Molecular sieve catalytic slag melting agent for molten slag discharge of high-iron coal

Abstract

A molecular sieve catalytic slag melting agent for high-iron coal liquid slag removal comprises 10-20 parts of a loosening and expanding agent, 10-20 parts of a molecular sieve catalyst and 30-60 parts of a fluxing reducing agent, and has the beneficial effects that the loosening and expanding agent can crack and expand ash; vanadium anhydride added in the fluxing reducing agent can promote generation of low-temperature eutectic substances in the ash residues when the mass fraction is lower than 5%. And further, under the action of the molecular sieve catalyst enhanced reaction, the fluxing reducing agent can enhance the reducing atmosphere, promote the conversion of ferric iron in the slag body to ferrous iron, reduce the melting point of an iron-containing compound, promote the conversion of the solid slag body at the slag discharge port to low-melting-point liquid-phase flow slag, and ensure that ash in the furnace is smoothly discharged out of the furnace body. Through reasonable preparation, the slag melting agent developed by the invention can realize fluidization of slag at a slag discharge port within a temperature range of 900 DEG C, avoids unplanned furnace shutdown or safety problems caused by slag blockage, and also can realize the effect of replacing the existing natural gas heating fluxing anti-slag-blocking technology.

Description

Technical Field

[0001] The present invention relates to the field of slag discharge of gasifiers, and specifically relates to a molecular sieve catalytic slag melting agent for high-iron coal liquid slag discharge. Background Art

[0002] The Zhundong coalfield is located in the eastern part of the Junggar Basin in Xinjiang, with a predicted reserve of 390 billion tons. Coupled with open-pit mining, it has significant cost advantages as commercial thermal coal. However, some coal resources in the Zhundong area of Xinjiang have a high Fe element content, which is extremely likely to cause slagging and fouling problems on the heating surface during the gasification process.

[0003] Iron mainly exists in raw coal in the forms of FeO, Fe2O3, FeS, and FeS2, etc. During the coal gasification process, it is transformed into iron-containing aluminosilicate substances, and is significantly affected by gas components (CO / CO2 / O2 / H2), chemical composition, and temperature. Fe 3+ has strong polarity and is difficult to react with other minerals. The ash melting temperature in an oxidizing atmosphere is as high as 1565 °C. While gases such as CO and H2 have strong reducibility, Fe2O3 in the ash is reduced to ferrous iron Fe 2+ , and its melting temperature decreases.

[0004] In a liquid slag discharge gasifier burning high-iron coal, slagging and ash accumulation are likely to occur at the slag discharge outlet due to temperature reduction. In severe cases, it will even cause slag blockage in the gasifier. The slag layer with a high iron content has a high hardness, and it is not easy to dredge after slag blockage occurs. The gasifier needs to be shut down unexpectedly, resulting in serious economic losses. Currently, mainly by burning natural gas to increase the temperature at the slag discharge outlet, melting the solid slag at the slag discharge outlet, and discharging the slag in a liquid form, the cost is high, resulting in a certain degree of resource waste and economic burden.

[0005] In the invention patent application with the publication number CN117568075A and the name of a liquid coke removal agent for a waste incinerator and its preparation method, a method of microexplosion and chemical reaction after the liquid is in full contact with the coke block is disclosed, which makes the coke block fragmented and improves the coke removal efficiency. This method is mainly applicable to highly viscous slag with high adhesiveness, and has an insignificant effect on the commonly occurring slag with high hardness in a high-iron coal gasifier. Summary of the Invention

[0006] To solve the defect that the existing liquid slag discharge gasifier burning high-iron coal usually wastes energy by increasing the temperature of the slag discharge port, the purpose of the present invention is to provide a molecular sieve catalytic slag melting agent for high-iron coal liquid slag discharge.

[0007] To achieve the above object, the present invention adopts the following technical solution: A molecular sieve catalytic slagging agent for high-speed railway coal liquid slag discharge, comprising 10-20 parts of a loose expanding agent, 10-20 parts of a molecular sieve catalyst, and 30-60 parts of a flux reducing agent.

