A high-silicon multi-stage hole crude benzene hydrogenation catalyst resistant to organosilicon poisoning and a preparation method thereof

Abstract

The present application relates to the field of deep hydrodesulfurization of crude benzene, and discloses a modified supported catalyst for deep hydrodesulfurization of crude benzene, which is composed of a carrier, a main active metal oxide, an alkali metal oxide and an alkali earth metal oxide additive, and a modified noble metal oxide; the carrier exists in the form of particles, and the carrier is composed of gamma-Al2O3, has a specific surface area of 150-250 m2 / g, a pore volume of 0.4-0.6 cm3 / g, and a particle surface composed of an outer particle surface and an inner particle pore surface; the main active metal oxide is CoO and MoO3, wherein CoO accounts for 3-6 wt% of the total amount of the catalyst, and MoO3 accounts for 8-14 wt% of the total amount of the catalyst; the main active metal oxide is loaded through an impregnation method; and the alkali metal oxide and the alkali earth metal oxide additive are one or a combination of K2O and MgO, and the additive accounts for 0.5-2.0 wt% of the total amount of the catalyst.

Description

Technical Field

[0001] This invention relates to the field of catalytic technology for the hydrorefining of crude benzene from coking plants, specifically to a multi-level porous composite support hydrogenation catalyst that is resistant to impurities, resistant to organosilicon poisoning, and has high silicon capacity. It is particularly suitable for the hydrodesulfurization and olefin saturation process of inferior crude benzene feedstock with high impurity content and high content of organosilicon poisons. Background Technology

[0002] Currently, due to the mixed sources of raw materials and adjustments to the crude benzene feedstock production process, the crude benzene hydrogenation refining industry is generally facing a trend of deteriorating raw material quality. The content of impurities such as organosilicon compounds (methylsiloxanes, ethylsiloxanes, phenylsiloxanes, silicone oils), gums, and heavy unsaturated substances in the crude benzene feedstock has increased significantly compared to before. Under hydrogenation reaction conditions, organosilicon compounds will undergo C-Si and O-Si bond breakage, generating amorphous silica deposits, which preferentially block the micropores and pore structures of the catalyst, causing a rapid decrease in the catalyst's specific surface area, pore channel closure, and coverage of active sites. Ultimately, this leads to catalyst deactivation within a short period, frequent catalyst replacement, and a significant reduction in operating rate.

[0003] Currently, the mainstream industrial crude benzene hydrogenation catalysts still use traditional γ-alumina as the carrier, which generally suffers from defects such as low specific surface area, small pore volume, and simple pore structure. They also have low silicon capacity and weak resistance to poisoning, making them unsuitable for processing high-impurity and low-quality crude benzene raw materials.

[0004] Limited by the properties of γ-alumina carriers, simply increasing the specific surface area and pore volume not only has insufficient room for improvement, but also fails to deeply improve the carrier structure and chemical properties, resulting in limited improvement in silicon-containing effect and anti-poisoning ability. Meanwhile, new materials such as mesoporous molecular sieves and carbon-based carriers have problems such as high cost, difficult molding, poor mechanical strength, and difficulty in industrial scale-up, and cannot be directly applied to industrial fixed-bed crude benzene hydrogenation units.

[0005] Therefore, developing a crude benzene hydrogenation catalyst that combines a multi-level pore structure, high specific surface area, large pore volume, directional silica compatibility, and resistance to organosilicon poisoning has become a core technological requirement for solving the processing of inferior crude benzene and extending catalyst life. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a crude benzene hydrogenation catalyst that is resistant to organosilicon poisoning, has high silica capacity, and exhibits multi-level porous structure, as well as a method for its preparation, addressing the issues of easy poisoning, pore blockage, and short lifespan of existing crude benzene hydrogenation catalysts under conditions of high organosilicon and high impurity raw materials.

[0007] The technical solution adopted in this invention is: a high-silica, multi-level porous crude benzene hydrogenation catalyst resistant to organosilicon poisoning, comprising a multi-level gradient pore structure of a composite support, a main active metal, and molybdenum oxide, with a catalyst specific surface area of ​​280-380 m². 2 / g, pore volume 0.8-1.3cm 3 / g; The composite support is a composite support formed by γ-Al2O3, SiO2, ZrO3, and MgO. Based on the total weight of the catalyst, the SiO2 content is 7.0-8.0 wt%, the ZrO2 content is 10.0-12.0 wt%, and the MgO content is 1.0-2.0 wt%. The main active metals are CoO and MoO3, with CoO accounting for 3.0-6.0 wt% and MoO3 accounting for 8.0-14.0 wt% of the total catalyst weight.

