Novel wet flue gas desulfurization composite synergistic additive and preparation method thereof

Abstract

The invention discloses a novel wet flue gas desulfurization composite synergistic additive and a preparation method thereof, and relates to the technical field of flue gas desulfurization. The novel wet flue gas desulfurization composite synergistic additive comprises the following raw materials in parts by weight: 15-25 parts of organic acid, 10-20 parts of organic salt, 5-10 parts of inorganic salt, 4-5 parts of a wetting agent, 5-8 parts of a moisture absorbent and 5-15 parts of an accelerant. The prepared novel wet flue gas desulfurization composite synergistic additive has good calcium carbonate dissolution rate and calcium sulfite oxidation rate, and the desulfurization efficiency is high.

Description

Technical Field

[0001] This invention relates to the field of flue gas desulfurization technology, specifically to a novel composite synergistic additive for wet flue gas desulfurization and its preparation method. Background Technology

[0002] Wet flue gas desulfurization (FGD) technology has become a core treatment process for flue gas from coal-fired power plants and other industrial furnaces due to its high desulfurization efficiency, reliable operation, and abundant absorbent resources. However, in actual operation, this process still generally faces problems such as high SO2 gas-liquid mass transfer resistance, slow limestone dissolution rate, and difficulty in oxidizing the intermediate product calcium sulfite. This leads to a series of problems, including the inability to further improve desulfurization efficiency, low limestone utilization, poor by-product quality, system scaling and blockage, and high operating energy consumption. To overcome these problems, adding desulfurization synergists has become an economical and effective technical means. However, existing synergists suffer from poor synergy among their components and unsatisfactory desulfurization effects.

[0003] Chinese invention patent CN105664702A discloses a composite synergistic additive for wet flue gas desulfurization and its preparation method. The weight ratio of each component in the composite synergistic additive is as follows: adipic acid 55-80 parts; nylon acid 5-15 parts; sodium citrate 5-14 parts; sodium sulfate 1-10 parts; ferric sulfate 3-10 parts; and manganese chloride 2-10 parts. The preparation method of the above composite synergistic additive is as follows: under normal temperature and pressure, adipic acid, nylon acid, sodium citrate, sodium sulfate, ferric sulfate, and manganese chloride are weighed according to the weight ratio of each component and mixed evenly. The desulfurization composite synergistic additive in this invention is simple to prepare and low in cost, but its desulfurization efficiency is generally low. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a novel composite additive for wet flue gas desulfurization and its preparation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A novel composite additive for wet flue gas desulfurization comprises the following raw materials in parts by weight: 15-25 parts organic acid, 10-20 parts organic salt, 5-10 parts inorganic salt, 4-5 parts wetting agent, 5-8 parts hygroscopic agent, and 5-15 parts accelerator; The accelerator is prepared by the following method: S1: Cyanurium chloride reacts with dopamine to produce intermediate 1, and the reaction equation is shown below:

[0006] S2: Intermediate 1 reacts with 4-amino-2,2,6,6-tetramethylpiperidine-1-oxo radical to generate intermediate 2, as shown in the following schematic equation:

[0007] S3: Intermediate 2 reacts with 5-aminovaleric acid to generate intermediate 3, and the reaction equation is shown below:

[0008] S4: Intermediate 3 reacts with 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammonium)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium))bis(propane-1-sulfonate) to give the promoter, and the reaction equation is shown below:

[0009] In step S1, the molar ratio of cyanuric chloride to dopamine is 1:(1.05-1.1).

[0010] In step S2, the molar ratio of intermediate 1 to 4-amino-2,2,6,6-tetramethylpiperidine-1-oxy radical is 1:(1.05-1.1).

[0011] In step S3, the molar ratio of intermediate 2 to 5-aminovaleric acid is 1:(1.1-1.2).

[0012] In step S4, the molar ratio of intermediate 3 to 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammonium)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium))bis(propane-1-sulfonate) is 1:(3.1-3.2).

[0013] The organic acid is one of benzoic acid and adipic acid.

[0014] The organic salt is one of sodium acetate or sodium citrate.

[0015] The inorganic salt is either magnesium sulfate or sodium sulfate.

[0016] The wetting agent is sodium dodecylbenzenesulfonate; the hygroscopic agent is magnesium chloride.

[0017] A method for preparing a novel composite synergistic additive for wet flue gas desulfurization includes the following steps: (1) Weigh out the following by weight: 15-25 parts organic acid, 10-20 parts organic salt, 5-10 parts inorganic salt, 4-5 parts wetting agent, 5-8 parts hygroscopic agent, and 5-15 parts accelerator; (2) Mix the above materials, stir evenly, and grind them into powder in a planetary ball mill to obtain a new type of wet flue gas desulfurization composite additive.

[0018] Due to the adoption of the above technical solutions, the beneficial effects of the present invention include: The novel wet flue gas desulfurization composite additive prepared by this invention has good calcium carbonate solubility and calcium sulfite oxidation rate, resulting in high desulfurization efficiency. The added promoter improves the calcium carbonate solubility through catechol groups; and improves the calcium sulfite oxidation rate through the synergistic effect of quaternary ammonium salt, nitroxide radicals, sulfonate groups and long-chain alkyl groups. The combined effect of these structures significantly improves the desulfurization efficiency. Attached Figure Description

[0019] Figure 1 The 1H NMR spectrum of the promoter prepared in Example 2. Detailed Implementation

[0020] The following description, in conjunction with specific embodiments, provides further details, but the present invention is not limited to these embodiments.

