Normalized catalyst as well as preparation method and application thereof

Abstract

The invention discloses a normalized catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) surface treatment of a molecular sieve: treating the molecular sieve in a plasma atmosphere; (2) active component loading: uniformly mixing a precursor solution containing an active component with the material obtained in the step (1), and then carrying out aging treatment; and (3) crystallization treatment: uniformly mixing the material obtained in the step (2), water and a template agent, carrying out crystallization treatment, and then carrying out washing, drying and heat treatment to obtain the normalized catalyst. The catalyst has good carbon deposition resistance and good stability, and the preparation method of the catalyst is simple and easy to implement.

Description

Technical Field

[0001] The present invention relates to a catalytic material and a preparation method thereof, and particularly to a n - isomerization catalyst, a preparation method thereof and an application thereof. Background Art

[0002] n - Butane is a common hydrocarbon substance, which is a colorless and easily liquefied gas under normal temperature and pressure. As an important chemical raw material, n - butane can be directly used as fuel, and can also be used as a sub - critical biotechnology extraction solvent and refrigerant. In addition, butane can also be used to produce chemicals such as butene, butadiene, maleic anhydride, acetic acid, acetaldehyde, halogenated butane, nitro - butane, etc. in the presence of a catalyst.

[0003] At present, the main production method of n - butane in China is to physically separate and purify the mixed C4 components in natural gas, refinery gas and cracked gas generated in the petroleum refining process to obtain n - butane. However, this method will inevitably produce a large amount of by - products such as isobutane, greatly increasing the storage and transportation costs of enterprises and seriously affecting the economic benefits of enterprises. Therefore, it is of great significance to develop a more economical and efficient production method of n - butane. Among them, the preparation of high - purity n - butane by the isomerization reaction of isobutane under the action of a catalyst has become a research hotspot.

[0004] CN104892339A proposes a method for hydrogenating isobutane to produce n - butane. Isobutane is first converted into n - butane in a n - isomerization reactor, then enters a hydrogenation saturation reactor to remove the olefins generated by the n - isomerization reaction, and finally n - butane pure product is obtained after separation. The isomerization of isobutane reacts to produce n - butane on a traditional metal chloride oxide catalyst at 500 °C and 3.0 MPa.

[0005] CN108530254A proposes a method for preparing n - butane from mixed C4. After the mixed C4 components are desulfurized and then separated through an extraction column, n - butane is separated from the bottom of the column, and isobutane is collected in the middle of the column. The collected isobutane is subjected to an isomerization reaction under the action of a catalyst to produce n - butane. The isomerization of isobutane is carried out on a chlorine - containing catalyst loaded with one or more metals, and its reaction temperature > 400 °C and reaction pressure > 2.5 MPa, which has problems such as equipment corrosion, environmental pollution and high reaction energy consumption.

[0006] The n - isomerization catalysts in the above patents are traditional metal chloride oxide catalysts or chlorine - containing catalysts loaded with one or more metals, and the performance of the catalysts needs to be further improved. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the present invention provides a n - hexane isomerization catalyst, a preparation method thereof and an application thereof. The catalyst has good anti - coking performance, good stability, and the catalyst preparation method is simple and easy to implement.

[0008] In the first aspect of the present invention, a preparation method of a n - hexane isomerization catalyst is provided. The preparation method includes the following contents: (1) Molecular sieve surface treatment: Treat the molecular sieve in an atmosphere of plasma; (2) Active component loading: Mix the precursor solution containing the active component evenly with the material obtained in step (1), and then perform an aging treatment; (3) Crystallization treatment: Mix the material obtained in step (2), water and a template agent evenly for crystallization treatment, and then obtain the n - hexane isomerization catalyst after washing, drying and heat treatment.

[0009] Furthermore, in the above - mentioned preparation method of the n - hexane isomerization catalyst, the molecular sieve in step (1) can be selected from one or more of ZSM - 22 molecular sieve, ZSM - 5 molecular sieve, Y molecular sieve, and preferably ZSM - 22 molecular sieve.

