Catalytic slurry hydrocracking catalyst and method for preparing the same

Abstract

The application discloses a kind of catalytic oil slurry hydrogenation catalyst and its preparation method.The catalyst includes auxiliary-containing alumina carrier and MoO3,CoO,The carrier has bimodal pore size distribution,smaller aperture is concentrated distribution in 10-40nm,aperture is 10-40nm The pore volume accounted for 20%-40% of total pore volume,relatively large aperture is concentrated distribution in 150-400nm,aperture is 150-400nm The pore volume accounted for 30%-50% of total pore volume.The catalyst of the application is loaded in catalytic cracking oil slurry hydrogenation reactor between hydrogenation guard and hydrogenation desulfurization agent,play the role of upper and lower,so as to realize the preliminary removal of sulfur impurities in catalytic cracking oil slurry,can also accommodate more carbon deposition and other deposits,prolong the operation cycle of device.

Description

Technical Field

[0001] This invention belongs to the field of hydrogenation technology, and specifically relates to a catalyst for catalytic oil slurry hydrogenation and its preparation method. Background Technology

[0002] With the continuous deterioration and increasing heaviness of petroleum resources, the market demand for diversified and lightweight petrochemical products is growing. Processing low-quality, heavy crude oil has become a significant challenge for refineries worldwide. Catalytic cracking technology is one of the three main processes for deep processing of heavy oil and a key technology for lightweighting feedstocks, exhibiting strong adaptability to various feedstocks. Currently, some catalytic cracking units can directly process atmospheric residue or blend with some vacuum residue, leading to problems such as a deterioration in the distribution of catalytic cracking products. To increase unit throughput, reduce energy consumption, and increase lightweight products, external slurry loading is a good solution, but this generates a large amount of catalytic cracking slurry as a byproduct. As a low-value-added product of the catalytic cracking process, catalytic cracking slurry is characterized by high density, high carbon residue, high viscosity, and high aromatic content, and contains residual catalyst particles and coke, making its processing and utilization difficult. Therefore, how to process and utilize catalytic cracking slurry has become a critical issue that refineries urgently need to address.

[0003] Catalytic cracking slurry oil, rich in aromatics, is an ideal raw material for the preparation of high-end carbon-based materials such as needle coke. Needle coke is characterized by high crystallinity, high strength, high graphitization, low thermal expansion, and low ablation, and is mainly used in ultra-high power graphite electrodes and lithium-ion battery anode materials. As a raw material for needle coke production, catalytic cracking slurry oil typically requires low sulfur, low nitrogen, low ash content, and high aromatic content, especially high levels of tricyclic and tetracyclic aromatics.

[0004] Catalytic cracking slurry oil has high density, high carbon residue, high viscosity, high aromatic content, and contains residual catalyst particles and coke, making it difficult to utilize. Currently, high-quality, low-sulfur slurry oil resources are extremely scarce, while inferior slurry oil has a high sulfur content (1.0 wt%–2.0 wt%). Needle coke products have strict requirements for sulfur content (≤0.5 wt%), and using conventional residue hydrotreating catalysts results in excessive aromatic hydrocarbon loss. Currently, research on hydrotreating catalysts specifically for catalytic cracking slurry oil is limited; therefore, developing catalysts suitable for hydrotreating catalytic cracking slurry oil is of great significance.

[0005] CN103013567A discloses a method for producing needle coke feedstock from catalytic cracking slurry. The method includes a protected zone and a hydrotreating reaction zone. The protected zone is filled with an adsorbent capable of adsorbing catalytic cracking catalyst powder. The hydrotreating reaction zone is filled sequentially with a hydrotreating protective agent, a hydrodemetallizing agent, and a hydrodesulfurizing agent according to the flow direction of the reaction stream. The catalytic cracking slurry first enters the protected zone, adsorbing most of the catalytic cracking catalyst powder, and then mixes with hydrogen into a heating furnace. After heating, it enters the hydrotreating reaction zone for hydrotreating. The hydrodemetallizing agent comprises an alumina support and molybdenum and / or tungsten supported on the support, as well as nickel and / or cobalt, wherein the pore distribution of the support is such that the pore volume with a diameter of 100-200 angstroms (10-20 nm) accounts for 70%-98% of the total pore volume; the hydrodesulfurizing agent comprises a support and molybdenum and / or tungsten supported on the support, as well as nickel and / or cobalt, wherein the support is alumina and optionally silicon oxide; wherein the pore distribution of the support is such that the pore volume with a diameter of 60-100 angstroms (6-10 nm) accounts for 75%-98% of the total pore volume. The aforementioned hydrodemetallizing and hydrodesulfurizing agents are all conventional residue hydrotreating catalysts. Although they can be used for hydrotreating catalytic cracking slurry, catalytic cracking slurry has a low metal content, low metal deposits, small pore size of the support, and low macropore volume. During the hydrotreating reaction, the adsorption and reaction of macromolecules such as colloids and asphaltenes in the catalytic cracking slurry will be affected by diffusion resistance. At the same time, the continuous deposition of carbon during the hydrotreating process can easily cause pore blockage, and the carbon deposits will be deposited on the downstream desulfurization catalyst, ultimately leading to unit shutdown.

