Research On Methane-Coal Dust Compound Explosion Intensity In Enclosed Vessels

The harm of methane-coal dust compound explosion is mainly incarnated on thebreakage caused by explosion over-pressure in industry, so the further and systematicresearch about the main influencing factors to explosion intensity, will provide evidence tomake more logical defend or restrict explosion measures.Prevenient researches on this area were usually aiming at the experimental results insome special conditions, and few quantitative conclusion was attained.The main purpose ofthis paper is to find the most dangerous condition in methane-coal dust compound explosionby investigating systematic experiments, and finally get the quantitative relationship betweenexplosion intensity and methane-coal dust concentration scale, particle diameter,ignitiondelay.Then, the thermodynamics and chemical response dynamics model is built andtheoretical arithmetic of compound explosion is discussed. Idiographic works are included asfollows:(1)The experimental device for dust explosion in confined area, including pressuretransducer,data acquisition card,computer and electric spark ignition device, is used to buildcompound explosion system, the system dynamic response time is less than a millisecond, testprecision is level 0.5;(2)It is confirmed by a large number of methane-coal dust compound explosionexperiments, the most dangerous explosion condition is that methane concentration is 5%,coal dust concentration is 500g/m³,particle diameter is 26μm,ignition delay is 40ms;(3)The experimental results indicate that, explosion intensity (maximum explosionpressure P_max, maximum rate of pressure rising (dP/dt)_max, explosion lasting time t) isquadratic function with methane concentration,coal dust concentration and ignition delay; Asparticle diameter rising,the P_max and (dP/dt)_max first increase and then descend, while the tpresents a tendency of durative increase;(4)The quantitative relate equation within explosion intensity (P_max, (dP/dt)_max, t) andexplosion parameters, is attained by taking regression analysis of the explosion experimentsdata.Thereby,the intensity of methane-coal dust compound explosion in other differentconditions can be estimated; (5)On the basis of experiment results analysis,a computational model for methane-coaldust compound explosion in confined area is founded, and the calculating method is broughtforward. Comparing with experiment results,it can be concluded that the real explosionprocess is well be reflected by the computational model.The new ideas presented in this paper are as follows:(1)The main factors influencing methane-coal dust compound explosion intensity arestudied with systematic experiments, the quantitative relate equation between explosionintensity and characteristic parameter is attained through experiment data regressing.(2) The compound explosion model of methane-coal dust is built here, then theinfluence of methane concentration, coal dust concentration and particle size to explosionintensity is calculated. Comparing the calculating results with experimental data, themaximum windage is 21.33%.