Experimental study on the effect of modified attapulgite powder with different outlet blockage ratios on methane-air explosion

Highlights: • The characterization characteristics of the powder were obtained. • The influence on pressure and flame propagation is analyzed. • The mechanism of explosion suppression and explosion venting is studied. Through visual explosion experiment platform, this study conducted comparative experiments on methane-air premixed gas with a methane volume fraction of 9.5 % under different working conditions. The experiment studied the effect of active explosion suppression (spraying modified attapulgite powder) and explosion venting (setting the outlet blockage ratios) on methane explosion. The results showed that when the amount of powder injection was constant, the outlet blockage ratios of the pipeline was positively correlated with the peak explosion overpressure and the explosion index, but was negatively correlated with the peak flame propagation velocity. When the outlet blockage ratio was constant, the amount of powder spraying was negatively correlated with the peak value of explosion overpressure and the peak value of flame propagation velocity. When the outlet blockage ratio was 0, the explosion precursor shock wave broke through the PVC plastic film, which made the influx of a large amount of fresh air promote the generation of turbulence in the pipeline, and a "tulip-shaped" flame front appeared. The combination of active explosion suppression and explosion venting showed different effects on the explosion overpressure and flame propagation characteristics of methane explosion. Finally, this study conducted an in-depth discussion on the complex mechanism contained in it.