[0006] Because catalytic cracking slurry feedstock differs from conventional residue feedstock, existing conventional residue hydrotreating catalysts still present the aforementioned problems for catalytic cracking slurry feedstock. Therefore, there is an urgent need to develop catalysts suitable for catalytic cracking slurry hydrotreating. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a catalytic cracking slurry hydrotreating catalyst and its preparation method. This hydrotreating catalyst is installed between the hydrotreating protectant and the hydrodesulfurizing agent in the catalytic cracking slurry hydrotreating reactor, acting as a bridge between them. This achieves the initial removal of sulfur impurities from the catalytic cracking slurry while also accommodating more deposits such as carbon buildup, thus extending the operating cycle of the unit.

[0008] Typically, a residue hydrodemetallization catalyst is placed between the hydroprotectant and the hydrodesulfurization catalyst in a catalytic cracking slurry hydrotreating reactor. Catalytic cracking slurry contains relatively few metal impurities but has a high content of gums and asphaltenes (4.0%–15.0%). Asphaltenes molecules are mainly composed of 5 to 7 plate-like fused aromatic rings with a size of 12–16 angstroms (1.2–1.6 nm), and these molecules are prone to aggregation. Therefore, conventional hydrodemetallization catalysts are not very suitable for catalytic cracking slurry hydrotreating. Through research, the inventors discovered that developing a hydrogenation transition agent with a suitable bimodal pore size distribution can effectively eliminate the diffusion resistance of macromolecules adsorbing and reacting on the catalyst surface during the hydrogenation of catalytic cracking slurry. At the same time, it can accommodate the carbon deposits generated during the reaction, reducing the active sites that are deactivated by carbon deposits. The smaller pore size is conducive to the hydrogenation reaction of small molecules of sulfur-containing compounds such as thiols and thioethers, thereby achieving the initial removal of sulfur impurities in catalytic cracking slurry and accommodating more carbon deposits and other sediments, thus extending the operating cycle of the unit.

[0009] The first aspect of the present invention provides a catalytic cracking slurry hydrogenation catalyst, wherein the catalyst comprises an alumina support containing promoters and MoO3 and CoO, the support having a bimodal pore size distribution, with the smaller pore size concentrated in the range of 10 to 40 nm, the pores with a pore size of 10 to 40 nm accounting for 20% to 40% of the total pore volume, and the larger pore size concentrated in the range of 150 to 400 nm, the pores with a pore size of 150 to 400 nm accounting for 30% to 50% of the total pore volume.

[0010] In this invention, the pore volume of the carrier is 0.95–1.35 cm³. 3 / g, preferably 1.00~1.25cm 3 / g.

[0011] In this invention, the specific surface area of ​​the carrier is 110–175 m². 2 / g, preferably 130-170m 2 / g.

[0012] In this invention, based on the mass of the hydrogenation catalyst, the content of MoO3 is 4.0% to 10.0%, and the content of CoO is 0.8% to 2.5%.

[0013] In this invention, the alumina carrier containing additives preferably contains one or more of fluorine, phosphorus, silicon or boron, and more preferably silicon; the content of the additives, calculated as oxides, accounts for 0.2% to 10% of the total mass of alumina in the carrier, preferably 1% to 6%.

[0014] In this invention, the catalyst is preferably clover-shaped.

[0015] A second aspect of the present invention provides a method for preparing the above-mentioned catalyst, comprising the following steps:

[0016] a) Mix the first aluminum source, the second aluminum source and the third aluminum source with water to obtain a slurry, and then grind the slurry;

[0017] b) Add purified water to the slurry obtained in step a) and stir;

[0018] c) Add pH adjuster, modifier, auxiliary agent precursor and optional dispersant to the material obtained in step b) to obtain a mixed slurry, and then perform hydrothermal treatment on the mixed slurry;

[0019] d) The material obtained in step c) is dried to obtain alumina dry adhesive;

[0020] e) Mix the alumina dry adhesive obtained in step d) with the binder, shape, dry, and calcine to obtain the carrier;

[0021] f) Impregnate the support obtained in step e) with an impregnation solution containing molybdenum and cobalt, and then dry and calcine to obtain the hydrogenation catalyst.

