A catalyst for the skeletal isomerization of normal alkanes, and its preparation method and application

Abstract

The present invention discloses a catalyst for the skeletal isomerization of normal alkanes, a preparation method thereof, and an application thereof in catalyzing the skeletal isomerization reaction of normal alkanes. The catalyst disclosed in the present invention comprises a ZrO2 carrier and Pt and SO4 supported thereon. 2‑ The specific surface area of ​​the catalyst is 110-130m 2 / g, with an average pore size of 5-10nm. The catalyst prepared by the present invention is insensitive to the content of impurities such as oxygen and sulfur in the raw materials. The prepared catalyst has high catalytic activity and stability in the skeletal isomerization of n-butane at low temperatures.

Description

Technical Field

[0001] The present invention belongs to the technical field of heterogeneous catalyst preparation, and particularly relates to a catalyst for normal alkane skeletal isomerization reaction, a preparation method and an application thereof. Background Art

[0002] Industrially, C4 alkanes primarily come from catalytic cracking units. Currently, alkylate production accounts for the largest scale within the C4 industry chain, followed by MTBE production. With the widespread promotion of natural gas, liquefied petroleum gas (LPG) has become the driving force behind C4 deep processing projects. Furthermore, with increasingly stringent environmental protection requirements, accelerating gasoline quality upgrades has become increasingly important. The key focus of gasoline standard upgrades is to achieve "desulfurization, manganese reduction, and olefin reduction" while maintaining octane rating. Reducing olefins and aromatics makes it difficult to meet gasoline octane standards, making the development of high-octane clean components for gasoline blending crucial. Alkylate, with its high octane rating, low volatility, absence of aromatics and olefins, and near-zero sulfur content, is highly suitable for gasoline blending. One of the feedstocks for alkylate production is isobutane, making the development of catalysts for the skeletal isomerization of n-butane to isobutane crucial for clean gasoline production.

[0003] Isomerization catalysts typically utilize platinum halide / alumina catalysts with γ-Al₂O₃ as a support. During operation, an appropriate amount of chloride additive must be continuously added to the feedstock. The main drawback of this technology is the stringent requirements for water and sulfur content in the feedstock, which must be less than 0.1 ppm. Furthermore, the chlorine-containing substances produced during the reaction are corrosive to the equipment, increasing equipment material and maintenance costs, and also causing environmental pollution.

[0004] Zirconia-supported n-butane skeletal isomerization catalysts are not only chlorine-free, but also have relaxed requirements for raw material moisture and sulfur content and are regenerable, representing a promising development direction for isomerization catalysts. Patents CN107051420A, CN10822184A, CN10807998A, and CN109772287A disclose the preparation of zirconium oxide-based solid superacid catalysts and their application in alkane isomerization. Existing technologies often focus on catalyst activity, but lack stability, especially in the case of SO4 2- The main problems of ZrO2 catalysts are rapid deactivation and poor stability. Summary of the Invention

[0005] In response to the problems existing in the prior art, the purpose of the present invention is to provide a catalyst for the skeletal isomerization of normal alkanes that is both active and stable. The catalyst is insensitive to oxygen and sulfur impurities in the raw materials and has high catalytic activity and stability for the skeletal isomerization of normal alkanes at low temperatures.

[0006] To this end, the first aspect of the present invention provides a catalyst for the skeletal isomerization of normal alkanes, which comprises a ZrO2 carrier and Pt and SO4 supported thereon. 2- , and the specific surface area of ​​the catalyst is 110-130m 2 / g, and the average pore size is 5-10nm.

[0007] According to some embodiments of the present invention, based on the total mass of the catalyst, the content of the ZrO2 carrier in the catalyst is 87.5-95.5 wt%, the content of the Pt element is 1-3 wt%, and the content of the S element is 1-3 wt%.

[0008] The second aspect of the present invention provides a method for preparing the catalyst according to the first aspect of the present invention, comprising the following steps:

[0009] S1, mixing a zirconium salt solution with ammonia water for reaction, performing solid-liquid separation, washing, and drying to obtain zirconium hydroxide solid;

[0010] S2, treating the obtained zirconium hydroxide solid with a mixed solution of dilute sulfuric acid and chloroplatinic acid, and drying to obtain a catalyst precursor;

[0011] S3, immersing the obtained catalyst precursor in an ammonia solution, aging, drying, and calcining to obtain the catalyst powder.

