PNNL

Abstract

OLID oxide fuel cells (SOFCs) hold the promise of playing a major role in future power grids either as distributed generators (DGs) or as stand-alone power units because of their higher efficiency, lower emission, modular structure, and higher generation capability over other DGs or batteries. SOFCs operate at temperatures ranging from 600°C to 1000°C. To avoid thermal shock during heat-up as well as operation, inlet flow (fuel and air) temperatures and speeds must be carefully controlled to maintain the temperature gradient within the SOFC stack. Furthermore, increased fuel flow tends to decrease the fuel utilization and increase uniformity of the reaction rates across the active area, while decreased fuel flow tends to increase the fuel utilization but it can cause local fuel depletion and cold spots that exacerbate temperature non-uniformities [1]. Therefore, when maintaining reasonable fuel utilization at any loading level, the air flow rate and the fuel flow rate must be adjusted so that the fuel distribution and temperature gradient across the cell is more uniform.