Cerium sulfosalicylate for coal combustion catalyst, preparation method, catalyst and application

Abstract

This invention discloses a cerium sulfosalicylate sulfonate for use as a coal combustion catalyst, its preparation method, the catalyst itself, and its applications. The preparation method includes: S10, mixing cerium nitrate and sulfosalicylic acid dihydrate with water to obtain a cerium sulfosalicylate complex solution; S20, adding the cerium sulfosalicylate complex solution to a first reverse micelle solution to obtain a first mixed solution, then adding n-butanol in batches to obtain a first microemulsion; S30, adding ammonia to a second reverse micelle solution, then adding n-butanol in batches to obtain a second microemulsion; S40, mixing the first and second microemulsions and stirring to obtain a pale blue, opalescent colloidal solution, thus obtaining a second mixed solution; S50, drying and grinding the second mixed solution to obtain cerium sulfosalicylate. This cerium sulfosalicylate coal combustion catalyst is easily dispersed and can catalyze the pyrolysis and oxidation processes of coal from within, improving the utilization rate and calorific value of coal.

Description

Technical Field

[0001] This invention belongs to the field of fuel catalyst technology, specifically relating to a cerium sulfosalicylate for use in coal combustion catalysts, its preparation method, the catalyst, and its application. Background Technology

[0002] Existing coal-fired catalysts on the market have high production costs and limited coal-saving effects. There is an urgent need for a coal-fired catalyst that can save coal used in power generation, steel production, cement production, etc., and reduce emissions of carbon dioxide, sulfur dioxide, and nitrogen oxides. This catalyst would save coal-consuming enterprises money on raw coal procurement and rapidly achieve the energy-saving and emission-reduction goals of "carbon peaking and carbon neutrality" without changing the energy structure.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, this invention provides a cerium sulfosalicylate for use in coal combustion catalysts, its preparation method, the catalyst itself, and its applications. The technical problem to be solved by this invention is achieved through the following technical solution:

[0005] In a first aspect, the present invention provides a method for preparing cerium sulfosalicylate for use in coal combustion catalysts, comprising the following steps:

[0006] S10. Cerium nitrate and sulfosalicylic acid dihydrate are mixed with water and reacted to obtain a cerium sulfosalicylic acid complex solution; wherein the molar ratio of cerium nitrate to sulfosalicylic acid dihydrate is 1:(3-4);

[0007] S20. Obtain a first reverse micelle solution formed by hexadecyltrimethylammonium bromide and cyclohexane; add the cerium sulfosalicylate complex solution from step S10 to the first reverse micelle solution to obtain a milky white first mixed solution; wherein the molar ratio of the cerium sulfosalicylate complex to the hexadecyltrimethylammonium bromide is 1:(1-2);

[0008] S30. Add n-butanol to the first mixed solution in batches until the milky white first mixed solution is converted into a colorless and clear first microemulsion.

[0009] S40. Obtain a second reverse micelle solution formed by hexadecyltrimethylammonium bromide and cyclohexane;

[0010] Ammonia was added to the second reverse micelle solution, followed by n-butanol in batches until a colorless and clear second microemulsion was obtained.

[0011] S50. The first microemulsion and the second microemulsion are mixed and stirred until the mixed solution changes from colorless and transparent to a colloidal solution with a blue opalescent appearance, to obtain a second mixed solution; wherein the pH value of the second mixed solution is 4 to 5;

[0012] S60. The second mixed solution is dried and ground to obtain cerium sulfosalicylate for use in coal combustion catalysts.

[0013] In one embodiment of the present invention, in steps S20 and S40, the molar ratio of hexadecyltrimethylammonium bromide to cyclohexane in both the first and second reverse micelle solutions is 1:(7.5-8.5).

[0014] In one embodiment of the present invention, in step S10, the total mass ratio of the cerium nitrate and the dihydrate sulfosalicylic acid to the mass ratio of water is 1:(2-5).

[0015] In one embodiment of the present invention, the molar ratio of NH3 in the ammonia water to the cerium sulfosalicylate complex in the first microemulsion is (10-14):1.

[0016] In one embodiment of the present invention, step S60, the drying includes placing the second mixed solution in a vacuum drying oven and drying it at a temperature of 70-85°C for 20-30 hours to obtain a dried cerium sulfosalicylate solid block.

[0017] In one embodiment of the present invention, in step S60, the grinding includes placing the dried cerium sulfosalicylate solid block into an agate mortar and grinding in a clockwise or counterclockwise unidirectional circular motion along the inner wall of the mortar.

[0018] The ground powder is sieved through a standard sieve of 200-300 mesh.

[0019] Particles that fail to pass the sieve are returned to the agate mortar for further grinding until the dried cerium sulfosalicylate solid block is completely ground and sieved to obtain the cerium sulfosalicylate used as a coal combustion catalyst.

[0020] In a second aspect, the present invention provides cerium sulfosalicylate for use in coal combustion catalysts, wherein the cerium sulfosalicylate is prepared by the above-described preparation method;

[0021] The average particle size of the cerium sulfosalicylate ranges from 300 nm to 350 nm, and the particle size distribution index (PDI) is 0.25 to 0.35.

