Naphthalene selective hydrogenation catalyst composition and process for producing tetrahydronaphthalene by naphthalene selective hydrogenation

Abstract

The present application relates to the field of catalyst, in particular to a naphthalene selective hydrogenation catalyst composition, the catalyst composition contains a first hydrogenation catalyst and a second hydrogenation catalyst, wherein the first hydrogenation catalyst contains a first carrier and a group VIII non-noble metal supported on the first carrier; wherein the second hydrogenation catalyst contains a second carrier and a group VIII non-noble metal and a group IB metal supported on the second carrier; wherein the content of the group VIII non-noble metal in the first hydrogenation catalyst is higher than that of the second hydrogenation catalyst, preferably 1.5-5 wt%. The catalyst composition has the characteristics of high naphthalene conversion rate and high tetrahydronaphthalene selectivity.

Description

Technical Field

[0001] This invention relates to the field of catalysts, and more specifically to a naphthalene selective hydrogenation catalyst composition and a method for producing tetrahydronaphthalene by selective hydrogenation of naphthalene. Background Technology

[0002] Tetrahydronaphthalene, also known as tetrahydronaphthalene, is an important derivative of naphthalene. Tetrahydronaphthalene is miscible with almost all common solvents, making it an ideal high-boiling-point solvent capable of dissolving greases, rubber, waxes, asphalt, phenolic resins, and paints. Tetrahydronaphthalene has a wide range of applications, including the manufacture of naphthol, an intermediate in the production of the insecticide benzoyl peroxide; the production of lubricants; and its use as a degreasing agent, softener, insect repellent, and substitute for turpentine. Currently, the production of tetrahydronaphthalene in the market mainly comes from the hydrogenation of naphthalene; therefore, investigating the production of tetrahydronaphthalene through the hydrogenation of naphthalene has strong practicality and considerable economic value.

[0003] Naphthalene hydrogenation is a series of reactions: the first benzene ring undergoes hydrogenation to saturate and form tetrahydronaphthalene, and the second benzene ring undergoes further hydrogenation to saturate and form decahydronaphthalene. Currently, there is considerable research on the production of decahydronaphthalene from naphthalene hydrogenation, but less research on the production of tetrahydronaphthalene, and the selectivity of tetrahydronaphthalene is not yet ideal.

[0004] Chinese patent application 200510041404.6 discloses a continuous hydrogenation method for naphthalene, using decahydronaphthalene or tetrahydronaphthalene as the solvent for naphthalene and employing platinum-aluminum or nickel-aluminum catalysts at 2–15 MPa, 120–280 °C, and a liquid hourly space velocity (LHSV) of 0.1–5.0 h⁻¹. -1 Under conditions of a hydrogen-to-oil volume ratio of 1 to 3000, the naphthalene conversion rate is 70% to 99%. However, the target product of the above-mentioned patented method is decahydronaphthalene, which is not suitable for the production of tetrahydronaphthalene.

[0005] CN109550525 discloses a pre-sulfurization method for a catalyst used in the preparation of tetrahydronaphthalene, involving a method for producing tetrahydronaphthalene using a sulfide-type catalyst. The pre-sulfurization process of sulfide-type catalysts is complex, and the use of sulfiding agents can lead to problems such as the treatment of hydrogen sulfide-containing tail gas. Summary of the Invention

[0006] In order to overcome the shortcomings of existing technologies such as the use of sulfide-type catalysts in naphthalene hydrogenation processes, the present invention aims to provide a method for the highly selective production of tetrahydronaphthalene through naphthalene hydrogenation that can achieve low-temperature start-up and controllable high-temperature selectivity.

[0007] To achieve the above objectives, the present invention provides a naphthalene selective hydrogenation catalyst composition comprising a first hydrogenation catalyst and a second hydrogenation catalyst, wherein the first hydrogenation catalyst comprises a first support and a Group VIII non-noble metal supported on the first support; wherein the second hydrogenation catalyst comprises a second support and a Group VIII non-noble metal and a Group IB metal supported on the second support; wherein the content of the Group VIII non-noble metal in the first hydrogenation catalyst is higher than the content of the Group VIII non-noble metal in the second hydrogenation catalyst, preferably 1.5 to 5% by weight higher.

