A method for regenerating an arsenic-poisoned SCR denitrification catalyst
Through advanced oxidation technology, the problem of SCR denitrification catalyst inactivation due to arsenic poisoning is solved, and efficient arsenic compound removal and catalyst regeneration are achieved, which extends the catalyst life and reduces the wastewater treatment cost.
Patent Information
- Application Number
- CN202310566576.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-05-19
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2043-05-19
AI Technical Summary
In the prior art, SCR denitrification catalysts are prone to inactivate due to arsenic poisoning during use, and the existing regeneration methods have problems such as mechanical strength damage, high wastewater treatment cost and secondary poisoning, which is difficult to effectively reduce the amount of arsenic residue, affecting the catalyst. regeneration effect.
Adopting advanced oxidation process coupled with weak alkali washing method, the SCR denitrification catalyst is regenerated and treated, and the ozone and oxygen reaction in weak alkaline solution are produced by the reaction of HO2- and active O atoms, arsenic compounds are oxidized and the active components of the catalyst are adjusted, combined with mechanical blowing. Ash and calcination steps to achieve the regeneration of the catalyst.
It significantly improves the arsenic removal rate and activity of the catalyst, extends the service life of the catalyst, reduces the vanadium supplementation demand during the regeneration process, avoids secondary poisoning, and reduces the cost of wastewater treatment.
Smart Images
Figure CN116603575B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of environmental protection technology and denitration catalysis, and particularly relates to a regeneration method for an arsenic-poisoned SCR denitration catalyst.
[0002] Background Methods
[0003] V 2 O 5 -WO 3 / TiO 2 The selective catalytic reaction (SCR) denitrification catalyst is widely used in industrial production tail gas NOx control, with NH 3 As a reducing agent, SCR selectively converts NOx pollutants into N 2 and H 2 O. Due to the high prices of the three valuable metals V, W, and Ti, V 2 O 5 -WO 3 / TiO 2 The price of the catalyst is very expensive, accounting for 30%-50% of the total cost of the air pollution control system. In addition, due to various reasons such as sintering, clogging, poisoning, wear, breakage or changes in its morphology, the SCR catalyst will be deactivated during use. In particular, the extremely complex components in the flue gas from coal combustion accelerate the deactivation of the SCR catalyst by adsorbing or removing alkali, alkaline earth, metalloids and heavy metals (such as K, Na, Ca, Mg, As, Hg). The service life of the SCR catalyst is an average of 3 to 5 years. Due to my country's extremely high coal consumption of more than 3.5 billion tons per year and the ultra-low emission standard of flue gas (NOx is 50 mg / m3), my country currently uses about 1 million tons of SCR catalysts, resulting in an annual production of 300,000 tons of waste SCR catalysts. The waste SCR catalyst contains a variety of valuable metals such as V, W, Ti, etc. Therefore, the resource utilization of waste SCR catalysts is of great significance.
[0004] However, due to the presence of toxic elements such as As, Hg, and Pb in the spent SCR catalyst, it is identified as hazardous waste. Improper treatment will cause serious environmental pollution and human harm. Among them, the high arsenic content in the raw coal (average dose of 3.79 mg / kg) makes the toxic element As, as As 2 O 3 and As 2 O 5 As is deposited and accumulated in large quantities on the catalyst surface and in the catalyst channels. 3+ and As 5+ At the same time, it is adsorbed on the active center (mainly V 2 O 5 ) and inactive centers (TiO 2 carrier), resulting in the replacement of V-OH by As-OH, thereby inhibiting the NH 3Adsorption on the Lewis acid centers of the catalyst eventually leads to catalyst deactivation and inability to convert NOx pollutants into N 2 and H 2 O. Due to V 2 O 5 The amount used in industrial catalysts is very small, and even a small amount of As can have a serious impact on the performance of the catalyst. Therefore, arsenic poisoning is considered to be the most common and serious cause of SCR catalyst deactivation. In order to ensure that the activity of remanufactured catalysts is not reduced, the Ministry of Science and Technology of China has proposed an initiative for "solid waste recycling", requiring that the arsenic residue in SCR catalyst regeneration products should be less than 200 mg / kg. At present, the industrial standard for the waste catalyst recycling industry is that the arsenic content of waste slag is 200 mg / kg. Therefore, the regeneration of arsenic-rich waste SCR catalysts has important practical engineering significance.
