Coupling Inhibition Effects of Dry Water Modified by Potassium Carbonate and Hexafluoropropane on Methane Explosion

Explosion suppression technology plays a vital role in reducing the hazardous effect of gas explosion incidents. This study aimed to investigate the explosion suppression effect of two-phase composite inhibitor mixtures of hexafluoropropane and dry water modified by potassium carbonate. The explosion pressure and time parameters of methane-air mixtures were obtained experimentally. Then the synergistic mechanisms on methane explosion suppression was analyzed theoretically. Results of the experiments shows that the combustion time of methane-air mixtures increase with the rising ratio of dry water modified by potassium carbonate in the coupled inhibitors. Dry water modified by potassium carbonate greatly enhanced the explosion suppression effect of C₃H₂F₆. The critical inhibition ratios of gas-solid inhibitors are 5%-6 g, 3%-6 g, and 1%-4 g for fuel-lean, stoichiometric, and fuel-rich methane-air mixtures, respectively. Moreover, the physical inhibition effects of the dilution in the premixed mixtures and the reduction in the flame temperature, as well as the chemical suppression effect, synergistically inhibit the deflagration of methane-air mixtures. In terms of the chemical inhibition, it is KCO₃, KOH, OH and fluorine-containing groups that produced by the pyrolysis of potassium carbonate and C₃H₂F₆ reduce the concentration of key radicals of methane explosion. The results of the work will help to providing the theoretical basis for the development of more effective explosion-suppressant and promoting the related explosion-suppressing technology.