Passivation of hydrogenation catalysts

Abstract

The application provides a passivation method of a hydrogenation catalyst, comprising the following steps: passivating a sulfided hydrogenation catalyst by using a carbon-containing passivation agent; wherein the carbon-containing passivation agent comprises at least two of carbon dioxide, a low-carbon alkane, a low-carbon alkene and a low-carbon alkyne. The passivation treatment by using the carbon-containing passivation agent enables carbon to be deposited on the surface of the catalyst, so as to coat the active sites, ensure the safety of the sulfided hydrogenation catalyst, and ensure that the activity of the catalyst is not reduced.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a passivation method for hydrogenation catalysts. Background Technology

[0002] With the trend towards heavier and lower-quality crude oil, and increasingly stringent quality standards for clean petroleum products, achieving clean production and efficient conversion using hydrotreating technology is a major challenge for refineries. Hydrotreating catalysts are the core of hydrotreating technology. To improve the hydrotreating activity, selectivity, and stability of hydrotreating catalysts, and to extend their lifespan and the operating cycle of hydrotreating units, oxidized hydrotreating catalysts are typically sulfided. However, sulfided catalysts exposed to air and encountering O2 will generate SO2 and heat, posing a risk of spontaneous combustion below 200°C, and presenting safety risks during packaging, storage, and transportation. Therefore, passivation of sulfided catalysts is essential.

[0003] Currently, passivation technologies are mainly divided into gas-phase passivation and liquid-phase passivation. For example, patent document CN103059969B discloses a start-up passivation method for a hydrocracking catalyst, which introduces a high-nitrogen feedstock during the catalyst passivation stage and uses ammonia gas generated from hydrogenation as a passivating agent. The drawbacks of this technology are: the passivation process is complex, the degree of passivation is difficult to control, and it is mainly applicable to hydrocracking catalysts containing molecular sieves.

[0004] Patent document CN109675643A discloses a method for preparing a sulfide catalyst, the sulfide catalyst itself, and its applications. This method uses distillate oil and oxygen-containing substances for passivation. This type of passivation leads to the permanent loss of some active sites on the catalyst, which cannot be recovered, thus affecting catalytic activity. In addition, the process is complex and not conducive to large-scale application.

[0005] Patent document CN106179522B discloses an external pre-sulfurization method for a hydrogenation catalyst. The passivating agent used contains component A and component B. Component A is one or more of ethylene glycol, propanolamine, propanol, and butanol, and component B is one or more of urea, glycerol, and acrylamide. This method results in a significant loss of hydrogenation catalyst activity after passivation.

[0006] In existing technologies, gas-phase passivation mainly uses oxygen-containing gas to passivate sulfide-state catalysts, causing some of the sulfur in the sulfide-state catalyst to be replaced by oxygen, forming metal oxysulfides. Gas-phase passivation easily leads to the permanent deactivation of some active sites of the catalyst, resulting in poor applicability. Liquid-phase passivation mainly uses methods such as impregnation and coating. For example, a protective liquid containing organic oxygen-containing hydrocarbons is uniformly sprayed onto the surface of a solid catalyst at a temperature lower than the freezing point of the protective liquid, causing the protective liquid to crystallize and form a solid protective film. Alternatively, heavy hydrocarbons (such as vacuum distillate oil) can be used, with hot hydrocarbons sprayed onto the surface of a low-temperature catalyst. The increased viscosity of the hydrocarbons slows down their diffusion rate towards the particle center, thereby encapsulating the catalyst and isolating its surface from air. The problems with liquid-phase passivation are that it requires a large amount of protective liquid, resulting in high cost; a protective film that is too thick will affect the recovery of catalyst activity, while a film that is too thin will not effectively isolate oxygen, and the thickness of the protective film is difficult to control precisely.

[0007] Therefore, how to provide a passivation method that is low in cost, has a wide range of applications, and can ensure that the catalyst activity is not reduced is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] This invention provides a passivation method for hydrogenation catalysts, which uses a carbon-containing passivating agent to passivate the catalyst surface, thereby coating the active sites and ensuring the safety of the sulfide-state hydrogenation catalyst. It also ensures that the catalyst activity is not reduced, and has the advantages of wide applicability and low cost.

[0009] This invention provides a passivation method for a hydrogenation catalyst, comprising the following steps: passivating a sulfide-state hydrogenation catalyst with a carbon-containing passivating agent; wherein the carbon-containing passivating agent comprises at least two of carbon dioxide, low-carbon alkanes, low-carbon olefins, and low-carbon alkynes.

[0010] According to one embodiment of the present invention, the low-carbon alkane is selected from C1-C5 alkanes; the low-carbon olefin is selected from C2-C6 olefins; and the low-carbon alkyne is selected from C2-C5 alkynes.

