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CN-121972215-A - Double-mechanism coupling antitoxic low-temperature denitration catalyst and preparation method thereof

CN121972215ACN 121972215 ACN121972215 ACN 121972215ACN-121972215-A

Abstract

The invention relates to the technical field of low-temperature denitration catalysts, in particular to a double-mechanism coupling antitoxic low-temperature denitration catalyst and a preparation method thereof, wherein the double-mechanism coupling antitoxic low-temperature denitration catalyst is prepared by mixing, aging, extrusion molding, drying and roasting modified catalyst powder, molding auxiliary agent and deionized water, the modified catalyst powder is obtained by loading a gradient composite carrier with double active components and a double antitoxic modifier. The low-temperature flue gas denitration catalyst has the characteristics of good low-temperature activity and strong composite poisoning resistance, has good mechanical strength and wear resistance, can meet the mechanical performance requirements of industrial low-temperature flue gas denitration application, and can be widely applied to low-temperature flue gas denitration treatment in industries such as coal-fired power plants, steel, coking, garbage incineration and the like.

Inventors

  • YANG CHENG
  • LI FUYONG
  • ZHANG WENBIN
  • PANG YANG
  • ZHANG CHENG
  • TAO JIN
  • ZHAO HUAN

Assignees

  • 新疆中泰国信节能环保有限公司

Dates

Publication Date
20260505
Application Date
20260226

Claims (10)

