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利用巨正则蒙特卡罗模拟方法对甲烷在石英中吸附行为进行了研究,并讨论了不同孔径、不同温度、不同含水量和不同组成对甲烷在石英中吸附行为的影响。研究结果表明:甲烷超额吸附量随着压力的增大而先上升后下降,且随着孔径增大逐渐减小;甲烷与石英相互作用能随着压力增大或孔径减小而减小,说明甲烷在孔中吸附逐渐由能量较高的吸附位向能量较低的吸附位转移;随着温度升高,甲烷等量吸附热减小,甲烷在孔中吸附逐渐由能量较低的吸附位向能量较高的吸附位转移,造成甲烷在石英孔中吸附能力降低,导致甲烷吸附量减小;水分子在孔中以定向方式占据着石英孔壁面,且受到范德华力和静电能共同作用在孔中以堆积形式存在;随着含水量增加,甲烷分子在孔中吸附位并没有随着发生变化,即水分子只占据甲烷分子吸附空间,造成甲烷吸附量减小;气体与石英间相互作用能量大小顺序为氮气>甲烷>二氧化碳,则石英上吸附能力大小的顺序为二氧化碳>甲烷>氮气;多组分竞争吸附中,甲烷在气相中摩尔分数降低、甲烷分子吸附位变化以及甲烷吸附空间减小,综合作用导致了甲烷吸附量减小。
Adsorption behavior of methane in quartz was studied by using the method of giant regular Monte Carlo simulation. The effects of different pore sizes, different temperatures, different water contents and different compositions on the adsorption behavior of methane in quartz were discussed. The results show that the excess methane adsorption increases first and then decreases with the increase of pressure, and decreases with the increase of pore diameter. The interaction between methane and quartz decreases with the increase of pressure or the decrease of pore diameter, The adsorption of methane in the pores gradually shifts from the higher energy adsorption sites to the lower energy adsorption sites. As the temperature rises, the isothermal adsorption heat of methane decreases and the adsorption of methane in the pores gradually shifts from the lower energy adsorption sites Methane adsorption in the quartz hole decreases, resulting in reduced methane adsorption; water molecules in the hole to occupy the orientation of the quartz hole wall, and by van der Waals force and electrostatic energy together in the hole With the increase of water content, the adsorption sites of methane molecules in pores do not change with time, that is, the water molecule occupies only the adsorption space of methane molecules, resulting in the decrease of methane adsorption; the interaction energy between gas and quartz In the order of nitrogen> methane> carbon dioxide, the order of adsorption capacity on quartz is carbon dioxide> methane> nitrogen. In multi-component competitive adsorption, the molar fraction of methane decreases in the gas phase, Sub-level change and adsorption of methane adsorption space is reduced, the combined effect results in the methane adsorption amount decreases.