Boiler ash and coke removing agent, its preparation method and application

Abstract

The application discloses a boiler ash and coking removing agent, a preparation method and application thereof, and belongs to the technical field of coking removing agents. The application is used for solving the technical problems of slow coking removing effect of solid coking removing agents and poor coking removing effect of liquid coking removing agents in the prior art. The boiler ash and coking removing agent comprises aluminum nitrate, potassium nitrate, magnesium nitrate, composite catalyst microspheres, mixed organic acid and water. A multi-amino polyphenyl polycondensate solution and toluene diisocyanate are reacted to obtain a supramolecular polymer solution; sodium hydroxide, dodecyl dimethyl betaine, paraffin wax, copper oxide and iron oxide are uniformly mixed to obtain a mixture; and the composite catalyst microspheres are prepared by coating the mixture with the supramolecular polymer solution; and the composite catalyst microspheres can realize fixed-point blasting under high-temperature conditions. The prepared boiler ash and coking removing agent is sprayed into a boiler in a atomizing mode for coking removing, and has the advantages of rapid coking removing reaction and good coking removing effect.

Description

Technical Field

[0001] This invention relates to the field of descaling agents, specifically to a boiler ash removal and descaling agent, its preparation method, and its application. Background Technology

[0002] Boilers experience significant coking during long-term operation. Coking poses numerous health risks, including: 1. Increased temperatures in the superheater and reheater. Increased superheater and reheater desuperheating water flow can lead to tube overheating, forced load reduction, or excessive stress causing tube rupture. 2. Coking on water-cooled walls and horizontal flues reduces heat transfer coefficients. Maintaining boiler evaporation requires increased fuel consumption, leading to higher coal costs; increased flue gas temperatures in vertical flues, particularly at the denitrification inlet, negatively impact catalyst efficiency and lifespan. 3. Damage to water-cooled wall tubes in the cold ash hopper. Severe coking forming large coke lumps can cause them to detach due to disturbance and gravity; wet ash removal systems face the significant risk of coke lumps causing steam to rise, leading to unstable combustion or even flameout. Current technologies often employ boiler decoking agents to remove coking and prevent new coking.

[0003] Common types of descaling agents include liquid and solid descaling agents. Patent application CN105670733A discloses a synergistic denitrification type liquid boiler descaling agent and its preparation method. The components of the descaling agent include magnesium acetate, copper nitrate, nickel nitrate, ammonium nitrate, boric acid, cerium nitrate, and water. When using liquid descaling agents, simply use compressed air to spray the liquid from the dosing tank through the observation hole in the furnace; the operation is simple and convenient. Liquid descaling agents have the advantage of rapid descaling effect. Furthermore, liquid descaling agents can quickly dissolve and adsorb onto the coke layer through atomization and high-temperature vaporization, exhibiting rapid descaling performance. However, compared to solid descaling agents with explosive effects, liquid descaling agents have the disadvantage of poor descaling effect.

[0004] Patent application CN102337169A discloses a multi-element slag removal and ash cleaning energy-saving agent composition for boilers and its preparation process. This slag removal composition contains manganese carbonate, manganese sulfate, potassium permanganate, copper oxide, etc. The composition is added evenly to the coal conveyor belt or coal scraper using a feeder. This prior art uses copper, manganese, zinc, and molybdenum to transform the existing heterogeneous glassy slag structure into a crystalline slag structure, promoting the development of dense, hard coke into a porous, lightweight, brittle, and easily broken aggregate, thereby reducing the hardness of the coke slag. However, this solid slag removal agent suffers from technical problems such as purely chemical slag removal and slow slag removal efficiency.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a boiler ash removal and slag removal agent, its preparation method and application, to solve the technical problems of slow slag removal effect of solid slag removal agents and poor slag removal effect of liquid slag removal agents in the prior art.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A boiler ash removal and slag removal agent, comprising, by weight: 2-5 parts aluminum nitrate, 3-5 parts potassium nitrate, 5-10 parts magnesium nitrate, 3-10 parts composite catalyst microspheres, 3-10 parts mixed organic acid and 60-84 parts water.

