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Sample records for sofc hotbox design

  1. Manufacturing of cells and stacks for SOFC development, test and demonstration projects and SOFC hotbox design development

    Energy Technology Data Exchange (ETDEWEB)

    2008-09-15

    The purpose of this project is to support the continued SOFC development through manufacturing process optimization and manufacturing of SOFC cells and stacks. These cells and stacks will serve as a necessary base for the development activities and for the establishment of a number of test and demonstration activities. The manufacture will also help provide operating experience and reduce manufacturing cost. Another main focus of the manufacturing is to assure technical improvements and reliability. It is imperative to the eventual success of the technology that test and demonstration is carried out in the pre-market conditions that will exist for the next years in the three market segments targeted by TOFC (Distributed generation, micro CHP and APU incl. marine APU). Finally, the project also includes development activities focusing on the stack-system interface (hotbox design development) and on dealing with transients and start up and shut down times, which is of particular importance for APU and micro CHP applications. Three topics are addressed:1) Cell manufacture, including production development, capacity lift and manuf. of cells for test and demonstration; 2) Stack manufacture and test, including a test facility, stack manuf. and test of stacks in a system at HCV; 3) Hotbox design development, including design, prototype construction and testing. The progress of this project is documented. Major achievements are successful manufacture of adequate amounts of cells and stacks according to the application. Furthermore significant over-performance in design, construction and test of a methanol based hotbox prototype as well as publication of this. (au)

  2. Final design proposal: Theta Group-The Hotbox. A proposal in response to a commercial air transportation study

    Science.gov (United States)

    1991-01-01

    The Hotbox is a 40 passenger commercial aircraft designed to have a minimum range of 5500 ft and cruise at a velocity of 30 ft/sec. The aircraft is designed to serve the longer range overseas market in Aeroworld. In order to serve all the airports in the overseas market, the Hotbox was required to be able to use a five foot gate. A weight requirement was set a 4.5 lbs in order to maximize aircraft efficiency. Finally, a single engine system was chosen because it minimized system weight, complexity and cost. The Hotbox is estimated to cost $152,000 Aeroworld dollars and will sell for $200.000. The propulsion system for the Hotbox consists of a nose mounted Astro 15 electric powered motor and a Top Flight 12-6 propeller. A Spica airfoil was selected for the Hotbox based on the ease of construction of its flat bottom and its positive lift and drag characteristics. A fuselage of rectangular cross section will internally contain the propulsion system, control system, and a passenger bay with 2x20 seating. A combination of directional and longitudinal control will enable the Hotbox to maneuver. The final design of the Hotbox provides for takeoff distance in 26.5 ft and normal cruise range of 17,000 ft.

  3. Production and Reliability Oriented SOFC Cell and Stack Design

    DEFF Research Database (Denmark)

    Hauth, Martin; Lawlor, Vincent; Cartellieri, Peter

    2017-01-01

    The paper presents an innovative development methodology for a production and reliability oriented SOFC cell and stack design aiming at improving the stacks robustness, manufacturability, efficiency and cost. Multi-physics models allowed a probabilistic approach to consider statistical variations...... in production, material and operating parameters for the optimization phase. A methodology for 3D description of spatial distribution of material properties based on a random field models was developed and validated by experiments. Homogenized material models on multiple levels of the SOFC stack were...... and output parameters and to perform a sensitivity analysis were developed and implemented. The capabilities of the methodology is illustrated on two practical cases....

  4. Market orientated design studies for SOFC based systems

    Energy Technology Data Exchange (ETDEWEB)

    Nietsch, T.; Clark, J.

    1999-07-01

    This report examines the development status of Solid Oxide Fuel Cell (SOFC) technology, assesses its commercial potential for heat and power generation in the UK and identifies key development areas for both the SOFC stack and associated system components. A range of Distributed Generation (DG) and Combined Heat and Power (CHP) applications were considered in arriving at these recommendations. The project commenced with initial surveys of leading SOFC technology companies and centres world-wide. These surveys were conducted in parallel with consultations with key operator organisations in the UK which enabled the requirements of these organisations within the UK Energy Supply Industry to be identified. As a result of the initial survey, over 30 fuel cell based power plants, of size ranging from 1 kW{sub e} to 20 MW{sub e} for both DG and CHP applications, were identified. Outline designs of these applications were then set up and simulated. These candidate systems were then assessed against each other in terms of efficiency, cost of electricity, specific costs, technical risk and market potential for the UK industry. The final ranking obtained was then confirmed with the key operator organisations. On the basis of the ranking process noted above, nine SOFC based power generation/CHP applications were chosen for more detailed investigation in terms of their potential in both UK and overseas markets. Detailed simulations were conducted for each application to allow study of: the influence of efficiency on the economics of the different plants/stacks; the combination of stack and Balance of Plant (BoP) costs; and the cost and availability of key balance of plant devices. These systems were then again assessed in terms of the criteria noted for the outline stage. Finally key development areas for both SOFC stacks and associated Balance of Plant devices were identified. (author)

  5. Progress in the planar CPn SOFC system design verification

    Energy Technology Data Exchange (ETDEWEB)

    Elangovan, S.; Hartvigsen, J.; Khandkar, A. [SOFCo, Salt Lake City, UT (United States)

    1996-04-01

    SOFCo is developing a high efficiency, modular and scaleable planar SOFC module termed the CPn design. This design has been verified in a 1.4 kW module test operated directly on pipeline natural gas. The design features multistage oxidation of fuel wherein the fuel is consumed incrementally over several stages. High efficiency is achieved by uniform current density distribution per stage, which lowers the stack resistance. Additional benefits include thermal regulation and compactness. Test results from stack modules operating in pipeline natural gas are presented.

  6. Design, Operation and Control Modelling of SOFC/GT Hybrid Systems

    OpenAIRE

    Stiller, Christoph

    2006-01-01

    This thesis focuses on modelling-based design, operation and control of solid oxide fuel cell (SOFC) and gas turbine (GT) hybrid systems. Fuel cells are a promising approach to high-efficiency power generation, as they directly convert chemical energy to electric work. High-temperature fuel cells such as the SOFC can be integrated in gas turbine processes, which further increases the electrical efficiency to values up to 70%. However, there are a number of obstacles for safe operation of such...

  7. Cold start dynamics and temperature sliding observer design of an automotive SOFC APU

    Science.gov (United States)

    Lin, Po-Hsu; Hong, Che-Wun

    This paper presents a dynamic model for studying the cold start dynamics and observer design of an auxiliary power unit (APU) for automotive applications. The APU is embedded with a solid oxide fuel cell (SOFC) stack which is a quiet and pollutant-free electric generator; however, it suffers from slow start problem from ambient conditions. The SOFC APU system equips with an after-burner to accelerate the start-up transient in this research. The combustion chamber burns the residual fuel (and air) left from the SOFC to raise the exhaust temperature to preheat the SOFC stack through an energy recovery unit. Since thermal effect is the dominant factor that influences the SOFC transient and steady performance, a nonlinear real-time sliding observer for stack temperature was implemented into the system dynamics to monitor the temperature variation for future controller design. The simulation results show that a 100 W APU system in this research takes about 2 min (in theory) for start-up without considering the thermal limitation of the cell fracture.

  8. Design of a SOFC/GT/SCs hybrid power system to supply a rural isolated microgrid

    International Nuclear Information System (INIS)

    Camblong, Haritza; Baudoin, Sylvain; Vechiu, Ionel; Etxeberria, Aitor

    2016-01-01

    Highlights: • A novel SOFC/GT/SCs HPS is connected to a rural microgrid through a 3LNPC inverter. • An operating strategy that maintains the SOFC power at its rated value is defined. • A robust digital controller that damps current oscillations is designed. • The efficiency, power quality, lifetime, and robustness of the HPS are considered. • An experimental test on an original HPS emulator validates the proposed solutions. - Abstract: The aim of this research study has been to design a Hybrid Power System (HPS) which works with biogas and whose main components are a Solid Oxide Fuel Cell (SOFC), a Gas microTurbine (GT), and a module of SuperCapacities (SCs). The HPS is the only power source of a rural isolated microgrid. Its structure, operating strategy, and controller have been designed considering the following criteria: efficiency, power quality, SOFC lifetime and robustness in stability and performance. The HPS structure includes a unique power converter, a 3-Level Neutral Point Clamped (3LNPC) inverter that connects the HPS to the AC microgrid. Regarding the selected operating strategy, it consists in regulating the SOFC power output to its rated value. Thus, the SCs and the GT must respond to the power demand variations. On the other hand, a study of the HPS shows that its dynamic behavior is not linear. Therefore, a special attention is put on designing a robust HPS controller. The control model is identified and the robust digital controller is designed using the “Tracking and Regulation with Independent Objectives” method. Simulation and experimental results show how the proposed structure, operating strategy, and controller allow ensuring a good behavior of the HPS from the point of view of the abovementioned four criteria.

  9. Design, integration and demonstration of a 50 W JP8/kerosene fueled portable SOFC power generator

    Science.gov (United States)

    Cheekatamarla, Praveen K.; Finnerty, Caine M.; Robinson, Charles R.; Andrews, Stanley M.; Brodie, Jonathan A.; Lu, Y.; DeWald, Paul G.

    A man-portable solid oxide fuel cell (SOFC) system integrated with desulfurized JP8 partial oxidation (POX) reformer was demonstrated to supply a continuous power output of 50 W. This paper discusses some of the design paths chosen and challenges faced during the thermal integration of the stack and reformer in aiding the system startup and shutdown along with balance of plant and power management solutions. The package design, system capabilities, and test results of the prototype unit are presented.

  10. Full load synthesis/design optimization of a hybrid SOFC-GT power plant

    International Nuclear Information System (INIS)

    Calise, F.; Dentice d' Accadia, M.; Vanoli, L.; Spakovsky, Michael R. von

    2007-01-01

    In this paper, the optimization of a hybrid solid oxide fuel cell-gas turbine (SOFC-GT) power plant is presented. The plant layout is based on an internal reforming SOFC stack; it also consists of a radial gas turbine, centrifugal compressors and plate-fin heat exchangers. In the first part of the paper, the bulk-flow model used to simulate the plant is presented. In the second part, a thermoeconomic model is developed by introducing capital cost functions. The whole plant is first simulated for a fixed configuration of the most important synthesis/design (S/D) parameters in order to establish a reference design configuration. Next a S/D optimization of the plant is carried out using a traditional single-level approach, based on a genetic algorithm. The optimization determined a set of S/D decision variable values with a capital cost significantly lower than that of the reference design, even though the net electrical efficiency for the optimal configuration was very close to that of the initial one. Furthermore, the optimization procedure dramatically reduced the SOFC active area and the compact heat exchanger areas

  11. The Design of Connection Solid Oxide Fuel Cell (SOFC) Integrated Grid with Three-Phase Inverter

    Science.gov (United States)

    Darjat; Sulistyo; Triwiyatno, Aris; Thalib, Humaid

    2018-03-01

    Fuel cell technology is a relatively new energy-saving technology that has the potential to replace conventional energy technologies. Among the different types of generation technologies, fuel cells is the generation technologies considered as a potential source of power generation because it is flexible and can be placed anywhere based distribution system. Modeling of SOFC is done by using Nernst equation. The output power of the fuel cell can be controlled by controlling the flow rate of the fuels used in the process. Three-phase PWM inverter is used to get the form of three-phase voltage which same with the grid. In this paper, the planning and design of the SOFC are connected to the grid.

  12. Mechanical characterisation at nanometric scale of a new design of SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Roa, J.J.; Morales, M.; Segarra, M. [Department of Materials Science and Metallurgical Engineering, University of Barcelona, 08028 Barcelona (Spain); Ruiz-Morales, J.C.; Nunez, P. [Department of Inorganic Chemistry, University of La Laguna, 38200 Tenerife (Spain); Canales-Vazquez, J. [Renewable Energies Research Institute, Albacete Science and Technology Park, University of Castilla la Mancha, 02006 Albacete (Spain); G Capdevila, X. [Centre of Design and Optimisation of Processes and Materials, Parc Cientific of Barcelona, 08028 Barcelona (Spain)

    2011-02-15

    The mechanical stability is an important parameter to gain knowledge in the potential applications of a novel design of electrolyte-supported SOFC, based on yttria-stabilised zirconia (YSZ) and NiO-YSZ composites, with cross-linked channels ({proportional_to}90 {mu}m of diameter). In this experimental work, the mechanical properties (hardness, H and Young's modulus, E) at different applied loads have been studied using the nanoindentation technique and the equivalent indenter method. On the other hand, the different fracture mechanisms have been determined using atomic force microscopy (AFM), observing the plastic behaviour that takes place during the indentation process. H value for YSZ is higher than that for NiO-YSZ, while E values for YSZ and NiO-YSZ are 260 {+-} 15 and 205 {+-} 20 GPa, respectively. Only YSZ samples present several radial cracks at the corners nucleated by sharp indentation, thus indicating that H values have been underestimated. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Current progress in the design and setup of a SOFC/GT hybrid power plant

    OpenAIRE

    Schnegelberger, Christian; Henke, Moritz; Tomberg, Marius; Heddrich, Marc; Friedrich, K. Andreas

    2017-01-01

    The German Aerospace Center (DLR) is setting up a hybrid power plant with 30 kW electrical power output. It consists of a SOFC and a micro gas turbine (MGT). The hybrid power plant can reach electrical system efficiencies greater than 60 % throughout a wide operating range. Due to the SOFC’s high operation temperature and incomplete fuel utilisation, the exhaust gas will always contain usable energy. The MGT will use this energy to provide compressed and preheated air for the SOFC and ge...

  14. Impact of cell design and operating conditions on the performances of SOFC fuelled with methane

    Science.gov (United States)

    Laurencin, J.; Lefebvre-Joud, F.; Delette, G.

    An in-house-model has been developed to study the thermal and electrochemical behaviour of a planar SOFC fed directly with methane and incorporated in a boiler. The usual Ni-YSZ cermet has been considered for the anode material. It has been found that methane reforming into hydrogen occurs only at the cell inlet in a limited depth within the anode. A sensitivity analysis has allowed establishing that anode thicknesses higher than ∼400-500 μm are required to achieve both the optimal methane conversion and electrochemical performances. The direct internal reforming (DIR) mechanisms and the impact of operating conditions on temperature gradients and SOFC electrical efficiencies have been investigated considering the anode supported cell configuration. It has been shown that the temperature gradient is minimised in the autothermal mode of cell operation. Thermal equilibrium in the stack has been found to be strongly dependent on radiative heat losses with the stack envelope. Electrochemical performance and cell temperature maps have been established as a function of methane flow rates and cell voltages.

  15. Diesel Fueled SOFC for Class 7/Class 8 On-Highway Truck Auxiliary Power

    Energy Technology Data Exchange (ETDEWEB)

    Vesely, Charles John-Paul [Cummins Power Generation; Fuchs, Benjamin S. [Cummins Power Generation; Booten, Chuck W. [Protonex Technology, LLC

    2010-03-31

    The following report documents the progress of the Cummins Power Generation (CPG) Diesel Fueled SOFC for Class 7/Class 8 On-Highway Truck Auxiliary Power (SOFC APU) development and final testing under the U.S. Department of Energy (DOE) Energy Efficiency and Renewable Energy (EERE) contract DE-FC36-04GO14318. This report overviews and summarizes CPG and partner development leading to successful demonstration of the SOFC APU objectives and significant progress towards SOFC commercialization. Significant SOFC APU Milestones: Demonstrated: Operation meeting SOFC APU requirements on commercial Ultra Low Sulfur Diesel (ULSD) fuel. SOFC systems operating on dry CPOX reformate. Successful start-up and shut-down of SOFC APU system without inert gas purge. Developed: Low cost balance of plant concepts and compatible systems designs. Identified low cost, high volume components for balance of plant systems. Demonstrated efficient SOFC output power conditioning. Demonstrated SOFC control strategies and tuning methods.

  16. The ways of SOFC systems efficiency increasing

    Energy Technology Data Exchange (ETDEWEB)

    Demin, A.K.; Timofeyeva, N.

    1996-04-01

    The efficiency of solid oxide fuel cells (SOFCs) is described. This paper considers methods to lift the fuel utilization and/or the average cell voltage with the goal of increasing the cell efficiency by improved cell designs.

  17. Optimal Design and Operation of A Syngas-fuelled SOFC Micro-CHP System for Residential Applications in Different Climate Zones in China

    DEFF Research Database (Denmark)

    Yang, Wenyuan; Liso, Vincenzo; Zhao, Yingru

    2013-01-01

    heat-to-power load ratio. Therefore, the aim of this study is to investigate the optimal design and operation of a syngas-fuelled SOFC micro-CHP system for small households located in five different climate zones in China. The ability of the micro-CHP to cover the heat and electricity demand of a 70m2...... demand. Numerical simulations are conducted in Matlab environment. System design trade-offs are discussed to determine the optimal match between the energy demand of the household for different climates across China and the energy supply of the micro-CHP during the whole year. Moreover, criteria...

  18. Materials Properties Database for Selection of High-Temperature Alloys and Concepts of Alloy Design for SOFC Applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Z Gary; Paxton, Dean M.; Weil, K. Scott; Stevenson, Jeffry W.; Singh, Prabhakar

    2002-11-24

    To serve as an interconnect / gas separator in an SOFC stack, an alloy should demonstrate the ability to provide (i) bulk and surface stability against oxidation and corrosion during prolonged exposure to the fuel cell environment, (ii) thermal expansion compatibility with the other stack components, (iii) chemical compatibility with adjacent stack components, (iv) high electrical conductivity of the surface reaction products, (v) mechanical reliability and durability at cell exposure conditions, (vii) good manufacturability, processability and fabricability, and (viii) cost effectiveness. As the first step of this approach, a composition and property database was compiled for high temperature alloys in order to assist in determining which alloys offer the most promise for SOFC interconnect applications in terms of oxidation and corrosion resistance. The high temperature alloys of interest included Ni-, Fe-, Co-base superal

  19. Fundamental Investigations and Rational Design of Durable High-Performance SOFC Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu [Georgia Inst. of Technology, Atlanta, GA (United States); Ding, Dong [Georgia Inst. of Technology, Atlanta, GA (United States); Wei, Tao [Georgia Inst. of Technology, Atlanta, GA (United States); Liu, Meilin [Georgia Inst. of Technology, Atlanta, GA (United States)

    2016-03-31

    The main objective of this project is to unravel the degradation mechanism of LSCF cathodes under realistic operating conditions with different types of contaminants, aiming towards the rational design of cathodes with high-performance and enhanced durability by combining a porous backbone (such as LSCF) with a thin catalyst coating. The mechanistic understanding will help us to optimize the composition and morphology of the catalyst layer and microstructure of the LSCF backbone for better performance and durability. More specifically, the technical objectives include: (1) to unravel the degradation mechanism of LSCF cathodes under realistic operating conditions with different types of contaminants using in situ and ex situ measurements performed on specially-designed cathodes; (2) to examine the microstructural and compositional evolution of LSCF cathodes as well as the cathode/electrolyte interfaces under realistic operating conditions; (3) to correlate the fuel cell performance instability and degradation with the microstructural and morphological evolution and surface chemistry change of the cathode under realistic operating conditions; (4) to explore new catalyst materials and electrode structures to enhance the stability of the LSCF cathode under realistic operating conditions; and (5) to validate the long term stability of the modified LSCF cathode in commercially available cells under realistic operating conditions. We have systematically evaluated LSCF cathodes in symmetrical cells and anode supported cells under realistic conditions with different types of contaminants such as humidity, CO2, and Cr. Electrochemical models for the design of test cells and understanding of mechanisms have been developed for the exploration of fundamental properties of electrode materials. It is demonstrated that the activity and stability of LSCF cathodes can be degraded by the introduction of contaminants. The microstructural and compositional evolution of LSCF

  20. Final Report, Validation of Novel Planar Cell Design for MW-Scale SOFC Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Swartz, Dr Scott L.; Thrun, Dr Lora B.; Arkenberg, Mr Gene B.; Chenault, Ms Kellie M.

    2012-01-03

    This report describes the work completed by NexTech Materials, Ltd. during a three-year project to validate an electrolyte-supported planar solid oxide fuel cell design, termed the FlexCell, for coal-based, megawatt-scale power generation systems. This project was focused on the fabrication and testing of electrolyte-supported FlexCells with yttria-stabilized zirconia (YSZ) as the electrolyte material. YSZ based FlexCells were made with sizes ranging from 100 to 500 cm2. Single-cell testing was performed to confirm high electrochemical performance, both with diluted hydrogen and simulated coal gas as fuels. Finite element analysis modeling was performed at The Ohio State University was performed to establish FlexCell architectures with optimum mechanical robustness. A manufacturing cost analysis was completed, which confirmed that manufacturing costs of less than $50/kW are achievable at high volumes (500 MW/year).

  1. Validation of Novel Planar Cell Design for MW-Scale SOFC Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Scott Swartz; Lora Thrun; Gene Arkenberg; Kellie Chenault

    2011-09-30

    This report describes the work completed by NexTech Materials, Ltd. during a three-year project to validate an electrolyte-supported planar solid oxide fuel cell design, termed the FlexCell, for coal-based, megawatt-scale power generation systems. This project was focused on the fabrication and testing of electrolyte-supported FlexCells with yttria-stabilized zirconia (YSZ) as the electrolyte material. YSZ based FlexCells were made with sizes ranging from 100 to 500 cm{sup 2}. Single-cell testing was performed to confirm high electrochemical performance, both with diluted hydrogen and simulated coal gas as fuels. Finite element analysis modeling was performed at The Ohio State University was performed to establish FlexCell architectures with optimum mechanical robustness. A manufacturing cost analysis was completed, which confirmed that manufacturing costs of less than $50/kW are achievable at high volumes (500 MW/year). DISCLAIMER

  2. Influence of Electrode Design and Contacting Layers on Performance of Electrolyte Supported SOFC/SOEC Single Cells

    OpenAIRE

    Mihails Kusnezoff; Nikolai Trofimenko; Martin Müller; Alexander Michaelis

    2016-01-01

    The solid oxide cell is a basis for highly efficient and reversible electrochemical energy conversion. A single cell based on a planar electrolyte substrate as support (ESC) is often utilized for SOFC/SOEC stack manufacturing and fulfills necessary requirements for application in small, medium and large scale fuel cell and electrolysis systems. Thickness of the electrolyte substrate, and its ionic conductivity limits the power density of the ESC. To improve the performance of this cell type i...

  3. Electrode design for direct-methane micro-tubular solid oxide fuel cell (MT-SOFC)

    Science.gov (United States)

    Rabuni, Mohamad Fairus; Li, Tao; Punmeechao, Puvich; Li, Kang

    2018-04-01

    Herein, a micro-structured electrode design has been developed via a modified phase-inversion method. A thin electrolyte integrated with a highly porous anode scaffold has been fabricated in a single-step process and developed into a complete fuel cell for direct methane (CH4) utilisation. A continuous and well-dispersed layer of copper-ceria (Cu-CeO2) was incorporated inside the micro-channels of the anode scaffold. A complete cell was investigated for direct CH4 utilisation. The well-organised micro-channels and nano-structured Cu-CeO2 anode contributed to an increase in electrochemical reaction sites that promoted charge-transfer as well as facilitating gaseous fuel distribution, resulting in outstanding performances. Excellent electrochemical performances have been achieved in both hydrogen (H2) and CH4 operation. The power density of 0.16 Wcm-2 at 750 °C with dry CH4 as fuel is one of the highest ever reported values for similar anode materials.

  4. Influence of Electrode Design and Contacting Layers on Performance of Electrolyte Supported SOFC/SOEC Single Cells

    Directory of Open Access Journals (Sweden)

    Mihails Kusnezoff

    2016-11-01

    Full Text Available The solid oxide cell is a basis for highly efficient and reversible electrochemical energy conversion. A single cell based on a planar electrolyte substrate as support (ESC is often utilized for SOFC/SOEC stack manufacturing and fulfills necessary requirements for application in small, medium and large scale fuel cell and electrolysis systems. Thickness of the electrolyte substrate, and its ionic conductivity limits the power density of the ESC. To improve the performance of this cell type in SOFC/SOEC mode, alternative fuel electrodes, on the basis of Ni/CGO as well as electrolytes with reduced thickness, have been applied. Furthermore, different interlayers on the air side have been tested to avoid the electrode delamination and to reduce the cell degradation in electrolysis mode. Finally, the influence of the contacting layer on cell performance, especially for cells with an ultrathin electrolyte and thin electrode layers, has been investigated. It has been found that Ni/CGO outperform traditional Ni/8YSZ electrodes and the introduction of a ScSZ interlayer substantially reduces the degradation rate of ESC in electrolysis mode. Furthermore, it was demonstrated that, for thin electrodes, the application of contacting layers with good conductivity and adhesion to current collectors improves performance significantly.

  5. Influence of Electrode Design and Contacting Layers on Performance of Electrolyte Supported SOFC/SOEC Single Cells.

    Science.gov (United States)

    Kusnezoff, Mihails; Trofimenko, Nikolai; Müller, Martin; Michaelis, Alexander

    2016-11-08

    The solid oxide cell is a basis for highly efficient and reversible electrochemical energy conversion. A single cell based on a planar electrolyte substrate as support (ESC) is often utilized for SOFC/SOEC stack manufacturing and fulfills necessary requirements for application in small, medium and large scale fuel cell and electrolysis systems. Thickness of the electrolyte substrate, and its ionic conductivity limits the power density of the ESC. To improve the performance of this cell type in SOFC/SOEC mode, alternative fuel electrodes, on the basis of Ni/CGO as well as electrolytes with reduced thickness, have been applied. Furthermore, different interlayers on the air side have been tested to avoid the electrode delamination and to reduce the cell degradation in electrolysis mode. Finally, the influence of the contacting layer on cell performance, especially for cells with an ultrathin electrolyte and thin electrode layers, has been investigated. It has been found that Ni/CGO outperform traditional Ni/8YSZ electrodes and the introduction of a ScSZ interlayer substantially reduces the degradation rate of ESC in electrolysis mode. Furthermore, it was demonstrated that, for thin electrodes, the application of contacting layers with good conductivity and adhesion to current collectors improves performance significantly.

  6. Optimal design and operation of a syngas-fuelled SOFC micro CHP system for residential applications in different climate zones in China

    DEFF Research Database (Denmark)

    Yang, Wenyuan; Zhao, Yingru; Liso, Vincenzo

    2014-01-01

    under difference climate conditions to ensure that it is well matched with the local heat-to-power ratio. The aim of this study is to investigate the optimal design and operation of a syngas-fuelled SOFC micro-CHP system for small households located in five different climate zones in China. The ability...... of the micro-CHP to cover the heat and electricity demand of a 70 m2 single-family apartment with an average number of occupants of 3 is evaluated. A detailed model of the micro-CHP unit coupled with a hot water storage tank and an auxiliary boiler is developed. System design trade-offs are discussed...

  7. Computer experimental analysis of the CHP performance of a 100 kW e SOFC Field Unit by a factorial design

    Science.gov (United States)

    Calì, M.; Santarelli, M. G. L.; Leone, P.

    Gas Turbine Technologies (GTT) and Politecnico di Torino, both located in Torino (Italy), have been involved in the design and installation of a SOFC laboratory in order to analyse the operation, in cogenerative configuration, of the CHP 100 kW e SOFC Field Unit, built by Siemens-Westinghouse Power Corporation (SWPC), which is at present (May 2005) starting its operation and which will supply electric and thermal power to the GTT factory. In order to take the better advantage from the analysis of the on-site operation, and especially to correctly design the scheduled experimental tests on the system, we developed a mathematical model and run a simulated experimental campaign, applying a rigorous statistical approach to the analysis of the results. The aim of this work is the computer experimental analysis, through a statistical methodology (2 k factorial experiments), of the CHP 100 performance. First, the mathematical model has been calibrated with the results acquired during the first CHP100 demonstration at EDB/ELSAM in Westerwoort. After, the simulated tests have been performed in the form of computer experimental session, and the measurement uncertainties have been simulated with perturbation imposed to the model independent variables. The statistical methodology used for the computer experimental analysis is the factorial design (Yates' Technique): using the ANOVA technique the effect of the main independent variables (air utilization factor U ox, fuel utilization factor U F, internal fuel and air preheating and anodic recycling flow rate) has been investigated in a rigorous manner. Analysis accounts for the effects of parameters on stack electric power, thermal recovered power, single cell voltage, cell operative temperature, consumed fuel flow and steam to carbon ratio. Each main effect and interaction effect of parameters is shown with particular attention on generated electric power and stack heat recovered.

  8. Multi-objective design and operation of Solid Oxide Fuel Cell (SOFC) Triple Combined-cycle Power Generation systems: Integrating energy efficiency and operational safety

    International Nuclear Information System (INIS)

    Sharifzadeh, Mahdi; Meghdari, Mojtaba; Rashtchian, Davood

    2017-01-01

    Highlights: • Integrating Solid Oxide Fuel Cells with thermal power plants enhance overall energy efficiency. • However, the high degree of process integration in hybrid power plants limits the operating window. • Multi-objective optimization was applied for integrated design and operation. • The Pareto optimal solutions demonstrated strong trade-off between energy efficiency and operational safety. - Abstract: Energy efficiency is one of the main pathways for energy security and environmental protection. In fact, the International Energy Agency asserts that without energy efficiency, 70% of targeted emission reductions are not achievable. Despite this clarity, enhancing the energy efficiency introduce significant challenge toward process operation. The reason is that the methods applied for energy-saving pose the process operation at the intersection of safety constraints. The present research aims at uncovering the trade-off between safe operation and energy efficiency; an optimization framework is developed that ensures process safety and simultaneously optimizes energy-efficiency, quantified in economic terms. The developed optimization framework is demonstrated for a solid oxide fuel cell (SOFC) power generation system. The significance of this industrial application is that SOFC power plants apply a highly degree of process integration resulting in very narrow operating windows. However, they are subject to significant uncertainties in power demand. The results demonstrate a strong trade-off between the competing objectives. It was observed that highly energy-efficient designs feature a very narrow operating window and limited flexibility. For instance, expanding the safe operating window by 100% will incur almost 47% more annualized costs. Establishing such a trade-off is essential for realizing energy-saving.

  9. Towards Multi Fuel SOFC Plant

    DEFF Research Database (Denmark)

    Rokni, Masoud; Clausen, Lasse Røngaard; Bang-Møller, Christian

    2011-01-01

    Complete Solid Oxide Fuel Cell (SOFC) plants fed by several different fuels are suggested and analyzed. The plants sizes are about 10 kW which is suitable for single family house with needs for both electricity and heat. Alternative fuels such as, methanol, DME (Di-Methyl Ether) and ethanol...... are also considered and the results will be compared with the base plant fed by Natural Gas (NG). A single plant design will be suggested that can be fed with methanol, DME and ethanol whenever these fuels are available. It will be shown that the plant fed by ethanol will have slightly higher electrical...

  10. SOFC interface studies

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Bay, Lasse; West, Keld

    performance and inductive hysteresis phenomena often observed in SOFC kinetic studies (\\ref{TJ01}). Fig.\\,\\ref{cath_laser} shows the YSZ surface developed below a Pt point electrode polarised at -0.10\\, V at $1000^\\circ$C for a period of 85 days. The structural as well as the compositional changes...

  11. Status of the TMI SOFC system

    Energy Technology Data Exchange (ETDEWEB)

    Ruhl, R.C.; Petrik, M.A.; Cable, T.L. [Technology Management, Inc., Cleveland, OH (United States)

    1996-12-31

    TMI has completed preliminary engineering designs for complete 20kW SOFC systems modules for stationary distributed generation applications using pipeline natural gas [sponsored by Rochester Gas and Electric (Rochester, New York) and EPRI (Palo Alto, California)]. Subsystem concepts are currently being tested.

  12. Status of SOFC development at Siemens

    Energy Technology Data Exchange (ETDEWEB)

    Drenckhahn, W.; Blum, L.; Greiner, H. [Siemens AG, Erlangen (Germany)

    1996-12-31

    The Siemens SOFC development programme reached an important milestone in June 1995. A stack operating with hydrogen and oxygen produced a peak power of 10.7 kW at a current density of 0.7 A/cm{sup 2} and was running for more than 1400 hours. The SOFC configuration is based on a flat metal separator plate using the multiple cell array design. Improved PENs, functional layer and joining technique were implemented. Based on this concept, a 100 kW plant was designed The SOFC development at Siemens has been started in 1990 after a two years preparation phase. The first period with the goal of the demonstration of a 1 kW SOFC stack operation ended in 1993. This important milestone was finally reached in the begin of 1994. The second project phase with the final milestone of a 20 kW module operation will terminate at the end of 1996. This result will form a basis for the next phase in which a 50 to 100 kW pilot plant will be built and tested.

  13. Facts and figures, an International Energy Agency SOFC task report

    Energy Technology Data Exchange (ETDEWEB)

    Bossel, U G; Dubal, L [ed.

    1992-04-15

    The report covers the following themes: SOFC chemistry, properties of SOFC gases and materials, electrochemistry, electric current flow in SOFC elements, SOFC configurations, mass flow phenomena and linearized SOFC performance analysis. figs., tabs., 27 refs.

  14. Power generation efficiency of an SOFC-PEFC combined system with time shift utilization of SOFC exhaust heat

    Energy Technology Data Exchange (ETDEWEB)

    Obara, Shin' ya [Power Engineering Lab., Department of Electrical and Electronic Engineering, Kitami Institute of Technology, 165 Kouen-cho, Kitami, Hokkaido 0908507 (Japan)

    2010-01-15

    A microgrid, with little environmental impact, is developed by introducing a combined SOFC (solid oxide fuel cell) and PEFC (proton exchange membrane fuel cell) system. Although the SOFC requires a higher operation temperature compared to the PEFC, the power generation efficiency of the SOFC is higher. However, if high temperature exhaust heat may be used effectively, a system with higher total power generation efficiency can be built. Therefore, this paper investigates the operation of a SOFC-PEFC combined system, with time shift operation of reformed gas, into a microgrid with 30 houses in Sapporo, Japan. The SOFC is designed to correspond to base load operation, and the exhaust heat of the SOFC is used for production of reformed gas. This reformed gas is used for the production of electricity for the PEFC, corresponding to fluctuation load of the next day. Accordingly, the reformed gas is used with a time shift operation. In this paper, the relation between operation method, power generation efficiency, and amount of heat storage of the SOFC-PEFC combined system to the difference in power load pattern was investigated. The average power generation efficiency of the system can be maintained at nearly 48% on a representative day in February (winter season) and August (summer season). (author)

  15. Progress in understanding SOFC electrodes

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Hansen, Karin Vels; Jørgensen, M.J.

    2002-01-01

    The literature of SOFC electrode kinetics and mechanisms is full of contradicting details in case of both the SOFC anode and cathode processes. Only weak patterns may be identified. One interpretation is that each of the reported data sets reflects a laboratory specific nature of each of the elec...

  16. Gradient composite metal-ceramic foam as supportive component for planar SOFCs and MIEC membranes

    International Nuclear Information System (INIS)

    Smorygo, Oleg; Mikutski, Vitali; Marukovich, Alexander; Sadykov, Vladislav; Usoltsev, Vladimir; Mezentseva, Natalia; Borodinecs, Anatolijs; Bobrenok, Oleg

    2011-01-01

    A novel approach to the design of planar gradient porous supports for the thin-film SOFCs and MIEC membranes is described. The support's thermal expansion is controlled by the creation of a two-component composite metal-ceramic foam structure. Thin MIEC membranes and SOFCs were prepared on the composite supports by the layerwise deposition of composite functional layers including complex fluorites and perovskites. Lab-scale studies demonstrated promising performance of both MIEC membrane and SOFC.

  17. Gradient composite metal-ceramic foam as supportive component for planar SOFCs and MIEC membranes

    Science.gov (United States)

    Smorygo, Oleg; Mikutski, Vitali; Marukovich, Alexander; Sadykov, Vladislav; Usoltsev, Vladimir; Mezentseva, Natalia; Borodinecs, Anatolijs; Bobrenok, Oleg

    2011-06-01

    A novel approach to the design of planar gradient porous supports for the thin-film SOFCs and MIEC membranes is described. The support's thermal expansion is controlled by the creation of a two-component composite metal-ceramic foam structure. Thin MIEC membranes and SOFCs were prepared on the composite supports by the layerwise deposition of composite functional layers including complex fluorites and perovskites. Lab-scale studies demonstrated promising performance of both MIEC membrane and SOFC.

  18. SOFC Systems with Improved Reliability and Endurance

    Energy Technology Data Exchange (ETDEWEB)

    Ghezel-Ayagh, Hossein [Fuelcell Energy, Incorporated, Danbury, CT (United States)

    2015-12-31

    The overall goal of this U.S. Department of Energy (DOE) sponsored project was the development of Solid Oxide Fuel Cell (SOFC) technology suitable for ultra-efficient central power generation systems utilizing coal and natural gas fuels and featuring greater than 90% carbon dioxide capture. The specific technical objective of this project was to demonstrate, via analyses and testing, progress towards adequate stack life (≥ 4 years) and stack performance stability (degradation rate ≤ 0.2% per 1000 hours) in a low-cost SOFC stack design. This final technical report summarizes the progress made during the project period of 27 months. Significant progress was made in the areas of cell and stack technology development, stack module development, sub-scale module tests, and Proof-of-Concept Module unit design, fabrication and testing. The work focused on cell and stack materials and designs, balance-of-plant improvements, and performance evaluation covering operating conditions and fuel compositions anticipated for commercially-deployed systems. In support of performance evaluation under commercial conditions, this work included the design, fabrication, siting, commissioning, and operation of a ≥ 50 kWe proof-of-concept module (PCM) power plant, based upon SOFC cell and stack technology developed to date by FuelCell Energy, Inc. (FCE) under the Office of Fossil Energy’s Solid Oxide Fuel Cells program. The PCM system was operated for at least 1000 hours on natural gas fuel at FCE’s facility. The factory cost of the SOFC stack was estimated to be at or below the DOE’s high-volume production cost target (2011 $).

  19. Thermodynamic model and parametric analysis of a tubular SOFC module

    Science.gov (United States)

    Campanari, Stefano

    Solid oxide fuel cells (SOFCs) have been considered in the last years as one of the most promising technologies for very high-efficiency electric energy generation from natural gas, both with simple fuel cell plants and with integrated gas turbine-fuel cell systems. Among the SOFC technologies, tubular SOFC stacks with internal reforming have emerged as one of the most mature technology, with a serious potential for a future commercialization. In this paper, a thermodynamic model of a tubular SOFC stack, with natural gas feeding, internal reforming of hydrocarbons and internal air preheating is proposed. In the first section of the paper, the model is discussed in detail, analyzing its calculating equations and tracing its logical steps; the model is then calibrated on the available data for a recently demonstrated tubular SOFC prototype plant. In the second section of the paper, it is carried out a detailed parametric analysis of the stack working conditions, as a function of the main operating parameters. The discussion of the results of the thermodynamic and parametric analysis yields interesting considerations about partial load SOFC operation and load regulation, and about system design and integration with gas turbine cycles.

  20. Status of SOFCo SOFC technology development

    Energy Technology Data Exchange (ETDEWEB)

    Privette, R.; Perna, M.A.; Kneidel, K. [SOFCo, Alliance, OH (United States)] [and others

    1996-12-31

    SOFCo, a Babcock & Wilcox/Ceramatec Research & Development Limited Partnership, is a collaborative research and development venture to develop technologies related to planar, solid-oxide fuel cells (SOFCs). SOFCo has successfully demonstrated a kW-class, solid-oxide fuel cell module operating on pipeline natural gas. The SOFC system design integrates the air preheater and the fuel processor with the fuel cell stacks into a compact test unit; this is the platform for multi-kW modules. The cells, made of tape-cast zirconia electrolyte and conventional electrode materials, exhibit excel lent stability in single-cell tests approaching 40,000 hours of operation. Stack tests using 10-cm and 15-cm cells with ceramic interconnects also show good performance and stability in tests for many thousands of hours.

  1. SOFC Operation with Real Biogas

    DEFF Research Database (Denmark)

    Hagen, Anke; Winiwarter, Anna; Langnickel, Hendrik

    2017-01-01

    Biogas is a valuable energy source and will be available in future in systems relying on renewables. It is an attractive fuel for solid oxide fuel cells (SOFC), which are able to utilize the carbon contained in the biogas and which produce electricity with high efficiency. In the current paper......, state‐of‐the‐art SOFCs were studied regarding performance and durability in relation to biogas as fuel and considering important contaminants, specifically sulfur. First, the catalytic behavior in relevant synthetic biogas mixtures was studied and the potential of dry reforming was demonstrated....... Successful long term operation of an SOFC under both, conditions of steam and dry reforming, i.e., addition of steam or CO2 to avoid carbon formation was shown. For the steam reforming case a remarkable period of 3,500 h, hereof 3,000 h in the presence of H2S was achieved. Finally, a real biogas from...

  2. In-Operando Raman Characterization of Carbon Deposition on SOFC Anodes

    KAUST Repository

    Maher, R. C.

    2013-10-06

    Carbon formation within nickel-based solid oxide fuel cell (SOFC) anodes exposed to carbonaceous fuels typically leads to reduced operational lifetimes and performance, and can eventually lead to catastrophic failure through cracking and delamination. In-situ Raman spectroscopy has been shown to be a powerful characterization tool for the investigation of the dynamics of physical processes occurring within operational SOFCs in real time. Here we investigate the dynamics of carbon formation on a variety of nickel-based SOFC anodes as a function of temperature, fuel and electrical loading using Raman spectroscopy. We show that the rate of carbon formation throughout the SOFC anode can be significantly reduced through a careful consideration of the SOFC anode material, design and operational conditions. © The Electrochemical Society.

  3. In-Operando Raman Characterization of Carbon Deposition on SOFC Anodes

    KAUST Repository

    Maher, R. C.; Duboviks, V.; Offer, G.; Cohen, L. F.; Brandon, N. P.

    2013-01-01

    Carbon formation within nickel-based solid oxide fuel cell (SOFC) anodes exposed to carbonaceous fuels typically leads to reduced operational lifetimes and performance, and can eventually lead to catastrophic failure through cracking and delamination. In-situ Raman spectroscopy has been shown to be a powerful characterization tool for the investigation of the dynamics of physical processes occurring within operational SOFCs in real time. Here we investigate the dynamics of carbon formation on a variety of nickel-based SOFC anodes as a function of temperature, fuel and electrical loading using Raman spectroscopy. We show that the rate of carbon formation throughout the SOFC anode can be significantly reduced through a careful consideration of the SOFC anode material, design and operational conditions. © The Electrochemical Society.

  4. Modeling work of a small scale gasifier/SOFC CHP system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, M.; Aravind, P.V.; Qu, Z.; Woudstra, N.; Verkooijen, A.H.M. [Delft University of Technology (Netherlands). Dept. of Mechanical Engineering], Emails: ming.liu@tudelft.nl, p.v.aravind@tudelft.nl, z.qu@tudelft.nl, n.woudstra@tudelft.nl, a. h. m. verkooijen@tudelft.nl; Cobas, V.R.M. [Federal University of Itajuba (UNIFEI), Pinheirinhos, MG (Brazil). Dept. of Mechanical Engineering], E-mail: vlad@unifei.edu.br

    2009-07-01

    For a highly efficient biomass gasification/Solid Oxide Fuel Cell (SOFC) Combined Heat and Power (CHP) generation system, the gasifier, the accompanying gas cleaning technologies and the CHP unit must be carefully designed as an integrated unit. This paper describes such a system involving a two-stage fixed-bed down draft gasifier, a SOFC CHP unit and a gas cleaning system. A gas cleaning system with both low temperature and high temperature sections is proposed for coupling the gasifier and the SOFC. Thermodynamic modeling was carried out for the gasifier/SOFC system with the proposed gas cleaning system. The net AC electrical efficiency of this system is around 30% and the overall system efficiency is around 60%. This paper also describes various exergy losses in the system and the future plans for integrated gasifier-GCU-SOFC experiments from which the results will be used to validate the modeling results of this system. (author)

  5. Perovskites synthesis to SOFC anodes

    International Nuclear Information System (INIS)

    Wendler, L.P.; Chinelatto, A.L.; Chinelatto, A.S.A.; Ramos, K.

    2012-01-01

    Perovskite structure materials containing lanthanum have been widely applied as solid oxide fuel cells (SOFCs) electrodes, due to its electrical properties. Was investigated the obtain of the perovskite structure LaCr 0,5 Ni 0,5 O 3 , by Pechini method, and its suitability as SOFC anode. The choice of this composition was based on the stability provided by chromium and the catalytic properties of nickel. After preparing the resins, the samples were calcined at 300 deg C, 600 deg C, 700 deg C and 850 deg C. The resulting powders were characterized by X-ray diffraction to determine the existing phases. Furthermore, were performed other analysis, like X-ray fluorescence, He pycnometry, specific surface area by BET isotherm and scanning electronic microscopy (author)

  6. Fundamental researches of SOFC in Russia

    Energy Technology Data Exchange (ETDEWEB)

    Demin, A.K.; Neuimin, A.D.; Perfiliev, M.V. [Institute of High Temperatures Electrochemistry, Ekaterinburg (Russian Federation)

    1996-04-01

    The main results of research on ZrO{sub 2}-based solid electrolytes, electrodes and interconnects are reviewed. The mathematical models of the processes in SOFC are considered. Two types of SOFC stacks composed of tubular and block cells, as well the results of their tests are described.

  7. Heat and mass transfer analysis intermediate temperature solid oxide fuel cells (IT-SOFC)

    International Nuclear Information System (INIS)

    Timurkutluk, B.; Mat, M. M.; Kaplan, Y.

    2007-01-01

    Solid oxide fuel cells (SOFCs) have been considered as next generation energy conversion system due to their high efficiency, clean and quite operation with fuel flexibility. To date, yittria stabilized zirconia (YSZ) electrolytes have been mainly used for SOFC applications at high temperatures around 1000 degree C because of their high ionic conductivity, chemical stability and good mechanical properties. However, such a high temperature is undesirable for fuel cell operations in the viewpoint of stability. Moreover, high operation temperature necessitates high cost interconnect and seal materials. Thus, the reduction in the operation temperature of SOFCs is one of the key issues in the aspects of the cost reduction and the long term operation without degradation as well as commercialization of the SOFC systems. With the reducing temperature, not only low cost stainless steels and glass materials can be used as interconnect and sealing materials respectively but the manufacturing technology will also extend. Therefore, the design of complex geometrical SOFC component will also be possible. One way to reduce the operation temperature of SOFC is use of an alternative electrolyte material to YSZ showing acceptable properties at intermediate temperatures (600-800 degree C). As being one of IT-SOFC electrolyte materials, gadolinium doped ceria (GDC) has been taken great deals. In this study, a mathematical model for mass and heat transfer for a single cell GDC electrolyte SOFC system was developed and numerical solutions were evaluated. In order to verify the mathematical model, set of experiments were performed by taking species from four different samples randomly and five various temperature measurements. The numerical results reasonably agree with experimental data

  8. Possible Future SOFC - ST Based Power Plants

    OpenAIRE

    Rokni, Masoud; Scappin, Fabio

    2009-01-01

    Hybrid systems consisting Solid Oxide Fuel Cell (SOFC) on the top of a Steam Turbine (ST) are investigated. The plants are fired by natural gas. A desulfurization reactor removes the sulfur content in the NG while a pre-reformer break down the heavier hydrocarbons. The pre-treated fuel enters then into the anode side of the SOFC. The gases from the SOFC stacks enter into a burner to burn the rest of the fuel. The off-gases now enter into a heat recovery steam generator to produce steam for a ...

  9. Development of Residential SOFC Cogeneration System

    Science.gov (United States)

    Ono, Takashi; Miyachi, Itaru; Suzuki, Minoru; Higaki, Katsuki

    2011-06-01

    Since 2001 Kyocera has been developing 1kW class Solid Oxide Fuel Cell (SOFC) for power generation system. We have developed a cell, stack, module and system. Since 2004, Kyocera and Osaka Gas Co., Ltd. have been developed SOFC residential co-generation system. From 2007, we took part in the "Demonstrative Research on Solid Oxide Fuel Cells" Project conducted by New Energy Foundation (NEF). Total 57 units of 0.7kW class SOFC cogeneration systems had been installed at residential houses. In spite of residential small power demand, the actual electric efficiency was about 40%(netAC,LHV), and high CO2 reduction performance was achieved by these systems. Hereafter, new joint development, Osaka Gas, Toyota Motors, Kyocera and Aisin Seiki, aims early commercialization of residential SOFC CHP system.

  10. Development of Residential SOFC Cogeneration System

    International Nuclear Information System (INIS)

    Ono, Takashi; Miyachi, Itaru; Suzuki, Minoru; Higaki, Katsuki

    2011-01-01

    Since 2001 Kyocera has been developing 1kW class Solid Oxide Fuel Cell (SOFC) for power generation system. We have developed a cell, stack, module and system. Since 2004, Kyocera and Osaka Gas Co., Ltd. have been developed SOFC residential co-generation system. From 2007, we took part in the 'Demonstrative Research on Solid Oxide Fuel Cells' Project conducted by New Energy Foundation (NEF). Total 57 units of 0.7kW class SOFC cogeneration systems had been installed at residential houses. In spite of residential small power demand, the actual electric efficiency was about 40%(netAC,LHV), and high CO2 reduction performance was achieved by these systems. Hereafter, new joint development, Osaka Gas, Toyota Motors, Kyocera and Aisin Seiki, aims early commercialization of residential SOFC CHP system.

  11. LG Solid Oxide Fuel Cell (SOFC) Model Development

    Energy Technology Data Exchange (ETDEWEB)

    Haberman, Ben [LG Fuel Cell Systems Inc., North Canton, OH (United States); Martinez-Baca, Carlos [LG Fuel Cell Systems Inc., North Canton, OH (United States); Rush, Greg [LG Fuel Cell Systems Inc., North Canton, OH (United States)

    2013-05-31

    This report presents a summary of the work performed by LG Fuel Cell Systems Inc. during the project LG Solid Oxide Fuel Cell (SOFC) Model Development (DOE Award Number: DE-FE0000773) which commenced on October 1, 2009 and was completed on March 31, 2013. The aim of this project is for LG Fuel Cell Systems Inc. (formerly known as Rolls-Royce Fuel Cell Systems (US) Inc.) (LGFCS) to develop a multi-physics solid oxide fuel cell (SOFC) computer code (MPC) for performance calculations of the LGFCS fuel cell structure to support fuel cell product design and development. A summary of the initial stages of the project is provided which describes the MPC requirements that were developed and the selection of a candidate code, STAR-CCM+ (CD-adapco). This is followed by a detailed description of the subsequent work program including code enhancement and model verification and validation activities. Details of the code enhancements that were implemented to facilitate MPC SOFC simulations are provided along with a description of the models that were built using the MPC and validated against experimental data. The modeling work described in this report represents a level of calculation detail that has not been previously available within LGFCS.

  12. Development of a solid oxide fuel cell (SOFC) automotive auxiliary power unit (APU) fueled by gasoline

    International Nuclear Information System (INIS)

    DeMinco, C.; Mukerjee, S.; Grieve, J.; Faville, M.; Noetzel, J.; Perry, M.; Horvath, A.; Prediger, D.; Pastula, M.; Boersma, R.; Ghosh, D.

    2000-01-01

    This paper describes the design and the development progress of a 3 to 5 auxiliary power unit (APU) based on a gasoline fueled solid oxide fuel cell (SOFC). This fuel cell was supplied reformate gas (reactant) by a partial oxidation (POx) catalytic reformer utilizing liquid gasoline and designed by Delphi Automotive Systems. This reformate gas consists mainly of hydrogen, carbon monoxide and nitrogen and was fed directly in to the SOFC stack without any additional fuel reformer processing. The SOFC stack was developed by Global Thermoelectric and operates around 700 o C. This automotive APU produces power to support future 42 volt vehicle electrical architectures and loads. The balance of the APU, designed by Delphi Automotive Systems, employs a packaging and insulation design to facilitate installation and operation on-board automobiles. (author)

  13. The integrated project SOFC600 development of low-temperature SOFC

    DEFF Research Database (Denmark)

    Rietveld, B.; Van Berkel, F.; Zhang-Steenwinkel, Y.

    2009-01-01

    The Integrated Project SOFC600 unites 21 partners jointly working on the research and development of SOFC stack components for operation at 600oC. The project is funded by the European Commission within the 6th Framework Programme. Low-temperature operation is considered essential for achieving c...

  14. Pressurisation of IP-SOFC technology for second generation hybrid application

    Energy Technology Data Exchange (ETDEWEB)

    Jones, L.

    2005-07-01

    The Integrated Planar Solid Oxide Fuel Cell (IP-SOFC) technology developed by Rolls-Royce plc is a hybrid fuel cell technology considered highly suitable for the distributed power generation market. This report presents the results of a project to examine the technical viability of the IP-SOFC technology and some of the associated hybrid system component technologies under pressurised conditions and to investigate the validity of the predicted pressurisation phenomena. The work included: identification of critical material specifications, construction processes, control parameters, etc; the design and commissioning of two pressurised IP-SOFC test rigs at Rolls Royce in Derby; testing two multi-bundle strips at high temperature and atmospheric pressure; testing an active IP-SOFC bundle at high temperature and pressure; testing an experimental steam reforming unit at high temperature and pressure; testing a novel low pressure drop, off-gas combustor concept under atmospheric and pressurised conditions; design studies to identify key parameters affecting the successful integration and packaging of the fuel cell stack with certain associated hybrid components; and designing a hybrid system experimental verification rig. Significant progress was made in addressing the development challenges associated with the IP-SOFC of leakage, performance, durability, yield and geometry, the reaction rate of steam reforming and emissions from the off-gas combustor. Recommendations for future work are made.

  15. Analysis and optimization of a tubular SOFC, using nuclear hydrogen as fuel

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Daniel G.; Parra, Lazaro R.G.; Fernandez, Carlos R.G., E-mail: dgr@instec.cu [Instituto Superior de Tecnologias y Ciencias Aplicadas, Habana (Cuba). Dept. de Ingenieria Nuclear; Lira, Carlos A.B.O., E-mail: cabol@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2013-07-01

    One of the main areas of hydrogen uses as an energy carrier is in fuel cells of high standards as solid oxide fuel cells (SOFC). The SOFCs are fuel cells operate at high temperatures making them ideal for use in large power systems, suitable for distributed generation of electricity. Optimization and analysis of these electrochemical devices is an area of great current study. The computational fluid dynamics software (CFD) have unique advantages for analyzing the influence of design parameters on the efficiency of fuel cells. This paper presents a SOFC design cell which employ as fuel hydrogen produced by thermochemical water splitting cycle (I-S). There will be done the optimization of the main parameters thermodynamic and electrochemical cell operating to achieve top performance. Also will be estimate the cell efficiency and a production-consumption hydrogen system. (author)

  16. Analysis and optimization of a tubular SOFC, using nuclear hydrogen as fuel

    International Nuclear Information System (INIS)

    Rodriguez, Daniel G.; Parra, Lazaro R.G.; Fernandez, Carlos R.G.; Lira, Carlos A.B.O.

    2013-01-01

    One of the main areas of hydrogen uses as an energy carrier is in fuel cells of high standards as solid oxide fuel cells (SOFC). The SOFCs are fuel cells operate at high temperatures making them ideal for use in large power systems, suitable for distributed generation of electricity. Optimization and analysis of these electrochemical devices is an area of great current study. The computational fluid dynamics software (CFD) have unique advantages for analyzing the influence of design parameters on the efficiency of fuel cells. This paper presents a SOFC design cell which employ as fuel hydrogen produced by thermochemical water splitting cycle (I-S). There will be done the optimization of the main parameters thermodynamic and electrochemical cell operating to achieve top performance. Also will be estimate the cell efficiency and a production-consumption hydrogen system. (author)

  17. Thermodynamic analysis of SOFC (solid oxide fuel cell)–Stirling hybrid plants using alternative fuels

    International Nuclear Information System (INIS)

    Rokni, Masoud

    2013-01-01

    A novel hybrid power system (∼10 kW) for an average family home is proposed. The system investigated contains a solid oxide fuel cell (SOFC) on top of a Stirling engine. The off-gases produced in the SOFC cycle are fed to a bottoming Stirling engine, at which additional power is generated. Simulations of the proposed system were conducted using different fuels, which should facilitate the use of a variety of fuels depending on availability. Here, the results for natural gas (NG), ammonia, di-methyl ether (DME), methanol and ethanol are presented and analyzed. The system behavior is further investigated by comparing the effects of key factors, such as the utilization factor and the operating conditions under which these fuels are used. Moreover, the effect of using a methanator on the plant efficiency is also studied. The combined system improves the overall electrical efficiency relative to that of a stand-alone Stirling engine or SOFC plant. For the combined SOFC and Stirling configuration, the overall power production was increased by approximately 10% compared to that of a stand-alone SOFC plant. System efficiencies of approximately 60% are achieved, which is remarkable for such small plant sizes. Additionally, heat is also produced to heat the family home when necessary. - Highlights: • Integrating a solid oxide fuel with a Stirling engine • Design of multi-fuel hybrid plants • Plants running on alternative fuels; natural gas, methanol, ethanol, DME and ammonia • Thermodynamic analysis of hybrid SOFC–Stirling engine plants

  18. Development of Osaka gas type planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Iha, M.; Shiratori, A.; Chikagawa, O. [Murata Mfg. Co., Ltd., Shiga (Japan)] [and others

    1996-12-31

    Osaka Gas Co. has been developing a planar type SOFC (OG type SOFC) which has a suitable structure for stacking. Murata Mfg. Co. has begun to develop the OG type SOFC stack through joint program since 1993. Figure 1 shows OG type cell structure. Because each cell is sustained by cell holders acting air manifold, the load of upper cell is not put on the lower cells. Single cell is composed of 3-layered membrane and LaCrO{sub 3} separator. 5 single cells are mounted on the cell holder, connected with Ni felt electrically, and bonded by glassy material sealant. We call the 5-cell stack a unit. Stacking 13 units, we succeeded 870 W generation in 1993. But the power density was low, 0.11 Wcm{sup -2} because of crack in the electrolyte and gas leakage at some cells.

  19. SOFC: Processes and characteristics of ageing behaviour

    International Nuclear Information System (INIS)

    Gerganov, T.; Grigorov, S.; Kozhukharov, S.

    2005-01-01

    The high-temperature solid oxide fuel cell (SOFC) is convenient for the environmental friendly and efficient conversion of chemical into electric energy. During the last decade the development of planar SOFC stacks with metallic interconnects has made considerable progress in both size and power density. The improvement of durability in long-term operation of planar SOFC components is one of the main fields for stationary applications. Ageing of stacks can be caused by various processes, e.g. corrosion of metallic plates, degradation of ceramic parts and chemical interactions on electrodes/electrolyte or interconnect/electrode interface. Namely, these processes are object of the overview in the present work. The most important characteristics of ageing behavior are subjected to analysis and discussion, as well. Moreover a correlation between ageing process and single cell performance will be given

  20. Recent Development of SOFC Metallic Interconnect

    Energy Technology Data Exchange (ETDEWEB)

    Wu JW, Liu XB

    2010-04-01

    Interest in solid oxide fuel cells (SOFC) stems from their higher e±ciencies and lower levels of emitted pollu- tants, compared to traditional power production methods. Interconnects are a critical part in SOFC stacks, which connect cells in series electrically, and also separate air or oxygen at the cathode side from fuel at the anode side. Therefore, the requirements of interconnects are the most demanding, i:e:, to maintain high elec- trical conductivity, good stability in both reducing and oxidizing atmospheres, and close coe±cient of thermal expansion (CTE) match and good compatibility with other SOFC ceramic components. The paper reviewed the interconnect materials, and coatings for metallic interconnect materials.

  1. Ceramic materials for SOFCs: Current status

    Directory of Open Access Journals (Sweden)

    Kozhukharov, V.

    2002-10-01

    Full Text Available It is well known that the main parts of Solid Oxide Fuel Cells (SOFCs are build from ceramic materials. Namely the ceramic materials and composites, used for SOFCs manufacturing, are objects of the overview in the present work. The analysis carried out covers the last current publications in the field discussed. Special attention and examination in details have been done on patents state-of-the-art. After a background and short classification of the ceramic SOFCs materials the attention is focused on cathode, electrolyte, anode, interconnection and sealing materials. Their requirements, structure, thermal stability, composition control and behavior, processing and performance are the object of overview. A correlation has been made between the phase diagrams oxygen incorporation and transport, and SOFC advantages, generally for materials of lanthanum- base perovskite family. In order to analyze the innovative investigations regarding the patent branch of the SOFCs development and application, an object of review was patents from Japan, USA, Germany and European Union. Some examples of the inventions with accent on the ceramic materials are shown. In addition the tendency regarding R & D activities of SOFCs development materials from the leading companies in the world is analyzed. On the base of the most important technological and economical parameters of cell cathode/electrolyte/anode materials an attempt for evaluation and correlation has been made and innovative conceptions are shown.

    Es bien sabido que los componentes principales de las celdas de combustible de óxido sólido (SOFCs estan constituidos por materiales cerámicos. Dichos materiales cerámicos y materiales compuestos que se utilizan en la fabricación de SOFCs son objeto de estudio en el presente trabajo. El análisis llevado a cabo incluye la revisión de las últimas publicaciones en la materia, con una especial atención y examen minucioso sobre las patentes m

  2. Study on dynamic performance of SOFC

    Science.gov (United States)

    Zhan, Haiyang; Liang, Qianchao; Wen, Qiang; Zhu, Runkai

    2017-05-01

    In order to solve the problem of real-time matching of load and fuel cell power, it is urgent to study the dynamic response process of SOFC in the case of load mutation. The mathematical model of SOFC is constructed, and its performance is simulated. The model consider the influence factors such as polarization effect, ohmic loss. It also takes the diffusion effect, thermal effect, energy exchange, mass conservation, momentum conservation. One dimensional dynamic mathematical model of SOFC is constructed by using distributed lumped parameter method. The simulation results show that the I-V characteristic curves are in good agreement with the experimental data, and the accuracy of the model is verified. The voltage response curve, power response curve and the efficiency curve are obtained by this way. It lays a solid foundation for the research of dynamic performance and optimal control in power generation system of high power fuel cell stack.

  3. High Performance Infiltrated Backbones for Cathode-Supported SOFC's

    DEFF Research Database (Denmark)

    Gil, Vanesa; Kammer Hansen, Kent

    2014-01-01

    The concept of using highly ionic conducting backbones with subsequent infiltration of electronically conducting particles has widely been used to develop alternative anode-supported SOFC's. In this work, the idea was to develop infiltrated backbones as an alternative design based on cathode......, microstructural characterization and electrochemical testing are discussed. Data on polarization resistance, Rp, are obtained from impedance spectra recorded on quasi-symmetrical cells (YSZ backbones/YSZ/LSM-YSZ (screen printed)). The backbones are infiltrated with LSM and compared to a standard LSM-YSZ screen...

  4. Development of Long-Term Stable and High-Performing Metal-Supported SOFCs

    DEFF Research Database (Denmark)

    Klemensø, Trine; Nielsen, Jimmi; Blennow Tullmar, Peter

    2011-01-01

    Metal-supported SOFCs are believed to have high potential for commercialization due to lower material costs and higher robustness in fabrication and operation. However, the development of the cell is challenged by the metal properties during fabrication, and the necessary lower operating temperat......Metal-supported SOFCs are believed to have high potential for commercialization due to lower material costs and higher robustness in fabrication and operation. However, the development of the cell is challenged by the metal properties during fabrication, and the necessary lower operating...... temperatures, while retaining both the energy output and the stability. The metal-supported SOFC design developed at Risø DTU has been optimized to an ASR value of 0.62 cm2 at 650 °C, and a steady degradation rate of 1.0% kh-1 demonstrated for 3000 h on a 16 cm2 active cell level. Additional improvement...

  5. Performance and life time test on a 5 kW SOFC system for distributed cogeneration

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, Rosa; De Biase, Sabrina; Ginocchio, Stefano [Edison S.p.A, Via Giorgio La Pira, 2, 10028 Trofarello (Italy); Bedogni, Stefano; Montelatici, Lorenzo [Edison S.p.A, Foro Bonaparte 31, 20121 Milano (Italy)

    2008-06-15

    Edison R and D Centre is committed to test a wide range of commercial and prototypal fuel cell systems. The activities aim to evaluate the available state of the art of these technologies and their maturity for the relevant market. The laboratory is equipped with ad hoc test benches designed to study single cells, stacks and systems. The characterization of commercial and new generation PEMFC, also for high temperatures (160 C), together with the analysis of the behaviour of SOFC represent the core activities of the laboratory. On January 2007 a new 5 kW SOFC system supplied by Acumentrics was installed. The claimed electrical power output is 5 kW and thermal power is 3 kW. The aim of the test is the achievement of technical and economical assessment for future applications of small SOFC plants for distributed cogeneration. Performance and life time test of the system are shown. (author)

  6. Solid oxide fuel cell (SOFC) materials

    CERN Document Server

    Saravanan, R

    2018-01-01

    Developing materials for SOFC applications is one of the key topics in energy research. The book focuses on manganite structured materials, such as doped lanthanum chromites and lanthanum manganites, which have interesting properties: thermal and chemical stability, mixed ionic and electrical conductivity, electrocatalytic activity, magnetocaloric property and colossal magnetoresistance (CMR).

  7. Possible Future SOFC - ST Based Power Plants

    DEFF Research Database (Denmark)

    Rokni, Masoud; Scappin, Fabio

    2009-01-01

    Hybrid systems consisting Solid Oxide Fuel Cell (SOFC) on the top of a Steam Turbine (ST) are investigated. The plants are fired by natural gas. A desulfurization reactor removes the sulfur content in the NG while a pre-reformer break down the heavier hydrocarbons. The pre-treated fuel enters...

  8. Liquid-fueled SOFC power sources for transportation

    Science.gov (United States)

    Myles, K. M.; Doshi, R.; Kumar, R.; Krumpelt, M.

    Traditionally, fuel cells have been developed for space or stationary terrestrial applications. As the first commercial 200-kW systems were being introduced by ONSI and Fuji Electric, the potentially much larger, but also more challenging, application in transportation was beginning to be addressed. As a result, fuel cell-powered buses have been designed and built, and R&D programs for fuel cell-powered passenger cars have been initiated. The engineering challenge of eventually replacing the internal combustion engine in buses, trucks, and passenger cars with fuel cell systems is to achieve much higher power densities and much lower costs than obtainable in systems designed for stationary applications. At present, the leading fuel cell candidate for transportation applications is, without question, the polymer electrolyte fuel cell (PEFC). Offering ambient temperature start-up and the potential for a relatively high power density, the polymer technology has attracted the interest of automotive manufacturers worldwide. But the difficulties of fuel handling for the PEFC have led to a growing interest in exploring the prospects for solid oxide fuel cells (SOFCs) operating on liquid fuels for transportation applications. Solid oxide fuel cells are much more compatible with liquid fuels (methanol or other hydrocarbons) and are potentially capable of power densities high enough for vehicular use. Two SOFC options for such use are discussed in this report.

  9. Investigation of new materials for SOFC applications; Untersuchungen zum Einsatz neuer Werkstoffe fuer SOFC-Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Wackerl, J.

