A high molecular resin denitration agent and a preparation method thereof

Abstract

The present application belongs to the field of flue gas denitration technology, in particular to a kind of high molecular resin denitration agent and its preparation method.Preparation method is first to catalyst and heat stabilizer impregnation, drying, calcination, then the surface of heat stabilizer containing catalyst is grafted with amine group silane coupling agent modification, then polymerization, urea or melamine or the mixture of urea and melamine is polymerized with formaldehyde into amine group high molecular resin, the thermal stability is improved, so it has better denitration performance;Add alkali metal promoter, it is beneficial to NO adsorption enrichment on the surface of high molecular resin denitration agent, further improve denitration performance.The high molecular resin denitration agent prepared by the method of the present application, the components include amine group high molecular resin, catalyst, heat stabilizer, alkali metal promoter, compared with urea and melamine, it has strong heat resistance, can well improve denitration performance, and the form of synthesized denitration agent is powder, which is convenient for gas transportation and storage.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of flue gas denitration, and particularly relates to a high-molecular resin denitration agent and a preparation method thereof. BACKGROUND

[0002] Nitrogen oxides are polluting gases generated in various industrial processes such as coal-fired power plants, waste incineration, cement plants, etc., which have a strong harm to the environment and human body. At present, the most commonly used method for controlling NOx is ammonia selective catalytic reduction (SCR); another is the use of ammonia, aqueous urea for selective non-catalytic reduction (SNCR). Although the SCR flue gas denitration technology has high denitration efficiency, it is not suitable for industries that produce flue gas with complex composition, such as waste incineration, etc., mainly because the flue gas contains a large amount of HCl, SO2 and other acidic gases and a large amount of Na, K and other dust. At the same time, the erosion of fly ash particles on the catalyst is more serious, and the impurity metal ions adsorbed on the surface of the catalyst lead to catalyst deactivation. The selective non-catalytic reduction (SNCR) denitration technology refers to the reduction of NOx in flue gas to N2 by ammonia and other reducing agents at high temperature. Its biggest advantage is that the cost is relatively low, but the efficiency of SNCR denitration is low, and at the same time, when ammonia is used as a reducing agent, the transportation and storage of liquid ammonia have high safety protection requirements, the denitration process of ammonia water and urea solution has high energy consumption, low efficiency, and ammonia leakage in the ammonia and urea process easily leads to secondary pollution problems. X

[0003] The PNCR denitration technology is a kind of technology that uses high-molecular denitration agent to decompose under high temperature (850-1200℃) to produce active ammonia and reducing groups, and the active ammonia and reducing groups react with NO in the flue gas to generate nitrogen, carbon dioxide, water and other substances that do not pollute the environment, thereby achieving the purpose of denitration. Therefore, the thermal decomposition performance of the denitration agent is crucial to the denitration performance, and the decomposition of urea at the nozzle is too fast under high temperature, which will lead to the decomposition of excessive ammonia gas, thereby causing the oxidation of unreacted ammonia gas to generate NO, low utilization rate of the denitration agent and poor denitration efficiency. The Chinese patent document with publication number CN 108187490A discloses a kind of high-molecular dry denitration agent, which only mixes the reducing agent including urea by simple grinding, and does not fundamentally solve the decomposition problem. The Chinese patent document with publication number CN 114272752A provides an organic coated denitration agent and a preparation method thereof, which performs surface modification on the surface of urea shaped particles in the form of a coating to form a polyurethane high-molecular film, improves the heat resistance, effectively slows down the invalid decomposition of urea at the denitration temperature, and improves the utilization rate of urea. However, this method does not improve the thermal decomposition performance of urea itself, and urea still decomposes at low temperature and diffuses out of the high-molecular film. SUMMARY

[0004] ​One of the purposes of the present application is to provide a preparation method of high molecular resin denitration agent, which has excellent heat resistance and high denitration efficiency, and good powder flowability, facilitating storage and transportation.