[0010] Furthermore, in the above - mentioned preparation method of the n - hexane isomerization catalyst, the plasma in step (1) is one or more of dielectric barrier discharge plasma, sliding arc discharge plasma, glow discharge plasma, and preferably dielectric barrier discharge plasma.

[0011] Furthermore, in the above - mentioned preparation method of the n - hexane isomerization catalyst, the atmosphere of the plasma in step (1) is derived from an inert gas or a mixture of an inert gas and oxygen. The volume percentage of oxygen in the mixture is 20% - 70%, preferably 30% - 50%; the inert gas is at least one of argon, helium, and nitrogen, and preferably argon.

[0012] Furthermore, in the above - mentioned preparation method of the n - hexane isomerization catalyst, the specific operation process of treating in the atmosphere of plasma in step (1) is as follows: Place the molecular sieve in a plasma reactor, and treat it in an inert gas or a mixture of an inert gas and oxygen at a temperature of 250°C - 500°C, preferably 250°C - 450°C for 0.5 h - 5 h, preferably 0.5 h - 3 h; the volume flow rate of the inert gas or the mixture of an inert gas and oxygen is 20 mL / min - 150 mL / min, preferably 35 mL / min - 100 mL / min.

[0013] Further, in the preparation method of the above-mentioned isomerization catalyst, the treatment of the molecular sieve in step (1) under the plasma atmosphere includes two stages. After the molecular sieve is subjected to the first-stage treatment under the plasma atmosphere, the obtained material is then subjected to the second-stage treatment under the plasma atmosphere; the temperature of the first-stage treatment is 250°C - 350°C, preferably 250°C - 300°C, the treatment time is 0.5 h - 3 h, preferably 0.5 h - 1 h; preferably, the atmosphere of the first-stage treatment is argon; the temperature of the second-stage treatment is 25°C - 250°C higher than that of the first-stage treatment, preferably 50°C - 200°C higher; the treatment time of the second-stage treatment is 0.5 h - 3 h longer than that of the first-stage treatment, preferably 1 h - 2 h longer; preferably, the atmosphere of the second-stage treatment is a mixture of an inert gas and oxygen.

[0014] Further, in the preparation method of the above-mentioned isomerization catalyst, the active components in step (2) are Pt and / or Pd, preferably Pt; the precursor solution containing the active components is one or more of aqueous solutions of chloroplatinic acid, platinum nitrate, dichlorotetraammineplatinum, palladium acetate, palladium chloride, palladium nitrate, sodium chloropalladate, potassium chloropalladate, and dichlorotetraamminepalladium, preferably an aqueous solution of platinum nitrate or dichlorotetraammineplatinum.

[0015] Further, in the preparation method of the above-mentioned isomerization catalyst, the mass ratio of the material obtained in step (1) to the precursor of the active component in step (2) is (20 - 150):1, preferably (30 - 100):1.

[0016] Further, in the preparation method of the above-mentioned isomerization catalyst, the mixing in step (2) can be carried out by an impregnation method, and the impregnation process can be one-step impregnation or multi-step impregnation, preferably multi-step impregnation.

[0017] Further, in the preparation method of the above-mentioned isomerization catalyst, the aging time in step (2) is 2 h - 24 h, preferably 6 h - 10 h, and the aging temperature is 30°C - 100°C, preferably 40°C - 80°C.

[0018] Further, in the preparation method of the above-mentioned isomerization catalyst, an auxiliary agent can also be introduced in step (3). The specific introduction process can be to mix the auxiliary agent with the material obtained in step (2), water, and the template agent evenly and then carry out crystallization treatment; the auxiliary agent is one or more of urea, ammonium oxalate, ammonium carbonate, and ammonium bicarbonate, preferably urea and / or ammonium bicarbonate; the molar ratio of the material obtained in step (2) to the auxiliary agent is 1:(0.1 - 6), preferably 1:(0.5 - 3).

[0019] Further, in the preparation method of the above-mentioned n-alkylation catalyst, the template agent in step (3) is one or more of tetrapropylammonium hydroxide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetraethylammonium hydroxide, and triethylamine, preferably tetrapropylammonium hydroxide.