[0011] According to one embodiment of the present invention, the passivation treatment conditions are: temperature 350°C to 460°C, pressure 0.5 MPa to 3.5 MPa, and volume hourly space velocity (VHSV) 500 h⁻¹. -1 ~10000h -1 The passivation time is 2 hours to 10 hours.

[0012] According to one embodiment of the present invention, the sulfide-state hydrogenation catalyst is contacted with a mixture of an inert gas and a carbon-containing passivating agent to perform the passivation treatment; in the mixture, the volume concentration of the carbon-containing passivating agent is 1%-10%.

[0013] According to one embodiment of the present invention, after passivation treatment, the process further includes cooling the passivated sulfide hydrogenation catalyst under an inert atmosphere to a temperature of 0–50°C.

[0014] According to one embodiment of the present invention, the sulfide-state hydrogenation catalyst is prepared by the following steps: the oxidized hydrogenation catalyst is impregnated and sulfided in a solution containing sulfur compounds, and then activated by passing hydrogen gas to obtain the sulfide-state hydrogenation catalyst.

[0015] According to one embodiment of the present invention, the sulfur-containing compound is at least one of ammonium sulfide, ammonium thiosulfate, sulfur, and thiols.

[0016] According to one embodiment of the present invention, after impregnation and vulcanization, the impregnated product is further dried under the following conditions: temperature 50°C to 150°C, time 2h to 6h.

[0017] According to one embodiment of the present invention, the activation conditions are: temperature 200℃~320℃, pressure 1.5MPa~3.5MPa, volume hourly space velocity 6000h-1~13000h-1, and time 2h~8h.

[0018] According to one embodiment of the present invention, the oxidized catalyst comprises a support and an active metal supported on the support, wherein the active metal comprises at least one metallic element from Groups VIB and VIII of the periodic table, and the support comprises at least one from the following: alumina, zirconium oxide, silicon dioxide, activated carbon, diatomaceous earth, and zeolite.

[0019] The implementation of this invention has at least the following beneficial effects:

[0020] The passivation method for hydrogenation catalysts provided by this invention employs a carbon-containing passivating agent to passivate the catalyst surface, resulting in carbon deposition that coats the active sites. This ensures that the active sites of the sulfide-state catalyst are not directly exposed to air, improving safety. Furthermore, it ensures that the catalyst activity does not decrease. When this passivated sulfide-state hydrogenation catalyst is applied in hydrogenation processes, the carbon deposits on the catalyst surface are dissipated as the reaction temperature increases, promoting the release of active sites without generating secondary pollution. This method offers advantages such as wide applicability and low cost. Detailed Implementation

[0021] The specific embodiments listed below are merely descriptions of the principles and features of the present invention. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The passivation method for hydrogenation catalysts provided by the present invention includes the following steps: passivating the sulfide-state hydrogenation catalyst with a carbon-containing passivating agent; wherein the carbon-containing passivating agent includes at least two of carbon dioxide, low-carbon alkanes, low-carbon olefins, and low-carbon alkynes.

[0023] This invention does not limit the sulfurized hydrogenation catalyst, including but not limited to hydrogenation catalysts used in hydrocracking, hydrodesulfurization, hydrorefining, and hydrogenation processes of kerosene, wax oil, naphtha, and cracked gasoline.

[0024] The sulfidated catalyst can be obtained by sulfiding an oxidized hydrogenation catalyst with a sulfur-containing compound. During the sulfidation process, the oxidized active metal in the oxidized hydrogenation catalyst is converted into a sulfidated state.

[0025] Since the active metal components in the sulfide-state hydrogenation catalyst exist in the sulfide state and have high activity, this invention uses a carbon-containing passivating agent to passivate the sulfide-state catalyst, which can make the metal active sites on the surface of the sulfide-state catalyst covered by carbon deposits, suppressing its high activity in the early stage and achieving passivation.

[0026] The carbon-containing passivating agent includes at least two of carbon dioxide, low-carbon alkanes, low-carbon olefins, and low-carbon alkynes. For example, the carbon-containing passivating agent can be any two, any three, or any four of carbon dioxide, low-carbon alkanes, low-carbon olefins, and low-carbon alkynes. It should be noted that the number of carbon atoms in each of the low-carbon alkanes, low-carbon olefins, and low-carbon alkynes is usually no more than 4.

[0027] According to the technical solution of the present invention, a specific type of carbon-containing passivating agent is used to passivate the sulfide-state hydrogenation catalyst. The metal active sites are coated with carbon, which passivates the catalyst surface, reduces activity loss, improves stability, and ensures the safety of storage, transportation and start-up. At the same time, the present invention makes full use of the characteristic that carbon deposition does not cause catalyst deactivation. During the heating process of hydrogenation, the carbon deposition is gradually dissolved by hydrogen gas, releasing the active sites again and ensuring that the catalytic activity does not decrease.

