High-efficiency wet flue gas desulfurization agent and preparation method thereof

Abstract

The application discloses a high-efficiency wet flue gas desulfurization agent and a preparation method thereof, and relates to the technical field of flue gas desulfurization. The high-efficiency wet flue gas desulfurization agent comprises the following raw materials in parts by weight: 5-15 parts of organic acid, 10-25 parts of alkaline activator, 3-10 parts of dispersant and 0.5-3 parts of catalytic oxidant. The high-efficiency wet flue gas desulfurization agent prepared by the application has good limestone dissolution rate and excellent desulfurization efficiency.

Description

Technical Field

[0001] This invention relates to the field of flue gas desulfurization technology, specifically to a high-efficiency wet flue gas desulfurization agent and its preparation method. Background Technology

[0002] Coal-fired power generation, a pillar of my country's electricity supply, produces large amounts of flue gas containing sulfur dioxide, a major pollutant contributing to acid rain, photochemical smog, and harming human health and the environment. Therefore, efficient desulfurization of power plant flue gas is crucial for air pollution control. Currently, limestone-gypsum wet desulfurization is the most widely used process in power plant flue gas treatment, its core reaction relying on the efficient absorption of sulfur dioxide from flue gas by limestone slurry. However, in actual operation, limestone slurry generally suffers from poor solubility and dispersibility, severely impacting the overall system performance. Due to the tendency of solid particles to agglomerate and settle, the slurry system exhibits poor stability and low uniformity, easily causing blockages in the conveying pipelines and spray nozzles, increasing system operating resistance and energy consumption. It also significantly reduces the effective contact area between the slurry and flue gas, leading to a decrease in gas-liquid mass transfer efficiency. These problems hinder the full desulfurization reaction, ultimately resulting in reduced desulfurization efficiency, low limestone utilization, and increased desulfurization operating costs for power plants and steel mills. Therefore, it is particularly important to develop a desulfurizing agent that can improve the dispersibility of limestone slurry. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this invention is to provide a highly efficient wet flue gas desulfurization agent and its preparation method.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A high-efficiency wet flue gas desulfurization agent, comprising the following raw materials in parts by weight: Organic acid: 5-15 parts, alkaline activator: 10-25 parts, dispersant: 3-10 parts, catalytic oxidant: 0.5-3 parts; The dispersant is prepared by the following method: S1: Pentaerythritol reacts with 3,6-dimethyl-1,4-dioxane-2,5-dione in the presence of a catalyst to form a four-armed compound. S2: 1-Chlorododecane reacts with 3-[2-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]ethoxy]propionic acid to form a long-chain compound. S3: Long-chain compounds react with sodium 5-bromo-1-pentanesulfonate to form zwitterionic compounds. S4: A zwitterionic compound reacts with a tetrapod compound to obtain a dispersant.

[0005] In step S1, the molar ratio of pentaerythritol to 3,6-dimethyl-1,4-dioxane-2,5-dione is 1:(8-16).

[0006] In step S2, the molar ratio of 1-chlorododecane to 3-[2-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]ethoxy]propionic acid is (2.05-2.1):1.

[0007] In step S3, the molar ratio of the long-chain compound to sodium 5-bromo-1-pentanesulfonate is 1:(1.05-1.2).

[0008] In step S4, the molar ratio of the zwitterionic compound to the tetra-armed compound is (4.1-4.2):1.

[0009] In step S1, the catalyst is stannous octoate.

[0010] The organic acid is one of citric acid, succinic acid, and adipic acid.

[0011] The alkaline activator is either sodium hydroxide or potassium hydroxide.

[0012] The catalytic oxidant is one of manganese sulfate or sodium iron ethylenediaminetetraacetate.

[0013] A method for preparing a high-efficiency wet flue gas desulfurization agent includes the following steps: (1) Weigh out the following by weight: organic acid: 5-15 parts, alkaline activator: 10-25 parts, dispersant: 3-10 parts, catalytic oxidant: 0.5-3 parts; (2) Mix the above materials, stir evenly, and grind them into powder in a planetary ball mill to obtain flue gas desulfurizer.

