Model-based Interpretation of the Performance and Degradation of Reformate Fueled Solid Oxide Fuel Cells PDF Download

Author: Alexander Kromp
Publisher: KIT Scientific Publishing
ISBN: 373150006X
Category : Technology & Engineering
Languages : en
Pages : 146

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Book Description
Solid oxide fuel cells offer great prospects for the sustainable, clean and safe conversion of various fuels into electrical energy. In this thesis, the performance-determining loss processes for the cell operation on reformate fuels are elucidated via electrochemical impedance spectroscopy. Model-based analyses reveal the electrochemical fuel oxidation mechanism, the coupling of fuel gas transport and reforming chemistry and the impact of fuel impurities on the degradation of each loss process.

Author: Elinor Parks
Publisher: Routledge
ISBN: 9781000034165
Category : Education
Languages : en
Pages : 0

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Book Description
This volume explores the relationship between language and culture while considering its implications for the teaching of modern foreign languages in higher education. Drawing on a comparative empirical study conducted at universities both in the UK and US, this text problematises the impacts of a separation of language and content in German degree programmes. Illustrating the need for a curriculum which fosters the development of intercultural competence and criticality, Parks reconceptualises established models of criticality (Barnett) and intercultural communicative competence (Byram). The chapters in this volume discuss a range of important topics including; language graduates with deep translingual and transcultural competence, observed differences and similarities between British and American universities and faculty and student voices: developing intercultural competence and criticality. Aimed at scholars with research interests in intercultural communication, language education and applied linguistics, this volume provides a thorough discussion for the ways in which modern language programmes in higher education can be improved. Additionally, those carrying out research in the fields of language teaching and language policy in higher education will find Developing Critical Cultural Awareness in Modern Languages to be of great relevance.

Author: Dario Marra
Publisher: Springer
ISBN: 1447156587
Category : Technology & Engineering
Languages : en
Pages : 174

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Book Description
This book presents methodologies suitable for the optimal design of control and diagnosis strategies for Solid Oxide Fuel Cell (SOFC) systems. One key feature of the methodologies presented is the use of modeling tools with an ideal balance between accuracy and computational burden. Particular emphasis is given to the useful combination of models within a hierarchical framework to reduce the experimental efforts required for characterization and testing. Such tools are proven to be highly effective for SOFC systems destined for both residential and transportation applications. Throughout the book, optimization is always conceived in such a way so as to allow the SOFC systems to work efficiently while guaranteeing safe thermal operation, as well as an extended lifetime. This book is aimed at scientists and engineers involved in the design of marketable SOFC systems. It gathers the knowledge and experience derived from other research and industry practice for which control and diagnosis have proven to be the main keys to success and market penetration.

Author: Geisler, Helge Ingolf
Publisher: KIT Scientific Publishing
ISBN: 3731508958
Category : Technology & Engineering
Languages : en
Pages : 292

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Book Description
This work presents a numerical FEM framework, capable of predicting SOFC performance under technically relevant, planar stack contacting conditions. A high level of confidence in the model predictions is supplied by using exclusively experimentally determined material/kinetic parameters and by a comprehensive validation. The presented model aids SOFC stack development by pre-evaluating possible material choices and design combinations for cells/interconnectors without any experimental effort.

Author: Joos, Jochen
Publisher: KIT Scientific Publishing
ISBN: 3731506254
Category : Technology (General)
Languages : en
Pages : 246

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Book Description
This work deals with microstructural characterisation, modelling and simulation of SOFC electrodes with the goal of optimizing the electrode microstructures. Methods for a detailed electrode analysis based on focused ion beam (FIB) tomography are presented. A 3D FEM model able to perform simulations of LSCF cathodes based on 3D tomography data is shown. A model generating realistic, yet synthetic microstructures is presented that enables the optimization of microstructural characteristics.

