A wet flue gas denitrification enhancer and its preparation method

Abstract

This invention discloses a wet flue gas denitrification enhancer and its preparation method, relating to the field of flue gas denitrification technology. The wet flue gas denitrification enhancer comprises the following raw materials in parts by weight: organic acid: 5-12 parts, metal catalyst: 1-5 parts, pH buffer: 3-10 parts, surfactant: 0.5-2 parts, and deionized water: 20-40 parts. The flue gas denitrification enhancer prepared by this invention exhibits good denitrification efficiency.

Description

Technical Field

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

[0002] Wet flue gas denitrification (FGD) technology is widely used in steel plant flue gas treatment due to its mature process, good equipment compatibility, and ability to operate in conjunction with existing wet desulfurization units. However, wet FGD generally faces a key problem: low mass transfer efficiency at the gas-liquid interface, especially significant diffusion resistance when NO2 molecules cross the gas-liquid interface. NO2 has low water solubility, limiting its mass transfer flux in the liquid phase, making it difficult for large amounts of NO2 entering the absorber to dissolve and diffuse into the internal reaction zone of the liquid in a timely manner. Due to this mass transfer limitation, although the active components such as oxidants and catalysts added in traditional processes are costly, the actual effective contact area with NO2 is limited, resulting in low reaction efficiency, insufficient utilization, and even situations where reagent consumption increases but denitrification efficiency remains insignificant. Simultaneously, the slow residence and diffusion of NO2 in the liquid film makes it even more difficult to maintain the dynamic equilibrium of the reaction between the gas and liquid phases, which is a key problem that urgently needs to be solved to improve the efficiency of wet FGD.

[0003] Chinese invention patent CN115501748A discloses a denitrification agent and its preparation method. When the denitrification agent is a particulate composite denitrification agent, it includes the following components: 50-80 parts by mass of reducing agent, 8-20 parts by mass of manganese ore powder-based denitrification catalyst, 10-30 parts by mass of denitrification synergist, and 0.5-2 parts by mass of organic binder. The denitrification agent has low ammonia slip and a denitrification temperature of 100-1100℃, but its denitrification temperature is relatively high and its denitrification efficiency still needs to be improved. Summary of the Invention

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

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

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

[0007] Organic acid: 5-12 parts, metal catalyst: 1-5 parts, pH buffer: 3-10 parts, surfactant: 0.5-2 parts, deionized water: 20-40 parts;

[0008] The structural formula of the surfactant is as follows:

[0009] .

[0010] The surfactant is prepared by the following method:

[0011] S1: Pentaerythritol reacts with epichlorohydrin in the presence of a basic catalyst to form a tetracyclic oxide compound.

[0012] S2: Tetraepoxide reacts with dodecyl heptaethylene glycol ether to form a four-armed compound.

[0013] S3: The four-armed compound reacts with 1,3-propanesulfonate lactone in the presence of a basic catalyst to generate a surfactant.

[0014] In step S1, the molar ratio of pentaerythritol to epichlorohydrin is 1:(4.05-4.1).

[0015] In step S2, the molar ratio of the tetraepoxide compound to dodecyl heptaethylene glycol ether is 1:(4.1-4.2).

[0016] In step S3, the molar ratio of the four-armed compound to 1,3-propanesulfonate lactone is 1:(4.1-4.3).

[0017] In step S1, the alkaline catalyst is potassium carbonate.

[0018] In step S3, the alkaline catalyst is sodium hydride.

[0019] The metal catalyst is manganese sulfate.

[0020] The organic acid is one of citric acid and tartaric acid.

[0021] The pH buffer is a mixture of sodium carbonate and sodium bicarbonate.

[0022] A method for preparing a wet flue gas denitrification enhancer includes the following steps:

[0023] (1) Weigh out the following by weight: organic acid: 5-12 parts, metal catalyst: 1-5 parts, pH buffer: 3-10 parts, surfactant: 0.5-2 parts, deionized water: 20-40 parts;

[0024] (2) Add deionized water to the reactor, then add organic acid and metal catalyst in sequence, and stir to mix; then add pH buffer, stir to mix, slowly add surfactant, stir to mix, and obtain wet flue gas denitrification enhancer.

