A catalytic cracking aid and a method for its preparation

Abstract

The application provides a catalytic cracking aid and a preparation method thereof. The composition of the catalytic cracking aid comprises: 15-55% ZSM-5 molecular sieve on a dry basis, 0-55% clay on a dry basis, 1-15% alumina nanofiber on a dry basis, 1-10% sheet-shaped aluminum phosphate on a dry basis, 4-70% titanium-containing composite binder on a dry basis, 0-10% binder in terms of oxides, 5-20% phosphorus in terms of oxides and 0-5% modified metal compound in terms of oxides; wherein the preparation of the titanium-containing composite binder utilizes waste liquid containing titanium tetrachloride generated in a polypropylene catalyst preparation process. The catalytic cracking aid can promote the conversion of heavy oil in a catalytic cracking process, increase the total liquid yield (liquefied gas + gasoline + diesel) while increasing the yield of ethylene / propylene and other low-carbon olefins, reduce the coke yield, and has excellent cracking 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 additive, particularly to a catalytic cracking additive used in heavy oil cracking to reduce coke yield, increase total liquid yield and 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, with a 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 titanium tetrachloride waste liquid generated during the preparation of titanium-based polypropylene catalysts contains, in addition to titanium tetrachloride (at least 80%), 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] CN112723430A 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, CN107866211B 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] CN102114429B 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] CN109694721B 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] CN105618107B 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 additives are not involved in reducing coke production, reducing heavy oil yield and increasing total liquid yield in the catalytic cracking process.

[0010] Therefore, in order to solve the problem of treating titanium tetrachloride waste liquid generated during the preparation of polypropylene catalysts, and to address the adverse effects of ZSM-5 molecular sieve additives on heavy oil cracking, such as high heavy oil yield, high coke production, and low total liquid recovery, despite recent additive technologies, there is still a need for new additive 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 additive and its preparation method. This catalytic cracking additive can promote the conversion of heavy oil during catalytic cracking, increase the total liquid yield (LPG + gasoline + diesel) while producing more low-carbon olefins such as ethylene / propylene, and reduce coking. It exhibits excellent cracking reaction selectivity and performance.

[0012] To achieve the above objectives, the present invention provides a catalytic cracking promoter, which, calculated by weight (100%), comprises: 15-55% ZSM-5 molecular sieve (dry basis), 0-55% clay (dry basis), 1-15% alumina nanofibers (dry basis), 1-10% flake aluminum phosphate (dry basis), 4-70% titanium-containing composite binder (dry basis), 0-10% binder (oxide basis), 5-20% phosphorus (oxide basis), and 0-5% modified metal compound (oxide basis); wherein the preparation method of the titanium-containing composite binder includes the following steps:

[0013] (1) Mix calcined clay, water, and titanium tetrachloride solution to obtain a mixture; (2) React the above mixture at 40-120℃ for 0.5-6h to obtain the titanium-containing composite adhesive; the titanium-containing composite adhesive comprises 7-45wt% titanium as oxide, 0.6-40wt% aluminum as oxide, and 30-92wt% silicon as oxide, based on a dry basis of 100%.

[0014] According to a specific embodiment of the present invention, preferably, the catalytic cracking aid, calculated by weight of 100%, comprises: 20-50% ZSM-5 molecular sieve on a dry basis, 10-50% clay on a dry basis, 3-15% alumina nanofibers on a dry basis, 3-8% flake aluminum phosphate on a dry basis, 5-40% titanium-containing composite binder on a dry basis, 6-19% phosphorus on an oxide basis, 3-8% binder on an oxide basis, and 0-3% 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, 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.

[0020] According to a specific embodiment of the present invention, preferably, in the preparation method of the titanium-containing composite adhesive, the titanium tetrachloride solution is pure titanium tetrachloride.

[0021] 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 combinations of kaolin, hydrous kaolin, montmorillonite, diatomite, halloysite, sepiolite, and bentonite, more preferably one or more combinations of kaolin, hydrous kaolin, diatomite, halloysite, and sepiolite.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] According to a specific embodiment of the present invention, preferably, the ZSM-5 molecular sieve, based on oxides, contains 0.2-8% phosphorus and 0-5% a second element, the second element comprising one or more combinations of iron, zinc, magnesium, calcium, titanium, zirconium, lanthanum, cerium, and yttrium; more preferably, the phosphorus is derived from one or more combinations of phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphate, pyrophosphate, polyphosphate, polyphosphate, metaphosphate, and metaphosphate, for example, 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; the iron, zinc, magnesium, calcium, titanium, zirconium, lanthanum, cerium, and yttrium elements are derived from one or more combinations of oxides, chlorides, nitrates, carbonates, sulfates, oxalates, and acetates of iron, zinc, magnesium, calcium, titanium, zirconium, lanthanum, cerium, and yttrium.

