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@PHDTHESIS{Hagemann:837978,
author = {Hagemann, Franziska Maria Dorothee Gertrud},
othercontributors = {Wessling, Matthias and Boi, Cristiana},
title = {{M}odel based design and optimization of high capacitive
membrane adsorbers},
volume = {23 (2022)},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2022-00218},
series = {Aachener Verfahrenstechnik series - AVT.CVT - chemical
process engineering},
pages = {1 Online-Ressource : Illustrationen, Diagramme},
year = {2021},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University 2022; Dissertation, Rheinisch-Westfälische
Technische Hochschule Aachen, 2021},
abstract = {In order to isolate cell derived target molecules from the
respective fermentation broth, faster and more efficient
unit operations are required. Due to mass transfer
limitations, resin chromatography typically shows a strong
dependence of the binding capacity on the residence time and
is therefore limited in separation velocity. Small particles
cause thinner convective channels and therefore create a
higher pressure drop over the chromatographic bed.
Convective chromatography e.g. based on membranes, is a
promising approach, representing nearly residence time
independent separation processes with respect to the binding
capacity, yielding high process productivity. Due to the
inherent structural properties of purely convective
separation media, the specific surface area and thus the
binding capacity often become limiting factors. Membrane
adsorbers with a biporous structure can improve the
downstream process in bioprocesses, because mass transfer
limitations are drastically reduced compared to conventional
resin chromatography materials. Convective pores enable fast
mass transfer and diffusive pores in the membrane bridges
provide surface for binding. The diffusive pathways in
membranes are much smaller than conventional bead diameters,
allowing higher flow rates in the process. The aim of this
thesis is the model based optimization of such membrane
adsorbers. The membrane is optimized regarding bed height,
convective porosity, permeability, diffusive pore structure
and the length of diffusive pathway. The impact of the
target molecule size and the flow rate are taken into
account.The diffusive pore structure was modeled with a
cubic grid model, which provides information of the pore and
filament diameters. Pore diffusion coefficients were
determined using the general rate model. Due to the large
diameter to bed height ratio of membrane adsorbers, the
adequate flow distribution is very important. Therefore,
residence time distributions (RTD) of the devices were
investigated using CFD simulations. The impact of bed height
and dead volume in the devices was analyzed. Moreover, the
influence of the housing and the membrane on the RTD of the
total device were separated using CFD simulations. It was
possible to simulate experimentally obtained membrane
adsorber breakthrough curves with a modification of the
general rate model. This model was used to determine
productivities of different potential membrane adsorber
configurations. The process productivity is increased by the
factor of 90 for an optimized membrane adsorber compared to
conventional state of the art resin processes, assuming an
ideal flow distribution. The current status membrane
material is already 22 times better than the resin process.},
cin = {416110},
ddc = {620},
cid = {$I:(DE-82)416110_20140620$},
typ = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
doi = {10.18154/RWTH-2022-00218},
url = {https://publications.rwth-aachen.de/record/837978},
}
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