[0008] The multi-level gradient pore structure is a multi-level gradient pore composed of macropores, mesopores and micropores, wherein the macropore diameter is greater than 50nm and less than or equal to 200nm, the mesopore diameter is greater than 8nm and less than or equal to 50nm, and the micropore diameter is less than or equal to 8nm.

[0009] A method for preparing a high-capacity, multi-level porous crude benzene hydrogenation catalyst resistant to organosilicon poisoning includes the following steps: Step 1, Raw material selection: Aluminum nitrate is used as the aluminum source, tetraethyl orthosilicate (TEOS) is used as the silicon source, zirconium nitrate is used as the zirconium source, magnesium nitrate is used as the magnesium source, P123 is used as the mesoporous template agent, and soluble starch is used as the macroporous template agent. Step 2, Preparation of precursor solution: According to the catalyst composition, dissolve aluminum nitrate, tetraethyl orthosilicate (TEOS), zirconium nitrate, and magnesium nitrate in a 23-27 wt% ethanol aqueous solution; the solid components (aluminum nitrate, TEOS, zirconium nitrate, and magnesium nitrate) account for 18-21 wt% of the mass in the ethanol aqueous solution; Step 3: Add template agent: Add P123 to the solution and dissolve it completely, then add soluble starch and stir to disperse evenly; wherein P123 accounts for 9-11% of the solid phase mass, and starch accounts for 7.5-8.5% of the total solid phase mass; Step 4, co-precipitation: At 20-30℃, slowly add dilute ammonia to the solution to adjust the pH of the system to 9.0-9.5, and continue stirring to form a uniform composite hydroxide gel; Step 5, hydrothermal aging: Transfer to a hydrothermal autoclave and keep at 105-115℃ for 8-10 hours to stabilize the skeleton and pre-form the multi-level channels; Step 6, Precursor Post-processing: Static aging, allow natural static aging for 16-24 hours to allow the components to fully mix and blend; Wash and filter, wash with deionized water until neutral to remove free salt ions; Dry at 100-110℃ for 10-12 hours, sieve through 100-120 mesh to obtain powder; Step 7, Extrusion Molding: Based on the above powder mass, add guar gum powder (2.5-4 wt% of powder mass); add boehmite (12-15 wt% of powder mass); add 65-68 wt% concentrated nitric acid (1.5-3 wt% of powder mass); add deionized water (35-45 wt% of powder mass); mix evenly, extrude into strips; dry at 100-110℃ for 10-12 h; calcine at 500-520℃ for 5-8 h to obtain the composite carrier; Step 8: Loading of active components: According to the catalyst composition, prepare a mixed solution of cobalt nitrate and ammonium heptamolybdate. Impregnate the composite support in the mixed solution of cobalt nitrate and ammonium heptamolybdate with an equal volume. After impregnation, dry at 100-110℃ for 10-12h and calcine at 500-520℃ for 5-8h to obtain the catalyst. In the mixed solution of cobalt nitrate and ammonium heptamolybdate, the concentration of ammonium heptamolybdate is 10-17wt% and the concentration of cobalt nitrate is 5%-12%.

[0010] Application of a high-capacity, multi-hierarchical porous catalyst for the hydrogenation of crude benzene, resistant to organosilicon poisoning, used in the hydrogenation reaction of crude benzene at a reaction temperature of 270-340℃, a pressure of 1.5-3.5 MPa, and a liquid hourly space velocity of 1.5-2.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 600-900. Before using the catalyst, a H2S-N2 mixture with a volume fraction of 9-12% H2S is used to pre-sulfurize the catalyst at 300-320℃ for 4-6 hours.

[0011] The beneficial effects of this invention are as follows: The catalyst of this invention is based on γ-Al₂O₃, and introduces SiO₂ components into the support to improve the thermal stability and texture properties of the support, thereby increasing the pore volume and specific surface area. The catalyst of this invention introduces ZrO₂ components into the support to reduce the hydroxyl density on the support surface, inhibit strong Brønsted acid, slow down the hydrolysis rate of organosilicon, and delay the generation and deposition of SiO₂. The catalyst of this invention introduces alkaline earth metal oxide components into the support to provide dispersed alkaline sites, allowing the weakly acidic silanol groups and oligomeric silica species generated by organosilicon hydrolysis to preferentially adsorb at these dispersed sites based on acid-base affinity, avoiding the active centers of hydrodesulfurization and the main channels, preventing large-area continuous crusting and pore blockage, and delaying overall deactivation. The catalyst of this invention constructs a gradient multi-level pore structure, increasing the pore volume and specific surface area, enhancing the SiO₂ deposition capacity, and extending the catalyst lifetime. Detailed Implementation

