Catalyst for inhibiting dehydrogenation isomerization of n-butane as well as preparation method and application of catalyst

Abstract

The invention discloses a catalyst for inhibiting dehydrogenation isomerization of n-butane as well as a preparation method and application of the catalyst, and belongs to the technical field of catalysts. The catalyst for inhibiting dehydrogenation isomerization of n-butane comprises a carrier, a platinum element and indium oxide, the platinum element and the indium oxide are loaded on the carrier, the mass percentage of the platinum element in the catalyst is at least 0.05 wt%, and the mass percentage of the indium element in the catalyst is 0.5-8 wt%. According to the catalyst for inhibiting the dehydrogenation isomerization of the n-butane, through the synergistic effect of the platinum elementary substance and the indium oxide loaded on the carrier, in the dehydrogenation reaction of the n-butane, the conversion efficiency of the n-butane is improved, the side reaction of the dehydrogenation isomerization of the n-butane is inhibited, and the selectivity of a byproduct isobutene is reduced; therefore, the selectivity of the target product butadiene is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and more specifically, to a catalyst for inhibiting dehydrogenation isomerization of n-butane, and a preparation method and application thereof. Background Art

[0002] Butadiene is a key raw material in the chemical industry and is widely used in the production of rubber, plastic and other products. With the rapid development of the economy and society, the demand for butadiene has increased year by year. Traditionally, butadiene is produced by naphtha cracking. However, affected by the global energy crisis, the traditional butadiene production process route faces severe challenges. Therefore, it is urgent to develop a new butadiene production process with lower cost and higher production efficiency. In recent years, with the breakthrough of shale gas exploration and mining technology, the process of preparing butadiene by direct dehydrogenation of n-butane, which is rich in shale gas, has received more and more attention.

[0003] The direct dehydrogenation of n-butane is an equilibrium-limited endothermic reaction that requires high temperatures (550-700°C) to achieve actual conversion. Platinum-based catalysts are one of the most widely used industrial catalysts in the alkane dehydrogenation process. However, under high-temperature reaction conditions, platinum is prone to sintering, carbon deposition and other problems that lead to catalyst deactivation, limiting the practical application of the catalyst. In addition, the n-butane dehydrogenation reaction will inevitably lead to side reactions such as over-dehydrogenation and dehydrogenation isomerization, thereby forming various C1-C4 products, such as methane, ethylene, propylene, isobutylene, etc. Therefore, the development of catalysts with high stability, high activity and high olefin selectivity is very important for the process of n-butane dehydrogenation to prepare butadiene.

[0004] The prior art enhances the anti-sintering and anti-coke deposition capabilities of platinum-based catalysts by introducing gallium oxide metal promoters into platinum-based alkane dehydrogenation catalysts. The selectivity of total C4 olefins such as n-butene, isobutylene, cis-2-butene, trans-2-butene and butadiene in the product of n-butane dehydrogenation catalyzed by this catalyst can exceed 85%. N-butene, cis-2-butene and trans-2-butene can be further dehydrogenated to butadiene, but the isobutylene formed by the dehydrogenation isomerization of n-butane cannot be further dehydrogenated to butadiene. In the existing catalysts, the selectivity of isobutylene can exceed 15%, which greatly reduces the selectivity of butadiene. Therefore, it is particularly important to inhibit the occurrence of n-butane dehydrogenation isomerization side reactions. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of a high degree of dehydrogenation isomerization side reaction in the existing n-butane dehydrogenation reaction process, such that the selectivity of the by-product isobutylene is high but the selectivity of the target product butadiene is too low, and to provide a catalyst for inhibiting the dehydrogenation isomerization of n-butane. Through the synergistic effect of a single platinum substance and indium oxide loaded on a carrier, in the n-butane dehydrogenation reaction, the conversion efficiency of n-butane is improved, the occurrence of the n-butane dehydrogenation isomerization side reaction is inhibited, the selectivity of the by-product isobutylene is reduced, and thus the selectivity of the target product butadiene is improved.

[0006] Another object of the present invention is to provide a method for preparing a catalyst for inhibiting dehydrogenation isomerization of n-butane.

