Catalytic gasoline olefin-reducing aromatization catalyst, preparation method and application thereof

Abstract

The present application relates to the technical field of olefin aromatization catalyst, and is a catalytic gasoline olefin aromatization catalyst, a preparation method and application thereof, wherein the former comprises a carrier, ZSM-5 molecular sieve and active metal oxide; an aluminum source, a silicon source and an alkali source are mixed, ZSM-5 molecular sieve is added to obtain a first gel mixture, the first gel mixture is subjected to a first-stage hydrothermal crystallization reaction and a second-stage hydrothermal crystallization reaction, and then is cooled, washed, dried, calcined, added to an ammonium solution, exchanged, suction filtered, washed, dried, calcined, mixed with alumina to form a shape, dried, calcined to obtain a calcined product, impregnated with an active component impregnation solution, and then dried and calcined to obtain the product. The present application has the advantages of simple synthesis process, low cost and environmental protection, and can be used in catalytic gasoline aromatization reaction, has the functions of sulfur resistance and aromatization, has high olefin aromatization degree, and the product can be used as a reforming raw material to realize the purpose of increasing chemical product aromatic hydrocarbons.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of olefin aromatization catalyst, and is a catalytic gasoline olefin aromatization catalyst, a preparation method and application thereof. BACKGROUND

[0002] With the increasing emphasis on environmental protection, China has accelerated the pace of upgrading the quality of vehicle fuels, and the national standard GB17930-2016 requires that the sulfur content in Guo VI b gasoline is not more than 10 µg / g, and the olefin volume content is not more than 15% [M1].

[0003] Catalytic cracking gasoline is the main component of vehicle gasoline in China, accounting for about 75% in the gasoline pool, and it is characterized by high olefin and sulfur content. The method commonly used for desulfurization and olefin reduction is to first fractionate the catalytic gasoline into light and heavy gasoline, etherize the light gasoline to obtain etherified gasoline, and selectively hydrogenate the heavy gasoline or adsorb the sulfur. Desulfurization is then achieved, and olefin aromatization and isomerization processes are used to restore the octane value. Gasoline aromatization can convert a large amount of olefins in FCC gasoline into aromatic hydrocarbons, and the aromatization product can be used as a high-octane gasoline blending component or as a reforming raw material. At the present stage, desulfurization and aromatization of catalytic gasoline are usually carried out separately, which can reduce the damage of sulfur to the aromatization catalyst, but also makes the process longer and more olefins are saturated. Therefore, developing a catalyst with both sulfur tolerance and olefin aromatization has become the research direction today.

[0004] In the olefin aromatization catalyst, ZSM-5 molecular sieve is widely used. ZSM-5 molecular sieve is a kind of solid acid catalyst with excellent performance, and its unique pore structure provides excellent shape selection function for desulfurization and olefin aromatization reaction. However, due to the small size of the ten-membered ring pore of ZSM-5 molecular sieve, the diffusion and mass transfer of reaction intermediates and products in the pore are limited, especially when the carbon deposition is high, which leads to low olefin conversion rate, poor sulfur tolerance and stability. In addition, organic template is usually introduced in the synthesis process of ZSM-5 molecular sieve to guide the synthesis. The organic template is expensive and needs to be used in large quantities, which greatly increases the cost of the catalyst. Moreover, amine recovery and waste liquid treatment are required, which is complicated and pollutes the environment. Therefore, the addition of organic template should be avoided in the synthesis, and seed crystal guided synthesis can be used to replace the organic template, so as to reduce the cost and environmental pollution of the molecular sieve, and improve the pore structure and acidity of the molecular sieve by crystallization, post-treatment modification, etc. to obtain a molecular sieve with gradient pore structure and improve the desulfurization and aromatization performance of gasoline.

[0005] Chinese invention patent CN104030314A discloses a method for preparing ZSM-5 molecular sieves with a hierarchical porous structure. This method utilizes tetrapropylammonium bromide as a template agent and employs inexpensive raw materials to prepare the material in one step. The method is low-cost, simple to operate, and yields hierarchical porous materials with excellent physicochemical properties and catalytic characteristics.

[0006] Chinese invention patent with publication number CN104649295A discloses the preparation and application of a hierarchical porous ZSM-5 molecular sieve aggregate. Its feature is that a seed crystal prepared by adding tetrapropylammonium as a directing agent is added to a silica-alumina sol gel synthesized from inorganic aluminum source and inorganic silicon source to synthesize a hierarchical porous ZSM-5 molecular sieve with open channels in one step.

[0007] Kong Feifei et al. from Liaoning University of Petroleum and Chemical Technology studied the hydrodesulfurization and olefin aromatization reactions of ZSM-5 catalyst. They treated ZSM-5 molecular sieves with different silica-to-alumina ratios using Na2CO3 solution and a mixed alkaline solution of Na2CO3 and TPAOH. The mixed alkaline treatment increased the specific surface area and mesopore volume of the molecular sieves. Using FCC gasoline as feedstock, the hydrodesulfurization and olefin aromatization performance of the alkaline-treated Co-Mo / ZSM-5 catalyst was evaluated. The results showed that at 400℃, 2.5 MPa, a hydrogen-to-oil volume ratio of 300:1, and a reaction space velocity of 1.5 h⁻¹, the reaction was optimal. -1 Under these conditions, the desulfurization rate was 94.2% and the aromatics yield was 30.82%.

[0008] Wang Jincheng et al. studied the aromatization of light gasoline catalytic cracking on nano-HZSM-5 zeolite catalyst. They synthesized nano-HZSM-5 zeolite molecular sieve using an organic template agent and then aromatized FCC light gasoline. The reaction was carried out at temperatures ranging from 360℃ to 400℃, reaction pressures from 1.0 MPa to 3.0 MPa, and a WHSV of 1.0 h⁻¹. -1 Up to 4.0h -1 Under these conditions, C5 + The conversion rate of olefins ranged from 39.11% to 97.92%, and the net increase in aromatics in the products ranged from 2.59% to 19.05%. Low gasoline yield and rapid catalyst deactivation were the main problems in the aromatization reaction of FCC light gasoline on nano HZSM-5 zeolite catalyst.

[0009] Chinese invention patent CN104399518B discloses a method for preparing an aromatization catalyst for catalytic cracking of light gasoline. The method mainly includes modification with nano-ZSM-5 molecular sieves, preparation of the support, and catalyst preparation. The nano-ZSM-5 molecular sieves have short pores and high mass transfer efficiency. After surface modification with one or two metals from rare earth elements or cobalt, molybdenum, nickel, gallium, and zinc, it can minimize the reduction of low-carbon olefins in catalytic cracking of light gasoline while maintaining or even increasing the octane number.

