A process for the hydrofining of catalytically cracked gasoline

Abstract

The application discloses a catalytic cracking gasoline hydrofining method, which comprises the following steps: loading a pre-sulfided hydrofining catalyst into a fixed bed reactor, sulfidizing the hydrofining catalyst, mixing and preheating catalytic cracking gasoline and hydrogen, and then feeding the mixture into the fixed bed reactor to react, wherein the reaction conditions are as follows: the reaction temperature is 240-360 DEG C, the reaction pressure is 1.5-4.0 MPa, the space velocity is 0.5-4 h-1, and the hydrogen / oil volume ratio is 100-600:1. ‑1 The preparation method of the hydrofining catalyst is as follows: performing atomization and spraying treatment on a carrier by using a pre-spraying solution, aging after the spraying is completed to obtain a pretreated carrier, wherein the pre-spraying solution is a citric acid aqueous solution or a potassium hydroxide solution; impregnating the pretreated carrier with an impregnation solution containing an active component, and then aging, drying and calcining to obtain the hydrofining catalyst.

Description

Technical Field

[0001] This invention belongs to the field of petroleum hydrorefining technology, specifically relating to a method for hydrorefining catalytic cracking gasoline. Background Technology

[0002] Aromatics, as a basic chemical raw material, hold an important position. Their production technology and level are one of the indicators of a country's petrochemical development level. Global demand for aromatics is constantly increasing, especially for benzene and xylene, where demand is growing even faster. my country's aromatics production cannot meet this demand. Currently, the main source of aromatics is the extraction and separation of cracked gasoline, a byproduct of catalytic reforming gasoline and ethylene plants. Therefore, broadening the sources of aromatics extraction feedstock is of great significance for improving my country's self-sufficiency in the aromatics market and reducing dependence on foreign markets.

[0003] Catalytic cracking is a technology developed based on catalytic cracking, which produces propylene from heavy feedstock. Through process adjustments, catalytic cracking can produce gasoline with high aromatic content as feedstock for aromatics production. However, aromatics products have very strict requirements regarding impurities such as sulfur and nitrogen. Therefore, before aromatics extraction, catalytic cracked gasoline needs to be saturated with olefins and impurities such as sulfur and nitrogen removed.

[0004] Catalytic cracking technology emerged relatively late, and patent literature on hydrogenation catalysts and hydrotreating processes for catalytic cracking gasoline is scarce. Hydrotreating technology centered on hydrogenation catalysts for cracked gasoline (a byproduct of steam cracking to ethylene production) is an important branch of the hydrotreating field and can provide a reference for catalytic cracking gasoline hydrotreating technology. However, there are still some differences between catalytic cracking gasoline and steam cracking gasoline, mainly in that catalytic cracking gasoline has higher nitrogen, sulfur, and diene content, and its components are relatively heavier. The feedstock used in steam thermal cracking processes is lighter (mostly naphtha), resulting in relatively low sulfur content and virtually no nitrogen in steam cracking gasoline; the feedstock used in catalytic cracking processes is heavier (wax oil or residue oil), leading to higher sulfur and nitrogen content in the catalytic cracking process. Therefore, the lower quality of catalytic cracking gasoline places higher demands on hydrorefining catalysts. The hydrorefining process for catalytic cracking gasoline aimed at producing aromatics extraction feedstock needs to solve two key problems: first, the catalyst must have low aromatics saturation activity under high desulfurization, denitrification, and olefin saturation activity; second, higher requirements are placed on the catalyst's anti-coking performance to ensure long-term stable operation of the unit.

[0005] Hydrorefining catalysts are classified into supported and unsupported types, with supported catalysts being more prevalent in industrial applications. Supported hydrorefining catalysts are typically prepared by impregnating an active metal (Mo, W, Ni, Co, etc.) onto a support. The active component of the catalyst prepared by this impregnation method is distributed on the inner and outer surfaces of the catalyst support, including the inner surfaces of deep pores and voids. Numerous reports have been published on the preparation methods of hydrorefining catalysts, mainly focusing on preparation methods and processes, support modification, and the addition of auxiliary agents.

[0006] Conventional methods produce hydrorefining catalysts with active metals in an oxidized state, while the actual catalytically active component is in a sulfidated state. Therefore, the catalyst must undergo sulfidation activation before use, a process known as pre-sulfidation. Pre-sulfidation significantly impacts catalyst performance and is a crucial pretreatment step. Based on the sulfur loading method, pre-sulfidation methods can be categorized into in-vessel pre-sulfidation and external pre-sulfidation.

[0007] In-reactor pre-sulfurization technology involves loading the catalyst into the reactor before sulfidation. The hydrogen sulfide required for the reaction is usually produced by decomposing a sulfiding agent, and industrially, dimethyl disulfide (hereinafter referred to as DMDS) is commonly used. The main sulfidation steps are as follows: under hot hydrogen circulation (reactor inlet temperature reaches 180℃), DMDS is gradually injected into the system, then decomposes with hydrogen to release hydrogen sulfide gas, which then reacts with the oxidized catalyst in the reactor to finally obtain the sulfided catalyst. This method has three main problems: (1) the sulfiding agent used is toxic and harmful, and easily causes environmental pollution; (2) the equipment needs to be equipped with sulfidation facilities and supporting pipelines that are only used during operation; (3) the equipment poses safety and environmental hazards during the sulfidation process due to high temperature, high pressure, and high H2S concentration.

[0008] Therefore, the external pre-sulfurization method has emerged. The advantages of external pre-sulfurization technology are: (1) External pre-sulfurization technology improves the utilization rate of active metal components of hydrogenation catalyst and makes the catalyst more fully sulfided; (2) External pre-sulfurization technology can save start-up time and make the start-up process more convenient; (3) The start-up site of external pre-sulfurization catalyst avoids the use of toxic sulfides and does not require the installation of special sulfidation facilities.

[0009] Patent CN 112337488 A discloses a nickel sulfide-based hydrogenation catalyst and a method for hydrogenating pyrolysis gasoline. Nickel is the main active metal, copper and / or molybdenum are co-active metals, and magnesium-aluminum composite oxide is the dispersion medium. The method includes a first-stage nickel sulfide-based hydrogenation catalyst and a second-stage nickel sulfide-based hydrogenation catalyst. The method involves: firstly, loading the first-stage and second-stage nickel sulfide-based hydrogenation catalysts into two series-connected fixed-bed hydrogenation reactors with built-in microporous dispersion components; purging the reactors and pipelines with nitrogen; then mixing preheated hydrotreated naphtha with hydrogen and introducing the mixture into the fixed-bed hydrogenation reactors; simultaneously raising the temperature to the reaction conditions; and finally switching to pyrolysis gasoline for the hydrogenation reaction.