[0007] Another object of the present invention is to provide a method for catalyzing the dehydrogenation of n-butane to prepare butadiene.

[0008] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0009] A catalyst for inhibiting dehydrogenation isomerization of normal butane comprises a carrier, a platinum element and indium oxide loaded on the carrier, wherein the mass percentage of the platinum element in the catalyst is at least 0.05wt%, and the mass percentage of the indium element in the catalyst is 0.5-8wt%.

[0010] The catalyst for inhibiting the dehydrogenation isomerization of n-butane of the present invention has excellent conversion efficiency of n-butane through the synergistic effect of the platinum element and indium oxide loaded on the carrier, and can inhibit excessive cracking of n-butane, inhibit the occurrence of n-butane dehydrogenation isomerization side reactions, reduce the selectivity of the by-product isobutylene, and thus improve the selectivity of the target product butadiene.

[0011] The n-butane conversion efficiency is the average reaction rate, which is the molar amount of n-butane converted per gram of platinum in the catalyst per minute, reflecting the speed of the reaction.

[0012] If the mass percentage of indium is too high, the conversion efficiency of n-butane will be reduced. This may be because indium oxide will cover some of the reactive sites of platinum. Therefore, the indium content cannot be too high.

[0013] Optionally, the mass percentage of indium element in the catalyst is 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, or 8wt%.

[0014] Preferably, the mass percentage of indium element in the catalyst is 2-6wt%.

[0015] The mass percentage of indium element in the catalyst is 2-6wt%, and the conversion efficiency of n-butane is higher.

[0016] Preferably, the mass percentage of platinum in the catalyst is 0.05-0.1 wt%.

[0017] The mass percentage of platinum in the catalyst of the present invention is relatively high, which can significantly improve the conversion rate of n-butane. However, due to the high price of platinum, the present invention can also achieve a higher n-butane conversion rate, n-butane conversion efficiency and a higher selectivity of the target product butadiene through the synergistic effect of a lower platinum content and indium oxide.

[0018] More preferably, the mass percentage of platinum in the catalyst is 0.05-0.08 wt %.

[0019] Optionally, the mass percentage of platinum in the catalyst is 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, or 0.1wt%.

[0020] Preferably, the carrier is composed of silicon oxide and aluminum oxide, and the mass ratio of silicon oxide to aluminum oxide is (0.5-1.5):9.

[0021] More preferably, the carrier is composed of silicon oxide and aluminum oxide, and the mass ratio of silicon oxide to aluminum oxide is 1:9.

[0022] In the present invention, the carrier is silicon-aluminum oxide, and the mass ratio of silicon oxide to aluminum oxide is 1: 9. Indium oxide can neutralize the acid sites on the carrier, which is beneficial to inhibiting the occurrence of the n-butane dehydrogenation isomerization side reaction.

[0023] The present invention also protects a method for preparing the catalyst for inhibiting the dehydrogenation isomerization of n-butane as described in any one of the above items, comprising the following steps:

[0024] S1. The indium hydroxide and chloroplatinate aqueous solution are heated, mixed, and calcined to obtain product A;

[0025] S2. mixing product A with a carrier to obtain product B;

[0026] S3. Calcine and reduce the product B to obtain a catalyst for inhibiting the dehydrogenation isomerization of n-butane.

[0027] In actual operation, indium hydroxide can be obtained from the market or prepared at home.

[0028] For example, the preparation method of indium hydroxide is as follows: an aqueous solution of indium nitrate is added to an aqueous solution of sodium hydroxide, and after magnetic stirring, the mixture is transferred to a 100 mL stainless steel reactor lined with polytetrafluoroethylene, placed in an oven, reacted at 120°C for 24 hours, and then naturally cooled to room temperature. The obtained solid sample is then washed with deionized water by centrifugation, and then dried to obtain a white powder product of indium hydroxide.

[0029] The chloroplatinate may be potassium chloroplatinate.

[0030] Preferably, in step S1, the heating temperature is 60-80°C, the calcination temperature is 500-600°C, and the calcination time is 1-3 hours.

