Page 534 - Dust Explosions in the Process Industries

Assessment of lgnitability 50 1

Figure 7.25 Ignition of a dust cloud in the
Codbert-Creenwald furnace. For a much clearer
picture, see Color Plate 10.

550

- 500
U
e
W
05
3
c
6
g 450
a
6
I-
z
0
2 400
E
x
3
z
z
x
350
I 300 g/m: Figure 7.26 Influence of the residence time of dust
300 clouds in the Codbert-Creenwald furnace on the
minimum ignition temperature, with three different
0.1 0.2 0.3 o,4
concentrations of brown coal dust (From Criesche
and Bran& 1976).
RESIDENCE TIME OF DUST IN FURNACE (SI
coal dust gave a minimum ignition temperature of 310°C. This is lower than all the data
in Figure 7.26, but about 100°C higher than the very low value found for a residence time
of >1 s and 500 g/m3 dust concentration. This evidence should be kept in mind when apply-
ing data from standard Godbert-Greenwald furnace tests in industrial practice.

7.8.2.2
BAM Furnace

In Germany, an alternative furnace was developed by Bundesanstalt fur Materialpriifung,
as described by Leuschke (1966a, 1966b). The furnace is illustrated in Figure 7.27.