Catalytic oil slurry hydrogenation protectant and preparation method thereof

Abstract

The application discloses a catalytic cracking slurry oil hydrogenation protective agent and a preparation method thereof. The hydrogenation protective agent comprises a carrier and hydrogenation active metal, wherein the carrier is alumina, the hydrogenation active metal comprises molybdenum oxide and cobalt oxide, and the alumina carrier has the following properties: the most probable pore diameter is 40-100 nm, preferably 50-70 nm, and the pore volume of the pore with a diameter of (the most probable pore diameter-30) nm to (the most probable pore diameter+30) nm accounts for more than 75% of the total pore volume. The hydrogenation protective agent adopts the alumina carrier with a suitable pore diameter and a suitable large-pore pore volume ratio, can eliminate the diffusion resistance of macromolecules in the process of adsorption on the surface of the catalyst and reaction of catalytic cracking slurry oil hydrogenation, and is beneficial to the hydrogenation reaction.

Description

Technical Field

[0001] This invention belongs to the field of hydrogenation technology, and specifically relates to a catalytic slurry hydrogenation protective agent 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. However, 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 very 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 processing with conventional residue hydrotreating catalysts results in excessive aromatic loss. Currently, there is limited research on hydrogenation catalysts specifically for catalytic cracking slurry oil. Therefore, developing a catalyst suitable for hydrogenation of catalytic cracking slurry oil is of great significance.

[0004] CN103013567A discloses a method for producing needle coke feedstock from catalytic cracking slurry. This 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 hydroprotective 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 heater. After heating, it enters the hydrotreating reaction zone for hydrotreating. The hydroprotective agent is Raschig ring-shaped and is a conventional residue hydroprotective agent. However, for catalytic cracking slurry feedstock, the pore volume of the hydroprotective agent in the above method is relatively small. During the hydrotreating reaction, continuous coke deposition easily causes pore blockage, covering of active sites, and rapid catalyst activity decay, ultimately leading to unit shutdown.

[0005] 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

[0006] To address the shortcomings of existing technologies, this invention provides a protective agent for the hydrotreating of catalytic cracking slurry oil and its preparation method. This hydrotreating protective agent has a suitable pore size and a suitable proportion of large-pore volume, which can eliminate the diffusion resistance of macromolecules adsorbing and reacting on the catalyst surface during the hydrotreating process of catalytic cracking slurry oil, thus facilitating the hydrotreating reaction.

[0007] The hydrotreating protectant for catalytic cracking slurry hydrotreating is placed in the upper layer of the catalytic cracking slurry hydrotreating reactor, receiving the separated and deconsolidated catalytic cracking slurry. The deconsolidated catalytic cracking slurry has a high content of gums and asphaltenes (4.0%–15.0%). Asphaltenes molecules are mainly composed of 5 to 7 lamellar fused aromatic rings with a size of 12–16 angstroms (1.2–1.6 nm), and these molecules are prone to aggregation. The inventors discovered that developing a hydrotreating protectant with suitable large pore size and distribution can eliminate the diffusion resistance of large asphaltenes during adsorption and reaction on the catalyst surface, thus facilitating the hydrotreating reaction. Simultaneously, the slurry contains a large amount of coking material; the hydrotreating protectant, with its large pore size, can not only accommodate more coke deposits but also ensure that many active sites remain uncovered by coke even after prolonged operation. This plays a crucial role in protecting the performance of the downstream catalyst from the influence of coke and other impurities, thereby guaranteeing the long-term operation of the unit.

[0008] The first aspect of this invention provides a catalytic cracking slurry hydrotreating protectant, comprising a support and a hydrotreating active metal, wherein an alumina support is used, and the hydrotreating active metal comprises molybdenum oxide and cobalt oxide. The properties of the alumina support are as follows: the most probable pore size is 40-100 nm, preferably 50-70 nm, and the pore volume occupied by channels from (most probable pore size - 30) nm to (most probable pore size + 30) nm accounts for more than 75% of the total pore volume, preferably 75%-90%.

