A ZSM-5 molecular sieve catalyst, its preparation method and application

Abstract

The present invention discloses a ZSM-5 molecular sieve catalyst, a preparation method thereof and an application thereof. The properties of the catalyst are as follows: the ratio of the amount of framework aluminum at the intersection of the straight pore channels and the sinusoidal pore channels to the amount of framework aluminum in the straight pore channels and in the sinusoidal pore channels is 1.4:1 to 10:1, and the micropore pore volume accounts for 70% to 92% of the total pore volume. When the catalyst of the present invention is used in the reaction of catalytic cracking of olefins to produce propylene and ethylene, it has the characteristics of low reaction hydrogen transfer index, high stability, high raw material olefin conversion rate, and high selectivity of the products propylene and ethylene.

Description

Technical Field

[0001] The invention relates to the field of catalytic cracking, and in particular to a ZSM-5 molecular sieve catalyst and a preparation method thereof, as well as application in catalytic cracking of olefins to increase the production of propylene and ethylene. Background Art

[0002] Propylene and ethylene are important basic raw materials for the petrochemical industry. Driven by the rapid growth in demand for polyolefins and their derivatives, the demand for propylene and ethylene has continued to be strong and has grown at a relatively fast rate in recent years. Therefore, they are considered to be products with great market potential. Mixed C4 and above olefins are by-products of ethylene plants and FCC units in refineries. They can usually only be used as low value-added products such as liquefied gas fuel. Further processing them into propylene and ethylene and making full use of this considerable amount of valuable olefin resources will undoubtedly have a significant role in promoting economic and technological development. Olefin catalytic cracking technology can convert raw materials containing olefin substances into ethylene and propylene. With the continuous innovation and development of development technology, olefin catalytic cracking technology for increasing the production of propylene and ethylene has achieved remarkable results, greatly improving production efficiency, and has a profound impact on the development of the petrochemical industry, which will help promote the innovation and development of subsequent petrochemical production technology. Catalysts are the core technology in olefin catalytic cracking reactions. Many scholars have conducted extensive research using various preparation methods. The research focuses on preparing catalysts with high activity and selectivity, improving the selectivity of molecular sieves by regulating acid properties and optimizing the control of molecular sieve pore structure, and reducing the formation of by-products and carbon deposits. Modification elements, loading amount and modification methods will directly affect catalytic performance and product distribution.

[0003] The catalyst used for olefin cracking, the active component is a molecular sieve such as hydrogen ZSM-5, ZSM-11 or SAPO-34, and the inert gas as a heat carrier and diluent is of great benefit to the improvement of various indicators of this reaction. However, the presence of water in the reaction is not conducive to the long-term use of the catalyst. Usually, acidic molecular sieve catalysts will undergo serious skeleton dealumination under high-temperature hydrothermal conditions, which will rapidly reduce the catalyst acid density and cause irreversible loss of catalyst activity. At the same time, due to the strong acidity of the molecular sieve, while olefin cracking to generate propylene and ethylene, side reactions such as olefin superposition chain growth, hydrogen transfer and aromatization will occur, and even coking will occur in the pores of the molecular sieve catalyst, covering the reaction active center, causing the catalyst to deactivate quickly. EP0109059A1 discloses a method of converting C4-C 12 A method for preparing propylene by cracking olefins, wherein ZSM-5 or ZSM-11 molecular sieve is used as a catalyst. 12A method for producing propylene and ethylene by olefin cracking, wherein the active component of the catalyst used is a ZSM-5 molecular sieve without proton acid and containing a Group IB metal. The olefin cracking catalysts reported in the above-mentioned literature all have defects to varying degrees, such as poor product selectivity, poor catalyst stability, easy coking deactivation, and inability to meet long-term operation, so it is difficult to realize industrialization. SUMMARY OF THE INVENTION

[0004] The technical problem to be solved by the present invention is the poor stability of the existing catalysts for olefin catalytic cracking to produce propylene and ethylene and the low selectivity of diolefins. The present invention provides a ZSM-5 molecular sieve catalyst and its preparation method, as well as the application of the catalyst in olefin catalytic cracking to increase the production of propylene and ethylene. When the catalyst of the present invention is used in the reaction of olefin catalytic cracking to produce propylene and ethylene, it has the characteristics of low reaction hydrogen transfer index, high stability, high raw material olefin conversion rate, and high selectivity of product propylene and ethylene.

[0005] In the first aspect of the present invention, a ZSM-5 molecular sieve catalyst is provided, and the properties of the catalyst are as follows: the ratio of the framework aluminum amount at the intersection of the straight channels and the sinusoidal channels to the framework aluminum amounts in the straight channels and the sinusoidal channels is 1.4:1 to 10:1, and the micropore pore volume accounts for 70% to 92% of the total pore volume.

[0006] In the above technical solution, the properties of the catalyst are as follows: the ratio of the framework aluminum amount at the intersection of the straight channels and the sinusoidal channels to the framework aluminum amounts in the straight channels and the sinusoidal channels is preferably 1.4:1 to 4:1.

[0007] In the above technical solution, in the range of the ratio of the framework aluminum amount at the intersection of the straight channels and the sinusoidal channels to the framework aluminum amounts in the straight channels and the sinusoidal channels in the catalyst, non-limiting specific point values can be 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, 3.2:1, 3.5:1, 4.0:1, etc.

[0008] In the above technical solution, the total pore volume of the catalyst is 0.01 to 1.2 mL / g, preferably 0.1 to 0.8 mL / g.

[0009] In the above technical solution, the ratio of the micropore pore volume to the total pore volume, non-limiting specific point values can be 70%, 72%, 73%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88%, 90%, 92%, etc.

[0010] In the above technical solution, the ZSM-5 molecular sieve catalyst, in parts by weight, comprises the following components:

[0011] a) 90 to 100 parts of hydrogen-type ZSM-5 molecular sieve, preferably 92 to 99 parts;

[0012] b) 0 to 5 parts of rare earth element, preferably 0.5 to 3.0 parts;

[0013] c) 0 to 5 parts of alkaline earth metal element, preferably 0.5 to 5.0 parts.

[0014] In the above technical solution, the molar ratio of silicon to aluminum SiO2 / Al2O3 of the hydrogen-type ZSM-5 molecular sieve is 80 to 1500, preferably 80 to 1000.

[0015] In the above technical solution, the rare earth element is selected from at least one of La, Ce, Pr, and Nd.

[0016] In the above technical solution, the alkaline earth metal element is selected from at least one of Mg, Ca, Sr, and Ba.

[0017] In the above technical solution, the ZSM-5 molecular sieve catalyst is a binderless ZSM-5 molecular sieve catalyst. Further, based on the mass of the catalyst, the mass content of the binder is below 5%, preferably below 2%, and more preferably below 0.5%.

[0018] In the above technical solution, the ZSM-5 molecular sieve catalyst is an olefin catalytic cracking catalyst.

[0019] The second aspect of the present invention provides a preparation method of the above ZSM-5 molecular sieve catalyst, comprising the following steps:

[0020] (1) Prepare ZSM-5 molecular sieve raw powder;

[0021] (2) Knead and mold the molecular sieve raw powder obtained in step (1) with a binder, and dry it to obtain a catalyst precursor;

[0022] (3) Perform third hydrothermal crystallization and ammonium exchange on the catalyst precursor obtained in step (2) in the presence of a third template agent to obtain a ZSM-5 molecular sieve catalyst.

[0023] In the above technical solution, optionally, step (4) may further be included, specifically as follows:

[0024] The hydrogen-type ZSM-5 molecular sieve obtained in step (3) is loaded with rare earth metal and / or alkaline earth metal to obtain a metal-containing ZSM-5 molecular sieve catalyst.

[0025] In the above technical solution, the preparation method of the ZSM-5 molecular sieve raw powder in step (1) includes:

[0026] (11) Mix the first template agent, the first aluminum source, the silicon source, the first alkali source and water, and carry out the first hydrothermal crystallization;

[0027] (12) Mix the second aluminum source, the second template agent, the second alkali source and the mixture obtained after crystallization in step (11), and carry out the second hydrothermal crystallization to obtain the ZSM-5 molecular sieve raw powder.

[0028] In the above technical solution, in step (11), the first template agent is at least one of tetrapropylammonium bromide, tetrapropylammonium hydroxide, tetraethylammonium chloride, and ammonia water; the first aluminum source is at least one of aluminum nitrate, aluminum sulfate, or aluminum phosphate; the silicon source is at least one of water glass, tetraethyl orthosilicate, or silica sol; the first alkali source is at least one of sodium hydroxide and potassium hydroxide. The first hydrothermal crystallization can be carried out under the autogenous pressure generated in a stainless steel autoclave. The water is preferably deionized water. The conditions for the first hydrothermal crystallization are as follows: the crystallization temperature is 80-150 °C, and the crystallization time is 2-10 h. In step (11), the first template agent is calculated as NH4 + calculated, the first aluminum source is calculated as Al2O3, the silicon source is calculated as SiO2, the first alkali source is calculated as OH - calculated, and the water is calculated as H2O. The molar ratio is: NH4 + :Al2O3:SiO2:OH - :H2O = 0.2-0.3:0.0005-0.001:1:0.2-0.4:15-20.

[0029] In the above technical solution, in step (12), the second aluminum source is at least one of potassium alum or sodium metaaluminate. The potassium alum can be a hydrate, such as potassium alum dodecahydrate. The second template agent is at least one of n-butylamine, hexamethylenediamine, and pyridine. The second alkali source is at least one of sodium hydroxide and potassium hydroxide. The total addition amount of the silicon source in step (11), the second aluminum source in step (12), and the first aluminum source in step (11), calculated as SiO2 / Al2O3, has a molar ratio of 80-1500, preferably 80-1000. The addition amount of the second aluminum source in step (12) calculated as Al2O3 accounts for more than 30%, preferably more than 40%, of the total mass of the second aluminum source in step (12) and the first aluminum source in step (11) calculated as Al2O3.

