Influence of coal composition on the fate of volatile and char nitrogen during combustion

Conference · Fri Jan 01 04:00:00 EST 1982 · Symp. (Int.) Combust., (Proc.); (United States)

OSTI ID:5636206

Chen, S L ^[1]; Heap, M P; Pershing, D W; Martin, G B

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1. Energy and Environmental Research Corp., Irvine, CA

Fifty coals from North America, Europe, Asia, South Africa and Australia were burned in a 21 kW, refractory-lined tunnel furnace to determine the influence of coal properties on the fate of volatile nd char nitrogen. Excess air fuel NO emissions (as determined by combustion in Ar/O/sub 2//CO/sub 2/) ranged from 415 to 1380 ppM with a premixed burner. These results correlated with total fuel nitrogen, inert pyrolysis HCN yield, and non-volatile nitrogen content, rather than with the geographic origin of the coal. Minimum staged NO emissions (at optimum first stage stoichiometry) ranged from 140 to 380 ppM. Detailed in-flame measurements indicated that as first stage stoichiometry (air/fuel) was reduced, first stage NO formation decreased, but was ultimately offset by increases in oxidable gaseous nitrogen species and solid phase nitrogen retention. TFN (NH/sub 3/ + NO + HCN) generally increased with increasing fuel nitrogen and the species distribution was dependent upon coal rank. In general, HCN was greater than NH/sub 3/ with bituminous coals, but less than NH/sub 3/ with subbituminous and lignite coals. Second stage TFN conversion to exhaust NO decreased as the TFN distribution was shifted in favor of HCN and NH/sub 3/. Char nitrogen conversion was generally low (less than 20 percent). Exhaust emissions were correlated in terms of the gas phase TFN and the char nitrogen entering the second stage. Increasing heat extraction generally reduced exhaust NO emissions via a complex mechanism. Reducing second stage flame temperatures had little effect on the concentration and speciation of the XN species leaving the first stage, and on the conversion of solid phase nitrogen in the second stage. However, it dramatically decreased the second-stage conversion of gas phase TFN to exhaust NO. The controlling mechanism appears to be selective NO reduction by NH/sub i/ species. The effectiveness of increased heat extraction rate was also found to depend heavily on the coal composition.

• OSTI ID: 5636206
• Report Number(s): CONF-820801-
• Conference Information: Journal Name: Symp. (Int.) Combust., (Proc.); (United States)
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
014000* -- Coal
Lignite
& Peat-- Combustion
500200 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
AMMONIA
CARBONACEOUS MATERIALS
CHALCOGENIDES
COAL
COMBUSTION PRODUCTS
CYANIDES
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDRIDES
HYDROCYANIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MATERIALS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS