Aviation kerosene desulfurizer and preparation method thereof

Abstract

This invention discloses a method for preparing an aviation kerosene desulfurizer, relating to the field of aviation fuel desulfurization technology, aiming to overcome the technical defects of existing desulfurizers, such as poor dispersibility of active components, unstable pore structure, and low sulfur capacity. The method includes: dissolving soluble copper salt, zinc salt, and nickel salt in deionized water at a specific molar ratio to prepare a mixed metal salt solution; adding hydrotalcite powder, sodium alginate, and polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer to the mixed metal salt solution and stirring to obtain a mixed slurry; drying and crushing the mixed slurry, then aging it in an atmosphere with a water vapor partial pressure of 0.1-0.3 MPa; and finally calcining it at 400-550℃, sieving to collect the particles, thus obtaining the desulfurizer. This invention, through the synergistic effect of the active components, carrier precursor, dispersant, and structure-directing agent, combined with aging treatment under a specific atmosphere, can enhance the desulfurization accuracy, sulfur capacity, and regeneration stability of the desulfurizer.

Description

Technical Field

[0001] This invention relates to the technical field of desulfurization treatment. More specifically, this invention relates to an aviation kerosene desulfurizing agent and its preparation method. Background Technology

[0002] Aviation kerosene, as the dedicated fuel for aircraft turbine engines, directly affects flight safety and engine lifespan. With the rapid development of the aviation industry and increasingly stringent environmental regulations, extremely stringent requirements have been placed on the sulfur content of aviation kerosene. During combustion, sulfides not only generate sulfur oxides (SOx) that corrode high-temperature engine components, but also increase particulate matter emissions in the exhaust gas and promote the formation of secondary fine particulate matter in the aircraft engine exhaust. Furthermore, sulfides reduce fuel lubricity, affecting the stable operation of the fuel system. Therefore, deep removal of sulfides from aviation kerosene has become a key technological step in ensuring the clean utilization of aviation fuel.

[0003] Currently, the mainstream desulfurization technologies for aviation kerosene in industry mainly include hydrodesulfurization and adsorption desulfurization. While hydrodesulfurization can effectively remove sulfides, it suffers from drawbacks such as demanding process conditions, high hydrogen consumption, high operating costs, and the potential for hydrogen saturation of unsaturated hydrocarbons, thus affecting fuel calorific value. Adsorption desulfurization, due to its ability to operate under ambient temperature and pressure or relatively mild conditions, without consuming hydrogen, and offering high desulfurization precision, is considered a highly promising non-hydrogenation deep desulfurization technology. The core of adsorption desulfurization lies in the development of high-performance desulfurizing agents. Existing desulfurizing agents are mostly based on metal oxides or supported metal sulfides, achieving desulfurization through chemical adsorption or coordination between the active component and the sulfide. However, traditional desulfurizing agents generally suffer from poor dispersion of active components, easy pore blockage, low sulfur capacity, and poor regeneration stability. Especially when processing aviation kerosene systems containing various complex sulfides, the selective adsorption capacity of desulfurizing agents for sulfur-containing compounds with different structures, such as thiophenes and sulfides, is insufficient, making it difficult to consistently meet the production requirements of ultra-low sulfur fuels. In addition, the bonding strength between the active component and the carrier in the existing preparation process is limited, and the active component is prone to loss during use, which affects the lifespan and recycling performance of the desulfurizer.

[0004] Therefore, it is necessary to design a technical solution that can overcome the above-mentioned defects. Summary of the Invention

[0005] One object of the present invention is to provide an aviation kerosene desulfurizing agent and its preparation method, so as to enhance the desulfurization accuracy, sulfur capacity and regeneration stability of the desulfurizing agent.

[0006] To achieve these objectives and other advantages of the present invention, according to one aspect of the present invention, a method for preparing an aviation kerosene desulfurizer is provided, comprising: S1: dissolving a soluble copper salt, a soluble zinc salt, and a soluble nickel salt in deionized water to prepare a mixed metal salt solution, wherein the molar ratio of copper ions, zinc ions, and nickel ions is 1:(1.2-1.8):(0.3-0.8), and the molar concentration of total metal ions in the mixed metal salt solution is 0.9-1.4. S2: Add hydrotalcite powder, sodium alginate, and polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer to a mixed metal salt solution, wherein the mass ratio of sodium alginate to hydrotalcite powder is (0.05-0.2):1, and the mass ratio of polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer to sodium alginate is (0.5-1.5):1. Mix under stirring at 60-80℃ to obtain a mixed slurry; S3: Dry the mixed slurry at 80-100℃ to obtain a dried product; S4: Crush the dried product to obtain crushed particles; S5: Place the crushed particles in an atmosphere with a water vapor partial pressure of 0.1-0.3 MPa and age them at 120-180℃ to obtain an aged product; S6: Age the aged product at 400-550℃. S7: The roasted product is obtained by roasting at ℃; S8: The roasted product is sieved and particles with a particle size range of 20-60 mesh are collected to obtain aviation kerosene desulfurizer.

[0007] Further, in step S2, sodium alginate is added to the mixed metal salt solution and mixed at 60-70°C for 15-30 minutes under stirring to obtain a first mixture; hydrotalcite powder is added to the first mixture and mixed at 60-70°C for 30-60 minutes under stirring to obtain a second mixture; polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer is added to the second mixture and mixed at 60-80°C for 60-120 minutes under shear stirring to obtain a mixed slurry; wherein, the mass ratio of the mixed metal salt solution to the total mass of sodium alginate, hydrotalcite powder, and polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer is (10-20):1.