[0030] In the above technical solution, the second template agent and the second aluminum source in step (12), calculated as NH4 +Based on Al2O3, the molar ratio is 200 - 500:1. The second base source is used to control the pH value of the system to be 8 - 10. The conditions for the second hydrothermal crystallization are as follows: the crystallization temperature is 120 - 200 °C, and the crystallization time is 10 - 100 h. The second hydrothermal crystallization can be carried out under the autogenous pressure generated in a stainless steel autoclave.

[0031] In the above technical solution, the product obtained after the second hydrothermal crystallization can be washed, dried, and calcined to obtain the ZSM-5 molecular sieve raw powder. The washing can be carried out with deionized water. The drying conditions are as follows: the drying temperature is 80 - 100 °C, and the drying time is 10 - 20 h. The calcination conditions are as follows: the calcination temperature is 500 - 650 °C, and the calcination time is 8 - 15 h.

[0032] In the above technical solution, in step (2), the binder is a silicon compound or a silicon compound and an aluminum compound. The aluminum compound is selected from at least one of alumina and aluminum sol, and the silicon compound is selected from at least one of fumed silica and silica sol. In the binder, based on silicon dioxide for the silicon compound and based on alumina for the aluminum compound, the amount of the silicon compound can account for 10% - 100%, or can also account for 50% - 100%. The addition amount of the binder, based on the sum of the masses of alumina and silica, accounts for 8% - 45% of the total mass of the molecular sieve raw powder and the binder, preferably 10% - 40%. The shaping in step (2) can adopt conventional shaping methods, such as extrusion molding, etc. In step (2), according to the shaping requirements, an appropriate amount of water can be added. The drying conditions are as follows: the drying temperature is 80 - 120 °C, and the drying time is 5 - 10 h.

[0033] In the above technical solution, in step (3), the third template agent is at least one of ammonia water, ethylamine, ethylenediamine, triethylamine, n-butylamine, hexamethylenediamine, tetrapropylammonium bromide, or tetrapropylammonium hydroxide. The third hydrothermal crystallization is to subject the catalyst precursor obtained in step (2) to crystallization in the vapor containing the third template agent. The mass ratio of the third template agent to the catalyst precursor is 1 - 3:1, and the crystallization is carried out at 130 - 200 °C for 20 - 100 h. The third hydrothermal crystallization adopts the gas-solid transformation crystallization method, that is, the catalyst precursor is placed on the intermediate mesh in the crystallization kettle, and the aqueous solution containing the third template agent is placed below the intermediate mesh. Under the crystallization conditions, the vapor formed by the aqueous solution containing the third template agent below is used to carry out the transformation crystallization treatment on the catalyst precursor. The third hydrothermal crystallization can be carried out under the autogenous pressure generated in a stainless steel autoclave. The mass ratio of the third template agent to water in the aqueous solution of the third template agent is 1 - 2∶1.

[0034] In the above technical solution, the product obtained after the third hydrothermal crystallization can be washed, dried, and calcined. The drying conditions are as follows: the drying temperature is 80-100°C, and the drying time is 10-20 h. The calcination conditions are as follows: the calcination temperature is 450-600°C, and the calcination time is 5-10 h.

[0035] In the above technical solution, the ammonium exchange in step (3) is to place the product obtained after the crystallization of the catalyst precursor in an ammonium salt aqueous solution for ammonium exchange, washing, and drying. The ammonium salt is selected from one or more of ammonium chloride, ammonium nitrate, and ammonium sulfate. The mass content of the ammonium salt in the ammonium salt aqueous solution is 5%-10%. The temperature of the ammonium exchange is 80-90°C; the number of ammonium exchange times can be 3-6 times. The product obtained after ammonium exchange is calcined; the calcination conditions are as follows: the calcination temperature is 500-600°C, and the calcination time is 4-8 h.

[0036] In the above technical solution, step (4) is an optional step and is determined according to the catalyst composition. The loading method of rare earth metals and / or alkaline earth metals can adopt the impregnation method. Preferably, the catalyst contains rare earth metals and alkaline earth metals, and the loading process is as follows: first, obtain ZSM-5 molecular sieve loaded with rare earth metals, and then obtain ZSM-5 molecular sieve loaded with rare earth metals and alkaline earth metals, which is the metal-containing ZSM-5 molecular sieve catalyst. The impregnation method is preferably the equal-volume impregnation method. The molecular sieve is impregnated in an equal volume in a rare earth metal salt solution or an alkaline earth metal salt solution for 3-10 h, dried at 60-100°C for 10-20 h, and then calcined at 450-600°C for 8-10 h to obtain. In the rare earth metal salt solution, the weight concentration of the rare earth metal is 0.2%-5%. The rare earth element is selected from at least one of La, Ce, Pr, and Nd; in the alkaline earth metal salt solution, the weight concentration of the alkaline earth metal is 0.2%-5%. The alkaline earth metal element is selected from at least one of Mg, Ca, Sr, and Ba.

[0037] The third aspect of the present invention provides an application of the above ZSM-5 molecular sieve catalyst in the catalytic cracking of olefins to produce propylene and ethylene.

[0038] In the above technical solution, the process of catalytic cracking of olefins to produce propylene and ethylene is as follows: the olefin raw material contacts with the above ZSM-5 molecular sieve catalyst for reaction to obtain propylene and ethylene products.

[0039] In the above technical solution, at least one of C4-C6 olefins is used as the raw material, and the reaction conditions are as follows: the reaction temperature is 400-600°C, preferably 420-580°C, the reaction pressure is 0-0.3 MPa, preferably 0.01-0.2 MPa, and the weight hourly space velocity is 1-50 h -1 , preferably 2-40 h -1 .

[0040] In the above technical solution, raw materials generate propylene and ethylene through the catalyst bed layer, and the reaction hydrogen transfer index is lower than 9.6, preferably lower than 7; the hydrogen transfer index is the mass ratio of the yields of propane and propylene in the product.

[0041] In the prior art, in the process of olefin catalytic cracking to increase the production of propylene and ethylene, there are problems of low selectivity of propylene and ethylene and poor catalyst stability. This is mainly because the olefin cracking reaction network is complex, including unimolecular cracking, bimolecular cracking and trimolecular cracking reactions. The process involves multiple steps such as olefin isomerization, oligomerization, cracking, dehydrogenation aromatization, hydrogen transfer reaction, alkylation, coking, etc. Among them, the degree of the hydrogen transfer reaction is the key factor affecting the other side reactions and product selectivity. The ordinary ZSM-5 molecular sieve with a low silica-alumina ratio has too many acid centers, which leads to more side reactions, low product selectivity and blockage of the molecular sieve pores by by-products after the reaction, thereby reducing the catalyst activity and finally causing the catalyst deactivation. While the ZSM-5 molecular sieve with a high silica-alumina ratio has fewer active centers and uneven active distribution, resulting in low reaction activity and poor catalyst stability. The inventor has found through research that in the ZSM-5 molecular sieve catalyst, when the amount of framework aluminum at the intersection of the straight channels and the sinusoidal channels is significantly higher than the amount of framework aluminum inside the straight channels and the sinusoidal channels and the appropriate micropore volume ratio, it has good activity and selectivity when used for olefin catalytic cracking to produce propylene and ethylene, and the stability is further increased.

[0042] Compared with the prior art, the present invention has the following technical effects:

[0043] 1. The ZSM-5 molecular sieve catalyst of the present invention has the characteristics that the amount of framework aluminum at the intersection of the straight channels and the sinusoidal channels is significantly higher than the amount of framework aluminum inside the straight channels and the sinusoidal channels, and has an appropriate micropore volume ratio, which greatly improves the utilization rate of the catalyst active centers, so that the products and intermediates generated at the intersection of the cross channels are more likely to diffuse, significantly reducing the occurrence of side reactions and the formation of coke, greatly reducing the reaction hydrogen transfer index, significantly improving the catalyst activity and product selectivity, and further increasing the stability.

[0044] 2. In the preparation process of the ZSM-5 molecular sieve catalyst of the present invention, especially in the synthesis process of the ZSM-5 molecular sieve raw powder, different aluminum sources and templates are added in batches, and the prepared molecular sieve catalyst has a composite pore structure. After the conversion treatment, the obtained catalyst basically does not contain a binder, and the amount of framework aluminum at the intersection of the straight channels and the sinusoidal channels is significantly higher than the amount of framework aluminum inside the straight channels and the sinusoidal channels, and the micropore volume accounts for 70% - 92% of the total pore volume, which significantly improves the catalyst activity and product selectivity, and further increases the stability.

[0045] 3. The method for catalytic cracking of olefins to produce ethylene and propylene according to the present invention effectively overcomes the disadvantages of high reaction hydrogen transfer index, poor catalyst activity, and low selectivity of propylene and ethylene in the prior art. By using the catalyst of the present invention, the reaction hydrogen transfer index can be reduced to less than 9.6, preferably less than 7. The conversion rate of the raw material olefin is above 71%, and the selectivity of the target products propylene and ethylene exceeds 68%, preferably exceeds 80%. After the reaction proceeds for 75 hours, the activity and selectivity of the catalyst do not change significantly, showing good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is the framework aluminum of the catalyst obtained in Example 1 27 Al nuclear magnetic spectrum;

[0047] Figure 1 Among them, line 1 is the framework aluminum species at the intersection of the straight pore and the sinusoidal pore, line 2 is the framework aluminum species in the straight pore and the sinusoidal pore; line 3 is the original curve before peak splitting;

[0048] Figure 2 is the XRD pattern of the catalyst obtained in Example 1;

[0049] Figure 3 is the framework aluminum of the catalyst obtained in Comparative Example 4 27 Al nuclear magnetic spectrum;

[0050] Figure 3 Among them, line 1 is the framework aluminum species at the intersection of the straight pore and the sinusoidal pore, line 2 is the framework aluminum species in the straight pore and the sinusoidal pore; line 3 is the original curve before peak splitting;

[0051] Figure 4 is the XRD pattern of the catalyst obtained in Comparative Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0052] The present invention will be further described below by way of examples.