[0022] Thirdly, the present invention provides a coal combustion catalyst, comprising, by mass percentage, 50%–60% anhydrous calcium chloride, 30%–35% sodium chloride, 5%–10% sodium nitrate, 1%–3% anhydrous citric acid, and 0.5%–2% of the above-mentioned cerium sulfosalicylate.

[0023] Fourthly, the present invention provides an application of the above-mentioned coal-fired catalyst in the preparation of novel coal, the application comprising: mixing the coal-fired catalyst with raw coal at a mass ratio of (0.5-1):1000 to obtain novel coal.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. In the preparation method of cerium sulfosalicylate provided by the present invention, during the stirring and mixing process of the first microemulsion with a water core of cerium sulfosalicylate complex solution and the second microemulsion with a water core of ammonia solution, the micelles in the two microemulsions collide, fuse, and exchange substances. In the fused micelles formed, the cerium sulfosalicylate complex reacts with the ammonia solution (OH-). - It reacts with NH3. Because the reaction occurs in fused micelles, the precipitated cerium sulfosalicylate particles are small and uniform in size (e.g., in Example 1, the median particle size is 335 nm and the PDI is 0.34).

[0026] 2. The cerium sulfosalicylate nanoparticles provided by this invention are easier to uniformly disperse when used in pulverized coal, avoiding sedimentation and agglomeration caused by uneven catalyst particle size. This allows the pulverized coal to fully contact the catalyst, resulting in a more balanced and stable catalytic effect. Simultaneously, the nano-sized cerium sulfosalicylate catalyst particles can more easily penetrate into the micropores and fissures of the coal, catalyzing the pyrolysis and oxidation processes from within.

[0027] 3. The novel coal prepared by the cerium sulfosalicylate catalyst provided by this invention has high catalytic activity. It can simultaneously achieve the synergistic optimization of "impurity removal" (reduction of ash content and total sulfur content) and "quality improvement" (increase of volatile matter and increase of calorific value) without increasing "useless moisture" (no increase in total moisture). This provides a new high-activity catalyst option for improving the comprehensive performance and utilization rate of coal.

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0029] Figure 1 This is an X-ray diffraction characterization pattern of cerium sulfosalicylate prepared in Example 1 of this invention;

[0030] Figure 2 This is a schematic diagram of the particle size distribution of cerium sulfosalicylate prepared in Example 1 of the present invention;

[0031] Figure 3 This is a schematic diagram summarizing the particle size parameters of cerium sulfosalicylate prepared in Example 1 of the present invention.

[0032] Figure 4 This is a scanning electron microscope (SEM) characterization image (scale bar 20 μm) of cerium sulfosalicylate prepared in Example 1 of this invention.

[0033] Figure 5 This is a scanning electron microscope (SEM) characterization image of cerium sulfosalicylate prepared in Example 1 of this invention (scale bar 3 μm). Detailed Implementation

[0034] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following, in conjunction with the accompanying drawings and specific embodiments, provides a detailed description of a cerium sulfosalicylate for coal combustion catalysts, its preparation method, the catalyst, and its applications according to the present invention.

[0035] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and concrete understanding can be gained of the technical means and effects adopted by the present invention to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit the technical solutions of the present invention.

[0036] It should be noted that, in this document, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed.

[0037] This invention provides a cerium sulfosalicylate catalyst for use in coal combustion catalysts. The cerium sulfosalicylate catalyst has an average particle size ranging from 300 nm to 350 nm and a particle size distribution index (PDI) of 0.25 to 0.35. The cerium sulfosalicylate nanoparticles provided by this invention achieve more uniform dispersion when used in pulverized coal combustion, avoiding sedimentation and agglomeration caused by inconsistent catalyst particle sizes. This allows for sufficient contact between the pulverized coal and the catalyst, resulting in a more balanced and stable catalytic effect. Simultaneously, the nano-sized cerium sulfosalicylate catalyst particles can more easily penetrate the micropores and fissures of the coal, catalyzing the pyrolysis and oxidation processes from within.

[0038] The present invention also provides a method for preparing the above-mentioned cerium sulfosalicylate for coal combustion catalysts, the method comprising the following steps:

[0039] S10. Cerium nitrate and sulfosalicylic acid dihydrate are mixed with water and reacted to obtain a cerium sulfosalicylic acid complex solution; wherein the molar ratio of cerium nitrate to sulfosalicylic acid dihydrate is 1:(3-4).

[0040] In this embodiment, cerium nitrate (Ce(NO3)3) dissociates into Ce in aqueous solution. 3+ Ions. Sulfosalicylic acid dihydrate (C7H6O6S·2H2O) is a polydentate ligand whose carboxyl group (-COOH) and phenolic hydroxyl group (-OH) can deprotonate and react with Ce. 3+ Ion coordination occurs. The sulfosalicylate ion typically acts as a tripentate ligand; stoichiometrically, one Ce... 3+ The ions coordinate with the three sulfosalicylate ions to form a charge-balanced complex. Therefore, the molar amount of sulfosalicylic acid dihydrate should be at least three times the molar amount of cerium nitrate. In the preparation method provided by this invention, the excessive addition of sulfosalicylic acid dihydrate can, on the one hand, shift the reaction equilibrium to the right, ensuring that the key reactant (cerium nitrate) is completely consumed and converted, thereby increasing the precipitation rate (yield) of cerium; on the other hand, in the subsequent second microemulsion, the excess sulfosalicylic acid ligand can also adsorb onto the surface of the cerium sulfosalicylate particles, acting as a surface modifier to prevent particle aggregation and help control the particle size of the formed cerium sulfosalicylate.