[0022] In the method of the present invention, in step a), the first aluminum source is aluminum oxide trihydrate.

[0023] In the method of this invention, in step a), the second aluminum source is alumina dry adhesive with a water content of less than 35% by mass fraction. The alumina dry adhesive can be a product of dehydration of alumina hydrate; it can be completely dehydrated alumina or partially dehydrated alumina, such as monohydrated alumina.

[0024] In the method of this invention, in step a), the third aluminum source is an aluminum-containing salt compound, which can be an acidic aluminum salt, a basic aluminate, and / or aluminate. The third aluminum source can be selected from at least one of aluminum nitrate, aluminum chloride, aluminum sulfate, sodium aluminate, etc.

[0025] In the method of the present invention, in step a), the mass ratio of the first aluminum source, the second aluminum source and the third aluminum source is 30-66:33-60:1-10.

[0026] In the method of the present invention, in step a), the amount of water added is 100% to 150% of the total mass of the first aluminum source, the second aluminum source and the third aluminum source.

[0027] In the method of the present invention, in step a), the slurry is ground until the particle size in the slurry is 4 to 20 μm, calculated as the median particle size D50.

[0028] In the method of the present invention, in step b), the slurry obtained in step a) is mixed with purified water (preferably deionized water) so that the total mass of the first aluminum source, the second aluminum source and the third aluminum source in the slurry is 10% to 20%.

[0029] In the method of the present invention, in step c), the pH adjuster can be an alkaline substance (such as at least one of sodium hydroxide, ammonia, sodium bicarbonate, ammonium carbonate, etc.) or an acidic substance (such as at least one of acetic acid, citric acid, nitric acid, etc.). The added pH adjuster is adjusted according to the properties of the slurry to control the pH range of the mixed slurry in step c) to be 9.0 to 12.5.

[0030] In the method of this invention, in step c), the dispersant is selected from at least one of hydrophilic dispersants. The dispersant can be a nonionic surfactant with an HLB value (Hydrophile-Lipophile Balance Number) of 10 to 20. The amount of dispersant added is less than 10% of the mass of the material obtained in step b), preferably 0.01% to 10%. The nonionic surfactant dispersant is preferably at least one of Tween-80, lauryl alcohol polyoxyethylene ether, and methyl glucose polyoxyethylene ether. The modifier is preferably at least one of sodium hexametaphosphate, sodium tripolyphosphate, disodium ethylenediaminetetraacetate, sodium gluconate, and sodium tartrate. The amount of the modifier added is 0.01% to 10% of the mass of the material obtained in step b), preferably 0.01% to 6%, and examples, but not limited to: 0.1%, 0.2%, 0.5%, 0.6%, 0.8%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, etc.

[0031] In the method of this invention, in step c), the additive is preferably one or more of fluorine, phosphorus, silicon, or boron, more preferably silicon. Based on the total mass of the first aluminum source, the second aluminum source, and the third aluminum source, the amount of additive (calculated as oxide) added accounts for 0.2% to 10% of the total mass of alumina, preferably 1% to 6%. The fluorine precursor can be at least one of hydrofluoric acid, ammonium fluoride, boron trifluoride, and sodium fluorosilicate; the phosphorus precursor can be at least one of phosphoric acid, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate; the silicon precursor can be at least one of silica sol, water glass, and fluorosilicic acid; and the boron precursor can be at least one of boric acid, sodium borate, ammonium borate, and ammonium metaborate.

[0032] In the method of the present invention, in step c), the conditions for hydrothermal treatment are as follows: temperature is 200-260℃, and hydrothermal time is 4-10 hours.

[0033] In the method of this invention, before drying in step d), the material obtained in step c) can be subjected to filtration and washing. Conventional filtration and washing methods can be used.

[0034] In the method of the present invention, in step d), the drying conditions are: drying temperature is 100-180℃, and drying time is 4-12 hours.

[0035] In the method of this invention, in step e), the binder is selected from at least one of inorganic acid, organic acid, cellulose, and resin, wherein the inorganic acid can be nitric acid, and the organic acid is selected from at least one of acetic acid, citric acid, and tartaric acid. The cellulose is at least one of hydroxypropyl cellulose or methylcellulose, and the resin is at least one of phenolic resin or ethylene-vinyl acetate resin. The amount of binder added is 0.1% to 10% of the mass of the alumina dry adhesive.

