A Three-Dimensional Time-Dependent Model of the Degradation Caused by Chromium Poisoning in a Solid Oxide Fuel Cell Stack

Abstract

Chromium poisoning strongly influences the performance of solid oxide fuel cell (SOFC) stacks. A novel numerical model is introduced by incorporating the chemical and electrochemical aspects of chromium poisoning. It offers a detailed analysis of the spatial distribution of critical chromium-based species, including SrCrO4 and Cr2O3. This model is integrated with a pre-existing three-dimensional, time-dependent computational fluid dynamics (CFD) toolbox, openFuelCell2. The numerical simulations indicate a quantitative agreement with experimental data over an extended 100 kh operation. Numerical simulations are conducted within a representative channel geometry originating from an F10 SOFC stack at Forschungszentrum Jülich GmbH, and consider a wide range of stack designs, temperatures, and air absolute humidities. The simulation results demonstrate the potential of a protective coating produced through atmospheric plasma spraying (APS) technology in nearly eliminating chromium poisoning. It is also found that the APS protective coating could enable the operation of an SOFC stack with low requirements of air dehumidification at a temperature of 650 ∘C.