Meikuang Anquan (May 2024)
Experimental study on the influence of multiple factors on gas desorption of coal sprayed with surfactant
Abstract
Under mining conditions, the change of original stress in coal mining face aggravates the desorption of original adsorbed gas and the diffusion and seepage of free gas to varying degrees, which leads to accidents affecting coal mine safety production such as gas overrun. In order to effectively reduce the gas concentration in working face or local area of coal mine, the method of spraying surfactant to specific high concentration gas area is used to inhibit gas desorption. In order to simulate the working condition of inhibiting gas desorption by spraying surfactant solution in coal mine, the effects of mass fraction of surfactant solution and coal particle size on gas desorption under ventilation conditions were studied, and the inhibitory effect of spraying surfactant on gas desorption of coal with different particle sizes under actual coal dust environment was revealed. According to the general situation of working face where gas overrun may exist in underground coal mine, an experimental platform for inhibiting gas desorption by spraying surfactant coal was independently developed. The solution with good wettability was selected by surface tension and settlement experiments. The effects of different mass fractions of surfactant solution and coal particle size on gas desorption were studied. The results showed that when the mass fraction of surfactant solution reached 0.40%, the critical surface tension of octadecyl glucoside APG solution in the five solutions was 26.96 mN/m, and the settling time of coal powder was 18.19 s, indicating that its wettability was the best. When the spray mass fraction is 0. 01% APG - 0. 50% APG solution, the APG solution with different mass fractions has a first-order exponential relationship with the peak gas concentration. When the solution mass fraction reaches a certain degree, the area percentage of oxygen-containing groups tends to be stable with the increase of solution mass fraction. When the spray mass fraction is 0.40% APG solution and the coal particle size is between 2.80 mm and 30.00 mm, the particle size is negatively correlated with the peak gas concentration at the measuring point, but the attenuation rate decreases rapidly, slowly and rapidly with the increase of particle size.
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