A flue gas desulfurization composite synergist and a preparation method thereof

Abstract

The application 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 comprises the following raw materials in parts 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 a surfactant, 2-4 parts of a pH buffer, and 5-10 parts of calcium oxide. The intermediate 1 is obtained by the ring-opening reaction of 3-(2-aminoethylamine) propyl methyl dimethoxy silane and gluconic acid lactone, and then a novel surfactant is synthesized through two-step quaternary ammonium reactions. The desulfurization composite synergist prepared by the application has good desulfurization effect and is suitable for limestone-gypsum wet flue gas desulfurization.

Description

Technical Field

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

[0002] With increasingly stringent environmental regulations, coal-fired power plants widely adopt limestone-gypsum wet desulfurization technology to control sulfur dioxide emissions. However, this technology faces numerous challenges in actual operation: First, the widespread use of high-sulfur coal leads to SO2 concentrations in flue gas far exceeding design values, rendering traditional desulfurization systems inefficient and unable to meet ultra-low emission requirements; second, the slow dissolution rate of limestone and large pH fluctuations in the slurry easily cause equipment scaling and blockage, increasing maintenance costs; furthermore, existing desulfurization synergists are mostly single-component, which, while improving local reaction efficiency, suffer from poor synergy and insufficient temperature adaptability. To address these issues, current technology urgently needs a composite synergist, combining organic acids, inorganic salts, surfactants, and buffers to improve limestone dissolution rate, SO2 absorption efficiency, and system stability.

[0003] Chinese invention patent CN104289096A discloses a high-efficiency wet desulfurization enhancer. The components and weight percentages of the enhancer are as follows: 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 enhancer provided by this invention is a composite desulfurization enhancer. It can improve the desulfurization efficiency of the desulfurization system without upgrading the system capacity. However, the desulfurization efficiency needs to be further improved. Summary of the Invention

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

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A flue gas desulfurization composite enhancer comprises the following raw materials in parts by weight:

[0007] Citric acid: 5-10 parts, dicarboxylic 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;

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

[0009] S1: Add anhydrous dimethyl sulfoxide (DMSO), 3-(2-aminoethylamine)propylmethyldimethoxysilane and gluconolactone to the reactor, stir, heat to 80-100℃, react for 8-10 h, and then process to obtain intermediate 1.

[0010] S2: Add anhydrous ethanol, intermediate 1, catalyst and bromotetradecane to the reactor, stir, reflux for 12-14 h, and then process to obtain intermediate 2.

[0011] S3: Add anhydrous acetonitrile, intermediate 2 and 1,10-dibromodecane to the reactor, stir, reflux for 12-16 h, and then perform post-treatment to obtain the surfactant.

[0012] In step S1, the mass ratio of anhydrous DMSO, 3-(2-aminoethylamine)propylmethyldimethoxysilane and gluconolactone is 80:(8-10):(8-9).

[0013] In step S2, the mass ratio of anhydrous ethanol, intermediate 1 and bromotetradecane is 100:(15-17):(12-14).

[0014] In step S2, the catalyst is triethylamine.

[0015] In step S3, the mass ratio of the anhydrous acetonitrile, intermediate 2 and 1,10-dibromodecane is 65:(8-12):(2-3).

[0016] The pH buffer is one of potassium phosphate buffer or sodium phosphate buffer.

[0017] The dicarboxylic acid is either adipic acid or oxalic acid.

[0018] The sodium salt is either sodium sulfate or sodium chloride.

[0019] The magnesium salt is one of magnesium chloride and magnesium sulfate.

[0020] A method for preparing a flue gas desulfurization composite enhancer includes the following steps:

[0021] (1) Weigh out the following by weight: citric acid: 5-10 parts, dicarboxylic 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;

[0022] (2) Add each material to the reaction vessel and stir until fully mixed. Then add the mixed material to the grinder and grind it into powder to obtain the desulfurization composite enhancer.

[0023] Due to the adoption of the above technical solutions, the beneficial effects of the present invention include:

[0024] The surfactant prepared by this invention reduces interfacial tension, enhances wettability and particle dispersibility through its amphiphilic structure, and significantly improves desulfurization efficiency, making it suitable for limestone-gypsum wet flue gas desulfurization. Detailed Implementation

[0025] The following description, in conjunction with specific embodiments, provides further details, but the present invention is not limited to these embodiments.

