Catalytic cracking aids, processes for their preparation and use

Abstract

The application provides a catalytic cracking aid and a preparation method and application thereof. The raw material of the catalytic cracking aid comprises, based on 100% of the weight of the raw material of the catalytic cracking aid, 15-55% of modified ZSM-5 molecular sieve, 10-55% of clay, 3-20% of an aluminum source and 5-20% of phosphorus from a second modifier, wherein the weight of the modified ZSM-5 molecular sieve, the clay and the aluminum source is calculated on a dry basis, and the weight of the phosphorus is calculated as an oxide; the modified ZSM-5 molecular sieve is obtained by modifying a raw material ZSM-5 molecular sieve by using a first modifier comprising a titanium source and a phosphorus source. The application further provides a preparation method of the catalytic cracking aid and application of the catalytic cracking aid in a catalytic cracking process. The catalytic cracking aid provided by the application can promote the conversion of heavy oil in the catalytic cracking process, reduce the yield of heavy oil, produce more low-carbon olefins, improve the total liquid yield, reduce the coke formation and has excellent cracking reaction selectivity and use performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil refining catalyst and adjuvant technology, in particular to a catalytic cracking adjuvant and its preparation method and application. BACKGROUND

[0002] In the production process of polyolefin industry, the widely used catalyst is mainly Ziegler-Natta catalyst, which is a titanium-based catalyst. For the preparation of titanium-based polyolefin catalyst, for example, CN 102336851 A discloses a propylene polymerization catalyst, which comprises magnesium, titanium, halogen and a mixture of internal electron donor compounds diisobutyl phthalate, diethyl phthalate or di-n-butyl phthalate and succinate; Chinese patent CN 107434832 B discloses a propylene polymerization catalyst, which mainly consists of alcohol magnesium compound, titanium compound and phosphate ester electron donor compound. The common method for preparing titanium-based catalyst at present is: first, the preparation of halogenated magnesium alcoholate, for example, after the halogenated magnesium and alcohol are co-heated and dissolved, high-pressure spraying or high-speed stirring is carried out, and the method of solidifying into microspherical particles in cooling medium is adopted, see the relevant description in CN1110281A for specific steps; then, the halogenated magnesium alcoholate particles are reacted with halogen-containing compounds such as titanium tetrachloride to prepare magnesium-supported catalyst, during which various promoters can be added for modification. In the above catalyst preparation process, a large amount of titanium tetrachloride is needed, and the excess ratio is large, and at the same time, the obtained solid catalyst components need to be washed with hydrocarbon solvents (such as hexane) to remove the un-loaded titanium tetrachloride therein. Therefore, in the production process of polyolefin catalyst, after the catalyst solid is separated and precipitated, a large amount of catalyst mother liquor containing at least one of titanium tetrachloride, unreacted hydrocarbons, unreacted halogenated alkoxy titanium, and unreacted esters will be produced. A large amount of waste liquid containing titanium tetrachloride is produced in the preparation process of titanium-based polypropylene catalyst, in which the content of titanium tetrachloride is about 80%-95% (by weight), the content of titanium alkoxy complex is about 2%-5%, and the rest is carbon hydride including hexane and esters, in which hexane accounts for most of the carbon hydride. If the above waste liquid containing titanium tetrachloride is discharged into the environment, it will inevitably cause environmental pollution and resource waste. At present, there is a lack of simple and effective method for recycling and treating waste liquid containing titanium tetrachloride to reduce environmental pollution.

[0003] Further, the thermal stability of the existing ZSM-5 molecular sieve is not high, even after modification by known methods, the thermal stability of the ZSM-5 molecular sieve is still not ideal, which is not conducive to the use of the molecular sieve, especially the application of the molecular sieve as a cracking catalyst. In the prior art, for example, CN102114429A discloses a method for increasing the B acid amount of ZSM-5 molecular sieve and achieving increased production of low carbon olefins, which is achieved by simultaneously modifying the ZSM-5 molecular sieve with iron and titanium, and the mass ratio of iron to titanium in the modified molecular sieve is 0.3-3:1, so that the catalytic reactivity of the molecular sieve is improved, the conversion of long-chain alkanes and aromatic hydrocarbons with long-chain alkyl side chains such as cumene is promoted, and the yield of low carbon olefins is increased. US5171921 discloses a method for modifying ZSM-5 molecular sieve, which comprises ammonium exchange, drying and calcination of the synthesized ZSM-5 molecular sieve, and then modifying, drying and calcining with phosphoric acid to obtain a ZSM-5 molecular sieve containing phosphorus. In the prior art, the problem of treating waste liquid containing titanium tetrachloride generated in the preparation process of titanium-based polypropylene catalyst is not involved, and the modified ZSM-5 molecular sieve does not involve improving the stability of the molecular sieve or the stability of the molecular sieve is not ideal.

[0004] As for the existing catalytic cracking aid, CN106179470A discloses a preparation method of a catalytic cracking aid for increasing the octane number of gasoline, the preparation steps of which are as follows: (1) ZSM-5 molecular sieve is slurried with water, the solid content is controlled to be 35-45wt%, a certain proportion of modifier is added and stirred uniformly; (2) a certain proportion of pseudo-boehmite is added to the slurry of step (1), and the pH value range is adjusted to 1.8-2.3 with acid solution; (3) a certain concentration of pseudo-boehmite slurry is added to a certain concentration of phosphoric acid solution, the reaction temperature is controlled to be 50-65℃, and the reaction time is >5h; (4) a certain amount of water is added to the slurry of step (3), and then kaolin is added and stirred uniformly; (5) the slurry of step (2) is added to the slurry of step (4) and stirred uniformly; (6) spray drying, and the aid is obtained. Industrial test proves that the aid accounts for 3-10wt% of the system inventory, the research octane number can be increased by 1-3 units, and the propylene yield is increased by 1-4 percentage points. The silicon-aluminum ratio of the ZSM-5 molecular sieve in the aid is 100-300. Although the performance of the above-mentioned aid is improved, the adverse effects of high heavy oil yield, high coke formation and low total liquid yield caused by the ZSM-5 molecular sieve aid in the heavy oil cracking process also need to be further improved.

[0005] At present, it is still necessary to provide a new aid preparation technology which has a simple and feasible preparation process and excellent performance. SUMMARY

[0006] In order to solve the above problems, the present application aims to provide a catalytic cracking aid and its preparation method and application. The catalytic cracking aid can promote heavy oil conversion, reduce heavy oil yield, reduce the tendency of coke formation, and improve the yield of low-carbon olefins, and has excellent reaction selectivity and use performance.

[0007] In order to achieve the above-mentioned purpose, the present application provides a catalytic cracking aid, wherein the raw materials of the catalytic cracking aid, based on 100% by weight of the raw materials of the catalytic cracking aid, include: 15%-55% of modified ZSM-5 molecular sieve, 10%-55% of clay, 3%-20% of aluminum source, and 5%-20% of phosphorus from a second modifier, wherein the weight of the modified ZSM-5 molecular sieve, clay and aluminum source is calculated on a dry basis, and the weight of the phosphorus is calculated as an oxide (phosphorus pentoxide);

[0008] The preparation method of the modified ZSM-5 molecular sieve includes: mixing the raw material ZSM-5 with the titanium source of the first modifier to form a mixed solution, performing first calcination, or using an impregnation solution containing the titanium source to sufficiently impregnate the raw material ZSM-5 molecular sieve, drying and performing first calcination; mixing the product of the first calcination with the phosphorus source of the first modifier, and performing second calcination to obtain the modified ZSM-5 molecular sieve; and the first modifier includes the titanium source and the phosphorus source.

[0009] In the modified ZSM-5 molecular sieve, the titanium source and the phosphorus source in the first modifier can jointly modify the ZSM-5 molecular sieve and cooperatively improve the acid distribution and hydrothermal stability in the ZSM-5 molecular sieve, thereby promoting heavy oil conversion in the catalytic process in which the catalytic cracking aid participates and reducing the amount of coke.

[0010] In the above-mentioned modified ZSM-5 molecular sieve, based on 100% by weight of the total weight of the modified ZSM-5 molecular sieve, the modified ZSM-5 molecular sieve includes 0.2%-25% titanium and 0.2%-6% phosphorus, wherein the weight of the titanium and the phosphorus is calculated as an oxide (titanium dioxide and phosphorus pentoxide), respectively.

[0011] In the above-mentioned modified ZSM-5 molecular sieve, based on the oxide of titanium, the weight content of titanium from the first modifier in the modified ZSM-5 molecular sieve is 0.2%-25%, and further can be 0.5%-15%. Specifically, based on the oxide of titanium, the weight content of the titanium in the modified ZSM-5 molecular sieve can be 0.2%, 0.5%, 1%, 5%, 10%, 15%, 20%, 25%, and the like, and a range with any two of the above-mentioned specific values as endpoints.

[0012] In the modified ZSM-5 molecular sieve, the phosphorus from the first modifier has a weight content of 0.2%-6%, further 0.5%-6%, in terms of oxide of phosphorus in the modified ZSM-5 molecular sieve. Specifically, the weight content of the phosphorus in the modified ZSM-5 molecular sieve can be 0.2%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, and the like specific values and ranges with any two of the above specific values as endpoints.

[0013] In the preparation method of the modified ZSM-5 molecular sieve, the modified ZSM-5 molecular sieve can further include a modified metal element, and correspondingly, the first modifier can further include a modified metal source. The modified metal element can modify the ZSM-5 molecular sieve to improve the hydrothermal stability, acidity, and catalytic reaction performance of the ZSM-5 molecular sieve, and the like.

[0014] In some specific embodiments, the modified metal element from the first modifier has a weight percentage of 0-5%, such as greater than 0% and less than or equal to 5%, further 0.5%-5%, 0-3%, in terms of oxide of the modified metal element in the modified ZSM-5 molecular sieve. Specifically, the weight percentage of the modified metal element from the first modifier in the modified ZSM-5 molecular sieve can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, and the like specific values and ranges with any two of the above specific values as endpoints.

[0015] In some specific embodiments, the modified ZSM-5 molecular sieve can include 0.2%-25% of titanium, 0.2%-6% of phosphorus, and 0-5% of a modified metal element, in terms of oxide of titanium, phosphorus, and modified metal element, based on 100% of the weight of the modified ZSM-5 molecular sieve.

[0016] In the preparation method of the ZSM-5 molecular sieve, when the first modifier includes a modified metal source, the modified metal source of the first modifier is usually mixed with the titanium source of the first modifier and the raw ZSM-5 molecular sieve, or can be mixed with the titanium source to form an impregnation solution for impregnating the raw ZSM-5 molecular sieve, thereby avoiding precipitation between the phosphorus source and the metal of the first modifier.

