含草酸钾的超细水雾抑制甲烷爆炸的特性

为研究含草酸钾的超细水雾对抑制甲烷爆炸有效性的影响，采用自制的半封闭管道进行抑爆实验，研究了草酸钾浓度的变化对超细水雾粒径的影响以及对甲烷抑爆性能的影响，分析了不同浓度草酸钾条件下火焰传播速度、爆炸超压、平均升压速率以及爆炸威力指数参数变化。实验结果表明：添加草酸钾对超细水雾的粒径特性影响较小；对于体积分数为9.5%的甲烷，在相同的通雾时间下，当草酸钾浓度为2%时，抑爆性能最显著，火焰传播速度、最大爆炸超压、平均升压速率以及爆炸威力指数较纯甲烷自由爆炸时分别下降了57.1%、66.3%、77.9%、91.5%；较纯水超细水雾分别下降了43.1%、61.3%、75.3%、90.5%；草酸钾的热解温度较低能够增强超细水雾的物理惰化作用并阻断化学链式反应从而有效抑制甲烷爆炸。

Characteristics on methane explosion suppression by ultrafine water mist containing potassium oxalate

To study the effect of ultra-fine water mist containing potassium oxalate on the effectiveness of suppressing methane explosion, a self-made semi-confined chamber was used for explosion suppression experiments to study the effect of changes in potassium oxalate concentration on the particle size of ultra-fine water mist and the performance of methane explosion suppression. The effects of explosion performance were analyzed. The parameters of flame propagation speed, explosion overpressure, average pressure increase rate and explosion power index were analyzed under different concentrations of potassium oxalate. The experimental results show that the addition of potassium oxalate has little effect on the particle size characteristics of ultra-fine water mist. Under the same spraying time, 2% potassium oxalate concentration shows the most significant explosion suppression performance for the 9.5% volume fraction of methane. Compared with the no spraying condition, the flame propagation velocity, maximum explosion overpressure, average pressure rise rate, and explosion power index decreased by 57.1%, 66.3%, 77.9%, and 91.5%, respectively; compared with pure water ultra-fine water mist suppressing the explosion, those parameters decreased by 43.1%, 61.3%, 75.3%, and 90.5%, respectively. The lower pyrolysis temperature of potassium oxalate can enhance the physical inserting of ultra-fine water mist and block the chemical chain reaction to suppress the explosion of methane effectively.