A method for presulfiding treatment of a hydrogenation catalyst

Abstract

This application discloses a pre-sulfurization treatment method for a hydrogenation catalyst, relating to the field of catalyst pre-sulfurization technology. The method involves adding a hydrogenation catalyst, a sulfiding agent (a), a dispersant, and a modified composite wetting agent to a sulfidation furnace for pre-wetting under a nitrogen atmosphere; then, hydrogen is introduced to replace the nitrogen, sulfiding agent (b) is added, and the temperature is raised for deep sulfidation; after sulfidation, nitrogen is introduced to replace the hydrogen, followed by segmented passivation, and the catalyst is cooled and discharged to obtain the pre-sulfurized hydrogenation catalyst. The modified composite wetting agent is composed of isocyanate silane-grafted modified polyethylene glycol monomethyl ether and hydroxyl-branched star-shaped polyether, which can improve the wetting effect of the sulfiding agent, thereby improving the sulfidation effect. The segmented passivation process enhances the passivation performance of the catalyst, avoiding the oxidation and heat generation problems that are common in catalysts. This method solves the problems of poor sulfidation uniformity, easy catalyst damage, and spontaneous combustion in existing technologies, improving the sulfidation rate and stability of the catalyst, and enabling safe long-term storage of the pre-sulfurized catalyst.

Description

Technical Field

[0001] This invention relates to the field of catalyst presulfurization technology, and specifically to a method for presulfurization treatment of a hydrogenation catalyst. Background Technology

[0002] Hydrogenation catalysts are core materials used in petroleum refining, coal chemical industry, and other fields to achieve reactions such as hydrorefining and hydrocracking. Their activity mainly depends on the degree of sulfidation and dispersion uniformity of the active metal components (such as Mo, Co, Ni, etc.). Sulfidation treatment, as a key pretreatment process before the start-up of the hydrogenation catalyst unit, aims to convert the metal oxides in the catalyst into highly active metal sulfide phases. Simultaneously, it is crucial to ensure a mild and controllable sulfidation process to avoid catalyst structural damage, active site poisoning, and safety hazards. Therefore, the rationality of the presulfidation process directly determines the catalyst's catalytic performance, service life, and safety in industrial applications. However, existing technologies for presulfidating hydrogenation catalysts suffer from problems such as poor sulfidation uniformity, excessively rapid sulfur source release leading to hot spots and structural damage, poor passivation after sulfidation, and catalyst susceptibility to overheating and spontaneous combustion. Therefore, solving these problems has become a research hotspot in the field of catalyst presulfidation. Chinese invention patent application CN111068794A discloses an external pre-sulfurization method for hydrogenation catalysts. The method involves first uniformly mixing a sulfiding agent and an oxidized catalyst, followed by heat treatment; then, hydrogen gas is introduced for a period of time; finally, hydrocarbon oil is loaded onto the treated intermediate material to obtain a deeply sulfidated pre-sulfurized catalyst. The pre-sulfurized hydrogenation catalyst prepared by this method can be directly adjusted to operating conditions and introduced with feedstock for start-up, without the need for catalyst activation. This achieves complete catalyst passivation without requiring a passivation step. While this method avoids the catalyst passivation step to some extent, it is not suitable for long-term storage of pre-sulfurized catalysts, which still require passivation treatment for long-term storage.

[0003] Therefore, how to study a pre-sulfurization treatment method for hydrogenation catalysts that has a deep pre-sulfurization effect, improves catalyst performance, and has a good passivation effect, and allows for safe long-term storage of pre-sulfurized catalysts, has become an urgent problem to be solved. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application provides a pre-sulfurization treatment method for hydrogenation catalysts. The method involves first adding the hydrogenation catalyst, dispersant, modified compound wetting agent, and sulfiding agent a to a sulfidation furnace for impregnation and preliminary sulfidation, then adding sulfiding agent b for deep sulfidation. After sulfidation, the pre-sulfurized hydrogenation catalyst is passivated through a segmented passivation process to obtain the pre-sulfurized hydrogenation catalyst.

[0005] To achieve the above objectives, this application provides the following technical solution: This application provides a method for presulfurization treatment of a hydrogenation catalyst, comprising the following steps: Under a nitrogen atmosphere, hydrogenation catalyst, sulfiding agent a, dispersant and modified compound wetting agent are added to the sulfidation furnace, the sulfidation furnace is rotated, the mixture is pre-wetted; Stop the nitrogen supply, introduce hydrogen into the furnace to replace the nitrogen, and circulate the hydrogen. Add the vulcanizing agent b into the furnace and heat up the vulcanizing process. After sulfidation, the temperature is lowered, and nitrogen is introduced into the furnace to replace the hydrogen for staged passivation. After passivation, the furnace is cooled to room temperature, and the hydrogenation catalyst is removed to obtain the pre-sulfided hydrogenation catalyst. The modified compound wetting agent is obtained by compounding an isocyanate silane grafted modified wetting agent with a hydroxyl multibranched star-shaped polyether; The wetting agent is polyethylene glycol monomethyl ether; The hydroxyl-branched star-shaped polyether is obtained by ring-opening polymerization of pentaerythritol with ethylene oxide and propylene oxide.

[0006] Hydrogenation catalysts generally consist of an active metal component and a support. Before pre-sulfurization, the active metal exists in an oxidized state; after pre-sulfurization, it is converted into a metal sulfide. The active metal oxide component typically accounts for 10-40% of the hydrogenation catalyst, while the support accounts for 60-90%. The active component of the hydrogenation catalyst includes any one or more of molybdenum-based oxides, tungsten-based oxides, nickel-based oxides, and cobalt-based oxides; the support for the hydrogenation catalyst includes any one of alumina, silica, and titanium dioxide, and the specific surface area of ​​the hydrogenation catalyst is ≥180 m². 2 / g.

[0007] Preferably, the vulcanizing agent a includes any one of ammonium trisulfide, ammonium tetrasulfide, tert-butylamine trisulfide, tert-butylamine tetrasulfide, and dimethyl disulfide; and the vulcanizing agent b is elemental sulfur.