[0017] In the above method for preparing ZSM-5 zeolite, the raw ZSM-5 zeolite can have a silica-to-alumina ratio (molar ratio of silicon dioxide to aluminum trioxide) of 15 to 450. In some embodiments, the raw ZSM-5 zeolite can be a ZSM-5 zeolite with a high silica-to-alumina ratio. Specifically, the raw ZSM-5 zeolite can have a silica-to-alumina ratio of 20 to 450, 30 to 450, or the like.

[0018] In the above method for preparing ZSM-5 zeolite, the raw ZSM-5 zeolite can be a micro-mesoporous ZSM-5 zeolite, i.e., a ZSM-5 zeolite containing micropores and mesopores; in some embodiments, the micro-mesoporous ZSM-5 zeolite can have a mesopore volume of no less than 0.10 mL / g, such as 0.10 to 0.70 mL / g, 0.10 to 30 mL / g, 0.30 to 0.70 mL / g, or the like.

[0019] In some embodiments, the raw ZSM-5 zeolite can be added in the form of a slurry, which can be formed by dispersing the raw ZSM-5 zeolite into water.

[0020] In the above method for preparing ZSM-5 zeolite, the pH value of the mixture and / or the impregnation solution can be controlled to be 0.5 to 8, such as 0.5 to 3. By controlling the pH value range, the present application is advantageous in controlling the distribution of titanium in the ZSM-5 zeolite. In some embodiments, the pH value of the mixture and / or the impregnation solution can be 0.5, 1, 1.5, 1.8, 2, 3, 4, 5, 6, 7, 8, or the like, or a range defined by any two of the above values as endpoints.

[0021] According to some embodiments of the present application, the above method for preparing ZSM-5 zeolite can further include an operation of adjusting the pH value of the titanium source in the first modifier to be 0.5 to 8, such as 0.5 to 3, before mixing with the raw ZSM-5 zeolite. Further, when the first modifier includes a modifier metal source, the method can also include an operation of adjusting the pH value of the modifier metal source to be 0.5 to 8, before mixing with the raw ZSM-5 zeolite. By pre-adjusting the pH value of the titanium source and the modifier metal source, it is possible to avoid dealumination of the ZSM-5 zeolite due to excessively high acidity of the system when the titanium source and the modifier metal source are mixed with the ZSM-5 zeolite. Furthermore, by controlling the pH value range, it is possible to regulate the distribution of the modification elements such as titanium in the modified ZSM-5 zeolite.

[0022] In some embodiments, the pH of the mixture, the impregnation solution, the titanium source, and the modified metal source can be adjusted by a pH adjuster, which includes a basic substance. The basic substance can include one or a combination of two or more of ammonia, ammonium carbonate, ammonium bicarbonate, water glass, magnesium oxide, magnesium hydroxide, and magnesium carbonate.

[0023] According to some embodiments of the present application, the method for preparing the modified ZSM-5 molecular sieve can include adjusting the pH of the titanium source and the modified metal source of the first modifier to 0.5-8, filtering, and mixing the filtered filter cake with the raw ZSM-5 molecular sieve.

[0024] In the method for preparing the modified ZSM-5 molecular sieve, the mixture and / or the impregnation solution can further include a dispersant. The dispersant can facilitate the dispersion of the modified metal element and titanium in the molecular sieve, and can be beneficial to improving the hydrothermal stability of the modified ZSM-5 molecular sieve.

[0025] In some embodiments, the dispersant can have a weight of 0-20% of the raw ZSM-5 molecular sieve, such as 0.2-20%, 0-10%, and further controllable to 0.3-6%. In some embodiments, the weight ratio of the dispersant to the raw ZSM-5 molecular sieve can be 0.1%, 0.3%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, and the like, and a range between any two of the above specific values.

[0026] In the method for preparing the modified ZSM-5 molecular sieve, the dispersant can include one or a combination of two or more of 1,3,5-trimethylbenzene, 1,3,5-triisopropylbenzene, methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, and polyethylene glycol.

[0027] In the preparation of the modified ZSM-5 molecular sieve, the dispersant can be added at one time or in several times. Specifically, when the dispersant is added at one time, the dispersant can be added to the mixture and / or the impregnation solution, that is, the dispersant is added together with the titanium source and the modified metal source, which can be beneficial to improving the dispersibility of the titanium element and the modified metal element; alternatively, the dispersant can be added together with the phosphorus source, which can improve the dispersibility of the phosphorus element. When the dispersant is added in several times, part of the dispersant can be added to the mixture containing the titanium source, the modified metal source, and the raw ZSM-5 molecular sieve, or to the impregnation solution containing the titanium source and the modified metal source, and the remaining dispersant can be added together with the phosphorus source, so as to improve the dispersibility of the titanium, the phosphorus, and the modified metal element in the molecular sieve.

[0028] The mixing conditions of the titanium source and the raw ZSM-5 zeolite, and the mixing conditions of the product of the first calcination and the phosphorus source in the above method for preparing the modified ZSM-5 zeolite are not particularly limited, as long as the components are mixed sufficiently. In some embodiments, the mixing temperature of the titanium source and the raw ZSM-5 zeolite can be 4-150°C, and the mixing time can be 10 min-2 h. The mixing temperature of the product of the first calcination and the phosphorus source can be 4-150°C, and the mixing time can be 10 min-2 h.

[0029] In the above method for preparing the modified ZSM-5 zeolite, the temperature of the first calcination can be 450°C-650°C, and the time of the first calcination can be 1 h-4 h. Specifically, the temperature of the first calcination can be 450°C, 500°C, 550°C, 600°C, 650°C, and the like, and ranges having any two of the above specific values as endpoints. The time of the first calcination can be 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, and the like, and ranges having any two of the above specific values as endpoints.

[0030] In the above method for preparing the modified ZSM-5 zeolite, the temperature of the second calcination can be 450°C-650°C, and the time of the second calcination can be 1 h-4 h. Specifically, the temperature of the second calcination can be 450°C, 500°C, 550°C, 600°C, 650°C, and the like, and ranges having any two of the above specific values as endpoints. The time of the second calcination can be 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, and the like, and ranges having any two of the above specific values as endpoints.

[0031] In the above catalytic cracking aid, the aluminum source includes one or a combination of two or more of pseudoboehmite, amorphous alumina, boehmite, aluminum nitrate, and aluminum chloride. In some embodiments, the aluminum source includes pseudoboehmite.

[0032] In the above catalytic cracking aid, the clay can include one or a combination of two or more of kaolin, montmorillonite, diatomite, halloysite (also known as metakaolin), sepiolite, and bentonite. Further, the clay can include one or a combination of two or more of kaolin, diatomite, halloysite, or sepiolite.

[0033] According to embodiments of the present application, the raw material of the catalytic cracking aid includes a second modifier, the second modifier including a phosphorus source, and the catalytic cracking aid contains 5%-20% of phosphorus from the second modifier.

[0034] In the catalytic cracking aid described above, the clay and the aluminum source can synergize with the phosphorus source in the second modifier to improve the adhesion between the components in the aid, thereby improving the wear resistance of the aid.

[0035] In the first modifier and the second modifier described above, the phosphorus source includes one or more than two combinations of phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphoric acid, pyrophosphate, polyphosphoric acid, polyphosphate, metaphosphoric acid, metaphosphate; preferably, the phosphorus source includes one or more than two combinations of phosphoric acid, ammonium phosphate, dihydrogen ammonium phosphate, diammonium hydrogen phosphate, magnesium phosphate, aluminum phosphate, phosphorous acid, ammonium phosphite, sodium pyrophosphate, sodium tripolyphosphate, sodium hexametaphosphate. The phosphorus source used in the first modifier and the second modifier can be the same or different.

[0036] In the catalytic cracking aid described above, the second modifier further includes a titanium source, and the raw material of the catalytic cracking aid further includes titanium from the second modifier, the weight content of the titanium from the second modifier in the raw material of the catalytic cracking aid is 0-10%, for example, greater than 0% and less than or equal to 10%; further can be 0.2%-10%, 0.5%-8% and the like. Specifically, the weight content of the titanium from the second modifier in the raw material of the catalytic cracking aid can be 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10% and the like specific values and the range with any two of the above specific values as the end point.

[0037] According to a specific embodiment of the present application, the weight of the titanium source in the second modifier can be 0%-9.9% of the weight of the raw material of the catalytic cracking aid, for example, greater than 0% and less than 9.9%, in terms of titanium oxide. In some specific embodiments, the weight of the titanium source in the second modifier in the raw material of the catalytic cracking aid can be 0.1%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 9.9% and the like specific values and the range with any two of the above specific values as the end point.

[0038] In the first modifier and the second modifier described above, the titanium source refers to a substance containing titanium element, which can specifically include titanium tetrachloride. Further, the titanium source includes a combination of titanium tetrachloride and hexane; in some specific embodiments, the weight ratio of the titanium tetrachloride and hexane can be (4-34):1, for example, 4:1, 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 34:1 and the like specific values and the range with any two of the above specific values as the end point.

[0039] According to a specific embodiment of the present application, the titanium source in the first modifier and / or the second modifier comprises a titanium tetrachloride-containing waste solution, which contains titanium tetrachloride and further contains hydrocarbons such as n-hexane.

[0040] The titanium tetrachloride-containing waste solution can be a titanium tetrachloride-containing waste solution obtained in the production of a titanium-based polyolefin (e.g., polypropylene) catalyst. The titanium tetrachloride-containing waste solution contains 80%-95% of titanium tetrachloride, 2%-5% of a titanium alkoxy complex, and the balance of hydrocarbons, based on the total weight of the titanium tetrachloride-containing waste solution. The hydrocarbons are liquid at room temperature and contain hexane and esters, with hexane being the major component.

[0041] In the above-described titanium tetrachloride-containing waste solution, the titanium tetrachloride can be used to modify the ZSM-5 molecular sieve; the hexane can promote the uniform distribution of titanium in the ZSM-5 molecular sieve, increase the pore volume of the modified ZSM-5 molecular sieve, and thus improve the diffusion of molecules in the modified ZSM-5 molecular sieve and the selectivity of the modified ZSM-5 molecular sieve in catalytic reactions. Moreover, the hydrocarbons such as hexane present in the titanium tetrachloride-containing solution can form micropores and mesopores after calcination, which is conducive to improving the pore structure of the catalyst and increasing the catalytic activity.

[0042] In some specific embodiments, the titanium tetrachloride-containing waste solution can be generated in the preparation of a titanium-based polypropylene catalyst. The above-described preparation method can solve the problem of waste liquid treatment, save treatment costs, and avoid environmental pollution by using a large amount of titanium tetrachloride-containing waste liquid generated in the preparation of a titanium-based polypropylene catalyst as a raw material.

