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Lumen mass transfer in hollow‐fiber membrane processes with constant external resistances
Author(s) -
Qin Yingjie,
Cabral Joaquim M. S.
Publication year - 1997
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.690430807
Subject(s) - countercurrent exchange , mass transfer , mass transfer coefficient , lumen (anatomy) , mechanics , laminar flow , chemistry , constant (computer programming) , membrane , conservation of mass , hollow fiber membrane , thermodynamics , materials science , analytical chemistry (journal) , chromatography , physics , surgery , biochemistry , computer science , programming language , medicine
Hollow‐fiber membrane processes with a constant external resistance having a constant or variable shell concentration resulting from an operational mode of cocurrent or countercurrent are studied. By solving numerically the continuity mass‐conservation equation with the corresponding boundary conditions, the lumen laminar mass‐transfer coefficients for both cases are correlated. The correlations greatly improve the calculating accuracy of the overall mass‐transfer coefficient and can be used to obtain the lumen mixed‐cup concentration by an algebraic equation substituting the partial differential equation. A separation factor m' is introduced to characterize the effect of the operational mode. Calculation results demonstrate that the lumen mass‐transfer coefficient is independent of the real lumen and shell concentrations, but it is greatly influenced by m'. The countercurrent mode, compared to the cocurrent mode, provides not only a higher mean driving force, but a higher lumen mass‐transfer coefficient. This conclusion is novel and valid for the tube‐shell heat or mass‐transfer processes and is supported by the experimental data in the literature and our gas membrane separation experiments.