[0005] At present, the regeneration of arsenic-poisoned SCR catalysts is carried out by removing arsenic elements through water washing, alkali leaching or acid leaching in production. Among them, water washing can remove a part of alkali metals, but has little effect on the removal of arsenic. The deactivated SCR denitrification catalyst treated with strong acid will cause the mechanical strength of the regenerated catalyst to be damaged, reducing the service life of the SCR denitrification catalyst. When sodium salt or potassium salt is used to clean the As-poisoned catalyst, the cleaning liquid introduces new toxic components - sodium ions and potassium ions - to the catalyst surface, resulting in a large amount of waste liquid in the subsequent cleaning work, thereby increasing the cost of wastewater treatment.
[0006] In addition, there are technical solutions in the prior art that use strong oxidants such as potassium permanganate, sodium hypochlorite, and hydrogen peroxide to treat arsenic-poisoned SCR denitrification catalysts, which can convert As 2 O 3 Oxidized to As 2 O 5 ; However, potassium permanganate and sodium hypochlorite will introduce a large amount of alkali metal ion impurities during the oxidation process, leading to secondary poisoning; and the price of hydrogen peroxide is slightly high, which is not suitable for large-scale use in industrial production processes. Summary of the invention
[0007] The object of the present invention is to provide a method for regenerating an arsenic-poisoned SCR denitration catalyst which is simple in process, economical and efficient.
[0008] A method for regenerating an arsenic-poisoned SCR denitration catalyst comprises the following steps:
[0009] Step 1: mechanically blow off the regenerated SCR denitration catalyst, crush it, grind it and sieve it to obtain catalyst powder.
[0010] Step 2: Place the catalyst powder obtained in step 1 in an alkaline solution for soaking and cleaning; and introduce a mixed gas of ozone, oxygen and nitrogen into the alkaline solution for stirring and reaction. The alkaline solution is a weak alkaline solution with a pH value of 9.0 to 13.0.
[0011] Step 3: Wash and dry the solid product obtained in step 2.
[0012] Step 4: Immerse the solid product obtained in step 3 in the regeneration liquid.
[0013] Step 5: calcine the solid product obtained in step 4 to obtain a regenerated SCR denitration catalyst. During the calcination process, the precursor on the surface of the SCR denitration catalyst is converted into an active component.
[0014] Preferably, before the crushing, grinding and screening in step 1, the regenerated SCR denitration catalyst is purged and deashed.
[0015] Preferably, the regenerated SCR denitration catalyst is a vanadium-tungsten-titanium system denitration catalyst. The regeneration liquid in step 4 contains one or more of ammonium metavanadate, ammonium metatungstate and ammonium heptamolybdate, and the immersion time is 0.5h to 3.0h.
[0016] Preferably, the mass concentration of ammonium metavanadate, ammonium metatungstate and ammonium heptamolybdate in the regeneration solution is 0.1wt% to 2.0wt%.
[0017] Preferably, the regenerated SCR denitration catalyst is a honeycomb or flat plate catalyst.
[0018] Preferably, the particle size of the catalyst powder obtained in step 1 is 200-300 meshes.
[0019] Preferably, the concentration of ozone in the mixed gas of ozone, oxygen and nitrogen in step 2 is 1 mg / L to 50 mg / L.
[0020] Preferably, the alkaline solution in step 2 is a mixture of one or more alkaline solutions selected from ammonia water, ammonium bicarbonate solution and monoethanolamine solution, and the solution concentration is 0.1 to 5.0 mol / L, and the cleaning time is 10 to 240 min. Using monoethanolamine, ammonia water and ammonium bicarbonate for cleaning can effectively avoid K + and Na + The introduction of alkali metal ions can avoid secondary poisoning.
