Passivation method for sulfurized hydrogenation catalyst and use thereof

Abstract

The present invention relates to the technical field of petrochemical industry. Disclosed are a passivation treatment method for a sulfurized hydrogenation catalyst and the use thereof. The passivation method comprises: loading a passivating agent on a sulfurized hydrogenation catalyst to obtain a passivation catalyst, wherein the passivating agent comprises a solute and a solvent, where the solute is a wax, and the solvent is a light petroleum product. The passivation method for a sulfurized hydrogenation catalyst provided by the present invention has an excellent passivation effect on various sulfurized hydrogenation catalysts, and in particular, can enable the good passivation of a fully sulfurized hydrogenation catalyst having a high degree of affinity to oxygen, thereby significantly improving the use safety thereof, improving the initial hydrogenation activity and selectivity at start-up, avoiding the "thermal runaway" of a reaction bed, and achieving a controllable passivation effect by adjusting the percentage of solute in a passivating agent and the loading amount of the passivating agent on the catalyst.

Description

Passivation methods and applications of sulfide-state hydrogenation catalysts

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Chinese Patent Application No. 202410801164.8, filed on June 20, 2024, entitled “Passivation Method and Application of Sulfated Hydrogenation Catalyst”, the contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of petrochemical technology, specifically to a passivation method and application of a sulfide-state hydrogenation catalyst. Background Technology

[0004] Conventional hydrogenation catalysts are in an oxidized state, while the substances that actually exert their activity in practical applications are in a sulfidated state. Therefore, the catalyst must be sulfided before use. Common sulfidation methods include in-reactor sulfidation and external sulfidation. External sulfidation technology can be further divided into sulfur-supported pre-sulfidation technology and full sulfidation technology, depending on the state of the metal present. Since hydrogenation catalysts treated by external sulfidation technology can be directly used after being added to the reactor, it has the advantages of simple operation, short start-up cycle, and high cost-effectiveness while ensuring the hydrogenation performance of the catalyst. In recent years, it has gradually become the mainstream sulfidation technology and is also the direction of future development.

[0005] After external sulfidation treatment, the hydrogenation catalyst transforms from an oxidized state to a sulfidated state, exhibiting high oxygen affinity. This makes it highly unstable upon contact with oxygen-containing gases (such as air), reacting with oxygen to produce SO2 and heat. When this heat is released in a concentrated manner, spontaneous combustion can occur, affecting catalyst activity and posing a risk of catalyst burnout. Therefore, it is necessary to isolate the fully sulfidated hydrogenation catalyst to prevent direct exposure to an oxygen-containing atmosphere. Furthermore, newly sulfidated hydrogenation catalysts typically exhibit high initial activity during use, and the large amount of heat generated during hydrogenation makes the reaction process difficult to control, even causing bed overheating. Therefore, passivation treatment of the sulfidated hydrogenation catalyst is required.

[0006] Currently, hydrogenation catalyst passivation technologies mainly include three categories: gas-phase passivation, liquid-phase passivation, and solid-phase passivation. Among them, gas-phase passivation mainly uses oxidizing gases as the medium, oxidizing the catalyst at a certain temperature; liquid-phase passivation mainly uses organic hydrocarbons, which are supported on the catalyst through methods such as spraying and impregnation; solid-phase passivation involves dissolving the passivating agent on the catalyst surface to achieve the purpose of protection.

[0007] The paper "Gas-phase Passivation of Pre-sulfurized Hydrogenation Catalysts" (Acta Petrolei Sinica, 2008, 24(3):281-287) discloses a gas-phase sulfidation-passivation technology using an expanded bed reactor to sulfide and passivate diesel hydrogenation catalysts and cracked gasoline second-stage hydrogenation catalysts, respectively. The process mainly involves: placing a certain amount of catalyst in an expanded bed reactor and sulfiding the catalyst using H2S in a hydrogen-rich environment; after sulfidation, cooling the catalyst to the corresponding passivation temperature in a N2 atmosphere, and switching between O2 and N2 for passivation treatment according to a certain ratio; after the reaction is completed, cooling the catalyst to room temperature in a N2 atmosphere and transferring it to a sealed bottle for later use under N2 protection. This passivation method is a gas-phase passivation, and the passivation effect is not ideal. After passivation, the catalyst still needs to be stored in a sealed container for later use.

[0008] CN1816392A discloses an external treatment method for a hydrogenation catalyst, specifically proposing a method for externally treating a catalyst that requires reduction before use. The method includes: contacting the catalyst with at least one sulfur-containing reagent or agent; treating the catalyst with hydrogen at a temperature higher than ambient temperature; and passivating it. This involves oxidation treatment or passivation with a heavy, inert organic liquid (such as gas oil, hexadecane, etc.). The protective film formed by the liquid-phase passivating agent in this method can be removed during the reaction by heating and hydrogenolysis. However, because a heavy, inert organic liquid is used as the passivating agent, the subsequent post-treatment operation of the passivating agent becomes more demanding and increases processing costs, such as higher heating temperatures and longer raw material replacement cycles. This also has a certain impact on the quality of the target product.

[0009] The paper "Research on Paraffin Passivation Process of Pre-sulfurized Hydrogenation Catalysts" (Petroleum Refining and Chemical Industry, 2009, Vol. 40, No. 11) discloses a paraffin passivation process for pre-sulfurized hydrogenation catalysts. Under N2 protection, the sulfurized diesel hydrogenation catalyst is transferred to a conical flask. While stirring, the catalyst is heated to the passivation temperature using a programmed temperature rise method. A certain amount of paraffin powder is added, and the mixture is stirred to ensure thorough mixing. After passivation, the catalyst is cooled to room temperature in an N2 atmosphere. Although this method allows for catalyst surface drying without special protection and can be used under normal heating conditions in a hydrogen atmosphere, the passivating agent is solid at room temperature. This makes it prone to uneven distribution of the passivating agent coating on the catalyst surface, and even localized agglomeration, resulting in unsatisfactory passivation effects. More importantly, when the catalyst itself is not very strong, the stirring during the passivation process reduces the yield of the final catalyst product.

