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CN-121972211-A - Arsenic-resistant high-temperature-resistant zeolite-based denitration catalyst and preparation method thereof

CN121972211ACN 121972211 ACN121972211 ACN 121972211ACN-121972211-A

Abstract

The invention belongs to the technical field of catalysts and fine chemical engineering, and particularly relates to an arsenic-resistant and high-temperature-resistant zeolite-based denitration catalyst and a preparation method thereof. According to the invention, a Pt salt and an-NH 2 group in amino acid are used for carrying out a complexing reaction to generate a Pt-amino acid complex, the-COOH group in the complex has a good binding effect with a silicon source and an aluminum source, the Pt-amino acid complex is added into a zeolite gel precursor solution, the silicon source and the aluminum source can grow around the Pt-amino acid complex under the induction effect of a template agent in the later stage, and finally Pt is inlaid in ZSM-5 zeolite crystal to form the Pt@ZSM-5 catalytic material. The zeolite-based denitration catalyst prepared by the invention has excellent arsenic resistance and high-temperature denitration activity.

Inventors

  • WANG QUANHUA
  • ZHANG XIN
  • GUO LIXING
  • YUE YANWEI
  • LIU KAIMING
  • ZONG YUHAO
  • WANG HU
  • CHI YUCHEN
  • LI JINKE
  • XIE XINGXING

Assignees

  • 大唐南京环保科技有限责任公司

Dates

Publication Date
20260505
Application Date
20260105

Claims (10)

  1. 1. A method for preparing a zeolite-based denitration catalyst, comprising the steps of: s1, dissolving platinum salt and amino acid in water to obtain a solution A; s2, dissolving a silicon source and an aluminum source in water to obtain a solution B; S3, mixing the solution A and the solution B to form initial gel, and drying and grinding the initial gel to obtain xerogel powder; and S4, mixing the xerogel powder with a structure directing agent, crystallizing, and washing, drying and roasting the obtained crystallized product to obtain the zeolite-based denitration catalyst.
  2. 2. The method according to claim 1, wherein the molar ratio of the platinum salt to the amino acid in step S1 is 0.01 to 0.9; Preferably, the platinum salt is selected from one or more of chloroplatinic acid, sodium hexachloroplatinate and potassium hexachloroplatinate; Preferably, the amino acid is selected from one or more of lysine, glutamic acid, threonine and tryptophan.
  3. 3. The method according to claim 1, wherein the molar ratio of the silicon source, the aluminum source and water in step S2 is (0.02-1.32): 0.001-0.025): 4.5-45; preferably, the silicon source is selected from one or more of ethyl orthosilicate, silica sol and sodium silicate; Preferably, the aluminium source is selected from one or more of alumina, sodium aluminate, aluminium sol, pseudoboehmite.
  4. 4. The method of claim 1, wherein the molar ratio of the platinum salt, the silicon source, and the aluminum source in the initial gel is (0.001-0.012): 0.02-1.32): 0.001-0.025.
  5. 5. The method of claim 1, wherein the structure directing agent is a quaternary ammonium salt; Preferably, the quaternary ammonium salt is selected from one or more of tetrapropylammonium hydroxide, tetrabutylammonium hydroxide and tetrapropylammonium bromide; preferably, the mass ratio of the xerogel powder to the structure directing agent is (0.5-1.5): 0.5-3.0.
  6. 6. The preparation method according to claim 1, characterized in that the preparation method comprises the steps of: s1, dissolving 1.5-2.5g of chloroplatinic acid and 10-20g of lysine in 100ml of water to obtain a solution A; s2, dissolving 9-15g of silica sol and 0.5-1g of alumina in 120ml of water to obtain a solution B; S3, mixing the solution A and the solution B to form initial gel, and drying and grinding the initial gel to obtain xerogel powder; and S4, mixing the xerogel powder with a structure directing agent according to a mass ratio of 1:1, crystallizing, and washing, drying and roasting the obtained crystallized product to obtain the zeolite-based denitration catalyst.
  7. 7. The method according to claim 1, wherein the crystallization temperature is 110 to 180 ℃ and the crystallization time is 24 to 72 hours.
  8. 8. A zeolite-based denitration catalyst produced by the production method according to any one of claims 1 to 7.
  9. 9. The zeolite-based denitration catalyst of claim 8, wherein the catalyst is a pt@zsm-5 catalyst; preferably, the Pt content in the Pt@ZSM-5 catalyst is 0.05-1.0wt%; Preferably, the Pt@ZSM-5 molecular sieve in the Pt@ZSM-5 catalyst is in a shape of a coffin plate with the length multiplied by the width of 1 μm multiplied by 0.5 μm.
  10. 10. Use of the zeolite-based denitration catalyst as claimed in claim 8 or 9 in SCR flue gas denitration.

