Hydrocracking isomerization catalyst as well as preparation method and application thereof

Abstract

The invention discloses a hydrocracking isomerization catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalysts. The preparation method comprises the following steps: S1, carrying out modification treatment on a ZSM-48 molecular sieve in the presence of an alkali solution to obtain slurry, adjusting the pH value of the slurry to 0.5-2, and then adding tetraethyl silicate and a block copolymer P123 for crystallization treatment to obtain a composite molecular sieve; s2, mixing the composite molecular sieve with an alumina-containing substance, carrying out molding treatment, drying, and roasting to obtain a carrier; and S3, loading a noble metal on the carrier to obtain the hydrocracking isomerization catalyst. The catalyst has an excellent cracking isomerization function. When the hydrocracking isomerization catalyst is applied to fischer-tropsch wax cracking isomerization production of cracked products, jet fuel and diesel oil obtained through cracking are high in yield and low in freezing point, and meanwhile, the pour point of the byproduct base oil also meets the requirement.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and particularly relates to a hydrocracking isomerization catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] The indirect coal liquefaction technology converts syngas into Fischer-Tropsch wax products through the Fischer-Tropsch synthesis process, and further obtains refined Fischer-Tropsch wax through processing. It has the characteristics of a high content of saturated chain hydrocarbons (>99%), and is very suitable for producing products such as base oils with high viscosity index and low pour point, low-freezing diesel, and low-freezing aviation kerosene. However, the high melting point (80-90°C) and wide distillation range (350-700°C) of refined Fischer-Tropsch wax make it difficult to balance the production of oil products in different distillation segments, and it is more difficult for each distillation fraction of oil products to have excellent low-temperature fluidity (low pour point, low freezing point, low ice point, etc.).

[0003] To solve the above problems, in the prior art, processing routes such as hydroisomerization or hydrocracking are adopted to convert Fischer-Tropsch wax into products such as fuel oil and lubricating oil base oil. Among them, the isomerization process usually cuts out light narrow fraction Fischer-Tropsch wax (350-550°C) from the whole fraction of refined wax as raw material. At this time, the melting point of the raw material drops to 60-70°C, and the isomerization processing difficulty is reduced. The problem with this route is that the melting point of the remaining heavy Fischer-Tropsch wax (550-700°C) after cutting reaches above 100°C, and it is more difficult to process and convert it into oil products. There is currently no technical report on the conversion and application of this section of raw material; for the cracking process, the whole fraction of Fischer-Tropsch wax is cracked into products such as naphtha and diesel. Even if some lubricating oil base oil fraction products are by-produced, due to the weak isomerization function, the pour points (or freezing points) of the obtained cracking fuels and base oils are not good.

[0004] Chinese Patent Application Document CN106513035A discloses a material composed of an isomerization molecular sieve and a mesoporous molecular sieve, which is used for isomerization to produce lubricating oil base oil, but it does not have selectivity for the cracking product distribution.

[0005] Chinese Patent Application Document CN113019426A discloses a micro-mesoporous composite molecular sieve catalyst with cracking function, but it does not have excellent selectivity for isomerization products.

[0006] Therefore, the catalysts disclosed in the prior art have problems such as poor selectivity for isomerization products and poor selectivity for cracking product distribution. Summary of the Invention

[0007] To solve the above problems existing in the prior art, the present invention provides a hydrocracking isomerization catalyst, a preparation method thereof, and an application thereof. The hydrocracking isomerization catalyst obtained by the preparation method of the present invention simultaneously takes into account excellent selectivity for isomerization products and selectivity for cracking product distribution.

[0008] In a first aspect, the present invention provides a method for preparing a hydrocracking isomerization catalyst, which comprises the following steps:

[0009] S1. Modify the ZSM-48 molecular sieve in the presence of an alkali solution to obtain a slurry; adjust the pH value of the slurry to 0.5 - 2, for example, it can be 0.5, 0.7, 0.8, 1, 1.3, 1.5, 1.7, 2 or other values within this range, preferably 0.8 - 1.5; preferably, for example, the pH value can be adjusted with hydrochloric acid; then add tetraethyl orthosilicate and block copolymer P123 for crystallization treatment to obtain a composite molecular sieve;

[0010] S2. Mix the composite molecular sieve with an alumina-containing substance and then carry out shaping treatment. After drying and calcination, a support is obtained;

[0011] S3. Load noble metals on the support to obtain a hydrocracking isomerization catalyst.

