A flue gas desulfurization and denitrification enhancer and its preparation method
By preparing a flue gas desulfurization and denitrification enhancer, and utilizing quaternary ammonium salt compounds to improve gas-liquid interface contact and dispersibility, the problem of low desulfurization and denitrification efficiency under high-sulfur coal was solved, achieving ultra-low emissions and high-efficiency desulfurization and denitrification effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XUZHOU HUAHONG SPECIAL STEEL CO LTD
- Filing Date
- 2026-06-01
- Publication Date
- 2026-06-30
AI Technical Summary
Existing flue gas desulfurization and denitrification technologies are difficult to achieve ultra-low emissions when using high-sulfur coal. Traditional desulfurization devices have excessive SO2 concentrations and insufficient denitrification efficiency, making it difficult to meet stringent environmental protection requirements.
A flue gas desulfurization and denitrification enhancer was prepared, comprising a metal catalyst, an enhancer, a metal salt, an organic acid, a dispersant, and a persulfate. A quaternary ammonium salt compound was formed by using a specific molar ratio and ball milling process to improve the gas-liquid interface contact efficiency and dispersibility, thereby synergistically promoting the removal of SO2 and NOx.
It improves the dissolution rate of calcium carbonate, enhances the oxidation rate of calcium sulfite, significantly improves the efficiency of flue gas desulfurization and denitrification, reduces maintenance costs, and meets ultra-low emission standards.
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Figure CN122298197A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of flue gas desulfurization and denitrification technology, specifically to a flue gas desulfurization and denitrification enhancer and its preparation method. Background Technology
[0002] Currently, coal still occupies an important position in the energy structure. To control SO2 and NO emissions from coal-fired power plants... x Flue gas desulfurization and denitrification technologies are widely used to address pollutant content such as SO2 and NO2. However, in practical applications, this technology faces numerous challenges. On the one hand, due to the widespread use of high-sulfur coal, the SO2 concentration in flue gas significantly exceeds system design standards, making it difficult for traditional desulfurization devices to achieve ultra-low emission targets. On the other hand, existing denitrification technologies struggle with high concentrations of NO2. x The existing equipment is ineffective in meeting increasingly stringent environmental requirements. To address these issues, without modifying the original equipment, adding a desulfurization and denitrification synergist to the limestone slurry can not only effectively improve SO2 absorption efficiency but also synergistically promote NO absorption. x The removal of [the pollutant] effectively reduces maintenance costs and improves the overall environmental performance of the system.
[0003] Chinese invention patent CN103691288A discloses a method for manufacturing an additive for desulfurization and denitrification in limestone-gypsum desulfurization processes. The additive comprises the following components and weight percentages: 40-60% catalytic promoters, 20-40% organic acids and salts, and 15-40% synergists. This additive can improve the desulfurization efficiency of the absorption tower, promote limestone dissolution, reduce limestone usage, and simultaneously reduce NO content in flue gas; however, its denitrification efficiency remains insufficient. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a flue gas desulfurization and denitrification enhancer and its preparation method.
[0005] To achieve the above objectives, the present invention provides the following technical solution: A flue gas desulfurization and denitrification enhancer comprises the following raw materials in parts by weight: 10-12 parts metal catalyst, 8-10 parts synergist / accelerator, 5-8 parts metal salt, 10-12 parts organic acid, 1-2 parts dispersant, 10-20 parts persulfate; The synergist is prepared by the following method: S1: Hexadecyl dimethyl tertiary amine reacts with epichlorohydrin to form an epoxy quaternary ammonium salt compound. The reaction equation is shown below:
[0006] S2: The epoxy quaternary ammonium salt compound reacts with 1,8-octanediamine to form a bisquaternary ammonium salt compound, and the reaction equation is shown below:
[0007] S3: The reaction of a bis-quaternary ammonium salt compound with epichlorohydrin produces a bis-tertiary amine bis-quaternary ammonium salt compound. The reaction equation is shown below:
[0008] S4: The reaction of a bis-tertiary amine bis-quaternary ammonium salt compound with 4-pyridinecarboxamide produces a synergistic promoter, and the reaction equation is shown below:
[0009] In step S1, the molar ratio of hexadecyl dimethyl tertiary amine to epichlorohydrin is 1:(1.1-1.2).
[0010] In step S2, the molar ratio of the epoxy quaternary ammonium salt compound to 1,8-octanediamine is (2.0-2.2):1.
