doe solar hydrogen workshop (2004) - high-temperature electrolysis · pdf file ·...

A U.S. Department of EnergyOffice of Science LaboratoryOperated by The University of Chicago

Argonne National Laboratory

Office of ScienceU.S. Department of Energy

High-Temperature Electrolysis

Richard Doctor, Diana Matonis, Robert LyczkowskiDOE Solar-Hydrogen WorkshopUMUC Conference Center – Adelphi, MD9-10 November 2004

2

Pioneering Science andTechnology

Office of ScienceU.S. Department

of Energy

Heat 1050K

Thermochemical Cycles Electrolysis

S-I UT-3 Cu-Cl Hybrid Systems High T Steam Electrolysis

S-I Ca-Br Cu-Cl

Evaluation of Cycles for Hydrogen Production

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High-Temperature Electrolysis for Hydrogen Production - Materials

• Drivers for High-temperature electrolysis:- Oxygen is the charge carrier, rather than hydrogen – this

requires high temperatures, but no use of strategic metals- Low-footprint for this system, it is adaptable to many scales- Highest efficiency for electrolysis

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of Energy

Higher temperatures for steam electrolysis are one contributor to reduced power demands

Minimum H2O Dissociation Power

0

10

20

30

40

50

60

0 500 1000 1500

Temperature - K

[-]G

ibb

s F

ree

En

ergy

- k

Cal

/gm

-mol

e

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• (1) coordinate with the experimental work at INEEL that will demonstrate the improvements in performance for a high-temperature steam electrolysis system operating at up to 1,000 K and assure that the data required to conduct a detailed process design study are linked into an ASPEN-based process design

• (2) consider the issues affecting the long-term performance of electrolyzer cells in this service

• (3) consider the requirements for producing and handling reagent-grade water that will be employed for these cells, starting from a base of available non-potable water at the production facility site

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• (4) examine the technological features as they link to process economics, surveying what would be needed to achieve commercial viability using these technologies, particularly the appropriate scale of operations

• (5) perform life-cycle emissions evaluations to quantify the reductions that can be achieved by using these technologies.

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OBJECTIVES – High Temperature Electrolysis

• Optimize Hydrogen Production- Choice of process- Optimize materials and operating conditions

• Optimize Overall Plant System- Integrate selected process into balance of plant- Heat Recuperation from product streams

- Perform a energy/pinch analysis- Perform an overall efficiency analysis of plant.

• Cooperative program with INEEL

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Linkage of steam-electrolysis to a solar energy system will improve scalability and economics

Hirsch and Steinfeld, Paul Scheer Institute in

Hydrogen Energy 29, 2004 47-59

Demonstrates very encouraging progress that could be directly applied to steam electrolysis

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Multiple paths for linking steam electrolysis to renewable energy are being pursued

Hirsch and Steinfeld, Paul Scheer Institute

Hydrogen Energy 29, 2004 47-59

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Electrochemistry Model

Thermodynamics Kinetics Mass Transport Energy

ActivationOverpotential

Concentration Overpotential

Heat EffectsOhmic Losses

Butler-Volmer Limiting Current DensityDiffusion (Ficks,S-M,DGM)

OH

OHo P

PP

F

RTEE

2

22

2/1

ln2

+=

System Integration

Standard ReductionOverpotential

Balance of Plant

Material SelectionGeometry

Electrode DesignCharacterization

Current Distribution

Computational Fluid Dynamics

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of Energy

SOFC/SOEC Modeling Overpotential

raCOH

OHo P

PP

F

RTEE ηηη ++++=

2

22

2/1

ln2

Reversible Cell Voltage Overpotential:Concentration, activation and ohmic

.Fuel Cell Mode

Electrolysis

-1.6

-1.4

-1.2

-1

-0.8

-0.6-0.3 -0.2 -0.1 0 0.1 0.2 0.3

cell

po

ten

tial

, V

current density, i A/cm2

E

Eref

T = 800 C; Tdp, i

= 27.4 C

Qs, Ar

= 140 sccm

Qs, H2

= 40 sccm

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of Energy

Button and Stack SOFC/SOEC Experiment

Taken From INEEL report 2004, Steve Herring and Jim O’Brien, “High Temperature Solid

Oxide Electrolyser System”

Porous Anode, Strontium-doped Lanthanum Manganite

Gastight Electrolyte, Yttria-Stabilized Zirconia

Porous Cathode, Nickel-Zirconia cermet

2 H20 + 4 e- → 2 H2 + 2 O=

2 O= → O2 + 4 e-

2 O=

↓

H2O↓ ↑

H2

O2

↓

4 e-→

Interconnection

H2O + H2 →

← Ο2

Next Nickel-Zirconia Cermet CathodeH2O↓

↑H2

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Available Commercial CFD Codes

• Code Selection

ü Femlab

ü Star-CD

ü Fluent

• STARCD

• 350 Node Linux Parallel Cluster at ANL

Ø Calculations based on currentØ Current density establishes rate of

oxygen transport through electrolyte

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V-I Characteristics

( ) ( )

+

++

++++

+= 1log2

321

102

32121 I

AT

tT

ttTsTssI

A

TrrEE rev

E operating cell voltageErev reversible cell voltageR ohmic resistance of electrolytes,t coeff for overvoltage on electrodes

Stand-Alone Power Systems For the Future: Optimal Design, Operating &Controle of Solar-Hydrogen Energy Systems, PhD thesis O. Ulleberg. 1998 Norwegian University of Science and Tch.