[0053] In the present invention, the pore volume is measured on a TriStar 3000 type physical adsorption instrument. After vacuum treatment at 300 °C for 3 hours, it is placed in the tester and liquid nitrogen is added for testing. The Barret-Joyner-Halenda (BJH) model is used to calculate the pore distribution of the sample.

[0054] In the present invention, 27 the instrument used for Al nuclear magnetic characterization is a DSX 300 type nuclear magnetic resonance instrument of Bruker company, 27 the chemical shift of Al refers to Al(H2O)6 in saturated aluminum chloride solution 3+ , and the nuclear magnetic spectrum is obtained under the condition of a magic angle rotation speed of 4 kHz. Among them, the framework aluminum at the intersection of the straight pore and the sinusoidal pore in the catalyst corresponds to27 The peak in the Al nuclear magnetic resonance spectrum with a chemical shift near 54 ppm, and the framework aluminum located in the straight channels and sinusoidal channels corresponds to 27 the peak in the Al nuclear magnetic resonance spectrum with a chemical shift near 56 ppm. The ratio of the amount of framework aluminum at the intersection of the straight channels and the sinusoidal channels to the amount of framework aluminum in the straight channels and sinusoidal channels is based on 27 the ratio of the areas corresponding to the peaks near 54 ppm and 56 ppm in the Al nuclear magnetic resonance spectrum after peak deconvolution.

[0055] In the present invention, the XRD analysis was carried out on a Rigaku D / MAX-1400X type polycrystalline X-ray diffractometer, with a graphite monochromator, Cu Kα radiation, a tube voltage of 40 kV, a tube current of 40 mA, and a scanning speed of 15°·min -1 , and the scanning range 2θ was 5 - 50°.

[0056] In the present invention, the silicon-aluminum molar ratio SiO2 / Al2O3 was calculated after analyzing the elemental composition of the solid sample by using a Magix X type fluorescence spectrometer from Philips Company of the Netherlands, with an operating voltage of 40 kV and an operating current of 40 mA.

[0057] In the examples and comparative examples of the present invention, at least one of C4 - C6 olefins was used as the raw material, and catalytic cracking was carried out to produce ethylene and propylene. Among them, the hydrogen transfer index is the ratio of the yields of propylene and ethylene to propane and ethane in the product, that is, the hydrogen transfer index I = the sum of the masses of the produced propylene and ethylene / the sum of the masses of the produced propane and ethane;

[0058] The conversion rate of the raw material olefin (%) = (1 - the mass of olefin in the product / the mass of olefin in the raw material) × 100%;

[0059] The diene selectivity (%) = the sum of the masses of the produced propylene and ethylene in the product / (the mass of olefin in the raw material - the mass of olefin remaining after the reaction) × 100%.

[0060]

Example 1

[0061] (1) Preparation of ZSM-5 molecular sieve raw powder

[0062] Using tetrapropylammonium bromide as the first template agent, aluminum nitrate as the first aluminum source, silica sol as the silicon source, and sodium hydroxide as the first base source, the molar ratio of tetrapropylammonium bromide based on NH4 + calculated, aluminum nitrate based on Al2O3, silica sol based on SiO2, sodium hydroxide based on OH - calculated, and water based on H2O was: NH4 + :Al2O3:SiO2:OH -:H2O = 0.3:0.001:1:0.2:15. After sufficient mixing and stirring, it was transferred into an autoclave, crystallized at 100 °C for 8 h, and then cooled for standby. According to the total amount of the silicon source, the first aluminum source and the second aluminum source, potassium alum dodecahydrate, the second aluminum source after removing the first aluminum source, was added in a ratio of SiO2 / Al2O3 molar ratio of 300. The second template agent and the second aluminum source were added with n-butylamine, the second template agent, in a ratio of NH4 + / Al2O3 molar ratio of 200:1. It was fully mixed with the above crystallization solution, and the pH was adjusted to 10 with sodium hydroxide, the second base source. Then it was transferred into a stainless-steel autoclave for secondary hydrothermal crystallization at 120 °C for 100 h. The synthesized product was washed with water, dried at 90 °C for 15 h, and calcined at 600 °C for 10 h to obtain the ZSM-5 molecular sieve raw powder.

[0063] (2) Preparation of catalyst precursor

[0064] 100 g of the above ZSM-5 molecular sieve raw powder, 25 g of silica sol containing 40 wt% SiO2 and 0.056 g of alumina were kneaded, extruded into pellets, and dried at 80 °C for 10 h to obtain the catalyst precursor.

[0065] (3) Preparation of hydrogen-form ZSM-5 molecular sieve

[0066] Using ethylamine as the third template agent, a mixture of 30 g of ethylamine and 30 g of distilled water was pre-added into the reaction kettle. 20 g of the above-prepared strip-shaped catalyst precursor was placed above the porous stainless-steel mesh in the reaction kettle, sealed, and subjected to gas-solid phase hydrothermal crystallization at 130 °C for 100 h. After the product was taken out, it was washed with distilled water, dried at 90 °C for 15 h, and then calcined in an air atmosphere at 550 °C for 10 h.

[0067] It was then subjected to ammonium exchange 3 times in a 5 wt% ammonium nitrate solution at 90 °C, dried, and calcined in a muffle furnace at 500 °C for 4 h to obtain the hydrogen-form ZSM-5 molecular sieve.

[0068] (4) Impregnation of metal components

[0069] The obtained hydrogen-form ZSM-5 molecular sieve solid was placed in a 20 g praseodymium nitrate solution with a Pr mass content of 1% for impregnation for 10 h, dried at 100 °C for 10 h, and calcined at 550 °C for 8 h.

[0070] Finally, the above solid was placed in a 20 g magnesium nitrate solution with a Mg weight content of 2% for impregnation for 8 h, dried at 100 °C for 10 h, and calcined at 550 °C for 8 h to obtain the catalyst.

[0071] Through physical adsorption tests, the total pore volume of the catalyst was 0.3 mL / g, and the micropore pore volume accounted for 86% of the total pore volume. Through aluminum nuclear magnetic resonance measurement, see Figure 1, the ratio of the framework aluminum content at the intersection of the straight channel and the sinusoidal channel to the framework aluminum content in the straight channel and the sinusoidal channel is 2:1. The SiO2 / Al2O3 molar ratio of this catalyst is 282. Figure 2 XRD pattern of the catalyst obtained in Example 1, indicating that this catalyst is a ZSM-5 molecular sieve catalyst and the binder content is less than 0.2%.

[0072] Using a fixed-bed catalytic reaction device, with the raffinate mixed C4 from an ethylene plant (by mass, 40% butane and 60% butene) as the raw material, the prepared catalyst was evaluated for the reaction activity of olefin catalytic cracking to produce propylene and ethylene. The process conditions investigated were: 5 g of the catalyst was loaded, the reaction temperature was 500 °C, the reaction pressure was 0.02 MPa, and the weight hourly space velocity was 20 h -1 . The reaction results were as follows: the conversion rate of C4 olefins was 75%, the hydrogen transfer index was 6.5, and the selectivity for propylene and ethylene was 80.8%. The catalyst was reacted for 80 h, and the activity and selectivity of the catalyst did not change significantly, showing good stability.

[0073]

Example 2

[0074] (1) Preparation of ZSM-5 molecular sieve precursor powder

[0075] Using tetrapropylammonium hydroxide as the first template agent, aluminum nitrate as the first aluminum source, tetraethyl orthosilicate as the silicon source, and sodium hydroxide as the first base source, the molar ratio of tetrapropylammonium hydroxide in terms of NH4 + calculated, aluminum nitrate in terms of Al2O3, tetraethyl orthosilicate in terms of SiO2, sodium hydroxide in terms of OH - calculated, and water in terms of H2O was: NH4 + :Al2O3:SiO2:OH - :H2O = 0.2:0.0005:1:0.4:20. After thorough mixing and stirring, it was transferred to an autoclave, crystallized at 80 °C for 10 h, and then cooled for standby. According to the total amount of the silicon source and the first and second aluminum sources, sodium aluminate, the second aluminum source after removing the first aluminum source, was added in a ratio of SiO2 / Al2O3 molar ratio of 1000. The second template agent pyridine was added in a ratio of NH4 + / Al2O3 molar ratio of 300:1 with the second aluminum source, and was thoroughly mixed with the above crystallization solution. The pH was adjusted to 8 with the second base source sodium hydroxide, and then transferred to a stainless steel autoclave for secondary hydrothermal crystallization at 200 °C for 10 h. The synthesized product was washed with water, dried at 80 °C for 20 h, and calcined at 500 °C for 15 h to obtain the ZSM-5 molecular sieve precursor powder.

[0076] (2) Preparation of the catalyst precursor

[0077] 100 g of the above-mentioned ZSM-5 molecular sieve raw powder, 80 g of silica white, and 0.68 g of aluminum sol (with a mass fraction of Al2O3 of 20%) were kneaded with 50 g of water, extruded into strips, and dried at 120 °C for 5 h to obtain a catalyst precursor;

[0078] (3) Preparation of hydrogen-type ZSM-5 molecular sieve

[0079] Using hexamethylenediamine as the third template agent, a mixture of 60 g of hexamethylenediamine and 30 g of distilled water was pre-added to the reaction kettle. 20 g of the above-prepared strip-shaped catalyst precursor was placed above the porous stainless steel mesh in the reaction kettle, sealed, and crystallized at 150 °C for 80 h. After the product was taken out, it was washed with distilled water, dried at 100 °C for 10 h, and calcined in an air atmosphere at 600 °C for 5 h.

