Modelling mass transport in solid oxide fuel cell anodes: a case for a multidimensional dusty gas-based model

Abstract

In this work the mass transport phenomena taking place in the fuel channel and the porous electrode of the anode of planar solid oxide fuel cells (SOFCs) are discussed. A comprehensive review of SOFC mass transport models in the literature is given and a new multidimensional, multicomponent, isothermal, dynamic model of the mass transport phenomena taking place in the fuel channel and the porous electrode of the anode of planar SOFCs is presented. The model can be used to predict species composition profiles and is based on the dusty-gas model (DGM) [Mason, E.A., Malinauskas, A.P., 1983. Gas Transport in Porous Media: The Dusty-Gas Model: Elsevier; Jackson, R., 1977. Transport in Porous Catalysts: Elsevier], which is considered to be the most accurate of the existing mass transfer models in porous media [Suwanwarangkul, R., Croiset, E., Fowler, M.W., Douglas, P.L., Entchev, E., Douglas, M.A., 2003. Performance comparison of Fick's, dusty-gas and Stefan–Maxwell models to predict the concentration overpotential of a SOFC anode. Journal of Power Sources 122, 9-18]. Our two-dimensional DGM is validated using experimental data [Yakabe, H., Hishinuma, M., Uratani, M., Matsuzaki, Y., Yasuda, I., 2000. Evaluation and modeling of performance of anode-supported solid oxide fuel cell. Journal of Power Sources 86, 423-431] and it is tested against a two-dimensional Stefan–Maxwell model (SMM) and against one-dimensional models (Fick's model, SMM and DGM) reported in the literature. It is shown that a detailed model is essential for the accurate prediction of concentration overpotentials especially at high fuel utilisation conditions, which are typical operating conditions for fuel cells [Hernández-Pacheco, E., Singh, D., Hutton, P.N., Patel, N., Mann, M.D., 2004. A macro-level model for determining the performance characteristics of solid oxide fuel cells. Journal of Power Sources 138, 174-186].