[0014] Due to the adoption of the above technical solutions, the beneficial effects of the present invention include: The high-efficiency wet flue gas desulfurization agent prepared by this invention has good limestone solubility and excellent desulfurization efficiency. The added dispersant has a four-arm structure, which gives the dispersant high steric hindrance and interfacial adsorption capacity, enabling it to effectively anchor on the surface of limestone particles, inhibit limestone particle agglomeration, improve dispersibility, thereby promoting the wetting and dissolution of limestone in the slurry, and improving limestone utilization and desulfurization efficiency. Detailed Implementation

[0015] The following description, in conjunction with specific embodiments, provides further details, but the present invention is not limited to these embodiments.

[0016] Example 1: Preparation of dispersant: S1: Under nitrogen protection, 800 ml of DMF (N,N-dimethylformamide), 0.1 mol of pentaerythritol, and 0.8 mol of 3,6-dimethyl-1,4-dioxane-2,5-dione were added to the reactor. The mixture was stirred and mixed, heated to 130 °C, and stirred for 15 min. Then, 1 g of stannous octoate catalyst was added. After reacting for 20 h, the mixture was cooled to room temperature and distilled under reduced pressure at 80 °C for 2 h to obtain the crude product. The crude product was added to 500 ml of chloroform and stirred until mixed. Then, 600 ml of cold methanol was added, and the mixture was allowed to stand to precipitate. The precipitate was filtered and washed three times with methanol (300 ml each time). The mixture was then dried under vacuum at 60 °C for 10 h to obtain the four-arm compound with a number average molecular weight of 1289. The reaction equation is shown below:

[0017] Its 1H NMR data are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 5.44 – 5.31 (m,12H), 4.24 (qd, J = 6.9, 5.6 Hz, 4H), 4.12 (s, 8H), 3.17 (d, J = 5.6 Hz, 4H), 1.40 – 1.30 (m, 48H).

[0018] S2: Add 300 ml of anhydrous ethanol and 0.205 mol of 1-chlorododecane to the reactor, heat to 35 °C and stir for 20 min, add 0.21 mol of triethylamine, and then add 0.1 mol of 3-[2-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]ethoxy]propionic acid in 5 batches, with a 5 min interval between batches. Stir and mix well, heat to 60 °C and react for 8 h, filter, distill under reduced pressure at 50 °C for 2 h, then pour into 500 ml of acetone, stir to precipitate, filter, wash three times with acetone (150 ml of acetone each time), and dry under vacuum at 45 °C for 12 h to obtain the long-chain compound; the reaction equation is shown below:

[0019] Its 1H NMR data are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 10.60 (s, 1H),3.83 – 3.44 (m, 16H), 2.63 (t, J = 6.0 Hz, 2H), 2.51 (q, J = 6.2 Hz, 6H),1.52 – 1.20 (m, 40H), 0.94 – 0.84 (m, 6H).

[0020] S3: Add 350 mL of DMF and 0.105 mol of sodium 5-bromo-1-pentanesulfonate to the reactor, stir and mix well, then add 0.1 mol of the long-chain compound in 5 batches (5 min apart), heat to 70 °C, react for 10 h, cool to room temperature, slowly add to 500 mL of acetone, stir, precipitate, filter, wash three times with acetone (200 mL each time), and dry under vacuum at 45 °C for 12 h to obtain the zwitterionic compound; the reaction equation is shown below:

[0021] Its 1H NMR data are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 10.60 (s, 1H),3.80 – 3.59 (m, 18H), 3.47 (td, J = 8.7, 7.3 Hz, 6H), 2.62 – 2.46 (m, 4H),1.81 – 1.49 (m, 10H), 1.42 – 1.20 (m, 36H), 0.92 – 0.84 (m, 6H).

[0022] S4: Add 1000 mL of toluene, 0.41 mol of a zwitterionic compound, 0.42 mol of DCC (N,N'-dicyclohexylcarbodiimide), and 0.01 mol of DMAP (4-dimethylaminopyridine) to the reactor. Heat to 60 °C and stir for 10 min to mix thoroughly. Then add 0.1 mol of the tetra-arm compound and heat to 90 °C. After reacting for 8 h, lower the temperature to 0 °C and slowly add saturated sodium bicarbonate solution to adjust the pH to 7. Stir thoroughly for 30 min, allow to stand and separate into layers, heat the organic phase to 70 °C, filter, and then transfer to a rotary evaporator. Evaporate at 70 °C for 3 h and dry under vacuum at 70 °C for 10 h to obtain the dispersant. The reaction equation is shown below:

[0023] Its 1H NMR data are as follows: 1H NMR (400 MHz, Chloroform-d) δ 5.44 – 5.29 (m,16H), 4.21 (s, J = 6.3, 5.5 Hz, 8H), 3.87 – 3.61 (m, 80H), 3.57 (t, J = 8.7Hz, 16H), 3.36 (td, J = 10.5, 0.6 Hz, 8H), 2.59 (td, J = 6.5, 4.3 Hz, 32H), 1.84 – 1.64 (m, 16H), 1.41 – 1.39 (m, 12H), 1.39 – 1.37 (m, 16H), 1.36 (d, J= 1.4 Hz, 36H), 1.32 – 1.25 (m, 128H), 0.95 – 0.77 (m, 24H).

[0024] Example 2: Preparation of dispersant: S1: Under nitrogen protection, 800 ml DMF, 0.1 mol pentaerythritol, and 1.2 mol 3,6-dimethyl-1,4-dioxane-2,5-dione were added to the reactor and stirred until homogeneous. The mixture was heated to 130 °C and stirred for 15 min. Then, 1 g of stannous octoate catalyst was added. After reacting for 24 h, the mixture was cooled to room temperature and distilled under reduced pressure at 80 °C for 2 h to obtain the crude product. The crude product was added to 500 ml chloroform and stirred until homogeneous. Then, 600 ml of cold methanol was added and allowed to stand to precipitate. The precipitate was filtered and washed three times with methanol (300 ml each time). The mixture was then dried under vacuum at 60 °C for 10 h to obtain the four-arm compound with a number average molecular weight of 1865. S2: Add 300 ml of anhydrous ethanol and 0.208 mol of 1-chlorododecane to the reactor, heat to 35 °C and stir for 20 min, add 0.22 mol of triethylamine, and then add 0.1 mol of 3-[2-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]ethoxy]propionic acid in batches (5 batches, 5 min apart), stir and mix well, heat to 65 °C and react for 7 h, filter, distill under reduced pressure at 50 °C for 2 h, then pour into 500 ml of acetone, stir to precipitate, filter, wash three times with acetone (150 ml of acetone each time), and dry under vacuum at 45 °C for 12 h to obtain the long-chain compound. S3: Add 350 mL of DMF and 0.11 mol of sodium 5-bromo-1-pentanesulfonate to the reactor, stir and mix well, then add 0.1 mol of long-chain compound in batches (5 batches, 5 min apart), heat to 75 °C, react for 9 h, cool to room temperature, slowly add to 500 mL of acetone, stir, precipitate, filter, wash three times with acetone (200 mL each time), and dry under vacuum at 45 °C for 12 h to obtain zwitterionic compound. S4: Add 1000 mL of toluene, 0.415 mol of zwitterionic compound, 0.42 mol of DCC and 0.01 mol of DMAP to the reactor, heat to 60 °C, stir for 10 min to mix evenly, then add 0.1 mol of tetra-arm compound, heat to 95 °C, react for 7 h, then cool to 0 °C, slowly add saturated sodium bicarbonate solution to adjust the pH to 7, stir thoroughly for 30 min, let stand to separate into layers, heat the organic phase to 70 °C, filter, then transfer to a rotary evaporator, rotary evaporate at 70 °C for 3 h, and vacuum dry at 70 °C for 10 h to obtain the dispersant.

