syrupy, organic byproduct of producing paper) to heat water into steam.

Boiler Burning Process

Regardless of the type of boiler, it is important to measure the burner/flame and steam temperatures in an industrial boiler, but it is also important to monitor Furnace Exit Gas Temperature (FEGT) for optimal performance and to ensure the health of boiler. Excessive FEGT can result in unnecessary fuel consumption,  refractory and boiler tube fouling or damage, and unwanted levels of oxygen-nitrogen oxides (NOx) which increase smog, acid rain and ozone.   

Temperature Measurement Points

A Process Sensors Corporation (PSC) “Infra-boiler” non-contacting infrared detection Pyrometer system mounted on the exterior of a boiler can be used to measure the temperature of FEGT and/or the boiler flame. Non-contacting temperature measurement is very important as contact-type thermocouples can only measure boiler wall temperature rather than the center of the boiler which is much hotter. Soot and fly ash deposits can insulate thermocouples resulting in inaccurate measurements. The “Infra-boiler” system triggers an alarm when the highest FEGT temperature for efficient operation is reached, thus preventing fouling or damage to boiler tubes as well as unwanted NOx emissions.  

“Infra-Boiler” system: Metis MY45 or MY46 pyrometer, graphical Sensor Tools software and all accessories needed for proper cooling and sighting.

To learn more about how PSC can optimize your boiler operation, please fill out the contact form below.

Featured Solutions

Tell us about your application. Fill out the form below and we'll put you in touch with an IR expert.