Alumina support, method for preparing the same, and pre-hydrogenation catalyst comprising the same

Abstract

The application discloses an alumina carrier and a preparation method thereof, and a pre-hydrogenation catalyst containing the alumina carrier, the alumina carrier comprising 0.5-12% of a nickel-manganese solid solution and the balance of alumina, based on 100% of the weight of the alumina carrier; the nickel-manganese solid solution is Ni x Mn y O z , wherein 1<=x<=10, 1<=y<=5, 1<=z<=10, and can be one or more of NiMnO3, NiMn2O4 and Ni6MnO8. The pre-hydrogenation catalyst can improve the heavy sulfur conversion activity and the hydrogenation selectivity of dienes, and reduce the RON loss when applied to a catalytic gasoline pre-hydrogenation treatment process; meanwhile, the pre-hydrogenation catalyst can inhibit the polymerization of unsaturated hydrocarbons, especially dienes, during the pre-hydrogenation reaction process, thereby delaying the catalyst deactivation caused by the coking of unsaturated hydrocarbons during the hydrogenation process.

Description

Technical Field

[0001] This invention relates to a catalytic material and a pre-hydrogenation catalyst containing the catalytic material, specifically to an alumina support and its preparation method, and a pre-hydrogenation catalyst containing the alumina support. Background Technology

[0002] To reduce air pollution from vehicle exhaust emissions, my country has accelerated the pace of gasoline quality upgrades. my country's gasoline pool is dominated by catalytic cracking (FCC) gasoline, which is high in sulfur and olefins. Therefore, the key to domestic gasoline clean production technology lies in significantly reducing the sulfur and olefin content of FCC gasoline while minimizing octane number loss. In recent years, in response to the continuous upgrading of gasoline quality, a variety of domestic FCC gasoline clean production technologies have emerged, including selective hydrodesulfurization technology, represented by processes such as Prime-G+, SCAN Fining, and CDHydro / CDHDS; hydrodesulfurization-octane number recovery technology, represented by processes such as OCT-GAIN, RIDOS, and GARDES; and non-hydrodesulfurization technology, represented by processes such as S-Zorb. To date, selective hydrodesulfurization (SHD) technology, as one of the key technical routes for cleaner gasoline production in the FCC, includes a pretreatment reaction unit in its processes. The main function of this unit is to achieve the transfer of light thiols to heavier forms, while selectively removing dienes to prevent the hydrotreating catalyst in subsequent reaction units from deactivating due to rapid coking. The pretreatment catalyst is crucial to this reaction unit, directly affecting the quality of the light gasoline after the fuel-fuel separation process and the stability of the catalysts used in subsequent reaction units. Therefore, research on this catalyst is of great significance.

[0003] US6692635 describes a low-sulfur gasoline production process. Its key feature is that the full-fraction catalytic gasoline feedstock first undergoes thiol re-tightening to high-boiling-point sulfides, selective removal of dienes, and olefin double bond isomerization in a selective hydrotreating reactor. Then, the selective hydrotreating product is fractionated into light and heavy fractions in a fractionating column. The heavy fraction is sequentially hydrogenated on a MoO3-CoO / Al2O3 catalyst in the first reaction zone of the hydrotreating reactor, converting unsaturated sulfides (such as thiophene and its recalcitrant substituted thiophenes) into saturated sulfides (such as tetrahydrothiophene or thiols). Subsequently, it is hydrogenated on a NiO / Al2O3 catalyst in the second reaction zone, converting the saturated sulfides into H2S. The desulfurization rate of the method provided by this patent is typically 80.0%–92.0%, the sulfur content of the product is 96 mg / kg–240 mg / kg, and the research octane number (RON) loss is 1.4–3.0 units. The drawback of the method provided by this patent is that its raw materials are only suitable for low-sulfur gasoline. For raw materials with higher sulfur content, it is difficult to meet the high gasoline quality standards using this method.

[0004] CN201310681690.7 discloses a Pb-Al based hydrotalcite-like desulfurization catalyst, wherein the Pb / Al composite metal oxide is the main active component, with a molar ratio of Pb:Al = 5 to 20:5, or further metal elements are added to the Pb / Al base to form a new multi-component hydrotalcite-like catalyst. For a feedstock with a mercaptan content of 0.15%, an air flow rate of 2.8 L / min, a 15-minute aeration period, and a catalyst dosage of 1% to 6%, the mercaptan content after desulfurization is 0.02 wt% to 0.11 wt%, and the desulfurization rate is 27% to 87%. However, this catalyst exhibits relatively weak desulfurization activity, and after three cycles, the catalyst solid particle size becomes finer, leading to catalyst loss and affecting its service life.

[0005] CN200910187903.4 discloses a hydrodesulfurization catalyst, its preparation method, and its application. The catalyst uses HSM-5 molecular sieve as the main support component and copper and zinc as active components. The active components, by weight of oxides, contain 5%–27% copper oxide and 3%–15% zinc oxide, and are prepared using a saturated co-impregnation technique. This catalyst is suitable for the selective hydrodesulfurization reaction of light oil products, exhibiting high desulfurization activity and low olefin hydrogenation activity, along with high liquid yield and minimal octane number loss. However, the low olefin hydrogenation activity directly affects the diene hydrogenation activity, leading to coking of the subsequent catalyst and impacting long-term operation of the unit.

