炭膜分离CO2/CH4混合气的分子模拟  

Molecular simulation on separation of CO_2/CH_4 gas mixture with carbon membrane

作　　者：赵昊瀚 潘艳秋[1] 何流[1] 俞路[1] 王同华[1] 

机构地区：[1]大连理工大学化工学院,精细化工国家重点实验室,辽宁大连116024

出　　处：《化工学报》2016年第6期2393-2400,共8页CIESC Journal

基　　金：国家自然科学基金面上与重点项目(21176036,21376037,21436009);国家高技术研究发展计划项目(Z2012AA03A611)~~

摘　　要：针对炭膜分离CO_2/CH_4混合气体的过程,分别采用Materials Studio和Lammps软件进行分子模拟,建立与炭膜孔结构相近的Z字形孔模型,通过实验数据验证了模型的可靠性,通过对CO_2/CH_4纯组分及混合气体在膜孔内的吸附和扩散过程的模拟得到分离系数并探讨气体分离机理。综合吸附与扩散过程的模拟结果表明:适当的低温和较小的孔径有利于实现CO_2/CH_4混合气体的分离;随着温度的升高,CO_2/CH_4的分离系数减小,而且膜孔径对分离系数的排序为0.670 nm>1.005 nm>1.340 nm;在温度为298 K、膜孔径为0.670 nm的操作条件下CO_2/CH_4的分离系数为20.1,与实验数据较吻合。研究结果可为优化炭膜制备提供指导,并为探讨分离过程机理提供依据。A simulation study was conducted in separation of CO_2/CH_4 gas mixture using Materials Studio and Lammps softwares, respectively. Zigzag-type pore model was developed to describe the pore structure and verified by CO_2 adsorption isotherm experimentally determined with home-manufactured carbon membranes. Adsorption and diffusion behaviors of pure gas and gas mixture within the pores of carbon membrane were investigated under different conditions in an effort to explore the separation mechanism. Overall separation coefficient of CO_2/CH_4 adsorption and diffusion was examined in the present study. Results showed that appropriately low temperature and small pore size were beneficial to achieve separation of CO_2/CH_4 gas mixture. As the temperature and the pore size were decreased, the separation coefficient increased. The overall separation coefficient of gas mixture was 20.1 at 298 K of the operating temperature and 0.670 nm of the pore size of membrane, which was consistent with the experimental value. This fundamental research would provide a basis for optimizing the preparation of carbon membranes and for studying the separation mechanism of CO_2/CH_4 gas mixture.

关 键 词：分子模拟 炭膜 孔模型 二氧化碳 甲烷 

分 类 号：TQ028.1[化学工程]