[0028] In this invention, the carbon-containing passivating agent is preferably a gaseous passivating agent, which facilitates sufficient contact between the sulfurized catalyst and the carbon-containing passivating agent. In some embodiments, the low-carbon alkane can be a C1-C5 alkane, such as at least one of methane, ethane, propane, butane, and pentane; the low-carbon olefin can be a C2-C6 olefin, such as at least one of ethylene, propylene, butene, pentene, and hexene; and the low-carbon alkyne can be a C2-C5 alkyne, such as at least one of acetylene, propyne, butyne, and pentyne. Preferably, it is a C1-C4 alkane; the low-carbon olefin is selected from C2-C4 olefins; and the low-carbon alkyne is selected from C2-C4 alkynes.

[0029] According to the technical solution of the present invention, by using a carbon-containing passivating agent that meets the above requirements, carbon deposits can be coated on the surface of the active sites of the sulfide-state hydrogenation catalyst. These carbon deposits can be filamentous carbon, graphite carbon, or spherical coated carbon. The carbon deposits can be decomposed under the conditions of hydrogen and the hydrogenation reaction temperature. Therefore, the passivated sulfide-state hydrogenation catalyst can be directly applied in the hydrogenation process. The surface carbon decomposes under the conditions of hydrogen and the hydrogenation reaction temperature, allowing the metal active sites of the sulfide-state catalyst to be released again.

[0030] The passivation treatment described above is a gas-solid phase reaction process that can be carried out in reactors such as fluidized beds, fixed beds, spouted beds, and moving beds. For example, a granular catalyst is packed into the reactor to form a fixed bed of a certain height. A carbon-containing passivating agent is then introduced into the reactor, and passivation is achieved as the carbon-containing passivating agent flows through the fixed bed.

[0031] The present invention does not limit the passivation conditions, as long as carbon deposition is formed on the surface of the sulfide catalyst. In some embodiments, the passivation temperature is 350°C to 460°C, for example, 350°C, 360°C, 380°C, 400°C, 410°C, 420°C, 430°C, 460°C or any combination thereof, and the passivation pressure is 0.5MPa to 3.5MPa, for example, preferably 0.5MPa, 1MPa, 1.5MPa, 2MPa, 2.5MPa, 3MPa, 3.5MPa or any combination thereof.

[0032] By properly controlling the amount of carbon-containing passivating agent, the amount of carbon deposited on the surface of the sulfide catalyst can be controlled. In some embodiments, the volume hourly space velocity (HHSV) for passivation treatment is 500 h⁻¹. -1 ~10000h -1 For example, 500h -1 1000h -1 2000h -1 3000h -1 4000h -1 5000h -1 6000h -1 7000h -1 8000h -1 10000h -1 The passivation time is a range of 2h to 10h, for example, 2h, 4h, 6h, 8h, 10h, or any combination thereof. The volume hourly space velocity (VHSV) refers to the VHSV of the carbon-containing passivating agent, i.e., the volume of carbon-containing passivating agent passing through a unit volume of sulfide-state catalyst per unit time.

[0033] To ensure the safety of the passivation treatment, the sulfide-state hydrogenation catalyst can be contacted with a mixture of inert gas and carbon-containing passivating agent. The inert gas includes at least one of helium and nitrogen. While the inert gas does not participate in the reaction, its presence causes a decrease in the partial pressure of the carbon-containing passivating agent in the syngas, thus affecting the reaction rate. Therefore, an appropriate amount of inert gas can be added as needed. In some embodiments, the volume concentration of the carbon-containing passivating agent in the mixture is 1%-10%, for example, a range of 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, or any combination thereof.

[0034] After the passivation treatment described above, a cooling process is performed under an inert atmosphere until the temperature drops to 0–50°C, yielding the passivated sulfide-state hydrogenation catalyst. The inert atmosphere can be nitrogen.

[0035] This invention allows for the preparation of sulfide-state hydrogenation catalysts using conventional methods. Typically, oxidized hydrogenation catalysts are used as raw materials and subjected to sulfidation treatment, causing the active components existing in the oxidized form of the oxidized hydrogenation catalyst to transform into sulfide-state active components.

[0036] This invention does not limit the sulfidation treatment. Depending on the location where the sulfidation reaction takes place, sulfidation can be divided into in-reactor sulfidation and out-of-reactor sulfidation. Out-of-reactor sulfidation refers to introducing the sulfiding agent into the pores of the oxidized hydrogenation catalyst by sublimation, melting, or impregnation before loading the oxidized hydrogenation catalyst into the reactor, allowing it to combine with the sulfiding agent. Then, the catalyst is loaded into the reactor, and hydrogen gas or hydrogen gas and oil are introduced simultaneously. Sulfidation activation is completed as the temperature rises.

[0037] In the specific implementation of this invention, the sulfide-state hydrogenation catalyst is prepared by the following steps: the oxidized hydrogenation catalyst is impregnated and sulfided in a solution containing sulfur compounds, and then activated by passing hydrogen gas to obtain the sulfide-state hydrogenation catalyst.