[0006] CN201610701753.4 discloses a dethiol catalyst, its preparation method, and its application. The catalyst comprises a support, an active component, and an oxidizing agent, a heteropolyacid. The support is composed of alumina and a molecular sieve modified with rare earth elements. The active component is one or more metal oxides selected from Group IA, IIA, IB, IIB, VIIB, or VIII. The catalyst of this invention modifies the molecular sieve, altering its pore structure and adsorption properties, thereby enhancing the chemisorption capacity of the catalyst support for thiols, making it more conducive to thiols adsorption. Simultaneously, the catalyst utilizes the strong oxidizing properties of the heteropolyacid to oxidize thiols to their corresponding disulfides, which are then adsorbed by the composite support of this invention. This allows the dethiol catalyst of this invention to remove thiols without the need for hydrogenation while simultaneously reducing the total sulfur content, achieving complete dethiol removal. However, this technology performs adsorption-oxidative dethiol removal in a non-hydrogenation environment and cannot selectively hydrogenate olefins; therefore, its function is limited, and its application is restricted.

[0007] CN 201610561945.X discloses a thiol etherification catalyst and its preparation method. The catalyst consists of 75%–85% NiO-SiO2 powder, 5%–10% NiO, and the balance Al2O3. The powder is mixed evenly with nitric acid solution, extruded into strips, dried, and calcined to obtain the catalyst. The NiO-SiO2 powder is prepared by a sol-gel method. The thiol etherification catalyst provided by this invention has abundant weakly acidic sites, high thiol etherification activity and high stability, and high selectivity, but it is not suitable for the process conditions described in this invention. CN 201710408085.0 discloses a method for desulfurization of FCC gasoline, using a fixed-bed reactor. The catalyst includes an alumina support with a macroporous structure and metallic active components nickel and molybdenum supported on the support. The alumina support with a macroporous structure comprises 66–91 wt% by weight. Chitosan is used as the pore-expanding agent in the alumina support. The support contains auxiliary components phosphorus and magnesium, with nickel oxide content of 5–19 wt% and molybdenum oxide content of 2–15 wt%. The reaction process conditions are relatively harsh, with a temperature of 110–220℃, a hydrogen pressure of 1.1–3.5 MPa, and a space velocity of 1.2–4.0 h⁻¹. -1 The hydrogen-to-oil ratio is 7–25:1, and the mercaptan removal rate of the catalyst is greater than 85%.

[0008] The aforementioned patents have achieved efficient conversion of thiols through continuous improvements to the carrier and catalyst. However, they have also exposed some problems, such as poor catalyst stability and the inability to simultaneously perform the functions of thiols removal and selective hydrogenation of dienes. This has brought certain limitations to the application of the catalyst, especially in the field of selective hydrogenation desulfurization of catalytic gasoline. Since the catalyst cannot simultaneously perform selective hydrogenation of dienes, it will accelerate the coking and deactivation rate of the subsequent catalyst and affect the application effect of the complete set of technologies.

[0009] CN96109509.1 discloses a light gasoline pre-etherification hydrodediolefin technology, involving a palladium catalyst supported on a macroporous cation exchange resin, and conducting the hydrodediolefin reaction in an expanded bed reactor. The conditions are 70°C, hydrogen pressure 1.5 MPa, hydrogen / diolefin molar ratio 3:1, and space velocity 3 h⁻¹. -1 Under the specified conditions, the diene conversion rate is 97%, demonstrating excellent catalytic activity. However, during the reaction, the main active hydrogenation component, the noble metal palladium, is easily lost, thus affecting the catalyst's operational life.

[0010] CN200410029865.7 discloses a method for selective hydrogenation removal of diolefins. This method involves contacting distillate oil with a catalyst under a hydrorefining process. The catalyst uses alumina as a support, and the active components are one or more of cobalt, nickel, molybdenum, and tungsten, as well as an alkali metal. Its main characteristic is that the atomic ratio of the alkali metal to cobalt or nickel is 1.3–6:1. When the feed oil diolefin content is 1.8–1.9 gI / 100g, the product oil diolefin content is 0.5–1.0 g / 100g. The catalyst achieves a diolefin hydrogenation saturation rate of up to 72%, but the diolefin removal rate is relatively low.

[0011] In summary, the existing catalysts for the conversion of light sulfur and selective hydrogenation of dienes are affected by the support formulation and the proportion of supported metals, resulting in relatively low activities for thiol conversion and diene removal. Therefore, it is necessary to provide a catalyst to improve the thiol conversion rate and diene hydrogenation selectivity. Summary of the Invention

[0012] The purpose of this invention is to provide an alumina support and its preparation method, as well as a pre-hydrogenation catalyst containing the alumina support. The pre-hydrogenation catalyst of this invention can improve the ability of catalytic gasoline to re-titrate small molecule thiols and the hydrogenation selectivity of dienes during pretreatment, reduce RON loss, and delay catalyst deactivation caused by coking of unsaturated hydrocarbons during hydrogenation.

