Page 432 - Dust Explosions in the Process Industries

Ignition of Dust Clouds and Dust Deposits 399

700
0 SIMULATED I

lor5 10-~ 10-3 10-2 10-1 1 10
VOLUME OF CORK OUST SAMPLE fmq

Figure 5.8 Dependence ofminimum self-ignition temperature for cylindrical cork dust samples on
sampl'e volume, using experimental data from Leuschke (198 1) and computer simulation results
from Liang and Tanaka (1987b, 1988).

10-3 10-2
VOLUME OF CORK DUST SAMPLE [m?

Figure 5.9 Influence of dust sample volume and ambient air temperature on the induction time to
self-ignition of cylindrical deposits ofcork dust. Ta,mjnis the minimum ambient air temperature for self-
ignition, using computer simulation results (From Liang and Tanaka, I987b).

Figure 5.8 shows the minimum self-ignition temperature as a function of sample
volume for cylindrical cork dust samples, as determined experimentally by Leuschke
(1981) and by computer simulation by Liang and Tanaka (1987b, 1988).
Figure 5.9 shows the increaseof the induction time to ignition (i.e., the time from intro-
ducing the dust sample into air of temperature T, to ignition of the sample) with increas-
ing sample volume and decreasing T,.
Leuschke (1981) provided no data for cork dust correspondingto the simulationresults
in Figure 5.9. However, he gave a set of experimental data for another natural organic
dust, which exhibit trends that are very close to those of the results in Figure 5.9.