Activation studies with a promoted precipitated iron Fischer-Tropsch catalyst

The effect of reductant type (CO, H2, or H2/CO = 0.68), activation temperature (250, 280, and 310 °C), duration (8 and 24 h), and pressure (0.1 and 1.48 MPa) on the activity and selectivity of a promoted precipitated iron catalyst (100Fe/3Cu/0.2K) was studied in a fixed bed reactor. It was found that activation parameters have a strong effect on the catalyst behaviour during Fischer-Tropsch (FT) synthesis at 250°C, 1.48 MPa, 2 nL/g of catalyst/h, and H2/CO = 1. Activations in CO led to catalysts that had higher initial activity and better selectivity (less methane and other light hydrocarbons) than H2 activated catalysts. However, the activity of CO-reduced catalysts declined with time on stream, whereas the activity of H2-reduced catalysts remained constant or increased during 120 h of testing.