[0020] Further, in the preparation method of the above-mentioned n-alkylation catalyst, the molar ratio of the material obtained in step (2) in step (3), water, and the template agent is 1:(20 - 100):(0.05 - 4), preferably 1:(30 - 60):(0.1 - 2).

[0021] Further, in the preparation method of the above-mentioned n-alkylation catalyst, the crystallization treatment conditions in step (3) are as follows: the crystallization time is 12 h - 48 h, preferably 12 h - 36 h; the crystallization temperature is 130°C - 250°C, preferably 150°C - 200°C.

[0022] Further, in the preparation method of the above-mentioned n-alkylation catalyst, the drying temperature in step (3) is 80°C - 200°C, preferably 80°C - 120°C; the drying time is 6 h - 48 h, preferably 6 h - 36 h, more preferably 6 h - 24 h.

[0023] Further, in the preparation method of the above-mentioned n-alkylation catalyst, the heat treatment in step (3) can be calcination treatment and / or plasma treatment, preferably plasma treatment.

[0024] Further, when the heat treatment in step (3) of the above-mentioned n-alkylation catalyst preparation method adopts calcination treatment, the calcination treatment temperature is 400°C - 600°C, preferably 450°C - 550°C; the treatment time is 2 h - 6 h, preferably 2 h - 5 h, more preferably 3 h - 4 h.

[0025] Further, when the heat treatment in step (3) of the above-mentioned n-alkylation catalyst preparation method adopts plasma treatment, the specific operation process of the plasma treatment is as follows: the material obtained by drying in step (3) is placed in a plasma reactor, and in an inert atmosphere with a flow rate of 25 mL / min - 60 mL / min, preferably 35 mL / min - 50 mL / min, it is treated at 350°C - 400°C for 1 h - 3 h, preferably 1 h - 2 h.

[0026] Further, in the preparation method of the above-mentioned n-alkylation catalyst, the plasma adopted by the plasma reactor is at least one of dielectric barrier discharge plasma, sliding arc discharge plasma, and glow discharge plasma, preferably dielectric barrier discharge plasma.

[0027] Further, in the preparation method of the above-mentioned isomerization catalyst, the inert atmosphere is one or more of argon, nitrogen or helium, and argon is preferred.

[0028] In the second aspect of the present invention, there is provided an isomerization catalyst obtained by the above preparation method. The catalyst includes a carrier and an active component. The carrier includes molecular sieves, and the molecular sieves are one or more of ZSM-22 molecular sieves, ZSM-5 molecular sieves, and Y molecular sieves, preferably ZSM-22 molecular sieves; the active component is at least one of Group VIII noble metals Pt and Pd, preferably Pt.

[0029] In the third aspect of the present invention, there is provided an application of the above-mentioned isomerization catalyst in the isobutane isomerization reaction process.

[0030] Further, in the above application, the reaction conditions of the isobutane isomerization reaction process are: the reaction temperature is 200°C - 500°C, the reaction pressure is 0.1 MPa - 5.0 MPa, and the feed space velocity is 0.1 h -1 - 10 h -1 .

[0031] Further, in the above application, the catalyst needs to be activated before the reaction, and the activation conditions are: the activation temperature is 200°C - 500°C, and the activation pressure is 0.1 MPa - 5.0 MPa.

[0032] Compared with the prior art, the isomerization catalyst and its preparation method provided by the present invention have the following effects: 1. In the preparation method of the isomerization catalyst provided by the present invention, the Pt / Pd @ molecular sieve catalyst with a core-shell structure is prepared by an in-situ synthesis method, and during the in-situ synthesis process, additives such as urea are added to act synergistically with the plasma. The added additives are subjected to high-temperature treatment in the plasma atmosphere, and they can decompose to generate more defect sites. On the one hand, the defect sites can improve the activity of the catalyst, and under the same reaction conditions, a lower reaction temperature is required; on the other hand, the defect sites can increase the carbon tolerance of the catalyst, so that the obtained catalyst has good anti-coking performance; in addition, the ammonia gas generated by the decomposition of the additives can generate hydrogen under the action of the plasma, thereby realizing the directional reduction of Pt / Pd metals. On the one hand, it can achieve the purpose of saving hydrogen, and on the other hand, it can improve the activity of the catalyst.

