Modified y, nh4y, and usy molecular sieves, methods of making and uses thereof

Abstract

The present disclosure relates to modified Y, NH4Y and ultra-stable Y molecular sieves, and a preparation method and use thereof. The modified Y molecular sieve prepared by using water-soluble fluoride as a modifier has a low silicon-aluminum ratio, and meanwhile, the adsorption, ion exchange and catalytic activity and other performances of the Y molecular sieve can be improved. The present disclosure uses the modified Y molecular sieve to prepare an NH4Y molecular sieve, which has a lower metal ion residue, improves the exchange depth, and has excellent ion exchange performance. The present disclosure uses the NH4Y molecular sieve to prepare an ultra-stable Y molecular sieve, which can maintain a low silicon-aluminum ratio, and meanwhile has more abundant secondary pores and higher catalytic activity.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of molecular sieve, in particular, to a modified Y-type molecular sieve, NH4Y molecular sieve and ultra-stable Y-type molecular sieve, and a preparation method and use thereof. BACKGROUND

[0002] Y-type molecular sieve has FAU topology and is one of 232 molecular sieve structures certified by the International Zeolite Association (IZA). The skeleton basis of Y-type molecular sieve is [SiO4] and [AlO4] tetrahedron, which are bonded together through shared oxygen atoms to form a developed three-dimensional pore structure. The intrinsic micropore aperture of Y-type molecular sieve is 12-membered ring, and the pore size reaches 0.74 nm, which is the largest among traditional zeolite molecular sieves.

[0003] In today's industry, Y-type molecular sieve is mainly synthesized by using chemical raw materials (such as caustic soda, industrial sodium aluminate, industrial water glass, etc.), which has the characteristics of mature process, easy to control technical conditions, and high product quality. In addition, due to the limited source and high price of industrial raw materials, researchers have begun to explore the technology of synthesizing Y-type molecular sieve from inorganic metal minerals (such as kaolin, diatomite, coal ash stone, etc.), and have made important achievements. At present, its synthesis technology is still developing and updating.

[0004] Y-type molecular sieve is widely used in catalytic cracking, hydrocracking, olefin alkylation and other fields as an important solid acid catalyst. In the field of catalysis, Y-type molecular sieve is well-known for its largest use, and its position cannot be shaken in a long period of time in the future. It has the advantages of regular pore structure, high stability and good reaction activity, but it also has many problems in reagent application, such as the narrow size of the micropore channel of the molecular sieve, which limits the in-vivo diffusion and transportation of large molecule reactants and products, and the reactants are difficult to contact the active center. At the same time, because of the long residence time in the pore channel, excessive cracking will occur to form carbon, thereby plugging the pore channel and accelerating the deactivation of the molecular sieve. Researchers have proposed that the introduction of mesopores into Y-type molecular sieve through certain means to form micro-mesoporous structure can solve the above problems.

[0005] The introduction of mesopores into Y-type molecular sieve mainly includes the following three ways: (1) direct synthesis of molecular sieve with larger size micropore; (2) preparation and self-assembly of molecular sieve nanoparticles, and use of particle accumulation to form intercrystalline mesopore; (3) introduction of mesopore into traditional microporous structure by post-treatment method, i.e. removing framework atoms. In the above method (1), the cost of the organic template used in the synthesis process is high, and it will cause environmental pollution, and the hydrothermal stability of the obtained molecular sieve is poor. In the above method (2), it is difficult to separate the nanoscale molecular sieve from the mother liquor. Therefore, it is a more suitable choice to introduce mesopores into the microporous structure by the post-treatment method in the method (3).

[0006] The post-treatment method is mainly divided into two kinds of removing framework aluminum and removing framework silicon. The method of removing framework aluminum can introduce mesoporous structure, which can increase the silica-alumina ratio of the molecular sieve, reduce the number of catalytic centers, and reduce the catalytic activity. In the field of catalysis, the method of removing framework silicon can introduce more abundant secondary pore structure while retaining the low silica-alumina ratio and not reducing the catalytic activity.

[0007] The traditional method for increasing the silica-alumina ratio of Y-type molecular sieve is to use alkali solution treatment. CN104843737A discloses a method for preparing Y-type molecular sieve with high silica-alumina ratio by pretreating zeolite molecular sieve with alkali solution. CN106669773A discloses a method for modifying Y-type molecular sieve by contacting unsaturated olefin with the calcined Y-type molecular sieve in an oxygen-free atmosphere to carry out carbon deposition reaction, and then adding the carbon-deposited Y-type molecular sieve into a pressure-resistant container containing sodium hydroxide solution. The Y-type molecular sieve prepared by these methods has a larger size of mesoporous distribution, which can provide more reaction space for macromolecules and improve the catalytic performance of the molecular sieve. However, this method has the problem of removing part of the framework aluminum while expanding the pore, which affects the catalytic activity of the catalyst. SUMMARY

[0008] The purpose of the present disclosure is to provide a modified Y-type molecular sieve, NH4Y molecular sieve and ultrastable Y-type molecular sieve, and a preparation method and use thereof.

