A rare earth-doped manganese-based low-temperature denitration catalyst and its preparation method

Abstract

This invention belongs to the field of environmental catalytic materials technology, and relates to a rare earth-doped manganese-based low-temperature denitrification catalyst and its preparation method. The preparation steps of this invention are as follows: S1, stacking corrugated plates and flat plates to form functional units; S2, taking a specific amount of deionized water, then sequentially adding a dispersant, TiO2 powder, and a binder, and stirring several times to obtain a TiO2 suspension; S3, sequentially adding soluble manganese salt and soluble salts of rare earth elements to the TiO2 suspension, stirring to obtain an impregnation solution; and loading the impregnation solution onto the surface of the functional unit to obtain a modified functional unit, which is then sequentially dried and calcined to obtain the denitrification catalyst. This invention is particularly suitable for denitrification scenarios of medium- and low-temperature flue gas (150~300℃), solving the technical pain points of insufficient low-temperature activity and poor adaptability of traditional catalysts.

Description

Technical Field

[0001] This invention belongs to the field of environmental catalytic materials technology, and relates to a rare earth-doped manganese-based low-temperature denitration catalyst and its preparation method. Background Technology

[0002] Currently, the most widely used commercially available selective catalytic reduction (SCR) catalysts for industrial denitrification are titanium-based vanadium catalysts (V₂O₅-WO₃ / TiO₂). The core advantage of this type of denitrification catalyst lies in its stable catalytic performance at high temperatures; its optimal activity temperature window is 300℃~420℃, within which it effectively inhibits the catalytic activity of nitrogen oxides (NO₃). x The denitrification efficiency of this catalyst can reach over 85%, meeting the stringent requirements for high-temperature flue gas denitrification in coal-fired power plants. However, titanium-based vanadium catalysts (V2O5-WO3 / TiO2) have significant low-temperature adaptability defects—when the flue gas temperature is low (especially <300℃), the redox performance of the active component V2O5 is difficult to fully exert, and the reactants ammonia (NH3) and NO... x The adsorption, activation, and reaction kinetics processes on the catalyst surface are hindered, resulting in a significant decrease in denitrification efficiency (the denitrification rate is usually below 60%), which fails to meet current environmental emission standards. At the same time, this type of denitrification catalyst is susceptible to poisoning and deactivation by SO2 and H2O in flue gas, which ultimately leads to a shortened service life of the denitrification catalyst.

[0003] Furthermore, there are application barriers for titanium-based vanadium catalysts in denitrification scenarios outside the power industry. Currently, the flue gas emission temperature in non-power industries such as coking, cement, and glass kilns is generally below 300℃, far below the optimal activity temperature window of existing titanium-based vanadium catalysts.

[0004] While existing technologies include research on low-temperature SCR denitrification catalysts, several technical bottlenecks remain to be addressed: firstly, poor activity stability leads to a decline in denitrification efficiency during long-term continuous operation; secondly, insufficient resistance to sulfur and water means that catalyst poisoning and deactivation problems are not fundamentally resolved, hindering long-term stable operation; and thirdly, complex molding processes fail to meet the engineering application requirements of industrial denitrification. Therefore, there is an urgent need to invent a denitrification catalyst to overcome these limitations. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and propose a rare earth-doped manganese-based low-temperature denitration catalyst and its preparation method. This invention aims to provide a manganese-based low-temperature SCR denitration catalyst with high denitration efficiency (≥90%) and good water and sulfur resistance in the low-temperature range of 150℃~300℃, which is also easy to industrially produce.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention discloses a rare earth-doped manganese-based low-temperature denitration catalyst, wherein the denitration catalyst comprises a functional unit formed by alternating stacking of corrugated plates and flat plates, and the functional unit is loaded with a manganese-based active component supported by TiO2 powder.

[0007] Specifically, both the corrugated plate and the flat plate are made of glass fiber as the base material.

[0008] Specifically, the geometric specific surface area of ​​the functional unit ranges from 400 to 1700 m². 2 / m 3 The porosity ranges from 60% to 85% to ensure its dispersibility as a carrier and the stability of active sites.

[0009] Specifically, the TiO2 powder is industrial grade or chemically pure, with a purity ≥99.0%, preferably anatase type.

