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Movie of CO 2 and H 2 Permeation
QuickTime™ and aSorenson Video 3 decompressor are needed to s ee this picture.
Movie courtesy of Josh Chamot, NSF:http://www.nsf.gov/news/news_summ.jsp?cntn_id=105797&org=NSF
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Membrane Hydrogen Purification: Classic
• H2 /hydrocarbon separation
• H2 /CO ratio adjustment
• NH 3 purge gas recovery
H y d r o t r e a t e r
TreatedOil
H y d r o t r e a t e r
H2
Oil
(1) InertsPurge
(3) FuelGasMembrane
Oil/GasSeparator
(2) Recovered H 2
Photo from Air Liquide
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• Steam reforming of hydrocarbons
accounts for 95% of the hydrogenproduced in the U.S. (DOE 2003):
• U.S. H 2 production was 810 million kg/yr in 2003. (DOE) –
Growth due to:• Low grade crude in refineries• Power source for fuel cells
DOE = http://www.eere.energy.gov/hydrogenandfuelcells/
Fuel Cell Facility (PLUG)
PLUG = http://www.plugpower.com/technology/overview.cfm
• Membranes may be useful for purifying H 2: - Low capital costs- Compact size- Ease of operation
Interest in Hydrogen
CH 4 2 H
2O CO
2 4 H 2
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Fuel Cell OperationFrom Jim McGrath, Virginia Tech
Source: H Power
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Just what the environmentneeds from a car. Water .
Hydrogen powered Fuel
Cell vehiclesonly emitwater.
From Jim McGrath, Virginia Tech
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Cost Estimates for H 2 Production
http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/vision_doc.pdf
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FutureGen
"Today I am pleased to announce that the UnitedStates will sponsor a $1 billion, 10-yeardemonstration project to create the world's first
coal-based, zero-emissions electricity andhydrogen power plant..."President George W. Bush
February 27, 2003
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FutureGen Concept
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• High flux (high permeability, thin)• High selectivity
• Tolerance to all feed components• Mechanical stability• Ability to be packaged in high surface area modules• Excellent manufacturing reproducibility, low cost
Ideal Membrane Characteristics
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16D. Wang, et al., ACS Symp. Ser., v. 744, p. 107, 1999.
~5,000 m 2 /m 3
Contaminated Natural Gas(High Pressure) CO 2- rich permeate(Low pressure)
Upgraded Natural gas(High Pressure)
Hollow Fiber Module
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Component Specification
CO 2 <2%
H2O <120 ppm
H2S <4 ppm
C 3+ hydrocarbons 950-1050Btu/ft 3(STP)
Dew Point -20C
Inerts (N 2, CO 2, He, etc.) <4%
Amine Scrubber
Membrane Unit
U.S. Pipeline Specifications 1:
Potential membrane applications:• Acid gas removal• N2 removal• Higher hydrocarbon removal• Dehydration1R.W. Baker, I.&E.C. Res., 41, 1393 (2002).
Natural Gas Purification
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18J. Membr. Sci., 107, 1-21 (1995)
Gas Transport in Polymers:Solution-Diffusion Model
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10 -13
10 -12
10 -11
10 -10
10 -9
10 -8
10 -7
10 -6
50 100 150 200 250 300 P e r m e a
b i l i t y [ c m
3 ( S T P )
c m
/ ( c
m 2
s c m
H g
) ]
Vc [cm 3 /mole]
PDMS, 35°C
PSF, 23°C
H2
O 2N2
CO 2
CH 4
C 2H6C 3H8
H2
He
O 2
NH 3
N2
CH4
CO 2
SF 6
CCl2F
2 C 2Cl 2F4
PDMS: n
Si O
CH 3
CH3
SO2
O C
CH3
CH3
O
n
PSF:
Characteristic Polymer Permeation Properties
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10 -12
10 -11
10 -10
10 -9
10 -8
10 -7
10 -6
10 -5
10 -4
10 100 1000
D i f f u s
i o n
C o e
f f i c
i e n
t [ c m
2 / s ]
Vc [cm 3 /mole]
PDMS
PSF
H2O 2
N2
CO 2
CH 4
CF 4
C 2H6C 3H8
C 2F 6 C 3F8
He
O 2
N2
CO 2
CH 4
C 4H10
10 -4
10 -3
10 -2
10 -1
100
0 100 200 300 400 500
S o l u b i l i t y [ c m
3 ( S T P ) / ( c m
3
c m
H g
) ]
T c [K]
PSF
PDMS
H2 N2 O 2CH 4 CO 2 C3 H8n-C 4 H10
C2
H6
B.D. Freeman and I. Pinnau, "Polymeric Materials for Gas Separations," in Polymeric Membranes forGas and Vapor Separations: Chemistry and Materials Science, Edited by B.D. Freeman and I. Pinnau,ACS Symp. Ser. 733, pp. 1-27 (1999).
