An anti-metal contamination catalytic cracking aid and a preparation method thereof

Abstract

The application provides an anti-metal contamination catalytic cracking aid and a preparation method thereof. The composition of the catalytic cracking aid comprises: 4-40% of phosphorus in terms of P2O5, 1-15% of alumina nanofiber in dry basis, 1-10% of flaky aluminum phosphate in dry basis, 2-50% of titanium modified clay, 0-30% of aluminum compound in terms of oxide, 0-20% of alkaline earth metal in terms of oxide, 0-70% of clay in dry basis, and 0-10% of inorganic carrier material in terms of oxide; wherein the titanium modified clay is prepared by using waste liquid containing titanium tetrachloride generated in a polypropylene catalyst preparation process. The anti-metal contamination catalytic cracking aid has good anti-metal contamination capacity, cracking reaction selectivity and use performance, and can promote efficient conversion of heavy oil and reduce coke formation.

Description

Technical Field

[0001] This invention belongs to the field of refining catalysts and additives, and relates to a catalytic cracking additive, particularly a catalytic cracking additive resistant to iron, nickel, and vanadium, especially iron contamination, 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] Catalytic cracking feedstocks contain metallic contaminants such as iron, nickel, and vanadium. These contaminants deposit on the catalyst during catalytic cracking, causing catalyst poisoning and deactivation. This leads to decreased selectivity in the catalytic cracking reaction, increased yields of coke and dry gas, and decreased yields of target products such as gasoline and diesel, affecting the stable operation of the catalytic cracking unit and the refinery's economic efficiency. As FCC feedstocks become increasingly heavier and of lower quality, the impact of metal poisoning on FCC catalysts is becoming more severe. Iron can deposit on the catalyst surface, forming low-melting-point eutectic compounds with sodium and silicon in the catalyst. This blocks the catalyst pores, affecting the diffusion and mass transfer of oil and gas molecules within the catalyst pores, reducing the accessibility of the catalyst's active centers, and thus decreasing the catalyst's heavy oil conversion capacity and the selectivity of the catalytic cracking reaction. Vanadium in the feedstock will form vanadate under FCC conditions, causing dealuminization and structural collapse of the molecular sieve framework, ultimately leading to the deactivation of the molecular sieve and the catalyst. This will also reduce the catalyst's heavy oil conversion capacity and the selectivity of the catalytic cracking reaction. Nickel in crude oil deposits on the catalyst. During the catalytic cracking reaction, nickel has strong dehydrogenation activity, increasing hydrogen yield and promoting the coking reaction of unsaturated hydrocarbons, which blocks the catalyst pores, reduces the catalyst's specific surface area, and worsens the selectivity of the catalytic cracking reaction.

[0004] To address the adverse effects of metal contaminants such as iron, nickel, and vanadium on catalysts, current technologies mainly focus on three aspects: improving the resistance of catalytic cracking catalysts to metal contamination, using catalytic cracking promoters, and using metal passivators. Among these, the use of catalytic cracking promoters and metal passivators is convenient to use, eliminates the need to replace all catalysts in the catalytic cracking unit to achieve a specific reaction target, and is characterized by low dosage and rapid effectiveness.

[0005] Regarding catalysts for resisting metal contamination, CN1057022C discloses a zeolite catalyst with a chemically modified matrix and its preparation method. The catalyst matrix is ​​a novel component composed of alkaline earth metal titanates and phosphorus-containing γ-Al₂O₃. The catalyst consists of 10-60 wt% of one of HY, REY, or USY zeolites, 5-40 wt% of natural or synthetic kaolinite, 5-40 wt% of 0.1-4.0 wt% of high-temperature resistant phosphorus-containing γ-Al₂O₃, and 1-30 wt% of alkaline earth metal titanates selected from Ba, Sr, or Mg. This catalyst exhibits high activity, high resistance to carbon, and strong resistance to heavy metal contamination by nickel and vanadium.

[0006] CN104014361B discloses a catalytic cracking catalyst and its preparation method. The catalyst comprises 1-60 wt% modified biporous alumina, 10-70 wt% molecular sieve with a FAU structure, 1-60 wt% binder, and 5-70 wt% clay. Based on the weight of the modified biporous alumina, it contains 0.05-1 wt% rare earth elements (based on RE₂O₃) and 0.5-10 wt% silicon (based on SiO₂). The modified biporous alumina has a γ-alumina crystal structure, with accessible pore sizes of 4-9.5 nm for smaller pores and 12-25 nm for larger pores, and a specific surface area of ​​250-500 m². 2 / g, pore volume 0.6-1.8cm³ 3 / g. This catalyst can improve gasoline quality and increase liquid product yield, and has strong heavy oil cracking capability under metal contamination conditions.

[0007] CN103769192B discloses a catalytic cracking catalyst and its preparation method. The catalyst contains a biporous silica-alumina material and a molecular sieve. The smaller pore of the biporous silica-alumina material has a visible pore size of 2-10 nm, and the larger pore has a visible pore size of 10-25 nm. Based on the total catalyst volume, the content of the biporous silica-alumina material is 1-52% by weight, the clay content is 9-60%, the phosphorus content (based on P2O5) is 0-8%, the rare earth metal content (based on RE2O3) is 0-3%, the binder content is 19-70%, and the Y-type molecular sieve content is 20-70%. This catalyst exhibits strong resistance to metal contamination, strong heavy oil cracking capacity, high liquid yield, and can improve the quality of gasoline in the cracking products.

