Method for cleaning and regenerating an scr denitration catalyst

Abstract

The application discloses a cleaning and regeneration method of an SCR denitration catalyst, and combines a softening heavy tar mode of oxygen-free low-temperature thermal melting, a low-frequency micro-ultrasonic and groove body bubble two-way stripping, a neutral biological base compound cleaning agent targeted tar dissolving, an active additive vanadium protection and a gradient rinsing whole-process coupling process, so that light and heavy composite tar and symbiotic alkali ash are removed step by step, and the whole process is low-temperature and non-calcination, the catalyst carrier crystal form and the denitration active component are protected, the cleaning efficiency is improved, and the catalyst integrity and environmental protection recyclability are improved.

Description

Technical Field

[0001] This invention relates to the field of flue gas denitrification catalyst regeneration and cleaning technology, and in particular to a cleaning and regeneration method for SCR denitrification catalysts. It is especially applicable to the green cleaning and regeneration process of vanadium-tungsten SCR denitrification catalysts that are blocked and deactivated by a combination of light volatile tar and polymerized solidified heavy tar under low-temperature flue gas conditions in coking plants, biomass gasification power plants, agricultural and forestry waste incineration, and coal chemical industries. Background Technology

[0002] The flue gas composition in coking, biomass gasification, and coal chemical industries is complex, containing a large amount of aromatic light tar and macromolecular polymerized heavy tar, while also carrying potassium, sodium, calcium, and alkaline metal dust. When the flue gas operates in the low-temperature range of 180-280℃, the tar easily adheres to the outer surface of the SCR denitrification catalyst and penetrates into the micron-sized pores of the catalyst. After long-term operation, the light tar in the micropores undergoes thermal polymerization, dehydrogenation, and carbonization, forming heavy tar scale with extremely high hardness and strong adhesion. This scale directly blocks the catalyst reaction micropores and coats the V2O5 denitrification active sites on the surface, significantly reducing the catalyst denitrification efficiency. This is the core cause of abnormal catalyst deactivation in the industrial denitrification field. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0004] A method for cleaning and regenerating an SCR denitrification catalyst is provided, the steps of which include:

[0005] S1. Pretreatment: The SCR denitrification catalyst is pretreated by a one-blowing and two-absorption cyclic coupling dry method to remove free floating ash and surface semi-solidified light tar from the SCR denitrification catalyst.

[0006] S2, low-temperature heat melting without oxygen: The pretreated SCR denitrification catalyst is placed in the chamber of the heat treatment equipment and heated to 55-62°C in a nitrogen atmosphere, and kept at a constant temperature for 40-60 minutes.

[0007] S3. Preparation of Cleaning Solution: The components and mass percentages of the cleaning solution include: 22-30% bio-based alcohol ether compound solvent, 3.5-6% nonionic emulsifying dispersant, 2-4% polycarboxylic acid chelating agent, 0.8-1.5% vanadium-tungsten active protective agent, and the remainder as dispersion medium; among which, the bio-based alcohol ether compound solvent includes diethylene glycol butyl ether and plant-based propylene glycol methyl ether; the nonionic emulsifying dispersant includes fatty alcohol polyoxyethylene ether and alkyl glycoside; the polycarboxylic acid chelating agent includes citric acid and sodium gluconate;

[0008] S4. Micro-ultrasonic and bubbling coupled cleaning: Immerse the SCR denitrification catalyst in the cleaning solution and perform ultrasonic and bubbling cleaning on the catalyst.

[0009] S5. Three-stage rinsing and gradient drying: The catalyst is cleaned of reagent impurities by three rinsings, and then dried at a low temperature in a gradient.

[0010] In a preferred embodiment of the present invention, the specific steps of the pretreatment in step S1 include: placing the SCR denitrification catalyst into a sealed dust removal chamber, and using a sealed negative pressure dust collection and high temperature drying compressed air bidirectional purging coupling process to pretreat the SCR denitrification catalyst.