[0009] The modified Y-type molecular sieve prepared by using water-soluble fluoride as a modifier has a low silica-alumina ratio, and can also improve the adsorption, ion exchange and catalytic activity of the Y-type molecular sieve.

[0010] The present disclosure further provides a NH4Y molecular sieve based on the modified Y-type molecular sieve, which has lower metal ion residues, improves the exchange depth, and has excellent ion exchange performance.

[0011] The present disclosure further provides an ultrastable Y-type molecular sieve based on the NH4Y molecular sieve, which can maintain a low silica-alumina ratio while having more abundant secondary pores and higher catalytic activity.

[0012] In order to achieve the above-mentioned purpose, the first aspect of the present disclosure provides a method for preparing a modified Y-type molecular sieve, the method comprising: mixing a Y-type molecular sieve raw material, a modifying agent, and deionized water according to a weight ratio of Y-type molecular sieve raw material: modifying agent: deionized water = (0.02-2):(0.01-2):(3-10) to obtain a raw material mixture; wherein the weight of the Y-type molecular sieve raw material is based on the dry weight of the Y-type molecular sieve; and subjecting the raw material mixture to a modification treatment under a modification reaction condition; wherein the modifying agent is a water-soluble fluoride.

[0013] Optionally, the weight ratio of the Y-type molecular sieve raw material: modifying agent: deionized water is (0.02-0.7):(0.02-1):(8-10).

[0014] Optionally, the modification reaction condition comprises a temperature of 10-100°C and a time of 0.5-4h; preferably a temperature of 30-60°C and a time of 0.5-2h; and optionally, the modification treatment is performed once or multiple times.

[0015] Optionally, the modifying agent is selected from one or more of HF, LiF, NaF, KF, and NH4F, preferably one or both of NaF and NH4F; optionally, the Y-type molecular sieve raw material has a framework silica-alumina ratio of no less than 4, preferably 4.2-7.5; optionally, the Y-type molecular sieve raw material is selected from one or more of NaY, KY, NH4Y, REY, and HY-type molecular sieves; preferably, the Y-type molecular sieve raw material is a NaY molecular sieve; and further preferably, the Y-type molecular sieve raw material is a Y-type molecular sieve separated from a crystallization mother liquor after crystallization synthesis, or a mixture of a Y-type molecular sieve containing a crystallization mother liquor.

[0016] The second aspect of the present disclosure provides a modified Y-type molecular sieve prepared by the method of the first aspect of the present disclosure.

[0017] Optionally, the modified Y-type molecular sieve has a crystallinity of 70-95%, preferably 75-90%; a silica-alumina ratio of 4.2-6, preferably 4.3-5.8; a specific surface area of 600-900m 2 / g, preferably 650-900m 2 / g; a total pore volume of 0.3-0.4mL / g, preferably 0.33-0.4mL / g; and a micropore volume of 0.25-0.35mL / g, preferably 0.27-0.32mL / g.

[0018] The third aspect of the present disclosure provides a method for preparing a NH4Y molecular sieve, the method comprising: subjecting the modified Y-type molecular sieve of the second aspect of the present disclosure to an ammonium ion exchange treatment, wherein the Y-type molecular sieve is a NaY molecular sieve.

[0019] Optionally, the ammonium ion exchange treatment comprises: filtering the slurry of the modified NaY molecular sieve, washing to a pH of 7.0-9.0, then contacting the obtained filter cake with an ammonium salt solution, and adding an acidic pH adjuster to adjust the obtained mixture to a pH of 2.0-6.5, preferably to a pH of 3.0-5.0; optionally, the ammonium ion exchange treatment is performed 1-5 times.

[0020] Optionally, the method further comprises: mixing the filter cake according to a weight ratio of Y-type molecular sieve: ammonium salt: deionized water = 1: (0.5-2): (3-30); and performing ammonium ion exchange on the obtained mixture under ion exchange conditions; wherein the Y-type molecular sieve is according to a dry basis weight, and the ion exchange conditions comprise: stirring at a temperature of 30-90℃ for 0.5-4h, preferably at a temperature of 60-90℃ for 0.5-2h.

[0021] Optionally, the ammonium salt is selected from one or more of ammonium sulfate, ammonium nitrate, ammonium chloride, ammonium carbonate, ammonium acetate, ammonium oxalate, ammonium phosphate, and ammonium citrate; preferably one or both of ammonium sulfate and ammonium nitrate; optionally, the acidic pH adjuster is an aqueous solution of an acid selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, carbonic acid, phosphoric acid, oxalic acid, and citric acid; preferably one or both of oxalic acid and phosphoric acid.

[0022] The fourth aspect of the present disclosure provides a NH4Y molecular sieve prepared by the method of the third aspect of the present disclosure.

[0023] The fifth aspect of the present disclosure provides a method for preparing a USY molecular sieve, the method comprising: performing hydrothermal USY treatment on the NH4Y molecular sieve of the fourth aspect of the present disclosure under hydrothermal USY treatment conditions.