[0008] This invention provides a method for selective hydrogenation of naphthalene to produce tetrahydronaphthalene, using the aforementioned hydrogenation catalyst composition as a catalyst. The method includes: a first hydrogenation catalyst installed in the upper layer of a reactor, a second hydrogenation catalyst installed in the lower layer of the reactor, and naphthalene being contacted and reacted with the reduced first hydrogenation catalyst and the reduced second hydrogenation catalyst sequentially from top to bottom.

[0009] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0010] (1) The active component of the naphthalene selective hydrogenation catalyst composition of the present invention is in a metallic state and does not use precious metals. It is reduced before use, and the active center can be effectively maintained. It has the characteristics of high naphthalene conversion rate and high tetrahydronaphthalene selectivity. Compared with traditional sulfidation catalysts, it avoids the problems of complicated operation, sulfur-containing gas treatment and catalyst desulfurization during the reaction process, which lead to reduced activity. The operation difficulty and reaction severity are significantly reduced.

[0011] (2) The method of the present invention can achieve low temperature start-up and high temperature selectivity controllability, and has a high industrial application prospect. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the catalyst combination in Example 1. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] This invention provides a naphthalene selective hydrogenation catalyst composition, which comprises a first hydrogenation catalyst and a second hydrogenation catalyst.

[0015] The first hydrogenation catalyst contains a first support and a Group VIII non-noble metal supported on the first support.

[0016] The second hydrogenation catalyst contains a second support and a Group VIII non-noble metal and a Group IB metal supported on the second support.

[0017] The content of Group VIII non-precious metals in the first hydrogenation catalyst is higher than that in the second hydrogenation catalyst, preferably by 1.5 to 5% by weight.

[0018] The active component of the naphthalene selective hydrogenation catalyst composition of this invention is in a metallic state and does not use precious metals. Pre-use reduction treatment effectively preserves the active sites, resulting in high naphthalene conversion and high selectivity for tetrahydronaphthalene. Compared with traditional sulfidation catalysts, it avoids the problems of complex operation, sulfur-containing gas handling, and catalyst desulfurization leading to reduced activity during the reaction process, significantly reducing operational difficulty and reaction severity. Using the hydrogenation catalyst composition of this invention, low-temperature start-up and controllable high-temperature selectivity for naphthalene selective hydrogenation can be achieved, demonstrating high promise for industrial applications.

[0019] In this invention, as long as the objective of this invention can be achieved, there is no particular requirement regarding the weight of Group VIII non-precious metals contained in the first hydrogenation catalyst. According to a preferred embodiment of this invention, based on the weight of the first hydrogenation catalyst, the first hydrogenation catalyst contains 6-30% by weight of Group VIII non-precious metals (in elemental terms) and 70-94% by weight of the first support. By adopting the aforementioned preferred scheme, the technical objective of low-temperature start-up and high-temperature selectivity controllable naphthalene selective hydrogenation can be achieved more effectively.

[0020] To further improve the naphthalene conversion rate and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, the first hydrogenation catalyst contains 10-25% by weight of a Group VIII non-precious metal, calculated as an element. This enables more effective achievement of the technical objectives of low-temperature start-up and high-temperature controllable selectivity in selective hydrogenation of naphthalene.

[0021] In this invention, as long as the objective of the invention can be achieved, there are no particular requirements regarding the weight of Group VIII non-precious metals and Group IB metals in the second hydrogenation catalyst. According to a preferred embodiment of the invention, based on the weight of the second hydrogenation catalyst, the second hydrogenation catalyst contains 1-30% by weight of Group VIII non-precious metals, 1-20% by weight of Group IB metals, and 50-98% by weight of the second support. By adopting the aforementioned preferred scheme, the technical objective of low-temperature start-up and high-temperature selectivity controllable naphthalene selective hydrogenation can be achieved more effectively.

