A solid core-shell diesel hydroprocessing catalyst with a selective shell loading of an active phase and a method for its preparation

Abstract

The present application provides a kind of solid core-shell diesel hydrogenation treatment catalyst of selective shell layer loaded metal phase and its preparation method, it is related to diesel hydrogenation catalyst field.The catalyst is with Ni, Mo as active component, with 4-nitrobenzenethiol and ethylenediamine as chelating agent, with mesoporous carbon@ molecular sieve material with solid core-shell structure as carrier.Its steps include: preparation solution A containing 4-nitrobenzenethiol, ethylenediamine and nickel salt and solution B containing 4-nitrobenzenethiol, ethylenediamine and molybdenum salt;Mesoporous carbon@ molecular sieve powder material with solid core-shell structure is weighed, and is immersed, filtered, dried and calcined in solution A and solution B in order, to obtain a kind of solid core-shell diesel hydrogenation treatment catalyst of selective shell layer loaded metal phase.

Description

Technical Field

[0001] This invention relates to the field of diesel hydrotreating catalysts, specifically to a solid core-shell diesel hydrotreating catalyst with a selectively shell-supported metal phase and its preparation method. Background Technology

[0002] The purpose of diesel hydrotreating to produce clean diesel is to maximize desulfurization, denitrification, and aromatics removal, and to increase the cetane number. The most crucial element is the selection of a targeted and highly efficient catalyst. Currently, hydrodesulfurization, denitrification, and aromatics removal, along with increasing the cetane number, are achieved through the hydrorefining function and hydrocracking function of the catalyst, respectively. The former utilizes a metal catalyst to hydrogenate aromatics to saturate and generate cycloalkanes while simultaneously removing sulfur and nitrogen, while the latter utilizes an acidic catalyst to perform ring-opening cracking of cycloalkanes.

[0003] Currently, industrial applications mainly employ three processes: single-reactor layered loading of two catalysts (single-stage dual-catalyst), dual-reactor layered loading of two catalysts (dual-stage dual-catalyst), or single-reactor single-catalyst loading (single-stage single-catalyst). However, all three have significant drawbacks. The first two processes involve high catalyst and equipment costs, complex process flows, and the hydrorefining and hydrocracking functions of the catalyst do not fully leverage their synergistic effects at the microscale. In the latter process, the disordered mixing of acidic supports (e.g., molecular sieves) and other supports (e.g., alumina or carbon) in the catalyst results in similarly disordered contact between the hydrorefining and hydrocracking functions at the microscale, failing to fully utilize their synergistic effects. Therefore, the development of multifunctional coupled catalysts that orderly integrate hydrorefining and hydrocracking functions is particularly urgent.

[0004] CN115646534B describes a method for treating microporous molecular sieves by silanizing them. Tetraethyl orthosilicate and dopamine are used to form a carbon coating layer on the outer surface of the molecular sieve. Further treatment involves calcination, HF etching, and a second drying and calcination process to obtain a mesoporous carbon@molecular sieve material with a solid core-shell structure. This invention provides a mesoporous carbon@molecular sieve material with a solid core-shell structure that combines mesoporous carbon and molecular sieves into a uniform, core-shell shaped single-particle material with clearly defined inner and outer layer boundaries.

[0005] Based on CN115646534B, this invention utilizes the chemical interaction of 4-nitrobenzenethiol, ethylenediamine, and Ni and Mo to form metal-organic chelates, increasing the molecular volume of the active metal component in solution. This selectively loads the active component into the mesoporous channels of mesoporous carbon, restricting its loading behavior within the microporous molecular sieve channels. The result is a solid core-shell diesel hydrotreating catalyst with a selectively shell-supported metal phase, exhibiting clearly defined and orderly connected functional boundaries between hydrorefining and hydrocracking. Summary of the Invention

[0006] This invention proposes a solid core-shell diesel hydrotreating catalyst with selectively supported metal phase and its preparation method, which solves the problem of orderly connection between hydrorefining and hydrocracking functions in diesel hydrotreating catalysts.

