Low-temperature sulfur-resistant denitration catalyst, preparation method and application thereof

Abstract

The application relates to a low-temperature sulfur-resistant denitration catalyst as well as a preparation method and application thereof, and belongs to the technical field of flue gas purification. The preparation method comprises the following steps: soaking NS-HPC in acid liquor to obtain modified NS-HPC; impregnating the modified NS-HPC in a molybdenum source solution; then, preparing a mixed solution of a cerium source, a manganese source and a cobalt source, and impregnating the material in the mixed solution; and then, calcining the impregnated material under a protective atmosphere at 250-300 DEG C for 2-4 hours, and then calcining the impregnated material under an oxidizing atmosphere at 350-450 DEG C for 10-20 minutes. The catalyst adopts acid liquor to introduce oxygen-containing acidic functional groups in the inner wall of micropores, then makes Mo species preferentially anchor in the defect sites and part of the mesopores of the carrier, then loads cerium, manganese and cobalt in the second impregnation, then makes the metal nitrate decompose into oxides, and then calcines at a higher temperature for a short time to form a stable composite oxide structure. After long-time operation under a high-sulfur atmosphere, the catalyst has extremely small activity attenuation.

Description

Technical Field

[0001] This invention belongs to the field of flue gas purification technology, specifically relating to a low-temperature anti-sulfurization and denitrification catalyst, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Selective catalytic reduction (NH3-SCR) of ammonia is an effective method for removing NOx from industrial flue gas. Placing the SCR reactor after a dust collector avoids physical wear and clogging of the catalyst's porous channels caused by fly ash from untreated flue gas, and also prevents heavy metal poisoning of catalyst active sites, extending catalyst life and reducing maintenance costs. However, it also lowers the flue gas temperature to 200°C or even lower. Most commercial catalysts, such as V2O4-WO3 / TiO2 catalysts, require operation at temperatures of 300–400°C. Therefore, developing denitrification catalysts with excellent low-temperature activity has become a hot topic in this field.

[0004] On the other hand, the high concentration of sulfur dioxide in the flue gas is easily adsorbed and oxidized by the catalyst into sulfur trioxide, which then reacts with NH3 and water to form sulfate. The decomposition temperature of sulfate is as high as 280°C, so it is easy to clog the pores during the low-temperature denitrification process, which will also lead to rapid deactivation of the catalyst.

[0005] Therefore, developing a novel catalyst that can not only efficiently denitrate at low temperatures but also actively cope with high-sulfur environments, inhibit the accumulation of ammonium bisulfate through an intrinsic mechanism and achieve self-regeneration, thereby ensuring long-term catalytic stability, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a low-temperature sulfur-resistant denitrification catalyst, its preparation method, and its application. This catalyst overcomes the defects of existing low-temperature denitrification catalysts, such as easy poisoning and deactivation in high-sulfur environments and difficulty in regeneration, through the synergistic effect of multiple components on a porous carbon surface. It achieves efficient and stable denitrification in the low-temperature range of 150-250℃ and has self-regeneration capability.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, a method for preparing a low-temperature anti-sulfurization and denitrification catalyst includes the following steps: S1. Immerse NS-HPC in acid solution to obtain modified NS-HPC; S2. The modified NS-HPC is impregnated in a molybdenum source solution with a concentration of 0.1~0.3 g / L to obtain the first impregnated material; S3. Prepare a mixed solution of cerium source, manganese source and cobalt source with an elemental molar ratio of 1:(2~4):(0.05~0.15), and immerse the first impregnation material in the mixed solution to obtain the second impregnation material; S4. The second impregnated material is calcined at 250~300℃ in a protective atmosphere for 2~4 hours, and then calcined at 350~450℃ in an oxidizing atmosphere for 10~20 minutes to obtain the low-temperature anti-sulfurization and denitrification catalyst.

[0008] Secondly, the low-temperature anti-sulfur denitrification catalyst prepared by the above-mentioned method is a low-temperature anti-sulfur denitrification catalyst.

