Melamine particles and preparation method thereof

Abstract

The invention discloses melamine particles and a preparation method thereof, and the melamine particles comprise the following components in percentage by mass: 55%-65% of melamine resin particles, 12%-18% of copper oxide (CuO), 8%-12% of cerium oxide (CeO2), 4%-6% of manganese oxide (MnO2), 4%-6% of aluminum oxide (Al2O3), 2%-4% of silicon oxide (SiO2) and 1%-3% of graphene nanosheets. The problems that the denitration and demercuration efficiency of the catalyst is reduced and strict requirements of a flue gas treatment system of a coal-fired power plant on the catalyst cannot be effectively met due to the fact that the dispersity of the catalyst and the utilization rate of active components are low when melamine resin particles are used as a catalyst carrier are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of polymers, and in particular relates to melamine particles and a preparation method thereof. Background Art

[0002] In the flue gas treatment process of coal-fired power plants, nitrogen oxides (NOx) and mercury (Hg) are two major air pollutants. In order to effectively control the emission of these pollutants, coal-fired power plants usually adopt a series of technical means, among which denitrification catalysts and demercuration catalysts are indispensable key parts. Melamine resin particles are expected to become a new catalyst carrier or active component in this field due to their good adsorption performance, chemical stability and adjustable surface properties.

[0003] Specifically, melamine resin particles can be modified to introduce metal ions or compounds with catalytic activity, thereby preparing catalysts with high efficiency in denitrification and demercuration. These catalysts can effectively convert NOx and Hg in flue gas into harmless or low-toxic substances in the flue gas treatment system of coal-fired power plants, thereby achieving the purpose of reducing air pollution.

[0004] In addition, when melamine resin particles are used as catalyst carriers, their large specific surface area and rich pore structure help improve the dispersion of the catalyst and the utilization rate of active components, thereby further improving the denitration and demercuration efficiency of the catalyst. At the same time, melamine resin particles also have good thermal stability and mechanical strength, which can meet the stringent requirements of the flue gas treatment system of coal-fired power plants for catalysts. However, when melamine resin particles are used as catalyst carriers, the dispersion of the catalyst and the utilization rate of active components are low, thereby reducing the denitration and demercuration efficiency of the catalyst, and cannot effectively meet the stringent requirements of the flue gas treatment system of coal-fired power plants for catalysts. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot 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 object of the present invention is to overcome the deficiencies in the prior art and provide a melamine particle.

[0008] To solve the above technical problems, the present invention provides the following technical solution: a melamine particle, characterized in that the melamine particle comprises the following raw materials in mass fractions: 55% to 65% melamine resin particles, 12% to 18% copper oxide, 8% to 12% cerium oxide, 4% to 6% manganese oxide, 4% to 6% aluminum oxide, 2% to 4% silicon oxide, and 1% to 3% graphene nanosheets.

[0009] Another object of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing melamine particles, which is characterized by comprising:

[0010] Pretreatment: Wash the melamine resin particles with cleaning solution and deionized water, and dry them for later use;

[0011] Preparing a solution: preparing a mixed solution of copper oxide, cerium oxide, manganese oxide, aluminum oxide and silicon oxide, and adjusting the pH to 4 to 6;

[0012] Impregnation: Add the pretreated melamine resin particles into the mixed solution, stir at a constant speed, and impregnate for 30 minutes;

[0013] Precipitation attachment: uniformly add alkaline solution until pH = 7, stirring continuously during the addition process;

[0014] Aging treatment: Aging the mixed solution after precipitation attachment for 24 to 48 hours;

[0015] Washing and drying: washing the particles with deionized water, ultrasonically cleaning and drying to obtain the melamine particles.

[0016] As a preferred solution of the preparation method of the present invention, the cleaning solution is an ethanol solution with a concentration of 70% to 95%.

[0017] As a preferred embodiment of the preparation method of the present invention, the drying temperature of the pretreatment is 80° C. and the drying time is 2 h.

[0018] As a preferred embodiment of the preparation method of the present invention, the uniform stirring comprises a stirring rate of 100 to 200 r / min.

[0019] As a preferred embodiment of the preparation method of the present invention, the alkaline solution in the precipitation attachment is a sodium hydroxide solution.

