Passivated nickel hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention provides a passivated nickel series hydrogenation catalyst and a preparation method and application thereof, and the passivated nickel series hydrogenation catalyst comprises a reduction state nickel series hydrogenation catalyst, the first passivating agent occupies part of pore channels of the reduction-state nickel-series hydrogenation catalyst, the protective layer is coated on the surface of the reduction-state nickel-series hydrogenation catalyst and is formed by a second passivating agent, the first passivating agent comprises high-melting-point wax, the second passivating agent comprises low-melting-point wax, and the total weight of the reduction-state nickel-series hydrogenation catalyst is 100%. The content of the high-melting-point wax is 0.5-15%, and the content of the low-melting-point wax is 0.1-5%. The mechanical strength of the passivated nickel hydrogenation catalyst is improved through passivating treatment, and the storage, transportation and filling risks of the catalyst are reduced; meanwhile, when the catalyst is started to be used, initial activity slow release can be achieved, and good stability is achieved; and meanwhile, the preparation method has the characteristics of controllable passivation degree, direct feeding start-up, shortened start-up period and the like.

Description

Technical Field

[0001] This invention relates to a passivated nickel-based hydrogenation catalyst, its preparation method, and its application, belonging to the field of refining and chemical technology. Background Technology

[0002] Metal catalysts have a wide range of applications, especially in hydrogenation. Typically, the metal component in the prepared catalyst exists in oxide form, and only after reduction treatment can it acquire catalytic activity. The effectiveness of the reduction directly affects its performance. Currently, metal catalysts mainly fall into two categories: noble metals and non-noble metals. Noble metal catalysts are represented by Pt and Pd as active components. These catalysts have good hydrogenation performance, but they are expensive and have poor resistance to impurities. Non-noble metal catalysts mainly use transition metal Ni as the active component, overcoming the aforementioned problems of noble metal catalysts. However, unlike the lower loading of noble metals, non-noble metal catalysts typically require a metal content of over 30 wt% to achieve the desired hydrogenation performance, which presents a challenge in catalyst preparation. The impregnation method commonly used in catalyst preparation is simple and low-cost, but it is effective for catalysts with low metal content. When the metal content is high, the difficulty in dissolving the precursor makes a one-step impregnation process insufficient, often requiring a multi-step impregnation process to achieve the required loading. This process is cumbersome and can affect the dispersion and utilization rate of the active metal component. Coprecipitation has become a preferred method for preparing high-content, multi-component hydrogenation catalysts, but the preparation process is relatively complex and generates a large amount of wastewater, which does not meet the requirements of green and economical production.

[0003] Nickel-based catalysts require reduction treatment to convert nickel oxide into metallic nickel before use. This results in the presence of some high-energy, unstable metallic nickel species on the catalyst surface after reduction. While these nickel species exhibit good hydrogenation activity, allowing the catalyst to be used directly after feeding into the plant, the initial catalyst activity is too high. The hydrogenation of unsaturated hydrocarbons in the feedstock generates a large amount of heat, potentially causing bed overheating, affecting normal plant operation, or even burning the catalyst, posing a significant risk. Therefore, it is necessary to study appropriate passivation treatment of unstable, high-energy active sites on reduced nickel-based catalysts before their use in industrial plants.

[0004] To date, passivation methods mainly employ two technical routes: Route 1 involves oxidizing the catalyst by adsorbing oxidizing gases, thereby appropriately covering the active sites; Route 2 involves using oil containing unsaturated hydrocarbons or sulfides to passivate the catalyst, inhibiting the initial activity of the catalyst by surface carbonization or causing micro-poisoning of the metal.

[0005] For Route 1, the relevant existing technologies include CN 104226375A, among which CN 104226375A discloses a method for hydrothermal passivation of the initial activity of a nickel-based selective hydrogenation catalyst. The passivation method mainly includes two processes: (1) reduction of the catalyst, in which nickel exists in the catalyst in the form of elemental form after reduction; (2) hydrothermal passivation treatment of the catalyst after reduction, in which the catalyst is loaded into the reactor bed and water vapor at a certain temperature is introduced into it so that the water vapor and the catalyst are in full contact, thereby completing the hydrothermal passivation treatment of the catalyst.

[0006] The pre-reduced-oxidized catalyst obtained through the above route one needs to have its oxide layer on the catalyst surface reduced again at an appropriate temperature before being put into use, which increases the start-up process; and the catalyst still has high initial activity after reduction. If it is fed directly, the reaction will be highly exothermic, which can easily cause the reactor bed to "run away".

[0007] For Route 2, the relevant existing technologies include CN 101822985A and "Research on Passivation Method of Nickel-based Cracking Gasoline First-Stage Hydrogenation Catalyst", etc. Among them, CN 101822985A discloses a pretreatment method for nickel-based hydrogenation catalyst, which mainly consists of two steps: (1) under a reducing atmosphere, the catalyst is reduced in stages in a fixed bed reactor or converter, and the reduction is completed; (2) catalyst passivation: at a hydrogen pressure of 2-3 MPa, a catalyst bed temperature of 20-30℃, and a passivating agent space velocity of 5-20 h⁻¹. -1 Under certain conditions, the passivating agent is brought into contact with the catalyst for 3-5 hours. The passivating agent is an oil containing olefins, with an olefin content of 0.1-40% and a sulfur content of 0-500 mg / kg.

[0008] The paper, "Research on Passivation Method of First-Stage Hydrogenation Catalyst for Nickel-Based Cracked Gasoline," focuses on nickel-based catalysts. It investigates the passivation and start-up processes using straight-run naphtha and first-stage hydrogenation products from different distillation fractions of cracked gasoline (C5-C7, C6-C7, C5-C8, and C5-C9) as passivation feedstocks. The results show that first-stage hydrogenation products from cracked gasoline with low olefin content can replace straight-run naphtha as passivation feedstocks for nickel-based catalysts.

[0009] The passivated catalyst obtained through Route 2 also has some shortcomings. For example, while using sulfides for passivation solves the problem of high initial catalyst activity, sulfides are highly toxic during use, especially polysulfides, which can cause serious environmental pollution due to volatilization. If sulfur is injected into naphtha for passivation, improper control of the injection amount can lead to ineffective or excessive passivation, affecting the catalyst's hydrogenation performance. Furthermore, sulfur injection increases the complexity of the operation. For another example, when naphtha is used as the passivation feedstock, low temperature rise during passivation can affect the start-up cycle and result in unsatisfactory passivation, with the initial catalyst activity remaining high after passivation. Conversely, high temperature leads to rapid carbon buildup on the catalyst, affecting its stability during use.

