Experimental study on the suppression of gas explosion using the gas–solid suppressant of CO2/ABC powder

•Effect of gas–solid suppressant of CO2/ABC powder on gas explosion was studied.•Explosion mitigation is influenced by the concentration of ABC powder and CO2.•Experiment results indicate that cooperative synergism exists between ABC powder and CO2.•The combination of ABC powder and CO2 has a better effect than each of the two components acting alone.

Gas explosion is the leading accident in underground coal mining in China. Using the self-improved 20 L spherical experimental system, the impacts of 8% CO2, ABC powder at various concentrations and mixture of them on the suppression of mine gas explosion were investigated. The results indicate that cooperative synergism exists between ABC powder and CO2. Their combination has a better effect than each of the two components acting alone, especially for the gas of larger concentration. When 0.25 g/L ABC powder was mixed with 8% CO2, the explosion limits were reduced by about 55%, the time to reach the peak explosion pressure was prolonged 3.56 times on average. Meanwhile, the maximum explosion pressure declined on an average of 59.4% and the maximum explosion overpressure rising rate decreased on an average of 91.1%. A combination of 0.20 g/L ABC powder and 8% CO2 completely suppressed 11% gas explosion. The explosion suppression mechanism of CO2 and ABC powder were probed theoretically. CO2 plays a key part in the whole explosion processes, and it can effectively suppress the forward reaction between gas and oxygen. While it is during the middle-later period of explosion processes that ABC powder plays a critical role. The particles decomposed from heated ABC powder such as nitrogen and phosphor will react with free radicals rapidly. Besides, atoms as N, P are capable of participating in chain reaction and reacting with active groups, significantly suppressing the gas explosion.