Description

Arsenic-resistant high-temperature-resistant zeolite-based denitration catalyst and preparation method thereof Technical Field The invention belongs to the technical field of catalysts and fine chemical engineering, and particularly relates to an arsenic-resistant and high-temperature-resistant zeolite-based denitration catalyst and a preparation method thereof. Background Nitrogen oxides are one of the main atmospheric pollutants and are the main cause of acid rain and photochemical smog. Coal-fired power plants are one of the most significant sources of NOx pollution. The main current technology of flue gas denitration is a Selective Catalytic Reduction (SCR) technology, and the core principle is that under the action of a specific catalyst, a reducing agent (usually ammonia gas or urea aqueous solution) is utilized to perform a chemical reaction with nitrogen oxides (mainly NO and NO 2, collectively called NO x) in flue gas in a 'selective' manner, rather than being oxidized by a large amount of oxygen in flue gas, so as to generate harmless nitrogen (N 2) and water (H 2 O), thereby greatly reducing the emission of NO x. With the increasing strictness of environmental protection laws, regulations and standards and the increasing of law enforcement, the SCR technology with mature technology, high denitration rate and no secondary pollution will gradually become the mainstream technology of the flue gas denitration market in China. The catalyst is an important component of the SCR system, and its performance directly affects the overall denitration effect of the SCR system. The production and preparation of the catalyst occupy more than 20% of the initial construction cost of the SCR system, so the service life of the catalyst determines the running cost of the SCR system. The fly ash of the coal-fired flue gas contains toxic elements such As heavy metal elements (As and Pb), alkali metal elements (K, na), alkaline earth metal elements (Ca and Mg) and the like, and can lead to poisoning and deactivation of the SCR denitration catalyst. Among various toxic elements, arsenic has a particularly obvious poisoning effect on the denitration catalyst. In the coal types used in coal-fired power plants in China, the proportion of high-arsenic coal (arsenic content is more than 80 mg/kg) accounts for about 10%. In addition, with the continuous increase of the coal and electricity cost and the promotion of co-firing, the components in the flue gas are more complex, the heavy metal content is increased, and the traditional VMo/Ti catalyst is easy to poison and inactivate. In addition, conventional VMo/Ti catalysts are prone to sintering agglomeration of the active components at high temperatures (> 420 ℃), which also exacerbates the degree of catalyst deactivation. Therefore, there is a need to develop a novel denitration catalyst having high arsenic resistance and high-temperature activity. In view of this, the present invention has been made. Disclosure of Invention The invention aims to provide a novel denitration catalyst with strong arsenic resistance and high-temperature activity, and a preparation method of the denitration catalyst. In one aspect, the application provides a method for preparing a zeolite-based denitration catalyst, which is characterized by comprising the following steps: s1, dissolving platinum salt and amino acid in water to obtain a solution A; s2, dissolving a silicon source and an aluminum source in water to obtain a solution B; S3, mixing the solution A and the solution B to form initial gel, and drying and grinding the initial gel to obtain xerogel powder; and S4, mixing the xerogel powder with a structure directing agent, crystallizing, and washing, drying and roasting the obtained crystallized product to obtain the zeolite-based denitration catalyst. In some embodiments of the invention, the molar ratio of the platinum salt to the amino acid in step S1 is from 0.01 to 0.9. Preferably, the molar ratio of the platinum salt to the amino acid is 0.01-0.1, more preferably 0.04-0.06. In some specific embodiments, the molar ratio of the platinum salt to the amino acid is 0.05. In some specific embodiments, the molar ratio of the platinum salt to the amino acid is 0.06. In some embodiments of the invention, the platinum salt is selected from one or more of chloroplatinic acid, sodium hexachloroplatinate, potassium hexachloroplatinate. In some embodiments of the invention, the amino acid is selected from one or more of lysine, glutamic acid, threonine, and tryptophan. In some embodiments of the invention, the molar ratio of the silicon source, the aluminum source, and water in step S2 is (0.02-1.32): (0.001-0.025): (4.5-45). Preferably, the molar ratio of the silicon source, the aluminum source and the water in the step S2 is (0.02-0.2): (0.002-0.02): (5-15), more preferably (0.05-0.08): (0.005-0.015): (5-10). In some specific embodiments, the molar ratio of the silicon source, the aluminum sou