Preparation and application of multifunctional core-shell structure hydrocracking catalyst

Abstract

The application discloses a multifunctional core-shell structure hydrocracking catalyst and a preparation method and application thereof. The catalyst comprises a mesoporous SiO2 inner core doped with Zr and / or Ce, and a MoS2 and / or WS2 / Al2O3 outer shell coated by atomic layer deposition (ALD). The key lies in introducing ultraviolet ozone (UV / O3) treatment after ALD to strengthen the interface bonding force between the inner core and the outer shell. When the catalyst is used for heavy oil hydrocracking, spatial cooperation of cracking and hydrogenation sites can be realized, and the catalyst has high conversion rate, high diesel selectivity, low coking rate and excellent stability. The application also claims the catalyst product, the preparation method and the application in the hydrocracking of poor heavy oil (such as vacuum residue and shale oil).

Description

Technical Field

[0001] This application belongs to the field of petroleum refining and catalytic materials technology, specifically relating to a core-shell structured catalyst for heavy oil hydrocracking, its preparation method and application, and particularly to a high-performance hydrocracking catalyst with Zr and / or Ce-doped mesoporous silica as the core, atomic layer deposition (ALD) alumina supported on MoS2 / WS2 as the shell, and enhanced core-shell interface bonding by ultraviolet ozone (UV / O3) treatment. Background Technology

[0002] In the oil refining industry, hydrocracking technology is a key process for processing heavy oil, capable of converting low-quality feedstocks such as vacuum residue, shale oil, and cracked oil into high-value-added light fuel oils (such as diesel and jet fuel). With the deterioration of global crude oil quality and increasingly stringent environmental regulations, the market is placing higher demands on catalyst performance: not only must it achieve efficient conversion of heavy oil, but it also needs to improve the selectivity of light oil, reduce hydrogen consumption, and extend catalyst life.

[0003] Currently widely used catalysts mainly include composite molecular sieve catalysts and supported metal catalysts. Composite molecular sieve catalysts provide acidic sites through their microporous-mesoporous composite structure, which can promote the cracking of macromolecules. However, their hydrogenation activity depends on the metal sulfides (such as MoS2 and WS2) supported on their surface. Due to the spatial separation between cracking sites and hydrogenation sites, reaction intermediates (such as olefins and free radicals) need to diffuse over long distances to the hydrogenation sites. During this process, condensation reactions easily occur to form coke, resulting in light oil yields generally below 85% and coking rates exceeding 3%. Supported metal catalysts (such as Mo / Al2O3 and Ni-W / SiO2) have high hydrogenation activity, but they lack acidic sites, have low heavy molecule cracking efficiency (conversion rate <90%), and are prone to sintering and deactivation at high temperatures, resulting in a short service life.

[0004] Core-shell structure design shortens the reaction pathway by spatially separating cracking and hydrogenation sites (e.g., an acidic core and a metal sulfide shell). However, existing technologies still have significant drawbacks: insufficient bonding strength at the core-shell interface, high energy consumption in traditional preparation processes (such as hydrothermal synthesis and high-temperature calcination), and difficulty in forming strong covalent bonds at the inorganic-inorganic interface, leading to easy delamination and deactivation at high temperatures; the catalyst has poor tolerance to high metal content (such as Ni and V) or high-carbon-residue inferior oils, resulting in significant poisoning and deactivation problems. These issues limit the industrial application of core-shell catalysts.

[0005] Therefore, there is an urgent need to develop a novel catalyst that combines a controllable acidic core, a highly dispersed hydrogenation shell, and a robust core-shell interface to synergistically improve conversion rate, selectivity, and lifespan. Summary of the Invention

[0006] According to one aspect of this application, a multifunctional core-shell structured catalyst for heavy oil hydrocracking is provided, characterized in that the catalyst comprises: Core: Composed of mesoporous silicon dioxide doped with metal, wherein the doping metal is selected from at least one of Zr and Ce, and the doping amount is 5% to 15% of the total mass of the core; The outer shell is composed of a transition metal sulfide supported on an alumina carrier, wherein the transition metal sulfide is at least one of MoS2 or WS2; The core of the core-shell structure has a mesopore size of 5-15 nm and an alumina layer thickness of 10-30 nm. The interface between the core and the alumina carrier is treated with ultraviolet ozone to enhance the bonding strength.

[0007] Optionally, the specific surface area of ​​the mesoporous silica core is 400-500 m². 2 / g, total pore volume is 0.5~1.2cm³ 3 / g.

[0008] Optionally, the loading of transition metal sulfides in the outer shell is 5% to 15% of the total mass of the catalyst; Preferably, the loading of transition metal sulfides in the outer shell is 8% to 12% of the total mass of the catalyst.

[0009] Optionally, the preparation method of the core-shell structured catalyst includes the following steps: S1. Prepare a certain amount of cerium source or zirconium source solution. Dissolve hexadecyltrimethylammonium nitrate (CTAB) in a mixed solution of deionized water, ethanol, and diethyl ether in a certain proportion. Then, add a certain amount of ammonia water dropwise, followed by the cerium source or zirconium source solution. Add a silicon source, stir, filter, wash, dry with supercritical CO2, and calcine to obtain Ce / Zr:SiO2. S2. Place the core in the atomic layer deposition (ALD) reaction chamber, use high-purity N2 as the carrier gas, and sequentially introduce trimethylaluminum (TMA) and H2O into the reaction chamber. Nitrogen gas is used to purge between them. By controlling the temperature of the reaction chamber and the number of cycles, an Al2O3-encapsulated core can be obtained. S3. Prepare a solution of ammonium molybdate / ammonium tungstate of a certain concentration, impregnate it on the surface of Al2O3, sonicate it, dry it, and reduce and sulfide it in a tube furnace by introducing a certain proportion of H2 / H2S mixed gas to obtain a core-shell catalyst supported on MoS2 and / or WS2.

