A method for preparing a nitric oxide absorbent for flue gas from a coal-fired power unit and its application.

Abstract

This invention relates to a method for preparing a nitric oxide absorbent for flue gas from a coal-fired power plant and its application, comprising the following steps: preparing tridentate aldehyde through a multi-step organic synthesis reaction; preparing triangular prism cage-like molecules; preparing a nitric oxide absorbent stock solution; and formulating the nitric oxide absorbent. The beneficial effects of this invention are: employing the principle of physical adsorption, the triangular prism cage-like compound captures NO through physical adsorption, and through desorption, high-purity nitric oxide gas can be obtained and reused for NO molecule absorption. This method is safer than traditional chemical methods, effectively avoiding the environmental hazards caused by ammonia escape and the impact of byproducts such as ammonium bisulfate on the normal operation of the unit, and also features high recycling rate and long service life.

Description

Technical Field

[0001] This invention belongs to the field of industrial hazardous waste treatment and environmental protection, and particularly relates to a method for preparing a nitric oxide absorbent in flue gas from a coal-fired power plant and its application. Background Technology

[0002] With rapid economic growth in China, coal consumption has increased significantly. NOx produced in the flue gas from coal-fired power plants is one of the major air pollutants, a key factor in photochemical smog and the greenhouse effect, seriously threatening the ecological environment. Currently, coal-fired power plants mainly use SCR technology, employing NH3 as a reducing agent. While NH3 primarily reacts with NO, escaped ammonia also reacts with SO3 and H2O in the flue gas to form ammonium bisulfate, which can clog air preheaters, electrostatic precipitators, or bag filters, affecting unit operation.

[0003] Patent CN108176193B discloses a nanofluid absorbent for wet denitrification of flue gas. The absorbent is composed of an absorbent base liquid consisting of Na2S2O8, NaCl, FeSO4, and water, with the addition of a dispersant stabilizer and inorganic nanoparticles. The absorption efficiency reaches more than 82.4% after using this nanofluid, which is 13.6% higher than that without the addition. However, the nanofluid is unstable, prone to agglomeration, and has poor recycling effect.

[0004] Patent CN110124497B discloses a desulfurization and denitrification absorbent and its uses, comprising 3-10% alkaline components and 3-8% antioxidants, with the remainder being water. After 30 minutes of circulation, the NOx removal rate is 98.7%, and after 4 hours of circulation, the NOx removal rate can still reach 83.3%. However, the antioxidant sodium thiosulfate has poor stability and is not easy to store. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a nitric oxide absorbent in the flue gas of a coal-fired unit and its application.

[0006] This nitrogen monoxide absorbent in the flue gas of a coal-fired unit includes a triangular prism cage-like compound, namely Triprism-C1 or Triprism-C2, whose molecular structural formulas are as follows:

[0007]

[0008] in

[0009] The preparation method of this nitric oxide absorbent in the flue gas of a coal-fired power unit includes the following steps:

[0010] Step 1: Preparation of trigonal cage-like molecules: Tridentate aldehyde is prepared through several organic synthesis reactions. The reaction of tridentate aldehyde and tridentate amine is carried out in CH2Cl2 or CHCl3 solvent at a reaction temperature of 298K to 303K. After filtering out the insoluble matter, the filtrate is dried and the solvent is finally evaporated to obtain a solid trigonal cage-like compound.

[0011] Step 2: Preparation of nitric oxide absorbent stock solution: Dissolve the triangular prism cage-like compound obtained in Step 1 in acetonitrile and mix it with water to form a milky white emulsion. Then, remove the acetonitrile by rotary evaporation to obtain the nitric oxide absorbent stock solution.

[0012] Step 3: Prepare the nitric oxide absorbent: Mix the nitric oxide absorbent stock solution with the demineralized water to form a slurry, and adjust the pH of the slurry to 10-12 to form the nitric oxide absorbent.

