基于绝对吸附量的页岩吸附CH4和CO2的热力学特征  

Adsorption thermodynamic property for CH4 and CO2 of shales based on absolute adsorption capacity

作　　者：薛培 祁攀文 杨添麒 孙德瑞 张丽霞 高栋臣 XUE Pei;QI Panwen;YANG Tianqi;SUN Derui;ZHANG Lixia;GAO Dongchen(Research Institute,Shaanxi Yanchang Petroleum(Group)Co.Ltd,Xi’an,Shaanxi 710075,China;Shaanxi Engineering Technology Center of Shale Gas Exploration and Development,Xi’an,Shaanxi 710075,China)

机构地区：[1]陕西延长石油(集团)有限责任公司研究院,陕西西安710075 [2]陕西省页岩气勘探开发工程技术研究中心,陕西西安710075

出　　处：《山东科技大学学报（自然科学版）》2019年第5期21-30,共10页Journal of Shandong University of Science and Technology(Natural Science)

基　　金：国家科技重大专项(2017ZX05039-001);延长石油科技计划项目(ycsy2017ky-A-20-3)

摘　　要：为从热力学角度揭示陆相页岩对CH 4和CO 2的吸附机理,选取鄂尔多斯盆地延长组页岩进行不同温度下的CH 4和CO 2等温吸附实验,分析了过剩吸附量与绝对吸附量的差异,进而利用Clausius-Clapeyron方程研究了基于不同类型吸附量的吸附热力学特征。研究结果表明:绝对吸附量大于过剩吸附量,二者差值随温度升高而减小,随压力升高而增大,且吸附气为CO 2时,二者差值较CH 4大;采用过剩吸附量获得的等量吸附热明显偏高,并存在低吸附量阶段的负值现象,应当采用绝对吸附量计算等量吸附热;等量吸附热与吸附量间满足线性正相关,且吸附CH 4的等量吸附热大于CO 2,吸附CH 4和CO 2的绝对初始等量吸附热分别为52.04和27.71 kJ/mol,说明延长组页岩对CH 4的吸附作用力较强。In order to reveal the adsorption mechanism for CH 4 and CO 2 of continental shale from the perspective of thermodynamics,isothermal adsorption experiments under different temperatures were carried out with shales of Yanchang Formation in Ordos Basin.The difference between excess adsorption capacity and absolute adsorption capacity is analyzed.Futhermore,the adsorption thermodynamic characteristics based on the different types of adsorption capacity was investigated by using Clausius-Clapeyron equation.The results show that the absolute adsorption capacity is larger than the excess adsorption capacity.The difference level between them decreases with increase of temperature while increases with increase of pressure.When the adsorbed gas is CO 2,the difference value is greater as comfared to that of CH 4.The isosteric heat of adsorption obtained by excess adsorption capacity is obviously higher,and there is a negative phenomenon in the low adsorption,capacity stage.The absolute adsorption capacity is necesary to calculate the isosteric heat of adsorption,resulting in linear positive correlation with adsorption capacity.For the same adsorption capacity,the isosteric heat of CH 4 adsorption is greater than the isosteric heat of CO 2 adsorption.The absolute initial isosteric heat of CH 4 and CO 2 is 52.04 and 27.71 kJ/mol respectively,suggesting that the shale of Yanchang Formation has strong adsorption for CH 4.

关 键 词：延长组页岩 等温吸附 过剩吸附量 绝对吸附量 等量吸附热 

分 类 号：P618.11[天文地球—矿床学]