Preparation method of catalyst for decoking, dust removal and coal saving in coal-fired boilers

Abstract

The invention discloses a method for preparing a catalyst for decoking, dust removal, and coal saving in coal-fired boilers. The method comprises the following steps: preparing liquid A with water, sodium carbonate, boric acid, magnesium nitrate, and polyoxyethylene lanolin ether; preparing liquid B with water, strontium nitrate, samarium nitrate, zirconium nitrate, and magnesium chloride; uniformly mixing liquid A at 26-30% and liquid B at 62-66%, adding potassium nitrate at 3-5%, calcium nitrate at 2-4%, and calcein at 0.01-0.2%, stirring and dissolving, and adjusting the pH to between 4.5 and 7.0 with acid to obtain a yellow liquid catalyst for decoking, dust removal, and coal saving. The catalyst is added in an amount of 0.08-0.12% of the mass of the raw coal, and has the functions of preventing coking during combustion, removing coke, achieving a coal saving rate of 3-5%, and having excellent sulfur fixation and dust reduction effects, thereby significantly improving the combustion efficiency of coal.

Description

Technical Field

[0001] The present invention relates to an energy-saving, emission-reducing and decoking technology, and in particular to a preparation method of a decoking, dust-eliminating and coal-saving catalyst for a coal-fired boiler, belonging to the field of coal combustion technology. Background Art

[0002] Due to the scarcity and non-renewable nature of coal resources, power plant boilers are forced to burn low-quality coal with medium to low calorific value and low volatile matter, with low-volatile anthracite being the most prevalent. Due to the unique structure of these boilers and the complex causes of coking and slagging, coking is a potential problem. This is a long-term task requiring the continued efforts of various professionals and technicians to explore a fundamental solution to this problem.

[0003] Coking is a common problem in coal-fired boilers. Mild coking can reduce heat transfer efficiency and shorten the life of the boiler's heating surfaces. Severe coking can damage the heating surfaces and cause tube bursts, seriously impacting boiler safety and economic operation. Given the hazards of boiler coking, the development of effective decoking agents for coal-fired boilers is crucial.

[0004] Several common decoking agents currently on the market, while effective in removing coke, have several technical drawbacks. First, while these products are effective when using ordinary coal as a fuel, they are ineffective in preventing coking when the coal contains high levels of alkaline substances, particularly sodium and potassium. Second, these decoking agents often contain heavy metals (Cu), which can generate pollutants such as heavy metal aerosols during boiler combustion.

[0005] Coal combustion is a complex chemical reaction process, which can generally be divided into volatilization, combustion (homogeneous combustion) and ignition and combustion of carbon particles (heterogeneous combustion). The coal combustion process includes endothermic and exothermic reactions. The actual heat that can be utilized is equal to the heat released by coal combustion minus the activation energy required for coal combustion, that is, the heat required to reach the ignition point. If the activation energy required for coal to reach the ignition point can be reduced, it is equivalent to increasing the calorific value of coal, thereby reducing coal consumption in production. Decoking and coal-saving catalysts play the role of oxygen transfer and electron transfer in the coal combustion process, (1) changing the chemical reaction process of coal combustion, reducing the internal consumption of coal combustion, and making coal combustion easier. (2) reducing the cracking energy of large molecular organic compounds in coal to small molecular compounds during combustion, reducing the heat absorption in the cracking reaction. (3) The coal combustion mode is changed from outside to inside to "simultaneous combustion inside and outside". Through the synergistic effect of the penetrant and the expander, many microcracks are formed in the coal particles, which strengthens the rapid penetration of oxygen into the interior during the combustion process and releases oxygen internally, thereby achieving rapid combustion and concentrated heat release, increasing the temperature field temperature, making the temperature field uniform, and improving the fire intensity. (4) The coal is burned completely and the unburned coal rate is reduced. Chinese patent CN 102816625 A discloses a coal combustion promoter with good desulfurization effect, including a promoter and a desulfurizer, wherein the desulfurizer is methyl propiolate, and the methyl propiolate accounts for 1-2% of the total weight. The coal combustion saving rate of the present invention is significant, between 5-25%, and is particularly effective in promoting the combustion of low calorific value and low volatile coal. It can significantly reduce the sulfur content in the flue gas, with a reduction range of between 35-65%. Chinese patent CN101269339B discloses a coal-fired catalyst, which is prepared by mixing the following components in percentage by mass: 20-40% potassium salt, 10-25% industrial-grade sodium chloride, 15-30% quicklime, 9-15% bauxite, 1-4% rare earth oxide or rare earth chloride, and 0.1-1% ferric oxide. The coal-fired catalyst is obtained by uniformly mixing the above components; the sum of the mass percentages of the above components satisfies 100%. The potassium salt is a nitrate or a carbonate; the bauxite is obtained by directly crushing bauxite; and the ferric oxide is the trace amount of ferric oxide contained in the bauxite.

