SCR denitration deactivated catalyst deep pickling regeneration process

Abstract

The application relates to the technical field of flue gas denitration catalyst regeneration, and particularly discloses a deep pickling regeneration process for SCR denitration deactivated catalyst, which is characterized by comprising the following steps: S1, raw material pretreatment; S2, preliminary pickling; S3, reduction reaction; S4, chelation deep iron removal; S5, solid-liquid separation; S6, gradient water washing; and S7, drying treatment. The regenerated catalyst powder prepared by the process has excellent iron removal efficiency and denitration efficiency.

Description

Technical Field

[0001] This application relates to the field of flue gas denitrification catalyst regeneration technology, and more specifically, it relates to a deep acid washing regeneration process for SCR denitrification deactivated catalysts. Background Technology

[0002] SCR denitrification catalysts are the core materials of industrial flue gas denitrification systems. After long-term operation, they will become deactivated due to the deposition of fly ash and heavy metals (especially iron) in the flue gas. Iron accumulates on the catalyst surface and in the pores in various forms, including ferrous iron, ferric iron, and elemental iron, which leads to the covering of catalyst active sites and blockage of pores, resulting in a significant decrease in denitrification efficiency.

[0003] SCR catalyst regeneration methods include water washing, acid washing, SO2 acidification thermal regeneration, and thermal reduction regeneration, but acid washing is the most common. However, acid washing alone can only remove some soluble iron salts, and its removal effect on elemental iron and sparingly soluble iron oxides is poor, resulting in a low total iron removal rate. Consequently, the regenerated catalyst cannot meet feedstock-grade requirements. Therefore, a deep acid washing regeneration process for deactivated SCR denitrification catalysts is urgently needed. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a deep acid washing and regeneration process for SCR denitrification deactivated catalysts.

[0005] This application provides a deep acid washing and regeneration process for SCR denitration deactivated catalysts, which adopts the following technical solution: A deep acid washing and regeneration process for deactivated SCR denitration catalysts includes the following steps: S1. Raw material pretreatment: Grind the deactivated SCR denitrification catalyst to 200 mesh to obtain catalyst powder. Mix the catalyst powder with water, stir and heat to obtain a mixed slurry. S2. Preliminary pickling: Add sulfuric acid to the mixed slurry for preliminary pickling, keep warm and stir for 40-60 minutes to remove soluble iron salts and surface deposits, and obtain the pickled slurry; S3. Reduction reaction: Add a modified slow-release reducing agent to the pickled slurry, keep warm and stir for 20-40 minutes to reduce the ferric iron and elemental iron in the slurry to ferrous iron, and obtain the reduced slurry. S4. Iron removal by chelation depth: Oxalic acid is added to the reduced slurry to carry out the chelation reaction. The mixture is kept warm and stirred for 20-40 minutes to obtain the slurry after the reaction. S5. Solid-liquid separation: The reacted slurry is subjected to solid-liquid separation to obtain filtrate and mud cake respectively; S6. Step-by-step washing: The mud cake is subjected to step-by-step washing to reduce the content of acidic and soluble impurities, resulting in a washed mud cake. S7. Drying treatment: The washed mud cake is dried to obtain regenerated catalyst powder.

[0006] By employing the above technical solution, efficient, deep, and selective removal of iron from deactivated SCR denitrification catalysts is achieved. First, sulfuric acid is used for preliminary acid washing to dissolve and remove soluble iron salts and deposits on the surface, opening the pores. Then, a reducing agent is added to convert the difficult-to-dissolve trivalent iron and elemental iron into more readily reactant divalent iron, significantly improving subsequent iron removal efficiency. Next, the strong chelating effect of oxalic acid with divalent iron stably strips iron ions from the catalyst framework and transfers them to the liquid phase, achieving deep purification. Finally, a series of water washes remove residual acidic and soluble impurities. The entire process operates under mild reaction conditions, effectively protecting the active components (such as vanadium and tungsten) and support structure in the catalyst body while efficiently removing iron poisons, avoiding excessive corrosion. After this treatment, the pores of the regenerated catalyst are unblocked, active sites are re-exposed, and the denitrification activity can be significantly restored to near the level of a fresh catalyst. Furthermore, the process produces no harmful gas emissions, making it an environmentally friendly, economical, and efficient catalyst regeneration method.