[0005] To achieve the above-mentioned purposes, the present application adopts the following technical solutions: a preparation method of high molecular resin denitration agent, comprising the following steps:

[0006] S1, adding 0.1-20 parts by mass of catalyst precursor to 50 parts by mass of water to prepare an aqueous solution, then adding 1-30 parts by mass of heat stabilizer for stirring, impregnation, drying, and calcining at 300-600℃, grinding the calcined product to obtain a solid powder;

[0007] S2, adding 1-10 parts by mass of amine-based silane coupling agent to an aqueous ethanol solution, pre-hydrolyzing, adding all the solid powder prepared in step S1, stirring at room temperature until the reaction is complete, centrifuging, washing and drying to obtain a heat stabilizer containing catalyst;

[0008] S3, adding 40-500 parts by mass of formaldehyde aqueous solution to a reaction kettle, the concentration of the formaldehyde aqueous solution being 10-50wt%, stirring and heating to a temperature of 40-95℃ and maintaining the temperature, then sequentially adding 30-90 parts by mass of melamine or urea, 1-10 parts by mass of surfactant and 1.1-50 parts by mass of heat stabilizer containing catalyst prepared in step S2, adjusting the pH value of the solution to 4-12, and reacting for 1.5-2h, then cooling, filtering and drying the reaction product to obtain a solid high molecular product containing amine-based high molecular resin;

[0009] Alternatively, 40-500 parts by mass of formaldehyde aqueous solution is added to a reaction kettle, the concentration of the formaldehyde aqueous solution being 10-50wt%, stirring and heating to a temperature of 60-95℃ and maintaining the temperature, then adding 30-90 parts by mass of melamine and 30-90 parts by mass of urea, then adding 1-5 parts by mass of 10wt% sodium hydroxide solution, stirring and reacting for 1.5-2h, then sequentially adding 1-10 parts by mass of surfactant and 1.1-50 parts by mass of heat stabilizer containing catalyst prepared in step S2, cooling to 40-50℃, adjusting the pH value of the solution to 4-12, then heating to 60-90℃, continuing to react for 1.5-2h, then cooling, filtering and drying the reaction product to obtain a solid high molecular product containing amine-based high molecular resin;

[0010] S4, taking 100 parts by mass of the solid high molecular product prepared in step S3, adding 1-20 parts by mass of alkali metal promoter, mixing and grinding to obtain the high molecular resin denitration agent.

[0011] Further improvement of the above-mentioned preparation method of high molecular resin denitration agent:

[0012] Preferably, the catalyst precursor is one or a combination of more than two of nitrate, acetate, oxalate, acetylacetone of iron, manganese, copper.

[0013] Preferably, the heat stabilizer is one or a combination of more than two of alumina, kaolin, attapulgite, montmorillonite, diatomite, bentonite.

[0014] Preferably, the amine-based silane coupling agent is one or a combination of more than two of KH-540, KH-550, KH-792.

[0015] Preferably, the surfactant is one or a combination of more than two of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium dodecyl sulfonate.

[0016] Preferably, the alkali metal promoter is one or several of sodium carbonate, sodium hydroxide, calcium hydroxide, calcium oxide, calcium carbonate, calcium acetylacetone.

[0017] Preferably, the amine-based high molecular resin is one or a combination of more than two of melamine-formaldehyde resin, melamine-formaldehyde-urea resin, urea-formaldehyde resin.

[0018] Preferably, the ethanol aqueous solution in step S2 is 30-50 parts by mass, and the concentration of the ethanol aqueous solution is 30-85wt%.

[0019] Preferably, the pH value of the formic acid solution added in step S3 is adjusted to 4-12.

[0020] The second object of the present application is to provide the high molecular resin denitration agent prepared by the preparation method.

[0021] The present application has the following advantages over the prior art:

[0022] 1) The present application provides a preparation method of a high molecular resin denitration agent, specifically comprising steps S1-S4, wherein in step S1, the catalyst is impregnated with a heat stabilizer, dried, and calcined, then in step S2, the surface of the heat stabilizer and the catalyst is grafted and modified with an amine silane coupling agent to obtain a heat stabilizer containing catalyst with a modified surface, which can improve its dispersibility in the resin and does not affect the polymerization of the resin. The added heat stabilizer can slow down the decomposition of the denitration agent at high temperatures and prevent the accumulation of the denitration agent at the nozzle of the spray gun. The added catalyst can improve the denitration efficiency; in step S3, urea or melamine or a mixture of urea and melamine is polymerized with formaldehyde into an amine-based high molecular resin, and the amine-based high molecular resin is one of melamine-formaldehyde high molecular resin, melamine-formaldehyde-urea high molecular resin, and urea-formaldehyde high molecular resin, or a combination of two or more thereof, which improves the thermal stability and thus has better denitration performance. The synthesized resin is in powder form, which is convenient for gas transportation and storage; in step S4, the addition of an alkali metal promoter is beneficial to the adsorption and enrichment of NO on the surface of the high molecular resin denitration agent, further improving the denitration performance.