[0033] 2. In the preparation method of the isomerization catalyst provided by the present invention, the molecular sieve is subjected to two-stage treatment in the plasma atmosphere, which can further improve the performance of the isomerization catalyst. Embodiment

[0034] To better illustrate the present invention, the following examples and comparative examples are used to further illustrate the present invention. However, the scope of the present invention is not limited to the scope of these examples.

[0035] In the context of this specification, the specific surface area, pore volume, and average pore diameter are measured by the ASAP 2405 physical adsorption instrument of Micromeritics, USA, using the low-temperature liquid nitrogen physical adsorption method. Before measurement, the sample is first heat-treated at 300 °C for 3 h, and then nitrogen is adsorbed at 77 K for testing. The specific surface area of the molecular sieve is calculated by the BET method, and the total pore volume is measured at p / p 0 = 0.98.

[0036] In the present invention, the carbon deposition amount of the catalytic material after the reaction is measured by thermogravimetric analysis. The instrument used is the Mettler Toledo thermal analysis system TGA / DSC 3+. The catalytic materials are all subjected to thermogravimetric testing after reacting at 370 o °C and 3.0 MPa for 24 h. During the testing process, the catalytic material is heated from room temperature to 900 °C in an air atmosphere at a heating rate of 20 °C / min.

[0037] In the present invention, the plasma reactor used in the examples is a dielectric barrier discharge reactor (11 mm o.d. × 8 mm i.d.). A high-voltage electrode with a diameter of 2 mm is inserted in the middle of the reactor, and an aluminum foil sheet with a height of 3 cm is wound around the outer wall as the grounding electrode. The high-voltage electrode and the grounding electrode are respectively connected to the high-voltage electrode and the grounding electrode of the plasma power supply. The model of the plasma power supply used is the CTP-2000K low-temperature plasma power supply. The reactor uses an insulating medium quartz tube to generate a stable plasma.

[0038] In the present invention, the plasma temperature in the examples is controlled by adjusting the power of the plasma power supply. The power of the plasma within the temperature range is between 15 - 36 W.

[0039] Example 1 (1) Surface treatment of molecular sieve Weigh 50 g of ZSM-22 molecular sieve and place it in a dielectric barrier discharge plasma reactor. First, treat it in an argon atmosphere at 250 °C for 1 h at a flow rate of 35 mL / min, and then treat it in an argon and oxygen atmosphere (where the volume percentage of oxygen is 30%) at 350 °C for 3 h at a flow rate of 80 mL / min.

[0040] (2) Loading of noble metal Pt Weigh 1.673 g of platinum nitrate, dissolve it in 10 mL of distilled water, add it to the material obtained in step (1), and age it at 40 °C for 8 h; (3) Crystallization treatment Water, tetrapropylammonium hydroxide, and urea were respectively added to the material obtained in step (2). The molar ratio of the material obtained in step (2), water, tetrapropylammonium hydroxide, and urea was 1:60:1:3. After stirring evenly, it was transferred to a reaction kettle equipped with a polytetrafluoroethylene liner and crystallized at 170 °C for 24 h. After natural cooling, the product was washed with water and then dried in an oven at 120 °C for 12 h; (4) Heat treatment The material obtained in step (3) was placed in a dielectric barrier discharge plasma reaction tube. In an argon atmosphere at 40 mL / min, it was treated at 400 o °C for 2 h to obtain the required isomerization catalyst.

[0041] The above isomerization catalyst was applied to the isobutane isomerization reaction. The reaction conditions were as follows: the reaction temperature was 370 o °C, the reaction pressure was 3.0 MPa, and the space velocity of the raw material gas was 0.77 h -1 . In particular, before the reaction, the catalyst needed to be activated. The activation conditions were: the hydrogen flow rate was 30 mL / min, the activation temperature was 370 °C, and the activation pressure was 3.0 MPa.

[0042] The properties and evaluation results of the catalyst are shown in Table 1.