[0007] Optionally, the preparation method of the modified sustained-release reducing agent includes the following steps: Sodium sulfite was dissolved in water, ascorbic acid was added to obtain a sodium sulfite solution, activated carbon was added to the sodium sulfite solution, the mixture was stirred and impregnated for 2-3 hours, filtered and dried to obtain a drug-loaded mesoporous carrier. Tween-80 was dissolved in ethanol to obtain an ethanol-coated solution. The drug-loaded mesoporous carrier was added to the ethanol-coated solution and stirred at 30-40°C for 1-2 hours. The temperature was then raised to 50-60°C, and the solution was distilled under reduced pressure and dried under vacuum to obtain the modified sustained-release reducing agent.

[0008] By adopting the above technical solutions, the strong antioxidant properties of ascorbic acid can effectively inhibit the air oxidation and degradation of sodium sulfite in solution. At the same time, the acidic microenvironment helps the subsequent dissolution of iron ions. The mesoporous structure of activated carbon achieves high-capacity loading of sodium sulfite reducing agent through capillary effect and spatial confinement. Its pore structure provides physical protection, slowing down the burst release and diffusion of the reducing agent. With the adsorption properties of activated carbon itself, the reducing agent is targeted and enriched around the iron deposits on the catalyst surface, forming a local high-concentration adsorption-reduction micro-reaction zone, which greatly improves the reaction efficiency. Finally, the hydrophobic coating of Tween-80 further constructs a slow-release barrier. In the dry storage state, this coating effectively isolates water vapor and oxygen in the air, significantly extending the shelf life of the reducing agent. After being added to the reaction system, the amphiphilic structure of Tween-80 can slowly detach or swell, allowing the internally loaded reducing agent to be released in a controllable manner, thus extending the action time and improving the stability of the reaction.

[0009] Optionally, the mass ratio of sodium sulfite, ascorbic acid, and activated carbon is 8-15:1:100.

[0010] By adopting the above technical solution and further limiting the mass ratio of sodium sulfite, ascorbic acid and activated carbon, a good sustained-release and stabilization effect can be achieved. Activated carbon, as a mesoporous carrier, provides the basis for adsorption and physical sustained release, while sodium sulfite, as a reducing agent, plays a major role. Ascorbic acid preferentially consumes oxygen and inhibits the oxidative failure of sodium sulfite during storage and drying.

[0011] Optionally, the mass ratio of Tween-80 to ethanol is 1:10-20; the mass ratio of the drug-loaded mesoporous carrier to the ethanol coating solution is 1:1.5-2.5.

[0012] Optionally, the heating temperature in the S1 raw material pretreatment is 50-80℃.

[0013] Optionally, the mass ratio of catalyst powder to water in the S1 raw material pretreatment is 1:1-3.

[0014] By adopting the above technical solution, the mass ratio of catalyst powder to water is controlled at 1:1-3, which achieves a good match between the slurry state and the requirements of subsequent processes. This ensures that the powder is fully wetted and the agglomerates are effectively dissociated, while avoiding the increase in subsequent drying energy consumption or loss of catalyst active components caused by excessive water volume.

[0015] Optionally, the concentration of sulfuric acid in S2 is 0.5-10 wt%.

[0016] Optionally, the drying temperature in the S7 drying process is 70-120℃.