[0012] Example 1: A high-capacity, multi-hierarchical porous coarse benzene hydrogenation catalyst resistant to organosilicon poisoning, and its preparation method and utilization. A high-silica, multi-level porous crude benzene hydrogenation catalyst resistant to organosilicon poisoning, comprising a multi-level gradient pore structure of a composite support, a main active metal, and molybdenum oxide; the catalyst has a specific surface area of ​​368 m². 2 / g, pore volume 1.26cm 3 / g represents a multi-level gradient pore structure; The composite support is a composite support formed by γ-A2O3, SiO2, ZrO2, and MgO. Based on the total weight of the catalyst, the SiO2 content is 7.5 wt%, the ZrO2 content is 12.0 wt%, and the MgO content is 1.5 wt%. The main active metals are CoO and MoO3, with CoO accounting for 6.0 wt% and MoO3 accounting for 14.0 wt% of the total catalyst weight.

[0013] The multi-level gradient pore structure is a multi-level gradient pore composed of macropores, mesopores and micropores, wherein the macropore diameter is greater than 50nm and less than or equal to 200nm, the mesopore diameter is greater than 8nm and less than or equal to 50nm, and the micropore diameter is less than or equal to 8nm.

[0014] A method for preparing a high-capacity, multi-level porous coarse benzene hydrogenation catalyst resistant to organosilicon poisoning includes the following steps: Step 1, Raw material selection: Aluminum nitrate is used as the aluminum source, tetraethyl orthosilicate (TEOS) is used as the silicon source, zirconium nitrate is used as the zirconium source, magnesium nitrate is used as the magnesium source, P123 is used as the mesoporous template agent, and soluble starch is used as the macroporous template agent. Step 2, Preparation of precursor solution: According to the catalyst composition, dissolve aluminum nitrate, tetraethyl orthosilicate (TEOS), zirconium nitrate, and magnesium nitrate in a 23 wt% ethanol aqueous solution; the solid components (aluminum nitrate, TEOS, zirconium nitrate, and magnesium nitrate) account for 20 wt% of the mass in the ethanol aqueous solution; Step 3: Add template agent: Add P123 to the solution and dissolve it completely, then add soluble starch and stir to disperse evenly; wherein P123 accounts for 11% of the solid phase mass and starch accounts for 8.5% of the total solid phase mass; Step 4, co-precipitation: At 28℃, slowly add dilute ammonia to the solution to adjust the pH of the system to 9.0, and continue stirring to form a uniform composite hydroxide gel; Step 5, hydrothermal aging: Transfer to a hydrothermal autoclave, keep at 110℃ for 10 hours to stabilize the skeleton and pre-form the multi-level channels; Step 6, Precursor Post-processing: Static aging, allow natural static aging for 24 hours to allow the components to fully mix and blend; Wash and filter, wash with deionized water until neutral to remove free salt ions; Dry at 100℃ for 11 hours, sieve through 100 mesh to obtain powder; Step 7, Extrusion Molding: Based on the above powder mass, add guar gum powder (2.5 wt% of powder mass), boehmite (13 wt% of powder mass), concentrated nitric acid (68 wt% of powder mass), and deionized water (45 wt% of powder mass); mix evenly, extrude into strips; dry at 110℃ for 12 hours; calcine at 500℃ for 7 hours to obtain the composite carrier; Step 8: Loading of active components: According to the catalyst composition, prepare a mixed solution of cobalt nitrate and ammonium heptamolybdate. Impregnate the composite support in the mixed solution of cobalt nitrate and ammonium heptamolybdate with equal volume. After impregnation, dry at 110°C for 12 hours and calcine at 500°C for 7 hours to obtain the catalyst. In the mixed solution of cobalt nitrate and ammonium heptamolybdate, the concentration of ammonium heptamolybdate is 16 wt% and the concentration of cobalt nitrate is 7 wt%.

[0015] An application of a high-capacity, multi-hierarchical porous catalyst resistant to organosilicon poisoning in the hydrogenation of crude benzene is disclosed. This catalyst is used for the hydrogenation reaction of crude benzene (Si content 12 ppm, S content 750 ppm, bromine index 1100 mgBr / 100g, aromatics mass fraction 64%). The feedstock passes through a C9+ removal tower to remove heavy components, gums, and asphaltenes, and undergoes a pre-hydrogenation process before entering the crude benzene hydrogenation reaction unit. The reaction temperature is 290℃, the pressure is 2 MPa, and the liquid hourly space velocity is 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 700. Before using the catalyst, a hydrogen sulfide-nitrogen mixture with a hydrogen sulfide volume fraction of 9% is used to pre-sulfurize the catalyst at 320℃ for 5 hours.