[0009] Thirdly, the application of the aforementioned low-temperature anti-sulfurization and denitrification catalyst in flue gas denitrification.

[0010] The beneficial effects of this invention are as follows: 1. In the preparation method of the low-temperature anti-sulfur denitrification catalyst proposed in this invention, NS-HPC is subjected to mild oxidation treatment with acid solution, which preferentially introduces oxygen-containing acidic functional groups such as carboxyl groups and phenolic hydroxyl groups into the inner wall of micropores, thereby enhancing its adsorption capacity and selectivity for SO2. The nitrogen-containing functional group modification of NS-HPC itself can preferentially adsorb and restrict the inward diffusion of SO2, while sulfur doping enhances the acidity of the support surface, which is beneficial to the adsorption of NH3. Then, a first impregnation is performed to preferentially anchor Mo species in the defect sites and some mesopores of the support. Then, cerium, manganese and cobalt are loaded in the second impregnation. First, it is calcined in a protective atmosphere to fully decompose the metal nitrates into oxides and avoid excessive oxidation of carbon support. Then, it is calcined at a higher temperature for a short time to stabilize the crystal form of metal oxides and form a stable composite oxide structure.

[0011] 2. The low-temperature anti-sulfur denitrification catalyst provided by this invention employs an "active defense-directional transfer-in-situ decomposition" anti-sulfur mechanism. Nitrogen-sulfur dual-doped hierarchical porous carbon (NS-HPC) serves as the catalyst's main support and protective barrier, providing active defense. Its hierarchical channels (micropores-mesopores-macropores) provide optimized transport pathways for reactants and products. Micropores, modified with nitrogen-containing functional groups, preferentially adsorb and restrict SO2 diffusion inwards; mesopores and macropores provide the primary sites for loading active components and catalytic reactions. Sulfur doping further enhances the acidity of the support surface, facilitating NH3 adsorption. By introducing Mo oxides as "sulfur transfer agents," poisoned sulfur species are actively captured and transferred to dedicated decomposition sites, providing directional transfer functionality. The oxygen-rich defect sites on the carbon support surface are ammonium bisulfate decomposition sites; during carbon support preparation, a large number of defects and oxygen-containing functional groups are introduced through plasma treatment or strong acid etching. These sites can catalyze the in-situ decomposition of ABS or ammonium sulfate transferred by Mo, converting them into gaseous SO2, N2, and H2O and desorbing them, thereby achieving self-cleaning and regeneration of the catalyst and providing in-situ decomposition function. This anti-sulfur mechanism fundamentally solves the sulfur poisoning problem. The synergistic effect of the Ce-Mn-Co ternary active system, combined with the large specific surface area of ​​the carbon support, allows the catalyst to ignite at 150℃ and maintain a NOx conversion rate of over 90% within the 150-300℃ range. Even after long-term operation in high-sulfur atmospheres (such as 300 ppm SO2), the catalyst activity decays very little. Thanks to its inherent self-regeneration mechanism, even if a small amount of ammonium sulfate precursor forms, it can be rapidly transferred and decomposed, ensuring a long catalyst lifespan.

[0012] 3. The preparation process of this invention is green and controllable: the preparation process avoids the use of a large amount of solvent, and some steps can be carried out using a solvent-free method; the combination of stepwise impregnation and ultrasonic treatment achieves precise and uniform loading of multiple components in complex porous structures. Attached Figure Description

[0013] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0014] Figure 1 The figure shows the performance characterization results of NH3-SCR in Example 1. Detailed Implementation

[0015] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0016] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0017] One or more embodiments of the present invention provide a method for preparing a low-temperature anti-sulfurization and denitrification catalyst, comprising the following steps: S1. Immerse NS-HPC in acid solution to obtain modified NS-HPC; S2. The modified NS-HPC is impregnated in a molybdenum source solution with a concentration of 0.1~0.3 g / L to obtain the first impregnated material; S3. Prepare a mixed solution of cerium source, manganese source and cobalt source with an elemental molar ratio of 1:(2~4):(0.05~0.15), and immerse the first impregnation material in the mixed solution to obtain the second impregnation material; S4. The second impregnated material is calcined at 250~300℃ in a protective atmosphere for 2~4 hours, and then calcined at 350~450℃ in an oxidizing atmosphere for 10~20 minutes to obtain the low-temperature anti-sulfurization and denitrification catalyst.

