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Mechanisms of brine‐side mass transfer in a horizontal reverse osmosis tubular membrane
Author(s) -
Derzansky Lewis J.,
Gill William N.
Publication year - 1974
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.690200417
Subject(s) - laminar flow , concentration polarization , reverse osmosis , turbulence , mass transfer , mechanics , brine , membrane , chemistry , forced convection , desalination , convection , thermodynamics , chromatography , physics , biochemistry
The desalination performance of a tubular reverse osmosis membrane was studied under well‐defined hydrodynamic conditions. Experimental measurements were made of local mass transfer rates in a 2.31‐cm I.D. × 81‐cm long horizontal cellulose acetate membrane at 16 locations along the tube length for both laminar and turbulent flows. The membrane's intrinsic permeability to water and NaCl was found to vary significantly along its productive length. The experiments suggest that the dominant transport mechanisms in laminar flow are forced convection in the upstream region and combined free and forced convection in the downstream region, beyond a distance of approximately 16 tube diameters, for all feed concentrations studied. The Deissler analogy applies well to the turbulent region for Re ≧ 10 4 ; however, it increasingly overpredicts performance as Re is decreased below 10 4 . The experimental results of other workers are interpreted successfully in terms of the mechanisms deduced in the present work.