Catalytic cracking catalyst and method for its preparation

Abstract

The application provides a catalytic cracking catalyst and a preparation method thereof. The composition of the catalyst comprises: 15-55% of modified ZSM-5 molecular sieve in dry basis, 0.5-10% of Y-type molecular sieve in dry basis, 0-5% of high-silicon ZSM-5 molecular sieve in dry basis, 5-55% of clay in dry basis, 0-25% of pseudo-boehmite in dry basis, 4-70% of titanium-containing composite binder in dry basis, 0-15% of binder in oxide, 0-30% of inorganic oxide carrier material in oxide, 0-20% of phosphorus in oxide and 0-5% of modified metal compound in oxide. The catalytic cracking catalyst can promote the conversion of heavy oil, reduce the heavy oil yield and reduce the coking tendency in the catalytic cracking process, and has high low-carbon olefin yield, excellent reaction selectivity and use performance.

Description

Technical Field

[0001] This invention belongs to the field of refining catalysts and additives, and relates to a catalytic cracking catalyst, specifically a catalytic cracking catalyst for reducing coke yield and increasing low-carbon olefin yield, and its preparation method. Background Technology

[0002] In the industrial production of polyolefins, the most widely used catalyst is the Ziegler-Natta catalyst, a titanium-based catalyst. Regarding the preparation of titanium-based polyolefin catalysts, for example, patent CN102336851B discloses a propylene polymerization catalyst comprising magnesium, titanium, halogens, and a mixture of one of the internal electron donor compounds, diisobutyl phthalate, diethyl phthalate, or di-n-butyl phthalate, and a succinate ester; patent CN107434832B discloses a propylene polymerization catalyst mainly composed of magnesium alkoxides, titanium compounds, and phosphate ester electron donor compounds. Currently, a common method for preparing titanium-based catalysts is as follows: first, magnesium halide alcohols are prepared, for example, by heating and dissolving magnesium halide with an alcohol, followed by high-pressure spraying or high-speed stirring, and then solidifying into microspheres in a cooling medium; specific steps are described in CN1110281A. Then, the magnesium halide alcohol particles are reacted with a halogen-containing compound such as titanium tetrachloride to prepare a magnesium-supported catalyst, during which various promoters can be added for modification. In the catalyst preparation process described above, a large amount of titanium tetrachloride is required, and in significant excess. Simultaneously, the obtained solid catalyst component needs to be washed with a hydrocarbon solvent (such as hexane) to remove unloaded titanium tetrachloride. Therefore, in the production of polyolefin catalysts, after separating and precipitating the solid catalyst, a large amount of catalyst mother liquor containing at least one of the following substances is generated: titanium tetrachloride, unreacted hydrocarbons, unreacted haloalkoxytitanium, alkoxymagnesium, and unreacted esters. The preparation of titanium-based polypropylene catalysts generates a large amount of waste liquid containing titanium tetrachloride, which, in addition to containing titanium tetrachloride (at least 80%), also contains small amounts of alkoxytitanium complexes (e.g., approximately 2-5%), small amounts of lipids, and n-hexane. Directly discarding this waste liquid would inevitably cause environmental pollution and resource waste; therefore, its effective utilization is necessary.

[0003] Regarding the treatment and utilization of titanium tetrachloride-containing waste liquid generated during the preparation of polypropylene catalysts, CN106277046B discloses a method for treating titanium tetrachloride-containing waste liquid, which contains titanium tetrachloride, organic solvents, and haloalkoxy titanium and / or alkoxy titanium. The method includes: (1) contacting the titanium tetrachloride-containing waste liquid with water to perform hydrolysis; (2) distilling the above-mentioned hydrolyzed waste liquid and collecting titanium-containing compounds from the remaining material.

[0004] CN112723430 A discloses a method for treating and recovering waste liquid from the production of polyolefin catalysts. The method includes: (1) introducing the waste liquid from the production of polyolefin catalysts and hydrolyzed water into a hydrolysis reactor for continuous hydrolysis to obtain a gaseous stream I and a solid-liquid mixed stream; (2) incinerating the solid-liquid mixed stream to obtain a gaseous stream II and a solid stream I containing TiO2; (3) removing dust from the gaseous stream I and the gaseous stream II to obtain a gaseous stream III and a solid stream II containing TiO2; and (4) absorbing the gaseous stream III with hydrochloric acid. This method achieves a pollution-free discharge treatment process for waste liquid from the production of polyolefin catalysts, and also realizes the resource recovery of Cl and Ti elements in the waste liquid.

[0005] Regarding the preparation of titanium sol, titanium-containing molecular sieves, titanium-containing catalytic materials, titanium-containing catalysts, and additives from titanium tetrachloride, CN107866211 B discloses a TiO2 sol and a catalytic cracking catalyst, as well as their preparation methods. The titanium-chloride molar ratio of the TiO2 sol is (0.2-0.6):1; and the corrosion rate of the TiO2 sol is ≤1 g / m³. 2 The provided TiO2 sol, with a pH of 5-8 and a viscosity ≥1000 mPa·s at 20℃, possesses high viscosity, low corrosion rate, and high pH value. When used as a binder in the preparation of catalytic cracking catalysts, it helps increase the specific surface area of ​​the catalyst, improves its sphericity, enhances its activity, and improves the product distribution of the catalytic cracking reaction, primarily benefiting the formation of the target product, gasoline.

[0006] CN102114429 B discloses a method for increasing the Brønsted acid content of ZSM-5 molecular sieve and achieving increased production of low-carbon olefins. The method involves simultaneously modifying the ZSM-5 molecular sieve with iron and titanium. After modification, the mass ratio of iron to titanium in the molecular sieve is 0.3-3:1, which improves the catalytic reactivity of the molecular sieve and promotes the conversion of long-chain alkanes and aromatics with long-chain alkyl side chains, such as cumene, thereby significantly increasing the yield of low-carbon olefins.

[0007] CN109694721 B discloses a macroporous kaolinite and its preparation and application. The macroporous kaolinite contains a modified metal, has an average pore diameter of 2-50 nm, and pores with a diameter of 10-50 nm account for more than 80% of the total pore volume. The modified metal is one or more of alkaline earth metals, titanium, and zirconium. The preparation method of the macroporous kaolinite includes: first calcining kaolin; mixing the first calcined kaolin with a first acid, water, and optionally a modified metal compound, performing a first treatment, followed by a second calcination; then mixing with a second acid, water, a pore-expanding agent, and optionally a modified metal compound for a second treatment; filtering and drying to obtain the macroporous kaolinite. At least one step in the first and second treatments involves adding a modified metal compound. The macroporous kaolinite can be used to prepare cracking catalysts, resulting in catalysts with high heavy oil conversion activity, high gasoline and liquefied petroleum gas yields, low dry gas selectivity, and low coke selectivity.

[0008] CN105618107 B discloses a catalytic cracking catalyst and its preparation method. Based on the total weight of the catalyst, the catalyst contains 10-60 wt% titanium and / or zirconium-modified Y molecular sieve, 10-60 wt% clay, and 5-50 wt% binder; the titanium and / or zirconium-modified Y molecular sieve contains 1.0 wt%-15.0 wt% titanium and / or zirconium metal oxide. The catalyst preparation method includes the steps of preparing the titanium and / or zirconium-modified Y molecular sieve, preparing a catalyst slurry, and spray drying. The titanium and / or zirconium-modified Y molecular sieve includes the following steps: (1) dispersing a titanium and / or zirconium-containing compound in water and adjusting the pH of the mixture to 3-10; (2) mixing the molecular sieve with the mixture obtained in step (1) and stirring; optionally filtering and / or drying; (3) calcining at 300-700℃. This catalyst exhibits high heavy oil conversion capacity and gasoline yield.

[0009] In the existing technology, the titanium tetrachloride-containing waste liquid generated during the preparation of polypropylene catalysts is usually separated from the waste liquid; the preparation process of titanium-containing kaolinite is complicated and requires multiple additions of acid and filtration treatment during the preparation process; modified ZSM-5 molecular sieves and corresponding catalytic cracking catalysts are not used to reduce coking tendency or reduce heavy oil yield.

[0010] Therefore, in order to solve the problem of treating the large amount of titanium tetrachloride-containing waste liquid generated during the preparation of polypropylene catalysts, and to address the unfavorable factors of high heavy oil yield, high coke production, and low low-carbon olefin yield during catalytic cracking, despite recent catalyst technologies, there is still a need for new catalytic cracking catalyst preparation technologies that are simple and feasible to prepare while possessing excellent performance. Summary of the Invention

[0011] To address the aforementioned problems, the present invention aims to provide a catalytic cracking catalyst and its preparation method. This catalytic cracking catalyst, when used in the catalytic cracking process, can promote the conversion of heavy oil, reduce the yield of heavy oil, reduce the tendency to produce coke, and simultaneously achieve a high yield of low-carbon olefins, exhibiting excellent reaction selectivity and performance.