[0031] Preferably, in step S2, product A can be dispersed in deionized water, mixed with a carrier after ultrasonic dispersion, stirred at 60-80° C. to a slurry, then transferred to an oven for drying, and ground to obtain a powdered product B.

[0032] Preferably, in step S3, the calcination temperature is 500-650° C., and the calcination time is 1-3 hours.

[0033] Preferably, in step S3, the reduction temperature is a mixture of hydrogen and argon, the volume percentage of hydrogen in the mixture is 5%, the reduction temperature is 500-600° C., and the reduction time is 10-40 min.

[0034] The present invention also protects a method for catalytically dehydrogenating n-butane to produce butadiene, comprising the following steps: contacting an n-butane raw material with a catalyst for reaction, wherein the products include butadiene and isobutylene; and the catalyst is any of the above-mentioned catalysts for inhibiting the dehydrogenation isomerization of n-butane.

[0035] Preferably, the reaction pressure is 0.1 MPa, the reaction temperature is 525-625°C, the feed volume ratio of n-butane and nitrogen is 5:50, and the space velocity is 16500 mL / g cat / h.

[0036] In actual operation, the n-butane dehydrogenation performance is usually evaluated in a vertical quartz fixed bed reactor.

[0037] Preferably, the conversion rate of n-butane is greater than 20%, the selectivity of butadiene is greater than 19%, and the selectivity of isobutylene is less than 6%.

[0038] The present invention also protects a method for regenerating the catalyst for inhibiting the dehydrogenation isomerization of n-butane, comprising the following steps: calcining the catalyst for inhibiting the dehydrogenation isomerization of n-butane described in any one of the above items in an air atmosphere, the calcination temperature is 750° C., and the calcination time is 5 to 30 minutes.

[0039] If the calcination temperature is too high, the catalyst will easily lose its activity.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The invention discloses a catalyst for inhibiting the dehydrogenation isomerization of n-butane. Through the synergistic effect of a single platinum substance and indium oxide loaded on a carrier, the n-butane conversion efficiency is high, the excessive cracking of n-butane can be inhibited, and the occurrence of a n-butane dehydrogenation isomerization side reaction can be inhibited, the selectivity of the product isobutylene is reduced, and thus the selectivity of butadiene is improved.

[0042] The catalyst for inhibiting the dehydrogenation isomerization of n-butane of the present invention has a 0.45 mol / g Pt / min or more, the n-butane conversion efficiency is more than 20%, the n-butane conversion rate is more than 20%, the selectivity of C1-C3 in the gas product can be as low as below 16.26%, the selectivity of total C4 olefins in the gas product can exceed 83%, and the selectivity of isobutylene in the gas product can be as low as below 5.46%. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is the X-ray photoelectron spectrum of the catalyst in Example 1.

[0044] Figure 2 a is a morphology image of the catalyst of Example 1 taken under a high-angle annular dark field image scanning transmission electron microscope, Figure 2 b~ Figure 2 f is the elemental EDS spectrum of the catalyst in Example 1.

[0045] Figure 3 This is a stability test chart of the catalyst in Example 1 after 100 cycles. DETAILED DESCRIPTION

[0046] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0047] The mass fractions of platinum and indium in the catalysts were measured by inductively coupled plasma optical emission spectroscopy (ICP-QES).

[0048] The carrier is silicon-aluminum oxide SIRAL10, the mass ratio of silicon oxide to aluminum oxide is 1:9, and it is provided by SASOL.

[0049] Example 1

[0050] A catalyst for inhibiting dehydrogenation isomerization of n-butane, comprising a carrier, a platinum element and indium oxide loaded on the carrier, wherein the mass percentage of the platinum element in the catalyst is 0.06wt%, and the mass percentage of the indium element in the catalyst is 4.43wt%;

[0051] The carrier is composed of silicon oxide and aluminum oxide, and the mass ratio of silicon oxide to aluminum oxide is 1:9.

