Method for low-temperature regeneration of deactivated denitration catalysts

Abstract

The present application relates to a kind of low-temperature modification regeneration methods of deactivation denitration catalyst, belong to denitration catalyst recycling field.The steps of including dust cleaning, cleaning, drying, preparation active liquid, determining load, impregnation load, calcination and design use, wherein cleaning is carried out with alkaline solution, acid liquor and water to carry out ultrasonic-assisted bubble cleaning, preparation active liquid is divided into active liquid A prepared with Mn salt and Fe salt and active liquid B prepared with V compound, determining load is determined according to the temperature after regeneration, and the amount of MnO2, Fe2O3 and V2O5 is loaded, low-temperature modified regeneration denitration catalyst is obtained after being loaded by ultrasonic impregnation, and further according to the volume amount design of regeneration denitration catalyst use temperature.The method is used in middle-high section denitration catalyst, after deactivation, low-temperature modification regeneration is carried out, realizes the recycling of deactivation denitration catalyst and reduces the temperature of flue gas denitration, can simultaneously reduce denitration catalyst replacement cost and denitration operating energy consumption.

Description

Technical Field

[0001] This invention relates to a method for low-temperature modification and regeneration of deactivated denitration catalysts, belonging to the field of denitration catalyst recycling. Background Technology

[0002] Nitrogen oxides (NO) x NO is the primary air pollutant in my country. Selective catalytic reduction (SCR) technology, using NH3 as a reducing agent, can achieve NO reduction under the action of denitrification catalysts. x Ultra-low emissions. In 2019, the Ministry of Ecology and Environment and other departments successively issued opinions on ultra-low emission retrofitting for industries such as thermal power, steel, and coking, requiring that flue gas NO₂... x The emission concentration shall not exceed 50 mg / m³ of the ultra-low emission limit. 3 Nationwide, over 90% of flue gas denitrification uses SCR technology, resulting in a large demand for denitrification catalysts, but their service life is generally around 3 years. Deactivated denitrification catalysts are classified as HW50 hazardous waste, possessing both pollution and resource-related characteristics.

[0003] Currently, the commonly used denitrification catalysts in my country are medium- and high-temperature stage catalysts. However, the flue gas emission temperatures in industries such as steel, coking, glass, and cement are relatively low, often requiring secondary heating to meet the requirements of conventional denitrification catalysts. The cost of replacing denitrification catalysts and reheating flue gas constitutes a major portion of the cost of flue gas denitrification. Therefore, regenerating existing conventional medium- and high-temperature stage denitrification catalysts into low-temperature denitrification catalysts for reuse can reduce the replacement cost of denitrification catalysts and lower the energy consumption for flue gas heating, resulting in significant socio-economic benefits, as detailed below:

[0004] First, reduce the cost of replacing denitrification catalysts. In 2014, the former Ministry of Environmental Protection issued the "Notice on Strengthening the Supervision of Waste Flue Gas Denitrification Catalysts," encouraging the development of a number of utilization and disposal enterprises to quickly improve the regeneration, utilization, and disposal capacity of waste denitrification catalysts, thereby avoiding environmental pollution and resource waste. The regeneration of vanadium-titanium denitrification catalysts can not only solve the problem of hazardous waste disposal for enterprises and recycle the strategic metal resources of V, W, and Ti in waste denitrification catalysts, but also reduce carbon emissions from catalyst production, lowering the cost of denitrification catalysts by more than 30% while maintaining the same denitrification performance. Second, lower the denitrification temperature and reduce the cost of flue gas reheating. Heating low-temperature flue gas to the appropriate high-temperature range requires a large amount of energy. Lowering the flue gas denitrification temperature can not only reduce energy consumption and thus lower costs, but also reduce carbon emissions from energy consumption.

[0005] Therefore, reducing catalyst replacement costs and flue gas heating costs through low-temperature modification and regeneration of deactivated denitrification catalysts is an important way for enterprises to reduce flue gas denitrification costs.

[0006] Patent CN110013885A discloses a method for regenerating a denitrification catalyst, which uses a novel process of cleaning, chemical cleaning, and component impregnation as the main regeneration steps. It can be impregnated again without drying and calcination steps. The remaining initiator liquid also helps the active replenishment liquid to adhere and reduce the SO2 oxidation rate. However, the application target of its regenerated denitrification catalyst is still mainly based on the original operating temperature, which cannot meet the requirements of low-temperature denitrification performance.

[0007] Patent CN114471746A discloses a method for regenerating SCR denitration catalysts. The method involves treating the deactivated catalyst, reacting it with sulfuric acid to obtain a replenishing solution, immersing the deactivated catalyst in the replenishing solution, neutralizing it with ammonia, hydrolyzing it, and then calcining it to obtain the regenerated denitration catalyst. This method not only recovers and reuses the spent catalyst but also allows the extracted effective components to be directly used in the regeneration process of the deactivated catalyst. However, it regenerates powdered catalysts, requiring secondary sample preparation, resulting in low powder utilization. Although the support strength of the regenerated denitration catalyst is higher than that of conventional regeneration processes, its cost is significantly increased. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides a method for low-temperature modification and regeneration of deactivated denitrification catalysts. This method involves low-temperature modification and regeneration of deactivated denitrification catalysts used at medium and high temperatures. Poisoning factors in the deactivated denitrification catalyst are removed through ash removal and cleaning. Then, active components are quantitatively loaded according to the target operating temperature for regeneration. Finally, the catalyst is designed for low-temperature flue gas denitrification, enabling high-value recycling of the deactivated denitrification catalyst. This reduces both the cost of replacing the denitrification catalyst and the energy consumption for denitrification.

[0009] This invention is achieved through the following technical solution:

[0010] A method for low-temperature modification and regeneration of a deactivated denitration catalyst, characterized by comprising the steps of descaling, washing, drying, preparing an active solution, determining the loading rate, impregnation loading, calcination, and designing the application, as shown in the appendix. Figure 1 As shown.