[0026] Example 1: Preparation of surfactants:

[0027] S1: Add 800g anhydrous DMSO, 80g 3-(2-aminoethylamine)propylmethyldimethoxysilane, and 80g gluconolactone to the reactor, stir, heat to 80℃, and react for 10h (removing the generated water using a water separator during the reaction). Then, cool to room temperature, distill under reduced pressure at 70℃ for 1h, and dry under vacuum at 80℃ for 5h to obtain intermediate 1. The reaction equation is shown below:

[0028]

[0029] Its 1H NMR data are as follows:

[0030] 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).

[0031] S2: Add 1000g anhydrous ethanol, 150g intermediate 1, 45g triethylamine and 120g bromotetradecane to the reactor, stir, reflux for 12h, and cool to room temperature; distill under reduced pressure at 60℃ for 1h, then add 400mL diethyl ether, precipitate the solid, filter, and dry under vacuum at 50℃ for 6h to obtain intermediate 2. The reaction equation is shown below:

[0032]

[0033] Its 1H NMR data are as follows:

[0034] 1 H 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).

[0035] S3: Add 650g anhydrous acetonitrile, 80g intermediate 2, and 20g 1,10-dibromodecane to the reactor, stir, reflux for 12h, cool to room temperature, distill under reduced pressure at 65℃ for 1.5h, then recrystallize with 150ml anhydrous ethanol and 300ml ethyl acetate, and dry under vacuum at 70℃ for 2h to obtain the surfactant. The reaction equation is shown below:

[0036]

[0037] Its 1H NMR data are as follows:

[0038] 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).

[0039] Example 2: Preparation of surfactants:

[0040] S1: Add 800g anhydrous DMSO, 90g 3-(2-aminoethylamine)propylmethyldimethoxysilane and 85g gluconolactone to the reactor, stir, heat to 90℃, react for 9h (use a water separator to remove the generated water during the reaction), cool to room temperature, distill under reduced pressure at 70℃ for 1h, and dry under vacuum at 80℃ for 5h to obtain intermediate 1;

[0041] S2: Add 1000g anhydrous ethanol, 160g intermediate 1, 47g triethylamine and 130g bromotetradecane to the reactor, stir, reflux for 13h, cool to room temperature; distill under reduced pressure at 60℃ for 1h, then add 400mL diethyl ether, precipitate solid, filter, and dry under vacuum at 50℃ for 6h to obtain intermediate 2.

[0042] S3: Add 650g anhydrous acetonitrile, 100g intermediate 2 and 25g 1,10-dibromodecane to the reactor, stir and reflux for 14h, cool to room temperature, distill under reduced pressure at 65℃ for 1.5h, then recrystallize with 150ml anhydrous ethanol and 300ml ethyl acetate, and dry under vacuum at 70℃ for 2h to obtain the surfactant.

[0043] Example 3: Preparation of surfactants:

[0044] S1: Add 800g anhydrous DMSO, 100g 3-(2-aminoethylamine)propylmethyldimethoxysilane and 90g gluconolactone to the reactor, stir, heat to 100℃, react for 8h (use a water separator to remove the generated water during the reaction), cool to room temperature, distill under reduced pressure at 70℃ for 1h, and dry under vacuum at 80℃ for 5h to obtain intermediate 1;

[0045] S2: Add 1000g anhydrous ethanol, 170g intermediate 1, 48g triethylamine and 140g bromotetradecane to the reactor, stir, reflux for 14h, cool to room temperature; distill under reduced pressure at 60℃ for 1h, then add 400mL diethyl ether, precipitate solid, filter, and dry under vacuum at 50℃ for 6h to obtain intermediate 2.

[0046] S3: Add 650g anhydrous acetonitrile, 120g intermediate 2 and 30g 1,10-dibromodecane to the reactor, stir and reflux for 16h, cool to room temperature, distill under reduced pressure at 65℃ for 1.5h, then recrystallize with 150ml anhydrous ethanol and 300ml ethyl acetate, and dry under vacuum at 70℃ for 2h to obtain the surfactant.

