A hydrogenation catalyst and its preparation method and application

Abstract

The present invention belongs to the field of catalyst technology, and specifically relates to a hydrogenation catalyst and a preparation method and application thereof; the preparation method comprises the following steps: S1: spraying a potassium ruthenate solution on a carrier under stirring, drying, and obtaining a catalyst intermediate; the carrier comprises activated carbon; the mass ratio of the potassium ruthenate solution to the carrier is 0.4-0.8:1; the spraying rate is 100-600 mL / min; the potassium ruthenate solution contains 1wt%-4wt% ruthenium; S2: loading rare earth nitrate onto the catalyst intermediate, aging, and drying to obtain the hydrogenation catalyst. The prepared hydrogenation catalyst is an eggshell-type catalyst, with highly dispersed ruthenium as an active metal loaded on the surface of the carrier, and also loaded with rare earth oxides, with high utilization rate of active metals, high catalytic efficiency of catalyst hydrogenation reaction, good long-term stability, and high reaction controllability.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and specifically relates to a hydrogenation catalyst and a preparation method and application thereof. Background Art

[0002] One of the major ways to obtain cyclohexane and cyclohexene is to use the benzene hydrogenation process for preparation. The active metals used in the benzene hydrogenation process are usually platinum, ruthenium, cobalt, nickel, etc. Cobalt and nickel are generally low in activity as active metals, and although the precious metals platinum and ruthenium have good activity, they are expensive and the catalyst has a low cost performance ratio. The existing benzene hydrogenation process is generally carried out at low temperature and low pressure, and a supported catalyst (such as an alumina supported catalyst) and a fixed bed process are often used. The reaction carried out in the benzene hydrogenation process is a solid-liquid-gas three-phase reaction. When the carrier pore size is too small, or the active component is not on the carrier surface but in the inner pore, it will lead to a low utilization rate of the active metal and a reduced catalyst cost performance ratio. Moreover, when the product of the hydrogenation reaction stays in the inner pore of the carrier for too long and cannot be quickly desorbed, there will be a situation where cyclohexene is prepared but cyclohexane is finally obtained, and the reaction is difficult to control. Summary of the invention

[0003] Therefore, the present invention provides a hydrogenation catalyst and a preparation method and application thereof, using activated carbon as a carrier, and controlling the spraying rate, the mass ratio of potassium ruthenate solution to the carrier, and the concentration of the potassium ruthenate solution so that the active metal ruthenium is evenly dispersed on the surface of the carrier, and rare earth oxides are loaded on the outer layer, so that the prepared hydrogenation catalyst has a high active metal utilization rate and a certain anti-scouring ability, and can be used in a fluidized bed.

[0004] To this end, the present invention provides the following technical solutions.

[0005] The present invention provides a method for preparing a hydrogenation catalyst, comprising the following steps: S1: spraying a potassium ruthenate solution onto a carrier under stirring, drying, and obtaining a catalyst intermediate; the carrier comprises activated carbon; the mass ratio of the potassium ruthenate solution to the carrier is 0.4-0.8:1; the spraying rate is 100-600 mL / min; the potassium ruthenate solution contains 1wt%-4wt% of ruthenium; S2: loading a rare earth nitrate onto the catalyst intermediate, aging, and drying to obtain the hydrogenation catalyst.

[0006] Optionally, in S1, the stirring rate is 30 to 50 rpm.

[0007] Optionally, the drying temperature is 90-150° C. and the drying time is 1-10 hours.

[0008] Optionally, after spraying the potassium ruthenate solution and before drying, a step of standing is also included; optionally, the standing time is 1 to 5 hours.

[0009] Optionally, in S1, the method for preparing the potassium ruthenate solution includes: mixing ruthenium element and potassium hydroxide, and calcining them in an oxygen-containing atmosphere to obtain a ruthenium precursor; and adding water to the ruthenium precursor to obtain the potassium ruthenate solution.

[0010] Optionally, the mass ratio of the ruthenium element to the base is 1:2-10.

[0011] Optionally, the calcination temperature is 400-800° C. and the calcination time is 2-10 hours.

[0012] Optionally, air is introduced so that the roasting is carried out in an oxygen-containing atmosphere; optionally, the flow rate of the introduced air is 80 to 150 mL / min.

[0013] Optionally, in S2, the method of loading the rare earth nitrate onto the catalyst intermediate includes any one of spraying and impregnation.

