Advances in Solid Oxide Fuel Cells IX, Volume 34, Issue 4 E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Serie: Ceramic Engineering and Science Proceedings
• Sprache: Englisch

Seitenzahl: 235

Veröffentlichungsjahr: 2013

Beschreibung

Ceramic Engineering and Science Proceedings Volume 34, Issue 4 - Advances in Solid Oxide Fuel Cells IX A collection of 13 papers from The American Ceramic Society's 37th International Conference on Advanced Ceramics and Composites, held in Daytona Beach, Florida, January 27-February 1, 2013. This issue includes papers presented in Symposium 3 - 10th International Symposium on Solid Oxide Fuel Cells: Materials, Science, and Technology.

Leseprobe

Contents

Cover

Half Title page

Title page

Copyright page

Preface

Introduction

Development of a Portable Propane Driven 300 W SOFC-System

Abstract

Introduction

Basic Black Box Considerations

System Concept

Reformer Development

System Setup

Conclusion and Outlook

Acknowledgment

References

SOFC-System for Highly Efficient Power Generation from Biogas

Abstract

Introduction

System Concept

Stack Characterization

Biogas Monitoring and Sulfur Removal

Operation of the SOFC-System

Discussion and Economic Considerations

Summary and Outlook

Acknowledgment

References

Development of Solid Oxide Fuel Cell Stack Modules for High Efficiency Power Generation

Abstract

Introduction

Integrated Gasification Fuel Cell Power Plant System Development

Proof-of-Concept Module System Development

SOFC Technology Development and Module Design

Summary

Acknowledgements

References

The Development of Plasma Sprayed Metal-Supported Solid Oxide Fuel Cells at Institute of Nuclear Energy Research

Abstract

Introduction

Experimental

Results and Disscusion

Conclusion

References

Development and Application of SOFC-MEA Technology at INER

Abstract

Introduction

Experimental

Results and Discussion

Acknowledgement

Reference

Aqueous Processing Routes for New SOFC Materials

Abstract

Introduction

Experimental

Results

Discussion

Conclusions

Acknowledgements

References

Modification of Sintering Behavior of Ni Based Anode Material by Doping for Metal Supported-SOFC

Abstract

Introduction

Materials and Methods

Results and Discussion

Conclusions

Acknowledgements

References

Nickel Pattern Anodes for Studying SOFC Electrochemistry

Abstract

Introduction

Experimental

Results and Discussion

Conclusions

Acknowledgements

References

Assessment of Ba1−xCo0.9−yFeyNb0.1O3−δ for High Temperature Electrochemical Devices

Abstract

Introduction

Material Design for High Tmeperature Electrochemical Devices

Application of Ba1−xCo0.9−yFeyNb0.1O3−δ in High Temperature Electrochemical Devices

Conclusions

Acknowledgements

References

Ionic Conductivity in Mullite and Mullite Type Compounds

Abstract

Introduction

Experimental

Results

Discussion and Conclusions

Acknowledgement

References

Protective Oxide Coatings for the High Temperature Protection of Metallic SOFC Components

Abstract

Introduction

Experimental

Results and Discussion

Conclusion

Acknowledgement

References

Viscous Sealing Glass Development for Solid Oxide Fuel Cells

Abstract

Introduction

Results and Discussion

Conclusion

Acknowledgement

References

Propane Driven Hot Gas Ejector for Anode off Gas Recycling in a SOFC-System

Abstract

Introduction

System Concept

Stack Characterization

Ejector Development

Experiments and Results

Summary and Outlook

Acknowledgement

References

Author Index

Advances in SolidOxide Fuel Cells IX

Cover Design: Wiley

Copyright © 2014 by The American Ceramic Society. All rights reserved.

