Alumina support and its preparation method, hydrodesulfurization catalyst and its preparation method

Abstract

This invention relates to an alumina support and its preparation method, as well as a hydrodesulfurization catalyst and its preparation method. The alumina support comprises a cobalt-manganese solid solution. The preparation method includes mixing the cobalt-manganese solid solution and alumina powder to prepare a slurry and dispersing it; separating the liquid and solid phases of the slurry; drying the solid to obtain alumina powder containing the cobalt-manganese solid solution; dry-mixing the alumina powder containing the cobalt-manganese solid solution with an extrusion aid; then mixing it with a binder and water, followed by extrusion molding; drying and calcination. The aforementioned support is used in a hydrodesulfurization catalyst.

Description

Technical Field

[0001] This invention relates to a catalytic material and a hydrogenation catalyst containing the catalytic material, specifically to an alumina material and a hydrodesulfurization catalyst containing the alumina material. Background Technology

[0002] To control air pollution caused by vehicle exhaust emissions, my country has accelerated the pace of upgrading gasoline quality. The China VI (A) gasoline quality standard, requiring a sulfur content of less than 10 mg / kg and an olefin content of less than 18% (volume fraction), was implemented on January 1, 2019. The China VI (B) standard (sulfur content less than 10 mg / kg and olefin content less than 15%) will be implemented on January 1, 2023. In my country, high-sulfur, high-olefin-content catalytic cracking (FCC) gasoline accounts for more than 60% of the total gasoline pool, contributing over 90% of the sulfur and olefin content in commercial gasoline. Therefore, the clean production of FCC gasoline is crucial for the production of clean gasoline for vehicles in my country. Currently, among the FCC gasoline upgrade technologies already in operation in my country, over 60% of the units adopt the selective hydrodesulfurization (SPD) process. The SPD catalyst, as the core of this technology, has long been a focus of research for scholars both domestically and internationally.

[0003] As a crucial component of catalysts, supports not only enhance the dispersibility of active components but also provide "transport channels" for reactant and product molecules through their pores, thereby improving metal utilization. Based on these roles in catalysts, extensive and mature research has been conducted on supports over the years, primarily focusing on controlling the pore size of alumina materials or shaped supports, optimizing acidity, and modifying them by compounding or blending with other oxides or metal salt precursors.

[0004] US 4140626 discloses a class of catalysts supported on alumina and magnesium oxide, wherein the catalyst contains 3 wt% CoO, 16 wt% MoO3, 70 wt% MgO, and 11 wt% Al2O3, and is used in hydrodesulfurization reactions. At a desulfurization rate of 96%, the olefin saturation rate is 64%, and the desulfurization selectivity is significantly improved compared to conventional selective hydrodesulfurization catalysts. However, the mechanical strength of this catalyst is relatively poor, making it difficult to meet the requirements of industrial applications.

[0005] US 5348928 reports a hydrodesulfurization catalyst using weakly acidic or non-acidic activated alumina as a support, Co-Mo as the main active component, and with the addition of small amounts of magnesium and alkali metals. It exhibits good selectivity and stability in hydrodesulfurization applications, but its specific surface area is relatively small (<150 m²). 2 / g), which can easily lead to uneven dispersion of active components, thereby affecting the selectivity of hydrodesulfurization of the catalyst.

[0006] CN 200710177577.X discloses a selective hydrodesulfurization catalyst modified with multiple additives and its preparation method. The catalyst uses a composite oxide of alumina and boron oxide as the support, and Mg, K, and P are used as additives to modulate the support, supporting the active components cobalt and molybdenum. The prepared catalyst is applied to FCC gasoline hydrodesulfurization. At a desulfurization rate of 86%, the olefin saturation is 6-7 v, and the octane number loss is 0.9 units.

[0007] While the aforementioned patents improved the performance of hydrodesulfurization catalysts through carrier optimization, they also suffered from problems such as high active component dosage, relatively poor dispersibility, and low utilization efficiency. Therefore, researchers have also conducted some related research on alumina materials containing spinel structures.

[0008] CN 201210178395.5 discloses a method for preparing nano-zinc-aluminum spinel. The method involves dissolving zinc salt in water, adding an aluminum source, stirring for 10-30 minutes, adding a pore-expanding agent, stirring, aging at 20-100℃ for 30-60 minutes, drying, and calcining at 500-1200℃. The raw material molar ratio is Zn:Al:water = 1:2:16-35. Based on the mass of zinc oxide as 100%, the amount of pore-expanding agent added is 0.5-30%. The pore-expanding agent is one or more of sucrose, glycerol, ammonium carbonate, ammonium bicarbonate, polystyrene emulsion, and polyethylene glycol. The specific surface area of ​​the synthesized zinc-aluminum spinel ranges from 60 to 300 m². 2 / g. This method uses a low zinc-aluminum ratio in the feed and adds a pore-expanding agent during the preparation process, resulting only in zinc-aluminum spinel, without uniformly dispersed zinc oxide.