[0023] 2) The high molecular resin denitration agent prepared by the method of the present application has components including an amine-based high molecular resin, a catalyst, a heat stabilizer, and an alkali metal promoter, which has stronger heat resistance than urea and melamine, can well improve the denitration performance, and the synthesized denitration agent is in powder form, which is convenient for gas transportation and storage. The denitration agent formula in the present application is simple and has low cost. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a high molecular resin denitration agent 1, 6 prepared by examples 1, 6 of the present application, and a thermal gravimetric comparison diagram of melamine and urea. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is further described in detail below with examples. All other examples obtained by those skilled in the art without creative labor based on the examples in the present application belong to the scope of protection of the present application.

[0026] Example 1

[0027] The present embodiment provides a preparation method of a high molecular resin denitration agent 1, specifically comprising the following steps:

[0028] S1, 20 parts by mass of ferric nitrate is added to 50 parts by mass of water to prepare an aqueous solution, then 10 parts by mass of kaolin is added for stirring, impregnation, drying, and then calcination at 400℃, after calcination, the solid powder is ground;

[0029] S2, 2 parts by mass of an amine-based silane coupling agent KH-550 is added to 30 parts by mass of an 80wt% ethanol aqueous solution, pre-hydrolyzed, and the entire solid powder prepared in step S1 is added, fully reacted under stirring at room temperature, washed with acetone after centrifugation, and dried to prepare a catalyst-containing thermal stabilizer;

[0030] S3, 140 parts by mass of a 10wt% formaldehyde aqueous solution is added to a reaction kettle, stirred and heated to a temperature of 80℃ and maintained at the temperature, and then 62 parts by mass of melamine, 4 parts by mass of a surfactant sodium dodecylbenzenesulfonate, and 10 parts by mass of the catalyst-containing thermal stabilizer prepared in step S2 are sequentially added, and finally formic acid is added to adjust the reaction pH to 4, and the reaction is performed for 1.5 hours, after which the reaction product is cooled, filtered, and dried to obtain a solid polymer product containing an amine-based polymer resin;

[0031] S4, 100 parts by mass of the solid polymer product containing the amine-based polymer resin prepared in step S3 is mixed with 10 parts by mass of calcium oxide, and the mixture is ground to obtain a polymer resin denitration agent 1.

[0032] Example 2

[0033] The present embodiment provides a preparation method of a polymer resin denitration agent 2, which specifically comprises the following steps:

[0034] S1, 0.1 parts by mass of copper acetylacetonate is added to 50 parts by mass of water to prepare an aqueous solution, and then 15 parts by mass of attapulgite is stirred, soaked, and dried, and then calcined at a high temperature of 500℃, and the calcined product is ground to obtain a solid powder;

[0035] S2, 5 parts by mass of an amine-based silane coupling agent KH-540 is added to 30 parts by mass of an 80wt% ethanol aqueous solution, pre-hydrolyzed, and the entire solid powder prepared in step S1 is added, fully reacted under stirring at room temperature, washed with acetone after centrifugation, and dried to prepare a catalyst-containing thermal stabilizer;

[0036] S3, 140 parts by mass of a 50wt% formaldehyde aqueous solution is added to a reaction kettle, stirred and heated to a temperature of 85℃ and maintained at the temperature, and then 78 parts by mass of melamine, 5 parts by mass of a surfactant sodium dodecylbenzenesulfonate, and 50 parts by mass of the catalyst-containing thermal stabilizer prepared in step S2 are sequentially added, and finally formic acid is added to adjust the reaction pH to 5, and the reaction is performed for 1.5 hours, after which the reaction product is cooled, filtered, and dried to obtain a solid polymer product containing an amine-based polymer resin;

[0037] S4, 100 parts by mass of the solid polymer product containing the amine-based polymer resin prepared in step S3 is mixed with 15 parts by mass of calcium hydroxide, and the mixture is ground to obtain a polymer resin denitration agent 2.

