散粮装卸系统斗式提升机内粉尘爆炸特征参数

Explosion parameters of grain dust inside the bucket elevator for bulk handling system

针对散粮装卸系统斗式提升机机座中的粮食粉尘,在对其进行特性参数表征及热分解特性分析的基础上,开展了爆炸特征参数测试。结果表明,斗式提升机内粮食粉尘粒径在60~80μm的分布相对密集,中位粒径为75μm,粉尘颗粒呈不规则状,有机物占总质量的80%以上,因而具有一定的爆炸危险性。粮食粉尘的爆炸下限浓度为70g/m3,而特定条件下斗式提升机内的粉尘浓度明显高于该值,故存在较大的粉尘爆炸隐患,清扫积尘、防止产生可能的点火源是预防该类场所发生粉尘爆炸的有效手段。粉尘的最危险爆炸浓度为700g/m3,最大爆炸压力约为0.5 MPa,最大压力上升速率约为10 MPa/s,因而在实际生产中,必须采取相应的爆炸泄压或抑制措施。

Based on the analysis of surface characterization, size distribution and thermal decomposition, explosion parameters experiment was carried out for the grain dust inside bucket elevator of the bulk handling system. The results showed that the main particle was distributed in the range of 60 to 80 μm with 75 μm in median particle diameter for the grain dust,the surface shape was irregular and the organic matter accounted for more than 80% of the total mass,which had certain explosion hazard. The lower explosible limit was 70 g/m3 for the dust, the concentration of grain dust inside the bucket elevator at specific conditions was significantly higher than that, so the potential risk of dust explosion was existed, the preventive measures such as deposition dust cleaning,prevention of possible ignition source should be adopted. The most dangerous explosive concentration for the dust was 700 g/m3 with the maximum explosion pressure of 0.5 MPa and the maximum rate of pressure rise of 10 MPa/s, respectively, explosion venting or suppression must be taken fully into account in industrial processing.