[0008] Regarding anti-metal contamination additives, CN100478420C discloses a catalytic cracking additive and its preparation method. This additive contains alumina and molecular sieves, with or without clay. The alumina is n-alumina and / or X-alumina, or a mixture of n-alumina and / or X-alumina with γ-alumina. The additive also contains phosphorus and alkaline earth metals. Based on the additive weight, the content of n-alumina and / or X-alumina is 0.5-50 wt%, the content of γ-alumina is 0-50 wt%, the content of molecular sieve is 0.5-20 wt%, the content of clay is 0-75 wt%, the phosphorus content (based on P2O5) is 0.1-4 wt%, and the alkaline earth metal content (based on oxides) is 0.1-4 wt%. The molecular sieve is Y-type zeolite. This additive has strong resistance to heavy metal contamination and can improve the quality of gasoline in cracking products.

[0009] CN101439303A discloses a heavy hydrocarbon oil catalytic cracking additive and its preparation method, comprising the following components (wt%): Al2O3 10-65%, P (based on elemental P) 2-13%, SiO2 1-15%, and clay 10-65%. The preparation method includes: a. Preparation of aluminum phosphate colloid: dissolving a phosphorus source compound and hydrated alumina separately in deionized water according to a P:Al2O3 molar ratio of 0.5-5:1, and preparing an aluminum phosphate colloid with a solid content of 20-40 wt%; stirring and dissolving at 20℃-60℃ for 1-5 hours; obtaining the aluminum phosphate colloid for later use; b. Preparation of aluminum phosphate colloid: adding water glass to the dissolved aluminum phosphate colloid, wherein the amount of water glass added is by weight percentage. The ratio of SiO2:Al2O3 is 0.01-1.5:1. Under stirring, the mixture is aged at 20℃-80℃ for 1-3 hours to obtain a silica-alumina phosphate gel for later use. c. Mixing and pulping: Clay is added to the silica-alumina phosphate gel, with the amount of clay added ensuring that the clay content in the final additive is 10-65 wt%. The mixture is then mixed and pulped for 1-3 hours. d. Spray molding; e. Washing and drying: The filtrate is washed with deionized water until the pH value is between 6 and 7, and then dried at 80-120℃. This additive has a strong resistance to heavy metal contamination and improves the selectivity of heavy hydrocarbon oil cracking reactions. However, this patent does not provide information on the additive's resistance to heavy metal contamination, nor does it specify which heavy metal contamination the additive resists. The presence of silica is detrimental to the resistance to iron contamination. The additive contains SiO2 provided by water glass, while iron oxide, sodium, and silica form a low-melting-point eutectic with a melting point below 500℃. Under reaction-regeneration temperature conditions, it has strong fluidity, which blocks the catalyst pores, prevents the diffusion of macromolecules, affects the accessibility of the catalyst active center, and reduces the heavy oil conversion capacity (Reference 1: Shi Lei, Bi Lintian, Yao Yuan. The effect of iron on catalytic cracking catalyst [J]. Qilu Petrochemical, 2012, 40(1): 50-53; Reference 2: Bai Rui. Study on the iron migration law of catalytic cracking reactor bed and industrial application of new iron-resistant catalyst [J]. Petroleum Refining and Chemical Industry, 2022, 53(4): 38-42).

[0010] Regarding anti-metal contamination passivating agents, CN88102585A discloses a method for suppressing the poisoning effect of contaminating metals on cracking catalysts during fluidized catalytic cracking. This method involves depositing a small amount of bismuth-containing passivating agent onto the catalyst to suppress the poisoning effect of contaminating metals such as nickel, vanadium, and iron on the cracking catalyst during fluidized catalytic cracking with hydrocarbon feed containing contaminating metals. Ideally, the weight ratio of bismuth to nickel equivalent (nickel + 0.2 vanadium and 0.1 iron) is approximately 0.01:1 to 1:1. The passivating agent may also contain mixtures of bismuth and antimony, as well as compounds of bismuth and tin.

[0011] CN100540141C discloses a catalytic cracking metal passivator and its preparation method, which provides boron-containing compounds and compounds containing both boron and phosphorus as catalytic cracking metal passivators. This passivator exhibits a significant passivation effect on nickel on the catalytic cracking catalyst, resulting in a marked improvement in the distribution of reaction products. The yield of the ideal product, gasoline, increases by 2.5–4 percentage points, while the yields of the non-ideal products, coke and hydrogen, decrease, with the hydrogen yield decreasing by 20–40%. However, if boron migrates onto the catalyst, even a small amount can disrupt the structure of the active molecular sieve component in the catalyst, leading to a decrease in the catalyst's cracking activity and conversion rate.

[0012] CN1133717C discloses a water-soluble catalytic cracking (FCC) metal passivator and its preparation method. This passivator is effective against heavy metal contamination on catalytic cracking catalysts, especially nickel, iron, vanadium, and sodium. The agent uses antimony, aluminum, and rare earth metal elements lanthanum (or cerium) as the main active components. After the compounds of these metal elements react with organic carboxylic acids, they are mixed to form highly stable compounds. It has the characteristics of high efficiency, low toxicity, stable properties (does not decompose below 300℃), convenient use, and water miscibility. It can passivate the contamination of catalysts by nickel, iron, vanadium, and sodium, improve the yield of gasoline and light oil, reduce hydrogen yield and hydrogen / methane ratio, improve product selectivity, and enhance catalyst activity.

[0013] In existing technologies, anti-metal contamination catalytic cracking catalysts generally contain metal trapping components, such as rare earth oxides and alkaline earth metals, in their formulation design. They also employ porous active support materials or modify catalyst preparation techniques to increase the pore volume and the proportion of mesopores and macropores, thereby passivating heavy metals, reducing the adverse effects of metal contamination on the catalyst, and improving the catalyst's resistance to metal contamination. However, the rare earth oxides and alkaline earth metals used for metal trapping in the catalyst can transfer to the molecular sieve during use. Rare earths can increase the acid density and coke yield of the molecular sieve catalyst, while excessive alkaline earth metals can neutralize the acid active sites of the molecular sieve, reducing catalyst activity. Therefore, the content of rare earth and alkaline earth metals used for metal contamination resistance in catalytic cracking catalysts is usually low, affecting their anti-metal contamination effect.