[0010] The catalytic cracking gasoline hydrorefining method described in patent CN1109495A involves connecting two pre-sulfurized non-precious metal catalysts with different activities and particle diameters in series, either separately in one reactor or in two separate reactors, and operating at a reaction temperature of 150–300°C, a hydrogen partial pressure of 1.2–8.0 MPa, and a volume hourly space velocity of 4–20 h⁻¹. -1 and 1 to 15 hours -1 Volumetric hydrogen-to-oil ratio 150–500 nm 3 / m 3 The hydrogenation reaction is carried out under operating conditions where the weight ratio of recycled oil to fresh feedstock is 0.5–5:1. The diene value of the hydrogenated product is less than 1 gI₂ / 100 g, and the octane number loss is no more than 3 units. The hydrogenated product is used as a gasoline blending component. The hydrogenated product of this invention is used as a feedstock for aromatics extraction.

[0011] Patent ZL 200610064905.0 relates to a hydrorefining catalyst, its preparation method, and its application. The catalyst uses molybdenum, cobalt, and nickel as active components. Based on 100% of the total catalyst weight, it contains 14-20% molybdenum oxide, 1-6% cobalt oxide, and 1-4% nickel oxide. The content of alkali metal oxides in the additives is 1-3%, the content of P and / or Sb oxides in the additives is 1-5%, and the content of Si and / or tin oxides in the additives is 2-6%. This catalyst can be used for the hydrorefining of C5-C8 and C6-C8 distillate oils, and can adapt to oils with varying sulfur content and high space velocities. However, the patent does not describe the catalyst's denitrification performance or its desulfurization performance under high nitrogen content conditions.

[0012] The literature "Industrial Application of DCC Gasoline Full-Fraction Selective Hydrodesulfurization Technology (CDOS-FRCNⅡ)" introduces the advantages of a gasoline full-fraction selective hydrodesulfurization process for producing ultra-low sulfur gasoline. This process eliminates the need for catalytic cracking of gasoline light and heavy fractions (LCN / HCN), and features a simple process, flexible operation, and low investment. The novel nano-titanium-based catalyst used in this process exhibits high desulfurization activity, high selectivity, and stability, making it suitable for full-fraction hydrodesulfurization processes. It demonstrates excellent activity and stability in processing FCC gasoline and DCC gasoline with high diene and high olefin content. However, a three-bed reactor is required to achieve the desired results. Specific process conditions are shown in the table below:

[0013] project actual value <![CDATA[Space velocity per hour -1 > 2.5 <![CDATA[Feed rate / t·h -1 > 63 Inlet temperature / °C 152 Second reaction inlet temperature / ℃ 281.5 Three-phase inlet temperature / ℃ 355.8 Pressure / MPa 1.63～1.66

[0014] ZL 200810010245.7 discloses a method for pre-sulfurizing a hydrogenation catalyst and a start-up method for a hydrogenation process. During the catalyst pre-sulfurization process, the amount of sulfiding agent introduced into the pre-sulfurized portion of the catalyst is significantly higher than the theoretical sulfur requirement of the active hydrogenation metal in the catalyst. The pre-sulfurized hydrogenation catalyst is mixed with or layered with the unpre-sulfurized hydrogenation catalyst in the reactor for start-up activation; however, this operation may result in uneven distribution of the active sulfidated phase in the catalyst.

[0015] CN 104646034 A discloses a method for preparing a sulfide-type hydrorefining catalyst. The method involves impregnating a support with an impregnation solution, followed by in-situ crystallization and heat treatment to obtain the sulfide-type hydrorefining catalyst. The impregnation solution is characterized by containing active metals such as ammonium molybdate and / or ammonium tungstate, inorganic salt precursors of Ni and / or Co, and also contains a sulfiding agent, an organic complexing agent, and a co-solvent.

[0016] Patent ZL 200710012674.3 describes a start-up method for gasoline hydrorefining. This method involves pre-sulfurizing the hydrodesulfurization catalyst at specific sulfidation temperatures and times, then switching the feedstock, and directly adjusting the process parameters to conventional reaction conditions for selective hydrodesulfurization of gasoline. The drawback of this method is the long stabilization time after feedstock switching. In a specific embodiment of this patent, the stabilization time on a small evaluation device reached 100 hours, resulting in low efficiency in terms of experimental time. More importantly, it is well known that the poor product quality caused by unstable catalyst activity during the initial start-up of large industrial plants can impose significant economic pressure on enterprises.

[0017] Introducing promoters into catalysts is one of the most common methods to improve the activity of hydrogenation catalysts. Commonly used promoters for hydrorefining catalysts include primary promoters such as metals like cobalt and nickel, and secondary promoters such as non-metals like phosphorus and boron. Meanwhile, chelating agents, such as citric acid, phosphoric acid, ethylenediamine, ethylenediaminetetraacetic acid, and ethylene glycol, which are used as complexing components in the preparation of active component solutions, have also achieved good results in the preparation of hydrorefining catalysts.

[0018] Patent ZL201510700293.9 relates to a hydrogenation catalyst and its preparation method. The preparation method includes: (1) loading a water-soluble salt of a hydrogenation metal active component and an organic complexing agent onto a support using an impregnation method, wherein the carbon content in the semi-finished catalyst is 0.03-0.5% by weight; (2) impregnating the semi-finished catalyst obtained in step (1) with a solution containing an organic complexing agent as an impregnation liquid, and then drying it without calcination; (3) loading a metal element as an auxiliary agent onto the support; wherein step (3) is performed before, during, and after step (1) and before step (2) in any one or more of these steps. This patent uses a three-step impregnation method to prepare the catalyst, which consumes a lot of manpower and resources, resulting in a significant increase in the cost of catalyst preparation.

[0019] ZL91110935.8 discloses a method for preparing a cobalt-molybdenum hydrogenation refining catalyst. The method involves dissolving cobalt acetate in water and then adding ethylenediamine at a molar ratio of 1:1.5–3 to form a cobalt-ethylenediamine mixed solution. Concentrated ammonia is added to the solution to adjust the pH to 12–14, followed by the addition of ammonium molybdate, which is then fully dissolved to prepare a co-impregnation solution containing cobalt and molybdenum metals. A porous support is then impregnated with this solution to prepare the catalyst. A drawback of this method is that calcination in an oxygen-free or micro-oxygen atmosphere is required to obtain the catalyst product.

[0020] ZL00122922.2 discloses a catalyst for hydrodesulfurization of distillate oil and its preparation method. The catalyst uses alumina or silica-containing alumina as a support, Mo-Ni as the active component, and adds phosphorus additives. The catalyst is prepared by staged co-impregnation of the support with an alkaline Mo-Ni-P co-impregnation solution, followed by stepwise co-impregnation of the support. This patent uses two or more steps to prepare the catalyst.

[0021] US4409131 discloses a method for preparing a CoMo / NiMo catalyst, which is prepared by impregnating a support with a solution containing an active component and ammonia in one step. The method details the preparation process of the impregnation solution for the active component. During the preparation of the impregnation solution, the mixture needs to be heated to promote the dissolution of the active component.

[0022] US6013598 discloses a method for preparing a selective hydrodesulfurization catalyst, which consists of active components cobalt and molybdenum and a support alumina. It is prepared by impregnating the support with an equal volume of an aqueous solution containing the active components and citric acid. The catalyst obtained by this method can only reach a maximum molybdenum oxide content of 10 wt%.