Author: Niedrig, Christian
Publisher: KIT Scientific Publishing
ISBN: 3731504375
Category : Technology (General)
Languages : en
Pages : 206

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Book Description
Mixed ionic-electronic conducting (MIEC) ceramics as oxygen transport membranes (OTMs) can provide high oxygen permeation rates at comparably low energy demands. For this purpose, Ba?.?Sr?.?Co?.?Fe?.?O??? (BSCF) shows the best performance under ideal operating conditions. Thermal and chemical stability investigations, electrical behavior ?(T,pO?,t), and oxygen exchange parameter extraction by means of electrical conductivity relaxation resulted in a far better understanding of the BSCF system.

Author: Illig, Joerg
Publisher: KIT Scientific Publishing
ISBN: 3731502461
Category : Technology & Engineering
Languages : en
Pages : 231

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Book Description
In this book, a new procedure to analyze lithium-ion cells is introduced. The cells are disassembled to analyze their components in experimental cell housings. Then, Electrochemical Impedance Spectroscopy, time domain measurements and the Distribution function of Relaxation Times are applied to obtain a deep understanding of the relevant loss processes. This procedure yields a notable surplus of information about the electrode contributions to the overall internal resistance of the cell.

Author: Debanjan Das
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The Pennsylvania State University The Graduate School Department of Energy & Mineral Engineering ELECTROCHEMICAL DEGRADATION, KINETICS & PERFORMANCE STUDIES OF SOLID OXIDE FUEL CELLS BY LINEAR AND NON-LINEAR FREQUENCY TECHNIQUES A Dissertation in Energy & Mineral Engineering by Debanjan Das © 2016 Debanjan Das Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy May 2016 The Dissertation of Debanjan Das was reviewed and approved* by the following: Serguei N. Lvov Professor of Energy and Mineral Engineering & Materials Science and Engineering, Director of Electrochemical Technologies Program Dissertation Adviser Chair of Committee Derek Elsworth Professor of Energy and Mineral Engineering Sarma Pisupati Professor of Energy & Mineral Engineering Michael Janik Associate Professor of Chemical Engineering Luis F. Ayala Associate Professor of Petroleum and Natural Gas Engineering Associate Department Head for Graduate Education * Signatures are on file in the Graduate School Abstract Linear and Non-linear electrochemical characterization techniques and equivalent circuit modelling were carried out on miniature and sub-commercial Solid Oxide Fuel Cell (SOFC) stacks as an in-situ diagnostic approach to evaluate and analyze their performance under the presence of simulated alternative fuel conditions. The main focus of the study was to track the change in cell behavior and response live, as the cell was generating power. Electrochemical Impedance Spectroscopy (EIS) was the most important linear AC technique used for the study. The distinct effects of inorganic components usually present in hydrocarbon fuel reformates on SOFC behavior have been determined, allowing identification of possible "fingerprint" impedance behavior corresponding to specific fuel conditions and reaction mechanisms. Critical electrochemical processes and degradation mechanisms which might affect cell performance were identified and quantified. Sulfur and siloxane cause the most prominent degradation and the associated electrochemical cell parameters such as Gerisher and Warburg elements are applied respectively for better understanding of the degradation processes. Electrochemical Frequency Modulation (EFM) was applied for kinetic studies in SOFCs for the very first time for estimating the exchange current density and transfer coefficients. EFM is a non-linear in-situ electrochemical technique conceptually different from EIS and is used extensively in corrosion work, but rarely used on fuel cells till now. EFM is based on exploring information obtained from non-linear higher harmonic contributions from potential perturbations of electrochemical systems, otherwise not obtained by EIS. The baseline fuel used was 3 % humidified hydrogen with a 5-cell SOFC sub-commercial planar stack to perform the analysis. Traditional methods such as EIS and Tafel analysis were carried out at similar operating conditions to verify and correlate with the EFM data and ensure the validity of the obtained information. The obtained values closely range from around 11 mA cm-2 - 16 mA cm-2 with reasonable repeatability and excellent accuracy. The potential advantages of EFM compared to traditional methods were realized and our primary aim at demonstrating this technique on a SOFC system are presented which can act as a starting point for future research efforts in this area. Finally, an approach based on in-situ State of Health tests by EIS was formulated and investigated to understand the most efficient fuel conditions for suitable long term operation of a solid oxide fuel cell stack under power generation conditions. The procedure helped to reflect the individual effects of three most important fuel characteristics CO/H2 volumetric ratio, S/C ratio and fuel utilization under the presence of a simulated alternative fuel at 0.4 A cm-2. Variation tests helped to identify corresponding electrochemical/chemical processes, narrow down the most optimum operating regimes considering practical behavior of simulated reformer-SOFC system arrangements. At the end, 8 different combinations of the optimized parameters were tested long term with the stack, and the most efficient blend was determined.

