Effect of reaction conditions on the product distribution during Fischer-Tropsch synthesis over an industrial Fe-Mn catalyst

The product distributions of Fischer-Tropsch synthesis (FTS) over an indust rial Fr-Mn catalyst are investigated under different reaction conditions in an integral fixed bed reactor. The typical non-ASF distributions of the FT S products are analyzed in terms of the competitive steps of the surface re actions- and the desorption- diffusion and re-adsorption of alkenes under t hese broad reaction conditions. It is found that alkene selectivities are s ignificantly higher than those for alkanes in a broad chain length range fr om C? to about Cro over the Fe-Mn catalyst under most reaction conditions. Under the operation conditions of the catalyst, alkenes with carbon number larger than 27 cannot be detected in the wax products. Consequently. the co ntents of heavy alkanes have a slight increase at about C-27. implying that primary alkenes with chain longer than C27 are dominantly hydrogenated to alkanes due to the long residence time of the products in the catalyst pore s. (C) 2001 Elsevier Science B.V. All rights reserved.