Flue gas desulfurization composite synergist and preparation method thereof

Abstract

The invention discloses a flue gas desulfurization composite synergist and a preparation method thereof, and relates to the technical field of flue gas desulfurization. The desulfurization composite synergist is prepared from the following raw materials in parts by weight: 5 to 10 parts of citric acid, 20 to 30 parts of binary acid, 15 to 20 parts of sodium formate, 15 to 20 parts of sodium salt, 12 to 18 parts of magnesium salt, 2 to 4 parts of surfactant, 2 to 4 parts of pH buffering agent and 5 to 10 parts of calcium oxide. The preparation method comprises the following steps: carrying out a ring-opening reaction on 3-(2-aminoethylamine) propyl methyl dimethoxy silane and glucolactone to obtain an intermediate 1, and then carrying out a two-step quaternization reaction to synthesize the novel surfactant. The prepared desulfurization composite synergist has a good desulfurization effect and is suitable for limestone-gypsum wet flue gas desulfurization.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas desulfurization, and in particular to a flue gas desulfurization composite synergist and a preparation method thereof. Background Art

[0002] With increasingly stringent environmental regulations, coal-fired power plants generally use limestone-gypsum wet desulfurization technology to control sulfur dioxide emissions. However, this technology faces many challenges in actual operation: First, the widespread use of high-sulfur coal causes the SO2 concentration in the flue gas to far exceed the design value, and the efficiency of traditional desulfurization systems is insufficient, making it difficult to meet ultra-low emission requirements; second, the slow dissolution rate of limestone and large fluctuations in the slurry pH can easily cause equipment scaling and blockage, increasing maintenance costs; in addition, existing desulfurization enhancers are mostly single-component, and although they can improve local reaction efficiency, they have problems such as poor synergy and insufficient temperature adaptability. To address these problems, current technology urgently needs a composite enhancer that improves the limestone dissolution rate, SO2 absorption efficiency, and system stability by combining components such as organic acids, inorganic salts, surfactants, and buffers.

[0003] Chinese invention patent publication number CN104289096A discloses a high-efficiency wet flue gas desulfurization synergist. The components of the desulfurization synergist and the weight percentage of each component are: citric acid: 20-70%; DBA: 10-40%; nano-calcium sulfate: 1-5%; magnesium sulfate: 2-7%; nano-manganese sulfate: 1-5%; the wet flue gas desulfurization synergist provided by the invention is a composite desulfurization synergist that can improve the desulfurization efficiency of the desulfurization system without increasing the capacity of the desulfurization system. However, the desulfurization efficiency needs to be further improved. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a flue gas desulfurization composite synergist and a preparation method thereof.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions: A flue gas desulfurization composite synergist comprises the following raw materials in parts by weight: Citric acid: 5-10 parts, dibasic acid: 20-30 parts, sodium formate: 15-20 parts, sodium salt: 15-20 parts, magnesium salt: 12-18 parts, surfactant: 2-4 parts, pH buffer 2-4 parts, calcium oxide: 5-10 parts; The surfactant is prepared by the following method: S1: Add anhydrous dimethyl sulfoxide (DMSO), 3-(2-aminoethylamino)propylmethyldimethoxysilane and gluconolactone to the reactor, stir, heat to 80-100°C, react for 8-10 hours, and post-treat to obtain intermediate 1; S2: adding anhydrous ethanol, intermediate 1, catalyst and tetradecane bromide to the reactor, stirring, reflux reaction for 12-14 hours, and post-processing to obtain intermediate 2; S3: Add anhydrous acetonitrile, intermediate 2 and 1,10-dibromodecane to the reactor, stir, reflux and react for 12-16 hours, and then post-treat to obtain the surfactant.

[0006] In step S1, the mass ratio of anhydrous DMSO, 3-(2-aminoethylamino)propylmethyldimethoxysilane and gluconolactone is 80:(8-10):(8-9).

[0007] In step S2, the mass ratio of the anhydrous ethanol, the intermediate 1 and the brominated tetradecane is 100:(15-17):(12-14).

[0008] In step S2, the catalyst is triethylamine.

[0009] In step S3, the mass ratio of the anhydrous acetonitrile, intermediate 2 and 1,10-dibromodecane is 65:(8-12):(2-3).

[0010] The pH buffer is one of potassium phosphate buffer and sodium phosphate buffer.

[0011] The dibasic acid is one of adipic acid and oxalic acid.

[0012] The sodium salt is one of sodium sulfate and sodium chloride.