[0022] To further improve the naphthalene conversion rate and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, the second hydrogenation catalyst contains, based on its weight, 5-20% by weight of Group VIII non-precious metals and 3-12% by weight of Group IB metals. This enables a more effective achievement of the technical objectives of low-temperature start-up and high-temperature controllable selectivity for selective hydrogenation of naphthalene.

[0023] To further improve the naphthalene conversion rate and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, the second hydrogenation catalyst contains, based on its weight, 10-15% by weight of Group VIII non-precious metals and 3-5% by weight of Group IB metals. This enables a more effective achievement of the technical objective of low-temperature start-up and controllable high-temperature selectivity for selective hydrogenation of naphthalene.

[0024] In this invention, as long as the objective of the invention can be achieved, there are no particular requirements for the volume ratio of the first hydrogenation catalyst to the second hydrogenation catalyst. The volume ratio of the first hydrogenation catalyst to the second hydrogenation catalyst is 1:5 to 5:1, preferably 1:3 to 3:1. By adopting the aforementioned preferred scheme, the technical objective of low-temperature start-up and high-temperature selectivity controllable naphthalene selective hydrogenation can be achieved more effectively.

[0025] To further improve the naphthalene conversion rate and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, during selective hydrogenation of naphthalene, it is sequentially contacted with the first hydrogenation catalyst and the second hydrogenation catalyst along the material flow direction. This enables more effective achievement of the technical objectives of low-temperature start-up and controllable high-temperature selectivity in selective hydrogenation of naphthalene.

[0026] According to a preferred embodiment of the present invention, in use, a first hydrogenation catalyst is installed in the upper layer and a second hydrogenation catalyst is installed in the lower layer, with naphthalene reacting sequentially with the first and second hydrogenation catalysts from top to bottom. By adopting the aforementioned preferred scheme, the naphthalene conversion rate and tetrahydronaphthalene selectivity can be further improved. This allows for a more effective achievement of the technical objective of low-temperature start-up and controllable high-temperature selectivity for selective hydrogenation of naphthalene.

[0027] In this invention, the first and second carriers can be conventional choices in the art. According to a preferred embodiment of the invention, the first and second carriers are each selected from one or more of silicon dioxide and aluminum oxide, preferably the first and second carriers are the same. By adopting the aforementioned preferred solution, the technical objective of low-temperature start-up and high-temperature selectivity controllable naphthalene selective hydrogenation can be achieved more effectively.

[0028] According to a preferred embodiment of the present invention, the Group IB metal is one or more of Cu, Ag, and Au, preferably Cu. By adopting the aforementioned preferred embodiment, the technical objective of low-temperature start-up and high-temperature selectivity controllable naphthalene selective hydrogenation can be achieved more effectively.

[0029] According to a preferred embodiment of the present invention, the Group VIII non-precious metal in the first hydrogenation catalyst and the Group VIII non-precious metal in the second hydrogenation catalyst are each selected from one or more of nickel, iron, and cobalt, preferably both selected from nickel. By adopting the aforementioned preferred embodiment, the technical objective of low-temperature start-up and high-temperature selectivity controllable naphthalene selective hydrogenation can be achieved more effectively.

[0030] In this invention, the preparation method of the first hydrogenation catalyst can be a conventional method in the art. According to a preferred embodiment of this invention, the preparation method of the first hydrogenation catalyst includes: preparing a metal complex aqueous solution by combining a group VIII non-noble metal element compound with a complexing agent, then loading it onto a first support, drying, and calcining. By adopting the aforementioned preferred scheme, the naphthalene conversion rate and tetrahydronaphthalene selectivity can be further improved.

[0031] To further improve the naphthalene conversion rate and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, in the preparation method of the first hydrogenation catalyst, the concentration of the complexing agent in the metal complex aqueous solution is 15-40% by weight. By adopting the aforementioned preferred scheme, the naphthalene conversion rate and tetrahydronaphthalene selectivity can be further improved. This allows for a more effective achievement of the technical objective of low-temperature start-up and high-temperature selectivity controllable naphthalene selective hydrogenation.

