Experiment on the promoting-inhibiting effects on methane explosion by using haloalkanes

Abstract

Methane explosion is one of the major disasters that seriously threaten the safety of coal mine production, the development of efficient methane explosion suppression technology can effectively improve the prevention and control level of methane explosion accidents, and its focus is on the function of explosion suppression materials. In order to systematically study the effect of typical haloalkanes extinguishing agents on methane explosion, the effects of typical haloalkanes such as heptafluoropropane (C3HF7), hexafluoropropane (C3H2F6) and trifluoromethane (CHF3) on the ignition and explosion characteristics of methane were systematically studied by combining experimental tests and theoretical analysis. The effects of haloalkanes on methane explosion pressure parameters and laminar burning velocity were tested by a 20 L spherical explosive vessel and a self-developed Bunsen burner laminar flame propagation velocity system. The variation laws of peak explosion pressure, maximum pressure rise rate, laminar burning velocity, and laminar flame morphology evolution were obtained. The results show that with the increase of the added volume fraction, the haloalkanes had a double effect of promoting and inhibiting the methane explosion process. Under the chemical equivalent condition, only C3HF7 can first promote and then inhibit the peak explosion pressure and maximum pressure rise rate of methane, while CHF3 and C3H2F6 can inhibit the effect. The three haloalkanes all showed inhibition on the combustion rate of methane laminar flow. In the oxygen-poor condition, the three haloalkanes inhibited the peak explosion pressure, the maximum pressure boost rate, and the laminar burning velocity of methane. In general, C3H2F6 and C3HF7 have better inhibition effects on methane explosion pressure characteristic parameters and laminar burning velocity than CHF3. The theoretical analysis results show that the double effect of promoting and inhibiting the haloalkanes with the increase of the mixture volume fraction can be attributed to the competition between the improvement of the heat release characteristics of the system reaction and the inhibition of the key free radicals such as H, O, and OH by the main intermediates containing F. The results of this paper provide a theoretical basis for the theoretical research and technical development of methane explosion prevention and control.

Keywords

• methane explosion
• haloalkane
• explosion suppression
• explosion promotion
• explosion pressure
• laminar burning velocity