Design and Optimization of Chromium Getter for SOFC Systems through Computational Modeling

Abstract

Chromium poisoning is one of the major causes of cathode degradation in high temperature electrochemical systems such as solid oxide fuel cells, electrolyzers and oxygen transport membranes. Chromium species, evaporating from the chromia forming metallic balance of plant and cell interconnect components, deposit at the exposed electrode surface and triple phase boundaries resulting in irrecoverable performance degradation. Chromium capture approach comprising of the use of non-noble and non- strategic getter materials and conventional ceramic support, currently being developed and tested in our laboratory, will be presented and discussed. Simulation of the chromium getter under nominal SOFC system operating conditions include a single channel with porous region at the wall to simulate the getter coating on cordierite honeycomb support (400 cells per square inch) with a coating thickness of 10µm and 50% porosity. The model is validated against experimental data and utilized to study the effects of the key parameters such as chromium partial pressure, air flow rate, geometric surface area, porosity, and thickness of coating materials.