Catalytic behaviors of Co-Mn/TiO₂ catalysts for Fischer-Tropsch synthesis

The 15%(Co-Mn)/TiO₂,(Co/Mn=1/6) catalyst was prepared using fusion procedure and studied for the conversion of synthesis gas to C_2~4 olefins. The effects of calcination conditions and operation conditions such as the H₂/CO molar feed ratio at different temperatures, gas hourly space velocity (GHSV) and total reaction pressure on the catalytic performance of catalyst were investigated. The stability of the catalyst during 150 h at optimal operation conditions (t=250 ℃ H₂/CO=2/1, GHSV=1 500 h^-1 and p=0.3 MPa) has been investigated. It is found that this catalyst is high stable for production C_2~4 olefins. Characterizations of both precursors and calcined catalysts by powder X-ray diffraction, scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) specific surface area measurement and thermal analysis methods such as thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) show that the different preparation method influences the catalyst precursor structure and morphology.