[0011] The dust removal process involves alternating between negative pressure suction and positive pressure purging to remove dust from the surface and pores until the porosity reaches 99.0% or higher. The negative pressure is 20–500 kPa, and the positive pressure is 0.2–1.0 MPa. The dust deposited on the catalyst surface and pores can be dispersed and collected by negative pressure suction and positive pressure purging.

[0012] The cleaning process involves sequentially applying an alkaline solution, an acid solution, and water using ultrasonic-assisted bubbling. The alkaline cleaning uses a mixture of NaOH and polyoxyethylene fatty alcohol ether at 40–50°C for 30–45 minutes. The NaOH concentration is 2.0–8.0 wt.%, and the polyoxyethylene fatty alcohol ether concentration is 0.5–2.0 wt.%. The alkaline solution removes acidic poisoning agents such as arsenic from the deactivated denitrification catalyst, while the surfactant polyoxyethylene fatty alcohol ether deeply removes insoluble components such as dust and organic matter from the micropores. The acid cleaning process involves using a mixture of H2SO4 and fatty acid amide at 40–60°C for 30–60 minutes, wherein the concentration of H2SO4 is 1.0–6.0 wt.% and the concentration of fatty acid amide is 0.5–2.0 wt.%. This process removes elements such as alkali, alkaline earth metals, and Hg from the deactivated denitrification catalyst. The surfactant fatty acid amide also helps to penetrate and clean microporous poisoning factors. The water cleaning process involves rinsing with deionized water 1–3 times to remove residual cleaning solutions from the alkaline and acid cleaning processes.

[0013] The drying process involves drying the cleaned denitrification catalyst at 60–120°C with a forced air temperature until the water content is ≤6 wt.%, which helps in the subsequent impregnation and loading of the active liquid.

[0014] Further, the active solution is prepared by using Mn salt and Fe salt to prepare active solution A, and using compound V to prepare active solution B at 50-80°C; the concentration of Mn ions in active solution A is 1-5 wt.%, the concentration of Fe ions is 0-2.5 wt.%, and the concentration of polyoxyethylene fatty alcohol ether is 1-3 wt.%; the concentration of V ions in active solution B is 2-8 wt.%, and the molar ratio of monoethanolamine to compound V is 1:(0.8-1.2); the Mn salt is one or both of Mn(CH3COO)2 and Mn(NO3)2, the Fe salt is one or both of FeOH(CH3COO)2 and Fe(NO3)3, and the vanadium compound is one or both of NH4VO3 and V2O5. The Mn salt and Fe salt used can decompose at a relatively low temperature to form oxides, leaving no harmful components. Both NH4VO3 and V2O5 can be well dissolved with monoethanolamine as a solubilizer. By increasing the concentration of monoethanolamine, when a higher concentration of V needs to be prepared in active solution B, monoethanolamine can be mixed with vanadium compounds to dissolve first, and then diluted with water to the target concentration, thus solving the problem of low solubility of vanadium compounds.

[0015] The determination of the loading amount is based on the operating temperature after regeneration, which determines the amount of MnO2, Fe2O3, and V2O5 loaded. When the target operating temperature is 150–200°C, the loading amounts of MnO2, Fe2O3, and V2O5 are 0.5–2.0 wt.%, 0.2–1.5 wt.%, and 3.0–4.5 wt.%, respectively; when the target operating temperature is 200–250°C, the loading amounts of MnO2, Fe2O3, and V2O5 are 0–1.5 wt.%, 0–1.0 wt.%, and 2.5–3.0 wt.%, respectively; and when the target operating temperature is 250–300°C, the loading amounts of MnO2, Fe2O3, and V2O5 are 0–1.0 wt.%, 0–0.5 wt.%, and 2.0–2.5 wt.%, respectively. The loading of the active material ensures that the catalyst exhibits good denitrification activity at the corresponding temperature, meeting the design temperature requirements. Mn and Fe have good denitrification activity at low temperatures, and the appropriate addition of Mn and Fe can form a synergistic denitrification with V, improving the low-temperature denitrification efficiency.

[0016] The impregnation loading can be optionally performed by placing the dried catalyst in active liquid A, ultrasonically impregnating it for 15-30 min, removing it and drying it at 100-150℃; or by placing the catalyst in active liquid B, ultrasonically impregnating it for 15-30 min, removing it and drying it at 100-150℃, optionally repeating this process 1-3 times. When the target operating temperature is >200℃, the loading of Mn and Fe can be selectively performed; when the target operating temperature is ≤200℃, Mn and Fe need to be loaded to improve the low-temperature denitrification activity. First impregnating with active liquid A, and then loading with active liquid B after drying, allows the Mn and Fe components to occupy the micropores and deep pores of the catalyst support, while the V component is loaded on the surface of the catalyst support. This can both alleviate the poisoning of Mn and Fe components by poisoning factors such as SO2, and help the surface V component to fully exert its denitrification activity.

[0017] Once the loading amount is determined, the quantitative loading of the active component can be achieved during the loading process based on the water absorption rate of the carrier after cleaning and drying and the concentration of the active liquid. When the water content of the carrier is controlled below 6%, the maximum water absorption can reach 45% of the carrier's own weight. By controlling the impregnation time, the water absorption can be further adjusted to between 20% and 45%. That is, the impregnation loading step mainly achieves the quantitative loading of the active material by controlling the concentration of the active liquid and the water absorption rate. The calcination involves treating the catalyst after impregnation and loading of the active component at 280–420°C for 30–90 minutes.

[0018] The design utilizes the volumetric volume of the regenerated denitrification catalyst based on its operating temperature. For temperatures decreasing by 0–60°C from the original operating temperature, the original volume can be used; for temperatures decreasing by 60–120°C, 1.1–1.3 times the original volume can be used; and for temperatures decreasing by more than 120°C, 1.3–1.6 times the original volume can be used. The original operating temperature refers to the designed denitrification temperature before regeneration of the deactivated denitrification catalyst. The original operating temperature of the deactivated denitrification catalyst is in the medium-high temperature range. At high temperatures, the denitrification reaction rate is faster, and the designed catalyst volume is relatively small. When the reaction temperature is lower, the designed volume needs to be increased accordingly. Because the regeneration process reloads the active material, it can load more V active material and appropriately increase Mn and Fe components. Therefore, when the operating temperature is reduced by 0–60°C, the original volume can still be used. When the temperature reduction exceeds 60°C, the catalyst volume needs to be increased accordingly.