[0014] In existing technologies, passivating agents for resisting metal contamination are liquid-phase and generally contain organic solvents and metal trapping components, such as Sb, rare earth oxides, and alkaline earth metals. During catalytic cracking, the passivating agent is added to the reactor along with the feedstock. The passivating agent droplets deposit on the surface of catalyst microspheres and interact with harmful contaminating metal components, thereby passivating heavy metals, reducing the adverse effects of metal contamination on the catalyst, and improving the catalyst's resistance to metal contamination. However, the metal passivating agents with industrial application value are mainly organometallic passivating agents such as antimony-based, bismuth-based, and tin-based agents. These organometallic passivating agents are highly toxic and harmful to human health and the environment, limiting their use. Furthermore, the stability of the passivating agent also affects its performance.

[0015] Therefore, in order to reduce the adverse effects of metal contaminants such as iron, nickel, and vanadium contained in catalytic cracking feedstock on catalysts, despite recent advancements in catalyst, additive, and metal passivator technologies, there is still a need for new additive preparation technologies that are environmentally friendly, simple, and feasible, while also possessing excellent resistance to metal contamination such as iron, nickel, and vanadium. Summary of the Invention

[0016] To address the aforementioned problems, the present invention aims to provide an anti-metal contamination catalytic cracking additive and its preparation method, wherein the anti-metal contamination catalytic cracking additive has good anti-metal contamination ability, cracking reaction selectivity, and performance.

[0017] To achieve the above objectives, the present invention provides an anti-metal contamination catalytic cracking additive, which, calculated by weight of 100%, comprises: 4-40% phosphorus (based on P2O5), 1-15% alumina nanofibers (based on a dry basis), 1-10% flake aluminum phosphate (based on a dry basis), 2-50% titanium-modified clay, 0-30% aluminum compounds (based on oxides), 0-20% alkaline earth metals (based on oxides), 0-70% clay (based on a dry basis), and 0-10% inorganic carrier material (based on oxides); wherein the preparation method of the titanium-modified clay includes the following steps:

[0018] (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-modified clay; the titanium-modified clay 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%.

[0019] According to a specific embodiment of the present invention, preferably, the composition of the anti-metal contamination catalytic cracking additive, calculated as 100% by weight, comprises: 10-30% phosphorus as P2O5, 3-15% alumina nanofibers on a dry basis, 3-8% flake aluminum phosphate on a dry basis, 5-20% titanium-modified clay, 5-25% aluminum compounds on an oxide basis, 1-10% alkaline earth metals on an oxide basis, 5-62% clay on a dry basis, and 0-8% inorganic carrier material on an oxide basis.

[0020] According to a specific embodiment of the present invention, preferably, the solid content of the titanium-modified clay is 10-45 wt%.

[0021] According to a specific embodiment of the present invention, preferably, the titanium-modified clay comprises 7-30 wt% titanium as oxide, 8-40 wt% aluminum as oxide, and 35-70 wt% silicon as oxide, calculated on a dry basis of 100%.

[0022] According to a specific embodiment of the present invention, preferably, in the preparation method of the titanium modified clay, the mixed raw materials further include a dispersant; calculated on a dry basis of 100% of the titanium modified clay, the content of the dispersant is less than 10%, more preferably 0.3-5%.

[0023] 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.

[0024] According to a specific embodiment of the present invention, preferably, in the preparation method of the titanium modified clay, 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.

[0025] According to a specific embodiment of the present invention, preferably, in the preparation method of the titanium modified clay, the titanium tetrachloride solution is pure titanium tetrachloride.

[0026] According to a specific embodiment of the present invention, preferably, in the preparation method of the titanium modified clay, the clay includes one or more combinations of kaolin, hydrous kaolin, montmorillonite, diatomite, halloysite, sepiolite, and bentonite.

[0027] According to a specific embodiment of the present invention, preferably, in the preparation method of the titanium modified clay, the calcination is carried out at 400-900℃ for 0.5-6 hours.

[0028] According to a specific embodiment of the present invention, preferably, the preparation method of the titanium modified clay 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 modified clay.

[0029] According to a specific embodiment of the present invention, preferably, in the preparation method of titanium modified clay, 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.

[0030] 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.

[0031] 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, it 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.

[0032] According to a specific embodiment of the present invention, preferably, the alumina nanofibers have a diameter of 20-100 nm, a length of 0.1-5 μm, and a specific surface area ≥400 m². 2 / g, pore volume ≥1.5cm 3 / g.

[0033] 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.

[0034] According to a specific embodiment of the present invention, preferably, the aluminum compound includes one or more of aluminum oxide, aluminum hydroxide, aluminum sol, and boehmite.

[0035] According to a specific embodiment of the present invention, preferably, the phosphorus compound includes one or more of phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphate, pyrophosphate, polyphosphate, polyphosphate, metaphosphate, and metaphosphate, more preferably one or more of phosphoric acid, ammonium phosphate, ammonium hydrogen phosphate, diammonium hydrogen phosphate, phosphorous acid, and ammonium phosphite.

[0036] According to a specific embodiment of the present invention, preferably, the clay includes one or more of kaolin, hydrous kaolin, montmorillonite, halloysite, and pyrophyllite bentonite, and more preferably one or more of kaolin, hydrous kaolin, and halloysite.