[0010] CN109675643A discloses a method for preparing a sulfide-state catalyst, the sulfide-state catalyst, and its applications. The passivation method includes passivation treatment a and passivation treatment b on the sulfide-state hydrogenation catalyst. Passivation treatment a uses distillate oil for passivation, and passivation treatment b uses an oxygen-containing substance for passivation. This scheme combines liquid-phase passivation and gas-phase passivation, i.e., liquid-phase passivation is used inside the catalyst pores, and gas-phase passivation is used on the catalyst surface. Although this passivation method meets the application requirements, the entire passivation process is relatively complex, needs to be completed in steps, and has no effect on regulating the reaction performance of the passivated catalyst.

[0011] Therefore, providing a new passivation method for sulfide-state hydrogenation catalysts is of great significance for improving the safety and reaction performance of sulfide-state hydrogenation catalysts. Summary of the Invention

[0012] This invention addresses the problems of existing catalyst passivation technologies, such as the complex pretreatment process of passivated catalysts during start-up, which prolongs the start-up cycle, and the need to improve the performance of passivated catalysts, especially the high initial activity and selectivity of hydrogenation reactions. It provides a passivation treatment method and application for sulfide-state hydrogenation catalysts.

[0013] To achieve the above objectives, the first aspect of the present invention provides a method for passivating a sulfide-state hydrogenation catalyst, comprising: supporting a passivating agent on the sulfide-state hydrogenation catalyst to obtain a passivated catalyst; wherein the passivating agent comprises a solute and a solvent;

[0014] The solute is wax; the solvent is a light petroleum product.

[0015] The second aspect of this invention provides the application of the passivation method described in the first aspect in the hydrotreating of oil products.

[0016] Through the above technical solution, the present invention has the following beneficial effects:

[0017] (1) The passivation method for sulfide-state hydrogenation catalysts provided by this invention has excellent passivation effect, effectively preventing the interaction between oxygen in the air and metal sulfides in the catalyst pores, thereby significantly improving the safety of the catalyst in packaging, storage, transportation and filling processes, meeting the needs of catalyst manufacturers and users. This method is particularly effective in improving the safety and performance of fully sulfide-state hydrogenation catalysts outside the reactor.

[0018] (2) The passivation method of the sulfide hydrogenation catalyst provided by the present invention can solve the problem of high initial activity of the catalyst during hydrogenation, avoid the "runaway temperature" of the reaction bed in the early stage of start-up, realize the "slow release" of activity, and thus ensure the long-term stable operation of the catalyst.

[0019] (3) The passivation method of the sulfurized hydrogenation catalyst provided by the present invention has a composition and properties of solute and solvent in the passivating agent that are similar to those of the hydrogenation reaction feedstock. After the catalyst is passivated, it can be directly used in oil. After the passivated catalyst is fed, qualified products can be produced quickly. There is no need to consider the problem that the pretreatment process of the passivated catalyst is complicated when it is fed into the plant, which will prolong the start-up cycle from feeding to the production of qualified products. This further eliminates the negative impact of the introduction of the passivating agent on the quality of hydrogenation products and greatly reduces the amount of by-products such as sludge and oil.

[0020] (4) The passivation method of the sulfide hydrogenation catalyst provided by the present invention is simple to operate, the passivation effect is controllable, and the process cost is economical. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0022] Figure 1 shows the appearance of the passivated catalyst obtained in Example 1 of the present invention (polarizing microscope).

[0023] Figure 2 shows the surface self-heating temperature curves of the passivated catalyst and the unpassivated fully sulfidated hydrogenation catalyst obtained in Example 1 and Comparative Example 1 of the present invention after contact with air. Detailed Implementation

[0024] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0025] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0026] The first aspect of the present invention provides a method for passivating a sulfide-state hydrogenation catalyst, comprising: supporting a passivating agent on the sulfide-state hydrogenation catalyst to obtain a passivated catalyst; wherein the passivating agent comprises a solute and a solvent;

[0027] The solute is wax; the solvent is a light petroleum product.

[0028] According to the present invention, the passivation method for the sulfurized hydrogenation catalyst has a broad definition for the wax, and various wax products produced by animals, plants, or minerals can be used, such as at least one of paraffin wax (a mineral wax), microcrystalline wax (a petroleum wax), Fischer-Tropsch wax (a synthetic wax), and polyethylene wax (a synthetic wax). Considering multiple influencing factors such as reducing by-products after catalyst addition, controlling the initial activity of the catalyst, and improving the cost-effectiveness of the process, paraffin wax is preferably used. Paraffin wax is a mixture of hydrocarbons with approximately 18-30 carbon atoms, its main components being straight-chain alkanes (approximately 80-95%), and containing small amounts of branched alkanes and monocyclic cycloalkanes with long side chains. Paraffin wax has a high melting point and is classified according to its melting point, including grades such as 52#, 54#, 56#, 58#, and 60#, exhibiting good thermal and chemical stability.

[0029] In this invention, the definition of paraffin wax is relatively broad. From the perspective of the degree of processing and refining, fully refined paraffin wax, semi-refined paraffin wax, or crude paraffin wax are all acceptable.

[0030] According to the present invention, in the passivation method of the sulfurized hydrogenation catalyst, the light petroleum product is a product oil obtained by refining light distillate oil. The light distillate oil refers to a low-boiling-point (boiling point below 370°C) petroleum product obtained by distilling crude oil during the refining process. The refining process refers to removing impurities (such as compounds containing sulfur, nitrogen, and oxygen), gums, and unsaturated hydrocarbons from the oil, and may include, but is not limited to, catalytic refining, adsorption refining, and solvent absorption refining.