[0017] In summary, this application has the following beneficial effects: 1. In this application, the synergistic effect of reduction, chelation, and slow release is used to achieve a high degree of removal of heavy metals from the deactivated SCR denitration catalyst. First, preliminary acid washing is used to dissolve surface iron salts and unclog pores. Then, a modified reducing agent is added to reduce the poorly soluble ferric iron to the more reactive ferrous iron. At the same time, the adsorption and enrichment of activated carbon and the slow-release barrier of the coating layer significantly improve the reduction stability and reaction efficiency. Subsequently, the strong chelation effect of oxalic acid and ferrous iron is used to stably strip iron ions from the catalyst framework to the liquid phase, achieving deep purification. Finally, after step-by-step water washing and drying, the pores of the regenerated catalyst are unclogged and the denitration activity is restored.

[0018] 2. In this application, a multi-layer structure design is used to achieve a synergistic improvement in reduction performance and stability. The addition of ascorbic acid can effectively inhibit the air oxidation failure of sodium sulfite in the solution, while creating an acidic microenvironment to promote the dissolution of iron ions. Secondly, the mesoporous structure of activated carbon, with the help of capillary effect and spatial confinement, not only achieves high capacity loading of reducing agent, but also slows down burst release and diffusion through physical encapsulation, and uses its adsorption performance to target and enrich the reducing agent around the iron deposits on the catalyst surface, forming a local high-concentration adsorption-reduction micro-reaction zone, which greatly improves the reaction efficiency. Detailed Implementation

[0019] The following embodiments provide a further detailed description of this application.

[0020] Preparation example of modified sustained-release reducing agent Raw material sources: Sodium sulfite with an effective substance content of 96%, industrial grade; activated carbon with an iodine value of 700-1000 mg / g and a specific surface area of ​​650-1200 m². 2 / g, ash content 5%.

[0021] Preparation Example 1-1: Dissolve 15g of sodium sulfite in 200g of deionized water, add 1g of ascorbic acid to obtain a sodium sulfite solution, add 100g of activated carbon to the sodium sulfite solution, stir and soak for 3h, filter, and dry at 60℃ for 12h to obtain a drug-loaded mesoporous carrier. 1g of Tween-80 was dissolved in 20g of anhydrous ethanol to obtain an ethanol-coated solution. 1g of drug-loaded mesoporous carrier was added to 2.5g of the ethanol-coated solution, stirred at 40℃ for 2h, heated to 60℃, and then distilled under reduced pressure and dried under vacuum to obtain the modified sustained-release reducing agent.

[0022] Preparation Example 1-2: Dissolve 10g of sodium sulfite in 200g of deionized water, add 1g of ascorbic acid to obtain a sodium sulfite solution, add 100g of activated carbon to the sodium sulfite solution, stir and impregnate for 2.5h, filter, and dry at 60℃ for 12h to obtain a drug-loaded mesoporous carrier. 1g of Tween-80 was dissolved in 15g of anhydrous ethanol to obtain an ethanol-coated solution. 1g of drug-loaded mesoporous carrier was added to 2g of the ethanol-coated solution. The mixture was stirred at 35℃ for 1.5h, heated to 55℃, and then distilled under reduced pressure and dried under vacuum to obtain the modified sustained-release reducing agent.

[0023] Preparation Examples 1-3: Dissolve 8g of sodium sulfite in 200g of deionized water, add 1g of ascorbic acid to obtain a sodium sulfite solution, add 100g of activated carbon to the sodium sulfite solution, stir and impregnate for 2h, filter, and dry at 60℃ for 12h to obtain a drug-loaded mesoporous carrier. 1g of Tween-80 was dissolved in 10g of anhydrous ethanol to obtain an ethanol-coated solution. 1g of drug-loaded mesoporous carrier was added to 1.5g of the ethanol-coated solution, stirred at 30℃ for 1h, heated to 50℃, and then distilled under reduced pressure and dried under vacuum to obtain the modified sustained-release reducing agent.