[0010] In summary, the degree of passivation of hydrogenation catalysts directly affects their initial activity, hydrogenation activity, and stability. For this reason, in recent years, more and more researchers in this field have conducted systematic and in-depth research on the passivation of hydrogenation catalysts, aiming to develop passivation methods for hydrogenation catalysts that meet industrial requirements. Summary of the Invention

[0011] To address the aforementioned shortcomings and deficiencies, the present invention aims to provide a passivated nickel-based hydrogenation catalyst, its preparation method, and its applications. The passivated nickel-based hydrogenation catalyst provided by the present invention exhibits improved mechanical strength through passivation treatment, reducing the risks associated with catalyst storage, transportation, and loading. Simultaneously, it achieves a "slow release" of initial activity during catalyst start-up and demonstrates good stability. Furthermore, its preparation method features controllable passivation degree, direct feed start-up, and a shortened start-up cycle.

[0012] To achieve the above objectives, in one aspect, the present invention provides a passivated nickel-based hydrogenation catalyst, wherein the passivated nickel-based hydrogenation catalyst comprises: a reduced nickel-based hydrogenation catalyst, a first passivating agent occupying part of the pores of the reduced nickel-based hydrogenation catalyst, and a protective layer formed by a second passivating agent coating the surface of the reduced nickel-based hydrogenation catalyst, wherein the first passivating agent comprises a high-melting-point wax, the second passivating agent comprises a low-melting-point wax, and based on 100% of the total weight of the reduced nickel-based hydrogenation catalyst, the contents of the high-melting-point wax and the low-melting-point wax are 0.5-15% and 0.1-5%, respectively, preferably 1.5-8% and 0.5-3%, respectively.

[0013] In one specific embodiment of the passivated nickel-based hydrogenation catalyst described above in this invention, the melting point of the high-melting-point wax is in the range of 100-200°C.

[0014] As a specific embodiment of the passivated nickel-based hydrogenation catalyst described above in this invention, the high-melting-point wax includes one or a combination of several long-chain organic compounds such as polyethylene wax, polypropylene wax, polystyrene wax, and industrial wax, preferably polypropylene wax.

[0015] In one specific embodiment of the passivated nickel-based hydrogenation catalyst described above in this invention, the melting point of the low-melting-point wax is in the range of 30-90°C.

[0016] As a specific embodiment of the passivated nickel-based hydrogenation catalyst described above in this invention, the low-melting-point wax includes one or more of natural wax, paraffin wax, and Fischer-Tropsch wax, preferably paraffin wax.

[0017] In one specific embodiment of the passivated nickel-based hydrogenation catalyst described above, the thickness of the protective layer is 0.1-3 μm, preferably 0.5-1.5 μm. The protective layer should not be too thin, otherwise it will not achieve the desired effect, increasing safety risks during packaging, storage, transportation, and filling. Furthermore, the reduced nickel-based hydrogenation catalyst will re-oxidize upon contact with air, thus affecting catalyst performance. Conversely, the protective layer should not be too thick either, as an excessively thick layer will increase the cost of catalyst passivation treatment, affect the feed replacement time, increase the generation of byproducts such as sludge and oil, and even negatively impact the quality of the hydrogenated product.

[0018] On the other hand, the present invention also provides a passivation treatment method for the nickel-based hydrogenation catalyst described above, wherein the passivation method includes:

[0019] Step (1): After mixing the high melting point wax with the large molecular petroleum hydrocarbon, heat the system to a temperature higher than the melting point of the high melting point wax so that it can be completely melted and thoroughly mixed with the large molecular petroleum hydrocarbon to obtain a liquid first passivating agent with good fluidity.

[0020] Step (2): Under inert atmosphere, the liquid first passivating agent is supported on the reduced nickel-based hydrogenation catalyst and purged with an inert atmosphere until the catalyst surface is slightly dry to obtain the intermediate catalyst.

[0021] Step (3): After mixing the low melting point wax with the small molecule petroleum hydrocarbon, control the system temperature below the melting point of the low melting point wax and make it completely dissolved in the small molecule petroleum hydrocarbon and mix thoroughly to obtain a liquid second passivating agent with good fluidity.

[0022] Step (4): Under an inert atmosphere, the liquid second passivating agent is supported on the intermediate catalyst, and the catalyst surface is purged with an inert atmosphere until it is slightly dry. This forms a protective layer on the surface of the intermediate catalyst, resulting in a passivated nickel-based hydrogenation catalyst.

[0023] As a specific embodiment of the passivation method described above in this invention, the macromolecular petroleum hydrocarbon is a product obtained through refining treatment. In order to achieve the supporting effect, it includes a C13-C20 fraction. The amount added is 0.1-6% based on the total weight of the reduced nickel-based hydrogenation catalyst as 100%, preferably 0.1-5%, more preferably 0.5-4.5%, and even more preferably 0.5-3%.

[0024] In a specific embodiment of the passivation method described above in this invention, in step (2), the loading is impregnation or spraying, preferably impregnation.

[0025] As a specific embodiment of the passivation method described above in this invention, in order to achieve the supporting effect, the small molecule petroleum hydrocarbon includes a product obtained through refining treatment. In order to achieve the supporting effect, it includes C5-C9 fractions, and the amount added is 1-15% based on the total weight of the reduced nickel-based hydrogenation catalyst as 100%, preferably 1.2-8%.

[0026] In a specific embodiment of the passivation method described above in this invention, in step (4), the loading is spraying or impregnation, preferably spraying.

[0027] In steps (2) and (4) of the passivation method described above in this invention, the impregnation includes, for example but not limited to, the following steps: weighing a certain amount of catalyst and testing its saturated water absorption rate, weighing a certain amount of passivating agent according to its water absorption rate, and uniformly impregnating the passivating agent on the catalyst by rotating a drum or a converter under a certain temperature and oxygen-free environment.

[0028] The spraying process includes, for example but not limited to, the following steps: weighing a certain amount of catalyst and testing its saturated water absorption rate; based on its water absorption rate, weighing a certain amount of passivating agent; and spraying the passivating agent onto the catalyst in a mist form under the conditions of a rotating drum or converter at a certain temperature and in an oxygen-free environment, thereby achieving the passivation process.

[0029] In step (4) of the preparation method described above, the term "micro-dry" refers to a state where the catalyst surface is between wet and dry, and the catalyst particles do not stick together or clump together, and their morphology is as complete and independent particles.

[0030] This invention does not particularly limit the specific source of nickel-containing hydrogenation catalysts (oxidized state), i.e., nickel-based hydrogenation catalysts. They can be obtained by existing conventional methods, such as impregnation, co-precipitation, kneading, and spraying (such as the methods disclosed in CN 116173968A, CN109433220A, CN101037613A, or CN103666548A), or they can be obtained commercially.

[0031] For example, the nickel-containing hydrogenation catalyst can be prepared using the method disclosed in CN 116173968A, and is mainly used in the field of petroleum resin hydrogenation after synthesis. The catalyst composition, based on 100 parts by weight, contains 30-70% nickel; therefore, it is prepared using a co-precipitation method, with the specific steps as follows:

[0032] Step 1: Provide a mixed solution and an alkaline salt solution, wherein the mixed solution comprises zinc, magnesium, and nickel;

[0033] Step 2: Use the alkaline salt solution as a precipitant to co-precipitate the mixed solution to obtain a mixed source slurry;

[0034] Step 3: Mix the mixed source slurry and the aluminum source slurry to obtain a mixed slurry. The preparation method of the aluminum source slurry includes: passing a mixed gas containing carbon dioxide into a sodium aluminate aqueous solution in a flowing state to carry out a gelation reaction until a gelation slurry with a pH value of 9.0-10.5 is obtained; subjecting the gelation slurry to a first aging treatment to obtain an aged gelation slurry; and adding a pore-expanding agent to the aged gelation slurry to carry out a pore-expanding treatment to obtain the aluminum source slurry.

