A high-molecular polymer denitration agent, a preparation method and application thereof
The high-molecular polymer denitrification agent, which is a compound of amino polymer and urea, solves the problems of low denitrification efficiency, high equipment requirements and narrow temperature window in the existing technology, and achieves efficient and safe denitrification effect, which is suitable for industrial flue gas treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG LEER ENVIRONMENTAL TECH CO LTD
- Filing Date
- 2026-04-27
- Publication Date
- 2026-07-28
AI Technical Summary
Existing denitrification technologies such as SCR and SNCR have problems such as high cost, high equipment requirements, poor spray dispersion, and narrow temperature window. Traditional powder form denitrification agents require pneumatic conveying, and urea solutions have poor activity in the low temperature range, resulting in low denitrification efficiency.
A polymeric denitrification agent, an aqueous solution of amino polymer and urea, is used. By atomizing and spraying the solution into flue gas at 550–950°C, the synergistic effect of the amino polymer and urea is utilized to broaden the temperature window and improve the denitrification efficiency.
It achieves efficient denitrification with a denitrification rate of over 85%, has a wide temperature window, good equipment compatibility, low cost, and safe raw materials with no secondary pollution, making it suitable for industrial production.
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Figure CN122461889A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of flue gas denitrification technology, specifically relating to a polymeric denitrification agent, its preparation method, and its application. Background Technology
[0002] Nitrogen oxides (NO) x NO is a major air pollutant generated during the industrial processes of waste incineration plants. x When exposed to sunlight, it undergoes a photochemical reaction with volatile organic compounds (VOCs) to generate secondary pollutants such as ground-level ozone and peroxyacetyl nitrate, resulting in photochemical smog, which reduces air quality and visibility and poses a significant threat to the environment and human health.
[0003] Currently, the mainstream denitrification technologies are selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR). SCR has high denitrification efficiency, but requires a catalyst, is easily deactivated by impurities in flue gas, and has high investment and operating costs. SNCR does not require a catalyst and has lower costs, but suffers from problems such as insufficient decomposition of the reducing agent, low denitrification efficiency, and a narrow reaction temperature window. Existing PNCR polymeric denitrification agents are mostly in powder form, requiring a pneumatic conveying system, which places high demands on equipment and results in poor spray dispersion. Traditional urea and ammonia aqueous solutions have narrow temperature windows, and it is difficult to effectively decompose and generate active ammonia in the low-temperature range, thus limiting the denitrification effect.
[0004] Therefore, developing a new type of denitrification agent that is liquid, has a wide temperature window, high efficiency, and is easy to use has significant engineering value. Summary of the Invention
[0005] Purpose of the invention: The purpose of this invention is to overcome the shortcomings of the prior art and provide a polymeric denitrification agent, its preparation method, and its application.
[0006] Technical solution: A polymeric denitrification agent, which is an aqueous solution of an amino polymer and urea, comprising, by weight: 1-30 parts of amino polymer 10-60 parts of urea 30-80 parts water Additives: 0-5 parts.
[0007] A further improvement of the present invention is that the amino polymer is selected from at least one of polyacrylamide, polymethacrylamide, polyacrylate, polymethacrylate, acrylamide-acrylate copolymer and blends thereof.
[0008] A further improvement of the present invention is that the weight-average molecular weight of the amino polymer is 1,000 to 500,000.
[0009] A further improvement of the present invention is that the amino polymer is prepared by polymerizing an amino-rich organic monomer at 50–90°C for 30–420 minutes in the presence of an initiator and a crosslinking agent, followed by drying and pulverization.
[0010] A further improvement of the present invention is that the amino-rich organic monomer is selected from one or more of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, potassium 2-acrylamido-2-methylpropanesulfonate, sodium 2-acrylamido-2-methylpropanesulfonate, and ammonium 2-acrylamido-2-methylpropanesulfonate.
[0011] A further improvement of the present invention is that the additive is selected from one or more of ammonium stearate, magnesium stearate, calcium stearate, antifungal agent, precipitated calcium carbonate, magnesium oxide, and zeolite.
[0012] A method for preparing a polymeric denitrification agent, comprising the following steps: S1. Weigh out the amino polymer, urea, water, and additives according to the specified ratio; S2. Heat water to 40-80℃, add urea while stirring, and dissolve to obtain a urea aqueous solution; S3. Slowly add the amino polymer to the urea aqueous solution and stir continuously until completely dissolved to obtain a homogeneous solution; S4. Add any optional additives, stir well, and you have the product.
[0013] A further improvement of the present invention is that, in step S3, the stirring rate is 200-800 rpm and the stirring time is 10-60 minutes.
[0014] A further improvement of the present invention is that, in step S3, the temperature when adding the amino polymer is controlled at 50–70°C.
[0015] An application of a polymeric denitrification agent involves spraying the denitrification agent in the form of an atomized spray into flue gas at a temperature of 550–950°C, where it reacts with nitrogen oxides to generate nitrogen and water. The denitrification temperature window is broadened through the synergistic effect of the amino polymer and urea.
