Effects of particle size distribution on the explosion severity of coal dust

ABSTRACT

The effects of particle size distribution (PSD) on coal dust explosion severity were investigated using a 20 L vessel. The severity was evaluated by the maximum explosion pressure ($P_{\mathrm{e}x}$), the maximum rate of pressure rise ($(\mathrm{d}P/{\mathrm{d}\mathrm{t})}_{\mathrm{e}\mathrm{x}}$), and the time spans ($t_1$, $t_2$) between ignition and $P_{\mathrm{e}x}$ and between ignition and $(\mathrm{d}P/{\mathrm{d}\mathrm{t})}_{\mathrm{e}\mathrm{x}}$ during a trial. These parameters of five coal samples with the same particle size span (PSS) and different PSD were measured at 250 $\mathrm{g}/{\mathrm{m}}^3$. The results show that the explosion rate is greatly affected by PSD. When the finer particles account for 30 wt%, $(\mathrm{d}P/{\mathrm{d}\mathrm{t})}_{\mathrm{e}\mathrm{x}}$ increased significantly, whereas $t_1$ and $t_2$ values decreased. $(\mathrm{d}P/{\mathrm{d}\mathrm{t})}_{\mathrm{e}\mathrm{x}}$, $t_1$ and $t_2$ are affected significantly by $D_{10}$ and $D_{50}$ (the particle size for which 10% and 50% of the particles by projection area) dust components. It is suggested that $D_{10}$ and $D_{50}$ should be considered when polydispersity is used to describe the PSD. $D_{10}$, $D_{50}$, and the Specific Surface Area(SSA) are related to these explosion parameters and provide the better description of the PSD. The smaller the particle size is, the more complete the particles combust and the smaller the calorific values of dust explosion products are.

KEYWORDS:

• Coal dust explosion
• particle size distribution
• explosion pressure
• explosion rate
• explosion products calorific value

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Additional information

Notes on contributors

Jiangshi Zhang

Jiangshi Zhang is a professor in China University of Mining and Technology (Beijing), his main research direction is dust control and safety management.

Longhao Sun

Longhao Sun is a master student in China University of Mining and Technology (Beijing), his main research direction is dust explosion.

Fangchao Nie

Fangchao Nie is a master student in China University of Mining and Technology (Beijing), his main research direction is dust explosion.

Hejun Zhou

Hejun Zhou is a master student in China University of Mining and Technology (Beijing), his main research direction is dust control.