可燃粉尘爆炸基础研究综述

Review of the basic researches on combustible dust explosions

对工业可燃粉尘爆炸基础研究进行了综述。对粉尘爆炸领域有史以来的主要基础研究成果进行了高度概括,内容涉及引起粉尘爆炸的可燃物质、影响粉尘云可燃性和爆炸性的因素、粉尘云在空气中的燃烧、引发粉尘爆炸的点火源、一次和二次粉尘爆炸、粉尘闪燃、杂混物的爆炸及粉尘云爆轰8个方面。回顾了粉尘爆炸的预防和缓解措施进展,指出了本质安全设计的意义。最后针对纳米颗粒粉尘的爆炸特性进行了探讨,通常粉尘的最小点火能随粉尘粒径减小而减小、爆炸指数随粉尘粒径减小而增大,这种趋势直到粉尘粒径减小到1~10μm一直存在,但这种趋势可能不会持续到纳米粉体级别,可能的两个原因是纳米粉体的难于分散和凝并作用。

This is a review paper on dust explosion research and its prevention and mitigation. First,this study reviews some specific issues on dust explosions in process industries,including materials that can give dust explosions,factors influencing ignitability and explosibility of dust clouds,combustion of dust clouds in the air,ignition sources that can initiate dust explosions,primary and secondary dust explosions,dust flash fires,explosions of "hybrid mixtures",the detonation of dust clouds. Then measures for dust explosion prevention and mitigation are reviewed,and inherently safer process design is addressed for its meaningful use in avoiding combustible dust cloud. Partial inertizing offers a new possibility for applying mitigatory measures such as explosion venting or automatic explosion suppression in situations where the explosion violence of the dust in the air only is too severe to permit the use of such techniques. The last paper section specifically addresses researches on explosions of nm-particle dust clouds. The minimum ignition energy (MIE) of most combustible μm powders/dust drop steadily and explosion index (Kst) values increase steadily with decreasing particle size in the range 1-10 μm. However,this trend may not continue right down to the range of nm particles due to two possible reasons:the limited dispersibility of nm-particle powders and the very high coagulation rates of nano-size particles. Despite extensive research and development for more than 100 years to prevent and mitigate dust explosions in the process industries,research remains to be done in all the areas mentioned/discussed in this paper,especially inherently safer process design methods for preventing explosible dust cloud formation and ignition sources occurring.