[0013] Preferably, in step one, the preparation method of tridentate aldehyde is as follows:

[0014] 2-Bromo-5-tert-butyl-1,3-xylene and elemental magnesium were dissolved in anhydrous tetrahydrofuran, followed by the addition of 5-bromofuran-2-carboxaldehyde. The mixture was quenched and extracted, the organic phases were combined and dried, and the solvent was removed by rotary evaporation to obtain compound S1. The reaction formula is as follows:

[0015]

[0016] S1 and 2-bromofuran were then dissolved in CH2Cl2, followed by the addition of boron trifluoride ether for quenching and extraction. The organic phases were combined, dried, and purified by rotary evaporation to obtain compound S2. The reaction formula is as follows:

[0017]

[0018] S2 was dissolved in anhydrous tetrahydrofuran, followed by the addition of isopropyl magnesium chloride. The reaction mixture was heated to room temperature, and piperidine-1-carboxaldehyde was added for quenching. Extraction followed by combining the organic phases and drying. The solvent was then removed by rotary evaporation, and the mixture was purified to give compound S3. The reaction formula is as follows:

[0019]

[0020] S3, planar triboronate M1, K2CO3, and Pd(PPh3)4 were dissolved in DMF, and the mixture was stirred. After cooling to room temperature, the solution was poured into deionized water, and the mixture was extracted. The combined organic phases were dried, the solvent was removed by rotary evaporation, and the solution was purified to obtain compound S4, which is tridentate aldehyde. The reaction formula is as follows:

[0021]

[0022] Preferably, in step one, the tridentate amine is either Tria-1 or Tria-2, and the molecular structural formulas of Tria-1 and Tria-2 are respectively...

[0023]

[0024] The reaction equations for the reaction of Tria-1 and Tria-2 with dentin in CHCl3 or CH2Cl2 solvents are as follows:

[0025]

[0026]

[0027] in,

[0028] As a preferred option, in step one, by... 1 HNMR spectra determine whether the reaction between the tridentate aldehyde and the tridentate amine is complete. Specifically, when... 1 When the characteristic peak of the aldehyde hydrogen disappears in the HNMR spectrum, and the characteristic peak of the Schiff base hydrogen appears and the integral of the characteristic peak of the Schiff base hydrogen with the characteristic peaks of other sites is proportional, it indicates that the reaction between the tridentate aldehyde and the tridentate amine is complete.

[0029] The application of this nitrogen monoxide absorbent in the flue gas of coal-fired power units, used for the physical adsorption of NO in the flue gas, specifically includes the following steps:

[0030] Step 1, NO capture: Pass a raw gas containing NO, CO2 and SO2 into the nitric oxide absorbent. The triangular prism cage-like compounds in the nitric oxide absorbent capture NO through physical adsorption.

[0031] Step 2: Separation of high concentration NO: The nitric oxide adsorbent after NO capture is subjected to solid-liquid phase separation to obtain an aqueous phase and a filter cake. The filter cake is desorbed by depressurization to separate NO from the triangular prism cage-like compound.

[0032] Step 3, Recycling: Stir the filter cake after NO separation with the aqueous phase obtained after solid-liquid phase separation to reform the nitric oxide adsorbent.

[0033] Preferably, the apparatus includes an absorption unit, a solid-liquid separation unit, a desorption unit, and a dissolution and mixing device. The nitric oxide absorbent captures NO in the absorption unit. After NO capture, the nitric oxide adsorbent undergoes solid-liquid separation in the solid-liquid separation unit to obtain an aqueous phase and a filter cake. The filter cake is desorbed under reduced pressure in the desorption unit to separate NO from the triangular prism cage-like compound. The aqueous phase obtained from the solid-liquid separation unit and the filter cake after reduced pressure desorption are processed by the dissolution and mixing device before being input into the absorption unit.

[0034] As a preferred method, the concentrations of each component in the feed gas before and after capture are measured, and then the NO absorption efficiency and NO absorption selectivity of the nitric oxide absorbent are evaluated. The specific calculation formula is as follows:

[0035]

[0036]

[0037] Among them, [NO] inlet and [NO] outlet [X] represents the NO concentration in the feed gas before and after capture, respectively. inlet and [X] outlet These represent the sum of the concentrations of waste gas X (excluding NO) in the raw gas before and after absorption, respectively. Specifically, waste gas X consists of CO2 and SO2.