[0008] In the initial pre-sulfurization process of the hydrogenation catalyst, this scheme uses sulfiding agent a, which has the characteristic of mild decomposition at 140-160℃. It can slowly release active sulfur, which undergoes a mild sulfidation reaction with the active metal oxides on the catalyst surface and in the pores to obtain metal sulfide precursors. In the deep sulfidation process, elemental sulfur is used as the sulfiding agent, which can rapidly decompose at high temperatures to produce a large amount of highly active sulfur. This sulfur then undergoes a deep reaction with the metal sulfide precursors generated in the initial sulfidation, transforming them into highly active and stable metal sulfide phases. At the same time, the gradual release rate of active sulfur prevents excessively violent local reactions and avoids damage to active sites. High-temperature deep sulfidation achieves deep conversion of active components and improves the sulfidation rate.

[0009] Preferably, the dispersant comprises any one of dodecylbenzene, tetradecylbenzene, alkylnaphthalene, and methylnaphthalene.

[0010] Preferably, the rotation speed of the rotary vulcanizing furnace is 2-10 rpm; the specific steps of the pre-impregnation are as follows: after the vulcanizing furnace is rotated and stirred for 30-40 min, the temperature is raised to 140-160℃ at a rate of 1-1.5℃ / min, and the temperature is maintained for 1.5-2 h to complete the pre-impregnation.

[0011] Preferably, the specific preparation steps of the modified compound wetting agent are as follows: Polyethylene glycol monomethyl ether with a molecular weight of 350-450 and anhydrous toluene were added to a reaction vessel, stirred, and heated to 55-65°C. The mixture was then dehydrated under vacuum to obtain a transparent solution. The temperature was lowered to 40-45°C, and dibutyltin dilaurate and 2,6-di-tert-butyl-p-cresol were added. The mixture was stirred for 10-15 minutes, and γ-isocyanate propyltriethoxysilane was added dropwise at a rate of 1 drop / s. The temperature was then raised to 60-65°C, and the reaction was carried out at a constant temperature for 3-4 hours. After the reaction was completed, the mixture was distilled under reduced pressure to obtain the isocyanate silane grafted modified wetting agent. Pentaerythritol and potassium hydroxide were added to a reactor. Under nitrogen atmosphere, the mixture was stirred and heated to 120-130℃, and kept at this temperature for dehydration for 0.8-1.2 hours. The temperature was then lowered to 80-90℃, and ethylene oxide was introduced. The reaction pressure was controlled at 0.2-0.3 MPa, and the temperature at 100-110℃. The reaction was kept at this temperature for 3-4 hours. Then, propylene oxide was introduced. The reaction pressure was controlled at 0.2-0.3 MPa, and the temperature at 110-120℃. The reaction was kept at this temperature for 2-3 hours. The temperature was then lowered to below 60℃, and glacial acetic acid was added to adjust the pH of the system to 6.5-7.5. The mixture was stirred for 30-40 minutes and then distilled under reduced pressure to obtain hydroxyl-branched star-shaped polyether. The isocyanate silane grafted modified wetting agent and hydroxyl multibranched star-shaped polyether were compounded at a mass ratio of 1:(1.5-2.5) and stirred evenly to obtain the modified compound wetting agent.

[0012] Isocyanate silanes are grafted onto polyethylene glycol monomethyl ether via the addition reaction of isocyanate groups and primary hydroxyl groups. The siloxane groups on the grafted polyethylene glycol monomethyl ether wetting agent can covalently bond with the hydroxyl groups on the catalyst support surface, anchoring the wetting agent to the catalyst support surface and preventing wetting agent loss due to factors such as high temperature or hydrogen circulation. This provides a stable guiding layer for vulcanizing agent wetting. Furthermore, by compounding with hydroxylated multibranched star-shaped polyethers, the multihydroxyl structure forms hydrogen bonds with the vulcanizing agent and dispersant, reducing the surface tension of the vulcanizing agent. Relying on the guiding layer formed by the anchored wetting agent, the vulcanizing agent is promoted to spread uniformly along the pore walls, preventing agglomeration on the catalyst surface and guiding the vulcanizing agent to penetrate directionally into the micropores inside the catalyst, ensuring sufficient contact with the metal active components within the pores, thereby improving the wetting effect and uniformity of the vulcanizing agent.

[0013] Preferably, the mass ratio of polyethylene glycol monomethyl ether, anhydrous toluene, dibutyltin dilaurate, 2,6-di-tert-butyl-p-cresol, and γ-isocyanate propyltriethoxysilane is 100:(50-60):(0.05-0.1):(0.01-0.02):(10-12); and the mass ratio of pentaerythritol, potassium hydroxide, ethylene oxide, and propylene oxide is 10:(0.2-0.3):(40-50):(20-30).

[0014] Preferably, the hydrogen circulation pressure is 0.3-0.4 MPa and the flow rate is 8-10 m³ / s. 3 / h; the vulcanizing agent b is added to the reactor in three batches, with a 30-minute interval between each batch; the specific process of the heating and vulcanization is as follows: the temperature is increased to 300-375℃ at a rate of 1-1.5℃ / min, and the temperature is maintained for 5-6 hours.

[0015] The purpose of adding the vulcanizing agent b into the vulcanizing furnace in three stages is to prevent sulfur deposition caused by excessively high local sulfur vapor pressure and to avoid clogging of the catalyst channels.

[0016] Preferably, the specific process of lowering the temperature is as follows: cooling to 180-220℃ at a rate of 1-1.5℃ / min.

