Catalytic cracking aid and preparation method thereof

Abstract

The invention provides a catalytic cracking aid and a preparation method thereof. The catalytic cracking aid is prepared from the following components in percentage by dry basis: 15 to 55 percent of ZSM-5 molecular sieve, 0 to 55 percent of clay, 1 to 15 percent of aluminum oxide nanofiber, 1 to 10 percent of flaky aluminum phosphate, 4 to 70 percent of titanium-containing composite binder and 0 to 10 percent of binder, wherein the molecular sieve is ZSM-5 molecular sieve, the clay is clay, the aluminum oxide nanofiber is alumina nanofiber, the flaky aluminum phosphate is flaky aluminum phosphate, the titanium-containing composite binder is titanium-containing composite binder, and the binder is oxide. 5-20% of phosphorus in terms of oxide and 0-5% of a modified metal compound in terms of oxide; wherein waste liquid containing titanium tetrachloride generated in the preparation process of the polypropylene catalyst is utilized in the preparation of the titanium-containing composite binder. The catalytic cracking aid can promote the conversion of heavy oil in the catalytic cracking process, increases the total liquid yield (liquefied gas + gasoline + diesel oil) and reduces green coke while increasing the yield of low-carbon olefins such as ethylene / propylene, and has excellent cracking reaction selectivity and use performance.

Description

Technical Field

[0001] The invention belongs to the field of oil refining catalysts and additives, and relates to a catalytic cracking additive, in particular to a catalytic cracking additive used for heavy oil cracking to reduce coke yield, increase total liquid yield and low-carbon olefin yield, and a preparation method thereof. Background Art

[0002] In the process of industrial production of polyolefins, the widely used catalyst is mainly Ziegler-Natta catalyst, which is a titanium catalyst. Regarding the preparation of titanium polyolefin catalysts, for example, patent CN102336851B discloses a propylene polymerization catalyst, including magnesium, titanium, halogen and internal electron donor compounds diisobutyl phthalate, diethyl phthalate or di-n-butyl phthalate and a mixture of succinate; patent CN107434832B discloses a propylene polymerization catalyst, mainly composed of alcohol magnesium compounds, titanium compounds and phosphate electron donor compounds. The common method for preparing titanium catalysts at present is: firstly prepare magnesium halide alcohol compound, for example, after magnesium halide and alcohol are heated and dissolved, high pressure ejection or high speed stirring is used, and the method of solidifying into microsphere particles in a cooling medium is obtained, and the specific steps are referred to the relevant description in CN1110281A; then the magnesium halide alcohol compound particles are reacted with halogen-containing compounds such as titanium tetrachloride to prepare a magnesium-supported catalyst, during which various promoters can be added for modification. In the above-mentioned catalyst preparation process, a large amount of titanium tetrachloride needs to be used, and the excess ratio is very large. At the same time, the solid catalyst component obtained needs to be washed with a hydrocarbon solvent (such as hexane) to remove the titanium tetrachloride not loaded therein. Therefore, in the polyolefin catalyst production process, after the catalyst solid is separated and precipitated, a large amount of catalyst mother liquid containing at least one of titanium tetrachloride, unreacted hydrocarbons, unreacted halogenated alkoxy titanium, alkoxy magnesium, and unreacted esters will be produced. The titanium tetrachloride waste liquid generated in the titanium polypropylene catalyst preparation process contains, in addition to titanium tetrachloride (at least 80% or more), a small amount of alkoxy titanium complex (for example, about 2%-5%), a small amount of lipids, and n-hexane. If the waste liquid is directly discarded, it is bound to cause environmental pollution and waste of resources, so it needs to be effectively utilized.