[0010] Specifically, the binder is an inorganic binder, including but not limited to silica sol, aluminum sol, and aluminum dihydrogen phosphate, with silica sol being preferred; the solid content of the silica sol is 20% to 40%, preferably 30%.

[0011] Furthermore, the main component of the manganese-based active ingredient is manganese oxide, and the manganese oxide is doped with a specific type of rare earth active ingredient.

[0012] Specifically, the rare earth elements in the rare earth active components include one or more of cerium (Ce), thulium (Tm), yttrium (Y), lanthanum (La), praseodymium (Pr), neodymium (Nd), and samarium (Sm).

[0013] Furthermore, the precursor of the manganese oxide is a soluble manganese salt.

[0014] Specifically, the soluble manganese salt includes, but is not limited to, manganese acetate tetrahydrate, manganese nitrate, or manganese sulfate, preferably manganese acetate tetrahydrate (Mn(CH3COO)2•4H2O) or manganese nitrate (Mn(NO3)2•6H2O).

[0015] Specifically, the soluble manganese salt is analytically pure or chemically pure, with a purity ≥ 98.0%.

[0016] Furthermore, the precursor of the rare earth active component is a soluble salt of the corresponding rare earth element.

[0017] Specifically, the soluble salts of the corresponding rare earth elements are analytically pure or chemically pure, with a purity ≥ 98.0%.

[0018] Specifically, the soluble salts of the corresponding rare earth elements include, but are not limited to, nitrates, chlorides, or sulfates of the rare earth elements.

[0019] Secondly, this invention discloses a method for preparing a rare earth-doped manganese-based low-temperature denitration catalyst, comprising the following steps: S1. Glass fiber mat is selected as the skeleton material. After being made into a corrugated plate by molding liquid and molding process, it is then stacked with flat plate to form a functional unit. S2. Take a specific amount of deionized water, then add a specific amount of dispersant to it, and stir for the first time until completely dissolved to obtain a first solution; add a specific amount of TiO2 powder to the first solution and stir for the second time to obtain a second solution; then add a specific amount of binder to the second solution and stir for the third time until the binder and the second solution are fused to obtain a TiO2 suspension. S3. Take a specific amount of soluble manganese salt and a specific amount of soluble salt of rare earth elements, and add them sequentially to the TiO2 suspension. After stirring for the fourth time, an impregnation solution is obtained. The impregnation solution is loaded onto the surface of the functional unit using a single impregnation method to obtain a modified functional unit. The modified functional unit is then dried and calcined sequentially to obtain the denitrification catalyst.

[0020] Specifically, in S1, the preparation process and procedure of the structured carrier are existing mature technologies, and will not be described in detail in this specification; Specifically, the corrugated plate has a corrugation height of 3 mm to 10 mm and a corrugation pitch of 5 mm to 20 mm. Specifically, the dimensions (length × width × height) of the functional unit are preferably 200×150×150mm to 1000×500×300mm; Specifically, in S2, the dispersant includes, but is not limited to, polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP). The purpose of adding the dispersant is twofold: first, to inhibit the agglomeration of TiO2 powder particles during the dissolution process; and second, to improve the fluidity of the impregnation solution and ensure the consistency of the coating thickness. Specifically, in S2, the stirring methods for the first to third stirring are including but not limited to electromagnetic stirring and paddle stirring.

[0021] More specifically, in S2, the stirring speed for the first stirring, the second stirring, and the third stirring is 300~800 rpm, and the stirring time is 30~60 min.

[0022] Specifically, in S3, the fourth stirring method is preferably mechanical stirring, which includes, but is not limited to, electromagnetic stirring and paddle stirring. During the fourth stirring, ultrasonic dispersion is performed simultaneously to break up the agglomeration of the components in the impregnation solution.

[0023] More specifically, the stirring speed for the fourth stirring is 400-600 rpm, and the stirring time is 40-60 min.

[0024] More specifically, the first to fourth stirrings are all to avoid the phenomenon of excessively high local concentrations in the impregnation solution system, thereby preventing uneven distribution of manganese-based active ingredients with TiO2 as the carrier.

[0025] Specifically, in S3, the single-stage impregnation method is chosen instead of the coating method in order to ensure the consistency of the coating thickness on the catalyst surface, so that the manganese-based active components with TiO2 as the support are evenly distributed on the catalyst support.