[0023] The literature “Preparation of Co-Mo-Ni-W / γ-Al2O3 diesel hydrorefining catalyst” investigated the effects of pore-expanding agents and calcination temperature on the physicochemical properties of the support and the effects of the impregnation solution preparation method on its stability. There are two main methods for preparing the impregnation solution: (1) Low temperature method: ① Heat deionized water and phosphoric acid, add basic nickel carbonate (or basic cobalt carbonate) and molybdenum trioxide, continue heating and stirring until dissolved, and cool to room temperature for later use; ② Add ammonium metatungstate and cobalt acetate (or nickel nitrate) to slightly heated deionized water, stir to dissolve, and cool to room temperature for later use; ③ Mix the cooled ammonium metatungstate and cobalt acetate (or nickel nitrate) solution with the nickel (cobalt) molybdenum phosphorus solution prepared in ①, stir evenly, and then make up to a final volume for later use. (2) High-temperature preparation: Dissolve molybdenum trioxide, phosphoric acid, and basic nickel carbonate (or basic cobalt carbonate) in deionized water, heat and stir until completely dissolved, then add ammonium metatungstate and cobalt acetate (or nickel nitrate), continue heating and stirring until completely dissolved into a clear solution, and then make up to volume for later use. Heating and the addition of inorganic acid are required in the preparation of the impregnation solution.

[0024] CN94114194.2 discloses a hydrocarbon hydrodesulfurization catalyst and its preparation method. The catalyst uses zinc oxide-modified γ-Al₂O₃ as a support and cobalt and molybdenum as active components, prepared by a single impregnation with a co-impregnation solution of cobalt and molybdenum. The resulting catalyst has the following composition: CoO 1–10 wt%, MoO₃ 5–18 wt%, ZnO 1–15 wt%, with the balance being γ-Al₂O₃. However, the long-term stability of the catalyst requires further investigation. Summary of the Invention

[0025] The purpose of this invention is to provide a method for hydrorefining catalytic cracking gasoline. This method uses a catalyst prepared by a pre-spraying method, in which the active components have a more reasonable gradient distribution, thereby giving the catalyst a better hydrorefining performance. At the same time, due to the reasonable gradient distribution of active components, the catalyst of this invention reduces the amount of sulfurizing agent required for pre-sulfurization treatment, significantly reduces hydrogen sulfide emissions during start-up, reduces environmental pollution, and lowers production costs and operational safety risks.

[0026] To achieve the above objectives, this invention provides a method for hydrorefining catalytic cracking gasoline. A pre-sulfurized hydrorefining catalyst is loaded into a fixed-bed reactor. After sulfiding the hydrorefining catalyst, catalytic cracking gasoline and hydrogen are mixed, preheated, and then introduced into the fixed-bed reactor for reaction. The reaction conditions are: reaction temperature 240–360°C, reaction pressure 1.5–4.0 MPa, and space velocity 0.5–4 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-600:1; the preparation method of the hydrorefining catalyst is as follows: the support is atomized and sprayed with a pre-spraying solution, and then aged after spraying to obtain a pre-treated support. The pre-spraying solution is an aqueous solution of citric acid or a potassium hydroxide solution; the pre-treated support is impregnated with an impregnation solution containing active components, and then aged, dried and calcined to obtain the hydrorefining catalyst.

[0027] The catalytic cracking gasoline hydrorefining method of the present invention wherein the pre-sulfurization method of the hydrorefining catalyst is to mix the pre-sulfurized raw material with the hydrorefining catalyst by spraying.

[0028] The method for hydrorefining catalytic cracking gasoline according to the present invention comprises a pre-sulfurized feedstock being a mixture of a sulfiding agent and a sulfidation aid; the amount of the sulfiding agent is 20-70% of the theoretical sulfur requirement of the hydrorefining catalyst, preferably 25-50%; and the amount of the sulfidation aid is 0.5-40% of the weight of the hydrorefining catalyst, preferably 3-25%.

[0029] The theoretical sulfur requirement for a hydrogenation catalyst refers to the amount of sulfur required for the complete conversion of the active metal components in the oxidized hydrogenation catalyst into sulfides such as Co9S8, MoS2, Ni3S2, and WS2. To ensure uniform mixing of the sulfiding agent and the oxidized hydrogenation catalyst, an appropriate amount of sulfidation aid can be added.

[0030] In this invention, the vulcanizing agent used is a conventional sulfur-containing substance in the art, which can be one or more of elemental sulfur and / or sulfur-containing compounds. It can be a single substance or a mixture. The sulfur-containing compound can be at least one of inorganic sulfur-containing compounds and organic sulfur-containing compounds. The inorganic sulfur-containing compound can be at least one of carbon disulfide and ammonium sulfide. The organic sulfur-containing compound can be at least one of monosulfide and polysulfide compounds, such as one or more of dimethyl disulfide, tert-butyl polysulfide, tert-nonyl polysulfide, thiourea, SZ-54 (commercial), thiols (such as n-butyl mercaptan, ethyl mercaptan), thiophenol, and thioether.

[0031] In this invention, the vulcanizing aid used is a commonly used organic solvent in the art, such as one or more of hydrocarbon oils and organic carboxylic acid esters. The hydrocarbon oil used can be one or more of gasoline, kerosene, diesel, kerosene, white oil, industrial soybean oil, lubricating oil base oil, etc., preferably hydrocarbon oils obtained through secondary processing, such as those obtained through catalytic cracking, thermal cracking, etc. The organic carboxylic acid ester used can be an organic carboxylic acid ester containing 6 to 60 carbon atoms, preferably one or more of fatty acid glycerides, animal oils, rapeseed oil, peanut oil, soybean oil, cottonseed oil, etc.

[0032] The catalytic cracking gasoline hydrorefining method of the present invention includes a sulfidation method for the hydrorefining catalyst in which, under hydrogen circulation conditions, the reactor inlet temperature is increased at a rate of 15-25°C / hour; when the catalyst bed temperature reaches 150-160°C, it is kept at a constant temperature for 3-5 hours; when the catalyst bed temperature reaches 180-220°C, it is kept at a constant temperature for 2-10 hours; and when the catalyst bed temperature reaches 260-320°C, it is kept at a constant temperature for 3-9 hours.

[0033] The catalytic cracking gasoline hydrorefining method of the present invention uses the following reaction conditions for the hydrorefining reaction: reaction temperature 280–340°C, reaction pressure 2–4 MPa, and space velocity 1–3 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200–400:1.

[0034] In the catalytic cracking gasoline hydrorefining method of the present invention, when the carrier is pre-sprayed with citric acid aqueous solution, inorganic acid components are also added to the impregnation solution.

[0035] In the catalytic cracking gasoline hydrorefining method of the present invention, when pre-spraying the carrier with potassium hydroxide solution, ammonia water is also added to the impregnation solution, and potassium hydroxide and / or a polyamine complexing agent may be selectively added. Specifically, for example, ammonia water and potassium hydroxide are added to the impregnation solution; or ammonia water and a polyamine complexing agent are added to the impregnation solution; or ammonia water, a polyamine complexing agent and potassium hydroxide are added to the impregnation solution; or only ammonia water is added. In the present invention, the polyamine complexing agent is a commonly used complexing agent in the art, such as ethylenediamine or ethylenediaminetetraacetic acid.

