Boiler ash removal and decoking agent as well as preparation method and application thereof

Abstract

The invention discloses a boiler deashing and decoking agent as well as a preparation method and application thereof, and belongs to the technical field of decoking agents. The decoking agent is used for solving the technical problems that in the prior art, the decoking effect of a solid decoking agent is not rapid, and the decoking effect of a liquid decoking agent is poor. The boiler ash-removing and decoking agent comprises aluminum nitrate, potassium nitrate, magnesium nitrate, composite catalyst microspheres, mixed organic acid and water. The preparation method comprises the following steps: reacting a polyamino polyphenyl polycondensate solution with toluene diisocynate to obtain a supramolecular polymer solution, uniformly mixing sodium hydroxide, dodecyl dimethyl betaine, paraffin, copper oxide and ferric oxide to obtain a mixture, and coating the mixture with the supramolecular polymer solution to prepare composite catalyst microspheres; the composite catalyst microspheres can realize fixed-point blasting under a high-temperature condition. The boiler deashing and decoking agent prepared by the invention is sprayed into a boiler for decoking in an atomization manner, and has the advantages of rapid decoking reaction and good decoking effect.

Description

Technical Field

[0001] The invention relates to the technical field of decoking agents, and in particular to a boiler ash removal decoking agent and a preparation method and application thereof. Background Art

[0002] A large amount of coking will occur in the long-term operation of the boiler. Coking will cause many hazards, including: 1. It causes the temperature of the superheater and reheater to rise. If the cooling water of the superheater and reheater is turned on too high, it may even cause the pipe to overheat and be forced to reduce the load or burst due to excessive stress. 2. Coking at the water-cooled wall and horizontal flue will cause the heat transfer coefficient to decrease. In order to maintain the evaporation of the boiler, the amount of fuel needs to be increased, and the coal consumption increases; the flue gas temperature in various parts of the vertical shaft flue increases, and the flue gas temperature at the denitrification inlet is too high, affecting the reaction efficiency and service life of the catalyst. 3. Damage to the water-cooled wall tubes at the cold ash hopper. When coking is serious and large coke blocks are formed, they fall off due to disturbance and their own gravity; the wet slag removal system will face the huge risk of coke blocks falling off, causing water vapor to rise, causing unstable combustion and even fire extinguishing. The existing technology often uses boiler decoking agents to remove coke and prevent the generation of new coke.

[0003] Common types of decoking agents include liquid decoking agents and solid decoking agents. Patent application CN105670733A discloses a synergistic denitrification type liquid boiler decoking agent and a preparation method thereof. The components of the decoking agent include magnesium acetate, copper nitrate, nickel nitrate, ammonium nitrate, boric acid, cerium nitrate and water. When using a liquid decoking agent, it is only necessary to use compressed air to spray the liquid medicine in the dosing tank into the fire viewing hole of the furnace, which is simple and convenient to operate; the liquid decoking agent has the advantage of rapid decoking effect. In addition, the liquid decoking agent can be quickly dissolved and adsorbed on the coke layer through atomization, high-temperature gasification and the like, and has the advantage of rapid decoking effect. However, compared with the solid decoking agent with a blasting effect, the liquid decoking agent has the disadvantage of poor decoking effect.

[0004] Patent application CN102337169A discloses a boiler multi-element deslagging and dust cleaning energy-saving agent composition and its preparation process. The deslagging composition contains manganese carbonate, manganese sulfate, potassium permanganate, copper oxide, etc. The deslagging composition is added evenly to the coal conveyor belt or coal feeding scraper by a feeder. The above-mentioned prior art uses copper, manganese, zinc and molybdenum substances to promote the slag structure to change from the existing inhomogeneous glassy structure to a crystalline slag structure, and promotes the dense and hard coke body to develop into a porous, light, loose, fragile and brittle aggregate, thereby reducing the hardness of the coke slag. However, the above-mentioned solid decoking agent has the technical problem of pure chemical decoking and slow decoking effect.

