Page 674 - Dust Explosions in the Process Industries

Research and Development 64 7

The values are similar to those of natural organic materials. The results confirmthat dilute
clouds of dusts of explosives do not exhibit explosiveproperties but behave as clouds of
ordinary combustibledusts. Similar conclusionswere drawn by Li, Wang, and Ou (1994),
who studied the dust explosion properties of dry “powder emulsion explosive” powders.
Matsuda (1996) measured the minimum ignition temperature and explosion violence
properties of clouds of magnesium and various magnesium alloys in air and carbon
dioxide. The magnesium dust tested did not ignite (10 k.T pyrotechnical ignitor) when
dispersed in nitrogen.
Pegg and Amyotte (1996) and Pegg et al. (1997) determined the ignitability and
explosibility characteristics of some azide-based powders used as gas generants. None
of the powders tested represents a severe dust explosionhazard. Soundararajan,Amyotte,
and Pegg (1996) investigated the explosibility characteristics of iron sulphide dusts as
a function of particle size.
In anexperimental investigation, Gieras and Wolanski (1998) determined the constant-
volume explosion behavior (maximum pressure and maximum rate of pressure rise) of
clouds off rare eauth metal dusts in atmospheres of mixtures of nitrogen and water vapor.
Jong et al. (1999) gave a useful review of methods for determining the “flowability”
properties of powders at large, including two methods for determining the dispersibil-
ity of powders (see also Section 7.4.2 in Chapter 7).
Conde-Lazaro and Carcia-Torrent (1998,2000) studied experimentallythe influence
of high initialpressures, up to 15bar(abs), on constant volume maximum explosion pres-
sures and rates of pressure rise. For the dusts tested, the maximum explosion pressure
was approximatelyproportionalto the initial pressure. The relationshipbetween the ini-
tial pressure and maximum rate of pressure rise was less straightforward,with the tur-
bulence of the dust cloud playing a main role (see Section 1.3.8 in Chapter 1).
Lucas (20013 investigated the ignitability and explosibility characteristics of dusts
produced at very low pressures (vacuum) during the growing of single silicon crystals.
These dusts are very reactive and can present a significant dust explosion hazard when
brought in contact with air at atmospheric pressure. However, by controlled flushing of
the dusts with air?controlled surfaceoxidationof the particles is obtained,which reduces
the dust explosion hazard.
Nifiiku et al. (2002) investigated the ignitability and explosibility of dusts gener-
ated in processes for recycling electrical appliances. Dusts of polyurethane and other
plastics produced in shredding processes were subjected to a comprehensive testing
program. Amyotte et al. (2003) determined the minimum ignition temperatures of
s of iron sulfide particles in the BAM furnace.

PLOSIQN STATISTICS AND CASE HISTORIES

This section adds to the case histories described in Chapter 2 of this book.
eck and Jeske (1996) presented statistical data for recorded dust explosions in the
German process industries by BIA up to 1995. Sugar dust explosions in Germany are
treated specifically in a separate section of the paper. This includes a detailed analysis
of a major sugar dust explosion in a sieving plant. Schoeff (1999a) reviewed the dust
explosions that occurred in the U.S. grain, feed, and flour industries over the years,