[0012] To achieve the above objectives, the present invention provides a catalytic cracking catalyst, which, based on 100% by weight, comprises: 15-55% (dry basis) modified ZSM-5 molecular sieve, 0-5% (dry basis) high-silica ZSM-5 molecular sieve, 0.5-10% (dry basis) Y-type molecular sieve, 5-55% (dry basis) clay, 0-25% (dry basis) boehmite, 4-70% (dry basis) titanium-containing composite binder, 0-15% (dry basis) binder, 0-30% (dry basis) inorganic oxide support material, and 0-20% (dry basis)... The titanium-containing composite adhesive comprises phosphorus (calculated as oxide) and 0-5% modified metal compound (calculated as oxide); wherein the preparation method of the titanium-containing composite adhesive includes the following steps: (1) mixing calcined clay, water, and titanium tetrachloride solution to obtain a mixture; (2) reacting the above mixture at 40-120°C for 0.5-6 h to obtain the titanium-containing composite adhesive; based on the dry basis of the titanium-containing composite adhesive being 100%, the composition of the titanium-containing composite adhesive includes 7-45 wt% titanium (calculated as oxide), 0.6-40 wt% aluminum (calculated as oxide), and 30-92 wt% silicon (calculated as oxide).

[0013] According to a specific embodiment of the present invention, preferably, the preparation method of the modified ZSM-5 molecular sieve includes the following steps: (a) mixing ZSM-5 molecular sieve slurry, titanium tetrachloride solution, and one or more compounds selected from iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium, contacting at 4-150°C for 10 min-2 h, drying, and calcining to obtain a mixture; (b) mixing the mixture obtained in step (a) with a phosphorus-containing compound, contacting at 4-150°C for 10 min-2 h, drying, and calcining to obtain the modified ZSM-5 molecular sieve; calculated based on 100% by weight of the modified ZSM-5 molecular sieve, the composition of the modified ZSM-5 molecular sieve includes 0.2-25% titanium as oxide, 0-5% total of iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium as oxide, and 0.2-6% phosphorus as oxide.

[0014] According to a specific embodiment of the present invention, preferably, the composition of the catalytic cracking catalyst, calculated as 100% by weight, comprises: 20-50% modified ZSM-5 molecular sieve on a dry basis, 2-8% Y-type molecular sieve on a dry basis, 10-50% clay on a dry basis, 3-15% boehmite on a dry basis, 6-40% titanium-containing composite binder on a dry basis, 0-6% binder on an oxide basis, 3-18% phosphorus on an oxide basis, and 0.2-3% modified metal compound on an oxide basis.

[0015] According to a specific embodiment of the present invention, preferably, the solid content of the titanium-containing composite adhesive is 10-45 wt%.

[0016] According to a specific embodiment of the present invention, preferably, the titanium-containing composite adhesive comprises 7-30 wt% titanium as oxide, 8-40 wt% aluminum as oxide, and 35-70 wt% silicon as oxide, based on a dry basis of 100%.

[0017] According to a specific embodiment of the present invention, preferably, in the preparation method of the titanium-containing composite adhesive, the mixed raw materials further include a dispersant; calculated on a dry basis of 100% of the titanium-containing composite adhesive, the content of the dispersant is less than 10%, more preferably 0.3-5%.

[0018] According to a specific embodiment of the present invention, preferably, the dispersant comprises one or more of 1,3,5-trimethylbenzene, 1,3,5-triisopropylbenzene, methylcellulose, carboxymethylcellulose, polyvinyl alcohol, and polyethylene glycol.

[0019] According to a specific embodiment of the present invention, preferably, in the preparation method of the titanium-containing composite binder or the modified ZSM-5 molecular sieve, the titanium tetrachloride solution is titanium tetrachloride waste liquid; the titanium tetrachloride waste liquid is titanium tetrachloride-containing waste liquid generated during the preparation of polypropylene catalyst. The titanium tetrachloride solution can be pure titanium tetrachloride.

[0020] According to a specific embodiment of the present invention, preferably, in the preparation method of the titanium-containing composite binder, the clay includes one or more of kaolin, hydrous kaolin, montmorillonite, diatomite, halloysite, sepiolite, and bentonite; more preferably, it is one or more of kaolin, hydrous kaolin, diatomite, halloysite, and sepiolite.

[0021] According to a specific embodiment of the present invention, preferably, in the preparation method of the titanium-containing composite binder, the calcination is carried out at 400-900°C for 0.5-6 hours.

[0022] According to a specific embodiment of the present invention, preferably, the preparation method of the titanium-containing composite adhesive includes the following steps: mixing clay calcined at 550-850℃ for 1-3 hours, water, and waste liquid containing titanium tetrachloride to form a mixture, and heating to 60-120℃ to react for 0.5-3 hours to obtain the titanium-containing composite adhesive.

[0023] According to a specific embodiment of the present invention, preferably, in the preparation method of the titanium-containing composite adhesive, after the reaction in step (2) is completed, the pH value of the reaction system is 0.5-8; more preferably, an alkaline substance is used to adjust the pH value of the reaction system to 0.5-8; more preferably, the alkaline substance is selected from one or more combinations of ammonia, ammonium carbonate, ammonium bicarbonate, water glass, sodium aluminate, magnesium oxide, magnesium hydroxide, magnesium carbonate, calcium oxide, calcium hydroxide, and calcium carbonate.

[0024] According to a specific embodiment of the present invention, preferably, in step (1), the clay is pulverized before or after calcination until the average particle size D(v, 0.5) < 4 μm, and then mixed with water and titanium tetrachloride solution.

[0025] According to a specific embodiment of the present invention, preferably, the silicon-aluminum molar ratio of the high-silicon ZSM-5 molecular sieve is 200 or higher.

[0026] According to a specific embodiment of the present invention, preferably, in the preparation method of the modified ZSM-5 molecular sieve, the compounds of iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium are one or a combination of two or more of the oxides, chlorides, nitrates, carbonates, sulfates, oxalates, and acetates of iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium.

[0027] According to a specific embodiment of the present invention, preferably, in the preparation method of the modified ZSM-5 molecular sieve, the phosphorus-containing compound includes one or more combinations of phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphate, pyrophosphate, polyphosphate, polyphosphate, metaphosphate, and metaphosphate.

[0028] According to a specific embodiment of the present invention, preferably, in the preparation method of the modified ZSM-5 molecular sieve, the phosphorus-containing compound includes one or more of the following: phosphoric acid, ammonium phosphate, ammonium hydrogen phosphate, diammonium hydrogen phosphate, magnesium phosphate, aluminum phosphate, phosphorous acid, ammonium phosphite, sodium pyrophosphate, sodium tripolyphosphate, and sodium hexametaphosphate.

[0029] According to a specific embodiment of the present invention, preferably, in the preparation method of the modified ZSM-5 molecular sieve, the calcination temperature in steps (a) and (b) is 450-650℃, and the calcination time is 1h-4h.

[0030] According to a specific embodiment of the present invention, preferably, in the preparation method of the modified ZSM-5 molecular sieve, the titanium tetrachloride solution and / or the compound selected from iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium are adjusted to pH 0.5-8 with an alkaline substance before being mixed with the ZSM-5 molecular sieve slurry.

[0031] According to a specific embodiment of the present invention, preferably, in the preparation method of the modified ZSM-5 molecular sieve, the alkaline substance includes one or more of ammonia, ammonium carbonate, ammonium bicarbonate, water glass, magnesium oxide, magnesium hydroxide, and magnesium carbonate.

[0032] According to a specific embodiment of the present invention, preferably, the modified ZSM-5 molecular sieve comprises, by weight 100%, 0.2-25% titanium (calculated as oxides), 0-5% iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium and yttrium (calculated as oxides), and 0.2-6% phosphorus (calculated as oxides).

[0033] According to a specific embodiment of the present invention, preferably, the modified ZSM-5 molecular sieve contains titanium and phosphorus, and may also contain one or more elements selected from iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium. The titanium is derived from the waste liquid containing titanium tetrachloride generated during the preparation of the polypropylene catalyst. The iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium elements are derived from one or more oxides, chlorides, nitrates, carbonates, sulfates, oxalates, and acetates of iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium.