[0009] CN 201610532074.9 discloses a selective hydrodesulfurization catalyst and its preparation method. The hydrodesulfurization catalyst, by mass of oxides, contains: active component CoO 3-5%, MoO3 10-13%, and the auxiliary agents for modifying the support have boron, phosphorus, and potassium contents of B2O3 2-3%, P2O5 1-2%, and K2O 1-1.5%, respectively. The composite oxide support comprises 75.5-83%, and the catalyst support is a zinc oxide and alumina composite oxide containing zinc-aluminum spinel prepared by alternating titration with non-constant pH. Although this catalyst exhibits good desulfurization selectivity and stability, the preparation process is difficult to industrialize.

[0010] CN 201911012690.1 discloses a hydrogenation deoxygenation sulfur-free nickel-based Ni / Al2O3-ZrO2 catalyst, wherein the catalyst is composed of an active component Ni and an Al2O3-ZrO2 support, with a Ni to Al2O3-ZrO2 support mass ratio of 0.08 to 0.12:1; in the hydrogenation deoxygenation sulfur-free nickel-based Ni / Al2O3-ZrO2 catalyst, the Al to Zr molar ratio is 0.8 to 2:1, and Zr... O2 interacts with Al2O3, forming Zr-O-Al bonds that penetrate into each other's lattices to form a solid solution. This prevents Ni from entering the Al2O3 lattice and forming nickel-aluminum spinel, thus weakening the interaction between the active component Ni and Al2O3 in the Al2O3-ZrO2 support. This results in Ni being more uniformly dispersed on the surface of the Al2O3-ZrO2 support, improving the Lewis acid sites on the Al2O3-ZrO2 support surface and the thermal stability of the Al2O3-ZrO2 support, and lowering the reduction temperature of the catalyst.

[0011] In summary, while modifying alumina materials or molded supports can improve the economy and reactivity of alumina as a catalyst, it also presents certain shortcomings. For example, the modifying agents introduced into alumina materials currently have high dosage requirements and relatively poor dispersibility after introduction. Furthermore, they tend to interact strongly with alumina during high-temperature processing, forming aluminate compounds that affect the catalyst's activity and stability. Currently, among the publicly disclosed alumina materials containing spinel structures, magnesium aluminum spinel and zinc aluminum spinel are the most common, primarily composed of spinels formed from divalent metals and aluminum. Although the idea of ​​introducing divalent metals to occupy Al2O3 lattices to form spinels aims to improve the dispersibility of the active components, the low proportion of spinel-structured phases and their complex physical properties result in a less significant catalytic effect. Therefore, it is both urgent and necessary to continuously and thoroughly select additives and introduce them into catalysts through specific processes, thereby reducing their dosage and improving their utilization efficiency, so as to better exert the performance of catalysts. Summary of the Invention

[0012] The purpose of this invention is to provide an alumina support and its preparation method, as well as a hydrodesulfurization catalyst containing the alumina support and its preparation method, in order to solve the problem in the prior art where the distribution of active metal components on the catalyst is uneven and the metal utilization rate is low, resulting in an unbalanced release of catalyst activity during the start-up and operation of the device.

[0013] To achieve the above objectives, the present invention provides an alumina support comprising, by weight 100%, 0.1-10% of a cobalt-manganese solid solution (Co). x Mn y O4)n, where 0.5≤n≤10, 0<x<5, 0<y<5. The carrier preferably includes 0.5~5% cobalt-manganese solid solution; the cobalt-manganese solid solution preferably has 0.5<x<2, 0.5<y<3, 1≤n≤5.

[0014] The solid solution described herein possesses crystalline phase characteristics. These crystalline phase characteristics refer to the characteristic peaks belonging to the cobalt-manganese solid solution that can be detected by X-ray diffraction. The cobalt-manganese solid solution only needs to meet the requirements of the chemical molar composition of the substance and possess crystalline phase characteristics. The content of the solid solution in the alumina support should be controlled within the range of 0.1% to 10%. It should not be too low, otherwise it will not achieve the desired effect; nor should it be too high, as this will affect the overall pore distribution of the support and increase the amount of metal used in the hydrodesulfurization catalyst, weakening metal dispersion. Consequently, without a significant improvement in catalyst performance, this increases the processing and production costs, which is not economically reasonable.

[0015] The alumina support of the present invention, wherein the cobalt-manganese solid solution comprises one or more of CoMn2O4, Co2MnO4, CoMnO3 and Co2Mn3O8.

[0016] The alumina support of the present invention comprises a cubic Co₂MnO₄ solid solution. The cubic Co₂MnO₄ exhibits characteristic diffraction peaks at 2θ = 18.6°, 30.7°, 36.2°, 44.1°, 54.6°, 58.4°, 64.2°, and 92.1°.

[0017] In the alumina carrier of the present invention, the proportion of the Co2MnO4 crystalline phase in the cobalt-manganese solid solution phase composition is greater than or equal to 50%.

