A composite synergistic additive for wet flue gas desulfurization and a preparation method thereof

Abstract

The application discloses a kind of wet flue gas desulfurization composite synergistic additive and preparation method thereof, and relates to flue gas desulfurization technical field.The wet flue gas desulfurization composite synergistic additive includes the following weight fraction of raw materials: organic acid 15-25 parts, organic salt 10-20 parts, inorganic salt 5-10 parts, wetting agent 4-5 parts, hygroscopic agent 5-8 parts, accelerator 5-15 parts.The wet flue gas desulfurization composite synergistic additive prepared by the application has good calcium carbonate dissolution rate and calcium sulfite oxidation rate, and the desulfurization efficiency is higher.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flue gas desulfurization technology, in particular to a wet flue gas desulfurization composite synergistic additive and a preparation method thereof. BACKGROUND

[0002] The wet flue gas desulfurization technology has become the core treatment process for flue gas of coal-fired power plants and other industrial furnaces due to its high desulfurization efficiency, reliable operation, and abundant resources of absorbents. However, in actual operation, this process still generally faces problems such as large SO2 gas-liquid mass transfer resistance, slow limestone dissolution rate, and difficult oxidation of intermediate product calcium sulfite, which leads to a series of problems such as low desulfurization efficiency, low limestone utilization rate, poor quality of by-products, system fouling and plugging, and high operation energy consumption. In order to overcome the above problems, adding a desulfurization synergistic additive has become an economical and effective technical means. However, the existing synergistic additives have problems such as poor synergy of components and unsatisfactory desulfurization effect.

[0003] The Chinese patent CN105664702A discloses a wet flue gas desulfurization composite synergistic additive and a preparation method thereof. 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; manganese chloride 2-10 parts. The preparation method of the above composite synergistic additive is as follows: adipic acid, nylon acid, sodium citrate, sodium sulfate, ferric sulfate, and manganese chloride are weighed according to the weight ratio of each component, and then mixed and stirred uniformly at normal temperature and pressure. The desulfurization composite synergistic additive in the present application is simple to prepare and has low cost, but its desulfurization efficiency is generally low. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application aims to provide a wet flue gas desulfurization composite synergistic additive and a preparation method thereof.

[0005] To achieve the above-mentioned purpose, the present application realizes the technical scheme as follows:

[0006] A wet flue gas desulfurization composite synergistic additive comprises the following raw materials by weight:

[0007] organic acid 15-25 parts, organic salt 10-20 parts, inorganic salt 5-10 parts, wetting agent 4-5 parts, hygroscopic agent 5-8 parts, and promoter 5-15 parts;

[0008] The promoter is prepared by the following method:

[0009] S1: tricyanogen chloride reacts with dopamine to generate an intermediate 1, and the reaction equation is as follows:

[0010]

[0011] S2: intermediate 1 reacts with 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl radical to generate intermediate 2, and the reaction equation is as follows:

[0012]

[0013] S3: intermediate 2 reacts with 5-aminovaleric acid to generate intermediate 3, and the reaction equation is as follows:

[0014]

[0015] S4: intermediate 3 reacts with 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonic acid propyl) ammonium) methyl) propane-1,3-diyl) bis(dodecyl(2-hydroxyethyl) ammonium)) bis(propane-1-sulfonate) to obtain the accelerator, and the reaction equation is as follows:

[0016]

[0017] In step S1, the molar ratio of the tricyanocyanide to dopamine is 1: (1.05-1.1).

[0018] In step S2, the molar ratio of the intermediate 1 to 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl radical is 1: (1.05-1.1).

[0019] In step S3, the molar ratio of the intermediate 2 to 5-aminovaleric acid is 1: (1.1-1.2).

[0020] In step S4, the molar ratio of the intermediate 3 to 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonic acid propyl) ammonium) methyl) propane-1,3-diyl) bis(dodecyl(2-hydroxyethyl) ammonium)) bis(propane-1-sulfonate) is 1: (3.1-3.2).

[0021] The organic acid is one of benzoic acid and adipic acid.

[0022] The organic salt is one of sodium acetate and sodium citrate.

[0023] The inorganic salt is one of magnesium sulfate and sodium sulfate.

