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Movie of CO 2 and H 2 Permeation

Explore the current applications, advantages, and challenges of using membranes for purifying hydrogen, including ideal membrane characteristics. Learn about the potential of hollow fiber modules and polymer permeation properties in gas separation.

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Movie of CO 2 and H 2 Permeation

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  1. Movie of CO2 and H2 Permeation Movie courtesy of Josh Chamot, NSF: http://www.nsf.gov/news/news_summ.jsp?cntn_id=105797&org=NSF

  2. Membrane Hydrogen Purification: Classic • H2/hydrocarbon separation • H2/CO ratio adjustment • NH3 purge gas recovery Photo from Air Liquide

  3. 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/hydrogenandfuelcells/ PLUG = http://www.plugpower.com/technology/overview.cfm

  4. Air Liquide Slides courtesy of Dr. Greg Fleming, UT Ph.D. ‘87

  5. Air Products Slide courtesy of Dr. Lloyd Robeson

  6. Fuel Cell OperationFrom Jim McGrath, Virginia Tech Source: H Power

  7. Just what the environment needs from a car. Water. Hydrogen powered Fuel Cell vehicles only emit water. From Jim McGrath, Virginia Tech

  8. H2 Purity Requirements for Fuel Cells A National Vision of America’s Transition to a Hydrogen Economy - 2030 and Beyond, U.S. DOE, 2/2002.

  9. Cost Estimates for H2 Production http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/vision_doc.pdf

  10. 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

  11. FutureGen Concept

  12. 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.)

  13. 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

  14. 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.

  15. 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).

  16. Gas Transport in Polymers: Solution-Diffusion Model J. Membr. Sci., 107, 1-21 (1995)

  17. Characteristic Polymer Permeation Properties PDMS: PSF:

  18. 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).

  19. 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)

  20. 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).

  21. Crosslinked Poly(ethylene oxide) [XLPEGDA] OR PEO O C C C C C C C C O [ ] O C CH C O CH CH CH OR O O 2 2 C 2 C PEO O PEO O PEO O OR PEO O O C O C O C C C C C C C [ ] CH CH C O CH CH O C CH CH 2 2 2 2 14 O O Poly(ethylene oxide) diacrylate (PEGDA: Crosslinker) n UV R=CH3; poly(ethylene glycol) methyl ether acrylate (PEGMEA); n=8 R=H; poly(ethylene glycol) acrylate (PEGA); n=7

  22. 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).

  23. Mixed Gas CO2/CH4 Separation [ ]13 CH CH C O CH CH CH CH O C 2 2 2 2 O O [ ]8 CH C O CH CH CH OCH3 2 2 2 O 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).

  24. THANK YOU!

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