Nickel-based catalyst as well as preparation method and application thereof

Abstract

The invention relates to the related technical field of pyrolysis gasoline first-stage selective hydrogenation catalysts, and particularly discloses a nickel-based catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: S1, dissolving an aluminum (III) salt and a gallium (III) salt in a first solvent, adding a thickening agent, and uniformly mixing; then, sequentially carrying out aging, drying and first roasting in a protective atmosphere, so as to obtain an Al2O3-Ga2O3 carrier; step S2, dissolving a nickel (II) salt in a second solvent, and then adding the Al2O3-Ga2O3 carrier obtained in the step S1; and then, sequentially carrying out ultrasonic treatment, evaporating the second solvent to dryness, and carrying out secondary roasting in a protective atmosphere, so as to obtain the nickel-based catalyst. The nickel-based catalyst is prepared by the preparation method. The nickel-based catalyst is applied to first-stage selective hydrogenation of pyrolysis gasoline. The hydrogenation activity and selectivity of the nickel-based catalyst in first-stage selective hydrogenation of pyrolysis gasoline are greatly improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field related to a catalyst for the selective hydrogenation of pyrolysis gasoline, and specifically discloses a nickel-based catalyst and a preparation method and application thereof. Background Art

[0002] Pyrolysis gasoline is a byproduct of steam cracking ethylene production, and its output accounts for about (50-80)% of the ethylene output. As steam cracking ethylene production plants become increasingly large-scale, the output of pyrolysis gasoline also increases. How to use pyrolysis gasoline has attracted more and more attention. Pyrolysis gasoline is rich in a large number of unsaturated hydrocarbons and non-hydrocarbon compounds such as sulfur, nitrogen, and oxygen. It has extremely poor stability, especially during storage, dienes are easily polymerized to form low-polymerization polymers (green oil), and cannot be used directly as a raw material.

[0003] In industry, a two-stage hydrogenation process is generally used to refine cracking gasoline. The main purpose of the first-stage hydrogenation is to selectively hydrogenate conjugated dienes and alkenyl aromatics into monoolefins and alkyl aromatics; the main purpose of the second-stage hydrogenation is to remove monoolefins and sulfur, nitrogen, and oxygen compounds.

[0004] Among them, the primary hydrogenation catalysts for pyrolysis gasoline are mainly palladium-based catalysts and nickel-based catalysts. Although palladium-based catalysts have high activity, the price of palladium has continued to rise in recent years, and the cracking raw materials have tended to be inferior, making palladium-based catalysts prone to poisoning and deactivation. Nickel-based catalysts have the advantages of low cost, good resistance to toxicity and good stability. However, nickel-based catalysts have low hydrogenation activity and selectivity. Summary of the invention

[0005] In view of this, the present disclosure provides a nickel-based catalyst and a preparation method and use thereof, which greatly improves the hydrogenation activity and selectivity of the nickel-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline.

[0006] In a first aspect, the present disclosure provides a method for preparing a nickel-based catalyst, the preparation method comprising the following steps:

[0007] Step S1, first dissolving aluminum (III) salt and gallium (III) salt in a first solvent, then adding a thickener and mixing evenly; then, aging, drying, and first calcining in a protective atmosphere (such as a nitrogen atmosphere or an argon atmosphere) in sequence to obtain an Al2O3-Ga2O3 carrier;

[0008] Step S2, first dissolving the nickel (II) salt in the second solvent, and then adding the Al2O3-Ga2O3 carrier obtained in step S1; then, subjecting to ultrasound, evaporating the second solvent, and second calcination in a protective atmosphere (such as a nitrogen atmosphere or an argon atmosphere, etc.) in sequence to obtain the nickel-based catalyst.