[0012] The third aspect of the present invention provides an application of the catalyst as described in the first aspect of the present invention and / or the catalyst prepared according to the preparation method provided by the second aspect of the present invention in the skeletal isomerization reaction of normal alkanes, wherein the normal alkanes are preferably C4-C6 normal alkanes, more preferably n-butane.

[0013] According to the present invention, the catalyst is modified using the active metal Pt on the one hand, and on the other hand, a special modification method is used to use molecules with coordination functions to complex with the metal centers, thereby suppressing the aggregation of the metal during the catalyst calcination process, thereby improving the dispersion of the active centers on the catalyst surface, and ultimately obtaining a catalyst with both activity and stability. Specifically, the present invention modifies the catalyst with ammonia water, and the NH3 molecules coordinate and complex with the Pt, which can prevent the growth of Pt particles during the calcination process, thereby facilitating the uniform distribution of the Pt centers on the catalyst surface and improving the catalyst stability.

[0014] The catalyst prepared by the invention is insensitive to the content of impurities such as oxygen and sulfur in the raw materials. The prepared catalyst has high catalytic activity and stability for the skeletal isomerization of n-butane at low temperature. DETAILED DESCRIPTION

[0015] Unless otherwise indicated, the endpoints of the ranges and any values ​​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 endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0016] According to the present invention, a first aspect of the present invention provides a catalyst for the skeletal isomerization of normal alkanes, which comprises a ZrO2 carrier and Pt and SO4 supported thereon. 2- , and the specific surface area of ​​the catalyst is 110-130m 2 / g, and the average pore size is 5-10nm.

[0017] According to some embodiments of the present invention, the specific surface area of ​​the catalyst is 115m 2 / g、118m 2 / g, 120m 2 / g、123m 2 / g、125m 2 / g、128m 2 / g, 130m 2 / g and any value in between.

[0018] According to some embodiments of the present invention, the average pore size of the catalyst is 5 nm, 5.5 nm, 6 nm, 6.5 nm, 7 nm, 7.5 nm, 8 nm, 8.5 nm, 9 nm and any value therebetween.

[0019] According to some embodiments of the present invention, based on the total mass of the catalyst, the content of the ZrO2 carrier in the catalyst is 87.5-95.5 wt%, the content of the Pt element is 1-3 wt%, and the content of the S element is 1-3 wt%.

[0020] According to the present invention, "Pt loaded thereon" in the present invention only means that the carrier contains Pt elemental material, and is not intended to limit Pt to exist in the form of a metal element. The Pt can exist in the form of a element or an oxidized state, for example.

[0021] The second aspect of the present invention provides a method for preparing the catalyst according to the first aspect of the present invention, comprising the following steps:

[0022] S1, mixing a zirconium salt solution with ammonia water for reaction, performing solid-liquid separation, washing, and drying to obtain zirconium hydroxide solid;

[0023] S2, treating the obtained zirconium hydroxide solid with a mixed solution of dilute sulfuric acid and chloroplatinic acid, and drying to obtain a catalyst precursor;

[0024] S3, immersing the obtained catalyst precursor in an ammonia solution, aging, drying, and calcining to obtain the catalyst powder.

[0025] According to the present invention, the selection range of the zirconium salt is relatively wide, and it can be various existing zirconium-containing salts that can be used to prepare zirconium oxide-based solid acid catalysts, preferably at least one of zirconium oxychloride, zirconium oxynitrate and zirconium nitrate and their hydrates, and more preferably zirconium oxychloride and zirconium nitrate.

[0026] According to some embodiments of the present invention, in step S1, the amount of NH3 in the ammonia water is 4-10 times, preferably 6-8 times, the amount of zirconium salt in the zirconium salt solution.

[0027] According to some embodiments of the present invention, the concentration of the zirconium salt solution is 0.1-3.0 mol / L.