[0010] Optionally, in step S1, The silicon source is tetraethyl orthosilicate (TEOS), the zirconium source is zirconium nitrate, and the cerium source is cerium nitrate. The molar ratio of zirconium / cerium to silicon is 1:(10~50); Hexadecyltrimethylammonium nitrate (CTAB) was used as a template agent for hydrolysis and condensation at 40-80℃; The conditions for supercritical CO2 drying were: drying at 40℃ and 10 MPa for 12 h. The calcination conditions were: 550℃ for 4 hours.

[0011] Optionally, in step S2, The carrier gas is high-purity N2, with a flow rate of 100 sccm, and the base pressure of the reaction chamber is 30 Pa; The pulse duration for both TMA and H2O was 20 ms, and the purge time was 10 s. The substrate temperature is 200-300℃, and the number of cycles is 80-240.

[0012] Optionally, in step S3, the ultraviolet ozone treatment is carried out at 120–180°C for 1–3 hours.

[0013] Optionally, in step S4, The molybdenum or tungsten source is ammonium molybdate or ammonium tungstate, with a solution concentration of 0.3–0.7 M; Immerse 1-2 times, with each ultrasonic treatment lasting 20-60 minutes; The vulcanization process adopts a segmented heating program: first, the temperature is increased to 200℃ at 2~5℃ / min and held for 0.5 h, and then the temperature is increased to the target vulcanization temperature at 1~3℃ / min.

[0014] Optionally, the core-shell structured catalyst uses at least one of vacuum residue, shale oil, or cracked oil as the reactant, and the reaction conditions include: reaction temperature: 350~450℃; reaction pressure: 8~20 MPa; hydrogen-to-oil volume ratio: (500~1500):1; and catalyst addition amount: 0.1%~5% of the feedstock mass. The process is carried out in a suspended bed reactor. After the catalyst and feed oil are premixed, they are homogenized by a high-speed shear machine with a shear rate of 200-500 s-1 and a homogenization time of 10-60 min.

[0015] Optionally, in the hydrocracking process, a mixture of CO2 and H2 gas with a volume ratio of 1:(5~20) is periodically introduced during the reaction to remove carbon buildup on the catalyst surface in situ. The injection frequency is once every 24 hours, and each injection lasts for 0.5 to 2 hours; The effective removal of carbon deposits is attributed to the stability of the core-shell structure and the highly dispersed MoS2 / WS2 active sites of the catalyst, which enable CO2 to effectively contact and vaporize the carbon deposits on the surface.

[0016] The beneficial effects that this application can produce include: 1) The core-shell structured catalyst provided in this application achieves spatial matching and functional coupling between the acidic sites (core) and the hydrogenation sites (shell). In the hydrocracking reaction of vacuum residue or cracked oil, the conversion rate is as high as 88.6% to 96.3%, and the diesel yield is 31.6% to 60.9%, which is significantly better than undoped catalysts, catalysts without core-shell structure, or catalysts without interface strengthening.

[0017] 2) The core-shell structure catalyst provided in this application has the characteristics of good cycle stability and low coking rate, with a coking rate as low as 1.2% to 2.6%. At the same time, under the condition of periodically introducing CO2 / H2 mixed gas, the surface carbon can be removed by in-situ gasification, so that the catalyst life is as long as 2000 to 2500 hours, showing excellent cycle stability and industrial application potential.

[0018] 3) The core-shell structure catalyst provided in this application significantly enhances the bonding strength between the core and shell through ultraviolet ozone (UV / O3) treatment. As shown in Tables 1 and 2, compared with Comparative Examples 1 and 4, which were not treated, the catalyst lifespan of this invention (2000-2500 hours) is significantly extended (comparative examples are only 1400-1500 hours), effectively preventing shell detachment or loss of active components during the reaction process, which is a key technical guarantee for achieving long-life operation. Detailed Implementation

[0019] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0020] The specific embodiments of this application are described in detail below. The specific embodiments described herein are for illustration and explanation only, and are not intended to limit this application.

[0021] The analysis method in the embodiments of this application is as follows: In the embodiments of this application, the conversion rate ω, diesel yield μ, coking rate α, and time lifetime t are calculated as follows:

[0022] Where ω represents the reaction conversion rate, m0 represents the initial mass of the reactant oil added, and m1 represents the mass of the unreacted oil after the reaction is completed.

[0023]

[0024] Where μ represents the diesel yield (distillation range 180-410℃), m0 represents the mass of the initially added reactant oil, and m2 represents the mass of the diesel product collected and fractionated after the reaction is completed.

[0025]

[0026] in, The reaction coking rate is represented by m3, the initial mass of the catalyst added is m4, and the mass of the catalyst after the reaction is completed (after solvent extraction to remove adsorbed oil) is m4.

[0027] The time lifetime t represents the time required for the catalyst activity (such as conversion, selectivity) to drop to a set threshold (such as 70% of the initial activity) during continuous operation.