[0043] Example 2 (1) Molecular sieve surface treatment 50 g of ZSM-22 molecular sieve was weighed and placed in a dielectric barrier discharge plasma reactor. First, it was treated at 250 °C for 1 h in an argon atmosphere at 35 mL / min, and then treated at 300 °C for 3 h in an argon and oxygen atmosphere (where the volume percentage of oxygen was 30%) at 80 mL / min.

[0044] (2) Loading of noble metal Pt 0.862 g of tetraammineplatinum dichloride was weighed and dissolved in 10 mL of distilled water, and then added to the material obtained in step (1). It was aged at 60 °C for 10 h; (3) Crystallization treatment Water, tetrapropylammonium hydroxide, and ammonium bicarbonate were respectively added to the material obtained in step (2). The molar ratio of the material obtained in step (2), water, tetrapropylammonium hydroxide, and ammonium bicarbonate was 1:45:1.5:2. After stirring evenly, it was transferred to a reaction kettle equipped with a polytetrafluoroethylene liner and crystallized at 170 °C for 24 h. After natural cooling, the product was washed with water and then dried in an oven at 120 °C for 12 h; (4) Heat treatment Place the material obtained in step (3) into a dielectric barrier discharge plasma reaction tube. In an argon atmosphere at 40 mL / min, treat it at 375 o °C for 2 h to obtain the required catalyst.

[0045] Apply the above catalyst to the isobutane isomerization reaction. The reaction conditions are as follows: the reaction temperature is 370 o °C, the reaction pressure is 3.0 MPa, and the space velocity of the raw material gas is 0.77 h -1 . In particular, before the reaction, the catalyst needs to be activated. The activation conditions are: the hydrogen flow rate is 30 mL / min, the activation temperature is 370 °C, and the activation pressure is 3.0 MPa.

[0046] The properties and evaluation results of the catalyst are shown in Table 1.

[0047] Example 3 (1) Molecular sieve surface treatment Weigh 50 g of ZSM-22 molecular sieve and place it in a dielectric barrier discharge plasma reactor. First, treat it in an argon atmosphere at 40 mL / min at 250 °C for 1 h, and then treat it in an argon and oxygen atmosphere (where the volume percentage of oxygen is 35%) at 80 mL / min at 350 °C for 3 h.

[0048] (2) Loading of noble metal Pt Weigh 0.573 g of chloroplatinic acid, dissolve it in 10 mL of distilled water, add it to the material obtained in step (1), and age it at 80 °C for 6 h; (3) Crystallization treatment Add water, tetrabutylammonium bromide, and urea to the material obtained in step (2). The molar ratio of the material obtained in step (2), water, tetrabutylammonium bromide, and urea is 1:40:1:0.5. After stirring evenly, transfer it to a reaction kettle equipped with a polytetrafluoroethylene inner lining, crystallize it at 180 °C for 48 h, and after natural cooling, wash the product with water, and then dry it in an oven at 100 °C for 12 h; (4) Heat treatment Place the material obtained in step (3) into a dielectric barrier discharge plasma reaction tube. In a helium atmosphere at 50 mL / min, treat it at 400 o °C for 2 h to obtain the required catalyst.

[0049] Apply the above catalyst to the isobutane isomerization reaction. The reaction conditions are as follows: the reaction temperature is 370 o °C, the reaction pressure is 3.0 MPa, and the space velocity of the raw material gas is 0.77 h -1Specifically, the catalyst needs to be activated before the reaction. The activation conditions are as follows: the hydrogen flow rate is 30 mL / min, the activation temperature is 370 °C, and the activation pressure is 3.0 MPa.

[0050] The properties and evaluation results of the catalyst are shown in Table 1.

[0051] Example 4 (1) Surface treatment of molecular sieve Weigh 50 g of ZSM-22 molecular sieve and place it in a dielectric barrier discharge plasma reactor. First, treat it in an argon atmosphere with a flow rate of 35 mL / min at 250 °C for 1 h, and then treat it in an argon and oxygen atmosphere with a flow rate of 80 mL / min (where the volume percentage of oxygen is 30%) at 350 °C for 3 h.

