An investigation on the aluminum dustexplosion suppression efficiency and mechanism of a NaHCO3/DE composite powder

Abstract

A NaHCO3/diatomaceous earth (DE) composite powder suppressant with unique clustered structures is prepared by high-pressure impact method, using DE as the carrier and NaHCO3 as the loaded chemical suppressant. The purpose is to obtain affordable, environmentally friendly, high-efficiency power explosion suppression materials. The suppression efficiencies of the NaHCO3/DE composite powder suppressant on aluminum dust propagation and explosion pressure are tested. The results show that as the content of the NaHCO3/DE composite powder suppressant increases, the maximum flame length gradually reduces and the suppression efficiency gradually increases. Addition of 60 wt% of the NaHCO3/DE composite powder suppressant suppress aluminum dust flame propagation and addition of 100 wt% of the NaHCO3/DE composite powder suppressant can fully suppress aluminum dust explosion. Comparison with pure NaHCO3 and pure DE reveals that NaHCO3/DE composite powder suppressant is more effective in suppressing aluminum dust flame propagation and aluminum dust explosion pressure than either of the two powders alone. The suppression mechanism of the NaHCO3/DE composite powder suppressant is established: On the one hand, reaction is suppressed by the decomposition of NaHCO3 and the product of this decomposition; on the other hand, as DE is rich in porous structures, when the loaded NaHCO3 powder separates from DE, the porous structures will not only limit flame propagation, but will also well adsorb the substances generated from explosion reaction.