[0041] For example, the molar ratio of cerium nitrate to sulfosalicylic acid dihydrate can be 1:3, 1:3.1, 1:3.2, 1:3.3, 1:3.4, 1:3.5, 1:3.6, 1:3.7, 1:3.8, 1:3.9 or 1:4.

[0042] In one example, in step S10, the mass ratio of cerium nitrate and sulfosalicylic acid dihydrate to water is 1:(2-5). It should be noted that in this example, if the amount of water is too low, both solids will not dissolve completely, resulting in a solution concentration that is too high and rapid supersaturation. This can lead to impurity inclusion or excessively rapid crystallization, affecting the quality of the final cerium sulfosalicylic acid solution. Conversely, if the amount of water is too high, the solution concentration may be too low, preventing the formation of an aqueous complex. For example, the mass ratio of cerium nitrate and sulfosalicylic acid dihydrate to water can be 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, or 1:5.

[0043] S20. Obtain a first reverse micelle solution formed by mixing hexadecyltrimethylammonium bromide and cyclohexane; add the cerium sulfosalicylate complex solution from step S10 to the first reverse micelle solution, stir evenly, and obtain a milky white first mixed solution; wherein, the molar ratio of cerium sulfosalicylate complex to hexadecyltrimethylammonium bromide is 1:(1~2).

[0044] S30. Add n-butanol to the first mixed solution in batches while stirring until the milky white first mixed solution turns into a colorless and clear first microemulsion.

[0045] In the embodiments provided by this invention, steps S20 and S30 are used to prepare a first microemulsion. Specifically, hexadecyltrimethylammonium bromide (CTAB), as a cationic surfactant, spontaneously forms first reverse micelles when dissolved in cyclohexane. These micelles have hydrophilic head groups (positively charged quaternary ammonium salt groups) facing inward and hydrophobic tails (hexadecyl chains) facing outward, dispersed in cyclohexane, and encapsulating tiny water cores inside. After adding a cerium sulfosalicylate complex solution to this first reverse micelle solution, the cerium sulfosalicylate complex solution is encapsulated by the first reverse micelles formed by hexadecyltrimethylammonium bromide, forming a W / O (water-in-oil) type white microemulsion. Adding n-butanol as a co-surfactant to this white microemulsion allows it to insert into the middle of hexadecyltrimethylammonium bromide molecules, further reducing the oil-water interfacial tension. By adding n-butanol in batches until the solution becomes colorless and clear, it indicates that a thermodynamically stable and uniformly sized first microemulsion system has been obtained. In this state, the tiny water cores all contain cerium sulfosalicylate complexes. In other words, the cerium sulfosalicylate complex is confined within the surfactant film formed by hexadecyltrimethylammonium bromide and n-butanol, thus restricting the subsequent reaction of the cerium sulfosalicylate complex to a "nanoreactor" formed by the surfactant film.

[0046] In this step, the molar ratio of cerium sulfosalicylate complex to hexadecyltrimethylammonium bromide is 1:(1-2). This is because if too little hexadecyltrimethylammonium bromide is used, a stable and uniform microemulsion cannot be formed, resulting in incomplete encapsulation of the cerium sulfosalicylate complex. This causes some of the cerium sulfosalicylate complex to leak into the oil phase (cyclohexane), thus losing its confinement function as a "nanoreactor." Conversely, if too much hexadecyltrimethylammonium bromide is used, although a stable microemulsion can be formed, the excess hexadecyltrimethylammonium bromide increases the viscosity of the solution system, thereby reducing the space for accommodating the cerium sulfosalicylate complex. Furthermore, excessive surfactant increases the difficulty and complexity of subsequent impurity removal processes.

[0047] In one example, in step S20, the molar ratio of hexadecyltrimethylammonium bromide to cyclohexane in the first reverse micelle solution formed by hexadecyltrimethylammonium bromide and cyclohexane is 1:(7.5–8.5). Within this range, the water cores in the formed reverse micelles are uniform in size, which facilitates the subsequent process of confining the reaction to water cores of uniform size to obtain nanoscale cerium sulfosalicylate with high size consistency.

[0048] S40. Obtain a second reverse micelle solution formed by mixing hexadecyltrimethylammonium bromide and cyclohexane; add ammonia to the second reverse micelle solution, mix well, and then add n-butanol in batches while stirring until a colorless and clear second microemulsion is obtained. In step S40, hexadecyltrimethylammonium bromide and cyclohexane are weighed again to prepare the second reverse micelle solution, and ammonia is added to the second reverse micelle solution to obtain a hexadecyltrimethylammonium bromide reverse micelle system containing an ammonia core; then n-butanol is added until a second microemulsion containing an ammonia core is obtained. That is, in the second microemulsion, the surfactant film formed by hexadecyltrimethylammonium bromide and n-butanol is coated with an ammonia solution.