[0020] As a preferred embodiment of the preparation method of the present invention, the aging treatment is to age the mixed solution at 40-60° C. so that the precipitate forms a stable coating on the particle surface.

[0021] As a preferred embodiment of the preparation method of the present invention, the ultrasonic cleaning is performed for 30 minutes and 3 times.

[0022] Another object of the present invention is to overcome the deficiencies in the prior art and provide an application of melamine particles in the flue gas treatment process of a coal-fired power plant, using the melamine particles prepared by any preparation method described in claims 2 to 7 as fillers to filter and adsorb the flue gas of the coal-fired power plant.

[0023] As a preferred embodiment of the application of the present invention, the melamine particles are used as catalyst carriers, and the copper oxide, cerium oxide, manganese oxide, aluminum oxide and silicon oxide attached to the melamine particles can convert NOx and Hg in the flue gas into harmless or low-toxic substances.

[0024] Beneficial effects of the present invention:

[0025] (1) Copper oxide (CuO) is a common active component of denitrification catalysts and can effectively promote the reduction reaction of NOx; cerium oxide (CeO2) not only has denitrification activity, but also can enhance the catalyst's resistance to sulfur poisoning. At the same time, it has a strong interaction with mercury, which helps to oxidize and capture mercury; manganese oxide (MnO2) as an auxiliary active component can further enhance the denitrification and demercurization performance of the catalyst.

[0026] (2) Alumina (Al2O3) as a carrier additive can improve the mechanical strength and thermal stability of the catalyst, while improving the dispersibility of the active components; silicon oxide (SiO2) also acts as a carrier additive, which helps to adjust the pore structure and specific surface area of ​​the catalyst, further improving the performance of the catalyst.

[0027] (3) Graphene nanosheets, as conductive and dispersing agents, can enhance the conductivity of catalysts and the dispersion of active components, promoting electron transfer and catalytic reactions.

[0028] (4) Melamine resin particles: Use high-purity, high-specific-surface-area melamine resin particles to ensure that the catalyst has good physical structure and chemical stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing 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 creative labor. Among them:

[0030] Figure 1 The present invention is a schematic diagram of the preparation process of the embodiment. DETAILED DESCRIPTION

[0031] 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.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and 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.

[0033] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0034] The raw materials used in the present invention are as follows: melamine resin particles are 3089-11-0 melamine resin particles produced by Kunshan Aichao Biotechnology Co., Ltd., copper oxide (CuO) is 1317-38-0 produced by Yinbaihe Metal Materials Co., Ltd., cerium oxide (CeO2) is 0088 produced by Qinghe Chaotai Metal Materials Co., Ltd., manganese oxide (MnO2) is 1300-3-5 produced by Qinghe Chaotai Metal Materials Co., Ltd., aluminum oxide (Al2O3) is JC-A30P produced by Qinghe Chaotai Metal Materials Co., Ltd., silicon oxide (SiO2) is 1349-44-3 produced by Qinghe Chaotai Metal Materials Co., Ltd., and graphene nanosheets are 7782-42-5 produced by Zhongke Leiming (Beijing) Technology Co., Ltd.

[0035] Example 1

[0036] This embodiment provides a method for preparing melamine particles. The raw materials of the melamine particles in this embodiment include: 55% melamine resin particles, 18% copper oxide (CuO), 8% cerium oxide (CeO2), 6% manganese oxide (MnO2), 6% aluminum oxide (Al2O3), 4% silicon oxide (SiO2), and 3% graphene nanosheets. The specific preparation steps are as follows:

[0037] (1) Pretreatment of melamine resin particles: ethanol solution was used as the cleaning solution, and ultrasonic cleaning equipment was used for cleaning 3 times, each time for 30 minutes, to remove impurities and oil stains on the surface. After cleaning, the melamine resin particles were rinsed with deionized water, and the cleaned melamine resin particles were dried at 80° C. using hot air drying for 2 hours;

[0038] (2) Preparing a solution: According to the weight of the melamine resin, respectively prepare solutions containing corresponding mass fractions of copper oxide, cerium oxide, manganese oxide, aluminum oxide and silicon oxide, and adjust the pH value thereof to 4-6; (the copper oxide solution is a copper sulfate solution, the cerium oxide solution is a cerium nitrate solution, the manganese oxide solution is a manganese sulfate solution, the aluminum oxide solution is an aluminum sulfate solution, and the silicon oxide solution is a sodium silicate solution.)