[0010] Chinese invention patent CN1235682C discloses a catalytic gasoline aromatization catalyst and its application process. Based on the weight percentage of the catalyst, its composition is as follows: precious metal content from 0.1 m% to 1.0 m%; K-type zeolite content from 50.0 m% to 90.0 m%; K₂O content from 1.0 m% to 5.0 m%; and the balance being a binder. This catalyst can aromatize hydrodesulfurized catalytic gasoline, achieving the goal of reducing olefin content and minimizing octane number loss. However, the presence of precious metals such as platinum and palladium increases the catalyst cost and makes it susceptible to sulfur poisoning.

[0011] Chinese invention patent with authorization announcement number CN108659883BX discloses a method and system for gasoline desulfurization and aromatization. The method includes: (1) cutting gasoline feedstock to obtain a first light gasoline fraction and a first heavy gasoline fraction; (2) feeding the first heavy gasoline fraction into a first fluidized bed reactor and contacting it with a mixed catalyst to carry out desulfurization and aromatization reaction under hydrogen conditions; feeding the first light gasoline fraction into a second fluidized bed reactor and contacting it with an adsorption desulfurization catalyst to carry out desulfurization reaction; (3) cutting the desulfurization and aromatization products of the first heavy gasoline fraction to obtain a second light gasoline fraction and a second heavy gasoline fraction; (4) etherifying the light gasoline obtained from the two desulfurization processes to obtain etherified oil, and blending it with the second heavy gasoline fraction in a gasoline pool, thereby reducing sulfur and olefins in gasoline while maintaining octane number and high gasoline yield. The mixed catalyst in step (2) is the core of the reaction system. It is a mixture of adsorption desulfurization catalyst and olefin aromatization catalyst. The adsorption desulfurization catalyst contains 5% to 85% silica, 5% to 30% alumina, 10% to 90% zinc oxide and 5% to 30% desulfurization active metal; the olefin aromatization catalyst contains 10% to 30% molecular sieve, 0.1% to 20% aromatization active metal oxide and 50% to 89% support.

[0012] Although this method can reduce the sulfur and olefin content in gasoline, it requires two fluidized reactors and two cutting processes, resulting in a long reaction process. Furthermore, the catalysts are of two different types, making it difficult to match their desulfurization and olefin aromatization performance. The active component of the aromatization catalyst is a microporous molecular sieve, and the synthesis of the molecular sieve requires multiple acid and alkali treatment processes, making the process complex, costly, and environmentally unfriendly. The catalyst also results in a low degree of olefin aromatization, with the product containing only 17% to 19% olefins and 18% to 20% aromatics, making it suitable only as a gasoline blending component. Summary of the Invention

[0013] This invention provides a catalyst for the olefin aromatization of gasoline, its preparation method, and its application, overcoming the shortcomings of the prior art. It can effectively solve the problems of complex process, high cost, environmental unfriendliness, and low degree of olefin aromatization in the preparation of existing olefin aromatization catalysts.

[0014] One of the technical solutions of the present invention is achieved through the following measures: a catalytic gasoline olefin aromatization catalyst, comprising 30% to 85% support, 10% to 50% ZSM-5 molecular sieve and 0.1% to 20% active metal oxide by weight percentage, wherein the support is alumina, the ZSM-5 molecular sieve is an industrially modified ZSM-5 molecular sieve or a self-made molecular sieve, and the active metal oxide is one or more of nickel oxide, molybdenum oxide, cobalt oxide, zinc oxide, lanthanum oxide and gallium oxide.

[0015] The following are further optimizations and / or improvements to one of the above-mentioned inventive technical solutions:

[0016] The above-mentioned industrial modified ZSM-5 molecular sieve was prepared by the following method: First, industrial ZSM-5 seed crystals and modification solution were mixed evenly at a solid-liquid ratio of 1:10 to 40, and stirred at 20℃ to 100℃ for 2h to 50h; then, after washing with deionized water, the mixture was dried at 80℃ to 150℃ for 2h to 20h, and calcined at 400℃ to 700℃ for 2h to 10h to obtain industrial modified ZSM-5 molecular sieve, wherein the modification solution was an alkaline solution or acidic solution with a concentration of 0.10mol / L to 5.0mol / L.

[0017] The alkaline solution mentioned above is one or more of sodium hydroxide solution, sodium carbonate solution, and sodium acetate solution, and the acidic solution is one or more of hydrochloric acid solution, nitric acid solution, and sulfuric acid solution.

[0018] The above-mentioned material was prepared according to the following method: First, an aluminum source, a silicon source, and an alkali source were mixed uniformly at a molar ratio of 1 to 10:100 to 1000:10 to 50. Then, ZSM-5 molecular sieve was added, and the mixture was stirred at 10°C to 40°C for 2 to 40 hours to obtain a first gel mixture. The weight of the ZSM-5 molecular sieve accounted for 2% to 15% of the weight of silica in the added silicon source. Second, the first gel mixture was placed in a sealed container and subjected to a first-stage hydrothermal crystallization reaction at 100°C to 150°C for 6 hours. The first hydrothermal crystallization product was obtained after 72 hours. The third step involved subjecting the first hydrothermal crystallization product to a second hydrothermal crystallization reaction at 130°C to 200°C for 12 to 72 hours to obtain the second hydrothermal crystallization product. The fourth step involved cooling the second hydrothermal crystallization product, washing it with deionized water, drying it at 80°C to 150°C for 2 to 20 hours, and then calcining it at 400°C to 700°C for 2 to 10 hours to obtain a sodium-type ZSM-5 molecular sieve with a stepped pore structure. The fifth step involved further processing the sodium-type ZSM-5 molecular sieve with a stepped pore structure... ZSM-5 molecular sieve was added to an ammonium solution at a solid-liquid ratio of 1:5 to 20, and exchanged at 40°C to 90°C for 2 to 6 hours. After the exchange, the mixture was filtered, washed, dried, and calcined to obtain a hydrogen-form ZSM-5 molecular sieve with a stepped pore structure. In the sixth step, the hydrogen-form ZSM-5 molecular sieve with the stepped pore structure was mixed with the required amount of alumina, and dilute acid was added to knead and bind it together. The mixture was then extruded into strips, and the formed product was dried at 80°C to 150°C for 2 to 20 hours, and then further dried at 400°C. The product is calcined at 700℃ for 2 to 10 hours to obtain the calcined product. In the seventh step, the calcined product is crushed and sieved, and an active component impregnation solution is prepared according to the weight percentage of active metal oxides of 0.1% to 20%. The active component impregnation solution is then slowly added dropwise to the sieved catalyst support and impregnated at 0℃ to 40℃ for 2 to 40 hours. Then, it is dried at 80℃ to 150℃ for 2 to 20 hours and calcined at 400℃ to 700℃ for 2 to 10 hours to obtain the catalytic gasoline olefin aromatization catalyst.

