Abstract
Dust explosions in the process industries most often start inside process equipment such as mills, dryers, mixers, classifiers, conveyors, and storage silos and hoppers. For any given type of dust, the ease with which the dust cloud ignites, and the rate with which it burns, vary considerably as a function of parameters well known in powder science and technology. The most important are the primary particle size distribution of the dust, the degree of deagglomeration of the dust particles in the cloud, the dust concentration distribution in the cloud, and the cloud turbulence. The last three properties are entirely dependent on the actual process situation in which the dust cloud is generated. The paper discusses the influences of the four parameters on ignition sensitivity and explosibility, and on the design of mitigatory measures such as venting, isolation and automatic suppression. The role of powder science in understanding the development and propagation of secondary dust explosions is also outlined.
