Low-temperature aromatic hydrocarbon saturated non-noble metal catalyst as well as preparation method and application thereof

Abstract

The invention provides a low-temperature aromatic hydrocarbon saturated non-noble metal catalyst as well as a preparation method and application thereof. The catalyst Ni / CeAlOx takes a cerium-aluminum composite oxide as a carrier and metal nickel as an active component, and has the advantages of nanoscale dispersion, high specific surface area and surface acidity of 150-165 umol / g, and the preparation method comprises the following steps: dissolving a nickel salt, a cerium salt, an aluminum salt and urea in deionized water, carrying out a hydrothermal reaction to obtain a precursor, and carrying out calcination and hydrogen reduction to obtain the catalyst Ni / CeAlOx. The catalyst does not need to be pre-vulcanized, does not contain noble metal, shows excellent deep hydrogenation activity and selectivity of aromatic hydrocarbon under the conditions of low temperature (130-280 DEG C) and low pressure (2.5 MPa), can realize complete conversion and decahydronaphthalene selectivity of over 96% for naphthalene hydrogenation, can efficiently treat a high-temperature coal tar complex system, greatly reduces the aromatic hydrocarbon content, and has a wide application prospect. The method has the advantages of low cost, environmental friendliness and the like, and provides an efficient catalytic solution for high-value utilization of coal tar.

Description

Technical Field

[0001] This invention relates to the field of petroleum catalytic hydrogenation technology, specifically to a low-temperature aromatic saturated non-precious metal catalyst, its preparation method, and its application. Background Technology

[0002] Aromatic hydrocarbon hydrogenation saturation is a key process in petroleum refining and deep processing of coal tar, and is of great significance for the production of clean fuels and high-value-added chemicals. As a major coke producer, my country generates a large amount of high-temperature coal tar annually as a byproduct, which is rich in polycyclic aromatic hydrocarbons such as naphthalene. Converting this tar into high-value cycloalkanes such as decahydronaphthalene through catalytic hydrogenation is an important pathway to achieving high-value utilization of coal tar.

[0003] Currently, cobalt-molybdenum or nickel-molybdenum sulfide catalysts widely used in industry, while possessing some hydrogenation capacity for compounds such as naphthalene, typically require operation at relatively high temperatures (200–500℃) and pressures (6–12 MPa). In real coal tar, similarly high temperatures (300–500℃) and high pressures (15–17 MPa) are required. These catalysts exhibit significantly insufficient activity under mild conditions, resulting in unsatisfactory selectivity for naphthalene hydrogenation. The reaction often stalls at the tetrahydronaphthalene stage, with tetrahydronaphthalene as the predominant product and low yields of decahydronaphthalene. Furthermore, pre-sulfurization treatment is necessary, a complex process prone to sulfur contamination, and the catalysts also suffer from sulfur deactivation. To reduce the severity of the reaction, researchers have attempted to use noble metal catalysts (such as platinum and palladium), which exhibit better low-temperature activity but are expensive and extremely sensitive to impurities such as sulfur and nitrogen in the feedstock, easily becoming poisoned and deactivated in high-temperature coal tar.

[0004] Non-precious metal nickel-based catalysts are low in cost, but existing systems also struggle to achieve both high activity and high hydrogenation selectivity under mild conditions. When applied to real high-temperature coal tar, the gums, asphaltenes, and heteroatom compounds in the feedstock can easily cause catalyst poisoning, carbon buildup, and pore blockage, leading to a significant decrease in their activity and stability.

[0005] Therefore, developing a novel non-precious metal catalyst that does not require pre-sulfurization, possesses both high aromatic hydrogenation activity and high deep hydrogenation selectivity under mild conditions, and can adapt to the complex system of real coal tar has become a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a low-temperature aromatic saturated non-precious metal catalyst, its preparation method and application, to solve the technical problem of "insufficient activity and poor selectivity of existing non-precious metal catalysts for deep hydrogenation of polycyclic aromatic hydrocarbons under mild conditions".