[0008] Further, the polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer is prepared by the following steps: polyethylene glycol and polypropylene glycol are mixed at a molar ratio of 1:(2-4), heated to 80-100 °C under a nitrogen atmosphere, a catalyst is added (toluenesulfonic acid), and the amount of catalyst added is 0.5-5% of the total mass of polyethylene glycol and polypropylene glycol. The mixture is stirred for 2-4 hours to obtain a first intermediate; the first intermediate is cooled to 40-50 °C, ethylene oxide is added, and the molar ratio of ethylene oxide to polypropylene glycol units in the first intermediate is (2-4):1. The mixture is reacted at a pressure of 0.2-0.4 MPa for 3-6 hours to obtain a second intermediate; the second intermediate is cooled to room temperature, washed with deionized water, allowed to stand and separate into layers, and the organic phase is taken. The organic phase is vacuum dried at 60-80 °C for 4-8 hours to obtain the polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer.

[0009] Further, the mixed slurry is placed in a vacuum drying oven, and under a vacuum of 0.06-0.09 MPa, the temperature is increased from room temperature to 50-60 ℃ at a heating rate of 1-3 ℃ / min, and dried at a constant temperature for 2-4 hours. Then, the temperature is increased to 80-100 ℃ at a heating rate of 0.5-1.5 ℃ / min, and dried at a constant temperature for 6-10 hours to obtain the dried product.

[0010] Further, in S4, the dried product is placed in a jaw crusher for coarse crushing, so that the particle size of the coarsely crushed material is less than 5 mm. The coarsely crushed material is passed through a 10-mesh sieve, and the oversize material is collected and returned to the jaw crusher for coarse crushing again. The undersize material is collected and placed in a roller crusher for fine crushing, so that the particle size of the finely crushed material is less than 1 mm. The finely crushed material is passed through a 20-mesh sieve, and the oversize material is collected and returned to the roller crusher for fine crushing again. The undersize material is collected as crushed particles.

[0011] Further, in step S5, the crushed particles are placed in a high-pressure reactor, and a mixture of water vapor and carbon dioxide is introduced into the reactor, controlling the volume ratio of water vapor to carbon dioxide to be (2-5):1. The total pressure inside the high-pressure reactor is adjusted to 0.3-0.8 MPa, so that the partial pressure of water vapor reaches 0.1-0.3 MPa. The temperature is increased from room temperature to 80-100℃ at a heating rate of 1-3℃ / min, and aged at a constant temperature for 1-2 hours. Then, the temperature is increased to 120-180℃ at a heating rate of 0.5-1.5℃ / min, and aged at a constant temperature for 3-6 hours to obtain an intermediate aged product. The intermediate aged product is cooled to 40-60℃ in a nitrogen atmosphere, depressurized, and then placed in an oven to dry at 60-80℃ for 2-4 hours to obtain the aged product.

[0012] Further, in S6, the aging product is placed in a tube furnace and heated to 200-250 ℃ at a heating rate of 2-5 ℃ / min. It is then calcined at a constant temperature in air for 1-2 hours. After stopping the air supply, the vacuum is evacuated to a vacuum degree of 0.09-0.095 MPa. Nitrogen gas is then introduced to atmospheric pressure, and the temperature is further increased to 400-550 ℃ at a heating rate of 1-3 ℃ / min. The product is then calcined at a constant temperature in nitrogen for 2-4 hours to obtain the calcined product.

[0013] According to another aspect of the invention, an aviation kerosene desulfurizer is also provided.

[0014] The present invention has at least the following beneficial effects: This invention effectively improves the adsorption performance and structural stability of desulfurizers by precisely controlling the molar ratio of three active metal ions—copper, zinc, and nickel—and combining the synergistic effects of hydrotalcite powder, sodium alginate, and polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer. The introduction of sodium alginate and the triblock copolymer creates a steric hindrance effect in the mixed slurry, significantly inhibiting the agglomeration of metal ions during drying and calcination. This results in a highly dispersed state of the active components in the desulfurizer, thereby greatly improving the utilization rate of active sites and enhancing the selective adsorption capacity for thiophene sulfides in aviation kerosene. Hydrotalcite, as a carrier precursor, forms a layered composite metal oxide after calcination. This not only provides abundant mesoporous channels, facilitating the diffusion and mass transfer of sulfide molecules, but also modulates the electronic properties of the active centers through the synergistic doping of zinc and nickel, enhancing desulfurization activity and sulfur capacity. This invention employs an aging treatment under water vapor partial pressure control, which promotes the regularization of the pore structure in the desulfurizer precursor and strengthens the interaction between the active component and the carrier, effectively inhibiting the loss of active components during use and significantly improving the cycle regeneration stability of the desulfurizer.

[0015] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0016] Figure 1 This is a flowchart of one embodiment of this application. Detailed Implementation

[0017] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0018] It should be understood that terms such as "having," "comprising," and "including" used in the embodiments of this application do not exclude the presence or addition of one or more other elements or combinations thereof. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. When an element is referred to as "fixed to" or "set on" another element, it can be directly on the other element or may have an intervening element present. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element through an intervening element. Descriptions involving "first," "second," etc., in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0019] It should be noted that the technical solutions of the various embodiments of this application can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this application.