[0009] The composite catalyst microspheres are obtained by modifying a supramolecular polymer solution with a mixture of sodium hydroxide, dodecyl dimethyl betaine, paraffin, copper oxide, and iron oxide as the core composite material. The supramolecular polymer solution is obtained by reacting a polyamino-polyphenyl condensate solution with toluene diisocyanate. The polyamino-polyphenyl condensate solution is obtained by dissolving the polyamino-polyphenyl condensate in tetrahydrofuran. The polyamino-polyphenyl condensate is obtained by reacting potassium phenolate, hexachlorocyclotriphosphazene, triethylamine, and chlorobenzene.

[0010] The mixed organic acid is obtained by mixing boric acid, phytic acid and choline chloride.

[0011] The boiler ash removal and char removal agent prepared by this invention is a solid-liquid mixture containing a small amount of composite catalyst microspheres.

[0012] The method for preparing the composite catalyst microspheres includes the following steps:

[0013] A1. Potassium phenolate, hexachlorocyclotriphosphazene, triethylamine and chlorobenzene are mixed to obtain a reaction system; the reaction system is reacted at 80-90℃ for 6-8 hours to obtain the reactants;

[0014] Using triethylamine as a catalyst and chlorobenzene as a solvent, potassium phenolate and hexachlorocyclotriphosphazene undergo a nucleophilic substitution reaction to yield the reactants. The reaction equation is as follows:

[0015]

[0016] A2. The reactants are allowed to cool naturally to room temperature, and then cooled to -5~5℃. The reactants are kept in an ammonia atmosphere and reacted at a constant temperature for 12-24 hours to obtain an intermediate. The intermediate is polycondensed at 150-200℃ for 20-30 minutes to obtain a solid polyamino-polyphenyl condensate.

[0017] Ammonia gas is introduced into the reactants, and under the action of triethylamine, a strong organic base, the reactants react with ammonia gas through an elimination-addition reaction to obtain an intermediate; the intermediate is further polycondensed to prepare a polyamino-polyphenyl condensate.

[0018] The reaction formula for preparing polyamino-phenylene condensates by reacting the reactants with ammonia is as follows:

[0019]

[0020]

[0021] A3. The polyamino-polyphenyl condensate is dissolved in tetrahydrofuran to obtain a polyamino-polyphenyl condensate solution; toluene diisocyanate is added to the above polyamino-polyphenyl condensate solution, ultrasonically dispersed, and then reacted at room temperature to obtain a reaction solution; the reaction solution is concentrated to 50-60% of its original volume to obtain a supramolecular polymer solution.

[0022] A solution of polyamino-polyphenylene condensate undergoes a nucleophilic addition reaction with toluene diisocyanate to yield a supramolecular polymer solution. The polymer solution is then concentrated to increase the polymer content, thus preparing another supramolecular polymer solution. The reaction formula is as follows:

[0023]

[0024] A4, sodium hydroxide, dodecyl dimethyl betaine, paraffin, copper oxide and iron oxide are mixed to obtain a mixture; the mixture is ball-milled to obtain a core composite material with a mesh size of 200-300; the core composite material and supramolecular polymer solution are added to a continuous powder surface modifier at a mass ratio of 1-5:100 to obtain composite catalyst microspheres.

[0025] The prepared supramolecular polymer solution was used as a surface modifier to modify and coat the core composite material, thereby preparing composite catalyst microspheres.

[0026] Further, in step A1, the ratio of potassium phenolate, hexachlorocyclotriphosphazene, triethylamine, and chlorobenzene is 2.64-5.28 g: 3.46-6.92 g: 3-5 g: 50-100 mL; in step A3, the ratio of polyaminopolyphenylene condensate, tetrahydrofuran, and toluene diisocyanate is 15-20 g: 50-60 mL: 3.48-6.96 g; the ultrasonic dispersion frequency is 20-30 kHz, the ultrasonic dispersion time is 5-10 min, and the reaction time at room temperature is 24 h.

[0027] Further, in step A4, the weight ratio of sodium hydroxide, dodecyl dimethyl betaine, paraffin, copper oxide, and iron oxide is 5-10:5-10:10-20:0.1-1:0.1-1; the rotation speed of the continuous powder surface modification machine is 2000-3000 r / min, the modification temperature is 65-75℃, and the modification time is 5-10 min.