[0039] (3) Impregnation: Mix the solutions prepared in (2), add the pretreated melamine resin particles into the mixed solution, and stir at a constant speed for 30 minutes to fully immerse the particles in the mixed solution;

[0040] (4) Precipitation and attachment: sodium hydroxide solution is added dropwise at a uniform rate to obtain uniform and fine precipitated particles, so that the active component and the auxiliary component are completely co-precipitated and attached to the surface of the melamine resin particles (the concentration of the sodium hydroxide solution is 0.1 M, and a peristaltic pump is used for dropwise addition, and a magnetic stirrer is used for continuous stirring during the dropwise addition process. The dropwise addition speed is 2 drops per second, and the pH value of the mixed solution is continuously detected during the dropwise addition process until the pH value of the mixed solution is 7 and the dropwise addition is stopped);

[0041] (5) Aging treatment: aging the mixed solution at a temperature of 40° C. to 60° C. for 24 to 48 hours to allow the precipitate to form a stable coating on the particle surface;

[0042] (6) Particle washing: The particles were washed with deionized water and then cleaned with an ultrasonic cleaning device three times for 30 minutes each time to remove unattached precipitates and impurities;

[0043] (7) Drying: The washed particles were dried at 80°C for 2 h.

[0044] Example 2

[0045] The difference between this embodiment and embodiment 1 is that the raw materials of melamine particles are replaced with 60% melamine resin particles, 15% copper oxide (CuO), 10% cerium oxide (CeO2), 5% manganese oxide (MnO2), 5% aluminum oxide (Al2O3), 3% silicon oxide (SiO2), and 2% graphene nanosheets, and the remaining steps are the same as in embodiment 1 to obtain melamine particles.

[0046] Example 3

[0047] The difference between this embodiment and embodiment 1 is that the raw materials of melamine particles are replaced by 65% ​​melamine resin particles, 12% copper oxide (CuO), 12% cerium oxide (CeO2), 4% manganese oxide (MnO2), 4% aluminum oxide (Al2O3), 2% silicon oxide (SiO2), and 1% graphene nanosheets, and the remaining steps are the same as in embodiment 1 to obtain melamine particles.

[0048] The melamine particles prepared in Examples 1 to 3 are used as fillers to filter and adsorb the flue gas of a coal-fired power plant. Specifically, the prepared melamine particles are mixed in a certain proportion and filled into the filter. The filter is designed as a multi-layer structure, and each layer is filled with melamine particles to ensure that the flue gas can fully contact the melamine particles when passing through. The size and shape of the filter are designed according to the needs of the actual flue gas treatment system to ensure that it can be installed in the existing flue gas treatment pipeline. The flue gas of the coal-fired power plant passes through the pretreatment system to remove most of the particulate matter and some harmful gases, and then enters the filter filled with melamine particles. In the filter, harmful gases in the flue gas, such as nitrogen oxides (NOx) and mercury (Hg), react chemically with the active components on the surface of the melamine particles and are effectively adsorbed and converted. The results are shown in Table 1.

[0049] Table 1

[0050] Experimental samples Out of stock rate (%) Mercury removal rate (%) Example 1 98 98 Example 2 98.1 97.5 Example 3 97.6 97.9

[0051] Comparative Example 1

[0052] The difference between this embodiment and embodiment 1 is that the raw materials of melamine particles are replaced with 60% melamine resin particles, 15% copper oxide (CuO), 10% cerium oxide (CeO2), 5% manganese oxide (MnO2), 5% aluminum oxide (Al2O3), 2% carbon black (C7H4O2), and 3% silicon oxide (SiO2), and the remaining steps are the same as in embodiment 1 to obtain melamine particles.

[0053] Comparative Example 2

[0054] The difference between this embodiment and embodiment 1 is that the raw materials of melamine particles are replaced with 55% melamine resin particles, 18% copper oxide (CuO), 8% cerium oxide (CeO2), 6% manganese oxide (MnO2), 6% aluminum oxide (Al2O3), 3% graphene nanosheets, and 4% activated carbon, and the remaining steps are the same as in embodiment 1 to obtain melamine particles.