[0038] In the above specific implementation process, the sulfur-containing compound can be introduced into the pores of the oxidized hydrogenation catalyst by the equal volume impregnation method. After impregnation, the impregnation product is dried and then activated by hydrogen gas. This allows the sulfur-containing compound that has entered the pores of the oxidized hydrogenation catalyst to come into contact with hydrogen gas and decompose to generate hydrogen sulfide. At this time, the active component of the oxidized hydrogenation catalyst reacts with hydrogen sulfide to become the active component in the sulfide state.

[0039] The present invention does not limit the sulfur-containing compounds mentioned above, and can be one or more of any sulfides that can react with hydrogen to form hydrogen sulfide, such as at least one of ammonium sulfide, ammonium thiosulfate, sulfur, and thiols.

[0040] To further improve sulfidation efficiency, a saturated impregnation method can be used to impregnate the sulfidated hydrogenation catalyst. Typically, the amount of sulfur-containing compound added is controlled to be 110%–140% of the theoretical sulfur loading of the oxidized hydrogenation catalyst. The theoretical sulfur loading refers to the amount of sulfur-containing compound required to completely convert all the metal oxides (active components) on the oxidized hydrogenation catalyst into the corresponding sulfides. The impregnation process can be carried out under atmospheric pressure.

[0041] To remove excess moisture from the surface of the impregnated product, in some embodiments, after impregnation and vulcanization, the impregnated product is dried under the following conditions: temperature 50°C to 150°C, for example, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 120°C, 140°C, 150°C or any combination thereof; time 2h to 6h, for example, 2h, 4h, 6h or any combination thereof; and drying can be carried out under normal pressure.

[0042] The dried product was activated using hydrogen gas under the following conditions: temperature 200℃~320℃, for example, 200℃, 220℃, 260℃, 280℃, 300℃, 320℃ or any combination thereof; pressure 1.5MPa~3.5MPa, for example, 2MPa, 2.5MPa, 3MPa, 3.5MPa or any combination thereof; and volumetric hourly space velocity 6000 h⁻¹. -1 ~13000h -1 For example, 6000h -1 8000h -1 10000h -1 12000h -1 13000h -1 Or a range consisting of any two of them. Time range 2h to 8h, for example, 2h, 4h, 5h, 6h, 8h or a range consisting of any two of them.

[0043] This invention employs the aforementioned in-situ reaction to sulfide and activate the oxidized hydrogenation catalyst, eliminating the diffusion resistance of the oxidized hydrogenation catalyst, resulting in more complete sulfide activation and improved utilization of the active components. Furthermore, it avoids pollutant emissions, shortens start-up time, alleviates safety and environmental pressures, and improves economic efficiency.

[0044] This invention does not limit the above-mentioned oxidized hydrogenation catalyst. Generally, the oxidized catalyst includes a support and an active metal supported on the support. The active metal includes, but is not limited to, at least one metal element from Group VIB and Group VIII of the periodic table, wherein the active metal exists in the form of a metal oxide. The support includes, but is not limited to, at least one of alumina, zirconium oxide, silicon oxide, activated carbon, diatomaceous earth, and zeolite.

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0046] The present invention will be further described below through specific embodiments and comparative examples. Unless otherwise specified, the reagents, materials and instruments used below are all conventional reagents, materials and instruments, all of which are commercially available, and the reagents and materials involved can also be synthesized by conventional synthetic methods.

[0047] The equipment used in the following examples and comparative examples came from the following sources: a high-frequency infrared carbon-sulfur analyzer (Leco CS744), a sulfur-nitrogen analyzer (Analytikjena MultiEA 5000), a PONA gas chromatograph (Agilent 7890A), and a temperature-programmed sulfurization apparatus (Tianjin Xianquan, TPS-5096). The temperature-programmed sulfurization apparatus was used to sulfurize the oxidized hydrogenation catalyst. The sulfur-nitrogen analyzer was used to determine the sulfur content in the product to verify the hydrodesulfurization performance of the passivated catalyst. The PONA analyzer was used to determine the group composition and to detect the olefin saturation degree of the passivated catalyst, i.e., the hydrogenation saturation. Hydrogenation saturation is related to the octane number loss in gasoline products; the higher the hydrogenation saturation, the greater the octane number loss.

[0048] In the following examples and comparative examples, the support for the oxidized hydrodesulfurization catalyst used is alumina, the active components are cobalt oxide and molybdenum oxide, and the particle size is 20-40 mesh;

[0049] The following examples and comparative examples illustrate the passivation effect and hydrogenation activity evaluation methods for the passivated sulfide-state hydrodesulfurization catalysts:

[0050] 1. Passivation effect

[0051] Weigh 0.15 g to 0.2 g of the passivated sulfurized hydrodesulfurization catalyst and use a carbon-sulfur analyzer to detect the sulfur and carbon content on its surface; calculate the sulfur retention rate (%) and carbon deposition rate (%) according to the following formulas:

[0052] C(%) = 100 * (G / m) * F drift

[0053] C: Sulfur retention rate (%) or carbon deposit content (%);

[0054] G: Mass of the element being analyzed (g);

[0055] m: Sample mass (g);

[0056] F drift This is a coefficient value used to adjust instrument drift.