[0020] In one embodiment, when preparing an aviation kerosene desulfurizer, soluble copper salt, soluble zinc salt, and soluble nickel salt are first dissolved in deionized water to prepare a mixed metal salt solution. The soluble copper salt can be copper nitrate or copper sulfate, the soluble zinc salt can be zinc nitrate or zinc sulfate, and the soluble nickel salt can be nickel nitrate or nickel sulfate. These salts have good solubility in water and can provide the required metal ions. The molar ratio of copper ions, zinc ions, and nickel ions can be controlled at 1:1.5:0.5, or alternatively 1:1.2:0.3 or 1:1.8:0.8. This ratio aims to form multi-metal oxide active centers in the final desulfurizer. The total molar concentration of metal ions in the mixed metal salt solution can be set to 1.2 mol / L, or other values ​​between 0.9 mol / L and 1.4 mol / L. This concentration ensures an appropriate total amount of active components during subsequent loading. Next, hydrotalcite powder, sodium alginate, and polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer are added to the mixed metal salt solution. Hydrotalcite powder, as a carrier precursor, contributes to mesoporous formation through its layered structure; sodium alginate, as a natural polymer, acts as a dispersant and binder; and the triblock copolymer acts as a structure-directing and dispersant. The mass ratio of sodium alginate to hydrotalcite powder can be controlled at 0.1:1, or other ratios between 0.05:1 and 0.2:1; the mass ratio of the triblock copolymer to sodium alginate can be controlled at 1:1, or other ratios between 0.5:1 and 1.5:1. Under stirring conditions, the mixture is heated to 70°C, or alternatively 60°C or 80°C, to ensure thorough mixing of the components and the formation of a homogeneous slurry. This mixing step is performed by a stirring device; the input is the raw materials, the output is a homogeneous slurry, and the trigger condition is reaching the set temperature and maintaining stirring. Subsequently, the mixed slurry is dried at 90°C, or alternatively at 80°C or 100°C, to remove free moisture and obtain a dried product. The dried product is then crushed, for example, using mechanical crushing equipment to produce crushed particles. These crushed particles are placed in an atmosphere with a water vapor partial pressure of 0.2 MPa, or alternatively 0.1 MPa or 0.3 MPa, and aged at 150°C, or alternatively 120°C or 180°C. This process, through the action of water vapor, promotes precursor structural reorganization and enhances the interaction between the active component and the carrier. After aging, the product is calcined at 480°C, or alternatively 400°C or 550°C, to decompose the metal salt into metal oxides and form a stable crystalline phase structure, obtaining a calcined product. Finally, the calcined product is sieved, collecting particles with a particle size range of 20 to 60 mesh. This particle size distribution ensures good packing performance and fluid distribution characteristics of the desulfurizer in a fixed-bed reactor, thus obtaining an aviation kerosene desulfurizer.

[0021] In existing technologies, the preparation of aviation kerosene desulfurizers often employs an impregnation method to load active metals onto a single oxide carrier. This method suffers from problems such as uneven distribution of active components, easy agglomeration, and easy clogging of the pore structure. This embodiment addresses these issues by pre-preparing solutions of three active metal ions—copper, zinc, and nickel—and simultaneously introducing hydrotalcite powder, sodium alginate, and a triblock copolymer for mixing. This allows for more uniform dispersion of metal ions on the carrier surface and between layers in the slurry. The thickening and dispersing effects of sodium alginate, combined with the steric hindrance effect of the triblock copolymer, effectively inhibit the migration and agglomeration of metal ions during drying and subsequent heat treatment. Furthermore, aging under specific water vapor partial pressure further modulates the pore structure of the desulfurizer precursor, resulting in a tighter bond between the active components and the carrier. Compared to traditional preparation methods, the desulfurizer prepared in this embodiment exhibits superior performance in terms of active component dispersion uniformity, pore structure regularity, and structural stability.

[0022] In one embodiment, a step-by-step addition and staged mixing method is used when preparing the mixed slurry. First, sodium alginate is added to the mixed metal salt solution and mixed at 65°C for 20 minutes under stirring, or alternatively at 60°C or 70°C for 15 to 30 minutes, to ensure the sodium alginate is fully dissolved and uniformly dispersed, forming a first mixture. The addition of sodium alginate at this stage allows its molecular chains to initially coordinate with the metal ions in the solution, stabilizing them. Next, hydrotalcite powder is added to the first mixture and mixed at 65°C for 45 minutes under stirring, or alternatively at 60°C or 70°C for 30 to 60 minutes, to allow the hydrotalcite powder to fully adsorb the metal ions and form a uniform suspension system, resulting in a second mixture. The layered structure of hydrotalcite at this stage can capture some of the metal ions, achieving pre-loading of the active component. Finally, the polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer is added to the second mixture and mixed at 70°C for 90 minutes under shear stirring conditions. Alternatively, it can be mixed at 60°C or 80°C for 60 to 120 minutes to obtain a mixed slurry. Shear stirring provides strong shear force, promoting the formation of micelle structures in the triblock copolymer within the system, which act as steric hindrance and prevent particle agglomeration during subsequent processing. The mass ratio of the mixed metal salt solution to the total mass of sodium alginate, hydrotalcite powder, and triblock copolymer can be controlled at 15:1, or alternatively 10:1 or 20:1. This ratio ensures that the liquid phase is sufficient to fully wet and disperse the solid components, forming a slurry system with a suitable solid content, facilitating subsequent drying and molding operations.

[0023] This embodiment employs a step-by-step feeding method. First, sodium alginate is used to stabilize the metal ions. Then, hydrotalcite is introduced for loading, and finally, a triblock copolymer is added for spatial stabilization. Each step is optimized for specific interfacial interactions. This sequential feeding method, combined with the stirring conditions at each stage, results in a more orderly and uniform distribution of the active components on the carrier. Simultaneously, the introduction of shear stirring further enhances the dispersion effect of the system. Compared to existing processes that involve one-time mixing, this embodiment, through precise control of the feeding sequence and mixing conditions, obtains a higher-quality mixed slurry, laying the foundation for the subsequent preparation of highly dispersible desulfurizers.