[0052] (2) Loading of noble metal Pt Weigh 0.826 g of platinum nitrate, dissolve it in 10 mL of distilled water, add it to the material obtained in step (1), and age it at 50 °C for 8 h; (3) Crystallization treatment Add water and tetrapropylammonium hydroxide to the material obtained in step (2). The molar ratio of the material obtained in step (2), water, and tetrapropylammonium hydroxide is 1:50:1. After stirring evenly, transfer it to a reaction kettle equipped with a polytetrafluoroethylene inner liner, crystallize it at 200 °C for 24 h, cool it naturally, wash the product with water, and then dry it in an oven at 120 °C for 12 h; (4) Heat treatment Place the material obtained in step (3) in a dielectric barrier discharge plasma reaction tube, and treat it in an argon atmosphere with a flow rate of 40 mL / min at 400 o °C for 2 h to obtain the required catalyst.

[0053] Apply the above catalyst to the isobutane n-isomerization reaction. The reaction conditions are as follows: the reaction temperature is 370 o °C, the reaction pressure is 3.0 MPa, and the space velocity of the raw material gas is 0.77 h -1 Specifically, the catalyst needs to be activated before the reaction. The activation conditions are as follows: the hydrogen flow rate is 30 mL / min, the activation temperature is 370 °C, and the activation pressure is 3.0 MPa.

[0054] The properties and evaluation results of the catalyst are shown in Table 1.

[0055] Example 5 (1) Surface treatment of molecular sieve Weigh 50 g of ZSM-5 molecular sieve and place it in a dielectric barrier discharge plasma reactor. First, treat it in an argon atmosphere at 300 °C for 1.5 h at a flow rate of 50 mL / min, and then treat it in an argon and oxygen atmosphere (where the volume percentage of oxygen is 50%) at 350 °C for 3 h.

[0056] (2)Loading of noble metal Pt Weigh 0.428 g of tetraammineplatinum dichloride, dissolve it in 10 mL of distilled water, add it to the material obtained in step (1), and age it at 40 °C for 8 h. (3)Crystallization treatment Add water and tetrabutylammonium bromide to the material obtained in step (2). The molar ratio of the material obtained in step (2), water, and tetrabutylammonium bromide is 1:30:0.5. After stirring evenly, transfer it to a reaction kettle equipped with a polytetrafluoroethylene lining, crystallize it at 180 °C for 24 h. After natural cooling, wash the product with water, and then dry it in an oven at 120 °C for 12 h. (4)Heat treatment Calcine the material obtained in step (3) in a muffle furnace at 540 °C for 4 h.

[0057] Apply the above catalyst to the isomerization reaction of isobutane. The reaction conditions are as follows: the reaction temperature is 370 o °C, the reaction pressure is 3.0 MPa, and the space velocity of the raw material gas is 0.77 h -1 . In particular, the catalyst needs to be activated before the reaction. The activation conditions are: the hydrogen flow rate is 30 mL / min, the activation temperature is 370 °C, and the activation pressure is 3.0 MPa.

[0058] The properties and evaluation results of the catalyst are shown in Table 1.

[0059] Example 6 (1)Loading of noble metal Pt Weigh 2.327 g of chloroplatinic acid, dissolve it in 10 mL of distilled water, add it to 50 g of Y-type molecular sieve, and age it at 40 °C for 8 h. (2)Crystallization treatment Add water and tetrapropylammonium hydroxide to the material obtained in step (1). The molar ratio of the material obtained in step (2), water, and tetrapropylammonium hydroxide is 1:60:2. After stirring evenly, transfer it to a reaction kettle equipped with a polytetrafluoroethylene lining, crystallize it at 200 °C for 24 h. After natural cooling, wash the product with water, and then dry it in an oven at 120 °C for 12 h. (3)Heat treatment Place the material obtained in step (2) into a dielectric barrier discharge plasma reaction tube. In an argon atmosphere at 40 mL / min, treat it at 400 o °C for 2 h to obtain the required catalyst.