[0005] In view of the technical defects in this aspect, a solution is now proposed. Summary of the invention

[0006] The object of the present invention is to provide a boiler ash removal and decoking agent and a preparation method and application thereof, so as to solve the technical problems in the prior art that the decoking effect of solid decoking agents is not rapid and the decoking effect of liquid decoking agents is poor.

[0007] The purpose of the present invention can be achieved through the following technical solutions: A boiler ash removal and decoking agent, which comprises, by weight, 2-5 parts of aluminum nitrate, 3-5 parts of potassium nitrate, 5-10 parts of magnesium nitrate, 3-10 parts of composite catalyst microspheres, 3-10 parts of mixed organic acid and 60-84 parts of water; The composite catalyst microspheres are prepared by using a mixture of sodium hydroxide, dodecyl dimethyl betaine, paraffin, copper oxide and iron oxide as core composite materials, and are modified by a supramolecular polymer solution; the supramolecular polymer solution is prepared by reacting a polyamino polybenzene condensation polymer solution with toluene diisocyanate, the polyamino polybenzene condensation polymer solution is prepared by dissolving a polyamino polybenzene condensation polymer in tetrahydrofuran, and the polyamino polybenzene condensation polymer is prepared by reacting potassium phenoxide, hexachlorocyclotriphosphazene, triethylamine and chlorobenzene; The mixed organic acid is obtained by mixing boric acid, phytic acid and choline chloride.

[0008] The boiler dust-removing and decoking agent prepared by the invention is a solid-liquid mixture containing a small amount of composite catalyst microspheres.

[0009] Furthermore, the method for preparing the composite catalyst microspheres comprises 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° C. for 6-8 hours to obtain a reactant; Using triethylamine as a catalyst for nucleophilic reaction and chlorobenzene as a solvent, potassium phenolate and hexachlorocyclotriphosphazene undergo nucleophilic substitution reaction to obtain the reactant. The reaction formula is as follows:

[0010] A2, the reactants are naturally cooled to room temperature, and then cooled to -5~5°C; the reactants are always placed 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°C for 20-30 minutes to obtain a solid polyamino polyphenyl polycondensate; Ammonia is introduced into the reactants, and under the action of triethylamine, an organic strong base, the reactants react with the ammonia through an elimination-addition reaction to obtain an intermediate; the intermediate is further polycondensed to prepare a polyamino polyphenyl polycondensate.

[0011] The reactants react with ammonia to prepare polyamino polyphenyl condensation products as follows:

[0012]

[0013] A3, polyamino polyphenyl condensation product is dissolved in tetrahydrofuran to obtain a polyamino polyphenyl condensation product solution; toluene diisocyanate is added to the polyamino polyphenyl condensation product solution, ultrasonically dispersed, and then reacted at room temperature to obtain a reaction solution; the reaction solution is concentrated to 50-60% of the original volume to obtain a supramolecular polymer solution; The polyaminopolyphenyl condensation polymer solution and toluene diisocyanate undergo nucleophilic addition reaction to obtain a supramolecular polymer solution; the polymer solution is concentrated to increase the content of the polymer in the solution to prepare a supramolecular polymer solution, and the reaction formula is as follows:

[0014] 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 of 200-300 mesh; the core composite material and the supramolecular polymer solution are added to a continuous powder surface modifier in a mass ratio of 1-5:100 for modification to obtain composite catalyst microspheres.

[0015] The prepared supramolecular polymer solution is used as a surface modifier to perform surface modification and coating on the core composite material to prepare composite catalyst microspheres.

