In order to prevent and control the deflagration hazard of magnesium powder in fuel-lean conditions, the explosion suppression experiment device was used to test the effect of solid inerting agents (Mg(OH)₂, Ca(OH)₂, Ca(HCO₃)₂) on the explosion characteristics of magnesium powder. The particle size and concentration were considered. The results show that within the particle size range from 17 to 74 μm, the maximum explosion pressure of magnesium powder decreases with increasing particle size, and rises first and then falls as powder concentration increases. For the 17.0 μm magnesium powder, the optimal explosion concentration and the maximum explosion pressure are 350 g/m³ and 0.716 MPa, respectively. The addition of three inerting agents, namely Mg(OH)₂, Ca(OH)₂, and Ca(HCO₃)₂, both reduces the maximum explosion pressure and the maximum pressure rise rate of magnesium powder. The inerting ratios for effective and complete inerting of magnesium powder by the three agents were obtained. Among them, Mg(OH)₂ exhibits the best inerting performance, with the inerting ratios of 170% and 220% for effective and complete inerting, respectively. The inerting mechanism of solid inerting agents on magnesium powder under fuel-lean conditions is revealed. Mg(OH)₂ decomposes upon heating to produce MgO, which adsorbs onto the surface of magnesium particles and prevents the contact between magnesium and oxygen, thereby achieving inerting; Ca(OH)₂ exerts an inerting effect merely through thermal decomposition; Ca(HCO₃)₂ generates CO₂ by thermal decomposition, which further enhances the inerting performance. The obtained conclusions provide an important reference for realizing the effective inerting of magnesium powder explosion under fuel-lean conditions.

In order to ensure the safe transportation and storage of highly flammable and combustible gases, it is essential to implement effective prevention and control measures. Explosion venting is an effective way to prevent and control its explosion hazards. In order to improve the efficiency and safety of explosion venting means and to promote the further study of secondary explosion in the external flow field of explosion venting, the research status of combustible gas explosion and explosion venting at home and abroad is analyzed, and meanwhile, the theory and achievements of combustible gas explosion venting in recent 20 years are summarized. Existing researches have shown that the explosion characteristics of combustible gases has been studied systematically, providing underpinning data for the study of combustible gas venting characteristics. A comprehensive examination of the explosion parameters and flame development alterations was performed in the internal and external flow fields resulting from deflagration. The hazard of deflagration was found to be exacerbated by the coupling between pressure waves and flame waves in the internal and external flow fields. The effectiveness of deflagration was evaluated based on the results of the study. It is difficult to define the initiation of the secondary explosion because the secondary explosion in the vent outflow field is limited by the poorly recognized evolutionary mechanism of blast-flame coupling. A preliminary study of the effect of the secondary explosion on the variation of the deflagration parameters has been carried out. In the explosion venting research, it is still necessary to narrow the span of influencing factors in the experimental aspect and improve the explosion venting equipment. In the numerical simulation research, it is necessary to carry out the study of complex models, the prediction of explosion venting hazards and the evaluation of the effect of explosion venting, which still need a lot of data and good models. Accordingly, the safe transportation and storage of flammable gases can be realized and the applications of flammable gases can be broadened.