Solubility and Diffusivity Characteristics
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• Traditional membrane materials• Glassy polymers• Designed to be strongly size-sieving
• Low permeability
• High selectivity due to high diffusion selectivity
• Upon plasticization, selectivity decreases, sometimes strongly• H2 selective in H 2 /CO 2 separations
• Our approach• Rubbery polymers
• Designed to be strongly solubility-selective• High permeability• Selectivity derives primarily from high solubility selectivity
• Upon plasticization, separation properties can increase insome cases (CO 2 /H 2)
Materials Design Approach P
A S
A D
A A / B
S A
S B
D A
D B
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O
H3C C N
THF
ACN
Effect of Polar Groups in Liquid Solvents onCO 2 Solubility and CO 2 /N 2 Solubility Selectivity
Lin and Freeman, J. Molecular Structure , 739(1-3), 57-74 (2005).
1
10
100
1
10
100
10 15 20 25 30 35 C O
2 S o
l u b i l i t y [ c m
3 ( S
T P ) / ( c m
3 a
t m ) ]
C O
2 / N
2 S o
l u b i l i t y S e
l e c
t i v i t yTHF
AN
ACN
DMFC6 MeOHDMS
MAc
TCM
PC
Solvent Solubility Parameter [MPa 0.5 ]
THF ACN
25 o C
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R =CH 3; poly(ethylene glycol) methylether acrylate (PEGMEA); n=8
R =H; poly(ethylene glycol) acrylate(PEGA); n=7
Poly(ethylene oxide) diacrylate (PEGDA: Crosslinker)
UV
n
14] [ O CH 2 CH 2 O
O
C CH CH 2 C
O
CH CH 2
C
C
O O
C C
C C
C C
PEO O
PEO
C
C O
PEO
OR
C
C
PEO
OR
O
O
C
O
C PEO
O
O O
O
C C C C C C
CH 2 CH C O
O CH 2 CH 2 OR [ ]
Crosslinked Poly(ethylene oxide) [XLPEGDA]
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Mixed Gas Separation
10 -1
10 0
10 1
102
10 -2 10 -1 10 0 10 1 10 2 10 3 10 4
C O
2 / H
2
CO2 Permeability [Barrer]
Upper Bound35 oC
10 oC
-20 oC
Lin, Haiqing, E. van Wagner, B.D. Freeman, L.G. Toy, and R.P. Gupta, “Plasticization -Enhanced H 2 Purification Using Polymeric Membranes,” Science, 311(5761) , 639-642 (2006).
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Mixed Gas CO 2 /CH 4 Separation
PEGDA (crosslinker; 30wt %)
CH 2 CH C
O
O CH 2 CH 2 OCH 3[ ]8
PEGMEA (monomer: 70 wt%)
]13[ O CH 2 CH 2 O
O
C CH CH 2 C
O
CH CH 2
0
10
20
30
40
50
0 5 10 15 20
C O
2 / C H
4
CO 2 Partial Pressure [atm]
35 oC
PEGDA/PEGMEA-30
mixed
6FDA- m PD
Pure
10 0
101
10 2
10 0 10 1 10 2 10 3 10 4 10 5
CO 2 Permeability [Barrer]
C O
2 / C H
4
CA
-20 oC
10 oC
35 oC
upper bound
Lin, Haiqing, E. van Wagner, B.D. Freeman, and I. Roman, “High Performance PolymerMembranes for Natural Gas Sweetening,” Advanced Materials, 18 , 39-44 (2006).
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THANK YOU!
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