[0057] 2. Hydrogenation activity

[0058] Hydrodesulfurization: The hydrodesulfurization activity of the catalysts in the examples and comparative examples was evaluated using FCC gasoline with a sulfur content of 100 ppm to 125 ppm and an olefin content of 20% to 24% as feedstock. The reaction conditions were: temperature 280°C, pressure 2.0 MPa, and space velocity 2.5 h⁻¹. -1 The hydrogen-to-oil ratio was 300:1. After the reaction stabilized for 48 hours, samples were taken to determine the sulfur content and olefin content of the reaction products. The test results are shown in Table 1.

[0059] The formulas for calculating hydrodesulfurization activity and hydrogen saturation rate are as follows:

[0060]

[0061]

[0062] Example 1

[0063] (1) An equal volume of ammonium sulfide solution was used to impregnate the oxidized gasoline hydrodesulfurization catalyst, wherein the catalyst volume was 100 mL, the amount of ammonium sulfide solution added was 12 mL, and the concentration was 8%.

[0064] (2) The impregnated product was placed in a reactor for drying under the following conditions: temperature 80℃, time 2h; the reactor was then heated further, and hydrogen gas was introduced into the reactor to activate the impregnated product, thereby obtaining a sulfide-state hydrogenation catalyst; the activation conditions were: temperature 220℃, pressure 2.0MPa, volume hourly space velocity 6000h⁻¹. -1 Activation time: 3 hours;

[0065] (3) After activation, a mixture of inert gas and carbon-containing passivating agent is introduced into the reactor to passivate the sulfide-state hydrogenation catalyst. The carbon-containing passivating agent consists of methane, carbon dioxide, and propylene (volume ratio of 40:40:20). The total concentration of the carbon-containing passivating agent in the mixture is 7v%. The passivation conditions are: temperature 360℃, pressure 2.0MPa, and volume hourly space velocity 1000h. -1 The time was 4 hours; the reactor was heated at a rate of 20℃ / h.

[0066] After passivation, nitrogen gas is introduced into the reactor. When the temperature drops to 30°C, the passivated sulfurized gasoline hydrodesulfurization catalyst is unloaded and named C1.

[0067] Example 2

[0068] (1) An equal volume of ammonium thiosulfate solution was used to impregnate the oxidized gasoline hydrodesulfurization catalyst, wherein the volume of the catalyst was 100 mL, the amount of ammonium thiosulfate solution added was 10 mL, and the concentration was 10%.

[0069] (2) The impregnated product was placed in a reactor for drying under the following conditions: temperature 100℃, time 3h; the reactor was then heated further, and hydrogen gas was introduced into the reactor to activate the impregnated product, thereby obtaining a sulfide-state hydrogenation catalyst; the activation conditions were: temperature 260℃, pressure 2.5MPa, volume hourly space velocity 8000h⁻¹. -1 Activation time: 4 hours;

[0070] (3) After activation, a mixture of inert gas and carbon-containing passivating agent is introduced into the reactor to passivate the sulfide-state hydrogenation catalyst. The carbon-containing passivating agent is pentane and acetylene (in a ratio of 30:70). The concentration of the carbon-containing passivating agent in the mixture is 5v%. The passivation conditions are: temperature 380℃, pressure 3.0MPa, and volume hourly space velocity 5000h. -1 The time was 8 hours; the reactor was heated at a rate of 20℃ / h.

[0071] After passivation, nitrogen gas is introduced into the reactor. When the temperature drops to 30°C, the passivated sulfurized gasoline hydrodesulfurization catalyst is unloaded and named C2.

[0072] Example 3

[0073] (1) An equal volume impregnation of the oxidized gasoline hydrodesulfurization catalyst was carried out using a mixed solution of ammonium sulfide and sulfur, wherein the volume of the catalyst was 100 mL, the amount of the mixed solution of ammonium sulfide and sulfur added was 10 mL, and the concentration was 5%.

[0074] (2) The impregnated product was placed in a reactor for drying under the following conditions: temperature 120℃, time 4h; the reactor was then heated further, and hydrogen gas was introduced into the reactor to activate the impregnated product, thereby obtaining a sulfide-state hydrogenation catalyst; the activation conditions were: temperature 280℃, pressure 2.5MPa, volume hourly space velocity 8000h⁻¹. -1 Activation time: 5 hours;

[0075] (3) After activation, a mixture of inert gas and carbon-containing passivating agent is introduced into the reactor to passivate the sulfide-state hydrogenation catalyst. The carbon-containing passivating agent is carbon dioxide and hexene (in a ratio of 20:80). The concentration of the carbon-containing passivating agent in the mixture is 3v%. The passivation conditions are: temperature 400℃, pressure 1.5MPa, and volume hourly space velocity 10000h.-1 The time was 10 hours; the reactor was heated at a rate of 25℃ / h.