[0052] The preparation method of the catalyst for inhibiting the dehydrogenation isomerization of n-butane comprises the following steps:

[0053] Preparation of indium hydroxide: 5 mL of 0.003 mol / L indium nitrate aqueous solution was added to 75 mL of 0.009 mol / L sodium hydroxide aqueous solution, and the mixture was transferred to a 100 mL stainless steel reactor lined with polytetrafluoroethylene after magnetic stirring for 20 minutes, placed in an oven, reacted at 120°C for 24 hours, and then naturally cooled to room temperature. The obtained solid sample was then washed three times with deionized water by centrifugation, and dried in an oven at 80°C overnight to obtain a white powder product, indium hydroxide.

[0054] S1. Weigh 144 mg of indium hydroxide powder, add 1.285 mL of 0.01 mol / L potassium chloroplatinate aqueous solution dropwise to the indium hydroxide powder, stir at 60°C for 4 h, dry in an oven at 80°C for 12 h, transfer to a muffle furnace, and calcine at 500°C in an air atmosphere for 2 h to obtain product A.

[0055] S2. Product A was dispersed in 4 mL of deionized water, and after ultrasonic treatment for 30 min, 2 g of carrier was added and mixed. The mixture was stirred continuously at 60 °C until it became a slurry. The mixture was transferred to an oven at 80 °C and dried for 12 h. The powdered product B was obtained after grinding.

[0056] S3. The product B powder was placed in a muffle furnace, calcined in an air atmosphere at 600°C for 2 hours, then taken out, placed in a tubular furnace, and reduced with a hydrogen-argon mixture (5% H2 / Ar) at 575°C for 30 minutes to obtain a catalyst for inhibiting the dehydrogenation isomerization of n-butane.

[0057] Example 2

[0058] A catalyst for inhibiting dehydrogenation isomerization of n-butane, comprising a carrier, a platinum element and indium oxide loaded on the carrier, wherein the mass percentage of the platinum element in the catalyst is 0.05wt%, and the mass percentage of the indium element in the catalyst is 0.79wt%;

[0059] The carrier is composed of silicon oxide and aluminum oxide, and the mass ratio of silicon oxide to aluminum oxide is 1:9.

[0060] The difference between the preparation method and Example 1 is that the amount of indium hydroxide powder is 28.8 mg.

[0061] Example 3

[0062] A catalyst for inhibiting dehydrogenation isomerization of n-butane, comprising a carrier, a platinum element and indium oxide loaded on the carrier, wherein the mass percentage of the platinum element in the catalyst is 0.05wt%, and the mass percentage of the indium element in the catalyst is 2.47wt%;

[0063] The carrier is composed of silicon oxide and aluminum oxide, and the mass ratio of silicon oxide to aluminum oxide is 1:9.

[0064] The difference between the preparation method and Example 1 is that the amount of indium hydroxide powder is 86.4 mg.

[0065] Example 4

[0066] A catalyst for inhibiting dehydrogenation isomerization of n-butane, comprising a carrier, a platinum element and indium oxide loaded on the carrier, wherein the mass percentage of the platinum element in the catalyst is 0.07wt%, and the mass percentage of the indium element in the catalyst is 5.22wt%;

[0067] The carrier is composed of silicon oxide and aluminum oxide, and the mass ratio of silicon oxide to aluminum oxide is 1:9.

[0068] The difference between the preparation method and Example 1 is that the amount of indium hydroxide powder is 187 mg.

[0069] Example 5

[0070] A catalyst for inhibiting dehydrogenation isomerization of n-butane, comprising a carrier, a platinum element and indium oxide loaded on the carrier, wherein the mass percentage of the platinum element in the catalyst is 0.07wt%, and the mass percentage of the indium element in the catalyst is 6.77wt%;

[0071] The carrier is composed of silicon oxide and aluminum oxide, and the mass ratio of silicon oxide to aluminum oxide is 1:9.

[0072] The difference between the preparation method and Example 1 is that the amount of indium hydroxide powder is 230.4 mg.

[0073] Comparative Example 1

[0074] A n-butane dehydrogenation catalyst comprises a carrier and a platinum element loaded on the carrier, wherein the mass percentage of the platinum element in the catalyst is 0.08wt%;

[0075] The carrier is composed of silicon oxide and aluminum oxide, and the mass ratio of silicon oxide to aluminum oxide is 1:9.

