A dynamic model of an atmospheric solid oxide fuel cell system for stationary power generation

This paper focuses on the transient behavior of a solid oxide fuel cell system used for stationary power production. Dynamic modelling is applied to identify the characteristic time scales of the system components when introducing a disturbance in operational parameters of the system. The information on the response of the system may be used to specify the control loops needed to manage the changes with respect to safe component operation. The commercial process modelling tool gPROMS is used to perform the system simulations. The component library of the tool is completed with dynamic models of a fuel cell stack and a prereformer. The other components are modelled for steady state operation. For the fuel cell a detailed dynamic model is obtained by writing the constitutive laws for heat transfer in the solid part of the cell and conservation of heat and mass in the air and fuel channels. Comprehensive representation of resistive cell losses, reaction kinetics for the reforming and heat conduction through the solid part of the cell is also included in the model. The prereformer is described as a dynamic pseudo-homogeneous onedimensional tubular reactor accounting for methane steam reforming and water-gas shift reaction. The differences in the transient behavior of the system components and their interaction are investigated under load changes and feed disturbances.