Hollow fibers are the most widely used geometry in current
membrane gas separation applications because they possess many
advantageous features (Chen et al., 2004). Weller and Steiner published
the first mathematical model for membrane gas separation
assuming a well mixed single stage (Weller and Steiner, 1950). Since
then, many models have been proposed to study and analyze the
cross-flow, co-current and counter-current contacting patterns for
a wide variety of membrane gas separation applications. Those
works include that of Coker et al. who reduced the differential equations
describing the performance of multi-component gas separation
modules to a set of algebraic equations by dividing the
module along the axial direction into a series of well-mixed stages
(Coker et al., 1998). Alternatively, Wang et al. directly solved the
set of differential equations that describe module performance
including the effects of pressure drop, concentration polarization
and non-ideal gas behavior for binary gas separations (Wang
et al., 2002).