1

Yuichi FujiokaYuichi FujiokaRITERITE (R(Research Institute of esearch Institute of IInnovativennovative TTechnology for the echnology for the EEartharth))

Development of Innovative gas separation membranes through sub-nanoscale materials

control

Development of Innovative gas separation membranes through sub-nanoscale materials

control

GCEP Research Symposium 2008GCEP Research Symposium 2008Friday, October 3, 2008Friday, October 3, 2008Carbon Capture and Storage Carbon Capture and Storage

2

OutlineOutlineOutline

1. Background

2. Our previous researches

3. Researches in this year

Carbon membrane

PAMAM dendrimer / mesoporous silica membrane

3

CCSin Ocean

in Deep aquifer

in depleting oil and gas reservoirs

Technological Options for 550 ppmv Stabilization

Technological Options for 550 ppmv Technological Options for 550 ppmv StabilizationStabilization

｢再生ケース｣におけるCO2正味排出量

0

5

10

15

20

25

2000 2010 2020 2030 2040 2045 2050 2060 2070 2080 2090 2100

Energy Saving

Fuel Switching

BiomassSolar CellsWind PowerHydro. and GeothermalNuclear power

Reforestation

2000 2010 2020 2030 2040 2045 2050 2060 2070 2080 2090 2100(Year)

25

[Gt-C/y] [Gt-CO2]92

73

37

6.8

Car

bon

emis

sion

s an

d re

duct

ions

Without CO2 Mitigation Policy

The CO2 Emission Level is Requested to Stabilized CO2 550ppmv

CO2 reduction by Various technologies

RITE (1997)

4

Carbon Capture and Storage (CCS)Carbon Capture and Storage (CCS)

TransportCO2 Capture Injection

Offshore aquifer

Large scale emission source

CO2

Pipeline / Ship

5

Estimation of CO2 capture energyEstimation of CO2 capture energy

CO2 capture using chemical absorption

Pulverizing coalpower plant A chemical absorption

consumes 80% of total energy in CCS system.

CC

S a

t Pul

veriz

edco

al p

ower

sta

tion

6

Application membrane for CO2 separation

Application membrane for CO2 separation

Target: Less than 1 GJ / ton-CO2Separation factor > 100

Less than 20$ / ton-CO2CO2 Permeance > 1 x 10-8

CO2 capture using membrane

Pulverizing coalpower plant

Definition of Permeance & Separation factorCO2 permeance(QCO2): Ft·yCO2 / (p1·xCO2 - p2·yCO2) / AN2 permeance(QN2): Ft·yN2 / (p1·xN2 - p2·yN2) / ACO2/N2 separation factor(αCO2/N2) : (yCO2/yN2)/(xCO2/xN2) ≈ QCO2/QN2

x (-): molar fraction in feedy (-): molar fraction in permeatep1 (Pa): total pressure in feedp2 (Pa): total pressure in permeateFt (m3 s-1): total gas flow of permeateA (m2): membrane area

p1, xCO2, xN2

p2, yCO2, yN2

Feed

Permeate

Retentate

Membrane

7

H2 rich gas

>95%

Application of membrane for pressurized gases

Application of membrane for pressurized gases

CoalBiomass

H2 O

Natural gas

Heat exchanger

Composition: CO2 40 vol%/ H2 balanceTemperature: <150 °C for carbon membrane, 200 °C> for zeolite membranePressure: < 4 MPa

CO2 rich gas

>97%

GasifierorReformer

Water-Gasshift Reactor

CO2 separation membrane

8

1

10

100

1000

0.001 0.01 0.1 1 10 100

Zeolite T(Kita et al., 2004)

Na-Y(Kusakabe et al., 1997)

K-Y(Kusakabe et al., 1999)

Sapo-34(Falconer et al., 2000)

Silicalite(Ando et al., 1998)

Na,B,K-ZSM-5(Santamaria et al., 2004)

Cs/Na-Y(Kusakabe et al., 2002)

SiO2/ZrO2(JFCC, 2000)

Carbon(Kusakabe et al., 1998)

Anodic Al2O3(JFCC, 2000)