[0036] The catalytic cracking gasoline hydrorefining method of the present invention comprises molybdenum and nickel as active components, and may optionally contain cobalt.

[0037] In this invention, the active component molybdenum is preferably added in the form of ammonium molybdate / molybdenum oxide; the active components cobalt and nickel can be added in the form of their sulfates, halides, nitrates or acetates. Since the nitrates and acetates of cobalt and nickel have good solubility, which is beneficial to the distribution of the active components on the carrier, the active components cobalt and nickel are preferably added in the form of cobalt nitrate and / or cobalt acetate, nickel nitrate and / or nickel acetate.

[0038] The catalytic cracking gasoline hydrorefining method of the present invention has a spraying treatment time of 1-20 min, preferably 3-10 min; and an aging treatment time of 5-30 min, preferably 10-20 min.

[0039] The catalytic cracking gasoline hydrorefining method of the present invention uses a support with a specific surface area of ​​120-260 m². 2 / g, preferably 150-220m 2 / g; the water absorption rate of the carrier is 70% to 120%, preferably 80% to 100%.

[0040] In this invention, the carrier is directly loaded with the active component for catalyst preparation without drying and calcination after spray aging. The pre-spray solution is prepared by dissolving citric acid or potassium hydroxide in deionized water. The mass content of citric acid or potassium hydroxide in the pre-spray solution is 0.1 wt% to 5 wt%, preferably 0.5 wt% to 1 wt%. The volume percentage of the pre-spray solution added to the catalyst carrier during the atomization spraying process is 1% to 20% of the total impregnation liquid volume (including the volume of the pre-spray solution and the volume of the active component impregnation liquid), preferably 5% to 10%.

[0041] In this invention, the water absorption rate is expressed as X, such as X = 0.9 if the water absorption rate is 90%; the mass of the spray carrier is expressed as T grams. The volume of the active component impregnation solution is 1.05 × (1 - percentage added to the pre-spray solution) × T ~ 1.25 × (1 - percentage added to the pre-spray solution) × T ml, preferably 1.10 × (1 - percentage added to the pre-spray solution) × T ~ 1.20 × (1 - percentage added to the pre-spray solution) × T ml.

[0042] The catalytic cracking gasoline hydrorefining method of the present invention, wherein the hydrorefining catalyst, based on 100% of the total catalyst mass, has a molybdenum oxide content of 11-19 wt%, preferably 13-17 wt%; and a total nickel oxide and cobalt oxide content of 0.5-5 wt%, preferably 1-4.2 wt%. The catalyst may also be free of cobalt oxide depending on the actual situation.

[0043] Beneficial effects of this invention:

[0044] The inventors discovered that in existing technologies, the impregnation step of the active component during the preparation of hydrogenation catalysts involves a concentrated release of adsorption heat, affecting the dispersion state of the active component and the physicochemical properties of the catalyst in the later stages. Based on this, the present invention pre-sprays the catalyst support during the preparation of the hydrogenation refining catalyst, thereby pre-releasing some of the adsorption heat generated during catalyst preparation. Simultaneously, the spray liquid interacts with the support to adjust its properties, resulting in a more rational gradient distribution of the active components in the catalyst. Furthermore, this unexpectedly reduces the amount of sulfiding agent required during the external pre-sulfidation process.

[0045] Sulfidation plays a crucial role in catalyst performance. The pre-sulfided catalyst and corresponding start-up method of this invention facilitate the formation of highly active type II active centers. After sulfidation, the active phase lamellae have a more appropriate number of stacked layers and lamellar length. Furthermore, the active components of the catalyst of this invention form a certain gradient, while simultaneously regulating the interaction between the active metal and the support. The partially sulfided catalyst maintains excellent hydrorefining performance while reducing the amount of sulfiding agent required. During catalyst use, sulfides contained in the oil cause the catalyst's performance to be released slowly. Using the pre-sulfided hydrotreating catalyst and its start-up method of this invention reduces the amount of sulfiding agent used in the pre-sulfidation process, ensuring a safe and stable start-up process and excellent catalyst performance. Detailed Implementation

[0046] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0047] Example 1

[0048] The substrate used in the experiment was a cloverleaf-shaped alumina substrate with a specific surface area of ​​169 m². 2 / g, water absorption rate 74%.

[0049] (1) First, prepare a potassium hydroxide aqueous solution for pretreatment: prepare 329 ml of a potassium hydroxide solution with a content of 0.3 wt%;

[0050] (2) Weigh 10 kg of alumina and add it to a rotary impregnation pot. Use the prepared potassium hydroxide aqueous solution to spray the carrier with atomized water for 1.5 min. The aging time after spraying is 25 min.

[0051] (3) Add ammonium molybdate to a mixed solution of 5040ml ammonia water and 372g ethylenediaminetetraacetic acid, stir to dissolve, then add cobalt nitrate and nickel nitrate in sequence, and add deionized water to adjust the solution volume to 7885ml;

[0052] (4) The active component impregnation solution prepared in step (3) is impregnated on the carrier treated in step (2), aged for 2 hours, dried at 110°C for 3 hours, and calcined at 520°C for 4 hours to obtain catalyst C1.

[0053] Catalyst pre-sulfurization:

[0054] (1) Mix the sulfiding agent (sulfide and SZ-54, with a sulfur mass ratio of 1:2, and the amount used is 30% of the theoretical sulfur required by catalyst C1) and the sulfidation aid (gasoline, with the amount used is 10% of the weight of catalyst C1) evenly to obtain the pre-sulfided raw material.

[0055] (2) Place catalyst C1 into a rotary impregnation pot, and mix the pre-sulfurization raw material with catalyst C1 by spraying to obtain pre-sulfurization catalyst Cs1.

[0056] Start-up methods and evaluation processes for externally pre-sulfurized catalysts:

[0057] (1) The pre-sulfurized catalyst Cs1 from outside the reactor is loaded into the reactor;

[0058] (2) The device underwent nitrogen gas tightness testing, hydrogen replacement, and hydrogen gas tightness testing, and the tests were passed.

[0059] (3) Under hydrogen circulation, the reactor inlet temperature is increased at a rate of 25℃ / hour. When the catalyst bed temperature reaches 150℃, it is kept at a constant temperature for 5 hours; when the catalyst bed temperature reaches 180℃, it is kept at a constant temperature for 8 hours; when the catalyst bed temperature reaches 280℃, it is kept at a constant temperature for 5 hours, and the catalyst sulfidation ends.

[0060] (4) Using catalytically cracked gasoline as feedstock, the reaction was carried out at an inlet temperature of 240℃, a reaction pressure of 1.8MPa, and a liquid hourly space velocity of 1.5h. -1 The product was operated for 300 hours under a hydrogen-to-oil volume ratio of 100:1. The diene value and bromine value in the product were sampled and analyzed every 24 hours. The average values ​​of the analysis results are shown in Table 4.

[0061] Example 2

[0062] The support used in the experiment was a cylindrical alumina-silica support with a specific surface area of ​​211 m². 2 / g, water absorption rate 79%.

