Recycling and regenerating process of denitration catalyst and treatment method of regenerated wastewater of denitration catalyst

Abstract

The invention discloses a regeneration process of a selective catalytic reduction denitration catalyst module and a wastewater treatment method thereof, and the regeneration process comprises the following steps: washing for three times after physical ash removal, and collecting wastewater I; sequentially carrying out two-time alkali washing and one-time water washing, and collecting wastewater II; finally, sequentially carrying out two times of acid pickling and one time of water washing, and collecting wastewater III; and drying, adding into the loading liquid, reacting, drying and roasting to obtain the denitration catalyst module with recovered activity. According to the cleaning process, the impurity removal effect is good, the addition of organic matters is reduced, so that the subsequent wastewater treatment cost is reduced, the wastewater I, the wastewater II and the wastewater III are respectively treated firstly, then the total wastewater is treated, finally, the wastewater is successfully discharged after reaching the standard, meanwhile, the acid consumption or alkali consumption in the wastewater treatment process is effectively reduced and neutralized, and the environmental pollution is reduced. And the enrichment of valuable metals can be realized, and further recycling is facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental engineering, and in particular relates to a denitration catalyst recovery and regeneration process and a method for treating regeneration wastewater thereof. Background Art

[0002] Selective Catalytic Reduction (SCR) is a method for removing NO from flue gas in coal-fired power plants. X The main method is to use ammonia to remove NO in flue gas. x Reduction to N2. V2O5-WO3 / TiO2 catalysts are the mainstream denitrification catalysts used in power plants. Due to the effects of harmful components in flue gas, the catalyst's activity gradually decreases over time, resulting in a new catalyst's service life of typically 3 to 5 years. Currently, regeneration is often the preferred method for initial catalyst replacement.

[0003] Methods for treating denitrification catalyst regeneration wastewater include acid-base neutralization, adsorption, electrochemical, biological, and Fenton methods. Acid-base neutralization is mainly used to remove heavy metals, while adsorption, electrochemical, biological, and Fenton methods can be used to remove COD from wastewater. The organic matter content in denitrification catalysts is extremely low, and the high COD content is mainly due to organic matter such as surfactants in the cleaning process. Therefore, if the addition of organic matter can be reduced as much as possible while ensuring the cleaning effect, it is of great significance to reducing the cost of wastewater treatment. In addition, in existing wastewater treatment, valuable metals are often mixed with ash from the catalyst after precipitation, resulting in a low content of valuable metals in the solid waste and low recovery value.

[0004] If a suitable regeneration process can be developed to achieve effective regeneration of the catalyst and low-cost disposal of wastewater at the same time, it will be a direction that the denitrification catalyst regeneration industry urgently needs to pay attention to. Summary of the Invention

[0005] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and in the abstract and title of the present invention to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a process for recovering and regenerating a denitration catalyst.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0009] The recovered block denitration catalyst is physically cleaned and then washed three times to obtain a denitration catalyst module I, and wastewater I is collected;

[0010] The denitration catalyst module I is sequentially subjected to two alkali washes and one water wash to obtain a denitration catalyst module II, and wastewater II is collected;

[0011] The denitration catalyst module II is sequentially subjected to two acid washes and one water wash to obtain a denitration catalyst module III, and wastewater III is collected;

[0012] The dried denitration catalyst module III is added to the loading liquid for reaction, and then dried and calcined to obtain a denitration catalyst module with restored activity;

[0013] The two alkali washings, wherein the first alkali washing is performed by bubbling, the second alkali washing is performed by ultrasound, the time of each alkali washing is 10 to 60 minutes, the water temperature of each alkali washing is 20 to 70° C., and the alkali detergent component of each alkali washing includes one or more of NaOH, KOH, and Na2CO3;

[0014] The two picklings are performed by bubbling for the first pickling and ultrasonically for the second pickling. The time for each pickling is 10 to 60 minutes, the water temperature for each pickling is 20 to 70° C., and the pickling agent components for each pickling include one or more of H2SO4, H2C2O4, EDTA, HCl, and HNO3.

[0015] As a preferred solution of the denitration catalyst recovery and regeneration process of the present invention, the physical dust cleaning includes manually scraping off the dust on the surface of the denitration catalyst module and then blowing away the loose dust on the surface with compressed air.