[0036] In the method of this invention, in step e), a molding aid, such as an extrusion aid, may be added depending on the molding process. The extrusion aid is selected from guar gum powder; the amount of extrusion aid added is 0.5% to 6.0% of the mass of the alumina dry adhesive obtained in step d).

[0037] In the method of this invention, step e) does not require the addition of pore-forming materials, such as pore expanders. The pore-forming material refers to the material added during the carrier preparation process. During the molding process, the pore expander molecules are encapsulated by alumina powder particles. After high-temperature calcination, the pore expander molecules are oxidized or undergo other chemical reactions to generate gas and escape, leaving behind the previously occupied space, thus forming large pores. Examples of such materials include carbon black and starch.

[0038] In the method of the present invention, in step e), the shaped part can be a four-leaf clover.

[0039] In the method of the present invention, in step e), the drying temperature after molding is 100-180℃, and the drying time is 4-12 hours; the calcination temperature after molding is 500-800℃, and the calcination time is 3-12 hours.

[0040] In the method of this invention, in step f), the impregnation solution containing molybdenum and cobalt contains cobalt at a concentration of 0.7–2.4 g / 100 mL (calculated as cobalt oxide) and molybdenum at a concentration of 3.8–9.6 g / 100 mL (calculated as molybdenum oxide). The molybdenum source can be at least one of ammonium molybdate and molybdenum trioxide. The cobalt source can be at least one of cobalt nitrate and basic cobalt carbonate.

[0041] In the method of the present invention, in step f), the impregnation can be saturated impregnation or supersaturated impregnation, and saturated impregnation is preferred.

[0042] In the method of this invention, in step f), the drying conditions after impregnation are as follows: drying temperature is 100–180°C, and drying time is 4–12 hours; the calcination conditions are as follows: calcination temperature is 450–600°C, and calcination time is 3–6 hours. The calcination atmosphere is an oxygen-containing atmosphere, such as air.

[0043] In this invention, the catalyst is particularly suitable for loading between the hydroprotectant and the highly selective hydrodesulfurization catalyst in a catalytic cracking slurry hydrotreating unit, mainly playing a transitional role, accommodating more carbon deposits and carrying out a simple desulfurization reaction.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1. This invention provides a catalytic cracking slurry hydrogenation catalyst, wherein the support used, as determined by mercury porosimetry, exhibits a bimodal pore size distribution. The smaller pore size is concentrated in the range of 10–40 nm, accounting for 20%–40% of the total pore volume, while the larger pore size is concentrated in the range of 150–400 nm, accounting for 30%–50% of the total pore volume. Catalytic cracking slurry contains relatively low metal content and metal deposits; therefore, larger pores are needed to accommodate the coke deposits generated during the reaction. The support used in this invention, due to its larger pore size, effectively eliminates the diffusion resistance during the adsorption and reaction of large molecules on the catalyst surface during catalytic cracking slurry hydrogenation, accommodates more coke deposits, slows down the pore blockage process, reduces the coverage of active sites by coke deposits, and decreases the catalyst deactivation rate. Furthermore, the smaller pore size facilitates the hydrogenation reaction of small sulfur-containing compounds such as thiols and thioethers. The catalyst of this invention plays a transitional role in the catalytic cracking slurry hydrotreating reactor, serving as a conduit between the upper layer of macroporous hydrotreating protective agent and the lower layer of smaller-pore, highly selective hydrodesulfurization catalyst.

[0046] 2. The catalyst of this invention uses alumina support with a bimodal pore size distribution, with Mo as the main active component and Co as an auxiliary agent. This catalyst exhibits high desulfurization activity and selectivity. Small molecules that readily react, such as thiols and thioethers, preferentially enter the pores for reaction, resulting in a greater retention of tricyclic and tetracyclic aromatic hydrocarbons in the catalytic cracking slurry. The product after hydrogenation of the catalytic cracking slurry is an ideal raw material for preparing high-end carbon-based materials such as needle coke. Detailed Implementation

[0047] The technical solution and effects of the present invention will be further illustrated below through embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0048] Unless otherwise specified, the experimental methods used in the following examples are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following examples were purchased from conventional biochemical reagent stores.

[0049] The pore volume and pore size of the alumina support components, alumina support and catalyst prepared in this invention (including the embodiments), as well as the alumina support components, alumina support and catalyst prepared in Comparative Examples 1, 2 and 4, and the conventional residue hydrodemetallization catalyst support and catalyst, were all measured by mercury porosimetry using a MicroActive AutoPore V 9600 instrument.

[0050] In this invention, the pore volume and pore size of the alumina support components, alumina support and catalyst involved in Comparative Examples 3 and 5 were tested using a low-temperature liquid nitrogen adsorption method with an ASAP2420 pore structure analyzer from Micron Technology, USA.