[0035] Step 4: The mixed slurry is subjected to a second aging process, filtration and washing, and drying to obtain dried powder;

[0036] Step 5: The excipient is used to shape the dried powder, and the resulting shaped product is dried and calcined in sequence to remove free water and the excipient, so as to obtain the nickel-based hydrogenation catalyst.

[0037] For example, the nickel-containing hydrogenation catalyst can also be prepared using the method disclosed in CN103666548A, and after synthesis, it is mainly used in the selective hydrogenation of cracked gasoline. The catalyst composition, based on 100% by weight, contains 14-19% nickel oxide; therefore, it is prepared using an impregnation method, with the specific steps as follows:

[0038] Step 1): Prepare a solution by mixing the additives, accelerators and water, spray the solution onto the aluminum hydroxide powder, and knead the powder to ensure full contact with the additives. Then, extrude the solution into strips, dry and calcine to obtain an alumina carrier containing the additives.

[0039] Step 2): Dissolve the precursor salt containing the active component nickel and the remaining auxiliary components in water, then add a complexing agent to make an impregnation solution, impregnate the alumina support containing the auxiliary agents, dry and calcine to obtain the catalyst.

[0040] For example, the nickel-containing hydrogenation catalyst (oxidized state) used in this invention may include an active metal oxide, an auxiliary agent, and a support; wherein, based on 100 parts by weight of the total weight of the nickel-containing hydrogenation catalyst (oxidized state), the support is 15-35 parts by weight, the active component nickel oxide is 45-75 parts by weight, and the auxiliary oxide is 1-10 parts by weight.

[0041] Preferably, based on 100 parts by weight of the total weight of the nickel-containing hydrogenation catalyst (oxidized state), the support is 18-25 parts by weight; the active component nickel oxide is 55-70 parts by weight; and the auxiliary oxide is 2-7 parts by weight.

[0042] The nickel-containing hydrogenation catalyst described above in this invention can be prepared by a method including the following specific steps: the preparation of the active component and the extrusion molding of the catalyst. The specific steps are as follows:

[0043] Step (a): Weigh a certain amount of deionized water, and dissolve the precursor of the active component nickel, the auxiliary agent and a 40% nitric acid solution in the above deionized water under stirring. After complete dissolution, slurry I is formed.

[0044] Step (b): Dissolve the precipitant in a certain amount of deionized water to prepare solution II;

[0045] Step (c): Under stirring, add solution II dropwise to slurry I in the reactor to carry out the neutralization reaction. The reaction temperature is controlled at 40-60℃. At the same time, add carrier powder to the reactor and stir continuously until the pH value of the neutralized solution reaches 8-10 and is mixed evenly.

[0046] Step (d): After the neutralization reaction is complete, raise the temperature to 60-90℃ and let it stand for aging for 2-8 hours;

[0047] Step (e): The material obtained in step (d) is filtered, and the resulting filter cake is dried at 80-120℃ for 2-12 hours, calcined at 300-500℃ for 2-6 hours, and ground to obtain a nickel-containing active component material;

[0048] Step (f): Dry mix the nickel-containing active component material obtained in step (e) with the extrusion aid, and then knead it with an aqueous solution containing a binder. After kneading for 20-60 minutes, extrude it into strips, dry and calcine it. The drying and calcine heat treatment conditions can be kept consistent with the heat treatment conditions of the nickel-containing active component material in step (e) to obtain the nickel-containing hydrogenation catalyst.

[0049] In steps (a) and (b) above, the mass ratio of the active component, auxiliary agent, and precipitant to deionized water is 1:2 to 1:5.

[0050] In step (a), the precursor of the active component nickel is a soluble salt, which may be selected from one or more of nitrates, oxalates, sulfates and acetates.

[0051] In step (a), the additive is one or more of Group IIA, Group IB, Group IIB, Group IVB and rare earth metals, preferably one or more of Mg, Cu, Zn, Zr, La and Ce.

[0052] The addition of additives can effectively reduce the electron density around Ni, inhibit nickel aggregation, and improve the catalyst's resistance to sintering and hydrogenation stability.

[0053] In step (a), the precursor of the adjuvant is a soluble salt, which may be selected from one or more of nitrates, oxalates, sulfates, carbonates and acetates.

[0054] In step (b), the precipitant may be selected from one or more of potassium carbonate, potassium hydroxide, ammonium bicarbonate, ammonium carbonate, potassium bicarbonate, and ammonia.

[0055] In step (c), the carrier powder may be selected from one or more of the following: boehmite, amorphous aluminum silicate, silicon dioxide, titanium dioxide, aluminum sol, or silica sol.

[0056] In step (f), the extrusion aid is guar gum powder, and its dosage is 2-10% of the nickel-containing active component, preferably 3-7%. Other conventional extrusion aids are also applicable.

[0057] In step (f), the adhesive solvent is an acid, which can be an organic acid or an inorganic acid, selected from one or more of oxalic acid, citric acid, nitric acid, and hydrochloric acid. The amount of adhesive solvent used is 1-10% of the nickel-containing active component, preferably 1-5%.

[0058] This invention does not particularly limit the reduction process of nickel-containing hydrogenation catalysts, including reduction methods and reduction process conditions. Known processes, such as single-stage reduction and multi-stage reduction, can be used to reduce them, as long as the nickel element in the reduced catalyst, i.e. the reduced nickel-based hydrogenation catalyst, exists in the form of elemental nickel.

[0059] In this invention, the reduction treatment of the nickel-containing hydrogenation catalyst can be carried out using any known process and parameters in the art. For example, the single-stage reduction treatment method and multi-stage reduction treatment method disclosed in CN115254124A can be used. The conditions of the single-stage reduction treatment method include: heating to 100-750°C, preferably 200-650°C, at a heating rate of 50-150°C / hour; a pressure of 0-2.0 MPa, preferably 0.2-1.8 MPa; and holding at that temperature for 0.3-8 hours, preferably 0.5-6 hours. According to one embodiment of the invention, in the single-stage reduction treatment method, the reduction temperature of the catalyst is preferably 350-550°C, and the reduction residence time does not exceed 2 hours, preferably 0.5-1.5 hours.

[0060] The multi-stage reduction process includes gradually increasing the reaction temperature at a heating rate of 60-150℃ / hour and holding the temperature at each stage for a period of time. The reduction temperature of the first stage is 160-300℃, and the reduction temperature of the last stage is 320-520℃. The holding time of each stage is independently selected from 0.3-8 hours, preferably 0.5-6 hours.

