Page 110 - Dust Explosions in the Process Industries

Dust Explosions: An Overview 83

the one that gives a strain of 2%. However, in the latter case, repair of deformed process
equipment must be foreseen, should an explosion occur.
If dust explosions in the plant of concern were fairly frequent events, one might con-
sider the use of the pressure vessel design approach, because the deformations that often
result with the pressure-shock-resistant design would be avoided. This is a matter of ana-
lyzing cost versus benefit. From the point of view of safety, the main concern is to pro-
tect personnel, that is, avoid the rupture of process equipment.
The field of structural response analysis has undergone substantial development over
the past decades. Finite element techniques are now available for calculating stress and
strain distributions on geometrically complex enclosure shapes, resulting from any given
internal overpressure. Two examples are shown in Figures 1.92 and 1.93.

Figure 1.92 Finite element design of a rotary lock
housing capable of withstanding 7 0 bar(g) inter-
nal pressure (Courtesy of T. Pinkwasser, Buhler,
Switzerland).

Figure 1.93 Section of finite element network of
cylindrical casing of a pneumatic unloaded tower,
with explosion vent opening. The diameter of the
tower is 2 m (Courtesy of T. Pinkwasser, Buhler,
Switzerland).