[0006] Most of the above existing technologies utilize the principle of oxygen-assisted combustion, typically using sodium chloride, potassium permanganate, sodium nitrate, magnesium chloride, potassium nitrate, potassium chlorate, and other raw materials as coal combustion aids. These are corrosive to boiler heating surfaces, reducing boiler lifespan. Furthermore, their functionality is limited, lacking dust removal, anti-coking, or catalysts. Most sulfur-fixing agents are organic, making them very expensive and prohibitive for manufacturers.

[0007] This application is a catalyst that can remove coke, prevent coking, eliminate dust, and save coal. It changes the chemical reaction of coal combustion, reduces heat loss caused by incomplete combustion in the chemical combustion process and incomplete mechanical combustion, reduces the emission of smoke and harmful gases in the exhaust gas, prevents coking and decoking in boilers, realizes the comprehensive utilization of coal, and reduces the overall cost of coal use. Summary of the Invention

[0008] One of the purposes of the present invention is to provide a method for preparing a catalyst for decoking, dust removal and coal saving in coal-fired boilers.

[0009] The purpose of the present invention is achieved through the following technical solutions.

[0010] A method for preparing a catalyst for decoking, dust removal and coal saving in a coal-fired boiler, characterized in that the method comprises the following process steps:

[0011] (1) Preparation of Solution A: In a reactor, add water (56-62%) and sodium carbonate (13-17%) according to the following mass percentage concentrations. After stirring and dissolving, slowly add boric acid (16-20%) and magnesium nitrate (4-8%). Stir and react for 8 hours. Add polyoxyethylene lanolin ether (1.0-2.0%). Adjust the pH to 6.5±0.2. The sum of all components is 100%. Stir and react for 2 hours to obtain Solution A.

[0012] (2) Preparation of Solution B: Add the following components in percentage by weight: water: 56-64%, strontium nitrate: 10-14%, samarium nitrate: 8-12%, zirconium nitrate: 8-12%, and magnesium chloride: 6-10% into a reactor, stir and dissolve until the sum of the components is 100%. After sufficient reaction, Solution B is obtained.

[0013] (3) Catalyst for decoking, dust elimination and coal saving: Add the following composition in mass percentage into the reactor: Liquid A: 26-30%, Liquid B: 62-66%, mix well, add potassium nitrate: 3-5%, calcium nitrate: 2-4%, calcein: 0.01-0.2%, stir and dissolve, adjust the pH to 4.5-7.0 with acid, and you will get a yellow liquid which is the catalyst for decoking, dust elimination and coal saving.

[0014] The molar ratio of sodium carbonate to boric acid in step (1) is greater than 1:2.

[0015] The mass ratio of samarium nitrate to zirconium nitrate in step (1) is 1:1.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] (1) The catalyst for decoking, dust removal and coal saving of a coal-fired boiler of the present invention is a stable yellow liquid that does not precipitate or stratify and does not freeze above -10°C;

[0018] (2) The operation is simple. It can be sprayed directly on the coal conveyor belt without changing the manufacturer's process equipment. The addition amount is 0.1% of the original coal amount.

