Catalytic degradation of aqueous Fischer-Tropsch effluents to fuel gas over oxide-supported Ru catalysts and hydrothermal stability of catalysts

BACKGROUND: The catalytic degradation of aqueous FischerTropsch (FT) effluents to fuel gas over Ru/AC has been investigated. In order to understand the catalytic performance and stability of oxide-supported Ru catalysts, several oxide supports (titania, zirconia, ?-alumina and silica) were selected for study, with a focus on the hydrothermal stability of catalysts. RESULTS: The catalytic efficiency for transforming the oxygenates in aqueous FT effluents to C1C6 alkanes decreased in the order: Ru/ZrO2 similar to Ru/TiO2 > Ru/SiO2 > Ru/Al2O3. The conversion of alcohols was greatly suppressed over Ru/?-Al2O3. The former two catalysts (Ru/ZrO2 and Ru/TiO2) exhibited enhanced efficiency and long-term stability (400 h) relative to Ru/SiO2 and Ru/Al2O3. N2-physisorption, XRD and SEM showed that titania and zirconia exhibited high structural stability in an aqueous environment. However, the structures of ?-alumina and silica were unstable due to significant drop in surface area and adverse changes in surface morphology. Especially for the case of the Ru/?-Al2O3 catalyst, the ?-alumina was transformed into boehmite structure after reaction, and metal leaching and carbon deposition were extensive. CONCLUSION: Ru/ZrO2 or Ru/TiO2 may be a promising alternative for degrading aqueous FT effluents due to their long-term stability. Copyright (C) 2012 Society of Chemical Industry