[0016] As a preferred solution of the denitration catalyst recovery and regeneration process of the present invention, wherein: the three water washings are all performed by bubbling combined with ultrasonic cleaning,

[0017] The three water washes include three water changes, wherein:

[0018] When the turbidity of the water for the first wash is greater than 3000, change the water;

[0019] When the turbidity of the water for the second wash is greater than 2000, change the water;

[0020] When the turbidity of the water for the third wash is greater than 1000, change the water.

[0021] As a preferred solution of the denitration catalyst recovery and regeneration process of the present invention, the bubbling pressure is 0.1-0.4 MPa, and the ultrasonic power is 20-40 kHz.

[0022] As a preferred solution of the denitration catalyst recovery and regeneration process of the present invention, the components of the loading liquid include one or more of ammonium metavanadate, vanadyl sulfate, ammonium metatungstate, and ammonium molybdate.

[0023] As a preferred solution of the denitration catalyst recovery and regeneration process described in the present invention, the denitration catalyst module III after drying is added to the load liquid for reaction, wherein the drying temperature is 150-280°C, the drying time is 1-4 hours, the reaction temperature is 10-60°C, and the reaction time is 10-30 minutes.

[0024] As a preferred solution of the denitration catalyst recovery and regeneration process described in the present invention, the drying and calcining obtain a denitration catalyst module with restored activity, wherein the drying temperature is 150-250°C, the drying time is 1-3 hours, the calcining temperature is 300-420°C, and the calcining time is 1-3 hours.

[0025] Another object of the present invention is to overcome the deficiencies in the prior art and provide a method for treating regeneration wastewater in a denitration catalyst recovery and regeneration process.

[0026] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0027] The wastewater I is filtered through a plate and frame filter to obtain wastewater I';

[0028] After the wastewater II is filtered through a plate and frame filter, calcium oxide is added and precipitated for 10 to 30 minutes to remove arsenic, vanadium and tungsten precipitated during the alkaline washing process, and then filtered through a plate and frame filter to obtain wastewater II' and valuable metal enriched slag I;

[0029] The wastewater III is filtered through a plate and frame filter to obtain wastewater III';

[0030] Wastewater I', wastewater II' and wastewater III' are collected and collected to obtain wastewater IV. The pH of wastewater IV is adjusted to 6.5-9, and an oxidant and a flocculant are added in sequence to react for 10-30 minutes. The valuable metal-enriched slag II is obtained after plate and frame filtration.

[0031] As a preferred solution for the treatment method of regenerated wastewater in the denitration catalyst recovery and regeneration process of the present invention, the ratio of the mass of the oxidant to the total mass of COD and ammonia nitrogen in the wastewater IV is 3 to 8:1.

[0032] As a preferred solution of the method for treating regenerated wastewater in the denitration catalyst recovery and regeneration process of the present invention, the amount of the flocculant added is 20 to 500 mg / L compared to the IV of the wastewater.

[0033] Beneficial effects of the present invention:

[0034] (1) The present invention adopts a cleaning process combining multiple water washes, two alkali washes and two acid washes, which has a good impurity removal effect and a wide coverage, and strictly controls the addition of organic matter during the cleaning process, thereby reducing the subsequent wastewater treatment cost;

[0035] (2) In terms of wastewater treatment, the COD content of wastewater in this process is lower than that of the existing technology. The wastewater from water washing, alkali washing and acid washing is first treated separately and then mixed for treatment. This can effectively reduce and neutralize the acid or alkali consumption in the wastewater treatment process, achieve the enrichment of valuable metals, facilitate further recycling and utilization, and ensure that the wastewater meets the discharge standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0037] Figure 1 This is a flow chart of the regeneration process of the selective catalytic reduction denitration catalyst and the wastewater treatment method thereof in Examples 1 to 3 of the present invention. DETAILED DESCRIPTION

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0039] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0040] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0041] Example 1

[0042] This embodiment provides a denitration catalyst recovery and regeneration process, specifically:

[0043] (1) Physical cleaning: The denitration catalyst module used in this example is a honeycomb type with 18 holes, has a service life of about 5 years, and has a size of 150 mm * 150 mm * 865 mm. The dust on the surface of the denitration catalyst module is first manually scraped off, and then the loose dust on the surface is blown away with 0.3 MPa compressed air. The blowing time is 10 minutes.

