CN115651730A - Strong-permeability decoking agent for boiler - Google Patents
Strong-permeability decoking agent for boiler Download PDFInfo
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Abstract
The invention relates to the technical field of decoking agents, in particular to a strong permeability decoking agent for a boiler, which comprises the following raw materials in parts by weight: 0.5-0.7 part of copper sulfate, 1.2-1.8 parts of magnesium sulfate, 13.5-16.5 parts of magnesium nitrate, 6-8 parts of potassium sulfate, 0.3-0.5 part of boric acid, 0.1-0.4 part of decoking catalyst, 0.5-1.0 part of dispersant and 80-90 parts of water. The decoking agent can effectively promote the combustion of carbon in the coke when being sprayed on the coke layer, thereby being beneficial to reducing the thickness of the coke lump layer and promoting the falling of the coke, and simultaneously, after the decoking catalyst is pretreated, the decoking catalyst can be intercepted in the coke layer to change the hard crystal structure in the coke layer, thereby not only improving the utilization efficiency of the decoking agent, but also effectively inhibiting the generation of subsequent new coke and simultaneously playing the role of inhibiting the growth of the coke for a long time.
Description
Technical Field
The invention relates to the technical field of decoking agents, in particular to a strong permeability decoking agent for a boiler.
Background
At present, most of power generation facilities in China still use a coal burning method and can last for a long time. In the existing coal-fired method, coking is a common problem in the operation of coal-fired boilers. The ash in the fuel is mostly melted into a liquid state or a softened state at a high temperature, and the temperature is lower as approaching the water wall from the center of the combustion flame to the outside due to the heat absorption of the water wall. Under normal conditions, ash will change from a liquid to a softened and thus solid state as the temperature decreases. If the ash still remains softened and encounters the heated surface, it cools and adheres to the heated surface, forming coke. The boiler coking of large-scale unit power plant is more serious, often needs to carry out artifical decoking in the operation process, still need to shut down the stove and carry out artifical coking when the coking is serious, seriously influences coal fired power plant's safe operation, has increased workman's intensity of labour, and decoking work also has very big potential safety hazard simultaneously.
For example, the invention patent with publication number CN108795534A discloses a boiler decoking agent, which comprises an auxiliary agent, a solvent, a composite deashing material and a composite combustion-supporting component, and can play a role in catalyzing coal combustion in the combustion process of coal during use, and also can be used as a sintering auxiliary agent to sinter suspended inorganic substances in a boiler at high temperature, so that inorganic substance particles grow up and settle, and the generation of coke scale is reduced; although this decoking agent can play certain decoking effect, but the decoking effect is general, it is not good to the effect is clear away on the decoking layer of boiler internal thickness, and this decoking agent sprays behind the coke layer, under the action of gravity, the decoking agent can flow downwards along the boiler wall, pile up in the boiler lower part in a large number, only a small amount of decoking agent in the coke layer that leads to the boiler upper portion, thereby the coke layer that leads to the boiler upper portion need spray the decoking agent repeatedly a large amount and just can play the decoking effect, the utilization ratio that leads to the decoking agent is lower, furthermore, the decoking agent that sprays acts on behind the coke layer, most decoking agent can be along with droing of coke layer and run off, lead to the boiler inner wall can grow new coke very fast, can't realize disposable, long-term effectual purpose.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a strong-permeability decoking agent for a boiler, which can efficiently remove a coke layer in the boiler, can be trapped in the coke layer when in use, can effectively remove the coke layer on the upper part of the boiler, and can effectively inhibit the generation of subsequent new coke, thereby achieving the purposes of one-time use and long-term effectiveness.
In order to achieve the purpose, the invention provides the following technical scheme:
the strong-permeability decoking agent for the boiler comprises the following raw materials in parts by weight: 0.5-0.7 part of copper sulfate, 1.2-1.8 parts of magnesium sulfate, 13.5-16.5 parts of magnesium nitrate, 6-8 parts of potassium sulfate, 0.3-0.5 part of boric acid, 0.1-0.4 part of decoking catalyst, 0.5-1.0 part of dispersant and 80-90 parts of water; the dispersing agent is prepared from stearic acid and higher fatty alcohol in a mass ratio of 1: (1.2-1.8).