[0038] The beneficial effects of this invention are:

[0039] 1) The nitric oxide absorbent provided by this invention has extremely strong selectivity for target NO molecules, and can improve the NO removal efficiency to over 99%. Furthermore, through analysis, high-purity nitric oxide gas can be obtained and reused for the absorption of NO molecules.

[0040] 2) The main components of the nitric oxide absorbent provided by the present invention are simple to synthesize and easy to prepare, have stable chemical composition, and are suitable for mass production and storage. The nitric oxide absorbent stock solution can be mixed with anhydrous salt water to form a nitric oxide absorbent slurry, and the nitric oxide absorbent stock solution is easy to store.

[0041] 3) The nitric oxide absorbent provided by this invention adopts the principle of physical adsorption. The triangular prism cage-like compound captures NO through physical adsorption, which is safer than traditional chemical methods. It effectively avoids the environmental hazards caused by ammonia escape and the impact of byproducts such as ammonium bisulfate on the normal operation of the unit. It also has a high recycling rate and a long service life. Attached Figure Description

[0042] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of compound S1;

[0043] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of compound S2;

[0044] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of compound S3;

[0045] Figure 4 This is the hydrogen nuclear magnetic resonance spectrum of compound S4;

[0046] Figure 5 This is the 1H NMR spectrum of the compound Triprism-C1;

[0047] Figure 6 This is the high-resolution mass spectrum of compound Triprism-C1;

[0048] Figure 7 This is a flowchart of the working cycle and reuse of the absorbent;

[0049] Figure 8 This is a schematic diagram of the working cycle and reuse process of the absorbent;

[0050] Figure 9 This is a diagram showing the effect of NO removal;

[0051] Figure 10 This is a graph showing the NO removal effect after long-term operation. Detailed Implementation

[0052] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make several modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0053] Example 1

[0054] Step 1: Preparation of triangular prism-shaped cage molecules: Tridentate aldehydes were prepared through several organic synthesis reactions.

[0055] 2-Bromo-5-tert-butyl-1,3-xylene and elemental magnesium were dissolved in anhydrous tetrahydrofuran, followed by the addition of 5-bromofuran-2-carboxaldehyde. The mixture was quenched and extracted, the organic phases were combined and dried, and the solvent was removed by rotary evaporation to obtain compound S1. The reaction formula is as follows:

[0056]

[0057] S1 and 2-bromofuran were then dissolved in CH2Cl2, followed by the addition of boron trifluoride ether for quenching and extraction. The organic phases were combined, dried, and purified by rotary evaporation to obtain compound S2. The reaction formula is as follows:

[0058]

[0059] S2 was dissolved in anhydrous tetrahydrofuran, followed by the addition of isopropyl magnesium chloride. The reaction mixture was heated to room temperature, and piperidine-1-carboxaldehyde was added for quenching. Extraction followed by combining the organic phases and drying. The solvent was then removed by rotary evaporation, and the mixture was purified to give compound S3. The reaction formula is as follows:

[0060]

[0061] S3, planar triboronate M1, K2CO3, and Pd(PPh3)4 were dissolved in DMF, and the mixture was stirred. After cooling to room temperature, the solution was poured into deionized water, and the mixture was extracted. The combined organic phases were dried, the solvent was removed by rotary evaporation, and the solution was purified to obtain compound S4, which is tridentate aldehyde. The reaction formula is as follows:

[0062]

[0063] The reaction of tridentate aldehyde and tridentate amine is carried out in CH2Cl2 or CHCl3 solvent at a reaction temperature of 298K to 303K. After filtering out the insoluble matter, the mixture is dried to obtain a solid triangular cage-like compound.

[0064] The tridentate amines mentioned are Tria-1 or Tria-2, and the molecular structural formulas of Tria-1 and Tria-2 are respectively...

