The synthesis of attrition resistant slurry phase iron Fischer-Tropsch catalysts

We describe the evolution of catalyst microstructure as a precipitated Fe-C u catalyst precursor is transformed into an attrition resistant Fischer-Tro psch (F-T) catalyst. The precipitated Fe-Cu catalyst, as-prepared, is weak compared to the same catalyst that was spray-dried, but without a binder. S pray-drying improves the attrition resistance of the catalyst. Ultrasonic f ragmentation was used in this work to measure the attrition resistance of t he slurry phase catalysts. Both catalysts, after ultrasonication, produce f ine particles below 5 mu m, which could cause filtration problems in slurry F-T reactors. The addition of silica as the binder improved the catalyst's attrition resistance with negligible generation of fine particles below 5 mu m. Cross-section TEM of the SiO2-containing Fe F-T catalyst shows that t he crystallized Fe particles with an average particle diameter of 80 nm are uniformly distributed within a silica binder. This study provides insight into the catalyst microstructure that leads to improved attrition resistanc e in Fe F-T catalysts. (C) 2000 Elsevier Science B.V. All rights reserved.