[0031] According to some embodiments of the present invention, preferably, the light petroleum product may be selected from at least one of naphtha, gasoline, diesel, topping oil, and residual oil. More preferably, the light petroleum product may be C5-C. 10 Naphtha fraction and / or C5-C 10 Distilled gasoline.

[0032] According to some embodiments of the present invention, preferably, the light petroleum product may also be C5-C. 12 The single fraction of hydrocarbon can be selected from n-octane, n-decane, n-undecane, or n-dodecane. More preferably, the light petroleum product can be n-decane.

[0033] In this invention, naphtha, gasoline, diesel, topping oil, and raffinate oil can all be understood according to definitions known in the art. Specifically, naphtha refers to a light oil produced from crude oil and other raw materials and used as a chemical feedstock. Gasoline refers to a volatile and flammable liquid mixture of hydrocarbons obtained from petroleum fractionation and cracking, which can be used as fuel. Diesel refers to the 180-370℃ fraction of petroleum (density 0.81-0.86 g / mL), which can be obtained by blending straight-run diesel and secondary processed diesel, and sometimes may also include some cracking products. Topping oil refers to a light fraction with a boiling point below 60℃ obtained during the distillation of straight-run gasoline. Raffinate oil refers to the product oil obtained during petroleum processing by reforming refined or cracked gasoline fractions with platinum, removing aromatics, and extracting the 60-90℃ fraction from the resulting product.

[0034] According to the present invention, in the passivation method of the sulfurized hydrogenation catalyst, the chemical composition and physicochemical properties of both the solute and solvent in the passivating agent are similar to those of conventional hydrogenation reaction feedstock oil. This allows the passivated catalyst to be directly used in oil. Compared with the method of passivating the catalyst with heavy inert organic liquid, the amount of by-products such as sludge oil generated can be greatly reduced, the replacement time is short, and qualified products can be quickly produced after the passivated catalyst is fed in, which can basically eliminate the impact of the passivating agent on the quality of hydrogenation products.

[0035] According to the present invention, the specific selection of the light petroleum product used as the solvent for the passivating agent, while satisfying the above-mentioned limitations, can be determined based on the specific type of feedstock oil for the subsequent hydrotreating reaction. Preferably, the light petroleum product is the same as or similar to the feedstock oil for the hydrotreating reaction in terms of its composition or properties. For example, when the passivated catalyst is used for gasoline hydrotreating, it is preferable to use a whole gasoline fraction or a fraction of gasoline as the solvent for the passivating agent.

[0036] According to the present invention, in the passivating agent, the weight ratio of solute to solvent is (1-20):100, which enables the passivating agent to have better physical properties (such as stability, flowability, etc.) and better passivation effect.

[0037] According to a preferred embodiment of the present invention, in the passivating agent, the weight ratio of solute to solvent is (3-10):100, which is more conducive to the support of the passivating agent on the catalyst and brings better passivation effect.

[0038] According to the present invention, in the passivation method of the sulfide-state hydrogenation catalyst, the preparation method of the passivating agent includes: mixing the solute and the solvent to obtain the passivating agent.

[0039] According to a preferred embodiment of the present invention, the passivating agent can be prepared by stirring and mixing the solute and solvent together at a certain temperature, so that the solute is completely dissolved in the solvent to form a uniform, stable and fluid mixture system, thereby obtaining the passivating agent.

[0040] According to the present invention, in the preparation method of the passivating agent, preferably, the mixing temperature can be 40-65°C, which is beneficial to obtain a passivating agent with uniform and stable composition, thereby bringing about a better passivation effect.

[0041] According to the present invention, in the passivation method of the sulfurized hydrogenation catalyst, by controlling the weight ratio of the passivating agent to the sulfurized hydrogenation catalyst, the thickness of the passivation layer on the catalyst surface can be effectively controlled, thereby improving the passivation effect. Specifically, on the one hand, it can effectively prevent the interaction between oxygen in the air and the catalyst, improving the safety of its use in packaging, storage, transportation, and filling; on the other hand, it can solve the problem of high catalyst activity at the initial stage of start-up, avoiding "temperature runaway" of the reaction bed. Preferably, the weight ratio of the passivating agent to the sulfurized hydrogenation catalyst is (10-60):100, more preferably (15-30):100.

[0042] According to the present invention, in the passivation method of the sulfide-state hydrogenation catalyst, preferably, the temperature used for the support is 40-100°C, which can keep the passivating agent in a stable state and prevent the solute from precipitating out of the solvent during the support process.

[0043] According to the present invention, in the passivation method of the sulfide-state hydrogenation catalyst, the loading method includes, but is not limited to, impregnation or spraying.

[0044] In this invention, the definition of impregnation is relatively broad, and conventional impregnation methods can be used. According to a preferred embodiment of the invention, the impregnation process includes: impregnating the passivating agent onto the sulfide-state hydrogenation catalyst. Specifically, firstly, the saturated water absorption rate of the sulfide-state hydrogenation catalyst is tested, and the amount of passivating agent added is determined based on the saturated water absorption rate; then, under a protective atmosphere (oxygen-free), the sulfide-state hydrogenation catalyst is introduced into a container; finally, the passivating agent is introduced into the container to impregnate and support the sulfide-state hydrogenation catalyst.

[0045] In this invention, the definition of spraying is relatively broad, and conventional spraying methods can be used. According to a preferred embodiment of the invention, the spraying process includes: spraying the passivating agent onto the sulfide-state hydrogenation catalyst. Specifically, the saturated water absorption rate of the sulfide-state hydrogenation catalyst can be tested first, and the amount of passivating agent added can be determined based on the saturated water absorption rate; then, under a protective atmosphere (oxygen-free), the sulfide-state hydrogenation catalyst is introduced into a container; finally, the passivating agent is introduced into the container in an atomized spray manner to spray and support the sulfide-state hydrogenation catalyst.