[0018] In the above steps, NS-HPC is first subjected to mild oxidation treatment with acid to introduce oxygen-containing acidic functional groups such as carboxyl and phenolic hydroxyl groups into the inner wall of the micropores, thereby enhancing its adsorption capacity and selectivity for SO2. Then, in the first impregnation process, Mo species are preferentially anchored in the defect sites and some mesopores of the support. In the second impregnation process, cerium, manganese and cobalt are loaded. Furthermore, the carbon support is calcined in a protective atmosphere to fully decompose the metal nitrates into oxides while avoiding excessive oxidation of the carbon support. Finally, the carbon support is calcined at a higher temperature for a short time to form a stable composite oxide structure.

[0019] Optionally, in S1, the preparation method of the NS-HPC includes: mixing HPC and thiourea at a mass ratio of (2~3):1, and then treating it at 700~800℃ for 2~3h under a protective atmosphere; using thiourea as both a nitrogen source and a sulfur source, and achieving simultaneous doping of nitrogen and sulfur elements at high temperature.

[0020] Optionally, in S1, the acid solution is dilute nitric acid or a mixed acid; the concentration of the dilute nitric acid is 3~6M, and the mixed acid is obtained by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of (1~3):1; in the mixed raw materials of the mixed acid, the concentration of concentrated nitric acid is 68wt%; and the concentration of concentrated sulfuric acid is 98wt%.

[0021] Optionally, in S1, NS-HPC is immersed in acid solution and refluxed at 60~70℃ for 4~5 hours, then washed and dried; during the process, the micropores are modified with acidic functional groups to enhance their adsorption capacity and selectivity for SO2; the acidic functional groups interact specifically with the lone pair electrons or basic sites of SO2 to form strong chemical bonds, which greatly improves the adsorption capacity; SO2 interacts more strongly with acidic sites than with gases such as CO2 and N2, thus being preferentially adsorbed in the mixed gas.

[0022] Optionally, in S2, the molybdenum source is ammonium molybdate, which is impregnated using an equal-volume method. After ultrasonic treatment for 30-40 minutes, it is left to stand for 12-14 hours and then dried. The equal-volume impregnation method can use an impregnation liquid with a volume exactly equal to the total pore volume of the carrier to impregnate the carrier, so as to fully load the catalytic components in the liquid raw material onto the carrier. Ultrasonic treatment ensures that the active components are uniformly dispersed inside the carbon carrier with high specific surface area and rich pores.

[0023] Optionally, in S3, the cerium source includes one or more of cerium nitrate and cerium ammonium nitrate, the manganese source includes one or more of manganese nitrate, manganese acetate and potassium permanganate, and the cobalt source includes one or more of cobalt nitrate and cobalt acetate.

[0024] Optionally, in step S3, the impregnation method includes: using an equal-volume impregnation method, ultrasonic treatment for 30-40 minutes, standing for 12-14 hours, drying, and performing a second ultrasonic-assisted impregnation with the above-mentioned Mo-loaded carrier; the impregnation process in step S2 causes molybdenum to be preferentially anchored in the defect sites and some pores of the carrier; the impregnation process in step S3 is used for active ingredients such as Ce-Mn-Co.