[0016] Furthermore, in step A1, the amount ratio of potassium phenolate, hexachlorocyclotriphosphazene, triethylamine and chlorobenzene is 2.64-5.28g:3.46-6.92g:3-5g:50-100mL; in step A3, the amount ratio of polyaminopolyphenyl condensation product, tetrahydrofuran and toluene diisocyanate is 15-20g:50-60mL:3.48-6.96g; the frequency of ultrasonic dispersion is 20-30kHz, and the duration of ultrasonic dispersion is 5-10min; the reaction time at room temperature is 24h.

[0017] Furthermore, 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 speed of the continuous powder surface modifier is 2000-3000r / min, the modification temperature is 65-75°C, and the modification time is 5-10min.

[0018] Furthermore, 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 an organic acid; choline chloride and an organic acid are mixed in a mass ratio of 1:2-5 to obtain a mixed organic acid.

[0019] As another aspect of the present invention, a method for preparing a boiler dust removal and decoking agent comprises the following steps: Aluminum nitrate, potassium nitrate, magnesium nitrate, composite catalyst microspheres, mixed organic acid and water are mixed to obtain a boiler dust removal and decoking agent.

[0020] As another aspect of the present invention, an application of a boiler dust removal and decoking agent comprises the following steps: The boiler ash cleaning and decoking agent is added into the adding tank, and then atomized by pressurization to obtain the atomized boiler ash cleaning and decoking agent; the atomized boiler ash cleaning and decoking agent is sprayed into the boiler through the nozzle.

[0021] Furthermore, the pressurized pressure is 0.4-0.7 MPa, and the amount of the furnace ash removal and decoking agent is 1-2‰ of the mass of the coal. The present invention adopts a pressurized atomization method to spray the boiler ash removal and decoking agent into the boiler.

[0022] The present invention has the following beneficial effects: 1. The boiler ash removal and decoking agent prepared by the present 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 as organic acids; boric acid can combine with carbon atoms around the crystal lattice in the absence of water gas and block diffusion channels, which helps to reduce the reactivity of coke; phytic acid has a chelating effect on heavy metals in boiler coke. Choline chloride and organic acids are then blended, and the obtained mixed organic acid can be used as a low eutectic solvent, which can significantly improve the solubility of the mixed organic acid in deionized water.

[0023] 2. The present invention uses a mixture of sodium hydroxide, dodecyl dimethyl betaine, paraffin, copper oxide powder and iron oxide powder as the core composite material. Sodium hydroxide has strong alkalinity 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 in the boiler. However, since sodium hydroxide has strong corrosiveness and strong alkalinity, in order to avoid corrosion of the metal wall surface in the high temperature zone and low temperature zone of the boiler, sodium hydroxide is used as the core of the composite catalyst to achieve fixed-point blasting and avoid the occurrence of corrosion. Copper oxide and iron oxide both have good sulfur fixation effects. In addition, copper oxide and iron oxide can both be used as catalysts, which can help change the crystal structure of coke and thus improve the combustion performance of coke, thereby achieving the effect of further efficient decoking. Dodecyl dimethyl betaine with foaming effect and paraffin wax that can be gasified at low temperature are added to the core material. Under the high temperature of the boiler, the prepared composite catalyst microspheres are subjected to fixed-point blasting through foaming, gasification and other forms, which makes the coke block loose, thereby enhancing the decoking effect.

[0024] 3. In order to improve the impact force of the prepared composite catalyst microspheres on the coke block and the protection of the core composite material, the potassium phenolate-modified hexachlorocyclotriphosphazene of the present invention is used as a reactant; the reactant is aminated and then polycondensed to prepare a polyamino polyphenyl condensation product with multiple benzene rings and high molecular weight. Toluene diisocyanate is then added to the polycondensation product to eliminate active groups, reduce reaction activity, and further increase the amount of benzene rings and molecular weight, thereby preparing a membrane material with high mechanical properties, and improving the protection of the core composite material and the expansion bearing capacity.