[0038] Example 3

[0039] The present embodiment provides a preparation method of the high molecular resin denitration agent 3, which specifically comprises the following steps:

[0040] S1, first, 17 parts by mass of iron acetate is added to 50 parts by mass of water to prepare an aqueous solution, then 30 parts by mass of montmorillonite is added for stirring, impregnation, drying, and then calcination at a high temperature of 600℃, and after calcination, the solid powder is prepared by grinding;

[0041] S2, 5 parts by mass of amine-based silane coupling agent KH-550 is added to 35 parts by mass of 50wt% aqueous ethanol solution, pre-hydrolyzed, and the entire solid powder prepared in step S1 is added, and the stirring reaction is fully carried out at room temperature, and after centrifugation, acetone washing and drying, the catalyst-containing thermal stabilizer is prepared;

[0042] S3, 262 parts by mass of 37wt% formaldehyde aqueous solution is added to a reaction kettle, stirred and heated to a temperature of 75℃ and kept at this temperature, then 75 parts by mass of urea and 38 parts by mass of melamine, 1 part by mass of 10wt% NaOH solution are added, and the stirring reaction is carried out for 1.5h, then 2 parts by mass of sodium dodecylbenzenesulfonate, 40 parts by mass of the catalyst-containing thermal stabilizer prepared in step S2 are sequentially added, the temperature is lowered to 50℃, formic acid is added to adjust the pH to 5.5, then the temperature is raised to 60℃, and the reaction is continued for 2h, and then the reaction product is filtered and dried to obtain a solid high molecular product containing amine-based high molecular resin;

[0043] S4, 100 parts by mass of the solid high molecular product containing amine-based high molecular resin prepared in step S3 is taken, mixed with 5 parts by mass of sodium hydroxide, and ground to obtain the high molecular resin denitration agent 3.

[0044] Example 4

[0045] The present embodiment provides a preparation method of the high molecular resin denitration agent 4, which specifically comprises the following steps:

[0046] S1, first, 1 part by mass of manganese nitrate is added to 50 parts by mass of water to prepare an aqueous solution, then 30 parts by mass of diatomite is added for stirring, impregnation, drying, and then calcination at a high temperature of 550℃, and after calcination, the solid powder is prepared by grinding;

[0047] S2, 4 parts by mass of amine-based silane coupling agent KH-550 is added to 40 parts by mass of 45wt% aqueous ethanol solution, pre-hydrolyzed, and the entire solid powder prepared in step S1 is added, and the stirring reaction is fully carried out at room temperature, and after centrifugation, acetone washing and drying, the catalyst-containing thermal stabilizer is prepared;

[0048] S3, 500 parts by mass of a 44 wt% formaldehyde aqueous solution is added to a reaction kettle, stirred and heated to a temperature of 85°C and the temperature is maintained, then 90 parts by mass of urea and 90 parts by mass of melamine, 2 parts by mass of a 10 wt% NaOH solution are added, stirred and reacted for 1.5 h, then 6 parts by mass of sodium dodecylbenzenesulfonate, 40 parts by mass of the catalyst-containing thermal stabilizer prepared in step S2 are sequentially added, cooled to 40°C, formic acid is added to adjust the pH to 5, then heated to 60°C, and reacted for 2 h, then cooled, the reaction product is filtered and dried to obtain a solid polymer product containing an amine group polymer resin;

[0049] S4, 100 parts by mass of the solid polymer product containing an amine group polymer resin prepared in step S3 is taken, mixed with 25 parts by mass of sodium carbonate, and ground to obtain a polymer resin denitration agent 4.

[0050] Example 5

[0051] The present embodiment provides a preparation method of a polymer resin denitration agent 5, which specifically comprises the following steps:

[0052] S1, first, 20 parts by mass of copper nitrate is added to 50 parts by mass of water to prepare an aqueous solution, then 25 parts by mass of bentonite is added for stirring, impregnation and drying, and then calcined at a high temperature of 600°C to obtain a solid powder;

[0053] S2, 10 parts by mass of an amine group silane coupling agent KH-792 is added to 35 parts by mass of a 70 wt% ethanol aqueous solution, pre-hydrolyzed, and then the entire solid powder prepared in step S1 is added for stirring and reaction at room temperature until sufficient reaction is achieved, then centrifuged, washed with acetone and dried to obtain a catalyst-containing thermal stabilizer;

[0054] S3, 303 parts by mass of a 25 wt% formaldehyde aqueous solution is added to a reaction kettle, stirred and heated to a temperature of 70°C and the temperature is maintained, then 85 parts by mass of urea, 5 parts by mass of sodium dodecylbenzenesulfonate, and 10 parts by mass of the catalyst-containing thermal stabilizer prepared in step S2 are sequentially added, formic acid is added to adjust the pH to 5, and reacted for 2 h, then cooled to room temperature and placed in a drying oven for drying to obtain a solid polymer product containing an amine group polymer resin;

[0055] S4, 100 parts by mass of the solid polymer product containing an amine group polymer resin prepared in step S3 is taken, mixed with 5 parts by mass of calcium acetylacetonate, and ground to obtain a polymer resin denitration agent 5.