[0080] Then, it was subjected to ammonium exchange three times in a 10% ammonium nitrate solution at 80 °C, dried, and calcined in a muffle furnace at 550 °C for 4 h to obtain hydrogen-type ZSM-5 molecular sieve.

[0081] (4) Impregnation of metal components

[0082] The obtained hydrogen-type ZSM-5 molecular sieve solid was placed in a neodymium nitrate solution with a Nd mass content of 2% of 20 g for impregnation for 5 h, dried at 60 °C for 20 h, and calcined at 600 °C for 8 h.

[0083] Finally, the above solid was placed in a calcium nitrate solution with a Ca weight content of 0.8% of 20 g for impregnation for 10 h, dried at 100 °C, and calcined at 500 °C for 10 h to obtain the catalyst. The XRD pattern of the obtained catalyst is similar to Figure 2 that, indicating that this catalyst is a ZSM-5 molecular sieve catalyst and the binder content is less than 0.2%.

[0084] Through physical adsorption testing, the total pore volume of the catalyst is 0.4 mL / g, and the micropore pore volume accounts for 90% of the total pore volume. Through aluminum nuclear magnetic measurement, the ratio of the amount of framework aluminum at the intersection of the straight pore channels and the sinusoidal pore channels to the amount of framework aluminum in the straight pore channels and the sinusoidal pore channels is 1.5:1. The SiO2 / Al2O3 molar ratio of this catalyst is 925.

[0085] The catalyst evaluation method is the same as that in Example 1, and the reaction results are as follows: the conversion rate of C4 olefins is 73%, the hydrogen transfer index is 4.8, and the selectivity of propylene and ethylene is 85.6%. The catalyst reacts for 78 h, and the activity and selectivity of the catalyst do not change significantly, showing good stability.

[0086]

Example 3

[0087] (1) Preparation of ZSM-5 molecular sieve raw powder

[0088] Using tetrapropylammonium bromide as the first template agent, aluminum nitrate as the first aluminum source, silica sol as the silicon source, sodium hydroxide as the first base source, the molar ratio of tetrapropylammonium bromide calculated as NH4 + calculated as Al2O3 for aluminum nitrate, SiO2 for silica sol, OH - calculated as water for sodium hydroxide, and H2O for water is: NH4 + :Al2O3:SiO2:OH - :H2O = 0.3:0.001:1:0.2:15. After thorough mixing and stirring, it is transferred into an autoclave, crystallized at 100 °C for 8 h, and then cooled for standby. According to the total amount of the silicon source and the first and second aluminum sources, potassium alum dodecahydrate as the second aluminum source after removing the first aluminum source is added at a ratio of SiO2 / Al2O3 molar ratio of 300. The second template agent and the second aluminum source are added with n-butylamine as the second template agent at a ratio of NH4 + / Al2O3 molar ratio of 200:1. It is thoroughly mixed with the above crystallization solution, and the pH is adjusted to 10 with sodium hydroxide as the second base source, and then transferred into a stainless steel autoclave for secondary hydrothermal crystallization at 120 °C for 100 h. The synthesized product is washed with water, dried at 90 °C for 15 h, and calcined at 600 °C for 10 h to obtain the ZSM-5 molecular sieve precursor powder.

[0089] (2) Preparation of catalyst precursor

[0090] 100 g of the above ZSM-5 molecular sieve precursor powder, 25 g of silica sol containing 40 wt% SiO2, and 0.056 g of alumina are kneaded, extruded into pellets, and dried at 80 °C for 10 h to obtain the catalyst precursor;

[0091] (3) Preparation of hydrogen-form ZSM-5 molecular sieve

[0092] Using ethylamine as the third template agent, a mixture of 30 g of ethylamine and 30 g of distilled water is pre-added to the reaction kettle. 20 g of the above-prepared strip-shaped catalyst precursor is placed above the porous stainless steel mesh in the reaction kettle, sealed, and subjected to gas-solid phase hydrothermal crystallization at 130 °C for 100 h. After the product is taken out, it is washed with distilled water, dried at 90 °C for 15 h, and then calcined in an air atmosphere at 550 °C for 10 h.

[0093] Then, it is subjected to ammonium exchange 3 times in a 5 wt% ammonium nitrate solution at 90 °C, dried, and calcined in a muffle furnace at 500 °C for 4 h to obtain the catalyst. The XRD pattern of the obtained catalyst is Figure 2 similar, indicating that this catalyst is a ZSM-5 molecular sieve catalyst and the binder content is less than 0.2%.

[0094] After physical adsorption testing, the total pore volume of the catalyst is 0.5 mL / g, of which the micropore volume accounts for 87% of the total pore volume. As determined by aluminum NMR, the ratio of the amount of framework aluminum at the intersection of the straight channels and the sinusoidal channels to the amount of framework aluminum in the straight channels and the sinusoidal channels is 2:1. The SiO2 / Al2O3 molar ratio of this catalyst is 280.

[0095] The catalyst evaluation method is the same as in Example 1, and the reaction results are as follows: the conversion rate of C4 olefins is 76%, the hydrogen transfer index is 9.6, and the selectivity of propylene and ethylene is 68.2%. The catalyst reacts for 82 h, and the activity and selectivity of the catalyst do not change significantly, showing good stability.

[0096]

Example 4

[0097] (1) Preparation of ZSM-5 molecular sieve raw powder

[0098] Using tetrapropylammonium bromide as the first template agent, aluminum nitrate as the first aluminum source, silica sol as the silicon source, and sodium hydroxide as the first base source, the molar ratio of tetrapropylammonium bromide in terms of NH4 + calculated, aluminum nitrate in terms of Al2O3, silica sol in terms of SiO2, sodium hydroxide in terms of OH - calculated, and water in terms of H2O is: NH4 + :Al2O3:SiO2:OH - :H2O = 0.3:0.001:1:0.2:15. After thorough mixing and stirring, it is transferred to an autoclave, crystallized at 100 °C for 8 h, and then cooled for standby. According to the total amount of the silicon source and the first and second aluminum sources, potassium alum dodecahydrate, the second aluminum source after removing the first aluminum source, is added in a ratio of SiO2 / Al2O3 molar ratio of 300. The second template agent, n-butylamine, is added in a ratio of NH4 + / Al2O3 molar ratio of 200:1 to the second aluminum source, and is thoroughly mixed with the above crystallization solution. The pH is adjusted to 10 with the second base source, sodium hydroxide, and then transferred to a stainless steel autoclave for secondary hydrothermal crystallization at 120 °C for 100 h. The synthesized product is washed with water, dried at 90 °C for 15 h, and calcined at 600 °C for 10 h to obtain the ZSM-5 molecular sieve raw powder.

[0099] (2) Preparation of catalyst precursor

[0100] 100 g of the above ZSM-5 molecular sieve raw powder, 25 g of silica sol containing 40 wt% SiO2, and 0.056 g of alumina are kneaded, extruded into pellets, and dried at 80 °C for 10 h to obtain the catalyst precursor;

[0101] (3) Preparation of hydrogen-form ZSM-5 molecular sieve

[0102] Using ethylamine as the third template agent, a mixture of 30 g of ethylamine and 30 g of distilled water was pre-added to the autoclave. 20 g of the above-prepared strip-shaped catalyst precursor was placed above the porous stainless steel mesh in the autoclave, sealed, and subjected to gas-solid hydrothermal crystallization at 130 °C for 100 h. After the product was taken out, it was washed with distilled water, dried at 90 °C for 15 h, and then calcined in air atmosphere at 550 °C for 10 h.

[0103] It was then subjected to ammonium exchange three times in a 5 wt% ammonium nitrate solution at 90 °C, dried, and calcined in a muffle furnace at 500 °C for 4 h to obtain a hydrogen-form ZSM-5 molecular sieve.

[0104] (4) Impregnating metal components

[0105] The obtained hydrogen-form ZSM-5 molecular sieve solid was placed in a 20 g praseodymium nitrate solution with a Pr weight content of 1% for impregnation for 10 h, dried at 100 °C for 10 h, and calcined at 550 °C for 8 h. The catalyst was thus obtained. The XRD pattern of the obtained catalyst was similar to Figure 2 that, indicating that this catalyst was a ZSM-5 molecular sieve catalyst and the binder content was less than 0.2%.

[0106] Through physical adsorption tests, the total pore volume of the catalyst was 0.4 mL / g, and the micropore pore volume accounted for 86% of the total pore volume. Through aluminum NMR determination, the ratio of the amount of framework aluminum at the intersection of the straight pore channels and the sinusoidal pore channels to the amount of framework aluminum in the straight pore channels and the sinusoidal pore channels was 2:1. The SiO2 / Al2O3 molar ratio of this catalyst was 285.

[0107] The catalyst evaluation method was the same as that in Example 1, and the reaction results were as follows: the conversion rate of C4 olefins was 77.3%, the hydrogen transfer index was 8.8, and the selectivity of propylene and ethylene was 70.2%. The catalyst reacted for 76 h, and the activity and selectivity of the catalyst did not change significantly, showing good stability.