[0028] Example 1 The catalyst prepared in Example 1 is Ce / SiO2 (Ce:Si = 1:10) coated with 8% MoS2 / Al2O3. S1. Dissolve 0.49 g of cerium nitrate in 25 parts of deionized water to form solution A. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts of deionized water, 20 parts of ethanol, and 20 parts of diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 40°C for 4 hours. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40°C and 10 MPa for 12 hours to obtain a white powder. Calcine the powder at 550°C for 4 hours to obtain Ce / SiO2 (Ce:Si molar ratio 1:10, specific surface area 480 m²). 2 / g, total pore volume is 0.92 cm³ 3 / g, average pore size 8 nm).

[0029] S2. A 1.0 g Ce-SiO2 core was placed in the ALD reaction chamber. High-purity N2 was used as the carrier gas to sequentially introduce TMA and H2O into the reaction chamber, with nitrogen purging between them. The N2 carrier gas flow rate was 100 sccm, and the base pressure of the reaction chamber during deposition was 30 Pa. The pulse duration for introducing TMA and H2O was 20 ms, and the purging time was 10 s. The substrate temperature was controlled at 250℃, and the number of cycles was 80, resulting in a dense Al2O3 layer with a thickness of approximately 10 nm. Subsequently, it was activated by ultraviolet ozone treatment (UV / O3) at 120℃ for 1 h to strengthen the interfacial bonding between the core and the alumina shell.

[0030] S3. The Ce / SiO2 coated with Al2O3 is immersed in a 0.4 mol / L ammonium molybdate solution, ultrasonically treated for 30 min, dried at 60℃ for 6 h, and H2 / H2S mixed gas (10:1, flow rate 50 mL / min) is introduced into a tube furnace. The temperature is increased to 200℃ at 2℃ / min and held for 0.5 h. Then, the temperature is increased to 300℃ at 1℃ / min and sulfurized for 3 h to obtain Ce / SiO2 coated with 8% MoS2 / Al2O3.

[0031] Using the above catalyst, vacuum residue hydrocracking was carried out in a slurry bed reactor under the following conditions: temperature 410℃, pressure 14 MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 2 wt%, and shear rate 450 s⁻¹. -1 The homogenization time was 10 min, and a mixture of CO2 and H2 (volume ratio of 1:5) was passed through for 0.5 h every 24 h. The reaction results are shown in Table 1.

[0032] Example 2 The catalyst prepared in Example 2 is Ce / SiO2 coated with 10% MoS2 / Al2O3 (Ce:Si=1:20). S1. Dissolve 0.25 g of cerium nitrate in 25 parts of deionized water to form solution A. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts of deionized water, 20 parts of ethanol, and 20 parts of diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 60°C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40°C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550°C for 4 h to obtain Ce / SiO2 (Ce:Si molar ratio 1:20, specific surface area 490 m²). 2 / g, pore volume 0.95 cm³ 3 / g, pore size 6 nm).

[0033] S2. 1.0 g of Ce-SiO2 core was placed in the ALD reaction chamber. High-purity N2 was used as the carrier gas to sequentially introduce TMA and H2O into the reaction chamber, with nitrogen purging between them. The flow rate of the N2 carrier gas was 100 sccm, and the base pressure of the reaction chamber during deposition was 30 Pa. The pulse duration of both TMA and H2O introduction was 20 ms, and the purging time was 10 s. The substrate temperature was controlled at 200℃, and the number of cycles was 120. After deposition, the Ce / SiO2 core was activated by ultraviolet ozone treatment (UV / O3) at 150℃ for 2 h to obtain 15 nm Al2O3-encapsulated Ce / SiO2.

[0034] S3. The Ce / SiO2 coated with Al2O3 was impregnated in a 0.5 mol / L ammonium molybdate solution twice, and ultrasonically treated for 30 min each time. After drying at 60℃ for 6 h, a H2 / H2S mixed gas (10:1, flow rate 50 mL / min) was introduced into a tube furnace, and the temperature was increased to 200℃ at 3℃ / min and held for 0.5 h. Then, the temperature was increased to 350℃ at 2℃ / min and sulfurized for 4 h to obtain Ce / SiO2 coated with 10% MoS2 / Al2O3.

[0035] Using the above catalyst, vacuum residue hydrocracking was carried out in a slurry bed reactor under the following conditions: temperature 380℃, pressure 12MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 1 wt%, and shear rate 480 s⁻¹. -1 The homogenization time was 30 min, and a mixture of CO2 and H2 (volume ratio of 1:10) was passed through for 1 h every 24 h. The reaction results are shown in Table 1.

[0036] Example 3 The catalyst prepared in Example 3 is Ce / SiO2 coated with 12% MoS2 / Al2O3 (Ce:Si=1:30). S1. Dissolve 0.16 g of cerium nitrate in 25 parts of deionized water to form solution A. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts of deionized water, 20 parts of ethanol, and 20 parts of diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 80°C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40°C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550°C for 4 h to obtain Ce / SiO2 (Ce:Si molar ratio 1:30, specific surface area 470 m²). 2 / g, pore volume 1.05 cm³ 3 / g, pore size 12 nm).

[0037] S2. 1.0 g of Ce-SiO2 core was placed in the ALD reaction chamber. High-purity N2 was used as the carrier gas to sequentially introduce TMA and H2O into the reaction chamber, with nitrogen purging between them. The flow rate of the N2 carrier gas was 100 sccm, and the base pressure of the reaction chamber during deposition was 30 Pa. The pulse duration of both TMA and H2O introduction was 20 ms, and the purging time was 10 s. The substrate temperature was controlled at 300℃, and the number of cycles was 240. After deposition, the Ce / SiO2 core was activated by ultraviolet ozone treatment (UV / O3) at 180℃ for 3 h to obtain 30 nm Al2O3-encapsulated Ce / SiO2.