[0051] The specific surface area of ​​the alumina support components, alumina support and catalyst prepared in this invention (including the examples) and the alumina support components, alumina support and catalyst prepared in the comparative examples was tested using a low-temperature liquid nitrogen adsorption method on an ASAP2420 pore structure analyzer from Micron Technology, USA.

[0052] Example 1

[0053] Take 100g of alumina trihydrate, 100g of boehmite, and 5g of aluminum sulfate, add 250g of purified water, and grind using a ball mill at 450rpm for 1 hour. The particle size (D50) of the slurry is 6.53μm. Add 1100g of purified water to the ground slurry and stir. Then add 5.5g of sodium hydroxide, 3g of sodium hexametaphosphate, and 12g of water glass, bringing the slurry pH to 9.84. Transfer the stirred slurry to an autoclave for hydrothermal treatment at 230℃ for 6 hours. Filter, wash, and dry at 120℃ for 5 hours to obtain alumina dry adhesive GA.

[0054] Take 100g of the prepared alumina dry adhesive, add 2g of guar gum powder, 1g of methylcellulose, 0.5g of acetic acid and 125g of purified water, mix and knead to form a four-leaf clover-shaped carrier. After forming, dry at 120℃ for 4 hours and calcine at 650℃ for 4 hours to obtain catalyst carrier A.

[0055] An impregnation solution containing molybdenum and cobalt was prepared, wherein the molybdenum source was ammonium molybdate and the cobalt source was cobalt nitrate. The molybdenum content in the impregnation solution, calculated as molybdenum oxide, was 8.4 g / 100 mL, and the cobalt content, calculated as cobalt oxide, was 2.0 g / 100 mL. The carrier A was impregnated with the above-mentioned impregnation solution containing molybdenum and cobalt using a saturated impregnation method. After impregnation, the carrier A was dried at 120°C for 4 hours and calcined at 500°C for 4 hours to obtain the catalytic cracking slurry hydrogenation catalyst A of the present invention.

[0056] Example 2

[0057] Compared to Example 1, the difference lies in the preparation process of the alumina dry gel: 80 grams of alumina trihydrate, 100 grams of boehmite, and 5 grams of aluminum sulfate were added to 250 grams of purified water and ground using a ball mill. This yielded the carrier B and the catalytic cracking slurry hydrogenation catalyst B of the present invention.

[0058] Example 3

[0059] Compared with Example 1, the difference lies in the fact that during the preparation of the alumina dry adhesive, 900 grams of purified water were added to the ground slurry and stirred, followed by the addition of 3.0 grams of sodium hydroxide, 3 grams of sodium hexametaphosphate, and 12 grams of water glass, resulting in a slurry pH of 9.57. This yields the carrier C and the catalytic cracking slurry hydrogenation catalyst C of the present invention.

[0060] Example 4

[0061] Compared to Example 1, the difference lies in the preparation process of the alumina dry gel: 1100g of purified water was added to the ground slurry and stirred, followed by 5.5g of sodium hydroxide, 3g of sodium hexametaphosphate, and 16g of silica sol, resulting in a slurry pH of 9.35. This yields the carrier D of the present invention and the catalyst D for the hydrogenation of catalytic cracking oil slurry.

[0062] Example 5

[0063] Compared to Example 1, the difference lies in the preparation process of the alumina dry gel: 1100g of purified water was added to the ground slurry and stirred, followed by 5.5g of sodium hydroxide, 8g of disodium ethylenediaminetetraacetate, and 16g of silica sol, resulting in a slurry pH of 9.71. This yields the carrier E of the present invention and the catalyst E for the hydrogenation of catalytic cracking oil slurry.

[0064] Example 6

[0065] Compared to Example 1, the difference lies in that the slurry after stirring during the preparation of the alumina dry gel is transferred to a high-pressure reactor for hydrothermal treatment at a temperature of 240°C for 5 hours. This yields the carrier F of the present invention and the catalyst F for the hydrogenation of catalytic cracking oil slurry.

[0066] Example 7

[0067] Compared to Example 1, the difference lies in the addition of 5 grams of lauryl alcohol polyoxyethylene ether to the ground slurry during the preparation of the alumina dry adhesive. This yields the carrier G of the present invention and the catalyst G for the hydrogenation of catalytic cracking slurry.