[0011] In a preferred embodiment of the present invention, hot air purging: dry, oil-free compressed hot air at 45-55°C and 0.5-0.7 MPa is used to purge the honeycomb end face and sides of the SCR denitrification catalyst; negative pressure dust collection: during the purging process, the negative pressure generating equipment in the sealed dust collection chamber works synchronously, so that the sealed dust collection chamber maintains a negative pressure of 210-240 mbar.

[0012] In a preferred embodiment of the present invention, the diethylene glycol butyl ether and plant-based propylene glycol methyl ether in the bio-based alcohol ether compound solvent are mixed at a mass ratio of 2:1.

[0013] In a preferred embodiment of the present invention, the fatty alcohol polyoxyethylene ether and alkyl glycoside in the nonionic emulsifying dispersant are mixed at a mass ratio of 1.2:1.

[0014] In a preferred embodiment of the present invention, citric acid and sodium gluconate in the polycarboxylic acid chelating agent are mixed in a mass ratio of 1:1.

[0015] In a preferred embodiment of the present invention, in step S3, the vanadium-tungsten active protective agent is an aqueous anatase nano-titanium dioxide sol, an acidic neutral silica sol, or a zirconium sol.

[0016] In a preferred embodiment of the present invention, in step S3, the dispersion medium is deionized water.

[0017] In a preferred embodiment of the present invention, step S5 includes the following specific steps for the three-stage rinsing:

[0018] (1) First stage rinsing: The catalyst is placed in the recycled wastewater after the second stage rinsing, heated to 30-40°C, and rinsed using static and slight bubbling methods to recover the tar-containing organic waste liquid;

[0019] (2) Second stage rinsing: The catalyst is placed in the clean wastewater after the third stage fine rinsing and heated to 30-40°C for bubbling rinsing;

[0020] (2) Third stage rinsing: Put the catalyst into constant temperature deionized pure water, heat it to 30-40℃, and perform dynamic rinsing by bubbling.

[0021] In a preferred embodiment of the present invention, step S5, the specific steps of gradient drying under a protective atmosphere, include:

[0022] (1) First stage of low temperature pre-drying: The rinsed catalyst is placed in a drying oven with a nitrogen atmosphere of slight positive pressure and gas internal circulation. The temperature is raised to 45°C and dried at a constant temperature for 30 min to remove free water from the catalyst surface.

[0023] (2) Second stage of medium temperature deep drying: the temperature is increased from 45℃ to 75℃ at a rate of ≤1.5℃ / min. When the temperature reaches 75℃, the temperature is kept constant for 70 min to remove the microporous adsorbed bound water.

[0024] The beneficial effects of this invention are: it combines a low-temperature, oxygen-free thermal melting method to soften heavy tar, low-frequency micro-ultrasound combined with tank bubbling for bidirectional stripping, neutral bio-based compound cleaning agent for targeted tar dissolution, active additives for vanadium protection, and a gradient rinsing process to achieve stepwise removal of light and heavy composite tar and symbiotic alkaline ash, all at low temperatures without calcination, protecting the catalyst carrier crystal form and denitrification active components. This not only improves cleaning efficiency but also enhances catalyst integrity and environmental reusability. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The embodiments of the present invention include:

[0027] A method for cleaning and regenerating an SCR denitrification catalyst, comprising the following steps:

[0028] S1. Pretreatment: The SCR denitrification catalyst is pretreated by a one-blowing and two-absorption cyclic coupling dry method to remove free floating ash and semi-solidified light tar on the SCR denitrification catalyst, so as to avoid solid ash carrying tar and embedding it into the micropores and reduce the subsequent cleaning load.

[0029] Furthermore, the SCR denitrification catalyst is placed in a sealed dust collection chamber, and a sealed negative pressure dust collection + high temperature drying compressed air bidirectional purging coupling process is used to pretreat the SCR denitrification catalyst.

[0030] S1.1 Hot air purging: Use dry, oil-free compressed hot air at 45-55℃ and a pressure of 0.5-0.7MPa. Use a multi-hole matrix purging nozzle to target the honeycomb end face and sides of the SCR denitrification catalyst, fully covering the honeycomb channels, catalyst sides, and ribs to remove tar dust adhering to them, and thoroughly remove free contaminants from the surface of the SCR denitrification catalyst.

[0031] When the honeycomb end face of the catalyst is purged in the forward direction, a high-pressure airflow enters the catalyst channels, blowing off the surface dust and loose dust in the shallow layer of the channels. At the same time, the hot air softens the semi-solidified, low-temperature flowable light tar on the catalyst surface (the boiling point of tar is in the range of 200-350℃; at 45-55℃, the viscosity of the surface light tar decreases significantly, losing its adhesiveness), and is carried away and peeled off by the airflow. The purging of the sides of the catalyst is carried out in the same way.

[0032] Furthermore, a three-dimensional blowing mode of "front blowing → flipping blowing → end face lateral blowing" is adopted for cyclic blowing.

[0033] S1.2 Synchronous negative pressure dust collection: During the purging process in step 1.1), the negative pressure generating equipment (such as vacuum pump, negative pressure fan, etc.) in the sealed dust collection chamber continues to work, so that the sealed dust collection chamber maintains a negative pressure of 210-240 mbar. The blown-off dust, liquid light tar droplets, and tar ash mixture are immediately sucked out by the negative pressure, avoiding the dust and tar from falling back and adhering to the catalyst micropores.

[0034] Furthermore, the production equipment is connected to a dust collector bag and an oil-gas condensation recovery device, so that the waste material sucked out by the dust collector bag is collected and sent to the oil-gas condensation recovery device, and the oil-gas condensation recovery device separates the fertilizer into oil and gas.

[0035] Furthermore, the total time for a single blow-and-vacuum cycle is 25–40 minutes.

[0036] S2. Oxygen-free low-temperature heat fusion: The pretreated SCR denitrification catalyst is placed into the chamber of the heat treatment equipment, and high-purity nitrogen is continuously introduced into the chamber to replace the air (oxygen); the temperature inside the chamber is raised to 55-62℃, the heating rate is ≤2℃ / min, and the upper limit of the temperature must not exceed 62℃; the temperature is kept constant for 40-60 minutes.

[0037] Traditional high-temperature roasting decoking processes use 350-450℃ high-temperature air roasting to crack tar, which easily causes oxygen deficiency, carbonization, and coking of tar in micropores, resulting in secondary solidification and pore blockage. At the same time, high temperature will destroy the active crystal form of TiO2 anatase, causing high-temperature sintering and agglomeration of vanadium-tungsten active components, leading to irreversible deactivation of the catalyst.

[0038] This application uses low-temperature softening cross-linking polymerization of heavy tar, which reduces the adhesion between the tar and the TiO2 support interface, thereby separating the tar from the catalyst without affecting the catalyst's activity. It also eliminates secondary coking caused by high-temperature oxidation and carbonization, and does not require high-temperature pyrolysis.

[0039] The core configuration of the heat treatment equipment includes:

[0040] • Sealed, pressure-resistant, and insulated chamber (carbon steel anti-corrosion lining, explosion-proof design);

[0041] • Electric heating circulating temperature control system, continuous nitrogen replacement inlet, and online oxygen content detector in the chamber;

[0042] • Centralized collection of waste gas (trace amounts of tar volatiles) + activated carbon adsorption treatment device;

[0043] • Modular high-temperature resistant catalyst placement bracket and nitrogen circulation fan.

[0044] The heat treatment equipment can employ existing technologies in this field, and will not be described in detail here.

[0045] S3. Preparation of cleaning solution

[0046] The cleaning solution includes a bio-based alcohol ether compound solvent, a nonionic emulsifying dispersant, a polycarboxylic acid chelating agent, a vanadium-tungsten active protective agent, and a dispersion medium.

[0047] The compounded bio-based alcohol ether cleaning agent accounts for 22% to 30% of the total mass of the mixed solution, with a preferred addition amount of 26.00 wt%.

[0048] The amount of nonionic emulsifying dispersant added is 3.5wt% to 6wt% of the total mass of the cleaning solution, with a preferred amount of 4.5wt%.

[0049] The amount of polycarboxylic acid chelating agent added is 2.0 wt% to 4.0 wt% of the total mass of the cleaning solution;

[0050] The amount of vanadium-tungsten active protective additive added is 0.8% to 1.5% of the total mass of the cleaning solution, with a preferred addition amount of 1.2 wt%.

[0051] The rest are dispersion media.

[0052] For example, the composition and mass percentage of the cleaning solution include 26.00% bio-based alcohol ether compound solvent, 4.50% nonionic emulsifying dispersant, 3.00% polycarboxylic acid chelating agent, 1.20% vanadium tungsten active protective agent, and 65.30% dispersion medium.

[0053] Furthermore, the bio-based alcohol ether compound solvent includes diethylene glycol butyl ether and plant-based propylene glycol methyl ether mixed in a mass ratio of 2:1.

[0054] For example, the mass percentage of diethylene glycol butyl ether is 17.33 wt%, the mass percentage of plant-based propylene glycol methyl ether is 8.67 wt%, and the total mass percentage is 26 wt%.

[0055] Furthermore, the nonionic emulsifying dispersant includes fatty alcohol polyoxyethylene ether (nonionic surfactant) and alkyl glycoside (bio-based green nonionic emulsifier) ​​in a mass ratio of 1.2:1.

[0056] For example, the mass percentage of fatty alcohol polyoxyethylene ether is 2.45%, and the mass percentage of alkyl glycoside is 2.05%.

[0057] Furthermore, the polycarboxylic acid chelating agent includes citric acid and sodium gluconate, which is compatible with the system's chelating agent and does not introduce new impurities. The mass ratio of citric acid to sodium gluconate is 1:1.

[0058] For example, the mass percentage of citric acid is 1.50%, and the mass percentage of sodium gluconate is 1.50%.

[0059] In some instances of this application, the vanadium-tungsten active protective agent uses a 20nm aqueous anatase nano-titanium dioxide sol with a solid content of 15%. The vanadium-tungsten active protective agent comprises 20nm aqueous anatase nano-titanium dioxide, deionized water, and a dispersant stabilizer. The dispersant stabilizer is a trace amount of citric acid, which ensures compatibility with the system's chelating agent and avoids introducing new impurities.

[0060] In some instances of this application, the vanadium-tungsten active protective agent is silica sol (acidic neutral silica sol, particle size 10-30 nm), and the amount of silica sol added is 0.8%-1.5% of the total mass of the cleaning solution; the silica sol can fill the carrier defects and form a silicon dioxide passivation film on the TiO2 surface to inhibit the dissolution of vanadium components.

[0061] In some examples of this application, the vanadium-tungsten active protective agent is zirconium sol (nano-zirconia aqueous sol), and the amount of zirconium sol added is 0.8% to 1.5% of the total mass of the cleaning solution. Zirconium sol has stronger chemical stability, is resistant to acids and alkalis, and is suitable for catalysts with high impurities and severe poisoning.

[0062] Furthermore, deionized water is used as the dispersion medium.

[0063] The cleaning solution of this application is composed of a neutral emulsification-chelation-activation protection integrated system, which is formed by the synergistic action of a bio-based alcohol ether compound solvent, a nonionic emulsifying dispersant, an organic polycarboxylic acid chelating agent, and a vanadium-tungsten active protective agent. Each component is indispensable. The system is neutral throughout and contains no strong acids or bases.

[0064] Bio-based alcohol ether compound solvents, as functional components in the oil phase, rely on the principle of "like dissolves like" to target and dissolve light and heavy tar in the pores of the SCR denitrification catalyst, making them the core functional component for tar removal in the system.

[0065] Nonionic emulsifying dispersants are used to reduce the interfacial tension between oil and water, allowing alcohol ether solvents to be stably dispersed in water, and to emulsify and encapsulate the dissolved tar, preventing the desorbed tar from adhering to the micropore walls of the catalyst or from adsorbing and clogging the pores.

[0066] An active protection + chelation impurity removal system was constructed by using polycarboxylic acid chelating agents and vanadium-tungsten active protection additives. Titanium sol protective additives were added during the cleaning stage to provide active protection, which can passivate the lattice defect sites of the catalyst TiO2 support in situ, adsorb and lock the V2O5 active components, inhibit the dissolution of vanadium-tungsten active components, and further reduce the vanadium-tungsten loss rate.

[0067] Organic polycarboxylic acid chelating agents simultaneously complex and remove alkali metal ions such as K, Na, and Ca, and inhibit the hydrolysis and dissolution of vanadium and tungsten under neutral conditions.

[0068] S4. Micro-ultrasound + bubbling coupled cleaning: The SCR denitrification catalyst is immersed in the cleaning solution and then subjected to ultrasonic and bubbling cleaning. Low-frequency ultrasound can penetrate the micropores of the catalyst, achieving tar emulsification and stripping within the micropores, while bubbling in the tank enhances the flow and renewal of the cleaning solution.

[0069] This method is a green and low-pollution process, with no heavy metals added and no highly toxic agents. The amount of waste generated is far lower than that of traditional pickling and high-temperature roasting processes.

[0070] S5, Three-stage rinsing + gradient drying: Three rinsing stages are used to clean the reagent impurities attached to the catalyst. Then, gradient low-temperature drying is used to avoid thermal stress cracking and fully preserve the mechanical strength of the catalyst.

[0071] Conditions for three rinsing steps: water temperature is uniformly controlled at 30-40℃ (constant temperature), and it is strictly forbidden to exceed 40℃; bubbling volume is 0.15-0.25 m³ / min; conductivity is ≤50 μS / cm; and pH is maintained at 6.5-7.5.

[0072] S5.1 The specific steps of the three-stage rinsing include:

[0073] 5.1.1) First stage rinsing (coarse rinsing, high pollutant wastewater section)

[0074] a. Influent source: Reclaimed wastewater after the second-stage rinsing;

[0075] b. Target of treatment: Catalysts that have just been taken out of the ultrasonic tar cleaning tank, with a large amount of high-concentration alcohol ether solvents, emulsified tar, and suspended ash adhering to their surface;

[0076] c. Core function: to rapidly wash away high-concentration tar cleaning agents from the catalyst surface and recover tar-containing organic waste liquid;

[0077] d. Wastewater destination: Collected separately, after oil filtration and tar separation, the upper solvent can be reused in the S3 cleaning process, and the lower high-COD wastewater is sent to the biochemical system for treatment;

[0078] e. Water temperature: 30~40℃, static + light bubbling rinse.

[0079] 5.1.2) Second-stage rinsing (intermediate rinsing, cleaning agent purification stage)

[0080] a. Influent source: Clean wastewater after the third-stage fine rinsing;

[0081] b. Target of treatment: After primary coarse washing, the catalyst surface contains low concentrations of cleaning agent and trace amounts of emulsified tar;

[0082] c. Core function: Significantly reduces the concentration of residual reagents in the catalyst pores, preventing reagents from being carried into the final washing section and causing waste of pure water;

[0083] d. Wastewater destination: All wastewater is transported counter-currently to the primary rinsing tank for recycling, significantly reducing the consumption of fresh water.

[0084] 5.1.3) Third stage rinsing (fine rinsing, final rinse with pure water)

[0085] a. Inlet water: Fresh, constant-temperature deionized pure water (conductivity ≤10μS / cm);

[0086] b. Target of treatment: Catalyst after secondary rinsing, to remove trace amounts of residual chelating agents and surfactants from the micropores;

[0087] c. Core function: To ensure that there are no reagent residues on the surface and in the pores of the catalyst, and to prevent the high-temperature crystallization of reagents during the drying stage from clogging the micropores and covering the active sites;

[0088] d. Wastewater destination: Recycled by countercurrent flow into a secondary rinsing tank;

[0089] e. Process requirements: Dynamic bubbling rinsing to ensure sufficient replacement of the channels.