Cardo-polyimide(RITE)

APS/MS/Ai2O3(RITE)

Na-Y(RITE)

PAMAM/PSF(RITE)

CO2 Permeance x 10-9 [ m3 m-2 s-1 Pa-1 ]

Membrane performances in previous works

Membrane performances in previous works

Target

CO

2/

N2

9

2. Our previous researches including GCEP

10

Concept of “Molecular Gate” membraneConcept of Concept of ““Molecular GateMolecular Gate”” membranemembrane

: CO2：Other gas

AB

ABA

A

B

：CO2 affinity material

AA

, such as alkali metal carbonate, amine containing organic material and etc.

11

CO2 /H2 Separation by PAMAM dendrimerCO2 /H2 Separation by PAMAM dendrimer

Hydrophilic porous substrate

47mm

After supporting PAMAM dendrimer in Hydrophilic porous substrate

Cross section diagram of Membrane

Photo of Membrane

* A. S. Kovvali, H. Chen, and K. K. Sirkar, J. Am. Chem. Soc. 2000, 122, 7594-7595

N

ONH

NH2

ONH

NH2

N

OHN

H2N

ONH

H2N

PAMAM Dendrimer*

1) Selective LayerPAMAM Dendrimer

+ Hydrophilic porous substrate

2) Hydrophobic porous substrate

CO2 + H2 (Feed)

He (Permeate)

12

CO2 /H2 Separation by PAMAM dendrimerCO2 /H2 Separation by PAMAM dendrimer

QH2

QCO2

10 -14

10 -13

10 -12

10 -11

10 -10

10 -9

0 20 40 60 80 100Per

mea

nce

[ m3 (

STP

) m-2

s-1P

a-1]

Relative humidity in Feed Gas [ % ]

Feed: 100 kPa, CO2 / H2 = 5% / 95%, 298 K (25 °C) Permeate: 1 kPa

RH increaseCO2 permeance increaseH2 permeance increase

Duan, S., et al, J. Membr. Sci., 283, 2 (2006)

13

Suggestive mechanism of CO2 and N2 separation with PAMAM dendrimer membrane

Suggestive mechanism of CO2 and N2 separation with PAMAM dendrimer membrane

Before humidification After humidification

+

PAMAM H2 O Hydrate PAMAM

H2

RH > 60 %

RH increaseCO2 permeance increaseH2 permeance increase

CO2 H2 CO2

swelling

Gaps

Attractive forceRepulsive force

Swelling and Hydrophilic force makes agglomeration Hydrate PAMAM

14

Fixation PAMAM dendrimer on inside hollow fiber Fixation PAMAM dendrimer on inside hollow fiber

Hollow Fiber

Coating Solution

GlueSolution

Pump

Reduced Pressure

Membrane Module

Hollow Fiber

SupportingSubstrate

Chitosan

ReducedPressure

• Procedure for separating CO2 in difference pressures between feed side and penetrate side

15

Performances of PAMAM dendrimer / Chitosan composite membrane

Performances of PAMAM dendrimer / Chitosan composite membrane

MembraneQCO2

[ m3(STP)m-2 s-1 Pa-1 ]αCO2/N2

PSF-substrate(a) 2.3 x 10-7 1

Chi-substrate(b) 1.8 x 10-8 1

PAMAM dendrimer /

polymer composite4.6 x 10-10 230

(a): PSF hollow fiber membrane as dried (b): PSF-substrate with chitosan gutter layer

Feed : water saturated, CO2 /N2 = 5% / 95% of at 101 kPaPermeate: evacuated at 4 kPa.Temperature: 313 K

600 nm

Chitosan PolysulfonePAMAM dendrimer This PAMAM fixation method can apply

PAMAM membrane to gas separation at large pressure difference, such as between 100 kPa and 1 kPa.