[0003] Regarding the treatment and utilization of waste liquid containing titanium tetrachloride generated during the preparation of polypropylene catalyst, CN106277046B discloses a method for treating waste liquid containing titanium tetrachloride, wherein the waste liquid contains titanium tetrachloride, an organic solvent, and halogenated alkoxy titanium and / or alkoxy titanium. The method comprises: (1) contacting the waste liquid containing titanium tetrachloride with water for hydrolysis; and (2) distilling the waste liquid after hydrolysis 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 comprising: (1) introducing waste liquid from the production of polyolefin catalysts and hydrolysis water into a hydrolysis reactor for continuous hydrolysis reaction to obtain gas phase logistics I and solid-liquid mixed phase logistics; (2) incinerating the solid-liquid mixed phase logistics to obtain gas phase logistics II and solid phase logistics I containing TiO2; (3) performing dust removal treatment on the gas phase logistics I and the gas phase logistics II to obtain gas phase logistics III and solid phase logistics II containing TiO2; (4) performing hydrochloric acid absorption treatment on the gas phase logistics III. The method realizes the pollution-free discharge treatment process of 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 sieve, titanium-containing catalytic material, titanium-containing catalyst and auxiliary agent from titanium tetrachloride, CN107866211B discloses a TiO2 sol and a catalytic cracking catalyst and their preparation methods, wherein the titanium-chlorine molar ratio of the TiO2 sol is (0.2-0.6): 1; and the corrosion rate of the TiO2 sol is ≤1g / m 2 ·h, pH value is 5-8, and viscosity at 20°C is ≥1000mPa·s. The provided TiO2 sol has the characteristics of high viscosity, low corrosion rate, and high pH value. When used as a binder for preparing a catalytic cracking catalyst, it is beneficial to increase the specific surface area of ​​the catalytic cracking catalyst, improve the sphericity of the catalytic cracking catalyst, enhance the activity of the catalytic cracking catalyst, improve the product distribution of the catalytic cracking reaction, and is mainly beneficial to the generation of the target product gasoline.

[0006] CN102114429B discloses a method for increasing the B acid content of ZSM-5 molecular sieve and increasing the production of light olefins. The method comprises modifying the ZSM-5 molecular sieve with iron and titanium at the same time. After modification, the mass ratio of iron to titanium in the molecular sieve is 0.3-3:1, thereby improving the catalytic reactivity of the molecular sieve, promoting the conversion of long-chain alkanes and aromatic hydrocarbons with long-chain alkyl side chains, such as isopropylbenzene, and achieving the effect of significantly increasing the yield of light olefins.

[0007] CN109694721B discloses a macroporous kaolinite and its preparation and application. The macroporous kaolinite contains a modified metal, and the average pore diameter is 2-50nm. The pore volume of pores with a pore diameter of 10-50nm accounts 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 comprises: first calcining the kaolinite; forming a mixture of the kaolinite after the first calcination and a first acid, water, and an optional modified metal compound, performing a first treatment, then performing a second calcination, and then forming a mixture with a second acid, water, a pore expander and an optional modified metal compound for a second treatment, filtering and drying to obtain macroporous kaolinite, and adding a modified metal compound in at least one step of the first treatment and the second treatment. The macroporous kaolinite can be used to prepare a cracking catalyst. The obtained catalyst has high heavy oil conversion activity, high gasoline and liquefied gas yields, low dry gas selectivity, and low coke selectivity.

[0008] CN105618107B discloses a catalytic cracking catalyst and a preparation method thereof. The catalyst contains 10-60 wt% of titanium and / or zirconium modified Y molecular sieve, 10-60 wt% of clay and 5-50 wt% of a binder based on the total weight of the catalyst; the titanium and / or zirconium modified Y molecular sieve contains 1.0 wt%-15.0 wt% of titanium and / or zirconium metal oxide. The catalyst preparation method comprises the steps of preparing titanium and / or zirconium modified Y molecular sieve, preparing catalyst slurry and spray drying, wherein the titanium and / or zirconium modified Y molecular sieve comprises the following steps: (1) dispersing a titanium and / or zirconium-containing compound in water, and adjusting the pH value of the mixture to 3-10; (2) mixing the molecular sieve with the mixture obtained in step (1), stirring; optionally filtering and / or drying; (3) calcining at 300-700°C. The catalyst has a high heavy oil conversion capacity and gasoline yield.

[0009] In the prior art, the titanium tetrachloride-containing waste liquid generated during the preparation of polypropylene catalysts is usually separated from the titanium; the preparation process of titanium-containing kaolinite is complicated, and acid needs to be added and filtered multiple times during the preparation process; the modified ZSM-5 molecular sieve and the corresponding additives do not involve the use in the catalytic cracking process to reduce coke formation, reduce heavy oil yield and increase total liquid yield.