[0024] Preparation Example 1-4: The difference from Preparation Example 1-1 is that ascorbic acid was not added. 15g of sodium sulfite was dissolved in 200g of deionized water to obtain a sodium sulfite solution. 100g of activated carbon was added to the sodium sulfite solution, stirred and impregnated for 3h, filtered, and dried at 60℃ for 12h to obtain a drug-loaded mesoporous carrier. 1g of Tween-80 was dissolved in 20g of anhydrous ethanol to obtain an ethanol-coated solution. 1g of drug-loaded mesoporous carrier was added to 2.5g of the ethanol-coated solution, stirred at 40℃ for 2h, heated to 60℃, and then distilled under reduced pressure and dried under vacuum to obtain the modified sustained-release reducing agent.

[0025] Preparation Example 1-5: The difference from Preparation Example 1-1 is that activated carbon was not added. 15g of sodium sulfite was dissolved in 200g of deionized water, and 1g of ascorbic acid was added to obtain a sodium sulfite solution. The solution was dried at 60°C for 12h to obtain a mixed solid powder. 1g of Tween-80 was dissolved in 20g of anhydrous ethanol to obtain an ethanol-coated solution. 1g of mixed solid powder was added to 2.5g of the ethanol-coated solution, stirred at 40℃ for 2h, heated to 60℃, and then distilled under reduced pressure and dried under vacuum to obtain the modified slow-release reducing agent.

[0026] Preparation Example 1-6: The difference from Preparation Example 1-1 is that Tween-80 was not added. 15g of sodium sulfite was dissolved in 200g of deionized water, and 1g of ascorbic acid was added to obtain a sodium sulfite solution. 100g of activated carbon was added to the sodium sulfite solution, stirred and impregnated for 3h, filtered, and dried at 60℃ for 12h to obtain a drug-loaded mesoporous carrier. 1g of drug-loaded mesoporous carrier was added to 2.5g of anhydrous ethanol and stirred at 40℃ for 2h. The temperature was then raised to 60℃, and the mixture was distilled under reduced pressure and dried under vacuum to obtain the modified sustained-release reducing agent. Example

[0027] Example 1: A deep acid washing and regeneration process for SCR denitrification deactivated catalyst, comprising the following steps: S1. Raw material pretreatment: Grind the deactivated SCR denitrification catalyst to 200 mesh to obtain catalyst powder. Add 100 kg of catalyst powder and 300 kg of deionized water into the reactor, mix and stir and heat to 80°C to obtain a mixed slurry. S2. Preliminary pickling: Add 60 kg of 10 wt% sulfuric acid to the mixed slurry for preliminary pickling, keep warm and stir for 60 min to remove soluble iron salts and surface deposits, and obtain the pickled slurry. S3. Reduction reaction: Add 2 kg of the modified slow-release reducing agent prepared in Preparation Example 1-1 to the pickled slurry, keep warm and stir for 40 min to reduce the ferric iron and elemental iron in the slurry to ferrous iron, and obtain the reduced slurry. S4. Iron removal by chelation depth: Add 5 kg of oxalic acid to the reduced slurry to carry out the chelation reaction, keep warm and stir for 40 min to obtain the slurry after reaction; S5. Solid-liquid separation: The reacted slurry is fed into a filter press for solid-liquid separation to obtain filtrate and mud cake respectively. S6. Step-by-step washing: The mud cake is sent to a three-stage filter press system for step-by-step washing to reduce the content of acidic and soluble impurities, and obtain the washed mud cake. S7. Drying treatment: The washed mud cake is sent to a dryer and dried at 120°C to obtain regenerated catalyst powder.

