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

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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

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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

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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

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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

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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

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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

Next step: 1m2 field test

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