Mass transfer mechanism of CO2 absorption through a non-porous hollow fiber contactor

The mass transfer mechanism of CO2 absorption through a non-porous hollow fiber contactor was studied. In the hollow fiber contactor, silicone rubber-polysulphone hollow fiber composite membranes were used. The effects of various absorbents, liquid volumetric velocity, liquid pressure, concentration of NaOH solution used and gas pressure on the efficiency of CO2 absorption were investigated. A mathematical model of KG was set up, and the results obtained from the model are in good agreement with the experimental results. Both the experimental and calculated data indicate that the chemical absorption has higher absorption efficiency than the physical absorption does, and the mass transfer of the chemical absorption is controlled by the membrane resistance. When NaOH solution with concentration of 2 × 103 mol · m-3 was employed as absorbent, the overall mass transfer coefficient almost reaches the value of individual mass transfer coefficient of the membrane. Finally, the smooth absorption process shows that the bubbling and weeping problems, those are frequently encountered in microporous hollow fiber contactor, can be eliminated by using non-porous hollow fiber contactor. Therefore, the non-porous hollow fiber composite membrane used in our study has application potential of using it as a gas-liquid contactor.