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CN-121972159-A - Preparation method and application of amorphous low-temperature denitration catalyst resistant to water poisoning and ammonium bisulfate poisoning

CN121972159ACN 121972159 ACN121972159 ACN 121972159ACN-121972159-A

Abstract

The invention relates to a preparation method and application of an amorphous low-temperature denitration catalyst resistant to water and ammonium bisulfate poisoning, belongs to the technical field of selective catalytic reduction catalysts, and solves the problem that the existing catalyst is difficult to simultaneously maintain high activity and high stability in a complex atmosphere containing liquid water and ammonium bisulfate deposition at ultralow temperature. The preparation method comprises the steps of mixing glacial acetic acid, absolute ethyl alcohol and ethylene glycol according to the volume ratio of (0.1-3) (1-5) (1) to obtain a first solution, adding a template agent and concentrated hydrochloric acid, stirring to obtain a second solution, adding precursors of manganese, titanium, cerium, niobium and an auxiliary agent, stirring to obtain a third solution, adding urea, stirring to obtain a fourth solution, adding a pore-expanding agent, stirring to obtain a fifth solution, reacting, washing and drying, reacting again, washing and drying, pre-calcining in an inert atmosphere, and calcining in air to obtain the amorphous denitration catalyst. The catalyst shows excellent denitration activity and stability under the conditions of liquid water and ammonium bisulfate.

Inventors

  • WANG YAN
  • ZHANG XIAOMIN
  • QU HAO
  • DING ZHIYONG
  • ZHANG CHENG
  • GUO XIN
  • KANG NA
  • WEI WEI
  • FENG WEI

Assignees

  • 包头稀土研究院

Dates

Publication Date
20260505
Application Date
20260409

Claims (10)

  1. 1. The preparation method of the amorphous low-temperature denitration catalyst resistant to water and ammonium bisulfate poisoning is characterized by comprising the following steps of: s1, uniformly mixing glacial acetic acid, anhydrous ethanol and ethylene glycol to obtain a first solution; s2, sequentially adding a template agent and concentrated hydrochloric acid into the first solution, and magnetically stirring at room temperature to obtain a second solution; s3, adding a manganese precursor, a titanium precursor, a cerium precursor, a niobium precursor and an auxiliary agent precursor into the second solution, and stirring until the precursors are uniformly mixed to obtain a third solution; s4, adding urea into the third solution, and vigorously stirring until the solution is clear and oily to obtain a fourth solution; s5, adding a pore-enlarging agent into the fourth solution, and magnetically stirring at room temperature until the pore-enlarging agent is completely dissolved to obtain a fifth solution; S6, transferring the fifth solution into a high-pressure reaction kettle with a polytetrafluoroethylene lining, sealing the high-pressure reaction kettle, and then placing the high-pressure reaction kettle in a constant-temperature oven for reaction to obtain a first product; S7, washing the first product to be neutral, and then placing the first product in a vacuum drying oven for drying to obtain dried powder; S8, ultrasonically dispersing the dried first product in ethanol to obtain a mixed solution, and transferring the mixed solution into a reaction kettle for constant-temperature reaction to obtain a second product; s9, centrifuging, washing and separating the second product, and drying in a vacuum drying oven to obtain a third product; And S10, placing the third product in a tube furnace, heating to a first designated temperature under an inert atmosphere for calcination, switching to an air atmosphere, and calcining at a second designated temperature to obtain the amorphous denitration catalyst.
  2. 2. The preparation method according to claim 1, wherein in the step S1, the volume ratio of glacial acetic acid, anhydrous ethanol and ethylene glycol is (0.1-3): (1-5): 1; In the step S2, the template agent is a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer P123, 0.9-3.5 g P123 is added into each 40-80 mL first solution, and/or, Adding 0.5-4.5. 4.5 g concentrated hydrochloric acid into the first solution every 40-80 mL.
  3. 3. The preparation method according to claim 1, wherein in the step S3, the precursor of manganese is one of manganese sulfate, manganese chloride, manganese nitrate, manganese acetate or manganese perchlorate; The precursor of the titanium is one of titanium tetrachloride, titanyl sulfate or titanate; the cerium precursor is cerium nitrate or cerium acetate; The precursor of niobium is one of niobium oxalate or niobium oxalate complex solution; the auxiliary precursor is one of soluble salts of vanadium, tungsten, molybdenum, terbium, yttrium or dysprosium.
  4. 4. The method according to claim 3, wherein the molar ratio of Mn, ce to Ti metal atoms in the manganese precursor, cerium precursor and titanium precursor is (0.4-1.3): 1 (1-5), and/or, In the niobium precursor and the titanium precursor, the mole ratio of Nb to Ti metal atoms is (0.02-0.05): 1, and/or, In the manganese precursor, the cerium precursor and the auxiliary agent precursor, the atomic mole ratio of the auxiliary agent metal element to the sum of Mn and Ce elements is (0.01-0.05): 1.
  5. 5. The method according to claim 1, wherein in step S4, the urea is added in an amount of 5 to 15g per 50 to 200mL g of the third solution.
  6. 6. The method according to claim 1, wherein in the step S5, the pore-expanding agent is an organic small molecule swelling agent, which is one of trimethylbenzene, n-decane, triethylbenzene, triisopropylbenzene, xylene or ethylbenzene, and/or, The mass ratio of the pore-expanding agent to the template agent is (0.5-2) 1.
  7. 7. The preparation method according to claim 1, wherein in step S6, the reaction temperature is 80-100 ℃ and the reaction time is 14-48 hours; in the step S7, the drying temperature is 80-100 ℃ and the drying time is 6-12h; in step S8, the power of the ultrasonic dispersion is 100-150W, the ultrasonic time is 15-30 min, and/or, The temperature of the constant-temperature reaction is 160-200 ℃ and the reaction time is 12-48h.
  8. 8. The process according to claim 1, wherein in step S9, the drying oven has a vacuum degree of 0.1 MPa or less, a drying temperature of 80 to 100℃and a drying time of 5 to 24 hours, and/or, In the step S10, the inert atmosphere is argon or nitrogen, the first designated temperature is 300-400 ℃, the calcination time is 4-8h, the second designated temperature is 400-600 ℃, and the calcination time is 1-6h.
  9. 9. An amorphous low temperature denitration catalyst resistant to poisoning by water and ammonium bisulfate, characterized by being prepared according to the preparation method of any one of claims 1 to 8.
  10. 10. Use of a low temperature denitration catalyst prepared by the preparation method as claimed in any one of claims 1 to 8 or a denitration catalyst as claimed in claim 9 in the denitration of flue gas containing liquid water and/or ammonium bisulfate.