[0021] Example 1 Preparation of 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammonium)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium))bis(propane-1-sulfonate): N1: Under nitrogen protection, 150 ml of anhydrous tetrahydrofuran was mixed with 0.105 mol of dodecylamine and stirred until homogeneous. 0.1 mol of 2-chloroethanol was slowly added dropwise over 10 min. Then, 0.15 mol of triethylamine was added, and the mixture was reacted at 50 °C for 5 h. After cooling to room temperature, the mixture was washed three times with 80 ml of saturated brine, dried over 10 g of anhydrous magnesium sulfate for 2 h, filtered, and distilled under reduced pressure at 40 °C for 2 h to obtain 2-(dodecylamino)ethanol. The reaction equation is shown below:

[0022] Its 1H NMR data are as follows: 1 H NMR (400 MHz, DMSO-d6) δ 4.25 (t, J = 5.0 Hz,1H), 3.50 (d, J = 5.0 Hz, 2H), 3.04 (d, J = 0.6 Hz, 1H), 2.70 (d, J = 0.5 Hz,2H), 2.66 (d, J = 0.5 Hz, 2H), 1.46 (s, 2H), 1.34-1.24 (m, 18H), 0.89 (s, 3H); N2: 500 ml of anhydrous tetrahydrofuran was mixed with 0.1 mol of 1,3-dibromo-2-(bromomethyl)propane and 0.33 mol of 2-(dodecylamino)ethanol. 0.35 mol of triethylamine was added, and the mixture was reacted at 60 °C for 12 h. After cooling to room temperature, the mixture was washed three times with 200 ml of saturated brine each time, dried over 20 g of anhydrous magnesium sulfate for 2 h, filtered, and distilled under reduced pressure at 40 °C for 2 h to obtain 2,2'-((2-((dodecyl(2-hydroxyethyl)amino)methyl)propane-1,3-diyl)bis(dodecylazadiyl))bis(ethanol); the reaction equation is shown below:

[0023] Its 1H NMR data are as follows: 1 H NMR (400 MHz, DMSO-d6) δ 3.89 (t, J = 5.0 Hz,3H), 3.49 (d, J = 5.0 Hz, 6H), 2.60 (s, 6H), 2.49 (s, 6H), 2.46-2.34 (m, 6H),1.63 (s, 1H), 1.50 (s, 6H), 1.33-1.25 (m, 54H), 0.89 (s, 9H); N3: 500 ml of 70 wt% ethanol aqueous solution was mixed with 0.1 mol of 2,2'-((2-((dodecyl(2-hydroxyethyl)amino)methyl)propane-1,3-diyl)bis(dodecylazadiyl))bis(ethanol) and 0.305 mol of sodium 3-chloropropane-1-sulfonate. The mixture was stirred and heated to reflux for 48 h. After cooling to room temperature, it was distilled under reduced pressure at 40 °C for 3 h. The mixture was recrystallized three times with 400 ml of ethyl acetate / anhydrous ethanol (ethyl acetate / anhydrous ethanol V:V = 8:2). The mixture was then dried under vacuum at 60 °C for 12 h to obtain 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammonium)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium))bis(propane-1-sulfonate). The reaction equation is shown below:

[0024] Its 1H NMR data are as follows: 1H NMR (400 MHz, DMSO-d6) δ 5.07 (t, J = 5.0 Hz,3H), 3.72-3.57 (m, 6H), 3.53 (s, 1H), 3.45 (s, 6H), 3.44-3.28 (m, 18H), 2.79(s, 6H), 2.30-2.07 (m, 6H), 1.87-1.72 (m, 6H), 1.41 (s, 6H), 1.35-1.24 (m, 48H), 0.89 (s, 9H).