As a further preferable embodiment of the present invention, the preparation method of the decoking catalyst is as follows:
1) Placing sodium hydroxide solution in a container, preheating in water bath at 60-70 deg.C for 10-30min, adding catalyst and piperidine, and stirring to obtain mixed solution;
2) Adding deionized water, ethanol and a triblock copolymer P123 into the mixed solution, uniformly mixing, dropwise adding a hydrochloric acid solution to adjust the pH value of the system to be 5.0-5.6, uniformly dispersing by ultrasonic wave, placing the mixture into a water bath, reacting at 30-34 ℃ for 45-50h, aging for 23-27h, washing, filtering and drying the product, and roasting for 6-10h to obtain a composite catalyst;
3) Dissolving nickel nitrate hexahydrate and cobalt nitrate hexahydrate in deionized water, adding a composite catalyst after full dissolution, taking out after full impregnation, drying, putting into a tube furnace, introducing argon, heating to 500-530 ℃, calcining for 2-5h, naturally cooling to room temperature, crushing and grinding to obtain the decoking catalyst.
In a more preferred embodiment of the present invention, the ratio of the amount of the sodium hydroxide solution, the catalyst and the piperidine in the mixed solution is (50 to 80) mL: (1-3) g: (0.01-0.05) g;
the concentration of the sodium hydroxide solution is 0.2-0.4mol/L.
In a further preferred embodiment of the present invention, the ratio of the amount of the mixed solution, deionized water, ethanol, and triblock copolymer P123 is (60-90) mL: (130-180) g: (76-85) g: (2-4) g;
the concentration of the hydrochloric acid solution is 0.5-0.8mol/L;
the aging temperature is 70-76 ℃;
the roasting temperature is 550-580 ℃.
As a further preferable scheme of the invention, the dosage proportion of the nickel nitrate hexahydrate, the cobalt nitrate hexahydrate, the deionized water and the composite catalyst is (2.7-3.0) g: (1.5-2.3) g: (5-13) mL: (1-2) g;
the temperature rise speed of the calcination is 3-7 ℃/min.
As a further preferred embodiment of the present invention, the preparation method of the catalyst is as follows:
1) Uniformly mixing tetraethyl orthosilicate, tetrapropylammonium hydroxide and deionized water in a beaker, fully stirring at 80-85 ℃, then transferring to a high-pressure reaction kettle for crystallization for 3-6h, and naturally cooling to room temperature to obtain seed crystals for later use;
2) Adding piperidine into deionized water, mixing uniformly, sequentially adding sodium hydroxide and aluminum sulfate octadecahydrate, continuously stirring until the solution is clear, adding silica sol, fully stirring, adding seed crystals to obtain mother liquor, transferring the mother liquor into a high-pressure reaction kettle for crystallization for 70-80h, performing suction filtration, washing and drying, and roasting for 6-10h to obtain the catalyst.
As a further preferable embodiment of the present invention, the molar ratio of tetraethyl orthosilicate, tetrapropylammonium hydroxide and deionized water is 1: (0.12-0.18): (13-17);
the crystallization temperature is 120-126 ℃.
As a further preferable embodiment of the present invention, the concentration of the silica sol is 30 to 36wt%;
in the mother liquor, the mol ratio of silicon dioxide, aluminum oxide, piperidine, sodium oxide and water is 1: (0.01-0.02): (0.2-0.3): (0.05-0.08): (25-30);
the addition amount of the seed crystal is 1-3% of the total amount of the mother liquor;
the crystallization temperature is 140-150 ℃;
the roasting temperature is 550-580 ℃.
A strong permeability decoking agent for a boiler is prepared by the following steps:
1) Weighing the raw material components according to the proportion for later use, adding tetrabutyl titanate and sodium fluoride into oleic acid, fully stirring at room temperature to obtain a reaction solution, adding a decoking catalyst into the reaction solution, transferring the reaction solution into a hydrothermal kettle, preserving heat for 23-26h at 200-210 ℃ after sealing, then adding deionized water into the hydrothermal kettle, packaging the hydrothermal kettle after stirring, preserving heat for 23-26h at 300-320 ℃, adding a product into ethanol after the reaction is finished, standing for 6-10h, repeatedly cleaning the obtained precipitate with ethanol, and drying to obtain a pretreatment decoking agent catalyst;
2) Pouring copper sulfate, magnesium nitrate, magnesium sulfate and potassium sulfate into a container, carrying out first round of stirring, adding a dispersing agent after the stirring is finished, carrying out second round of stirring, adding boric acid after the stirring is finished, slowly adding water during the stirring process, adding a pretreatment decoking agent catalyst after the stirring is finished, and standing for 1-2 hours after the stirring to obtain the required decoking agent.
In a further preferred embodiment of the present invention, the ratio of the amount of tetrabutyl titanate, sodium fluoride, oleic acid, deionized water and ethanol is (4.5-5.3) g: (0.05-0.07) g: (33-38) g: (1.5-2.0) g: (200-280) mL;
the mass ratio of the decoking catalyst to the reaction liquid is 1: (15-23).
