Passivation method of sulfuration type catalytically cracked gasoline hydrodesulfurization catalyst, passivated catalyst and application of passivated catalyst

Abstract

The invention provides a passivation method of a sulfuration type catalytically cracked gasoline hydrodesulfurization catalyst, a passivated catalyst and application thereof, and the passivation method comprises the following steps: dissolving an organic peroxide in an organic solvent to form a passivation solution; under the condition of oxygen isolation, adding the sulfuration type catalytically cracked gasoline hydrodesulfurization catalyst into the passivation solution, and carrying out passivation reaction, so as to obtain the passivated catalyst after the passivation reaction is finished. The passivation method provided by the invention has the advantages of simple process and strong controllability, can improve the desulfurization activity of the sulfuration type catalytically cracked gasoline hydrodesulfurization catalyst, and solves the problems of uncontrollable passivation effect, complex startup pretreatment, low active center utilization rate and the like of the existing ex-situ passivation catalyst.

Description

Technical Field

[0001] This invention relates to a passivation method for a sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, the passivated catalyst and its application, belonging to the field of petrochemical catalyst processing technology. Background Technology

[0002] Catalytic hydrodesulfurization is the most commonly used desulfurization method in refineries due to its advantages of high desulfurization efficiency and low cost. Improving the activity of hydrodesulfurization catalysts and reducing their production and operating costs are key aspects of the research and application of hydrodesulfurization catalysts.

[0003] Oil hydrodesulfurization catalysts typically use alumina as a support, with Co(Ni)-Mo(W) metals loaded onto its surface as active components, followed by high-temperature calcination to obtain an oxidized catalyst. However, the surface metal elements of such catalysts only exhibit excellent catalytic hydrodesulfurization activity and stability under sulfided conditions. Sulfidation technology for hydrodesulfurization catalysts has evolved through three stages: in-reactor sulfidation, external pre-sulfidation, and external complete sulfidation. External complete sulfidation is currently the most advanced sulfidation technology. Before the catalyst is loaded into the reactor, it is completely sulfided externally using a sulfiding agent and hydrogen, converting the active metal components from the oxidized state to the sulfided state, thus ensuring high hydrodesulfurization activity upon loading into the reactor. This allows the reactor to rapidly heat up and begin producing qualified products once the feedstock is introduced. Both in-reactor and external sulfidation technologies utilize sulfiding reagents to convert the oxidized metal components into the sulfided state through chemical reactions. Traditional oxidized catalyst preparation employs a solid-liquid two-phase impregnation method to load Co(Ni)-Mo(W) metal into the pores of a support. During the conventional temperature-heating drying and solvent removal process, the solvent evaporates from the pores, causing the metal components to migrate to the outside. During high-temperature calcination to form metal oxides, this results in large metal particle clusters, leading to uneven distribution of the active components and limiting their desulfurization activity (see CN106179522A). Furthermore, for in-reactor sulfidation catalysts, approximately 48-72 hours of sulfidation treatment is required after loading into the reactor. This prolonged sulfidation time affects the normal operation and production of the unit (see CN104403685A).

[0004] For externally deposited fully sulfided catalysts, which exist in a reduced state, the high specific surface area of ​​the sulfided catalyst, when exposed to air and encountering O2, will generate SO2 and release a large amount of heat, showing a tendency to self-heat or burn below 200℃. Therefore, externally deposited sulfided catalysts pose safety risks during packaging, storage, and transportation, necessitating passivation treatment. Based on the state of the passivating agent, currently disclosed passivation technologies for sulfided metal catalysts mainly include gas-phase passivation and liquid-phase passivation. Gas-phase passivation uses O2 diluted with an inert gas to passivate the sulfided metal center, where some sulfur in the active metal sulfide microcrystals is replaced by oxygen, forming a metal oxysulfide protective film on its surface. Because O2 has strong oxidizing power, it quickly adsorbs onto the surface of the sulfided catalyst even at room temperature. The heat generated by the oxidation reaction is slowly conducted between the gas and solid phases, resulting in poor controllability of the passivation process and a larger, less uniform passivation layer thickness. Existing liquid-phase passivation processes involve loading organic oxygen-containing hydrocarbons or heavy hydrocarbons onto the surface of a sulfide-state catalyst through impregnation or spraying to form a protective film. This film isolates the catalyst surface from O2, preventing the metal sulfides from reacting with O2. The temperature during liquid-phase passivation should ensure that the viscosity of the passivating agent is low, allowing it to enter the catalyst pores at an appropriate rate. Strict control of the amount of passivating solution applied during liquid-phase passivation is crucial. Excessive application can lead to difficulty in removal during initial operation and negatively impact catalyst activity, while insufficient application will fail to effectively prevent O2 from penetrating the catalyst surface and pores.

[0005] CN104593051A discloses a method for impregnating a sulfurized hydrogenation catalyst with an organic complex solution of a Group VIII metal. After impregnation, the catalyst is heat-treated to form a protective film on its surface. This type of catalyst can exhibit hydrogenation activity after being treated with operating oil in an inert atmosphere and then switching to hydrogenation reaction pressure and temperature. However, its passivation process has poor controllability and high passivation cost.

[0006] CN112574775A uses hydrocarbon oils with a monocyclic aromatic hydrocarbon content greater than 90% to passivate hydrocracking catalysts, solving the problems of catalyst activation, excessive feedstock cracking, and high risk of bed overheating during start-up. However, the passivation process is complex and requires a large amount of passivating agent, resulting in high passivation costs. It is evident that currently disclosed gas-phase and liquid-phase passivation technologies offer poor controllability, high costs, and require further improvement in passivation effectiveness for the metal sulfide active phase of hydrodesulfurization catalysts.

