(403g) Influence of [Alpha]-Zrp Particle Size and Crystalline Level On Dust Explosion Suppression Effectiveness

We introduce the use of zirconium phosphate (Zr(HPO₄)₂·H₂O, α-ZrP) crystals as a dust explosion suppressant. The influence of size and crystallinity of the crystals during a dust explosion was systematically studied. During α-ZrP synthesis, the size and crystallinity of the pristine platelets were tailored by adjusting the phosphoric acid (H₃PO₄) concentration and the reaction time [1, 2]. The thermal stability of the mixtures containing corn starch and ZrP crystals at different size and crystallinity was evaluated using thermo gravimetric analysis (TGA) and differential scanning calorimeter (DSC). In addition, the maximum pressure (P_max) and the maximum pressure rise ((dP/dt)_max) of these mixtures were obtained by performing dust explosion tests using a 36 L vessel. As a reference, monoammonium phosphate (NH₄H₂PO₄, MAP) was utilized. MAP is a widely studied compound commonly used as an explosion suppressant [3, 4]. From experiments, TGA revealed a higher thermal stability of mixtures containing corn starch and α-ZrP, in comparison with mixtures of corn and MAP. The DSC results confirmed that α-ZrP crystals of small size and low crystalline level possess the ability to absorb a great amount of energy during the corn starch decomposition. Finally, dust explosion tests of the mixtures confirm a reduction of P_max and ((dP/dt)_max). In general, a significant improvement of the suppression effectiveness was observed by reducing the α-ZrP size and crystallinity. We expect that the results from this study can be used as guidance on the synthesis of more efficient suppressant materials for dust handling industries with dust explosions hazards.  

 

References

 1. Clearfield, A., R.H. Blessing, and J.A. Stynes, New crystalline phases of zirconium phosphate possessing ion-exchange properties. Journal of Inorganic and Nuclear Chemistry, 1968. 30(8): p. 2249-2258.

2.  Sun, L., et al., Preparation of [small alpha]-zirconium phosphate nanoplatelets with wide variations in aspect ratios. New Journal of Chemistry, 2007. 31(1): p. 39-43.

3. Chatrathi, K. and J. Going, Dust deflagration extinction. Process Safety Progress, 2000. 19(3): p. 146-153.

4. Liu, Q., et al., Methane/coal dust/air explosions and their suppression by solid particle suppressing agents in a large-scale experimental tube. Journal of Loss Prevention in the Process Industries, 2011.