[0017] Preferably, the specific process of segmented passivation is as follows: after nitrogen gas is introduced to replace hydrogen gas, a mixture of nitrogen and oxygen gas is introduced, with an oxygen volume fraction of 0.2-0.5% and a flow rate of 4-5 m³ / h. 3 The first stage of passivation lasts 1.2-1.5 hours; the temperature is then lowered to 120-150°C at a rate of 0.8-1°C / min, and a mixture of nitrogen and oxygen is introduced, with an oxygen volume fraction of 1-2% and a flow rate of 4-5 m³ / min. 3 The dibutyl phthalate is atomized and sprayed into the vulcanizing furnace at a spray rate of 0.5-1 kg / h. The second passivation stage lasts 1.5-2 hours. The temperature is then further reduced to 60-80℃ at a rate of 0.8-1℃ / min, and a mixture of nitrogen and oxygen is introduced, with an oxygen volume fraction of 3-5% and a flow rate of 4-5 m³ / min. 3 / h, the third stage passivation lasts 1.2-1.5h.

[0018] After high-temperature sulfidation, the catalyst surface has high activity and is prone to violent reaction with the passivating agent. Therefore, a small amount of oxygen is first introduced to form an extremely thin oxide protective layer on the catalyst surface, blocking the direct exposure of active sites. Then, the second stage of deep passivation is carried out by increasing the oxygen volume fraction and spraying liquid-phase passivating agent to form a uniform and stable passivation film on the catalyst surface and pores. Finally, in the third stage, the catalyst activity has been significantly reduced, and the oxygen volume fraction can be increased to ensure the complete formation of the passivation film, forming a structurally stable, oxidation-resistant, and non-self-ignition-resistant passivation film layer.

[0019] Preferably, the mass ratio of the hydrogenation catalyst, sulfiding agent a, dispersant, modified compound wetting agent, sulfiding agent b, and dibutyl phthalate is 100:(8-10):(3-5):(0.15-0.35):(4-6):(1-2).

[0020] The beneficial effects of this application are: This application obtains a modified wetting agent by grafting isocyanate silane onto polyethylene glycol monomethyl ether molecules. The siloxane groups on the molecular chain are covalently bonded to the hydroxyl groups on the catalyst support, anchoring the wetting agent to the catalyst surface and guiding the vulcanizing agent to directionally wet the catalyst surface. At the same time, the hydroxylated multibranched star-shaped polyether has the characteristics of low viscosity and multiple hydroxyl groups, without steric hindrance interference, and can quickly penetrate into the catalyst micropores. Furthermore, its hydroxyl structure can form hydrogen bonds with the vulcanizing agent, reducing its surface tension and allowing the vulcanizing agent to spread along the micropore walls and fully contact the metal active components in the pores, thereby improving the vulcanization rate of the catalyst.

[0021] The staged passivation process employed in this application enables safe and efficient passivation of the catalyst. Pre-passivation is first performed at a low oxygen concentration to form an extremely thin and dense initial oxide protective film on the catalyst surface, preventing direct exposure of active sites, suppressing the intense exothermic reaction in subsequent oxidation processes, and avoiding the formation of localized hot spots. Then, the oxygen concentration is gradually increased, and a liquid-phase passivating agent is added to form a composite passivation film on the catalyst surface, stabilizing the catalyst structure and improving passivation uniformity.

[0022] The hydrogenation catalyst pre-sulfurization treatment method provided in this application can effectively improve the sulfidation rate of the catalyst and enhance the stability of the catalyst after passivation, thus solving the problems of poor catalyst pre-sulfurization effect, poor passivation film structure stability, and easy spontaneous combustion in the prior art. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A process flow diagram of a presulfurization treatment method for a hydrogenation catalyst provided in this application. Detailed Implementation

[0025] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0026] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0027] The following specific embodiments further illustrate this point: Example 1 like Figure 1 As shown, a presulfurization treatment method for a hydrogenation catalyst includes the following steps: 1. Polyethylene glycol monomethyl ether with a molecular weight of 400 and anhydrous toluene were added to a reaction vessel, stirred, and heated to 60°C. The mixture was then dehydrated under vacuum to obtain a transparent solution. The temperature was lowered to 43°C, and dibutyltin dilaurate and 2,6-di-tert-butyl-p-cresol were added. The mixture was stirred for 12 min, and γ-isocyanate propyltriethoxysilane was added dropwise at a rate of 1 drop / s. The temperature was then raised to 63°C and the reaction was maintained at this temperature for 3.5 h. After the reaction was completed, the mixture was distilled under reduced pressure to obtain an isocyanate silane graft-modified wetting agent. The mass ratio of polyethylene glycol monomethyl ether, anhydrous toluene, dibutyltin dilaurate, 2,6-di-tert-butyl-p-cresol, and γ-isocyanate propyltriethoxysilane was 100:55:0.08:0.015:11.

[0028] 2. Pentaerythritol and potassium hydroxide were added to a reaction vessel. Under nitrogen atmosphere, the mixture was stirred and heated to 125°C, kept at this temperature for 1 hour to dehydrate, then cooled to 85°C. Ethylene oxide was introduced, and the reaction pressure was controlled at 0.25 MPa and the temperature at 105°C. The reaction was maintained at this temperature for 3.5 hours. Then propylene oxide was introduced, and the reaction pressure was controlled at 0.25 MPa and the temperature at 115°C. The reaction was maintained at this temperature for 2.5 hours. The temperature was then lowered to below 60°C, glacial acetic acid was added, and the pH of the system was adjusted to 7. The mixture was stirred for 35 minutes and then distilled under reduced pressure to obtain hydroxyl-branched star-shaped polyether. The mass ratio of pentaerythritol, potassium hydroxide, ethylene oxide, and propylene oxide was 10:0.25:45:25.

[0029] 3. The isocyanate silane grafted modified wetting agent and hydroxyl multibranched star-shaped polyether are compounded at a mass ratio of 1:2 and stirred evenly to obtain the modified compound wetting agent.

[0030] 4. Under a nitrogen atmosphere, for surfaces with a specific surface area ≥180m² 2 / g of NiO-WO3 / Al2O3, ammonium trisulfide, dodecylbenzene and modified compound wetting agent are added to the vulcanizing furnace. The vulcanizing furnace is rotated at a rate of 5 rpm and stirred for 35 min. The mixture is heated to 150℃ at a rate of 1.2℃ / min and held at that temperature for 1.7 h.