Compared with the prior art, the invention has the beneficial effects that:
in the invention, an active seed crystal assisted method is adopted, piperidine is taken as a template agent to prepare the catalyst, the catalyst is an acid catalyst, has an acid active site, can generate a large amount of free radicals, and enhances reactions such as hydrogen polymerization, proton adsorption, isomerization and the like, so that the combustion of carbon in coke is promoted, the thickness of the coke is reduced, and the falling of the coke is promoted; in order to avoid the phenomenon that the generated coke blocks the pore channel of the catalyst in the cracking process to cause the inactivation of the catalyst, the invention takes the triblock copolymer P123 as the template agent under the alkaline condition, a layer of core shell with ordered mesopores covers the outside of the catalyst, and the mesopores of the core shell are communicated with the pore channel of the catalyst, so that a reaction substrate is easier to approach the acid site of the catalyst, and a primary cracking product can be quickly transferred to the foreign currency of the catalyst through the mesopores, thereby avoiding the occurrence of deep cracking, inhibiting the formation of the coke, avoiding the phenomenon that the catalyst is inactivated due to the blockage of the pore channel, and being conductive to improving the activity of the catalyst; moreover, the mesoporous of the core shell increases the surface area of the composite catalyst, so that more sites are exposed, and the subsequent doping of metal nickel and metal cobalt is facilitated.
In the invention, in order to further improve the catalytic cracking effect, the nickel-cobalt compound is doped into the composite catalyst to obtain the decoking catalyst, on one hand, the overall acidity of the composite catalyst can be adjusted, so that the weak acid sites in the composite catalyst are obviously increased, the cracking process can be promoted along with the increase of the weak acid sites, the cracking of coke is promoted, and the formation of coke can be slowed down, thereby realizing high-efficiency decoking and effectively inhibiting the generation of subsequent new coke; moreover, the catalyst can generate a monomolecular cracking reaction of high-content ethylene and propylene through the doped nickel-cobalt compound, so that the formation of a large amount of extra free radicals is reduced, more gas products are generated, and the generated gas can generate an impact effect on a coke layer in the escaping process, so that the bonding strength between coke and the inner wall is reduced, and the coke is easy to fall off; on the other hand, the nickel-cobalt compound can absorb or release electrons from the carbenium ion or the hydrocarbon in the reaction process, so that the formation of the carbenium ion is promoted, the carbenium ion is used as an active intermediate and is easy to break at beta position to generate new carbenium ion and olefin, the new carbenium ion is continuously transferred and broken to initiate further cracking, and the decoking efficiency can be further improved.
In order to better retain the decoking agent in the residual coke layer and play a role in slowing down the formation of new coke for a long time, the invention pre-treats the decoking catalyst, takes the decoking catalyst as a substrate, adopts a two-step solvent method, utilizes titanium dioxide crystal growth in hydrothermal reaction under an acidic condition as a growth unit, and generates aggregation growth along the crystallography consistent direction, so that the titanium dioxide nanocrystals with necklace-shaped structures are deposited on the decoking catalyst, each titanium dioxide nanocrystal with necklace-shaped structures consists of a plurality of basic units with square bipyramidal structures, as the square bipyramidal structures have smaller interfaces at two ends and larger interfaces and smooth crystal faces at two ends and the middle, a plurality of notches with small interfaces and convex edges with large interfaces exist in each titanium dioxide nanocrystal, so that the titanium dioxide nanocrystals with necklace-shaped structures can be embedded into gaps of the residual coke layer through the notches with small interfaces, and are limited and fixed in the coke layer through the convex edges with large interfaces, thereby the pre-treated decoking catalyst can be retained in the residual coke layer, and the subsequent effective generation of new coke can be inhibited.
