Experimental and Theoretical Analyses of Effects of Membrane Properties on CO₂ Absorption Performance of a Hollow Fiber Membrane Contactor

Abstract

Use of a hollow fiber membrane for chemical absorption of CO₂ is expected to significantly reduce the volume and construction cost of equipment in comparison with a conventional packed tower. In the present study, experiments to examine the effects of membrane properties on CO₂ absorption performance were performed using a counterflow-type hollow fiber membrane contactor. The membrane materials employed were PTFE, PP and PE; and 30 wt% MEA aqueous solution was used as an absorbent of CO₂. In addition, a simulation model was developed to examine the effects theoretically.
Except for the drawn membrane of PE, the measured values of total mass transfer coefficient and CO₂ recovery rate were in good agreement with the values predicted by the simulation, proving the validity of the simulation model developed in this study. The hollow fiber membranes of PP and PE showed high CO₂ recovery rates of 80–90%. On the other hand, the hollow fiber membranes of PTFE were larger in diameter and thickness, resulting in the lowest CO₂ recovery rates. In the case of PTFE, CO₂ recovery rate increased with increasing pore diameter of membrane, which was theoretically supported by the simulation model, while it decreased with increasing pore diameter in most cases of PP and PE.
The drawn membranes of PE showed remarkably high CO₂ recovery rates near 100%, indicating that the drawing treatment of hollow fiber membranes was very effective in enhancing mass transfer through them.