[0012] In the preparation method provided by the present invention, first, the isotypic microporous molecular sieve ZSM-48 is modified in the presence of an alkali solution and fragmented to obtain a semi-amorphous slurry containing ZSM-48 molecular sieve microcrystals. Using this slurry as a partial silicon source, after adjusting the pH, it is mixed with a certain proportion of tetraethyl orthosilicate, and then block copolymer P123 is added. After crystallization, a ZSM-48 / SBA-15 type composite molecular sieve is obtained. Some of the acidic sites in this composite molecular sieve still retain excellent isomeric acid functions, while some other free acidic sites become the basic structural units of SBA-15, making the isomerization and cracking functions closer and having a better synergistic effect; finally, a hydrocracking isomerization catalyst is prepared by impregnating with a noble metal salt, which has excellent cracking and isomerization functions.

[0013] In some embodiments, in step S1, the alkali solution is an inorganic alkali solution.

[0014] In some preferred embodiments, the inorganic alkali solution is an NaOH solution and / or a KOH solution.

[0015] In some preferred embodiments, the concentration of the alkali solution is 0.5 - 2 mol / L, for example, it can be 0.5 mol / L, 0.7 mol / L, 0.9 mol / L, 1 mol / L, 1.3 mol / L, 1.5 mol / L, 1.7 mol / L, 2 mol / L or other values within this range;

[0016] In the present invention, the inventors have found through research that if the concentration of the alkali solution is too low, the modification reaction will not be complete, resulting in a certain degree of decline in the cracking and isomerization functions of the hydrocracking isomerization catalyst prepared; if the concentration of the alkali solution is too high, the structure of the molecular sieve will be damaged, greatly reducing the performance of the hydrocracking isomerization catalyst prepared.

[0017] In some preferred embodiments, the mass ratio of the ZSM-48 molecular sieve to the alkali solution is 1:(2 - 20), for example, it can be 1:2, 1:5, 1:8, 1:10, 1:12, 1:15, 1:18, 1:20 or other values within this range.

[0018] In some more preferred embodiments, the mass ratio of the ZSM-48 molecular sieve to the alkali solution is 1:(10 - 15).

[0019] In some preferred embodiments, the temperature of the modification treatment is 60 - 90°C, for example, it can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C or other values within this range, preferably 80°C; the time is 1 - 24 h, for example, it can be 1 h, 3 h, 6 h, 8 h, 10 h, 13 h, 15 h, 18 h, 21 h, 24 h or other values within this range, preferably 6 - 10 h.

[0020] In some embodiments, in step S1, the mass ratio of the silicon content in tetraethyl orthosilicate to the ZSM-48 molecular sieve is (2 - 20):1, for example, it can be 2:1, 5:1, 8:1, 10:1, 12:1, 14:1, 16:1, 18:1, 20:1 or other values within this range, preferably (5 - 10):1; and / or,

[0021] The mass ratio of the block copolymer P123 to the total amount of tetraethyl orthosilicate and the ZSM-48 molecular sieve is (0.8 - 1.5):1, for example, it can be 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1 or other values within this range.

[0022] In some preferred embodiments, the temperature of the crystallization treatment is 80 - 140°C, for example, it can be 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C or other values within this range, preferably 100°C; the time is 12 - 72 h, for example, it can be 12 h, 22 h, 24 h, 32 h, 42 h, 52 h, 62 h, 72 h or other values within this range, preferably 24 h.

[0023] In some embodiments, in step S2, calculated on a dry basis, in the carrier, the weight percentage of the composite molecular sieve is 50-90%, for example, it can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or other values within this range, and preferably 70%.

[0024] In the present invention, the inventors have found through research that in the carrier, if the content of the composite molecular sieve is relatively high, the content of the alumina-containing substance is relatively low, which is not conducive to the subsequent shaping of the catalyst; if the content of the composite molecular sieve is relatively low, the activity of the prepared hydrocracking isomerization catalyst will decrease.

