摘要
生物甲烷路线在CO2减排和节能方面有很大的应用前景。而对生物沼气的分离是此路线的一个关键问题,特别是在60℃和0.1 MPa下。巨正则Monte Carlo(GCMC)和平衡分子动力学(EMD)的分子模拟方法研究CO2和CH4在不同管径的碳纳米管(CNT)中的吸附和扩散,可以从分子层面研究生物沼气的分离机理。分别计算了CO2/CH4二元混合物吸附量、吸附选择性、自扩散系数和渗透选择性等参数。模拟结果表明:由于碳管的受限空间和CO2与碳纳米管壁面分子之间强相互作用,导致二元等物质的量的混合物CO2/CH4的吸附量和扩散系数的差异。CO2的吸附量和自扩散系数都比CH4的大。渗透选择性在碳管管径达到最接近1 nm时达到最大值,此时混合物的分离过程是吸附控制,而非扩散控制。
Biomethane route has large potential in emission reduction and energy saving. One of the key issues is separation of biogas in operating conditions of 333 K and 0.1 MPa. Grand canonical Monte Carlo （GCMC） and equilibrium molecular dynamics simulations （EMD） were used to compute adsorption loadings and self-diffusivities of CH4/CO2 at various diameters of carbon nanotube （CNT） bundles. Single component and equimolar gases were simulated. CO2 always had larger adsorption loading and diffusion coefficient than CH4 as the result of relatively strong interaction between CO2 molecules and tube walls, due to the confined capacity. The permselectivity reached a maximum in closely 1 nm, and under such conditions the separation process was controlled by adsorption rather than diffusion.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2014年第5期1736-1742,共7页
CIESC Journal
基金
国家重点基础研究发展计划项目(2013CB733501)
国家自然科学基金项目(21176113,21136004,21206070,91334202)
江苏高校优势学科建设工程项目~~
关键词
分子模拟
碳纳米管
生物沼气
分离
自扩散
选择性
molecular simulation
carbon nanotube
biogas
separation
self-diffusion
selectivity
