Characterization of natural zeolite membranes for molecular hydrogen/carbon dioxide separations by single gas permeation.

摘要

Membrane-based processes have the potential to overcome the limitations of conventional hydrogen separation techniques such as high energy consumption and environmental concerns. Natural zeolite membranes have recently been shown to demonstrate apparent molecular sieving of H2 from H2/CO 2 mixtures and can be used as a model for the development of robust molecular sieve membranes with superior separation characteristics.;The focus of this thesis is the characterization of natural clinoptilolite membranes made from dense mineral deposits by single gas H2 and CO2 permeation. Permeability values as a function of temperature and pressure were analyzed based on mass transport fundamentals of gas permeation through zeolite and non-zeolite pathways. Simple comparative parameters were introduced to characterize natural zeolite membranes. H2 and CO 2 fluxes through the membranes were fitted with a model based on a combination of zeolitic, Knudsen and viscous transports so that the selective and non-selective flux fractions could be quantified.