混合金属粉尘爆炸最小点火能量影响因素研究

Research on influencing factors of minimum ignition energy for mixed metal dust explosion

为探究混合金属粉尘爆炸危险性及与单一粉体爆炸特性差异,确保车间安全生产,采用粉尘云点火能量测试系统对车间混合金属粉尘及铝粉最小点火能量在不同影响因素下的变化规律及2种粉尘火焰变化特征进行测试。研究结果表明:混合金属粉尘和铝粉最小点火能量在一定范围内(38~96μm)与粒径呈正相关性,当混合金属粉尘粒径大于75μm时,所需最小点火能量大于1000 mJ,其爆炸敏感性迅速降低,此时铝粉仍有较强爆炸敏感性;2种粉尘最小点火能量随质量浓度增加呈先降低后升高的趋势,最小点火能分别为295,15 mJ,对应的敏感质量浓度为600,1000 g/m3,混合金属粉尘在质量浓度为500~700 g/m3时具有较大爆炸危险性;同铝粉相比,混合金属粉尘点火能量更高、火焰燃烧时间更短、火焰高度更低、爆炸剧烈程度更弱。

In order to explore the explosive risk of mixed metal dust and the difference in explosive characteristics between it and single dust,and to ensure the work safety in the workshop,the dust cloud ignition energy testing system was used to test the changing rules of the minimum ignition energy of mixed metal dust and aluminum powder in the workshop under different influencing factors,as well as the flame change characteristics of two types of dust.The results showed that the minimum ignition energy of mixed metal dust and aluminum powder was positively correlated with the particle size within a certain range(38~96μm).When the particle size of mixed metal dust was greater than 75μm,the required minimum ignition energy was greater than 1000 mJ,and its explosion sensitivity decreased rapidly,while the aluminum powder still had stronger explosion sensitivity.The minimum ignition energy of two types of dust decreased first and then increased with the increase of mass concentration.The minimum ignition energy was 295 mJ and 15 mJ respectively,the corresponding sensitive mass concentration was 600 g/m3 and 1000 g/m3 respectively,and the mixed metal dust had greater explosion risk when the mass concentration was in the range of 500-700 g/m3.Compared with aluminum powder,the mixed metal dust had higher ignition energy,shorter flame burning time,lower flame height,and weaker explosion intensity.