[0019] (3) Decoking, coal saving and dust reduction, applicable to all kinds of coal, preventing coking during combustion, with a coal saving rate of 3-5%;

[0020] (4) Environmentally friendly, does not contain toxic heavy metals, does not produce heavy metal pollutants, and the production process does not emit three wastes;

[0021] (5) Easy to store and transport, simple and safe to operate, small addition amount, easily soluble in water, easy to use, and does not change the process equipment of the user unit;

[0022] (6) Safe and non-toxic, no harm to human body, ensuring the safety of operators. DETAILED DESCRIPTION

[0023] Example 1

[0024] (1) Preparation of Solution A: In a reactor, add 59 L of water and 15 kg of sodium carbonate, stir and dissolve, then slowly add 18 kg of boric acid and 6 kg of magnesium nitrate, stir and react for 8 h, add 2 kg of polyoxyethylene lanolin alcohol ether, adjust the pH to 6.5 ± 0.2, stir and react for 2 h, and obtain Solution A;

[0025] (2) Preparation of Solution B: In a reactor, add 60 L of water, 12 kg of strontium nitrate, 10 kg of samarium nitrate, 10 kg of zirconium nitrate, and 8 kg of magnesium chloride, stir and dissolve, and after sufficient reaction, obtain Solution B;

[0026] (3) Catalyst for decoking, dust elimination and coal saving: In a reactor, add 29 kg of liquid A and 64 kg of liquid B according to the following mass percentage concentrations, mix well, add 4 kg of potassium nitrate, 3 kg of calcium nitrate and 50 g of calcein, stir and dissolve, and adjust the pH to between 4.5 and 7.0 with acid to obtain a yellow liquid which is a catalyst for decoking, dust elimination and coal saving.

[0027] Example 2

[0028] (1) Preparation of Solution A: In a reactor, add 62 L of water and 13 kg of sodium carbonate, stir and dissolve, then slowly add 16 kg of boric acid and 8 kg of magnesium nitrate, stir and react for 8 h, add 1 kg of polyoxyethylene lanolin alcohol ether, adjust the pH to 6.5 ± 0.2, stir and react for 2 h, and obtain Solution A;

[0029] (2) Preparation of Solution B: In a reactor, add 56 L of water, 10 kg of strontium nitrate, 12 kg of samarium nitrate, 12 kg of zirconium nitrate, and 10 kg of magnesium chloride, stir and dissolve, and after sufficient reaction, obtain Solution B;

[0030] (3) Catalyst for decoking, dust elimination and coal saving: In a reactor, add 27 kg of liquid A and 66 kg of liquid B according to the following mass percentage concentrations, mix well, add 3 kg of potassium nitrate, 4 kg of calcium nitrate and 10 g of calcein, stir and dissolve, and adjust the pH to between 4.5 and 7.0 with acid to obtain a yellow liquid which is a catalyst for decoking, dust elimination and coal saving.

[0031] Example 3

[0032] (1) Preparation of Solution A: In a reactor, add 56 L of water and 17 kg of sodium carbonate, stir and dissolve, then slowly add 20 kg of boric acid and 5.5 kg of magnesium nitrate, stir and react for 8 h, and 1.5 kg of polyoxyethylene lanolin alcohol ether, adjust the pH to 6.5 ± 0.2, stir and react for 2 h to obtain Solution A;

[0033] (2) Preparation of Solution B: In a reactor, add 64 L of water, 14 kg of strontium nitrate, 8 kg of samarium nitrate, 8 kg of zirconium nitrate, and 6 kg of magnesium chloride, stir and dissolve, and after sufficient reaction, obtain Solution B;

[0034] (3) Catalyst for decoking, dust elimination and coal saving: In a reactor, add 28 kg of liquid A and 65 kg of liquid B according to the following mass percentage concentrations, mix well, add 5 kg of potassium nitrate, 2 kg of calcium nitrate and 60 g of calcein, stir and dissolve, and adjust the pH to between 4.5 and 7.0 with acid to obtain a yellow liquid which is a catalyst for decoking, dust elimination and coal saving.

[0035] Example 4

[0036] (1) Preparation of Solution A: In a reactor, add 60 L of water and 16 kg of sodium carbonate, stir and dissolve, then slowly add 17 kg of boric acid and 6 kg of magnesium nitrate, stir and react for 8 h, add 1 kg of polyoxyethylene lanolin alcohol ether, adjust the pH to 6.5 ± 0.2, stir and react for 2 h, and obtain Solution A;

[0037] (2) Preparation of Solution B: In a reactor, add 58 L of water, 13 kg of strontium nitrate, 11 kg of samarium nitrate, 11 kg of zirconium nitrate, and 7 kg of magnesium chloride, stir and dissolve, and after sufficient reaction, obtain Solution B;

[0038] (3) Catalyst for decoking, dust elimination and coal saving: In a reactor, add 30 kg of liquid A and 62 kg of liquid B according to the following mass percentage concentrations, mix well, add 4 kg of potassium nitrate, 4 kg of calcium nitrate and 40 g of calcein, stir and dissolve, and adjust the pH to between 4.5 and 7.0 with acid to obtain a yellow liquid which is a catalyst for decoking, dust elimination and coal saving.