[0032] To further improve the naphthalene conversion rate and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, the weight ratio of the metal complex aqueous solution to the saturated adsorption capacity of the first support is 10:1 to 1:1. By adopting the aforementioned preferred scheme, the naphthalene conversion rate and tetrahydronaphthalene selectivity can be further improved. This allows for a more effective achievement of the technical objective of low-temperature start-up and high-temperature selectivity controllable naphthalene selective hydrogenation.

[0033] In this invention, there are no special requirements for drying conditions. In order to further improve the naphthalene conversion rate and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, the drying conditions include maintaining the temperature at 50°C to 300°C for 1 to 48 hours.

[0034] In this invention, there are no special requirements for the calcination conditions. In order to further improve the naphthalene conversion rate and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, the calcination conditions include maintaining the temperature at 300℃ to 700℃ for 0.5h to 10.0h.

[0035] To further improve naphthalene conversion and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, the complexing agent comprises a polyamine complexing agent; preferably, the complexing agent is ethylenediamine. By adopting the aforementioned preferred embodiment, the naphthalene conversion and tetrahydronaphthalene selectivity can be further improved. This allows for a more effective achievement of the technical objective of low-temperature start-up and high-temperature selectivity controllable naphthalene selective hydrogenation.

[0036] In this invention, the preparation method of the second hydrogenation catalyst can be a conventional method in the art. According to a preferred embodiment of the invention, the preparation method of the second hydrogenation catalyst includes: preparing a metal complex aqueous solution by combining a Group VIII non-noble metal element compound, a Group IB metal element compound, and a complexing agent, then loading the solution onto a second support, followed by drying and calcination. By adopting the aforementioned preferred scheme, the naphthalene conversion rate and tetrahydronaphthalene selectivity can be further improved. This enables a more effective achievement of the technical goal of low-temperature start-up and high-temperature controllable selectivity for selective hydrogenation of naphthalene.

[0037] To further improve the naphthalene conversion rate and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, in the preparation method of the second hydrogenation catalyst, the concentration of the complexing agent in the metal complex aqueous solution is 15-40% by weight. This enables more effective achievement of the technical objective of low-temperature start-up and high-temperature selectivity controllable naphthalene selective hydrogenation.

[0038] To further improve the naphthalene conversion rate and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, the weight ratio of the metal complex aqueous solution to the saturated adsorption capacity of the second support is 10:1 to 1:1. This enables a more effective achievement of the technical objective of low-temperature start-up and high-temperature selectivity controllable naphthalene selective hydrogenation.

[0039] In this invention, there are no special requirements for the drying conditions. In order to further improve the naphthalene conversion rate and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, the drying conditions include: maintaining a temperature of 50°C to 300°C for 1 to 48 hours.

[0040] In this invention, there are no special requirements for the calcination conditions. In order to further improve the naphthalene conversion rate and tetrahydronaphthalene selectivity, according to a preferred embodiment of this invention, the calcination conditions include: maintaining at 300℃ to 700℃ for 0.5h to 10.0h.

[0041] To further improve naphthalene conversion and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, the complexing agent comprises a polyamine complexing agent; preferably, the complexing agent is ethylenediamine. This enables a more effective achievement of the technical objectives of low-temperature start-up and high-temperature controllable selectivity in selective hydrogenation of naphthalene.

[0042] This invention does not impose special requirements on the preparation methods of the first and second carriers. For example, carrier sources, acid solutions, extrusion aids, etc., can be mixed and kneaded, then shaped, such as extruded into strips, and then dried and calcined. The aforementioned preparation methods can use commonly used substances and conditions in the art, which will not be described in detail here.

[0043] This invention provides a method for selective hydrogenation of naphthalene to produce tetrahydronaphthalene, using the aforementioned hydrogenation catalyst composition as the catalyst. The method includes: a first hydrogenation catalyst installed in the upper layer of a reactor, and a second hydrogenation catalyst installed in the lower layer of the reactor; naphthalene reacting sequentially from top to bottom with the reduced first hydrogenation catalyst and the reduced second hydrogenation catalyst. This method more effectively achieves the technical objectives of low-temperature start-up and controllable high-temperature selectivity in the selective hydrogenation of naphthalene.