[0038] S3. The Ce / SiO2 coated with Al2O3 was impregnated twice in a 0.7 mol / L ammonium molybdate solution, sonicated for 30 min each time, dried at 60℃ for 6 h, and then H2 / H2S mixed gas (10:1, flow rate 50 mL / min) was introduced into a tube furnace. The temperature was increased to 200℃ at 5℃ / min and held for 0.5 h. Then the temperature was increased to 450℃ at 3℃ / min and sulfided for 5 h to obtain Ce / SiO2 coated with 12% MoS2 / Al2O3.

[0039] Using the above catalyst, vacuum residue hydrocracking was carried out in a slurry bed reactor under the following conditions: temperature 450℃, pressure 17MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 3 wt%, and shear rate 490 s⁻¹. -1 The homogenization time was 45 min, and a mixture of CO2 and H2 (volume ratio of 1:15) was passed through for 1.5 h every 24 h. The reaction results are shown in Table 1.

[0040] Example 4 The catalyst prepared in Example 3 is Ce / SiO2 coated with 15% MoS2 / Al2O3 (Ce:Si=1:50). S1. Dissolve 0.10 g of cerium nitrate in 25 parts of deionized water to form solution A. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts of deionized water, 20 parts of ethanol, and 20 parts of diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 80°C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40°C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550°C for 4 h to obtain Ce / SiO2 (Ce:Si molar ratio 1:50, specific surface area 460 m²). 2 / g, pore volume 1.10 cm³ 3 / g, pore size 13 nm).

[0041] S2. 1.0 g of Ce-SiO2 core was placed in the ALD reaction chamber. High-purity N2 was used as the carrier gas to sequentially introduce TMA and H2O into the reaction chamber, with nitrogen purging between them. The flow rate of the N2 carrier gas was 100 sccm, and the base pressure of the reaction chamber during deposition was 30 Pa. The pulse duration of both TMA and H2O introduction was 20 ms, and the purging time was 10 s. The substrate temperature was controlled at 280℃, and the number of cycles was 200. After deposition, the Ce / SiO2 core was activated by ultraviolet ozone treatment (UV / O3) at 180℃ for 3 h to obtain 22 nm Al2O3-encapsulated Ce / SiO2.

[0042] S3. The Ce / SiO2 coated with Al2O3 was impregnated twice in a 0.75 mol / L ammonium molybdate solution, sonicated for 30 min each time, dried at 60℃ for 6 h, and then H2 / H2S mixed gas (10:1, flow rate 50 mL / min) was introduced into a tube furnace. The temperature was increased to 200℃ at 5℃ / min and held for 0.5 h. Then the temperature was increased to 450℃ at 3℃ / min and sulfided for 5 h to obtain Ce / SiO2 coated with 15% MoS2 / Al2O3.

[0043] Using the above catalyst, vacuum residue hydrocracking was carried out in a slurry bed reactor under the following conditions: temperature 450℃, pressure 17MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 3 wt%, and shear rate 500 s⁻¹. -1 The homogenization time was 60 min, and a mixture of CO2 and H2 (volume ratio of 1:20) was passed through for 2 h every 24 h. The reaction results are shown in Table 1.

[0044] Example 5 The catalyst prepared in Example 5 is Zr / SiO2 (Zr:Si = 1:10) coated with 8% WS2 / Al2O3. S1. Dissolve 0.49 g of zirconium nitrate in 25 parts of deionized water to form solution A. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts of deionized water, 20 parts of ethanol, and 20 parts of diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 40°C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40°C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550°C for 4 h to obtain Zr / SiO2 (Ce:Si molar ratio 1:10, specific surface area 480 m²). 2 / g, pore volume 0.92 cm³ 3 / g, pore size 8 nm).

[0045] S2. 1.0 g of Zr-SiO2 core was placed in the ALD reaction chamber. High-purity N2 was used as the carrier gas to sequentially introduce TMA and H2O into the reaction chamber, with nitrogen purging between them. The flow rate of the N2 carrier gas was 100 sccm, and the base pressure of the reaction chamber during deposition was 30 Pa. The pulse duration of both TMA and H2O introduction was 20 ms, and the purging time was 10 s. The substrate temperature was controlled at 250℃, and the number of cycles was 80. After deposition, the Zr / SiO2 core was activated by ultraviolet ozone treatment (UV / O3) at 120℃ for 1 h to obtain 10 nm Al2O3-encapsulated Zr / SiO2.

[0046] S3. The Zr / SiO2 coated with Al2O3 is immersed in a 0.4 mol / L ammonium tungstate solution, sonicated for 30 min, dried at 60℃ for 6 h, and then H2 / H2S mixed gas (10:1, flow rate 50 mL / min) is introduced into a tube furnace. The temperature is increased to 200℃ at 2℃ / min and held for 0.5 h. Then the temperature is increased to 300℃ at 1℃ / min and sulfided for 3 h to obtain 8% WS2 / Al2O3 coated Zr / SiO2.

[0047] Using the above catalyst, hydrocracking of pyrolysis oil was carried out in a suspended bed reactor under the following conditions: temperature 410℃, pressure 14 MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 2 wt%, and shear rate 480 s⁻¹. -1 The homogenization time was 10 min, and a mixture of CO2 and H2 (volume ratio of 1:5) was passed through for 0.5 h every 24 h. The reaction results are shown in Table 2.

