Vacuum sorption pumping studies of argon and oxygen on 4A molecular sieves

Journal Article · Fri Jan 01 04:00:00 EST 1993 · Separation Science and Technology

DOI:https://doi.org/10.1080/01496399308019509· OSTI ID:145151

Perona, J J; Byers, C H ^[1]; Prazniak, J K ^[2]

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1. Oak Ridge National Lab., TN (United States)
2. Oak Ridge Y-12 Plant, TN (United States)

Cryosorption pumping is a method of evacuating enclosed volumes by adsorbing gas on a deep bed of sorbent, such as Davison 4A zeolite, at cryogenic temperatures. Modeling the dynamic behavior of these systems for air pumping requires information on two major constituents of air: oxygen and argon. Particle size variation was the major variable in determining the mechanism of the process. The model comprises a fluid-phase mass balance representing the dynamics of gas in the bed and a spherical, one-dimensional diffusion equation describing adsorption in pellets of 4A zeolite. The present model calculates effective pore diffusivity taking into account Knudsen diffusion, ordinary diffusion, and Poiseuille flow. The primary diffusional resistance appears to occur in the macropores formed by the pelletizing clay binder, rather than in the bed interstices or microporous zeolite crystals.

• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 145151
• Report Number(s): CONF-911049--
• Journal Information: Separation Science and Technology, Journal Name: Separation Science and Technology Journal Issue: 1-3 Vol. 28; ISSN 0149-6395; ISSN SSTEDS
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ADSORPTION
AIR
ARGON
CRYOPUMPS
MOLECULAR SIEVES
OXYGEN
PACKED BEDS
POROSITY
SORPTIVE PROPERTIES
ZEOLITES