Preparation of alumina hollow fibers and their use as phase contactors for the removal of dissolved gases

Alumina hollow fibers were prepd. by a combined phase inversion and sintering method. A polymer/solvent [poly(ether-sulfone)/1-methyl-2-pyrrolidinone] system filled with alumina powder is extruded into a nonsolvent bath to form the fibers which are then dried and sintered at high temp. to give alumina fibers. The fibers were characterized using a combined dry and wet gas permeation method and using SEM. Fibers were coated using simple dip coating techniques to study the effects on minimizing defects and max. pore size. More complex techniques have not been used, as there is no need to reduce median pore size given the intended application. Finally fibers were constructed into a module for parallel flow phase contacting. Mass transfer studies were carried out on removal of dissolved O from H2O, Ar was used as a stripping gas. Varied liq. flow, tube side pressure and gas flow were studied. The results were compared with predictions based on known mass transfer correlations for hollow fiber contactors. Mass transfer was strongly limited by diffusion through the liq. filled membrane. By increasing tube side pressure the liq./gas interface could be driven back across the fiber wall resulting in effectively 2 mass transfer layers, one liq. filled layer, and one gas filled layer. Mass transfer is far faster in the gas filled layer so overall mass transfer is improved as the liq. filled layer is reduced. [on SciFinder (R)]