[0007] To achieve the above objectives, the present invention is implemented using the following technical solution: In a first aspect, the present invention provides a low-temperature aromatic saturated non-noble metal catalyst, wherein the catalyst is Ni / CeAlO x Using cerium-aluminum composite oxide as a support and metallic nickel as the active component, the catalyst has an average particle size of 5-6 nm and a specific surface area of ​​170-190 m². 2 / g, surface acidity is 150~165umol / g, Ce in the carrier 3+ The percentage is 0.18~0.25.

[0008] Secondly, the present invention provides a method for preparing a low-temperature aromatic saturated non-noble metal catalyst, comprising the following steps: (1) Dissolve nickel salt, cerium salt, aluminum salt and urea in deionized water, mix evenly, carry out hydrothermal reaction, and after the reaction, separate solid and liquid, wash and dry to obtain the precursor; (2) The above precursor was calcined at 200~600℃ and then reduced in a hydrogen atmosphere to obtain the catalyst Ni / CeAlO. x .

[0009] Specifically, in step (1), the amounts of nickel salt, cerium salt and aluminum salt satisfy the following molar ratio: Ni:(Ce+Al)=(1.5~3):1.

[0010] Specifically, in step (1), the amounts of cerium salt and aluminum salt satisfy the following molar ratio: Ce:Al = (0.1~1.8):0.9.

[0011] Specifically, in step (1), the molar ratio of urea to total metal ions (Ni+Ce+Al) is (2~4):1.

[0012] Specifically, in step (1), the amount of deionized water added makes the concentration of total metal ions (Ni+Ce+Al) in the reaction system 2.5~3.5 mol / L.

[0013] Specifically, the reduction temperature in step (2) is 500~600℃.

[0014] Thirdly, the present invention provides an application of a low-temperature aromatic saturated non-precious metal catalyst in the catalytic hydrogenation of naphthalene and high-temperature coal tar.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: (1) The Ni / CeAlO provided by the present invention x The catalyst can achieve complete hydrogenation conversion of naphthalene under low temperature and low pressure conditions, with a selectivity of over 96% for decahydronaphthalene, and the tetrahydronaphthalene intermediate is almost completely converted into decahydronaphthalene, breaking through the technical bottleneck of poor deep hydrogenation selectivity of traditional non-precious metal catalysts under mild conditions.

[0016] (2) The catalyst of the present invention does not require pre-sulfurization and does not contain precious metals, thus avoiding sulfur pollution and precious metal poisoning problems. It is environmentally friendly and significantly reduces costs. By combining Ce doping with urea hydrothermal method, high dispersion of Ni species and synergistic regulation of carrier acidity are achieved, which enhances the catalyst’s adsorption and hydrogenation capacity for polycyclic aromatic hydrocarbons.

[0017] (3) The catalyst of the present invention still exhibits excellent aromatic saturation capacity in the complex system of real high-temperature coal tar. Under the conditions of 280℃ and 2.5MPa H2, it can reduce the aromatic content in the feedstock from 74.1% to 28.8% and increase the saturated hydrocarbon content to more than 71.2%, providing an efficient and economical catalytic solution for the high-value conversion of coal tar. Attached Figure Description

[0018] Figure 1 These are TEM images, HRTEM images, and lattice spacing images of the catalyst prepared in Example 2 of this invention.

[0019] Figure 2 The images show the XRD patterns of the catalysts of Examples 2 and 1-3 of the present invention, as well as the catalyst precursors of Examples 2 and 1 and Comparative Examples 1. Detailed Implementation

[0020] 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.

[0021] This invention proposes a catalyst system with nickel (Ni) as the active component and cerium-aluminum composite oxide as the support. The catalyst is prepared by synthesizing a precursor via a urea-assisted hydrothermal method, followed by calcination and hydrogen reduction. By controlling the molar ratio of Ni, Ce, and Al and optimizing the reduction temperature, the deep hydrogenation performance of the catalyst under mild conditions is significantly enhanced. The introduction of Ce not only promotes the reduction and dispersion of Ni species but also enhances the oxygen storage capacity and surface acidity of the support, forming abundant oxygen vacancies and suitable acid-base sites. Under the optimized Ce / Al ratio, the catalyst forms a composite structure of highly dispersed Ni species, CeO2 crystalline phase, and amorphous Al2O3. The synergistic effect of these three components effectively promotes hydrogen activation, aromatic adsorption, and further hydrogenation conversion of intermediates, thereby achieving highly selective deep saturation of polycyclic aromatic hydrocarbons.