[0019] In the first step above, the aluminum source is one or more of sodium aluminate, gamma alumina, boehmite, aluminum isopropoxide, and aluminum hydroxide; the silicon source is one or more of silica sol, silica gel, tetraethyl orthosilicate, and silica; and the alkali source is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium acetate.

[0020] In the fifth step above, the ammonium solution is one or more of the following: ammonium nitrate solution, ammonium chloride solution, and ammonium sulfate solution with a concentration of 0.2 mol / L to 1 mol / L.

[0021] In the sixth step above, the alumina is one or more of gamma alumina, boehmite, and aluminum hydroxide, and the dilute acid is one or more of dilute hydrochloric acid, dilute nitric acid, dilute citric acid, and dilute acetic acid, with a mass percentage of 0.5% to 10%.

[0022] In the seventh step above, the active component in the active component impregnation solution is one or more of the following: nickel nitrate, nickel sulfate, ammonium molybdate, molybdenum trioxide, cobalt chloride, cobalt sulfate, cobalt nitrate, zinc chloride, zinc nitrate, zinc oxide, zinc sulfate, lanthanum nitrate, gallium nitrate, gallium sulfate, and gallium chloride.

[0023] The second technical solution of the present invention is achieved through the following measures: A method for preparing a catalyst for the olefin aromatization of catalytic gasoline, comprising the following steps: First, an aluminum source, a silicon source, and an alkaline source are mixed uniformly in a molar ratio of 1 to 10: 100 to 1000: 10 to 50, and then ZSM-5 molecular sieve is added. The mixture is stirred at 10°C to 40°C for 2 to 40 hours to obtain a first gel mixture, wherein the weight of the ZSM-5 molecular sieve accounts for 2% to 15% of the weight of silica in the added silicon source; Second, the first gel mixture is placed into a sealed container. Then, a first-stage hydrothermal crystallization reaction is carried out at 100℃ to 150℃ for 6 hours to 72 hours to obtain the first-stage hydrothermal crystallization product. In the third step, the first-stage hydrothermal crystallization product is subjected to a second-stage hydrothermal crystallization reaction at 130℃ to 200℃ for 12 hours to 72 hours to obtain the second-stage hydrothermal crystallization product. In the fourth step, the second-stage hydrothermal crystallization product is cooled, washed with deionized water, dried at 80℃ to 150℃ for 2 hours to 20 hours, and then calcined at 400℃ to 700℃ for 2 hours to 10 hours to obtain a sodium-type ZSM- with a stepwise porous structure. 5. Molecular sieve; Fifth step: Sodium-type ZSM-5 molecular sieve with a stepped pore structure is added to an ammonium solution at a solid-liquid ratio of 1:5 to 20, and exchanged at 40℃ to 90℃ for 2 to 6 hours. After the exchange, it is filtered, washed, dried, and calcined to obtain hydrogen-type ZSM-5 molecular sieve with a stepped pore structure; Sixth step: Hydrogen-type ZSM-5 molecular sieve with a stepped pore structure is mixed with the required amount of alumina, and dilute acid is added to knead it to make it bind, then extruded into strips. The formed product is dried at 80℃ to 150℃ for 2 hours. The product is calcined for 20 hours and then calcined at 400℃ to 700℃ for 2 to 10 hours to obtain the calcined product. In the seventh step, the calcined product is crushed and sieved, and an active component impregnation solution is prepared according to the weight percentage of active metal oxides of 0.1% to 20%. The active component impregnation solution is then slowly added dropwise to the sieved catalyst support and impregnated at 0℃ to 40℃ for 2 to 40 hours. Then, it is dried at 80℃ to 150℃ for 2 to 20 hours and calcined at 400℃ to 700℃ for 2 to 10 hours to obtain the catalytic gasoline olefin aromatization catalyst.

[0024] The third technical solution of the present invention is achieved through the following measures: the application of a catalyst for catalytic gasoline de-olefin aromatization in the catalytic gasoline de-olefin aromatization reaction.

[0025] The preparation process of the stepped-pore molecular sieve of this invention is simple, with low production cost and minimal environmental pollution. The prepared catalytic gasoline olefin aromatization catalyst has dual functions of sulfur resistance and aromatization. It can be carried out in one reactor without cutting, shortening the reaction process. It is used in the catalytic gasoline aromatization to achieve a high degree of olefin aromatization, with an olefin content of <16% and an aromatic content of >40% in the product. The aromatized product can be used as a reforming feedstock, thereby achieving the goal of increasing the aromatic content of chemical products. Detailed Implementation

[0026] This invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solutions and actual conditions of this invention. Unless otherwise specified, all chemical reagents and chemicals mentioned in this invention are well-known and commonly used chemical reagents and chemicals in the prior art; unless otherwise specified, all percentages in this invention are mass percentages; unless otherwise specified, all solutions in this invention are aqueous solutions with water as the solvent, for example, hydrochloric acid solution is an aqueous solution of hydrochloric acid; room temperature in this invention generally refers to a temperature between 15°C and 25°C, generally defined as 25°C.

[0027] The present invention will be further described below with reference to embodiments:

[0028] Example 1: The catalytic gasoline olefin aromatization catalyst comprises, by weight percentage, 30% to 85% support, 10% to 50% ZSM-5 molecular sieve, and 0.1% to 20% active metal oxide, wherein the support is alumina, the ZSM-5 molecular sieve is industrially modified ZSM-5 molecular sieve or self-made molecular sieve, and the active metal oxide is one or more of nickel oxide, molybdenum oxide, cobalt oxide, zinc oxide, lanthanum oxide, and gallium oxide.

[0029] In this invention, when the ZSM-5 molecular sieve is a self-made molecular sieve (commercially available), it can be added directly, or it can be modified with a modification solution to obtain an industrially modified ZSM-5 molecular sieve before being added.