[0049] In one example, in the second reverse micelle solution formed by hexadecyltrimethylammonium bromide and cyclohexane, the molar ratio of hexadecyltrimethylammonium bromide to cyclohexane is 1:(7.5–8.5). Within this range, the water cores in the formed reverse micelles are uniform in size, which facilitates the subsequent process of confining the reaction to water cores of uniform size to obtain nanoscale cerium sulfosalicylate with high size consistency.

[0050] S50. The first microemulsion and the second microemulsion are mixed and stirred until the mixed solution changes from colorless and transparent to a blue opalescent colloidal solution, obtaining the second mixed solution; wherein the pH value of the second mixed solution is 4-5. In this step, the first microemulsion (containing cerium sulfosalicylate complex) and the second microemulsion (containing ammonia solution) are mixed and stirred. The micelles in the two microemulsions collide, fuse, and exchange substances. In the fused micelles, the cerium sulfosalicylate complex in the water core of the first microemulsion reacts with the ammonia (OH-) in the water core of the second microemulsion. - The reaction occurs with NH3, and the reaction is confined within a fused nanoscale water core. The water cores formed based on hexadecyltrimethylammonium bromide and n-butanol exhibit uniform size, and the resulting cerium sulfosalicylate particles also demonstrate high uniformity. The pale blue opalescent colloidal solution indicates the formation of colloidal particles; the pale blue opalescence is a typical Tyndall effect, indicating the formation of nanoparticles with sizes between 1 and 100 nm in the solution. These particles scatter light (Rayleigh scattering, with stronger scattering of shorter wavelengths of blue light).

[0051] This embodiment employs a dual microemulsion method to prepare cerium sulfosalicylate. Both the cerium sulfosalicylate complex and ammonia are encapsulated within multiple nanoscale "water nuclei." When the first and second microemulsions are mixed and the microemulsion droplets begin to collide, the reaction completes within a very small, confined space. This ensures that all particles have almost identical nucleation sites and a consistent growth environment, thus preventing explosive nucleation and rapid particle growth caused by localized supersaturation, and improving the uniformity of the prepared cerium sulfosalicylate particles. Furthermore, the pH value needs to be adjusted during the mixing and reaction of the first and second microemulsions. The dual microemulsion method provides a relatively closed and stable reaction environment, thereby increasing the synthesis success rate.

[0052] In one example, the molar ratio of NH3 in the ammonia solution to the cerium sulfosalicylate complex in the first microemulsion is (10-14):1. In the second mixed solution, the pH is adjusted to 4-5 using ammonia. In the reaction of step S50, ammonia can act as a pH adjuster to deprotonate sulfosalicylate, reduce supersaturation, and promote the complete precipitation of cerium sulfosalicylate nanoparticles. If the amount of ammonia is too small, the pH is too low, and the sulfosalicylate cannot be completely deprotonated, resulting in a low yield of cerium sulfosalicylate or even failure to obtain the target product. If the amount of ammonia is too large, the pH is too high, and Ce... 3+ It is very easy to hydrolyze under alkaline conditions, forming a cerium hydroxide gel precipitate, which makes it impossible to obtain cerium sulfosalicylate.

[0053] S60. The second mixed solution is dried and ground to obtain cerium sulfosalicylate for use in coal-fired catalysts.

[0054] In one example, drying involves placing the second mixed solution in a vacuum drying oven and drying it at a temperature of 70–85°C for 20–30 hours to obtain a dried solid block of cerium sulfosalicylate.

[0055] In one example, grinding includes placing the dried solid block of cerium sulfosalicylate into an agate mortar and grinding it in a single direction, either clockwise or counterclockwise, along the inner wall of the mortar; sieving the ground powder through a standard sieve of 200-300 mesh; returning any particles that fail to pass through the sieve to the agate mortar for further grinding until the dried solid block of cerium sulfosalicylate is completely ground and sieved to obtain cerium sulfosalicylate for use as a coal combustion catalyst.

[0056] This invention also provides a coal-fired catalyst, which, by mass percentage, comprises 50%–60% anhydrous calcium chloride, 30%–35% sodium chloride, 5%–10% sodium nitrate, 1%–3% anhydrous citric acid, and 0.5%–2% cerium sulfosalicylate prepared in any of the above embodiments.

[0057] This invention also provides an application of the above-mentioned coal-fired catalyst in the preparation of novel coal, comprising: mixing the above-mentioned coal-fired catalyst with raw coal at a mass ratio of (0.5-1):1000 to obtain novel coal.

[0058] The following specific embodiments further illustrate the preparation method and application of cerium sulfosalicylate for coal-fired catalysts provided by the present invention.

[0059] Example 1

[0060] S10. Mix 0.05 mol (22 g) cerium nitrate, 200 g (11.1 mol) deionized water, and 0.175 mol (44.5 g) sulfosalicylic acid dihydrate to obtain a cerium sulfosalicylic acid complex solution.

[0061] S20. Weigh 0.075 mol of hexadecyltrimethylammonium bromide, dissolve it in 0.60 mol of cyclohexane, add the cerium sulfosalicylate complex solution obtained in step S10, and stir to obtain a first mixed solution. The first mixed solution is a milky white opaque emulsion.

[0062] S30. Add n-butanol dropwise to the first mixed solution until the solution system changes from a milky white opaque emulsion to a colorless, clear, and stable microemulsion to obtain the first microemulsion.

