A highly stable desulfurizing agent for removing SO2 and its preparation method
By introducing modified kaolin and silica into the manganese-based desulfurizer, loading and modifying it with Ni and Ce elements, the stability problem of the manganese-based desulfurizer in high humidity environment was solved, and a highly efficient SO2 removal effect was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING ZHONGKE QINGFENG ENVIRONMENTAL PROTECTION CO LTD
- Filing Date
- 2026-04-29
- Publication Date
- 2026-07-10
AI Technical Summary
Existing manganese-based desulfurizers have shortcomings in terms of mechanical strength and stability, especially in high-humidity environments where their structure is unstable and they cannot maintain high-efficiency desulfurization effects for a long time.
Manganese dioxide, calcium hydroxide, and iron oxide are used as active ingredients, combined with modified kaolin and silicon dioxide. By loading Ni and Ce elements and using N,N'-dihexadecylethylenediamine and octanoic acid to modify kaolin, the reactive sites are increased and the structural stability is improved.
This improved the structural stability and desulfurization efficiency of the desulfurizing agent under high humidity conditions, achieving a highly efficient SO2 removal effect.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of desulfurizing agent technology, and in particular to a highly stable desulfurizing agent for removing SO2 and its preparation method. Background Technology
[0002] With the acceleration of industrialization, the flue gas produced by burning coal and waste incineration includes SO2, HCl, and NO. x The emission of substances such as sulfur dioxide and sulfur dioxide can cause significant environmental damage. Among them, SO2, as one of the major air pollutants, is an important precursor to acid rain, sulfuric acid-type smog, and photochemical smog. It poses significant harm to the human respiratory system, the ecological environment, and building materials. Therefore, flue gas desulfurization technology has become a key focus in the industrial sector.
[0003] Flue gas desulfurization mainly employs two methods: wet desulfurization and dry desulfurization. Wet desulfurization utilizes aqueous solutions to absorb sulfur dioxide, forming sulfate ions to achieve desulfurization. However, the chemical reagents used in this method require purification and treatment, exacerbating environmental pollution. Dry desulfurization involves adding dry materials to the flue gas to absorb sulfur dioxide, such as calcium-based, manganese-based, or sodium-based desulfurizers. Manganese-based desulfurizers have received widespread attention in recent years due to their excellent redox properties, wide operating temperature window, and high desulfurization capacity. However, they still suffer from insufficient mechanical strength and poor stability. Therefore, it is usually necessary to introduce carriers or auxiliary components to improve the overall performance of the desulfurizer.
[0004] Patent CN 102039086 A discloses a medium-temperature iron-manganese desulfurizing agent and its preparation method. The main components of the desulfurizing agent are iron oxide and manganese oxide, combined with cement, bentonite, kaolin, attapulgite and other components. Although it has a good desulfurization effect and improves the mechanical strength of the desulfurizing agent to a certain extent, bentonite and kaolin have the limitation of poor water resistance, which makes it impossible for them to maintain the structural stability for a long time in the high humidity environment of the desulfurization process.
[0005] Therefore, there is an urgent need in the market for a desulfurizing agent that has high desulfurization efficiency and stability in removing SO2. Summary of the Invention
[0006] To address the problems existing in the prior art, this invention discloses a highly stable desulfurizing agent for removing SO2, which uses manganese dioxide, calcium hydroxide and iron oxide as active ingredients, and incorporates modified kaolin, along with silica and a binder, to give it the characteristics of high desulfurization efficiency and stability.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a highly stable desulfurizing agent for removing SO2, which comprises the following raw materials by weight: 80-100 parts of active ingredient, 1-4 parts of silicon dioxide, 15-20 parts of modified kaolin, and 2-5 parts of binder.
[0008] In some embodiments of the present invention, the active ingredient is a mixture of manganese-based materials, calcium-based materials and iron-based materials.
[0009] In some embodiments of the present invention, the active ingredient comprises the following components by weight: 70-80 parts manganese dioxide, 5-10 parts calcium hydroxide, and 5-10 parts iron oxide.
[0010] Preferably, the manganese dioxide has a particle size of 100-200 mesh; and the calcium hydroxide has a D90 of 10-20 μm.
[0011] In some embodiments of the present invention, the silica has a particle size of 350-400 mesh.