[0030] Example 2: As an optimization of the above example, industrial modified ZSM-5 molecular sieve was prepared according to the following method: First, industrial ZSM-5 seed crystals and modification solution were mixed evenly at a solid-liquid ratio of 1:10 to 40, and stirred at 20°C to 100°C for 2 to 50 hours; then, after washing with deionized water, the mixture was dried at 80°C to 150°C for 2 to 20 hours, and calcined at 400°C to 700°C for 2 to 10 hours to obtain industrial modified ZSM-5 molecular sieve, wherein the modification solution was an alkaline solution or an acidic solution with a concentration of 0.10 mol / L to 5.0 mol / L.

[0031] Example 3: As an optimization of the above examples, the alkaline solution is one or more of sodium hydroxide solution, sodium carbonate solution and sodium acetate solution, and the acidic solution is one or more of hydrochloric acid solution, nitric acid solution and sulfuric acid solution.

[0032] Example 4: As an optimization of the above examples, the following method was used to prepare the mixture: First, aluminum source, silicon source, and alkali source were mixed evenly in a molar ratio of 1 to 10: 100 to 1000: 10 to 50, and then ZSM-5 molecular sieve was added. The mixture was stirred at 10°C to 40°C for 2 to 40 hours to obtain a first gel mixture, wherein the weight of ZSM-5 molecular sieve accounted for 2% to 15% of the weight of silica in the added silicon source; Second, the first gel mixture was placed in a sealed container and subjected to a first... The first hydrothermal crystallization reaction is carried out for 6 to 72 hours to obtain the first hydrothermal crystallization product. The second hydrothermal crystallization product is then subjected to a second hydrothermal crystallization reaction at 130°C to 200°C for 12 to 72 hours. The second hydrothermal crystallization product is then cooled, washed with deionized water, dried at 80°C to 150°C for 2 to 20 hours, and then calcined at 400°C to 700°C for 2 to 10 hours to obtain a sodium-type ZSM-5 molecular sieve with a stepped pore structure. The third step involves further processing the product into a series of steps. Sodium-type ZSM-5 molecular sieves with hierarchical pore structure are added to an ammonium solution at a solid-liquid ratio of 1:5 to 20 and exchanged at 40°C to 90°C for 2 to 6 hours. After the exchange, the mixture is filtered, washed, dried, and calcined to obtain hydrogen-type ZSM-5 molecular sieves with a hierarchical pore structure. In the sixth step, the hydrogen-type ZSM-5 molecular sieves with a hierarchical pore structure are mixed with the required amount of alumina, and dilute acid is added to knead and bind the mixture. The mixture is then extruded and formed into strips. The formed product is dried at 80°C to 150°C for 2 to 20 hours and then further dried at 4°C. The product is calcined at 00℃ to 700℃ for 2 to 10 hours to obtain the calcined product. In the seventh step, the calcined product is crushed and sieved, and an active component impregnation solution is prepared according to the weight percentage of active metal oxides of 0.1% to 20%. The active component impregnation solution is then slowly added dropwise to the sieved catalyst support and impregnated at 0℃ to 40℃ for 2 to 40 hours. After that, it is dried at 80℃ to 150℃ for 2 to 20 hours and calcined at 400℃ to 700℃ for 2 to 10 hours to obtain the catalytic gasoline olefin aromatization catalyst.

[0033] In this invention, the sealed container into which the first gel mixture is placed can be a stainless steel high-pressure reactor lined with polytetrafluoroethylene.

[0034] Example 5: As an optimization of the above example, in the first step, the aluminum source is one or more of sodium aluminate, gamma alumina, boehmite, aluminum isopropoxide and aluminum hydroxide, the silicon source is one or more of silica sol, silica gel, tetraethyl orthosilicate and silica, and the alkali source is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate and sodium acetate.

[0035] Example 6: As an optimization of the above example, in the fifth step, the ammonium solution is one or more of ammonium nitrate solution, ammonium chloride solution and ammonium sulfate solution with a concentration of 0.2 mol / L to 1 mol / L.

[0036] Example 7: As an optimization of the above example, in step 6, the alumina is one or more of gamma alumina, boehmite and aluminum hydroxide, and the dilute acid is one or more of dilute hydrochloric acid, dilute nitric acid, dilute citric acid and dilute acetic acid with a mass percentage of 0.5% to 10%.

[0037] Example 8: As an optimization of the above example, in step 7, the active component in the active component impregnation solution is one or more of nickel nitrate, nickel sulfate, ammonium molybdate, molybdenum trioxide, cobalt chloride, cobalt sulfate, cobalt nitrate, zinc chloride, zinc nitrate, zinc oxide, zinc sulfate, lanthanum nitrate, gallium nitrate, gallium sulfate, and gallium chloride.

[0038] Example 9: The preparation method of this catalytic gasoline olefin aromatization catalyst is carried out according to the following steps: First, aluminum source, silicon source, and alkali source are mixed evenly in a molar ratio of 1 to 10: 100 to 1000: 10 to 50, and then ZSM-5 molecular sieve is added. The mixture is stirred at 10°C to 40°C for 2 to 40 hours to obtain a first gel mixture, wherein the weight of ZSM-5 molecular sieve accounts for 2% to 15% of the weight of silica in the added silicon source; Second, the first gel mixture is placed in a sealed container and then incubated at 100°C to 150°C. The first hydrothermal crystallization reaction is carried out for 6 to 72 hours under certain conditions to obtain the first hydrothermal crystallization product. The second hydrothermal crystallization product is then subjected to a second hydrothermal crystallization reaction at 130°C to 200°C for 12 to 72 hours to obtain the second hydrothermal crystallization product. The second hydrothermal crystallization product is cooled, washed with deionized water, dried at 80°C to 150°C for 2 to 20 hours, and then calcined at 400°C to 700°C for 2 to 10 hours to obtain a sodium-type ZSM-5 molecular sieve with a stepwise pore structure. The fifth step... Sodium-type ZSM-5 molecular sieves with a tiered pore structure are added to an ammonium solution at a solid-liquid ratio of 1:5 to 20. The solution is exchanged at 40°C to 90°C for 2 to 6 hours. After the exchange, the mixture is filtered, washed, dried, and calcined to obtain hydrogen-type ZSM-5 molecular sieves with a tiered pore structure. In the sixth step, the hydrogen-type ZSM-5 molecular sieves with a tiered pore structure are mixed with the required amount of alumina, and dilute acid is added to knead and bind the mixture. The mixture is then extruded into strips, and the formed product is dried at 80°C to 150°C for 2 to 20 hours. The product is calcined at 400℃ to 700℃ for 2 to 10 hours to obtain the calcined product. In the seventh step, the calcined product is crushed and sieved, and an active component impregnation solution is prepared according to the weight percentage of active metal oxides of 0.1% to 20%. The active component impregnation solution is then slowly added dropwise to the sieved catalyst support and impregnated at 0℃ to 40℃ for 2 to 40 hours. After that, it is dried at 80℃ to 150℃ for 2 to 20 hours and calcined at 400℃ to 700℃ for 2 to 10 hours to obtain the catalytic gasoline olefin aromatization catalyst.