[0016] Compared with the prior art, the polymeric denitrification agent, its preparation method, and its application provided by the present invention achieve at least the following beneficial effects: (1) High denitrification efficiency: The denitrification rate can reach more than 85% in the range of 550 to 850℃; (2) It has a wide temperature window and can maintain high activity in the medium and low temperature range; (3) It is in the form of an aqueous solution, which can be directly atomized and sprayed without the need for pneumatic conveying, and has good equipment compatibility; (4) The preparation process is simple, the conditions are mild, and the energy consumption is low, making it suitable for industrial production; (5) The raw materials are low in toxicity and the reaction products are clean, with no secondary pollution. Attached Figure Description
[0017] Figure 1 Flowchart of the preparation process of polymeric denitrification agent; Figure 2 This is a process flow diagram for the application of polymeric denitrification agents; Figure 3 This is a curve comparing the denitrification efficiency of the present invention with that of traditional urea solution.
[0018] Explanation of reference numerals in the attached figures: 1-Concentrate tank; 2-Agitator; 3-Transfer pump; 4-Dilution mixing tank; 5-Flue; 6-Spray gun. Detailed Implementation
[0019] Various exemplary embodiments of the present invention will now be described in detail. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values of the components and steps set forth in these embodiments do not limit the scope of the invention. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.
[0020] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.
[0021] See Figure 1-3 A polymeric denitrification agent, comprising an aqueous solution of an amino polymer and urea, in parts by weight: 1-30 parts of amino polymer 10-60 parts of urea 30-80 parts water Additives: 0-5 parts.
[0022] The amino polymer is selected from at least one of polyacrylamide, polymethacrylamide, polyacrylate, polymethacrylate, acrylamide-acrylate copolymer and their blends; the weight average molecular weight of the amino polymer is 1,000 to 500,000; the amino polymer is obtained by polymerizing amino-rich organic monomers in the presence of an initiator and a crosslinking agent at 50 to 90°C for 30 to 420 minutes, followed by drying and pulverization.
[0023] The amino-rich organic monomer is selected from one or more of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, potassium 2-acrylamido-2-methylpropanesulfonate, sodium 2-acrylamido-2-methylpropanesulfonate, and ammonium 2-acrylamido-2-methylpropanesulfonate.
[0024] The additives are selected from one or more of the following: ammonium stearate, magnesium stearate, calcium stearate, antifungal agents, precipitated calcium carbonate, magnesium oxide, and zeolite.
[0025] A method for preparing a polymeric denitrification agent, comprising the following steps: S1. Weigh out the amino polymer, urea, water, and additives according to the specified ratio; S2. Heat water to 40-80℃, add urea while stirring, and dissolve to obtain a urea aqueous solution; S3. Slowly add the amino polymer to the urea aqueous solution and stir continuously until completely dissolved to obtain a homogeneous solution; S4. Add any optional additives, stir well, and you have the product.
[0026] In step S3, the stirring speed is 200-800 rpm and the stirring time is 10-60 minutes; in step S3, the temperature when adding the amino polymer is controlled at 50-70℃.
[0027] The denitrification agent is sprayed into the flue gas at a temperature of 550–950°C in the form of atomization, and reacts with nitrogen oxides to generate nitrogen and water. The denitrification temperature window is widened through the synergistic effect of amino polymer and urea.
[0028] An application of a polymeric denitrification agent involves spraying the denitrification agent in the form of an atomized spray into flue gas at a temperature of 550–950°C, where it reacts with nitrogen oxides to generate nitrogen and water. The denitrification temperature window is broadened and the denitrification efficiency is improved through the synergistic effect of the amino polymer and urea.
[0029] Example 1 Preparation of amino polymers Add 500 parts of distilled water to the reaction vessel, add 100 parts of acrylamide under ice bath conditions, stir well, and then add 1.5 parts of ammonium persulfate and 0.8 parts of N,N′-methylenebisacrylamide. Heat to 60℃, stir and react for 240 minutes, cool, dry and pulverize to obtain polyacrylamide with a weight average molecular weight of approximately 150,000.
[0030] Example 2 Preparation of amino polymers Add 600 parts of distilled water to the reactor, and under ice bath conditions, add 60 parts of acrylamide and 40 parts of 2-acrylamido-2-methylpropanesulfonic acid. After stirring, add 2.0 parts of ammonium persulfate and 1.0 part of N,N′-methylenebisacrylamide. Heat to 70°C and react for 300 minutes. Cool, dry, and pulverize to obtain a copolymer with a molecular weight of approximately 200,000.
[0031] Example 3 By weight: 15 parts amino polymer (Example 1), 35 parts urea, 48 parts water, and 2 parts calcium stearate. The urea was dissolved in water at 60°C. The polymer was added, and the mixture was stirred at 500 rpm for 30 minutes. Additives were then added and stirred until homogeneous to obtain the denitrifying agent.