[0034] According to a specific embodiment of the present invention, preferably, the Y-type molecular sieve includes one or more of HY, NH4Y, hydrothermally ultrastable Y-type molecular sieve, silicon tetrachloride gas-phase ultrastable Y-type molecular sieve, rare earth-containing (e.g., yttrium) Y-type molecular sieve, and phosphorus-modified ultrastable Y-type molecular sieve; the rare earth-containing (e.g., yttrium) Y-type molecular sieve includes one or two of rare earth-modified (e.g., yttrium) ultrastable Y-type molecular sieve, and phosphorus and rare earth co-modified (e.g., yttrium) ultrastable Y-type molecular sieve.

[0035] According to a specific embodiment of the present invention, preferably, the clay is selected from one or more combinations of kaolin, hydrous kaolin, montmorillonite, diatomite, halloysite, sepiolite, and bentonite, and more preferably from one or more combinations of kaolin, hydrous kaolin, diatomite, halloysite, and sepiolite.

[0036] According to a specific embodiment of the present invention, preferably, the adhesive comprises one or a combination of two or more of aluminum sol, silica sol, aluminosilicate, and aluminum phosphate adhesive.

[0037] According to a specific embodiment of the present invention, preferably, the inorganic oxide carrier material includes one or more of the following: silica, alumina material containing Brønsted acid centers, and aluminosilicate material containing Brønsted acid centers; the alumina material containing Brønsted acid centers and the aluminosilicate material containing Brønsted acid centers have high pore volume, large specific surface area, dual pore distribution, high thermal stability and high acidity, and contain Brønsted acid centers.

[0038] According to a specific embodiment of the present invention, preferably, the phosphorus is derived from one or more combinations of phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphate, pyrophosphate, polyphosphate, polyphosphate, metaphosphate, and metaphosphate; more preferably, the phosphorus is derived from one or more combinations of phosphoric acid, ammonium phosphate, ammonium hydrogen phosphate, diammonium hydrogen phosphate, magnesium phosphate, aluminum phosphate, phosphorous acid, ammonium phosphite, sodium pyrophosphate, sodium tripolyphosphate, and sodium hexametaphosphate.

[0039] According to a specific embodiment of the present invention, preferably, the modified metal compound includes one or more of the oxides, chlorides, nitrates, carbonates, sulfates, oxalates, and acetates of iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium.

[0040] According to a specific embodiment of the present invention, preferably, the composition of the catalytic cracking catalyst further includes a pore structure improver; the weight of the pore structure improver is 0.1-10% of the total weight of the catalytic cracking catalyst; more preferably 0.3-6%, and even more preferably 0.3-5%, so as to improve the pore structure, specific surface area and other properties of the catalyst.

[0041] According to a specific embodiment of the present invention, preferably, the pore structure improver includes one or more of 1,3,5-trimethylbenzene, 1,3,5-triisopropylbenzene, methylcellulose, carboxymethylcellulose, polyvinyl alcohol, and polyethylene glycol.

[0042] The catalytic cracking catalyst of the present invention can treat the waste liquid containing titanium tetrachloride generated during the preparation of polypropylene catalyst through the following technical solutions: (1) ZSM-5 molecular sieve is modified with waste liquid containing titanium tetrachloride and phosphorus compounds, which modulates the acidity of the molecular sieve and improves its stability; (2) After clay is calcined at high temperature, its crystal structure changes. For example, the silicon and aluminum contained in kaolin are mainly composed of kaolinite structure. After high temperature calcination, kaolinite undergoes a phase transformation to form active silicon and active aluminum. This active silicon and active aluminum can react with acid or alkali; titanium tetrachloride hydrolyzes to produce titanium oxide and hydrogen chloride. Utilizing the aforementioned properties of clay and titanium tetrachloride, calcined clay is treated using waste liquid containing titanium tetrachloride. The calcined clay is mixed with water and the waste liquid containing titanium tetrachloride, allowing the hydrochloric acid produced by the hydrolysis of titanium tetrachloride to react with the active aluminum in the calcined clay, thus preparing a composite binder containing titanium and clay. As the active aluminum in the clay reacts with the hydrochloric acid produced by the hydrolysis of titanium tetrachloride, the active aluminum detaches from the clay, forming mesopores and macropores in the clay. At the same time, the active aluminum reacting with the hydrochloric acid and the fine titanium oxide particles produced by hydrolysis together form a titanium-aluminum mixture, which, together with the aforementioned mesopore clay, forms a composite binder containing titanium and clay. This titanium-containing composite binder not only functions as a binder but also contains mesoporous and macroporous clay components, which helps improve the pore structure of the catalyst, increase the proportion of mesoporous and macroporous components, and improve diffusion performance; (3) The organic matter contained in the waste liquid containing titanium tetrachloride (the waste liquid mainly contains titanium tetrachloride, accounting for 80%-95% by weight, the remainder is mainly hexane, and also contains a small amount of alkoxy titanium complex (about 2-5% by weight), and a small amount of lipids) can also act as a template agent between the components of the molecular sieve or catalyst, decompose and form channels during the high-temperature treatment process of molecular sieve or catalyst preparation, improve the pore structure of the molecular sieve or catalyst, and improve diffusion performance. The utilization of waste liquid containing titanium tetrachloride is convenient, and it is not necessary to separate the titanium, chlorine and organic matter in the waste liquid containing titanium tetrachloride, without increasing equipment investment and treatment costs.

[0043] The present invention also provides a method for preparing the above-mentioned catalytic cracking catalyst, which includes the following steps: (1) mixing and slurrying the modified ZSM-5 molecular sieve, Y-type molecular sieve, clay, pseudoboehmite, titanium-containing composite binder, binder, inorganic oxide support material, phosphorus compound, and modified metal compound (preferably with added pore structure improver) to obtain a slurry; (2) spray drying the slurry to form a shape, and then calcining and solidifying it to obtain the catalytic cracking catalyst.

[0044] According to a specific embodiment of the present invention, preferably, the modified ZSM-5 molecular sieve and Y-type molecular sieve in step (1) are subjected to sand milling before mixing and pulping and / or the slurry in step (2) is subjected to sand milling before spray drying, so that the average particle size D(v, 0.5) of the modified ZSM-5 molecular sieve and Y-type molecular sieve in step (1) and / or the slurry in step (2) is < 4 μm.

[0045] According to a specific embodiment of the present invention, preferably, the pseudoboehmite is used after being acidified and then aged at 40-90°C for 0.5-3 hours for gelation, or after being mixed with other components and then aged; in the process of acidifying the pseudoboehmite, the acid is an inorganic acid, such as one or more of hydrochloric acid, sulfuric acid, and nitric acid.

[0046] According to a specific embodiment of the present invention, preferably, the ZSM-5 molecular sieve is a mesoporous ZSM-5 molecular sieve.

[0047] This invention is not limited to a spray drying method; techniques known to those skilled in the art can be employed, with process conditions such as controlling the spray tower furnace temperature at 450-550℃ and the spray exhaust gas temperature at 200-300℃. This invention can control the sieving distribution of spray-formed catalyst microspheres by controlling spray forming conditions such as spray pressure and nozzle size.

[0048] The titanium tetrachloride-containing waste liquid generated during the preparation of polypropylene catalysts, with a titanium tetrachloride content of approximately 80%-95% (by weight), will inevitably cause environmental pollution and resource waste if discharged into the environment. The catalytic cracking catalyst of this invention has a simple and feasible preparation process, and the titanium content can be adjusted within a wide range. The prepared catalytic cracking catalyst uses titanium tetrachloride-containing waste liquid, which not only solves the problem of waste liquid treatment and avoids environmental pollution, but also reduces the high treatment costs. Simultaneously, the performance of the titanium-containing catalytic cracking catalyst of this invention is improved: the titanium-containing catalytic cracking catalyst prepared by this invention, when used in the catalytic cracking process, can promote the conversion of heavy oil, reduce heavy oil yield, reduce coking tendency, and achieve high low-carbon olefin yield. Detailed Implementation

[0049] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0050] The elemental content of the following samples and catalysts was determined by X-ray fluorescence analysis. The attrition index of the catalyst was analyzed using an MS-C / 6 attrition index analyzer manufactured by Shenyang Kehui Instrument Manufacturing Co., Ltd. The pore volume of the catalyst was determined using the water droplet method.

[0051] The origin and specifications of the raw materials used are as follows:

[0052] (1) Waste liquid containing titanium tetrachloride generated during the preparation of polypropylene catalyst (hereinafter referred to as: waste liquid containing titanium tetrachloride): titanium content 90% (calculated as TiCl4), provided by Lanzhou Chemical Research Center of Petroleum and Chemical Research Institute of China National Petroleum Corporation; kaolin (loss on ignition 29wt%), halloysite (loss on ignition 16.6wt%), pseudoboehmite (loss on ignition 36wt%), alumina sol (containing alumina 21.6wt%), silica sol (silicon oxide concentration 30wt%), ordinary ZSM-5 molecular sieve (silicon-to-alumina ratio 31, mesopore volume 0.04mL / g), high-silicon ZSM-5 molecular sieve (silicon-to-alumina ratio 384), GUSY-1 molecular sieve (silicon tetrachloride gas-phase ultrastable molecular sieve, Na2O content 1.3wt%, RE2O3 content 2.7wt%, relative crystallinity 55%, cell constant (4wt% reduction), REHY molecular sieve (Na2O content 1.5wt%, RE2O3 content 8.2wt%, 5wt% reduction), rare earth chloride solution (content of RE2O3 289.3g / l): all are industrial products, sourced from Lanzhou Petrochemical Company Catalyst Plant.