[0025] Due to the adoption of the above technical solutions, the beneficial effects of the present invention include:

[0026] The denitrification enhancer prepared by this invention has a good denitrification rate. The added surfactant electrostatically enriches NO2 through sulfonic acid groups, the polyether segments form a hydrogen bond network with water molecules through their ether bonds to increase the gas-liquid contact area, and the dodecyl chain drives the interface to oriented and form a stable film. The synergistic effect of multiple functional groups significantly improves the denitrification efficiency. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the denitrification performance testing system.

[0028] Figure 2 The image shows the proton NMR spectrum of the tetraepoxide compound prepared in step S1 of Example 1.

[0029] Figure 3 The image shows a high-resolution mass spectrum of the tetracyclic oxide compound prepared in step S1 of Example 1.

[0030] Figure 4 The photon nuclear magnetic resonance (NMR) spectrum of the four-armed compound prepared in step S2 of Example 1 is shown.

[0031] Figure 5 The image shows a high-resolution mass spectrum of the four-armed compound prepared in step S2 of Example 1.

[0032] Figure 6 The image shows the proton NMR spectrum of the surfactant prepared in step S3 of Example 1.

[0033] Figure 7 This is a high-resolution mass spectrum of the surfactant prepared in step S3 of Example 1.

[0034] Figure 8 This is a schematic diagram of the preparation process for denitrification enhancers. Detailed Implementation

[0035] The following description, in conjunction with specific embodiments, provides further details, but the present invention is not limited to these embodiments.

[0036] Example 1: Preparation of surfactants:

[0037] S1: Add 200 ml DMSO (dimethyl sulfoxide), 0.1 mol pentaerythritol, and 0.405 mol epichlorohydrin to the reactor, stir to mix, and add 0.82 mol potassium carbonate in batches (4 equal batches, 5 min apart) under ice bath conditions. After reacting at room temperature for 12 h, quench the reaction with 250 ml deionized water, extract three times with dichloromethane (200 ml each time), wash the organic phase three times with saturated sodium chloride solution (100 ml each time), dry with 20 g anhydrous sodium sulfate for 1 h, filter, distill under reduced pressure at 40 °C for 3 h, slowly pour into 250 ml cold petroleum ether, stir, precipitate, filter, wash with 100 ml cold petroleum ether, and dry under vacuum at 50 °C for 10 h to obtain the tetraepoxide compound; the reaction equation is shown below:

[0038]

[0039] Its proton nuclear magnetic resonance spectrum is as follows: Figure 2 As shown, its 1H NMR spectrum data are as follows: 1 ¹H NMR (400 MHz, Chloroform-d) δ 3.73 (dd, J = 11.3, 2.5 Hz, 4H), 3.53 - 3.46 (m, 12H), 3.25 (tt, J = 3.1, 2.5 Hz, 4H), 3.08 (dd, J = 7.7, 3.1 Hz, 4H), 2.82 (dd, J = 7.7, 3.1 Hz, 4H); its high-resolution mass spectrum is shown below. Figure 3 The mass spectrometry data are as follows: HRMS (m / z): 361.1786 [M+H] + .

[0040] S2: Add 150 ml of 1,2-dichloroethane and 0.1 mol of tetraepoxide to the reactor, stir to mix, heat to 60°C, then add 0.6 g of boron trifluoride ether catalyst, and slowly add 800 ml of 1,2-dichloroethane solution containing 0.41 mol of dodecyl heptaethylene glycol ether dropwise over 1 hour. After the addition is complete, react for 5 hours, then slowly add saturated sodium carbonate solution until the pH of the solution reaches 7. Stir at room temperature for 30 minutes, allow to stand and separate into layers, wash the organic phase three times with deionized water (300 ml each time), wash once with 300 ml of saturated sodium chloride solution, dry with 50 g of anhydrous sodium sulfate, filter, distill under reduced pressure at 40°C for 3 hours, and dry under vacuum at 60°C for 8 hours to obtain the four-armed compound; the reaction equation is shown below:

[0041]

[0042] Its proton nuclear magnetic resonance spectrum is as follows: Figure 4 As shown, its 1H NMR spectrum data are as follows:1 ¹H NMR (400 MHz, Chloroform-d) δ 3.92 - 3.87 (m, 8H), 3.86 - 3.81 (m, 4H), 3.74 (d, J = 5.0 Hz, 4H), 3.70 (s, 84H), 3.69 - 3.61 (m, 24H), 3.53 - 3.43 (m, 24H), 3.24 (d, J = 6.7 Hz, 4H), 1.56 (ttd, J = 7.5, 6.1, 0.5 Hz, 8H), 1.35 - 1.24 (m, 72H), 0.92 - 0.86 (m, 12H); its high-resolution mass spectrum is shown below. Figure 5 As shown, the mass spectrometry data are as follows: HRMS (m / z): 2339.7094 [M+H] + .