[0046] According to the present invention, the loading is preferably carried out by spraying, which facilitates the uniform loading of the passivating agent on the catalyst, so that the weight of the passivating agent distributed on each catalyst particle is theoretically basically equal, avoiding excessive or insufficient local loading of passivating agent, and achieving a better passivation effect.

[0047] In this invention, preferably, the loading is carried out under drum rotation conditions, which is more conducive to obtaining a uniform passivation protective layer. Preferably, the drum rotation speed is 20-150 rpm.

[0048] According to the present invention, in the passivation method of the sulfurized hydrogenation catalyst, after the passivating agent is supported on the sulfurized hydrogenation catalyst, it is cooled down (it can be cooled naturally or by conventional cooling methods, usually cooled to the storage temperature of the passivating catalyst, such as room temperature). As the surface temperature of the catalyst gradually decreases, the solute in the passivating agent is rapidly precipitated, forming a protective layer of a certain thickness on the surface of the catalyst, thus obtaining the passivated catalyst.

[0049] The passivated catalyst obtained by the passivation method of the sulfide-state hydrogenation catalyst provided by this invention has a protective layer thickness that can be controlled between 0.5-15 μm, preferably 4-12 μm, and the protective layer thickness is uniform. If the protective layer is too thin, it will affect the passivation effect and cannot effectively suppress the interaction between oxygen in the air and the metal sulfides on the catalyst surface; if the protective layer is too thick, it will increase the cost of catalyst passivation treatment and prolong the feeding replacement time when using the passivated catalyst for subsequent catalytic hydrogenation reactions.

[0050] In this invention, the thickness of the protective layer on the surface of the passivation catalyst can be measured using a polarizing microscope, such as the BM2100POL(T) polarizing microscope from Jiangnan Yongxin Optics. During the measurement of the protective layer thickness, because the protective wax has a certain degree of plasticity at room temperature, it easily causes cross-sectional deformation when processing the catalyst cross-section, thus affecting the observation and measurement of the protective layer thickness. Therefore, pretreatment of the passivation catalyst sample is required. The pretreatment process includes: placing the passivation catalyst sample in a freeze dryer for freeze-drying at a temperature of -50 to -10°C for 4-10 hours, taking a cross-section, and observing and measuring the protective layer thickness using a polarizing microscope.

[0051] In some embodiments of the present invention, the passivation method of the sulfide-state hydrogenation catalyst further includes: after loading, purging the catalyst loaded with the passivating agent using a protective gas. This purging process can, on the one hand, rapidly cool the catalyst, accelerating the precipitation of solute from the passivating agent to form a protective layer; on the other hand, it can keep the surface of the obtained passivated catalyst in a slightly dry state, preventing the catalyst from becoming too wet and causing adhesion, caking, or other phenomena that would inconvenience the subsequent loading process.

[0052] In this invention, the slightly dry state refers to a state in which the surface of the catalyst particles is between wet and dry. In this state, the catalyst exists as independent particles, and the particles do not stick together or clump together.

[0053] In this invention, the sulfide-state hydrogenation catalyst refers to a catalyst in which a sulfiding agent is fully filled into the pores of the catalyst particles before the catalyst is loaded into the hydrogenation reactor, and after reaction, it is combined with the active metal component of the catalyst in the form of sulfides (the catalyst has been sulfided). This invention does not particularly limit the source and composition of the sulfide-state hydrogenation catalyst; it can be obtained by sulfidation reduction treatment of any hydrogenation catalyst (oxidized state) capable of hydrogenating materials.

[0054] In some embodiments of the present invention, the hydrogenation catalyst (oxidized state) may include a support and an active metal oxide; wherein, based on 100 parts by weight of the total weight of the hydrogenation catalyst (oxidized state), the support comprises 60-98 parts by weight and the active metal oxide comprises 2-40 parts by weight.

[0055] Preferably, the carrier can be a single carrier or a composite carrier prepared by alumina, amorphous silica-alumina, molecular sieve, aluminum sol or silica sol in a single or compound form;

[0056] Preferably, the active metal oxide may be selected from oxides of Group VIB metals and / or oxides of Group VIII metals; wherein the Group VIB metal is preferably Mo and / or W, and the Group VIII metal is preferably Co and / or Ni.

[0057] In some embodiments of the present invention, preferably, the hydrogenation catalyst (oxidized state) further comprises an auxiliary agent; the auxiliary agent may be selected from at least one of oxides of Group IA metals, oxides of Group IIA metals, oxides of Group IIIA metals, and oxides of Group VA metals. Preferably, the Group IA metal may be selected from Li and / or K; the Group IIA metal may be selected from Mg and / or Ca; the Group IIIA metal may be selected from B and / or Ga; and the Group VA metal may be P.

[0058] Preferably, based on 100 parts by weight of the total weight of the hydrogenation catalyst (oxidized state), the support (γ-alumina) is 65-90 parts by weight; the active metal oxide cobalt oxide is 1-5 parts by weight; the active metal oxide molybdenum oxide is 2-15 parts by weight; the auxiliary agent potassium oxide is 0.1-4.5 parts by weight; and the auxiliary agent magnesium oxide is 0.1-4.5 parts by weight.

[0059] More preferably, based on 100 parts by weight of the total weight of the hydrogenation catalyst (oxidized state), the support (γ-alumina) is 75-85 parts by weight; the active metal oxide cobalt oxide is 1-3 parts by weight; the active metal oxide molybdenum oxide is 5-12 parts by weight; the auxiliary agent potassium oxide is 0.5-2.5 parts by weight; and the auxiliary agent magnesium oxide is 2.5-4.5 parts by weight.

[0060] In this invention, there is no particular limitation on the source of the hydrogenation catalyst (oxidized state). It can be prepared by known methods such as kneading, impregnation and spraying (e.g., the preparation methods disclosed in CN116020501A or CN115999618A), or it can be obtained commercially.

[0061] In this invention, there are no particular limitations on the sulfidation reduction treatment of the hydrogenation catalyst (oxidized state), and known processes such as dry sulfidation and wet sulfidation can be used.