[0025] Example 2 Preparation of the accelerator: S1: Under nitrogen protection and in an ice bath, 200 ml of anhydrous acetonitrile was mixed with 0.1 mol cyanuric chloride and 0.105 mol dopamine. Then, 0.2 mol N,N-diisopropylethylamine was added, and the mixture was reacted for 3 h. 300 ml of 0.1 M hydrochloric acid was added, and the mixture was stirred thoroughly before filtration. The filter cake was washed with deionized water until neutral and dried under vacuum at 60 °C for 8 h to obtain intermediate 1. Its 1H NMR spectrum data are as follows: 1 HNMR (400 MHz, Chloroform- d ) δ 6.73-6.62 (m, 3H), 6.25 (s, 1H), 6.14 (s, 1H), 5.65 (d, J = 0.7 Hz, 1H), 3.68 (d, J = 0.5 Hz, 2H), 2.88 (t, J = 1.0 Hz, 2H); S2: Under nitrogen protection, 300 ml of anhydrous acetonitrile was mixed with 0.1 mol of intermediate 1 and 0.105 mol of 4-amino-2,2,6,6-tetramethylpiperidine-1-oxo radicals. Then, 0.2 mol of N,N-diisopropylethylamine was added, and the mixture was reacted at 25 °C for 8 h. Finally, 400 ml of 5 wt% acetic acid aqueous solution was added, and the mixture was stirred thoroughly before filtration. The filter cake was washed with deionized water until neutral and dried under vacuum at 60 °C for 8 h to obtain intermediate 2. Its 1H NMR spectrum data are as follows: 1 H NMR (300 MHz, Chloroform- d) δ 6.76-6.59 (m,3H), 6.25 (s, 1H), 6.22-6.11 (m, 2H), 5.75 (t, J = 0.5 Hz, 1H), 4.33 (d, J =0.5 Hz, 1H), 3.67 (d, J = 0.5 Hz, 2H), 2.88 (t, J = 1.0 Hz, 2H), 1.44 (s, 4H), 1.17 (d, J = 15.0 Hz, 12H); S3: Under nitrogen protection, 300 ml of a DMF / water mixed solution (DMF to water volume ratio of 19:1) was mixed with 0.1 mol of intermediate 2 and 0.11 mol of 5-aminovaleric acid. Then, 0.2 mol of N,N-diisopropylethylamine was added, and the mixture was reacted at 70 °C for 10 h. Next, 400 ml of 5 wt% acetic acid aqueous solution was added, and the mixture was stirred thoroughly before filtration. The filter cake was washed with deionized water until neutral and then dried under vacuum at 65 °C for 10 h to obtain intermediate 3. Its 1H NMR spectrum data are as follows: 1 H NMR (300 MHz, Chloroform- d ) δ 11.48 (s, 1H), 6.74-6.62 (m, 3H), 6.25 (s, 1H), 6.14 (s, 1H), 5.64-5.57 (m, 2H), 5.42 (t, J= 0.5 Hz, 1H), 4.32 (d, J = 0.5 Hz, 1H), 3.68 (d, J = 0.5 Hz, 2H), 3.50 (d, J= 0.6 Hz, 2H), 2.88 (t, J = 1.0 Hz, 2H), 2.25 (s, 2H), 1.93 (s, 2H), 1.69 (s,2H), 1.61 (s, 2H), 1.44 (s, 2H), 1.17 (d, J = 15.0 Hz, 12H); S4: Mix 40 ml of acetic anhydride, 13 ml of pyridine, and 0.31 mol of intermediate 3. Stir the mixture at room temperature for 4 h in the dark. Distill under reduced pressure at 50 °C for 3 h to obtain a pale yellow oily liquid. Add 600 ml of deionized water, allow to stand to precipitate, filter, wash the filter cake with ice water (3 × 500 ml), and air dry at room temperature for 2 h. Recrystallize with 600 ml of ethyl acetate / n-hexane (ethyl acetate / n-hexane V:V = 1:5), and dry under vacuum at 60 °C for 12 h to obtain acetylated intermediate 3. Mix 1500 ml of anhydrous DMF with acetylated intermediate 3, 0.1 mol of dicyclohexylcarbodiimide, and 0.02 mol of 4-dimethylaminopyridine. Add 0.1 mol of... 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammonium)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium))bis(propane-1-sulfonate) was reacted at 50°C for 12 h, cooled to room temperature, and 200 ml of saturated sodium bicarbonate solution was added and stirred for 30 min. Then, 400 ml of 20 wt% ammonia in methanol solution was added, and the reaction was carried out at room temperature for 12 h. The mixture was then distilled under reduced pressure at 40°C for 3 h to obtain an oily substance. 1800 ml of cold diethyl ether was added, and the mixture was stirred to precipitate the precipitate. The precipitate was filtered, washed with ice water (3 × 800 ml), and dried naturally at room temperature for 2 h. It was recrystallized from 1000 ml of ethyl acetate / n-hexane (ethyl acetate / n-hexane V:V = 1:5) and dried under vacuum at 60°C for 12 h to obtain the promoter. Its proton NMR spectrum is shown below. Figure 1 As shown, the proton NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d) δ6.75-6.63 (m, 9H), 6.25 (s, 3H), 6.14 (s, 3H), 5.60 (dd, J = 1.6, 0.6 Hz, 6H), 5.42 (d, J = 0.6 Hz, 3H), 4.40 (s, 6H), 4.32 (d, J = 0.6 Hz, 3H), 3.70-3.62 (m, 12H), 3.53-3.43 (m, 19H), 3.38 (s, 6H), 2.93 (s, 6H), 2.88 (t, J =1.0 Hz, 6H), 2.33 (s, 6H), 2.22 (d, J = 12.4 Hz, 3H), 2.07 (d, J = 12.4 Hz, 3H), 1.93 (s, 6H), 1.79 (s, 6H), 1.68 (s, 6H), 1.63 (s, 6H), 1.43 (d, J = 5.9Hz, 12H), 1.36-1.25 (m, 48H), 1.20 (s, 18H), 1.15 (s, 18H), 0.90 (s, 9H).