[0010] Therefore, in order to solve the problem of treating the titanium tetrachloride waste liquid generated in the preparation process of polypropylene catalyst, and to solve the adverse effects of high heavy oil yield, high coke production and low total liquid recovery brought by ZSM-5 molecular sieve additives in the heavy oil cracking process, despite the recent additive technology, new additive preparation technology with simple and feasible preparation process and excellent performance is still needed. Summary of the invention

[0011] In order to solve the above problems, the purpose of the present invention is to provide a catalytic cracking aid and a preparation method thereof, which can promote the conversion of heavy oil in the catalytic cracking process, while producing more low-carbon olefins such as ethylene / propylene, increase the total liquid yield (liquefied gas+gasoline+diesel), reduce coke formation, and has excellent cracking reaction selectivity and performance.

[0012] In order to achieve the above object, the present invention provides a catalytic cracking aid, which, based on 100% by weight of the catalytic cracking aid, comprises: 15-55% of ZSM-5 molecular sieve on a dry basis, 0-55% of clay on a dry basis, 1-15% of alumina nanofibers on a dry basis, 1-10% of flaky aluminum phosphate on a dry basis, 4-70% of a titanium-containing composite binder on a dry basis, 0-10% of a binder on an oxide basis, 5-20% of phosphorus on an oxide basis, and 0-5% of a modified metal compound on an oxide basis; wherein the preparation method of the titanium-containing composite binder comprises the following steps:

[0013] (1) mixing calcined clay, water and titanium tetrachloride solution to obtain a mixture; (2) reacting the mixture at 40-120° C. for 0.5-6 hours to obtain the titanium-containing composite binder; based on the dry basis of the titanium-containing composite binder being 100%, the composition of the titanium-containing composite binder comprises 7-45wt% titanium calculated as oxide, 0.6-40wt% aluminum calculated as oxide and 30-92wt% silicon calculated as oxide.

[0014] According to a specific embodiment of the present invention, preferably, based on the weight of the catalytic cracking aid being 100%, its composition comprises: 20-50% of ZSM-5 molecular sieve on a dry basis, 10-50% of clay on a dry basis, 3-15% of alumina nanofibers on a dry basis, 3-8% of flaky aluminum phosphate on a dry basis, 5-40% of a titanium-containing composite binder on a dry basis, 6-19% of phosphorus on an oxide basis, 3-8% of a binder on an oxide basis and 0-3% of a 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 binder is 10-45wt%.

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

[0017] According to a specific embodiment of the present invention, preferably, in the preparation method of the titanium-containing composite binder, the mixed raw materials also include a dispersant; based on the dry basis of the titanium-containing composite binder as 100%, 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 includes one or a combination of two or more of 1,3,5-trimethylbenzene, 1,3,5-triisopropylbenzene, methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, and polyethylene glycol.

[0019] According to a specific embodiment of the present invention, preferably, in the method for preparing 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 a polypropylene catalyst.

[0020] According to a specific embodiment of the present invention, preferably, in the method for preparing the titanium-containing composite binder, 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 a combination of two or more of kaolin, halloysite, montmorillonite, diatomaceous earth, halloysite, sepiolite and bentonite, and more preferably one or a combination of two or more of kaolin, halloysite, diatomaceous earth, halloysite and sepiolite.

[0022] According to a specific embodiment of the present invention, preferably, in the method for preparing the titanium-containing composite binder, the calcination is performed at 400-900° C. for 0.5-6 h.

[0023] According to a specific embodiment of the present invention, preferably, the preparation method of the titanium-containing composite binder comprises the following steps: mixing clay calcined at 550-850°C for 1-3h, water, and waste liquid containing titanium tetrachloride to form a mixture, heating the mixture to 60-120°C and reacting for 0.5-3h to obtain the titanium-containing composite binder.

