A novel ATH/SBA-15 suppressant prepared by in-situ synthesis and its inhibition mechanism on PE dust deflagration flame

Abstract

Recently, polyethylene (PE) dust explosions have become a serious threat to the petrochemical industry. In order to prevent the occurrence of PE dust explosion, a novel aluminum hydroxide (ATH)/Santa Barbara Amorphous type 15 (SBA-15) powder explosion suppressant with the uniform dispersion of ATH was prepared by in-situ synthesis method. For ATH/SBA-15 inhibitor, SBA-15 molecular sieve and ATH was used as the carrier and active component of explosion inhibition, respectively. The inhibition effect on PE dust deflagration was studied by flame propagation experiment. The results showed that when the addition amount of ATH/SBA-15 exceeded 40 wt%, PE dust deflagration flame was almost completely inhibited. Furthermore, the Coats-Redfern method was used to study the thermal decomposition kinetics model. It was found that the thermal decomposition kinetics model of PE before and after the addition of explosion suppressants followed the random nucleation and growth reaction mechanism (A3 model). Further fitting analysis showed the apparent activation energy of PE increased significantly after adding ATH/SBA-15 inhibitor, confirming that ATH/SBA-15 had a significant inhibitory effect on PE deflagration in thermodynamics. Finally, combining with a series of characterization results, it was founded that the ATH/SBA-15 suppressant played the efficient synergy of physics and chemistry, which was efficient in inhibiting PE deflagration. The physical inhibition mainly includes: the free radicals adsorption by SBA-15 molecular sieve, the coating effect of ATH, the endothermic effect and the reduction in O2 concentration by H2O decomposed from ATH. Meanwhile, the chemical inhibition mainly lies in the elimination of the free radicals O· and H· in the explosion process by ATH.