[0028] Example 2: A deep acid washing and regeneration process for SCR denitrification deactivated catalyst, comprising the following steps: S1. Raw material pretreatment: Grind the deactivated SCR denitrification catalyst to 200 mesh to obtain catalyst powder. Add 100 kg of catalyst powder and 200 kg of deionized water into the reactor, mix and stir and heat to 60°C to obtain a mixed slurry. S2. Preliminary pickling: Add 50 kg of 8 wt% sulfuric acid to the mixed slurry for preliminary pickling, keep warm and stir for 50 min to remove soluble iron salts and surface deposits, and obtain the pickled slurry. S3. Reduction reaction: Add 1.5 kg of the modified slow-release reducing agent prepared in Preparation Example 1-2 to the pickled slurry, keep warm and stir for 30 min to reduce the ferric iron and elemental iron in the slurry to ferrous iron, and obtain the reduced slurry. S4. Iron removal by chelation depth: Add 4 kg of oxalic acid to the reduced slurry to carry out the chelation reaction, keep warm and stir for 30 min to obtain the slurry after reaction; S5. Solid-liquid separation: The reacted slurry is fed into a filter press for solid-liquid separation to obtain filtrate and mud cake respectively. S6. Step-by-step washing: The mud cake is sent to a three-stage filter press system for step-by-step washing to reduce the content of acidic and soluble impurities, and obtain the washed mud cake. S7. Drying treatment: The washed mud cake is sent to a dryer and dried at 100°C to obtain regenerated catalyst powder.

[0029] Example 3: A deep acid washing and regeneration process for SCR denitration deactivated catalyst, comprising the following steps: S1. Raw material pretreatment: Grind the deactivated SCR denitrification catalyst to 200 mesh to obtain catalyst powder. Add 100 kg of catalyst powder and 100 kg of deionized water into the reactor, mix and stir and heat to 50°C to obtain a mixed slurry. S2. Preliminary pickling: Add 40 kg of 0.5 wt% sulfuric acid to the mixed slurry for preliminary pickling, keep warm and stir for 40 min to remove soluble iron salts and surface deposits, and obtain the pickled slurry. S3. Reduction reaction: Add 1 kg of the modified slow-release reducing agent prepared in Preparation Examples 1-3 to the pickled slurry, keep warm and stir for 20 min to reduce the ferric iron and elemental iron in the slurry to ferrous iron, and obtain the reduced slurry. S4. Iron removal by chelation depth: Add 3 kg of oxalic acid to the reduced slurry to carry out the chelation reaction, keep warm and stir for 20 min to obtain the reacted slurry; S5. Solid-liquid separation: The reacted slurry is fed into a filter press for solid-liquid separation to obtain filtrate and mud cake respectively. S6. Step-by-step washing: The mud cake is sent to a three-stage filter press system for step-by-step washing to reduce the content of acidic and soluble impurities, and obtain the washed mud cake. S7. Drying treatment: The washed mud cake is sent to a dryer and dried at 70°C to obtain regenerated catalyst powder.

[0030] Example 4: A deep acid washing and regeneration process for SCR denitrification deactivated catalyst, comprising the following steps: S1. Raw material pretreatment: Grind the deactivated SCR denitrification catalyst to 200 mesh to obtain catalyst powder. Add 100 kg of catalyst powder and 50 kg of deionized water into the reactor, mix and stir and heat to 80°C to obtain a mixed slurry. S2. Preliminary pickling: Add 60 kg of 10 wt% sulfuric acid to the mixed slurry for preliminary pickling, keep warm and stir for 60 min to remove soluble iron salts and surface deposits, and obtain the pickled slurry. S3. Reduction reaction: Add 2 kg of the modified slow-release reducing agent prepared in Preparation Example 1-1 to the pickled slurry, keep warm and stir for 40 min to reduce the ferric iron and elemental iron in the slurry to ferrous iron, and obtain the reduced slurry. S4. Iron removal by chelation depth: Add 5 kg of oxalic acid to the reduced slurry to carry out the chelation reaction, keep warm and stir for 40 min to obtain the slurry after reaction; S5. Solid-liquid separation: The reacted slurry is fed into a filter press for solid-liquid separation to obtain filtrate and mud cake respectively. S6. Step-by-step washing: The mud cake is sent to a three-stage filter press system for step-by-step washing to reduce the content of acidic and soluble impurities, and obtain the washed mud cake. S7. Drying treatment: The washed mud cake is sent to a dryer to dry, and the regenerated catalyst powder is obtained.