[0062] In this invention, the dry sulfidation and wet sulfidation can be carried out using any known process and parameters in the art. For example, the dry sulfidation method disclosed in "Development and Industrial Application of External True Sulfidation Technology for Hydrogenation Catalysts" (Acta Petrolei Sinica (Petroleum Processing), Vol. 37, No. 6, 2021) uses a mixed gas of hydrogen sulfide and hydrogen in a volume ratio of 3:97 as the sulfidation medium, and a mixed oil of carbon disulfide and kerosene in a mass ratio of 5:95 as the sulfidation medium. The sulfidation heating program is the same, the sulfidation temperature is 320°C, the sulfidation time is 4 hours, the sulfidation pressure is 6.4 MPa, and after sulfidation, the temperature is lowered to room temperature, and the catalyst is taken out for use under nitrogen protection.

[0063] The passivation method for sulfide-state hydrogenation catalysts provided by this invention employs a specific liquid passivating agent, using wax as the solute and light petroleum products as the solvent, which is attached to the catalyst via a supporting manner to achieve passivation. Both the solute and solvent in the passivating agent have chemical compositions and physicochemical properties similar to those of conventional hydrogenation reaction feedstocks. The passivated catalyst can be directly used in oil applications, resulting in short start-up replacement time, minimal oil waste, and low environmental pollution, effectively eliminating the negative impact of the passivating agent on the quality of hydrogenation products. The passivating agent uses a combination of "wax + light petroleum products". During the passivating agent loading process, the solvent (light petroleum products) selectively enters the pores of the catalyst through the adsorption effect of the catalyst carrier channels. The solute (wax) dissolved in the solvent initially penetrates into the catalyst channels along with the solvent. However, as the surface temperature of the catalyst gradually decreases after loading, the solute will quickly precipitate from the inside of the catalyst, forming a dense and uniform protective layer on the catalyst surface. This effectively prevents oxygen in the air from interacting with the metal sulfides in the catalyst channels. The retention of the passivating agent in the catalyst channels and on the surface can be optimized by adjusting the proportion of solute in the passivating agent and the loading amount of the passivating agent on the catalyst, thereby achieving controllable passivation effect. In addition, the protective layer on the surface of the passivated catalyst can be quickly dissolved in the hydrogenation reaction feedstock after oil is added, and the solvent that penetrates into the catalyst channels (especially the micropores that are not conducive to material mass transfer) will be partially "locked in", selectively covering some active sites. This not only solves the problem of high catalyst activity at the beginning of operation and achieves the purpose of "slow release" of activity, but also improves the mass transfer efficiency of materials in the catalyst channels and improves the hydrogenation selectivity of the catalyst.

[0064] The passivation method for sulfide-state hydrogenation catalysts provided by this invention has excellent passivation effects on various sulfide-state hydrogenation catalysts, especially on fully sulfide-state hydrogenation catalysts with high oxygen affinity, which can effectively passivate them, improve their safety in use, improve the initial activity and selectivity of hydrogenation at start-up, and reduce the wear and tear of catalysts during feeding.

[0065] The second aspect of this invention provides the application of the passivation method described in the first aspect in the hydrotreating of oil products.

[0066] According to the present invention, the hydrogenation treatment includes, but is not limited to, at least one of hydrogenation refining, hydrogenation modification, hydrocracking and selective hydrogenation.

[0067] The passivation method provided by this invention can effectively protect sulfided hydrotreating catalysts (especially fully sulfided hydrotreating catalysts), improve the safety of the catalysts during packaging, storage, transportation, and filling, and avoid the risk of oxidative spontaneous combustion caused by the catalysts coming into contact with oxygen-containing gases. When applied to oil hydrotreating, this passivation method can improve the quality of hydrotreated products, giving the hydrotreating catalyst suitable initial activity and good hydrotreating selectivity, and preventing "runaway temperatures" in the reaction bed during the initial startup phase.

[0068] The present invention will be described in detail below through examples. Unless otherwise specified, the following examples and comparative examples are all conventional methods; the reagents and materials used are commercially available unless otherwise specified.

[0069] Fully sulfurized hydrogenation catalyst (Cat-1): Carbon disulfide is used as the sulfurizing agent, and naphtha containing 2% by weight of carbon disulfide (olefin content ≤ 1 volume, impurities such as arsenic and chlorine content ≤ 100 μg / kg) is used as the sulfurizing oil. Catalyst A (based on a total weight of 100 parts by weight of oxidized catalyst A, 81.3 parts by weight of γ-alumina support; 2.8 parts by weight of cobalt oxide, 10.3 parts by weight of molybdenum oxide, 2.1 parts by weight of potassium oxide, and 3.5 parts by weight of magnesium oxide) was placed in a sulfidation reactor. In the presence of nitrogen, the temperature was increased from 25°C to 150°C at a rate of 20°C / h and held for 2 hours. Then, the nitrogen was switched to hydrogen, and sulfidation oil was injected. The temperature was increased to 230°C after 4 hours and held for 4 hours. After another 2.5 hours, the temperature was increased to 280°C and held for 8 hours. Finally, the temperature was increased to 320°C and held for 4 hours, completing the sulfidation process and yielding the fully sulfidated hydrogenation catalyst Cat-1. During the sulfidation process, the pressure was 3 MPa and the sulfidation oil space velocity was 3 h⁻¹. -1 The hydrogen-to-oil volume ratio is 300:1.

[0070] Fully sulfided hydrogenation catalyst (denoted as Cat-2): Using catalyst B (based on a total weight of 100 parts by weight of oxidized catalyst B, 78.6 parts by weight of γ-alumina support; 4.2 parts by weight of active metal oxide cobalt oxide; 13.9 parts by weight of active metal oxide molybdenum oxide; 0.8 parts by weight of auxiliary potassium oxide; and 2.5 parts by weight of auxiliary magnesium oxide), the fully sulfided hydrogenation catalyst Cat-2 was obtained by sulfidation treatment under the same method and conditions as catalyst A.

