Page 54 - Dust Explosions in the Process Industries

Dust Explosions: An Overview 27

500 -
-
c
2 400 -
I
m
x
0 m
5 300 -
x
4
c
4
CL
2 200 -
- 2
A
m -
2 100
E! Figure 1.I 7 Influence of chemistry (starch or
protein) and specific surface area of natural
01 I I I I organic materials on maximum rate of pressure
0 01 02 0.3 0.4
rise in a closed 1.2 liter Hartmann bomb (From
SPECIFIC "ENVELOPE" SURFACE AREA Im*/gl Eckhofc 7 977/1978).
natural organic dusts. Reasonable agreement with experiments was found for a range of
food and feedstuffs dust, fish meals, and cellulose.
Another example of the influence of dust chemistry on the explosion kinetics is shown
in Figure 1.18. The heats of combustion of PVC and polyethylene are not very differ-
ent. Closed-bomb experiments also find about the same maximum pressure for very
small particle sizes. However, the chlorine in the PVC causes quite a dramatic drop in

0 100 200 300 400

POLYETHYLENE

0 100 200 300 400
MEDIAN PARTICLE SIZE Iuml

Figure 1.I 8 The influence of chlorine in molecule of dust material on maximum explosion pressure
an'd maximum rate of pressure rise in 1 m3 standard IS0 vessels, for various particle sizes (From
Bartknecht, 7978).