[0061] The reduction of the nickel-containing hydrogenation catalyst provided by this invention can be carried out under certain temperature and pressure conditions using hydrogen or hydrogen-containing gas. The specific reduction conditions are as follows:

[0062] Reduction pressure: 0.2-2.0 MPa;

[0063] Volume ratio of reducing gas to catalyst: 500-1300 Nm 3 / m 3 / h;

[0064] The reduction process employs a programmed temperature increase method: the bed temperature is raised to 180-260℃ at a rate of 25-50℃ / h and held at that temperature for 2-6 hours; then the bed temperature is raised to 340-380℃ at a rate of 10-20℃ / h and held at that temperature for 4-10 hours; then the bed temperature is raised to 400-470℃ at a rate of 10-20℃ / h and held at that temperature for 8-12 hours, then cooled to room temperature to complete the reduction and obtain the reduced nickel-based hydrogenation catalyst.

[0065] In one specific embodiment of the preparation method described above in this invention, the inert atmosphere includes nitrogen or helium, etc.

[0066] Furthermore, this invention also provides the application of the passivated nickel-based hydrogenation catalyst described above in the selective hydrogenation reaction of gasoline. By using the passivated nickel-based hydrogenation catalyst described above in the selective hydrogenation reaction of gasoline, this invention can achieve selective hydrogenation of dienes and thiol refining. While protecting the subsequent hydrorefining catalyst to ensure long-term stable operation, it improves the distribution of sulfides in gasoline and enhances the quality of the products from the subsequent hydrogenation reaction.

[0067] Compared with the prior art, the beneficial technical effects achieved by the present invention include:

[0068] The passivated nickel-based hydrogenation catalyst provided by this invention is a product obtained by staged passivation treatment of a reduced nickel-based hydrogenation catalyst under inert gas protection. First, molten high-melting-point wax is fully dissolved in large-molecule petroleum hydrocarbons to obtain a liquid passivating agent with good flowability, which is then supported on the reduced nickel-based hydrogenation catalyst to ensure it occupies part of the catalyst's pores and solidifies within the catalyst's internal pores during subsequent cooling (i.e., a purging process using an inert atmosphere). Second, low-melting-point wax is dissolved in small-molecule petroleum hydrocarbons to obtain a liquid passivating agent with good flowability, which is then supported on the reduced nickel-based hydrogenation catalyst to form a dense protective layer on the catalyst surface.

[0069] Therefore, this invention uses different passivating agents to perform segmented passivation treatment on the catalyst, "targeting" and covering the active sites at different locations on the catalyst. The passivating agent, i.e., the protective layer, which wraps around the catalyst, not only prevents the surface active sites from oxidizing upon contact with air, reducing their storage and transportation risks, but also allows for direct feeding during the start-up of the unit, shortening the start-up cycle. Furthermore, it effectively improves the mechanical strength of the catalyst. Moreover, this protective layer is mainly composed of small molecule petroleum hydrocarbons and low-melting-point waxes, which can be quickly flushed out after oil feeding without affecting product performance.

[0070] The passivating agent solidified within the pores of the catalyst can also improve its mechanical strength to some extent. However, more importantly, it is relatively stable in the low-temperature reaction range during the initial startup phase, covering some of the active sites within the pores. This effectively suppresses initial startup activity, preventing the risk of catalyst bed overheating due to excessively high initial activity and ensuring a smooth startup process. Subsequently, as the reaction temperature gradually increases, this activity can be released through hydrogenolysis or melting, thereby improving the catalyst's stability.

[0071] In summary, the passivated nickel-based hydrogenation catalyst provided by this invention solves the problems of existing technologies for passivating nickel-containing catalysts, especially high-nickel catalysts, where the passivation degree is difficult to control, resulting in either insufficient passivation or over-passivation, which in turn affects the hydrogenation activity and stability of the catalyst in subsequent use. Furthermore, it also solves a series of problems inherent in existing passivation technologies, such as the need for catalyst reactivation before use, cumbersome and time-consuming processes, and the high toxicity of sulfides during use, particularly the serious environmental pollution caused by the volatilization of polysulfides. Attached Figure Description

[0072] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0073] Figure 1 This is a microscopic image of the passivated nickel-based hydrogenation catalyst provided in Example 1 of the present invention. Detailed Implementation

[0074] It should be noted that the term "comprising" and any variations thereof in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0075] The "range" disclosed in this invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0076] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this invention, and "0-5" is simply a shortened representation of these numerical combinations.

[0077] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in this invention can be combined with each other to form new technical solutions.

[0078] In this invention, unless otherwise specified, all technical features and preferred features mentioned in this invention can be combined with each other to form new technical solutions.

[0079] In this invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0080] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying tables, drawings, and embodiments. The embodiments described below are some, but not all, embodiments of this invention, and are only used to illustrate the invention, and should not be considered as limiting the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0081] Preparation Example 1

[0082] This preparation example provides a reduced nickel-based hydrogenation catalyst, which is obtained by a preparation method including the following specific steps:

[0083] Using H2 as the reducing gas, a nickel-based hydrogenation catalyst (based on a total weight of 100 parts by weight of the nickel-based hydrogenation catalyst in this oxidized state, including 23.6 parts by weight of the support mixture of silica and alumina, 71.2 parts by weight of the active metal oxide nickel oxide, 0.8 parts by weight of the auxiliary agent magnesium oxide, 2.9 parts by weight of the auxiliary agent copper oxide, and 1.5 parts by weight of the auxiliary agent zirconium oxide) was placed in a reduction reactor;

[0084] Under hydrogen-rich conditions, the bed temperature was initially increased from 25°C to 220°C at a rate of 45°C / h and held for 2 hours. Then, the bed temperature was increased to 350°C at a rate of 15°C / h and held for 4 hours. Finally, the bed temperature was increased to 420°C at a rate of 10°C / h and held for 10 hours, before being cooled to room temperature. During the reduction process, the pressure was 0.5 MPa, and the volume ratio of H2 to catalyst was 750 Nm³. 3 / m 3 / h, the reduction ends, and the reduced nickel-based hydrogenation catalyst is obtained, denoted as Cat-1.

[0085] Example 1

[0086] This embodiment involves passivating Cat-1, providing a method for preparing a passivated nickel-based hydrogenation catalyst, including:

[0087] Step (1): Add polypropylene wax and C13-C16 straight-chain alkanes to a first sealed container, raise the temperature of the first sealed container to 135°C to completely melt the polypropylene wax, and mix it thoroughly with the C13-C16 straight-chain alkanes under stirring to obtain a stable liquid first passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of polypropylene wax and C13-C16 straight-chain alkanes are 3.5% and 2.8%, respectively;

[0088] Step (2): Under nitrogen atmosphere, the liquid first passivating agent is supported on Cat-1 by impregnation, and then a certain amount of nitrogen is introduced for purging until the catalyst surface is slightly dry to obtain the intermediate catalyst.