[0013] The magnesium salt is one of magnesium chloride and magnesium sulfate.

[0014] A method for preparing a flue gas desulfurization composite synergist comprises the following steps: (1) Weigh by weight: 5-10 parts of citric acid, 20-30 parts of dibasic acid, 15-20 parts of sodium formate, 15-20 parts of sodium salt, 12-18 parts of magnesium salt, 2-4 parts of surfactant, 2-4 parts of pH buffer, and 5-10 parts of calcium oxide; (2) Add all materials into the reactor and stir to mix them thoroughly. Add the mixed materials into the grinder and grind them into powder to obtain the desulfurization composite synergist.

[0015] Due to the adoption of the above technical solution, the beneficial effects of the present invention include: The surfactant prepared by the present invention reduces interfacial tension and enhances wettability and particle dispersibility through an amphiphilic structure, thereby significantly improving desulfurization efficiency and being suitable for limestone-gypsum wet flue gas desulfurization. DETAILED DESCRIPTION

[0016] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0017] Example 1 Preparation of surfactant: S1: 800 g of anhydrous DMSO, 80 g of 3-(2-aminoethylamino)propylmethyldimethoxysilane, and 80 g of gluconolactone were added to a reactor, stirred, and heated to 80°C. The reaction was continued for 10 h (a water separator was used to remove the generated water during the reaction). The reaction temperature was then cooled to room temperature, and the mixture was distilled under reduced pressure at 70°C for 1 h. The mixture was then dried under vacuum at 80°C for 5 h to obtain intermediate 1. The reaction equation is shown below:

[0018] Its H-NMR spectrum data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 7.36 (d, J = 9.5 Hz, 1H), 5.39 (d, J= 5.1 Hz, 1H), 5.08 (d, J = 5.6 Hz, 1H), 4.48 (d, J = 5.2 Hz, 1H), 4.37 (d, J= 5.3 Hz, 1H), 4.25 – 4.16 (m, 2H), 4.09 (m, 1H), 3.88 – 3.68 (m, 3H), 3.52(ddd, J = 11.5, 5.6, 4.9 Hz, 1H), 3.46 (s, 6H), 3.35 – 3.19 (m, 2H), 2.88 –2.80 (m, 2H), 2.64 (td, J = 6.4, 4.2 Hz, 2H), 1.92 (tt, J = 5.1, 4.2 Hz, 1H), 1.55 – 1.43 (m, 2H), 0.77 (t, J = 8.9 Hz, 2H), 0.14 (s, 3H).

[0019] S2: 1000 g of anhydrous ethanol, 150 g of intermediate 1, 45 g of triethylamine, and 120 g of tetradecane bromide were added to the reactor, stirred, and refluxed for 12 h. The mixture was cooled to room temperature. The mixture was distilled under reduced pressure at 60°C for 1 h. Then, 400 mL of ether was added to precipitate a solid, which was filtered and dried under vacuum at 50°C for 6 h to obtain intermediate 2. The reaction equation is shown below:

[0020] Its H-NMR spectrum data are as follows: 1H NMR (400 MHz, Chloroform- d ) δ 7.30 (t, J = 4.2 Hz, 1H), 5.39 (d, J= 5.1 Hz, 1H), 5.08 (d, J = 5.6 Hz, 1H), 4.48 (d, J = 5.2 Hz, 1H), 4.37 (d, J= 5.3 Hz, 1H), 4.24 – 4.16 (m, 2H), 4.09 (m, 1H), 3.87 – 3.65 (m, 3H), 3.63 –3.18 (m, 9H), 2.77 – 2.62 (m, 2H), 2.56 – 2.40 (m, 4H), 1.59 – 1.39 (m, 4H),1.34 – 1.13 (m, 22H), 0.95 – 0.85 (m, 3H), 0.78 (t, J = 9.5 Hz, 2H), 0.14 (s, 3H).

[0021] S3: Add 650g of anhydrous acetonitrile, 80g of intermediate 2, and 20g of 1,10-dibromodecane to the reactor, stir, and reflux for 12h. Cool to room temperature, distill under reduced pressure at 65°C for 1.5h, then recrystallize with 150ml of anhydrous ethanol and 300ml of ethyl acetate, and dry under vacuum at 70°C for 2h to obtain the surfactant. The reaction equation is as follows:

[0022] Its H-NMR spectrum data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 8.53 (t, J = 3.5 Hz, 2H), 5.40 (d, J= 5.1 Hz, 2H), 5.08 (d, J = 5.6 Hz, 2H), 4.48 (d, J = 5.2 Hz, 4H), 4.37 (d, J= 5.3 Hz, 6H), 3.71 (d, J = 4.0 Hz, 10H), 3.60 – 3.29 (m, 30H), 1.93 – 1.56 (m, 12H), 1.46 – 1.18 (m, 56H), 1.01 (td, J = 10.4, 0.4 Hz, 4H), 0.91 – 0.82(m, 6H), 0.14(s, 6H).