[0076] After passivation, nitrogen gas is introduced into the reactor. When the temperature drops to 20°C, the passivated sulfurized gasoline hydrodesulfurization catalyst is unloaded and named C3.

[0077] Example 4

[0078] (1) An equal volume impregnation of the oxidized gasoline hydrodesulfurization catalyst was carried out using a mixed solution of ammonium thiosulfate and sulfur, wherein the catalyst volume was 100 mL, the amount of the mixed solution of ammonium thiosulfate and sulfur added was 9 mL, and the concentration was 7%.

[0079] (2) The impregnated product was placed in a reactor for drying under the following conditions: temperature 140℃, time 5h; the reactor was then heated further, and hydrogen gas was introduced into the reactor to activate the impregnated product, thereby obtaining a sulfide-state hydrogenation catalyst; the activation conditions were: temperature 300℃, pressure 3MPa, volume hourly space velocity 10000h. -1 Activation time: 6 hours;

[0080] (3) After activation, a mixture of inert gas and carbon-containing passivating agent is introduced into the reactor to passivate the sulfide-state hydrogenation catalyst. The carbon-containing passivating agent is methane and carbon dioxide (in a ratio of 60:40). The concentration of the carbon-containing passivating agent in the mixture is 3v%. The passivation conditions are: temperature 410℃, pressure 3MPa, and volume hourly space velocity 5000h. -1 The time was 6 hours; the reactor was heated at a rate of 25℃ / h.

[0081] After passivation, nitrogen gas is introduced into the reactor. When the temperature drops to 20°C, the passivated sulfurized gasoline hydrodesulfurization catalyst is unloaded and named C4.

[0082] Example 5

[0083] (1) An equal volume of ammonium sulfide and ammonium thiosulfate mixed solution was used to impregnate the oxidized gasoline hydrodesulfurization catalyst, wherein the volume of the oxidized gasoline hydroretrograde catalyst was 100 mL, the amount of ammonium sulfide and ammonium thiosulfate mixed solution added was 13 mL, and the concentration was 10%.

[0084] (2) The impregnated product was placed in a reactor for drying under the following conditions: temperature 150℃, time 5h; the reactor was then heated further, and hydrogen gas was introduced into the reactor to activate the impregnated product, thereby obtaining a sulfide-state hydrogenation catalyst; the activation conditions were: temperature 320℃, pressure 3.5MPa, volume hourly space velocity 8000h⁻¹. -1 Activation time: 8 hours;

[0085] (3) After activation, a mixture of inert gas and carbon-containing passivating agent is introduced into the reactor to passivate the sulfide-state hydrogenation catalyst. The carbon-containing passivating agent is ethylene and propyne (in a ratio of 70:30). The concentration of the carbon-containing passivating agent in the mixture is 7v%. The passivation conditions are: temperature 410℃, pressure 3.5MPa, and volume hourly space velocity 5000h. -1 The time was 8 hours; the reactor was heated at a rate of 30℃ / h.

[0086] After passivation, nitrogen gas is introduced into the reactor. When the temperature drops to 20°C, the passivated gasoline hydrodesulfurization catalyst is unloaded and named C5.

[0087] Example 6

[0088] (1) An equal volume impregnation of the oxidized gasoline hydrodesulfurization catalyst was carried out using a mixed solution of ammonium sulfide and mercaptan, wherein the volume of the catalyst was 100 mL, the amount of the mixed solution of ammonium sulfide and mercaptan added was 15 mL, and the concentration was 8%.

[0089] (2) The impregnated product was placed in a reactor for drying under the following conditions: temperature 120℃, time 5h; the reactor was then heated further, and hydrogen gas was introduced into the reactor to activate the impregnated product, thereby obtaining a sulfide-state hydrogenation catalyst; the activation conditions were: temperature 300℃, pressure 3.0MPa, volume hourly space velocity 12000h⁻¹. -1 Activation time: 6 hours;

[0090] (3) After activation, a mixture of inert gas and carbon-containing passivating agent is introduced into the reactor to passivate the sulfide-state hydrogenation catalyst. The carbon-containing passivating agent consists of ethane, carbon dioxide, and pentyne (in a ratio of 30:20:50). The concentration of the carbon-containing passivating agent in the mixture is 8v%. The passivation conditions are: temperature 420℃, pressure 3.5MPa, and volume hourly space velocity (VHSV) 8000h. -1 The time was 10 hours; the reactor was heated at a rate of 30℃ / h.

[0091] After passivation, nitrogen gas is introduced into the reactor. When the temperature drops to 20°C, the passivated sulfurized gasoline hydrodesulfurization catalyst is unloaded and named C6.