[0071] Paraffin wax: grades 52#, 54#, and 60#.

[0072] Fischer-Tropsch wax: commercially available, with approximately 18-30 carbon atoms and a melting point of 50-70℃.

[0073] Microcrystalline wax: Commercially available, with approximately 18-30 carbon atoms and a melting point of 60-90℃.

[0074] Gasoline: Gasoline obtained from the catalytic hydrodesulfurization unit of a refinery, with approximately C5-C6 carbon atoms. 12 Its distillation range is 54.3-202.1℃.

[0075] Diesel fuel: Diesel fuel extracted from a diesel hydrorefining unit, with approximately C8-C carbon atoms. 15 Its distillation range is 163.7-330.5℃.

[0076] Naphtha: Naphtha extracted from the reforming unit of a refinery, with approximately C5-C6 carbon atoms. 13 Its distillation range is 61.8-198.3℃.

[0077] n-Decane: Commercially available, purity ≥98%.

[0078] Example 1

[0079] (1) Preparation of passivating agent: Place 54# paraffin and n-decane together in a container, control the container temperature to 52℃, stir thoroughly to mix, so that 54# paraffin is completely dissolved in n-decane, and obtain a uniform and stable liquid passivating agent.

[0080] The weight ratio of 54# paraffin to n-decane is 10:100.

[0081] (2) Under a nitrogen atmosphere, the catalyst Cat-1 is introduced into the drum (the drum is kept rotating), and the above liquid passivating agent is introduced into the drum by atomization spray to spray and support the catalyst Cat-1 (the support temperature is 63℃).

[0082] The weight ratio of catalyst Cat-1 to passivator is 100:15; the rotation speed of the drum is 75 rpm.

[0083] (3) Nitrogen gas is introduced to purge and cool the catalyst loaded with passivating agent obtained in step (2) until the catalyst surface is slightly dry and the particles do not stick together or clump together, thus obtaining the passivated catalyst (denoted as P1).

[0084] The cross-section of the passivated catalyst P1 was observed using a polarizing microscope, as shown in Figure 1. As can be seen from Figure 1, the surface of the catalyst P1 is covered with a protective layer with an average thickness of about 10.5 μm.

[0085] Example 2

[0086] (1) Preparation of passivating agent: Place 54# paraffin wax and gasoline in a container, control the container temperature to 60℃, stir thoroughly to mix, so that 54# paraffin wax is completely dissolved in gasoline, and obtain a uniform and stable liquid passivating agent.

[0087] The weight ratio of 54# paraffin wax to gasoline is 3:100.

[0088] (2) Under a nitrogen atmosphere, the catalyst Cat-1 is introduced into the drum (the drum is kept rotating), and the above liquid passivating agent is introduced into the drum by atomization spray to spray and support the catalyst Cat-1 (the support temperature is 58℃).

[0089] The weight ratio of catalyst Cat-1 to passivator is 100:30; the rotation speed of the drum is 120 rpm.

[0090] (3) Nitrogen gas is introduced to purge and cool the catalyst loaded with passivating agent obtained in step (2) until the catalyst surface is slightly dry and the particles do not stick together or clump together, thus obtaining a passivated catalyst (denoted as P2, the average thickness of the surface protective layer of P2 is about 6.8 μm).

[0091] Example 3

[0092] (1) Preparation of passivating agent: Place 52# paraffin wax and gasoline in a container, control the container temperature to 46℃, stir thoroughly to mix, so that 52# paraffin wax is completely dissolved in gasoline, and obtain a uniform and stable liquid passivating agent.

[0093] The weight ratio of 52# paraffin wax to gasoline is 14.5:100.

[0094] (2) Under a nitrogen atmosphere, the catalyst Cat-2 is introduced into the drum (the drum is kept rotating), and the above liquid passivating agent is introduced into the drum by atomization spray to spray and support the catalyst Cat-2 (the support temperature is 45℃).

[0095] The weight ratio of catalyst Cat-2 to passivator is 100:10; the rotation speed of the drum is 145 rpm.

[0096] (3) Nitrogen gas is introduced to purge and cool the catalyst loaded with passivating agent obtained in step (2) until the catalyst surface is slightly dry and the particles do not stick together or clump together, thus obtaining a passivated catalyst (denoted as P3, the average thickness of the surface protective layer of P3 is about 9.1 μm).

[0097] Example 4

[0098] (1) Preparation of passivating agent: Place 60# paraffin wax and naphtha together in a container, control the container temperature to 57℃, stir thoroughly to mix, so that 60# paraffin wax is completely dissolved in naphtha, and obtain a uniform and stable liquid passivating agent.

[0099] The weight ratio of 60# paraffin wax to naphtha is 2.5:100.

[0100] (2) Under a nitrogen atmosphere, the catalyst Cat-1 is introduced into the drum (the drum is kept rotating), and the above liquid passivating agent is introduced into the drum by atomization spray to spray and support the catalyst Cat-1 (the support temperature is 100℃).

[0101] The weight ratio of catalyst Cat-1 to passivator is 100:60; the rotation speed of the drum is 90 rpm.

[0102] (3) Nitrogen gas is introduced to purge and cool the catalyst loaded with passivating agent obtained in step (2) until the catalyst surface is slightly dry and the particles do not stick together or clump together, thus obtaining a passivated catalyst (denoted as P4, the average thickness of the surface protective layer of P4 is about 12.5 μm).

[0103] Example 5

[0104] (1) Preparation of passivating agent: Place Fischer-Tropsch wax and diesel oil together in a container, control the container temperature to 65°C, stir thoroughly to mix, so that Fischer-Tropsch wax is completely dissolved in diesel oil, and obtain a uniform and stable liquid passivating agent.

[0105] The weight ratio of Fischer-Tropsch wax to diesel oil is 20:100.

