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Membrane solutions for energy efficient separations www.ecn.nl
Hydrothermal stability of a new hybrid membrane in dehydration applications
Jaap Vente
Membrane solutions for energy efficient separations www.ecn.nl
Approach
Four way competences:� Materials research� System development� Process design� Implementation facilitation
Five different lines of applications� Pervaporation� NH3 separation� Oxygen production� Hydrocarbons separations� Hydrogen purification
Membrane solutions for energy efficient separations www.ecn.nl
Why dehydration with membranes?
By 2015 potential energy savings:� NL: 7 PJ/yr (2% of industrial energy consumption)� World: 240 PJ/yr
Production of e.g. � Esters and resins� Methyl ethyl ketone (MEK)� Ethanol� Ureum� Acrylic acid
Membrane solutions for energy efficient separations www.ecn.nl
Industrial performance demands
Standard ECN tests: 5 wt.% water in butanol
Fluxes 5 kg/m2hSelectivity > 220Longevity 2 - 3 years
Conditions:Various pHTemperatures up to 150°C
Membrane solutions for energy efficient separations www.ecn.nl
Tubular microporous membranes
4 nm pores
120 nm pores
Pores < 1nmZrO2/TiO2
1000 nm
Membrane solutions for energy efficient separations www.ecn.nl
Materials covered
Previous developments:� SiO2
� Methylated SiO2
New leads:� TiO2
� ZrO2
� Hybrid silica, organic bridges
(Ceramic supported polymers)
Membrane solutions for energy efficient separations www.ecn.nl
SiO2 – Me-SiO2 pervaporation results (95ºC)
5 wt.% H2O in BuOH, 10 mbar
Addition of MTES gives better performance with time
Constant performance possible for over 18 months!
Published data Chem.Comm.2004, 834-835
8
6
4
2J H2O
/kg
h-1 m
-2
5004003002001000t/d
SiO2 1 step Me-SiO2
10% MTES 30% MTES
101
102
103
104
�
5004003002001000t/d
Membrane solutions for energy efficient separations www.ecn.nl
SiO2 – Me-SiO2 pervaporation up to 165ºC
• single step Me-SiO2
• 2.5 wt.% H2O in BuOH, 10 mbar• Failure within weeks• No clear relation with temperature
16
12
8
4J H2O
/ kg
h-1
m-2
)
403020100t/d
115°C 135°C 165°C
4
3
2
1
J BuO
H /
kg
h-1m
-2)
403020100t / d
Membrane solutions for energy efficient separations www.ecn.nl
Membrane surface after testing (Me-SiO2)
Severely damagedDense white particlesMany pinholes
Illustrative example (Me-SiO2, 135°C, 7 days)
Membrane solutions for energy efficient separations www.ecn.nl
Pore size distribution new membranes
Permporometry with H2OSuitable for thin toplayers
All membranes similar
N2 and mercury adsorption methods are for bulk material,not for thin layers!
1.0
0.8
0.6
0.4
0.2
0.0
Nor
mal
ised
per
mea
nce
43210Kelvin diameter (nm)
Methylated Silica Bridged Silica Zirconia Titania
Membrane solutions for energy efficient separations www.ecn.nl
Pervaporation with zirconia membrane
95°C, n-butanol/H2O (95/5%)Flux decline, but stable after 20 daysOperating for at least 120 days
5
4
3
2
1
0
J H2O
(kg.
m-2
.h-2
)
120100806040200Time (days)
100
90
80
70
Wat
er c
onte
nt p
erm
eate
(%)
Membrane solutions for energy efficient separations www.ecn.nl
Hybrid membranes from bisfunctional silica precursors
replacing Si—O—Si bonds by Si—C—C—Si bonds
(OC2H5)3 – Si – CH2 – CH2 – Si – (OC2H5)3
(bis(triethoxysilyl)ethane, BTESE)
Patented in collaboration with Univ. of Twente and Univ. of Amsterdam (Ashima Sah, Andre ten Elshof, Hessel Castricum, Marjo Mittelmeijer)
Membrane solutions for energy efficient separations www.ecn.nl
New membrane materials: Hybrid membranes
Mix in EtOH
Water, HNO3 , EtOH Reflux at 60ºC, 3 hrs
Mix
MTES
BTESE
Coating and calcination
Membrane solutions for energy efficient separations www.ecn.nl
Performance hybrid membranes (1) (150ºC)
Feed: 5% H2O in BuOHT = 150 C
100
95
90
85
80
75
70
Wat
erco
nten
t in
the
perm
eate
(%
)6004002000
Time on stream (d)
25
20
15
10
5
0
Wat
er fl
ux (
kg/m
2 h)
6004002000Time on stream (d)
Me-SiO2 stability
Membrane solutions for energy efficient separations www.ecn.nl
SiCH 3
-Si
-Si-C
H 2CH 2
-Si
<2d2w
2y
Hydrothermal stability at 150ºC
Time
Membrane solutions for energy efficient separations www.ecn.nl
Performance hybrid membranes (2) (190ºC)
Feed: 2,5% H2O in BuOHT = 190 C
12
11
10
9
8
7
6
5
Wat
er fl
ux (
kg/m
2 h)
35302520151050Time on stream (d)
100
98
96
94
92
90
Waterconcentrate in the perm
eate (%)
Membrane solutions for energy efficient separations www.ecn.nl
Performance hybrid membranes (3)
Water flux and conc. in permin different solvents
0
2000
4000
6000
8000
10000
MeOH EtOH PrOH BuOH MEK THF AcNi NMP
Solvents
Flux
(g/m
2 h)
0
20
40
60
80
100
Wat
er in
pe
rm. (
wt.%
)
Water fluxWater conc. in permeate
Feed = 5 wt.% water in solvent
Membrane solutions for energy efficient separations www.ecn.nl
Origins of stability
� More stable bonds� Higher crack propagation
energy� Lower surface diffusion
coefficient� Lower solubility
Membrane solutions for energy efficient separations www.ecn.nl
Hybrid membrane in the press
Chem Tech
NRCChem EngineeringMIT Tech ReviewChem Processing
Control & Automation Magazine
C2W Tech Weekblad
Over 1700 hits on Chem Commun in February 2008 alone!
Petrochem
Membrane solutions for energy efficient separations www.ecn.nl
Next steps
• FOCUS: IMPLEMENTATION
•State of the art membrane� Determine application window pH, H2O content, solvents� Create consortium for commercialisation: end user(s),
membrane producer(s), system integrator(s), supplier(s) enabling parts.
� Definition launching application(s).
• Further development:� Reduce pore size: H2O-EtOH, and hydrogen separation� Increase pore size: nanofiltration
Membrane solutions for energy efficient separations www.ecn.nl
AcknowledgementsThe MST group at ECN
Universities of Twente and Amsterdam:Hessel Castricum, Andre ten Elshof, Ashima Sah, Marjo Mittelmeijer-Hazeleger
Financial support:STW, SenterNovem
Membrane solutions for energy efficient separations www.ecn.nl
Thank you for your attention
For more information please contact me:
vente@ecn.nl+31 – 224 56 4916
www.ecn.nl
Membrane solutions for energy efficient separations www.ecn.nl
Chem. Commun., 2008, 1103 - 5, DOI: 10.1039/b718082aJ. Mater. Chem., 2008, 18, 2150 - 8, DOI: 10.1039/b801972j J. Sol-Gel Sci Techn, 2008, DOI: 10.1007/s10971-008-1742-zJ. Mem. Sci, 2008, in preparationPLUS MORE TO COME!
Patent: WO2007081212
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