[0027] According to a specific embodiment of the present invention, preferably, the clay includes one or more of the following: kaolin, hydrous kaolin, montmorillonite, diatomite, halloysite, sepiolite, and bentonite; more preferably, it is one or more of the following: kaolin, hydrous kaolin, diatomite, halloysite, and sepiolite.

[0028] According to a specific embodiment of the present invention, preferably, the alumina nanofibers have a diameter of 20-50 nm, a length of 0.1-5 μm, and a specific surface area ≥400 m². 2 / g, pore volume ≥1.5cm 3 / g.

[0029] According to a specific embodiment of the present invention, preferably, the method for preparing the flake aluminum phosphate is as follows: aluminum compound and phosphorus compound are reacted at a molar ratio of P / Al = (2.6-3.4):1 at 40℃-90℃ for 0.1-1h, then reacted at 120℃-170℃ for 0.5-3h, dried, and calcined at 400℃-700℃ for 0.5-3h to obtain the flake aluminum phosphate.

[0030] According to a specific embodiment of the present invention, preferably, in the above-mentioned method for preparing flake aluminum phosphate, the aluminum compound includes one or more combinations of alumina, aluminum hydroxide, aluminum sol, and boehmite; the phosphorus compound includes one or more combinations of phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphate, pyrophosphate, polyphosphate, polyphosphate, metaphosphate, and metaphosphate. For example, the phosphorus compound is selected from one or more combinations of phosphoric acid, ammonium phosphate, ammonium hydrogen phosphate, diammonium hydrogen phosphate, phosphorous acid, and ammonium phosphite. More preferably, the boehmite is added to acid and then aged at 40-90°C for 0.5-3 hours for gelation before use; during the acid gelation process of the boehmite, the acid is an inorganic acid, such as one or more combinations of hydrochloric acid, sulfuric acid, and nitric acid.

[0031] According to a specific embodiment of the present invention, preferably, the binder includes one or a combination of two or more of aluminum sol, silica sol, aluminosilicate silica, aluminosilicate phosphate, and acid-soluble boehmite.

[0032] According to a specific embodiment of the present invention, preferably, the acid-soluble boehmite is prepared by adding acid to boehmite, then aging it at 40-90°C for 0.5-3 hours for gelation before use, or by aging it after mixing it with other components; during the acid gelation process of boehmite, the acid is an inorganic acid, such as one or more of hydrochloric acid, sulfuric acid, and nitric acid.

[0033] 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, polyphosphate, polyphosphate, metaphosphate, and metaphosphate. For example, 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.

[0034] 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.

[0035] According to a specific embodiment of the present invention, preferably, the composition of the catalytic cracking promoter 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 promoter.

[0036] 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.

[0037] The additive of the present invention can treat the waste liquid containing titanium tetrachloride generated during the preparation of polypropylene catalyst through the following technical solution: (1) After clay is calcined at high temperature, the crystal structure of it changes. For example, the silicon and aluminum contained in kaolinite are mainly in the 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. Using the above properties of clay and titanium tetrachloride, the waste liquid containing titanium tetrachloride is used to treat the calcined clay. The calcined clay is mixed with water and the waste liquid containing titanium tetrachloride, so that the hydrochloric acid produced by the hydrolysis of titanium tetrachloride reacts with the active aluminum in the calcined clay to prepare a composite binder containing titanium and clay. Because the active aluminum in the clay reacts with the hydrochloric acid produced by the hydrolysis of titanium tetrachloride, the active aluminum is separated from the clay and in the clay In the process of forming medium and large pores, the active aluminum reacting with hydrochloric acid and the fine titanium oxide particles generated by hydrolysis together form a titanium-aluminum mixture together with the above-mentioned medium and large pore clay to form a composite binder containing titanium and clay. This titanium-containing composite binder has the function of a binder and also contains medium and large pore clay components, which is beneficial to improve the pore structure of the catalyst, increase the proportion of medium and large pores in the catalyst, and improve the diffusion performance. (2) 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 rest is mainly hexane, and also contains a small amount of alkoxy titanium complex (about 2-5% by weight), a small amount of lipids) can also act as a template agent between the components of molecular sieve or catalyst. During the high-temperature treatment process of molecular sieve or catalyst preparation, it decomposes and forms pores, improves the pore structure of molecular sieve or catalyst, and improves the diffusion performance. The waste liquid containing titanium tetrachloride is easy to utilize. It does not require the separation of titanium, chlorine and organic matter in the waste liquid containing titanium tetrachloride, and does not increase equipment investment and treatment costs. (3) Alumina nanofibers are long rods and sheets. Aluminum phosphate is sheets. By utilizing their different morphological characteristics, combined with titanium-containing composite binders and pore structure improvers, a smooth pore structure is built in the additive to improve the diffusion performance of the additive.

