| Tectonic coal is widely distributed,with large reserves and frequent exploitation.Investigating the adsorption and thermodynamic properties of tectonic coal is important to prevent and control coal and gas outburst.To study the influence of tectonic coal with different mass ratio on gas adsorption and thermodynamic characteristics in the adsorption process of mixed coal samples,the virgin coal and tectonic coal from Tianchi Coal Mine in Shanxi Province were selected.Theoretical analysis and experimental study were carried out.(1)According to laboratory measurements,the robustness coefficient of virgin coal is 1.51,and that of tectonic coal is 0.44.The characteristics of micropores of coal with different degrees of damage were investigated,and it was found that pores and corner pores mainly existed in virgin coal and tectonic coal respectively,while friction pores were mostly developed in mixed coal.The average pore diameter of tectonic coal is the smallest,and the tectonic coal with the largest specific surface area is 1.08 times that of the mixed coal,and the specific surface area is 1.445?1.560 m2·g-1.The pore volume of the mixed coal sample is the smallest,which is only 83.3% of that of tectonic coal,and the pore volume ranges from 0.254 to 0.305cm3·g-1.(2)W Y-98 A was used to carry out isothermal adsorption test.Through the test,it was found that with the increase of tectonic coal mass ratio,the adsorption capacity and adsorption constant a of coal samples showed a parabolic trend of first increase and then decrease,and reached the maximum value when the tectonic coal mass ratio reached 50%.With the increase of the proportion of tectonic coal mass,the adsorption constant b value is opposite to the adsorption constant a value.(3)Through the experimental study on the influence of different influencing factors(temperature,particle size,water content)on gas adsorption capacity,it is found that the adsorption capacity of mixed coal samples at 30? is 1.06 and 1.13 times of that at 40? and 50?,respectively.When the particle size of test coal sample is between 20 mesh and 100 mesh(i.e.,0.83mm?0.15mm),the adsorption amount increases with the decrease of particle size,and there is a certain difference in the gas adsorption amount under different water content conditions.Adsorption constant a showed a linear downward trend with the increase of temperature,and showed a parabolic change with the change of water content and particle size.Through the analysis,it is found that the particle size is the most sensitive factor to the gas adsorption capacity law of the mixed coal sample coMPared with the same period,followed by water content.And temperature has the lowest sensitivity.(4)Based on PCT-C80 test system,gas adsorption heat data of coal samples were obtained.With the increase of ratio of tectonic coal quality,?Had and ?S of the mixed coal sample show a trend of decrease after the first increase,and the adsorption enthalpy Qst and Gibbs free energy shows an opposite parabolic trend.Therefore,when the mass of virgin coal and tectonic coal is equal,the disturbance of coal will lead to a large amount of gas gushes out.The experimental results showed that when the quality of the virgin coal and tectonic coal in the mixed coal sample is equal,the outburst of coal and gas is easy to occur,and corresponding measures should be taken to prevent the outburst accident,so as to ensure the safety of coal mine production and improve the production efficiency of coal mine,which is of important reference significance to the field practice. |
PDF Full Text Request