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Ohmic Losses•Area Specific Resistance (ASR)

•ASR = thickness/conductivity(ó)

•Voltage Loss due to Ohmic resistance

•V=i*ASR

•Electrolyte offers considerable resistance

•ó(YSZ)=0.3685 +0.002838exp(10300/T)

•Electrodes offer relatively small resistance and are given in literature.

•Many treat as constants

•Anode: 0.0014 Ù-cm

•Cathode: 0.0186 Ù-cm

•Interfacial Resistances: ~0.1 Ù-cm

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Butler –Volmer Aproximation â=0.5 most assume for fuel cells

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INEEL SUPPLIED V-I Curves-1.8

-1.5

-1.2

-0.9

-0.6 -1

-0.7

-0.4

-0.1

0.2

-0.6 -0.4 -0.2 0 0.2

sweep 1sweep 2sweep 3sweep 4sweep 5sweep 6

cell

po

ten

tial

, E (

V)

cell power density, p (A

/cm2)

current density, i ( A/cm2)

fuel cell modeelectrolysis mode

Qs, H2

Qs, Ar

Tdp,i

(C)Tfrn

(C)sweep

40.1141278501

40.1141278002

40.114135.58503

40.114135.58004

40.114138.38505

40.114138.58006

Test Conditions

power density

cell potential

0

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Cathode Concentration Overpotential

AABA xcDscm

molgmJ ∇−=

−2

−−

−=

22

1ln1ln2 HOH i

i

i

i

F

RTV

Using Fick Law of Diffusion

Ô=porosity

= tortuosity

r = molecular radius

τ

Pulsed Gradient Spin Echo NMR measurements of the time-dependent

diffusion coefficient, D(t).

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CFD Simulations will be a very necessary elements of SOEC development

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System Integration

Extra components needed to

-Gases need to be circulated through the stack

-Compressors, pumps or blowers

-Electric motors to drive pumps, blowers and compressor

-Fuel cell needs to connected to load like DC/DC converter for simple voltage regulator as used by INEEL expt.

-Cooling system, air-preheater

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H2 (kW-HHV/kg) = 39.447cost power (kW)

Housing/Forecourt dispenser (NEPA Compliant) $12,000Electric Power Transformer $14,000 0.20 $/W -5% 3.50

Water System-manifolding $1,250 0.10Electric Power Invertor/Conditioning $45,932 0.85 $/W -5% 2.70

Electrolytic Cells ($/kW) $143,199 $2,650 $/kW 73% 54.04Hydrogen Compression (ambient - 100 psi) $20,000 1.05

Hydrogen Compression (100 - 5,000 psi) $78,678 15% 3.60Hydrogen dispensing (5,000 psi) $17,984 0.50

800kW-Natural Gas Compression/Hythane (50 - 3,600 psi) $29,974 2.09800kW-Hythane dispensing (3,600 psi) $11,990 0.50

Oxygen system manifolding $2,500 0.15Controls/Auxiallry $25,585 7.0% 0.80

Cooling fan $1,250 1.4% 0.98Profit $60,657 15.0%

TOTAL $465,000 Power (kWelectric) 70.00

cost basis

Low-temperature Electrolysis – 1 kg/h H2

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High-T Electrolysis Balance of Plant

1025

2.9

2320410

11

1025

2.9

291113

1025

2.9

23204

12

300

3.0

1684

7

542

3.0

1974337

408

3.0

16848418

3.0

1974338 452

3.0

232049

307

3.5

915729414

2.9

3236020

2.8

0

2T

414

2.8

32360

21

325

4.0

1084125

325

4.0

4841

26

325

4.0

6000

40

470

4.0

10841

24

470

4.0

3236022325

4.0

484

28

290

3.5

1200

6

325

4.0

582342

325

4.0

17741

1025

3.0

1683235

1025

3.0

19743

36

290

1.0

17000

30

290

1.0

168

31

290

1.0

16832

32437

3.0

16832

33

1015

3.0

1683234

470

4.0

2152023

290

1.5

60003

290

3.5

6000

4

290

1.5

6000

1

403

2.8

0

2

325

4.0

4357

27290

3.5

4800

5

519

14.0

582343

325

13.7

582344

543

50.3

582345

325

50.0

582346

RSTOIC

B1

Q=401155

SEP

B2

Q=-0

E1

Q=20420

E2

Q=125164

MIXER

B8

D1Q=0

D2

Q=0

E5

Q=-73639

COMP1

W=16007

B14SEP

DRY2Q=-2196

MIXER

B3

SEP

DRY1

Q=-2163

B7

W=20192

E3

Q=84822

E4 Q=1555

B16

B17

B4

W=8

B5

B9

B6 MIXER

B10

B11W=9173

B12 Q=-9162

B18W=10408

B19 Q=-10363

Temperature (K)

