Application of microencapsulated fibrous carrier inhibitors in suppressing flake aluminum dust explosion: Performance and mechanism

Flake aluminum powder (F-Al), due to its larger specific surface area and higher reactivity, posing a potential threat to the process safety of involved enterprises. To mitigate the explosion caused during the production of F-Al, a green composite inhibitor, Sep@CS@PA-Na, was successfully prepared in the aqueous phase using microencapsulation technology with sepiolite (Sep), chitosan (CS), and sodium phytate (PA-Na) as raw materials. The suppression of F-Al explosions in a vertical combustion duct system by inhibitors with different inerting ratios (alpha) was investigated. The results showed that after adding Sep@CS@PA-Na with an alpha of 0.75, the maximum flame propagation velocity (V-max), the average flame velocity (V-avg), and the velocity of the flame reaching the pipeline top (V-top) decreased by 79.6%, 75.1%, and 86.2%, respectively, and the reduction of the maximum flame front pressure (P-max) and the maximum flame pressure rise rate ((dP/dt)(max)) were 90.4% and 89.8%, respectively, and the peak temperature (T-p) dropped to 505 degrees C. Combined with TG-DSC and explosion product analysis, Sep@CS@PA-Na possessed both gas-phase reaction and surface reaction suppression functions, which were mainly reflected in the dilution effect, quenching effect, and barrier effect. This work will provide technical support for the emergency prevention and control of energetic metal dust explosions.