The extinguishing performance of three dry chemical powders (DCPs) was investigated through a lab‐scale suppression system for liquefied petroleum gas (LPG) fire. The magnesium hydroxide (Mg(OH)₂), sodium bicarbonate (NaHCO3), and commercial ABC − MAP powders are used to prepare two groups of samples: raw samples and milled samples. The effect of milling action on the properties of DCPs, such as the bulk density, microstructure, particle size, thermal decomposition, and the extinguishing performance, is analyzed. The density test revealed that the bulk density increased after milling, and the Mg(OH)₂ had a lower density than the other powders. The microstructure analysis showed that the milled powders had a smaller particle size and more regular shapes than raw powders. The thermal analysis demonstrated that the powder decomposition process was somewhat similar with a slight difference in initial decomposition temperature and degradation rate. The fire tests proved that the extinguishing efficacy greatly improved after the samples were milled. Moreover, the experiments indicated that the milled Mg(OH)₂ was superior in fire extinguishing to the other samples with shorter extinction time and less agent quantity consumed. Based on the results, it can be inferred that the milling action has a significant influence in enhancing the extinguishing mechanisms' efficiency of DCPs.

中文翻译：

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三种化学粉在制粉前后的液化石油气灭火性能实验评估

通过实验室规模的液化石油气（LPG）灭火系统，研究了三种干粉化学灭火剂（DCP）的灭火性能。氢氧化镁（Mg（OH）₂），碳酸氢钠（NaHCO3）和市售ABC-MAP粉用于制备两组样品：原始样品和研磨样品。分析了铣削作用对DCPs性能的影响，如堆积密度，微观结构，粒度，热分解和灭火性能。密度测试表明，研磨后堆积密度增加，Mg（OH）₂具有比其他粉末更低的密度。显微组织分析表明，与原始粉末相比，研磨后的粉末具有更小的粒度和更规则的形状。热分析表明，粉末分解过程有些相似，但初始分解温度和降解速率略有不同。防火测试证明，研磨样品后，灭火效果大大提高。此外，实验表明，研磨后的Mg（OH）₂在灭火方面优于其他样品，具有更短的消光时间和更少的药剂消耗。从结果可以推断，铣削作用对于增强DCP的灭火机理的效率具有重要影响。