Kouketsu, T., et al, J. Membr. Sci., 287, 51 (2007)

16

PAMAM Dendrimer density and Performances

PAMAM Dendrimer density and Performances

Taniguchi, I., et al, J. Membr. Sci., 322, 277-288 (2008)

N N

NH

NH

NH2

HN

HNO

O O

O

NH2H2N

H2Nn n

PAMAM dendrimer65432110nGeneration

OO

O

O

PEGDMA PAMAM dendrimer

Dendrimer in PEGDMA network

+UV

14

Cross-linked PEGDMA

17

1x10-17

1x10-16

1x10-15

1x10-14

1x10-13

0

100

200

300

400

500

600

0 10 20 30 40 50 60

PAMAM content [ wt%]

QCO2

QH2

α

PAMAM dendrimer effectsPAMAM dendrimer effects

PAMAM content

[%]

Permeance [m3(STP) sec-1 m-2 Pa-1]

CO2 H2

0 1.63x10-14 2.39x10-15

50 2.74x10-14 2.22x10-17

1.7 1/100

298 K 80% RH, Feed gas CO2 /H2 5/95 PAMAM enhanced CO2 permeation rate

18

Suggestive mechanism of CO2 and H2 separation with PAMAM / PEGDMA membrane

Suggestive mechanism of CO2 and H2 separation with PAMAM / PEGDMA membrane

H2 CO2

PAMAM dendrimerCross-linked PEGDMA

Content of PAMAM dendrimer: 0 20 50

H2 permeation rate : 1 1/10 1/100

CO2 permeation rate : 1 1 1.7

H2 CO2 H2 CO2

19

2.2 nm

Amino-modified mesoporous silica membrane

Amino-modified mesoporous silica membrane

0.8 nm

APS / MCM - 48MCM-48 (2.2 nm pore) is promisingCO2 = 0.33 nm

APS = 0.7 nm

MCM - 48

• Structure of membrane

APS: H2 N Si(OCH2 CH3 )3

3-aminopropyltrietoxysilane

Mesoporous silica layer Alumina substrate

Sakamoto, Y., et al, Microporous and Mesoporous Materials, 101, 303-311 (2007)

20

Result of amino-modified mesoporous silica membrane

Result of amino-modified mesoporous silica membrane

• High CO2 /N2 separation factor without H2 O• Amino-modified mesoporous silica membrane

10-15

10-14

10-13

10-12

10-11

1

10

100

1000

104

105

300 320 340 360 380 400 420 440

Temperature (K)

21

Attractive force by amino-function and CO2 separation

Attractive force by amino-function and CO2 separation

• Increasing temperature made CO2 and N2 permeance. CO2 permeance increased 100 times larger from 313 K to 353K.

It is supposes that decreasing CO2 attractive force by amino-function enhances CO2movement inside pores.CO2 molecules near amino function block out N2 molecules.

22

3. This year researches

Carbon membrane

PAMAM dendrimer / mesoporous silica membrane

23

CO2 /N2 Separation performance of carbon membrane

CO2 /N2 Separation performance of carbon membrane

CO2 /N2 : Separation factor: 7 - 101 1)

1) S. M. Saufi, A.F. Ismail, Carbon, 42 (2004) 241-259.

CO2 /N2 separation factors are in a wide range

Definition of Permeance & Separation factorCO2 permeance(QCO2): Ft·yCO2 / (p1·xCO2 - p2·yCO2) / AN2 permeance(QN2): Ft·yN2 / (p1·xN2 - p2·yN2) / ACO2/N2 separation factor(αCO2/N2) : (yCO2/yN2)/(xCO2/xN2) ≈ QCO2/QN2

x (-): molar fraction in feedy (-): molar fraction in permeatep1 (Pa): total pressure in feedp2 (Pa): total pressure in permeateFt (m3 s-1): total gas flow of permeateA (m2): membrane area