[0031] Example 5: A deep acid washing and regeneration process for SCR denitration deactivated catalyst, comprising the following steps: S1. Raw material pretreatment: Grind the deactivated SCR denitrification catalyst to 200 mesh to obtain catalyst powder. Add 100 kg of catalyst powder and 300 kg of deionized water into the reactor, mix and stir and heat to 40°C to obtain a mixed slurry. S2. Preliminary pickling: Add 60 kg of 10 wt% sulfuric acid to the mixed slurry for preliminary pickling, keep warm and stir for 60 min to remove soluble iron salts and surface deposits, and obtain the pickled slurry. S3. Reduction reaction: Add 2 kg of the reducing agent prepared in Example 1-1 to the pickled slurry, keep warm and stir for 40 min to reduce the ferric iron and elemental iron in the slurry to ferrous iron, and obtain the reduced slurry. S4. Iron removal by chelation depth: Add 5 kg of oxalic acid to the reduced slurry to carry out the chelation reaction, keep warm and stir for 40 min to obtain the slurry after reaction; S5. Solid-liquid separation: The reacted slurry is fed into a filter press for solid-liquid separation to obtain filtrate and mud cake respectively. S6. Step-by-step washing: The mud cake is sent to a three-stage filter press system for step-by-step washing to reduce the content of acidic and soluble impurities, and obtain the washed mud cake. S7. Drying treatment: The washed mud cake is sent to a dryer to dry, and the regenerated catalyst powder is obtained.

[0032] Example 6: A deep acid washing and regeneration process for SCR denitrification deactivated catalyst, which differs from Example 1 in that the modified slow-release reducing agent is prepared by Examples 1-4.

[0033] Example 7: A deep acid washing and regeneration process for SCR denitrification deactivated catalyst, which differs from Example 1 in that the modified slow-release reducing agent is prepared by Example 1-5.

[0034] Example 8: A deep acid washing and regeneration process for SCR denitrification deactivated catalyst, which differs from Example 1 in that the modified slow-release reducing agent is prepared by Examples 1-6.

[0035] Comparative Example Comparative Example 1: A deep acid washing and regeneration process for SCR denitrification deactivated catalyst, which differs from Example 1 in that sodium sulfite is used to replace the modified slow-release reducing agent in an equal amount.

[0036] Performance testing Five grams of the regenerated catalyst powder prepared in Examples 1-8 and Comparative Example 1 were weighed, pressed into tablets, and then subjected to XRF analysis. The iron content in the regenerated catalyst powder is shown in Table 1; and the denitrification efficiency of the regenerated catalyst powder was tested.

[0037] Table 1 shows the iron content (measured as Fe2O3) and denitrification efficiency of the regenerated catalyst powders prepared in the examples and comparative examples.

[0038] Example 1 92 93 Example 2 108 91 Example 3 117 88 Example 4 124 87 Example 5 149 84 Example 6 172 82 Example 7 249 77 Example 8 193 80 Comparative Example 1 642 71 As can be seen from Examples 1-4 and Table 1, the regenerated catalyst powder prepared in this application has excellent regeneration effect.

[0039] Combining Examples 1 and 6 with Table 1, it can be seen that, compared with Example 1, the iron content of the regenerated catalyst powder prepared in Example 6 is increased and the catalyst denitrification efficiency is reduced. This indicates that sodium sulfite is easily oxidized and deactivated by air during the impregnation reaction. The addition of ascorbic acid will reduce the consumption of reducing components and improve the iron removal effect.

[0040] Combining Examples 1 and 7 with Table 1, it can be seen that, compared with Example 1, the iron content of the regenerated catalyst powder prepared in Example 7 is increased and the denitrification efficiency of the catalyst is reduced. This indicates that activated carbon provides a slow-release carrier, thereby improving the utilization rate of sodium sulfite and improving the iron removal effect and denitrification efficiency of the regenerated catalyst powder.

[0041] Combining Examples 1 and 8 with Table 1, it can be seen that, compared to Example 1, the iron content of the regenerated catalyst powder prepared in Example 8 is increased, and the catalyst denitrification efficiency is reduced. This indicates that Tween-80 can form a hydrophobic organic coating on the surface of activated carbon particles, preventing the instantaneous large-scale dissolution of sodium sulfite and its rapid failure, thus ensuring the continuous reduction of Fe during the regeneration process. 3+ .

