Suppression Characteristics Of Gas/solid Two-phase Inhibitors On Methane Explosion

In the transportation and utilization of CH₄,explosion accidents often occur due to its flammable and explosive characteristics.In order to reduce the hazards caused by explosion accidents,it is important to study the suppression technology for the safe extraction,transportation and utilization of CH₄.In this paper,N₂ and CO₂ were selected as gas phase inhibitors,NaHCO₃,NH₄H₂PO₄ and red mud were used as powder inhibitors to study the maximum explosion pressure and flame propagation of 9.5%methane-air mixed gas explosion under the conditions of single-phase and two-phase inhibitors.Compared with the actual suppression effect and theoretical suppression effect of gas/solid two-phase inhibitors,analyzed the inhibition characteristic and inhibition mechanism of CH₄ explosion,and provide a theory for the development of inhibitors in active explosion suppression devices.Using a 5 L flammable gas explosion experimental device,the suppression effects on the CH₄ explosion of the single-phase and the gas/solid two-phase inhibitors were tested respectively.The results showed that the CO₂ had better suppression effect than N₂.The methane explosion was completely suppressed by 20%CO₂ or 32%N₂.The suppression effect of powders was:NaHCO₃>NH₄H₂PO₄>red mud,and the explosion was completely suppressed by 0.20 g/L NaHCO₃ or 0.32 g/L NH₄H₂PO₄.Gas/solid two-phase inhibitors had a better suppression effect on the explosion.Compared with single inhibitor,the explosion pressure curves tended to be gentle,and the maximum explosion pressure and its peak arrival time showed a significant decrease and delay,and the time of flame front reached the pipe exit significantly extended.The gas/solid two-phase inhibitors had the best ratio of inhibition on the explosion,at this time,the amounts of the inhibitors added were minimized,and the explosion could be completely suppressed.CO₂/NaHCO₃ two-phase inhibitors had the best suppression effect.Under different volume fractions of CO₂,when the two-phase inhibitors ratio were 4%CO₂/0.12 g/L NaHCO₃,8%CO₂/0.08 g/L NaHCO₃ and 12%CO₂/0.04 g/L NaHCO₃,the minimum amount of inhibitors were used and the explosion was completely suppressed.For different two-phase inhibitors,there was a difference between the actual suppression effect and the theoretical suppression effect.The actual suppression effect of CO₂/NaHCO₃ two-phase inhibitors and inert gas/red mud two-phase inhibitors was weaker than the theoretical suppression effect.For different characteristic parameters of N₂/NaHCO₃ two-phase inhibitors,there was a difference between the actual suppression effect and the theoretical effect.The actual suppression effect of inert gas/NH₄H₂PO₄two-phase inhibitors was better than the theoretical suppression effect.Finally,we discussed the suppression mechanism of gas/solid two-phase inhibitors.Based on the thermal reaction mechanism of the explosion and the chain reaction mechanism,and combined with the thermodynamic properties of the powders material,the suppression mechanism of the inhibitors was analyzed from the aspects of physical inhibition and chemical inhibition.