    2007-05-04

    Fuel cells based on solid oxides ('SOFC') are excellent alternative devices for power generation, when they are operated at high temperature, e.g. above 600 C. Having only fixed parts for the power generating part of the device is only one advantage of the fuel cell. Due to their unique design, these devices offer a maximum of efficiency for energy conversion compared to conventional power generating systems, which are mainly based on turbines. One aim of this thesis is the examination of alternative electrolyte and cathode materials for the SOFC applications at reduced temperatures, which means in the temperature range between 600 C and 750 C. For the first main task, several materials from the oxygen ion conducting electrolytes were selected. Different strontium and magnesium doped lanthanum gallate (LSGM) materials with additional transition metal doping were selected and prepared via two different preparation methods. The optimum calcining conditions were determined using thermal analysis methods. The results of the structural analysis of the sintered electrolyte materials were used to select the most suitable electrolyte materials. As a result, LSGM and iron doped LSGM (LSGMF) were the most promising materials. Further investigations were carried out on LSGMF materials with different strontium content. The influence of chemical cation non-stoichiometry on the perovskite material was investigated. Therefore, measurements to gather information about the crystallographic structure, morphology, electrochemistry and electrical conductivity were carried out. For a selected sample, the correlations between single effects, such as the crystallographic structure, and the electrical properties are shown by combining the different analysis methods. It could be shown that both the electrochemistry and the crystallographic structure have a significant influence on the electrical conductivity of the LSGMF materials. The second aim of the thesis was the selection

  10. Continued maturing of SOFC cell production technology and development and demonstration of SOFC stacks. Final report

    Energy Technology Data Exchange (ETDEWEB)

    2008-08-15

    The overall objective of the 6385 project was to develop stack materials, components and stack technology including industrial relevant manufacturing methods for cells components and stacks. Furthermore, the project should include testing and demonstration of the stacks under relevant operating conditions. A production of 6.829 cells, twenty 75-cell stacks and a number of small stacks was achieved. Major improvements were also made in the manufacturing methods and in stack design. Two test and demonstration activities were included in the project. The first test unit was established at H.C. OErsted power plant at the Copenhagen waterfront in order to perform test of SOFC stacks. The unit will be used for tests in other projects. The second demonstration unit is the alpha prototype demonstration in a system running on natural gas in Finland. The alpha prototype demonstration system with 24 TOFC (Topsoe Fuel Cell) stacks was established and started running in October 2007 and operational experience was gained in the period from October 2007 to February 2008. (auther)

  11. Mechanistic Enhancement of SOFC Cathode Durability

    Energy Technology Data Exchange (ETDEWEB)

    Wachsman, Eric [Univ. of Maryland, College Park, MD (United States)

    2016-02-01

    Durability of solid oxide fuel cells (SOFC) under “real world” conditions is an issue for commercial deployment. In particular cathode exposure to moisture, CO2, Cr vapor (from interconnects and BOP), and particulates results in long-term performance degradation issues. Here, we have conducted a multi-faceted fundamental investigation of the effect of these contaminants on cathode performance degradation mechanisms in order to establish cathode composition/structures and operational conditions to enhance cathode durability.

  12. Techno-Economic Feasibility of Highly Efficient Cost-Effective Thermoelectric-SOFC Hybrid Power Generation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Jifeng Zhang; Jean Yamanis

    2007-09-30

    Solid oxide fuel cell (SOFC) systems have the potential to generate exhaust gas streams of high temperature, ranging from 400 to 800 C. These high temperature gas streams can be used for additional power generation with bottoming cycle technologies to achieve higher system power efficiency. One of the potential candidate bottoming cycles is power generation by means of thermoelectric (TE) devices, which have the inherent advantages of low noise, low maintenance and long life. This study was to analyze the feasibility of combining coal gas based SOFC and TE through system performance and cost techno-economic modeling in the context of multi-MW power plants, with 200 kW SOFC-TE module as building blocks. System and component concepts were generated for combining SOFC and TE covering electro-thermo-chemical system integration, power conditioning system (PCS) and component designs. SOFC cost and performance models previously developed at United Technologies Research Center were modified and used in overall system analysis. The TE model was validated and provided by BSST. The optimum system in terms of energy conversion efficiency was found to be a pressurized SOFC-TE, with system efficiency of 65.3% and cost of $390/kW of manufacturing cost. The pressurization ratio was approximately 4 and the assumed ZT of the TE was 2.5. System and component specifications were generated based on the modeling study. The major technology and cost barriers for maturing the system include pressurized SOFC stack using coal gas, the high temperature recycle blowers, and system control design. Finally, a 4-step development roadmap is proposed for future technology development, the first step being a 1 kW proof-of-concept demonstration unit.

  13. SOFC/TEG hybrid mCHP system. Final report

    Energy Technology Data Exchange (ETDEWEB)

    2012-03-15

    The starting point for this project have been the challenge has been to develop a cost effective solution with long term stability. This is where a focused effort in a strong consortium covering material research, module development and manufacture as well as device design and optimization can make a real difference. In March 2010 the SOFTEG phase II project was initiated and a cooperation organization was established to implement the project as a development and demonstration project involving the staff from all project partners. The project is now completed with excellent and documented outcome. The final results by Alpcon have been demonstration as a TEG-based mCHP system calls CHP Dual Engine Power System, which will be applicable as both a standalone TEG-CHP hybrid system, but also as an auxiliary power unit and power booster for the SOFC system. However the SOFC system cannot cover the household's heat demand alone so it is necessary to combine a SOFC system together with a water heater/boiler system to cover the peak heat demand of a residential house or a complex building. The SOFTEG project partners achieved significant results that mainly can be outlined as following: 1) University of Aarhus has improved the thermal stability of ZnSb by optimizing the concentration of Nano composite material. 2) The grain size and its influence on the sintering process by spark plasma method are investigated by Aarhus University, but further work seems to be necessary. 3) The TE material is going to commercialization by Aarhus University. 4) Aalborg University has prepared simulation tools for complex thermoelectric simulation in non-steady state condition. 5) The new type DCDC interleaved converter using the MPPT system for optimal power tracing is designed, build and tested by Aalborg University in cooperation with Alpcon. This task is included overall system design, control system implementation and power electronic control design. 6) Full scale practical

  14. Efficiency of SOFC type fuel cells; Eficiencia de celulas combustiveis do tipo SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Alexandre Alves do; Matos, Francisco F.; Boaventura, Jaime S.; Benedicto, Joao Paulo S.; Alencar, Marcelo [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica. Dept. de Fisico-Quimica

    2006-07-01

    production of electric energy, mainly due to the fact that it is virtually no pollutant. Typically, the SOFC is constituted of at least seven distinct phases: fuel, anode, electrolyte substrate (separating the two electrodes), cathode, air, and electrical inter connectors (completing the electrical circuit). Thermodynamics clearly shows that electrochemical systems only can be reversible when homogeneous, what it is not case of the Sofc. Therefore, the application of equilibrium thermodynamics to these systems is incorrect. This work proposes that the Sofc can be better depicted from reactions between adsorbed species. The efficiency then is calculated as the ratio between the free energy of these reactions to the combustion heat. Thermodynamic parameter estimative is developed for the global and adsorbed species reactions. (author)

  15. Life cycle assessment of an SOFC/GT process

    Energy Technology Data Exchange (ETDEWEB)

    Olausson, Pernilla

    1999-06-01

    For the last few years much effort has been put into the research on different kinds of fuel cells, since these are considered to be both an efficient and environment friendly way to convert energy. The fuel cell studied here is the solid oxide fuel cell (SOFC) that works at a high temperature (800-1000 C) and today achieves a stand-alone electric efficiency of approximately 50%. When integrating the SOFC in a gas turbine process (SOFC/GT process) an efficiency of 70-75% can be reached. The SOFC and the SOFC/GT process are considered to be environment friendly regarding the discharges during operation. Especially formation of nitrogen oxides (NO{sub x}) is low since the SOFC temperatures are low compared to NO{sub x} formation temperatures. To study the whole environmental impact of the SOFC/GT process a life cycle assessment (LCA) is carried out to find the `hot spots` in the process` life cycle. Since the SOFC/GT process is under development today the collected data are mainly from literature and articles based on laboratory results. When performing the LCA only the SOFC-module and the gas turbine are included. A collection of data of all processes included, extraction of minerals, processing of raw material, production of the components, operation of the SOFC/GT process and transports between all these processes. These data are then added up and weighted in impact categories to evaluate the total environmental impact of the SOFC/GT process. All these steps are performed according to the ISO 14040-series. The stand-alone most contributing phase during the life cycle of the SOFC/GT process was found to be the production of the SOFC. All processes during the production of the SOFC are carried out under laboratory circumstances, which require more energy and materials than if the processes were commercialised and optimised. For the SOFC/GT process to be competitive with other energy converting processes regarding the discharges of emissions to the air, the use of

  16. Development of a fuel flexible, air-regulated, modular, and electrically integrated SOFC-system (FlameSOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Voss, S.; Trimis, D. [TU Bergakademie Freiberg (Germany). Inst. of Thermal Engineering; Valldorf, J. [VDI/VDE Innovation + Technik GmbH (Germany)

    2010-07-01

    The present paper summarizes experimental results from the operation of the SOFC based micro-CHP unit developed within the framework of the project FlameSOFC. The project is co-financed by the European Commission as an Integrated Project within the 6{sup th} framework program. The objective is the development of an innovative SOFC-based micro-CHP system capable of operating with different gaseous and liquid fuels and fulfilling the technological and market requirements at a European level. The partners involved in the FlameSOFC project bring together a sufficient number of important European actors on the scientific, research and industry level including SMEs and industrial partners from the heating sector. The presented work concerns the operation of the 2{sup nd} phase prototype FlameSOFC system, with a 1 kW{sub el.} SOFC stack and natural gas as feedstock. (orig.)

  17. Dynamic model with experimental validation of a biogas-fed SOFC plant

    International Nuclear Information System (INIS)

    D'Andrea, G.; Gandiglio, M.; Lanzini, A.; Santarelli, M.

    2017-01-01

    Highlights: • 60% of DIR into the SOFC anode reduces the air blower parasitic losses by 14%. • PID-controlled cathode airflow enables fast thermal regulation of the SOFC. • Stack overheating occurs due to unexpected reductions in the cathode airflow. • Current ramp rates higher than +0.30 A/min lead to an excessive stack overheating. - Abstract: The dynamic model of a poly-generation system based on a biogas-fed solid oxide fuel cell (SOFC) plant is presented in this paper. The poly-generation plant was developed in the framework of the FP7 EU-funded project SOFCOM ( (www.sofcom.eu)), which consists of a fuel-cell based polygeneration plant with CO_2 capture and re-use. CO_2 is recovered from the anode exhaust of the SOFC (after oxy-combustion, cooling and water condensation) and the Carbon is fixed in the form of micro-algae in a tubular photobioreactor. This work focuses on the dynamic operation of the SOFC module running on steam-reformed biogas. Both steady state and dynamic operation of the fuel cell stack and the related Balance-of-Plant (BoP) has been modeled in order to simulate the thermal behavior and performance of the system. The model was validated against experimental data gathered during the operation of the SOFCOM proof-of-concept showing good agreement with the experimental data. The validated model has been used to investigate further on the harsh off-design operation of the proof-of-concept. Simulation results provide guidelines for an improved design of the control system of the plant, highlighting the feasible operating region under safe conditions and means to maximize the overall system efficiency.

  18. Cathode-Electrolyte Interfaces with CGO Barrier Layers in SOFC

    DEFF Research Database (Denmark)

    Knibbe, Ruth; Hjelm, Johan; Menon, Mohan

    2010-01-01

    Electron microscopy characterization across the cathode–electrolyte interface of two different types of intermediate temperature solid oxide fuel cells (IT-SOFC) is performed to understand the origin of the cell performance disparity. One IT-SOFC cell had a sprayed-cosintered Ce0.90Gd0.01O1.95 (CGO...

  19. Integrating a SOFC Plant with a Steam Turbine Plant

    DEFF Research Database (Denmark)

    Rokni, Masoud; Scappin, Fabio

    2009-01-01

    A Solid Oxide Fuel Cell (SOFC) is integrated with a Steam Turbine (ST) cycle. Different hybrid configurations are studied. The fuel for the plants is assumed to be natural gas (NG). Since the NG cannot be sent to the anode side of the SOFC directly, a desulfurization reactor is used to remove...

  20. Solid Oxide Fuel Cell (SOFC) Development in Denmark

    DEFF Research Database (Denmark)

    Linderoth, Søren; Larsen, Peter Halvor; Mogensen, Mogens Bjerg

    2007-01-01

    on larger anode-supported cells as well as a new generation of SOFCs based on porous metal supports and new electrode and electrolyte materials. The SOFC program comprises development of next generation of cells and multi stack modules for operation at lower temperature with increased durability...

  1. Technology watch of stationary solid oxide fuel cells (SOFC) 2012; Teknikbevakning av stationaera fastoxidbraensleceller (SOFC) 2012

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Martin; Sunden, Bengt

    2013-03-15

    The first solid oxide fuel cell (SOFC) was developed in 1937. However, the commercialization has waited. In 2012, 20MW of SOFC-systems are expected to be delivered to customers, compared to 1.3 MW in 2008. It is mainly in specific niche markets, such as on-site power generation for data centers, small-scale CHP for individual households and as military applications, where SOFC systems are available today. The future potential is enormous in the just mentioned areas as well as for APUs in trucks and other vehicles as well as for MW-scale distributed power generation. There are public research program, support for demonstration projects and investment support to private households as well as companies in various terms around the world. EU invests SEK 666 million (distributed at hydrogen, fuel cells for transportation, stationary systems and cogeneration) in the FCH-JU program only in 2012, compared with SEK 1.59 billion in the Japanese program (of which 125 million is directed to SOFC research and 740 million to the ENE-FARM project to be distributed between PEMFC and SOFC). The German hydrogen and fuel cell program is SEK 12 billion during 2006-2016 (of which 54% to transportation applications, 36% to stationary applications and 10% to special applications), compared with the Finnish program that invest SEK 1.3 billion in 2007-2013. The federal SECA program directs SEK 160 million to SOFC research. Denmark goes slightly over SEK 115 million annually in public funds for fuel cell research. The trend is that the proportion of public funding for demonstration projects and support to customers for purchasing pre-commercial products is increasing at the expense of basic research funding. Note that the listed research programs involve different types of fuel cells, and information regarding the percentage that goes to SOFCs is not specified for each case. Research continues to deliver new advances. Researchers at Harvard have shown that a SOFC, with vanadium oxide in the

  2. SOFC mini-tubulares basadas en YSZ

    Directory of Open Access Journals (Sweden)

    Campana, R.

    2008-08-01

    Full Text Available Tubular SOFC have the advantage over planar SOFC of the low temperature sealing and more resistance to thermal shock. On the other hand the volumetric power density of tubular Fuel Cells goes with the inverse of the tube diameter which added to the faster warm-up kinetics makes low diameter tubular SOFC favorable for low power applications. Anode supported tubular SOFC of 3mm diameter and 150 mm length with YSZ electrolyte were fabricated and tested by V-I measurements using H2-Ar (5, 10, 100 vol% as fuel and air for the cathode. The NiO-YSZ tubes of about 400 μm thickness were produced by hydrostatic pressure and then coated with an YSZ film of 15-20 μm. The electrolyte was deposited using a manual aerograph. After sintering either Pt paste or LSF (with YSZ or SDC coatings of about 20-50 μm thickness were deposited for the cathode. The OCV of the cells were excellent, very close to the expected Nernst law prediction indicating that there were not gas leaks. The maximun electrical power of the cell was near to 500mW/cm2 at 850ºC operation temperature. Complex impedance measurements of the cells were performed in order to determine the resistance of the different cell components.

    La principal ventaja de las SOFC tubulares frente a las planares es el sellado de la cámara anódica y catódica a bajas temperaturas. Además la densidad de energía volumétrica de las pilas tubulares es inversamente proporcional al diámetro del tubo, que añadido a los tiempos cortos de encendido y apagado hacen que las mini-tubulares sean interesantes para usos de baja potencia. Se han fabricado y caracterizado SOFC tubulares soportadas en ánodo de 3mm de diámetro y de 150 mm de longitud, 400μm de espesor, con electrolito de YSZ depositado por spray de 15-20 μm. Los tubos de NiO-YSZ son producidos por prensado isostático. La caracterización eléctrica se ha realizado empleando H2-Ar como combustible an

  3. Solid oxide fuel cells, SOFC, in future power generation; Fastoxidbraensleceller, SOFC, i framtida kraftgenerering

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Kent; Baafaelt, M

    1997-02-01

    Solid Oxide Fuel Cell, SOFC, is a very promising technological area for generating electricity in the future. Especially for small scale cogeneration. SOFC is an excellent choice due to its high efficiencies at small power plant sizes. The expected size of the power plants is 10-20 MWe but larger ones might be built. An important part of the assumptions in this report is the SOFC electric efficiency dependence of the pressure in the process. The electric efficiency is assumed to be 50% at atmospheric pressure and 55% at 10 atmospheres. These assumptions lead to a formula that describes the electric efficiency as a function of the pressure. The parametric study shows that the pressure has a very large influence of the electric efficiency. At low pressure and high Turbine Inlet Temperature (TIT) the electric efficiency will be higher than at high pressure and low TIT. The post intercooler temperature and the pressure drop over the SOFC unit have a moderate effect on the electric efficiency. In the process calculations the TIT is shown to have a very small influence on the plant efficiencies. Consequently, by lowering the TIT, the need for blade cooling and tougher materials can be avoided, with only a small electric efficiency decrease. The recuperator is a central part of the process. It evens out the influence from other parts in the process. This is one of the reasons why the polytropic efficiencies of the compressor and the expander have such a low influence on the process efficiency. The report shows that to receive high efficiencies in a SOFC/GT power plant, the points mentioned below should be taken into consideration: The pressure in the process should be approximately 4 bar; The compressor should have an intercooler; The TIT should be below the temperature where blade cooling is needed; No steam cycle should be connected after the gas turbine at sizes of 5-20 MW. 32 refs, 67 figs, 9 tabs, 15 appendices

  4. Integrated Gasification SOFC Plant with a Steam Plant

    DEFF Research Database (Denmark)

    Rokni, Masoud; Pierobon, Leonardo

    2011-01-01

    A hybrid Solid Oxide Fuel Cell (SOFC) and Steam Turbine (ST) plant is integrated with a gasification plant. Wood chips are fed to the gasification plant to produce biogas and then this gas is fed into the anode side of a SOFC cycle to produce electricity and heat. The gases from the SOFC stacks...... enter into a burner to burn the rest of the fuel. The offgases after the burner are now used to generate steam in a Heat Recovery Steam Generator (HRSG). The generated steam is expanded in a ST to produce additional power. Thus a triple hybrid plant based on a gasification plant, a SOFC plant...... and a steam plant is presented and studied. The plant is called as IGSS (Integrated Gasification SOFC Steam plant). Different systems layouts are presented and investigated. Electrical efficiencies up to 56% are achieved which is considerably higher than the conventional integrated gasification combined...

  5. Study of Operating Parameters for Accelerated Anode Degradation in SOFCs

    DEFF Research Database (Denmark)

    Ploner, Alexandra; Hagen, Anke; Hauch, Anne

    2017-01-01

    Solid oxide fuel cell (SOFC) applications require lifetimes of several years on the system level. A big challenge is to demonstrate such exceptionally long lifetimes in ongoing R&D projects. Accelerated or compressed testing are alternative methods to obtain this. Activities in this area have been...... carried out without arriving at a generally accepted methodology. This is mainly due to the complexity of degradation mechanisms on the single SOFC components as function of operating parameters. In this study, we present a detailed analysis of approx. 180 durability tests regarding degradation of single...... SOFC components as function of operating conditions. Electrochemical impedance data were collected on the fresh and long-term tested SOFCs and used to de-convolute the individual losses of single SOFC cell components – electrolyte, cathode and anode. The main findings include a time-dependent effect...

  6. Development of Robust Metal-Supported SOFCs and Stack Components in EU METSAPP Consortium

    DEFF Research Database (Denmark)

    Sudireddy, Bhaskar Reddy; Nielsen, Jimmi; Persson, Åsa Helen

    2017-01-01

    -SOFCs to enhance their robustness. In addition, the manufacturing of metal-supported cells with different geometries, scalability of the manufacturing process was demonstrated and more than 200 cells with an area of ∼150 cm2 were produced. The electrochemical performance of different cell generations was evaluated...... in 90% reduction in Cr evaporation, three times lower Cr2O3 scale thickness and increased lifetime. The possibility of assembling these cells into two radically different stack designs was demonstrated....

  7. Infiltrated SrTiO3:FeCr‐based Anodes for Metal‐Supported SOFC

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Reddy Sudireddy, Bhaskar; Persson, Åsa Helen

    2013-01-01

    The concept of using electronically conducting anode backbones with subsequent infiltration of electrocatalytic active materials has been used to develop an alternative solid oxide fuel cell (SOFC) design based on a ferritic stainless steel support. The anode backbone consists of a composite made...

  8. Infiltrated SrTiO3:FeCr-based anodes for metalsupported SOFC

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Persson, Åsa Helen; Nielsen, Jimmi

    2012-01-01

    The concept of using highly electronically conducting backbones with subsequent infiltration of electrocatalytic active materials, has recently been used to develop an alternative SOFC design based on a ferritic stainless steel support. The metal-supported SOFC is comprised of porous and highly e...... changes occurring in the anode layer during testing. The results indicate that the STN component in the anode seems to have a positive effect on the corrosion stability of the FeCr-particles in the anode layer.......) and FeCr. Electrochemical characterization and post test SEM analysis have been used to get an insight into the possible degradation mechanisms of this novel electrode infiltrated with Gd-doped CeO2 and Ni. Accelerated oxidation/corrosion experiments have been conducted to evaluate the microstructural...

  9. Optimal integration strategies for a syngas fuelled SOFC and gas turbine hybrid

    Science.gov (United States)

    Zhao, Yingru; Sadhukhan, Jhuma; Lanzini, Andrea; Brandon, Nigel; Shah, Nilay

    This article aims to develop a thermodynamic modelling and optimization framework for a thorough understanding of the optimal integration of fuel cell, gas turbine and other components in an ambient pressure SOFC-GT hybrid power plant. This method is based on the coupling of a syngas-fed SOFC model and an associated irreversible GT model, with an optimization algorithm developed using MATLAB to efficiently explore the range of possible operating conditions. Energy and entropy balance analysis has been carried out for the entire system to observe the irreversibility distribution within the plant and the contribution of different components. Based on the methodology developed, a comprehensive parametric analysis has been performed to explore the optimum system behavior, and predict the sensitivity of system performance to the variations in major design and operating parameters. The current density, operating temperature, fuel utilization and temperature gradient of the fuel cell, as well as the isentropic efficiencies and temperature ratio of the gas turbine cycle, together with three parameters related to the heat transfer between subsystems are all set to be controllable variables. Other factors affecting the hybrid efficiency have been further simulated and analysed. The model developed is able to predict the performance characteristics of a wide range of hybrid systems potentially sizing from 2000 to 2500 W m -2 with efficiencies varying between 50% and 60%. The analysis enables us to identify the system design tradeoffs, and therefore to determine better integration strategies for advanced SOFC-GT systems.

  10. Deposition and characterisation of epitaxial oxide thin films for SOFCs

    KAUST Repository

    Santiso, José ; Burriel, Mó nica

    2010-01-01

    This paper reviews the recent advances in the use of thin films, mostly epitaxial, for fundamental studies of materials for solid oxide fuel cell (SOFC) applications. These studies include the influence of film microstructure, crystal orientation

  11. Hybrid Metal/Electrolyte Monolithic Low Temperature SOFCs

    National Research Council Canada - National Science Library

    Cochran, Joe

    2004-01-01

    The program objective is to develop SOFCs, operating in the 500-700 degrees C range, based on Metal/Electrolyte square cell honeycomb formed by simultaneous powder extrusion of electrolyte and metal...

  12. Study of a SOFC-PEM hybrid system

    International Nuclear Information System (INIS)

    Fillman, B.; Bjornbom, P.; Sylwan, C.

    2004-01-01

    'Full text:' In the present project a system study of a SOFC-PEM hybrid system is in progress. Positive synergy effects are expected when combining a SOFC system with a PEM system. By combining the advantages of each fuel cell type it is promising that the hybrid system has higher overall efficiency than a SOFC-only system or a reformer-PEM system. A SOFC stack produces electricity and a reformate gas that can be further processed to hydrogen by the shift reaction. The produced hydrogen can be used by PEM stack in order to produce further electricity. In the PEM system case the complex fuel reformer processing could be eliminated. The simulations were performed with the flowsheeting simulation software Aspen Plus. (author)

  13. Electrically Conductive and Protective Coating for Planar SOFC Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jung-Pyung; Stevenson, Jeffry W.

    2017-12-04

    Ferritic stainless steels are preferred interconnect materials for intermediate temperature SOFCs because of their resistance to oxidation, high formability and low cost. However, their protective oxide layer produces Cr-containing volatile species at SOFC operating temperatures and conditions, which can cause cathode poisoning. Electrically conducting spinel coatings have been developed to prevent cathode poisoning and to maintain an electrically conductive pathway through SOFC stacks. However, this coating is not compatible with the formation of stable, hermetic seals between the interconnect frame component and the ceramic cell. Thus, a new aluminizing process has been developed by PNNL to enable durable sealing, prevent Cr evaporation, and maintain electrical insulation between stack repeat units. Hence, two different types of coating need to have stable operation of SOFC stacks. This paper will focus on the electrically conductive coating process. Moreover, an advanced coating process, compatible with a non-electrically conductive coating will be

  14. SOFC anode reduction studied by in situ TEM

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Wagner, Jakob Birkedal; Hansen, Thomas Willum

    The Solid Oxide Fuel Cell (SOFC) is a promising part of future energy approaches due to a relatively high energy conversion efficiency and low environmental pollution. SOFCs are typically composed of ceramic materials which are highly complex at the nanoscale. TEM is routinely applied ex situ...... for studying these nanoscale structures, but only few SOFC studies have applied in situ TEM to observe the ceramic nanostructures in a reactive gas environment at elevated temperatures. The present contribution focuses on the reduction of an SOFC anode which is a necessary process to form the catalytically...... active Ni surface before operating the fuel cells. The reduction process was followed in the TEM while exposing a NiO/YSZ (YSZ = Y2O3-stabilized ZrO2) model anode to H2 at T = 250-1000⁰C. Pure NiO was used in reference experiments. Previous studies have shown that the reduction of pure Ni...

  15. Dynamic Analysis of Load Operations of Two-Stage SOFC Stacks Power Generation System

    Directory of Open Access Journals (Sweden)

    Paulina Pianko-Oprych

    2017-12-01

    Full Text Available The main purpose of this paper was to develop a complete dynamic model of a power generation system based on two serially connected solid oxide fuel cell stacks. The uniqueness of this study lies in a different number of fuel cells in the stacks. The model consists of the electrochemical model, mass and energy balance equations implemented in MATLAB Simulink environment. Particular attention has been paid to the analysis of the transient response of the reformers, fuel cells and the burner. The dynamic behavior of the system during transient conditions was investigated by load step changing. The model evaluates electrical and thermal responses of the system at variable drawn current. It was found that a decrease of 40% in the 1st stage and 2nd solid oxide fuel cell (SOFC stacks drawn current caused both stacks temperature to drop by 2%. An increase of the cell voltage for the 1st and 2nd SOFC stacks led to very fast steam reformer response combined with a slight decrease in reformer temperature, while a considerable burner temperature increase of 70 K can be observed. Predictions of the model provide the basic insight into the operation of the power generation-based SOFC system during various transients and support its further design modifications.

  16. Analysis of cathode materials of perovskite structure for solid oxide fuel cells, sofc s; Analisis de materiales catodicos de estructura perovskita para celdas de combustible de oxido solido, sofcs

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado F, J.; Espino V, J.; Avalos R, L. [Universidad Michoacana de San Nicolas de Hidalgo, Facultad de Ingenieria Quimica, Santiago Tapia 403, Morelia, Michoacan (Mexico)

    2015-07-01

    Fuel cells directly and efficiently convert the chemical energy of a fuel into electrical energy. Of the various types of fuel cells, the solid oxide (Sofc), combine the advantages in environmentally benign energy generation with fuel flexibility. However, the need for high operating temperatures (800 - 1000 grades C) has resulted in high costs and major challenges in relation to the compatibility the cathode materials. As a result, there have been significant efforts in the development of intermediate temperature Sofc (500 - 700 grades C). A key obstacle for operation in this temperature range is the limited activity of traditional cathode materials for electrochemical reduction oxygen. In this article, the progress of recent years is discussed in cathodes for Sofc perovskite structure (ABO{sub 3}), more efficient than the traditionally used La{sub 1-x}Sr{sub x}MnO{sub 3-δ} (LSM) or (La, Sr) CoO{sub 3}. Such is the case of mixed conductors (MIEC) double perovskite structure (A A B{sub 2}O{sub 5+δ}) using different doping elements as La, Sr, Fe, Ti, Cr, Sm, Co, Cu, Pr, Nd, Gd, dy, Mn, among others, which could improve the operational performance of existing cathode materials, promoting the development of optimized intermediate temperature Sofc designs. (Author)

  17. Characterization of ceria-based SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Doshi, R.; Routbort, J.; Krumpelt, M. [Argonne National Lab., IL (United States)

    1996-12-31

    Solid Oxide Fuel Cells (SOFCs) operating at low temperatures (500-700{degrees}C) offer many advantages over the conventional zirconia-based fuel cells operating at higher temperatures. Reduced operating temperatures result in: (1) Application of metallic interconnects with reduced oxidation problems (2) Reduced time for start-up and lower energy consumption to reach operating temperatures (3) Increased thermal cycle ability for the cell structure due to lower thermal stresses of expansion mismatches. While this type of fuel cell may be applied to stationary applications, mobile applications require the ability for rapid start-up and frequent thermal cycling. Ceria-based fuel cells are currently being developed in the U.K. at Imperial College, Netherlands at ECN, and U.S.A. at Ceramatec. The cells in each case are made from a doped ceria electrolyte and a La{sub 1-x}Sr{sub x}Co{sub 1-y}Fe{sub y}O{sub 3} cathode.

  18. Development status of planar SOFCs at Sanyo

    Energy Technology Data Exchange (ETDEWEB)

    Miyake, Yasuo; Akiyama, Yukinori; Yasuo, Takashi [SANYO Electric Co., Ltd., Osaka (Japan)] [and others

    1996-12-31

    A 2 kW class combined cell stacked module (182 cm{sup 2} X 4X 17) was examined. An output power of 2.47 kW and output power density of 0.20 W/cm{sup 2} were obtained at the current density of 0.3 A/cm{sup 2}. The temperature uniformity is an important factor to develop large scale SOFC modules. Therefore, in this 2 kW class module, one cell was divided into four smaller unit cells to decrease temperature difference across these cells. Moreover, an internal heat-exchanging duct was arranged to spend the surplus heat effectively in the middle of the module. As for the basic research, the followings were investigated to improve thermal cycle characteristics. One was to adopt a silica/alumina-based sealing, material in order to absorb the thermal expansion difference between the electrolyte and the separator. Deterioration was quite small after 12 thermal cycles with a 150 by 150 mm single cell. The other was to use a heat-resisting ferritic alloy as a separator in a 50 by 50 mm single cell in order to decrease the thermal expansion coefficient of the separator. High performance was obtained for 2000 hours at 900{degrees}C in an endurance test and deterioration was quite small after a thermal cycle.

  19. Development of cofired type planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Taira, Hiroaki; Sakamoto, Sadaaki; Zhou, Hua-Bing [Murata Manufacturing Co., Ltd., Shiga (Japan)] [and others

    1996-12-31

    We have developed fabrication process for planar SOFC fabricated with cofired anode/electrolyte/cathode multilayers and interconnects. By cofiring technique for the multilayers, we expect to reduce the thickness of the electrolyte layers, resulting in decrease of innerimpedance, and achieve low production cost. On the other hand, the cofiring technique requires that the sintering temperature, the shrinkage profiles and the thermal expansion characteristics of all component materials should be compatible with the other. It is, therefore, difficult to cofire the multilayers with large area. Using the multilayers with surface area of 150cm{sup 2}, we fabricated the multiple cell stacks. The maximum power of 5x4 multiple cell stack (5 planes of cells in series, 4 cells in parallel in each planes 484cm{sup 2} effective electrode area of each cell planes) was 601W (0.25Wcm{sup -2}, Uf=40%). However, the terminal voltage of the multiple cell stack decreased by the cause of cell cracking, gas leakage and degradation of cofired multilayers. This paper presents the improvements of cofired multilayers, and the performance of multiple cell stacks with the improved multilayers.

  20. System requirements of diesel reforming for the SOFC

    International Nuclear Information System (INIS)

    Harasti, P.T.; Amphlett, J.C.; Mann, R.F.; Peppley, B.A.; Thurgood, C.P.

    2003-01-01

    Diesel fuels are currently a very attractive source of hydrogen due to the global infrastructure for production and distribution that exists today. In order to extract the hydrogen, the hydrocarbon molecules must be chemically reformed into manageable, hydrogen-rich product gases that can be directly used in electrochemical energy conversion devices such as fuel cells. High temperature fuel cells are particularly attractive for diesel-fuelled systems due to the possibility of thermal integration with the high temperature reformer. The methods available for diesel fuel processing are: Steam Reforming, Partial Oxidation, and Auto-Thermal Reforming. The latter two methods introduce air into the process in order to cause exothermic oxidation reactions, which complement the endothermic heating requirement of the reforming reactions. This helps to achieve the high temperature required, but also introduces nitrogen, which can yield unwanted NO x emissions. The components of the reformer should include: an injection system to mix and vaporize the diesel fuel and steam while avoiding the formation of carbon deposits inside the reactor; a temperature and heat management system; and a method of sulphur removal. This presentation will discuss the operating conditions and design requirements of a diesel fuel processor for a solid oxide fuel cell (SOFC) system. (author)

  1. Manufacturing of anode supported SOFCs: Processing parameters and their influence

    DEFF Research Database (Denmark)

    Ramousse, Severine; Menon, Mohan; Brodersen, Karen

    2007-01-01

    The establishment of low cost, highly reliable and reproducible manufacturing processes has been focused for commercialization of SOFC technology. A major challenge in the production chain is the manufacture of anode-supported planar SOFC's single cells in which each layer in a layered structure...... contains a complex microstructure. In order to improve the cell performance as well as reducing the processing costs, it has been found necessary to consider the process chain holistically, because successful manufacture of such a cell and the achievement of optimal final properties depend on each...... of the processing steps and their interdependence. A large database for several thousand anode-supported SOFCs manufactured annually at the Risoe National Laboratory in collaboration with Topsoe Fuel Cell A/S has been constructed. This enables a statistical analysis of the various controlling parameters. Some...

  2. High temperature sealing method : induction brazing for SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Y.H.; Lee, S.B.; Song, R.H.; Shin, D.R. [Korea Inst. of Energy Research, Daejeon (Korea, Republic of); Lim, T.H. [Korea Inst. of Energy Research, Daejeon (Korea, Republic of). Advanced Fuel Cell Research Center

    2009-07-01

    This study examined the use of induction brazing as a high temperature sealing method for solid oxide fuel cells (SOFCs). Nickel-based brazing alloys were modified using reactive titanium-hydride (TiH2). The gas sealing properties of the induction brazing process on anode-supported tubular SOFCs and ferritic stainless steel were evaluated. Brazing alloys BNi-2 and BNi-4 were not wetted in a yttria-silica-zircon (YSZ) electrolyte. The brazing alloy with added TiH2 showed good wettability with the YSZ electrolyte as a result of the formation of a TiOX layer. Only the BNi-4 alloy joined with the YSZ electrolyte. An open circuit voltage (OCV) value was used to estimate the gas tightness of the brazed cell. It was concluded that the BNi-4 TiH2 modified alloy is a suitable sealing material for SOFCs operating in temperatures up to 750 degrees C.

  3. Deposition and characterisation of epitaxial oxide thin films for SOFCs

    KAUST Repository

    Santiso, José

    2010-10-24

    This paper reviews the recent advances in the use of thin films, mostly epitaxial, for fundamental studies of materials for solid oxide fuel cell (SOFC) applications. These studies include the influence of film microstructure, crystal orientation and strain in oxide ionic conducting materials used as electrolytes, such as fluorites, and in mixed ionic and electronic conducting materials used as electrodes, typically oxides with perovskite or perovskite-related layered structures. The recent effort towards the enhancement of the electrochemical performance of SOFC materials through the deposition of artificial film heterostructures is also presented. These thin films have been engineered at a nanoscale level, such as the case of epitaxial multilayers or nanocomposite cermet materials. The recent progress in the implementation of thin films in SOFC devices is also reported. © 2010 Springer-Verlag.

  4. In-Situ Raman Characterization of SOFC Anodes

    KAUST Repository

    Maher, Robert C.; Offer, Gregory; Brandon, Nigel P.; Cohen, Lesley F.

    2012-01-01

    Solid oxide fuel cells (SOFCs) have many advantages when compared to other fuel cell technologies, particularly for distributed stationary applications. As a consequence they are becoming ever more economically competitive with incumbent energy solutions. However, as with all technologies, improvements in durability, efficiency and cost is required before they become feasible alternatives. Such improvements are enabled through improved understanding of the critical material interactions occurring during operation. Raman spectroscopy is a noninvasive and non-destructive optical characterization tool which is ideally suited to the study of these critical chemical processes occurring within operational SOFCs. In this paper we will discuss advantages of using Raman characterization for understanding these important chemical processes occurring within SOFCs. We will present the specific examples of the type of measurement possible and discuss the direction of future research. © 2012 Materials Research Society.

  5. Synchrotron Investigations of SOFC Cathode Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Idzerda, Yves

    2013-09-30

    The atomic variations occurring in cathode/electrolyte interface regions of La{sub 1-x}Sr{sub x}Co{sub y}Fe{sub 1-y}O{sub 3-δ} (LSCF) cathodes and other SOFC related materials have been investigated and characterized using soft X-ray Absorption Spectroscopy (XAS) and diffuse soft X-ray Resonant Scattering (XRS). X-ray Absorption Spectroscopy in the soft X-ray region (soft XAS) is shown to be a sensitive technique to quantify the disruption that occurs and can be used to suggest a concrete mechanism for the degradation. For LSC, LSF, and LSCF films, a significant degradation mechanism is shown to be Sr out-diffusion. By using the XAS spectra of hexavalent Cr in SrCrO4 and trivalent Cr in Cr2O3, the driving factor for Sr segregation was identified to be the oxygen vacancy concentration at the anode and cathode side of of symmetric LSCF/GDC/LSCF heterostructures. This is direct evidence of vacancy induced cation diffusion and is shown to be a significant indicator of cathode/electrolyte interfacial degradation. X-ray absorption spectroscopy is used to identify the occupation of the A-sites and B-sites for LSC, LSF, and LSCF cathodes doped with other transition metals, including doping induced migration of Sr to the anti-site for Sr, a significant cathode degradation indicator. By using spatially resolved valence mapping of Co, a complete picture of the surface electrochemistry can be determined. This is especially important in identifying degradation phenomena where the degradation is spatially localized to the extremities of the electrochemistry and not the average. For samples that have electrochemical parameters that are measured to be spatially uniform, the Co valence modifications were correlated to the effects of current density, overpotential, and humidity.

  6. Thermal stress analysis of a planar SOFC stack

    Science.gov (United States)

    Lin, Chih-Kuang; Chen, Tsung-Ting; Chyou, Yau-Pin; Chiang, Lieh-Kwang

    The aim of this study is, by using finite element analysis (FEA), to characterize the thermal stress distribution in a planar solid oxide fuel cell (SOFC) stack during various stages. The temperature profiles generated by an integrated thermo-electrochemical model were applied to calculate the thermal stress distributions in a multiple-cell SOFC stack by using a three-dimensional (3D) FEA model. The constructed 3D FEA model consists of the complete components used in a practical SOFC stack, including positive electrode-electrolyte-negative electrode (PEN) assembly, interconnect, nickel mesh, and gas-tight glass-ceramic seals. Incorporation of the glass-ceramic sealant, which was never considered in previous studies, into the 3D FEA model would produce more realistic results in thermal stress analysis and enhance the reliability of predicting potential failure locations in an SOFC stack. The effects of stack support condition, viscous behavior of the glass-ceramic sealant, temperature gradient, and thermal expansion mismatch between components were characterized. Modeling results indicated that a change in the support condition at the bottom frame of the SOFC stack would not cause significant changes in thermal stress distribution. Thermal stress distribution did not differ significantly in each unit cell of the multiple-cell stack due to a comparable in-plane temperature profile. By considering the viscous characteristics of the glass-ceramic sealant at temperatures above the glass-transition temperature, relaxation of thermal stresses in the PEN was predicted. The thermal expansion behavior of the metallic interconnect/frame had a greater influence on the thermal stress distribution in the PEN than did that of the glass-ceramic sealant due to the domination of interconnect/frame in the volume of a planar SOFC assembly.

  7. Aluminosilicate-based sealants for SOFCs and other electrochemical applications - A brief review

    Science.gov (United States)

    Tulyaganov, Dilshat U.; Reddy, Allu Amarnath; Kharton, Vladislav V.; Ferreira, José M. F.

    2013-11-01

    Among different designs of solid oxide fuel cells (SOFCs), planar design is the most promising due to easier fabrication, improved performance and relatively high power density. In planar SOFCs and other solid-electrolyte devices, gas-tight seals must be formed along the edges of each cell and between the stack and gas manifolds. For a sealant to work effectively in high-temperature SOFC environment, equilibrium needs to be achieved amid its mechanical properties and flow behavior so that it does not only maintain its hermeticity at high temperature but is also able to reduce mechanical stresses generated in the seal during thermal cycling. The most common sealants based on glass or glass-ceramic materials have been shown to operate in fuel cells for more than 1000 h with no significant degradation. Analysis of the current literature sources demonstrated that from thermal and chemical stability points of view, silicate based glass systems are more suitable than borate and borosilicate glass systems. In this work, different glass-ceramic (GC) compositions based on alkaline- and alkaline-earth aluminosilicate-based glass systems are reviewed with a special emphasis on their thermal, chemical, mechanical, and electrical properties. Based on these considerations, glass composition design approaches are provided that aid in search of the best seal glasses satisfying the rigid functional requirements. Among all the glass systems studied, a pyroxene based CaO-MgO-SrO-BaO-La2O3-Al2O3-SiO2 seal GC compositions have been specifically discussed because those have achieved appropriate thermal and chemical properties along with high stability. Approaches for further developments and optimization of GC sealants are briefly discussed.

  8. Fuel flow distribution in SOFC stacks revealed by impedance spectroscopy

    DEFF Research Database (Denmark)

    Mosbæk, Rasmus Rode; Hjelm, Johan; Barfod, Rasmus

    2014-01-01

    As SOFC technology is moving closer to a commercial break through, methods to measure the “state-of-health” of operating stacks are becoming of increasing interest. This requires application of advanced methods for detailed electrical and electrochemical characterization during operation. An oper......As SOFC technology is moving closer to a commercial break through, methods to measure the “state-of-health” of operating stacks are becoming of increasing interest. This requires application of advanced methods for detailed electrical and electrochemical characterization during operation...... utilizations. The fuel flow distribution provides important information about the operating limits of the stack when high electrical efficiency is required....

  9. Study of variables for accelerating lifetime testing of SOFCs

    DEFF Research Database (Denmark)

    Ploner, Alexandra; Hagen, Anke; Hauch, Anne

    Solid oxide fuel cell (SOFC) applications require lifetimes of several years on the system level. A big challenge is to proof/confirm/demonstrate such exceptionally long lifetimes.Accelerated or compressed testing are possible methods. Activities in this area have been carried out without arriving...... at different current load cycling profiles revealed a strong deviation between predicted and measured lifetime [3].In this study, we present a detailed analysis of durability results for degradation mechanisms of single SOFC components as function of operating conditions. Electrochemical impedance data...

  10. Thermodynamic analysis of SOFC (solid oxide fuel cell) - Stirling hybrid plants using alternative fuels

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2013-01-01

    A novel hybrid power system (∼10 kW) for an average family home is proposed. The system investigated contains a solid oxide fuel cell (SOFC) on top of a Stirling engine. The off-gases produced in the SOFC cycle are fed to a bottoming Stirling engine, at which additional power is generated...... to that of a stand-alone Stirling engine or SOFC plant. For the combined SOFC and Stirling configuration, the overall power production was increased by approximately 10% compared to that of a stand-alone SOFC plant. System efficiencies of approximately 60% are achieved, which is remarkable for such small plant sizes...

  11. Plant Characteristics af a Multi-Fuel Sofc-Stirling Hybrid Configuration

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2012-01-01

    A novel hybrid system ( kWe) for an average family house including heating is proposed. The system investigated, contains of a Solid Oxide Fuel Cell (SOFC) on top of a Stirling engine. The off-gases produced in the SOFC cycle is fed to the bottoming Stirling engine wherein additional power...... efficiency compared with the stand alone Stirling engine or SOFC plant. For the SOFC and Stirling combined configuration, the overall power production has increased by about 10% compared to the stand alone SOFC plant. System efficiencies of about 60% are achieved which is remarkable for such small plant...

  12. Effects of Pretreatment Methods on Electrodes and SOFC Performance

    Directory of Open Access Journals (Sweden)

    Guo-Bin Jung

    2014-06-01

    Full Text Available Commercially available tapes (anode, electrolyte and paste (cathode were choosen to prepare anode-supported cells for solid oxide fuel cell applications. For both anode-supported cells or electrolyte-supported cells, the anode needs pretreatment to reduce NiO/YSZ to Ni/YSZ to increase its conductivity as well as its catalytic characteristics. In this study, the effects of different pretreatments (open-circuit, closed-circuit on cathode and anodes as well as SOFC performance are investigated. To investigate the influence of closed-circuit pretreatment on the NiO/YSZ anode alone, a Pt cathode is utilized as reference for comparison with the LSM cathode. The characterization of the electrical resistance, AC impedance, and SOFC performance of the resulting electrodes and/or anode-supported cell were carried out. It’s found that the influence of open-circuit pretreatment on the LSM cathode is limited. However, the influence of closed-circuit pretreatment on both the LSM cathode and NiO/YSZ anode and the resulting SOFC performance is profound. The effect of closed-circuit pretreatment on the NiO/YSZ anode is attributed to its change of electronic/pore structure as well as catalytic characteristics. With closed-circuit pretreatment, the SOFC performance improved greatly from the change of LSM cathode (and Pt reference compared to the Ni/YSZ anode.

  13. Multilayer tape cast SOFC – Effect of anode sintering temperature

    DEFF Research Database (Denmark)

    Hauch, Anne; Birkl, Christoph; Brodersen, Karen

    2012-01-01

    Multilayer tape casting (MTC) is considered a promising, cost-efficient, up-scalable shaping process for production of planar anode supported solid oxide fuel cells (SOFC). Multilayer tape casting of the three layers comprising the half cell (anode support/active anode/electrolyte) can potentially...

  14. Simulation of SOFCs based power generation system using Aspen

    Directory of Open Access Journals (Sweden)

    Pianko-Oprych Paulina

    2017-12-01

    Full Text Available This study presents a thermodynamic Aspen simulation model for Solid Oxide Fuel Cells, SOFCs, based power generation system. In the first step, a steady-state SOFCs system model was developed. The model includes the electrochemistry and the diffusion phenomena. The electrochemical model gives good agreement with experimental data in a wide operating range. Then, a parametric study has been conducted to estimate effects of the oxygen to carbon ratio, O/C, on reformer temperature, fuel cell temperature, fuel utilization, overall fuel cell performance, and the results are discussed in this paper. In the second step, a dynamic analysis of SOFCs characteristic has been developed. The aim of dynamic modelling was to find the response of the system against the fuel utilization and the O/C ratio variations. From the simulations, it was concluded that both developed models in the steady and dynamic state were reasonably accurate and can be used for system level optimization studies of the SOFC based power generation system.

  15. Technical development and economic valuation of new cooling methods for planar solid oxide fuel cells (SOFC)

    International Nuclear Information System (INIS)

    Thom, F.

    2002-02-01

    A great potential exists for the use of the solid oxide fuel cell technology based on the planar cell design concept. Besides its application as power provider there is a need to supply process heat in the temperature range of 200 to 1200 C for commercial and industrial decentralized facilities. The present study is concerned with the technical development and economic valuation of plant concepts of new fuel cell cooling methods. They can be considered as an alternative to the normal convective cell cooling with air. Besides experimental studies on the natural gas reforming with the SOFC special attention is paid to the process analysis of the power plant carried out with the simulating program PROII. The 200 kWe SOFC is linked with peripheral components such as prereformer, heat exchangers, compressors etc. Developed program subroutine serve to calculate the electrical power output of the fuel cell, the investment costs and the costs of electricity. The study shows clearly that a radiative cell cooling device on basis of an external arranged vaporizer has economic benefits in comparison with the normal air cooling. In this case the possibility is given to run the fuel cell with completely prereformed natural gas. When the internal methane reforming is carried out in excess of the electrochemical demand for hydrogen and carbon monoxide respectively a further cost reduction potential is given. The produced synthesis gas can be used in alternative to the production of power in a gas turbine to supply process steam in the temperature range of 200 to 1200 C. Sensitivity analyses show that a successive use of optimization potentials (e.g. anode structure and operating parameters of the SOFC) leads to a further reduction of the costs of electricity. In the best case the achieved costs of 12 to 13 Pf/kWh are in a range achieved by CHP plants based on engines. (orig.) [de

  16. Investigation of Performance of SCN-1 Pure Glass as Sealant Used in SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenning N.; Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2010-03-01

    As its name implies, self-healing glass seal has the potential of restoring its mechanical properties upon being reheated to stack operating temperature, even when it has experienced some cooling induced damage/crack at room temperature. Such a self-healing feature is desirable for achieving high seal reliability during thermal cycling. On the other hand, self-healing glass is also characterized by its low mechanical stiffness and high creep rate at the typical operating temperature of SOFCs. Therefore, from a design’s perspective, it is important to know the long term geometric stability and thermal mechanical behaviors of the self-healing glass under the stack operating conditions. These predictive capabilities will guide the design and optimization of a reliable sealing system that potentially utilizes self-healing glass as well as other ceramic seal components in achieving the ultimate goal of SOFC. In this report, we focused on predicting the effects of various generic seal design parameters on the stresses in the seal. For this purpose, we take the test cell used in the leakage test for compliant glass seals conducted in PNNL as our initial modeling geometry. The effect of the ceramic stopper on the geometry stability of the self-healing glass sealants is studied first. Then we explored the effect of various interfaces such as stopper and glass, stopper and PEN, as well stopper and IC plate, on the geometry stability and reliability of glass during the operating and cooling processes.

  17. The modeling and simulation of thermal based modified solid oxide fuel cell (SOFC for grid-connected systems

    Directory of Open Access Journals (Sweden)

    Ayetül Gelen

    2015-05-01

    Full Text Available This paper presents a thermal based modified dynamic model of a Solid Oxide Fuel Cell (SOFC for grid-connected systems. The proposed fuel cell model involves ohmic, activation and concentration voltage losses, thermal dynamics, methanol reformer, fuel utilization factor and power limiting module. A power conditioning unit (PCU, which consists of a DC-DC boost converter and a DC-AC voltage-source inverter (VSI, their controller, transformer and filter, is designed for grid-connected systems. The voltage-source inverter with six Insulated Gate Bipolar Transistor (IGBT switches inverts the DC voltage that comes from the converter into a sinusoidal voltage synchronized with the grid. The simulations and modeling of the system are developed on Matlab/Simulink environment. The performance of SOFC with converter is examined under step and random load conditions. The simulation results show that the designed boost converter for the proposed thermal based modified SOFC model has fairly followed different DC load variations. Finally, the AC bus of 400 Volt and 50 Hz is connected to a single-machine infinite bus (SMIB through a transmission line. The real and reactive power managements of the inverter are analyzed by an infinite bus system. Thus, the desired nominal values are properly obtained by means of the inverter controller.

  18. Study of a hybrid system using solid oxide fuel cells (SOFC) and gas turbine; Estudo de um sistema hibrido empregando celula de combustivel de oxido solido (SOFC) e turbina a gas

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Antonio Carlos Caetano de; Gallo, Giulliano Batelochi; Silveira, Jose Luz [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Energia], e-mail: caetano@feg.unesp.br

    2004-07-01

    In this paper a hybrid solid oxide fuel cell (SOFC) system, applying a combined cycle using gas turbine for rational decentralized energy production is analyzed. The relative concepts about the fuel cell are presented, followed by some chemical and technical information such as the change of Gibbs free energy in isothermal fuel oxidation directly into electricity. This represents a very high fraction of the lower heating value (LHV) of a hydrocarbon fuel. In the next step a methodology for the study of SOFC and gas turbine system is developed, considering the electricity and steam production for a hospital. This methodology is applied to energetic analysis. Natural gas is considered as a fuel. A Sankey Diagram shows that the hybrid SOFC system is a good opportunity to strengthen the decentralized energy production in Brazil. It is necessary to consider that the cogeneration in this version also is a good technical alternative, demanding special methods of design, equipment selection and contractual deals associated to electricity and fuel supply. (author)

  19. Air plasma spray processing and electrochemical characterization of SOFC composite cathodes

    Science.gov (United States)

    White, B. D.; Kesler, O.; Rose, Lars

    Air plasma spraying has been used to produce porous composite cathodes containing (La 0.8Sr 0.2) 0.98MnO 3- y (LSM) and yttria-stabilized zirconia (YSZ) for use in solid oxide fuel cells (SOFCs). Preliminary investigations focused on determining the range of plasma conditions under which each of the individual materials could be successfully deposited. A range of conditions was thereby determined that was suitable for the deposition of a composite cathode from pre-mixed LSM and YSZ powders. A number of composite cathodes were produced using different combinations of parameter values within the identified range according to a Uniform Design experimental grid. Coatings were then characterized for composition and microstructure using EDX and SEM. As a result of these tests, combinations of input parameter values were identified that are best suited to the production of coatings with microstructures appropriate for use in SOFC composite cathodes. A selection of coatings representative of the types of observed microstructures were then subjected to electrochemical testing to evaluate the performance of these cathodes. From these tests, it was found that, in general, the coatings that appeared to have the most suitable microstructures also had the highest electrochemical performances, provided that the deposition efficiency of both phases was sufficiently high.

  20. Air plasma spray processing and electrochemical characterization of SOFC composite cathodes

    Energy Technology Data Exchange (ETDEWEB)

    White, B.D. [Department of Mechanical Engineering, The University of British Columbia, 2054-6250 Applied Sciences Lane, Vancouver, British Columbia (Canada); Kesler, O. [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario (Canada); Rose, Lars [Department of Materials Engineering, The University of British Columbia, 309-6350 Stores Road, Vancouver, British Columbia (Canada); National Research Council (Canada)

    2008-03-15

    Air plasma spraying has been used to produce porous composite cathodes containing (La{sub 0.8}Sr{sub 0.2}){sub 0.98}MnO{sub 3-y} (LSM) and yttria-stabilized zirconia (YSZ) for use in solid oxide fuel cells (SOFCs). Preliminary investigations focused on determining the range of plasma conditions under which each of the individual materials could be successfully deposited. A range of conditions was thereby determined that was suitable for the deposition of a composite cathode from pre-mixed LSM and YSZ powders. A number of composite cathodes were produced using different combinations of parameter values within the identified range according to a Uniform Design experimental grid. Coatings were then characterized for composition and microstructure using EDX and SEM. As a result of these tests, combinations of input parameter values were identified that are best suited to the production of coatings with microstructures appropriate for use in SOFC composite cathodes. A selection of coatings representative of the types of observed microstructures were then subjected to electrochemical testing to evaluate the performance of these cathodes. From these tests, it was found that, in general, the coatings that appeared to have the most suitable microstructures also had the highest electrochemical performances, provided that the deposition efficiency of both phases was sufficiently high. (author)

  1. A Fuzzy-Based PI Controller for Power Management of a Grid-Connected PV-SOFC Hybrid System

    Directory of Open Access Journals (Sweden)

    Shivashankar Sukumar

    2017-10-01

    Full Text Available Solar power generation is intermittent in nature. It is nearly impossible for a photovoltaic (PV system to supply power continuously and consistently to a varying load. Operating a controllable source like a fuel cell in parallel with PV can be a solution to supply power to variable loads. In order to coordinate the power supply from fuel cells and PVs, a power management system needs to be designed for the microgrid system. This paper presents a power management system for a grid-connected PV and solid oxide fuel cell (SOFC, considering variation in the load and solar radiation. The objective of the proposed system is to minimize the power drawn from the grid and operate the SOFC within a specific power range. Since the PV is operated at the maximum power point, the power management involves the control of SOFC active power where a proportional and integral (PI controller is used. The control parameters of the PI controller Kp (proportional constant and Ti (integral time constant are determined by the genetic algorithm (GA and simplex method. In addition, a fuzzy logic controller is also developed to generate appropriate control parameters for the PI controller. The performance of the controllers is evaluated by minimizing the integral of time multiplied by absolute error (ITAE criterion. Simulation results showed that the fuzzy-based PI controller outperforms the PI controller tuned by the GA and simplex method in managing the power from the hybrid source effectively under variations of load and solar radiation.

  2. Niobium-doped strontium titanates as SOFC anodes

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Kammer Hansen, Kent; Wallenberg, L. Reine

    2008-01-01

    been synthesized with a recently developed modified glycine-nitrate process. The synthesized powders have been calcined and sintered in air or in 9% H(2) / N(2) between 800 - 1400 degrees C. After calcination the samples were single phase Nb-doped strontium titanate with grain sizes of less than 100 nm...... in diameter on average. The phase purity, defect structure, and microstructure of the materials have been analyzed with SEM, XRD, and TGA. The electrical conductivity of the Nb-doped titanate decreased with increasing temperature and showed a phonon scattering conduction mechanism with sigma > 120 S...... ability of the Nb-doped titanates to be used as a part of a SOFC anode. However, the catalytic activity of the materials was not sufficient and it needs to be improved if titanate based materials are to be realized as constituents in SOFC anodes....

  3. In-Situ Optical Studies of Oxidation/Reduction Kinetics on SOFC Cermet Anodes

    Science.gov (United States)

    2010-12-28

    DATES COVERED (From - To) 1/29/10-9/30/10 4. TITLE AND SUBTITLE In situ optical studies of oxidation/reduction kinetics on SOFC cermet anodes 5a...0572 In-situ Optical Studies of Oxidation/Reduction Kinetics on SOFC Cermet Anodes Department of Chemistry and Biochemistry Montana State University...of Research In-situ Optical Studies of Oxidation/Reduction Kinetics on SOFC Cermet Anodes Principal Investigator Robert Walker Organization

  4. Thermal plasma spraying for SOFCs: Applications, potential advantages, and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Rob; Wang, Zhenwei; Jankovic, Jasna; Yick, Sing; Maric, Radenka; Ghosh, Dave [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Kesler, Olivera [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Department of Mechanical Engineering, University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC V6T 1Z4 (Canada); Rose, Lars [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Department of Materials Engineering, University of British Columbia, 309-6350 Stores Road, Vancouver, BC V6T 1Z4 (Canada)

    2007-07-10

    In this article, the applications, potential advantages, and challenges of thermal plasma spray (PS) processing for nanopowder production and cell fabrication of solid oxide fuel cells (SOFCs) are reviewed. PS processing creates sufficiently high temperatures to melt all materials fed into the plasma. The heated material can either be quenched into oxide powders or deposited as coatings. This technique has been applied to directly deposit functional layers as well as nanopowder for SOFCs application. In particularly, low melting point and highly active electrodes can be directly fabricated on zirconia-based electrolytes. This is a simple processing technique that does not require the use of organic solvents, offering the opportunity for flexible adjustment of process parameters, and significant time saving in production of the cell and cost reduction compared with tape casting, screen printing and sintering processing steps. Most importantly, PS processing shows strong potential to enable the deposition of metal-supported SOFCs through the integrated fabrication of membrane-electrode assemblies (MEA) on porous metallic substrates with consecutive deposition steps. On the other hand, the application of PS processing to produce SOFCs faces some challenges, such as insufficient porosity of the electrodes, the difficulty of obtaining a thin (<10 {mu}m) and dense electrolyte layer. Fed with H{sub 2} as the fuel gas and oxygen as the oxidant gas, the plasma sprayed cell reached high power densities of 770 mW cm{sup -2} at 900 C and 430 mW cm{sup -2} at 800 C at a cell voltage of 0.7 V. (author)

  5. Manufacture of SOFC electrodes by wet powder spraying

    Energy Technology Data Exchange (ETDEWEB)

    Wilkenhoener, R.; Mallener, W.; Buchkremer, H.P. [Forschungszentrum Juelich GmbH (Germany)] [and others

    1996-12-31

    The reproducible and commercial manufacturing of electrodes with enhanced electrochemical performance is of central importance for a successful technical realization of Solid Oxide Fuel Cell (SOFC) systems. The route of electrode fabrication for the SOFC by Wet Powder Spraying (WPS) is presented. Stabilized suspensions of the powder materials for the electrodes were sprayed onto a substrate by employing a spray gun. After drying of the layers, binder removal and sintering are performed in one step. The major advantage of this process is its applicability for a large variety of materials and its flexibility with regard to layer shape and thickness. Above all, flat or curved substrates of any size can be coated, thus opening up the possibility of {open_quotes}up-scaling{close_quotes} SOFC technology. Electrodes with an enhanced electrochemical performance were developed by gradually optimizing the different process steps. For example an optimized SOFC cathode of the composition La{sub 0.65}Sr{sub 0.3}MnO{sub 3} with 40% 8YSZ showed a mean overpotential of about -50 mV at a current density of -0.8 A/cm{sup 2}, with a standard deviation amounting to 16 mV (950{degrees}C, air). Such optimized electrodes can be manufactured with a high degree of reproducibility, as a result of employing a computer-controlled X-Y system for moving the spray gun. Several hundred sintered composites, comprising the substrate anode and the electrolyte, of 100x 100 mm{sup 2} were coated with the cathode by WPS and used for stack integration. The largest manufactured electrodes were 240x240 mm{sup 2}, and data concerning their thickness homogeneity and electrochemical performance are given.

  6. Study on durability for thermal cycle of planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Motoo; Nakata, Kei-ichi; Wakayama, Sin-ichi [Tonen Corp., Saitama (Japan)] [and others

    1996-12-31

    TONEN CORPORATION has developed planar type SOFC since 1986. We demonstrated the output of 1.3 kW in 1991 and 5.1 kW in 1995. Simultaneously we have studied how to raise electric efficiency and reliability utilizing hydrogen and propane as fuel. Durability for thermal cycle is one of the most important problems of planar SOFC to make it more practical. The planar type SOFC is made up of separator, zirconia electrolyte and glass sealant. The thermal expansion of these components are expected to be the same value, however, they still possess small differences. In this situation, a thermal cycle causes a thermal stress due to the difference of the cell components and is often followed by a rupture in cell components, therefore, the analysis of the thermal stress should give us much useful information. The thermal cycle process consists of a heating up and cooling down procedure. Zirconia electrolyte is not bonded to the separator under the condition of the initial heating up procedure, and glass sealant becomes soft or melts and glass seals spaces between the zirconia and separator. The glass sealant becomes harder with the cooling down procedure. Moreover, zirconia is tightly bonded with separator below a temperature which is defined as a constraint temperature and thermal stress also occurs. This indicates that the heating up process relaxes the thermal stress and the cooling down increases it. In this paper, we simulated dependence of the stress on the sealing configuration, thermal expansion of sealant and constraint temperature of sealant glass. Furthermore, we presented SOFC electrical properties after a thermal cycle.

  7. Transient performance of integrated SOFC system including spatial temperature control

    OpenAIRE

    Mueller, F; Fardadi, M; Shaffer, B; Brouwer, J; Jabbari, F

    2010-01-01

    Spatial temperature feedback control has been developed for a simulated integrated non-pressurized simple cycle solid oxide fuel cell (SOFC) system. The fuel cell spatial temperature feedback controller is based on (1) feed-forward set-points that minimize temperature variation in the fuel cell electrode-electrolyte solid temperature profile for the system operating power range, and (2) decentralized proportional-integral based feedback to maintain the fuel cell spatial temperature profile du...

  8. Innovative Seals for Solid Oxide Fuel Cells (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Raj

    2008-06-30

    A functioning SOFC requires different type of seals such as metal-metal, metal-ceramic, and ceramic-ceramic. These seals must function at high temperatures between 600--900{sup o}C and in oxidizing and reducing environments of the fuels and air. Among the different type of seals, the metal-metal seals can be readily fabricated using metal joining, soldering, and brazing techniques. However, the metal-ceramic and ceramic-ceramic seals require significant research and development because the brittle nature of ceramics/glasses can lead to fracture and loss of seal integrity and functionality. Consequently, any seals involving ceramics/glasses require a significant attention and technology development for reliable SOFC operation. This final report is prepared to describe the progress made in the program on the needs, approaches, and performance of high temperature seals for SOFC. In particular, a new concept of self-healing glass seals is pursued for making seals between metal-ceramic material combinations, including some with a significant expansion mismatch.

  9. Continued research, development and test of SOFC Technology. Final report

    Energy Technology Data Exchange (ETDEWEB)

    2008-09-15

    The aim of the project was to further develop the SOFC cell and stack technology and drive down manufacturing costs in order to accomplish the performance and economic targets set forward in the SOFC road map, which has been developed in collaboration with the national Danish SOFC Strategy group. The project was divided into four parts. Part 1, Continued cell development covered the successful development of larger cells with a 500 cm2 footprint. Part 2, Cell manufacturing covered the production of 9.859 equivalents (12x12 cm2 standard cells) that were used in the stacks for demonstration projects (EFP 33033-0050)and for in-house research, development and testing in this project. Part 3, Continued stack development covered the successful test of a 3 kW{sub e} stack as well as the planning of a >8.000 hours stack test with new stack technology. The >8.000 hours test that started after the end date for this project will last for 12 months and be reported in the PSO 2008-1-010049 project. Part 4, Stack manufacturing covered a number of small stacks for in-house research, development and testing. (auther)

  10. Recent activities of SOFC research development and demonstration in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Yokokawa, Harumi [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki (Japan); Tokyo City Univ. (Japan). Advanced Research Labs.

    2010-07-01

    Currently Japanese efforts in developing the SOFC systems have two major targets; one is small SOFC cogeneration systems for residential houses or small business sites, the other being the SOFC-GT hybrid systems with an aim at larger stationary applications. The former activity exhibits impressively rapid progress in system development and demonstration in actual residential environment. On the other hand, the development of hybrid systems is not so rapid but successfully has continued to test the operation of the hybrid system in a 200 kW class. The common requirement for both applications is high durability such as 40,000-100,000 of life. To achieve a long life simultaneously with reasonably low price and high efficiency the NEDO project is going on to promote the cooperation among the stack developers, national institute and universities. To achieve well organized cooperation, it is highly required to create mutual reliance between industry and academic organizations. After several years' experience, progress has been made in maturing cooperation and in leading to many new insights into physicochemical understanding of degradation phenomena. Some of them will be reported. (orig.)

  11. Realisation of an anode supported planar SOFC system

    Energy Technology Data Exchange (ETDEWEB)

    Buchkremer, H.P.; Stoever, D. [Institut fuer Werkstoffe der Energietechnik, Juelich (Germany); Diekmann, U. [Zentralabteilung Technologie, Juelich (Germany)] [and others

    1996-12-31

    Lowering the operating temperature of S0FCs to below 800{degrees}C potentially lowers production costs of a SOFC system because of a less expensive periphery and is able to guarantee sufficient life time of the stack. One way of achieving lower operating temperatures is the development of new high conductive electrolyte materials. The other way, still based on state-of-the-art material, i.e. yttria-stabilized zirconia (YSZ) electrolyte, is the development of a thin film electrolyte concept. In the Forschungszentrum Julich a program was started to produce a supported planar SOFC with an YSZ electrolyte thickness between 10 to 20 put. One of the electrodes, i.e. the anode, was used as support, in order not to increase the number of components in the SOFC. The high electronic conductivity of the anode-cermet allows the use of relatively thick layers without increasing the cell resistance. An additional advantage of the supported planar concept is the possibility to produce single cells larger than 10 x 10 cm x cm, that is with an effective electrode cross area of several hundred cm{sup 2}.

