Technology development for cobalt F-T catalysts. Quarterly technical progress report No. 7, April 1, 1994--June 30, 1994

This project`s goal is the development of a commercially viable, cobalt-based Fischer-Tropsch (F-T) catalyst for use in a slurry bubble column (SBC) reactor. During the seventh quarter, significant progress in several areas has enabled us to make a number of important conclusions. Preliminary catalyst preparation of 3 batches of a Ru-promoted 20% Co/Al{sub 2}O{sub 3} has confirmed the similarity in catalysts prepared by Energy International and by Calsicat using the same procedure. This similarity was evident in both fixed and SBC reactor studies. All TiO{sub 2}-supported Co catalysts have been found to have poor F-T properties in both the fixed-bed and SBC reactors. These catalysts had been prepared following exactly the procedures given in the Exxon patents. One of the main problems in using TiO{sub 2} as a support is the fact that it has low surface area for supporting a 20 wt % Co catalyst. Another problem is that it does not seem to be robust enough for use in a SBC reactor. Ru promotion of Co/SiO{sub 2} does not have as dramatic an effect on catalyst activity as seen for Co/Al{sub 2}O{sub 3}. However, it does play a major role in maintaining higher activity (factor of 2 in the SBCR) when K is added to Co/Sr/SiO{sub 2}. Zr has been clearly shown by us to significantly enhance the F-T activity of Co/SiO{sub 2}. Such promotion is a basis for many of the Shell cobalt F-T patents. Latest results indicate that Zr also improves the activity of Co/Al{sub 2}O{sub 3}, although the methane selectivity is also slightly elevated. Finally, for our design of a ``benchmark`` Co F- T catalyst, research has now shown using both fixed-bed and SBC reactors that 0.3 wt % K is the optimum amount to use with Ru- promoted 20 wt % Co/Al{sub 2}O{sub 3}. This amount of K greatly improves higher hydrocarbon selectivity without causing an unacceptable loss of activity