Combustion of dense streams of coal particles
Ignition of the high volatile isolated coal particles in vitiated environment seems to occur heterogeneously at the leading edge of the particle. Volatiles are observed to be ejected upward as jets in the direction of the convective flow but only after heterogeneous ignition. The volatiles burn in the gas phase homogeneously and form a wake flame; a black inner zone (unburned volatile) is formed (see Fig.A.3 for many common characteristics of isolated flames).Intermittent volatile ignition and combustion are observed to occur during the combustion process for a few of the isolated particle combustion experiments on high volatile non-swelling coal. The medium volatile coal particles ignite faster than the high volatile coal; but the intermittent ignition is not observed. The low volatile isolated coal particles combust in shorter time. The isolated char particles ignite at the surface of the particle heterogeneously with little volatile ejected, yet are not sufficient to form a volatile flame, resulting in a subsequent heterogeneous combustion. A group flame is formed for the two-particle arrays at closer interparticle spacing (Fig.A.4). Also, intermittent ignition does not occur for the high volatile particles when the two particles are at farther distances which suggests that radiation interaction between the particles might be occurring. However this conclusion is purely speculative. The char arrays experience heterogeneous ignition at the leading edge; combustion proceeds heterogeneously.
- Research Organization:
- Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG22-90PC90310
- OSTI ID:
- 6639949
- Report Number(s):
- DOE/PC/90310-T10; ON: DE93013072
- Country of Publication:
- United States
- Language:
- English
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