  12. Development of 10kW SOFC module

    Energy Technology Data Exchange (ETDEWEB)

    Hisatome, N.; Nagata, K. [Mitsubishi Heavy Industries, Ltd., Nagasaki (Japan); Kakigami, S. [Electric Power Development Co., Inc., Tokyo (Japan)] [and others

    1996-12-31

    Mitsubishi Heavy industries, Ltd. (MHI) has been developing tubular type Solid Oxide Fuel Cells (SOFC) since 1984. A 1 kW module of SOFC has been continuously operated for 3,000 hours with 2 scheduled thermal cycles at Electric Power Development Co., Inc. (EPDC) Wakamatsu Power Station in 1993. We have obtained of 34% (HHV as H{sub 2}) module efficiency and deterioration rate of 2% Per 1,000 hours in this field test. As for next step, we have developed 10 kW module in 1995. The 10 kW module has been operated for 5,000 hours continuously. This module does not need heating support to maintain the operation temperature, and the module efficiency was 34% (HHV as H{sub 2}). On the other hand, we have started developing the technology of pressurized SOFC. In 1996, pressurized MW module has been tested at MHI Nagasaki Shipyard & Machinery, Works. We are now planning the development of pressurized 10 kW module.

  13. Numerical investigation of a novel burner to combust anode exhaust gases of SOFC stacks

    Directory of Open Access Journals (Sweden)

    Pianko-Oprych Paulina

    2017-09-01

    Full Text Available The aim of the present study was a numerical investigation of the efficiency of the combustion process of a novel concept burner under different operating conditions. The design of the burner was a part of the development process of a complete SOFC based system and a challenging combination of technical requirements to be fulfilled. A Computational Fluid Dynamics model of a non-premixed burner was used to simulate combustion of exhaust gases from the anode region of Solid Oxide Fuel Cell stacks. The species concentrations of the exhaust gases were compared with experimental data and a satisfactory agreement of the conversion of hydrocarbons was obtained. This validates the numerical methodology and also proves applicability of the developed approach that quantitatively characterized the interaction between the exhaust gases and burner geometry for proper combustion modelling. Thus, the proposed CFD approach can be safely used for further numerical optimisation of the burner design.

  14. Development of Robust Metal-Supported SOFCs and Stack Components in EU METSAPP Consortium

    DEFF Research Database (Denmark)

    Sudireddy, Bhaskar Reddy; Nielsen, Jimmi; Persson, Åsa Helen

    2017-01-01

    METSAPP project has been executed with an overall aim of developing advanced metal-supported cells and stacks based on a robust, reliable and up-scalable technology. During the project, oxidation resistant nanostructured anodes based on modified SrTiO3 were developed and integrated into MS...... and best performance and stability combination was observed with doped SrTiO3 based anode designs. Furthermore, numerical models to understand the corrosion behavior of the MS-SOFCs were developed and validated. Finally, the cost effective concept of coated metal interconnects was developed, which resulted...... in 90% reduction in Cr evaporation, three times lower Cr2O3 scale thickness and increased lifetime. The possibility of assembling these cells into two radically different stack designs was demonstrated....

  15. Diesel CPO for SOFC. Development of a cold-flame assisted CPO reactor coupled to a SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Van Dijk, H.A.J.; Ouweltjes, J.P.; Nyqvist, R.G. [ECN Hydrogen and Clean Fossil Fuels, Petten (Netherlands)

    2009-07-15

    Within the research program 'Reforming of liquid fuels for fuel-cells', ECN started a project on the development of a diesel CPO (catalytic partial oxidation) reformer for SOFC (solid oxide fuel cell) in 2005. The application in mind is a small scale (5kWe) diesel fed auxiliary power unit (APU). The goal of the project is to develop the technology required to transform a liquid logistic fuel into a reformat suitable for the operation of a SOFC. The emphasis of this work is on the development of a cold-flame assisted evaporator/mixer coupled to a catalytic CPO reformer. The application of cold-flame evaporation and mixing allows the reformat to be directly fed to the SOFC without further heating or cooling. Moreover, once cold-flames are ignited and stabilized, pre-heating of the air and fuel becomes obsolete. These aspects justify the development described in this report. In the cold-flame evaporator/mixer, the cold-flames are stabilized by means of a recirculation tube. The momentum of the fuel spray of the nozzle induces the required recirculation. The cold flame evaporator/mixer was coupled to a catalytic reformer reactor, transforming the hydrocarbon+air feed into a CO+H2 rich reformate. The reformer was coupled to a SOFC to be able to verify the quality of the reformat obtained with this reformer. The SOFC therefore served as an analysis tool. Characteristically, the reformat was held at 800C all the way towards the SOFC. For this, high temperature flange connections and steel-ceramic expansion connections were successfully applied. It is demonstrated that cold-flame evaporation of liquid fuels is a feasible means of feed preparation for a catalytic reforming reactor. The quality of the resulting reformat is adequate to be fed to the SOFC. The reformat quality, however, decreased with time-on-stream due to fouling of the reformer by carbon-depositions. These carbon-depositions were essentially located on the fuel injector, which is the coldest part

  16. Full Ceramic Fuel Cells Based on Strontium Titanate Anodes, An Approach Towards More Robust SOFCs

    DEFF Research Database (Denmark)

    Holtappels, Peter; Irvine, J.T.S.; Iwanschitz, B.

    2013-01-01

    The persistent problems with Ni-YSZ cermet based SOFCs, with respect to redox stability and tolerance towards sulfur has stimulated the development of a full ceramic cell based on strontium titanate(ST)- based anodes and anode support materials, within the EU FCH JU project SCOTAS-SOFC. Three...

  17. A Zero-Dimensional Model of a 2nd Generation Planar SOFC Using Calibrated Parameters

    DEFF Research Database (Denmark)

    Petersen, Thomas Frank

    2006-01-01

    This paper presents a zero-dimensional mathematical model of a planar 2nd generation co-flow SOFC developed for simulation of power systems. The model accounts for the electrochemical oxidation of hydrogen as well as the methane reforming reaction and the water-gas shift reaction. An important part...... SOFC-based power systems....

  18. Modeling and Analysis of Transport Processes and Efficiency of Combined SOFC and PEMFC Systems

    DEFF Research Database (Denmark)

    Rabbani, Raja Abid; Rokni, Masoud

    2014-01-01

    A hybrid fuel cell system (~10 kWe) for an average family house including heating is proposed. The investigated system comprises a Solid Oxide Fuel Cell (SOFC) on top of a Polymer Electrolyte Fuel Cell (PEFC). Hydrogen produced from the off-gases of the SOFC can be fed directly to the PEFC. Simul...

  19. Improvement of SOFC electrodes using mixed ionic-electronic conductors

    Energy Technology Data Exchange (ETDEWEB)

    Matsuzaki, Y.; Hishinuma, M. [Tokyo Gas Co., Ltd. (Japan)

    1996-12-31

    Since the electrode reaction of SOFC is limited to the proximity of a triple phase boundary (TPB), the local current density at the electrode and electrolyte interface is larger than mean current density, which causes large ohmic and electrode polarization. This paper describes an application of mixed ionic-electronic conductors to reduce such polarization by means of (1) enhancing ionic conductivity of the electrolyte surface layer by coating a high ionic conductors, and (2) reducing the local current density by increasing the electrochemically active sites.

  20. Evaluation of Cathode Air Flow Transients in a SOFC/GT Hybrid System Using Hardware in the Loop Simulation.

    Science.gov (United States)

    Zhou, Nana; Yang, Chen; Tucker, David

    2015-02-01

    Thermal management in the fuel cell component of a direct fired solid oxide fuel cell gas turbine (SOFC/GT) hybrid power system can be improved by effective management and control of the cathode airflow. The disturbances of the cathode airflow were accomplished by diverting air around the fuel cell system through the manipulation of a hot-air bypass valve in open loop experiments, using a hardware-based simulation facility designed and built by the U.S. Department of Energy, National Energy Technology Laboratory (NETL). The dynamic responses of the fuel cell component and hardware component of the hybrid system were studied in this paper.

  1. High-Temperature Desulfurization of Heavy Fuel-Derived Reformate Gas Streams for SOFC Applications

    Science.gov (United States)

    Flytzani-Stephanopoulos, Maria; Surgenor, Angela D.

    2007-01-01

    Desulfurization of the hot reformate gas produced by catalytic partial oxidation or autothermal reforming of heavy fuels, such as JP-8 and jet fuels, is required prior to using the gas in a solid oxide fuel cell (SOFC). Development of suitable sorbent materials involves the identification of sorbents with favorable sulfidation equilibria, good kinetics, and high structural stability and regenerability at the SOFC operating temperatures (650 to 800 C). Over the last two decades, a major barrier to the development of regenerable desulfurization sorbents has been the gradual loss of sorbent performance in cyclic sulfidation and regeneration at such high temperatures. Mixed oxide compositions based on ceria were examined in this work as regenerable sorbents in simulated reformate gas mixtures and temperatures greater than 650 C. Regeneration was carried out with dilute oxygen streams. We have shown that under oxidative regeneration conditions, high regeneration space velocities (greater than 80,000 h(sup -1)) can be used to suppress sulfate formation and shorten the total time required for sorbent regeneration. A major finding of this work is that the surface of ceria and lanthanan sorbents can be sulfided and regenerated completely, independent of the underlying bulk sorbent. This is due to reversible adsorption of H2S on the surface of these sorbents even at temperatures as high as 800 C. La-rich cerium oxide formulations are excellent for application to regenerative H2S removal from reformate gas streams at 650 to 800 C. These results create new opportunities for compact sorber/regenerator reactor designs to meet the requirements of solid oxide fuel cell systems at any scale.

  2. Tracking Oxygen Vacancies in Thin Film SOFC Cathodes

    Science.gov (United States)

    Leonard, Donovan; Kumar, Amit; Jesse, Stephen; Kalinin, Sergei; Shao-Horn, Yang; Crumlin, Ethan; Mutoro, Eva; Biegalski, Michael; Christen, Hans; Pennycook, Stephen; Borisevich, Albina

    2011-03-01

    Oxygen vacancies have been proposed to control the rate of the oxygen reduction reaction and ionic transport in complex oxides used as solid oxide fuel cell (SOFC) cathodes [1,2]. In this study oxygen vacancies were tracked, both dynamically and statically, with the combined use of scanned probe microscopy (SPM) and scanning transmission electron microscopy (STEM). Epitaxial films of La 0.8 Sr 0.2 Co O3 (L SC113) and L SC113 / LaSrCo O4 (L SC214) on a GDC/YSZ substrate were studied, where the latter showed increased electrocatalytic activity at moderate temperature. At atomic resolution, high angle annular dark field STEM micrographs revealed vacancy ordering in L SC113 as evidenced by lattice parameter modulation and EELS studies. The evolution of oxygen vacancy concentration and ordering with applied bias and the effects of bias cycling on the SOFC cathode performance will be discussed. Research is sponsored by the of Materials Sciences and Engineering Division, U.S. DOE.

  3. Parametric exergy analysis of a tubular Solid Oxide Fuel Cell (SOFC) stack through finite-volume model

    International Nuclear Information System (INIS)

    Calise, F.; Ferruzzi, G.; Vanoli, L.

    2009-01-01

    This paper presents a very detailed local exergy analysis of a tubular Solid Oxide Fuel Cell (SOFC) stack. In particular, a complete parametric analysis has been carried out, in order to assess the effects of the synthesis/design parameters on the local irreversibilities in the components of the stack. A finite-volume axial-symmetric model of the tubular internal reforming Solid Oxide Fuel Cell stack under investigation has been used. The stack consists of: SOFC tubes, tube-in-tube pre-reformer and tube and shell catalytic burner. The model takes into account the effects of heat/mass transfer and chemical/electrochemical reactions. The model allows one to predict the performance of a SOFC stack once a series of design and operative parameters are fixed, but also to investigate the source and localization of inefficiency. To this scope, an exergy analysis was implemented. The SOFC tube, the pre-reformer and the catalytic burner are discretized along their longitudinal axes. Detailed models of the kinetics of the reforming, catalytic combustion and electrochemical reactions are implemented. Pressure drops, convection heat transfer and overvoltages are calculated on the basis of the work previously developed by the authors. The heat transfer model includes the contribution of thermal radiation, so improving the models previously used by the authors. Radiative heat transfer is calculated on the basis of the slice-to-slice configuration factors and corresponding radiosities. On the basis of this thermochemical model, an exergy analysis has been carried out, in order to localize the sources and the magnitude of irreversibilities along the components of the stack. In addition, the main synthesis/design variables were varied in order to assess their effect on the exergy destruction within the component to which the parameter directly refers ('endogenous' contribution) and on the exergy destruction of all remaining components ('exogenous' contribution). Then, this analysis

  4. Manufacturing of Electrolyte and Cathode Layers SOFC Using Atmospheric Spraying Method and Its Characterization

    Directory of Open Access Journals (Sweden)

    S. Sulistyo

    2012-12-01

    Full Text Available The use of Solid Oxide Fuel Cell (SOFC has created various interest in many parties, due to its capability to convert gases into electricity. The main requirement of SOFC cell components is to be produced as thin as possible to minimize the losses of electrical resistance, as well as able to support internal and external loads. This paper discusses the procedure of making a thin electrolyte layer, as well as a porous thin layer cathode using atmospheric spraying technique. The procedure of spraying was in room temperature with the process of sintering at temperature of 13500 C held for 3 hours. The SOFC characterization of electrolyte and cathode microstructure was determined by using the SEM, FESEM, XRD and impedance spectroscopy, to measure the impedance of SOFC cells. The results show that the thickness of thin layer electrolyte and porous cathode obtained of about 20 µm and 4 µm, respectively. Also the SOFC cell impedance was measured of 2.3726 x 106 Ω at room temperature. The finding also demonstrated that although the materials (anode, cathode and electrolyte possess different coefficient thermal expansion, there was no evidence of flaking layers which seen the materials remain intact. Thus, the atmospheric spraying method can offer an alternative method to manufacturing of SOFC thin layer electrolyte and cathode. [Key words: SOFC; spraying method; electrolyte; cathode

  5. Municipal Solid Waste Gasification Plant Integrated With SOFC and Gas Turbine

    DEFF Research Database (Denmark)

    Bellomare, Filippo; Rokni, Masoud

    2012-01-01

    An interesting source of producing energy with low pollutants emission and reduced environmental impact are the biomasses; particularly using Municipal Solid Waste (MSW) as fuel, can be a competitive solution not only to produce energy with negligible costs but also to decrease the storage...... in landfills. A Municipal Solid Waste Gasification Plant Integrated with Solid Oxide Fuel Cell (SOFC) and Gas Turbine (GT) has been studied and the plant is called IGSG (Integrated Gasification SOFC and GT). Gasification plant is fed by MSW to produce syngas by which the anode side of a SOFC is fed wherein...

  6. Oxidation behavior of a Ni-Fe support in SOFC anode atmosphere

    DEFF Research Database (Denmark)

    Xu, Na; Chen, Ming; Han, Minfang

    2018-01-01

    In this work, we investigated the long-term oxidation behavior of a Ni-Fe (1:1 weight ratio) support for solid oxide fuel cell (SOFC) applications. Ni-Fe supports were obtained through tape casting, high temperature sintering and pre-reducing in 97% H2/N2 (9/91)-3% H2O at 750 and 1000 °C, respect...... annealed in the two atmospheres maintained sufficiently high conductivity. The results from the current work demonstrate that the porous Ni-Fe support can be well employed in SOFCs, especially metal-supported SOFCs....

  7. Development of an autonomous transportable SOFC system operating on C-based fuel. The lilith system; Development of an autonomous transportable SOFC system operating on C-based fuel. The lilith system. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Bucheli, O; Ihringer, R; Diethelm, S

    2006-07-01

    The aim of the project is to adapt a prototype portable SOFC system to the requirements of demonstrator for educational institutions as niche market. This involves on the one hand stable operation of the unit with reformed fuels, on the other hand the integration and control of auxiliaries such as fan and visualization. The result is aimed to be a practical communication vector, letting people touch SOFC technology. As intended, 2 redesigned systems have been realised and mounted. While design simplification allowed an easier construction of the units, more technical challenges than anticipated were encountered on the level of thermal management. The re-designed thermal system did not improve the thermal management to the level expected. Heat transfer to the stack chamber was on the lower limit, leading to rather high exhaust temperatures and also affected stack performance and robustness. Reforming of methanol worked to satisfaction on the short term, long-term data have not been obtained to date. Electronic controls, visualisation and auxiliaries have been elaborated based on the given specifications, but could not be validated on the complete system within the project time-frame. After a major personnel change within HTceramix, it is intended to pursue the activity next year with a new team. (author)

  8. Effect of additives in the baking of electrolytic materials for SOFC; SOFC yo denkaishitsu zairyo no shoseiji ni okeru tenkabutsu no koka

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, H. [Kansai Electric Power Co. Inc., Osaka (Japan)

    1998-09-10

    A technique is discovered for improving on the baking properties of cerium oxide which is one of the solid electrolytic materials for SOFC (solid oxide fuel cell). Cerium oxide, samarium oxide, and gallium oxide are weighed, each to the specified element ratio. The element ratio of cerium is fixed at 0.8 against the other elements except oxygen, and the element ratios of samarium or gallium are caused to change. Specimens containing gallium are designated as CSGa, those not containing as SDC. SDC baked at 1600degC and CSGa (1%) baked at 1450degC are similar to each other in terms of average grain diameter. Specimens with gallium added thereto can be baked at temperatures that are lower than these by approximately 150degC. The conductivity of CSGa (0.2%) baked at 1500degC is higher than that of SDC baked at the same temperature, and is similar to that of SDC baked at 1600degC. Baking is enhanced by the addition of 0.2% gallium. In the domain where more than 1% of gallium is in presence, conductivity lowers with an increase in the amount of gallium added. The conductivity of CSGa (1%) baked at 1450degC is similar to that of SDC baked at 1600degC. 4 figs., 1 tab.

  9. Transport parameters of thin, supported cathode layers in solid oxide fuel cells (SOFCs); Transportparameter duenner, getraegerter Kathodenschichten der oxidkeramischen Brennstoffzelle

    Energy Technology Data Exchange (ETDEWEB)

    Wedershoven, Christian

    2010-12-22

    The aim of this work was to determine the transport properties of thin cathode layers, which are part of the composite layer of a fabricated anode-supported solid oxide fuel cell (SOFC). The transport properties of the anode and cathode have a significant influence on the electrochemical performance of a fuel cell stack and therefore represent an important parameter when designing fuel cell stacks. In order to determine the transport parameters of the cathode layers in a fabricated SOFC, it is necessary to permeate the thin cathode layer deposited on the gas-tight electrolyte with a defined gas transport. These thin cathode layers cannot be fabricated as mechanically stable single layers and cannot therefore be investigated in the diffusion and permeation experiments usually used to determine transport parameters. The setup of these experiments - particularly the sample holder - was therefore altered in this work. The result of this altered setup was a three-dimensional flow configuration. Compared to the conventional setup, it was no longer possible to describe the gas transport in the experiments with an analytical one-dimensional solution. A numerical solution process had to be used to evaluate the measurements. The new setup permitted a sufficiently symmetrical gas distribution and thus allowed the description of the transport to be reduced to a two-dimensional description, which significantly reduced the computational effort required to evaluate the measurements. For pressure-induced transport, a parametrized coherent expression of transport could be derived. This expression is equivalent to the analytical description of the transport in conventional measurement setups, with the exception of parameters that describe the geometry of the gas diffusion. In this case, a numerical process is not necessary for the evaluation. Using the transport parameters of mechanically stable anode substrates, which can be measured both in the old and the new setups, the old and

  10. Development of an integrated system for a SOFC for combined heat and power generation; Entwicklung eines integrierten Systems fuer eine SOFC mit Kraft-Waerme-Stoffkopplung

    Energy Technology Data Exchange (ETDEWEB)

    Stichtenoth, J.; Meyer-Pittroff, R.

    2002-06-01

    The feasibility of CO2 removal from the exhaust of a 250 kW{sub e} SOFC module, with recirculation of the liquefied CO2 is discussed for the example of a German brewery (Bayerische Staatsbrauerei Weihenstephan). An electric efficiency of 50% can be achieved provided that the liquefied CO2 is utilized to substitute CO2 liquefaction in another point of the process. The high-temperature waste heat of the 250 kW SOFC is fed into the brewer's copper via feedwater preheating. [German] In dieser Studie werden die Moeglichkeiten einer technischen Rueckgewinnung von CO{sub 2} aus dem Abgasstrom eines SOFC-Moduls mit 250 kW elektrischer Leistung und Rueckfuehrung des verfluessigten CO{sub 2} in den Wertschoepfungsprozess am Beispiel der Bayerischen Staatsbrauerei Weihenstephan untersucht. Unter der Voraussetzung, dass dieses verfluessigte CO{sub 2} als Produkt Verwendung findet und die CO{sub 2}-Verfluessigung an anderer Stelle substituiert, kann der von der SOFC gelieferte Energiebeitrag zur CO{sub 2}-Verfluessigung dem Gesamtsystem gutgeschrieben werden, so dass der elektrische Wirkungsgrad bei 50% bleibt. Die Hochtemperaturabwaerme der 250 kW-SOFC wird ueber eine Speisewasservorwaermung in den Dampfkessel der Brauerei eingekoppelt.

  11. Power generation characteristics of tubular type SOFC by wet process

    Energy Technology Data Exchange (ETDEWEB)

    Tajiri, H.; Nakayama, T. [Kyushu Electric Power Company, Inc., Fukuoka (Japan); Kuroishi, M. [TOTO Ltd., Kanagawa (Japan)] [and others

    1996-12-31

    The development of a practical solid oxide fuel cell requires improvement of a cell performance and a cell manufacturing technology suitable for the mass production. In particular tubular type SOFC is thought to be superior in its reliability because its configuration can avoid the high temperature sealing and reduce the thermal stress resulting from the contact between cells. The authors have fabricated a tubular cell with an air electrode support by a wet processing technique, which is suitable for mass production in improving a power density. To enhance the power output of the module, the Integrated Tubular-Type (ITT) cell has been developed. This paper reports the performance of the single cells with various active anode areas and the bundle with series-connected 9-ITT cells with an active anode area of 840 cm{sup 2}.

  12. Fabrication and characteristics of unit cell for SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gwi-Yeol; Eom, Seung-Wook; Moon, Seong-In [Korea Electrotechnology Research Institute, Kyongnam (Korea, Republic of)] [and others

    1996-12-31

    Research and development on solid oxide fuel cells in Korea have been mainly focused on unit cell and small stack. Fuel cell system is called clean generation system which not cause NOx or SOx. It is generation efficiency come to 50-60% in contrast to 40% of combustion generation system. Among the fuel cell system, solid oxide fuel cell is constructed of ceramics, so stack construction is simple, power density is very high, and there are no corrosion problems. The object of this study is to develop various composing material for SOFC generation system, and to test unit cell performance manufactured. So we try to present a guidance for developing mass power generation system. We concentrated on development of manufacturing process for cathode, anode and electrolyte.

  13. Development of planar SOE/SOFC reversible cell

    International Nuclear Information System (INIS)

    Kusunoki, A.; Matsubara, H.; Kikuoka, Y.; Yanagi, C.; Kugimiya, K.; Yoshino, M.; Tokura, M.; Watanabe, K.; Ueda, S.; Sumi, M.; Miyamoto, H.; Tokunaga, S.

    1993-01-01

    A new energy storage system using SOE/SOFC (solid oxide electrolysis-solid oxide fuel cells) reversible cells is presented, where a unit cell works as a fuel cell during a period of high electric power demand and alternately works as an electrolysis cell during a period of low power demand. A planar cell configuration is used which allows for a compact and low cost energy storage and load leveling system for power stations. Tests were performed to verify the reversibility of the planar cell, at 1000 deg C, with YSZ (Yttria stabilized zirconia) as the solid electrolyte, to improve the cell performance by reducing the overvoltage in electrolysis, and to obtain fundamental characteristics of a reversible cell. 3 figs

  14. Overview of SOFC/SOEC development at DTU Energy Conversion

    DEFF Research Database (Denmark)

    Hagen, Anke

    2014-01-01

    According to a broad political agreement in Denmark, the Danish energy system should become independent on fossil fuels like oil, coal and natural gas by the year 2050. This aim requires expansion of electricity production from renewable sources, in particular wind mills. In order to balance...... the fluctuating power production and to cope with the discrepancies between demand and supply of power, solid oxide fuel cells and electrolysis are considered key technologies. DTU Energy Conversion has a strong record in SOFC/SOEC research, with a close collaboration with industry, in particular with Danish...... Topsoe Fuel Cell A/S. Recent achievements will be presented ranging from development of new cell generations, manufacturability, up to testing under realistic operating conditions including degradation studies and high pressure testing. A strong focus will be on development of methodologies, e...

  15. Development of innovative metal-supported IT-SOFC technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    The results of tests on a solid oxide fuel cell developed by Ceres Power Ltd are reported. The fabrication and construction of the thick film ceramic fuel cell on porous stainless steel substrate is described. Tests were conducted under constant load and under recycling. In stack development, the cells were interconnected by laser-welding the steel substrates to the plates. Possible concepts for an IT-SOFC based on a small CHP system were evaluated by computer modelling. The performance levels of the cell at various temperatures, and the cost estimates, are given as evidence of suitability for development towards commercialisation. The study was conducted as part of a UK DTI programme on New and Renewable Energy Sources.

  16. Frictional forces in an SOFC stack with sliding seals

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, T; Oishi, N; Namikawa, T; Yamazaki, Y [Tokyo Institute of Technology, Tokyo (Japan)

    1996-06-05

    The detrimental thermal stresses in planar SOFC stacks can be reduced using sliding seals. In the proposal planar stack the electrolyte film is sandwiched by YSZ support rings to release the thermal stresses. In order to estimate the strength of the support ring, the frictional forces between heat resistant alloy and YSZ were measured at 900{degree}C. The coefficient of friction between Hastelloy X and YSZ increased when they were measured lifter 144h heating. However, the coefficient of friction between HA-214 and YSZ did not increase. The measurement and a calculation of the stresses in the support rings led the result that a thickness of 0.6mm was necessary for 200mm diameter support rings under a stack pressure of 0.1kgcm{sup -2}. 6 refs., 9 figs., 1 tab.

  17. Relaxation of stresses during reduction of anode supported SOFCs

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Chatzichristodoulou, Christodoulos; Jørgensen, Peter Stanley

    2016-01-01

    To assess the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. This work reports further details on a newly discovered creep phenomenon......, accelerated creep, taking place during the reduction of a Ni-YSZ anode. This relaxes stresses at a much higher rate (~×104) than creep during operation. Thus, the phenomenon of accelerated creep during reduction has to be considered both in the production of stacks and in the analysis of the stress field...... of reduction should decrease significantly over minutes. In this work these internal stresses are measured in-situ before and after the reduction by use of X-ray diffraction. This is done by determining the elastic micro-strains (correlating to the stresses), which are assessed from the widening of the Bragg...

  18. Description of SOFC anode behavior by a mathematical modelling procedure

    International Nuclear Information System (INIS)

    Ielo, I.; Maggio, G.; Antonucci, V.; Giordano, N.

    1993-01-01

    One of the principal objectives in the development of SOFC is the identification of a stable Ni-cermet anode material with low polarization at high current density. In this respect, a mathematical approach, based on theoretical considerations, has been made in order to identify the optimal combination of geometrical and morphological characteristics of the system. The two limiting cases of diffusion-controlled and kinetic-controlled mechanisms are taken into account. Results in terms of limiting current have been treated by substituting into the related equations morphological parameters (surface area and pore size distribution of the support, metal content and surface area, electrode film thickness). Results are compared to existing experimental data and the influence of various parameters on the overall anode performance is evaluated. 2 tabs., 24 refs

  19. Avances en el desarrollo de interconectores metálicos de celdas SOFC

    Directory of Open Access Journals (Sweden)

    Alvarado-Flores, J.

    2013-08-01

    Full Text Available Interest in solid oxide fuel cells (SOFC stems from their higher efficiencies and lower levels of emitted pollutants, compared to traditional power production methods. Interconnects are a critical part in SOFC stacks, which connect cells in series electrically, and also separate air or oxygen at the cathode side from fuel at the anode side. Therefore, the requirements of interconnects are the most demanding, i.e., to maintain high electrical conductivity, good stability in both reducing and oxidizing atmospheres, and close thermal expansion coefficient (TEC match and good compatibility with other SOFC ceramic components. This paper reviewed the interconnect materials, and coatings for metallic interconnect materials in a SOFC cell.El interés en las celdas de combustible de óxido sólido (SOFC, se deriva de su alta eficiencia y la capacidad de tener un bajo nivel de emisiones contaminantes, en comparación con los métodos tradicionales de producción de energía. Los interconectores, son parte crítica del ordenamiento de una celda SOFC, debido a que conecta en serie las celdas y además, separa el aire u oxígeno (cátodo del combustible (ánodo. Por lo tanto, los requisitos del interconector son muy exigentes, por ejemplo, es necesario mantener conductividad eléctrica elevada, óptima estabilidad tanto en atmósferas reductoras como oxidantes y el coeficiente de expansión térmica (TEC, debe ser compatible con los otros componentes cerámicos de la celda SOFC. Este artículo, revisa los materiales de interconexión, y materiales de revestimiento para interconectores metálicos en una celda SOFC.

  20. Thermodynamic modeling of the power plant based on the SOFC with internal steam reforming of methane

    International Nuclear Information System (INIS)

    Ivanov, Peter

    2007-01-01

    Mathematical model based on the thermodynamic modeling of gaseous mixtures is developed for SOFC with internal steam reforming of methane. Macroscopic porous-electrode theory, including non-linear kinetics and gas-phase diffusion, is used to calculate the reforming reaction and the concentration polarization. Provided the data concerning properties and costs of materials the model is fit for wide range of parametric analysis of thermodynamic cycles including SOFC

  1. Development of solid oxide fuel cells (SOFC); Desenvolvimento de celulas a combustivel do tipo oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Souza, F.M.B. de; Carvalho, L.F.V. de; Alencar, M.G de; Boaventura, J.S. [Universidade Federal da Bahia (DFQ/UFBA), Salvador, BA (Brazil). Dept de Fisico-Quimica. Grupo de energia e Ciencias dos Materiais], e-mail: bventura@ufba.br

    2008-07-01

    The most promising technology for generating electric power, with reduced environmental impact, is the fuel cell. This technology is virtually non-polluting and the fuel supplies can be renewable. Therefore is necessary to study the technique of preparing the entire anode / electrolyte / cathode to optimize its operation. There are still major challenges to making the SOFC economically viable. The key is the improvement of manufacturing of its components and use of materials that can simultaneously reduce costs and reduce the temperature of operation. Among the properties of the cell, was shown the dependence of the efficiency of the device on the properties of the electrolyte, particularly its thickness. The mixture of YSZ with GDC in the composition of the anode and electrolyte aims to obtain a material with greater ionic conductivity. After sintering the cell was characterized by scanning electron microscopy (SEM). (author)

  2. Fabricación de soportes anódicos metálicos para SOFC por vía pulvimetalúrgica

    Directory of Open Access Journals (Sweden)

    Arahuetes, E.

    2008-10-01

    Full Text Available The commercialization of environmentally-friendly power production technologies as solid oxide fuel cells (SOFC implies the cost reduction of the materials initially used in their design. The employment of a porous metallic support that significantly reduces the amount of active ceramic material is an interesting option. In this work, the processing of four different alloys (two Fe-based and two Ni-based is evaluated for their possible use as porous metallic supports in SOFC. A binder system is proposed that, mixed with big-sized metallic powders, allows to obtain materials with the required porosity level (≥ 30%. Moreover, a stage of grinding prior to compaction of mixes binder-metallic powder allows the manufacturing of dimensionally stable components during binder removal, even although their high porosity.

    La comercialización de tecnologías de producción de energía medioambientalmente respetuosas, como las pilas de óxido sólido (SOFC, implica el abaratamiento de los materiales con que han sido, inicialmente, diseñadas. El empleo de un soporte metálico poroso que reduzca significativamente la cantidad de material cerámico activo es una opción muy interesante. En este trabajo se estudia el procesado de 4 aleaciones diferentes (dos base Fe y dos base Ni para su posible utilización como soportes metálicos porosos en SOFC. Se propone un sistema ligante que, mezclado con polvos metálicos de gran tamaño, permita obtener materiales con el nivel de porosidad requerida (≥ 30 %. Además, la realización de una etapa de granulado previa a la compactación de las mezclas de polvo metálico permite fabricar piezas que mantienen, pese a su elevada porosidad, la estabilidad dimensional durante el proceso de eliminación del ligante.

  3. On the nanostructuring and catalytic promotion of intermediate temperature solid oxide fuel cell (IT-SOFC) cathodes

    Science.gov (United States)

    Serra, José M.; Buchkremer, Hans-Peter

    Solid oxide fuel cells (SOFCs) are highly efficient energy converters for both stationary and mobile purposes. However, their market introduction still demands the reduction of manufacture costs and one possible way to reach this goal is the decrease of the operating temperatures, which entails the improvement of the cathode electrocatalytic properties. An ideal cathode material may have mixed ionic and electronic conductivity as well as proper catalytic properties. Nanostructuring and catalytic promotion of mixed conducting perovskites (e.g. La 0.58Sr 0.4Fe 0.8Co 0.2O 3- δ) seem to be promising approaches to overcoming cathode polarization problems and are briefly illustrated here. The preparation of nanostructured cathodes with relatively high surface area and enough thermal stability enables to improve the oxygen exchange rate and therefore the overall SOFC performance. A similar effect was obtained by catalytic promoting the perovskite surface, allowing decoupling the catalytic and ionic-transport properties in the cathode design. Noble metal incorporation may improve the reversibility of the reduction cycles involved in the oxygen reduction. Under the cathode oxidizing conditions, Pd seems to be partially dissolved in the perovskite structure and as a result very well dispersed.

  4. CFD analysis of a symmetrical planar SOFC with heterogeneous electrode properties

    International Nuclear Information System (INIS)

    Shi Junxiang; Xue Xingjian

    2010-01-01

    A comprehensive 2-D CFD model is developed to investigate bi-electrode supported cell (BSC) performance. The model takes into account the coupled complex transport phenomena of mass/heat transfer, charge (electron/ion) transport, and electrochemical reactions. The uniqueness of this modeling work is that heterogeneous electrode properties are taken into account, which includes not only linear functionally graded porosity distribution but also various nonlinear distributions in a general sense according to porous electrode features in BSC design. Extensive numerical analysis is performed to elucidate various heterogeneous porous electrode property effects on cell performance. Results indicate that cell performance is strongly dependent on porous microstructure distributions of electrodes. Among the various porosity distributions, inverse parabolic porosity distribution shows promising effects on cell performance. For a given porosity distribution of electrodes, cell performance is also dependent on operating conditions, typically fuel/gas pressure losses across the electrodes. The mathematical model developed in this paper can be utilized for high performance BSC SOFC design and optimization.

  5. Studies on Perovskite-Based Electrodes for Symmetrical SOFCs

    Directory of Open Access Journals (Sweden)

    Dos Santos García, A. J.

    2008-10-01

    Full Text Available The use of the same material as anode and cathode in symmetrical solid oxide fuel cells (SFCs promises notable benefits as easier fabrication, hence lower cost production and resistance to carbon formation upon fuel cracking. Although chromites and chromo-manganites have been proposed as candidate electrode materials for this novel SOFC configuration, demonstrating promising performances, further work is required to develop compositions exhibiting higher efficiencies. In the present work we evaluate the structural evolution from cubic to orthorhombic unit cells with increasing the Fe content and the performance of La4Sr8Ti12-xFexO38-δ (LSTF phases and compare their response with other symmetrical electrodes. The electrochemical performance is 20% higher when using graded LSTF electrodes than in other perovskite-based systems.

    La utilización simultánea de un mismo material cerámico como ánodo y cátodo en pilas de combustible de óxido sólido simétricas (SFCs aporta una serie de beneficios entre los que figura una fabricación más sencilla, reducción de los costes de producción, así como resistencia a la formación de depósitos de carbón por craqueo del combustible. Recientemente, cromitas y cromomanganitas han sido propuestos como materiales capaces de adoptar esta novedosa configuración SOFC y, si bien los resultados obtenidos son prometedores, se requiere de una mayor investigación para el desarrollo de nuevas composiciones que presenten eficiencias más elevadas. En el presente trabajo, se evalúan la evolución de la estructura desde celdas cúbicas a ortorrómbicas al aumentar el contenido en Fe y las prestaciones del sistema La4Sr8Ti12-xFexO38-δ (LSTF y se compara su respuesta con otros electrodos simétricos, observándose que el rendimiento es hasta un 20% mayor en el caso de emplear electrodos LSTF que en

  6. Mesoporous zirconia-ceria for anodes of SOFC and catalyzer

    Energy Technology Data Exchange (ETDEWEB)

    Fantini, Marcia Carvalho de Abreu; Cassimiro, Vinicius Roberto de Sylos; Monteiro, Rafael Cartoni, E-mail: mfantini@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica

    2016-07-01

    Full text: The ceria (CeO{sub 2}) and zirconia (ZrO{sub 2}) based materials are present in several technological applications, mainly as Solid Oxide Fuel Cells (SOFC) anodes and catalysts, for hydrogen production and automotive converter (Three-Way Catalysis). The solid solution Zr{sub x}Ce{sub 1-x}O{sub 2-δ} has attracted special attention, since it shows better thermal stability and higher oxygen storage capacity (OSC), if compared to the non-doped oxides. The mesoporous materials (pores of 2 to 50 nm) show high surface area and gas permeability, important properties for SOFCs and catalysts efficiency. In this work, mesoporous ceria-zirconia (Zr{sub 0.1}Ce{sub 0.9}O{sub 2-δ}) was synthesized by a sol-gel route using inorganic chlorides (ZrCl{sub 4} e CeCl{sub 3.7}H{sub 2}O) as precursors, block copolymer P123 (PEO{sub 20}PPO{sub 70}PEO{sub 20}) as template and TIPB (triisopropyl- benzene) as swelling agent. The solution was submitted to hydrothermal treatment for 48h at 80°C and calcined at 400°C to remove the template, resulting in the crystallized oxide. The characterization was performed by X-ray diffraction at high angles (XRD), small angle X-ray scattering (SAXS), nitrogen adsorption isotherms (NAI) and transmission and scanning electron microscopy (TEM and SEM). The results showed that the material has high surface area (≈ 110 m{sup 2}g{sup -1}), a wide pore size distribution with mean values around 30 nm, predominant cubic phase Fm3m and, in less quantity, tetragonal P4{sub 2}/nmc. The micrographs revealed that the oxide is totally nano-crystallized, having pores with slit shape and a secondary smaller mesoporosity with a narrow size distribution. The amount of P123 in the synthesis was also varied in order to produce pores with different shapes. Four samples were produced with different TIPB/P123 mass rate (0, 1, 2, 4), therefore was possible to verify the pore size expansion due to the swelling addition. The structural and morphological properties

  7. Measurement of residual stresses in deposited films of SOFC component materials

    Energy Technology Data Exchange (ETDEWEB)

    Kato, T.; Momma, A.; Nagata, S.; Kasuga, Y. [Electrotechnical Lab., Ibaraki (Japan)

    1996-12-31

    The stress induced in Solid oxide fuel cells (SOFC)s has important influence on the lifetime of SOFC. But the data on stress in SOFC and mechanical properties of SOW component materials have not been accumulated enough to manufacture SOFC. Especially, the data of La{sub 1-x}Sr{sub x}MnO{sub 3} cathode and La{sub 1-x}Sr{sub x}CrO{sub 3} interconnection have been extremely limited. We have estimated numerically the dependences of residual stress in SOFC on the material properties, the cell structure and the fabrication temperatures of the components, but these unknown factors have caused obstruction to simulate the accurate behavior of residual stress. Therefore, the residual stresses in deposited La{sub 1-x}Sr{sub x}MnO{sub 3} and La{sub 1-x}Sr{sub x}CrO{sub 3} films are researched by the observation of the bending behavior of the substrate strips. The films of SOFC component materials were prepared by the RF sputtering method, because: (1) It can fabricate dense films of poor sinterable material such as La{sub 1-x}Sr{sub x}CrO{sub 3} compared with sintering or plasma spray method. (2) For the complicated material such as perovskite materials, the difference between the composition of a film and that of a target material is generally small. (3) It can fabricate a thick ceramics film by improving of the deposition rate. For example, Al{sub 2}O{sub 3} thick films of 50{mu}m can be fabricated with the deposition rate of approximately 5{mu}m/h industrially. In this paper, the dependence of residual stress on the deposition conditions is defined and mechanical properties of these materials are estimated from the results of the experiments.

  8. Capability of a SOFC-APU to optimise the fuel consumption of motor vehicles; Potenzial einer SOFC-APU bei der Verbrauchsoptimierung von Kraftfahrzeugen

    Energy Technology Data Exchange (ETDEWEB)

    Diegelmann, Christian B.

    2008-04-28

    While the energy system motor vehicle is analysed in this work different application possibilities of a SOFC-Auxiliary Power Unit for reducing the fuel consumption are identified. Apart from the pure electric power supply the APU can support functions like the engine-stop automatism or electric driving (hybrid vehicle). In addition the SOFC-APU generates waste heat at a high temperature level. The waste heat can be used for heating the passenger cabin or for preheating the combustion engine. Several methods are used for evaluating the conservation potentials. A simple estimate of the fuel consumption by means of medium efficiency and power already suffices to identify and evaluate the major impacts. The conservation potential of a SOFC-APU mainly depends on three factors, the start-up consumption of the APU, the operating period and the required electric power. A cold APU must first be heated-up to an operational temperature between 700 and 800 degrees Celsius. The heat-up process requires energy resulting in an excess consumption first. This excess consumption will only be compensated by the high efficiency of the SOFC-APU after a longer operating period. The operating period strongly depends on the electric power. In case of higher electric power the APU achieves a higher conservation rate. An APU is particularly interesting in standard applications with high energy demand. The APU avoids an operation of the combustion engine in the extreme underload range. In case of an air-conditioning at idling speed lasting for 30 minutes a fuel conservation of approx. 36% can be achieved including the start-up consumption. Conservation potentials in fuel consumption can only be achieved in the driving mode if the APU is operational and in case of a longer operating period. The difference in consumption compared to vehicles without APU was determined at vehicles with different basic operating strategies (current vehicle, vehicle with engine-stop automatism, vehicle with

  9. Discrete modelling of the electrochemical performance of SOFC electrodes

    International Nuclear Information System (INIS)

    Schneider, L.C.R.; Martin, C.L.; Bultel, Y.; Bouvard, D.; Siebert, E.

    2006-01-01

    The composite anode and cathode of solid oxide fuel cells (SOFC) are modelled as sintered mixtures of electrolyte and electrocatalyst particles. A particle packing is first created numerically by the discrete element method (DEM) from a loose packing of 40 000 spherical, monosized, homogeneously mixed, and randomly positioned particles. Once the microstructure is sintered numerically, the effective electrode conductivity is determined by discretization of the particle packing into a resistance network. Each particle contact is characteristic of a bond resistance that depends on contact geometry and particle properties. The network, which typically consists of 120 000 bond resistances in total, is solved using Kirchhoff's current law. Distributions of local current densities and particle potentials are then performed. We investigate how electrode performance depends on parameters such as electrode composition, thickness, density and intrinsic material conductivities that are temperature dependent. The simulations show that the best electrode performance is obtained for compositions close to the percolation threshold of the electronic conductor. Depending on particle conductivities, the electrode performance is a function of its thickness. Additionally, DEM simulations generate useful microstructural information such as: coordination numbers, triple phase boundary length and percolation thresholds

  10. High Performance Fe-Co Based SOFC Cathodes

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent; Hansen, Karin Vels; Mogensen, Mogens Bjerg

    2010-01-01

    With the aim of reducing the temperature of the solid oxide fuel cell (SOFC), a new high-performance perovskite cathode has been developed. An area-specific resistance (ASR) as low as 0.12 Ωcm2 at 600 °C was measured by electrochemical impedance spectroscopy (EIS) on symmetrical cells. The cathode...... is a composite between (Gd0.6Sr0.4)0.99Fe0.8Co0.2O3-δ (GSFC) and Ce0.9Gd0.1O1.95 (CGO10). Examination of the microstructure of the cathodes by scanning electron microscopy (SEM) revealed a possibility of further optimisation of the microstructure in order to increase the performance of the cathodes. It also...... seems that an adjustment of the sintering temperature will make a lowering of the ASR value possible. The cathodes were compatible with ceria-based electrolytes but reacted to some extent with zirconia-based electrolytes depending on the sintering temperature....

  11. Lanthanum germanate-based apatites as electrolyte for SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D.; Diaz-Carrasco, P.; Ramos-Barrado, J.R. [Departamento de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C. [Departamento de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain)

    2011-02-15

    Germanate apatites with composition La{sub 10-x}Ge{sub 5.5}Al{sub 0.5}O{sub 26.75-3x/2} have been evaluated for the first time as possible electrolytes for solid oxide fuel cells (SOFCs). Different electrode materials have been considered in this study, i.e. manganite, ferrite, nickelates and cobaltite as cathode materials; and NiO-CGO composite and chromium-manganite as anodes. The chemical compatibility and electrochemical performance of these electrodes with La{sub 9.8}Ge{sub 5.5}Al{sub 0.5}O{sub 26.45} have been studied by X-ray powder diffraction (XRPD) and impedance spectroscopy. The XRPD analysis did not reveal appreciable bulk reactivity with the formation of reaction products between the germanate electrolyte and these electrodes up to 1,200 C. However, a significant cation interdiffusion was observed by energy dispersive spectroscopy (EDS) at the electrode/electrolyte interface, which leads to a significant decrease of the performance of these electrodes. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Performance analysis of a SOFC under direct internal reforming conditions

    Energy Technology Data Exchange (ETDEWEB)

    Janardhanan, Vinod M.; Deutschmann, Olaf [Institute for Chemical Technology and Polymer Chemistry, Engesserstr 20, D-76131 Karlsruhe, University of Karlsruhe (Germany); Heuveline, Vincent [Institute for Applied and Numerical Mathematics, Kaiserstr. 12, D-76128 Karlsruhe (Germany)

    2007-10-11

    This paper presents the performance analysis of a planar solid-oxide fuel cell (SOFC) under direct internal reforming conditions. A detailed solid-oxide fuel cell model is used to study the influences of various operating parameters on cell performance. Significant differences in efficiency and power density are observed for isothermal and adiabatic operational regimes. The influence of air number, specific catalyst area, anode thickness, steam to carbon (s/c) ratio of the inlet fuel, and extend of pre-reforming on cell performance is analyzed. In all cases except for the case of pre-reformed fuel, adiabatic operation results in lower performance compared to isothermal operation. It is further discussed that, though direct internal reforming may lead to cost reduction and increased efficiency by effective utilization of waste heat, the efficiency of the fuel cell itself is higher for pre-reformed fuel compared to non-reformed fuel. Furthermore, criteria for the choice of optimal operating conditions for cell stacks operating under direct internal reforming conditions are discussed. (author)

  13. Performance analysis of a SOFC under direct internal reforming conditions

    Science.gov (United States)

    Janardhanan, Vinod M.; Heuveline, Vincent; Deutschmann, Olaf

    This paper presents the performance analysis of a planar solid-oxide fuel cell (SOFC) under direct internal reforming conditions. A detailed solid-oxide fuel cell model is used to study the influences of various operating parameters on cell performance. Significant differences in efficiency and power density are observed for isothermal and adiabatic operational regimes. The influence of air number, specific catalyst area, anode thickness, steam to carbon (s/c) ratio of the inlet fuel, and extend of pre-reforming on cell performance is analyzed. In all cases except for the case of pre-reformed fuel, adiabatic operation results in lower performance compared to isothermal operation. It is further discussed that, though direct internal reforming may lead to cost reduction and increased efficiency by effective utilization of waste heat, the efficiency of the fuel cell itself is higher for pre-reformed fuel compared to non-reformed fuel. Furthermore, criteria for the choice of optimal operating conditions for cell stacks operating under direct internal reforming conditions are discussed.

  14. Reversible solid oxide fuel cells (R-SOFCs) with chemically stable proton-conducting oxides

    KAUST Repository

    Bi, Lei

    2015-07-01

    Proton-conducting oxides offer a promising way of lowering the working temperature of solid oxide cells to the intermediate temperate range (500 to 700. °C) due to their better ionic conductivity. In addition, the application of proton-conducting oxides in both solid oxide fuel cells (SOFCs) and sold oxide electrolysis cells (SOECs) provides unique advantages compared with the use of conventional oxygen-ion conducting conductors, including the formation of water at the air electrode site. Since the discovery of proton conduction in some oxides about 30. years ago, the development of proton-conducting oxides in SOFCs and SOECs (the reverse mode of SOFCs) has gained increased attention. This paper briefly summarizes the development in the recent years of R-SOFCs with proton-conducting electrolytes, focusing on discussing the importance of adopting chemically stable materials in both fuel cell and electrolysis modes. The development of electrode materials for proton-conducting R-SOFCs is also discussed. © 2015 Elsevier B.V.

  15. Modeling and Analysis of Transport Processes and Efficiency of Combined SOFC and PEMFC Systems

    Directory of Open Access Journals (Sweden)

    Abid Rabbani

    2014-08-01

    Full Text Available A hybrid fuel cell system (~10 kWe for an average family house including heating is proposed. The investigated system comprises a Solid Oxide Fuel Cell (SOFC on top of a Polymer Electrolyte Fuel Cell (PEFC. Hydrogen produced from the off-gases of the SOFC can be fed directly to the PEFC. Simulations for the proposed system were conducted using different fuels. Here, results for natural gas (NG, dimethyl ether (DME and ethanol as a fuel are presented and analysed. Behaviour of the proposed system is further investigated by comparing the effects of key factors such as utilisation factor, operating conditions, oxygen-to-carbon (O/C ratios and fuel preheating effects on these fuels. The combined system improves the overall electrical conversion efficiency compared with standalone PEFC or SOFC systems. For the combined SOFC and PEFC system, the overall power production was increased by 8%–16% and the system efficiency with one of the fuels is found to be 12% higher than that of the standalone SOFC system.

  16. Electro-catalysts for hydrogen production from ethanol for use in SOFC anodes

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marcos Aurelio da; Paz Fiuza, Raigenis da; Guedes, Bruna C.; Pontes, Luiz A.; Boaventura, Jaime Soares [UFBA, Salvador, Bahia (Brazil). Energy and Materials Science Group

    2010-07-01

    Nickel and cobalt catalysts, supported on YSZ, were prepared by wet impregnation, with and without citric acid; the metal load was 10 and 35% by weight. The catalyst composition was studied by XRF, XPS and SEM-EDS. At low metal concentration, the results of these techniques presented comparables figures; at high concentration, SEM-EDS suggested a non-uniform distribution. The analysis showed that the solids were mixed oxides and formed an alloy after reduction. The surface passivation was possible under controlled conditions. The catalytic test with the steam reforming of ethanol indicated that the metal load had almost no effect on the catalytic activity, but decreased its selectivity. Afterwards, a unitary SOFC was prepared with deposition of the cathode layer. AFM and EIS were used for the characterization of SOFC components. They showed that the electro-catalyst surface was almost all covered with the metal phase, including the large pore walls of the anode. The YSZ phase dominates the material conductance of the complete SOFC assembly (anode/electrolyte/cathode). The unitary SOFC was tested with hydrogen, gaseous ethanol or natural gas; the SOFC operating with ethanol and hydrogen fuel presented virtually no over-potential. (orig.)

  17. Development of solid oxide fuel cells; Desenvolvimento de celulas a combustivel do tipo oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Boaventura, Jaime S.; Alencar, Marcelo Goncalves F. de; Amaral, Alexandre Alves do; Benedicto, Joao Paulo Santos; Silva, Marcos A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica. Dept. de Fisico-Quimica

    2006-07-01

    Fuel cells allow the energy production without the thermodynamic restriction of the conversion of heat into work. Among their various types, the solid oxide fuel cells (SOFC), operating at high temperatures, allow the methane conversion into electricity directly on the anode. The main element of the SOFC is the structure A/E/C: anode/electrolyte/cathode, all sintered at high temperature as resistant ceramic materials. Dense electrolyte (YSZ: zirconia stabilized for Yttria) separates the anode (Ni+Co/YSZ: cobalt promoted nickel, supported on YSZ) and cathode (LSM: strontium-doped lanthanum manganite), both with porosity obtained by graphite addition. To obtain suitable A/E/C pellets, the layer sintering with appropriate mechanical and textural characteristics is essential, requiring excellent electric junctions between them. The cell performance has been evaluated between 850 and 950 degree C, using hydrogen or methane fuel; the tension and current for different resistance values in the electrical circuit have been measured. The cobalt addition to the cell anode significantly increased its activity for the reform reaction. The beneficial effect was probably due to the easier nickel reduction in cobalt presence. This work had the objectives of developing and evaluating electro-catalysts, as well as the solid oxide fuel cells using these catalysts as anode. Five SOFC models (SOFC 1 to SOFC 5) are described; all of them were developed aiming at improving the preparation of the anode/electrolyte/cathode structure (A/E/C). (author)

  18. Infiltration of SOFC Stacks: Evaluation of the Electrochemical Performance Enhancement and the Underlying Changes in the Microstructure

    DEFF Research Database (Denmark)

    Kiebach, Wolff-Ragnar; Zielke, Philipp; Høgh, Jens Valdemar Thorvald

    2016-01-01

    Experimental SOFC stacks with 10 SOFCs (LSM-YSZ/YSZ/Ni-YSZ) were infiltrated with CGO and Ni-CGO on the air and fuel side, respectively in an attempt to counter degradation and improve the output. The electrochemical performance of each cell was characterized (i) before infiltration, (ii) after i...

  19. SOFC LSM:YSZ cathode degradation induced by moisture: An impedance spectroscopy study

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Mogensen, Mogens Bjerg

    2011-01-01

    The cause of the degradation effect of moisture during operation of LSM cathode based SOFCs has been investigated by means of a detailed impedance characterization on LSM:YSZ composite cathode based SOFCs. Further the role of YSZ as cathode composite material was studied by measurements on SOFCs...... with a LSM:CGO composite cathode on a CGO interdiffusion barrier layer. It was found that both types of cathodes showed similar electrochemical characteristics towards the presence of moisture during operation. Upon addition and removal of moisture in the fed air the impedance study showed a change...... in the high frequency cathode arc, which is associated with the charge transport/transfer at the LSM/YSZ interface. On prolonged operation with the presence of moisture an ongoing increase in the high frequency cathode arc resulted in a permanent loss of cathode/electrolyte contact and thus increase...

  20. Robust automatic high resolution segmentation of SOFC anode porosity in 3D

    DEFF Research Database (Denmark)

    Jørgensen, Peter Stanley; Bowen, Jacob R.

    2008-01-01

    Routine use of 3D characterization of SOFCs by focused ion beam (FIB) serial sectioning is generally restricted by the time consuming task of manually delineating structures within each image slice. We apply advanced image analysis algorithms to automatically segment the porosity phase of an SOFC...... anode in 3D. The technique is based on numerical approximations to partial differential equations to evolve a 3D surface to the desired phase boundary. Vector fields derived from the experimentally acquired data are used as the driving force. The automatic segmentation compared to manual delineation...... reveals and good correspondence and the two approaches are quantitatively compared. It is concluded that the. automatic approach is more robust, more reproduceable and orders of magnitude quicker than manual segmentation of SOFC anode porosity for subsequent quantitative 3D analysis. Lastly...

  1. Oxygen reduction kinetics on mixed conducting SOFC model cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, F.S.

    2006-07-01

    The kinetics of the oxygen reduction reaction at the surface of mixed conducting solid oxide fuel cell (SOFC) cathodes is one of the main limiting factors to the performance of these promising systems. For ''realistic'' porous electrodes, however, it is usually very difficult to separate the influence of different resistive processes. Therefore, a suitable, geometrically well-defined model system was used in this work to enable an unambiguous distinction of individual electrochemical processes by means of impedance spectroscopy. The electrochemical measurements were performed on dense thin film microelectrodes, prepared by PLD and photolithography, of mixed conducting perovskite-type materials. The first part of the thesis consists of an extensive impedance spectroscopic investigation of La0.6Sr0.4Co0.8Fe0.2O3 (LSCF) microelectrodes. An equivalent circuit was identified that describes the electrochemical properties of the model electrodes appropriately and enables an unambiguous interpretation of the measured impedance spectra. Hence, the dependencies of individual electrochemical processes such as the surface exchange reaction on a wide range of experimental parameters including temperature, dc bias and oxygen partial pressure could be studied. As a result, a comprehensive set of experimental data has been obtained, which was previously not available for a mixed conducting model system. In the course of the experiments on the dc bias dependence of the electrochemical processes a new and surprising effect was discovered: It could be shown that a short but strong dc polarisation of a LSCF microelectrode at high temperature improves its electrochemical performance with respect to the oxygen reduction reaction drastically. The electrochemical resistance associated with the oxygen surface exchange reaction, initially the dominant contribution to the total electrode resistance, can be reduced by two orders of magnitude. This &apos

  2. Thermodynamic Model of a Very High Efficiency Power Plant based on a Biomass Gasifier, SOFCs, and a Gas Turbine

    Directory of Open Access Journals (Sweden)

    P V Aravind

    2012-07-01

    Full Text Available Thermodynamic calculations with a power plant based on a biomass gasifier, SOFCs and a gas turbine are presented. The SOFC anode off-gas which mainly consists of steam and carbon dioxides used as a gasifying agent leading to an allothermal gasification process for which heat is required. Implementation of heat pipes between the SOFC and the gasifier using two SOFC stacks and intercooling the fuel and the cathode streams in between them has shown to be a solution on one hand to drive the allothermal gasification process and on the other hand to cool down the SOFC. It is seen that this helps to reduce the exergy losses in the system significantly. With such a system, electrical efficiency around 73% is shown as achievable.

  3. Advanced Measurement and Modeling Techniques for Improved SOFC Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Adler; L. Dunyushkina; S. Huff; Y. Lu; J. Wilson

    2006-12-31

    The goal of this project was to develop an improved understanding of factors governing performance and degradation of mixed-conducting SOFC cathodes. Two new diagnostic tools were developed to help achieve this goal: (1) microelectrode half-cells for improved isolation of cathode impedance on thin electrolytes, and (2) nonlinear electrochemical impedance spectroscopy (NLEIS), a variant of traditional impedance that allows workers to probe nonlinear rates as a function of frequency. After reporting on the development and efficacy of these tools, this document reports on the use of these and other tools to better understand performance and degradation of cathodes based on the mixed conductor La{sub 1-x}Sr{sub x}CoO{sub 3-{delta}} (LSC) on gadolinia or samaria-doped ceria (GDC or SDC). We describe the use of NLEIS to measure O{sub 2} exchange on thin-film LSC electrodes, and show that O{sub 2} exchange is most likely governed by dissociative adsorption. We also describe parametric studies of porous LSC electrodes using impedance and NLEIS. Our results suggest that O{sub 2} exchange and ion transport co-limit performance under most relevant conditions, but it is O{sub 2} exchange that is most sensitive to processing, and subject to the greatest degradation and sample-to-sample variation. We recommend further work that focuses on electrodes of well-defined or characterized geometry, and probes the details of surface structure, composition, and impurities. Parallel work on primarily electronic conductors (LSM) would also be of benefit to developers, and to improved understanding of surface vs. bulk diffusion.

  4. Thermodynamic and Thermoeconomic investigation of an Integrated Gasification SOFC and Stirling Engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2013-01-01

    Thermodynamic and thermoeconomic investigation of a small scale Integrated Gasification Solid Oxide Fuel Cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120kW have been performed. Woodchips are used as gasification feedstock to produce syngas which......-product and the cost of hot water was found to be 0.0214$/kWh. When compared to other renewable systems at similar scale, it shows that if both SOFC and Stirling engine technology emerges enter commercialization phase, then they can deliver electricity at a cost rate which is competitive with corresponding renewable...

  5. Quality Assurance of Solid Oxide Fuel Cell (SOFC) and Electrolyser (SOEC) Stacks

    DEFF Research Database (Denmark)

    Lang, Michael; Auer, Corinna; Couturier, Karine

    2017-01-01

    In the EU-funded project “Solid oxide cell and stack testing and quality assurance” (SOCTESQA) standardized and industry wide test modules and programs for high temperature solid oxide cells and stacks are being developed. These test procedures can be applied for the fuel cell (SOFC......), the electrolysis (SOEC) and in the combined SOFC/SOEC mode. In order to optimize the test modules the project partners have tested identical SOC stacks with the same test programs in several testing campaigns. Altogether 10 pre-normative test modules were developed: Start-up, current-voltage characteristics...

  6. Binary co-generative plants with height temperature SOFC fuel cells

    International Nuclear Information System (INIS)

    Tashevski, D; Dimitrov, K.; Armenski, S.

    2005-01-01

    In this paper, a field of binary co-generative plants with height temperature SOFC fuel cells is presented. Special attention of application of height temperature SOFC fuel cells and binary co-generative units has been given. These units made triple electricity and heat. Principle of combination of fuel cells with binary cycles has been presented. A model and computer programme for calculation of BKPFC, has been created. By using the program, all the important characteristic-results are calculated: power, efficiency, emission, dimension and economic analysis. On base of results, conclusions and recommendations has been given. (Author)

  7. Binary co-generative plants with height temperature SOFC fuel cells

    International Nuclear Information System (INIS)

    Tashevski, D; Dimitrov, K.; Armenski, S.

    2006-01-01

    In this paper, a field of binary co-generative plants with height temperature SOFC fuel cells is presented. Special attention of application of height temperature SOFC fuel cells and binary co-generative units has been given. These units made triple electricity and heat. Principle of combination of fuel cells with binary cycles has been presented. A model and computer programme for calculation of BKPFC, has been created. By using the program, all the important characteristic-results are calculated: power, efficiency, emission, dimension and economic analysis. On base of results, conclusions and recommendations has been given. (Author)

  8. Vaporization of materials in the operation of high temperature fuel cells (SOFCs); Verdampfung von Werkstoffen beim Betrieb von Hochtemperaturbrennstoffzellen (SOFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Stanislowski, M.

    2006-07-01

    One of the main problems concerning the development of state of the art planar SOFCs are the occurrence of ageing effects in long term application. To a great deal these effects are caused by the release of volatile Cr-species from metallic interconnects which leads to an inhibition of the electrochemical processes at the cathode resulting in a rapid degradation of the cell performance. A goal in further development of SOFC-systems is the reduction of the operation temperature of the cell from currently 800 C to 700 C and below. For this purpose alternative electrolyte materials with higher oxygen ion conductivities have to be developed. Doped lanthanum gallates have been identified as promising materials. However for these materials a depletion of Ga by vaporization has been observed under anodic conditions which may lead to a destruction of their electrolyte properties. The aim of this work is the study of the vaporization processes leading to the mentioned degradation effects. For this purpose an experimental setup according to the transpiration method has been developed. Concerning the vaporization of chromium the Cr release rates of the main ferritic interconnect alloys, namely Crofer 22 APU, ZMG 232, E-Brite, IT-10, IT-11, IT-14 and Ducrolloy as well as a variety of Ni- and Co-base superalloys and stainless steels with different contents of Al, Si, Ti, Mn, W, Ni and Co were measured at 800 C in air and compared to each other. The alloys that form an upper layer of Cr-Mn-spinel on top of the grown chromia scale showed a reduction of the Cr release by 61-75 % compared to pure chromia scales whereas alloys with an outer Co3O4(s) scale had a by more than 90 % reduced Cr release. For the former alloys a significant vaporization of Mn under anodic conditions could be detected. Concerning the vaporization of doped lanthanum gallates the vaporization rates of the elements Ga, Mg, Sr and La were measured as function time, temperature, gas flow rate and stoichiometry

  9. Hydrogen Fueled Hybrid Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) System for Long-Haul Rail Application

    Science.gov (United States)

    Chow, Justin Jeff

    Freight movement of goods is the artery for America's economic health. Long-haul rail is the premier mode of transport on a ton-mile basis. Concerns regarding greenhouse gas and criteria pollutant emissions, however, have motivated the creation of annually increasing locomotive emissions standards. Health issues from diesel particulate matter, especially near rail yards, have also been on the rise. These factors and the potential to raise conventional diesel-electric locomotive performance warrants the investigation of using future fuels in a more efficient system for locomotive application. This research evaluates the dynamic performance of a Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) Hybrid system operating on hydrogen fuel to power a locomotive over a rail path starting from the Port of Los Angeles and ending in the City of Barstow. Physical constraints, representative locomotive operation logic, and basic design are used from a previous feasibility study and simulations are performed in the MATLAB Simulink environment. In-house controls are adapted to and expanded upon. Results indicate high fuel-to-electricity efficiencies of at least 54% compared to a conventional diesel-electric locomotive efficiency of 35%. Incorporation of properly calibrated feedback and feed-forward controls enables substantial load following of difficult transients that result from train kinematics while maintaining turbomachinery operating requirements and suppressing thermal stresses in the fuel cell stack. The power split between the SOFC and gas turbine is deduced to be a deterministic factor in the balance between capital and operational costs. Using hydrogen results in no emissions if renewable and offers a potential of 24.2% fuel energy savings for the rail industry.

  10. Feasibility study for SOFC-GT hybrid locomotive power: Part I. Development of a dynamic 3.5 MW SOFC-GT FORTRAN model

    Science.gov (United States)

    Martinez, Andrew S.; Brouwer, Jacob; Samuelsen, G. Scott

    2012-09-01

    This work presents the development of a dynamic SOFC-GT hybrid system model applied to a long-haul freight locomotive in operation. Given the expectations of the rail industry, the model is used to develop a preliminary analysis of the proposed system's operational capability on conventional diesel fuel as well as natural gas and hydrogen as potential fuels in the future. It is found that operation of the system on all three of these fuels is feasible with favorable efficiencies and reasonable dynamic response. The use of diesel fuel reformate in the SOFC presents a challenge to the electrochemistry, especially as it relates to control and optimization of the fuel utilization in the anode compartment. This is found to arise from the large amount of carbon monoxide in diesel reformate that is fed to the fuel cell, limiting the maximum fuel utilization possible. This presents an opportunity for further investigations into carbon monoxide electrochemical oxidation and/or system integration studies where the efficiency of the fuel reformer can be balanced against the needs of the SOFC.

  11. Combining science and practice in the Danish DK-SOFC program

    DEFF Research Database (Denmark)

    Knudsen, P.; Bagger, C.; Mogensen, Mogens Bjerg

    1994-01-01

    A three-year solid oxide fuel cells (SOFC) development program completed in 1992 has produced 10 cm2 cells with area-specific resistances in the range 0.25 to 0.40 OMEGA cm2 at 1000-degrees-C. Cathode and interconnect materials were produced in the program. Sintering of electrodes, electrolyte...

  12. Progress of SOFC/SOEC Development at DTU Energy: From Materials to Systems

    DEFF Research Database (Denmark)

    Hagen, Anke; Hendriksen, Peter Vang

    2017-01-01

    DTU Energy has over the past 20 years had a very substantial effort on SOFC/SOEC development. The current project volume corresponds to ~40 man years per year. Activities span over a broad range in the value chain, from materials to cells, stacks and analyses at energy system level. In addition...