[0039] Example 10: Application of the catalyst for catalytic gasoline de-olefin aromatization in the catalytic gasoline de-olefin aromatization reaction.

[0040] Example 11: 10g of industrial ZSM-5 molecular sieve (of which the mass percentage of silicon and aluminum is 120) was mixed evenly with 100g of 0.1mol / L NaOH solution, stirred at 60℃ for 4h, washed with deionized water, dried at 80℃ for 10h, and calcined at 500℃ for 2h to obtain industrial modified ZSM-5 molecular sieve.

[0041] The catalytic gasoline olefin aromatization catalyst was prepared according to the following method: First, sodium aluminate, tetraethyl orthosilicate, and sodium acetate were mixed uniformly in a molar ratio of 1:120:10, and then industrially modified ZSM-5 molecular sieve was added, with the weight of the industrially modified ZSM-5 molecular sieve accounting for 10% of the weight of the added silica; the mixture was stirred at 20°C for 6 hours to obtain a first gel mixture; Second, the first gel mixture was placed in a reaction vessel lined with polytetrafluoroethylene and subjected to hydrothermal crystallization at 100°C for 12 hours in an oven to obtain the first stage of hydrothermal crystallization product; Third, hydrothermal crystallization was carried out at 160°C for 48 hours to obtain the second stage of hydrothermal crystallization product; Fourth, after crystallization, the mixture was cooled, washed, dried at 120°C for 12 hours, and then calcined at 520°C for 4 hours to obtain a sodium-type ZSM-5 molecular sieve with a stepped pore structure; Fifth, the sodium-type ZSM-5 molecular sieve with a stepped pore structure was further... The molecular sieve was placed in a 1 mol / L ammonium chloride solution at a weight ratio of 1:10 and exchanged at 80°C for 3 hours. After washing, drying, and calcination, a hydrogen-form ZSM-5 molecular sieve with a stepped pore structure was obtained. In the sixth step, the hydrogen-form ZSM-5 molecular sieve powder with a stepped pore structure was mixed with boehmite at a mass percentage ratio of 60%:40%, and then 3% dilute nitric acid was added dropwise for kneading and extrusion into strips. The strips were then dried at 120°C for 15 hours and calcined at 500°C for 6 hours to obtain the calcined product. In the seventh step, the calcined product was crushed and sieved to 10 to 20 mesh. A zinc nitrate solution was prepared according to the ratio of 5% zinc oxide impregnation and slowly added dropwise to the 10 to 20 mesh calcined product. The product was impregnated at room temperature for 24 hours. After impregnation, the product was dried at 120°C for 15 hours and calcined at 500°C for 6 hours to obtain a catalytic gasoline olefin aromatization catalyst, which was labeled A-1.

[0042] Example 12: 10g of industrial ZSM-5 molecular sieve (of which the mass percentage of silicon and aluminum is 90%) was mixed evenly with 120g of 0.15mol / L NaOH solution, stirred at 60℃ for 4h, washed with deionized water, dried at 80℃ for 10h, and calcined at 520℃ for 2h to obtain industrial modified ZSM-5 molecular sieve.

[0043] The catalytic gasoline olefin aromatization catalyst was prepared according to the following method: First, sodium aluminate, silica sol, and sodium hydroxide were mixed uniformly in a molar ratio of 1:90:10, and then industrially modified ZSM-5 molecular sieve was added, with the weight of the industrially modified ZSM-5 molecular sieve accounting for 10% of the weight of the added silica; the mixture was stirred at 20°C for 6 hours to obtain a first gel mixture; Second, the first gel mixture was placed in a reaction vessel lined with polytetrafluoroethylene and subjected to hydrothermal crystallization at 100°C for 24 hours in an oven to obtain the first stage of hydrothermal crystallization product; Third, hydrothermal crystallization was carried out at 160°C for 60 hours to obtain the second stage of hydrothermal crystallization product; Fourth, after crystallization, the mixture was cooled, washed, dried at 120°C for 12 hours, and then calcined at 520°C for 4 hours to obtain a sodium-type ZSM-5 molecular sieve with a stepped pore structure; Fifth, the sodium-type ZSM-5 molecular sieve with a stepped pore structure was placed in a 1mol... In a / L ammonium chloride solution, the molecular sieve to ammonium chloride solution was in a weight ratio of 1:10. The mixture was exchanged at 90℃ for 3 hours, followed by washing, drying, and calcination to obtain a hydrogen-form ZSM-5 molecular sieve with a stepped pore structure. In the sixth step, the hydrogen-form ZSM-5 molecular sieve powder with a stepped pore structure was mixed evenly with boehmite at a mass percentage of 50%:50%, then 53% dilute nitric acid was added dropwise for kneading, extruded into strips, and dried at 120℃ for 15 hours. The product was calcined at 500℃ for 6 hours to obtain the calcined product. In the seventh step, the calcined product was crushed and sieved to 10 to 20 mesh. A zinc nitrate-nickel nitrate solution was prepared according to the ratio of 5% zinc oxide and 8% nickel oxide. The solution was slowly added dropwise to the 10 to 20 mesh calcined product and impregnated at room temperature for 24 hours. After impregnation, the product was dried at 120℃ for 15 hours and then calcined at 500℃ for 6 hours to obtain the catalytic gasoline olefin aromatization catalyst, which was labeled as A-2.

[0044] Example 13: 10g of industrial ZSM-5 molecular sieve (of which the mass percentage of silicon and aluminum is 90%) was mixed evenly with 120g of 0.15mol / L NaOH solution, stirred at 60℃ for 4h, washed with deionized water, dried at 80℃ for 10h, and calcined at 520℃ for 2h to obtain industrial modified ZSM-5 molecular sieve.