[0043] S3: Under nitrogen protection, 1000 mL of tetrahydrofuran and 0.1 mol of the four-arm compound were added to the reactor and stirred to dissolve. At 0°C, 0.42 mol of sodium hydride was added in five equal batches, 4 min apart. The mixture was stirred at room temperature for 30 min. Then, 200 mL of a tetrahydrofuran solution containing 0.41 mol of 1,3-propanesulfonate lactone was slowly added dropwise over 30 min. After the addition was complete, the temperature was raised to 45°C, and the reaction was allowed to proceed for 24 h. The mixture was then cooled to 0°C in an ice bath, and 100 mL of methanol was slowly added to quench the reaction. The mixture was then distilled under reduced pressure at 40°C for 2 h to obtain the crude product. The crude product was dissolved in 600 mL of acetone at 60°C, and the mixture was slowly cooled to room temperature. Then, 900 mL of anhydrous diethyl ether was slowly added, and the mixture was stirred to precipitate the precipitate. The precipitate was filtered and washed three times (200 mL each time) with a cold mixture of diethyl ether and acetone (v / v = 10:1). The product was then dried under vacuum at 40°C for 12 h to obtain the surfactant. The reaction equation is shown below.

[0044]

[0045] Its proton nuclear magnetic resonance spectrum is as follows: Figure 6 As shown, its 1H NMR spectrum data are as follows: 1¹H NMR (400 MHz, Chloroform-d) δ 4.03 - 3.93 (m, 8H), 3.91 - 3.87 (m, 8H), 3.83 - 3.78 (m, 4H), 3.77 - 3.72 (m, 12H), 3.70 (s, 88H), 3.65 - 3.60 (m, 12H), 3.53 - 3.46 (m, 24H), 3.21 - 3.13 (m, 8H), 2.09 - 1.96 (m, 8H), 1.61 - 1.51 (m, 8H), 1.37 - 1.23 (m, 72H), 0.93 - 0.84 (m, 12H); its high-resolution mass spectrum is shown below. Figure 7 The mass spectrometry data are as follows: HRMS (m / z): 705.6739 [M-4Na] 4- .

[0046] Example 2: Preparation of surfactants:

[0047] S1: Add 200 ml DMSO, 0.1 mol pentaerythritol, and 0.408 mol epichlorohydrin to the reactor, stir and mix well. Under ice bath conditions, add 0.82 mol potassium carbonate in batches (4 batches, 5 min apart). After reacting at room temperature for 13 h, add 250 ml deionized water to quench the reaction. Extract three times with dichloromethane (200 ml each time). Wash the organic phase three times with saturated sodium chloride solution (100 ml each time). Dry with 20 g anhydrous sodium sulfate for 1 h, filter, distill under reduced pressure at 40 °C for 3 h, slowly pour into 250 ml cold petroleum ether, stir, precipitate, filter, wash with 100 ml cold petroleum ether, and dry under vacuum at 50 °C for 10 h to obtain tetraepoxide.

[0048] S2: Add 150 ml of 1,2-dichloroethane and 0.1 mol of tetraepoxide to the reactor, stir and mix well, heat to 65 °C, then add 0.6 g of boron trifluoride ether catalyst, and slowly add 800 ml of 1,2-dichloroethane solution containing 0.415 mol of dodecyl heptaethylene glycol ether dropwise over 1 hour. After the addition is complete, react for 4 hours, then slowly add saturated sodium carbonate solution until the pH of the solution is 7. Stir at room temperature for 30 minutes, allow to stand and separate into layers, wash the organic phase three times with deionized water (300 ml each time), wash once with 300 ml of saturated sodium chloride solution, add 50 g of anhydrous sodium sulfate to dry, filter, distill under reduced pressure at 40 °C for 3 hours, and dry under vacuum at 60 °C for 8 hours to obtain the tetra-armed compound;