[0016] Evaluation results: After 180 days of reaction evaluation, the initial desulfurization rate was 99.9% after the reaction stabilized. The initial product bromine index was 10 mgBr / 100g. After 180 days of reaction, the catalyst specific surface area was 358 m². 2 / g, pore volume 0.95cm 3 / g, activity decrease rate 1.2%.

[0017] Example 2: A high-capacity, multi-hierarchical porous coarse benzene hydrogenation catalyst resistant to organosilicon poisoning, and its preparation method and utilization. A high-capacity silica multi-level porous crude benzene hydrogenation catalyst resistant to organosilicon poisoning, comprising a multi-level gradient pore structure consisting of a composite support, a main active metal, and molybdenum oxide; The composite support is a composite support formed by γ-A2O3, SiO2, ZrO2, and MgO. Based on the total weight of the catalyst, the SiO2 content is 7 wt%, the ZrO2 content is 10.0 wt%, and the MgO content is 1.0 wt%. The main active metals are CoO and MoO3, with CoO accounting for 3.0 wt% and MoO3 accounting for 12.0 wt% of the total catalyst weight.

[0018] A method for preparing a high-capacity, multi-level porous coarse benzene hydrogenation catalyst resistant to organosilicon poisoning includes the following steps: Step 1, Raw material selection: Aluminum nitrate is used as the aluminum source, tetraethyl orthosilicate (TEOS) is used as the silicon source, zirconium nitrate is used as the zirconium source, magnesium nitrate is used as the magnesium source, P123 is used as the mesoporous template agent, and soluble starch is used as the macroporous template agent. Step 2, Preparation of precursor solution: According to the catalyst composition, dissolve aluminum nitrate, tetraethyl orthosilicate (TEOS), zirconium nitrate, and magnesium nitrate in a 25 wt% ethanol aqueous solution; the solid components (aluminum nitrate, TEOS, zirconium nitrate, and magnesium nitrate) account for 19 wt% of the mass of the ethanol aqueous solution; Step 3: Add template agent: Add P123 to the solution and dissolve it completely, then add soluble starch and stir to disperse evenly; wherein P123 accounts for 9% of the solid phase mass and starch accounts for 8% of the total solid phase mass; Step 4, co-precipitation: At 30℃, slowly add dilute ammonia to the solution to adjust the pH of the system to 9.2, and continue stirring to form a uniform composite hydroxide gel; Step 5, hydrothermal aging: Transfer to a hydrothermal autoclave, keep at 105℃ for 10 hours to stabilize the skeleton and pre-form the multi-level channels; Step 6, Precursor Post-processing: Static aging, allow natural static aging for 20 hours to allow the components to fully mix and blend; Wash and filter, wash with deionized water until neutral to remove free salt ions; Dry at 105℃ for 11 hours, sieve through 120 mesh to obtain powder; Step 7, Extrusion Molding: Based on the above powder mass, add guar gum powder (3.0 wt% of powder mass), add boehmite (12 wt% of powder mass), add 65 wt% concentrated nitric acid (2.0 wt% of powder mass), add deionized water (40 wt% of powder mass), mix evenly, and extrude into strips; dry at 105℃ for 12 h; calcine at 500℃ for 7 h to obtain the composite carrier; Step 8: Loading of active components: According to the catalyst composition, prepare a mixed solution of cobalt nitrate and ammonium heptamolybdate. Impregnate the composite support in the mixed solution of cobalt nitrate and ammonium heptamolybdate with an equal volume. After impregnation, dry at 110°C for 12 hours and calcine at 510°C for 7 hours to obtain the catalyst. In the mixed solution of cobalt nitrate and ammonium heptamolybdate, the concentration of ammonium heptamolybdate is 15 wt% and the concentration of cobalt nitrate is 7 wt%.

[0019] An application of a high-capacity, multi-hierarchical porous catalyst for the hydrogenation of crude benzene, resistant to organosilicon poisoning, was conducted on crude benzene (Si content 12 ppm, S content 750 ppm, bromine index 1100 mgBr / 100g, aromatic mass fraction 64%). The reaction temperature was 300℃, the pressure was 3 MPa, and the liquid hourly space velocity was 2 h⁻¹. -1The hydrogen-to-oil volume ratio is 800. Before using the catalyst, a hydrogen sulfide-nitrogen mixture with a hydrogen sulfide volume fraction of 9% is used to pre-sulfurize the catalyst at 320℃ for 5 hours.

