Effect of hollow fiber morphology and compatibility on propane/propylene separation

With a large specific area, micro-porous membranes in the geometry of hollow fibers become attractive materials for providing an effective contact area between two phases (e.g. liquid–gas and liquid–liquid). In this study, we used hollow fibers as structured packing materials in the propane/propylene distillation. We investigate the effects of morphology and compatibility of hollow fibers on separation efficiency and operation stability in the distillation process. While a hydrophobic micro-porous membrane may seem preferable for this application, an asymmetric membrane with sub-micron pore size on the liquid side may be more suitable for long-term stability of the distillation operation. A stable operation zone without flooding and loading problems is obtained when the pressure drop across the membrane is in a certain range. Typically, the high separation efficiency (HTU < 30 cm) is obtained when the tested modules are operated inside this stable zone.