[0092] Example 7

[0093] (1) An oxidized gasoline hydrodesulfurization catalyst was impregnated with a mixed solution of ammonium thiosulfate and mercaptan in equal volume, wherein the catalyst volume was 100 mL, the amount of the mixed solution of ammonium thiosulfate and mercaptan added was 17 mL, and the concentration was 9%.

[0094] (2) The impregnated product was placed in a reactor for drying under the following conditions: temperature 140℃, time 6h; the reactor was then heated further, and hydrogen gas was introduced into the reactor to activate the impregnated product, thereby obtaining a sulfide-state hydrogenation catalyst; the activation conditions were: temperature 320℃, pressure 3.5MPa, volume hourly space velocity 13000h⁻¹. -1 Activation time: 8 hours;

[0095] (3) After activation, a mixture of inert gas and carbon-containing passivating agent is introduced into the reactor to passivate the sulfide-state hydrogenation catalyst. The carbon-containing passivating agent is methane, propylene, and butyne (in a ratio of 50:30:20). The concentration of the carbon-containing passivating agent in the mixture is 12v%. The passivation conditions are: temperature 430℃, pressure 1.5MPa, and volume hourly space velocity 10000h. -1 The time was 8 hours; the reactor was heated at a rate of 30℃ / h.

[0096] After passivation, nitrogen gas is introduced into the reactor. When the temperature drops to 20°C, the passivated sulfurized gasoline hydrodesulfurization catalyst is unloaded and named C7.

[0097] Example 8

[0098] (1) An oxidized gasoline hydrodesulfurization catalyst was impregnated with a mixed solution of ammonium thiosulfate, sulfur and mercaptan in equal volume, wherein the volume of the catalyst was 100 mL, and the amount of ammonium thiosulfate, sulfur and mercaptan solution added was 21 mL with a concentration of 10%.

[0099] (2) The impregnated product was placed in a reactor for drying under the following conditions: temperature 120℃, time 4h; the reactor was then heated further, and hydrogen gas was introduced into the reactor to activate the impregnated product, thereby obtaining a sulfide-state hydrogenation catalyst; the activation conditions were: temperature 300℃, pressure 3.0MPa, volume hourly space velocity 10000h⁻¹. -1 Activation time: 8 hours;

[0100] (3) After activation, a mixture of inert gas and carbon-containing passivating agent is introduced into the reactor to passivate the sulfide-state hydrogenation catalyst. The carbon-containing passivating agent consists of methane, carbon dioxide, ethylene, and acetylene (in a ratio of 40:20:30:10). The concentration of the carbon-containing passivating agent in the mixture is 9v%. The passivation conditions are: temperature 420℃, pressure 3.5MPa, and volume hourly space velocity 6000h. -1 The time was 7 hours; the reactor was heated at a rate of 30℃ / h.

[0101] After passivation, nitrogen gas is introduced into the reactor. When the temperature drops to 20°C, the passivated sulfurized gasoline hydrodesulfurization catalyst is unloaded and named C8.

[0102] Comparative Example 1

[0103] Compared with Example 1, step (3) is replaced with "After activation, nitrogen gas is introduced into the reactor to cool it to 40°C, and then a mixture of inert gas and oxygen is introduced for passivation treatment. The volume percentage concentration of oxygen in the mixture is 1%, and the passivation conditions are: pressure 2.0 MPa, volume hourly space velocity 1000 h⁻¹". -1 The time was 3 hours; after passivation, the hydrogenation catalyst was unloaded. Under the same conditions, the catalyst was named D1.

[0104] Comparative Example 2

[0105] Compared with Comparative Example 1, the following was changed: "After activation, nitrogen gas was introduced into the reactor to cool it down to 40°C, and then a mixture of inert gas and oxygen was introduced for passivation treatment, with the volume percentage concentration of oxygen in the mixture being 1%": "After activation, nitrogen gas was introduced into the reactor to cool it down to 100°C, and then 16g of a mixture of propanolamine and glycerol (mass ratio of the two is 1:2) was added". Other conditions remained unchanged, and the catalyst was named D2.

[0106] Comparative Example 3

[0107] Compared with Example 4, the carbon-containing passivating agent in step (3) was replaced with carbon dioxide, while other conditions remained unchanged. The catalyst was named D3.

[0108] Comparative Example 4

[0109] Compared with Comparative Example 3, the carbon-containing passivating agent in step (3) was replaced with methane, while other conditions remained unchanged. The catalyst was named D4.

[0110] Comparative Example 5

[0111] Compared with Comparative Example 4, the carbon-containing passivating agent in step (3) was replaced with propylene, while other conditions remained unchanged. The catalyst was named D5.

[0112] Comparative Example 6

[0113] Compared with Comparative Example 5, the carbon-containing passivating agent in step (3) was replaced with acetylene, while other conditions remained unchanged. The catalyst was named D6.