[0063] (1) First, prepare a citric acid aqueous solution for pretreatment: prepare 450 ml of an aqueous solution with a citric acid content of 0.1 wt%;

[0064] (2) Weigh 10 kg of alumina and add it to a rotary impregnation pot. Use the prepared citric acid aqueous solution to spray the carrier with atomized water for 10 min and 5 min after spraying.

[0065] (3) Dissolve molybdenum oxide in an aqueous solution of phosphoric acid, add basic nickel carbonate and stir to dissolve, then add deionized water to adjust the solution volume to 8556 ml;

[0066] (4) The active component impregnation solution prepared in step (3) is impregnated on the carrier treated in step (2), aged for 3 hours, dried at 100°C for 4 hours, and calcined at 500°C for 4 hours to obtain catalyst C2.

[0067] Catalyst pre-sulfurization:

[0068] (1) Mix the sulfiding agent (SZ-54, the amount of which is 40% of the theoretical sulfur required by catalyst C2) and the sulfidation aid (white oil, the amount of which is 18% of the weight of catalyst C2) evenly to obtain the pre-sulfided raw material.

[0069] (2) Place catalyst C2 into a rotary impregnation pot, and mix the pre-sulfurization raw material with catalyst C2 by spraying to obtain pre-sulfurization catalyst Cs2.

[0070] Start-up methods and evaluation processes for externally pre-sulfurized catalysts:

[0071] (1) The pre-sulfurized catalyst Cs2 is loaded into the reactor;

[0072] (2) The device underwent nitrogen gas tightness testing, hydrogen replacement, and hydrogen gas tightness testing, and the tests were passed.

[0073] (3) Under hydrogen circulation, the reactor inlet temperature is increased at a rate of 20℃ / hour. When the catalyst bed temperature reaches 150℃, it is kept at a constant temperature for 5 hours; when the catalyst bed temperature reaches 185℃, it is kept at a constant temperature for 7 hours; when the catalyst bed temperature reaches 295℃, it is kept at a constant temperature for 3 hours, and the catalyst sulfidation ends.

[0074] (4) Using catalytically cracked gasoline as feedstock, the reaction was carried out at an inlet temperature of 260℃, a reaction pressure of 2.5MPa, and a liquid hourly space velocity of 2.0h. -1 The product was operated for 300 hours under a hydrogen-to-oil volume ratio of 200:1. The diene value and bromine value in the product were sampled and analyzed every 24 hours. The average values ​​of the analysis results are shown in Table 4.

[0075] Example 3

[0076] The substrate used in the experiment was a cloverleaf-shaped alumina-titanium oxide support with a specific surface area of ​​152 m². 2 / g, water absorption rate 71%.

[0077] (1) First, prepare a citric acid aqueous solution for pretreatment: prepare 542 ml of an aqueous solution with a citric acid content of 0.4 wt%;

[0078] (2) Weigh 10 kg of alumina and add it to a rotary impregnation pot. Use the prepared citric acid solution to spray the carrier with atomized solution for 3 min. The aging time after spraying is 20 min.

[0079] (3) Dissolve molybdenum oxide in an aqueous solution of phosphoric acid, add nickel nitrate and stir to dissolve, then add deionized water to adjust the solution volume to 7197 ml;

[0080] (4) The active component impregnation solution prepared in step (3) is impregnated on the carrier treated in step (2), aged for 3.5 h, dried at 100 °C for 5 h, and calcined at 430 °C for 6 h to obtain catalyst C3.

[0081] Catalyst pre-sulfurization:

[0082] (1) Mix the sulfiding agent (tert-butyl polysulfide and SZ-54, with a sulfur mass ratio of 1:2 and a dosage of 20% of the theoretical sulfur required for catalyst C3) and the sulfidation aid (diesel, with a dosage of 1.5% of the weight of catalyst C3) evenly to obtain the pre-sulfided raw material.

[0083] (2) Place catalyst C3 into a rotary impregnation pot, and mix the pre-sulfurization raw material with catalyst C3 by spraying to obtain pre-sulfurization catalyst Cs3.

[0084] Start-up methods and evaluation processes for externally pre-sulfurized catalysts:

[0085] (1) The pre-sulfurized catalyst Cs3 is loaded into the reactor;

[0086] (2) The device underwent nitrogen gas tightness testing, hydrogen replacement, and hydrogen gas tightness testing, and the tests were passed.

[0087] (3) Under hydrogen circulation, the reactor inlet temperature is increased at a rate of 25℃ / hour. When the catalyst bed temperature reaches 155℃, it is kept at a constant temperature for 4 hours; when the catalyst bed temperature reaches 210℃, it is kept at a constant temperature for 2 hours; when the catalyst bed temperature reaches 300℃, it is kept at a constant temperature for 9 hours, and the catalyst sulfidation ends.

[0088] (4) Using catalytically cracked gasoline as feedstock, the reaction was carried out at an inlet temperature of 270℃, a reaction pressure of 2.8MPa, and a liquid hourly space velocity of 1.0h. -1 The product was operated for 300 hours under a hydrogen-to-oil volume ratio of 300:1. The diene value and bromine value in the product were sampled and analyzed every 24 hours. The average values ​​of the analysis results are shown in Table 4.

[0089] Example 4

[0090] The substrate used in the experiment was a four-leaf clover-shaped alumina-silica substrate with a specific surface area of ​​183 m². 2 / g, water absorption rate 77%.

[0091] (1) First, prepare a potassium hydroxide aqueous solution for pretreatment: prepare 494 ml of a potassium hydroxide solution with a content of 0.5 wt%;

[0092] (2) Weigh 10 kg of alumina and add it to a rotary impregnation pot. Use the prepared potassium hydroxide solution to spray the carrier with atomized solution for 7 min. The aging time after spraying is 18 min.

[0093] (3) Add ammonium molybdate to a mixed solution of 4970ml ammonia, 502g ethylenediamine and 208g potassium hydroxide, stir to dissolve, add cobalt nitrate and nickel nitrate in sequence, and add deionized water to adjust the solution volume to 7745ml.

[0094] (4) The active component impregnation solution prepared in step (3) is impregnated on the carrier treated in step (2), aged for 4 hours, dried at 120°C for 2 hours, and calcined at 480°C for 4 hours to obtain catalyst C4.

[0095] Catalyst pre-sulfurization:

[0096] (1) Mix the sulfiding agent (elemental sulfur, the amount of which is 35% of the theoretical sulfur required for catalyst C4) and the sulfidation aid (kerosene, the amount of which is 3% of the weight of catalyst C4) evenly to obtain the pre-sulfided raw material.

[0097] (2) Place the catalyst C4 into a rotary impregnation pot, and mix the pre-sulfurization raw material with the catalyst C4 by spraying to obtain the pre-sulfurization catalyst Cs4.

[0098] Start-up methods and evaluation processes for externally pre-sulfurized catalysts:

[0099] (1) The pre-sulfurized catalyst Cs4 is loaded into the reactor;

[0100] (2) The device underwent nitrogen gas tightness testing, hydrogen replacement, and hydrogen gas tightness testing, and the tests were passed.