[0021] Preferably, in step 3, the drying temperature is 80-130° C., and the drying time is 8-16 hours.
[0022] Preferably, in step 5, the calcination temperature is 450-600° C., the heating rate is 10-30° C. / min, and the calcination time is 2-12 h.
[0023] The present invention has the following beneficial effects:
[0024] 1. The present invention adopts an advanced oxidation process coupled with weak alkaline washing to regenerate the arsenic poisoned SCR denitrification catalyst; the O 3 In a weakly alkaline environment, - Ions react to generate HO 2 - With O 2 HO 2 - Hydrolysis generates ·OH and active O atoms, which can utilize the strong oxidizing properties of ·OH and active O atoms to remove most of the As on the surface of the arsenic-poisoned catalyst. 2 O 3 Oxidized to As 2 O 5 ; and then use As 2 O 5 The property of being easily soluble in water enables the removal of arsenic species from the catalyst.
[0025] 2. The present invention utilizes a weakly alkaline environment to convert gaseous O 3 It is converted into ·OH and active O atoms in the liquid system, thereby significantly improving the adequacy of the contact between the catalyst and the oxidant and realizing the application of ozone advanced oxidation process in catalyst regeneration.
[0026] 3. HO generated during the reaction of the present invention 2 - V present in the regenerated catalyst 4+ Oxidized to V 5+ , adjust the effective valence state of the active components of the catalyst, and optimize the V 4+ / V 5+ The purpose of the ratio is to achieve vanadium regeneration to a certain extent and reduce the demand for vanadium supplementation during catalyst regeneration. 2 -It can also oxidize and remove carbon deposits on the catalyst surface, so that the specific surface area and pores of the catalyst can be restored, which is beneficial for the catalyst to adsorb nitrogen oxides. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 The comparative XRD diffraction patterns of the catalyst before and after regeneration in Example 1 of the present invention are shown in FIG.
[0028] Figure 2 This is a comparative SEM scanning electron microscope image of the catalyst before and after regeneration in Example 1 of the present invention. DETAILED DESCRIPTION
[0029] The present invention is further described below in conjunction with specific implementation modes.
[0030] Example 1
[0031] A method for regenerating an arsenic-poisoned SCR denitration catalyst comprises the following steps:
[0032] (1) The treated arsenic-poisoned SCR denitration catalyst is collected, and firstly mechanically purged and deashed to remove the accumulated dust on the surface of the treated catalyst. Then, the treated catalyst is cut and put into a crusher for crushing, and then sorted and sieved to select catalyst powder with a particle size of 200 to 300 meshes; in this embodiment, the arsenic-poisoned SCR denitration catalyst is specifically a vanadium-tungsten-titanium honeycomb SCR denitration catalyst, specifically a vanadium-tungsten-titanium honeycomb SCR denitration catalyst with a height of 100 mm and 13×13 holes.
[0033] (2) The catalyst powder treated in step (1) is added to a pre-prepared 0.5 mol / L monoethanolamine solution, and a mixed gas of ozone, oxygen and nitrogen with an ozone concentration of 10 mg / L is introduced at the same time, and the mixture is placed in a water bath at 80° C. and soaked and cleaned for 120 minutes, with continuous stirring during the cleaning process.
[0034] (3) The catalyst powder treated in step (2) was repeatedly rinsed with deionized water, and then the catalyst powder was placed in an oven and dried at 105° C. for 8 h.
[0035] (4) placing the catalyst powder treated in step (3) in a regeneration solution for 30 minutes; the weight percentage of ammonium metavanadate in the regeneration solution is 0.2 wt %, the weight percentage of ammonium metatungstate in the aqueous solution is 0.1 wt %, and the weight percentage of ammonium heptamolybdate in the aqueous solution is 0.3 wt %.
[0036] (5) The catalyst powder treated in step (4) is transferred to a muffle furnace and heated to 500° C. at a rate of 10° C. / min, and calcined at this temperature for 4 h to obtain a regenerated catalyst.
