Moments method applied to the in-situ characterisation of normal butane mass transfer in MFI zeolite membranes

In most of the literature the performances of zeolite membranes are studied under steady state permeation conditions. With this type of experiments, extracting mass transfer parameters is often complex due to the non linearity of the studied phenomena. As a consequence, we propose in the present paper an original membrane transient characterisation method, derived from the concentration pulse chromatography (CPC) technique, applied in the linear response domain. With this method, short concentration pulses are injected at the membrane inlet and the concentration evolution as a function of time is measured at the outlet of the membrane. These data were analysed with the moments method, which allowed the estimation of two groups of mass transfer parameters. This approach has been validated with a first series of preliminary tests which gave promising results.