[0053] (2) Mesoporous ZSM-5 molecular sieve: silica-alumina ratio 30, mesopore volume 0.29 mL / g;

[0054] (3) Diatomaceous earth (loss on ignition 2.6 wt%), silica: industrial grade;

[0055] (4) Titanium tetrachloride, magnesium chloride, phosphoric acid (concentration 85%), diammonium hydrogen phosphate, lanthanum oxide, ferric nitrate (Fe(NO3)3·9H2O), zirconium oxide, zirconium sulfate, polyethylene glycol, and carboxymethyl cellulose: are all chemical reagents;

[0056] (5) Hydrochloric acid: 36% concentration, chemical reagent; Nitric acid: 65-68% concentration, chemical reagent; Ammonia: 18% concentration, chemical reagent.

[0057] The spray drying methods for the catalytic cracking catalysts in Examples 1-4 and Comparative Examples 1-6 used the following process conditions: the temperature of the spray tower furnace was controlled at 450°C, the temperature of the spray exhaust gas was controlled at 200°C, and the particle size range of the obtained catalysts was 65-78 μm.

[0058] Example 1

[0059] This embodiment provides a catalytic cracking catalyst, the preparation method of which is as follows:

[0060] 1. Preparation of modified ZSM-5 molecular sieve:

[0061] (1) Add 1.5 kg of mesoporous ZSM-5 molecular sieve (dry basis) to 3.9 L of deionized water, stir evenly, then add 127 g of waste liquid containing titanium tetrachloride, adjust the pH value to 1.0 with ammonia water, stir at room temperature (25℃) for 0.5 h to form molecular sieve slurry, dry at 120℃, and calcine at 500℃ for 1 h.

[0062] (2) The molecular sieve calcined in step (1) was mixed with 2.4L of deionized water, 73g of phosphoric acid was added, the mixture was stirred evenly, and then placed in a high pressure vessel and kept at 120℃ for 1h. Then it was dried at 120℃ and calcined at 500℃ for 1h to obtain titanium and phosphorus modified mesoporous ZSM-5 molecular sieve Z-1.

[0063] 2. Preparation of composite adhesives containing titanium and clay:

[0064] Kaolin was calcined at 750℃ for 2 hours to obtain calcined material. 1674g (dry basis) of the calcined material was crushed to an average particle size D(v, 0.5) < 4μm. 5.16L of decationized water was added and stirred. 332g of waste liquid containing titanium tetrachloride and 18g of polyethylene glycol were added. The temperature was raised to 70℃ and stirred for 1 hour. The pH value was 3.5, and a composite binder M-1 containing titanium and clay was obtained.

[0065] The composition of the titanium-clay composite binder M-1 is as follows: 93 wt% (dry basis) of kaolin roasting material, 7 wt% (calculated as titanium oxide) of titanium from waste liquid containing titanium tetrachloride, and 25 wt% of solid content of the titanium-clay composite binder M-1.

[0066] 3. Preparation of catalytic cracking catalysts:

[0067] 0.66 kg of kaolin (dry basis), 1.68 kg of titanium- and clay-containing composite binder M-1, 0.24 kg of pseudoboehmite (dry basis), and 2.9 L of deionized water were added to a pulping tank and stirred for 1 h. Then, 32 mL of hydrochloric acid was added, and the mixture was stirred for 0.5 h and aged at 50 °C for 2 h. Next, 1.08 kg of modified mesoporous ZSM-5 molecular sieve Z-1 (dry basis) and 120 g (dry basis) of GUSY-1 molecular sieve were added and stirred for 15 minutes. Then, 0.223 kg of diammonium hydrogen phosphate, 0.585 kg of phosphoric acid, and 30 g of carboxymethyl cellulose were added and mixed and pulped for 1 h. The resulting slurry was then sand-milled to make the average particle size D(v, 0.5) less than 4 μm. The slurry was then spray-dried and calcined at 550 °C for 2 h to obtain the catalytic cracking catalyst CAT-1.

[0068] The composition of the catalytic cracking catalyst CAT-1 is as follows: 36 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve Z-1, 4 wt% (dry basis) of GUSY-1 molecular sieve, 14 wt% (dry basis) of titanium- and clay-containing composite binder M-1, 22 wt% (dry basis) of kaolin, 8 wt% of alumina from boehmite, 4 wt% of phosphorus pentoxide from diammonium hydrogen phosphate, and 12 wt% of phosphorus pentoxide from phosphoric acid. The catalyst has a gel solids content of 37%.

[0069] Example 2

[0070] This embodiment provides a catalytic cracking catalyst, the preparation method of which is as follows:

[0071] 1. Preparation of modified ZSM-5 molecular sieve:

[0072] (1) Add 1.5 kg of mesoporous ZSM-5 molecular sieve (dry basis) to 3.5 L of deionized water, stir evenly, then add 20 g of waste liquid containing titanium tetrachloride and 103 g of zirconium sulfate, stir at room temperature (25℃) for 1.5 h to form molecular sieve slurry, dry at 100℃, and calcine at 550℃ for 1.5 h.

[0073] (2) The molecular sieve calcined in step (1) was mixed with 3.5L of deionized water, 97g of phosphoric acid was added, stirred evenly at room temperature (25℃), dried at 100℃, and calcined at 550℃ for 1.5h to obtain titanium, zirconium and phosphorus modified mesoporous ZSM-5 molecular sieve Z-2.

[0074] 2. Preparation of composite adhesives containing titanium and clay:

[0075] Halloysite was pulverized to an average particle size D(v, 0.5) < 4 μm and calcined at 600 °C for 5 hours to obtain calcined material. 1499 g (dry basis) of calcined material was added to 7.3 L of decationized water and stirred. 793 g of waste liquid containing titanium tetrachloride was added, the temperature was raised to 90 °C, and the mixture was stirred for 2 hours. The pH value was adjusted to 2.5 with ammonia water to obtain composite binder M-2 containing titanium and clay.

[0076] The composition of the titanium-clay composite binder M-2 is as follows: 83.3 wt% halloysite roasted material (dry basis), 16.7 wt% titanium from waste liquid containing titanium tetrachloride (calculated as titanium oxide), and the solid content of the titanium-clay composite binder M-2 is 18 wt%.

[0077] 3. Preparation of catalytic cracking catalysts:

[0078] 0.255 kg of kaolin (dry basis), 5 kg of titanium- and clay-containing composite binder M-2, 0.18 kg of alumina sol, and 155.5 mL of rare earth chloride solution were added to a pulping tank and stirred for 0.5 h. Then, 1.14 kg of modified mesoporous ZSM-5 molecular sieve Z-2 (dry basis), 60 g of high-silica ZSM-5 molecular sieve (dry basis), 0.682 kg of phosphoric acid, and 15 g of polyethylene glycol were added and mixed and pulped for 0.5 h. The resulting slurry was then sand-milled to make the average particle size D(v, 0.5) less than 4 μm. After spray drying and calcination at 500 °C for 1 h, catalytic cracking catalyst CAT-2 was obtained.

[0079] The composition of the catalytic cracking catalyst CAT-2 is as follows: 38 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve Z-2, 2 wt% (dry basis) of high-silica ZSM-5 molecular sieve, 30 wt% (dry basis) of titanium- and clay-containing composite binder M-2, 8.5 wt% (dry basis) of kaolin, 6 wt% of alumina from alumina sol, 1.5 wt% of rare earth oxides from rare earth chloride solution, and 14 wt% of phosphorus pentoxide from phosphoric acid. The catalyst has a gel solids content of 32%.

[0080] Example 3

[0081] This embodiment provides a catalytic cracking catalyst, the preparation method of which is as follows:

[0082] 1. Preparation of modified ZSM-5 molecular sieve:

[0083] (1) Under stirring, 792g of waste liquid containing titanium tetrachloride and 113.6g of ferric nitrate were added to 3.6L of deionized water and stirred for 10min. The pH value was adjusted to 1.5 with ammonia water, and then 1.5kg of ordinary ZSM-5 molecular sieve (dry basis) was added. The mixture was stirred at room temperature (25℃) for 1h to form a molecular sieve slurry. The slurry was dried at 100℃ and calcined at 520℃ for 1h.

