Project ID: PD24 5-25-2005 1

High Temperature Solid OxideElectrolyzer System

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Steve Herring Jim O’Brien, Paul Lessing, Will Windes, Dan Wendt,Carl Stoots, Grant Hawkes, Mike Mc Kellar, Manohar SohalIdaho National Laboratory

Joseph J. Hartvigsen, S. Elangovan, Dennis LarsenCeramatec, Inc.

Mark Petri, Richard Doctor, Bilge Yildiz, Diana Matonis, Tanju Sofu, Debbie MyersArgonne National Laboratory

Brian BischoffOak Ridge National Laboratory

2005 DOE Hydrogen, Fuel Cells & Infrastructure Technologies Program Review

Project ID: PD24 5-25-2005 2

OverviewBudget

(total for INL plus partners below)

FY-04: $1050 k FY-05: $1440 k

Partners

Ceramatec, Inc.Development of planar cell technology

Argonne National LaboratoryComputation Fluid Dynamics of CellsOverall Plant FlowsheetAdvanced Electrode and Electrolyte Materials

Oak Ridge National LaboratoryHigh Temperature Inorganic Membranes for Steam/Hydrogen separations

Project ID: PD24 5-25-2005 3

Technical BarriersAdapted from 3.1.4.2.2 Hydrogen Generation by {Water} ElectrolysisG. Capital Cost - R&D is needed to develop lower cost materials with improved manufacturing capability to lower capital costs while improving the efficiency and durability of the system. Development of larger systems is also needed to improve economies of scale.

H. System Efficiency – Development is needed for low-cost cell stack optimization considering efficiency, electrochemical compression and durability.

I. Grid Electricity Emissions – Low-cost, carbon-free electricity sources are needed.K. Electricity Costs – High Temperature solid oxide electrolysis can use lower cost energy in the form of steam for water splitting to decrease electricity consumption. Technically viable systems for low-cost manufacturing need to be developed for this technology.

Project ID: PD24 5-25-2005 4

Research Objectives

• Develop energy-efficient, high-temperature, solid-oxide electrolysis cells (SOECs) for hydrogen production from steam

• Develop and test integrated SOEC stacks operating in the electrolysis mode

• Develop optimized plant configuration for coupling to Generation IV Reactor

• Combine components in an Integrated Laboratory-scale Experiment

• Scale-up to a 200 kW Pilot Plant and a 1 MW Engineering Demonstration Facility

Project ID: PD24 5-25-2005 5

Approach (vs Objectives)• Develop energy-efficient, high-temperature, solid-oxide

electrolysis cells (SOECs) for hydrogen production from steam.– Optimize energy efficiency, cost and durability

optimize electrolyte materials (e.g., YSZ, ScSZ, sealants)investigate alternate cell configurations (e.g., electrode-supported or tubular)

• Develop and test integrated SOEC stacks operating in the electrolysis mode with an aim toward scale-up to a 200 kW Pilot Plant and a 1 MW Engineering Demonstration Facility– Increase SOEC stack durability and sealing with regard to thermal

cycles– Improve material durability in a hydrogen/oxygen/steam environment– Perform a progression of electrolysis stack testing activities at

increasing scales and complexities – Develop computational fluid dynamics (CFD) capability for SOEC– Utilize advanced systems modeling codes (e.g. HYSYS, ASPEN)– Perform Cost and Safety Analyses

Project ID: PD24 5-25-2005 6

HTE FY-05 Task Area OverviewHTE Systems Definition FY 05 k$ Description/GoalWP# Org/ PIs (inc. FY04 Carryover)[ID15EL11] INL / O’Brien, Herring 400 Engineering analyses in support

of experiments anddevelopment of larger scale HTE facilities.

[CH15EL11] ANL / Petri 237 ANL work also includes SOEC materials research

HTE Experiments[ID15EL21] INL / Stoots, Herring 832 HTE Experimental activities,

including scale-up.HTE Membrane Technologies[OR15EL21] ORNL / Bischoff 60 Evaluate the applicability

of inorganic high-temperature membranes for use in large scale HTE operations

Project ID: PD24 5-25-2005 7

Technical AccomplishmentsHTE Accomplishments since May 2004

FY2004 • An assessment of the engineering materials issues and requirements for construction of an HTE system was completed to provide input to the high temperature materials testing program. • The high-temperature electrolysis system configuration study was completed, identifying the options and technical issues for HTE systems, including electrolyzer cell and module configurations and high-temperature steam distribution.• An experiment plan for the development of high-temperature electrolysis components and systems was completed to provide input to the longer term scaling of HTE systems. • An assessment of the high temperature reactor and HTE process interface requirements was completed• Completed engineering analyses for high-temperature electrolysis scaling demonstration experiments, including steam distribution systems and electrolyzer cell and module configurations.• Completed a series of button cell experiments to examine cell operational characteristics under a range of conditions. • Completed initial testing of a 10 cell stack in preparation for hydrogen production testing. • Complete final design for laboratory-scale HTE experiments