[0023] Example 2 Preparation of surfactant: S1: 800 g of anhydrous DMSO, 90 g of 3-(2-aminoethylamino)propylmethyldimethoxysilane, and 85 g of gluconolactone were added to a reactor, stirred, and heated to 90°C. The reaction was carried out for 9 h (a water separator was used to remove the generated water during the reaction). The reaction temperature was then cooled to room temperature, and the mixture was distilled under reduced pressure at 70°C for 1 h. The mixture was then dried under vacuum at 80°C for 5 h to obtain intermediate 1. S2: 1000 g of anhydrous ethanol, 160 g of intermediate 1, 47 g of triethylamine, and 130 g of tetradecane bromide were added to the reactor, stirred, and refluxed for 13 h. The mixture was cooled to room temperature and distilled under reduced pressure at 60°C for 1 h. 400 mL of ether was then added to precipitate a solid, which was filtered and dried under vacuum at 50°C for 6 h to obtain intermediate 2. S3: Add 650 g of anhydrous acetonitrile, 100 g of intermediate 2 and 25 g of 1,10-dibromodecane to the reactor, stir, reflux for 14 h, cool to room temperature, and distill under reduced pressure at 65°C for 1.5 h. Then, recrystallize with 150 ml of anhydrous ethanol and 300 ml of ethyl acetate, and dry under vacuum at 70°C for 2 h to obtain the surfactant.

[0024] Example 3 Preparation of surfactant: S1: 800 g of anhydrous DMSO, 100 g of 3-(2-aminoethylamino)propylmethyldimethoxysilane, and 90 g of gluconolactone were added to a reactor, stirred, and heated to 100°C. The reaction was carried out for 8 h (a water separator was used to remove the generated water during the reaction). The reaction mixture was cooled to room temperature, and the mixture was distilled under reduced pressure at 70°C for 1 h. The mixture was then dried under vacuum at 80°C for 5 h to obtain intermediate 1. S2: 1000 g of anhydrous ethanol, 170 g of intermediate 1, 48 g of triethylamine, and 140 g of tetradecane bromide were added to the reactor, stirred, and refluxed for 14 h. The mixture was cooled to room temperature and distilled under reduced pressure at 60°C for 1 h. 400 mL of ether was then added to precipitate a solid, which was filtered and dried under vacuum at 50°C for 6 h to obtain intermediate 2. S3: Add 650 g of anhydrous acetonitrile, 120 g of intermediate 2 and 30 g of 1,10-dibromodecane to the reactor, stir, reflux for 16 h, cool to room temperature, and distill under reduced pressure at 65°C for 1.5 h. Then, recrystallize with 150 ml of anhydrous ethanol and 300 ml of ethyl acetate, and dry under vacuum at 70°C for 2 h to obtain the surfactant.

[0025] Example 4 Preparation of desulfurization composite synergist: (1) Weigh: 50 g citric acid, 200 g dibasic acid (adipic acid), 150 g sodium formate, 150 g sodium sulfate, 120 g magnesium chloride, 20 g surfactant (prepared in Example 1), 20 g pH buffer (potassium phosphate buffer), and 50 g calcium oxide. (2) Add all materials into the reactor and stir at room temperature at a speed of 1500r / min; stir for 45 minutes to mix thoroughly, add the mixed materials into the grinder, grind into powder to obtain the desulfurization composite synergist.

[0026] Example 5 Preparation of desulfurization composite synergist: (1) Weigh: 80 g of citric acid, 250 g of dibasic acid (adipic acid), 175 g of sodium formate, 180 g of sodium sulfate, 160 g of magnesium chloride, 30 g of surfactant (prepared in Example 2), 30 g of pH buffer (potassium phosphate buffer), and 75 g of calcium oxide; (2) Add all materials into the reactor and stir at room temperature at a speed of 1500r / min; stir for 45 minutes to mix thoroughly, add the mixed materials into the grinder, grind into powder to obtain the desulfurization composite synergist.

