Abstract: In order to investigate the effect of plant ash (PA) on methane explosion, PA was modified and a small semi enclosed visual explosion experimental platform was built. By changing the powder mass and particle size, the influence of modified plant ash (MPA) powder on the peak overpressure, flame propagation speed, and flame propagation morphology of 9.5% methane explosion in explosion pipelines was studied. The explosion suppression mechanism was analyzed and discussed based on the characterization results. The results showed that MPA powder has a large specific surface area and porosity, and it has a high pyrolysis weight loss rate, with a mass loss of 46%. The particle size and mass of MPA powder with the best suppression performance on methane explosion propagation in pipelines obtained in the experiment were 64~73 μm and 300 mg, respectively. Compared with the non-spraying powder experimental group, it resulted in a maximum reduction of 50.14% in the maximum explosion overpressure and a maximum reduction of 51.17% in the maximum propagation rate of methane flame. It can be seen that MPA powder exhibits excellent explosion suppression performance against methane explosions.

Key words: methane explosion, plant ash, particle size distribution, explosion suppression mechanism, explosion overpressure, flame propagation speed