Study On Preparation And Properties Of Nano-Iron-Zirconium Based SCR Catalyst

Nitrogen oxides（NO_x）emission control has become an important air pollution control task.Iron and steel enterprises are one of the main sources of NO_x emissions.50%of the nitrogen oxide emissions originate from the sintering process.In order to meet the increasingly stringent nitrogen oxides emission standard,it is urgent to develop a denitration catalyst suitable for sintering flue gas.The iron based catalyst has good denitrification and sulfur resistance properties,but the temperature window of the iron base catalyst can not meet the conditions of the sintering flue gas and the performance of thermal stability is relatively poor.In this paper,the catalyst supports are prepared by adjusting preparation process and active component formula.The preparation process of denitration property with low temperature window was obtained,meanwhile possess good sulfur resistance and suitable sintering flue gas conditionsThe effect of different process conditions on the performance of catalyst support was studied,including aging time,sodium hydroxide concentration and hydrothermal temperature.The appropriate aging time is 72h,the concentration of sodium hydroxide is 2M,and the hydrothermal temperature is 170°C.The effect of different iron and zirconium ratio on the performance of the catalyst support was studied,the suitable iron and zirconium ratio was 9:1.The crystal structure of the catalyst support was analyzed.It was found that all the components of the iron zirconium support were distributed uniformly,iron zirconium could co-nucleate to form iron zirconium solid solution,the best denitrification rate is 60%.The thermal stability of iron based support with zirconium and without zirconium was compared.The result shows that zirconium can effectively improve the thermal stability of the support.The Mn/FeZr catalyst prepared by the co precipitation impregnation method with a94%denitration rate at 225°C.The effect of Ce,V and Co components on the performance of Mn/FeZr on catalyst is studied.The correlation detection analysis shows that Co can effectively improve the rate of low temperature denitrification,V can effectively improve the resistance to sulfur poisoning.Ce is beneficial to improve the ability of low temperature denitrification and sulfur poisoning of the catalyst.Therefore,under the same condition,Ce is the best choice.The reaction mechanism of X-Mn/Fe-Zr（X=Ce,V,Co）denitration catalyst has been studied.It is found that there exists L-H mechanism and E-R mechanism in the system catalyst.The reaction process of the Ce-Mn/Fe-Zr catalyst mainly follows the L-H mechanism,that is,the reductant NH₃ is oxidized to the nitro species on the surface of the catalyst mainly by adsorption,and then reacts with the adsorbed nitrogen oxide to achieve the denitrification process...