Spiral wound, hollow fiber membrane modules: A new approach to higher mass transfer efficiency

Abstract A new type of transverse flow, hollow fiber module was evaluated for membrane separation. First, small sections of fabric were woven using silicone rubber hollow fiber membranes and monofilament nylon. Water deoxygenation experiments were conducted on each fabric in a flat cell, yielding mass transfer coefficient ( k ) values. An optimal fabric construction was identified based on k values exceeding 0.01 cm/s at moderate velocities, low pressure drop, and high membrane packing density. Spiral wound prototype modules were made and tested, each with a fabric wrapped in layers around a central permeate tube. For O 2 removal from water, k values for the prototypes were slightly below those obserbved in the flat cell tests. Wrapping the fabric tightly around the permeate tube was less effective than looser wrappings. Pervaporation experiments with trichloroethylene were attempted, but the performance was reduced, apparently due to leaching of petroleum jelly used in module construction and redeposition on the membrane. The k values observed for oxygen transfer were at least 20% higher than those achieved with traditional spiral wound modules, and the membrane packing densities achieved in the prototypes were 300 to 400% higher. This module design could prove to be practical and advantageous for membrane separation processes in which the mass transfer coefficient on the feed side of the membrane limits flux.