An analysis of the ignition of coal dust clouds

Journal Article · Mon Mar 01 04:00:00 EST 1993 · Combustion and Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(93)90159-Z· OSTI ID:6491167

Zhang, Dong-ke; Wall, T F ^[1]

---

1. Univ. of Newcastle (Australia)

The ignition or explosion of coal dust clouds is of interest in the fields of fire safety, and the combustion of pulverized fuel, as well as being a fundamental issue in combustion science. Ignition of coal particles is the result of a complex interaction among different mechanisms including particle heating, devolatilization, heterogeneous oxidation, and gas-phase oxidation and transport phenomena. Both theoretical and experimental studies on single particles have been well developed, with considerable experimental precision and validation of the predictions. However, experiments have shown that the ignition temperatures could be reduced by as much as 300 C due to the concentration (cooperative influence) effect associated with particle clouds. While the authors have observed that the ignition temperature decreases with increasing particle size using a drop-tube technique involving the injection of a small mass ([approximately]2-5 mg) of coal particles, Gururajan has reported that this effect is not clear (for the same fuel) in continuous ignition experiments involving a higher loading of coal. The theoretical analysis of coal dust cloud ignition is limited at present to the case of heterogeneous ignition on the surface of the particles, which does not allow for this effect. This brief communication extends the energy equations of Krishna and Berlad to include coal volatile matter (VM) release and the homogeneous ignition of VM in the gas phase of the cloud. The effects of particle size on the ignition temperature and ambient oxygen concentration on ignition mechanisms, predicted by this extension, are then examined.

• OSTI ID: 6491167
• Journal Information: Combustion and Flame; (United States), Journal Name: Combustion and Flame; (United States) Vol. 92:4; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
014000* -- Coal
Lignite
& Peat-- Combustion
AEROSOLS
CARBONACEOUS MATERIALS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL
COAL FINES
COLLOIDS
COMBUSTION KINETICS
CORRELATIONS
DEVOLATILIZATION
DISPERSIONS
DUSTS
ENERGY SOURCES
EXPLOSIONS
FOSSIL FUELS
FUELS
IGNITION
KINETICS
MATERIALS
MATHEMATICAL MODELS
MATTER
OXIDATION
REACTION KINETICS
SOLS
TEMPERATURE DEPENDENCE
VOLATILE MATTER