[0011] In step S3, the molar ratio of the bisquaternary ammonium salt compound to epichlorohydrin is 1:(2.05-2.2).
[0012] In step S4, the molar ratio of the bis-tertiary amine bis-quaternary ammonium salt compound to 4-pyridine carboxamide is 1:(2.1-2.3).
[0013] The metal catalyst is one of manganese sulfate and ferrous sulfate.
[0014] The metal salt is one of sodium acetate or sodium sulfate.
[0015] The organic acid is one of citric acid and adipic acid.
[0016] The dispersant is sodium polyacrylate; the persulfate is either sodium persulfate or ammonium persulfate.
[0017] A method for preparing a flue gas desulfurization and denitrification enhancer, characterized by comprising the following steps: (1) Weigh out the following by weight: 10-12 parts of metal catalyst, 8-10 parts of synergist, 5-8 parts of metal salt, 10-12 parts of organic acid, 1-2 parts of dispersant, and 10-20 parts of persulfate; (2) Mix the metal catalyst, synergist, metal salt, organic acid, dispersant and persulfate, stir and mix thoroughly, then grind in a planetary ball mill to obtain the flue gas desulfurization and denitrification synergist.
[0018] Due to the adoption of the above technical solutions, the beneficial effects of the present invention include: The flue gas desulfurization and denitrification enhancer prepared by this invention has good desulfurization and denitrification efficiency. The added enhancer improves the desulfurization and denitrification performance through synergistic effects such as accelerating calcium carbonate dissolution, reducing gas-liquid interfacial tension, improving dispersibility, inhibiting calcium sulfite passivation, complexing transition metal ions, and enriching NO. Attached Figure Description
[0019] Figure 1 The image shows a high-resolution mass spectrum of the epoxy quaternary ammonium salt compound prepared in Example 1.
[0020] Figure 2 The image shows a high-resolution mass spectrum of the bisquaternary ammonium salt compound prepared in Example 1.
[0021] Figure 3 The high-resolution mass spectrum of the bis-tertiary amine bis-quaternary ammonium salt compound prepared in Example 1 is shown.
[0022] Figure 4 The high-resolution mass spectrum of the synergist prepared in Example 1.
[0023] Figure 5 Fourier transform infrared spectra of the epoxy quaternary ammonium salt compound, bisquaternary ammonium salt compound, bistertiary amine bisquaternary ammonium salt compound, and synergist prepared in Example 1.
[0024] Figure 6 This is a flowchart illustrating the preparation process of flue gas desulfurization and denitrification enhancement agents. 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 synergistic enhancer: S1: 800 ml of isopropanol and 1 mol of hexadecyl dimethyl tertiary amine were added to a reaction vessel and stirred until well mixed. 1.1 mol of epichlorohydrin was added dropwise over 30 min. The mixture was then heated to reflux and stirred for 10 h. After cooling to room temperature, it was distilled under reduced pressure at 65 °C for 2 h to obtain the epoxy quaternary ammonium salt compound. Its 1H NMR data are as follows: 1 ¹H NMR (300 MHz, Chloroform-d) δ 3.87 (tt, J = 6.0, 3.2 Hz, 1H), 3.78 (dd, J = 13.9, 5.8 Hz, 2H), 3.47 - 3.06 (m, 10H), 1.76 - 1.62 (m, 2H), 1.43 - 1.19 (m, 26H), 0.97 - 0.82 (m, 3H); its high-resolution mass spectrum is shown below. Figure 1 As shown, HRMS (m / z): 326.3421 [M-Cl] +The purity is 98.09%. S2: 500 ml DMF, 0.2 mol of epoxy quaternary ammonium salt compound, and 0.1 mol of 1,8-octanediamine were added to a reaction vessel, stirred and mixed, heated to 60 °C, and reacted for 12 h. 50 g of deionized water was added, and the reaction continued for another 12 h. The mixture was cooled to room temperature, distilled under reduced pressure at 60 °C for 2 h, and 300 ml acetone was added and stirred to precipitate the precipitate. The precipitate was filtered and dried under vacuum at 40 °C for 8 h to obtain the bisquaternary ammonium salt compound. Its 1H NMR data are as follows: 1 ¹H NMR (300 MHz, Chloroform-d) δ 5.83 (d, J = 6.0 Hz, 2H), 4.27–4.02 (m, 4H), 3.67–3.14 (m, 20H), 3.02–2.62 (m, 8H), 1.77–1.61 (m, 4H), 1.53–1.21 (m, 64H), 0.97–0.82 (m, 6H); its high-resolution mass spectrum is shown below. Figure 2 As shown, HRMS (m / z): 398.4237 [M-2Cl] 2+ The purity is 97.62%. S3: Under nitrogen protection, 500 ml of methanol and 0.1 mol of the bis-quaternary ammonium salt compound were added to a reaction vessel and stirred until homogeneous. 