[0038] The present invention also provides a method for preparing the above-mentioned catalytic cracking aid, which includes the following steps: (1) mixing ZSM-5 molecular sieve, clay, alumina nanofibers, flake aluminum phosphate, titanium-containing composite binder, binder, phosphorus compound, and modified metal compound (preferably with added pore structure improver) to form a slurry; (2) spray drying the slurry to form a shape, and then calcining and curing to obtain the catalytic cracking aid.

[0039] According to a specific embodiment of the present invention, preferably, the ZSM-5 molecular sieve in step (1) is 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 ZSM-5 molecular sieve in step (1) and / or the slurry in step (2) is < 4 μm.

[0040] According to a specific embodiment of the present invention, preferably, the ZSM-5 molecular sieve is a mesoporous ZSM-5 molecular sieve.

[0041] 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.

[0042] The titanium tetrachloride wastewater generated during the preparation of polypropylene catalysts contains approximately 80%-95% titanium tetrachloride (by weight). Discharging this wastewater into the environment would inevitably cause pollution and resource waste. This invention utilizes the titanium tetrachloride wastewater generated during polypropylene catalyst preparation to prepare a titanium- and clay-containing composite binder and catalytic cracking additive. This solves the problem of utilizing the titanium tetrachloride wastewater, avoids environmental pollution, and overcomes the shortcomings of existing technologies. The titanium-containing additive prepared by this invention, when blended with the catalytic cracking catalyst in the heavy oil catalytic cracking process, can promote heavy oil conversion, increase total liquid yield, reduce coking, and achieve high yields of low-carbon olefins. Attached Figure Description

[0043] Figure 1 This is an appearance diagram of the flake aluminum phosphate in Example 1;

[0044] Figure 2 This is a SEM image of the flake aluminum phosphate from Example 1;

[0045] Figure 3 This is a SEM image of alumina nanofibers. Detailed Implementation

[0046] 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.

[0047] The elemental content of the following samples, catalysts, and additives was determined by X-ray fluorescence analysis. The wear index of the catalyst was analyzed using an MS-C / 6 wear index analyzer manufactured by Shenyang Kehui Instrument Manufacturing Co., Ltd. The pore volume of the catalyst was determined using the water droplet method.

[0048] The origin and specifications of the raw materials used are as follows:

[0049] (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), alumina nanofibers ( Figure 3 As shown, the specific surface area is 625 m². 2 / g, pore volume 1.88cm 3 / g, alumina nanofibers are long rods, with a length of 200-600nm: all 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%), boehmite (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), phosphorus-zinc modified ZSM-5 molecular sieve (silicon-to-alumina ratio 31), high-silicon ZSM-5 molecular sieve (silicon-to-alumina ratio 384): all industrial products, sourced from Lanzhou Petrochemical Company Catalyst Plant; LDC-200 catalyst: industrial product, produced by Lanzhou Petrochemical Company Catalyst Plant, treated at 800℃ and 100% steam for 17h.

[0050] (2) Mesoporous ZSM-5 molecular sieve: silica-alumina ratio 30, mesopore volume 0.29 mL / g;

[0051] (3) Diatomaceous earth (loss on ignition 2.6 wt%): Industrial grade;

[0052] (4) Magnesium chloride, phosphoric acid (concentration 85%), diammonium hydrogen phosphate, lanthanum oxide, ferric nitrate (Fe(NO3)3·9H2O), zirconium sulfate, carboxymethyl cellulose, 1,3,5-trimethylbenzene, and polyethylene glycol: all are chemical reagents;

[0053] (5) Hydrochloric acid: 36% concentration, chemical reagent; ammonia: 18% concentration, chemical reagent.

[0054] The spray drying methods for the catalytic cracking additives in Examples 1-4 and Comparative Examples 1-4 used the following process conditions: the temperature of the spray tower furnace was controlled at 450°C, the temperature of the spray tail gas was controlled at 200°C, and the particle size range of the obtained catalytic cracking additives was 65-78 μm.

[0055] Example 1

[0056] This embodiment provides a catalytic cracking aid, the preparation method of which is as follows:

[0057] 1. Preparation of composite adhesives containing titanium and clay:

[0058] 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.

[0059] The composition of the composite binder M-1 containing titanium and clay 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 composite binder M-1.

[0060] 2. Preparation of flake aluminum phosphate:

[0061] 0.14 kg of pseudoboehmite (dry basis) and 2.67 L of deionized water were added to a pulping tank and pulped. Then, 0.955 kg of phosphoric acid was added, and the mixture was reacted at 80 °C for 10 minutes, followed by reaction at 135 °C for 1 hour. After drying, the mixture was calcined at 600 °C for 1.5 hours to obtain flake aluminum phosphate PA1-1, which has the following appearance. Figure 1 As shown, it has a fluffy appearance; SEM image is available in [link to SEM image]. Figure 2 Its shape is flake-like;

[0062] 3. Preparation of catalytic cracking additives:

[0063] 0.6 kg of kaolin (dry basis), 0.24 kg of pseudoboehmite (dry basis), 60 g of flake aluminum phosphate PA1-1 (dry basis), 0.42 kg (solid content) of titanium- and clay-containing composite binder M-1, and 2.86 L of deionized water were added to a pulping tank and pulped 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 zinc-phosphorus modified ZSM-5 molecular sieve (dry basis), 0.12 kg of alumina nanofibers (dry basis), 0.585 kg of phosphoric acid, and 0.223 kg of diammonium hydrogen phosphate were added, 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 550 °C for 2 h, catalytic cracking aid CAT-1 was obtained.