[0028] According to some embodiments of the present invention, the mass concentration of the ammonia water is 25%-28%.

[0029] According to the present invention, the method for mixing the zirconium salt solution and the ammonia water in step S1 is not specifically limited, and the mixing can be performed by a conventional mixing method that does not violate experimental common sense in the art. In some embodiments, the zirconium salt solution is added to the ammonia water for mixing.

[0030] According to some embodiments of the present invention, in step S1, the zirconium salt solution is slowly added dropwise to the vigorously stirred ammonia water.

[0031] According to some embodiments of the present invention, in step S1, the mixing reaction is carried out under constant temperature conditions.

[0032] According to some embodiments of the present invention, in step S1, the mixing reaction includes stirring for a certain period of time under constant temperature conditions.

[0033] According to some embodiments of the present invention, in step S1, the temperature of the mixing reaction is 40-100°C, preferably 60-80°C.

[0034] According to some embodiments of the present invention, in step S1, the mixing reaction time is 1-24 hours, preferably 8-16 hours.

[0035] According to some embodiments of the present invention, in step S2, the mass of the mixed solution of dilute sulfuric acid and chloroplatinic acid is 90-140% of the mass of the zirconium hydroxide solid.

[0036] According to some embodiments of the present invention, in step S2, the treatment is to immerse the zirconium hydroxide solid in a mixed solution of dilute sulfuric acid and chloroplatinic acid. In some embodiments, the immersion is performed in equal volumes. In some embodiments, the immersion time is 12-48 hours.

[0037] According to some embodiments of the present invention, in step S2, the mass fraction of H2SO4 is 3-15% based on the total mass of the mixed solution of dilute sulfuric acid and chloroplatinic acid.

[0038] According to some embodiments of the present invention, in step S2, the mass of H2SO4 in the mixed solution of dilute sulfuric acid and chloroplatinic acid is 5-15% of the mass of the zirconium hydroxide solid, for example, 5%, 8%, 10%, 13%, 15% and any value therebetween, preferably 10%-15%.

[0039] According to some embodiments of the present invention, in step S2, the amount of chloroplatinic acid in the mixed solution of dilute sulfuric acid and chloroplatinic acid is 1-2.5%, preferably 1-2%, more preferably 1-1.3% of the mass of the zirconium hydroxide solid, calculated as Pt element.

[0040] According to some embodiments of the present invention, the concentration of the ammonia solution in step S3 is 5%-30%, for example, 5%, 10%, 15%, 20%, 25%, 30% and any value therebetween, preferably 20%-30%, more preferably 20%-25%.

[0041] According to the present invention, the amount of ammonia solution added in step S3 can be selected within a wide range, as long as the catalyst precursor can be immersed therein. In some embodiments, the mass of the ammonia solution in step S3 is 90-140% of the catalyst precursor.

[0042] According to some embodiments of the present invention, the immersion temperature in step S3 can be selected in a wide range, and in some examples, the immersion is performed at room temperature.

[0043] According to some embodiments of the present invention, the immersion time in step S3 is based on the time required to allow the catalyst precursor and the ammonia solution to be fully mixed.

[0044] According to some embodiments of the present invention, the aging temperature in step S3 is 20-30° C., preferably room temperature.

[0045] According to some embodiments of the present invention, the aging time in step S3 is 1-20 days.

[0046] According to some embodiments of the present invention, in step S3, the calcination temperature is 550-700° C., for example, 550° C., 570° C., 600° C., 620° C., 650° C., 670° C., 700° C., and any value therebetween, preferably 590-650° C. In some embodiments, the calcination temperature is 620-650° C. In other embodiments, the calcination temperature is 590-620° C.

[0047] According to some embodiments of the present invention, the calcination time is 2-8 hours.

[0048] According to the present invention, the method of solid-liquid separation is not specifically limited, and conventional solid-liquid separation methods in the art such as filtration can be used as long as the solid formed in the mixed reaction can be obtained. In the present invention, the washing solvent can be water.

[0049] According to the present invention, the drying method is not specifically limited. The solvent in the obtained solid is removed, and conventional drying methods in the art, such as oven drying, can be used. In some embodiments, the drying temperature is 100-200° C., and the drying time is 5-24 hours.

