Experimental Study Of Methane Effects On Coal Dust Explosion In20L Spherical Hermetic Device

Coal mine gas explosion accident frequency has plagued safety systems and governments at all levelsin our country, although in recent years, gas explosion accident in mine dropping in the coal industry ofChina, but in the local area and local mining area, the situation still not optimistic. Such as in mine clusters,west owes the developed area, the problem is still serious. In response to the coal mine gas explosion, thestate invested a lot of financial and material resources, established a complete system of safety productionlaws and regulations, organize safety engineer team, and constantly increase investment in securitytechnology research, from the legal, management and technical measures to solve this problem.Based on20L spherical explosive devices developed by laboratory own, from the influence ofconcentration of methane concentration, coal dust and coal dust particle size of three factors on the coaldust explosion properties, studies the characteristics of pure coal dust explosion, methane’s iMPact on coaldust explosion pressure and the lower limit, the following results are obtained.(1)For200g/m~3~800g/m~3of pure coal dust explosion experiment research, the result shows that as thecoal dust concentration increase, the explosion pressure is reduced after rising first, dust particle size below325mesh,325-300mesh,280-240mesh,240-200mesh, all have maximum explosion pressure at600g/m~3.And with the increase of particle size, the maximum explosion pressure of coal dust deduces.(2)For and the concentration below100g/m~3of pure coal dust explosion experiments show that withthe increase of concentration, coal dust explosion pressure value is increasing. And, with the increase ofparticle size of coal dust explosion pressure value is decreasing.(3)For the concentration below100g/m~3of coal dust, methane-coal dust explosion experiment showsthat with the joining methane, on the one hand, improve the coal dust explosion power and on the otherhand reduces the lower explosive limit. For pure coal dust, coal dust under325mesh particle diameter,lower explosive limit is60g/m~3, and after joining methane, corresponding to the lower limit value of1%,3%and5%methane is change to45g/m~3,37g/m~3and30g/m~3. (4)For the powder mixed gas explosion experimental of3%methane and different coal particle size,results show that in close to lower limit concentration range, the particle size has three aspects to explosionpressure and the lower explosive limit: the explosion pressure of a methane mixed coal dust explosion arelarger than the power of pure coal dust explosion, from no methane at the time of the maximum explosionpressure0.2007MPa to0.2501MPa when methane is joined; Second is as the particle size is reduced,explosion intensity increasing, lower explosive limit rising.(5)At the situation of Methane concentration1%~5%, dust concentration below100g/m~3, four kindsof coal dust particle size,and these three factors are all in change, in any case, one of them has regularyinfluence to explosion pressure and the lower limit if the other two keep constant, the influence of this kindof law has the consistent conclusions as conditions of high concentration of dust, orlow volatile pulverizedcoal, and measures the lower explosive limits corresponds to different methane concentration and coal dustparticle size.