[0047] Example 4: Preparation of desulfurization composite synergist:

[0048] (1) Weigh: citric acid: 50g, dicarboxylic acid (adipic acid): 200g, sodium formate: 150g, sodium sulfate: 150g, magnesium chloride: 120g, surfactant (prepared in Example 1): 20g, pH buffer (potassium phosphate buffer): 20g, calcium oxide: 50g;

[0049] (2) Add each material to the reactor and stir at room temperature at a speed of 1500 r / min; stir for 45 min to mix thoroughly and evenly. Add the mixed material to the grinder and grind it into powder to obtain the desulfurization composite enhancer.

[0050] Example 5: Preparation of desulfurization composite synergist:

[0051] (1) Weigh: citric acid: 80g, dicarboxylic acid (adipic acid): 250g, sodium formate: 175g, sodium sulfate: 180g, magnesium chloride: 160g, surfactant (prepared in Example 2): 30g, pH buffer (potassium phosphate buffer): 30g, calcium oxide: 75g;

[0052] (2) Add each material to the reactor and stir at room temperature at a speed of 1500 r / min; stir for 45 min to mix thoroughly and evenly. Add the mixed material to the grinder and grind it into powder to obtain the desulfurization composite enhancer.

[0053] Example 6: Preparation of desulfurization composite synergist:

[0054] (1) Weigh: citric acid: 100g, dicarboxylic acid (oxalic acid): 300g, sodium formate: 200g, sodium chloride: 200g, magnesium sulfate: 180g, surfactant (prepared in Example 3): 40g, pH buffer (sodium phosphate buffer): 40g, calcium oxide: 100g;

[0055] (2) Add each material to the reactor and stir at room temperature at a speed of 1500 r / min; stir for 45 min to mix thoroughly and evenly. Add the mixed material to the grinder and grind it into powder to obtain the desulfurization composite enhancer.

[0056] Comparative Example 1

[0057] The raw material composition and preparation method of the flue gas desulfurization composite enhancer are basically the same as those in Example 5, except that no surfactant is added to the components.

[0058] Comparative Example 2

[0059] The raw material composition and preparation method of the flue gas desulfurization composite enhancer are basically the same as those in Example 5. The difference is that the surfactant is replaced with an equal weight of the intermediate 2 prepared in step S2 of Example 2.

[0060] Comparative Example 3

[0061] The raw material composition and preparation method of the flue gas desulfurization composite enhancer are basically the same as those in Example 5, except that the surfactant is replaced with an equal weight of surfactant prepared by the following method:

[0062] The preparation method of the surfactant is basically the same as that in Example 2, except that 3-(2-aminoethylamine)propylmethyldimethoxysilane in step S1 is replaced with an equal weight of N-aminoethyl-3-aminopropyltriethoxysilane.

[0063] Comparative Example 4

[0064] The raw material composition and preparation method of the flue gas desulfurization composite enhancer are basically the same as those in Example 5, except that the surfactant is replaced with an equal weight of surfactant prepared by the following method:

[0065] The preparation method of the surfactant is basically the same as that in Example 2, except that gluconolactone in step S1 is replaced with an equal weight of caprolactone.

[0066] Comparative Example 5

[0067] The raw material composition and preparation method of the flue gas desulfurization composite enhancer are basically the same as those in Example 5, except that the surfactant is replaced with an equal weight of surfactant prepared by the following method:

[0068] The preparation method of the surfactant is basically the same as that in Example 2, except that the tetradecane in step S2 is replaced with an equal weight of hexane.

[0069] Comparative Example 6

[0070] The raw material composition and preparation method of the flue gas desulfurization composite enhancer are basically the same as those in Example 5, except that the surfactant is replaced with an equal weight of surfactant prepared by the following method:

[0071] The preparation method of the surfactant is basically the same as that in Example 2, except that the tetradecane in step S2 is replaced with an equal weight of octadecane.