[0012] The applicant added a certain amount of silica with a particle size of 350-400 mesh, which played a dual role in supporting the skeleton and regulating the pores, thus improving the strength and desulfurization effect of the desulfurizer to a certain extent.
[0013] In some embodiments of the present invention, the method for preparing the modified kaolin includes the following steps: (1) Add nickel nitrate and cerium nitrate to deionized water, stir, add kaolin, stir, vacuum dry, calcine, cool and sieve to obtain powder for later use; (2) Add N,N'-bishexadecylethylenediamine to an aqueous ethanol solution, heat and stir, add acetic acid aqueous solution to adjust pH=5.5-6, stir, and obtain solution 1 for later use; add octanoic acid to an aqueous ethanol solution, heat and stir, and obtain solution 2 for later use; (3) Add the powder from step (1) to solution 1 from step (2), stir at 65-75℃ for 2-3 hours, filter, wash and add to solution 2, stir at 55-65℃ for 2-3 hours, adjust pH=5.5±0.2, filter, wash, dry and ball mill to obtain modified kaolin.
[0014] The kaolin has a particle size of 350-400 mesh.
[0015] In some embodiments of the present invention, in step (1), the mass ratio of kaolin to nickel nitrate and cerium nitrate is 1:(0.2-0.4):(0.1-0.3).
[0016] Preferably, in step (1), the mass ratio of kaolin to nickel nitrate and cerium nitrate is 1:0.25:0.15.
[0017] In some embodiments of the present invention, the mass ratio of the powder to N,N'-bishexadecylethylenediamine and octanoic acid is 1:(0.03-0.05):(0.01-0.03).
[0018] Preferably, the mass ratio of the powder to N,N'-bishexadecylethylenediamine and octanoic acid is 1:0.04:0.02.
[0019] In some embodiments of the present invention, in step (3), the ball milling conditions are zirconia balls at 450-550 rpm for 1.5-2.5 h.
[0020] Kaolin can act as a carrier and framework for loading active ingredients in desulfurizing agents, thereby improving the overall stability of the desulfurizing agent and making the desulfurization performance more efficient. However, kaolin has problems such as low surface activity, which prevents it from directly participating in the desulfurization reaction, and poor structural stability in high humidity environments.
[0021] To address the aforementioned issues, the applicant first loaded Ni and Ce elements onto kaolin, increasing the reactive sites of the kaolin and thus improving its SO2 removal efficiency. Furthermore, the introduction of Ni also enhanced the structural stability of the kaolin. Further, the applicant sequentially introduced N,N'-dihexadecylethylenediamine and octanoic acid to modify the Ni and Ce-loaded kaolin. The diamine structure of N,N'-dihexadecylethylenediamine allows for more stable adsorption onto the kaolin surface via hydrogen bonding, and also stabilizes the grafted hydrophobic chains. An anchoring layer is formed, and then octanoic acid is introduced. The hydrophobic chains of octanoic acid are embedded in the long chain gaps of N,N'-bishexadecylethylenediamine, forming a structure with alternating long and short chains, which reduces the surface porosity and thus synergistically gives the modified kaolin good hydrophobicity. Furthermore, the applicant finally uses appropriate ball milling to increase the specific surface area of the modified kaolin, so that the active ingredients in the desulfurizer can be better loaded, and the aforementioned hydrophobic modification can be more uniform, thus enabling the modified kaolin to maintain good structural stability in the high humidity environment of the desulfurization process.
[0022] In some embodiments of the present invention, the binder is bentonite or attapulgite.
[0023] In another aspect, the present invention provides a method for preparing a highly stable desulfurizing agent for removing SO2, comprising the following steps: The active ingredients, silica, modified kaolin, and binder are mixed, stirred, and ground to obtain a highly stable desulfurizing agent for removing SO2.
[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention discloses a highly stable desulfurizing agent for removing SO2, which uses manganese dioxide, calcium hydroxide and iron oxide as active ingredients, and incorporates modified kaolin, silicon dioxide and binder. Through the synergistic effect between the components, the desulfurizing agent for removing SO2 has high desulfurization efficiency and stability.