[0025] In some more preferred embodiments, the alumina-containing substance is pseudo-boehmite.

[0026] In some embodiments, in step S2, the shaping treatment includes:

[0027] Adding a nitric acid solution to the mixture of the composite molecular sieve and the alumina-containing substance until the powder is kneaded into a mass, wherein the mass ratio of nitric acid to the mixture in the nitric acid solution is (0.01-0.05):1; then extruding and shaping to obtain a bar-shaped carrier.

[0028] In some preferred embodiments, the drying temperature is 100-140 °C, for example, it can be 100 °C, 110 °C, 120 °C, 130 °C, 140 °C or other values within this range, and preferably 120 °C; the time is 8-48 h, for example, it can be 8 h, 12 h, 15 h, 20 h, 24 h, 30 h, 35 h, 40 h, 45 h, 48 h or other values within this range, and preferably 12-24 h; and / or,

[0029] The calcination temperature is 400-700 °C, for example, it can be 400 °C, 450 °C, 500 °C, 550 °C, 600 °C, 650 °C, 700 °C or other values within this range, and preferably 550 °C; the time is 2-8 h, for example, it can be 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h or other values within this range, and preferably 4 h.

[0030] In some embodiments, in step S3, the mass ratio of the noble metal to the carrier is (0.001-0.006):1; for example, it can be 0.001:1, 0.002:1, 0.003:1, 0.0035:1, 0.005:1, 0.006:1 or other values within this range,

[0031] In some preferred embodiments, the noble metal is Pt and / or Pd.

[0032] In some embodiments, in step S3, loading the noble metal onto the carrier includes using the incipient wetness impregnation method, mixing the noble metal salt solution with the carrier, and completing the loading through the steps of drying and calcination.

[0033] In the present invention, the incipient wetness impregnation method is a conventional method in the art. For example, it can be first to measure the pore volume value per unit mass of the carrier by a nitrogen physical adsorption instrument, thereby calculating the total pore volume of the carrier under a certain mass, preparing a noble metal salt solution with the same volume, and then mixing it with the carrier. The methods of drying and calcination are both conventional methods in the art. For example, the drying temperature can be 120 °C and the time can be 12 h; the calcination temperature can be 550 °C and the time can be 4 h.

[0034] In some embodiments, the noble metal salt solution is selected from one or more of chloroplatinic acid solution, dichlorotetraammineplatinum solution, and tetraammineplatinum nitrate solution.

[0035] In a second aspect, the present invention provides a hydrocracking isomerization catalyst prepared by using the preparation method of any one of the above-mentioned hydrocracking isomerization catalysts.

[0036] In some embodiments, the pore diameter of the hydrocracking isomerization catalyst is 6 - 7 nm, the specific surface area is 450 - 520 m 2 / g, the pore volume is 0.5 - 0.6 cm 3 / g, the amount of weak acid is 0.2 - 0.3 mmol / g, and the amount of strong acid is 0.1 - 0.2 mmol / g.

[0037] In a third aspect, the present invention provides the application of the above-mentioned hydrocracking isomerization catalyst in the cracking isomerization of Fischer-Tropsch wax.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The hydrocracking isomerization catalyst prepared by a specific method in the present invention has excellent cracking isomerization functions. When this hydrocracking isomerization catalyst is applied to the cracking isomerization of Fischer-Tropsch wax to produce cracked products, the yields of jet fuel and diesel obtained by cracking are high, the freezing point (or ice point) is low, and at the same time, the pour point of the by-produced base oil also meets the requirements. Detailed Embodiments

[0040] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0041] For the experimental methods without specific conditions noted in the examples, they are generally carried out according to the conventional conditions and the conditions described in the manual, or according to the conditions recommended by the manufacturer. For general equipment, materials, reagents, etc., if there is no special description, they can all be obtained commercially.

[0042] Some of the test methods in the present invention are as follows:

[0043] The specific surface area, pore volume, and pore diameter are tested by the conventional BET analysis method; a nitrogen physical adsorption instrument is used to analyze the nitrogen adsorption-desorption isotherm of the test sample, and the BET and t-plot analysis methods provided by the instrument are used for calculation.

