Study on the inhibition of hydrogen explosion using gas-solid two-phase inhibitors

Hydrogen, as a renewable energy source, is widely used in energy supply and industrial production. However, due to frequent hydrogen explosion accidents posing significant threats to people and property, exploring effective inhibition methods and mechanisms becomes crucial. This study employs a 20L spherical device to evaluate the inhibitory effects of different inert gases (such as N₂ and CO₂) combined with various inert powders (including SiO₂, NH₄H₂PO₄, and NaH₂PO₄) as two-phase inhibitors on hydrogen explosions. The results show that single-phase CO₂ outperforms N₂ in explosion suppression, achieving complete prevention of hydrogen explosions at a 60% CO₂ concentration. N₂ shows minimal inhibition at concentrations below 40%, and even at 60%, it fails to provide complete inhibition. Two-phase inhibitors significantly enhance the inhibitory effects of inert gases, and reduce their required amounts. Both under N₂ and CO₂ conditions, the effectiveness of inhibitors is ranked as follows: NH₄H₂PO₄ > SiO₂ > NaH₂PO₄, with NH₄H₂PO₄ exhibiting excellent inhibitory capabilities. Mechanistic analysis, conducted using HSC and CHEMKIN molecular dynamics software, reveals that the basic reaction H + O₂ = O + OH possesses the highest sensitivity coefficient in hydrogen combustion, underscoring its vital function in elevating explosion temperatures. Adding NH₄H₂PO₄ lowers the maximum combustion temperature of hydrogen and prolongs the time required to reach this temperature. The primary function of NH₄H₂PO₄ is to lower the levels of H and O radicals by creating NH₃ intermediates and merging them with O and H atoms, which in turn diminishes the intensity of the reaction and effectively inhibits explosions.