[0045] The catalytic gasoline olefin aromatization catalyst was prepared according to the following method: First, sodium aluminate, industrial silica gel, and sodium hydroxide were mixed uniformly in a molar ratio of 1:90:15, and then industrial modified ZSM-5 molecular sieve was added, with the weight of the industrial modified ZSM-5 molecular sieve accounting for 5% of the weight of the added silica. The mixture was stirred at 20°C for 12 hours to obtain a first gel mixture. Second, the first gel mixture was placed in a reaction vessel lined with polytetrafluoroethylene and subjected to hydrothermal crystallization at 100°C for 36 hours in an oven to obtain the first stage of hydrothermal crystallization product. Third, hydrothermal crystallization was carried out at 170°C for 24 hours to obtain the second stage of hydrothermal crystallization product. Fourth, after crystallization, the mixture was cooled, washed, dried at 120°C for 12 hours, and then calcined at 520°C for 4 hours to obtain a sodium-type ZSM-5 molecular sieve with a stepped pore structure. Fifth, the sodium-type ZSM-5 molecular sieve with a stepped pore structure was placed in a 1mol / L... In an ammonium chloride solution of L, the weight ratio of molecular sieve to ammonium chloride solution is 1:12. The mixture is exchanged at 85℃ for 2 hours, followed by washing, drying, and calcination to obtain a hydrogen-form ZSM-5 molecular sieve with a stepped pore structure. In the sixth step, the hydrogen-form ZSM-5 molecular sieve powder with a stepped pore structure is mixed evenly with boehmite at a mass percentage of 50%:50%, then 5% dilute nitric acid is added dropwise for kneading, extruded into strips, and dried at 120℃ for 15 hours. The product was calcined at 00℃ for 6 hours to obtain the calcined product. In the seventh step, the calcined product was crushed and sieved to 10 to 20 mesh. An ammonium molybdate-zinc nitrate solution was prepared according to the ratio of 10% molybdenum oxide and 10% zinc oxide. The solution was slowly added dropwise to the calcined product at 10 to 20 mesh and impregnated at room temperature for 48 hours. After impregnation, the product was dried at 120℃ for 15 hours and then calcined at 500℃ for 6 hours to obtain the catalytic gasoline olefin aromatization catalyst, which was labeled as A-3.

[0046] Example 14: 10g of industrial ZSM-5 molecular sieve (of which the mass percentage of silicon and aluminum is 120%) was mixed with 120g of 0.15mol / L NaOH solution, stirred at 60℃ for 4h, washed with deionized water, dried at 80℃ for 10h, and calcined at 520℃ for 2h to obtain industrial modified ZSM-5 molecular sieve.

[0047] The catalytic gasoline olefin aromatization catalyst was prepared according to the following method: First, alumina, silica sol, and sodium acetate were mixed uniformly in a molar ratio of 1:120:15, and then industrially modified ZSM-5 molecular sieve was added, with the weight of the industrially modified ZSM-5 molecular sieve accounting for 4% of the weight of the added silica; the mixture was stirred at 20°C for 12 hours to obtain a first gel mixture; Second, the first gel mixture was placed in a reaction vessel lined with polytetrafluoroethylene and subjected to hydrothermal crystallization at 100°C for 24 hours in an oven to obtain the first stage of hydrothermal crystallization product; Third, hydrothermal crystallization was carried out at 170°C for 36 hours to obtain the second stage of hydrothermal crystallization product; Fourth, after crystallization, the mixture was cooled, washed, dried at 120°C for 12 hours, and then calcined at 520°C for 4 hours to obtain a sodium-type ZSM-5 molecular sieve with a stepped pore structure; Fifth, the sodium-type ZSM-5 molecular sieve with a stepped pore structure was placed in a 1mol... In a / L ammonium chloride solution, the weight ratio of molecular sieve to ammonium chloride solution is 1:10. The mixture is exchanged at 85℃ for 4 hours, then washed, dried, and calcined to obtain a hydrogen-form ZSM-5 molecular sieve with a stepped pore structure. In the sixth step, the hydrogen-form ZSM-5 molecular sieve powder with a stepped pore structure is mixed evenly with boehmite at a mass percentage ratio of 70%:30%, then 5% dilute nitric acid is added dropwise for kneading, extruded into strips, and dried at 120℃ for 15 hours. The product was calcined at 500℃ for 6 hours to obtain the calcined product. In the seventh step, the calcined product was crushed and sieved to 10 to 20 mesh. An ammonium molybdate-cobalt nitrate solution was prepared according to the ratio of 8% molybdenum oxide and 5% cobalt oxide. The solution was slowly added dropwise to the 10 to 20 mesh calcined product and impregnated at room temperature for 48 hours. After impregnation, the product was dried at 120℃ for 15 hours and then calcined at 500℃ for 6 hours to obtain the catalytic gasoline olefin aromatization catalyst, which was labeled as A-4.

[0048] Example 15: 10g of industrial ZSM-5 molecular sieve (of which the mass percentage of silicon and aluminum is 60%) was mixed evenly with 100g of 0.10mol / L NaOH solution, stirred at 60℃ for 4h, washed with deionized water, dried at 80℃ for 10h, and calcined at 520℃ for 2h to obtain industrial modified ZSM-5 molecular sieve.

[0049] The catalytic gasoline olefin aromatization catalyst was prepared according to the following method: First, sodium aluminate, ethyl silicate, and sodium hydroxide were mixed uniformly in a molar ratio of 1:60:10, and then industrially modified ZSM-5 molecular sieve was added, with the weight of the industrially modified ZSM-5 molecular sieve accounting for 70% of the weight of the added silica; the mixture was stirred at 20°C for 12 hours to obtain a first gel mixture; Second, the first gel mixture was placed in a reaction vessel lined with polytetrafluoroethylene and subjected to hydrothermal crystallization at 120°C for 24 hours in an oven to obtain the first stage of hydrothermal crystallization product; Third, hydrothermal crystallization was carried out at 160°C for 48 hours to obtain the second stage of hydrothermal crystallization product; Fourth, after crystallization, the mixture was cooled, washed, dried at 120°C for 12 hours, and then calcined at 520°C for 4 hours to obtain a sodium-type ZSM-5 molecular sieve with a stepped pore structure; Fifth, the sodium-type ZSM-5 molecular sieve with a stepped pore structure was placed in a 1 mol / L chlorine solution... In the ammonium chloride solution, the weight ratio of molecular sieve to ammonium chloride solution is 1:10. The mixture is exchanged at 80℃ for 4 hours, followed by washing, drying, and calcination to obtain a hydrogen-form ZSM-5 molecular sieve with a stepped pore structure. In the sixth step, the hydrogen-form ZSM-5 molecular sieve powder with a stepped pore structure is mixed evenly with alumina powder at a mass percentage ratio of 40%:60%. Then, 5% dilute nitric acid is added dropwise for kneading, extruding into strips, and drying at 120℃ for 15 hours, followed by further drying at 500℃. The product was calcined for 6 hours to obtain the calcined product. In the seventh step, the calcined product was crushed and sieved to 10 to 20 mesh. A zinc nitrate-nickel nitrate-cobalt nitrate solution was prepared according to the ratio of 12% zinc oxide, 5% nickel oxide, and 3% cobalt oxide. The solution was slowly added dropwise to the calcined product of 10 to 20 mesh and impregnated at room temperature for 24 hours. After impregnation, the product was dried at 120°C for 15 hours and then calcined at 500°C for 6 hours to obtain the catalytic gasoline olefin aromatization catalyst, which was labeled as A-5.