[0007] The technical solution of the present invention is as follows:

[0008] This invention proposes a solid core-shell diesel hydrotreating catalyst with selectively supported metal phases, using Ni-Mo as the active component, 4-nitrobenzenethiol and ethylenediamine as chelating agents, and mesoporous carbon@molecular sieve material with a solid core-shell structure as the support. The loading of the active component in the catalyst is 15-25%.

[0009] As a further technical solution, the mesoporous carbon@molecular sieve material with a solid core-shell structure is prepared by the following method: microporous molecular sieve, trimethylchlorosilane and toluene are mixed and reacted in microwave, filtered, washed and dried to obtain silanized molecular sieve, the silanized molecular sieve is dispersed in a mixture of anhydrous ethanol, ammonia and water, tetraethyl orthosilicate and dopamine are added, the mixture is stirred in microwave, centrifuged, washed, dried and calcined in nitrogen to obtain solid powder, the solid powder is then treated with HF solution, filtered, washed, dried and calcined to obtain the mesoporous carbon@molecular sieve material with a solid core-shell structure.

[0010] As a further technical solution, the solution impregnation refers to: adding the nickel salt, 4-nitrobenzenethiol and ethylenediamine to water and stirring to dissolve to obtain solution A; adding the molybdenum salt, 4-nitrobenzenethiol and ethylenediamine to water and stirring to dissolve to obtain solution B; and impregnating, filtering, drying and calcining the carrier in solution A and solution B in sequence.

[0011] As a further technical solution, the molar ratio of 4-nitrobenzenethiol to ethylenediamine is 2:1.

[0012] As a further technical solution, the calcination conditions after the carrier is impregnated, filtered, and dried in solution A are calcination at 400-450℃ in air for 1-2 hours, and the calcination conditions after the carrier is impregnated, filtered, and dried in solution B are calcination at 400-450℃ in 10% H2S / nitrogen for 3-5 hours. The drying conditions are all drying at 80-100℃ in air for 3-5 hours.

[0013] As a further technical solution, the mass ratio of Ni to Mo in the active component is (2-4):(6-9).

[0014] The basic principle of this invention is as follows: The mesoporous carbon@molecular sieve support with a solid core-shell structure is a single core-shell particle with a uniform structure and clearly defined inner and outer layer boundaries. The core is a microporous molecular sieve with a pore size of approximately 0.65 nm, and the shell is mesoporous carbon with a pore size greater than 5 nm. Through the chemical interaction of 4-nitrobenzenethiol, ethylenediamine, and Ni / Mo forming metal-organic chelates, the molecular volume of the active metal component in solution is increased. This selectively loads the active component into the mesoporous channels of the mesoporous carbon, restricting its loading behavior within the microporous molecular sieve channels. This results in a solid core-shell diesel hydrotreating catalyst with clearly defined and orderly connected functional boundaries for hydrorefining and hydrocracking. In the catalyst, the shell region of the mesoporous carbon-supported active component performs hydrodesulfurization, denitrification, and dearomatization functions on sulfur- and nitrogen-containing compounds and aromatic compounds in diesel fuel, while the molecular sieve core performs isomerization and cracking functions on the alkanes and cycloalkanes after desulfurization, denitrification, and dearomatization transferred from the shell region to improve the cetane number.

[0015] Compared with existing technologies, the solid core-shell diesel hydrotreating catalyst with selectively supported metal phase provided by this invention is a core-shell single catalyst that isolates but orderly connects the hydrorefining and hydrocracking functions in separate regions. Using this catalyst in diesel hydrotreating reactions is beneficial for further elucidating the transport mechanism of probe molecules and the reaction relay mechanism in different functional regions, and for a deeper understanding of the structure-activity relationship between the catalyst's microstructure and the macroscopic performance of hydrotreating. The catalyst can also avoid over-cracking caused by the aggregation of acidic supports, which is beneficial for improving the liquid yield of diesel after hydrotreating. Attached Figure Description