[0007] Therefore, providing a novel passivation method for a sulfurized catalytic cracking gasoline hydrodesulfurization catalyst, as well as the passivated catalyst and its application, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] To address the aforementioned shortcomings and deficiencies, the present invention aims to provide a passivation method for a sulfur-based catalytic cracking gasoline hydrodesulfurization catalyst, as well as the passivated catalyst and its applications. The external passivation method of the present invention has the advantages of simple process and strong controllability, and can improve the desulfurization activity of the sulfur-based catalytic cracking gasoline hydrodesulfurization catalyst, solving the problems of uncontrollable passivation effect, complex start-up pretreatment, and low utilization rate of active centers in existing external passivation catalysts.

[0009] To achieve the above objectives, on the one hand, the present invention provides a passivation method for a sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, wherein the passivation method includes:

[0010] Organic peroxides are dissolved in organic solvents to form passivation solutions;

[0011] Under oxygen-free conditions, a sulfurized catalytic cracking gasoline hydrodesulfurization catalyst is added to a passivation solution and subjected to a passivation reaction. After the passivation reaction is completed, a passivated catalyst is obtained, which is a catalyst that can be directly exposed to air.

[0012] As a specific embodiment of the passivation method described above in this invention, the mass concentration of organic peroxides in the passivation solution is 0.5-20%, based on the total weight of the passivation solution being 100%.

[0013] As a specific embodiment of the passivation method described above in this invention, the passivation reaction can be carried out in one step or in steps. That is, the passivation solution can be a passivation solution of a single concentration, which is a one-step passivation, or the concentration of the passivation solution can be increased step by step to carry out step passivation. However, during the step passivation process, the mass concentration of organic peroxide in the passivation solution must still be maintained at 0.5-20%.

[0014] As a specific embodiment of the passivation method described above in this invention, the organic peroxide is an oil-soluble organic peroxide, including at least one of tert-butanol peroxide, tert-amyl peroxide, cyclohexanone peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, and diacetyl peroxide.

[0015] As a specific embodiment of the passivation method described above in this invention, the organic solvent includes at least one of ethanol, acetone, toluene, naphtha, and petroleum ether.

[0016] In the passivation method described above in this invention, the passivation reaction can be carried out in a batch reactor or a fixed-bed continuous reactor. As a specific embodiment of the passivation method described above in this invention, when using a batch reactor for passivation, the mass ratio of the passivation liquid to the sulfurized catalytic cracking gasoline hydrodesulfurization catalyst is 5:1-10:1; when using a fixed-bed continuous reactor for passivation, the mass hourly space velocity (MSV) of the passivation liquid during the passivation reaction is 5-15 h⁻¹. -1 .

[0017] As a specific embodiment of the passivation method described above in this invention, the passivation reaction can be carried out under constant temperature conditions or under variable temperature conditions. The temperature of the passivation reaction is 20-120℃, and the time is 0.1-2h.

[0018] In one specific embodiment of the passivation method described above in this invention, after the passivation reaction is completed, the passivation method further includes: filtering and washing with an organic solvent, then drying in a vacuum or inert atmosphere, and after drying, cooling to room temperature in a vacuum or inert atmosphere to obtain a passivated catalyst; or directly drying in an inert atmosphere, and after drying, cooling to room temperature in an inert atmosphere to obtain a passivated catalyst. In the passivation method described above in this invention, when the passivation reaction is carried out in a fixed-bed continuous reactor, after the passivation reaction is completed, the catalyst is directly dried in an inert atmosphere, and after drying, cooled to room temperature in an inert atmosphere to obtain a passivated catalyst. The purpose of drying is to remove the organic solvent adsorbed on the catalyst surface.

[0019] In one specific embodiment of the passivation method described above in this invention, the organic solvent used for washing includes at least one of acetone, toluene, naphtha, petroleum ether, and ethanol.

[0020] As a specific embodiment of the passivation method described above in this invention, the operating temperature of both filtration and washing is not higher than 50°C;

[0021] And / or the drying process is carried out at 50-150℃ for 0.5-2 hours.

[0022] In one specific embodiment of the passivation method described above in this invention, the inert atmosphere used in the drying process includes nitrogen or the like.

[0023] As a specific embodiment of the passivation method described above in this invention, the preparation method of the sulfurized catalytic cracking gasoline hydrodesulfurization catalyst includes:

[0024] The active metal precursor and the sulfur-containing compound were fully dissolved in an aqueous ammonia solution to obtain a sulfur-containing active metal precursor solution.

[0025] A catalyst support impregnated with an equal volume of sulfur-containing active metal precursor solution was obtained.

[0026] The catalyst support impregnated with the active component is frozen and then freeze-dried under vacuum to obtain an intermediate for dehydration and deammoniation.

[0027] The intermediate for dehydration and deammoniation is heat-treated in a vacuum or oxygen-free atmosphere, and then reduced in an H2-containing atmosphere to obtain the catalytic cracking gasoline hydrodesulfurization catalyst. Compared with existing catalysts, the metal active component in the catalytic cracking gasoline hydrodesulfurization catalyst provided by this invention has a higher dispersion on the catalyst support surface, and it can exhibit higher desulfurization activity and selectivity in the catalytic cracking gasoline hydrodesulfurization reaction.

[0028] In a specific embodiment of the passivation method described above in this invention, the active metal includes a first active metal and a second active metal, wherein the first active metal includes at least one of Group VIII metal elements and the second active metal includes at least one of Group VIB metal elements.

[0029] In a specific embodiment of the passivation method described above in this invention, the first active metal includes Co and / or Ni, and the second active metal includes Mo and / or W.

[0030] In a specific embodiment of the passivation method described above in this invention, the first active metal is Co and the second active metal is Mo.

[0031] In this invention, those skilled in the art can rationally select the specific substances of the active metal precursor based on the specific combination of active metals. For example, when the active metal includes Co, the cobalt precursor in the active metal precursor includes at least one of cobalt chloride, cobalt nitrate, and cobalt acetate; when the active metal includes Mo, the molybdenum precursor in the active metal precursor includes at least one of ammonium molybdate and molybdenum oxide.