[0065]

[0066] Tria-1 and Tria-2 react with tridentate aldehyde in CHCl3 or CH2Cl2 solvent, with the molar ratio of tridentate aldehyde to tridentate amine controlled between 1:1.1 and 1:1.3. The concentrations of both reactants are controlled at 10⁻⁶ throughout the reaction. -3 ~10 -5 The reaction temperature was 298 K to 303 K. After slow stirring for 4 h, the insoluble matter was filtered off, and the organic phase was dried. Subsequently, the solvent was removed by rotary evaporation to obtain triangular prism-shaped cage-like molecules.

[0067] The reaction equations for the reaction of Tria-1 and Tria-2 with dentin in CHCl3 or CH2Cl2 solvents are as follows:

[0068]

[0069] in,

[0070] Further steps can be taken 1 HNMR spectra can be used to determine whether the reaction is complete. The characteristic peak of the aldehyde hydrogen at around 10 ppm disappears, while the characteristic peak of the Schiff base hydrogen at around 8-9 ppm appears and is proportional to the characteristic peaks of other sites. High-resolution mass spectrometry can also be used to determine the formation of the product.

[0071] Step 2: Weigh the synthesized and dried cage-like compound solid and disperse it in acetonitrile. Sonicate until completely dissolved. Then pour the solution into a round-bottom flask containing a certain amount of water and continue to sonicate for 5-10 minutes until the mixture becomes a uniformly distributed milky white emulsion. Then evaporate the acetonitrile solvent to obtain the nitric oxide absorbent stock solution.

[0072] Step 3: Prepare the nitric oxide absorbent: Mix the nitric oxide absorbent stock solution with the demineralized water to form a slurry, and adjust the pH of the slurry to 10-12 to form the nitric oxide absorbent.

[0073] Example 2

[0074] As another embodiment, the nitrogen monoxide absorbent prepared in the flue gas of a coal-fired power unit is a supramolecular adsorbent. The concept of supramolecular chemistry was first proposed by the French chemist Professor Jean-Marie Lehn, who defined it as "chemistry beyond molecules," that is, chemistry based on weak interactions, studying ordered and complex systems composed of multiple molecules through intermolecular interactions. A supramolecular refers to a molecular group assembled by non-chemical bonds between molecules; these bonds are called supramolecular forces, which are weaker than traditional chemical bonds. The construction and application of a supramolecular system is often the result of the coordinated action of multiple supramolecular forces. Because these forces are relatively weak, they often exhibit better reversibility, and compared to covalent bonds, they have milder reaction conditions and stronger reversibility, making them suitable for industrial applications.

[0075] The main component of this nitric oxide absorbent is a triangular prism cage-like compound, namely Triprism-C1 or Triprism-C2. The molecular structural formulas of Triprism-C1 and Triprism-C2 are as follows:

[0076]

[0077] in

[0078] By introducing the furan structure into the molecule, furan, a heterocyclic structure with a strong electron-donating effect, and the resonance theory study of furan, it was found that the electron cloud density on the furan ring is large and has a significant tendency to combine with free radicals on the nitric oxide molecule. By introducing the furan ring into a topological molecule with a cavity, the triangular prism cage-like compound can selectively adsorb nitric oxide in the mixed gas.

[0079] The triangular prism cage-like compound involved in this invention can be used to separate nitric oxide from the flue gas emitted by coal-fired power units. The triangular prism cage-like compound can selectively bind nitric oxide for three reasons: First, a single molecule contains six furan structures, and the oxygen atom on each furan ring carries an electron-donating lone pair of electrons, which strongly attracts the electron-withdrawing free radical lone electrons on the nitrogen atom in NO. Second, the tetrabenzene ring planar structure of tridentate aldehydes and the triazine or tetrabenzene structure of tridentate amines together provide the upper and lower rigid planes of the cage-like molecule, avoiding spatial narrowing caused by structural distortion, and exhibiting a good synergistic effect with the furan structure, improving adsorption capacity and efficiency. Third, in slurry conditions, it provides a hydrophobic environment for the internal cavity of the triangular prism cage-like compound, ensuring the hollowness of the cavity and providing space for NO adsorption.