[0008] Further, the loose expanding agent comprises sodium bicarbonate.

[0009] Further, the molecular sieve catalyst comprises fly ash, hydrochloric acid, sodium hydroxide, silicon dioxide, tetrapropylammonium hydroxide, cerium nitrate hexahydrate, and borax.

[0010] Further, the flux reducing agent comprises vanadium anhydride, carbon powder, sodium acetate, and sodium carbonate.

[0011] The present invention also provides a preparation method of a molecular sieve catalytic slagging agent for high-speed railway coal liquid slag discharge, comprising the following steps: Grind the sodium bicarbonate to below 48 µm to obtain the loose expanding agent.

[0012] Roast the fly ash in a muffle furnace at 500 °C for 6 h. After cooling, take 3 g and add it to 20 ml of hydrochloric acid with a concentration of 2 mol / L, stir at 30 °C for 2 h, filter, wash the collected fly ash with deionized water until neutral, dry it at 110 °C for 10 h, mix the pretreated fly ash and sodium hydroxide according to a mass ratio of 1-1.2 and grind, roast at 680 °C for 3 h, cool to room temperature and then crush and grind again.

[0013] Take 10 g of the above-treated fly ash, add 30 ml of deionized water, stir for 2 h, add silicon dioxide and tetrapropylammonium hydroxide (TPAOH), with a molar ratio of n(H2O):n(SiO2):n(TPAOH)=50:1:(0.3-0.5), stir for 2 h and then transfer to a hydrothermal reaction kettle, crystallize in an oven at 180 °C for 48 h, take out and cool after the reaction, filter, wash with deionized water, and dry at 110 °C for 12 h to obtain the molecular sieve.

[0014] Weigh 1 g of cerium nitrate hexahydrate, add 30 ml of deionized water, stir at room temperature for 10 min, add 4-5 g of the molecular sieve for impregnation, stir at room temperature for 4 h, dry at 110 °C for 10 h and then roast in a muffle furnace for 3 h to obtain the supported molecular sieve.

[0015] Add borax to the supported molecular sieve with a mass ratio of (1-1.5):(2-3), and grind thoroughly to below 48 µm to obtain the molecular sieve catalyst.

[0016] Mix the vanadium anhydride, carbon powder, sodium acetate and sodium carbonate in a molar ratio of (1 - 2.5):(1 - 2):(2 - 3):(10 - 15), and grind them to below 48 µm to obtain a flux reducing agent.

[0017] Stir and mix the loose expander, molecular sieve catalyst, and flux reducing agent evenly, and dry them at 110 °C for 120 min to obtain a molecular sieve catalytic slag agent for the liquid slag removal of high-iron coal.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: ① In the present invention, sodium bicarbonate is used as the loose expander, which can chemically react with inorganic minerals in the slag, causing the slag to expand, increasing internal pores, and enlarging pore sizes, which helps the molecular sieve catalyst and flux reducing agent to enter the slag.

[0019] ② In the present invention, in order to promote the slag melting effect and reduce costs, fly ash is modified successively with hydrochloric acid and sodium hydroxide to dissolve silicon and aluminum, destroy its quartz and mullite structures, and release amorphous SiO2 and Al2O3, thereby activating the silicon and aluminum in the fly ash; silica is used as the silicon source to adjust the silicon-aluminum ratio, and tetrapropylammonium hydroxide is used as the template agent. After loading cerium nitrate, a molecular sieve is prepared; the loaded molecular sieve has a porous structure with pore diameters concentrated in the range of 2 nm - 5 nm. During the combustion process, cerium nitrate is released and acts as a flux to change the network structure of aluminosilicate in the slag, thereby destroying the continuity of the network structure, reducing the viscosity of the slag, facilitating smooth slag removal, and improving the gasification efficiency; borax is added to the loaded catalyst to promote the melting of metal oxides such as Fe2O3 in the furnace, form a eutectic at low temperature, and enhance the fluidity of the slag, thereby promoting the liquid slag removal effect.