The decoking agent can effectively promote the combustion of carbon in the coke when being sprayed on the coke layer, thereby being beneficial to reducing the thickness of coke block layer accumulation and promoting the falling of the coke, and simultaneously, after the decoking catalyst is pretreated, the decoking catalyst can permeate into the deep layer inside the coke block and is limited and fixed, thereby being trapped in the coke layer to change the hard crystal structure inside the coke layer, promoting the coking to be changed into the uniform brown eye shape like bread, loose, upwarping, cracking, falling and combustion, reducing the loss of the decoking agent under the action of gravity, not only improving the utilization efficiency of the decoking agent, but also effectively inhibiting the generation of subsequent new coke and simultaneously playing the effect of inhibiting the growth of the coke for a long time.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
The strong permeability decoking agent for the boiler comprises the following raw materials in parts by weight: 0.5 part of copper sulfate, 1.2 parts of magnesium sulfate, 13.5 parts of magnesium nitrate, 6 parts of potassium sulfate, 0.3 part of boric acid, 0.1 part of decoking catalyst, 0.5 part of dispersant and 80 parts of water;
wherein the dispersant is prepared from stearic acid and higher fatty alcohol according to a mass ratio of 1: 1.2;
the preparation method of the decoking agent comprises the following steps:
1) Weighing the raw material components according to the ratio for later use, adding 4.5g of tetrabutyl titanate and 0.05g of sodium fluoride into 33g of oleic acid, and fully stirring at room temperature to obtain a reaction solution, wherein the mass ratio of the reaction solution to the raw material components is 1:15, adding a decoking catalyst into the reaction liquid, fully dispersing, transferring to a hydrothermal kettle, sealing, keeping the temperature at 200 ℃ for 23 hours, then adding 1.5g of deionized water into the hydrothermal kettle, fully stirring, packaging the hydrothermal kettle, keeping the temperature at 300 ℃ for 23 hours, after the reaction is finished, adding a product into 200mL of ethanol, standing for 6 hours, repeatedly cleaning the obtained precipitate with ethanol, and drying to obtain a pretreatment decoking catalyst;
2) Pouring copper sulfate, magnesium nitrate, magnesium sulfate and potassium sulfate into a container, carrying out first-round stirring at a stirring speed of 30r/min for 5min, adding a dispersing agent after the stirring is finished, carrying out second-round stirring at a stirring speed of 60r/min for 15min, adding boric acid after the stirring is finished, stirring at a speed of 130r/min for 30min, slowly adding water during the stirring process, adding a pretreatment decoking agent catalyst after the stirring is finished, continuing stirring for 10min, and standing for 1h to obtain the required decoking agent.
The preparation method of the decoking catalyst comprises the following steps:
1) Placing 50mL of 0.2mol/L sodium hydroxide solution into a container, preheating in a water bath at 60 ℃ for 10min, then adding 1g of catalyst and 0.01g of piperidine, and stirring at 500r/min for 30min to obtain a mixed solution for later use;
2) Adding 130g of deionized water, 76g of ethanol and 2g of triblock copolymer P123 into 60mL of mixed solution, uniformly mixing, dropwise adding 0.5mol/L hydrochloric acid solution, adjusting the pH value of the system to 5.0, uniformly dispersing by using ultrasonic waves, placing the mixture in a water bath kettle, reacting at 30 ℃ for 45 hours, heating to 70 ℃, aging for 23 hours, washing, filtering and drying a product, and roasting at 550 ℃ for 6 hours to obtain a composite catalyst;
3) 2.7g of nickel nitrate hexahydrate and 1.5g of cobalt nitrate hexahydrate are dissolved in 5mL of deionized water, 1g of composite catalyst is added after full dissolution, the materials are taken out after full immersion, the materials are dried for 20 hours at 60 ℃, then the materials are placed into a tube furnace, argon is introduced, the temperature is raised to 500 ℃ at the rate of 3 ℃/min, the materials are calcined for 2 hours, the materials are naturally cooled to the room temperature, and the materials are crushed and ground to obtain the decoking catalyst.
The preparation method of the catalyst comprises the following steps:
1) According to a molar ratio of 1:0.12:13, uniformly mixing tetraethyl orthosilicate, tetrapropylammonium hydroxide and deionized water in a beaker, stirring for 2 hours at the temperature of 80 ℃ at 100r/min, then transferring to a high-pressure reaction kettle, crystallizing for 3 hours at the temperature of 120 ℃, and naturally cooling to room temperature to obtain seed crystals for later use;
2) Adding piperidine into deionized water, uniformly mixing, sequentially adding sodium hydroxide and aluminum sulfate octadecahydrate, continuously stirring until the solution is clear, adding 30wt% of silica sol, fully stirring, and adding seed crystals to obtain mother liquor, wherein in the mother liquor, the molar ratio of silicon dioxide, aluminum oxide, piperidine, sodium oxide and water is 1:0.01:0.2:0.05:25, transferring the mother liquor into a high-pressure reaction kettle, crystallizing at 140 ℃ for 70 hours, performing suction filtration, washing and drying, and roasting at 550 ℃ for 6 hours to obtain the catalyst, wherein the addition amount of the seed crystal is 1% of the total amount of the mother liquor.