[0044] (2) Water washing: the denitration catalyst module after physical cleaning is placed in a cleaning tank, water is added to cover the denitration catalyst module by 10 cm, and the module is washed three times in sequence by bubbling combined with ultrasound to obtain the denitration catalyst module I, and wastewater I is collected, wherein the bubbling pressure of each water washing is 0.4 MPa, the ultrasonic power is 30 kHz, the time of each water washing is 30 min, and the water temperature is 40 ° C; during the first water washing, when the water turbidity exceeds 3000, the water is changed; during the second water washing, when the water turbidity exceeds 2000, the water is changed; during the third water washing, when the water turbidity exceeds 1000, the water is changed;

[0045] (3) Alkali washing: The denitration catalyst module I was subjected to alkali washing twice in sequence, wherein each alkali washing time was 30 min, the water temperature was 70° C., and the water was changed once during each alkali washing process for cleaning 6 denitration catalyst modules I;

[0046] The first alkaline washing was performed by bubbling a mixed solution of NaOH, KOH, and Na2CO3, wherein the NaOH concentration in the mixed solution was 9 g / L, the KOH concentration was 3 g / L, the Na2CO3 concentration was 3 g / L, and the bubbling pressure was 0.4 MPa; the second alkaline washing was performed by ultrasonic cleaning using a NaOH solution, wherein the NaOH concentration was 7.5 g / L and the ultrasonic power was 30 kHz;

[0047] After the alkaline washing is completed, a water washing is performed once, the washing time is 30 minutes, the water temperature is 50°C, and the denitration catalyst module II is obtained, and the wastewater II is collected;

[0048] (4) Pickling: The denitration catalyst module II was pickled twice in sequence, wherein each pickling time was 30 min, the water temperature was 25°C, and the water was changed once during each pickling process for cleaning 6 denitration catalyst modules II;

[0049] The first pickling was performed by bubbling a mixed solution of H2SO4 and EDTA, wherein the H2SO4 concentration in the mixed solution was 0.3wt%, the EDTA concentration was 0.02wt%, and the bubbling pressure was 0.4MPa; the second cleaning was performed by ultrasonic cleaning using a H2SO4 solution, wherein the H2SO4 solution concentration was 0.2wt% and the ultrasonic power was 20KHz;

[0050] After the acid wash, the module was washed once with water for 30 minutes at a temperature of 25°C to obtain the denitration catalyst module III, and wastewater III was collected;

[0051] (5) Restoring activity: The denitration catalyst module III was dried at 200°C for 2 hours, added to a loading liquid and reacted at 50°C for 15 minutes, then dried at 200°C for 2 hours and then calcined at 400°C for 1 hour to obtain a denitration catalyst module with restored activity, wherein the loading liquid is an aqueous solution composed of 0.83 wt% vanadyl sulfate and 0.38 wt% ammonium metatungstate.

[0052] Example 2

[0053] This embodiment provides a method for treating regeneration wastewater in a denitration catalyst recovery and regeneration process, specifically:

[0054] (1) First wastewater treatment: Wastewater I generated in Example 1 was filtered through a plate and frame filter to obtain wastewater I';

[0055] (2) Secondary wastewater treatment: The wastewater II produced in Example 1 was filtered through a plate and frame system, and then calcium oxide was added and precipitated for 30 minutes to remove arsenic (As), vanadium (V), and tungsten (W) precipitated during the alkali washing process, wherein n(Ca) / n(As+V+W)=4:1 (stoichiometric ratio). The wastewater II' and valuable metal-enriched slag I were then filtered through a plate and frame system.

[0056] (3) Third wastewater treatment: Wastewater III generated in Example 1 is filtered through a plate and frame filter to obtain wastewater III';

[0057] (4) The fourth wastewater treatment: Wastewater I', wastewater II', and wastewater III' were collected and collected to obtain wastewater IV. The pH of wastewater IV was adjusted to 8, and sodium hypochlorite (oxidant) and polyferric chloride (flocculant) were added in sequence to react for 30 min. The ratio of the mass of sodium hypochlorite to the total mass of COD and ammonia nitrogen in wastewater IV was 5:1, and the amount of polyferric chloride added to wastewater IV was 50 mg / L.