[0024] The wetting agent is sodium dodecyl benzene sulfonate; and the moisture absorbent is magnesium chloride.

[0025] A preparation method of a wet flue gas desulfurization composite synergistic additive comprises the following steps:

[0026] (1) Weigh by weight parts: organic acid 15-25 parts, organic salt 10-20 parts, inorganic salt 5-10 parts, wetting agent 4-5 parts, hygroscopic agent 5-8 parts, and accelerator 5-15 parts;

[0027] (2) Mix the above materials, stir uniformly, add to the planetary ball mill and grind into powder, to obtain the wet flue gas desulfurization composite synergistic additive.

[0028] Due to the above technical scheme, the beneficial effects of the present application include:

[0029] The wet flue gas desulfurization composite synergistic additive prepared by the present application has good calcium carbonate dissolution rate and calcium sulfite oxidation rate, and high desulfurization efficiency. The accelerator added improves the calcium carbonate dissolution rate through the catechol group; the oxidation rate of calcium sulfite is improved through the synergistic effect of quaternary ammonium salt, nitrogen-oxygen free radical, sulfonate and long-chain alkyl group, and the desulfurization efficiency is significantly improved by the combined action of various structures. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The nuclear magnetic resonance hydrogen spectrum of the accelerator prepared in Example 2. DETAILED DESCRIPTION

[0031] The following will be further illustrated in combination with examples, but the present application is not limited to these examples.

[0032] Preparation of 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonic acid propyl) ammonium group) methyl) propane-1,3-diyl) bis(dodecyl(2-hydroxyethyl) ammonium group)) bis(propane-1-sulfonate) in Example 1:

[0033] N1: Under nitrogen protection, 150ml of anhydrous tetrahydrofuran was stirred and mixed with 0.105mol of dodecylamine, 0.1mol of 2-chloroethanol was slowly added dropwise, 10min dropwise, 0.15mol of triethylamine was added, 50℃ reaction for 5h, cooled to room temperature, washed with saturated brine three times (80ml each time), dried with 10g of anhydrous magnesium sulfate for 2h, filtered, 40℃ reduced pressure distillation for 2h, to obtain 2-(dodecylamino) ethanol; the reaction equation is as follows:

[0034]

[0035] The nuclear magnetic hydrogen spectrum data are as follows: 1H 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);

[0036] N2: 500 ml of anhydrous tetrahydrofuran was stirred with 0.1 mol of 1,3-dibromo-2- (bromomethyl) propane, 0.33 mol of 2- (dodecylamino) ethanol, 0.35 mol of triethylamine was added, and reacted at 60°C for 12h, cooled to room temperature, washed with saturated brine three times (200 ml each time), dried with 20 g of anhydrous magnesium sulfate for 2h, filtered, distilled at 40°C under reduced pressure for 2h to obtain 2,2'- ((2- ((dodecyl (2-hydroxyethyl) amino) methyl) propane-1,3-diyl) bis (dodecylazadiyl)) bis (ethanol) ; its reaction equation is as follows:

[0037]

[0038] Its nuclear magnetic resonance hydrogen spectrum 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);

[0039] N3: 500 ml of 70 wt% ethanol aqueous solution was stirred with 0.1 mol of 2,2'-((2-((dodecyl(2-hydroxyethyl)amino)methyl)propane-1,3-diyl)bis(dodecylazadiyl))bis(ethanol), 0.305 mol of 3-chloropropane-1-sulfonic acid sodium, and the mixture was uniformly stirred, heated to reflux, and reacted for 48 h. The reaction mixture was cooled to room temperature, distilled at 40 °C under reduced pressure for 3 h, recrystallized with 400 ml of ethyl acetate / anhydrous ethanol (ethyl acetate / anhydrous ethanol V:V = 8:2) for three times, and dried at 60 °C under vacuum for 12 h to obtain 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonic acid propyl)ammoniumyl)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammoniumyl))bis(propane-1-sulfonate). The reaction equation is shown as follows:

[0040]

[0041] The nuclear magnetic resonance hydrogen spectrum data are as follows: 1 H 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)。

[0042] Example 2 Preparation of the promoter:

[0043] S1: 200 ml of anhydrous acetonitrile was stirred with 0.1 mol of cyanuric chloride and 0.105 mol of dopamine under nitrogen protection, and the mixture was uniformly stirred in an ice bath. 0.2 mol of N,N-diisopropylethylamine was added, and the reaction was carried out for 3 h. 300 ml of 0.1 M hydrochloric acid was added, and after being stirred thoroughly, the filter cake was washed with deionized water until neutral, and dried at 60 °C under vacuum for 8 h to obtain the intermediate 1. The nuclear magnetic resonance hydrogen 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);

[0044] S2: 300 ml of anhydrous acetonitrile was stirred and mixed with 0.1 mol of intermediate 1, 0.105 mol of 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl radical, and 0.2 mol of N,N-diisopropyl ethylamine under nitrogen protection, and reacted at 25°C for 8 h. Then 400 ml of 5 wt% acetic acid aqueous solution was added, and after sufficient stirring, filtration was performed. The filter cake was washed with deionized water until neutral, and vacuum dried at 60°C for 8 h to obtain intermediate 2. The nuclear magnetic resonance hydrogen spectrum data thereof 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);

[0045] S3: 300 ml of a DMF / water mixed solution (the volume ratio of DMF to water is 19:1) was stirred and mixed with 0.1 mol of intermediate 2, 0.11 mol of 5-aminovaleric acid, and 0.2 mol of N,N-diisopropyl ethylamine under nitrogen protection, and reacted at 70°C for 10 h. Then 400 ml of 5 wt% acetic acid aqueous solution was added, and after sufficient stirring, filtration was performed. The filter cake was washed with deionized water until neutral, and vacuum dried at 65°C for 10 h to obtain intermediate 3. The nuclear magnetic resonance hydrogen spectrum data thereof 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);

[0046] 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) δ 6.75-6.63 (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 = 5.9 Hz, 12H), 1.36-1.25 (m, 48H), 1.20 (s, 18H), 1.15 (s, 18H), 0.90 (s, 9H).

[0047] Example 3 Preparation of the accelerator:

[0048] S1: Under nitrogen protection, 200 ml of anhydrous acetonitrile was stirred and mixed with 0.1 mol of cyanuric chloride, 0.108 mol of dopamine, 0.2 mol of N,N-diisopropyl ethylamine was added, and the reaction was carried out for 3 h. 300 ml of 0.1 M hydrochloric acid was added, and after stirring, the filter cake was washed with deionized water until neutral, and vacuum dried at 60°C for 8 h to obtain intermediate 1;

[0049] S2: Under nitrogen protection, 300 ml of anhydrous acetonitrile was stirred and mixed with 0.1 mol of intermediate 1, 0.108 mol of 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl, 0.2 mol of N,N-diisopropyl ethylamine was added, and the reaction was carried out at 25°C for 7 h. 400 ml of 5 wt% acetic acid aqueous solution was added, and after stirring, the filter cake was washed with deionized water until neutral, and vacuum dried at 60°C for 8 h to obtain intermediate 2;

[0050] S3: 300 ml of a mixed solution of DMF / water (volume ratio of DMF to water is 19:1) was stirred and mixed with 0.1 mol of intermediate 2 and 0.115 mol of 5-aminovaleric acid under nitrogen protection, 0.2 mol of N,N-diisopropyl ethylamine was added, and the reaction was carried out at 75°C for 9 h. Then 400 ml of 5 wt% acetic acid aqueous solution was added, and after sufficient stirring, filtration was performed. The filter cake was washed with deionized water until neutral, and vacuum drying was carried out at 65°C for 10 h to obtain intermediate 3;