[0024] Optionally, the hydrothermal USY treatment conditions comprise: placing the NH4Y molecular sieve in a hydrothermal kettle at a temperature of 500-700℃, and calcining under a 10-90% (by volume) water vapor atmosphere for 2-12h; preferably at a temperature of 550-700℃, for 2-8h, and under a 30-90% (by volume) water vapor atmosphere.

[0025] Optionally, the method further comprises: performing ammonium ion exchange treatment on the calcined molecular sieve; and optionally, subsequently performing the hydrothermal USY treatment again.

[0026] The sixth aspect of the present disclosure provides a USY molecular sieve prepared by the method of the fifth aspect of the present disclosure.

[0027] Optionally, the secondary pore volume of the USY molecular sieve is 0.02-0.1cm 3 / g, preferably 0.04-0.08 cm 3 / g.

[0028] The seventh aspect of the present disclosure provides a use of the ultra-stable Y-type molecular sieve according to the sixth aspect of the present disclosure in petroleum chemical industry; preferably, a use in catalytic cracking, alkylation, alkane isomerization, hydrogenation-dehydrogenation.

[0029] By the above technical solution, the present disclosure first provides a method for preparing a modified Y-type molecular sieve, which modifies the Y-type molecular sieve by using water-soluble fluoride as a modifier, so that the framework of the Y-type molecular sieve can be changed, the framework silica-alumina ratio can be reduced, and the adsorption, ion exchange and catalytic activity of the Y-type molecular sieve can be improved, and the subsequent ammonium ion exchange treatment of the modified Y-type molecular sieve is facilitated. The modified Y-type molecular sieve prepared according to the method has high crystallinity, low silica-alumina ratio, large specific surface area and large total pore volume, and has higher catalytic activity and adsorption performance.

[0030] The present disclosure also provides a method for preparing an NH4Y molecular sieve, which exchanges ammonium ions on the modified NaY molecular sieve, has lower metal ion residues, and improves the exchange depth. The NH4Y molecular sieve prepared according to the method has excellent ion exchange performance, and can also be used as a new raw material for Y-type molecular sieve modification.

[0031] The present disclosure also provides a method for preparing an ultra-stable Y-type molecular sieve, and the ultra-stable Y-type molecular sieve prepared according to the method has more abundant secondary pores while maintaining a low silica-alumina ratio, thereby improving the catalytic activity of the ultra-stable Y-type molecular sieve.

[0032] Other features and advantages of the present disclosure will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings are included to provide a further understanding of the present disclosure, and constitute a part of the specification, and are used together with the following specific embodiments to explain the present disclosure, but do not constitute a limitation on the present disclosure. In the drawings:

[0034] Figure 1 BET adsorption curve of sample A1 in Example 1. DETAILED DESCRIPTION

[0035] The specific embodiments of the present disclosure are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0036] The present inventors have found in the experimental research that the use of water-soluble fluoride as a modifier can selectively etch and remove the silicon elements of the Y-type molecular sieve framework without destroying the framework structure of the Y-type molecular sieve, and is also conducive to improving the secondary pore structure of the molecular sieve and improving the catalytic activity of the Y-type molecular sieve.

[0037] The first aspect of the present disclosure provides a method for preparing a modified Y-type molecular sieve, which comprises:

[0038] The Y-type molecular sieve raw material, the modifier, and deionized water are mixed in a weight ratio of Y-type molecular sieve raw material: modifier: deionized water = (0.02-2): (0.01-2): (3-10) to obtain a raw material mixture; wherein the weight of the Y-type molecular sieve raw material is based on the dry weight of the Y-type molecular sieve;

[0039] The raw material mixture is subjected to modification treatment under modification reaction conditions; wherein the modifier is a water-soluble fluoride.

[0040] The first aspect of the present disclosure provides a method for preparing a modified Y-type molecular sieve, which comprises using a water-soluble fluoride as a modifier to modify the Y-type molecular sieve, which can change the framework of the Y-type molecular sieve, reduce the framework silicon-aluminum ratio, and improve the adsorption, ion exchange, and catalytic activity of the Y-type molecular sieve, and is conducive to subsequent ammonium ion exchange treatment of the modified Y-type molecular sieve.

[0041] In a preferred embodiment, the weight ratio of the Y-type molecular sieve raw material: modifier: deionized water is (0.02-0.7): (0.02-1): (8-10). According to this embodiment, the performance of the modified Y-type molecular sieve can be further improved.

[0042] In a specific embodiment, the modifier (water-soluble fluoride) can be prepared into a modifier solution with deionized water before the modification treatment. Then the modifier solution and the Y-type molecular sieve are mixed to obtain the raw material mixture.

[0043] In the present disclosure, the molecular sieve mass or weight ratio involved in each treatment stage is based on the dry basis.

[0044] In an embodiment, the modification reaction conditions include a temperature of 10-100°C and a time of 0.5-4h; preferably a temperature of 30-60°C and a time of 0.5-2h. In a specific embodiment, mechanical stirring can be used during the modification treatment, and the stirring rate can be adjusted according to the degree of modification treatment.