[0058] After the reaction is completed, valuable metal-enriched slag II and final wastewater are obtained through plate and frame filtration.

[0059] Example 3

[0060] This embodiment provides a denitration catalyst recovery and regeneration process, specifically:

[0061] (1) Physical cleaning: The catalyst module used in this example is a honeycomb-type, 18-hole, and has a service life of about 5 years. The size is 150mm*150mm*1090mm. The dust on the surface of the denitration catalyst module is first manually scraped off, and then the loose dust on the surface is blown away with 0.3MPa compressed air. The blowing time is 10 minutes.

[0062] (2) Water washing: the denitration catalyst module after physical cleaning is placed in a cleaning tank, water is added to cover the denitration catalyst module by 10 cm, and the module is washed three times in sequence by bubbling combined with ultrasound to obtain the denitration catalyst module I, and wastewater I is collected, wherein the bubbling pressure of the three water washings is 0.4 MPa, the ultrasonic power is 40 kHz, the time of each water washing is 20 min, and the water temperature is 50 ° C; during the first water washing, when the water turbidity exceeds 3000, the water is changed; during the second water washing, when the water turbidity exceeds 2000, the water is changed; during the third water washing, when the water turbidity exceeds 1000, the water is changed;

[0063] (3) Alkali washing: The denitration catalyst module I was subjected to alkali washing twice in sequence, wherein each alkali washing time was 30 min, the water temperature was 60° C., and the water was changed once during each alkali washing process for cleaning 6 denitration catalyst modules I;

[0064] The first alkaline washing was performed by bubbling a mixed solution of NaOH and Na2CO3, wherein the NaOH concentration in the mixed solution was 10 g / L, the Na2CO3 concentration was 2 g / L, and the bubbling pressure was 0.4 MPa; the second alkaline washing was performed by ultrasonically cleaning a mixed solution of NaOH and Na2CO3, wherein the NaOH concentration was 5 g / L, the Na2CO3 concentration was 2 g / L, and the ultrasonic power was 20 kHz;

[0065] After the alkaline washing is completed, a water washing is performed once, the washing time is 30 minutes, the water temperature is 25°C, and the denitration catalyst module II is obtained, and the wastewater II is collected;

[0066] (4) Pickling: The denitration catalyst module II was pickled twice in sequence, wherein each pickling time was 30 min, the water temperature was 25°C, and the water was changed once during each pickling process for cleaning 6 denitration catalyst modules II;

[0067] The first pickling was performed by bubbling a mixed solution of H2SO4 and EDTA, wherein the H2SO4 concentration in the mixed solution was 0.5wt%, the EDTA concentration was 0.05wt%, and the bubbling pressure was 0.4MPa; the second cleaning was performed by ultrasonic cleaning using a H2SO4 solution, wherein the H2SO4 concentration was 0.3wt% and the ultrasonic power was 40KHz;

[0068] After the acid wash, the module was washed once with water for 30 minutes at a temperature of 25°C to obtain the denitration catalyst module III, and wastewater III was collected;

[0069] (5) Restoring activity: The denitration catalyst module III was dried at 200°C for 3 hours, added to a loading liquid and reacted at 30°C for 20 minutes, and then dried at 200°C for 3 hours and then calcined at 380°C for 2 hours to obtain a denitration catalyst module with restored activity, wherein the loading liquid is an aqueous solution composed of 1.04 wt% vanadyl sulfate and 0.5 wt% ammonium metatungstate.

[0070] Example 4

[0071] This embodiment provides a method for treating regeneration wastewater in a denitration catalyst recovery and regeneration process, specifically:

[0072] (1) First wastewater treatment: Wastewater I generated in Example 3 was filtered through a plate and frame filter to obtain wastewater I';

[0073] (2) Secondary wastewater treatment: After the wastewater II produced in Example 3 was filtered through a plate and frame filter, calcium oxide was added and precipitated for 30 minutes to remove arsenic (As), vanadium (V), and tungsten (W) precipitated during the alkaline washing process.

