EP0077528B1 - Refined edible oil and process for its preparation.pdf
Membranes preparation - Demcamer - Membrane preparation.pdf · Critical thickness to obtain a dense...
Transcript of Membranes preparation - Demcamer - Membrane preparation.pdf · Critical thickness to obtain a dense...
CARENA processes and membranes
H2 selective membranes: - Pd based membranes - Dense ceramic membranes
O2 selective membranes: - Dense ceramic membranes
H2O selective membranes: - Polymer based membranes - Hybrid membranes - Microporous membranes
Content
• Pd based membranes
• Dense ceramic membranes
– Oxygen selective membranes
– Hydrogen selective membranes
Pd-alloy membranes
Pf
Pd-alloy
H N N
N N
N
N N
H
H H
H H H H
H
H H H H
H
H H
N N
Pp
thickness dP
EU-7FP CACHET-II project (Contract no.: 241342)
EU-7FP CARENA (Contract no.: 263007)
RCN-Renergi and CLIMIT (Project No: 190779/S60)
Pd based membranes
Activities in CARENA beyond SOA:
• Understanding degradation mechanisms
• Manufacturing technology for scaling up production of Pd membranes
• Testing of "real performance"
• Coking resistance
HIGH FLUX; LARGE EXPERIENCE in consortium; reliable assessment of performance Current status: coking issue; flux in low partial pressure difference? Benefit for higher T ?
Fabrication and design
Electroless plating
Sputtering
Electroplating
MOCVD/CVD/PVD
Spray pyrolysis
Wet impregnation
….
Most methods manufacture the dense Pd layer directly on the support
Critical thickness to obtain a dense metal layer which depends on surface roughness and pore size in support’s top layer
High support quality: narrow pore size distribution + no surface defects
Pd-alloy fabrication methods
Interdiffusion barrier
Porous stainless steel or ceramic support
Pd-based membrane
Materials and Chemistry 7
SINTEF two-step membrane preparation
Pd-Ag target
Pd-Ag membrane
Ar-ions
Pd +Ag Pd +Ag Membrane preparation
on Si support by
magnetron sputtering
Membrane pull-off
from Si support
a) Free standing
membranes
b) Microchannel
supported
membranes
c) Composite membrane
1
2
high vacuum
Bredesen R, Klette H,
US Patent 6086729, 2000
(a)
(b)
(c)
Materials and Chemistry 8
Tubular Pd-alloy membrane manufacturing
Deposition of thin Pd-
alloy film on silicon wafer
Membrane pull-off
from Si support
Application on
porous support
Lab-scale composite
membrane preparation
50 cm up-scaled
membranes
Materials and Chemistry 9
Membrane and module design used in CARENA for "real
testing"
Pd-Ag films supported on micro-channels: reduction of polarisation resistance
Channels / slits between 0.2 and 1mm
No influence of permeate support side
High membrane area relative to the gas volume
Limiting effect of concentration polarisation
A.L. Mejdell, M. Jøndahl,
T.A. Peters, R. Bredesen,
H.J. Venvik., J. Membr.
Sci., 327 (2009) 6-10.
SEM: large plastic deformation shows
the high mechanical strength
Depth channels:
28 m
Film thickness:
~2 m
Materials and Chemistry 10
Co-sputtering enables to prepare various geometries and scales
Pd
Pd-Cu
Pd-Au
Pd-TM
Pd-Cu-TM
Pd-Au-TM
Co-sputtering enables to prepare binary and ternary alloy composition
Flexibility of manufacturing …
EDS [wt.%] Pd Ag Cu
Pd-Cu-Ag1 70.6 14.5 13.9
Pd-Cu-Ag2 66.6 14.3 19.1
Pd-Cu-Ag3 61.4 12.7 25.9
Pd-Cu-Ag4 58.0 11.7 30.3
Pd-Cu-Ag5 48.0 10.7 41.3
Materials and Chemistry 11
XRD: example of Pd-TM alloy membranes
FEG-SEM: Element mapping of cross-section of Pd72Cu25Au3
… for tuning of properties
Single phase fcc structure
No contaminant observed
Strong preferential orientation in
<111> direction
TM is substituting Pd in the fcc
lattice: unit cell varies and H2
solubility and diffusivity too
Homogeneous distribution of
metal components
Peters, T.A., et. al., J. Membr. Sci., 383, 2011, 124.
Summary 1
• Pd-based membranes fabricated by sputtering
– Thin membranes with high mechanical strength
– Various alloy compositions available
• Design of membrane module
– Tubular membranes for scaling up
– Micro- channels for real testing conditions
Ceramic conducting membranes
CH4 +
H2O
H2O+
CO2
Air
N2 + H
2O
+ H2
4 e-
4 H+
Catalyst
Membrane
2O2–
4e–
Permeate side: Low p(O2)
Feed side: High p(O2)
Membrane
Hydrogen transport membranes Oxygen transport membranes
EU FP7 ICAP
EU-7FP CARENA (Contract no.: 263007)
BIGCCS
H2 transport membranes
Activities in CARENA beyond SOA:
• New HTM materials
• Testing symmetric membranes in relevant conditions
• Shaping and scalability of membrane production considered
High stability at high T; not (less) sensitive to coking than Pd based membranes; High flux and high stability difficult to achieve Current status: button cell samples; Reference: SrCe1-xYxO 3 perovskite membranes
Fabrication and design
O2 transport membranes
Activities beyond SOA: • Materials development
• Manufacturing processes: scalability?