[0060] Apply the above catalyst to the isobutane isomerization reaction. The reaction conditions are as follows: the reaction temperature is 370 o °C, the reaction pressure is 3.0 MPa, and the space velocity of the raw material gas is 0.77 h -1 . Specifically, the catalyst needs to be activated before the reaction. The activation conditions are: the hydrogen flow rate is 30 mL / min, the activation temperature is 370 °C, and the activation pressure is 3.0 MPa.

[0061] The properties and evaluation results of the catalyst are shown in Table 1.

[0062] Comparative Example 1 (1) Loading of noble metal Pt Weigh 0.825 g of platinum nitrate, dissolve it in 3 mL of distilled water, add it to 50 g of ZSM-22 molecular sieve, and age it at 40 °C for 8 h; (2) Crystallization treatment Add water and tetrapropylammonium hydroxide to the material obtained in step (1). The molar ratio of the material obtained in step (1), water, and tetrapropylammonium hydroxide is 1:60:1. After stirring evenly, transfer it to a reaction kettle equipped with a polytetrafluoroethylene inner lining, crystallize it at 170 °C for 24 h, cool it naturally, wash the product with water, and then dry it in an oven at 120 °C for 12 h; (3) Heat treatment Calcine the material obtained in step (3) in a muffle furnace at 540 °C for 4 h.

[0063] Apply the above catalyst to the isobutane isomerization reaction. The reaction conditions are as follows: the reaction temperature is 370 o °C, the reaction pressure is 3.0 MPa, and the space velocity of the raw material gas is 0.77 h -1 . Specifically, the catalyst needs to be activated before the reaction. The activation conditions are: the hydrogen flow rate is 30 mL / min, the activation temperature is 370 °C, and the activation pressure is 3.0 MPa.

[0064] The properties and evaluation results of the catalyst are shown in Table 1.

[0065] Table 1 Properties and evaluation results of the catalyst

Claims

1. A preparation method of a skeletal isomerization catalyst, characterized in that: The preparation method includes the following contents: (1) Molecular sieve surface treatment: treating the molecular sieve in a plasma atmosphere; (2) Active component loading: mixing the precursor solution containing the active component evenly with the material obtained in step (1), and then performing an aging treatment; (3) Crystallization treatment: mixing the material obtained in step (2), water and a template agent evenly for crystallization treatment, and then obtaining the skeletal isomerization catalyst after washing, drying and heat treatment.

2. The method according to claim 1, characterized in that: The molecular sieve in step (1) is selected from one or more of ZSM-22 molecular sieve, ZSM-5 molecular sieve, and Y molecular sieve, preferably ZSM-22 molecular sieve.

3. The method according to claim 1, characterized in that: The plasma in step (1) is one or more of dielectric barrier discharge plasma, sliding arc discharge plasma, and glow discharge plasma, preferably dielectric barrier discharge plasma.

4. The method according to claim 1, characterized in that: The atmosphere of the plasma in step (1) is derived from an inert gas or a mixture of an inert gas and oxygen. The volume percentage content of oxygen in the mixture is 20%-70%, preferably 30%-50%; the inert gas is at least one of argon, helium, and nitrogen, preferably argon.

5. The method according to claim 1, characterized in that: The specific operation process of treating in the plasma atmosphere in step (1) is as follows: placing the molecular sieve in a plasma reactor, in an inert gas or a mixture of an inert gas and oxygen, at a temperature of 250°C - 500°C, preferably 250°C - 450°C, for 0.5 h - 5 h, preferably 0.5 h - 3 h; the volume flow rate of the inert gas or the mixture of an inert gas and oxygen is 20 mL / min - 150 mL / min, preferably 35 mL / min - 100 mL / min.

