Modelling Internal Reforming Solid Oxide Fuel Cells with Surface Chemistry to Find Regions Susceptible to Carbon Deposition

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Abstract

The lifespan of internal reforming solid oxide fuel cells (SOFCs) is not yet sufficient. Among other design challenges, this is due to detrimental carbon deposition formations. This must be mitigated, without compromising the power output and efficiency of the fuel cell for it to become a commercial viable product. The carbon that is deposited originates from a methane/hydrogen mixture, fed to the fuel cell. All failure modes caused either directly or indirectly by carbon formations are explored. A 3D-model representing part of an SOFC is modelled, in order to identify areas specially susceptible to carbon depositing on the anode. The methane is reformed by a surface chemistry mechanism developed with density functional theory. By doing this, it is possible to model both reaction kinetics and reaction equilibrium of the reforming process.
The final model can accurately model local mixture composition, as well as surface site coverage. The reaction rate and activation energy of methane reforming on a nickel catalyst is also calculated by using the output of the simulations. The site coverage observed can lead to further carbon deposition, but this is not yet modelled.