[0025] Optionally, in S4, the protective atmosphere includes a helium atmosphere. Calcination in a protective atmosphere can decompose the oxygen-containing metal salt into oxides while avoiding excessive oxidation of the carbon support. The oxidizing atmosphere is a low-oxygen-content oxidizing atmosphere with an oxygen content of 0.1~1.0 vol%, including a mixture of oxygen and nitrogen. Calcination in this atmosphere can consolidate the composite oxide structure, prevent the catalyst from deactivating due to phase transformation or sintering during subsequent use, and improve durability. If the oxygen content in the oxidizing atmosphere is too high, it will cause significant oxidation or even ablation of the carbon support, resulting in catalyst structure collapse and a significant decrease in specific surface area. At the same time, the active metal oxide may undergo uncontrollable grain growth or phase transformation due to excessive oxidation, which will accelerate catalyst sintering and deactivation.

[0026] One or more embodiments of the present invention provide a low-temperature anti-sulfur denitrification catalyst prepared by the above-mentioned method.

[0027] The catalyst uses nitrogen-sulfur dual-doped hierarchical porous activated carbon (NS-HPC) as a support, cerium-manganese-cobalt (Ce-Mn-Co) composite oxide as the main active component, and introduces molybdenum (Mo) oxide as a key sulfur transfer agent and promoter.

[0028] Nitrogen-sulfur dual-doped hierarchical porous carbon (NS-HPC) serves as both the catalyst support and protective barrier. Its hierarchical pore structure (micropores-mesopores-macropores) provides optimized transport pathways for reactants and products. Micropores, through acid treatment, introduce oxygen-containing acidic functional groups, enhancing their adsorption capacity and selectivity for SO2. Furthermore, nitrogen-containing functional group modification (including amino and amide groups) preferentially adsorbs and restricts SO2 diffusion into the micropores. Mesopores and macropores provide the primary sites for loading active components and catalytic reactions. Sulfur doping further enhances the acidity of the support surface, facilitating NH3 adsorption. The oxygen-rich defect sites on the carbon support surface serve as ammonium bisulfate decomposition sites. During carbon support preparation, numerous defects and oxygen-containing functional groups are introduced through plasma treatment or strong acid etching. These sites can catalytically decompose ABS or ammonium sulfate transferred from Mo in situ, converting it into gaseous SO2, N2, and H2O, which are then desorbed, thus achieving catalyst self-cleaning and regeneration.

[0029] Cerium-manganese-cobalt (Ce-Mn-Co) composite oxides are active centers for low-temperature denitrification, and there is a Ce-Mn bond between Ce and Mn. 4+ +Mn 3+ Mn 4+ +Ce 3+ The redox cycle greatly enhances the oxygen storage capacity and low-temperature activity of the catalyst; Co doping further enhances the Lewis acid sites on the catalyst surface, promotes the adsorption and activation of NOx, and broadens the high-activity temperature window.

[0030] Molybdenum (Mo) oxides act as promoters of sulfur transfer and in-situ decomposition. They can selectively bind with SO3 or trace amounts of ABS generated during the reaction to form unstable molybdenum-sulfur intermediates, thereby preventing SO3 and NH3 from directly forming ABS and depositing on Ce-Mn-Co active sites. Subsequently, these intermediates guide sulfur species to specific oxygen-rich defect sites on the carbon support.

[0031] One or more embodiments of the present invention provide the application of the above-mentioned low-temperature anti-sulfur denitrification catalyst in flue gas denitrification.

[0032] Optionally, the flue gas includes SO2 with a concentration of 500~1500 mg / m³. 3 The smoke.

[0033] The present invention will be further described below with reference to specific embodiments.