[0020] ③ In the present invention, in order to promote the melting of high-iron ash slag, a certain proportion of vanadium anhydride is added. When the mass fraction of vanadium anhydride is lower than 5%, it can usually interfere with the crystallization process of high-iron ash slag. By adsorbing on the surface of crystal nuclei or changing the crystal growth direction, it inhibits crystal formation and maintains the liquid characteristics of the slag. To further enhance the slag melting effect, carbon powder is added as a reducing agent. In a reducing atmosphere, Fe 3+ is transformed into Fe 2+ , the crystallization temperature decreases, and the viscosity also decreases, which is beneficial to the smooth discharge of iron-containing minerals. Sodium ions in sodium acetate enter the lattice structure of the slag, destroying the lattice stability of the original high-melting-point substances in the slag, forming low-melting-point sodium salts, which play a role in fluxing. Sodium carbonate reacts with acidic oxides (such as SiO2, Al2O3, etc.) in the slag to form more stable silicate compounds, making the slag properties more stable and maintaining good liquid slag removal performance in complex chemical processes. Specific embodiments

[0021] The various exemplary embodiments of the present invention will be described in detail below. This detailed description should not be construed as a limitation on the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0022] In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0023] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0024] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are merely exemplary.

[0025] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0026] In the examples of the present invention, the "parts" mentioned are all in parts by mass.

[0027] The present invention will be further described in detail below with reference to specific examples. Examples

[0028] A molecular sieve catalytic slagging agent for high-speed railway coal liquid slag discharge comprises the following raw materials: 20 parts of a loose expanding agent, 20 parts of a molecular sieve catalyst, and 60 parts of a flux reducing agent.

[0029] A preparation method of a molecular sieve catalytic slagging agent for high-speed railway coal liquid slag discharge comprises the following steps: mixing the loose expanding agent, the molecular sieve catalyst, and the flux reducing agent evenly by stirring, and drying at 110°C for 120 min to obtain a molecular sieve catalytic slagging agent for high-speed railway coal liquid slag discharge. Example

[0030] A molecular sieve catalytic slag flux for high-speed rail coal liquid slagging, comprising the following raw materials: 20 parts of a loose expanding agent, 15 parts of a molecular sieve catalyst, and 60 parts of a flux reducing agent.

[0031] The preparation method of a molecular sieve catalytic slag flux for high-speed rail coal liquid slagging is the same as that of Example 1. Example

[0032] A molecular sieve catalytic slag flux for high-speed rail coal liquid slagging, comprising the following raw materials: 15 parts of a loose expanding agent, 20 parts of a molecular sieve catalyst, and 48 parts of a flux reducing agent.

[0033] The preparation method of a molecular sieve catalytic slag flux for high-speed rail coal liquid slagging is the same as that of Example 1.

[0034] Comparative Example 1 A molecular sieve catalytic slag flux for high-speed rail coal liquid slagging, differing from Example 1 in that the flux reducing agent is 50 parts.

[0035] The remaining raw materials are the same as those in Example 1.

[0036] The preparation method of a molecular sieve catalytic slag flux for high-speed rail coal liquid slagging is the same as that of Example 1.

[0037] Comparative Example 2 A molecular sieve catalytic slag flux for high-speed rail coal liquid slagging, differing from Example 2 in that the loose expanding agent is 15 parts.

[0038] The remaining raw materials are the same as those in Example 2.

[0039] The preparation method of a molecular sieve catalytic slag flux for high-speed rail coal liquid slagging is the same as that of Example 1.

[0040] Performance Test The molecular sieve catalytic slag fluxes for high-speed rail coal liquid slagging prepared in the above Examples 1-3 and Comparative Examples 1-2 were sprayed into the slag discharge outlet of the gasifier for performance testing, and the test results are shown in Table 1. As mentioned above, the above are only the preferred specific embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A molecular sieve catalytic slagging agent for high-speed railway coal liquid slag removal comprises a loose expander, a molecular sieve catalyst, and a fluxing reducing agent.