[0016] Figure 1 This is a graph showing the comparison and evaluation results of the catalytic effects of catalyst 5 prepared in Example 5 and three control catalysts. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1: A solid core-shell diesel hydrotreating catalyst with a selectively shell-supported metal phase was prepared by the following method: (1) 1.0 g of HY molecular sieve, 30 g of trimethylchlorosilane, and 20 g of toluene were mixed evenly and reacted with microwave at 30 °C for 4 h. After filtration, the mixture was washed with anhydrous ethanol until chloride ions were removed and dried at 100 °C to obtain silanized HY molecular sieve. 0.12 g of silanized HY molecular sieve was dispersed in a mixture of 10 ml of anhydrous ethanol and 40 ml of water and stirred at room temperature for 20 min. 0.5 ml of ammonia was added dropwise and stirred for 10 min. Then 0.5 ml of tetraethyl orthosilicate and 0.6 g of dopamine were added dropwise and stirred with microwave for 12 h. The mixture was centrifuged and washed 3 times and dried at 60 °C to obtain a brown powder. Under argon protection, the temperature was increased to 200 °C at 10 °C / min (and held for 0.5 h), and then increased to 800 °C at 3 °C / min (and held for 3 h) to obtain a black powder. The above material was added to 10 ml of 2% HF solution and stirred for 10 min. After centrifugation and washing, the material was dried at 100 ℃ and calcined at 450 ℃ for 2 h to obtain a mesoporous carbon@molecular sieve support with a solid core-shell structure.

[0019] (2) Add 0.25g nickel acetate, 0.31g 4-nitrobenzenethiol and 0.06g ethylenediamine to 2.5ml water and stir to dissolve to obtain solution A. Add 0.28g ammonium molybdate, 0.44g 4-nitrobenzenethiol and 0.09g ethylenediamine to 2.5ml water and stir to dissolve to obtain solution B.

[0020] (3) 0.74 g of mesoporous carbon@molecular sieve support with a solid core-shell structure was placed in solution A and stirred at room temperature for 12 h, filtered, dried in air at 100 °C for 3 h, and calcined in air at 450 °C for 2 h. It was then placed in solution B and stirred at room temperature for 12 h, filtered, dried in air at 100 °C for 3 h, and calcined in nitrogen with a hydrogen sulfide volume content of 10% at 450 °C for 4 h to obtain a solid core-shell diesel hydrotreating catalyst with a selective shell-supported metal phase.

[0021] Example 2: A solid core-shell diesel hydrotreating catalyst with a selectively shell-supported metal phase was prepared by the following method: (1) 1.0 g Beta molecular sieve, 30 g trimethylchlorosilane, and 20 g toluene were mixed evenly and reacted with microwave at 30 °C for 4 h. After filtration, the mixture was washed with anhydrous ethanol until chloride ions were removed and dried at 100 °C to obtain silanized Beta molecular sieve. 0.12 g of silanized Beta molecular sieve was dispersed in a mixture of 10 ml anhydrous ethanol and 40 ml water and stirred at room temperature for 20 min. 0.5 ml ammonia was added dropwise and stirred for 10 min. Then 0.5 ml tetraethyl orthosilicate and 0.6 g dopamine were added dropwise and stirred with microwave for 12 h. The mixture was centrifuged and washed 3 times and dried at 60 °C to obtain a brown powder. Under argon protection, the temperature was increased to 200 °C at 10 °C / min (held at 0.5 h) and increased to 800 °C at 3 °C / min (held at 3 h) to obtain a black powder. The above materials were added to 10 ml of 2% HF solution and stirred for 10 min. After centrifugation and washing, the mixture was dried at 100 ℃ and calcined at 450 ℃ for 2 h to obtain a mesoporous carbon@molecular sieve support with a solid core-shell structure.

[0022] (2) Add 0.25g nickel acetate, 0.31g 4-nitrobenzenethiol and 0.06g ethylenediamine to 2.5ml water and stir to dissolve to obtain solution A. Add 0.28g ammonium molybdate, 0.44g 4-nitrobenzenethiol and 0.09g ethylenediamine to 2.5ml water and stir to dissolve to obtain solution B.

[0023] (3) 0.74 g of mesoporous carbon@molecular sieve support with a solid core-shell structure was placed in solution A and stirred at room temperature for 12 h, filtered, dried in air at 100 °C for 3 h, and calcined in air at 450 °C for 2 h. It was then placed in solution B and stirred at room temperature for 12 h, filtered, dried in air at 100 °C for 3 h, and calcined in nitrogen with a hydrogen sulfide volume content of 10% at 450 °C for 4 h to obtain a solid core-shell diesel hydrotreating catalyst with a selective shell-supported metal phase.

