Experimental study of NaHCO3/modified vermiculite composite powder for methane explosion suppression

Using a self-constructed experimental platform with 9.5 % methane as the explosive gas, the effects of various masses of NaHCO3, vermiculite, and NaHCO3/modified vermiculite composite powders on the explosion pressure, flame propagation shape, and flame propagation velocity of methane were investigated. The composite powders' thermal stability and surface microstructure were examined, along with the mechanism of explosion suppression, using thermogravimetric analysis, XRD analysis, and particle size analysis. By comparing various data, 50 wt% NaHCO3/modified vermiculite composite powder with a mass of 360 mg showed the best detonation suppression effect, with Pmax and (dP/dt)max reduced by 53.3 % and 87.1 %, respectively, and Pmax arrival time extended by 142.9 %. The flame disappearance time reached 467 ms, which increased by 165.3 %, and the maximum flame propagation speed decreased by 40 %. Methane explosion suppression is achieved by adding NaHCO3/modified vermiculite composite powder, which prevents flame propagation and breaks the methane explosion chain reaction by chemical and physical suppression of methane explosion.