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

The product distributions of Fischer–Tropsch synthesis (FTS) over an industrial Fe-Mn catalyst are investigated under different reaction conditions in an integral fixed bed reactor. The typical non-ASF distributions of the FTS products are analyzed in terms of the competitive steps of the surface reactions, and the desorption, diffusion and re-adsorption of alkenes under these broad reaction conditions. It is found that alkene selectivities are significantly higher than those for alkanes in a broad chain length range from C2 to about C20 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 contents of heavy alkanes have a slight increase at about C27, 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 pores.