[0049] S3: Under nitrogen protection, 1000 ml of tetrahydrofuran and 0.1 mol of the four-arm compound were added to the reactor and stirred to dissolve. At 0°C, 0.42 mol of sodium hydride was added in batches (5 batches, 4 min apart). The mixture was stirred at room temperature for 30 min. 200 mL of tetrahydrofuran solution containing 0.42 mol of 1,3-propanesulfonate lactone was slowly added dropwise over 30 min. After the addition was complete, the temperature was raised to 50°C and the reaction was carried out for 23 h. The mixture was then cooled to 0°C in an ice bath and quenched by slowly adding 100 ml of methanol. The mixture was then distilled under reduced pressure at 40°C for 2 h to obtain the crude product. 600 ml of acetone at 60°C was added to dissolve the crude product. The mixture was slowly cooled to room temperature, and then 900 ml of anhydrous diethyl ether was slowly added. The mixture was stirred, and the precipitate was precipitated. The precipitate was filtered and washed three times (200 ml each time) with a cold diethyl ether and acetone mixture (v / v = 10:1). The product was then dried under vacuum at 40°C for 12 h to obtain the surfactant.

[0050] Example 3: Preparation of surfactants:

[0051] S1: Add 200 ml DMSO, 0.1 mol pentaerythritol, and 0.41 mol epichlorohydrin to the reactor, stir and mix well. Under ice bath conditions, add 0.82 mol potassium carbonate in batches (divided into 4 batches, with a 5-min interval between batches). After reacting at room temperature for 14 h, add 250 ml deionized water to quench the reaction. Extract three times with dichloromethane (200 ml each time). Wash the organic phase three times with saturated sodium chloride solution (100 ml each time), dry with 20 g anhydrous sodium sulfate for 1 h, distill under reduced pressure at 40 °C for 3 h, slowly pour into 250 ml cold petroleum ether, stir, precipitate, filter, wash with 100 ml cold petroleum ether, and dry under vacuum at 50 °C for 10 h to obtain tetraepoxide.

[0052] S2: Add 150 ml of 1,2-dichloroethane and 0.1 mol of tetraepoxide to the reactor, stir and mix well, heat to 70 °C, then add 0.6 g of boron trifluoride ether catalyst, and slowly add 800 ml of 1,2-dichloroethane solution containing 0.42 mol of dodecyl heptaethylene glycol ether dropwise over 1 hour. After the addition is complete, react for 3 hours, then slowly add saturated sodium carbonate solution until the pH of the solution is 7. Stir at room temperature for 30 minutes, allow to stand and separate into layers, wash the organic phase three times with deionized water (300 ml each time), wash once with 300 ml of saturated sodium chloride solution, dry with 50 g of anhydrous sodium sulfate, filter, distill under reduced pressure at 40 °C for 3 hours, and dry under vacuum at 60 °C for 8 hours to obtain the tetra-armed compound;

[0053] S3: Under nitrogen protection, 1000 ml of tetrahydrofuran and 0.1 mol of the four-arm compound were added to the reactor and stirred to dissolve. At 0°C, 0.42 mol of sodium hydride was added in batches (5 batches, 4 min apart). The mixture was stirred at room temperature for 30 min. 200 mL of tetrahydrofuran solution containing 0.43 mol of 1,3-propanesulfonate lactone was slowly added dropwise over 30 min. After the addition was complete, the temperature was raised to 55°C and the reaction was carried out for 22 h. The mixture was then cooled to 0°C in an ice bath and quenched by slowly adding 100 ml of methanol. The mixture was then distilled under reduced pressure at 40°C for 2 h to obtain the crude product. 600 ml of acetone at 60°C was added to dissolve the crude product. The mixture was slowly cooled to room temperature, and then 900 ml of anhydrous diethyl ether was slowly added. The mixture was stirred, and the precipitate was precipitated. The precipitate was filtered and washed three times (200 ml each time) with a cold mixture of diethyl ether and acetone (v / v = 10:1). The product was then dried under vacuum at 40°C for 12 h to obtain the surfactant.

[0054] Example 4: Preparation of wet flue gas denitrification enhancer:

[0055] (1) Weigh: organic acid (citric acid): 50g, metal catalyst (manganese sulfate): 10g, pH buffer (28g sodium bicarbonate + 2g sodium carbonate): 30g, surfactant (prepared in Example 1): 5g, deionized water: 200g;

[0056] (2) At room temperature, add deionized water to the reactor, then add organic acid and metal catalyst in sequence, stir at 200 rpm for 30 min to form a metal complex solution; add pH buffer to the metal complex solution, stir at 500 rpm for 1 h to form a metal complex solution, then slowly add surfactant, stir at 300 rpm for 20 min to form a metal complex solution.