[0027] Example 6 Preparation of desulfurization composite synergist: (1) Weigh: 100 g citric acid, 300 g dibasic acid (oxalic acid), 200 g sodium formate, 200 g sodium chloride, 180 g magnesium sulfate, 40 g surfactant (prepared in Example 3), 40 g pH buffer (sodium phosphate buffer), and 100 g calcium oxide. (2) Add all materials into the reactor and stir at room temperature at a speed of 1500r / min; stir for 45 minutes to mix thoroughly, add the mixed materials into the grinder, grind into powder to obtain the desulfurization composite synergist.

[0028] Comparative Example 1 The raw material composition and preparation method of the flue gas desulfurization composite synergist are basically the same as those in Example 5, except that no surfactant is added to the composition.

[0029] Comparative Example 2 The raw material composition and preparation method of the flue gas desulfurization composite synergist are basically the same as those in Example 5, except that the surfactant is replaced by an equal weight of the intermediate 2 prepared in step S2 of Example 2.

[0030] Comparative Example 3 The raw material composition and preparation method of the flue gas desulfurization composite synergist are basically the same as those in Example 5, except that the surfactant is replaced by an equal weight of a surfactant prepared by the following method: The preparation method of the surfactant is basically the same as that of Example 2, except that the 3-(2-aminoethylamino)propylmethyldimethoxysilane in step S1 is replaced by an equal weight of N-aminoethyl-3-aminopropyltriethoxysilane.

[0031] Comparative Example 4 The raw material composition and preparation method of the flue gas desulfurization composite synergist are basically the same as those in Example 5, except that the surfactant is replaced by an equal weight of a surfactant prepared by the following method: The preparation method of the surfactant is basically the same as that of Example 2, except that the gluconolactone in step S1 is replaced by an equal weight of caprolactone.

[0032] Comparative Example 5 The raw material composition and preparation method of the flue gas desulfurization composite synergist are basically the same as those in Example 5, except that the surfactant is replaced by an equal weight of a surfactant prepared by the following method: The preparation method of the surfactant is basically the same as that of Example 2, except that the tetradecane bromide in step S2 is replaced by an equal weight of hexyl bromide.

[0033] Comparative Example 6 The raw material composition and preparation method of the flue gas desulfurization composite synergist are basically the same as those in Example 5, except that the surfactant is replaced by an equal weight of a surfactant prepared by the following method: The preparation method of the surfactant is basically the same as that of Example 2, except that the brominated tetradecane in step S2 is replaced by an equal weight of brominated octadecane.

[0034] Comparative Example 7 The raw material composition and preparation method of the flue gas desulfurization composite synergist are basically the same as those in Example 5, except that the surfactant is replaced by an equal weight of a surfactant prepared by the following method: The preparation method of the surfactant is basically the same as that of Example 2, except that the 1,10-dibromodecane in step S3 is replaced by an equal weight of 1,4-dibromobutane.

[0035] Comparative Example 8 The raw material composition and preparation method of the flue gas desulfurization composite synergist are basically the same as those in Example 5, except that the surfactant is replaced by an equal weight of amino-modified silicone (model: Shin-Etsu KF-889).

[0036] The potassium phosphate buffer used in this application is prepared by the following method: weigh 7.63g of dipotassium hydrogen phosphate and 9.83g of potassium dihydrogen phosphate, add them to 800ml of deionized water, stir and dissolve, and dilute to 1L with deionized water to obtain potassium phosphate buffer; the sodium phosphate buffer is prepared by the following method: weigh 7.48g of disodium hydrogen phosphate and 8.81g of sodium dihydrogen phosphate, add them to 800ml of deionized water, stir and dissolve, and dilute to 1L with deionized water to obtain sodium phosphate buffer.

[0037] The usage and testing methods of desulfurization synergist are as follows: (1) limestone (calcium carbonate content 97.8wt%) and water in a weight ratio of 15:100 to prepare limestone slurry; (2) Add the desulfurization synergist prepared in the present application or the comparative example to the above-mentioned limestone slurry, wherein the desulfurization synergist accounts for 2wt% of the total mass, control the temperature to 50°C, the rotation speed to 500r / min, and stir for 4h; (3) The limestone slurry with added desulfurization synergist was added into the absorption tower to test the desulfurization performance. The SO2 concentration of the inlet flue gas was 2000 mg / Nm 3 (The balance gas is nitrogen), the liquid-gas ratio is 10.5, the SO2 concentration in the outlet flue gas is monitored, and then the desulfurization efficiency is calculated. Desulfurization efficiency = (inlet SO2 concentration - outlet SO2 concentration) / inlet SO2 concentration. The results are shown in Table 1.