[0064] The composition of catalytic cracking additive CAT-1 is as follows: 36 wt% (dry basis) of phosphorus-zinc modified ZSM-5 molecular sieve, 14 wt% (dry basis) of titanium- and clay-containing composite binder M-1, 4 wt% (dry basis) of alumina nanofibers, 2 wt% (dry basis) of flake aluminum phosphate PA1-1, 20 wt% (dry basis) of kaolin, 8 wt% of alumina from boehmite, 12 wt% of phosphorus pentoxide from phosphoric acid, and 4 wt% of phosphorus pentoxide from diammonium hydrogen phosphate. The gelling solids content of additive CAT-1 is 37%.

[0065] Example 2

[0066] This embodiment provides a catalytic cracking aid, the preparation method of which is as follows:

[0067] 1. Preparation of modified ZSM-5 molecular sieve:

[0068] (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 for 1.5 h to form molecular sieve slurry, dry at 100 °C and calcine at 550 °C for 1.5 h.

[0069] (2) The molecular sieve calcined in step (1) was mixed with 3.5L of deionized water, 97g of phosphoric acid was added, stirred evenly, dried at 100℃, and calcined at 550℃ for 1.5h to obtain titanium, zirconium and phosphorus modified mesoporous ZSM-5 molecular sieve Z-1.

[0070] 2. Preparation of composite adhesives containing titanium and clay:

[0071] 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.

[0072] The composition of the titanium-clay composite binder M-2 is as follows: 83.3 wt% halloysite calcined material (dry basis), 16.7 wt% titanium from waste liquid containing titanium tetrachloride (calculated as titanium oxide), and the solid content of composite binder M-2 is 18 wt%.

[0073] 3. Preparation of catalytic cracking additives:

[0074] 150g of flake aluminum phosphate PA1-1 (dry basis), 60g of alumina nanofibers (dry basis), 5.25kg of titanium- and clay-containing composite binder M-2, 0.18kg of alumina sol, and 155.5mL of rare earth chloride solution were added to a pulping tank and stirred for 0.5h. Then, 1.14kg of modified mesoporous ZSM-5 molecular sieve Z-1 (dry basis), 60g of high-silica ZSM-5 molecular sieve (dry basis), and 0.682kg of phosphoric acid were added and mixed and pulped for 0.5h. The resulting slurry was then sand-milled to make the average particle size D(v, 0.5) less than 4μm. After spray drying and calcination at 500℃ for 1h, catalytic cracking aid CAT-2 was obtained.

[0075] The composition of catalytic cracking additive CAT-2 is as follows: 38 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve Z-1, 2 wt% (dry basis) of high-silica ZSM-5 molecular sieve, 2 wt% (dry basis) of alumina nanofibers, 5 wt% (dry basis) of flake aluminum phosphate PA1-1, 31.5 wt% (dry basis) of titanium- and clay-containing composite binder M-2, 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 gelling solids content of additive CAT-2 is 29%.

[0076] Example 3

[0077] This embodiment provides a catalytic cracking aid, the preparation method of which is as follows:

[0078] 1. Preparation of modified ZSM-5 molecular sieve:

[0079] Under stirring, 113.6 g of ferric nitrate and 112 g of diammonium hydrogen phosphate were added to 3.2 L of deionized water and stirred for 10 min. The pH value was adjusted to 1.5 with ammonia water, and then 1.418 kg of ordinary ZSM-5 molecular sieve (dry basis) was added. The mixture was stirred for 0.5 h to form a molecular sieve slurry. The slurry was dried at 100 °C and calcined at 520 °C for 1.5 h to obtain iron and phosphorus modified ZSM-5 molecular sieve Z-2.

[0080] 2. Preparation of composite adhesives containing titanium and clay:

[0081] 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.

[0082] The composite binder M-3 containing titanium and clay is composed of: 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 composite binder M-3 is 30 wt%.

[0083] 3. Preparation of catalytic cracking additives:

[0084] (1) Add 1.35 kg of modified ZSM-5 molecular sieve Z-2 (dry basis) to 2.1 L of deionized water, stir, and then grind the slurry to make the average particle size D(v, 0.5) of the molecular sieve Z-2 slurry less than 4 μm.