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ISBN: 978-1-118-80764-4 ISSN: 0196-6219

Preface

The tenth international symposium on Solid Oxide Fuel Cells (SOFC): Materials, Science, and Technology was held during the 37th International Conference and Exposition on Advanced Ceramics and Composites in Daytona Beach, FL, January 27 to February 1, 2013. This symposium provided an international forum for scientists, engineers, and technologists to discuss and exchange state-of-the-art ideas, information, and technology on various aspects of solid oxide fuel cells. A total of 85 papers were presented in the form of oral and poster presentations, including twenty invited lectures, indicating strong interest in the scientifically and technologically important field of solid oxide fuel cells. Authors from 22 countries (Austria, Brazil, Bulgaria, Canada, China, Denmark, Egypt, Estonia, France, Germany, India, Italy, Japan, Netherlands, Norway, Portugal, South Korea, Sweden, Switzerland, Taiwan, United Kingdom, and U.S.A.) participated. The speakers represented universities, industries, and government research laboratories.

These proceedings contain contributions on various aspects of solid oxide fuel cells that were discussed at the symposium. Thirteen papers describing the current status of solid oxide fuel cells materials, Science and technology are included in this volume. Each manuscript was peer-reviewed using the American Ceramic Society review process.

The editors wish to extend their gratitude and appreciation to all the authors for their contributions and cooperation, to all the participants and session chairs for their time and efforts, and to all the reviewers for their useful comments and suggestions. Financial support from the American Ceramic Society is gratefully acknowledged. Thanks are due to the staff of the meetings and publications departments of the American Ceramic Society for their invaluable assistance. Advice, help and cooperation of the members of the symposium’s international organizing committee (J. S. Chung, Tatsumi Ishihara, Nguyen Minh, Mogens Mogensen, J. Obrien, Prabhakar Singh, Jeffry Stevenson, Toshio Suzuki, and Eric Wachsman) at various stages were instrumental in making this symposium a great success.

We hope that this volume will serve as a valuable reference for the engineers, scientists, researchers and others interested in the materials, science and technology of solid oxide fuel cells.

NAROTTAM P. BANSALNASA Glenn Research Center

Mihails KusnezoffFraunhofer IKTS

Introduction

This issue of the Ceramic Engineering and Science Proceedings (CESP) is one of nine issues that has been published based on manuscripts submitted and approved for the proceedings of the 37th International Conference on Advanced Ceramics and Composites (ICACC), held January 27–February 1, 2013 in Daytona Beach, Florida. ICACC is the most prominent international meeting in the area of advanced structural, functional, and nanoscopic ceramics, composites, and other emerging ceramic materials and technologies. This prestigious conference has been organized by The American Ceramic Society’s (ACerS) Engineering Ceramics Division (ECD) since 1977.

The 37th ICACC hosted more than 1,000 attendees from 40 countries and approximately 800 presentations. The topics ranged from ceramic nanomaterials to structural reliability of ceramic components which demonstrated the linkage between materials science developments at the atomic level and macro level structural applications. Papers addressed material, model, and component development and investigated the interrelations between the processing, properties, and microstructure of ceramic materials.

The conference was organized into the following 19 symposia and sessions:

Symposium 1

Mechanical Behavior and Performance of Ceramics and Composites

Symposium 2

Advanced Ceramic Coatings for Structural, Environmental, and Functional Applications

Symposium 3

10th International Symposium on Solid Oxide Fuel Cells (SOFC): Materials, Science, and Technology

Symposium 4

Armor Ceramics

Symposium 5

Next Generation Bioceramics

Symposium 6

International Symposium on Ceramics for Electric Energy Generation, Storage, and Distribution

Symposium 7

7th International Symposium on Nanostructured Materials and Nanocomposites: Development and Applications

Symposium 8

7th International Symposium on Advanced Processing & Manufacturing Technologies for Structural & Multifunctional Materials and Systems (APMT)

Symposium 9

Porous Ceramics: Novel Developments and Applications

Symposium 10

Virtual Materials (Computational) Design and Ceramic Genome

Symposium 11

Next Generation Technologies for Innovative Surface Coatings

Symposium 12

Materials for Extreme Environments: Ultrahigh Temperature Ceramics (UHTCs) and Nanolaminated Ternary Carbides and Nitrides (MAX Phases)