Example 2
The strong permeability decoking agent for the boiler comprises the following raw materials in parts by weight: 0.6 part of copper sulfate, 1.5 parts of magnesium sulfate, 14.6 parts of magnesium nitrate, 7 parts of potassium sulfate, 0.4 part of boric acid, 0.3 part of decoking catalyst, 0.8 part of dispersant and 85 parts of water;
wherein the dispersant is prepared from stearic acid and higher fatty alcohol according to a mass ratio of 1: 1.5;
the preparation method of the decoking agent comprises the following steps:
1) Weighing the raw material components according to the proportion for later use, adding 5.0g of tetrabutyl titanate and 0.06g of sodium fluoride into 35g of oleic acid, and fully stirring at room temperature to obtain a reaction solution, wherein the mass ratio of the raw material components is 1:20, adding a decoking catalyst into the reaction liquid, fully dispersing, transferring to a hydrothermal kettle, sealing, keeping the temperature at 205 ℃ for 25 hours, then adding 1.8g of deionized water into the hydrothermal kettle, fully stirring, packaging the hydrothermal kettle, keeping the temperature at 310 ℃ for 25 hours, after the reaction is finished, adding a product into 250mL of ethanol, standing for 8 hours, repeatedly cleaning the obtained precipitate with ethanol, and drying to obtain a pretreatment decoking catalyst;
2) Pouring copper sulfate, magnesium nitrate, magnesium sulfate and potassium sulfate into a container, carrying out first round of stirring at a stirring speed of 40r/min for 8min, adding a dispersing agent after the stirring is finished, carrying out second round of stirring at a stirring speed of 80r/min for 20min, adding boric acid after the stirring is finished, stirring at 150r/min for 40min, slowly adding water during the stirring process, adding a pretreatment decoking agent catalyst after the stirring is finished, continuing to stir for 20min, and standing for 1.5h to obtain the required decoking agent.
The preparation method of the decoking catalyst comprises the following steps:
1) Putting 70mL of 0.3mol/L sodium hydroxide solution into a container, preheating in 65 ℃ water bath for 20min, then adding 2g of catalyst and 0.04g of piperidine, and stirring at 650r/min for 40min to obtain a mixed solution for later use;
2) Adding 150g of deionized water, 82g of ethanol and 3g of triblock copolymer P123 into 80mL of mixed solution, uniformly mixing, dropwise adding 0.6mol/L hydrochloric acid solution, adjusting the pH value of the system to 5.3, uniformly dispersing by using ultrasonic waves, placing the mixture into a water bath kettle, reacting for 46h at 32 ℃, heating to 72 ℃, aging for 24h, washing, filtering and drying a product, and roasting for 8h at 570 ℃ to obtain a composite catalyst;
3) 2.8g of nickel nitrate hexahydrate and 1.6g of cobalt nitrate hexahydrate are dissolved in 10mL of deionized water, 1.5g of composite catalyst is added after full dissolution, the materials are taken out after full impregnation, the materials are dried for 24 hours at 70 ℃, then the materials are put into a tubular furnace, argon is introduced, the temperature is raised to 510 ℃ at the speed of 5 ℃/min, the materials are calcined for 3 hours, the materials are naturally cooled to the room temperature, and the materials are crushed and ground to obtain the decoking catalyst.
The preparation method of the catalyst comprises the following steps:
1) According to a molar ratio of 1:0.15:16, uniformly mixing tetraethyl orthosilicate, tetrapropylammonium hydroxide and deionized water in a beaker, stirring for 4 hours at 82 ℃ at 200r/min, then transferring to a high-pressure reaction kettle, crystallizing for 5 hours at 122 ℃, and naturally cooling to room temperature to obtain seed crystals for later use;
2) Adding piperidine into deionized water, uniformly mixing, sequentially adding sodium hydroxide and aluminum sulfate octadecahydrate, continuously stirring until the solution is clear, adding 32wt% of silica sol, fully stirring, and adding seed crystals to obtain mother liquor, wherein in the mother liquor, the molar ratio of silicon dioxide, aluminum oxide, piperidine, sodium oxide and water is 1:0.02:0.3:0.07:28, transferring the mother liquor into a high-pressure reaction kettle, crystallizing at 145 ℃ for 75h, performing suction filtration, washing, drying, and roasting at 570 ℃ for 8h to obtain the catalyst, wherein the addition amount of the seed crystal is 2% of the total amount of the mother liquor.