[0090] S5.2 The specific steps of gradient drying under nitrogen protective gas include:

[0091] 5.2.1) First stage: Low-temperature pre-drying stage (removal of free water from the catalyst surface)

[0092] Drying temperature: 45℃; constant temperature holding time: 30 min; atmosphere: nitrogen gas with slight positive pressure and closed system, gas internal circulation.

[0093] Core objective: To slowly remove free liquid water from the outer surface and large pores of the catalyst honeycomb, avoiding direct high temperature causing rapid vaporization of water and instantaneous expansion of water vapor, which would lead to thermal stress cracking of the catalyst ceramic matrix; and at the same time, to prevent the rapid volatilization and localized heat accumulation and carbonization of residual small amounts of alcohol ether solvent in the pores.

[0094] 5.2.2) Second stage: Medium-temperature deep drying stage (removal of microporous adsorbed bound water)

[0095] Drying temperature: 75℃; Constant temperature holding time: 70 min; Temperature control: from 45℃ to 75℃, the heating rate must be strictly ≤1.5℃ / min, and rapid heating is prohibited.

[0096] Core objective: To remove adsorbed bound water from the micron-sized pores of the catalyst, ensuring complete dryness of the catalyst pores and preventing residual moisture from causing hydrolysis and failure of the active components; the entire process is carried out at a temperature not exceeding 75℃, without high-temperature calcination, to protect the TiO2 anatase crystal form and avoid vanadium-tungsten sintering and agglomeration.

[0097] Direct drying at 75°C causes rapid vaporization of surface moisture, leading to a sudden increase in water vapor pressure within the pores. This can easily cause end-face cracking and rib breakage in the honeycomb ceramic. Simultaneously, residual trace amounts of cleaning agent crystallize upon heating, clogging the micropores. Therefore, this application employs a pre-drying process at 45°C to smoothly remove surface free water, gradually release moisture from the pores, and eliminate thermal stress. This is followed by deep drying at 75°C to thoroughly remove bound water from the micropores, balancing mechanical strength and drying effectiveness. Furthermore, a nitrogen atmosphere is maintained throughout the process to prevent trace amounts of residual tar and organic solvents from being oxidized and carbonized by oxygen, thus preventing pore blockage, and also to avoid oxidation and deactivation of the vanadium components on the catalyst surface.

[0098] The beneficial effects of the cleaning and regeneration method for SCR denitrification catalyst of this invention are as follows: It combines the softening of heavy tar by oxygen-free low-temperature thermal melting, bidirectional stripping by low-frequency micro-ultrasound and tank bubbling, targeted coke dissolution by neutral bio-based compound cleaning agent, vanadium protection by active additives, and gradient rinsing into a fully coupled process. This achieves the stepwise removal of light and heavy composite tar and symbiotic alkaline ash, with low temperature and no calcination throughout the process, protecting the crystal form of the catalyst support and the denitrification active components. This not only improves the cleaning efficiency but also enhances the integrity of the catalyst and its environmental reusability.

[0099] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for cleaning and regenerating an SCR denitrification catalyst, characterized in that the steps include... include: S1. Pretreatment: The SCR denitrification catalyst is pretreated by a one-blowing and two-absorption cyclic coupling dry method to remove free floating ash and surface semi-solidified light tar from the SCR denitrification catalyst. S2, low-temperature heat melting without oxygen: The pretreated SCR denitrification catalyst is placed in the chamber of the heat treatment equipment and heated to 55-62°C in a nitrogen atmosphere, and kept at a constant temperature for 40-60 minutes. S3. Preparation of Cleaning Solution: The components and mass percentages of the cleaning solution include: 22-30% bio-based alcohol ether compound solvent, 3.5-6% nonionic emulsifying dispersant, 2-4% polycarboxylic acid chelating agent, 0.8-1.5% vanadium-tungsten active protective agent, and the remainder as dispersion medium; among which, the bio-based alcohol ether compound solvent includes diethylene glycol butyl ether and plant-based propylene glycol methyl ether; the nonionic emulsifying dispersant includes fatty alcohol polyoxyethylene ether and alkyl glycoside; the polycarboxylic acid chelating agent includes citric acid and sodium gluconate; S4. Micro-ultrasonic and bubbling coupled cleaning: Immerse the SCR denitrification catalyst in the cleaning solution and perform ultrasonic and bubbling cleaning on the catalyst. S5. Three-stage rinsing and gradient drying: The catalyst is cleaned of reagent impurities by three rinsings, and then dried at a low temperature in a gradient.