[0032] Example 4 By weight: 20 parts amino polymer (Example 2), 40 parts urea, 38 parts water, and 2 parts magnesium oxide. Dissolve the urea in water at 65°C, add the polymer, stir at 600 rpm for 40 minutes, and then add the additives and stir until homogeneous.
[0033] Example 5 By weight: 10 parts amino polymer (Example 1), 30 parts urea, 58 parts water, and 2 parts zeolite. Dissolve the urea in water at 55°C, add the polymer, stir at 400 rpm for 25 minutes, and then add the additives and stir until homogeneous.
[0034] Comparative Example 1 Dissolve 35 parts urea and 65 parts water by stirring at room temperature to obtain a traditional urea solution.
[0035] practicality The raw materials of this invention are readily available, the preparation process is simple, the operation is mild, and the product is a liquid, which can be directly modified from existing SNCR spraying systems.
[0036] Performance testing Simulated flue gas: flow rate 1000 Nm³ / h, NO x The initial concentration was 350 mg / Nm³, the O2 content was 6%, and the ammonia-nitrogen molar ratio was 1.2:1.
[0037] The comparison table is as follows:
[0038] The results show that the denitrification agent of the present invention has significantly higher efficiency than traditional urea solution in the temperature range of 650-1050℃, with a wider effective temperature window and better low-temperature performance.
[0039] Application Examples Application in a 35 t / h coal-fired chain grate boiler, flue gas temperature 620~680℃, NO xInitial concentration: 320–380 mg / Nm³. Using the denitrification agent from Example 4, the agent was atomized and injected into the flue. After stable operation, the NO at the outlet... x With a concentration of 38–45 mg / Nm³, the denitrification efficiency is 86%–89%, ammonia slip is <3 ppm, and the operating cost is reduced by about 40% compared to SCR.
[0040] In summary, this invention is based on the SNCR denitrification principle, where urea decomposes at high temperatures to produce active components such as NH3 and HNCO; the amino polymer is rich in -NH2 functional groups, which continuously release active ammonia and reducing groups at high temperatures, forming a synergistic effect with urea, thereby improving low-temperature reactivity, widening the effective temperature range, and enhancing denitrification efficiency.
[0041] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.
Claims
1. A polymeric denitrification agent, characterized in that, An aqueous solution of amino polymer and urea, comprising, by weight: 1-30 parts of amino polymer 10-60 parts of urea 30-80 parts water Additives: 0-5 parts.
2. The polymeric denitrification agent according to claim 1, characterized in that, The amino polymer is selected from at least one of polyacrylamide, polymethacrylamide, polyacrylate, polymethacrylate, acrylamide-acrylate copolymer and blends thereof.
3. The polymeric denitrification agent according to claim 2, characterized in that, The weight-average molecular weight of the amino polymer is 1,000 to 500,000.
4. The polymeric denitrifying agent according to claim 1, characterized in that, The amino polymer is prepared by polymerizing amino-rich organic monomers at 50–90°C for 30–420 minutes in the presence of an initiator and a crosslinking agent, followed by drying and pulverization.
5. The polymeric denitrifying agent according to claim 4, characterized in that, The amino-rich organic monomer is selected from one or more of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, potassium 2-acrylamido-2-methylpropanesulfonate, sodium 2-acrylamido-2-methylpropanesulfonate, and ammonium 2-acrylamido-2-methylpropanesulfonate.
6. The polymeric denitrification agent according to claim 1, characterized in that, The additives are selected from one or more of the following: ammonium stearate, magnesium stearate, calcium stearate, antifungal agents, precipitated calcium carbonate, magnesium oxide, and zeolite.
7. A method for preparing a polymeric denitrification agent, characterized in that: The application of the polymeric denitrification agent according to any one of claims 1 to 6 includes the following specific steps: S1. Weigh out the amino polymer, urea, water, and additives according to the specified ratio; S2. Heat water to 40-80℃, add urea while stirring, and dissolve to obtain a urea aqueous solution; S3. Slowly add the amino polymer to the urea aqueous solution and stir continuously until completely dissolved to obtain a homogeneous solution; S4. Add any optional additives, stir well, and you have the product.
8. The method for preparing a polymeric denitrifying agent according to claim 7, characterized in that, In step S3, the stirring rate is 200-800 rpm and the stirring time is 10-60 minutes.
9. The method for preparing a polymeric denitrifying agent according to claim 7, characterized in that, In step S3, the temperature during the addition of the amino polymer is controlled at 50–70°C.
10. The application of a polymeric denitrifying agent as described in any one of claims 1 to 6, characterized in that, The denitrification agent is sprayed into the flue gas at a temperature of 550–950°C in the form of atomization, and reacts with nitrogen oxides to generate nitrogen and water. The denitrification temperature window is widened through the synergistic effect of amino polymer and urea.