[0050] Example 16: 10g of industrial ZSM-5 molecular sieve (of which the mass percentage of silicon and aluminum is 90%) was mixed evenly with 120g of 0.15mol / L NaOH solution, stirred at 60℃ for 4h, washed with deionized water, dried at 80℃ for 10h, and calcined at 520℃ for 2h to obtain industrial modified ZSM-5 molecular sieve.

[0051] The catalytic gasoline olefin aromatization catalyst was prepared according to the following method: First, sodium aluminate, industrial silica gel, and sodium hydroxide were mixed uniformly in a molar ratio of 1:90:9, and then industrial modified ZSM-5 molecular sieve was added, with the weight of the industrial modified ZSM-5 molecular sieve accounting for 6% of the weight of the added silica. The mixture was stirred at 20°C for 6 hours to obtain a first gel mixture. Second, the first gel mixture was placed in a reaction vessel lined with polytetrafluoroethylene and subjected to hydrothermal crystallization at 100°C for 30 hours in an oven to obtain the first stage of hydrothermal crystallization product. Third, hydrothermal crystallization was carried out at 180°C for 48 hours to obtain the second stage of hydrothermal crystallization product. Fourth, after crystallization, the mixture was cooled, washed, dried at 120°C for 12 hours, and then calcined at 520°C for 4 hours to obtain a sodium-type ZSM-5 molecular sieve with a stepped pore structure. Fifth, the sodium-type ZSM-5 molecular sieve with a stepped pore structure was placed in a 1 mol / L ammonium chloride solution. The molecular sieve and ammonium chloride solution were exchanged at 85℃ for 4 hours by weight ratio of 1:10. After washing, drying, and calcination, hydrogen-form ZSM-5 molecular sieve with a stepped pore structure was obtained. In the sixth step, the hydrogen-form ZSM-5 molecular sieve powder with a stepped pore structure was mixed evenly with alumina powder and silica powder in a mass percentage ratio of 40%:40%:20%. Then, 5% dilute nitric acid was added dropwise for kneading, extruded into strips, dried at 120℃ for 15 hours, and then heated at 500℃. The product was calcined for 6 hours under the given conditions to obtain the calcined product. In the seventh step, the calcined product was crushed and sieved to 10 to 20 mesh. A zinc nitrate-ammonium molybdate-lanthanum nitrate solution was prepared according to the ratio of 8% zinc oxide, 5% molybdenum oxide, and 1% lanthanum oxide. The solution was slowly added dropwise to the 10 to 20 mesh calcined product and impregnated at room temperature for 24 hours. After impregnation, the product was dried at 120°C for 15 hours and then calcined at 500°C for 6 hours to obtain the catalytic gasoline olefin aromatization catalyst, which was labeled as A-6.

[0052] Example 17: 10g of industrial ZSM-5 molecular sieve (of which the mass percentage of silicon and aluminum is 60%) was mixed evenly with 120g of 0.15mol / L NaOH solution, stirred at 60℃ for 4h, washed with deionized water, dried at 80℃ for 10h, and calcined at 520℃ for 2h to obtain industrial modified ZSM-5 molecular sieve.

[0053] The catalytic gasoline olefin aromatization catalyst was prepared according to the following method: First, sodium aluminate, industrial silica gel, and sodium hydroxide were mixed uniformly in a molar ratio of 1:60:8, and then industrial modified ZSM-5 molecular sieve was added, with the weight of the industrial modified ZSM-5 molecular sieve accounting for 5% of the weight of the added silica. The mixture was stirred at 20°C for 12 hours to obtain a first gel mixture. Second, the first gel mixture was placed in a reaction vessel lined with polytetrafluoroethylene and subjected to hydrothermal crystallization at 100°C for 36 hours in an oven to obtain the first stage of hydrothermal crystallization product. Third, hydrothermal crystallization was carried out at 160°C for 36 hours to obtain the second stage of hydrothermal crystallization product. Fourth, after crystallization, the mixture was cooled, washed, dried at 120°C for 12 hours, and then calcined at 520°C for 4 hours to obtain a sodium-type ZSM-5 molecular sieve with a stepped pore structure. Fifth, the sodium-type ZSM-5 molecular sieve with a stepped pore structure was placed in a 1 mol / L chloride solution. In an ammonium solution, the weight ratio of molecular sieve to ammonium chloride solution is 1:10. The mixture is exchanged at 85℃ for 4 hours, followed by washing, drying, and calcination to obtain a hydrogen-form ZSM-5 molecular sieve with a stepped pore structure. In the sixth step, the hydrogen-form ZSM-5 molecular sieve powder with a stepped pore structure is mixed evenly with boehmite at a mass percentage ratio of 40%:60%. Then, 5% dilute nitric acid is added dropwise for kneading, extruding into strips, drying at 120℃ for 15 hours, and then further drying at 500℃. The product was calcined for 6 hours to obtain the calcined product. In the seventh step, the calcined product was crushed and sieved to 10 to 20 mesh. A zinc nitrate-nickel nitrate-ammonium molybdate solution was prepared according to the ratio of 8% zinc oxide, 5% nickel oxide, and 3% molybdenum oxide. The solution was slowly added dropwise to the 10 to 20 mesh calcined product and impregnated at room temperature for 24 hours. After impregnation, the product was dried at 120°C for 15 hours and then calcined at 500°C for 6 hours to obtain the catalytic gasoline olefin aromatization catalyst, which was labeled as A-7.

[0054] Example 18: 10g of industrial ZSM-5 molecular sieve (of which the mass percentage of silicon and aluminum is 90%) was mixed evenly with 100g of 0.1mol / L NaOH solution, stirred at 60℃ for 4h, washed with deionized water, dried at 80℃ for 10h, and calcined at 500℃ for 2h to obtain industrial modified ZSM-5 molecular sieve.

