Burner Component Upgrades for Wall-Fired Coal Burners: RPI Results and Experiences

Improving the operation and emissions performance of coal fired utility boilers equipped with first and second-generation wall fired low NO_x coal burners is of significant interest to many utility companies today. The recent development of cost effective components for existing first and second-generation wall fired burners permits better combustion performance, increased wear life reliability, and decreased NO_x emissions. Existing air register systems can typically remain in place, resulting in reduced capital cost and reduced outage time for installation. Computational fluid dynamic (CFD) modeling is used to assist in the design of key burner components and operating conditions that enable further reduction of NO_x emissions. Results include better flame attachment, better airflow recirculation patterns, and early ignition and pyrolysis of the coal in a more controlled primary combustion zone. NO_x reductions of 10–20% have been demonstrated using burner component upgrades with improved overall boiler operation. This paper gives a brief description of the component-only retrofit design methodology that Riley Power Inc., a Babcock Power Inc. company developed for other OEM’s low NO_x burners in wall-fired furnaces. The numerical modeling to assist in the design of these low NO_x systems and the corresponding CFD results are also discussed.