[0022] The catalyst provided by this invention does not require pre-sulfurization treatment and exhibits excellent aromatic hydrogenation activity and deep hydrogenation selectivity under low temperature and low pressure conditions. It is particularly suitable for high-temperature coal tar systems with complex compositions, providing an efficient, economical, and environmentally friendly catalytic solution for their high-value conversion.

[0023] In this invention, the specific surface area of ​​the catalyst was determined using the BET nitrogen adsorption method; the surface acidity was determined using the ammonia temperature-programmed desorption method (NH3-TPD), specifically: the sample was reduced at 500℃ in an H2 atmosphere, then NH3 was adsorbed at 120℃, and then desorbed by increasing the temperature to 800℃ at a rate of 10℃ / min. The total acidity was calculated using the external standard method, with units of μmol / g; Ce in the support... 3+ The proportion was determined by X-ray photoelectron spectroscopy (XPS). Specifically, the reduced catalyst sample was transferred to an XPS spectrometer in an inert atmosphere, and the Ce 3d spectrum was acquired. The Ce content was calculated by peak fitting. 3+ The ratio of peak area to total Ce 3d peak area.

[0024] A method for preparing a low-temperature aromatic saturated non-noble metal catalyst includes the following steps: (1) Weigh nickel chloride hexahydrate, cerium nitrate hexahydrate, aluminum nitrate nonahydrate and urea, place them in a container, add deionized water, the mass of deionized water is 0.5 to 1.5 times the total mass of all solid raw materials, stir and mix evenly, transfer the mixture to a hydrothermal reactor and seal it, react at 80 to 140°C for 2 to 6 hours, after the reaction is completed, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol, and dry it at 70 to 90°C for 4 to 8 hours to obtain precursor powder; (2) The precursor powder obtained above is placed in a muffle furnace and heated to 200-600°C at a heating rate of 5-15°C / min under an air atmosphere for 2-4 hours. After calcination, the obtained powder is transferred to a tube reduction furnace and heated at a heating rate of 5-15°C / min under a hydrogen atmosphere for 3-8 hours to obtain the Ni / CeAlO. x catalyst.

[0025] Preferably, the amounts of nickel chloride hexahydrate, cerium nitrate hexahydrate, and aluminum nitrate nonahydrate satisfy the following molar ratio: Ni:(Ce+Al)=(1.5~3):1, and more preferably Ni:(Ce+Al)=2:1.

[0026] Preferably, the amounts of cerium nitrate hexahydrate and aluminum nitrate nonahydrate satisfy the following molar ratio: Ce:Al = (0.1~1.8):0.9, and more preferably Ce:Al = 1:1.

[0027] Preferably, the molar ratio of urea to total metal ions (Ni+Ce+Al) is (2~4):1.

[0028] Preferably, the amount of deionized water added is such that the concentration of total metal ions (Ni+Ce+Al) in the reaction system is 2.5~3.5 mol / L.

[0029] Preferably, the reduction temperature of the tubular reduction furnace in step (2) is 500~600℃, and more preferably 550℃.

[0030] The application of a low-temperature aromatic saturated non-precious metal catalyst in the catalytic hydrogenation of naphthalene and high-temperature coal tar n-hexane includes the following steps: adding 100 mg of substrate and 25 mg of Ni / CeAlO₂... x The catalyst and 30 mL of n-hexane were added to a high-pressure reactor, sealed, and then purged with 2.5 MPa of hydrogen gas to react and obtain the product.

[0031] The substrate is naphthalene or high-temperature coal tar. When the substrate is naphthalene, the reaction temperature is 140~160℃ and the reaction time is 2h. When the substrate is high-temperature coal tar, the reaction temperature is 260~280℃ and the reaction time is 4h.

