A hydrofining catalyst, its preparation method and use

Abstract

The application provides a hydrogenation pre-refining catalyst, and a preparation process thereof comprises the following steps: reacting a mixed solution of a salt of a metal promoter M and an organic ligand to obtain M-MOF, mixing the M-MOF with pseudo-boehmite and water to form a carrier, loading a Group VIII metal salt on the carrier by an impregnation method, and drying and calcining to obtain the catalyst. The catalyst comprises an alumina carrier modified by a surface promoter M and a Group VIII metal active component loaded on the carrier. The promoter on the surface of the carrier can effectively adjust the acidity of the surface of the carrier, improve the anti-arsenic and anti-sulfur performance of the carrier, inhibit olefin polymerization, delay coking, and the like. In addition, the alumina carrier is modified by using MOF. The MOF organic framework can effectively enrich the pore structure of the carrier, increase the specific surface area of the carrier, improve the anti-coking ability of the carrier, promote the diffusion and adsorption of reactants, promote the reaction, and improve the hydrogenation reaction efficiency.

Description

Technical Field

[0001] This invention relates to the field of hydrogenation catalyst technology, and in particular to a hydrogenation pre-purification catalyst. Background Technology

[0002] Currently, many countries use ethylene production as an indicator of their petrochemical development level. With my country's rapid economic development, ethylene production has increased year by year, reaching 14.19 million tons in 2010, a year-on-year increase of 32.3%. The quantity of its byproducts, cracked gasoline and catalytic gasoline, is also constantly increasing. How to effectively utilize these byproducts will have a significant impact on improving the economic efficiency of enterprises. Cracked gasoline or catalytic gasoline also contains a large amount of dienes, alkenyl aromatics, indene, and other unsaturated hydrocarbons, as well as impurities such as sulfur, nitrogen, and oxygen, leading to unstable gasoline properties. Dienes can react with other hydrocarbons in catalytic cracked gasoline to form coke, and the resulting coke easily accumulates in the catalyst bed, causing an increase in reaction pressure drop and eventually shutting down the unit. Therefore, selective hydrogenation is needed to remove it. Industrially, a two-stage hydrogenation process is generally used for refining. The first stage involves low-temperature liquid-phase hydrogenation to saturate chain conjugated olefins, cyclic conjugated olefins, and styrene, among others. The second stage involves high-temperature gas-phase hydrogenation to remove organic impurities containing sulfur, nitrogen, and oxygen, and to saturate monoolefins, which are then used as feedstock for aromatics extraction to produce benzene, toluene, and xylene. Due to the deterioration in the performance of the cracking feedstock, the diene content in cracked gasoline and catalytic gasoline increases, and they also contain impurities such as arsenic and gum. This places higher demands on current hydrogenation catalysts for cracked gasoline and catalytic gasoline.

[0003] CN1676580A discloses a selective hydrogenation method for removing dienes. This method involves contacting a distillate oil with a catalyst under hydrorefining conditions. The catalyst contains an alumina support and cobalt and / or nickel, molybdenum and / or tungsten, and alkali metal components supported on that support. The method is characterized by an atomic ratio of the alkali metal to cobalt or nickel of 1.3–6, a diene value of 1.8–1.9 g / 100g for the feed oil, and a diene value of 0.5–1.0 g / 100g for the finished oil. CN102451715A discloses a selective diene removal catalyst and its preparation method. The catalyst uses a titanium-aluminum composite oxide as a support, palladium as the active metal component, and Mo and / or Co as an additive. The catalyst has a large pore volume and specific surface area, and good high-temperature stability. CN101433841A discloses a selective hydrogenation catalyst using alumina as a support, with an active component Pd content of 0.2-0.5% and a catalyst with a specific surface area of ​​70-150 m² / g and cerium as an auxiliary agent. This catalyst has a narrow range of feedstock applications, a small specific surface area and pore volume, which affects its activity and selectivity, and also results in poor stability. CN109468142A discloses a distillate oil dediolefin catalyst and its preparation method. The catalyst is a Ni, Mo, Sr supported on a silica-alumina substrate. This catalyst exhibits high hydrogenation activity, good selectivity, and good water resistance. However, the addition of silicon enhances the acidity of the support, making the dienes more prone to polymerization, thus affecting the catalyst's lifespan. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a hydrotreating pre-refining catalyst. This catalyst has a simple preparation process, abundant catalyst pore distribution, large specific surface area, and good selectivity for diolefin removal. It can effectively remove diolefins from oil products, extend catalyst life, and extend the operating cycle of the unit.