[0042] Combining Example 1 and Comparative Example 1 with Table 1, it can be seen that, compared with Example 1, the iron content of the regenerated catalyst powder prepared in Comparative Example 1 is increased and the catalyst denitrification efficiency is reduced, indicating that the modified reducing agent can significantly improve the iron removal effect and enhance the denitrification efficiency.

[0043] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A deep acid washing and regeneration process for SCR denitrification deactivated catalyst, characterized in that, Includes the following steps: S1. Raw material pretreatment: Grind the deactivated SCR denitrification catalyst to 200 mesh to obtain catalyst powder. Mix the catalyst powder with water, stir and heat to obtain a mixed slurry. S2. Preliminary pickling: Add sulfuric acid to the mixed slurry for preliminary pickling, keep warm and stir for 40-60 minutes to remove soluble iron salts and surface deposits, and obtain the pickled slurry; S3. Reduction reaction: Add a modified slow-release reducing agent to the pickled slurry, keep warm and stir for 20-40 minutes to reduce the ferric iron and elemental iron in the slurry to ferrous iron, and obtain the reduced slurry. S4. Iron removal by chelation depth: Oxalic acid is added to the reduced slurry to carry out the chelation reaction. The mixture is kept warm and stirred for 20-40 minutes to obtain the slurry after the reaction. S5. Solid-liquid separation: The reacted slurry is subjected to solid-liquid separation to obtain filtrate and mud cake respectively; S6. Step-by-step washing: The mud cake is subjected to step-by-step washing to reduce the content of acidic and soluble impurities, resulting in a washed mud cake. S7. Drying treatment: The washed mud cake is dried to obtain regenerated catalyst powder.

2. The deep acid washing and regeneration process for the SCR denitrification deactivated catalyst according to claim 1, characterized in that, The preparation method of the modified sustained-release reducing agent includes the following steps: Sodium sulfite was dissolved in water, ascorbic acid was added to obtain a sodium sulfite solution, activated carbon was added to the sodium sulfite solution, the mixture was stirred and impregnated for 2-3 hours, filtered and dried to obtain a drug-loaded mesoporous carrier. Tween-80 was dissolved in ethanol to obtain an ethanol-coated solution. The drug-loaded mesoporous carrier was added to the ethanol-coated solution and stirred at 30-40°C for 1-2 hours. The temperature was then raised to 50-60°C, and the solution was distilled under reduced pressure and dried under vacuum to obtain the modified sustained-release reducing agent.

3. The deep acid washing and regeneration process for the SCR denitrification deactivated catalyst according to claim 2, characterized in that, The mass ratio of sodium sulfite, ascorbic acid and activated carbon is 8-15:1:

100.

4. The deep acid washing and regeneration process for the SCR denitrification deactivated catalyst according to claim 2, characterized in that, The mass ratio of Tween-80 to ethanol is 1:10-20; the mass ratio of the drug-loaded mesoporous carrier to the ethanol coating solution is 1:1.5-2.

5.

5. The deep acid washing and regeneration process for the SCR denitrification deactivated catalyst according to claim 1, characterized in that, The heating temperature in the pretreatment of raw material S1 is 50-80℃.

6. The deep acid washing and regeneration process for the SCR denitrification deactivated catalyst according to claim 1, characterized in that, In the S1 raw material pretreatment, the mass ratio of catalyst powder to water is 1:1-3.

7. The deep acid washing and regeneration process for the SCR denitrification deactivated catalyst according to claim 1, characterized in that, The concentration of sulfuric acid in the initial pickling (S2) is 0.5-10 wt%.

8. The deep acid washing and regeneration process for the SCR denitrification deactivated catalyst according to claim 1, characterized in that, The drying temperature in the S7 drying process is 70-120℃.