Membrane Contactors for Postcombustion Carbon Dioxide Capture: A Comparative Study of Wetting Resistance on Long Time Scales

The major complication of membrane contactors for gas absorption processes is the gradual wetting of the membrane which increases the mass transfer resistance and annihilates process intensification performances. Two standard membrane materials (microporous PP and PTFE) are compared to two novel composite hollow fiber materials: a dense skin layer on the liquid side prevents wetting (a PMP and a Teflon-AF dense skin coated on a PP fiber). The contactors were tested over 1000 h for CO2 absorption in a 30% MEA solution. The stability of the CO2 capture efficiency over time and the overall mass transfer performances are presented and discussed. A noticeable wetting protection effect of the dense skin membranes is obtained. A large decrease of the capture efficiency is observed with PP, and a slight decrease only is obtained with PTFE. The potentialities of the different fibers for process intensification purposes on long time use is discussed.