ISSN:
0178-515X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract During the bioconversion of tetralin in the liquid-impelled loop reactor, oxygen and tetralin are transferred from the organic-solvent phase to the aqueous phase. Mass transfer of either tetralin or oxygen is likely to be the rate-limiting step in this bioconversion. In order to establish which of the two is limiting, the overall mass-transfer coefficients (K i,L A) of both substrates were determined. Theoretical calculations did not reveal large differences. Therefore both K i,L A’s were experimentally determined as well. From the results it is concluded that neither tetralin nor oxygen can be assigned to be the mass-transfer-limiting factor if tetralin is completely converted into CO2 and H2O. On the other hand, if tetralin is oxidized only partly (the aim of our synthetic studies), it very likely is the limiting substrate and process control can thus be achieved by controlling the supply of this toxic compound. List of Symbols ρ S kg/m3 solvent density vs m/s slip velocity of the drops=vs S /a−vs L /(1−a) vs S , vs L m/s superficial velocity of the organic-solvent phase and the aqueous phase, respectively, in the main tube of the LLR a– holdup of organic-solvent phase in the main tube of the LLR d m drop diameter n S Pa s dynamic viscosity of the organic-solvent phase D L m2/s diffusion coefficient of solute in the aqueous phase Re L – Reynolds number of the aqueous phase around the drops ρ L vs dη L ρ L kg/m3 density of the aqueous phase η L Pa s dynamic viscosity of the aqueous phase Sc L – Schmidt number of the aqueous phase=η L /ρ-1 L D L g m/s2 gravitational acceleration F– correction factor for the circulation within the droplets σ N m interfacial tension D S m2/s diffusion coefficient of solute in the organic-solvent phase t s time of contact B n – coefficient λ n –nth eigen value
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00387696
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