[0032] Example 1; (1) Weigh 18 mmol nickel chloride hexahydrate, 1.2 mmol cerium nitrate hexahydrate, 10.8 mmol aluminum nitrate nonahydrate and 4.2 g urea, put them in a container, add 10 mL deionized water, stir and mix evenly, transfer the mixture to a hydrothermal reactor and seal it, react at 130 °C for 3 h, after the reaction is completed, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol, dry it at 80 °C for 6 h to obtain the precursor powder; (2) The precursor powder obtained above was placed in a muffle furnace and heated to 300°C at a heating rate of 10°C / min under an air atmosphere and calcined for 3h. After calcination, the obtained powder was transferred to a tube reduction furnace and heated to 550°C at a heating rate of 10°C / min under a hydrogen atmosphere and reduced for 6h to obtain catalyst E1. (3) Add 100 mg naphthalene, 25 mg catalyst E1 and 30 mL n-hexane to a high-pressure reactor, seal it and fill it with 2.5 MPa of hydrogen gas. React at 160 °C for 2 h to obtain product L1.

[0033] Example 2; (1) Weigh 20 mmol nickel chloride hexahydrate, 5 mmol cerium nitrate hexahydrate, 5 mmol aluminum nitrate nonahydrate and 4.2 g urea, put them in a container, add 10 mL deionized water, stir and mix evenly, transfer the mixture to a hydrothermal reactor and seal it, react at 130 °C for 3 h, after the reaction is completed, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol, dry it at 80 °C for 6 h to obtain the precursor powder; (2) The precursor powder obtained above was placed in a muffle furnace and heated to 300°C at a heating rate of 10°C / min under an air atmosphere and calcined for 3h. After calcination, the obtained powder was transferred to a tube reduction furnace and heated to 550°C at a heating rate of 10°C / min under a hydrogen atmosphere and reduced for 6h to obtain catalyst E2. (3) Add 100 mg naphthalene, 25 mg catalyst E2 and 30 mL n-hexane to a high pressure vessel, seal it and fill it with 2.5 MPa of hydrogen gas. React at 150 °C for 2 h to obtain product L2.

[0034] Example 3; (1) Weigh 22.5 mmol nickel chloride hexahydrate, 5 mmol cerium nitrate hexahydrate, 2.5 mmol aluminum nitrate nonahydrate and 4.2 g urea, put them in a container, add 10 mL deionized water, stir and mix evenly, transfer the mixture to a hydrothermal reactor and seal it, react at 130 °C for 3 h, after the reaction is completed, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol, dry it at 80 °C for 6 h to obtain the precursor powder; (2) The precursor powder obtained above was placed in a muffle furnace and heated to 300°C at a heating rate of 10°C / min under an air atmosphere and calcined for 3h. After calcination, the obtained powder was transferred to a tube reduction furnace and heated to 550°C at a heating rate of 10°C / min under a hydrogen atmosphere and reduced for 6h to obtain catalyst E3. (3) Add 100 mg naphthalene, 25 mg catalyst E3 and 30 mL n-hexane to a high pressure vessel, seal it and fill it with 2.5 MPa of hydrogen gas. React at 140 °C for 2 h to obtain product L3.

[0035] Example 4; (1) Weigh 20 mmol nickel chloride hexahydrate, 5 mmol cerium nitrate hexahydrate, 5 mmol aluminum nitrate nonahydrate and 3.6 g urea, put them in a container, add 12 mL deionized water, stir and mix evenly, transfer the mixture to a hydrothermal reactor and seal it, react at 80 °C for 2 h, after the reaction is completed, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol, dry it at 70 °C for 4 h to obtain the precursor powder; (2) The precursor powder obtained above was placed in a muffle furnace and heated to 200°C at a heating rate of 5°C / min under an air atmosphere and calcined for 2 hours. After calcination, the obtained powder was transferred to a tube reduction furnace and heated to 500°C at a heating rate of 5°C / min under a hydrogen atmosphere and reduced for 3 hours to obtain catalyst E4. (3) Add 100 mg naphthalene, 25 mg catalyst E4 and 30 mL n-hexane to a high-pressure reactor, seal it and purge with 2.5 MPa of hydrogen gas, and react at 160 °C for 2 h to obtain product L4.