[0057] Example 5: Preparation of wet flue gas denitrification enhancer:

[0058] (1) Weigh: organic acid (tartaric acid): 100g, metal catalyst (manganese sulfate): 30g, pH buffer (56g sodium bicarbonate + 4g sodium carbonate): 60g, surfactant (prepared in Example 2): 10g, deionized water: 300g;

[0059] (2) At room temperature, deionized water is added to the reactor, followed by organic acid and metal catalyst. The mixture is stirred at 200 rpm for 30 min to form a metal complex solution. A pH buffer is added to the metal complex solution, and the mixture is stirred at 500 rpm for 1 h. Then, a surfactant is slowly added, and the mixture is stirred at 300 rpm for 20 min to obtain a wet flue gas denitrification enhancer.

[0060] Example 6: Preparation of wet flue gas denitrification enhancer:

[0061] (1) Weigh: organic acid (tartaric acid): 120g, metal catalyst (manganese sulfate): 50g, pH buffer (94g sodium bicarbonate + 6g sodium carbonate): 100g, surfactant (prepared in Example 3): 20g, deionized water: 400g;

[0062] (2) At room temperature, add deionized water to the reactor, then add organic acid and metal catalyst in sequence, stir at 200 rpm for 30 min to form a metal complex solution; add pH buffer to the metal complex solution, stir at 500 rpm for 1 h to form a metal complex solution, then slowly add surfactant, stir at 300 rpm for 20 min to form a metal complex solution.

[0063] Comparative Example 1

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

[0065] S1: Add 200 ml DMSO, 0.1 mol dipentaerythritol, and 0.608 mol epichlorohydrin to the reactor, stir and mix well. Under ice bath conditions, add 1.2 mol potassium carbonate in batches (divided into 4 batches, with a 5-min interval between batches). After reacting at room temperature for 13 h, add 250 ml deionized water to quench the reaction. Extract three times with dichloromethane (200 ml each time). Wash the organic phase three times with saturated sodium chloride solution (100 ml each time). Dry with 20 g anhydrous sodium sulfate for 1 h, filter, distill under reduced pressure at 40 °C for 3 h, slowly pour into 250 ml cold petroleum ether, stir, precipitate, filter, wash with 100 ml cold petroleum ether, and dry under vacuum at 50 °C for 10 h to obtain hexacyclooxygenated compound.

[0066] S2: Add 150 ml of 1,2-dichloroethane and 0.1 mol of hexacyclic oxide to the reactor, stir and mix well, heat to 65℃, then add 0.6 g of boron trifluoride ether catalyst, and slowly add 800 ml of 1,2-dichloroethane solution containing 0.615 mol of dodecyl heptaethylene glycol ether dropwise over 1 hour. After the addition is complete, react for 4 hours, then slowly add saturated sodium carbonate solution until the pH of the solution is 7. Stir at room temperature for 30 minutes, allow to stand and separate into layers, wash the organic phase three times with deionized water (300 ml each time), wash once with 300 ml of saturated sodium chloride solution, dry with 50 g of anhydrous sodium sulfate, filter, distill under reduced pressure at 40℃ for 3 hours, and dry under vacuum at 60℃ for 8 hours to obtain the hexacyclic compound.

[0067] S3: Under nitrogen protection, 1000 ml of tetrahydrofuran and 0.1 mol of the six-arm compound were added to the reactor and stirred to dissolve. At 0°C, 0.62 mol of sodium hydride was added in batches (5 batches, 4 min apart). The mixture was stirred at room temperature for 30 min. 200 mL of tetrahydrofuran solution containing 0.62 mol of 1,3-propanesulfonate lactone was slowly added dropwise over 30 min. After the addition was complete, the temperature was raised to 50°C and the reaction was carried out for 23 h. The mixture was then cooled to 0°C in an ice bath and quenched by slowly adding 100 ml of methanol. The mixture was then distilled under reduced pressure at 40°C for 2 h to obtain the crude product. 600 ml of acetone at 60°C was added to dissolve the crude product. The mixture was slowly cooled to room temperature, and then 900 ml of anhydrous diethyl ether was slowly added. The mixture was stirred, and the precipitate was precipitated. The precipitate was filtered and washed three times (200 ml each time) with a cold diethyl ether and acetone mixture (v / v = 10:1). The product was then dried under vacuum at 40°C for 12 h to obtain the surfactant.

