| The influence of water on methane adsorption can reveal the prediction and prevention effect of coal seam gas disaster from microscopic point of view.In this paper,from the microscopic point of view,the molecular model of gas-fertilized-coal was constructed by molecular simulation method,and the molecular model and adsorbent were optimized.The saturated configuration and energy distribution of methane and water adsorption by gas-fertilized-coal structure were analyzed,and the influence of water on methane adsorption at different temperatures was analyzed.The effects of water and methane implantation sequence on methane adsorption characteristics of gas-fertilized coal under different adsorption pressures were studied.3,6 and 10 water molecules were added to the molecular model system of gas-fertilized coal saturated with methane adsorption,and the effects of different water molecules on methane adsorption capacity and adsorption heat were studied.The change of methane adsorption capacity and adsorption heat under dry condition and the change of methane adsorption capacity and adsorption heat after adding water molecules were compared to study the influence of water on methane adsorption by gas fertilizer coal.Based on the establishment of water-bearing coal adsorption system with water content of 1.12%,2.26% and 3.72%,methane molecules were adsorbed,and the influence law of gasfertilizer coal with different water content on methane adsorption capacity and adsorption heat was studied.The research conclusions were as follows:(1)At different temperatures,methane adsorption decreases gradually with the increase of added moisture.Under the same added moisture condition,the higher the temperature,the lower the methane adsorption.(2)Under the same adsorption equilibrium pressure,when water is added to methane adsorption equilibrium gas fertilizer coal,the methane adsorption heat and adsorption capacity of water injection coal are obviously lower than that of dry coal;Under the same applied moisture,the saturated methane adsorption capacity of coal increases sharply at first and then slowly to a stable value with the increase of adsorption equilibrium pressure.With the increase of moisture content,methane adsorption decreases gradually.(3)When methane is adsorbed by coal samples with different moisture content,the saturated adsorption amount of methane decreases with the increase of moisture content,and the presence of moisture in coal inhibits the adsorption of methane.With the same water content,the limit adsorption capacity of methane by gas fertilizer coal increases rapidly with the increase of adsorption equilibrium pressure,and then slows down and gradually tends to be stable.(4)the moisture content in the coal facies at the same time,water adsorption methane from coal is less than the water under the condition of adsorption methane from coal samples,this is because the coal adsorption capacity of water is greater than that of coal to methane adsorption capacity,water moisture in coal dominated the early air fertilizer in the structure of coal methane adsorption,cause into methane molecules cannot after adsorption,and methane adsorption saturation before they are put into water,Although the coal has saturated methane adsorption,the water added later will replace part of the methane adsorption site,reducing the amount of methane adsorption in the coal. |
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