[0048] Example 6 The catalyst prepared in Example 6 is a Zr / SiO2 (Zr:Si = 1:20) coated with 10% WS2 / Al2O3. S1. Dissolve 0.24 g of zirconium nitrate in 25 parts of deionized water to form solution A. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts of deionized water, 20 parts of ethanol, and 20 parts of diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 60°C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40°C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550°C for 4 h to obtain Zr / SiO2 (Zr:Si molar ratio 1:20, specific surface area 490 m²). 2 / g, pore volume 0.95 cm³ 3 / g, pore size 6 nm).

[0049] S2. 1.0 g of Zr-SiO2 core was placed in the ALD reaction chamber. High-purity N2 was used as the carrier gas to sequentially introduce TMA and H2O into the reaction chamber, with nitrogen purging between them. The flow rate of the N2 carrier gas was 100 sccm, and the base pressure of the reaction chamber during deposition was 30 Pa. The pulse duration of both TMA and H2O introduction was 20 ms, and the purging time was 10 s. The substrate temperature was controlled at 200℃, and the number of cycles was 120. After deposition, the core was activated by ultraviolet ozone treatment (UV / O3) at 150℃ for 2 h to obtain 15 nm Al2O3-encapsulated Zr / SiO2.

[0050] S3. The Zr / SiO2 coated with Al2O3 was impregnated twice in a 0.5 mol / L ammonium tungstate solution, sonicated for 30 min each time, dried at 60℃ for 6 h, and then H2 / H2S mixed gas (10:1, flow rate 50 mL / min) was introduced into a tube furnace. The temperature was increased to 200℃ at 3℃ / min and held for 0.5 h. Then the temperature was increased to 350℃ at 2℃ / min and sulfided for 4 h to obtain Zr / SiO2 coated with 10%WS2 / Al2O3.

[0051] Using the above catalyst, hydrocracking of pyrolysis oil was carried out in a suspended bed reactor under the following conditions: temperature 380℃, pressure 12MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 1 wt%, and shear rate 480 s⁻¹. -1 The homogenization time was 30 min, and a mixture of CO2 and H2 (volume ratio of 1:10) was passed through for 1 h every 24 h. The reaction results are shown in Table 2.

[0052] Example 7 The catalyst prepared in Example 7 is a Zr / SiO2 (Zr:Si = 1:30) coated with 12% WS2 / Al2O3. S1. Dissolve 0.16 g of zirconium nitrate in 25 parts of deionized water to form solution A. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts of deionized water, 20 parts of ethanol, and 20 parts of diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 80°C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40°C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550°C for 4 h to obtain Zr / SiO2 (Zr:Si molar ratio 1:30, specific surface area 470 m²). 2 / g, pore volume 1.05 cm³ 3 / g, pore size 12 nm).

[0053] S2. 1.0 g of Zr-SiO2 core was placed in the ALD reaction chamber. High-purity N2 was used as the carrier gas to sequentially introduce TMA and H2O into the reaction chamber, with nitrogen purging between them. The flow rate of the N2 carrier gas was 100 sccm, and the base pressure of the reaction chamber during deposition was 30 Pa. The pulse duration of both TMA and H2O introduction was 20 ms, and the purging time was 10 s. The substrate temperature was controlled at 300℃, and the number of cycles was 240. After deposition, the Zr / SiO2 core was activated by ultraviolet ozone treatment (UV / O3) at 180℃ for 3 h to obtain 30 nm Al2O3-encapsulated Zr / SiO2.

[0054] S3. The Zr / SiO2 coated with Al2O3 was impregnated twice in a 0.7 mol / L ammonium tungstate solution, sonicated for 30 min each time, dried at 60℃ for 6 h, and then H2 / H2S mixed gas (10:1, flow rate 50 mL / min) was introduced into a tube furnace. The temperature was increased to 200℃ at 5℃ / min and held for 0.5 h. Then the temperature was increased to 450℃ at 3℃ / min and sulfided for 5 h to obtain Zr / SiO2 coated with 12% WS2 / Al2O3.

[0055] Using the above catalyst, hydrocracking of pyrolysis oil was carried out in a suspended bed reactor under the following conditions: temperature 450℃, pressure 17MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 3 wt%, and shear rate 490 s⁻¹. -1 The homogenization time was 45 min, and a mixture of CO2 and H2 (volume ratio of 1:15) was passed through for 1.5 h every 24 h. The reaction results are shown in Table 2.

[0056] Example 8 The catalyst prepared in Example 8 is Zr / SiO2 coated with 15% WS2 / Al2O3 (Zr:Si=1:50). S1. Dissolve 0.09 g of zirconium nitrate in 25 parts of deionized water to form solution A. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts of deionized water, 20 parts of ethanol, and 20 parts of diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 80°C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40°C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550°C for 4 h to obtain Zr / SiO2 (Zr:Si molar ratio 1:50, specific surface area 460 m²). 2 / g, pore volume 1.10 cm³ 3 / g, pore size 13 nm).

[0057] S2. 1.0 g of Zr-SiO2 core was placed in the ALD reaction chamber. High-purity N2 was used as the carrier gas to sequentially introduce TMA and H2O into the reaction chamber, with nitrogen purging between them. The flow rate of the N2 carrier gas was 100 sccm, and the base pressure of the reaction chamber during deposition was 30 Pa. The pulse duration of both TMA and H2O introduction was 20 ms, and the purging time was 10 s. The substrate temperature was controlled at 280℃, and the number of cycles was 200. After deposition, the core was activated by ultraviolet ozone treatment (UV / O3) at 180℃ for 3 h to obtain 22 nm Al2O3-encapsulated Zr / SiO2.