[0024] According to a specific embodiment of the present invention, preferably, in the method for preparing the titanium-containing composite binder, 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 a combination of two or more of ammonia water, 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 crushed to an average particle size D (v, 0.5) < 4 μm before or after calcination, 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 contains 0.2-8% phosphorus and 0-5% of a second element, calculated as oxide, wherein the second element includes one or a combination of two or more of iron, zinc, magnesium, calcium, titanium, zirconium, lanthanum, cerium and yttrium elements; more preferably, the phosphorus comes from one or a combination of two or more of phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphate, pyrophosphate, polyphosphoric acid, polyphosphate, metaphosphoric acid and metaphosphate, for example, the phosphorus comes from one or a combination of two or more 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 come from one or a combination of two or more 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 comprises one or a combination of two or more of kaolin, halloysite, montmorillonite, diatomaceous earth, halloysite, sepiolite and bentonite, and more preferably one or a combination of two or more of kaolin, halloysite, diatomaceous earth, halloysite and sepiolite.

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

[0029] According to a specific embodiment of the present invention, preferably, the preparation method of the flaky aluminum phosphate is: react an aluminum compound and a phosphorus compound at a molar ratio of P / Al=(2.6-3.4):1 at 40°C-90°C for 0.1-1h, then react at 120°C-170°C for 0.5-3h, dry, and calcine at 400°C-700°C for 0.5-3h to obtain the flaky aluminum phosphate.

[0030] According to a specific embodiment of the present invention, preferably, in the preparation method of the above-mentioned flaky aluminum phosphate, the aluminum compound includes one or more combinations of aluminum oxide, aluminum hydroxide, aluminum sol, and pseudo-boehmite; the phosphorus compound includes one or more combinations of phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphate, pyrophosphate, polyphosphoric acid, polyphosphate, metaphosphoric acid, 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 pseudo-boehmite is acidified and then aged at 40-90°C for 0.5-3 hours for peptization before use; in the process of peptization of pseudo-boehmite with acid, 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, silica-alumina colloid, phosphate-alumina colloid, and acid-soluble pseudo-boehmite.

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

[0033] According to a specific embodiment of the present invention, preferably, the phosphorus comes from one or a combination of two or more of phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphate, pyrophosphate, polyphosphoric acid, polyphosphate, metaphosphoric acid, and metaphosphate. For example, the phosphorus comes from one or a combination of two or more 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 a combination of two or more of 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 aid 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 aid.

[0036] According to a specific embodiment of the present invention, preferably, the pore structure improver includes one or a combination of two or more of 1,3,5-trimethylbenzene, 1,3,5-triisopropylbenzene, methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, and polyethylene glycol.

[0037] The auxiliary agent of the present invention can treat the waste liquid containing titanium tetrachloride generated in the process of preparing polypropylene catalyst by the following technical scheme: (1) After high-temperature calcination, the crystal structure of clay changes. For example, the silicon and aluminum contained in kaolin are mainly kaolinite structures. After high-temperature calcination, kaolinite undergoes phase transformation to form active silicon and active aluminum. Such active silicon and active aluminum can react with acid or alkali; titanium tetrachloride is hydrolyzed to produce titanium oxide and hydrogen chloride. By utilizing 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, and the hydrochloric acid generated by the hydrolysis of titanium tetrachloride reacts with the active aluminum in the calcined clay to prepare a composite binder containing titanium and clay; since the active aluminum in the clay reacts with the hydrochloric acid generated by the hydrolysis of titanium tetrachloride, the active aluminum is separated from the clay. At the same time, the active aluminum reacting with the hydrochloric acid and the fine titanium oxide particles produced by hydrolysis together form a titanium-aluminum mixture, which together with the above-mentioned medium- and macro-porous clay, forms a composite binder containing titanium and clay. This titanium-containing composite binder not only has the function of a binder, but also contains medium- and macro-porous clay components, which is beneficial to improving the pore structure of the catalyst, increasing the proportion of medium- and macro-pores of the catalyst, and improving the diffusion performance. (2) The organic matter contained in the waste liquid containing titanium tetrachloride (the waste liquid is mainly titanium tetrachloride, accounting for 80%-95% by weight, and the rest is mainly hexane, and also contains a small amount of alkoxy titanium complex (about 2-5% by weight) and a small amount of lipids) can also play the role of a template between the components of the molecular sieve or catalyst, decompose and form channels during the high-temperature treatment process of the preparation of the molecular sieve or catalyst, and improve the pore structure of the molecular sieve or catalyst and improve the diffusion performance. The utilization of waste liquid containing titanium tetrachloride is convenient, and there is no need to separate titanium, chlorine and organic matter in the waste liquid containing titanium tetrachloride, which does not increase equipment investment and processing costs; (3) Alumina nanofibers are in the form of long rods and flaky aluminum phosphates are in the form of flakes. By utilizing their different morphological characteristics, combined with titanium-containing composite binders and pore structure improvers, a smooth pore structure is constructed in the additive, thereby improving the diffusion performance of the additive.