[0024] In one embodiment, the polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer is prepared by the following steps: Polyethylene glycol and polypropylene glycol are mixed at a molar ratio of 1:3, or alternatively 1:2 or 1:4. The mixture is heated to 90°C, or alternatively 80°C or 100°C, under a nitrogen atmosphere. Toluenesulfonic acid is added as a catalyst at 2% (0.5% or 5%) of the total mass of polyethylene glycol and polypropylene glycol. The mixture is reacted under stirring for 3 hours, or alternatively 2 hours or 4 hours, to induce esterification and obtain the first intermediate. In this step, toluenesulfonic acid acts as an acidic catalyst, promoting the condensation reaction between polyethylene glycol and polypropylene glycol. The first intermediate is cooled to 45°C, or alternatively 40°C or 50°C, and ethylene oxide is added. The molar ratio of ethylene oxide to the polypropylene glycol units in the first intermediate can be controlled at 3:1, or alternatively 2:1 or 4:1. The reaction is carried out at a pressure of 0.3 MPa for 4 hours, or alternatively 0.2 MPa or 0.4 MPa for 3 to 6 hours, allowing ethylene oxide to undergo ring-opening polymerization and graft onto both ends of the first intermediate, forming a triblock structure to obtain the second intermediate. This reaction is carried out under pressure to improve the solubility of ethylene oxide in the liquid phase and the reaction rate. The second intermediate is cooled to room temperature and washed with deionized water to remove residual catalyst and unreacted monomers. After standing and separating into layers, the organic phase is collected and vacuum-dried at 70°C for 6 hours, or alternatively 60°C or 80°C for 4 to 8 hours, to remove moisture and low-boiling substances, yielding a polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer. This triblock copolymer, acting as a structure directing agent, can form micelles in aqueous solution during the preparation of desulfurizing agents, thereby regulating the pore structure and spatial dispersion.

[0025] This embodiment utilizes a self-made triblock copolymer, allowing for flexible adjustment of the polyethylene glycol (PEG) and polypropylene glycol (PPG) segment ratios to better suit the hydrophilic-lipophilic balance of the copolymer within a mixed system of copper, zinc, and nickel ions. This adjustability enables the copolymer to more effectively form stable micelle structures in the mixed slurry, thereby maximizing its steric hindrance effect during subsequent drying and calcination, and inhibiting the aggregation of active components. Compared to directly using commercially available products, the copolymer prepared in this embodiment exhibits stronger compatibility with desulfurizing agent systems.

[0026] In one embodiment, the mixed slurry is placed in a vacuum drying oven for staged drying. First, the vacuum level is set to 0.08 MPa, or alternatively 0.06 MPa or 0.09 MPa, and the temperature is increased from room temperature to 55°C, or alternatively 50°C or 60°C, at a rate of 2°C per minute, and then dried at this constant temperature for 3 hours, or alternatively 2 hours or 4 hours. This stage is carried out under relatively low temperature and vacuum conditions, primarily to slowly remove free water from the slurry and prevent the collapse of the pore structure or migration of active components due to rapid water evaporation. Subsequently, the temperature is increased to 90°C, or alternatively 80°C or 100°C, at a rate of 1°C per minute, or alternatively 0.5°C per minute or 1.5°C per minute, and then dried at this constant temperature for 8 hours, or alternatively 6 hours or 10 hours, to further remove bound water and allow for more complete interaction between sodium alginate and metal ions, forming a stable network structure to obtain the dried product. The main actuator for this segmented drying process is a vacuum drying chamber. The input consists of a mixed slurry and a preset drying program, and the output is a uniformly structured dried product. The trigger condition is that heating begins once the vacuum level reaches a set value. By controlling the heating rate and drying temperature, the surface morphology and internal pore structure of the dried product can be effectively controlled, preventing cracking or surface crusting caused by excessively rapid drying.

[0027] This embodiment employs segmented vacuum drying. The vacuum environment lowers the boiling point of water, allowing drying to proceed at a lower temperature. Combined with slow heating, this provides ample time for moisture to migrate from the interior to the surface. This drying method effectively avoids the problem of active components accumulating on the surface due to rapid moisture migration, enabling metal ions to be more uniformly fixed within the carrier. This improves the overall uniformity of the distribution of active components, reduces surface crusting, and creates favorable conditions for subsequent calcination to form a uniform active phase.

[0028] In one embodiment, the dried product is coarsely crushed in a jaw crusher to achieve a particle size of less than 5 mm. The coarsely crushed material is then sieved through a 10-mesh screen. The oversize material (particles larger than the 10-mesh screen opening) is collected and returned to the jaw crusher for further coarse crushing. The undersize material (particles smaller than the 10-mesh screen opening) is collected and placed in a roller crusher for further fine crushing to achieve a particle size of less than 1 mm. The finely crushed material is then sieved through a 20-mesh screen. The oversize material is collected and returned to the roller crusher for further fine crushing, while the undersize material is collected as the crushed particles. The crushing process is executed sequentially by a jaw crusher and a roller crusher. The input is the dried, lumpy material, and the output is crushed particles with a uniform particle size distribution. The jaw crusher is suitable for the initial crushing of large materials, and its working gap can be adjusted to 5 mm to ensure the consistency of the material size after coarse crushing. The roller crusher is suitable for further fine crushing, and its roller gap can be adjusted to 1 mm, effectively controlling the particle size of the finely crushed material. By setting up an intermediate screening stage and returning the oversize material to the crusher for reprocessing, excessive crushing can be avoided, resulting in too much fine powder, while ensuring that the final crushed particles have a particle size distribution within the required range.

[0029] This embodiment employs a two-stage crushing process combining coarse and fine crushing, with a screening and return mechanism after each stage to achieve particle size control during the crushing process. This staged crushing method allows for the selection of appropriate crushing equipment based on the initial size and hardness of the material. In the coarse crushing stage, the jaw crusher rapidly breaks down large pieces of material using compression and bending actions, while in the fine crushing stage, the roller crusher further refines the material using shearing and crushing actions. By controlling the gap size of the crushing equipment and combining it with screening circulation, crushed particles with a more concentrated and uniform particle size distribution can be obtained, providing suitable raw materials for subsequent aging treatment.