Example 3
The strong permeability decoking agent for the boiler comprises the following raw materials in parts by weight: 0.7 part of copper sulfate, 1.8 parts of magnesium sulfate, 16.5 parts of magnesium nitrate, 8 parts of potassium sulfate, 0.5 part of boric acid, 0.4 part of decoking catalyst, 1 part of dispersant and 90 parts of water;
wherein the dispersant is prepared from stearic acid and higher fatty alcohol according to a mass ratio of 1: 1.8;
the preparation method of the decoking agent comprises the following steps:
1) Weighing the raw material components according to the ratio for later use, adding 5.3g of tetrabutyl titanate and 0.07g of sodium fluoride into 38g of oleic acid, and fully stirring at room temperature to obtain a reaction solution, wherein the mass ratio of the reaction solution to the raw material components is 1:23, adding a decoking catalyst into the reaction liquid, fully dispersing, transferring to a hydrothermal kettle, sealing, keeping the temperature at 210 ℃ for 26 hours, adding 2.0g of deionized water into the hydrothermal kettle, fully stirring, packaging the hydrothermal kettle, keeping the temperature at 320 ℃ for 26 hours, after the reaction is finished, adding a product into 280mL of ethanol, standing for 10 hours, repeatedly cleaning the obtained precipitate with ethanol, and drying to obtain a pretreatment decoking catalyst;
2) Pouring copper sulfate, magnesium nitrate, magnesium sulfate and potassium sulfate into a container, carrying out first-round stirring at a stirring speed of 50r/min for 10min, adding a dispersing agent after the stirring is finished, carrying out second-round stirring at a stirring speed of 100r/min for 25min, adding boric acid after the stirring is finished, stirring for 50min at 180r/min, slowly adding water during the stirring process, adding a pretreatment decoking agent catalyst after the stirring is finished, continuing stirring for 30min, and standing for 2h to obtain the required decoking agent.
The preparation method of the decoking catalyst comprises the following steps:
1) Placing 80mL of 0.4mol/L sodium hydroxide solution into a container, preheating in 70 ℃ water bath for 30min, then adding 3g of catalyst and 0.05g of piperidine, and stirring at 800r/min for 50min to obtain a mixed solution for later use;
2) Adding 180g of deionized water, 85g of ethanol and 4g of triblock copolymer P123 into 90mL of mixed solution, uniformly mixing, dropwise adding 0.8mol/L hydrochloric acid solution, adjusting the pH value of the system to 5.6, uniformly dispersing by using ultrasonic waves, placing the mixture into a water bath kettle, reacting for 50h at 34 ℃, heating to 76 ℃, aging for 27h, washing, filtering and drying a product, and roasting for 10h at 580 ℃ to obtain a composite catalyst;
3) 3.0g of nickel nitrate hexahydrate and 2.3g of cobalt nitrate hexahydrate are dissolved in 13mL of deionized water, 2g of composite catalyst is added after full dissolution, the mixture is taken out after full impregnation, dried at 80 ℃ for 26h, then placed in a tubular furnace, argon is introduced, the temperature is raised to 530 ℃ at the rate of 7 ℃/min, and the mixture is calcined for 5h, naturally cooled to the room temperature, crushed and ground to obtain the decoking catalyst.
The preparation method of the catalyst comprises the following steps:
1) According to a molar ratio of 1:0.18:17, uniformly mixing tetraethyl orthosilicate, tetrapropylammonium hydroxide and deionized water in a beaker, stirring for 5 hours at 85 ℃ at 300r/min, then transferring to a high-pressure reaction kettle, crystallizing for 6 hours at 126 ℃, and naturally cooling to room temperature to obtain seed crystals for later use;
2) Adding piperidine into deionized water, uniformly mixing, sequentially adding sodium hydroxide and aluminum sulfate octadecahydrate, continuously stirring until the solution is clear, adding 36wt% of silica sol, fully stirring, and adding seed crystals to obtain mother liquor, wherein in the mother liquor, the molar ratio of silicon dioxide, aluminum oxide, piperidine, sodium oxide and water is 1:0.02:0.3:0.08:30, the addition amount of the seed crystal is 3 percent of the total amount of the mother liquor, the mother liquor is transferred to a high-pressure reaction kettle, crystallized for 80 hours at the temperature of 150 ℃, filtered, washed and dried, and then roasted for 10 hours at the temperature of 580 ℃ to obtain the catalyst.
Comparative example 1: this comparative example is essentially the same as example 1 except that a catalyst was used instead of the decoking catalyst.
Comparative example 2: this comparative example is essentially the same as example 1 except that a catalyst was used instead of the composite catalyst in the preparation of the decoking catalyst.
Comparative example 3: this comparative example is essentially the same as example 1 except that cobalt nitrate hexahydrate was not added during the preparation of the decoking catalyst.
Comparative example 4: this comparative example is essentially the same as example 1 except that nickel nitrate hexahydrate was not added during the preparation of the decoking catalyst.