• Advanced characterisation tools
High flux membranes at T > 750C; Scalability of OTM membranes done by 2 large consortia in USA ; long term stability of high flux membranes problematic due to cation diffusion + stability in C containing atmosphere Current status : search for high flux membranes and fabrication of thin films
Fabrication and design
HTM: mainly small disk shaped membranes
Statoil: OTM
module
Air Products:
OTM module
SINTEF
OTM) scaled up production
SINTEF
8-10 microns
10 cm length (9 mm diameter)
50 microns
Statoil
Status of development
– Dense layer: lower L higher flux
– Porous support: no pressure drop
– Surface area as large as possible: improved kinetic exchanges
Requirements for membrane preparation
Wet ceramic coating and submicron-sized powders
Use of pyrolyzable fillers
Small grains; use of porous catalytic layers
22ln
16
2ln
2ln
2 O
ionel
ionelO p
LF
RTJ
IIOp
IOp
Membrane by tape-casting
Co-lamination @ T and P
Asymmetric membrane (one side polished)
Sintering procedures
Sintering
Support by tape-casting
Lamination @ T and P
Annealing
Spray-, dip- or spin-coating
Asymmetric membrane
Sintering procedures
Sintering
Suspension
Enable thin membranes
Controlled thickness typically > 20 microns
Enable optimization of supports
Planar membrane fabrication (OTM and HTM)
Support without filler
porosity = 50% porosity = 11%
Spin coating
m
Support with 5 % starch
Support with 5 % starch
porosity = 50%
Tape-casting
m
Planar membrane fabrication (e.g. OTM)
20
Effects of supports
Thickness of the selective layer = constante = ~30 microns
0,0E+00
2,0E-04
4,0E-04
6,0E-04
8,0E-04
1,0E-03
1,2E-03
1,4E-03
1,6E-03
1,8E-03
0,75 0,8 0,85 0,9 0,95
1000 T-1
/ K-1
P (
mL
.cm
-1.m
in-1
)
Support: 5% starch
Support: 10% ammonium oxalate
Support: 7.5% ammonium oxalate
Support: no filler
Ea ~ 47.5 kJ.mol-1
Feed:Air
Permeate: Ar
Ramp: 60 ºC/h
Ea ~ 53.8 kJ.mol-1
On the preparation of asymmetric membranes by tape-casting and co-sintering process, Journal of Membrane Science, Volume 326, Issue 2, 20 January 2009, Pages 310-315 M.-L. Fontaine, J.B. Smith, Y. Larring, R. Bredesen
Tubular membrane fabrication (OTM and HTM)
Paste preparation Extrusion of tubes Coating and sintering: membrane length max 1m
Support
Ceramic powder
Binder solution
Miller: several kgs
of feedstock
Ram extruder
Paste
Asymmetric sintered membrane of La0.87Sr0.13CrO3
10 microns
Dip-coating of tubes
Sintering
Membrane preparation at SINTEF (OTM and HTM)
Conditioning
Additives: fillers
Milling
Additives: water, dispersant, binder,
lubricant etc…
Mixing
Extrusion
Drying of samples
Porous supports
Suspension: oxide, solvent, dispersant,
binder
Mixing
Dip-coating, spray-coating
Sintering
Asymmetric membranes
SUPPORT FABRICATION COATING and SINTERING OF DENSE LAYER
Quality check
Quality check
Annealing T < 1300°C
Quality check
ASYMMETRIC MEMBRANES
Commercial powders
Starches Chitosan Tapioca …
SINTEF binder solution
Rheology of paste
Specific surface area (BET)
Dilatometry analysis: TEC, annealing
treatment
Hg porosimetry
Gas permeation
White light interferometry:
topography Microscopy
(SEM; FEG SEM)
X-ray diffraction (in situ): structure
Laser diffraction : particle size distribution
Potential zêta
Characterization &
QA of products
• Several green fillers available
• Thermal decomposition in air at low temperature with no residue
• No need for various conditioning steps of the ceramic powders
• No need of asymmetric structure of the support
• Fairly direct control of pore volume, pore shape and distribution
23
Pore formers (PF)
24
24
Agar agar
Ammonium oxalate
Chitosan
PF→ paste rheology →
extrusion parameters →
quality of supports
Support's porosity → gas
flow + roughness
Coating → quality (defects),
thickness 15 microns
< 10 microns
8-10 microns
10 cm length (9 mm diameter)
Advantages of using pore formers
• Small pores of less than 1 microns due to partial sintering of grains
• Volume adjusted by sintering treatment and green density
• Large pores of 5 to 10 microns (or more) due to burnout of fillers
• Volume adjusted by filler content in green state
Corn starch
Two main distributions of pores:
Microstructure and roughness
Surface of the tubes
explored by white
light interferometry
Rheology of pastes
strongly affected by
pore former content:
complex system
Roughness of the
tubes
Pores due to
burnout of
pyrolyzable
fillers
Pre-annealed porous tube:
Average roughness: 2,27 µm
Coating
Good coverage of
large pores
Porous tube coated and sintered:
Average roughness: 210 nm
Coating
Impurities (Mg, Al) rich particle
Crack
Thickness ~38 µm
Thickness ~24 µm
Thickness ~12 µm
Same porous supports
Presence of impurities: Leakages Cracks due to different
thermal expansion Effect more severe for
thinner films: clean room needed
22ln
16
2ln
2ln
2 O
ionel
ionelO p
LF
RTJ
IIOp
IOp
Impurities versus performance
Air
O2 g
Leakage
Decrease in the oxygen partial pressure gradient
Decrease in the oxygen flux +
Dilution with nitrogen
N2 g