Oxygen separation through U‐shaped hollow fiber membrane using pure CO 2 as sweep gas

A number of U‐shaped K 2 NiF 4 ‐type oxide hollow fiber membranes based on (Pr 0.9 La 0.1 ) 2 (Ni 0.74 Cu 0.21 Ga 0.05 )O 4+δ (PLNCG) were successfully prepared by a phase inversion spinning process. The PLNCG hollow fiber membranes were then used to investigate the effect of CO 2 concentration in both the sweep gas and the feed air on the oxygen permeation flux. With pure CO 2 as the sweep gas and even 10% CO 2 in the feed air, a steady oxygen permeation flux of 0.9 mL/min · cm 2 (STP) is obtained at 975°C during 310 h, and no decline of the oxygen permeation flux is observed. XRD, SEM and EDS characterizations show the spent membrane still maintains the intact microstructure and perfect K 2 NiF 4 ‐type phase structure without carbonate, which indicates that the U‐shaped PLNCG hollow fiber membrane is a very stable membrane under CO 2 atmosphere and has great potential for the practical application in oxyfuel techniques for CO 2 capture and storage.©2011 American Institute of Chemical Engineers AIChE J, 2012