[0026] Example 3 Preparation of the accelerator: S1: Under nitrogen protection and in an ice bath, 200 ml of anhydrous acetonitrile was mixed with 0.1 mol of cyanuric chloride and 0.108 mol of dopamine. 0.2 mol of N,N-diisopropylethylamine was added, and the mixture was reacted for 3 h. 300 ml of 0.1 M hydrochloric acid was added, and the mixture was stirred thoroughly and then filtered. The filter cake was washed with deionized water until neutral and dried under vacuum at 60 °C for 8 h to obtain intermediate 1. S2: Under nitrogen protection, 300 ml of anhydrous acetonitrile was mixed with 0.1 mol of intermediate 1 and 0.108 mol of 4-amino-2,2,6,6-tetramethylpiperidine-1-oxy free radical. 0.2 mol of N,N-diisopropylethylamine was added, and the mixture was reacted at 25 °C for 7 h. 400 ml of 5 wt% acetic acid aqueous solution was added, and the mixture was stirred thoroughly and filtered. The filter cake was washed with deionized water until neutral and dried under vacuum at 60 °C for 8 h to obtain intermediate 2. S3: Under nitrogen protection, 300 ml of DMF / water mixed solution (DMF to water volume ratio of 19:1) was mixed with 0.1 mol of intermediate 2 and 0.115 mol of 5-aminovaleric acid. 0.2 mol of N,N-diisopropylethylamine was added, and the mixture was reacted at 75 °C for 9 h. 400 ml of 5 wt% acetic acid aqueous solution was added, and the mixture was stirred thoroughly before filtration. The filter cake was washed with deionized water until neutral and dried under vacuum at 65 °C for 10 h to obtain intermediate 3. S4: Mix 40 ml of acetic anhydride, 13 ml of pyridine, and 0.315 mol of intermediate 3. Stir the mixture at room temperature for 4 h under light-protected conditions. Distill under reduced pressure at 50 °C for 3 h to obtain a pale yellow oily liquid. Add 600 ml of deionized water, allow to stand to precipitate, filter, wash the filter cake with ice water (3 × 500 ml), and air dry at room temperature for 2 h. Recrystallize with 600 ml of ethyl acetate / n-hexane (ethyl acetate / n-hexane V:V = 1:5), and dry under vacuum at 60 °C for 12 h to obtain acetylated intermediate 3. Mix 1500 ml of anhydrous DMF with acetylated intermediate 3, 0.1 mol of dicyclohexylcarbodiimide, and 0.02 mol of 4-dimethylaminopyridine. Add 0.1 mol of... 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammonium)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium))bis(propane-1-sulfonate) was reacted at 55°C for 11 h, cooled to room temperature, and 200 ml of saturated sodium bicarbonate solution was added and stirred for 30 min. Then, 400 ml of 20 wt% ammonia in methanol solution was added, and the reaction was carried out at room temperature for 12 h. The mixture was then distilled under reduced pressure at 40°C for 3 h to obtain an oily substance. 1800 ml of cold diethyl ether was added, and the mixture was stirred to precipitate the precipitate. The precipitate was filtered, washed with ice water (3 × 800 ml), and dried naturally at room temperature for 2 h. The precipitate was recrystallized from 1000 ml of ethyl acetate / n-hexane (ethyl acetate / n-hexane V:V = 1:5) and dried under vacuum at 60°C for 12 h to obtain the accelerator.

[0027] Example 4: Preparation of the accelerator: S1: Under nitrogen protection and in an ice bath, 200 ml of anhydrous acetonitrile was mixed with 0.1 mol of cyanuric chloride and 0.11 mol of dopamine. 0.2 mol of N,N-diisopropylethylamine was added, and the mixture was reacted for 3 h. 300 ml of 0.1 M hydrochloric acid was added, and the mixture was stirred thoroughly and filtered. The filter cake was washed with deionized water until neutral and dried under vacuum at 60 °C for 8 h to obtain intermediate 1. S2: Under nitrogen protection, 300 ml of anhydrous acetonitrile was mixed with 0.1 mol of intermediate 1 and 0.11 mol of 4-amino-2,2,6,6-tetramethylpiperidine-1-oxy free radical. 0.2 mol of N,N-diisopropylethylamine was added, and the mixture was reacted at 30 °C for 6 h. 400 ml of 5 wt% acetic acid aqueous solution was added, and the mixture was stirred thoroughly and filtered. The filter cake was washed with deionized water until neutral and dried under vacuum at 60 °C for 8 h to obtain intermediate 2. S3: Under nitrogen protection, 300 ml of DMF / water mixed solution (DMF to water volume ratio of 19:1) was mixed with 0.1 mol of intermediate 2 and 0.12 mol of 5-aminovaleric acid. 0.2 mol of N,N-diisopropylethylamine was added, and the mixture was reacted at 80 °C for 8 h. 400 ml of 5 wt% acetic acid aqueous solution was added, and the mixture was stirred thoroughly and filtered. The filter cake was washed with deionized water until neutral and dried under vacuum at 65 °C for 10 h to obtain intermediate 3. S4: Mix 40 ml of acetic anhydride, 13 ml of pyridine, and 0.32 mol of intermediate 3. Stir the mixture at room temperature for 4 h in the dark. Distill under reduced pressure at 50 °C for 3 h to obtain a pale yellow oily liquid. Add 1000 ml of deionized water, allow to stand to precipitate, filter, wash the filter cake with ice water (3 × 500 ml), and air dry at room temperature for 2 h. Recrystallize with 600 ml of ethyl acetate / n-hexane (ethyl acetate / n-hexane V:V = 1:5), and dry under vacuum at 60 °C for 12 h to obtain acetylated intermediate 3. Mix 1500 ml of anhydrous DMF with acetylated intermediate 3, 0.1 mol of dicyclohexylcarbodiimide, and 0.02 mol of 4-dimethylaminopyridine. Add 0.1 mol of... 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammonium)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium))bis(propane-1-sulfonate) was reacted at 60°C for 10 h, cooled to room temperature, and 200 ml of saturated sodium bicarbonate solution was added and stirred for 30 min. Then, 400 ml of 20 wt% ammonia in methanol solution was added, and the reaction was carried out at room temperature for 12 h. The mixture was then distilled under reduced pressure at 40°C for 3 h to obtain an oily substance. 1800 ml of cold diethyl ether was added, and the mixture was stirred to precipitate the precipitate. The precipitate was filtered, washed with ice water (3 × 800 ml), and dried naturally at room temperature for 2 h. The precipitate was recrystallized from 1000 ml of ethyl acetate / n-hexane (ethyl acetate / n-hexane V:V = 1:5) and dried under vacuum at 60°C for 12 h to obtain the accelerator.