[0026] More specifically, the catalyst surface coating formed by the one-time impregnation method has a thickness of tens to hundreds of micrometers; this process is to ensure that the coating does not crack or peel off, provided that there is a sufficient amount of manganese-based active ingredients on TiO2 as the carrier.

[0027] More specifically, the single-stage immersion method is preferably full immersion; the full immersion process can ensure the consistency of the coating thickness of the immersion liquid.

[0028] Specifically, in S3, the drying process is carried out simultaneously with heating and stirring (fifth stirring). The heating temperature is preferably 90°C. The purpose is to remove the moisture in the impregnation coating, so that the manganese-based active component with TiO2 as the carrier can be deposited in situ on the surface or pores of the catalyst carrier.

[0029] More specifically, the fifth stirring is preferably performed using a heat-collecting constant-temperature magnetic stirrer, with a stirring speed of 200-500 rpm and a stirring time of 2-4 hours, until the moisture in the catalyst surface coating evaporates and the binder is initially cured.

[0030] More specifically, stirring during the heating process (the fifth stirring) can prevent the manganese-based active components supported by TiO2 from migrating or agglomerating during the drying process, thereby ensuring the uniformity of catalyst loading.

[0031] More specifically, the uniformity standard for the loading of the denitrification catalyst is: the metal elements in the manganese-based active component supported by TiO2 are uniformly distributed on the catalyst support.

[0032] More specifically, the fifth stirring is to prevent the manganese-based active components supported by TiO2 from depositing on the catalyst support during the drying process, which would result in uneven distribution of the various metal elements on the catalyst support.

[0033] More specifically, in the laboratory, the uniformity of the denitrification catalyst loading can be directly observed using a surface scan mode combining SEM and EDS to determine whether the elemental distribution is uniform. In industrial production, the compressive strength, activity repeatability, and color consistency of the present invention can be indirectly judged by sampling and testing. If there are individual denitrification catalyst units with obviously uneven coatings (such as mottled color or local powder exposure), they are regarded as unqualified products and can be reworked or scrapped.

[0034] Furthermore, in S2, the molar ratio of deionized water: dispersant: TiO2 powder is in the range of (800~1200):(0.5~2):1; the mass of the binder is 5%~15% of the mass of TiO2 powder.

[0035] Furthermore, in S3, the molar ratio of rare earth metal ions in the soluble salt of the rare earth element to manganese ions in the soluble manganese salt is in the range of (0.1~0.5):1.

[0036] Furthermore, in S3, the molar ratio of the sum of the molar numbers of rare earth metal ions and manganese ions to Ti ions is in the range of (0.3~0.5):1.

[0037] Specifically, the core of this invention lies in the ratio of the manganese-based active ingredient to the TiO2 carrier.

[0038] More specifically, in the denitrification catalyst, the molar ratio of Mn ions to Ti ions is preferably 0.3:1, and the molar ratio of rare earth metal ions to Ti ions is preferably 0.075:1, 0.1:1, or 0.125:1.

[0039] More specifically, the preferred formulation described in the beneficial effects section of this specification is as follows: when the molar ratio of Mn ions to Ti ions in the denitrification catalyst is 0.3:1 and the molar ratio of rare earth metal ions to Ti ions is 0.1:1, the denitrification performance is optimal.

[0040] Furthermore, in S3, the drying process adopts a method of simultaneous heating and drying with stirring; the drying temperature is 80~150℃, the stirring speed is 200~500 rpm, and the stirring time is 2~4h; the calcination process has a calcination temperature range of 350℃~500℃ and a calcination time of 2~4h.

[0041] Compared with the prior art, the present invention has the following beneficial effects: First, the core of this invention lies in two key molar ratios: one is the molar ratio of manganese ions to rare earth metal ions within the manganese-based active component; the other is the ratio of the manganese-based active component to the TiO2 support – the molar ratio of the total amount of manganese ions and rare earth metal ions to the TiO2 support. The first key molar ratio determines the synergistic efficiency within the manganese-based active component, while the second key molar ratio controls the loading density of the active component on the support surface. Together, they ensure the overall performance of the catalyst.