[0030] In one embodiment, the crushed particles are placed in a high-pressure reactor for aging treatment. A mixture of water vapor and carbon dioxide is introduced into the high-pressure reactor, controlling the volume ratio of water vapor to carbon dioxide to be 3:1, or alternatively 2:1 or 5:1. The total pressure inside the high-pressure reactor is adjusted to 0.5 MPa, or alternatively 0.3 MPa or 0.8 MPa, so that the partial pressure of water vapor reaches 0.2 MPa, or alternatively 0.1 MPa or 0.3 MPa. The temperature is increased from room temperature to 90°C, or alternatively 80°C or 100°C, at a rate of 2°C per minute, and then maintained at this temperature for aging for 1.5 hours, or alternatively 1 hour or 2 hours, allowing the water vapor and carbon dioxide to initially react with the material at a lower temperature. The temperature is then increased to 150°C, or alternatively 120°C or 180°C, at a rate of 1°C per minute, or alternatively 0.5°C per minute or 1.5°C per minute, and then maintained at this temperature for aging for 4 hours, or alternatively 3 hours or 6 hours, to obtain an intermediate aged product. The introduction of carbon dioxide creates a weakly acidic environment under the action of water vapor, which helps to modulate the interlayer structure of the hydrotalcite and promotes the regularization of the pores. The intermediate aging product is cooled to 50°C in a nitrogen atmosphere (40°C or 60°C can also be selected), depressurized, and then placed in an oven to dry at 70°C for 3 hours (60°C or 80°C for 2 to 4 hours) to remove any residual moisture that may have been adsorbed during the aging process, thus obtaining the aged product. This aging process is carried out in a high-pressure reactor, with crushed particles and mixed gas as input and the aging product as output. The trigger condition is that the temperature and pressure reach the set values, and then the process enters a constant-temperature stage.

[0031] In this embodiment, carbon dioxide is introduced into water vapor to create a mixed atmosphere of water vapor and carbon dioxide. By adjusting the ratio of the two and the total pressure, precise control of the atmosphere composition within the reactor is achieved. During the heating and aging process, carbon dioxide dissolves in the liquid film formed by water vapor on the particle surface, generating a weakly acidic environment. This environment helps promote the exchange of anions between the layers of hydrotalcite and the reconstruction of the lamellar structure, thereby forming a more regular pore structure. Simultaneously, a two-stage heating and aging process is employed: first, the gas fully wets the interior of the particles at a lower temperature, and then the temperature is raised to a higher temperature for structural reorganization, ensuring a more uniform and thorough aging process. Subsequent nitrogen cooling and low-temperature drying steps prevent the aging products from adsorbing moisture from the environment during the cooling process, which could affect their structural stability.

[0032] In one embodiment, the aging product is placed in a tube furnace for segmented calcination. The temperature is increased at a rate of 3°C per minute, or alternatively 2°C or 5°C per minute, to 220°C, or alternatively 200°C or 250°C, and then calcined at a constant temperature in air for 1.5 hours, or alternatively 1 hour or 2 hours. This stage, conducted in air, primarily aims to fully oxidize and decompose organic components such as sodium alginate, while simultaneously causing the initial decomposition of some metal salts, releasing gaseous products and initially forming a porous structure. After stopping the air supply, a vacuum is evacuated to a vacuum level of 0.092 MPa, or alternatively 0.09 MPa or 0.095 MPa, to remove any remaining air from the furnace. Then, nitrogen is introduced to atmospheric pressure to replace the furnace atmosphere. The temperature is then increased to 480℃, 400℃, or 550℃ at a rate of 2℃ per minute (or 1℃ or 3℃ per minute), and calcined at a constant temperature under a nitrogen atmosphere for 3 hours, 2 hours, or 4 hours. This further crystallizes the metal oxide, forming a stable composite metal oxide active phase, yielding the calcined product. The calcination process is performed in a tubular furnace, with the aging product and a preset temperature program as inputs, and the calcined product as the output. High-temperature calcination under a nitrogen atmosphere prevents excessive oxidation or undesirable phase transitions of the active metal components at high temperatures, while also avoiding sintering caused by localized overheating in an air atmosphere.

[0033] This embodiment employs a two-stage roasting process combining air and nitrogen atmospheres. First, the organic matter is oxidized and decomposed at a lower temperature under air atmosphere. While the heat release is concentrated at this stage, the heat can be released evenly by controlling the heating rate and holding time. Then, nitrogen is evacuated to replace the nitrogen, switching the furnace atmosphere to an inert atmosphere before the temperature is raised to a higher level for crystallization. This segmented process effectively avoids the risk of temperature runaway caused by the superposition of the exothermic oxidation of organic components and the crystallization process of the active phase. It is beneficial for obtaining a fine-grained, uniformly dispersed active phase, thereby improving the activity and thermal stability of the desulfurizer.

[0034] In one embodiment, the material obtained by any of the aforementioned preparation methods can be used as a desulfurizing agent for aviation kerosene. This desulfurizing agent is in the form of 20-60 mesh particles with a relatively uniform particle size distribution. Its internal structure consists of composite metal oxides, with the active components copper, zinc, and nickel existing in a highly dispersed state within the carrier, forming active centers for the synergistic effect of multiple metals. When used for aviation kerosene desulfurization, this desulfurizing agent can be packed into a fixed-bed adsorption tower. Under certain temperature and pressure conditions, kerosene flows through the desulfurizing agent bed, where sulfide molecules undergo chemical adsorption or coordination with the active sites on the surface of the desulfurizing agent, thereby achieving sulfide removal. After use, the desulfurizing agent can be regenerated through appropriate methods to restore its desulfurization activity.

[0035] The following is a description of a specific embodiment.

[0036] Experimental group: Prepare aviation kerosene desulfurizer according to the following steps.