[0045] In a specific embodiment, the modification process can be repeated one or more times to further improve the silicon-aluminum ratio of the modified Y-type molecular sieve.

[0046] In one embodiment, the modifier is selected from one or more of HF, LiF, NaF, KF, NH4F, preferably one or both of NaF and NH4F.

[0047] In one embodiment, the Y-type molecular sieve raw material has a framework silica-alumina ratio of not less than 4, preferably 4.2-7.5.

[0048] In the present disclosure, the "silica-alumina ratio" refers to the molar ratio of SiO2 / Al2O3 on the molecular sieve framework.

[0049] In one embodiment, the Y-type molecular sieve raw material is selected from one or more of NaY, KY, NH4Y, REY, and HY-type molecular sieves; preferably, the Y-type molecular sieve raw material is NaY molecular sieve; further preferably, the Y-type molecular sieve raw material is Y-type molecular sieve separated from the crystallization mother liquor after crystallization synthesis, or a mixture of Y-type molecular sieve containing the crystallization mother liquor.

[0050] In one specific embodiment, the Y-type molecular sieve raw material is NaY molecular sieve, which can be NaY raw powder synthesized by conventional methods in the art, or a mixture of NaY molecular sieve containing the crystallization mother liquor.

[0051] The second aspect of the present disclosure provides a modified Y-type molecular sieve prepared by the method of the first aspect of the present disclosure.

[0052] The modified Y-type molecular sieve provided by the present disclosure has high crystallinity, low silica-alumina ratio, large specific surface area, and large total pore volume, and has higher catalytic activity and adsorption performance; the modified Y-type molecular sieve provides a new starting material for subsequent further modification treatment, thereby providing a raw material with excellent performance for the adsorbent industry, the catalyst industry, and the like.

[0053] In one specific embodiment, the modified Y-type molecular sieve has a crystallinity of 70-95%, preferably 75-90%; a silica-alumina ratio of 4.2-6, preferably 4.3-5.8; a specific surface area of 600-900 m 2 / g, preferably 650-900 m 2 / g; a total pore volume of 0.3-0.4 mL / g, preferably 0.33-0.4 mL / g; and a micropore volume of 0.25-0.35 mL / g, preferably 0.27-0.32 mL / g. In the present disclosure, the "micropore" refers to a pore with a pore size of less than 2 nm. In the present disclosure, the crystallinity represents the numerical value of the crystalline phase and the non-crystalline phase in the material in mass fraction.

[0054] The third aspect of the present disclosure provides a method for preparing NH4Y molecular sieve, which comprises: subjecting the modified Y molecular sieve of the second aspect of the present disclosure to ammonium ion exchange treatment, wherein the Y molecular sieve raw material is NaY molecular sieve.

[0055] The method for preparing NH4Y molecular sieve provided by the present disclosure can achieve lower metal ion residue and improve exchange depth by subjecting the modified NaY molecular sieve to ammonium ion exchange treatment.

[0056] In an embodiment, the ammonium ion exchange treatment comprises: filtering and washing the slurry of the modified NaY molecular sieve to a pH of 7.5-9.0, then contacting the obtained filter cake with an ammonium salt solution, and adding an acidic pH adjuster to adjust the obtained mixture to a pH of 2.0-6.5, preferably to a pH of 3.0-5.0.

[0057] In an embodiment, the ammonium ion exchange treatment can be performed 1-5 times.

[0058] In a specific embodiment, mechanical stirring can be used during the ammonium ion exchange treatment. The stirring rate can be adjusted according to the treatment degree.

[0059] In an embodiment, the method further comprises: mixing the filter cake according to the weight ratio of Y molecular sieve raw material: ammonium salt: deionized water = 1: (0.5-2): (3-30); and subjecting the obtained mixture to ammonium ion exchange under ion exchange conditions.

[0060] In an embodiment, the Y molecular sieve is according to the dry weight, and the ion exchange conditions comprise: stirring at a temperature of 30-90°C for 0.5-4h; preferably, at a temperature of 60-90°C for 0.5-2h.

[0061] In an embodiment, the ammonium salt is selected from one or more of ammonium sulfate, ammonium nitrate, ammonium chloride, ammonium carbonate, ammonium acetate, ammonium oxalate, ammonium phosphate, and ammonium citrate; and preferably one or both of ammonium sulfate and ammonium nitrate.

[0062] In an embodiment, the acidic pH adjuster is an aqueous solution of an acid selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, carbonic acid, phosphoric acid, oxalic acid, and citric acid; and preferably one or both of oxalic acid and phosphoric acid.

[0063] The fourth aspect of the present disclosure provides an NH4Y molecular sieve prepared by the method of the third aspect of the present disclosure. The NH4Y molecular sieve has excellent ion exchange performance and can also be used as a new type of raw material for Y molecular sieve modification.