FY2005(to date)

• Developed engineering process model for HTE system performance evaluation, including the development of CFD and electrochemical modeling for planar geometry electrolyzer cells, including mass and thermal transport. • Demonstrated high-temperature electrolysis stack testing at a production rate of 50 normal liters per hour of hydrogen. • Produced 15 button cells using plasma deposition on nickel aluminide substrate (now being tested)

Project ID: PD24 5-25-2005 8

Theoretical Efficiency of High Temperature Electrolysis

35%

40%

45%

50%

55%

500 600 700 800 900Reactor Outlet Temperature (C)

Effic

ienc

y

Electrical generation eff.Hydrogen production eff.

P=1 atm

0

2

4

6

8

10

12

14

16

0

0.5

1

1.5

2

2.5

3

3.5

0 200 400 600 800 1000

Ener

gy D

eman

d pe

r uni

t mas

s of s

team

kWh/m3H2

T (C)

liquid steam

ΔHR, Total Energy Demand

ΔGR, Electrical Energy Demand

TΔSR, Heat Demand

MJ/kg H2O

Energy Input to Electrolyser

Project ID: PD24 5-25-2005 9

Schematic of Stack Testing Apparatus

N2

H2 + Ar + H2O

Air + O2

H2

Air

H2O + Ar + H2

P

TTdp

Tdp

TA

V+-Humidifier

Furnace

3-way valve

Humidifier bypass

Stack

T

T

T

T

CoolingWater

Condenser

H2 Exhaust

PowerSupply

Project ID: PD24 5-25-2005 10

Electrolysis Stack Performance Testing Hardware

10-cell electrolysis stack; has produced up to 100 SLPH H2

Stack mounted on test fixture

View of air flow passages, inside furnace at 800°C

Project ID: PD24 5-25-2005 11

Hydrogen Production at 830° C

0

200

400

600

800

1000

1200

0 2 4 6 8 10 12 14 16

Hyd

roge

n Pr

oduc

tion

Rat

e, sc

cm

current, I, Amps

based on dewpoint measurements

based on stack ionic current

Test conditions:N2: 2000 sccmH2: 400 sccmH2O inlet dewpoint: 80 CT

furnace: 830 C

Hydrogen production rate, N

L/hr

72

60

48

36

24

12

0

Project ID: PD24 5-25-2005 12

operating voltage, V

current density, A/cm2he

atflu

x,W

/cm

2

-1.4-1.2-1-0.8-0.6-0.4

-0.3-0.2-0.100.10.20.30.4

-0.2

0

0.2

0.4

reactionohmicnet

thermal neutralvoltage

open-cellpotential

electrolysisfuel cell

Energy Budgets in fuel-cell and electrolysis modes

Stack ASR = 1.25, T = 927 C, yH2,i = 0.1, yH2,o = 0.95

FhV Rtn 2

Δ−=

(1.291 V at 1200 K)

Project ID: PD24 5-25-2005 13

Overall hydrogen production efficiencies as a function of power-production thermal efficiency and electrolyzer per-cell operating voltage

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6

0.65

0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5

ηT

Vop

0.30

0.35

0.40

0.45

ηP = 0.50

Eo

Te = 800 C

Vtn

Project ID: PD24 5-25-2005 14

Stack temperatures during a DC potential sweep; comparison to FLUENT results

790

792

794

796

798

800

802

804

8 9 10 11 12 13 14

T (C)

Stack operating voltage (V)

stack internal 1

stack internal 4stack internal 3

stack internal 2 air inlet

furnace

Tf (C)T

dp, i (C)sccm H2sccm N2sweep #

80082.941120184

FLUENT

Project ID: PD24 5-25-2005 15

FLUENT Single-Cell SOEC Model

Project ID: PD24 5-25-2005 16

CFD Contour Plots

H2/H2O

Air

Project ID: PD24 5-25-2005 17

near thermal minimum near thermal neutral above thermal neutral

0.156 A/cm2; 1.164 V1100

1104.5

1105.5

Electrolyte/insulator temperature contours0.2344 A/cm2; 1.306 V 0.4688 A/cm2; 1.640 V