[0042] Secondly, by introducing rare earth metal elements into the denitrification catalyst and precisely controlling the values ​​of the two key molar ratios, the present invention enables the denitrification catalyst to possess the following excellent characteristics: Firstly, in the medium-low temperature flue gas range of 150℃ to 300℃, the denitrification catalyst exhibits excellent resistance to NO. x The conversion rate remains consistently above 88%, making it suitable for low-temperature flue gas denitrification needs in non-power industries such as coking, cement, and glass kilns. Some optimized formulations achieve denitrification efficiencies exceeding 95% within the 200℃~300℃ temperature range. Compared to traditional titanium-based vanadium catalysts (denitrification rate below 60% below 300℃), this invention represents a qualitative breakthrough in low-temperature activity, meeting current stringent environmental standards. Secondly, this invention maintains high denitrification efficiency even under flue gas conditions containing SO2 and H2O (the denitrification rate remains consistently above 88% under continuous sulfur and water supply conditions), effectively addressing the technical challenges of sulfur poisoning and water inhibition in traditional low-temperature denitrification catalysts. Its denitrification stability is significantly superior to existing technologies. III. The denitrification catalyst uses glass fiber as a carrier and is cured and molded using an inorganic binder, solving the problems of high molding difficulty and low mechanical strength of traditional powder catalysts. Furthermore, the present invention features a corrugated structure, which increases the specific surface area while possessing excellent mechanical properties, and has a chemical life greater than 24,000 hours, meeting the requirements of long-term industrial operation and facilitating industrial production and application. V. This invention is not only applicable to medium- and low-temperature flue gas denitrification scenarios in non-power industries such as coking, cement, glass, and steel, but also compatible with low-load peak-shaving conditions of coal-fired power units in the power industry. It has strong environmental adaptability, filling the industrialization gap of domestic medium- and low-temperature SCR denitrification technology and providing solutions for ultra-low emission retrofitting in multiple industries in China. Attached Figure Description

[0043] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0046] Exemplary embodiments will now be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0047] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0048] Example 1 This embodiment provides a method for preparing a rare earth-doped manganese-based low-temperature denitration catalyst, including the following steps: S1. Fiberglass mat is selected as the skeleton material. It is manufactured into a corrugated board using a molding liquid and molding process, and then stacked with a flat plate to form a 500×300×300mm sheet with a geometric specific surface area of ​​1200 m². 2 / m 3 Functional unit with a porosity of 75%.

[0049] Specifically, the corrugated plate has a corrugation height of 10mm and a corrugation pitch of 15mm.

[0050] S2. Prepare 1200 mol of deionized water (equivalent to 21.6 L at room temperature and pressure), then add 0.5 mol of PEG-400 dispersant (equivalent to 200 g), and stir with a magnetic stirrer until completely dissolved to obtain a first solution; add 1 mol of TiO2 powder (equivalent to 80 g) to the first solution, and stir with a magnetic stirrer a second time to obtain a second solution; then add 5 g of silica sol with a solid content of 30% to the second solution, and stir a third time until the silica sol and the second solution are fused to obtain a TiO2 suspension; Specifically, the stirring speed for the first, second, and third stirring is 300 rpm, and the stirring time is 30 min for each. Specifically, the TiO2 powder is anatase type with a purity of 99.5%.

[0051] S3. Prepare 0.3 mol of manganese acetate tetrahydrate (Mn(CH3COO)2·4H2O) (corresponding to a mass of 74 g) and 0.1 mol of thulium nitrate hexahydrate Tm(NO3)3•6H2O (corresponding to a mass of 46.3 g), and add them sequentially to the TiO2 suspension. Then, perform a fourth stirring using a combination of ultrasonic and magnetic stirring to obtain an impregnation solution. Next, use a single impregnation method to load the impregnation solution onto the surface of the functional unit to obtain a modified functional unit. Place the modified functional unit in a heat-collecting constant-temperature magnetic stirrer and simultaneously perform a fifth stirring and heating drying. Then, place the dried modified functional unit in a muffle furnace for calcination to obtain the denitrification catalyst.

[0052] Specifically, the manganese acetate tetrahydrate (Mn(CH3COO)2•4H2O) and thulium nitrate hexahydrate (Tm(NO3)3•6H2O) are chemically pure with a purity of 99%. Specifically, the fourth stirring speed is 420 rpm and the stirring time is 60 min.

[0053] Specifically, the single-stage impregnation method employs full impregnation.

[0054] Specifically, the drying temperature of the heat-collecting constant-temperature magnetic stirrer is 90℃, the stirring time for the fifth stirring is 2.5h, and the stirring speed is 250 rpm.