[0044] The acidic properties of the catalyst are tested by the conventional ammonia adsorption-desorption method (NH3-TPD); the sample to be tested is saturated with ammonia adsorption, and then the adsorbed ammonia is gradually released by heating, and the amount of desorbed ammonia is recorded with a TCD detector. The amount of ammonia desorbed at low temperature (100-300 °C) represents the amount of weak acid in the sample, and the amount of ammonia desorbed at high temperature (300-600 °C) represents the amount of strong acid in the sample.

[0045] The product distribution is obtained by true boiling point distillation analysis; it is tested by referring to the methods in ASTM D2892 and ASTM D5236.

[0046] The pour point (or freezing point) of the product is obtained by testing with an automatic pour point tester; it is tested by referring to the method in GB / T26985-2018.

[0047] The performance of the catalyst is obtained by the micro-reaction hydrocracking isomerization test of Fischer-Tropsch wax; the catalyst is loaded into the reaction tube of a fixed-bed reactor, using Fischer-Tropsch wax as the raw material and hydrogen as the carrier gas. At a certain temperature, it continuously passes through the reaction tube filled with the catalyst, and the product obtained is subjected to true boiling point distillation analysis to obtain the product distribution data. The low-temperature fluidity analysis is carried out on the products of different distillation fractions obtained by distillation to obtain indicators such as the pour point and freezing point of the product.

[0048] The calculation formulas are as follows: cracking rate = (mass of fractions less than 370 °C in cracking products / total product mass) * 100%;

[0049] Selectivity of middle oil fraction = (aviation kerosene + diesel fraction products (160-370 °C fraction)) / mass of fractions less than 370 °C in cracking products / total product mass * 100%;

[0050] Yield of base oil fraction = 100% - cracking rate.

[0051] Example 1

[0052] A preparation method of a hydrocracking isomerization catalyst includes the following steps:

[0053] S1. Mix the ZSM-48 molecular sieve with a NaOH solution at a concentration of 0.5 mol / L in a mass ratio of 1:5, and then conduct a modification treatment. Among them, the temperature of the modification treatment is 85 °C and the time is 10 h to obtain a slurry. Adjust the pH value of the slurry to 0.6, and then add tetraethyl orthosilicate and block copolymer P123 for crystallization treatment. Among them, the mass ratio of the silicon content in tetraethyl orthosilicate to the ZSM-48 molecular sieve is 3:1, and the mass ratio of block copolymer P123 to the total amount of tetraethyl orthosilicate and ZSM-48 molecular sieve is 0.8:1. The temperature of the crystallization treatment is 120 °C and the time is 12 h to obtain a composite molecular sieve;

[0054] S2. Mix 80 wt% of the composite molecular sieve with 20 wt% of pseudo-boehmite to obtain a mixture, and dropwise add a dilute nitric acid solution until the powder is kneaded into a mass. Among them, the mass ratio of nitric acid in the nitric acid solution to the mixture is 0.015:1; then extrude into a shape to prepare a bar-shaped carrier, dry it at a temperature of 100 °C for 48 h, and calcine it at a temperature of 500 °C for 6 h to obtain a carrier;

[0055] S3. Load Pt on the carrier by the conventional equal-volume impregnation method. Among them, the mass ratio of the noble metal to the carrier is 0.005:1 to obtain a hydrocracking isomerization catalyst.

[0056] Example 2

[0057] A preparation method of a hydrocracking isomerization catalyst includes the following steps:

[0058] S1. Mix the ZSM-48 molecular sieve with a NaOH solution at a concentration of 2 mol / L in a mass ratio of 1:10, and then conduct a modification treatment. Among them, the temperature of the modification treatment is 80 °C and the time is 6 h to obtain a slurry. Adjust the pH value of the slurry to 0.8, and then add tetraethyl orthosilicate and block copolymer P123 for crystallization treatment. Among them, the mass ratio of the silicon content in tetraethyl orthosilicate to the ZSM-48 molecular sieve is 5:1, and the mass ratio of block copolymer P123 to the total amount of tetraethyl orthosilicate and ZSM-48 molecular sieve is 0.8:1. The temperature of the crystallization treatment is 100 °C and the time is 24 h to obtain a composite molecular sieve;

