煤尘组分对瓦斯/煤尘复合爆炸下限的影响研究

瓦斯和煤尘复合爆炸是煤矿井下爆炸灾害的主要形式之一,研究瓦斯/煤尘复合爆炸下限变化规律,是有效防治煤矿爆炸灾害的必备条件。为研究煤尘组分对瓦斯/煤尘复合爆炸下限的影响,特选用2种组分不同的煤尘(烟煤和无烟煤)。依据EN 14034标准,使用10 kJ化学点火头在标准20L球形爆炸容器中,分别对2种煤尘的最小爆炸浓度、相同试验条件下的瓦斯爆炸下限以及煤尘与瓦斯的复合爆炸下限进行了测量。试验测得烟煤和无烟煤的最小爆炸浓度分别为50 g/m^3和70 g/m^3,瓦斯爆炸下限为4%。当煤尘中分别通入1%、2%、3%、4%的瓦斯后,烟煤最小爆炸浓度分别降低至40、20、5、0 g/m^3,无烟煤最小爆炸浓度分别降低至50、20、5、0 g/m^3。基于上述测量结果,对比分析了煤尘组分对瓦斯/煤尘复合爆炸下限变化规律的影响,并探讨了Le Chatelier、Bartknecht、Jiang等气粉复合爆炸下限预测模型对瓦斯/煤尘复合体系的适用性。结果表明:2种煤尘的最小爆炸浓度均随瓦斯浓度的增大而降低,但挥发分含量低的煤尘降幅更大,即瓦斯对低挥发分煤尘最小爆炸浓度的影响更为显著。Jiang模型预测值远远偏离实际测量值;Le Chatelier模型预测值高于实际测量值,且误差随瓦斯浓度的增大而增大;Bartknecht模型适用性相对较好,且更适用于低挥发分瓦斯/煤尘复合体系。

Influence study of coal dust composition on the lower explosion limit of hybrid mixture of gas and coal dust

The combined explosion of gas and coal dust is one of the main forms of explosion disasters in coal mines. Studying the lower limit change law of the gas/coal dust composite explosion is an indispensable condition for effective prevention of coal mine explosion disasters.In order to study the effect of coal dust composition on the lower explosion limit of hybrid mixture of gas/coal dust,two different components of coal dust (bituminous coal and anthracite coal) were selected. According to EN 14034 standard,the minimum explosion concentration of the two kinds of coal dust,lower explosion limit of methane and the lower explosion limit of methane and coal dust mixtures were measured by using a 10 kJ chemical ignitor in a standard 20 L spherical explosion container. The results show that the minimum explosion concentration of bituminous coal is 50 g/m^3,and that of anthracite is 70 g/m^3 respectively,and the lower explosion limit of methane is 4%. When 1%、2%、3% and 4% was injected into coal dust,the minimum explosion concentration of bituminous coal were reduced to 40 g/m^3,20 g/m^3,5 g/m^3 and 0 g/m^3 respectively,and the minimum explosive concentration of anthracite coal were reduced to 50 g/m^3,20 g/m^3,5 g/m^3 and 0 g/m^3 respectively. According to the measured results listed above,the lower explosion limits of hybrid mixtures of the two kinds of coal dust and gas were measured in a 20 L spherical explosive device.Based on the measured results,the effects of coal dust components on the lower explosion limit of hybrid mixture of gas and coal dust were analyzed. Simultaneously,the applicability of three different models (Le Chatelier,Bartknecht,Jiang) for predicting the lower explosion limit of hybrid mixture to gas/coal dust mixtures was discussed.It is shown that the minimum explosion concentration of the two types of coal dust decreases with the increase of gas concentration,but the coal dust with low volatile content decreases more,that is,the effect of gas on the minimum explosion concentration of low volatile coal dust is more significant. The predicted value of the Jiang model is far from the actual measured value;the predicted value of the Le Chatelier model is higher than the actual measured value,and the error increases with the increase of gas concentration;the Bartknecht model is relatively applicable,and more suitable for low-volatile gas/coal dust composite system.