[0085] (2) 0.57 kg kaolin (dry basis), 30 g flake aluminum phosphate PA1-1 (dry basis), 240 g alumina nanofibers (dry basis), 0.8 kg titanium and clay-containing composite binder M-3, 180 g aluminum sol (alumina basis), 76.2 g magnesium chloride, 15 g lanthanum oxide and 1.1 L deionized water were added to a pulping tank and stirred for 2 h. Then, the modified molecular sieve Z-2 slurry with an average particle size D(v, 0.5) less than 4 μm and 0.585 kg phosphoric acid were added. After pulping for another 0.5 h, the mixture was homogenized, spray-dried and calcined at 600 °C for 3 h to obtain catalytic cracking aid CAT-3.

[0086] The composition of catalytic cracking additive CAT-3 is as follows: 45 wt% (dry basis) of modified ZSM-5 molecular sieve Z-2, 8 wt% (dry basis) of alumina nanofibers, 1 wt% (dry basis) of flake aluminum phosphate PA1-1, 8 wt% (dry basis) of composite binder M-3, 19 wt% (dry basis) of kaolin, 6 wt% (dry basis) of alumina from alumina sol, 0.5 wt% (calculated as magnesium oxide) of magnesium chloride, 0.5 wt% (calculated as lanthanum oxide), and 12 wt% (calculated as phosphorus pentoxide) of phosphoric acid. The gelling solids content of additive CAT-3 is 36%.

[0087] Example 4

[0088] This embodiment provides a catalytic cracking aid, the preparation method of which is as follows:

[0089] 1. Preparation of modified ZSM-5 molecular sieve:

[0090] (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 for 0.5 h to form molecular sieve slurry, dry at 120 °C, and calcine at 500 °C for 1 h.

[0091] (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-3.

[0092] 2. Preparation of composite adhesives containing titanium and clay:

[0093] 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.

[0094] 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.

[0095] 3. Preparation of catalytic cracking additives:

[0096] 0.24 kg of kaolin (dry basis), 0.36 kg of halloysite (dry basis), 4.8 kg of titanium- and clay-containing composite binder M-4, 0.4 kg of silica sol, and 1.3 L of deionized water were added to a pulping tank and stirred for 1 h. Then, 0.6 kg of modified mesoporous ZSM-5 molecular sieve Z-3 (dry basis), 240 g of flake aluminum phosphate PA1-1 (dry basis), and 90 g of alumina nanofibers (dry basis) were added and stirred for 30 minutes. 0.244 kg of phosphoric acid and 15 g of 1,3,5-trimethylbenzene 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 700 °C for 2 h, catalytic cracking aid CAT-4 was obtained.

[0097] The composition of catalytic cracking additive CAT-4 is as follows: 20 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve Z-3, 3 wt% (dry basis) of alumina nanofibers, 8 wt% (dry basis) of flake aluminum phosphate PA1-1, 40 wt% (dry basis) of titanium- and clay-containing composite binder M-4, 8 wt% (dry basis) of kaolin, 12 wt% (dry basis) of halloysite, 4 wt% (dry basis) of silica sol, and 5 wt% (dry basis) of phosphoric acid. The gelling solids content of additive CAT-4 is 35%.

[0098] Comparative Example 1

[0099] This comparative example provides a catalytic cracking aid, the preparation method of which is as follows:

[0100] 1.14 kg of kaolin (dry basis), 0.3 kg of pseudoboehmite (dry basis), and 4.0 L of deionized water were added to a pulping tank and pulped for 1 h. Then, 40 mL of hydrochloric acid was added, and the mixture was stirred for 0.5 h. The mixture was then aged at 50 °C for 2 h. Next, 1.08 kg of zinc-phosphate modified ZSM-5 molecular sieve (dry basis), 0.585 kg of phosphoric acid, and 0.223 kg of diammonium hydrogen phosphate were added, mixed, pulped for 1 h, homogenized, spray-dried, and calcined at 550 °C for 2 h to obtain the comparative catalytic cracking aid DCAT-1.

[0101] The composition of catalytic cracking additive DCAT-1 is as follows: 36 wt% (dry basis) of phosphorus-zinc modified ZSM-5 molecular sieve, 38 wt% (dry basis) of kaolin, 10 wt% of alumina from boehmite, 12 wt% of phosphorus pentoxide from phosphoric acid, and 4 wt% of phosphorus pentoxide from diammonium hydrogen phosphate. The gelling solids content of additive DCAT-1 is 37%.

[0102] Comparative Example 2

[0103] This comparative example provides a catalytic cracking aid, the preparation method of which is as follows:

[0104] 1. Preparation of modified ZSM-5 molecular sieve:

[0105] (1) Add 1.5 kg of mesoporous ZSM-5 molecular sieve (dry basis) to 3.5 L of deionized water, stir for 1.5 h to form molecular sieve slurry, dry at 100 °C and calcine at 550 °C for 1.5 h;

[0106] (2) The molecular sieve calcined in step (1) was mixed with 3.5L of deionized water, 97g of phosphoric acid was added, the mixture was stirred evenly, dried at 100℃, and calcined at 550℃ for 1.5h to obtain phosphorus-modified mesoporous ZSM-5 molecular sieve DZ-1.