[0013] To achieve the above objectives, the present invention provides an alumina carrier, wherein the alumina carrier comprises 0.5 to 12% nickel-manganese solid solution and the balance alumina, based on 100% by weight of the alumina carrier.

[0014] Preferably, in the alumina carrier of the present invention, the content of the nickel-manganese solid solution is 3-7% based on 100% by weight of the alumina carrier.

[0015] Preferably, in this invention, the nickel-manganese solid solution of the alumina carrier is Ni. x Mn y O z Where 1≤x≤10, 1≤y≤5, 1≤z≤10, and more preferably, 1≤x≤7, 0.5≤y≤3, 2≤z≤9.

[0016] In the alumina carrier of the present invention, preferably, the nickel-manganese solid solution includes one or more of NiMnO3, NiMn2O4, and Ni6MnO8.

[0017] The alumina carrier of the present invention has a nickel-manganese solid solution with crystalline phase characteristics. The crystalline phase characteristics refer to the ability to detect the main characteristic peaks belonging to the nickel-manganese solid solution when the nickel-manganese solid solution is subjected to X-ray diffraction testing.

[0018] The alumina support of the present invention preferably contains Ni6MnO8 with a face-centered cubic lattice in the nickel-manganese solid solution. The crystal phase characteristics of Ni6MnO8 are determined by X-ray diffraction testing and comparison with an X-ray standard card library, which shows that it has characteristic diffraction peaks at 18.5°, 21.3°, 37.4°, 43.5°, 63.2°, 75.8°, and 79.8°.

[0019] The alumina carrier of the present invention, wherein the crystal phase composition of the nickel-manganese solid solution is mainly controlled by the synthesis process, including factors such as composition ratio and high-temperature heat treatment. The preparation method of the nickel-manganese solid solution can be as follows: dissolving nickel and manganese precursors in deionized water to obtain a mixed solution; gradually adding ammonia water dropwise to the mixed solution while stirring; adjusting the pH of the solution to 8-11 to obtain a precipitate; filtering and washing the precipitate; then drying it at 80-150℃ for 2-10 hours and calcining it at 650-1250℃ for 2-6 hours to obtain the nickel-manganese solid solution.

[0020] In the preparation of the nickel-manganese solid solution, the nickel and manganese in the alumina carrier of the present invention can be added in the form of at least one of their nitrates, carbonates and halides, but the present invention is not particularly limited to this.

[0021] The alumina carrier of the present invention is selected from one or more of sodium aluminate, boehmite, and alumina sol, preferably boehmite.

[0022] This invention also provides a method for preparing an alumina support, the method comprising the following steps:

[0023] (1) Hydrothermal treatment of powder: First, alumina and water are mixed evenly; then hydrothermal treatment is carried out, the solid product is filtered out, dried and calcined, and then the hydrothermally treated alumina powder is obtained by grinding and sieving.

[0024] (2) Pretreatment of powder: Take nickel-manganese solid solution with a particle size of less than 8 μm and hydrothermally treated alumina powder, add water and stir to prepare slurry, and then control the particle size of the slurry to below 3 μm by dispersion technology; the slurry is separated into liquid and solid, and the solid is dried to obtain alumina powder containing nickel-manganese solid solution;

[0025] (3) Preparation of carrier: Alumina powder containing nickel-manganese solid solution is dry mixed with extrusion aid, then kneaded with adhesive and water and extruded into shape; the shaped carrier is aged, dried and calcined to obtain alumina carrier.

[0026] In the preparation method of the alumina carrier of the present invention, in step (1), the mass ratio of water to alumina is 1:1 to 10, preferably 1:2 to 4.

[0027] In the preparation method of the alumina carrier of the present invention, in step (1), the hydrothermal treatment temperature is 110-250°C, preferably 130-200°C, and the hydrothermal treatment time is 3-15 hours, preferably 4-8 hours; the drying temperature is 100-150°C, and the time is 4-8 hours; the calcination temperature is 450-600°C, and the time is 2-6 hours.

[0028] The method for preparing the alumina carrier of the present invention includes, but is not limited to, grinding, ball milling, etc. The present invention does not particularly limit grinding, as long as the effect can meet the requirements of the present invention.

[0029] The method for preparing the alumina carrier of the present invention includes, but is not limited to, ball milling dispersion, ultrasonic dispersion, etc. The present invention does not particularly limit the dispersion technology, as long as its effect can meet the particle size requirements of the present invention.

[0030] The method for preparing the alumina carrier of the present invention includes, but is not limited to, at least one of guar gum powder, starch, and methylcellulose, preferably guar gum powder, in an amount of 2-10% of the mass of the alumina carrier, preferably 3-7%.