[0018] The crystal phase composition of the cobalt-manganese solid solution is mainly determined by the material synthesis process, including factors such as composition ratio and heat treatment conditions. The preparation method of the cobalt-manganese solid solution can adopt methods mentioned in existing literature, such as the one described in "The Formation Process and FT Reaction Performance of Nano-Spinel Co2MnO4" in the 1998 issue of the *Journal of Catalysis* (Vol. 19, No. 1), which also discloses its preparation method: a solution is prepared using cobalt nitrate and manganese nitrate as raw materials, and citric acid is added in a certain proportion and mixed evenly. This solution is placed in a 60°C water bath to slowly evaporate the water, gradually forming a sol, which then transforms into a gel. This gel is dried in air at 110°C for 4 hours, and then heat-treated at different temperatures to obtain cobalt-manganese solid solutions with different particle sizes. Chinese invention patent CN 96117198.7 also discloses nano-sized cobalt-manganese spinel, its preparation method, and its uses. The preparation method includes: adding citric acid or a mixture of citric acid and acetylacetone as an organic ligand to an aqueous solution of cobalt nitrate and manganese nitrate; adjusting the pH to 0 to 1.5; forming a gel at 50 to 70°C; drying; and calcining to obtain nano-sized cobalt-manganese spinel. These prior art techniques disclose the preparation of cobalt-manganese solid solutions, which can be incorporated herein by reference.

[0019] The cobalt-manganese solid solution of the present invention can also be prepared by the following method: adding ammonia water dropwise to a mixed solution of cobalt nitrate and manganese nitrate while stirring, adjusting the pH value of the solution to 8-11 to obtain a precipitate; filtering, washing with water, drying, and calcining at 500-1100℃ for 2-6 hours to obtain the cobalt-manganese solid solution.

[0020] In the preparation of the cobalt-manganese solid solution in the alumina carrier of the present invention, the drying can be carried out at room temperature or at a certain temperature, preferably at 80-150°C for 2-10 hours.

[0021] To achieve the above objectives, the present invention also provides a method for preparing the alumina support, comprising the following steps:

[0022] (1) Pretreatment of powder: Take cobalt-manganese solid solution with a particle size of less than 10 μm and alumina powder, add water and stir to prepare slurry, disperse the slurry to control the particle size of the slurry to less than 5 μm; separate the liquid and solid of the slurry, and dry the solid to obtain alumina powder containing cobalt-manganese solid solution.

[0023] (2) Carrier molding: Alumina powder containing cobalt-manganese solid solution and extrusion aid are dry-mixed, then mixed with adhesive and water, kneaded for 20-60 minutes and then extruded into strips;

[0024] (3) Heat treatment of the carrier: The extruded carrier is dried and calcined at a temperature of 500-650℃ for 4-8 hours to obtain a strip-shaped alumina carrier containing cobalt-manganese solid solution.

[0025] The alumina carrier preparation method of the present invention includes drying at room temperature or at a certain temperature, preferably at 80-150°C for 2-10 hours.

[0026] The alumina carrier preparation method of the present invention uses conventional techniques in the field for dispersing the slurry in step (1), such as ball milling dispersion and ultrasonic dispersion, as long as the effect can meet the particle size requirements of the present invention.

[0027] The method for preparing the alumina carrier according to the present invention includes a colloidal solvent being an acid, and the amount of colloidal solvent used being 1-10% of the mass of the cobalt-manganese solid solution alumina powder, preferably 1-5%. The colloidal solvent can be an organic acid or an inorganic acid.

[0028] The method for preparing the alumina carrier according to the present invention, wherein the colloidal solvent is one or more of oxalic acid, citric acid, nitric acid and hydrochloric acid.

[0029] The method for preparing the alumina carrier according to the present invention includes the use of guar gum powder as the extrusion aid, which is 2-10% of the mass of the cobalt-manganese solid solution alumina powder, preferably 3-7%. Other conventional extrusion aids are also applicable.

[0030] To achieve the above objectives, the present invention also provides a hydrodesulfurization catalyst, comprising, based on 100 parts of catalyst components: 70-98 parts of the above-mentioned alumina support, 0.5-20 parts of Group VIB metal oxides and 0.1-10 parts of Group VIII metal oxides, wherein the Group VIII metal oxides include oxides of Co; cobalt is calculated as oxide, and the mass of Co in the alumina support is lower than that of Co supported on the catalyst.

[0031] The hydrodesulfurization catalyst of the present invention comprises a group VIB metal oxide including tungsten oxide and / or molybdenum oxide, and the group VIII metal oxide further includes nickel oxide.

[0032] The hydrodesulfurization catalyst of the present invention comprises, based on 100 parts of catalyst components, 80-95 parts of the above-mentioned alumina support, 4-15 parts of group VIB metal oxide and 0.5-6 parts of group VIII metal oxide.

[0033] The metal components introduced during the preparation of the hydrodesulfurization catalyst of this invention can exist in any decomposable form, such as oxides, halides, or salts. They can be prepared using techniques known in the art. For example, the article "Development and Performance Evaluation of Catalysts for Deep Hydrodesulfurization of Catalysts for Catalytic Cracking of Gasoline" in Volume 36, Issue 7 of *Chemical Industry Progress* in 2017 describes: "The active components are sequentially dissolved in ammonia water to prepare a stable mixed solution of active metals. This solution is then impregnated onto a support in equal volumes for 4 hours, dried at 120°C for 4 hours, and calcined at 500°C for 4 hours to obtain the catalytic gasoline hydrodesulfurization catalyst."