  13. SOFC anode. Hydrogen oxidation at porous nickel and nickel/zirconia electrodes

    NARCIS (Netherlands)

    de Boer, B.

    1998-01-01

    In the ongoing search for alternative and environmental friendly power generation facilities, the fuel cell is a good candidate. There are several types of fuel cells with large differences in application, size, cost and operating range. The Solid Oxide Fuel Cell (SOFC) is a high temperature fuel

  14. Operation of real landfill gas fueled solid oxide fuel cell (SOFC) using internal dry reforming

    DEFF Research Database (Denmark)

    Langnickel, Hendrik; Hagen, Anke

    2017-01-01

    Biomass is one renewable energy source, which is independent from solar radiation and wind effect. Solid oxide fuel cells (SOFC’s) are able to convert landfill gas derived from landfill directly into electricity and heat with a high efficiency. In the present work a planar 16cm2 SOFC cell...... was necessary to prevent poisoning and thereby to decrease the degradation rate....

  15. The Effect of H2S on the Performance of SOFCs using Methane Containing Fuel

    DEFF Research Database (Denmark)

    Rasmussen, Jens Foldager Bregnballe; Hagen, Anke

    2010-01-01

    In recent years, the interest for using biogas derived from biomass as fuel in solid oxide fuel cells (SOFCs) has increased. To maximise the biogas to electrical energy output, it is important to study the effects of the main biogas components (CH4 and CO2), minor ones and traces (e.g. H2S...

  16. Thermodynamic analysis and optimization of IT-SOFC-based integrated coal gasification fuel cell power plants

    NARCIS (Netherlands)

    Romano, M.C.; Campanari, S.; Spallina, V.; Lozza, G.

    2011-01-01

    This work discusses the thermodynamic analysis of integrated gasification fuel cell plants, where a simple cycle gas turbine works in a hybrid cycle with a pressurized intermediate temperature–solid oxide fuel cell (SOFC), integrated with a coal gasification and syngas cleanup island and a bottoming

  17. The financial viability of an SOFC cogeneration system in single-family dwellings

    Science.gov (United States)

    Alanne, Kari; Saari, Arto; Ugursal, V. Ismet; Good, Joel

    In the near future, fuel cell-based residential micro-CHP systems will compete with traditional methods of energy supply. A micro-CHP system may be considered viable if its incremental capital cost compared to its competitors equals to cumulated savings during a given period of time. A simplified model is developed in this study to estimate the operation of a residential solid oxide fuel cell (SOFC) system. A comparative assessment of the SOFC system vis-à-vis heating systems based on gas, oil and electricity is conducted using the simplified model for a single-family house located in Ottawa and Vancouver. The energy consumption of the house is estimated using the HOT2000 building simulation program. A financial analysis is carried out to evaluate the sensitivity of the maximum allowable capital cost with respect to system sizing, acceptable payback period, energy price and the electricity buyback strategy of an energy utility. Based on the financial analysis, small (1-2 kW e) SOFC systems seem to be feasible in the considered case. The present study shows also that an SOFC system is especially an alternative to heating systems based on oil and electrical furnaces.

  18. Study of Internal and External Leaks in Tests of Anode-Supported SOFCs

    DEFF Research Database (Denmark)

    Rasmussen, Jens Foldager Bregnballe; Hendriksen, Peter Vang; Hagen, Anke

    2008-01-01

    A planar anode-supported solid oxide fuel cell (SOFC) has been tested to investigate gas tightness of the electrolyte and the applied seals. Gas leaks reduce the efficiency of the SOFC and it is thus important to determine and minimise them. Probe gases (He and Ar) and a Quadrupole Mass Spectrome......A planar anode-supported solid oxide fuel cell (SOFC) has been tested to investigate gas tightness of the electrolyte and the applied seals. Gas leaks reduce the efficiency of the SOFC and it is thus important to determine and minimise them. Probe gases (He and Ar) and a Quadrupole Mass...... Spectrometer were used to detect both internal (through electrolyte) and external (through seals) gas leaks. The internal gas leak through the electrolyte was quantified under different conditions, as was the external leak from the surroundings to the anode. The internal gas leak did not depend on the pressure...... difference between the anode and the cathode gas compartment, and can thus be described as diffusion driven. External leaks between the surroundings and the anode, but not the cathode gas compartment was observed. They were influenced by the pressure difference and are thus driven by both concentration...

  19. Control-relevant modeling and simulation of a SOFC-GT hybrid system

    Directory of Open Access Journals (Sweden)

    Rambabu Kandepu

    2006-07-01

    Full Text Available In this paper, control-relevant models of the most important components in a SOFC-GT hybrid system are described. Dynamic simulations are performed on the overall hybrid system. The model is used to develop a simple control structure, but the simulations show that more elaborate control is needed.

  20. Control-relevant modeling and simulation of a SOFC-GT hybrid system

    OpenAIRE

    Rambabu Kandepu; Lars Imsland; Christoph Stiller; Bjarne A. Foss; Vinay Kariwala

    2006-01-01

    In this paper, control-relevant models of the most important components in a SOFC-GT hybrid system are described. Dynamic simulations are performed on the overall hybrid system. The model is used to develop a simple control structure, but the simulations show that more elaborate control is needed.

  1. SOFC regulation at constant temperature: Experimental test and data regression study

    International Nuclear Information System (INIS)

    Barelli, L.; Bidini, G.; Cinti, G.; Ottaviano, A.

    2016-01-01

    Highlights: • SOFC operating temperature impacts strongly on its performance and lifetime. • Experimental tests were carried out varying electric load and feeding mixture gas. • Three different anodic inlet gases were tested maintaining constant temperature. • Cathodic air flow rate was used to maintain constant its operating temperature. • Regression law was defined from experimental data to regulate the air flow rate. - Abstract: The operating temperature of solid oxide fuel cell stack (SOFC) is an important parameter to be controlled, which impacts the SOFC performance and its lifetime. Rapid temperature change implies a significant temperature differences between the surface and the mean body leading to a state of thermal shock. Thermal shock and thermal cycling introduce stress in a material due to temperature differences between the surface and the interior, or between different regions of the cell. In this context, in order to determine a control law that permit to maintain constant the fuel cell temperature varying the electrical load and the infeed fuel mixture, an experimental activity were carried out on a planar SOFC short stack to analyse stack temperature. Specifically, three different anodic inlet gas compositions were tested: pure hydrogen, reformed natural gas with steam to carbon ratio equal to 2 and 2.5. By processing the obtained results, a regression law was defined to regulate the air flow rate to be provided to the fuel cell to maintain constant its operating temperature varying its operating conditions.

  2. Thermo-mechanical properties of SOFC components investigated by a combined method

    DEFF Research Database (Denmark)

    Teocoli, Francesca; Esposito, Vincenzo; Ramousse, Severine

    , and differential thermo-mechanical behavior at each layer. The combination of such factors can have a critical effect on the final shape and microstructure, and on the mechanical integrity. Thermo-mechanical properties and sintering mechanisms of important SOFC materials (CGO, YSZ, ScYSZ) were systematically...

  3. Cr-tolerance of the IT-SOFC La(Ni,Fe)O3 material

    NARCIS (Netherlands)

    Stodolny, M.K.

    2012-01-01

    This thesis deals with a study on the Cr-tolerance of the LaNi0.6Fe0.4O3 (LNF) material. LNF is being considered for use as a current collecting layer, an interconnect protective coating and/or an electrochemically active solid oxide fuel cell (SOFC) cathode layer in an intermediate temperature

  4. A SOFC-based integrated gasification fuel cell cycle with CO2 capture

    NARCIS (Netherlands)

    Spallina, V.; Romano, M.C.; Campanari, S.; Lozza, G.

    2011-01-01

    The application of solid oxide fuel cells (SOFC) in gasification-based power plants would represent a turning point in the power generation sector, allowing to considerably increase the electric efficiency of coal-fired power stations. Pollutant emissions would also be significantly reduced in

  5. Effect of Samarium Oxide on the Electrical Conductivity of Plasma-Sprayed SOFC Anodes

    Science.gov (United States)

    Panahi, S. N.; Samadi, H.; Nemati, A.

    2016-10-01

    Solid oxide fuel cells (SOFCs) are rapidly becoming recognized as a new alternative to traditional energy conversion systems because of their high energy efficiency. From an ecological perspective, this environmentally friendly technology, which produces clean energy, is likely to be implemented more frequently in the future. However, the current SOFC technology still cannot meet the demands of commercial applications due to temperature constraints and high cost. To develop a marketable SOFC, suppliers have tended to reduce the operating temperatures by a few hundred degrees. The overall trend for SOFC materials is to reduce their service temperature of electrolyte. Meanwhile, it is important that the other components perform at the same temperature. Currently, the anodes of SOFCs are being studied in depth. Research has indicated that anodes based on a perovskite structure are a more promising candidate in SOFCs than the traditional system because they possess more favorable electrical properties. Among the perovskite-type oxides, SrTiO3 is one of the most promising compositions, with studies demonstrating that SrTiO3 exhibits particularly favorable electrical properties in contrast with other perovskite-type oxides. The main purpose of this article is to describe our study of the effect of rare-earth dopants with a perovskite structure on the electrical behavior of anodes in SOFCs. Sm2O3-doped SrTiO3 synthesized by a solid-state reaction was coated on substrate by atmospheric plasma spray. To compare the effect of the dopant on the electrical conductivity of strontium titanate, different concentrations of Sm2O3 were used. The samples were then investigated by x-ray diffraction, four-point probe at various temperatures (to determine the electrical conductivity), and a scanning electron microscope. The study showed that at room temperature, nondoped samples have a higher electrical resistance than doped samples. As the temperature was increased, the electrical

  6. Performance analysis of a co-generation system using solar energy and SOFC technology

    International Nuclear Information System (INIS)

    Akikur, R.K.; Saidur, R.; Ping, H.W.; Ullah, K.R.

    2014-01-01

    Highlights: • A new concept of a cogeneration system is proposed and investigated. • The system comprises solar collector, PV, SOFC and heat exchanger. • 83.6% Power and heat generation efficiency has been found at fuel cell mode. • 85.1% Efficiency of SOSE has been found at H2 production mode. • The heat to power ratio of SOFC mode has been found about 0.917. - Abstract: Due to the increasing future energy demands and global warming, the renewable alternative energy sources and the efficient power systems have been getting importance over the last few decades. Among the renewable energy technologies, the solar energy coupling with fuel cell technology will be the promising possibilities for the future green energy solutions. Fuel cell cogeneration is an auspicious technology that can potentially reduce the energy consumption and environmental impact associated with serving building electrical and thermal demands. In this study, performance assessment of a co-generation system is presented to deliver electrical and thermal energy using the solar energy and the reversible solid oxide fuel cell. A mathematical model of the co-generation system is developed. To illustrate the performance, the system is considered in three operation modes: a solar-solid oxide fuel cell (SOFC) mode, which is low solar radiation time when the solar photovoltaic (PV) and SOFC are used for electric and heat load supply; a solar-solid oxide steam electrolyzer (SOSE) mode, which is high solar radiation time when PV is used for power supply to the electrical load and to the steam electrolyzer to generate hydrogen (H 2 ); and a SOFC mode, which is the power and heat generation mode of reversible SOFC using the storage H 2 at night time. Also the effects of solar radiation on the system performances and the effects of temperature on RSOFC are analyzed. In this study, 100 kW electric loads are considered and analyzed for the power and heat generation in those three modes to evaluate

  7. Use of wastewater treatment plant biogas for the operation of Solid Oxide Fuel Cells (SOFCs).

    Science.gov (United States)

    Lackey, Jillian; Champagne, Pascale; Peppley, Brant

    2017-12-01

    Solid Oxide Fuel Cells (SOFCs) perform well on light hydrocarbon fuels, and the use of biogas derived from the anaerobic digestion (AD) of municipal wastewater sludges could provide an opportunity for the CH 4 produced to be used as a renewable fuel. Greenhouse gas (GHG), NO x , SO x , and hydrocarbon pollutant emissions would also be reduced. In this study, SOFCs were operated on AD derived biogas. Initially, different H 2 dilutions were tested (N 2 , Ar, CO 2 ) to examine the performance of tubular SOFCs. With inert gases as diluents, a decrease in cell performance was observed, however, the use of CO 2 led to a higher decrease in performance as it promoted the reverse water-gas shift (WGS) reaction, reducing the H 2 partial pressure in the gas mixture. A model was developed to predict system efficiency and GHG emissions. A higher electrical system efficiency was noted for a steam:carbon ratio of 2 compared to 1 due to the increased H 2 partial pressure in the reformate resulting from higher H 2 O concentration. Reductions in GHG emissions were estimated at 2400 tonnes CO 2 , 60 kg CH 4 and 18 kg N 2 O. SOFCs were also tested using a simulated biogas reformate mixture (66.7% H 2 , 16.1% CO, 16.5% CO 2 , 0.7% N 2 , humidified to 2.3 or 20 mol% H 2 O). Higher humidification yielded better performance as the WGS reaction produced more H 2 with additional H 2 O. It was concluded that AD-derived biogas, when cleaned to remove H 2 S, Si compounds, halides and other contaminants, could be reformed to provide a clean, renewable fuel for SOFCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Chemistry of SOFC Cathode Surfaces: Fundamental Investigation and Tailoring of Electronic Behavior

    Energy Technology Data Exchange (ETDEWEB)

    Yildiz, Bilge; Heski, Clemens

    2013-08-31

    1) Electron tunneling characteristics on La0.7Sr0.3MnO3 (LSM) thin-film surfaces were studied up to 580oC in 10-3mbar oxygen pressure, using scanning tunneling microscopy/ spectroscopy (STM/STS). A threshold-like drop in the tunneling current was observed at positive bias in STS, which is interpreted as a unique indicator for the activation polarization in cation oxygen bonding on LSM cathodes. Sr-enrichment was found on the surface at high temperature using Auger electron spectroscopy, and was accompanied by a decrease in tunneling conductance in STS. This suggests that Sr-terminated surfaces are less active for electron transfer in oxygen reduction compared to Mn-terminated surfaces on LSM. 2) Effects of strain on the surface cation chemistry and the electronic structure are important to understand and control for attaining fast oxygen reduction kinetics on transition metal oxides. Here, we demonstrate and mechanistically interpret the strain coupling to Sr segregation, oxygen vacancy formation, and electronic structure on the surface of La0.7Sr0.3MnO3 (LSM) thin films as a model system. Our experimental results from x-ray photoelectron spectroscopy and scanning tunneling spectroscopy are discussed in light of our first principles-based calculations. A stronger Sr enrichment tendency and a more facile oxygen vacancy formation prevail for the tensile strained LSM surface. The electronic structure of the tensile strained LSM surface exhibits a larger band gap at room temperature, however, a higher tunneling conductance near the Fermi level than the compressively strained LSM at elevated temperatures in oxygen. Our findings suggest lattice strain as a key parameter to tune the reactivity of perovskite transition metal oxides with oxygen in solid oxide fuel cell cathodes. 3) Cation segregation on perovskite oxide surfaces affects vastly the oxygen reduction activity and stability of solid oxide fuel cell (SOFC) cathodes. A unified theory that explains the physical

  9. Singler-chamber SOFCs based on gadolinia doped ceria operated on methane and propane; Pilas de combustible de una sola camara, basadas en electrolitos de ceria dopada con gadolinia y operadas con metano y propano

    Energy Technology Data Exchange (ETDEWEB)

    Morales, M.; Roa, J. J.; Capdevila, X. G.; Segarra, M.; Pinol, S.

    2010-07-01

    The main advantages of single-chamber solid oxide fuel cells (SOFCs) respect to dual-chamber SOFCs, are to simplify the device design and to operate in mixtures of hydrocarbon (methane, propane...) and air, with no separation between fuel and oxidant. However, this design requires the use of selective electrodes for the fuel oxidation and the oxidant reduction. In this work, electrolyte-supported SOFCs were fabricated using gadolinia doped ceria (GDC) as the electrolyte, Ni + GDC as the anode and LSC(La{sub 0}.5Sr{sub 0}.5CoO{sub 3}-{delta})-GDC-Ag{sub 2}O as the cathode. The electrical properties of the cell were determined in mixtures of methane + air and propane + air. The influence of temperature, gas composition and total flow rate on the fuel cell performance was investigated. As a result, the power density was strongly increased with increasing temperature, total flow rate and hydrocarbon composition. Under optimized gas compositions and total flow conditions, power densities of 70 and 320 mW/cm{sup 2} operating on propane at a temperature of 600 degree centigrade and methane (795 degree centigrade) were obtained, respectively. (Author)

  10. Reversibility of the SOFC for the hydrogen production by high temperature electrolysis; Reversibilite des SOFC pour la production d'hydrogene par electrolyse haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Brisse, A.; Marrony, M.; Perednis, D.; Schefold, J.; Jose-Garcia, M.; Zahid, M. [Institut Europeen de Recherche sur l' Energie (EIFER), Karlsruhe (Germany)

    2007-07-01

    The behaviour of two SOFC cells in electrolysis mode is studied. The performances of these solid oxide cells, reversible at 800 C and for current densities between 0 and -0.42 A/cm{sup 2}, are presented. A weaker polarisation resistance has been measured for the cell containing a mixed conductor as oxygen electrode. For each cell, a limitation by gaseous diffusion has been observed under current. This phenomenon appears for current densities which are higher for the mixed conductor cell as oxygen electrode. (O.M.)

  11. Feasibility study for SOFC-GT hybrid locomotive power: Part I. Development of a dynamic 3.5 MW SOFC-GT FORTRAN model

    OpenAIRE

    Martinez, AS; Brouwer, J; Samuelsen, GS

    2012-01-01

    This work presents the development of a dynamic SOFC-GT hybrid system model applied to a long-haul freight locomotive in operation. Given the expectations of the rail industry, the model is used to develop a preliminary analysis of the proposed system's operational capability on conventional diesel fuel as well as natural gas and hydrogen as potential fuels in the future. It is found that operation of the system on all three of these fuels is feasible with favorable efficiencies and reasonabl...

  12. Preparation of cathode materials for solid oxide solid fuel (SOFC) using gelatin

    International Nuclear Information System (INIS)

    Silva, R.M.; Aquino, F. de M.; Macedo, D.A. de; Sa, A.M.; Galvao, G.O.

    2016-01-01

    Fuel cells are electrochemical devices that convert chemical energy into electrical energy. These devices are basically divided into interconnectors, electrolyte, anode, and cathode. Recently, studies of improvements in microstructural and morphological properties of calcium cobaltate (Ca_3Co_4O_9, C349) has been made regarding its potential use as SOFC cathode for intermediate temperature. Gelatin has proven to be effective as a polymerizing agent in the synthesis of nanocrystalline materials. This work reports the synthesis and characterization of the C349 cathode using commercial gelatin. The structural properties of the material were determined by X-ray diffraction (XRD). Morphological characterization was performed by scanning electron microscopy (SEM). The results showed the formation of the crystalline phase at 900 °C, indicating the effectiveness of the gelatin in the preparation of cathodes for SOFC. (author)

  13. Ag as an alternative for Ni in direct hydrocarbon SOFC anodes

    Energy Technology Data Exchange (ETDEWEB)

    Cantos-Gomez, A.; Van Duijn, J. [Instituto de Energias Renovables, Universidad de Castilla La Mancha, Paseo de la Investigacion 1, 02006 Albacete (Spain); Ruiz-Bustos, R. [Instituto de Energias Renovables, Parque Cientifico y Tecnologico de Albacete, Paseo de la Investigacion 1, 02006 Albacete (Spain)

    2011-02-15

    Ag has been shown to be a good metal for SOFC anode cermets using CO fuel. Here we have expanded on the work reported by testing Ag-YSZ cermets against different hydrocarbon based fuel (H{sub 2} and CH{sub 4}). This study shows that while Ag is a good current collector, it alone does not have the required catalytic activity for the direct oxidation of hydrocarbon based fuels needed to be used in SOFC anodes. As such an additional catalytic material (e.g. CeO{sub 2}) needs to be present when using fuels other then CO. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Effect of load transients on SOFC operation—current reversal on loss of load

    Science.gov (United States)

    Gemmen, Randall S.; Johnson, Christopher D.

    The dynamics of solid oxide fuel cell (SOFC) operation have been considered previously, but mainly through the use of one-dimensional codes applied to co-flow fuel cell systems. In this paper several geometries are considered, including cross-flow, co-flow, and counter-flow. The details of the model are provided, and the model is compared with some initial experimental data. For parameters typical of SOFC operation, a variety of transient cases are investigated, including representative load increase and decrease and system shutdown. Of particular note for large load decrease conditions (e.g., shutdown) is the occurrence of reverse current over significant portions of the cell, starting from the moment of load loss up to the point where equilibrated conditions again provide positive current. Consideration is given as to when such reverse current conditions might most significantly impact the reliability of the cell.

  15. Hydrogen consumption and power density in a co-flow planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Ben Moussa, Hocine; Zitouni, Bariza [Laboratoire d' etude des systemes energetiques industriels (LESEI), Universite de Batna, Batna (Algeria); Oulmi, Kafia [Laboratoire de chimie et de chimie de l' environnement, Universite de Batna, Batna (Algeria); Mahmah, Bouziane; Belhamel, Maiouf [CDER, BP. 62 Route de l' Observatoire. Bouzareah. Alger (Algeria); Mandin, Philippe [Centre de Developpement des Energies Renouvelables (CDER), LECA, UMR 7575 CNRS-ENSCP Paris 6 (France)

    2009-06-15

    In the present work, power density and hydrogen consumption in a co-flow planar solid oxide fuel cell (SOFC) are studied according to the inlet functional parameters; such as the operational temperature, the operational pressure, the flow rates and the mass fractions of the species. Furthermore, the effect of the cell size is investigated. The results of a zero and a one-dimensional numerical electro-dynamic model predict the remaining quantity of the fed hydrogen at the output of the anode flow channel. The remaining hydrogen quantities and the SOFC's power density obtained are discussed as a function of the inlet functional parameters, the geometrical configuration of the cell and several operating cell voltages values. (author)

  16. Preparation of thin layer materials with macroporous microstructure for SOFC applications

    International Nuclear Information System (INIS)

    Marrero-Lopez, D.; Ruiz-Morales, J.C.; Pena-Martinez, J.; Canales-Vazquez, J.; Nunez, P.

    2008-01-01

    A facile and versatile method using polymethyl methacrylate (PMMA) microspheres as pore formers has been developed to prepare thin layer oxide materials with controlled macroporous microstructure. Several mixed oxides with fluorite and perovskite-type structures, i.e. doped zirconia, ceria, ferrites, manganites, and NiO-YSZ composites have been prepared and characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption and mercury porosimetry. The synthesised materials are nanocrystalline and present a homogeneous pore distribution and relatively high specific surface area, which makes them interesting for SOFC and catalysis applications in the intermediate temperature range. - Graphical abstract: Thin films materials of mixed oxides with potential application in SOFC devices have been prepared with macroporous microstructure using PMMA microspheres as pore formers. Display Omitted

  17. LaCrO{sub 3}-dispersed Cr for metallic interconnect of planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Song, Rak-Hyun; Shin, Dong Ryul [Korea Institute of Energy Research, Taejon (Korea, Republic of); Dokiya, Masayuki [National Institute of Materials and Chemical Research, Ibaraki (Japan)

    1996-12-31

    In the planar SOFC, the interconnect materials plays two roles as an electrical connection and as a gas separation plate in a cell stack. The interconnect materials must be chemically stable in reducing and oxidizing environments, and have high electronic conductivity, high thermal conductivity, matching thermal expansion with an electrolyte, high mechanical strength, good fabricability, and gas tightness. Lanthanum chromite so far has been mainly used as interconnect materials in planar SOFC. However, the ceramic materials are very weak in mechanical strength and have poor machining property as compared with metal. Also the metallic materials have high electronic conductivity and high thermal conductivity. Recently some researchers have studied metallic interconnects such as Al{sub 2}O{sub 3}/Inconel 600 cermet, Ni-20Cr coated with (LaSr)CoO{sub 3}, and Y{sub 2}O{sub 3-} or La{sub 2}O{sub 3}-dispersed Cr alloy. These alloys have still some problems because Ni-based alloys have high thermal expansion, the added Al{sub 2}O{sub 3}, Y{sub 2}O{sub 3} and La{sub 2}O{sub 3} to metals have no electronic conductivity, and the oxide formed on the surface of Cr alloy has high volatility. To solve these problems, in this study, LaCrO{sub 3}-dispersed Cr for metallic interconnect of planar SOFC was investigated. The LaCrO{sub 3}-dispersed Cr can be one candidate of metallic interconnect because LaCrO{sub 3} possesses electronic conductivity and Cr metal has relatively low thermal expansion. The content of 25 vol.% LaCrO{sub 3} Was selected on the basis of a theoretically calculated thermal expansion. The thermal expansion, electrical and oxidation properties were examined and the results were discussed as related to SOFC requirements.

  18. Total cost of ownership of CHP SOFC systems: Effect of installation context

    International Nuclear Information System (INIS)

    Arduino, Francesco; Santarelli, Massimo

    2016-01-01

    Solid oxide fuel cells (SOFC) are one of the most interesting between the emerging technologies for energy production. Although some information about the production cost of these devices are already known, their operational cost has not been studied yet with sufficient accuracy. This paper presents a life cycle cost (LCC) analysis of CHP (combined heat and power) SOFC systems performed in hospitals located in various cities of the US and one in Italy. In this study the strong effects of the installation context will be analyzed using a customized use phase model for each location. The cost effectiveness of these devices has been proved without credits in Mondovi (IT), New York (NY) and Minneapolis (MN) where the payback time goes from 10 to 7 years. Considering the credits, it is possible to obtain economic feasibility also in Chicago (IL) and reduce the payback for other cities to values from 4 to 6 years. In other cities like Phoenix (AZ) and Houston (TX) the payback can’t be reached in any case. The life cycle impact assessment analysis has shown how, even in the cities with cleaner electricity grid, there is a reduction in the emissions of both greenhouse gases and pollutants. - Highlights: •Life cycle cost analysis has been performed for CHP SOFC systems. •The strong effects of the installation context have been analyzed. •Economic feasibility has been proven in new york, Minneapolis and Mondovi. •Economic feasibility can’t be reached in phoenix and Houston. •SOFC always provide a reduction in the emissions of greenhouse gases and pollutant.

  19. The design of stationary and mobile solid oxide fuel cell-gas turbine systems

    Science.gov (United States)

    Winkler, Wolfgang; Lorenz, Hagen

    A general thermodynamic model has shown that combined fuel cell cycles may reach an electric-efficiency of more than 80%. This value is one of the targets of the Department of Energy (DOE) solid oxide fuel cell-gas turbine (SOFC-GT) program. The combination of a SOFC and GT connects the air flow of the heat engine and the cell cooling. The principle strategy in order to reach high electrical-efficiencies is to avoid a high excess air for the cell cooling and heat losses. Simple combined SOFC-GT cycles show an efficiency between 60 and 72%. The combination of the SOFC and the GT can be done by using an external cooling or by dividing the stack into multiple sub-stacks with a GT behind each sub-stack as the necessary heat sink. The heat exchangers (HEXs) of a system with an external cooling have the benefit of a pressurization on both sides and therefore, have a high heat exchange coefficient. The pressurization on both sides delivers a low stress to the HEX material. The combination of both principles leads to a reheat (RH)-SOFC-GT cycle that can be improved by a steam turbine (ST) cycle. The first results of a study of such a RH-SOFC-GT-ST cycle indicate that a cycle design with an efficiency of more than 80% is possible and confirm the predictions by the theoretical thermodynamic model mentioned above. The extremely short heat-up time of a thin tubular SOFC and the market entrance of the micro-turbines give the option of using these SOFC-GT designs for mobile applications. The possible use of hydrocarbons such as diesel oil is an important benefit of the SOFC. The micro-turbine and the SOFC stack will be matched depending on the start-up requirements of the mobile system. The minimization of the volume needed is a key issue. The efficiency of small GTs is lower than the efficiency of large GTs due to the influence of the leakage within the stages of GTs increasing with a decreasing size of the GT. Thus, the SOFC module pressure must be lower than in larger

  20. Effect of interlayer on structure and performance of anode-supported SOFC single cells

    International Nuclear Information System (INIS)

    Eom, Tae Wook; Yang, Hae Kwang; Kim, Kyung Hwan; Yoon, Hyon Hee; Kim, Jong Sung; Park, Sang Joon

    2008-01-01

    To lower the operating temperatures in solid oxide fuel cell (SOFC) operations, anode-supported SOFC single cells with a single dip-coated interlayer were fabricated and the effect of the interlayer on the electrolyte structure and the electrical performance was investigated. For the preparation of SOFC single cells, yttria-stabilized zirconia (YSZ) electrolyte, NiO-YSZ anode, and 50% YSZ-50% strontium-doped lanthanum manganite (LSM) cathode were used. In order to characterize the cells, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were utilized and the gas (air) permeability measurements were conducted for gas tightness estimation. When the interlayer was inserted onto NiO-YSZ anode, the surface roughness of anode was diminished by about 40% and dense crack-free electrolytes were obtained. The electrical performance was enhanced remarkably and the maximum power density was 0.57 W/cm 2 at 800 deg. C and 0.44 W/cm 2 at 700 deg. C. On the other hand, the effect of interlayer on the gas tightness was negligible. The characterization study revealed that the enhancement in the electrical performance was mainly attributed to the increase of ion transmission area of anode/electrolyte interface and the increase of ionic conductivity of dense crack-free electrolyte layer

  1. Interfacial layers in tape cast anode-supported doped lanthanum gallate SOFC elements

    Energy Technology Data Exchange (ETDEWEB)

    Maffei, N.; De Silveira, G. [Materials Technology Laboratory, Natural Resources Canada, CANMET, 405 Rochester Street, Ottawa, Ontario (Canada) K1A OG3

    2003-04-01

    Lanthanum gallate doped with strontium and magnesium (LSGM) is a promising electrolyte system for intermediate temperature solid oxide fuel cells (SOFCs). The reported formation of interfacial layers in monolithic type SOFCs based on lanthanum gallate is of concern because of its impact on the performance of the fuel cell. Planar anode-supported SOFC elements (without the cathode) were prepared by the tape casting technique in order to determine the nature of the anode/electrolyte interface after sintering. Two anode systems were studied, one a NiO-CeO{sub 2} cermet, and the other, a modified lanthanum gallate anode containing manganese. Sintering studies were conducted at 1250, 1300, 1350, 1400 and 1450 C to determine the effect of temperature on the interfacial characteristics. Scanning electron microscopy (SEM) revealed a significant diffusion of Ni from the NiO-CeO{sub 2} anode resulting in the formation of an interfacial layer regardless of sintering temperature. Significant La diffusion from the electrolyte into the anode was also observed. In the case of the modified lanthanum gallate anode containing manganese, there was no interfacial layer formation, but a significant diffusion of Mn into the electrolyte was observed.

  2. Probing Temperature Inside Planar SOFC Short Stack, Modules, and Stack Series

    Science.gov (United States)

    Yu, Rong; Guan, Wanbing; Zhou, Xiao-Dong

    2017-02-01

    Probing temperature inside a solid oxide fuel cell (SOFC) stack lies at the heart of the development of high-performance and stable SOFC systems. In this article, we report our recent work on the direct measurements of the temperature in three types of SOFC systems: a 5-cell short stack, a 30-cell stack module, and a stack series consisting of two 30-cell stack modules. The dependence of temperature on the gas flow rate and current density was studied under a current sweep or steady-state operation. During the current sweep, the temperature inside the 5-cell stack decreased with increasing current, while it increased significantly at the bottom and top of the 30-cell stack. During a steady-state operation, the temperature of the 5-cell stack was stable while it was increased in the 30-cell stack. In the stack series, the maximum temperature gradient reached 190°C when the gas was not preheated. If the gas was preheated and the temperature gradient was reduced to 23°C in the stack series with the presence of a preheating gas and segmented temperature control, this resulted in a low degradation rate.

  3. Simulation and Parametric Analysis of a Hybrid SOFC-Gas Turbine Power Generation System

    International Nuclear Information System (INIS)

    Hassan, A.M.; Fahmy

    2004-01-01

    Combined SOFC-Gas Turbine Power Generation Systems are aimed to increase the power and efficiency obtained from the technology of using high temperature fuel cells by integrating them with gas turbines. Hybrid systems are considered in the last few years as one of the most promising technologies to obtain electric energy from the natural gas at very high efficiency with a serious potential for commercial use. The use of high temperature allows internal reforming for natural gas and thus disparity of fuel composition is allowed. Also air preheating is performed thanks to the high operating cell temperature as a task of energy integration. In this paper a modeling approach is presented for the fuel cell-gas turbine hybrid power generation systems, to obtain the sofc output voltage, power, and the overall hybrid system efficiency. The system has been simulated using HYSYS, the process simulation software to help improving the process understanding and provide a quick system solution. Parametric analysis is also presented in this paper to discuss the effect of some important SOFC operating parameters on the system performance and efficiency

  4. Development of a Low Cost 10kW Tubular SOFC Power System

    Energy Technology Data Exchange (ETDEWEB)

    Bessette, Norman [Acumentrics Corporation, Westwood, MA (United States); Litka, Anthony [Acumentrics Corporation, Westwood, MA (United States); Rawson, Jolyon [Acumentrics Corporation, Westwood, MA (United States); Schmidt, Douglas [Acumentrics Corporation, Westwood, MA (United States)

    2013-06-06

    The DOE program funded from 2003 through early 2013 has brought the Acumentrics SOFC program from an early stage R&D program to an entry level commercial product offering. The development work started as one of the main core teams under the DOE Solid State Energy Conversion Alliance (SECA) program administered by the National Energy Technology Laboratory (NETL) of the DOE. During the first phase of the program, lasting approximately 3-4 years, a 5kW machine was designed, manufactured and tested against the specification developed by NETL. This unit was also shipped to NETL for independent verification testing which validated all of the results achieved while in the laboratory at Acumentrics. The Acumentrics unit passed all criteria established from operational stability, efficiency, and cost projections. Passing of the SECA Phase I test allowed the program to move into Phase II of the program. During this phase, the overall objective was to further refine the unit meeting a higher level of performance stability as well as further cost reductions. During the first year of this new phase, the NETL SECA program was refocused towards larger size units and operation on coal gasification due to the severe rise in natural gas prices and refocus on the US supply of indigenous coal. At this point, the program was shifted to the U.S. DOE’s Energy Efficiency and Renewable Energy (EERE) division located in Golden, Colorado. With this shift, the focus remained on smaller power units operational on gaseous fuels for a variety of applications including micro combined heat and power (mCHP). To achieve this goal, further enhancements in power, life expectancy and reductions in cost were necessary. The past 5 years have achieved these goals with machines that can now achieve over 40% electrical efficiency and field units that have now operated for close to a year and a half with minimal maintenance. The following report details not only the first phase while under the SECA program

  5. High-velocity DC-VPS for diffusion and protecting barrier layers in solid oxide fuel cells (SOFCs)

    Science.gov (United States)

    Henne, R. H.; Franco, T.; Ruckdäschel, R.

    2006-12-01

    High-temperature fuel cells of the solid oxide fuel cell (SOFC) type as direct converter of chemical into electrical energy show a high potential for reducing considerably the specific energy consumption in different application fields. Of particular interest are advanced lightweight planar cells for electricity supply units in cars and other mobile systems. Such cells, in one new design, consist mainly of metallic parts, for example, of ferrite steels. These cells shall operate in the temperature range of 700 to 800 °C where oxidation and diffusion processes can be of detrimental effect on cell performance for long-term operation. Problems arise in particular by diffusion of chromium species from the interconnect or the cell containment into the electrolyte/cathode interface forming insulating phases and by the mutual diffusion of substrate and anode material, for example, iron and chromium from the ferrite into the anode and nickel from the anode into the ferrite, which in both cases reduces performance and system lifetime. Additional intermediate layers of perovskite-type material, (e.g., doped LaCrO3) applied with high-velocity direct-current vacuum plasma spraying (DC-VPS) can reduce such effects considerably if they are stable and of high electronic conductivity.

  6. Danish strategy for developing SOFC fuel cells 2010-2020; Dansk strategi for udvikling af SOFC-braendselsceller 2010-2020

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.; Linderoth, S. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Themsen, J. (Dantherm Power A/S, Hobro (Denmark)); Richter, A.B.; Hansen, Hakon J.; Holm-Larsen, H.; Andersen, Claus V. (Topsoe Fuel Cell A/S, Lyngby (Denmark))

    2010-09-15

    SOFC fuel cells are a promising technology for efficient production of electricity. The technology is expected to contribute very significantly to climate and environmental goals, security of supply of energy, increased employment and exports. Denmark has a very strong technology position within the SOFC area based on years of cooperation between Topsoe Fuel Cell and Risoe DTU as well as a later developed relationship with Dantherm Power. The Danish players have received more than DKK 250 million in public funding. With this support and the players' own funding (approx. two times higher than public support), the players managed over the past 10 years to bring development of SOFC technology significantly closer to the market. This strategy has been prepared by the Danish players in the field and gives a picture of the required overall development needs in the coming years. Technology development has reached the stage where in the coming years demonstrations on a larger scale have to be launched. The focus is basically on three valuable market segments: micro power and heat, auxiliary power for mobile applications, and decentralized power and CHP, which all have a great potential for market penetration internationally. When the market is established in one or more of these segments, other business opportunities must be explored for other applications based on the established technological platform. The road to commercialization is a long process that begins with demonstrations and later introduction of commercial products. The primary actors are currently the largest companies and institutions but as the number of produced fuel cell units increases, job creation with subcontractors and other directly related businesses and research centres will increase. A conservative estimate of market size worldwide is 2-4 GW of installed capacity per. year representing an annual turnover of 15-30 billion DKK and 10.000-20.000 more jobs. The export ratio is expected to exceed

  7. Impedance of SOFC electrodes: A review and a comprehensive case study on the impedance of LSM:YSZ cathodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Hjelm, Johan

    2014-01-01

    It was shown through a comprehensive impedance spectroscopy study that the impedance of the classic composite LSM:YSZ (lanthanum strontium manganite and yttria stabilized zirconia) solid oxide fuel cell (SOFC) cathode can be described well with porous electrode theory. Furthermore, it was illustr......It was shown through a comprehensive impedance spectroscopy study that the impedance of the classic composite LSM:YSZ (lanthanum strontium manganite and yttria stabilized zirconia) solid oxide fuel cell (SOFC) cathode can be described well with porous electrode theory. Furthermore......, it was illustrated through a literature review on SOFC electrodes that porous electrode theory not only describes the classic LSM:YSZ SOFC cathode well, but SOFC electrodes in general. The extensive impedance spectroscopy study of LSM:YSZ cathodes consisted of measurements on cathodes with three different sintering...... temperatures and hence different microstructures and varying degrees of LSM/YSZ solid state interactions. LSM based composite cathodes, where YSZ was replaced with CGO was also studied in order to acquire further knowledge on the chemical compatibility between LSM and YSZ. All impedance measurements were...

  8. Synthesis of modified calcium aluminate with lanthanum manganite (LSM) for possible use in solid oxide fuel cell (SOFC); Sintese de aluminato de calcio modificado com manganita de lantanio (LSM) para possivel utilizacao em celula combustivel de oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Veiga, F.C.T.; Jurado, J.; Sousa, V.C. de, E-mail: faili.cintia@gmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Escola de Engenharia. Departamento de Materiais; Cava, S.S. [Universidade Federal de Pelotas, RS (Brazil)

    2016-07-01

    The fuel cells solid oxide (SOFC) is made up of three basic elements: two electrodes, the anode and cathode and a conductive electrolyte ions. The objective of this work consists of calcium aluminate synthesis modified LSM in a 1: 1 by combustion synthesis method with a view to its use as a cathode in SOFC. The characterization of the post was carried out by the methods of XRD, TEM and EIS. After heat treatment at 1200°C/4 hours it was possible to obtain Ca0.5Sr1.5MnO4 and CaMnO2.56 phases. The material showed a semiconductor characteristics because with increasing temperature the electrical resistance value tends to decrease obtaining electrical conductivity greater than 10-6S / cm featuring an extrinsic semiconductor with an activation energy of 0.12. Therefore, with an activation energy value within the range of materials used for a SOFC cathodes. (author)

  9. SOFC solid oxide fuel cell power plants for the decentralised electric energy supply; SOFC-Brennstoffzellen-Kraftwerke fuer die dezentrale elektrische Energieversorgung

    Energy Technology Data Exchange (ETDEWEB)

    Fogang Tchonla, Etienne

    2012-07-01

    To use the fuel cell economically, the efficiency of the system must still be raised so that it can be set up in the market. Within the scope of analysis on this topic, a 120-kW-SOFC-demonstration power plant was to be considered. Since not enough information about the demonstration power plant from the operator was available for the investigation, we had to calculate with the help of the known technical data of similar power plants. After that a model was build and simulated by means of MATLAB/Simulink. Before that the single power plant components were being described. Two of them (the boost converter as well as the inverter) were looked at more thoroughly. As a result of the analysis, it was found that a standard inverter which had been conceived for other applications, for example, Photovoltaic or Wind Power can also be used for fuel cells. Unfortunately, this was not the case for the added boost converter. It had to be precisely conceived for the used fuel cell type. After this discovery information was won for the realization of a 1-MW-Fuel Cell Power Plant. The topology of the 1-MW-power plant was fixed on the basis of the 120-kW-system. A parallel connection of eight 120-kW SOFC-fuel cell aggregates is intended, as well as a connection at the outlet side 120-kW boost converters. A standard inverter with 1 MW electrical power as well as a 1-MVA-transformer could be used for the realization of the 1-MW-power plant. The binding of the power plant in the three-phase current network was examined in view of the norms, laws and connection conditions. Beside the distinction of the operating forms of the power plant (parallel or isolated operation) the security of the plant was emphasized with regard to quick fault recognition, safe supply line isolation in the fault case as well as a compliance of the prescribed regulations. To verify the calculated results as well as the provided models, a 10-kW-labor sample was built and examined in the lab. This experimental

  10. Fracture-mechanical analysis of metal/ceramic composites for applications in high-temperature fuel cells (SOFC); Bruchmechanische Untersuchung von Metall/Keramik-Verbunsystemen fuer die Anwendung in der Hochtemperaturbrennstoffzelle (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, Bernd Josef

    2008-08-25

    The author investigated the deformation and damage behaviour of soldered ceramic/metal joints in SOFC stacks, using thermochemical methods. Methods for analyzing sandwich systems and for mechanical characterization of joints were adapted and modified in order to provide fundamental understanding of the mechanical properties of soldered joints. [German] In dieser Arbeit wurde das Verformungs- und Schaedigungsverhalten von Keramik/ Metall-Loetverbindungen fuer SOFC-Stacks thermomechanisch untersucht. Verfahren zur Analyse von Schichtsystemen und fuer die mechanische Charakterisierung von Fuegeverbindungen wurden adaptiert und weiterentwickelt, um zu einem grundlegenden Verstaendnis der mechanischen Eigenschaften von Loetverbindungen zu gelangen.

  11. Synthesis of modified calcium aluminate with lanthanum manganite (LSM) for possible use in solid oxide fuel cell (SOFC)

    International Nuclear Information System (INIS)

    Veiga, F.C.T.; Jurado, J.; Sousa, V.C. de

    2016-01-01

    The fuel cells solid oxide (SOFC) is made up of three basic elements: two electrodes, the anode and cathode and a conductive electrolyte ions. The objective of this work consists of calcium aluminate synthesis modified LSM in a 1: 1 by combustion synthesis method with a view to its use as a cathode in SOFC. The characterization of the post was carried out by the methods of XRD, TEM and EIS. After heat treatment at 1200°C/4 hours it was possible to obtain Ca0.5Sr1.5MnO4 and CaMnO2.56 phases. The material showed a semiconductor characteristics because with increasing temperature the electrical resistance value tends to decrease obtaining electrical conductivity greater than 10-6S / cm featuring an extrinsic semiconductor with an activation energy of 0.12. Therefore, with an activation energy value within the range of materials used for a SOFC cathodes. (author)

  12. Direct Utilization of Liquid Fuels in SOFC for Portable Applications: Challenges for the Selection of Alternative Anodes

    Directory of Open Access Journals (Sweden)

    Massimiliano Cimenti

    2009-06-01

    Full Text Available Solid oxide fuel cells (SOFC have the advantage of being able to operate with fuels other than hydrogen. In particular, liquid fuels are especially attractive for powering portable applications such as small power generators or auxiliary power units, in which case the direct utilization of the fuel would be convenient. Although liquid fuels are easier to handle and transport than hydrogen, their direct use in SOFC can lead to anode deactivation due to carbon formation, especially on traditional nickel/yttria stabilized zirconia (Ni/YSZ anodes. Significant advances have been made in anodic materials that are resistant to carbon formation but often these materials are less electrochemically active than Ni/YSZ. In this review the challenges of using liquid fuels directly in SOFC, in terms of gas-phase and catalytic reactions within the anode chamber, will be discussed and the alternative anode materials so far investigated will be compared.

  13. Fabrication of Sr- and Co-doped lanthanum chromite interconnectors for SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Setz, L.F.G. [Departamento de Engenharia de Materiais, Universidade Federal de Sao Carlos - DEMa/UFSCar (Brazil); Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN (Brazil); Santacruz, I. [Departamento de Quimica Inorganica, Cristalografia y Mineralogia, Universidad de Malaga, 29071 Malaga (Spain); Colomer, M.T., E-mail: tcolomer@icv.csic.es [Instituto de Ceramica y Vidrio, ICV (CSIC), 28049 Madrid (Spain); Mello-Castanho, S.R.H. [Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN (Brazil); Moreno, R. [Instituto de Ceramica y Vidrio, ICV (CSIC), 28049 Madrid (Spain)

    2011-07-15

    Graphical abstract: FESEM micrographs of the fresh fracture surfaces for the La{sub 0.80}Sr{sub 0.20}Cr{sub 0.92}Co{sub 0.08}O{sub 3} sintered specimens cast from optimised suspensions with 13.5, 15 and 17.5 vol.% solids loading. Aqueous suspensions were prepared using ammonium polyacrylate (PAA) as dispersant and tetramethylammonium hydroxide (TMAH) to assure a basic pH and providing stabilization. Sintering of the green discs was performed in air at 1600 {sup o}C for 4 h. Highlights: {yields} Optimum casting slips were achieved with 3 wt.% of ammonium polyacrylate and 1 wt.% of tetramethylammonium hydroxide. -- Abstract: Many studies have been performed dealing with the processing conditions of electrodes and electrolytes in solid oxide fuel cells (SOFCs). However, the processing of the interconnector material has received less attention. Lanthanum chromite (LaCrO{sub 3}) is probably the most studied material as SOFCs interconnector. This paper deals with the rheology and casting behaviour of lanthanum chromite based materials to produce interconnectors for SOFCs. A powder with the composition La{sub 0.80}Sr{sub 0.20}Cr{sub 0.92}Co{sub 0.08}O{sub 3} was obtained by combustion synthesis. Aqueous suspensions were prepared to solids loading ranging from 8 to 17.5 vol.%, using ammonium polyacrylate (PAA) as dispersant and tetramethylammonium hydroxide (TMAH) to assure a basic pH and providing stabilization. The influence of the additives concentrations and suspension ball milling time were studied. Suspensions prepared with 24 h ball milling, with 3 wt.% and 1 wt.% of PAA and TMAH, respectively, yielded the best conditions for successful slip casting. Sintering of the green discs was performed in air at 1600 {sup o}C for 4 h leading to relatively dense materials.

  14. Effect of ionic conductivity of zirconia electrolytes on polarization properties of various electrodes in SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Masahiro; Uchida, Hiroyuki; Yoshida, Manabu [Yamanashi Univ., Kofu (Japan)

    1996-12-31

    Solid oxide fuel cells (SOFCs) have been intensively investigated because, in principle, their energy conversion efficiency is fairly high. Lowering the operating temperature of SOFCs from 1000{degrees}C to around 800{degrees}C is desirable for reducing serious problems such as physical and chemical degradation of the constructing materials. The object of a series of the studies is to find a clue for achieving higher electrode performances at a low operating temperature than those of the present level. Although the polarization loss at electrodes can be reduced by using mixed-conducting ceria electrolytes, or introducing the mixed-conducting (reduced zirconia or ceria) laver on the conventional zirconia electrolyte surface, no reports are available on the effect of such an ionic conductivity of electrolytes on electrode polarizations. High ionic conductivity of the electrolyte, of course, reduces the ohmic loss. However, we have found that the IR-free polarization of a platinum anode attached to zirconia electrolytes is greatly influenced by the ionic conductivity, {sigma}{sub ion}, of the electrolytes used. The higher the {sigma}{sub ion}, the higher the exchange current density, j{sub 0}, for the Pt anode in H{sub 2} at 800 {approximately} 1000{degrees}C. It was indicated that the H{sub 2} oxidation reaction rate was controlled by the supply rate of oxide ions through the Pt/zirconia interface which is proportional to the {sigma}{sub ion}. Recently, we have proposed a new concept of the catalyzed-reaction layers which realizes both high-performances of anodes and cathodes for medium-temperature operating SOFCs. We present the interesting dependence of the polarization properties of various electrodes (the SDC anodes with and without Ru microcatalysts, Pt cathode, La(Sr)MnO{sub 3} cathodes with and without Pt microcatalysts) on the {sigma}{sub ion} of various zirconia electrolytes at 800 {approximately} 1000{degrees}C.

  15. Evaluation of nickel and copper catalysts in biogas reforming for hydrogen production in SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Leonardo Alves; Martins, Andre Rosa; Rangel, Maria do Carmo, E-mail: mcarmov@ufba.br [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Grupo de Estudos em Cinetica e Catalise; Ballarini, Adriana; Maina, Silvia [Instituto de Investigaciones en Catalisis Y Petroquimica Ing. Jose Miguel Parera (INCAPE), Santa Fe (Argentina)

    2017-01-15

    The solid oxide fuel cells (SOFC) enable the efficient generation of clean energy, fitting the current requirements of the growing demand for electricity and for the environment preservation. When powered with biogas (from digesters of municipal wastes), the SOFCs also contribute to reduce the environmental impact of these wastes. The most suitable route to produce hydrogen inside SOFC from biogas is through dry reforming but the catalyst is easily deactivated by coke, because of the high amounts of carbon in the stream. A promising way to overcome this drawback is by adding a second metal to nickel-based catalysts. Aiming to obtain active, selective and stable catalysts for biogas dry reforming, solids based on nickel (15%) and copper (5%) supported on aluminum and magnesium oxide were studied in this work. Samples were prepared by impregnating the support with nickel and copper nitrate, followed by calcination at 500, 600 and 800 deg C. It was noted that all solids were made of nickel oxide, nickel aluminate and magnesium aluminate but no copper compound was found. The specific surface areas did not changed with calcination temperature but the nickel oxide average particles size increased. The solids reducibility decreased with increasing temperature. All catalysts were active in methane dry reforming, leading to similar conversions but different selectivities to hydrogen and different activities in water gas shift reaction (WGSR). This behavior was assigned to different interactions between nickel and copper, at different calcination temperatures. All catalysts were active in WGSR, decreasing the hydrogen to carbon monoxide molar ratio and producing water. The catalyst calcined at 500 deg C was the most promising one, leading to the highest hydrogen yield, besides the advantage of being produced at the lowest calcination temperature, requiring less energy in its preparation. (author)

  16. Evaluation of nickel and copper catalysts in biogas reforming for hydrogen production in SOFC

    International Nuclear Information System (INIS)

    Silva, Leonardo Alves; Martins, Andre Rosa; Rangel, Maria do Carmo

    2017-01-01

    The solid oxide fuel cells (SOFC) enable the efficient generation of clean energy, fitting the current requirements of the growing demand for electricity and for the environment preservation. When powered with biogas (from digesters of municipal wastes), the SOFCs also contribute to reduce the environmental impact of these wastes. The most suitable route to produce hydrogen inside SOFC from biogas is through dry reforming but the catalyst is easily deactivated by coke, because of the high amounts of carbon in the stream. A promising way to overcome this drawback is by adding a second metal to nickel-based catalysts. Aiming to obtain active, selective and stable catalysts for biogas dry reforming, solids based on nickel (15%) and copper (5%) supported on aluminum and magnesium oxide were studied in this work. Samples were prepared by impregnating the support with nickel and copper nitrate, followed by calcination at 500, 600 and 800 deg C. It was noted that all solids were made of nickel oxide, nickel aluminate and magnesium aluminate but no copper compound was found. The specific surface areas did not changed with calcination temperature but the nickel oxide average particles size increased. The solids reducibility decreased with increasing temperature. All catalysts were active in methane dry reforming, leading to similar conversions but different selectivities to hydrogen and different activities in water gas shift reaction (WGSR). This behavior was assigned to different interactions between nickel and copper, at different calcination temperatures. All catalysts were active in WGSR, decreasing the hydrogen to carbon monoxide molar ratio and producing water. The catalyst calcined at 500 deg C was the most promising one, leading to the highest hydrogen yield, besides the advantage of being produced at the lowest calcination temperature, requiring less energy in its preparation. (author)

  17. Temperature and flow distribution in planar SOFC stacks

    Directory of Open Access Journals (Sweden)

    Monica Østenstad

    1995-07-01

    Full Text Available Simulation of a planar Solid Oxide Fuel Cell stack requires the solution of the mass balances of the chemical species, the energy balances, the charge balance and the channel flow equations in order to compute the species concentrations, the temperature distributions, the current density and the channel flows. The unit cell geometry can be taken into account by combining detailed modeling of a unit cell with a homogenized model of a whole stack. In this study the effect of the asymmetric temperature distribution on the channel flows in a conventional cross-flow design has been investigated. The bidirectional cross-flow design is introduced, for which we can show more directional temperature and flow distributions.

  18. Shape distortion and thermo-mechanical properties of SOFC components from green tape to sintering body

    DEFF Research Database (Denmark)

    Teocoli, Francesca; Ni, De Wei; Tadesse Molla, Tesfaye

    due to binder burn out, differential shrinkage behavior and to a potential interfacial reaction between the two materials. To analyze the phenomena, shrinkage of SOFC components single layers and bilayered samples were measured insitu by optical dilatometer. The densification mismatch stress, due...... to the strain rate difference between materials, was calculated using Cai’s model. Camber (curvature) development for in situ co-firing of a bi-layer ceramic green tape has been investigated. Analysis of shape evolution from green to sintered body can be carried out by the thermo-mechanical analysis techniques....

  19. Thermoeconomic Analysis Of a Gasification Plant Fed By Woodchips And Integrated With SOFC And STIG Cycles

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Rokni, Masoud

    2013-01-01

    of the influence of SOFC stack cost on the generation cost is also presented. In order to discuss the investment cost, an economic analysis has been carried out by involving main parameters such as Net Present Value (NPV), Internal Rate of Return (IRR), Time of Return of Investment (TIR) are calculated...... above 53% and 43% respectively which are significantly greater than conventional 10 MWe plants fed by biomass. Thermo-economic analysis provides an average cost of electricity for best performing layouts close to 6.4 and 9.4 c€/kWe which is competitive within the market. A sensitivity analysis...

  20. The mechanism behind redox instability of anodes in high-temperature SOFCs

    DEFF Research Database (Denmark)

    Klemensø, Trine; Chung, Charissa; Larsen, Peter Halvor

    2005-01-01

    Bulk expansion of the anode upon oxidation is considered to be responsible for the lack of redox stability in high-temperature solid oxide fuel cells (SOFCs). The bulk expansion of nickel-yttria stabilized zirconia (YSZ) anode materials was measured by dilatometry as a function of sample geometry......, ceramic component, temperature, and temperature cycling. The strength of the ceramic network and the degree of Ni redistribution appeared to be key parameters of the redox behavior. A model of the redox mechanism in nickel-YSZ anodes was developed based on the dilatometry data and macro...

  1. Reversibility of the SOFC for the hydrogen production by high temperature electrolysis

    International Nuclear Information System (INIS)

    Brisse, A.; Marrony, M.; Perednis, D.; Schefold, J.; Jose-Garcia, M.; Zahid, M.

    2007-01-01

    The behaviour of two SOFC cells in electrolysis mode is studied. The performances of these solid oxide cells, reversible at 800 C and for current densities between 0 and -0.42 A/cm 2 , are presented. A weaker polarisation resistance has been measured for the cell containing a mixed conductor as oxygen electrode. For each cell, a limitation by gaseous diffusion has been observed under current. This phenomenon appears for current densities which are higher for the mixed conductor cell as oxygen electrode. (O.M.)

  2. Thermodynamic and thermoeconomic analysis of a system with biomass gasification, solid oxide fuel cell (SOFC) and Stirling engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    Thermodynamic and thermoeconomic investigations of a small-scale integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120kWe have been performed. Woodchips are used as gasification feedstock to produce syngas......Wh. Furthermore, hot water is considered as a by-product, and the cost of hot water is found to be 0.0214$/kWh. When compared to other renewable systems of similar scales, this result shows that if both SOFC and Stirling engine technology enter the commercialization phase, then they can deliver electricity...

  3. NiO/YSZ Reduction for SOFC/SOEC Studied In Situ by Environmental Transmission Electron Microscopy

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Agersted, Karsten; Hansen, Karin Vels

    2014-01-01

    SOFCs/SOECs are typically composed of ceramic materials, which are highly complex at the nano-scale. Scanning and transmission electron microscopy (SEM and TEM) are routinely applied for studying these nano-scaled structures post mortem, but only few SOFC/SOEC studies have applied environmental T...... and constant temperature ramping rate of 1°C/min. The NiO observed in the first image at 320°C is dense. From the lower left corner a front of porous Ni is progressing until full reduction at 340°C. [Formula]...

  4. Electrochemical performances of proton-conducting SOFC with La-Sr-Fe-O cathode fabricated by electrophoretic deposition techniques

    International Nuclear Information System (INIS)

    Asamoto, Makiko; Miyake, Shinji; Yonei, Yuka; Yamaura, Hiroyuki; Yahiro, Hidenori

    2009-01-01

    The electrochemical performances of Proton-conducting SOFC with La 0.7 Sr 0.3 FeO 3 (LSF) cathode fabricated by the electrophoretic deposition (EPD) technique were investigated. The EPD technique provided the uniform layer of LSF cathode with constant thickness and can easily control the thickness by changing an applied voltage. The power density of the SOFC cell was dependent on the thickness of LSF cathode. The activation energy was measured to elucidate the rate-determining step for LSF cathode reaction. (author)

  5. Review of manufacturing processes for fabrication of SOFC components

    International Nuclear Information System (INIS)

    Stacey, B.; Badwal, S.P.S.; Foger, K.

    1998-01-01

    In order for fuel cell technology to be commercial, it must meet stringent criteria of reliability, life-time expectations and cost. While materials play an important role in determining these parameters, engineering design and manufacturing processes for fuel cell stack components are equally important. Manufacturing processes must be low cost and suitable for large volume production for the technology to be viable and competitive in the market place. Several processes suitable for the production of ceramic components used in solid oxide fuel cells as well as ceramic coating techniques required for the protection of some metal components have been described. Copyright (1998) Australasian Ceramic Society

  6. Sealing of ceramic SOFC-components with glass seals; Fuegen von keramischen Komponenten der Hochtemperatur-Brennstoffzellen mittels Glas- und Glaskeramikloten

    Energy Technology Data Exchange (ETDEWEB)

    Schillig, Cora

    2012-07-10

    The solid oxide fuel cell (SOFC) converts chemical energy of a fuel directly into electrical energy. However, for the implementation of SOFC-technology in competition to conventional power plants costs have to be reduced. The use of an alternative tubular cell design without closed end would allow reducing costs during cell manufacturing. However, this change in design makes a gastight sealing inside the generator near the gas inlet necessary. Different ceramic materials with varying coefficients of thermal expansion have to be sealed gastight and electrical insulating at temperatures between 850 C and 1000 C to prevent the gases from mixing and an electrical shortcut between the cells. This work comprises analysis of commercially available glass and glass-ceramic systems manufactured by Schott Electronic Packaging, Areva T and D and Ferro Corporation. Additionally new developed sealing glass and glass-ceramic systems were investigated and all systems were characterized fundamentally for the use as sealing material in SOFC generators. Therefore different test assemblies and series were conducted. Essential characteristics of a suitable sealing system are a thermal expansion coefficient between 9,5 and 12 . 10{sup -6}K{sup -1}, a viscosity in the range between 10{sup 4} to 10{sup 6} dPa{sup *}s and a wetting angle smaller than 90 during the sealing process. Also unwanted chemical side reactions between the sealing partners must be prevented, because a change in the phase composition or the creation of new phases in the sealing material could endanger the stability of the seal. Heat cycles, particularly those during generator operation, cause deterioration of the sealing material and subsequent reduction in its ability to prevent mixing of the gases. Sealant leaks can drastically impact efficiency of the generator. In order to ensure optimum operation low leak rates around 2,3 . 10{sup -4} mbar l/sec/cm{sup 2} must be maintained. Especially glass and glass

  7. Carbon Tolerant Fuel Electrodes for Reversible Sofc Operating on Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Papazisi Kalliopi Maria

    2017-01-01

    Full Text Available A challenging barrier for the broad, successful implementation of Reversible Solid Oxide Fuel Cell (RSOFC technology for Mars application utilizing CO2 from the Martian atmosphere as primary reactant, remains the long term stability by the effective control and minimization of degradation resulting from carbon built up. The perovskitic type oxide material La0.75Sr0.25Cr0.9Fe0.1O3-δ (LSCF has been developed and studied for its performance and tolerance to carbon deposition, employed as bi-functional fuel electrode in a Reversible SOFC operating on the CO2 cycle (Solid Oxide Electrolysis Cell/SOEC: CO2 electrolysis, Solid Oxide Fuel Cell/SOFC: power generation through the electrochemical reaction of CO and oxygen. A commercial state-of-the-art NiO-YSZ (8% mol Y2O3 stabilized ZrO2 cermet was used as reference material. CO2 electrolysis and fuel cell operation in 70% CO/CO2 were studied in the temperature range of 900-1000°C. YSZ was used as electrolyte while LSM-YSZ/LSM (La0.2Sr0.8MnO3 as oxygen electrode. Results showed that LSCF had high and stable performance under RSOFC operation.

  8. Development of a 1 kW Class SOFC Stack using Doped Lanthanum Gallate

    Energy Technology Data Exchange (ETDEWEB)

    Akikusa, J.; Adachi, K.; Yamada, T.; Akbay, T.; Murakami, N.; Chitose, N.; Hoshino, K.; Hosoi, K.; Yoshida, H.; Sasaki, T.; Inagaki, T.; Ishihara, T.; Takita, Y.

    2002-06-01

    The performance of lanthanum gallate based SOFC has been investigated as a high-energy conversion device. A planar type SOFC which could operate at temperatures below 800 {sup o}C has been jointly developed. As an electrolyte material, lanthanum gallate (LaGaO{sub 3}) with substitutions of Sr for the La site and Mg and Co for the Ga site (LSGMC) was used. The synthesis technique for large-sized cell production has been established, and the performance of a self- supported diameter 154 mm cell with 200 {mu}m electrolyte thickness is investigated. The output power of 50 W has been obtained with a conversion efficiency [LHV] of 45 % for a single cell. In addition, a metallic separator made of stainless steel was chosen and tested successfully for a seal-less stack. The output power of 1 kW by means of the stack of 18 cells has been achieved for the first time utilizing lanthanum gallate. Moreover, NiO-SDC composite powders were prepared by the spray pyrolysis method and used for the anode on 100 {mu}m thickness LSGMC electrolyte with a combination of samarium cobaltite for the cathode. The power density of as high as 1.8 W/cm{sup 2} at 0.7 V terminal voltage was achieved at 800{sup o}C. (author)

  9. AC impedance behavior of a practical-size single-cell SOFC under DC current

    Energy Technology Data Exchange (ETDEWEB)

    Momma, Akihiko; Kaga, Yasuo; Takano, Kiyonami; Nozaki, Ken; Negishi, Akira; Kato, Ken; Kato, Tohru [Fuel Cell Group, Energy Electronics Institute, National Institute of Advanced Industrial Science and Technology, Umezono Tsukuba-shi, Ibaraki 305-8568 (Japan); Inagaki, Toru; Yoshida, Hiroyuki [Energy Use R and D Center, The Kansai Electric Power Company, Inc., 11-20 Nakoji, 3-Chome, Amagasaki, Hyogo 661-0974 (Japan); Hosoi, Kei; Hoshino, Koji; Akbay, Taner; Akikusa, Jun; Yamada, Masaharu; Chitose, Norihisa [Central Research Institute, Naka Research Center, Mitsubishi Materials Corp. 1002-14 Mukohyama, Naka-machi, Naka-gun, Ibaraki 311-0102 (Japan)

    2004-10-29

    AC impedance measurements were carried out using practical-size planar disc-type SOFC which employs lanthanum gallate as a solid electrolyte. The data were obtained under practical conditions of gas flow rate and DC current. Under these conditions, the gas conversion impedance (GCI), which originates from the change of the electromotive force (EMF) caused by the change in anodic gaseous concentrations along the flow direction, was observed in the low-frequency range of the data obtained. The overlapping impedance together with GCI on the low-frequency arc was also estimated. Experimentally obtained GCI was in good agreement with that calculated. It was concluded that GCI was predominant in the impedance data obtained under practical conditions. The shift of the high-frequency intercept in the complex impedance diagrams was shown to appear as a result of the change in the distribution of gaseous composition in the anode. The dependency of the low-frequency arc on temperature was also shown, and it was assumed that the overlapped impedance varies as the temperature changes. The validity of the impedance measurement, as a diagnostic means to evaluate the gas flow in SOFC stack, was suggested.

  10. Thermodynamic simulation of biomass gas steam reforming for a solid oxide fuel cell (SOFC system

    Directory of Open Access Journals (Sweden)

    A. Sordi

    2009-12-01

    Full Text Available This paper presents a methodology to simulate a small-scale fuel cell system for power generation using biomass gas as fuel. The methodology encompasses the thermodynamic and electrochemical aspects of a solid oxide fuel cell (SOFC, as well as solves the problem of chemical equilibrium in complex systems. In this case the complex system is the internal reforming of biomass gas to produce hydrogen. The fuel cell input variables are: operational voltage, cell power output, composition of the biomass gas reforming, thermodynamic efficiency, electrochemical efficiency, practical efficiency, the First and Second law efficiencies for the whole system. The chemical compositions, molar flows and temperatures are presented to each point of the system as well as the exergetic efficiency. For a molar water/carbon ratio of 2, the thermodynamic simulation of the biomass gas reforming indicates the maximum hydrogen production at a temperature of 1070 K, which can vary as a function of the biomass gas composition. The comparison with the efficiency of simple gas turbine cycle and regenerative gas turbine cycle shows the superiority of SOFC for the considered electrical power range.

  11. Comparative LCA of methanol-fuelled SOFCs as auxiliary power systems on-board ships

    International Nuclear Information System (INIS)

    Strazza, C.; Del Borghi, A.; Costamagna, P.; Traverso, A.; Santin, M.

    2010-01-01

    Fuel cells own the potential for significant environmental improvements both in terms of air quality and climate protection. Through the use of renewable primary energies, local pollutant and greenhouse gas emissions can be significantly minimized over the full life cycle of the electricity generation process, so that marine industry accounts renewable energy as its future energy source. The aim of this paper is to evaluate the use of methanol in Solid Oxide Fuel Cells (SOFC), as auxiliary power systems for commercial vessels, through Life Cycle Assessment (LCA). The LCA methodology allows the assessment of the potential environmental impact along the whole life cycle of the process. The unit considered is a 20 kWel fuel cell system. In a first part of the study different fuel options have been compared (methanol, bio-methanol, natural gas, hydrogen from cracking, electrolysis and reforming), then the operation of the cell fed with methanol has been compared with the traditional auxiliary power system, i.e. a diesel engine. The environmental benefits of the use of fuel cells have been assessed considering different impact categories. The results of the analysis show that fuel production phase has a strong influence on the life cycle impacts and highlight that feeding with bio-methanol represents a highly attractive solution from a life cycle point of view. The comparison with the conventional auxiliary power system shows extremely lower impacts for SOFCs.