[0031] The method for preparing the alumina carrier of the present invention uses an acid as the solvent, which can be at least one of organic or inorganic acids, preferably at least one of oxalic acid, citric acid, nitric acid, and hydrochloric acid. The amount of the solvent used is 1-10% of the mass of the alumina carrier, preferably 1-5%.

[0032] In the preparation method of the alumina carrier of the present invention, in step (3), the drying temperature is 80-150°C and the time is 2-10 hours; the calcination temperature is 500-650°C and the time is 4-8 hours.

[0033] The present invention also provides a pre-hydrogenation catalyst, the pre-hydrogenation catalyst comprising a group VIB metal, a group VIII metal, and an alumina support; the group VIII metal includes nickel, the nickel being based on the mass of oxide, and the mass content of nickel oxide in the alumina support is lower than the mass content of nickel oxide supported on the catalyst.

[0034] The pre-hydrogenation catalyst of the present invention, calculated based on 100 parts of catalyst components, comprises 2 to 15 parts of Group VIB metal (based on its oxide), preferably 4 to 12 parts; 4 to 20 parts of Group VIII metal (based on its oxide), preferably 8 to 17 parts; and 65 to 94 parts of alumina support, preferably 70 to 85 parts.

[0035] The pre-hydrogenation catalyst of the present invention comprises a Group VIB metal, which is tungsten and / or molybdenum; and a Group VIII metal, which includes cobalt in addition to nickel.

[0036] The preparation method of the pre-hydrogenation catalyst of the present invention is not particularly limited to the preparation method. The following method can be used: preparing a precursor salt of a group VIB metal or a group VIII metal into an impregnation solution and supporting it on an alumina support to obtain a catalyst precursor; aging, drying and calcining the catalyst precursor to obtain the pre-hydrogenation catalyst.

[0037] The method for preparing the pre-hydrogenated catalyst of the present invention includes, but is not limited to, at least one of the following methods: equal volume impregnation, spraying, and excess impregnation; preferably, the spraying method, which includes, but is not limited to, spraying the precursor salt impregnation solution into a mist onto the alumina support in a rotating drum environment.

[0038] The preparation method of the pre-hydrogenation catalyst of the present invention includes, for example but not limited to, the preparation method of the precursor salt impregnation solution of Group VIB and Group VIII metals as follows: First, the precursor salts of Group VIB and Group VIII metals are weighed according to the catalyst formula, and the saturated water absorption rate of the alumina support used in the catalyst is tested to determine the amount of dissolved water of the metal precursor salts; then, the precursor salts are added sequentially to deionized water, and the pH value is adjusted by introducing concentrated ammonia water, for example, 25% by mass, so that all the precursor salts are dissolved into a stable mixed solution.

[0039] The preparation method of the pre-hydrogenation catalyst of the present invention includes drying and calcination conditions, for example but not limited to: drying at 120-150°C for 4-8 hours and high-temperature treatment at 550-650°C for 4-8 hours.

[0040] In the preparation method of the pre-hydrogenation catalyst of the present invention, both Group VIB metals and Group VIII metals can be introduced as precursor salts in the form of metal halides, nitrates and carbonates. These precursor salts can be decomposed into metal oxides during subsequent high-temperature treatment.

[0041] Compared with the prior art, the present invention has at least the following beneficial effects:

[0042] The alumina support used in this invention contains a nickel-manganese solid solution. The pre-hydrogenation catalyst containing this alumina support introduces metallic nickel in different forms at different stages of catalyst preparation, effectively improving the dispersibility of nickel grains and avoiding grain agglomeration and growth caused by high nickel content, thereby enhancing the nickel's additive effect. It is precisely because of this high nickel grain dispersion that the distribution of nickel oxide on the entire catalyst can be controlled through the preparation method of this invention; that is, the nickel oxide content in the alumina support is lower than the nickel oxide content loaded on the catalyst surface.

[0043] The pre-hydrogenation catalyst of this invention can improve the ability of catalytic gasoline to re-titrate small molecule thiols and the hydrogenation selectivity of dienes during the pretreatment process, and reduce RON loss; at the same time, it plays a role in inhibiting the polymerization of unsaturated hydrocarbons, especially dienes, during the pre-hydrogenation reaction, and delays the catalyst deactivation caused by coking of unsaturated hydrocarbons during the hydrogenation process. Attached Figure Description

[0044] Figure 1 The image shows the XRD pattern of the alumina support sample containing a nickel-manganese solid solution prepared in Example 1. The XRD pattern reveals characteristic peaks of both nickel-manganese solid solution and γ-Al₂O₃, indicating that the alumina support is an alumina material containing a nickel-manganese solid solution. Detailed Implementation

[0045] 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.

[0046] To further illustrate the effects of the method and catalyst used in this invention, examples are given using the pre-hydrogenation catalyst comprising a nickel-manganese solid solution prepared in this invention and the corresponding FCC full-fraction gasoline pre-hydrogenation reaction. However, this invention is not limited to the following examples.

[0047] Sources of raw materials used in the preparation of the support and catalyst:

[0048] All raw materials and reagents used in this invention are commercially available products.

