Mass transfer process of CO2 absorption through non-porous hollow fibre contactor

Abstract

A non-porous hollow fiber contactor containing silicone rubber-polysulphone hollow fiber composite membranes is used for the absorption of CO2. The effects of various absorbents, liquid volumetric velocity, liquid pressure, concentration of NaOH solution and gas pressure on the efficiency of CO2 absorption are investigated. The experiment results indicate that the chemical absorption has a higher absorption efficiency than the physical absorption does and the membrane resistance controls the mass transfer accompanied by chemical absorption. Furthermore, when 2 × 103 mol/m3 NaOH solution is employed as the absorbent, the overall mass transfer coefficient (5.21 × 10-6 mol·m-2 ·s-1·kPa-1) almost reaches the value of permeation without absorption (5.85 × 10-6 mol·m-2·s-1 ·kPa-1), and non-porous hollow fiber contactor has a higher selectivity for the existence of liquid film. Finally, the smooth mass transfer process shows that non-porous hollow fiber composite membrane eliminates bubbling and weeping in the liquid phase, which are frequently encountered in microporous hollow fiber contactor. Therefore, non-porous hollow fiber contactor used in this experiment has a potential for using as a gas-liquid contactor.