[0025] (2) The present invention designs and synthesizes a modified kaolin, which serves as a carrier and framework structure for loading active ingredients. First, Ni and Ce elements are loaded onto kaolin, which increases the reactive sites of kaolin and thus improves its SO2 removal effect. The introduction of Ni element also improves the structural stability of kaolin. Furthermore, the applicant sequentially introduces N,N'-dihexadecylethylenediamine and octanoic acid to modify the kaolin loaded with Ni and Ce elements, which synergistically gives the modified kaolin good hydrophobicity. Finally, with appropriate ball milling operation, the specific surface area of the modified kaolin is increased, so that the active ingredients in the desulfurizer are better loaded, and thus the modified kaolin still has good structural stability in the high humidity environment of the desulfurization process. Detailed Implementation
[0026] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.
[0027] In the following examples and comparative examples, except for the modified kaolin, all other compound monomers and related reagents used were commercially available. The particle size of manganese dioxide was 150 mesh; the D90 of calcium hydroxide was 15 μm; the particle size of silicon dioxide was 400 mesh; and the particle size of kaolin was 350 mesh.
[0028] Preparation Example 1 The synthesis method of modified kaolin A includes the following steps: (1) Add 2.5g nickel nitrate and 1.5g cerium nitrate to 50ml deionized water, stir for 30min, add 10g kaolin, stir for 24h, vacuum dry at 110℃ for 8h, heat to 450℃ at 2℃ / min, calcine for 2h, cool and sieve to obtain powder for later use. (2) Add 0.4g of N,N'-bishexadecylethylenediamine to 200ml of 80wt% ethanol aqueous solution, stir at 50℃ for 1h, add 1mol / L acetic acid aqueous solution to adjust pH=5.5, stir for 30min to obtain solution 1 for later use; add 0.2g of octanoic acid to 200ml of 80wt% ethanol aqueous solution, stir at 40℃ for 30min to obtain solution 2 for later use; (3) Add 10g of the powder from step (1) to solution 1 from step (2), stir at 70℃ for 2.5h, filter, wash with anhydrous ethanol, add to solution 2, stir at 60℃ for 2.5h, adjust pH=5.5 with 1mol / L acetic acid aqueous solution, filter, wash with anhydrous ethanol and deionized water in sequence, vacuum dry at 105℃ for 4h, and ball mill with zirconia balls at 500rpm for 2h (pause for 10min every 30min) to obtain modified kaolin A.
[0029] Preparation Example 2 Modified kaolin B is implemented in the same way as modified kaolin A, except that the mass of nickel nitrate in step (1) is replaced with 1.5g.
[0030] Preparation Example 3 Modified kaolin C is implemented in the same way as modified kaolin A, except that the mass of cerium nitrate in step (1) is replaced with 0.6g.
[0031] Preparation Example 4 Modified kaolin D is implemented in the same way as modified kaolin A, except that the mass of N,N'-bishexadecylethylenediamine in step (2) is replaced with 0.15g.
[0032] Preparation Example 5 Modified kaolin E is implemented in the same way as modified kaolin A, except that the mass of octanoic acid in step (2) is replaced with 0.05g.
[0033] Preparation Example 6 Modified kaolin F is implemented in the same way as modified kaolin A, except that step (3) is replaced by adding 10g of the powder from step (1) to solution 1 from step (2), stirring at 70°C for 2.5h, adjusting the pH to 5.5 with 1mol / L acetic acid aqueous solution, filtration, washing with anhydrous ethanol, vacuum drying at 105°C for 4h, and ball milling with zirconia balls at 500rpm for 2h (pausing for 10min every 30min) to obtain modified kaolin F.
[0034] Preparation Example 7 Modified kaolin G is implemented in the same way as modified kaolin A, except that step (3) is replaced by adding 10g of the powder from step (1) to solution 2 from step (2), stirring at 60°C for 2.5h, adjusting the pH to 4 with 1mol / L acetic acid aqueous solution, filtration, washing with anhydrous ethanol and deionized water in sequence, vacuum drying at 105°C for 4h, and ball milling with zirconia balls at 500rpm for 2h (pausing for 10min every 30min) to obtain modified kaolin G.
[0035] Preparation Example 8 Modified kaolin H is implemented in the same way as modified kaolin A, except that the ball milling step in step (3) is deleted.
[0036] Example 1 A highly stable desulfurizing agent for removing SO2, comprising the following raw materials by weight: 90 parts of active ingredient, 2.5 parts of silica, 18 parts of modified kaolin A, and 3.5 parts of bentonite.