[0009] In some optional embodiments, in step S1, the molar ratio of aluminum (III) ions in the aluminum (III) salt to gallium (III) ions in the gallium (III) salt is 1:(0.1-0.3); for example, 1:0.1, 1:0.11, 1:0.12, 1:0.13, 1:0.14, 1:0.15, 1:0.16, 1:0.17, 1:0.18, 1:0.19, 1:0.2, 1:0.21, 1:0.22, 1:0.23, 1:0.24, 1:0.25, 1:0.26, 1:0.27, 1:0.28, 1:0.29 or 1:0.3, etc. In other optional embodiments, in step S1, the molar ratio of aluminum (III) ions in the aluminum (III) salt to gallium (III) ions in the gallium (III) salt is 1:(0.15-0.25). In some specific embodiments, in step S1, the molar ratio of aluminum (III) ions in the aluminum (III) salt to gallium (III) ions in the gallium (III) salt is 1:0.2.

[0010] In some optional embodiments, in step S1, the aluminum (III) salt is selected from at least one of Al (NO3) 3, AlCl3 and Al2 (SO4) 3. In some specific embodiments, in step S1, the aluminum (III) salt is selected from Al (NO3) 3.

[0011] In some optional embodiments, in step S1, the gallium (III) salt is selected from at least one of Ga (NO 3 ) 3 , GaCl 3 and Ga 2 (SO 4 ) 3 . In some specific embodiments, the gallium (III) salt is selected from Ga (NO 3 ) 3 .

[0012] In some optional embodiments, in step S1, the first solvent is selected from at least one of water, methanol and ethanol. In some specific embodiments, the first solvent is selected from ethanol; for example, industrial alcohol.

[0013] In some optional embodiments, in step S1, the thickener is selected from a triblock copolymer of polyethylene oxide-polypropylene oxide-polyethylene oxide with a molecular weight of 3000 to 10000, such as 3000, 3500, 4000, 4500, 5000, 5500, 5600, 5700, 5800, 5900, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500 or 10000, etc. In some specific embodiments, in step S1, the thickener is selected from a triblock copolymer of ethylene oxide-polypropylene oxide-polyethylene oxide with a molecular weight of 5800, such as nonionic surfactant P123.

[0014] In some optional embodiments, in step S1, the aging temperature is (20-40)°C; for example, 20°C, 25°C, 30°C, 35°C or 40°C.

[0015] In some optional embodiments, in step S1, the aging time is (1 to 10) d; for example, 1 d, 1.5 d, 2 d, 2.5 d, 3 d, 3.5 d, 4 d, 4.5 d, 5 d, 5.5 d, 6 d, 6.5 d, 7 d, 7.5 d, 8 d, 8.5 d, 9 d, 9.5 d or 10 d, etc.

[0016] In some optional embodiments, in step S1, the drying temperature is (60-100)°C; for example, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, etc.

[0017] In some optional embodiments, in step S1, the drying time is (8 to 12) h; for example, 8 h, 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, 11.5 h or 12 h, etc.

[0018] In some optional embodiments, in step S1, the procedure of the first calcination is: first, calcining at (400-500)°C (e.g., 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C or 500°C, etc.) for (1-3)h (e.g., 1h, 1.5h, 2h, 2.5h or 3h, etc.); then, calcining at (500-700)°C (e.g., 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C , 670℃, 680℃, 690℃ or 700℃, etc.) for (1-3)h (e.g., 1h, 1.5h, 2h, 2.5h or 3h, etc.); finally, calcine at (1000-1200)℃ (e.g., 1000℃, 1010℃, 1020℃, 1030℃, 1040℃, 1050℃, 51060℃, 1070℃, 1080℃, 1090℃, 1100℃, 1110℃, 1120℃, 1130℃, 1140℃, 1150℃, 1160℃, 1170℃, 1180℃, 1190℃ or 1200℃, etc.) for (1-3)h (e.g., 1h, 1.5h, 2h, 2.5h or 3h, etc.). In some specific embodiments, in step S1, the first calcination procedure is: first, calcination at 450°C for 2 hours; then, calcination at 600°C for 2 hours; finally, calcination at 1100°C for 2 hours.