[0025] 4. The boiler deashing and decoking agent synthesized by the present invention can be sprayed into the boiler by atomization. Some components of the boiler deashing and decoking agent can be rapidly gasified at high temperature, penetrate into the entire boiler heating surface with the high-temperature flue gas, and rapidly dissolve and adsorb on the coke layer. The agent quickly penetrates deep into the coke layer to react chemically, changing the sharp and hard lattice inside the coke layer, causing the coke layer to loosen, crack, fall off, and burn, which can reduce the thermal resistance of the heating surface and improve the heat transfer efficiency of the boiler. In addition, the composite catalyst microspheres have high expansion capacity and high blasting capacity at high temperatures, and can impact the boiler coke blocks with their own impact force. The boiler deashing and decoking agent prepared by the present invention has the advantages of high slag removal efficiency (the amount of boiler deashing and decoking agent is 1-2‰ of the mass of coal) and good slag removal effect (the flue gas temperature at the inlet of the screen reheater, the flue gas temperature at the inlet of the low-temperature superheater and the amount of cooling water are significantly reduced). DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1 This embodiment provides a method for preparing composite catalyst microspheres for boiler dust removal and decoking agent, comprising the following steps: A1. Add 2.64 g of potassium phenolate, 3.46 g of hexachlorocyclotriphosphazene, 3 g of triethylamine and 50 mL of chlorobenzene into a 250 mL three-necked flask equipped with a thermometer, a stirrer and a reflux condenser, and mix to obtain a reaction system. Transfer the three-necked flask to an oil bath, heat the oil bath to 80° C., and react at this temperature for 6 hours to obtain a reactant.

[0028] A2. The reactants are cooled naturally to room temperature; then the three-necked flask is transferred to a low-temperature water bath, and the temperature of the low-temperature water bath is set to -5°C; ammonia is introduced into the three-necked flask all the time, and the reaction is carried out at this temperature for 12 hours to obtain an intermediate. The intermediate is placed in a drying oven and polycondensed at 150°C for 20 minutes, and then taken out to obtain a solid, which is the prepared polyamino polyphenyl polycondensate.

[0029] A3, 15g of polyamino polyphenyl condensation product and 50mL of tetrahydrofuran are added to a 250mL short-necked round-bottom flask, stirred and dissolved to obtain a polyamino polyphenyl condensation product solution; 3.48g of toluene diisocyanate is added to the above-mentioned polyamino polyphenyl condensation product solution, ultrasonically dispersed, the ultrasonic frequency is 20kHz, the ultrasonic dispersion time is 5min, and then stirred at room temperature for 24h to obtain a reaction solution. The reaction solution is concentrated to 50% of the original volume to obtain a supramolecular polymer solution.

[0030] A4. According to weight parts, 5 parts of sodium hydroxide, 5 parts of dodecyl dimethyl betaine, 10 parts of paraffin, 0.1 parts of copper oxide powder and 0.1 parts of iron oxide powder are mixed to obtain a mixture. The mixture is added to a ball mill for ball milling to obtain a 200-mesh core composite material. The core composite material and the supramolecular polymer solution are added to a continuous powder surface modifier at a mass ratio of 1:100 for modification. The rotor speed is 2000r / min, the temperature of the modifier is 65°C, and the modification time is 5min to obtain composite catalyst microspheres.

[0031] Example 2 This embodiment provides a method for preparing composite catalyst microspheres for boiler dust removal and decoking agent, comprising the following steps: A1. Add 3.9 g of potassium phenolate, 5.19 g of hexachlorocyclotriphosphazene, 4 g of triethylamine and 80 mL of chlorobenzene into a 250 mL three-necked flask equipped with a thermometer, a stirrer and a reflux condenser, and mix to obtain a reaction system. Transfer the three-necked flask to an oil bath, heat the oil bath to 85° C., and react at this temperature for 7 hours to obtain a reactant.