0.205 mol of epichlorohydrin was added dropwise at 0 °C over 30 min. The temperature was then raised to 45 °C and the reaction was allowed to proceed for 15 h. The mixture was then distilled under reduced pressure at 45 °C for 3 h. 300 ml of acetone was added and stirred to precipitate the precipitate. The precipitate was filtered and dried under vacuum at 40 °C for 8 h to obtain the bis-tertiary amine bis-quaternary ammonium salt compound. Its 1H NMR data are as follows: 1 ¹H NMR (300 MHz, Chloroform-d) δ 5.36 (d, J = 6.7 Hz, 2H), 4.35–3.94 (m, 4H), 3.70–3.56 (m, 6H), 3.51–3.12 (m, 20H), 3.05–2.49 (m, 12H), 1.79–1.61 (m, 4H), 1.58–1.16 (m, 64H), 0.98–0.79 (m, 6H); its high-resolution mass spectrum is shown below. Figure 3 As shown, HRMS (m / z): 490.4263 [M-2Cl] 2+ The purity is 97.02%. S4: 800 ml of acetonitrile, 0.1 mol of a bis-tertiary amine bis-quaternary ammonium salt compound, 0.21 mol of 4-pyridinecarboxamide, 0.4 mol of tripotassium phosphate, and 0.4 mol of tetrabutylammonium bromide were added to a reaction vessel, stirred and mixed, heated to 60 °C, and reacted for 24 h. After cooling to room temperature, the mixture was filtered, and the filtrate was distilled under reduced pressure at 50 °C for 2 h. The residue was recrystallized using a mixed solvent of 300 ml of ethyl acetate and anhydrous ethanol (ethyl acetate to anhydrous ethanol volume ratio of 8:2), and dried under vacuum at 60 °C for 12 h to obtain the synergistic promoter. Its 1H NMR data are as follows: 1 H NMR (300 MHz, Chloroform-d) δ 8.80 - 8.67 (m, 4H), 7.87 - 7.79 (m,4H), 7.29 - 7.19 (m, 2H), 5.36 (d, J = 6.7 Hz, 2H), 4.25 (d, J = 5.9 Hz, 4H),4.09 - 3.96 (m, 2H), 3.68 - 3.17 (m, 24H), 3.03 - 2.50 (m, 12H), 1.69 (tt, J= 9.0, 6.2 Hz, 4H), 1.56 - 1.46 (m, 4H), 1.42 - 1.22 (m, 60H), 0.93 - 0.85(m, 6H); HRMS (m / z):1223.9542[M+H] + Its high-resolution mass spectrum is as follows: Figure 4 As shown, HRMS (m / z): 576.4976 [M⁻²Cl] 2+ The purity is 96.14%.
[0027] Figure 5 Fourier transform infrared (FTIR) spectra of epoxy quaternary ammonium salt compounds, bisquaternary ammonium salt compounds, bistertiary amine bisquaternary ammonium salt compounds, and synergists / promoters. The FTIR spectra show that epoxy quaternary ammonium salt compounds exhibit wavelengths in the 3050-3000 cm⁻¹ range. -1 1250-1240cm -1 and 920-830cm -1 The characteristic peaks are the epoxy CH stretching vibration peak, the epoxy ring asymmetric stretching vibration peak, and the breathing vibration peak, respectively, at 1470-1460 cm⁻¹. -1 The peak is the methylene bending vibration peak, 1100-1000 cm⁻¹. -1 CN + Vibrational peaks; bisquaternary ammonium compounds at 3400-3200 cm⁻¹ -1 Exhibits broad and strong OH and NH stretching vibrations; the aliphatic C-Cl bonds in dichlorohydroxypropyl compounds are at 650-600 cm⁻¹. -1A distinct characteristic peak is produced at 1680-1650 cm⁻¹; the synergist produces a peak at 1680-1650 cm⁻¹. -1 1600-1450cm -1 and 1550-1520cm -1 The absorption peaks correspond to strong amide I bands, amide II bands, and pyridine ring skeletal vibrations. These characteristic absorption peaks are consistent with the target molecular structure, proving that the epoxy quaternary ammonium salt compound, the bis-quaternary ammonium salt compound, the bis-tertiary amine bis-quaternary ammonium salt compound, and the synergist have all been successfully prepared.
