Page 218 - Dust Explosions in the Process Industries

190 Dust Explosions in the Process Industries

Pf2ffle (1987)reported on a dust explosion in the silo storage system of a pulverized coal
powder plant in Diisseldorf, Federal Republic of Germany, in July 1985. The explosion
occurred early in the morning in a 72 m3coal dust silo. The silo ruptured and burning mate-
rial thrown into the surroundings initiated a major fire, which was extinguished by water.
Fortunately, no persons were killed or injured in this primary accident. However, during
the subsequent cleaning-up process, a worker was asked to free the damaged silo of ashes
by hosing it down with water. It then appeared that a glowing fire had developed in the dust
deposit covered by the ashes. The worker had been warned against applying the water jet
directly to the smoldering fire, but for some reason he nevertheless did this. The result was
an intense dust flame that afflicted him with serious third degree bums. The smoldering
fire was subsequentlyextinguishedby covering its surface with mineral wool mats and sub-
sequently soaking the whole system with water containing surface-active agent.

2.1 1
DUST EXPLOSION IN A SILICON POWDER GRINDING
PLANT AT BREMANGER, NORWAY, IN 1972

In this serious explosion accident, five workers lost their lives and four were severely
injured. The explosion, which occurred in the milling section of the plant, was exten-
sive, rupturing or buckling most of the process equipment and blowing out practically
all the wall panels of the factory building. Figure 2.26 is a flowchart of the plant.

REFINED SILICON POWDER
(4mrn) FROM WET-CLASSIFIER VIBRATION

4 SILOS

PACKING

Figure 2.26 The dry part ofthe plant for production ofrefined silicon products at Bremangel; Norway
The grinding plant that was totally damaged in the explosion in 1972 is shown to the right in the chart.