氧气体积分数对筒仓混煤爆炸特性的影响研究

Study on effect of oxygen volume fraction on explosion characteristics of silo mixed coal

为了研究氧气体积分数对筒仓储煤爆炸特性的影响,利用20 L球形爆炸装置,在氧气体积分数为21%、15%、10%条件下,对2种热值的筒仓混煤爆炸参数(最大压力p_(max)、最大升压速率*(dp/dt)_(max)、爆炸指数Kst)开展了实验研究,分析了氧气体积分数、热值对筒仓混煤爆炸特性的影响规律。结果表明:混煤爆炸参数随煤尘浓度的增加呈先增大、后减小的变化规律;当氧气体积分数由21%降至10%时,混煤爆炸参数大幅降低,2种热值混煤p_(max)值较空气中分别下降了38.9%和44.8%,(dp/dt)_(max)值分别下降了68.5%和81.1%,爆炸危险性分别由强、中度降至了弱爆炸等级;随着氧气体积分数的降低,混煤p_(max)和(dp/dt)_(max)峰值对应煤尘浓度存在显著差异,即氧气体积分数越小,p_(max)和(dp/dt)_(max)峰值对应煤尘浓度越小;混煤热值对其爆炸特性具有显著影响,在空气条件下,热值越高、爆炸危险性越大,但在贫氧条件下,随着煤尘浓度增加,高热值混煤较低热值混煤具有更低的爆炸危险性。

To study the effect of oxygen volume fraction on the explosion characteristics of silo coal,an experiment was conducted on the explosion parameters (maximum pressure p_(max),maximum pressure rise rate (dp/dt)_(max),and explosion index Kst) of mixed coal in silos with two calorific values and oxygen volume fractions of 21%,15%,and 10%using a 20 L spherical explosion device.The effect of oxygen volume fraction and calorific value on explosion characteristics was analyzed.The results indicate that:first,when the concentration of coal dust increases,the explosive characteristics of mixed coal with three distinct oxygen concentrations increase first and eventually fall;when the oxygen volume fraction decreases from 21%to 10%,the explosion parameters of mixed coal decrease significantly,and the p_(max)peaks of mixed coal with two calorific values decrease by 38.9%and44.8%,respectively,compared with that in air,and (dp/dt)_(max)dropped by 68.5%and 81.1%,respectively;the explosion risk decreased from high and moderate to weak;second,as the oxygen content decreases,the coal dust concentration of the p_(max)and(dp/dt)_(max)peaks of mixed coal changes.The lower the oxygen concentration,the lower the concentration of p_(max)and (dp/dt)_(max)peaks of coal dust.Finally,the calorific value has a substantial impact on the explosion properties of mixed coal.The higher the calorific value,the larger the explosion risk,and under conditions of low oxygen and higher coal dust concentration,the coal with a high calorific value has a smaller explosion risk than coal with a low calorific value.