[0028] Example 2: Preparation of synergistic enhancer: S1: Add 800 ml of isopropanol and 1 mol of hexadecyl dimethyl tertiary amine to the reaction vessel, stir and mix well, add 1.15 mol of epichlorohydrin dropwise, and after 30 min, heat to reflux, stir for 11 h, cool to room temperature, and distill under reduced pressure at 65 °C for 2 h to obtain the epoxy quaternary ammonium salt compound. S2: Add 500 ml DMF, 0.21 mol epoxy quaternary ammonium salt compound, and 0.1 mol 1,8-octanediamine to a reaction vessel, stir and mix well, heat to 65℃, react for 11 h, add 50 g deionized water and continue the reaction for 12 h, cool to room temperature, distill under reduced pressure at 60℃ for 2 h, add 300 ml acetone and stir, precipitate, filter, and dry under vacuum at 40℃ for 8 h to obtain the bisquaternary ammonium salt compound; S3: Under nitrogen protection, 500 ml of methanol and 0.1 mol of the bis-quaternary ammonium salt compound were added to the reaction vessel and stirred until well mixed. 0.21 mol of epichlorohydrin was added dropwise at 0 °C. After the addition was completed in 30 min, the temperature was raised to 50 °C and the reaction was carried out for 12 h. The mixture was then distilled under reduced pressure at 45 °C for 3 h. 300 ml of acetone was added and stirred to precipitate the precipitate. The precipitate was filtered and dried under vacuum at 40 °C for 8 h to obtain the bis-tertiary amine bis-quaternary ammonium salt compound. S4: Add 800 ml of acetonitrile, 0.1 mol of bis-tertiary amine bis-quaternary ammonium salt compound, 0.22 mol of 4-pyridinecarboxamide, 0.4 mol of tripotassium phosphate and 0.4 mol of tetrabutylammonium bromide to a reaction vessel, stir and mix well, heat to 65 °C, react for 24 h, cool to room temperature, filter, distill the filtrate at 50 °C under reduced pressure for 2 h, recrystallize the residue using a mixed solvent of 300 ml of ethyl acetate and anhydrous ethanol (volume ratio of ethyl acetate to anhydrous ethanol is 8:2), and dry under vacuum at 60 °C for 12 h to obtain the synergistic promoter.
[0029] Example 3: Preparation of synergistic enhancer: S1: Add 800 ml of isopropanol and 1 mol of hexadecyl dimethyl tertiary amine to the reaction vessel, stir and mix well, add 1.2 mol of epichlorohydrin dropwise, and after 30 min, heat to reflux, stir for 12 h, cool to room temperature, and distill under reduced pressure at 65 °C for 2 h to obtain the epoxy quaternary ammonium salt compound. S2: Add 500 ml DMF, 0.22 mol epoxy quaternary ammonium salt compound, and 0.1 mol 1,8-octanediamine to a reaction vessel, stir and mix well, heat to 70℃, react for 10 h, add 50 g deionized water and continue the reaction for 12 h, cool to room temperature, distill under reduced pressure at 60℃ for 2 h, add 300 ml acetone and stir, precipitate, filter, and dry under vacuum at 40℃ for 8 h to obtain the bisquaternary ammonium salt compound; S3: Under nitrogen protection, 500 ml of methanol and 0.1 mol of the bis-quaternary ammonium salt compound were added to the reaction vessel and stirred until well mixed. 0.22 mol of epichlorohydrin was added dropwise at 0 °C, and the addition was completed in 30 min. The temperature was raised to 55 °C and the reaction was carried out for 10 h. The mixture was then distilled under reduced pressure at 45 °C for 3 h. 300 ml of acetone was added and stirred to precipitate the precipitate. The precipitate was filtered and dried under vacuum at 40 °C for 8 h to obtain the bis-tertiary amine bis-quaternary ammonium salt compound. S4: Add 800 ml of acetonitrile, 0.1 mol of bis-tertiary amine bis-quaternary ammonium salt compound, 0.23 mol of 4-pyridinecarboxamide, 0.4 mol of tripotassium phosphate and 0.4 mol of tetrabutylammonium bromide to a reaction vessel, stir and mix well, heat to 70 °C, react for 24 h, cool to room temperature, filter, distill the filtrate at 50 °C under reduced pressure for 2 h, recrystallize the residue using a mixed solvent of 300 ml of ethyl acetate and anhydrous ethanol (volume ratio of ethyl acetate to anhydrous ethanol is 8:2), and dry under vacuum at 60 °C for 12 h to obtain the synergistic promoter.