[0063] S40. Weigh 0.075 mol of cetyltrimethylammonium bromide (CTAB), dissolve it in 0.60 mol of cyclohexane, add 2 g of ammonia water (of which 0.6 mol of NH3), stir well, and then add n-butanol dropwise until the system changes from a milky white emulsion to a colorless, clear, and stable microemulsion to obtain the second microemulsion.

[0064] S50. The first microemulsion and the second microemulsion are rapidly mixed. Stirring allows the system to be observed to change from colorless and transparent to a pale blue opalescent colloidal solution, thus obtaining the second mixed solution.

[0065] S60. The second mixed solution is dried at 70–85°C for 20–30 hours. The dried cerium sulfosalicylate solid block is placed in an agate mortar and ground in a clockwise circular motion along the inner wall of the mortar. The ground powder is then sieved through a 250-mesh standard sieve. Particles that fail to pass through the sieve are returned to the agate mortar for further grinding until the cerium sulfosalicylate solid block is completely ground and sieved, thus obtaining cerium sulfosalicylate for use as a coal combustion catalyst. The cerium sulfosalicylate prepared in this embodiment is defined as cerium sulfosalicylate 1.

[0066] The cerium sulfosalicylate 1 prepared in Example 1 was tested:

[0067] 1. For example Figure 1The figure shows a comparative X-ray diffraction (XRD) characterization of cerium sulfosalicylate 1 and sulfosalicylic acid prepared in Example 1. As can be seen from the figure, the characteristic diffraction peaks of cerium sulfosalicylate at diffraction angles (2θ) of 14.78°, 16.86°, 20.77°, 25.76°, 29.20°, 41.07°, 42.25°, and 51.93° correspond to the characteristic peaks of the standard spectrum of sulfosalicylic acid; among them, the diffraction peak near 27.89° corresponds to the Ce(111) crystal plane. The above diffraction peak positions and their combinations indicate that the prepared substance is cerium sulfosalicylate.

[0068] 2. For example Figure 2 and Figure 3 The diagram shows the particle size measurement results of cerium sulfosalicylate 1 prepared in Example 1. The results indicate that the cerium sulfosalicylate particle size D90 obtained by the preparation method provided by this invention is 360 nm, indicating that the particle size of 90% cerium sulfosalicylate is less than 360 nm, and the median D50 is 278 nm, indicating that the particle size of 50% cerium sulfosalicylate is less than 278 nm. Furthermore, the polydispersity index (PDI) of cerium sulfosalicylate particle size is 0.34, indicating that the particle size distribution of cerium sulfosalicylate is narrow and its uniformity is good.

[0069] 3. For example Figure 4 and Figure 5 The image shown is a scanning electron microscope (SEM) image of cerium sulfosalicylate 1 prepared in Example 1. As can be seen from the image, the prepared cerium sulfosalicylate is mostly rectangular in shape and has good dispersibility.

[0070] Example 2

[0071] The difference between this embodiment and Example 1 is as follows: In step S10, cerium nitrate is 0.05 mol, deionized water is 6.7 mol, and sulfosalicylic acid dihydrate is 0.15 mol; in step S20, hexadecyltrimethylammonium bromide is 0.10 mol and cyclohexane is 0.75 mol; in step S40, hexadecyltrimethylammonium bromide is 0.10 mol, cyclohexane is 0.75 mol, and NH3 is 0.5 mol.

[0072] The remaining operations were the same as in Example 1. The cerium sulfosalicylate obtained in Example 2 was defined as cerium sulfosalicylate 2. The morphology and particle size of the electron micrographs of cerium sulfosalicylate 2 were similar to those of cerium sulfosalicylate 1.

[0073] Example 3

[0074] The difference between this embodiment and Example 1 is as follows: In step S10, cerium nitrate is 0.05 mol, deionized water is 8.3 mol, and sulfosalicylic acid dihydrate is 0.20 mol; in step S20, hexadecyltrimethylammonium bromide is 0.05 mol and cyclohexane is 0.425 mol; in step S40, hexadecyltrimethylammonium bromide is 0.05 mol, cyclohexane is 0.425 mol, and NH3 is 0.7 mol.

[0075] The remaining operations were the same as in Example 1. The cerium sulfosalicylate obtained in Example 3 was defined as cerium sulfosalicylate 3. The morphology and particle size of the electron micrograph of cerium sulfosalicylate 3 were similar to those of cerium sulfosalicylate 1.

[0076] Example 4

[0077] The difference between this embodiment and Example 1 is as follows: In step S10, cerium nitrate is 0.05 mol, deionized water is 20.0 mol, and sulfosalicylic acid dihydrate is 0.20 mol; in step S20, hexadecyltrimethylammonium bromide is 0.05 mol and cyclohexane is 0.40 mol; in step S40, hexadecyltrimethylammonium bromide is 0.05 mol, cyclohexane is 0.4 mol, and NH3 is 0.5 mol.

[0078] The remaining operations were the same as in Example 1. The cerium sulfosalicylate prepared in Example 4 was defined as cerium sulfosalicylate 4. The morphology and particle size of the electron micrograph of cerium sulfosalicylate 4 were similar to those of cerium sulfosalicylate 1.