1091

1197

1139

Electrolyte current density contours

-1404

-1878

-2097

-2734

-3892

-5158

Project ID: PD24 5-25-2005 18

0.8

0.9

1

1.1

1.2

1.3

0.00 0.05 0.10 0.15 0.20 0.25

FLUENTExperimental

Per-

Cel

l Ope

ratin

g V

olta

ge (V

)

Current Density (A/cm2)

Voltage-current characteristics of actual electrolysis stack and FLUENT model

Electrode exchange current densities and several gap electrical contact resistances were determined empirically by comparing

FLUENT predictions with stack performance data

Project ID: PD24 5-25-2005 19

HTE System DefinitionANL, PIs: Petri, Myers, Carter, Yildiz

Temperature (oC)Oxygen Electrode Composition 800 850 900 1000

La0.8Sr0.2MnO3 (LSM) 8.4 nd 3.7 0.65

La0.8Sr0.2FeO3 (LSF-s) 2.2 1.2 0.58 nd

LaNiO3 (LN) 1.4 0.89 0.37 0.082

La0.8Sr0.2CoO3 (LSC) 1.3 0.67 0.27 0.080

La0.7Sr0.2FeO3 (LSF-ns) 0.81 0.38 0.19 0.054

10

0.01

0.1

1

700 750 800 850 900 950 1000 1050Temperature (°C)

ASR

(Ω-c

m2 )

LSF-ns

LSMLSF-s

LN

LSC

• ANL’s non-stoichiometric LSF (LSF-ns) shows improved oxygen electrode performance over LSM.• Further improvement in LSF-ns performance is expected by optimizing the electrode microstructure and

electrode/electrolyte interface.• Single-phase, mixed-conducting hydrogen electrodes are being studied as alternatives to Ni-YSZ (Nickel – Yttria

Stabilized Zirconia). • Addresses oxidation-related degradation in high steam environment.

-s : stoichiometric-ns: non-stoichiometricnd : no data

Area-specific resistance (ASR), Ω-cm2

ANL’s oxygen and hydrogen electrode development

Project ID: PD24 5-25-2005 20

TimelineProject start: Jan ‘03 (DOE-EE)

(became part of the Nuclear Hydrogen Initiative Jan ’04)

HTE Systems Analysis and Experiments

FY2005 •Develop engineering process model for HTE system performance evaluation, including the development of CFD and electrochemical modeling for planar geometry electrolyzer cells, including mass and thermal transport. Done•Demonstrate high-temperature electrolysis stack testing at a production rate of 50 normal liters per hour of hydrogen. . Done•Demonstrate high-temperature electrolysis stack testing at a production rate of 100 normal liters per hour of hydrogen. •Complete conceptual design documentation for HTE pilot-scale experiments

FY2006 •Complete design of HTE integrated laboratory-scale experiments•Construct stack /module arrays for integrated laboratory-scale experiments

FY2007 •Begin HTE integrated lab-scale experimental operations•Complete HTE cell testing •Conduct HTE stack / module tests•Perform initial testing on candidate pilot scale module tests •Complete preliminary pilot scale experiment design

FY2008 •Pilot-scale experiment final design•Complete HTE integrated lab-scale experimental operations •Implement cell/module technology improvements

Project ID: PD24 5-25-2005 21

Supplemental Slides

The following three slides are for the purposes of the reviewers only – they are not to be presented as part of your oral or poster presentation. They will be included in the hardcopies of your presentation that might be made for review purposes.

Project ID: PD24 5-25-2005 22

INL HTE Publications since May 2004:

Hawkes, G. L., O’Brien, J. E., Stoots, C. M., Herring, J. S., Shahnam, M., “Thermal and Electrochemical Three Dimensional CFD Model of a Planar Solid Oxide Electrolysis Cell,” to be presented at the 2005 ASME Heat Transfer Conference, July 17-22, 2005, San Francisco.

O’Brien, J. E., Stoots, C. M., Herring, J. S., Lessing, P. A., Hartvigsen, J. J., and Elangovan, S., “Performance Measurements of Solid-Oxide Electrolysis Cells for Hydrogen Production from Nuclear Energy,” Journal of Fuel Cell Science and Technology, Vol. XX, August 2005, pp. XXX-XXX.

Herring, J. S., O’Brien, J. E., Stoots, C. M., and Hawkes, G. L., “Progress in High-Temperature Electrolysis for Hydrogen Production using Planar SOFC Technology,” submitted for presentation at the 2005 AIChE Spring Annual Meeting, April 10 –14, 2005, Atlanta, GA.

