(376aj) Molecular Simulation on Separation of CO2/CH4 Mixture By Carbon Membrane with Zigzag Pore Structure
Zigzag-type pore structure was proposed for the separation of CO2/CH4 binary mixture by CMSM. Defect-free pore and three kinds of defect pores, i.e., random, uniform and partial defects, were considered to improve the separation performance. Adsorption and diffusion behaviours of pure gases and gas mixture were simulated by the Grand-Canonical Monte-Carlo (GCMC) method and the Non-Equilibrium Molecular Dynamics (NEMD) method, respectively. Operating pressure ranged from 10 to 100 kPa and temperature was between 273 and 348 K during simulation. The simulative isotherms of CO2 and CH4 showed an acceptable agreement with the experimental data for the defect-free pore of 0.67 nm in size at 298 K. Examination on the effect of pore sizes showed that 0.67 nm was the appropriate option for separation. The total selectivity was 20.1 at 298 K and 100 kPa with the pore of 0.67 nm, which is consistent with the experimental value. The adsorption was determined as the dominant separation mechanism between adsorption and diffusion. Compared with the defect-free pores, the introduction to the random and uniform defect pores can improve the total selectivities and the random defect provided the superior separation performance. Appropriately low temperature and small pore size were beneficial to the separation.
The authors express their sincere appreciation to the financial supports from the Fundamental Research Funds for the Central Universities of China (DUT17JC07) and the National Natural Science Foundations of China (21376037, 21436009).
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