Dynamics and Control of a Tubular Solid-Oxide Fuel Cell

Abstract

This paper presents a study of the dynamic behavior and control of a tubular solid oxide fuel cell system. A dynamic compartmental model that is based on first principles is developed. The model accounts for diffusion processes, inherent impedance, transport (heat and mass transfer) processes, electrochemical processes, anode and cathode activation polarizations, and internal reforming/shifting reactions, among others. Dynamic outlet voltage, current, and fuel-cell−tube temperature responses of the cell to step changes in external load resistance and conditions of the feed streams are presented. Simulation results show that the fuel cell is a multitime-scale system; some of the cell output responses exhibit consecutive apparent dominant time constants, ranging from ∼0.2 ms to ∼40 s. They also reveal that the temperature and pressure of the inlet air stream and the temperature of the inlet fuel stream strongly affect the dynamics of the fuel cell system. The temperature of the inlet air stream has the stro...