[0036] Example 5; (1) Weigh 20 mmol nickel chloride hexahydrate, 5 mmol cerium nitrate hexahydrate, 5 mmol aluminum nitrate nonahydrate and 7.2 g urea, put them in a container, add 8.57 mL deionized water, stir and mix evenly, transfer the mixture to a hydrothermal reactor and seal it, react at 140 °C for 6 h, after the reaction is completed, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol, dry it at 90 °C for 8 h to obtain the precursor powder; (2) The precursor powder obtained above was placed in a muffle furnace and heated to 600°C at a heating rate of 15°C / min under an air atmosphere and calcined for 4 hours. After calcination, the obtained powder was transferred to a tube reduction furnace and heated to 600°C at a heating rate of 15°C / min under a hydrogen atmosphere and reduced for 8 hours to obtain catalyst E5. (3) Add 100 mg naphthalene, 25 mg catalyst E5 and 30 mL n-hexane to a high pressure vessel, seal it and fill it with 2.5 MPa of hydrogen gas. React at 150 °C for 2 h to obtain product L5.

[0037] Example 6: 100 mg of high-temperature coal tar, 25 mg of catalyst E2 and 30 mL of n-hexane were added to a high-pressure reactor, sealed and charged with 2.5 MPa of hydrogen gas. The reaction was carried out at 260 °C for 4 h to obtain product L8.

[0038] Example 7: 100 mg of high-temperature coal tar, 25 mg of catalyst E2 and 30 mL of n-hexane were added to a high-pressure reactor, sealed and charged with 2.5 MPa of hydrogen gas. The reaction was carried out at 280 °C for 4 h to obtain product L9.

[0039] Comparative Example 1; (1) Weigh 20 mmol nickel chloride hexahydrate, 10 mmol aluminum nitrate nonahydrate and 4.2 g urea, put them in a container, add 10 mL deionized water, stir and mix evenly, transfer the mixture to a hydrothermal reactor and seal it, react at 130 °C for 3 h, after the reaction is completed, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol, dry it at 80 °C for 6 h to obtain the precursor powder; (2) The precursor powder obtained above was placed in a muffle furnace and heated to 300°C at a heating rate of 10°C / min under an air atmosphere and calcined for 3h. After calcination, the obtained powder was transferred to a tube reduction furnace and heated to 550°C at a heating rate of 10°C / min under a hydrogen atmosphere and reduced for 6h to obtain catalyst D1. (3) Add 100 mg naphthalene, 25 mg catalyst D1 and 30 mL n-hexane to a high-pressure reactor, seal it and fill it with 2.5 MPa of hydrogen gas. React at 150 °C for 2 h to obtain product M1.

[0040] Comparative Example 2; (1) Weigh 20 mmol nickel chloride hexahydrate, 9 mmol cerium nitrate hexahydrate, 1 mmol aluminum nitrate nonahydrate and 4.2 g urea, put them in a container, add 10 mL deionized water, stir and mix evenly, transfer the mixture to a hydrothermal reactor and seal it, react at 130 °C for 3 h, after the reaction is completed, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol, dry it at 80 °C for 6 h to obtain the precursor powder; (2) The precursor powder obtained above was placed in a muffle furnace and heated to 300°C at a heating rate of 10°C / min under an air atmosphere and calcined for 3h. After calcination, the obtained powder was transferred to a tube reduction furnace and heated to 550°C at a heating rate of 10°C / min under a hydrogen atmosphere and reduced for 6h to obtain catalyst D2. (3) Add 100 mg naphthalene, 25 mg catalyst D2 and 30 mL n-hexane to a high-pressure reactor, seal it and purge with 2.5 MPa of hydrogen gas, and react at 150 °C for 2 h to obtain product M2.

[0041] Comparative Example 3; (1) Weigh 20 mmol nickel chloride hexahydrate, 1 mmol cerium nitrate hexahydrate, 9 mmol aluminum nitrate nonahydrate and 4.2 g urea, put them in a container, add 10 mL deionized water, stir and mix evenly, transfer the mixture to a hydrothermal reactor and seal it, react at 130 °C for 3 h, after the reaction is completed, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol, dry it at 80 °C for 6 h to obtain the precursor powder; (2) The precursor powder obtained above was placed in a muffle furnace and heated to 300°C at a heating rate of 10°C / min under an air atmosphere and calcined for 3h. After calcination, the obtained powder was transferred to a tube reduction furnace and heated to 550°C at a heating rate of 10°C / min under a hydrogen atmosphere and reduced for 6h to obtain catalyst D3. (3) Add 100 mg naphthalene, 25 mg catalyst D3 and 30 mL n-hexane to a high-pressure reactor, seal it and fill it with 2.5 MPa of hydrogen gas. React at 150 °C for 2 h to obtain product M3.