[0037] According to a specific embodiment of the present invention, preferably, the aluminum compound includes one or more of boehmite, amorphous alumina, and aluminosilicate, but does not contain alumina nanofibers.

[0038] According to a specific embodiment of the present invention, preferably, the alkaline earth metal includes one or more of magnesium, calcium, and barium.

[0039] According to a specific embodiment of the present invention, preferably, the alkaline earth metal is derived from one or more combinations of oxides, chlorides, nitrates, carbonates, oxalates, and acetates of magnesium, calcium, and barium.

[0040] According to a specific embodiment of the present invention, preferably, the inorganic carrier material includes one or a combination of two or more of zirconium oxides, chlorides, nitrates, carbonates, sulfates, oxalates, and acetates.

[0041] According to a specific embodiment of the present invention, preferably, the composition of the anti-metal contamination catalytic cracking additive further includes a pore structure improver; the weight of the pore structure improver is less than 10% (more preferably 0.5-6%) of the total weight of the anti-metal contamination catalytic cracking additive, so as to improve the dispersibility of the colloid during the preparation of the additive and improve the pore structure, specific surface area and other properties of the additive.

[0042] 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, polyvinyl alcohol, and polyethylene glycol; more preferably, the methylcellulose is hydroxymethylcellulose and / or carboxymethylcellulose.

[0043] The present invention also provides a method for preparing the above-mentioned anti-metal pollution catalytic cracking aid, which includes the following steps: (1) mixing and pulping phosphorus compounds, alumina nanofibers, flake aluminum phosphate, titanium modified clay, aluminum compounds, alkaline earth metal compounds, clay, and inorganic carrier materials (preferably with added pore structure improvers) to obtain a slurry; (2) spray drying the slurry to form a shape, and then calcining and curing to obtain the anti-metal pollution catalytic cracking aid.

[0044] According to a specific embodiment of the present invention, preferably, the flake aluminum phosphate 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 flake aluminum phosphate 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] 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.

[0047] The anti-metal contamination catalytic cracking additive of the present invention reduces the harmful effects of iron, nickel, and vanadium on the catalyst through the following design scheme: (1) using phosphorus compounds, titanium-modified clay, aluminum compounds, and alkaline earth metal compounds to capture and passivate contaminating metals such as iron, nickel, and vanadium in the feedstock, so that the contaminating metals form stable compounds with the phosphorus compounds, titanium-modified clay, aluminum compounds, and alkaline earth metal compounds in the additive, reducing their deposition on the catalyst, thereby maintaining the excellent cracking reaction performance and performance of the catalyst; (2) the additive does not contain Y-type molecular sieves, which can avoid a large amount of phosphorus and alkali contamination. The adverse effects of alkaline earth metals on the molecular sieve structure and cracking reaction selectivity, and fully ensure the capture and passivation effects of phosphorus and alkaline earth metals on contaminating metals; (3) The additive does not contain rare earth, avoiding the formation of stable rare earth phosphate with phosphorus and rare earth, thereby reducing the capture and passivation effects of phosphorus on iron, nickel and vanadium; In addition, long rod-shaped alumina nanofibers with different morphological characteristics, sheet-shaped aluminum phosphate, titanium modified clay and pore structure improvers can build unobstructed pore structures in the additive, which can improve the dispersibility of colloids in the preparation of the additive, and improve the pore structure, specific surface area and heavy metal passivation effect of the additive.

[0048] The additive provided by this invention has a simple and environmentally friendly preparation process and does not contain elements such as antimony, bismuth, and tin that are harmful to the human body and are commonly used in metal passivating agents. The content of phosphorus compounds, titanium-modified clay, aluminum compounds, and alkaline earth metal compounds in the additive can be adjusted within a wider range, so that the additive can fully exert its anti-metal contamination performance without affecting the activity and reaction performance of the main catalyst. Attached Figure Description

[0049] Figure 1 This is an appearance diagram of the flake aluminum phosphate in Example 1;

[0050] Figure 2 This is a SEM image of the flake aluminum phosphate from Example 1;

[0051] Figure 3 This is a SEM image of alumina nanofibers. Detailed Implementation

[0052] 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.

[0053] The elemental content of the catalysts and additives in the following samples 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.

[0054] The following are the origins and specifications of the raw materials used:

[0055] (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 (long rods, 200-600nm in length): all provided by Lanzhou Chemical Research Center, Petrochemical Research Institute of China National Petroleum Corporation; kaolin (29wt% loss on ignition), halloysite (16.6wt% loss on ignition), boehmite (36wt% loss on ignition), alumina sol (containing 21.6wt% alumina), boehmite (17.0% loss on ignition), REY zeolite (18.0wt% RE2O3 content, reduced by 7%), USY zeolite (1.2wt% Na2O content, excluding rare earth elements, reduced by 4%): all industrial grade, sourced from Lanzhou Petrochemical Company Catalyst Plant. LDO-70 industrial catalyst: industrial grade, produced by Lanzhou Petrochemical Company Catalyst Plant.

[0056] (2) β-alumina trihydrate (loss on ignition 36%): Produced by Shandong Aluminum Industry Research Institute.

[0057] (3) Magnesium chloride, magnesium oxide, calcium carbonate, phosphoric acid (concentration 85%), ammonium dihydrogen phosphate, zirconium oxide, ferric naphthenate, petroleum ether, 1,3,5-trimethylbenzene, polyethylene glycol, and carboxymethyl cellulose: are all chemical reagents.

[0058] (4) Hydrochloric acid: 36% concentration, chemical reagent.

[0059] The spray drying methods for the catalytic cracking additives in Examples 1-5 and Comparative Examples 1-3 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.