[0055] Specifically, the roasting temperature is 420℃ and the roasting time is 3 hours.

[0056] S4. The denitrification catalyst obtained in S3 is loaded into the SCR reactor, and pretreated flue gas (flue gas temperature 180℃, space velocity 36000h) is introduced. -1 After stable operation for 2 hours, three parallel experiments were set up, and the following operating conditions were used for testing: 1. Continuously introduce 10% water vapor by volume into the SCR reactor for 10 hours; 2. Continuously introduce 100 ppm SO2 into the SCR reactor for 50 h; 3. Without introducing water vapor and SO2, maintain continuous operation at low temperature for 500 hours; 4. Simultaneously introduce 10% water vapor and 100 ppm SO2 into the SCR reactor for 100 hours, then stop introducing the water vapor and SO2.

[0057] During the experiment, the denitrification efficiency of each group of catalysts was tested, and X-ray photoelectron spectroscopy (XPS) was used to characterize and analyze the catalysts after the reaction.

[0058] Example 2 The steps of the preparation method in this embodiment are the same as those in Example 1, except that: In S2, the amount of deionized water is 3300 mol (corresponding to a volume of 59.4 L at room temperature and pressure); the amount of PEG-400 dispersant is 3.3 mol (corresponding to a mass of 1320 g); and the amount of TiO2 powder is 3.3 mol (corresponding to a mass of 264 g). The silica sol with a solid content of 30% has a mass of 26g; The stirring speed for the first, second, and third stirring operations was 500 prm, and the stirring time was 45 min for each operation.

[0059] In S3, the amount of manganese acetate tetrahydrate (Mn(CH3COO)2•4H2O) is 0.9 mol (corresponding to a mass of 259 g); the amount of thulium nitrate hexahydrate (Tm(NO3)3•6H2O) is 0.1 mol (corresponding to a mass of 46.3 g). The stirring speed for the fourth stirring was 500 prm, and the stirring time was 50 min. The fifth stirring was performed at a stirring speed of 350 prm for 3.5 hours. The calcination temperature is 360℃ and the calcination time is 4 hours; In S4, the flue gas temperature is 220°C.

[0060] Example 3 The preparation method in this embodiment is the same as that in Example 1, except that: In S2, the amount of deionized water is 800 mol (corresponding to a volume of 14.4 L at room temperature and pressure); the amount of PEG-400 dispersant is 2 mol (corresponding to a mass of 800 g); and the amount of TiO2 powder is 1 mol (corresponding to a mass of 80 g). The silica sol with a solid content of 30% has a mass of 12g; The stirring speed for the first, second, and third stirring operations was 750 prpm, and the stirring time was 60 min for each operation.

[0061] In S3, manganese nitrate (Mn(NO3)2) is used instead of manganese acetate tetrahydrate (Mn(CH3COO)2•4H2O), and the amount of manganese nitrate (Mn(NO3)2) is 0.34 mol (corresponding to a mass of 61 g). Yttrium chloride hexahydrate (YCl3•6H2O) was used instead of thulium acetate hexahydrate (Tm(CH3COO)3•6H2O), and the amount of yttrium chloride hexahydrate (YCl3•6H2O) was 0.16 mol (corresponding to a mass of 48.6 g). The stirring speed for the fourth stirring was 600 prm, and the stirring time was 40 min. The fifth stirring was performed at a speed of 500 rpm for 4 hours. The roasting temperature is 490℃ and the roasting time is 2 hours.

[0062] In S5, the flue gas temperature is 280°C.

[0063] Comparative Example 1 This comparative example provides a method for preparing a catalyst, comprising the following steps: S1. Fiberglass mat is selected as the skeleton material. It is manufactured into a corrugated board using a molding liquid and molding process, and then stacked with a flat plate to form a 500×300×300mm sheet with a geometric specific surface area of ​​1200 m². 2 / m 3 Functional unit with a porosity of 75%.

[0064] Specifically, the corrugated plate has a corrugation height of 10mm and a corrugation pitch of 15mm.

