Experimental Study On Explosion Characteristics Of Methane And Coal Dust

In recent years,the explosion accidents of methane and coal dust frequently occurs. They make heavy loss and serious influences for the enterprises and country. Thus, it is significantly important to study the characteristics for the explosion caused by methane and coal dust.In this paper,lignite coal, gas coal, non-caking coal, lean coal, and anthracite coal are setas research object.Using the test system of minimum ignition temperature of dust cloud, this paper researched the minimum ignition temperature of coal dust cloud. The results indicates that(1)as the coal dust particle sizedecreasing, the ignition decreases;(2)when coal dust particle size is less than 75μm at the same particle size range, the volatile components of coal dust is more, the combustion of coal is easier;(3) the order of experimental for coal sample burned from difficult to easy is anthracite, lean, non-caking, gas and lignite coal.This paper used the 20 L spherical explosion system of gas(dust) to analyze the characteristic of explosion for methane, dust and the mixture of methane and coal dust. The main conclusions are as follows:(1) With the increase of methane concentration, the maximum explosion pressure of methane increases first and then decreases, however, the consuming time to the maximum explosion pressurepresents the opposite trend. Whenthe methane concentration is 9.5%, the maximum explosion pressure of methane is 0.784 MPa,the shortest time to reach the maximum explosion pressureis 127.6 ms.The maximum explosion pressure of methane increases along with the increase of ignition energy and decreases with the decrease of the ignition delay time.And the smaller the concentration, the greater the increase.(2) The best ignition delay time of coal dust is 60 ms when the explosion pressure is biggest.The maximum explosion pressure of coal dust along with the increase of coal dust concentration decrease after first increase. The bestexplosion concentration is 400g/m3 for lignite, 500g/m3 for gas coal, non-caking coal and lean coal, and 600g/m3 for the anthracite respectively. Under the same concentration of coal dust, the maximum explosion pressure of different types coal dust decrease in the orderlignite coal, gas coal, non-caking coal, lean coal, and anthracite coal.(3) Under the same coal dust concentration, the maximum explosion pressure of the mixture in accordance with the methane concentration 7.0%, 9.5%, 12.0%.When the methane concentration remains constant, 400g/m3 lignite coalmakes the maximum explosion pressure of the mixture reach the peak.500g/m3 for gas coal, non-caking coal and lean coal, and 600g/m3 for the anthracite respectively. Under the same coal dust concentration and the same methane concentration, the maximum explosion pressure of the mixture of methane and coal dust is reduced in order of lignite coal, gas coal, non-caking coal, lean coal and anthracite coal.