[0079] Example 5

[0080] The difference between this embodiment and Example 1 is as follows: In step S10, cerium nitrate is 0.05 mol, deionized water is 16.7 mol, and sulfosalicylic acid dihydrate is 0.175 mol; in step S20, hexadecyltrimethylammonium bromide is 0.075 mol, and cyclohexane is 0.56 mol; in step S40, hexadecyltrimethylammonium bromide is 0.075 mol, cyclohexane is 0.56 mol, and NH3 is 0.6 mol.

[0081] The remaining operations were the same as in Example 1. The cerium sulfosalicylate obtained in Example 5 was defined as cerium sulfosalicylate 5. The morphology and particle size of the electron micrograph of cerium sulfosalicylate 5 were similar to those of cerium sulfosalicylate 1.

[0082] Example 6

[0083] A coal-fired catalyst was prepared using cerium sulfosalicylate 1 obtained in Example 1.

[0084] A coal-fired catalyst was prepared by mixing 56% anhydrous calcium chloride, 32% sodium chloride, 8% sodium nitrate, 3% anhydrous citric acid, and 1% cerium sulfosalicylate, according to weight percentage. This coal-fired catalyst is defined as coal-fired catalyst 1.

[0085] Example 7

[0086] A coal-fired catalyst was prepared using cerium sulfosalicylate 1 obtained in Example 1.

[0087] A coal-fired catalyst was prepared by mixing 52% anhydrous calcium chloride, 35% sodium chloride, 10% sodium nitrate, 1% anhydrous citric acid, and 2% cerium sulfosalicylate according to weight percentage. This coal-fired catalyst is defined as coal-fired catalyst 2.

[0088] Example 8

[0089] A coal-fired catalyst was prepared using cerium sulfosalicylate 1 obtained in Example 1.

[0090] A coal-fired catalyst was prepared by mixing 60% anhydrous calcium chloride, 30% sodium chloride, 7.5% sodium nitrate, 2% anhydrous citric acid, and 0.5% cerium sulfosalicylate by weight percentage. This coal-fired catalyst is defined as coal-fired catalyst 3.

[0091] Example 9

[0092] A coal-fired catalyst was prepared using cerium sulfosalicylate 1 obtained in Example 1.

[0093] A coal-fired catalyst was prepared by mixing 50% anhydrous calcium chloride, 35% sodium chloride, 10% sodium nitrate, 3% anhydrous citric acid, and 2% cerium sulfosalicylate, according to weight percentage. This coal-fired catalyst is defined as coal-fired catalyst 4.

[0094] Example 10

[0095] A coal-fired catalyst was prepared using cerium sulfosalicylate obtained in Example 1.

[0096] A coal-fired catalyst was prepared by mixing 56% anhydrous calcium chloride, 35% sodium chloride, 5% sodium nitrate, 3% anhydrous citric acid, and 1% cerium sulfosalicylate, according to weight percentage. This coal-fired catalyst is defined as coal-fired catalyst 5.

[0097] Example 11

[0098] A coal-fired catalyst was prepared using cerium sulfosalicylate obtained in Example 1.

[0099] A coal-fired catalyst was prepared by mixing 53% anhydrous calcium chloride, 35% sodium chloride, 10% sodium nitrate, 1.5% anhydrous citric acid, and 0.5% cerium sulfosalicylate by weight percentage. This coal-fired catalyst is defined as coal-fired catalyst 6.

[0100] Example 12

[0101] The coal-fired catalyst 1 prepared in Example 6 was mixed with bituminous coal to obtain a bituminous coal mixture; wherein, the mass of coal-fired catalyst 1 in the bituminous coal mixture was 0.5 g, and the mass of bituminous coal was 1000 g. The bituminous coal mixture was placed in a ball mill and ball-milled at 500 rpm for 10 minutes to obtain test sample No. 1.

[0102] Example 13

[0103] The coal-fired catalyst 1 prepared in Example 6 was mixed with bituminous coal to obtain a bituminous coal mixture; wherein, the mass of coal-fired catalyst 1 in the bituminous coal mixture was 1g and the mass of bituminous coal was 1000g. The bituminous coal mixture was placed in a ball mill and ball-milled at 500rpm for 10 minutes to obtain test sample No. 2.

[0104] Example 14

[0105] The coal-fired catalyst 2 prepared in Example 7 was mixed with bituminous coal to obtain a bituminous coal mixture; wherein, the mass of coal-fired catalyst 2 in the bituminous coal mixture was 1g and the mass of bituminous coal was 1000g. The bituminous coal mixture was placed in a ball mill and ball-milled at 500rpm for 10 minutes to obtain test sample No. 3.

[0106] Example 15

[0107] The coal-fired catalyst 1 prepared in Example 6 was mixed with anthracite to obtain an anthracite mixture; wherein, the mass of coal-fired catalyst 1 in the anthracite mixture was 1g and the mass of anthracite was 1000g. The anthracite mixture was placed in a ball mill and ball-milled at 500rpm for 10 minutes to obtain test sample No. 4.

[0108] Example 16

[0109] The coal-fired catalyst 2 prepared in Example 7 was mixed with anthracite to obtain an anthracite mixture; wherein, the mass of coal-fired catalyst 2 in the anthracite mixture was 1g and the mass of anthracite was 1000g. The anthracite mixture was placed in a ball mill and ball-milled at 500rpm for 10 minutes to obtain test sample No. 5.