Symposium 13

Advanced Ceramics and Composites for Sustainable Nuclear Energy and Fusion Energy

Focused Session 1

Geopolymers and Chemically Bonded Ceramics

Focused Session 2

Thermal Management Materials and Technologies

Focused Session 3

Nanomaterials for Sensing Applications

Focused Session 4

Advanced Ceramic Materials and Processing for Photonics and Energy

Special Session

Engineering Ceramics Summit of the Americas

Special Session

2nd Global Young Investigators Forum

The proceedings papers from this conference are published in the below nine issues of the 2013 CESP; Volume 34, Issues 2–10:

Mechanical Properties and Performance of Engineering Ceramics and Composites VIII, CESP Volume 34, Issue 2 (includes papers from Symposium 1)

Advanced Ceramic Coatings and Materials for Extreme Environments III, Volume 34, Issue 3 (includes papers from Symposia 2 and 11)

Advances in Solid Oxide Fuel Cells IX, CESP Volume 34, Issue 4 (includes papers from Symposium 3)

Advances in Ceramic Armor IX, CESP Volume 34, Issue 5 (includes papers from Symposium 4)

Advances in Bioceramics and Porous Ceramics VI, CESP Volume 34, Issue 6 (includes papers from Symposia 5 and 9)

Nanostructured Materials and Nanotechnology VII, CESP Volume 34, Issue 7 (includes papers from Symposium 7 and FS3)

Advanced Processing and Manufacturing Technologies for Structural and Multi functional Materials VII, CESP Volume 34, Issue 8 (includes papers from Symposium 8)

Ceramic Materials for Energy Applications III, CESP Volume 34, Issue 9 (includes papers from Symposia 6, 13, and FS4)

Developments in Strategic Materials and Computational Design IV, CESP Volume 34, Issue 10 (includes papers from Symposium 10 and 12 and from Focused Sessions 1 and 2)

The organization of the Daytona Beach meeting and the publication of these proceedings were possible thanks to the professional staff of ACerS and the tireless dedication of many ECD members. We would especially like to express our sincere thanks to the symposia organizers, session chairs, presenters and conference attendees, for their efforts and enthusiastic participation in the vibrant and cutting-edge conference.

ACerS and the ECD invite you to attend the 38th International Conference on Advanced Ceramics and Composites (http://www.ceramics.org/daytona2014) January 26–31, 2014 in Daytona Beach, Florida.

To purchase additional CESP issues as well as other ceramic publications, visit the ACerS-Wiley Publications home page at www.wiley.com/go/ceramics.

SOSHU KIRIHARA, Osaka University, Japan SUJANTO WIDJAJA, Corning Incorporated, USA

Volume Editors August 2013

DEVELOPMENT OF A PORTABLE PROPANE DRIVEN 300 W SOFC-SYSTEM

Andreas Lindermeir, Ralph-Uwe Dietrich, and Christian Szepanski

Clausthaler Umwelttechnik Institut GmbH (CUTEC)Clausthal-Zellerfeld, Germany

ABSTRACT

Portable power generation is expected to be an early and attractive market for the commercialization of SOFC-systems. The competition in this market is strong at costs per kilowatt, but weak in terms of electrical efficiency and fuel flexibility. Propane is considered as attractive fuel because of its decentralized availability and easy adaptability to other well-established hydrocarbons, such as camping gas, LPG or natural gas.

The Lower Saxony SOFC Research Cluster was initiated as network project to bundle the local industrial and research activities on SOFC technology. Goal is the development of a stand-alone power supply demonstrator on the basis of currently available SOFC stack technology. Electrolyte supported cells are deployed because to their good stability and robustness. Possible application areas are engine-independent power generation for recreational vehicles or off-grid power supply of cabins and boats. Further potential markets are industrial applications with a continuous demand for reliable power, e.g. traffic management, measuring systems and off-grid sensors and surveillance equipment. To cover the technical requirements of those applications, the SOFC system should provide the following features:

propane as fuel,

net system electrical power ≥ 300 We,

net system efficiency ≥ 35 %,

compact mass and volume,

time to full load ≤ 4 hours.

