甲烷在官能团化石墨中吸附行为的影响因素研究

发布时间：2018-07-05 14:08

本文选题：碳氧比 + 石墨　；参考：《中国矿业大学学报》2017年02期

【摘要】：页岩中干酪根结构简化为不同碳氧比石墨结构,利用巨正则蒙特卡罗模拟方法研究甲烷分子在不同碳氧比石墨中吸附行为,讨论了孔径、温度、含水量和二氧化碳对甲烷在不同碳氧比石墨中吸附行为的影响,在此基础上分析碳氧比变化对甲烷吸附行为影响,揭示了甲烷在不同碳氧比石墨中的微观吸附机理以及温度、水分及二氧化碳对甲烷吸附行为的影响及其微观作用机理.研究结果表明:相同碳氧比中,当孔径从1nm增大到20nm时,甲烷在碳氧比为4孔中的平均等量吸附热从19.65kJ/mol减小为7.88kJ/mol,且甲烷过剩吸附量随微孔孔径增大而增大,而随中孔孔径增大而减小;相同孔径中,当碳氧比从4增加到20时,甲烷在孔径1nm中的平均等量吸附热从19.65kJ/mol减小为16.39kJ/mol,且甲烷过剩吸附量随着碳氧比增大而减小;当温度从313K升高到373K时,甲烷在碳氧比为4孔中的吸附逐渐由能量较低的吸附位向能量较高的吸附位转移,甲烷等量吸附热从12.76kJ/mol减小为12.16kJ/mol,造成甲烷过剩吸附量降低;水分子在孔中受到范德华力和静电能共同作用使其聚集在含氧官能团附近,且水分子占据了甲烷分子吸附空间,造成甲烷过剩吸附量降低;在多元组分竞争吸附中,不同碳氧比石墨对二氧化碳的吸附能力大于甲烷.甲烷在气相中摩尔分数降低、甲烷吸附位的变化以及甲烷吸附空间减小将导致了甲烷吸附能力降低.
[Abstract]:The structure of kerogen in shale is simplified to graphite with different carbon to oxygen ratio. The adsorption behavior of methane molecules in graphite with different carbon / oxygen ratios is studied by means of the great canonical Monte Carlo simulation method. The pore size and temperature are discussed. The effects of water content and carbon dioxide on the adsorption behavior of methane in graphite with different carbon to oxygen ratios were analyzed. The effect of carbon to oxygen ratio on the adsorption behavior of methane was analyzed, and the microcosmic adsorption mechanism and temperature of methane in graphite with different carbon and oxygen ratios were revealed. The effect of moisture and carbon dioxide on methane adsorption and its microscopic mechanism. The results show that when the pore size increases from 1nm to 20nm, the average adsorption heat of methane decreases from 19.65kJ / mol to 7.88kJ / mol, and the excess adsorption capacity of methane increases with the increase of pore size. In the same pore size, when the ratio of carbon to oxygen increases from 4 to 20:00, the average adsorption heat of methane in pore 1nm decreases from 19.65kJ / mol to 16.39kJ / mol, and the excess adsorption capacity of methane decreases with the increase of carbon-oxygen ratio. When the temperature increased from 313K to 373K, the adsorption of methane gradually shifted from the lower adsorption site to the higher energy adsorption site, and the equivalent adsorption heat of methane decreased from 12.76kJ / mol to 12.16kJ / mol, which resulted in the reduction of excess methane adsorption capacity. Water molecules are subjected to the interaction of van der Waals force and electrostatic energy in the pore to make them gather near the oxygen-containing functional groups, and the water molecules occupy the adsorption space of methane molecules, resulting in the reduction of excess adsorption capacity of methane. The carbon dioxide adsorption capacity of graphite with different C / O ratios is greater than that of methane. The decrease of molar fraction of methane in gas phase, the change of methane adsorption site and the decrease of methane adsorption space will lead to the decrease of methane adsorption capacity.
【作者单位】：西南石油大学油气藏地质及开发工程国家重点实验室;
【基金】：国家自然科学基金项目(41602155)
【分类号】：P618.13

【相似文献】