[0089] Step (3): Paraffin wax and C5-C7 straight-chain alkanes are added to the second sealed container. The temperature of the first sealed container is controlled at 60°C. Paraffin wax is completely dissolved in C5-C7 straight-chain alkanes under stirring to obtain a stable liquid second passivating agent. The amounts of low-melting-point wax and small-molecule petroleum hydrocarbons are 1.9% and 6.8% respectively, based on the total weight of Cat-1 as 100%.

[0090] Step (4): Under helium atmosphere, the liquid second passivating agent is carried on the intermediate catalyst by spraying. After the treatment is completed, a certain amount of helium is introduced to purge the catalyst until the catalyst surface is slightly dry, that is, the passivation is completed, and the passivated nickel-based hydrogenation catalyst is obtained, which is denoted as P1.

[0091] The passivated nickel-based hydrogenation catalyst includes a reduced nickel-based hydrogenation catalyst, namely Cat-1, a first passivating agent occupying part of the pores of the reduced nickel-based hydrogenation catalyst, and a protective layer formed by a second passivating agent coating the surface of the reduced nickel-based hydrogenation catalyst. The first passivating agent contains polypropylene wax, and the second passivating agent contains paraffin wax. Based on 100% of the total weight of the reduced nickel-based hydrogenation catalyst, the contents of polypropylene wax and paraffin wax are 3.5% and 1.9%, respectively, and the thickness of the protective layer is 1 μm.

[0092] Example 2

[0093] This embodiment involves passivating Cat-1, providing a method for preparing a passivated nickel-based hydrogenation catalyst, including:

[0094] Step (1): Add polypropylene wax and C14-C18 straight-chain alkanes to a first sealed container, raise the temperature of the first sealed container to 160°C to completely melt the polypropylene wax, and mix it thoroughly with the C14-C18 straight-chain alkanes under stirring to obtain a stable liquid first passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of polypropylene wax and C14-C18 straight-chain alkanes are 6.1% and 2.2%, respectively;

[0095] Step (2): Under helium atmosphere, the liquid first passivating agent is supported on Cat-1 by impregnation, and then a certain amount of helium is introduced for purging until the catalyst surface is slightly dry to obtain the intermediate catalyst.

[0096] Step (3): Add paraffin and C6-C8 straight-chain alkanes to the second sealed container, control the temperature of the first sealed container at 55°C, and stir to completely dissolve the paraffin in the C6-C8 straight-chain alkanes to obtain a stable liquid second passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of paraffin and C6-C8 straight-chain alkanes are 2.6% and 4.2%, respectively;

[0097] Step (4): Under nitrogen atmosphere, the liquid second passivating agent is carried on the intermediate catalyst by spraying. After the treatment is completed, a certain amount of nitrogen is introduced to purge the catalyst until the catalyst surface is slightly dry, that is, the passivation is completed, and the passivated nickel-based hydrogenation catalyst is obtained, which is denoted as P2.

[0098] The passivated nickel-based hydrogenation catalyst includes a reduced nickel-based hydrogenation catalyst, namely Cat-1, a first passivating agent occupying part of the pores of the reduced nickel-based hydrogenation catalyst, and a protective layer formed by a second passivating agent coating the surface of the reduced nickel-based hydrogenation catalyst. The first passivating agent contains polypropylene wax, and the second passivating agent contains paraffin wax. Based on 100% of the total weight of the reduced nickel-based hydrogenation catalyst, the contents of polypropylene wax and paraffin wax are 6.1% and 2.6%, respectively, and the thickness of the protective layer is 1.4 μm.

[0099] Example 3

[0100] This embodiment involves passivating Cat-1, providing a method for preparing a passivated nickel-based hydrogenation catalyst, including:

[0101] Step (1): Add polyethylene wax and C15-C20 straight-chain alkanes to a first sealed container, raise the temperature of the first sealed container to 102°C to completely melt the polyethylene wax, and mix it thoroughly with the C15-C20 straight-chain alkanes under stirring to obtain a stable liquid first passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of polyethylene wax and C15-C20 straight-chain alkanes are 13.8% and 5%, respectively;

[0102] Step (2): Under nitrogen atmosphere, the liquid first passivating agent is supported on Cat-1 by impregnation, and then a certain amount of nitrogen is introduced for purging until the catalyst surface is slightly dry to obtain the intermediate catalyst.

[0103] Step (3): Add Fischer-Tropsch wax and C6-C8 straight-chain alkanes to the second sealed container, control the temperature of the first sealed container at 46°C, and stir to completely dissolve Fischer-Tropsch wax in the C6-C8 straight-chain alkanes to obtain a stable liquid second passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of Fischer-Tropsch wax and C6-C8 straight-chain alkanes are 4.1% and 12.5%, respectively;

[0104] Step (4): Under helium atmosphere, the liquid second passivating agent is supported on the intermediate catalyst by impregnation. After the treatment is completed, a certain amount of helium is introduced to purge the catalyst until the catalyst surface is slightly dry, that is, the passivation is completed, and the passivated nickel-based hydrogenation catalyst is obtained, which is denoted as P3.

[0105] The passivated nickel-based hydrogenation catalyst includes a reduced nickel-based hydrogenation catalyst, namely Cat-1, a first passivating agent occupying part of the pores of the reduced nickel-based hydrogenation catalyst, and a protective layer formed by a second passivating agent coating the surface of the reduced nickel-based hydrogenation catalyst. The first passivating agent contains polyethylene wax, and the second passivating agent contains Fischer-Tropsch wax. Based on 100% of the total weight of the reduced nickel-based hydrogenation catalyst, the contents of polyethylene wax and Fischer-Tropsch wax are 13.8% and 4.1%, respectively, and the thickness of the protective layer is 2.7 μm.

[0106] Example 4

[0107] This embodiment involves passivating Cat-1, providing a method for preparing a passivated nickel-based hydrogenation catalyst, including:

[0108] Step (1): Add polystyrene wax and C13-C16 straight-chain alkanes into a first sealed container, raise the temperature of the first sealed container to 145°C to completely melt the polystyrene wax, and mix it thoroughly with the C13-C16 straight-chain alkanes under stirring to obtain a stable liquid first passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of polystyrene wax and C13-C16 straight-chain alkanes are 0.6% and 0.4%, respectively;

[0109] Step (2): Under helium atmosphere, the liquid first passivating agent is loaded onto Cat-1 by spraying, and then a certain amount of helium is introduced for purging until the catalyst surface is slightly dry to obtain the intermediate catalyst.

[0110] Step (3): Add Fischer-Tropsch wax and C5-C7 straight-chain alkanes to a second sealed container, control the temperature of the first sealed container at 62°C, and stir to completely dissolve Fischer-Tropsch wax in C5-C7 straight-chain alkanes to obtain a stable liquid second passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of Fischer-Tropsch wax and C5-C7 straight-chain alkanes are 0.8% and 1.1%, respectively;

[0111] Step (4): Under nitrogen atmosphere, the liquid second passivating agent is supported on the intermediate catalyst by impregnation. After the treatment is completed, a certain amount of nitrogen is introduced to purge the catalyst until the catalyst surface is slightly dry, that is, the passivation is completed, and the passivated nickel-based hydrogenation catalyst is obtained, which is denoted as P4.