[0037] S1: Copper nitrate, zinc nitrate and nickel nitrate are dissolved in deionized water to prepare a mixed metal salt solution, wherein the molar ratio of copper ions, zinc ions and nickel ions is 1:1.5:0.5, and the total molar concentration of metal ions in the mixed metal salt solution is 1.2 mol / L.

[0038] S2: Sodium alginate is added to the mixed metal salt solution and mixed at 65°C for 20 minutes under stirring to obtain the first mixture. Hydrotalcite powder is added to the first mixture and mixed at 65°C for 45 minutes under stirring to obtain the second mixture. Polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer is added to the second mixture and mixed at 70°C for 90 minutes under shear stirring to obtain a mixed slurry. The mass ratio of sodium alginate to hydrotalcite powder is 0.1:1, and the mass ratio of the polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer to sodium alginate is 1:1. The mass ratio of the mixed metal salt solution to the total mass of sodium alginate, hydrotalcite powder, and triblock copolymer is 15:1.

[0039] The polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer was prepared through the following steps: Polyethylene glycol and polypropylene glycol were mixed at a molar ratio of 1:3, heated to 90°C under a nitrogen atmosphere, and toluenesulfonic acid was added. The amount of catalyst added was 2% of the total mass of polyethylene glycol and polypropylene glycol. The mixture was stirred for 3 hours to obtain a first intermediate. The first intermediate was cooled to 45°C, and ethylene oxide was added. The molar ratio of ethylene oxide to the polypropylene glycol units in the first intermediate was 3:1. The mixture was reacted for 4 hours under a pressure of 0.3 MPa to obtain a second intermediate. The second intermediate was cooled to room temperature, washed with deionized water, and allowed to stand for separation. The organic phase was then collected and vacuum dried at 70°C for 6 hours to obtain the polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer.

[0040] S3: Place the mixed slurry in a vacuum drying oven, and under a vacuum of 0.08 MPa, heat it from room temperature to 55°C at a heating rate of 2°C / min, and dry it at a constant temperature for 3 hours. Then heat it to 90°C at a heating rate of 1°C / min and dry it at a constant temperature for 8 hours to obtain the dried product.

[0041] S4: Place the dried product in a jaw crusher for coarse crushing, so that the particle size of the coarsely crushed material is less than 5 mm. Pass the coarsely crushed material through a 10-mesh sieve, collect the oversize material and return it to the jaw crusher for coarse crushing again. Collect the undersize material and place it in a roller crusher for fine crushing, so that the particle size of the finely crushed material is less than 1 mm. Pass the finely crushed material through a 20-mesh sieve, collect the oversize material and return it to the roller crusher for fine crushing again. Collect the undersize material as crushed particles.

[0042] S5: Place the crushed particles in a high-pressure reactor. Introduce a mixture of water vapor and carbon dioxide into the reactor, maintaining a water vapor to carbon dioxide volume ratio of 3:1. Adjust the total pressure inside the reactor to 0.5 MPa, ensuring the water vapor partial pressure reaches 0.2 MPa. Increase the temperature from room temperature to 90°C at a rate of 2°C / min, and maintain this temperature for 1.5 hours. Then increase the temperature to 150°C at a rate of 1°C / min and maintain this temperature for 4 hours to obtain an intermediate aged product. Cool the intermediate aged product to 50°C in a nitrogen atmosphere, depressurize, and remove it. Place it in an oven and dry at 70°C for 3 hours to obtain the aged product.

[0043] S6: Place the aging product in a tube furnace and heat it to 220°C at a heating rate of 3°C / min. Calcinate it at a constant temperature in air for 1.5 hours. Stop the air supply, evacuate to a vacuum degree of 0.092 MPa, then introduce nitrogen to atmospheric pressure. Then heat it to 480°C at a heating rate of 2°C / min and calcine it at a constant temperature in nitrogen for 3 hours to obtain the calcined product.

[0044] S7: Sieve the roasted product and collect particles with a particle size range of 20 to 60 mesh to obtain aviation kerosene desulfurizer.

[0045] Control group 1: The difference between control group 1 and experimental group is that the hydrotalcite powder was replaced with an equal mass of γ-alumina powder, while the rest of the steps were the same as those of the experimental group.

[0046] Control group 2: The difference between control group 2 and experimental group is that sodium alginate is omitted, while the rest of the steps are the same as those of experimental group.

[0047] Control group 3: The difference between control group 3 and experimental group is that the polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer is omitted, while the other steps are the same as those of experimental group.

[0048] Control group 4: The difference between control group 4 and experimental group is that the hydrotalcite powder was replaced with an equal mass of γ-alumina powder and sodium alginate was omitted. The rest of the steps were the same as those of the experimental group.

[0049] Control group 5: The difference between control group 5 and experimental group is that the hydrotalcite powder was replaced with an equal mass of γ-alumina powder, and the polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer was omitted. The remaining steps were the same as those of the experimental group.

[0050] Control group 6: The difference between control group 6 and experimental group is that sodium alginate and polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer are omitted, while the rest of the steps are the same as those of experimental group.

[0051] Control group 7: The difference between control group 7 and experimental group is that the hydrotalcite powder was replaced with an equal mass of γ-alumina powder, and sodium alginate and polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer were omitted. The remaining steps were the same as those of the experimental group.

[0052] Control group 8: The difference between the control group 8 and the experimental group is that the aging method in S5 is replaced with a conventional aging method, that is, the crushed particles are placed in a muffle furnace and aged at a constant temperature of 150°C for 5.5 hours in an air atmosphere. The remaining steps are the same as those in the experimental group.