  1. 1. The double-mechanism coupling antitoxic low-temperature denitration catalyst is characterized by comprising 75 to 82 parts of modified catalyst powder, 15 to 22 parts of forming auxiliary agent and 16 to 25 parts of deionized water in parts by weight, wherein the modified catalyst powder is obtained by carrying out double-active component loading and double-antitoxic modifier loading on a gradient composite carrier, the gradient composite carrier is formed by compounding hollow microspheres of double-rare-earth element doped titanium dioxide and mesoporous SAPO-18 molecular sieve in a mass ratio of 3.5 to 5.5:1, and the hollow microsphere raw materials of the double-rare-earth element doped titanium dioxide comprise nano titanium dioxide, neodymium oxide and ytterbium oxide in a mass ratio of 50:1.5 to 2.5:1.0 to 2.0.
  2. 2. The dual-mechanism coupling antitoxic low-temperature denitration catalyst according to claim 1, wherein the dual-active component comprises a first active component and a second active component, wherein the first active component comprises manganese nitrate, cerium nitrate and samarium nitrate in a mass ratio of 15 to 20:5.0 to 7.5:2 to 4, the second active component comprises copper nitrate and manganese chloride in a mass ratio of 3:3 to 6, and/or the dual-antitoxic modifier comprises niobium pentoxide and titanium nitride in a mass ratio of 2 to 3:0.8 to 1.0.
  3. 3. The dual-mechanism coupling antitoxic low-temperature denitration catalyst of claim 1 or 2, wherein the forming aid is compounded by alumina fiber, hydroxypropyl methylcellulose and silica sol with a mass ratio of 1.5-2.5:0.5-1.0:0.5-1.5.
  4. 4. The dual-mechanism coupling antitoxic low-temperature denitration catalyst of claim 1, 2 or 3, wherein the modified catalyst powder is obtained by the following method: s1, preparation of gradient composite carrier S11, mixing the required amounts of nano titanium dioxide, neodymium oxide and ytterbium oxide, then placing the mixture in a potassium hydroxide solution, stirring and performing ultrasonic dispersion, and then heating and reacting to obtain a product; S12, cooling, washing and drying the product to obtain hollow microspheres doped with the double rare earth elements and titanium dioxide, and mixing the hollow microspheres doped with the double rare earth elements and the mesoporous SAPO-18 molecular sieve to obtain a gradient composite carrier; S2, double active component load S21, dissolving manganese nitrate, cerium nitrate and samarium nitrate in dilute nitric acid to prepare a first active component solution, and dissolving copper nitrate and manganese chloride in ethanol to prepare a second active component solution; S22, placing the gradient composite carrier in a first active component solution for ultrasonic impregnation, drying to obtain a gradient composite carrier loaded with a first active component, placing the gradient composite carrier loaded with the first active component in a second active component solution for secondary impregnation, and drying and roasting to obtain a double active component loaded intermediate; S3, loading double-antitoxic modifier S31, dissolving niobium pentoxide and titanium nitride in deionized water, and performing ball milling and mixing to obtain a suspension; S32, immersing the intermediate loaded by the double active components into the suspension, stirring, drying and roasting to obtain the modified catalyst powder.
  5. 5. The dual-mechanism coupling antitoxic low-temperature denitration catalyst of claim 4, wherein in step S11, the mass concentration of potassium hydroxide solution is 5mol/L to 10mol/L, the time is 2.5h to 3.5h when stirring, the ultrasonic dispersion time is 1.0h to 2.0h, the reaction time is 45h to 48h, the reaction temperature is 125 ℃ to 135 ℃, or/and in step S12, the washing is carried out until the pH is 7, the drying temperature is 90 ℃ to 100 ℃ when drying, and the silicon-aluminum ratio of the mesoporous SAPO-18 molecular sieve is 28:1.
  6. 6. The dual-mechanism coupled anti-poison low-temperature denitration catalyst according to claim 4 or 5, wherein in step S21, the mass concentration of the first active component solution is 0.7mol/L to 2.3mol/L, the mass concentration of the second active component solution is 0.5mol/L to 1.8mol/L, or/and in step S22, the time of ultrasonic impregnation and re-impregnation is 1h to 3h, the drying time is 8h to 10h, the drying temperature is 60 ℃ to 70 ℃ when drying, the drying time is 8h to 12h, the drying temperature is 100 ℃ to 110 ℃, the roasting time is 4.5h to 5.0h, and the roasting temperature is 460 ℃ to 500 ℃.
  7. 7. The dual-mechanism coupling antitoxic low-temperature denitration catalyst according to claim 4,5 or 6, wherein in step S31, ball milling mixing time is 2.0-2.5 h, or/and in step S32, stirring time is 1.0-1.5 h, drying temperature is 105-115 ℃ and drying time is 5.5-6.5 h, roasting temperature is 450-480 ℃ and roasting time is 3.0-3.5 h.
  8. 8. The dual-mechanism coupling antitoxic low-temperature denitration catalyst according to any one of claims 1 to 7, which is characterized by being obtained by mixing modified catalyst powder, a forming additive and deionized water, and then mixing, aging, extrusion molding, drying and roasting the mixture to obtain the dual-mechanism coupling antitoxic low-temperature denitration catalyst.
  9. 9. The dual-mechanism coupling antitoxic low-temperature denitration catalyst according to claim 8, wherein the mixing time is 1.0 to 1.5 hours, the aging time is 16 to 18 hours, the drying temperature is 110 to 120 ℃ when drying, the drying time is 12 to 14 hours, the roasting temperature is 550 to 580 ℃ when roasting, and the roasting time is 6.0 to 6.5 hours when mixing.
  10. 10. A method for preparing the dual-mechanism coupling antitoxic type low-temperature denitration catalyst according to any one of claims 1 to 7 and 9 is characterized by comprising the steps of mixing modified catalyst powder, a forming additive and deionized water, and obtaining the dual-mechanism coupling antitoxic type low-temperature denitration catalyst after mixing, ageing, extrusion forming, drying and roasting.