[0037] The catalysts before and after regeneration were characterized and tested, and the obtained XRD diffraction patterns were as follows: Figure 1 As shown, the SEM scanning electron microscope image is as follows Figure 2 As shown. Figure 1 It can be seen that the main phase of the spent catalyst and the detoxified catalyst is anatase-type titanium dioxide, and no crystal phases of As, V and W are detected. This may be due to their low content and amorphous state. The crystal structure of the catalyst is not destroyed after denitration. ; From Figure 2It can be seen that the SEM image of the detoxified catalyst is significantly different from that of the spent catalyst, indicating that the process has a positive performance in removing aggregates.
[0038] The results showed that compared with the treated catalyst before regeneration, the arsenic removal rate of the regenerated catalyst reached 88.25%.
[0039] The performance of the regenerated catalyst was evaluated using simulated flue gas conditions, with NH3 as the reducing agent and flue gas conditions: the mass fraction of NO was 500ppm, NH 3 The mass fraction of O is 500ppm, 2 The mass fraction of N is 5 vol%. 2 For balance gas, the air speed is 120000h -1 When the reaction temperature is 350℃, the denitrification efficiency is 91.50%.
[0040] Example 2
[0041] A method for regenerating an arsenic-poisoned SCR denitration catalyst comprises the following steps:
[0042] (1) The treated arsenic-poisoned SCR denitration catalyst is collected, and firstly mechanically purged and deashed to remove the accumulated dust on the surface of the treated catalyst. Then, the treated catalyst is cut and put into a crusher for crushing, and then sorted and sieved to select catalyst powder with a particle size of 200 to 300 meshes; in this embodiment, the arsenic-poisoned SCR denitration catalyst is specifically a vanadium-tungsten-titanium honeycomb SCR denitration catalyst, specifically a vanadium-tungsten-titanium honeycomb SCR denitration catalyst with a height of 100 mm and 13×13 holes.
[0043] (2) The catalyst powder treated in step (1) is added to a pre-prepared 0.5 mol / L ammonia solution, and a mixed gas of ozone, oxygen and nitrogen with an ozone concentration of 10 mg / L is introduced at the same time. The powder is placed in a water bath at 80° C. and soaked and cleaned for 120 minutes, with continuous stirring during the cleaning process.
[0044] (3) The catalyst powder treated in step (2) was repeatedly rinsed with deionized water, and then the catalyst powder was placed in an oven and dried at 105° C. for 8 h.
[0045] (4) placing the catalyst powder treated in step (3) in a regeneration solution for 30 minutes; the weight percentage of ammonium metavanadate in the regeneration solution is 0.2 wt %, the weight percentage of ammonium metatungstate in the aqueous solution is 0.1 wt %, and the weight percentage of ammonium heptamolybdate in the aqueous solution is 0.3 wt %.
[0046] (5) The catalyst powder treated in step (4) is transferred to a muffle furnace and heated to 500° C. at a rate of 10° C. / min, and calcined at this temperature for 4 h to obtain a regenerated catalyst.
[0047] The regenerated catalyst was characterized and tested, and the results showed that the arsenic removal rate of the regenerated catalyst reached 89.60% compared with the treated catalyst before regeneration.
[0048] The performance of the regenerated catalyst was evaluated using simulated flue gas conditions, with NH3 as the reducing agent and flue gas conditions: the mass fraction of NO was 500ppm, NH 3 The mass fraction of O is 500ppm, 2 The mass fraction of N is 5 vol%. 2 For balance gas, the air speed is 120000h -1 When the reaction temperature is 350℃, the denitrification efficiency is 91.80%.
[0049] Example 3
[0050] A method for regenerating an arsenic-poisoned SCR denitration catalyst comprises the following steps:
[0051] (1) The treated arsenic-poisoned SCR denitration catalyst is collected, and firstly mechanically purged and deashed to remove the accumulated dust on the surface of the treated catalyst. Then, the treated catalyst is cut and put into a crusher for crushing, and then sorted and sieved to select catalyst powder with a particle size of 200 to 300 meshes; in this embodiment, the arsenic-poisoned SCR denitration catalyst is specifically a vanadium-tungsten-titanium honeycomb SCR denitration catalyst, specifically a vanadium-tungsten-titanium honeycomb SCR denitration catalyst with a height of 100 mm and 13×13 holes.