[0019] In some optional embodiments, the ratio of the total molar amount of aluminum (III) ions in the aluminum (III) salt and the gallium (III) ions in the gallium (III) salt to the molar amount of nickel (II) ions in the nickel (II) salt is 1: (0.1-0.5); for example, 1:0.10, 1:0.11, 1:0.12, 1:0.13, 1:0.14, 1:0.15, 1:0.16, 1:0.17, 1:0.18, 1:0.19, 1:0.20, 1:0.21, 1:0.22, 1:0.23, 1:0.24, 1:0.25, 1:0.26, 1:0.27, 1:0.28, 1:0.29, 1:0.30, 1:0.31, 1:0.32, 1:0.33, 1:0.34, 1:0.35, 1:0.36, 1:0.37, 1:0.38, 1:0.39, 1:0.40, 1:0.41, 1:0.42, 1:0.43, 1:0.44, 1:0.45, 1:0.46, 1:0.47, 1:0.48, 1:0.49 or 1:0.50, etc. In other optional embodiments, the ratio of the total molar amount of aluminum (III) ions in the aluminum (III) salt and gallium (III) ions in the gallium (III) salt to the molar amount of nickel (II) ions in the nickel (II) salt is 1:(0.2-0.4). In some specific embodiments, the ratio of the total molar amount of aluminum (III) ions in the aluminum (III) salt and gallium (III) ions in the gallium (III) salt to the molar amount of nickel (II) ions in the nickel (II) salt is 1:0.3.

[0020] In some optional embodiments, in step S2, the second calcination procedure is: calcining at (300-400)°C (e.g., 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C or 400°C, etc.) for (1-3)h (e.g., 1h, 1.5h, 2h, 2.5h or 3h, etc.).

[0021] In some optional embodiments, in step S2, the nickel (II) salt is selected from at least one of Ni (NO3) 2, NiCl2 and NiSO4. In some specific embodiments, in step S2, the nickel (II) salt is selected from Ni (NO3) 2.

[0022] In some optional embodiments, in step S2, the second solvent is selected from at least one of water, methanol and ethanol. In some specific embodiments, in step S2, the second solvent is selected from water, such as deionized water.

[0023] In a second aspect, the present disclosure provides a nickel-based catalyst, which is prepared by the preparation method described in the first aspect.

[0024] In a third aspect, the present disclosure provides a use of the nickel-based catalyst described in the second aspect in the first-stage selective hydrogenation of pyrolysis gasoline.

[0025] The present disclosure has the following beneficial effects:

[0026] First, the present disclosure improves the hydrogenation activity and selectivity of nickel-based catalysts in the first-stage selective hydrogenation of pyrolysis gasoline.

[0027] Second, the present disclosure uses a combination of Al2O3 and Ga2O3 in an Al2O3-Ga2O3 carrier, so that the hydrogenation activity and selectivity of the nickel-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline are significantly improved. 3+ and Ga 3+ The molar ratio of Al2O3 to Ga2O3 in the Al2O3-Ga2O3 carrier significantly affects the hydrogenation activity and selectivity of the nickel-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline; specifically, with the increase of Al 3+ and Ga 3+ The molar ratio of Ni-based catalyst increases from 1:0.1 to 1:0.3, and the hydrogenation activity and selectivity of Ni-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline show a trend of "first increasing and then decreasing".

[0028] Third, the three-step calcination method in the first calcination in step S1 of the present application can significantly improve the hydrogenation activity and selectivity of the nickel-based catalyst in the one-stage selective hydrogenation of pyrolysis gasoline.

[0029] Fourth, in step S2 of this application, 3+ and Ga 3+ The total molar amount and Ni 2+ The molar ratio (equivalent to the amount of nickel loaded on the Al2O3-Ga2O3 carrier) slightly affects the hydrogenation activity and selectivity of the nickel-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline; specifically, with the increase of Al 3+ and Ga 3+ The total molar amount and Ni 2+ The molar ratio increases from 1:0.1 to 1:0.5, and the hydrogenation activity and selectivity of the nickel-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline show a trend of "first increasing and then decreasing". DETAILED DESCRIPTION

[0030] The present disclosure discloses a nickel-based catalyst and a preparation method and use thereof. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all deemed to be included in this disclosure. The methods and applications of the present disclosure have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of this disclosure to implement and apply the disclosed technology.