Description

Double-mechanism coupling antitoxic low-temperature denitration catalyst and preparation method thereof Technical Field The invention relates to the technical field of low-temperature denitration catalysts, in particular to a double-mechanism coupling antitoxic low-temperature denitration catalyst and a preparation method thereof. Background At present, a Selective Catalytic Reduction (SCR) technology is a mainstream smoke denitration technology, however, the existing low-temperature denitration catalyst has a plurality of technical problems that firstly, the activity of the traditional low-temperature catalyst (180 ℃ to 300 ℃) is insufficient in a low-temperature region and is easily poisoned by composite pollutants such as SO 2、H2 O, alkali metal (K) and heavy metal (Pb), SO that the service life of the low-temperature denitration catalyst is greatly shortened, secondly, the active components adopt a single distribution mode, the low-temperature activity and the antitoxic performance are difficult to be compatible, the antitoxic mechanism is single, the design is aimed at a certain pollutant, the industrial low-temperature smoke working condition of coexistence of multiple pollutants cannot be adapted, and thirdly, the preparation technology relies on a single impregnation method and a coprecipitation method, SO that the accurate regulation of the active components and the optimization of a carrier structure are difficult to be realized. For example, chinese patent publication No. CN114904509B discloses a wide temperature range denitration catalyst and a preparation method thereof, the patent discloses that the catalyst comprises, based on 100% of the total mass of the catalyst, 0.8-5% by weight of main active component, 0.1-2% by weight of auxiliary active component, 1-8% by weight of acid auxiliary agent, 0.1-1.3% by weight of modifying auxiliary agent, 2-7% by weight of reinforcing agent and 78-94.7% by weight of composite carrier, wherein in the surface layer region of the catalyst, the content of the main active component is 0.9-7% by weight, the content of the auxiliary active component is 0.2-4% by weight, the content of the acid auxiliary agent is 1.2-9.5% by weight, and the content of the modifying auxiliary agent is 0.2-3.5% by weight, based on the total mass of the surface layer region of the catalyst. The wide-temperature denitration catalyst provided by the invention has the advantages of high wide-temperature denitration efficiency and low SO 2 oxidation rate. The patent discloses a surface active component enrichment type catalyst which adopts Fe-Ce modified antitoxic and single impregnation technology, and has low-temperature activity initial temperature of 180 ℃ and limited composite poisoning resistance. The Chinese patent document with publication number CN109513451A discloses a preparation method and application of a wide-temperature high-efficiency nontoxic SCR catalyst, the general formula of which is AxFe (3-x)O4, wherein x is less than or equal to 1, and A is one or a combination of titanium, magnesium, manganese and nickel elements. The wide-temperature nontoxic iron-based denitration catalyst is prepared by adopting the coprecipitation method, so that the defects of low denitration efficiency, narrow temperature window, poor stability, poor selectivity and the like of the traditional Fe-based SCR catalyst are effectively overcome while the cost is reduced. Under the condition that the temperature is 200-450 ℃, the airspeed reaches 3,000h -1 -200,000 h -1, and the nitrogen oxide flue gas contains SO 2 of 0mg/m 3 -2700 mg/m 3 and nitrogen oxide flue gas of 0-20% of water vapor, the denitration efficiency of the catalyst is stabilized to be more than 90%, the selectivity of N 2 is stabilized to be more than 95%, and the catalyst is suitable for controlling the emission of nitrogen oxides of fixed source flue gas of thermal power plants, coking plants and the like. The patent takes Fe-based spinel as an active component, takes the traditional V-W-Ti as a carrier, has the low-temperature denitration efficiency of less than 90 percent, and can only realize a single sulfur toxin resisting function. The Chinese patent document with the publication number of CN114433123B discloses a monolithic honeycomb catalyst for low-temperature SCR denitration, and a preparation method and application thereof, wherein the monolithic honeycomb low-temperature SCR denitration catalyst comprises a carrier and an active component, the carrier is a doped titanium dioxide nanotube doped with metal oxide, the active component is a mixture of MnO x and FeO y, x is 1-2, y is 1-1.5, the molar ratio of element Mn to element Fe in the active component is (10-0.1): 1, and the catalyst is a monolithic honeycomb catalyst. The carrier, the active component precursor and the forming auxiliary agent are subjected to dry mixing, kneading, mixing, aging, extrusion, drying and roasting to prepare the integral honeycomb de