Anode offgas recycle in conjunction with a combined afterburner/reforming-unit in counter flow configuration is used for high efficient fuel gas processing without complex water treatment. All main components are in a planar design and stacked to reduce thermal losses and permit a compact set-up.

INTRODUCTION

The Lower Saxony research cluster consists of 5 institutes from the universities of Braunschweig, Hannover, Clausthal, and the University of Applied Sciences Osnabrück and 9 industrial partners. The project is aimed to introduce innovations in component- and system development by an interdisciplinary team of researchers. The consortium adopted the planar design of the SOFC stack to the other high-temperature components like reformer, stack, heat exchanger and afterburner, thus enabling a compact system setup with a high degree of integration. All units are placed on top or below the stack and rigid pipe connections are avoided whenever possible to minimize space requirements and reduce thermal stresses during the heat-up and cool-down phase. In addition, arrangement and connection of the process units has to consider pressure drop and limitations concerning fabrication and system assembly. The high degree of thermal integration in conjunction with the internal recycle of anode offgas promises an electrical system net efficiency above 35 %. That would be remarkable for a small scale system in the power range < 500 W.

BASIC BLACK BOX CONSIDERATIONS

Figure 1. Black box model for proof of feasibility (given input data are formatted italic)

(1)

The heat loss is 300 W for a surface temperature of 50°C and an area of 1.5 m2. The system offgas temperature was calculated by closing the energy balance. The offgas temperature is 121 °C for a cathode air flow rate of 1.2931 g/s (corresponding 60 lN/min). The cathode air blower causes mainly the parasitic electrical demand of the BoP components. Overall, BoP power demand has to be less than 270 We to obtain the demanded electrical net system efficiency of 35 %. For that case, an electrical net power output of 390 W results. Thus, the initial performance goals seem feasible.

Nevertheless, these figures emphasize the impact of heat loss via the surface for small SOFC systems. 27% of the supplied energy are lost in terms of waste heat at 50°C surface temperature; 480 W is the convective heat loss at 65°C surface temperature and the overall energy balance no longer agrees. Additional energy supply would be required to maintain a self-sustaining operation. These simple considerations illustrate the basic necessity of a high degree of thermal integration and the need for internal usage of heat fluxes, what has to be taken into account from the beginning of system design.

SYSTEM CONCEPT

Figure 2 shows a simplified process flow diagram of the proposed system. Propane and anode offgas (AOG) are fed to the reformer. The AOG contains H2O, CO2 and heat from the electrochemical oxidation of the H2 and CO on the SOFC anode. That is used for endothermic steam- and dry-reforming of the propane. The reformer provides the fuel gas for the SOFC stack. The remaining part of the AOG is fed together with the cathode exhaust air to the afterburner for additional heat generation. Heat is used to maintain the endothermic reformer reactions and for cathode air pre heating to about 650 °C, before entering the stack.

Figure 2. Process flow diagram of the propane SOFC system with anode offgas recycle

Hot anode offgas recycling is a challenging task and no commercial hardware solution is currently available for the desired flow range. Thus, a piston pump was proposed and developed for AOG recycle. Intercooling of the anode offgas cannot be fully avoided due to the temperature limitations of the compressor bearings and seals. Thus, reheating the compressed AOG with the hot AOG from the anode exit using a tube-in-tube heat exchanger seems to be a reasonable compromise.

The lower limit of the AOG recycle rate is determined by the carbon formation boundary in the reformer for the given temperature. It is shown in previous tests that the oxygen to carbon ratio at the reformer inlet (O/C)Ref (Equation 2) is the key figure with respect to carbon formation2.

(2)

The parameter (O/C)Ref corresponds to the steam to carbon ratio S/C, well known for steam reforming reactions. Equation 3 and 4 show the strong endothermy of the reforming reactions taken place:

(3)

(4)

Figure 3 shows the equilibrium reformate composition at different temperatures based on stationary process flow sheet simulations (ChemCAD®). The flow rate ratio of AOG to propane has been kept constant at a calculated (O/C)Ref of 1.82. Hydrocarbon conversion is almost complete for reforming temperatures above 700 °C. The fraction of H2 and CO is greater than 60 Vol.-%. Soot formation is inhibited above 720 °C for the distinct operation conditions.