[0031] Unless otherwise specified, all reagents used in the present disclosure are commercially available and are of analytical grade.

[0032] Unless otherwise specified, the aluminum nitrate (chemical formula: Al(NO 3 ) 3 , CAS No.: 13473-90-0) used in the present disclosure has a molecular weight of 213.00.

[0033] Unless otherwise specified, the molecular weight of gallium nitrate (chemical formula: Ga(NO3)3, CAS No.: 13494-90-1) used in the present disclosure is 255.74.

[0034] Unless otherwise specified, the molecular weight of nickel nitrate (chemical formula: Ni(NO3)2, CAS No.: 14216-75-2) used in the present disclosure is 182.70.

[0035] In order to make the purpose, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below in conjunction with examples.

[0036] Preparation of nickel-based catalysts:

[0037] The method for preparing the nickel-based catalyst specifically comprises the following steps:

[0038] Step S1, first dissolve aluminum (III) salt and gallium (III) salt in a first solvent (specifically ethanol), then add a thickener (specifically a non-ionic surfactant P123) and mix evenly; then, sequentially undergo aging (conditions: temperature is 30°C, time is 3d), drying (conditions: temperature is 80°C, time is 10h), and first calcination in a protective atmosphere (the first calcination procedure: first, calcine at (400-500)°C for (1-3)h; then, calcine at (500-700)°C for (1-3)h; finally, calcine at (1000-1200)°C for (1-3)h) to obtain an Al2O3-Ga2O3 carrier; wherein the molar ratio of the aluminum (III) salt to the gallium (III) salt is 1:(0.1-0.3).

[0039] Step S2, first dissolving the nickel (II) salt in a second solvent (specifically deionized water), and then adding the Al2O3-Ga2O3 carrier obtained in step S1; thereafter, sequentially subjecting to ultrasound, evaporating the second solvent, and second calcination in a protective atmosphere (the procedure for the second calcination: calcining at (300-400)°C for (1-3) hours) to obtain the nickel-based catalyst.

[0040] Examples 1 to 5 and Comparative Examples 1 to 2:

[0041] The difference between Examples 1 to 5 and Comparative Examples 1 to 2 is that in step S1, Al 3+ and Ga 3+ The total molar amount of Al 3+ and Ga 3+ The molar ratio of the catalyst is different. The conditions for preparing the nickel-based catalyst in Examples 1 to 5 and Comparative Examples 1 to 2 are shown in Table 1.

[0042] Table 1 Selection of conditions for preparing nickel-based catalysts in Examples 1 to 5 and Comparative Examples 1 to 2:

[0043]

[0044]

[0045] Embodiment 6~9:

[0046] Compared with Example 3, the differences between Examples 6 to 9 are as follows: 3+ and Ga 3+ The total molar amount and Ni 2+ The molar ratios are different. The conditions for preparing the nickel-based catalysts in Examples 6 to 9 are shown in Table 2.

[0047] Table 2 Selection of conditions for preparing nickel-based catalysts in Examples 6 to 9:

[0048]

[0049]

[0050] Comparative Examples 3 to 8:

[0051] Compared with Example 3, the only difference between Comparative Examples 3 to 8 is that the first calcination procedure is different. The conditions for preparing the nickel-based catalyst in Comparative Examples 3 to 9 are shown in Table 3.

[0052] Table 3 Selection of conditions for preparing nickel-based catalysts in Comparative Examples 3 to 9:

[0053]

[0054]

[0055] Determination of the specific surface area of ​​nickel-based catalysts :

[0056] The specific surface area of ​​the nickel-based catalyst was determined by low-temperature N2 physical adsorption using an Autosorb-IQ-MP physical adsorption instrument. 2 / g.