[0009] In this invention, the alumina support has a single peak from (most probable pore size - 30) nm to (most probable pore size + 30) nm, with a peak width of at least 60 nm.

[0010] In this invention, based on the mass of the hydrogenation protectant, the mass content of MoO3 is 2.0% to 7.0%, and the mass content of CoO is 0.3% to 1.7%.

[0011] In this invention, based on the mass of the hydrogenation protective agent, the mass content of the alumina carrier is 91.3% to 97.7%.

[0012] In this invention, the pore volume of the alumina carrier is 1.00–1.40 cm³. 3 / g, preferably 1.10~1.30cm 3 / g.

[0013] In this invention, the specific surface area of ​​the alumina carrier is 120–180 m². 2 / g, preferably 130-170m 2 / g.

[0014] In this invention, the catalyst is preferably in the shape of a four-leaf impeller or a clover shape.

[0015] A third aspect of the present invention provides a method for preparing the above-mentioned hydrogenation protective agent, comprising the following steps:

[0016] a) The first aluminum source, the second aluminum source and the third aluminum source are mixed with water to obtain a slurry, and then the slurry is ground.

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

[0018] c) Add modifier, pH adjuster 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 carrier obtained in step e) with an impregnation solution containing molybdenum and cobalt, and then dry and calcine to obtain the hydrogenation protectant.

[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 value of the mixed slurry in step c) to be 8.5 to 12.0.

[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 6% of the mass of the material obtained in step b), for example, 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 the present invention, in step c), the hydrothermal treatment conditions are as follows: temperature is 220-280℃, and time is 5-12 hours.

[0032] In the method of this invention, in step d), before drying, the material obtained in step c) can be subjected to steps such as filtration and washing. Conventional filtration and washing methods are sufficient. The drying conditions are as follows: drying temperature is 100–180℃, and drying time is 4–10 hours.

[0033] 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.

[0034] 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).

[0035] 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.

[0036] In the method of the present invention, in step e), the shaped material can be a four-leaf stalk or a four-leaf clover.

[0037] In the method of this invention, in step e), the drying conditions after molding are as follows: drying temperature is 100–180°C, and drying time is 4–12 hours; the calcination conditions after molding are as follows: calcination temperature is 500–800°C, and calcination time is 3–12 hours. The calcination atmosphere can be an oxygen-containing gas, such as air.

[0038] In the method of this invention, in step f), the impregnation solution containing molybdenum and cobalt contains cobalt at a concentration of 0.2–1.6 g / 100 mL (calculated as cobalt oxide) and molybdenum at a concentration of 1.6–6.3 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.

[0039] In the method of the present invention, in step f), the impregnation is preferably carried out by saturation impregnation.

[0040] 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.

[0041] The hydrogenation protectant of this invention is suitable for hydrotreating catalytic cracking slurry oil, and is particularly suitable for filling the upper layer of the catalytic cracking slurry hydrotreating unit. It is mainly used as a hydrogenation protectant to protect the downstream main hydrogenation catalyst and provide a guarantee for the long-term operation of the catalytic cracking slurry hydrotreating unit.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. In existing technologies, catalytic cracking slurry and residue oil are similar, both containing gums and asphaltenes. However, catalytic cracking slurry and residue oil have different properties. Catalytic cracking slurry has a lower metal content, and catalyst deactivation is mainly due to coke deposition. The operating cycles of catalytic cracking slurry hydrotreating units and residue oil hydrotreating units differ; catalytic cracking slurry hydrotreating units generally operate for two years, while residue oil hydrotreating units operate for about one year. Under different feedstocks and operating modes, hydrotreating protectants with as many large pores as possible can accommodate more coke deposits, protect downstream catalysts, extend catalyst life, and ensure long-term operation of the unit. This invention provides a hydrotreating protectant suitable for catalytic cracking slurry hydrotreating, wherein the carrier used has a large pore size. Mercury porosimetry shows that the probable pore size of the carrier is 40–100 nm, and the pore size distribution is relatively concentrated, with the pore volume in the range of (probable pore size - 30) nm to (probable pore size + 30) nm accounting for more than 75% of the total pore volume of the carrier. The hydrogenation protective agent carrier of this invention has a suitable large pore size and a suitable pore volume ratio, which can 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 more carbon deposits, which is beneficial to the long-term operation of the hydrogenation unit.