p1, xCO2, xN2

p2, yCO2, yN2

Feed

Permeate

Retentate

Membrane

24

Our approach to carbon membraneOur approach to carbon membrane

Incorporate CO2 affinity materials in the pores

→Enhanced CO2 permeation using adsorbed CO2 in the pores

Pore size: 0.5-5 nmCarbon

CO2 affinity materials

CO2

CO2

Mild connection

Concept• Building adequate bond between CO2 and CO2 affinity

material for CO2 separation

25

Membrane preparation procedureMembrane preparation procedure

Dipping to coat（Outer-surface）

Drying

Carbonization

Product

600 °C, 3h; Heating rate: 5°C/min

NMP solution with precursor

60 °C, >8h

Preparation of precursor solution Blending CeCO3 with polymer

26

Precursor-coated membrane Carbon membrane

Substrate: porous alumina

Photo of precursor & carbon membrane

27

CO2 /N2 gas separation measurementCO2 /N2 gas separation measurement

GC

Mass flow meter

Feed gas

He

Oven (Constant temp.) Pressure gauge

Pressurecontrolvalve

Permeate

Retentate

Membrane

Humidifier

Conditions Feed gas: Temperature: 40 °C, CO2 /N2 5 - 80%/ N2 balance, Humidity in feed gas: 0-100RH%Pressure of feed：

0.1 MPa

Pressure of permeate: 0.1 MPa (He sweep)

Feed

28

10-12

10-11

10-10

10-9

10-8

0 50 1000

10

20

30

40

50

0 50 100

Cs2 CO3 (0.71)

10-12

10-11

10-10

10-9

10-8

0 50 100

Cs2 CO3 (4.1)

0

10

20

30

40

50

0 50 10010-12

10-11

10-10

10-9

10-8

0 50 100

Q [m

3 (STP

) m-2

s-1

Pa-1

]

Relative humidity in feed [%]

0

10

20

30

40

50

0 50 100

αC

O2/

N2 [-

]

Relative humidity in feed [%]

Gas separation conditions: Temp.: 40 °C, Feed gas: CO2 /N2 gas mixture (5/95 vol/vol), Feed pressure：

0.1 MPa, Permeate pressure: 0.1 MPa (He sweep method).

(a) QCO2 , QN2 (b) αCO2/N2

Separation performance as a function of relative humidity in feed gas

Cs2 CO3 (0)

• Higher separation performance under the humidified conditions.• Higher separation performance than the original carbon

membranes at high relative humidity.

QCO2

QN2

●, ○:

▼, ▽:

▲, △:

29• RH differently effected on CO2 permeance at Cs(0 %). • CO2 permeance at Cs(4.1%), RH(0) is small. Excess Cs reduced CO2 permeance.

CO2

PermeanceCs2 CO3 content [ % ] in carbon membrane

0 0.71 4.1RH = 0 % 22.5 24.3 1.8 RH = 80 % 5.8 40.5 27.0

• RH only decreased N2 permeance at Cs(0 %). • N2 permeance at Cs(4.1%) is large. Cs enlarges the pore diameter.

N2

PermeanceCs2CO3 content [ % ] in carbon membrane

0 0.71 4.1RH = 0 % 1.0 0.7 1.7

RH = 80 % 0.5 0.9 1.8

Relative permeance in carbon membrane

Relative permeance in carbon membrane

Relative N2 Permeance ( as a basis of N2 permeance at RH = 0 % )

Relative CO2 Permeance ( as a basis of N2 permeance at RH = 0 % )

30

0

10

20

30

40

50

0 50 100

αC

O2/

N2 [-

]

CO2 conc. in feed [%]

10-12

10-11

10-10

10-9

10-8

0 50 100

Cs2CO

3 (0.71)

Cs2CO

3 (1.4)

Cs2CO

3 (4.1)

Q [m

3 (STP

) m-2

s-1

Pa-1

]

CO2 conc. in feed [%]

CO2

N2

Gas separation conditions: Temp.: 40 °C, Humidity in feed gas: 100RH% Feed pressure：

0.1 MPa, Permeate pressure: 0.1 MPa (He sweep method).

Separation performance as a function of CO2 concentration in feed gas

Separation performance as a function of CO2 concentration in feed gas

(a) QCO2 , QN2 (b) α

Constant separation performance at CO2 /N2 =5/95-80/20 %

31

Analysis method for Characterization

Electron probe microanalysis (EPMA)- Cs distribution in the cross-section of carbon free-standing films

Thermogravimetric analysis (TGA) - Thermal decomposition behavior of precursor.