[0014] Optionally, in S2, the mass of the rare earth nitrate is 1% to 10% of the carrier.

[0015] Optionally, in S2, the aging time is 1 to 20 hours; the aging can be carried out at room temperature.

[0016] Optionally, in S2, the drying temperature is 90-130° C. and the drying time is 2-6 hours.

[0017] Optionally, the spraying step includes: spraying a rare earth nitrate solution onto the catalyst intermediate under stirring; optionally, the volume ratio of the rare earth nitrate solution to the catalyst intermediate is 0.3 to 0.8:1; optionally, the spraying rate is 100 to 600 mL / min; optionally, the stirring rate is 30 to 50 rpm; or, the impregnation step includes: mixing the catalyst intermediate with a rare earth nitrate solution, and impregnating; optionally, the volume ratio of the rare earth nitrate solution to the catalyst intermediate is 1:0.9 to 1.1.

[0018] Optionally, the size of the activated carbon is 16 to 100 meshes; optionally, the activated carbon includes at least one of spherical activated carbon, columnar activated carbon, and granular activated carbon.

[0019] Optionally, the rare earth nitrate includes at least one of cerium nitrate, lanthanum nitrate and samarium nitrate.

[0020] The present invention provides a hydrogenation catalyst prepared by the above preparation method.

[0021] Optionally, the bulk density of the hydrogenation catalyst is 0.4 to 0.7 g / mL.

[0022] Optionally, the particle size of ruthenium distributed on the hydrogenation catalyst is 1 to 2 nm.

[0023] The present invention provides application of the above hydrogenation catalyst in a benzene hydrogenation process; optionally, the equipment used in the benzene hydrogenation process includes a fluidized bed.

[0024] The beneficial effects of the present invention are:

[0025] The present invention provides a method for preparing a hydrogenation catalyst, comprising the following steps: S1: spraying a potassium ruthenate solution onto a carrier under stirring, drying, and obtaining a catalyst intermediate; the carrier comprises activated carbon; the mass ratio of the potassium ruthenate solution to the carrier is 0.4-0.8:1; the spraying rate is 100-600 mL / min; the potassium ruthenate solution contains 0.1wt%-4wt% ruthenium; S2: loading rare earth nitrate onto the catalyst intermediate, aging, and drying to obtain the hydrogenation catalyst. The prepared hydrogenation catalyst is an eggshell-type catalyst, with highly dispersed ruthenium as an active metal loaded on the surface of the carrier, and also loaded with rare earth oxides, high utilization rate of active metals, high catalytic efficiency of catalyst hydrogenation reaction, good long-term stability, and high reaction controllability.

[0026] Activated carbon itself has a high specific surface area, and has groups such as hydroxyl, carboxyl and ester groups on the surface. When the hydroxyl group, as a reducing group, encounters the strong oxidizing potassium ruthenate, an in-situ reaction immediately occurs to form an active site of ruthenium. The potassium ruthenate solution is loaded on the carrier by a spraying method, and the mass ratio of the potassium ruthenate solution to the carrier is controlled. The concentration of ruthenium in the potassium ruthenate solution and the spraying rate can control the reaction rate of potassium ruthenate and the reducing groups on the surface of the activated carbon, so as to achieve a high dispersion effect of ruthenium on the surface of the carrier, and the size of the ruthenium particles generated by the in-situ reaction is between 1 and 2 nm; this method can also reduce the content of ruthenium in the pores of the carrier, which can also reduce the probability of hydrogenation reaction in the pores during use, and increase the probability of hydrogenation reaction on the catalyst surface during use, so that the controllability of the reaction is increased; and there are few reactive active sites in the pores, so that a large number of reactants will not be blocked in the pores, and the residence time of the reactants in the pores can be reduced, which can reduce the situation where the reactants over-react to form cyclohexane when preparing cyclohexene. In addition, activated carbon itself has abundant mesopores and micropores, and has a strong adsorption effect. Impurity small molecules are easily adsorbed by activated carbon in the activated carbon system, reducing their impact on the performance of the catalyst. After the catalyst intermediate is mixed with the rare earth nitrate solution, impregnated, aged, and dried, the rare earth ions react to form rare earth oxides loaded on the catalyst surface. In addition, in the reaction between potassium ruthenate and the weak reducing groups on the surface of activated carbon, hydroxides of the corresponding metal ions are also generated. Rare earth nitrates and hydroxides react to form corresponding rare earth-containing alkaline species with a high melting point, which are evenly distributed around ruthenium, making ruthenium as an active component more stable and having better long-term activity.