[0112] The passivated nickel-based hydrogenation catalyst includes a reduced nickel-based hydrogenation catalyst, namely Cat-1, a first passivating agent occupying part of the pores of the reduced nickel-based hydrogenation catalyst, and a protective layer formed by a second passivating agent coating the surface of the reduced nickel-based hydrogenation catalyst. The first passivating agent contains polystyrene wax, and the second passivating agent contains Fischer-Tropsch wax. Based on 100% of the total weight of the reduced nickel-based hydrogenation catalyst, the contents of polystyrene wax and Fischer-Tropsch wax are 0.6% and 0.8%, respectively, and the thickness of the protective layer is 0.6 μm.

[0113] Example 5

[0114] This embodiment involves passivating Cat-1, providing a method for preparing a passivated nickel-based hydrogenation catalyst, including:

[0115] Step (1): Add polystyrene wax and C14-C18 straight-chain alkanes into a first sealed container, raise the temperature of the first sealed container to 158°C to completely melt the polystyrene wax, and mix it thoroughly with the C14-C18 straight-chain alkanes under stirring to obtain a stable liquid first passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of polystyrene wax and C14-C18 straight-chain alkanes are 9.2% and 4.6%, respectively;

[0116] Step (2): Under helium atmosphere, the liquid first passivating agent is loaded onto Cat-1 by spraying, and then a certain amount of helium is introduced for purging until the catalyst surface is slightly dry to obtain the intermediate catalyst.

[0117] Step (3): Add the fruit wax and C5-C7 straight-chain alkanes into the second sealed container, control the temperature of the first sealed container at 66°C, and stir to completely dissolve the fruit wax in the C5-C7 straight-chain alkanes to obtain a stable liquid second passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of fruit wax and C5-C7 straight-chain alkanes are 3.4% and 9.7%, respectively;

[0118] Step (4): Under nitrogen atmosphere, the liquid second passivating agent is supported on the intermediate catalyst by impregnation. After the treatment is completed, a certain amount of the agent is introduced to purge the catalyst until the catalyst surface is slightly dry, that is, the passivation is completed, and the passivated nickel-based hydrogenation catalyst is obtained, which is denoted as P5.

[0119] The passivated nickel-based hydrogenation catalyst includes a reduced nickel-based hydrogenation catalyst, namely Cat-1, a first passivating agent occupying part of the pores of the reduced nickel-based hydrogenation catalyst, and a protective layer formed by a second passivating agent coating the surface of the reduced nickel-based hydrogenation catalyst. The first passivating agent contains polystyrene wax, and the second passivating agent contains fruit wax. Based on 100% of the total weight of the reduced nickel-based hydrogenation catalyst, the contents of polystyrene wax and fruit wax are 9.2% and 3.4%, respectively, and the thickness of the protective layer is 2.1 μm.

[0120] Comparative Example 1

[0121] This comparative example provides a method for passivating Cat-1, i.e., preparing a passivated nickel-based hydrogenation catalyst. The difference between this method and Example 3 is that this comparative example only uses a liquid first passivating agent to passivate Cat-1, including:

[0122] Step (1): Add polyethylene wax and C15-C20 straight-chain alkanes to a first sealed container, raise the temperature of the first sealed container to 102°C to completely melt the polyethylene wax, and mix it thoroughly with the C15-C20 straight-chain alkanes under stirring to obtain a stable liquid first passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of polyethylene wax and C15-C20 straight-chain alkanes are 13.8% and 5%, respectively;

[0123] Step (2): Under nitrogen atmosphere, the liquid first passivating agent is impregnated onto Cat-1, and then a certain amount of nitrogen is introduced for purging until the catalyst surface is slightly dry, that is, the passivation is completed, and the passivated nickel-based hydrogenation catalyst is obtained, denoted as DP1.

[0124] The passivated nickel-based hydrogenation catalyst includes a reduced nickel-based hydrogenation catalyst, namely Cat-1, and a first passivating agent occupying part of the pores of the reduced nickel-based hydrogenation catalyst. The first passivating agent contains polyethylene wax, and the content of polyethylene wax is 13.8% based on 100% of the total weight of the reduced nickel-based hydrogenation catalyst.

[0125] Comparative Example 2

[0126] This comparative example provides a method for passivating Cat-1, i.e., preparing a passivated nickel-based hydrogenation catalyst. The difference between this method and Example 3 is that this comparative example only uses a liquid second passivating agent to passivate Cat-1, including:

[0127] Step (1): Add Fischer-Tropsch wax and C6-C8 straight-chain alkanes to a second sealed container, control the temperature of the first sealed container at 46°C, and stir to completely dissolve Fischer-Tropsch wax in C6-C8 straight-chain alkanes to obtain a stable liquid second passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of Fischer-Tropsch wax and C6-C8 straight-chain alkanes are 4.1% and 12.5%, respectively;

[0128] Step (2): Under helium atmosphere, the liquid second passivating agent is supported on Cat-1 by impregnation. During the support process, a small amount of Fischer-Tropsch wax will enter the catalyst channel along with C6-C8 straight-chain alkanes. However, due to the large molecular weight of Fischer-Tropsch wax and its poor fluidity, most of the Fischer-Tropsch wax will remain on the catalyst surface to form a protective layer. After the treatment, a certain amount of helium is introduced to purge the catalyst until the catalyst surface is slightly dry, that is, the passivation is completed, and the passivated nickel-based hydrogenation catalyst is obtained, which is denoted as DP2.

[0129] The passivated nickel-based hydrogenation catalyst includes a reduced nickel-based hydrogenation catalyst, namely Cat-1, and a protective layer formed by a second passivating agent coating the surface of the reduced nickel-based hydrogenation catalyst. The second passivating agent contains Fischer-Tropsch wax, and the content of Fischer-Tropsch wax is 4.1% based on 100% of the total weight of the reduced nickel-based hydrogenation catalyst. The thickness of the protective layer is 2.7 μm.

[0130] Comparative Example 3

[0131] This comparative example provides a method for preparing a passivated nickel-based hydrogenation catalyst by passivating Cat-1. The only difference between this method and Example 3 is the amount of high-melting-point wax used. The amount of high-melting-point wax used in this comparative example is not within the scope of protection claimed in this application, including:

[0132] Step (1): Add polyethylene wax and C15-C20 straight-chain alkanes to a first sealed container, raise the temperature of the first sealed container to 102°C to completely melt the polyethylene wax, and mix it thoroughly with the C15-C20 straight-chain alkanes under stirring to obtain a stable liquid first passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of polyethylene wax and C15-C20 straight-chain alkanes are 18.6% and 5%, respectively;

[0133] Step (2): Under nitrogen atmosphere, the liquid first passivating agent is supported on Cat-1 by impregnation, and then a certain amount of nitrogen is introduced for purging until the catalyst surface is slightly dry to obtain the intermediate catalyst.

