不同粒径PMMA粉尘爆炸特性研究

Experimental Investigation on Explosion Characteristic of PMMA Dust with Different Particle Sizes

采用20L球形爆炸测试装置,对比研究了30μm、800 nm、100 nm的微纳米PMMA(聚甲基丙烯酸甲酯)粉尘的爆炸特性,得出纳米粉尘相比微米粉尘具有爆炸升压速率大、爆炸持续时间短的特性;在密闭容器内,100 nm和800 nm粉尘颗粒的最佳爆炸浓度为250 g/m^3,最大爆炸压力P_(max)分别0.821 MPa和0.865 MPa,爆炸指数K_(st)分别为27.3 MPa·m/s和25.8 MPa·m/s;30μm粉尘颗粒最佳爆炸浓度为750 g/m^3,最大爆炸压力0.708 MPa,爆炸指数K_(st)为10 MPa·m/s^1,总体上纳米粉尘的爆炸危害远大于微米粉尘,但由于粒径减小团聚效果增大,100 nm粉尘只在低浓度下(<250 g/m^3)的爆炸威力高于800 nm粒径,当浓度增大,团聚严重,其爆炸威力却低于800 nm粒径,所以对有机纳米粉尘并非粒径越小,爆炸威力越大,而更应关注纳米粉尘在低浓度下的爆炸危害,研究结论可为加工、储存有机纳米材料的安全防护与安全设计提供指导。

The explosion characteristic of poly methyl methacrylate （PMMA） dust with different particle sizes as 30μm, 800 nm and 100 nm were studied by using a 20 L spherical explosion test device in this paper. The results show that the optimized parameters for dust particles in a closed vessel are as follows. For 100 nm and 800 nm particles, the best concentration is 250 g · m^-3, the maximum pressure P is O. 821 and O. 865 MPa, the explosion index Kst, is 27.3 MPa· m· s^-1 and 25.8 MPa· m· s^-1. For 30 μm particles, the best concentration is 750 g · m^-3 , the maximum pressure Pmax is 0. 708 MPa and the explosion index Kst is 10 MPa · m· s^-1. Generally, the explosion hazard of nano - dust is more powerful than that of micro - dust. The explosion damage of dust of 100 nm is stronger than that of dust of 800 nm at lower concentrations （ 〈 250g · m^-3） only. However, it is weaker than that of dust of 800 nm with the concentration increasing due to the increased aggregation with particle size decreasing. It implies that it is not true that smaller organic nano - dust particles present stronger explosion damage. Additionally, hazard caused by the explosion of nano - dust at lower concentrations must be concerned. The conclusions of this paper are helpful for the safety design for the equipment processing organic nano- dust.