[0060] Example 1

[0061] This embodiment provides an anti-metal contamination catalytic cracking additive, the preparation method of which is as follows:

[0062] 1. Preparation of titanium-modified clay:

[0063] 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 titanium modified clay M-1 was obtained.

[0064] The composition of titanium-modified clay 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 titanium-modified clay M-1.

[0065] 2. Preparation of flake aluminum phosphate:

[0066] 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;

[0067] 3. Preparation of anti-metal contamination catalytic cracking additives:

[0068] 1.59 kg of kaolin (dry basis), 0.24 kg of titanium-modified clay M-1 (dry basis), 0.24 kg of pseudoboehmite (dry basis), 0.15 kg of flake aluminum phosphate PA1-1, and 3.2 kg of deionized water were added to a pulping tank and stirred for 1 hour. Then, 8 mL of hydrochloric acid was added, and the mixture was stirred for 15 minutes. After aging at 50°C for 2 hours, 0.877 kg of phosphoric acid, 0.24 kg of alumina nanofibers (dry basis), and 30 g of carboxymethyl cellulose were added. After mixing and pulping for 1 hour, the resulting slurry was sand-milled to make the average particle size D(v, 0.5) less than 4 μm. The slurry was then spray-dried and calcined to obtain catalytic cracking aid CAT-1.

[0069] The composition of additive CAT-1 is as follows: 53 wt% kaolin (dry basis), 8 wt% titanium-modified clay M-1 (dry basis), 8 wt% alumina nanofibers (dry basis), 5 wt% flake aluminum phosphate PA1-1 (dry basis), 8 wt% alumina from boehmite, and 18 wt% phosphorus pentoxide from phosphoric acid. The gelling solids content of additive CAT-1 is 36%.

[0070] Example 2

[0071] This embodiment provides an anti-metal contamination catalytic cracking additive, the preparation method of which is as follows:

[0072] 1. Preparation of titanium-modified clay:

[0073] 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 titanium modified clay M-2.

[0074] The composition of titanium-modified clay 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 18 wt% solid content of titanium-modified clay.

[0075] 2. Preparation of anti-metal contamination catalytic cracking additives:

[0076] 0.96 kg halloysite (dry basis), 1.2 kg titanium-modified clay M-2 (dry basis), 0.3 kg boehmite (dry basis), 30 g alumina sol (alumina basis), 60 g flake aluminum phosphate PA1-1 (dry basis), and 1.5 kg deionized water were added to a pulping tank and pulped for 0.5 hours. Then, 5 mL of hydrochloric acid was added, and the mixture was stirred for 1 hour. After that, it was aged at 40°C for 1 hour. Then, 0.486 kg of ammonium dihydrogen phosphate, 90 g of alumina nanofibers (dry basis), 30 g of polyethylene glycol, and 60 g of magnesium oxide were added and mixed and pulped for 1.5 hours. 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, catalytic cracking aid CAT-2 was obtained.

[0077] The composition of additive CAT-2 is as follows: halloysite 32 wt% (dry basis), titanium-modified clay M-2 40 wt% (dry basis), alumina nanofibers 3 wt% (dry basis), flake aluminum phosphate PA1-1 2 wt% (dry basis), alumina from boehmite 10 wt%, alumina from aluminum sol 1 wt%, phosphorus pentoxide from ammonium dihydrogen phosphate 10 wt%, and magnesium oxide 2 wt%. The gelling solids content of additive CAT-2 is 28%.

[0078] Example 3

[0079] This embodiment provides an anti-metal contamination catalytic cracking additive, the preparation method of which is as follows:

[0080] 1. Preparation of titanium-modified 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 titanium-modified clay M-3.

[0082] The composition of titanium-modified clay 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 titanium-modified clay M-3 is 30 wt%.

[0083] 2. Preparation of anti-metal contamination catalytic cracking additives:

[0084] 0.48 kg of kaolin (dry basis), 90 g of titanium-modified clay M-3 (dry basis), 0.24 kg of flake aluminum phosphate PA1-1 (dry basis), 0.54 kg of pseudoboehmite (dry basis), 1.525 kg of magnesium chloride, and 3.3 kg of deionized water were added to a pulping tank and stirred for 2 hours. Then, 1.461 kg of phosphoric acid, 0.45 kg of alumina nanofibers (dry basis), and 60 g of 1,3,5-trimethylbenzene were added and mixed and pulped for 0.5 hours. 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, catalytic cracking aid CAT-3 was obtained.

[0085] The composition of additive CAT-3 is as follows: 16 wt% kaolin (dry basis), 3 wt% titanium-modified clay M-3 (dry basis), 15 wt% alumina nanofibers (dry basis), 8 wt% flake aluminum phosphate PA1-1 (dry basis), 18 wt% alumina from boehmite, 30 wt% phosphorus pentoxide from phosphoric acid, and 10 wt% magnesium oxide from magnesium chloride. The gelling solids content of additive CAT-3 is 32%.

[0086] Example 4

[0087] This embodiment provides an anti-metal contamination catalytic cracking additive, the preparation method of which is as follows:

[0088] 0.72 kg of kaolin (dry basis), 0.75 kg of titanium-modified clay M-3 (dry basis), 0.12 kg of zirconium oxide, 0.54 kg of pseudoboehmite (dry basis), 0.15 kg of boehmite (dry basis), 90 g of flake aluminum phosphate PA1-1 (dry basis) and 3.8 kg of deionized water were added to a pulping tank and pulped. After stirring for 1 hour, 54 g of calcium carbonate, 0.15 kg of alumina nanofibers (dry basis), 0.731 kg of phosphoric acid and 120 g of carboxymethyl cellulose were added. After mixing and pulping for 2 hours, the resulting slurry was sand-milled to make the average particle size D(v, 0.5) of the slurry less than 4 μm. The slurry was then spray-dried and calcined to obtain catalytic cracking aid CAT-4.

