Metal supported mixed-matrix membranes (MMMs), filled with natural zeolite particles, provide a mean to improve the gas separation performance of inorganic membranes. Microporous natural zeolite powders, clinoptilolite, in alumina silicate matrix were characterized for separation of hydrogen from light hydrocarbons. Both single and multi-component permeation test was used to evaluate the performance of the membrane. At room temperature and a feed pressure of 110 kPa large differences for the separation efficiency of hydrogen from lower n-alkanes were observed for the components under investigation.
The permeation of the weekly adsorbing molecules (e.g. hydrogen) was found to drop at room temperature and resulting in lower selectivities in presence of strongly adsorbing molecules in favor of hydrogen.
Experimental analysis showed that for mixtures of a fast, weakly adsorbing component and a slow, strongly/moderately adsorbing components, the maximum selectivity for hydrogen separation obtained with microporous is about a factor of 2 lower than the one obtained under ideal single gas permeations. Mixed matrix membranes coated on stainless steel supports were found to have as much as two times higher ideal selectivity for H2 over each light hydrocarbon than would be predicted by Knudsen diffusion.