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A Rigorous Model for Annular Chromatography
Author(s) -
Brozio J.,
Bart H.J.
Publication year - 2004
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.200402077
Subject(s) - dispersion (optics) , annulus (botany) , radius , mechanics , chemistry , optics , chromatography , materials science , physics , composite material , computer security , computer science
Modeling of annular chromatography is refined to incorporate the influence of axial and annular dispersion. Annular and axial dispersion coefficients are measured simultaneously in an annular chromatograph using an experimental technique based on the introduction of a non‐adsorbable tracer. The annular dispersion coefficient is found to be one order of magnitude lower than the axial one. Nevertheless, annular dispersion has a more pronounced effect on total dispersion when steep concentration profiles are present. A criterion to judge whether annular dispersion is negligible is developed. If the circumferential velocity is at least 0.88 times higher than the interstitial velocity, lateral dispersion can be omitted. Based on this criterion it can be concluded that the impact of annular dispersion decreases with the radius of the annulus. Therefore, it is preferable to build annular chromatographs with a large radius and a thin annulus rather than using a small radius and a thick annulus.