[0005] To achieve the above-mentioned technical objectives, the technical solution of the present invention is as follows:

[0006] The first aspect of this invention aims to provide a method for preparing a hydrogenation pre-purification catalyst, comprising the following steps:

[0007] (1) The salt of the metal additive M is dissolved in a solvent to obtain a metal salt solution. The organic ligand is dissolved in the solvent and then mixed with the metal salt solution to react. After filtration and drying, powdered M-MOF is obtained. The metal additive M is selected from one or more of Zn, Mg, K, Na and Li, preferably Zn and / or Mg.

[0008] (2) The M-MOF, pseudoboehmite and water from step (1) are mixed evenly to obtain a slurry, which is then extruded, dried and calcined to obtain a carrier.

[0009] (3) The carrier obtained in (2) is impregnated with an impregnation solution prepared with a group VIII metal salt, and then dried and calcined to obtain the hydrogenation pre-purified catalyst.

[0010] Furthermore, the salt of the metal auxiliary M in step (1) is selected from one or more of nitrates, sulfates and acetates, preferably nitrates; the solvent is selected from one or more of water, methanol, ethanol, isopropanol and N,N-dimethylformamide, preferably water or N,N-dimethylformamide.

[0011] Furthermore, the organic ligand in step (1) is selected from one or more of 2-methylimidazole, terephthalic acid, terephthalamide and 2,5-dihydroxyterephthalic acid, preferably at least one of 2-methylimidazole and terephthalic acid.

[0012] Furthermore, in step (1), the metal salt and organic ligand are fed in a molar ratio of 0.05 to 0.5:1, preferably 0.1 to 0.16:1.

[0013] Furthermore, the temperature of the mixing reaction in step (1) is 10-150℃, preferably 20-120℃; the reaction time is 0.5-60h, preferably 5-48h; the drying temperature is 50-200℃, preferably 80-150℃; the drying time is 1-20h, preferably 8-12h; and the drying method is oven drying or vacuum drying, preferably vacuum drying.

[0014] Furthermore, in step (2), the amount of M-MOF added is such that the molar ratio of metal M to Al is 0.003 to 0.07:1, preferably 0.009 to 0.04:1.

[0015] Furthermore, in step (2), the amount of water added is 60-300% of the dry alumina basis, preferably 75-230%.

[0016] Furthermore, the pseudoboehmite mentioned in step (2) is at least one of macroporous pseudoboehmite and macroporous aluminosilicate.

[0017] Furthermore, the slurry in step (2) also includes some necessary adhesives, extrusion aids, etc. Specifically, it includes guar gum powder and nitric acid. The amount of guar gum powder added is 3 to 10% of the dry alumina basis, preferably 5 to 9%; the amount of nitric acid added is 0.2 to 12% of the dry alumina basis, preferably 0.5 to 6.3%.

[0018] Furthermore, the drying temperature in step (2) is 50-200℃, preferably 80-130℃; the calcination temperature is 350-1000℃, preferably 450-800℃.

[0019] Furthermore, the Group VIII metal mentioned in step (3) is selected from at least one of Ni, Pt and Pd, preferably Ni and / or Pd; the amount of Group VIII metal salt added, based on the total mass of the catalyst, makes the mass content of nickel oxide in the catalyst 5-30%, preferably 12-26%; and the mass content of palladium oxide 0.01-0.5%, preferably 0.1-0.4%.

[0020] Furthermore, the drying temperature in step (3) is 50-200℃, preferably 80-150℃; the drying time is 1-20h, preferably 3-8h; and the calcination temperature is 300-700℃, preferably 330-500℃.

[0021] The technical objective of the second aspect of this invention is to provide a hydrogenation pre-purification catalyst prepared by the above method.

[0022] The technical objective of the third aspect of this invention is to provide a method for the hydrodeolefination of distillate oil, wherein the distillate oil is reacted with the hydropre-refining catalyst.