[0043] The titanium source used in the first modifier and the second modifier can be the same or different.

[0044] In the above-described catalytic cracking aid, the second modifier further comprises a modified metal source, and the raw material of the catalytic cracking aid further comprises a modified metal element from the second modifier. The weight content of the modified metal element from the second modifier in the raw material of the catalytic cracking aid, calculated as the oxide of the modified metal element, is 0-5%, for example, greater than 0% and less than or equal to 5%; further, it can be 0-3%, 0.2%-5%, or 0.5%-3%. Specifically, the weight content of the modified metal in the raw material of the catalytic cracking aid can be 0.1%, 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any value between any two of the above-mentioned specific values.

[0045] In the above first and second modifiers, the modifying metal element can include one or a combination of two or more of iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium. Further, the modifying metal element from the first modifier can include iron and / or zirconium. The modifying element from the second modifier can include one or a combination of two or more of lanthanum, zirconium, and magnesium.

[0046] In the above first and second modifiers, the modifying metal source can specifically include a metal oxide and / or a metal salt. The metal salt as the modifying metal source includes one or a combination of two or more of a chloride, a nitrate, a carbonate, a sulfate, an oxalate, and an acetate. It can be appreciated that the modifying metal element and the modifying metal source employed by the first and second modifiers can be the same or different.

[0047] In the above catalytic cracking aid, the catalytic cracking aid can further include a binder. In some embodiments, the binder includes one or a combination of two or more of an aluminum sol, a silica sol, a silica-alumina sol, and a phosphorous-alumina sol.

[0048] In some embodiments, the weight of the binder, based on the oxide of the binder, can be 0-10%, for example, greater than 0% and less than or equal to 10%, of the weight of the raw material of the catalytic cracking aid; further can be 0-6%. Specifically, the weight of the binder, based on the oxide of the binder, can be 0.1%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, and the like specific values and ranges with any two of the above specific values as the end points.

[0049] In the above catalytic cracking aid, the raw material of the catalytic cracking aid generally includes 15%-55% of the modified ZSM-5 molecular sieve on a dry basis, further can include 20%-50% of the modified ZSM-5 molecular sieve on a dry basis, based on 100% of the weight of the raw material of the catalytic cracking aid. In some embodiments, the weight of the modified ZSM-5 molecular sieve on a dry basis in the raw material of the catalytic cracking aid can be 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, and the like specific values and ranges with any two of the above specific values as the end points.

[0050] In the catalytic cracking aid described above, the raw material of the catalytic cracking aid generally includes 10-55% clay on a dry basis, and further can include 10-50% clay on a dry basis, based on 100% of the weight of the raw material of the catalytic cracking aid. In some specific embodiments, the weight percentage of the clay in the raw material of the catalytic cracking aid can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, and the like specific values and ranges with any two of the above specific values as endpoints, on a dry basis.

[0051] In the catalytic cracking aid described above, the raw material of the catalytic cracking aid generally includes 3-20% aluminum source on a dry basis, and further can include 3-15% aluminum source on a dry basis, based on 100% of the weight of the raw material of the catalytic cracking aid. In some specific embodiments, the weight percentage of the aluminum source in the raw material of the catalytic cracking aid can be 3%, 5%, 10%, 15%, 20%, and the like specific values and ranges with any two of the above specific values as endpoints, on a dry basis.

[0052] In the catalytic cracking aid described above, the raw material of the catalytic cracking aid generally includes 5-20% phosphorus on an oxidant basis, and further can include 6-19% phosphorus on an oxide basis, based on 100% of the weight of the raw material of the catalytic cracking aid. In some specific embodiments, the weight percentage of the phosphorus in the raw material of the catalytic cracking aid can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, and the like specific values and ranges with any two of the above specific values as endpoints, on an oxide basis.

[0053] According to a specific embodiment of the present application, the raw material of the catalytic cracking aid includes 15-55% modified ZSM-5 molecular sieve on a dry basis, 10-55% clay on a dry basis, 3-20% aluminum source (such as pseudo-boehmite) on a dry basis, 5-20% phosphorus (from the second modifier) on an oxide basis, 0-10% binder on an oxide basis, 0-10% titanium (from the second modifier) on an oxide basis, and 0-5% modified metal element (from the second modifier) on an oxide basis, based on 100% of the total weight of the raw material of the catalytic cracking aid.

[0054] According to a specific embodiment of the present application, the raw material of the catalytic cracking aid contains 20%-50% of modified ZSM-5 molecular sieve on a dry basis, 10%-50% of clay on a dry basis, 3%-15% of aluminum source (such as pseudo-boehmite) on a dry basis, 6%-19% of phosphorus (from the second modifier) in terms of oxide, 0-6% of binder in terms of oxide, 0.5%-8% of titanium (from the second modifier) in terms of oxide, and 0-3% of modified metal element (from the second modifier) in terms of oxide, based on 100% of the total weight of the raw material of the catalytic cracking aid.

[0055] According to a specific embodiment of the present application, the titanium contained in the catalytic cracking aid can exist in the form of ions inside and on the surface of the modified ZSM-5 molecular sieve, or in the form of oxide as a carrier in the aid.

[0056] The present application also provides a preparation method of the catalytic cracking aid, which comprises the following steps:

[0057] The modified ZSM-5 molecular sieve, clay and aluminum source are mixed to form a raw material slurry, and the raw material slurry is spray-dried and calcined to obtain the catalytic cracking aid.

[0058] According to a specific embodiment of the present application, the second modifier generally contains a phosphorus source. Further, the second modifier can also contain a titanium source and a modified metal source.

[0059] In the preparation process of the catalytic cracking aid, the content of the modified elements (titanium, phosphorus, etc.) in the catalytic cracking aid can be further increased by introducing the second modifier.

[0060] In the preparation method of the catalytic cracking aid, the modified ZSM-5 molecular sieve can be added in the form of a slurry, and the volume median particle size (D(v, 0.5)) of the slurry of the modified ZSM-5 molecular sieve can be less than or equal to 4 μm (i.e., the particle size of 50% of the volume fraction of particles can be less than or equal to 4 μm). In some specific embodiments, the modified ZSM-5 molecular sieve can be pre-treated by sand milling.

[0061] In the preparation method of the catalytic cracking aid, the volume median particle size D(v, 0.5) of the raw material slurry (formed by the modified ZSM-5 molecular sieve, clay, aluminum source, second modifier, etc.) is less than or equal to 4 μm. The raw material slurry can be treated by sand milling before spray-drying.

[0062] By sand milling the ZSM-5 molecular sieve and the raw material slurry and controlling the particle size, the molecular sieve and other raw materials of the aid can be uniformly dispersed, the wear resistance of the catalytic cracking aid obtained therefrom can be improved, and the reaction performance of the catalytic cracking aid can be improved.

[0063] According to a specific embodiment of the present application, the preparation method further comprises subjecting at least one of the modified ZSM-5 molecular sieve, the clay, and the aluminum source to an acidizing treatment. The acidizing treatment can acidize and disperse the aluminum source such as pseudo-boehmite, gelatinize the aluminum source such as pseudo-boehmite, and have a certain binder effect, thereby improving the attrition resistance of the catalytic cracking aid.

[0064] According to a specific embodiment of the present application, the acid used in the acidizing treatment can comprise an inorganic acid. The inorganic acid can comprise one or a combination of two or more of hydrochloric acid, sulfuric acid, and nitric acid. In some specific embodiments, the weight ratio of the acid to the aluminum source can be controlled to be 0.05-0.3, based on the weight of the aluminum oxide.

[0065] According to a specific embodiment of the present application, the temperature of the acidizing treatment can be 40-90°C, and the time of the acidizing treatment can be 0.5-3h.

[0066] According to a specific embodiment of the present application, the pH value of the titanium source in the second modifier can be 0.5-8. That is, in the preparation of the catalytic cracking aid, the pH value of the titanium source can be adjusted to 0.5-8 first, and then the titanium source can be mixed with the modified ZSM-5 molecular sieve. When the second modifier comprises a modified metal source (especially a modified metal source with higher acidity, such as an iron source, etc.), the pH value of the modified metal source can also be adjusted to 0.5-8 first, and then the modified metal source can be mixed with the modified ZSM-5 molecular sieve.

[0067] In some specific embodiments, the pH value of the titanium source and the modified metal source in the second modifier is adjusted by using an alkaline substance. The alkaline substance can comprise one or a combination of two or more of ammonia, ammonium carbonate, ammonium bicarbonate, water glass, magnesium oxide, magnesium hydroxide, and magnesium carbonate.

[0068] According to a specific embodiment of the present application, the pH value of the titanium source and the modified metal source in the second modifier can be adjusted to 0.5-8 first, and then filtered, and the obtained filter cake can be added to the raw material slurry to be mixed with the modified ZSM-5 molecular sieve.

[0069] According to a specific embodiment of the present application, by adjusting the pH value of the second modifier in advance, the dealumination of the modified ZSM-5 molecular sieve due to the excessively high acidity of the system when the modified ZSM-5 molecular sieve is mixed with the second modifier can be avoided. Moreover, by controlling the pH value range, the distribution of the modified elements such as titanium in the ZSM-5 molecular sieve can be controlled.

[0070] According to a specific embodiment of the present application, the above-mentioned raw material slurry can further include a pore structure modifier. The pore structure modifier can improve the pore structure, specific surface area, and the like of the catalyst. The pore structure modifier can include one or a combination of two or more of 1,3,5-trimethylbenzene, 1,3,5-triisopropylbenzene, methylcellulose, carboxymethylcellulose, polyvinyl alcohol, and polyethylene glycol.

[0071] According to a specific embodiment of the present application, the pore structure modifier can be included in an amount of 0.1% to 10% by weight of the catalytic cracking catalyst raw material, further in an amount of 0.3% to 6%, 0.3% to 5%, and the like. In some specific embodiments, the pore structure modifier can be included in an amount of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, and the like, and ranges having any two of the above-mentioned values as the end points.

[0072] In the above-mentioned method of preparing a catalytic cracking catalyst, the temperature of the calcination and solidification can be 500 to 750°C, further 550 to 570°C, and the time of the calcination and solidification can be 0.5 to 5h, further 1h to 2h. In some specific embodiments, the temperature of the calcination and solidification can be 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 650°C, 700°C, 750°C, and the like, and ranges having any two of the above-mentioned values as the end points. The time of the calcination and solidification can be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, and the like, and ranges having any two of the above-mentioned values as the end points.

