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@PHDTHESIS{SchulzeKppers:19317,
author = {Schulze-Küppers, Falk},
title = {{E}ntwicklung geträgerter
{B}a$_{0,5}${S}r$_{0,5}${C}o$_{0,8}${F}e$_{0,2}${O}$_{3-\delta}$
{S}auerstoff-{P}ermeationsmembranen},
volume = {126},
school = {Universität Bochum},
type = {Dr. (FH)},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {PreJuSER-19317},
isbn = {978-3-89336-752-8},
series = {Schriften des Forschungszentrums Jülich : Energie $\&$
Umwelt / Energy $\&$ Environment},
pages = {II, 119 S.},
year = {2011},
note = {Record converted from VDB: 12.11.2012; Universität Bochum,
Diss., 2011},
abstract = {Oxygen Transport Membranes (OTMs) are a promising way of
obtaining high-purity oxygen. Compared to conventional
methods, membranes require less energy than cryogenic air
separation. OTMs consist of gastight, ceramic, mixed
ionic-electronic conductors (MIEC) and allow oxygen
transport via oxygen vacancies in the crystal lattice.
Therefore, the theoretically achievable purity of these OTMs
is $100\%.$ The most promising class of materials are the
perovskites, which has a high ionic and very high electronic
conductivity. The perovskite with the highest oxygen
permeability is the
Ba$_{0,5}$Sr$_{0,5}$Co$_{0,8}$Fe$_{0,2}$O$_{3-\delta}$
(BSCF), which has also been used in this work. Further
potential for improvement of the oxygen permeation can be
provided by a thin, supported membrane,an optimization of
the microstructure of the porous support as well as by the
use of porous activation layers on top of the membrane. An
aim of the first part of the work is the development of thin
membranes on top of a porous support. For this purpose,
supports of different porosity and pore size were prepared
by tape casting using different pore formers. The thin
membrane layers were manufactured by screen printing and
tape casting. The preparation of screen-printed membrane
layers as well as porous activation layers was carried out
on pre-sintered supports respectively sintered membranes.
Composite membranes (thin membrane layer and porous support)
were prepared by sequential tape casting and subsequent
co-firing. Regarding deflection and leakage, the tape cast
and co-fired membranes achieved the best results. The
influence of membrane microstructure on oxygen permeation
has been studied on composite membranes with 26\%, 34\% and
41\% support porosity and 20$\mu$m and 70$\mu$m membrane
layer thickness. This increase of support porosity as well
as the reduction of membrane thickness led to an increase in
the oxygen permeation. The increase of the oxygen permeation
by decreasing the membrane layer thickness is lower than the
Wagner equation would have suggested and this issue will be
discussed in this chapter. Ways of reducing the limiting
factors are to be sought in the use of porous surface
layers, tailoring the support microstructure and in the use
of vacuum conditions instead of a sweep gas on the support
side. Limiting factors for oxygen transport through the
composite membrane were identified and separated by
systematic choice of the boundary conditions during
permeation measurements. Limiting factors are surface
transport processes, concentration polarization in the
porous support and the transport through the membrane. From
the acquired data, a transport model has been developed to
describe the oxygen transport through the composite
membrane.},
cin = {IEK-1},
cid = {I:(DE-Juel1)IEK-1-20101013},
pnm = {Rationelle Energieumwandlung},
pid = {G:(DE-Juel1)FUEK402},
typ = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
url = {https://juser.fz-juelich.de/record/19317},
}