[0028] Furthermore, the mixed organic acid is prepared by the following steps:

[0029] Boric acid and phytic acid are mixed in a mass ratio of 1:1 to obtain organic acids; choline chloride and organic acids are mixed in a mass ratio of 1:2-5 to obtain mixed organic acids.

[0030] As another aspect of the present invention, a method for preparing a boiler ash removal and slag removal agent includes the following steps:

[0031] Aluminum nitrate, potassium nitrate, magnesium nitrate, composite catalyst microspheres, mixed organic acid, and water are mixed to obtain a boiler ash removal and coking agent.

[0032] As another aspect of the present invention, the application of a boiler ash removal and slag removal agent includes the following steps:

[0033] Boiler ash removal and slag removal agent is added to the addition tank, and then atomized under pressure to obtain atomized boiler ash removal and slag removal agent; the atomized boiler ash removal and slag removal agent is then sprayed into the boiler through a nozzle.

[0034] Furthermore, the pressurization pressure is 0.4-0.7 MPa, and the dosage of the boiler ash remover and slag remover is 1-2‰ of the coal mass. This invention uses pressurized atomization to spray the boiler ash remover and slag remover into the boiler.

[0035] The present invention has the following beneficial effects:

[0036] 1. The boiler ash removal and descaling agent prepared by this invention comprises metal nitrates (aluminum nitrate, potassium nitrate, and magnesium nitrate), composite catalyst microspheres, mixed organic acids, and water. The metal nitrates act as strong oxidants and combustion aids. Boric acid and phytic acid are mixed to form an organic acid; boric acid can combine with carbon atoms around the crystal lattice and block diffusion channels in the absence of water vapor, helping to reduce the reactivity of coke; phytic acid has a chelating effect on heavy metals in boiler coke. Further blending choline chloride with the organic acid yields a mixed organic acid that can serve as a eutectic solvent, significantly improving the solubility of the mixed organic acid in deionized water.

[0037] 2. This invention uses a mixture of sodium hydroxide, dodecyl dimethyl betaine, paraffin wax, copper oxide powder, and iron oxide powder as the core composite material. Sodium hydroxide is strongly alkaline and can react with organic acids in coke; in addition, sodium hydroxide can also convert coke into soluble salts, thereby achieving the purpose of removing coke from the boiler. However, due to the strong corrosiveness and alkalinity of sodium hydroxide, to avoid corrosion of the metal walls in the high-temperature and low-temperature zones of the boiler, sodium hydroxide is used as the core of the composite catalyst to achieve targeted explosion and avoid corrosion. Both copper oxide and iron oxide have good sulfur-fixing effects. Furthermore, both copper oxide and iron oxide can act as catalysts, which can help change the crystal structure of coke and thus improve its combustion performance, thereby achieving a more efficient coke removal effect. Dodecyl dimethyl betaine, which has a foaming effect, and paraffin wax, which can be vaporized at low temperatures, are added to the core material. Under the high temperature of the boiler, the prepared composite catalyst microspheres undergo targeted explosion through foaming and vaporization, causing the coke to become loose, thereby enhancing the coke removal effect.

[0038] 3. To improve the impact resistance of the prepared composite catalyst microspheres on the coke block and the protective force on the core composite material, this invention uses potassium phenolate-modified hexachlorocyclotriphosphazene as a reactant. The reactant is amination followed by polycondensation to prepare a polyamino-polyphenyl condensate with multiple benzene rings and high molecular weight. Toluene diisocyanate is then added to the above condensate to eliminate active groups, reduce reactivity, and further increase the amount of benzene rings and molecular weight, thereby preparing a membrane material with high mechanical properties, improving the protective force and expansion load capacity of the core composite material.

