| 1. |
- Abbas, Ghazanfar, et al.
(författare)
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Preparation and characterization of nanocomposite calcium doped ceria electrolyte with alkali carbonates (NK-CDC) for SOFC
- 2010
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Ingår i: ASME 2010 8th International Conference on Fuel Cell Science, Engineering and Technology, FUELCELL 2010. - : ASME Press. - 9780791844052 ; , s. 427-432
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Konferensbidrag (refereegranskat)abstract
- The entire world's challenge is to find out the renewable energy sources due to rapid depletion of fossil fuels because of their high consumption. Solid Oxide Fuel Cells (SOFCs) are believed to be the best alternative source which converts chemical energy into electricity without combustion. Nanostructured study is required to develop highly ionic conductive electrolyte for SOFCs. In this work, the calcium doped ceria (Ce0.8Ca0.2O 1.9) coated with 20% molar ratio of two alkali carbonates (CDC-M: MCO3, where M= Na and K) electrolyte was prepared by co-precipitation method in this study. Ni based electrode was used to fabricate the cell by dry pressing technique. The crystal structure and surface morphology was characterized by X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM). The particle size was calculated in the range of 10-20nm by Scherrer's formula and compared with SEM and TEM results. The ionic conductivity was measured by using AC Electrochemical Impedance Spectroscopy (EIS) method. The activation energy was also evaluated. The performance of the cell was measured 0.567W/cm2 at temperature 550°C with hydrogen as a fuel.
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| 2. |
- Andersson, Daniel, et al.
(författare)
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Dynamic Modeling Of A Solid Oxide Fuel Cell System In Modelica
- 2010
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Ingår i: Proceedings of the Asme 8th International Conference on Fuel Cell Science, Engineering, and Technology 2010, Vol 2. - 9780791844052 ; 2, s. 65-72
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Konferensbidrag (refereegranskat)abstract
- In this study a dynamic model of a solid oxide fuel cell (SOFC) system has been developed. The work has been conducted in a cooperation between the Department of Energy Sciences, Lund University, and Mode Ion AB using the Modelica language and the Dymola modeling and simulation tool. Modelica is an equation based, object oriented modeling language, which promotes flexibility and reuse of code. The objective of the study is to investigate the suitability of the Modelica language for dynamic fuel cell system modeling. A cell electrolyte model including ohmic, activation and concentration irreversibilities is implemented and verified against simulations and experimental data presented in the open literature. A ID solid oxide fuel cell model is created by integrating the electrolyte model and a ID fuel flow model, which includes dynamic internal steam reforming of methane and water-gas shift reactions. Several cells are then placed with parallel flow paths and connected thermally and electrically in series. By introducing a manifold pressure drop, a stack model is created. The stack model is applied in a complete system including an autothermal reformer, a catalytic afterburner, a steam generator and heat exchangers. Four reactions are modeled in the autothermal reformer; two types of methane steam reforming, the water-gas shift reaction and total combustion of methane. The simulation results have been compared with those in the literature and it can be concluded that the models are accurate and that Dymola and Modelica are tools well suited for simulations of the transient fuel cell system behaviour.
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| 3. |
- Paradis, Hedvig, et al.
(författare)
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CFD Modeling Considering Different Kinetic Models for Internal Reforming Reactions in an Anode-Supported SOFC
- 2010
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Ingår i: ASME 2010 8th International Fuel Cell Science, Engineering and Technology Conference. - 9780791844052 ; 2:FuelCell2010-33045, s. 55-64
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Konferensbidrag (refereegranskat)abstract
- Fuel cells are electrochemical devices that transform chemical energy into electricity. Solid oxide fuel cells (SOFCs) are particularly interesting because they can handle the reforming of hydrocarbon fuels directly within the cell. This is possible due to their high operating temperature. The purpose of this study is to develop an anode-supported SOFC model, to enhance the understanding of the internal reforming and effects on the transport processes. In this study, a CFD approach, based on the finite element method, is implemented for the analysis to unravel the interaction between internal reforming, momentum, heat and mass transport. The three different reaction rates applied in this study were developed and correlated through experimental studies found in the literature. An equilibrium equation is implemented for the reaction rate for the water-gas shift reaction. The pre-exponential values, in relation to the partial pressures and reaction order of the pressure are found to partly affect the reaction rate.
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