Wustite-based iron catalyst for ammonia synthesis
National Petrochemical Company, Petrochemical Research and Technology Company, Catalyst Research Group, Tehran, Iran
Wustite-based iron catalyst is used as an ammonia synthesis catalyst. It is prepared by fusion method. The raw materials including magnetite, iron and promoters (aluminium, calcium and potassium) are mixed and then fused together. After then they have been crushed and sieved as 16-18 mesh sizes. The difference between the magnetite and the wustite samples is the main phase of iron, and the amount of the promoters are same as each other. The samples are characterized by N2 adsorption/desorption, XRD and EDS-Mapping techniques. The Fe2+/Fe3+ ratio in the samples have been measured by chemical titration. The activity tests are carried out in a fixed-bed reactor at T=430 °C, p=30 bar, catalyst loading: 1 g and H2/N2 (3/1): 120 Nml/min. The effluent gas is analyzed by an online GC. Results show that the activity of the wustite catalyst for ammonia synthesis is higher than the magnetite catalyst under the reaction conditions. It is more reducible than magnetite. The distribution of K2O as an electronic promoter in wustite phase is better than magnetite phase and it causes high activity of wustite catalyst.