[0068] Comparative Example 1

[0069] Compared to Example 1, the difference lies in the use of commercially available macroporous pseudo-hydroaluminate (DGA) for the kneading and molding of alumina dry adhesive. After molding, the mixture was dried at 120°C for 4 hours and calcined at 850°C for 4 hours. An active metal solution was prepared, containing 11.44 g / 100 mL of molybdenum oxide and 2.72 g / 100 mL of cobalt oxide. Comparative support DA and comparative catalytic cracking slurry hydrogenation catalyst DA were thus obtained.

[0070] Comparative Example 2

[0071] Similar to Example 1, except that when preparing the active metal solution, the content of molybdenum oxide in the solution is 8.4 g / 100 mL and the content of nickel oxide is 2.0 g / 100 mL, thus preparing the comparative catalytic cracking slurry hydrogenation catalyst DB.

[0072] Comparative Example 3

[0073] Compared with Example 1, the difference lies in that 100g of alumina trihydrate and 100g of boehmite were added to 250g of purified water and ground using a ball mill; when preparing the active metal solution, the content of molybdenum oxide in the solution was 12.13g / 100mL, and the content of cobalt oxide was 2.89g / 100mL. Comparative support DC and comparative catalytic cracking slurry hydrogenation catalyst DC were obtained.

[0074] Comparative Example 4

[0075] Compared with Example 1, the difference lies in that 1100g of purified water was added to the ground slurry and stirred, followed by the addition of 5.5g of sodium hydroxide and 12g of water glass; when preparing the active metal solution, the content of molybdenum oxide in the solution was 11.84g / 100mL, and the content of cobalt oxide was 2.82g / 100mL. Comparative support DD and comparative catalytic cracking slurry hydrogenation catalyst DD were thus obtained.

[0076] Comparative Example 5

[0077] Compared to Example 1, the difference lies in that 1100g of purified water was added to the ground slurry and stirred, followed by the addition of 11g of sodium hydroxide, 3g of sodium hexametaphosphate, and 12g of water glass, resulting in a slurry pH of 13.67. When preparing the active metal solution, the molybdenum oxide content was 20.55g / 100mL, and the cobalt oxide content was 4.89g / 100mL. Comparative support DE and comparative catalytic cracking slurry hydrogenation catalyst DE were thus obtained.

[0078] Tables 1, 2, and 3 list the properties of the supports and catalysts prepared in the above examples and comparative examples, respectively.

[0079] Table 1. Properties of catalyst supports in each example and comparative example.

[0080]

[0081] Table 2 Properties of catalyst supports obtained from each comparative example

[0082] <![CDATA[Mass percentage of the additive SiO2 in alumina, %]]> 0 2.93 2.87 2.87 - <![CDATA[Pore volume, cm 3 / g]]> 0.80 0.60 0.72 0.38 0.83 <![CDATA[Specific surface area, m 2 / g]]> 154 230 211 330 142 Most probable aperture, nm 12.5 9.0 12.5 4.5 17.5 Aperture concentration range, nm 5～17.5 4～17.5 7～25 - 7～25 The concentrated aperture size occupies a percentage of the total pore volume, % 84 76 79 - 82

[0083] *Note: All the carriers obtained in each comparative example are single-peaked.

[0084] Table 3. Composition and properties of catalysts in each example and comparative example.

[0085] A 8.78 2.09 - 1.07 151 B 8.79 2.09 - 1.10 145 C 8.78 2.09 - 1.02 161 D 8.78 2.09 - 1.05 153 E 8.78 2.09 - 1.03 142 F 8.79 2.10 - 1.13 143 G 8.78 2.09 - 1.08 152 DA 8.78 2.09 - 0.70 134 DB 8.78 - 2.09 1.07 152 DC 8.79 2.09 - 0.51 210 DD 8.79 2.10 - 0.61 190 DE 8.78 2.09 - 0.29 308 FZC-28 8.92 - 2.21 0.68 137

[0086] Catalyst evaluation

[0087] The catalysts prepared in Examples 1-7 and Comparative Examples 1-5, along with a conventional residue hydrodemetallizing agent (brand name FZC-28), were taken in equal volumes and loaded into the catalytic cracking slurry hydrotreating reactor between the hydroprotective agent and the hydrodesulfurization catalyst. Other catalysts were identical (i.e., the catalysts loaded from top to bottom in a volume ratio of 2:2:6 were, in order: hydroprotective agent (FZC-12A), hydrotreating transition agent from the examples or comparative examples, or conventional hydrodemetallizing catalyst (brand name FZC-28), and hydrodesulfurization catalyst (brand name FZC-33B)). The catalyst sulfidation was performed using a wet sulfidation process, with dimethyl disulfide (DMDS) as the sulfiding agent. The sulfiding oil was straight-run diesel, with the sulfiding agent accounting for 1.5% of the straight-run diesel mass. Sulfidation was carried out at a constant temperature of 230°C for 8 hours and then at 320°C for 8 hours. The raw material was a full-fraction oil slurry with a sulfur content of 2.15 wt% and a density (20℃) of 1.125 g / cm³. 3 The (tri- and tetra-cyclic) aromatic hydrocarbon content was 52.1%. Process conditions: reaction pressure 6.0 MPa, reaction temperature 340℃, hydrogen-to-oil volume ratio 1000, liquid hourly space velocity 0.5 h⁻¹. -1 The results of hydrotreated catalytic cracking slurry obtained after 200 hours of operation are listed in Tables 4 and 5, and the results of hydrotreated catalytic cracking slurry obtained after 1500 hours of operation are listed in Tables 6 and 7.