[0110] Example 17

[0111] The coal-fired catalyst 1 prepared in Example 6 was mixed with lignite to obtain a lignite mixture; wherein, the mass of coal-fired catalyst 1 in the lignite mixture was 0.5 g, and the mass of lignite was 1000 g. The lignite mixture was placed in a ball mill and ball-milled at 500 rpm for 10 minutes to obtain test sample No. 6.

[0112] Example 18

[0113] The coal-fired catalyst 1 prepared in Example 6 was mixed with lignite to obtain a lignite mixture; wherein, the mass of coal-fired catalyst 1 in the lignite mixture was 1g and the mass of lignite was 1000g. The lignite mixture was placed in a ball mill and ball-milled at 500rpm for 10 minutes to obtain test sample No. 7.

[0114] Example 19

[0115] The coal-fired catalyst 2 prepared in Example 7 was mixed with lignite to obtain a lignite mixture; wherein, the mass of coal-fired catalyst 2 in the lignite mixture was 1g and the mass of lignite was 1000g. The lignite mixture was placed in a ball mill and ball-milled at 500rpm for 10 minutes to obtain test sample No. 8.

[0116] Comparative Example 1

[0117] Take 1000g of bituminous coal, place it in a ball mill, and ball mill it at 500rpm for 10 minutes to obtain control sample No. 1.

[0118] Comparative Example 2

[0119] Take 1000g of anthracite and place it in a ball mill. Mill it at 500rpm for 10 minutes to obtain control sample No. 2.

[0120] Comparative Example 3

[0121] Take 1000g of lignite, place it in a ball mill, and ball mill it at 500rpm for 10 minutes to obtain control sample No. 3.

[0122] 100g of each of the test samples 1 to 8 and control samples 1 to 3 were taken and subjected to industrial analysis and calorific value determination of the coal samples according to Chinese national standards GB / T211-2017, GB / T212-2008, GB / T214-2007 and GB / T213-2008, respectively, to detect the total moisture (Mt), ash content (A), volatile matter (V), total sulfur (St) and calorific value (Q) of each sample. The results are shown in Table 1.

[0123] Table 1. Measurement results for each sample

[0124]

[0125] The measurement results in Table 1 show that:

[0126] (1) Increased moisture content in coal samples reduces effective calorific value, increases transportation costs, affects crushing and slurry (coal-water slurry) performance, and also reduces furnace temperature due to vaporization and heat absorption during combustion. In this embodiment of the invention, adding a coal-fired catalyst to bituminous coal, anthracite, or lignite does not increase the total moisture content of the sample. In other words, adding a catalyst does not affect the moisture content of the coal sample.

[0127] (2) The ash content of a coal sample refers to the non-combustible solid residue remaining after the coal sample is completely burned under the conditions specified in the Chinese national standard. It is mainly derived from the high-temperature conversion of minerals in the coal. The higher the ash content, the less combustible material in the coal, resulting in incomplete combustion, reduced thermal efficiency, and a higher likelihood of unburned particles. The total sulfur content of a coal sample is the sum of all forms of sulfur (organic sulfur, inorganic sulfur, and elemental sulfur) in the coal sample. The higher the total sulfur content, the more sulfur is converted into gases such as sulfur dioxide and sulfur trioxide during combustion, which will cause environmental pollution. According to the test results in Table 1, the test results of test samples 1, 2, and 3 obtained by mixing bituminous coal with a coal-fired catalyst were compared with the test sample 1. The test results of test samples 4 and 5 obtained by mixing anthracite with a coal-fired catalyst were compared with the test sample 2. The test results of test samples 6, 7, and 8 obtained by mixing lignite with a coal-fired catalyst were compared with the test sample 3. All showed a decrease in ash content and a reduction in total sulfur. This indicates that the coal-fired catalyst provided by the present invention, when mixed with bituminous coal (or anthracite, lignite), can promote more complete combustion of the coal sample and reduce the polluting gases generated during combustion.

[0128] (3) The volatile matter content of a coal sample is the mass percentage of gaseous and liquid products (such as tar) produced by the pyrolysis of coal under high temperature and air-isolated conditions. The higher the volatile matter content, the higher the flammability, the lower the ignition temperature, and the higher the reactivity. The calorific value of coal is the core indicator for measuring the energy content of coal, and its level directly reflects the combustion efficiency and economic value of coal. As shown in Table 1, the test results of test samples No. 1, No. 2, and No. 3 obtained by mixing bituminous coal with a coal-fired catalyst and the test results of control sample No. 1, the test results of test samples No. 4 and No. 5 obtained by mixing anthracite with a coal-fired catalyst and the test results of control sample No. 2, and the test results of test samples No. 6, No. 7, and No. 8 obtained by mixing lignite with a coal-fired catalyst and the test results of control sample No. 3 all show an increase in volatile matter and an increase in calorific value. Thus, the results in Table 1 show that when the coal-fired catalyst provided by this invention is mixed with bituminous coal (or anthracite, lignite), it has a catalytic activation effect, increasing volatile matter and making the coal with the added catalyst easier to ignite and burn more rapidly and completely, which is particularly beneficial for improving the utilization of low-reactivity coal types (e.g., anthracite). On the other hand, it increases the calorific value, thereby increasing the energy density of the coal sample with the added coal-fired catalyst.

