优选阻燃材料惰化锆粉云燃烧的效果和机理

Effects and mechanism of inerting zirconium dust cloud combustion with preferred flame retardant materials

为探索惰化锆粉云燃烧的机理,采用粉尘云最低着火温度测试系统及热重-差热同步热分析系统,对纯锆粉、单一阻燃材料与锆粉混合体系悬浮粉尘云状态下的最低着火温度进行研究,进而筛选出效果较好的阻燃材料,并分析其惰化机理。结果表明:0.2 g锆粉在喷尘压力为100 kPa、恒温时间为10 s条件下的最低着火温度为344℃。锆粉与单一阻燃材料混合体系悬浮粉尘云状态下的最低着火温度随阻燃材料添加量的增加而呈上升趋势,其中,ABC粉对混合体系悬浮粉尘云状态下的最低着火温度提升最为明显,在添加比为1∶1、1.5∶1、2∶1、3∶1时,最低着火温度分别提升了48.35%、81.31%、92.31%、97.8%。分析机理可知:锆粉样品中水分蒸发和ABC粉热分解吸热都会降低混合体系的反应温度、提高锆粉云燃烧的初始温度。ABC粉中NH4H2PO4分解生成NH3,吸收火焰区内大量的热量,在一定程度上会降低火焰区的温度。

Dust cloud test system of minimum ignition temperature and simultaneous thermal analyzer system were used to investigate the minimum ignition temperature of pure zirconium powder,the mixtures of zirconium powder and single flame retardant material in suspended dust cloud state to find out flame retardant materials with better effect,and explored the mechanism.The experimental results indicate that the minimum ignition temperature of 0.2 g zirconium powder was 344℃under the spraying dust pressure of 100 kPa and a constant temperature of 10 s.The minimum ignition temperature of the mixtures of zirconium powder and single flame retardant material in suspended dust cloud state increased with the additive amount of flame retardant materials.Furthermore,the effect of ABC powder was the most obvious,and as its mass ratios were 1∶1,1.5∶1,2∶1,3∶1,the percentage increases of minimum ignition temperature values were 48.35%,81.31%,92.31%,97.8%respectively.The mechanism analysis shows that the reaction temperature of the mixed system decreases and the initial temperature of the combustion of zirconium dust cloud increases because of the evaporation of water in the zirconium powder sample and the decomposition of ABC powder.Meanwhile,the NH3 is decomposed by NH4H2PO4,which absorbs a large amount of heat and decreases the temperature of the flame zone to some extent.