Effect of relative bed lengths on a Platinum/Nickel stratified dual bed catalyst for the catalytic partial oxidation of methane at millisecond contact times

Stratified, dual bed catalysts composed of platinum followed by nickel have shown reactant conversions and product selectivities similar to rhodium, which has shown the highest activity for the millisecond catalytic partial oxidation reaction. The goal of the stratified catalyst is to carry out the catalytic partial oxidation in a two-step process: combustion catalyzed by platinum followed by steam and carbon dioxide reforming catalyzed by nickel. Previous studies have shown that sequential platinum and nickel beds with the same space velocity have high activity and long-term stability. In this work, the relative bed length of the platinum and nickel catalysts is investigated. Since combustion occurs much faster than reforming, the platinum bed can be much shorter than the nickel bed. Experiments show that the relative bed length of platinum can be much smaller than that of nickel in the dual bed catalyst. Reducing the amount of platinum increases the methane conversion and hydrogen selectivity while reducing the carbon monoxide selectivity. Degradation studies under harsh operating conditions show that the catalyst is stable. The number of potential experiments required to optimize this system leads one to believe a simulation-based approach will be more efficient.