[0053] Desulfurization performance test: 20 mL of the desulfurizing agent sample prepared in each embodiment was loaded into a fixed-bed reactor with an inner diameter of 10 mm. The aviation kerosene used in the test was jet fuel supplied by a refinery, with an initial sulfur content of 850 μg / g, and the main sulfide types included thiols, thioethers, and thiophene compounds. The test conditions were: reaction temperature 60℃, reaction pressure 0.5 MPa, and liquid hourly space velocity 2.0 h⁻¹. The sulfur content in the aviation kerosene after the reaction was determined by microcoulometric method, and the desulfurization rate was calculated according to the following formula: Desulfurization rate = (Initial sulfur content - Post-treatment sulfur content) / Initial sulfur content × 100% The desulfurization rate of the desulfurizing agent was measured after 2 hours, 48 ​​hours and 96 hours of operation to evaluate its initial desulfurization activity and stability.

[0054] Sulfur capacity test: Under the same test conditions, the process continues until the sulfur content at the desulfurizing agent bed outlet reaches 10% of the initial sulfur content, at which point the desulfurizing agent is considered to have penetrated. The total mass of sulfur removed per unit mass of desulfurizing agent is calculated, which is the dynamic sulfur capacity, expressed in mg / g.

[0055] Regeneration performance test: The desulfurizing agent after penetration was removed and placed in a tubular furnace for regeneration at 450°C for 2 hours in air atmosphere. The regenerated desulfurizing agent was then tested again under the same test conditions. The desulfurization rate was recorded after 48 hours of the second operation, and the regeneration test was repeated 3 times to evaluate the regeneration stability of the desulfurizing agent.

[0056] Table 1 Comparison of Performance Parameters As shown in Table 1, the experimental group outperformed the control groups in all evaluation indicators. Regarding initial desulfurization activity, the experimental group achieved an initial desulfurization rate of 99.2%, while control groups 1, 2, and 3 achieved 96.5%, 97.2%, and 97.8%, respectively. Control groups 4 to 7 further decreased to between 91.8% and 95.1%, and control group 8 achieved 96.9%. This indicates that the simultaneous presence of hydrotalcite, sodium alginate, and the triblock copolymer creates a synergistic effect, resulting in more uniform dispersion of the active components in the desulfurizing agent and more exposed active sites, thus exhibiting higher desulfurization efficiency in the initial stage. When any one of these components was replaced with a conventional carrier or omitted, the initial desulfurization rate decreased to varying degrees.

[0057] Regarding operational stability, the desulfurization rates of the experimental group remained at 98.5% and 96.8% after 48 and 96 hours of operation, respectively, with a relatively small decrease. In contrast, the desulfurization rates of control groups 1 decreased to 89.2% after 96 hours, control group 2 to 90.6%, control group 3 to 91.8%, control groups 4 to 7 further decreased to between 79.2% and 86.3%, and control group 8 to 90.1%. The experimental group maintained a high desulfurization rate even after long-term operation, indicating that the combined effect of hydrotalcite as a carrier precursor, sodium alginate as a dispersant and binder, and triblock copolymer as a structure directing agent resulted in a more robust immobilization of the active components on the carrier, a more stable pore structure, and the ability to continuously provide effective mass transfer channels for sulfide molecules.

[0058] Regarding dynamic sulfur capacity, the experimental group reached 18.6 mg / g, while control groups 1, 2, and 3 were 15.3 mg / g, 16.1 mg / g, and 16.9 mg / g, respectively. Control groups 4 to 7 decreased to between 11.2 mg / g and 13.8 mg / g, and control group 8 was 15.9 mg / g. The experimental group had a significantly higher sulfur capacity, indicating that the combination of hydrotalcite, sodium alginate, and triblock copolymer used in this invention can effectively improve the utilization rate of the active components, and that a unit mass of desulfurizing agent can adsorb more sulfides.

[0059] In terms of regeneration performance, after three regenerations, the desulfurization rate of the experimental group remained at 95.2% after 48 hours, while that of control groups 1, 2, and 3 decreased to 88.7%, 90.5%, and 91.2%, respectively. Control groups 4 to 7 further decreased to between 78.9% and 85.1%, and control group 8 decreased to 89.3%. The experimental group exhibited excellent regeneration stability, indicating that the structure synergistically constructed by hydrotalcite, sodium alginate, and triblock copolymer can be well maintained during repeated regeneration, and the active components are not easily deactivated by sintering due to repeated calcination.

[0060] Comparing control groups 1, 2, and 3 with the experimental group, it can be seen that when hydrotalcite is replaced with conventional γ-alumina, the dispersibility and pore regularity of the active components decrease due to the lack of the layered structure and interlayer anion exchange capacity unique to hydrotalcite, resulting in reduced desulfurization performance. When sodium alginate is omitted, the stabilizing effect of the polymeric dispersant is lacking in the slurry system, making it easier for metal ions to migrate and aggregate during drying, leading to poorer uniformity of the active component distribution. When the triblock copolymer is omitted, the steric hindrance effect and structure guiding effect are lacking, adversely affecting the regularity of the pore structure and the dispersibility of the active components.

[0061] Comparing control groups 4, 5, and 6 with the experimental group, it can be seen that when two components are missing simultaneously, the decrease in desulfurization performance is greater than when only one component is missing, indicating a synergistic effect among the components. Control group 7, which replaced hydrotalcite with a conventional carrier and omitted sodium alginate and the triblock copolymer, showed significantly lower performance indicators than the experimental group, further confirming the necessity and synergistic effect of the combination of hydrotalcite, sodium alginate, and the triblock copolymer.

[0062] Comparing the control group 8 with the experimental group, it can be seen that the segmented aging process under a mixed atmosphere of water vapor and carbon dioxide adopted in this invention can more effectively regulate the pore structure of the desulfurizing agent precursor and the interaction between the active components and the carrier compared with conventional air atmosphere aging, thus showing better performance in terms of desulfurization activity, stability and regeneration performance.

