草酸盐粉体抑制甲烷爆炸的试验研究

Experimental investigation into the inhibitive effect of the methane explosion via the oxalate powders

为了研究草酸盐粉体抑制甲烷爆炸特性,选取草酸钾、草酸钠、草酸亚铁3种较为常见的草酸盐粉体作为抑爆材料,分析了草酸盐粉体作用下的甲烷爆炸特性。结果表明,3种草酸盐粉体均具有一定的甲烷爆炸抑制作用,其抑爆作用由强到弱依次为草酸钾、草酸钠、草酸亚铁。草酸钾、草酸钠和草酸亚铁的最佳抑爆粉体质量浓度分别为0.22g/L、0.26 g/L和0.26 g/L,最大爆炸压力的降幅分别为33.25%、30.03%和20.83%。结合热重分析和甲烷爆炸抑制特性,探讨了草酸盐粉体的甲烷抑爆作用机理。

The given paper has chosen 3 common oxalate powders( i.e.potassium oxalate,sodium oxalate and ferrous oxalate) for the explosion suppressing substances to trace and identify their inhibiting effect on the methane explosion.The pyrolysis features of the oxalate powders have been analyzed through the thermal gravity analysis( TGA for short) method.As a result of testing and experiments,we have found that,the heating rate turns out for 10 K/min under one unit of the air atmosphere,under the temperature range from 25 ℃ to 800 ℃ by using the 20 L spherical explosion vessel to test the suppression properties of the oxalate powders on 9.5% methane.For the test,we have chosen the mass concentrations of the oxalate powders as 0.10 g/L,0.14 g/L,0.18 g/L,0.22 g/L,0.26 g/L and 0.30 g/L,respectively.And,the analysis of the thermal gravity analysis tests demonstrates that the decomposition temperature of the potassium oxalate tends to be lower than that of the other oxalate powders,hence suggesting that the temperature can be reduced promptly and the heat conduction is easy to be made stopped.The inhibiting test results also reveal that all the 3 oxalate powders are endowed with a certain inhibitive effect on the methane explosion,whose explosion suppression effect can be illustrated in ascending order,say: potassium oxalate > sodium oxalate > ferrous oxalate.What is more,the mass concentration of the said inhibitors may enjoy a great influence on the inhibitive effect of the methane explosion.The optimalized mass concentration rates of the potassium oxalate,the sodium oxalate and the ferrous oxalate can be listed as 0.22 g/L,0.26 g/L and 0.26 g/L respectively,which are in correspondence with the decrease of the maximum explosion pressure of 33.3%,30% and 20.9%,respectively,and a more significant reduction in the maximum pressure rising rate of 92.3%,90.4% and 68.09%,correspondingly.And,simultaneously,the pressure peak time can be made increased in turn by 335%,285% and 79%.Therefore,joining the study of the thermal gravity analysis and the methane explosion suppression features,the methane explosion suppression mechanism of the oxalate powders can be classified into physical effects and chemical effects.In terms of the physical effects,the oxalate powders can absorb the heat by the thermal decomposition,while the gaseous products can shield or prevent the heat conduction and thermal radiation.Thus,in terms of chemical effects,the oxalate powders can be activative in generating some products to reduce the concentration of radicals in the decomposition process in reaction with the radicals of methane explosion.Therefore,physical effects and chemical effects of the sodium oxalate can be made better than the other oxalate powders.