[0080] Example 3

[0081] As one embodiment, a specific embodiment of the method for preparing a nitric oxide absorbent in the flue gas of a coal-fired unit proposed in Embodiment 1 includes the following steps:

[0082] Step 1: Preparation of triangular prism-shaped cage molecules: First, tridentate aldehydes are prepared through several organic synthesis reactions, specifically,

[0083] Preparation of compound S1: 14.2 g (58.9 mmol) of 2-bromo-5-tert-butyl-1,3-xylene and 1.5 g (61.8 mmol) of elemental magnesium were dissolved in 60 mL of anhydrous THF. The solution was heated to reflux and stirred under nitrogen protection. Heating was stopped after the magnesium had almost disappeared, and the solution was cooled to room temperature. 12.23 g (65 mmol) of 5-bromofuran-2-carboxaldehyde was added in portions to the flask under ice bath conditions. After stirring for about 1 h, an aqueous solution was gradually added to quench the remaining Grignard reagent. The mixture was extracted three times with 100 mL of CH2Cl2, and the organic phases were combined and dried over anhydrous Na2SO4. The solvent was then removed by rotary evaporation, followed by purification by column chromatography with an EA / PE ratio of 1:5. The purified product was 14.62 g of compound S1 with a purity of 74%. The specific reaction formula is as follows:

[0084]

[0085] The proton NMR spectrum of compound S1 is shown below. Figure 1 As shown, 1 HNMR (400MHz, DMSO-d6): δ=8.89 (d, J=4.2Hz, 1H), 8.82 (d, J=4.2Hz, 1H), 7.21 (s, 2H), 3.32 (s, 1H), 2.43 (s, 6H), 1.55 (s, 9H).

[0086] Preparation of compound S2: 5 g (14.8 mmol) of S1 and 2.64 g (16.2 mmol) of 2-bromofuran were dissolved in 70 mL of CH2Cl2 under nitrogen purging for 30 min. Then, 2.11 g (1.43 mmol) of boron trifluoride ether (BF3·OEt2) was added to a flask under nitrogen protection and an ice bath. The mixture was stirred at room temperature for 4 h, and then a saturated ammonium chloride (NH4Cl) aqueous solution was slowly added to quench the reaction. The mixture was extracted three times with 60 mL of hexane, and the organic phases were combined and dried over anhydrous Na2SO4. The solvent was then removed by rotary evaporation, followed by purification by column chromatography with EA / PE = 1:4. 5.22 g of compound S2 with a purity of 76% was obtained. The specific reaction formula is as follows:

[0087]

[0088] The proton NMR spectrum of compound S2 is shown below. Figure 2 As shown, 1 HNMR (400MHz, DMSO-d6): δ=7.48 (d, J=3.6Hz, 2H), 7.47 (d, J=3.6Hz, 2H), 7.27 (s, 2H), 3.31 (s, 1H), 2.45 (s, 6H), 1.56 (s, 9H).

[0089] Preparation of compound S3: 3 g (5.9 mmol) of S2 was dissolved in 40 mL of anhydrous tetrahydrofuran (THF) and nitrogen gas was purged for 30 min. Then, 3.2 mL (6.4 mmol) of isopropyl magnesium chloride (iPrMgCl, 1.0 M THF solution) was added at -40 °C. After stirring for 0.5 h, the reaction mixture was heated to room temperature, and 0.81 g (6.9 mmol) of piperidine-1-carboxaldehyde was added. Stirring continued for 1 h. Then, a saturated ammonium chloride (NH4Cl) aqueous solution was slowly added to quench the reaction. The mixture was extracted three times with 30 mL of CH2Cl2, and the combined organic phases were dried over anhydrous Na2SO4. The solvent was then removed by rotary evaporation, followed by purification by column chromatography with CH2Cl2 / PE = 1:1. 1.62 g of compound S3 with a purity of 52% was obtained. The specific reaction formula is as follows:

[0090]

[0091] The proton NMR spectrum of compound S3 is shown below. Figure 3 As shown, 1HNMR (400MHz, DMSO-d6): δ=10.03 (s, 1H), 8.83 (d, J=1.2Hz, 1H), 8.69 (d, J=1.2Hz, 1H) , 8.29 (d, J=2.4Hz, 1H), 8.26 (d, J=2.4Hz, 1H), 7.88 (s, 2H), 2.43 (s, 6H), 1.54 (s, 9H).