[0084] (2) The molecular sieve calcined in step (1) was mixed with 3.6L of deionized water, 112g of diammonium hydrogen phosphate was added, stirred evenly at room temperature (25℃), dried at 100℃, and calcined at 520℃ for 1h to obtain titanium, iron and phosphorus modified ZSM-5 molecular sieve Z-3.

[0085] 2. Preparation of composite adhesives containing titanium and clay:

[0086] Kaolin and diatomaceous earth were pulverized to an average particle size D(v, 0.5) < 4 μm and calcined at 850℃ for 2.5 hours to obtain calcined materials. 900 g (dry basis) of calcined kaolin, 100.8 g (dry basis) of calcined diatomaceous earth, and 72 g of carboxymethyl cellulose were added to 2.0 L of decationized water and stirred. 2109 g of waste liquid containing titanium tetrachloride was added, the temperature was raised to 60℃, and the mixture was stirred for 3 hours. The pH value was adjusted to 3.0 with ammonia water to obtain composite binder M-3 containing titanium and clay.

[0087] The composition of the titanium-clay composite binder M-3 is as follows: 50 wt% (dry basis) of kaolin roasting material, 5.6 wt% (dry basis) of diatomaceous earth roasting material, 44.4 wt% (calculated as titanium oxide) of titanium from waste liquid containing titanium tetrachloride, and the solid content of the titanium-clay composite binder M-3 is 30 wt%.

[0088] 3. Preparation of catalytic cracking catalysts:

[0089] (1) Add 0.75 kg of modified ZSM-5 molecular sieve Z-3 (dry basis), 0.21 kg of GUSY-1 molecular sieve (dry basis), 90 g of REHY molecular sieve (dry basis), and 45 g of zirconium oxide to 1.7 L of deionized water, stir, and then perform sand milling to make the average particle size D(v, 0.5) of the mixed molecular sieve slurry less than 4 μm.

[0090] (2) 0.735 kg of kaolin (dry basis), 0.18 kg of diatomaceous earth (dry basis), 0.24 kg of titanium- and clay-containing composite binder M-3 (solid content), 180 g of aluminum sol (alumina), 0.54 kg of boehmite (dry basis), 76.2 g of magnesium chloride, 15 g of lanthanum oxide and 1.6 L of deionized water were added to a pulping tank and pulped for 2 h. Then 150 g of carboxymethyl cellulose and 30 mL of nitric acid were added and stirred for 25 min. The mixture was then aged at 70 °C for 1 h and cooled to 35 °C. The above-mentioned mixed molecular sieve slurry with an average particle size D(v, 0.5) of less than 4 μm was added and pulped for another 0.5 h. The mixture was then homogenized, spray-dried and calcined at 600 °C for 3 h to obtain the catalytic cracking catalyst CAT-3.

[0091] The composition of the catalytic cracking catalyst CAT-3 is as follows: 25 wt% (dry basis) of modified ZSM-5 molecular sieve Z-3, 7 wt% (dry basis) of GUSY-1 molecular sieve, 3 wt% (dry basis) of REHY molecular sieve, 8 wt% (dry basis) of titanium-clay composite binder M-3, 24.5 wt% (dry basis) of kaolin, 6 wt% (dry basis) of diatomaceous earth, 18 wt% of alumina from boehmite, 6 wt% of alumina from alumina sol, 0.5 wt% (based on magnesium oxide) of magnesium chloride, 0.5 wt% of lanthanum oxide, and 1.5 wt% of zirconium oxide. The catalyst has a gel solids content of 36%.

[0092] Example 4

[0093] This embodiment provides a catalytic cracking catalyst, the preparation method of which is as follows:

[0094] 1. Preparation of modified ZSM-5 molecular sieve:

[0095] (1) Add 1.5 kg of mesoporous ZSM-5 molecular sieve (dry basis) to 3.9 L of deionized water, stir evenly, then add 114 g of titanium tetrachloride, adjust the pH value to 1.0 with ammonia water, stir at room temperature (25℃) for 0.5 h to form molecular sieve slurry, dry at 120℃, and calcine at 500℃ for 1 h.

[0096] (2) The molecular sieve calcined in step (1) was mixed with 2.4L of deionized water, 73g of phosphoric acid was added, the mixture was stirred evenly, and then placed in a high pressure vessel and kept at 120℃ for 1h. Then it was dried at 120℃ and calcined at 500℃ for 1h to obtain titanium and phosphorus modified mesoporous ZSM-5 molecular sieve Z-4.

[0097] 2. Preparation of composite adhesives containing titanium and clay:

[0098] Kaolin was pulverized to an average particle size D(v, 0.5) < 4 μm and calcined at 850 °C for 2 hours to obtain calcined material. 1674 g (dry basis) of the calcined material was added to 5.19 L of decationized water and stirred. 299 g of titanium tetrachloride and 9 g of polyethylene glycol were added, the temperature was raised to 85 °C, and the mixture was stirred for 4 hours. The pH value was 3.6, thus obtaining the titanium-clay composite binder M-4.

[0099] The composition of the titanium-clay composite binder M-4 is as follows: 93 wt% (dry basis) of calcined kaolin material, 7 wt% (calculated as titanium oxide) of titanium tetrachloride, and 25 wt% of solid content of composite binder M-4.

[0100] 3. Preparation of catalytic cracking catalysts:

[0101] 0.345 kg of kaolin (dry basis), 4.8 kg of titanium- and clay-containing composite binder M-4, 150 g of silica, 0.8 kg of silica sol, and 1.89 L of deionized water were added to a pulping tank and stirred for 0.5 h. Then, 0.9 kg of modified mesoporous ZSM-5 molecular sieve Z-4 ​​(dry basis) and 15 g of GUSY-1 molecular sieve (dry basis) were added and stirred for 20 minutes. 0.244 kg of phosphoric acid and 15 g of carboxymethyl cellulose were added and mixed and pulped for 1 h. The resulting slurry was then sand-milled to make the average particle size D(v, 0.5) less than 4 μm. After spray drying and calcination at 800 °C for 0.5 h, the catalytic cracking catalyst CAT-4 was obtained.

[0102] The composition of the catalytic cracking catalyst CAT-4 is as follows: 30 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve Z-4, 0.5 wt% (dry basis) of GUSY-1 molecular sieve, 40 wt% (dry basis) of titanium- and clay-containing composite binder M-4, 11.5 wt% (dry basis) of kaolin, 5 wt% of silica, 8 wt% of silica sol, and 5 wt% of phosphorus pentoxide from phosphoric acid. The catalyst has a gel solids content of 32%.

[0103] Comparative Example 1

[0104] This comparative example provides a catalytic cracking catalyst, the preparation method of which is as follows:

[0105] 1. Preparation of modified ZSM-5 molecular sieve:

[0106] (1) Add 1.5 kg of mesoporous ZSM-5 molecular sieve (dry basis) to 3.9 L of deionized water, stir at room temperature (25℃) for 0.5 h to form molecular sieve slurry, dry at 120℃, and calcine at 500℃ for 1 h;

[0107] (2) The molecular sieve calcined in step (1) was mixed with 2.44 L of deionized water, 73 g of phosphoric acid was added, stirred evenly at room temperature (25 °C), dried at 120 °C, and calcined at 500 °C for 1 h to obtain phosphorus-modified mesoporous ZSM-5 molecular sieve DZ-1.

[0108] 2. Preparation of catalytic cracking catalysts:

[0109] 1.08 kg of kaolin (dry basis), 0.24 kg of pseudoboehmite (dry basis), and 2.3 L of deionized water were added to a pulping tank and stirred for 1 h. Then, 32 mL of hydrochloric acid was added, and the mixture was stirred for 0.5 h and aged at 50 °C for 2 h. Next, 1.08 kg of modified mesoporous ZSM-5 molecular sieve DZ-1 (dry basis) and 120 g of GUSY-1 molecular sieve were added and stirred for 15 minutes. Then, 0.223 kg of diammonium hydrogen phosphate and 0.585 kg of phosphoric acid were added, and the mixture was mixed and pulped for 1 h. After homogenization, the mixture was spray-dried and calcined at 550 °C for 2 h to obtain the comparative catalytic cracking catalyst DCAT-1.

[0110] The composition of the catalytic cracking catalyst DCAT-1 is as follows: 36 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve DZ-1, 4 wt% (dry basis) of GUSY-1 molecular sieve, 36 wt% (dry basis) of kaolin, 8 wt% of alumina from boehmite, 4 wt% of phosphorus pentoxide from diammonium hydrogen phosphate, and 12 wt% of phosphorus pentoxide from phosphoric acid. The catalyst has a gel solids content of 37%.