[0024] Example 3: A solid core-shell diesel hydrotreating catalyst with a selectively shell-supported metal phase was prepared by the following method: (1) 1.0 g of HZSM-5 molecular sieve, 30 g of trimethylchlorosilane, and 20 g of toluene were mixed evenly and reacted with microwave at 30 °C for 4 h. The mixture was filtered, washed with anhydrous ethanol until no chloride ions were found, and dried at 100 °C to obtain silanized HZSM-5 molecular sieve. 0.12 g of silanized HZSM-5 molecular sieve was dispersed in a mixture of 10 ml of anhydrous ethanol and 40 ml of water and stirred at room temperature for 20 min. 0.5 ml of ammonia was added dropwise and stirred for 10 min. Then 0.5 ml of tetraethyl orthosilicate and 0.6 g of dopamine were added dropwise and stirred with microwave for 12 h. The mixture was centrifuged and washed three times, then dried at 60°C to obtain a brown powder. Under argon protection, the powder was heated to 200°C at a rate of 10°C / min (and held at that temperature for 0.5 h), and then heated to 800°C at a rate of 3°C / min (and held at that temperature for 3 h) to obtain a black powder. The above material was added to 10 ml of 2% HF solution and stirred for 10 min. After centrifugation and washing twice, the mixture was dried at 100°C and calcined at 450°C for 2 h to obtain a mesoporous carbon@molecular sieve support with a solid core-shell structure.

[0025] (2) Add 0.25g nickel acetate, 0.31g 4-nitrobenzenethiol and 0.06g ethylenediamine to 2.5ml water and stir to dissolve to obtain solution A. Add 0.28g ammonium molybdate, 0.44g 4-nitrobenzenethiol and 0.09g ethylenediamine to 2.5ml water and stir to dissolve to obtain solution B.

[0026] (3) 0.74 g of mesoporous carbon@molecular sieve support with a solid core-shell structure was placed in solution A and stirred at room temperature for 12 h, filtered, dried in air at 100 °C for 3 h, and calcined in air at 450 °C for 2 h. It was then placed in solution B and stirred at room temperature for 12 h, filtered, dried in air at 100 °C for 3 h, and calcined in nitrogen with a hydrogen sulfide volume content of 10% at 450 °C for 4 h to obtain a solid core-shell diesel hydrotreating catalyst with a selective shell-supported metal phase.

[0027] Example 4: A solid core-shell diesel hydrotreating catalyst with a selectively shell-supported metal phase was prepared by the following method: (1) 1.0 g of HY molecular sieve, 30 g of trimethylchlorosilane, and 20 g of toluene were mixed evenly and reacted with microwave at 30 °C for 4 h. The mixture was filtered, washed with anhydrous ethanol until chloride ions were removed, and dried at 100 °C to obtain silanized HY molecular sieve. 0.12 g of silanized HY molecular sieve was dispersed in a mixture of 10 ml of anhydrous ethanol and 40 ml of water and stirred at room temperature for 20 min. 0.5 ml of ammonia was added dropwise and stirred for 10 min. Then 0.5 ml of tetraethyl orthosilicate and 0.6 g of dopamine were added dropwise and stirred with microwave for 12 h. The mixture was centrifuged and washed 3 times, dried at 60 °C to obtain a brown powder, and heated to 200 °C at 10 °C / min (held at 0.5 h) under argon protection, and then heated to 800 °C at 3 °C / min (held at 3 h) to obtain a black powder. The above material was added to 10 ml of 2% HF solution and stirred for 10 min. After centrifugation and washing, the material was dried at 100 ℃ and calcined at 450 ℃ for 2 h to obtain a mesoporous carbon@molecular sieve support with a solid core-shell structure.

[0028] (2) Add 0.21g nickel acetate, 0.29g 4-nitrobenzenethiol and 0.05g ethylenediamine to 2.5ml water and stir to dissolve to obtain solution A. Add 0.33g ammonium molybdate, 0.48g 4-nitrobenzenethiol and 0.10g ethylenediamine to 2.5ml water and stir to dissolve to obtain solution B.

