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Title	Gas Cofiring for Performance Improvement and Emissions Reduction in Stoker Boilers
Creator	Waterland, L. R.; Mason, H. B.; Gemmer, R. V.; Drennan, Scott A.
Publisher	Digitized by J. Willard Marriott Library, University of Utah
Date	1999
Spatial Coverage	presented at San Francisco, California
Abstract	Cofiring a small amount of gas in solid-fuel fired boilers is an efficient and economical way to resolve a variety of emissions and performance problems. GRI has developed and demonstrated a specialized cofire retrofit package featuring dual, opposed, high pressure drop gas burners to control the combustion over the solid fuel. Earlier demonstrations on coal-fired stokers have shown cofire to reduce emissions, enhance performance, increase efficiency and lower operating costs. In the present work, the cofire package has been applied to another eight coal-fired stoker boilers at five sites. At the first site, cofire reduced particulate up to 60 percent for 20 percent gas firing. At the second site, gas cofire was used to reduce NOx emissions by 20 percent for 20 percent cofire. At the third site, cofire achieved 15 percent NOx reduction for 10 to 15 percent cofire, and allowed routine smokeless startup and load ramping. At the fourth site, cofire allowed the recovery of formerly derated 20 percent of boiler capacity with 10 percent cofire. At the fifth, 7 percent cofire allowed a flue gas recirculation system formerly needed for opacity control to be disconnected.
Type	Text
Format	application/pdf
Language	eng
Rights	This material may be protected by copyright. Permission required for use in any form. For further information please contact the American Flame Research Committee.
Conversion Specifications	Original scanned with Canon EOS-1Ds Mark II, 16.7 megapixel digital camera and saved as 400 ppi uncompressed TIFF, 16 bit depth.
Scanning Technician	Cliodhna Davis
ARK	ark:/87278/s60r9s1g
Setname	uu_afrc
ID	11241
Reference URL	https://collections.lib.utah.edu/ark:/87278/s60r9s1g

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Title	Page 7
Format	application/pdf
OCR Text	Show Reduction in N O x emissions was commensurate to the displacement of the coal by gas, as shown in Figure 4. Since particulate reduction was the primary objective, no attempt was made to fire the gas burners fuel rich to minimize overall N O x from the coal and gas flames. 0.6 0.1 •• 0.0 0% AHi^iLood- 1 _HicfiLoo_-2 20% 40% 60% Gas Cofire, % 80% Figure 4. Ford N O , Emissions Results. Overall boiler efficiency generally increased with cofire due to reduction in excess air level and generally improved carbon burnout in flyash. Figure 5 shows the efficiency response to cofire for the two burner configurations at high load. This efficiency increase was consistent with a reduction in excess oxygen of about 1.5- percent for 20 percent gas cofire. o.u - a$ 2.5 - „ O O) c 2.0 • CO s o > 1-5- •cuS> i.o-o sc _ M - 0) m oo - -0.5 - • • - .' 4_ ,* • ' - ^ ^ ^ A _ .-* m m ." A -A ^ ^ ^ "^~ A ^^*. A ^^^-^^ ^ - A _ High Load - 1 _ High Load - 2 0% 10% 20% 30% 40% Gas Cofire, % 50% 60% Figure 5. Ford Efficiency Results. 7
Setname	uu_afrc
ID	11231
Reference URL	https://collections.lib.utah.edu/ark:/87278/s60r9s1g/11231