[0034] The hydrodesulfurization catalyst described in this invention can also be prepared using the spray impregnation method provided by this invention, specifically including the following steps:

[0035] (1) Weigh out the group VIB metal precursor salt and the group VIII metal precursor salt, and test the saturated water absorption rate of the alumina support to determine the amount of dissolved water of the metal precursor salt.

[0036] (2) Add group VIB metal precursor salt and group VIII metal precursor salt to deionized water, and adjust the pH value by introducing ammonia water so that the group VIB metal precursor salt and group VIII metal precursor salt are completely dissolved into a stable mixed solution.

[0037] (3) The mixed solution is sprayed onto the alumina support in the form of a mist by spraying to obtain the catalyst precursor;

[0038] (4) The catalyst precursor is dried and calcined at 550-650°C for 4-8 hours. The drying can be carried out at room temperature or at a certain temperature. Preferably, it is dried at 120-150°C for 4-8 hours.

[0039] The beneficial effects of this invention are:

[0040] This invention provides a hydrodesulfurization catalyst comprising a cobalt-manganese solid solution. Cobalt is introduced into the catalyst in different forms at different stages of the hydrogenation catalyst preparation process, enabling the regulation of cobalt grain distribution. This effectively controls the rapid aggregation and growth of cobalt grains when the catalyst is directly loaded with cobalt, thus affecting its modification effect on the main active component. Introducing some cobalt into the support in the form of a cobalt-manganese solid solution weakens the interaction between cobalt and the support, thereby better synergizing with the main active component to exert hydrodesulfurization activity and selectivity. Furthermore, the cobalt content in the alumina support is lower than that in the catalyst loaded with Group VIII metals, thus forming a metal concentration gradient. This improves the dispersion of the active component on the support, thereby solving the problem of low metal utilization in hydrodesulfurization catalysts. It also improves the imbalance of activity release during the reaction process, such as excessively high initial activity at the beginning of the process and excessively rapid temperature rise at the end. Attached Figure Description

[0041] Figure 1 The image shows the XRD pattern of the alumina support sample containing a cobalt-manganese solid solution prepared in Example 2. Detailed Implementation

[0042] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0043] To further illustrate the effects of the method and catalyst used in this invention, examples are given using the hydrodesulfurization catalyst containing cobalt-manganese solid solution prepared in this invention and the corresponding FCC gasoline hydrodesulfurization reaction. However, this invention is not limited to the following examples.

[0044] Sources of raw materials used in the preparation of the support and catalyst:

[0045] All raw materials and reagents used in this invention are commercially available products.

[0046] Sources of raw materials used in hydrodesulfurization reactions:

[0047] This invention uses heavy gasoline obtained by cutting FCC full-fraction gasoline from Hohhot Petrochemical through a cutting tower as raw material. The sulfur content is 119.3 mg / kg, the olefin content is 27.13 v%, and the RON content is 85.6%.

[0048] The selected hydrodesulfurization reaction process conditions are as follows:

[0049] The hydrodesulfurization catalyst was loaded into a 50 mL fixed-bed adiabatic reactor for reaction performance evaluation. Prior to evaluation, the hydrodesulfurization catalyst underwent pre-sulfurization treatment using sulfurized oil. The treatment was conducted under a hydrogen-containing atmosphere, using straight-run gasoline as the sulfurized oil and CS2 as the sulfurizing agent, at a pressure of 3.0 MPa and a volumetric hourly space velocity of 3.0 h⁻¹. 1 Sulfurization was performed at a hydrogen-to-oil volume ratio of 350:1. During sulfurization, the catalyst bed temperature was increased at a rate of 20℃ / h and held at two temperature ranges of 230℃ and 280℃ for 5 hours. After the pre-sulfurization process was completed, the reaction operation conditions were adjusted to start-up conditions, and the sulfiding oil was switched to heavy gasoline cut from Hohhot Petrochemical Plant, initiating the reaction. The reaction operation conditions were: inlet temperature 230℃, pressure 1.6MPa, and volume hourly space velocity 3.0 h⁻¹. 1 The hydrogen-to-oil volume ratio is 320:1.

[0050] The product desulfurization rate, olefin saturation rate, and research octane number (RON) loss are calculated using the following formulas:

[0051]

[0052]

[0053] Research Octane Number (RON) Loss = Research Octane Number of Reactants - Research Octane Number of Reactants

[0054] The analytical methods for reactants and products during the reaction are as follows:

[0055] The sulfur content of the oil products described in this invention was analyzed using a TSN-2000 sulfur-nitrogen analyzer. The oil composition was analyzed using an Agilent 7890B gas chromatograph, and data processing was performed using an HW-2000PONA analytical chromatography workstation. The research octane number (RON) of the oil products was tested using an octane rating analyzer.

