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Closing the Carbon Cycle: Fuels from Air, Phoenix, 29/9-2016

Theis L. Skafte (1,2), P. Blennow (1), J. Hjelm (2), and C. Graves (2)

Carbon formation during conversion of CO2 to synthetic fuels by means of electrolysis

(1) Haldor Topsoe A/S, Haldor Topsøes Allé 1, 2800 Kgs. Lyngby, Denmark

(2) Department of Energy Conversion and Storage, Technical University of Denmark, Risø campus, Frederiksborgvej 399, 4000 Roskilde, Denmark

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Outline

• Haldor Topsoe in brief

• Introduction- SOEC, potential usage

- Demonstrations

- Motivation

- Carbon during electrolysis

• The carbon threshold

• 3 scenarios

• Conclusions

• Haldor Topsoe in brief

• Introduction

• The carbon threshold- The method briefly

- Cell-level

- Stack-level

• 3 scenarios

• Conclusions

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Haldor Topsoe

• Established in 1940 by Dr. Haldor Topsøe.

• Private 100% family-owned company.

• Market leader in heterogeneous catalysis and surface science for more than 75 years.

• Ammonia

• Methanol

• HyCO (syngas)

• 2,600 employees in 10 countries.

• Headquarters in Copenhagen, Denmark.

• Production in Frederikssund, Denmark, Houston, USA, and Tianjin, China.

• Spends around 10% of revenue on R&D.

2015 revenue DKK 5,785m (~USD 850m)

2015 operating profit DKK 502m (~USD 75m)

In brief

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

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IntroductionSolid oxide electrolysis - potential usage

Water electrolysis

2 H2O → 2 H2 + O2

• H2 can be used directly or indirectly for e.g. biogas upgrading

CO2 electrolysis

2 CO2 → 2 CO + O2

• CO2 from flue gas stream or air

• Can be used for CO and O2 production

Co-electrolysis

CO2 + H2O → H2 + CO + O2

• Syngas (H2 + CO) can be converted into CO2-neutral transportation fuel (CH4, diesel, etc.)

Graves et al., Solid State Ionics, (2011)

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

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IntroductionDemonstrations

• Synergy between SOC technology and catalysis competencies• Gas more interesting

than electrons

• Demonstration of technology

• Stepping stones until market is ready

EUDP project: Electrolysis Upgraded Biogas –a 50 kW SOEC system

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

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IntroductionMotivation

Lifetime = Degradation mechanisms + failure mechanisms

High efficiency → High CO fraction → Carbon formation on Ni

Low cost

raw materials lifetime efficiency

Offgridworld.com

+ =

“market pull” vs. “society pull”

Price of CO2 emission vs. value of CO2 utilization

“There has to be a business!”

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

Rostrup-nielsen, J. R..,Catalysis Today, 272, (2016)

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Introduction

• 2 CO2 → 2 CO + O2

• 2 CO CO2 + C (Boudouard reaction)

a) In the safe window b) Optimize efficiency c) Outside safe window

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

Carbon during electrolysis

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The carbon thresholdThe method briefly

Skafte et al., ECS Trans., 68 (2015)

YSZ electrolyte

Ni/YSZ electrode

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

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The carbon thresholdCell-level

Current Porosity

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

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Stack-levelThe carbon threshold

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

Gradients, cell

Gradients, stackSteel components

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Scenario a) - Safe

Cell-level Stack-level

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

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Scenario b) - Accidents

YSZ electrolyte

Ni/YSZ electrode

YSZ electrolyte

Ni/YSZ electrode

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

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Scenario b) - Accidents

Irvine, J. T. S et al., Nature Energy, 1(1), (2016) Skafte et al., in preparation

YSZ electrolyte

Ni/YSZ electrode

COCO2

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

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Scenario c) - Unsafe

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

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Scenario c) - Unsafe

YSZ electrolyte

Irvine, J. T. S et al., Nature Energy, 1(1), (2016)

CO

CO2

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

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Scenario c) - Unsafe

• “Sulfur passivation” – J.R. Rostrup-Nielsen

J. R. Rostrup-Nielsen, J. Catal., 85 (1984)

6 ppb for 1 min 100 ppb for 50+ h

Irvine, J. T. S et al., Nature Energy, 1(1), (2016)

CO

CO2

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

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Scenario c) - Unsafe

Get rid of Ni!

Skafte et al., ECS Trans., 72(7), (2016) Graves et al., ECS Trans., 72(7), (2016)

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

750 ℃, pCO 0.9

Ni cell

Non-Ni cell

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Conclusions

1) CO2 reduction in SOEC works and the technology is ready!It is now a matter of reducing costs..

2) Carbon deposition and sulfur poisoning are more problematic issues than expected in full cells and stacks.

3) To optimize efficiency further, Ni-free catalyst is needed!

• HTAS | • • • • Introduction | • • • Carbon threshold | • • • • • • • Scenarios | • Conclusions

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Thank you for your attention!

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Backup slides

References:[1] Graves, C., Ebbesen, S. D., & Mogensen, M., Co-electrolysis of CO2 and H2O in solid oxide cells: Performance and durability, Solid StateIonics, 192(1), 398-403, (2011).

[2] Rostrup-nielsen, J. R., 50 years in catalysis, Lessons learned, Catalysis Today, 272, 2–5, (2016).

[3] Skafte, T. L., Graves, C., Blennow, P., & Hjelm, J., Carbon Deposition during CO2 Electrolysis in Ni-Based Solid-Oxide-Cell Electrodes, ECSTransactions, 68, 3429–3437, (2015).

[4] Irvine, J. T. S., Neagu, D., Verbraeken, M. C., Chatzichristodoulou, C., Graves, C., & Mogensen, M. B., Evolution of the electrochemicalinterface in high-temperature fuel cells and electrolysers, Nature Energy, 1(1), 15014 (2016).

[5] J. R. Rostrup-Nielsen, Sulfur-passivated nickel catalysts for carbon-free steam reforming of methane, J. Catal., 85, 31–43, (1984).

[5] Skafte, T. L., Sudireddy, B. R., Blennow, P., & Graves, C., Carbon and Redox Tolerant Infiltrated Oxide Fuel-Electrodes for Solid OxideC6lls, ECS Transactions, 72(7), 201–214, (2016).

[7] Graves, C., Martinez, L., & Sudireddy, B. R., High Performance Nano-Ceria Electrodes for Solid Oxide Cells, ECS Transactions, 72(7), 183–192 (2016).

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Extra

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Topsoe Stack Platform (TSP-1)75 cells combined with interconnects, spacers and sealings in one stack

• Internal fuel manifold

• External air manifold

• Cell group voltage probing

• Compression free handling (cold)

• Robustness and leak tightness QA test in SOFC mode