Zhao JiangPing, Tang GongFan, Wang YaChao, Han Yujiu
School of Resource Engineering, Xi'an University of Architecture & Technology, Xi'an, 710055, PR China.
Heliyon. 2020 Mar 4;6(3):e03457. doi: 10.1016/j.heliyon.2020.e03457. eCollection 2020 Mar.
The effect of particle size on the combustion and explosion properties of grain dust is investigated by Hartmann tube, cone calorimeter (CC), and thermogravimetry (TG), it aims to provide fundamental experimental data of grain dust for an in-depth study on its potential risk. The fine-grain dust facilitates the decrease in the minimum ignition temperature (MIT) of dust layer and dust cloud, as well as the obvious increases in the maximum explosion pressure (climbs from 0.36 to 0.49 MPa) and pressure rising rate d/dt (rises from 6.05 to 12.12 MPa s), leading to the increases in maximum combustion rate () and combustion characteristic index , corresponding to the greater or severer potential risk. Because the corresponding to combustion increases from 106.05 (sample with a particle size of 180-1250 μm) to 153.45 kJ mol for the sample of 80-96 μm, the combustion process gradually transforms from diffusion-controlled into a kinetically controlled mode with the decreasing particle size of grain dust, together with the retardation of initially transient charring. It determines that the competition between the charring and combustion dominates the decomposition, and the combustion prevails for the coarse particle, while the charring controls the combustion for the fine-grain dust.
通过哈特曼管、锥形量热仪（CC）和热重分析法（TG）研究了粒度对谷物粉尘燃烧和爆炸特性的影响，旨在为深入研究其潜在风险提供谷物粉尘的基础实验数据。细颗粒粉尘有助于降低粉尘层和粉尘云的最低着火温度（MIT），同时最大爆炸压力明显增加（从0.36MPa升至0.49MPa），压力上升速率dP/dt增大（从6.05MPa/s升至12.12MPa/s），导致最大燃烧速率（）和燃烧特性指数增大，这意味着潜在风险更大或更严重。由于对于粒径为80 - 96μm的样品，对应燃烧的从粒径为180 - 1250μm样品的106.05kJ/mol增加到153.45kJ/mol，随着谷物粉尘粒径减小，燃烧过程逐渐从扩散控制转变为动力学控制模式，同时初始瞬态炭化延迟。这表明炭化和燃烧之间的竞争主导了分解过程，对于粗颗粒，燃烧占主导，而对于细颗粒粉尘，炭化控制燃烧。