[0027] In the preparation method of the hydrogenation catalyst provided by the present invention, in S1, the preparation method of the potassium ruthenate solution comprises: mixing ruthenium element and potassium hydroxide, and calcining in an oxygen-containing atmosphere to obtain a ruthenium precursor; and adding water to the ruthenium precursor to obtain the potassium ruthenate solution. It is preferred to use ruthenium element and potassium hydroxide to prepare the potassium ruthenate solution, because commercially available potassium ruthenate is expensive and not suitable for large-scale industrial use.

[0028] The bulk density of the hydrogenation catalyst provided by the present invention is 0.4-0.7 g / mL, which makes the hydrogenation catalyst convenient to use in a fluidized bed and can realize free flow in a fluidized state. If the bulk density is too low, the hydrogenation catalyst will float on the surface, and if the bulk density is too high, it will sink to the bottom, which is not conducive to sufficient contact between the catalyst and the material. DETAILED DESCRIPTION

[0029] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0030] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0031] Experimental drugs:

[0032] Spherical activated carbon: Baiyang Chemical Technology Co., Ltd., batch 202404, pore volume ≥ 0.7 cm 3 / g, pore size>5nm.

[0033] Example 1

[0034] This embodiment provides a hydrogenation catalyst and a preparation method thereof, comprising the following steps:

[0035] (1) Ruthenium powder and potassium hydroxide are mixed in a mass ratio of 1:4, air is introduced at a flow rate of 100 mL / min, and calcined at 400° C. for 2 h to obtain a ruthenium precursor, and water is added to the obtained ruthenium precursor until the obtained potassium ruthenate solution contains 1.5 wt % of ruthenium.

[0036] (2) Take spherical activated carbon and spray potassium ruthenate solution therein at a rotation speed of 30 rpm, the mass ratio of potassium ruthenate solution to spherical activated carbon is 0.6:1, and the spraying rate is 300 mL / min; after the spraying is completed, let it stand for 1 hour to allow the potassium ruthenate solution to be completely reacted and absorbed, and dry it at 120° C. for 4 hours to obtain a catalyst intermediate.

[0037] (3) Take 1% lanthanum nitrate by weight of the spherical activated carbon, add water to prepare a lanthanum nitrate solution with a volume ratio of 1:1 to the catalyst intermediate, immerse the catalyst intermediate in the lanthanum nitrate solution, age it at room temperature for 1 hour, and dry it at 120° C. for 4 hours to obtain a hydrogenation catalyst.

[0038] Take the prepared hydrogenation catalyst, weigh its mass and volume, and calculate the bulk density to be 0.56 g / mL. After reducing it, the average particle size of the ruthenium particles thereon is 1.8 nm as measured by transmission electron microscopy. The reduction conditions are: put the hydrogenation catalyst into a reactor, introduce hydrogen into the reactor so that the catalyst contacts the hydrogen for reduction reaction, the reduction reaction temperature is 450°C, the time is 20 hours, the hydrogen pressure is 0.5 MPa, and after the reduction is completed, it is cooled to room temperature for sample preparation and testing. The following bulk density and particle size test methods are the same as here.

[0039] Example 2

[0040] This embodiment provides a hydrogenation catalyst and a preparation method thereof, which is different from the embodiment 1 only in that the mass ratio of ruthenium powder to potassium hydroxide in step (1) is 1:6. The bulk density of the hydrogenation catalyst obtained is 0.60 g / mL, and the average particle size of the ruthenium particles thereon is 1.4 nm.

[0041] Example 3

[0042] This embodiment provides a hydrogenation catalyst and a preparation method thereof, which is different from the embodiment 1 only in that the mass ratio of ruthenium powder to potassium hydroxide in step (1) is 1:10. The bulk density of the hydrogenation catalyst obtained is 0.62 g / mL, and the average particle size of the ruthenium particles thereon is 1.2 nm.

[0043] Example 4

[0044] This embodiment provides a hydrogenation catalyst and a preparation method thereof, which is different from the embodiment 1 only in that the calcination is performed at 600° C. The bulk density of the hydrogenation catalyst obtained is 0.56 g / mL, and the average particle size of the ruthenium particles thereon is 1.6 nm.

