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This paper presents experimental and numerical investigations of methane/steam reforming process over a Ni/YSZ catalyst for SOFCs. Designing and optimizing an indirect internal reformer and a cell with direct reforming for an SOFC application require precise kinetic data. The generalized least squares (GLS) method was applied to evaluate the reaction rate. Mathematical modeling of the process coupled with the GLS algorithm and numerical analyses pointed out that the experimental inaccuracy could be reduced. The proposed algorithm allows for the calculation of the most probable values of kinetic parameters and uncertainties of the obtained results.

The present paper describes numerical modelling of the radiative heat transfer process in the module chamber of an Internal Indirect Reforming-type SOFC. The ability to do internal reforming is one of the characteristics of high temperature fuel cells, SOFC. As in any high-temperature system, radiative heat transfer is important. In this article, heat transfer between the fuel reformer surface and all other surfaces facing to the reformer surfaces is modelled. Governing equations for radiative heat transfer are described using Hottel's zone method. The resulting radiation-conduction conjugate heat transfer problems are numerically solved with a combination of Gauss-Seidel and Newton-Raphson methods. The obtained results indicate that, for the development of effective indirect internal reforming, the position of the reformer in the module chamber and emissivity of the surfaces of the reformer, cell and other elements in the SOFC module all play a key role.

This paper presents study on methane/steam reforming process and method to develop effective experimental-calculation procedure to deliver the reliable kinetic reaction rate expression with the decreased number of necessary experimental measurements for the calculations of the empirical parameters. The experimental studies were conducted on the NiO/YSZ (60/40vol%) catalyst, one of the most typical materials, for Solid Oxide Fuel Cell anodes. By the analysis with the Orthogonal Least Squares method and an analysis of a-posterioricovariance matrix, the experimentation process has been optimized. The proposed systematic approach was applied to evaluate the minimal number of measurements required to achieve the assumed accuracy of final solution and to reveal the influence of distribution of experimental condition for the quality of final reaction kinetic equation. It was proved that the number of experimental measurements can be reduced without significant deterioration in the quality of solution, if the dismissed measurements are properly chosen.

In this research a cell stack with standard power output 100 W was tested over the period of 3700 hours. After the long-term operation subsequent post-test analysis of anode microstructure has been conducted using combination of focused ion beam and scanning electron microscopy. Obtained data was reconstructed into three-dimensional images, based on which the microstructure parameters were obtained. The microstructure parameters were quantified at three different location in the selected cells; inlet, middle and outlet. The obtained results indicate strong microstructure morphology change after long operation time and revealed a non-homogeneous degradation behavior.