[0019] The beneficial technical effects of this invention are:

[0020] (1) The method described in this invention regenerates the denitrification catalyst used in the middle and high stages by low-temperature modification after deactivation, thereby realizing the recycling of the deactivated denitrification catalyst and reducing the flue gas denitrification temperature. This can simultaneously reduce the cost of replacing the denitrification catalyst and the energy consumption of denitrification operation.

[0021] (2) The method described in this invention combines the regeneration process with the intended use after regeneration. It achieves quantitative loading of active material by controlling the concentration of active liquid and the water absorption rate of catalyst carrier, and can be precisely regenerated according to the target use temperature.

[0022] (3) The method of the present invention loads Mn and Fe components mainly on the micropores and deep pores of the catalyst support, while loading V component on the surface of the catalyst support. This can not only alleviate the poisoning of Mn and Fe components by SO2 and other poisoning factors, but also help the surface V component to fully exert its denitrification activity. Attached Figure Description

[0023] Figure 1 This is a flowchart of the overall process for low-temperature modification and regeneration of this invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art will fully understand the invention even without these detailed descriptions. This invention covers any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of the invention as defined in the claims.

[0025] Implementation Case 1

[0026] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 20 kPa and the positive pressure is 0.2 MPa.

[0027] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 40°C for 45 min (NaOH concentration: 8.0 wt.%) and polyoxyethylene fatty alcohol ether concentration: 2.0 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 40°C for 60 min (H2SO4 concentration: 6.0 wt.%) and fatty acid amide concentration: 2.0 wt.%); and rinsing three times with deionized water. The cleaned denitrification catalyst was then dried at 60°C with forced air until the moisture content was ≤6 wt.%.

[0028] The active solution was prepared by using Mn salt and Fe salt to prepare active solution A, and using compound V to prepare active solution B at 50°C. The concentration of Mn ions in active solution A was 5 wt.%, the concentration of Fe ions was 2.5 wt.%, and the concentration of polyoxyethylene fatty alcohol ether was 3 wt.%. The concentration of V ions in active solution B was 8 wt.%, and the molar ratio of monoethanolamine to compound V was 1:1.2. The Mn salt was Mn(CH3COO)2, the Fe salt was FeOH(CH3COO)2, and the vanadium compound was NH4VO3.

[0029] The determination of the loading amount is based on the operating temperature after regeneration, which determines the amount of MnO2, Fe2O3, and V2O5 loaded. The target operating temperature is 150℃, and the loading amounts of MnO2, Fe2O3, and V2O5 are 2.0 wt.%, 1.5 wt.%, and 4.5 wt.%, respectively.

[0030] The impregnation loading can optionally involve placing the dried catalyst in active liquid A, ultrasonically impregnating it for 30 min, removing it, and drying it at 100°C; or placing the catalyst in active liquid B, ultrasonically impregnating it for 30 min, removing it, and drying it at 100°C, optionally repeating this process 3 times. The calcination involves treating the catalyst impregnated with the active component at 420°C for 90 min.

[0031] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, reducing the original operating temperature by 70°C and using it at 1.1 times the original volume; the original operating temperature is the designed denitrification temperature before the deactivated denitrification catalyst is regenerated.

[0032] Implementation Case 2

[0033] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 50 kPa and the positive pressure is 0.3 MPa.

[0034] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 42°C for 43 min (NaOH concentration 7.0 wt.% and polyoxyethylene fatty alcohol ether concentration 1.5 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 45°C for 55 min (H2SO4 concentration 5.0 wt.% and fatty acid amide concentration 1.5 wt.%); and rinsing three times with deionized water. The cleaned denitrification catalyst was then dried at 70°C with forced air until the moisture content was ≤6 wt.%.

[0035] The active solution was prepared by using Mn salt and Fe salt to prepare active solution A, and using V compound to prepare active solution B at 55°C. The concentration of Mn ions in active solution A was 4 wt.%, the concentration of Fe ions was 2.5 wt.%, and the concentration of polyoxyethylene fatty alcohol ether was 2.5 wt.%. The concentration of V ions in active solution B was 7 wt.%, and the molar ratio of monoethanolamine to V compound was 1:1.1. The Mn salt was Mn(NO3)2, the Fe salt was Fe(NO3)3, and the vanadium compound was V2O5.

[0036] The determination of the loading amount is based on the operating temperature after regeneration, which determines the amount of MnO2, Fe2O3, and V2O5 loaded. The target operating temperature is 160℃, and the loading amounts of MnO2, Fe2O3, and V2O5 are 1.5wt.%, 1.0wt.%, and 4.0wt.%, respectively.

[0037] The impregnation loading can optionally involve placing the dried catalyst in active liquid A, ultrasonically impregnating it for 25 min, removing it, and drying it at 110°C; or placing the catalyst in active liquid B, ultrasonically impregnating it for 25 min, removing it, and drying it at 110°C, optionally repeating this process 3 times. The calcination involves treating the catalyst impregnated with the active component at 400°C for 30 min.

[0038] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, with the operating temperature reduced by 200°C and the volume used at 1.5 times the original volume; the original operating temperature is the designed denitrification temperature before the deactivated denitrification catalyst is regenerated.

[0039] Implementation Case 3

[0040] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 100 kPa and the positive pressure is 0.4 MPa.

[0041] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 44°C for 41 min (NaOH concentration 6.0 wt.% and polyoxyethylene fatty alcohol ether concentration 1.0 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 50°C for 50 min (H2SO4 concentration 4.0 wt.% and fatty acid amide concentration 1.0 wt.%); and rinsing three times with deionized water. The cleaned denitrification catalyst was then dried at 80°C with forced air until the moisture content was ≤6 wt.%.