[0032] As a specific embodiment of the passivation method described above in this invention, the mass loading of MoS2, based on metal sulfides, is 6-18%, preferably 10-16%, and the mass loading of CoS is 2-7%, preferably 3.5-5.5%, wherein the mass loadings are all calculated based on the total weight of the catalyst as 100%.

[0033] The mass loading of Ni and other Group VIII metal sulfides, as well as W and other Group VIB metal sulfides, can be reasonably adjusted according to the mass loading of CoS and MoS2, as long as the purpose of this invention can be achieved. For example, in some embodiments of this invention, when the first active metal is Ni or a combination of Co and Ni, and the second active metal is W or a combination of Mo and W, the mass loading of NiS or NiS and CoS, based on metal sulfides, is 2-7%, and the mass loading of WS2 or WS2 and MoS2 is 6-18%.

[0034] As a specific embodiment of the passivation method described above in this invention, the sulfur-containing compound includes one or two of ammonium sulfide and thiourea.

[0035] In a specific embodiment of the preparation method described above in this invention, the molar ratio of sulfur atoms in the sulfur-containing compound to metal atoms in the active metal precursor is 1.5:1-4:1, preferably 2:1-4:1.

[0036] As a specific embodiment of the passivation method described above in this invention, the catalyst support includes mesoporous alumina (i.e., alumina with a mesoporous structure, wherein the size of the mesopores is 2-50 nm), or a composite material containing both microporous molecular sieves and mesoporous alumina.

[0037] In one specific embodiment of the passivation method described above in this invention, the freezing temperature is -70 to 0°C, and the time is 4-48 hours.

[0038] The vacuum freeze-drying process involves a pressure of 0-40 Pa, a temperature of -100 to 0 °C, and a time of 12-48 h.

[0039] In the passivation method described above in this invention, the freezing involved in the preparation of the sulfurized catalytic cracking gasoline hydrodesulfurization catalyst includes direct freezing, vacuum evaporation freezing, or spray freezing; the vacuum freeze drying involved can be carried out in a vacuum freeze dryer.

[0040] In the passivation method described above in this invention, the heat treatment process involved in the preparation of the sulfurized catalytic cracking gasoline hydrodesulfurization catalyst can be carried out under constant temperature conditions or under variable temperature conditions; the oxygen-free atmosphere used in the heat treatment process can be a nitrogen atmosphere or a hydrogen atmosphere.

[0041] In one specific embodiment of the passivation method described above in this invention, the heat treatment temperature is 50-120°C and the time is 2-6 hours.

[0042] As a specific embodiment of the passivation method described above in this invention, the heat treatment includes first treating at 50-70℃ for 1-3 hours, and then raising the temperature to 80-120℃ for 1-3 hours.

[0043] In one specific embodiment of the passivation method described above in this invention, the reduction temperature is 250-350℃, preferably 280-320℃, and the time is 2-6h, preferably 2-4h.

[0044] In the passivation method described above in this invention, the H2 atmosphere used in the reduction process can be a pure H2 atmosphere or a mixed atmosphere of hydrogen and an inert gas. The inert gas can be, for example, nitrogen. Furthermore, this invention does not impose specific requirements on the concentration of hydrogen in the mixed atmosphere of hydrogen and inert gas, and the concentration of hydrogen can be adjusted according to the intensity of the reduction reaction.

[0045] Compared with existing preparation technologies for sulfurized hydrodesulfurization catalysts, the preparation method of the catalytic cracking gasoline hydrodesulfurization catalyst provided by the present invention first impregnates the catalyst support with an equal volume of sulfur-containing active metal precursor solution, then removes the water introduced during the impregnation process and the ammonia molecules introduced by the ammonia solution through freezing and vacuum freeze drying methods, then converts the metal components in situ into polysulfide metal salts, and finally reduces them in an H2 atmosphere to generate a sulfurized catalyst, namely the sulfurized catalytic cracking gasoline hydrodesulfurization catalyst.

[0046] Compared to the traditional high-temperature drying method used in catalyst preparation, this invention employs a freeze-drying method (freezing + vacuum freeze-drying) to remove moisture from the impregnated sample. During this process, moisture escapes from the support pores through sublimation, eliminating capillary forces between the liquid and solid phases. The metal precursor is deposited in situ on the surface of the support pores. Therefore, freeze-drying effectively confines the active metal components, significantly improving their dispersion within the support pores. This results in longer Mo2S active phase lamellar lengths and fewer stacked layers on the catalyst surface, leading to higher desulfurization activity and selectivity in the catalytic cracking of gasoline hydrodesulfurization. This overcomes the problem of uneven distribution of active components caused by migration during conventional high-temperature drying in traditional catalyst preparation, resulting in lower desulfurization activity and selectivity. Simultaneously, the freeze-drying method allows for the simultaneous removal of ammonia molecules from the active metal precursor solution during dehydration, preventing ammonia adsorption at acidic sites on the catalyst surface and thus avoiding deactivation. This results in a catalyst exhibiting even higher catalytic desulfurization activity.

[0047] The preparation method provided by this invention employs an "in-situ deposition and conversion of active metals" approach. First, an equal volume of sulfur-containing active metal precursor solution is impregnated onto the catalyst support, allowing the active metal precursor and sulfur-containing compound to be simultaneously loaded onto the catalyst support (surface and pores). Subsequently, after freezing and vacuum freeze-drying and activation, it is in-situ converted into a metal sulfide with high hydrodesulfurization activity. Compared to traditional in-vessel and out-of-vessel sulfidation technologies, the catalyst preparation process provided by this invention eliminates the need for drying, calcination, and sulfidation steps, reducing the interaction between the active metal component and the catalyst support, and significantly simplifying the process route.

