Explosion characteristics and suppression evaluation of hydrogen mixed with low-concentration aluminum powder

To ensure the safety of the Al powder/H 2 hybrid system in industrial production, the variation law of H 2 explosion parameters under the environment of Al powder with a concentration of 0–150 g/m 3 was investigated in the confined container, and feasible hybrid explosion suppression approaches were explored. The results show that with the increasing concentration of Al powder , the explosion intensity of the hybrid systems exhibited an enhancing trend in all cases. The explosion hazard of the hybrid system was most severe when the concentration of H 2 reached stoichiometry . At 30 % H 2 and 150 g/m 3 of Al powder, the maximum explosion pressure ( P max ) of the hybrid system was almost 2.4 times compared to the pure 30 % H 2 explosion. CO 2 -driven silica/sodium phytate (SiO 2 /PA-Na) suppressed explosions more effectively than N 2 -driven SiO 2 /PA-Na. As the mass fraction of SiO 2 /PA-Na was increased to 50 wt%, the CO 2 -driven solid inhibitors decreased the P max and deflagration index ( K st ) of the hybrid system by 60.9 % and 90.1 %, respectively, and the delay of the time to peak explosion pressure ( T p ) was elevated to 306.4 %. Furthermore, it was revealed that the multi-component inhibitors suppressed the Al powder/H 2 hybrid explosion mainly through comprehensive effects such as adsorption of heat , dilution of oxygen, disruption of chain reactions, and isolation reactants. This study contributes to the enrichment of experimental evidence of Al powder/H 2 hybrid explosion and the precise development of efficient explosion prevention technology.