[0031] 5. Stop the nitrogen supply and introduce hydrogen into the furnace to replace the nitrogen, thus initiating hydrogen circulation at a pressure of 0.35 MPa and a flow rate of 9 m³ / h. 3 Elemental sulfur is added to the furnace in three portions, with a 30-minute interval between each addition. After the addition is complete, the temperature is raised to 350°C at a rate of 1.2°C / min and held for 5.5 hours.

[0032] 6. After vulcanization, the temperature is lowered to 200℃ at a rate of 1.2℃ / min. Nitrogen gas is introduced into the furnace to replace the hydrogen gas. After replacement, a mixture of nitrogen and oxygen gas is introduced, with an oxygen volume fraction of 0.3% and a flow rate of 4.5m³. 3 The temperature was then decreased to 130℃ at a rate of 0.9℃ / min, and a mixture of nitrogen and oxygen was introduced at a flow rate of 4.5 m³ / min, with an oxygen volume fraction of 1.5%. 3 The dibutyl phthalate was atomized and sprayed into the vulcanizing furnace at a spray rate of 0.5 kg / h for 1.8 h passivation. Then, the temperature was lowered to 70 °C at a rate of 0.9 °C / min, and a mixture of nitrogen and oxygen was introduced, with an oxygen volume fraction of 4% and a flow rate of 4.5 m³ / min. 3 / h, passivate for 1.3h, after passivation, cool to room temperature, remove the hydrogenation catalyst, and obtain the presulfurized hydrogenation catalyst prepared by the method described in Example 1.

[0033] The mass ratio of hydrogenation catalyst, ammonium trisulfide, dodecylbenzene, modified compound wetting agent, elemental sulfur, and dibutyl phthalate in steps 4-6 is 100:9:4:0.2:5:1.5.

[0034] Example 2 like Figure 1 As shown, a presulfurization treatment method for a hydrogenation catalyst includes the following steps: 1. Polyethylene glycol monomethyl ether with a molecular weight of 350 and anhydrous toluene were added to a reaction vessel, stirred, and heated to 55°C. The mixture was then dehydrated under vacuum to obtain a transparent solution. The temperature was lowered to 40°C, and dibutyltin dilaurate and 2,6-di-tert-butyl-p-cresol were added. The mixture was stirred for 15 min, and γ-isocyanate propyltriethoxysilane was added dropwise at a rate of 1 drop / s. The temperature was then raised to 60°C and the reaction was maintained at this temperature for 4 h. After the reaction was completed, the mixture was distilled under reduced pressure to obtain an isocyanate silane graft-modified wetting agent. The mass ratio of polyethylene glycol monomethyl ether, anhydrous toluene, dibutyltin dilaurate, 2,6-di-tert-butyl-p-cresol, and γ-isocyanate propyltriethoxysilane was 100:50:0.05:0.01:10.

[0035] 2. Pentaerythritol and potassium hydroxide were added to a reaction vessel. Under nitrogen atmosphere, the mixture was stirred and heated to 120°C, kept at this temperature for 1.2 hours to dehydrate. The temperature was then lowered to 80°C, and ethylene oxide was introduced. The reaction pressure was controlled at 0.2 MPa, and the temperature at 100°C. The reaction was maintained at this temperature for 4 hours. Then, propylene oxide was introduced. The reaction pressure was controlled at 0.2 MPa, and the temperature at 110°C. The reaction was maintained at this temperature for 3 hours. The temperature was then lowered to below 60°C, and glacial acetic acid was added to adjust the pH of the system to 6.5. The mixture was stirred for 40 minutes and then distilled under reduced pressure to obtain hydroxyl-branched star-shaped polyether. The mass ratio of pentaerythritol, potassium hydroxide, ethylene oxide, and propylene oxide was 10:0.2:40:20.

[0036] 3. The isocyanate silane grafted modified wetting agent and hydroxyl multibranched star-shaped polyether are compounded at a mass ratio of 1:1.5 and stirred evenly to obtain the modified compound wetting agent.

[0037] 4. Under a nitrogen atmosphere, for surfaces with a specific surface area ≥180m² 2 / g of CoO-MoO3 / Al2O3, ammonium tetrasulfide, tetradecylbenzene and modified compound wetting agent are added to the vulcanizing furnace. The vulcanizing furnace is rotated at a rate of 2 rpm and stirred for 30 min. The mixture is heated to 140℃ at a rate of 1℃ / min and held at that temperature for 1.5 h.

[0038] 5. Stop the nitrogen supply and introduce hydrogen into the furnace to replace the nitrogen, thus initiating hydrogen circulation at a pressure of 0.3 MPa and a flow rate of 8 m³ / s. 3 Elemental sulfur is added to the furnace in three portions, with a 30-minute interval between each addition. After the addition is complete, the temperature is increased to 300°C at a rate of 1°C / min and held for 6 hours.

[0039] 6. After vulcanization, cool the furnace to 180°C at a rate of 1°C / min, and introduce nitrogen gas to replace the hydrogen gas. After replacement, introduce a mixture of nitrogen and oxygen gas with an oxygen volume fraction of 0.2% at a flow rate of 4 m³ / min. 3 The temperature was then decreased to 120°C at a rate of 0.8°C / min, and a mixture of nitrogen and oxygen was introduced, with an oxygen volume fraction of 1% and a flow rate of 4 m³ / min. 3 The dibutyl phthalate was atomized and sprayed into the vulcanizing furnace at a spray rate of 1 kg / h for 2 hours for passivation. Then, the temperature was lowered to 60℃ at a rate of 0.8℃ / min, and a mixture of nitrogen and oxygen (oxygen volume fraction 3%) was introduced at a flow rate of 4 m³ / min. 3 / h, passivate for 1.5h, after passivation is completed, cool to room temperature, unload the hydrogenation catalyst, and obtain the presulfurized hydrogenation catalyst prepared by the method described in Example 1.

