Premium
Mass transfer across mobile interfaces
Author(s) -
Angelo J. B.,
Lightfoot E. N.
Publication year - 1968
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.690140403
Subject(s) - mechanics , mass transfer , drop (telecommunication) , tray , residence time distribution , flow (mathematics) , chemistry , thermodynamics , physics , mechanical engineering , engineering
The dependence of extraction efficiency on flow distributions and droplet boundary‐layer behavior was investigated in a specially designed sieve‐tray extractor. Flow patterns and drop trajectories were obtained from residence‐time distributions and photographic observation. Extraction efficiency and continuous phase residence times were determined by a pulse technique. For most runs, flow behavior could be adequately described by the assumptions of perfect mixing in the continuous phase and plug flow of the drop phase. However, drop velocities were higher than predicted by single drop correlations, and the flow pattern was sensitive to minor changes in operating conditions. Observed extraction efficiencies were in good agreement with predictions based on observed flow patterns and the two film, surface stretch, mass transfer model of Angelo and Lightfoot. Approximately 90% of the stage mass transfer effectiveness appears to be due to the drop rise period, and essentially all the remainder to drop formation for the stage geometry selected. The greatest obstacle to reliable prediction of extractor performance is uncertainty as to the effect of operating conditions on flow distribution.