超细聚苯乙烯微球粉体的燃爆特性研究

为研究超细聚苯乙烯微球粉体的燃爆特性,通过粉尘层最低着火温度测试装置、MIE-D1.2最小点火能测试装置、20 L球形爆炸测试装置,对其最低着火温度、最大爆炸压力、最小点火能量(MIE)等爆炸特性参数进行测定,探讨了加热温度、点火延滞时间、粉尘质量浓度、粉尘粒径对粉体燃爆特性的影响。结果表明:超细聚苯乙烯微球粉尘层在350℃左右时会发生无焰燃烧,且加热温度越高,粉体粒径越小,粉尘层发生着火时所需的时间越短;当粉体质量浓度为250 g/m3时,最大爆炸压力达到0.65 MPa,质量浓度为500 g/m3时,最大爆炸压力的上升速率达90 MPa/s以上;随点火延滞时间增加,最小点火能表现出先缓慢减小再急剧增大的规律;随粉尘质量浓度增加,最小点火能逐渐降低,当粉尘质量浓度超过500g/m3后逐渐趋于稳定。

On the particular burst-out and explosion features of the superfine polystyrene microsphere powder

The given paper intends to report its experimental study results on the particular burst-out and explosion features of the superfine polystyrene microsphere powder,including the minimum ignition temperature (MIT),the maximum explosion pressure,the maximum rate of pressure increase,the minimum ignition energy(MIE) and some other indexes through a series of experimental devices,i.e.the minimum ignition temperature test device,the 20 L spherical dust explosion test device and the MIE-D1.2 test device.At the same time,we have also made a discussion over the influences of the heating temperature,the ignition delay time,the dust concentration,and the powder size on the dust explosion features.The results of our study and experiments show that it is possible to trace and observe the flameless combustion of superfine polystyrene microsphere powder even at a high temperature about 350 ℃,with the combustion starting time of the dust layer going on at higher heating temperatures with the smaller powder particles bursting on.When the dust concentration is as high as 250 g/m3,the maximum explosion pressure can likely reach 0.65 MPa,with the maximum rate of pressure going to be over 90 MPa/s in 500 g/m3.What is more,the polystyrene microspheres with their diameter of 3 μm may tend to explode when the dust concentration reaches 25 g/m3,whereas the maximum explosion index reaches 24.245 MPa · m/s,all of which implies that it would be possible to attribute its dust explosion hazards to level St2 in terms of the dust explosion hazard categorization.Furthermore,with the increase of ignition delay time,the minimum ignition energy tends to decrease slowly at first,and,then,increases abruptly on the condition when the ignition delay time is beyond 70 ms.Under the condition of low dust concentration,the larger the particle size of polystyrene microsphere is,the wider the increasing amplitude of the minimum ignition energy will be.However,when the dust concentration exceeds 500 g/m3,the microsphere particle size begins to have little effect on the minimum ignition energy,and,in turn,it would tend to get stable.And,finally,the calculation results suggest that the micro-sized superfine polystyrene microsphere powders (particle sizes are 3 μm,5 μm,10 μm,20 μm)with the MIE characterized value data of 9.2 mJ,12.9 mJ,14.1 mJ,and21.6 mJ may turn to be very much sensitive to the electrostatic spark.