[0108]

Example 5

[0109] (1) Preparation of ZSM-5 molecular sieve raw powder

[0110] Using tetrapropylammonium bromide as the first template agent, aluminum nitrate as the first aluminum source, silica sol as the silicon source, and sodium hydroxide as the first base source, the molar ratio of tetrapropylammonium bromide based on NH4 + calculated, aluminum nitrate based on Al2O3, silica sol based on SiO2, sodium hydroxide based on OH - calculated, and water based on H2O was: NH4 + :Al2O3:SiO2:OH -: H2O = 0.3:0.001:1:0.2:15. After thorough mixing and stirring, it is transferred into an autoclave, crystallized at 100 °C for 8 h, and then cooled for standby. According to the total amount of the silicon source, the first aluminum source, and the second aluminum source, potassium alum dodecahydrate, the second aluminum source after removing the first aluminum source, is added at a ratio of SiO2 / Al2O3 molar ratio of 300. The second template agent and the second aluminum source are added with n-butylamine, the second template agent, at a ratio of NH4 + / Al2O3 molar ratio of 200:1. It is thoroughly mixed with the above crystallization solution, and the pH is adjusted to 10 with sodium hydroxide, the second base source. Then it is transferred into a stainless-steel autoclave for secondary hydrothermal crystallization at 120 °C for 100 h. The synthesized product is washed with water, dried at 90 °C for 15 h, and calcined at 600 °C for 10 h to obtain the ZSM-5 molecular sieve raw powder.

[0111] (2) Preparation of catalyst precursor

[0112] 100 g of the above ZSM-5 molecular sieve raw powder, 25 g of silica sol containing 40 wt% SiO2, and 0.056 g of alumina are kneaded, extruded into strips, and dried at 80 °C for 10 h to obtain the catalyst precursor.

[0113] (3) Preparation of hydrogen-form ZSM-5 molecular sieve

[0114] Using ethylamine as the third template agent, a mixture of 30 g of ethylamine and 30 g of distilled water is pre-added into the reaction kettle. 20 g of the above-prepared strip-shaped catalyst precursor is placed above the porous stainless-steel mesh in the reaction kettle, sealed, and subjected to gas-solid phase hydrothermal crystallization at 130 °C for 100 h. After the product is taken out, it is washed with distilled water, dried at 90 °C for 15 h, and then calcined in an air atmosphere at 550 °C for 10 h.

[0115] It is then subjected to ammonium exchange 3 times in a 5 wt% ammonium nitrate solution at 90 °C, dried, and calcined in a muffle furnace at 500 °C for 4 h to obtain the hydrogen-form ZSM-5 molecular sieve.

[0116] (4) Impregnation of metal components

[0117] The obtained hydrogen-form ZSM-5 molecular sieve solid is placed in 20 g of a magnesium nitrate solution with a Mg mass content of 2% for impregnation for 8 h, dried at 100 °C for 10 h, and calcined at 550 °C for 8 h to obtain the catalyst. The XRD pattern of the obtained catalyst is similar to Figure 2 that, indicating that this catalyst is a ZSM-5 molecular sieve catalyst and the binder content is less than 0.2%.

[0118] According to the physical adsorption test, the total pore volume of the catalyst is 0.6mL / g, of which the micropore volume accounts for 83% of the total pore volume. According to the aluminum nuclear magnetic resonance measurement, the ratio of the amount of skeleton aluminum located at the intersection of the straight pores and the sinusoidal pores to the amount of skeleton aluminum in the straight pores and the sinusoidal pores is 1.8:1. The SiO2 / Al2O3 molar ratio of the catalyst is 282.

[0119] The catalyst evaluation method was the same as in Example 1, and the reaction results were: C4 olefin conversion rate 75.8%, hydrogen transfer index 9.3, propylene ethylene selectivity 69.5%. The catalyst was reacted for 75 hours, and the catalyst activity and selectivity did not change significantly, showing good stability.

[0120] [Example 6]

[0121] (1) Preparation of ZSM-5 molecular sieve raw powder

[0122] Tetrapropylammonium bromide is used as the first template, aluminum sulfate is used as the first aluminum source, silica sol is used as the silicon source, sodium hydroxide is used as the first alkali source, and tetrapropylammonium bromide is used as NH4 + Aluminum sulfate is calculated as Al2O3, silica sol is calculated as SiO2, and sodium hydroxide is calculated as OH - The molar ratio of NH4 + :Al2O3:SiO2:OH - :H2O=0.2:0.005:1:0.4:20, transfer to autoclave after fully mixing and stirring, crystallize at 150℃ for 2h and then cool for use. According to the total amount of silicon source, the first aluminum source and the second aluminum source, according to the molar ratio of SiO2 / Al2O3 of 100, add the second aluminum source potassium aluminum sulfate after removing the first aluminum source, and the second template agent and the second aluminum source are mixed with NH4 + The second template agent n-butylamine was added at a ratio of 500:1 to Al2O3 molar ratio, and the mixture was fully mixed with the above crystallization solution. The pH was adjusted to 10 with the second alkali source sodium hydroxide, and then the mixture was transferred to a stainless steel autoclave for the second hydrothermal crystallization at 150°C for 40h. The synthesized product was washed with water, dried at 90°C for 15h, and calcined at 600°C for 10h to obtain ZSM-5 molecular sieve raw powder.

[0123] (2) Preparation of catalyst precursor

[0124] Add 40 g of water to 115 g of the above-mentioned ZSM-5 molecular sieve raw powder, 10 g of white carbon black and 0.85 g of aluminum sol (containing 20% by mass of Al2O3), mix and knead, extrude into strips, and dry at 120°C for 5 hours to obtain a catalyst precursor.

[0125] (3) Preparation of hydrogenated ZSM-5 molecular sieve

[0126] Using hexamethylenediamine as the third template agent, a mixture of 60 g of hexamethylenediamine and 30 g of distilled water was pre-added to the reaction kettle. 30 g of the above-prepared strip-shaped catalyst precursor was placed above the porous stainless steel mesh in the reaction kettle, sealed, and crystallized at 200 °C for 20 h. After the product was taken out, it was washed with distilled water, dried at 100 °C for 10 h, air-dried, and then calcined in an air atmosphere at 450 °C for 10 h.

[0127] Then, it was subjected to ammonium exchange 6 times in a 5% ammonium sulfate solution at 90 °C, dried, and calcined in a muffle furnace at 600 °C for 4 h to obtain a hydrogen-type ZSM-5 molecular sieve.

[0128] (4) Impregnating metal components

[0129] The obtained hydrogen-type ZSM-5 molecular sieve solid was placed in a neodymium nitrate solution with a Ce mass content of 0.2% and a mass of 20 g for impregnation for 3 h, dried at 100 °C for 10 h, and calcined at 450 °C for 10 h.

[0130] Finally, the above solid was placed in a magnesium nitrate solution with a Mg weight content of 0.2% and a mass of 20 g for impregnation for 10 h, dried at 100 °C, and calcined at 500 °C for 10 h to obtain the catalyst. The XRD pattern of the obtained catalyst is similar to Figure 2 that shown, indicating that this catalyst is a ZSM-5 molecular sieve catalyst and the binder content is less than 0.2%.

[0131] Through physical adsorption testing, the total pore volume of the catalyst is 0.8 mL / g, and the micropore pore volume accounts for 90% of the total pore volume. Through aluminum nuclear magnetic resonance determination, the ratio of the amount of framework aluminum at the intersection of the straight pore channels and the sinusoidal pore channels to the amount of framework aluminum in the straight pore channels and the sinusoidal pore channels is 3:1. The SiO2 / Al2O3 molar ratio of this catalyst is 98.

[0132] The catalyst evaluation method is the same as that in Example 1, and the reaction results are as follows: the conversion rate of C4 olefins is 76.3%, the hydrogen transfer index is 5.3, and the selectivity of propylene and ethylene is 84.5%. The catalyst reacts for 77 h, and the activity and selectivity of the catalyst do not change significantly, showing good stability.

[0133]

Example 7

[0134] (1) Preparation of ZSM-5 molecular sieve raw powder

[0135] Using tetraethylammonium chloride as the first template agent, aluminum phosphate as the first aluminum source, water glass as the silicon source, and sodium hydroxide as the first base source, the molar ratio of tetraethylammonium chloride calculated as NH4 + 、aluminum phosphate calculated as Al2O3、water glass calculated as SiO2、sodium hydroxide calculated as OH - 、and water calculated as H2O is: NH4 + :Al2O3:SiO2:OH -:H2O = 0.2:0.001:1:0.4:20. After sufficient mixing and stirring, it is transferred into an autoclave, crystallized at 80 °C for 10 h, and then cooled for standby. According to the total amount of the silicon source, the first aluminum source and the second aluminum source, and in the ratio of the molar ratio of SiO2 / Al2O3 being 100, sodium aluminate, the second aluminum source after removing the first aluminum source, is added. The second template agent and the second aluminum source are added in the ratio of the molar ratio of NH4 + / Al2O3 being 200:1. The second template agent, hexamethylenediamine, is added and mixed thoroughly with the above crystallization solution. The pH is adjusted to 10 with the second base source, sodium hydroxide, and then transferred into a stainless-steel autoclave for secondary hydrothermal crystallization at 120 °C for 100 h. The synthesized product is washed with water, dried at 100 °C for 10 h, and calcined at 650 °C for 8 h to obtain the ZSM-5 molecular sieve precursor powder.

[0136] (2) Preparation of catalyst precursor

[0137] 112 g of the above ZSM-5 molecular sieve precursor powder, 40 g of white carbon black, and 3.4 g of aluminum sol (with the mass fraction of Al2O3 being 20%) are mixed with 60 g of water by kneading, extruded into strips, and dried at 80 °C for 10 h to obtain the catalyst precursor.

[0138] (3) Preparation of hydrogen-type ZSM-5 molecular sieve

[0139] Using triethylamine as the third template agent, a mixture of 50 g of triethylamine and 50 g of distilled water is pre-added into the reaction kettle. 50 g of the above-prepared strip-shaped catalyst precursor is placed above the porous stainless-steel mesh in the reaction kettle, sealed, and crystallized at 130 °C for 100 h. After the product is taken out, it is washed with distilled water, dried at 80 °C for 20 h, and calcined in an air atmosphere at 500 °C for 8 h.