[0042] The active solution is prepared by using Mn salt and Fe salt to prepare active solution A, and using compound V to prepare active solution B at 60°C. The concentration of Mn ions in active solution A is 3 wt.%, the concentration of Fe ions is 2.0 wt.%, and the concentration of polyoxyethylene fatty alcohol ether is 2 wt.%. The concentration of V ions in active solution B is 8 wt.%, and the molar ratio of monoethanolamine to compound V is 1:1.2. The Mn salts are Mn(CH3COO)2 and Mn(NO3)2, the Fe salts are FeOH(CH3COO)2 and Fe(NO3)3, and the vanadium compound is NH4VO3.

[0043] The determination of the loading amount is based on the operating temperature after regeneration, which determines the amount of MnO2, Fe2O3, and V2O5 loaded. The target operating temperature is 170℃, and the loading amounts of MnO2, Fe2O3, and V2O5 are 1.0 wt.%, 0.5 wt.%, and 3.5 wt.%, respectively.

[0044] The impregnation loading can optionally involve placing the dried catalyst in active liquid A, ultrasonically impregnating it for 25 min, removing it, and drying it at 120°C; or placing the catalyst in active liquid B, ultrasonically impregnating it for 25 min, removing it, and drying it at 120°C, and optionally repeating this process twice. The calcination involves treating the catalyst impregnated with the active component at 380°C for 45 min.

[0045] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, with the operating temperature reduced by 220°C and the volume used at 1.6 times the original volume. The original operating temperature is the denitrification temperature designed for use before the deactivated denitrification catalyst is regenerated.

[0046] Implementation Case 4

[0047] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 150 kPa and the positive pressure is 0.5 MPa.

[0048] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 46°C for 39 min (NaOH concentration: 5.0 wt.%) and polyoxyethylene fatty alcohol ether concentration: 0.5 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 55°C for 45 min (H2SO4 concentration: 3.0 wt.%) and fatty acid amide concentration: 0.5 wt.%); and rinsing three times with deionized water. The cleaned denitrification catalyst was then dried at 90°C with forced air until the moisture content was ≤6 wt.%.

[0049] The active solution is prepared by using Mn salt and Fe salt to prepare active solution A, and using V compound to prepare active solution B at 65°C. The concentration of Mn ions in active solution A is 2 wt.%, the concentration of Fe ions is 1 wt.%, and the concentration of polyoxyethylene fatty alcohol ether is 1 wt.%. The concentration of V ions in active solution B is 6 wt.%, and the molar ratio of monoethanolamine to V compound is 1:1. The Mn salt is Mn(NO3)2, the Fe salt is Fe(NO3)3, and the vanadium compounds are NH4VO3 and V2O5.

[0050] The determination of the loading amount is based on the operating temperature after regeneration, which determines the amount of MnO2, Fe2O3, and V2O5 loaded. The target operating temperature is 180℃, and the loading amounts of MnO2, Fe2O3, and V2O5 are 0.5wt.%, 0.2wt.%, and 3.0wt.%, respectively.

[0051] The impregnation loading can optionally involve placing the dried catalyst in active liquid A, ultrasonically impregnating it for 25 min, removing it, and drying it at 130°C; or placing the catalyst in active liquid B, ultrasonically impregnating it for 25 min, removing it, and drying it at 130°C, optionally repeating this process twice. The calcination involves treating the catalyst impregnated with the active component at 360°C for 60 min.

[0052] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, with the operating temperature reduced by 100°C and the volume used at 1.3 times the original volume; the original operating temperature is the designed denitrification temperature before the deactivated denitrification catalyst is regenerated.

[0053] Implementation Case 5

[0054] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 200 kPa and the positive pressure is 0.6 MPa.

[0055] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 48°C for 37 min (NaOH concentration: 4.0 wt.%) and polyoxyethylene fatty alcohol ether concentration: 0.5 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 60°C for 40 min (H2SO4 concentration: 2.0 wt.%) and fatty acid amide concentration: 0.5 wt.%); and rinsing three times with deionized water. The cleaned denitrification catalyst was then dried at 100°C with forced air until the moisture content was ≤6 wt.%.

[0056] The active solution was prepared by using Mn salt and Fe salt to prepare active solution A, and using compound V to prepare active solution B at 70°C. The concentration of Mn ions in active solution A was 2 wt.%, the concentration of Fe ions was 1 wt.%, and the concentration of polyoxyethylene fatty alcohol ether was 1 wt.%. The concentration of V ions in active solution B was 8 wt.%, and the molar ratio of monoethanolamine to compound V was 1:1.2. The Mn salt was Mn(CH3COO)2, the Fe salt was FeOH(CH3COO)2, and the vanadium compound was NH4VO3.

[0057] The determination of the load amount is based on the operating temperature after regeneration, which determines the amount of MnO2, Fe2O3, and V2O5 loaded. The target operating temperature is 190℃, and the loading amounts of MnO2, Fe2O3, and V2O5 are 0.5wt.%, 0.2wt.%, and 4.5wt.%, respectively.

[0058] The impregnation loading can optionally involve placing the dried catalyst in active liquid A, ultrasonically impregnating it for 30 min, removing it, and drying it at 140°C; or placing the catalyst in active liquid B, ultrasonically impregnating it for 30 min, removing it, and drying it at 140°C, and optionally repeating this process once. The calcination involves treating the catalyst impregnated with the active component at 340°C for 75 min.

[0059] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, reducing the original operating temperature by 90°C and using 1.3 times the original volume; the original operating temperature is the designed denitrification temperature before the deactivated denitrification catalyst is regenerated.

[0060] Implementation Case 6

[0061] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 250 kPa and the positive pressure is 0.7 MPa.

