| The 13-1 coal seam in the Liuzhuang Mine is rich in resources.It is the main mining layer and CBM development layer of the mine,as well as the coal and gas outburst coal seam.Due to the simultaneous action of shear force and structural pressure,the permeability of the 13-1 coal seam is relatively poor,gas movement is difficult,gas is easy to accumulate,and the overall strength of the coal seam is weak,which increases the risk of outburst.At present,there are few reports on the adsorption and desorption characteristics of 13-1 coal,which has certain constraints on the comprehensive management of mine gas and the development of coalbed methane.In order to prevent the 13-1 coalbed gas disaster accident and the effective utilization of gas resources,this article uses "Experimental Research on the Adsorption and Desorption Characteristics of 13-1 Coal in Liuzhuang Mine".Combining experimental research and theoretical analysis to study the pore structure characteristics of 13-1 coal,from the perspectives of adsorption statics,thermodynamics and desorption kinetics,the adsorption and desorption characteristics of 13-1 coal under experimental conditions are analyzed,which provides corresponding theoretical and technical support for the development of 13-1 coalbed methane and underground gas control in Liuzhuang Mine.(1)Using scanning electron microscopy and mercury intrusion experiments,it was found that the pore connectivity of 13-1 coal is poor,mostly semi-closed pores and closed pores,poorly developed pore and fissure system,single pore size distribution,and low permeability.(2)Through adsorption experiments under different temperature and pressure conditions,it is concluded that if the temperature is constant,the amount of gas adsorption increases with the increase of pressure,and decreases with the decrease;if the pressure is constant,the amount of gas adsorption increases with the temperature.When it increases,it decreases,and when it decreases,it increases.If the temperature and pressure are increased at the same time,the gas adsorption capacity in the experiment shows a steady increase.In the Langmuir adsorption model,when the temperature continues to increase,the adsorption constant a first decreases,then increases,and finally decreases and continues.When the temperature is 45?,the adsorption constant a reaches its peak,and the adsorption constant b is related to the temperature.Inversely proportional.In the Freundlich adsorption model,1/n<1 and is n directly proportional to temperature;the adsorption constant K is inversely proportional to temperature.(3)From the perspective of adsorption thermodynamics,it is concluded that the pressure increases,the spontaneous degree of gas adsorption increases,and with the increase of temperature,the greater the free energy.The amount of adsorption is positively correlated and negatively correlated with isosteric heat of adsorption and adsorption entropy,and temperature changes have little effect on adsorption entropy.(4)From the perspective of desorption kinetics,it is concluded that the higher the desorption temperature,the more obvious the monotonous increase of the initial gas desorption amount(the first 1 minute),and the gas desorption rate is positively correlated with temperature;10 minutes before the desorption experiment,as the temperature increases,the initial effective diffusion coefficient and diffusion kinetic parameters both increase significantly,and the increase is most obvious at 35?-40?;Using the Arrhenius empirical formula,the gas diffusion activation energy is calculated to be 25.2767kJ/mol.Figure[37]Table[17]Reference[97]... |
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