[0111] Comparative Example 2

[0112] This comparative example provides a catalytic cracking catalyst, the preparation method of which is as follows:

[0113] 1. A method for preparing macroporous kaolinite, which is carried out according to the method in Example 8 of the specification CN109694721B. The specific preparation method is as follows:

[0114] Kaolin was calcined at 750℃ for 2 hours to obtain calcined material (referred to as the first calcined material). 1680g (dry basis, the same below) of the calcined material was added to decationized water (pH=3.1, the same below) and stirred to prepare a slurry with a solid content of 25% by weight. 5000g of 1mol / L hydrochloric acid, 1000g of oxalic acid, and 120g of TiCl4 (analytical grade) were added. The mixture was heated to 70℃ and stirred for 1 hour. The mother liquor was then removed by filtration, and the filter cake was dried to obtain the first step product. 1200g of the product was calcined at 750℃ for 2 hours to obtain calcined material (referred to as second calcined material). 1000g (dry basis, the same below) of second calcined material was added to decationized water and stirred to obtain a slurry with a solid content of 25% by weight. 2000g of hydrochloric acid with a concentration of 1mol / L, 500g of oxalic acid, 500g of polyethylene glycol, and 70g of TiCl4 (analytical grade) were added. The temperature was raised to 70℃ and stirred for 1 hour. Then the mother liquor was removed by filtration, and the filter cake was dried to obtain macroporous kaolinite DM-1.

[0115] 2. Preparation of catalytic cracking catalysts:

[0116] 0.66 kg of kaolin (dry basis), 0.42 kg (dry basis) of macroporous kaolinite DM-1, 0.24 kg of pseudoboehmite (dry basis) and 3.17 L of deionized water were added to a pulping tank and stirred for 1 h. Then, 32 mL of hydrochloric acid was added and stirred for 0.5 h, followed by aging at 50 °C for 2 h. Then, 1.08 kg of modified mesoporous ZSM-5 molecular sieve DZ-1 (dry basis) and 120 g (dry basis) of GUSY-1 molecular sieve were added and stirred for 15 minutes. Then, 0.223 kg of diammonium hydrogen phosphate and 0.585 kg of phosphoric acid were added, mixed and pulped for 1 h, homogenized, spray-dried, and calcined at 550 °C for 2 h to obtain the comparative catalytic cracking catalyst DCAT-2.

[0117] The composition of the catalytic cracking catalyst DCAT-2 is as follows: 36 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve DZ-1, 4 wt% (dry basis) of GUSY-1 molecular sieve, 14 wt% (dry basis) of macroporous kaolinite DM-1, 22 wt% (dry basis) of kaolin, 8 wt% of alumina from boehmite, 4 wt% of phosphorus pentoxide from diammonium hydrogen phosphate, and 12 wt% of phosphorus pentoxide from phosphoric acid. The catalyst has a gel solids content of 37%.

[0118] Comparative Example 3

[0119] This comparative example provides a catalytic cracking catalyst, the preparation method of which is as follows:

[0120] 1. Preparation of modified ZSM-5 molecular sieve:

[0121] (1) Add 1.5 kg of mesoporous ZSM-5 molecular sieve (dry basis) to 3.5 L of deionized water, stir at room temperature (25℃) for 1.5 h to form molecular sieve slurry, dry at 100℃, and calcine at 550℃ for 1.5 h;

[0122] (2) The molecular sieve calcined in step (1) was mixed with 3.5L of deionized water, 97g of phosphoric acid was added, stirred evenly at room temperature (25℃), dried at 100℃, and calcined at 550℃ for 1.5h to obtain the phosphorus-modified mesoporous ZSM-5 molecular sieve DZ-2 of this comparative example.

[0123] 2. Preparation of modified halloysite:

[0124] Halloysite was pulverized to an average particle size D(v, 0.5) < 4 μm and calcined at 600 °C for 5 hours to obtain calcined material. 1499 g (dry basis) of the calcined material was added to 5.3 L of decationized water and stirred. 1526 g of hydrochloric acid was added, and the mixture was heated to 90 °C and stirred for 2 hours to obtain the modified halloysite DM-2 of this comparative example. The solid content of the modified halloysite DM-2 was 18 wt%.

[0125] 3. Preparation of catalytic cracking catalysts:

[0126] 0.255 kg of kaolin (dry basis), 5 kg of modified halloysite DM-2, 0.18 kg of alumina sol and 155.5 mL of rare earth chloride solution were added to a pulping tank and stirred for 0.5 h. Then, 1.14 kg of modified mesoporous ZSM-5 molecular sieve DZ-2 (dry basis), 60 g of high-silica ZSM-5 molecular sieve (dry basis) and 0.682 kg of phosphoric acid were added, mixed and pulped for 0.5 h, homogenized, spray-dried and calcined at 500 °C for 1 h to obtain the comparative catalytic cracking catalyst DCAT-3.

[0127] The composition of the catalytic cracking catalyst DCAT-3 is as follows: 38 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve DZ-2, 2 wt% (dry basis) of high-silica ZSM-5 molecular sieve, 30 wt% (dry basis) of modified halloysite DM-2, 8.5 wt% (dry basis) of kaolin, 6 wt% of alumina from alumina sol, 1.5 wt% of rare earth oxides from rare earth chloride solution, and 14 wt% of phosphoric acid pentoxide. The catalyst has a gel solids content of 32%.

[0128] Comparative Example 4

[0129] This comparative example provides a catalytic cracking catalyst, the preparation method of which is as follows:

[0130] 1. Preparation of modified ZSM-5 molecular sieve:

[0131] (1) Under stirring, add 113.6g of ferric nitrate to 4.4L of deionized water, stir for 10min, then add 1.5kg of ordinary ZSM-5 molecular sieve (dry basis), stir at room temperature (25℃) for 1h to form molecular sieve slurry, dry at 100℃, and calcine at 520℃ for 1h.

[0132] (2) The molecular sieve calcined in step (1) was mixed with 3.6L of deionized water, 112g of diammonium hydrogen phosphate was added, stirred evenly at room temperature (25℃), dried at 100℃, and calcined at 520℃ for 1h to obtain the iron and phosphorus modified ZSM-5 molecular sieve DZ-3 of this comparative example.

[0133] 2. Preparation of catalytic cracking catalysts:

[0134] (1) Add 0.75 kg of modified ZSM-5 molecular sieve DZ-3 (dry basis), 0.21 kg of GUSY-1 molecular sieve, and 90 g of REHY molecular sieve (dry basis) to 1.7 L of deionized water and stir evenly to form a mixed molecular sieve slurry.

[0135] (2) 1.05 kg of kaolin (dry basis), 0.18 kg of diatomaceous earth (dry basis), 180 g of alumina sol, 0.54 kg of boehmite (dry basis) and 2.2 L of deionized water were added to a slurry tank and stirred for 2 h. Then 30 mL of nitric acid was added and stirred for 25 min. The mixture was aged at 70 °C for 1 h and cooled to 35 °C. The above mixed molecular sieve slurry was then added and stirred for another 0.5 h. The mixture was then homogenized, spray-dried, and calcined at 600 °C for 3 h to obtain the comparative catalytic cracking catalyst DCAT-4.

[0136] The composition of the catalytic cracking catalyst DCAT-4 is as follows: 25 wt% (dry basis) of modified ZSM-5 molecular sieve DZ-3, 7 wt% (dry basis) of GUSY-1 molecular sieve, 3 wt% (dry basis) of REHY molecular sieve, 35 wt% (dry basis) of kaolin, 6 wt% (dry basis) of diatomaceous earth, 18 wt% of alumina from boehmite, and 6 wt% of alumina from alumina sol. The catalyst has a gel solids content of 36%.

[0137] Comparative Example 5

[0138] This comparative example provides a catalytic cracking catalyst, the preparation method of which is as follows:

[0139] 1. Preparation of modified ZSM-5 molecular sieve:

[0140] 1) Add 1.5 kg of mesoporous ZSM-5 molecular sieve (dry basis) to 3.9 L of deionized water, stir at room temperature (25℃) for 0.5 h to form a molecular sieve slurry, dry at 120℃, and calcine at 500℃ for 1 h;

[0141] (2) The molecular sieve calcined in step (1) was mixed with 2.4L of deionized water, 73g of phosphoric acid was added, the mixture was stirred evenly, and then placed in a high pressure vessel and kept at 120℃ for 1h. Then it was dried at 120℃ and calcined at 500℃ for 1h to obtain phosphorus-modified mesoporous ZSM-5 molecular sieve DZ-4.