[0051] S4: 40 ml of acetic anhydride and 13 ml of pyridine were mixed with 0.315 mol of intermediate 3, and the reaction was carried out at room temperature for 4 h under light-proof condition. Then 3 h of distillation was carried out at 50°C under reduced pressure to obtain a yellowish oily liquid. Then 600 ml of deionized water was added, and the precipitate was separated by standing. Filtration was performed, and the filter cake was washed with ice water (3 x 500 ml) and naturally dried at room temperature for 2 h. Recrystallization was performed with 600 ml of ethyl acetate / n-hexane (volume ratio of ethyl acetate to n-hexane is 1:5), and vacuum drying was carried out at 60°C for 12 h to obtain acetylated intermediate 3. Then 1500 ml of anhydrous DMF was stirred and mixed with acetylated intermediate 3, 0.1 mol of dicyclohexyl carbodiimide, and 0.02 mol of 4-dimethylamino pyridine. Then 0.1 mol of 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonic acid propyl) ammonium) methyl) propane-1,3-diyl) bis(dodecyl(2-hydroxyethyl) ammonium)) bis(propane-1-sulfonate) was added, and the reaction was carried out at 55°C for 11 h. Then the reaction was cooled to room temperature, 200 ml of saturated sodium bicarbonate solution was added, and stirring was carried out for 30 min. Then 400 ml of 20 wt% ammonia methanol solution was added, and the reaction was carried out at room temperature for 12 h. Then 3 h of distillation was carried out at 40°C under reduced pressure to obtain an oily substance. Then 1800 ml of cold ether was added, and the precipitate was separated by stirring. Filtration was performed, and the filter cake was washed with ice water (3 x 800 ml) and naturally dried at room temperature for 2 h. Recrystallization was performed with 1000 ml of ethyl acetate / n-hexane (volume ratio of ethyl acetate to n-hexane is 1:5), and vacuum drying was carried out at 60°C for 12 h to obtain the accelerator.

[0052] Example 4: Preparation of the accelerator:

[0053] S1: 200 ml of anhydrous acetonitrile was stirred and mixed with 0.1 mol of cyanuric chloride and 0.11 mol of dopamine under nitrogen protection, and the reaction was carried out at 0°C for 3 h. Then 300 ml of 0.1M hydrochloric acid was added, and after sufficient stirring, filtration was performed. The filter cake was washed with deionized water until neutral, and vacuum drying was carried out at 60°C for 8 h to obtain intermediate 1.

[0054] S2: 300 ml of anhydrous acetonitrile was stirred and mixed with 0.1 mol of intermediate 1, 0.11 mol of 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl, and 0.2 mol of N,N-diisopropyl ethylamine under nitrogen protection, and reacted at 30°C for 6 h. Then, 400 ml of 5 wt% acetic acid aqueous solution was added, and after sufficient stirring, filtration was performed. The filter cake was washed with deionized water until neutral, and vacuum dried at 60°C for 8 h to obtain intermediate 2;

[0055] S3: 300 ml of a DMF / water mixed solution (volume ratio of DMF to water was 19:1) was stirred and mixed with 0.1 mol of intermediate 2, 0.12 mol of 5-aminovaleric acid, and 0.2 mol of N,N-diisopropyl ethylamine under nitrogen protection, and reacted at 80°C for 8 h. Then, 400 ml of 5 wt% acetic acid aqueous solution was added, and after sufficient stirring, filtration was performed. The filter cake was washed with deionized water until neutral, and vacuum dried at 65°C for 10 h to obtain intermediate 3.

[0056] S4: 40 ml of acetic anhydride and 13 ml of pyridine were mixed with 0.32 mol of intermediate 3, and stirred and reacted at room temperature for 4 h under light shielding condition. Then, 1000 ml of deionized water was added, and a precipitate was separated by standing. The precipitate was filtered, washed with ice water (3 x 500 ml), and naturally dried at room temperature for 2 h. Then, recrystallization was performed using 600 ml of ethyl acetate / n-hexane (volume ratio of ethyl acetate to n-hexane was 1:5), and vacuum dried at 60°C for 12 h to obtain acetylated intermediate 3. Then, 1500 ml of anhydrous DMF was stirred and mixed with acetylated intermediate 3, 0.1 mol of dicyclohexyl carbodiimide, and 0.02 mol of 4-dimethylamino pyridine. Then, 0.1 mol of 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonic acid propyl)ammoniumyl)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammoniumyl))bis(propane-1-sulfonate) was added, and reacted at 60°C for 10 h. Then, the reaction solution was 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 methanol solution was added, and reacted at room temperature for 12 h. Then, oil was obtained by distillation at 40°C under reduced pressure for 3 h. Then, 1800 ml of cold ether was added, and a precipitate was separated by stirring. The precipitate was filtered, washed with ice water (3 x 800 ml), and naturally dried at room temperature for 2 h. Then, recrystallization was performed using 1000 ml of ethyl acetate / n-hexane (volume ratio of ethyl acetate to n-hexane was 1:5), and vacuum dried at 60°C for 12 h to obtain the accelerator.