  12. Evaluation of STS 430 and STS 444 for SOFC Interconnect Applications

    International Nuclear Information System (INIS)

    Kim, S. H.; Huh, J. Y.; Jun, J. H.; Kim, D. H.; Jun, J. H.

    2007-01-01

    Ferritic stainless steels for the SOFC interconnect applications are required to possess not only a good oxidation resistance, but also a high electrical conductivity of te oxide scale that forms during exposure at the SOFC operating environment. In order to understand the effects of alloying elements on the oxidation behavior of ferritic stainless steels and on the electrical properties of oxide scales, two kinds of commercial ferritic stainless steels, STS 430 and STS 444, were investigated by performing isothermal oxidations at 800 .deg. C in a wet air containing 3% H 2 O. The results showed that STS 444 was superior to STS 430 in both of the oxidation resistance and the area specific resistance. Although STS 444 contained a less amount of Mn for the (Mn, Cr) 3 O 4 spinel formation than STS 430, the minor alloying elements of Al and Mo in STS 444, which were accumulated in the base metal region adjacent the scale, were suggested to reduce the scale growth rate and to enhance the scale adherence to the base metal

  13. Analyses of Large Coal-Based SOFCs for High Power Stack Block Development

    Energy Technology Data Exchange (ETDEWEB)

    Recknagle, Kurtis P; Koeppel, Brian J

    2010-10-01

    This report summarizes the numerical modeling and analytical efforts for SOFC stack development performed for the coal-based SOFC program. The stack modeling activities began in 2004, but this report focuses on the most relevant results obtained since August 2008. This includes the latter half of Phase-I and all of Phase-II activities under technical guidance of VPS and FCE. The models developed to predict the thermal-flow-electrochemical behaviors and thermal-mechanical responses of generic planar stacks and towers are described. The effects of cell geometry, fuel gas composition, on-cell reforming, operating conditions, cell performance, seal leak, voltage degradation, boundary conditions, and stack height are studied. The modeling activities to evaluate and achieve technical targets for large stack blocks are described, and results from the latest thermal-fluid-electrochemical and structural models are summarized. Modeling results for stack modifications such as scale-up and component thickness reduction to realize cost reduction are presented. Supporting modeling activities in the areas of cell fabrication and loss of contact are also described.

  14. Palliative effects of H2 on SOFCs operating with carbon containing fuels

    Science.gov (United States)

    Reeping, Kyle W.; Bohn, Jessie M.; Walker, Robert A.

    2017-12-01

    Chlorine can accelerate degradation of solid oxide fuel cell (SOFC) Ni-based anodes operating on carbon containing fuels through several different mechanisms. However, supplementing the fuel with a small percentage of excess molecular hydrogen effectively masks the degradation to the catalytic activity of the Ni and carbon fuel cracking reaction reactions. Experiments described in this work explore the chemistry behind the "palliative" effect of hydrogen on SOFCs operating with chlorine-contaminated, carbon-containing fuels using a suite of independent, complementary techniques. Operando Raman spectroscopy is used to monitor carbon accumulation and, by inference, Ni catalytic activity while electrochemical techniques including electrochemical impedance spectroscopy and voltammetry are used to monitor overall cell performance. Briefly, hydrogen not only completely hides degradation observed with chlorine-contaminated carbon-containing fuels, but also actively removes adsorbed chlorine from the surface of the Ni, allowing for the methane cracking reaction to continue, albeit at a slower rate. When hydrogen is removed from the fuel stream the cell fails immediately due to chlorine occupation of methane/biogas reaction sites.

  15. FEEDSTOCK-FLEXIBLE REFORMER SYSTEM (FFRS) FOR SOLID OXIDE FUEL CELL (SOFC)- QUALITY SYNGAS

    Energy Technology Data Exchange (ETDEWEB)

    Jezierski, Kelly; Tadd, Andrew; Schwank, Johannes; Kibler, Roland; McLean, David; Samineni, Mahesh; Smith, Ryan; Parvathikar, Sameer; Mayne, Joe; Westrich, Tom; Mader, Jerry; Faubert, F. Michael

    2010-07-30

    The U.S. Department of Energy National Energy Technology Laboratory funded this research collaboration effort between NextEnergy and the University of Michigan, who successfully designed, built, and tested a reformer system, which produced highquality syngas for use in SOFC and other applications, and a novel reactor system, which allowed for facile illumination of photocatalysts. Carbon and raw biomass gasification, sulfur tolerance of non-Platinum Group Metals (PGM) based (Ni/CeZrO2) reforming catalysts, photocatalysis reactions based on TiO2, and mild pyrolysis of biomass in ionic liquids (ILs) were investigated at low and medium temperatures (primarily 450 to 850 C) in an attempt to retain some structural value of the starting biomass. Despite a wide range of processes and feedstock composition, a literature survey showed that, gasifier products had narrow variation in composition, a restriction used to develop operating schemes for syngas cleanup. Three distinct reaction conditions were investigated: equilibrium, autothermal reforming of hydrocarbons, and the addition of O2 and steam to match the final (C/H/O) composition. Initial results showed rapid and significant deactivation of Ni/CeZrO2 catalysts upon introduction of thiophene, but both stable and unstable performance in the presence of sulfur were obtained. The key linkage appeared to be the hydrodesulfurization activity of the Ni reforming catalysts. For feed stoichiometries where high H2 production was thermodynamically favored, stable, albeit lower, H2 and CO production were obtained; but lower thermodynamic H2 concentrations resulted in continued catalyst deactivation and eventual poisoning. High H2 levels resulted in thiophene converting to H2S and S surface desorption, leading to stable performance; low H2 levels resulted in unconverted S and loss in H2 and CO production, as well as loss in thiophene conversion. Bimetallic catalysts did not outperform Ni-only catalysts, and small Ni particles were

  16. An Integrated Approach to Modeling and Mitigating SOFC Failure

    Energy Technology Data Exchange (ETDEWEB)

    Jianmin Qu; Andrei Fedorov; Comas Haynes

    2006-05-15

    The specific objectives of this project were: (1) To develop and demonstrate the feasibility of an integrated predictive computer-based tool for fuel cell design and reliability/durability analysis, (2) To generate new scientific and engineering knowledge to better enable SECA Industry Teams to develop reliable, low-cost solid-oxide fuel cell power generation systems, (3) To create technology breakthroughs to address technical risks and barriers that currently limit achievement of the SECA performance and cost goals for solidoxide fuel cell systems, and (4) To transfer new science and technology developed in the project to the SECA Industry Teams. Through this three-year project, the Georgia Tech's team has demonstrated the feasibility of the solution proposed and the merits of the scientific path of inquiry, and has developed the technology to a sufficient level such that it can be utilized by the SECA Industry Teams. This report summarizes the project's results and achievements.

  17. Development of perovskite cathodes for solid oxide fuel cells (SOFC); Desenvolvimento de catodos de perovskitas para celula a combustivel solido de eletrolito solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Perez, J. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica], e-mail: joelma@iq.unesp.br; Pereira, J.T.; Saeki, M.J. [UNESP, Bauru, SP (Brazil). Faculdade de Ciencias

    2006-07-01

    Solid Oxide Fuel Cells (SOFC) are energy conversion systems of great interest for industrial applications because they present a high efficiency for energy generation and several advantages for the environment. In this work, perovskite type oxides La{sub 085}Sr{sub 0,15}MnO{sub 3}, La{sub 0,7} Sr{sub 0,3}MnO{sub 3}, La{sub 0,6}Sr{sub 0,4}MnO{sub 3}, La{sub 0,85}Sr{sub 0,15}CoO{sub 3}, La{sub 0,7}Sr{sub 0,3}CoO{sub 3}, La{sub 0,6}Sr{sub 0,4}CoO{sub 3}, La{sub 0.6}Sr{sub 0,4}Fe{sub 0,8}Co{sub 0,2}O{sub 3} e La{sub 0.6}Sr{sub 0,4}Fe{sub 0,4}Co{sub 0,6}O{sub 3} were prepared by a polymeric method with the purpose of using them as cathodes in SOFCs. The electrochemical cell was mounted utilizing YSZ (ZrO{sub 2} - 8 mol%Y{sub 2}O{sub 3}) disks as electrolyte, where a paste containing Pt was calcined onto one face while the other one was covered with the oxide materials synthesized ('screen printing'). The oxide materials prepared were characterized by X-ray diffraction, transmission electronic microscopy and thermogravimetry. The oxygen reduction reaction was studied by taking polarization curves in oxygen and/or air (800 deg C a 950 deg C). The best performance was obtained for 15 {mu}m thickness electrodes La{sub 0.6}Sr{sub 0,4}MnO{sub 3} and La{sub 0.6}Sr{sub 0,4}MnO{sub 3} with addition of dispersed Pt. (author)

  18. Clearing up the kinetics in high temperature fuel cells SOFC. Final report; Aufklaerung der Kinetik in Hochtemperatur-Brennstoffzellen SOFC. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Stimming, U

    1997-05-12

    In this work, the kinetics of the oxygen reduction of the SOFC cathode are to be detailed, i.e., depending on the parameters of electrode potential, temperature and oxygen partial pressure, they are to be examined with impedance spectroscopy and quasi-stationary current/voltage measurements. From the dependence of the impedances and the current density on the temperature and the oxygen partial pressure, apparent activation energies and pre-exponential factors as well as apparent reaction orders are to be determined, in order to obtain information on possible reaction mechanisms. These investigations should be carried out not only on standard cathode material (La{sub 1-x}Sr{sub x}MnO{sub 3}, LSM) but also on modified LSM cathodes. This modification should consist either of the addition of noble metal catalysts or in a change of the composition of the cathode material, and should lead to increased catalytic activity of the cathode. In addition, using the example of the standard cathode, different possible reaction mechanisms should be compared by a computer simulation of the current/voltage measurements and impedance spectra. (orig.) [Deutsch] In dieser Arbeit soll die Kinetik der Sauerstoffreduktion an der SOFC Kathode detailliert, d.h. in Abhaengigkeit der Parameter Elektrodenpotential, Temperatur und Sauerstoffpartialdruck mit Impedanzspektroskopie und quasi-stationaeren Strom/Spannungsmessungen untersucht werden. Aus den Abhaengigkeiten der Impedanzen und der Stromdichte von der Temperatur und vom Sauerstoffpartialdruck sollen scheinbare Aktivierungsenergien und prae-exponentielle Faktoren sowie scheinbare Reaktionsordnungen bestimmt werden, um Hinweise auf moegliche Reaktionsmechanismen zu erhalten. Diese Untersuchungen sollen nicht nur am Standardkathodenmaterial (La{sub 1-x}Sr{sub x}MnO{sub 3}, LSM), sondern auch an modifizierten LSM-Kathoden durchgefuehrt werden. Diese Modifizierung soll entweder im Zusatz von Edelmetallkatalysatoren oder in einer Aenderung

  19. Recent Progress in Development and Manufacturing of SOFC at Topsoe Fuel Cell A/S and Risø DTU

    DEFF Research Database (Denmark)

    Christiansen, Niels; Holm-Larsen, Helge; Primdahl, Søren

    2011-01-01

    effort is directed towards improvement of current generations as well as development of the next generation SOFC technology. The innovative concept of the next generation, aiming at improved reliability and robustness, is based on metal-supported cells and nano-structured electrodes with perspectives...

  20. A chemically stable electrolyte with a novel sandwiched structure for proton-conducting solid oxide fuel cells (SOFCs)

    KAUST Repository

    Bi, Lei; Traversa, Enrico

    2013-01-01

    A chemically stable electrolyte structure was developed for proton-conducting SOFCs by using two layers of stable BaZr0.7Pr 0.1Y0.2O3 -δ to sandwich a highly-conductive but unstable BaCe0.8Y0.2O 3 -δ electrolyte layer. The sandwiched electrolyte

  1. Evidence of the Current Collector Effect: Study of the SOFC Cathode Material Ca3Co4O9+d

    NARCIS (Netherlands)

    Rolle, A.; Thoréton, V.; Rozier, P.; Capoen, E.; Mentré, O.; Boukamp, Bernard A.; Daviero-Minaud, S.

    2012-01-01

    In the study of the performance of solid oxide fuel cell (SOFC) electrodes, the possible influence of the applied current collector is often not mentioned or recognized. In this article, as part of an optimization study of the potentially attractive Ca3Co4O9+δ cathode material (Ca349), special

  2. Predicting the ultimate potential of natural gas SOFC power cycles with CO2 capture - Part B: Applications

    Science.gov (United States)

    Campanari, Stefano; Mastropasqua, Luca; Gazzani, Matteo; Chiesa, Paolo; Romano, Matteo C.

    2016-09-01

    An important advantage of solid oxide fuel cells (SOFC) as future systems for large scale power generation is the possibility of being efficiently integrated with processes for CO2 capture. Focusing on natural gas power generation, Part A of this work assessed the performances of advanced pressurised and atmospheric plant configurations (SOFC + GT and SOFC + ST, with fuel cell integration within a gas turbine or a steam turbine cycle) without CO2 separation. This Part B paper investigates such kind of power cycles when applied to CO2 capture, proposing two ultra-high efficiency plant configurations based on advanced intermediate-temperature SOFCs with internal reforming and low temperature CO2 separation process. The power plants are simulated at the 100 MW scale with a set of realistic assumptions about FC performances, main components and auxiliaries, and show the capability of exceeding 70% LHV efficiency with high CO2 capture (above 80%) and a low specific primary energy consumption for the CO2 avoided (1.1-2.4 MJ kg-1). Detailed results are presented in terms of energy and material balances, and a sensitivity analysis of plant performance is developed vs. FC voltage and fuel utilisation to investigate possible long-term improvements. Options for further improvement of the CO2 capture efficiency are also addressed.

  3. High temperature electrolyte supported Ni-GDC/YSZ/LSM SOFC operation on two-stage Viking gasifier product gas

    DEFF Research Database (Denmark)

    Hofmann, P.; Schweiger, A.; Fryda, L.

    2007-01-01

    and tar traces. The chosen SOFC was electrolyte supported with a nickel/gadolinium-doped cerium oxide (Ni-GDC) anode, known for its carbon deposition resistance. Through humidification the steam to carbon ratio (S/C) was adjusted to 0.5, which results in a thermodynamically carbon free condition...

  4. Towards retrofitting integrated gasification combined cycle (IGCC) power plants with solid oxide fuel cells (SOFC) and CO

    NARCIS (Netherlands)

    Thallam Thattai, A.; Oldenbroek, V.D.W.M.; Schoenmakers, L; Woudstra, T.; Purushothaman Vellayani, A.

    2017-01-01

    This article presents a detailed thermodynamic case study based on the Willem-Alexander Centrale (WAC) power plant in the Netherlands towards retrofitting SOFCs in existing IGCC power plants with a focus on near future implementation. Two systems with high percentage (up to 70%) biomass

  5. Predicting the ultimate potential of natural gas SOFC power cycles with CO2 capture : Part B: Applications

    NARCIS (Netherlands)

    Campanari, Stefano; Mastropasqua, Luca; Gazzani, Matteo; Chiesa, Paolo; Romano, Matteo C.

    2016-01-01

    An important advantage of solid oxide fuel cells (SOFC) as future systems for large scale power generation is the possibility of being efficiently integrated with processes for CO2 capture. Focusing on natural gas power generation, Part A of this work assessed the performances of advanced

  6. Continued SOFC cell and stack technology and improved production methods

    Energy Technology Data Exchange (ETDEWEB)

    Wandel, M.; Brodersen, K.; Phair, J. (and others)

    2009-05-15

    Within this project significant results are obtained on a number of very diverse areas ranging from development of cell production, metallic creep in interconnect to assembling and test of stacks with foot print larger than 500 cm2. Out of 38 milestones 28 have been fulfilled and 10 have been partly fulfilled. This project has focused on three main areas: 1) The continued cell development and optimization of manufacturing processes aiming at production of large foot-print cells, improving cell performance and development environmentally more benign production methods. 2) Stack technology - especially stacks with large foot print and improving the stack design with respect to flow geometry and gas leakages. 3) Development of stack components with emphasis on sealing (for 2G as well as 3G), interconnect (coat, architecture and creep) and test development. Production of cells with a foot print larger than 500 cm2 is very difficult due to the brittleness of the cells and great effort has been put into this topic. Eight cells were successfully produced making it possible to assemble and test a real stack thereby giving valuable results on the prospects of stacks with large foot print. However, the yield rate is very low and a significant development to increase this yield lies ahead. Several lessons were learned on the stack level regarding 'large foot print' stacks. Modelling studies showed that the width of the cell primarily is limited by production and handling of the cell whereas the length (in the flow direction) is limited by e.g. pressure drop and necessary manifolding. The optimal cell size in the flow direction was calculated to be between approx20 cm and < 30 cm. From an economical point of view the production yield is crucial and stacks with large foot print cell area are only feasible if the cell production yield is significantly enhanced. Co-casting has been pursued as a production technique due to the possibilities in large scale production

  7. SOFC direct fuelling with high-methane gases: Optimal strategies for fuel dilution and upgrade to avoid quick degradation

    International Nuclear Information System (INIS)

    Baldinelli, A.; Barelli, L.; Bidini, G.; Di Michele, A.; Vivani, R.

    2016-01-01

    Highlights: • SOFCs are operated on natural gas and biogas direct feeding. • Methane partial oxidation and dry reforming are compared. • The optimal oxygen-to-carbon stoichiometry to avoid degradation is determined for both natural gas and biogas. • NiYSZ anodes degradation mechanisms are investigated though SEM-EDX and XRD. - Abstract: In the outlook of the transition to the carbon-free society, low-carbon gases, such as natural gas or biogas, are very promising. The first is commonly used for stationary applications based on Solid Oxide Fuel Cells (SOFCs) equipped with external reformers. Similar installations are required when the SOFC is run on biogas. Yet, high SOFC operative temperature enables internal decomposition of light hydrocarbons, therefore allowing the suppression of external reforming. Evidently, this brings about benefits in terms of system complexity and cost reduction. Nonetheless, unlike reformate fuels, direct exposure to large amount of methane favours SOFC anodes degradation. Implementing a systematic experimental approach, this paper aims at determining a simple operative strategy to carry out direct feeding without meeting with quick degradation issues, producing interesting outcomes with regards to the management of SOFC-based systems. Particularly, the regulation of the oxygen-to-carbon (O/C) relative fraction of the fuel through air addition to natural gas and partial CO_2 separation from biogas is helpful in the prevention of those mechanisms. In this study, NiYSZ anode SOFCs are exposed to air-diluted natural gas and upgraded biogas, featuring O/C between 0.2 and 1.2. Tracing these cases, at 800 °C and 500 mA/cm"2 constant load, cell performances are measured over a time interval of 100 h. Finally, post-mortem analysis is performed on the specimens to investigate material morphological changes after the exposure to high-methane fuels. Results showed that O/C = 0.8 (+63% air) is the best case to employ air-diluted natural gas

  8. Maturing of SOFC cell and stack production technology and preparation for demonstration of SOFC stacks. Part 2

    Energy Technology Data Exchange (ETDEWEB)

    2006-07-01

    The TOFC/Riso pilot plant production facility for the manufacture of anode-supported cells has been further up-scaled with an automated continuous spraying process and an extra sintering capacity resulting in production capacity exceeding 15,000 standard cells (12x12 cm2) in 2006 with a success rate of about 85% in the cell production. All processing steps such as tape-casting, spraying, screen-printing and atmospheric air sintering in the cell production have been selected on condition that up-scaling and cost effective, flexible, industrial mass production are feasible. The standard cell size is currently being increased to 18x18 cm2, and 150 cells of this size have been produced in 2006 for our further stack development. To improve quality and lower production cost, a new screen printing line is under establishment. TOFC's stack design is an ultra compact multilayer assembly of cells (including contact layers), metallic interconnects, spacer frames and glass seals. The compactness ensures minimized material consumption and low cost. Standard stacks with cross flow configuration contains 75 cells (12x12cm2) delivering about 1.2 kW at optimal operation conditions with pre-reformed NG as fuel. Stable performance has been demonstrated for 500-1000 hours. Significantly improved materials, especially concerning the metallic interconnect and the coatings have been introduced during the last year. Small stacks (5-10 cells) exhibit no detectable stack degradation using our latest cells and stack materials during test periods of 500-1000 hours. Larger stacks (50-75 cells) suffer from mal-distribution of gas and air inside the stacks, gas leakage, gas cross-over, pressure drop, and a certain loss of internal electrical contact during operation cycles. Measures have been taken to find solutions during the following development work. The stack production facilities have been improved and up-scaled. In 2006, 5 standard stacks have been assembled and burned in based on

  9. Manganates of lanthanum and strontium as cathode of fuel cells (SOFC); Manganatos de lantanio e estroncio como catodo de celulas combustiveis (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Marfran C. de; Nascimento, Rubens M. do; Martinelli, Antonio E.; Melo, Dulce M.A. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2004-07-01

    The fuel cells if constitute currently as a promising alternative modular generation of electric energy to leave of chemical energy. The SOFCs is distinguished as promising for the industry of the oil, therefore they can use the produced natural gas in the platforms as combustible, allowing generation of raised power electric.The material of cathode constituent of the cell are oxides with perovskites structure, normally doped with a earthy-alkaline element (Sr{sup +3}). In this work, two compositions of the La{sub 1-x}Sr{sub x} MnO{sub 3} system were synthesized (x = 0,15 and 0,30), through the Pechini method and after resultants of the process they were characterized by X- Ray diffraction, Fourier-transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TG/DTG) and laser grain size analysis. The systems in study shown similar behavior how much to the results of absorption in the region of infra-red ray and TG/DTG, therefore if it can prove the loss of organic substance with the increase of the temperature.The average particle diameter for the two systems also increased gradually with the temperature. In general way the synthesis method was satisfactory for the formation of the perovskites phase in the two studied compositions. (author)

  10. Direct internal steam reforming of ethanol in a solid oxide fuel cell (SOFC) - A thermodynamic analysis

    International Nuclear Information System (INIS)

    Lima da Silva, Aline; De Fraga Malfatti, Celia; Heck, Nestor Cesar; Melo Halmenschlager, Cibele

    2003-01-01

    Among the various types of fuel cells, the solid oxide fuel cell (SOFC) has attracted considerable interest due to the possibility for operation with an internal reformer and higher system efficiency. In SOFC, high operative temperature allows the direct conversion of ethanol into H 2 and CO to take place in the electrochemical cell. Ethanol is considered to be an attractive fuel because it is a renewable energy source and presents some advantages over other green fuels such as safety in storage and handling. Direct internal reforming of ethanol, however, can produce undesirable products that diminish system efficiency and, in the case of carbon deposition over the anode, promote the growth of carbon filaments attached to the anode crystallites which generate massive forces within the electrode structure leading to its rapid breakdown. In this context, a thermodynamic analysis is fundamental to predict the product distribution as well as the conditions favorable for carbon to precipitate inside the cell. Despite of such importance, there are few works in literature dealing with thermodynamic analysis of the direct internal steam reforming of ethanol in fuel cell systems. Hence, the aim of this work is to find appropriate ranges for operating conditions where carbon deposition in SOFC with direct internal reforming operation is not feasible, in temperature range of 500- 1200K. The calculation here is more complicated than that for a reformer because the disappearance of hydrogen and the generation of H 2 O from electrochemical reaction must be taken into account. In the present study, the effects of hydrogen consumption on anode components and on carbon formation are investigated. Equilibrium determinations are performed by the Gibbs energy minimization method, considering the following species: H 2 , H 2 O, CH 4 , CO, CO 2 and C gr . (graphite). The effect of the type of solid electrolyte (oxygen-conducting and hydrogen-conducting) on carbon formation is also

  11. Sense of community and its relationship with walking and neighborhood design.

    Science.gov (United States)

    Wood, Lisa; Frank, Lawrence D; Giles-Corti, Billie

    2010-05-01

    The aim of this study is to examine the association between sense of community, walking, and neighborhood design characteristics. The current study is based on a sub-sample of participants (n=609) from the US Atlanta SMARTRAQ study who completed a telephone survey capturing physical activity patterns, neighborhood perceptions, and social interactions. Objective measures of neighborhood form were also computed. Univariate and multivariate models (General Linear Models (GLM)) were used to examine the association between sense of community (SofC) and aspects of the built environment, physical activity, and neighborhood perceptions. In multivariate models the impact on SofC was examined with progressive adjustment for demographics characteristics followed by walking behavior, neighborhood design features, neighborhood perceptions and time spent traveling in a car. After adjustment, SofC was positively associated with leisurely walking (days/week), home ownership, seeing neighbors when walking and the presence of interesting sites. SofC was also associated with higher commercial floor space to land area ratios (FAR) - a proxy for walkable site design that captures the degree to which retail destinations are set back from the street, the amount of surface parking, and urban design of an area. Conversely the presence of more mixed use and perceptions of steep hills were inversely associated with SofC. SofC is enhanced by living in areas that encourage leisurely walking, hence it is associated with living in neighbourhoods with lower levels of land use mix, but higher levels of commercial FAR. Our results suggest that in terms of SofC, the presence of commercial destinations may inhibit social interaction among local residents unless urban design is used to create convivial pedestrian-friendly commercial areas, e.g., providing street frontage, rather than flat surface parking. This finding has policy implications and warrants further investigation. Copyright 2010 Elsevier

  12. A Brief Description of High Temperature Solid Oxide Fuel Cell’s Operation, Materials, Design, Fabrication Technologies and Performance

    Directory of Open Access Journals (Sweden)

    Muneeb Irshad

    2016-03-01

    Full Text Available Today’s world needs highly efficient systems that can fulfill the growing demand for energy. One of the promising solutions is the fuel cell. Solid oxide fuel cell (SOFC is considered by many developed countries as an alternative solution of energy in near future. A lot of efforts have been made during last decade to make it commercial by reducing its cost and increasing its durability. Different materials, designs and fabrication technologies have been developed and tested to make it more cost effective and stable. This article is focused on the advancements made in the field of high temperature SOFC. High temperature SOFC does not need any precious catalyst for its operation, unlike in other types of fuel cell. Different conventional and innovative materials have been discussed along with properties and effects on the performance of SOFC’s components (electrolyte anode, cathode, interconnect and sealing materials. Advancements made in the field of cell and stack design are also explored along with hurdles coming in their fabrication and performance. This article also gives an overview of methods required for the fabrication of different components of SOFC. The flexibility of SOFC in terms fuel has also been discussed. Performance of the SOFC with varying combination of electrolyte, anode, cathode and fuel is also described in this article.

  13. Feasibility study of solid oxide fuel cell engines integrated with sprinter gas turbines: Modeling, design and control

    Science.gov (United States)

    Jia, Zhenzhong; Sun, Jing; Dobbs, Herb; King, Joel

    2015-02-01

    Conventional recuperating solid oxide fuel cell (SOFC)/gas turbine (GT) system suffers from its poor dynamic capability and load following performance. To meet the fast, safe and efficient load following requirements for mobile applications, a sprinter SOFC/GT system concept is proposed in this paper. In the proposed system, an SOFC stack operating at fairly constant temperature provides the baseline power with high efficiency while the fast dynamic capability of the GT-generator is fully explored for fast dynamic load following. System design and control studies have been conducted by using an SOFC/GT system model consisting of experimentally-verified component models. In particular, through analysis of the steady-state simulation results, an SOFC operation strategy is proposed to maintain fairly constant SOFC power (less than 2% power variation) and temperature (less than 2 K temperature variation) over the entire load range. A system design procedure well-suited to the proposed system has also been developed to help determining component sizes and the reference steady-state operation line. In addition, control analysis has been studied for both steady-state and transient operations. Simulation results suggest that the proposed system holds the promise to achieve fast and safe transient operations by taking full advantage of the fast dynamics of the GT-generator.

  14. Microstructure degradation of LSM-YSZ cathode in SOFCs operated at various conditions

    DEFF Research Database (Denmark)

    Liu, Yi-Lin; Thydén, Karl Tor Sune; Chen, Ming

    2012-01-01

    Systematic microstructural analyses have been carried out on a series of technological SOFCs that went through long-term cell tests with various operating parameters including temperature, current load and time length under current. For the LSM-YSZ cathode, a number of microstructure degradation...... mechanisms have been identified. And it has been observed that different mechanisms dominate the degradation process under different test conditions. The severe cathode degradation at 750 °C operation with high current density is attributed to a loss of the cathode/electrolyte interface stability....... For the cells tested at 850 °C, the interface stability is maintained due to further sintering during cell operation. A cell test lasting for 2 years (17500 h) at 850 °C with a moderate current density (not greater than 1 A/cm2) has shown that the cathode microstructure is fairly robust to the degradation...

  15. Microstructural studies on degradation of interface between LSM–YSZ cathode and YSZ electrolyte in SOFCs

    DEFF Research Database (Denmark)

    Liu, Yi-Lin; Hagen, Anke; Barfod, Rasmus

    2009-01-01

    The changes in the cathode/electrolyte interface microstructure have been studied on anode-supported technological solid oxide fuel cells (SOFCs) that were subjected to long-term (1500 h) testing at 750 °C under high electrical loading (a current density of 0.75 A/cm2). These cells exhibit...... different cathode degradation rates depending on, among others, the composition of the cathode gas, being significantly smaller in oxygen than in air. FE-SEM and high resolution analytical TEM were applied for characterization of the interface on a submicron- and nano-scale. The interface degradation has...... to decrease further due to the more pronounced formation of insulating zirconate phases that are present locally and preferably in LSM/YSZ electrolyte contact areas. The effects of the cathode gas on the interface degradation are discussed considering the change of oxygen activity at the interface, possible...

  16. In situ observations of microstructural changes in SOFC anodes during redox cycling

    DEFF Research Database (Denmark)

    Klemensø, Trine; Appel, C. C.; Mogensen, Mogens Bjerg

    2006-01-01

    The anode-supported solid oxide fuel cell (SOFC) degrades when the anode is subjected to redox cycling. The degradation has qualitatively been related to microstructural changes in the nickel-yttria stabilized zirconia anode of the tested cells. In this work, the microstructural changes were...... observed in situ using environmental scanning electron microscopy. In the reduced state, a dynamic rounding of the nickel particles occurred. The oxide growth upon re-oxidation depended on the oxidation kinetics. During rapid oxidation, the NiO particles divided into 2-4 particles, which grew...... into the surrounding voids. For slower oxidation, an external oxide layer was seen to develop around the individual particles. (c) 2006 The Electrochemical Society....

  17. Application of Coordinated SOFC and SMES Robust Control for Stabilizing Tie-Line Power

    Energy Technology Data Exchange (ETDEWEB)

    Ning Zhang; Wei Gu; Haojun Yu; Wei Liu [School of Electrical Engineering, Southeast University, Nanjing (China)

    2013-04-15

    Wind power causes fluctuations in power systems and introduces issues concerning system stability and power quality because of the lack of controllability of its discontinuous and intermittent resources. This paper presents a coordinated control strategy for solid oxide fuel cells (SOFCs) and superconducting magnetic energy storage (SMES) to match the intermittent wind power generation and compensate for the rapid load changes. An optimal H{sub {infinity}}control method, where the weighting function selection is expressed as an optimization problem, is proposed to mitigate tie-line power fluctuations and the mixed-sensitivity approach is used to deal with the interference suppression. Simulation results show that the proposed method significantly improves the smoothing effect of wind power fluctuations. Compared with the conventional control method, the proposed method has better anti-interference performance in various operating situations.

  18. Electrochemical Characterization and Degradation Analysis of Large SOFC Stacks by Impedance Spectroscopy

    DEFF Research Database (Denmark)

    Mosbæk, Rasmus Rode; Hjelm, Johan; Barfod, R.

    2013-01-01

    As solid oxide fuel cell (SOFC) technology is moving closer to a commercial break through, lifetime limiting factors, and methods to measure the “state-of-health” of operating cells and stacks are becoming of increasing interest. This requires application of advanced methods for detailed...... electrochemical characterization during operation. An experimental stack with low ohmic resistance from Topsoe Fuel Cell A/S was characterized in detail using electrochemical impedance spectroscopy (EIS). An investigation of the optimal geometrical placement of the current feeds and voltage probes was carried out...... with hydrogen as fuel with 52% fuel utilization and constant current load (0.2 A cm–2) at 750 °C. Stack interconnects were coated with six different coatings to prevent chromium poisoning on the cathode side. Four repeating units (RUs) with different coatings were selected for detailed impedance analysis. EIS...

  19. Effect of Humidity in Air on Performance and Long-Term Durability of SOFCs

    DEFF Research Database (Denmark)

    Hagen, Anke; Neufeld, Kai; Liu, Yi-Lin

    2010-01-01

    Anode-supported solid oxide fuel cells (SOFCs) based on Ni–yttria-stabilized zirconia (YSZ) anodes, YSZ electrolytes, and lanthanum strontium manganite (LSM)–YSZ cathodes were studied with respect to durability in humid air (~4%) typically over 1500 h. Operating temperature and current density were...... varied between 750 and 850°C and 0.25–0.75 A/cm2, respectively. The introduction of humidity affected the cell voltage under polarization of the cell, and this effect was (at least partly) reversible upon switching off the humidity. Generally, the studied cells were operated in humid air under...... technologically relevant conditions over more than 1500 h. Improvements at the cathode/electrolyte interface made it possible to obtain highly stable cells, which can be operated under high current density and at 750°C in humid air, conditions that cause significant cell voltage degradation in dry air on cells...

  20. Effect of Humidity in Air on Performance and Long-Term Durability of SOFCs

    DEFF Research Database (Denmark)

    Hagen, Anke; Chen, Ming; Neufeld, Kai

    2009-01-01

    Anode supported SOFCs based on Ni-YSZ anodes, YSZ electrolytes, and LSM-YSZ cathodes were studied with respect to durability in humid air (~4%) over typically 1500 hours. Operating temperature and current density were varied between 750 and 850 oC and 0.25-0.75 A/cm2, respectively. It was found...... that the introduction of humidity affected the cell voltage under polarization of the cell and that this effect was (at least partly) reversible upon switching off the humidity, probably related to a segregation of impurities towards the three phase boundary in the presence of humidity. Generally, the studied cells...... were successfully operated in humid air under technologically relevant conditions. Improvements at the cathode/electrolyte interface made it possible to obtain highly stable cells, which can be operated under high current density and at 750 oC in humid air - conditions that are known to cause...

  1. Properties and Performance of SOFCs Produced on a Pre-Pilot Plant Scale

    DEFF Research Database (Denmark)

    Hagen, Anke; Menon, Mohan; Barfod, Rasmus

    2006-01-01

    specific cell resistance at 850 °C was found to be 0.24 Ω cm2 with a standard deviation of 0.05 Ω cm2. The variation in performance between the cells can be largely attributed to variations in the cathode performance. Experimental evidence will be presented on full 4 × 4 cm2 cells, symmetric cells with two......In the present paper, anode supported solid oxide fuel cells (SOFCs), produced on a pre-pilot plant scale in ten batches of ∼100 cells, are characterised with respect to performance. The main purpose was to evaluate the reproducibility of the scaled-up process. Based on 20 tests, the average area...

  2. Mechanical Behaviour of Glassy Composite Seals for IT-SOFC Application

    DEFF Research Database (Denmark)

    Nielsen, Karsten Agersted; Solvang, Mette; Nielsen, Sofie Birkedal Lund

    2007-01-01

    Glass-based sealants have been developed with emphasis on filler material and surface treatment of the sealing components in order to optimise their mechanical and functional behaviour during the initial sealing process as well as during thermal cycling of the SOFC-stack after exposure to operating...... conditions. The bonding strength and microstructure of the interfaces between composite seals and interconnect materials were investigated as a function of surface treatment of the sealing surfaces, glass matrix composition, sealing pressure and temperature. The initial sealing performance and resistance...... to thermal cycling were then investigated on selected combinations of materials after ageing. Strongest bonding between sodium aluminosilicate glass composite and steel surfaces was obtained for sealing at 850°C. For the strongest interface, having shear strength of 2.35 MPa, rupture occurred in the glass...

  3. Impedance of porous IT-SOFC LSCF:CGO composite cathodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Jacobsen, Torben; Wandel, Marie

    2011-01-01

    The impedance of technological relevant LSCF:CGO composite IT-SOFC cathodes was studied over a very wide performance range. This was experimentally achieved by impedance measurements on symmetrical cells with three different microstructures in the temperature range 550–850 °C. In order to account...... for the impedance spectra of the poor performing cathodes the Finite-Length-Gerischer (FLG) impedance was derived and applied to the impedance data. The FLG impedance describes for a given microstructure the situation where the cathode is made too thin from a cathode development point of view. The moderate...... performing cathodes showed a slightly suppressed Gerischer impedance, while the impedance spectra of the well performing cathodes showed the presence of an arc due to oxygen gas diffusion. The overall impedance of the well performing cathodes could be described with a slightly suppressed Gerischer impedance...

  4. Application of Coordinated SOFC and SMES Robust Control for Stabilizing Tie-Line Power

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2013-04-01

    Full Text Available Wind power causes fluctuations in power systems and introduces issues concerning system stability and power quality because of the lack of controllability of its discontinuous and intermittent resources. This paper presents a coordinated control strategy for solid oxide fuel cells (SOFCs and superconducting magnetic energy storage (SMES to match the intermittent wind power generation and compensate for the rapid load changes. An optimal H∞ control method, where the weighting function selection is expressed as an optimization problem, is proposed to mitigate tie-line power fluctuations and the mixed-sensitivity approach is used to deal with the interference suppression. Simulation results show that the proposed method significantly improves the smoothing effect of wind power fluctuations. Compared with the conventional control method, the proposed method has better anti-interference performance in various operating situations.

  5. Barium boron silicate glass-ceramic for use as sealant in planar SOFC

    International Nuclear Information System (INIS)

    Silva, M.J.; Castanho, S.R.H. Mello; Reis, S.T.

    2012-01-01

    Glass-ceramic seals play an important role in the performance of the solid oxide fuel cell (SOFC). In this work glass-ceramic seals are discussed from the point of view of the thermal behavior of the glass and the electrochemical parameters obtained from polarization curves such as corrosion current densities (i corr ), and corrosion potential (E corr ). A seal material must have a combination of thermal-mechanical and electrochemical properties in order to seal cell components and stacks and prevent side reactions. It must be stable in oxidizing and reducing atmospheres and withstand thermal cycles between room temperature and the cell operating temperature (800 to 900°C). Glass-ceramics in the system BaO- B 2 O 3 -Al 2 O 3 -SiO 2 were investigated and compared from the point of view of sealing ability. Dilatometric analysis, thermal stability against crystallization, microstructure and electrochemical durability are discussed. (author)

  6. Investigation of nanoporous platinum thin films fabricated by reactive sputtering: Application as micro-SOFC electrode

    Science.gov (United States)

    Jung, WooChul; Kim, Jae Jin; Tuller, Harry L.

    2015-02-01

    Highly porous Pt thin films, with nano-scale porosity, were fabricated by reactive sputtering. The strategy involved deposition of thin film PtOx at room temperature, followed by the subsequent decomposition of the oxide by rapid heat treatment. The resulting films exhibited percolating Pt networks infiltrated with interconnected nanosized pores, critical for superior solid oxide fuel cell cathode performance. This approach is particularly attractive for micro-fabricated solid oxide fuel cells, since it enables fabrication of the entire cell stack (anode/electrolyte/cathode) within the sputtering chamber, without breaking vacuum. In this work, the morphological, crystallographic and chemical properties of the porous electrode were systematically varied by control of deposition conditions. Oxygen reduction reaction kinetics were investigated by means of electrochemical impedance spectroscopy, demonstrating the critical role of nano-pores in achieving satisfactory micro-SOFC cathode performance.

  7. Fabricating Pinhole-Free YSZ Sub-Microthin Films by Magnetron Sputtering for Micro-SOFCs

    Directory of Open Access Journals (Sweden)

    T. Hill

    2011-01-01

    Full Text Available Submicron thin yttria stabilized zirconia (YSZ films were prepared on a variety of substrates with different surface morphologies by magnetron sputtering followed by thermal oxidation. Pinholes were observed in the films deposited on nanoporous alumina substrates. Initial dense Y/Zr films developed nanocracks after thermal oxidation on smooth Si wafer substrates. At optimal sputtering and oxidation conditions, smooth and crack/pore-free films were achieved on Si wafer substrates. The thin YSZ films exhibited fully ionic conduction with ionic conductivities, and activation energy corroborated well with the values from commercial YSZ plates. The thin YSZ films can be utilized in Solid Oxide Fuel Cells (SOFCs for intermediate temperature operations.

  8. Determination of global and local residual stresses in SOFC by X-ray diffraction

    International Nuclear Information System (INIS)

    Villanova, Julie; Sicardy, Olivier; Fortunier, Roland; Micha, Jean-Sebastien; Bleuet, Pierre

    2010-01-01

    Solid Oxide Fuel Cell (SOFC) is a high-performance electrochemical device for energy conversion. A single cell is composed of five layers made of different ceramic materials: anode support, anode functional layer, electrolyte, cathode functional layer and cathode. The mechanical integrity of the cell is a major issue during its lifetime, especially for the electrolyte layer. Damage of the cells is mainly due to the high operating temperature, the 'redox' behaviour of the anode and the brittleness of the involved materials. Since residual stresses are known to play a significant role in the damage evolution, it is important to determine them. For this purpose, residual stresses in an anode-supported planar SOFC were measured by X-ray diffraction. Firstly, macroscopic stresses in each phase of each layer were studied using the sin 2 ψ method on a laboratory X-ray goniometer at room temperature. This technique enables the calculation of residual stress of the material from the measurement of the crystal lattice deformation. The electrolyte has been found under bi-axial compressive stress of -920 MPa. Secondly, X-ray measurements controlling depth penetration were made in the electrolyte using grazing incidence method. The results show that the stress is not homogenous in the layer. The first five micrometers of the electrolyte have been found less constrained (-750 MPa) than the complete layer, suggesting a gradient of deformation in the electrolyte from the interface with the Anode Functional Layer to the free surface. Finally, local stress measurements were made on the electrolyte layer by X-ray synchrotron radiation that allows high accuracy measurement on the (sub-) micrometer scale. Polychromatic and monochromatic beams are used to determine the complete strain tensor from grain to grain in the electrolyte. First results confirm the macroscopic stress trend of the electrolyte. These X-ray techniques at different scales will contribute to a better understanding

  9. Aspects of industrial production of solid electrolyte fuel cells (SOFC) by thermal spraying technology; Aspekte industrieller Fertigung von Festelektrolyt-Brennstoffzellen (SOFC) mittels thermischer Beschichtungsverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Weckmann, Hannes

    2010-07-01

    The present thesis deals with measures to optimize the large-volume production of Solid Oxide Fuel Cells (SOFC) based on thermal spraying technology. Based on the well-established Vacuum Plasma Spraying (VPS) at DLR the potential of alternative thermal spraying techniques as well as alternative base materials was investigated in order to deposit SOFC-anode, electrolyte and insulating layers. Production costs, reproducibility and long-term stability of the production process as well as the fuel cell performance were major target criteria. Depending on the parameter set applied when using the cost efficient Atmospheric Plasma Spraying (APS) in combination with Nickel-Graphite as base material a significant improvement of gas permeability and electrical conductivity was achieved in comparison to the VPS sprayed reference anode. The power density of a fuel cell with an APS-Nickel-Graphite anode (184 mW/cm{sup 2}) was slightly better than the performance with a VPS reference anode (159 mW/cm{sup 2}). In comparison to the VPS process, ceramic electrolyte layers of fully stabilized Zirconia (YSZ) with significantly higher gas tightness could be demonstrated when high energy processes such as Low Pressure Plasma Spraying (LPPS). Thin-film Low Pressure Plasma Spraying (LPPS-Thin-film) and High Velocity Oxy Fuel Spraying (HVOF) were applied. The power density of a fuel cell equipped with an HVOF electrolyte was significantly improved to 234 mW/cm{sup 2} as compared to 187 mW/cm{sup 2} with the VPS sprayed reference cell. Further improvement of the power density was achieved with an LPPS-electrolyte (273 mW/cm{sup 2}). HVOF and VPS sprayed layers of pure Spinel in composite with metallic active braze (equivalent to the sealing between individual layers in the fuel cell stack) could exceed the demanded charge transfer resistance of >1 k{omega}cm{sup 2} at 800 C operating temperature only in few cases. When blended base powder of Spinel and Magnesia in combination with the VPS

  10. Test laboratories for elementary cells of a solid oxide fuel cell (SOFC); Laboratoire d`essais de cellules elementaires d`une pile a combustible a oxyde solide (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Guerin, F.

    1998-01-01

    The solid oxide furl (SOFC) cell could well be the fuel most suited to stationary applications. Its high working temperature allows it to high value heat which can be used to increase electrical output (by the addition of a gas turbine), or to produce steam for heating or an industrial process. test laboratory for electrochemical cells has been created to test elementary cells whose dimensions do not exceed 5 x 5 cm. The SOFC, consisting of a ceramic sheet, is maintained in an oven at around 900 deg. C. It can produce a maximum continuous current of 25 A at a voltage of 0.7 V on an electronic charge. Each test lasts at least 500 hours. Investigation of the prototype cells is intended to establish their electrochemical characteristics: activity, ionic and electronic conductivity, polarization curve stability behaviour under fast transient electronic regime. In parallel, modelings are performed and will be validated by these different tests results

  11. Investigations on autothermal reforming of kerosene Jet A-1 for supplying solid oxide fuel cells (SOFC); Untersuchungen zur autothermen Reformierung von Kerosin Jet A-1 zur Versorgung oxidkeramischer Festelektrolyt-Brennstoffzellen (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Lenz, B.

    2007-01-25

    The auxiliary power unit of commercial aircraft is a gas turbine producing electric power with an efficiency of 18 %. This APU can be replaced by a fuel cell system, consisting of an autothermal kerosene reformer and a solid oxide fuel cell (SOFC). The fuel is kerosene Jet A-1. The autothermal reforming of Jet A-1 is practically investigated under variation of steam-to-carbon-ratio, air ratio, space velocity, time in operation and reactor pressure on commercial catalysts. Using stationary system simulation the thermodynamic processes of the device is investigated. Finally, the autothermal reformer and the SOFC consisting of 14 cells are coupled. During this test series, I-V-characteristics are measured, fuel utilisation is calculated and the self-sufficient system operation is shown. (orig.)

  12. Preparation of cathode materials for solid oxide solid fuel (SOFC) using gelatin; Preparacao de materiais catodicos para celulas a combustivel de oxido solido (SOFC) atraves do uso de gelatina

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.M.; Aquino, F. de M.; Macedo, D.A. de; Sa, A.M.; Galvao, G.O., E-mail: rinaldo_mendesa@hotmail.com [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)

    2016-07-01

    Fuel cells are electrochemical devices that convert chemical energy into electrical energy. These devices are basically divided into interconnectors, electrolyte, anode, and cathode. Recently, studies of improvements in microstructural and morphological properties of calcium cobaltate (Ca{sub 3}Co{sub 4}O{sub 9}, C349) has been made regarding its potential use as SOFC cathode for intermediate temperature. Gelatin has proven to be effective as a polymerizing agent in the synthesis of nanocrystalline materials. This work reports the synthesis and characterization of the C349 cathode using commercial gelatin. The structural properties of the material were determined by X-ray diffraction (XRD). Morphological characterization was performed by scanning electron microscopy (SEM). The results showed the formation of the crystalline phase at 900 °C, indicating the effectiveness of the gelatin in the preparation of cathodes for SOFC. (author)

  13. Performance-Microstructure Relations in Ni/CGO Infiltrated Nb-doped SrTiO3 SOFC Anodes

    DEFF Research Database (Denmark)

    Ramos, Tania; Bernuy-Lopez, Carlos; Reddy Sudireddy, Bhaskar

    2012-01-01

    Nb-doped SrTiO3 solid oxide fuel cell (SOFC) anodes, infiltrated with CGO/Ni, were investigated by electrochemical impedance spectroscopy (EIS) and high resolution microscopy techniques, upon varying production and testing parameters. The electrochemical analysis involved a combination of distrib......Nb-doped SrTiO3 solid oxide fuel cell (SOFC) anodes, infiltrated with CGO/Ni, were investigated by electrochemical impedance spectroscopy (EIS) and high resolution microscopy techniques, upon varying production and testing parameters. The electrochemical analysis involved a combination...... of distribution of relaxation times (DRT) and complex non-linear least squares (CNLS) fitting routine. These electrodes were studied as singlephase or as composites with 8YSZ. Sr0.94Ti0.9Nb0.1O3-δ/ 10 vol.% 8YSZ composite infiltrated electrodes were the best overall performers, with enhanced performance stability...

  14. Operating Point Optimization of a Hydrogen Fueled Hybrid Solid Oxide Fuel Cell-Steam Turbine (SOFC-ST Plant

    Directory of Open Access Journals (Sweden)

    Juanjo Ugartemendia

    2013-09-01

    Full Text Available This paper presents a hydrogen powered hybrid solid oxide fuel cell-steam turbine (SOFC-ST system and studies its optimal operating conditions. This type of installation can be very appropriate to complement the intermittent generation of renewable energies, such as wind generation. A dynamic model of an alternative hybrid SOFC-ST configuration that is especially suited to work with hydrogen is developed. The proposed system recuperates the waste heat of the high temperature fuel cell, to feed a bottoming cycle (BC based on a steam turbine (ST. In order to optimize the behavior and performance of the system, a two-level control structure is proposed. Two controllers have been implemented for the stack temperature and fuel utilization factor. An upper supervisor generates optimal set-points in order to reach a maximal hydrogen efficiency. The simulation results obtained show that the proposed system allows one to reach high efficiencies at rated power levels.

  15. Feasibility study on combined use of residential SOFC cogeneration system and plug-in hybrid electric vehicle from energy-saving viewpoint

    International Nuclear Information System (INIS)

    Wakui, Tetsuya; Wada, Naohiro; Yokoyama, Ryohei

    2012-01-01

    Highlights: ► Optimal operational planning for combined use of SOFC-CGS and PHEV is conducted. ► Charging PHEV with SOFC-CGS increases electric capacity factor of SOFC-CGS. ► Energy-saving effect of combined use is higher than that of their separate use. ► Combined use provides energy savings in both residential and transport sectors. - Abstract: The energy-saving effect of a combined use of a residential solid oxide fuel cell cogeneration system (SOFC-CGS) that adopts a continuous operation, and a plug-in hybrid electric vehicle (PHEV) is discussed by optimal operational planning based on mixed-integer linear programming. This combined use aims to increase the electric capacity factor of the SOFC-CGS by charging the PHEV using the SOFC-CGS electric power output late at night, and targets the application in regions where the reverse power flow from residential cogeneration systems to commercial electric power systems is not permitted, like in Japan. The optimal operation patterns of the combined use of 0.7-kWe SOFC-CGS and PHEV for a simulated energy demand with a sampling time of 1 h and various daily running distances of the PHEV show that this combined use increases the electric capacity factor of the SOFC-CGS and saves more energy in comparison with their separate use in which the SOFC-CGS is used but the PHEV is charged only with purchased electric power. Furthermore, it is found that at the PHEV daily running distance of 12 km/d, the reduction rate of the annual primary energy consumption for this combined use increases by up to 3.7 percentage points relative to their separate use. Consequently, this feasibility study reveals that the combined use of the SOFC-CGS and PHEV provides the synergistic effect on energy savings in the residential and transport sectors. For the practical use, simulation scenarios considering the energy demand fluctuations with short periods and real-time pricing of the purchased electric power must be considered as future

  16. Thermodynamic and thermoeconomic analysis of a system with biomass gasification, solid oxide fuel cell (SOFC) and Stirling engine

    International Nuclear Information System (INIS)

    Rokni, Masoud

    2014-01-01

    Thermodynamic and thermoeconomic investigations of a small-scale integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120 kW e have been performed. Woodchips are used as gasification feedstock to produce syngas, which is then utilized to feed the anode side of the SOFC stacks. A thermal efficiency of 0.424 LHV (lower heating value) for the plant is found to use 89.4 kg/h of feedstock to produce the above mentioned electricity. Thermoeconomic analysis shows that the production price of electricity is 0.1204 $/kWh. Furthermore, hot water is considered as a by-product, and the cost of hot water is found to be 0.0214 $/kWh. When compared to other renewable systems of similar scales, this result shows that if both SOFC and Stirling engine technology enter the commercialization phase, then they can deliver electricity at a cost that is competitive with the corresponding renewable systems of the same size. - Highlights: • A 120 kW e integrated gasification SOFC–Stirling CHP is presented. • Effect of important parameters on plant characteristic and economy are studied. • A modest thermal efficiency of 0.41 is found after thermoeconomic optimization. • Reducing stack numbers cuts cost of electricity at expense of thermal efficiency. • The plant cost is estimated to be about 3433 $/kW when disposal costs are neglected

  17. High temperature phase transition in SOFC anodes based on Sr2MgMoO6-δ

    International Nuclear Information System (INIS)

    Marrero-Lopez, D.; Pena-Martinez, J.; Ruiz-Morales, J.C.; Martin-Sedeno, M.C.; Nunez, P.

    2009-01-01

    The double perovskite Sr 2 MgMoO 6-δ has been recently reported as an efficient anode material for solid oxide fuel cells (SOFCs). In the present work, this material have been investigated by high temperature X-ray diffraction (XRD), differential scanning calorimetry (DSC) and impedance spectroscopy to further characterise its properties as SOFC anode. DSC and XRD measurements indicate that Sr 2 MgMoO 6-δ exhibits a reversible phase transition around 275 deg. C from triclinic (I1-bar) with an octahedral tilting distortion to cubic (Fm3-barm) without octahedral distortion. This phase transition is continuous with increasing temperature without any sudden cell volume change during the phase transformation. The main effect of the phase transformation is observed in the electrical conductivity with a change in the activation energy at low temperature. La 3+ and Fe-substituted Sr 2 MgMoO 6-δ phases were also investigated, however these materials are unstable under oxidising conditions due to phase segregations above 600 deg. C. - Graphical abstract: The double perovskite Sr 2 MgMoO 6 , recently proposed as an efficient SOFC anode for direct hydrocarbon oxidation, exhibits a reversible structural phase transition from triclinic to cubic at 275 deg. C.

  18. Predicting the ultimate potential of natural gas SOFC power cycles with CO2 capture - Part A: Methodology and reference cases

    Science.gov (United States)

    Campanari, Stefano; Mastropasqua, Luca; Gazzani, Matteo; Chiesa, Paolo; Romano, Matteo C.

    2016-08-01

    Driven by the search for the highest theoretical efficiency, in the latest years several studies investigated the integration of high temperature fuel cells in natural gas fired power plants, where fuel cells are integrated with simple or modified Brayton cycles and/or with additional bottoming cycles, and CO2 can be separated via chemical or physical separation, oxy-combustion and cryogenic methods. Focusing on Solid Oxide Fuel Cells (SOFC) and following a comprehensive review and analysis of possible plant configurations, this work investigates their theoretical potential efficiency and proposes two ultra-high efficiency plant configurations based on advanced intermediate-temperature SOFCs integrated with a steam turbine or gas turbine cycle. The SOFC works at atmospheric or pressurized conditions and the resulting power plant exceeds 78% LHV efficiency without CO2 capture (as discussed in part A of the work) and 70% LHV efficiency with substantial CO2 capture (part B). The power plants are simulated at the 100 MW scale with a complete set of realistic assumptions about fuel cell (FC) performance, plant components and auxiliaries, presenting detailed energy and material balances together with a second law analysis.

  19. Development of electrical efficiency measurement techniques for 10 kW-class SOFC system: Part II. Uncertainty estimation

    International Nuclear Information System (INIS)

    Tanaka, Yohei; Momma, Akihiko; Kato, Ken; Negishi, Akira; Takano, Kiyonami; Nozaki, Ken; Kato, Tohru

    2009-01-01

    Uncertainty of electrical efficiency measurement was investigated for a 10 kW-class SOFC system using town gas. Uncertainty of heating value measured by the gas chromatography method on a mole base was estimated as ±0.12% at 95% level of confidence. Micro-gas chromatography with/without CH 4 quantification may be able to reduce uncertainty of measurement. Calibration and uncertainty estimation methods are proposed for flow-rate measurement of town gas with thermal mass-flow meters or controllers. By adequate calibrations for flowmeters, flow rate of town gas or natural gas at 35 standard litters per minute can be measured within relative uncertainty ±1.0% at 95 % level of confidence. Uncertainty of power measurement can be as low as ±0.14% when a precise wattmeter is used and calibrated properly. It is clarified that electrical efficiency for non-pressurized 10 kW-class SOFC systems can be measured within ±1.0% relative uncertainty at 95% level of confidence with the developed techniques when the SOFC systems are operated relatively stably

  20. Development and fabrication of a new concept planar-tubular solid oxide fuel cell (PT-SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.; Chen, F. [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026 Anhui (China); Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208 (United States); Ding, D. [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Gao, J. [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026 Anhui (China)

    2011-06-15

    The paper reports a new concept of planar-tubular solid oxide fuel cell (PT-SOFC). Emphasis is on the fabrication of the required complex configuration of Ni-yttria-stabilised zirconia (YSZ) porous anode support by tert-butyl alcohol (TBA) based gelcasting, particularly the effects of solid loading, amounts of monomers and dispersant on the rheological behaviour of suspension, the shrinkage of a wet gelcast green body upon drying, and the properties of final sample after sintering at 1350 C and reduction from NiO-YSZ to Ni-YSZ. The results show that the gelcasting is a powerful method for preparation of the required complex configuration anode support. The anode support resulted from an optimised suspension with the solid loading of 25 vol% has uniform microstructure with 37% porosity, bending strength of 44 MPa and conductivity of 300 S cm{sup -} {sup 1} at 700 C, meeting the requirements for an anode support of SOFC. Based on the as-prepared anode support, PT-SOFC single cell of Ni-YSZ/YSZ/LSCF has been fabricated by slurry coating and co-sintering technique. The cell peak power density reaches 63, 106 and 141 mW cm {sup -} {sup 2} at 700, 750 and 800 C, respectively, using hydrogen as fuel and ambient air as oxidant. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Review of the micro-tubular solid oxide fuel cell. Part I. Stack design issues and research activities

    Energy Technology Data Exchange (ETDEWEB)

    Lawlor, V. [Department of Eco-Energy Engineering, Upper Austrian University of Applied Sciences, A-4600 Wels (Austria); Department of Manufacturing and Mechanical Engineering, Dublin City University, Dublin 9 (Ireland); Griesser, S. [Department of Eco-Energy Engineering, Upper Austrian University of Applied Sciences, A-4600 Wels (Austria); Buchinger, G. [eZelleron GmbH, Collenbusch str. 22, 01324 Dresden (Germany); Olabi, A.G. [Department of Manufacturing and Mechanical Engineering, Dublin City University, Dublin 9 (Ireland); Cordiner, S. [Dipartimento di Ingegneria Meccanica - Universita di Roma Tor Vergata (Italy); Meissner, D. [Department of Eco-Energy Engineering, Upper Austrian University of Applied Sciences, A-4600 Wels (Austria); Department of Material Science, Tallinn University of Technology, Ehitajate 19086 (Estonia)

    2009-09-05

    Fuel cells are devices that convert chemical energy in hydrogen enriched fuels into electricity electrochemically. Micro-tubular solid oxide fuel cells (MT-SOFCs), the type pioneered by K. Kendall in the early 1990s, are a variety of SOFCs that are on the scale of millimetres compared to their much larger SOFC relatives that are typically on the scale of tens of centimetres. The main advantage of the MT-SOFC, over its larger predecessor, is that it is smaller in size and is more suitable for rapid start up. This may allow the SOFC to be used in devices such as auxiliary power units, automotive power supplies, mobile electricity generators and battery re-chargers. The following paper is Part I of a two part series. Part I will introduce the reader to the MT-SOFC stack and its applications, indicating who is researching what in this field and also specifically investigate the design issues related to multi-cell reactor systems called stacks. Part II will review in detail the combinations of materials and methods used to produce the electrodes and electrolytes of MT-SOFC's. Also the role of modelling and validation techniques used in the design and improvement of the electrodes and electrolytes will be investigated. A broad range of scientific and engineering disciplines are involved in a stack design. Scientific and engineering content has been discussed in the areas of thermal-self-sustainability and efficiency, sealing technologies, manifold design, electrical connections and cell performance optimisation. (author)

  2. Development of a high-performance composite cathode for LT-SOFC

    Science.gov (United States)

    Lee, Byung Wook

    Solid Oxide Fuel Cell (SOFC) has drawn considerable attention for decades due to its high efficiency and low pollution, which is made possible since chemical energy is directly converted to electrical energy through the system without combustion. However, successful commercialization of SOFC has been delayed due to its high production cost mainly related with using high cost of interconnecting materials and the other structural components required for high temperature operation. This is the reason that intermediate (IT) or low temperature (LT)-SOFC operating at 600~800°C or 650°C and below, respectively, is of particular significance because it allows the wider selection of cheaper materials such as stainless steel for interconnects and the other structural components. Also, extended lifetime and system reliability are expected due to less thermal stress through the system with reduced temperature. More rapid start-up/shut-down procedure is another advantage of lowering the operating temperatures. As a result, commercialization of SOFC will be more viable. However, there exists performance drop with reduced operating temperature due to increased polarization resistances from the electrode electrochemical reactions and decreased electrolyte conductivity. Since ohmic polarization of the electrolyte can be significantly reduced with state-of-the art thin film technology and cathode polarization has more drastic effect on total SOFC electrochemical performance than anode polarization as temperature decreases, development of the cathode with high performance operating at IT or LT range is thus essential. On the other hand, chemical stability of the cathode and its chemical compatibility with the electrolyte should also be considered for cathode development since instability and incompatibility of the cathode will also cause substantial performance loss. Based on requirements of the cathode mentioned above, in this study, several chemico-physical approaches were

  3. Long-term commitment of Japanese gas utilities to PAFCs and SOFCs

    Science.gov (United States)

    Matsumoto, Kiyokazu; Kasahara, Komei

    Tokyo Gas and Osaka Gas have been committed to addressing the energy- and environment-related issues of Japan through promotion of natural gas, an energy friendly to the environment. Being aware of the diversifying market needs (e.g. efficient energy utilization, rising demand for electricity, etc.), active efforts have been made in marketing gas-fired air-conditioning and co-generation systems. In this process, a high priority has also been placed on fuel cells, particularly for realizing their market introduction. Since their participation in the TARGET Program in USA in 1972, the two companies have been involved with the field testing and operation of phosphoric acid fuel cells (PAFCs), whose total capacity has amounted to 12.4 MW. The two companies have played a vital role in promoting and accelerating fuel cell development through the following means: (1) giving incentives to manufacturers through purchase of units and testing, (2) giving feedback on required specifications and technical problems in operation, and (3) verifying and realizing long-term operation utilizing their maintenance techniques. It has been expected that the primary goal of the cumulative operation time of 40 000 h shall be achieved in the near future. Work has also been in progress to develop SOFC. In the joint R&D of a 25-kW solid oxide fuel cell (SOFC) with Westinghouse, the record operation time of 13 000 h has been achieved. Though still twice as much as the average price of competing equipment, the commercialization of PAFCs is close at hand. By utilizing government spending and subsidies for field testing, work will be continued to verify reliability and durability of PAFCs installed at users' sites. These activities have been expected to contribute to realizing economically viable systems and enhance market introduction. The superlative advantages of fuel cells, particularly their environment-friendly qualities, should be best taken advantage of at an appropriate time. In

  4. Poisoning of Ni-Based anode for proton conducting SOFC by H2S, CO2, and H2O as fuel contaminants

    Science.gov (United States)

    Sun, Shichen; Awadallah, Osama; Cheng, Zhe

    2018-02-01

    It is well known that conventional solid oxide fuel cells (SOFCs) based on oxide ion conducting electrolyte (e.g., yttria-stabilized zirconia, YSZ) and nickel (Ni) - ceramic cermet anodes are susceptible to poisoning by trace amount of hydrogen sulfide (H2S) while not significantly impacted by the presence of carbon dioxide (CO2) and moisture (H2O) in the fuel stream unless under extreme operating conditions. In comparison, the impacts of H2S, CO2, and H2O on proton-conducting SOFCs remain largely unexplored. This study aims at revealing the poisoning behaviors caused by H2S, CO2, and H2O for proton-conducting SOFCs. Anode-supported proton-conducting SOFCs with BaZe0.1Ce0.7Y0.1Yb0.1O3 (BZCYYb) electrolyte and Ni-BZCYYb anode and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) cathode as well as Ni-BZCYYb/BZCYYb/Ni-BZCYYb anode symmetrical cells were subjected to low ppm-level H2S or low percentage-level CO2 or H2O in the hydrogen fuel, and the responses in cell electrochemical behaviors were recorded. The results suggest that, contrary to conventional SOFCs that show sulfur poisoning and CO2 and H2O tolerance, such proton-conducting SOFCs with Ni-BZCYYb cermet anode seem to be poisoned by all three types of "contaminants". Beyond that, the implications of the experimental observations on understanding the fundamental mechanism of anode hydrogen electrochemical oxidation reaction in proton conducting SOFCs are also discussed.

  5. Inkjet printing and inkjet infiltration of functional coatings for SOFCs fabrication

    Directory of Open Access Journals (Sweden)

    Tomov Rumen I.

    2016-01-01

    Full Text Available Inkjet printing fabrication and modification of electrodes and electrolytes of SOFCs were studied. Electromagnetic print-heads were utilized to reproducibly dispense droplets of inks at rates of several kHz on demand. Printing parameters including pressure, nozzle opening time and drop spreading were studied in order to optimize the inks jetting and delivery. Scanning electron microscopy revealed highly conformal ~ 6-10 μm thick dense electrolyte layers routinely produced on cermet and metal porous supports. Open circuit voltages ranging from 0.95 to 1.01 V, and a maximum power density of ~180 mW.cm−2 were measured at 750 °C on Ni-8YSZ/YSZ/LSM single cell 50×50 mm in size. The effect of anode and cathode microstructures on the electrochemical performance was investigated. Two - step fabrication of the electrodes using inkjet printing infiltration was implemented. In the first step the porous electrode scaffold was created printing suspension composite inks. During the second step inkjet printing infiltration was utilized for controllable loading of active elements and a formation of nano-grid decorations on the scaffolds radically reducing the activation polarization losses of both electrodes. Symmetrical cells of both types were characterized by impedance spectroscopy in order to reveal the relation between the microstructure and the electrochemical performance.

  6. Plasma-Sprayed LSM Protective Coating on Metallic Interconnect of SOFC

    Directory of Open Access Journals (Sweden)

    Jia-Wei Chen

    2017-12-01

    Full Text Available In this study, a (La0.8Sr0.20.98MnO3 protective layer was prepared on the C276, Crofer22 APU, SUS304, and SUS430 alloys by the atmospheric plasma spraying technique (APS. The oxidation behavior and electrical property of these metal alloys have been investigated isothermally at 800 °C in air for up to 300 h. Results showed that the ferritic steels transform into MnCr2O4 spinels and a Cr2O3 layer during isothermal oxidation. The C276 alloy formed NiCr2O4 and FeCr2O4 layers; these are protective and act as an effective barrier against chromium migration into the outer oxide layer, and the alloy demonstrated good oxidation resistance and a reasonable match to the coefficient of thermal expansion of the substrate and a low-oxide scale area-specific resistance. The ASR effects on the formation of oxide scale have been investigated, and the ASR of coated samples was below 0.024 Ω·cm2. It has good electrical conductivity for SOFC in long-term use.