[0028] Example 5: Preparation of a novel composite synergistic additive for wet flue gas desulfurization: (1) Weigh the following by weight: 15g organic acid (benzoic acid), 10g organic salt (sodium acetate), 5g inorganic salt (magnesium sulfate), 4g wetting agent (sodium dodecylbenzenesulfonate), 5g hygroscopic agent (magnesium chloride), and 5g accelerator (prepared in Example 2); (2) At room temperature, add the above materials to the mixer and stir at 300 rpm for 20 min to mix evenly; add the mixed materials to a planetary ball mill, using grinding balls with a diameter of 5 mm and 3 mm, with a weight ratio of 5 mm grinding balls to 3 mm grinding balls of 2:1 and a ball-to-material ratio of 15:1, and grind at 500 rpm for 30 min to obtain the new type of wet flue gas desulfurization composite additive.

[0029] Example 6: Preparation of a novel composite synergistic additive for wet flue gas desulfurization: (1) Weigh the following by weight: 20g of organic acid (adipic acid), 15g of organic salt (sodium citrate), 8g of inorganic salt (sodium sulfate), 4.5g of wetting agent (sodium dodecylbenzenesulfonate), 6.5g of hygroscopic agent (magnesium chloride), and 10g of accelerator (prepared in Example 3); (2) At room temperature, add the above materials to the mixer and stir at 300 rpm for 20 min to mix evenly; add the mixed materials to a planetary ball mill, using grinding balls with a diameter of 5 mm and 3 mm, with a weight ratio of 5 mm grinding balls to 3 mm grinding balls of 2:1 and a ball-to-material ratio of 15:1, and grind at 500 rpm for 30 min to obtain the new type of wet flue gas desulfurization composite additive.

[0030] Example 7: Preparation of a novel composite synergistic additive for wet flue gas desulfurization: (1) Weigh the following by weight: 25g organic acid (benzoic acid), 20g organic salt (sodium citrate), 10g inorganic salt (magnesium sulfate), 5g wetting agent (sodium dodecylbenzenesulfonate), 8g hygroscopic agent (magnesium chloride), and 15g accelerator (prepared in Example 4); (2) At room temperature, add the above materials to the mixer and stir at 300 rpm for 20 min to mix evenly; add the mixed materials to a planetary ball mill, using grinding balls with a diameter of 5 mm and 3 mm, with a weight ratio of 5 mm grinding balls to 3 mm grinding balls of 2:1 and a ball-to-material ratio of 15:1, and grind at 500 rpm for 30 min to obtain the new type of wet flue gas desulfurization composite additive.

[0031] Comparative Example 1 The raw material composition and preparation method of the novel wet flue gas desulfurization composite synergist are basically the same as those in Example 6, except that the accelerator is replaced with an equal weight of the accelerator prepared by the following method: The preparation method of the accelerator is basically the same as that in Example 3, except that the dopamine in step S1 is replaced with an equimolar amount of p-hydroxyphenylethylamine.

[0032] Comparative Example 2 The raw material composition and preparation method of the novel wet flue gas desulfurization composite synergist are basically the same as those in Example 6, except that the accelerator is replaced with an equal weight of the accelerator prepared by the following method: The preparation method of the accelerator is basically the same as that in Example 3, except that the 4-amino-2,2,6,6-tetramethylpiperidine-1-oxy radical in step S2 is replaced with an equimolar amount of 2,2,6,6-tetramethyl-4-aminopiperidine.