[0076] The preparation method of the above-mentioned n-butane dehydrogenation catalyst comprises the following steps:

[0077] S1. Mix 1.285 mL of 0.01 mol / L potassium chloroplatinate aqueous solution with 3 mL of deionized water and perform ultrasonic treatment for 30 min to form a uniform solution A.

[0078] S2. The above solution was added dropwise to 2 g of the carrier, and the mixture was stirred continuously at 60°C until it became a slurry. The mixture was transferred to an oven at 80°C and dried for 12 h. The powdered product B was obtained after grinding.

[0079] S3. The product B powder was placed in a muffle furnace, calcined in an air atmosphere at 600°C for 2 hours, then taken out, placed in a tubular furnace, and reduced with a hydrogen-argon mixture (5% H2 / Ar) at 575°C for 30 minutes to obtain an n-butane dehydrogenation catalyst.

[0080] Comparative Example 2

[0081] A n-butane dehydrogenation catalyst comprises a carrier and indium oxide loaded on the carrier, wherein the mass percentage of indium element in the catalyst is 3.74wt%;

[0082] The carrier is composed of silicon oxide and aluminum oxide, and the mass ratio of silicon oxide to aluminum oxide is 1:9.

[0083] S1. Weigh 115 mg of indium hydroxide powder and calcine it in an air atmosphere at 500° C. for 2 h to obtain product A.

[0084] S2. Product A was dispersed in 4 mL of deionized water, and after ultrasonic treatment for 30 min, 2 g of carrier was added and mixed. The mixture was stirred continuously at 60 °C until it became a slurry. The mixture was transferred to an oven at 80 °C and dried for 12 h. The powdered product B was obtained after grinding.

[0085] S3. The product B powder was placed in a muffle furnace, calcined in an air atmosphere at 600°C for 2 hours, then taken out, placed in a tubular furnace, and reduced with a hydrogen-argon mixture (5% H2 / Ar) at 575°C for 30 minutes to obtain an n-butane dehydrogenation catalyst.

[0086] Comparative Example 3

[0087] A n-butane dehydrogenation catalyst comprises a carrier, a platinum element supported on the carrier and gallium oxide, wherein the mass percentage of the platinum element in the catalyst is 0.08wt%, and the mass percentage of the gallium element in the catalyst is 4.76wt%;

[0088] The carrier is composed of silicon oxide and aluminum oxide, and the mass ratio of silicon oxide to aluminum oxide is 1:9.

[0089] The preparation method of the above-mentioned n-butane dehydrogenation catalyst comprises the following steps:

[0090] (1) Weigh 366.8 mg of gallium nitrate and dissolve it in 3 mL of deionized water. Add 1.285 mL of a 0.01 mol / L potassium chloroplatinate aqueous solution and perform ultrasonic treatment for 30 min to form a uniform solution A.

[0091] (2) The above solution was added dropwise to 2 g of the carrier and stirred continuously at 60°C until it became a slurry. The mixture was then transferred to an oven at 80°C and dried for 12 h. The powdered product B was obtained after grinding.

[0092] (3) The product B powder was placed in a muffle furnace and calcined in an air atmosphere at 600° C. for 2 h. It was then taken out and placed in a tubular furnace and reduced with a hydrogen-argon mixture (5% H2 / Ar) at 575° C. for 30 min to obtain an n-butane dehydrogenation catalyst.

[0093] Results

[0094] (1) The catalyst of Example 1 was subjected to XPS characterization to analyze the chemical structure characteristics of the catalyst surface. The results are as follows: Figure 1 shown. Figure 1 a is the In 3d spectrum. The two strong peaks observed are located at 444.2 and 451.8 eV, which are In 3+ The typical peaks of , indicating that the indium element in the catalyst exists in the form of indium oxide on the surface of the carrier. Figure 1 b is the Pt 4d spectrum, the peaks at 312.2 and 329.8 eV correspond to Pt 0 , indicating that the platinum element in the catalyst exists in metallic state.