[0055] Comparative Example 3

[0056] The difference between this embodiment and embodiment 1 is that the raw materials of melamine particles are replaced with 55% melamine resin particles, 18% copper oxide (CuO), 8% cerium oxide (CeO2), 6% manganese oxide (MnO2), 6% aluminum oxide (Al2O3), 4% carbon black (C7H4O2), and 3% activated carbon, and the remaining steps are the same as in embodiment 1 to obtain melamine particles.

[0057] The melamine particles prepared in Example 1 and Comparative Examples 1 to 3 are used as fillers to filter and adsorb the flue gas of a coal-fired power plant. Specifically, the prepared melamine particles are mixed in a certain proportion and filled into the filter. The filter is designed as a multi-layer structure, and each layer is filled with melamine particles to ensure that the flue gas can fully contact the melamine particles when passing through. The size and shape of the filter are designed according to the needs of the actual flue gas treatment system to ensure that it can be installed in the existing flue gas treatment pipeline. The flue gas of the coal-fired power plant passes through the pretreatment system to remove most of the particulate matter and some harmful gases, and then enters the filter filled with melamine particles. In the filter, harmful gases in the flue gas, such as nitrogen oxides (NOx) and mercury (Hg), react chemically with the active components on the surface of the melamine particles and are effectively adsorbed and converted. The results are shown in Table 2.

[0058] Table 2

[0059] Experimental samples Out of stock rate (%) Mercury removal rate (%) Example 1 98 98 Comparative Example 1 85.2 87.6 Comparative Example 2 67.6 67.9 Comparative Example 3 70.6 68.6

[0060] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. 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 can 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 present invention.

Claims

1. A melamine particle, characterized in that: The melamine particles include the following raw materials in mass fractions: 55% to 65% melamine resin particles, 12% to 18% copper oxide, 8% to 12% cerium oxide, 4% to 6% manganese oxide, 4% to 6% aluminum oxide, 2% to 4% silicon oxide, and 1% to 3% graphene nanosheets.

2. The method for preparing melamine particles according to claim 1, characterized in that: include, Pretreatment: Wash the melamine resin particles with cleaning solution and deionized water, and dry them for later use; Preparing a solution: preparing a mixed solution of copper oxide, cerium oxide, manganese oxide, aluminum oxide and silicon oxide, and adjusting the pH to 4 to 6; Impregnation: Add the pretreated melamine resin particles into the mixed solution, stir at a constant speed, and impregnate for 30 minutes; Precipitation attachment: uniformly add alkaline solution until pH = 7, stirring continuously during the addition process; Aging treatment: Aging the mixed solution after precipitation attachment for 24 to 48 hours; Washing and drying: washing the particles with deionized water, ultrasonically cleaning and drying to obtain the melamine particles.

3. The preparation method according to claim 2, characterized in that: The cleaning solution is an ethanol solution with a concentration of 70% to 95%.

4. The preparation method according to claim 2, characterized in that: The drying temperature of the pretreatment is 80-90° C. and the time is 2-3 hours.

5. The preparation method according to claim 2, characterized in that: The uniform stirring, wherein the stirring rate is 100-200 r / min.

6. The preparation method according to claim 2, characterized in that: The alkaline solution in the precipitation attachment is sodium hydroxide solution or ammonia water.

7. The preparation method according to claim 2, characterized in that: The aging treatment is to age the mixed solution at 40-60° C. so that the precipitate forms a stable coating on the particle surface.

8. The preparation method according to claim 2, characterized in that: The ultrasonic cleaning, wherein the cleaning time is 30 minutes and the cleaning times are 3 times.

9. Use of the melamine particles obtained by the preparation method according to any one of claims 2 to 7 in the flue gas treatment process of a coal-fired power plant, using the melamine particles obtained by the preparation method according to any one of claims 2 to 7 as fillers to filter and adsorb the flue gas of a coal-fired power plant.

10. The use according to claim 9, characterized in that: The melamine particles serve as catalyst carriers, and the copper oxide, cerium oxide, manganese oxide, aluminum oxide and silicon oxide attached to the melamine particles can convert NOx and Hg in the flue gas into harmless or low-toxic substances.

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