[0020] Evaluation results: After 180 days of reaction evaluation, the initial desulfurization rate was 99.8% after the reaction stabilized. The initial product bromine index was 12 mgBr / 100g. After 180 days of reaction, the catalyst specific surface area was 351 m². 2 / g, pore volume is 0.88cm 3 / g, activity decrease rate 1.5%.

[0021] Example 3: A high-capacity, multi-hierarchical porous coarse benzene hydrogenation catalyst resistant to organosilicon poisoning, its preparation method, and its utilization. A high-capacity silica multi-level porous crude benzene hydrogenation catalyst resistant to organosilicon poisoning, comprising a multi-level gradient pore structure consisting of a composite support, a main active metal, and molybdenum oxide; The composite support is a composite support formed by γ-A2O3, SiO2, ZrO2, and MgO. Based on the total weight of the catalyst, the SiO2 content is 8 wt%, the ZrO2 content is 11.0 wt%, and the MgO content is 2.0 wt%. The main active metals are CoO and MoO3, with CoO accounting for 4.0 wt% and MoO3 accounting for 13.0 wt% of the total catalyst weight.

[0022] A method for preparing a high-capacity, multi-level porous coarse benzene hydrogenation catalyst resistant to organosilicon poisoning includes the following steps: Step 1, Raw material selection: Aluminum nitrate is used as the aluminum source, tetraethyl orthosilicate (TEOS) is used as the silicon source, zirconium nitrate is used as the zirconium source, magnesium nitrate is used as the magnesium source, P123 is used as the mesoporous template agent, and soluble starch is used as the macroporous template agent. Step 2, Preparation of precursor solution: According to the catalyst composition, dissolve aluminum nitrate, tetraethyl orthosilicate (TEOS), zirconium nitrate, and magnesium nitrate in a 26 wt% ethanol aqueous solution; the solid components (aluminum nitrate, TEOS, zirconium nitrate, and magnesium nitrate) account for 21 wt% of the mass of the ethanol aqueous solution; Step 3: Add template agent: Add P123 to the solution and dissolve it completely, then add soluble starch and stir to disperse evenly; wherein P123 accounts for 10% of the solid phase mass and starch accounts for 7.5% of the total solid phase mass; Step 4, co-precipitation: At 25℃, slowly add dilute ammonia to the solution to adjust the pH of the system to 9.5, and continue stirring to form a uniform composite hydroxide gel; Step 5, hydrothermal aging: Transfer to a hydrothermal autoclave, keep at 110℃ for 8 hours to stabilize the skeleton and pre-form multi-level channels; Step 6, Precursor Post-processing: Static aging, allow natural static aging for 22 hours to allow the components to fully mix and blend; Wash and filter, wash with deionized water until neutral to remove free salt ions; Dry at 110℃ for 10 hours, sieve through 110 mesh to obtain powder; Step 7, Extrusion Molding: Based on the above powder mass, add guar gum powder (4.0 wt% of powder mass), boehmite (14 wt% of powder mass), concentrated nitric acid (66 wt% of powder mass), and deionized water (35 wt% of powder mass); mix evenly, extrude into strips; dry at 105℃ for 12 hours; calcine at 520℃ for 6 hours to obtain the composite carrier; Step 8: Loading of active components: According to the catalyst composition, prepare a mixed solution of cobalt nitrate and ammonium heptamolybdate. Impregnate the composite support in the mixed solution of cobalt nitrate and ammonium heptamolybdate with an equal volume. After impregnation, dry at 105℃ for 12h and calcine at 520℃ for 8h to obtain the catalyst. In the mixed solution of cobalt nitrate and ammonium heptamolybdate, the concentration of ammonium heptamolybdate is 18wt% and the concentration of cobalt nitrate is 10wt%.

[0023] An application of a high-capacity, multi-hierarchical porous catalyst resistant to organosilicon poisoning in the hydrogenation of crude benzene is disclosed. This catalyst is used for the hydrogenation reaction of crude benzene (Si content 12 ppm, S content 750 ppm, bromine index 1100 mgBr / 100g, aromatics mass fraction 64%). The feedstock passes through a C9+ removal tower to remove heavy components, gums, and asphaltenes, and undergoes a pre-hydrogenation process before entering the crude benzene hydrogenation reaction unit. The reaction temperature is 280℃, the pressure is 2.5 MPa, and the liquid hourly space velocity is 2.5 h⁻¹. -1 The hydrogen-to-oil volume ratio was 700. Before use, the catalyst was pre-sulfurized at 300°C for 4 hours using a hydrogen sulfide-nitrogen mixture with a hydrogen sulfide volume fraction of 12%. The catalyst specific surface area was 358 m². 2 / g, pore volume 1.16cm 3 / g represents a multi-level gradient pore structure.