[0029] (3) 0.74 g of mesoporous carbon@molecular sieve support with a solid core-shell structure was placed in solution A and stirred at room temperature for 12 h, filtered, dried in air at 100 °C for 3 h, and calcined in air at 450 °C for 2 h. It was then placed in solution B and stirred at room temperature for 12 h, filtered, dried in air at 100 °C for 3 h, and calcined in nitrogen with a hydrogen sulfide volume content of 10% at 450 °C for 4 h to obtain a solid core-shell diesel hydrotreating catalyst with a selective shell-supported metal phase.

[0030] Example 5: A solid core-shell diesel hydrotreating catalyst with a selectively shell-supported metal phase was prepared by the following method: (1) 1.0 g of HY molecular sieve, 30 g of trimethylchlorosilane, and 20 g of toluene were mixed evenly and reacted with microwave at 30 °C for 4 h. The mixture was filtered, washed with anhydrous ethanol until chloride ions were removed, and dried at 100 °C to obtain silanized HY molecular sieve. 0.12 g of silanized HY molecular sieve was dispersed in a mixture of 10 ml of anhydrous ethanol and 40 ml of water and stirred at room temperature for 20 min. 0.5 ml of ammonia was added dropwise and stirred for 10 min. Then 0.5 ml of tetraethyl orthosilicate and 0.6 g of dopamine were added dropwise and stirred with microwave for 12 h. The mixture was centrifuged and washed 3 times, dried at 60 °C to obtain a brown powder, and heated to 200 °C at 10 °C / min (held at 0.5 h) under argon protection, and then heated to 800 °C at 3 °C / min (held at 3 h) to obtain a black powder. The above material was added to 10 ml of 2% HF solution and stirred for 10 min. After centrifugation and washing, the material was dried at 100 ℃ and calcined at 450 ℃ for 2 h to obtain a mesoporous carbon@molecular sieve support with a solid core-shell structure.

[0031] (2) Add 0.25g nickel acetate, 0.31g 4-nitrobenzenethiol and 0.06g ethylenediamine to 2.5ml water and stir to dissolve to obtain solution A. Add 0.28g ammonium molybdate, 0.44g 4-nitrobenzenethiol and 0.09g ethylenediamine to 2.5ml water and stir to dissolve to obtain solution B.

[0032] (3) 0.74 g of mesoporous carbon@molecular sieve support with a solid core-shell structure was placed in solution A and stirred at room temperature for 12 h, filtered, dried in air at 100 °C for 3 h, and calcined in air at 400 °C for 1 h. It was then placed in solution B and stirred at room temperature for 12 h, filtered, dried in air at 100 °C for 3 h, and calcined in nitrogen gas with a hydrogen sulfide volume content of 10% at 400 °C for 2 h to obtain a solid core-shell diesel hydrotreating catalyst with a selective shell-supported metal phase.

[0033] Example 6: A control catalyst was prepared by the following method: (1) 0.25 g of nickel acetate was added to 2.5 ml of water and stirred to dissolve to obtain solution A, and 0.28 g of ammonium molybdate was added to 2.5 ml of water and stirred to dissolve to obtain solution B.

[0034] (2) 0.74 g of mesoporous carbon CMK-3 was placed in solution A and stirred at room temperature for 12 h, filtered, dried in air at 100 °C for 3 h, and calcined in air at 400 °C for 1 h. It was then placed in solution B and stirred at room temperature for 12 h, filtered, dried in air at 100 °C for 3 h, and calcined in nitrogen gas with a hydrogen sulfide volume content of 10% at 400 °C for 2 h to obtain control catalyst 1.

[0035] Example 7: A control catalyst was prepared by the following method: (1) 0.25 g of nickel acetate was added to 2.5 ml of water and stirred to dissolve to obtain solution A, and 0.28 g of ammonium molybdate was added to 2.5 ml of water and stirred to dissolve to obtain solution B.

[0036] (2) Place 0.74g of HY molecular sieve in solution A and stir at room temperature for 12h. Filter, dry in air at 100℃ for 3h, and calcine in air at 400℃ for 1h. Continue to place in solution B and stir at room temperature for 12h. Filter, dry in air at 100℃ for 3h, and calcine in nitrogen gas with a hydrogen sulfide volume content of 10% at 400℃ for 2h to obtain control catalyst 2.