[0114] Table 1 Evaluation results of passivation effect and hydrogenation activity

[0115] serial number catalyst Sulfur retention rate / % Carbon deposits / % Hydrodesulfurization rate / % Hydrogen saturation rate / % Example 1 C1 75 1.47 90 50 Example 2 C2 73 1.33 91 51 Example 3 C3 76 1.31 92 47 Example 4 C4 76 1.27 91 52 Example 5 C5 77 1.53 90 45 Example 6 C6 75 1.35 92 51 Example 7 C7 76 1.58 89 42 Example 8 C8 77 1.45 95 47 Comparative Example 1 D1 75 - 83 76 Comparative Example 2 D2 76 - 85 78 Comparative Example 3 D3 76 0.41 87 63 Comparative Example 4 D4 76 1.07 86 55 Comparative Example 5 D5 76 1.52 83 41 Comparative Example 6 D6 76 1.84 80 41

[0116] As shown in Table 1, Examples 1-8 used an impregnation method to introduce sulfur-containing compounds into the pores of the oxidized hydrogenation catalyst, allowing them to combine with the sulfur-containing compounds. After activation with hydrogen, the sulfur loading rate (sulfur retention rate) and hydrogenation activity of the catalyst were guaranteed. Passivation treatment with a specific type of carbon-containing passivating agent ensured the safety of the sulfurized hydrogenation catalyst during storage, transportation, and start-up. Simultaneously, as the hydrogenation process progressed, the increased reaction temperature decomposed the carbon deposits, promoting the release of hydrogenation active sites and ensuring that the activity of the passivated sulfurized hydrogenation catalyst did not decrease, achieving a hydrodesulfurization rate of over 89%.

[0117] The passivation method for hydrogenation catalysts provided by this invention uses a carbon-containing passivating agent to passivate the catalyst surface, thereby coating the active sites and ensuring the safety of the sulfide-state hydrogenation catalyst. It also ensures that the activity of the sulfide-state hydrogenation catalyst is not reduced. In addition, the passivation method for hydrogenation catalysts proposed in this invention is simple, low-cost, and suitable for large-scale industrial applications.

[0118] The preferred embodiments and experimental verifications of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for passivating a hydrogenation catalyst, characterized in that, Includes the following steps: A sulfurized hydrogenation catalyst is passivated using a carbon-containing passivating agent; wherein the carbon-containing passivating agent includes at least two of carbon dioxide, low-carbon alkanes, low-carbon olefins, and low-carbon alkynes; the carbon-containing passivating agent causes carbon deposits to coat the active sites of the sulfurized hydrogenation catalyst, and the carbon deposits decompose under hydrogen and hydrogenation reaction temperature conditions.

2. The passivation method according to claim 1, characterized in that, The low-carbon alkane is selected from C1-C5 alkanes; the low-carbon olefin is selected from C2-C6 olefins; and the low-carbon alkyne is selected from C2-C5 alkynes.

3. The passivation method according to claim 1, characterized in that, The passivation treatment conditions are: temperature 350℃~460℃, pressure 0.5 MPa~3.5 MPa, and volume hourly space velocity 500 h⁻¹. -1 ~10000h -1 The passivation time is 2h~10h.

4. The passivation method according to any one of claims 1-3, characterized in that, The sulfide-state hydrogenation catalyst is brought into contact with a mixture of inert gas and a carbon-containing passivating agent to perform the passivation treatment; in the mixture, the volume concentration of the carbon-containing passivating agent is 1%-10%.

5. The passivation method according to any one of claims 1-3, characterized in that, After passivation, the process also includes cooling the passivated sulfide-state hydrogenation catalyst to 0-50°C under an inert atmosphere.

6. The passivation method according to any one of claims 1-3, characterized in that, The sulfide-state hydrogenation catalyst is prepared by the following steps: the oxidized hydrogenation catalyst is impregnated and sulfided in a solution containing sulfur compounds, and then activated by passing hydrogen gas to obtain the sulfide-state hydrogenation catalyst.

7. The passivation method according to claim 6, characterized in that, The sulfur-containing compound is at least one of ammonium sulfide, ammonium thiosulfate, sulfur, and thiols.

8. The passivation method according to claim 6, characterized in that, After impregnation and vulcanization, the impregnated product is dried under the following conditions: temperature 50℃~150℃, time 2h~6h.

9. The passivation method according to claim 6, characterized in that, The activation conditions were: temperature 200℃~320℃, pressure 1.5MPa~3.5MPa, and volumetric hourly space velocity 6000 h⁻¹. -1 ~13000h -1 The time is 2 hours to 8 hours.

10. The passivation method according to claim 6, characterized in that, The oxidized catalyst includes a support and an active metal supported on the support. The active metal includes at least one metal element from Group VIB and Group VIII of the periodic table. The support includes at least one of alumina, zirconium oxide, silicon oxide, activated carbon, diatomaceous earth, and zeolite.

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