A Lens on Efficiency

Advancements in thermal imaging technology are providing plant engineers with new insights into combustion conditions.
By Anna Simet | December 23, 2013

When it comes to thermal imaging, Enertechnix’s roots run deep, particularly in the pulp and paper industry. The company has made several advances since the early 1990s and has extended its technology to waste-to-energy plants and, just recently, its first woody biomass power plant—the Factory Sales & Engineering-supplied boiler at Abengoa Bioenergy Biomass of Kansas. 

Via a specific infrared wavelength, Enertechnix’s PyroOptix camera filters all combustion gases common with the boiler, providing biomass plant operators with advanced views of material feeding on the biomass grate floor, temperature profile information regarding the impact of potential slagging in the upper furnace, and clear images and crucial data to indicate what’s happening throughout the boiler combustion process. “Just as you’d be able to see with your naked eye,” says Dave Suplicki, director of sales and marketing.  “In the biomass arena, we can now look at actual feed chutes and what’s going on in the waste streams being burned. Prior systems used video cameras to look at flame patterns. Now, if there’s a fireball, we can actually study the health and management of the process.” 

As Suplicki points out, thermal imaging, in terms of heat patterns or heat signatures, is very common in the power industry and has been used for 20 years. “But we work at this specific wavelength, combined with some very advanced optics and optical lenses, so the camera can provide views through smoke and ash in very hot environments, anywhere from 500 degrees (Fahrenheit) up to 3,200 degrees.”

The camera uses lens tubes that can be inserted into the boiler observation windows/doors and manipulated, which greatly expands areas that can be observed. “We’ve brought into play the ability to view the upper furnace, where a lot of boiler cleaning activities are done,” Suplicki says. “Using image processing, we can take snap shots from when it’s clean and as slag builds up in different areas over time. By recording it pixel by pixel we can do a comparison of what it should be, and what it is, and create a slag index, which can tell you where to clean instead of trying to guess.”

Enertechnix’s technology is relatively new, and as Suplicki points out, things don’t move quickly within the industry. “It takes time to introduce new process stuff, but slowly and surely, we’re expanding upon the fact that we can provide better input. Boiler operators are able to see things they never have before, and can make decisions from them. By providing specific information used in cleaning decision making processes, it can result in cost savings. Right now, decisions are based on inputs that are nonvisual, such as pressure and temperatures, common recipes that have been put together and traditionally used.”

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Video Vs Thermal Imaging in Boilers

While thermal imaging may provide advantages over traditionally used video cameras, there are upsides to both, according to Sonnick Clausen. For one, the video camera is typically smaller and significantly cheaper than a thermal camera. “Most customers go for an inspection system with a video camera unless features of the thermal camera are needed,” Clausen says. “Nevertheless, the image quality is mostly superior to the thermal camera in boilers, due to scattering of light by fine particles and light from soot particles.” 

Thermal imaging is a nice tool in grate-fired systems, as the view is far better than using video, according to Clausen, and it provides details and behavior during the whole cycle from inlet to outlet.

Color video cameras are mostly used in situations where visible light is emitted—flame light from soot—or light from a bright source is reflected or absorbed by surfaces or particles. “The video camera can be used in most situations in boilers, if features can be seen by the human eye,” Clausen says.

As a rule of thumb, operators of boilers with soot and small ash particles will have a view 10 times better with IR than VIS. 

Clausen's company Pyrooptic is manufacturer of high-quality industrial rigid endoscopes for looking inside high temperature processes, an instrument used to examine the interior of boilers, burners and flames during operation. Clausen says the best solution for burner and flame optimization is an inspection system combining both video and thermal imaging. "Technology has advanced to a level that permits high speed visual and thermal videos to be obtained simultaneously using the same endoscope optics," he adds, "for example, snap-shot  infrared images of the turbulent mixing of gas and fuel in small and large power plant flames can be recorded together with visual image showing ignition details."

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Author: Anna Simet
Managing Editor, Biomass Magazine