[0039] 4. The boiler ash removal and slag removal agent synthesized in this invention can be sprayed into the boiler via atomization. Some components of the agent can rapidly vaporize at high temperatures, penetrating the entire boiler's heating surfaces with the high-temperature flue gas. They quickly dissolve and adsorb onto the coke layer, rapidly penetrating deep into the coke layer to initiate a chemical reaction, altering the hard crystal lattice within the coke layer, causing it to loosen, crack, detach, and burn. This reduces the thermal resistance of the heating surfaces and improves the boiler's heat transfer efficiency. Furthermore, the composite catalyst microspheres possess high expansion and bursting capabilities at high temperatures, impacting the boiler coke lumps through their own impact force. The boiler ash removal and slag removal agent prepared in this invention has the advantages of high slag removal efficiency (the dosage of the boiler ash removal and slag removal agent is 1-2‰ of the coal mass) and good slag removal effect (significant reduction in the inlet flue gas temperature of the reheater, the inlet flue gas temperature of the low-temperature superheater, and the desuperheating water volume). Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] This embodiment provides a method for preparing composite catalyst microspheres for boiler ash removal and char removal agents, including the following steps:

[0043] A1. Add 2.64 g of potassium phenolate, 3.46 g of hexachlorocyclotriphosphazene, 3 g of triethylamine, and 50 mL of chlorobenzene to a 250 mL three-necked flask equipped with a thermometer, stirrer, and reflux condenser. Mix to obtain the reaction system. Transfer the three-necked flask to an oil bath and heat to 80 °C. React at this temperature for 6 hours to obtain the reactants.

[0044] A2. The reactants were allowed to cool naturally to room temperature. The three-necked flask was then transferred to a low-temperature water bath at -5°C. Ammonia gas was continuously introduced into the three-necked flask, and the reaction was carried out at this temperature for 12 hours to obtain an intermediate. The intermediate was placed in a drying oven and polycondensed at 150°C for 20 minutes. Afterward, it was removed to obtain a solid, which is the prepared polyamino-polyphenyl condensate.

[0045] A3. Add 15g of the polyamino-phenylene condensate and 50mL of tetrahydrofuran to a 250mL short-necked round-bottom flask, stir to dissolve, and obtain a polyamino-phenylene condensate solution. Add 3.48g of toluene diisocyanate to the above polyamino-phenylene condensate solution, and disperse by ultrasonication at a frequency of 20kHz for 5min. Then stir at room temperature for 24h to obtain a reaction solution. Concentrate the reaction solution to 50% of its original volume to obtain a supramolecular polymer solution.

[0046] A4. According to weight, 5 parts of sodium hydroxide, 5 parts of dodecyl dimethyl betaine, 10 parts of paraffin wax, 0.1 parts of copper oxide powder, and 0.1 parts of iron oxide powder are mixed to obtain a mixture. The mixture is then ball-milled to obtain a 200-mesh core composite material. The core composite material and supramolecular polymer solution are added to a continuous powder surface modifier at a mass ratio of 1:100 for modification. The rotor speed is 2000 r / min, the temperature of the modifier is 65℃, and the modification time is 5 min to obtain composite catalyst microspheres.

[0047] Example 2

[0048] This embodiment provides a method for preparing composite catalyst microspheres for boiler ash removal and char removal agents, including the following steps:

[0049] A1. Add 3.9 g of potassium phenolate, 5.19 g of hexachlorocyclotriphosphazene, 4 g of triethylamine, and 80 mL of chlorobenzene to a 250 mL three-necked flask equipped with a thermometer, stirrer, and reflux condenser. Mix to obtain the reaction system. Transfer the three-necked flask to an oil bath and heat to 85 °C. React at this temperature for 7 h to obtain the reactants.

[0050] A2. The reactants were allowed to cool naturally to room temperature. The three-necked flask was then transferred to a low-temperature water bath, with the bath temperature set to 0°C. Ammonia gas was continuously introduced into the three-necked flask, and the reaction was carried out at this temperature for 18 hours to obtain an intermediate. The intermediate was placed in a drying oven and polycondensed at 180°C for 25 minutes. Afterward, it was removed to obtain a solid, which is the prepared polyamino-polyphenyl condensate.