[0042] Comparative Example 4; (1) Weigh 20 mmol nickel chloride hexahydrate, 5 mmol cerium nitrate hexahydrate, and 5 mmol aluminum nitrate nonahydrate, and dissolve them together in 40 mL of deionized water, which is denoted as solution A. Dissolve 2.12 g sodium carbonate in 40 mL of deionized water, which is denoted as solution B. Under vigorous stirring, slowly add solution A to solution B, controlling the dropping rate to about 1 mL / min. Stir and age the mixed slurry at 80 °C for 12 h to allow it to fully precipitate and crystallize. After the reaction is complete, centrifuge the product, wash it 3 times each with deionized water and anhydrous ethanol, and then dry it at 80 °C for 6 h to obtain the precursor powder; (2) The precursor powder obtained above was placed in a muffle furnace and heated to 300°C at a heating rate of 10°C / min under an air atmosphere and calcined for 3h. After calcination, the obtained powder was transferred to a tube reduction furnace and heated to 550°C at a heating rate of 10°C / min under a hydrogen atmosphere and reduced for 6h to obtain catalyst D4. (3) Add 100 mg naphthalene, 25 mg catalyst D4 and 30 mL n-hexane to a high-pressure reactor, seal it and purge with 2.5 MPa of hydrogen gas, and react at 150 °C for 2 h to obtain product M4.

[0043] Comparative Example 5; (1) Weigh 20 mmol nickel chloride hexahydrate, 5 mmol cerium nitrate hexahydrate, 5 mmol aluminum nitrate nonahydrate and 4.2 g urea, put them in a container, add 10 mL deionized water, stir and mix evenly, transfer the mixture to a hydrothermal reactor and seal it, react at 130 °C for 3 h, after the reaction is completed, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol, dry it at 80 °C for 6 h to obtain the precursor powder; (2) The precursor powder obtained above was placed in a muffle furnace and heated to 300°C at a heating rate of 10°C / min under an air atmosphere and calcined for 3 hours to obtain catalyst D5. (3) Add 100 mg naphthalene, 25 mg catalyst D5 and 30 mL n-hexane to a high pressure vessel, seal it and fill it with 2.5 MPa of hydrogen gas. React at 150 °C for 2 h to obtain product M5.

[0044] Comparative Example 6; (1) Weigh 20 mmol nickel chloride hexahydrate, 5 mmol cerium nitrate hexahydrate, 5 mmol aluminum nitrate nonahydrate and 4.2 g urea, put them in a container, add 10 mL deionized water, stir and mix evenly, transfer the mixture to a hydrothermal reactor and seal it, react at 130 °C for 3 h, after the reaction is completed, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol, dry it at 80 °C for 6 h to obtain the precursor powder; (2) The precursor powder obtained above was placed in a muffle furnace and heated to 300°C at a heating rate of 10°C / min under an air atmosphere and calcined for 3h. After calcination, the obtained powder was transferred to a tube reduction furnace and heated to 450°C at a heating rate of 10°C / min under a hydrogen atmosphere and reduced for 6h to obtain catalyst D6. (3) Add 100 mg naphthalene, 25 mg catalyst D6 and 30 mL n-hexane to a high-pressure reactor, seal it and purge with 2.5 MPa of hydrogen gas, and react at 150 °C for 2 h to obtain product M6.

[0045] Comparative Example 7; (1) Weigh 20 mmol nickel chloride hexahydrate, 5 mmol cerium nitrate hexahydrate, 5 mmol aluminum nitrate nonahydrate and 4.2 g urea, put them in a container, add 10 mL deionized water, stir and mix evenly, transfer the mixture to a hydrothermal reactor and seal it, react at 130 °C for 3 h, after the reaction is completed, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol, dry it at 80 °C for 6 h to obtain the precursor powder; (2) The precursor powder obtained above was placed in a muffle furnace and heated to 300°C at a heating rate of 10°C / min under an air atmosphere and calcined for 3h. After calcination, the obtained powder was transferred to a tube reduction furnace and heated to 650°C at a heating rate of 10°C / min under a hydrogen atmosphere and reduced for 6h to obtain catalyst D7. (3) Add 100 mg naphthalene, 25 mg catalyst D7 and 30 mL n-hexane to a high pressure vessel, seal it and fill it with 2.5 MPa of hydrogen gas. React at 150 °C for 2 h to obtain product M7.