[0044] This invention discloses a method for selective hydrogenation of naphthalene to produce tetrahydronaphthalene. The upper layer of the reactor contains a reduced-state first hydrogenation catalyst, which has the advantage of a low activation temperature, and low-temperature hydrogenation is beneficial for obtaining higher tetrahydronaphthalene selectivity. The lower layer of the reactor contains a bimetallic reduced-state second hydrogenation catalyst. This achieves the technical effect of low-temperature start-up and controllable high-temperature selectivity, and also features high naphthalene conversion and high tetrahydronaphthalene selectivity.

[0045] In this invention, as long as the objective of this invention can be achieved, there are no special requirements for the operating conditions within the reactor. According to a preferred embodiment of this invention, the operating conditions within the reactor include: the reduction conditions for the reduced first hydrogenation catalyst and the reduced second hydrogenation catalyst include: heating to a reduction temperature of 150–450°C at a heating rate of 1–20°C / min under a reducing atmosphere, a reduction pressure of 0.5–1.5 MPa, and a reducing gas volume hourly space velocity of 50–200 h⁻¹. -1 The reduction time is 1–20 h; preferably, the reducing atmosphere is a hydrogen atmosphere; the conditions for the contact reaction include: a reaction temperature of 30–350 °C, and / or a reaction pressure of 0.5–5.0 MPa, and a volume hourly space velocity of 0.5–5.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200–1000. By adopting the aforementioned preferred scheme, the naphthalene conversion rate and tetrahydronaphthalene selectivity can be further improved.

[0046] To further improve naphthalene conversion and tetrahydronaphthalene selectivity, according to a preferred embodiment of the present invention, the operating conditions within the reactor include a reaction temperature of 80–200°C, and / or a reaction pressure of 1.0–3.5 MPa, and / or a volume hourly space velocity of 1.0–3.0 h⁻¹. -1 And / or the hydrogen-to-oil volume ratio is 400–800.

[0047] The present invention will be further illustrated by the following embodiments, but it should not be considered that the present invention is limited to the following embodiments.

[0048] The catalyst of this invention was evaluated using a 100ml fixed-bed adiabatic reactor. The catalyst loading was 100ml. Before feeding, the catalyst underwent reduction and activation treatment, and the evaluation results are shown in Table 1. Two hours after the initial reaction, the product composition was analyzed, and the conversion rate of naphthalene and the selectivity of tetrahydronaphthalene were calculated. The specific calculation method is as follows:

[0049] Naphthalene conversion rate = [(weight of naphthalene in feed - weight of naphthalene in product) / weight of naphthalene in feed] × 100%

[0050] Tetrahydronaphthalene selectivity = (moles of tetrahydronaphthalene in the product / moles of naphthalene converted) × 100%.

[0051] Example 1

[0052] The preparation steps of the catalyst in this embodiment are as follows:

[0053] Preparation of the first hydrogenation catalyst in the upper bed:

[0054] (1) Take 50g of pure alumina-type boehmite, 0.5g of nitric acid solution, 0.1g of phosphoric acid, 1.5g of guar gum powder and 56g of water, mix them thoroughly, and then extrude them into cylindrical strips (1.2mm in diameter). After drying at 120℃ for 8 hours and calcining at 550℃ for 3 hours, the first catalyst support, alumina, is obtained.

[0055] (2) Dissolve 37.5 g of nickel nitrate hexahydrate in an aqueous solution containing ethylenediamine (concentration of 25 wt%) to prepare a complex impregnation solution. Prepare the catalyst by the equal volume impregnation method. In a rotary kiln, spray the above salt solution onto the support prepared in step (1), rotate and stir for 1 hour, dry at 110°C for 8 hours, and calcine at 450°C for 4 hours to obtain the catalyst, in which the nickel content is 15 wt.% and the number is Cat-1A.

[0056] Preparation of the second hydrogenation catalyst in the lower bed:

[0057] (1) Take 50.8 g of silica, 3.3 g of sodium hydroxide, 4 g of guar gum powder and 46 g of water and mix them thoroughly. Then, extrude them into cylindrical strips (1.2 mm in diameter). After drying at 120°C for 8 hours and calcining at 550°C for 3 hours, the second catalyst support, silica, is obtained.

