Development of a Structured Graded Catalyst System for the Catalytic Partial Oxidation of Hydrocarbons

Reforming hydrocarbons into a H₂- and CO-rich gas stream for solid oxide fuel cell transportation applications requires a catalyst system with thermal and mechanical stability and resistance to deactivation in the presence of common contaminants. Liquid fuels considered appropriate for these applications often contain sulfur and aromatic compounds that poison and deactivate catalysts, specifically through carbon formation. Typically, precious metal catalysts like Rh have been used to achieve the desired performance for the CPOX of these hydrocarbons. However, these catalysts are very expensive. This work examines the use of a graded catalyst bed to reduce the amount of precious metal needed to produce the level of performance necessary for commercial viability. Further, this work examines the development of a commercially representative catalyst system by applying the graded catalyst approach to a structured monolith. The CPOX of a diesel surrogate and a biodiesel fuel have been demonstrated previously using a single-composition monolith. This work demonstrates the potential benefit of a multi-composition monolith comprised of Ni-, Ru-, and Rh-substituted oxide catalysts deposited onto alumina foams.