Analysis of CO catalytic oxidation by Pt-loading catalyst and Ce-doped Fe₂O₃

The iron ore sintering flue gas contains a relatively high CO concentration (volume fraction of 0.5%‒2%); therefore, it is of great significance to remove CO. To study the catalytic effect of different catalysts, typical Pt-supported catalyst and Ce-doped Fe₂O₃ catalyst were prepared by impregnation, and their components were analyzed by X-ray fluorescence. The activity results show that different initial CO concentrations, flue gas temperature, and water vapor volume fraction have a great influence on the removal efficiency of CO catalytic oxidation. When there is no water vapor in the flue gas, the CO removal efficiency of the two catalysts is over 60%. When the reaction temperature is 180 ℃ and the water vapor volume fraction is 11.7%, the CO conversion efficiency of the Pt-supported catalyst is 63.9%, but the CO conversion efficiency of the Ce-doped Fe₂O₃ catalyst is only about 34.9%. Furthermore, the results show that the Pt-supported catalyst has a better water resistance in the range of 180‒300 ℃. If the reaction temperature is higher, the increase in water vapor volume will have a more negative impact on the catalytic efficiency of both catalysts. For example, when the volume fraction of water vapor increases from 0 to 27.1%, the catalytic efficiency of the Pt-supported catalyst drops from 73.9% to 62.3%, which decreases much more compared to the case of 180 ℃. In addition, the sulfur resistance of the two catalysts was also tested. The Ce-doped Fe₂O₃ catalyst is more resistant to SO₂, when there is no water vapor. However, when SO₂ and water vapor exist at the same time, the Pt-supported catalyst has better sulfur resistance. Therefore, during the actual sintering process, it is recommended to adopt efficient desulfurization measures and arrange the water absorption layer in order to reduce the negative impacts on catalysts.