[0064] The fifth aspect of the present disclosure provides a method for preparing an ultra-stable Y-type molecular sieve, which comprises:

[0065] The NH4Y molecular sieve of the fourth aspect of the present disclosure is subjected to hydrothermal ultra-stable treatment under hydrothermal ultra-stable treatment conditions.

[0066] In one embodiment, the hydrothermal ultra-stable treatment conditions comprise placing the NH4Y molecular sieve in a hydrothermal kettle at a temperature of 500-700℃ and calcining under a 10-90% (volume) water vapor atmosphere for 2-12h; preferably, the temperature is 550-700℃, the calcination time is 2-8h, and the water vapor atmosphere is 30-90% (volume).

[0067] In one specific embodiment, the hydrothermal ultra-stable treatment can be performed once or repeatedly, for example, 1-2 times.

[0068] In one embodiment, the method further comprises subjecting the calcined molecular sieve to ammonium ion exchange treatment; optionally, followed by again performing the hydrothermal ultra-stable treatment.

[0069] In one specific embodiment, the NH4Y molecular sieve of the fourth aspect of the present disclosure is subjected to first hydrothermal ultra-stable treatment under hydrothermal ultra-stable treatment conditions; then the obtained molecular sieve is subjected to ammonium ion exchange treatment again, and the ammonium ion exchange treatment conditions can be the same as those described in the second aspect of the present disclosure; further, the obtained molecular sieve can be subjected to second hydrothermal ultra-stable treatment under hydrothermal ultra-stable treatment conditions to obtain an ultra-stable Y-type molecular sieve. Further, the hydrothermal ultra-stable treatment and the ammonium ion exchange treatment can be alternately performed multiple times in the present disclosure to obtain an ultra-stable Y-type molecular sieve. In this embodiment, the thermal stability of the molecular sieve can be effectively improved.

[0070] The sixth aspect of the present disclosure provides an ultra-stable Y-type molecular sieve prepared by the method of the fifth aspect of the present disclosure.

[0071] The ultra-stable Y-type molecular sieve provided by the present disclosure has more abundant secondary pores while maintaining a low silicon-aluminum ratio, thereby improving the catalytic activity of the ultra-stable Y-type molecular sieve.

[0072] In one specific embodiment, the secondary pore volume of the ultra-stable Y-type molecular sieve is 0.02-0.1cm 3 / g, preferably 0.04-0.08cm 3 / g. In the present disclosure, the "secondary pore volume" is obtained by subtracting the micropore volume of the molecular sieve from the total pore volume of the molecular sieve.

[0073] The seventh aspect of the present disclosure provides a use of the ultra-stable Y-type molecular sieve according to the sixth aspect of the present disclosure in petroleum chemical industry; preferably, a use in catalytic cracking, alkylation, alkane isomerization, hydrogenation-dehydrogenation.

[0074] The present application is further illustrated in detail by the following examples, but the present application is not limited thereto.

[0075] In the following examples and comparative examples:

[0076] The total pore volume of the molecular sieve is determined by low-temperature nitrogen adsorption method, and the pores with a diameter in the range of 2-60 nm in the molecular sieve framework are selected to calculate the volume of the secondary pores;

[0077] The specific surface area of the molecular sieve is determined by GB / T 5816-1995 according to the method for calculating the total surface area of the sample according to the BET formula;

[0078] The micropore volume (pores with a diameter less than 2 nm) of the molecular sieve is determined by SH / T 0571-1993 (2004) by the method for calculating the matrix (mesopore) micropore volume of the sample by t-plot method;

[0079] The unit cell constant and the relative crystallinity of the molecular sieve are determined by X-ray powder diffraction method, and the RIPP 145-90 standard method (see “Petroleum Chemical Industry Analysis Method” RIPP Test Method, Yang Cuiding et al., Science Press, 1990 edition) is used;

[0080] The framework silica-alumina ratio (molar ratio of SiO2 / Al2O3) is determined by solid-state nuclear magnetic resonance method.

[0081] The main raw materials used in the following examples and comparative examples are as follows:

[0082] Ammonium fluoride, National Pharmaceutical Group Chemical Reagent Co., Ltd., analytical pure;

[0083] Ammonium chloride, National Pharmaceutical Group Chemical Reagent Co., Ltd., analytical pure;

[0084] Sodium fluoride, National Pharmaceutical Group Chemical Reagent Co., Ltd., analytical pure;

[0085] Hydrochloric acid, National Pharmaceutical Group Chemical Reagent Co., Ltd., 37%;

[0086] NaY molecular sieve, Catalyst Factory of Nankai University, industrial product;

[0087] HY molecular sieve, Catalyst Factory of Nankai University, industrial product;

[0088] USY molecular sieve, Catalyst Factory of Nankai University, industrial product;

[0089] Kaolin, Shanghai Kaijin Chemical Industry Co., Ltd., industrial product;

[0090] Aluminum sol, Jinan Xinsen Yuan Chemical Co., Ltd., industrial product.

[0091] Examples 1-4 are used to illustrate the method for preparing modified Y-type molecular sieves.