Author: Bin Zhu
Publisher: John Wiley & Sons
ISBN: 3527812784
Category : Technology & Engineering
Languages : en
Pages : 488

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Book Description
Presents innovative approaches towards affordable, highly efficient, and reliable sustainable energy systems Written by leading experts on the subject, this book provides not only a basic introduction and understanding of conventional fuel cell principle, but also an updated view of the most recent developments in this field. It focuses on the new energy conversion technologies based on both electrolyte and electrolyte-free fuel cells?from advanced novel ceria-based composite electrolyte low temperature solid oxide fuel cells to non-electrolyte fuel cells as advanced fuel-to-electricity conversion technology. Solid Oxide Fuel Cells: From Electrolyte-Based to Electrolyte-Free Devices is divided into three parts. Part I covers the latest developments of anode, electrolyte, and cathode materials as well as the SOFC technologies. Part II discusses the non-electrolyte or semiconductor-based membrane fuel cells. Part III focuses on engineering efforts on materials, technology, devices and stack developments, and looks at various applications and new opportunities of SOFC using both the electrolyte and non-electrolyte principles, including integrated fuel cell systems with electrolysis, solar energy, and more. -Offers knowledge on how to realize highly efficient fuel cells with novel device structures -Shows the opportunity to transform the future fuel cell markets and the possibility to commercialize fuel cells in an extended range of applications -Presents a unique collection of contributions on the development of solid oxide fuel cells from electrolyte based to non-electrolyte-based technology -Provides a more comprehensive understanding of the advances in fuel cells and bridges the knowledge from traditional SOFC to the new concept -Allows readers to track the development from the conventional SOFC to the non-electrolyte or single-component fuel cell Solid Oxide Fuel Cells: From Electrolyte-Based to Electrolyte-Free Devices will serve as an important reference work to students, scientists, engineers, researchers, and technology developers in the fuel cell field.

Author: Nigel Brandon
Publisher: Academic Press
ISBN: 0128097248
Category : Technology & Engineering
Languages : en
Pages : 235

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Book Description
Solid Oxide Fuel Cell Lifetime and Reliability: Critical Challenges in Fuel Cells presents in one volume the most recent research that aims at solving key issues for the deployment of SOFC at a commercial scale and for a wider range of applications. To achieve that, authors from different regions and backgrounds address topics such as electrolytes, contaminants, redox cycling, gas-tight seals, and electrode microstructure. Lifetime issues for particular elements of the fuel cells, like cathodes, interconnects, and fuel processors, are covered as well as new materials. They also examine the balance of SOFC plants, correlations between structure and electrochemical performance, methods for analysis of performance and degradation assessment, and computational and statistical approaches to quantify degradation. For its holistic approach, this book can be used both as an introduction to these issues and a reference resource for all involved in research and application of solid oxide fuel cells, especially those developing understanding in industrial applications of the lifetime issues. This includes researchers in academia and industrial R&D, graduate students and professionals in energy engineering, electrochemistry, and materials sciences for energy applications. It might also be of particular interest to analysts who are looking into integrating SOFCs into energy systems. Brings together in a single volume leading research and expert thinking around the broad topic of SOFC lifetime and durability Explores issues that affect solid oxide fuel cells elements, materials, and systems with a holistic approach Provides a practical reference for overcoming some of the common failure mechanisms of SOFCs Features coverage of integrating SOFCs into energy systems