Abstract A fully dynamic model for mixture gas separation is built in Cu-BTC membranes. A multi-scale method that couples the lattice Boltzmann method with grand canonical Monte Carlo (GCMC) is proposed to investigate the mass transfer process of CO2/CH4 mixture gases in Cu-BTC membranes. The convection and diffusion in the interparticle flow field and the intraparticle diffusion and adsorption in the particle interior are simultaneously considered. The membrane morphology is reconstructed by a sphere-based simulated annealing method. The effects of membrane porosity and particle size on the mass transfer and selectivity of CO2/CH4 mixture gases are predicted. Results show that the selectivity of CO2/CH4 is mainly determined by interparticle and intraparticle mass transfer resistances. Meanwhile, the time of saturation adsorption for CO2 and CH4 both decrease with an increase in porosity but decreases for CO2 and increases for CH4 with an increase in particle size. The selectivity of CO2/CH4 in Cu-BTC membranes decreases with an increase in porosity and particle size. Therefore, membranes with small porosity and particle size should be utilized. Compared with the traditional binary GCMC and ISAT methods based on saturation adsorption, the proposed coupled method is closer to the physical essence of the process because it considers dynamic competitive adsorption. The present method can be helpful in the design of efficient metal–organic framework (MOF) membranes.

中文翻译：

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联合 GCMC 和 LBM 模拟方法通过 Cu-BTC 膜可视化 CO 2 /CH 4 气体分离

摘要 在Cu-BTC膜中建立了混合气体分离的全动态模型。提出了一种将格子 Boltzmann 方法与正则蒙特卡罗 (GCMC) 相结合的多尺度方法来研究 Cu-BTC 膜中 CO2/CH4 混合气体的传质过程。同时考虑颗粒间流场中的对流和扩散以及颗粒内部的颗粒内扩散和吸附。通过基于球体的模拟退火方法重建膜形态。预测了膜孔隙率和粒径对 CO2/CH4 混合气体的传质和选择性的影响。结果表明，CO2/CH4 的选择性主要取决于颗粒间和颗粒内的传质阻力。同时，CO2 和 CH4 的饱和吸附时间都随着孔隙度的增加而减少，但 CO2 的饱和吸附时间减少，CH4 的饱和吸附时间随着粒径的增加而增加。Cu-BTC 膜中 CO2/CH4 的选择性随着孔隙率和粒径的增加而降低。因此，应使用孔隙率和粒径较小的膜。与传统的基于饱和吸附的二元GCMC和ISAT方法相比，所提出的耦合方法更接近过程的物理本质，因为它考虑了动态竞争吸附。本方法有助于设计高效的金属有机框架 (MOF) 膜。Cu-BTC 膜中 CO2/CH4 的选择性随着孔隙率和粒径的增加而降低。因此，应使用孔隙率和粒径较小的膜。与传统的基于饱和吸附的二元GCMC和ISAT方法相比，所提出的耦合方法更接近过程的物理本质，因为它考虑了动态竞争吸附。本方法有助于设计高效的金属有机框架 (MOF) 膜。Cu-BTC 膜中 CO2/CH4 的选择性随着孔隙率和粒径的增加而降低。因此，应使用孔隙率和粒径较小的膜。与传统的基于饱和吸附的二元GCMC和ISAT方法相比，所提出的耦合方法更接近过程的物理本质，因为它考虑了动态竞争吸附。本方法有助于设计高效的金属有机框架 (MOF) 膜。