ClearSign Combustion says it has successfully demonstrated an 80 percent to 90 percent reduction in NOx emissions by retrofitting a conventional off-the-shelf commercial burner in a system designed to closely resemble a standard commercial firetube boiler.
CEO Rick Rutkowski says the system demonstrates that ClearSign’s Duplex technology may be adapted to many of the hundreds of thousands of similar commercial and industrial boilers in use worldwide.
Previously, the company demonstrated that the Duplex Burner architecture can reduce NOx emissions as low as 2 PPM and maintain carbon at low single-digit levels while eliminating costly external flue gas recirculation, Rutkowski says. These earlier results were produced in a vertically up-fired configuration, typical of a range of refinery heater types.
In response to interest from prospective development partners and customers, ClearSign’s most recent effort tested the Duplex architecture’s ability to produce similarly disruptive performance improvements in the horizontally fired configuration that is commonly used in so-called package boilers.
Rutkowski says the test showed the ClearSign system reduced NOx emissions by more than 80 percent, from 50 PPM to below 10ppm in continuous operation. It also showed periodic reductions in NOx of up to 90 percent with emissions as low as 5 PPM and maintained CO at below 10 PPM.
The company operated the system at thermal output of up to 800,000 Btus/hour and says it’s on track to increase this to 2 million Btus/hour as early as the end of the quarter.
According to Rutkowski, the emissions performance of the modified system at 10 PPM of NOx is already superior to many ultra-low NOx burners on the market; another significant advantage is that it requires no external flue gas recirculation to attain these low NOx emissions. This represents a major reduction in operating costs including significant savings from improved energy efficiency, he says.
In the coming weeks, the company has set a goal to make additional improves to the system to achieve continuous NOx emissions at or below 5 PPM while also reducing CO to low single-digit levels.
Last December, the EPA released its final Clean Air Act standards for industrial boilers and incinerators, rules that the agency says will apply to less than 1 percent of those machines.
The standards now cover only the highest emitting boilers and incinerators, typically operating at refineries, chemical plants and other industrial facilities.