ASYMMETRIC CELLULOSE-ACETATE HOLLOW FIBERS - STUDIES IN GAS PERMEATION

Gas separation behavior of permeators containing asymmetric cellulose acetate hollow fibers with the dense skin on the outside, facing the feed gas, has been investigated experimentally and theoretically using a sweep gas technique. Two systems were studied: CO//2-N//2, and O//2-N//2 (air). If the membrane structure is assumed to be symmetric or homogeneous, the model complies with the present data much better, compared to the assumption that the membrane is asymmetric. These findings enable the operation of asymmetric hollow-fiber permeators with the feed inside the fiber lumen, which gives better separation in high stage cut situations.