[0055] The catalytic gasoline olefin aromatization catalyst was prepared according to the following method: First, sodium aluminate, silica sol, and sodium hydroxide were mixed uniformly in a molar ratio of 1:100:10, and then industrially modified ZSM-5 molecular sieve was added, with the weight of the industrially modified ZSM-5 molecular sieve accounting for 10% of the weight of the added silica. The mixture was stirred at 20°C for 6 hours to obtain a first gel mixture. Second, the first gel mixture was placed in a reaction vessel lined with polytetrafluoroethylene and subjected to hydrothermal crystallization at 100°C for 24 hours in an oven to obtain the first stage of hydrothermal crystallization product. Third, hydrothermal crystallization was carried out at 180°C for 36 hours to obtain the second stage of hydrothermal crystallization product. Fourth, after crystallization, the mixture was cooled, washed, dried at 120°C for 12 hours, and then calcined at 520°C for 4 hours to obtain a sodium-type ZSM-5 molecular sieve with a stepped pore structure. Fifth, the sodium-type ZSM-5 molecular sieve with a stepped pore structure was placed in a 1 mol / L ammonium chloride solution. The molecular sieve and ammonium chloride solution were exchanged at 85℃ for 4 hours by weight ratio of 1:10. After washing, drying, and calcination, hydrogen-form ZSM-5 molecular sieve with a stepped pore structure was obtained. In the sixth step, the hydrogen-form ZSM-5 molecular sieve powder with a stepped pore structure was mixed evenly with alumina powder and silica powder in a mass percentage ratio of 50%:20%:30%. Then, 5% dilute nitric acid was added dropwise for kneading, extruded into strips, dried at 120℃ for 15 hours, and then heated at 500℃. The product was calcined for 6 hours under the given conditions to obtain the calcined product. In the seventh step, the calcined product was crushed and sieved to 10 to 20 mesh. An ammonium molybdate-cobalt nitrate-gallium nitrate solution was prepared by impregnating 8% molybdenum oxide, 3% cobalt oxide, and 1% gallium oxide. The solution was slowly added dropwise to the 10 to 20 mesh calcined product and impregnated at room temperature for 24 hours. After impregnation, the product was dried at 120°C for 15 hours and then calcined at 500°C for 6 hours to obtain the catalytic gasoline olefin aromatization catalyst, which was labeled as A-8.

[0056] The catalytic gasoline de-olefin aromatization catalysts prepared in Examples 11 to 18 of this invention were used in the catalytic gasoline desulfurization aromatization reaction. 100g of catalyst was loaded into a fixed-bed evaluation device, and the feedstock was catalytic gasoline. The properties of the feedstock catalytic gasoline are shown in Table 1. Using the above catalyst and catalytic gasoline feedstock, the catalytic gasoline desulfurization aromatization reaction was evaluated in a fixed-bed evaluation device. The catalyst loading was 100g, the reaction temperature was 300℃ to 360℃, the reaction pressure was 0MPa to 2MPa, and the WHSV was 0.5 h⁻¹. -1 Up to 2 hours -1The reaction results are shown in Table 2. As can be seen from Table 2, the catalytic gasoline olefin aromatization catalyst samples A-1 to A-8 prepared in this invention have dual functions of sulfur resistance and aromatization. They exhibit good sulfur resistance and aromatization performance in the catalytic gasoline olefin aromatization reaction, with an olefin content of <16% and an aromatic hydrocarbon content of >40%. The aromatized product can be used as a reforming feedstock.

[0057] In summary, the synthesis process of this invention is simple, low-cost, and environmentally friendly. When used in the catalytic aromatization reaction of gasoline, it has dual functions of sulfur resistance and aromatization, and achieves a high degree of olefin aromatization. The product can be used as a reforming feedstock to achieve the purpose of increasing aromatics in chemical products.

[0058] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

[0059]

Claims

1. The application of a catalyst for catalytic gasoline olefin de-aromatization in the catalytic gasoline olefin de-aromatization reaction, characterized in that... The catalytic gasoline olefin de-aromatization catalyst was prepared according to the following method: First, 10g of industrial ZSM-5 molecular sieve was mixed evenly with 100g of 0.1mol / L NaOH solution, wherein the mass percentage of silicon and aluminum was 120. The mixture was stirred at 60℃ for 4h, washed with deionized water, dried at 80℃ for 10h, and calcined at 500℃ for 2h to obtain industrial modified ZSM-5 molecular sieve. Sodium aluminate, tetraethyl orthosilicate, and sodium acetate were mixed evenly in a molar ratio of 1:120:10, and then industrial modified ZSM-5 molecular sieve was added, with the weight of industrial modified ZSM-5 molecular sieve accounting for 10% of the weight of silicon dioxide added. The mixture was stirred at 20℃ for 6h to obtain the first gel mixture. The second step involves loading the first gel mixture into a reaction vessel lined with polytetrafluoroethylene, placing it in an oven, and hydrothermally crystallizing it at 100°C for 12 hours to obtain the first hydrothermal crystallization product. The third step is to perform hydrothermal crystallization at 160℃ for 48 hours to obtain the second hydrothermal crystallization product. The fourth step is to cool down and wash the crystallization process, dry it at 120℃ for 12 hours, and then calcine it at 520℃ for 4 hours to obtain sodium-type ZSM-5 molecular sieve with a stepwise pore structure. The fifth step involves placing the sodium-type ZSM-5 molecular sieve with a stepped pore structure into a 1 mol / L ammonium chloride solution, with a weight ratio of 1:10 between the molecular sieve and the ammonium chloride solution. The sieve is then exchanged at 80°C for 3 hours. After washing, drying, and calcining, the hydrogen-type ZSM-5 molecular sieve with a stepped pore structure is obtained. Step 6: Mix the hydrogen-type ZSM-5 molecular sieve dry powder with a tiered pore structure and boehmite in a mass percentage ratio of 60%:40%, then add 3% dilute nitric acid dropwise to knead and extrude into strips. Dry at 120°C for 15 hours and calcine at 500°C for 6 hours to obtain the calcined product. Step 7: Crush and sieve the calcined product to 10 to 20 mesh, prepare a zinc nitrate solution according to the ratio of 5% zinc oxide impregnation, slowly add it dropwise to the calcined product to 10 to 20 mesh, impregnate at room temperature for 24 hours, after impregnation, dry at 120℃ for 15 hours, and calcine at 500℃ for 6 hours to obtain the catalytic gasoline olefin aromatization catalyst.

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