The dynamic response of solid oxide fuel cell fueled by syngas during the operating condition variations

Abstract

This work investigates the dynamic characteristics of solid oxide fuel cell (SOFC) under variation operating conditions and complements the dynamic response characteristics on SOFC operating end. The dynamic characteristics is significant to dynamic operation and performance control. The classical appropriate transfer functions are proposed to capture the practical changing process of operating conditions for the first time. The dynamic multi-physical field model is developed as a mapping function to obtain the dynamic characteristics. The SOFC will be stabilized again within 100 s after the flow rate variations, which means that SOFC can be in another stable operation. The current density obviously goes through an overshoot phase and then gradually reaches stability caused by cathode flow rate variation. While, the change of anode flow does not cause overshoot. It is also found that the “fuel starvation” phenomenon also does not exist during flow rate variations, which means the “fuel starvation” hardly needs to be considered under non-extreme changes in operating conditions. The step function is used to simulate the change process of syngas composition. The increase in current density can be divided into two stages, which last about 100 s totally. The variation amplitude of current density due to the fuel composition variation is relatively small, which means the change in fuel composition doesn't cause a very dramatic response. The cell length has relative significance influence on the dynamic characteristic. This dynamic model could also be used to simulate the dynamic response of SOFC with different geometric structures, especially those with large changes in length and direction. This work is expected to uncover the dynamic response characteristics of SOFC under the variations of operating parameters, and to provide data support and theoretical guidance for SOFC under variable operating conditions and performance control.