Environment-friendly strong-arsenic-resistance denitration catalyst and preparation method thereof
By loading α-MnO2 onto TiO2 or vanadium-titanium-based catalysts and depositing rare earth oxides, an environmentally friendly and highly arsenic-resistant denitrification catalyst is formed, solving the problem of SCR catalyst poisoning and achieving a wide temperature window and high arsenic resistance performance, making it suitable for complex industrial flue gas treatment.
Patent Information
- Application Number
- CN202511004898.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-21
- Publication Date
- 2025-11-25
AI Technical Summary
Existing SCR catalysts are susceptible to arsenic poisoning from flue gas, leading to decreased denitrification activity and shortened service life. Furthermore, traditional preparation methods cause secondary pollution to the environment.
By using a solid-phase mixing method to support α-MnO2 and a hydrothermal method to deposit rare earth oxides on TiO2 or vanadium-titanium-based catalysts, an environmentally friendly and highly resistant arsenic denitrification catalyst is formed, providing a wide activity temperature window and high efficiency in resisting arsenic poisoning.
It broadens the denitrification activity temperature window of the catalyst, enhances its resistance to arsenic poisoning, reduces the energy consumption of the preparation process, and is suitable for the treatment of complex industrial flue gas.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of SCR denitration catalyst preparation, in particular to an environment-friendly strong arsenic-resistant denitration catalyst and a preparation method thereof. BACKGROUND
[0002] Selective Catalytic Reduction (SCR) technology is the most widely used flue gas denitration technology at present, and its core is denitration catalyst. SCR catalyst can reduce NO x to N2 and H2O at high temperature, thereby achieving efficient removal of NO x .
[0003] However, in the actual operation process, the SCR catalyst is easily poisoned by fly ash and toxic elements in the flue gas, resulting in a decrease in its denitration activity and a shortening of its service life. Among them, arsenic (As) is one of the most toxic elements in the SCR catalyst. Arsenic poisoning can cover or destroy the active sites of the catalyst, significantly reducing the denitration efficiency of the catalyst. Especially in coal-fired power plants, arsenic in the flue gas mainly exists in the form of As2O3, which is volatile and has strong toxicity, and is easy to cause poisoning and deactivation of the catalyst.
[0004] In order to improve the arsenic poisoning resistance of the SCR catalyst, researchers have conducted a lot of research. The traditional arsenic poisoning resistance methods mainly include catalyst surface modification, addition of arsenic-resistant additives, etc. However, these methods often have problems such as narrow active temperature window, limited arsenic poisoning resistance effect, etc., which are difficult to meet the needs of actual application. Therefore, developing an environment-friendly denitration catalyst with a wide active temperature window and strong arsenic poisoning resistance has become the focus of current research.
[0005] In addition, with the increasingly stringent environmental regulations, the preparation method of the catalyst also needs to be more environmentally friendly and efficient. Traditional catalyst preparation methods often use a large amount of chemical reagents, producing a lot of wastewater, waste gas and waste residue, causing secondary pollution to the environment. Therefore, developing an environmentally friendly catalyst preparation method to reduce the negative impact on the environment is also an important direction of current research.
[0006] In view of this, the present application is proposed. SUMMARY
[0007] The purpose of the present application is to provide an environment-friendly strong arsenic-resistant denitration catalyst and a preparation method thereof. The catalyst prepared by the method has the effects of wide active temperature window and excellent arsenic poisoning resistance.
[0008] In the first aspect, the present application provides a preparation method of an environment-friendly strong arsenic-resistant denitration catalyst, comprising the following steps:
[0009] S1, uniformly mixing anatase TiO2 or a commercial vanadium-titanium-based catalyst with KMnO4 and manganese acetate and ball milling to obtain a mixed powder;
[0010] S2, dissolving an auxiliary precursor salt in an organic solvent and adding the mixed powder to obtain a mixed solution A after stirring;
[0011] S3, dissolving NaOH or KOH in an organic solvent and slowly adding to the mixed solution A to obtain a mixed solution B;
[0012] S4, transferring the mixed solution B to a hydrothermal kettle for hydrothermal crystallization, cooling and centrifuging to obtain a precipitate, and drying the precipitate after washing with water to obtain an environmentally friendly strong arsenic-resistant denitration catalyst.