[0038] Table 1 Data test table

[0039] It can be seen from Table 1 that the desulfurization composite synergist prepared in Examples 4-6 of the present invention can effectively improve the desulfurization effect during the treatment process, and the desulfurization efficiency reaches more than 99%.

[0040] The surfactant prepared by the present application includes the hydrophobic part that long-chain alkyl is constituted and the polyhydroxy structure formed after the gluconolactone ring opening and the hydrophilic part of quaternized amine group. The long-chain alkyl in the molecule enhances the directional adsorption ability at the liquid-gas or liquid-solid interface, effectively reduces the slurry surface tension, and promotes the dispersion and mass transfer of SO2 gas in the slurry; The polyhydroxy structure derived from gluconolactone has strong hydrophilicity, which can improve the wetting effect of the desulfurization synergist; The quaternary ammonium salt group gives the molecule positive charge, is easy to be adsorbed on the surface of negatively charged sulfide particles or bubbles, enriches reactants by micellization, improves local concentration, and accelerates SO2 dissolution and oxidation reaction kinetics; Siloxane group can enhance the anchoring ability of molecules on the particle surface, forms a stable interface layer, and maintains the persistence of the desulfurization reaction interface. In summary, the surfactant optimizes the interface environment in the desulfurization process through multiple structures, significantly improves SO2 absorption efficiency and oxidation rate, so that the desulfurization efficiency reaches more than 99% when it is applied to limestone-gypsum wet flue gas desulfurization.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. However, any equivalent changes, modifications and evolutions made by ordinary technicians in this field without departing from the scope of the technical solution of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A flue gas desulfurization composite synergist, characterized in that: The composition comprises the following raw materials in parts by weight: Citric acid: 5-10 parts, dibasic acid: 20-30 parts, sodium formate: 15-20 parts, sodium salt: 15-20 parts, magnesium salt: 12-18 parts, surfactant: 2-4 parts, pH buffer 2-4 parts, calcium oxide: 5-10 parts; The surfactant is prepared by the following method: S1: Add anhydrous DMSO, 3-(2-aminoethylamino)propylmethyldimethoxysilane and gluconolactone to a reactor, stir, heat to 80-100°C, react for 8-10 hours, and post-treat to obtain intermediate 1; S2: adding anhydrous ethanol, intermediate 1, catalyst and tetradecane bromide to the reactor, stirring, reflux reaction for 12-14 hours, and post-processing to obtain intermediate 2; S3: Add anhydrous acetonitrile, intermediate 2 and 1,10-dibromodecane to the reactor, stir, reflux and react for 12-16 hours, and then post-treat to obtain the surfactant.

2. A flue gas desulfurization composite synergist according to claim 1, characterized in that: In step S1, the mass ratio of anhydrous DMSO, 3-(2-aminoethylamino)propylmethyldimethoxysilane and gluconolactone is 80:(8-10):(8-9).

3. A flue gas desulfurization composite synergist according to claim 1, characterized in that: In step S2, the mass ratio of the anhydrous ethanol, the intermediate 1 and the brominated tetradecane is 100:(15-17):(12-14).

4. A flue gas desulfurization composite synergist according to claim 1, characterized in that: In step S2, the catalyst is triethylamine.

5. A flue gas desulfurization composite synergist according to claim 1, characterized in that: In step S3, the mass ratio of the anhydrous acetonitrile, intermediate 2 and 1,10-dibromodecane is 65:(8-12):(2-3).

6. A flue gas desulfurization composite synergist according to claim 1, characterized in that: The pH buffer is one of potassium phosphate buffer and sodium phosphate buffer.

7. The flue gas desulfurization composite synergist according to claim 1, characterized in that: The dibasic acid is one of adipic acid and oxalic acid.

8. The flue gas desulfurization composite synergist according to claim 1, characterized in that: The sodium salt is one of sodium sulfate and sodium chloride.

9. The flue gas desulfurization composite synergist according to claim 1, characterized in that: The magnesium salt is one of magnesium chloride and magnesium sulfate.

10. A method for preparing the flue gas desulfurization composite synergist according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Weigh by weight: 5-10 parts of citric acid, 20-30 parts of dibasic acid, 15-20 parts of sodium formate, 15-20 parts of sodium salt, 12-18 parts of magnesium salt, 2-4 parts of surfactant, 2-4 parts of pH buffer, and 5-10 parts of calcium oxide; (2) Add all materials into the reactor and stir to mix them thoroughly. Add the mixed materials into the grinder and grind them into powder to obtain the desulfurization composite synergist.

Images