Release and distribution of fuel nitrogen in one-dimensional coal dust flames

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6184884

Midkiff, Jr, K C

Experiments on the effect of stoichiometry, coal type, and particle size on the distribution of fuel nitrogen in seven, fuel-rich, one-dimensional, pulverized-coal/O2/Ar flames are reported. Fuel-N was inventoried by measuring gas-phase concentrations of HCN, NH3, NO, and N2, and solids nitrogen content as functions of reaction time. Complementary measurements of gas and particle temperatures, concentrations of major gas species, and proximate/ultimate compositions of solids samples were also made. Experimental fuel nitrogen balances were generally complete. Coal-N release is more rapid and extensive for leaner stoichiometries and smaller particles. Leaner flames favor increased NO and decreased NH3 and HCN levels. Increasing particle size yields reduced early NO formation and slower NO destruction at long residence times, but particle size has little influence on the fraction of fuel-N ultimately converted to NO. The predominant gas-phase nitrogen species in all flames is N2. First order activation temperatures of 6000-8000 K found for bituminous and subbituminous coal-N release are elevated only marginally by corrections applied to account for heterogeneous combustion concomitant with devolatilization. First-order fits to size-graded coal-N release data indicate lower apparent activation temperature with increasing particle size. Size effects are successfully explained by a model incorporating first-order coal-N devolatilization, diffusional mass transfer, and first-order volatiles-N redeposition to the char.

• Research Organization: Kentucky Univ., Lexington (USA)
• OSTI ID: 6184884
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
014000* -- Coal
Lignite
& Peat-- Combustion
ACTIVATION ENERGY
AMMONIA
ARGON
BITUMINOUS COAL
BLACK COAL
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
COAL
COAL RANK
COMBUSTION KINETICS
CYANIDES
DEVOLATILIZATION
DISTRIBUTION
ELEMENTS
EMISSION
ENERGY
ENERGY SOURCES
EQUATIONS
FLAMES
FLUIDS
FOSSIL FUELS
FUEL-AIR RATIO
FUELS
GASES
HYDRIDES
HYDROCYANIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
KINETIC EQUATIONS
KINETICS
MASS TRANSFER
MATERIALS
NITRIC OXIDE
NITROGEN
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NITROGEN OXIDES
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PARTICLE SIZE
PULVERIZED FUELS
RARE GASES
REACTION KINETICS
SIZE
SUBBITUMINOUS COAL
TIME DEPENDENCE