[0101] (3) Under hydrogen circulation, the reactor inlet temperature is increased at a rate of 15℃ / hour. When the catalyst bed temperature reaches 150℃, it is kept at a constant temperature for 4 hours; when the catalyst bed temperature reaches 185℃, it is kept at a constant temperature for 4 hours; when the catalyst bed temperature reaches 285℃, it is kept at a constant temperature for 7 hours, and the catalyst sulfidation ends.

[0102] (4) Using catalytically cracked gasoline as feedstock, the reaction was carried out at an inlet temperature of 320℃, a reaction pressure of 3.0 MPa, and a liquid hourly space velocity of 2.0 h⁻¹. -1 The product was operated for 300 hours under a hydrogen-to-oil volume ratio of 400:1. The diene value and bromine value in the product were sampled and analyzed every 24 hours. The average values ​​of the analysis results are shown in Table 4.

[0103] Example 5

[0104] The substrate used in the experiment was a clover-shaped alumina substrate with a specific surface area of ​​248 m². 2 / g, water absorption rate 92%.

[0105] (1) First, prepare a citric acid aqueous solution for pretreatment: prepare 1225 ml of an aqueous solution with a citric acid content of 2.5 wt%;

[0106] (2) Weigh 10 kg of alumina and add it to a rotary impregnation pot. Use the prepared citric acid aqueous solution to spray the carrier with atomized water for 15 min. The aging time after spraying is 15 min.

[0107] (3) Dissolve ammonium molybdate in an aqueous solution of phosphoric acid, add nickel nitrate and cobalt nitrate, stir to dissolve, and then add deionized water to adjust the solution volume to 9907 ml;

[0108] (4) The active component impregnation solution prepared in step (3) is impregnated on the carrier treated in step (2), aged for 6 hours, dried at 100°C for 4 hours, and calcined at 450°C for 5 hours to obtain catalyst C5.

[0109] Catalyst pre-sulfurization:

[0110] (1) Mix the sulfiding agent (elemental sulfur and ammonium sulfide, with a sulfur mass ratio of 2:1 and an amount of 65% of the theoretical sulfur required for catalyst C5) and the sulfidation aid (white oil, with an amount of 12% of the weight of catalyst C5) evenly to obtain the pre-sulfided raw material.

[0111] (2) Place catalyst C5 into a rotary impregnation pot, and mix the pre-sulfurization raw material with catalyst C5 by spraying to obtain pre-sulfurization catalyst Cs5.

[0112] Start-up methods and evaluation processes for externally pre-sulfurized catalysts:

[0113] (1) The pre-sulfurized catalyst Cs5 is loaded into the reactor;

[0114] (2) The device underwent nitrogen gas tightness testing, hydrogen replacement, and hydrogen gas tightness testing, and the tests were passed.

[0115] (3) Under hydrogen circulation, the reactor inlet temperature is increased at a rate of 15℃ / hour. When the catalyst bed temperature reaches 160℃, it is kept at a constant temperature for 3 hours; when the catalyst bed temperature reaches 220℃, it is kept at a constant temperature for 5 hours; when the catalyst bed temperature reaches 290℃, it is kept at a constant temperature for 6 hours, and the catalyst sulfidation ends.

[0116] (4) Using catalytically cracked gasoline as feedstock, the reaction was carried out at an inlet temperature of 340℃, a reaction pressure of 3.5MPa, and a liquid hourly space velocity of 2.5h.-1 The product was operated for 300 hours under a hydrogen-to-oil volume ratio of 500:1. The diene value and bromine value in the product were sampled and analyzed every 24 hours. The average values ​​of the analysis results are shown in Table 4.

[0117] Example 6

[0118] The substrate used in the experiment was a four-leaf clover-shaped alumina-zirconia support with a specific surface area of ​​237 m². 2 / g, water absorption rate 86%.

[0119] (1) First, prepare a potassium hydroxide aqueous solution for pretreatment: prepare 1015 ml of a potassium hydroxide solution with a content of 1.0 wt%;

[0120] (2) Weigh 10 kg of alumina and add it to a rotary impregnation pot. Use the prepared potassium hydroxide solution to spray the carrier with atomized solution for 4.5 min. The aging time after spraying is 12 min.

[0121] (3) Add ammonium molybdate to 6500ml of ammonia water, stir to dissolve, add nickel nitrate in sequence after stirring to dissolve, and add deionized water to adjust the solution volume to 9133ml;

[0122] (4) The active component impregnation solution prepared in step (3) is impregnated on the carrier treated in step (2), aged for 5 hours, dried at 110°C for 5 hours, and calcined at 470°C for 6 hours to obtain catalyst C6.

[0123] Catalyst pre-sulfurization:

[0124] (1) Mix the sulfiding agent (thiophenol and elemental sulfur in a sulfur mass ratio of 1:2, with an amount of 60% of the theoretical sulfur required for catalyst C6) and the sulfidation aid (white oil, with an amount of 25% of the weight of catalyst C6) evenly to obtain the pre-sulfided raw material.

[0125] (2) Place the catalyst C6 into a rotary impregnation pot, and mix the pre-sulfurization raw material with the catalyst C6 by spraying to obtain the pre-sulfurization catalyst Cs6.

[0126] Start-up methods and evaluation processes for externally pre-sulfurized catalysts:

[0127] (1) The pre-sulfurized catalyst Cs6 is loaded into the reactor;

[0128] (2) The device underwent nitrogen gas tightness testing, hydrogen replacement, and hydrogen gas tightness testing, and the tests were passed.

[0129] (3) Under hydrogen circulation, the reactor inlet temperature is increased at a rate of 20℃ / hour. When the catalyst bed temperature reaches 160℃, it is kept at a constant temperature for 3 hours; when the catalyst bed temperature reaches 200℃, it is kept at a constant temperature for 6 hours; when the catalyst bed temperature reaches 270℃, it is kept at a constant temperature for 8 hours, and the catalyst sulfidation ends.

[0130] (4) Using catalytically cracked gasoline as feedstock, the reaction was carried out at an inlet temperature of 300℃, a reaction pressure of 4.0 MPa, and a liquid hourly space velocity of 3.0 h⁻¹. -1 The product was operated for 300 hours under a hydrogen-to-oil volume ratio of 600:1. The diene value and bromine value in the product were sampled and analyzed every 24 hours. The average values ​​of the analysis results are shown in Table 4.

[0131] Example 7

[0132] The substrate used in the experiment was a cloverleaf-shaped alumina substrate with a specific surface area of ​​225 m². 2 / g, water absorption rate 83%.

[0133] (1) First, prepare a potassium hydroxide aqueous solution for pretreatment: prepare 770 ml of a potassium hydroxide solution with a content of 0.8 wt%;

[0134] (2) Weigh 10 kg of alumina and add it to a rotary impregnation pot. Use the prepared potassium hydroxide solution to spray the carrier with atomized solution for 4 min. The aging time after spraying is 5 min.

[0135] (3) Add ammonium molybdate to a mixed solution of 4350ml ammonia and 425ml ethylenediamine, stir to dissolve, add nickel nitrate in sequence after stirring and dissolving, and add deionized water to adjust the solution volume to 8858ml.