[0095] (2) Take the catalyst of Example 1 and analyze the morphology and elemental composition of the catalyst using HAADF-STEM and EDS-mapping to obtain an image such as Figure 2 shown.

[0096] Figure 2 a is a photo of the catalyst morphology taken under a high-angle annular dark-field image scanning transmission electron microscope. A large number of bright spots corresponding to platinum nanoparticles are observed in the image. Figure 2 bf are elemental maps, indicating that Pt and In2O3 were successfully loaded on the carrier.

[0097] (3) n-Butane dehydrogenation performance test:

[0098] The performance of n-butane dehydrogenation was evaluated in a vertical quartz fixed bed reactor with an inner diameter of 8 mm. The total pressure was set to 0.1 MPa, the reaction temperature was 575 °C, the reaction gas composition was n-butane: nitrogen = 5:50 mL / min, and the space velocity was 16500 mL / g cat / h. Usually, 0.2g of catalyst (60-80 mesh) is diluted with 0.6g of quartz sand (60-80 mesh) and mixed and loaded into a quartz reactor. A mass flow controller is used to control the gas flow rate. In this experiment, the content of each gas component is detected and analyzed online by two gas chromatographs (Zhejiang Fuli Analytical Instrument Co., Ltd.). The two gas chromatographs are equipped with a hydrogen flame ionization detector (FID) and a thermal conductivity detector (TCD), respectively. During the reaction, n-butane, butadiene, n-butene, isobutylene, cis-2-butene, trans-2-butene and C1-C3 hydrocarbons are detected by a gas chromatograph equipped with an FID detector; hydrogen and nitrogen are detected by a gas chromatograph equipped with a thermal conductivity detector. Calculate the conversion efficiency of n-butane, the conversion rate of n-butane and the selectivity of gas products.

[0099] The conversion efficiency of n-butane is the average reaction rate, which is the molar amount of n-butane converted per gram of platinum in the catalyst per minute.

[0100] The following test data is for a reaction time of 10 minutes.

[0101] The test results are shown in Table 1:

[0102] Table 1. Performance of n-butane dehydrogenation of catalysts in various embodiments and comparative examples

[0103]

[0104] It can be seen from the above results that the catalyst for inhibiting the dehydrogenation isomerization of n-butane in the embodiment of the present invention has a catalyst content of 0.45 to 0.84 mol / g Pt / min or more, with an n-butane conversion efficiency of 20% to 45.28%, and a C1-C3 selectivity in the gas product as low as 16.26% or less, indicating that the catalyst for inhibiting the dehydrogenation and isomerization of n-butane of the present invention can inhibit excessive cracking of n-butane. Moreover, the selectivity of total C4 olefins in the gas product can exceed 83%, and the selectivity of isobutylene in the gas product can be as low as 5.46% or less, indicating that the catalyst for inhibiting the dehydrogenation and isomerization of n-butane of the present invention can inhibit the occurrence of the dehydrogenation and isomerization side reaction of n-butane, which is beneficial to improving the selectivity of butadiene, and the selectivity of butadiene can be as high as 19.43% to 21.97%.

[0105] It can be seen from the examples and comparative example 1 that the n-butane dehydrogenation catalyst does not contain indium oxide but only contains platinum, the conversion rate of n-butane is too low, and the selectivity of C1-C3 in the gas product is as high as 60%, which indicates that most of the n-butane is over-cracked and the selectivity of the target product butadiene is too low to meet the requirements.

[0106] It can be seen from the example and comparative example 2 that the n-butane dehydrogenation catalyst contains only indium oxide and no platinum element, the conversion rate of n-butane is too low, and the selectivity of C1-C3 in the gas product is too high, which cannot meet the requirements.

[0107] It can be seen from the examples and comparative example 3 that although the use of platinum and gallium oxide as active components of the catalyst improves the conversion rate of n-butane and the selectivity of total C4 olefins can exceed 85%, the selectivity of isobutylene will exceed 15%, which cannot meet the requirements because isobutylene cannot be further degraded into butadiene.