[0088] Table 4 Evaluation results of catalysts in each example

[0089] <![CDATA[Density (20 °C) / g·cm -3 > 1.070 1.071 1.067 1.069 1.068 1.072 1.070 Desulfurization rate, % 78.6 78.4 79.0 78.8 78.9 78.2 78.7 Ideal aromatics retention rate, % 87.2 87.4 86.6 87.0 86.8 87.6 87.1

[0090] Table 5 Evaluation results of each comparative catalyst

[0091] <![CDATA[Density (20 °C) / g·cm -3 > 1.079 1.075 1.075 1.076 1.086 1.084 Desulfurization rate, % 76.0 76.9 76.9 76.6 73.6 74.3 Ideal aromatics retention rate, % 87.6 84.7 87.1 87.4 88.6 85.3

[0092] Table 6 Evaluation results of catalysts in each example

[0093] <![CDATA[Density (20 °C) / g·cm -3 > 1.073 1.074 1.070 1.072 1.071 1.075 1.073 Desulfurization rate, % 76.3 76.1 76.7 76.5 76.6 75.9 76.4 Ideal aromatics retention rate, % 87.4 87.6 86.8 87.2 87.0 87.8 87.3

[0094] Table 7 Evaluation results of each comparative catalyst

[0095] <![CDATA[Density (20 °C) / g·cm -3 > 1.084 1.078 1.081 1.080 1.091 1.087 Desulfurization rate, % 69.4 73.9 71.4 73.2 64.7 68.9 Ideal aromatics retention rate, % 88.0 84.9 87.7 88.2 89.8 85.6

[0096] In Table 4-7, the aromatic hydrocarbon retention rate is the percentage of the mass content of tricyclic and tetracyclic aromatic hydrocarbons in the hydrogenation product relative to the mass content of tricyclic and tetracyclic aromatic hydrocarbons in the feedstock. Among them, tricyclic and tetracyclic aromatic hydrocarbons are ideal feedstock aromatic hydrocarbons for the preparation of high-end carbon-based materials such as needle coke, i.e., ideal aromatic hydrocarbons, and the aromatic hydrocarbon retention rate is the ideal aromatic hydrocarbon retention rate.

[0097] As can be seen from Tables 4-7, compared with the contrast agent and conventional hydrogenation catalysts, the hydrogenation transition agent prepared using the support of this invention, combined with the original catalyst gradation, results in a slower decline in the activity of the catalyst system. The catalyst system exhibits better desulfurization selectivity and activity stability, and also has a greater retention rate for tricyclic and tetracyclic aromatic hydrocarbons.

[0098] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. The application of a catalytic slurry hydrotreating catalyst in the preparation of needle coke feedstock during the hydrotreating process of catalytic cracking slurry oil, wherein the catalytic slurry hydrotreating catalyst is packed between a hydrotreating protective agent and a hydrodesulfurization catalyst; wherein, The catalytic slurry hydrogenation catalyst comprises an alumina support containing promoters, MoO3, and CoO. The support has a bimodal pore size distribution, with smaller pores concentrated in the 10–40 nm range, accounting for 20%–40% of the total pore volume. Larger pores are concentrated in the 150–400 nm range, accounting for 30%–50% of the total pore volume. The support has the following properties: pore volume of 0.95–1.35 cm³. 3 / g, specific surface area is 110~175m² 2 / g; Based on the mass of the hydrogenation catalyst, the content of MoO3 is 4.0%~10.0%, and the content of CoO is 0.8%~2.5%; In the alumina carrier containing additives, the additives are one or more of fluorine, phosphorus, silicon, or boron.

2. The application according to claim 1, characterized in that, The properties of the carrier containing the additives include: a pore volume of 1.00~1.25 cm³. 3 / g; and / or, with a specific surface area of ​​130~170m² 2 / g.