[0032] A2. The reactants are cooled naturally to room temperature; then the three-necked flask is transferred to a low-temperature water bath, and the temperature of the low-temperature water bath is set to 0°C; ammonia gas is introduced into the three-necked flask all the time, and the reaction is carried out at this temperature for 18 hours to obtain an intermediate. The intermediate is placed in a drying oven and polycondensed at 180°C for 25 minutes, and then taken out to obtain a solid, which is the prepared polyamino polyphenyl polycondensate.

[0033] A3, 18g of polyamino polyphenyl condensation product and 55mL of tetrahydrofuran are added to a 250mL short-necked round-bottom flask, stirred and dissolved to obtain a polyamino polyphenyl condensation product solution; 5.22g of toluene diisocyanate is added to the above-mentioned polyamino polyphenyl condensation product solution, ultrasonically dispersed, the ultrasonic frequency is 25kHz, the ultrasonic dispersion time is 8min, and then stirred at room temperature for 24h to obtain a reaction solution. The reaction solution is concentrated to 55%wt of the original volume to obtain a supramolecular polymer solution.

[0034] A4. According to weight parts, 6 parts of sodium hydroxide, 6 parts of dodecyl dimethyl betaine, 15 parts of paraffin, 0.5 parts of copper oxide powder and 0.5 parts of iron oxide powder are mixed to obtain a mixture. The mixture is added to a ball mill for ball milling to obtain a 220-mesh core composite material. Core composite material. The core composite material and the supramolecular polymer solution are added to a continuous powder surface modifier at a mass ratio of 3:100 for modification. The rotor speed is 2500r / min, the temperature of the modifier is 70°C, and the modification time is 8min to obtain composite catalyst microspheres.

[0035] Example 3 This embodiment provides a method for preparing composite catalyst microspheres for boiler dust removal and decoking agent, comprising the following steps: A1. Add 5.28 g of potassium phenolate, 6.92 g of hexachlorocyclotriphosphazene, 5 g of triethylamine and 100 mL of chlorobenzene into a 250 mL three-necked flask equipped with a thermometer, a stirrer and a reflux condenser, and mix to obtain a reaction system. Transfer the three-necked flask to an oil bath, heat the oil bath to 90° C., and react at this temperature for 8 hours to obtain a reactant.

[0036] A2. The reactants are cooled naturally to room temperature; then the three-necked flask is transferred to a low-temperature water bath, and the temperature of the low-temperature water bath is set to 5°C; ammonia is introduced into the three-necked flask all the time, and the reaction is carried out at this temperature for 24 hours to obtain an intermediate. The intermediate is placed in a drying oven and polycondensed at 200°C for 30 minutes, and then taken out to obtain a solid, which is the prepared polyamino polyphenyl polycondensate.

[0037] A3, 20g of polyamino polyphenyl condensation product and 60mL of tetrahydrofuran are added to a 250mL short-necked round-bottom flask, stirred and dissolved to obtain a polyamino polyphenyl condensation product solution; 6.96g of toluene diisocyanate is added to the above-mentioned polyamino polyphenyl condensation product solution, ultrasonic dispersion, ultrasonic frequency is 30kHz, ultrasonic dispersion time is 10min, and then stirred at room temperature for 24h to obtain a reaction solution. The reaction solution is concentrated to 60% of the original volume to obtain a supramolecular polymer solution.

[0038] A4. According to weight parts, 10 parts of sodium hydroxide, 10 parts of dodecyl dimethyl betaine, 20 parts of paraffin, 1 part of copper oxide powder and 1 part of iron oxide powder are mixed to obtain a mixture. The mixture is added to a ball mill for ball milling to obtain a 300-mesh core composite material. Core composite material. The core composite material and the supramolecular polymer solution are added to a continuous powder surface modifier at a mass ratio of 1:100 for modification. The rotor speed is 3000r / min, the temperature of the modifier is 75°C, and the modification time is 10min to obtain composite catalyst microspheres.