[0136] (4) The active component impregnation solution prepared in step (3) is impregnated on the carrier treated in step (2), aged for 4.5 h, dried at 120 °C for 3 h, and calcined at 480 °C for 5 h to obtain catalyst C7.

[0137] Catalyst pre-sulfurization:

[0138] (1) Mix the sulfiding agent (SZ-54, the amount of which is 45% of the theoretical sulfur required by catalyst C7) and the sulfidation aid (lubricating oil base oil, the amount of which is 8% of the weight of catalyst C7) evenly to obtain the pre-sulfided raw material.

[0139] (2) Place the catalyst C7 into a rotary impregnation pot, and mix the pre-sulfurization raw material with the catalyst C7 by spraying to obtain the pre-sulfurization catalyst Cs7.

[0140] Start-up methods and evaluation processes for externally pre-sulfurized catalysts:

[0141] (1) The pre-sulfurized catalyst Cs7 is loaded into the reactor;

[0142] (2) The device underwent nitrogen gas tightness testing, hydrogen replacement, and hydrogen gas tightness testing, and the tests were passed.

[0143] (3) Under hydrogen circulation, the reactor inlet temperature is increased at a rate of 15℃ / hour. When the catalyst bed temperature reaches 155℃, it is kept at a constant temperature for 4 hours; when the catalyst bed temperature reaches 190℃, it is kept at a constant temperature for 10 hours; when the catalyst bed temperature reaches 260℃, it is kept at a constant temperature for 4 hours, and the catalyst sulfidation ends.

[0144] (4) Using catalytically cracked gasoline as feedstock, the reaction was carried out at an inlet temperature of 280℃, a reaction pressure of 3.2MPa, and a liquid hourly space velocity of 3.5h. -1 The product was operated for 300 hours under a hydrogen-to-oil volume ratio of 350:1. The diene value and bromine value in the product were sampled and analyzed every 24 hours. The average values ​​of the analysis results are shown in Table 4.

[0145] Comparative Example 1

[0146] The substrate used in the experiment was a cloverleaf-shaped alumina substrate with a specific surface area of ​​169 m². 2 / g, water absorption rate 74%.

[0147] Ammonium molybdate was added to a mixed solution of 5040 ml ammonia and 372 g ethylenediaminetetraacetic acid. After stirring and dissolving, cobalt nitrate and nickel nitrate were added sequentially, and deionized water was added to adjust the solution volume to 8214 ml to obtain the active component solution. The prepared active component impregnation solution was impregnated onto a 10 kg carrier, aged for 2 h, dried at 110 °C for 3 h, and calcined at 520 °C for 4 h to obtain catalyst D1.

[0148] Catalyst pre-sulfurization:

[0149] (1) Mix the sulfiding agent (sulfide and SZ-54, with a sulfur mass ratio of 1:2, and the amount is 30% of the theoretical sulfur required by catalyst D1) and the sulfidation aid (gasoline, with the amount being 10% of the weight of catalyst D1) evenly to obtain the pre-sulfided raw material.

[0150] (2) Place catalyst D1 into a rotary impregnation pot, and mix the pre-sulfurization raw material with catalyst D1 by spraying to obtain pre-sulfurization catalyst Ds1.

[0151] The start-up method and evaluation process for the pre-sulfurized catalyst outside the reactor are the same as in Example 1.

[0152] Comparative Example 2

[0153] The substrate used in the experiment was a cloverleaf-shaped alumina-titanium oxide support with a specific surface area of ​​152 m². 2 / g, water absorption rate 71%.

[0154] Molybdenum oxide was dissolved in an aqueous phosphoric acid solution, and nickel nitrate was added and stirred until dissolved. Deionized water was then added to adjust the solution volume to 7739 ml to obtain the active component solution. The prepared active component impregnation solution was impregnated onto a 10 kg support, aged for 3.5 h, dried at 100 °C for 5 h, and calcined at 430 °C for 6 h to obtain catalyst D2.

[0155] Catalyst pre-sulfurization:

[0156] (1) Mix the sulfiding agent (tert-butyl polysulfide and SZ-54, with a sulfur mass ratio of 1:2 and a dosage of 20% of the theoretical sulfur required by catalyst D2) and the sulfidation aid (diesel, with a dosage of 1.5% of the weight of catalyst D2) evenly to obtain the pre-sulfided raw material.

[0157] (2) Place catalyst D2 into a rotary impregnation pot, and mix the pre-sulfurization raw material with catalyst D2 by spraying to obtain pre-sulfurization catalyst Ds2.

[0158] The start-up method and evaluation process for the pre-sulfurized catalyst outside the reactor are the same as in Example 3.

[0159] Comparative Example 3

[0160] The substrate used in the experiment was a clover-shaped alumina substrate with a specific surface area of ​​248 m². 2 / g, water absorption rate 92%.

[0161] Molybdenum oxide was dissolved in an aqueous phosphoric acid solution. Nickel nitrate and cobalt nitrate were added and stirred until dissolved. Deionized water was then added to adjust the solution volume to 11132 ml to obtain the active component solution. The prepared active component impregnation solution was impregnated onto a 10 kg support, aged for 6 h, dried at 100 °C for 4 h, and calcined at 450 °C for 5 h to obtain catalyst D3.

[0162] Catalyst pre-sulfurization:

[0163] (1) Mix the sulfiding agent (elemental sulfur and ammonium sulfide, with a sulfur mass ratio of 2:1 and an amount of 65% of the theoretical sulfur required by catalyst D3) and the sulfidation aid (white oil, with an amount of 12% of the weight of catalyst D3) evenly to obtain the pre-sulfided raw material.

[0164] (2) Place catalyst D3 into a rotary impregnation pot, and mix the pre-sulfurization raw material with catalyst D3 by spraying to obtain pre-sulfurization catalyst Ds3.

[0165] The start-up method and evaluation process for the pre-sulfurized catalyst outside the reactor are the same as in Example 5.

[0166] Comparative Example 4

[0167] The substrate used in the experiment was a cloverleaf-shaped alumina substrate with a specific surface area of ​​225 m².2 / g, water absorption rate 83%.

[0168] Ammonium molybdate was added to a mixed solution of 4350 ml ammonia and 425 ml ethylenediamine and stirred until dissolved. Nickel nitrate was then added sequentially, followed by deionized water to adjust the solution volume to 9628 ml, yielding the active component solution. The prepared active component impregnation solution was then impregnated onto a 10 kg carrier, aged for 4.5 h, dried at 120 °C for 3 h, and calcined at 480 °C for 5 h to obtain catalyst D4.

[0169] Catalyst pre-sulfurization:

[0170] (1) Mix the sulfiding agent (SZ-54, the amount of which is 45% of the theoretical sulfur required by catalyst D4) and the sulfidation aid (lubricating oil base oil, the amount of which is 8% of the weight of catalyst D4) evenly to obtain the pre-sulfided raw material.

[0171] (2) Place catalyst D4 into a rotary impregnation pot, and mix the pre-sulfurization raw material with catalyst D4 by spraying to obtain pre-sulfurization catalyst Ds4.