[0059] S2. Mix 70 wt% of the composite molecular sieve with 30 wt% of pseudo-boehmite, and dropwise add a dilute nitric acid solution until the powder is kneaded into a mass. Among them, the mass ratio of nitric acid in the nitric acid solution to the mixture is 0.02:1; then extrude into a shape to prepare a bar-shaped carrier, dry it at a temperature of 120 °C for 24 h, and calcine it at a temperature of 550 °C for 4 h to obtain a carrier;

[0060] S3. Load Pt on the support by the conventional equal-volume impregnation method, where the mass ratio of the noble metal to the support is 0.0035:1 to obtain the hydrocracking isomerization catalyst.

[0061] Example 3

[0062] A preparation method of a hydrocracking isomerization catalyst includes the following steps:

[0063] S1. Mix ZSM-48 molecular sieve with a 0.5 mol / L NaOH solution at a mass ratio of 1:15 and then perform a modification treatment. The modification treatment temperature is 80 °C and the time is 10 h to obtain a slurry. Adjust the pH value of the slurry to 1.5, and then add tetraethyl orthosilicate and block copolymer P123 for crystallization treatment. The mass ratio of the silicon content in tetraethyl orthosilicate to the mass of ZSM-48 molecular sieve is 10:1, and the mass ratio of block copolymer P123 to the total amount of tetraethyl orthosilicate and ZSM-48 molecular sieve is 0.8:1. The crystallization treatment temperature is 100 °C and the time is 48 h to obtain a composite molecular sieve.

[0064] S2. Mix 70% by weight of the composite molecular sieve with 30% by weight of pseudo-boehmite, and then add a dilute nitric acid solution dropwise until the powder is kneaded into a mass. The mass ratio of nitric acid to the mixture in the nitric acid solution is 0.03:1; then knead into a mass, and then extrude into a shape to prepare a strip-shaped support. Dry it at 120 °C for 24 h and calcine it at 550 °C for 4 h to obtain the support.

[0065] S3. Load Pt on the support by the conventional equal-volume impregnation method, where the mass ratio of the noble metal to the support is 0.0035:1 to obtain the hydrocracking isomerization catalyst.

[0066] Example 4

[0067] A preparation method of a hydrocracking isomerization catalyst includes the following steps:

[0068] S1. Mix ZSM-48 molecular sieve with a 0.5 mol / L NaOH solution at a mass ratio of 1:17 and then perform a modification treatment. The modification treatment temperature is 70 °C and the time is 10 h to obtain a slurry. Adjust the pH value of the slurry to 1.7, and then add tetraethyl orthosilicate and block copolymer P123 for crystallization treatment. The mass ratio of the silicon content in tetraethyl orthosilicate to the mass of ZSM-48 molecular sieve is 13:1, and the mass ratio of block copolymer P123 to the total amount of tetraethyl orthosilicate and ZSM-48 molecular sieve is 1.5:1. The crystallization treatment temperature is 90 °C and the time is 72 h to obtain a composite molecular sieve.

[0069] S2. Mix the composite molecular sieve with a weight percentage of 60% and pseudoboehmite with a weight percentage of 40%, then add a dilute nitric acid solution dropwise until the powder is kneaded into a mass. Among them, the mass ratio of nitric acid to the mixture in the nitric acid solution is 0.04:1. Then, extrude and shape to prepare a bar-shaped carrier, dry it at 140 °C for 12 h, and calcine it at 600 °C for 2 h to obtain the carrier.

[0070] S3. Load Pt on the carrier by the conventional equal-volume impregnation method. Among them, the mass ratio of the noble metal to the carrier is 0.002:1 to obtain a hydrocracking isomerization catalyst.

[0071] Comparative Example 1

[0072] The preparation method of the hydrocracking isomerization catalyst is basically the same as that of Example 1. The difference is that in step S1, the ZSM-48 molecular sieve is not subjected to alkali modification treatment, and the NaOH solution is directly replaced with an equal amount of water for the synthesis of the composite molecular sieve.