[0040] The mass ratio of hydrogenation catalyst, ammonium tetrasulfide, tetradecylbenzene, modified compound wetting agent, elemental sulfur, and dibutyl phthalate in steps 4-6 is 100:8:3:0.15:4:1.

[0041] Example 3 like Figure 1 As shown, a presulfurization treatment method for a hydrogenation catalyst includes the following steps: 1. Polyethylene glycol monomethyl ether with a molecular weight of 450 and anhydrous toluene were added to a reaction vessel, stirred, and heated to 65°C. The mixture was then dehydrated under vacuum to obtain a transparent solution. The temperature was lowered to 45°C, and dibutyltin dilaurate and 2,6-di-tert-butyl-p-cresol were added. The mixture was stirred for 10 min, and γ-isocyanate propyltriethoxysilane was added dropwise at a rate of 1 drop / s. The temperature was then raised to 65°C and the reaction was maintained at this temperature for 3 h. After the reaction was completed, the mixture was distilled under reduced pressure to obtain an isocyanate silane graft-modified wetting agent. The mass ratio of polyethylene glycol monomethyl ether, anhydrous toluene, dibutyltin dilaurate, 2,6-di-tert-butyl-p-cresol, and γ-isocyanate propyltriethoxysilane was 100:60:0.1:0.02:12.

[0042] 2. Pentaerythritol and potassium hydroxide were added to a reaction vessel. Under nitrogen atmosphere, the mixture was stirred and heated to 130°C, kept at this temperature for 0.8 h to dehydrate, then cooled to 90°C. Ethylene oxide was introduced, and the reaction pressure was controlled at 0.3 MPa and the temperature at 110°C. The reaction was maintained at this temperature for 3 h. Then propylene oxide was introduced, and the reaction pressure was controlled at 0.3 MPa and the temperature at 120°C. The reaction was maintained at this temperature for 2 h. Then the temperature was lowered to below 60°C, glacial acetic acid was added, and the pH of the system was adjusted to 7.5. The mixture was stirred for 30 min and then distilled under reduced pressure to obtain hydroxyl-branched star-shaped polyether. The mass ratio of pentaerythritol, potassium hydroxide, ethylene oxide, and propylene oxide was 10:0.3:50:30.

[0043] 3. The isocyanate silane grafted modified wetting agent and hydroxyl multibranched star-shaped polyether are compounded at a mass ratio of 1:2.5 and stirred evenly to obtain the modified compound wetting agent.

[0044] 4. Under a nitrogen atmosphere, for surfaces with a specific surface area ≥180m² 2 / g of CoO-MoO3 / SiO2, tert-butylamine trisulfide, alkylnaphthalene and modified compound wetting agent are added to the vulcanizing furnace. The vulcanizing furnace is rotated at a rate of 10 rpm and stirred for 40 min. The mixture is heated to 160℃ at a rate of 1.5℃ / min and held for 2 h.

[0045] 5. Stop the nitrogen supply and introduce hydrogen into the furnace to replace the nitrogen, circulating the hydrogen at a pressure of 0.4 MPa and a flow rate of 10 m³ / h. 3Elemental sulfur is added to the furnace in three portions, with a 30-minute interval between each addition. After the addition is complete, the temperature is raised to 375°C at a rate of 1.5°C / min and held for 5 hours.

[0046] 6. After vulcanization, the temperature is lowered to 220℃ at a rate of 1.5℃ / min. Nitrogen gas is introduced into the furnace to replace the hydrogen gas. After replacement, a mixture of nitrogen and oxygen gas is introduced, with an oxygen volume fraction of 0.5% and a flow rate of 5m³ / min. 3 The temperature was then decreased to 150°C at a rate of 1°C / min, and a mixture of nitrogen and oxygen was introduced, with an oxygen volume fraction of 2% and a flow rate of 5 m³ / min. 3 The dibutyl phthalate was atomized and sprayed into the vulcanizing furnace at a spray rate of 0.7 kg / h for 1.5 h passivation; then the temperature was lowered to 80°C at a rate of 1°C / min, and a mixture of nitrogen and oxygen was introduced, with an oxygen volume fraction of 5% and a flow rate of 5 m³ / h. 3 / h, passivate for 1.2h, after passivation, cool to room temperature, remove the hydrogenation catalyst, and obtain the presulfurized hydrogenation catalyst prepared by the method described in Example 1.

[0047] The mass ratio of the hydrogenation catalyst, tert-butylamine trisulfide, alkylnaphthalene, modified compound wetting agent, elemental sulfur, and dibutyl phthalate in steps 4-6 is 100:10:5:0.35:6:2.

[0048] Example 4 like Figure 1 As shown, a presulfurization treatment method for a hydrogenation catalyst includes the following steps: 1. Polyethylene glycol monomethyl ether with a molecular weight of 400 and anhydrous toluene were added to a reaction vessel, stirred, and heated to 60°C. The mixture was then dehydrated under vacuum to obtain a transparent solution. The temperature was lowered to 43°C, and dibutyltin dilaurate and 2,6-di-tert-butyl-p-cresol were added. The mixture was stirred for 12 min, and γ-isocyanate propyltriethoxysilane was added dropwise at a rate of 1 drop / s. The temperature was then raised to 63°C and the reaction was maintained at this temperature for 3.5 h. After the reaction was completed, the mixture was distilled under reduced pressure to obtain an isocyanate silane graft-modified wetting agent. The mass ratio of polyethylene glycol monomethyl ether, anhydrous toluene, dibutyltin dilaurate, 2,6-di-tert-butyl-p-cresol, and γ-isocyanate propyltriethoxysilane was 100:50:0.1:0.01:10.

[0049] 2. Pentaerythritol and potassium hydroxide were added to a reaction vessel. Under nitrogen atmosphere, the mixture was stirred and heated to 125°C, kept at this temperature for 1 hour to remove moisture, then cooled to 85°C. Ethylene oxide was introduced, and the reaction pressure was controlled at 0.25 MPa and the temperature at 105°C. The reaction was maintained at this temperature for 3.5 hours. Then propylene oxide was introduced, and the reaction pressure was controlled at 0.25 MPa and the temperature at 115°C. The reaction was maintained at this temperature for 2.5 hours. The temperature was then lowered to below 60°C, glacial acetic acid was added, and the pH of the system was adjusted to 7. The mixture was stirred for 35 minutes and then distilled under reduced pressure to obtain hydroxyl-branched star-shaped polyether. The mass ratio of pentaerythritol, potassium hydroxide, ethylene oxide, and propylene oxide was 10:0.2:50:25.