[0065] S2. Prepare 1200 mol of deionized water (equivalent to 21.6 L at room temperature and pressure), then add 0.5 mol of PEG-400 dispersant (equivalent to 200 g), and stir with a magnetic stirrer until completely dissolved to obtain a first solution; add 1 mol of TiO2 powder (equivalent to 80 g) to the first solution, and stir with a magnetic stirrer a second time to obtain a second solution; then add 5 g of silica sol with a solid content of 30% to the second solution, and stir a third time until the silica sol and the second solution are fused to obtain a TiO2 suspension; Specifically, the stirring speed for the first, second, and third stirring is 300 rpm, and the stirring time is 30 min for each. Specifically, the TiO2 powder is anatase type with a purity of 99.5%.

[0066] S3. Prepare 0.3 mol of manganese acetate tetrahydrate (Mn(CH3COO)2•4H2O) (corresponding to a mass of 74 g), add it to the TiO2 suspension, and then perform a fourth stirring using a combination of ultrasonic and magnetic stirring to obtain an impregnation solution. Next, use a single impregnation method to load the impregnation solution onto the surface of the functional unit to obtain a modified functional unit. Place the modified functional unit in a heat-collecting constant-temperature magnetic stirrer and simultaneously perform a fifth stirring and heating drying. Then, place the dried modified functional unit in a muffle furnace for calcination to obtain the catalyst.

[0067] Specifically, the manganese acetate tetrahydrate (Mn(CH3COO)2•4H2O) is chemically pure with a purity of 99%. Specifically, the fourth stirring speed is 420 rpm and the stirring time is 60 min.

[0068] Specifically, the single-stage impregnation method employs full impregnation.

[0069] Specifically, the drying temperature of the heat-collecting constant-temperature magnetic stirrer is 90℃, the stirring time for the fifth stirring is 2.5h, and the stirring speed is 250 rpm.

[0070] Specifically, the roasting temperature is 420℃ and the roasting time is 3 hours.

[0071] S4. The catalyst obtained in S3 is loaded into the SCR reactor, and pretreated flue gas (flue gas temperature 180℃, space velocity 36000h-1) is introduced; the reactor is run stably for 2 hours, and then three parallel experiments are set up to test under the following conditions: 1. Continuously introduce 10% water vapor by volume into the SCR reactor for 10 hours; 2. Introduce SO2 at a concentration of 100 ppm into the SCR reactor for 50 h. 3. Without introducing water vapor and SO2, maintain continuous operation at low temperature for 200 hours; 4. Simultaneously introduce 10% water vapor and 100 ppm SO2 into the SCR reactor for 100 hours, then stop introducing the water vapor and SO2.

[0072] During the experiment, the denitrification efficiency of each group of catalysts was tested, and X-ray photoelectron spectroscopy (XPS) was used to characterize and analyze the catalysts after the reaction.

[0073] Comparative Example 2 A vanadium-titanium-based selective catalytic reduction (SCR) denitrification catalyst, widely used in industrial flue gas denitrification, was loaded into an SCR reactor, and pretreated flue gas (flue gas temperature 200℃, space velocity 36000 h⁻¹) was introduced. -1 After stable operation for 2 hours, three parallel experiments were set up, and the following operating conditions were used for testing: 1. Continuously introduce 10% water vapor by volume into the SCR reactor for 10 hours; 2. Introduce SO2 at a concentration of 100 ppm into the SCR reactor for 50 h. 3. Without introducing water vapor and SO2, maintain continuous operation at low temperature for 500 hours; 4. Simultaneously introduce 10% water vapor and 100 ppm SO2 into the SCR reactor for 100 hours, then stop introducing the water vapor and SO2.

[0074] During the experiment, the denitrification efficiency of each group of denitrification catalysts was measured, and X-ray photoelectron spectroscopy (XPS) was used to characterize and analyze the denitrification catalysts after the reaction. Specifically, the flue gas denitrification of Examples 1-3 and Comparative Examples 1-2 and the corresponding catalyst characterization results are shown in the table below.

[0075] Table 1. Flue gas denitrification status and corresponding catalyst characterization results

[0076]

[0077]

[0078] As can be seen from the denitrification performance tests and catalyst characterization results shown in Examples 1-3, the denitrification catalyst of the present invention has excellent low-temperature denitrification activity, high N2 selectivity and sulfur and water resistance, and can operate continuously and stably under low-temperature conditions. Its performance degradation is much lower than that of traditional catalysts, breaking through the technical bottleneck of easy deactivation of traditional low-temperature denitrification catalysts.

