FTS fuels production over different Co/SiC catalysts

The technical feasibility for Fischer–Tropsch synthetic fuels production over different cobalt/SiC catalysts was studied. Silicon carbide-supported catalysts were prepared by means of incipient wetness impregnation (IWI) and characterized by N2 adsorption/desorption, acid/base titrations, XRD, TEM, TPR and pulse oxidation techniques. The bench scale catalytic performance was examined at a total pressure of 20 bar, a temperature range between 220 and 250 °C, a space velocity (GHSV) of 6000 N cm3 g−1 h−1 and using syngas with H2/CO molar ratio equal to 2. For SiC-supported catalysts, the use of a certain amount of calcium as promoter resulted in a higher basicity and a slight higher cobalt dispersion. Furthermore, particle size and the degree of reduction were found to be directly influenced by the cobalt loading. A maximum extent of reduction was found at 12–15 wt.% cobalt with little dependence on the addition of promoter. Catalytic activity provided promising Fischer–Tropsch performance with C5+ selectivity values higher than 90% in all the cases and especially on promoted catalysts (higher than 95%). In addition, promoted catalysts shifted C5+ hydrocarbon product distribution to higher molecular weight demonstrating that different commercial synthetic fuels formulations (gasoline to diesel) can be provided by modifying mCo-nCa/SiC catalyst composition.