[0049] Sources of raw materials used in the pre-hydrogenation reaction:

[0050] This invention uses FCC full-fraction gasoline as raw material, with a mercaptan content of 48.5 mg / kg, a diene content of 1.67 gI / 100g, an olefin content of 33.52 v%, and a research octane number (RON) of 89.9.

[0051] Analytical methods for catalysts, reactants, and products during the pre-hydrogenation reaction:

[0052] The thiol content of the oil products described in this invention was analyzed using a 916Ti-Touch potentiometric titrator. Diene values ​​were analyzed according to UOP 326-2008. 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.

[0053] The product thiol removal rate, diene conversion rate, and research octane number (RON) loss are calculated using the following formulas:

[0054]

[0055]

[0056] Research Octane Number (RON) Loss = Research Octane Number of Reactants - Research Octane Number of Reactants

[0057] Example 1

[0058] Preparation of Ni6MnO8: Nickel acetate and manganese dichloride are dissolved in deionized water to prepare a mixed solution containing nickel and manganese. Ammonia water is added dropwise to this solution while stirring, and the pH of the solution is adjusted to 8.4. This process will produce a precipitate, which is then filtered, washed with water, dried at 125℃ for 6 hours, and calcined at 1050℃ for 4 hours to obtain the nickel-manganese solid solution Ni6MnO8.

[0059] Preparation of alumina carrier: First, aluminum sol and water were mixed evenly at a mass ratio of 1:2.2. Then, the mixture was hydrothermally treated at 170℃ for 4 hours. The solid product was filtered out, dried at 130℃ for 5 hours, and calcined at 590℃ for 3 hours. The resulting powder was obtained by ball milling and sieving. Ni6MnO8 and the hydrothermally treated powder were mixed, and water was added and stirred to obtain a homogeneous slurry. The slurry was then ultrasonically dispersed, centrifuged, and dried to obtain alumina powder containing Ni6MnO8. The alumina powder containing Ni6MnO8 and guar gum powder were added to a mixer and mixed evenly. Then, an aqueous solution of oxalic acid was introduced and kneaded to obtain agglomerated material. This material was then extruded, dried at 140℃ for 3 hours, and calcined at 530℃ for 5 hours to finally obtain alumina carrier A-1 containing Ni6MnO8. The components and contents of alumina carrier A-1 are shown in Table 1.

[0060] Ammonium heptamolybdate and nickel acetate were dissolved in an ammonia solution to prepare a completely dissolved active component impregnation solution. At room temperature, an excess of the active component impregnation solution was applied to alumina support A-1 to obtain a catalyst precursor. This precursor was aged at room temperature for 3 hours, dried at 125°C for 5.5 hours, and calcined at 570°C for 4 hours to obtain pre-hydrogenation catalyst C-1. The components and their contents in pre-hydrogenation catalyst C-1 are shown in Table 2.

[0061] Example 2

[0062] Preparation of NiMnO3 / Ni6MnO8: Nickel nitrate and manganese nitrate are dissolved in deionized water to prepare a mixed solution containing nickel and manganese. Ammonia water is added dropwise to this solution while stirring, and the pH of the solution is adjusted to 10.8. This process will produce a precipitate, which is then filtered, washed with water, dried at 90℃ for 5 hours, calcined at 750℃ for 3 hours, and calcined at 980℃ for 4.5 hours to obtain the nickel-manganese solid solution NiMnO3 / Ni6MnO8.

[0063] Preparation of alumina support: First, boehmite and water were mixed evenly at a mass ratio of 1:3.6, and then hydrothermally treated at 220℃ for 6 hours. The solid product was filtered out, dried at 110℃ for 7 hours, and calcined at 500℃ for 5 hours. The hydrothermally treated powder was obtained by grinding and sieving. NiMnO3 / Ni6MnO8 was mixed with the hydrothermally treated powder, and water was added and stirred to prepare a uniform slurry. Then, alumina powder containing NiMnO3 / Ni6MnO8 was obtained by ultrasonic dispersion, centrifugation, and drying. The alumina powder containing NiMnO3 / Ni6MnO8 and starch were added to a mixer and mixed evenly. Then, an aqueous solution of nitric acid was introduced into the mixture and kneaded to obtain agglomerated material. After extrusion molding, the mixture was dried at 110℃ for 5 hours and calcined at 500℃ for 4 hours to finally obtain alumina support A-2 containing NiMnO3 / Ni6MnO8. The components and contents of alumina support A-2 are shown in Table 1.

[0064] Ammonium heptamolybdate and nickel nitrate were dissolved in an ammonia solution to prepare a completely dissolved active component impregnation solution. At room temperature, the active component impregnation solution was sprayed as a mist onto alumina support A-2 in a rotating drum environment to obtain a catalyst precursor. After aging at room temperature for 6 hours, it was dried at 140℃ for 4 hours and calcined at 640℃ for 5 hours to obtain pre-hydrogenation catalyst C-2. The components and contents of pre-hydrogenation catalyst C-2 are shown in Table 2.

