any real separation application, membranes are exposed not to pure gases but to
gas mixtures. Separation performance is usually estimated by comparing
permeabilities of gases tested individually, but many gases interact with the
membrane and with each other in ways that influence each other’s permeability.
Materials that perform well in pure gas laboratory tests often fail to perform
under real world conditions, but testing under these conditions requires
sophisticated equipment. To meet this need, the AMPMC created ten permeation
boxes that can test gas mixtures in addition to single gases, at pressures up
to 50 bar, using a variation of the standard time lag method. Mixture inlet and
outlet compositions are determined by gas chromatograph using a sampling
technique developed at KAUST.