Mechanisms of nitrous oxide formation in coal flames

Technical Report · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5344736

Kramlich, J C; Cole, J A; McCarthy, J M; Lanier, W S

The paper gives results of a study which investigated an unknown mechanism by which N{sub 2}O is formed in coal flames, using both detailed kinetic modeling and plug-flow simulator experiments. The mechanism has considerable importance in determining the influence of common and advanced NOx control strategies on N{sub 2}O. Significant N{sub 2}O emissions have been observed from coal- and oil-burning power plants but not from industrial gas flames, even when they are doped with an equivalent amount of fuel nitrogen. Kinetic modeling suggests that net N{sub 2}O is unlikely to form within flame zones because of its rapid removal by: N{sub 2}O + H yields N{sub 2} + OH. Also, reduction of NO on coal char, or coal char oxidation, can be significant N{sub 2}O sources only if the rates are many times their published values. However, both kinetic modeling and experiments show that, if HCN appears in the gas phase between 1150 and 1500 K, it will be partially converted to N{sub 2}O. The source of HCN may be either direct devolatilization or a char gasification reaction. This suggests that the N{sub 2}O which appears in coal flames may originate from the homogeneous reaction of devolatilized char nitrogen in the fuel-lean post-flame region. The kinetics indicate that the formation is principally through the reaction: NCO + NO yields N{sub 2}O + CO.

• Research Organization: Energy and Environmental Research Corp., Irvine, CA (USA)
• OSTI ID: 5344736
• Report Number(s): PB-90-103805/XAB
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010900 -- Coal
Lignite
& Peat-- Environmental Aspects
014000* -- Coal
Lignite
& Peat-- Combustion
54 ENVIRONMENTAL SCIENCES
540120 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AIR POLLUTION
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
COAL
COMBUSTION PRODUCTS
ENERGY SOURCES
FLAMES
FOSSIL FUELS
FUELS
KINETICS
MATERIALS
MATHEMATICAL MODELS
NITROGEN COMPOUNDS
NITROGEN OXIDES
NITROUS OXIDE
OXIDES
OXYGEN COMPOUNDS
POLLUTION
REACTION KINETICS