2. The molecular sieve catalytic slagging agent for high-speed rail coal liquid slag discharge according to claim 1, wherein The mass parts of the raw materials are as follows: 10 - 20 parts of the loose expander, 10 - 20 parts of the molecular sieve catalyst, and 30 - 60 parts of the fluxing reducing agent.

3. A molecular sieve catalytic slagging agent for high-speed rail coal liquid slag discharge according to claim 1, characterized in that The loose expander includes sodium bicarbonate.

4. A molecular sieve catalytic slagging agent for high-speed railway coal liquid slagging according to claim 1, characterized in that The molecular sieve catalyst includes fly ash, hydrochloric acid, sodium hydroxide, silicon dioxide, tetrapropylammonium hydroxide, cerium nitrate hexahydrate, and borax.

5. The molecular sieve catalytic slagging agent for high-speed rail coal liquid slag discharge according to claim 1, wherein The fluxing reducing agent includes vanadic anhydride, carbon powder, sodium acetate, and sodium carbonate.

6. The molecular sieve catalytic slagging agent for high-speed railway coal liquid slag discharge according to claim 1, characterized in that Adjust the ratio of the loose expander, the molecular sieve catalyst, and the fluxing reducing agent according to the gasification raw materials and the properties of the slag.

7. A preparation method of a molecular sieve catalytic slag flux for high-speed railway coal liquid slagging, comprising a molecular sieve catalytic slag flux for high-speed railway coal liquid slagging according to any one of claims 1-6, characterized in that, It includes the following steps: S1: Raw material selection, treatment, and weighing: Select the required raw materials of the loose expander, the molecular sieve catalyst, and the fluxing reducing agent in the required weight ratio, grind and screen various raw materials, and then place them separately inside the storage tank; S2: Making the molecular sieve catalyst: Roast fly ash in a muffle furnace at 500 °C for 6 h. After cooling, take 3 g and add it to 20 ml of hydrochloric acid with a concentration of 2 mol / L, stir at 30 °C for 2 h, filter, wash the collected fly ash with deionized water until neutral, dry it at 110 °C for 10 h, mix and grind the pretreated fly ash and sodium hydroxide according to a mass ratio of 1 - 1.2, roast at 680 °C for 3 h, cool to room temperature, and then crush and grind again to obtain the pretreated fly ash; S3: Take 10 g of the pretreated fly ash, add 30 ml of deionized water, stir for 2 h, add silicon dioxide and tetrapropylammonium hydroxide (TPAOH), with a molar ratio of n(H2O):n(SiO2):n(TPAOH)=50:1:(0.3 - 0.5), stir for 2 h and then transfer to a hydrothermal reaction kettle, crystallize in an oven at 180 °C for 48 h, take out and cool after the reaction, filter, wash with deionized water, and dry at 110 °C for 12 h to obtain the molecular sieve; S4: Weigh 1 g of cerium nitrate hexahydrate, add 30 ml of deionized water, stir at room temperature for 10 min, add 4 - 5 g of the molecular sieve for impregnation, oscillate and stir at room temperature, dry at 110 °C for 10 h and then roast in a muffle furnace for 3 h to obtain the supported molecular sieve; S5: Add borax to the supported molecular sieve with a mass ratio of (1 - 1.5):(2 - 3), and grind thoroughly to below 48 µm to obtain the molecular sieve catalyst; S6: Making the fluxing reducing agent: Thoroughly mix vanadic anhydride, carbon powder, sodium acetate, and sodium carbonate according to a molar ratio of (1 - 2.5):(1 - 2):(2 - 3):(10 - 15) and then grind to below 48 µm to obtain the fluxing reducing agent; S7: Stir and mix the loose expander, the molecular sieve catalyst obtained in S5, and the fluxing reducing agent obtained in S6 evenly, dry at 110 °C for 120 min to obtain a molecular sieve catalytic slagging agent for high-speed railway coal liquid slag removal.

8. The molecular sieve catalytic slagging agent for high-speed railway coal liquid slag discharge according to claim 7, characterized in that The output power of the oscillation device in S4 is 300 - 400 W, and the ultrasonic oscillation time is 4 - 5 h.