[0037] Example 8: A control catalyst was prepared by the following method: (1) HY type molecular sieve and mesoporous carbon CMK-3 (mass ratio of 1:3) were carefully ground in an agate mortar and mixed evenly to obtain a mixed support.

[0038] (2) Add 0.25g of nickel acetate to 2.5ml of water and stir to dissolve to obtain solution A. Add 0.28g of ammonium molybdate to 2.5ml of water and stir to dissolve to obtain solution B.

[0039] (3) Place 0.74 g of the mixed support in solution A and stir at room temperature for 12 h, filter, dry in air at 100 °C for 3 h, and calcine in air at 400 °C for 1 h. Continue to place in solution B and stir at room temperature for 12 h, filter, dry in air at 100 °C for 3 h, and calcine in nitrogen gas with a hydrogen sulfide volume content of 10% at 400 °C for 2 h to obtain control catalyst 3.

[0040] Example 9: This example evaluates catalyst 5, control catalyst 1, control catalyst 2, and control catalyst 3 provided in the above examples using a 100mL small-scale batch reactor. 1.4 g of catalyst was added to the reactor, and the temperature was gradually increased to 300 °C under a hydrogen atmosphere. The feedstock was a toluene solution of dibenzothiophene, with a dibenzothiophene mass ratio of 5%. The reaction conditions were: reaction pressure 4.0 MPa, reaction temperature 300 °C, and reaction time 72 h. The comparative evaluation results of the catalytic effects of catalyst 5, control catalyst 1, control catalyst 2, and control catalyst 3 are shown in Table 1. Table 1 shows that the catalyst provided by this invention has a higher conversion rate of dibenzothiophene than the control catalyst, and the yield and selectivity of cyclohexylbenzene (CHB) are also higher than the control catalyst. This indicates that the catalyst provided by this invention is more conducive to the removal of dibenzothiophene, more conducive to the hydrogenation pathway of dibenzothiophene, and beneficial to improving the cetane number and quality of diesel products.

[0041] Table 1. Comparison and evaluation results of the catalytic effects of the catalyst prepared in Example 5 and three control catalysts.

[0042] catalyst Dibenzothiophene conversion rate CHB Selectivity CHB Yield Catalyst 5 90.4 95.4 80.2 Reference catalyst 1 57.2 63.2 57 Reference catalyst 2 63.9 11.3 6.4 Reference catalyst 3 83.5 89.1 72.5

Claims

1. A solid core-shell diesel hydroprocessing catalyst of the type selective shell supported metal phase, characterized in that, Using Ni and Mo as active components, 4-nitrophenylthiol and ethylenediamine as chelating agents, and mesoporous carbon@molecular sieve material with a solid core-shell structure as a support, the active components and chelating agents are loaded onto the support using a solution impregnation method. The catalyst is obtained by filtration, drying, and calcination, with the active component loading in the catalyst being 15%-25%. The solution impregnation method involves: adding nickel salt, 4-nitrophenylthiol, and ethylenediamine to water and stirring to dissolve, obtaining solution A; adding molybdenum salt, 4-nitrophenylthiol, and ethylenediamine to water and stirring to dissolve, obtaining solution B; and then impregnating, filtering, drying, and calcining the support in solutions A and B in sequence.

2. The diesel hydroprocessing catalyst of claim 1, wherein, The mass ratio of Ni to Mo in the active component is (2-4):(6-9).

3. The diesel hydrotreating catalyst according to claim 1, characterized in that, The molar ratio of 4-nitrobenzenethiol to ethylenediamine is 2:

1.

4. The diesel hydrotreating catalyst according to claim 1, characterized in that, The carrier, after being impregnated, filtered, and dried in solution A, is calcined in air at 400℃-450℃ for 1-2 hours. The carrier, after being impregnated, filtered, and dried in solution B, is calcined in nitrogen gas with a hydrogen sulfide volume content of 10% at 400℃-450℃ for 3-5 hours. All drying is carried out in air at 80℃-100℃ for 3-5 hours.

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