[0048] On the other hand, the present invention also provides a passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, wherein the catalyst is obtained by the passivation method of the sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst described above, and an oxide layer / passivation layer is provided on the outer surface of its sulfur-type active center, wherein the oxide layer is formed by the reaction of organic peroxides with Mo-S bonds. This oxide layer is a thin and dense passivation layer formed by the reaction of organic peroxides with Mo-S bonds on the surface of the sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst (i.e., Mo-S bonds of metal sulfides located on the surface of the sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst), which can protect the internal sulfur-type metal components.

[0049] In another aspect, the present invention also provides the application of the passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst described above in the hydrodesulfurization of catalytic cracking gasoline.

[0050] Compared with the prior art, the beneficial technical effects achieved by the present invention include:

[0051] This invention uses oil-soluble organic peroxides to passivate sulfurized catalytic cracking gasoline hydrodesulfurization catalysts. During the passivation process, the oil-soluble organic peroxides generate highly reactive oxygen species such as superoxide radicals and peroxy radicals. These oxygen species have high oxidation activity at low temperatures (i.e., the passivation reaction temperature, which refers to 20-120℃), and can selectively passivate the edge sites of sulfurized active metal components. They react with the Mo-S bonds on the surface of the sulfurized catalytic cracking gasoline hydrodesulfurization catalyst to rapidly generate a thin and dense oxide layer / passivation layer, preventing the diffusion and reaction of the passivation liquid into the interior of the sulfurized metal active sites, thus isolating the internal active substances from O2. When in use, the passivation layer can be removed in an H2 atmosphere to completely restore the activity. Furthermore, the reduction products of the passivation layer (such as tert-butanol, tert-amyl alcohol, and cyclohexanone) are organic compounds, which are stable and do not contain elements harmful to oil products. Their adsorption on the catalyst surface will not have any adverse effect on the hydrodesulfurization reaction of catalytic cracking gasoline. Compared with existing gas-phase passivation and liquid-phase passivation, the passivation conditions of organic peroxides (concentration of passivation liquid, liquid-solid ratio, temperature, and time during the passivation process) are more controllable. This can minimize the destructive effect of the passivation process on the active centers of sulfide-state metals. It can also improve the dispersion of the active centers of sulfide-state metals during the passivation process, improve the lamellar length and stacking layer number of the Co-Mo-S active phase, and improve the hydrodesulfurization activity of the catalyst.

[0052] The rapid heat transfer between the passivation liquid and the catalyst liquid-solid two-phase system can avoid the problem of local hot spots appearing during the passivation process, which would lead to a deterioration in the passivation effect.

[0053] Furthermore, compared to water-soluble passivating agents, passivation treatment using oil-soluble organic peroxides has less impact on the surface of sulfide-state catalysts. Specifically, passivation treatment with water-soluble passivating agents causes partial dissolution and loss of metal components on the surface of sulfide-state catalysts, while the use of oil-soluble organic peroxides can avoid this problem, and the passivated catalyst exhibits better reaction performance. Detailed Implementation

[0054] It should be noted that the term "comprising" and any variations thereof in the specification and claims 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 that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] In this invention, unless otherwise specified, the term "two kinds" as used in this specification means "at least two kinds".

[0060] 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.

[0061] 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 appendices 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 apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0062] Example 1

[0063] This embodiment provides a passivated sulfurized catalytic cracking gasoline hydrodesulfurization catalyst, which is obtained by passivating the sulfurized catalytic cracking gasoline hydrodesulfurization catalyst with organic peroxides. The preparation process includes the following specific steps:

[0064] S1: Preparation of sulfurized catalytic cracking gasoline hydrodesulfurization catalyst:

[0065] S11: Preparation and loading of sulfur-containing active metal precursor solutions:

[0066] Add a 25% ammonia solution to 45g of a 40% ammonium sulfide aqueous solution and bring the volume to 50mL; then add 12.1g of ammonium heptamolybdate [(NH4)6Mo7O 24 The metal salt was stirred until completely dissolved, and then diluted to 65 mL with deionized water to obtain a sulfur-containing Co-Mo precursor solution, denoted as Co-Mo-S precursor solution.

[0067] Using clover-shaped strips of alumina (with a mesoporous structure) with a diameter of 2.2 mm, a length of 4-10 mm, and a water absorption rate of 65%, as a carrier, a sulfur-containing Co-Mo precursor solution was impregnated onto 100 g of alumina carrier using an equal-volume impregnation method, so that the catalyst carrier could fully absorb the sulfur-containing Co-Mo precursor solution.

[0068] S12: Vacuum freeze-drying and catalyst activation:

[0069] The catalyst support impregnated with the Co-Mo-S precursor solution was frozen at -30°C for 6 hours, and then placed in a vacuum freeze dryer. The vacuum was reduced to below 20 Pa and dried at -30°C for 30 hours to obtain dehydrated and deammoniated Co-Mo-S / Al2O3.

[0070] The dehydrated and deammonened Co-Mo-S / Al2O3 was heat-treated at 65°C for 2 hours in H2 atmosphere to generate polysulfide metal salts. The salts were then reduced by heating to 300°C for 2 hours to obtain the sulfidated catalyst, i.e., the sulfidated catalytic cracking gasoline hydrodesulfurization catalyst.