[0037] By weight, the active ingredients include the following components: 75 parts manganese dioxide, 7.5 parts calcium hydroxide, and 7.5 parts iron oxide.
[0038] The preparation method of the highly stable desulfurizing agent for removing SO2 in this embodiment includes the following steps: The active ingredient, silica, modified kaolin A and bentonite are mixed, stirred for 1 hour and ground for 15 minutes to obtain a highly stable desulfurizing agent for removing SO2.
[0039] Example 2 A highly stable desulfurizing agent for removing SO2, comprising the following raw materials by weight: 80 parts of active ingredient, 1 part of silicon dioxide, 15 parts of modified kaolin A, and 2 parts of attapulgite.
[0040] By weight, the active ingredients include the following components: 70 parts manganese dioxide, 5 parts calcium hydroxide, and 5 parts iron oxide.
[0041] The preparation method of the highly stable desulfurizing agent for removing SO2 in this embodiment includes the following steps: The active ingredient, silica, modified kaolin A and attapulgite are mixed, stirred for 1 hour and ground for 10 minutes to obtain a highly stable desulfurizing agent for removing SO2.
[0042] Example 3 A highly stable desulfurizing agent for removing SO2, comprising the following raw materials by weight: 100 parts of active ingredient, 4 parts of silica, 20 parts of modified kaolin A, and 5 parts of bentonite.
[0043] By weight, the active ingredients include the following components: 80 parts manganese dioxide, 10 parts calcium hydroxide, and 10 parts iron oxide.
[0044] The preparation method of the highly stable desulfurizing agent for removing SO2 in this embodiment includes the following steps: The active ingredient, silica, modified kaolin A and bentonite are mixed, stirred for 1 hour and ground for 20 minutes to obtain a highly stable desulfurizing agent for removing SO2.
[0045] Example 4 This embodiment provides a highly stable desulfurizing agent for removing SO2 and its preparation method. The specific implementation method is the same as in Embodiment 1, except that the particle size of silica is replaced with 300 mesh.
[0046] Example 5 This embodiment provides a highly stable desulfurizing agent for removing SO2 and its preparation method. The specific implementation method is the same as in Embodiment 1, except that modified kaolin B replaces modified kaolin A in an equal amount.
[0047] Example 6 This embodiment provides a highly stable desulfurizing agent for removing SO2 and its preparation method. The specific implementation method is the same as in Embodiment 1, except that modified kaolin C is used to replace modified kaolin A in an equal amount.
[0048] Example 7 This embodiment provides a highly stable desulfurizing agent for removing SO2 and its preparation method. The specific implementation method is the same as in Embodiment 1, except that modified kaolin D is used to replace modified kaolin A in an equal amount.
[0049] Example 8 This embodiment provides a highly stable desulfurizing agent for removing SO2 and its preparation method. The specific implementation method is the same as in Embodiment 1, except that modified kaolin E is used to replace modified kaolin A in an equal amount.
[0050] Example 9 This embodiment provides a highly stable desulfurizing agent for removing SO2 and its preparation method. The specific implementation method is the same as in Embodiment 1, except that modified kaolin F is used to replace modified kaolin A in an equal amount.
[0051] Example 10 This embodiment provides a highly stable desulfurizing agent for removing SO2 and its preparation method. The specific implementation method is the same as in Embodiment 1, except that modified kaolin G is used to replace modified kaolin A in an equal amount.
[0052] Example 11 This embodiment provides a highly stable desulfurizing agent for removing SO2 and its preparation method. The specific implementation method is the same as in Embodiment 1, except that modified kaolin H is used to replace modified kaolin A in equal amounts.
[0053] Comparative Example 1 This embodiment provides a highly stable desulfurizing agent for removing SO2 and its preparation method. The specific implementation method is the same as in Embodiment 1, except that kaolin is used to replace modified kaolin A in an equal amount.
[0054] Performance testing The relevant performance of the desulfurizers in Examples 1-11 and Comparative Example 1 were tested, and the test results are shown in Table 1.
[0055] Desulfurization performance: The desulfurizing agents used in Examples 1-11 and Comparative Example 1 were used to conduct desulfurization tests on flue gas from a waste incineration plant in a county in southwestern my country. The SO2 concentration in the flue gas was measured hourly at both the inlet and outlet, and the average value was calculated based on 48 hours of data. The high-temperature flue gas treatment capacity was 16000 Nm³. 3 / h, residence time greater than or equal to 4s, and control the amount of desulfurizing agent used to be 15kg / t of waste.
