Study Of Suppression Materials' Characteristics And Effects On Gas Explosion

At present, the situation of national coal mine production safety is very severe. Gas explosion accidents occur frequently. With this background, it is very important and urgent to control gas explosion. In order to slove the problem, large amount of suppressing gas explosion experimentals were studied in this thesis. According to the special effect possessed by nanometer material, aerosols and activated saltwater fog which have nano-meter characteristics, natural diatomite with nanoporous structure, nano-SiO₂, etc, were used as suppressants, and comparison of explosion suppression performance of these nano-materials with that of the ultrafine powder of magnesium series , aluminium series, phosphor series was studied, which based on the feasibility analysis of suppressing explosion.Using self-designed and improved XKWB-S and XKWB-1 experimental devices of gas explosion, while considering the kind, particle size and addition quantity of explosion suppression material, the explosion limit, explosion induction period, peak speed of explosion flame, maximum explosion pressure, rate of pressure rise and the time of occurring pressure peak ,ect, were detected as the index to study on the change law of flame spread and pressure variation in the process of gas explosion suppression. The results showed that the influence of different materials on flame spread and pressure characteristic parameter during gas explosion are diffent, different material can inhibit the explosion in different degree and had the best dosage. Especially, non-Cooling aerosols, activated KCl water fog and NH₄H₂PO₄ power were chosen and properly arranged under existing experimental device and conditions, better effect were obtained.The equation of overall reaction rate for fire damp explosion has been established by steady state method. Through numerical calculation and analysis, detailed thermodynamic micromechanism and microcosmic dynamics for chain reaction of gas explosion system, which included 8 element reactions, were carried out by appling Gaussian Software. It was shown that HO₂ free Radical, HCO free Radical and O free Radical, which were produced during the course of reaction, had decisive significance to gas explosion. It was put forward that removing HO₂, HCO and O free Radical is the key factor to limit gas explosion. And it was verified that suppressing explosion material series were very effective for removing these free Radicals. Based on the above analysis, through the active free radical chain reaction theory, the nature of inhibitory effect for gas explosion was discussed and reduced in respects as material nanocrystallization, equivalent principle of free radicals and atomicity with the same number of outer electron, etc.These results from suppressing explosion experiments and analyzing roles for gas explosion suppression provided an important reference and basis for prevention of the mine gas explosion.