[0056] Example 1

[0057] Co 1.8 Mn 1.2 Preparation of O4: 266.4 g of cobalt nitrate and 172.2 g of manganese nitrate were dissolved in deionized water to prepare a cobalt-manganese nitrate mixed solution. 2 mol / L ammonia solution was added dropwise to this mixed solution while stirring, adjusting the pH to 9.8. This process yielded a precipitate, which was filtered, washed with water, dried at 130℃ for 5 hours, and calcined at 950℃ for 6 hours to obtain O4 with the molecular formula Co. 1.8 Mn 1.2 Cobalt-manganese solid solution of O4.

[0058] Take 5.4g of Co with a particle size of 10μm. 1.8 Mn 1.2 O4 and 385.2 g of pseudoboehmite powder were sequentially added to deionized water, with high-speed stirring required during the addition process to obtain a mixed slurry. The slurry was then ball-milled to disperse it, yielding a highly dispersed slurry with a particle size of 4 μm. The highly dispersed slurry was centrifuged to obtain a solid material, which was then dried at 100℃ for 6 hours to obtain a Co-containing solid. 1.8 Mn 1.2 O4 pseudoboehmite powder.

[0059] Weigh 250.0g of pseudoboehmite powder containing solid solution and add 4.9g of guar gum powder to a kneader and mix evenly. Then, add an aqueous solution containing 2.8g of nitric acid to the powder and knead for 35 minutes to obtain a clump of material, which is then extruded into strips to finally obtain a Co-containing material. 1.8 Mn 1.2 O4-containing strip-shaped alumina support. The alumina was dried at 90℃ for 8 hours and calcined at 600℃ for 4 hours to obtain a Co-containing... 1.8 Mn1.2 Alumina carrier A-1 of O4.

[0060] 90.0 g of A-1 alumina support was weighed and a catalyst was prepared by equal-volume impregnation. The water absorption rate of the alumina support was tested, and based on the water absorption rate, 75 g of ammonia solution was weighed and prepared (the mass ratio of ammonia to water was 5.5:4.5). Then, 11.3 g of ammonium heptamolybdate and 39.1 g of cobalt acetate were weighed and added to the ammonia solution. The mixture was stirred and dissolved to obtain a stable impregnation solution. The impregnated support yielded the catalyst precursor, which was dried at 120 °C for 7 h and calcined at 580 °C for 5 h to obtain catalyst A-1.

[0061] Example 2

[0062] Preparation of Co2MnO4: The difference from Example 1 is that 153.8g of cobalt nitrate and 77.5g of manganese nitrate were added, and ammonia water was added dropwise to adjust the pH of the solution to 10.5. After the precipitate was formed, it was filtered, washed with water, dried at 100℃ for 4h, and calcined at 830℃ for 3h to obtain a cobalt-manganese solid solution with the molecular formula Co2MnO4.

[0063] A mixed slurry was prepared by taking 9.4 g of Co2MnO4 with a particle size of 10 μm and 466.8 g of boehmite powder. This slurry was then dispersed by ball milling to obtain a highly dispersed slurry with a particle size of 3 μm. The highly dispersed slurry was centrifuged to obtain a solid material, which was then dried at 120℃ for 4 h to obtain boehmite powder containing Co2MnO4.

[0064] 230.0 g of pseudoboehmite powder containing solid solution was weighed and dry-mixed with 8.1 g of guar gum powder. An aqueous solution containing 3.5 g of nitric acid and 3.5 g of citric acid was then added to the powder mixture and kneaded for 60 minutes to obtain a clump. This clump was then extruded into strips to obtain a Co₂MnO₄-containing alumina support. After drying at 120℃ for 4 hours and calcining at 530℃ for 6 hours, Co₂MnO₄-containing alumina support A-2 was obtained, and its XRD pattern is shown below. Figure 1 As shown in the figure. The XRD pattern of the sample reveals characteristic peaks of cobalt-manganese solid solution and γ-Al₂O₃, with the Co₂MnO₄ phase accounting for ≥78% of the cobalt-manganese solid solution phase composition. This indicates that the material is an alumina material containing cobalt-manganese solid solution.

[0065] 100.0 g of A-2 alumina support was weighed and a catalyst was prepared by equal-volume impregnation. The water absorption rate of the alumina support was tested, and based on the water absorption rate, 80 g of ammonia solution (mass ratio of ammonia to water was 3:7) was prepared. Then, 18.9 g of ammonium heptamolybdate and 15.3 g of cobalt nitrate were weighed and added to the ammonia solution, and dissolved while stirring to obtain a stable impregnation solution. The impregnated support yielded the catalyst precursor, which was dried at 150 °C for 4 h and calcined at 650 °C for 4 h to obtain catalyst A-2.

[0066] Example 3

[0067] Preparation of Co2Mn3O8: The difference from Example 1 is that 205.3g of cobalt nitrate and 289.9g of manganese nitrate were added, and ammonia water was added dropwise to adjust the pH of the solution to 8.6. After the precipitate was formed, it was filtered, washed with water, dried at 150℃ for 6h, and calcined at 1060℃ for 2h to obtain a cobalt-manganese solid solution with the molecular formula Co2Mn3O8.