[0073] Comparative Example 2

[0074] The preparation method of the hydrocracking isomerization catalyst is basically the same as that of Example 1. The difference is that in step S1, the concentration of the NaOH solution is 0.4 mol / L.

[0075] Comparative Example 3

[0076] The preparation method of the hydrocracking isomerization catalyst is basically the same as that of Example 1. The difference is that in step S1, the concentration of the NaOH solution is 2.1 mol / L.

[0077] Comparative Example 4

[0078] The preparation method of the hydrocracking isomerization catalyst is basically the same as that of Example 1. The difference is that in step S1, tetraethyl orthosilicate and block copolymer P123 are mixed, the pH value is adjusted to 0.5, and crystallization treatment is carried out at a temperature of 100 °C for 24 h to obtain SBA-15 molecular sieve. The SBA-15 molecular sieve and ZSM-48 molecular sieve are mixed to obtain a composite molecular sieve. Among them, the mass ratio of the silicon content in tetraethyl orthosilicate to the ZSM-48 molecular sieve is 10:1, and the mass ratio of block copolymer P123 to the total amount of tetraethyl orthosilicate and ZSM-48 molecular sieve is 1.5:1.

[0079] Testing of catalyst performance parameters

[0080] Test the performance parameters of the hydrocracking isomerization catalysts prepared in Examples 1-4 and Comparative Examples 1-4, and the results are shown in Table 1 below.

[0081] Table 1 Test results of specific surface area, pore diameter, pore volume and acid amount of the catalyst

[0082]

[0083] As can be seen from the results in Table 1, compared with the comparative examples, the hydrocracking isomerization catalysts prepared in Examples 1-4 of the present invention have appropriate specific surface area, pore diameter, pore volume, weak acid amount and strong acid amount.

[0084] Application test of the catalyst

[0085] Using Fischer-Tropsch wax as the raw material, under the test conditions of a hydrogen partial pressure of 6 MPa, a space velocity of 1.0 h -1 , a hydrogen-oil volume ratio of 500:1, and a reaction temperature of 320 - 260 °C, the cracking and isomerization performances of the hydrocracking isomerization catalysts prepared in Examples 1-4 and Comparative Examples 1-4 were evaluated, and the results are shown in Table 2 below.

[0086] Table 2 Performance test results of the catalysts

[0087]

[0088]

[0089] As can be seen from the results in Table 2, the hydrocracking isomerization catalysts prepared in Examples 1-4 of the present invention have a high cracking rate, middle oil fraction selectivity, as well as a low solidification point of the middle oil fraction and the pour point of the base oil product. Generally, the isomer product selectivity affects the pour point of the product. If the pour point of the product is low, the degree of isomerization is high. The cracking product distribution affects the middle oil fraction selectivity. The cracking products mainly include two fractions: light oil and middle oil. If the middle oil fraction selectivity is high, the cracking product distribution selectivity is better. Therefore, the hydrocracking isomerization catalysts prepared in Examples 1-4 of the present invention take into account both excellent isomer product selectivity and cracking product distribution selectivity.

[0090] In Comparative Example 1, the ZSM-48 molecular sieve was not modified. As a result, it was found that the middle oil fraction selectivity of the prepared hydrocracking isomerization catalyst decreased significantly, and the solidification point of the middle oil fraction and the pour point of the base oil product both increased; in Comparative Examples 2 and 3, the concentration of the alkali solution was too low and too high. As a result, it was found that the middle oil fraction selectivity of the prepared hydrocracking isomerization catalyst decreased to a certain extent, and the solidification point of the middle oil fraction and the pour point of the base oil product both increased; in Comparative Example 4, SBA-15 molecular sieve was prepared first, and then mixed with ZSM-48 molecular sieve to obtain a composite molecular sieve. As a result, it was found that the middle oil fraction selectivity of the prepared hydrocracking isomerization catalyst decreased significantly, and the solidification point of the middle oil fraction and the pour point of the base oil product both increased. The results further show that the hydrocracking isomerization catalyst prepared by the preparation method of the present invention has better performance.