[0092] Example 1

[0093] 3 g of modifier NH4F was dissolved in 997 g of deionized water, and after stirring to uniformity, the temperature was raised to 60°C. 100 g of NaY molecular sieve (crystallinity: 90%, framework silica-alumina ratio: 5.4, specific surface area: 900 m 2 / g, total pore volume: 0.3 mL / g, micropore volume: 0.28 mL / g) was added to the above solution, ultrasonic dispersion and stirring was carried out at 60°C for 2 h, and after filtration, washing, and drying, a modified NaY molecular sieve was obtained, which was recorded as sample A1.

[0094] Example 2

[0095] 5 g of modifier NH4F was dissolved in 995 g of deionized water, and after stirring to uniformity, the temperature was raised to 60°C. 80 g of NaY molecular sieve (crystallinity: 90%, framework silica-alumina ratio: 5.4, specific surface area: 900 m 2 / g, total pore volume: 0.3 mL / g, micropore volume: 0.28 mL / g) was added to the above solution, ultrasonic dispersion and stirring was carried out at 60°C for 2 h, and after filtration, washing, and drying, a modified NaY molecular sieve was obtained, which was recorded as sample A2.

[0096] Example 3

[0097] 3 g of modifier NH4F was dissolved in 997 g of deionized water, and after stirring to uniformity, the temperature was raised to 60°C. 100 g of HY molecular sieve (crystallinity: 75%, framework silica-alumina ratio: 5.2, specific surface area: 680 m 2 / g, Na2O: 0.8%) was added to the above solution, ultrasonic dispersion and stirring was carried out at 60°C for 2 h, and after filtration, washing, and drying, a modified HY molecular sieve was obtained, which was recorded as sample A3.

[0098] Example 4

[0099] 3 g of modifier NH4F was dissolved in 997 g of deionized water, and after stirring to uniformity, the temperature was raised to 60°C. 50 g of NaY molecular sieve (crystallinity: 90%, framework silica-alumina ratio: 5.4, specific surface area: 900 m 2 / g, total pore volume: 0.3 mL / g, micropore volume: 0.28 mL / g) was added to the above solution, ultrasonic dispersion and stirring was carried out at 60°C for 2 h, and after filtration, washing, and drying, a modified NaY molecular sieve was obtained, which was recorded as sample A4.

[0100] Example 5-7 are used to illustrate a method for preparing NH4Y molecular sieve.

[0101] Example 5

[0102] Take 30 g of sample A1, add 30 g of ammonium chloride to 300 g of distilled water, stir until uniform, then stir at 60°C for 1 h to perform ammonium ion exchange. During the exchange process, use 1 mol / L hydrochloric acid to adjust the pH value of the exchange slurry to 3.0 and keep it. After the exchange is completed, filter and wash to obtain NH4Y molecular sieve, which is recorded as sample B1.

[0103] Example 6

[0104] The same preparation method as in Example 5 is used, except that sample A1 is replaced by sample A4, to obtain NH4Y molecular sieve, which is recorded as sample B2.

[0105] Example 7

[0106] The same preparation method as in Example 6 is used, except that the ammonium ion exchange is performed at 30°C for 1 h, to obtain NH4Y molecular sieve, which is recorded as sample B3.

[0107] Comparative Example 1

[0108] The same preparation method as in Example 5 is used, except that sample A1 is replaced by a commercially available NaY molecular sieve, to obtain NH4Y molecular sieve, which is recorded as sample D1.

[0109] Examples 8-10 are used to illustrate a method for preparing USY molecular sieve.

[0110] Example 8

[0111] Sample B1 is calcined at 650°C under a 100% water vapor atmosphere for 2 h, and the obtained sample is subjected to ammonium ion exchange again. During the second ammonium ion exchange, the molecular sieve (dry basis) : ammonium chloride : deionized water = 1 : 1 : 10, and 1 mol / L hydrochloric acid is used to adjust the pH value to 2.5 and keep it for 1 h. USY molecular sieve is obtained, which is recorded as sample C1.

[0112] Example 9

[0113] The same preparation method as in Example 8 is used, except that sample B1 is replaced by sample B2, to obtain USY molecular sieve, which is recorded as sample C2.

[0114] Example 10

[0115] The same preparation method as in Example 9 is used, except that the calcination temperature of sample B2 is 500°C and the calcination time is 2 h, to obtain USY molecular sieve, which is recorded as sample C3.

[0116] Comparative Example 2

[0117] The same preparation method as in Example 8 was used, except that sample B1 was replaced by sample D1, to obtain a Y-type molecular sieve, which is denoted as sample D2.

[0118] Test Example 1

[0119] This test example is used to illustrate the structural performance of the molecular sieve products of the above examples and comparative examples.

[0120] The samples prepared in the above examples and comparative examples, as well as commercially available NaY molecular sieve, HY molecular sieve and USY molecular sieve, were respectively measured for crystallinity, framework silica-alumina ratio, specific surface area, total pore volume and micropore volume, and the measurement results are shown in Table 1, wherein the BET curve of sample A1 is shown in Figure 1 .