[0092] Preparation of compound S4: 1.2 g, 2.9 mmol of S3, 0.62 g, 0.8 mmol of commercially available planar triborate ester M1, 2.25 g, 18.5 mmol of K2CO3, and 220 mg of Pd(PPh3)4 were weighed and dissolved in 30 mL of DMF. The solution was placed in a 100 mL round-bottom flask, and the system was sealed after purging with nitrogen for 30 minutes. The mixture was then stirred vigorously at 373 K for 24 h. After cooling to room temperature, the solution was poured into 250 mL of deionized water. The mixture was extracted three times with 30 mL of CH2Cl2. The combined organic phases were dried over anhydrous Na2SO4. The solvent was then removed by rotary evaporation, followed by purification by column chromatography with an EA / PE ratio of 2:1. 0.33 g of compound S4 with a purity of 31% was obtained. The specific reaction formula is as follows:

[0093]

[0094] Compound S4 is tridentate aldehyde.

[0095] The proton NMR spectrum of compound S4 is shown below. Figure 4 As shown, 1 HNMR (400MHz, DMSO-d6): δ = 9.93 (s, 3H), 8.79 (d, J = 3.6Hz, 3H), 8.22 (d, J = 3.6Hz, 3H), 7.87 (d , J=2.4Hz, 3H), 7.83 (d, J=2.4Hz, 3H), 7.11 (s, 3H), 5.85 (s, 3H), 2.45 (s, 18H), 1.54 (s, 27H).

[0096] In this embodiment, the triangular prism cage compound is Triprism-C1.

[0097] 200 mg (0.143 mmol) of S4 was dissolved in 15 mL of CH2Cl2, and 53.83 mg (0.152 mmol) of commercially available triazine triphenylamine (Tria-1) was dissolved in 15 mL of CH2Cl2. After both solutions were clarified, they were mixed at a 1:1 volume ratio and heated in a water bath at 303 K for 4 h. The insoluble matter was filtered off, and the organic phase was dried over anhydrous Na2SO4. The solvent was then removed by rotary evaporation to obtain 223 mg of Triprism-C1 with a purity of 88%.

[0098] The proton NMR spectrum of Triprism-C1 is shown below. Figure 5 As shown, 1 HNMR (400MHz, DMSO-d6): δ=8.51 (d, J=2.4Hz, 3H), 7.96 (d, J=3.2Hz, 3H), 7.89 (d, J =3.6Hz, 3H), 7.84 (d, J = 1.8Hz, 3H), 7.75 (d, J = 2.4Hz, 3H), 7.66 (d, J = 6.4Hz, 3H), 7 .62 (d, J=3.6Hz, 3H), 7.58 (d, J=1.2Hz, 3H), 7.52 (s, 3H), 7.47 (d, J=7.6Hz, 3H), 7. 25 (d, J=7.6Hz, 3H), 7.18 (d, J=6.4Hz, 3H), 5.89 (s, 3H), 2.41 (s, 18H), 1.52 (s, 27H).

[0099] The successful synthesis was further confirmed by ion trap time-of-flight mass spectrometry (LCMS-IT-TOF), and the high-resolution mass spectrum of Triprism-C1 is shown below. Figure 6 As shown.

[0100] Step 2: Preparation of nitric oxide absorbent stock solution: Weigh 500 mg of the synthesized and dried Triprism-C1 solid and disperse it in 5 ml of acetonitrile. Sonicate until completely dissolved. Then pour the Triprism-C1 acetonitrile solution into a round-bottom flask containing 20 ml of water and continue to sonicate for 5 min until the mixture becomes a uniformly distributed milky white emulsion. Then evaporate the acetonitrile solvent for later use.