[0134] Step (3): Add Fischer-Tropsch wax and C6-C8 straight-chain alkanes to the second sealed container, control the temperature of the first sealed container at 46°C, and stir to completely dissolve Fischer-Tropsch wax in the C6-C8 straight-chain alkanes to obtain a stable liquid second passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of Fischer-Tropsch wax and C6-C8 straight-chain alkanes are 4.1% and 12.5%, respectively;

[0135] Step (4): Under helium atmosphere, the liquid second passivating agent is supported on the intermediate catalyst by impregnation. After the treatment is completed, a certain amount of helium is introduced to purge the catalyst until the catalyst surface is slightly dry, that is, the passivation is completed, and the passivated nickel-based hydrogenation catalyst is obtained, which is denoted as DP3.

[0136] The passivated nickel-based hydrogenation catalyst includes a reduced nickel-based hydrogenation catalyst, namely Cat-1, a first passivating agent occupying part of the pores of the reduced nickel-based hydrogenation catalyst, and a protective layer formed by a second passivating agent coating the surface of the reduced nickel-based hydrogenation catalyst. The first passivating agent contains polyethylene wax, and the second passivating agent contains Fischer-Tropsch wax. Based on 100% of the total weight of the reduced nickel-based hydrogenation catalyst, the contents of polyethylene wax and Fischer-Tropsch wax are 18.6% and 4.1%, respectively, and the thickness of the protective layer is 2.7 μm.

[0137] Comparative Example 4

[0138] This comparative example provides a method for preparing a passivated nickel-based hydrogenation catalyst by passivating Cat-1. The only difference between this method and Example 3 is the amount of low-melting-point wax used. The amount of low-melting-point wax used in this comparative example is not within the scope of protection claimed in this application, including:

[0139] Step (1): Add polyethylene wax and C15-C20 straight-chain alkanes to a first sealed container, raise the temperature of the first sealed container to 102°C to completely melt the polyethylene wax, and mix it thoroughly with the C15-C20 straight-chain alkanes under stirring to obtain a stable liquid first passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of polyethylene wax and C15-C20 straight-chain alkanes are 13.8% and 5%, respectively;

[0140] Step (2): Under nitrogen atmosphere, the liquid first passivating agent is supported on Cat-1 by impregnation, and then a certain amount of nitrogen is introduced for purging until the catalyst surface is slightly dry to obtain the intermediate catalyst.

[0141] Step (3): Add Fischer-Tropsch wax and C6-C8 straight-chain alkanes to the second sealed container, control the temperature of the first sealed container at 46°C, and stir to completely dissolve Fischer-Tropsch wax in the C6-C8 straight-chain alkanes to obtain a stable liquid second passivating agent; wherein, based on the total weight of Cat-1 as 100%, the amounts of Fischer-Tropsch wax and C6-C8 straight-chain alkanes are 7.5% and 12.5%, respectively;

[0142] Step (4): Under helium atmosphere, the liquid second passivating agent is supported on the intermediate catalyst by impregnation. After the treatment is completed, a certain amount of helium is introduced to purge the catalyst until the catalyst surface is slightly dry, that is, the passivation is completed, and the passivated nickel-based hydrogenation catalyst is obtained, which is denoted as DP4.

[0143] The passivated nickel-based hydrogenation catalyst includes a reduced nickel-based hydrogenation catalyst, namely Cat-1, a first passivating agent occupying part of the pores of the reduced nickel-based hydrogenation catalyst, and a protective layer formed by a second passivating agent coating the surface of the reduced nickel-based hydrogenation catalyst. The first passivating agent contains polyethylene wax, and the second passivating agent contains Fischer-Tropsch wax. Based on 100% of the total weight of the reduced nickel-based hydrogenation catalyst, the contents of polyethylene wax and Fischer-Tropsch wax are 13.8% and 7.5%, respectively, and the thickness of the protective layer is 6.2 μm.

[0144] Test Example 1

[0145] In this test example, a Caikang Optics DMM-900C microscope was used to photograph P1 provided in Example 1 of this invention. The resulting microscope image is shown below. Figure 1 As shown. From Figure 1 As can be seen, the passivation method provided by this invention can indeed form a protective layer on the surface of the reduced nickel-based hydrogenation catalyst, thereby effectively protecting the reduced nickel-based hydrogenation catalyst. Moreover, the degree of passivation is controllable, reducing the storage and transportation risks of the catalyst, and the catalyst does not need to be reactivated before use.

[0146] Test Example 2

[0147] This test example tested the surface autothermal temperatures of P1-P5, DP1-DP4, and the aforementioned unpassivated nickel-containing hydrogenation catalyst Cat-1, including:

[0148] P1-P5, DP1-DP4, and Cat-1 were completely exposed to the same ambient air environment. The surface autothermal temperature of each catalyst was measured using an infrared thermometer during the period from the start of contact with air to 45 minutes (referring to the actual surface temperature of the catalyst after contact with air). The highest surface autothermal temperature of each catalyst is shown in Table 1 below.

[0149] Table 1

[0150] Test object Maximum self-heating temperature of catalyst surface, ℃ Start time, h P1 25.8 4 P2 25.4 5.5 P3 28.3 7 P4 39.6 4 P5 30.2 6.5 DP1 56.7 - DP2 27.4 7.5 DP3 26.1 12 DP4 25.9 14.5 Cat-1 143.5 -

[0151] As shown in Table 1, the segmented passivation method provided in this embodiment of the invention can effectively prevent the oxidation of active sites on the catalyst surface upon contact with air, thereby eliminating the concentrated release of heat from the catalyst. Compared with Cat-1, the nickel-containing hydrogenation catalysts P1 and P2 show almost no heat release upon contact with air, thus significantly reducing the storage, transportation, and use risks of this type of catalyst. Cat-1 and DP1, however, were not passivated or were not sufficiently passivated, resulting in a certain degree of heat release upon contact with air, raising the self-heating temperature of the catalyst surface and affecting subsequent use. Both of these catalysts require reactivation at a certain temperature before startup, thus increasing the startup process and extending the startup time.

[0152] Test Example 3

[0153] In this test example, the strength of P1-P5, DP1-DP4 and the above-mentioned unpassivated nickel-containing hydrogenation catalyst Cat-1 were tested using a VCS strength tester from VINCI, France. The test results are shown in Table 2 below.

[0154] Table 2

[0155] Test object Strength, N / cm P1 55 P2 63 P3 79 P4 47 P5 70 DP1 72 DP2 81 DP3 90 DP4 76 Cat-1 44

[0156] As shown in Table 2, compared with P1-P5 and DP1-DP4, the strength of Cat-1 catalyst was improved to varying degrees after the introduction of the passivating agent. At the same time, it also reduced powdering caused by particle wear during catalyst loading, thus preventing the loss of active catalyst components.