[0140] Then, it is subjected to ammonium exchange 4 times in a 10% ammonium chloride solution at 80 °C, dried, and calcined in a muffle furnace at 500 °C for 8 h to obtain the hydrogen-type ZSM-5 molecular sieve.

[0141] (4) Impregnation of metal components

[0142] The obtained hydrogen-type ZSM-5 molecular sieve solid is placed in a 20 g lanthanum nitrate solution with a La mass content of 5% for impregnation for 10 h, dried at 100 °C for 12 h, and calcined at 500 °C for 10 h.

[0143] Finally, the above solid is placed in a 20 g barium nitrate solution with a Ba mass content of 0.5% for impregnation for 10 h, dried at 100 °C, and calcined at 500 °C for 10 h to obtain the catalyst. The XRD pattern of the obtained catalyst is similar to Figure 2 that, indicating that this catalyst is a ZSM-5 molecular sieve catalyst and the binder content is less than 0.2%.

[0144] According to the physical adsorption test, the total pore volume of the catalyst is 0.1mL / g, of which the micropore volume accounts for 70% of the total pore volume. According to the aluminum nuclear magnetic resonance measurement, the ratio of the amount of skeleton aluminum located at the intersection of the straight pores and the sinusoidal pores to the amount of skeleton aluminum in the straight pores and the sinusoidal pores is 2:1. The SiO2 / Al2O3 molar ratio of the catalyst is 96.

[0145] The catalyst evaluation method was the same as in Example 1, and the reaction results were: C4 olefin conversion rate 71%, hydrogen transfer index 5.6, propylene ethylene selectivity 80.3%. The catalyst was reacted for 78 hours, and the catalyst activity and selectivity did not change significantly, showing good stability.

[0146] [Example 8]

[0147] (1) Preparation of ZSM-5 molecular sieve raw powder

[0148] Ammonia water is used as the first template, aluminum nitrate is used as the first aluminum source, tetraethyl orthosilicate is used as the silicon source, sodium hydroxide is used as the first alkali source, and ammonia water is NH4 + Aluminum nitrate is calculated as Al2O3, ethyl orthosilicate is calculated as SiO2, and sodium hydroxide is calculated as OH - The molar ratio of NH4 + :Al2O3:SiO2:OH - :H2O=0.3:0.008:1:0.2:20, transfer to autoclave after fully mixing and stirring, crystallize at 80℃ for 10h and then cool for use. According to the total amount of silicon source, the first aluminum source and the second aluminum source, according to the molar ratio of SiO2 / Al2O3 of 500, add the second aluminum source potassium aluminum sulfate after removing the first aluminum source, and the second template agent and the second aluminum source are mixed with NH4 + The second template pyridine was added in a ratio of 400:1 to the molar ratio of Al2O3 / Al2O3, and the mixture was fully mixed with the above crystallization solution. The pH was adjusted to 8 with the second alkali source sodium hydroxide, and then the mixture was transferred to a stainless steel autoclave for the second hydrothermal crystallization at 180°C for 20h. The synthesized product was washed with water, dried at 90°C for 15h, and calcined at 600°C for 10h to obtain the ZSM-5 molecular sieve raw powder.

[0149] (2) Preparation of catalyst precursor

[0150] 150 g of the above-mentioned ZSM-5 molecular sieve powder, 100 g of white carbon black and 1.7 g of aluminum sol (containing 20% by mass of Al2O3) were added with 50 g of water and kneaded, extruded into strips, and dried at 120°C for 5 h to obtain a catalyst precursor;

[0151] (3) Preparation of hydrogenated ZSM-5 molecular sieve

[0152] Using hexamethylenediamine as the third template agent, a mixture of 50 g of hexamethylenediamine and 30 g of distilled water was pre-added to the reaction kettle. 20 g of the above-prepared strip-shaped catalyst precursor was placed above the porous stainless steel mesh in the reaction kettle, sealed, and crystallized at 150 °C for 80 h. After the product was taken out, it was washed with distilled water, dried at 100 °C for 10 h, air-dried, and then calcined in an air atmosphere at 600 °C for 5 h.

[0153] It was then subjected to ammonium exchange three times in a 10% ammonium nitrate solution at 80 °C, dried, and calcined in a muffle furnace at 550 °C for 4 h to obtain a hydrogen-form ZSM-5 molecular sieve.

[0154] (4) Impregnating with metal components

[0155] The obtained hydrogen-form ZSM-5 molecular sieve solid was placed in a praseodymium nitrate solution with a Pr mass content of 1% and a weight of 20 g for impregnation for 5 h, dried at 60 °C for 20 h, and calcined at 600 °C for 8 h.

[0156] Finally, the above solid was placed in a strontium nitrate solution with an Sr weight content of 0.3% and a weight of 20 g for impregnation for 10 h, dried at 100 °C, and calcined at 500 °C for 10 h to obtain the catalyst. The XRD pattern of the obtained catalyst is the same as Figure 2 that of [reference], indicating that this catalyst is a ZSM-5 molecular sieve catalyst and the binder content is less than 0.2%.

[0157] Through physical adsorption tests, the total pore volume of the catalyst is 0.6 mL / g, and the micropore pore volume accounts for 83% of the total pore volume. Through aluminum nuclear magnetic measurement, the ratio of the amount of framework aluminum at the intersection of the straight pore channels and the sinusoidal pore channels to the amount of framework aluminum in the straight pore channels and the sinusoidal pore channels is 1.8:1. The SiO2 / Al2O3 molar ratio of this catalyst is 488.

[0158] The catalyst evaluation method is the same as that in Example 1, and the reaction results are as follows: the conversion rate of C4 olefins is 76.5%, the hydrogen transfer index is 5.1, and the selectivity of propylene and ethylene is 83.9%. The catalyst reacts for 80 h, and the activity and selectivity of the catalyst do not change significantly, showing good stability.

[0159]

Example 9

[0160] Using the catalyst of Example 8, the prepared catalyst was evaluated for its reaction activity in the catalytic cracking of olefins to produce propylene and ethylene using nitrogen-diluted pentene (the volume ratio of nitrogen to pentene is 1:1) as the raw material. The process conditions investigated were: 5 g of the catalyst was loaded, the reaction temperature was 580 °C, the reaction pressure was 0.3 MPa, and the weight hourly space velocity was 40 h -1 . The reaction results were as follows: the conversion rate of C5 olefins was 80%, the hydrogen transfer index was 5.3, and the selectivity of propylene and ethylene was 82.8%. The catalyst reacted for 78 h, and the activity and selectivity of the catalyst did not change significantly, showing good stability.

[0161] [Example 10]

[0162] The catalyst of Example 8 was used to evaluate the catalytic cracking of olefins to produce propylene and ethylene using hexene diluted with nitrogen (nitrogen and hexene volume ratio 1:1) as raw material. The process conditions used for the investigation were: 5 g catalyst, reaction temperature of 420°C, reaction pressure of 0.01 MPa, weight space velocity of 2 h -1 The reaction results were: C6 olefin conversion rate of 72%, hydrogen transfer index of 6.8, and selectivity of propylene and ethylene of 80.3%. The catalyst was reacted for 76 hours, and the activity and selectivity of the catalyst did not change significantly, showing good stability.

[0163] [Comparative Example 1]

[0164] (1) Preparation of ZSM-5 molecular sieve raw powder

[0165] Tetrapropylammonium bromide was used as template, aluminum nitrate was used as aluminum source, silica sol was used as silicon source, sodium hydroxide was used as alkali source, and tetrapropylammonium bromide was used as NH4 + Aluminum nitrate is calculated as Al2O3, silica sol is calculated as SiO2, and sodium hydroxide is calculated as OH - The molar ratio of NH4 + :Al2O3:SiO2:OH - :H2O=0.3:0.001:1:0.2:15, transfer to autoclave after thorough mixing and stirring, and crystallize at 100℃ for 8h. Wash the synthesized product with water, dry at 90℃ for 15h, and calcine at 600℃ for 10h to obtain ZSM-5 molecular sieve raw powder.

[0166] (2) Preparation of catalyst precursor

[0167] 100 g of the above ZSM-5 molecular sieve powder, 25 g of silica sol containing 40 wt% SiO2 and 0.056 g of alumina were mixed, extruded and dried at 80°C for 10 h to obtain a catalyst precursor;

[0168] (3) Preparation of hydrogenated ZSM-5 molecular sieve

[0169] Using ethylamine as the third template, a mixture of 30 grams of ethylamine and 30 grams of distilled water was pre-added in the reactor, and 20 grams of the strip catalyst precursor prepared above was placed on the porous stainless steel mesh in the reactor, sealed, and then subjected to gas-solid phase hydrothermal crystallization at 130°C for 100 hours. The product was taken out and washed with distilled water, dried at 90°C for 15 hours, and then calcined at 550°C in an air atmosphere for 10 hours.

[0170] The mixture was then ammonium exchanged three times in a 5 wt % ammonium nitrate solution at 90° C., dried, and calcined in a muffle furnace at 500° C. for 4 h to obtain a hydrogen-type ZSM-5 molecular sieve.

[0171] (4) Impregnation of metal components

[0172] The obtained hydrogen-type ZSM-5 molecular sieve solid was placed in 20 g of praseodymium nitrate solution with a Pr mass content of 1% for immersion for 10 hours, dried at 100° C. for 10 hours, and calcined at 550° C. for 8 hours.

[0173] Finally, the solid was placed in 20 g of magnesium nitrate solution with a 2% Mg weight content and immersed for 8 h, dried at 100° C. for 10 h, and calcined at 550° C. for 8 h to obtain a catalyst.

