A hydrofining catalyst, its preparation method and use

Abstract

The application provides a hydrofining catalyst, and a preparation method thereof, which comprises the following steps: placing a zirconium source, an organic ligand and pseudo-boehmite in a solvent to perform a solvothermal treatment, so as to obtain a Zr-MOF@Al2O3 precursor; performing a calcination treatment, so as to obtain a zirconium-doped macroporous alumina carrier ZrO2@Al2O3; loading at least one metal in a group VIII metal and at least one metal in a group VIB metal onto the ZrO2@Al2O3 carrier by an impregnation method; and after drying and calcination treatment, the hydrofining catalyst is obtained. The MOF material is compounded with the alumina carrier in an in-situ growth mode, the adjustment of the acidic property and the pore property is considered, the adsorption and diffusion of reactants, especially macromolecular reactants such as polycyclic aromatic hydrocarbons, on the catalyst are promoted, and the hydrodepolycyclic aromatic hydrocarbon activity is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogenation catalysts, in particular to a hydrofining catalyst and a preparation method thereof. BACKGROUND

[0002] The excessive aromatic content and the proportion of polycyclic aromatic hydrocarbons in oil products seriously affect the quality of oil products, which can cause incomplete combustion, high natural temperature, and a large amount of PM2.5 in tail gas, thereby causing great threat to the ecological environment. Therefore, researching a hydrofining desulfurization, denitrification, and polycyclic aromatic hydrocarbon removal catalyst suitable for oil product upgrading is the key to solving the above problems.

[0003] CN111569938A proposes a hydrofining catalyst and a preparation method and application thereof. The invention mainly modifies the hierarchical pore molecular sieve TS-1 first, then composites the hierarchical pore molecular sieve TS-1 with alumina to obtain a CoMo / TS-1 / Al2O3 composite material, and then modifies the CoMo / TS-1 / Al2O3 material with lye to obtain a final CoMo type hydrofining catalyst. The catalyst has a hierarchical pore, good dispersion of active components, adjustable acidity, and is used for diesel hydrofining, with a desulfurization rate of more than 99%, a denitrification rate of more than 97%, and a polycyclic aromatic hydrocarbon content of less than 11%. The catalyst obtained by the invention has good desulfurization and denitrification activity, but the de-aromatic activity is insufficient, which cannot meet the existing national VI diesel standard. CN1205316 proposes a preparation of a metal type aromatic hydrocarbon hydrogenation saturation catalyst, with Pt and Pd as active metals. The noble metal has a high price but poor sulfur resistance, and is suitable for ultra-low sulfur raw materials.

[0004] The activity of the existing diesel hydrofining catalyst needs to be improved, and a high-efficiency hydrofining catalyst needs to be developed. SUMMARY

[0005] To meet the requirements of oil product quality upgrading and solve the problems of low hydrogenation depth, insufficient activity, and poor polycyclic aromatic hydrocarbon removal capacity of the existing hydrofining catalyst, the present application provides a hydrofining catalyst and a preparation method thereof. The preparation method of the present application is simple and easy to implement, and the hydrogenation performance of the obtained catalyst, especially the polycyclic aromatic hydrocarbon saturation capacity, is greatly improved.

[0006] To achieve the above technical purposes, the technical solutions adopted by the present application are as follows:

[0007] The present application provides a preparation method of a hydrofining catalyst in the first aspect, comprising the following steps:

[0008] (1) Dissolve a zirconium source and an organic ligand in a solvent, add pseudo-boehmite, mix, and then perform a solvothermal treatment. After the reaction, the product is centrifuged, washed, and dried to obtain a Zr-MOF@Al2O3 precursor;

[0009] (2) calcining the Zr-MOF@Al2O3 precursor to obtain a zirconium-doped macroporous alumina support ZrO2@Al2O3;

[0010] (3) loading at least one metal in Group VIII and at least one metal in Group VIB onto the ZrO2@Al2O3 support by impregnation, and after drying and calcination, obtaining the hydrofining catalyst.

[0011] Further, the zirconium source in step (1) is selected from one or more of zirconium oxychloride, zirconium chloride, zirconium nitrate and zirconium sulfate, preferably zirconium chloride and / or zirconium oxychloride.

[0012] Further, the organic ligand is selected from one or more of benzoic acid, terephthalic acid, trimesic acid, pyromellitic acid, 2-amino-terephthalic acid, succinic acid, fumaric acid and 2,5-thiophenedicarboxylic acid, preferably one or more of benzoic acid, terephthalic acid, trimesic acid and fumaric acid.

[0013] Further, the molar ratio of zirconium to organic ligand in step (1) is 0.01-5:1, preferably 0.015-3:1.

