Hydrogen Production With Advanced Protonic Conductors

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Hydrogen Production With Advanced Protonic
Conductors
NASA Report, November 2004

• E. D. WachsmanMaterials Science and
  EngineeringUniversity of Floridaewach_at_mse.ufl.ed
  u

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Outline

• Introduction
• Fundamentals and Materials Development
• Membrane Reactor Fabrication
• Recent Accomplishments

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DOEs Future Gen

• Hydrogen and electricity co-generation from coal
• Zero emissions and CO2 capture

Hydrogen Production from Fossil Fuels with
Proton and Oxygen-Ion Transport Membranes, E. D.
Wachsman and M. C. Williams, Interface, Volume
13, No.3, Fall 2004
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H2 PRODUCTION FROM HYDROCARBON FUEL WITH PROTON
CONDUCTING MIEC

• H2 permeates through membrane
• No further separation required
• No total oxidation products formed

Hydrogen Production from Fossil Fuels with
Proton and Oxygen-Ion Transport Membranes, E. D.
Wachsman and M. C. Williams, Interface, Volume
13, No.3, Fall 2004
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Catalytic Membrane Fuel Processing Unit - CMFPU

• Conceptual design of an autothermal catalytic
  membrane fuel processing unit for conversion of
  hydrocarbon fuels to pure H2 showing functions
  of O2 and H2 transport membranes
• Combines exothermic Oxidation with endothermic
  Steam Reforming

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Autothermal Temperature as a Function of Heat
Transfer Efficiency

• Is the heat of reaction sufficient to bring the
  CMFPU reactor to the required H2 membrane
  temperature? -gt Yes !!
• O2/H2O 0.3 Tgt 1000C

CH4 0.375 O2 1.25 H2O CO2 3.25 H2
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Cost of Hydrogen Production
CH4 0.375 O2 1.25 H2O CO2 3.25 H2

• 3.25 H2/CH4
• CH4 0.20C/m3
• 0.15/m3 H2
• 0.015 /liter H2

Assumes 100 conversion and selectivity, air
and water are free, and ignores capital cost
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Outline

• Introduction
• Fundamentals and Materials Development
• Membrane Reactor Fabrication
• Recent Accomplishments

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ADDING ELECTRONIC CONDUCTIVITY TO A PROTON
CONDUCTOR

• Two phase membrane
• Ion conducting phase (BaCeO3, SrCeO3)
• Electron conducting phase (Pd)
• Single phase membrane
• Add multivalent M3/2 cation
• BaCe1-xMxO3-d, SrCe1-xMxO3-d

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H2 FLUX RELATIONSHIP

• Flux across an oxide membrane calculated using
  Wagner equation
• Assumes that bulk diffusion is rate limiting step
• ?t is the total conductivity
• ?i zi q ui i, (i OHO, VO, e)
• Transference number, ti ?i / ?t
• F is Faradays constant
• Requires integration of both O2 and H2 potential
  gradients
• 1/Membrane thickness (L)

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Effect of Membrane Thickness

• At high temperature (gt750C) permeation is bulk
  transport controlled
• Flux is linear with 1/L
• At lower temperature permeation is surface
  kinetic controlled

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Effect of Surface Modification

• Modification of the surface with simple Pt paste
  (solid lines) significantly increases flux (2X)

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FUNDAMENTALS Summary

• High temperature protonic conductors offer
  tremendous potential for H2 production
• Adding electronic conductivity significantly
  increases H2 flux
• Two phase Pd-BCGO
• Single phase multivalent Eu3/2
• 0.5 cc/cm2 min H2 flux through 2 mm thick
  membrane
• Complex defect equilibria
• Flux modeling requires O2/H2O/H2 activities
• Mixed bulk/surface control?
• UF Proprietary material has potential for even
  better H2 flux at Water Gas Shift temperature
  range

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Outline

• Introduction
• Fundamentals and Materials Development
• Membrane Reactor Fabrication
• Recent Accomplishments