[0052] (2) The catalyst powder treated in step (1) is added to a pre-prepared 0.5 mol / L ammonium bicarbonate solution, and a mixed gas of ozone, oxygen and nitrogen with an ozone concentration of 10 mg / L is introduced at the same time, and the mixture is placed in a water bath at 80° C. and soaked and cleaned for 120 minutes, with continuous stirring during the cleaning process.
[0053] (3) The catalyst powder treated in step (2) was repeatedly rinsed with deionized water, and then the catalyst powder was placed in an oven and dried at 105° C. for 8 h.
[0054] (4) placing the catalyst powder treated in step (3) in a regeneration solution for 30 minutes; the weight percentage of ammonium metavanadate in the regeneration solution is 0.2 wt %, the weight percentage of ammonium metatungstate in the aqueous solution is 0.1 wt %, and the weight percentage of ammonium heptamolybdate in the aqueous solution is 0.3 wt %.
[0055] (5) The catalyst powder treated in step (4) is transferred to a muffle furnace and heated to 500° C. at a rate of 10° C. / min, and calcined at this temperature for 4 h to obtain a regenerated catalyst.
[0056] The regenerated catalyst was characterized and tested, and the results showed that the arsenic removal rate of the regenerated catalyst was 87.35% compared with the treated catalyst before regeneration.
[0057] The performance of the regenerated catalyst was evaluated using simulated flue gas conditions, with NH3 as the reducing agent and flue gas conditions: the mass fraction of NO was 500ppm, NH 3 The mass fraction of O is 500ppm, 2 The mass fraction of N is 5 vol%. 2 For balance gas, the air speed is 120000h -1 When the reaction temperature is 350℃, the denitrification efficiency is 90.10%.
[0058] Example 4
[0059] A method for regenerating an arsenic-poisoned SCR denitration catalyst comprises the following steps:
[0060] (1) The treated arsenic-poisoned SCR denitration catalyst is collected, and firstly mechanically purged and deashed to remove the accumulated dust on the surface of the treated catalyst. Then, the treated catalyst is cut and put into a crusher for crushing, and then sorted and sieved to select catalyst powder with a particle size of 200 to 300 meshes; in this embodiment, the arsenic-poisoned SCR denitration catalyst is specifically a vanadium-tungsten-titanium honeycomb SCR denitration catalyst, specifically a vanadium-tungsten-titanium honeycomb SCR denitration catalyst with a height of 100 mm and 13×13 holes.
[0061] (2) The catalyst powder treated in step (1) is added to a pre-prepared 1.0 mol / L monoethanolamine solution, and a mixed gas of ozone, oxygen and nitrogen with an ozone concentration of 10 mg / L is introduced at the same time, and the mixture is placed in a water bath at 80° C. and soaked and cleaned for 120 minutes, with continuous stirring during the cleaning process.
[0062] (3) The catalyst powder treated in step (2) was repeatedly rinsed with deionized water, and then the catalyst powder was placed in an oven and dried at 105° C. for 8 h.
[0063] (4) placing the catalyst powder treated in step (3) in a regeneration solution for 30 minutes; the weight percentage of ammonium metavanadate in the regeneration solution is 0.2 wt %, the weight percentage of ammonium metatungstate in the aqueous solution is 0.1 wt %, and the weight percentage of ammonium heptamolybdate in the aqueous solution is 0.3 wt %.
[0064] (5) The catalyst powder treated in step (4) is transferred to a muffle furnace and heated to 500° C. at a rate of 10° C. / min, and calcined at this temperature for 4 h to obtain a regenerated catalyst.
[0065] The regenerated catalyst was characterized and tested, and the results showed that the arsenic removal rate of the regenerated catalyst reached 89.75% compared with the treated catalyst before regeneration.