[0057] Example 5: Preparation of a composite synergistic additive for wet flue gas desulfurization

[0058] (1) Weighing by weight: organic acid (benzoic acid) 15 g, organic salt (sodium acetate) 10 g, inorganic salt (magnesium sulfate) 5 g, wetting agent (sodium dodecyl benzene sulfonate) 4 g, moisture absorbent (magnesium chloride) 5 g, accelerator (prepared in Example 2) 5 g;

[0059] (2) At room temperature, the above materials are added to a stirrer, stirred at 300 rpm for 20 min, mixed uniformly; the mixed material is added to a planetary ball mill, 5 mm diameter grinding balls and 3 mm grinding balls are used, the weight ratio of 5 mm grinding balls to 3 mm grinding balls is 2:1, the ball-to-material ratio is 15:1, and the grinding is carried out at 500 rpm for 30 min, to obtain the wet flue gas desulfurization composite synergistic additive.

[0060] Example 6 Preparation of wet flue gas desulfurization composite synergistic additive:

[0061] (1) Weighing by weight: organic acid (adipic acid) 20 g, organic salt (sodium citrate) 15 g, inorganic salt (sodium sulfate) 8 g, wetting agent (sodium dodecyl benzene sulfonate) 4.5 g, moisture absorbent (magnesium chloride) 6.5 g, accelerator (prepared in Example 3) 10 g;

[0062] (2) At room temperature, the above materials are added to a stirrer, stirred at 300 rpm for 20 min, mixed uniformly; the mixed material is added to a planetary ball mill, 5 mm diameter grinding balls and 3 mm grinding balls are used, the weight ratio of 5 mm grinding balls to 3 mm grinding balls is 2:1, the ball-to-material ratio is 15:1, and the grinding is carried out at 500 rpm for 30 min, to obtain the wet flue gas desulfurization composite synergistic additive.

[0063] Example 7 Preparation of wet flue gas desulfurization composite synergistic additive:

[0064] (1) Weighing by weight: organic acid (benzoic acid) 25 g, organic salt (sodium citrate) 20 g, inorganic salt (magnesium sulfate) 10 g, wetting agent (sodium dodecyl benzene sulfonate) 5 g, moisture absorbent (magnesium chloride) 8 g, accelerator (prepared in Example 4) 15 g;

[0065] (2) At room temperature, the above materials are added to a stirrer, stirred at 300 rpm for 20 min, mixed uniformly; the mixed material is added to a planetary ball mill, 5 mm diameter grinding balls and 3 mm grinding balls are used, the weight ratio of 5 mm grinding balls to 3 mm grinding balls is 2:1, the ball-to-material ratio is 15:1, and the grinding is carried out at 500 rpm for 30 min, to obtain the wet flue gas desulfurization composite synergistic additive.

[0066] Comparative Example 1

[0067] The raw material composition and preparation method of the wet flue gas desulfurization composite synergistic additive are basically the same as those in Embodiment 6, except that the promoter is replaced with an equal weight of a promoter prepared by the following method:

[0068] The preparation method of the promoter is basically the same as that in Embodiment 3, except that the dopamine in step S1 is replaced with an equal molar amount of p-hydroxyphenethylamine.

[0069] Comparative Example 2

[0070] The raw material composition and preparation method of the wet flue gas desulfurization composite synergistic additive are basically the same as those in Embodiment 6, except that the promoter is replaced with an equal weight of a promoter prepared by the following method:

[0071] The preparation method of the promoter is basically the same as that in Embodiment 3, except that the 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl radical in step S2 is replaced with an equal molar amount of 2,2,6,6-tetramethyl-4-aminopiperidine.