[0013] In the preparation method of the present application, first, a solid-phase mixing method is used to load α-MnO2 on the carrier TiO2 or the commercial vanadium-titanium-based catalyst to provide high-activity low-temperature denitration active sites, wherein the anatase TiO2 has a high specific surface area and good photocatalytic performance, can provide abundant active sites, promote adsorption and reaction of reactants, and prevent α-MnO2 from being deactivated in the reaction. KMnO4 as a strong oxidizing agent can oxidize Mn(II) to Mn(IV) to generate α-MnO2, which has abundant surface oxygen vacancies and high oxidation state Mn, can effectively adsorb and activate NO x , and α-MnO2 can still exhibit excellent redox performance at low temperature. Ball milling can enhance the anti-sintering ability of the nanostructure and prolong the service life of the catalyst. The commercial vanadium-titanium-based catalyst has good thermal stability and catalytic activity, and can also be used as a stable carrier to prevent α-MnO2 from being deactivated in the reaction. Then, a hydrothermal method is used to uniformly deposit rare earth oxides on the carrier TiO2 or the commercial vanadium-titanium-based catalyst to provide high-activity medium-high-temperature denitration active sites and high-activity As adsorption sites, thereby achieving the dual functions of expanding the denitration activity temperature window of the catalyst and enhancing the arsenic poisoning resistance. Therefore, the catalyst prepared by the present application not only has the effects of wide activity temperature window and excellent arsenic poisoning resistance, but also avoids the high energy consumption generated in the traditional impregnation, drying and calcination process, and is an environmentally friendly strong arsenic-resistant denitration catalyst.
[0014] As a preferred embodiment of the present application, the molar ratio of anatase TiO2 or a commercial vanadium-titanium-based catalyst to KMnO4 and manganese acetate is 380:38:57-380:5:15.
[0015] As the preferred technical solution, the rare earth oxide can significantly improve the medium-high temperature denitration activity and the anti-As poisoning performance of the catalyst due to its unique redox performance, surface oxygen vacancy formation ability and strong adsorption effect on As. By depositing the rare earth oxide on the TiO2 or vanadium-titanium-based catalyst through the hydrothermal method, the temperature window of the denitration activity can be widened and the anti-As poisoning performance can be enhanced, thereby meeting the needs of complex industrial flue gas treatment. Therefore, the additive precursor salt in the application includes any one of cerium nitrate, lanthanum nitrate, neodymium nitrate and praseodymium nitrate;
[0016] The organic solvent includes any one of methanol, ethanol and isopropanol.
[0017] As the preferred technical solution, in the application, NaOH or KOH is mainly used for precipitating the additive precursor salt, such as cerium nitrate, lanthanum nitrate, neodymium nitrate and praseodymium nitrate, to form hydroxide and deposit on the carrier, and then hydrothermal crystallization is performed to form nano-oxide. Specifically, in the mixed solution B, n(OH - ):n(Ce / La / Nd / Pr)=4:1~10:1, that is, the molar ratio of OH - to Ce, La, Nd or Pr is 4:1-10:1.
[0018] As the preferred technical solution, the milling time is controlled to be 1-4h to ensure that the components are in sufficient contact, improve the reaction efficiency, reduce the particle size, increase the specific surface area and improve the catalytic activity.
[0019] As the preferred technical solution, the hydrothermal crystallization temperature is controlled to be 140-180℃ and the time is controlled to be 4-10h.
[0020] As the preferred technical solution, the commercial vanadium-titanium-based catalyst includes any one of V2O5-WO3 / TiO2, V2O5-MoO3 / TiO2 and V2O5-CeO2 / TiO2.
[0021] As the preferred technical solution, in the strong anti-arsenic denitration catalyst, the mass fraction of MnO2 is 0.5%-5%.
[0022] As the preferred technical solution, in the strong anti-arsenic denitration catalyst, the mass fraction of CeO2, La2O3, Nd2O3 or Pr2O3 is 0.5%-5%.
[0023] In the second aspect, the application also discloses an environment-friendly strong anti-arsenic denitration catalyst prepared by the above method, which also belongs to the protection range of the application.