[0050] According to some embodiments of the present invention, the preparation method further comprises pressing the obtained catalyst powder into tablets.

[0051] The third aspect of the present invention provides an application of the catalyst as described in the first aspect of the present invention and / or the catalyst prepared according to the preparation method provided by the second aspect of the present invention in the skeletal isomerization reaction of normal alkanes, wherein the normal alkanes are preferably C4-C6 straight-chain alkanes, more preferably n-butane.

[0052] According to some embodiments of the present invention, the normal alkane skeletal isomerization reaction is a normal alkane hydroisomerization reaction.

[0053] According to some embodiments of the present invention, the catalyst in the application requires activation treatment before use, and the activation treatment comprises heating the catalyst in a nitrogen flow containing hydrogen, preferably the nitrogen flow containing hydrogen contains 10% by volume of hydrogen.

[0054] According to some embodiments of the present invention, the activation temperature is 350-450°C.

[0055] According to some embodiments of the present invention, the activation time is 2-6 hours.

[0056] According to some embodiments of the present invention, the isomerization reaction is carried out under hydrogen conditions, wherein the molar ratio of the hydrogen to the normal alkane is (0.1-1.0):1.

[0057] According to some embodiments of the present invention, the feed mass space velocity of the normal alkane in the isomerization reaction is 0.2-3h -1 .

[0058] According to some embodiments of the present invention, the temperature of the isomerization reaction is 180-220°C.

[0059] According to some embodiments of the present invention, the pressure of the isomerization reaction is 0.5-2.0 MPa.

[0060] In the present invention, unless otherwise specified, the "concentration" refers to mass concentration.

[0061] In the present invention, unless otherwise specified, the "pressure" refers to gauge pressure.

[0062] In the present invention, unless otherwise specified, the "solution" refers to an aqueous solution of the relevant substance.

[0063] The catalyst of the present invention is insensitive to the content of impurities such as oxygen and sulfur in the raw materials. The prepared catalyst has high catalytic activity and stability for the skeletal isomerization of n-butane at low temperatures.

[0064] To make the present invention easier to understand, the present invention will be described in detail below with reference to Examples. These Examples are intended only to illustrate the present invention and should not be construed as limiting the scope of the present invention. Where specific conditions are not specified in the Examples, the methods are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the materials used in the Examples are commercially available products or conventional products that can be synthesized by known methods.

[0065] The data determination and calculation method in the embodiment of the present invention is as follows:

[0066] 1. The elemental composition of the catalyst was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) using a Wacker Varian 725ES analyzer. The sample powder was decomposed using an inorganic acid.

[0067] 2. Specific surface area and pore size distribution (BET) tests were conducted on a Tristar-3000 automated adsorption instrument manufactured by Micromeritics, Inc., USA. Samples were vacuum degassed at 350°C for 2 hours. Catalyst samples were also degassed at 350°C. Surface area was then measured in liquid nitrogen using the nitrogen adsorption capacity method, and the results were calculated using the BET method.

[0068] 3. n-Butane conversion % = (mass of n-butane in feedstock - mass of n-butane in product) / mass of n-butane in feedstock × 100%.

[0069] 4. Isobutane selectivity (%) = (mass of isobutane in the product - mass of isobutane in the feed) / (mass of normal butane in the feed - mass of normal butane in the product) × 100%.

[0070] Preparation Example 1

[0071] Take 2L of 0.5mol / L zirconium nitrate solution and slowly add it dropwise to 0.45L of vigorously stirred ammonia water (mass fraction 25-28%). After the addition is complete, stir at 90°C for 12h. The precipitate is filtered, washed with deionized water and dried to obtain 140g of zirconium hydroxide support.

[0072] Take 100g of crushed zirconium hydroxide support and immerse it in 110mL of a mixed solution of dilute sulfuric acid and chloroplatinic acid (containing 8.0g of H2SO4 and 1.55g of Pt element). After sufficient stirring, immerse it for 24h and bake it at 110℃ for 24h to obtain a catalyst precursor.