[0062] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 50°C for 35 min, where the NaOH concentration was 5.0 wt.% and the polyoxyethylene fatty alcohol ether concentration was 0.5 wt.%; cleaning with a mixture of H2SO4 and fatty acid amide at 60°C for 35 min, where the H2SO4 concentration was 3.0 wt.% and the fatty acid amide concentration was 0.5 wt.%; and rinsing three times with deionized water. The cleaned denitrification catalyst was then dried at 110°C with forced air until the moisture content was ≤6 wt.%.

[0063] The active solution is prepared by using Mn salt and Fe salt to prepare active solution A, and using V compound to prepare active solution B at 75°C. The concentration of Mn ions in active solution A is 2 wt.%, the concentration of Fe ions is 1 wt.%, and the concentration of polyoxyethylene fatty alcohol ether is 1 wt.%. The concentration of V ions in active solution B is 4 wt.%, and the molar ratio of monoethanolamine to V compound is 1:0.8. The Mn salt is Mn(NO3)2, the Fe salt is Fe(NO3)3, and the vanadium compound is V2O5.

[0064] The determination of the loading amount is based on the operating temperature after regeneration, which determines the amount of MnO2, Fe2O3, and V2O5 loaded. The target operating temperature is 200℃, and the loading amounts of MnO2, Fe2O3, and V2O5 are 0.5wt.%, 0.2wt.%, and 3.0wt.%, respectively.

[0065] The impregnation loading can optionally involve placing the dried catalyst in active liquid A, ultrasonically impregnating it for 25 min, removing it, and drying it at 150°C; or placing the catalyst in active liquid B, ultrasonically impregnating it for 25 min, removing it, and drying it at 150°C, optionally repeating this process twice. The calcination involves treating the catalyst impregnated with the active component at 320°C for 75 min.

[0066] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, reducing the original operating temperature by 80°C and using 1.2 times the original volume; the original operating temperature is the designed denitrification temperature before the deactivated denitrification catalyst is regenerated.

[0067] Implementation Case 7

[0068] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: ash removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The ash removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 300 kPa and the positive pressure is 0.8 MPa.

[0069] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 49°C for 33 min (NaOH concentration 6.0 wt.% and polyoxyethylene fatty alcohol ether concentration 0.5 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 60°C for 30 min (H2SO4 concentration 4.0 wt.% and fatty acid amide concentration 0.5 wt.%); and rinsing twice with deionized water. The cleaned denitrification catalyst was then dried at 120°C with forced air until the moisture content was ≤6 wt.%.

[0070] The active solution was prepared by using compound V at 80°C to prepare active solution B; the concentration of V ions in active solution B was 5 wt.%, and the molar ratio of monoethanolamine to compound V was 1:0.9; the vanadium compounds were NH4VO3 and V2O5.

[0071] The determined load amount is based on the operating temperature after regeneration, which is the amount of V2O5 loaded. The target operating temperature is 210℃, and the V2O5 load amount is 3.0 wt.%.

[0072] The impregnation loading involves ultrasonically impregnating the dried catalyst active liquid B for 20 minutes, removing it, and drying it at 100°C. Optionally, this process can be repeated twice. The calcination involves treating the catalyst with the impregnated and loaded active components at 260°C for 90 minutes.

[0073] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, reducing the original operating temperature by 80°C and using 1.2 times the original volume; the original operating temperature is the designed denitrification temperature before the deactivated denitrification catalyst is regenerated.

[0074] Implementation Case 8

[0075] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 350 kPa and the positive pressure is 0.9 MPa.

[0076] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 47°C for 31 min (NaOH concentration 7.0 wt.% and polyoxyethylene fatty alcohol ether concentration 1.0 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 55°C for 60 min (H2SO4 concentration 5.0 wt.% and fatty acid amide concentration 1.0 wt.%); and rinsing twice with deionized water. The cleaned denitrification catalyst was then dried at 65°C with forced air until the moisture content was ≤6 wt.%.

[0077] The active solution is prepared by using Mn salt and Fe salt to prepare active solution A, and using compound V to prepare active solution B at 50°C. The concentration of Mn ions in active solution A is 3 wt.%, the concentration of Fe ions is 1.5 wt.%, and the concentration of polyoxyethylene fatty alcohol ether is 2 wt.%. The concentration of V ions in active solution B is 5 wt.%, and the molar ratio of monoethanolamine to compound V is 1:0.8. The Mn salts are Mn(CH3COO)2 and Mn(NO3)2, the Fe salts are FeOH(CH3COO)2 and Fe(NO3)3, and the vanadium compound is V2O5.

[0078] The determination of the loading amount is based on the operating temperature after regeneration, which determines the amount of MnO2, Fe2O3, and V2O5 loaded. The target operating temperature is 220℃, and the loading amounts of MnO2, Fe2O3, and V2O5 are 1.0 wt.%, 0.5 wt.%, and 2.8 wt.%, respectively.

[0079] The impregnation loading can optionally involve placing the dried catalyst in active liquid A, ultrasonically impregnating it for 15 min, removing it, and drying it at 110°C; or placing the catalyst in active liquid B, ultrasonically impregnating it for 15 min, removing it, and drying it at 110°C, optionally repeating this process twice. The calcination involves treating the catalyst impregnated with the active component at 280°C for 60 min.

[0080] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, reducing the original operating temperature by 160°C and using 1.4 times the original volume; the original operating temperature is the designed denitrification temperature before the deactivated denitrification catalyst is regenerated.

[0081] Implementation Case 9

[0082] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 400 kPa and the positive pressure is 1.0 MPa.

[0083] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 45°C for 32 min (NaOH concentration: 8.0 wt.%) and polyoxyethylene fatty alcohol ether concentration: 2.0 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 55°C for 55 min (H2SO4 concentration: 6.0 wt.%) and fatty acid amide concentration: 2.0 wt.%); and rinsing twice with deionized water. The cleaned denitrification catalyst was then dried at 75°C with forced air until the moisture content was ≤6 wt.%.