[0023] Furthermore, the distillate oil is at least one of the following: cracked gasoline middle fractions C6-C8, C5-C9, cracked gasoline full fraction, coking gasoline, and catalytic gasoline, preferably at least one of the following: cracked gasoline middle fractions C6-C8, C5-C9, and cracked gasoline full fraction.

[0024] Furthermore, the reaction process conditions are as follows: inlet temperature 50–95℃, reaction pressure 1.0–4.0 MPa, hydrogen-to-oil ratio 40–160, and liquid hourly space velocity 2.5–6 h⁻¹. -1 .

[0025] The technical solution of the present invention has the following technical effects:

[0026] The hydrogenation pre-purification catalyst of this invention comprises an alumina support modified with surface additive M and a Group VIII metal active component supported on the support. The additive on the support surface can effectively adjust the acidity of the support surface, improve its resistance to arsenic and sulfur, and simultaneously inhibit olefin polymerization and delay coking. Furthermore, the alumina support is modified with MOF (Metal-Oxide-Foil). The MOF organic framework calcination process effectively enriches the pore structure of the support, increases its specific surface area, improves its anti-coking ability, promotes the diffusion and adsorption of reactants, accelerates the reaction, and improves the hydrogenation reaction efficiency. Detailed Implementation

[0027] The present invention will be described in detail below through embodiments, but the present invention is not limited to these embodiments.

[0028] Example 1

[0029] (1) Dissolve 6 mol of zinc nitrate and 24 mol of 2-methylimidazole in 30 mL of methanol solution respectively, then mix the solutions and stir at room temperature for 2 h. Wash the precipitate repeatedly with methanol several times, and then dry it at 60 °C for 4 h to obtain ZIF-8.

[0030] (2) Mix 60.2g of macroporous boehmite (83% dry basis), 4.8g of ZIF-8 (Zn / Al molar ratio of 0.02:1) prepared in step (1), 4g of guar gum powder, 1.4g of nitric acid (concentration of 67%), and 78g of water, and press for 30 minutes to form a slurry. Extrude the slurry into shape using a cylindrical perforated plate with a diameter of 2.0mm on an extruder. Dry the formed cylindrical strips at 100℃ for 6 hours, and then calcine them at 750℃ for 2 hours to obtain an alumina carrier.

[0031] (3) Dissolve 44.05g of nickel nitrate in water to make an impregnation solution, and impregnate the carrier prepared in step (2) by equal volume impregnation method. Dry at 110℃ for 6 hours, and then calcine at 340℃ for 3 hours to obtain catalyst A1. In catalyst A1, the active component nickel oxide accounts for 17.96% by weight.

[0032] Example 2

[0033] (1) Dissolve 6 mol of zinc nitrate and 24 mol of 2-methylimidazole in 30 mL of methanol solution respectively, then mix the solutions and stir at room temperature for 2 h. Wash the precipitate repeatedly with methanol several times, and then dry it at 60 °C for 4 h to obtain ZIF-8.

[0034] (2) Mix 60.2g of macroporous boehmite (83% dry basis), 18.5g of ZIF-8 (Zn / Al molar ratio of 0.08:1) prepared in step (1), 4g of guar gum powder, 1.4g of nitric acid (concentration of 67%), and 78g of water, and press for 30 minutes to form a slurry. Extrude the slurry into shape using a cylindrical perforated plate with a diameter of 2.0mm on an extruder. Dry the formed cylindrical strips at 100℃ for 6 hours, and then calcine them at 750℃ for 2 hours to obtain an alumina carrier.

[0035] (3) Dissolve 46.5g of nickel nitrate in water to prepare an impregnation solution, and impregnate it on the above carrier by equal volume impregnation method. Dry at 110℃ for 6 hours, and then calcine at 340℃ for 3 hours to obtain catalyst A2. The nickel oxide content in catalyst A2 is 17.44%.

[0036] Example 3

[0037] (1) Dissolve 6 mol of zinc nitrate and 24 mol of 2-methylimidazole in 30 mL of methanol solution respectively, then mix the solutions and stir at room temperature for 2 h. Wash the precipitate repeatedly with methanol several times, and then dry it at 60 °C for 4 h to obtain ZIF-8.