[0073] In the above-mentioned method of preparing a catalytic cracking catalyst, the temperature of the calcination and solidification can be 500 to 750°C, further 550 to 570°C, and the time of the calcination and solidification can be 0.5 to 5h, further 1h to 2h. In some specific embodiments, the temperature of the calcination and solidification can be 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 650°C, 700°C, 750°C, and the like, and ranges having any two of the above-mentioned values as the end points. The time of the calcination and solidification can be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, and the like, and ranges having any two of the above-mentioned values as the end points.

[0074] The application also provides application of the above-mentioned catalytic cracking aid in a catalytic cracking process. The above-mentioned catalytic cracking aid provided by the application is convenient to use, does not affect the use performance of the main catalyst, and can achieve use effects when used in a small amount in the main catalyst. The application of the above-mentioned catalytic cracking aid in the catalytic cracking process can reduce the amount of coke formation and promote the production of low-carbon olefins. In some specific embodiments, the reaction temperature of the catalytic cracking process can be 480-530 ℃, and the catalyst-to-oil ratio can be 5-8.

[0075] The beneficial effects of the application include:

[0076] 1. The catalytic cracking aid prepared by using the modified ZSM-5 molecular sieve and used in a heavy oil catalytic cracking process in combination with a catalytic cracking catalyst can promote the conversion of heavy oil in the catalytic cracking process, reduce the yield of heavy oil, increase the total liquid yield (liquefied gas + gasoline + diesel) while increasing the yield of low-carbon olefins such as ethylene and propylene, reduce coke formation, and has excellent cracking reaction selectivity and use performance.

[0077] 2. The catalytic cracking aid provided by the application has a simple and feasible preparation process, and the titanium content can be adjusted in a large range. The performance of the titanium-containing aid of the application is improved: the titanium-containing aid prepared by the application, when used in a heavy oil catalytic cracking process in combination with a catalytic cracking catalyst, can promote the conversion of heavy oil, increase the total liquid yield, reduce coke formation, and has a high yield of low-carbon olefins; the aid is simple and convenient to use, has a small amount, and has a quick effect. Further, the raw material for preparing the aid provided by the application can include waste liquid containing titanium tetrachloride, which not only solves the problem of treatment of the waste liquid and avoids pollution of the environment, but also reduces the high treatment cost of the waste liquid. DETAILED DESCRIPTION

[0078] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the application, the technical solutions of the application will be described in detail below, but it should not be understood as a limitation on the implementable scope of the application.

[0079] In the application, dry basis refers to the state of the material after being calcined at 800 ℃ for 1 h.

[0080] The raw materials used in the examples of the application are as follows:

[0081] (1) Waste liquid containing titanium tetrachloride (hereinafter referred to as waste liquid containing titanium tetrachloride) produced in the preparation process of a titanium-based polypropylene catalyst: the waste liquid contains 90% of titanium (calculated as TiCl4), 2-5% of titanium alkoxide complex, and the balance of hydrocarbons in liquid state at room temperature, with the total weight of the waste liquid being 100%; the hydrocarbons mainly include hexane, and the balance includes esters. The waste liquid is provided by the Lanzhou Chemical Research Center of Petrochemical Research Institute of China Petroleum.

[0082] Kaolin (loss on ignition 29 wt%), halloysite (loss on ignition 16.6 wt%), pseudoboehmite (loss on ignition 36 wt%), alumina sol (alumina content 21.6 wt%), silica sol (silica concentration 30 wt%), ordinary ZSM-5 molecular sieve (silica-alumina ratio 31, mesopore volume 0.04 mL / g): all are industrial products, from the Catalyst Factory of Lanzhou Petrochemical Company.

[0083] LDC-200 catalyst: industrial product, produced by the Catalyst Factory of Lanzhou Petrochemical Company, and treated at 800℃ with 100% steam for 17h.

[0084] (2) Micro-mesoporous ZSM-5 molecular sieve: silica-alumina ratio 30, mesopore volume 0.29 mL / g, purchased, produced in Dalian.

[0085] (3) Diatomite (loss on ignition 2.6 wt%): industrial product, purchased from Inner Mongolia;

[0086] (4) Titanium tetrachloride, magnesium oxide, phosphoric acid (concentration 85%), ammonium dihydrogen phosphate, diammonium hydrogen phosphate, lanthanum oxide, ferric nitrate (Fe(NO3)3·9H2O), zirconium oxide, zirconium sulfate, 1,3,5-trimethylbenzene, polyethylene glycol, carboxymethyl cellulose: all are chemical reagents; n-hexane: analytical reagent.

[0087] (5) Hydrochloric acid: concentration 36%, chemical reagent; nitric acid: concentration 65-68%, chemical reagent; ammonia water: weight concentration 18%, chemical reagent.

[0088] In the following examples and comparative examples, the content of titanium, phosphorus, modified metal and other elements in the modified ZSM-5 molecular sieve is determined by X-ray fluorescence analysis. The crystallinity of ZSM-5 is the relative crystallinity, which is measured by XRD method. The specific surface area retention rate is the ratio of the specific surface area of the modified molecular sieve before aging to the specific surface area after aging multiplied by 100%. The pore volume of the molecular sieve is determined by N2 isothermal adsorption-desorption using a Micromeritics ASAP3000 type automatic physical adsorption instrument.

[0089] In the following examples and comparative examples, the furnace temperature of spray drying is 450℃, and the spray tail gas temperature is 200℃.

[0090] Example 1

[0091] This example provides a catalytic cracking aid, and a preparation method thereof comprises:

[0092] 1. Preparing a modified ZSM-5 molecular sieve:

[0093] (1) 1.402 kg of micro-mesoporous ZSM-5 molecular sieve (dry basis) was added into 4 L of deionized water, stirred uniformly, and then 139 g of waste liquid containing titanium tetrachloride was added, stirred for 0.5 h to form a slurry containing the molecular sieve (as a mixed solution), dried at 120°C, and calcined at 500°C for 1 h; wherein the pH value of the slurry containing the molecular sieve was 1.01;

[0094] (2) The calcined product (molecular sieve) of step (1) was mixed with 4 L of deionized water, 73 g of phosphoric acid was added, stirred uniformly, dried at 120°C, and calcined at 500°C for 1 h to obtain a titanium-phosphorus modified micro-mesoporous ZSM-5 molecular sieve Z-1. According to the calculation of the amount of raw materials added, the composition of the titanium-phosphorus modified micro-mesoporous ZSM-5 molecular sieve was: titanium (as an oxide) 3.5%, phosphorus (as an oxide) 3.0%, and the balance was ZSM-5 molecular sieve.

[0095] 2. Preparation of a catalytic cracking aid:

[0096] 1.08 kg of kaolin (dry basis), 0.36 kg of pseudo-boehmite (dry basis), and 4.05 L of deionized water were added into a beater tank and beaten, stirred for 1 h, then 48 mL of hydrochloric acid was added, stirred for 0.5 h, and then acidified at 50°C for 2 h to obtain an intermediate system;

[0097] Then 1.08 kg of micro-mesoporous ZSM-5 molecular sieve Z-1 (dry basis), 0.799 kg of phosphoric acid, and 30 g of carboxymethyl cellulose were added to the intermediate system, mixed and beaten for 1 h, and then the obtained raw material slurry was subjected to sand milling treatment to make the average particle size D(v, 0.5) of the raw material slurry less than 4 μm, spray dried, and calcined at 550°C for 2 h to obtain a catalytic cracking aid CAT-1.

[0098] The raw material composition of the catalytic cracking aid CAT-1 was: modified micro-mesoporous ZSM-5 molecular sieve Z-1 was 36 wt% (dry basis), kaolin was 36 wt% (dry basis), pseudo-boehmite was 12 wt% (dry basis), and phosphorus pentoxide from the added phosphoric acid in step 2 was 16 wt%.

[0099] Example 2

[0100] This example provides a catalytic cracking aid, and the preparation method thereof comprises:

[0101] 1. Preparation of a modified ZSM-5 molecular sieve:

[0102] (1) 1.388 kg of micro-intermediate pore ZSM-5 molecular sieve (dry basis), 15 g of polyethylene glycol were added into 3.5 L of deionized water, stirred uniformly, then 20 g of waste liquid containing titanium tetrachloride, 103 g of zirconium sulfate were added, stirred for 1.5 h to form a slurry containing molecular sieve, dried at 100°C, and calcined at 550°C for 1.5 h; wherein the pH value of the slurry containing molecular sieve was 1.52;

[0103] (2) The molecular sieve calcined in step (1) was mixed with 15 g of polyethylene glycol and 3.5 L of deionized water, 97 g of phosphoric acid was added, stirred uniformly, dried at 100°C, and calcined at 550°C for 1.5 h to obtain a titanium-zirconium-phosphorus modified micro-intermediate pore ZSM-5 molecular sieve Z-2. According to the amount of raw materials added, the composition of the titanium-zirconium-phosphorus modified micro-intermediate pore ZSM-5 molecular sieve was: titanium (as oxide) 0.5%, phosphorus (as oxide) 4.0%, zirconium (as oxide) 3.0%, and the balance was ZSM-5 molecular sieve.

[0104] 2. Preparation of catalytic cracking aid:

[0105] 1.14 kg of kaolin (dry basis), 0.12 kg of pseudo-boehmite (dry basis) were added into a beater tank and beaten with 4.18 L of deionized water, stirred for 0.5 h, then 12.1 mL of hydrochloric acid was added, stirred for 15 min, and then acidified at 50°C for 1 h to obtain an intermediate system;

[0106] Then 0.972 kg of aluminum sol, 1.14 kg of titanium-zirconium-phosphorus modified micro-intermediate pore ZSM-5 molecular sieve Z-2 (dry basis), 30 g of lanthanum oxide, 0.585 kg of phosphoric acid, and 15 g of polyethylene glycol were added to the intermediate system, and the obtained raw material slurry was beaten for 0.5 h, then the average particle size D(v, 0.5) of the raw material slurry was less than 4 μm after sand milling treatment, spray drying, and calcination at 500°C for 1 h to obtain a catalytic cracking aid CAT-2.

[0107] The raw material composition of the catalytic cracking aid CAT-2 was: modified micro-intermediate pore ZSM-5 molecular sieve Z-2 was 38 wt% (dry basis), kaolin was 38 wt% (dry basis), pseudo-boehmite was 4 wt% (dry basis), aluminum oxide from aluminum sol was 7 wt%, lanthanum oxide was 1 wt%, and phosphorus pentoxide from the added phosphoric acid in step 2 was 12 wt%.

