Experimental Research On Suppressing Multiple Combustible Gas Explosions By Ultrafine Powder In Coal Mine

Gas explosion is the serious threat of mine staff and production. It is very necessary to control accidents with effective technologies. So it is greatly important to research the new explosion suppressant for gas explosion disaster prevention and mitigation.Based on the mechanism of gas explosion and powder suppressing explosion, performance analysis and characteristic analysis of ultrafine particles as explosion suppressant were completed, and a series of experiments of multiple combustible gas explosion characteristics and ultrafine powder suppressing explosion were carried out using the type XKWB-1 20L approximate spherical closed device (steel container). Firstly, testing the explosion limit scope and the explosion basic parameters of CH₄-air and CH₄-CO-C₂H₆-H₂-air explosive gas, the feasibility of the experiment system is validation; we can conclude that the explosion floor-limit of Multiple Combustible Gas is below the CH₄-air. And contrast analysis the the explosion basic parameters of CH₄-air and mixed air, conclusion the risk of Multiple Combustible Gas Explosions is higher than the CH₄-air. Secondly, four kinds of powder suppressant, zinc borate,Microns silica,Nano silica,Nano calcium carbonate, were selected. As the CH₄-CO-C₂H₆-H₂-air explosive gas, the effect of four kind of ultrafine powder was tested, based on the parameters that explosion pressure,explosion pressure rising rate and maximum explosive pressure arrival time, and researched the law of the effect of suppressant powder nature and discharge process factors upon explosion suppression effect.Experimental results show that the four kind of ultrafine powder are effective for explosion prevention and initial explosion suppression, the explosion suppression effect of Nano calcium carbonate is the best, next is Nano silica, zinc borate is also better, and the last is Microns silica. After insufflating ultrafine powder, the explosion pressure reduces, but the effect is clear when the powder density proper in reaction container and only during the fixed period of time.The conclusion of this experiment system provide guidance for the development of suppressing multiple combustible gas explosions by ultrafine powder, and lay a foundation for the technology t of the ultrafine powder suppressant.