[0038] (2) Mix 60.2g of macroporous boehmite (83% dry basis), 1.2g of ZIF-8 (Zn / Al molar ratio of 0.005:1) prepared in step (1), 4g of guar gum powder, 1.4g of nitric acid (concentration of 67%), and 80g of water, and press for 30 minutes to form a slurry. Extrude the slurry into shape using a cylindrical perforated plate with a diameter of 2.0mm on an extruder. Dry the formed cylindrical strip at 120℃ for 3 hours, and then calcine at 720℃ for 2 hours to obtain an alumina carrier.

[0039] (3) Dissolve 58.7g of nickel nitrate in water to prepare an impregnation solution, impregnate it on the above-mentioned carrier by equal volume impregnation method, dry it at 120℃ for 3 hours, and then calcine it at 340℃ for 3 hours to obtain catalyst A3. The nickel oxide content in catalyst A3 is 23.03%.

[0040] Example 4

[0041] (1) Dissolve 6 mol of zinc nitrate and 24 mol of 2-methylimidazole in 30 mL of methanol solution respectively, then mix the solutions and stir at room temperature for 2 h. Wash the precipitate repeatedly with methanol several times, and then dry it at 60 °C for 4 h to obtain ZIF-8.

[0042] (2) Mix 60.2g of macroporous boehmite (83% dry basis), 4.8g of ZIF-8 (Zn / Al molar ratio of 0.02:1) prepared in step (1), 4g of guar gum powder, 1.4g of nitric acid (concentration of 67%), and 84g of water, and press for 30 minutes to form a slurry. Extrude the slurry into shape using a cylindrical perforated plate with a diameter of 1.5mm on an extruder. Dry the formed cylindrical strip at 110℃ for 6 hours, and then calcine at 700℃ for 2 hours to obtain an alumina carrier.

[0043] (3) Dissolve 100g of nickel nitrate in water to prepare an impregnation solution, impregnate it on the above-mentioned carrier by vacuum rotary evaporation impregnation method, dry it at 110℃ for 2 hours, and then calcine it at 320℃ for 3 hours to obtain catalyst A4, in which the nickel oxide content is 33.00%.

[0044] Example 5

[0045] (1) Dissolve 6 mol of zinc nitrate and 24 mol of 2-methylimidazole in 30 mL of methanol solution respectively, then mix the solutions and stir at room temperature for 2 h. Wash the precipitate repeatedly with methanol several times, and then dry it at 60 °C for 4 h to obtain ZIF-8.

[0046] (2) Mix 60.2g of macroporous boehmite (83% dry basis), 4.8g of ZIF-8 (Zn / Al molar ratio of 0.02:1) prepared in step (1), 4g of guar gum powder, 1.4g of nitric acid (concentration of 67%), and 75g of water, and press for 30 minutes to form a slurry. Extrude the slurry into shape using a cylindrical perforated plate with a diameter of 1.5mm on an extruder. Dry the formed cylindrical strips at 110℃ for 6 hours, and then calcine them at 750℃ for 2 hours to obtain an alumina carrier.

[0047] (3) Dissolve 20g of nickel nitrate in water to prepare an impregnation solution, impregnate it on the above-mentioned carrier by vacuum rotary evaporation impregnation method, dry it at 110℃ for 3 hours, and then calcine it at 330℃ for 3 hours to obtain catalyst A5, in which the nickel oxide content is 9%.

[0048] Comparative Example 1

[0049] 60.2g of macroporous pseudoboehmite (83% dry basis), 4g of guar gum powder, 1.4g of nitric acid (67% concentration), and 78g of water were mixed and crushed for 30 minutes to form a slurry. The slurry was then extruded into cylindrical strips using a 2.0mm cylindrical perforated plate on an extruder. The cylindrical strips were dried at 100℃ for 6 hours and then calcined at 750℃ for 2 hours to form an alumina carrier.

[0050] 42.7g of nickel nitrate was dissolved in water to prepare an impregnation solution, which was then impregnated onto the above-mentioned support using an equal-volume impregnation method. The solution was dried at 110℃ for 6 hours and then calcined at 340℃ for 3 hours to obtain catalyst C1, which has a nickel oxide content of 18%.