[0068] A mixed slurry was prepared by taking 2.1 g of Co2Mn3O8 with a particle size of 10 μm and 581.9 g of boehmite powder. This slurry was then ultrasonically dispersed to obtain a highly dispersed slurry with a particle size of 5 μm. The highly dispersed slurry was centrifuged to obtain solid material, which was then dried at 80℃ for 9 h to obtain boehmite powder containing Co2Mn3O8.

[0069] 160.0 g of pseudoboehmite powder containing solid solution and 8.1 g of guar gum powder were weighed and added to a kneader and mixed evenly. Then, an aqueous solution containing 2.3 g of nitric acid and 4.6 g of oxalic acid was added to the powder and kneaded for 50 minutes to obtain a clump of material. This clump was then extruded into strips to obtain alumina strips containing Co2Mn3O8. The alumina was dried at 100℃ for 5 hours and calcined at 620℃ for 3 hours to obtain alumina carrier A-3 containing Co2Mn3O8.

[0070] Weigh 105.0g of A-3 alumina support, and according to the water absorption rate of the alumina support, weigh and prepare 89g of ammonia solution (the mass ratio of ammonia to water is 4.2:5.8); then weigh 20.9g of ammonium heptamolybdate and 9.2g of cobalt nitrate and add them to the ammonia solution. Spray the above impregnation solution onto the support by spraying to obtain the catalyst precursor. After drying at 130℃ for 4h and calcining at 560℃ for 6h, catalyst A-3 is obtained.

[0071] Example 4

[0072] Preparation of Co2MnO4 and CoMnO3: Unlike Example 1, 248.1g of cobalt nitrate and 130.7g of manganese nitrate were added. Ammonia water was added dropwise to adjust the pH of the solution to 10.9. After the precipitate was formed, it was filtered, washed with water, dried at 90℃ for 8h, and then subjected to high-temperature treatment in a step-by-step process: calcination at 790℃ for 6h and calcination at 650℃ for 5h. This yielded a cobalt-manganese solid solution containing the composite crystal phases of Co2MnO4 and CoMnO3, wherein the proportion of the Co2MnO4 crystal phase in the phase composition of the cobalt-manganese solid solution was ≥50%.

[0073] A mixed slurry was prepared by taking 11.6 g of a cobalt-manganese solid solution with a Co2MnO4 and CoMnO3 composite crystalline phase and 291.5 g of boehmite powder with a particle size of 10 μm. This slurry was then ultrasonically dispersed to obtain a highly dispersed slurry with a particle size of 3 μm. The highly dispersed slurry was centrifuged to obtain a solid material, which was then dried at 110 °C for 3 h to obtain boehmite powder containing the cobalt-manganese solid solution with the Co2MnO4 and CoMnO3 composite crystalline phase.

[0074] 190.0 g of pseudoboehmite powder containing solid solution and 14.9 g of guar gum powder were weighed and added to a kneader and mixed evenly. Then, an aqueous solution containing 4.7 g of nitric acid was added to the powder and kneaded for 25 minutes to obtain a clump of material, which was then extruded into strips to obtain a strip-shaped alumina support containing the Co2MnO4 and CoMnO3 composite crystalline phases. The alumina was dried at 80℃ for 10 h and calcined at 640℃ for 6 h to obtain alumina support A-4 containing the Co2MnO4 and CoMnO3 composite crystalline phases.

[0075] 110.0 g of A-4 alumina support was weighed and a catalyst was prepared by equal-volume impregnation. The water absorption rate of the alumina support was tested, and based on the water absorption rate, 98 g of ammonia solution (mass ratio of ammonia to water was 6:4) was prepared. Then, 5.2 g of ammonium heptamolybdate and 20.0 g of cobalt acetate were weighed and added to the ammonia solution, dissolving them while stirring to obtain a stable impregnation solution. The impregnated support yielded the catalyst precursor, which was dried at 120 °C for 8 h and calcined at 600 °C for 4 h to obtain catalyst A-4.

[0076] Example 5

[0077] The difference from Example 2 is that after adding ammonia water to adjust the pH of the solution to 8.1, the precipitate is filtered, washed with water, dried at 120°C for 3 hours, and calcined at 880°C for 4 hours to obtain a cobalt-manganese solid solution with the molecular formula Co2MnO4.

[0078] A mixed slurry was prepared by taking 12.7g of Co2MnO4 and 350.1g of boehmite powder; then, a highly dispersed slurry with a particle size of 1μm was obtained by ultrasonic dispersion. The highly dispersed slurry was centrifuged to obtain solid material, which was then dried at 100℃ for 6h to obtain boehmite powder containing Co2MnO4.

[0079] The preparation of the alumina carrier differs from that in Example 2 in that 180.0 g of pseudoboehmite powder containing solid solution and 5.7 g of guar gum powder were weighed and added to a kneader and mixed evenly. Then, an aqueous solution containing 10.4 g of citric acid was added to the powder and kneaded for 35 minutes to obtain a clump of material, which was then extruded into strips to finally obtain a strip-shaped alumina carrier containing Co2MnO4. The alumina carrier was then dried at 110℃ for 6 hours and calcined at 550℃ for 8 hours.