[0108] Example 3

[0109] The present embodiment provides a catalytic cracking aid, and a preparation method thereof, which comprises:

[0110] 1. Preparation of modified ZSM-5 molecular sieve:

[0111] (1) Under stirring, 792 g of waste liquid containing titanium tetrachloride, 113.6 g of ferric nitrate, and 110 g of carboxymethyl cellulose were added into 3.6 L of deionized water, stirred for 10 min, and then the pH value was adjusted to 6.51 by using ammonia water. Then, 1.102 kg of ordinary ZSM-5 molecular sieve (dry basis) was added and stirred for 1 h to form a slurry containing the molecular sieve. The slurry was dried at 100°C and calcined at 520°C for 1 h. The pH value of the slurry containing the molecular sieve was 5.66.

[0112] (2) The calcined molecular sieve of step (1), 110 g of carboxymethyl cellulose, and 3.6 L of deionized water were mixed, and 139 g of diammonium hydrogen phosphate was added and stirred uniformly. The mixture was dried at 100°C and calcined at 520°C for 1 h to obtain a titanium-iron-phosphorus modified ZSM-5 molecular sieve Z-3. According to the calculation of the amount of raw materials added, the composition of the titanium-iron-phosphorus modified ZSM-5 molecular sieve was: titanium (as oxide) 20.0%, phosphorus (as oxide) 5.0%, iron (as oxide) 1.5%, and the balance being ZSM-5 molecular sieve.

[0113] 2. Preparation of a catalytic cracking aid:

[0114] 1.5 kg of ZSM-5 molecular sieve Z-3 (dry basis) was added into 4 L of deionized water and stirred, and then sand milling was performed to make the average particle size D(v, 0.5) of the molecular sieve Z-3 slurry less than 4 μm.

[0115] The molecular sieve Z-3 slurry with an average particle size D(v, 0.5) less than 4 μm, 0.93 kg of halloysite (dry basis), 0.18 kg of pseudo-boehmite (dry basis), and 0.7 L of deionized water were added into a beater tank and beaten, stirred for 2 h, and then 22.7 mL of hydrochloric acid was added. After stirring for 25 min, the mixture was acidified at 70°C for 1 h, and then cooled to 35°C to obtain an intermediate system.

[0116] Then, 694 g of aluminum sol, 0.390 kg of phosphoric acid, and 150 g of carboxymethyl cellulose were added into the intermediate system, and the mixture was beaten for 0.5 h. The raw material slurry was then homogenized, spray dried, and calcined at 600°C for 3 h to obtain a catalytic cracking aid CAT-3.

[0117] The raw material composition of the catalytic cracking aid CAT-3 was: modified ZSM-5 molecular sieve Z-3 50 wt% (dry basis), halloysite 31 wt% (dry basis), pseudo-boehmite 6 wt% (dry basis), aluminum oxide from the aluminum sol 5 wt%, and phosphorus pentoxide from the added phosphoric acid in step 2 8 wt%.

[0118] Example 4

[0119] The present embodiment provides a catalytic cracking aid, and a preparation method thereof, which comprises the following steps:

[0120] 1. Preparation of modified ZSM-5 molecular sieve: Titanium-phosphorus modified ZSM-5 molecular sieve Z-1 was prepared according to the method of preparing modified ZSM-5 molecular sieve in Example 1.

[0121] 2. Preparation of catalytic cracking aid:

[0122] 0.96 kg of titanium-phosphorus modified ZSM-5 molecular sieve Z-1 prepared in step 1 (dry basis) was added to 2.2 L of deionized water, stirred, and sand-milled to make the average particle size D(v, 0.5) of the molecular sieve Z-1 slurry less than 4 μm.

[0123] 30 g of magnesium oxide was added to 1.8 L of deionized water, stirred, and 475 g of titanium tetrachloride-containing waste liquid was added, and the pH value was adjusted to 7 with ammonia water, and then filtered to obtain a titanium-magnesium-containing filter cake A.

[0124] 1.065 kg of kaolin (dry basis), 0.24 kg of pseudo-boehmite (dry basis), and 1.5 L of deionized water were added to a beater tank and beaten, stirred for 40 min, then 28.2 mL of hydrochloric acid was added, stirred for 15 min, and then acidified at 45°C for 1.5 h to obtain an intermediate system.

[0125] 600 g of silica sol, the above-mentioned molecular sieve Z-1 slurry with an average particle size D(v, 0.5) less than 4 μm, filter cake A, 0.487 kg of phosphoric acid, 45 g of zirconium oxide, and 9 g of 1,3,5-trimethylbenzene were further added to the intermediate system, mixed and beaten for 1 h, and then the obtained raw material slurry was homogenized, spray-dried, and calcined at 570°C for 1.5 h to obtain a catalytic cracking aid CAT-4.

[0126] The raw material composition of the catalytic cracking aid CAT-4 was: modified micro-mesoporous ZSM-5 molecular sieve Z-1 was 32 wt% (dry basis), kaolin was 35.5 wt% (dry basis), pseudo-boehmite was 8 wt% (dry basis), silicon oxide from silica sol was 6 wt%, zirconium oxide was 1.5 wt%, titanium from filter cake A was 6 wt% (calculated as oxide), magnesium from filter cake A was 1 wt% (calculated as oxide), and phosphorus pentoxide from phosphoric acid added in step 2 was 10 wt%.

[0127] Example 5

[0128] This example provides a catalytic cracking aid, and the preparation method thereof comprises:

[0129] 1. Preparation of modified ZSM-5 molecular sieve:

[0130] (1) Take 170.6 g of Fe(NO3)3·9H2O and 107 g of waste liquid containing titanium tetrachloride, dissolve them in an appropriate amount of distilled water to prepare a mixed iron nitrate / titanium tetrachloride impregnation solution, and the pH value of the mixed iron nitrate / titanium tetrachloride impregnation solution is 0.56; slowly pour the mixed impregnation solution into 1.381 kg of ordinary ZSM-5 molecular sieve (dry basis), continuously stir to achieve equal volume impregnation; after standing for 12 h, dry in a 120°C oven for 6 h; calcine in a 540°C muffle furnace for 4 h to obtain modified molecular sieve Fe-Ti / ZSM-5;

[0131] (2) Mix the modified molecular sieve Fe-Ti / ZSM-5 from step (1) with 3.6 L of deionized water, add 73 g of ammonium dihydrogen phosphate, stir until uniform, dry at 120°C, and calcine at 520°C for 1 h to obtain titanium-iron-phosphorus modified ZSM-5 molecular sieve Z-4. According to the calculation of the amount of raw materials added, the composition of the titanium-iron-phosphorus modified ZSM-5 molecular sieve is: titanium (as oxide) 2.7%, phosphorus (as oxide) 3.0%, iron (as oxide) 2.25%, and the balance is ZSM-5 molecular sieve.

[0132] 2. Preparation of catalytic cracking aid:

[0133] Put 0.78 kg of kaolin (dry basis), 0.18 kg of diatomite (dry basis), 0.3 kg of pseudo-boehmite (dry basis), and 4.18 L of deionized water into a beater tank and beat, stir for 0.5 h, then add 25 mL of nitric acid, stir for 45 min, and then acidify at 55°C for 2 h to obtain an intermediate system;

[0134] Add 1.26 kg of ZSM-5 molecular sieve Z-4 (dry basis), 0.799 kg of phosphoric acid, and 30 g of polyethylene glycol to the intermediate system, mix and beat for 1 h, then subject the obtained raw material slurry to sand milling treatment to make the average particle size D(v,0.5) of the raw material slurry less than 4 μm, spray dry, and calcine at 500°C for 2 h to obtain a catalytic cracking aid CAT-5.

[0135] The raw material composition of the catalytic cracking aid CAT-5 is: modified ZSM-5 molecular sieve Z-4 42 wt% (dry basis), kaolin 26 wt% (dry basis), diatomite 6 wt% (dry basis), pseudo-boehmite 10 wt% (dry basis), and phosphorus pentoxide from the added phosphoric acid in step 2 16 wt%.

[0136] Example 6

[0137] This example provides a catalytic cracking aid, and the preparation method thereof comprises:

[0138] 1. Preparation of modified ZSM-5 molecular sieve:

[0139] (1) 1.402 kg of micro-mesoporous ZSM-5 molecular sieve (dry basis) was added into 4 L of deionized water, stirred uniformly, then 125 g of titanium tetrachloride was added, stirred for 0.5 h, to form a slurry containing the molecular sieve (as a mixed solution), dried at 120°C, and calcined at 500°C for 1 h; wherein the pH value of the slurry containing the molecular sieve was 1.03;

[0140] (2) The calcined product of step (1) was mixed with 4 L of deionized water, 73 g of phosphoric acid was added, stirred uniformly, dried at 120°C, and calcined at 500°C for 1 h to obtain a titanium-phosphorus modified micro-mesoporous ZSM-5 molecular sieve, denoted as Z-5.

[0141] According to the calculation of the amount of raw materials added, the composition of the titanium-phosphorus modified micro-mesoporous ZSM-5 molecular sieve was: titanium (as an oxide) 3.5%, phosphorus (as an oxide) 3.0%, and the balance was ZSM-5 molecular sieve.

[0142] 2. Preparation of a catalytic cracking aid:

[0143] 1.08 kg of kaolin (dry basis), 0.36 kg of pseudo-boehmite (dry basis), and 4.05 L of deionized water were added into a beater tank for beating, stirred for 1 h, then 48 mL of hydrochloric acid was added, stirred for 0.5 h, and then acidified at 50°C for 2 h to obtain an intermediate system;

[0144] Then, 1.08 kg of micro-mesoporous ZSM-5 molecular sieve Z-5 (dry basis), 0.799 kg of phosphoric acid, and 30 g of carboxymethyl cellulose were added to the intermediate system, mixed and beaten for 1 h, then the obtained raw material slurry was subjected to sand milling treatment to make the average particle size D(v, 0.5) of the raw material slurry less than 4 μm, spray dried, and calcined at 550°C for 2 h to obtain a catalytic cracking aid CAT-6.

[0145] The raw material composition of the catalytic cracking aid CAT-6 was: modified micro-mesoporous ZSM-5 molecular sieve Z-5 was 36 wt% (dry basis), kaolin was 36 wt% (dry basis), pseudo-boehmite was 12 wt% (dry basis), and phosphorus pentoxide from the added phosphoric acid in step 2 was 16 wt%.

