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CN-121972181-A - Iron-manganese composite oxide NH3SCR catalyst and method for producing same

CN121972181ACN 121972181 ACN121972181 ACN 121972181ACN-121972181-A

Abstract

The invention belongs to the technical field of environmental catalytic materials, and particularly relates to a ferro-manganese composite oxide NH 3 -SCR catalyst and a preparation method thereof. The catalyst consists of an active component, a forming auxiliary agent, an auxiliary active component and a carrier, wherein the catalyst comprises, by mass, 10% -20% of the active component, 5% -15% of the forming auxiliary agent, 0.5% -5% of the auxiliary active component and the balance of the carrier. The forming auxiliary agent comprises an inorganic adhesive and inorganic fibers, wherein the auxiliary active component is WO 3 , and the carrier is a ZrO 2 -TiO 2 bimetallic oxide carrier. The catalyst disclosed by the invention has excellent low-temperature catalytic activity, a wide active temperature window, high N 2 generation selectivity, outstanding hydrothermal aging resistance and good SO 2 poisoning resistance, and is suitable for industrial flue gas denitration treatment.

Inventors

  • SUN LIRUI
  • ZHANG LIDONG
  • CHEN CHAOYANG
  • XU WEIJIE
  • HE CHENLIANG

Assignees

  • 中国科学技术大学

Dates

Publication Date
20260505
Application Date
20260129

Claims (10)

  1. 1. An iron-manganese composite oxide NH 3 -SCR catalyst, which is characterized by comprising the following components in percentage by mass: 10-20% of active components, 5-15% of forming auxiliary agents, 0.5-5% of auxiliary active components and the balance of catalyst by weight of carriers; wherein the active component is a composite metal oxide of iron, manganese and cerium loaded on a carrier; In the composite metal oxide, the molar ratio of iron element to manganese element to cerium element is (1-3): (1-3): (0.1-0.5); The forming aid comprises an inorganic binder and inorganic fibers; the auxiliary active component is WO 3 ; The carrier is a ZrO 2 -TiO 2 bimetallic oxide carrier.
  2. 2. The iron manganese composite oxide NH 3 -SCR catalyst according to claim 1, wherein the catalyst comprises, in percentage by total mass of the catalyst: 12-18% of active components, 8-12% of forming auxiliary agents, 1-3% of auxiliary active components and the balance of catalyst.
  3. 3. The iron-manganese composite oxide NH 3 -SCR catalyst according to claim 1, wherein the molar ratio of iron element, manganese element and cerium element in the composite metal oxide is (1.8-2.2): (1.8-2.2): (0.25-0.35).
  4. 4. The iron-manganese composite oxide NH 3 -SCR catalyst according to claim 1, wherein the mass ratio of inorganic binder to inorganic fiber in the molding aid is (6-10) 1; The inorganic adhesive is at least one selected from silica sol and aluminum sol; the inorganic fibers include glass fibers.
  5. 5. The NH 3 -SCR catalyst of claim 1, wherein the molar ratio of titanium element to zirconium element in the composite carrier of ZrO 2 -TiO 2 bimetallic oxide is 1:1, and the ZrO 2 and TiO 2 are present in the form of TiZrO 4 solid solution.
  6. 6. A method for preparing the ferromanganese composite oxide NH 3 -SCR catalyst according to any one of claims 1 to 5, comprising the steps of: S1, preparing a ZrO 2 -TiO 2 bimetallic oxide composite carrier, namely preparing a precursor by adopting a coprecipitation method according to a proportion of titanium element to zirconium element of 1:1, and drying and calcining to obtain the ZrO 2 -TiO 2 bimetallic oxide composite carrier with a TiZrO 4 solid solution structure; S2, loading active components and auxiliary active components, namely adding the carrier prepared in the step S1 into impregnating solution containing soluble ferric salt, soluble manganese salt, soluble cerium salt and soluble tungsten salt for impregnation, and drying and calcining after the impregnation is finished to obtain a catalyst precursor; s3, molding, namely adding an inorganic adhesive and inorganic fibers in a molding auxiliary agent into the catalyst precursor prepared in the step S2, mixing, aging and then extruding and molding to obtain a catalyst blank; and S4, calcining and activating, namely drying the catalyst blank obtained in the step S3, calcining and activating in air atmosphere, and cooling to obtain the supported ferro-manganese composite oxide NH 3 -SCR catalyst.
  7. 7. The method for preparing a ferro-manganese composite oxide NH 3 -SCR catalyst according to claim 6, wherein in the step S1, the titanium source comprises titanium tetrachloride or titanium sulfate, the zirconium source comprises zirconium oxychloride, and the calcination condition is that the calcination is carried out at 450-650 ℃ for 3-6 hours.
  8. 8. The method for preparing a ferro-manganese composite oxide NH 3 -SCR catalyst according to claim 6, wherein in step S2, the soluble iron salt comprises ferric nitrate, the soluble manganese salt comprises manganese nitrate, the soluble cerium salt comprises cerium nitrate, and the soluble tungsten salt comprises ammonium metatungstate hydrate, and the calcination condition is that the calcination is performed at a temperature of 350-550 ℃ for 3-5 hours.
  9. 9. The method for preparing a ferro-manganese composite oxide NH 3 -SCR catalyst according to claim 6, wherein in the step S3, the mixing time is 30-90min, and the aging time is 12-24h.
  10. 10. The method for preparing a ferro-manganese composite oxide NH 3 -SCR catalyst according to claim 6, wherein in the step S4, the condition of calcination activation is that the temperature is raised to 450-600 ℃ at a temperature rising rate of 1-5 ℃ per minute, and the temperature is kept for 4-8 hours.