[0089] The composition of additive CAT-4 is as follows: 24 wt% kaolin (dry basis), 25 wt% titanium-modified clay M-3 (dry basis), 5 wt% alumina nanofibers (dry basis), 3 wt% flake aluminum phosphate PA1-1 (dry basis), 4 wt% zirconium oxide (dry basis), 18 wt% alumina from boehmite, 5 wt% alumina from boehmite, 15 wt% phosphorus pentoxide from phosphoric acid, and 1 wt% calcium oxide from calcium carbonate. The gelling solids content of additive CAT-4 is 32%.

[0090] The water droplet volume of the additive CAT-4 is 0.30 mL / g.

[0091] Example 5

[0092] This embodiment provides an anti-metal contamination catalytic cracking additive, the preparation method of which is as follows:

[0093] 1. Preparation of flake aluminum phosphate:

[0094] 0.16 kg of pseudoboehmite (dry basis) and 1.92 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 60 °C for 20 minutes, then at 160 °C for 0.5 h. After drying, the mixture was calcined at 650 °C for 2 h to obtain flake aluminum phosphate PA1-2.

[0095] 2. Preparation of titanium-modified clay:

[0096] 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, and titanium-modified clay M-4 was obtained.

[0097] The composition of titanium-modified clay M-4 is as follows: 93 wt% (dry basis) of kaolin roasting material, 7 wt% (calculated as titanium oxide) of titanium tetrachloride, and 25 wt% of solid content of titanium-modified clay M-4.

[0098] 3. Preparation of anti-metal contamination catalytic cracking additives:

[0099] 1.83 kg of kaolin (dry basis), 0.45 kg of titanium-modified clay M-4 (dry basis), 0.45 kg of pseudoboehmite (dry basis), 30 g of flake aluminum phosphate PA1-2, and 3.8 kg of deionized water were added to a pulping tank and stirred for 1 hour. Then, 2.5 mL of hydrochloric acid was added, and the mixture was stirred for 20 minutes. After aging at 60°C for 1 hour, 0.195 kg of phosphoric acid, 0.12 kg of alumina nanofibers (dry basis), and 15 g of carboxymethyl cellulose were added. After mixing and pulping for 1 hour, the resulting slurry was sand-milled to make the average particle size D(v, 0.5) less than 4 μm. The slurry was then spray-dried and calcined to obtain the catalytic cracking aid CAT-5.

[0100] The composition of additive CAT-5 is as follows: 61 wt% kaolin (dry basis), 15 wt% titanium-modified clay M-4 (dry basis), 4 wt% alumina nanofibers (dry basis), 1 wt% flake aluminum phosphate PA1-2 (dry basis), 15 wt% alumina derived from boehmite, and 4 wt% phosphorus pentoxide derived from phosphoric acid. The gelling solids content of additive CAT-5 is 32%.

[0101] Comparative Example 1

[0102] This comparative example provides a catalytic cracking aid, the preparation method of which is as follows:

[0103] 1.71 kg of kaolin (dry basis), 0.12 kg of zirconium oxide, 0.54 kg of pseudoboehmite (dry basis), 0.15 kg of boehmite (dry basis) and 4.9 kg of deionized water were added to a pulping tank and pulped. After stirring for 1 hour, 54 g of calcium carbonate and 0.731 kg of phosphoric acid were added. After mixing and pulping for 2 hours, the mixture was homogenized, spray-dried and calcined to obtain the comparative additive DCAT-1.

[0104] The composition of additive DCAT-1 is as follows: 57 wt% kaolin (dry basis), 4 wt% zirconium oxide (dry basis), 18 wt% alumina from boehmite, 5 wt% alumina from boehmite, 15 wt% phosphorus pentoxide from phosphoric acid, and 1 wt% calcium oxide from calcium carbonate. The gelling solids content of additive DCAT-1 is 32%.

[0105] The water droplet volume of the additive DCAT-1 is 0.20 mL / g.

[0106] Comparative Example 2

[0107] This comparative example provides a catalytic cracking aid, which is prepared according to the method of Example 1 in CN100478420C:

[0108] 1.05 kg of β-alumina trihydrate (dry basis), 120 g of USY zeolite (dry basis), 60 g of REY zeolite (dry basis), 1.713 kg of kaolin (dry basis), 183 g of magnesium chloride, 39 g of diammonium hydrogen phosphate, and 4.6 kg of deionized water were added to a pulping tank and pulped for 1 hour to obtain a slurry with a solid content of 33% by weight. The slurry was homogenized, spray-dried into particles of 40-150 micrometers, and calcined at 500℃ for 1 hour to obtain the comparative additive DCAT-2.

[0109] The composition of additive DCAT-2 is as follows: 57.1 wt% kaolin (dry basis), 35 wt% β-alumina trihydrate (dry basis), 4 wt% USY zeolite (dry basis), 2 wt% REY zeolite (dry basis), 0.7 wt% phosphorus pentoxide from diammonium hydrogen phosphate, and 1.2 wt% magnesium oxide from magnesium chloride. The gelling solids content of additive DCAT-2 is 33%.

[0110] Comparative Example 3

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

[0112] 1. A comparative titanium-modified clay containing titanium and clay without calcination, the preparation method of which is as follows:

[0113] 1499g halloysite (dry basis) was crushed to an average particle size D(v, 0.5) < 4μm, 6.9L of decationized water was added and stirred, 793g of waste liquid containing titanium tetrachloride was added, the temperature was raised to 90℃ and stirred for 2 hours, and the pH value was adjusted to 2.5 with ammonia water to obtain titanium modified clay DM-1.