[0024] Evaluation results: After 180 days of reaction evaluation, the initial desulfurization rate was 99.8% after the reaction stabilized. The initial product bromine index was 9 mgBr / 100g. After 180 days of reaction, the catalyst specific surface area was 337 m². 2 / g, pore volume 0.85cm 3 / g, activity decrease rate 1.3%.

[0025] Comparative Example 1: A high-capacity, multi-level porous coarse benzene hydrogenation catalyst resistant to organosilicon poisoning, and its preparation method and utilization. The catalyst was prepared without multi-level channels (without adding a template agent), and no template agent was added during the preparation process. The catalyst composition and process conditions were the same as in Example 1.

[0026] The catalyst described above has a specific surface area of ​​231 m². 2 / g, pore volume 0.72cm 3 / g.

[0027] An application of a high-capacity, multi-hierarchical porous catalyst resistant to organosilicon poisoning in the hydrogenation of crude benzene is disclosed. This catalyst is used for the hydrogenation reaction of crude benzene (Si content 12 ppm, S content 750 ppm, bromine index 1100 mgBr / 100g, aromatics mass fraction 64%). The feedstock passes through a C9+ removal tower to remove heavy components, gums, and asphaltenes, and undergoes a pre-hydrogenation process before entering the crude benzene hydrogenation reaction unit. The reaction temperature is 290℃, the pressure is 2 MPa, and the liquid hourly space velocity is 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 700. Before using the catalyst, a hydrogen sulfide-nitrogen mixture with a hydrogen sulfide volume fraction of 9% is used to pre-sulfurize the catalyst at 320℃ for 5 hours.

[0028] Evaluation results: After 180 days of reaction evaluation, the initial desulfurization rate was 99.8% after the reaction stabilized. The initial product bromine index was 11 mgBr / 100g. After 180 days of reaction, the catalyst specific surface area was 210 m². 2 / g, pore volume is 0.63cm 3 / g, activity decrease rate 5.9%.

[0029] During use, the activity decreased significantly, as did the specific surface area and pore volume.

[0030] Comparative Example 2: A high-capacity, multi-level porous coarse benzene hydrogenation catalyst resistant to organosilicon poisoning, and its preparation method and utilization. The catalyst was prepared without the addition of alkaline earth metals, and no magnesium species were added during the preparation process. The other components of the catalyst and the process conditions were the same as in Example 1.

[0031] The catalyst described above has a specific surface area of ​​263 m². 2 / g, pore volume 1.07cm 3 / g.

[0032] An application of a high-capacity, multi-hierarchical porous catalyst resistant to organosilicon poisoning in the hydrogenation of crude benzene is disclosed. This catalyst is used for the hydrogenation reaction of crude benzene (Si content 12 ppm, S content 750 ppm, bromine index 1100 mgBr / 100g, aromatics mass fraction 64%). The feedstock passes through a C9+ removal tower to remove heavy components, gums, and asphaltenes, and undergoes a pre-hydrogenation process before entering the crude benzene hydrogenation reaction unit. The reaction temperature is 290℃, the pressure is 2 MPa, and the liquid hourly space velocity is 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 700. Before using the catalyst, a hydrogen sulfide-nitrogen mixture with a hydrogen sulfide volume fraction of 9% is used to pre-sulfurize the catalyst at 320℃ for 5 hours.

[0033] Evaluation results: After 180 days of reaction evaluation, the initial desulfurization rate was 99.6% after the reaction stabilized. The initial product bromine index was 15 mgBr / 100g. After 180 days of reaction, the catalyst specific surface area was 228 m². 2 / g, pore volume is 0.87cm 3 / g, activity decrease rate 7.0%.

[0034] During use, the activity decreased significantly, as did the specific surface area and pore volume.

[0035] Comparative Example 3: A high-capacity, multi-level porous coarse benzene hydrogenation catalyst resistant to organosilicon poisoning, and its preparation method and utilization. The catalyst was prepared without the addition of Zr, and no zirconium species were added during the preparation process. The other components of the catalyst and the process conditions were the same as in Example 1.