[0058] S3. The Zr / SiO2 coated with Al2O3 was impregnated twice in a 0.75 mol / L ammonium tungstate solution, sonicated for 30 min each time, dried at 60℃ for 6 h, and then H2 / H2S mixed gas (10:1, flow rate 50 mL / min) was introduced into a tube furnace. The temperature was increased to 200℃ at 5℃ / min and held for 0.5 h. Then the temperature was increased to 450℃ at 3℃ / min and sulfided for 5 h to obtain Zr / SiO2 coated with 15% WS2 / Al2O3.

[0059] Using the above catalyst, hydrocracking of pyrolysis oil was carried out in a suspended bed reactor under the following conditions: temperature 450℃, pressure 17MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 3 wt%, and shear rate 500 s⁻¹. -1 The homogenization time was 60 min, and a mixture of CO2 and H2 (volume ratio of 1:20) was passed through for 2 h every 24 h. The reaction results are shown in Table 2.

[0060] Comparative Example 1 The catalyst prepared in Comparative Example 1 was Ce / SiO2 coated with 10% MoS2 / Al2O3 (Ce:Si=1:20) (without UV ozone treatment). S1. Dissolve 0.25 g of cerium nitrate in 25 parts of deionized water to form solution A. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts of deionized water, 20 parts of ethanol, and 20 parts of diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 60°C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40°C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550°C for 4 h to obtain Ce / SiO2 (Ce:Si molar ratio 1:20, specific surface area 800 m²). 2 / g, pore size 6 nm).

[0061] S2. Place 1.0 g of Ce-SiO2 core in the ALD reaction chamber. Use high-purity N2 as the carrier gas to sequentially introduce TMA and H2O into the reaction chamber, purging with nitrogen between them. The N2 carrier gas flow rate is 100 sccm, and the base pressure of the reaction chamber during deposition is 30 Pa. The pulse duration for introducing TMA and H2O is 20 ms, and the purging time is 10 s. The substrate temperature is controlled at 200℃, and the number of cycles is 120 to obtain 15 nm Al2O3-encapsulated Ce / SiO2.

[0062] S3. The Ce / SiO2 coated with Al2O3 was impregnated in a 0.5 mol / L ammonium molybdate solution twice, and ultrasonically treated for 30 min each time. After drying at 60℃ for 6 h, a H2 / H2S mixed gas (10:1, flow rate 50 mL / min) was introduced into a tube furnace, and the temperature was increased to 200℃ at 3℃ / min and held for 0.5 h. Then, the temperature was increased to 350℃ at 2℃ / min and sulfurized for 4 h to obtain Ce / SiO2 coated with 10% MoS2 / Al2O3.

[0063] Using the above catalyst, vacuum residue hydrocracking reaction was carried out in a suspended bed reactor under the following conditions: temperature 380℃, pressure 12MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 1 wt%, shear rate 8000 rpm, homogenization time 30 min, and a mixture of CO2 and H2 (volume ratio 1:10) was passed through for 1 h every 24 h. The reaction results are shown in Table 1.

[0064] Comparative Example 2 The catalyst prepared in Comparative Example 2 was Ce / SiO2 (Ce:Si = 1:20). S1. Dissolve 0.25 g of cerium nitrate in 25 parts of deionized water to form solution A. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts of deionized water, 20 parts of ethanol, and 20 parts of diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 60°C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40°C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550°C for 4 h to obtain Ce / SiO2 (Ce:Si molar ratio 1:20, specific surface area 800 m²). 2 / g, pore size 6 nm).

[0065] Using the above catalyst, vacuum residue hydrocracking reaction was carried out in a suspended bed reactor under the following conditions: temperature 380℃, pressure 12MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 1 wt%, shear rate 8000 rpm, homogenization time 30 min, and a mixture of CO2 and H2 (volume ratio 1:10) was passed through for 1 h every 24 h. The reaction results are shown in Table 1.

[0066] Comparative Example 3 The catalyst prepared in Comparative Example 3 was SiO2 coated with 10% MoS2 / Al2O3. S1. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts deionized water, 20 parts ethanol, and 20 parts diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 60 °C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40 °C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550 °C for 4 h to obtain SiO2 (specific surface area 800 m²). 2 / g, pore size 6 nm).

[0067] S2. Place 1.0 g of SiO2 core in the ALD reaction chamber. Use high-purity N2 as the carrier gas to sequentially introduce TMA and H2O into the reaction chamber, purging with nitrogen between them. The N2 carrier gas flow rate is 100 sccm, and the base pressure of the reaction chamber during deposition is 30 Pa. The pulse duration for introducing TMA and H2O is 20 ms, and the purging time is 10 s. The substrate temperature is controlled at 200℃, and the number of cycles is 120 to obtain 15 nm Al2O3-encapsulated SiO2.

[0068] S3. The Ce / SiO2 coated with Al2O3 was impregnated in a 0.5 mol / L ammonium molybdate solution twice, each time ultrasonically treated for 30 min, dried at 60℃ for 6 h, and H2 / H2S mixed gas (10:1, flow rate 50 mL / min) was introduced into a tube furnace. The temperature was increased to 200℃ at 3℃ / min and held for 0.5 h, and then increased to 350℃ at 2℃ / min for 4 h to obtain SiO2 coated with 10% MoS2 / Al2O3.

