2010 Volume 53 Issue 4 Pages 222-231
A series of Ru/Mn/Al2O3 catalysts with different concentrations of manganese were investigated on catalyst characterization and activity for Fischer-Tropsch synthesis in a continuous stirred tank reactor. The Ru/Al2O3 and Ru/MnO showed low catalytic activity and deactivation rate was clearly observed at 493 K and 2 MPa. On the other hand, the addition of small amount of manganese in Ru/Mn/Al2O3 (Mn/Al = 1/19) improved catalytic performance for Fischer-Tropsch synthesis. In an investigation, we observed a pressure effect between 1 and 6 MPa over Ru/Mn/Al2O3, and this catalyst showed high CO conversion and high stability with time on stream at 4 and 6 MPa. At 4 MPa, CO conversion was estimated to be about 95%. The catalysts were characterized by BET surface area, BJH porosity, CO chemisorption, XRD, TPR, TEM and XPS. Characterization results suggest that a suitable ratio of manganese to aluminum in Ru/Mn/Al2O3 increases the concentration of active ruthenium metals and it can be associated with the formation of manganese chloride at the catalyst surface.