[0033] Comparative Example 3 The raw material composition and preparation method of the novel wet flue gas desulfurization composite synergist are basically the same as those in Example 6, except that the accelerator is replaced with an equal weight of the accelerator prepared by the following method: The preparation method of the accelerator is basically the same as that in Example 3, except that 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammonium)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium))bis(propane-1-sulfonate) in step S4 is replaced with an equimolar amount of 3,3'-propane-1,3-diylbis(dodecyl(2-hydroxyethyl)ammoniumdiyl)bis(propane-1-sulfonate); The preparation method of 3,3'-propane-1,3-diylbis(dodecyl(2-hydroxyethyl)ammonium diyl)bis(propane-1-sulfonate) is as follows: N1: Under nitrogen protection, 150 ml of anhydrous tetrahydrofuran was mixed with 0.105 mol of dodecylamine and stirred until homogeneous. 0.1 mol of 2-chloroethanol was slowly added dropwise. After the addition was completed in 10 min, 0.15 mol of triethylamine was added. The mixture was reacted at 50 °C for 5 h. After cooling to room temperature, the mixture was washed three times with saturated brine (80 ml each time), dried with 10 g of anhydrous magnesium sulfate for 2 h, filtered, and distilled under reduced pressure at 40 °C for 2 h to obtain 2-(dodecylamino)ethanol. N2: Mix 500 ml of anhydrous tetrahydrofuran with 0.1 mol of 1,3-dibromopropane and 0.21 mol of 2-(dodecylamino)ethanol, add 0.25 mol of triethylamine, react at 60 °C for 12 h, cool to room temperature, wash three times with saturated brine (200 ml each time), dry with 20 g of anhydrous magnesium sulfate for 2 h, filter, and distill under reduced pressure at 40 °C for 2 h to obtain intermediate A; N3: Mix 500 ml of 70 wt% ethanol aqueous solution with 0.1 mol of intermediate A and 0.205 mol of sodium 3-chloropropane-1-sulfonate, heat to reflux, react for 48 h, cool to room temperature, distill under reduced pressure at 40 °C for 3 h, recrystallize three times with 400 ml of ethyl acetate / anhydrous ethanol (ethyl acetate / anhydrous ethanol V:V=8:2), and dry under vacuum at 60 °C for 12 h to obtain 3,3'-propane-1,3-diylbis(dodecyl(2-hydroxyethyl)ammonium diyl)bis(propane-1-sulfonate).

[0034] Comparative Example 4 The raw material composition and preparation method of the novel wet flue gas desulfurization composite synergist are basically the same as those in Example 6, except that the accelerator is replaced with an equal weight of the accelerator prepared by the following method: The preparation method of the accelerator is basically the same as that in Example 3, except that 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammonium)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium))bis(propane-1-sulfonate) in step S4 is replaced with an equimolar amount of 3,3'-((2,2-bis((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammoniummethyl))propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammoniumdiyl))bis(propane-1-sulfonate); The preparation method of 3,3'-((2,2-bis((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammoniummethyl))propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammoniumdiyl))bis(propane-1-sulfonate) is as follows: N1: Under nitrogen protection, 150 ml of anhydrous tetrahydrofuran was mixed with 0.105 mol of dodecylamine and stirred until homogeneous. 0.1 mol of 2-chloroethanol was slowly added dropwise. After the addition was completed in 10 min, 0.15 mol of triethylamine was added. The mixture was reacted at 50 °C for 5 h. After cooling to room temperature, the mixture was washed three times with saturated brine (80 ml each time), dried with 10 g of anhydrous magnesium sulfate for 2 h, filtered, and distilled under reduced pressure at 40 °C for 2 h to obtain 2-(dodecylamino)ethanol. N2: Mix 500 ml of anhydrous tetrahydrofuran with 0.1 mol tetrabromopentaerythritol and 0.41 mol 2-(dodecylamino)ethanol, add 0.45 mol triethylamine, react at 60 °C for 12 h, cool to room temperature, wash three times with saturated brine (200 ml each time), dry with 20 g anhydrous magnesium sulfate for 2 h, filter, and distill under reduced pressure at 40 °C for 2 h to obtain intermediate B; N3: Mix 500 ml of 70 wt% ethanol aqueous solution with 0.1 mol of intermediate B and 0.405 mol of sodium 3-chloropropane-1-sulfonate, heat to reflux, react for 48 h, cool to room temperature, distill under reduced pressure at 40 °C for 3 h, recrystallize three times with 400 ml of ethyl acetate / anhydrous ethanol (ethyl acetate / anhydrous ethanol V:V=8:2), and dry under vacuum at 60 °C for 12 h to obtain 3,3'-((2,2-bis((dodecyl(2-hydroxyethyl)(3-sulfonatepropyl)ammoniummethyl))propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammoniumdiyl))bis(propane-1-sulfonate).