[0065] Example 3

[0066] Preparation of NiMnO3: Nickel chloride and manganese acetate are dissolved in deionized water to prepare a mixed solution containing nickel and manganese. Ammonia water is added dropwise to the solution while stirring, and the pH of the solution is adjusted to 9.5. This process will produce a precipitate, which is then filtered, washed with water, dried at 140℃ for 3 hours, and calcined at 690℃ for 5 hours to obtain the nickel-manganese solid solution NiMnO3.

[0067] Preparation of alumina support: First, boehmite and water were mixed evenly at a mass ratio of 1:0.5, and then hydrothermally treated at 135℃ for 8 hours. The solid product was filtered out, dried at 150℃ for 4 hours, and calcined at 450℃ for 6 hours. The resulting powder was obtained by ball milling and sieving. NiMnO3 and the hydrothermally treated powder were mixed, and water was added and stirred to obtain a homogeneous slurry. The slurry was then dispersed by ball milling, centrifuged, and dried to obtain alumina powder containing NiMnO3. The alumina powder containing NiMnO3 and guar gum powder were added to a mixer and mixed evenly. Then, an aqueous solution of citric acid was introduced and kneaded to obtain agglomerated material. This material was then extruded, dried at 130℃ for 6 hours, and calcined at 640℃ for 4 hours to finally obtain alumina support A-3 containing NiMnO3. The components and contents of alumina support A-3 are shown in Table 1.

[0068] Ammonium heptamolybdate, ammonium tungstate, and nickel carbonate were dissolved in an ammonia solution to prepare a completely dissolved active component impregnation solution. This solution was then applied in excess to alumina support A-3 at room temperature to obtain a catalyst precursor. The precursor was aged at room temperature for 4 hours, dried at 135℃ for 6 hours, and calcined at 550℃ for 8 hours to obtain pre-hydrogenation catalyst C-3. The components and their contents in pre-hydrogenation catalyst C-3 are shown in Table 2.

[0069] Example 4

[0070] Preparation of Ni6MnO8: Nickel carbonate and manganese acetate are dissolved in deionized water to prepare a mixed solution containing nickel and manganese. Ammonia water is added dropwise to the solution while stirring, and the pH of the solution is adjusted to 10.2. This process will produce a precipitate, which is then filtered, washed with water, dried at 105℃ for 7 hours, and calcined at 1200℃ for 5 hours to obtain the nickel-manganese solid solution Ni6MnO8.

[0071] Preparation of alumina carrier: First, aluminum sol and water were mixed evenly at a mass ratio of 1:1.3, and then hydrothermally treated at 245℃ for 3 hours. The solid product was filtered out, dried at 100℃ for 6 hours, and calcined at 550℃ for 3 hours. After grinding and sieving, hydrothermally treated powder was obtained. Ni6MnO8 and the hydrothermally treated powder were mixed, water was added and stirred to obtain a uniform slurry. Then, alumina powder containing Ni6MnO8 was obtained by ball milling, centrifugation and drying. The alumina powder containing Ni6MnO8 and methylcellulose were added to a mixer and mixed. After uniform mixing, an aqueous solution of hydrochloric acid was introduced and kneaded to obtain agglomerated material. After extrusion molding, it was dried at 90℃ for 8 hours and calcined at 570℃ for 7 hours to finally obtain alumina carrier A-4 containing Ni6MnO8. The components and contents of alumina carrier A-4 are shown in Table 1.

[0072] Ammonium tungstate, cobalt nitrate, and nickel chloride were dissolved in an ammonia solution to prepare a completely dissolved active component impregnation solution. At room temperature, an equal volume of the active component impregnation solution was impregnated onto alumina support A-4 to obtain a catalyst precursor. This precursor was aged at room temperature for 2 hours, dried at 150℃ for 7.5 hours, and calcined at 610℃ for 6 hours to obtain pre-hydrogenation catalyst C-4. The components and their contents in pre-hydrogenation catalyst C-4 are shown in Table 2.

[0073] Example 5

[0074] Preparation of NiMn2O4: Nickel acetate and manganese nitrate are dissolved in deionized water to prepare a mixed solution containing nickel and manganese. Ammonia water is added dropwise to this solution while stirring, and the pH of the solution is adjusted to 8.9. This process will produce a precipitate, which is then filtered, washed with water, dried at 115℃ for 4 hours, and calcined at 920℃ for 6 hours to obtain the nickel-manganese solid solution NiMn2O4.

[0075] Preparation of alumina carrier: First, sodium aluminate and water at a mass ratio of 1:9.4 were mixed evenly, and then hydrothermally treated at 110℃ for 10h. The solid product was filtered out, dried at 120℃ for 5h, and calcined at 480℃ for 4h. The resulting powder was obtained by ball milling and sieving. NiMn2O4 and the hydrothermally treated powder were mixed, and water was added and stirred to obtain a uniform slurry. The slurry was then ultrasonically dispersed, centrifuged, and dried to obtain alumina powder containing NiMn2O4. The alumina powder containing NiMn2O4 and methylcellulose were added to a mixer and mixed evenly. Then, an aqueous solution of nitric acid and citric acid was introduced and kneaded to obtain agglomerated material. This material was extruded, dried at 120℃ for 4h, and calcined at 610℃ for 8h to finally obtain alumina carrier A-5 containing NiMn2O4. The components and contents of alumina carrier A-5 are shown in Table 1.