[0034] Example 1 In existing technologies, manganese-based (MnOx) and cerium-based (CeOx) catalysts have been extensively studied due to their excellent low-temperature reduction performance. For example, Co-doped Ce / MnOx composites can achieve approximately 90% NOx conversion within a wide temperature window of 100-275 °C using a solvent-free synthesis method. However, such catalysts still face significant challenges in flue gas containing high concentrations of SO2. The main methods to improve the sulfur resistance of catalysts include: (1) Physical mixing of adsorbents: such as physically mixing vanadium tungsten titanium catalyst (V / W / Ti) with HY zeolite, using zeolite to preferentially adsorb SO2; however, this method is a physical isolation, which does not fundamentally solve the problem of the generation and accumulation of ammonium bisulfate, and may affect the overall activity and mechanical strength of the catalyst; (2) Surface acid modification: enhancing the acidity of the support surface through nitrogen doping or plasma treatment, such as plasma-engineered activated carbon fibers (ACFs) exhibiting high sulfate selectivity when catalyzing the oxidation of H2S at room temperature, but the effect of this strategy in complex low-temperature denitrification reaction environments needs to be verified; (3) Synergistic effect of multi-metal oxides: multi-metal oxide catalysts supported on Fe2O3, MnO2, CoO2, CeO2 and V2O5 have good desulfurization and denitrification performance; however, their sulfur resistance mechanism is still limited to the intrinsic resistance of the active components and lacks the ability to actively remove deposited ammonium sulfate.

[0035] This embodiment provides a low-temperature sulfur-resistant denitrification catalyst, the preparation method of which includes: S0. Using biomass (such as straw, coconut shell) or resin as a precursor, carbonization is carried out at 500℃ for 2 hours, followed by activation with KOH to prepare a porous carbon material with a three-dimensional interconnected hierarchical pore structure, namely HPC. 2g of the prepared hierarchical porous carbon (HPC) is placed in a beaker, 1g of thiourea is added, and the mixture is thoroughly mixed before being transferred to a tube furnace. Under an Ar gas flow, the furnace temperature is raised to 700℃ and maintained at that temperature for 2 hours. After natural cooling, nitrogen-sulfur dual-doped hierarchical porous carbon (NS-HPC) is obtained.

[0036] S1. Add 1g of NS-HPC to 50mL of 3M dilute nitric acid solution and stir and reflux at 60℃ for 4h; after cooling, filter, wash with deionized water until neutral, and dry at 110℃ for 12h to obtain NS-HPC with acid-modified micropores, i.e., modified NS-HPC.

[0037] S2. Prepare an aqueous solution of ammonium molybdate with a concentration of 0.1 g / L. Take 4 mL of the ammonium molybdate aqueous solution and mix it with 1 g of modified NS-HPC. After ultrasonic treatment for 30 min, let it stand at room temperature for 12 h, and then dry it at 110 °C to obtain the first impregnated material.

[0038] S3. Weigh 1g of cerium nitrate, 1.74g of manganese nitrate and 0.07g of cobalt nitrate according to the molar ratio of Ce, Mn and Co of 1:3:0.1, and add 50ml of distilled water to prepare a mixed metal salt solution; take 4ml of the mixed metal salt solution and mix it with the first impregnation material by the equal volume impregnation method; after ultrasonic treatment for 30min, let it stand at room temperature for 12h, and then dry it at 110℃ for 12h to obtain the second impregnation material.

[0039] S4. The second impregnating material is first placed in a muffle furnace under a helium atmosphere and heated to 300℃ at a heating rate of 2℃ / min, and calcined for 3h. Then the atmosphere is switched to a mixture of oxygen and nitrogen with an oxygen content of 0.5 vol%, and the temperature is raised to 400℃ and calcined for another 15min. After natural cooling, the target catalyst is obtained, denoted as Ce-Mn-Co-Mo / NS-HPC. The actual loadings of each element are calculated to be Ce: 25.8mg, Mn: 30.3mg, Ce: 1.09mg, and Mo: 0.21mg.