[0051] Comparative Example 2

[0052] 60.2g of macroporous boehmite (83% dry basis), 4g of guar gum powder, 1.4g of nitric acid (67% concentration), 78g of water, and 6.2g of zinc nitrate (Zn / Al molar ratio of 0.02:1) were mixed and crushed for 30 minutes to form a slurry. The slurry was then extruded into cylindrical strips using a 2.0mm cylindrical perforated plate on an extruder. The formed cylindrical strips were dried at 100℃ for 6 hours and then calcined at 750℃ for 2 hours to form an alumina carrier.

[0053] 44.05g of nickel nitrate was dissolved in water to prepare an impregnation solution, which was then impregnated onto the above-mentioned support using an equal-volume impregnation method. The solution was dried at 110℃ for 6 hours and then calcined at 340℃ for 3 hours to obtain catalyst C2, which contained 17.97% nickel oxide.

[0054] The physicochemical properties of the catalysts prepared in the above examples and comparative examples are shown in Table 1.

[0055] Table 1

[0056] A1 250.3 15.8 17.96 2.70 A2 279.7 20.7 17.44 9.58 A3 223.8 13.9 23.03 0.65 A4 238.2 15.1 33.00 2.20 A5 261.6 16.4 9.00 3.00 C1 204.3 13.3 18.00 0 C2 191.6 12.9 17.97 2.69

[0057] Example 6

[0058] The catalyst was loaded onto an adiabatic bed for activation reaction. The feedstock was the C6-C8 middle fraction of cracked gasoline, with a diene value of 30.12 g iodine / 100 g oil and a gum content of 47 mg / 100 g oil. The diene value in the oil was determined by the malic anhydride method and expressed as g iodine / 100 g oil.

[0059] Catalyst activation conditions: activation pressure is 3.0 MPa, activation temperature is 400℃, reduction is carried out under hydrogen conditions for 5 hours, and after cooling to 45℃, straight-run gasoline containing 1% CS2 is used for passivation for 3 hours. After passivation, the feedstock is switched.

[0060] Reaction conditions: operating pressure 3.0 MPa, inlet temperature 65℃, hydrogen-to-oil ratio 50, fresh oil volume hourly space velocity 3.0 h⁻¹. -1 The evaluation results are shown in Table 2.

[0061] Table 2 shows the hydrogenation performance of the catalysts obtained in the examples and comparative examples.

[0062]

Claims

1. A method for preparing a hydrotreating pre-purification catalyst for the hydrode-diolefination of distillate oil, comprising the following steps: (1) Dissolve the salt of metal auxiliary M in a solvent to obtain a metal salt solution, dissolve the organic ligand 2-methylimidazole in a solvent and mix it with the metal salt solution to react, filter and dry to obtain powdered M-MOF, wherein the metal auxiliary M is Zn; (2) Mix M-MOF, pseudoboehmite and water from step (1) to obtain a slurry. After extrusion molding, drying and calcination, a carrier is obtained. The amount of M-MOF added is 0.003~0.07:1 in the molar ratio of metal M to Al. (3) The carrier obtained in (2) is impregnated with an impregnation solution prepared with a group VIII metal salt, and then dried and calcined to obtain the hydrogenation pre-purified catalyst. The group VIII metal is Ni, and the amount of group VIII metal salt added is such that the mass content of nickel oxide in the catalyst is 5~30%.

2. The preparation method according to claim 1, characterized in that, The salt of the metal additive M is selected from one or more of nitrates, sulfates, and acetates.

3. The preparation method according to claim 1, characterized in that, The solvent is selected from one or more of water, methanol, ethanol, isopropanol and N,N-dimethylformamide.

4. The preparation method according to claim 1, characterized in that, In step (1), the metal salt and organic ligand are fed in a molar ratio of 0.05 to 0.5:

1.

5. The preparation method according to claim 1, characterized in that... The temperature of the mixed reaction in step (1) is 10~150℃ and the reaction time is 0.5~60h.

6. The hydrogenation pre-purification catalyst prepared by the preparation method according to any one of claims 1-5.

7. A method for hydrotreating distillate oil to remove dienes, wherein the distillate oil is reacted with the hydrotreating pre-refining catalyst of claim 6.

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