[0157] Test Example 4

[0158] This test example utilizes P1-P5, DP1-DP4, and the aforementioned unpassivated nickel-containing hydrogenation catalyst Cat-1 to conduct selective hydrogenation experiments on catalytic gasoline, in order to examine the catalytic performance of each catalyst. The experiment includes the following steps:

[0159] The above catalysts were separately loaded into 30 mL fixed-bed isothermal reactors. The fixed-bed isothermal reactors were subjected to N2 and H2 pressure and airtightness tests sequentially. After passing the tests, catalytic gasoline and H2 were introduced. The fixed-bed isothermal reactors were then heated at a rate controlled at 5-15 °C / h until the reaction operating conditions were reached: inlet temperature 95 °C, pressure 0.5 MPa, and volumetric hourly space velocity 2.0 h⁻¹. -1With a hydrogen-to-oil volume ratio of 5:1, the reaction system was stabilized under the above conditions. The performance of the hydrogenated product oil after 300 hours of catalytic reaction using catalysts P1-P5, DP1-DP4, and Cat-1 was measured, including the product mercaptan removal rate, diene conversion rate, and loss of research octane number (RON). The results are shown in Table 3.

[0160] The catalytic gasoline is Guangxi Petrochemical's full-fraction catalytic gasoline, with a mercaptan content of 19.6 mg / kg, an olefin content of 33.81 vol%, a diene content of 0.97 gI / 100g, and a research octane number (RON) of 92.4.

[0161] The product thiol removal rate, diene conversion rate, and RON loss are calculated using the following formulas:

[0162]

[0163] RON loss = RON of reactants - RON of products

[0164] Analytical methods for reactants and products include:

[0165] In this embodiment, the thiol content of the oil was analyzed using a 916Ti-Touch potentiometric titrator. Diene values ​​were analyzed according to UOP 326-2008. The oil composition was analyzed using an Agilent 7890B gas chromatograph, and data processing was performed using an HW-2000PONA analytical chromatography workstation. The RON of the oil was tested using an octane number analyzer.

[0166] Table 3

[0167] Test object Thiol removal rate / % Diene conversion rate / % RON loss P1 87.89 71.21 -0.3 P2 86.02 71.44 -0.1 P3 83.05 68.05 0 P4 84.54 69.32 -0.3 P5 82.17 66.02 -0.1 DP1 80.85 61.72 0.2 DP2 81.63 62.91 0.1 DP3 78.26 60.08 0.1 DP4 77.52 59.17 0.3 Cat-1 84.19 67.59 0.2

[0168] Note: In Table 3, the data on thiol removal rate, diene conversion rate and RON loss of DP1 and Cat-1 were obtained after reactivating them at a certain temperature.

[0169] As shown in Table 3, the catalyst passivation method provided in this embodiment can effectively regulate the initial activity of the nickel-containing hydrogenation catalyst after startup and improve its long-term operational stability, enabling the catalyst to have good small molecule thiol re-refining ability and diene hydrogenation selectivity, and reducing RON loss.

[0170] This test example also conducted long-term stability evaluation tests on P1 and Cat-1 respectively. The test results showed that after 1000 hours of stable operation, the mercaptan removal rate, diene conversion rate, and RON loss of P1 were 86.51%, 70.19%, and -0.3 units, respectively; while the mercaptan removal rate, diene conversion rate, and RON loss of Cat-1 were 75.93%, 58.22%, and 0.2 units, respectively. This indicates that the segmented passivation treatment method provided in this embodiment of the invention can delay the deactivation rate of the catalyst and ensure good catalyst stability.

[0171] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical inventions, and technical inventions in this invention can be freely combined and used.

Claims

1. A passivated nickel-based hydrogenation catalyst, characterized in that, The passivated nickel-based hydrogenation catalyst includes a reduced nickel-based hydrogenation catalyst, a first passivating agent occupying part of the pores of the reduced nickel-based hydrogenation catalyst, and a protective layer formed by a second passivating agent coating the surface of the reduced nickel-based hydrogenation catalyst. The first passivating agent contains a high-melting-point wax, and the second passivating agent contains a low-melting-point wax. Based on 100% of the total weight of the reduced nickel-based hydrogenation catalyst, the contents of the high-melting-point wax and the low-melting-point wax are 0.5-15% and 0.1-5%, respectively.

2. The passivated nickel-based hydrogenation catalyst according to claim 1, characterized in that, The melting point of the high-melting-point wax is in the range of 100-200℃.

3. The passivated nickel-based hydrogenation catalyst according to claim 1 or 2, characterized in that, The high melting point wax includes one or a combination of polyethylene wax, polypropylene wax, polystyrene wax, and industrial waxes.

4. The passivated nickel-based hydrogenation catalyst according to claim 1, characterized in that, The melting point of the low-melting-point wax is in the range of 30-90℃.

5. The passivated nickel-based hydrogenation catalyst according to claim 1 or 4, characterized in that, The low-melting-point wax includes one or a combination of natural wax, paraffin wax, and Fischer-Tropsch wax.

6. The passivated nickel-based hydrogenation catalyst according to claim 1, characterized in that, The thickness of the protective layer is 0.1-3 μm.

7. The method for preparing the passivated nickel-based hydrogenation catalyst according to any one of claims 1-6, characterized in that, The preparation method includes: Step (1): After mixing the high melting point wax with the large molecular petroleum hydrocarbon, heat the system to a temperature higher than the melting point of the high melting point wax so that it can be completely melted and thoroughly mixed with the large molecular petroleum hydrocarbon to obtain the liquid first passivating agent. Step (2): Under inert atmosphere, the liquid first passivating agent is supported on the reduced nickel-based hydrogenation catalyst and purged with an inert atmosphere until the catalyst surface is slightly dry to obtain the intermediate catalyst. Step (3): After mixing the low melting point wax with the small molecule petroleum hydrocarbon, control the system temperature below the melting point of the low melting point wax and make it completely dissolve in the small molecule petroleum hydrocarbon to obtain a liquid second passivating agent. Step (4): Under inert atmosphere, the liquid second passivating agent is supported on the intermediate catalyst and purged with an inert atmosphere until the catalyst surface is slightly dry to obtain the passivated nickel-based hydrogenation catalyst.

8. The preparation method according to claim 7, characterized in that, The macromolecular petroleum hydrocarbons include C13-C20 fractions, and the amount added is 0.1-6% based on the total weight of the reduced nickel-based hydrogenation catalyst (100%).

9. The preparation method according to claim 7 or 8, characterized in that, In step (2), the loading is immersion or spraying.

10. The preparation method according to claim 7, characterized in that, The small molecule petroleum hydrocarbons include C5-C9 fractions, and the amount added is 1-15% based on the total weight of the reduced nickel-based hydrogenation catalyst (100%).

11. The preparation method according to claim 7 or 10, characterized in that, In step (4), the load is sprayed or impregnated.

12. The preparation method according to any one of claims 7-8, 10, characterized in that, The inert atmosphere includes nitrogen or helium.

13. The application of the passivated nickel-based hydrogenation catalyst according to any one of claims 1-6 in the selective hydrogenation reaction of catalytic gasoline.

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