[0174] According to the physical adsorption test, the total pore volume of the catalyst is 0.6mL / g, of which the micropore volume accounts for 68% of the total pore volume. According to the aluminum nuclear magnetic resonance measurement, the ratio of the skeleton aluminum content at the intersection of the straight pore and the sinusoidal pore to the skeleton aluminum content in the straight pore and the sinusoidal pore is 1:1. XRD is similar to Figure 2 , the binder content in this catalyst is less than 0.2%.

[0175] The catalyst evaluation method was the same as in Example 1. The reaction results were: C4 olefin conversion rate 76%, hydrogen transfer index 9.2, propylene ethylene selectivity 69.3%. After 65 hours of catalyst reaction, the catalyst activity and selectivity began to decline.

[0176] [Comparative Example 2]

[0177] (1) Preparation of ZSM-5 molecular sieve raw powder

[0178] Tetrapropylammonium bromide is used as the first template, aluminum nitrate is used as the first aluminum source, silica sol is used as the silicon source, sodium hydroxide is used as the first alkali source, and tetrapropylammonium bromide is used as NH4 + Aluminum nitrate is calculated as Al2O3, silica sol is calculated as SiO2, and sodium hydroxide is calculated as OH - The molar ratio of NH4 + :Al2O3:SiO2:OH - :H2O=0.3:0.001:1:0.2:15, mix thoroughly and transfer to autoclave, crystallize at 100℃ for 8h and then cool for use. According to the total amount of silicon source, the first aluminum source and the second aluminum source, according to the molar ratio of SiO2 / Al2O3 of 300, add the second aluminum source aluminum nitrate after removing the first aluminum source, and the second template agent and the aluminum source are mixed with NH4 +The second template agent, n-butylamine, was added in a ratio of 200:1 in terms of the molar ratio of / Al2O3, and was thoroughly mixed with the above crystallization solution. The pH was adjusted to 10 with the second alkali source, sodium hydroxide, and then transferred to a stainless-steel autoclave for secondary hydrothermal crystallization at 120 °C for 100 h. The synthesized product was washed with water, dried at 90 °C for 15 h, and calcined at 600 °C for 10 h to obtain the ZSM-5 molecular sieve raw powder.

[0179] (2) Preparation of catalyst precursor

[0180] 50 g of the above ZSM-5 molecular sieve raw powder, 25 g of silica sol containing 40 wt% SiO2, and 0.056 g of alumina were kneaded and extruded into strips, and dried at 80 °C for 10 h to obtain the catalyst precursor;

[0181] (3) Preparation of hydrogen-type ZSM-5 molecular sieve

[0182] Using ethylamine as the third template agent, a mixture of 30 g of ethylamine and 30 g of distilled water was pre-added to the reaction kettle. 20 g of the above-prepared strip-shaped catalyst precursor was placed above the porous stainless-steel mesh in the reaction kettle, sealed, and subjected to gas-solid phase hydrothermal crystallization at 130 °C for 100 h. After the product was taken out, it was washed with distilled water, dried at 90 °C for 15 h, and then calcined in an air atmosphere at 550 °C for 10 h.

[0183] Then, it was subjected to ammonium exchange 3 times in a 5 wt% ammonium nitrate solution at 90 °C, dried, and calcined in a muffle furnace at 500 °C for 4 h to obtain the hydrogen-type ZSM-5 molecular sieve.

[0184] (4) Impregnation of metal components

[0185] The obtained hydrogen-type ZSM-5 molecular sieve solid was placed in a 20 g praseodymium nitrate solution with a Pr weight content of 1% for impregnation for 10 h, dried at 100 °C for 10 h, and calcined at 550 °C for 8 h.

[0186] Finally, the above solid was placed in a 20 g magnesium nitrate solution with a Mg weight content of 2% for impregnation for 8 h, dried at 100 °C for 10 h, and calcined at 550 °C for 8 h to obtain the catalyst.

[0187] Through physical adsorption tests, the total pore volume of the catalyst was 0.8 mL / g, and the micropore pore volume accounted for 77% of the total pore volume. Through aluminum nuclear magnetic measurement, the ratio of the amount of framework aluminum at the intersection of the straight pore channels and the sinusoidal pore channels to the amount of framework aluminum in the straight pore channels and the sinusoidal pore channels was 0.8:1. The SiO2 / Al2O3 molar ratio of this catalyst was 280. XRD was similar to Figure 2 , and the binder content in this catalyst was less than 0.2%.

[0188] The catalyst evaluation method was the same as that in Example 1, and the reaction results were as follows: the conversion rate of C4 olefins was 72%, the hydrogen transfer index was 7.3, the selectivity of propylene and ethylene was 75.5%, the catalyst reacted for 70 h, and the activity and selectivity of the catalyst began to decline.

[0189] [Comparative Example 3]

[0190] (1) Preparation of ZSM-5 molecular sieve raw powder

[0191] Using tetrapropylammonium bromide as the first template agent, aluminum nitrate as the first aluminum source, silica sol as the silicon source, sodium hydroxide as the first base source, tetrapropylammonium bromide in terms of NH4 + calculated, aluminum nitrate in terms of Al2O3, silica sol in terms of SiO2, sodium hydroxide in terms of OH - calculated, and water in terms of H2O, the molar ratio was: NH4 + :Al2O3:SiO2:OH - :H2O = 0.3:0.001:1:0.2:15. After thorough mixing and stirring, it was transferred to an autoclave, crystallized at 100 °C for 8 h, and then cooled for standby. According to the total amount of the silicon source and the first and second aluminum sources, potassium alum dodecahydrate, the second aluminum source after removing the first aluminum source, was added in a ratio of SiO2 / Al2O3 molar ratio of 300. The template agent tetrapropylammonium bromide was added in a ratio of NH4 + / Al2O3 molar ratio of 200:1 to the second aluminum source, and thoroughly mixed with the above crystallization solution. The pH was adjusted to 10 with the second base source sodium hydroxide, and then transferred to a stainless steel autoclave for secondary hydrothermal crystallization at 120 °C for 100 h. The synthesized product was washed with water, dried at 90 °C for 15 h, and calcined at 600 °C for 10 h to obtain the ZSM-5 molecular sieve raw powder.

[0192] (2) Preparation of catalyst precursor

[0193] 100 g of the above ZSM-5 molecular sieve raw powder, 25 g of silica sol containing 40 wt% SiO2, and 0.056 g of alumina were kneaded, extruded into pellets, and dried at 80 °C for 10 h to obtain the catalyst precursor;

[0194] (3) Preparation of hydrogen-type ZSM-5 molecular sieve

[0195] Using ethylamine as the third template agent, a mixture of 30 g of ethylamine and 30 g of distilled water was pre-added to the reaction kettle. 20 g of the above-prepared strip-shaped catalyst precursor was placed above the porous stainless steel mesh in the reaction kettle, sealed, and subjected to gas-solid phase hydrothermal crystallization at 130 °C for 100 h. After the product was taken out, it was washed with distilled water, dried at 90 °C for 15 h, and then calcined in an air atmosphere at 550 °C for 10 h.

[0196] The mixture was then ammonium exchanged three times in a 5 wt % ammonium nitrate solution at 90° C., dried, and calcined in a muffle furnace at 500° C. for 4 h to obtain a hydrogen-type ZSM-5 molecular sieve.

[0197] (4) Impregnation of metal components

[0198] The obtained hydrogen-type ZSM-5 molecular sieve solid was placed in 20 g of praseodymium nitrate solution with a Pr weight content of 1% for immersion for 10 hours, dried at 100° C. for 10 hours, and calcined at 550° C. for 8 hours.

[0199] Finally, the solid was placed in 20 g of magnesium nitrate solution with a 2% Mg content for 8 h, dried at 100 ° C for 10 h, and calcined at 550 ° C for 8 h to obtain the catalyst. Figure 2 Similarly, this indicates that the catalyst is a ZSM-5 molecular sieve catalyst.

[0200] According to the physical adsorption test, the total pore volume of the catalyst is 0.28mL / g, of which the micropore volume accounts for 73% of the total pore volume. According to the aluminum nuclear magnetic resonance measurement, the ratio of the amount of skeleton aluminum at the intersection of the straight pore and the sinusoidal pore to the amount of skeleton aluminum in the straight pore and the sinusoidal pore is 1.2:1. The SiO2 / Al2O3 molar ratio of the catalyst is 285. XRD is similar to Figure 2 , the binder content in this catalyst is less than 0.2%.

[0201] The catalyst evaluation method was the same as in Example 1. The reaction results were: C4 olefin conversion rate was 69.8%, hydrogen transfer index was 7.2, selectivity for propylene and ethylene was 71.8%, and the catalyst activity and selectivity began to decrease after 72 hours of reaction.

[0202] [Comparative Example 4]

[0203] (1) Preparation of ZSM-5 molecular sieve raw powder

[0204] Tetrapropylammonium bromide is used as the first template, aluminum nitrate is used as the first aluminum source, silica sol is used as the silicon source, sodium hydroxide is used as the first alkali source, and tetrapropylammonium bromide is used as NH4 + Aluminum nitrate is calculated as Al2O3, silica sol is calculated as SiO2, and sodium hydroxide is calculated as OH - The molar ratio of NH4 + :Al2O3:SiO2:OH - :H2O=0.3:0.001:1:0.2:15, transfer to autoclave after fully mixing and stirring, crystallize at 100℃ for 8h and then cool for use. According to the total amount of silicon source, the first aluminum source and the second aluminum source, according to the molar ratio of SiO2 / Al2O3 of 300, add the second aluminum source potassium aluminum sulfate dodecahydrate after removing the first aluminum source, and the second template agent and the second aluminum source are mixed with NH4 +The second template agent n-butylamine was added in a ratio of 200:1 to / Al2O3, and fully mixed with the above crystallization solution. The pH was adjusted to 10 with the second alkali source sodium hydroxide, and then transferred to a stainless steel autoclave for secondary hydrothermal crystallization at 120 °C for 100 h. The synthesized product was washed with water, dried at 90 °C for 15 h, and calcined at 600 °C for 10 h to obtain the ZSM-5 molecular sieve raw powder.

