Preparation of iron catalysts on reliable gamma alumina supports for Fischer-Tropsch synthesis

In addition to high activity, a reliable catalyst must exhibit resistance to thermal and mechanical stresses, which is achieved through high mechanical strength. In this work, nine samples of γ-alumina catalyst supports were prepared using the oil-drop method according to the Taguchi M9 design. To assess the reliability of the supports, all samples were evaluated through mechanical strength testing. Iron catalysts were then prepared on these supports via the wet impregnation method for use in Fischer-Tropsch synthesis. The results revealed that the catalyst prepared on the support with the following specifications: An Al/H ratio of 1.8, a hexamethylenetetramine solution concentration of 30 wt.%, an aging time of 12 hours, and a calcination temperature of 650°C, demonstrated good conversion in addition to relatively high mechanical strength (65 MPa), among the other samples. Finally, this reliable catalyst was evaluated in a reactor to determine the optimal conditions for achieving higher conversion and selectivity. The best results for CO conversion (61.9%) and C4 selectivity (4.1%) were obtained when the reaction operational conditions were T=270℃, P=3bar, GHSV=2153.40 h-1, and H2/CO=1. Highlights · Mechanical strength of gamma alumina support was evaluated to optimize performance catalyst. · Reliable catalysts should have both high mechanical strength and good catalytic properties. · Statistical analysis was used to optimize the operating conditions to achieve high CO conversion and product selectivity. · Models were validated using analysis of variance. · Higher selectivity was observed at lower temperatures and H2/CO molar ratios.