[0044] 2. In the preparation of the hydrogenation protective agent carrier of the present invention, three different aluminum sources are used, the pH value is controlled, a modifier is added, and then hydrothermal treatment is carried out. During the hydrothermal treatment, different aluminum sources form different precursor particles, which then undergo a rehydration reaction. The resulting alumina dry gel does not require the addition of additional pore-forming materials such as pore expanders. It can be obtained by calcining at a relatively low temperature (below 800℃) to produce the hydrogenation protective agent carrier of the present invention with a suitable large pore size and a suitable large pore volume ratio.

[0045] 3. The present invention uses molybdenum and cobalt as active metals to prepare the hydroprotectant. The prepared hydroprotectant not only has high desulfurization selectivity, but also can retain tricyclic and tetracyclic aromatics in catalytic cracking slurry to a great extent, providing ideal raw materials for the preparation of high-end carbon-based materials such as needle coke.

[0046] Detailed Implementation Methods

[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, catalyst, and alumina support and catalyst prepared in Comparative Examples 1, 2, and 4, as well as the conventional residue hydroprotectant 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 supports prepared in Comparative Examples 3 and 5 were measured using a low-temperature liquid nitrogen adsorption method with an ASAP2420 pore structure analyzer from Micron Technology, USA.

[0051] The specific surface areas 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 were obtained by low-temperature liquid nitrogen adsorption method using an ASAP2420 pore structure analyzer from Micron Technology, USA.

[0052] Example 1

[0053] Take 100g of alumina trihydrate, 100g of alumina monohydrate, and 15g of sodium aluminate, add 300g of purified water, and grind using a ball mill at 500rpm for 1 hour. The particle size distribution (D50) in the slurry is 6.05μm. Add another 1000g of purified water to the ground slurry and stir. Then add 2g of acetic acid, 5g of sodium hexametaphosphate, and 10g of Tween-80, bringing the pH of the slurry to 8.93. Transfer the stirred slurry to an autoclave for hydrothermal treatment at 260℃ for 8 hours. Filter and wash the hydrothermally treated material, then dry it at 120℃ for 5 hours to obtain alumina dry gel.

[0054] Take 100g of the prepared alumina dry adhesive, add 1g of guar gum powder, 2g of methylcellulose, 0.5g of acetic acid, and 130g of purified water, knead and shape into a four-leaf wheel-shaped carrier. After shaping, dry at 120℃ for 4 hours and calcine at 700℃ for 4 hours to obtain hydrogenated protective agent 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 3.16 g / 100 mL, and the cobalt content, calculated as cobalt oxide, was 0.74 g / 100 mL. The hydrogenation protectant carrier A was impregnated with the above-mentioned molybdenum and cobalt-containing impregnation solution using a saturated impregnation method. After impregnation, the carrier was dried at 120°C for 4 hours and calcined at 500°C for 4 hours to obtain the catalytic cracking slurry hydrogenation protectant A of this invention.

[0056] Example 2

[0057] Compared to Example 1, the difference lies in the preparation process of the alumina dry gel: 100g of alumina trihydrate, 85g of alumina monohydrate, and 15g of sodium aluminate were added to 300g of purified water and ground using a ball mill. This yielded the hydrogenation protective agent carrier B and the catalytic cracking slurry hydrogenation protective agent B of the present invention.