[0106] (2) Under a nitrogen atmosphere, the catalyst Cat-1 is introduced into the drum (the drum is kept rotating), and the above liquid passivating agent is introduced into the drum by atomization spray to spray and support the catalyst Cat-1 (the support temperature is 72°C).

[0107] The weight ratio of catalyst Cat-1 to passivator is 100:12.5; the rotation speed of the drum is 115 rpm.

[0108] (3) Nitrogen gas is introduced to purge and cool the catalyst loaded with passivating agent obtained in step (2) until the catalyst surface is slightly dry and the particles do not stick together or clump together, thus obtaining a passivated catalyst (denoted as P5, the average thickness of the surface protective layer of P5 is about 14.7 μm).

[0109] Example 6

[0110] (1) Preparation of passivating agent: Place microcrystalline wax and n-decane together in a container, control the container temperature to 40℃, stir thoroughly to mix, so that the microcrystalline wax is completely dissolved in n-decane, and obtain a uniform and stable liquid passivating agent.

[0111] The weight ratio of microcrystalline wax to n-decane is 1:100.

[0112] (2) Under a nitrogen atmosphere, the catalyst Cat-1 is introduced into the drum (the drum is kept rotating); the above liquid passivating agent is introduced into the drum to impregnate and support the catalyst Cat-1 (the supporting temperature is 50°C);

[0113] The weight ratio of catalyst Cat-1 to passivator is 100:47.5; the rotation speed of the drum is 90 rpm.

[0114] (3) Nitrogen gas is introduced to purge and cool the catalyst loaded with passivating agent obtained in step (2) until the catalyst surface is slightly dry and the particles do not stick together or clump together, thus obtaining a passivated catalyst (denoted as P6, the average thickness of the surface protective layer of P6 is about 2.6 μm).

[0115] Example 7

[0116] (1) Preparation of passivating agent: Place microcrystalline wax and n-decane together in a container, control the container temperature to 65℃, stir thoroughly to mix, so that the microcrystalline wax is completely dissolved in n-decane, and obtain a uniform and stable liquid passivating agent.

[0117] The weight ratio of microcrystalline wax to n-decane is 1:100.

[0118] (2) Under a nitrogen atmosphere, the catalyst Cat-1 is introduced into the drum (the drum is kept rotating); the above liquid passivating agent is introduced into the drum to impregnate and support the catalyst Cat-1 (the supporting temperature is 50°C);

[0119] The weight ratio of catalyst Cat-1 to passivator is 100:35.5; the rotation speed of the drum is 90 rpm.

[0120] (3) Nitrogen gas is introduced to purge and cool the catalyst loaded with passivating agent obtained in step (2) until the catalyst surface is slightly dry and the particles do not stick together or clump together, thus obtaining a passivated catalyst (denoted as P7, the average thickness of the surface protective layer of P7 is about 2.1 μm).

[0121] Example 8

[0122] (1) Preparation of passivating agent: Place microcrystalline wax and n-decane together in a container, control the container temperature to 65℃, stir thoroughly to mix, so that the microcrystalline wax is completely dissolved in n-decane, and obtain a uniform and stable liquid passivating agent.

[0123] The weight ratio of microcrystalline wax to n-decane is 1:100.

[0124] (2) Under a nitrogen atmosphere, the catalyst Cat-1 is introduced into the drum (the drum is kept rotating); the above liquid passivating agent is introduced into the drum to impregnate and support the catalyst Cat-1 (the supporting temperature is 50°C);

[0125] The weight ratio of catalyst Cat-1 to passivator is 100:9.5; the rotation speed of the drum is 90 rpm.

[0126] (3) Nitrogen gas is introduced to purge and cool the catalyst loaded with passivating agent obtained in step (2) until the catalyst surface is slightly dry and the particles do not stick together or clump together, thus obtaining a passivated catalyst (denoted as P8, the average thickness of the surface protective layer of P8 is about 0.9 μm).

[0127] Comparative Example 1

[0128] (1) Under a nitrogen atmosphere, the catalyst Cat-1 is introduced into the drum (the drum is kept rotating), and n-decane is introduced into the drum as a passivating agent by atomization spray to support the catalyst Cat-1 (the support temperature is 25℃).

[0129] The weight ratio of the sulfide-state hydrogenation catalyst Cat-1 to n-decane is 100:15; the rotation speed of the drum is 75 rpm.

[0130] (2) Nitrogen gas is introduced to purge and cool the catalyst loaded with passivating agent obtained in step (1) until the catalyst surface is slightly dry and the particles do not stick together or clump together, thus obtaining the passivated catalyst (denoted as DP1).

[0131] Comparative Example 2

[0132] (1) Under a nitrogen atmosphere, the catalyst Cat-1 was introduced into the drum (the drum was kept rotating), and liquid 54# paraffin was introduced into the drum as a passivating agent by atomization spray to support the catalyst Cat-1 (the support temperature was 63℃).

[0133] The weight ratio of the sulfide-state hydrogenation catalyst Cat-1 to the liquid 54# paraffin is 100:15; the rotation speed of the drum is 75 rpm.

[0134] (2) Nitrogen gas is introduced to purge and cool the catalyst loaded with passivating agent obtained in step (1) until the catalyst surface is slightly dry, and the passivating catalyst (denoted as DP2) is obtained.

[0135] The protective layer thickness on the outer surface of different catalyst particles in DP2 is uneven, and local caking occurs.

[0136] Test case

[0137] 1. Surface self-heating temperature test

[0138] The passivated catalysts P1-P8, DP1-DP2 prepared in the above examples and comparative examples, as well as the unpassivated fully sulfurized hydrogenation catalyst Cat-1, were completely exposed to the same ambient air environment. The surface autothermal temperature of each catalyst (referring to the actual surface temperature of the catalyst after contact with air) was measured using an infrared thermometer from the start of contact with air until a contact time of 60 minutes. The highest surface autothermal temperatures of each catalyst are shown in Table 1. The surface autothermal temperature curves of catalysts P1, DP1, and Cat-1 are shown in Figure 2.

