Development of Precipitated Iron Fischer-Tropsch Catalysts

Four (alumina or silica) supported catalysts were prepared by conventional impregnation of two commercial supports (silica - Davison grade 952; and alumina - Vista B). Nominal compositions (on mass basis) of synthesized catalysts are: (1) 100 Fe/5 Cu/6 K/139 SiO{sub 2} (2) 100 Fe/10 Cu/6 K/134 SiO{sub 2}, (3) 100 Fe/5 Cu/6 K/139 Al{sub 2}0{sub 3} and (4) 100 Fe/10 Cu/6 K/134 Al{sub 2}0{sub 3}. The corresponding weight % of iron (as metal) in the prepared catalysts is about 33.8%. Reduction behavior of the four supported catalysts was studied by both temperature programmed and isothermal reduction in hydrogen, and by isothermal reduction in CO at 280{degrees}C. Also, two precipitated promoted iron catalysts containing aluminum oxide as a binder, were reduced isothermally in the TGA unit with hydrogen at 240{degrees}C and 280{degrees}C. One of the two alumina containing catalysts (100 Fe/5 Cu/4.2 K/20 Al{sub 2}0{sub 3}) was tested in a slurry reactor (run SA-0097), and catalyst samples withdrawn from the reactor at various times on stream were characterized by XRD to determine bulk iron phases in the catalyst. Two slurry reactor tests were completed during this quarter. The first test (SA-0097) was conducted with alumina containing catalyst with nominal composition 100 Fe/5 Cu/4.2 K/20 Al{sub 2}0{sub 3}, which was synthesized previously in our laboratory (DOE Contract DE-AC22-85PC8001 1). The second test (SB-0627) was conducted with one of the silica supported catalysts which was prepared during this quarter: 100 Fe/5 Cu/6 K/139 SiO{sub 2} (Davison silica, grade 952). The performance of these two catalysts was inferior in comparison to our catalysts B (100 Fe/5 Cu/6 K/24 SiO{sub 2}) and C (100 Fe/3 Cu/4 K/16 SiO{sub 2}). Activity of these two catalysts was lower, catalyst deactivation rate was faster, and gaseous hydrocarbon selectivities were higher in comparison to the baseline catalysts B and C