Deactivation behaviors of Pt or Ru promoted Co/P-Al₂O ₃ catalysts during slurry-phase Fischer-Tropsch synthesis

The catalytic stability of cobalt-based catalyst using phosphorous-modified alumina support (P-Al₂O₃), promoted with Pt or Ru, during Fischer-Tropsch synthesis (FTS) has been investigated for 1000 h on stream using a slurry-phase continuous-stirred tank reactor. Although catalytic properties such as surface area and particle size of metallic cobalt are similar for both the catalysts, the different deactivation behaviors were observed with respect to the kind of noble metal addition. The slower catalyst deactivation was observed on Pt promoted Co/P-Al₂O₃ catalyst than Ru promoted one, which seems to be owing to small deposition of polymeric carbons on the surface, confirmed by hydrogenation of surface carbons, and suppressed formation of aggregated catalyst lump at the beginning of FTS reaction.