[0066] The performance of the regenerated catalyst was evaluated using simulated flue gas conditions, with NH3 as the reducing agent and flue gas conditions: the mass fraction of NO was 500ppm, NH 3 The mass fraction of O is 500ppm, 2 The mass fraction of N is 5 vol%. 2 For balance gas, the air speed is 120000h -1 When the reaction temperature is 350℃, the denitrification efficiency is 92.40%.
[0067] Example 5
[0068] A method for regenerating an arsenic-poisoned SCR denitration catalyst comprises the following steps:
[0069] (6) Collect the treated arsenic-poisoned SCR denitration catalyst, first perform mechanical purging and deashing on it, and remove the dust accumulated on the surface of the treated catalyst. Then, cut the treated catalyst, put it into a crusher for crushing, and select and sieve it to select catalyst powder with a particle size of 200-300 mesh; In this embodiment, the arsenic-poisoned SCR denitration catalyst is specifically a vanadium-tungsten-titanium honeycomb SCR denitration catalyst, specifically a vanadium-tungsten-titanium honeycomb SCR denitration catalyst with a height of 100 mm and 13×13 holes.
[0070] (7) The catalyst powder treated in step (1) is added to a pre-prepared 1.0 mol / L ammonia solution, and a mixed gas of ozone, oxygen and nitrogen with an ozone concentration of 10 mg / L is introduced at the same time. The powder is placed in a water bath at 80° C. and soaked and cleaned for 120 minutes, with continuous stirring during the cleaning process.
[0071] (8) The catalyst powder treated in step (2) was repeatedly rinsed with deionized water, and then the catalyst powder was placed in an oven and dried at 105° C. for 8 h.
[0072] (9) placing the catalyst powder treated in step (3) in a regeneration solution for 30 min; the weight percentage of ammonium metavanadate in the regeneration solution is 0.2 wt %, the weight percentage of ammonium metatungstate in the aqueous solution is 0.1 wt %, and the weight percentage of ammonium heptamolybdate in the aqueous solution is 0.3 wt %.
[0073] (10) The catalyst powder treated in step (4) is transferred to a muffle furnace and heated to 500° C. at a rate of 10° C. / min, and calcined at this temperature for 4 h to obtain a regenerated catalyst.
[0074] The regenerated catalyst was characterized and tested, and the results showed that compared with the treated catalyst before regeneration, the arsenic removal rate of the regenerated catalyst reached 90.45%.
[0075] The performance of the regenerated catalyst was evaluated using simulated flue gas conditions, with NH3 as the reducing agent and flue gas conditions: the mass fraction of NO was 500ppm, NH 3 The mass fraction of O is 500ppm, 2 The mass fraction of N is 5 vol%. 2 For balance gas, the air speed is 120000h -1 When the reaction temperature is 350℃, the denitrification efficiency is 93.10%.
[0076] Example 6
[0077] A method for regenerating an arsenic-poisoned SCR denitration catalyst comprises the following steps:
[0078] (1) The treated arsenic-poisoned SCR denitration catalyst is collected, and firstly mechanically purged and deashed to remove the accumulated dust on the surface of the treated catalyst. Then, the treated catalyst is cut and put into a crusher for crushing, and then sorted and sieved to select catalyst powder with a particle size of 200 to 300 meshes; in this embodiment, the arsenic-poisoned SCR denitration catalyst is specifically a vanadium-tungsten-titanium honeycomb SCR denitration catalyst, specifically a vanadium-tungsten-titanium honeycomb SCR denitration catalyst with a height of 100 mm and 13×13 holes.
[0079] (2) The catalyst powder treated in step (1) is added to a pre-prepared 1.0 mol / L ammonium bicarbonate solution, and a mixed gas of ozone, oxygen and nitrogen with an ozone concentration of 10 mg / L is introduced at the same time, and the mixture is placed in a water bath at 80° C. and soaked and cleaned for 120 minutes, with continuous stirring during the cleaning process.
[0080] (3) The catalyst powder treated in step (2) was repeatedly rinsed with deionized water, and then the catalyst powder was placed in an oven and dried at 105° C. for 8 h.