[0051] A3. 18 g of the polyamino-phenylene condensate and 55 mL of tetrahydrofuran were added to a 250 mL short-necked round-bottom flask and stirred to dissolve, obtaining a polyamino-phenylene condensate solution. 5.22 g of toluene diisocyanate was added to the above polyamino-phenylene condensate solution, and the mixture was ultrasonically dispersed at a frequency of 25 kHz for 8 min. The mixture was then stirred at room temperature for 24 h to obtain a reaction solution. The reaction solution was concentrated to 55% wt of its original volume to obtain a supramolecular polymer solution.

[0052] A4. According to weight, 6 parts sodium hydroxide, 6 parts dodecyl dimethyl betaine, 15 parts paraffin wax, 0.5 parts copper oxide powder, and 0.5 parts iron oxide powder are mixed to obtain a mixture. The mixture is then ball-milled to obtain a 220-mesh core composite material. The core composite material and supramolecular polymer solution are added to a continuous powder surface modifier at a mass ratio of 3:100 for modification. The rotor speed is 2500 r / min, the modifier temperature is 70℃, and the modification time is 8 min, yielding composite catalyst microspheres.

[0053] Example 3

[0054] This embodiment provides a method for preparing composite catalyst microspheres for boiler ash removal and char removal agents, including the following steps:

[0055] A1. Add 5.28 g of potassium phenolate, 6.92 g of hexachlorocyclotriphosphazene, 5 g of triethylamine, and 100 mL of chlorobenzene to a 250 mL three-necked flask equipped with a thermometer, stirrer, and reflux condenser. Mix to obtain the reaction system. Transfer the three-necked flask to an oil bath and heat to 90 °C. React at this temperature for 8 hours to obtain the reactants.

[0056] A2. The reactants were allowed to cool naturally to room temperature. The three-necked flask was then transferred to a low-temperature water bath at 5°C. Ammonia gas was continuously introduced into the flask, and the reaction was carried out at this temperature for 24 hours to obtain an intermediate. The intermediate was placed in a drying oven and polycondensed at 200°C for 30 minutes. The resulting solid was the prepared polyamino-phenylene condensate.

[0057] A3. Add 20g of the polyamino-phenylene condensate and 60mL of tetrahydrofuran to a 250mL short-necked round-bottom flask, stir to dissolve, and obtain a polyamino-phenylene condensate solution. Add 6.96g of toluene diisocyanate to the above polyamino-phenylene condensate solution, and disperse by ultrasonication at a frequency of 30kHz for 10min. Then stir at room temperature for 24h to obtain a reaction solution. Concentrate the reaction solution to 60% of its original volume to obtain a supramolecular polymer solution.

[0058] A4. According to weight, mix 10 parts sodium hydroxide, 10 parts dodecyl dimethyl betaine, 20 parts paraffin wax, 1 part copper oxide powder, and 1 part iron oxide powder to obtain a mixture. Add the mixture to a ball mill for ball milling to obtain a 300-mesh core composite material. Add the core composite material and supramolecular polymer solution at a mass ratio of 1:100 to a continuous powder surface modifying machine for modification. The rotor speed is 3000 r / min, the temperature of the modifying machine is 75℃, and the modification time is 10 min to obtain composite catalyst microspheres.

[0059] Example 4

[0060] This embodiment provides a method for preparing a boiler ash removal and char removal agent, including the following steps:

[0061] B1. Boric acid and phytic acid are mixed in a mass ratio of 1:1 to obtain organic acids; choline chloride and organic acids are mixed in a mass ratio of 1:2 to obtain mixed organic acids.

[0062] B2. By weight, 2 parts aluminum nitrate, 3 parts potassium nitrate, 5 parts magnesium nitrate, 3 parts composite catalyst microspheres prepared in Example 1, 3 parts mixed organic acid and 84 parts water are mixed to obtain boiler ash removal and coking agent.

[0063] Example 5

[0064] This embodiment provides a method for preparing a boiler ash removal and char removal agent, including the following steps:

[0065] B1. Boric acid and phytic acid are mixed in a mass ratio of 1:1 to obtain organic acids; choline chloride and organic acids are mixed in a mass ratio of 1:3 to obtain mixed organic acids.

[0066] B2. According to the weight, 3 parts of aluminum nitrate, 4 parts of potassium nitrate, 8 parts of magnesium nitrate, 6 parts of the composite catalyst microspheres prepared in Example 1, 6 parts of mixed organic acid and 73 parts of water are mixed to obtain boiler ash removal and coking agent.