[0057] Table 4 Test results of specific surface area of ​​nickel-based catalysts of Examples 1 to 9 and Comparative Examples 1 to 8

[0058] project <![CDATA[Specific surface area, m 2 / g]]> Example 1 123.4 Example 2 124.6 Example 3 126.1 Example 4 125.7 Example 5 125.2 Example 6 126.8 Example 7 126.3 Example 8 125.8 Example 9 125.5 Comparative Example 1 113.5 Comparative Example 2 116.9 Comparative Example 3 117.5 Comparative Example 4 118.7 Comparative Example 5 119.3 Comparative Example 6 120.5 Comparative Example 7 121.0 Comparative Example 8 119.1

[0059] It can be seen from Table 4 that the nickel-based catalyst of the present application has a large specific surface area.

[0060] Performance evaluation of nickel-based catalysts:

[0061] The performance of the catalyst was evaluated using a continuous flow fixed bed small reactor, the inner diameter of the reaction tube was 16 mm, the height was 80 cm, and the reactor was electrically heated externally. The catalyst (30 mL) and the inert SiO2 carrier (30 mL) were mixed evenly and loaded into the reaction tube, and the remaining space in the reaction tube was filled with quartz sand.

[0062] In order to simulate the process conditions of industrial pyrolysis gasoline first stage selective hydrogenation, the experimental conditions were set as follows: reaction temperature 65°C, reaction pressure 2.8MPa, liquid space velocity 4h -1 The hydrogenation activity and selectivity of the catalyst were evaluated under the condition of a volume ratio of 500:1 between H2 and pyrolysis gasoline.

[0063] The hydrogenation activity of the catalyst is represented by the diene hydrogenation conversion rate (X); the selectivity of the catalyst is represented by the diene hydrogenation selectivity (S).

[0064]

[0065] Wherein, D1 represents the diene value of pyrolysis gasoline, in g; D2 represents the diene value of hydrogenated product, in g; B1 represents the bromine value of pyrolysis gasoline, in g; B2 represents the bromine value of hydrogenated product, in g.

[0066] Among them, the diene value is used to represent the diene content in the oil, and the bromine value is used to represent the unsaturated hydrocarbon content in the oil. The diene value of the oil is measured by the maleic anhydride method, expressed as the mass of iodine consumed by 100g of the oil; the bromine value of the oil is measured by the potassium bromide method, expressed as the mass of bromine consumed by 100g of the oil.

[0067] The hydrogen used in the experiment was industrial pure; the pyrolysis gasoline used in the experiment was light yellow-green, with a diene value D1 of 12.35 g and a bromine value B1 of 60.13 g.

[0068] Table 5 Performance evaluation results of nickel-based catalysts of Examples 1 to 9 and Comparative Examples 1 to 8

[0069]

[0070]

[0071] As can be seen from Table 5, the present disclosure greatly improves the hydrogenation activity and selectivity of the nickel-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline.

[0072] By comparing Examples 1 to 5 with Comparative Examples 1 to 2, it can be seen that the present disclosure uses a combination of Al2O3 and Ga2O3 in the Al2O3-Ga2O3 carrier, so that the hydrogenation activity and selectivity of the nickel-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline are significantly improved. 3+ and Ga 3+ The molar ratio of Al2O3 to Ga2O3 in the Al2O3-Ga2O3 carrier affects the hydrogenation activity and selectivity of nickel-based catalysts in the first-stage selective hydrogenation of pyrolysis gasoline. 3+ and Ga 3+ The molar ratio of Al2O3 increases from 1:0.1 to 1:0.3, and the hydrogenation activity and selectivity of the nickel-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline show a trend of "first increasing and then decreasing". 3+ and Ga 3+ When the molar ratio of is 1:0.2, the hydrogenation activity and selectivity of the nickel-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline are optimal.

[0073] By comparing Examples 3, 6 to 9, it can be seen that Al 3+ and Ga 3+ The total molar amount and Ni 2+ The molar ratio (equivalent to the amount of nickel loaded on the Al2O3-Ga2O3 carrier) slightly affects the hydrogenation activity and selectivity of the nickel-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline; specifically, with the increase of Al 3+ and Ga 3+ The total molar amount and Ni 2+ The molar ratio ranges from 1:0.1 to 1:0.5, and the hydrogenation activity and selectivity of nickel-based catalysts in the first-stage selective hydrogenation of pyrolysis gasoline show a trend of "first increasing and then decreasing". 3+ and Ga 3+ The total molar amount and Ni 2+When the molar ratio is 1:0.3, the hydrogenation activity and selectivity of the nickel-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline are both optimal.