[0081] (4) placing the catalyst powder treated in step (3) in a regeneration solution for 30 minutes; the weight percentage of ammonium metavanadate in the regeneration solution is 0.2 wt %, the weight percentage of ammonium metatungstate in the aqueous solution is 0.1 wt %, and the weight percentage of ammonium heptamolybdate in the aqueous solution is 0.3 wt %.
[0082] (5) The catalyst powder treated in step (4) is transferred to a muffle furnace and heated to 500° C. at a rate of 10° C. / min, and calcined at this temperature for 4 h to obtain a regenerated catalyst.
[0083] The regenerated catalyst was characterized and tested, and the results showed that the arsenic removal rate of the regenerated catalyst was 89.05% compared with the treated catalyst before regeneration.
[0084] The performance of the regenerated catalyst was evaluated using simulated flue gas conditions, with NH3 as the reducing agent and flue gas conditions: the mass fraction of NO was 500ppm, NH 3 The mass fraction of O is 500ppm, 2 The mass fraction of N is 5 vol%. 2 For balance gas, the air speed is 120000h -1 When the reaction temperature is 350℃, the denitrification efficiency is 91.20%.
[0085] Example 7
[0086] A method for regenerating an arsenic-poisoned SCR denitration catalyst, the difference between this embodiment and embodiment 1 is that the regenerated SCR denitration catalyst is a cerium-titanium SCR denitration catalyst and a cerium-tungsten-titanium SCR denitration catalyst. Cerium nitrate and ammonium metatungstate are dissolved in the regeneration liquid in step (4).
Claims
1. A method for regenerating an arsenic-poisoned SCR denitration catalyst; characterized in that: The following steps are involved: Step 1, crushing, grinding and screening the regenerated SCR denitration catalyst to obtain catalyst powder; the regenerated SCR denitration catalyst is a vanadium-tungsten-titanium system denitration catalyst; Step 2, placing the catalyst powder obtained in step 1 in an alkaline solution for soaking and cleaning; and introducing a mixed gas of ozone, oxygen and nitrogen into the alkaline solution for stirring and reaction; the pH value of the alkaline solution is 9.0-13.0; the concentration of ozone in the mixed gas of ozone, oxygen and nitrogen is 1 mg / L-50 mg / L; the alkaline solution is a mixture of one or more alkaline solutions of ammonia water, ammonium bicarbonate solution and monoethanolamine solution, and the solution concentration is 0.1-5.0 mol / L, and the cleaning time is 10-240 min; Step 3, washing and drying the solid product obtained in step 2; Step 4, immersing the solid product obtained in step 3 in a regeneration solution; the regeneration solution contains ammonium metavanadate, ammonium metatungstate and ammonium heptamolybdate, and the immersion time is 0.5h~3.0h; the mass concentrations of ammonium metavanadate, ammonium metatungstate and ammonium heptamolybdate in the regeneration solution are all 0.1wt%~2.0wt%; Step 5: calcine the solid product obtained in step 4 to obtain a regenerated SCR denitration catalyst.
2. The method for regenerating an arsenic-poisoned SCR denitration catalyst according to claim 1, characterized in that: Before the crushing, grinding and screening in step 1, the regenerated SCR denitration catalyst is purged and deashed.
3. The method for regenerating an arsenic-poisoned SCR denitration catalyst according to claim 1, characterized in that: The regenerated SCR denitration catalyst is a honeycomb type or a flat plate type catalyst.
4. The method for regenerating an arsenic-poisoned SCR denitration catalyst according to claim 1, characterized in that: The particle size of the catalyst powder obtained in step 1 is 200-300 mesh.
5. The method for regenerating an arsenic-poisoned SCR denitration catalyst according to claim 1, characterized in that: In step 3, the drying temperature is 80-130° C. and the drying time is 8-16 hours.
6. The method for regenerating an arsenic-poisoned SCR denitration catalyst according to claim 1, characterized in that: In step 5, the calcination temperature is 450-600° C., the heating rate is 10-30° C. / min, and the calcination time is 2-12 h.