[0107] 2. Preparation of catalytic cracking additives:

[0108] 1.155 kg halloysite (dry basis), 0.18 kg aluminum sol (alumina basis), 6.0 L deionized water and 155.5 mL rare earth chloride solution were added to a pulping tank and stirred for 0.5 h. Then, 1.14 kg modified mesoporous ZSM-5 molecular sieve DZ-1 (dry basis), 60 g high silica ZSM-5 molecular sieve (dry basis) and 0.682 kg phosphoric acid were added and mixed and pulped for 0.5 h. The resulting slurry was homogenized, spray-dried and calcined at 500 °C for 1 h to obtain the comparative additive DCAT-2.

[0109] The composition of catalytic cracking additive DCAT-2 is as follows: 38 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve DZ-1, 2 wt% (dry basis) of high-silica ZSM-5 molecular sieve, 38.5 wt% (dry basis) of halloysite, 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 gelling solids content of additive DCAT-2 is 29%.

[0110] Comparative Example 3

[0111] This comparative example provides a catalytic cracking aid, the preparation method of which is as follows:

[0112] (1) Add 1.35 kg of modified ZSM-5 molecular sieve Z-2 (dry basis) to 2.1 L of deionized water and stir to form molecular sieve Z-2 slurry;

[0113] (2) 1.02 kg of kaolin (dry basis), 240 g of aluminum sol (alumina basis), 76.2 g of magnesium chloride, 15 g of lanthanum oxide and 1.59 L of deionized water were added to a pulping tank and stirred for 2 h. Then the above molecular sieve Z-2 slurry and 0.585 kg of phosphoric acid were added and pulped for another 0.5 h. After homogenization, spray drying and calcination at 600 °C for 3 h were obtained to obtain the comparative additive DCAT-3.

[0114] The composition of catalytic cracking additive DCAT-3 is as follows: 45 wt% (dry basis) of modified ZSM-5 molecular sieve Z-2, 34 wt% (dry basis) of kaolin, 8 wt% of alumina from alumina sol, 0.5 wt% (based on magnesium oxide) of magnesium chloride, 0.5 wt% of lanthanum oxide, and 12 wt% of phosphorus pentoxide from phosphoric acid. The gelling solids content of additive DCAT-3 is 36%.

[0115] Comparative Example 4

[0116] This comparative example provides a catalytic cracking aid, the preparation method of which is as follows:

[0117] 1. A titanium-containing, clay-based, non-calcined comparative binder, the preparation method of which is as follows:

[0118] 1674g (dry basis) of kaolin was pulverized to an average particle size D(v, 0.5) < 4μm. Without calcination, 4.2L of decationized water was added and stirred. 299g of titanium tetrachloride and 9g of polyethylene glycol were added. The mixture was heated to 85℃ and stirred for 4 hours. The pH value was adjusted to 3.5 with ammonia water to obtain the titanium- and clay-containing comparative composite binder DM-1.

[0119] The composition of the titanium- and clay-containing comparative composite binder DM-1 is as follows: 93 wt% kaolin roasted material (dry basis), 7 wt% titanium from titanium tetrachloride (calculated as titanium oxide), and the solid content of the comparative composite binder DM-1 is 25 wt%.

[0120] 2. Preparation of catalytic cracking additives:

[0121] 0.24 kg of kaolin (dry basis), 0.36 kg of halloysite (dry basis), 4.8 kg of titanium- and clay-containing comparative composite binder DM-1, 0.4 kg of silica sol, and 1.3 L of deionized water were added to a pulping tank and stirred for 1 h. Then, 0.6 kg of modified mesoporous ZSM-5 molecular sieve Z-3 (dry basis), 240 g of flake aluminum phosphate PA1-1 (dry basis), and 90 g of alumina nanofibers (dry basis) were added and stirred for 30 minutes. 0.244 kg of phosphoric acid and 15 g of 1,3,5-trimethylbenzene 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 700 °C for 2 h, catalytic cracking aid DCAT-4 was obtained.

[0122] The composition of catalytic cracking additive DCAT-4 is as follows: 20 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve Z-3, 3 wt% (dry basis) of alumina nanofibers, 8 wt% (dry basis) of flake aluminum phosphate PA1-1, 40 wt% (dry basis) of titanium- and clay-containing comparative composite binder DM-1, 8 wt% (dry basis) of kaolin, 12 wt% (dry basis) of halloysite, 4 wt% (dry basis) of silica sol, and 5 wt% (dry basis) of phosphoric acid. The gelling solids content of additive DCAT-4 is 35%.

[0123] Test Example 1

[0124] The anti-wear properties and pore volume of the catalytic cracking aids CAT-1, CAT-2, CAT-3, and CAT-4 prepared in Examples 1-4, and the comparative catalytic cracking aids DCAT-1, DCAT-2, and DCAT-3 prepared in Comparative Examples 1-4 were analyzed and tested. The test results are shown in Table 1.