[0101] Step 3: Prepare the nitric oxide absorbent: Mix the nitric oxide absorbent stock solution and demineralized water at a mass ratio of 1:10. Adjust the pH of the slurry to 10-12 with sodium hydroxide solution to form the nitric oxide absorbent.

[0102] Example 4

[0103] As another embodiment, the application of the nitric oxide absorbent prepared in Example 3 for flue gas treatment in coal-fired power plants was investigated. To verify the effectiveness of the invention, an experimental platform was built next to the flue gas duct of a coal-fired power plant in southern China, and a bypass flue was installed. Experiments on the treatment of exhaust gas were conducted. Figure 7As shown, a pilot-scale experimental platform for nitric oxide absorbent is constructed. The main structure of the platform consists of an absorption unit, a solid-liquid separation unit, a desorption unit, and a dissolution and mixing device. Nitric oxide absorbent captures NO in the absorption unit. After NO capture, the nitric oxide absorbent undergoes solid-liquid separation in the solid-liquid separation unit to obtain an aqueous phase and a filter cake. The filter cake is then desorbed under reduced pressure in the desorption unit to separate high-purity NO from the triangular prism-shaped cage-like compound. The aqueous phase and the desorbed filter cake obtained from the solid-liquid separation unit are processed by the dissolution and mixing device before being input into the absorption unit.

[0104] The composition of the feed gas for the simulated coal-fired power unit flue gas is: 400ppm NO, 2000ppm SO2, with CO2 accounting for 12% / 8% / 4% / 1% / 0.1%, and the remainder being N2.

[0105] The operation process of the pilot-scale experimental platform is as follows: After the raw gas is pressure regulated and stabilized, the flow rate is controlled by a mass flow meter or a float flow meter. It is heated to a certain temperature by a preheater and then enters the absorption unit. Adsorbent is added to the absorption unit. The raw gas is fully mixed with the adsorbent by bubbling or a gas distributor in the absorption unit. The triangular prism cage-like compounds in the nitric oxide absorbent capture NO through physical adsorption. The remaining gas after capture is discharged from the top of the tower or sent to the flue gas analyzer.

[0106] The collected adsorbent slurry is pumped to the solid-liquid separation unit at a certain flow rate by a plunger metering pump. Solid-liquid phase separation is achieved through filtration. The filter cake is then desorbed under reduced pressure to separate the high concentration of NO from the triangular prism-shaped cage-like compound. The desorbed filter cake is then stirred and mixed with the aqueous phase to reform the nitric oxide adsorbent, which is then pumped into the absorption unit for reuse. Figure 8 As shown.

[0107] This pilot-scale platform was used to evaluate the performance of the absorbent. The specific calculation formula is as follows:

[0108]

[0109]

[0110] Among them, [NO] inlet and [NO] outlet [X] represents the NO concentration in the feed gas before and after capture, respectively. inlet and [X] outlet These represent the sum of the concentrations of waste gas X (excluding NO) in the raw material gas before and after absorption, respectively. Specifically, waste gas X consists of CO2 and SO2.

[0111] The absorption rate curves of the absorbent at different times with a CO2 content of 12% were tested, as shown below. Figure 9 As shown.

[0112] The final absorption test data are shown in the table below. The results show that the absorbent absorbs NO very quickly, reaching more than 90% in ten minutes.

[0113] <![CDATA[CO2 volume fraction]]> NO final content (ppm) Selective 12％ 1.82 99.0 8％ 1.76 99.3 4％ 1.43 99.6 1％ 1.22 99.8 0.1％ 0.99 99.8

[0114] After passing through the absorbent of this invention, the NO content is reduced to below 2 ppm under different carbon dioxide partial pressure conditions, and the absorption selectivity is above 99%, indicating that the absorbent has a wide range of operating conditions and can reduce the NO concentration in the flue gas of coal-fired units to a low level.

[0115] Example 5

[0116] As another embodiment, the application of the nitric oxide absorbent prepared in Example 2 in the flue gas of a coal-fired unit was carried out using the same pilot-scale experimental platform for the nitric oxide absorbent as in Example 4. The composition of the flue gas of the simulated coal-fired unit was: 12% CO2, 1500ppm SO2, NO content of 300 / 200 / 100 / 50ppm, and the remainder being N2.