[0084] The active solution was prepared by using Mn salt and Fe salt to prepare active solution A, and using compound V to prepare active solution B at 55°C. The concentration of Mn ions in active solution A was 4 wt.%, the concentration of Fe ions was 2.5 wt.%, and the concentration of polyoxyethylene fatty alcohol ether was 3 wt.%. The concentration of V ions in active solution B was 5 wt.%, and the molar ratio of monoethanolamine to compound V was 1:0.9. The Mn salt was Mn(CH3COO)2, the Fe salt was FeOH(CH3COO)2, and the vanadium compound was NH4VO3.

[0085] The determination of the loading amount is based on the operating temperature after regeneration, which determines the amount of MnO2, Fe2O3, and V2O5 loaded. The target operating temperature is 230℃, and the loading amounts of MnO2, Fe2O3, and V2O5 are 1.5wt.%, 1.0wt.%, and 2.5wt.%, respectively.

[0086] The impregnation loading can optionally involve placing the dried catalyst in active liquid A, ultrasonically impregnating it for 15 min, removing it, and drying it at 120°C; or placing the catalyst in active liquid B, ultrasonically impregnating it for 15 min, removing it, and drying it at 120°C, optionally repeating this process twice. The calcination involves treating the catalyst impregnated with the active component at 300°C for 60 min.

[0087] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, reducing the original operating temperature by 70°C and using it at 1.1 times the original volume; the original operating temperature is the designed denitrification temperature before the deactivated denitrification catalyst is regenerated.

[0088] Implementation Case 10

[0089] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 450 kPa and the positive pressure is 0.6 MPa.

[0090] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 43°C for 34 min (NaOH concentration 3.0 wt.% and polyoxyethylene fatty alcohol ether concentration 1.0 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 50°C for 50 min (H2SO4 concentration 1.0 wt.% and fatty acid amide concentration 1.0 wt.%); and rinsing once with deionized water. The cleaned denitrification catalyst was then dried at 85°C with forced air until the moisture content was ≤6 wt.%.

[0091] The active solution is prepared by using Mn salt to prepare active solution A and using V compound to prepare active solution B at 60°C; the concentration of Mn ions in active solution A is 2 wt.%, and the concentration of polyoxyethylene fatty alcohol ether is 2 wt.%; the concentration of V ions in active solution B is 5 wt.%, and the molar ratio of monoethanolamine to V compound is 1:0.9; the Mn salt is Mn(NO3)2, and the vanadium compound is V2O5.

[0092] The load amount is determined based on the operating temperature after regeneration, which is 240°C. The load amounts of MnO2 and V2O5 are 0.5 wt.% and 2.6 wt.%, respectively.

[0093] The impregnation loading can optionally involve placing the dried catalyst in active liquid A, ultrasonically impregnating it for 15 min, removing it, and drying it at 130°C; or placing the catalyst in active liquid B, ultrasonically impregnating it for 15 min, removing it, and drying it at 130°C, optionally repeating this process twice. The calcination involves treating the catalyst impregnated with the active component at 300°C for 60 min.

[0094] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, reducing the original operating temperature by 140°C and using 1.5 times the original volume; the original operating temperature is the designed denitrification temperature before the deactivated denitrification catalyst is regenerated.

[0095] Implementation Case 11

[0096] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 500 kPa and the positive pressure is 0.5 MPa.

[0097] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 41°C for 36 min (NaOH concentration: 2.0 wt.%) and polyoxyethylene fatty alcohol ether concentration: 1.0 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 50°C for 45 min (H2SO4 concentration: 1.0 wt.%) and fatty acid amide concentration: 1.0 wt.%); and rinsing once with deionized water. The cleaned denitrification catalyst was then dried at 95°C with forced air until the moisture content was ≤6 wt.%.

[0098] The active solution was prepared by using compound V at 65°C to prepare active solution B; the concentration of V ions in active solution B was 7 wt.%, and the molar ratio of monoethanolamine to compound V was 1:1; the vanadium compounds were NH4VO3 and V2O5.

[0099] The determined load amount is based on the operating temperature after regeneration, which is the amount of V2O5 loaded. The target operating temperature is 250°C, and the V2O5 load amount is 2.7 wt.%.

[0100] The impregnation loading involves placing the dried catalyst in active liquid B, ultrasonically impregnating it for 15 minutes, removing it, and drying it at 140°C. Optionally, this process can be repeated once. The calcination involves treating the catalyst with the impregnated and loaded active components at 320°C for 60 minutes.

[0101] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, with the original operating temperature reduced by 20°C while using the original volumetric design. The original operating temperature is the denitrification temperature designed for use before the deactivated denitrification catalyst is regenerated.

[0102] Implementation Case 12

[0103] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: ash removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The ash removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 40 kPa and the positive pressure is 0.25 MPa.

[0104] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 45°C for 38 min, where the NaOH concentration was 4.0 wt.% and the polyoxyethylene fatty alcohol ether concentration was 1.0 wt.%; cleaning with a mixture of H2SO4 and fatty acid amide at 45°C for 40 min, where the H2SO4 concentration was 1.0 wt.% and the fatty acid amide concentration was 1.0 wt.%; and rinsing once with deionized water. The cleaned denitrification catalyst was then dried at 105°C with forced air until the moisture content was ≤6 wt.%.

[0105] The active solution was prepared by using compound V at 70°C to prepare active solution B; the concentration of V ions in active solution B was 6 wt.%, and the molar ratio of monoethanolamine to compound V was 1:1.2; the vanadium compound was V2O5.

[0106] The determined load amount is based on the regenerated operating temperature to determine the amount of V2O5. The target operating temperature is 260℃, and the V2O5 load amount is 2.5 wt.%.

[0107] The impregnation loading involves placing the dried catalyst in active liquid B, ultrasonically impregnating it for 30 minutes, removing it, and drying it at 150°C. Optionally, this process can be repeated once. The calcination involves treating the catalyst with the impregnated and loaded active components at 260°C for 90 minutes.