[0067] Example 6

[0068] This embodiment provides a method for preparing a boiler ash removal and char removal agent, including the following steps:

[0069] B1. Boric acid and phytic acid are mixed in a mass ratio of 1:1 to obtain organic acids; choline chloride and organic acids are mixed in a mass ratio of 1:5 to obtain mixed organic acids.

[0070] B2. According to the weight, 5 parts of aluminum nitrate, 5 parts of potassium nitrate, 10 parts of magnesium nitrate, 10 parts of the composite catalyst microspheres prepared in Example 1, 10 parts of mixed organic acid and 60 parts of water are mixed to obtain boiler ash removal and coking agent.

[0071] Example 7

[0072] This embodiment provides a method for applying a boiler ash removal and char removal agent, including the following steps:

[0073] S1. Open the inlet valve of the boiler additive tank, pour the boiler ash removal and descaling agent prepared in Example 4 into the funnel of the additive tank, close the inlet and outlet valves after filling, and cover the funnel to prevent dust and ash from entering the funnel.

[0074] S2. Connect compressed air, open the compressed air inlet valve, and then open the discharge valve, maintaining the pressure at the discharge valve at 0.4 MPa. Ensure good atomization from the nozzle and spray into the furnace through the observation hole. During the addition process, the nozzle should extend approximately 3 cm into the observation hole; if addition is interrupted, remove the nozzle immediately. The spray angle should be as close as possible to the center of the furnace flame to avoid spraying onto the pipe wall, which would affect the decoking effect. Then close the discharge valve and inlet valve, and open the exhaust (sludge) valve to release residual gas from the container and depressurize. The dosage of the decoking agent is 1‰ of the coal mass.

[0075] Example 8

[0076] This embodiment provides a method for applying a boiler ash removal and char removal agent, including the following steps:

[0077] S1. Open the inlet valve of the boiler additive tank, pour the boiler ash removal and descaling agent prepared in Example 5 into the funnel of the additive tank, close the inlet and outlet valves after filling, and cover the funnel to prevent dust and ash from entering the funnel.

[0078] S2. Connect compressed air, open the compressed air inlet valve, and then open the discharge valve, maintaining the pressure at the discharge valve at 0.5 MPa. Ensure good atomization from the nozzle and spray into the furnace through the observation hole. During the addition process, the nozzle should extend approximately 3 cm into the observation hole; if addition is interrupted, remove the nozzle immediately. The spray angle should be as close as possible to the center of the furnace flame to avoid spraying onto the pipe wall, which would affect the decoking effect. Then close the discharge valve and inlet valve, and open the exhaust (sludge) valve to release residual gas from the container and depressurize. The dosage of the decoking agent is 1.5‰ of the coal mass.

[0079] Example 9

[0080] This embodiment provides a method for applying a boiler ash removal and char removal agent, including the following steps:

[0081] S1. Open the inlet valve of the boiler additive tank, pour the boiler ash removal and descaling agent prepared in Example 6 into the funnel of the additive tank, close the inlet and exhaust valves after filling, and cover the funnel to prevent dust and ash from entering the funnel.

[0082] S2. Connect compressed air, open the compressed air inlet valve, and then open the discharge valve, maintaining the pressure at the discharge valve at 0.7 MPa. Ensure good atomization from the nozzle and spray into the furnace through the observation hole. During the addition process, the nozzle should extend approximately 3 cm into the observation hole; if addition is interrupted, remove the nozzle immediately. The spray angle should be as close as possible to the center of the furnace flame to avoid spraying onto the pipe wall, which would affect the decoking effect. Then close the discharge valve and inlet valve, and open the exhaust (sludge) valve to release residual gas from the container and depressurize. The dosage of the decoking agent is 2‰ of the coal mass.

[0083] Comparative Example 1

[0084] The difference between this comparative example and Example 6 is that a polyamino-polyphenyl condensate solution is used instead of a supramolecular polymer solution; then the core composite material and the polyamino-polyphenyl condensate solution are added to a continuous powder surface modification machine for modification to obtain composite catalyst microspheres.

