Determination of the Deactivation Model of Iron-potassium/γ-Al2O3 Catalyst in a Fixed Bed Reactor

Catalyst activity and performance are the most important factors for selecting a catalyst in different processes. The Fischer-Tropsch synthesis is a very important synthesis that extensive action has been taken place to increase the activity of its catalysts (mainly cobalt and iron) in the recent century. Deactivation of the catalysts of the process is influenced by many factors, among which coking and sintering have come to be considered as key causes of the catalysts deactivation over time. Determination of the deactivation model for catalysts based on empirical data causes the catalyst activity and efficiency to be predictable, which, in turn, can significantly reduce the cost of construction and processing at industrial scale up. An Fe-K/Al2O3 catalyst was prepared by using an impregnation method in this research. Experimental data were measured in a fixed-bed tube reactor under low operating pressure (0.2 MPa) and high temperature (310 °C). By comparing the experimental data (in this study) with different models of deactivation, was obtained as the best model for the deactivation of Fe-K/Al2O3 catalyst that amounts of kd, aeq and m are 0.425, 0.459 and 1, respectively. Then, the experimental data obtained from this study were compared with those of the other references to evaluate the effectiveness of potassium promoter and alumina support on the parameters of the deactivation rate equation (as kd, aeq and m). It was found that alumina support at high operating pressures and low temperatures can reduce the deactivation rate of iron-based catalyst in the presence of K promoter.