6. The method according to claim 1, characterized in that: The treatment of the molecular sieve in the plasma atmosphere in step (1) includes two stages. After the molecular sieve is subjected to a first-stage treatment in the plasma atmosphere, the obtained material is then subjected to a second-stage treatment in the plasma atmosphere; the first-stage treatment temperature is 250°C - 350°C, preferably 250°C - 300°C, and the treatment time is 0.5 h - 3 h, preferably 0.5 h - 1 h; preferably, the atmosphere of the first-stage treatment is argon; the second-stage treatment temperature is 25°C - 250°C higher than the first-stage treatment temperature, preferably 50°C - 200°C higher; the second-stage treatment time is 0.5 h - 3 h longer than the first-stage treatment time, preferably 1 h - 2 h longer; preferably, the atmosphere of the second-stage treatment is a mixture of an inert gas and oxygen.

7. The method according to claim 1, characterized in that: The active component in step (2) is Pt and / or Pd, preferably Pt; the precursor solution containing the active component is one or more of the aqueous solutions of chloroplatinic acid, platinum nitrate, dichlorotetraammineplatinum, palladium acetate, palladium chloride, palladium nitrate, sodium chloropalladate, potassium chloropalladate, and dichlorotetraamminepalladium, preferably the aqueous solution of platinum nitrate or dichlorotetraammineplatinum.

8. According to the method described in claim 1, it is characterized in that: In step (2), the mass ratio of the material obtained in step (1) to the precursor of the active component is (20 - 150):1, preferably (30 - 100):

1.

9. According to the method described in claim 1, it is characterized in that: The mixing in step (2) is carried out by the impregnation method, and the impregnation process is one-step impregnation or multi-step impregnation, preferably multi-step impregnation.

10. According to the method described in claim 1, it is characterized in that: The aging time in step (2) is 2 h - 24 h, preferably 6 h - 10 h, and the aging temperature is 30°C - 100°C, preferably 40°C - 80°C.

11. According to the method described in claim 1, it is characterized in that: In step (3), a promoter can also be introduced. The specific introduction process is to mix the promoter with the material obtained in step (2), water, and the template agent evenly and then carry out crystallization treatment; the promoter is one or more of urea, ammonium oxalate, ammonium carbonate, and ammonium bicarbonate, preferably urea and / or ammonium bicarbonate; the molar ratio of the material obtained in step (2) to the promoter is 1:(0.1~6), preferably 1:(0.5~3).

12. According to the method described in claim 1, it is characterized in that: The template agent in step (3) is one or more of tetrapropylammonium hydroxide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetraethylammonium hydroxide, and triethylamine, preferably tetrapropylammonium hydroxide.

13. According to the method described in claim 1, it is characterized in that: In step (3), the molar ratio of the material obtained in step (2), water, and the template agent is 1:(20~100):(0.05~4), preferably 1:(30~60):(0.1~2).

14. According to the method described in claim 1, it is characterized in that: The crystallization treatment conditions in step (3) are as follows: the crystallization time is 12 h - 48 h, preferably 12 h - 36 h; the crystallization temperature is 130°C - 250°C, preferably 150°C - 200°C.

15. According to the method described in claim 1, it is characterized in that: The drying temperature in step (3) is 80°C - 200°C, preferably 80°C - 120°C; the drying time is 6 h - 48 h, preferably 6 h - 36 h, more preferably 6 h - 24 h.

16. According to the method described in claim 1, it is characterized in that: The heat treatment in step (3) is calcination treatment and / or plasma treatment, preferably plasma treatment.

17. According to the method described in claim 16, it is characterized in that: When the heat treatment in step (3) is carried out by roasting treatment, the roasting treatment temperature is 400°C - 600°C, preferably 450°C - 550°C; the treatment time is 2h - 6h, preferably 2h - 5h, and more preferably 3h - 4h.

18. According to the method described in claim 16, it is characterized in that: When the heat treatment in step (3) is carried out by plasma treatment, the specific operation process of the plasma treatment is as follows: Place the material obtained by drying in step (3) in a plasma reactor, and in an inert atmosphere with a flow rate of 25 mL / min - 60 mL / min, preferably 35 mL / min - 50 mL / min, treat it at 350°C - 400°C for 1 h - 3 h, preferably 1 h - 2 h.

19. A n - hexane isomerization catalyst obtained by using the preparation method described in any one of claims 1 - 18.

20. Application of the n - hexane isomerization catalyst described in claim 19 in the isomerization reaction process of isobutane.

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