[0074] By comparing Example 3 with Comparative Examples 3 to 8, it can be seen that the three-step calcination method in the first calcination can significantly improve the hydrogenation activity and selectivity of the nickel-based catalyst in the first-stage selective hydrogenation of pyrolysis gasoline.

[0075] The above is a detailed introduction to a nickel-based catalyst provided by the present disclosure, its preparation method and use. This article uses specific examples to illustrate the principles and implementation methods of the present disclosure. The description of the above embodiments is only used to help understand the method and core ideas of the present disclosure. It should be pointed out that for those skilled in the art, without departing from the principles of the present disclosure, several improvements and modifications can be made to the present disclosure, and these improvements and modifications also fall within the scope of protection of the claims of the present disclosure.

Claims

1. A method for preparing a nickel-based catalyst, characterized in that: The preparation method comprises the following steps: Step S1, first dissolving aluminum (III) salt and gallium (III) salt in a first solvent, then adding a thickener and mixing evenly; then, aging, drying, and first calcining in a protective atmosphere in sequence to obtain an Al2O3-Ga2O3 carrier; Wherein, the molar ratio of aluminum (III) ions in the aluminum (III) salt to gallium (III) ions in the gallium (III) salt is 1:(0.1-0.3); The first calcination procedure is as follows: first, calcination at (400-500)°C for (1-3)h; then, calcination at (500-700)°C for (1-3)h; and finally, calcination at (1000-1200)°C for (1-3)h. Step S2, first dissolving the nickel (II) salt in a second solvent, and then adding the Al2O3-Ga2O3 carrier obtained in step S1; then, sequentially subjecting to ultrasonic treatment, evaporating the second solvent, and second calcination in a protective atmosphere to obtain the nickel-based catalyst; The ratio of the total molar amount of aluminum (III) ions in the aluminum (III) salt and gallium (III) ions in the gallium (III) salt to the molar amount of nickel (II) ions in the nickel (II) salt is 1: (0.1-0.5).

2. The preparation method according to claim 1, characterized in that: The molar ratio of the aluminum (III) ions in the aluminum (III) salt to the gallium (III) ions in the gallium (III) salt is 1:(0.05-0.15).

3. The preparation method according to claim 1 or 2, characterized in that: The first calcination procedure is: first, calcination at 450°C for 2 hours; then, calcination at 600°C for 2 hours; finally, calcination at 1100°C for 2 hours.

4. The preparation method according to claim 1, characterized in that: The aluminum (III) salt is selected from at least one of Al(NO3)3, AlCl3 and Al2(SO4)3; and / or, the gallium (III) salt is selected from at least one of Ga(NO3)3, GaCl3 and Ga2(SO4)3; And / or, the first solvent is selected from at least one of water, methanol and ethanol.

5. The preparation method according to claim 1, characterized in that: The thickener is selected from a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer with a molecular weight of 3,000 to 10,000.

6. The preparation method according to claim 1, characterized in that: The ratio of the total molar amount of aluminum (III) ions in the aluminum (III) salt and gallium (III) ions in the gallium (III) salt to the molar amount of nickel (II) ions in the nickel (II) salt is 1:1:(0.2-0.4).

7. The preparation method according to claim 1 or 6, characterized in that: The second calcination procedure is: calcination at (300-400)°C for (1-3)h.

8. The preparation method according to claim 1, characterized in that: The nickel (II) salt is selected from at least one of Ni (NO3) 2, NiCl2 and NiSO4; And / or, the second solvent is selected from at least one of water, methanol and ethanol.

9. A nickel-based catalyst, characterized in that The nickel-based catalyst is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the nickel-based catalyst according to claim 9 in the one-stage selective hydrogenation of pyrolysis gasoline.

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