[0039] Example 4 This embodiment provides a method for preparing a boiler dust removal and decoking agent, comprising the following steps: B1, boric acid and phytic acid are mixed in a mass ratio of 1:1 to obtain an organic acid; choline chloride and the organic acid are mixed in a mass ratio of 1:2 to obtain a mixed organic acid.

[0040] B2. According to parts by weight, 2 parts of aluminum nitrate, 3 parts of potassium nitrate, 5 parts of magnesium nitrate, 3 parts of the composite catalyst microspheres prepared in Example 1, 3 parts of a mixed organic acid and 84 parts of water were mixed to obtain a boiler dust removal and decoking agent.

[0041] Example 5 This embodiment provides a method for preparing a boiler dust removal and decoking agent, comprising the following steps: B1, boric acid and phytic acid are mixed in a mass ratio of 1:1 to obtain an organic acid; choline chloride and the organic acid are mixed in a mass ratio of 1:3 to obtain a mixed organic acid.

[0042] B2. According to parts by 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 a mixed organic acid and 73 parts of water were mixed to obtain a boiler dust removal and decoking agent.

[0043] Example 6 This embodiment provides a method for preparing a boiler dust removal and decoking agent, comprising the following steps: B1, boric acid and phytic acid are mixed in a mass ratio of 1:1 to obtain an organic acid; choline chloride and the organic acid are mixed in a mass ratio of 1:5 to obtain a mixed organic acid.

[0044] B2. According to parts by 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 a mixed organic acid and 60 parts of water were mixed to obtain a boiler dust removal and decoking agent.

[0045] Example 7 This embodiment provides an application method of a boiler dust removal and decoking agent, comprising the following steps: S1. Open the medicine inlet valve of the boiler adding tank, pour the boiler dust removal and decoking agent prepared in Example 4 into the funnel of the adding tank, close the medicine inlet and exhaust valves after the filling is completed, and cover the funnel cover to prevent powder ash from entering the funnel.

[0046] S2. Connect compressed air, open the compressed air inlet valve, then open the medicine outlet valve, keep the pressure of the medicine outlet valve at 0.4MPa, confirm that the nozzle is well atomized, and spray into the furnace from the furnace fire viewing hole; during the addition process, the nozzle extends into the fire viewing hole about 3cm, and it should be taken out in time when the addition is interrupted. The spray angle should be as much as possible toward the center of the furnace flame to avoid spraying to the pipe wall and affecting the decoking effect; then close the medicine outlet valve and the air inlet valve, open the exhaust (dirt) valve to remove the residual gas in the barrel for pressure relief; the amount of decoking agent used is 1‰ of the mass of the coal.

[0047] Example 8 This embodiment provides an application method of a boiler dust removal and decoking agent, comprising the following steps: S1. Open the medicine inlet valve of the boiler adding tank, pour the boiler dust removal and decoking agent prepared in Example 5 into the funnel of the adding tank, close the medicine inlet and exhaust valves after the filling is completed, and cover the funnel cover to prevent powder ash from entering the funnel.

[0048] S2. Connect compressed air, open the compressed air inlet valve, then open the medicine outlet valve, keep the pressure of the medicine outlet valve at 0.5MPa, confirm that the nozzle is well atomized, and spray into the furnace from the fire viewing hole; during the addition process, the nozzle extends into the fire viewing hole about 3cm, and it should be taken out in time when the addition is interrupted. The spray angle should be as much as possible toward the center of the furnace flame to avoid spraying to the pipe wall and affecting the decoking effect; then close the medicine outlet valve and the air inlet valve, open the exhaust (dirt) valve to remove the residual gas in the barrel for pressure relief; the amount of decoking agent used is 1.5‰ of the mass of the coal.

[0049] Example 9 This embodiment provides an application method of a boiler dust removal and decoking agent, comprising the following steps: S1. Open the medicine inlet valve of the boiler adding tank, pour the boiler dust removal and decoking agent prepared in Example 6 into the funnel of the adding tank, close the medicine inlet and exhaust valves after the filling is completed, and cover the funnel cover to prevent powder ash from entering the funnel.