[0024] The preparation method of the environment-friendly strong anti-arsenic denitration catalyst has the following beneficial effects:
[0025] 1、The application adopts solid phase mixing method to load alpha-MnO2 on carrier TiO2 or commercial vanadium-titanium-based catalyst to provide high-activity low-temperature denitration active sites, further adopts hydrothermal method to uniformly deposit rare earth oxides on carrier TiO2 or commercial vanadium-titanium-based catalyst to provide high-activity medium-high-temperature denitration active sites, and also provide high-activity As adsorption sites, so as to achieve the dual functions of expanding the denitration activity temperature window of the catalyst and enhancing the anti-As poisoning performance;
[0026] 2、The preparation method of the environment-friendly strong anti-arsenic denitration catalyst provided by the application adopts ball milling and hydrothermal preparation methods, which can not only realize uniform loading of active components and additives on the carrier, but also can avoid high energy consumption generated in the traditional impregnation, drying and calcination processes.
[0027] 3、The preparation method of the environment-friendly strong anti-arsenic denitration catalyst provided by the application is also suitable for traditional vanadium-titanium-based denitration catalysts, and can be used as an effective means to improve the anti-As poisoning performance of the catalyst. DETAILED DESCRIPTION
[0028] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
[0029] It should be noted that the terms used herein are only intended to describe specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form also includes the plural form unless the context clearly indicates otherwise, and furthermore, it should be understood that when the terms "comprise" and / or "include" are used in the specification, there is a feature, step, operation, device, component and / or combination thereof.
[0030] The technical solutions of the present application will be described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.
[0031] Example 1
[0032] S1, mix anatase TiO2, KMnO4 and manganese acetate uniformly and ball mill for 3h to obtain a mixed powder, wherein the molar ratio of anatase TiO2, KMnO4 and manganese acetate is 20:2:3;
[0033] S2, dissolve cerium nitrate in methanol, and add the mixed powder, stir vigorously, to obtain mixed solution A;
[0034] S3, dissolve NaOH in methanol, and slowly add to mixed solution A, to obtain mixed solution B, wherein n(OH - ):n(Ce)=4:1;
[0035] S4, transfer mixed solution B to an autoclave, hydrothermal crystallization at 140-180℃ for 4-10h, cool, centrifuge, to obtain a deposit, which is washed with water, dried, to obtain an environmentally friendly strong arsenic-resistant denitration catalyst.
[0036] Example 2
[0037] S1, mix anatase TiO2, KMnO4 and manganese acetate uniformly and ball mill for 4h, to obtain a mixed powder, wherein the molar ratio of anatase TiO2, KMnO4 and manganese acetate is 17:1:2;
[0038] S2, dissolve lanthanum nitrate in ethanol, and add the mixed powder, stir vigorously, to obtain mixed solution A;
[0039] S3, dissolve KOH in ethanol, and slowly add to mixed solution A, to obtain mixed solution B, wherein n(OH - ):n(La)=7:1;
[0040] S4, transfer mixed solution B to an autoclave, hydrothermal crystallization at 140-180℃ for 4-10h, cool, centrifuge, to obtain a deposit, which is washed with water, dried, to obtain an environmentally friendly strong arsenic-resistant denitration catalyst.
[0041] Example 3
[0042] S1, mix anatase TiO2, KMnO4 and manganese acetate uniformly and ball mill for 2h, to obtain a mixed powder, wherein the molar ratio of anatase TiO2, KMnO4 and manganese acetate is 22:1:2;
[0043] S2, dissolve neodymium nitrate in ethanol, and add the mixed powder, stir vigorously, to obtain mixed solution A;
[0044] S3, dissolve NaOH in ethanol, and slowly add to mixed solution A, to obtain mixed solution B, wherein n(OH - ):n(Nd)=10:1;
[0045] S4, transfer mixed solution B to an autoclave, hydrothermal crystallization at 140-180℃ for 4-10h, cool, centrifuge, to obtain a deposit, which is washed with water, dried, to obtain an environmentally friendly strong arsenic-resistant denitration catalyst.