[0056] Example 6

[0057] The present embodiment provides a preparation method of a polymer resin denitration agent 6, which specifically comprises the following steps:

[0058] S1, 9 parts by mass of manganese acetate is first added to 50 parts by mass of water to prepare an aqueous solution, then 30 parts by mass of kaolin is added to stir, impregnate, dry, and then calcined at 450°C, after calcination, the solid powder is prepared by grinding;

[0059] S2, 8 parts by mass of amine silane coupling agent KH-540 is added to 35 parts by mass of 85wt% aqueous ethanol solution, pre-hydrolyzed, and then the entire solid powder prepared in step S1 is added, stirred at room temperature for 20h, after centrifugation, washed with acetone and dried to obtain a heat stabilizer containing catalyst;

[0060] S3, 262 parts by mass of 30wt% formaldehyde aqueous solution is added to a reaction kettle, stirred and heated to a temperature of 85°C and maintained at this temperature, then 89 parts by mass of urea, 4 parts by mass of sodium dodecyl benzene sulfonate, 5 parts by mass of heat stabilizer containing catalyst prepared in step S2 is added, formic acid is added to adjust the pH to 5.5, and after 1.5h of reaction, the reaction product is cooled, filtered and dried to obtain a solid polymer product containing amine-based high molecular resin;

[0061] S4, 100 parts by mass of the solid polymer product prepared in step S3 is mixed with 20 parts by mass of calcium hydroxide, ground to obtain a high molecular resin denitration agent 6.

[0062] Figure 1 is a thermogravimetric comparison diagram of the high molecular resin denitration agent 1, 6 prepared in examples 1, 6 of the present application and single melamine, urea. Figure 1 It can be seen that the high molecular formed by cross-linking after polymerization has significantly improved heat resistance.

[0063] Comparative Example 1

[0064] Comparative Example 1 is a melamine-formaldehyde resin, and its preparation method is referred to Example 2, except that "50 parts by mass of heat stabilizer containing catalyst prepared in step S2" is not added in step S3, and finally a melamine-formaldehyde resin is prepared.

[0065] Comparative Example 2

[0066] Comparative Example 2 is a melamine-urea-formaldehyde resin, and its preparation method is referred to Example 3, except that "40 parts by mass of heat stabilizer containing catalyst prepared in step S2" is not added in step S3, and finally a melamine-urea-formaldehyde resin is prepared.

[0067] Comparative Example 3

[0068] Comparative Example 2 is a urea-formaldehyde resin, and its preparation method is referred to Example 5, except that "10 parts by mass of heat stabilizer containing catalyst prepared in step S2" is not added in step S3, and finally a urea-formaldehyde resin is prepared.

[0069] The denitration performance of the denitration agent was evaluated by a denitration performance evaluation device composed of a fixed bed reaction device and an online analysis device. The denitration agent was subjected to the denitration performance evaluation of Examples 1-6 at 800-900℃. Table 1 shows the denitration rates of Examples 1-6 at a NO concentration of 500ppm at different temperatures.

[0070] Table 1 shows the denitration performance of different amine-based polymer resin denitration agents

[0071]

[0072] As shown in Table 1, when urea and melamine are directly used as denitration agents without any treatment, the denitration rates are only 45% and 32%, respectively. However, the denitration rates of the polymer resin denitration agents synthesized according to the present application are all above 90%.

[0073] Comparative Example 1, Comparative Example 2 and Comparative Example 3 are polymer resin denitration agents without any additives, and their denitration rates are all below 90%.

[0074] By Figure 1 As shown in the thermogravimetric characterization, the weight loss temperature of Example 1 (370℃) is significantly increased compared with that of melamine (300℃), and the weight loss temperature of Example 6 (300℃) is also significantly increased compared with that of urea (210℃). Accordingly, the denitration rates of Examples 1 and 6 are both significantly increased compared with those of melamine and urea.