[0108] It can be seen from the examples that the catalyst of Example 1 has excellent n-butane conversion efficiency, n-butane conversion rate and excellent butadiene selectivity. Therefore, the catalyst of Example 1 has the best catalytic effect.

[0109] (4) n-Butane dehydrogenation test catalyst cycle stability

[0110] The used catalyst Example 1 was regenerated and then tested for n-butane dehydrogenation to evaluate the long-term stability of the catalyst Example 1 for n-butane dehydrogenation in 100 consecutive cycles. The test results are as follows: Figure 3 shown.

[0111] Regeneration treatment method: The catalyst of Example 1 after reaction was calcined at 750° C. in air atmosphere for 15 min.

[0112] In Example 1, during 100 consecutive cycles, the conversion rate of n-butane was 35% to 45%, the selectivity of butadiene was close to 20%, the selectivity of isobutylene was always less than 2%, and the total C4 olefin selectivity was higher than 90%, indicating that Example 1 still maintained a high activity after repeated high-temperature regeneration.

[0113] Figure 3 The results show that after the catalyst of Example 1 is regenerated, its performance is stable in 100 consecutive cycle tests and it can be reused.

[0114] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A catalyst for inhibiting the dehydrogenation isomerization of n-butane, characterized in that: The catalyst comprises a carrier, a platinum element and indium oxide loaded on the carrier, wherein the mass percentage of the platinum element in the catalyst is at least 0.05wt%, and the mass percentage of the indium element in the catalyst is 0.5-8wt%.

2. The catalyst for inhibiting the dehydrogenation isomerization of n-butane according to claim 1, characterized in that: The mass percentage of indium element in the catalyst is 2-6wt%.

3. The catalyst for inhibiting the dehydrogenation isomerization of n-butane according to claim 1, characterized in that: The mass percentage of platinum in the catalyst is 0.05-0.08wt%.

4. The catalyst for inhibiting the dehydrogenation isomerization of n-butane according to claim 1, characterized in that: The carrier is composed of silicon oxide and aluminum oxide, and the mass ratio of silicon oxide to aluminum oxide is (0.5-1.5):

9.

5. The method for preparing the catalyst for inhibiting dehydrogenation isomerization of n-butane according to any one of claims 1 to 4, characterized in that: The steps include: S1. The indium hydroxide and chloroplatinate aqueous solution are heated, mixed, and calcined to obtain product A; S2. mixing product A with a carrier to obtain product B; S3. Calcine and reduce the product B to obtain a catalyst for inhibiting the dehydrogenation isomerization of n-butane.

6. The method for preparing a catalyst for inhibiting dehydrogenation isomerization of n-butane as claimed in claim 5, characterized in that: In step S1, the heating temperature is 60-80°C, the calcination temperature is 500-600°C, and the calcination time is 1-3h.

7. The method for preparing a catalyst for inhibiting dehydrogenation isomerization of n-butane as claimed in claim 5, characterized in that: In step S3, the calcination temperature is 500-650°C, the calcination time is 1-3h, the reduction temperature is 500-600°C, and the reduction time is 10-40min.

8. A method for preparing butadiene by catalytic dehydrogenation of n-butane, characterized in that: The method comprises the following steps: contacting an n-butane raw material with a catalyst for reaction, and the products include butadiene and isobutylene; the catalyst is the catalyst for inhibiting the dehydrogenation isomerization of n-butane as claimed in any one of claims 1 to 4.

9. The method for preparing butadiene by catalytic dehydrogenation of n-butane as claimed in claim 8, characterized in that: The reaction pressure is 0.1MPa, the reaction temperature is 525-625℃, the feed volume ratio of n-butane and nitrogen is 5:50, and the space velocity is 16500mL / g cat / h.

10. A method for regenerating a catalyst for inhibiting the dehydrogenation isomerization of n-butane, comprising the following steps: calcining the catalyst for inhibiting the dehydrogenation isomerization of n-butane according to any one of claims 1 to 4 in an air atmosphere at a calcination temperature of 750°C for a calcination time of 5 to 30 minutes.

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