Flavio Parozzi* Libro, Chemical Engineering Transaction Volume 10 2006 * CESI RICERCA The paper presents an experimental research dedicated to the risk of formation of explosible clouds from typical thick dust deposits of coal within electric power generation plants. Representative samples of coal dust, collected over components and floors, were characterized in terms of density, burnable fraction, morphology and size distribution. The resuspension behavior was observed and quantified in a small-scale experimental facility where the dust samples were subjected to fully turbulent gas flows, within a plexiglass square duct. The gas, nitrogen, was injected at velocities ranging from 0 to 80 m/s. Over 80 experimental tests were carried out, obtaining repeatability and continuity of the results. The analysis of the experimental data indicates that the mobilization of dry coal dust is detectable at air speed higher than 6-7 m/s, and the mixing with air is not instantaneous, as the dust particles roll and jump before reaching the gas bulk. This behavior can create a flow zone, close to the surface of dust deposits, having a wide range of particle concentration that can fall within the explosibility range.