[0074] Among them, n(Ca) / n(As+V+W)=2:1 (stoichiometric ratio), and then the wastewater II' and valuable metal enriched slag I are obtained by plate and frame filtration;

[0075] (3) Third wastewater treatment: Wastewater III generated in Example 3 is filtered through a plate and frame filter to obtain wastewater III';

[0076] (4) The fourth wastewater treatment: Wastewater I', wastewater II', and wastewater III' were collected and collected to obtain wastewater IV. The pH of wastewater IV was adjusted to 7, and sodium hypochlorite and polyferric chloride were added in sequence to react for 20 min. The ratio of the mass of sodium hypochlorite to the total mass of COD and ammonia nitrogen in wastewater IV was 7:1, and the amount of polyferric chloride added to wastewater IV was 100 mg / L.

[0077] After the reaction is completed, valuable metal-enriched slag II and final wastewater are obtained through plate and frame filtration.

[0078] Example 5

[0079] This embodiment provides a denitration catalyst recovery and regeneration process, specifically:

[0080] (1) Physical cleaning: The denitration catalyst module used in this example is a honeycomb type with 18 holes, has been in use for about 6 years, and has dimensions of 150 mm * 150 mm * 765 mm. The dust accumulated on the surface of the denitration catalyst module is first manually scraped off, and then the loose dust on the surface is blown away with 0.3 MPa compressed air. The blowing time is 10 minutes.

[0081] (2) Water washing: the denitration catalyst module after physical cleaning is placed in a cleaning tank, water is added to cover the denitration catalyst module by 10 cm, and the module is washed three times in sequence by bubbling combined with ultrasound to obtain the denitration catalyst module I, and wastewater I is collected, wherein the bubbling pressure of each water washing is 0.2 MPa, the ultrasonic power is 20 kHz, the time of each water washing is 30 min, and the water temperature is 25 ° C; during the first water washing, when the water turbidity exceeds 3000, the water is changed; during the second water washing, when the water turbidity exceeds 2000, the water is changed; during the third water washing, when the water turbidity exceeds 1000, the water is changed;

[0082] (3) Alkali washing: The denitration catalyst module I was subjected to alkali washing twice in sequence, wherein each alkali washing time was 30 min, the water temperature was 60° C., and the water was changed once during each alkali washing process for cleaning 6 denitration catalyst modules I;

[0083] The first alkaline washing was performed by bubbling a mixed solution of NaOH and KOH, wherein the NaOH concentration in the mixed solution was 8 g / L, the KOH concentration was 3 g / L, and the bubbling pressure was 0.4 MPa; the second alkaline washing was performed by ultrasonically cleaning a mixed solution of NaOH and Na2CO3, wherein the NaOH concentration was 4 g / L, the Na2CO3 concentration was 1 g / L, and the ultrasonic power was 20 kHz;

[0084] After the alkaline washing is completed, a water washing is performed once, the washing time is 30 minutes, the water temperature is 25°C, and the denitration catalyst module II is obtained, and the wastewater II is collected;

[0085] (4) Pickling: The denitration catalyst module II was pickled twice in sequence, wherein each pickling time was 30 min, the water temperature was 25°C, and the water was changed once during each pickling process for cleaning 6 denitration catalyst modules II;

[0086] The first pickling was performed by bubbling a mixed solution of H2SO4 and EDTA, wherein the H2SO4 concentration in the mixed solution was 0.43wt%, the EDTA concentration was 0.03wt%, and the bubbling pressure was 0.4MPa; the second cleaning was performed by ultrasonic cleaning using a H2SO4 solution, wherein the H2SO4 concentration was 0.23wt% and the ultrasonic power was 30KHz;

[0087] After the acid wash, the module was washed with water for 30 min at a water temperature of 25° C. to obtain the denitration catalyst module III, and wastewater III was collected.

[0088] (5) Restoring activity: The denitration catalyst module III was dried at 200°C for 1.5 hours, added to a loading liquid and reacted at 25°C for 15 minutes, and then dried at 200°C for 1.5 hours and then calcined at 380°C for 2 hours to obtain a denitration catalyst module with restored activity, wherein the loading liquid is an aqueous solution composed of 0.76 wt% vanadyl sulfate and 0.4 wt% ammonium metatungstate.