[0014] Further, the amount of pseudoboehmite added in step (1) is 0.002-0.1:1 in terms of the molar ratio of zirconium to aluminum, preferably 0.004-0.075:1, and most preferably 0.01-0.05:1.

[0015] Further, the solvent is selected from one or more of deionized water, formic acid, acetic acid and N,N-dimethylformamide, preferably acetic acid and / or N-dimethylformamide.

[0016] Further, the solvent thermal treatment temperature in step (1) is 80-150°C, preferably 100-130°C, and the thermal treatment time is 8-72h, preferably 24-48h. The reaction pressure is the autogenous pressure in a closed system.

[0017] Further, the drying temperature in step (1) is 50-200°C, preferably 80-150°C, and the drying time is 1-30h, preferably 12-24h. The drying method is ordinary oven drying or vacuum drying, preferably vacuum drying.

[0018] Further, the calcination temperature in step (2) is 400-800°C, preferably 500-750°C, and the calcination time is 1-10h, preferably 3-6h.

[0019] Furthermore, the Group VIII metal mentioned in step (3) is selected from at least one of Fe, Co and Ni, preferably Co and / or Ni; the Group VIB metal is selected from at least one of Mo, W and Cr, preferably Mo and / or W.

[0020] Furthermore, in step (3), based on the total mass of the catalyst, the amount of Group VIII metal fed is such that the mass percentage of the metal in the oxidized state is 2 to 20 wt%, preferably 3 to 12 wt%; and the amount of Group VIB metal fed is such that the mass percentage of the metal in the oxidized state is 8 to 45 wt%, preferably 15 to 40 wt%.

[0021] Furthermore, the zirconium-doped alumina support ZrO2@Al2O3 in the catalyst has a weight content of 35–90 wt%, preferably 58–73 wt%.

[0022] Furthermore, the impregnation method in step (3) involves impregnating the ZrO2@Al2O3 carrier with a solution of Group VIII metal salt and Group VIB metal salt. The Group VIII metal salt is selected from one or more of nitrates, chlorides and acetates, preferably nitrates; the Group VIB metal salt is preferably an ammonium salt.

[0023] Furthermore, the drying temperature in step (3) is 80-150°C, preferably 90-120°C; the calcination temperature is 300-700°C, preferably 350-550°C; and the calcination time is 1-10 hours, preferably 3-6 hours.

[0024] The technical objective of the second aspect of this invention is to provide a hydrorefining catalyst prepared by the above-described preparation method.

[0025] The technical objective of the third aspect of this invention is to provide a method for hydrotreating oil to remove polycyclic aromatic hydrocarbons, wherein the above-mentioned catalyst is reacted with the oil. The reaction conditions are: reaction pressure of 5.0–8.0 MPa; reaction temperature of 320–385 °C; and volume hourly space velocity of 0.5–3 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200–600.

[0026] The technical solution of the present invention has the following technical effects:

[0027] The hydrofining catalyst in the application is compounded by in-situ growth of MOF material and alumina carrier, and the adjustment of acid properties and pore properties is considered to promote the adsorption and diffusion of reactants, especially large molecule reactants such as polycyclic aromatic hydrocarbons, on the catalyst. With the help of the rich functional groups on the active alumina surface, the modifier MOF is uniformly dispersed on the alumina surface by in-situ self-assembly, which can effectively modify the surface properties of the alumina carrier. Meanwhile, the uniform mixing of MOF and alumina makes the pore distribution on the composite carrier more uniform and the pore size distribution more concentrated. The zirconium element is finally combined with alumina in the form of oxidation to form a heterogeneous structure carrier, which can effectively reduce the interaction between the carrier and the active metal, thereby facilitating the generation of II-type active centers in the sulfidation process, and can effectively improve the acid content of the carrier, and finally improve the hydrofining activity. DETAILED DESCRIPTION

[0028] The application will be described in detail below by examples, but the application is not limited to these examples.

[0029] In the following examples, the proportion of elements and the proportion of active metals are calculated by the amount of feed; the specific surface area and pore size are characterized by nitrogen physical adsorption method; and the total acid amount is determined by NH3-TPD method.

[0030] Example 1

[0031] (1) 16 g of zirconium oxychloride and 5.2 g of fumaric acid were added to 260 mL of formic acid / N,N-dimethylformamide (volume ratio 1:3), and after the solid was completely dissolved, 100 g of pseudoboehmite (78% dry basis) was added, and the mixture was stirred magnetically at room temperature for 30 minutes. The mixture was then added to a hydrothermal reactor and treated by solvothermal method at 120℃ for 24 hours. After the reaction was completed, the solid product was centrifuged, washed with DMF several times, and then washed with ethanol several times. The solid was then placed in a vacuum drying oven and dried at 120℃ for 10 hours. The final Zr-MOF / pseudoboehmite composite carrier precursor was obtained. The Zr / Al molar ratio in this process was 0.032.

