Development of Fe Fischer-Tropsch catalysts for slurry bubble column reactors

The effect of two binder systems - a silica-based system and a silica-kaolin-clay-phosphate-based system - on a doubly promoted Fischer-Tropsch (FT) synthesis iron catalyst (100Fe/5Cu/4.2K) was studied. The catalysts were prepared by coprecipitation, followed by binder addition and spray drying at 270 degrees C in a 1 m diameter, 2 m tall spray dryer. The binder silica content was varied from 0 to 20 wt.%. A catalyst with 12 wt.% binder silica was found to have the highest attrition resistance. The FT activity and selectivity of this catalyst are better than a Ruhrchemie catalyst at 270 degrees C and 1.48 MPa. The addition of precipitated silica or kaolin to catalysts containing 10-12 wt.% binder silica decreases attrition resistance and increases methane selectivity. Based on the experience gained, a catalyst has been successfully spray dried in 500 g quantity. This catalyst showed 95% CO conversion over 125 h of testing at 270 degrees C, 1.48 MPa, and 2 NL/g-cat/h and had less than 4% methane selectivity. Its attrition resistance was one of the highest among the catalysts tested. (C) 2000 Elsevier Science B.V. All rights reserved.