[0030] Example 4: Preparation of flue gas desulfurization and denitrification enhancer: (1) Weigh out: 100g of metal catalyst (manganese sulfate), 80g of synergist (prepared in Example 1), 50g of metal salt (sodium acetate), 100g of organic acid (citric acid), 10g of dispersant (sodium polyacrylate), and 100g of persulfate (sodium persulfate); (2) Mix the above materials and stir at 300 r / min for 20 min at room temperature; add the mixed materials into 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, grind at 500 r / min for 15 min, stop for 15 min, and grind again at 500 r / min for 15 min to obtain the flue gas desulfurization and denitrification enhancer.
[0031] Example 5: Preparation of flue gas desulfurization and denitrification enhancer: (1) Weigh out: 110g of metal catalyst (ferrous sulfate), 90g of synergist (prepared in Example 2), 60g of metal salt (sodium acetate), 110g of organic acid (adipic acid), 15g of dispersant (sodium polyacrylate), and 150g of persulfate (ammonium persulfate); (2) Mix the above materials and stir at 300 r / min for 20 min at room temperature; add the mixed materials into 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, grind at 500 r / min for 15 min, stop for 15 min, and grind again at 500 r / min for 15 min to obtain the flue gas desulfurization and denitrification enhancer.
[0032] Example 6: Preparation of flue gas desulfurization and denitrification enhancer: (1) Weigh out: 120g of metal catalyst (ferrous sulfate), 100g of synergist (prepared in Example 3), 80g of metal salt (sodium sulfate), 120g of organic acid (adipic acid), 20g of dispersant (sodium polyacrylate), and 200g of persulfate (ammonium persulfate); (2) Mix the above materials and stir at 300 r / min for 20 min at room temperature; add the mixed materials into 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, grind at 500 r / min for 15 min, stop for 15 min, and grind again at 500 r / min for 15 min to obtain the flue gas desulfurization and denitrification enhancer.
[0033] Comparative Example 1 The raw material composition and preparation method of the flue gas desulfurization and denitrification enhancer are basically the same as those in Example 5. The difference is that the enhancer is replaced with an equal weight of the bis-tertiary amine bis-quaternary ammonium salt compound prepared by step S3 of Example 2.
[0034] Comparative Example 2 The raw material composition and preparation method of the flue gas desulfurization and denitrification enhancer are basically the same as those in Example 5, except that the enhancer is replaced with an equal weight of the enhancer prepared by the following method: The preparation method of the synergist is basically the same as that in Example 2, except that the hexadecyl dimethyl tertiary amine in step S1 is replaced with an equimolar amount of N,N-dimethyl butylamine.
[0035] Comparative Example 3 The raw material composition and preparation method of the flue gas desulfurization and denitrification enhancer are basically the same as those in Example 5, except that the enhancer is replaced with an equal weight of the enhancer prepared by the following method: The preparation method of the synergist is basically the same as that in Example 2, except that 1,8-octanediamine in step S2 is replaced with an equimolar amount of ethylenediamine.
[0036] Comparative Example 4 The raw material composition and preparation method of the flue gas desulfurization and denitrification enhancer are basically the same as those in Example 5, except that the enhancer is replaced with an equal weight of the enhancer prepared by the following method: The preparation method of the synergist is basically the same as that in Example 2, except that 1,8-octanediamine in step S2 is replaced with an equimolar amount of 1,12-diaminododecane.
[0037] Comparative Example 5 The raw material composition and preparation method of the flue gas desulfurization and denitrification enhancer are basically the same as those in Example 5, except that the enhancer is replaced with an equal weight of the enhancer prepared by the following method: The preparation method of the synergist is basically the same as that in Example 2, except that 4-pyridinecarboxamide in step S4 is replaced with an equimolar amount of 2-pyridinecarboxamide.