[0036] The catalyst described above has a specific surface area of ​​354 m². 2 / g, pore volume 1.04cm 3 / g.

[0037] An application of a high-capacity, multi-hierarchical porous catalyst resistant to organosilicon poisoning in the hydrogenation of crude benzene is disclosed. This catalyst is used for the hydrogenation reaction of crude benzene (Si content 12 ppm, S content 750 ppm, bromine index 1100 mgBr / 100g, aromatics mass fraction 64%). The feedstock passes through a C9+ removal tower to remove heavy components, gums, and asphaltenes, and undergoes a pre-hydrogenation process before entering the crude benzene hydrogenation reaction unit. The reaction temperature is 290℃, the pressure is 2 MPa, and the liquid hourly space velocity is 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 700. Before using the catalyst, a hydrogen sulfide-nitrogen mixture with a hydrogen sulfide volume fraction of 9% is used to pre-sulfurize the catalyst at 320℃ for 5 hours.

[0038] Evaluation results: After 180 days of reaction evaluation, the initial desulfurization rate was 99.3% after the reaction stabilized. The initial product bromine index was 12 mgBr / 100g. After 180 days of reaction, the catalyst specific surface area was 311 m². 2 / g, pore volume is 0.71cm 3 / g, activity decrease rate 7.2%.

[0039] During use, the activity decreased significantly, as did the specific surface area and pore volume.

[0040] Comparative Example 4: A high-capacity, multi-hierarchical porous coarse benzene hydrogenation catalyst resistant to organosilicon poisoning, and its preparation method and utilization. The catalyst was prepared without the addition of Si, and no silicon species were added during the preparation process. The other components of the catalyst and the process conditions were the same as in Example 1.

[0041] The catalyst described above has a specific surface area of ​​340 m². 2 / g, pore volume is 0.96cm 3 / g.

[0042] An application of a high-capacity, multi-hierarchical porous catalyst resistant to organosilicon poisoning in the hydrogenation of crude benzene is disclosed. This catalyst is used for the hydrogenation reaction of crude benzene (Si content 12 ppm, S content 750 ppm, bromine index 1100 mgBr / 100g, aromatics mass fraction 64%). The feedstock passes through a C9+ removal tower to remove heavy components, gums, and asphaltenes, and undergoes a pre-hydrogenation process before entering the crude benzene hydrogenation reaction unit. The reaction temperature is 290℃, the pressure is 2 MPa, and the liquid hourly space velocity is 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 700. Before using the catalyst, a hydrogen sulfide-nitrogen mixture with a hydrogen sulfide volume fraction of 9% is used to pre-sulfurize the catalyst at 320℃ for 5 hours.

[0043] Evaluation results: After 180 days of reaction evaluation, the initial desulfurization rate was 97.9% after the reaction stabilized. The initial product bromine index was 17 mgBr / 100g. After 180 days of reaction, the catalyst specific surface area was 292 m². 2 / g, pore volume 0.68cm 3 / g, activity decrease rate 8.1%.

[0044] During use, the activity decreased significantly, as did the specific surface area and pore volume.

[0045] Comparative Example 5: A conventional catalyst, a high-capacity silica hierarchical porous crude benzene hydrogenation catalyst resistant to organosilicon poisoning, and its preparation method and utilization. The conventional industrial catalyst uses unmodified γ-alumina as a support, and the other components of the catalyst and process conditions are the same as in Example 1.

[0046] An application of a high-capacity, multi-hierarchical porous catalyst resistant to organosilicon poisoning in the hydrogenation of crude benzene is disclosed. This catalyst is used for the hydrogenation reaction of crude benzene (Si content 12 ppm, S content 750 ppm, bromine index 1100 mgBr / 100g, aromatics mass fraction 64%). The feedstock passes through a C9+ removal tower to remove heavy components, gums, and asphaltenes, and undergoes a pre-hydrogenation process before entering the crude benzene hydrogenation reaction unit. The reaction temperature is 290℃, the pressure is 2 MPa, and the liquid hourly space velocity is 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 700. Before using the catalyst, a hydrogen sulfide-nitrogen mixture with a hydrogen sulfide volume fraction of 9% is used to pre-sulfurize the catalyst at 320℃ for 5 hours.

[0047] Evaluation results: After 180 days of reaction evaluation, the initial desulfurization rate was 96.2% after the reaction stabilized. The initial product bromine index was 21 mgBr / 100g. After 180 days of reaction, the catalyst specific surface area was 184 m². 2 / g, pore volume 0.40cm 3 / g, activity decrease rate 20.8%.