[0085] Comparative Example 2

[0086] The difference between this comparative example and Example 6 is that no paraffin was added to the core composite material when preparing the composite catalyst microspheres.

[0087] Comparative Example 3

[0088] The difference between this comparative example and Example 6 is that the organic acid obtained by mixing boric acid and phytic acid in a mass ratio of 1:1 replaces the mixed organic acid.

[0089] Performance testing:

[0090] Unit 3 of the China Coal Xinjiang Zhundong Wucaiwan North Second Power Plant (with an efficiency of 660MW), located in the Zhundong Wucaiwan Coal-Power-Chemical Industrial Park in Jimsar County, Changji Prefecture, Xinjiang, was selected as the test furnace. Boiler cleaning and descaling agents prepared in Examples 4-6 and Comparative Examples 1-3 were used sequentially to remove coke from the test furnace. The addition rate was 6 barrels (25kg / barrel) per day for 10 consecutive days. The daily addition time was fixed at 9:00 AM, following the application method of the boiler cleaning and descaling agent in Example 9. During and for four hours after the addition of the boiler descaling agent, ensure that the soot blowers in areas such as the furnace, screen, and flame deflector do not blow soot to allow sufficient reaction time between the agent and the coke layer on the tube walls of the water-cooled walls, partition screens, final superheaters, and reheaters. Then, for ten days after adding the boiler descaling agent, the inlet flue gas temperature of the screen-type reheater, the inlet flue gas temperature of the low-temperature superheater, and the desuperheating water volume of the boilers with and without the added descaling agent (prepared in Examples 4-6 and Comparative Examples 1-3) were measured. These were labeled as the blank control group, Examples 10-12, and Comparative Examples 4-6, respectively. Specific test results are shown in Table 1.

[0091] Table 1. Performance test data of the samples

[0092]

[0093] Data Analysis: Comparative analysis of the data in Table 1 shows that the boiler ash removal and descaling agents prepared in Examples 4-6 of this invention all exhibit good descaling effects on boilers in practical applications. Specifically, in Examples 10-12, the inlet flue gas temperature of the boiler's screen-type reheater (implemented with the boiler ash removal and descaling agents of Examples 4-6) decreased significantly, and the desuperheating water volume was minimal. However, in Comparative Example 4 (which used the boiler ash removal and descaling agent prepared in Comparative Example 1), replacing the supramolecular polymer solution with a polyamine-polyphenylene condensate solution weakened the shell mechanical properties of the prepared composite microsphere catalyst, reduced the expansion volume of the core composite material during expansion and bursting, thus weakening the impact force on boiler coke, reducing coke detachment, and lowering the descaling efficiency.

[0094] In Comparative Example 5 (using the boiler ash removal and descaling agent prepared in Comparative Example 2), no paraffin was added to the core composite material during the preparation of the composite catalyst microspheres. The composite catalyst microspheres did not exhibit bursting, indicating the worst descaling ability. In Comparative Example 6 (using the boiler ash removal and descaling agent prepared in Comparative Example 2), organic acids were used instead of mixed organic acids during the preparation of the composite catalyst microspheres. Choline chloride can act as a hydrogen bond acceptor, making the prepared mixed organic acids a eutectic solvent, thereby improving the solubility of boric acid and phytic acid in the prepared boiler ash removal and descaling agent. Both phytic acid and boric acid can chelate heavy metals in boiler coke.

[0095] The above description is merely an example and illustration of the structure of the present invention. Any modifications or additions made by those skilled in the art to the specific embodiments described, or any substitutions made in a similar manner, should fall within the protection scope of the present invention.