[0040] The catalyst obtained in Example 1 was pressed into tablets, sieved to 40-60 mesh, and its NH3-SCR performance was evaluated in a fixed-bed reactor. The composition of the catalyst gas was: 200 ppm NO, 200 ppm NH3, 5% O2, with N2 as the equilibrium gas, a total gas flow rate of 500 mL / min, and a space velocity of 15000 h⁻¹. -1 During the process, at a reaction temperature of 200℃, 300 ppm SO2 (equivalent to a concentration of 865 mg / m³) was introduced into the reaction gas. 3 Experiments were conducted at different temperatures, and the results are shown in the attached figure. Figure 1 As shown.

[0041] Comparative Example 1 A Ce-Mn-Co / HPC catalyst differs from Example 1 in that it does not undergo nitrogen and sulfur doping, does not modify the micropores with acid, and does not load Mo components. Instead, it directly employs step S3, immersing HPC in a mixed metal salt solution and then processing it according to the method of Example 1 to obtain a catalyst in which Ce-Mn-Co active components are loaded onto unmodified hierarchical porous carbon. The actual loading amounts of each element were calculated to be Ce: 25.8 mg, Mn: 30.3 mg, and Ce: 1.09 mg.

[0042] Example 2 A catalyst, which differs from Example 1 in that: in S3, the molar ratio of Ce, Mn and Co is changed to 1:3:0.05, while all other aspects are the same as in Example 1; the actual loading amounts of each element are calculated to be Ce: 25.8 mg, Mn: 30.3 mg, Ce: 0.55 mg, and Mo: 0.21 mg.

[0043] Example 3 A catalyst, which differs from Example 1 in that: in S2, the concentration of the aqueous solution containing ammonium molybdate is changed to 0.2 g / L, while all other aspects are the same as in Example 1; the actual loading amounts of each element are calculated to be Ce: 25.8 mg, Mn: 30.3 mg, Ce: 0.55 mg, and Mo: 0.42 mg.

[0044] Example 4 A catalyst, differing from Example 1, is as follows: In S1, 68wt% nitric acid and 98wt% sulfuric acid are mixed in a 1:1 volume ratio to obtain a mixed acid. Then, 1g of NS-HPC is added to 50mL of the mixed acid, and the mixture is stirred and refluxed at 60°C for 4h. After cooling, the mixture is filtered, washed with deionized water until neutral, and dried at 110°C for 12h to obtain NS-HPC with acid-modified micropores, i.e., modified NS-HPC.

[0045] The other raw materials and preparation methods are the same as in Example 1.

[0046] The catalysts obtained from each example and comparative example were pressed into tablets, sieved to 40-60 mesh, and their NH3-SCR performance was evaluated in a fixed-bed reactor. The composition of the catalyst gas was: 200 ppm NO, 200 ppm NH3, 5% O2, with N2 as the equilibrium gas, a total gas flow rate of 500 mL / min, and a space velocity of 15000 h⁻¹. -1 During the process, at a reaction temperature of 200℃, 300ppm SO2 was introduced into the reaction gas (added during sulfur resistance testing, resulting in a calculated concentration of 865mg / m³). 3 It will continue to run for 10 hours.

[0047] In the first stage before the introduction of SO2, the NOx conversion rate of the catalyst in Example 1 reached 92.3% at 175°C and maintained a conversion rate close to 100% in the range of 200-270°C. In the second stage after the introduction of SO2, the NOx conversion rate slowly decreased from the initial 99.4% to 95.8% in 10 hours, showing excellent stability.

[0048] The catalyst in Comparative Example 1 had a conversion rate of 86.7% at 200°C in the first stage, with a maximum conversion rate of 92.5%. After the introduction of SO2 in the second stage, the conversion rate dropped rapidly from 86.7% to below 60%, indicating severe sulfur poisoning.

[0049] After SO2 was introduced in the second stage, the NOx conversion rate of the catalyst in Example 2 slowly decreased from the initial 98.7% to 95.2%, and the catalyst also exhibited excellent low-temperature activity and sulfur resistance.

[0050] After SO2 was introduced in the second stage, the NOx conversion rate of the catalyst in Example 3 slowly decreased from the initial 99.4% to 96.5%, and the catalyst also exhibited excellent low-temperature activity and sulfur resistance.