[0038] Comparative Example 6 The raw material composition and preparation method of the flue gas desulfurization and denitrification enhancer are basically the same as those in Example 5. The difference is that the enhancer is replaced with an equal weight of CTAB.
[0039] The number-average molecular weight of sodium polyacrylate used in this application is 3800.
[0040] The flue gas desulfurization and denitrification enhancers prepared in Examples 4-6 and Comparative Examples 1-6 of this application were subjected to limestone dissolution rate, calcium sulfite oxidation rate, flue gas desulfurization, and flue gas denitrification tests. The test results are shown in Table 1.
[0041] Limestone dissolution test: The flue gas desulfurization and denitrification enhancer prepared in the examples and comparative examples was mixed evenly with 100 ml of 3 wt% limestone slurry (the content of the flue gas desulfurization and denitrification enhancer was 500 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 value of the automatic titrator was set to 5.5. The titration was recorded continuously for 1 h. The limestone dissolution rate was calculated using the following formula:
[0042] Where c is the molar concentration of HCl; v is the volume of hydrochloric acid consumed in 1 hour; m is the total mass of limestone; and Mn is the relative molecular mass of limestone.
[0043] Calcium sulfite oxidation rate test: The flue gas desulfurization and denitrification enhancer prepared in the examples and comparative examples was mixed evenly with 100 ml of 1 wt% CaSO3 (the content of the flue gas desulfurization and denitrification enhancer was 500 mg / L), and 1 ml of 36 wt% concentrated hydrochloric acid was added and mixed evenly. The experimental temperature was set at 50℃, the rotation speed at 300 r / min, and a mixed gas of nitrogen, oxygen, and carbon dioxide (ratio of 4:1:5) was introduced at a total flow rate of 0.2 L / min. After introducing the mixed gas for 5 min, the SO4 in the solution was measured using an automatic potentiometric titrator equipped with a lead nitrate electrode. 2- The concentration of C0 was measured again after 60 minutes. 2- Concentration C1; Calculate the oxidation rate of CaSO3 using the following formula:
[0044] Where C1 is the sulfate concentration at 60 min, in μmol / L; C0 is the initial sulfate concentration, in μmol / L; and t is the time, in s.
[0045] The flue gas desulfurization and denitrification tests were conducted through the following steps: The flue gas desulfurization and denitrification enhancers prepared in the examples and comparative examples were mixed evenly with 100 ml of 3 wt% limestone slurry (the content of the flue gas desulfurization and denitrification enhancer was 500 mg / L), the temperature was controlled at 50℃, the stirring speed was 500 r / min, and the mixture was stirred for 4 hours; the limestone slurry with added desulfurization and denitrification enhancers was added to the absorption tower, and the desulfurization performance was tested: the inlet flue gas SO2 concentration was set at 3000 mg / Nm³. 3 (The equilibrium gas is nitrogen), the liquid-to-gas ratio is 10.5, and the concentration of SO2 in the outlet flue gas is monitored; the denitrification performance test method is the same as the desulfurization performance test method, except that the inlet flue gas is replaced with a concentration of 1000 mg / Nm³. 3 The NO concentration in the outlet flue gas is monitored (with nitrogen as the balance gas). The desulfurization and denitrification efficiencies are calculated using the following formula:
[0046] Among them, C in The SO2 / NO concentration at the inlet, C out The SO2 / NO concentration at the outlet.
[0047] Table 1 Performance Test Data
[0048] As can be seen from Table 1, the flue gas desulfurization and denitrification enhancers prepared in Examples 4-6 of this application can promote the dissolution of calcium carbonate, increase the oxidation rate of calcium sulfite, and exhibit good desulfurization and denitrification efficiency.