[0129] (4) In the test samples No. 1 to No. 3 prepared in Examples 12, 13 and 14, the content of cerium sulfosalicylate in the coal-fired catalyst showed an increasing trend. In the corresponding test results, the ash content and total sulfur showed a decreasing trend, while the volatile matter and calorific value showed an increasing trend. This indicates that the performance improvement of bituminous coal is dose-dependent on the amount of coal-fired catalyst added.

[0130] Referring to test samples No. 4 to No. 5 prepared in Examples 15 and 16, the content of cerium sulfosalicylate in the coal-fired catalyst showed an increasing trend. In the corresponding test results, the ash content and total sulfur showed a decreasing trend, while the volatile matter and calorific value showed an increasing trend. This indicates that the performance improvement of anthracite is dose-dependent on the amount of coal-fired catalyst added.

[0131] Referring to test samples 6 through 8 prepared in Examples 17, 18, and 19, the content of cerium sulfosalicylate in the coal-fired catalyst showed an increasing trend. Correspondingly, the ash content and total sulfur showed a decreasing trend, while the volatile matter and calorific value showed an increasing trend. This indicates a dose-dependent relationship between the performance improvement of lignite and the amount of coal-fired catalyst added. Therefore, increasing the amount of coal-fired catalyst (or cerium sulfosalicylate) leads to a corresponding increase in the performance of the raw coal. Considering both the performance and cost of the coal, the coal-fired catalyst provided by this invention, when mixed with raw coal at a mass ratio of (0.5–1):1000, can improve the overall performance of the raw coal without increasing the total cost.

[0132] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing cerium sulfosalicylate for use in coal combustion catalysts, characterized in that, Includes the following steps: S10. Cerium nitrate and sulfosalicylic acid dihydrate are mixed with water and reacted to obtain a cerium sulfosalicylic acid complex solution; wherein the molar ratio of cerium nitrate to sulfosalicylic acid dihydrate is 1:(3-4); S20. Obtain a first reverse micelle solution formed by hexadecyltrimethylammonium bromide and cyclohexane; add the cerium sulfosalicylate complex solution from step S10 to the first reverse micelle solution to obtain a milky white first mixed solution; wherein the molar ratio of the cerium sulfosalicylate complex to the hexadecyltrimethylammonium bromide is 1:(1-2); S30. Add n-butanol to the first mixed solution in batches until the milky white first mixed solution is converted into a colorless and clear first microemulsion. S40. Obtain a second reverse micelle solution formed by hexadecyltrimethylammonium bromide and cyclohexane; Ammonia was added to the second reverse micelle solution, and then n-butanol was added in batches until a colorless and clear second microemulsion was obtained; the molar ratio of NH3 in the ammonia to the cerium sulfosalicylate complex in the first microemulsion was (10-14):1; In both the first and second reverse micelle solutions, the molar ratio of hexadecyltrimethylammonium bromide to cyclohexane is 1:(7.5-8.5). S50. The first microemulsion and the second microemulsion are mixed and stirred until the mixed solution changes from colorless and transparent to a colloidal solution with a blue opalescent appearance, to obtain a second mixed solution; wherein the pH value of the second mixed solution is 4 to 5; S60. The second mixed solution is dried and ground to obtain cerium sulfosalicylate for use in coal combustion catalysts; the average particle size of the cerium sulfosalicylate is between 300 nm and 350 nm, and the particle size distribution index (PDI) is between 0.25 and 0.

35.

2. The method for preparing cerium sulfosalicylate for coal combustion catalysts according to claim 1, characterized in that, In step S10, the total mass ratio of cerium nitrate and sulfosalicylic acid dihydrate to water is 1:(2-5).

3. The method for preparing cerium sulfosalicylate for coal combustion catalysts according to claim 1, characterized in that, In step S60, the drying process includes placing the second mixed solution in a vacuum drying oven and drying it at a temperature of 70–85°C for 20–30 hours to obtain a dried solid block of cerium sulfosalicylate.

4. The method for preparing cerium sulfosalicylate for coal combustion catalysts according to claim 3, characterized in that, In step S60, the grinding includes placing the dried cerium sulfosalicylate solid block into an agate mortar and grinding it in a single direction, either clockwise or counterclockwise, along the inner wall of the mortar. The ground powder is sieved through a standard sieve of 200-300 mesh. Particles that fail to pass the sieve are returned to the agate mortar for further grinding until the dried cerium sulfosalicylate solid block is completely ground and sieved to obtain cerium sulfosalicylate for use as a coal-fired catalyst.

5. A coal combustion catalyst, characterized in that, The product comprises, by mass percentage, 50%–60% anhydrous calcium chloride, 30%–35% sodium chloride, 5%–10% sodium nitrate, 1%–3% anhydrous citric acid, and 1%–2% cerium sulfosalicylate obtained by the preparation method according to any one of claims 1–4.

6. The application of the coal-fired catalyst according to claim 5 in the preparation of coal, characterized in that, include: The coal-fired catalyst is mixed with raw coal at a mass ratio of (0.5-1):1000 to obtain coal.

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