New shearing mechanical coating technology for synthesis of alumina-supported cobalt Fischer-Tropsch solid catalysts

This study presents a novel dry coating technology for Co/Al2O3 catalyst synthesis without solvents and heating treatment. Nano crystallized Co3O4 powders were mechanically coated onto gamma-Al2O3 using an advanced high-shear batch mixer "Picomix". The interaction between support and Co3O4 was produced by the shearing force of the blades in the jar and the van der Waal adhesion force. A uniform coating layer of a 1 mm to 3 mm thickness was observed. The diffusion of Co3O4 into gamma-Al2O3 pores did not occur, resulting in the formation of an "egg-shell" structure. Undesirable cobalt aluminate compounds that are difficult to reduce and inactive in Fischer-Tropsch synthesis were not generated. The dry coated catalysts exhibited comparable catalytic performance in Fischer-Tropsch synthesis to conventional chemical impregnated catalysts.