[0038] The present invention also provides a method for preparing the above-mentioned catalytic cracking aid, which comprises the following steps: (1) mixing and slurrying ZSM-5 molecular sieve, clay, alumina nanofibers, flaky aluminum phosphate, titanium-containing composite binder, binder, phosphorus compound, and modified metal compound (preferably adding a pore structure improver) to obtain a slurry; (2) spray-drying the slurry to form it, and then calcining and curing it 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 sand-milled before mixing and slurrying and / or the slurry in step (2) is sand-milled 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 less than 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] The present invention does not limit the spray drying method, and the technology known to those skilled in the art can be used, and the process conditions are, for example, the spray tower furnace temperature is controlled at 450-550° C., and the spray tail gas temperature is controlled at 200-300° C. The present invention can control the screening distribution of the spray-formed catalyst microspheres by controlling the spray forming conditions such as the spray pressure and the nozzle size.

[0042] The titanium tetrachloride waste liquid generated in the process of preparing polypropylene catalyst contains about 80%-95% titanium tetrachloride (by weight). If it is discharged into the environment, it will inevitably cause environmental pollution and waste of resources. The present invention uses the titanium tetrachloride waste liquid generated in the process of preparing polypropylene catalyst to prepare a composite binder containing titanium and clay and a catalytic cracking aid, which not only solves the problem of using the titanium tetrachloride waste liquid and avoids its environmental pollution, but also avoids the shortcomings of the prior art. The titanium-containing aid prepared by the present invention is mixed with a catalytic cracking catalyst and used in the heavy oil catalytic cracking process, which can promote the conversion of heavy oil, improve the total liquid yield, reduce coke formation, and have a high yield of low-carbon olefins. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0044] Figure 2 is a SEM image of the flaky aluminum phosphate in Example 1;

[0045] Figure 3 is the SEM image of alumina nanofibers. DETAILED DESCRIPTION

[0046] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0047] The element contents in the following samples, catalysts and additives were determined by X-ray fluorescence analysis. The wear index of the catalyst was analyzed by the MS-C / 6 wear index analyzer produced by Shenyang Kehui Instrument Manufacturing Co., Ltd. The pore volume of the catalyst was determined by the water drop method.

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

[0049] (1) Waste liquid containing titanium tetrachloride (hereinafter referred to as waste liquid containing titanium tetrachloride) generated during the preparation of polypropylene catalyst: titanium content 90% (in terms of TiCl4), alumina nanofibers ( Figure 3 As shown, the specific surface area is 625m 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 China Petroleum and Chemical Industry Research Institute; kaolin (ignition loss 29wt%), halloysite (ignition loss 16.6wt%), pseudo-boehmite (ignition loss 36wt%), aluminum sol (containing 21.6wt% alumina), silica sol (silicon oxide concentration 30wt%), ordinary ZSM-5 molecular sieve (silicon to aluminum ratio 31, mesopore volume 0.04mL / g), phosphorus zinc modified ZSM-5 molecular sieve (silicon to aluminum ratio 31), high silicon ZSM-5 molecular sieve (silicon to aluminum ratio 384): all industrial products, collected from Lanzhou Petrochemical Company Catalyst Plant; LDC-200 catalyst: industrial product, produced by Lanzhou Petrochemical Company Catalyst Plant, treated at 800℃, 100% steam for 17h.