[0032] (2) The precursor in (1) was calcined at 700℃ to obtain a zirconium-doped large-pore alumina material (ZrO2@Al2O3).

[0033] (3) 35 g of ammonium molybdate and 25 g of nickel nitrate were prepared into an active metal impregnation solution, and the active metal was impregnated onto the ZrO2@Al2O3 carrier by impregnation method, followed by drying at 120℃ for 6 hours and calcination at 460℃ for 5 hours to obtain a hydrofining catalyst A. In catalyst A, the content of nickel oxide was 5.5%, and the content of molybdenum oxide was 24.3%.

[0034] Example 2

[0035] (1) 4.5 g of zirconium oxychloride and 1.50 g of fumaric acid were added to 260 mL of formic acid / N,N-dimethylformamide (volume ratio 1:3), after the solids were completely dissolved, 100 g of pseudoboehmite (78% dry basis) was added, and the mixture was stirred magnetically at room temperature for 30 minutes, and then the mixture was added to a hydrothermal reactor, and was treated by solvothermal method at 120°C for 24 hours. After the reaction was completed, the solid product obtained was centrifuged, washed, washed several times with DMF, and then washed several times with ethanol, and then the solid was placed in a vacuum drying oven and dried for 10 hours at a drying temperature of 120°C, and finally a Zr-MOF / pseudoboehmite composite carrier precursor was obtained. The Zr / Al molar ratio in the process was 0.009.

[0036] (2) The precursor in (1) was calcined at 700°C to obtain a zirconium-doped large-pore alumina material (ZrO2@Al2O3).

[0037] (3) An active metal impregnation solution was prepared by using 34 g of ammonium molybdate and 24.5 g of nickel nitrate, and the active metal was impregnated onto the ZrO2@Al2O3 carrier by impregnation method, followed by drying at 110°C for 8 hours and calcination at 450°C for 6 hours, to obtain a hydrofining catalyst B. In the catalyst B, the content of nickel oxide was 5.6%, and the content of molybdenum oxide was 24.5%.

[0038] Example 3

[0039] (1) 28 g of zirconium oxychloride and 10.5 g of fumaric acid were added to 260 mL of formic acid / N,N-dimethylformamide (volume ratio 1:3), after the solids were completely dissolved, 100 g of pseudoboehmite (78% dry basis) was added, and the mixture was stirred magnetically at room temperature for 30 minutes, and then the mixture was added to a hydrothermal reactor, and was treated by solvothermal method at 120°C for 24 hours. After the reaction was completed, the solid product obtained was centrifuged, washed, washed several times with DMF, and then washed several times with methanol, and then the solid was placed in a vacuum drying oven and dried for 5 hours at a drying temperature of 150°C, and finally a Zr-MOF / pseudoboehmite composite carrier precursor was obtained. The Zr / Al molar ratio in the process was 0.057.

[0040] (2) The precursor in (1) was calcined at 700°C to obtain a zirconium-doped large-pore alumina material (ZrO2@Al2O3).

[0041] (3) 36 g ammonium molybdate, 26 g nickel nitrate were prepared into active metal impregnation solution, active metals were impregnated onto ZrO2@Al2O3 carrier by impregnation method, then dried at 110 ℃ for 8 hours, calcined at 450 ℃ for 6 hours, to obtain hydrofining catalyst C. In catalyst C, the content of nickel oxide was 5.5%, and the content of molybdenum oxide was 24.0%.

[0042] Example 4

[0043] (1) 1.5 g zirconium oxychloride and 0.5 g fumaric acid were added into 260 mL formic acid / N, N-dimethylformamide (volume ratio 1:3), after the solid was completely dissolved, 100 g pseudo-boehmite (78% dry basis) was added, and the mixture was stirred at room temperature for 30 minutes, and then the mixture was added into a hydrothermal reactor and treated by solvothermal method at 120 ℃ for 24 hours. After the reaction was completed, the obtained solid product was centrifuged, washed, washed several times with DMF, and then washed several times with methanol, and then the solid was placed in a vacuum drying oven and dried at 150 ℃ for 5 hours, to obtain a Zr-MOF / pseudo-boehmite composite carrier precursor. In this process, the Zr / Al molar ratio of the raw materials was 0.003.

[0044] (2) The precursor in (1) was calcined at 700 ℃ to obtain a zirconium-doped large-pore alumina material (ZrO2@Al2O3).

[0045] (3) 35 g ammonium molybdate, 25 g nickel nitrate were prepared into active metal impregnation solution, active metals were impregnated onto ZrO2@Al2O3 carrier by impregnation method, then dried at 130 ℃ for 4 hours, calcined at 450 ℃ for 6 hours, to obtain hydrofining catalyst D. In catalyst D, the content of nickel oxide was 5.7%, and the content of molybdenum oxide was 25.1%.

