STUDIES OF LIQUID PHASE MIXING AND BED EXPANSION OF GAS PRODUCING ANAEROBIC FLUIDIZED BED BIOREACTOR
STUDIES OF LIQUID PHASE MIXING AND BED EXPANSION OF GAS PRODUCING ANAEROBIC FLUIDIZED BED BIOREACTOR
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Date
1992
Authors
YAMMAMA, ABDURRAHMAN GARBA
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Abstract
ABSTRACT
Liquid phase mixing and holdup are two important
parameters required for the modelling and consequent
evaluation of the performance of anaerobic fluidized bed
bioreactors. Few papers have appeared in recent times,
attempting to characterize liquid phase mixing and holdup
in simulated biological reactors. But, the peculiar nature
of biological systems as regards in situ gas production,
which is difficult to simulate, mean that results from
simulated studies need to be verified against active
biological system. One of the problems hindering this
verification is finding suitable tracer for use, in
determining the axial liquid dispersion coefficient, with
microbial system.
In this work, the effects of superficial liquid and
gas velocities in the ranges 0.0084 to 0.0351 cm/s and
0.054 to 0.335 cm/s respectively, on axial liquid
dispersion coefficient (D2) and liquid holdup (eL), were
studied in an anaerobic column bioreactor, of 3.81 cm
internal diameter, containing flocculent strains of
Saccharomyces cerevisiae. The strains used are Y6 and NCYC
1026. The gas velocities were calculated from the ethanol
concentrations and were varied by varying the glucose feed
rate. Since D and eL were determined from the liquid
residence time distribution, a search for a tracer
suitable, for use with the yeast, was conducted. In
addition the performance of the bioreactor was studied
under the same liquid and gas flow conditions.
Five tracers, methyl violet, methyl green, aniline
blue, fluorescein and dextran blue, were tested at three
stages. In the first stage, shake flask fermentations were
performed. Methyl violet was found to affect yeast
metabolism by hindering it while methyl green promoted
yeast metabolism. These tracers were also partly lost due
to adsorption on cells surfaces. Fluorescein, aniline blue
Description
A Dissertation submitted in partial fulfillment of the
requirements for the degree of Doctor of Philosophy
Chemical and Process Engineering Department
University of Strathclyde, Glasgow
Keywords
STUDIES, LIQUID PHASE, MIXING, BED EXPANSION, GAS PRODUCING ANAEROBIC, FLUIDIZED BED BIOREACTOR