Non-selective membranes for separations

Membranes which give high fluxes without selectivities provide a large interfacial area between fluid phases which is independent of the normal constraints of loading and flooding. These membranes offer a largely unexplored route to separation process intensification. Three examples are given in the paper. First, studies of hollow fiber blood oxygenators show that flows which are only a few percent from uniform can reduce overall mass transfer by an order of magnitude. Second, flat sheet membrane evaporators promise the performance of a centrifugal evaporator at a fraction of that unit's cost. Third, distillation in hollow fibers means that the height of the transfer units can be smaller than 0.1 cm, indeed as small as desired.