[0089] Example 6

[0090] This embodiment provides a method for treating regeneration wastewater in a denitration catalyst recovery and regeneration process, specifically:

[0091] (1) First wastewater treatment: Wastewater I generated in Example 5 was filtered through a plate and frame filter to obtain wastewater I';

[0092] (2) Secondary wastewater treatment: The wastewater II produced in Example 5 was filtered through a plate and frame system, and then calcium oxide was added and precipitated for 30 minutes to remove arsenic (As), vanadium (V), and tungsten (W) precipitated during the alkali washing process, wherein n(Ca) / n(As+V+W)=5:1 (stoichiometric ratio). The wastewater II' and valuable metal-enriched slag I were then filtered through a plate and frame system.

[0093] (3) Third wastewater treatment: Wastewater III generated in Example 5 was filtered through a plate and frame filter to obtain wastewater III';

[0094] (4) The fourth wastewater treatment: Wastewater I', wastewater II', and wastewater III' were collected and collected to obtain wastewater IV. The pH of wastewater IV was adjusted to 7.5, and sodium hypochlorite and polyferric chloride were added in sequence to react for 30 min. The ratio of the mass of sodium hypochlorite to the total mass of COD and ammonia nitrogen in wastewater IV was 4:1, and the amount of polyferric chloride added to wastewater IV was 60 mg / L.

[0095] After the reaction is completed, valuable metal-enriched slag II and final wastewater are obtained through plate and frame filtration.

[0096] The activities of the denitration catalyst modules before and after treatment in Examples 1 to 6 and the components of the wastewater obtained by treatment were tested. The results are shown in Tables 1 and 2.

[0097] Table 1 Activity of denitrification catalyst module before and after treatment

[0098]

[0099] Table 2 Composition of treated wastewater

[0100]

[0101] It can be seen from Table 1 that the activity of the denitration catalysts obtained in Examples 1 to 3 is significantly improved.

[0102] As can be seen from Table 2, the wastewater components obtained by the treatment of Examples 1 to 3 all meet the discharge standards of the "Integrated Wastewater Discharge Standard" (GB 8978-1996). This is because no large amount of organic matter is added in the regeneration process of the denitrification catalyst, thereby reducing the COD content in the subsequent wastewater. At the same time, most of the heavy metal ions in the solution are removed by adding calcium first, and then the remaining heavy metal ions in the solution are adsorbed and removed by neutralization precipitation and flocculation. Finally, wastewater with a heavy metal content that meets the standards is obtained and the enrichment of valuable metals is achieved.

[0103] Comparative Example 1

[0104] The difference between this comparative example and Example 1 is that the denitration catalyst module is subjected to one bubbling water washing, one ultrasonic alkaline washing, one ultrasonic acid washing, and one bubbling water washing, and the remaining processes are the same as those in Example 1 to obtain the denitration catalyst module after treatment in this comparative example.

[0105] Comparative Example 2

[0106] The difference between this comparative example and Example 1 is that the denitration catalyst module is subjected to one bubbling water washing, one bubbling alkali washing, one bubbling acid washing, and one bubbling water washing, and the rest of the processes are the same as Example 1 to obtain the denitration catalyst module after treatment in this comparative example.

[0107] The activity of the denitration catalyst modules after treatment in Comparative Examples 1 and 2 was tested, and the results are shown in Table 3.

[0108] Table 3 Activity of the treated denitrification catalyst module

[0109]

[0110] As can be seen in Table 3, the catalyst activity recovery obtained by combining only one acid wash and one alkaline wash is low and cannot meet the requirements of use. The bubbling combined with ultrasound can promote the discharge of tiny particles in the microporous structure of the catalyst and the entry of the active solution, thereby making the loading more uniform and facilitating the recovery of activity.

[0111] In summary, the present invention provides a regeneration process for a selective catalytic reduction denitration catalyst module and a wastewater treatment method thereof. For the denitration catalyst module, two alkaline washes and two acid washes are adopted, and multiple water changes are combined during the cleaning process to finally prepare a denitration catalyst with restored activity. The cleaning process reduces the addition of organic matter, thereby reducing the cost of subsequent water treatment.

[0112] In addition, by treating the wastewater separately and then centrally treating it, the wastewater discharge meets the standards, and the acid or alkali consumption in the wastewater treatment process is effectively reduced and neutralized, achieving the enrichment of valuable metals, which is convenient for further recycling and utilization.

