Characteristics of Acid Leaching and Vibration Coupling Desorption of Gas-Saturated Coking Coal.

ABSTRACT

Permeability is a key factor affecting efficient gas drainage from coal seams, and acidification and vibration shock are effective means to increase permeability in original low-permeability coal seams. To study the gas desorption characteristics of coking coal under the coupling effect of mining disturbance and acidification permeability enhancement, taking the coal seam of Shoushan No. 1 coal as the research object, a self-built adsorption-desorption vibration test platform was used. Acid leaching vibration coupling desorption experiments at vibration frequencies of 0, 30, 60, and 100 Hz were conducted on selected particle coals with particle sizes of 0.18-0.25 and 1-3 mm. The experimental results show that the gas desorption amount of particle coal with the same particle size first increases and then decreases with the increase of vibration frequency, among which the desorption effect is the best under 60 Hz vibration condition. Under the condition of fixed vibration frequency, the desorption amount, initial desorption velocity, and velocity attenuation coefficient of particle coal increase as the particle size decreases. Under the same particle size and vibration frequency conditions, the acid leaching and vibration of coal samples have a synergistic effect on gas desorption, which is manifested in the promotion of gas desorption on the outer surface of the coal sample and the surface of open macropores. The research can provide theoretical reference for coal seam acidification and permeability enhancement under the influence of mining disturbance.