Comparative example 5: this comparative example is essentially the same as example 1 except that the decoking catalyst was not pretreated during the preparation of the decoking agent.
Test run 1:
the decoking agent samples provided in examples 1 to 3 and comparative examples 1 to 5 were added to a boiler, and the decoking rate thereof was measured, wherein the boiler was weighed W1, the boiler was normally used, baked at 1200 ℃ for 1 hour, weighed W2, 5% o of the decoking agent sample was applied to the boiler, left at room temperature for two hours, and then rinsed with a sponge under flow of hot water, dried, and weighed W3, and the decoking rate was obtained gravimetrically,% decoking = [ W2-W3)/(W2-W1) ] x 100%, and after decoking, the removal of coke from the inner wall of the boiler was observed, and the results are shown in table 1.
TABLE 1
Test run 2:
the coke-cleaned boiler is normally used, the working temperature is 1200 ℃, the coke-cleaned boiler is continuously used for 30d, the weight W4 is emphasized, the weight gain rate of the boiler is obtained by a gravimetric method, and the weight gain rate = (W4-W3)/W3 multiplied by 100 percent, and the results are shown in the following table 2.
TABLE 2
| Example 1 | Example 2 | Example 3 | Comparative example 1 | |
| The weight gain rate% | 3.8 | 3.1 | 3.5 | 8.2 |
| Comparative example 2 | Comparative example 3 | Comparative example 4 | Comparative example 5 | |
| The weight gain rate% | 7.1 | 5.6 | 5.3 | 16.5 |
As can be seen from tables 1 and 2, the decoking agent of the present invention not only can efficiently remove the coke layer in the boiler, but also can be trapped in the coke layer when in use, which can effectively remove the coke layer on the upper part of the boiler, and can also effectively inhibit the generation of new coke, thereby achieving the effect of inhibiting the coke growth for a long time.
The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims (10)
1. The strong permeability decoking agent for the boiler is characterized by comprising the following raw materials in parts by weight: 0.5-0.7 part of copper sulfate, 1.2-1.8 parts of magnesium sulfate, 13.5-16.5 parts of magnesium nitrate, 6-8 parts of potassium sulfate, 0.3-0.5 part of boric acid, 0.1-0.4 part of decoking catalyst, 0.5-1.0 part of dispersant and 80-90 parts of water; the dispersing agent is prepared from stearic acid and higher fatty alcohol in a mass ratio of 1: (1.2-1.8).
2. The strong permeability decoking agent for the boiler as claimed in claim 1, wherein the preparation method of the decoking catalyst is as follows:
1) Placing sodium hydroxide solution in a container, preheating in water bath at 60-70 deg.C for 10-30min, adding catalyst and piperidine, and stirring to obtain mixed solution;
2) Adding deionized water, ethanol and a triblock copolymer P123 into the mixed solution, uniformly mixing, dropwise adding a hydrochloric acid solution to adjust the pH value of the system to be 5.0-5.6, uniformly dispersing by ultrasonic wave, placing the mixture into a water bath, reacting at 30-34 ℃ for 45-50h, aging for 23-27h, washing, filtering and drying the product, and roasting for 6-10h to obtain a composite catalyst;
3) Dissolving nickel nitrate hexahydrate and cobalt nitrate hexahydrate in deionized water, adding a composite catalyst after full dissolution, taking out after full impregnation, drying, putting into a tube furnace, introducing argon, heating to 500-530 ℃, calcining for 2-5h, naturally cooling to room temperature, crushing and grinding to obtain the decoking catalyst.
3. The strong permeability decoking agent for the boiler as claimed in claim 2, wherein the dosage ratio of the sodium hydroxide solution, the catalyst and the piperidine in the mixed solution is (50-80) mL: (1-3) g: (0.01-0.05) g;
the concentration of the sodium hydroxide solution is 0.2-0.4mol/L.
4. The strong permeability decoking agent for the boiler as claimed in claim 2, wherein the dosage ratio of the mixed solution, the deionized water, the ethanol and the triblock copolymer P123 is (60-90) mL: (130-180) g: (76-85) g: (2-4) g;
the concentration of the hydrochloric acid solution is 0.5-0.8mol/L;
the aging temperature is 70-76 ℃;
the roasting temperature is 550-580 ℃.
5. The strongly-permeable decoking agent for the boiler according to claim 2, wherein the dosage ratio of nickel nitrate hexahydrate, cobalt nitrate hexahydrate, deionized water and the composite catalyst is (2.7-3.0) g: (1.5-2.3) g: (5-13) mL: (1-2) g;
the temperature rise speed of the calcination is 3-7 ℃/min.
