Movie of CO2 and H2 Permeation

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Movie of CO2 and H2 Permeation
Movie courtesy of Josh Chamot, NSF http//www.nsf
.gov/news/news_summ.jsp?cntn_id105797orgNSF
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Membrane Hydrogen Purification Classic

• H2/hydrocarbon separation
• H2/CO ratio adjustment
• NH3 purge gas recovery

Photo from Air Liquide
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Interest in Hydrogen

• U.S. H2 production was 810 million kg/yr in 2003.
  (DOE)
• Growth due to
• Low grade crude in refineries
• Power source for fuel cells

• Steam reforming of hydrocarbons accounts for 95
  of the hydrogen produced in the U.S. (DOE 2003)

Fuel Cell Facility (PLUG)

• Membranes may be useful for purifying H2
• - Low capital costs
• - Compact size
• - Ease of operation

DOE http//www.eere.energy.gov/hydrogenandfuelce
lls/
PLUG http//www.plugpower.com/technology/overvie
w.cfm
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Air Liquide Slides courtesy of Dr. Greg Fleming,
UT Ph.D. 87
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(No Transcript)
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Air Products Slide courtesy of Dr. Lloyd Robeson
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(No Transcript)
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Fuel Cell OperationFrom Jim McGrath, Virginia
Tech
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Just what the environment needs from a car.
Water.
Hydrogen powered Fuel Cell vehicles only emit
water.
From Jim McGrath, Virginia Tech
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H2 Purity Requirements for Fuel Cells
A National Vision of Americas Transition to a
Hydrogen Economy - 2030 and Beyond, U.S. DOE,
2/2002.
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Cost Estimates for H2 Production
http//www.eere.energy.gov/hydrogenandfuelcells/pd
fs/vision_doc.pdf
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FutureGen

• "Today I am pleased to announce that the United
  States will sponsor a 1 billion, 10-year
  demonstration project to create the world's first
  coal-based, zero-emissions electricity and
  hydrogen power plant..."
• President George
  W. Bush
• February 27, 2003

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FutureGen Concept
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Gas Separations Using Membranes

• Current applications
• Air separation - mainly N2 enriched air
• Natural gas treatment - acid gas removal
• H2 separation - H2 from hydrocarbons, ammonia
  purge, syngas
• Removal of vapors from mixtures with light gases
  (vapor separation)
• Advantages
• Low energy separation (no phase change)
• Reliable (no moving parts)
• Small footprint
• Drawbacks
• Incomplete separation (need higher selectivity)
• Low chemical/thermal stability (need more
  resistant matls.)

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Ideal Membrane Characteristics

• 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

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Hollow Fiber Module
Contaminated Natural Gas (High Pressure)
CO2- rich permeate (Low pressure)
5,000 m2/m3
Upgraded Natural gas (High Pressure)
D. Wang, et al., ACS Symp. Ser., v. 744, p. 107,
1999.
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Natural Gas Purification
U.S. Pipeline Specifications1
Amine Scrubber

• Potential membrane applications
• Acid gas removal
• N2 removal
• Higher hydrocarbon removal
• Dehydration

Membrane Unit
1R.W. Baker, I.E.C. Res., 41, 1393 (2002).
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Gas Transport in Polymers Solution-Diffusion
Model
J. Membr. Sci., 107, 1-21 (1995)
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Characteristic Polymer Permeation Properties
PDMS
PSF
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Solubility and Diffusivity Characteristics
B.D. Freeman and I. Pinnau, "Polymeric Materials
for Gas Separations," in Polymeric Membranes for
Gas and Vapor Separations Chemistry and
Materials Science, Edited by B.D. Freeman and I.
Pinnau, ACS Symp. Ser. 733, pp. 1-27 (1999).
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Materials Design Approach

• 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 H2/CO2 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 in some cases (CO2/H2)

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Effect of Polar Groups in Liquid Solvents on CO2
Solubility and CO2/N2 Solubility Selectivity
THF
ACN
Lin and Freeman, J. Molecular Structure,
739(1-3), 57-74 (2005).
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Crosslinked Poly(ethylene oxide) XLPEGDA




CH
CH
O
C
CH
CH
O
C
CH
CH
2
2
2
2
14
O
O
Poly(ethylene oxide) diacrylate (PEGDA
Crosslinker)
n
UV
RCH3 poly(ethylene glycol) methyl
ether acrylate (PEGMEA) n8 RH
poly(ethylene glycol) acrylate (PEGA)
n7
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Mixed Gas Separation
Lin, Haiqing, E. van Wagner, B.D. Freeman, L.G.
Toy, and R.P. Gupta, Plasticization-Enhanced H2
Purification Using Polymeric Membranes, Science,
311(5761), 639-642 (2006).
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Mixed Gas CO2/CH4 Separation
PEGDA (crosslinker 30wt )
PEGMEA (monomer 70 wt)
Lin, Haiqing, E. van Wagner, B.D. Freeman, and I.
Roman, High Performance Polymer Membranes for
Natural Gas Sweetening, Advanced Materials, 18,
39-44 (2006).
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THANK YOU!