[0045] Example 5

[0046] This embodiment provides a hydrogenation catalyst and a preparation method thereof, which is different from the embodiment 1 only in that in step (3), the aging time is 20 hours. The bulk density of the hydrogenation catalyst obtained is 0.56 g / mL, and the average particle size of the ruthenium particles thereon is 1.8 nm.

[0047] Example 6

[0048] This embodiment provides a hydrogenation catalyst and a preparation method thereof, comprising the following steps:

[0049] (1) Ruthenium powder and potassium hydroxide are mixed in a mass ratio of 1:2, air is introduced at a flow rate of 80 mL / min, and calcined at 400° C. for 10 h to obtain a ruthenium precursor. Water is added to the obtained ruthenium precursor until the obtained potassium ruthenate solution contains 1 wt % of ruthenium.

[0050] (2) Take spherical activated carbon and spray potassium ruthenate solution therein at a rotation speed of 30 rpm, the mass ratio of potassium ruthenate solution to spherical activated carbon is 0.8:1, and the spraying rate is 600 mL / min; after the spraying is completed, let it stand for 5 hours to allow the potassium ruthenate solution to be completely reacted and absorbed, and dry it at 90° C. for 10 hours to obtain a catalyst intermediate.

[0051] (3) Take cerium nitrate that is 10% of the mass of the spherical activated carbon, add water to prepare a cerium nitrate solution with a volume ratio of 0.4:1 to the catalyst intermediate, stir the catalyst intermediate at a speed of 50 rpm, and spray the cerium nitrate solution thereon at a rate of 100 mL / min. After the spraying is completed, age at room temperature for 10 h and dry at 90° C. for 6 h to obtain a hydrogenation catalyst.

[0052] The bulk density of the hydrogenation catalyst obtained was 0.56 g / mL, and the average particle size of the ruthenium particles thereon was 1.8 nm.

[0053] Example 7

[0054] This embodiment provides a hydrogenation catalyst and a preparation method thereof, comprising the following steps:

[0055] (1) Ruthenium powder and potassium hydroxide are mixed in a mass ratio of 1:10, air is introduced at a flow rate of 150 mL / min, and calcined at 800° C. for 2 h to obtain a ruthenium precursor. Water is added to the obtained ruthenium precursor until the obtained potassium ruthenate solution contains 2 wt % of ruthenium.

[0056] (2) Take spherical activated carbon and spray potassium ruthenate solution therein at a rotation speed of 50 rpm, the mass ratio of potassium ruthenate solution to spherical activated carbon is 0.4:1, and the spraying rate is 100 mL / min; after the spraying is completed, let it stand for 3 hours to allow the potassium ruthenate solution to be completely reacted and absorbed, and dry it at 150° C. for 1 hour to obtain a catalyst intermediate.

[0057] (3) Take 5% samarium nitrate by mass of spherical activated carbon, add water to prepare a samarium nitrate solution with a volume ratio of 0.7:1 to the catalyst intermediate, stir the catalyst intermediate at a speed of 30 rpm, and spray the samarium nitrate solution at a rate of 600 mL / min. After spraying, age at room temperature for 10 h and dry at 130° C. for 2 h to obtain a hydrogenation catalyst.

[0058] The bulk density of the hydrogenation catalyst obtained was 0.62 g / mL, and the average particle size of the ruthenium particles thereon was 1.6 nm.

[0059] Comparative Example 1

[0060] This comparative example provides a hydrogenation catalyst and a preparation method thereof, which differs from Example 1 only in that, in step (2), the mass ratio of potassium ruthenate solution to spherical activated carbon is 0.3:1. The bulk density of the hydrogenation catalyst obtained is 0.56 g / mL, and the average particle size of the ruthenium particles thereon is 2.7 nm.

[0061] Comparative Example 2

[0062] This comparative example provides a hydrogenation catalyst and a preparation method thereof, which differs from Example 1 only in that, in step (2), the mass ratio of potassium ruthenate solution to spherical activated carbon is 0.9:1. The bulk density of the hydrogenation catalyst obtained is 0.55 g / mL, and the average particle size of the ruthenium particles thereon is 1.9 nm.

[0063] Comparative Example 3

[0064] This comparative example provides a hydrogenation catalyst and a preparation method thereof, which differs from Example 1 only in that in step (2), the spraying rate is 700 mL / min. The bulk density of the hydrogenation catalyst obtained is 0.56 g / mL, and the average particle size of the ruthenium particles thereon is 2.1 nm.