[0072] Comparative Example 3

[0073] The raw material composition and preparation method of the wet flue gas desulfurization composite synergistic additive are basically the same as those in Embodiment 6, except that the promoter is replaced with an equal weight of a promoter prepared by the following method:

[0074] The preparation method of the promoter is basically the same as that in Embodiment 3, except that the 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonatopropyl)ammonio)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonio))bis(propane-1-sulfonate) in step S4 is replaced with an equal molar amount of 3,3'-propane-1,3-diylbis(dodecyl(2-hydroxyethyl)ammoniumdiyl)bis(propane-1-sulfonate);

[0075] The preparation method of 3,3'-propane-1,3-diylbis(dodecyl(2-hydroxyethyl)ammoniumdiyl)bis(propane-1-sulfonate) is as follows:

[0076] N1: Under nitrogen protection, 150 ml of anhydrous tetrahydrofuran is stirred and mixed with 0.105 mol of dodecylamine, 0.1 mol of 2-chloroethanol is slowly added dropwise, 10 min after dropping, 0.15 mol of triethylamine is added, 50°C reaction for 5h, cooling to room temperature, washing with saturated brine three times (80 ml each time), drying with 10 g of anhydrous magnesium sulfate for 2h, filtering, 40°C reduced pressure distillation for 2h, to obtain 2-(dodecylamino)ethanol;

[0077] N2: 500 ml of anhydrous tetrahydrofuran was stirred and mixed with 0.1 mol of 1,3-dibromopropane, 0.21 mol of 2-(dodecylamino)ethanol, 0.25 mol of triethylamine was added, and reacted at 60°C for 12 h. After cooling to room temperature, it was washed with saturated brine three times (200 ml each time), dried with 20 g of anhydrous magnesium sulfate for 2 h, filtered, and distilled under reduced pressure at 40°C for 2 h to obtain intermediate A;

[0078] N3: 500 ml of 70 wt% aqueous ethanol solution was stirred and mixed with 0.1 mol of intermediate A, 0.205 mol of 3-chloropropane-1-sulfonic acid sodium salt, and heated to reflux and reacted for 48 h. After cooling to room temperature, it was distilled under reduced pressure at 40°C for 3 h, recrystallized three times with 400 ml of ethyl acetate / anhydrous ethanol (ethyl acetate / anhydrous ethanol V:V=8:2), and dried at 60°C under vacuum for 12 h to obtain 3,3'-propane-1,3-diyl bis(dodecyl(2-hydroxyethyl)ammonium diyl) bis(propane-1-sulfonate).

[0079] Comparative Example 4

[0080] The raw material composition and preparation method of the wet flue gas desulfurization composite synergistic additive of Example 6 are basically the same, except that the promoter is replaced with an equal weight of a promoter prepared by the following method:

[0081] The preparation method of the promoter is basically the same as that of Example 3, except that 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonic acid propyl)ammoniumyl)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammoniumyl))bis(propane-1-sulfonate) in step S4 is replaced with an equal molar amount of 3,3'-((2,2-bis((dodecyl(2-hydroxyethyl)(3-sulfonic acid propyl)ammoniumyl methyl))propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium diyl))bis(propane-1-sulfonate);

[0082] The preparation method of 3,3'-((2,2-bis((dodecyl(2-hydroxyethyl)(3-sulfonic acid propyl)ammoniumyl methyl))propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium diyl))bis(propane-1-sulfonate) is as follows:

[0083] N1: 150 ml of anhydrous tetrahydrofuran was stirred and mixed with 0.105 mol of dodecylamine under nitrogen protection, 0.1 mol of 2-chloroethanol was slowly added dropwise, and the dropping was completed in 10 min, 0.15 mol of triethylamine was added, and reacted at 50°C for 5 h. After cooling to room temperature, it was washed with saturated brine three times (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;

[0084] N2: 500 ml of anhydrous tetrahydrofuran was stirred and mixed with 0.1 mol of tetrabromopentaerythritol, 0.41 mol of 2-(dodecylamino)ethanol, 0.45 mol of triethylamine was added, and reacted at 60°C for 12 h. After cooling to room temperature, it was washed with saturated brine three times (200 ml each time), dried with 20 g of anhydrous magnesium sulfate for 2 h, filtered, and distilled under reduced pressure at 40°C for 2 h to obtain intermediate B.

