Abstract Reduction of dust explosion hazards can be achieved by processing materials in less hazardous forms. Two principles are often employed to moderate explosion potential. One approach is to increase dust particle size so as to decrease its reactivity. The other involves altering the dust composition by admixture with solid inertants. An essential prerequisite for dust explosions is the formation of airborne dust clouds. Dust dispersibility (i.e., the ease of dispersion of a dust and the tendency of the particulate matter to remain airborne once a dust cloud has been formed) is therefore an important safety characteristic, certainly requiring research attention. This paper presents experimental results using a modified Hartmann tube to determine the effect of admixed solid inertants on particle size distribution of dust clouds. Nine types of combustible dust and two sizes of inert Al2O3 were tested repeatedly five times. Generally, admixing small amounts of micro-sized solid inertants caused relative improvement on the dispersibility of combustible dust, forming a better dispersed cloud, and sometimes resulted in increased ignition sensitivity. However, the addition of agglomerate nano inert particles caused a multilayer coating of combustible particles, causing an increase in the effective surface area at the particle contact points, and thereby increasing cohesion in the powder mixtures. Higher inter-particle forces in turn enhanced the combustible particle agglomeration during dispersion, leading to an increase in effective particle size distribution.

中文翻译：

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混合固体惰性剂对改进型哈特曼管中可燃粉尘云分散性的影响

摘要 通过加工危害较小的材料可以减少粉尘爆炸的危害。通常采用两个原则来降低爆炸可能性。一种方法是增加粉尘粒径以降低其反应性。另一种是通过与固体惰性剂混合来改变粉尘成分。粉尘爆炸的一个必要先决条件是空气中粉尘云的形成。因此，粉尘分散性（即，粉尘易于分散，一旦形成粉尘云，颗粒物质易于留在空气中）是一项重要的安全特性，当然需要研究关注。本文介绍了使用改进的哈特曼管来确定混合固体惰性剂对尘埃云粒度分布的影响的实验结果。对九种可燃粉尘和两种尺寸的惰性氧化铝进行了五次重复测试。一般情况下，掺入少量微细固体惰性剂可使可燃粉尘的分散性相对提高，形成更好的分散云，有时会导致点火敏感性增加。然而，团聚纳米惰性颗粒的添加导致可燃颗粒的多层涂层，导致颗粒接触点处的有效表面积增加，从而增加粉末混合物的内聚力。更高的粒子间力反过来增强了分散过程中的可燃粒子团聚，导致有效粒度分布的增加。掺入少量微颗粒固体惰性剂，可相对改善可燃粉尘的分散性，形成更好的分散云，有时会导致点火敏感性增加。然而，团聚纳米惰性颗粒的添加导致可燃颗粒的多层涂层，导致颗粒接触点处的有效表面积增加，从而增加粉末混合物的内聚力。更高的粒子间力反过来增强了分散过程中的可燃粒子团聚，导致有效粒度分布的增加。掺入少量微颗粒固体惰性剂，可相对改善可燃粉尘的分散性，形成更好的分散云，有时会导致点火敏感性增加。然而，团聚纳米惰性颗粒的添加导致可燃颗粒的多层涂层，导致颗粒接触点处的有效表面积增加，从而增加粉末混合物的内聚力。更高的粒子间力反过来增强了分散过程中的可燃粒子团聚，导致有效粒度分布的增加。团聚纳米惰性粒子的添加导致可燃粒子的多层涂层，导致粒子接触点处的有效表面积增加，从而增加粉末混合物的内聚力。更高的粒子间力反过来增强了分散过程中的可燃粒子团聚，导致有效粒度分布的增加。团聚纳米惰性粒子的添加导致可燃粒子的多层涂层，导致粒子接触点处的有效表面积增加，从而增加粉末混合物的内聚力。更高的粒子间力反过来增强了分散过程中的可燃粒子团聚，导致有效粒度分布的增加。