[0025] Example 3: Preparation of dispersant: S1: Under nitrogen protection, 800 ml of DMF, 0.1 mol of pentaerythritol, and 1.6 mol of 3,6-dimethyl-1,4-dioxane-2,5-dione were added to the reactor and stirred until homogeneous. The mixture was heated to 130 °C and stirred for 15 min. Then, 1 g of stannous octoate catalyst was added. After reacting for 26 h, the mixture was cooled to room temperature and distilled under reduced pressure at 80 °C for 2 h to obtain the crude product. The crude product was added to 500 ml of chloroform and stirred until homogeneous. Then, 600 ml of cold methanol was added, and the mixture was allowed to stand to precipitate. The precipitate was filtered and washed three times with methanol (300 ml each time). The mixture was then dried under vacuum at 60 °C for 10 h to obtain the four-arm compound; the number average molecular weight was 2442. S2: Add 300 ml of anhydrous ethanol and 0.21 mol of 1-chlorododecane to the reactor, heat to 35 °C and stir for 20 min, add 0.23 mol of triethylamine, and then add 0.1 mol of 3-[2-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]ethoxy]propionic acid in batches (5 batches, 5 min apart), stir and mix well, heat to 70 °C and react for 6 h, filter, distill under reduced pressure at 50 °C for 2 h, then pour into 500 ml of acetone, stir to precipitate, filter, wash three times with acetone (150 ml of acetone each time), and dry under vacuum at 45 °C for 12 h to obtain the long-chain compound; S3: Add 350 mL of DMF and 0.12 mol of sodium 5-bromo-1-pentanesulfonate to the reactor, stir and mix well, then add 0.1 mol of long-chain compound in batches (5 batches, 5 min apart), heat to 80 °C, react for 8 h, cool to room temperature, slowly add to 500 mL of acetone, stir, precipitate, filter, wash three times with acetone (200 mL each time), and dry under vacuum at 45 °C for 12 h to obtain zwitterionic compound; S4: Add 1000 mL of toluene, 0.42 mol of zwitterionic compound, 0.42 mol of DCC and 0.01 mol of DMAP to the reactor, heat to 60 °C, stir for 10 min to mix evenly, then add 0.1 mol of tetra-arm compound, heat to 100 °C, react for 6 h, then cool to 0 °C, slowly add saturated sodium bicarbonate solution to adjust the pH to 7, stir thoroughly for 30 min, let stand to separate into layers, heat the organic phase to 70 °C, filter, then transfer to a rotary evaporator, rotary evaporate at 70 °C for 3 h, and vacuum dry at 70 °C for 10 h to obtain the dispersant.

[0026] Example 4: Preparation of a high-efficiency wet flue gas desulfurization agent: (1) Weigh out: organic acid (citric acid): 50g, alkaline activator (sodium hydroxide): 100g, dispersant (prepared in Example 1): 30g, catalytic oxidant (manganese sulfate): 5g; (2) At room temperature, add the above materials to the agitator 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, ball mill at 500 rpm for 30 min, stand for 15 min, and repeat the ball milling and standing process 5 times to obtain the flue gas desulfurizing agent.

[0027] Example 5: Preparation of a high-efficiency wet flue gas desulfurization agent: (1) Weigh out the following: organic acid (succinic acid): 100g, alkaline activator (sodium hydroxide): 200g, dispersant (prepared in Example 2): 60g, and catalytic oxidant (manganese sulfate): 15g; (2) At room temperature, add the above materials to the agitator 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, ball mill at 500 rpm for 30 min, stand for 15 min, and repeat the ball milling and standing process 5 times to obtain the flue gas desulfurizing agent.

[0028] Example 6: Preparation of a high-efficiency wet flue gas desulfurization agent: (1) Weigh: organic acid (adipic acid): 150g, alkaline activator (potassium hydroxide): 250g, dispersant (prepared in Example 3): 100g, catalytic oxidant (sodium iron ethylenediaminetetraacetate): 30g; (2) At room temperature, add the above materials to the agitator 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, ball mill at 500 rpm for 30 min, stand for 15 min, and repeat the ball milling and standing process 5 times to obtain the flue gas desulfurizing agent.

[0029] Comparative Example 1 The raw material composition and preparation method of the high-efficiency wet flue gas desulfurization agent are basically the same as those in Example 5, except that the dispersant is replaced with an equal weight of a dispersant prepared by the following method: The preparation method of the dispersant is basically the same as that in Example 2, except that the amount of 3,6-dimethyl-1,4-dioxane-2,5-dione added in step S1 is 3.0 mol.

[0030] Comparative Example 2 The raw material composition and preparation method of the high-efficiency wet flue gas desulfurization agent are basically the same as those in Example 5, except that the dispersant is replaced with an equal weight of a dispersant prepared by the following method: The preparation method of the dispersant is basically the same as that in Example 2, except that 1-chlorododecane in step S2 is replaced with an equimolar amount of 1-chlorohexane.

