The recent concept of inherent safety uses the properties of a material or process to eliminate or reduce the risk thus removing or minimizing the hazard at the source as opposed to accept the hazard and looking to mitigate the effects. In this framework the control of particle size in dust explosion prevention and mitigation is recognized as a major inherent safety methodology. Indeed, the increase of particle size may allow significant reduction of particle reaction rate eventually reducing the risk. 
 
In this paper a novel model is developed to quantify the effect of particle size on dust reactivity in an explosion phenomenon. The model takes into account all of the steps involved in a dust explosion: internal and external heating, devolatilization reaction and volatiles combustion. Varying the dust size can establish different regimes depending on the values of the characteristic time of each step and of several dimensionless numbers (Damkohler number, Da; Biot number, Bi; thermal Thiele number, Th). Results from the model are reported in terms of the deflagration index (KSt) as a function of dust diameter in all regimes and at varying Da, Th and Bi. Comparison with experimental data from polyethylene explosion tests shows promising results. Finally, the results of the model are presented in the form of a dust explosion regime diagram, which is helpful to make a draft evaluation of the role of dust size on explosion behavior and severity.

Modelling the effect of particle size on dust explosion

Effects of hydrogen and initial pressure on flame characteristics and explosion pressure of methane/hydrogen fuels

Suppression of wood dust explosion by ultrafine magnesium hydroxide

Flame inhibition of aluminum dust explosion by NaHCO3 and NH4H2PO4

Haipeng Jiang

Papers

Flame inhibition of aluminum dust explosion by NaHCO3 and NH4H2PO4

Inhibition of aluminum dust explosion by NaHCO3 with different particle size distributions.

Inhibition evaluation of ABC powder in aluminum dust explosion

Flame suppression mechanism of aluminum dust cloud by melamine cyanurate and melamine polyphosphate.

Suppression mechanism of ultrafine water mist containing phosphorus compounds in methane/coal dust explosions