BC粉体抑爆剂改性及抑制甲烷/空气混合物爆炸

采用不同工艺和配方,对BC干粉进行细化和表面改性,制备了3种规格的碳酸氢钠抑爆粉体,应用扫描电镜及激光粒度测试仪表征其表面特性及粒径分布,结果表明:采用MM4及MT3工艺所制备的抑爆粉体,粒径得到大幅度降低,比表面积显著增大,表面特性得到改善。自主设计了主动式抑爆器并进行了参数优化,膜片开启压力为8 MPa,抑爆器在敞开空间冷态喷射实验表明:从药柱点火到抑爆剂完全喷射的时间为12 ms,抑爆粉体射流最大喷射速度可达5～15 m·s^-1。在容积为200 L的爆炸实验装置中,以化学当量比的甲烷-空气混合物爆炸为抑制对象,开展了细化改性抑爆粉体主动式抑爆的实验研究,研究表明:粉体抑爆效果不仅与平均粒径有关,同时粒径分布的影响也较为重要;粒径呈正态分布、表面形状不规则的粉体更有利于与爆炸火焰相互作用,抑爆效能得以提升,较常规BC粉体相比,抑爆粉体粒径细化到10 mm数量级时,抑爆性能提高8～10倍。

Modification of commercial BC dry chemical powder suppressant and experiments on suppression of methane-air explosion

Three kinds of superfine sodium bicarbonate explosion suppression powder were prepared from commercial BC dry powder with different process and surface modification. Scanning electron microscopy and laser particle analyzer were used to investigate the surface properties and particle size distributions. Preliminary suppression experiments on methane-air mixture explosion at chemical equivalent ratio were carried out with the prepared superfine sodium bicarbonate powder in 200 L chamber. The key physical parameters of the suppression powder such as particle size and distribution, surface area, and surface properties are improved significantly with two of the preparation processes. For the designed explosion suppressor with optimized parameters, the total spray time of the suppression powder is in the range of 12 ms and the maximum jet velocity can reach 5-15 m·s^-1 at the opening pressure of diaphragm of 8 MPa. The efficiency of explosion suppression is not only related to the average particle size, the particle size distribution is also important, and powder with irregular surface shape can suppress the explosion more effectively. Compared to the normally commercially available BC powder, the ability of explosion suppression is improved eight to ten times when the powder is refined to the order of magnitude of ten micrometers.