[0058] Example 3

[0059] Compared with Example 1, the difference lies in the preparation process of the alumina dry gel. 100g of alumina trihydrate, 100g of alumina monohydrate, and 10g of aluminum sulfate were added to 300g of purified water and ground using a ball mill. Then, 1000g of purified water was added to the ground slurry, stirred, and followed by the addition of 8g of sodium hydroxide, 5g of sodium hexametaphosphate, and 10g of Tween-80. The pH of the slurry was 9.14. This yielded the hydrogenation protective agent carrier C and the catalytic cracking slurry hydrogenation protective agent C of this invention.

[0060] Example 4

[0061] Compared to Example 1, the difference lies in the preparation process of the alumina dry adhesive, where 900 grams of purified water are added to the ground slurry and stirred, followed by the addition of 2 grams of acetic acid and 9 grams of sodium hexametaphosphate. This yields the hydrogenation protective agent carrier D and the catalytic cracking slurry hydrogenation protective agent D of the present invention.

[0062] Example 5

[0063] Compared to Example 1, the difference lies in that the slurry after stirring during the preparation of the alumina dry adhesive is transferred to a high-pressure reactor for hydrothermal treatment at a temperature of 270°C for 7 hours. This yields the hydrogenation protective agent carrier E and the catalytic cracking slurry hydrogenation protective agent E of the present invention.

[0064] Example 6

[0065] Compared with Example 1, the difference lies in that the prepared alumina dry adhesive is kneaded and molded, then dried at 120°C for 4 hours and calcined at 750°C for 4 hours. This yields the hydrogenation protective agent carrier F and the catalytic cracking slurry hydrogenation protective agent F of the present invention.

[0066] Comparative Example 1

[0067] Similar to Example 1, except that when using alumina dry adhesive for kneading and molding, commercially available large-pore pseudo-thin water alumina is used. After molding, it is dried at 120°C for 4 hours and calcined at 900°C for 4 hours to obtain carrier DA.

[0068] An active metal solution was prepared, containing 4.37 g / 100 mL of molybdenum oxide and 1.02 g / 100 mL of cobalt oxide. The impregnation carrier was prepared using a conventional saturated impregnation method. After impregnation, the carrier was dried at 120 °C for 4 hours and then calcined at 500 °C for 4 hours to obtain the comparative hydrogenation protectant DA.

[0069] Comparative Example 2

[0070] Similar to Example 1, except that the active metal solution was prepared with a molybdenum oxide content of 3.16 g / 100 mL and a nickel oxide content of 0.74 g / 100 mL. The impregnation was performed using a conventional saturated impregnation method. After impregnation, the solution was dried at 120°C for 4 hours and calcined at 500°C for 4 hours to obtain the comparative hydrogenation protectant DB.

[0071] Comparative Example 3

[0072] Compared with Example 1, the difference is that 100g of alumina trihydrate and 100g of alumina monohydrate were added to 300g of purified water and ground using a ball mill to obtain carrier DC. The carrier DC was then impregnated with active metals. The molybdenum oxide content in the solution was 4.63g / 100mL and the cobalt oxide content was 1.08g / 100mL, thus preparing the comparative hydrogenation protective agent DC.

[0073] Comparative Example 4

[0074] Compared with Example 1, the difference is that 1000g of purified water was added to the ground slurry and stirred, followed by 2g of acetic acid and 10g of Tween-80 to obtain the carrier DD. The carrier DD was then impregnated with active metals. The molybdenum oxide content in the solution was 4.14g / 100mL and the cobalt oxide content was 0.96g / 100mL, thus preparing the comparative hydrogenation protective agent DD.

[0075] Comparative Example 5

[0076] Compared with Example 1, the difference is that 1000g of purified water was added to the ground slurry and stirred, followed by 6g of nitric acid and 10g of Tween-80. The pH of the slurry was 1.93, resulting in a carrier DE. The carrier DE was then impregnated with active metals, and the content of molybdenum oxide in the solution was 7.87g / 100mL, and the content of cobalt oxide was 1.83g / 100mL, thus preparing the comparative hydrogenation protective agent DE.