[0073] The catalyst precursor was thoroughly ground and added to 100 mL of 15% ammonia solution. After thorough stirring, the mixture was allowed to stand at room temperature for 10 days. The mixture was then dried at 110°C for 24 hours and calcined in a muffle furnace at 650°C for 4 hours. The powder was then pressed into tablets to obtain the n-butane skeletal isomerization catalyst, designated PtSZ-1. The specific surface area and pore size of the resulting catalyst are shown in Table 1.

[0074] Preparation Example 2

[0075] The preparation method was the same as that of Preparation Example 1, except that 0.8 L of a 2.0 mol / L zirconium oxychloride solution was used instead of zirconium nitrate (to obtain 200 g of zirconium hydroxide). This produced an n-butane skeletal isomerization catalyst designated PtSZ-2. The specific surface area and pore size of the resulting catalyst are shown in Table 1.

[0076] Preparation Example 3

[0077] The preparation method was the same as that of Preparation Example 1, except that the mass fraction of H₂SO₄ in the mixed solution of dilute sulfuric acid and chloroplatinic acid was 4.55%. This resulted in an n-butane skeletal isomerization catalyst designated PtSZ-3. The specific surface area and pore size of the resulting catalyst are shown in Table 1.

[0078] Preparation Example 4

[0079] The preparation method was the same as that of Preparation Example 1, except that the mass fraction of H₂SO₄ in the mixed solution of dilute sulfuric acid and chloroplatinic acid was 9.09%. This resulted in an n-butane skeletal isomerization catalyst designated PtSZ-4. The specific surface area and pore size of the resulting catalyst are shown in Table 1.

[0080] Preparation Example 5

[0081] The preparation method was the same as that of Preparation Example 1, except that the mass fraction of H₂SO₄ in the mixed solution of dilute sulfuric acid and chloroplatinic acid was 13.64%. This resulted in an n-butane skeletal isomerization catalyst designated PtSZ-5. The specific surface area and pore size of the resulting catalyst are shown in Table 1.

[0082] Preparation Example 6

[0083] The preparation method was the same as that of Preparation Example 1, except that the amount of Pt element in the mixed solution of dilute sulfuric acid and chloroplatinic acid was 1.16 g. This resulted in an n-butane skeletal isomerization catalyst designated PtSZ-6. The specific surface area and pore size of the resulting catalyst are shown in Table 1.

[0084] Preparation Example 7

[0085] The preparation method was the same as that of Preparation Example 1, except that the amount of Pt element in the mixed solution of dilute sulfuric acid and chloroplatinic acid was 1.93 g. This resulted in an n-butane skeletal isomerization catalyst designated PtSZ-7. The specific surface area and pore size of the resulting catalyst are shown in Table 1.

[0086] Preparation Example 8

[0087] The preparation method was the same as that of Preparation Example 4, except that the catalyst precursor was impregnated with 5% by mass aqueous ammonia instead of 15% by mass aqueous ammonia. This resulted in an n-butane skeletal isomerization catalyst designated PtSZ-8. The specific surface area and pore size of the resulting catalyst are shown in Table 1.

[0088] Preparation Example 9

[0089] The preparation method was the same as that of Preparation Example 4, except that the catalyst precursor was impregnated with 10% by mass ammonia aqueous solution instead of 15% by mass ammonia aqueous solution. This resulted in an n-butane skeletal isomerization catalyst designated PtSZ-9. The specific surface area and pore size of the resulting catalyst are shown in Table 1.

[0090] Preparation Example 10

[0091] The preparation method was the same as that of Preparation Example 4, except that the catalyst precursor was impregnated with 20% by mass aqueous ammonia instead of 15% by mass aqueous ammonia. This resulted in an n-butane skeletal isomerization catalyst designated PtSZ-10. The specific surface area and pore size of the resulting catalyst are shown in Table 1.

[0092] Preparation Example 11

[0093] The preparation method was the same as that of Preparation Example 4, except that the catalyst precursor was impregnated with 25% by mass aqueous ammonia instead of 15% by mass aqueous ammonia. This resulted in an n-butane skeletal isomerization catalyst designated PtSZ-11. The specific surface area and pore size of the resulting catalyst are shown in Table 1.