[0125] Table 1. Performance test results of catalytic cracking additives CAT-1, CAT-2, CAT-3, etc., and catalytic cracking additives DCAT-1, DCAT-2, DCAT-3, etc.

[0126] Catalytic cracking aids Wear index, m% / h Pore ​​volume, mL / g CAT-1 1.1 0.39 CAT-2 1.2 0.44 CAT-3 1.8 0.40 CAT-4 0.9 0.40 DCAT-1 3.0 0.24 DCAT-2 3.6 0.36 DCAT-3 4.7 0.30 DCAT-4 10.9 0.36

[0127] The results in Table 1 show that, compared with the comparative catalytic cracking aids DCAT-1, DCAT-2, DCAT-3, and DCAT-4 prepared in Comparative Examples 1, 2, 3, and 4, the catalytic cracking aids CAT-1, CAT-2, CAT-3, and CAT-4 prepared in Examples 1, 2, 3, and 4 of this invention have a smaller wear index, better wear resistance, and larger pore volume.

[0128] In Table 1, the wear index of DCAT-4 is too high and cannot meet the requirements for use as a catalytic cracking additive (generally, the wear index should be below 3.5%). Compared with DCAT-4, the additive CAT-4 has a low wear index and good anti-wear properties.

[0129] Test Example 2

[0130] This test example is used to evaluate the performance of the catalytic cracking aids in Examples 1-3.

[0131] The industrial catalyst with industrial grade LDC-200QH was mixed with the catalytic cracking aids CAT-1, CAT-2, and CAT-3 prepared in Examples 1, 2, and 3, and the comparative catalytic cracking aids DCAT-1, DCAT-2, and DCAT-3 prepared in Comparative Examples 1, 2, and 3 at a weight ratio of 9:1 to obtain 6 catalyst mixtures. After the 6 catalyst mixtures were aged at 800°C and 100% water vapor for 17 hours, the catalytic cracking reaction performance was evaluated on a heavy oil microreactor (ACE) device.

[0132] The evaluation results are shown in Table 2.

[0133] In Table 2, total liquid yield = LPG yield + gasoline yield + diesel yield; coke factor = (100 - conversion rate) × coke yield / conversion rate.

[0134] Table 2. Evaluation results of the selectivity of catalytic cracking reaction for catalytic cracking additives.

[0135]

[0136]

[0137] In Table 2, compared with the comparative additive DCAT-1, the additive CAT-1 prepared in Example 1, when mixed with the base agent LDC-200QH industrial catalyst at a weight ratio of 9:1, showed a 0.66 percentage point increase in catalytic cracking conversion rate, a 1.26 percentage point increase in total liquid yield (LPG + gasoline + diesel), a 0.62 percentage point decrease in coke yield, a decrease in coke factor, and a 2.3 percentage point increase in low-carbon olefin (ethylene + propylene + butene) yield, demonstrating excellent heavy oil conversion, reduced coking, and increased low-carbon olefin production. Compared with the comparative additive DCAT-2, the additive CAT-2 prepared in Example 2, when mixed with the base agent LDC-200QH industrial catalyst at a weight ratio of 9:1, showed a 1.04 percentage point increase in catalytic cracking conversion rate, a 1.26 percentage point increase in total liquid yield (LPG + gasoline + diesel), and a 0.62 percentage point decrease in coke yield, a decrease in coke factor, and a 2.3 percentage point increase in low-carbon olefin (ethylene + propylene + butene) yield, demonstrating excellent heavy oil conversion, reduced coking, and increased low-carbon olefin production. The yield of catalytic cracking (ethylene + propylene + butene) increased by 1.36 percentage points, while the coke yield decreased by 0.68 percentage points, the coke factor decreased, and the yield of low-carbon olefins (ethylene + propylene + butene) increased by 3.13 percentage points, demonstrating excellent heavy oil conversion, reduced coking, and increased low-carbon olefin production. Compared with the comparative additive DCAT-3, the additive CAT-3 prepared in Example 3, when mixed with the base agent LDC-200QH industrial catalyst at a weight ratio of 9:1, increased the catalytic cracking reaction conversion rate by 0.95 percentage points, increased the total liquid yield (liquefied petroleum gas + gasoline + diesel) by 0.99 percentage points, decreased the coke yield by 0.45 percentage points, reduced the coke factor, and increased the yield of low-carbon olefins (ethylene + propylene + butene) by 2.8 percentage points, also demonstrating excellent heavy oil conversion, reduced coking, and increased low-carbon olefin production. Furthermore, the additive is easy to use, requires a small dosage, and has a rapid effect.

