Startup Strategy for Operating a Solid Oxide Fuel Cell Based on Transient Analyses

Abstract

In this paper, conservations of charge, mass, and energy are implemented to establish the basic relationship between voltage and current as well as the mathematical model for investigating the transient behavior of a planar SOFC. Typical response time and temperature ramp rate of the SOFC under steady operating conditions are calculated first and ascend with increasing current density. Furthermore, transient behavior is investigated by setting a series of step functions of current density to simulate various startup operating modes. To avoid the temperature ramp rate being too high during the startup period, stepwise increment of the current density seems to be more suitable. For example, the three-step increment series of 300 mA/cm2, 500 mA/cm2 and 640 mA/cm2 would result in a temperature ramp rate complied with a given specification, e.g., less than 5°C per minute, while the total response time is in a moderate range as well.