[0139] Table 1

[0140] As shown in Table 1, the passivation method of this invention effectively prevents the catalyst from releasing heat in the air, and the self-heating temperature of the catalyst surface does not exceed 60°C. As shown in Figure 2, when the passivated catalyst P1 obtained using the passivation method of this invention is fully exposed to the air environment, no heat release occurs, and the catalyst surface temperature remains stable. After 60 minutes of exposure, the catalyst surface temperature shows almost no increase, demonstrating excellent passivation effect. In contrast, catalysts DP1 and CAT-1 both exhibit concentrated heat release, with rapid temperature rise on the catalyst surface.

[0141] 2. Catalytic performance test

[0142] Hydrorefining experiments were conducted on feedstock oils using the passivated catalysts P1-P8 and DP1-DP2 obtained in Examples 1-8 and Comparative Examples 1-2, as well as the unpassivated fully sulfurized hydrogenation catalyst Cat-1. The experimental procedures are as follows:

[0143] The above catalysts were loaded into 50 mL fixed-bed adiabatic reactors. Pressure and airtightness tests were conducted on the reactors using N2 and H2. After passing the tests, straight-run naphtha and H2 were introduced to wet the reactor bed and flush out impurities and dust introduced during the loading process. Then, the temperature was increased at a rate controlled within the range of 15-30 °C / h until the reaction operating conditions were reached: inlet temperature 250 °C, pressure 2.0 MPa, and volumetric hourly space velocity (VHSV) 3.6 h⁻¹. -1The hydrogen-to-oil volume ratio was 200:1, and feedstock oil was introduced. After the feedstock was introduced, the reaction system was stabilized under the above conditions, and the performance of the hydrogenated product oil after 250 h of reaction using catalysts P1-P8, DP1-DP2, and Cat-1 was measured, including the product desulfurization rate, olefin saturation rate, and research octane number (RON). The results are shown in Table 2.

[0144] The feedstock is Lanzhou Petrochemical catalytic heavy gasoline, with a sulfur content of 209.3 mg / kg, an olefin content of 16.34 v%, and an RON content of 89.2%.

[0145] The sulfur content of the oil was determined using a TSN-2000 sulfur-nitrogen analyzer; the composition of the oil was determined using an Agilent 7890B gas chromatograph, and data processing was performed using an HW-2000PONA analytical chromatography workstation; the research octane number (RON) of the oil was determined using an octane rating analyzer.

[0146] The desulfurization rate, olefin saturation rate, and research octane number (RON) loss are calculated using the following formula: Research octane number loss = Research octane number of reactants - Research octane number of products

[0147] Table 2

[0148] Note: In Table 2, start-up time refers to the time from when the feedstock is introduced into the reaction system to start system replacement and hydrogenation reaction, until the gasoline product at the unit outlet meets production requirements and the sulfur content and distillation range indicators are qualified.

[0149] As shown in Table 2, the catalyst passivation method provided by the present invention can not only solve the problem of complex pretreatment process of existing passivation catalysts during start-up, but also significantly shorten the start-up time, improve the initial reaction activity and hydrogenation selectivity of the passivated hydrogenation catalyst after start-up, and prevent "temperature runaway" in the reaction bed at the beginning of start-up. It can reduce olefin hydrogenation saturation while ensuring deep desulfurization of reactants and avoid significant loss of octane number.

[0150] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A passivation method for a sulfide-state hydrogenation catalyst, characterized in that, include: A passivating agent is supported on a sulfide-state hydrogenation catalyst to obtain a passivated catalyst; wherein the passivating agent comprises a solute and a solvent; The solute is wax; the solvent is a light petroleum product.

2. The method according to claim 1, wherein, The wax is selected from at least one of paraffin wax, microcrystalline wax, Fischer-Tropsch wax, and polyethylene wax.

3. The method according to claim 2, wherein, The wax is paraffin wax.

4. The method according to claim 1, wherein, The light petroleum product is a product oil obtained by refining light distillate oil.

5. The method according to claim 4, wherein, The light petroleum products are selected from naphtha, gasoline, diesel, topping oil, residue oil, and C5-C. 12 At least one of the single-fraction hydrocarbons.

6. The method according to any one of claims 1-5, wherein, The weight ratio of solute to solvent is (1-20):

100.

7. The method according to claim 6, wherein, The weight ratio of solute to solvent is (3-10):

100.

8. The method according to any one of claims 1-5, wherein, The weight ratio of the passivating agent to the sulfidated hydrogenation catalyst is (10-60):

100.

9. The method according to claim 8, wherein, The weight ratio of the passivating agent to the sulfide-state hydrogenation catalyst is (15-30):

100.

10. The method according to any one of claims 1-5, wherein, The method for preparing the passivating agent includes: mixing the solute and the solvent to obtain the passivating agent.

11. The method according to claim 10, wherein, The mixing temperature is 40-65℃.

12. The method according to any one of claims 1-5, wherein, The temperature used for the load is 40-100℃.

13. The method according to claim 12, wherein, The load is applied by immersion or spraying.

14. The method according to claim 13, wherein, The impregnation process includes: impregnating the passivating agent onto the sulfided hydrogenation catalyst under rotating drum conditions; And / or, the spraying process includes: spraying the passivating agent onto the sulfurized hydrogenation catalyst under drum rotation conditions.

15. The method according to any one of claims 1-5, wherein, The passivation method further includes: after loading, purging the catalyst loaded with the passivating agent using a protective gas; And / or, the surface protective layer thickness of the passivation catalyst is 0.5-15 μm.

16. The application of the passivation method according to any one of claims 1-15 in the hydrotreating of oil products.

17. The application according to claim 16, wherein, The hydrotreating process includes at least one of hydrorefining, hydromodification, hydrocracking, and selective hydrotreating.

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