Stoichiometry and coal-type effects on homogeneous vs. heterogeneous combustion in pulverized-coal flames

Journal Article · Sun Jun 01 04:00:00 EDT 1986 · Combust. Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(86)90144-6· OSTI ID:5214652

Midkiff, K C; Altenkirch, R A; Peck, R E

Results of experiments to determine the extent of heterogeneous combustion in the rapid-devolatilization regime of fuel-rich bituminous and subbituminous coal-dust flames are reported. Major gas concentrations, gas and particle temperatures, and solids proximate and elemental compositions were measured as functions of residence time in pulverized-coal/O/sub 2//AR flames stabilized on a flat-flame burner. Proximate fixed carbon and volatile matter measurements are corrected to account for devolatilization exceeding that predicted by ASTM proximate analysis. The corrected proximate data are used to determine the fraction of volatile matter consumed heterogeneously in situ and the fraction released to the gas phase by pyrolysis. Seven to thirty-five percent of the initial corrected volatile matter is removed heterogeneously. A mass transfer analysis is applied to predict a time dependent critical particle size such that the volatiles flux emerging from larger particles is sufficient to prevent surface oxidation. Critical particle radii as large as 39 ..mu..m are calculated. Results of the volatile matter partitioning and critical radius calculations indicate that heterogeneous combustion is more important in the leaner flames and for the subbituminous coal.

• Research Organization: Dept. of Mechanical Engineering, Univ. of Kentucky, Lexington, KY 40506
• OSTI ID: 5214652
• Journal Information: Combust. Flame; (United States), Journal Name: Combust. Flame; (United States) Vol. 64:3; ISSN CBFMA
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
014000* -- Coal
Lignite
& Peat-- Combustion
ARGON
BITUMINOUS COAL
BLACK COAL
BURNERS
CARBONACEOUS MATERIALS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL
COAL FINES
COMBUSTION KINETICS
DATA
DECOMPOSITION
DEVOLATILIZATION
ELEMENTS
ENERGY SOURCES
EXPERIMENTAL DATA
FLAME PROPAGATION
FLUIDS
FOSSIL FUELS
FUELS
GASES
INFORMATION
KINETICS
MASS TRANSFER
MATERIALS
MATTER
NONMETALS
NUMERICAL DATA
OXIDATION
OXYGEN
PARTICLE SIZE
PYROLYSIS
QUANTITY RATIO
RARE GASES
REACTION KINETICS
SIZE
STANDARDS
STOICHIOMETRY
SUBBITUMINOUS COAL
TEMPERATURE MEASUREMENT
THERMOCHEMICAL PROCESSES
TIME DEPENDENCE
VOLATILE MATTER