[0121] Table 1

[0122]

[0123] wherein the secondary pore volume = total pore volume - micropore volume.

[0124] As can be seen from the above table, compared with commercially available NaY molecular sieve, HY molecular sieve and USY molecular sieve, the modified Y-type molecular sieve, NH4Y molecular sieve and Y-type molecular sieve provided by the present application can effectively increase the total pore volume and secondary pore volume of the molecular sieve. Further, as can be seen from the above table, when the modified Y-type molecular sieve is prepared, the weight ratio of Y-type molecular sieve raw material: modifier: deionized water satisfies (0.02-0.7):(0.02-1):(8-10) (sample A4), and the NH4Y molecular sieve (sample B2) and Y-type molecular sieve (sample C2) prepared based on the Y-type molecular sieve raw material have greater specific surface area, total pore volume and secondary pore volume.

[0125] Test Example 2

[0126] This test example is used to illustrate the catalytic performance of the catalyst prepared by using the molecular sieve products of the above examples and comparative examples as active components.

[0127] The molecular sieves prepared in the above examples and comparative examples, as well as commercially available NaY molecular sieve, HY molecular sieve and USY molecular sieve, were respectively used as catalyst active components, kaolin was used as a matrix, and aluminum sol was used as a binder, the molecular sieve (dry basis), kaolin (dry basis) and aluminum sol (solid content) were mixed uniformly at a ratio of 35:50:15, and then were sprayed, dried, and made into microspherical catalysts, and the reaction performance of the catalysts was evaluated on a small fixed fluidized bed catalytic cracking device, and the results are shown in Table 2-1 and Table 2-2.

[0128] Wherein, the catalyst is aged at 700℃ for 4 hours with 100% steam before evaluation, the feedstock is Daqing waxy oil mixed with 30wt% vacuum residue, the reaction temperature is 480℃, and the space velocity is 16h -1 , and the catalyst / oil ratio is 4.0.

[0129] Table 2-1

[0130]

[0131] Table 2-2

[0132]

[0133]

[0134] The data in Tables 2-1 and 2-2 show that the catalysts prepared by using the NH4Y zeolite and the ultrastable Y zeolite prepared by the method provided in the present application as the active component have stronger heavy oil conversion capacity and higher light oil yield compared with the catalysts prepared by using the commercial conventional NaY zeolite, HY zeolite and USY zeolite as the active component.

[0135] Compared with D1 (NH4Y zeolite prepared from the commercial NaY zeolite), the catalyst prepared by using the NH4Y zeolite (B1-B3, prepared by first modifying the zeolite to obtain a modified Y zeolite and then preparing the NH4Y zeolite) prepared by the method provided in the present application as the active component has stronger heavy oil conversion capacity and higher light oil yield.

[0136] Compared with D2 (ultrastable Y zeolite prepared from D1), the catalyst prepared by using the ultrastable Y zeolite (C1-C3) prepared by the method provided in the present application as the active component has stronger heavy oil conversion capacity and higher light oil yield.

[0137] Comparing the modified Y zeolites A1-A4 prepared in Examples 1-4, it can be seen that the catalyst prepared by using A4 (prepared by using the Y zeolite raw material, the modifier and the deionized water in a weight ratio of (0.02-0.7):(0.02-1):(8-10) as the active component has stronger heavy oil conversion capacity and higher light oil yield. Further, comparing B2 and B3, the B2 prepared by using the ammonium ion exchange temperature of 60-90℃ has stronger heavy oil conversion capacity and higher light oil yield; comparing C2 and C3, the C2 prepared by using the calcination temperature of 550-700℃ has stronger heavy oil conversion capacity and higher light oil yield.

[0138] The present disclosure is not limited to the specific details of the above-described embodiments, and various simple modifications can be made to the technical solutions of the present disclosure within the scope of the technical concept of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0139] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present disclosure.

[0140] In addition, any combination of various different embodiments of the present disclosure can also be made, as long as it does not deviate from the idea of the present disclosure, and it should also be considered as disclosed by the present disclosure.