Atomic absorption spectrometry (AAS) - Cs concentration in carbon free-standing films

Inductively coupled plasma mass spectrometry (ICP-MS) - Cs concentration in carbon layer of carbon-coated membranes

X-ray Photoelectron Spectroscopy (XPS) depth profile- Cs distribution in the cross-section of carbon membrane

Nano-Permporometer: -Pore size distribution of carbon-coated membranes by He

32

Distribution of Cs in the cross-section of carbon free-standing films

Distribution of Cs in the cross-section of carbon free-standing films

Cro

ss-s

ectio

nsu

rface

35

10 μm

Intensity

surfa

ce

Carbon free-standing film

Cross-section

EPMA line-mapping

33

(1) Uniform Cs distribution over the cross-section(2) Cs conc. increased as Cs2 CO3 conc. in precursor increased.

Distribution of Cs in the cross-section of carbon free-standing films (EPMA line-mapping)

Distribution of Cs in the cross-section of carbon free-standing films (EPMA line-mapping)

(1) Cs2CO3 (0.71) (2) Cs2CO3 (1.4) (3) Cs2CO3 (4.1)

Cro

ss-s

ectio

nsu

rface

35 60 180

10 μm 10 μm 10 μm

Intensity

surfa

ce

Intensity Intensity

34

0.50.60.70.80.9

11.1

Cs2CO

3 (0.71)

0.50.60.70.80.9

11.1

Cs2CO

3 (0)

0.50.60.70.80.9

11.1

Cs2CO

3 (1.4)

0.50.60.70.80.9

11.1

0 500 1000

Cs2CO

3 (4.1)

Rel

ativ

e w

eigh

t cha

nge

[-]

Temperature [°C]

TGA curve of polyimide precursors with/without Cs2 CO3

TGA curve of polyimide precursors with/without Cs2 CO3

Additional weight loss at 400- 500 °C for Cs2 CO3 -containig precursors

35

Relative permeance in carbon membrane

Relative permeance in carbon membrane

CO2

PermeanceCs2 CO3 content [ % ] in carbon membrane

0 0.71 4.1RH = 0 % 22.5 24.3 1.8 RH = 80 % 5.8 40.5 27.0

N2

PermeanceCs2CO3 content [ % ] in carbon membrane

0 0.71 4.1RH = 0 % 1.0 0.7 1.7 RH = 80 % 0.5 0.9 1.8

Relative N2 Permeance ( as a basis of N2 permeance at RH = 0 % )

Relative CO2 Permeance ( as a basis of N2 permeance at RH = 0 % )

• RH only decreased N2 permeance at Cs(0 %).

• RH differently affected CO2 permeance.

Down

Up

37

Relative permeance in carbon membrane

Relative permeance in carbon membrane

CO2

PermeanceCs2 CO3 content [ % ] in carbon membrane

0 0.71 4.1RH = 0 % 22.5 24.3 1.8 RH = 80 % 5.8 40.5 27.0 Increment -16.7 16.2 25.2

Relative CO2 Permeance ( as a basis of N2 permeance at RH = 0 % )

• There are two pathways of CO2 permeation.1) Dry carbon on surface without H2 O2) Cs + water on surface

• RH differently affected CO2 permeance depending on Cs content.

(a) Decrease value; -16.7 Disappearance of dry carbon(b) Increase value; 25.2 Appearance of Cs + Water(c) Increase value 16.2 Appearance of Cs + water - Disappearance of dry carbon

-16.7 + 25.2 = 8.6

Observed value 16.2 and estimated value 8.6 OK or no?

38

Summary of carbon membrane mechanism

Summary of carbon membrane mechanism

CO2 and N2 permeance is low, because diameters of pores are small.

Low RH

High RH

Surface has CO2 both attractive forces by carbon and Cs +water.

Surface has CO2 attractive force by carbon.

Water on pore surface block out N2 and CO2 .

It is too large attractive force for CO2 to move inside pores.

Pore diameter, both CO2 attractive force by carbon and Cs + water on pore surface effect on CO2 and N2 permeance.