[0065] Comparative Example 4

[0066] This comparative example provides a hydrogenation catalyst and a preparation method thereof, which differs from Example 1 only in that in step (2), the spraying rate is 50 mL / min. The bulk density of the hydrogenation catalyst obtained is 0.56 g / mL, and the average particle size of the ruthenium particles thereon is 2.0 nm.

[0067] Comparative Example 5

[0068] This comparative example provides a hydrogenation catalyst and a preparation method thereof, which differs from Example 1 only in that, in step (1), water is added to the obtained ruthenium precursor until the obtained potassium ruthenate solution contains 4.3 wt % ruthenium. The obtained hydrogenation catalyst has a bulk density of 0.56 g / mL and an average particle size of ruthenium particles thereon is 2.4 nm.

[0069] Comparative Example 6

[0070] This comparative example provides a hydrogenation catalyst and a preparation method thereof, which differs from Example 1 only in that, in step (1), water is added to the obtained ruthenium precursor until the obtained potassium ruthenate solution contains 0.9 wt % ruthenium. The obtained hydrogenation catalyst has a bulk density of 0.56 g / mL and an average particle size of ruthenium particles thereon is 1.6 nm.

[0071] Comparative Example 7

[0072] This comparative example provides a hydrogenation catalyst and a preparation method thereof, which differs from Example 1 only in that step (2) is to immerse the spherical activated carbon in a potassium ruthenate solution, the mass ratio of the potassium ruthenate solution to the spherical activated carbon being 0.6:1, immerse for 2 hours, and dry at 120° C. for 4 hours to obtain a catalyst intermediate. The bulk density of the obtained hydrogenation catalyst is 0.56 g / mL, and the average particle size of the ruthenium particles thereon is 1.8 nm.

[0073] Comparative Example 8

[0074] This comparative example provides a hydrogenation catalyst and a preparation method thereof, which differs from Example 1 only in that, in step (1), an equal amount of sodium hydroxide is used instead of potassium hydroxide. The bulk density of the hydrogenation catalyst obtained is 0.56 g / mL, and the average particle size of the ruthenium particles thereon is 3.0 nm.

[0075] Test Example 1

[0076] Take 1g of each hydrogenation catalyst prepared in the embodiment and the comparative example, and put them into a reactor respectively. The reactor can simulate a fluidized bed environment. Hydrogen is introduced into the reactor to contact the catalyst with hydrogen for a reduction reaction. The temperature of the reduction reaction is 450°C, the time is 20h, and the hydrogen pressure is 0.5MPa. After the catalyst is reduced, 400mL of thiophene-free benzene is added thereto through a high-pressure tank. At 140°C and 5.0MPa hydrogen pressure, timed sampling is started, and the oil phase components are analyzed by gas chromatography to calculate the efficiency of benzene conversion to cyclohexene. The results are shown in Table 1. It can be seen that the benzene conversion efficiency of the hydrogenation catalyst prepared in the embodiment is higher than that of the hydrogenation catalyst prepared in the comparative example. The benzene conversion efficiency of the hydrogenation catalyst prepared by the preparation method of the present invention in a fluidized bed environment can be 220g / h·g cat Above, and can be as high as 312g / h·g cat .

[0077] Table 1

[0078]

[0079]

[0080] Test Example 2

[0081] Take 1g of the hydrogenation catalyst prepared in Example 1, put it into a reactor, pass hydrogen into the reactor to contact the catalyst with hydrogen for reduction reaction, the temperature of the reduction reaction is 450°C, the time is 20h, and the hydrogen pressure is 0.5MPa. After the catalyst is reduced, 300mL of thiophene-free benzene is added thereto through a high-pressure tank, and at 140°C and 5.0MPa hydrogen pressure, start timing sampling, analyze the oil phase components by gas chromatography, calculate the benzene conversion efficiency, and test once every 24 hours. The results are shown in Table 2. It can be seen that in the long-term test, the conversion efficiency of the hydrogenation catalyst prepared in Example 1 of the present invention did not decrease significantly, and it has long-term stability.