[0058] (2) Dissolve 37.2 g of nickel nitrate hexahydrate and 9.5 g of copper nitrate trihydrate in an aqueous solution containing ethylenediamine (concentration of 25 wt%) to prepare a complex impregnation solution. Prepare the catalyst by the equal volume impregnation method. In a rotary kiln, spray the above salt solution onto the support prepared in step (1), stir for 1 hour, dry at 110°C for 8 hours, and calcine at 450°C for 4 hours to obtain the catalyst, in which the nickel content is 13 wt.% and the copper content is 5 wt.%, and the number is Cat-1B.

[0059] The total catalyst loading is 100 ml, with the upper bed first hydrogenation catalyst Cat-1A loading volume at 50 ml and the lower bed second hydrogenation catalyst Cat-1B loading volume at 50 ml (e.g., Figure 1 As shown in the figure, the volume ratio of the two catalysts is 1:1.

[0060] The catalyst reduction conditions were as follows: reduction under a hydrogen atmosphere, with the temperature increased to 420°C at a rate of 10°C / min, a pressure of 0.5 MPa, and a hydrogen volume hourly space velocity of 125 h⁻¹. -1 The reaction was carried out for 8 hours to complete the reduction, and then cooled to the reaction temperature. The hydrogenation evaluation conditions were: reaction temperature 90℃, reaction pressure 2.5MPa, and volume hourly space velocity (VHSV) 2.5h⁻¹. -1 The hydrogen-to-oil ratio was 500, and the results after 2 hours of reaction were analyzed. The results are shown in Table 1.

[0061] Example 2

[0062] Similar to Example 1, except for the change in catalyst loading ratio: the upper bed catalyst Cat-1A was loaded with a volume of 33 ml, and the lower bed catalyst Cat-1B was loaded with a volume of 67 ml, with a loading ratio of 1:2. The reduction conditions and hydrogenation evaluation conditions of the catalysts were the same as in Example 1, and the results are shown in Table 1.

[0063] Example 3

[0064] Similar to Example 1, except for the change in catalyst loading ratio: the upper bed catalyst Cat-1A was loaded with a volume of 67 ml, and the lower bed catalyst Cat-1B was loaded with a volume of 33 ml, with a loading ratio of 2:1. The reduction conditions and hydrogenation evaluation conditions of the catalysts were the same as in Example 1, and the results are shown in Table 1.

[0065] Example 4

[0066] Same as Example 1, except that the nickel salt used in the preparation of the upper and lower bed catalysts is nickel chloride, and the copper salt used in the preparation of the lower bed catalyst is copper acetate. The prepared upper bed catalyst is labeled Cat-2A and the lower bed catalyst is labeled Cat-2B. The catalyst loading ratio is the same as in Example 1. The catalyst reduction conditions and hydrogenation evaluation conditions are the same as in Example 1. The results are shown in Table 1.

[0067] Comparative Example 1

[0068] The catalyst preparation method for this comparative example is the same as in Example 1, except that only a single-stage Cat-1A catalyst is used in the entire 100ml bed. The reduction conditions and hydrogenation evaluation conditions of the catalyst are the same as in Example 1, and the results are shown in Table 1.

[0069] Comparative Example 2

[0070] The catalyst preparation method for this comparative example is the same as in Example 1, except that only a single-stage Cat-1B catalyst is used in the entire 100ml bed. The reduction conditions and hydrogenation evaluation conditions of the catalyst are the same as in Example 1, and the results are shown in Table 1.

[0071] Example 5

[0072] Similar to Example 1, except that in the preparation of the second hydrogenation catalyst, the mass of nickel nitrate hexahydrate was 28.89 g and the mass of copper nitrate trihydrate was 6.08 g (the catalyst contained 10 wt.% nickel and 3 wt.% copper). The prepared second hydrogenation catalyst was labeled Cat-3B, the catalyst matching was Cat-1A / Cat-3B, the catalyst loading ratio was the same as in Example 1, and the reduction conditions and hydrogenation evaluation conditions were the same as in Example 1. The results are shown in Table 1.

