Study on porous structure and gas diffusion characteristics of primarystructure coal and tectonic coal

In order to study the porous structure and the gas diffusion characteristics of the primary structure coal and the tectonic coal, a mercury intrusion, cryogenic liquid nitrogen, carbon dioxide adsorption and pressure stabilized adsorption experiment were applied to the experiment study on the experimental coal samples. The paper had an analysis on the porous structure characteristics of the primary structure coal and the tectonic coal and as well as the time effect of the adsorbed gas under the partical condition. A relationship between the pore complicated degree and the gas migration fast and slow speed in the coal partical of the primary structure coal and tectonic coal was obtained. The study showed that in Qinan Mine and Daning Mine, the micropore length of the primary structure coal was 8.087×1010 m/g and 1.202×1011 m/g individually and the micropore length of the tectonic coal was 6.932×1010 m/g and 1.090×1011 m/g individually. Under the certain condition of the experiment coal samples, the adsorption of the primary structure coal to reach a balanced state would have a required time far longer than the tectonic coal. In the first three minutes, the average adsorption rate of the tectonic coal would be 3.3 and 3.8 times higher than the primary structure coal individually. In the coal samples, the smaller the micropore length, the shorter diffusion path of the gas in the coal would be, the shorter time required of the migration would be and the higher gas adsorption volume in the initial period would be.