[0094] Preparation Example 12

[0095] The preparation method was the same as that of Preparation Example 11, except that the calcination temperature was 590°C to obtain a n-butane skeletal isomerization catalyst, designated PtSZ-12. The specific surface area and pore size of the obtained catalyst are shown in Table 1.

[0096] Preparation Example 13

[0097] The preparation method was the same as that of Preparation Example 11, except that the calcination temperature was 620°C to obtain a n-butane skeletal isomerization catalyst, designated as PtSZ-13. The specific surface area and pore size information of the obtained catalyst are shown in Table 1.

[0098] Preparation Example 14

[0099] The preparation method was the same as that of Preparation Example 11, except that the calcination temperature was 670°C to obtain a n-butane skeletal isomerization catalyst, designated as PtSZ-14. The specific surface area and pore size of the obtained catalyst are shown in Table 1.

[0100] Comparative Example 1

[0101] The preparation method was the same as that of Preparation Example 1, except that the catalyst precursor was directly calcined without being impregnated with aqueous ammonia solution, resulting in an n-butane skeletal isomerization catalyst designated PtSZ-C1. The specific surface area and pore size of the resulting catalyst are shown in Table 1.

[0102] Example

[0103] The performance of the n-butane skeletal isomerization catalysts prepared in Preparation Examples 1-14 and Comparative Example 1 was evaluated in a fixed-bed continuous flow reactor system. The reactor was 5 mm × 40 cm in size, with a catalyst loading of 10 mL and a particle size of 20-40 mesh, placed in the constant temperature zone of the furnace. The reaction temperature was 180°C, the hydrogen pressure was 1 MPa, and the n-butane mass space velocity was 0.5 h-1. -1 The molar ratio of hydrogen to n-butane was 1:1, and the reaction products were analyzed online by gas chromatography. The results are shown in Table 2.

[0104] Table 1

[0105] Catalyst <![CDATA[Specific surface area / m 2 .g -1 > Average pore diameter / nm PtSZ-1 114 8.1 PtSZ-2 113 9.0 PtSZ-3 112 8.8 PtSZ-4 117 7.7 PtSZ-5 113 7.0 PtSZ-6 114 9.3 PtSZ-7 119 7.1 PtSZ-8 112 8.3 PtSZ-9 115 8.5 PtSZ-10 116 8.6 PtSZ-11 114 8.2 PtSZ-12 129 5.0 PtSZ-13 124 7.3 PtSZ-14 108 9.1 PtSZ-C1 101 8.4

[0106] Table 2

[0107]

[0108]

[0109] It can be seen from Table 1 that after the catalyst precursor is treated with ammonia water, the prepared catalyst has a larger specific surface area.

[0110] As shown in Table 2, when the catalyst support was not impregnated with ammonia solution, the n-butane conversion decreased from 52.2% to 43.0%, and the isobutane selectivity decreased from 85.2% to 83.0% after the catalyst was evaluated for ten days. However, after the catalyst was modified with ammonia solution, the catalyst activity and product selectivity decreased less, which shows that the use of ammonia solution treatment effectively improved the stability of the catalyst.

[0111] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A catalyst for the skeletal isomerization of normal alkanes, comprising a ZrO2 carrier and Pt and SO4 supported thereon 2- , and the specific surface area of ​​the catalyst is 110-130m 2 / g, average pore size is 5-10nm, The preparation method of the catalyst comprises the following steps: S1, mixing a zirconium salt solution with ammonia water for reaction, performing solid-liquid separation, washing, and drying to obtain zirconium hydroxide solid; S2, treating the obtained zirconium hydroxide solid with a mixed solution of dilute sulfuric acid and chloroplatinic acid, and drying to obtain a catalyst precursor; S3, immersing the obtained catalyst precursor in an ammonia solution, aging, drying, and calcining to obtain the catalyst powder.

2. The catalyst according to claim 1, characterized in that Based on the total mass of the catalyst, the content of the ZrO2 carrier in the catalyst is 87.5-95.5wt%, the content of the Pt element is 1-3wt%, and the content of the S element is 1-3wt%.