[0114] The composition of titanium-modified clay DM-1 is: halloysite 83.3 wt% (dry basis), titanium from waste liquid containing titanium tetrachloride 16.7 wt% (calculated as titanium oxide), and the solid content of titanium-modified clay is 18 wt%.

[0115] 2. Preparation of anti-metal contamination catalytic cracking additives:

[0116] 0.96 kg halloysite (dry basis), 1.2 kg titanium-modified clay DM-1 (dry basis), 0.3 kg boehmite (dry basis), 30 g alumina sol (alumina basis), 60 g flake aluminum phosphate PA1-1 (dry basis), and 1.5 kg deionized water were added to a pulping tank and pulped for 0.5 hours. Then, 5 mL of hydrochloric acid was added, and the mixture was stirred for 1 hour. After that, it was aged at 40°C for 1 hour. Then, 0.486 kg of ammonium dihydrogen phosphate, 90 g of alumina nanofibers (dry basis), 30 g of polyethylene glycol, and 60 g of magnesium oxide were added and mixed and pulped for 1.5 hours. 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 to obtain the comparative additive DCAT-3.

[0117] The composition of additive DCAT-3 is as follows: halloysite 32 wt% (dry basis), titanium-modified clay DM-1 40 wt% (dry basis), alumina nanofibers 3 wt% (dry basis), flake aluminum phosphate PA1-1 2 wt% (dry basis), alumina from boehmite 10 wt%, alumina from aluminum sol 1 wt%, phosphorus pentoxide from ammonium dihydrogen phosphate 10 wt%, and magnesium oxide 2 wt%. The gelling solids content of additive DCAT-3 is 28%.

[0118] Compared with the additive DCAT-1 prepared in Comparative Example 1, the additive CAT-4 prepared in Example 4, due to the addition of titanium-modified clay M-3, alumina nanofibers, flake aluminum phosphate PA1-1 and carboxymethyl cellulose during the preparation process, achieved a water droplet pore volume of 0.30 mL / g, which is 50% higher than that of the comparative additive DCAT-1 (water droplet pore volume of 0.20 mL / g).

[0119] Compared to the additive DCAT-3 prepared in Comparative Example 3, the additive CAT-2 prepared in Example 2, due to the calcination treatment of the clay, exhibits a lower wear index, better wear resistance, and larger pore volume. Its pore volume measured by water droplet method reaches 0.30 mL / g, and its wear index is 1.1%, while the comparative additive DCAT-3 has a pore volume measured by water droplet method of 0.18 mL / g and a wear index of 8.9%. The wear index of DCAT-3 is too high and cannot meet the requirements for use as a catalytic cracking additive (generally, the wear index should be below 3.5%).

[0120] The industrial catalyst LDO-70 was mixed with the auxiliary agent CAT-1 prepared in Example 1 and the comparative auxiliary agent DCAT-2 prepared in Comparative Example 2 at a weight ratio of 9:1. The resulting catalyst mixtures and the LDO-70 industrial catalyst were then subjected to iron contamination: impregnation in a petroleum ether solution of ferric naphthenate for 1 hour, drying at 120°C, and calcination at 600°C for 2 hours, resulting in 8000 μg / g of iron contamination on the catalyst mixture. After aging at 800°C with 100% steam for 10 hours, the catalytic cracking performance was evaluated using a heavy oil microreactor (ACE) device. The evaluation results are listed in Table 1.

[0121] Wherein, total liquid yield = LPG yield + gasoline yield + diesel yield; coke factor = (100 - conversion rate) × coke yield / conversion rate.

[0122] Table 1. Results of Selectivity Evaluation for Catalytic Cracking

[0123]

[0124] Table 1 shows that, compared with the LDO-70 industrial catalyst, the use of the additive CAT-1 provided by this invention still resulted in higher conversion and total liquid yield, despite the presence of up to 8000 μg / g of iron contamination on the catalyst mixture. The conversion and total liquid yield increased by 1.83 percentage points and 1.68 percentage points, respectively, while the hydrogen / methane and coke factors decreased. This indicates that the use of the additive CAT-1 provided by this invention promotes efficient conversion of heavy oil, reduces dehydrogenation during catalytic cracking, reduces coking, and improves the selectivity of catalytic cracking. The additive of this invention has a good effect against heavy metal iron.

[0125] Compared with the LDO-70 industrial catalyst, although the conversion rate and total liquid yield were also improved when using the additive DCAT-2 prepared in Comparative Example 2, the improvement was less than that when using the additive CAT-1 provided by the present invention. The hydrogen / methane and coke factor were also higher when using the additive CAT-1 provided by the present invention, indicating that the iron resistance performance of the additive CAT-1 provided by the present invention is better than that of the additive DCAT-2 prepared in Comparative Example 2.

[0126] The industrial catalyst with industrial grade LDO-70 was mixed with the additives CAT-1, CAT-2, CAT-3, CAT-4, and CAT-5 prepared in Examples 1-5 at a weight ratio of 9:1. The resulting catalyst mixture and the LDO-70 industrial catalyst were impregnated with 3000 μg / g Ni and 5000 μg / g V (relative to the catalyst). After the catalysts contaminated with nickel and vanadium were aged at 800°C and 100% water vapor for 4 hours, the catalytic cracking reaction performance was evaluated on a heavy oil microreactor evaluation device (ACE). The evaluation results are listed in Table 2.

[0127] Wherein, total liquid yield = LPG yield + gasoline yield + diesel yield; coke factor = (100 - conversion rate) × coke yield / conversion rate.