[0056] SO2 removal rate = (C0-C) / C0×100%; CO—SO2 concentration in high-temperature flue gas before it passes through the desulfurizing agent; C—SO2 concentration in high-temperature flue gas after passing through the desulfurizing agent; Compressive strength: The radial compressive strength of the desulfurizing agents in Examples 1-11 and Comparative Example 1 was tested with reference to standard HG / T 2782-2011.
[0057] Table 1
[0058] As shown in Table 1, the desulfurizers in Examples 1-3 of this invention all exhibit high desulfurization efficiency and compressive strength, meaning they possess both high desulfurization efficiency and stability. Specifically, Example 4 altered the particle size of silica, resulting in a slight decrease in the strength and desulfurization effect of the desulfurizer. Examples 5-11, respectively, altered the doping ratio of key components nickel and cerium in the modified kaolin synthesis process, the modification ratio of N,N'-dihexadeciylethylenediamine and octanoic acid, and the methods of not using N,N'-dihexadeciylethylenediamine or octanoic acid, or grinding to modify kaolin, resulting in a decrease in the surface activity, hydrophobicity, and stability of the modified kaolin, thus leading to a decrease in both the desulfurization efficiency and stability of the desulfurizer. Comparative Example 1, where kaolin was used to replace modified kaolin A in equal amounts, showed even worse results in both desulfurization efficiency and stability.
[0059] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.
Claims
1. A highly stable desulfurizing agent for removing SO2, characterized in that, The desulfurizing agent comprises the following raw materials by weight: 80-100 parts of active ingredient, 1-4 parts of silicon dioxide, 15-20 parts of modified kaolin, and 2-5 parts of binder.
2. The highly stable desulfurizing agent for removing SO2 according to claim 1, characterized in that, The active ingredient is a mixture of manganese-based, calcium-based, and iron-based materials.
3. The highly stable desulfurizing agent for removing SO2 according to claim 2, characterized in that, By weight, the active ingredients include the following components: 70-80 parts manganese dioxide, 5-10 parts calcium hydroxide, and 5-10 parts iron oxide.
4. The highly stable desulfurizing agent for removing SO2 according to claim 1, characterized in that, The silica has a particle size of 350-400 mesh.
5. The highly stable desulfurizing agent for removing SO2 according to claim 1, characterized in that, The method for preparing the modified kaolin includes the following steps: (1) Add nickel nitrate and cerium nitrate to deionized water, stir, add kaolin, stir, vacuum dry, calcine, cool and sieve to obtain powder for later use; (2) Add N,N'-bishexadecylethylenediamine to an aqueous ethanol solution, heat and stir, add acetic acid aqueous solution to adjust pH=5.5-6, stir, and obtain solution 1 for later use; add octanoic acid to an aqueous ethanol solution, heat and stir, and obtain solution 2 for later use; (3) Add the powder from step (1) to solution 1 from step (2), stir at 65-75℃ for 2-3 hours, filter, wash and add to solution 2, stir at 55-65℃ for 2-3 hours, adjust pH=5.5±0.2, filter, wash, dry and ball mill to obtain modified kaolin.
6. The highly stable desulfurizing agent for removing SO2 according to claim 5, characterized in that, In step (1), the mass ratio of kaolin to nickel nitrate and cerium nitrate is 1:(0.2-0.4):(0.1-0.3).
7. The highly stable desulfurizing agent for removing SO2 according to claim 5, characterized in that, The mass ratio of the powder to N,N'-bishexadecylethylenediamine and octanoic acid is 1:(0.03-0.05):(0.01-0.03).
8. The highly stable desulfurizing agent for removing SO2 according to claim 5, characterized in that, In step (3), the ball milling conditions are zirconia balls at 450-550 rpm for 1.5-2.5 hours.
9. The highly stable desulfurizing agent for removing SO2 according to claim 1, characterized in that, The binder is bentonite or attapulgite.
10. A method for preparing a highly stable desulfurizing agent for removing SO2 according to any one of claims 1-9, characterized in that, Includes the following steps: The active ingredients, silica, modified kaolin, and binder are mixed, stirred, and ground to obtain a highly stable desulfurizing agent for removing SO2.