Description

Iron-manganese composite oxide NH 3 -SCR catalyst and preparation method thereof Technical Field The invention belongs to the technical field of environmental catalytic materials, and particularly relates to a ferro-manganese composite oxide NH 3 -SCR catalyst and a preparation method thereof. Background With the rapid development of industrialization and urbanization, nitrogen oxide (NO x) emissions have become an important source of atmospheric pollution, severely threatening the ecological environment and human health. The SCR (selective catalytic reduction) technology is one of the most effective NO x removal methods at present, wherein the NH 3 -SCR technology which takes NH 3 as a reducing agent is widely applied to the field of fixed source flue gas treatment of coal-fired power plants, industrial boilers and the like due to high denitration efficiency and good selectivity. The core of the technology is the high-efficiency catalyst, and the performance of the catalyst directly determines the efficiency, the running cost and the application range of the denitration system. Among the numerous denitration materials, the ferro-manganese composite oxide becomes a research hot spot of the non-vanadium-based low-temperature SCR catalyst in recent years due to the excellent low-temperature catalytic activity, environmental friendliness and relatively low cost, and has the potential of replacing the traditional vanadium-titanium catalyst. The existing preparation and modification technical routes of the ferro-manganese composite oxide catalyst mainly concentrate on the aspects that firstly, the ferro-manganese composite oxide catalyst is synthesized through a common method such as a coprecipitation method, a sol-gel method and the like, the activity of the ferro-manganese composite oxide catalyst is highly dependent on Fe/Mn ratio, precursor types and roasting temperature, but the problems of uneven dispersion of active components, limited specific surface area and insufficient thermal stability of high temperature water are commonly caused, secondly, a carrier loading strategy (such as TiO 2, a carbon material, a molecular sieve and the like) is adopted to improve the dispersity and the mechanical strength, however, the interaction mechanism between a carrier and the active components is complex, the improper combination can cause the active sites to be covered or generate adverse chemical actions, the intrinsic activity is reduced, and thirdly, the oxidation-reduction performance and the surface acidity are regulated through the introduction of third or even fourth metal elements (such as Ce, cu, co, zr and the like), and the route achieves a certain progress in improving the low-temperature activity or widening the activity temperature window, but tends to be complicated in the preparation process, the cost is increased, and the segregation or phase change element can exist in the long-term operation, so that the activity is degraded. In addition, most of the prior researches focus on ideal condition evaluation in a laboratory, the capability of the catalyst for resisting SO 2 and H 2 O poisoning in actual flue gas is still a common bottleneck limiting engineering application of the catalyst, and the prior modification means still have significant defects in long-acting sulfur resistance and water resistance. Therefore, the ferromanganese composite oxide NH 3 -SCR catalyst which has excellent low-temperature activity, good hydrothermal stability and outstanding poisoning resistance and is simple and controllable in preparation process is developed, and has important practical significance and application requirements. Disclosure of Invention The invention aims to overcome the defects of the prior art, provides a ferro-manganese composite oxide NH3-SCR catalyst and a preparation method thereof, and solves the problems that the existing ferro-manganese-based low-temperature NH 3 -SCR catalyst is generally narrow in active temperature window, poor in hydrothermal stability, insufficient in sulfur resistance and water resistance, difficult to stably operate for a long time under actual complex smoke conditions and the like. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: 1. An iron-manganese composite oxide NH 3 -SCR catalyst, comprising, in percent by total mass of the catalyst: 10-20% of active components, 5-15% of forming auxiliary agents, 0.5-5% of auxiliary active components and the balance of catalyst by weight of carriers; wherein the active component is a composite metal oxide of iron, manganese and cerium loaded on a carrier; In the composite metal oxide, the molar ratio of iron element to manganese element to cerium element is (1-3): (1-3): (0.1-0.5); The forming aid comprises an inorganic binder and inorganic fibers; the auxiliary active component is WO 3; The carrier is a ZrO 2-TiO2 bimetallic oxide carrier. Preferably, the catalyst comprises, in