[0076] Ammonium heptamolybdate and nickel carbonate were dissolved in an ammonia solution to prepare a completely dissolved active component impregnation solution. At room temperature, the active component impregnation solution was sprayed as a mist onto alumina support A-5 in a rotating drum environment to obtain a catalyst precursor. This precursor was aged at room temperature for 5 hours, dried at 130℃ for 5 hours, and calcined at 630℃ for 4 hours to obtain pre-hydrogenation catalyst C-5. The components and their contents in pre-hydrogenation catalyst C-5 are shown in Table 2.

[0077] Comparative Example 1

[0078] The difference from Example 5 is that the nickel-manganese solid solution NiMn2O4 was not added during the preparation of the alumina support; otherwise, the process was the same as in Example 5, resulting in alumina support B-1 and pre-hydrogenation catalyst C-D1. The components and contents of alumina support B-1 are shown in Table 1, and the components and contents of pre-hydrogenation catalyst C-D1 are shown in Table 2.

[0079] Comparative Example 2

[0080] The difference from Example 5 is that the mass content of nickel oxide in the alumina support is higher than that of nickel oxide supported on the pre-hydrogenated catalyst. The components and contents of the obtained alumina support B-2 are shown in Table 1, and the components and contents of the hydrotreating catalysts C-D2 are shown in Table 2.

[0081] Table 1. Composition and content of alumina carrier

[0082]

[0083] Table 2 Composition and content of pre-hydrogenation catalyst

[0084]

[0085]

[0086] Pre-hydrogenation performance evaluation

[0087] The catalysts obtained in the examples and comparative examples were used to evaluate the performance of the pre-hydrogenation reaction. The pre-hydrogenation reaction process conditions are as follows:

[0088] The pre-hydrogenated catalyst was loaded into a 30 mL fixed isothermal bed reactor for reaction performance evaluation. Prior to evaluation, the pre-hydrogenated 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 dimethyl disulfide as the sulfurizing agent. During sulfurization, the catalyst bed temperature was increased at a rate of 25 °C / h and held at two temperature ranges of 210 °C and 260 °C for 7 h. After the pre-sulfurization process was completed, the reaction operating conditions were adjusted to start-up conditions, and the sulfurized oil was switched to FCC full-range gasoline before entering the reaction stage. The reaction operating conditions were: inlet temperature 125 °C, pressure 2.4 MPa, and volumetric hourly space velocity (VHSV) 2.8 h⁻¹. -1 The hydrogen-to-oil volume ratio is 5:1.

[0089] The pre-hydrogenation reaction performance evaluation results of the catalysts obtained in the examples and comparative examples are shown in Table 3.

[0090] Table 3. Evaluation results of the pre-hydrogenation reaction performance of the catalysts in the examples and comparative examples.

[0091] Catalyst name Thiol removal rate, % Diene conversion, % RON loss C-1 78.94 57.60 0.5 C-2 83.61 62.24 0.3 C-3 81.22 59.86 0.4 C-4 81.75 61.43 0.4 C-5 79.49 57.12 0.6 C-D1 76.93 56.78 0.8 C-D2 77.54 56.92 0.7

[0092] As can be seen from the results of Example 5 and Comparative Examples 1 and 2, the pre-hydrogenation catalyst prepared by the alumina support of the present invention can improve the ability of small molecule thiols to re-tide gasoline and the hydrogenation selectivity of dienes during the pretreatment process, and reduce RON loss; at the same time, it plays a role in inhibiting the polymerization of unsaturated hydrocarbons, especially dienes, during the pre-hydrogenation reaction, and delays the catalyst deactivation caused by coking of unsaturated hydrocarbons during the hydrogenation process.

[0093] Of course, the present invention may have other embodiments and variations. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and variations according to the present invention, but these corresponding changes and variations should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing an alumina carrier, characterized in that, Includes the following steps: (1) Hydrothermal treatment of powder: First, the alumina precursor and water are mixed evenly; then hydrothermal treatment is carried out, the solid product is filtered out, dried, calcined, ground and sieved to obtain hydrothermally treated alumina powder. (2) Pretreatment of powder: Take nickel-manganese solid solution with a particle size of less than 8 μm and hydrothermally treated alumina powder, add water and stir to prepare slurry, disperse, and control the particle size of slurry to below 3 μm; separate the liquid and solid of slurry, dry the solid, and obtain alumina powder containing nickel-manganese solid solution; (3) Preparation of carrier: Alumina powder containing nickel-manganese solid solution is dry mixed with extrusion aid, then kneaded with adhesive and water and extruded into shape; the shaped carrier is aged, dried and calcined to obtain alumina carrier; Based on 100% by weight of the alumina carrier, the alumina carrier comprises 0.5-12% nickel-manganese solid solution and the balance alumina; The alumina precursor is obtained from one or more of sodium aluminate, boehmite, and alumina sol.