[0049] The synergist added to the desulfurization and denitrification synergist of this invention contains a quaternary ammonium salt cation, a hydroxyl group, a long-chain alkyl group, and a pyridine structure. The quaternary ammonium salt cation and the hydrophobic long-chain alkyl group work synergistically to orient the synergist at the gas-liquid interface, reducing the surface tension of the slurry, increasing the gas-liquid contact area, and promoting the mass transfer rate of SO2 / NO from the gas phase to the liquid phase. The hydrophobic long-chain alkyl group can also encapsulate undissolved calcium carbonate particles, preventing particle agglomeration and maintaining a uniform dispersion of the slurry. The hydroxyl group, through hydrogen bonding, improves the dispersibility and solubility of the synergist in the aqueous phase, ensuring uniform distribution of the active components. It can also form hydrogen bonds or coordination with calcium sulfite, inhibiting the formation of its surface passivation layer and promoting oxygen diffusion into the interior. The nitrogen atom in the pyridine structure has a lone pair of electrons, which can interact with transition metal ions (such as Fe). 2+ Mn 2+ The pyridine structure forms a highly active complex, accelerating the electron transfer process from dissolved oxygen to sulfite, thus increasing the oxidation rate of calcium sulfite. Furthermore, the pyridine structure, through π-π stacking, enriches NO at the gas-liquid interface and promotes NO reduction, thereby enhancing denitrification efficiency. The synergistic effect of multiple functional groups in the synergist promotes the dissolution of calcium carbonate and increases the oxidation rate of calcium sulfite, resulting in excellent desulfurization and denitrification efficiency.
[0050] The synergist added in Comparative Example 3 had a short connecting bridge (-C2H4-) and an overly compact molecular structure, resulting in uneven distribution of active sites and poor desulfurization and denitrification effects. The synergist added in Comparative Example 4 had a longer connecting bridge (-C... 12 H 24 -), which easily induces self-coiling to embed active sites, resulting in poor desulfurization and denitrification effects. The amide group of the synergist added in Comparative Example 5 easily forms intramolecular hydrogen bonds with the ortho-N, making it difficult to effectively bind with metal ions and reducing the desulfurization and denitrification effect.
[0051] 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 and denitrification synergist, characterized in that, The ingredients include the following parts by weight: 10-12 parts metal catalyst, 8-10 parts synergist / accelerator, 5-8 parts metal salt, 10-12 parts organic acid, 1-2 parts dispersant, 10-20 parts persulfate; The synergist is prepared by the following method: S1: Hexadecyl dimethyl tertiary amine reacts with epichlorohydrin to form an epoxy quaternary ammonium salt compound. S2: Epoxy quaternary ammonium salt compounds react with 1,8-octanediamine to form bisquaternary ammonium salt compounds. S3: The reaction of bis-quaternary ammonium salt compounds with epichlorohydrin produces bis-tertiary amine bis-quaternary ammonium salt compounds. S4: The reaction of a bis-tertiary amine bis-quaternary ammonium salt compound with 4-pyridine carboxamide produces a synergistic promoter.
2. The flue gas desulfurization and denitrification enhancer according to claim 1, characterized in that, In step S1, the molar ratio of hexadecyl dimethyl tertiary amine to epichlorohydrin is 1:(1.1-1.2).
3. The flue gas desulfurization and denitrification enhancer according to claim 1, characterized in that, In step S2, the molar ratio of the epoxy quaternary ammonium salt compound to 1,8-octanediamine is (2.0-2.2):
1.
4. The flue gas desulfurization and denitrification enhancer according to claim 1, characterized in that, In step S3, the molar ratio of the bisquaternary ammonium salt compound to epichlorohydrin is 1:(2.05-2.2).
5. The flue gas desulfurization and denitrification enhancer according to claim 1, characterized in that, In step S4, the molar ratio of the bis-tertiary amine bis-quaternary ammonium salt compound to 4-pyridine carboxamide is 1:(2.1-2.3).
6. The flue gas desulfurization and denitrification enhancer according to claim 1, characterized in that, The metal catalyst is one of manganese sulfate and ferrous sulfate.
7. The flue gas desulfurization and denitrification enhancer according to claim 1, characterized in that, The metal salt is one of sodium acetate or sodium sulfate.
8. The flue gas desulfurization and denitrification enhancer according to claim 1, characterized in that, The organic acid is one of citric acid and adipic acid.
9. The flue gas desulfurization and denitrification enhancer according to claim 1, characterized in that, The dispersant is sodium polyacrylate; the persulfate is either sodium persulfate or ammonium persulfate.
10. A method for preparing the flue gas desulfurization and denitrification enhancer according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Weigh out the following by weight: 10-12 parts of metal catalyst, 8-10 parts of synergist, 5-8 parts of metal salt, 10-12 parts of organic acid, 1-2 parts of dispersant, and 10-20 parts of persulfate; (2) Mix the metal catalyst, synergist, metal salt, organic acid, dispersant and persulfate, stir and mix thoroughly, then grind in a planetary ball mill to obtain the flue gas desulfurization and denitrification synergist.