[0205] (2) Preparation of catalyst precursor

[0206] 100 g of the above ZSM-5 molecular sieve raw powder, 25 g of silica sol containing 40 wt% SiO2, and 0.056 g of alumina were kneaded, extruded into strips, and dried at 80 °C for 10 h to obtain the catalyst precursor.

[0207] (3) Preparation of hydrogen-form ZSM-5 molecular sieve

[0208] 20 g of the above-prepared strip-shaped catalyst precursor was calcined at 550 °C for 10 h in an air atmosphere.

[0209] It was then subjected to ammonium exchange 3 times in a 5 wt% ammonium nitrate solution at 90 °C, dried, and calcined in a muffle furnace at 500 °C for 4 h to obtain the hydrogen-form ZSM-5 molecular sieve.

[0210] (4) Impregnation of metal components

[0211] The obtained hydrogen-form ZSM-5 molecular sieve solid was placed in 20 g of a praseodymium nitrate solution with a Pr mass content of 1% for impregnation for 10 h, dried at 100 °C for 10 h, and calcined at 550 °C for 8 h.

[0212] Finally, the above solid was placed in 20 g of a magnesium nitrate solution with a Mg weight content of 2% for impregnation for 8 h, dried at 100 °C for 10 h, and calcined at 550 °C for 8 h to obtain the catalyst. Figure 4 It is the XRD pattern of the catalyst obtained in Comparative Example 4, indicating that this catalyst is a ZSM-5 molecular sieve catalyst and the binder content is 10%.

[0213] Through physical adsorption testing, the total pore volume of the catalyst is 0.1 mL / g, and the micropore pore volume accounts for 68% of the total pore volume. Through aluminum nuclear magnetic resonance measurement, see Figure 3 , the ratio of the amount of framework aluminum at the intersection of the straight channels and the sinusoidal channels to the amount of framework aluminum in the straight channels and the sinusoidal channels is 0.8:1. The SiO2 / Al2O3 molar ratio of this catalyst is 282.

[0214] The catalyst evaluation method is the same as that in Example 1, and the reaction results are as follows: the conversion rate of C4 olefins is 65%, the hydrogen transfer index is 15.8, and the selectivity of propylene and ethylene is 58.5%.

[0215] From Figure 1 , Figure 3It can be seen that for the ZSM-5 molecular sieve catalyst of the present invention, the ratio of the amount of framework aluminum at the intersection of the straight channels and the sinusoidal channels to the amount of framework aluminum in the straight channels and in the sinusoidal channels is significantly higher than that of conventional catalysts.

[0216] From Figure 2 , Figure 4 It can be seen that the crystallinity of the catalyst obtained in Example 1 of the present invention is significantly higher than that of the catalyst obtained in Comparative Example 4, and the ZSM-5 molecular sieve catalyst obtained in Comparative Example 4 contains a large amount of binder components.

[0217] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A ZSM-5 molecular sieve catalyst, and the properties of the catalyst are as follows: the ratio of the amount of framework aluminum at the intersection of the straight channels and the sinusoidal channels to the amount of framework aluminum in the straight channels and the sinusoidal channels is 1.4:1 to 10:1, and the micropore volume accounts for 70% to 92% of the total pore volume; the total pore volume of the catalyst is 0.01 to 1.2 mL / g; In the ZSM-5 molecular sieve catalyst, based on the mass of the catalyst, the mass content of the binder is below 5%.

2. The catalyst according to claim 1, wherein In the catalyst, the ratio of the amount of framework aluminum at the intersection of the straight channels and the sinusoidal channels to the amount of framework aluminum in the straight channels and the sinusoidal channels is 1.4:1 to 4:

1.

3. The catalyst according to claim 1 or 2, characterized in that, The total pore volume of the catalyst is 0.1 to 0.8 mL / g.

4. The catalyst according to claim 1, wherein By weight, it comprises the following components: a) 90 to 100 parts of hydrogen-form ZSM-5 molecular sieve; b) 0 to 5 parts of rare earth elements; c) 0 to 5 parts of alkaline earth metal elements.

5. The catalyst according to claim 4, characterized in that, By weight, it comprises the following components: a) 92 to 99 parts of hydrogen-form ZSM-5 molecular sieve; b) 0.5 to 3.0 parts of rare earth elements; c) 0.5 to 5.0 parts of alkaline earth metal elements.

6. The catalyst according to claim 4, characterized in that, The silicon-aluminum molar ratio SiO2 / Al2O3 of the hydrogen-form ZSM-5 molecular sieve is 80 to 1500.

7. The catalyst according to claim 6, characterized in that, The silicon-aluminum molar ratio SiO2 / Al2O3 of the hydrogen-form ZSM-5 molecular sieve is 80 to 1000.

8. The catalyst according to claim 4, characterized in that, The rare earth elements are selected from at least one of La, Ce, Pr, and Nd; and / or, the alkaline earth metal elements are selected from at least one of Mg, Ca, Sr, and Ba.

9. The catalyst according to claim 1, characterized in that, In the ZSM-5 molecular sieve catalyst, based on the mass of the catalyst, the mass content of the binder is below 2%.

10. The catalyst according to claim 9, characterized in that, In the ZSM-5 molecular sieve catalyst, based on the mass of the catalyst, the mass content of the binder is below 0.5%.

11. A preparation method of the ZSM-5 molecular sieve catalyst according to any one of claims 1-10, comprising: (1) Preparing ZSM-5 molecular sieve raw powder; (2) Kneading and molding the molecular sieve raw powder obtained in step (1) with a binder, and drying to obtain a catalyst precursor; (3) Performing third hydrothermal crystallization and ammonium exchange on the catalyst precursor obtained in step (2) in the presence of a third template agent to obtain a ZSM-5 molecular sieve catalyst.

12. The preparation method according to claim 11, characterized in that, The preparation method further comprises step (4), specifically as follows: the hydrogen-form ZSM-5 molecular sieve obtained in step (3) is loaded with rare earth metals and / or alkaline earth metal elements to obtain a metal-containing ZSM-5 molecular sieve catalyst.

13. The preparation method according to claim 11 or 12, characterized in that, The preparation method of the ZSM-5 molecular sieve raw powder in step (1) comprises: (11) Mixing a first template agent, a first aluminum source, a silicon source, a first alkali source and water, and performing first hydrothermal crystallization; (12) Mixing a second aluminum source, a second template agent, a second alkali source and the mixture obtained after crystallization in step (11), and performing second hydrothermal crystallization to obtain ZSM-5 molecular sieve raw powder.

14. The preparation method according to claim 13, characterized in that, The first template agent in step (11) is at least one of tetrapropylammonium bromide, tetrapropylammonium hydroxide, tetraethylammonium chloride, and ammonia water; and / or, the first aluminum source in step (11) is at least one of aluminum nitrate, aluminum sulfate, or aluminum phosphate; And / or, the conditions of the first hydrothermal crystallization in step (11) are as follows: the crystallization temperature is 80 - 150 °C, and the crystallization time is 2 - 10 h; and / or, in step (11), the molar ratio of the first templating agent calculated as NH4 + , the first aluminum source calculated as Al2O3, the silicon source calculated as SiO2, the first base source calculated as OH - , and water calculated as H2O is: NH4 + : Al2O3: SiO2: OH - : H2O = 0.2 - 0.3: 0.0005 - 0.001: 1: 0.2 - 0.4: 15 - 20.

15. The preparation method according to claim 13, characterized in that, The second aluminum source in step (12) is at least one of potassium alum or sodium metaaluminate; And / or, the addition amount of the second aluminum source in step (12) calculated as Al2O3 accounts for more than 30% of the total mass of the second aluminum source in step (12) and the first aluminum source in step (11) calculated as Al2O3; And / or, the second template agent in step (12) is at least one of n-butylamine, hexamethylenediamine, and pyridine; And / or, in step (12), the pH value of the system is controlled to be 8 - 10 with a second base source; And / or, the conditions of the second hydrothermal crystallization are as follows: the crystallization temperature is 120 - 200 °C, and the crystallization time is 10 - 100 h.

16. The preparation method according to claim 15, characterized in that, The addition amount of the second aluminum source in step (12) calculated as Al2O3 accounts for more than 40% of the total mass of the second aluminum source in step (12) and the first aluminum source in step (11) calculated as Al2O3.

17. The preparation method according to claim 11 or 12, characterized in that, The third template agent in step (3) is at least one of ammonia water, ethylamine, ethylenediamine, triethylamine, n-butylamine, hexamethylenediamine, tetrapropylammonium bromide, or tetrapropylammonium hydroxide; And / or, the third hydrothermal crystallization is to carry out crystallization on the catalyst precursor obtained in step (2) in a vapor containing the third template agent, and the mass ratio of the third template agent to the catalyst precursor is 1 - 3:1, and the crystallization is carried out at 130 - 200 °C for 20 - 200 h.

18. Use of the catalyst according to any one of claims 1 - 10 or the catalyst prepared by the preparation method according to any one of claims 11 - 17 in the catalytic cracking of olefins to produce propylene and ethylene.

19. The application according to claim 18, wherein Using at least one of C4-C6 olefins as a raw material, the reaction conditions are as follows: the reaction temperature is 400-600 °C, the reaction pressure is 0-0.3 MPa, and the weight hourly space velocity is 1-50 h -1 .

20. The application according to claim 19, wherein The reaction conditions are as follows: the reaction temperature is 420 - 580 °C, the reaction pressure is 0.01 - 0.2 MPa, and the weight hourly space velocity is 2 - 40 h -1 .

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