[0050] S2. Connect compressed air, open the compressed air inlet valve, then open the medicine outlet valve, keep the pressure of the medicine outlet valve at 0.7MPa, confirm that the nozzle is well atomized, and spray into the furnace from the furnace fire viewing hole; during the addition process, the nozzle extends into the fire viewing hole about 3cm, and it should be taken out in time when the addition is interrupted. The spray angle should be as much as possible toward the center of the furnace flame to avoid spraying to the pipe wall and affecting the decoking effect; then close the medicine outlet valve and the air inlet valve, open the exhaust (dirt) valve to remove the remaining gas in the barrel for pressure relief; the amount of decoking agent used is 2‰ of the mass of the coal.

[0051] Comparative Example 1 The difference between this comparative example and Example 6 is that the supramolecular polymer solution is replaced by a polyamino polybenzene condensation polymer solution; and then the core composite material and the polyamino polybenzene condensation polymer solution are added to a continuous powder surface modifier for modification to obtain composite catalyst microspheres.

[0052] Comparative Example 2 The difference between this comparative example and Example 6 is that no paraffin is added to the core composite material when preparing the composite catalyst microspheres.

[0053] Comparative Example 3 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.

[0054] Performance Test: Unit 3 of the Zhongmei Xinjiang Zhundong Wucaiwan North Second Power Plant located in the Zhundong Wucaiwan Coal Power and Coal Chemical Industry Park in the north of Jimusar County, Changji Prefecture, Xinjiang was selected as a test furnace (unit efficiency of 660MW), and the boiler deashing and decoking agents prepared in Examples 4-6 and Comparative Examples 1-3 were used to decoke the test furnace. The addition amount was 6 barrels per day (25kg / barrel), and the deashing agent was added continuously for 10 days. The time for adding the deashing agent every day was fixed at 9 o'clock in the morning, and the boiler deashing and decoking agent was added according to the application method of the boiler deashing and decoking agent in Example 9. During the addition process and within four hours after the end, try to ensure that the soot blowers in the furnace, screen, flame angle and other areas do not blow soot as much as possible to ensure that the agent has enough reaction time with the coke layer on the tube wall of the heating surface such as the water-cooled wall, the partition screen, the final superheater and the reheater; then the screen reheater inlet flue gas temperature, low temperature superheater inlet flue gas temperature and cooling water volume of the boiler without adding the boiler decoking agent, adding the boiler decoking agent prepared in Example 4-6 and Comparative Example 1-3 ten days later were tested, and marked as blank control group, Example 10-12 and Comparative Example 4-6. Specific test results are shown in Table 1.

[0055] Table 1. Performance test data of samples

[0056] Data analysis: Comparative analysis of the data in Table 1 shows that the boiler deashing and decoking agents prepared in Examples 4-6 of the present invention all have good decoking effects on boilers in practical applications, as shown by the obvious decrease in the flue gas temperature at the inlet of the screen reheater of the boiler in Examples 10-12 (implementing the boiler deashing and decoking agents in Examples 4-6) and the flue gas temperature at the inlet of the low-temperature superheater, and the minimum amount of cooling water. However, in Comparative Example 4 (using the boiler deashing and decoking agent prepared in Comparative Example 1), the supramolecular polymer solution is replaced by a polyamino polybenzene polycondensate solution, and the mechanical properties of the shell of the prepared composite microsphere catalyst are weakened, and the expansion volume of the core composite material expansion explosion is reduced, thereby weakening the collision impact force on the boiler coke block, reducing the coke block shedding, and reducing the decoking efficiency.

