Effect of Stoichiometric Ratio of Fuel-Rich Flow on Combustion Characteristics in a Down-Fired Boiler
Publication: Journal of Energy Engineering
Volume 143, Issue 3
Abstract
Numerical simulations and industrial experiments were conducted to study the effect of the stoichiometric ratio of the fuel-rich flow (0.46, 0.49, 0.51, 0.53, and 0.55) on the flow, combustion, and emission characteristics in a 600-megawatt electric () supercritical down-fired boiler with multiple-injection and multiple-staging combustion technology. The simulation results indicate that as the stoichiometric ratio of the fuel-rich flow increases from 0.46 to 0.55, the flow fields all form a symmetric W-shaped pattern; this is identical to the symmetric temperature distributions obtained experimentally. The ability of downward coal/air flows to entrain high-temperature gases from the recirculation zone weakens, and the airflow declination angle in tertiary-air regions and the downward flame penetration depth decrease. Coal burnout is enhanced. The temperature in the lower furnace rises, the high-temperature () area gradually increases from 64 to , the carbon in the fly ash at the furnace exit decreases from 9.41 to 4.23%, and emissions increase from 860 to at 6% .
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Acknowledgments
This work was supported by the National Natural Science Foundation of China (Grant No. 51576055 and 51406043), the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (Grant No. 51421063), the Hei-longjiang Postdoctoral Fund (Grant No. LBH-Z12133), and the Fundamental Research Funds for the Central Universities (Grant No. HIT.NSRIF.20120735081).
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Published In
Journal of Energy Engineering
Volume 143 • Issue 3 • June 2017
Copyright
©2016 American Society of Civil Engineers.
History
Received: Apr 12, 2016
Accepted: Aug 18, 2016
Published online: Oct 21, 2016
Discussion open until: Mar 21, 2017
Published in print: Jun 1, 2017
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