Study on NH3-SCR performance and mechanism of Fe/Mn modified rare earth concentrate

Abstract

• In this paper, a green, environmentally friendly and efficient NH3-SCR catalyst was prepared using rare earth minerals. • This paper explores the relationship between transition metals Fe, Mn and rare earth concentrates and their influence on the catalytic performance of NH 3 -SCR. • In this paper, the synergistic catalytic reaction process between Ce, Fe and Mn on the surface of rare earth concentrates is explored. In this paper, the transition metals Fe and Mn are doped on the surface of rare earth concentrates by the impregnation method to prepare NH 3 -SCR catalyst active powder. SEM, XRD, BET, XPS, H 2 -TPR, NH 3 -TPD, NO-TPD, FTIR and other characterization methods are used to explore the surface properties and mechanism of rare earth concentrates doped with transition metals, and at the same time determine its catalysis in a simulated flue gas device performance. The results showed that the NO x conversion rate of Fe and Mn doped rare earth concentrates reached 94.8% at 200 °C. The specific surface area of the rare earth concentrate increases after Fe and Mn are doped. Fe and Mn are uniformly dispersed on the surface of the rare earth concentrate. The combined effect of Fe, Mn and the rare earth concentrate provides more weak acid sites for the reaction and promotes desorption of NO in the low temperature section. The redox performance of rare earth concentrates has also been greatly improved. Rare earth concentrates doped with Fe and Mn mainly follow the L -H mechanism in the low temperature section, and mainly follow the E-R mechanism in the high temperature section. In general, the introduction of transition metals Fe and Mn effectively improves the NH 3 -SCR catalytic activity of rare earth concentrates, and the rare earth concentrates themselves have good resistance and tolerance, which is useful for preparing NH 3 -SCR catalysts from natural minerals. It has important theoretical significance and practical value, and at the same time has a pioneering role in the application of Baiyun Obo rare earth minerals in industrial production. In this paper, the transition metals Fe and Mn are doped on the surface of rare earth concentrates by the impregnation method to prepare NH 3 -SCR catalyst active powder. SEM, XRD, BET, XPS, H 2 -TPR, NH 3 -TPD, NO-TPD, FTIR and other characterization methods are used to explore the surface properties and mechanism of rare earth concentrates doped with transition metals, and at the same time determine its catalysis in a simulated flue gas device performance. The results showed that the NO x conversion rate of Fe and Mn doped rare earth concentrates reached 94.8% at 200℃. The specific surface area of the rare earth concentrate increases after Fe and Mn are doped. Fe and Mn are uniformly dispersed on the surface of the rare earth concentrate. The combined effect of Fe, Mn and the rare earth concentrate provides more weak acid sites for the reaction and promotes desorption of NO in the low temperature section. The redox performance of rare earth concentrates has also been greatly improved. Rare earth concentrates doped with Fe and Mn mainly follow the L-H mechanism in the low temperature section, and mainly follow the E-R mechanism in the high temperature section. In general, the introduction of transition metals Fe and Mn effectively improves the NH 3 -SCR catalytic activity of rare earth concentrates, and the rare earth concentrates themselves have good resistance and tolerance, which is useful for preparing NH 3 -SCR catalysts from natural minerals. It has important theoretical significance and practical value, and at the same time has a pioneering role in the application of Baiyun Obo rare earth minerals in industrial production .