[0046] Example 4
[0047] S1, mix anatase TiO2, KMnO4 and manganese acetate uniformly and ball mill for 3h to obtain a mixed powder, wherein the molar ratio of anatase TiO2, KMnO4 and manganese acetate is 90:3:7;
[0048] S2, dissolve cerium nitrate and lanthanum nitrate in methanol and add the mixed powder to obtain a mixed solution A after stirring vigorously;
[0049] S3, dissolve NaOH in methanol and slowly add to the mixed solution A to obtain a mixed solution B, wherein n(OH - ):n(Ce / La) = 4:1;
[0050] S4, transfer the mixed solution B to an autoclave and hydrothermally crystallize at 140-180℃ for 4-10h, cool and centrifuge to obtain a deposit, which is washed with water and dried to obtain an environmentally friendly strong arsenic-resistant denitration catalyst.
[0051] Example 5
[0052] S1, mix a commercial vanadium-titanium-based catalyst, KMnO4 and manganese acetate uniformly and ball mill for 3h to obtain a mixed powder, wherein the molar ratio of the commercial vanadium-titanium-based catalyst, KMnO4 and manganese acetate is 76:1:3;
[0053] S2, dissolve cerium nitrate in isopropyl alcohol and add the mixed powder to obtain a mixed solution A after stirring vigorously;
[0054] S3, dissolve NaOH in isopropyl alcohol and slowly add to the mixed solution A to obtain a mixed solution B, wherein n(OH - ):n(Ce) = 5:1;
[0055] S4, transfer the mixed solution B to an autoclave and hydrothermally crystallize at 140-180℃ for 4-10h, cool and centrifuge to obtain a deposit, which is washed with water and dried to obtain an environmentally friendly strong arsenic-resistant denitration catalyst.
[0056] Comparative Example 1
[0057] This comparative example is basically the same as Example 1, except that manganese acetate is replaced by zinc acetate.
[0058] Comparative Example 2
[0059] S1, mix anatase TiO2, KMnO4 and manganese acetate uniformly and ball mill for 3h to obtain a mixed powder, wherein the molar ratio of anatase TiO2, KMnO4 and manganese acetate is 20:2:3;
[0060] S2, dissolve NaOH in methanol, and add the mixed powder, stir vigorously to obtain mixed solution A;
[0061] S3, transfer mixed solution A into an autoclave and hydrothermal crystallize at 140-180℃ for 4-10h, cool, centrifuge to obtain a precipitate, wash the precipitate with water, and dry to obtain a denitration catalyst.
[0062] Comparative Example 3
[0063] S1, mix anatase TiO2, KMnO4 and manganese acetate uniformly and ball mill for 4h to obtain a mixed powder, wherein the molar ratio of anatase TiO2, KMnO4 and manganese acetate is 17:1:2;
[0064] S2, dissolve lanthanum nitrate in ethanol, and add the mixed powder, stir vigorously to obtain mixed solution A;
[0065] S3, centrifuge mixed solution A to obtain a precipitate, wash the precipitate with water, and dry to obtain a denitration catalyst.
[0066] Comparative Example 4
[0067] A commercial anti-arsenic denitration catalyst, mainly composed of TiO2, V2O5, MoO3, SiO2, lactic acid and glass fiber, uses Mo as an anti-arsenic additive, and each element is combined by adding water and ammonia through mixing and kneading, and the denitration catalyst is obtained by calcination.
[0068] Test Example 1
[0069] In order to study the activity of the denitration catalysts prepared in the above examples and comparative examples, the denitration efficiency of the catalysts was tested at a flue gas temperature of 200-450℃, and the test results are shown in Table 1.
[0070] The test conditions are as follows:
[0071] The test temperature is 200-450℃, the volume concentration of NH3 is 500ppm, NH3 / NO=1, the volume concentration of SO2 is 300ppm, and GHSV=60000h -1 .
[0072] Table 1 Denitration efficiency of different catalysts
[0073]
[0074] From table 1, the present application loads alpha-MnO2 on the carrier TiO2 or commercial vanadium-titanium-based catalyst to provide high-activity low-temperature denitration active sites, and the introduction of rare earth oxides significantly improves the denitration activity of the catalyst in the medium-high temperature range, making up for the insufficient activity of traditional vanadium-titanium-based catalysts at high temperatures. Therefore, the preparation method of the present application widens the denitration activity temperature window of the catalyst to a certain extent.
