Fischer-Tropsch Synthesis: a Comparison of Iron and Cobalt Catalysts
Mingsheng Luo, Shiqi Bao, Robert A. Keogh, Amitava Sarkar, Gary Jacobs, and Burtron H. Davis. Center for Applied Energy Research, University of Kentucky, 2540 Research Park Drive, Lexington, KY 40511-8479
Of the potential elements for a Fischer-Tropsch catalyst, only iron and cobalt have sufficient supply and properties to be considered for a commercial operation today. The early interest in Germany focused on the cobalt catalyst and this was the only metal used commercially through 1945. Following 1945, iron catalysts were utilized in commercial operations in both the United States and South Africa. The discovery of large quanties of oil in the Middle East led to the abandonment of the U.S. effort but Sasol successfully used iron catalysts to expand their production to about 150,000 bbl/day today. PetroSA currently produces about 35,000 bbl/day using iron catalysts. On the other hand, Shell utilizes cobalt catalysts to produce about 15,000 bbl/day and the Sasol operation in Qatar will also utilize a cobalt catalyst. Today the perception is that, at least for a natural bas based plant, cobalt is the preferred catalyst. Based on our lab data, we will compare the two catalysts on the basis of their catalytic activity and lifetime as well as their production of undesirable gaseous products (CO2 + C1-C4 alkanes) and high-molecular weight products.