[0039] Example 5

[0040] (1) Preparation of Solution A: In a reactor, add 58 L of water and 14 kg of sodium carbonate, stir and dissolve, then slowly add 19 kg of boric acid and 7 kg of magnesium nitrate, stir and react for 8 h, add 2 kg of polyoxyethylene lanolin alcohol ether, adjust the pH to 6.5 ± 0.2, stir and react for 2 h, and obtain Solution A;

[0041] (2) Preparation of Solution B: In a reactor, add 62 L of water, 11 kg of strontium nitrate, 9 kg of samarium nitrate, 9 kg of zirconium nitrate, and 9 kg of magnesium chloride, stir and dissolve, and after sufficient reaction, obtain Solution B;

[0042] (3) Catalyst for decoking, dust elimination and coal saving: In a reactor, add 26 kg of liquid A and 66 kg of liquid B according to the following mass percentage concentrations, mix well, add 5 kg of potassium nitrate, 3 kg of calcium nitrate and 200 g of calcein, stir and dissolve, and adjust the pH to between 4.5 and 7.0 with acid to obtain a yellow liquid which is a catalyst for decoking, dust elimination and coal saving.

[0043] Example 6

[0044] Usage: Dilute the decoking, dust removal, and coal-saving catalyst prepared in this invention 0-2 times with water. Use in pulverized coal furnaces without dilution. Use in circulating fluidized bed boilers with water. Spray the catalyst evenly on the coal before the coal mill in pulverized coal furnaces and before the pulverizer in circulating fluidized bed boilers. The amount of catalyst added should be 0.08-0.12% of the original coal mass.

[0045] The present invention obtains a decoking, dust-removing and coal-saving catalyst for coal-fired boilers, which is suitable for various coals, has the functions of preventing coking during combustion, removing coke, saving coal by 3-5%, and having good sulfur fixation and dust reduction effects, and significantly improving the combustion efficiency of coal.

Claims

1. A method for preparing a catalyst for decoking, dust removal and coal saving in coal-fired boilers, characterized in that: The method has the following process steps: (1) Preparation of Liquid A: In a reactor, add water (56-62%) and sodium carbonate (13-17%) according to the following mass percentage concentrations. After stirring and dissolving, slowly add boric acid (16-20%) and magnesium nitrate (4-8%). Stir and react for 8 h. Add polyoxyethylene lanolin ether (1.0-2.0%). Adjust the pH value to 6.5±0.

2. The sum of all components is 100%. Stir and react for 2 h to obtain Liquid A. (2) Preparation of Solution B: Add the following components by mass percentage into the reactor: water: 56-64%, strontium nitrate: 10-14%, samarium nitrate: 8-12%, zirconium nitrate: 8-12%, magnesium chloride: 6-10%, stir and dissolve until the sum of the components is 100%. After sufficient reaction, Solution B is obtained. (3) Catalyst for decoking, dust removal and coal saving of coal-fired boilers: Add the following composition in a reactor in mass percentage: liquid A: 26~30%, liquid B: 62~66%, mix well, add potassium nitrate: 3~5%, calcium nitrate: 2~4%, calcein: 0.01~0.2%, stir and dissolve, adjust the pH to between 4.5 and 7.0 with acid, and you will get the catalyst for decoking, dust removal and coal saving of coal-fired boilers.

2. The method for preparing a catalyst for decoking, dust removal and coal saving of a coal-fired boiler according to claim 1, characterized in that: The molar ratio of sodium carbonate to boric acid in step (1) is greater than 1:

2.

3. The method for preparing a catalyst for decoking, dust removal and coal saving of a coal-fired boiler according to claim 1, characterized in that: The mass ratio of samarium nitrate to zirconium nitrate in step (2) is 1:1.