[0051] After SO2 was introduced in the second stage, the NOx conversion rate of the catalyst in Example 4 slowly decreased from the initial 99.5% to 95.5%, and the catalyst also exhibited excellent low-temperature activity and sulfur resistance.

[0052] When the Ce:Mn:Co molar ratio is in the range of 1:(2-4):(0.05-0.15) and the ammonium molybdate concentration is 0.1~0.3 g / L, the catalyst can maintain both excellent low-temperature activity and sulfur resistance. The corresponding element loadings are Ce: 25.8 mg, Mn: 20.1~40.4 mg, Ce: 0.55~1.65 mg, and Mo: 0.21~0.63 mg.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a low-temperature anti-sulfurization and denitrification catalyst, characterized in that, Includes the following steps: S1. Immerse NS-HPC in acid solution to obtain modified NS-HPC; S2. The modified NS-HPC is impregnated in a molybdenum source solution with a concentration of 0.1~0.3 g / L to obtain the first impregnated material; S3. Prepare a mixed solution of cerium source, manganese source and cobalt source with an elemental molar ratio of 1:(2~4):(0.05~0.15), and immerse the first impregnation material in the mixed solution to obtain the second impregnation material; S4. The second impregnated material is calcined at 250~300℃ in a protective atmosphere for 2~4 hours, and then calcined at 350~450℃ in an oxidizing atmosphere for 10~20 minutes to obtain the low-temperature anti-sulfurization and denitrification catalyst.

2. The preparation method of the low-temperature anti-sulfurization and denitrification catalyst as described in claim 1, characterized in that, In S1, the preparation method of NS-HPC includes: mixing HPC and thiourea at a mass ratio of (2~3):1, and then treating the mixture at 700~800℃ for 2~3 hours under a protective atmosphere.

3. The preparation method of the low-temperature anti-sulfurization and denitrification catalyst as described in claim 1, characterized in that, In S1, the acid solution is dilute nitric acid or a mixed acid, the concentration of the dilute nitric acid is 3~6M, and the mixed acid is obtained by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of (1~3):

1.

4. The preparation method of the low-temperature anti-sulfurization and denitrification catalyst as described in claim 1, characterized in that, In S1, NS-HPC is immersed in acid solution and refluxed at 60~70℃ for 4~5 hours, then washed and dried.

5. The preparation method of the low-temperature anti-sulfurization and denitrification catalyst as described in claim 1, characterized in that, In S2, the molybdenum source is ammonium molybdate, which is impregnated by equal volume, ultrasonically treated for 30-40 minutes, left to stand for 12-14 hours, and then dried.

6. The preparation method of the low-temperature anti-sulfurization and denitrification catalyst as described in claim 1, characterized in that, In S3, the cerium source includes one or more of cerium nitrate and cerium ammonium nitrate, the manganese source includes one or more of manganese nitrate, manganese acetate and potassium permanganate, and the cobalt source includes one or more of cobalt nitrate and cobalt acetate.

7. The preparation method of the low-temperature anti-sulfurization and denitrification catalyst according to claim 1, characterized in that, In S3, the impregnation method includes: using the equal volume impregnation method, ultrasonic treatment for 30-40 minutes, standing for 12-14 hours, and drying.

8. The preparation method of the low-temperature anti-sulfurization and denitrification catalyst as described in claim 1, characterized in that, In S4, the protective atmosphere includes a helium atmosphere, and the oxidizing atmosphere is a low oxygen content oxidizing atmosphere with an oxygen content of 0.1~1.0 vol%.

9. A low-temperature anti-sulfur denitrification catalyst prepared by the method described in claim 1.

10. The application of the low-temperature anti-sulfur denitrification catalyst as described in claim 9 in flue gas denitrification, characterized in that, The flue gas contains SO2 with a concentration of 500~1500 mg / m³. 3 The smoke.

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