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Oxygen transfer in mechanically agitated aqueous systems containing dispersed hydrocarbon
Author(s) -
Hassan Ibrahim T. M.,
Robinson Campbell W.
Publication year - 1977
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260190505
Subject(s) - aqueous solution , hydrocarbon , chemistry , dodecane , hexadecane , aqueous two phase system , oxygen , phase (matter) , volume (thermodynamics) , mass transfer coefficient , ionic strength , fraction (chemistry) , analytical chemistry (journal) , chromatography , mass transfer , thermodynamics , organic chemistry , physics
Abstract The effect of dispersed n ‐dodecane or n ‐hexadecane on the air‐to‐aqueous phase overall volumetric oxygen transfer coefficient in a simulated (cell‐free) stirred‐tank fermentor is described. The oil volume fraction ranged from zero to 0.10; the ionic strength of the aqueous phases was varied from 0 to 0.45. The air‐to‐aqueous phase coefficients in both oil‐free ( K L a ) and oil‐bearing ( K L a *) systems were evaluated from unsteady‐state experiments using a membrane‐covered probe to follow the aqueous phase dissolved oxygen tension. For all systems studied, K L a */ K L a was found to be independent of P / V and v s for all practical purposes. However, for a particular aqueous phase and at a given P / V and v s , the ratio K L a * K L a generally differed from unity. Depending on the combination of hydrocarbon type and volume fraction and the aqueous‐phase ionic strength employed, the dispersed hydrocarbon may, in some cases, reduce the rate of oxygen transfer and in others enhance it relative to that of the corresponding oil‐free gas–liquid dispersion. Enhancement of the air‐to‐aqueous transfer rate by such negative spreading coefficient hydrocarbons has not been reported previously.