[0075] Test Example 2
[0076] In order to further verify the arsenic poisoning resistance of the denitration catalyst prepared in the above examples and control examples, the denitration catalysts in the above examples and control examples were subjected to simulated arsenic poisoning, and the test results are shown in Table 2.
[0077] The arsenic poisoning of the denitration catalyst was carried out by a simulated poisoning method, specifically as follows:
[0078] The catalyst powder was weighed and placed in a tubular furnace, and a certain amount of As2O3 was placed at the front end of the denitration catalyst. 3vol% H2O-containing N2 was introduced into the tubular furnace, and heated to 350℃, and As2O3 vapor will be loaded on the denitration catalyst with gas flow. Subsequently, the denitration catalyst was treated in a 3vol% O2-containing N2 atmosphere at 370℃ for 10h, to obtain a simulated arsenic-poisoned denitration catalyst.
[0079] The test conditions are as follows:
[0080] The test temperature was 300℃, the volume concentration of NH3 was 500ppm, NH3 / NO was 1, the volume concentration of SO2 was 300ppm, and GHSV was 60000h -1 .
[0081] Table 2 Denitration efficiency of different catalysts
[0082]
[0083]
[0084] From table 2, the present application uniformly deposits rare earth oxides on TiO2 or vanadium-titanium-based catalysts by a hydrothermal method, and the rare earth oxides protect the active sites of the catalyst by adsorbing and fixing As, significantly prolonging the service life of the catalyst and enhancing its As poisoning resistance.
[0085] To sum up, the preparation method of the application not only widens the temperature window of the catalyst de-NOx activity, but also enhances the anti-As poisoning performance of the de-NOx catalyst, and can meet the needs of complex industrial flue gas treatment. In addition, the preparation method adopts ball milling and hydrothermal preparation, which can not only realize uniform loading of the active component and the additive on the carrier, but also can avoid high energy consumption generated in the traditional impregnation, drying and calcination process. The prepared catalyst is an environment-friendly strong anti-arsenic de-NOx catalyst.
[0086] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.
Claims
1. A method for preparing an environmentally friendly strong arsenic-resistant denitration catalyst, characterized in that, The method comprises the following steps: S1, uniformly mixing anatase TiO2 or a commercial vanadium-titanium-based catalyst with KMnO4 and manganese acetate and ball milling to obtain a mixed powder; S2, dissolving an auxiliary precursor salt in an organic solvent and adding the mixed powder to obtain a mixed solution A by stirring; S3, dissolving NaOH or KOH in an organic solvent and slowly adding to the mixed solution A to obtain a mixed solution B; S4, transferring the mixed solution B to a hydrothermal kettle for hydrothermal crystallization, cooling and centrifuging to obtain a deposit, and drying the deposit after washing with water to obtain an environmentally friendly strong arsenic-resistant denitration catalyst.
2. The production method according to claim 1, characterized by, The molar ratio of the anatase TiO2 or the commercial vanadium-titanium-based catalyst to KMnO4 and manganese acetate is 380:38:57-380:5:
15.
3. The preparation method according to claim 1, characterized in that, The auxiliary precursor salt comprises any one of cerium nitrate, lanthanum nitrate, neodymium nitrate and praseodymium nitrate. The organic solvent comprises any one of methanol, ethanol and isopropyl alcohol.
4. The method of claim 1, wherein, n (OH - ):n(Ce / La / Nd / Pr)=4:1~10:
1.
5. The preparation method according to claim 1, characterized in that, The ball milling time is controlled to be 1-4 h.
6. The method of claim 1, wherein, The hydrothermal crystallization temperature is controlled to be 140-180℃ and the time is controlled to be 4-10 h.
7. The preparation method according to claim 1, characterized in that, The commercial vanadium-titanium-based catalyst comprises any one of V2O5-WO3 / TiO2, V2O5-MoO3 / TiO2 and V2O5-CeO2 / TiO2.
8. The method of claim 1, wherein, The mass fraction of MnO2 in the strong arsenic-resistant denitration catalyst is 0.5%-5%.
9. The method of claim 1, wherein, The mass fraction of CeO2, La2O3, Nd2O3 or Pr2O3 in the strong arsenic-resistant denitration catalyst is 0.5%-5%.
10. An environmentally friendly strong arsenic resistant denitration catalyst, characterized in that, The method is prepared according to any one of claims 1-9.