[0077] Tables 1, 2 and 3 list the properties of the supports and catalysts prepared in the above examples and comparative examples, wherein the pore distribution shows a single peak from (most probable pore diameter - 30) nm to (most probable pore diameter + 30) nm with a peak width of at least 60 nm.

[0078] Table 1. Pore properties of the catalyst supports obtained in each example.

[0079]

[0080] Table 2. Pore properties of catalyst supports obtained from each comparative example.

[0081] <![CDATA[Pore volume, cm 3 / g]]> 0.83 0.61 0.76 0.43 0.85 <![CDATA[Specific surface area, m 2 / g]]> 149 221 187 240 123 Most probable aperture, nm 12.5 9 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, % 86 78 82 - 86

[0082] Table 3. Composition and properties of catalysts in each example and comparative example.

[0083] A 3.74 0.87 1.17 149 B 3.74 0.87 1.12 155 C 3.76 0.89 1.18 147 D 3.75 0.87 1.15 152 E 3.74 0.87 1.24 138 F 3.74 0.88 1.20 143 DA 3.74 0.87 0.78 130 DB 3.75 0.87(NiO) 1.16 148 DC 3.74 0.87 0.59 210 DD 3.73 0.87 0.71 176 DE 3.74 0.86 030 227 FZC-12A 3.80 0.91(NiO) 0.73 113

[0084] Catalyst evaluation

[0085] The catalysts prepared in Examples 1-6 and Comparative Examples 1-5, along with a conventional residue hydrotreating protectant (brand name FZC-102), were loaded in equal volumes into the upper layer of the hydrotreating protectant in the catalytic cracking slurry hydrotreating reactor. Other catalysts were the same (i.e., the catalysts loaded from top to bottom in a volume ratio of 2:2:6 were, in order, hydrotreating protectant, hydrodemetallization 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 feedstock was whole-fraction slurry oil with a sulfur content of 0.96 wt% and a density (20°C) of 1.096 g / cm³. 3 The (tri- and tetra-cyclic) aromatic hydrocarbon content was 57.2%. Process conditions: reaction pressure 6.0 MPa, reaction temperature 350℃, hydrogen-to-oil volume ratio 1000, liquid hourly space velocity 0.8 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.

[0086] Table 4 Evaluation results of catalysts in each example

[0087] <![CDATA[Density of hydrogenation product (20℃), g / cm 3 > 1.050 1.048 1.051 1.049 1.053 1.052 Desulfurization rate, % 58.5 58.9 58.4 58.7 58.1 58.3 (Tricyclic + Tetracyclic) Aromatic Retention Rate, % 94.3 94.0 94.5 94.2 94.8 94.6

[0088] Table 5 Evaluation results of each comparative catalyst

[0089] <![CDATA[Density of hydrogenation product (20°C), g / cm 3 > 1.056 1.052 1.051 1.054 1.065 1.062 Desulfurization rate, % 55.5 57.5 57.6 57.4 53.1 54.8 (Tricyclic + Tetracyclic) Aromatic Retention Rate, % 92.2 91.2 91.1 91.4 93.2 92.5

[0090] Table 6 Evaluation results of catalysts in each example

[0091] <![CDATA[Density of hydrogenation product (20℃), g / cm 3 > 1.053 1.051 1.054 1.052 1.056 1.055 Desulfurization rate, % 56.0 56.4 55.9 56.2 55.6 55.8 (Tricyclic + Tetracyclic) Aromatic Retention Rate, % 94.5 94.2 94.7 94.4 95.0 94.8

[0092] Table 7 Evaluation results of each comparative catalyst

[0093]

[0094] 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 raw material 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.

[0095] As can be seen from Tables 4-7, compared with the contrast agent and conventional hydrogenation protectant, the hydrogenation protectant prepared using the carrier of this invention, combined with the original catalyst gradation, results in a slower decay of catalyst activity, better desulfurization activity selectivity and stability, and a greater retention rate for tricyclic and tetracyclic aromatic hydrocarbons.