[0172] The start-up method and evaluation process for the pre-sulfurized catalyst outside the reactor are the same as in Example 7.

[0173] Table 1. Mass content of each component in the catalyst

[0174] Example molybdenum oxide wt% Nickel oxide wt% Cobalt oxide wt% Example 1 16.5 2.1 1.4 Example 2 12.4 1.9 0 Example 3 17.5 1.7 0 Example 4 13.9 0.8 2.1 Example 5 16.8 1.3 2.8 Example 6 16.2 2.8 0 Example 7 17.8 1.1 0 Comparative Example 1 16.5 2.1 1.4 Comparative Example 2 17.5 1.7 0 Comparative Example 3 16.8 1.3 2.8 Comparative Example 4 17.8 1.1 0

[0175] The elemental distribution of the presulfurized catalysts prepared in Examples 1-7 and Comparative Examples 1-4 was characterized by SEM-EDS, which revealed the distribution of active components on the catalysts. The content of active components at different positions of the presulfurized catalysts prepared in Examples 1-7 and Comparative Examples 1-4 is shown in Table 2.

[0176] Table 2. Percentage (%) of metal content of active components at different locations in the catalyst to the total content of active components.

[0177] Example From center to 1 / 4 radius 1 / 4 to 1 / 2 radius 1 / 2 to 3 / 4 radius 3 / 4 radius to surface Example 1 3.1 5.7 11.5 79.7 Example 2 2.9 8.9 8.4 79.8 Example 3 2.5 9.2 9.7 78.6 Example 4 1.8 7.8 13.2 77.2 Example 5 2.3 6.5 10.8 80.4 Example 6 3.4 8.1 12.4 76.1 Example 7 2.6 7.4 10.1 79.9 Comparative Example 1 8.7 16.2 26.4 48.7 Comparative Example 2 7.5 17.7 22.7 52.1 Comparative Example 3 8.4 16.6 23.5 51.5 Comparative Example 4 7.8 15.3 27.9 49

[0178] The product of the first stage hydrogenation of catalytic cracked gasoline was used as feedstock, and the properties of the feedstock are shown in Table 3.

[0179] Table 3 Hydrogenation Feedstock Indicators

[0180]

[0181] The catalyst was evaluated in a single-stage adiabatic fixed-bed reactor with a catalyst loading of 100 mL. The catalyst evaluation results are shown in Table 4.

[0182] Table 4. Hydrogenation results of Examples 1-7 and Comparative Examples 1-4

[0183]

[0184] Data analysis from the examples and comparative examples shows that the concentration distribution of active components in the catalyst prepared by the hydrogenation method of the present invention, along with the preparation method of the hydrogenation catalyst and the external pre-sulfurization method of the present invention, is more reasonable. The evaluation results in Table 4 show that, under the same evaluation process conditions, the catalyst performance of the examples is better than that of the comparative examples, indicating that the catalyst prepared by the preparation method of the hydrogenation catalyst and the external pre-sulfurization method of the present invention has superior hydrogenation refining performance.

[0185] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for hydrorefining catalytic cracked gasoline, characterized in that, The pre-sulfurized hydrorefining catalyst was loaded into a fixed-bed reactor. After sulfidation of the hydrorefining catalyst, catalytic cracking gasoline and hydrogen were mixed, preheated, and then introduced into the fixed-bed reactor for reaction. The reaction conditions were: reaction temperature 240~360℃, reaction pressure 1.5~4.0MPa, and space velocity 0.5~4h. -1 The hydrogen-to-oil volume ratio is 100-600:1; the preparation method of the hydrorefining catalyst is as follows: the support is atomized and sprayed with a pre-spraying solution, and then aged after spraying to obtain a pre-treated support. The pre-spraying solution is an aqueous solution of citric acid or a potassium hydroxide solution; the pre-treated support is impregnated with an impregnation solution containing active components, and then aged, dried, and calcined to obtain the hydrorefining catalyst; The volume percentage of the pre-spray solution is 1% to 20% of the total volume of the pre-spray solution and the active component impregnation solution.

2. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, The pre-sulfurization method of the hydrorefining catalyst is to mix the pre-sulfurization raw material with the hydrorefining catalyst by spraying.

3. The method for hydrorefining catalytic cracking gasoline according to claim 2, characterized in that, The pre-sulfurized raw material is a mixture of a sulfiding agent and a sulfidation aid; the amount of the sulfiding agent is 20-70% of the theoretical sulfur requirement of the hydrorefining catalyst; the amount of the sulfidation aid is 0.5-40% of the weight of the hydrorefining catalyst.

4. The method for hydrorefining catalytic cracking gasoline according to claim 3, characterized in that, The amount of the sulfiding agent is 25-50% of the theoretical sulfur requirement of the hydrorefining catalyst; the amount of the sulfidation aid is 3-25% of the weight of the hydrorefining catalyst.

5. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, The sulfidation method of the hydrogen refining catalyst is as follows: under hydrogen circulation conditions, the reactor inlet temperature is increased at a rate of 15~25℃ / hour; when the catalyst bed temperature reaches 150~160℃, it is kept at a constant temperature for 3~5 hours; when the catalyst bed temperature reaches 180~220℃, it is kept at a constant temperature for 2~10 hours; when the catalyst bed temperature reaches 260~320℃, it is kept at a constant temperature for 3~9 hours.

6. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, The reaction conditions for the hydrorefining reaction are: reaction temperature 280-340℃, reaction pressure 2-4 MPa, and space velocity 1-3 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200-400:

1.

7. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, The mass concentration of the pre-spraying solution is 0.1% to 5 wt%, and the volume percentage of the pre-spraying solution is 5% to 10% of the total volume of the pre-spraying solution and the active component impregnation solution.

8. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, The mass concentration of the pre-spraying solution is 0.5%~1wt%.

9. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, When pre-spraying the carrier with a citric acid aqueous solution, inorganic acid components are also added to the impregnation solution.

10. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, When pre-spraying the carrier with potassium hydroxide solution, ammonia water is also added to the impregnation solution, and potassium hydroxide and / or polyamine complexing agents may be selectively added.

11. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, The active components are molybdenum and nickel, and may optionally contain cobalt.

12. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, The spraying treatment time is 1-20 minutes; the aging treatment time is 5-30 minutes.

13. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, The spraying treatment time is 3-10 minutes; the aging treatment time is 10-20 minutes.

14. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, The specific surface area of ​​the carrier is 120~260m². 2 / g; the water absorption rate of the carrier is 70%~120%.

15. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, The specific surface area of ​​the carrier is 150~220m². 2 / g; the water absorption rate of the carrier is 80%~100%.

16. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, In the hydrorefining catalyst, based on the total mass of the catalyst (100%), the molybdenum oxide content is 11-19 wt%; and the total amount of nickel oxide and cobalt oxide is 0.5-5 wt%.

17. The method for hydrorefining catalytic cracking gasoline according to claim 1, characterized in that, In the hydrorefining catalyst, based on the total mass of the catalyst (100%), the molybdenum oxide content is 13-17 wt%; and the total amount of nickel oxide and cobalt oxide is 1-4.2 wt%.

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