Pressure (bar)

Molar Flow Rate (kmol/hr)

Q Duty (kW)

W Power(kW)

Heat @ 1050 K

ReagentH2O

Wet H2

50% Conversion

Stripping Air

Mole sievedryer

O2-richStripping Air Out

Mole sieve dryer

Dry, High Pressure H2

Moisture

Moisture

Normallyno flow

Aspen Plus 12.1 Run:Electrolysis 2004-10-29a 50%H2O-50% Conversion 10/29/2004 11:29:04 AM

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High-temperature Electrolysis – 1 kg/h H2

H2 (kW-HHV/kg) = 33.721Cost Power (kW)

Housing/Forecourt dispenser (NEPA Compliant) $18,000Electric Power Transformer $10,000 0.20 $/W -5% 2.50

Water System-manifolding $500 0.10Steam system $8,000 0.00

Electric Power Invertor/Conditioning $30,820 0.85 $/W -5% 1.81Electrolytic Cells ($/kW) $123,282 $3,400 $/kW 93% 36.26

Hydrogen Compression (ambient - 100 psi) $27,000 1.05Hydrogen Compression (100 - 5,000 psi) $78,678 15% 3.60

Hydrogen dispensing (5,000 psi) $17,984 0.50800kW-Natural Gas Compression/Hythane (50 - 3,600 psi) $29,974 2.09

800kW-Hythane dispensing (3,600 psi) $11,990 0.50Oxygen system manifolding $20,000 0.70

Controls/Auxiallry $25,076 7.0% 1.20Moisture dryers $2,150 0.00

Cooling fan $875 1.4% 0.71Profit $60,671 15.0%

TOTAL $465,000 Power (kW electric) 51.02

Power (kWQ@1050K) 10.66

Cost basis

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Capital Cost Comparison

High-T Low-THousing/Forecourt dispenser (NEPA Compliant) $18,000 $12,000

Electric Power Transformer $10,000 $14,000Water System-manifolding $500 $1,250

Steam system $8,000Electric Power Invertor/Conditioning $30,820 $45,932

Electrolytic Cells ($/kW) $123,282 $143,199Hydrogen Compression (ambient - 100 psi) $27,000 $20,000

Hydrogen Compression (100 - 5,000 psi) $78,678 $78,678Hydrogen dispensing (5,000 psi) $17,984 $17,984

800kW-Natural Gas Compression/Hythane (50 - 3,600 psi) $29,974 $29,974800kW-Hythane dispensing (3,600 psi) $11,990 $11,990

Oxygen system manifolding $20,000 $2,500Controls/Auxiallry $25,076 $25,585

Moisture dryers $2,150Cooling fan $875 $1,250

Profit $60,671 $60,657TOTAL $465,000 $465,000

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Power use comparisonHigh-T Low-T

Housing/Forecourt dispenser (NEPA Compliant)Electric Power Transformer 2.50 3.50

Water System-manifolding 0.10 0.10Steam system 0.00 0.00

Electric Power Invertor/Conditioning 1.81 2.70Electrolytic Cells ($/kW) 36.26 54.04

Hydrogen Compression (ambient - 100 psi) 1.05 1.05Hydrogen Compression (100 - 5,000 psi) 3.60 3.60

Hydrogen dispensing (5,000 psi) 0.50 0.50800kW-Natural Gas Compression/Hythane (50 - 3,600 psi) 2.09 2.09

800kW-Hythane dispensing (3,600 psi) 0.50 0.50Oxygen system manifolding 0.70 0.15

Controls/Auxiallry 1.20 0.80Moisture dryers 0.00 0.00

Cooling fan 0.71 0.98Profit

Power (kWelectric) 51.02 70.00

Power (kWQ@1050K) 10.66 0.00

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Cross-Cutting Research DirectionsØ Membranes and Separation

Ceramic membranes used for the separation of oxygen from air must simultaneously achieve high-flux oxygen transport and equally large electronic transport, and, at the same time, must survive the extreme conditions of the membrane reactor

high temperatures reactive environments highly reducing conditions on one surface of the membrane

Ø Characterization and measurement techniquesAdvanced Photon SourceElectron Microscopy

ØTheory,modeling and simulationDiffusion Models

Continued Interdisciplinary Effort

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Issues with High-Temperature ElectrolysisØ Desirable for product hydrogen to be

produced at high pressures

- Robust cell design necessary

Ø Electrical energy intensive

- High ohmic losses due to thick electrolyte- High strength design needed

- High overpotential on oxygen electrode

- High overpotential and degradation of steam/hydrogen electrode

- High thermodynamic potential to overcome

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Conclusions – High Temperature Electrolysis

• Capital Costs appear competitive• Physical plant footprint will be lager• Premium (Electric) Power demands are much lower• Premium heat demands now needed

doe solar hydrogen workshop (2004) - high-temperature electrolysis · pdf file ·...

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