[0108] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, with the original operating temperature reduced by 0°C and the original volumetric design applied. The original operating temperature is the denitrification temperature designed for use before the deactivated denitrification catalyst is regenerated.

[0109] Implementation Case 13

[0110] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 80 kPa and the positive pressure is 0.35 MPa.

[0111] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 45°C for 30 min (NaOH concentration 7.0 wt.% and polyoxyethylene fatty alcohol ether concentration 2.0 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 45°C for 35 min (H2SO4 concentration 5.0 wt.% and fatty acid amide concentration 2.0 wt.%); and rinsing twice with deionized water. The cleaned denitrification catalyst was then dried at 115°C with forced air until the moisture content was ≤6 wt.%.

[0112] The active solution was prepared by using Mn salt and Fe salt to prepare active solution A, and using compound V to prepare active solution B at 75°C. The concentration of Mn ions in active solution A was 1 wt.%, the concentration of Fe ions was 1.0 wt.%, and the concentration of polyoxyethylene fatty alcohol ether was 2 wt.%. The concentration of V ions in active solution B was 6 wt.%, and the molar ratio of monoethanolamine to compound V was 1:1.1. The Mn salts were Mn(CH3COO)2 and Mn(NO3)2, the Fe salts were FeOH(CH3COO)2 and Fe(NO3)3, and the vanadium compound was NH4VO3.

[0113] The determination of the loading amount is based on the operating temperature after regeneration, which determines the amount of MnO2, Fe2O3, and V2O5 loaded. The target operating temperature is 270℃, and the loading amounts of MnO2, Fe2O3, and V2O5 are 0.5wt.%, 0.2wt.%, and 2.3wt.%, respectively.

[0114] The impregnation loading can optionally involve placing the dried catalyst in active liquid A, ultrasonically impregnating it for 15 min, removing it, and drying it at 130°C; or placing the catalyst in active liquid B, ultrasonically impregnating it for 20 min, removing it, and drying it at 130°C, and optionally repeating this process once. The calcination involves treating the catalyst after impregnation and loading with the active component at 320°C for 90 min.

[0115] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, with the original operating temperature reduced by 30°C while using the original volumetric design. The original operating temperature is the denitrification temperature designed for use before the deactivated denitrification catalyst is regenerated.

[0116] Implementation Case 14

[0117] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 120 kPa and the positive pressure is 0.45 MPa.

[0118] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 50°C for 30 min (NaOH concentration: 8.0 wt.%) and polyoxyethylene fatty alcohol ether concentration: 2.0 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 40°C for 30 min (H2SO4 concentration: 5.0 wt.%) and fatty acid amide concentration: 2.0 wt.%); and rinsing twice with deionized water. The cleaned denitrification catalyst was then dried at 120°C with forced air until the moisture content was ≤6 wt.%.

[0119] The active solution is prepared by using Mn salt and Fe salt to prepare active solution A, and using V compound to prepare active solution B at 80°C; the concentration of Mn ions in active solution A is 3 wt.%, the concentration of Fe ions is 2.0 wt.%, and the concentration of polyoxyethylene fatty alcohol ether is 1 wt.%; the concentration of V ions in active solution B is 2 wt.%, and the molar ratio of monoethanolamine to V compound is 1:0.8; the Mn salt is Mn(NO3)2, the Fe salt is Fe(NO3)3, and the vanadium compound is V2O5.

[0120] The determination of the loading amount is based on the operating temperature after regeneration, which determines the amount of MnO2, Fe2O3, and V2O5 loaded. The target operating temperature is 280℃, and the loading amounts of MnO2, Fe2O3, and V2O5 are 1.0 wt.%, 0.5 wt.%, and 2.0 wt.%, respectively.

[0121] The impregnation loading can optionally involve placing the dried catalyst in active liquid A, ultrasonically impregnating it for 15 min, removing it, and drying it at 120°C; or placing the catalyst in active liquid B, ultrasonically impregnating it for 15 min, removing it, and drying it at 120°C, optionally repeating this process 3 times. The calcination involves treating the catalyst impregnated with the active component at 340°C for 30 min.

[0122] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, with the original operating temperature reduced by 40°C while using the original volumetric design. The original operating temperature is the denitrification temperature designed for use before the deactivated denitrification catalyst is regenerated.

[0123] Implementation Case 15

[0124] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: dust removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The dust removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 160 kPa and the positive pressure is 0.4 MPa.

[0125] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 50°C for 45 min (NaOH concentration: 2.0 wt.%) and polyoxyethylene fatty alcohol ether concentration: 1.0 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 40°C for 60 min (H2SO4 concentration: 2.0 wt.%) and fatty acid amide concentration: 1.0 wt.%); and rinsing once with deionized water. The cleaned denitrification catalyst was then dried at 100°C with forced air until the moisture content was ≤6 wt.%.

[0126] The active solution was prepared by using compound V at 75°C to prepare active solution B; the concentration of V ions in active solution B was 2 wt.%, and the molar ratio of monoethanolamine to compound V was 1:0.8; the vanadium compound was NH4VO3.

[0127] The determined load amount is based on the operating temperature after regeneration, which is the amount of V2O5 loaded. The target operating temperature is 290℃, and the V2O5 load amount is 2.0 wt.%.

[0128] The impregnation loading involves placing the dried catalyst in active liquid B, ultrasonically impregnating it for 15 minutes, removing it, and drying it at 110°C. Optionally, this process is repeated three times. The calcination involves treating the catalyst with the impregnated and loaded active components at 280°C for 60 minutes.

[0129] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, with the original operating temperature reduced by 60°C while using the original volumetric design. The original operating temperature is the denitrification temperature designed for use before the deactivated denitrification catalyst is regenerated.

[0130] Implementation Case 16

[0131] A method for low-temperature modification and regeneration of a deactivated denitration catalyst includes the following steps: ash removal, cleaning, drying, preparation of an active liquid, determination of loading, impregnation loading, calcination, and design for use. The ash removal involves alternating negative pressure suction and positive pressure purging to remove surface and pore dust until the porosity reaches 99.0% or higher; the negative pressure is 130 kPa and the positive pressure is 0.4 MPa.