[0071] S2: Passivation treatment of sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst:

[0072] The sulfurized catalytic cracking gasoline hydrodesulfurization catalyst obtained in S1 was transferred to a petroleum ether solution of cyclohexanone peroxide in a glove box for passivation. The passivation reaction conditions were: temperature 50°C, time 1 h, mass concentration of cyclohexanone peroxide petroleum ether solution 5%, and mass ratio of passivation solution to sulfurized catalytic cracking gasoline hydrodesulfurization catalyst 10:1. After passivation, the catalyst was filtered at room temperature and washed with petroleum ether, then dried under vacuum at 90°C for 2 h. After drying, it was cooled to room temperature in a N2 atmosphere to obtain the passivated sulfurized catalytic cracking gasoline hydrodesulfurization catalyst, denoted as Catalyst-1. The mass loading of CoS was 4% and the mass loading of MoS2 was 11% based on metal sulfides, where the loadings were calculated based on 100% of the total catalyst weight.

[0073] Example 2

[0074] This embodiment provides a passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, the only difference between its preparation method and the catalyst provided in Example 1 is that:

[0075] In S12, the vacuum low-temperature drying pressure is 40Pa, the temperature is -20℃, and the treatment time is 48h.

[0076] The dehydrated and deammonened Co-Mo-S / Al2O3 was heat-treated at 75°C for 2 hours in a H2 / N2 mixed gas (H2 volume concentration of 10%) to generate polysulfide metal salts, and then reduced to sulfide catalyst by heating to 300°C for 2 hours in an H2 atmosphere.

[0077] The passivated sulfurized catalytic cracking gasoline hydrodesulfurization catalyst obtained in this embodiment is designated as Catalyst-2.

[0078] Example 3

[0079] This embodiment provides a passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, the only difference between its preparation method and the catalyst provided in Example 1 is that:

[0080] In S12, the catalyst support impregnated with the Co-Mo-S precursor solution was frozen at -40℃, vacuum low-temperature drying pressure was 40Pa, temperature was -40℃, and treatment time was 16h.

[0081] Dehydrated and deammoniated Co-Mo-S / Al2O3 was heat-treated at 100℃ for 2 hours in a H2 / N2 mixed gas (H2 volume concentration of 10%) to generate polysulfide metal salts, and then reduced to sulfide catalyst by heating to 320℃ for 4 hours in an H2 atmosphere.

[0082] The passivation reaction conditions were as follows: passivation was carried out in a fixed-bed continuous reactor at a temperature of 110°C for 15 minutes; the passivation solution, i.e., a petroleum ether solution of cyclohexanone peroxide, had a mass concentration of 18%; and the mass hourly space velocity (MSV) of the passivation solution during the passivation process was 10 h⁻¹. -1 After passivation, the sample was dried directly in a nitrogen atmosphere at 90°C for 2 hours, and then cooled to room temperature in a N2 atmosphere.

[0083] The passivated sulfurized catalytic cracking gasoline hydrodesulfurization catalyst obtained in this embodiment is designated as Catalyst-3.

[0084] Example 4

[0085] This embodiment provides a passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, the only difference between its preparation method and the catalyst provided in Example 1 is that:

[0086] In S2, the sulfided catalyst obtained in S1 was transferred to an ethanol solution of tert-butanol peroxide in a glove box for passivation. After passivation, it was filtered at room temperature and washed with ethanol, and then dried under vacuum at 100°C for 2 hours. After drying, it was cooled to room temperature in N2 atmosphere to obtain the passivated sulfided catalytic cracking gasoline hydrodesulfurization catalyst, denoted as Catalyst-4.

[0087] The passivation reaction conditions were as follows: first, passivation was performed at 20℃ for 20 min, then the temperature was increased to 60℃ at a rate of 2℃ / min, which also served as passivation for 20 min, and finally, passivation was performed again at 60℃ for 20 min, with a total passivation time of 1 h. The mass concentration of the tert-butanol peroxide solution was 10%, and the mass ratio of the passivation solution to the sulfidated catalyst was 5:1.

[0088] Example 5

[0089] This embodiment provides a passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, the only difference between its preparation method and the catalyst provided in Example 1 is that:

[0090] In S2, the sulfurized catalyst obtained in S1 is transferred to a fixed-bed continuous reactor in a glove box for passivation. After passivation, it is dried at 100°C for 2 hours in a nitrogen atmosphere. After drying, it is cooled to room temperature in a N2 atmosphere to obtain the passivated sulfurized catalytic cracking gasoline hydrodesulfurization catalyst, denoted as Catalyst-5.

[0091] The passivation reaction conditions were as follows: the passivation solution used was a petroleum ether solution of cyclohexanone peroxide with a mass concentration of 5%, and the mass hourly space velocity (HHSV) of the passivation solution during the passivation process was 10 h⁻¹. -1 The passivation temperature was 50℃ and the time was 1 hour.

[0092] Example 6

[0093] This embodiment provides a passivated sulfurized catalytic cracking gasoline hydrodesulfurization catalyst, which is obtained by passivating the sulfurized catalytic cracking gasoline hydrodesulfurization catalyst with organic peroxides. The preparation process includes the following specific steps:

[0094] S1: Preparation of sulfurized catalytic cracking gasoline hydrodesulfurization catalyst:

[0095] S11: Preparation and loading of sulfur-containing active metal precursor solutions:

[0096] Add a 25% ammonia solution to 45g of a 40% ammonium sulfide aqueous solution and bring the volume to 55mL; then add 17.64g of ammonium heptamolybdate [(NH4)6Mo7O 24 The metal salt was stirred with 13.7 g of cobalt nitrate hexahydrate [(CH3COO)2Co·4H2O] until completely dissolved, and then diluted to 75 mL with deionized water to obtain a sulfur-containing Co-Mo precursor solution, denoted as Co-Mo-S precursor solution.

[0097] Using clover-shaped strips of alumina (with a mesoporous structure) with a diameter of 3.2 mm, a length of 4-12 mm, and a water absorption rate of 75% as a carrier, a sulfur-containing Co-Mo precursor solution was impregnated onto 100 g of alumina carrier using an equal-volume impregnation method, so that the catalyst carrier could fully absorb the sulfur-containing Co-Mo precursor solution.