[0128] Table 2 Evaluation results of catalytic cracking reaction

[0129]

[0130] In Table 2, the additives CAT-1, CAT-2, CAT-3, CAT-4, and CAT-5 prepared in Examples 1, 2, 3, 4, and 5, when mixed with the base agent LDO-70 industrial catalyst at a weight ratio of 9:1, still exhibited high conversion rates and total liquid yields even with V contamination levels of 5000 μg / g and Ni contamination levels of 3000 μg / g. The conversion rates increased by more than 3.50 percentage points, and the total liquid yield increased by more than 1.50 percentage points. The hydrogen / methane and coke factors decreased, demonstrating excellent resistance to nickel and vanadium. This indicates that using the additives CAT-1, CAT-2, CAT-3, CAT-4, and CAT-5 provided by this invention promotes efficient conversion of heavy oil, reduces dehydrogenation reactions during catalytic cracking, reduces coking, and improves the selectivity of the catalytic cracking reaction. The additives of this invention have good resistance to heavy metals Ni and V, and exhibit strong heavy oil conversion capabilities, low coking, ease of use, low dosage, and rapid effectiveness.

Claims

1. A metal-contamination-resistant catalytic cracking additive, comprising, by weight of 100%, the following components: 4-40% phosphorus as P2O5, 1-15% alumina nanofibers as dry basis, 1-10% flake aluminum phosphate as dry basis, 2-50% titanium-modified clay, 0-30% aluminum compounds as oxides, 0-20% alkaline earth metals as oxides, 0-70% clay as dry basis, and 0-10% inorganic carrier materials as oxides. in, The preparation method of the titanium-modified clay 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-modified clay; Based on a dry basis of 100%, the titanium-modified clay 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 anti-metal contamination catalytic cracking additive according to claim 1, wherein, Based on the weight of the aforementioned anti-metal contamination catalytic cracking additive as 100%, its composition includes: 10-30% phosphorus as P2O5, 3-15% alumina nanofibers on a dry basis, 3-8% flake aluminum phosphate on a dry basis, 5-20% titanium-modified clay, 5-25% aluminum compounds on an oxide basis, 1-10% alkaline earth metals on an oxide basis, 5-62% clay on a dry basis, and 0-8% inorganic carrier materials on an oxide basis.

3. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, The solid content of the titanium-modified clay is 10-45 wt%.

4. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, Based on a dry basis of 100%, the titanium-modified clay comprises 7-30 wt% titanium as oxide, 8-40 wt% aluminum as oxide, and 35-70 wt% silicon as oxide.

5. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, In the preparation method of the titanium modified clay, 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 modified clay of 100%.

6. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, In the preparation method of the titanium-modified clay, the clay includes one or more of kaolin, montmorillonite, diatomite, and sepiolite.

7. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, In the method for preparing the titanium-modified clay, the clay includes halloysite.

8. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, In the preparation method of the titanium-modified clay, the clay includes bentonite and / or hydrous kaolin.

9. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, The preparation method of the titanium-modified clay 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-modified clay.

10. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, In the preparation method of titanium modified clay, after the reaction in step (2) is completed, the pH value of the reaction system is 0.5-8.

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

12. The anti-metal contamination catalytic cracking additive 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 anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, The phosphorus is derived from one or more of the following: phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphate, pyrophosphate, polyphosphate, polyphosphate, metaphosphate, and metaphosphate.

14. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, The alumina nanofibers have a diameter of 20-100 nm, a length of 0.1-5 μm, and a specific surface area ≥400 m². 2 / g, pore volume ≥1.5cm 3 / g.

15. The anti-metal contamination catalytic cracking additive 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.

16. The anti-metal contamination catalytic cracking additive according to claim 15, wherein, The aluminum compounds include one or more of aluminum oxide, aluminum hydroxide, aluminum sol, and boehmite.

17. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, In clay comprising 0-70% on a dry basis, the clay includes one or more of kaolin, montmorillonite, and pyrophyllite.

18. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, In clays comprising 0-70% on a dry basis, the clays include halloysite.

19. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, In clays comprising 0-70% on a dry basis, the clays include bentonite and / or hydrous kaolinite.

20. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, The aluminum compound includes one or more of boehmite, boehmite, amorphous alumina, and aluminosilicate.

21. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, The alkaline earth metals include one or more of magnesium, calcium, and barium.

22. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, The inorganic carrier material includes one or more of zirconium oxides, chlorides, nitrates, carbonates, sulfates, oxalates, and acetates.

23. The anti-metal contamination catalytic cracking additive according to claim 1 or 2, wherein, The composition of the anti-metal contamination catalytic cracking aid also includes a pore structure improver; the weight of the pore structure improver is less than 10% of the total weight of the anti-metal contamination catalytic cracking aid.

24. The anti-metal contamination catalytic cracking additive according to claim 23, wherein, The pore structure improver includes one or more of 1,3,5-trimethylbenzene, 1,3,5-triisopropylbenzene, methylcellulose, polyvinyl alcohol, and polyethylene glycol.

25. A method for preparing the anti-metal contamination catalytic cracking additive according to any one of claims 1-24, comprising the following steps: (1) Mix phosphorus compounds, alumina nanofibers, sheet aluminum phosphate, titanium-modified clay, aluminum compounds, alkaline earth metal compounds, clay, and inorganic carrier materials to obtain a slurry; (2) The slurry is spray-dried and shaped, and then calcined and cured to obtain the anti-metal pollution catalytic cracking aid.

26. The preparation method according to claim 25, wherein, The average particle size D(v, 0.5) of the slurry in step (2) is <4 μm.

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