密闭空间油页岩粉尘爆炸特性研究

Explosion characteristics of oil shale dust in a confined space

为探究油页岩粉尘的爆炸特性,以龙口(Longkou,LK)、茂名(Maoming,MM)、桦甸(Huadian,HD)和抚顺(Fushun,FS)4种油页岩粉尘为研究对象,采用20 L球形爆炸装置,对这4种油页岩粉尘样品开展系统的爆炸实验,探讨油页岩粉尘的粉尘云质量浓度、粒径、挥发分、灰分、氧含量等对其爆炸特性的影响。结果表明:挥发分含量越高,油页岩粉尘的最大爆炸压力p_(max)、最大压力上升速率(dp/dt)_(max)越高,爆炸下限越低;挥发分和灰分对油页岩粉尘云爆炸分别有显著的促进和抑制作用。在37.52~106.43μm粒径范围内,这4种油页岩粉尘样品的p_(max)和(dp/dt)_(max)均随其粉尘粒径的增大而降低,且到达最大爆炸压力的时间逐步缩短,说明小粒径油页岩粉尘较高的脱挥发速率能提高爆炸的反应程度。当粉尘质量浓度在400~2500 g/m^(3)范围内时,p_(max)和(dp/dt)_(max)均随粉尘云质量浓度的升高呈现先升高后降低的变化趋势,高于最佳粉尘云质量浓度(1000 g/m^(3))时略有下降,但维持在较高水平,表明超过最佳质量浓度的粉尘云引燃后仍有较强的破坏力;LK样品的p_(max)和(dp/dt)_(max)均最高,分别为0.61 MPa和29.32 MPa/s,与挥发分含量相当的褐煤在同一水平,其爆炸下限为200 g/m^(3),在4种样品中最低,高于挥发分含量相当的褐煤;在N_(2)惰化条件下,LK样品的p_(max)和(dp/dt)_(max)均随环境氧含量的降低而降低,当氧含量降至15%时,系统不再发生爆炸,极限氧含量为16%。

To investigate the explosion characteristics of oil shale dust,four kinds of oil shale dust from main mining areas such as Longkou(LK),Maoming(MM),Huadian(HD)and Fushan(FS)in China were chosen as experimental samples.A 20-litre explosion sphere vessel was used as the experimental device to carry out explosion experiments to systematically explore the influences of the parameters of the samples,including dust mass concentration,particle size,the content of volatile and ash,and oxygen content on the explosion characteristics of oil shale dust.The experimental results show that the higher the volatile content of the oil shale,the higher the maximum explosion pressure,the maximum rise rate of explosion pressure(dp/dt)_(max),and the lower the minimum explosion mass concentration;the volatile has a significant promoting effect on the explosion of the oil shale dust,while the ash has a significant inhibiting effect on it.In the dust particle size range from 37.52 microns to 106.43 microns,the magnitudes of p_(max) and(dp/dt)_(max) of the four oil shale samples all decrease with the increase of particle size,and the time to reach p_(max) decreases gradually as the particle size becomes smaller.The smaller the particles are,the faster the volatiles are released,which can improve the reaction degree of the explosion.In the dust mass concentration range from 400 g/m^(3) to 2500 g/m^(3),the magnitudes of p_(max) and(dp/dt)_(max) of the four samples all took on a trend of increasing first and then decreasing with the increase of dust mass concentration.After the critical pressure concentration(1000 g/m^(3))was exceeded,the explosion intensity decreased slightly,but still maintained at a high level,and still had relatively strong destructive power.The magnitudes of p_(max)(0.61 MPa)and(dp/dt)_(max)(29.32 MPa/s)of the LK sample are the highest in the four samples,which are at the same level as that of lignite with similar volatile content.The minimum explosion concentration(200 g/m^(3))of the LK sample is the lowest among the four samples,which is higher than that of the lignite with the similar volatile content.By using N_(2) as the inert gas,the oxidation,the heat released and the magnitudes of p_(max) and(dp/dt)_(max) of the LK sample all decreased with the decrease of oxygen content.When the oxygen content was reduced to 15%,there were no more explosions in the system,and the limiting oxygen concentration was found to be 16%.