[0082] Table 2

[0083]

[0084]

[0085] Test Example 3

[0086] Take 1g of the hydrogenation catalysts prepared in the embodiment and the comparative example, respectively, and put them into a reactor, and introduce hydrogen into the reactor to contact the catalyst with hydrogen for reduction reaction. The temperature of the reduction reaction is 450°C, the time is 20h, and the hydrogen pressure is 0.5MPa. After the catalyst is reduced, 300mL of thiophene-free benzene is added thereto through a high-pressure tank, and at 140°C and 5.0MPa hydrogen pressure, the timing sampling is started, and the oil phase components are analyzed by gas chromatography to calculate the selectivity of benzene to cyclohexene. The results are shown in Table 3. It can be seen from Table 3 that the hydrogenation catalyst obtained in the embodiment of the present invention has a selectivity of benzene to cyclohexene of more than 85%, and can even be as high as 98%. The hydrogenation catalysts prepared in the comparative example have a selectivity of benzene to cyclohexene of less than 80%. The hydrogenation catalyst prepared by the preparation method provided in the present invention has a good selectivity for converting cyclohexene.

[0087] Table 3

[0088]

[0089]

[0090] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the protection scope of the invention.

Claims

1. A method for preparing a hydrogenation catalyst, characterized in that: The steps include: S1: spraying a potassium ruthenate solution onto the support under stirring, and drying to obtain a catalyst intermediate; The carrier includes activated carbon; The mass ratio of the potassium ruthenate solution to the carrier is 0.4-0.8:1; The spraying rate is 100-600 mL / min; The potassium ruthenate solution contains 1wt% to 4wt% ruthenium; S2: loading rare earth nitrate onto the catalyst intermediate, aging, and drying to obtain the hydrogenation catalyst.

2. The preparation method according to claim 1, characterized in that: In S1, the stirring rate is 30 to 50 rpm; And / or, in S1, the drying temperature is 90-150° C. and the drying time is 1-10 h; And / or, in S1, after spraying the potassium ruthenate solution and before drying, a standing step is also included; optionally, the standing time is 1 to 5 hours.

3. The preparation method according to claim 1 or 2, characterized in that: In S1, the preparation method of the potassium ruthenate solution includes: mixing ruthenium element and potassium hydroxide, and calcining them in an oxygen-containing atmosphere to obtain a ruthenium precursor; and adding water to the ruthenium precursor to obtain the potassium ruthenate solution.

4. The preparation method according to claim 3, characterized in that: The mass ratio of the ruthenium element to the base is 1:2-10; and / or, the calcination temperature is 400 to 800° C. and the calcination time is 2 to 10 hours; And / or, air is introduced so that the roasting is carried out in an oxygen-containing atmosphere; optionally, the flow rate of the introduced air is 80 to 150 mL / min.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In S2, the method of loading the rare earth nitrate onto the catalyst intermediate includes any one of spraying and impregnation; And / or, in S2, the mass of the rare earth nitrate is 1% to 10% of the carrier; And / or, in S2, the aging time is 1 to 20 hours; And / or, in S2, the drying temperature is 90-130° C. and the drying time is 2-6 hours.

6. The preparation method according to claim 5, characterized in that: The spraying step comprises: spraying a rare earth nitrate solution onto the catalyst intermediate under stirring; optionally, the volume ratio of the rare earth nitrate solution to the catalyst intermediate is 0.3-0.8:1; optionally, the spraying rate is 100-600 mL / min; optionally, the stirring rate is 30-50 rpm; Alternatively, the impregnation step comprises: mixing the catalyst intermediate with a rare earth nitrate solution, and impregnating; optionally, the volume ratio of the rare earth nitrate solution to the catalyst intermediate is 1:0.9-1.

1.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The size of the activated carbon is 16-100 mesh; optionally, the activated carbon includes at least one of spherical activated carbon, columnar activated carbon, and granular activated carbon; And / or, the rare earth nitrate includes at least one of cerium nitrate, lanthanum nitrate and samarium nitrate.

8. A hydrogenation catalyst obtained by the preparation method according to any one of claims 1 to 7.

9. The hydrogenation catalyst according to claim 8, characterized in that The bulk density of the hydrogenation catalyst is 0.4 to 0.7 g / mL; And / or, the average particle size of ruthenium particles distributed on the hydrogenation catalyst is 1 to 2 nm.

10. Use of the hydrogenation catalyst according to claim 8 or 9 in a benzene hydrogenation process; optionally, the equipment used in the benzene hydrogenation process includes a fluidized bed.

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