[0085] N3: 500 ml of 70 wt% aqueous ethanol solution was stirred and mixed with 0.1 mol of intermediate B, 0.405 mol of 3-chloropropane-1-sulfonic acid sodium salt, and warmed to reflux and reacted for 48 h. After cooling to room temperature, it was distilled under reduced pressure at 40°C for 3 h, recrystallized three times with 400 ml of ethyl acetate / anhydrous ethanol (ethyl acetate / anhydrous ethanol V:V=8:2), and dried at 60°C under vacuum for 12 h to obtain 3,3'-((2,2-bis((dodecyl(2-hydroxyethyl)(3-sulfonic acid propyl)ammonium methyl))propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammonium diyl))bis(propane-1-sulfonate).

[0086] Comparative Example 5

[0087] The raw material composition and preparation method of the wet flue gas desulfurization composite synergistic additive were substantially the same as those of Example 6, except that the promoter was replaced with an equal weight of a promoter prepared by the following method:

[0088] The preparation method of the promoter was substantially the same as that of Example 3, except that 3,3'-((2-((dodecyl(2-hydroxyethyl)(3-sulfonic acid propyl)ammoniumyl)methyl)propane-1,3-diyl)bis(dodecyl(2-hydroxyethyl)ammoniumyl))bis(propane-1-sulfonate) in step S4 was replaced with an equal molar amount of 3,3'-((2-((2-hydroxyethyl)(pentyl)(3-sulfonic acid propyl)ammonium methyl)propane-1,3-diyl)bis((2-hydroxyethyl)(pentyl)ammonium diyl))bis(propane-1-sulfonate);

[0089] The preparation method of 3,3'-((2-((2-hydroxyethyl)(pentyl)(3-sulfonic acid propyl)ammonium methyl)propane-1,3-diyl)bis((2-hydroxyethyl)(pentyl)ammonium diyl))bis(propane-1-sulfonate) was as follows:

[0090] N1: 150 ml of anhydrous tetrahydrofuran was stirred and mixed with 0.105 mol of 1-aminopentane under nitrogen protection, 0.1 mol of 2-chloroethanol was slowly added dropwise, and the dropping was completed in 10 min, 0.15 mol of triethylamine was added, and reacted at 50°C for 5 h. After cooling to room temperature, it was washed with saturated brine three times (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.

[0091] 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;

[0092] 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).

[0093] 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.

[0094] 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).

[0095] 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 (wherein, C t is the sulfate concentration at 1h, C0 is the initial sulfate concentration, and t is the time) to calculate the oxidation rate of CaSO3.

[0096] Flue gas desulfurization test: the desulfurization composite synergistic additive prepared in Examples 5-7 and Comparative Examples 1-5 was mixed with 100 ml of 3wt% limestone slurry (the content of the desulfurization composite synergistic additive was 1000 mg / L) uniformly, under the conditions of temperature 50℃ and rotation speed 300r / min, the initial pH of the slurry was adjusted to 5.5 by an automatic potentiometric titrator; the limestone slurry with the desulfurization composite synergistic additive was added into an absorption tower, 1wt% SO2 / N2 standard gas was introduced (the balance gas was nitrogen), the inlet SO2 concentration was measured to be 2200 ppm by using a flue gas analyzer, the outlet SO2 concentration was monitored after 1h, and the desulfurization efficiency was calculated according to the formula б= (C0-C t ) / C0 (wherein, C0 is the inlet SO2 concentration, C t is the corresponding outlet SO2 concentration at 1h).

[0097] Table 1

[0098]

[0099] As can be seen from the data in Table 1, the wet flue gas desulfurization composite synergistic additive prepared in Examples 5-7 of the present application can effectively promote the dissolution of calcium carbonate and the oxidation of calcium sulfite, and has excellent desulfurization efficiency.