[0079] Comparative Example 1 uses an undoped Mn / TiO2 catalyst. Experimental data show that the low-temperature denitrification activity, N2 selectivity, and sulfur and water resistance of this catalyst are significantly inferior to the rare earth-doped catalyst of this invention. This shows that the doping of rare earth metal elements plays a key and irreplaceable role in regulating the surface electronic structure of the denitrification catalyst and improving its low-temperature catalytic performance.

[0080] Comparative Example 2 uses a vanadium-titanium-based catalyst widely used in the industrial field. The active temperature window of this catalyst is usually 300~400℃. Under the medium and low temperature flue gas conditions (150~300℃) specified in this invention, its denitrification activity is less than 50%, and its N2 selectivity and sulfur and water resistance are far lower than those of the catalyst of this invention, which cannot meet the actual application requirements of low temperature denitrification.

[0081] In summary, the denitrification catalyst of this invention combines high efficiency in flue gas denitrification with good wide temperature window adaptability, making it particularly suitable for denitrification scenarios of medium and low temperature flue gas (150~300℃). It has made a breakthrough improvement in the catalytic activity and stability of the denitrification catalyst in the low temperature range of <300℃, and its adaptability to complex medium and low temperature flue gas operating conditions with large load fluctuations has been significantly enhanced, solving the technical pain points of insufficient low temperature activity and poor operating condition adaptability of traditional catalysts.

[0082] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0083] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A rare earth-doped manganese-based low-temperature denitration catalyst, characterized in that, The denitrification catalyst comprises functional units consisting of alternating corrugated plates and flat plates, wherein the functional units are loaded with manganese-based active components supported by TiO2 powder.

2. The rare earth-doped manganese-based low-temperature denitration catalyst according to claim 1, characterized in that, The main component of the manganese-based active ingredient is manganese oxide, which is doped with a specific type of rare earth active ingredient.

3. The rare earth-doped manganese-based low-temperature denitration catalyst according to claim 2, characterized in that, The precursor of the manganese oxide is a soluble manganese salt.

4. The rare earth-doped manganese-based low-temperature denitration catalyst according to claim 2, characterized in that, The precursor of the rare earth active component is a soluble salt of the corresponding rare earth element.

5. A method for preparing a rare-earth-doped manganese-based low-temperature denitration catalyst according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Glass fiber mat is selected as the skeleton material. After being made into a corrugated plate by molding liquid and molding process, it is then stacked with flat plate to form a functional unit. S2. Take a specific amount of deionized water, then add a specific amount of dispersant to it, and stir for the first time until completely dissolved to obtain a first solution; add a specific amount of TiO2 powder to the first solution and stir for the second time to obtain a second solution; Then, a specific amount of binder is added to the second solution, and the mixture is stirred a third time until the binder is fused with the second solution to obtain a TiO2 suspension. S3. Take a specific amount of soluble manganese salt and a specific amount of soluble salt of rare earth elements, and add them sequentially to the TiO2 suspension. After stirring for the fourth time, an impregnation solution is obtained. The impregnation solution is loaded onto the surface of the functional unit using a single impregnation method to obtain a modified functional unit. The modified functional unit is then dried and calcined sequentially to obtain the denitrification catalyst.

6. The method for preparing a rare earth-doped manganese-based low-temperature denitration catalyst according to claim 5, characterized in that, In S2, the molar ratio of deionized water: dispersant: TiO2 powder is in the range of (800~1200): (0.5~2): 1; the mass of the binder is 5%~15% of the mass of TiO2 powder.

7. The method for preparing a rare earth-doped manganese-based low-temperature denitration catalyst according to claim 5, characterized in that, In S3, the molar ratio of rare earth metal ions in the soluble salt of the rare earth element to manganese ions in the soluble manganese salt is in the range of (0.1~0.5):

1.

8. The method for preparing a rare earth-doped manganese-based low-temperature denitration catalyst according to claim 7, characterized in that, In S3, the molar ratio of the sum of the molar numbers of rare earth metal ions and manganese ions to Ti ions is in the range of (0.3~0.5):

1.

9. The method for preparing a rare earth-doped manganese-based low-temperature denitration catalyst according to claim 5, characterized in that, In S3, the drying process adopts a method of simultaneous heating and drying with stirring; the drying temperature is 80~150℃, the stirring speed is 200~500 rpm, and the stirring time is 2~4h; the calcination process has a calcination temperature range of 350℃~500℃ and a calcination time of 2~4h.

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