[0146] Example 7

[0147] The present embodiment provides a catalytic cracking aid, and a preparation method thereof, which comprises:

[0148] 1. Preparation of a modified ZSM-5 molecular sieve:

[0149] (1) Under stirring, 712 g of titanium tetrachloride, 113.6 g of ferric nitrate, 21 g of n-hexane, 110 g of carboxymethyl cellulose were added into 3.6 L of deionized water, stirred for 10 min, the pH value was adjusted to 6.51 with ammonia water, then 1.102 kg of ordinary ZSM-5 molecular sieve (dry basis) was added, stirred for 1 h to form a slurry containing the molecular sieve, dried at 100 ℃, and calcined at 520 ℃ for 1 h; wherein the pH value of the slurry containing the molecular sieve was 5.70;

[0150] (2) The calcined product of step (1), 110 g of carboxymethyl cellulose and 3.6 L of deionized water were mixed, then 139 g of diammonium hydrogen phosphate was added, stirred uniformly, dried at 100 ℃, and calcined at 520 ℃ for 1 h to obtain a titanium-iron-phosphorus modified ZSM-5 molecular sieve, which is denoted as Z-6. According to the calculation of the amount of raw materials added, the titanium-iron-phosphorus modified ZSM-5 molecular sieve contains 20.0% of titanium (calculated as oxide), 1.5% of iron (calculated as oxide), and 5.0% of phosphorus (calculated as oxide).

[0151] 2. Preparation of catalytic cracking aid:

[0152] 1.5 kg of ZSM-5 molecular sieve Z-6 (dry basis) was added into 4 L of deionized water and stirred, and sand milling treatment was performed to make the average particle size D(v, 0.5) of the molecular sieve Z-6 slurry less than 4 μm.

[0153] The molecular sieve Z-6 slurry with an average particle size D(v, 0.5) less than 4 μm, 0.93 kg of halloysite (dry basis), 0.18 kg of pseudo-boehmite (dry basis), and 0.7 L of deionized water were added into a beater tank for beating, stirred for 2 h, then 22.7 mL of hydrochloric acid was added, stirred for 25 min, and then aged at 70 ℃ for 1 h, and cooled to 35 ℃ to obtain an intermediate system.

[0154] 694 g of aluminum sol, 0.390 kg of phosphoric acid, and 150 g of carboxymethyl cellulose were further added into the intermediate system, mixed and beaten for 0.5 h, then the obtained raw material slurry was subjected to homogenization, spray drying, and calcination at 600 ℃ for 3 h to obtain a catalytic cracking aid CAT-7.

[0155] The composition of the catalytic cracking aid CAT-7 is as follows: the modified ZSM-5 molecular sieve Z-6 is 50 wt% (dry basis), the halloysite is 31 wt% (dry basis), the pseudo-boehmite is 6 wt% (dry basis), the aluminum oxide from the aluminum sol is 5 wt%, and the phosphorus pentoxide from the added phosphoric acid in step 2 is 8 wt%.

[0156] Comparative Example 1

[0157] This comparative example provides a catalytic cracking aid, and the preparation method thereof comprises:

[0158] 1. Preparation of modified ZSM-5 molecular sieve:

[0159] (1) 1.455 kg of micro-mesoporous ZSM-5 molecular sieve (dry basis) was added into 4 L of deionized water, stirred for 0.5 h to form a slurry containing the molecular sieve, dried at 120 °C, and calcined at 500 °C for 1 h; wherein the pH value of the slurry containing the molecular sieve was 2.51;

[0160] (2) The calcined molecular sieve of step (1) was mixed with 4 L of deionized water, 73 g of phosphoric acid was added, stirred uniformly, dried at 120 °C, and calcined at 500 °C for 1 h to obtain a phosphorus-modified micro-mesoporous ZSM-5 molecular sieve DZ-1. According to the calculation of the amount of raw materials added, the composition of the phosphorus-modified micro-mesoporous ZSM-5 molecular sieve was: phosphorus (as an oxide) 3.0%, and the balance was ZSM-5 molecular sieve.

[0161] 2. Preparation of catalytic cracking additive:

[0162] 1.08 kg of kaolin (dry basis), 0.36 kg of pseudo-boehmite (dry basis), and 4.05 L of deionized water were added into a beater to beat, stirred for 1 h, then 48 mL of hydrochloric acid was added, stirred for 0.5 h, and then acidified at 50 °C for 2 h to obtain an intermediate system;

[0163] Then 1.08 kg of micro-mesoporous ZSM-5 molecular sieve DZ-1 (dry basis), 30 g of carboxymethyl cellulose, and 0.799 kg of phosphoric acid were added to the intermediate system, mixed and beaten for 1 h, then homogenized, spray dried, and calcined at 550 °C for 2 h to obtain a catalytic cracking additive DCAT-1.

[0164] The composition of the catalytic cracking additive DCAT-1 was: modified micro-mesoporous ZSM-5 molecular sieve DZ-1 was 36 wt% (dry basis), kaolin was 36 wt% (dry basis), pseudo-boehmite was 12 wt% (dry basis), and phosphorus pentoxide from the added phosphoric acid in step 2 was 16 wt%.

[0165] Comparative Example 2

[0166] This comparative example provides a catalytic cracking additive, and the preparation method thereof comprises:

[0167] 1. Preparation of modified ZSM-5 molecular sieve:

[0168] (1) 1.455 kg of ordinary ZSM-5 molecular sieve (dry basis) was added into 4 L of deionized water, stirred for 0.5 h to form a slurry containing the molecular sieve, dried at 120 °C, and calcined at 500 °C for 1 h; wherein the pH value of the slurry containing the molecular sieve was 2.53;

[0169] (2) The ZSM-5 molecular sieve after calcination in step (1) is mixed with 4 L of deionized water, 73 g of phosphoric acid is added, stirred uniformly, dried at 120°C, and calcined at 500°C for 1 h to obtain a phosphorus-modified ZSM-5 molecular sieve DZ-2. According to the calculation of the amount of raw materials added, the composition of the phosphorus-modified ZSM-5 molecular sieve is: phosphorus (calculated as an oxide) 3.0%, and the balance is ZSM-5 molecular sieve.

[0170] 2. Preparation of a catalytic cracking aid:

[0171] 1.08 kg of kaolin (dry basis), 0.36 kg of pseudoboehmite (dry basis), and 4.05 L of deionized water are added to a beater tank for beating, stirred for 1 h, then 48 mL of hydrochloric acid is added, stirred for 0.5 h, and then acidified at 50°C for 2 h to obtain an intermediate system;

[0172] Then 1.08 kg of ZSM-5 molecular sieve DZ-2 (dry basis), 30 g of carboxymethyl cellulose, and 0.799 kg of phosphoric acid are added, mixed and beaten for 1 h, then homogenized, spray dried, and calcined at 550°C for 2 h to obtain a comparative aid DCAT-2.

[0173] The composition of the catalytic cracking aid DCAT-2 is: modified ZSM-5 molecular sieve DZ-2 36 wt% (dry basis), kaolin 36 wt% (dry basis), pseudoboehmite 12 wt% (dry basis), and phosphorus pentoxide from the added phosphoric acid in step 2 16 wt%.

[0174] Comparative Example 3

[0175] This comparative example provides a catalytic cracking aid, and the preparation method thereof comprises:

[0176] 1. Preparation of a modified ZSM-5 molecular sieve:

[0177] 170.6 g of Fe(NO3)3·9H2O and 96 g of titanium tetrachloride are dissolved in an appropriate volume of distilled water to prepare a mixed iron nitrate / titanium tetrachloride impregnation solution, which is slowly poured into 1.426 kg of ordinary ZSM-5 molecular sieve (dry basis) while stirring to achieve equal-volume impregnation; after standing for 12 h, it is placed in a 120°C oven for drying for 6 h; and then calcined in a 540°C muffle furnace for 4 h to obtain a modified ZSM-5 molecular sieve DZ-3. According to the calculation of the amount of raw materials added, the composition of the titanium-modified ZSM-5 molecular sieve is: titanium (calculated as an oxide) 2.7%, iron (calculated as an oxide) 2.25%, and the balance is ZSM-5 molecular sieve.

[0178] 2. Preparation of a catalytic cracking aid:

[0179] Into a beater tank, 0.78 kg of kaolin (dry basis), 0.18 kg of diatomite (dry basis), 0.3 kg of pseudo-boehmite (dry basis) and 4.18 L of deionized water were beaten, stirred for 0.5 h, then 25 mL of nitric acid was added, stirred for 45 min, and acidified at 55 °C for 2 h to obtain an intermediate system;

[0180] Then 1.26 kg of modified ZSM-5 molecular sieve DZ-3 (dry basis), 30 g of polyethylene glycol, and 0.799 kg of phosphoric acid were added, mixed and beaten for 1 h, then homogenized, spray dried, and calcined at 500 °C for 2 h to obtain a comparative catalyst DCAT-3.

[0181] The composition of the catalytic cracking catalyst DCAT-3 is: modified ZSM-5 molecular sieve DZ-3 is 42 wt% (dry basis), kaolin is 26 wt% (dry basis), diatomite is 6 wt% (dry basis), pseudo-boehmite is 10 wt% (dry basis), and phosphorus pentoxide from the added phosphoric acid in step 2 is 16 wt%.

[0182] Comparative Example 4

[0183] This comparative example provides a catalytic cracking catalyst, and the preparation method thereof comprises:

[0184] 1. Preparation of modified ZSM-5 molecular sieve:

[0185] (1) 1.402 kg of micro-mesoporous ZSM-5 molecular sieve (dry basis) was added to 4 L of deionized water, stirred uniformly, then 73 g of phosphoric acid was added, stirred uniformly, dried at 120 °C, and calcined at 500 °C for 1 h;

[0186] (2) The calcined product of step (1) was mixed with 4 L of deionized water, 139 g of waste liquid containing titanium tetrachloride was added, stirred for 0.5 h to form a slurry containing molecular sieve, stirred uniformly, dried at 120 °C, and calcined at 500 °C for 1 h to obtain phosphorus-titanium modified micro-mesoporous ZSM-5 molecular sieve, denoted as DZ-4.

[0187] According to the calculation of the amount of raw materials added, the composition of the phosphorus-titanium modified micro-mesoporous ZSM-5 molecular sieve is: titanium (as oxide) 3.5%, phosphorus (as oxide) 3.0%, and the balance is ZSM-5 molecular sieve.

[0188] 2. Preparation of catalytic cracking catalyst:

[0189] Into a beater tank, 1.08 kg of kaolin (dry basis), 0.36 kg of pseudo-boehmite (dry basis) and 4.05 L of deionized water were beaten, stirred for 1 h, then 48 mL of hydrochloric acid was added, stirred for 0.5 h, and acidified at 50 °C for 2 h to obtain an intermediate system;

[0190] To the intermediate system, 1.08 kg of micro-intermediate pore ZSM-5 zeolite DZ-4 (dry basis), 0.799 kg of phosphoric acid, 30 g of carboxymethyl cellulose were added, and mixed and beaten for 1 h. The obtained raw material slurry was subjected to sand milling treatment to make the average particle size D(v, 0.5) of the raw material slurry less than 4 μm, and then was spray dried and calcined at 550 ℃ for 2 h to obtain a comparative catalyst DCAT-4.

