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Air separation by integrally asymmetric hollow‐fiber membranes
Author(s) -
Feng Xianshe,
Ivory John,
Rajan Varagur S. V.
Publication year - 1999
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690451013
Subject(s) - countercurrent exchange , concentration polarization , integrally closed , membrane , permeation , materials science , polarization (electrochemistry) , membrane technology , gas separation , hollow fiber membrane , nitrogen , chemistry , chemical engineering , chromatography , analytical chemistry (journal) , composite material , engineering , thermodynamics , physics , biochemistry , organic chemistry
Integrally asymmetric hollow‐fiber membranes each with an outer skin layer and a porous substrate were studied for air separation to produce nitrogen and oxygen enriched air. The test on both bore‐side feed and shell‐side feed with cocurrent and countercurrent flow arrangements for a wide range of stage cuts shows that the bore‐side feed countercurrent flow was the most advantageous configuration in the permeator design. When operated in the bore‐side feed countercurrent configuration, the permeator performance compared favorably with the commercial systems available for nitrogen production. A mathematical model was developed for this configuration. Since the concentration polarization in the substrate was a major concern for the bore‐side feed configuration, especially for high stage‐cut operations, a theoretical approach was pursued to formulate the concentration polarization. This allows for the diagnosis of the significance of concentration polarization in a specific permeation process, although it is difficult to predict concentration polarization accurately due to limited knowledge of the detailed membrane structure.