[0031] Comparative Example 3 The raw material composition and preparation method of the high-efficiency wet flue gas desulfurization agent are basically the same as those in Example 5, except that the dispersant is replaced with an equal weight of a dispersant prepared by the following method: The preparation method of the dispersant is basically the same as that in Example 2, except that the 3-[2-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]ethoxy]propionic acid in step S2 is replaced with an equimolar amount of 2-(2-(2-aminoethoxy)ethoxy)acetic acid.

[0032] Comparative Example 4 The raw material composition and preparation method of the high-efficiency wet flue gas desulfurization agent are basically the same as those in Example 5, except that the dispersant is replaced with an equal weight of a dispersant prepared by the following method: The preparation method of the dispersant is basically the same as that in Example 2, except that the 3-[2-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]ethoxy]propionic acid in step S2 is replaced with an equimolar amount of 11-aminoundecanoic acid.

[0033] Comparative Example 5 The raw material composition and preparation method of the high-efficiency wet flue gas desulfurization agent are basically the same as those in Example 5, except that the dispersant is replaced with an equal weight of a dispersant prepared by the following method: The preparation method of the dispersant is basically the same as that in Example 2, except that the sodium 5-bromo-1-pentanesulfonate in step S3 is replaced with an equimolar amount of sodium 2-chloroethylsulfonate.

[0034] Comparative Example 6 The raw material composition and preparation method of the high-efficiency wet flue gas desulfurization agent are basically the same as those in Example 5, except that the dispersant is replaced with an equal weight of a dispersant prepared by the following method: S1: Under nitrogen protection, 800 ml DMF, 0.1 mol pentaerythritol, and 1.2 mol 3,6-dimethyl-1,4-dioxane-2,5-dione were added to the reactor and stirred until homogeneous. The mixture was heated to 130 °C and stirred for 15 min. Then, 1 g of stannous octoate catalyst was added. After reacting for 24 h, the mixture was cooled to room temperature and distilled under reduced pressure at 80 °C for 2 h to obtain the crude product. The crude product was added to 500 ml chloroform and stirred until homogeneous. Then, 600 ml of cold methanol was added and allowed to stand to precipitate. The precipitate was filtered and washed three times with methanol (300 ml each time). The mixture was then dried under vacuum at 60 °C for 10 h to obtain the four-arm compound with a number average molecular weight of 1865. S2: Add 300 ml of anhydrous ethanol and 0.208 mol of 1-chlorododecane to the reactor, heat to 35 °C and stir for 20 min, add 0.22 mol of triethylamine, and then add 0.1 mol of 3-[2-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]ethoxy]propionic acid in batches (5 batches, 5 min apart), stir and mix well, heat to 65 °C and react for 7 h, filter, distill under reduced pressure at 50 °C for 2 h, then pour into 500 ml of acetone, stir to precipitate, filter, wash three times with acetone (150 ml of acetone each time), and dry under vacuum at 45 °C for 12 h to obtain the long-chain compound. S3: Add 1000 mL of toluene, 0.415 mol of long-chain compound, 0.42 mol of DCC and 0.01 mol of DMAP to the reactor, heat to 60 °C, stir for 10 min to mix evenly, then add 0.1 mol of four-arm compound, heat to 95 °C, react for 7 h, then cool to 0 °C, slowly add saturated sodium bicarbonate solution to adjust the pH to 7, stir thoroughly for 30 min, let stand to separate into layers, heat the organic phase to 70 °C, filter, then transfer to a rotary evaporator, rotary evaporate at 70 °C for 3 h, and vacuum dry at 70 °C for 10 h to obtain the dispersant.

[0035] Comparative Example 7 The raw material composition and preparation method of the high-efficiency wet flue gas desulfurization agent are basically the same as those in Example 5, except that the dispersant is replaced with an equal weight of a dispersant prepared by the following method: S1: Add 300 ml of anhydrous ethanol and 0.208 mol of 1-chlorododecane to the reactor, heat to 35 °C and stir for 20 min, add 0.22 mol of triethylamine, and then add 0.1 mol of 3-[2-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]ethoxy]propionic acid in batches (5 batches, 5 min apart), stir and mix well, heat to 65 °C and react for 7 h, filter, distill under reduced pressure at 50 °C for 2 h, then pour into 500 ml of acetone, stir to precipitate, filter, wash three times with acetone (150 ml of acetone each time), and dry under vacuum at 45 °C for 12 h to obtain the long-chain compound.