[0050] 3. The isocyanate silane grafted modified wetting agent and hydroxyl multibranched star-shaped polyether are compounded at a mass ratio of 1:2 and stirred evenly to obtain the modified compound wetting agent.

[0051] 4. Under a nitrogen atmosphere, for surfaces with a specific surface area ≥180m² 2 / g of NiO-WO3 / Al2O3, tert-butylamine tetrasulfide, methylnaphthalene and modified compound wetting agent are added to the vulcanizing furnace. The vulcanizing furnace is rotated at a rate of 5 rpm and stirred for 35 min. The mixture is heated to 150℃ at a rate of 1.2℃ / min and held at that temperature for 1.7 h.

[0052] 5. Stop the nitrogen supply and introduce hydrogen into the furnace to replace the nitrogen, thus initiating hydrogen circulation at a pressure of 0.35 MPa and a flow rate of 9 m³ / h. 3 Elemental sulfur is added to the furnace in three portions, with a 30-minute interval between each addition. After the addition is complete, the temperature is raised to 350°C at a rate of 1.2°C / min and held for 5.5 hours.

[0053] 6. After vulcanization, the temperature is lowered to 200℃ at a rate of 1.2℃ / min. Nitrogen gas is introduced into the furnace to replace the hydrogen gas. After replacement, a mixture of nitrogen and oxygen gas is introduced, with an oxygen volume fraction of 0.3% and a flow rate of 4.5m³. 3 The temperature was then decreased to 130℃ at a rate of 0.9℃ / min, and a mixture of nitrogen and oxygen was introduced at a flow rate of 4.5 m³ / min, with an oxygen volume fraction of 1.5%. 3 The dibutyl phthalate was atomized and sprayed into the vulcanizing furnace at a spray rate of 0.8 kg / h for 1.8 h passivation. Then, the temperature was lowered to 70 °C at a rate of 0.9 °C / min, and a mixture of nitrogen and oxygen was introduced, with an oxygen volume fraction of 4% and a flow rate of 4.5 m³ / min. 3 / h, passivate for 1.3h, after passivation, cool to room temperature, remove the hydrogenation catalyst, and obtain the presulfurized hydrogenation catalyst prepared by the method described in Example 1.

[0054] The mass ratio of the hydrogenation catalyst, tert-butylamine tetrasulfide, methylnaphthalene, modified compound wetting agent, elemental sulfur, and dibutyl phthalate in steps 4-6 is 100:8:5:0.2:5:1.

[0055] Example 5 like Figure 1 As shown, a presulfurization treatment method for a hydrogenation catalyst includes the following steps: 1. Polyethylene glycol monomethyl ether with a molecular weight of 400 and anhydrous toluene were added to a reaction vessel, stirred, and heated to 60°C. The mixture was then dehydrated under vacuum to obtain a transparent solution. The temperature was lowered to 43°C, and dibutyltin dilaurate and 2,6-di-tert-butyl-p-cresol were added. The mixture was stirred for 12 min, and γ-isocyanate propyltriethoxysilane was added dropwise at a rate of 1 drop / s. The temperature was then raised to 63°C and the reaction was maintained at this temperature for 3.5 h. After the reaction was completed, the mixture was distilled under reduced pressure to obtain an isocyanate silane graft-modified wetting agent. The mass ratio of polyethylene glycol monomethyl ether, anhydrous toluene, dibutyltin dilaurate, 2,6-di-tert-butyl-p-cresol, and γ-isocyanate propyltriethoxysilane was 100:55:0.08:0.015:11.

[0056] 2. Pentaerythritol and potassium hydroxide were added to a reaction vessel. Under nitrogen atmosphere, the mixture was stirred and heated to 125°C, kept at this temperature for 1 hour to dehydrate, then cooled to 85°C. Ethylene oxide was introduced, and the reaction pressure was controlled at 0.25 MPa and the temperature at 105°C. The reaction was maintained at this temperature for 3.5 hours. Then propylene oxide was introduced, and the reaction pressure was controlled at 0.25 MPa and the temperature at 115°C. The reaction was maintained at this temperature for 2.5 hours. The temperature was then lowered to below 60°C, glacial acetic acid was added, and the pH of the system was adjusted to 7. The mixture was stirred for 35 minutes and then distilled under reduced pressure to obtain hydroxyl-branched star-shaped polyether. The mass ratio of pentaerythritol, potassium hydroxide, ethylene oxide, and propylene oxide was 10:0.25:45:25.

[0057] 3. The isocyanate silane grafted modified wetting agent and hydroxyl multibranched star-shaped polyether are compounded at a mass ratio of 1:2.5 and stirred evenly to obtain the modified compound wetting agent.

[0058] 4. Under a nitrogen atmosphere, for surfaces with a specific surface area ≥180m² 2 / g of NiO-WO3 / Al2O3, dimethyl disulfide, dodecylbenzene and modified compound wetting agent are added to the vulcanizing furnace. The vulcanizing furnace is rotated at a rate of 5 rpm and stirred for 35 min. The mixture is heated to 150℃ at a rate of 1.2℃ / min and held at that temperature for 1.7 h.

[0059] 5. Stop the nitrogen supply and introduce hydrogen into the furnace to replace the nitrogen, thus initiating hydrogen circulation at a pressure of 0.35 MPa and a flow rate of 9 m³ / h. 3Elemental sulfur is added to the furnace in three portions, with a 30-minute interval between each addition. After the addition is complete, the temperature is raised to 350°C at a rate of 1.2°C / min and held for 5.5 hours.

