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

Study on explosion suppression of coal dust with different particle size by shell powder and NaHCO3

Investigation on thermokinetic suppression of ammonium polyphosphate on sucrose dust deflagration: Based on flame propagation, thermal decomposition and residue analysis

Characteristics of coal dust deflagration under the atmosphere of methane and their inhibition by coal ash

Huiwei Zhu

Papers

Inhibition of diammonium phosphate on the wheat dust explosion

Suppression characteristics and mechanisms of ABC powder on methane/coal dust compound deflagration

Syngas production by methane-rich combustion in a divergent burner of porous media

Improvement of hollow cylinders on the conversion of coal mine methane to hydrogen in packed bed burner

Flame propagation characteristics of mixed pulverized coal at the atmosphere of gasification