Combustion Characteristics and NO_x Emissions of Two Kinds of Swirl Burners in a 300-MW_e Wall-Fired Pulverized-Coal Utility Boiler

Abstract

Measurements were performed in a 300-MW_e wall-fired pulverized-coal utility boiler. Enhanced ignition-dual register (EI-DR) burners and centrally fuel rich (CFR) swirl coal combustion burners were installed in the bottom row of the furnace during experiments. Local mean concentrations of O₂, CO, CO₂ and NO _x gas species, gas temperatures, and char burnout were determined in the region of the two types of burners. For centrally fuel rich swirl coal combustion burners, local mean CO concentrations, gas temperatures and the temperature gradient are higher and mean concentrations of O₂ and NO _x along the jet flow direction in the burner region are lower than for the enhanced ignition-dual register burners. Moreover, the mean O₂ concentration is higher and the gas temperature and mean CO concentration are lower in the side wall region. For centrally fuel rich swirl coal combustion burners in the bottom row, the combustion efficiency of the boiler increases from 96.73% to 97.09%, and NO _x emission decreases from 411.5 to 355 ppm @ 6% O₂ compared to enhanced ignition-dual register burners and the boiler operates stably at 110 MW_e without auxiliary fuel oil.

Keywords:

• NO _x
• Pulverized coal
• Swirl burner
• Utility boiler

We thank M. Costa and J. L. T. Azevedo for the support to this work. This work was supported by Hi-Tech Research and Development Program of China (Contract No. 2007AA05Z301), the Ministry of Education of China via the 2004 New Century Excellent Talents in University (Contract No. NECT-04-0328), Heilongjiang Province via 2005 Key Projects (Contract No. GC05A314), Key Project of the National Eleventh-Five Year Research Program of China (Contract No. 2006BAA01B01), the National Basic Research Program of China (Contract No. 2006CB200303), and the Post-doctoral Foundation of Heilongjiang Province LRB07-216.