[0069] Using the above catalyst, vacuum residue hydrocracking reaction was carried out in a suspended bed reactor under the following conditions: temperature 380℃, pressure 12MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 1 wt%, shear rate 8000 rpm, homogenization time 30 min, and a mixture of CO2 and H2 (volume ratio 1:10) was passed through for 1 h every 24 h. The reaction results are shown in Table 1.

[0070] Comparative Example 4 The catalyst prepared in Comparative Example 4 was a Zr / SiO2 (Zr:Si = 1:20) coated with 10% WS2 / Al2O3 (without UV ozone treatment). S1. Dissolve 0.24 g of zirconium nitrate in 25 parts of deionized water to form solution A. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts of deionized water, 20 parts of ethanol, and 20 parts of diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 60°C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40°C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550°C for 4 h to obtain Zr / SiO2 (Zr:Si molar ratio 1:20, specific surface area 800 m²). 2 / g, pore size 6 nm).

[0071] S2. Place 1.0 g of Zr-SiO2 core in the ALD reaction chamber. Use high-purity N2 as the carrier gas to sequentially introduce TMA and H2O into the reaction chamber, purging with nitrogen between them. The N2 carrier gas flow rate is 100 sccm, and the base pressure of the reaction chamber during deposition is 30 Pa. The pulse duration for introducing TMA and H2O is 20 ms, and the purging time is 10 s. The substrate temperature is controlled at 200℃, and the number of cycles is 120 to obtain 15 nm Al2O3-encapsulated Zr / SiO2.

[0072] S3. The Zr / SiO2 coated with Al2O3 was impregnated in a 0.5 mol / L ammonium tungstate solution twice, each time ultrasonically treated for 30 min, dried at 60℃ for 6 h, and then H2 / H2S mixed gas (10:1, flow rate 50 mL / min) was introduced into a tube furnace. The temperature was increased to 200℃ at 3℃ / min and held for 0.5 h. Then the temperature was increased to 350℃ at 2℃ / min and sulfided for 4 h to obtain Zr / SiO2 coated with 10%WS2 / Al2O3.

[0073] Using the above catalyst, hydrocracking of cracked oil was carried out in a suspended bed reactor under the following conditions: temperature 380℃, pressure 12MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 1 wt%, shear rate 8000 rpm, homogenization time 30 min, and a mixture of CO2 and H2 (volume ratio 1:10) was passed through for 1 h every 24 h. The reaction results are shown in Table 2.

[0074] Comparative Example 5 The catalyst prepared in Comparative Example 5 is a Zr / SiO2 (Zr:Si = 1:20) catalyst. S1. Dissolve 0.24 g of zirconium nitrate in 25 parts of deionized water to form solution A. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts of deionized water, 20 parts of ethanol, and 20 parts of diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 60°C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40°C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550°C for 4 h to obtain Zr / SiO2 (Zr:Si molar ratio 1:20, specific surface area 800 m²). 2 / g, pore size 6 nm).

[0075] Using the above catalyst, hydrocracking of cracked oil was carried out in a suspended bed reactor under the following conditions: temperature 380℃, pressure 12MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 1 wt%, shear rate 8000 rpm, homogenization time 30 min, and a mixture of CO2 and H2 (volume ratio 1:10) was passed through for 1 h every 24 h. The reaction results are shown in Table 2.

[0076] Comparative Example 6 The catalyst prepared in Comparative Example 6 was SiO2 encapsulated with 10% WS2 / Al2O3. S1. Dissolve 0.5 g of CTAB in a mixed solution of 60 parts deionized water, 20 parts ethanol, and 20 parts diethyl ether. While stirring, add 0.8 mL of ammonia water dropwise, then add solution A. Add 2.5 mL of TEOS and stir at 60 °C for 4 h. Filter and wash the resulting powder, then transfer it to a supercritical CO2 drying apparatus and dry it at 40 °C and 10 MPa for 12 h to obtain a white powder. Calcine the powder at 550 °C for 4 h to obtain SiO2 (specific surface area 800 m²). 2 / g, pore size 6 nm).

[0077] S2. Place 1.0 g of SiO2 core in the ALD reaction chamber. Use high-purity N2 as the carrier gas to sequentially introduce TMA and H2O into the reaction chamber, purging with nitrogen between them. The N2 carrier gas flow rate is 100 sccm, and the base pressure of the reaction chamber during deposition is 30 Pa. The pulse duration for introducing TMA and H2O is 20 ms, and the purging time is 10 s. The substrate temperature is controlled at 200℃, and the number of cycles is 120 to obtain 15 nm Al2O3-encapsulated SiO2.

[0078] S3. The SiO2 coated with Al2O3 was impregnated in a 0.5 mol / L ammonium tungstate solution twice, each time ultrasonically treated for 30 min, dried at 60℃ for 6 h, and H2 / H2S mixed gas (10:1, flow rate 50 mL / min) was introduced into a tube furnace. The temperature was increased to 200℃ at 3℃ / min and held for 0.5 h, and then increased to 350℃ at 2℃ / min for 4 h to obtain SiO2 coated with 10% WS2 / Al2O3.