3. The method for preparing the catalyst according to claim 1 or 2, comprising the steps of: S1, mixing a zirconium salt solution with ammonia water for reaction, performing solid-liquid separation, washing, and drying to obtain zirconium hydroxide solid; S2, treating the obtained zirconium hydroxide solid with a mixed solution of dilute sulfuric acid and chloroplatinic acid, and drying to obtain a catalyst precursor; S3, immersing the obtained catalyst precursor in an ammonia solution, aging, drying, and calcining to obtain the catalyst powder.

4. The preparation method according to claim 3, characterized in that The zirconium salt is selected from at least one of zirconium nitrate, zirconium oxychloride, zirconium oxynitrate and hydrates thereof.

5. The preparation method according to claim 3, characterized in that In step S1, the amount of NH3 in the ammonia water is 4-10 times the amount of zirconium salt in the zirconium salt solution.

6. The preparation method according to claim 5, characterized in that In step S1, the amount of NH3 in the ammonia water is 6-8 times the amount of zirconium salt in the zirconium salt solution.

7. The preparation method according to claim 3, characterized in that The concentration of the zirconium salt solution is 0.1-3.0 mol / L, and / or the mass concentration of the ammonia water is 25%-28%.

8. The preparation method according to any one of claims 3 to 7, characterized in that In step S1, the mixing reaction is carried out under a constant temperature condition, the temperature of the mixing reaction is 40-100° C.; and / or the time of the mixing reaction is 1-24 hours.

9. The preparation method according to claim 8, characterized in that In step S1, the temperature of the mixing reaction is 60-80° C.; and / or the time of the mixing reaction is 8-16 hours.

10. The preparation method according to any one of claims 3 to 7, characterized in that: In step S2, the mass of the mixed solution of dilute sulfuric acid and chloroplatinic acid is 90-140% of the mass of the zirconium hydroxide solid.

11. The preparation method according to claim 10, characterized in that: Based on the total mass of the mixed solution of dilute sulfuric acid and chloroplatinic acid, the mass fraction of H2SO4 is 3-15%, and / or the amount of chloroplatinic acid used is 1-2.5% of the mass of the zirconium hydroxide solid calculated as Pt element.

12. The preparation method according to any one of claims 3 to 7, characterized in that: In step S2, the treatment is to immerse the zirconium hydroxide solid in a mixed solution of dilute sulfuric acid and chloroplatinic acid, and the immersion time is 12-48 hours.

13. The preparation method according to any one of claims 3 to 7, characterized in that: The concentration of the ammonia solution in step S3 is 5-25%, and / or the aging temperature is 20-30° C., and the aging time is 1-20 days.

14. The preparation method according to claim 13, characterized in that The concentration of the ammonia solution in step S3 is 20-30%.

15. The preparation method according to any one of claims 3 to 7, characterized in that: The calcination temperature in step S3 is 550-700° C., and / or the calcination time is 2-8 hours.

16. Use of the catalyst according to claim 1 or 2 and / or the catalyst prepared by the preparation method according to any one of claims 3 to 15 in the skeletal isomerization reaction of normal alkanes.

17. The use according to claim 16, characterized in that The normal alkane is a C4-C6 straight-chain alkane.

18. The use according to claim 17, characterized in that The normal alkane is normal butane.

19. The use according to claim 16, characterized in that In the application, the catalyst needs to be activated before use. The activation treatment includes heating the catalyst in a nitrogen flow containing hydrogen.

20. The use according to claim 19, characterized in that The hydrogen-containing nitrogen flow contains 10% by volume of hydrogen.

21. The use according to claim 19, characterized in that The activation temperature is 350-450° C., and / or the activation time is 2-6 hours.

22. The use according to any one of claims 16 to 21, characterized in that The isomerization reaction is carried out under hydrogen conditions, wherein the molar ratio of hydrogen to the normal alkane is (0.1-1.0):

1.

23. The use according to claim 22, characterized in that The feed mass space velocity of the normal alkane is 0.2-3h -1 .

24. The use according to claim 22, characterized in that The temperature of the isomerization reaction is 180-220° C., and / or the pressure of the isomerization reaction is 0.5-2.0 MPa.

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