[0046] Comparative Example 1

[0047] 100 g pseudo-boehmite (dry basis 78%) was calcined at 700 ℃ for 3 h. Active metals Mo and Ni were impregnated onto the prepared carrier by impregnation method, in the impregnation solution, 35 g ammonium heptamolybdate tetrahydrate was added, and 25 g nickel nitrate hexahydrate was added, then dried at 120 ℃ for 6 hours, and calcined at 460 ℃ for 5 hours, to obtain catalyst E. In catalyst E, the mass content of nickel oxide was 5.7%, and the mass content of molybdenum oxide was 25.3%.

[0048] Comparative Example 2

[0049] Zirconium oxychloride 12.1 g and 100 g of pseudo-boehmite (dry basis 78%) were mechanically mixed uniformly (wherein the molar ratio of Zr / Al was 0.025) and calcined at 700°C for 3 h. Active metals Mo and Ni were impregnated onto the prepared carrier by impregnation method, and the raw materials were fed in the impregnation solution as follows: 33 g of ammonium molybdate, 25 g of nickel nitrate, followed by drying at 120°C for 6 h and calcination at 450°C for 4 h to obtain catalyst F. In catalyst F, the content of nickel oxide was 5.3%, and the content of molybdenum oxide was 23.2%.

[0050] The properties of each catalyst are shown in Table 1.

[0051] Table 1

[0052] Catalyst A B C D E F Specific surface area, m 2 / g]] 282 265 296 248 234 228 Average pore diameter, nm 8.98 7.41 14.3 6.45 5.83 4.54 Total acid amount, mmol / g 0.492 0.441 0.501 0.411 0.371 0.404

[0053] Example 5

[0054] This example illustrates the performance of the catalyst provided by the present application in hydrofining

[0055] The catalyst was loaded into a laboratory fixed bed reactor for reaction, and the raw material was mixed diesel oil. The catalyst was sulfided by in-situ sulfidation.

[0056] The catalyst sulfidation conditions were as follows: 2 wt% CS2 in aviation kerosene as sulfidation oil, volume space velocity 1.2 h -1 , hydrogen / oil volume ratio 500, and pressure 5.0 MPa. The sulfidation temperature was 340°C, and the sulfidation time was 7 h.

[0057] The reaction conditions were as follows: operating pressure 6.5 MPa, reaction temperature 365°C, hydrogen / oil volume ratio 500, and volume space velocity 1.0 h -1 . The results of the evaluation of the properties of the raw material and the product are shown in Table 2.

[0058] Table 2

[0059]

Claims

1. A method for preparing a hydrorefining catalyst, comprising the following steps: (1) Dissolve the zircon source and organic ligand in a solvent, add boehmite, mix, and then perform solvent heat treatment. The solvent heat treatment temperature is 80~150℃, and the heat treatment time is 8~72h. After the reaction, the product is centrifuged, washed, and dried to obtain Zr-MOF@Al2O3 precursor. The organic ligand is selected from one or more of benzoic acid, terephthalic acid, trimesic acid, pyromellitic acid, 2-amino-terephthalic acid, succinic acid, fumaric acid, and 2,5-thiophene dicarboxylic acid. The molar ratio of zircon to organic ligand is 0.01~5:

1. The amount of boehmite added is 0.002~0.1:1 of the molar ratio of zircon to aluminum. (2) The Zr-MOF@Al2O3 precursor was calcined to obtain zirconium-doped large-pore alumina support ZrO2@Al2O3; (3) At least one metal from Group VIII and at least one metal from Group VIB are loaded onto a ZrO2@Al2O3 support by impregnation. The amount of Group VIII metal fed is 2-20 wt% of the metal in the oxidation state, and the amount of Group VIB metal fed is 8-45 wt% of the metal in the oxidation state. The weight content of the zirconium-doped alumina support ZrO2@Al2O3 in the catalyst is 35-90 wt%. After drying and calcination, the hydrogenation refining catalyst is obtained.

2. The preparation method according to claim 1, characterized in that, The zirconium source mentioned in step (1) is selected from one or more of zirconium oxychloride, zirconium chloride, zirconium nitrate and zirconium sulfate.

3. The preparation method according to claim 1, characterized in that, The solvent is selected from one or more of deionized water, formic acid, acetic acid, and N,N-dimethylformamide.

4. The preparation method according to claim 1, characterized in that, The roasting temperature in step (2) is 400~800℃ and the roasting time is 1~10h.

5. The hydrorefining catalyst prepared by any one of claims 1-4.

6. A method for hydrotreating oil to remove polycyclic aromatic hydrocarbons, characterized in that, The hydrorefining catalyst described in claim 5 is reacted with the oil.

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