[0113] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A denitration catalyst recovery and regeneration process, characterized in that: include, The recovered block denitration catalyst is physically cleaned and then washed three times to obtain a denitration catalyst module I, and wastewater I is collected; The denitration catalyst module I is sequentially subjected to two alkali washes and one water wash to obtain a denitration catalyst module II, and wastewater II is collected; The denitration catalyst module II is sequentially subjected to two acid washes and one water wash to obtain a denitration catalyst module III, and wastewater III is collected; The dried denitration catalyst module III is added to the loading liquid for reaction, and then dried and calcined to obtain a denitration catalyst module with restored activity; The two alkali washings, wherein the first alkali washing is performed by bubbling, the second alkali washing is performed by ultrasound, the time of each alkali washing is 10 to 60 minutes, the water temperature of each alkali washing is 20 to 70° C., and the alkali detergent component of each alkali washing includes one or more of NaOH, KOH, and Na2CO3; The two picklings are performed by bubbling for the first pickling and ultrasonically for the second pickling. The time for each pickling is 10 to 60 minutes, the water temperature for each pickling is 20 to 70° C., and the pickling agent components for each pickling include one or more of H2SO4, H2C2O4, EDTA, HCl, and HNO3.

2. The denitration catalyst recovery and regeneration process according to claim 1, wherein: The physical dust cleaning includes manually scraping off the dust on the surface of the denitration catalyst module, and then blowing away the loose dust on the surface with compressed air.

3. The denitration catalyst recovery and regeneration process according to claim 1, wherein: The three water washings are all performed by bubbling combined with ultrasonic cleaning. The three water washes include three water changes, wherein: When the turbidity of the water for the first wash is greater than 3000, change the water; When the turbidity of the water for the second wash is greater than 2000, change the water; When the turbidity of the water for the third wash is greater than 1000, change the water.

4. The denitration catalyst recovery and regeneration process according to claim 3, wherein: The bubbling pressure is 0.1-0.4 MPa, and the ultrasonic power is 20-40 kHz.

5. The denitration catalyst recovery and regeneration process according to claim 1, wherein: The components of the loading liquid include one or more of ammonium metavanadate, vanadyl sulfate, ammonium metatungstate, and ammonium molybdate.

6. The denitration catalyst recovery and regeneration process according to claim 1, wherein: The dried denitration catalyst module III is added to the load liquid for reaction, wherein the drying temperature is 150-280° C., the drying time is 1-4 hours, the reaction temperature is 10-60° C., and the reaction time is 10-30 minutes.

7. The denitration catalyst recovery and regeneration process according to claim 1, wherein: The drying and calcining process obtains a denitration catalyst module with restored activity, wherein the drying temperature is 150-250° C., the drying time is 1-3 hours, and the calcining temperature is 300-420° C., and the calcining time is 1-3 hours.

8. A method for treating regeneration wastewater in a denitration catalyst recovery and regeneration process, characterized by: include, The wastewater I according to claim 1 is filtered through a plate and frame filter to obtain wastewater I'; The wastewater II according to claim 1 is filtered through a plate and frame filter, calcium oxide is added, and precipitation is performed for 10 to 30 minutes to remove arsenic, vanadium, and tungsten precipitated during the alkali washing process, and then filtered through a plate and frame filter to obtain wastewater II' and valuable metal-enriched slag I; The wastewater III according to claim 1 is filtered through a plate and frame filter to obtain wastewater III'; Wastewater I', wastewater II' and wastewater III' are collected and collected to obtain wastewater IV. The pH of wastewater IV is adjusted to 6.5-9, and an oxidant and a flocculant are added in sequence to react for 10-30 minutes. The valuable metal-enriched slag II is obtained after plate and frame filtration.

9. The method for treating regenerated wastewater in the denitration catalyst recovery and regeneration process according to claim 8, characterized in that: The ratio of the mass of the oxidant to the total mass of COD and ammonia nitrogen in the wastewater IV is 3 to 8:

1.

10. The method for treating regenerated wastewater in the denitration catalyst recovery and regeneration process according to claim 8, characterized in that: The amount of the flocculant added is 20 to 500 mg / L compared to the wastewater IV.

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