[0048] The initial difference was large, and during use, the activity decreased significantly, as did the specific surface area and pore volume.

Claims

1. A high-capacity, multi-level porous crude benzene hydrogenation catalyst resistant to organosilicon poisoning, characterized in that: The catalyst has a multi-level gradient pore structure consisting of a composite support, a main active metal, and molybdenum oxide, and a specific surface area of ​​280-380 m². 2 / g, pore volume 0.8-1.3cm 3 / g; The composite support is a composite support formed by γ-Al2O3, SiO3, ZrO3, and MgO. Based on the total weight of the catalyst, the SiO2 content is 7.0-8.0 wt%, the ZrO2 content is 10.0-12.0 wt%, and the MgO content is 1.0-2.0 wt%. The main active metals are CoO and MoO3, with CoO accounting for 3.0-6.0 wt% and MoO3 accounting for 8.0-14.0 wt% of the total catalyst weight.

2. A high-capacity, multi-level porous coarse benzene hydrogenation catalyst resistant to organosilicon poisoning according to claim 1, characterized in that: The multi-level gradient pore structure is a multi-level gradient pore composed of macropores, mesopores and micropores, wherein the macropore diameter is greater than 50 nm and less than or equal to 200 nm, the mesopore diameter is greater than 8 nm and less than or equal to 50 nm, and the micropore diameter is less than or equal to 8 nm.

3. A method for preparing the catalyst according to claim 1, characterized in that: Includes the following steps: Step 1, Raw material selection: Aluminum nitrate is used as the aluminum source, tetraethyl orthosilicate (TEOS) is used as the silicon source, zirconium nitrate is used as the zirconium source, magnesium nitrate is used as the magnesium source, P123 is used as the mesoporous template agent, and soluble starch is used as the macroporous template agent. Step 2, Preparation of precursor solution: According to the catalyst composition, dissolve aluminum nitrate, tetraethyl orthosilicate (TEOS), zirconium nitrate, and magnesium nitrate in a 23-27 wt% ethanol aqueous solution; the solid components (aluminum nitrate, TEOS, zirconium nitrate, and magnesium nitrate) account for 18-21 wt% of the mass in the ethanol aqueous solution; Step 3: Add template agent: Add P123 to the solution and dissolve it completely, then add soluble starch and stir to disperse evenly; wherein P123 accounts for 9-11% of the solid phase mass, and starch accounts for 7.5-8.5% of the total solid phase mass; Step 4, co-precipitation: At 20-30℃, slowly add dilute ammonia to the solution to adjust the pH of the system to 9.0-9.5, and continue stirring to form a uniform composite hydroxide gel; Step 5, hydrothermal aging: Transfer to a hydrothermal autoclave and keep at 105-115℃ for 8-10 hours to stabilize the skeleton and pre-form the multi-level channels; Step 6, Precursor Post-processing: Static aging, allow natural static aging for 16-24 hours to allow the components to fully mix and blend; Wash and filter, wash with deionized water until neutral to remove free salt ions; Dry at 100-110℃ for 10-12 hours, sieve through 100-120 mesh to obtain powder; Step 7, Extrusion Molding: Based on the above powder mass, add guar gum powder (2.5-4 wt% of powder mass); add boehmite (12-15 wt% of powder mass); add 65-68 wt% concentrated nitric acid (1.5-3 wt% of powder mass); add deionized water (35-45 wt% of powder mass); mix evenly, extrude into strips; dry at 100-110℃ for 10-12 h; calcine at 500-520℃ for 5-8 h to obtain the composite carrier; Step 8: Loading of active components: According to the catalyst composition, prepare a mixed solution of cobalt nitrate and ammonium heptamolybdate. Impregnate the composite support in the mixed solution of cobalt nitrate and ammonium heptamolybdate with an equal volume. After impregnation, dry at 100-110℃ for 10-12h and calcine at 500-520℃ for 5-8h to obtain the catalyst. In the mixed solution of cobalt nitrate and ammonium heptamolybdate, the concentration of ammonium heptamolybdate is 10-17wt% and the concentration of cobalt nitrate is 5-12wt%.

4. The application of the catalyst as described in claim 1, characterized in that: It is used for the hydrogenation reaction of crude benzene, with a reaction temperature of 270-340℃, a pressure of 1.5-3.5MPa, and a liquid hourly space velocity of 1.5-2.5h⁻¹. -1 The hydrogen-to-oil volume ratio is 600-900. Before using the catalyst, a H2S-N2 mixture with a volume fraction of 9-12% H2S is used to pre-sulfurize the catalyst at 300-320℃ for 4-6 hours.