[0057] In Comparative Example 5 (using the boiler deashing and decoking agent prepared in Comparative Example 2), no paraffin was added to the core composite material when preparing the composite catalyst microspheres. The composite catalyst microspheres did not explode, showing the worst decoking ability. In Comparative Example 6 (using the boiler deashing and decoking agent prepared in Comparative Example 2), when preparing the composite catalyst microspheres, organic acids were used instead of mixed organic acids; choline chloride can be used as a hydrogen bond acceptor, so that the prepared mixed organic acid can be used as a low eutectic solvent, thereby improving the solubility of boric acid and phytic acid in the prepared boiler deashing and decoking agent. Both phytic acid and boric acid can play a role in chelating heavy metals in boiler coke.

[0058] The above contents are merely examples and explanations of the structure of the present invention. Any modification or supplement made by a person skilled in the art to the described specific embodiments or replacement by a similar method shall fall within the protection scope of the present invention.

[0059] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0060] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. A boiler deashing and decoking agent, characterized in that: The boiler ash removal and decoking agent comprises, by weight: 2-5 parts of aluminum nitrate, 3-5 parts of potassium nitrate, 5-10 parts of magnesium nitrate, 3-10 parts of composite catalyst microspheres, 3-10 parts of mixed organic acid and 60-84 parts of water; The composite catalyst microspheres are prepared by using a mixture of sodium hydroxide, dodecyl dimethyl betaine, paraffin, copper oxide and iron oxide as core composite materials, and are modified by a supramolecular polymer solution; the supramolecular polymer solution is prepared by reacting a polyamino polybenzene condensation polymer solution with toluene diisocyanate, the polyamino polybenzene condensation polymer solution is prepared by dissolving a polyamino polybenzene condensation polymer in tetrahydrofuran, and the polyamino polybenzene condensation polymer is prepared by reacting potassium phenoxide, hexachlorocyclotriphosphazene, triethylamine and chlorobenzene; The mixed organic acid is obtained by mixing boric acid, phytic acid and choline chloride.

2. A boiler deashing and decoking agent according to claim 1, characterized in that: The preparation method of the composite catalyst microspheres comprises 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° C. for 6-8 hours to obtain a reactant; A2, the reactants are naturally cooled to room temperature, then cooled to -5~5°C, placed 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°C for 20-30 minutes to obtain a solid polyamino polybenzene polycondensate; A3, polyamino polyphenyl condensation product is dissolved in tetrahydrofuran to obtain a polyamino polyphenyl condensation product solution; toluene diisocyanate is added to the polyamino polyphenyl condensation product solution, ultrasonically dispersed, and then reacted at room temperature to obtain a reaction solution; the reaction solution is concentrated to 50-60% of the 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 of 200-300 mesh; the core composite material and the supramolecular polymer solution are added to a continuous powder surface modifier in a mass ratio of 1-5:100 for modification to obtain composite catalyst microspheres.

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

4. A boiler deashing and decoking agent according to claim 2, 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 speed of the continuous powder surface modifier is 2000-3000r / min, the modification temperature is 65-75°C, and the modification time is 5-10min.

5. A boiler deashing and decoking 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 an organic acid; choline chloride and an organic acid are mixed in a mass ratio of 1:2-5 to obtain a mixed organic acid.

6. A method for preparing a boiler dust removal and decoking agent according to any one of claims 1 to 5, characterized in that: The following steps are involved: Aluminum nitrate, potassium nitrate, magnesium nitrate, composite catalyst microspheres, mixed organic acid and water are mixed to obtain a boiler dust removal and decoking agent.

7. A use of a boiler deashing and decoking agent as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: The boiler ash cleaning and decoking agent is added into the adding tank, and then atomized by pressurization to obtain the atomized boiler ash cleaning and decoking agent; the atomized boiler ash cleaning and decoking agent is sprayed into the boiler through the nozzle.

8. The use of a boiler deashing and decoking agent according to claim 7, characterized in that: The pressure of pressurized atomization is 0.4-0.7MPa, and the mass of boiler deashing and decoking agent is 1-2‰ of the mass of coal.

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