Description

Preparation method and application of amorphous low-temperature denitration catalyst resistant to water poisoning and ammonium bisulfate poisoning Technical Field The invention relates to the technical field of selective catalytic reduction catalysts, in particular to a preparation method and application of an amorphous low-temperature denitration catalyst resistant to water and ammonium bisulfate poisoning. Background The technology of selective catalytic reduction (NH 3 -SCR) using ammonia as a reducing agent is the most widely used NO x treatment means at present. Along with the increasingly strict environmental protection requirements and the expansion of denitration application scenes, particularly aiming at non-electric industries such as steel, cement and the like and working conditions such as cold start of an aeroengine and a motor vehicle, the tail gas temperature is often lower than 200 ℃ and even 100 ℃, and extremely high requirements are provided for the low-temperature activity of a denitration catalyst. Research into low temperature SCR catalysts has become a current hotspot. Among them, mn-based catalysts are attracting attention due to their excellent low-temperature redox performance, and in particular Mn-Ce/TiO 2 series catalysts exhibit good catalytic activity in the temperature range of 100-250 ℃. Research shows that the introduction of Ce can effectively improve the N 2 selectivity and the sulfur resistance of the MnO x/TiO2 catalyst. In order to further improve the catalytic performance, researchers try various modification strategies including adding assistants such as Nb, W and the like, optimizing preparation methods and the like. However, denitration catalysts under ultra-low temperature (< 150 ℃) conditions still face significant challenges. First, the flue gas generally contains water vapor, and water molecules can be competitively adsorbed with reactants under the low-temperature condition, so that the activity of the catalyst is obviously reduced. More particularly, when SO 2 is present in the flue gas, it reacts with NH 3 to form Ammonium Bisulfate (ABS), which is readily deposited on the catalyst surface at low temperatures, covering the active sites and plugging the channels, resulting in irreversible deactivation of the catalyst. How to solve the problems of low-temperature activity, water resistance and ammonia bisulfate poisoning resistance simultaneously becomes a key bottleneck for restricting the application of ultra-low temperature SCR technology. The existing research on Mn-Ce-Ti-based catalysts relates to improvement of sulfur resistance, but the catalyst system with excellent water resistance and hydrogen sulfate ammonia poisoning resistance under ultralow temperature conditions still lacks an effective technical scheme. Particularly, the stability of the catalyst under the deposition conditions of liquid water and ammonium bisulfate is synchronously improved through amorphous structure design and specific preparation process regulation and control, which is not yet reported in a system. In summary, a novel SCR catalyst which has high activity, excellent water resistance and hydrogen sulfate ammonia poisoning resistance at ultralow temperature (< 150 ℃) is developed, and the novel SCR catalyst has important application value and significance. Disclosure of Invention In view of the above analysis, the present invention aims to provide a preparation method and application of an amorphous low-temperature denitration catalyst resistant to water and ammonium bisulfate poisoning, which are used for solving the problem that the existing low-temperature denitration catalyst is difficult to simultaneously maintain high denitration activity, excellent water stability and ammonium bisulfate poisoning resistance under ultralow temperature (< 150 ℃) conditions, especially in a complex atmosphere containing liquid water and Ammonium Bisulfate (ABS) deposition. The aim of the invention is mainly realized by the following technical scheme: The invention provides a preparation method of an amorphous low-temperature denitration catalyst resistant to water and ammonium bisulfate poisoning, which comprises the following steps: s1, uniformly mixing glacial acetic acid, anhydrous ethanol and ethylene glycol to obtain a first solution; s2, sequentially adding a template agent and concentrated hydrochloric acid into the first solution, and magnetically stirring at room temperature to obtain a second solution; s3, adding a manganese precursor, a titanium precursor, a cerium precursor, a niobium precursor and an auxiliary agent precursor into the second solution, and stirring until the precursors are uniformly mixed to obtain a third solution; s4, adding urea into the third solution, and vigorously stirring until the solution is clear and oily to obtain a fourth solution; s5, adding a pore-enlarging agent into the fourth solution, and magnetically stirring at room temperature until the por