[0191] The raw material composition of the catalytic cracking catalyst DCAT-4 was as follows: modified micro-intermediate pore ZSM-5 zeolite DZ-4 was 36 wt% (dry basis), kaolin was 36 wt% (dry basis), pseudo-boehmite was 12 wt% (dry basis), and the phosphorus pentoxide from the added phosphoric acid in step 2 was 16 wt%.

[0192] The median particle size of the catalysts obtained in the above examples and comparative examples was 65-78 μm.

[0193] Test Example 1

[0194] (1) The test results of the hydrothermal stability of the modified ZSM-5 zeolites prepared in the above examples and comparative examples were provided.

[0195] The modified ZSM-5 zeolites Z-1, Z-2, Z-3, Z-4, etc. prepared in Examples 1-3 and 5-7 and the modified ZSM-5 zeolites DZ-1, DZ-2, DZ-3, DZ-4 prepared in Comparative Examples 1-4 were respectively taken as the samples to be tested, and the specific surface area of each sample to be tested was measured. Then, each sample to be tested was aged at 800 ℃ under 100% water vapor for 17 h, and the specific surface area of the aged sample to be tested was measured, and the specific surface area retention rate was calculated. The results are shown in Table 1.

[0196] Table 1: Test results of the specific surface area retention rate of the ZSM-5 zeolites in Examples 1-3 and 5-7 and Comparative Examples 1-4

[0197]

[0198] The results in Table 1 show that, after being aged at 800 ℃ under 100% water vapor for 17 h, the specific surface area retention rate of the ZSM-5 zeolite prepared by the method of the present application is higher than that of the comparative ZSM-5 zeolites DZ-1, DZ-2, DZ-3, DZ-4 prepared in the comparative examples.

[0199] In the examples, the difference between Example 1 and Comparative Example 1 is only whether a titanium source is added. The specific surface area retention rate of the titanium-phosphorus modified ZSM-5 zeolite in Example 1 is 11.7% higher than that of the phosphorus modified ZSM-5 zeolite in Comparative Example 1.

[0200] The difference between Comparative Example 4 and each of the examples (especially Example 6) is the modification sequence of the phosphorus source and the titanium source. As can be seen from Table 1, compared with modifying the ZSM-5 molecular sieve with phosphorus first and then modifying the ZSM-5 molecular sieve with titanium, the reaction sequence of modifying the ZSM-5 molecular sieve with titanium first and then modifying the ZSM-5 molecular sieve with phosphorus used in the present application can obviously improve the specific surface area retention rate of the molecular sieve, and the improvement can reach more than 8 percentage points. The above results show that by controlling the reaction sequence, the hydrothermal stability of the ZSM-5 molecular sieve can be effectively improved.

[0201] Example 5 and Comparative Example 3 use different modified elements. As can be seen by comparison, the specific surface area retention rate of the titanium-iron-phosphorus modified ZSM-5 molecular sieve of Example 5 is 10.4% higher than the specific surface area retention rate of the titanium-iron modified ZSM-5 molecular sieve of Comparative Example 3.

[0202] Example 1 and Example 6 use different types of titanium sources. As can be seen from Table 1, modifying the molecular sieve with pure titanium tetrachloride or waste liquid containing titanium tetrachloride as the titanium source can improve the specific surface area retention rate of the molecular sieve to a certain extent; among them, using waste liquid containing titanium tetrachloride as the titanium source has a more obvious effect of improving the hydrothermal stability.

[0203] The above results show that the preparation method of the present application can obviously improve the hydrothermal stability of the titanium-phosphorus modified ZSM-5 molecular sieve obtained thereby by using titanium and phosphorus as the modified elements and controlling the reaction sequence; on this basis, using iron, zirconium, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium as the second metal for modification can further improve the performance of the ZSM-5 molecular sieve.

[0204] (2) The test example also provides the analysis results of the element composition of the modified ZSM-5 molecular sieves of the above examples and comparative examples. The content of each element in the samples of the above examples and comparative examples is tested by X-ray fluorescence analysis method, the weight content of titanium, phosphorus, iron, and zirconium is calculated as oxide, and the weight content of chlorine is calculated as Cl element, and the test results are summarized in Table 2.

[0205] Table 2 Analysis results of the element content of the modified ZSM-5 molecular sieves of Examples 1-3, 5-7, and Comparative Examples 1-4

[0206]

[0207] The main difference between Comparative Example 4 and each of the examples (especially Example 1) is that in Comparative Example 4, the ZSM-5 molecular sieve is first modified with phosphorus and then modified with titanium, while in the examples, the ZSM-5 molecular sieve is first modified with titanium and then modified with phosphorus. The results show that the Cl content in the modified ZSM-5 molecular sieve of each of the examples is close to 0, while the Cl content in the modified ZSM-5 molecular sieve of Comparative Example 4 is more than 7%, indicating that the modified ZSM-5 molecular sieve prepared in the examples of the application contains less impurities, and further indicating that the reaction sequence of the application can effectively reduce the impurity content in the modified ZSM-5 molecular sieve and improve the quality of the molecular sieve. In the process of catalytic cracking reaction, if the chlorine content on the molecular sieve and catalyst is too high, it is easy to cause corrosion and salt deposition of the catalytic cracking device, which is not conducive to the long-term stable operation of the device.

[0208] The appearance color of the modified ZSM-5 molecular sieve (first titanium modification, then phosphorus modification) of each of the examples is white, while the appearance color of the modified ZSM-5 molecular sieve (first phosphorus modification, then titanium modification) of Comparative Example 4 is gray. This result indicates that the template in the modified ZSM-5 molecular sieve of Comparative Example 4 is not easy to remove, while the template can block the molecular sieve channels, which has an adverse effect on the catalytic process; while the template in the modified ZSM-5 molecular sieve prepared by the application is easy to remove by the calcination process, thereby avoiding the situation that the template blocks the molecular sieve channels, which is conducive to improving the selectivity of the molecular sieve in the catalytic reaction. The results of the pore volume determination also show that the pore volume of the modified ZSM-5 molecular sieve prepared in Comparative Example 4 is 0.25 mL / g, and the pore volume of the modified ZSM-5 molecular sieve prepared in Example 1 is 0.31 mL / g, indicating that the modified ZSM-5 molecular sieve prepared by the application has a relatively unobstructed channel structure.

[0209] The crystallinity of the modified ZSM-5 molecular sieves of Example 1, Example 2, Example 6, Comparative Example 1 and Comparative Example 4 was analyzed, and the results of the crystallinity of each molecular sieve were as follows: the crystallinity of the molecular sieve of Example 1 was 65%, the crystallinity of the molecular sieve of Example 2 was 66%, the crystallinity of the molecular sieve of Example 6 was 65%, the crystallinity of the molecular sieve of Comparative Example 1 was 60%, and the crystallinity of the molecular sieve of Comparative Example 4 was 63%. The main difference between Comparative Example 1 and Examples 1 and 2 was that Comparative Example 1 only used phosphorus-modified ZSM-5 molecular sieves and did not use titanium modification. During the modification of the molecular sieves, high-temperature calcination treatment was performed, which caused dealumination and structural damage to the molecular sieves during the calcination process, resulting in a decrease in the crystallinity of the molecular sieves measured by XRD. Therefore, the crystallinity of the molecular sieves in the modified product can reflect the stability of the molecular sieves. Compared with the modified ZSM-5 molecular sieves prepared in Comparative Example 1, the crystallinity of the ZSM-5 molecular sieves in the modified ZSM-5 molecular sieves of Examples 1, 2 and 6 was increased by more than 5 percentage points, indicating that the titanium-phosphorus synergistic modification made the modified ZSM-5 molecular sieves prepared in the present application more stable than the modified ZSM-5 molecular sieves of Comparative Example 1. Compared with the modified ZSM-5 molecular sieves of Comparative Example 4, the crystallinity of the ZSM-5 molecular sieves in the modified ZSM-5 molecular sieves of Example 1 was increased by 2 percentage points, while the crystallinity of the ZSM-5 molecular sieves in the modified ZSM-5 molecular sieves of Comparative Example 4 was lower, at 63%, which also indicates that the modified ZSM-5 molecular sieves prepared in the present application are more stable than the modified ZSM-5 molecular sieves of Comparative Example 4. The above results show that the stability of the ZSM-5 molecular sieves can be effectively improved by titanium-phosphorus synergistic modification (further modification with modification metals such as zirconium) and control of the modification sequence.

[0210] Test Example 2

[0211] This test example was used to evaluate the performance of the catalytic cracking aids of the above examples and comparative examples.

[0212] The catalytic cracking aids CAT-1, CAT-2, CAT-3 and CAT-4 prepared in Examples 1 to 4 and the comparative aids DCAT-1 and DCAT-2 of Comparative Examples 1 and 2 were used as the samples to be tested, an industrial catalyst with the trade name LDC-200 was mixed with each sample to be tested at a weight ratio of 9:1 to obtain six groups of catalyst mixtures, and the six groups of catalyst mixtures were aged at 800°C under 100% steam for 17 hours, and then the catalytic cracking reaction performance of each catalyst mixture was evaluated on a heavy oil micro-reaction evaluation device (ACE).

[0213] The results of the catalytic cracking reaction selectivity evaluation of the catalytic cracking aids of the above examples and comparative examples are shown in Table 3.

[0214] In Table 3, total liquid yield = liquefied gas yield + gasoline yield + diesel yield; coke factor = (100 - conversion rate) x coke yield / conversion rate.

[0215] Table 3

[0216]

[0217] The results in Table 3 show that, compared with the comparative aids DCAT-1 and DCAT-2 of Comparative Examples 1 and 2, when the catalytic cracking aids CAT-1, CAT-2, CAT-3 and CAT-4 of the application are added to the LDC-200 industrial catalyst, the conversion rate of catalytic cracking reaction is increased, the heavy oil yield is reduced, the coke factor is reduced, the total liquid yield is increased, and the low-carbon olefin (ethylene + propylene + butene) yield is increased. Among them, the conversion rate of catalytic cracking reaction of Example 1 is increased by 1.33% compared with Comparative Example 2, the total liquid yield is increased by 1.31%, the coke yield is reduced by 0.51%, the coke factor is reduced, the low-carbon olefin (ethylene + propylene + butene) yield is increased by 2.06%, and it has the characteristics of excellent heavy oil conversion, reduced coking and prolific low-carbon olefin. It shows that the use of the aid provided by the application can promote the efficient conversion of heavy oil, reduce the coking tendency, and at the same time, prolific low-carbon olefin, and improve the selectivity of catalytic cracking reaction.

[0218] Test Example 3

[0219] This test example is used to evaluate the performance of the catalytic cracking aids of Example 5 and Comparative Example 3.