[0142] 2. Preparation of catalytic cracking catalysts:

[0143] 1.545 kg of kaolin (dry basis), 150 g of silica, 0.8 kg of silica sol, and 5 L of deionized water were added to a pulping tank and stirred for 0.5 h. Then, 0.9 kg of modified mesoporous ZSM-5 molecular sieve DZ-4 (dry basis) and 15 g of GUSY-1 molecular sieve (dry basis) were added and stirred for 20 minutes. 0.244 kg of phosphoric acid and 15 g of carboxymethyl cellulose were added and mixed and pulped for 1 h. The resulting slurry was then sand-milled to make the average particle size D(v, 0.5) less than 4 μm. After spray drying and calcination at 800 °C for 0.5 h, the comparative catalytic cracking catalyst DCAT-5 was obtained.

[0144] The composition of the catalytic cracking catalyst DCAT-5 is as follows: 30 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve DZ-4, 0.5 wt% (dry basis) of GUSY-1 molecular sieve, 51.5 wt% (dry basis) of kaolin, 5 wt% of silica, 8 wt% of silica sol, and 5 wt% of phosphorus pentoxide from phosphoric acid. The catalyst has a gel solids content of 32%.

[0145] Comparative Example 6

[0146] This comparative example provides a catalytic cracking catalyst, the preparation method of which is as follows:

[0147] (1) A titanium-containing, clay-based, non-calcined comparative binder, the preparation method of which is as follows:

[0148] 1674g (dry basis) of kaolin was crushed without roasting until the average particle size D(v, 0.5) < 4μm. It was then directly added to 4.2L of decationized water and stirred. 332g of waste liquid containing titanium tetrachloride and 18g of polyethylene glycol were added. The mixture was heated to 70℃ and stirred for 1 hour. The pH value was adjusted to 3.5 with ammonia water to obtain the titanium-clay comparative binder DM-3.

[0149] The composition of the titanium- and clay-containing comparative binder DM-3 is as follows: 93 wt% kaolin (dry basis), 7 wt% titanium (calculated as titanium oxide) from waste liquid containing titanium tetrachloride, and the solid content of the comparative binder DM-3 is 25 wt%.

[0150] 2. Preparation of catalytic cracking catalysts:

[0151] 0.66 kg of kaolin (dry basis), 1.68 kg of titanium- and clay-containing composite binder DM-3, 0.24 kg of pseudoboehmite (dry basis), and 2.9 L of deionized water were added to a pulping tank and stirred for 1 h. Then, 32 mL of hydrochloric acid was added, and the mixture was stirred for 0.5 h and aged at 50 °C for 2 h. Next, 1.08 kg of modified mesoporous ZSM-5 molecular sieve DZ-4 (dry basis) and 120 g (dry basis) of GUSY-1 molecular sieve were added and stirred for 15 minutes. Then, 0.223 kg of diammonium hydrogen phosphate, 0.585 kg of phosphoric acid, and 30 g of carboxymethyl cellulose were added and mixed and pulped for 1 h. The resulting slurry was then sand-milled to make the average particle size D(v, 0.5) less than 4 μm. The slurry was then spray-dried and calcined at 550 °C for 2 h to obtain the comparative catalytic cracking catalyst DCAT-6.

[0152] The composition of the catalytic cracking catalyst DCAT-6 is as follows: 36 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve DZ-4, 4 wt% (dry basis) of GUSY-1 molecular sieve, 14 wt% (dry basis) of titanium- and clay-containing comparative binder DM-3, 22 wt% (dry basis) of kaolin, 8 wt% of alumina from boehmite, 4 wt% of phosphorus pentoxide from diammonium hydrogen phosphate, and 12 wt% of phosphorus pentoxide from phosphoric acid. The catalyst has a gelling solids content of 37%.

[0153] Test Example 1

[0154] The anti-wear properties and pore volume of the catalytic cracking catalysts CAT-1, CAT-2, CAT-3, and CAT-4 prepared in Examples 1, 2, 3, and 4, and the comparative catalytic cracking catalysts DCAT-1, DCAT-2, DCAT-3, DCAT-4, DCAT-5, and DCAT-6 prepared in Comparative Examples 1, 2, 3, 4, 5, and 6 were analyzed and tested. The test results are shown in Table 1. Table 1 Performance test results of catalysts CAT-1, CAT-2, CAT-3, CAT-4 and catalysts DCAT-1, DCAT-2, DCAT-3, DCAT-4, DCAT-5, and DCAT-6

[0155] catalyst Wear index, m% / h Pore ​​volume, mL / g CAT-1 0.9 0.41 CAT-2 1.2 0.42 CAT-3 1.5 0.40 CAT-4 1.1 0.43 DCAT-1 4.0 0.36 DCAT-2 3.5 0.39 DCAT-3 2.7 0.38 DCAT-4 3.0 0.37 DCAT-5 13.7 0.34 DCAT-6 3.7 0.35

[0156] The results in Table 1 show that, compared with the comparative catalytic cracking catalysts DCAT-1, DCAT-2, DCAT-3, DCAT-4, and DCAT-6 prepared in Comparative Examples 1, 2, 3, 4, and 6, the catalytic cracking catalysts CAT-1, CAT-2, CAT-3, and CAT-4 prepared in Examples 1, 2, 3, and 4 of this invention have smaller wear indexes, better wear resistance, and larger pore volumes.

[0157] In Table 1, the wear index of DCAT-5 is too high and cannot meet the requirements for catalyst use (generally, the wear index should be below 3.5%). Compared with DCAT-5, catalyst CAT-4 has a low wear index and good anti-wear performance.

[0158] Test Example 2

[0159] This test example is used to evaluate the performance of the catalytic cracking catalysts in Examples 1-3.

[0160] The catalytic cracking catalysts CAT-1, CAT-2, and CAT-3 prepared in Examples 1, 2, and 3, and the comparative catalytic cracking catalysts DCAT-1, DCAT-2, DCAT-3, DCAT-4, and DCAT-6 prepared in Comparative Examples 1, 2, 3, 4, and 6 were subjected to aging treatment at 800°C and 100% water vapor for 17 hours. Then, using wax oil from Lanzhou Petrochemical Company as feedstock, their catalytic cracking reaction performance was evaluated on a heavy oil micro-reaction evaluation device (ACE).

[0161] The evaluation results are shown in Table 2.

[0162] In Table 2, total liquid yield = LPG yield + gasoline yield + diesel yield; coke factor = (100 - conversion rate) × coke yield / conversion rate.

[0163] Table 2. Evaluation results of the reaction selectivity of catalytic cracking catalysts

[0164]

[0165]

[0166] In Table 2, compared with the comparative catalytic cracking catalyst DCAT-1, the catalyst CAT-1 prepared in Example 1 showed a 1.86 percentage point increase in reaction conversion, a 0.86 percentage point decrease in coke yield, a lower coke factor, and a 4.9 percentage point increase in the yield of low-carbon olefins (ethylene + propylene + butene), demonstrating excellent heavy oil conversion, reduced coke production, and increased low-carbon olefin production. Compared with the comparative catalytic cracking catalyst DCAT-6, the catalyst CAT-1 prepared in Example 1 showed the same catalytic performance characteristics. Compared with the comparative catalyst DCAT-3, the catalytic cracking catalyst CAT-2 prepared in Example 2 showed a 1.11 percentage point increase in reaction conversion, a 0.49 percentage point decrease in coke yield, a lower coke factor, and a 2.2 percentage point increase in the yield of low-carbon olefins (ethylene + propylene + butene), demonstrating the same performance characteristics in the catalytic cracking reaction evaluation.

[0167] Table 2 shows that, compared with the comparative catalytic cracking catalysts DCAT-1, DCAT-2, DCAT-3, DCAT-4, and DCAT-6 prepared in Comparative Examples 1, 2, 3, 4, and 6, the catalytic cracking catalysts CAT-1, CAT-2, and CAT-3 of this invention exhibit improved reaction conversion, decreased heavy oil yield, reduced coke factor, and increased yield of low-carbon olefins (ethylene + propylene + butene). This indicates that using the catalytic cracking catalysts provided by this invention promotes efficient conversion of heavy oil, reduces coking tendency, and simultaneously increases the production of low-carbon olefins, thus improving the selectivity of the catalytic cracking reaction.

