Improving the attrition resistance of slurry phase heterogeneous catalysts

Slurry phase heterogeneous catalysts for processes such as Fischer–Tropsch (F–T) synthesis must exhibit a high degree of attrition resistance. The precipitated Fe–Cu catalyst used for F–T synthesis is quite weak in its as-prepared state. Spray-drying yields spherical particles which show some improvement in attrition resistance. However, the formation of fines (<5 μm) in this powder shows that it is not suitable as a slurry phase catalyst. In this paper, we report on the use of a silica binder to improve the strength of spray-dried agglomerates. The attrition resistance was measured using ultrasonic fragmentation followed by sedigraph particle size analysis. The attrition strength of the iron oxide catalyst agglomerates was compared to that of a commercial alumina powder, which was used as a reference material. The role of calcination (before or after spray-drying) and the method of silica binder addition (before or after spray-drying) was investigated.