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H2 Membrane Fabrication
Conventional tape casting of Ni-GDC support tube
material
NiO-GDC green tape
Partially sinter then coat with membrane
Roll tape to form tube
Eu- doped SrCeO3-d layer
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Closed End NiO-GDC Tube Before and After
Pre-sintering
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H2 Membrane Fabrication
Eu-doped SrCeO3-d
NiO-GDC
1400oC 5 hrs co-fired Eu-doped SrCeO3-d / NiO-GDC
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Microstructures of Eu-doped SrCeO3 on NiO-GDC
support
Before hydrogen treatment
After hydrogen treatment
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Outline

• Introduction
• Fundamentals and Materials Development
• Membrane Reactor Fabrication
• Recent Accomplishments

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Chemical Reactivity Between SrCe0.95Eu0.05O3-d
and Support Tube Materials
GDC
GDC Ce0.8Gd0.2O2-d
GDC
SC SrCe0.9Eu0.1O3-d
GDC
No Reaction
SC
GDC
Intensity (a.u)
GDC
SC
SC
GDC SC
GDC SC
SC
SC
GDC
SC
SC
NiO- Eu-doped SrCeO3
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Gadolium doped Cerium oxide Thermal expansion of
NiO-GDC and SrCe0.90Eu0.10O3-d
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Yttrium stabilized zirconium oxide (YSZ) Thermal
expansion of NiO-YSZ and SrCe0.90Eu0.10O3-d
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10 mol Eu-doped SrCeO 3-d Thermal expansion of
NiO-SrCeO3 and SrCe0.90Eu0.10O3-d
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Hydrogen Membrane Cell Fabrication Shrinkage
behavior according to the firing temperature
Pre-sintering region
Final sintering region
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Hydrogen Membrane Cell Fabrication Conventional
dip-coating method
After dried
After coated
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Coating equipment for Hydrogen membrane thin
film To prevent pin-holes
Rubber for partially sintered support tube
Partially sintered NiO-SrCeO3 porous support tube
10mol Eu-doped SrCeO 3-d coated layer
Glass chamber
Vacuum pump (to decrease the air pressure in the
glass chamber)
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Hydrogen Membrane Cell Fabrication Modified
dip-coating method
Solvent
Eu-doped SrCeO3 powder
Coated layer
Porous support tube
Coated layer
Porous support tube
After dried
After coated
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Hydrogen Membrane Cell Fabrication
Microstructures for Eu-doped SrCeO3 films on
NiO-SrCeO3 support tube
Before hydrogen treatment
1425oC 5hrs
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Hydrogen Membrane Cell Fabrication Eu-doped
SrCeO3-d via Citrate Process
Before hydrogen treatment
After hydrogen treatment
Pre-sintering cond. 1150oC/4 hrs, Final
sintering cond. 1425oC/5 hrs
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Successfully Achieved MAJOR Milestone
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NEXT PHASEHydrogen Membrane Reactor Fabrication
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FUTURECatalytic Membrane Fuel Processing Unit

• Conceptual design of an autothermal catalytic
  membrane fuel processing unit for conversion of
  hydrocarbon fuels to pure H2 showing functions
  of O2 and H2 transport membranes
• Combines exothermic Oxidation with endothermic
  Steam Reforming

Also, DOE Proposal with Praxair
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ACKNOWLEDGMENTS

• Group
• Dr. Xin Guo (Group Leader)
• Dr. H. Yoon (Porous tube fabrication)
• J. Rhodes (PhD student, single phase BaCeO3)
• G. Zhang (PhD student, UF Proprietary compound)
• T.K. Oh (PhD student, SrCeO3 composition
  optimization)
• J. Li (PhD student, catalyst incorporation)
• S.J. Song (PhD May 2003, SrCeO3 Cahn
  Microbalance)
• R. Bagul (MS August 2004, colloidal deposition)
• B. Krishnamurthi (MS May 2000, two phase
  Pd-BaCeO3)
• Support
• NASA
• Consortia for Conversion of Natural Gas (CANMET)
• US DOE (Argonne National Lab)