[0096] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0097] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A boiler ash removal and slag removal agent, characterized in that, The boiler ash removal and slag removal agent comprises, by weight, 2-5 parts aluminum nitrate, 3-5 parts potassium nitrate, 5-10 parts magnesium nitrate, 3-10 parts composite catalyst microspheres, 3-10 parts mixed organic acid and 60-84 parts water. The composite catalyst microspheres are obtained by modifying a supramolecular polymer solution with a mixture of sodium hydroxide, dodecyl dimethyl betaine, paraffin, copper oxide, and iron oxide as the core composite material. The supramolecular polymer solution is obtained by reacting a polyamino-polyphenyl condensate solution with toluene diisocyanate. The polyamino-polyphenyl condensate solution is obtained by dissolving the polyamino-polyphenyl condensate in tetrahydrofuran. The polyamino-polyphenyl condensate is obtained by reacting potassium phenolate, hexachlorocyclotriphosphazene, triethylamine, and chlorobenzene. The mixed organic acid is obtained by mixing boric acid, phytic acid and choline chloride; The method for preparing the composite catalyst microspheres includes the following steps: A1. Potassium phenolate, hexachlorocyclotriphosphazene, triethylamine and chlorobenzene are mixed to obtain a reaction system; the reaction system is reacted at 80-90℃ for 6-8 hours to obtain the reactants; A2. The reactants are naturally cooled to room temperature, then cooled to -5~5℃, and placed in an ammonia atmosphere for constant temperature reaction for 12-24h to obtain an intermediate; the intermediate is polycondensed at 150-200℃ for 20-30min to obtain a solid polyamino polyphenylene condensate. A3. The polyamino-polyphenyl condensate is dissolved in tetrahydrofuran to obtain a polyamino-polyphenyl condensate solution; toluene diisocyanate is added to the above polyamino-polyphenyl condensate solution, ultrasonically dispersed, and then reacted at room temperature to obtain a reaction solution; the reaction solution is concentrated to 50-60% of its original volume to obtain a supramolecular polymer solution. A4, sodium hydroxide, dodecyl dimethyl betaine, paraffin, copper oxide and iron oxide are mixed to obtain a mixture; the mixture is ball-milled to obtain a core composite material with a mesh size of 200-300; the core composite material and supramolecular polymer solution are added to a continuous powder surface modifier at a mass ratio of 1-5:100 to obtain composite catalyst microspheres.

2. The boiler ash removal and descaling agent according to claim 1, characterized in that, In step A1, the ratio of potassium phenolate, hexachlorocyclotriphosphazene, triethylamine, and chlorobenzene is 2.64-5.28 g: 3.46-6.92 g: 3-5 g: 50-100 mL; in step A3, the ratio of polyaminopolyphenylene condensate, tetrahydrofuran, and toluene diisocyanate is 15-20 g: 50-60 mL: 3.48-6.96 g; the ultrasonic dispersion frequency is 20-30 kHz, the ultrasonic dispersion time is 5-10 min, and the reaction time at room temperature is 24 h.

3. The boiler ash removal and descaling agent according to claim 1, characterized in that, In step A4, the weight ratio of sodium hydroxide, dodecyl dimethyl betaine, paraffin, copper oxide, and iron oxide is 5-10:5-10:10-20:0.1-1:0.1-1; the rotation speed of the continuous powder surface modification machine is 2000-3000 r / min, the modification temperature is 65-75℃, and the modification time is 5-10 min.

4. The boiler ash removal and descaling agent according to claim 1, characterized in that, The mixed organic acid is prepared by the following steps: Boric acid and phytic acid are mixed in a mass ratio of 1:1 to obtain organic acids; choline chloride and organic acids are mixed in a mass ratio of 1:2-5 to obtain mixed organic acids.

5. A method for preparing a boiler ash removal and descaling agent as described in any one of claims 1-4, characterized in that, Includes the following steps: Aluminum nitrate, potassium nitrate, magnesium nitrate, composite catalyst microspheres, mixed organic acid, and water are mixed to obtain a boiler ash removal and coking agent.

6. An application of a boiler ash removal and descaling agent as described in any one of claims 1-4, characterized in that, Includes the following steps: Boiler ash removal and slag removal agent is added to the addition tank, and then atomized under pressure to obtain atomized boiler ash removal and slag removal agent; the atomized boiler ash removal and slag removal agent is then sprayed into the boiler through a nozzle.

7. The application of the boiler ash removal and descaling agent according to claim 6, characterized in that, The pressure for pressurized atomization is 0.4-0.7 MPa, and the mass of the boiler ash removal and slag removal agent is 1-2‰ of the coal mass.

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