[0073] Example 6

[0074] Same as Example 1, except that in the preparation of the first hydrogenation catalyst, the mass of nickel nitrate hexahydrate was 43.76 g (the nickel content in the catalyst was 18 wt.%), the prepared first hydrogenation catalyst was labeled Cat-3A, the catalyst matching was Cat-3A / Cat-1B, the loading ratio was the same as in Example 1, and the reduction conditions and hydrogenation evaluation conditions of the catalyst were the same as in Example 1. The results are shown in Table 1.

[0075] Example 7

[0076] Same as Example 1, except that the nickel content in the first hydrogenation catalyst is 25 wt.%, the catalyst is labeled Cat-4A, the catalyst matching is Cat-4A / Cat-1B, the loading ratio is the same as in Example 1, and the reduction conditions and hydrogenation evaluation conditions of the catalyst are the same as in Example 1. The results are shown in Table 1.

[0077] Example 8

[0078] Same as Example 1, except that the nickel content in the second hydrogenation catalyst is 4 wt.% and the copper content is 13 wt.%, the catalyst is labeled Cat-4B, the catalyst matching is Cat-1A / Cat-4B, the loading ratio is the same as in Example 1, and the catalyst reduction conditions and hydrogenation evaluation conditions are the same as in Example 1. The results are shown in Table 1.

[0079] Comparative Example 3

[0080] Same as Example 1, except that the nickel content in the first hydrogenation catalyst is 10 wt.%, the catalyst is labeled Cat-5A, the catalyst matching is Cat-5A / Cat-1B, the loading ratio is the same as in Example 1, and the reduction conditions and hydrogenation evaluation conditions of the catalyst are the same as in Example 1. The results are shown in Table 1.

[0081] Table 1 Evaluation results of different catalysts

[0082]

[0083] As shown in Table 1, the catalyst composition of the present invention exhibits excellent reaction performance in the selective hydrogenation of naphthalene to produce tetrahydronaphthalene, with both naphthalene conversion and selectivity for the target product tetrahydronaphthalene exceeding 95%. Table 1 also shows that, using the combined catalyst within the preferred ratio range, the naphthalene conversion is >95%, and the selectivity for the target product tetrahydronaphthalene is >98%.

[0084] The catalyst of this invention has significant performance advantages in the reaction of naphthalene hydrogenation to produce tetrahydronaphthalene. Compared with sulfidation catalysts, the catalyst does not require a pre-sulfidation process before use, the tail gas does not need to be treated, and the operating cost is significantly reduced.

[0085] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for selective hydrogenation of naphthalene to produce tetrahydronaphthalene, characterized in that, Using a hydrogenation catalyst composition as a catalyst, the catalyst composition containing a first hydrogenation catalyst and a second hydrogenation catalyst, the method includes: the first hydrogenation catalyst being installed in the upper layer of a reactor, the second hydrogenation catalyst being installed in the lower layer of a reactor, and naphthalene being contacted and reacted with the reduced first hydrogenation catalyst and the reduced second hydrogenation catalyst sequentially from top to bottom; The first hydrogenation catalyst contains a first support and a Group VIII non-noble metal supported on the first support. The second hydrogenation catalyst contains a second support and a Group VIII non-noble metal and a Group IB metal supported on the second support. The content of Group VIII non-precious metals in the first hydrogenation catalyst is 1.5-5% higher than that in the second hydrogenation catalyst. Based on the weight of the first hydrogenation catalyst, the first hydrogenation catalyst contains 6-30% by weight of Group VIII non-precious metals (based on elemental composition) and 70-94% by weight of the first support; Based on the weight of the second hydrogenation catalyst, the second hydrogenation catalyst contains 1-30% by weight of Group VIII non-precious metals, 1-20% by weight of Group IB metals, and 50-98% by weight of the second support; The volume ratio of the first hydrogenation catalyst to the second hydrogenation catalyst is 1:5 to 5:1; The preparation method of the first hydrogenation catalyst includes: preparing a metal complex aqueous solution by combining a group VIII non-precious metal element compound with a complexing agent, loading it onto a first support, drying and calcining. The preparation method of the second hydrogenation catalyst includes: preparing a metal complex aqueous solution by combining a group VIII non-precious metal element compound, a group IB metal element compound and a complexing agent, then loading it onto a second support, and drying and calcining it.

