(248d) Microfibrous Entrapment of Zeolites for High Duty Cycle Oxygen Enrichment from Air

This paper discusses the results of an experimental study of oxygen enrichment of air using nitrogen-selective sorbents and also the dynamics of the system. The sorbents consist of molecular sieves and other cation exchanged zeolites. The aim of the study is to develop a regenerable enrichment manifold comprising of the microfibrous entrapped nitrogen-selective sorbents. Microfibrous material consists of micron sized sorbent particles (25-250µm dia) entrapped in sinter-locked fiber mesh. These materials are prepared using modified wet lay process. The fibers can be made up of metal, polymer or ceramic. Such a material has inherent advantage of lower intraparticle diffusional resistance which leads to higher contacting efficiency compared to equivalent packed bed structures. Other advantages are lower pressure drop, low heat capacity, low thermal mass, high duty cycle, structural integrity and no channeling. The adsorption experiments are carried out in a fixed bed reactor (2cm dia) at room temperature and 1atm pressure. The experimental results are presented in terms of nitrogen and oxygen breakthrough curves. The effect of activation temperature, face velocity and inlet nitrogen concentration on the activity of sorbents is discussed. The stability of the system is tested for multiple adsorption-regeneration cycles. The initial results indicate that among several zeolites tested, LiX and LiLSX type zeolites are the most efficient. For regeneration studies, no significant capacity loss was observed for up to 5 cycles for both of the materials.