2. The preparation method according to claim 1, characterized in that, The content of the nickel-manganese solid solution is 3-7% based on 100% of the weight of the alumina carrier.

3. The preparation method according to claim 1, characterized in that, The nickel-manganese solid solution is Ni x Mn y O z , where 1≤x≤10, 1≤y≤5, 1≤z≤10.

4. The preparation method according to claim 1, characterized in that, The nickel-manganese solid solution is Ni x Mn y O z , where 1≤x≤7, 0.5≤y≤3, 2≤z≤9.

5. The preparation method according to claim 1, characterized in that, The nickel-manganese solid solution is one or more of NiMnO3, NiMn2O4, and Ni6MnO8.

6. The preparation method according to any one of claims 1-5, characterized in that, The nickel-manganese solid solution contains Ni6MnO8 with a face-centered cubic lattice.

7. The preparation method according to claim 1, characterized in that, The alumina precursor was obtained from boehmite.

8. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of water to alumina precursor is 1:1 to 10.

9. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of water to alumina precursor is 1:2~4.

10. The preparation method according to claim 1, characterized in that, In step (1), the temperature of the hydrothermal treatment is 110~250℃ and the time of the hydrothermal treatment is 3~15 hours; the temperature of the drying is 100~150℃ and the time is 4~8 hours; the temperature of the calcination is 450~600℃ and the time of the calcination is 2~6 hours.

11. The preparation method according to claim 10, characterized in that, In step (1), the temperature of the hydrothermal treatment is 130~200℃.

12. The preparation method according to claim 10, characterized in that, In step (1), the hydrothermal treatment time is 4 to 8 hours.

13. The preparation method according to claim 1, characterized in that, The adhesive solvent is at least one of organic acid or inorganic acid.

14. The preparation method according to claim 1, characterized in that, The adhesive solvent is at least one of oxalic acid, citric acid, nitric acid, and hydrochloric acid.

15. The preparation method according to claim 1, characterized in that, The extrusion aid is at least one of guar gum powder, starch, and methylcellulose.

16. The preparation method according to claim 1, characterized in that, In step (3), the drying temperature is 80~150℃ and the drying time is 2~10 hours; the roasting temperature is 500~650℃ and the roasting time is 4~8 hours.

17. A pre-hydrogenation catalyst, characterized in that, The pre-hydrogenation catalyst comprises: a Group VIB metal, a Group VIII metal, and an alumina support; based on 100% by weight of the alumina support, the alumina support comprises 0.5-12% nickel-manganese solid solution and the balance alumina; the Group VIII metal includes nickel, and the nickel content in the alumina support is lower than the mass content of nickel oxide supported on the catalyst, based on the mass of the oxide.

18. The pre-hydrogenation catalyst according to claim 17, characterized in that, The content of the nickel-manganese solid solution is 3-7% based on 100% of the weight of the alumina carrier.

19. The pre-hydrogenation catalyst according to claim 17, characterized in that, The nickel-manganese solid solution is Ni x Mn y O z , where 1≤x≤10, 1≤y≤5, 1≤z≤10.

20. The pre-hydrogenation catalyst according to claim 17, characterized in that, The nickel-manganese solid solution is Ni x Mn y O z , where 1≤x≤7, 0.5≤y≤3, 2≤z≤9.

21. The pre-hydrogenation catalyst according to claim 17, characterized in that, The nickel-manganese solid solution is one or more of NiMnO3, NiMn2O4, and Ni6MnO8.

22. The pre-hydrogenation catalyst according to any one of claims 17-21, characterized in that, The nickel-manganese solid solution contains Ni6MnO8 with a face-centered cubic lattice.

23. The pre-hydrogenation catalyst according to claim 17, characterized in that, The alumina is obtained from one or more of sodium aluminate, boehmite, and aluminosilicate.

24. The pre-hydrogenation catalyst according to claim 17, characterized in that, The alumina was obtained from boehmite.

25. The pre-hydrogenation catalyst according to claim 17, characterized in that, Based on a catalyst component of 100 parts, the amount of the group VIB metal (calculated as its oxide) is 2-15 parts; the amount of the group VIII metal (calculated as its oxide) is 4-20 parts; and the amount of the alumina support is 65-94 parts.

26. The pre-hydrogenation catalyst according to claim 25, characterized in that, Based on a catalyst component of 100 parts, the amount of the group VIB metal, calculated as its oxide, is 4 to 12 parts.

27. The pre-hydrogenation catalyst according to claim 25, characterized in that, Based on a catalyst component of 100 parts, the amount of the Group VIII metal, calculated as its oxide, is 8 to 17 parts.

28. The pre-hydrogenation catalyst according to claim 25, characterized in that, Based on a catalyst component of 100 parts, the amount of alumina support used is 70-85 parts.

29. The pre-hydrogenation catalyst according to claim 17, characterized in that, The group VIB metal is tungsten and / or molybdenum; the group VIII metal is nickel, or nickel and cobalt.

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