Experimental exploration and mechanism analysis of the deflagration pressure of methane/pulverized coal blenders inhibited by modified kaoline-containing compound inhibitors

In this work, with the assistance of the intercalation modification approach, three kinds of intercalated compounds, dimethyl sulfoxide (DMSO), potassium acetate (KAc), and ammonium sulfamate (AS) were successively employed for modification on kaoline to prepare a modified kaolin inhibitor. Then, the TG/DTG test, SEM observation, XRD characterization, and FTIR analysis were respectively utilized to probe the thermal stability, surface structures, and functional groups of the modified kaoline inhibitor. Moreover, the compound inhibitors fabricated by modified kaoline powder blending with ammonium polyphosphate (APP) of different mass fractions were employed to inhibit the explosions of methane/pulverized coal blenders. In the explosion inhibition experiments, the concentrations of methane and coal dust were respectively selected for 9.5 % and 0.105 g/L, while the compound inhibitors with seven various mass fractions of 0.05, 0.075, 0.1, 0.125, 0.15, 0.175, and 0.20 g/L were severally chosen to explore its inhibiting effect on methane/pulverized coal blenders using the 20-L standard spherical explosion apparatus. Results show that both the modified kaoline inhibitor and its compound inhibitor demonstrate a prominent inhibiting effect on methane/pulverized coal blenders. Besides, the inhibiting effect presents the most outstanding as the mass fraction for APP of the compound inhibitor occupies 35 %. Under such a circumstance, the P max of the hybrid mixture decreases from 0.784 to 0.47 MPa and declines by 40.05 % after adding the compound inhibitor, the dP / dt max declines to 3.03 MPa·s −1 while the t P max delays to 1.122 s. Finally, we theoretically analyzed the suppression mechanism of the modified kaoline-containing compound inhibitors on the explosions of methane/pulverized coal blenders based upon the physicochemical properties of the raw samples and the solid particles collected from the post-explosion experiments from the macro and molecular-kinetics perspectives. This preliminary study would contribute to the development of high-efficiency inhibitors for preventing methane/pulverized coal-involved explosion disasters.