3. The application according to claim 1, characterized in that, In the alumina carrier containing additives, the content of the additives, calculated as oxides, accounts for 0.2% to 10% of the total mass of alumina in the carrier; And / or, the catalytic slurry hydrogenation catalyst is clover-shaped.

4. The application according to claim 1, characterized in that, In the alumina carrier containing the additive, the additive is silicon.

5. The application according to claim 3, characterized in that, In the alumina carrier containing additives, the content of the additives, calculated as oxides, accounts for 1% to 6% of the total mass of alumina in the carrier.

6. The application according to any one of claims 1-5, characterized in that, The preparation method of the catalytic slurry hydrogenation catalyst includes the following steps: a) Mix the first aluminum source, the second aluminum source and the third aluminum source with water to obtain a slurry, and then grind the slurry; b) Add purified water to the slurry obtained in step a) and stir; c) Add pH adjuster, modifier, auxiliary agent precursor and optional dispersant to the material obtained in step b) to obtain a mixed slurry, and then perform hydrothermal treatment on the mixed slurry; d) The material obtained in step c) is dried to obtain alumina dry adhesive; e) Mix the alumina dry adhesive obtained in step d) with the binder, shape, dry, and calcine to obtain the carrier; f) Impregnate the support obtained in step e) with an impregnation solution containing molybdenum and cobalt, and then dry and calcine to obtain the hydrogenation catalyst.

7. The application according to claim 6, characterized in that, In step a), the first aluminum source is alumina trihydrate; the second aluminum source is alumina dry gel with a water content of less than 35% by mass fraction; and the third aluminum source is an aluminum-containing salt compound.

8. The application according to claim 7, characterized in that, In step a), the second aluminum source is aluminum oxide monohydrate; the third aluminum source is at least one of aluminum nitrate, aluminum chloride, aluminum sulfate, and sodium aluminate.

9. The application according to claim 6, characterized in that, In step a), the mass ratio of the first aluminum source, the second aluminum source, and the third aluminum source is 30~66:33~60:1~10; and / or, in step a), the amount of water added is 100%~150% of the total mass of the first aluminum source, the second aluminum source, and the third aluminum source.

10. The application according to claim 6, characterized in that, In step a), the slurry is ground until the particle size in the slurry is 4~20µm, calculated as the median particle size D50.

11. The application according to claim 6, characterized in that, In step b), the slurry obtained in step a) is mixed with purified water so that the total mass of the first aluminum source, the second aluminum source and the third aluminum source in the slurry is 10% to 20%.

12. The application according to claim 6, characterized in that, In step c), the pH value of the mixed slurry in step c) is controlled to be within the range of 9.0 to 12.

5.

13. The application according to claim 6, characterized in that, In step c), the dispersant is a nonionic surfactant with an HLB value of 10-20; the amount of the dispersant added is less than 10% of the mass of the material obtained in step b).

14. The application according to claim 13, characterized in that, In step c), the dispersant is at least one of Tween-80, lauryl alcohol polyoxyethylene ether, and methyl glucose polyoxyethylene ether; the amount of the dispersant added is 0.01% to 10% of the mass of the material obtained in step b).

15. The application according to claim 6, characterized in that, The modifier is at least one of sodium hexametaphosphate, sodium tripolyphosphate, disodium ethylenediaminetetraacetate, sodium gluconate, and sodium tartrate; the amount of the modifier added is 0.01% to 10% of the mass of the material obtained in step b).

16. The application according to claim 6, characterized in that, In step c), the fluorine precursor is at least one of hydrofluoric acid, ammonium fluoride, boron trifluoride, and sodium fluorosilicate; the phosphorus precursor is at least one of phosphoric acid, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate; the silicon precursor is at least one of silica sol, water glass, and fluorosilicic acid; and the boron precursor is at least one of boric acid, sodium borate, ammonium borate, and ammonium metaborate.

17. The application according to claim 6, characterized in that, In step c), the hydrothermal treatment conditions are as follows: temperature is 200~260℃, and hydrothermal time is 4~10 hours.

18. The application according to claim 6, characterized in that, In step d), the drying conditions are as follows: drying temperature is 100~180℃, drying time is 4~12 hours.

19. The application according to claim 6, characterized in that, In step e), the drying temperature after molding is 100~180℃, and the drying time is 4~12 hours; the calcination temperature after molding is 500~800℃, and the calcination time is 3~12 hours.

20. The application according to claim 6, characterized in that, In step f), the drying conditions after impregnation are as follows: drying temperature is 100~180℃, drying time is 4~12 hours; the calcination conditions are as follows: calcination temperature is 450~600℃, calcination time is 3~6 hours.

Images