[0080] Weigh 110.0g of A-2 alumina support, and according to the water absorption rate of the alumina support, weigh and prepare 94g of ammonia solution (the mass ratio of ammonia to water is 7:3); then weigh 32.1g of ammonium heptamolybdate, 29.9g of cobalt acetate, and 6.9g of nickel acetate and add them to the ammonia solution. Spray the above impregnation solution onto the support by spraying to obtain the catalyst precursor. After drying at 120℃ for 7h and calcining at 630℃ for 5h, catalyst A-5 is obtained.

[0081] Comparative Example 1

[0082] 200.0g of boehmite powder and 4.0g of guar gum powder were weighed and dry-mixed. Then, an aqueous solution containing 2.2g of nitric acid was added to the powder and kneaded for 35 minutes to obtain a clump of material. This clump was then extruded into strips to obtain alumina carriers. The alumina was dried at 90℃ for 8 hours and calcined at 600℃ for 4 hours to obtain alumina carrier B-1.

[0083] 150.0 g of B-1 alumina support was weighed, and the catalyst was prepared by an equal-volume stepwise impregnation method. The water absorption rate of the alumina support was tested, and based on the water absorption rate, 4.3 g of manganese nitrate was weighed and 120 g of manganese nitrate aqueous solution was prepared. The support was impregnated with the solution by equal volume, and dried at 120 °C for 7 h and calcined at 580 °C for 5 h to obtain an intermediate. Then, an ammonia aqueous solution (the mass ratio of ammonia to water was 5.5:4.5) was weighed, and 18.8 g of ammonium heptamolybdate and 65.2 g of cobalt acetate were added to the ammonia aqueous solution. The solution was dissolved while stirring to obtain a stable impregnation solution. The impregnated intermediate was used to obtain the catalyst precursor, which was dried at 120 °C for 7 h and calcined at 580 °C for 5 h to obtain catalyst B-1.

[0084] Comparative Example 2

[0085] Unlike Example 2, 14.3g of Co2MnO4 and 311.2g of boehmite powder with a particle size of 10μm were sequentially added to deionized water. High-speed stirring was required during the addition process to obtain a mixed slurry. This slurry was then dispersed by ball milling to obtain a highly dispersed slurry with a particle size of 3μm. The highly dispersed slurry was centrifuged to obtain a solid material, which was then dried at 120℃ for 4 hours to obtain boehmite powder containing Co2MnO4.

[0086] 180.0 g of pseudoboehmite powder containing solid solution and 6.4 g of guar gum powder were weighed and added to a kneader and mixed evenly. Then, an aqueous solution containing 2.8 g of nitric acid and 2.8 g of citric acid was added to the powder and kneaded for 60 minutes to obtain a clump of material, which was then extruded into strips to obtain alumina carrier containing Co2MnO4. The alumina was dried at 120℃ for 4 hours and calcined at 530℃ for 6 hours to obtain alumina carrier B-2 containing Co2MnO4.

[0087] 56.0 g of B-2 alumina support was weighed and a catalyst was prepared by equal-volume impregnation. The water absorption rate of the alumina support was tested, and based on the water absorption rate, 74 g of ammonia solution (mass ratio of ammonia to water was 3:7) was prepared. Then, 10.6 g of ammonium heptamolybdate and 8.5 g of cobalt nitrate were weighed and added to the ammonia solution, and dissolved while stirring to obtain a stable impregnation solution. The impregnated support yielded the catalyst precursor, which was dried at 150 °C for 4 h and calcined at 650 °C for 4 h to obtain catalyst B-2.

[0088] The selected hydrodesulfurization catalysts A-1, A-2, A-3, A-4, and A-5, and the comparative catalysts B-1 and B-2, achieved desulfurization rates of 88.50%, 92.31%, 90.72%, 86.50%, 91.64%, and 84.01%, 85.32%, respectively; olefin saturation rates of 16.34%, 15.05%, 15.91%, 13.89%, 15.44%, and 18.12%, 16.83%, respectively; and octane number losses of 1.3 units, 1.1 units, 1.3 units, 1.1 units, 1.2 units, and 1.5 units, 1.4 units, respectively. The hydrodesulfurization catalysts prepared on alumina supports containing the cobalt-manganese solid solution described in this invention exhibit high hydrodesulfurization activity, low olefin saturation, good catalyst hydrogenation selectivity, and low octane number (RON) loss during hydrotreating. The cobalt content in the alumina support, calculated as oxide, is lower than that of the Co supported on the catalyst, which helps to improve the dispersibility of the active components on the support surface, increase the utilization rate of the active components, and improve the catalyst stability. In Example 2, after a 1000-hour stability evaluation test, the average desulfurization rate of the product was 92.80%, the olefin saturation rate was 14.93%, and the octane number loss was 1.0 unit. During operation, the temperature increase rate was gradual, increasing by 1-2°C in the first 500 hours and only 2-3°C in the following 500 hours. In contrast, the comparative hydrodesulfurization catalyst B-1, after a 1000-hour evaluation, had an average desulfurization rate of 83.47%, an olefin saturation rate of 18.26%, and an RON loss of 1.5 units. During operation, no temperature increase was observed in the first 500 hours, and only 3-5°C was increased in the following 500 hours.