O’Brien, J. E., Stoots, C. M., Herring, J. S., and Hartvigsen, J. J.,“Hydrogen Production Performance of a 10-Cell Planar Solid-Oxide Electrolysis Stack,” submitted for presentation at the ASME 3rd International Conference on Fuel Cell Science, Engineering, and Technology, May 23 – 25, 2005, Ypsilanti, MI.

Hawkes, G. L., O’Brien, J. E., Stoots, C. M., Herring, J. S., Shahnam, M., “CFD Model of a Planar Solid Oxide Electrolysis Cell for Hydrogen Production from Nuclear Energy,” to be presented at the 11th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics NURETH-11, Popes Palace Conference Center, Avignon, France, October 2-6, 2005.

O’Brien, J. E., Herring, J. S., Stoots, C. M., Lessing, P. A., “High-Temperature Electrolysis for Hydrogen Production From Nuclear Energy,” to be presented at the 11th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics NURETH-11, Popes Palace Conference Center, Avignon, France, October 2-6, 2005.

Herring, J. S., O’Brien, J. E., Stoots, C. M., Lessing, P. A., Hartvigsen, J. J., and Elangovan, S., “Hydrogen Production through High-Temperature Electrolysis,” chapter in book edited by Dr. Masao Hori, "Nuclear Production of Hydrogen - Technologies and Perspectives for Global Deployment, International Nuclear Societies Council, Current Issues in Nuclear Energy, 2004.

Herring, J. S., Anderson, R., Lessing, P. A., James E. O’Brien, J. E., Stoots, C. M., Hartvigsen, J. J., and Elangovan, S.,“Hydrogen Production through High-Temperature Electrolysis in a Solid Oxide Cell,” presented at the National Hydrogen Association 15th Annual Conference, Los Angeles, April 26-29, 2004.

O’Brien, J. E., Stoots, C. M., Herring, J. S., and Lessing, P. A., “Characterization of Solid-Oxide Electrolysis Cells for Hydrogen Production via High-Temperature Steam Electrolysis,” Proceedings, 2nd International Conference on Fuel Cell Science,Engineering, and Technology, June 14-16, 2004, Rochester, NY, paper# 2474, pp., 219 – 228.

S. Elangovan, J. Hartvigsen, J. E. O’Brien, C. M. Stoots, J. S. Herring, P. A. Lessing, “Operation and Analysis of SOFCs in Steam Electrolysis Mode,” Proceedings, 6th EUROPEAN SOLID OXIDE FUEL CELL FORUM, 28 June – 2 July 2004, Kultur- und Kongresszentrum Luzern, Lucerne, Switzerland.

Herring, J. S., O’Brien, J. E., Stoots, C. M., Lessing, P. A., Anderson, R. P., Hartvigsen, J. J., and Elangovan, S., “Hydrogen Production from Nuclear Energy via High-Temperature Electrolysis,” Proceedings, 2004 International Conference on Advances in Nuclear Power Plants (ICAPP ‘04), June 13-17, 2004, Pittsburgh, PA, paper no. 4322.

Project ID: PD24 5-25-2005 23

The most significant hydrogen hazard associated with this project is:

Compressed gas handlingHot surfacesHydrogen combustion or explosion hazard

Hydrogen Safety

Project ID: PD24 5-25-2005 24

Our approach to deal with this hazard is:

Independent Hazards ReviewIndependent, laboratory-wide review of operating procedures and safety measuresExperiment designOver-pressure prevention – see experiment schematic, InstrumentationHydrogen DetectorsOn-line (firewall-protected) access to experiment parametersTraining of Project Personnel: Compressed gas training (TRN1041)R&D Laboratory awareness (TRN670)Flammable & combustible materials (SMJS992B)Chemical Hygiene (TRN13)

Hydrogen Safety

High Temperature �Solid Oxide�Electrolyzer SystemOverviewTechnical Barriers�Research Objectives Approach (vs Objectives)HTE FY-05 Task Area OverviewTechnical AccomplishmentsHydrogen Production at 830° COverall hydrogen production efficiencies as a function of power-production thermal efficiency and electrolyzer per-cell operatHTE System Definition�ANL, PIs: Petri, Myers, Carter, YildizTimeline�Project start: Jan ‘03 (DOE-EE)�(became part of the Nuclear Hydrogen Initiative Jan ’04)Supplemental SlidesHydrogen SafetyHydrogen Safety