Development of precipitated iron Fischer-Tropsch catalysts. Quarterly technical progress report, 1 October 1995--31 December 1995

Two stirred tank slurry reactor tests of catalysts with nominal compositions 100 Fe/3Cu/4 K/2 Ca/16 SiO{sub 2} (run SB-3115) and 100 Fe/5 Cu/6 K/24 SiO{sub 2} (run SA-3155) were completed under task 5, The Effect of Source of Potassium and Basic Oxide Promoter, during the reporting period. Our assessment of the effects of addition of CaO promoter to our baseline catalysts B and C and the use of potassium silicate as the source of potassium promoter is as follows: in general, the addition of CaO promoter did not result in improved performance of the baseline catalysts; the use of CaO promoter may be best suited for operation at higher reaction pressures; the baseline procedure utilizing impregnation of Fe-Cu-SiO{sub 2} precursor with aqueous solution of KHCO{sub 3} as the source of potassium promoter is the preferred method of preparation; and the procedure which utilizes aqueous K{sub 2}SiO{sub 3} solution as the source of potassium also provides satisfactory results, and may be used as an alternative. A slurry reactor test (run SB-3425) was completed during the reporting period, following the catalyst pretreatment with H{sub 2} at 250{degrees}C for 4 h (Task 6. Pretreatment Effect Research). This pretreatment resulted in higher catalyst activity than our baseline procedure (H{sub 2} at 240{degrees}C for 2 h) but also higher methane and gaseous hydrocarbon selectivities (about 10-20% higher)