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

[0051] (3) Diatomaceous earth (ignition loss 2.6wt%): industrial product;

[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, polyethylene glycol: all are chemical reagents;

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

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

[0055] Example 1

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

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

[0058] The kaolin was calcined at 750°C for 2 hours to obtain a calcined material, 1674 g (dry basis) of the calcined material was crushed to an average particle size D (v, 0.5) < 4 μm, 5.16 L of decationized water was added and stirred, 332 g of waste liquid containing titanium tetrachloride and 18 g of polyethylene glycol were added, the temperature was raised to 70°C, 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: 93wt% (dry basis) of kaolin calcined material, 7wt% (titanium oxide basis) of titanium from waste liquid containing titanium tetrachloride, and the solid content of the composite binder M-1 is 25wt%;

[0060] 2. Preparation of flake aluminum phosphate:

[0061] 0.14 kg of pseudo-boehmite (dry basis) and 2.67 L of deionized water were added to a pulping tank for pulping, and then 0.955 kg of phosphoric acid was added, reacted at 80°C for 10 minutes, then reacted at 135°C for 1 hour, dried, and calcined at 600°C for 1.5 hours to obtain flaky aluminum phosphate PAl-1, which has the appearance as shown below: Figure 1 As shown, it has a fluffy appearance, and the SEM image is shown in Figure 2 , the morphology is flake-like;

[0062] 3. Preparation of catalytic cracking additives:

[0063] 0.6 kg kaolin (dry basis), 0.24 kg pseudo-boehmite (dry basis), 60 g flaky aluminum phosphate PAl-1 (dry basis), 0.42 kg (solid content) titanium- and clay-containing composite binder M-1 and 2.86 L deionized water were added to a pulping tank for pulping and stirred for 1 hour. Then 32 mL hydrochloric acid was added, stirred for 0.5 hour, and then aged at 50° C. for 2 hours. Then 1.08 kg phospho-zinc modified ZSM-5 molecular sieve (dry basis), 0.12 kg alumina nanofibers (dry basis), 0.585 kg phosphoric acid, and 0.223 kg diammonium hydrogen phosphate were added, mixed and pulped for 1 hour, and the resulting slurry was sand-milled to make the average particle size D (v, 0.5) of the slurry less than 4 μm, spray-dried, and calcined at 550° C. for 2 hours to obtain a catalytic cracking aid CAT-1.

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

[0065] Example 2

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

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

[0068] (1) 1.5 kg of mesoporous ZSM-5 molecular sieve (dry basis) was added to 3.5 L of deionized water and stirred evenly, and then 20 g of waste liquid containing titanium tetrachloride and 103 g of zirconium sulfate were added and stirred for 1.5 h to form a molecular sieve slurry, which was dried at 100 ° C and calcined at 550 ° C for 1.5 h;

[0069] (2) Mix the calcined molecular sieve in step (1) with 3.5 L of deionized water, add 97 g of phosphoric acid, stir evenly, dry at 100 ° C, and calcine at 550 ° C for 1.5 h to obtain a titanium, zirconium, and phosphorus modified mesoporous ZSM-5 molecular sieve Z-1;

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

[0071] The halloysite was crushed to an average particle size D (v, 0.5) < 4 μm, and calcined at 600° C. for 5 hours to obtain a calcined material. 1499 g (dry basis) of the calcined material was added with 7.3 L of decationized water and stirred, and 793 g of waste liquid containing titanium tetrachloride was added, the temperature was raised to 90° C., stirred for 2 hours, and the pH value was adjusted to 2.5 with ammonia water to obtain a composite binder M-2 containing titanium and clay;

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

[0073] 3. Preparation of catalytic cracking additives:

[0074] 150g of flaky aluminum phosphate PAl-1 (dry basis), 60g of alumina nanofibers (dry basis), 5.25kg of a composite binder M-2 containing titanium and clay, 0.18kg of aluminum sol (alumina basis) 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-silicon ZSM-5 molecular sieve (dry basis) and 0.682kg of phosphoric acid were added. After mixing and pulping for 0.5h, the obtained slurry was sand-milled to make the average particle size D (v, 0.5) of the slurry less than 4μm, spray-dried and calcined at 500°C for 1h to obtain a catalytic cracking aid CAT-2.

[0075] The composition of the catalytic cracking additive CAT-2 is: 38wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve Z-1, 2wt% (dry basis) of high-silicon ZSM-5 molecular sieve, 2wt% (dry basis) of alumina nanofiber, 5wt% (dry basis) of flaky aluminum phosphate PAl-1, 31.5wt% (dry basis) of composite binder M-2 containing titanium and clay, 6wt% of alumina from aluminum sol, 1.5wt% of rare earth oxide from rare earth chloride solution, and 14wt% of phosphorus pentoxide from phosphoric acid. The colloid solid content of the additive CAT-2 is 29%.