[0098] S12: Vacuum freeze-drying and catalyst activation:

[0099] The catalyst support impregnated with the Co-Mo-S precursor solution was frozen at -30°C for 12 hours, and then placed in a vacuum freeze dryer. The vacuum was reduced to below 20 Pa and dried at -30°C for 12 hours to obtain dehydrated and deammoniated Co-Mo-S / Al2O3.

[0100] The dehydrated and deammonened Co-Mo-S / Al2O3 was heat-treated at 55°C for 6 hours in H2 atmosphere to generate polysulfide metal salts. The salts were then reduced by heating to 320°C for 2 hours to obtain the sulfidated catalyst, which is the sulfidated catalytic cracking gasoline hydrodesulfurization catalyst.

[0101] S2: Passivation treatment of sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst:

[0102] The sulfide-form catalyst obtained in S1 was transferred to a fixed-bed continuous reactor in a glove box for passivation. The passivation solution used was a petroleum ether solution of cyclohexanone peroxide with a mass concentration of 2%, and the mass hourly space velocity (WHSV) of the passivation solution was 10 h⁻¹. -1 The passivation temperature was 50℃ for 2 hours. After passivation, the catalyst was dried in a nitrogen atmosphere at 60℃ for 2 hours. After drying, it was cooled to room temperature in a N2 atmosphere to obtain a passivated sulfurized catalytic cracking gasoline hydrodesulfurization catalyst, denoted as Catalyst-6. The mass loading of CoS was 5% and the mass loading of MoS2 was 16% based on metal sulfides. All loadings were calculated based on 100% of the total catalyst weight.

[0103] Example 7

[0104] This embodiment provides a passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, the only difference between its preparation method and the catalyst preparation method provided in Example 6 is:

[0105] In step S2, the sulfide-form catalyst obtained in step S1 is transferred to a fixed-bed continuous reactor in a glove box and passivated using an ethanol solution of diacetyl peroxide as the passivation solution. The mass concentration of diacetyl peroxide in the passivation solution is 1.5%, and the mass hourly space velocity (WHSV) of the passivation solution is 15 h⁻¹. -1 The passivation temperature was 35℃ and the time was 1h. After passivation, the catalyst was dried at 60℃ for 2h in a nitrogen atmosphere. After drying, it was cooled to room temperature in a N2 atmosphere to obtain the passivated sulfurized catalytic cracking gasoline hydrodesulfurization catalyst, denoted as Catalyst-7.

[0106] Comparative Example 1

[0107] This comparative example provides a passivated sulfurized catalytic cracking gasoline hydrodesulfurization catalyst. The process involves first loading an active metal salt onto a support using an impregnation method, followed by drying and calcination to obtain an oxidized catalyst. Then, the oxidized catalyst undergoes in-vessel sulfurization to obtain a sulfurized catalyst. Finally, a gas-phase passivation technique is used to passivate the sulfurized catalyst under varying O2 concentration conditions. The specific steps involved in its preparation are shown below:

[0108] (1) Preparation of sulfide catalyst:

[0109] 12.1g of ammonium heptamolybdate [(NH4)6Mo7O 24 12.8 g of cobalt nitrate hexahydrate [Co(NO3)2·6H2O] and 12.8 g of cobalt nitrate hexahydrate [Co(NO3)2·6H2O] were dissolved in 50 mL of ammonia water with a mass concentration of 25%, and the volume was adjusted to 65 mL with deionized water to obtain the active component impregnation solution.

[0110] Using a clover-shaped strip of alumina (with a mesoporous structure) with a diameter of 2.2 mm, a length of 4-10 mm, and a water absorption rate of 65%, as a carrier, the active component impregnation liquid is impregnated onto 100 g of alumina carrier in an equal volume, allowing the catalyst carrier to fully absorb the active component impregnation liquid. Then, it is dried at 120 °C for 4 h and calcined at 520 °C for 6 h to obtain an oxidized catalyst.

[0111] A mixture of H2S and H2 gas was introduced into the oxidized catalyst to carry out a sulfidation reaction. The sulfidation reaction conditions were: temperature 370℃, time 4 h, H2S volume concentration 5%, and volume hourly space velocity (VHSV) 1000 h⁻¹. -1 After the sulfidation reaction is completed, the product is cooled to room temperature in a N2 atmosphere to obtain a sulfidated catalyst. The mass loading of CoS is 4% and the mass loading of MoS2 is 11% based on metal sulfides. The loadings are calculated based on the total weight of the catalyst as 100%.

[0112] (2) Passivation of sulfide catalysts:

[0113] An O2 / N2 mixture was introduced into the sulfided catalyst obtained in step (1), and the O2 concentration in the passivation gas was adjusted. The passivation was carried out for 10 min at an O2 volume concentration of 1%, for 5 min at an O2 concentration of 5%, and for 5 min at an O2 concentration of 15%. Other passivation reaction conditions included: an initial passivation temperature of 50°C, a total duration of 20 min, and a volume hourly space velocity of 1000 h⁻¹. -1 Finally, N2 was introduced to cool the catalyst to room temperature, yielding a passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, denoted as Reference-1.

[0114] Comparative Example 2

[0115] This comparative example provides a passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst. The difference between its preparation method and that of the catalyst provided in Comparative Example 1 lies only in the passivation process of the sulfur-type catalyst. This comparative example uses paraffin wax with a melting point of 57-58℃ and employs liquid-phase passivation technology to passivate the sulfur-type catalyst. The specific steps of the passivation treatment are as follows:

[0116] After sulfidation, the reactor inlet temperature is lowered to 100°C, and liquid paraffin for dehydration and aromatic removal is introduced into the reactor (1 kg of liquid paraffin is introduced per kilogram of catalyst per hour). After about 30 minutes, the liquid paraffin penetrates the catalyst bed and continues to passivate for another 30 minutes, so that the paraffin forms a uniform and uniform protective film on the catalyst surface to prevent the catalyst from reacting with O2 in the air. Then, it is cooled to room temperature in a N2 atmosphere to obtain a passivated sulfidation-type catalytic cracking gasoline hydrodesulfurization catalyst, denoted as Reference-2.

