Adsorption Dynamics of Air on Zeolite 13X and CMS Beds for Separation and Purification

Author： Jee Jeong-Geun Lee Sang-Jin Moon Heung-Man Lee Chang-Ha

ISSN： 0929-5607

Source： Adsorption, Vol.11, Iss.1, 2005-07, pp. : 415-420

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Abstract

The adsorption dynamics of N₂, O₂, and Ar in kinetic separation bed with CMS and equilibrium separation bed with zeolite 13X were investigated by using dried air as a feed. In the CMS bed initially saturated with He, Ar was the first breakthrough component showing a small roll-up and N₂ followed at a very close interval. Then, the breakthrough of O₂ occurred with a broad roll-up due to its fast diffusion rate and the relatively slow diffusion rate of N₂. In the zeolite 13X bed initially saturated with O₂, the breakthrough of Ar first occurred with roll-up owing to the strong adsorption of N₂, then the breakthrough of N₂ followed after a very short interval. Based upon these results, the cyclic adsorption dynamics of the zeolite 13X VSA for air bulk separation and CMS PSA for oxygen purification were studied. The five-step two-bed O₂ VSA with zeolite 13X produced O₂ of over 90% purity with high recovery. The MTZ variation of N₂ during the adsorption and vacuum steps was described in detail. In the case of the six-step two-bed PSA process for O₂ purification, O₂ of 99.8+% purity could be produced from the binary mixture (O₂/Ar—95:5 vol.%). The dynamic adsorption behaviors were investigated by using a concentration-dependent rate model incorporated with mass, energy, and momentum balances. The model reasonably predicted the adsorption dynamics at the equilibrium and kinetic separation beds.