[0075] The above is only the preferred embodiments of the present application, and does not limit the patent scope of the present application. For those skilled in the art, the present application can have various modifications and changes. As long as the changes and modifications of the above-described embodiments are within the spirit and scope of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A method for preparing a polymeric resin denitrifying agent, characterized in that, Includes the following steps: S1. Add 0.1-20 parts by weight of catalyst precursor to 50 parts by weight of water to prepare an aqueous solution, then add 1-30 parts by weight of heat stabilizer, stir, impregnate, dry, and then calcine at 300-600℃. After calcination, grind to obtain solid powder. S2. Add 1-10 parts by weight of aminosilane coupling agent to an aqueous ethanol solution, pre-hydrolyze, add all the solid powder obtained in step S1, stir the reaction at room temperature until it is fully reacted, centrifuge, wash and dry to obtain a heat stabilizer containing catalyst. S3. Add 40-500 parts by weight of formaldehyde aqueous solution to the reaction vessel. The concentration of the formaldehyde aqueous solution is 10-50 wt%. Stir and heat to a temperature of 40-95℃ and maintain this temperature. Then add 30-90 parts by weight of melamine or urea, 1-10 parts by weight of surfactant and 1.1-50 parts by weight of the heat stabilizer containing catalyst prepared in step S2 in sequence. Adjust the pH of the solution to 4-12. After reacting for 1.5-2 hours, cool. Filter and dry the reaction product to obtain a solid polymer product containing amine-based polymer resin. Alternatively, 40-500 parts by weight of a formaldehyde aqueous solution with a concentration of 10-50 wt% are added to a reaction vessel, stirred and heated to 60-95°C and maintained at that temperature. 30-90 parts by weight of melamine and 30-90 parts by weight of urea are added, followed by 1-5 parts by weight of a 10 wt% sodium hydroxide solution. The mixture is stirred and reacted for 1.5-2 hours. Then, 1-10 parts by weight of a surfactant and 1.1-50 parts by weight of the catalyst-containing heat stabilizer prepared in step S2 are added sequentially. The temperature is lowered to 40-50°C, the pH of the solution is adjusted to 4-12, and the temperature is raised to 60-90°C. The reaction is continued for 1.5-2 hours and then cooled. The reaction product is filtered and dried to obtain a solid polymer product containing an amino-based polymer resin. S4. Take 100 parts by weight of the solid polymer product obtained in step S3, add 1-20 parts by weight of alkali metal accelerator, mix and grind to obtain polymer resin denitrification agent.

2. The preparation method of the polymer resin denitrifying agent according to claim 1, characterized in that, The catalyst precursor is one or a combination of two or more of the following: nitrates, acetates, oxalates, and acetylacetones of iron, manganese, and copper.

3. The method for preparing the polymer resin denitrifying agent according to claim 1 or 2, characterized in that, The heat stabilizer is one or a combination of two or more of the following: alumina, kaolin, attapulgite, montmorillonite, diatomaceous earth, and bentonite.

4. The preparation method of the polymer resin denitrifying agent according to claim 1, characterized in that, The aminosilane coupling agent is one or a combination of two or more of KH-540, KH-550, and KH-792.

5. The preparation method of the polymer resin denitrifying agent according to claim 1, characterized in that, The surfactant is one or a combination of two or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium dodecyl sulfonate.

6. The method for preparing the polymer resin denitrifying agent according to claim 1, characterized in that, The alkali metal accelerator is one or more of sodium carbonate, sodium hydroxide, calcium hydroxide, calcium oxide, calcium carbonate, and calcium acetylacetonate.

7. The preparation method of the polymer resin denitrifying agent according to claim 1, characterized in that, The amine-based polymer resin is one or a combination of two or more of melamine-formaldehyde resin, melamine-formaldehyde-urea resin, and urea-formaldehyde resin.

8. The method for preparing the polymer resin denitrifying agent according to claim 1, characterized in that, The ethanol-water solution mentioned in step S2 is 30-50 parts by mass, and the concentration of the ethanol-water solution is 30-85 wt%.

9. The method for preparing the polymer resin denitrifying agent according to claim 1, characterized in that, In step S3, formic acid is used to adjust the pH of the solution to 4-12.

10. A polymeric resin denitrifying agent prepared by any one of claims 1-9.

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