[0100] The wet flue gas desulfurization composite synergistic additive prepared in the present application has good calcium carbonate dissolution rate and calcium sulfite oxidation rate, and high desulfurization efficiency, mainly because the added promoter has a multi-branched structure with catechol groups, nitroxyl radicals, quaternary ammonium salts, sulfonate groups and long-chain alkyl groups. This structure can maximize the functional site density, avoid mutual interference of single groups, and improve the contact efficiency of each unit and the reaction interface. The catechol groups in the promoter chelate Ca 2+ through the ortho-hydroxyl group, destroy the dissolution balance of CaCO3, accelerate the release of Ca 2+ , improve the calcium carbonate dissolution rate, and further improve the desulfurization efficiency. The quaternary ammonium salt in the promoter enriches HSO3 - near the catalytic site through electrostatic attraction, improves the local reactant concentration, and the nitroxyl radical activates O2 to efficiently oxidize HSO3 - to SO4 2-, avoid calcium sulfite fouling; at the same time, sulfonate enhances hydrophilicity, long-chain alkyl plays a hydrophobic role, adsorbed on the gas-liquid interface, reduce surface tension, increase the gas-liquid surface activity, thereby increasing the O2 mass transfer capacity of the gas-liquid interface, so that O2 can be more timely and effective and calcium sulfite reaction, nitrogen oxide free radicals, quaternary ammonium salt, sulfonate and long-chain alkyl synergistic effect of calcium sulfite oxidation rate, and thus improve the desulfurization efficiency. The promoter used in Comparative Example 4 has a larger reaction site density, resulting in a decrease in the efficiency of the functional site of the catechol chelate and the nitrogen oxide free radical, a decrease in the interfacial adsorption and mass transfer capacity of the surface active group, and a decrease in the overall diffusion and reaction interface contact efficiency of the molecule, thereby reducing the synergistic efficiency of each structure and resulting in a decrease in the final desulfurization efficiency.

[0101] The above is only a preferred embodiment of the present application and is not intended to limit the present application; however, for those of ordinary skill in the art, some minor changes, modifications, and equivalent variations of the above disclosed technical content can be made without departing from the scope of the technical solutions of the present application, and all such equivalent embodiments are within the scope of the present application; at the same time, any equivalent changes, modifications, and variations of the above embodiments made in accordance with the essential technology of the present application are still within the protection scope of the technical solutions of the present application.

Claims

1. A composite synergistic additive for wet flue gas desulfurization characterized in that, The raw materials include the following weight parts: organic acid 15-25 parts, organic salt 10-20 parts, inorganic salt 5-10 parts, wetting agent 4-5 parts, hygroscopic agent 5-8 parts, and accelerator 5-15 parts; The accelerator is prepared by the following method: S1: cyanuric chloride reacts with dopamine to generate intermediate 1, S2: intermediate 1 reacts with 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl 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-sulfonic acid propyl) ammonium) methyl) propane-1,3-diyl) bis(dodecyl(2-hydroxyethyl) ammonium)) bis(propane-1-sulfonate) to obtain the accelerator, and the chemical structural formula is as follows: 。 2. A composite synergistic 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. A composite synergistic 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-oxyl radical is 1:(1.05-1.1).

4. A composite synergistic 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. A composite synergistic 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-sulfonic acid propyl) ammonium) methyl) propane-1,3-diyl) bis(dodecyl(2-hydroxyethyl) ammonium)) bis(propane-1-sulfonate) is 1:(3.1-3.2).

6. A composite synergistic 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. A composite synergistic additive for wet flue gas desulfurization according to claim 1, characterized in that, The organic salt is one of sodium acetate and sodium citrate.

8. A composite synergistic additive for wet flue gas desulfurization according to claim 1, characterized in that, The inorganic salt is one of magnesium sulfate and sodium sulfate.

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

10. A process for the preparation of the composite synergistic additive for wet flue gas desulfurization according to any one of claims 1 to 9, characterized in that, The method includes the following steps: (1) The following weight parts are weighed: organic acid 15-25 parts, organic salt 10-20 parts, inorganic salt 5-10 parts, wetting agent 4-5 parts, hygroscopic agent 5-8 parts, and accelerator 5-15 parts; (2) The above materials are mixed and stirred uniformly, and are ground into powder in a planetary ball mill to obtain the wet flue gas desulfurization composite synergistic additive.

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