[0060] 6. After vulcanization, the temperature is lowered to 200℃ at a rate of 1.2℃ / min. Nitrogen gas is introduced into the furnace to replace the hydrogen gas. After replacement, a mixture of nitrogen and oxygen gas is introduced, with an oxygen volume fraction of 0.3% and a flow rate of 4.5m³. 3 The temperature was then decreased to 130℃ at a rate of 0.9℃ / min, and a mixture of nitrogen and oxygen was introduced at a flow rate of 4.5 m³ / min, with an oxygen volume fraction of 1.5%. 3 The dibutyl phthalate was atomized and sprayed into the vulcanizing furnace at a spray rate of 0.9 kg / h for 1.8 h passivation. Then, the temperature was lowered to 70 °C at a rate of 0.9 °C / min, and a mixture of nitrogen and oxygen was introduced, with an oxygen volume fraction of 4% and a flow rate of 4.5 m³ / min. 3 / h, passivate for 1.3h, after passivation, cool to room temperature, remove the hydrogenation catalyst, and obtain the presulfurized hydrogenation catalyst prepared by the method described in Example 1.

[0061] The mass ratio of hydrogenation catalyst, dimethyl disulfide, dodecylbenzene, modified compound wetting agent, elemental sulfur, and dibutyl phthalate in steps 4-6 is 100:8:4:0.2:5:1.5.

[0062] Comparative Example 1 This comparative example provides a pre-sulfurization treatment method for a hydrogenation catalyst. The difference from Example 1 is that polyethylene glycol monomethyl ether is not grafted with isocyanate silane during the preparation process. The remaining steps are the same as in Example 1 and will not be repeated here.

[0063] Comparative Example 2 This comparative example provides a pre-sulfurization treatment method for a hydrogenation catalyst. The difference from Example 1 is that ammonium trisulfide is not added during the preparation process. The remaining steps are the same as in Example 1 and will not be repeated here.

[0064] Comparative Example 3 This comparative example provides a presulfurization treatment method for a hydrogenation catalyst. Compared with Example 1, the difference is that the segmented passivation process is not used in the preparation process, but the passivation is completed directly in one step. The remaining steps are the same as in Example 1, and will not be repeated here.

[0065] To demonstrate the beneficial effects of the presulfurized hydrogenation catalyst prepared by the method of this application, performance tests were conducted on Examples 1-5 and Comparative Examples 1-3, and the test methods are as follows: Catalyst activity evaluation: A 200mL fixed-bed hydrotreating device was used for testing. A pre-sulfurized hydrotreating catalyst sample was added to the device, air was purged with nitrogen, followed by hydrogen purging to replace the nitrogen, and the temperature was raised to 260℃ and held for 2 hours. The temperature was then lowered to 160℃, feedstock oil was added, and the temperature was raised to 350℃ and held for 8 hours before sampling and analysis. The HDS (hydrodesulfurization activity) and HDN (hydronitrogenation activity) of the pre-sulfurized hydrotreating catalyst were obtained. The test results are shown in Table 1.

[0066] Catalyst exothermic experiment: 50g of pre-sulfurized hydrogenation catalyst sample was placed in a self-heating substance tester, heated to 150℃, and kept at that temperature for 3 hours to investigate the exothermic behavior of the catalyst in air. The test results are shown in Table 2.

[0067] Table 1. Catalyst activity evaluation results for Examples 1-5 and Comparative Examples 1-3

[0068] Table 2. Results of catalyst exothermic experiments in Examples 1-5 and Comparative Examples 1-3

[0069] As shown in Table 1, the hydrodesulfurization and hydronitrogenation activities of Examples 1-5 are superior to those of Comparative Examples 1-3. This indicates that the method provided in this application can effectively improve the pre-sulfurization effect of the hydrodesulfurization catalyst and enhance its reactivity. Specifically, in Comparative Example 1, the absence of polyethylene glycol monomethyl ether grafted with isocyanate silane during preparation resulted in the wetting agent failing to stably anchor on the catalyst surface, reducing its ability to guide the sulfiding agent to wet the catalyst surface and leading to a poorer sulfidation effect, thus decreasing the catalyst's activity. In Comparative Example 2, the lack of ammonium trisulfide addition during preparation resulted in the catalyst not undergoing preliminary wetting and sulfidation, leading to a violent reaction during subsequent sulfidation and the destruction of some active sites, thus reducing the catalyst's activity. In Comparative Example 3, the absence of a segmented passivation method during preparation may have resulted in poor passivation, causing some active sites of the catalyst to be oxidized and deactivated in air, leading to a decrease in its catalytic activity.

[0070] As can be seen from the test results in Table 2, the catalysts prepared in Examples 1-5 and Comparative Examples 1-2 have good passivation effects and no oxidation heating problem. However, Comparative Example 3 may have poor passivation effect due to the lack of a segmented passivation process, and the active sites may be oxidized by air, resulting in heating problems.

[0071] In summary, the pre-sulfurization treatment method for hydrogenation catalysts provided in this application can effectively improve the sulfidation and passivation effects of the catalysts, ensure the safe storage and transportation of the pre-sulfurized catalysts, and serve as a ready-to-use hydrogenation catalyst, reducing the feedstock processing flow and improving production efficiency.

[0072] It should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application, and all such modifications and substitutions should be covered within the scope of the claims of this application.

Claims

1. A method for presulfurizing a hydrogenation catalyst, characterized in that, Includes the following steps: Under a nitrogen atmosphere, hydrogenation catalyst, sulfiding agent a, dispersant and modified compound wetting agent are added to the sulfidation furnace, the sulfidation furnace is rotated, the mixture is pre-wetted; Stop the nitrogen supply, introduce hydrogen into the furnace to replace the nitrogen, and circulate the hydrogen. Add the vulcanizing agent b into the furnace and heat up the vulcanizing process. After sulfidation, the temperature is lowered, and nitrogen is introduced into the furnace to replace the hydrogen for staged passivation. After passivation, the furnace is cooled to room temperature, and the hydrogenation catalyst is removed to obtain the pre-sulfided hydrogenation catalyst. The modified compound wetting agent is obtained by compounding an isocyanate silane grafted modified wetting agent with a hydroxyl multibranched star-shaped polyether; The wetting agent is polyethylene glycol monomethyl ether; The hydroxyl-branched star-shaped polyether is obtained by ring-opening polymerization of pentaerythritol with ethylene oxide and propylene oxide.