[0046] Comparative Example 8: 100 mg naphthalene, 25 mg commercial Ni-Mo / Al2O3 catalyst (NiO 3 wt%, MoO3 15 wt%) and 30 mL n-hexane were added to a high-pressure reactor, sealed, and purged with 2.5 MPa of hydrogen gas. The reaction was carried out at 150 °C for 2 h to obtain product M8.

[0047] Comparative Example 9: 100 mg of high-temperature coal tar, 25 mg of commercial Ni-Mo / Al2O3 catalyst (NiO 3 wt%, MoO3 15 wt%) and 30 mL of n-hexane were added to a high-pressure reactor, sealed, and charged with 2.5 MPa of hydrogen gas. The reaction was carried out at 280 °C for 4 h to obtain product M9.

[0048] The reaction solutions of the products of each embodiment and comparative example were quantitatively analyzed by gas chromatography. By analyzing the chromatographic peak area of ​​each component (naphthalene, tetrahydronaphthalene, cis-decahydronaphthalene, trans-decahydronaphthalene), the molar amount of each component in the reaction solution was calculated. The conversion rate = initial molar amount of naphthalene - final molar amount of naphthalene / initial molar amount of naphthalene × 100%. The specific results are shown in Table 1.

[0049] Table 1

[0050] Examples 1-3 show that when the molar ratio of Ce / Al is (0.5-2):1, the catalyst achieves complete conversion of naphthalene while obtaining a total selectivity of over 96% for decahydronaphthalene, and tetrahydronaphthalene as an intermediate product is almost completely converted. This proves that the optimal metal-support synergistic structure is formed at this ratio, which can efficiently promote the reaction to deep hydrogenation.

[0051] Comparative Example 1 demonstrates that the introduction of cerium is key to achieving deep hydrogenation. Although the catalyst lacking Ce can achieve complete conversion of naphthalene, the product is mainly tetrahydronaphthalene, and the total selectivity of decahydronaphthalene is less than 25%, indicating that it cannot effectively catalyze the second-step hydrogenation.

[0052] Comparative Examples 2 and 3 show that when the molar ratio of Ce / Al is unbalanced, the activity of the catalyst and the selectivity for deep hydrogenation both decrease significantly.

[0053] Comparative Example 4 shows that when the coprecipitation method replaces the hydrothermal method for preparing catalysts, even with the exact same formulation, a large amount of tetrahydronaphthalene intermediate still accumulates, and the catalyst activity and deep hydrogenation selectivity remain low.

[0054] Comparative Example 5 demonstrates that the hydrogen reduction step is indispensable for the generation of active nickel metal centers; the unreduced catalyst essentially loses its hydrogenation activity.

[0055] Comparative Examples 6 and 7 show that the reduction temperature is an important parameter affecting the hydrogenation selectivity of the catalyst. If it is too low, the active center will not be fully reduced, and if it is too high, the active center will easily sinter.

[0056] Comparative Example 8 shows that the catalyst of the present invention has significantly better conversion and selectivity than conventional industrial catalysts under the same mild conditions.

[0057] Using the catalyst prepared in Example 2, hydrogenation of raw high-temperature coal tar was carried out under conditions of 2.5 MPa H2 and 260–280 °C. The reaction products were analyzed by thin-layer chromatography, and the results are shown in Table 2 below: Table 2

[0058] Example 6 illustrates that the catalyst of the present invention has shown significant activation and conversion capabilities for complex components of high-temperature coal tar, achieving an aromatic hydrocarbon conversion rate of 31.6% and increasing the detectable saturated hydrocarbon content in the product from 25.9% in the feedstock to 49.3%. This demonstrates that the catalyst can effectively initiate the hydrogenation saturation process of polycyclic aromatic hydrocarbons under relatively mild conditions.

