页岩气中CH4-C2H6吸附-扩散分子动力学研究  

Molecular Dynamics of Adsorption and Diffusion for CH4-C2H6 in Shale Matrix

作　　者：张路[1] 刘朝[1,2] 蔡守银 李期斌 ZHANG Lu;LIU Chao;CAI Shou-Yin;LI Qi-Bin(Key laboratory of low-grade Energy Utilization Technologies and Systems,Ministry of Education,School of Energy and Power Engineering,Chongqing University,Chongqing 400030,China;State Key Laboratory of Power Transmission Equipment and System Security and New Technology,Chongqing 400030,China)

机构地区：[1]重庆大学能源与动力工程学院,低品位能源利用技术及系统教育部重点实验室,重庆400030 [2]输配电装备及系统安全与新技术国家重点实验室,重庆400030

出　　处：《工程热物理学报》2021年第1期40-47,共8页Journal of Engineering Thermophysics

基　　金：国家自然科学基金资助项目(No.51576019)。

摘　　要：本文采用巨正则蒙特卡洛(GCMC)和分子动力学(MD)模拟方法,对比分析了不同温度、压力和孔径对二元气体(CH4-C2H6)在K-伊利石中的吸附-扩散的影响。结果表明,在低压条件下,K-伊利石对C2H6的吸附能力大于CH4,C2H6优先吸附在K-伊利石孔隙表面。热力学因子随着孔径的增加而减小,C2H6的热力学因子大于CH4.气体的自扩散和MS扩散系数、传递扩散系数随着温度的增加而增加。在较高的压力条件下,C2H6传递扩散系数随温度增加而降低。随着压力的增加,CH4和C2H6的自扩散能力均降低,CH4的MS扩散系数和传递扩散系数整体上趋于降低。CH4的自扩散过程更容易发生,但C2H6互扩散能力更强。Combining grand canonical Monte Carlo(GCMC)simulation and Molecular Dynamics(MD)methods,the effects of temperature,pressure and pore size on the adsorption and diffusion property of binary gas in K-illite were compared.It is found that the adsorption capacity of C2H6 is greater than that of CH4 under low pressure,and C2H6 is preferentially adsorbed on the surface of K-illite slit.The thermodynamic factor decreases with the increase of pore size,C2H6 is larger than CH4 according to thermodynamic factor.The self-diffusion coefficient,Maxwell-St efen(MS)-diffusion coefficient and transfer diffusion coefficient of gas increase with the increasing temperature.Under the condition of high pressure,the transfer diffusion coefficient of C2H6 decreases with the increase of temperature.With the increase of pressure,the self-diffusion coefficients of CH4 and C2H6 decrease with the increase of pressure.Moreover,the overall trend of MS-diffusion coefficient and transfer diffusion coefficient of CH4 is decreasing.The self-diffusion process of CH4 appears easily,but the mutual diffusion ability of C2H6 is stronger in binary mixtures.

关 键 词：页岩气 甲烷 乙烷 吸附 扩散 分子动力学 

分 类 号：TE319[石油与天然气工程—油气田开发工程]