2. The presulfurization treatment method for a hydrogenation catalyst according to claim 1, characterized in that, The vulcanizing agent a includes any one of ammonium trisulfide, ammonium tetrasulfide, tert-butylamine trisulfide, tert-butylamine tetrasulfide, and dimethyl disulfide; the vulcanizing agent b is elemental sulfur.

3. The presulfurization treatment method for a hydrogenation catalyst according to claim 1, characterized in that, The dispersant includes any one of dodecylbenzene, tetradecylbenzene, alkylnaphthalene, and methylnaphthalene.

4. The presulfurization treatment method for a hydrogenation catalyst according to claim 1, characterized in that, The rotation speed of the rotary vulcanizing furnace is 2-10 rpm; the specific steps of the pre-impregnation are as follows: after the vulcanizing furnace is rotated and stirred for 30-40 min, the temperature is increased to 140-160℃ at a rate of 1-1.5℃ / min, and the temperature is maintained for 1.5-2 h to complete the pre-impregnation.

5. The presulfurization treatment method for a hydrogenation catalyst according to claim 1, characterized in that, The specific preparation steps of the modified compound wetting agent are as follows: Polyethylene glycol monomethyl ether with a molecular weight of 350-450 and anhydrous toluene were added to a reaction vessel, stirred, and heated to 55-65°C. The mixture was then dehydrated under vacuum to obtain a transparent solution. The temperature was lowered to 40-45°C, and dibutyltin dilaurate and 2,6-di-tert-butyl-p-cresol were added. The mixture was stirred for 10-15 minutes, and γ-isocyanate propyltriethoxysilane was added dropwise at a rate of 1 drop / s. The temperature was then raised to 60-65°C, and the reaction was carried out at a constant temperature for 3-4 hours. After the reaction was completed, the mixture was distilled under reduced pressure to obtain the isocyanate silane grafted modified wetting agent. Pentaerythritol and potassium hydroxide were added to a reactor. Under nitrogen atmosphere, the mixture was stirred and heated to 120-130℃, and kept at this temperature for dehydration for 0.8-1.2 hours. The temperature was then lowered to 80-90℃, and ethylene oxide was introduced. The reaction pressure was controlled at 0.2-0.3 MPa, and the temperature at 100-110℃. The reaction was kept at this temperature for 3-4 hours. Then, propylene oxide was introduced. The reaction pressure was controlled at 0.2-0.3 MPa, and the temperature at 110-120℃. The reaction was kept at this temperature for 2-3 hours. The temperature was then lowered to below 60℃, and glacial acetic acid was added to adjust the pH of the system to 6.5-7.

5. The mixture was stirred for 30-40 minutes and then distilled under reduced pressure to obtain hydroxyl-branched star-shaped polyether. The isocyanate silane grafted modified wetting agent and hydroxyl multibranched star-shaped polyether were compounded at a mass ratio of 1:(1.5-2.5) and stirred evenly to obtain the modified compound wetting agent.

6. The presulfurization treatment method for a hydrogenation catalyst according to claim 5, characterized in that, The mass ratio of polyethylene glycol monomethyl ether, anhydrous toluene, dibutyltin dilaurate, 2,6-di-tert-butyl-p-cresol, and γ-isocyanate propyltriethoxysilane is 100:(50-60):(0.05-0.1):(0.01-0.02):(10-12); the mass ratio of pentaerythritol, potassium hydroxide, ethylene oxide, and propylene oxide is 10:(0.2-0.3):(40-50):(20-30).

7. The presulfurization treatment method for a hydrogenation catalyst according to claim 1, characterized in that, The hydrogen circulation system operates at a pressure of 0.3-0.4 MPa and a flow rate of 8-10 m³ / s. 3 / h; the vulcanizing agent b is added to the reactor in three batches, with a 30-minute interval between each batch; the specific process of the heating and vulcanization is as follows: the temperature is increased to 300-375℃ at a rate of 1-1.5℃ / min, and the temperature is maintained for 5-6 hours.

8. The presulfurization treatment method for a hydrogenation catalyst according to claim 1, characterized in that, The specific process of lowering the temperature is as follows: the temperature is lowered to 180-220℃ at a rate of 1-1.5℃ / min.

9. The presulfurization treatment method for a hydrogenation catalyst according to claim 1, characterized in that, The specific process of segmented passivation is as follows: after nitrogen gas is introduced to replace hydrogen gas, a mixture of nitrogen and oxygen gas is introduced, with an oxygen volume fraction of 0.2-0.5% and a flow rate of 4-5 m³ / h. 3 The first stage of passivation lasts 1.2-1.5 hours; the temperature is then lowered to 120-150°C at a rate of 0.8-1°C / min, and a mixture of nitrogen and oxygen is introduced, with an oxygen volume fraction of 1-2% and a flow rate of 4-5 m³ / min. 3 The dibutyl phthalate is atomized and sprayed into the vulcanizing furnace at a rate of 0.8-1℃ / min, and the second stage of passivation lasts for 1.5-2 hours. The temperature is then further reduced to 60-80℃ at a rate of 0.8-1℃ / min, and a mixture of nitrogen and oxygen is introduced, with an oxygen volume fraction of 3-5% and a flow rate of 4-5 m³ / min. 3 / h, the third stage passivation lasts 1.2-1.5h.

10. The presulfurization treatment method for a hydrogenation catalyst according to claim 9, characterized in that, The mass ratio of the hydrogenation catalyst, sulfiding agent a, dispersant, modified compound wetting agent, sulfiding agent b, and dibutyl phthalate is 100:(8-10):(3-5):(0.15-0.35):(4-6):(1-2).

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