[0117] Comparative Example 3

[0118] This comparative example provides a passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst. The difference between its preparation method and that of the catalyst provided in Comparative Example 1 lies only in the passivation process of the sulfur-type catalyst. This comparative example uses oil-soluble cyclohexanone peroxide as a passivating agent to passivate the sulfur-type catalyst. The specific steps of the passivation treatment are as follows:

[0119] The sulfided catalyst was transferred to a petroleum ether solution of cyclohexanone peroxide in a glove box for passivation for 1 hour, then filtered and washed with petroleum ether. The passivation conditions were: temperature 50℃, mass concentration of cyclohexanone peroxide solution 5%, and mass ratio of passivation solution to sulfided catalyst 10:1. The passivated catalyst was dried under vacuum at 90℃ for 2 hours, and then cooled to room temperature in a N2 atmosphere to obtain the passivated catalytic cracking gasoline hydrodesulfurization catalyst Reference-3.

[0120] Comparative Example 4

[0121] This comparative example provides a passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, the only difference between its preparation method and the catalyst provided in Example 1 is that:

[0122] In S2, gas-phase passivation technology is used to passivate the sulfide-state catalyst under varying O2 concentration conditions. The specific passivation steps are as follows:

[0123] An O2 / N2 mixture was introduced into the sulfided catalyst, and the O2 concentration in the passivation gas was adjusted. The passivation process was carried out for 10 min at an O2 volume concentration of 1%, for 5 min at an O2 concentration of 5%, and for 5 min at an O2 concentration of 15%. Other passivation reaction conditions included: an initial passivation temperature of 10℃, a total duration of 20 min, and a volume hourly space velocity of 1000 h⁻¹. -1 Finally, N2 was introduced to cool the catalyst to room temperature, yielding a passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, denoted as Reference-4.

[0124] Test Example 1

[0125] In this test example, the degree of sulfidation α, the average wafer length and the average number of stacked layers of the surface MoS2 sheets of Catalyst-1 to Catalyst-7 and Reference-1 to Reference-4 were measured, and the above catalysts were subjected to autothermal analysis.

[0126] The method for determining the degree of sulfidation α includes: first, using the "combustion-neutralization titration method" to determine the sulfur content on the surface of the catalyst to be tested, and then calculating the degree of sulfidation α of the catalyst to be tested based on the ratio of the actual sulfur content to the theoretical sulfur content.

[0127] The methods for determining the average length and average number of stacked layers of MoS2 sheets include: observing the morphology of MoS2 sheets on the surface of the sulfide catalyst using high-resolution transmission electron microscopy, taking at least 20 images for each sample; and determining the length and number of stacked layers of MoS2 sheets by statistically analyzing the parameters of 200-300 sheets for each sample.

[0128] Self-heating analysis includes: introducing air into the above-mentioned passivated catalysts at an initial temperature of 30°C to perform self-heating analysis, and using the highest self-heating temperature to characterize the passivation effect of different passivation technologies.

[0129] The sulfidation degree, average wafer length of surface MoS2, average number of lamellar layers, and highest self-heating temperature of the passivated catalyst obtained in this test example are shown in Table 1 below.

[0130] Table 1

[0131]

[0132] As shown in Table 1, the average MoS2 wafer length in the Reference-1 to Reference-3 catalysts obtained by sulfiding the oxidized catalyst using H2S in-reactor sulfidation technology in Comparative Examples 1 to 3 was 3.9-4.3 nm, and the average number of layers was 3.9-4.2. In contrast, the average wafer length of the catalysts prepared by the "freeze-drying-in-situ conversion" method in Comparative Example 4 and Examples 1 to 7 of this invention was greater than 5.7 nm, and the average number of layers was no greater than 3.5. This demonstrates that the freeze-drying method provided by this invention achieves high dispersion of the metal components and sulfur-containing compounds on the support surface during the drying process, ultimately forming a highly dispersed sulfide-state metal active phase. Furthermore, since the loading of the metal components and the formation of sulfides did not involve a high-temperature calcination step, the interaction between the metal components and the catalyst support was weak, thereby promoting the increase in MoS2 wafer length and dispersion on the support surface.

[0133] Table 1 also shows that, in preventing the loss of sulfur from the surface of the sulfided catalyst, the sulfidation degree of catalysts Reference-1, Reference-2, and Reference-4, which were passed through conventional O2 gas-phase passivation and paraffin liquid-phase passivation, was significantly lower than that of the catalysts obtained by controlled passivation treatment using organic peroxides as passivating agents in the embodiments of this invention. This indicates that controlled passivation using organic peroxides can effectively prevent the reaction between the sulfided metal on the catalyst surface and O2 in the air. Regarding the self-heating index of the catalyst, the highest self-heating temperature of Reference-1 catalyst obtained by gas-phase O2 passivation was 34.6℃, the highest self-heating temperature of Reference-4 catalyst was 33.9℃, and the highest self-heating temperature of Reference-2 catalyst obtained by liquid-phase paraffin passivation was 33.7℃, all higher than the self-heating effect of the catalysts obtained by controlled passivation treatment using organic peroxides as passivating agents in the embodiments of this invention. Therefore, the controlled passivation technology using organic peroxides in the embodiments of this invention makes the storage of sulfided catalysts convenient and safe, while maintaining a high degree of sulfidation.