[0132] The cleaning process involved sequential ultrasonic-assisted bubbling cleaning with alkaline solution, acid solution, and water; cleaning with a mixture of NaOH and polyoxyethylene fatty alcohol ether at 50°C for 45 min (NaOH concentration: 2.0 wt.%) and polyoxyethylene fatty alcohol ether concentration: 1.0 wt.%); cleaning with a mixture of H2SO4 and fatty acid amide at 40°C for 60 min (H2SO4 concentration: 2.0 wt.%) and fatty acid amide concentration: 1.0 wt.%); and rinsing once with deionized water. The cleaned denitrification catalyst was then dried at 90°C with forced air until the moisture content was ≤6 wt.%.

[0133] The active solution was prepared by using compound V at 75°C to prepare active solution B; the concentration of V ions in active solution B was 3 wt.%, and the molar ratio of monoethanolamine to compound V was 1:0.8; the vanadium compound was V2O5.

[0134] The determined load amount is based on the operating temperature after regeneration, which is the amount of V2O5 loaded. The target operating temperature is 300℃, and the V2O5 load amount is 2.5 wt.%.

[0135] The impregnation loading involves placing the dried catalyst in active liquid B, ultrasonically impregnating it for 20 minutes, removing it, and drying it at 100°C. Optionally, this process can be repeated twice. The calcination involves treating the catalyst with the impregnated and loaded active components at 300°C for 60 minutes.

[0136] The design uses a volumetric design based on the operating temperature of the regenerated denitrification catalyst, with the original operating temperature reduced by 100°C and the volume used at 1.2 times the original volume. The original operating temperature is the designed denitrification temperature before the deactivated denitrification catalyst is regenerated.

Claims

1. A method for low-temperature modification and regeneration of a deactivated denitration catalyst, characterized in that, This includes steps such as ash removal, cleaning, drying, preparation of active liquid, determination of loading, impregnation loading, calcination, and design of usage. The dust removal process involves alternating between negative pressure suction and positive pressure blowing to remove dust from the surface and pores until the porosity reaches 99.0% or higher; the negative pressure is 20–500 kPa and the positive pressure is 0.2–1.0 MPa. The determination of the loading amount is based on the operating temperature after regeneration, which determines the amount of MnO2, Fe2O3, and V2O5 loaded. When the target operating temperature is 150–200°C, the loading amounts of MnO2, Fe2O3, and V2O5 are 0.5–2.0 wt.%, 0.2–1.5 wt.%, and 3.0–4.5 wt.%, respectively; when the target operating temperature is 200–250°C, the loading amounts of MnO2, Fe2O3, and V2O5 are 0–1.5 wt.%, 0–1.0 wt.%, and 2.5–3.0 wt.%, respectively; and when the target operating temperature is 250–300°C, the loading amounts of MnO2, Fe2O3, and V2O5 are 0–1.0 wt.%, 0–0.5 wt.%, and 2.0–2.5 wt.%, respectively. The calcination process involves treating the catalyst impregnated with the loaded active component at 280–420°C for 30–90 min. The design uses the volumetric amount based on the operating temperature of the regenerated denitrification catalyst. When the operating temperature is reduced by 0-60°C, the original volumetric amount is used; when the operating temperature is reduced by 60-120°C, 1.1-1.3 times the original volumetric amount is used; when the operating temperature is reduced by more than 120°C, 1.3-1.6 times the original volumetric amount is used. The original operating temperature is the designed denitrification temperature before the deactivated denitrification catalyst is regenerated.

2. The method for low-temperature modification and regeneration of a deactivated denitration catalyst according to claim 1, characterized in that, The cleaning process involves sequentially applying an alkaline solution, an acid solution, and water using ultrasonic-assisted bubbling. The alkaline cleaning uses a mixture of NaOH and polyoxyethylene fatty alcohol ether, applied at 40–50°C for 30–45 minutes, with NaOH concentrations of 2.0–8.0 wt.% and polyoxyethylene fatty alcohol ether concentrations of 0.5–2.0 wt.%. The acid cleaning uses a mixture of H₂SO₄ and fatty acid amide, applied at 40–60°C for 30–60 minutes, with H₂SO₄ concentrations of 1.0–6.0 wt.% and fatty acid amide concentrations of 0.5–2.0 wt.%. The water cleaning involves rinsing 1–3 times with deionized water.

3. The method for low-temperature modification and regeneration of a deactivated denitration catalyst according to claim 1, characterized in that, The drying process involves drying the cleaned denitrification catalyst by forced air at 60–120°C until the moisture content is ≤6 wt.%.

4. The method for low-temperature modification and regeneration of a deactivated denitration catalyst according to claim 1, characterized in that, The active solution is prepared by using Mn salt and Fe salt to prepare active solution A, and using compound V to prepare active solution B at 50-80℃; the concentration of Mn ions in active solution A is 1-5 wt.%, the concentration of Fe ions is 0-2.5 wt.%, and the concentration of polyoxyethylene fatty alcohol ether is 1-3 wt.%; the concentration of V ions in active solution B is 2-8 wt.%, and the molar ratio of monoethanolamine to compound V is 1:(0.8-1.2); the Mn salt is one or both of Mn(CH3COO)2 or Mn(NO3)2, the Fe salt is one or both of FeOH(CH3COO)2 or Fe(NO3)3, and the V compound is one or both of NH4VO3 and V2O5.

5. The method for low-temperature modification and regeneration of a deactivated denitration catalyst according to claim 1, characterized in that, The impregnation loading process involves placing the dried catalyst in active liquid A, ultrasonically impregnating it for 15–30 min, removing it, and drying it at 100–150 °C; then placing the catalyst in active liquid B, ultrasonically impregnating it for 15–30 min, removing it, and drying it at 100–150 °C. This process can be repeated 1–3 times.

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