(188a) Dust Explosion Propagation and Isolation

Industrial processes handling combustible dusts usually comprise numerous pieces of equipment, such as grinders, mixers, dryers, classifiers, dust collectors, and storage hoppers, interconnected by a more or less complex network of pipes and conveying systems.

If a combustible dust cloud is accidentally ignited in a process enclosure, large amounts of heat and high pressures are generated in milliseconds. The resulting dust deflagration may, or may not compromise its structural integrity depending if the vessel is adequately protected or not. Nevertheless, the deflagration pressure will push the fireball through any existing openings, including process interconnections. The flame front will stretch and speed up due to increased turbulence, accentuating the severity of the initial event. Ultimately, a more violent secondary deflagration can take place when the flame reaches the next process enclosure, such that existing protection measures may well fail under these aggravated conditions.

This presentation will review the basic mechanisms of dust explosion propagation, unravel common myths about dust explosion propagation in process pipes and conveying systems, and provide detailed information on how to protect a process against dust explosion propagation.