Surface has CO2 attractive force by carbon and Cs +water.

39

PAMAM / Mesoporous silica / Al2 O3 membrane

PAMAM / Mesoporous silica / Al2 O3 membrane

• Conceptual figure of PAMAM / MS / Al2 O3 membrane

Al2 O3

MS : Mesoporous silica crystal + PAMAM

Amorphous silica or crystal defect + PAMAMand

Axes of crystals are random

CO2

CO2

N2 , H2

N2 , H2

Selectivelayer

40

Performances of PAMAM / MS / Al2 O3 MembranePerformancePerformances of PAMAM / MS / Als of PAMAM / MS / Al22 OO3 3 MembraneMembrane

• Separation factor is more than 1000.

• But, CO2 permeance is small.

• Now, studying on structure of selective layer.

10-16

10-15

10-14

10-13

10-12

10-11

10-10

10-9

0.0001

0.001

0.01

0.1

1

10

100

103

104

40 50 60 70 80 90

Perm

eanc

e [m

3 m-2

s-1

Pa-1

]

Sep

arat

ion

Fact

or [-

]

R.H. [%]CO2 / N2 =50% / 50%, Temperature: 313 K

41

Effect of PAMAM on permeanceEffect of PAMAM on permeance

Temp( K )

R.H.(%)

Permeance [m3(STP) sec-1 m2 Pa-1 ]

CO2 /N2

Separation factorCO2 N2

Al2 O3 substrate 298 - 2.5×10-8 2.5×10-8 1.01) Non selective

MS / Al2 O3 298 - 7.6×10-10 8.4×10-10 0.81) Knudsen diffusion

PAMAM / MS / Al2 O3 313 50 2.4×10-12 1.2×10-13 21 CO2 selective

PAMAM / MS / Al2 O3 313 80 3.1×10-12 1.9×10-15 1581

Down

c.a. 1 / 300 c.a. 1 / 7000

Slightly up c.a. 1 / 60

42

Suggestive mechanism of CO2 and N2 separation with PAMAM / MS / Al2 O3

Suggestive mechanism of CO2 and N2 separation with PAMAM / MS / Al2 O3Before humidification After humidification

+

PAMAM H2 O Hydrate PAMAM

CO2 permeate rate decrease1/300

Other gases enormously decrease

1/7000

Surface of mesoporous silica has enough hydrophilic property to adhere hydrate PAMAM at RH = 80 %, so PAMAM can interrupt N2 movement.

N2 CO2

RH = 80 %

Swelling and agglomerated Hydrate PAMAM

43

ConclusionsConclusions

• CO2 attractive force on pore inner-surface and distribution of pore diameter affect membrane performances.

• Carbon membrane needs ten times larger CO2

permeance and twice larger separation factor than those of our result.

• PAMAM / MS / Al2 O3 membrane has very high separation factor, but it needs thousand times larger CO2 permeance.

44

Future WorkFuture Work

• It is possible that PAMAM dendrimer with rigid support and with hydrophilic material, such as mesoporous silica, highly block gases without CO2 .

• It is not precisely unknown how to enhance PAMAM dendrimer CO2 permeation rate.

• We are focusing on the interruptions between PAMAM dendrimer, pore figure and function of pore surface to increase CO2 permeation rate,

temperature effect, and

thickness of selective layer of a membrane.

45

Acknowledgement

SponsorSponsorThe Global Climate and Energy Project at Stanford University

RITE CoRITE Co--ResearchersResearchers Dr. Shingo Kazama, Dr. Katsunori Yogo, Shingo Kazama, Dr. Katsunori Yogo, Dr.TeruhikoDr.Teruhiko Kai, Kai,

Dr. Manabu Miyamoto, Dr. Dr. Manabu Miyamoto, Dr. ShuhongShuhong Duan, Dr. Duan, Dr. KousukeKousuke UoeUoe,,

Dr. Dr. YuzuruYuzuru Sakamoto, Dr. Takayuki Sakamoto, Dr. Takayuki KouketsuKouketsu, Dr. Naoki Yamamoto, Dr. Naoki Yamamoto

Thank you for your attention!