Gas absorption studies in microporous hollow fiber membrane modules

A comprehensive experimental investigation of gas-liquid absorption in a shell-and-tube type microporous hydrophobic hollow fiber device in a parallel flow configuration was carried out. Two modes of countercurrent gas-liquid contacting were studied, the wetted mode (absorbent liquid filled pores) and the nonwetted mode (gas-filled pores). The absorbent flowed through the fiber bore in most of the experiments. The systems studied include pure CO[sub 2], pure SO[sub 2], CO[sub 2] - N[sub 2] mixtures and SO[sub 2] - air mixtures. The absorbent was pure water. The absorption process was simulated for each case with a numerical model for species transport with and without chemical reaction. Laminar parabolic velocity profile was used for the tube-side flow, and Happel's free surface model was used to characterize the shell-side flow. The model simulations agreed well with the experimental observations in most cases. SO[sub 2] removals as high as 99% were obtained in small compact contactors. High K[sub L]a and low height of transfer unit (HTU) values were obtained with hollow fiber contactors when compared to those of conventional contactors. The applications of direct interest here are those for acid gas cleanup.