[0072] Comparative Example 7

[0073] The raw material composition and preparation method of the flue gas desulfurization composite enhancer are basically the same as those in Example 5, except that the surfactant is replaced with an equal weight of surfactant prepared by the following method:

[0074] The preparation method of the surfactant is basically the same as that in Example 2, except that 1,10-dibromodecane in step S3 is replaced with an equal weight of 1,4-dibromobutane.

[0075] Comparative Example 8

[0076] The raw material composition and preparation method of the flue gas desulfurization composite enhancer are basically the same as those in Example 5. The difference is that the surfactant is replaced with an equal weight of amino-modified organosilicon (model: Shin-Etsu KF-889).

[0077] 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 to dissolve, and then bring the volume to 1L with deionized water to obtain the 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 to dissolve, and then bring the volume to 1L with deionized water to obtain the sodium phosphate buffer.

[0078] The usage and testing methods for desulfurization enhancers are as follows:

[0079] (1) Prepare limestone slurry by mixing limestone (calcium carbonate content 97.8 wt%) with water at a weight ratio of 15:100;

[0080] (2) Add the desulfurization enhancer prepared in this application or comparative example to the above limestone slurry, wherein the desulfurization enhancer accounts for 2wt% of the total mass, the temperature is controlled at 50℃, the rotation speed is 500r / min, and the mixture is stirred for 4h;

[0081] (3) Limestone slurry with added desulfurization enhancer was added to the absorption tower for desulfurization performance testing. The SO2 concentration in the inlet flue gas was 2000 mg / Nm³. 3(The equilibrium gas is nitrogen), the liquid-to-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.

[0082] Table 1 Data Test Table

[0083]

[0084] As can be seen from Table 1, the desulfurization composite synergist prepared in Examples 4-6 of this invention can effectively improve the desulfurization effect in the treatment process, with a desulfurization efficiency of over 99%.

[0085] The surfactant prepared in this application comprises a hydrophobic portion composed of long-chain alkyl groups, a polyhydroxy structure formed by the ring-opening of gluconolactone, and a hydrophilic portion of quaternized amine groups. The long-chain alkyl groups in the molecule enhance the directional adsorption capacity at the liquid-gas or liquid-solid interface, effectively reducing the surface tension of the slurry and promoting 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 imparts positive charge to the molecule, making it easy to adsorb onto the surface of negatively charged sulfide particles or bubbles, enriching reactants through micellization, increasing local concentration, and accelerating the dissolution and oxidation reaction kinetics of SO2. The siloxane alkyl groups can enhance the anchoring ability of the molecule on the particle surface, forming a stable interfacial layer and maintaining the durability of the desulfurization reaction interface. In summary, this surfactant, through the synergistic optimization of multiple structures, significantly improves the SO2 absorption efficiency and oxidation rate, enabling it to achieve a desulfurization efficiency of over 99% when applied to limestone-gypsum wet flue gas desulfurization.

[0086] 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 flue gas desulfurization composite synergist, characterized in that, The ingredients include the following parts by weight: Citric acid: 5-10 parts, dicarboxylic 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-aminoethylamine)propylmethyldimethoxysilane and gluconolactone to the reactor, stir, heat to 80-100℃, react for 8-10 h, and then process to obtain intermediate 1. S2: Add anhydrous ethanol, intermediate 1, catalyst and bromotetradecane to the reactor, stir, reflux for 12-14 h, and then process to obtain intermediate 2. S3: Add anhydrous acetonitrile, intermediate 2 and 1,10-dibromodecane to the reactor, stir, reflux for 12-16 h, and then perform post-treatment to obtain the surfactant.

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

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

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

5. The 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. The flue gas desulfurization composite synergist according to claim 1, characterized in that, The pH buffer is one of potassium phosphate buffer or sodium phosphate buffer.

7. The flue gas desulfurization composite synergist according to claim 1, characterized in that, The dicarboxylic acid is either adipic acid or oxalic acid.

8. The flue gas desulfurization composite synergist according to claim 1, characterized in that, The sodium salt is either sodium sulfate or 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 1-9, characterized in that, Includes the following steps: (1) Weigh out the following by weight: citric acid: 5-10 parts, dicarboxylic 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; (2) Add each material to the reaction vessel and stir until fully mixed. Then add the mixed material to the grinder and grind it into powder to obtain the desulfurization composite enhancer.

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