  7. Developing Cost-Effective Dense Continuous SDC Barrier Layers for SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Hoang Viet P.; Hardy, John S.; Coyle, Christopher A.; LU, Zigui; Stevenson, Jeffry W.

    2017-12-04

    Significantly improved performance during electrochemical testing of a cell with a dense continuous pulsed laser deposited (PLD) samarium doped ceria (SDC) layer spurred investigations into the fabrication of dense continuous SDC barrier layers by means of cost-effective deposition using screen printing which is amenable to industrial production of SOFCs. Many approaches to improve the SDC density have been explored including the use of powder with reduced particle sizes, inks with increased solids loading, and doping with sintering aids (1). In terms of sintering aids, dopants like Mo or binary systems of Mo+Cu or Fe+Co greatly enhance SDC sinterability. In fact, adding dopants to a screen printed, prefired, porous SDC layer made it possible to achieve a dense continuous barrier layer atop the YSZ electrolyte without sintering above 1200°C. Although the objective of fabricating a dense continuous layer was achieved, additional studies have been initiated to improve the cell performance. Underlying issues with constrained sintering and dopant-enhanced ceria-zirconia solid solubility are also addressed in this paper.

  8. Performance simulation of planar SOFC using mixed hydrogen and carbon monoxide gases as fuel

    Energy Technology Data Exchange (ETDEWEB)

    Inui, Y. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan)]. E-mail: inui@eee.tut.ac.jp; Urata, A. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan); Ito, N. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan); Nakajima, T. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan); Tanaka, T. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan)

    2006-08-15

    The authors investigate in detail the influence of the mixing ratio of hydrogen and carbon monoxide in the fuel on the cell performance of the SOFC through numerical simulations for a single cell plate of the co-flow type planar cell. It is made clear that the cell performance is almost the same and excellent, independent of the mixing ratio of hydrogen and carbon monoxide under the nominal operating condition. The electromotive force of the hydrogen rich fuel gas is a little higher than that of the carbon monoxide rich fuel gas. The internal voltage drop in the cell decreases as the fraction of carbon monoxide becomes high. Since the value of the single cell voltage is determined by the balance of these two phenomena, the lowering of the electromotive force is dominant and the single cell voltage of the hydrogen rich fuel gas is higher when the inlet gas temperature is high, whereas the voltage drop reduction is dominant and the single cell voltage of the carbon monoxide rich fuel gas is higher when the temperature is low. The effect of the additional gases of water vapor and carbon dioxide is restricted to the single cell voltage shift, and the qualitative dependence of the single cell voltage on the inlet gas temperature is determined by the mixing ratio of hydrogen and carbon monoxide.

  9. Enhancement of SOFC Cathode Electrochemical Performance Using Multi-Phase Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Dane [Univ. of Wisconsin, Madison, WI (United States)

    2015-09-30

    This work explored the use of oxide heterostructures for enhancing the catalytic and degradation properties of solid oxide fuel cell (SOFC) cathode electrodes. We focused on heterostructures of Ruddlesden-Popper and perovskite phases. Building on previous work showing enhancement of the Ruddlesden-Popper (La,Sr)2CoO4 / perovskite (La,Sr)CoO3 heterostructure compared to pure (La,Sr)CoO3 we explored the application of related heterostructures of Ruddlesden-Popper phases on perovskite (La,Sr)(Co,Fe)O3. Our approaches included thin-film electrodes, physical and electrochemical characterization, elementary reaction kinetics modeling, and ab initio simulations. We demonstrated that Sr segregation to surfaces is likely playing a critical role in the performance of (La,Sr)CoO3 and (La,Sr)(Co,Fe)O3 and that modification of this Sr segregation may be the mechanism by which Ruddlesden-Popper coatings enhance performances. We determined that (La,Sr)(Co,Fe)O3 could be enhanced in thin films by about 10× by forming a heterostructure simultaneously with (La,Sr)2CoO4 and (La,Sr)CoO3. We hope that future work will develop this heterostructure for use as a bulk porous electrode.

  10. Impedance analysis of a disk-type SOFC using doped lanthanum gallate under power generation

    Science.gov (United States)

    Kato, Tohru; Nozaki, Ken; Negishi, Akira; Kato, Ken; Monma, Akihiko; Kaga, Yasuo; Nagata, Susumu; Takano, Kiyonami; Inagaki, Toru; Yoshida, Hiroyuki; Hosoi, Kei; Hoshino, Koji; Akbay, Taner; Akikusa, Jun

    Impedance measurements were carried out under practical power generation conditions in a disk-type SOFC, which may be utilized as a small-scale power generator. The tested cell was composed of doped lanthanum gallate (La 0.8Sr 0.2Ga 0.8Mg 0.15Co 0.05O 3- δ) as the electrolyte, Sm 0.5Sr 0.5CoO 3 as the cathode electrode and Ni/Ce 0.8Sm 0.2O 2 cermet as the anode electrode. The cell impedance was measured between 10 mHz and 10 kHz by varying the fuel utilization and gas flow rate and plotted in complex impedance diagrams. The observed impedance shows a large semi-circular pattern on the low frequency side. The semi-circular impedance, having a noticeably low characteristic frequency between 0.13 and 0.4 Hz, comes from the change in gas composition, originally caused by the cell reaction. The change in impedance with the fuel utilization (load current) and the gas flow rate agreed qualitatively well with the theoretical predictions from a simulation. This impedance was dominant under high fuel-utilization power-generation conditions. The impedance, which described the activation polarizations in the electrode reactions, was comparatively small and scarcely changed with the change in fuel utilization (load current) and gas flow rate.

  11. Operational planning of an independent microgrid containing tidal power generators, SOFCs, and photovoltaics

    International Nuclear Information System (INIS)

    Obara, Shin’ya; Kawai, Masahito; Kawae, Osamu; Morizane, Yuta

    2013-01-01

    Highlights: ► The characteristics of a microgrid composed of SOFCs and tidal power generators were investigated. ► The CO 2 emissions of this microgrid were calculated based on an oceanographic investigation. ► The frequency and wave form quality of the electric power system were investigated. ► The voltage regulation and reactive power control of the electric power system need to be improved. -- Abstract: The development of local energy systems is important to curtailing global warming and improving public safety. Therefore, in this work, the basic performance of an independent microgrid consisting of tidal power generators, photovoltaics, fuel cells, and heat pumps to locally produce energy for local consumption was analyzed. Fast tidal currents near inlets that join lakes to the sea were converted into electrical energy via a three-phase synchronized generator connected to Darius water turbines. On the basis of the results of an oceanographic survey, the production of electricity and the CO 2 emissions of each generator were calculated using balanced equations for electricity and heat. The calculations indicated that 33% of the CO 2 emissions were associated with the energy supplied through conventional methods during the summer season. Although the frequency and waveform of the electricity of the microgrid were high quality, improvement in the voltage regulation was still required.

  12. Anode-supported SOFC operated under single-chamber conditions at intermediate temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Morales, M.; Roa, J.J.; Segarra, M. [Department of Materials Science and Metallurgical Engineering, University of Barcelona, E-08028, Barcelona (Spain); Capdevila, X.G. [Center of Design and Optimization in Avanced Materials, Parc Cientific of Barcelona, E-08028, Barcelona (Spain); Pinol, S. [Institute of Materials Science of Barcelona (CSIC), Campus of the UAB, Bellaterra E-08193, Barcelona (Spain)

    2011-02-15

    Anode-supported SOFC was fabricated using gadolinia doped ceria (GDC) as the electrolyte (15 {mu}m of thickness), Ni-GDC as the anode and La{sub 0.5}Sr{sub 0.5}CoO{sub 3-{delta}}-GDC as the cathode. Catalytic activities of the electrodes and electrical properties of the cell were determined, using mixtures of methane + air, under single-chamber conditions. This work assessed with special and wide emphasis the effect of temperature, gas composition and total flow rate on the cell performance. As a result, operational temperature range of the fuel cell was approximately between 700 and 800 C, which agrees with the results corresponding to the catalytic activities of electrodes. While Ni-GDC anode was enough active towards methane partial oxidation at cell temperatures higher than 700 C, the LSC-GDC cathode was enough inactive towards partial and total oxidation of methane at cell temperatures lower than 800 C. Under optimised gas compositions (CH{sub 4}/O{sub 2}) ratio (1) and total flow rate (530 mL min {sup -1}), power densities of 145 and 235 mW cm {sup -2} were obtained at 705 and 764 C, respectively. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Small Scale SOFC Demonstration Using Bio-Based and Fossil Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Petrik, Michael [Technology Management Inc., Cleveland, OH (United States); Ruhl, Robert [Technology Management Inc., Cleveland, OH (United States)

    2012-05-01

    Technology Management, Inc. (TMI) of Cleveland, Ohio, has completed the project entitled Small Scale SOFC Demonstration using Bio-based and Fossil Fuels. Under this program, two 1-kW systems were engineered as technology demonstrators of an advanced technology that can operate on either traditional hydrocarbon fuels or renewable biofuels. The systems were demonstrated at Patterson's Fruit Farm of Chesterland, OH and were open to the public during the first quarter of 2012. As a result of the demonstration, TMI received quantitative feedback on operation of the systems as well as qualitative assessments from customers. Based on the test results, TMI believes that > 30% net electrical efficiency at 1 kW on both traditional and renewable fuels with a reasonable entry price is obtainable. The demonstration and analysis provide the confidence that a 1 kW entry-level system offers a viable value proposition, but additional modifications are warranted to reduce sound and increase reliability before full commercial acceptance.

  14. Analyses of microstructural and elastic properties of porous SOFC cathodes based on focused ion beam tomography

    Science.gov (United States)

    Chen, Zhangwei; Wang, Xin; Giuliani, Finn; Atkinson, Alan

    2015-01-01

    Mechanical properties of porous SOFC electrodes are largely determined by their microstructures. Measurements of the elastic properties and microstructural parameters can be achieved by modelling of the digitally reconstructed 3D volumes based on the real electrode microstructures. However, the reliability of such measurements is greatly dependent on the processing of raw images acquired for reconstruction. In this work, the actual microstructures of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathodes sintered at an elevated temperature were reconstructed based on dual-beam FIB/SEM tomography. Key microstructural and elastic parameters were estimated and correlated. Analyses of their sensitivity to the grayscale threshold value applied in the image segmentation were performed. The important microstructural parameters included porosity, tortuosity, specific surface area, particle and pore size distributions, and inter-particle neck size distribution, which may have varying extent of effect on the elastic properties simulated from the microstructures using FEM. Results showed that different threshold value range would result in different degree of sensitivity for a specific parameter. The estimated porosity and tortuosity were more sensitive than surface area to volume ratio. Pore and neck size were found to be less sensitive than particle size. Results also showed that the modulus was essentially sensitive to the porosity which was largely controlled by the threshold value.

  15. Effect of Gas Pressure on Polarization of SOFC Cathode Prepared by Plasma Spray

    Science.gov (United States)

    Li, Cheng-Xin; Wang, Zhun-Zhun; Liu, Shuai; Li, Chang-Jiu

    2013-06-01

    A cermet-supported tubular SOFC was fabricated using thermal spray. The cell performance was investigated at temperatures from 750 to 900 °C and pressures from 0.1 to 0.5 MPa to examine the effect of operating gas pressure on the cell performance. The influence of gas pressure on the cathodic polarization was studied through the electrochemical impedance approach to examine the controlling electrochemical processes during cell operation. Results show that increasing the operating gas pressure improves the power output performance significantly. When the gas pressure is increased from 0.1 to 0.3 MPa, the maximum power density is increased by a factor of 32% at a temperature of 800 °C. The cathode polarization decreases significantly with the increase of the gas pressure. The electrochemical analysis shows that the main control processes of the cathode reaction are the oxygen species transfer at the three-phase boundary and oxygen diffusion on the surface or in the bulk of the cathode, which are enhanced with increasing gas pressure.

  16. Performance simulation of planar SOFC using mixed hydrogen and carbon monoxide gases as fuel

    International Nuclear Information System (INIS)

    Inui, Y.; Urata, A.; Ito, N.; Nakajima, T.; Tanaka, T.

    2006-01-01

    The authors investigate in detail the influence of the mixing ratio of hydrogen and carbon monoxide in the fuel on the cell performance of the SOFC through numerical simulations for a single cell plate of the co-flow type planar cell. It is made clear that the cell performance is almost the same and excellent, independent of the mixing ratio of hydrogen and carbon monoxide under the nominal operating condition. The electromotive force of the hydrogen rich fuel gas is a little higher than that of the carbon monoxide rich fuel gas. The internal voltage drop in the cell decreases as the fraction of carbon monoxide becomes high. Since the value of the single cell voltage is determined by the balance of these two phenomena, the lowering of the electromotive force is dominant and the single cell voltage of the hydrogen rich fuel gas is higher when the inlet gas temperature is high, whereas the voltage drop reduction is dominant and the single cell voltage of the carbon monoxide rich fuel gas is higher when the temperature is low. The effect of the additional gases of water vapor and carbon dioxide is restricted to the single cell voltage shift, and the qualitative dependence of the single cell voltage on the inlet gas temperature is determined by the mixing ratio of hydrogen and carbon monoxide

  17. Ni-YSZ cermet substrate supported thin SDC and YSZ+SDC bi-layer SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.; Robertson, M.; Deces-Petit, C.; Xie, Y.; Hui, R.; Yick, S.; Styles, E.; Roller, J.; Kesler, O.; Qu, W.; Jankovic, J.; Tang, Z.; Perednis, D.; Maric, R.; Ghosh, D. [National Research Council of Canada, Vancouver, BC (Canada). Inst. for Fuel Cell Innovation

    2005-07-01

    One of the disadvantages of a ceria-based electrolyte is that it becomes a mixed conductor at anode conditions, which causes cell voltage loss and fuel efficiency loss due to internal shorting. Chemical and mechanical stability is another concern for long-term service. To lower manufacturing costs, efforts have been made to bring proven semiconductor manufacturing technology to Solid Oxide Fuel Cells (SOFCs). This study employed Tape casting of cermet substrates, Screen-printing of functional layers and Co-firing of cell components (TSC) to fabricate nickel (Ni)-cermet supported cells with mainly ceria-based thin electrolytes. Ni-Yttria-Stabilized Zirconia (YSZ) cermet supported cell with Samaria Doped Ceria (SDC) single layer electrolytes and YSZ+SDC bi-layer electrolytes were successfully developed for low-temperature performance characterization. The elemental distribution at the cell interface was mapped and the electrochemical performance of the cells was recorded. Many high-Zr-content micro-islands were found on the thin SDC surface. The influence of co-firing temperature and thin-film preparation methods on the Zr-islands' appearance was also investigated. Using in-situ sintered cathodes, high performance of the SDC cells was obtained. It was concluded that the bi-layer cells did show higher Open Circuit Voltage (OCV) values, with 1180 mW/cm{sup 2} at 650 degrees C, as well as good performance at 700-800 degrees C, with near OCV value. However, their performance was much lower than those of the SDC cells at low operating temperature. Zr-micro-islands formation on the SDC electrolyte was observed and investigated. 6 refs., 5 tabs., 7 figs.

  18. Deposition of porous cathodes using plasma spray technique for reduced-temperature SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Jankovic, J.; Hui, S.; Roller, J.; Kesler, O.; Xie, Y.; Maric, R.; Ghosh, D. [National Research Council of Canada, Vancouver, BC (Canada). Inst. for Fuel Cell Innovation

    2005-07-01

    Current techniques for Solid Oxide Fuel Cell (SOFC) materials deposition are often expensive and time-consuming. Plasma-spraying techniques provide higher deposition rates, short processing times and control over porosity and composition during deposition. Optimum plasma spraying for lanthanum based cathode materials were discussed. Plasma-spraying was used to deposit cathode materials onto ceramic and stainless steel substrates to obtain highly porous structures. Lanthanum cathode materials with composition of La{sub 0.6}Sr{sub 0.4}C{sub 0.2}Fe{sub 0.8}O{sub 3} were employed in the powder form. The powder was prepared from powder precursors with different power formers and binder levels, or from produced single-phase lanthanum powders. The (La{sub 0.8}Sr{sub 0.2}){sub 0.98}MnO{sub 3} cathode material was also processed for comparison purposes. The deposition process was developed to obtain coatings with good bond strength, porosity, film thickness and residual stresses. The phase and microstructure of deposited materials were characterized using X-Ray Diffraction and Scanning Electron Microscopy (SEM). It was concluded that good flow of the powder precursors is achieved by spraying 50-100 um particle size powders and using vibrating feeders. Further processing of the spraying powders was recommended. It was noted that oxide precursors showed greater reactivity among the precursors. The best precursor reactivity and coating morphology was obtained using 40 volume per cent of graphite pore former, incorporated into the precursor mixture during wet ball milling. It was concluded that higher power levels and larger distances between the plasma gun and the substrate result in coatings with the highest porosities and best phase compositions. 5 refs., 1 tab., 6 figs.

  19. Electrically conducting perovskites for SOFC and catalysis. Preparation characterization and testing

    Energy Technology Data Exchange (ETDEWEB)

    Gordes, P

    1998-12-31

    Solid oxide fuel cells offer the possibility of high efficiency and low pollution energy source. A fuel cell converts chemical energy directly to electricity without combustion as an intermediate step. H{sub 2}, CO or hydrocarbons can be used as fuel gas. At present the main problems in developing a commercial SOFC are related to the air electrode and interconnect. Commercial air electrode and interconnect materials are still not on the market. This dissertation concerns the following main tasks: 1. A theoretical part on the co-optimization of electronic and catalytic properties of perovskites (ABO{sub 3}) where the A position is occupied by mixed rare earth or alkaline earth metal (Ca, Sr, Ba, La, etc) and the B position is occupied by a mixture of transition metals (Mn, Fe, Co, Ni, Cr, etc). 2. Optimization of the drip pyrolysis method and fabrication of high quality perovskite powders of selected compositions for further studies. This work involves a detailed characterization of powders prepared in terms of phase homogeneity, crystallite size, agglomeration, chemical composition etc. 3. Development of the necessary processing technology for fabrication of shaped samples with a closely controlled porosity and pore size distribution. This work involves development of a suitable shaping process (uniaxial pressing, extrusion, tape casting), and a detailed study of the phase evolution and densification properties of the powders as a function of temperature. 4. Characterization of the prepared perovskite components in terms of phase homogeneity, microstructure, as well as electrical and catalytic properties. 5. Recommendations for future work. (EG) 151 refs.

  20. Manufacturing technology of AS-SOFC prepared with different commercially available precursors

    Directory of Open Access Journals (Sweden)

    Kawalec M.

    2016-01-01

    Full Text Available Fuel cells are devices converting the chemical energy into the electrical energy and heat as result of the electrochemical reaction between gaseous fuel and a gas oxidant in flameless combustion process. Because of omission of thermo-mechanical steps that are present in any traditional energy conversion technology (e.g. gas turbine fuel cells show increased efficiency in comparison. Compact sizes and modular scalability predestines this technology for distributed energy generation including but not limited to renewable energy sources (e.g. wind, solar. Fuel cells technology also addresses other very important part of distributed renewable energy generation. Because of the unreliable energy production rates and the usual for renewable energy sources mismatch between energy supply and demand, some sort of energy storage is needed to store surplus of produced energy and release it when needed. Reversible fuel cells, that generate hydrogen from available surplus of energy and then generate energy from that stored fuel when needed are cheaper and more ecologically friendly alternative to usually used batteries. This technology is still under development, including research at IEn OC CEREL. In the early development of reversible fuel cells, new types of nickel oxide and porosity forming carbon was evaluated for this task. This work compares the electrical and mechanical parameters of SOFC manufactured with JT Backer NiO and Carbon Polska carbon with cells made from other commercially available materials. Based on evaluated quality, purity, availability and cost, following materials were selected for comparison: Novamet NiO, 99,9 % pure, grain size 1-2 µm and Aldrich carbon with parameters similar to graphite used previously. Preliminary tests show clear changes in the microstructural, mechanical and electrical parameters.

  1. Electrically conducting perovskites for SOFC and catalysis. Preparation characterization and testing

    Energy Technology Data Exchange (ETDEWEB)

    Gordes, P.

    1997-12-31

    Solid oxide fuel cells offer the possibility of high efficiency and low pollution energy source. A fuel cell converts chemical energy directly to electricity without combustion as an intermediate step. H{sub 2}, CO or hydrocarbons can be used as fuel gas. At present the main problems in developing a commercial SOFC are related to the air electrode and interconnect. Commercial air electrode and interconnect materials are still not on the market. This dissertation concerns the following main tasks: 1. A theoretical part on the co-optimization of electronic and catalytic properties of perovskites (ABO{sub 3}) where the A position is occupied by mixed rare earth or alkaline earth metal (Ca, Sr, Ba, La, etc) and the B position is occupied by a mixture of transition metals (Mn, Fe, Co, Ni, Cr, etc). 2. Optimization of the drip pyrolysis method and fabrication of high quality perovskite powders of selected compositions for further studies. This work involves a detailed characterization of powders prepared in terms of phase homogeneity, crystallite size, agglomeration, chemical composition etc. 3. Development of the necessary processing technology for fabrication of shaped samples with a closely controlled porosity and pore size distribution. This work involves development of a suitable shaping process (uniaxial pressing, extrusion, tape casting), and a detailed study of the phase evolution and densification properties of the powders as a function of temperature. 4. Characterization of the prepared perovskite components in terms of phase homogeneity, microstructure, as well as electrical and catalytic properties. 5. Recommendations for future work. (EG) 151 refs.

  2. Effect of Sintering Temperature and Applied Load on Anode-Supported Electrodes for SOFC Application

    Directory of Open Access Journals (Sweden)

    Xuan-Vien Nguyen

    2016-08-01

    Full Text Available Anode-supported cells are prepared by a sequence of hot pressing and co-sintering processes for solid oxide fuel cell (SOFC applications. Commercially available porous anode tape (NiO/YSZ = 50 wt %/50 wt %, anode tape (NiO/YSZ = 30 wt %/70 wt %, and YSZ are used as the anode substrate, anode functional layer, and electrolyte layer, respectively. After hot pressing, the stacked layers are then sintered at different temperatures (1250 °C, 1350 °C, 1400 °C and 1450 °C for 5 h in air. Different compressive loads are applied during the sintering process. An (La,SrMnO3 (LSM paste is coated on the post-sintered anode-supported electrolyte surface as the cathode, and sintered at different temperatures (1100 °C, 1150 °C, 1200 °C and 1250 °C for 2 h in air to generate anode-supported cells with dimensions of 60 × 60 mm2 (active reaction area of 50 × 50 mm2. SEM is used to investigate the anode structure of the anode-supported cells. In addition, confocal laser scanning microscopy is used to investigate the roughness of the cathode surfaces. At sintering temperatures of 1400 °C and 1450 °C, there is significant grain growth in the anode. Furthermore, the surface of the cathode is smoother at a firing temperature of 1200 °C. It is also found that the optimal compressive load of 1742 Pa led to a flatness of 168 µm/6 cm and a deformation of 0.72%. The open circuit voltage and power density of the anode-supported cell at 750 °C were 1.0 V and 178 mW·cm−2, respectively.

  3. Análise termodinâmica de um ciclo de potência com célula a combustível sofc e turbina a vapor = Thermodynamic analysis of a power cycle such as SOFC fuel cell and steam turbine

    Directory of Open Access Journals (Sweden)

    Alexandre Sordi

    2006-01-01

    Full Text Available O objetivo deste artigo foi realizar a análise termodinâmica de um sistema híbrido, SOFC / ST (célula a combustível tipo SOFC e turbina a vapor ST. O combustível considerado para a análise foi o gás metano (biogás produzido por meio da digestão anaeróbica de resíduos orgânicos. A metodologia utilizada foi o balanço de energia dosistema SOFC / ST, considerando a reforma interna do metano na célula a combustível, de forma a obter a sua eficiência elétrica. O resultado foi comparado a um ciclo combinado convencional de turbina a gás e turbina a vapor (GT / ST para potências entre 10 MW e 30MW. A eficiência do sistema híbrido SOFC / ST variou de 61% a 66% em relação ao poder calorífico do metano; e a eficiência do ciclo combinado GT / ST variou de 41% a 55% para o mesmo intervalo de potência. Para geração distribuída a célula a combustível SOFC é atecnologia mais eficiente.The objective of this article was to analyze the thermodynamic of ahybrid system, SOFC / ST (SOFC fuel cell and ST steam turbine. The fuel for the analysis was the gas methane (biogas produced through the anaerobic digestion of the organic residues. The utilized methodology was the energy balance of the system SOFC / ST,considering the internal reforming of methane in the fuel cell, in a way to obtain its electric effectiveness. The result was compared to a conventional combined cycle of gas turbine and steam turbine (GT / ST for powers between 10 MW and 30 MW. The efficiency of the hybrid system SOFC / ST varied from 61 to 66% in relation to the lower heating value of methane; and the efficiency of the combined cycle GT / ST varied from 41 to 55% within the same power interval. For distributed generation, the SOFC fuel cell is the most efficienttechnology.

  4. Shape distortion and thermo-mechanical properties of dense SOFC components from green tape to sintered body

    DEFF Research Database (Denmark)

    Teocoli, Francesca; Esposito, Vincenzo; Ni, De Wei

    stresses, which develop a camber in the final sintered body. To analyze the phenomena, shrinkage of SOFC components single layers and camber development of bi-layers were measured in-situ by optical dilatometry. In addition, a thoughtful investigation of the viscoelastic properties of individual layers......Sintering of ceramic materials is a critical process, especially when the components are shaped as multilayer. Microstructural changes and stresses take place in ceramics as single layer from the green stage to the densification stage, leading to shape distortion, delamination and cracks...

  5. Electrical Resistance Measurements and Microstructural Characterization of the Anode/Interconnect Contact in Simulated Anode-Side SOFC Conditions

    DEFF Research Database (Denmark)

    Harthøj, Anders; Alimadadi, Hossein; Holt, Tobias

    2015-01-01

    in phase transformation of the steel and in formation of oxides with a poor electrical conductivity in the anode. In this study, the area specific resistance (ASR) of the steel Crofer 22 APU, in contact with a Ni/YSZ anode with and without a tape casted CeO2 barrier layer was measured in simulated SOFC...... anode conditions at 800◦C. The microstructure in the contact area was characterized using scanning electron microscopy techniques. The ASR was low for the steel in direct contact with the Ni/YSZ anode. Nickel diffusion into the steel resulted in a fine grained zone, which was identified as ferrite...

  6. Comparison of the Degradation of the Polarization Resistance of Symmetrical LSM-YSZ Cells, with Anode Supported Ni-YSZ/YSZ/LSM-YSZ SOFCs

    DEFF Research Database (Denmark)

    Torres da Silva, Iris Maura; Nielsen, Jimmi; Hjelm, Johan

    2009-01-01

    Impedance spectra of a symmetrical cell with SOFC cathodes (LSM-YSZ/YSZ/LSM-YSZ) and an anode supported planar SOFC (Ni-YSZ/YSZ/LSM-YSZ) were collected at OCV at 650{degree sign}C in air (cathode) and humidified (4%) hydrogen (anode), over 155 hours. The impedance was affected by degradation over...... time in the same frequency range for both cells (~10 Hz), possibly indicating that the same physical process was affected in both types of cell. However, deconvolution of the impedance data was not straightforward. When n-values of the constant phase elements in the otherwise identical equivalent...

  7. XPS studies of Mg doped GDC (Ce0.8Gd0.2O2-δ) for IT-SOFC

    Science.gov (United States)

    Tyagi, Deepak; Rao, P. Koteswara; Wani, B. N.

    2018-04-01

    Fuel Cells have gained much attention as efficient and environment friendly device for both stationary as well as mobile applications. For intermediate temperature SOFC (IT-SOFC), ceria based electrolytes are the most promising one, due to their higher ionic conductivity at relatively lower temperatures. Gd doped ceria is reported to be having the highest ionic conductivity. In the present work, Mg is codoped along with Gd and the electronic structure of the constituents is studied by XPS. XPS confirm that the Cerium is present in +4 oxidation state only which indicates that electronic conduction can be completely avoided.

  8. Understanding Oxygen Vacancy Formation, Interaction, Transport, and Strain in SOFC Components via Combined Thermodynamics and First Principles Calculations

    Science.gov (United States)

    Das, Tridip

    Understanding of the vacancy formation, interaction, increasing its concentration and diffusion, and controlling its chemical strain will advance the design of mixed ionic and electronic conductor (MIEC) materials via element doping and strain engineering. This is especially central to improve the performance of the solid oxide fuel cell (SOFC), an energy conversion device for sustainable future. The oxygen vacancy concentration grows exponentially with the temperature at dilute vacancy concentration but not at higher concentration, or even decreases due to oxygen vacancy interaction and vacancy ordered phase change. This limits the ionic conductivity. Using density functional theory (DFT), we provided fundamental understanding on how oxygen vacancy interaction originates in one of the typical MIEC, La1-xSrxFeO3-delta (LSF). The vacancy interaction is determined by the interplay of the charge state of multi-valence ion (Fe), aliovalent doping (La/Sr ratio), the crystal structure, and the oxygen vacancy concentration and/or nonstoichiometry (delta). It was found excess electrons left due to the formation of a neutral oxygen vacancy get distributed to Fe directly connected to the vacancy or to the second nearest neighboring Fe, based on crystal field splitting of Fe 3d orbital in different Fe-O polyhedral coordination. The progressively larger polaron size and anisotropic shape changes with increasing Sr-content resulted in increasing oxygen vacancy interactions, as indicated by an increase in the oxygen vacancy formation energy above a critical delta threshold. This was consistent with experimental results showing that Sr-rich LSF and highly oxygen deficient compositions are prone to oxygen-vacancy-ordering-induced phase transformations, while Sr-poor and oxygen-rich LSF compositions are not. Since oxygen vacancy induced phase transformations, cause a decrease in the mobile oxygen vacancy site fraction (X), both delta and X were predicted as a function of

  9. Controlled deposition and utilization of carbon on Ni-YSZ anodes of SOFCs operating on dry methane

    International Nuclear Information System (INIS)

    Jiao, Yong; Zhang, Liqin; An, Wenting; Zhou, Wei; Sha, Yujing; Shao, Zongping; Bai, Jianping; Li, Si-Dian

    2016-01-01

    Solid oxide fuel cells (SOFCs) are promising power-generation systems to utilize methane or methane-based fuels with a high energy efficiency and low environmental impact. A successive multi-stage process is performed to explore the operation of cells using dry methane or the deposited carbon from methane decomposition as fuel. Stable operation can be maintained by optimizing the fuel supply and current density parameters. An electrochemical impedance analysis suggests that the partial oxidization of Ni can occur at anodes when the carbon fuel is consumed. The stability of cells operated on pure methane is investigated in three operating modes. The cell can run in a comparatively stable state with continuous power output in an intermittent methane supply mode, where the deposition and utilization of carbon is controlled by balancing the fuel supply and consumption. The increase in the polarization resistance of the cell might originate from the small amount of NiO and residual carbon at the anode, which can be removed via an oxidation-and-reduction maintenance process. Based on the above strategy, this work provides an alternative operating mode to improve the stability of direct methane SOFCs and demonstrates the feasibility of its application. - Highlights: • A new strategy to control the deposition and utilization of carbon was developed. • A stable fuel cell operation was obtained with an intermittent fuel supply mode. • Polarization resistance increased due to small amount of NiO and residual carbon.

  10. Obtaining of ceria - samaria - gadolinia ceramics for application as solid oxide fuel cell (SOFC) electrolyte

    International Nuclear Information System (INIS)

    Arakaki, Alexander Rodrigo

    2010-01-01

    Cerium oxide (CeO 2 ) when doped with rare earth oxides has its ionic conductivity enhanced, enabling its use as electrolyte for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC), which is operated in temperatures between 500 e 700 degree C. The most effective additives or dopants for ionic conductivity improvement are (samarium oxide - Sm 2 O 3 ) and gadolinia (gadolinium oxide - Gd 2 O 3 ), fixing the concentration between 10 and 20 molar%. In this work, Ce 0,8 (SmGd) 0,2 O 1,9 powders have been synthesized by hydroxide, carbonate and oxalate coprecipitation routes. The hydrothermal treatment has been studied for powders precipitated with ammonium hydroxide. A concentrate of rare earths containing 90wt% of CeO 2 and other containing 51% of Sm 2 O 3 and 30% of Gd 2 O 3 , both prepared from monazite processing, were used as starting materials. These concentrates were used due the lower cost compared to pure commercial materials and the chemical similarity of others rare earth elements. Initially, the coprecipitation and calcination conditions were defined. The process efficiency was verified by ceramic sinterability evaluation. The results showed that powders calcined in the range of 450 and 800 degree C presented high specific surface area (90 - 150 m 2 .g -1 ) and fluorite cubic structure, indicating the solid solution formation. It was observed, by scanning electron microscopy, that morphology of particles and agglomerates is a function of precipitant agent. The dilatometric analysis indicated the higher rate of shrinkage at temperatures around 1300-1350 degree C. High densification values (>95% TD) was obtained at temperatures above 1400 degree C. Synthesis by hydroxides coprecipitation followed by hydrothermal treatment demonstrated to be a promising route for crystallization of ceria nano powders at low temperatures (200 degree C). High values of specific surface area were reached with the employment of hydrothermal treatment (about 100 m 2 .g -1

  11. Proteic sol-gel synthesis of copper doped misfit Ca-cobaltites with potential SOFC application

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Chrystian G.M. [Materials Science and Engineering Postgraduate Program, UFPB, 58051-900, João Pessoa (Brazil); Silva, Rinaldo M. [Department of Chemical Engineering, UFPB, 58051-900, João Pessoa (Brazil); Aquino, Flávia de M. [Alternative and Renewable Energy Center, UFPB, 58051-900, João Pessoa (Brazil); Raveau, Bernard; Caignaert, Vincent [Laboratoire CRISMAT ENSICAEN UMR CNRS 6508, 6 Boulevard du Maréchal Juin, 14050, Caen Cedex 04 (France); Cesário, Moisés R., E-mail: moises.cesario@ensicaen.fr [Laboratoire CRISMAT ENSICAEN UMR CNRS 6508, 6 Boulevard du Maréchal Juin, 14050, Caen Cedex 04 (France); Macedo, Daniel A., E-mail: damaced@gmail.com [Materials Science and Engineering Postgraduate Program, UFPB, 58051-900, João Pessoa (Brazil)

    2017-02-01

    The present work reports the synthesis, structure and electrochemical assessment of Cu-doped calcium cobaltites as cathode materials for solid oxide fuel cells (SOFCs). Powders of composition Ca{sub 3−x}Cu{sub x}Co{sub 4}O{sub 9−δ} (0 ≤ x ≤ 0.2) were obtained by a proteic sol-gel method which uses gelatin as polymerizing agent. As-prepared materials were calcined at 900 °C for 1 h and characterized by X-ray diffraction, with Rietveld refinement of the diffraction data, and scanning electron microscopy. Screen-printed porous electrodes fired (at 950 °C for 2 h) on both faces of ceria based electrolytes were electrochemically characterized by impedance spectroscopy between 600 and 800 °C in air atmosphere. The results indicated the attainment of Ca{sub 3−x}Cu{sub x}Co{sub 4}O{sub 9−δ} solid solutions with monoclinic misfit layered structure and around 2 vol% Co{sub 3}O{sub 4} as a secondary phase. Micro-plates like powders had irregular shape and average diameter near 2 μm. The area specific resistance (ASR) is in line with literature data for cathodes of similar compositions prepared by other synthetic routes. ASR was optimized for the composition Ca{sub 2.99}Cu{sub 0.01}Co{sub 4}O{sub 9−δ}, achieving 0.84 Ω cm{sup 2} at 800 °C in air. - Highlights: • Proteic sol-gel synthesis of Ca{sub 3−x}Cu{sub x}Co{sub 4}O{sub 9−δ} (0 ≤ x ≤ 0.2). • Cu{sup 2+} doping enhances electrode densification. • Area specific resistance (ASR = 0.84 Ω cm{sup 2} at 800 °C) optimized for Ca{sub 2.99}Cu{sub 0.01}Co{sub 4}O{sub 9−δ}.

  12. Chemical compatibility of alternative perovskite oxide SOFC cathodes with doped lanthanum gallate solid electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Kostogloudis, G.C.; Ftikos, C. [Laboratory of Inorganic Materials Technology, Department of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Str., Zografou Campus, GR-15780 Athens (Greece); Ahmad-Khanlou, A.; Naoumidis, A.; Stoever, D. [Research Centre Juelich, Institute for Materials and Processes in Energy Systems IWV1, D-52425 Juelich (Germany)

    2000-10-01

    This paper reports on the investigations of the chemical compatibility between SOFC cathode materials with compositions Pr{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Mn{sub 0.8}O{sub 3-{delta}}, Pr{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}}, Pr{sub 0.8}Sr{sub 0.2}Co{sub 0.3}Mn{sub 0.7}O{sub 3-{delta}} and Pr{sub 0.75}Sr{sub 0.2}Co{sub 0.2}Mn{sub 0.8}O{sub 3-{delta}} and the electrolyte materials with compositions La{sub 0.8}Sr{sub 0.2}Ga{sub 0.9}Mg{sub 0.1}O{sub 3-{delta}}, and La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{delta}}. The lanthanum gallate electrolyte with 20 mol.% Sr contained two additional phases, namely, LaSrGa{sub 3}O{sub 7} and LaSrGaO{sub 4}, while that with 10 mol.% Sr was formed in nearly single phase. Two types of experiments were performed: (a) reactivity experiments of powder mixtures and (b) diffusion experiments in cathode/electrolyte double-layer pellets. No reaction products were detected by XRD. High Co diffusion into the electrolyte was identified with SEM/EDX in all diffusion experiments examined. The transition metals diffuse in the order Mn

  13. High-fidelity stack and system modeling for tubular solid oxide fuel cell system design and thermal management

    Science.gov (United States)

    Kattke, K. J.; Braun, R. J.; Colclasure, A. M.; Goldin, G.

    Effective thermal integration of system components is critical to the performance of small-scale (design and simulation tool for a highly-integrated tubular SOFC system. The SOFC is modeled using a high fidelity, one-dimensional tube model coupled to a three-dimensional computational fluid dynamics (CFD) model. Recuperative heat exchange between SOFC tail-gas and inlet cathode air and reformer air/fuel preheat processes are captured within the CFD model. Quasi one-dimensional thermal resistance models of the tail-gas combustor (TGC) and catalytic partial oxidation (CPOx) complete the balance of plant (BoP) and SOFC coupling. The simulation tool is demonstrated on a prototype 66-tube SOFC system with 650 W of nominal gross power. Stack cooling predominately occurs at the external surface of the tubes where radiation accounts for 66-92% of heat transfer. A strong relationship develops between the power output of a tube and its view factor to the relatively cold cylinder wall surrounding the bundle. The bundle geometry yields seven view factor groupings which correspond to seven power groupings with tube powers ranging from 7.6-10.8 W. Furthermore, the low effectiveness of the co-flow recuperator contributes to lower tube powers at the bundle outer periphery.

  14. High performance ceria-bismuth bilayer electrolyte low temperature solid oxide fuel cells (LT-SOFCs) fabricated by combining co-pressing with drop-coating

    KAUST Repository

    Hou, Jie; Bi, Lei; Qian, Jing; Zhu, Zhiwen; Zhang, Junyu; Liu, Wei

    2015-01-01

    The Sm0.075Nd0.075Ce0.85O2-δ-Er0.4Bi1.6O3 bilayer structure film, which showed an encouraging performance in LT-SOFCs, was successfully fabricated by a simple low cost technique combining one-step co-pressing with drop-coating.

  15. High performance ceria-bismuth bilayer electrolyte low temperature solid oxide fuel cells (LT-SOFCs) fabricated by combining co-pressing with drop-coating

    KAUST Repository

    Hou, Jie

    2015-03-24

    The Sm0.075Nd0.075Ce0.85O2-δ-Er0.4Bi1.6O3 bilayer structure film, which showed an encouraging performance in LT-SOFCs, was successfully fabricated by a simple low cost technique combining one-step co-pressing with drop-coating.

  16. Direct Simulation of Transport Properties from Three-Dimensional (3D) Reconstructed Solid-Oxide Fuel-Cell (SOFC) Electrode Microstructures

    International Nuclear Information System (INIS)

    Gunda, Naga Siva Kumar; Mitra, Sushanta K

    2012-01-01

    A well-known approach to develop a high efficiency solid-oxide fuel-cell (SOFC) consists of extracting the microstructure and transport properties such as volume fractions, internal surface area, geometric connectivity, effective gas diffusivity, effective electronic conductivity and geometric tortuosities from three-dimensional (3D) microstructure of the SOFC electrodes; thereafter, performing the SOFC efficiency calculations using previously mentioned quantities. In the present work, dual-beam focused ion beam - scanning electron microscopy (FIB-SEM) is applied on one of the SOFC cathodes, a lanthanum strontium manganite (LSM) electrode, to estimate the aforementioned properties. A framework for calculating transport properties is presented in this work. 3D microstructures of LSM electrode are reconstructed from a series of two-dimensional (2D) cross-sectional FIB-SEM images. Volume percentages of connected, isolated and dead-ends networks of pore and LSM phases are estimated. Different networks of pore and LSM phases are discretized with tetrahedral elements. Finally, the finite element method (FEM) is applied to calculate effective gas diffusivity and electronic conductivity of pore and LSM phases, respectively. Geometric tortuosities are estimated from the porosity and effective transport properties. The results obtained using FEM are compared with the finite volume method (FVM) results obtained by Gunda et al. [J. Power Sources, 196(7), 35929(2011)] and other numerical results obtained on randomly generated porous medium. Effect of consideration of dead-ends and isolated-ends networks on calculation of effective transport properties is studied.

  17. Numerical model for evaluation of the effects of carbon deposition on the performance of 1 kW SOFC stack – a proposal

    Directory of Open Access Journals (Sweden)

    Motylinski Konrad

    2017-01-01

    Full Text Available Solid oxide fuel cells are high-temperature electrochemical energy conversion devices which operate at elevated temperature (600- 900°C. As a result it possible to internally reform the incoming fuel, thus except hydrogen and carbon monoxide, SOFCs can be fuelled with various hydrocarbonaceous gases. The presence of carbon-containing compounds in the fuel might result in the formation and of carbon in a form of a thin layer on the SOFC anode. The carbon deposition process depends on the thermodynamic conditions, such as temperature and steam to carbon ratio. The higher the temperature, the longer period of time is required for the solid carbon particles to deposit on the porous surface. The correlation used for this study is based on creating the ternary diagrams or Gibb’s diagrams. The presented results cover a first stage of the analysis of the carbon deposition processes in SOFCs, focusing mainly on the numerical study of the changes of the fuel cell performance due to degradation of anode performance. A dedicated model of SOFC was proposed. It accounts for the diminution of the active area and/or deactivation by the increase of the resistance of the anode. The article presents the proposed methodology and the numerical approach.

  18. Integration of solid oxide fuel cell (SOFC) and chemical looping combustion (CLC) for ultra-high efficiency power generation and CO2 production

    NARCIS (Netherlands)

    Spallina, Vincenzo; Nocerino, Pasquale; Romano, Matteo C.; van Sint Annaland, Martin; Campanari, Stefano; Gallucci, Fausto

    2018-01-01

    This work presents a thermodynamic analysis of the integration of solid oxide fuel cells (SOFCs) with chemical looping combustion (CLC) in natural gas power plants. The fundamental idea of the proposed process integration is to use a dual fluidized-bed CLC process to complete the oxidation of the

  19. Is it possible to design a portable power generator based on micro-solid oxide fuel cells? A finite volume analysis

    Science.gov (United States)

    Pla, D.; Sánchez-González, A.; Garbayo, I.; Salleras, M.; Morata, A.; Tarancón, A.

    2015-10-01

    The inherent limited capacity of current battery technology is not sufficient for covering the increasing power requirements of widely extended portable devices. Among other promising alternatives, recent advances in the field of micro-Solid Oxide Fuel Cells (μ-SOFCs) converted this disruptive technology into a serious candidate to power next generations of portable devices. However, the implementation of single cells in real devices, i.e. μ-SOFC stacks coupled to the required balance-of-plant elements like fuel reformers or post combustors, still remains unexplored. This work aims addressing this system-level research by proposing a new compact design of a vertically stacked device fuelled with ethanol. The feasibility and design optimization for achieving a thermally self-sustained regime and a rapid and low-power consuming start-up is studied by finite volume analysis. An optimal thermal insulation strategy is defined to maintain the steady-state operation temperature of the μ-SOFC at 973 K and an external temperature lower than 323 K. A hybrid start-up procedure, based on heaters embedded in the μ-SOFCs and heat released by chemical reactions in the post-combustion unit, is analyzed allowing start-up times below 1 min and energy consumption under 500 J. These results clearly demonstrate the feasibility of high temperature μ-SOFC power systems fuelled with hydrocarbons for portable applications, therefore, anticipating a new family of mobile and uninterrupted power generators.

  20. Structural design considerations for micromachined solid-oxide fuel cells

    Science.gov (United States)

    Srikar, V. T.; Turner, Kevin T.; Andrew Ie, Tze Yung; Spearing, S. Mark

    Micromachined solid-oxide fuel cells (μSOFCs) are among a class of devices being investigated for portable power generation. Optimization of the performance and reliability of such devices requires robust, scale-dependent, design methodologies. In this first analysis, we consider the structural design of planar, electrolyte-supported, μSOFCs from the viewpoints of electrochemical performance, mechanical stability and reliability, and thermal behavior. The effect of electrolyte thickness on fuel cell performance is evaluated using a simple analytical model. Design diagrams that account explicitly for thermal and intrinsic residual stresses are presented to identify geometries that are resistant to fracture and buckling. Analysis of energy loss due to in-plane heat conduction highlights the importance of efficient thermal isolation in microscale fuel cell design.

  1. Characterization of a well performing and durable Ni:CGO-infiltrated anode for metal-supported SOFC

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Klemensø, Trine; Graves, Christopher R.

    3000 hours of 0.25A/cm2 galvanostatic testing at 650 ºC was shown. Furthermore, it was shown on button cells that if the cathode side consisted of a dense CGO barrier layer in combination with a LSC cathode, a performance with an area specific resistance (ASR) of 0.27 Ω cm2 at 650 ºC could be obtained....... These performance and durability characteristics are very encouraging but despite several papers on metal supported SOFC with this type of infiltrated anode [1-3], the performance and the factors controlling the performance and durability is not yet well understood. Only some initial data on symmetrical cells...

  2. A chemically stable electrolyte with a novel sandwiched structure for proton-conducting solid oxide fuel cells (SOFCs)

    KAUST Repository

    Bi, Lei

    2013-11-01

    A chemically stable electrolyte structure was developed for proton-conducting SOFCs by using two layers of stable BaZr0.7Pr 0.1Y0.2O3 -δ to sandwich a highly-conductive but unstable BaCe0.8Y0.2O 3 -δ electrolyte layer. The sandwiched electrolyte structure showed good chemical stability in both CO2 and H2O atmosphere, indicating that the BZPY layers effectively protect the inner BCY electrolyte, while the BCY electrolyte alone decomposed completely under the same conditions. Fuel cell prototypes fabricated with the sandwiched electrolyte achieved a relatively high performance of 185 mW cm- 2 at 700 C, with a high electrolyte film conductivity of 4 × 10- 3 S cm- 1 at 600 C. © 2013 Elsevier B.V.

  3. Efficient modeling of metallic interconnects for thermo-mechanical simulation of SOFC stacks: homogenized behaviors and effect of contact

    DEFF Research Database (Denmark)

    Tadesse Molla, Tesfaye; Kwok, Kawai; Frandsen, Henrik Lund

    2016-01-01

    temperature, deformations involving the elastic, creep as well as effect of changes in the geometry due to contact should be accounted for. The constitutive law can be applied using 3D modeling, but for simple presentation of the theory, 2D plane strain formulation is used to model the corrugated metallic......Currently thermo-mechanical analysis of the entire solid oxide fuel cell (SOFC) stack at operational conditions is computationally challenging if the geometry of metallic interconnects is considered explicitly. This is particularly the case when creep deformations in the interconnect are considered...... model to calculate the homogenized mechanical response of corrugated metallic interconnects at high temperatures.Thereafter, a constitutive law for the homogenized structure (effective material law) is developed. In order to properly describe the mechanical behavior of the interconnect at high...

  4. R and D of proton conducting SOFC reactors to co-generate electricity and ethylene at University of Alberta

    International Nuclear Information System (INIS)

    Fu, X.Z.; Zhou, G.H.; Luo, J.L.; Chuang, K.T.; Sanger, A.R.

    2010-01-01

    Ethane exists in many natural gas deposits and is also a by-product of petroleum refining. Ethane's primary use is as a petrochemical feedstock to produce ethylene, a major intermediate in the manufacture of polymers and petrochemicals. Steam cracking is the principal method for conversion of ethane to ethylene. However, in this process, over 10 per cent of ethane is oxidized to carbon dioxide (CO 2 ), generating a nitrogen oxide pollutant. A large amount of ethane is deeply oxidized to CO 2 using common oxidative dehydrogenation of ethane to ethylene, and the chemical energy is not easily recovered as high grade energy. In addition, oxidative methods also produce acetylene, which is very detrimental to the manufacture of polymers because it poisons the catalysts and must therefore be removed to form high purity ethylene feed, which is a costly process. Ethane has the potential to be used as a fuel for hydrocarbon solid oxide fuel cells (SOFCs) to generate electrical energy with high efficiency and low impact on the environment, in which it is completely oxidized to CO 2 and water. However, consumption of ethane generates greenhouse gas (CO 2 ) emissions in conventional SOFCs using oxygen ion electrolyte, and consumption of these non-renewable resources is less desirable than their use for manufacture of petrochemicals. This paper discussed the development of ethane proton conducting solid oxide fuel cell reactors and related materials in order to more efficiently use ethane resources in an environmentally friendly process. The advantages of these fuel cell reactors were presented. 5 refs.

  5. Control of anode supported SOFCs (solid oxide fuel cells): Part I. mathematical modeling and state estimation within one cell

    International Nuclear Information System (INIS)

    Amedi, Hamid Reza; Bazooyar, Bahamin; Pishvaie, Mahmoud Reza

    2015-01-01

    In this paper, a 3-dimensional mathematical model for one cell of an anode-supported SOFC (solid oxide fuel cells) is presented. The model is derived from the partial differential equations representing the conservation laws of ionic and electronic charges, mass, energy, and momentum. The model is implemented to fully characterize the steady state operation of the cell with countercurrent flow pattern of fuel and air. The model is also used for the comparison of countercurrent with concurrent flow patterns in terms of thermal stress (temperature distribution) and quality of operation (current density). Results reveal that the steady-state cell performance curve and output of simulations qualitatively match experimental data of the literature. Results also demonstrate that countercurrent flow pattern leads to an even distribution of temperature, more uniform current density along the cell and thus is more enduring and superior to the concurrent flow pattern. Afterward, the thorough 3-dimensional model is used for state estimation instead of a real cell. To estimate states, the model is simplified and changed to a 1-dimensional model along flow streams. This simplified model includes uncertainty (because of simplifying assumptions of the model), noise, and disturbance (because of measurements). The behaviors of extended and ensemble Kalman filter as an observer are evaluated in terms of estimating the states and filtering the noises. Results demonstrate that, like extended Kalman filter, ensemble Kalman filter properly estimates the states with 20 sets. - Highlights: • A 3-dimensional model for one cell of SOFC (solid oxide fuel cells) is presented. • Higher voltages and thermal stress in countercurrent than concurrent flow pattern. • State estimation of the cell is examined by ensemble and extended Kalman filters. • Ensemble with 20 sets is as good as extended Kalman filter.

  6. Gd0.6Sr0.4Fe0.8Co0.2O3-δ: A novel type of SOFC cathode

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent; Søgaard, Martin; Mogensen, Mogens Bjerg

    2007-01-01

    The fabrication and electrochemical activity of a type of solid oxide fuel cell (SOFC) cathode is described in this paper. In search of new cathodes a Gd0.6Sr0.4Fe0.8Co0.2O3-delta compound was synthesized using the glycine-nitrate method. It turned out that this was a two-phase compound consisting...... of two perovskite phases, a cubic and an orthorhombic phase, as shown by Rietveld refinements. These two phases were synthesized and a cone-shaped electrode study was undertaken. It was shown that the composite cathode had an electrochemical activity superior to that of the two single-phase perovskites......, indicating that the unique microstructure of this type of cathode is essential for achieving high electrochemical activity toward the reduction of oxygen in a SOFC....

  7. A Novel SOFC/SOEC Sealing Glass with a Low SiO2 Content and a High Thermal Expansion Coefficient

    DEFF Research Database (Denmark)

    Kiebach, Wolff-Ragnar; Agersted, Karsten; Zielke, Philipp

    2017-01-01

    the amount of Si emission, a low Si containing sealing glass (chemical composition: 50 mol% CaO, 20 mol% ZnO, 20 mol% B2O3 and 10 mol% SiO2) was developed at DTU. In this work, the results from thermal characterization, the crystallization behavior of the glass and the long-term stability and adhesion......Solid oxide cells require seals that can function in harsh, elevated temperature environments. In addition, a low Si content can be advantageous, since Si impurities from the glass sealant can be transported to the active fuel electrode and poison the Ni-YSZ triple phase boundaries. To reduce...... behavior of the glass were studied under SOFC and SOEC relevant conditions. The glass-ceramic sealant performed well over 400 h, and no cell degradation or leakage related to the seal was found, indicating that the developed glass system is applicable for the use in SOFC/SOEC stacks....

  8. Fuel Cell Power Plant Initiative. Volume II: Preliminary Design of a Fixed-Base LFP/SOFC Power System

    National Research Council Canada - National Science Library

    Veyo, S

    1997-01-01

    .... Fuel cells are electrochemical devices that directly convert the chemical energy contained in fuels such as hydrogen, natural gas, or coal gas into electricity at high efficiency with no intermediate...

  9. Investigations of the oxidation-induced service life of chromium steels for high temperature fuel cell application (SOFC); Untersuchungen zur oxidationsbedingten Lebensdauer von Chromstaehlen fuer die Anwendung in der Hochtemperaturbrennstoffzelle (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Ertl, S.T.

    2006-08-17

    The increasing energy consumption of future automobiles should be covered by a solid oxide fuel cell (SOFC) used as an additional energy supply (auxiliary power unit). The application of a SOFC with about 5 kW power in cars requires small size, low weight and an economic fabrication. To achieve this goal the interconnector and the metallic anode substrate (depending on an alternative concept of construction) should be manufactured out of thin Crofer22APU, a high chromium ferritic steel. The scale formation mechanisms on Crofer22APU sheets, wires and powder metallurgical produced foils of different thicknesses were investigated in several atmospheres of water vapour/hydrogen at 800 and 900 C, simulating the anode conditions. For scale characterization a number of conventional analysis techniques such as optical metallography, scanning electron microscopy and X-ray diffraction were used in combination with deflection testing in monofacial oxidation and two-stage oxidation studies using {sup 18}O and H{sub 2} {sup 18}O tracer. With these results a theoretical model for the determination of lifetime was developed for Crofer22APU components in simulated anode gas. It was found that the lifetime at a given temperature depends not only on the surface-to-volume ratio, but also on the geometry of the component (e.g. sheet or wire). The critical Cr content required for breakaway oxidation depends on microcrack formation in the surface oxide scale, which occurs on ridges of a sheet during thermal cycling. The development of a metallic interconnector and a metallic anode substrate requires measures to avoid interdiffusion between the alloy and the bordering nickel-YSZ (yttrium stabilized zirconia) cermet of the anode, or depending on the conception of the stack, the bordering nickel-YSZ cermet of the anode functional layer. Therefore the suitability of preoxidation layers after different preoxidation conditions was tested. It was found that the inhibition of the interdiffusion

  10. Layered SmBaCuCoO5+δ and SmBaCuFeO5+δ perovskite oxides as cathode materials for proton-conducting SOFCs

    International Nuclear Information System (INIS)

    Nian Qiong; Zhao Ling; He Beibei; Lin Bin; Peng Ranran; Meng Guangyao; Liu Xingqin

    2010-01-01

    A dense BaCe 0.8 Sm 0.2 O 5+δ (BCS) electrolyte was fabricated on a porous anode by in situ drop-coating to develop a simple and cost-effective route to fabricate proton-conducting solid oxide fuel cells (SOFCs). Layered perovskite-structure oxides SmBaCuCoO 5+δ (SBCC) and SmBaCuFeO 5+δ (SBCF) were prepared and the electrical conductivity, the thermal expansion coefficient and electrochemical performance were investigated as potential cathode materials for proton-conducting SOFCs. Thermal expansion coefficients of SBCC and SBCF were suitable for BCS electrolyte and the electrical conductivity of the SBCC is higher than that of the SBCF. The maximum power density of 449 mW cm 2 and 333 mW cm 2 at 700 o C were obtained for the SBCC/BCS/NiO-BCS and SBCF/BCS/NiO-BCS cells, respectively. The interfacial polarization resistances for SBCC and SBCF cathode are as low as 0.137 Ω cm -2 and 0.196 Ω cm -2 at 700 o C, respectively. The results indicate that the SBCC and SBCF are promising cathode materials for proton-conducting SOFCs.

  11. Oxides with polyatomic anions considered as new electrolyte materials for solid oxide fuel cells (SOFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Bin Hassan, Oskar Hasdinor

    2010-10-21

    Materials with Polyatomic anions of [Al{sub 2}O{sub 7}]{sup -8}, [Ti{sub 2}O{sub 8}]{sup -8} and [P{sub 2}O{sub 7}]{sup -4} were investigated with respect to their ionic conductivity properties as well as its thermal expansion properties with the aim to use them as SOFCs electrolytes. The polyatomic anion groups selected from the oxy-cuspidine family of Gd{sub 4}Al{sub 2}O{sub 9} and Gd{sub 4}Ti{sub 2}O{sub 10} as well as from pyrophosphate SnP{sub 2}O{sub 7}. The pure oxy-cuspidine Gd{sub 4}Al{sub 2}O{sub 9}, the series of Gd{sub 4}Al{sub 2-x}Mg{sub x}O{sub 9-x/2} with x=0.10-1.0 and Gd{sub 4-x}M{sub x}Al{sub 2}O{sub 9-x/2} (M=Ca, Sr) with x = 0.05-0.5 were prepared successfully by the citrate complexation method. All samples showed the crystal structure of monoclinic oxycuspidine structure with space group of P2{sub 1/c} and Z=4. No solid solution was observed for Gd{sub 4}Al{sub 2-x}Mg{sub x}O{sub 9-x/2} where additional phases of Gd{sub 2}O{sub 3} and MgO were presence. XRD semiquantitative analysis together with SEM-EDX analysis revealed that Mg{sup 2+} was not able to substitute the Al{sup 3+} ions even at low Mg{sup 2+} concentration. The solid solution limit of Gd{sub 4-x}Ca{sub x}Al{sub 2}O{sub 9-x/2} and Gd{sub 4-x}Sr{sub x}Al{sub 2}O{sub 9-x/2} was determined between 0.05-0.10 and 0.01-0.05 mol for Ca and Sr, respectively. Beyond the substitution limit Gd{sub 4}Al{sub 2}O{sub 9}, GdAlO{sub 3} and SrGd{sub 2}Al{sub 2}O{sub 7} appeared as additional phases. The highest electrical conductivity obtained at 900 C yielded {sigma}= 1.49 x 10{sup -4}Scm{sup -1} for Gd{sub 3.95}Ca{sub 0.05}Al{sub 2}O{sub 8.98}. In comparison, the conductivity of pure Gd{sub 4}Al{sub 2}O{sub 9} was {sigma}= 1.73 x 10{sup -5} Scm{sup -1}. The conductivities determined were in a similar range as those of other cuspidine materials investigated previously. The thermal expansion coefficient of Gd{sub 4}Al{sub 2}O{sub 9} at 1000 C was 7.4 x 10{sup -6}K{sup -1}. The earlier reported

  12. Design

    DEFF Research Database (Denmark)

    Volf, Mette

    This publication is unique in its demystification and operationalization of the complex and elusive nature of the design process. The publication portrays the designer’s daily work and the creative process, which the designer is a part of. Apart from displaying the designer’s work methods...... and design parameters, the publication shows examples from renowned Danish design firms. Through these examples the reader gets an insight into the designer’s reality....

  13. Thermodynamical simulation for solid oxide (SOFC) type fuel cells with ethanol direct internal reforming; Simulacao termodinamica para celulas a combustivel do tipo SOFC com reforma interna direta do etanol

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Aline Lima da; Malfatti, Celia de Fraga; Heck, Nestor Cezar [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia de Minas, Metalurgica e de Materiais (PPGEM)]. E-mail: als14br2000@yahoo.com.br; Mello, Celso Gustavo [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Quimica (PPGEQ); Halmenschlager, Cibele Melo [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia de Minas, Metalurgica e de Materiais (PPGEM). Lab. de Materiais Ceramicos

    2008-07-01

    In SOFC, high operative temperature allows the direct conversion of ethanol into H{sub 2} to take place in the electrochemical cell. Direct internal reforming of ethanol, however, can produce undesirable products that diminish system efficiency and, in the case of carbon deposition over the anode, may occur the breakdown of the electrode. In this way, thermodynamic analysis is fundamental to predict the product distribution as well as the conditions favorable for carbon to precipitate inside the cell. Equilibrium determinations are performed by the Gibbs energy minimization method, using the GRG algorithm. Thermodynamic conditions for carbon deposition were analyzed, in order to establish temperature ranges and H{sub 2}O/ethanol ratios where carbon precipitation is not feasible. A mathematical relationship between Lagrange multipliers and carbon activity is presented, unveiling the carbon activity in atmosphere. The effect of the type of solid electrolyte (O{sup 2-} or H{sup +} conducting) on carbon formation is also investigated. The results of this work are in agreement with previous results reported in literature using the stoichiometric method. (author)

  14. Microstructural evolution of nanosized Ce0.8Gd0.2O1.9/Ni infiltrate in a Zr0.84Y0.16O1.92-Sr0.94Ti0.9Nb0.1O3-δ based SOFC anode under electrochemical evaluation

    DEFF Research Database (Denmark)

    Zhang, Wei; Kuhn, Luise Theil; Ramos, Tania

    are of paramount importance for performance and performance stability. Therefore an accurate understanding of the microstructure evolution during electrochemical operation will facilitate evaluating performances of SOFC anodes, and in turn optimize its design. Here we report a wealth of microstructural...... investigations of Ce0.8Gd0.2O1.9/Ni (hereafter CGO/Ni)-infiltrated Zr0.84Y0.16O1.92 composited Sr0.94Ti0.9Nb0.1O3-δ (STN94/8YSZ) anode in a symmetric cell design under a short electrochemical evaluation test (fingerprint test), applying electrochemical impedance spectroscopy (EIS) at mild 3% H2O/H2 and harsh 50...

  15. Development of electrical efficiency measurement techniques for 10 kW-class SOFC system: Part I. Measurement of electrical efficiency

    International Nuclear Information System (INIS)

    Tanaka, Yohei; Momma, Akihiko; Kato, Ken; Negishi, Akira; Takano, Kiyonami; Nozaki, Ken; Kato, Tohru

    2009-01-01

    Measurement techniques to estimate electrical efficiency of 10 kW-class SOFC systems fueled by town-gas were developed and demonstrated for a system developed by Kansai Electric Power Company and Mitsubishi Materials Corporation under a NEDO project. Higher heating value of the fuel was evaluated with a transportable gas sampling unit and conventional gas chromatography in AIST laboratory with thermal-conductivity and flame-ionization detectors, leading to mean value 44.69 MJ m -3 on a volumetric base for ideal-gas at the standard state (0 deg. C, 101.325 kPa). Mass-flow-rate of the fuel was estimated as 33.04 slm with a mass-flow meter for CH 4 , which was calibrated to correct CH 4 flow-rate and effect of sensitivity change and to obtain conversion factor from CH 4 to town-gas. Without calibration, systematic effect would occur by 8% in flow-rate measurement in the case for CH 4 . Power output was measured with a precision power analyzer, a virtual three phase starpoint adapter, and tri-axial shunts. Power of fundamental wave (60 Hz) was estimated as 10.14 kW, considering from total active power, total higher harmonic distortion factor, and power consumption at the starpoint adapter. The electrical efficiency was presumed to be 41.2% (HHV), though this mean value will be complete only when uncertainty estimation is accompanied

  16. Recovery Act: Demonstration of a SOFC Generator Fueled by Propane to Provide Electrical Power to Real World Applications

    Energy Technology Data Exchange (ETDEWEB)

    Bessette, Norman [Acumentrics Corporation, Westwood, MA (United States)

    2016-08-01

    The objective of this project provided with funds through the American Recovery and Reinvestment Act of 2009 (ARRA) was to demonstrate a Solid Oxide Fuel Cell (SOFC) generator capable of operation on propane fuel to improve efficiency and reduce emissions over commercially available portable generators. The key objectives can be summarized as: Development of two portable electrical generators in the 1-3kW range utilizing Solid Oxide Fuel Cells and propane fuel; The development and demonstration of a proof-of-concept electro-mechanical propane fuel interface that provides a user friendly capability for managing propane fuel; The deployment and use of the fuel cell portable generators to power media production equipment over the course of several months at multiple NASCAR automobile racing events; The deployment and use of the fuel cell portable generators at scheduled events by first responders (police, fire) of the City of Folsom California; and Capturing data with regard to the systems’ ability to meet Department of Energy (DOE) Technical Targets and evaluating the ease of use and potential barriers to further adoption of the systems.

  17. Microstructural characterization of Ni/YSZ based SOFC anodes after cyclic reduction and oxidation using electron microscopy

    International Nuclear Information System (INIS)

    Waldbillig, D.; He, A.; Ivey, D.

    2003-01-01

    The effect of redox cycling on the microstructure, of an SOFC anode, was studied using two approaches. Bulk samples were redox cycled and then examined in the SEM. In addition, electron transparent samples were prepared, redox cycled, and then examined in the TEM. Significant microstructural changes were observed. The anode in the as received condition consists of NiO particles several microns in size, YSZ grains about one micron in size and intergranular porosity. After the first reduction, the overall Ni grain size remains the same as the consumed NiO and epitaxial growth of Ni crystals on NiO grains is observed. The amount of intergranular porosity increases and very fine (50 nm) intragranular pores are formed throughout the Ni grains. This increase in the amount of porosity is expected due to the large volume change that occurs upon reduction. When samples are reoxidized the NiO particles in the SEM images appear spongy with much smaller pores than the as received, oxidized samples. The reoxidized anode consists of fine (<100 nm), randomly oriented grains of NiO. The grain refinement that occurs upon reoxidation is likely due to the large number of intragranular pores that occur upon reduction, which serve as nucleation sites. Rereduced samples were also very fine grained (<200 nm) and contained significant amounts of small intergranular porosity. The YSZ grains were unaffected by the redox cycles. (author)

  18. MnCo{sub 2}O{sub 4} spinel chromium barrier coatings for SOFC interconnect by HVOF

    Energy Technology Data Exchange (ETDEWEB)

    Lagerbom, J.; Varis, T.; Pihlatie, M.; Himanen, O.; Saarinen, V.; Kiviaho, J.; Turunen, E. [VTT Technical Research Centre of Finland, Espoo (Finland); Puranen, J. [Tampere Univ. of Technology (Finland). Inst. of Materials Science

    2010-07-01

    Chromia released from steel parts used for interconnect plates by evaporation and condensation can quickly degrade the cell (cathode) performance in solid oxide fuel cell SOFC. Coatings on top of the IC plate can work as a chromium evaporation barrier. The coating material should have good electrical conductivity, high temperature stability and nearly the same coefficient of thermal expansion as the cell materials. One candidate for the coating material is MnCo{sub 2}O{sub 4} spinel because of its suitable properties. High velocity oxy fuel (HVOF) spraying was used for the coating application on Crofer 22 APU steel samples. Using commercial and self made spray dried powders together with an HV2000 spray gun it was possible to successfully manufacture, well adhering, dense and reasonably uniform coatings. The samples were tested in oxidation exposure tests in air followed by post analysis in SEM. Powders and coatings microstructures are presented here, both before and after exposure. It was found out that together with spraying parameters the powder characteristics used influence clearly to the coating quality. Especially as very thin coatings was aimed with dense structure fine powders was found to be essential. (orig.)