While the reformer and burner can be considered as Gibbs reactors (delivering thermodynamic equilibrium values), the flow sheet simulation of the overall process requires the implementation of a confirmed stack characteristic. Key figures for the stack are power output, fuel utilization and electrochemical efficiency at the desired operation point. Thus, a Staxera Mk200/ESC4 stack was evaluated in a stack-test-bench with different fuel gas compositions and throughputs. Figure 4 shows the measured U/I-curves, Table 1 summarizes the stack performance data for the different operation points.

Figure 4. Single cell U/I-curves, Mk200/ESC4 stack, 850°C stack temperature

Table 1. Experimentally validated stack performance data, Mk200/ESC4 stack, 850 °C stack temperature

The system concept was investigated in steady-state operation with ChemCAD® flow sheet simulations. Figure 5 shows the results in terms of an energy flow chart for one operation point.

Figure 5: Energy flow chart for the stationary design-point

Figure 6 shows a sketch of the assembly concept and a scheme of the gas flows. The main components are enclosed in an inner thermal insulation. Propane enters the system, is mixed with the respective amount of anode offgas delivered by the AOG compressor and fed to the reformer layer. Reformate gas passes the SOFC anode; part of the anode offgas stream is recycled to the reformer inlet, remaining AOG is fed to the catalytic burner that encloses the planar reformer catalyst. The burner exhaust gas enters the heat exchanger for cathode air preheating. Cold cathode inlet air purges the outer casing prior to the entry in the heat exchanger to assure low surface temperatures and thus reduce heat losses through the outer enclosure. The system has only two supply connections, one for the air and propane. Exhaust gas is released by an opening in the outer casing.

Figure 6. Schematic design of component alignment and simplified gas flows

REFORMER DEVELOPMENT

Supplying sufficient heat for the endothermic reforming reactions is a main task to assure a self-sustaining and soot free reformer operation. As shown in Figure 5, a heat flux of about 300 W has to be transferred from the burner section to the reformer to maintain a reforming temperature above 720°C. A commercial metallic foil substrate is used as support for the reformer catalyst because of its good heat conductivity, what assures good heat transfer through- and in-plane. A catalyst with an activity for both, steam- and dry-reforming of propane is required. For the proof of proper catalyst choice, a catalytic coated foil package was mounted in a simple housing. For the preliminary catalyst tests, a five-layer substrate was used as support for the catalytic coating. The assembly was equipped with thermocouples (see Figure 7) and placed inside a furnace, heated up to 850°C and fed with a mixture of propane and a synthetic AOG. The furnace simulates the heat supplied by the anode offgas burner. Reformate gas composition and reformer temperatures are determined for different feed compositions and flow rates. Figure 8 shows the reformer outlet temperature and the methane fraction for different input compositions.

Figure 7. Test set-up for preliminary test of catalytic activity, detail: cross-sectional area of the 5-layer metallic support

Figure 8: Temperature and CH4 concentration (dry basis) at reformer exit with different C3H8 flow rates, furnace temperature: 850°C

The methane fraction can be used as indicator for the degree of conversion. The catalyst is well capable of converting propane if sufficient heat is supplied. For propane flow rates above 0.4 lN/min the reformer temperature falls short of the soot formation boundary. To avoid carbon formation, the tests were terminated at propane flow rates of 0.5 lN/min.

Good conversion rates at low propane throughput and high reforming temperatures show, that the catalyst is suited for a combined steam- and dry-reforming of propane. For further improved heat transfer through-plane a catalyst substrate with only one layer was chosen for the final reformer set-up and coated with the examined catalyst. The substrate foil has a sheet thickness of 50 μm, resulting in a porosity of 400 cpsi (see Figure 9). The foil package has an overall thickness of 1.41 mm.