2. The method for cleaning and regenerating an SCR denitrification catalyst according to claim 1, characterized in that, In step S1, the specific steps of pretreatment include: placing the SCR denitrification catalyst into a sealed dust removal chamber, and using a sealed negative pressure dust collection and high-temperature drying compressed air bidirectional purging coupling process to pretreat the SCR denitrification catalyst.

3. The method for cleaning and regenerating an SCR denitrification catalyst according to claim 2, characterized in that, Hot air purging: Dry, oil-free compressed hot air at 45-55℃ and 0.5-0.7MPa is used to purge the honeycomb end face and sides of the SCR denitrification catalyst; Negative pressure dust collection: During the purging process, the negative pressure generating equipment in the sealed dust collection chamber works synchronously to maintain a negative pressure of 210-240mbar in the sealed dust collection chamber.

4. The method for cleaning and regenerating an SCR denitrification catalyst according to claim 1, characterized in that, The diethylene glycol butyl ether and plant-based propylene glycol methyl ether in the bio-based alcohol ether compound solvent are mixed at a mass ratio of 2:

1.

5. The method for cleaning and regenerating an SCR denitrification catalyst according to claim 1, characterized in that, The nonionic emulsifying dispersant contains fatty alcohol polyoxyethylene ether and alkyl glycoside mixed at a mass ratio of 1.2:

1.

6. The method for cleaning and regenerating an SCR denitrification catalyst according to claim 1, characterized in that, The citric acid and sodium gluconate in the polycarboxylic acid chelating agent are mixed in a mass ratio of 1:

1.

7. The method for cleaning and regenerating an SCR denitrification catalyst according to claim 1, characterized in that, In step S3, the vanadium-tungsten active protective agent is an aqueous anatase nano-titanium dioxide sol, acidic neutral silica sol, or zirconium sol.

8. The method for cleaning and regenerating an SCR denitrification catalyst according to claim 1, characterized in that, In step S3, the dispersion medium is deionized water.

9. The method for cleaning and regenerating an SCR denitrification catalyst according to claim 1, characterized in that, In step S5, the specific steps of the three-stage rinsing include: (1) First stage rinsing: The catalyst is placed in the recycled wastewater after the second stage rinsing, heated to 30-40°C, and rinsed using static and slight bubbling methods to recover the tar-containing organic waste liquid; (2) Second stage rinsing: The catalyst is placed in the clean wastewater after the third stage fine rinsing and heated to 30-40°C for bubbling rinsing; (2) Third stage rinsing: Put the catalyst into constant temperature deionized pure water, heat it to 30-40℃, and perform dynamic rinsing by bubbling.

10. The method for cleaning and regenerating an SCR denitrification catalyst according to claim 1, characterized in that, In step S5, the specific steps of gradient drying under a protective atmosphere include: (1) First stage of low temperature pre-drying: The rinsed catalyst is placed in a drying oven with a nitrogen atmosphere of slight positive pressure and gas internal circulation. The temperature is raised to 45°C and dried at a constant temperature for 30 min to remove free water from the catalyst surface. (2) Second stage of medium temperature deep drying: the temperature is increased from 45℃ to 75℃ at a rate of ≤1.5℃ / min. When the temperature reaches 75℃, the temperature is kept constant for 70 min to remove the microporous adsorbed bound water.