  19. High Efficiency Power Converter for a Doubly-fed SOEC/SOFC System

    DEFF Research Database (Denmark)

    Tomas Manez, Kevin; Anthon, Alexander; Zhang, Zhe

    2016-01-01

    Regenerative fuel cells (RFC) have become an attractive technology for energy storage systems due to their high energy density and lower end-of-life disposal concerns. However, high efficiency design of power conditioning unit (PCU) for RFC becomes challenging due to their asymmetrical currentpow...... operating range of the RFC as well as the utilization of the same control strategy design for the two RFC operating modes....

  20. Design of a thermally integrated bioethanol-fueled solid oxide fuel cell system integrated with a distillation column

    Science.gov (United States)

    Jamsak, W.; Douglas, P. L.; Croiset, E.; Suwanwarangkul, R.; Laosiripojana, N.; Charojrochkul, S.; Assabumrungrat, S.

    Solid oxide fuel cell systems integrated with a distillation column (SOFC-DIS) have been investigated in this study. The MER (maximum energy recovery) network for SOFC-DIS system under the base conditions (C EtOH = 25%, EtOH recovery = 80%, V = 0.7 V, fuel utilization = 80%, T SOFC = 1200 K) yields Q Cmin = 73.4 and Q Hmin = 0 kW. To enhance the performance of SOFC-DIS, utilization of internal useful heat sources from within the system (e.g. condenser duty and hot water from the bottom of the distillation column) and a cathode recirculation have been considered in this study. The utilization of condenser duty for preheating the incoming bioethanol and cathode recirculation for SOFC-DIS system were chosen and implemented to the SOFC-DIS (CondBio-CathRec). Different MER designs were investigated. The obtained MER network of CondBio-CathRec configuration shows the lower minimum cold utility (Q Cmin) of 55.9 kW and total cost index than that of the base case. A heat exchanger loop and utility path were also investigated. It was found that eliminate the high temperature distillate heat exchanger can lower the total cost index. The recommended network is that the hot effluent gas is heat exchanged with the anode heat exchanger, the external reformer, the air heat exchanger, the distillate heat exchanger and the reboiler, respectively. The corresponding performances of this design are 40.8%, 54.3%, 0.221 W cm -2 for overall electrical efficiency, Combine Heat and Power (CHP) efficiency and power density, respectively. The effect of operating conditions on composite curves on the design of heat exchanger network was investigated. The obtained composite curves can be divided into two groups: the threshold case and the pinch case. It was found that the pinch case which T SOFC = 1173 K yields higher total cost index than the CondBio-CathRec at the base conditions. It was also found that the pinch case can become a threshold case by adjusting split fraction or operating at

  1. Optimal design and operation of solid oxide fuel cell systems for small-scale stationary applications

    Science.gov (United States)

    Braun, Robert Joseph

    The advent of maturing fuel cell technologies presents an opportunity to achieve significant improvements in energy conversion efficiencies at many scales; thereby, simultaneously extending our finite resources and reducing "harmful" energy-related emissions to levels well below that of near-future regulatory standards. However, before realization of the advantages of fuel cells can take place, systems-level design issues regarding their application must be addressed. Using modeling and simulation, the present work offers optimal system design and operation strategies for stationary solid oxide fuel cell systems applied to single-family detached dwellings. A one-dimensional, steady-state finite-difference model of a solid oxide fuel cell (SOFC) is generated and verified against other mathematical SOFC models in the literature. Fuel cell system balance-of-plant components and costs are also modeled and used to provide an estimate of system capital and life cycle costs. The models are used to evaluate optimal cell-stack power output, the impact of cell operating and design parameters, fuel type, thermal energy recovery, system process design, and operating strategy on overall system energetic and economic performance. Optimal cell design voltage, fuel utilization, and operating temperature parameters are found using minimization of the life cycle costs. System design evaluations reveal that hydrogen-fueled SOFC systems demonstrate lower system efficiencies than methane-fueled systems. The use of recycled cell exhaust gases in process design in the stack periphery are found to produce the highest system electric and cogeneration efficiencies while achieving the lowest capital costs. Annual simulations reveal that efficiencies of 45% electric (LHV basis), 85% cogenerative, and simple economic paybacks of 5--8 years are feasible for 1--2 kW SOFC systems in residential-scale applications. Design guidelines that offer additional suggestions related to fuel cell

  2. Design

    DEFF Research Database (Denmark)

    Volf, Mette

    Design - proces & metode iBog®  er enestående i sit fokus på afmystificering og operationalisering af designprocessens flygtige og komplekse karakter. Udgivelsen går bag om designerens daglige arbejde og giver et indblik i den kreative skabelsesproces, som designeren er en del af. Udover et bredt...... indblik i designerens arbejdsmetoder og designparametre giver Design - proces & metode en række eksempler fra anerkendte designvirksomheder, der gør det muligt at komme helt tæt på designerens virkelighed....

  3. Design

    Science.gov (United States)

    Buchanan, Richard; Cross, Nigel; Durling, David; Nelson, Harold; Owen, Charles; Valtonen, Anna; Boling, Elizabeth; Gibbons, Andrew; Visscher-Voerman, Irene

    2013-01-01

    Scholars representing the field of design were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Richard Buchanan, Nigel Cross, David Durling, Harold Nelson, Charles Owen, and Anna Valtonen. Scholars…

  4. Electrochemical Characterization of Ni/ScYSZ Electrodes as SOFC Anodes

    DEFF Research Database (Denmark)

    Ramos, Tania; Søgaard, Martin; Mogensen, Mogens Bjerg

    2014-01-01

    Investigations of Ni/ScYSZ cermets were performed by electrochemical impedance spectroscopy (EIS) using different symmetric designs: electrolyte supported (ESC) and anode supported (ASC) cells. The obtained spectra were analyzed using distribution of relaxation times (DRT), and complex non......-linear least squares fitting (CNLS). Depending on the cell design, one or two low frequency gas transport related processes have been identified, and fitted with generalized finite Warburg (GFW) elements. One was related to gas diffusion in a stagnant layer above the anode (ESC+ASC), and the other to gas...... diffusion in the anode support layer (ASC). A higher frequency process has also been identified, and correlated to the charge transfer (CT) combined with ionic conduction in the ceramic matrix. This has been fitted using a transmission line model (TML), which correlates the exhibited responses...

  5. Investigation of Degradation Mechanisms of LSCF Based SOFC Cathodes — by CALPHAD Modeling and Experiments

    DEFF Research Database (Denmark)

    Zhang, Weiwei; Barfod, Rasmus

    cathodes, investigation of the La-Sr-Co-Fe-O system using computational thermodynamics and designed key experiments was carried out in this work. The first part of the research work was devoted to establish a self-consistent thermodynamic database of relevant components (La-Sr-Co-Fe-O) using the CALPHAD...... (CALculation of PHAse Diagrams) approach. Published thermodynamic databases and experimental data related to the La-Sr-Co-Fe-O system were critically reviewed. The thermodynamic descriptions of the La-Co-O, Sr-Co-O and La-Sr-Co-O systems were further improved in order to construct the present thermodynamic...... database for LSCF, while new thermodynamic modeling of the Co-Fe-O, Sr-Co-Fe-O and La-Sr-Co-Fe-O systems was performed in this work. Calculated phase equilibria in LSCF as functions of composition, temperature, oxygen partial pressure are discussed by comparing with experimental data. Based...

  6. Design optimisation of a hybrid solid oxide fuel cell and gas turbine power generation system

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G.J.; Siddle, A.; Pointon, K.

    2001-07-01

    The objectives of the combined ALSTOM Power Technology and Advantica Technologies project are reported as: (a) to design a gas turbine (GT) unit compatible with a solid oxide fuel cell (SOFC) in a high efficiency power system and aimed at the Distributed Power application range of 1-20MW, and (b) to identify the main features and components of a 'Proof of Concept' hybrid unit of output around 0.1MW, based on existing or near-market technology. The study showed: (i) while the potential for high efficiency SOFC + GT hybrid cycles is clear, little effort has been put into the design of the gas turbine and some other components and (ii) there is room for commercial exploitation in the areas of both component manufacture and system supply.

  7. Design

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Pettiway, Keon

    2017-01-01

    In this chapter, Ole B. Jensen takes a situational approach to mobilities to examine how ordinary life activities are structured by technology and design. Using “staging mobilities” as a theoretical approach, Jensen considers mobilities as overlapping, actions, interactions and decisions by desig...... by providing ideas about future research for investigating mobilities in situ as a kind of “staging,” which he notes is influenced by the “material turn” in social sciences....... with a brief description of how movement is studied within social sciences after the “mobilities turn” versus the idea of physical movement in transport geography and engineering. He then explains how “mobilities design” was derived from connections between traffic and architecture. Jensen concludes...

  8. Synthesis and characterization of a novel Gd0.9Ba0.1CoO3-δ SOFC cathode material

    International Nuclear Information System (INIS)

    Lenka, R.K.; Mahata, T.; Sinha, P.K.; Tyagi, A.K.

    2012-01-01

    Perovskite materials with general formula ABO 3 (A = La and other rare earth metals, Ca, Sr, Ba etc.; B = Mn, Fe, Co, Ni etc.) are widely used as cathode materials in SOFCs. Doped cobaltites are reported to have better electro-catalytic activities for oxygen reduction reaction as well as higher electronic conductivities than other electrode materials. However, thermal expansion coefficient values of many cobaltites are significantly higher than that of commonly used oxygen ion conducting electrolyte materials. Among the different rare earth metals that form lanthanide cobaltite perovskites the thermal expansion coefficients (TEC) of the cobaltites decrease in the order of La, Pr, Nd, Sm and Gd. TEC can be tailored by substituting 'A' sites or Co sites with suitable elements. In general, substitution of Co site decreases catalytic activity and electronic conductivity. Increase in ionic conductivity has been reported with substitution in the 'A' site. In the present investigation 10 mol% Ba substituted GdCoO 3 has been studied as a SOFC cathode material

  9. Enhancing the lifetime of SOFC stacks for combined heat and power applications. SOF-CH. Final Report EPFL-LENI 2007: WP 5.1: Thermomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Nakajo, A.

    2008-07-01

    The solid oxide fuel cell (SOFC) is a direct conversion process, which allows the production of electricity with high efficiency while maintaining pollutant emissions at low level. This technology is now far beyond the theoretical status, but extensive commercialization is not yet attractive. The main challenges to face are cost reduction, lifetime, reliability and volumetric power densities. Typical issues are the degradation rate of the performance during steady operation and the risk of failure during controlled or emergency shut-ups/start-ups. Post mortem analysis shows that the mechanical integrity of the cells is often not ensured. Modelling of the thermo-electro-chemical behaviour of an intact or partially damaged SOFC stack is required to predict and reduce the degradation. The influence of small-scale defects and microstructural changes increases with respect to time and the number of thermal and loading cycles. A multiscale approach is suited to understand and characterize the phenomena at the membrane electrode assembly (MEA) level and study their impact and propagation at the repeat element (RE) level. Once critical conditions are identified, a control strategy is required to ensure the safe operation of an aging stack during both steady and transient operation. (author)

  10. Interfacial interactions between some La-based perovskite thick films and ferritic steel substrate with regard to the operating conditions of SOFC

    International Nuclear Information System (INIS)

    Przybylski, K.; Brylewski, T.; Morgiel, J.

    2004-01-01

    An overview is presented on the oxidation kinetics, electrical properties and microstructure investigations of the oxide products formed on Fe-25 wt.-%Cr steel uncoated and coated with electrical conducting films of (La,Ca)CrO 3 or (La,Sr)CoO 3 in air and H 2 /H 2 O gas mixture at 1023-1173 K for up to 480 hrs with regard to their application as the SOFC metallic interconnect. The application of the Fe-25Cr steel in SOFC operating at 1073 K requires its surface modification to improve the electrical conductivity of chromia scale forming on the uncoated steel surface. The thick films of (La,Ca)CrO 3 and (La,Sr)CoO 3 with the thickness range of 20-100 μm, coated on the Fe-25Cr steel by screen-printing method helped solve this problem. TEM-SAD, SEM-EDS and impedance spectroscopy investigations have shown significant influence of the multilayer products formation at the substrate steel/coating films interfacial zone on the electrical properties of the metallic interconnect. (orig.)

  11. SOFC - Manufacture of stacks for test and demonstration related activities, stack and system tests and identification of end user requirements. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, Joachim; Primdahl, S.; Boegh Elmose, H.; Weineisen, H.; Richter, A.

    2008-11-15

    The aim of the project was to solve the technical challenges in relation to stack functionality in connection with operation of multi stack assemblies under realistic operating conditions. It was the intention to make a targeted effort with the aim of developing a high performance stack technology suitable for both small and large units. An important part of the project was the testing of stack assemblies up to 10 kW power range with relevant fuel and realistic operation condition in the test facility at HC OErstedvaerket. The manufacturing of stacks in the project was as planned a number of stacks (70 kW) for use in demonstration projects both for single stacks and for multi stack assemblies. The start up of the work on the SOFC test facility at HC OErstedsvaerket (HCV) was delayed due to a late delivery of the unit from the PSO 6385 project. A number of unforeseen events during the project have meant that the SOFC test facility at HCV has not until now been ready for performing tests. The experience gained from the operation of a 20 kW Alpha unit in a co-operation between TOFC and Waertsilae now provides an important contribution to the future multi stack assemblies. The work on identification of end user requirements has resulted in a number of different development priorities for the m-CHP and the Distributed Generation market segments. (au)

  12. Control of Co content and SOFC cathode performance in Y1-ySr2+yCu3-xCoxO7+δ

    Science.gov (United States)

    Šimo, F.; Payne, J. L.; Demont, A.; Sayers, R.; Li, Ming; Collins, C. M.; Pitcher, M. J.; Claridge, J. B.; Rosseinsky, M. J.

    2014-11-01

    The electrochemical performance of the layered perovskite YSr2Cu3-xCoxO7+δ, a potential solid oxide fuel cell (SOFC) cathode, is improved by increasing the Co content from x = 1.00 to a maximum of x = 1.30. Single phase samples with x > 1.00 are obtained by tuning the Y/Sr ratio, yielding the composition Y1-ySr2+yCu3-xCoxO7+δ (where y ≤ 0.05). The high temperature structure of Y0.95Sr2.05Cu1.7Co1.3O7+δ at 740 °C is characterised by powder neutron diffraction and the potential of this Co-enriched material as a SOFC cathode is investigated by combining AC impedance spectroscopy, four-probe DC conductivity and powder XRD measurements to determine its electrochemical properties along with its thermal stability and compatibility with a range of commercially available electrolytes. The material is shown to be compatible with doped ceria electrolytes at 900 °C.

  13. Microstructure control of SOFC cathode material: The role of dispersing agent

    Science.gov (United States)

    Ismail, Ismariza; Jani, Abdul Mutalib Md; Osman, Nafisah

    2017-09-01

    In the present works, La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode powders were synthesized by a sol-gel method with the aid of ethylene glycol which served as the dispersing agent. The phase formation and morphology of the powders were examined by X-Ray diffractometer (XRD) and field emission scanning electron microscopy (FESEM), respectively. The electrochemical properties of the synthesized cathode were obtained using an electrochemical impedance spectroscopy (EIS). The characteristic peaks for LSCF phase appears in the X-ray diffractogram after calcined at 500 °C and complete formation of LSCF single phase was attained at 700 °C. FESEM micrographs showed the presence of spherical particles of the powders with approximate particle size between 10 to 60 nm along with agglomerate morphologies. Well dispersed particles and fewer aggregates were observed for samples prepared with addition of ethylene glycol as the synthesizing aid. The surface area obtained for powder sample prepared with the aid of dispersing agent is 12.0 m2g-1. The EIS measurement results depicts a lower area specific resistance (ASR) obtained for sample prepared with addition of the ethylene glycol as compared to the pristine sample. The present results encourage the optimization of the cathode particle design in order to further improve the cathode performance.

  14. Electrochemical behaviour of (La1-xSrx)(s)Co1-yNiyO3-δ as porous SOFC cathodes

    DEFF Research Database (Denmark)

    Hjalmarsson, Per; Søgaard, Martin; Mogensen, Mogens Bjerg

    2009-01-01

    behaviours exhibited similar patterns with respect to the dependence on T and PO2. An increase in polarisation resistance with time at SOFC operating conditions was observed, which was related exclusively to the electrode reaction kinetics and not to oxygen concentration polarisation. It was also found...

  15. Design and development of major balance of plant components in solid oxide fuel cell system

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Wen-Tang; Huang, Cheng-Nan; Tan, Hsueh-I; Chao, Yu [Institute of Nuclear Energy Research Atomic Energy Council, Taoyuan County 32546 (Taiwan, Province of China); Yen, Tzu-Hsiang [Green Technology Research Institute, CPC Corporation, Chia-Yi City 60036 (Taiwan, Province of China)

    2013-07-01

    The balance of plant (BOP) of a Solid Oxide Fuel Cell (SOFC) system with a 2 kW stack and an electric efficiency of 40% is optimized using commercial GCTool software. The simulation results provide a detailed understanding of the optimal operating temperature, pressure and mass flow rate in all of the major BOP components, i.e., the gas distributor, the afterburner, the reformer and the heat exchanger. A series of experimental trials are performed to validate the simulation results. Overall, the results presented in this study not only indicate an appropriate set of operating conditions for the SOFC power system, but also suggest potential design improvements for several of the BOP components.

  16. Fuel cell: new electrocatalysts for SOFC (Solid Oxide Fuel Cells) anodes and regulation between cell performance and catalytic activity; Celula a combustivel: novos eletrocatalisadores para anodos de SOFC (Celulas a Combustivel de Oxido Solido) e correlacao entre desempenho da celula e atividade catalitica

    Energy Technology Data Exchange (ETDEWEB)

    Boaventura, Jaime S.; Aguiar, Aurinete B.; Brandao, Soraia T. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Frank, Maria Helena Troise; Campos, Michel F. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    Electro-catalysts were prepared using new routes. Chemical Ultrasound Deposition (CUD) method: aqueous solution of nickel nitrate and citric acid was ultrasound vaporized and deposited on heated Ytria-stabilized Zirconia (YSZ). Resin impregnation (IPR) method: nickel oxide and YSZ were mixed, added to phenolic resins, precipitated in acidic water and milled. Wet impregnation method (IMP) was used for comparison: YSZ and an aqueous solution of nickel nitrate and citric acid were mixed, followed by evaporation, drying and calcination. The catalysts were evaluated for methane steam reforming in a quartz reactor. The reactions were conducted for one hour with no significant catalytic activity loss. In reactions with 100 mg of catalyst and a mixture consisting of methane and steam (3:1), IPR catalyst showed activity higher and better stability than those by IMP. On other tests, the reform was conducted with 100 mg of catalyst and methane to steam of 10. The IPR catalyst activity was so high that the reaction approached equilibrium conditions. Anode/electrolyte/cathode units (A/E/C) were prepared with the above catalysts as follows: the anode was a catalyst porous layer; the electrolyte an YSZ dense layer; and the cathode an LSM porous layer; graphite powder formed the material porosity. The two first layers, in powder form, were put in a stainless steel cast, pressed to 4000 bars and sinterized. The cathode layer was subsequently added using tape-casting techniques followed by sintering. A/E/C units showed 40% linear contraction and porosity higher than 20%. For fuel cell tests, A/E/C was mounted in alumina plates with platinum current collectors. Unitary SOF cells were loaded with hydrogen diluted in nitrogen showing opened circuit voltage from circa 700 mV, for the CUD anode, to 350 mV, for the IPR anode. The unitary SOFC was loaded with methane for 15 minutes or longer, with no noticeable voltage loss. At 1300 K the SOFC made with IPR or IMP catalysts showed opened

  17. Rational Design of a Water-Storable Hierarchical Architecture Decorated with Amorphous Barium Oxide and Nickel Nanoparticles as a Solid Oxide Fuel Cell Anode with Excellent Sulfur Tolerance.

    Science.gov (United States)

    Song, Yufei; Wang, Wei; Ge, Lei; Xu, Xiaomin; Zhang, Zhenbao; Julião, Paulo Sérgio Barros; Zhou, Wei; Shao, Zongping

    2017-11-01

    Solid oxide fuel cells (SOFCs), which can directly convert chemical energy stored in fuels into electric power, represent a useful technology for a more sustainable future. They are particularly attractive given that they can be easily integrated into the currently available fossil fuel infrastructure to realize an ideal clean energy system. However, the widespread use of the SOFC technology is hindered by sulfur poisoning at the anode caused by the sulfur impurities in fossil fuels. Therefore, improving the sulfur tolerance of the anode is critical for developing SOFCs for use with fossil fuels. Herein, a novel, highly active, sulfur-tolerant anode for intermediate-temperature SOFCs is prepared via a facile impregnation and limited reaction protocol. During synthesis, Ni nanoparticles, water-storable BaZr 0.4 Ce 0.4 Y 0.2 O 3- δ (BZCY) perovskite, and amorphous BaO are formed in situ and deposited on the surface of a Sm 0.2 Ce 0.8 O 1.9 (SDC) scaffold. More specifically, a porous SDC scaffold is impregnated with a well-designed proton-conducting perovskite oxide liquid precursor with the nominal composition of Ba(Zr 0.4 Ce 0.4 Y 0.2 ) 0.8 Ni 0.2 O 3- δ (BZCYN), calcined and reduced in hydrogen. The as-synthesized hierarchical architecture exhibits high H 2 electro-oxidation activity, excellent operational stability, superior sulfur tolerance, and good thermal cyclability. This work demonstrates the potential of combining nanocatalysts and water-storable materials in advanced electrocatalysts for SOFCs.

  18. On the stability of Sr-doped La{sub 2}CuO{sub 4} against different electrolytes for IT-SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Bustos, R.; Santos-Garcia, A.J. dos; Sanchez-Bautista, C. [Instituto de Energias Renovables, Parque Cientifico y Tecnologico de Albacete, Paseo de la Investigacion 1, 02006 Albacete (Spain); Cantos-Gomez, A.; Duijn, J. van [Instituto de Energias Renovables, Universidad de Castilla La Mancha, Paseo de la Investigacion 1, 02006 Albacete (Spain)

    2011-02-15

    The thermal stability of the cathode material against an electrolyte at the operating temperature plays an important role in the fuel cell's performance. As such, compatibility tests of the most common used electrolytes with La{sub 2-x}Sr{sub x}CuO{sub 4} have been performed. The chemical reaction between these two materials in the temperature ranging from 800 to 1,000 C was examined by X-ray diffraction analyses. The results show that in all the cases there is reaction above 925 C, making conventional cell fabrication non-appropriate. However, we demonstrate that infiltration is a useful technique for obtaining cuprate cermets for use as cathode materials in IT-SOFCs. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. On the Predictions of Carbon Deposition on the Nickel Anode of a SOFC and Its Impact on Open-Circuit Conditions

    KAUST Repository

    Lee, W. Y.

    2012-12-04

    Previous thermodynamic analyses of carbon formation in SOFCs assumed that graphite could be used to represent the properties of carbon formed in the anode. It is generally observed, however, that catalytically grown carbon nanofibers (CNF) are more likely to form in the SOFC anode with nickel catalysts. The energetic and entropic properties of CNF are different from those of graphite.We compare equilibrium results based on thermochemical properties for graphite, to new results based on a previously reported value of an empirically determined Gibbs free energy for carbon fibers grown on a nickel support (with fitted values of H°CNF = 54.46 kJ/mol and S°CNF = 68.90 J/mol/K for a nickel crystal size of 5.4 nm). There is little difference in predictions of carbon formation under open-circuit conditions between the two carbon types for methane mixtures, with graphite predicted to form at lower temperatures than CNF. There is a much bigger difference in predictions for methanol mixtures, especially at low steam-carbon ratios. The differences for propane are even more pronounced, and the improved predictions assuming CNF are in closer agreement with past observations.We show a strong dependence of CNF formation and "coking threshold" on nickel crystallite size, supporting previous reports that the nickel particle size is a dominating parameter for controlling filament growth. If both carbon types are included in the calculations, only the thermodynamically favored form (i.e., the type having the lowest formation energy) exists. Predicted Nernst potentials are more-or-less independent of the carbon type and in agreement with measured open-circuit voltages. © 2012 The Electrochemical Society.

  20. In situ formation of a 3D core-shell and triple-conducting oxygen reduction reaction electrode for proton-conducting SOFCs

    Science.gov (United States)

    Zhang, Zhenbao; Wang, Jian; Chen, Yubo; Tan, Shaozao; Shao, Zongping; Chen, Dengjie

    2018-05-01

    BaZrxCeyY1-x-yO3-δ are recognized proton-conducting electrolyte materials for proton-conducting solid oxide fuel cells (H+-SOFCs) below 650 °C. Here Co cations are incorporated into the BaZr0.4Ce0.4Y0.2O3-δ (BZCY) scaffold to generate a 3D core-shell and triple-conducting (H+/O2-/e-) electrode in situ via infiltrating and reactive sintering. The core is the bulk BZCY scaffold, while the shell is composed of the cubic Ba(Zr0.4Ce0.4Y0.2)1-xCoxO3-δ, cubic spinel Co3O4 and cubic fluorite (Ce, Zr, Y)O2. The obtained electrode exhibits an excellent compatibility with the BZCY electrolyte, and performs well in yielding a low and stable polarization resistance for oxygen reduction reaction for intermediate-temperature H+-SOFCs. In particular, it achieves polarization resistances as low as 0.094 and 0.198 Ω cm2 at 650 and 600 °C in wet air (3% H2O) when the sintering temperature for the electrode is 900 °C. In addition, a symmetrical cell also exhibits operation stability of 70 h at 650 °C. Furthermore, a fuel cell assembled with the 3D core-shell and triple-conducting electrode delivers a peak power density of ∼330 mW cm-2 at 650 °C. The substantially improved electrochemical performance and high stability are ascribed to the unique core-shell structure and the formation of Ba(Zr0.4Ce0.4Y0.2)1-xCoxO3-δ in the shell.

  1. Electrochemical characterization of La0.6Ca0.4Fe0.8Ni0.2O3 cathode on Ce0.8Gd0.2O1.9 electrolyte for IT-SOFC

    DEFF Research Database (Denmark)

    Ortiz-Vitoriano, N.; Bernuy-Lopez, C.; Hauch, Anne

    2014-01-01

    For Solid Oxide Fuel Cells (SOFCs) to become an economically attractive energy conversion technology, suitable materials and structures which enable operation at lower temperatures, while retaining high cell performance, must be developed. Recently, the perovskitetype La0.6Ca0.4Fe0.8Ni0.2O3 oxide...... has shown potential as an intermediate temperature SOFC cathode. An equivalent circuit describing the cathode polarization resistances was constructed from analyzing impedance spectra recorded at different temperatures in oxygen. A competitive electrode polarization resistance is reported...... for this oxygen electrode using a Ce0.8Gd0.2O1.9 electrolyte, determined by impedance spectroscopy studies of symmetrical cells sintered at 800 _C and 1000 _C. Scanning electron microscopy (SEM) studies of the symmetrical cells revealed the absence of any reaction layer between cathode and electrolyte...

  2. Effects of Pr-deficiency on thermal expansion and electrochemical properties in Pr_1_−_xBaCo_2O_5_+_δ cathodes for IT-SOFCs

    International Nuclear Information System (INIS)

    Zhang, Leilei; Yao, Guibin; Song, Zhaoyuan; Niu, Bingbing; Long, Wen; Zhang, Lei; Shen, Yu; He, Tianmin

    2016-01-01

    Highlights: • Single phase oxides P_1_−_xBCO with x = 0.00–0.10 were successfully prepared. • TECs and electrical conductivities of P_1_−_xBCO cathodes decrease with Pr-deficiency. • Among P_1_−_xBCO cathodes, P_0_._9_2BCO exhibits the lowest polarization resistance. • Electron charge transfer plays a dominant role in cathode oxygen reduction. • P_m_a_x of 987 mW cm"−"2 at 800 °C for P_0_._9_2BCO cathode is obtained on SDC electrolyte. - Abstract: Pr-deficient Pr_1_−_xBaCo_2O_5_+_δ (P_1_−_xBCO) oxides are evaluated as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). Effects of Pr-deficiency on electrical conductivity, thermal expansion and electrochemical properties are investigated. Both the conductivity and thermal expansion coefficient (TEC) decrease with increasing Pr-deficiency. All of the conductivity, thermal expansion and TGA measurements demonstrate the existence of high temperature order-disorder transition. The oxygen reduction mechanism for P_1_−_xBCO cathodes are characterized by electrochemical impedance spectroscopy. Over the temperature range of 600−800 °C, the cathode polarization resistance is mainly contributed from electronic charge transfer over the cathode surface. Proper Pr-deficiency reduces cathode polarization resistance (R_p), and the lowest R_p (0.081 Ω cm"2 at 700 °C) is obtained for the P_0_._9_2BCO cathode. In addition, the effects of order-disorder transition on the properties of P_1_−_xBCO cathodes have also been discussed. Maximum power densities of a single-cell with P_0_._9_2BCO cathode on 300-μm thick Sm_0_._2Ce_0_._8O_1_._9 (SDC) electrolyte achieve 446–987 mW cm"−"2 at 650–800 °C. These results suggest that, among various P_1_−_xBCO oxides, P_0_._9_2BCO is the most promising candidate cathode material for IT-SOFCs.

  3. Synthesis and characterization of Ce{sub 1-x}SmXO{sub 2-(x/2)} as solid electrolyte for application in IT-SOFCs; Sintese e caracterizacao de Ce{sub 1-x}SmXO{sub 2-(x/2)} como eletrolito solido para aplicacao em IT-SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Nicodemo, J.P.; Martinelli, A.E.; Nascimento, R.M. [Universidade Federal do Rio Grande do Norte (DECM/UFRN), Natal, RN (Brazil). Dept. de Engenharia de Materiais], e-mail: juli_pivotto@yahoo.com.br; Melo, D.M.A. [Universidade Federal do Rio Grande do Norte (DQ/UFRN), Natal, RN (Brazil). Dept. de Quimica; Cela, B. [Universidade Federal do Rio Grande do Norte (PPGCEM/UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Macedo, D.A. [Universidade Federal do Rio Grande do Norte (PPGEM/UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica

    2008-07-01

    Mixed rare earth doped CeO{sub 2} oxide-based have been extensively studied for use in solid electrolytes for fuel cells. Ceramics-based CeO{sub 2} have high ionic conductivity and enable the operation of solid oxide fuel cells (SOFCs) in intermediate temperatures, in the range of 500 to 750 deg C. In this work, was investigated the Sm{sub 2}O{sub 3} doped CeO{sub 2} by Pechini method to obtain Ce{sub 0,9}Sm{sub 0,1}O{sub 1,95}. The resulting powders were characterized by the chemical composition (EDS) and crystallographic (XRD), thermal analysis (TG/ATD and DTG), and particles morphology (SEM). After calcinations of 500 and 700 deg C for 2 hours were obtained nanosized powders with crystalline structure of cubic phase type fluorite fully formed. (author)

  4. Design and Control of Integrated Systems for Hydrogen Production and Power Generation

    Science.gov (United States)

    Georgis, Dimitrios

    Growing concerns on CO2 emissions have led to the development of highly efficient power plants. Options for increased energy efficiencies include alternative energy conversion pathways, energy integration and process intensification. Solid oxide fuel cells (SOFC) constitute a promising alternative for power generation since they convert the chemical energy electrochemically directly to electricity. Their high operating temperature shows potential for energy integration with energy intensive units (e.g. steam reforming reactors). Although energy integration is an essential tool for increased efficiencies, it leads to highly complex process schemes with rich dynamic behavior, which are challenging to control. Furthermore, the use of process intensification for increased energy efficiency imposes an additional control challenge. This dissertation identifies and proposes solutions on design, operational and control challenges of integrated systems for hydrogen production and power generation. Initially, a study on energy integrated SOFC systems is presented. Design alternatives are identified, control strategies are proposed for each alternative and their validity is evaluated under different operational scenarios. The operational range of the proposed control strategies is also analyzed. Next, thermal management of water gas shift membrane reactors, which are a typical application of process intensification, is considered. Design and operational objectives are identified and a control strategy is proposed employing advanced control algorithms. The performance of the proposed control strategy is evaluated and compared with classical control strategies. Finally SOFC systems for combined heat and power applications are considered. Multiple recycle loops are placed to increase design flexibility. Different operational objectives are identified and a nonlinear optimization problem is formulated. Optimal designs are obtained and their features are discussed and compared

  5. Design and optimization of a combined fuel reforming and solid oxide fuel cell system with anode off-gas recycling

    International Nuclear Information System (INIS)

    Lee, Tae Seok; Chung, J.N.; Chen, Yen-Cho

    2011-01-01

    Highlights: → In this work, an analytical, parametric study is performed to evaluate the feasibility and performance of a combined fuel reforming and SOFC system. → Specifically the effects of adding the anode off-gas recycling and recirculation components and the CO 2 absorbent unit are investigated. → The AOG recycle ratio increases with increasing S/C ratio and the addition of AOG recycle eliminates the need for external water consumption. → The key finding is that for the SOFC operating at 900 deg. C with the steam to carbon ratio at 5 and no AOG recirculation, the system efficiency peaks. - Abstract: An energy conversion and management concept for a combined system of a solid oxide fuel cell coupled with a fuel reforming device is developed and analyzed by a thermodynamic and electrochemical model. The model is verified by an experiment and then used to evaluate the overall system performance and to further suggest an optimal design strategy. The unique feature of the system is the inclusion of the anode off-gas recycle that eliminates the need of external water consumption for practical applications. The system performance is evaluated as a function of the steam to carbon ratio, fuel cell temperature, anode off gas recycle ratio and CO 2 adsorption percentage. For most of the operating conditions investigated, the system efficiency starts at around 70% and then monotonically decreases to the average of 50% at the peak power density before dropping down to zero at the limiting current density point. From an engineering application point of view, the proposed combined fuel reforming and SOFC system with a range of efficiency between 50% and 70% is considered very attractive. It is suggested that the optimal system is the one where the SOFC operates around 900 deg. C with S/C ratio higher than 3, maximum CO 2 capture, and minimum AOG recirculation.

  6. Performance of strontium- and magnesium-doped lanthanum gallate electrolyte with lanthanum-doped ceria as a buffer layer for IT-SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dokyol; Han, Ju-Hyeong; Kim, Eun-Gu [Department of Materials Science and Engineering, Korea University, 5-1 Anam-dong, Seongbuk-gu, Seoul 136-713 (Korea); Song, Rak-Hyun; Shin, Dong-Ryul [Hydrogen and Fuel Cell Research Department, Korea Institute of Energy Research, 71-2 Jang-dong, Yuseong-gu, Daejeon 305-600 (Korea)

    2008-10-15

    La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.2}O{sub 2.8} (LSGM8080) powder, showing the highest electrical conductivity among LSGMs of various compositions, is synthesized using the glycine nitrate process (GNP) and used as the electrolyte for an intermediate-temperature solid oxide fuel cell (IT-SOFC). The LDC (Ce{sub 0.55}La{sub 0.45}O{sub 1.775}) powder is synthesized by a solid-state reaction and employed as the material for a buffer layer to prevent the reaction between the anode and electrolyte materials. The LDC also serves as the skeleton material for the anode. An anode-supported single cell with an active area of 1 cm{sup 2} is constructed for performance evaluation. A single-cell test is performed at 750 and 800 C. The maximum power density of the cell 459 and 664 mW cm{sup -2} at 750 and 800 C, respectively. (author)

  7. Performance of strontium- and magnesium-doped lanthanum gallate electrolyte with lanthanum-doped ceria as a buffer layer for IT-SOFCs

    Science.gov (United States)

    Lee, Dokyol; Han, Ju-Hyeong; Kim, Eun-Gu; Song, Rak-Hyun; Shin, Dong-Ryul

    La 0.8Sr 0.2Ga 0.8Mg 0.2O 2.8 (LSGM8080) powder, showing the highest electrical conductivity among LSGMs of various compositions, is synthesized using the glycine nitrate process (GNP) and used as the electrolyte for an intermediate-temperature solid oxide fuel cell (IT-SOFC). The LDC (Ce 0.55La 0.45O 1.775) powder is synthesized by a solid-state reaction and employed as the material for a buffer layer to prevent the reaction between the anode and electrolyte materials. The LDC also serves as the skeleton material for the anode. An anode-supported single cell with an active area of 1 cm 2 is constructed for performance evaluation. A single-cell test is performed at 750 and 800 °C. The maximum power density of the cell 459 and 664 mW cm -2 at 750 and 800 °C, respectively.

  8. Indirect adaptive soft computing based wavelet-embedded control paradigms for WT/PV/SOFC in a grid/charging station connected hybrid power system.

    Directory of Open Access Journals (Sweden)

    Sidra Mumtaz

    Full Text Available This paper focuses on the indirect adaptive tracking control of renewable energy sources in a grid-connected hybrid power system. The renewable energy systems have low efficiency and intermittent nature due to unpredictable meteorological conditions. The domestic load and the conventional charging stations behave in an uncertain manner. To operate the renewable energy sources efficiently for harvesting maximum power, instantaneous nonlinear dynamics should be captured online. A Chebyshev-wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking control paradigm is proposed for variable speed wind turbine-permanent synchronous generator (VSWT-PMSG. A Hermite-wavelet incorporated NeuroFuzzy indirect adaptive MPPT control strategy for photovoltaic (PV system to extract maximum power and indirect adaptive tracking control scheme for Solid Oxide Fuel Cell (SOFC is developed. A comprehensive simulation test-bed for a grid-connected hybrid power system is developed in Matlab/Simulink. The robustness of the suggested indirect adaptive control paradigms are evaluated through simulation results in a grid-connected hybrid power system test-bed by comparison with conventional and intelligent control techniques. The simulation results validate the effectiveness of the proposed control paradigms.

  9. High conductive and long-term phase stable anode materials for SOFCs: A2FeMoO6 (A = Ca, Sr, Ba)

    Science.gov (United States)

    Huan, Yu; Li, Yining; Yin, Baoyi; Ding, Dong; Wei, Tao

    2017-08-01

    In this work, the mixed oxide-ion/electron conductor (MIEC) double-perovskite compounds A2FeMoO6 (AFMO, A = Ca, Sr, Ba) are investigated as anode materials for O2--ion conducting solid-oxide fuel cells (SOFCs). Several advantages are outlined here; 1) under H2 atmosphere, the conductivities of Ba2FeMoO6 (BFMO), Sr2FeMoO6 (SFMO) and Ca2FeMoO6 (CFMO) reach as high as 243, 302 and 561 S cm-1, respectively, which can be comparable with the commercial NiO-electrolyte anode; 2) excellent structure and phase stability at high temperature and in H2 atmosphere; 3) matched thermodynamic compatibility (such as TECs) with electrolyte materials; 4) fast oxidization for fuel with O2- ions accepted by oxygen vacancies from the electrolyte. Moreover, with H2 as fuel gas, the cell power output, cell's long-term stabilities and the structural parameter are also been examined to evaluate the AFMO anode.

  10. Indirect adaptive soft computing based wavelet-embedded control paradigms for WT/PV/SOFC in a grid/charging station connected hybrid power system.

    Science.gov (United States)

    Mumtaz, Sidra; Khan, Laiq; Ahmed, Saghir; Bader, Rabiah

    2017-01-01

    This paper focuses on the indirect adaptive tracking control of renewable energy sources in a grid-connected hybrid power system. The renewable energy systems have low efficiency and intermittent nature due to unpredictable meteorological conditions. The domestic load and the conventional charging stations behave in an uncertain manner. To operate the renewable energy sources efficiently for harvesting maximum power, instantaneous nonlinear dynamics should be captured online. A Chebyshev-wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking) control paradigm is proposed for variable speed wind turbine-permanent synchronous generator (VSWT-PMSG). A Hermite-wavelet incorporated NeuroFuzzy indirect adaptive MPPT control strategy for photovoltaic (PV) system to extract maximum power and indirect adaptive tracking control scheme for Solid Oxide Fuel Cell (SOFC) is developed. A comprehensive simulation test-bed for a grid-connected hybrid power system is developed in Matlab/Simulink. The robustness of the suggested indirect adaptive control paradigms are evaluated through simulation results in a grid-connected hybrid power system test-bed by comparison with conventional and intelligent control techniques. The simulation results validate the effectiveness of the proposed control paradigms.

  11. Molten salt synthesis of La0.8Sr0.2MnO3 powders for SOFC cathode electrode

    Science.gov (United States)

    Gu, Sin-il; Shin, Hyo-soon; Hong, Youn-woo; Yeo, Dong-hun; Kim, Jong-hee; Nahm, Sahn; Yoon, Sang-ok

    2012-08-01

    For La0.8Sr0.2MnO3 (LSM) perovskite, used as the cathode material for solid oxide fuel cells (SOFC), it is known that the formation of a triple-phase-boundary is restrained due to the formation of a second phase at the YSZ/electrode interface at high temperature. To decrease the 2nd phase, lowering the sintering temperature has been used. LSM powder was synthesized by molten salt synthesis method to control its particle size, shape, and agglomeration. We have characterized the phase formation, particle size, shape, and sintering behavior of LSM in the synthesis using the variation of KCl, LiCl, KF and its mixed salts as raw materials. In the case of KCl and KCl-KF salts, the particle size and shape of the LSM was well controlled and synthesized. However, in the case of LiCl and KCl-LiCl salts, LiMnOx as 2nd phase and LSM were synthesized simultaneously. In the case of the mixed salt of KCl-KF, the growth mechanism of the LSM particle was changed from `diffusion-controlled' to `reaction-controlled' according to the amount of mixed salt. The sintering temperature can be decreased below 1000 °C by using the synthesized LSM powder.

  12. Indirect adaptive soft computing based wavelet-embedded control paradigms for WT/PV/SOFC in a grid/charging station connected hybrid power system

    Science.gov (United States)

    Khan, Laiq; Ahmed, Saghir; Bader, Rabiah

    2017-01-01

    This paper focuses on the indirect adaptive tracking control of renewable energy sources in a grid-connected hybrid power system. The renewable energy systems have low efficiency and intermittent nature due to unpredictable meteorological conditions. The domestic load and the conventional charging stations behave in an uncertain manner. To operate the renewable energy sources efficiently for harvesting maximum power, instantaneous nonlinear dynamics should be captured online. A Chebyshev-wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking) control paradigm is proposed for variable speed wind turbine-permanent synchronous generator (VSWT-PMSG). A Hermite-wavelet incorporated NeuroFuzzy indirect adaptive MPPT control strategy for photovoltaic (PV) system to extract maximum power and indirect adaptive tracking control scheme for Solid Oxide Fuel Cell (SOFC) is developed. A comprehensive simulation test-bed for a grid-connected hybrid power system is developed in Matlab/Simulink. The robustness of the suggested indirect adaptive control paradigms are evaluated through simulation results in a grid-connected hybrid power system test-bed by comparison with conventional and intelligent control techniques. The simulation results validate the effectiveness of the proposed control paradigms. PMID:28877191

  13. Mathematical Modeling Analysis and Optimization of Key Design Parameters of Proton-Conductive Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Hong Liu

    2014-01-01

    Full Text Available A proton-conductive solid oxide fuel cell (H-SOFC has the advantage of operating at higher temperatures than a PEM fuel cell, but at lower temperatures than a SOFC. This study proposes a mathematical model for an H-SOFC in order to simulate the performance and optimize the flow channel designs. The model analyzes the average mass transfer and species’ concentrations in flow channels, which allows the determination of an average concentration polarization in anode and cathode gas channels, the proton conductivity of electrolyte membranes, as well as the activation polarization. An electrical circuit for the current and proton conduction is applied to analyze the ohmic losses from an anode current collector to a cathode current collector. The model uses relatively less amount of computational time to find the V-I curve of the fuel cell, and thus it can be applied to compute a large amount of cases with different flow channel dimensions and operating parameters for optimization. The modeling simulation results agreed satisfactorily with the experimental results from literature. Simulation results showed that a relatively small total width of flow channel and rib, together with a small ratio of the rib’s width versus the total width, are preferable for obtaining high power densities and thus high efficiency.

  14. Análise termodinâmica de um ciclo de potência com célula a combustível sofc e turbina a vapor - DOI: 10.4025/actascitechnol.v28i1.1287

    Directory of Open Access Journals (Sweden)

    Alexandre Sordi

    2006-03-01

    Full Text Available O objetivo deste artigo foi realizar a análise termodinâmica de um sistema híbrido, SOFC / ST (célula a combustível tipo SOFC e turbina a vapor ST. O combustível considerado para a análise foi o gás metano (biogás produzido por meio da digestão anaeróbica de resíduos orgânicos. A metodologia utilizada foi o balanço de energia do sistema SOFC / ST, considerando a reforma interna do metano na célula a combustível, de forma a obter a sua eficiência elétrica. O resultado foi comparado a um ciclo combinado convencional de turbina a gás e turbina a vapor (GT / ST para potências entre 10 MW e 30 MW. A eficiência do sistema híbrido SOFC / ST variou de 61% a 66% em relação ao poder calorífico do metano; e a eficiência do ciclo combinado GT / ST variou de 41% a 55% para o mesmo intervalo de potência. Para geração distribuída a célula a combustível SOFC é a tecnologia mais eficiente.

  15. Fuel cell electric vehicle as a power plant and SOFC as a natural gas reformer : An exergy analysis of different system designs

    NARCIS (Netherlands)

    Fernandes, A.A.; Woudstra, T.; van Wijk, A.J.M.; Verhoef, L.A.; Purushothaman Vellayani, A.

    2016-01-01

    Delft University of Technology, under its "Green Village" programme, has an initiative to build a power plant (car parking lot) based on the fuel cells used in vehicles for motive power. It is a trigeneration system capable of producing electricity, heat, and hydrogen. It comprises three main

  16. Design and performance of tubular flat-plate solid oxide fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, T.; Ikeda, D.; Kanagawa, H. [NTT Integrated Information & Energy Systems Labs., Tokyo (Japan)] [and others

    1996-12-31

    With the growing interest in conserving the environmental conditions, much attention is being paid to Solid Oxide Fuel Cell (SOFC), which has high energy-conversion efficiency. Many organizations have conducted studies on tubular and flat type SOFCs. Nippon Telegraph and Telephone Corporation (NTT) has studied a combined tubular flat-plate SOFC, and already presented the I-V characteristics of a single cell. Here, we report the construction of a stack of this SOFC cell and successful generation tests results.

  17. Sinterización de vidrios del sistema RO-BaO-SiO2 (R= Mg, Zn para el sellado de SOFC

    Directory of Open Access Journals (Sweden)

    Lara, C.

    2007-04-01

    Full Text Available Glasses of composition 50SiO2•30BaO•20ZnO, mol% (Zn1.5-50, 55SiO2•27BaO•18ZnO, mol% (Zn1.5-55, and 55SiO2•27BaO•18MgO, mol% (Mg1.5-55 present good properties for application in sealing planar solid oxide fuel cells with an intermediate temperature of operation (850ºC (IT-SOFC. The sealing must take place on sintering the glass powder during the start-up of the cell between 700 and 850ºC. Further treatment at the operation temperature provokes the crystallisation of barium silicates with the subsequent increase of viscosity and seal rigidity. This work is a study of the sintering behaviour of these glasses using different heating rates and particle-size distributions of the glass powder in order to obtain dense and homogeneous seals. The glasses Zn1.5-55 and Mg1.5-55 with a particle size less than 63 μm heated at 2ºC/min reach final densities higher than 95%. A good agreement has been demonstrated between the measured sintering kinetics and those predicted with the sintering model of Clusters formation in the absence of concurrent crystallisation.

    Los vidrios de composición molar 50SiO2•30BaO•20ZnO (Zn1.5-50, 55SiO2•27BaO•18ZnO (Zn1.5-55, y 55SiO2•27BaO•18MgO (Mg1.5-55 presentan buenas propiedades para su aplicación en el sellado de pilas de combustible de óxido sólido de configuración plana y temperatura de operación intermedia (850ºC (IT-SOFC. El sellado debe producirse a través de la sinterización del polvo de vidrio, durante el arranque de la pila, a temperaturas entre 700 y 850ºC. El tratamiento posterior a la temperatura de operación da lugar a la cristalización de silicatos de bario con el consiguiente aumento de viscosidad y rigidez del sello. Este trabajo es un estudio del comportamiento de sinterización de estos vidrios utilizando diferentes velocidades de calentamiento y distribuciones de tamaño de partícula del polvo de vidrio, para la obtención final de sellos densos y homog

  18. Study of synthesis routes and processing of NiO-YSZ ceramic composite for use as anode in solid oxide fuel cell (SOFC)

    International Nuclear Information System (INIS)

    Yoshito, Walter Kenji

    2011-01-01

    This study aim the definition of synthesis and ceramic processing conditions of the anodic component suitable for operation of SOFC, i.e, homogeneous distribution of NiO in YSZ matrix and porosity after reduction above 30%. The selected synthesis routes included the co-precipitation in ammonia media, mechanical mixing of powders and combustion reaction from nitrate salts. The characterization techniques of powders included the X-ray diffraction, scanning and transmission electron microscopy, laser diffraction, nitrogen gas adsorption technique (BET) and Helium pycnometry. The obtained results indicated that the loss of Ni 2+ in co-precipitation process, due to the formation of complex [Ni(NH 3 ) n ] 2+ , can be minimized by controlling the pH around 9.3, keeping the concentration of nickel cation in the solution to be precipitated around 0.1M. In the mechanical mixing method the best condition of powder dispersion, without differential sedimentation, was obtained for zeta potential values at pH around 8.0, fixing the dispersant concentration at 0.8%. For the combustion synthesis it was observed that when stoichiometric and twofold stoichiometric urea was used, amorphous phase was formed and a higher surface area was attained in the final products. Employing the fuel-rich solution condition, crystallization of the powder was observed and the relative intensity of reflections of XRD patterns increased with excess of fuel, due to increasing the reaction temperature. Sinterability studies of pellets prepared from powder synthesized by the three routes described above showed the temperature around 1300 deg C for maximum rate densification and porosity between 6.0 and 14%. Reduction results of the composites confirmed that the reduction kinetics occurs in two steps. The first one with a linear behavior and controlled by chemical reaction on the surface. The second reduction step is the reduction that is controlled by gas diffusion in micro pores, generated by reduction

  19. Thermal Design for Extra-Terrestrial Regenerative Fuel Cell System

    Science.gov (United States)

    Gilligan, R.; Guzik, M.; Jakupca, I.; Bennett, W.; Smith, P.; Fincannon, J.

    2017-01-01

    The Advanced Exploration Systems (AES) Advanced Modular Power Systems (AMPS) Project is investigating different power systems for various lunar and Martian mission concepts. The AMPS Fuel Cell (FC) team has created two system-level models to evaluate the performance of regenerative fuel cell (RFC) systems employing different fuel cell chemistries. Proton Exchange Membrane fuel cells PEMFCs contain a polymer electrolyte membrane that separates the hydrogen and oxygen cavities and conducts hydrogen cations (protons) across the cell. Solid Oxide fuel cells (SOFCs) operate at high temperatures, using a zirconia-based solid ceramic electrolyte to conduct oxygen anions across the cell. The purpose of the modeling effort is to down select one fuel cell chemistry for a more detailed design effort. Figures of merit include the system mass, volume, round trip efficiency, and electrolyzer charge power required. PEMFCs operate at around 60 C versus SOFCs which operate at temperatures greater than 700 C. Due to the drastically different operating temperatures of the two chemistries the thermal control systems (TCS) differ. The PEM TCS is less complex and is characterized by a single pump cooling loop that uses deionized water coolant and rejects heat generated by the system to the environment via a radiator. The solid oxide TCS has its own unique challenges including the requirement to reject high quality heat and to condense the steam produced in the reaction. This paper discusses the modeling of thermal control systems for an extraterrestrial RFC that utilizes either a PEM or solid oxide fuel cell.

  20. FY 1993 report on the results of the commissioned research and development project. R and D of SOFC (solid oxide fuel cells); 1983 nendo nenryo denchi hatsuden gijutsu kaihatsu seika hokokusho. SOFC kotai denkaishitsugata nenryo denchi no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-05-01

    The research and development project is carried out for fuel cell power generation technologies and solid electrolyte type fuel cells, and the reports on the FY 1993 results issued by the participant organizations are summarized. For R and D of the modules, Fuji Electric conducted the R and D for the large-area, cell-stacked type, and Sanyo Electric for the composite cell-stacked type. For R and D of the materials and fundamental technologies, Fine Ceramics Center conducted the R and D for microscopic structures of the electrode, Fujikura for electrode structures produced by spraying or the like, Mitsubishi Heavy Industries for multi-functional fuel electrodes, Murata Seisakusho for co-sintering technologies, and Mitsui Shipbuilding for current collecting technologies. For R and D of the systems, Central Research Institute of Electric Power Industry conducted the R and D for the systems, Electric Power Development and Mitsubishi Heavy Industries jointly for designs of the cell peripheries, and the Japan Research and Development Center for Metals for elementary technologies for the peripheral devices. (NEDO)

  1. FY 1992 report on the results of the commissioned research and development project. R and D of SOFC (solid oxide fuel cells); 1992 nendo nenryo denchi hatsuden gijutsu kaihatsu seika hokokusho. SOFC kotai denkaishitsugata nenryo denchi no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1983-05-01

    The research and development project is carried out for fuel cell power generation technologies and solid electrolyte type fuel cells, and the reports on the FY 1992 results issued by the participant organizations are summarized. For R and D of the modules, Fuji Electric conducted the R and D for the large-area, cell-stacked type, and Sanyo Electric for the composite cell-stacked type. For R and D of the materials and fundamental technologies, Fine Ceramics Center is conducted the R and D for microscopic structures of the electrode, Fujikura for electrode structures produced by spraying or the like, Mitsubishi Heavy Industries for multi-functional fuel electrodes, Murata Seisakusho for co-sintering technologies, and Mitsui Shipbuilding for current collecting technologies. For R and D of the systems, Central Research Institute of Electric Power Industry conducted the R and D for the systems, Electric Power Development and Mitsubishi Heavy Industries jointly for designs of the cell peripheries, and the Japan Research and Development Center for Metals for elementary technologies for the peripheral devices. (NEDO)

  2. Characterization of cathode materials SrCoO3 and La0,2Sr0,8CoO3 for use in solid oxide fuel cells (SOFC); Caracterizacao de materiais catodicos SrCoO3 e La0,2Sr0,8CoO3 para aplicacao em celulas a combustivel de oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Galvao, G.O.; Aquino, F.M; Silva, R.M.; Medeiros, I.D.M. de, E-mail: gabriela.galvao@cear.ufpb.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)

    2016-07-01

    Mixed oxide ceramics with chemical structure of ABO{sub 3} type are promising candidates for cathodes of solid oxide fuel cells (SOFC) for performing well on the electrical conductivity and thermal stability. Various methods of preparation have been studied and used for the synthesis of these materials. In this study, SrCoO{sub 3} and La{sub 0,2}Sr{sub 0,8}CoO{sub 3} perovskites were synthesized using gelatin as directing agent with the purpose of producing homogeneous and porous particles. The powders obtained at 350 ° C / 2 h were calcined at 600, 800 and 1000 ° C for 4 hours and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that gelatin is a good polymerizing agent for metal ions as the material showed characteristic peaks of perovskite, with good porosity and uniformity. Furthermore, the method of synthesis employed has advantages related to cost and toxicity, which are very low. (author)

  3. Polarization properties of La0.6Sr0.4Co0.2Fe0.8O3-based double layer-type oxygen electrodes for reversible SOFCs

    International Nuclear Information System (INIS)

    Tao, Y.; Nishino, H.; Ashidate, S.; Kokubo, H.; Watanabe, M.; Uchida, H.

    2009-01-01

    We have developed double layer-type (catalyst layer/current collecting layer) oxygen electrodes (DLE) for reversible SOFCs. As the catalyst layer (cathode for SOFC and anode for steam electrolysis) interfaced with a samaria-doped ceria [(CeO 2 ) 0.8 (SmO 1.5 ) 0.2 , SDC] interlayer/YSZ solid electrolyte, mixed conducting La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) and SDC particles were employed. The current collecting porous LSCF layer was formed on the catalyst layer. By controlling the SDC content, as well as the thickness and porosity of the catalyst layer, the gas diffusion rate and the conduction networks for electrons and oxide ions were optimized, resulting in a marked reduction of the overpotential. The LSCF + SDC/LSCF DLE exhibited higher performance than single-layer electrodes of LSCF + SDC or LSCF; the IR-free anode potential vs. an air reference electrode was 0.12 V (corresponding to an overpotential of 0.08 V) at 0.5 A cm -2 and 900 deg. C under an atmosphere of O 2 (1 atm)

  4. A-site order–disorder in the NdBaMn2O5+δ SOFC electrode material monitored in situ by neutron diffraction under hydrogen flow

    KAUST Repository

    Tonus, Florent

    2017-05-11

    The A-site disordered perovskite manganite, Nd0.5Ba0.5MnO3, has been obtained by heating the A-site-ordered and vacancy ordered layered double perovskite, NdBaMn2O5, in air at 1300 °C for 5 h. Combined transmission electron microscopy (TEM) images and neutron powder diffraction (NPD) analysis at 25 °C revealed that Nd0.5Ba0.5MnO3 has a pseudotetragonal unit cell with orthorhombic symmetry (space group Imma, √2ap × 2ap × √2ap) at 20 °C with the cell dimensions a = 5.503(1) Å, b = 7.7962(4) Å, c = 5.502(1) Å, in contrast to Pm[3 with combining macron]m or Cmcm that have been previously stated from X-ray diffraction studies. The in situ neutron diffraction study carried out on Nd0.5Ba0.5MnO3 in hydrogen flow up to T ∼ 900 °C, allows monitoring the A-site cation disorder–order structural phase transition of this representative member of potential SOFC anode materials between air sintering conditions and hydrogen working conditions. Oxygen loss from Nd0.5Ba0.5MnO3 proceeds with retention of A-site disorder until the oxygen content reaches the Nd0.5Ba0.5MnO2.5 composition at 600 °C. The phase transition to layered NdBaMn2O5 and localization of the oxygen vacancies in the Nd layer proceeds at 800 °C with retention of the oxygen content. Impedance spectroscopy measurements for the oxidized A-site ordered electrode material, NdBaMn2O6, screen printed on a Ce0.9Gd0.1O2−δ (CGO) electrolyte showed promising electrochemical performance in air at 700 °C with a polarization resistance of 1.09 Ω cm2 without any optimization.

  5. Fiscal 2000 project of inviting proposals for international joint research - invitation for international proposal (Power generation No.2). Achievement report on development of high-efficiency low-temperature power generation device using SOFC containing yttria-doped ceria layer; 2000 nendo kokusai kyodo kenkyu teian kobo jigyo - kokusai teian kobo (hatsuden No.2). Yttria gan'yu ceria so wo yusuru SOFC kokoritsu teion sadogata hatsuden sochi no kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Efforts continue to develop a solid oxide fuel cell (SOFC) capable of consuming methane, propane, and the like, as fuel directly and of operation at 650 degrees C or lower. The efforts in concrete terms involve the development of an anode material, an electrolyte, and a cathode material not to suffer carbon precipitation and the evaluation of power generation performance of a hydrocarbon fueled single cell. Activities are conducted in the five domains of (1) the fabrication of an SOFC single cell and a preliminary study, (2) evaluation of solid electrolyte thermal stability using X-ray diffraction, (3) anodic carbon precipitation test and single cell performance test, (4) survey of technical trends overseas, and (5) the goal and self-management. In domain (1), technologies are developed to form thin film anodes of Ni-GDC (gadolinium-doped ceria), Cu-GDC, Ni-YSZ (yttria-stabilized zirconia), and the like, for which the ultrasonic spray method and slurry coat method are used. In the study of cell manufacturing, the anode support method and cathode support method are investigated. The anode support method is used to fabricate a thin film, a thin YSZ film is successfully fabricated for typical Ni-YSZ. (NEDO)

  6. Characterization of cathode materials SrCoO3 and La0,2Sr0,8CoO3 for use in solid oxide fuel cells (SOFC)

    International Nuclear Information System (INIS)

    Galvao, G.O.; Aquino, F.M; Silva, R.M.; Medeiros, I.D.M. de

    2016-01-01

    Mixed oxide ceramics with chemical structure of ABO_3 type are promising candidates for cathodes of solid oxide fuel cells (SOFC) for performing well on the electrical conductivity and thermal stability. Various methods of preparation have been studied and used for the synthesis of these materials. In this study, SrCoO_3 and La_0_,_2Sr_0_,_8CoO_3 perovskites were synthesized using gelatin as directing agent with the purpose of producing homogeneous and porous particles. The powders obtained at 350 ° C / 2 h were calcined at 600, 800 and 1000 ° C for 4 hours and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that gelatin is a good polymerizing agent for metal ions as the material showed characteristic peaks of perovskite, with good porosity and uniformity. Furthermore, the method of synthesis employed has advantages related to cost and toxicity, which are very low. (author)

  7. La0.3Sr0.2Mn0.1Zn0.4 oxide-Sm0.2Ce0.8O1.9 (LSMZ-SDC) nanocomposite cathode for low temperature SOFCs.

    Science.gov (United States)

    Raza, Rizwan; Abbas, Ghazanfar; Liu, Qinghua; Patel, Imran; Zhu, Bin

    2012-06-01

    Nanocomposite based cathode materials compatible for low temperature solid oxide fuel cells (LTSOFCs) are being developed. In pursuit of compatible cathode, this research aims to synthesis and investigation nanocomposite La0.3Sr0.2Mn0.1Zn0.4 oxide-Sm0.2Ce0.8O1.9 (LSMZ-SDC) based system. The material was synthesized through wet chemical method and investigated for oxide-ceria composite based electrolyte LTSOFCs. Electrical property was studied by AC electrochemical impedance spectroscopy (EIS). The microstructure, thermal properties, and elemental analysis of the samples were characterized by TGA/DSC, XRD, SEM, respectively. The AC conductivity of cathode was obtained for 2.4 Scm(-1) at 550 degrees C in air. This cathode is compatible with ceria-based composite electrolytes and has improved the stability of the material in SOFC cathode environment.

  8. Study of LnBaCo{sub 2}O{sub 6-d}elta (Ln = Pr, Nd, Sm and Gd) double perovskites as new cathode material for IT-SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, E; Mueller, M; Mogni, L; Caneiro, A, E-mail: mogni@cab.cnea.gov.a [Centro Atomico Bariloche-CNEA, Instituto Balseiro. Av. Bustillo 9500, S. C. de Bariloche 8400 (Argentina)

    2009-05-01

    Oxides with double perovskites structures of general composition LnBaCo{sub 2}O{sub 6-d}elta (Ln = Pr, Nd, Sm and Gd) were synthesized by solid state reaction with the purpose to evaluate new materials to be used as cathodes in intermediate temperature solid oxide fuel cell (IT-SOFC). A preliminary study about electrochemical properties was performed by impedance spectroscopy between 500 and 800 deg. C under atmosphere of pure O{sub 2}. Symmetrical cells were obtained by spray deposition of LnBaCo{sub 2}O{sub 6-d}elta (Ln = Pr, Nd, Sm and Gd) at both sides of a dense ceramic electrolyte. The impedance spectroscopy measurements as a function of temperatures show a hysteresis loop which could be associated to a tetragonal/orthorhombic phase transition. The existence of this transition was corroborated by high temperature X-Ray diffraction and Differential Scanning Calorimetry measurements.

  9. Impregnación de la perovskita La0.8Sr0.2Cr0.5Mn0.5O3-δ como ánodo en celdas SOFC

    Directory of Open Access Journals (Sweden)

    José Juan Alvarado Flores

    2015-09-01

    Full Text Available Se han sintetizado a través del método sol-gel, y caracterizado por varias técnicas, nuevos compósitos tipo perovskita de La0,8Sr0,2Cr0,5Mn0,5O3-δ (LSCM, utilizando cobre (XCu; X = 25, 35 y 45% como aditivo formador del cermet LSCM + Cu para utilizarse como ánodos alternativos en celdas de combustible de óxido sólido de temperatura intermedia (IT-SOFC. Se confirma por difracción de rayos X (XRD la formación de fase de los cermets LSCM-Cu. La conductividad eléctrica obtenida desde temperatura ambiente hasta 800 °C indica la presencia de 2 tipos de comportamiento tanto semiconductor como metálico. Cuando la concentración de Cu fue del 25 y del 35%, el comportamiento que dominó fue del tipo semiconductor. La determinación de los coeficientes de expansión térmica (TEC mostró una dependencia lineal inversamente proporcional a la concentración de Cu. Nuestros resultados de conductividad eléctrica, análisis morfológico y TEC sugieren que los ánodos con 25 y 35% de Cu tienen la mayor posibilidad para aplicarse en las celdas tipo SOFC-IT.

  10. Symmetry breaking and electrical conductivity of La0.7Sr0.3Cr0.4Mn0.6O3-δ perovskite as SOFC anode material

    International Nuclear Information System (INIS)

    Reyes-Rojas, A.; Alvarado-Flores, J.; Esparza-Ponce, H.; Esneider-Alcala, M.; Espitia-Cabrera, I.; Torres-Moye, E.

    2011-01-01

    Research highlights: → Perovskite-type La 0.7 Sr 0.3 Cr 0.4 Mn 0.6 O 3-δ -NiO nucleation kinetics. Symmetry-breaking by introducing Ni 2+ cations at 1050 deg. C. Phase transition from high temperature aristotype R3-bar c to hettotype I4/mmm. At low Ni concentration ρ resistivity decreases when increasing the temperature. For Ni concentration higher than 25% ρ resistivity increases. - Abstract: This work is focused on nanocrystalline solid oxide fuel cell synthesis and characterization (SOFC) anodes of La 0.7 Sr 0.3 Cr 0.4 Mn 0.6 O 3-δ (perovskite-type) with Nickel. Perovskite-type oxide chemical reactivity, nucleation kinetics and phase composition related with La 0.7 Sr 0.3 Cr 0.4 Mn 0.6 O 3-δ -NiO to La 0.7 Sr 0.3 Cr 0.4 Mn 0.6 O 3-δ -Ni transformation have been analyzed. SOFC anode powders were obtained by sol-gel synthesis, using polyvinyl alcohol as an organic precursor to get a porous cermet electrode after sintering at 1365 deg. C and oxide reduction by hydrogen at 800 deg. C/1050 deg. C for 8 h in a horizontal tubular reactor furnace under 10% H 2 /N 2 atmosphere. Composite powders were compressed into 10-mm diameter discs with 25-75 wt% Ni. Electrical and structural characterization by four-point probe method for conductivity, scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Rietveld method were carried out. Symmetry-breaking by phase transition from high temperature aristotype R3-bar c to hettotype I4/mmm has been identified and confirmed by XRD and Rietveld method which can be produced by introducing Ni 2+ cations in the perovskite solid solution. Rietveld analysis suggests that Ni contents are directly proportional to La 0.7 Sr 0.3 Cr 0.4 Mn 0.6 NiO 3.95 tetragonal structure cell volume and inversely proportional to Ni cubic structure cell volume after reduction at 1050 deg. C. Kinetic analysis indicated that the Johnson-Mehl-Avrami equation is able to provide a good fit to phase

  11. Combustion synthesis of NiO–Ce0.9Gd0.1O1.95 nanocomposite anode and its electrical characteristics of semi-cell configured SOFC assembly

    International Nuclear Information System (INIS)

    Akbari-Fakhrabadi, A.; Avila, Ricardo E.; Carrasco, Hector E.; Ananthakumar, S.; Mangalaraja, R.V.