[0096] 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 cracking slurry hydrotreating protectant in the preparation of needle coke feedstock through catalytic cracking slurry hydrotreating, wherein the hydrotreating protectant comprises a support and a hydrotreating active metal, wherein, An alumina support is used, and the hydrogenation active metals include molybdenum oxide and cobalt oxide. The properties of the alumina support are as follows: the most probable pore size is 40~100 nm, and the pore volume occupied by channels from (most probable pore size - 30) nm to (most probable pore size + 30) nm accounts for more than 75% of the total pore volume; the properties of the support are as follows: pore volume is 1.00~1.40 cm³. 3 / g, specific surface area is 120~180m² 2 / g; Based on the mass of the hydrogenation protectant, the mass content of MoO3 is 2.0%~7.0%, and the mass content of CoO is 0.3%~1.7%.

2. The application according to claim 1, characterized in that, The properties of the alumina carrier are as follows: the most probable pore size is 50~70nm, and the pore volume occupied by channels from (most probable pore size - 30)nm to (most probable pore size + 30)nm accounts for 75%~90% of the total pore volume.

3. The application according to claim 1, characterized in that, The carrier has the following properties: pore volume of 1.10~1.30 cm³. 3 / g; and / or, with a specific surface area of ​​130~170m² 2 / g.

4. The application according to claim 1, characterized in that, The hydrogenation protectant is in the shape of a four-leaf wheel or a four-leaf clover.

5. The application according to any one of claims 1-4, characterized in that, The preparation method of the hydrogenation protective agent includes the following steps: a) The first aluminum source, the second aluminum source and the third aluminum source are mixed with water to obtain a slurry, and then the slurry is ground. b) Add purified water to the slurry obtained in step a) and stir; c) Add modifier, pH adjuster 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 carrier obtained in step e) with an impregnation solution containing molybdenum and cobalt, and then dry and calcine to obtain the hydrogenation protective agent; 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. In step c), the modifier is at least one of sodium hexametaphosphate, sodium tripolyphosphate, disodium ethylenediaminetetraacetate, sodium gluconate, and sodium tartrate.

6. The application according to claim 5, 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.

7. The application according to claim 5, 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.

8. The application according to claim 5, characterized in that, 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.

9. The application according to claim 5, 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.

10. The application according to claim 5, 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%.

11. The application according to claim 5, characterized in that, In step c), the pH value of the mixed slurry is controlled to be 8.5~12.

0.

12. The application according to claim 5, characterized in that, In step c), the dispersant is a nonionic surfactant with an HLB value of 10-20.

13. The application according to claim 5, characterized in that, In step c), the dispersant is at least one of Tween-80, lauryl alcohol polyoxyethylene ether, and methyl glucose polyoxyethylene ether.

14. The application according to claim 5, characterized in that, The amount of the modifier added is 0.01% to 6% of the mass of the material obtained in step b); and / or, the amount of the dispersant added is less than 10% of the mass of the material obtained in step b).

15. The application according to claim 14, characterized in that, The amount of dispersant added is 0.01% to 10% of the mass of the material obtained in step b).

16. The application according to claim 5, characterized in that, In step c), the hydrothermal treatment conditions are as follows: temperature is 220~280℃, and time is 5~12 hours.

17. The application according to claim 5, characterized in that, In step d), the drying conditions are as follows: the drying temperature is 100~180℃ and the drying time is 4~10 hours.

18. The application according to claim 5, characterized in that, In step e), the drying conditions after molding are as follows: drying temperature is 100~180℃, drying time is 4~12 hours; the calcination conditions after molding are as follows: calcination temperature is 500~800℃, calcination time is 3~12 hours; and / or, in step f), the impregnation adopts the saturated impregnation method.

19. The application according to claim 18, 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.

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