6. The strongly-permeable decoking agent for the boiler as claimed in claim 2, wherein the preparation method of the catalyst is as follows:
1) Uniformly mixing tetraethyl orthosilicate, tetrapropylammonium hydroxide and deionized water in a beaker, fully stirring at 80-85 ℃, then transferring to a high-pressure reaction kettle for crystallization for 3-6h, and naturally cooling to room temperature to obtain seed crystals for later use;
2) Adding piperidine into deionized water, mixing uniformly, sequentially adding sodium hydroxide and aluminum sulfate octadecahydrate, continuously stirring until the solution is clear, adding silica sol, fully stirring, adding seed crystals to obtain mother liquor, transferring the mother liquor into a high-pressure reaction kettle for crystallization for 70-80h, performing suction filtration, washing and drying, and roasting for 6-10h to obtain the catalyst.
7. The strong permeability decoking agent for the boiler as claimed in claim 6, wherein the mole ratio of tetraethyl orthosilicate, tetrapropylammonium hydroxide and deionized water is 1: (0.12-0.18): (13-17);
the crystallization temperature is 120-126 ℃.
8. The strong permeability decoking agent for the boiler as claimed in claim 6, wherein the concentration of the silica sol is 30-36wt%;
in the mother liquor, the mol ratio of silicon dioxide, aluminum oxide, piperidine, sodium oxide and water is 1: (0.01-0.02): (0.2-0.3): (0.05-0.08): (25-30);
the addition amount of the seed crystal is 1-3% of the total amount of the mother liquor;
the crystallization temperature is 140-150 ℃;
the roasting temperature is 550-580 ℃.
9. The strong permeability decoking agent for the boiler as claimed in claim 1, wherein the preparation method of the decoking agent is as follows:
1) Weighing the raw material components according to the proportion for later use, adding tetrabutyl titanate and sodium fluoride into oleic acid, fully stirring at room temperature to obtain a reaction solution, adding a decoking catalyst into the reaction solution, transferring the reaction solution into a hydrothermal kettle, preserving heat for 23-26h at 200-210 ℃ after sealing, then adding deionized water into the hydrothermal kettle, packaging the hydrothermal kettle after stirring, preserving heat for 23-26h at 300-320 ℃, adding a product into ethanol after the reaction is finished, standing for 6-10h, repeatedly cleaning the obtained precipitate with ethanol, and drying to obtain a pretreatment decoking agent catalyst;
2) Pouring copper sulfate, magnesium nitrate, magnesium sulfate and potassium sulfate into a container, carrying out first round of stirring, adding a dispersing agent after the stirring is finished, carrying out second round of stirring, adding boric acid after the stirring is finished, slowly adding water during the stirring process, adding a pretreatment decoking agent catalyst after the stirring is finished, and standing for 1-2 hours after the stirring to obtain the required decoking agent.
10. The strong permeability decoking agent for the boiler as claimed in claim 9, wherein the dosage ratio of tetrabutyl titanate, sodium fluoride, oleic acid, deionized water and ethanol is (4.5-5.3) g: (0.05-0.07) g: (33-38) g: (1.5-2.0) g: (200-280) mL;
the mass ratio of the decoking catalyst to the reaction liquid is 1: (15-23).
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102766498A (en) * | 2012-08-13 | 2012-11-07 | 卢新宇 | Chemical catalyzing decoking agent |
| CN104910997A (en) * | 2015-06-01 | 2015-09-16 | 江苏燃顺环保科技有限公司 | Additive for clinker removal of coal-fired boilers and preparation method thereof |
| CN105695036A (en) * | 2016-02-26 | 2016-06-22 | 江苏燃顺环保科技有限公司 | Coal-fired boiler decoking agent and preparation method thereof |
| CN111253992A (en) * | 2018-11-30 | 2020-06-09 | 唐山市华亿生物质燃料有限公司 | Decoking agent and preparation method thereof |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102766498A (en) * | 2012-08-13 | 2012-11-07 | 卢新宇 | Chemical catalyzing decoking agent |
| CN104910997A (en) * | 2015-06-01 | 2015-09-16 | 江苏燃顺环保科技有限公司 | Additive for clinker removal of coal-fired boilers and preparation method thereof |
| CN105695036A (en) * | 2016-02-26 | 2016-06-22 | 江苏燃顺环保科技有限公司 | Coal-fired boiler decoking agent and preparation method thereof |
| CN111253992A (en) * | 2018-11-30 | 2020-06-09 | 唐山市华亿生物质燃料有限公司 | Decoking agent and preparation method thereof |
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