Distribution of CO2 concentration using 2-D modelled HFMC

https://doi.org/10.1016/j.ccst.2022.100028

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The feed gas flows from the top of the contactor, at z=H, where the CO₂ concentration is postulated to be maximum at z/L=H. The solvent flows from the bottom of the contactor, at z=0, where the CO₂ concentration is zero. The axial CO₂ concentration profile along the membrane module is illustrated in Fig. 7a.

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Fig. 7. (a) CO₂ normalized concentration distribution through the HFMC; (b) CO₂ normalized concentration profile along the HFMC (gas flow rate = 6L/hr, solvent flow rate = 1.5L/hr,Tgas=298K,C0=1400ppm,Cs=30wt%).

According to the streamlines, CO₂ from bulk gas is transferred toward the membrane pores due to partial pressure (concentration difference). At the entrance of the module, the concentration decline was sharper, due to higher driving force and contact area, and thereafter decreased gradually.

The dimensionless concentration (C/C_o) for MDEA + KLys, MEA and MDEA solutions are shown in Fig. 7b. In general, lower dimensionless concentration means higher CO₂ removal efficiency. It can be seen in Fig. 7b that the final dimensionless concentration for MDEA + KLys solution is lower compared to MEA and MDEA solutions, as most widely used solvents for CO₂ capture in industry, meaning better CO₂ absorption performance.

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