[0134] Test Example 2

[0135] In this test example, Catalyst-1 to Catalyst-7 and Reference-1 to Reference-4 were respectively loaded into 20 mL fixed-bed adiabatic reactors for reaction performance evaluation, including:

[0136] The passivated catalysts were pretreated in a H2 atmosphere at 300°C for 2 h, and then the conditions were adjusted to the full-fraction catalytic cracking gasoline hydrotreating process conditions for reaction. The reaction conditions were: reactor temperature 260°C, reaction pressure 1.5 MPa, and volume hourly space velocity 3.0 h⁻¹. -1 The hydrogen-to-oil volume ratio was 260; samples were taken for analysis after 48 hours of reaction.

[0137] The catalytic performance data of the passivated catalyst obtained in this test example in the hydrodesulfurization reaction of catalytic cracking gasoline are shown in Table 2 below.

[0138] Table 2

[0139] catalyst Desulfurization rate / % Olefin decrease / ℃ Octane number loss / unit Catalyst-1 88.6 2.6 0.7 Catalyst-2 86.4 2.1 0.6 Catalyst-3 86.1 2.2 0.6 Catalyst-4 82.0 2.2 0.6 Catalyst-5 87.2 2.0 0.5 Catalyst-6 87.1 1.9 0.5 Catalyst-7 85.6 2.3 0.6 Reference-1 76.2 4.2 2.1 Reference-2 72.9 3.9 1.9 Reference-3 78.4 3.6 1.8 Reference-4 81.1 3.5 1.6

[0140] As can be seen from Table 2, compared with the comparative examples Reference-1 to Reference-4, the passivated catalysts Catalyst-1 to Catalyst-7 provided in the embodiments of the present invention have higher desulfurization rates, as well as lower olefin reduction and octane number loss. This indicates that the passivated catalysts provided in the embodiments of the present invention have higher desulfurization efficiency.

[0141] 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 passivation method for a sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, characterized in that, The passivation method includes: Organic peroxides are dissolved in organic solvents to form passivation solutions; Under oxygen-free conditions, a sulfurized catalytic cracking gasoline hydrodesulfurization catalyst is added to a passivation solution and subjected to a passivation reaction. After the passivation reaction is completed, a passivated catalyst is obtained.

2. The passivation method according to claim 1, characterized in that, Based on the total weight of the passivation solution as 100%, the mass concentration of organic peroxides in the passivation solution is 0.5-20%.

3. The passivation method according to claim 1 or 2, characterized in that, The organic peroxides include at least one of tert-butanol peroxide, tert-amyl peroxide, cyclohexanone peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, and diacetyl peroxide.

4. The passivation method according to claim 1 or 2, characterized in that, The organic solvent includes at least one of ethanol, acetone, toluene, naphtha, and petroleum ether.

5. The passivation method according to claim 1 or 2, characterized in that, The mass ratio of passivation fluid to sulfurized catalytic cracking gasoline hydrodesulfurization catalyst is 5:1-10:1, or the mass hourly space velocity (MSV) of the passivation fluid during the passivation reaction is 5-15 h⁻¹. -1 .

6. The passivation method according to claim 1 or 2, characterized in that, The passivation reaction is carried out at a temperature of 20-120℃ for a time of 0.1-2 hours.

7. The passivation method according to claim 1 or 2, characterized in that, After the passivation reaction is completed, the passivation method further includes: filtering and washing with an organic solvent, then drying in a vacuum or inert atmosphere, and after drying, cooling to room temperature in a vacuum or inert atmosphere to obtain a passivated catalyst; or directly drying in an inert atmosphere, and after drying, cooling to room temperature in an inert atmosphere to obtain a passivated catalyst.

8. The passivation method according to claim 7, characterized in that, The operating temperature for both filtration and washing should not exceed 50℃; And / or the drying process is carried out at 50-150℃ for 0.5-2 hours.

9. The passivation method according to claim 1 or 2, characterized in that, The preparation method of the sulfurized catalytic cracking gasoline hydrodesulfurization catalyst includes: The active metal precursor and the sulfur-containing compound were fully dissolved in an aqueous ammonia solution to obtain a sulfur-containing active metal precursor solution. A catalyst support impregnated with an active component was obtained by impregnating the catalyst support with an equal volume of sulfur-containing active metal precursor solution. The catalyst support impregnated with the active component is frozen and then freeze-dried under vacuum to obtain an intermediate for dehydration and deammoniation. The intermediate for dehydration and deammoniation is heat-treated in a vacuum or oxygen-free atmosphere and then reduced in an H2-containing atmosphere to obtain the catalytic cracking gasoline hydrodesulfurization catalyst.

10. The passivation method according to claim 9, characterized in that, The active metal includes a first active metal and a second active metal, wherein the first active metal includes at least one of Group VIII metal elements and the second active metal includes at least one of Group VIB metal elements.

11. The passivation method according to claim 9, characterized in that, The mass loading of MoS2 is 6-18% and the mass loading of CoS is 2-7% based on metal sulfides. The mass loadings are calculated based on the total weight of the catalyst as 100%.

12. The passivation method according to claim 9, characterized in that, The sulfur-containing compound includes one or both of ammonium sulfide and thiourea.

13. The passivation method according to claim 9, characterized in that, The freezing temperature is -70 to 0°C, and the time is 4-48 hours; The vacuum freeze-drying process involves a pressure of 0-40 Pa, a temperature of -100 to 0 °C, and a time of 12-48 h.

14. A passivated sulfur-type catalytic cracking gasoline hydrodesulfurization catalyst, characterized in that, The catalyst is obtained by the passivation method of the sulfurized catalytic cracking gasoline hydrodesulfurization catalyst according to any one of claims 1-13, wherein an oxide layer is provided on the outer surface of the sulfurized active center, wherein the oxide layer is formed by the reaction of organic peroxide with Mo-S bond.

15. The application of the passivated sulfurized catalytic cracking gasoline hydrodesulfurization catalyst of claim 14 in the hydrodesulfurization of catalytic cracking gasoline.

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