[0091] The above embodiments are only specific implementation manners of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting it. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: any person skilled in the technical field familiar with the present invention can still modify the technical solutions recorded in the foregoing embodiments, or can easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the protection scope of the present invention.

Claims

1. A preparation method of a hydrocracking isomerization catalyst, characterized in that, It includes the following steps: S1. Modify the ZSM-48 molecular sieve in the presence of an alkali solution to obtain a slurry; adjust the pH value of the slurry to 0.5 - 2, preferably 0.8 - 1.5; preferably, adjust the pH value with hydrochloric acid; then add tetraethyl orthosilicate and block copolymer P123 for crystallization treatment to obtain a composite molecular sieve; S2. Mix the composite molecular sieve with an alumina-containing substance and then perform shaping treatment. After drying and calcination, a carrier is obtained; S3. Load a noble metal on the carrier to obtain a hydrocracking isomerization catalyst.

2. The preparation method of the hydrocracking isomerization catalyst according to claim 1, characterized in that, In step S1, the alkali solution is an inorganic alkali solution. Preferably, the inorganic alkali solution is a NaOH solution and / or a KOH solution; Preferably, the concentration of the alkali solution is 0.5 - 2 mol / L; Preferably, the mass ratio of the ZSM-48 molecular sieve to the alkali solution is 1:(2 - 20); more preferably 1:(10 - 15); Preferably, the temperature of the modification treatment is 60 - 90 °C, preferably 80 °C; the time is 1 - 24 h, preferably 6 - 10 h.

3. The preparation method of the hydrocracking isomerization catalyst according to claim 1 or 2, characterized in that, In step S1, the mass ratio of the silicon content in tetraethyl orthosilicate to the ZSM-48 molecular sieve is (2 - 20):1, preferably (5 - 10):1; and / or, The mass ratio of the block copolymer P123 to the total amount of tetraethyl orthosilicate and the ZSM-48 molecular sieve is (0.8 - 1.5):1; Preferably, the temperature of the crystallization treatment is 80 - 140 °C, preferably 100 °C; the time is 12 - 72 h, preferably 24 h.

4. The preparation method of the hydrocracking isomerization catalyst according to any one of claims 1-3, characterized in that, In step S2, calculated on a dry basis, in the carrier, the weight percentage of the composite molecular sieve is 50 - 90%, preferably 70%; more preferably, the alumina-containing substance is pseudoboehmite.

5. The preparation method of the hydrocracking isomerization catalyst according to any one of claims 1-4, characterized in that, In step S2, the shaping treatment includes: Drop a nitric acid solution into the mixture of the composite molecular sieve and the alumina-containing substance until the powder is kneaded into a mass. Among them, the mass ratio of nitric acid in the nitric acid solution to the mixture is (0.01 - 0.05):1; then extrude and shape to prepare a bar-shaped carrier; Preferably, the temperature of the drying is 100 - 140 °C, preferably 120 °C; the time is 8 - 48 h, preferably 12 - 24 h; and / or, The temperature of the calcination is 400 - 700 °C, preferably 550 °C; the time is 2 - 8 h, preferably 4 h.

6. The preparation method of the hydrocracking isomerization catalyst according to any one of claims 1-5, characterized in that, In step S3, the mass ratio of the noble metal to the carrier is (0.001 - 0.006):1; preferably, the noble metal is Pt and / or Pd.

7. The preparation method of the hydrocracking isomerization catalyst according to any one of claims 1-6, characterized in that, In step S3, loading the noble metal on the carrier includes using the equal-volume impregnation method, mixing the noble metal salt solution with the carrier, and completing the loading through the steps of drying and calcination.

8. The preparation method of the hydrocracking isomerization catalyst according to claim 7, characterized in that, The noble metal salt solution is selected from one or more of chloroplatinic acid solution, tetraammineplatinum dichloride solution, and tetraammineplatinum nitrate solution.

9. A hydrocracking isomerization catalyst prepared by the preparation method of the hydrocracking isomerization catalyst according to any one of claims 1 - 8.

10. Use of the hydrocracking isomerization catalyst according to claim 9 in the cracking isomerization of Fischer-Tropsch wax.

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