[0036] S2: Add 350 mL of DMF and 0.11 mol of sodium 5-bromo-1-pentanesulfonate to the reactor, stir and mix well, then add 0.1 mol of long-chain compound in batches (5 batches, 5 min apart), heat to 75 °C, react for 9 h, cool to room temperature, slowly add to 500 mL of acetone, stir, precipitate, filter, wash three times with acetone (200 mL each time), and dry under vacuum at 45 °C for 12 h to obtain zwitterionic compound.

[0037] S3: Add 1000 mL of toluene, 0.415 mol of zwitterionic compound, 0.42 mol of DCC and 0.01 mol of DMAP to the reactor, heat to 60 °C, stir for 10 min to mix evenly, then add 0.1 mol of pentaerythritol, heat to 95 °C, react for 7 h, then cool to 0 °C, slowly add saturated sodium bicarbonate solution to adjust the pH to 7, stir thoroughly for 30 min, let stand to separate the layers, heat the organic phase to 70 °C, filter, then transfer to a rotary evaporator, rotary evaporate at 70 °C for 3 h, and vacuum dry at 70 °C for 10 h to obtain the dispersant.

[0038] The flue gas desulfurizing agents prepared in Examples 4-6 and Comparative Examples 1-7 were subjected to limestone dissolution and flue gas desulfurization tests. The results are shown in Table 1.

[0039] Limestone dissolution test: The desulfurizing agents prepared in Examples 4-6 and Comparative Examples 1-7 were mixed evenly with 100 ml of 3 wt% limestone slurry (the final desulfurizing agent content was 1000 mg / L). The mixture was heated to 50°C and titrated with 0.1 M HCl at a rotation speed of 300 r / min. The pH of the automatic titrator was set to 5.5. The amount of hydrochloric acid used after 1 hour of titration was recorded. The solution was then obtained according to the formula... (in, The concentration of HCl; This represents the volume of hydrochloric acid consumed in 1 hour. This refers to the total mass of calcium carbonate; The solubility of limestone is calculated using the relative molecular mass of calcium carbonate.

[0040] Flue gas desulfurization test: The desulfurizing agents prepared in Examples 4-6 and Comparative Examples 1-7 were mixed evenly with 100 ml of 3 wt% limestone slurry (the final desulfurizing agent content was 1000 mg / L). Under 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 flue gas desulfurizing agent was added to the absorption tower, and 1 wt% SO2 / N2 standard gas (with nitrogen as the balance gas) 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 and calculated according to the formula... (in, This refers to the concentration of imported SO2. Calculate the desulfurization efficiency by taking the SO2 concentration at the outlet at 1 hour as the value.

[0041] Table 1 Performance Indicators of Desulfurizer

[0042] As can be seen from the data in Table 1, the flue gas desulfurizing agents prepared in Examples 4-6 of this application can effectively promote limestone dissolution and have excellent desulfurization efficiency.

[0043] The dispersant added to the high-efficiency wet flue gas desulfurization agent prepared in this application has a four-arm structure with pentaerythritol as the core, and also contains long alkyl chains, quaternary ammonium salt groups, sulfonic acid groups, ether bonds, and ester groups. When the dispersant is added to the flue gas desulfurization system, the hydrophobic long alkyl chains extend into the water, preventing particle agglomeration through steric hindrance; the quaternary ammonium salt cations can react with HSO3. - or SO3 2- It forms ion pairs, regulates surface charge distribution, improves the crystallization behavior of desulfurization byproducts (such as calcium sulfite), and reduces the risk of scaling; the hydrophilic sulfonic acid groups can significantly improve the wettability of particle surfaces, accelerate the mass transfer process of sulfur dioxide from the gas phase to the liquid phase, and promote H+ ion formation. + The migration and reaction of limestone onto the surface of the limestone particles enhances the dissolution rate and desulfurization efficiency. Simultaneously, the zwitterionic structure formed by the quaternary ammonium salt groups and sulfonic acid groups exhibits strong hydration and resistance to electrolyte interference, maintaining good stability even in high-ionic-strength desulfurization slurry environments, preventing particle sedimentation or flocculation. Flexible ether bonds enhance the hydrophilicity of the particle surface, promoting sulfur dioxide mass transfer and endowing the molecular chains with excellent conformational flexibility, thus forming a dense spatial protective layer that effectively prevents particle agglomeration and increases the reaction surface area. The synergistic effect of these multiple structures improves the dispersion stability and dissolution rate of limestone in the slurry, thereby increasing flue gas desulfurization efficiency and limestone utilization.