[0220] The catalytic cracking aid CAT-5 prepared in Example 5 and the comparative aid DCAT-3 of Comparative Example 3 are used as the test samples, the LDC-200 industrial catalyst is mixed with the test samples in a weight ratio of 9:1 to obtain two groups of catalyst mixtures, and the two groups of catalyst mixtures are respectively aged at 800℃ and 100% steam for 17h, and then the catalytic cracking reaction performance evaluation is carried out on the heavy oil micro-reaction evaluation device (ACE).

[0221] The results of the catalytic cracking reaction selectivity evaluation of CAT-1 and DCAT-2 aids are shown in Table 4. In Table 4, total liquid yield = liquefied gas yield + gasoline yield + diesel yield; coke factor = (100 - conversion rate) x coke yield / conversion rate.

[0222] Table 4

[0223]

[0224] The results in Table 4 show that, compared with the comparative aid DCAT-3 of Comparative Example 3, the addition of the catalytic cracking aid CAT-5 of Example 5 in the LDC-200 industrial catalyst increases the conversion rate of the catalytic cracking reaction, reduces the heavy oil yield, reduces the coke factor, increases the total liquid yield, and increases the yield of low-carbon olefins (ethylene + propylene + butene). It is shown that, compared with the prior art, the use of the aid provided by the application promotes the efficient conversion of heavy oil, reduces the tendency to coke, while being prolific in low-carbon olefins, and improves the selectivity of the catalytic cracking reaction.

[0225] Test Example 4

[0226] This test example is used to evaluate the performance of the catalytic cracking aids of Example 3 and Comparative Examples 4 and 5.

[0227] The catalytic cracking aids CAT-3, CAT-6 and CAT-7 prepared in Example 3, Example 6 and Example 7 are used as the test samples, the industrial catalyst LDC-200 is mixed with the test samples in a weight ratio of 9:1 to obtain three groups of catalyst mixtures, and the three groups of catalyst mixtures are respectively subjected to aging treatment at 800°C and 100% steam for 17h, and then the catalytic cracking reaction performance is evaluated on a heavy oil micro-reaction evaluation device (ACE). The evaluation results are shown in Table 5.

[0228] In Table 5, the total liquid yield = LPG yield + gasoline yield + diesel yield; the coke factor = (100- conversion rate) x coke yield / conversion rate.

[0229] Table 5

[0230]

[0231] The results in Table 5 show that the catalytic cracking aids prepared in Example 3, Example 6 and Example 7 of the application all have high conversion rate and total liquid yield. Compared with Example 6 and Example 7, the catalytic effect of the catalytic cracking aid of Example 3 is slightly improved, which shows that titanium tetrachloride and n-hexane, and the waste liquid containing titanium tetrachloride can all be used as modified titanium sources, which helps to improve the selectivity of the catalytic reaction of the aid. Example 6 and Example 7 use pure titanium tetrachloride, the combination of pure titanium tetrachloride and n-hexane instead of the waste liquid containing titanium tetrachloride to prepare the molecular sieve, and the catalytic cracking aids CAT-6 and CAT-7 prepared also have good catalytic cracking reaction selectivity.

Claims

1. A catalytic cracking aid, wherein, The raw material of the catalytic cracking aid comprises, based on 100% by weight of the raw material of the catalytic cracking aid: 15%-55% of modified ZSM-5 molecular sieve, 10%-55% of clay, 3%-20% of aluminum source, and 5%-20% of phosphorus from a second modifier, wherein the weight of the modified ZSM-5 molecular sieve, the clay, and the aluminum source is based on dry basis, and the weight of the phosphorus is based on oxide; The preparation method of the modified ZSM-5 molecular sieve comprises: mixing raw ZSM-5 and a titanium source of a first modifier to form a mixed solution, and performing first calcination; mixing the product of the first calcination and a phosphorus source of the first modifier, and performing second calcination to obtain the modified ZSM-5 molecular sieve; and the first modifier comprises the titanium source and the phosphorus source.

2. The catalytic cracking aid of claim 1, wherein, The preparation method of the modified ZSM-5 molecular sieve comprises: fully impregnating raw ZSM-5 molecular sieve with an impregnation solution containing a titanium source, drying, and performing first calcination; mixing the product of the first calcination and a phosphorus source of the first modifier, and performing second calcination to obtain the modified ZSM-5 molecular sieve; and the first modifier comprises the titanium source and the phosphorus source.

3. The catalytic cracking aid of claim 1 or 2, wherein, The modified ZSM-5 molecular sieve comprises 0.2%-25% of titanium and 0.2%-6% of phosphorus, based on 100% by weight of the total weight of the modified ZSM-5 molecular sieve, wherein the weight of the titanium and the phosphorus is based on oxide, respectively.

4. The catalytic cracking aid of claim 3, wherein, The modified ZSM-5 molecular sieve further comprises a modified metal element, and the first modifier further comprises a modified metal source. The weight percentage of the modified metal element from the first modifier in the modified ZSM-5 molecular sieve is 0-5% and not 0, based on oxide of the modified metal element. The modified metal element comprises one or a combination of two or more of iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium.

5. The catalytic cracking aid of claim 1 or 2, wherein, The temperature of the first calcination is 450-650 DEG C, and the time of the first calcination is 1-4 hours. The temperature of the second calcination is 450-650 DEG C, and the time of the second calcination is 1-4 hours.

6. The catalytic cracking aid of claim 1, wherein, The pH value of the mixed solution is 0.5-8.

7. The catalytic cracking aid of claim 6 wherein, The pH value of the mixed solution is 0.5-3.

8. The catalytic cracking aid of claim 2 wherein, The pH value of the impregnation solution is 0.5-8.

9. The catalytic cracking aid of claim 8 wherein, The pH value of the impregnation solution is 0.5-3.

10. The catalytic cracking aid of claim 1, wherein, The aluminum source comprises one or a combination of two or more of pseudoboehmite, amorphous alumina, boehmite, aluminum nitrate, and aluminum chloride.

11. The catalytic cracking aid of claim 1, wherein, The clay comprises one or a combination of two or more of kaolin, montmorillonite, diatomite, and sepiolite.

12. The catalytic cracking aid of claim 1, wherein, The clay comprises one or a combination of two or more of halloysite and bentonite.

13. The catalytic cracking aid of claim 1, wherein, The second modifier comprises a phosphorus source. In the first modifier and the second modifier, the phosphorus source comprises one or a combination of two or more of phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphoric acid, pyrophosphate, polyphosphoric acid, polyphosphate, metaphosphoric acid, and metaphosphate.

14. The catalytic cracking aid of claim 13, wherein, In the first modifier and the second modifier, the phosphorus source comprises one or a combination of two or more of phosphoric acid, ammonium phosphate, diammonium hydrogen phosphate, ammonium hydrogen phosphate, magnesium phosphate, aluminum phosphate, phosphorous acid, ammonium phosphite, sodium pyrophosphate, sodium tripolyphosphate, and sodium hexametaphosphate.

15. The catalytic cracking aid of claim 13, wherein, The second modifier further comprises a titanium source, the titanium from the second modifier in the raw material of the catalytic cracking aid is 0-10% by weight and not 0, calculated as titanium oxide.

16. The catalytic cracking aid of claim 1, wherein, The titanium source of the first modifier comprises titanium tetrachloride.

17. The catalytic cracking aid of claim 16, wherein, The titanium source of the first modifier comprises titanium tetrachloride and hexane in a weight ratio of (4-34):

1.

18. The catalytic cracking aid of claim 16, wherein, The titanium source of the first modifier comprises a waste liquid containing titanium tetrachloride, the waste liquid containing titanium tetrachloride comprises, calculated as 100% of the total weight of the waste liquid containing titanium tetrachloride: titanium tetrachloride 80%-95%, titanium alkoxy complex 2%-5%, and the balance is hydrocarbon, and the hydrocarbon comprises hexane.

19. The catalytic cracking aid of claim 15, wherein, The titanium source of the second modifier comprises titanium tetrachloride.

20. The catalytic cracking aid of claim 19, wherein, The titanium source of the second modifier comprises titanium tetrachloride and hexane in a weight ratio of (4-34):

1.

21. The catalytic cracking aid of claim 19, wherein, The titanium source of the second modifier comprises a waste liquid containing titanium tetrachloride, the waste liquid containing titanium tetrachloride comprises, calculated as 100% of the total weight of the waste liquid containing titanium tetrachloride: titanium tetrachloride 80%-95%, titanium alkoxy complex 2%-5%, and the balance is hydrocarbon, and the hydrocarbon comprises hexane.

22. The catalytic cracking aid of claim 13, wherein, The second modifier further comprises a modified metal source for providing a modified metal element, the modified metal element from the second modifier in the raw material of the catalytic cracking aid is 0-5% by weight and not 0, calculated as oxide of the modified metal element. The modified metal element comprises one or a combination of two or more of iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium elements.

23. The catalytic cracking aid of claim 1, wherein, The catalytic cracking aid further comprises a binder, the weight of the binder, calculated as oxide of the binder, is 0-10% of the weight of the raw material of the catalytic cracking aid and not 0.

24. The catalytic cracking aid of claim 1, wherein, The raw material of the catalytic cracking aid comprises 20%-50% of the modified ZSM-5 molecular sieve on a dry basis, calculated as 100% of the weight of the raw material of the catalytic cracking aid. And / or, the raw material of the catalytic cracking aid comprises 6%-19% of the phosphorus from the second modifier, calculated as oxide, calculated as 100% of the weight of the raw material of the catalytic cracking aid.

25. A method for preparing the catalytic cracking aid according to any one of claims 1-24, the method comprising: mixing the modified ZSM-5 molecular sieve, clay, aluminum source, and second modifier to form a raw material slurry; spray drying and calcining the raw material slurry to obtain the catalytic cracking aid.

26. The method of manufacturing according to claim 25, wherein, The method further comprises acidizing at least one of the modified ZSM-5 molecular sieve and clay and the aluminum source.

27. The method of making according to claim 26, wherein, The acidizing is performed at a temperature of 40-90°C for a time period of 0.5h-3h.

28. The method of making according to claim 25, wherein, The raw material slurry further comprises a pore structure improver.

29. The method of making according to claim 28, wherein, The pore structure improver comprises one or a combination of two or more of 1,3,5-trimethylbenzene, 1,3,5-triisopropylbenzene, methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, and polyethylene glycol.

30. The method of making according to claim 28, wherein, The pore structure improver is present in an amount of 0.1%-10% of the weight of the raw material of the catalytic cracking aid.

31. Use of the catalytic cracking aid according to any one of claims 1-24 in a catalytic cracking process.

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