Claims

1. The application of an ultrastable Y-type molecular sieve in catalytic cracking, characterized in that, The ultrastable Y-type molecular sieve is prepared by a method including the following steps: Hydrothermal ultrastability treatment was performed on NH4Y molecular sieves. The hydrothermal ultra-stable treatment conditions include: placing the NH4Y molecular sieve in a hydrothermal autoclave at a temperature of 500-700℃ and calcining it for 2-12 hours under a 10-90% volume water vapor atmosphere. The NH4Y molecular sieve is prepared by a method comprising the following steps: The modified Y-type molecular sieve is subjected to ammonium ion exchange treatment, wherein the Y-type molecular sieve raw material is NaY molecular sieve; the ammonium ion exchange treatment includes: filtering and washing the slurry of the modified NaY molecular sieve to a pH of 7.0-9.0, then contacting the resulting filter cake with an ammonium salt solution, and adding an acidic pH adjuster to adjust the pH of the resulting mixture to 2.0-6.5; The modified Y-type molecular sieve is prepared by a method comprising the following steps: The Y-type molecular sieve raw material, the modifier, and deionized water are mixed according to the weight ratio of Y-type molecular sieve raw material: modifier: deionized water = (0.02-0.7):(0.02-1):(8-10) to obtain a raw material mixture; wherein the weight of the Y-type molecular sieve raw material is based on the dry weight of the Y-type molecular sieve; the raw material mixture is modified under modification reaction conditions; wherein the modifier is a water-soluble fluoride; wherein the modified Y-type molecular sieve has a silica-alumina ratio of 4.2-6 and a specific surface area of ​​600-900 m². 2 / g; total pore volume is 0.3-0.4 mL / g; micropore volume is 0.25-0.35 mL / g.

2. The use according to claim 1, characterized in that, The modification reaction conditions include: a temperature of 10-100℃ and a time of 0.5-4h.

3. The use according to claim 2, characterized in that, The modification reaction conditions include: a temperature of 30-60℃ and a time of 0.5-2h.

4. The use according to claim 1, characterized in that, The modification process may be performed once or multiple times.

5. The use according to claim 1, characterized in that, The modifier is selected from one or more of HF, LiF, NaF, KF, and NH4F.

6. The use according to claim 5, characterized in that, The modifier is selected from one or two of NaF and NH4F.

7. The use according to claim 1, characterized in that, The skeleton silicon-aluminum ratio of the Y-type molecular sieve raw material is not less than 4.

8. The use according to claim 7, characterized in that, The skeleton silicon-to-aluminum ratio of the Y-type molecular sieve raw material is 4.2-7.

5.

9. The use according to claim 1, characterized in that, The Y-type molecular sieve raw material is selected from one or more of NaY, KY, NH4Y, REY, and HY type molecular sieves.

10. The use according to claim 9, characterized in that, The Y-type molecular sieve raw material is NaY molecular sieve.

11. The use according to claim 9, characterized in that, The Y-type molecular sieve raw material is a Y-type molecular sieve separated from the crystallization mother liquor after crystallization synthesis, or a mixture of Y-type molecular sieves containing the crystallization mother liquor.

12. The use according to claim 1, characterized in that, The modified Y-type molecular sieve has a crystallinity of 70-95%.

13. The use according to claim 12, characterized in that, The modified Y-type molecular sieve has a crystallinity of 75-90%, a silica-alumina ratio of 4.3-5.8, and a specific surface area of ​​650-900 m². 2 / g; total pore volume is 0.33-0.4 mL / g; micropore volume is 0.27-0.32 mL / g.

14. The use according to claim 1, characterized in that, The ammonium ion exchange treatment includes: adding an acidic pH adjuster to adjust the pH of the resulting mixture to 3.0-5.

0.

15. The use according to claim 14, characterized in that, The ammonium ion exchange treatment is performed 1-5 times.

16. The use according to claim 1, characterized in that, The method also includes: The filter cake was mixed with modified NaY molecular sieve, ammonium salt and water in a weight ratio of 1:(0.5-2):(3-30); the resulting mixture was subjected to ammonium ion exchange under ion exchange conditions. The Y-type molecular sieve, on a dry basis, is subjected to ion exchange under the following conditions: stirred at a temperature of 30-90°C for 0.5-4 hours.

17. The use according to claim 16, characterized in that, The ion exchange conditions include a temperature of 60-90℃ and a time of 0.5-2h.

18. The use according to claim 1, characterized in that, The ammonium salt is selected from one or more of ammonium sulfate, ammonium nitrate, ammonium chloride, ammonium carbonate, ammonium acetate, ammonium oxalate, ammonium phosphate, and ammonium citrate.

19. The use according to claim 18, characterized in that, The ammonium salt is selected from one or both of ammonium sulfate and ammonium nitrate.

20. The use according to claim 1, characterized in that, The acidic pH adjuster is an aqueous solution of an acid, which is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, carbonic acid, phosphoric acid, oxalic acid, and citric acid.

21. The use according to claim 20, characterized in that, The acid is selected from one or both of oxalic acid and phosphoric acid.

22. The use according to claim 1, characterized in that, The hydrothermal ultra-stable treatment conditions include: a temperature of 550-700℃, a calcination time of 2-8 hours, and a 30-90% volume water vapor atmosphere.

23. The use according to claim 1, characterized in that, The method also includes: The molecular sieve obtained by calcination is subjected to ammonium ion exchange treatment.

24. The use according to claim 23, characterized in that, The hydrothermal ultra-stable treatment was then performed again.

25. The use according to claim 1, characterized in that, The secondary pore volume of this ultrastable Y-type molecular sieve is 0.02-0.1 cm³. 3 / g.

26. The use according to claim 25, characterized in that, The secondary pore volume of this ultrastable Y-type molecular sieve is 0.04-0.08 cm³. 3 / g.

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