[0068] Comparative Example 2

[0069] The raw material composition and preparation method of the wet flue gas denitrification enhancer are basically the same as those in Example 5, except that the surfactant is replaced with an equal weight of a surfactant prepared by the following method:

[0070] The preparation method of the surfactant is basically the same as that in Example 2, except that pentaerythritol in step S1 is replaced with an equimolar amount of 1,1,1-tris(hydroxymethyl)ethane.

[0071] Comparative Example 3

[0072] The raw material composition and preparation method of the wet flue gas denitrification enhancer are basically the same as those in Example 5, except that the surfactant is replaced with an equal weight of a surfactant prepared by the following method:

[0073] The preparation method of the surfactant is basically the same as that in Example 2, except that the dodecyl heptaethylene glycol ether in step S2 is replaced with an equimolar amount of triethylene glycol ethyl ether.

[0074] Comparative Example 4

[0075] The raw material composition and preparation method of the wet flue gas denitrification enhancer are basically the same as those in Example 5, except that the surfactant is replaced with an equal weight of a surfactant prepared by the following method:

[0076] The preparation method of the surfactant is basically the same as that in Example 2, except that the dodecyl heptaethylene glycol ether in step S2 is replaced with an equimolar amount of dodecyl alcohol.

[0077] Comparative Example 5

[0078] The raw material composition and preparation method of the wet flue gas denitrification enhancer are basically the same as those in Example 5. The difference is that the surfactant is replaced with an equal weight of the four-armed compound prepared by step S2 of Example 2.

[0079] The denitrification synergists prepared in Examples 4-6 and Comparative Examples 1-5 were tested, and the results are shown in Table 1.

[0080] Flue gas denitrification test: An experimental group and a control group were set up for the denitrification test. In the experimental group, 1.5g of the denitrification synergist prepared in Examples 4-6 and Comparative Examples 1-5 were added to 250ml of 0.008mol / L Na2SO3 solution and stirred to prepare the absorption solution. The control group used 250ml of 0.008mol / L Na2SO3 solution as the absorption solution.

[0081] The test method is as follows: The absorbent was placed in a bubbling reactor, and nitrogen gas containing 500 ppm NO2 and 5 vol% O2 was introduced as flue gas for the denitrification experiment. The flue gas flow rate was 0.6 L / min, and the test temperature was 50℃. The NO2 concentration at the reactor inlet and outlet was continuously monitored using a flue gas analyzer. The NO2 concentration at the inlet was 500 ppm, and the NO2 concentration in the outlet flue gas was continuously monitored for 10 minutes. The average denitrification efficiency was calculated using the following formula:

[0082] ,

[0083] Among them, C in For the imported NO2 concentration, C out t1 represents the NO2 concentration at the outlet, t2 represents the start time of the absorption experiment, and t2 represents the end time of the absorption experiment.

[0084] Table 1 Performance Indicators of Denitrification Synergists

[0085]

[0086] As can be seen from the data in Table 1, the denitrification enhancers prepared in Examples 4-6 of this application have excellent denitrification efficiency.

[0087] The denitrification enhancer prepared in this application has a significant promoting effect on NO2 absorption. The main denitrification mechanism of Na2SO3 is: SO3 produced by the hydrolysis of Na2SO3. 2- HSO3 -It can react rapidly with NO2, thus promoting the denitrification reaction and improving the NO2 removal efficiency. The surfactant prepared in this application significantly promotes the mass transfer and reaction rate of NO2 from the gas phase to the liquid phase, for the following reasons: the surfactant is based on pentaerythritol, and also incorporates sulfonate, polyether segments, and dodecyl long chains. In this surfactant, the sulfonate salt ionizes in the aqueous phase to generate sulfonate anions, which adsorb and enrich NO2 molecules in the flue gas through dipole-ion interactions, effectively enriching and concentrating the local concentration of NO2 at the gas-liquid interface, thus promoting subsequent absorption and reaction. The polyether segment contains numerous ether bonds, and the ether oxygen atoms possess lone pair electrons that can form weak coordination with nitrogen atoms in NO2 molecules, further enhancing the NO2 capture ability. Simultaneously, the ether bonds can form a hydrogen bond network with water molecules, significantly improving solution wettability and spreadability, and increasing the gas-liquid contact area. The terminal dodecyl chain, as a strongly hydrophobic group, not only drives the molecules to oriented at the gas-liquid interface through hydrophobic interactions, forming a dense monolayer and reducing surface tension, but also interacts with hydrophobic components in the flue gas through hydrophobic-hydrophobic interactions, causing the active groups carried by the surfactant (such as sulfonate groups) to accumulate at the gas-liquid interface, thereby achieving NO2 removal. Through the synergistic effect of its functional groups, this surfactant improves the mass transfer efficiency of NO2 from the gas phase to the liquid phase, thus enhancing the denitrification efficiency.

