Page 482 - Dust Explosions in the Process Industries

Sizing of Dust Explosion Vents 449

Figure 6.18 Maize starch explosion in a 5.8 m3 experimental bag filter unit in Norway. Vent area is
0.16 m2. Static opening pressure of the vent cover is 0. IO bar(g). Maximum explosion pressure is 0.15
bar(@. For a much clearer picture, see Color Plate 8.

0.5

0.4
- -
0.3
L
.n
;
0.2
Q Figure 6.19 Results from vented peat dust
explosions in a 5.8 m3 filter at P,,,, = 0.1 bar(g).
0.1 Comparison is made with VDI 3673 (7 979 edi-
tion) and vent sizing method used in Norway
01 I I I I I I J (Eckhoff, 1988). Injected dust concentration is
0 0.2 0.4 0.6 600 g/m3; = dust section of filter; o = clean
VENT AREA [dl section of filter (from Eckhoff, 1990).

dusts were used: maize starch and peat dust, both having K,, = 115 bar m/s, and polypro-
pylene and silicon dusts, both having K,, = 125 bar m/s. Considerable effort was made to
identify worst-case conditions of dust concentration and ignition timing. At these con-
ditions, experimental correlations of the vent area and Pd were determined for each dust.
As shown in Figure 6.19, the peat dust gave significantly lower explosion pressures
than those predicted by VDI 3673 (1979), even if the predictions were based on the
volume of the dusty filter section (3.8 m3> only.