[0063] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A method for preparing an aviation kerosene desulfurizing agent, characterized in that, include: S1: Dissolve soluble copper salt, soluble zinc salt, and soluble nickel salt in deionized water to prepare a mixed metal salt solution, wherein the molar ratio of copper ions, zinc ions, and nickel ions is 1:(1.2-1.8):(0.3-0.8), and the total molar concentration of metal ions in the mixed metal salt solution is 0.9-1.4 mol / L; S2: Add hydrotalcite powder, sodium alginate, and polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer to a mixed metal salt solution, wherein the mass ratio of sodium alginate to hydrotalcite powder is (0.05-0.2):1, and the mass ratio of polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer to sodium alginate is (0.5-1.5):

1. Mix under stirring conditions at 60-80℃ to obtain a mixed slurry. S3: Dry the mixed slurry at 80-100℃ to obtain the dried product; S4: Crush the dried product to obtain crushed particles; S5: Place the crushed particles in an atmosphere with a water vapor partial pressure of 0.1-0.3 MPa and age them at 120-180 ℃ to obtain the aged product; S6: The aged product is calcined at 400-550 ℃ to obtain the calcined product; S7: Sieve the roasted product and collect particles with a particle size range of 20-60 mesh to obtain aviation kerosene desulfurizer.

2. The method for preparing the aviation kerosene desulfurizer according to claim 1, characterized in that, In step S2, sodium alginate is added to the mixed metal salt solution and mixed at 60-70 °C for 15-30 minutes under stirring to obtain a first mixture; hydrotalcite powder is added to the first mixture and mixed at 60-70 °C for 30-60 minutes under stirring to obtain a second mixture; polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer is added to the second mixture and mixed at 60-80 °C for 60-120 minutes under shear stirring to obtain a mixed slurry. The mass ratio of the mixed metal salt solution to sodium alginate, hydrotalcite powder, and polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer is (10-20):

1.

3. The method for preparing the aviation kerosene desulfurizer according to claim 1, characterized in that, The polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer is prepared by the following steps: Polyethylene glycol and polypropylene glycol are mixed in a molar ratio of 1:(2-4), heated to 80-100 °C under a nitrogen atmosphere, and a catalyst is added. The catalyst is toluenesulfonic acid, and the amount of catalyst added is 0.5-5% of the total mass of polyethylene glycol and polypropylene glycol. The mixture is stirred for 2-4 hours to obtain the first intermediate. The first intermediate is cooled to 40-50 °C, and ethylene oxide is added. The molar ratio of ethylene oxide to the polypropylene glycol unit in the first intermediate is (2-4):

1. The reaction is carried out for 3-6 hours under a pressure of 0.2-0.4 MPa to obtain the second intermediate. The second intermediate was cooled to room temperature, washed with deionized water, allowed to stand and separate into layers, and the organic phase was taken. The organic phase was then vacuum dried at 60-80 °C for 4-8 hours to obtain a polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer.

4. The method for preparing the aviation kerosene desulfurizer as described in claim 1, characterized in that, The mixed slurry was placed in a vacuum drying oven and heated from room temperature to 50-60 ℃ at a heating rate of 1-3 ℃ / min under a vacuum of 0.06-0.09 MPa. It was then dried at this temperature for 2-4 hours, and then heated to 80-100 ℃ at a heating rate of 0.5-1.5 ℃ / min. It was then dried at this temperature for 6-10 hours to obtain the dried product.

5. The method for preparing the aviation kerosene desulfurizer as described in claim 1, characterized in that, In step S4, the dried product is coarsely crushed in a jaw crusher to make the particle size of the coarsely crushed material less than 5 mm. The coarsely crushed material is then passed through a 10-mesh sieve, and the material on the sieve is collected and returned to the jaw crusher for further coarse crushing. The material under the sieve is then placed in a roller crusher for further fine crushing to make the particle size of the finely crushed material less than 1 mm. The finely crushed material is then passed through a 20-mesh sieve, and the material on the sieve is collected and returned to the roller crusher for further fine crushing. The material under the sieve is collected as crushed particles.

6. The method for preparing the aviation kerosene desulfurizer as described in claim 1, characterized in that, In S5, the crushed particles are placed in a high-pressure reactor. A mixture of water vapor and carbon dioxide is introduced into the reactor, and the volume ratio of water vapor to carbon dioxide is controlled at (2-5):

1. The total pressure inside the reactor is adjusted to 0.3-0.8 MPa, so that the partial pressure of water vapor reaches 0.1-0.3 MPa. The temperature is increased from room temperature to 80-100℃ at a rate of 1-3℃ / min, and aged at a constant temperature for 1-2 hours. Then, the temperature is increased to 120-180℃ at a rate of 0.5-1.5℃ / min, and aged at a constant temperature for 3-6 hours to obtain an intermediate aged product. The intermediate aged product is cooled to 40-60℃ in a nitrogen atmosphere, depressurized, and then placed in an oven to dry at 60-80℃ for 2-4 hours to obtain the aged product.

7. The method for preparing the aviation kerosene desulfurizer as described in claim 1, characterized in that, In S6, the aging product is placed in a tube furnace and heated to 200-250 ℃ at a heating rate of 2-5 ℃ / min. It is then calcined at a constant temperature in air for 1-2 hours. After stopping the air supply, the vacuum is evacuated to a vacuum degree of 0.09-0.095 MPa. Nitrogen gas is then introduced to atmospheric pressure, and the temperature is further increased to 400-550 ℃ at a heating rate of 1-3 ℃ / min. The product is then calcined at a constant temperature in nitrogen for 2-4 hours to obtain the calcined product.

8. Aviation kerosene desulfurizer, characterized in that, Prepared by the method described in any one of claims 1-7.

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