[0044] The dispersant used in Comparative Example 1 had an excessively high molecular weight and excessively long chain segments. Excessively long chain segments are prone to intramolecular or intermolecular entanglement and aggregation, which weakens the steric hindrance effect, reduces the dispersion effect, and ultimately makes limestone particles prone to aggregation, resulting in a decrease in solubility and desulfurization efficiency.

[0045] In Comparative Example 2, the alkyl chains in the dispersant were shortened, making it difficult to form a dense molecular adsorption layer. This resulted in insufficient steric repulsion on the surface of limestone particles, causing particle agglomeration due to van der Waals forces. This reduced the total specific surface area of ​​the reaction, preventing the limestone inside the slurry from fully contacting and reacting. Simultaneously, the slurry rheological properties deteriorated, hindering the reaction of SO2 and H2. + The reduced mass transfer efficiency to the particle surface leads to a decrease in limestone utilization and desulfurization efficiency.

[0046] The dispersant used in Comparative Example 4 lacks hydrophilic ether bonds, which disrupts the hydrophilic-lipophilic balance of the molecules. This not only results in the loss of the strong hydration and steric hindrance brought by the polyether chain, but also makes it less dispersible in the slurry due to the increased hydrophobicity. This makes it difficult to effectively prevent limestone particle agglomeration, ultimately leading to a decrease in the reaction specific surface area and mass transfer efficiency, and a decrease in desulfurization efficiency.

[0047] 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 high-efficiency wet flue gas desulfurization agent, characterized in that, The ingredients include the following parts by weight: Organic acid: 5-15 parts, alkaline activator: 10-25 parts, dispersant: 3-10 parts, catalytic oxidant: 0.5-3 parts; The dispersant is prepared by the following method: S1: Pentaerythritol reacts with 3,6-dimethyl-1,4-dioxane-2,5-dione in the presence of a catalyst to form a four-armed compound. S2: 1-Chlorododecane reacts with 3-[2-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]ethoxy]propionic acid to form a long-chain compound. S3: Long-chain compounds react with sodium 5-bromo-1-pentanesulfonate to form zwitterionic compounds. S4: A zwitterionic compound reacts with a tetrapod compound to obtain a dispersant.

2. The high-efficiency wet flue gas desulfurization agent according to claim 1, characterized in that, In step S1, the molar ratio of pentaerythritol to 3,6-dimethyl-1,4-dioxane-2,5-dione is 1:(8-16).

3. The high-efficiency wet flue gas desulfurization agent according to claim 1, characterized in that, In step S2, the molar ratio of 1-chlorododecane to 3-[2-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]ethoxy]propionic acid is (2.05-2.1):

1.

4. The high-efficiency wet flue gas desulfurization agent according to claim 1, characterized in that, In step S3, the molar ratio of the long-chain compound to sodium 5-bromo-1-pentanesulfonate is 1:(1.05-1.2).

5. The high-efficiency wet flue gas desulfurization agent according to claim 1, characterized in that, In step S4, the molar ratio of the zwitterionic compound to the tetra-armed compound is (4.1-4.2):

1.

6. The high-efficiency wet flue gas desulfurization agent according to claim 1, characterized in that, In step S1, the catalyst is stannous octoate.

7. The high-efficiency wet flue gas desulfurization agent according to claim 1, characterized in that, The organic acid is one of citric acid, succinic acid, and adipic acid.

8. The high-efficiency wet flue gas desulfurization agent according to claim 1, characterized in that, The alkaline activator is either sodium hydroxide or potassium hydroxide.

9. The high-efficiency wet flue gas desulfurization agent according to claim 1, characterized in that, The catalytic oxidant is one of manganese sulfate or sodium iron ethylenediaminetetraacetate.

10. A method for preparing the high-efficiency wet flue gas desulfurization agent according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Weigh out the following by weight: organic acid: 5-15 parts, alkaline activator: 10-25 parts, dispersant: 3-10 parts, catalytic oxidant: 0.5-3 parts; (2) Mix the above materials, stir evenly, and grind them into powder in a planetary ball mill to obtain flue gas desulfurizer.

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