    2012-01-01

    Highlights: ► Combustion synthesis was followed to prepare NiO–GDC nanocomposite. ► NiO–GDC anode was applied over GDC electrolyte to fabricate a semi-cell. ► Electrical conductivity of the semi-cell was characterized. ► Structure, composition, particle size and morphology of NiO–GDC were studied. - Abstract: NiO–Ce 0.9 Gd 0.1 O 1.95 (NiO–10GDC) nanocomposite anode material was synthesized through combustion technique for possible low temperature solid oxide fuel cells (LT–SOFCs). A low weight loss is seen in the TG/DTA thermogram that indicates the complete combustion of the reactant mixtures. The powder X-ray diffraction patterns showed that the presence of NiO, GDC and Ni crystallite phases in the as combusted product. Upon calcination at 600 °C, the metallic Ni oxidized to NiO. TEM images showed a wide size distribution of fine spherical GDC and large irregularly shaped NiO particles. This NiO–10GDC anode material was applied over GDC electrolyte as a porous thin layer. Using this surface engineered GDC electrolyte a semi-cell (electrode/electrolyte structure) was fabricated. The electrical conductivity of the semi-cell was characterized with respect to temperature.

  12. Nanostructured thin film La{sub 0.6}Sr{sub 0.4}CoO{sub 3-δ} synthesized via salt-assisted spray pyrolysis for micro-SOFC application

    Energy Technology Data Exchange (ETDEWEB)

    Benel, Cahit; Darbandi, Azad J. [Institute for Nanotechnology, Karlsruhe Institute of Technology (Germany); Joint Research Laboratory Nanomaterials/Technische Universitaet Darmstadt and Karlsruhe Institute of Technology (Germany); Center for Functional Nanostructures, Karlsruhe Institute of Technology (Germany); Evans, Anna; Toelke, Rene [Nonmetallic Inorganic Materials, Department of Materials, ETH Zurich (Switzerland); Hahn, Horst [Institute for Nanotechnology, Karlsruhe Institute of Technology (Germany); Joint Research Laboratory Nanomaterials/Technische Universitaet Darmstadt and Karlsruhe Institute of Technology (Germany)

    2012-07-01

    Micro-solid oxide fuel cells (micro-SOFCs) are anticipated for battery replacement due to their increased energy capacity for applications such as portable electronic devices, mobile phones and laptops. In this work, nanocrystalline La{sub 0.6}Sr{sub 0.4}CoO{sub 3-δ} (LSC) powder with ultrafine microstructure and high specific surface area was synthesized via salt-assisted spray pyrolysis method. XRD results show the formation of a nanocrystalline single phase perovskite structure. Agglomerate-free LSC nanoparticles were stabilized in water-based dispersion without the need of ultrasonic energy application. Nanoparticulate cathode thin films of LSC with thickness between 150 and 500 nm were prepared via single step spin coating on yttria stabilized zirconia (YSZ) substrates. Gadolinium doped ceria (GDC) film was applied to YSZ substrate to avoid the chemical reaction between cathode and electrolyte. The performance of the thin film cathodes was evaluated by high temperature impedance spectroscopy on symmetrical samples.

  13. Physical and thermal behaviour of Sr-La-Al-B-Si based SOFC glass sealants as function of SrO content and B2O3/SiO2 ratio in the matrix

    Science.gov (United States)

    Ojha, Prasanta Kumar; Rath, S. K.; Chongdar, T. K.; Gokhale, N. M.; Kulkarni, A. R.

    2011-05-01

    A series of SOFC glass sealants with composition SrO (x), La2O3 (15), Al2O3 (15), B2O3 (40 - x), and SiO2 (30) [x = 10, 15, 20, 25 and 30] (wt.%) [SLABS] are investigated for their structure property correlations at different compositions. Quantitative Fourier transform infrared spectroscopy shows structural rigidity with increasing SrO content, as demonstrate by an increase in the Si-O-Si/O-Si-O bending and B-O-B stretching frequencies. The role of SrO as a modifier dominates the control of the structure and behaviour of glasses compared with the effect of network formers, i.e., the B2O3/SiO2 ratio. Consequent to the structural changes, increasing substitution of B2O3 by SrO the glasses causes increases in the density, glass transition temperature and dilatometric softening point. On the other hand, the crystallization temperatures show a decreasing trend and the coefficient of thermal expansion increases with increase in substitution.

  14. Effect of propellant on the combustion synthesis of La07Sr0.3Co0.5Fe0.5O3 (LSCF) nanopowders for application as cathode in IT-SOFC

    International Nuclear Information System (INIS)

    Silva, Amada M.; Silva, Camila R.B.; Conceicao, Leandro da; Souza, Mariana M.V.M.; Ribeiro, Nielson F.P.

    2009-01-01

    Combustion synthesis has emerged as a simple and economically viable technique for the preparation of La 0,7 Sr 0,3 Co 0 ,5Fe 0,5 O 3 (LSCF) nanopowders. This material has attracted a substantial interest for application as cathode in the solid oxide fuel cells of intermediate temperature (IT-SOFC). The objective of this work is to study the effect of different propellants (urea, glycine, citric acid and sucrose) in the preparation of LSCF nanopowders by combustion method. The nitrates and the propellant were mixed on a hot plate (150 °C) and then introduced in a furnace (300°C), where the flame temperature is measured by thermocouple. The powder was finally calcined at different temperatures. The obtained materials were characterized by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The results obtained by XRD showed the presence of pure perovskite LSFC and a small formation of carbonate phases, but when urea and sucrose were used as propellant these secondary phases were almost nonexistent. (author)

  15. Design Methodology - Design Synthesis

    DEFF Research Database (Denmark)

    Andreasen, Mogens Myrup

    2003-01-01

    Design Methodology is part of our practice and our knowledge about designing, and it has been strongly supported by the establishing and work of a design research community. The aim of this article is to broaden the reader¿s view of designing and Design Methodology. This is done by sketching...... the development of Design Methodology through time and sketching some important approaches and methods. The development is mainly forced by changing industrial condition, by the growth of IT support for designing, but also by the growth of insight into designing created by design researchers.......ABSTRACT Design Methodology shall be seen as our understanding of how to design; it is an early (emerging late 60ies) and original articulation of teachable and learnable methodics. The insight is based upon two sources: the nature of the designed artefacts and the nature of human designing. Today...

  16. Designing Material Materialising Design

    DEFF Research Database (Denmark)

    Nicholas, Paul

    2013-01-01

    Designing Material Materialising Design documents five projects developed at the Centre for Information Technology and Architecture (CITA) at the Royal Danish Academy of Fine Arts, School of Architecture. These projects explore the idea that new designed materials might require new design methods....... Focusing on fibre reinforced composites, this book sustains an exploration into the design and making of elastically tailored architectural structures that rely on the use of computational design to predict sensitive interdependencies between geometry and behaviour. Developing novel concepts...

  17. Design of Waste Gasification Energy Systems with Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2017-01-01

    Energy saving is an open point in most European countries where energy policies are oriented to reduce the use of fossil fuels, greenhouses emissions and energy independence, and to increase the use of renewable energies. In the last several years, new technologies have been developed and some...... of them received subsidies to increase installation and reduce cost. This article presents a new sustainable trigeneration system (power, heat and cool) based on a solid oxide fuel cell (SOFC) system integrated with an absorption chiller for special applications such as hotels, resorts, hospitals, etc....... with a focus on plant design and performance. The proposal system is based on the idea of gasifying the municipal waste, producing syngas serving as fuel for the trigeneration system. Such advanced system when improved is thus self-sustainable without dependency on net grid, district heating and district...

  18. Preparation of one-step NiO/Ni-CGO composites using factorial design

    International Nuclear Information System (INIS)

    Araujo, A.J.M. de; Sousa, A R.O. de; Camposa, L.F.A.; Macedo, D.A.; Loureiro, F. J.A.; Fagg, D.P.

    2016-01-01

    This work deals with the synthesis, processing and characterization of NiO/Ni- CGO composite materials as potential solid oxide fuel cell (SOFC) anodes. The particulate materials were obtained by a one-step synthesis method and characterized by thermal analysis (prior to calcination) and X-ray diffraction (calcined powder). The ceramic processing of samples containing from 30 to 70 wt.% NiO was carried out by factorial design. Besides the NiO content controlled during the chemical synthesis, the impacts of the pore-former content (citric acid, used in proportions of 0, 7.5 and 15 wt.%) and the sintering temperature (1300, 1350 and 1400 °C) were also investigated. The open porosity of NiO-CGO composites and reduced Ni-CGO cermets was modeled as a function of factors (NiO content, citric acid content and sintering temperature) and interaction of factors. (author)

  19. A Ba-free sealing glass with a high CTE and excellent interface stability optimized for SOFC/SOEC stack applications

    DEFF Research Database (Denmark)

    Ritucci, Ilaria; Agersted, Karsten; Zielke, Philipp

    2017-01-01

    -mechanical properties and compositional variations are reviewed and discussed by thermal analyses and in situ XRD, in order to design and optimize the sealing profile and reduce the residual porosity. The glass after heat treatment partially devitrifies into augite and nepheline with residual glass phase of around 64...

  20. Bonding characteristics of glass seal/metallic interconnect for SOFC applications: Comparative study on chemical and mechanical properties of the interface

    DEFF Research Database (Denmark)

    Abdoli, Hamid; Alizadeh, Parvin; Boccaccini, Dino

    fracture energies is double cantilever beam (DCB) test. The method allows to measure the crack-growth resistance of these materials to be able to use fracture mechanics design methods. Stable crack growth is necessary to get reliable and unambiguous fracture toughness data. If the fracture toughness values...

  1. Designing Communication Design

    DEFF Research Database (Denmark)

    Løvlie, Anders Sundnes

    2016-01-01

    Innovating in the field of new media genres requires methods for producing designs that can succeed in being disseminated and used outside of design research labs. This article uses the author's experiences with the development of university courses in communication design to address the research...... question: How can we design courses to give students the competencies they need to work as designers of new media? Based on existing approaches from UX design and other fields, I present a model that has demonstrated its usefulness in the development of commercial products and services. The model...

  2. Simulation of the steady-state behaviour of a new design of a single planar Solid Oxide Fuel Cell

    Directory of Open Access Journals (Sweden)

    Pianko-Oprych Paulina

    2016-03-01

    Full Text Available The aim of the work was to develop a mathematical model for computing the steady-state voltage – current characteristics of a planar Solid Oxide Fuel Cell and to determine the performance of a new SOFC design. The design involves cross-flow bipolar plates. Each of the bipolar plates has an air channel system on one side and a fuel channel system on the other side. The proposed model was developed using the ANSYS-Fluent commercial Computational Fluid Dynamics (CFD software supported by additional Fuel Cell module. The results confirm that the model can well simulate the diagonal current path. The effects of temperature and gas flow through the channels and a Membrane Electrode Assembly (MEA structure were taken into account. It was shown that a significant increase of the MEA temperature at high current density can lead to hot spots formation and hence electrode damage.

  3. A novel design of anode-supported solid oxide fuel cells with Y 2O 3-doped Bi 2O 3, LaGaO 3 and La-doped CeO 2 trilayer electrolyte

    Science.gov (United States)

    Guo, Weimin; Liu, Jiang

    Anode-supported solid oxide fuel cells (SOFCs) with a trilayered yttria-doped bismuth oxide (YDB), strontium- and magnesium-doped lanthanum gallate (LSGM) and lanthanum-doped ceria (LDC) composite electrolyte film are developed. The cell with a YDB (18 μm)/LSGM (19 μm)/LDC (13 μm) composite electrolyte film (designated as cell-A) shows the open-circuit voltages (OCVs) slightly higher than that of a cell with an LSGM (31 μm)/LDC (17 μm) electrolyte film (designated as cell-B) in the operating temperature range of 500-700 °C. The cell-A using Ag-YDB composition as cathode exhibits lower polarization resistance and ohmic resistance than those of a cell-B at 700 °C. The results show that the introduction of YDB to an anode-supported SOFC with a LSGM/LDC composite electrolyte film can effectively block electronic transport through the cell and thus increased the OCVs, and can help the cell to achieve higher power output.

  4. Design, Construction and Operation of a Molten Carbonate Fuel Cell (MCFC) in the 100-kW-Class

    International Nuclear Information System (INIS)

    Heiming, Andreas; Huppmann, Gerhard; Aasberg-Petersen, Kim

    1999-01-01

    In fuel cells, the electrochemical energy of the fuel is converted directly into electricity and heat. The electrochemical conversion is inherently related to high electrical efficiencies and very low pollutant emissions. Fuel cells with sufficiently high operating temperatures such as (1) the phosphoric acid fuel cell (PAFC), operating temperature: 200 o C, (2) the molten carbonate fuel cell (MCFC), operating temperature: 650 o C and (3) the solid oxide fuel cell (SOFC), operating temperature: around 900 o C are best suited for decentralised combined heat and power (CHP) applications. This is due to the fact, that the heat of the exothermic reaction taking place in the fuel cell can be used in the domestic, commercial and industrial sector for heating and hot water or steam production. At the present time, gas-engines or gas-turbines are the preferred CHP-technologies for these applications. Nowadays, the PAFC is commercially available. More than 160 plants, each with a power of 200 kW, have been installed world-wide. Ruhrgas has investigated the behaviour of a 200 kW PAFC at its research centre in Dorsten, Germany, and at the site of a local utility. High temperature fuel cells such as MCFC or SOFC promise electrical efficiencies above 50 % in simple cycle mode. Up to now, MCFC-test plants have been built and operated in the 100 kW to 1 MW power range. The largest MCFC ever operated consisted of 16 identical stacks of 125 kW each, resulting in a plant power of 2 MW. The initial experience with SOFC in this power-range is currently gained from the operation of a 100 kW plant. In this paper, the result of the construction and operation of a highly innovatively designed 280 kW MCFC will be presented. This plant has been designed, built and operated by a European consortium for the development and market introduction of the MCFC. Members of the consortium are MTU-Friedrichshafen GmbH, Haldor Topsoee NS, Elkraft A.m.b.H., RWE Energie AG and Ruhrgas AG. (author)

  5. Synthesis and characterization of the double perovskite BaSrCoFe{sub 1}-{sub x}Ni{sub x}O{sub 5.5} like cathode for solid oxide fuel cells; Sintesis y caracterizacion de la doble perovskita BaSrCoFe{sub 1}-{sub x}Ni{sub x}O{sub 5.5} como catodo para celdas SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado F, J.; Avalos R, L.; Viramontes G, G. [Universidad Michoacana de San Nicolas de Hidalgo, Facultad de Ingenieria Electrica, Santiago Tapia 403, Morelia 58030, Michoacan (Mexico); Reyes R, A. [Centro de Investigacion en Materiales Avanzados, Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua 31109, Chihuahua (Mexico)

    2013-08-01

    Have been synthesized via sol-gel method and characterized by X-ray diffraction, electrical conductivity and thermal expansion coefficient, new material composites BaSrCoFe{sub 1{sub x}}Ni{sub x}O{sub 5.5} (double perovskite type) with the addition of Ni in solid solution Ni{sub x} (x = 0.025, 0.05, 0.075, 0.1 and 0.2), as alternative cathodes for solid oxide fuel cells of intermediate temperature (Sofc-It). X-ray diffraction confirmed the formation of the tetragonal structure perovskite phase BaSrCoFe{sub 1}-{sub x}Ni{sub x}O{sub 5.5}, with the presence of small peaks identified in 2{theta} values below 30 degrees as BaCO{sub 3} and CoFe{sub 2}O{sub 4}. The electrical conductivity increases with the temperature between 350-470 degrees C and then decreases due to the loss of oxygen in the net, which causes differences in conductivity. Semiconductor behavior was obtained in all compositions. Thermal expansion coefficient determination, showed a linear dependence inversely proportional to the concentration of Ni. Our results of electrical conductivity and thermal expansion coefficient, reach to the conclusion that the cathodes between 0.1 and 0.2 Ni, have the greatest possibility for application in Sofc-It. (Author)

  6. Efecto sobre la reacción de oxígeno de la forma y la microestructura del contacto electrodo-electrolito de electrodos a difusión interna en Celdas de Combustible de Óxido Sólido (SOFC

    Directory of Open Access Journals (Sweden)

    Jiménez, R.

    1999-12-01

    Full Text Available In this work we have studied the elemental electrode shape and electrode - electrolyte contact microstructure influence of Internal diffusion (ID gas electrode in solid oxide fuel cells (SOFC. First the influence over the electrolyte effective resistance is studied. Then the influence of the shape of the elemental contact grain of ID electrode is also studied. Finally the influence of the electrode - electrolyte contact microstructure in the electrode response for a pure diffuse control is modelled. From the obtained results, conclusions on the contact microstructure and electrode shape influence over the oxygen reaction of this kind of gas electrodes are commented.

    En este trabajo, se estudia la influencia de la forma del electrodo elemental y la microestructura del contacto electrodo-electrolito, del electrodo de gas a difusión interna en celdas de combustible de óxido sólido (SOFC. Se determina la influencia de la microestructura del contacto electrodo electrolito sobre la resistencia efectiva del electrolito, la influencia de la forma del contacto de un grano elemental de un electrodo poroso suponiendo que sea aproximadamente una semiesfera sobre la reacción del electrodo y finalmente la influencia de la microestructura del contacto electrodo - electrolito en la respuesta a un control difusivo puro del electrodo. De los resultados obtenidos se pueden extraer conclusiones sobre la influencia de la microestructura del contacto y forma del electrodo en la reacción de oxígeno en este tipo de electrodos de gas.

  7. Sc and Nb Dopants in SrCoO3 Modulate Electronic and Vacancy Structures for Improved Water Splitting and SOFC Cathodes

    KAUST Repository

    Tahini, Hassan A.

    2017-01-12

    SrCoO3 is a promising material in the field of electrocatalysis. Difficulties in synthesising the material in its cubic phase have been overcome by doping it with Sc and Nb ions [Mater. Horiz.2015, 2, 495–501]. Using ab initio calculations and special quasi random structures we undertake a systematic study of these dopants in order to elucidate the effect of doping on electronic structure of the SrCoO3 host and the formation of oxygen vacancies. We find that while the overall electronic structure of SrCoO3 is preserved, increasing the Sc fraction leads to a decrease of electrical conductivity, in agreement with earlier experimental work. For low Sc and Nb doping fractions we find that the oxygen vacancy formation increases relative to undoped SrCoO3. However, as the dopants concentration is increased the vacancy formation energy drops significantly, indicating a strong tendency to accommodate high concentration of oxygen vacancies and hence non-stoichiometry. This is explained based on the electronic instabilities caused by the presence of Sc ions which weakens the B-O interactions as well as the increased degree of electron delocalization on the oxygen sublattice. Sc dopants also shift the p-band centre closer to the Fermi level, which can be associated with experimentally reported improvements in oxygen evolution reactions. These findings provide crucial baseline information for the design of better electrocatalysts for oxygen evolution reactions as well as fuel-cell cathode materials.

  8. Sc and Nb Dopants in SrCoO3 Modulate Electronic and Vacancy Structures for Improved Water Splitting and SOFC Cathodes

    KAUST Repository

    Tahini, Hassan A.; Tan, Xin; Zhou, Wei; Zhu, Zhonghua; Schwingenschlö gl, Udo; Smith, Sean C.

    2017-01-01

    SrCoO3 is a promising material in the field of electrocatalysis. Difficulties in synthesising the material in its cubic phase have been overcome by doping it with Sc and Nb ions [Mater. Horiz.2015, 2, 495–501]. Using ab initio calculations and special quasi random structures we undertake a systematic study of these dopants in order to elucidate the effect of doping on electronic structure of the SrCoO3 host and the formation of oxygen vacancies. We find that while the overall electronic structure of SrCoO3 is preserved, increasing the Sc fraction leads to a decrease of electrical conductivity, in agreement with earlier experimental work. For low Sc and Nb doping fractions we find that the oxygen vacancy formation increases relative to undoped SrCoO3. However, as the dopants concentration is increased the vacancy formation energy drops significantly, indicating a strong tendency to accommodate high concentration of oxygen vacancies and hence non-stoichiometry. This is explained based on the electronic instabilities caused by the presence of Sc ions which weakens the B-O interactions as well as the increased degree of electron delocalization on the oxygen sublattice. Sc dopants also shift the p-band centre closer to the Fermi level, which can be associated with experimentally reported improvements in oxygen evolution reactions. These findings provide crucial baseline information for the design of better electrocatalysts for oxygen evolution reactions as well as fuel-cell cathode materials.

  9. Prompting Designers to Design

    DEFF Research Database (Denmark)

    Ahmed, Saeema

    2006-01-01

    Recent research suggest that engineering designers need assistance to understand what information is relevant for their particular design problem. They require guidance in formulating their queries and also to understand what information is relevant for them. This paper presents an approach to pr...

  10. Design and analysis of a waste gasification energy system with solid oxide fuel cells and absorption chillers

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2018-01-01

    Energy saving is an open point in most European countries where energy policies are oriented to reduce the use of fossil fuels, greenhouses emissions and energy independence, and to increase the use of renewable energies. In the last several years, new technologies have been developed and some...... of them received subsidies to increase installation and reduce cost. This article presents a new sustainable trigeneration system (power, heat and cool) based on a solid oxide fuel cell (SOFC) system integrated with an absorption chiller for special applications such as hotels, resorts, hospitals, etc....... with a focus on plant design and performance. The proposal system is based on the idea of gasifying the municipal waste, producing syngas serving as fuel for the trigeneration system. Such advanced system when improved is thus self-sustainable without dependency on net grid, district heating and district...

  11. A conceptual design of catalytic gasification fuel cell hybrid power plant with oxygen transfer membrane

    Science.gov (United States)

    Shi, Wangying; Han, Minfang

    2017-09-01

    A hybrid power generation system integrating catalytic gasification, solid oxide fuel cell (SOFC), oxygen transfer membrane (OTM) and gas turbine (GT) is established and system energy analysis is performed. In this work, the catalytic gasifier uses steam, recycled anode off-gas and pure oxygen from OTM system to gasify coal, and heated by hot cathode off-gas at the same time. A zero-dimension SOFC model is applied and verified by fitting experimental data. Thermodynamic analysis is performed to investigate the integrated system performance, and system sensitivities on anode off-gas back flow ratio, SOFC fuel utilization, temperature and pressure are discussed. Main conclusions are as follows: (1) System overall electricity efficiency reaches 60.7%(HHV) while the gasifier operates at 700 °C and SOFC at 850 °C with system pressure at 3.04 bar; (2) oxygen enriched combustion simplify the carbon-dioxide capture process, which derives CO2 of 99.2% purity, but results in a penalty of 6.7% on system electricity efficiency; (3) with SOFC fuel utilization or temperature increasing, the power output of SOFC increases while GT power output decreases, and increasing system pressure can improve both the performance of SOFC and GT.

  12. Winged design; Befluegeltes Design

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Tilman

    2013-10-15

    Today the wind rotor blades are about 80 meter long. To keep them light and transportable designers and material scientists come up with a number of ideas. Will the carbon fiber prevail against the glass fiber? [German] Ueber 80 Meter messen die laengsten Rotorblaetter heute. Um sie leicht und transportfaehig zu halten, lassen sich Designer und Materialforscher einiges einfallen. Wird sich die Kohlefaser gegen die Glasfaser durchsetzen?.

  13. Dansk Design

    DEFF Research Database (Denmark)

    Dickson, Thomas

    Indhold: Hvad er design?; Hvor kommer dansk design fra?; Produktdesign; Tekstil- og tøjdesign; Design af møbler og boligindretning; Bygningen og design; Arbejdets design; Transportdesign; Offentligt design; Grafisk design; Nye tider og en ny slags design...

  14. Application of impedance spectroscopy to SOFC research

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, G.; Mason, T.O. [Northwestern Univ., Evanston, IL (United States); Pederson, L.R. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-12-31

    With the resurgence of interest in solid oxide fuel cells and other solid state electrochemical devices, techniques originally developed for characterizing aqueous systems are being adapted and applied to solid state systems. One of these techniques, three-electrode impedance spectroscopy, is particularly powerful as it allows characterization of subcomponent and interfacial properties. Obtaining accurate impedance spectra, however, is difficult as reference electrode impedance is usually non-negligible and solid electrolytes typically have much lower conductance than aqueous solutions. Faidi et al and Chechirlian et al have both identified problems associated with low conductivity media. Other sources of error are still being uncovered. Ford et al identified resistive contacts with large time constants as a possibility, while Me et al showed that the small contact capacitance of the reference electrode was at fault. Still others show that instrument limitations play a role. Using the voltage divider concept, a simplified model that demonstrates the interplay of these various factors, predicts the form of possible distortions, and offers means to minimize errors is presented.

  15. Compliant Glass Seals for SOFC Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Yeong -Shyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Choi, Jung-Pyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephens, Elizabeth V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Koeppel, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stevenson, Jeffry W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lara-Curzio, Edgar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-04-30

    This report summarizes results from experimental and modeling studies performed by participants in the Solid-State Energy Conversion Alliance (SECA) Core Technology Program, which indicate that compliant glass-based seals offer a number of potential advantages over conventional seals based on de-vitrifying glasses, including reduced stresses during stack operation and thermal cycling, and the ability to heal micro-damage induced during thermal cycling. The properties and composition of glasses developed and/or investigated in these studies are reported, along with results from long-term (up to 5,800h) evaluations of seals based on a compliant glass containing ceramic particles or ceramic fibers.

  16. Pattern Electrodes for Studying SOFC Electrochemistry

    NARCIS (Netherlands)

    Patel, H.C.; Biradar, N.; Venkataraman, V.; Aravind, P.V.

    2013-01-01

    Pattern anodes can be used to localize reactions and study individual processes like charge transfer, adsorption, diffusion etc. Ceria and Nickel (Ni) pattern anodes were fabricated with the same dimensions with Triple phase boundary (TPB) lengths of 0.2707 m/cm2. Electrochemical Impedance

  17. Detailed Electrochemical Characterisation of Large SOFC Stacks

    DEFF Research Database (Denmark)

    Mosbæk, Rasmus Rode; Hjelm, Johan; Barfod, R.

    2012-01-01

    application of advanced methods for detailed electrochemical characterisation during operation. An operating stack is subject to steep compositional gradients in the gaseous reactant streams, and significant temperature gradients across each cell and across the stack, which makes it a complex system...... Fuel Cell A/S was characterised in detail using electrochemical impedance spectroscopy. An investigation of the optimal geometrical placement of the current probes and voltage probes was carried out in order to minimise measurement errors caused by stray impedances. Unwanted stray impedances...... are particularly problematic at high frequencies. Stray impedances may be caused by mutual inductance and stray capacitance in the geometrical set-up and do not describe the fuel cell. Three different stack geometries were investigated by electrochemical impedance spectroscopy. Impedance measurements were carried...

  18. Electrochemical Impedance Studies of SOFC Cathodes

    DEFF Research Database (Denmark)

    Hjelm, Johan; Søgaard, Martin; Wandel, Marie

    2007-01-01

    Mixed ion- and electron-conducting composite electrodes consisting of doped ceria and perovskite have been studied by electrochemical impedance spectroscopy (EIS) at different temperatures and oxygen partial pressures. This paper aims to describe the different contributions to the polarisation...

  19. Flexible ceramic gasket for SOFC generator

    Science.gov (United States)

    Zafred, Paolo [Murrysville, PA; Prevish, Thomas [Trafford, PA

    2009-02-03

    A solid oxide fuel cell generator (10) contains stacks of hollow axially elongated fuel cells (36) having an open top end (37), an oxidant inlet plenum (52), a feed fuel plenum (11), a combustion chamber (94) for combusting reacted oxidant/spent fuel; and, optionally, a fuel recirculation chamber (106) below the combustion chamber (94), where the fuel recirculation chamber (94) is in part defined by semi-porous fuel cell positioning gasket (108), all within an outer generator enclosure (8), wherein the fuel cell gasket (108) has a laminate structure comprising at least a compliant fibrous mat support layer and a strong, yet flexible woven layer, which may contain catalytic particles facing the combustion chamber, where the catalyst, if used, is effective to further oxidize exhaust fuel and protect the open top end (37) of the fuel cells.

  20. Study on AN Intermediate Temperature Planar Sofc

    Science.gov (United States)

    Wang, Shaorong; Cao, Jiadi; Chen, Wenxia; Lu, Zhiyi; Wang, Daqian; Wen, Ting-Lian

    An ITSOFC consisted of Ni/YSZ anode supported YSZ composite thin film and La0.6Sr0.4CoO3 (LSCO) cathode combined with a Ce0.8Sm0.2O1.9 (CSO) interlayer was studied. Tape cast method was applied to prepare green sheets of Ni/YSZ anode supported YSZ composite thin film. After isostatic pressing and cosintering, the YSZ film on the Ni/YSZ anode was gas-tight dense, and 15-30μm thick. The area of the composite film was over 100 cm2. A CSO interlayer was sintered on to the YSZ electrolyte film to protect LSCO cathode from reaction with YSZ at high temperatures. The LSCO cathode layer was screen printed onto the CSO interlayer and sintered at 1200°C for 3h to form a single cell. The obtained single cell was operated with H2 as fuel and O2 as oxidant. The cell performance and impedance were measured and discussed relating with the component contributions.

  1. SOFC seal and cell thermal management

    Science.gov (United States)

    Potnis, Shailesh Vijay [Neenah, WI; Rehg, Timothy Joseph [Huntington Beach, CA

    2011-05-17

    The solid oxide fuel cell module includes a manifold, a plate, a cathode electrode, a fuel cell and an anode electrode. The manifold includes an air or oxygen inlet in communication with divergent passages above the periphery of the cell which combine to flow the air or oxygen radially or inwardly for reception in the center of the cathode flow field. The latter has interconnects providing circuitous cooling passages in a generally radial outward direction cooling the fuel cell and which interconnects are formed of different thermal conductivity materials for a preferential cooling.

  2. A novel design of anode-supported solid oxide fuel cells with Y{sub 2}O{sub 3}-doped Bi{sub 2}O{sub 3}, LaGaO{sub 3} and La-doped CeO{sub 2} trilayer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Weimin [School of Chemistry and Engineering, South China University of Technology, The Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, Guangzhou 510640 (China); Department of Biological and Chemical Engineering, Guangxi University of Technology, Liuzhou 545006 (China); Liu, Jiang [School of Chemistry and Engineering, South China University of Technology, The Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, Guangzhou 510640 (China)

    2010-12-15

    Anode-supported solid oxide fuel cells (SOFCs) with a trilayered yttria-doped bismuth oxide (YDB), strontium- and magnesium-doped lanthanum gallate (LSGM) and lanthanum-doped ceria (LDC) composite electrolyte film are developed. The cell with a YDB (18 {mu}m)/LSGM (19 {mu}m)/LDC (13 {mu}m) composite electrolyte film (designated as cell-A) shows the open-circuit voltages (OCVs) slightly higher than that of a cell with an LSGM (31 {mu}m)/LDC (17 {mu}m) electrolyte film (designated as cell-B) in the operating temperature range of 500-700 C. The cell-A using Ag-YDB composition as cathode exhibits lower polarization resistance and ohmic resistance than those of a cell-B at 700 C. The results show that the introduction of YDB to an anode-supported SOFC with a LSGM/LDC composite electrolyte film can effectively block electronic transport through the cell and thus increased the OCVs, and can help the cell to achieve higher power output. (author)

  3. VLSI design

    CERN Document Server

    Chandrasetty, Vikram Arkalgud

    2011-01-01

    This book provides insight into the practical design of VLSI circuits. It is aimed at novice VLSI designers and other enthusiasts who would like to understand VLSI design flows. Coverage includes key concepts in CMOS digital design, design of DSP and communication blocks on FPGAs, ASIC front end and physical design, and analog and mixed signal design. The approach is designed to focus on practical implementation of key elements of the VLSI design process, in order to make the topic accessible to novices. The design concepts are demonstrated using software from Mathworks, Xilinx, Mentor Graphic

  4. Control loop design and control performance study on direct internal reforming solid oxide fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.; Weng, S.; Su, M. [Key Laboratory of Power Machinery and Engineering of the Education Ministry, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2009-10-15

    A solid oxide fuel cell (SOFC) stack is a complicated nonlinear power system. Its system model includes a set of partial differential equations that describe species, mass, momentum and energy conservation, as well as the electrochemical reaction models. The validation and verification of the control system by experiment is very expensive and difficult. Based on the distributed and lumped model of a one-dimensional SOFC, the dynamic performance with different control loops for SOFC is investigated. The simulation result proves that the control system is appropriate and feasible, and can effectively satisfy the requirement of variable load power demand. This simulation model not only can prevent some latent dangers of the fuel cell system but also predict the distributed parameters' characteristics inside the SOFC system. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  5. Design Anthropology in Participatory Design

    DEFF Research Database (Denmark)

    Smith, Rachel Charlotte; Kjærsgaard, Mette Gislev

    2015-01-01

    This focus section explores the opportunities of design anthropology in participatory design as an approach to research and design in an increasingly global and digital world. Traditionally, ethnography has been used in Participatory design to research real-life contexts and challenges, and as ways...... opportunities of using design anthropology as a holistic and critical approach to addressing societal challenges and change, and a way for anthropologists and designers to engage in participatory research and design that extend beyond the empirical....

  6. Design Anthropology in Participatory Design

    DEFF Research Database (Denmark)

    Smith, Rachel Charlotte; Gislev Kjærsgaard, Mette

    2014-01-01

    In this workshop we explore the opportunities of ethnography and design anthropology in Participatory Design (PD) as an approach to design in an increasingly global and digital world. Traditionally, ethnography has been used in PD to research real-life contexts and challenges, and as ways...... opportunities of using design anthropology as a holistic and critical approach to societal challenges, and a way for anthropologists and designers to engage in design that extends beyond the empirical....

  7. Evidensbaseret design

    DEFF Research Database (Denmark)

    Pagh, Jesper

    2013-01-01

    Debatindlæg om evidensbaseret design, som argumenterer for at det dels er en gammeldags, modernistisk tilgang til design, dels ikke baserer sig på evidens.......Debatindlæg om evidensbaseret design, som argumenterer for at det dels er en gammeldags, modernistisk tilgang til design, dels ikke baserer sig på evidens....

  8. FPGA design

    CERN Document Server

    Simpson, Philip

    2010-01-01

    This book describes best practices for successful FPGA design. It is the result of the author's meetings with hundreds of customers on the challenges facing each of their FPGA design teams. By gaining an understanding into their design environments, processes, what works and what does not work, key areas of concern in implementing system designs have been identified and a recommended design methodology to overcome these challenges has been developed. This book's content has a strong focus on design teams that are spread across sites. The goal being to increase the productivity of FPGA design t

  9. Design Games

    DEFF Research Database (Denmark)

    Johansson, Martin Wetterstrand

    2007-01-01

    In this paper design games are discussed as an approach to managing design sessions. The focus is on the collaborative design session and more particular on how to set up the collaboration and reinsure progress. Design games have the advantage of framing the collaborative assignment at hand....... Experiments can be set up to explore possible futures and design games has the qualities of elegantly focus the work at the same time as it lessens the burden for the process facilitator. The present paper goes into detail about how design games can be set up to facilitate collaboration and how the design...

  10. Design What?%

    DEFF Research Database (Denmark)

    Engholm, Ida

    2017-01-01

    processes, which require specific development methods across a wide range of disciplines, from industrial design over graphic communication to service and digital design and strategic corporate development. The book addresses both established methods and recent research in design processes at leading design...... idea to the end-result. The goal for this graphic non-fiction project is to document and present both historical and current developments in design methodology, from the early attempts at documenting procedures for design process management at the Bauhaus School in the 1920s to contemporary design...

  11. VLSI design

    CERN Document Server

    Basu, D K

    2014-01-01

    Very Large Scale Integrated Circuits (VLSI) design has moved from costly curiosity to an everyday necessity, especially with the proliferated applications of embedded computing devices in communications, entertainment and household gadgets. As a result, more and more knowledge on various aspects of VLSI design technologies is becoming a necessity for the engineering/technology students of various disciplines. With this goal in mind the course material of this book has been designed to cover the various fundamental aspects of VLSI design, like Categorization and comparison between various technologies used for VLSI design Basic fabrication processes involved in VLSI design Design of MOS, CMOS and Bi CMOS circuits used in VLSI Structured design of VLSI Introduction to VHDL for VLSI design Automated design for placement and routing of VLSI systems VLSI testing and testability The various topics of the book have been discussed lucidly with analysis, when required, examples, figures and adequate analytical and the...

  12. Design Accountability

    DEFF Research Database (Denmark)

    Koskinen, Ilpo; Krogh, Peter

    2015-01-01

    When design research builds on design practice, it may contribute to both theory and practice of design in ways richer than research that treats design as a topic. Such research, however, faces several tensions that it has to negotiate successfully in order not to lose its character as research....... This paper looks at constructive design research which takes the entanglement of theory and practice as its hallmark, and uses it as a test case in exploring how design researchers can work with theory, methodology, and practice without losing their identity as design researchers. The crux of practice based...... design research is that where classical research is interested in singling out a particular aspect and exploring it in depth, design practice is characterized by balancing numerous concerns in a heterogenous and occasionally paradoxical product. It is on this basis the notion of design accountability...

  13. Mechanical design

    CERN Document Server

    Risitano, Antonino

    2011-01-01

    METHODOLOGICAL STATEMENT OF ENGINEERING DESIGNApproaches to product design and developmentMechanical design and environmental requirementsPROPERTIES OF ENGINEERING MATERIALSMaterials for mechanical designCharacterization of metalsStress conditionsFatigue of materialsOptimum material selection in mechanical designDESIGN OF MECHANICAL COMPONENTS AND SYSTEMSFailure theoriesHertz theoryLubrificationShafts and bearingsSplines and keysSpringsFlexible machine elementsSpur gearsPress and shrink fitsPressure tubesCouplingsClutchesBrakes

  14. Memory design

    DEFF Research Database (Denmark)

    Tanderup, Sisse

    by cultural forms, often specifically by the concept of memory in philosophy, sociology and psychology, while Danish design traditionally has been focusing on form and function with frequent references to the forms of nature. Alessi's motivation for investigating the concept of memory is that it adds......Mind and Matter - Nordik 2009 Conference for Art Historians Design Matters Contributed Memory design BACKGROUND My research concerns the use of memory categories in the designs by the companies Alessi and Georg Jensen. When Alessi's designers create their products, they are usually inspired...... a cultural dimension to the design objects, enabling the objects to make an identity-forming impact. Whether or not the concept of memory plays a significant role in Danish design has not yet been elucidated fully. TERMINOLOGY The concept of "memory design" refers to the idea that design carries...

  15. Business design or Creative design

    DEFF Research Database (Denmark)

    Sørensen, Suna; Lassen, Astrid Heidemann; Nielsen, Louise Møller

    2008-01-01

    Business design is about turning good ideas into future business, but it requires a great entrepreneurial opportunity to be exploited via a valid strategic and organizational design. The literature says much about how entrepreneurs design strategies and organizations, but how do they design...

  16. Designing Interfaces

    CERN Document Server

    Tidwell, Jenifer

    2010-01-01

    Despite all of the UI toolkits available today, it's still not easy to design good application interfaces. This bestselling book is one of the few reliable sources to help you navigate through the maze of design options. By capturing UI best practices and reusable ideas as design patterns, Designing Interfaces provides solutions to common design problems that you can tailor to the situation at hand. This updated edition includes patterns for mobile apps and social media, as well as web applications and desktop software. Each pattern contains full-color examples and practical design advice th

  17. Design and development of a diesel and JP-8 logistic fuel processor

    Science.gov (United States)

    Roychoudhury, Subir; Lyubovsky, Maxim; Walsh, D.; Chu, Deryn; Kallio, Erik

    The paper describes the design and performance of a breadboard prototype for a 5 kW fuel-processor for powering a solid oxide fuel cell (SOFC) stack. The system was based on a small, modular catalytic Microlith auto-thermal (ATR) reactor with the versatility of operating on diesel, Jet-A or JP-8 fuels. The reforming reactor utilized Microlith substrates and catalyst technology (patented and trademarked). These reactors have demonstrated the capability of efficiently reforming liquid and gaseous hydrocarbon fuels at exceptionally high power densities. The performance characteristics of the auto-thermal reactor (ATR) have been presented along with durability data. The fuel processor integrates fuel preparation, steam generation, sulfur removal, pumps, blowers and controls. The system design was developed via ASPEN ® Engineering Suite process simulation software and was analyzed with reference to system balance requirements. Since the fuel processor has not been integrated with a fuel cell, aspects of thermal integration with the stack have not been specifically addressed.

  18. Design Anthropology

    DEFF Research Database (Denmark)

    Gunn, Wendy

    Design anthropology is a call for a different way of involving anthropology and participatory observation within practices of designing technologies, services, policies and infrastructure that does not aim towards changing human behavior. Here design is considered the process and not the object...... of inquiry. The paper presents a short history of design anthropology, its theoretical underpinnings and methodologies. Theoretically, the emerging field is influenced by processual, critical and action orientated approaches in anthropology. I argue that by combining anthropological methodology and knowledge...... with the future orientated imaginative praxis of design skill and collaborative design processes, anthropology and design could learn from each other. I conclude by referring to what theories, methods, and approaches are in use by practitioners of design anthropology....

  19. Danish design

    DEFF Research Database (Denmark)

    Dickson, Thomas

    2001-01-01

    Hvordan dansk design bliver innovativt og verdensberømt igen som i storhedstiden i 1950- og 60'erne......Hvordan dansk design bliver innovativt og verdensberømt igen som i storhedstiden i 1950- og 60'erne...

  20. Designing motivation

    DEFF Research Database (Denmark)

    How can products be designed to change our habits for the better? What is some of the leading research that designers can draw on to create new systems that motivate people towards healthier behaviour? Designing Motivation is an edited collection of ‘industrialist cheat sheets’: 22 single......-page summaries of research articles relating to technology design, motivation, and behaviour change. Ranging across the fields of economics, sociology, design research and behavioural science, each summary draws out the design implications of the research. It is intended as a resource for designers who...... are grappling with how to create motivating products, and as a primer for students who want a brief introduction to some of the relevant theories, findings and design interventions in these fields. The editor's introduction raises a number of issues encountered when we try to apply behavioural research...

  1. Research Design

    DEFF Research Database (Denmark)

    2019-01-01

    Gunnar Scott Reinbacher (editor) Antology.  Research Design : Validation in Social Sciences. Gunnar Scott Reinbacher: Introduction. Research design and validity. 15p Ole Riis: Creative Research design. 16 p Lennart Nørreklit: Validity in Research Design. 24p Gitte Sommer Harrits: Praxeological...... Scott Reinbacher: Multidisciplinary Research Designs in Problem Based Research. The case of an european project on chronical diseases, the Tandem project (Training Alternmative Networking Skills in Diabetes Management). 15p Niels Nørgaard Kristensen: A qualitative bottom up approach to post modern...... knowledge: An integrated strategy for combining "explaining" and "understanding". 22p Heidi Houlberg Salomonsen & Viola Burau: Comparative research designs. 40p Rasmus Antoft & Heidi Houlberg Salomonsen: Studying organizations by a Pragmatic Research Design: the case of qualitative case study  designs. 31p...

  2. Repository design

    Energy Technology Data Exchange (ETDEWEB)

    John, C M

    1982-01-01

    Various technical issues of radioactive waste design are addressed in this paper. Two approaches to repository design considered herein are: (1) design to minimize the disturbance of the hot rock; and (2) designs that intentionally modify the hot rock to insure better containment of the wastes. The latter designs range from construction of a highly impermeable barrier around a spherical cavern to creating a matrix of tunnels and boreholes to form a cage within which the hydraulic pressure is nearly constant. Examples of these design alternatives are described in some detail. It is concluded that proposed designs for repositories illustrate that performance criteria considered acceptable for such facilities can be met by appropriate site selection and repository engineering. With these technically feasible design concepts, it is also felt that socioeconomic and institutional issues can be better resolved. (BLM)

  3. Breakwater design

    OpenAIRE

    Verhagen, H.J.; van den Bos, J.P.

    2017-01-01

    For this book we have deliberately chosen that the text should follow a more or less logical design procedure for breakwaters. It follows the required design steps from the system level down to the individual crosssection level, and in time from conceptual design to construction. This systematic approach starts at the functional description of breakwaters, system analysis including side-effects and derivation of boundary conditions and continues to the actual design, first of the main armour ...

  4. Design typology and design organisation

    DEFF Research Database (Denmark)

    Andreasen, Mogens Myrup; Wognum, N.; McAloone, Timothy Charles

    2002-01-01

    research society has recognised normative procedural models of designing as being a reasonable answer to the question: How do designing proceed? The reasoning behind the models, from which the design methodology model by [Pahl & Beitz 1995], may be seen as a characteristic one, was a mix of human problem......The idea of focusing upon the creation of a design typology was articulated by [Andreasen & Wognum 2000] and detailed by [Andreasen & Wognum 2001]. The aim was to propose a typology, which could serve as identification of design types and design research contributions. For a long period the design...... solving-, design management-, and artefact nature-reasoning. Critique has been raised to that type of models as being neither explanatory nor instructive. If we accept these models as merely being pragmatically "stepping-stone" explanations of what happens during designing, it is interesting to observe...

  5. Design Processes

    DEFF Research Database (Denmark)

    Ovesen, Nis

    2009-01-01

    Inspiration for most research and optimisations on design processes still seem to focus within the narrow field of the traditional design practise. The focus in this study turns to associated businesses of the design professions in order to learn from their development processes. Through interviews...... and emerging production methods....

  6. Radiopharmacy design

    International Nuclear Information System (INIS)

    Lazarus, C.R.

    1985-01-01

    The factors which should be considered when designing a radiopharmacy are examined. These include the levels and types of radioactivity and the functions, location, size and layout of the radiopharmacy. Aspects of the design process including environmental cleanliness in enclosed spaces and microbiological safety cabinets are also discussed. Finally the current publications available on recommendations and guidelines for radiopharmacy designs are briefly reviewed. (UK)

  7. Breakwater design

    NARCIS (Netherlands)

    Verhagen, H.J.; van den Bos, J.P.

    For this book we have deliberately chosen that the text should follow a more or less logical design procedure for breakwaters. It follows the required design steps from the system level down to the individual crosssection level, and in time from conceptual design to construction. This systematic

  8. Design Aspects

    International Nuclear Information System (INIS)

    Hillary, J.J.

    1974-01-01

    Summarizing part of a seminar on iodide filter testing the author classifies the design information on iodine filters which was presented at the meeting in terms of design requirements - species to be trapped sorption materials and engineering factors -, design evaluation, applications and operational experience

  9. Preparation of one-step NiO/Ni-CGO composites using factorial design; Efeitos do processamento e do teor de formador de poros na microestrutura de cermets Ni-CGO

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, A.J.M. de; Sousa, A R.O. de; Camposa, L.F.A.; Macedo, D.A. [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Loureiro, F. J.A.; Fagg, D.P., E-mail: allanjp1993@hotmail.com [Universidade de Aveiro (Portugal)

    2016-07-01

    This work deals with the synthesis, processing and characterization of NiO/Ni- CGO composite materials as potential solid oxide fuel cell (SOFC) anodes. The particulate materials were obtained by a one-step synthesis method and characterized by thermal analysis (prior to calcination) and X-ray diffraction (calcined powder). The ceramic processing of samples containing from 30 to 70 wt.% NiO was carried out by factorial design. Besides the NiO content controlled during the chemical synthesis, the impacts of the pore-former content (citric acid, used in proportions of 0, 7.5 and 15 wt.%) and the sintering temperature (1300, 1350 and 1400 °C) were also investigated. The open porosity of NiO-CGO composites and reduced Ni-CGO cermets was modeled as a function of factors (NiO content, citric acid content and sintering temperature) and interaction of factors. (author)

  10. Design Research

    DEFF Research Database (Denmark)

    Design Research is a new interdisciplinary research area with a social science orientation at its heart, and this book explores how scientific knowledge can be put into practice in ways that are at once ethical, creative, helpful, and extraordinary in their results. In order to clarify the common...... aspects – in terms of features and approaches – that characterize all strands of research disciplines addressing design, Design Research undertakes an in depth exploration of the social processes involved in doing design, as well as analyses of the contexts for design use. The book further elicits...... ‘synergies from interdisciplinary perspectives’ by discussing and elaborating on differing academic perspectives, theoretical backgrounds, and design concept definitions, and evaluating their unique contribution to a general core of design research. This book is an exciting contribution to this little...

  11. Design spaces

    DEFF Research Database (Denmark)

    2005-01-01

    Digital technologies and media are becoming increasingly embodied and entangled in the spaces and places at work and at home. However, our material environment is more than a geometric abstractions of space: it contains familiar places, social arenas for human action. For designers, the integration...... of digital technology with space poses new challenges that call for new approaches. Creative alternatives to traditional systems methodologies are called for when designers use digital media to create new possibilities for action in space. Design Spaces explores how design and media art can provide creative...... alternatives for integrating digital technology with space. Connecting practical design work with conceptual development and theorizing, art with technology, and usesr-centered methods with social sciences, Design Spaces provides a useful research paradigm for designing ubiquitous computing. This book...

  12. Reviews on Solid Oxide Fuel Cell Technology

    Directory of Open Access Journals (Sweden)

    Apinan Soottitantawat

    2009-02-01

    Full Text Available Solid Oxide Fuel Cell (SOFC is one type of high temperature fuel cell that appears to be one of the most promising technology to provide the efficient and clean energy production for wide range of applications (from small units to large scale power plants. This paper reviews the current status and related researches on SOFC technologies. In details, the research trend for the development of SOFC components(i.e. anode, electrolyte, cathode, and interconnect are presented. Later, the current important designs of SOFC (i.e. Seal-less Tubular Design, Segmented Cell in Series Design, Monolithic Design and Flat Plate Design are exampled. In addition, the possible operations of SOFC (i.e. external reforming, indirect internal reforming, and direct internal reforming are discussed. Lastly, the research studies on applications of SOFCs with co-generation (i.e. SOFC with Combined Heat and Power (SOFC-CHP, SOFC with Gas Turbine (SOFC-GT and SOFC with chemical production are given.

  13. Design Research as Conceptual Designing

    DEFF Research Database (Denmark)

    Ylirisku, Salu; Jacucci, Giulio; Sellen, Abigail

    2015-01-01

    define conceptual designing as a constructive framing and re-framing activity, which is mediated by and targeted at the creation of new design concepts. Conceptual designing as an approach is valuable for addressing the fuzziness and ambiguity typical of research that explores novel areas with new...... partners, methods and resources. It is by no means a new phenomenon, and the main contribution of the article is the clarification of conceptual designing as a particular approach to designing and researching. The approach embraces openness, resource-construction and collaboration. We conclude...... that conceptual designing can be especially useful in research and design projects that bring different kinds of people, organizations, technologies and domains together into the forming of new well-founded proposals for development. The presentation of conceptual designing in this paper is written...

  14. ECO DESIGN IN DESIGN PROCESS

    Directory of Open Access Journals (Sweden)

    PRALEA Jeni

    2014-05-01

    Full Text Available Eco-design is a new domain, required by the new trends and existing concerns worldwide, generated by the necessity of adopting new design principles. New design principles require the designer to provide a friendly relationship between concept created, environment and consume. This "friendly" relationship should be valid both at present and in the future, generating new opportunities for product, product components or materials from which it was made. Awareness, by the designer, the importance of this new trend, permits the establishment of concepts that have as their objective the protection of present values and ensuring the legacy of future generations. Ecodesig, by its principles, is involved in the design process, from early stage, the stage of product design. Priority objective of the designers will consist in reducing the negative effects on the environment through the entire life cycle and after it is taken out of use. The main aspects of the eco-design will consider extending product exploitation, make better use of materials, reduction of emission of waste. The design process in the "eco"domein must be started by selecting the function of the concept, materials and technological processes, causing the shape of macro and micro geometric of the product through an analysis that involves optimizing and streamlining the product. This paper presents the design process of a cross-sports footwear concept, built on the basis of the principles of ecodesign

  15. Design Education

    DEFF Research Database (Denmark)

    Brandt, Eva

    2007-01-01

    In resent years the two main design schools in Denmark (Danmarks Designskole and Designskolen Kolding ) undergo many changes. The overall goal for both is to obtain status as a university, and they will be evaluated in this regard in 2010. Transforming a vocational school with long handicraft...... traditions into a research based institution for higher education is demanding. Danmarks Designskole is in the middle of this process, many activities are initiated, both employees and students are involved, and from outside representatives from various design professions. The design process has many...... stakeholders with various interests and opinions. The aim it is not to design a computer system, a service or product but re-designing curriculum, work procedures, self images etc. which support educating designers of the future. This paper reports on two investigations that have been carried through as part...

  16. Cooperative design

    DEFF Research Database (Denmark)

    Schmidt, Kjeld

    1998-01-01

    In the contemporary world, engineers and designers face huge challenges as they shift towards novel organizational concepts such as ‘concurrent engineering’ in order to manage increasing product diversity so as to satisfy customer demands while trying to accelerate the design process to deal...... they are facing. On one hand, designers need highly flexible ‘coordination mecha-nisms’ that can support horizontal coordination of large-scale distributed design projects, and on the other hand design organizations require versatile and ubiquitous infrastructures to be able to manage their ‘common informa...... with the competitive realities of a global market and decreasing product life cycles. In this environment, the coordination and integration of the myriads of interdependent and yet distributed and concurrent design activities becomes enormously complex. It thus seems as if CSCW technologies may be indispensable...

  17. Workspace Design

    DEFF Research Database (Denmark)

    Seim, Rikke

    Arbejdsmiljø adresseres sjældent i den klassike tekniske tilgang til arbejdspladsdesign. Workspace Design konceptet er et alternativ tilgang til design eller re-design af arbejdspladser, baseret på en socio-teknisk systemforståelse, hvor hovedprincipperne er 1) transformation af...... arbejdsmiljørådgiveren til facilitator af arbejdspladsdesignprocessen og 2) transformation af medarbejderne til co-designere af deres egen arbejdsplads. Dette ph.d.-projekt er en del af Workspace Design forskningsprogrammet som har udviklet og testet Workspace Design konceptet og de tilhørende metoder ved intervention i...... arbejdspladsdesignprocesser i tre virksomheder tilhørende henholdsvis industri-, service- og sundhedssektoren. Ph.d.-projektet har belyst hvordan en medarbejderinvolverende designproces kan iscenesættes og faciliteres af arbejdsmiljøprofessionelle ved hjælp af kreative, visuelle metoder inspireret af Participatory Design...

  18. Design culture and design education

    DEFF Research Database (Denmark)

    Riisberg, Vibeke; Bang, Anne Louise

    2014-01-01

    to change the education of future designers. This is an emerging field at a number of design schools across the world, among these Design School Kolding in Denmark. In this paper we understand and discuss design education as part of a cultural phenomenon. The aim of our research is to develop new dialogue...... tools for teaching fashion and textile students in order to stimulate new ways of thinking and engaging with users. By employing participatory design methods in the field of fashion and textiles, we seek to develop an alternative transformational strategy that may further the design of products....... In this paper we discuss ways in which design education might contribute in changing the current professional culture in order to meet the need for more sustainable futures....

  19. Integrated Design

    DEFF Research Database (Denmark)

    Jørgensen, Michael; Nielsen, M. W.; Strømann-Andersen, Jakob Bjørn

    2011-01-01

    and describe the decision process. Specific attention is given to how the engineering input was presented and how it was able to facilitate the design development. Site and context, building shape, organization of functions and HVAC-systems were all included to obtain a complete picture of the building......, low-energy consumption, and high-quality indoor environment. We use this case study to investigate how technical knowledge about building performance can be integrated into the conceptual design stage. We have selected certain points during the design process that represented design challenges...

  20. Design Diversity

    DEFF Research Database (Denmark)

    Dankl, Kathrina

    2014-01-01

    . The exhibition is oriented along disciplines such as inclusive design, which calls for products to be designed in such a way that they are equally attractive to people of all ages. Despite the existence of innovative design concepts, the number of well-designed products available on the market is low. While many...... courageous projects for "best agers" and "golden agers" never get beyond the prototype stage, products that paint a more "beige" picture of everyday life can be found in large numbers. This fact raises some key questions: Does the existing product culture reflect today's views on old age? Do contemporary...

  1. Team designing

    DEFF Research Database (Denmark)

    Denise J. Stokholm, Marianne

    2012-01-01

    Future wellbeing is depending on human competences in order to strengthen a sustainable development. This requires system thinking and ability to deal with complexity, dynamic and a vast of information. `We need to move away from present principles of breaking down problems into components and gi...... thinking and communication in design. Trying to answer the question: How can visual system models facilitate learning in design thinking and team designing?......Future wellbeing is depending on human competences in order to strengthen a sustainable development. This requires system thinking and ability to deal with complexity, dynamic and a vast of information. `We need to move away from present principles of breaking down problems into components and give...... in relation to a design-engineering education at Aalborg University. It will exemplify how the model has been used in workshops on team designing, challenged design learning and affected design competence. In specific it will investigate the influence of visual models of the perception of design, design...

  2. Design Compass

    DEFF Research Database (Denmark)

    Stokholm, Marianne Denise J.

    2006-01-01

    Design is moreover recognised as an important strategic tool in achieving competitive business´, products and services in a global market. As design becomes a more complex matter, due to a general increase in knowledge, requirements and internationalisation, more professions are involved....... As such it acts a managing tool for both leaders and participants in the design process. This paper builds on long term practical experiment with development and use of a simple tool to support management of complex design matters in diverse groups. Concerning education it has supported the development of new...

  3. Designated Places

    Data.gov (United States)

    California Natural Resource Agency — Census 2000 Place Names provides a seamless statewide GIS layer of places, including census designated places (CDP), consolidated cities, and incorporated places,...

  4. Design theory

    CERN Document Server

    2009-01-01

    This book deals with the basic subjects of design theory. It begins with balanced incomplete block designs, various constructions of which are described in ample detail. In particular, finite projective and affine planes, difference sets and Hadamard matrices, as tools to construct balanced incomplete block designs, are included. Orthogonal latin squares are also treated in detail. Zhu's simpler proof of the falsity of Euler's conjecture is included. The construction of some classes of balanced incomplete block designs, such as Steiner triple systems and Kirkman triple systems, are also given.

  5. Cryostat Design

    Energy Technology Data Exchange (ETDEWEB)

    Parma, V [European Organization for Nuclear Research, Geneva (Switzerland)

    2014-07-01

    This paper aims to give non-expert engineers and scientists working in the domain of accelerators a general introduction to the main disciplines and technologies involved in the design and construction of accelerator cryostats. Far from being an exhaustive coverage of these topics, an attempt is made to provide simple design and calculation rules for a preliminary design of cryostats. Recurrent reference is made to the Large Hadron Collider magnet cryostats, as most of the material presented is taken from their design and construction at CERN.

  6. Interior Design.

    Science.gov (United States)

    Texas Tech Univ., Lubbock. Home Economics Curriculum Center.

    This document contains teacher's materials for an eight-unit secondary education vocational home economics course on interior design. The units cover period styles of interiors, furniture and accessories, surface treatments and lighting, appliances and equipment, design and space planning in home and business settings, occupant needs, acquisition…

  7. Opportunity Design

    DEFF Research Database (Denmark)

    Løwe Nielsen, Suna; Lassen, Astrid Heidemann; Nielsen, Louise Møller

    2013-01-01

    design”. The framework explains how opportunities intentionally and pro-actively can be designed from methods and processes of moving-in and moving-out. An illustrative case of opportunity design within the area of sustainable energy and electric cars is presented to link the theoretical discussion...

  8. Publication Design.

    Science.gov (United States)

    Nelson, Roy Paul

    This book is designed to solve the problem of coordinating art and typography with content in publications. Through text and illustrations, this book suggests ways to make pages and spreads in magazines, newspapers, and books attractive and readable. As a book of techniques, it is directed at potential and practicing art directors, designers, and…

  9. Designing friends

    NARCIS (Netherlands)

    Heylen, Dirk K.J.; Nijholt, Antinus; Stronks, B.; van der Vet, P.E.; Rosenberg, D.

    2003-01-01

    Embodied Conversational Agents are virtual humans that can interact with humans using verbal and non-verbal forms of communication. In most cases, they have been designed for short interactions. This paper asks the question how one would start to design synthetic characters that can become your

  10. Design tools

    Science.gov (United States)

    Anton TenWolde; Mark T. Bomberg

    2009-01-01

    Overall, despite the lack of exact input data, the use of design tools, including models, is much superior to the simple following of rules of thumbs, and a moisture analysis should be standard procedure for any building envelope design. Exceptions can only be made for buildings in the same climate, similar occupancy, and similar envelope construction. This chapter...

  11. Integrated Design

    DEFF Research Database (Denmark)

    Lenau, Torben Anker

    1999-01-01

    A homepage on the internet with course material, lecture plan, student exercises, etc. Continuesly updated during the course Integrated Design (80402, 80403)......A homepage on the internet with course material, lecture plan, student exercises, etc. Continuesly updated during the course Integrated Design (80402, 80403)...

  12. Persuasive Design

    DEFF Research Database (Denmark)

    Gram-Hansen, Sandra Burri

    2013-01-01

    of the specific context. This paper argues that the claim of persuasive design may not be the ability to change the user’s attitude or behaviour towards a given subject, but rather on the ability to create designs, which adapt the context in a way, which facilitates the ability to act within the opportune moment....

  13. Japansk design

    DEFF Research Database (Denmark)

    Kural, René

    2005-01-01

    Artiklen udspringer af interviews med ti af Japans bedste møbeldesignere, grafikere, arkitekter og designfirmaer. Efter samtalerne var der tre træk ved japansk design, som trådte frem: god økonomi, fantasi og vovemod. Det bedste japanske design fusionerer vovemod med den unikke japanske kultur med...

  14. Intelligent Design

    DEFF Research Database (Denmark)

    Hjorth, Poul G.

    2005-01-01

    Forestillingen om at naturen er designet af en guddommelig 'intelligens' er et smukt filosofisk princip. Teorier om Intelligent Design som en naturvidenskabeligt baseret teori er derimod helt forfærdelig.......Forestillingen om at naturen er designet af en guddommelig 'intelligens' er et smukt filosofisk princip. Teorier om Intelligent Design som en naturvidenskabeligt baseret teori er derimod helt forfærdelig....

  15. Performance Design

    DEFF Research Database (Denmark)

    Svabo, Connie

    Contribution to conference: Art and Presence The emerging field of Performance Design is unfolded as a bastard form of research/art/design/practice, with shapeshifting, monstruous, hybrid and transformational qualities. The potential for presencing, which emerges out of momentarily transgressing...

  16. Design law

    DEFF Research Database (Denmark)

    Schovsbo, Jens Hemmingsen; Riis, Thomas

    2017-01-01

    This book chapter describes, analyses and discusses the development of and the challenges to the legal protection og designs in Scandinavia and the EU......This book chapter describes, analyses and discusses the development of and the challenges to the legal protection og designs in Scandinavia and the EU...

  17. Furniture design

    CERN Document Server

    Smardzewski, Jerzy

    2015-01-01

    Maximizing reader insights into the principles of designing furniture as wooden structures, this book discusses issues related to the history of furniture structures, their classification and characteristics, ergonomic approaches to anthropometric requirements and safety of use. It presents key methods and highlights common errors in designing the characteristics of the materials, components, joints and structures, as well as looking at the challenges regarding developing associated design documentation. Including analysis of how designers may go about calculating the stiffness and endurance of parts, joints and whole structures, the book analyzes questions regarding the loss of furniture stability and the resulting threats to health of the user, putting forward a concept of furniture design as an engineering processes. Creating an attractive, functional, ergonomic and safe piece of furniture is not only the fruit of the work of individual architects and artists, but requires an effort of many people working ...

  18. Mobilities Design

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lanng, Ditte Bendix; Wind, Simon

    2016-01-01

    In this paper, we identify the nexus between design (architecture, urban design, service design, etc.) and mobilities as a new and emerging research field. In this paper, we apply a “situational mobilities” perspective and take point of departure in the pragmatist question: “What design decisions...... and interventions affords this particular mobile situation?” The paper presents the contours of an emerging research agenda within mobilities research. The advent of “mobilities design” as an emerging research field points towards a critical interest in the material as well as practical consequences of contemporary......-making. The paper proposes that increased understanding of the material affordances facilitated through design provides important insight to planning and policymaking that at times might be in risk of becoming too detached from the everyday life of the mobile subject within contemporary mobilities landscapes....

  19. Design of high quality doped CeO2 solid electrolytes with nanohetero structure

    International Nuclear Information System (INIS)

    Mori, T.; Ou, D.R.; Ye, F.; Drennan, J.

    2006-01-01

    Doped cerium (CeO 2 ) compounds are fluorite related oxides which show oxide ionic conductivity higher than yttria-stabilized zirconia in oxidizing atmosphere. As a consequence of this, a considerable interest has been shown in application of these materials for low (400-650 o C) temperature operation of solid oxide fuel cells (SOFCs). In this paper, our experimental data about the influence of microstructure at the atomic level on electrochemical properties were reviewed in order to develop high quality doped CeO 2 electrolytes in fuel cell applications. Using this data in the present paper, our original idea for a design of nanodomain structure in doped CeO 2 electrolytes was suggested. The nanosized powders and dense sintered bodies of M doped CeO 2 (M:Sm,Gd,La,Y,Yb, and Dy) compounds were fabricated. Also nanostructural features in these specimens were introduced for conclusion of relationship between electrolytic properties and domain structure in doped CeO 2 . It is essential that the electrolytic properties in doped CeO 2 solid electrolytes reflect in changes of microstructure even down to the atomic scale. Accordingly, a combined approach of nanostructure fabrication, electrical measurement and structure characterization was required to develop superior quality doped CeO 2 electrolytes in the fuel cells. (author)

  20. Fuel cell-gas turbine hybrid system design part II: Dynamics and control

    Science.gov (United States)

    McLarty, Dustin; Brouwer, Jack; Samuelsen, Scott

    2014-05-01

    Fuel cell gas turbine hybrid systems have achieved ultra-high efficiency and ultra-low emissions at small scales, but have yet to demonstrate effective dynamic responsiveness or base-load cost savings. Fuel cell systems and hybrid prototypes have not utilized controls to address thermal cycling during load following operation, and have thus been relegated to the less valuable base-load and peak shaving power market. Additionally, pressurized hybrid topping cycles have exhibited increased stall/surge characteristics particularly during off-design operation. This paper evaluates additional control actuators with simple control methods capable of mitigating spatial temperature variation and stall/surge risk during load following operation of hybrid fuel cell systems. The novel use of detailed, spatially resolved, physical fuel cell and turbine models in an integrated system simulation enables the development and evaluation of these additional control methods. It is shown that the hybrid system can achieve greater dynamic response over a larger operating envelope than either individual sub-system; the fuel cell or gas turbine. Results indicate that a combined feed-forward, P-I and cascade control strategy is capable of handling moderate perturbations and achieving a 2:1 (MCFC) or 4:1 (SOFC) turndown ratio while retaining >65% fuel-to-electricity efficiency, while maintaining an acceptable stack temperature profile and stall/surge margin.