[0079] Using the above catalyst, hydrocracking of cracked oil was carried out in a suspended bed reactor under the following conditions: temperature 380℃, pressure 12MPa, hydrogen-to-oil ratio 1000:1, catalyst addition 1 wt%, shear rate 8000 rpm, homogenization time 30 min, and a mixture of CO2 and H2 (volume ratio 1:10) was passed through for 1 h every 24 h. The reaction results are shown in Table 2.

[0080] Table 1 Evaluation results of Examples 1-4 and Comparative Examples 1-3

[0081] Table 2 Evaluation results of Examples 5-8 and Comparative Examples 4-6

[0082] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A multifunctional core-shell structure catalyst for heavy oil hydrocracking, characterized in that, The catalyst includes: Core: Composed of mesoporous silicon dioxide doped with metal, wherein the doping metal is selected from at least one of Zr and Ce, and the doping amount is 5% to 15% of the total mass of the core; The outer shell is composed of a transition metal sulfide supported on an alumina carrier, wherein the transition metal sulfide is at least one of MoS2 or WS2; The core of the core-shell structure has a mesopore size of 5-15 nm and an alumina layer thickness of 10-30 nm. The interface between the core and the alumina carrier is treated with ultraviolet ozone to enhance the bonding strength.

2. The core-shell structured catalyst according to claim 1, characterized in that, The specific surface area of ​​the mesoporous silica core is 400-500 m². 2 / g, total pore volume is 0.5~1.2 cm³ 3 / g.

3. The core-shell structured catalyst according to claim 1 or 2, characterized in that, The loading of transition metal sulfides in the outer shell is 5% to 15% of the total mass of the catalyst; Preferably, the loading of transition metal sulfides in the outer shell is 8% to 12% of the total mass of the catalyst.

4. A method for preparing a core-shell structured catalyst according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Prepare a certain amount of cerium source or zirconium source solution, dissolve hexadecyltrimethylammonium nitrate (CTAB) in a certain proportion of a mixed solution of deionized water, ethanol, and diethyl ether, then add a certain amount of ammonia water, add the cerium source or zirconium source solution; then add the silicon source, stir, filter, wash, dry with supercritical CO2, and calcine to obtain Ce / Zr:SiO2. S2. Place the core in the atomic layer deposition (ALD) reaction chamber, use high-purity N2 as the carrier gas, and sequentially introduce trimethylaluminum (TMA) and H2O into the reaction chamber. Nitrogen gas is used to purge between them. By controlling the temperature of the reaction chamber and the number of cycles, an Al2O3-encapsulated core can be obtained. S3. Prepare a solution of ammonium molybdate / ammonium tungstate of a certain concentration, impregnate it on the surface of Al2O3, sonicate it, dry it, and reduce and sulfide it in a tube furnace by introducing a certain proportion of H2 / H2S mixed gas to obtain a core-shell catalyst supported on MoS2 and / or WS2.

5. The preparation method according to claim 4, characterized in that, In step S1, the silicon source is tetraethyl orthosilicate (TEOS), the zirconium source is zirconium nitrate, and the cerium source is cerium nitrate. The molar ratio of zirconium / cerium to silicon is 1:(10~50); Hexadecyltrimethylammonium nitrate (CTAB) was used as a template agent for hydrolysis and condensation at 40-80°C. The conditions for supercritical CO2 drying were: drying at 40℃ and 10 MPa for 12 h. The calcination conditions were: 550℃ for 4 hours.

6. The preparation method according to claim 4, characterized in that, In step S2, the carrier gas is high-purity N2 with a flow rate of 100 sccm and a base pressure of 30 Pa in the reaction chamber. The pulse duration for both TMA and H2O was 20 ms, and the purge time was 10 s. The substrate temperature is 200-300℃, and the number of cycles is 80-240.

7. The preparation method according to any one of claims 4-6, characterized in that, In step S3, the ultraviolet ozone treatment is carried out at 120–180°C for 1–3 hours.

8. The preparation method according to any one of claims 4-7, characterized in that, In step S4, The molybdenum or tungsten source is ammonium molybdate or ammonium tungstate, with a solution concentration of 0.3–0.7 M; Immerse 1-2 times, with each ultrasonic treatment lasting 20-60 minutes; The vulcanization process adopts a segmented heating program: first, the temperature is increased to 200℃ at 2~5℃ / min and held for 0.5 h, and then the temperature is increased to the target vulcanization temperature at 1~3℃ / min.

9. A hydrocracking process, characterized in that, The core-shell structure catalyst according to any one of claims 1 to 3 is used, and the reactant is at least one of vacuum residue, shale oil, or cracked oil, and the reaction conditions are as follows: Includes: reaction temperature: 350~450℃; reaction pressure: 8~20 MPa; hydrogen-to-oil volume ratio: (500~1500):1; catalyst addition amount: 0.1%~5% of raw material mass; The process is carried out in a suspended bed reactor. After the catalyst and feedstock oil are premixed, they are homogenized by a high-speed shear machine at a shear rate of 200-500 s⁻¹. -1 The homogenization time is 10~60 min.

10. The hydrocracking process according to claim 9, characterized in that, During the reaction, a mixture of CO2 and H2 gas with a volume ratio of 1:(5-20) is periodically introduced to remove carbon buildup on the catalyst surface in situ. The frequency of introducing the CO2 and H2 mixture is once every 24 hours, and each time it lasts for 0.5 to 2 hours; The effective removal of carbon deposits is attributed to the stability of the core-shell structure and the highly dispersed MoS2 / WS2 active sites of the catalyst, which enable CO2 to effectively contact and vaporize the carbon deposits on the surface.

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