[0088] The surfactant molecules used in Comparative Example 1 have increased polarity, making them more likely to dissolve in the aqueous phase rather than accumulate at the gas-liquid interface. This weakens their ability to reduce surface tension and promote mass transfer of NO2 gas in the liquid film, ultimately leading to a decrease in denitrification efficiency.

[0089] In Comparative Example 2, the surfactant used was changed from four arms to three arms, which reduced the symmetry of the molecules and decreased the efficiency and order of self-assembly at the gas-liquid interface. This resulted in a less dense interfacial film, which reduced the dispersion and mass transfer promotion effect of the denitrification enhancer, ultimately leading to a decrease in denitrification efficiency.

[0090] The surfactant used in Comparative Example 4 lost its ability to weakly coordinate with NO2 molecules through ether bonds due to the absence of polyether chains. The shorter and more rigid molecular structure disrupted its amphiphilic balance and spatial flexibility, resulting in the inability of the molecule to form a dense and stable monolayer at the gas-liquid interface. This reduced its effect of lowering surface tension and increasing contact area, and also weakened the spatial synergistic effect between the sulfonate group and the dodecyl group, making it difficult to effectively enrich NO2, ultimately leading to a decrease in denitrification efficiency.

[0091] 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 wet flue gas denitration synergist, characterized by, The ingredients include the following parts by weight: Organic acid: 5-12 parts, metal catalyst: 1-5 parts, pH buffer: 3-10 parts, surfactant: 0.5-2 parts, deionized water: 20-40 parts; The structural formula of the surfactant is as follows: 。 2. The wet flue gas denitration synergist according to claim 1, characterized in that, The surfactant is prepared by the following method: S1: Pentaerythritol reacts with epichlorohydrin in the presence of a basic catalyst to form a tetracyclic oxide compound. S2: Tetraepoxide reacts with dodecyl heptaethylene glycol ether to form a four-armed compound. S3: The four-armed compound reacts with 1,3-propanesulfonate lactone under the action of an alkaline catalyst to generate a surfactant.

3. The wet flue gas denitration synergist according to claim 2, characterized in that, In step S1, the molar ratio of pentaerythritol to epichlorohydrin is 1:(4.05-4.1).

4. The wet flue gas denitration synergist according to claim 2, characterized in that, In step S2, the molar ratio of the tetraepoxide compound to dodecyl heptaethylene glycol ether is 1:(4.1-4.2).

5. The wet flue gas denitrification enhancer according to claim 2, characterized in that, In step S3, the molar ratio of the four-armed compound to 1,3-propanesulfonate lactone is 1:(4.1-4.3).

6. The wet flue gas denitrification enhancer according to claim 2, characterized in that, In step S1, the alkaline catalyst is potassium carbonate.

7. The wet flue gas denitrification enhancer according to claim 2, characterized in that, In step S3, the alkaline catalyst is sodium hydride.

8. The wet flue gas denitrification enhancer according to claim 1, characterized in that, The metal catalyst is manganese sulfate.

9. The wet flue gas denitrification enhancer according to claim 1, characterized in that, The organic acid is one of citric acid and tartaric acid; the pH buffer is a mixture of sodium carbonate and sodium bicarbonate.

10. A method for preparing the wet flue gas denitrification enhancer according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Weigh out the following by weight: organic acid: 5-12 parts, metal catalyst: 1-5 parts, pH buffer: 3-10 parts, surfactant: 0.5-2 parts, deionized water: 20-40 parts; (2) Add deionized water to the reactor, then add organic acid and metal catalyst in sequence and stir to mix; then add pH buffer and stir to mix; slowly add surfactant and stir to mix, and then obtain wet flue gas denitrification enhancer.

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