Figure 9: Single-layer metallic support for the reformer catalyst

The reformer unit was designed as a joint-part coupling the catalytic afterburner and the reformer layer in a sandwich-design, with the catalytic coated reformer substrate located between two burner plates (Figure 10). A commercial oxidation catalyst was used as burner catalyst, arranged as randomly packed bed above and below the reformer unit.

Figure 10: Picture of the reformer-burner-unit in sandwich design with open burner casing

SYSTEM SETUP

Figure 11 shows a 3D-sketch of the complete system setup. Part of the insulation, the stack compression system and the outer casing are removed for a better view. The AOG-compressor together with the tube-in-tube heat exchanger for the AOG is separated from the hot components by a thermal insulation. The reformer-burner-unit is located on top of the SOFC stack with an adapter plate in between to direct the gas streams in the right manner. Another insulation plate separates the stack from the heat exchanger compartment. The plate heat exchanger is designed as two-stage unit, with a low temperature zone made from alumina and a high temperature unit from Crofer22APU. High temperature steel tubes with bellow compensators connects the burner outlet and the heat exchanger inlet. All other components are connected directly or via the adapter plate.

Figure 11: 3D-sketch of the system set-up, parts off insulation, stack compression system and outer casing are removed

CONCLUSION AND OUTLOOK

A concept for a SOFC portable power unit in the power range ≥ 300 We,net using current stack technology has been presented. A simple black box model proves the general feasibility of the approach and indicates, that an electrical net efficiency ≥ 35% is possible using anode offgas recycling and a high level of thermal integration by planar design of the main components promises. The Mk200 stack is well capable of meeting the system requirements and the planar reformer design with a single-layer metal foil as catalyst support and the chosen catalyst has been proven to work under the ambitious conditions of steam-and dry-reforming of propane with AOG. Next step will be the commissioning of the system and the detailed characterisation at different operation points.

ACKNOWLEDGMENT

The authors would like to thank the colleagues from project partners IAL (University of Hannover), InES (University of Braunschweig), IEE, IMET, ISAF (all University of Clausthal) and LAT (University of Applied Sciences Osnabrück).

This work was financed by “European Regional Development Fund” (ERDF). Financial and advisory support by our industrial partners EcoEnergy GmbH, Solvis GmbH & Co KG, H.C. Starck GmbH, LASER on demand GmbH, SIEB & MEYER AG, GEA AG, EWE AG, Staxera GmbH and Elster Kromschröder GmbH is gratefully acknowledged.

REFERENCES

1 Staxera GmbH, Product data sheet Article 284, Dresden, Germany, 2008 http://www.staxera.de/fileadmin/downloads/Mk200/081106_PDS_284-Mk200.pdf

2 S. Chen, C. Schlitzberger, Modeling and Simulation of a Propane SOFC System with Integrated Fuel Reforming Using Recycled Anode Exhaust Gas, Proceedings of the 8th European Solid Oxide Fuel Cell Forum, Luzern, Swiss, 30.6–4.7.2008

3 R.-U. Dietrich, et al., Using anode-offgas recycling for a propane operated solid oxide fuel cell, Proceedings of the 7th ASME Conference on Fuel Cell Science, Engineering & Technology, Newport Beach, California, USA, 8.–10.6.2009

SOFC-SYSTEM FOR HIGHLY EFFICIENT POWER GENERATION FROM BIOGAS

Andreas Lindermeir, Ralph-Uwe Dietrich, and Jana Oelze

Clausthaler Umwelttechnik Institut GmbH (CUTEC)Clausthal-Zellerfeld, Germany

ABSTRACT

Power generation from biogas using motor-driven CHP units has a limited electrical efficiency far below 50%, especially for smaller engines in the power range below 100 kWe. Fluctuating quality and/or low CH4 content reduce operation hours and economical and ecological benefit. On the other hand, solid oxide fuel cell (SOFC) systems promise electrical efficiencies above 50 % even for small-scale units and/or low-calorific biogas. Current development tasks of SOFC stack technology are the scale-up of the power range up to the hundreds of kWe