[0059] Example 7 illustrates that at the optimized reaction temperature, the deep hydrogenation capacity of the catalyst is fully released, and its aromatic conversion rate is significantly increased to 61.1%. At the same time, the detectable saturated hydrocarbon content is significantly increased to 71.2%. Almost all the aromatics converted in the feedstock are converted into cycloalkanes through the deep hydrogenation saturation pathway, rather than undergoing side reactions such as cracking.

[0060] Comparative Example 9 illustrates that using a commercially available Ni-Mo / Al2O3 catalyst without pre-sulfurization, under the same mild conditions (280°C, 2.5 MPa H2), it is difficult to effectively activate hydrogen and catalyze aromatic saturation when treating high-temperature coal tar.

[0061] like Figure 1 As shown, Figure 1 (a) and Figure 1 (b) is a TEM image of catalyst E2 prepared in Example 2 of the present invention; Figure 1 (c) is an HRTEM image of catalyst E2 prepared in Example 2 of the present invention; Figure 1 (d) is an image showing the lattice spacing of Ni(111) and NiO(111) in the catalyst E2 prepared in Example 2 of this invention. Figure 1 (c) It can be seen that the average particle size of the active component Ni is 5.47 nm.

[0062] like Figure 2 As shown, Figure 2 (a) shows the XRD patterns of the catalysts prepared in Example 2 and Comparative Examples 1-3 of the present invention, wherein NiAl-1 is the XRD pattern of the catalyst in Comparative Example 1, NiCeAl-2 is the XRD pattern of the catalyst in Comparative Example 3, NiCeAl-3 is the XRD pattern of the catalyst in Example 2, and NiCeAl-4 is the XRD pattern of the catalyst in Comparative Example 2. Figure 2 (b) shows the XRD patterns of the catalyst precursors of Example 2 and Comparative Example 1, where NiCeAl-3-LDH is the XRD pattern of the catalyst precursor of Example 2, and NiAl-LDH is the XRD pattern of the catalyst precursor of Comparative Example 1. Figure 2 (b) It is known that the catalyst precursor of Example 2 is a two-phase mixture formed by NiAl hydrotalcite and basic cerium carbonate, and the active component Ni is highly dispersed.

[0063] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A low-temperature aromatic hydrocarbon-saturated non-precious metal catalyst, characterized in that, The catalyst Ni / CeAlO x Using cerium-aluminum composite oxide as a support and metallic nickel as the active component, the catalyst has an average particle size of 5-6 nm and a specific surface area of ​​170-190 m². 2 / g, surface acidity is 150~165umol / g, Ce in the carrier 3+ The percentage is 0.18~0.

25.

2. A method for preparing the catalyst as described in claim 1, characterized in that, Includes the following steps: (1) Dissolve nickel salt, cerium salt, aluminum salt and urea in deionized water, mix evenly, carry out hydrothermal reaction, and after the reaction, separate solid and liquid, wash and dry to obtain the precursor; (2) The above precursor was calcined at 200~600℃ and then reduced in a hydrogen atmosphere to obtain the catalyst Ni / CeAlO. x .

3. The preparation method according to claim 2, characterized in that, In step (1), the amounts of nickel salt, cerium salt and aluminum salt satisfy the following molar ratio: Ni:(Ce+Al)=(1.5~3):

1.

4. The preparation method according to claim 2, characterized in that, In step (1), the amounts of cerium salt and aluminum salt satisfy the following molar ratio: Ce:Al = (0.1~1.8):0.

9.

5. The preparation method according to claim 2, characterized in that, In step (1), the molar ratio of urea to total metal ions (Ni+Ce+Al) is (2~4):

1.

6. The preparation method according to claim 2, characterized in that, The amount of deionized water added in step (1) makes the concentration of total metal ions (Ni+Ce+Al) in the reaction system 2.5~3.5mol / L.

7. The preparation method according to claim 2, characterized in that, The reduction temperature in step (2) is 500~600℃.

8. The application of the catalyst according to claim 1, characterized in that, The catalyst can be used for catalytic hydrogenation reactions of naphthalene and high-temperature coal tar.

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