Dust explosion propagation in small diameter pipes

Abstract

In facilities handling combustible dusts, the isolation of propagating deflagrations requires great attention due to the potential catastrophic consequences of secondary dust explosions. While the ability of dust explosions to propagate is widely recognized, some misconceptions still exist. One of the common myths is that a dust explosion cannot propagate through small diameter pipes and that explosion isolation may not be required in that case. This article first presents a simplified theory of flame propagation in pipes. Dust explosion experiments performed in industrial-scale pipes smaller or equal to 4 in (or 100 mm) in diameter are then reviewed. The findings of the experiments are interpreted in the light of the simplified theory. Our study reveals that dust explosion propagation has been consistently observed in pipes with a diameter as small as 1 in. While the likelihood of flame propagation seems to decrease with pipe diameter and other “chemical” and “engineering” factors, it remains a realistic scenario and therefore should be addressed in the design and operation of powder handling systems.