[0138] Table 2 shows that, compared with the comparative additives DCAT-1, DCAT-2, and DCAT-3, adding the catalytic cracking additives CAT-1, CAT-2, and CAT-3 of this invention to the LDC-200QH industrial catalyst resulted in increased catalytic cracking conversion, decreased heavy oil yield, decreased coke factor, increased total liquid yield, and increased yield of low-carbon olefins (ethylene + propylene + butene). This indicates that using the additives provided by this invention promotes efficient heavy oil conversion, 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 additive, comprising, based on 100% by weight of the catalytic cracking additive, the following components: 15-55% ZSM-5 molecular sieve on a dry basis, 0-55% clay on a dry basis, 1-15% alumina nanofibers on a dry basis, 1-10% flake aluminum phosphate on a dry basis, 4-70% titanium-containing composite binder on a dry basis, 0-10% binder on an oxide basis, 5-20% 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 titanium tetrachloride solution is titanium tetrachloride waste liquid; the titanium tetrachloride waste liquid is a titanium tetrachloride-containing waste liquid generated during the preparation of polypropylene catalyst.

2. The catalytic cracking aid according to claim 1, wherein, Based on the weight of the catalytic cracking aid being 100%, its composition includes: 20-50% ZSM-5 molecular sieve on a dry basis, 10-50% clay on a dry basis, 3-15% alumina nanofibers on a dry basis, 3-8% flake aluminum phosphate on a dry basis, 5-40% titanium-containing composite binder on a dry basis, 6-19% phosphorus on an oxide basis, 3-8% binder on an oxide basis, and 0-3% modified metal compound on an oxide basis.

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

4. The catalytic cracking aid according to claim 3, 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 aid 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 aid 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 aid 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 aid 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 aid 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 aid 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 aid according to claim 10, wherein, The pH of the reaction system is adjusted to 0.5-8 using alkaline substances.

12. The catalytic cracking aid 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 aid according to claim 1 or 2, wherein, Based on oxides, the ZSM-5 molecular sieve contains 0.2-8% phosphorus and 0-5% a second element, which includes one or more of the elements iron, zinc, magnesium, calcium, titanium, zirconium, lanthanum, cerium, and yttrium.

14. The catalytic cracking aid according to claim 1 or 2, wherein, In clay comprising 0-55% on a dry basis, the clay includes one or more of kaolin, montmorillonite, diatomite, and sepiolite.

15. The catalytic cracking aid according to claim 1 or 2, wherein, In clay comprising 0-55% on a dry basis, the clay includes halloysite.

16. The catalytic cracking aid according to claim 1 or 2, wherein, In clays comprising 0-55% on a dry basis, the clays include bentonite and / or hydrous kaolinite.

17. The catalytic cracking aid according to claim 1 or 2, wherein, The alumina nanofibers have a diameter of 20-50 nm, a length of 0.1-5 μm, and a specific surface area ≥400 m². 2 / g, pore volume ≥1.5cm 3 / g.

18. The catalytic cracking aid according to claim 1 or 2, wherein, The method for preparing the flake aluminum phosphate is as follows: aluminum compounds and phosphorus compounds are reacted at a molar ratio of P / Al = (2.6-3.4):1 at 40℃-90℃ for 0.1-1h, then reacted at 120℃-170℃ for 0.5-3h, dried, and calcined at 400℃-700℃ for 0.5-3h to obtain the flake aluminum phosphate.

19. The catalytic cracking aid according to claim 18, wherein, The aluminum compounds include one or more of aluminum oxide, aluminum hydroxide, aluminum sol, and boehmite. The phosphorus compounds include one or more of the following: phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphate, pyrophosphate, polyphosphate, polyphosphate, metaphosphate, and metaphosphate.

20. The catalytic cracking aid according to claim 1 or 2, wherein, The binder includes one or more of the following: aluminum sol, silica sol, silica-alumina glue, phospho-alumina glue, and acid-soluble boehmite.

21. The catalytic cracking aid according to claim 20, wherein, The acid-soluble boehmite is prepared by adding acid to boehmite, then aging it at 40-90℃ for 0.5-3 hours to achieve gelation before use; during the acid gelation process of the boehmite, the acid is an inorganic acid.

22. The catalytic cracking aid 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.

23. The catalytic cracking aid according to claim 1 or 2, wherein, The composition of the catalytic cracking promoter also includes a pore structure improver; the weight of the pore structure improver is 0.1-10% of the total weight of the catalytic cracking promoter.

24. The catalytic cracking aid according to claim 23, 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.

25. A method for preparing the catalytic cracking additive according to any one of claims 1-24, comprising the following steps: (1) ZSM-5 molecular sieve, clay, alumina nanofibers, flake aluminum phosphate, titanium-containing composite binder, binder, 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 cured to obtain the catalytic cracking aid.

26. The preparation method according to claim 25, wherein, The ZSM-5 molecular sieve is a mesoporous ZSM-5 molecular sieve.

27. The preparation method according to claim 26, wherein, The average particle size D(v, 0.5) of the slurry in step (2) is <4 μm.

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