Steam reforming reactions over a metal-monolithic anodic alumina-supported Ni catalyst with trace amounts of noble metal

Abstract

A trace amount of noble metal (Ru or Pt <0.1 wt%) was doped onto an anodic alumina-supported Ni catalyst, to investigate its performance in the steam reforming of methane (SRM), especially during DSS (daily startup and shutdown) operation. Although the steam purge treatment at high temperatures seriously deactivated the Ni catalyst because of the oxidation of metallic nickel with steam into Ni 2+, trace Ru assisted the regeneration of active metallic nickel by hydrogen-spillover. And, the Ni sintering was largely alleviated by the addition of Ru, and it was probably due to the formation of Ru–Ni alloy. In comparison with the Ru-doped Ni catalyst, the Pt-doped Ni catalyst showed a more favorable tolerance to steam oxidation, even at 900 °C. In a stationary SRM test of 3000 h and a DSS SRM test of 500 times where the town gas 13A was used as hydrogen source, no obvious deterioration was detected over the Pt-doped Ni catalyst. Especially, when electrically heating the plate-type Pt-doped Ni catalyst to 700 °C, the SRM reaction system could reach a stable state within ca. 10 min, which offered a strong possibility to shorten the startup time from the 1–2 h of conventional reformer to just few minutes. In addition, the noble metal-doped Ni catalyst also showed favorable activity and durability when being applied to other steam reforming systems, such as kerosene and ethanol.