[0117] The final absorption test data are shown in the table below:

[0118] NO percentage (ppm) NO final content (ppm) Selective 300 1.29 99.1 200 1.15 99.2 100 1.03 99.3 50 0.87 99.5

[0119] After passing through the absorbent of this invention, the NO content is reduced to below 2 ppm. Under different NO concentration conditions, the absorption selectivity is above 99%, indicating that the absorbent has a wide range of operating conditions and can reduce the NO concentration in the flue gas of coal-fired units to a low level.

[0120] Example 6

[0121] As another embodiment, the application of the nitric oxide absorbent prepared in Example 2 for flue gas from a coal-fired power plant was carried out using the same pilot-scale experimental platform as in Examples 4 and 5. The simulated flue gas composition of the coal-fired power plant was: 12% CO2, 2000 ppm SO2, 300 ppm NO, and the remainder N2. The absorption efficiency and selectivity of nitric oxide under long-term operating conditions were tested as follows: Figure 10 As shown, the graph of nitric oxide absorption efficiency is represented by a square, and the graph of nitric oxide selectivity is represented by a circle.

[0122] Experimental results show that the absorption efficiency and selectivity of the absorbent for nitric oxide did not change significantly during long-term operation, indicating that the absorbent has high stability and still has extremely high nitric oxide absorption capacity after repeated use.

Claims

1. A nitrogen monoxide absorbent in flue gas of a coal-fired unit, characterized by: The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is wherein 2. A process for the preparation of a nitrogen monoxide absorbent in the flue gas of a coal-fired power plant as claimed in claim 1, characterized in that, The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is 3. The method of claim 2, wherein the NOx absorbent is prepared by the steps of: The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is 4. The method of claim 3, wherein the NOx absorbent is prepared by the steps of: The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is wherein 5. The method of claim 4, wherein the NOx absorbent is prepared by the steps of: In step one, whether the tridentate aldehyde and the tridentate amine are completely reacted is determined by 1 HNMR spectrum. Specifically, when the characteristic peak of aldehyde hydrogen disappears in the HNMR spectrum, the characteristic peak of the Schiff base hydrogen appears, and the characteristic peak of the Schiff base hydrogen is proportional to the characteristic peak of other sites, it is indicated that the tridentate aldehyde and the tridentate amine are completely reacted. 1 ​ 6. Use of a nitrogen monoxide absorbent in flue gas of a coal-fired power plant according to claim 1, characterized in that, The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of trident prism cage compounds, and the trident prism cage compound is Triprism-C1, and the molecular structural formula of Triprism-C1 is The application relates to a kind of tr 7. Use of a NOx absorbent in flue gases of a coal-fired power plant according to claim 6, characterized in that, The absorption unit, the solid-liquid separation unit, the desorption unit and the dissolving and mixing device are provided, the nitrogen monoxide absorbent captures NO in the absorption unit, the nitrogen monoxide absorbent after capturing NO is subjected to solid-liquid separation in the solid-liquid separation unit to obtain an aqueous phase and a filter cake, the filter cake is subjected to decompression desorption in the desorption unit to separate NO from the triangular prism cage compound, and the aqueous phase obtained by the solid-liquid separation unit and the filter cake after decompression desorption are treated by the dissolving and mixing device and then input into the absorption unit.

8. Use of a NOx absorbent in flue gases of a coal-fired power plant according to claim 6, characterized in that, The concentrations of each component in the raw material gas before and after capturing are measured, and then the NO absorption efficiency and NO absorption selectivity of the nitrogen monoxide absorbent are evaluated, and the specific calculation formula is as follows: wherein [NO] inlet and [NO] outlet respectively indicate the concentration of NO in the raw material gas before and after the capture, [X] inlet and [X] outlet respectively indicate the sum of the concentration of the exhaust gas X other than NO in the raw material gas before and after the absorption, the exhaust gas X being specifically CO2 and SO2.

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