Comparative evaluation of Ru-coated fecralloy and SiC monolithic catalysts in catalytic partial oxidation of natural gas for hydrogen production

The catalytic activity of structured catalysts comprising Fecralloy and SiC monoliths coated with Ru/Mg-Al oxide by deposition–precipitation was evaluated in the partial oxidation of natural gas and compared with that of a conventional pellet catalyst. The geometric surface area (GSA) of the Fecralloy and SiC monolithic catalysts were 377.0 × 10-4 and 118.5 × 10-4 m2, respectively; significantly larger than that of the 0.5% Ru/Al2O3 pellet catalyst (89.6 × 10-4 m2). Owing to the high GSA of the structured catalysts, a small amount of Ru (0.070–0.12 wt%) resulted in highly dispersed uniform loading. Thus, the structured catalysts exhibited higher performance for catalytic partial oxidation at varying C/O2 ratio, inlet temperature, and gas hourly space velocity (GHSV) than the pellet catalyst. However, in a stability test at high GHSV (50,000 h−1), the CH4 conversion of the Fecralloy monolithic catalyst decreased rapidly from 90% to less than 70% in 150 min. In addition, the Mg-Al oxide layer of the Fecralloy monolithic catalyst was damaged owing to material deterioration, resulting in a loss of Ru particles. In contrast, CH4 conversion catalyzed by the SiC monolithic catalysts remained above 85% even after 1000 min, and the material or support layer was not damaged even under severe conditions.