Claims

1. A catalytic cracking catalyst, comprising, based on 100% by weight of the catalytic cracking catalyst: 15-55% modified ZSM-5 molecular sieve on a dry basis, 0.5-10% Y-type molecular sieve on a dry basis, 0-5% high-silica ZSM-5 molecular sieve on a dry basis, 5-55% clay on a dry basis, 0-25% boehmite on a dry basis, 4-70% titanium-containing composite binder on a dry basis, 0-15% binder on an oxide basis, 0-30% inorganic oxide carrier material on an oxide basis, 0-20% phosphorus on an oxide basis, and 0-5% modified metal compound on an oxide basis; in, The preparation method of the titanium-containing composite adhesive includes the following steps: (1) Mix the calcined clay, water, and titanium tetrachloride solution to obtain a mixture, and calcinate it at 400-900℃ for 0.5-6h; (2) The above mixture is reacted at 40-120℃ for 0.5-6h to obtain the titanium-containing composite adhesive; Based on a dry basis of 100%, the titanium-containing composite adhesive comprises 7-45 wt% titanium as oxide, 0.6-40 wt% aluminum as oxide, and 30-92 wt% silicon as oxide. The preparation method of the modified ZSM-5 molecular sieve includes the following steps: (a) A mixture of ZSM-5 molecular sieve slurry, titanium tetrachloride solution, and one or more compounds selected from iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium is obtained by contacting at 4-150℃ for 10 min-2 h, drying, and calcining. (b) The mixture obtained in step (a) is mixed with a phosphorus-containing compound, contacted at 4-150°C for 10 min-2 h, dried, and calcined to obtain the modified ZSM-5 molecular sieve; the modified ZSM-5 molecular sieve comprises, based on 100% by weight, 0.2-25% titanium (calculated as oxides), 0-5% total of iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium (calculated as oxides), and 0.2-6% phosphorus (calculated as oxides); In the preparation method of the titanium-containing composite binder or the modified ZSM-5 molecular sieve, the titanium tetrachloride solution is titanium tetrachloride waste liquid; the titanium tetrachloride waste liquid is titanium tetrachloride-containing waste liquid generated during the preparation of polypropylene catalyst.

2. The catalytic cracking catalyst according to claim 1, wherein, Based on the weight of the catalytic cracking catalyst as 100%, its composition includes: 20-50% modified ZSM-5 molecular sieve on a dry basis, 2-8% Y-type molecular sieve on a dry basis, 10-50% clay on a dry basis, 3-15% boehmite on a dry basis, 6-40% titanium-containing composite binder on a dry basis, 0-6% binder on an oxide basis, 3-18% phosphorus on an oxide basis, and 0.2-3% modified metal compound on an oxide basis.

3. The catalytic cracking catalyst according to claim 1 or 2, wherein, The titanium-containing composite adhesive has a solid content of 10-45 wt%.

4. The catalytic cracking catalyst according to claim 1 or 2, wherein, Based on a dry basis of 100%, the titanium-containing composite adhesive comprises 7-30 wt% titanium as oxide, 8-40 wt% aluminum as oxide, and 35-70 wt% silicon as oxide.

5. The catalytic cracking catalyst according to claim 1 or 2, wherein, In the preparation method of the titanium-containing composite adhesive, the raw materials mixed in step (1) also include a dispersant; the content of the dispersant is less than 10% based on the dry basis of the titanium-containing composite adhesive being 100%.

6. The catalytic cracking catalyst according to claim 1 or 2, wherein, In the preparation method of the titanium-containing composite binder, the clay includes one or more of kaolin, montmorillonite, diatomite, and sepiolite.

7. The catalytic cracking catalyst according to claim 1 or 2, wherein, In the preparation method of the titanium-containing composite binder, the clay includes halloysite.

8. The catalytic cracking catalyst according to claim 1 or 2, wherein, In the preparation method of the titanium-containing composite binder, the clay includes bentonite and / or hydrous kaolin.

9. The catalytic cracking catalyst according to claim 1 or 2, wherein, The preparation method of the titanium-containing composite adhesive includes the following steps: mixing clay calcined at 550-850℃ for 1-3 hours, water, and waste liquid containing titanium tetrachloride to form a mixture, and heating to 60-120℃ to react for 0.5-3 hours to obtain the titanium-containing composite adhesive.

10. The catalytic cracking catalyst according to claim 1 or 2, wherein, In the preparation method of the titanium-containing composite adhesive, after the reaction in step (2) is completed, the pH value of the reaction system is 0.5-8.

11. The catalytic cracking catalyst according to claim 10, wherein, The pH of the reaction system is adjusted to 0.5-8 using alkaline substances.

12. The catalytic cracking catalyst according to claim 1 or 2, wherein, In step (1), the clay is crushed before or after calcination until the average particle size D(v, 0.5) < 4 μm, and then mixed with water and titanium tetrachloride solution.

13. The catalytic cracking catalyst according to claim 1, wherein, The silicon-aluminum molar ratio of the high-silicon ZSM-5 molecular sieve is above 200.

14. The catalytic cracking catalyst according to claim 1 or 2, wherein, In the preparation method of the modified ZSM-5 molecular sieve, the compounds of iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium are one or more combinations of oxides, chlorides, nitrates, carbonates, sulfates, oxalates, and acetates of iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium.

15. The catalytic cracking catalyst according to claim 14, wherein, In the preparation method of the modified ZSM-5 molecular sieve, the phosphorus-containing compound includes one or more of phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphate, pyrophosphate, polyphosphate, polyphosphate, metaphosphate, and metaphosphate.

16. The catalytic cracking catalyst according to claim 1 or 2, wherein, In the preparation method of the modified ZSM-5 molecular sieve, the calcination temperature in steps (a) and (b) is 450-650℃, and the calcination time is 1h-4h.

17. The catalytic cracking catalyst according to claim 1 or 2, wherein, In the preparation method of the modified ZSM-5 molecular sieve, the titanium tetrachloride solution and / or the compound selected from iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium are adjusted to pH 0.5-8 with an alkaline substance before being mixed with the ZSM-5 molecular sieve slurry.

18. The catalytic cracking catalyst according to claim 1 or 2, wherein, Based on the weight of the modified ZSM-5 molecular sieve as 100%, the modified ZSM-5 molecular sieve comprises 0.2-25% titanium as oxide, 0-5% iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium and yttrium as oxide, and 0.2-6% phosphorus as oxide.

19. The catalytic cracking catalyst according to claim 1 or 2, wherein, The Y-type molecular sieve includes one or more of HY, NH4Y, hydrothermally ultrastable Y molecular sieve, silicon tetrachloride gas-phase ultrastable Y molecular sieve, rare earth-containing Y-type molecular sieve, and phosphorus-modified ultrastable Y molecular sieve; the rare earth-containing Y-type molecular sieve includes one or more of rare earth-modified ultrastable Y molecular sieve and phosphorus and rare earth-modified ultrastable Y molecular sieve.

20. The catalytic cracking catalyst according to claim 1 or 2, wherein, In 5-55% of clay on a dry basis, the clay includes one or more of kaolin, montmorillonite, diatomite, and sepiolite.

21. The catalytic cracking catalyst according to claim 1 or 2, wherein, The clay comprises halloysite in 5-55% by dry weight.

22. The catalytic cracking catalyst according to claim 1 or 2, wherein, The clay comprises 5-55% by dry weight, including bentonite and / or hydrous kaolinite.

23. The catalytic cracking catalyst according to claim 1 or 2, wherein, The inorganic oxide carrier material includes one or more of the following: silica, alumina containing Brønsted acid centers, and aluminosilicate containing Brønsted acid centers.

24. The catalytic cracking catalyst according to claim 1 or 2, wherein, The modified metal compound includes one or more of the following: oxides, chlorides, nitrates, carbonates, sulfates, oxalates, and acetates of iron, zinc, magnesium, calcium, zirconium, lanthanum, cerium, and yttrium.

25. The catalytic cracking catalyst according to claim 1 or 2, wherein, The catalytic cracking catalyst further comprises a pore structure improver; the weight of the pore structure improver is 0.1-10% of the total weight of the catalytic cracking catalyst.

26. The catalytic cracking catalyst according to claim 25, wherein, The pore structure improver includes one or more of 1,3,5-trimethylbenzene, 1,3,5-triisopropylbenzene, methylcellulose, carboxymethylcellulose, polyvinyl alcohol, and polyethylene glycol.

27. A method for preparing the catalytic cracking catalyst according to any one of claims 1-26, comprising the following steps: (1) The modified ZSM-5 molecular sieve, Y-type molecular sieve, clay, pseudoboehmite, titanium-containing composite binder, binder, inorganic oxide carrier material, phosphorus compound, and modified metal compound are mixed and pulped to obtain a slurry; (2) The slurry is spray-dried and shaped, and then calcined and solidified to obtain the catalytic cracking catalyst.

28. The preparation method according to claim 27, wherein, The average particle size D(v, 0.5) of the slurry in step (2) is <4 μm.

29. The preparation method according to claim 28, wherein the ZSM-5 molecular sieve is a mesoporous ZSM-5 molecular sieve.

30. The preparation method according to claim 27, wherein, The pseudoboehmite is added with acid and then aged at 40-90℃ for 0.5-3 hours before being gelled; during the gelling process of the pseudoboehmite with acid, the acid is an inorganic acid.

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