关键词: 钾盐粉体, 瓦斯爆炸, 爆炸超压, 超压衰减, 管网

Abstract:

To prevent and contain mine gas explosion accidents, the explosion suppression performance of potassium salt powders and their action laws in the pipe network were deeply explored. In a pipe network with parallel pipelines, branching pipelines, and angular connecting pipelines, an experimental study on the suppression of gas explosions by three potassium salt powders, namely KHCO₃, K₂C₂O₄, and KH₂PO₄, driven by N₂, was carried out. The pyrolysis characteristics of the powders were studied through thermogravimetric(TG) analysis. By combining explosion experiments, the overpressure changes were monitored. The explosion overpressure and overpressure attenuation coefficient under the action of potassium salt powder were explored. Moreover, the explosion suppression mechanism was analyzed with the assistance of the Chemkin-Pro simulation software. The results indicate that after the explosion suppression by the three powders, the superposition and attenuation process of the shock wave pressure is eliminated, and the overpressure time-history curve exhibits a "single peak value" characteristic. Among them, the KHCO₃ powder has the best suppression effect on the explosion overpressure peak value, with a decrease range of 83.2% - 88.9%. K₂C₂O₄ ranks second, and KH₂PO₄ is relatively weaker. The pressure attenuation degree in the oblique angular connecting branch pipe 4 is greater than that in other branch pipes. Both the branch pipe 4 and the turning section can leverage their own structural characteristics to enhance the overpressure attenuation effect, and they are regarded as preferred locations for installing explosive inhibitors. KHCO₃ is able to maximize the utilization of this structural characteristic to enhance the explosion suppression effect. Additionally, the shock wave overpressure attenuation coefficient K₂ of the branch pipeline section shows a situation where it is less than 1.This phenomenon is found to be exacerbated by the addition of K₂C₂O₄ and KH₂PO₄ powders. Through the analysis using the Chemkin-Pro simulation software, it is concluded that the free radical content under the KHCO₃ working condition is the lowest, and the explosion suppression effect is the best, followed by the K₂C₂O₄ working condition, and finally the KH₂PO₄ working condition.

Key words: potassium salt powder, gas explosion, explosion overpressure, overpressure attenuation, pipe network