2. The method according to claim 1, wherein, Based on the weight of the first hydrogenation catalyst, the first hydrogenation catalyst contains 10 to 25% by weight of Group VIII non-precious metals.

3. The method according to claim 1, wherein, Based on the weight of the second hydrogenation catalyst, the second hydrogenation catalyst contains 5 to 20% by weight of Group VIII non-precious metals and 3 to 12% by weight of Group IB metals.

4. The method according to claim 3, wherein, Based on the weight of the second hydrogenation catalyst, the second hydrogenation catalyst contains 10-15% by weight of Group VIII non-precious metals and 3-5% by weight of Group IB metals.

5. The method according to claim 1, wherein, The volume ratio of the first hydrogenation catalyst to the second hydrogenation catalyst is 1:3 to 3:

1.

6. The method according to claim 1, wherein, The first carrier and the second carrier are each selected from one or more of silicon dioxide and aluminum oxide; and / or The Group IB metal is one or more of Cu, Ag, and Au; and / or The Group VIII non-precious metal in the first hydrogenation catalyst and the Group VIII non-precious metal in the second hydrogenation catalyst are each selected from one or more of nickel, iron, and cobalt.

7. The method according to claim 6, wherein, The first carrier and the second carrier are the same; and / or The Group IB metal is Cu; and / or Both the Group VIII non-precious metal in the first hydrogenation catalyst and the Group VIII non-precious metal in the second hydrogenation catalyst are selected from nickel.

8. The method according to claim 1, wherein, In the preparation method of the first hydrogenation catalyst, The concentration of the complexing agent in the metal complex aqueous solution is 15-40% by weight; and / or The volume ratio of the metal complex aqueous solution to the saturated adsorption capacity of the first carrier is 10:1 to 1:1; and / or The drying conditions include: maintaining a temperature of 50℃ to 300℃ for 1 hour to 48 hours; and / or The calcination conditions include: maintaining the temperature at 300℃ to 700℃ for 0.5h to 10.0h; and / or The complexing agent includes a polyamine complexing agent.

9. The method according to claim 8, wherein, The complexing agent is ethylenediamine.

10. The method according to claim 1, wherein, In the preparation method of the second hydrogenation catalyst, The concentration of the complexing agent in the metal complex aqueous solution is 15-40% by weight; and / or The volume ratio of the metal complex aqueous solution to the saturated adsorption capacity of the second carrier is 10:1 to 1:1; and / or The drying conditions include: maintaining a temperature of 50℃ to 300℃ for 1 hour to 48 hours; and / or The calcination conditions include: maintaining the temperature at 300℃ to 700℃ for 0.5h to 10.0h; and / or The complexing agent includes a polyamine complexing agent.

11. The method according to claim 10, wherein, The complexing agent is ethylenediamine.

12. The method according to claim 1, wherein, The operating conditions within the reactor include: The reduction conditions for the reduced first hydrogenation catalyst and the reduced second hydrogenation catalyst include: heating to a reduction temperature of 150–450°C at a heating rate of 1–20°C / min under a reducing atmosphere, a reduction pressure of 0.5–1.5 MPa, and a reducing gas volume hourly space velocity of 50–200 h⁻¹. -1 The restoration time is 1–20 hours; The conditions for the contact reaction include: a reaction temperature of 30–350°C, and / or a reaction pressure of 0.5–5.0 MPa, and a volume hourly space velocity of 0.5–5.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200–1000.

13. The method according to claim 12, wherein, The reducing atmosphere is a hydrogen atmosphere.

14. The method according to claim 12, wherein, The operating conditions within the reactor include: The reaction temperature is 80–200℃, and / or the reaction pressure is 1.0–3.5 MPa, and / or the volume hourly space velocity is 1.0–3.0 h⁻¹. -1 And / or the hydrogen-to-oil volume ratio is 400–800.

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