[0089] The cobalt-manganese solid solution-containing hydrodesulfurization catalyst provided by this invention is beneficial for controlling the size of cobalt grains, effectively controlling the rapid aggregation and growth of cobalt grains when the catalyst is directly loaded with cobalt grains, thereby affecting its modification effect on the main active component. Simultaneously, it improves metal utilization, reduces the amount of active component used, better exerts its synergistic effect on the main active component, improves the hydrodesulfurization activity and selectivity of the selective hydrotreating catalyst, ensures balanced activity release during the reaction process, and enhances catalyst stability.

[0090] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A hydrodesulfurization catalyst, characterized in that, The catalyst component comprises, in 100 parts, 70-98 parts alumina support, 0.5-20 parts group VIB metal oxide and 0.1-10 parts group VIII metal oxide, wherein the group VIII metal oxide includes oxides of Co; and the mass of Co in the alumina support is lower than that of Co supported on the catalyst, based on oxides. The alumina support, based on 100% of its total weight, comprises 0.5-5% cobalt-manganese solid solution, wherein the cobalt-manganese solid solution includes Co. 1.8 Mn 1.2 One or more of O4, CoMn2O4, Co2MnO4, CoMnO3, and Co2Mn3O8; The cobalt-manganese solid solution is prepared by the following method: adding ammonia dropwise to a mixed solution of cobalt nitrate and manganese nitrate while stirring, adjusting the pH of the solution to 8-11 to obtain a precipitate; filtering, washing with water, drying, and calcining at 500-1100℃ for 2-6 hours to obtain the cobalt-manganese solid solution. The method for preparing the alumina support includes the following steps: (1) Pretreatment of powder: Take cobalt-manganese solid solution with a particle size of less than 10 μm and alumina powder, add water and stir to prepare slurry, disperse the slurry to control the particle size of the slurry to less than 5 μm; separate the liquid and solid of the slurry, and dry the solid to obtain alumina powder containing cobalt-manganese solid solution; (2) Carrier molding: Alumina powder containing cobalt-manganese solid solution and extrusion aid are dry-mixed, then mixed with adhesive solvent and water, and extruded into strips; (3) Heat treatment of the carrier: The molded carrier is dried and calcined at a temperature of 500~650℃ for 4~8 hours to obtain an alumina carrier containing cobalt-manganese solid solution.

2. The hydrodesulfurization catalyst according to claim 1, characterized in that, Group VIB metal oxides include tungsten oxide and / or molybdenum oxide, and the Group VIII metal oxides also include nickel oxide.

3. The hydrodesulfurization catalyst according to claim 1, characterized in that, The catalyst component comprises, in 100 parts, 80-95 parts alumina support, 4-15 parts group VIB metal oxide and 0.5-6 parts group VIII metal oxide.

4. The hydrodesulfurization catalyst according to claim 1, characterized in that, The cobalt-manganese solid solution contains cubic Co2MnO4.

5. The hydrodesulfurization catalyst according to claim 1, characterized in that, The proportion of the Co2MnO4 crystalline phase in the phase composition is greater than or equal to 50%.

6. The hydrodesulfurization catalyst according to claim 1, characterized in that, The adhesive solvent is an acid, and the amount of adhesive solvent used is 1 to 10% of the mass of the cobalt-manganese solid solution alumina powder.

7. The hydrodesulfurization catalyst according to claim 1, characterized in that, The amount of the adhesive solvent used is 1 to 5% of the mass of the cobalt-manganese solid solution alumina powder.

8. The hydrodesulfurization catalyst according to claim 6 or 7, characterized in that, The colloidal solvent is one or more of oxalic acid, citric acid, nitric acid, and hydrochloric acid.

9. The hydrodesulfurization catalyst according to claim 1, characterized in that, The extrusion aid is guar gum powder, and the dosage is 2-10% of the mass of the cobalt-manganese solid solution alumina powder.

10. The hydrodesulfurization catalyst according to claim 1, characterized in that, The amount of the extrusion aid is 3-7% of the mass of the cobalt-manganese solid solution alumina powder.

11. The method for preparing the hydrodesulfurization catalyst according to any one of claims 1 to 10, characterized in that, Includes the following steps: (1) Weigh out the group VIB metal precursor salt and the group VIII metal precursor salt, and test the saturated water absorption rate of the alumina support to determine the amount of dissolved water of the metal precursor salt. (2) Add group VIB metal precursor salt and group VIII metal precursor salt to deionized water, and adjust the pH value by introducing ammonia water so that the group VIB metal precursor salt and group VIII metal precursor salt are completely dissolved into a stable mixed solution. (3) The mixed solution is sprayed onto the alumina support in the form of a mist by spraying to obtain the catalyst precursor; (4) Dry the catalyst precursor and calcine it at 550~650℃ for 4~8 hours.

Images