[0035] Comparative Example 5 The raw material composition and preparation method of the novel wet flue gas desulfurization composite synergist are basically the same as those in Example 6, except that the accelerator is replaced with an equal weight of the accelerator prepared by the following method: The preparation method of the accelerator is basically the same as that in Example 3, except that 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammonium)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium))bis(propane-1-sulfonate) in step S4 is replaced with an equimolar amount of 3,3'-((2-(((2-hydroxyethyl)(pentyl)(3-sulfonylpropyl)ammoniummethyl)propane-1,3-diyl)bis((2-hydroxyethyl)(pentyl)ammoniumdiyl))bis(propane-1-sulfonate); The preparation method of 3,3'-((2-((2-hydroxyethyl)(pentyl)(3-sulfonylpropyl)ammoniummethyl)propane-1,3-diyl)bis((2-hydroxyethyl)(pentyl)ammoniumdiyl))bis(propane-1-sulfonate) is as follows: N1: Under nitrogen protection, 150 ml of anhydrous tetrahydrofuran was stirred and mixed with 0.105 mol of 1-aminopentane. 0.1 mol of 2-chloroethanol was slowly added dropwise. After the addition was completed in 10 min, 0.15 mol of triethylamine was added. The reaction was carried out at 50 °C for 5 h. After cooling to room temperature, the mixture was washed three times with saturated brine (80 ml each time), dried with 10 g of anhydrous magnesium sulfate for 2 h, filtered, and distilled under reduced pressure at 40 °C for 2 h to obtain intermediate C. N2: Mix 500 ml of anhydrous tetrahydrofuran with 0.1 mol of 1,3-dibromo-2-(bromomethyl)propane and 0.33 mol of intermediate C, add 0.35 mol of triethylamine, react at 60 °C for 12 h, cool to room temperature, wash three times with saturated brine (200 ml each time), dry with 20 g of anhydrous magnesium sulfate for 2 h, filter, and distill under reduced pressure at 40 °C for 2 h to obtain intermediate D; N3: Mix 500 ml of 70 wt% ethanol aqueous solution with 0.1 mol of intermediate D and 0.305 mol of sodium 3-chloropropane-1-sulfonate, heat to reflux, react for 48 h, cool to room temperature, distill under reduced pressure at 40 °C for 3 h, recrystallize three times with 400 ml of ethyl acetate / anhydrous ethanol (ethyl acetate / anhydrous ethanol V:V=8:2), and dry under vacuum at 60 °C for 12 h to obtain 3,3'-((2-((2-hydroxyethyl)(pentyl)(3-sulfonate propyl)ammonium methyl)propane-1,3-diyl)bis((2-hydroxyethyl)(pentyl)ammonium diyl))bis(propane-1-sulfonate).

[0036] The desulfurization composite synergistic additives prepared in Examples 5-7 and Comparative Examples 1-5 were subjected to limestone dissolution, calcium sulfite oxidation, and flue gas desulfurization tests. The results are shown in Table 1.

[0037] Limestone dissolution test: The desulfurization composite additives prepared in Examples 5-7 and Comparative Examples 1-5 were mixed evenly with 100 ml of 3 wt% limestone slurry (the content of the desulfurization composite additives was 1000 mg / L). The mixture was heated to 50℃ and titrated with 0.1 M HCl at a speed of 300 r / min. The pH value of the automatic titrator was set to 5.5. The amount of hydrochloric acid used after 1 h of titration was recorded. The limestone dissolution rate was calculated according to the formula X(t) = (c×v) / (2×m / Mn)×100% (where c is the concentration of HCl; v is the volume of hydrochloric acid consumed in 1 h; m is the total mass of calcium carbonate; Mn is the relative molecular mass of calcium carbonate).

[0038] Calcium sulfite oxidation test: The desulfurization composite synergist prepared in Examples 5-7 and Comparative Examples 1-5 was mixed evenly with 100 ml of 1 wt% CaSO3 (the content of the desulfurization composite synergist was 1000 mg / L), and 1 ml of 12M concentrated hydrochloric acid was added and mixed evenly. The experimental temperature was set at 50℃, the stirring speed at 300 r / min, and a mixed gas of N2, O2, and CO2 (N2, O2, CO2 ratio of 4:1:5) was introduced with a total flow rate of 0.2 L / min. The SO42- content in the solution was determined using an automatic potentiometric titrator equipped with a lead nitrate electrode. 2- The concentration, time 1 hour, according to the formula V(t) = (C t -C0) / t (where, C) t Calculate the oxidation rate of CaSO3 using the sulfate concentration at 1 hour (C0 is the initial sulfate concentration, and t is time).

[0039] Flue gas desulfurization test: The desulfurization composite synergist additives prepared in Examples 5-7 and Comparative Examples 1-5 were mixed evenly with 100 ml of 3 wt% limestone slurry (the content of the desulfurization composite synergist additive was 1000 mg / L). Under the conditions of 50℃ and 300 r / min, the initial pH of the slurry was adjusted to 5.5 using an automatic potentiometric titrator. The limestone slurry with added desulfurization composite synergist additive was added to the absorption tower, and 1 wt% SO2 / N2 standard gas (the balance gas was nitrogen) was introduced. The inlet SO2 concentration was measured to be 2200 ppm using a flue gas analyzer. After 1 hour, the SO2 concentration in the outlet flue gas was monitored. According to the formula б= (C0-C t ) / C0 (where C0 is the inlet SO2 concentration, C t Calculate the desulfurization efficiency by taking the SO2 concentration at the outlet at 1 hour as the value.

[0040] Table 1

[0041] As can be seen from the data in Table 1, the novel wet flue gas desulfurization composite additives prepared in Examples 5-7 of this application can effectively promote the dissolution of calcium carbonate and the oxidation of calcium sulfite, and have excellent desulfurization efficiency.

[0042] The novel wet flue gas desulfurization composite synergist prepared in this application exhibits good calcium carbonate solubility and calcium sulfite oxidation rate, resulting in high desulfurization efficiency. This is mainly due to the fact that the added accelerator has a multi-branched structure containing catechol groups, nitroxide radicals, quaternary ammonium salts, sulfonates, and long-chain alkyl groups. This structure maximizes the functional site density, avoids interference between individual groups, and improves the contact efficiency between each unit and the reaction interface. The catechol groups in the accelerator chelate Ca through ortho-hydroxyl groups. 2+ Disrupts the surface dissolution equilibrium of CaCO3, accelerating the dissolution of Ca. 2+ The release of calcium carbonate increases its solubility, thereby improving desulfurization efficiency. The quaternary ammonium salt in the accelerator enriches HSO3 through electrostatic attraction. - By increasing the concentration of local reactants near the catalytic site, nitric oxide radicals activate O2, thereby reducing HSO3. - Efficient oxidation to SO4 2- This process avoids calcium sulfite scaling. Simultaneously, sulfonate groups enhance hydrophilicity, while long-chain alkyl groups act as hydrophobic groups, adsorbing at the gas-liquid interface, reducing surface tension, and increasing gas-liquid surface activity. This enhances the O2 mass transfer capacity at the gas-liquid interface, allowing O2 to react with calcium sulfite more promptly and effectively. The synergistic effect of nitroxide radicals, quaternary ammonium salts, sulfonate groups, and long-chain alkyl groups increases the calcium sulfite oxidation rate, thereby improving desulfurization efficiency. In Comparative Example 4, the promoter used had a higher reaction site density, leading to a decrease in the efficiency of catechol chelation and nitroxide radical functional sites, a decrease in the interfacial adsorption and mass transfer capacity of surface-active groups, and a decrease in the overall molecular diffusion and reaction interface contact efficiency. This reduces the synergistic efficiency of various structures, resulting in a decrease in the final desulfurization efficiency.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. However, any modifications, alterations, and variations made by those skilled in the art without departing from the scope of the present invention based on the disclosed technical content are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A novel composite synergistic additive for wet flue gas desulfurization, characterized in that, The ingredients include the following parts by weight: 15-25 parts organic acid, 10-20 parts organic salt, 5-10 parts inorganic salt, 4-5 parts wetting agent, 5-8 parts hygroscopic agent, and 5-15 parts accelerator; The accelerator is prepared by the following method: S1: Cyanurium chloride reacts with dopamine to produce intermediate 1. S2: Intermediate 1 reacts with 4-amino-2,2,6,6-tetramethylpiperidine-1-oxo radical to generate intermediate 2. S3: Intermediate 2 reacts with 5-aminovaleric acid to generate intermediate 3. S4: Intermediate 3 reacts with 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammonium)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium))bis(propane-1-sulfonate) to give an accelerator.

2. The novel composite additive for wet flue gas desulfurization according to claim 1, characterized in that, In step S1, the molar ratio of cyanuric chloride to dopamine is 1:(1.05-1.1).

3. The novel composite additive for wet flue gas desulfurization according to claim 1, characterized in that, In step S2, the molar ratio of intermediate 1 to 4-amino-2,2,6,6-tetramethylpiperidine-1-oxy radical is 1:(1.05-1.1).

4. The novel composite additive for wet flue gas desulfurization according to claim 1, characterized in that, In step S3, the molar ratio of intermediate 2 to 5-aminovaleric acid is 1:(1.1-1.2).

5. The novel composite additive for wet flue gas desulfurization according to claim 1, characterized in that, In step S4, the molar ratio of intermediate 3 to 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonylpropyl)ammonium)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium))bis(propane-1-sulfonate) is 1:(3.1-3.2).

6. The novel composite additive for wet flue gas desulfurization according to claim 1, characterized in that, The organic acid is one of benzoic acid and adipic acid.

7. The novel composite additive for wet flue gas desulfurization according to claim 1, characterized in that, The organic salt is one of sodium acetate or sodium citrate.

8. The novel composite additive for wet flue gas desulfurization according to claim 1, characterized in that, The inorganic salt is either magnesium sulfate or sodium sulfate.

9. The novel composite additive for wet flue gas desulfurization according to claim 1, characterized in that, The wetting agent is sodium dodecylbenzenesulfonate; the hygroscopic agent is magnesium chloride.

10. A method for preparing a novel wet flue gas desulfurization composite synergist additive according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Weigh out the following by weight: 15-25 parts organic acid, 10-20 parts organic salt, 5-10 parts inorganic salt, 4-5 parts wetting agent, 5-8 parts hygroscopic agent, and 5-15 parts accelerator; (2) Mix the above materials, stir evenly, and grind them into powder in a planetary ball mill to obtain a new type of wet flue gas desulfurization composite additive.

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