[0076] Example 3

[0077] This embodiment provides a catalytic cracking aid, and the preparation method thereof 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, stirred for 10 min, the pH value was adjusted to 1.5 with aqueous ammonia, and then 1.418 kg of ordinary ZSM-5 molecular sieve (dry basis) was added, stirred for 0.5 h to form a molecular sieve slurry, dried at 100 ° C, and calcined at 520 ° C for 1.5 h to obtain iron-phosphorus-modified ZSM-5 molecular sieve Z-2;

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

[0081] The kaolin and diatomaceous earth were crushed to an average particle size D (v, 0.5) < 4 μm, and calcined at 850° C. for 2.5 hours to obtain a calcined material. 900 g (dry basis) of the kaolin calcined material, 100.8 g (dry basis) of the diatomaceous earth calcined material, and 72 g of carboxymethyl cellulose were added with 2.0 L of decationized water and stirred, and 2109 g of waste liquid containing titanium tetrachloride was added, the temperature was raised to 60° C., stirred for 3 hours, and the pH value was adjusted to 3.0 with ammonia water to obtain a composite binder M-3 containing titanium and clay;

[0082] The composition of the composite binder M-3 containing titanium and clay is: 50wt% (dry basis) of calcined kaolin material, 5.6wt% (dry basis) of calcined diatomite material, 44.4wt% (titanium oxide) of titanium from waste liquid containing titanium tetrachloride, and the solid content of the composite binder M-3 is 30wt%;

[0083] 3. Preparation of catalytic cracking additives:

[0084] (1) 1.35 kg of modified ZSM-5 molecular sieve Z-2 (dry basis) was added to 2.1 L of deionized water, stirred, and sand-milled 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 of kaolin (dry basis), 30 g of flaky aluminum phosphate PAl-1 (dry basis), 240 g of alumina nanofibers (dry basis), 0.8 kg of a titanium-clay composite binder M-3, 180 g of aluminum sol (alumina), 76.2 g of magnesium chloride, 15 g of lanthanum oxide and 1.1 L of deionized water were added to a pulping tank and stirred for 2 h. Then, the modified molecular sieve Z-2 slurry having an average particle size D (v, 0.5) less than 4 μm and 0.585 kg of phosphoric acid were added. After continuing to pulp for 0.5 h, the mixture was homogenized, spray dried and calcined at 600 ° C for 3 h to obtain a catalytic cracking aid CAT-3.

[0086] The composition of the catalytic cracking aid CAT-3 is: 45wt% (dry basis) of modified ZSM-5 molecular sieve Z-2, 8wt% (dry basis) of alumina nanofiber, 1wt% (dry basis) of sheet aluminum phosphate PAl-1, 8wt% (dry basis) of composite binder M-3, 19wt% (dry basis) of kaolin, 6wt% of aluminum oxide from aluminum sol, 0.5wt% (magnesium oxide) of magnesium from magnesium chloride, 0.5wt% of lanthanum oxide, and 12wt% of phosphorus pentoxide from phosphoric acid. The gelled solid content of the aid CAT-3 is 36%.

[0087] Example 4

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

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

[0090] (1) 1.5 kg of mesoporous ZSM-5 molecular sieve (dry basis) was added to 3.9 L of deionized water, stirred evenly, and then 114 g of titanium tetrachloride was added, the pH value was adjusted to 1.0 with ammonia water, stirred for 0.5 h to form a molecular sieve slurry, dried at 120 ° C, and calcined at 500 ° C for 1 h;

[0091] (2) Mix the calcined molecular sieve of step (1) with 2.4 L of deionized water, add 73 g of phosphoric acid, stir evenly, place in an autoclave at 120° C. for 1 h, then dry at 120° C. and calcine at 500° C. for 1 h to obtain titanium and phosphorus modified mesoporous ZSM-5 molecular sieve Z-3;

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

[0093] The kaolin was crushed to an average particle size D (v, 0.5) < 4 μm, and calcined at 850°C for 2 hours to obtain a 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 stirred for 4 hours. The pH value was 3.6 to obtain the titanium-clay composite binder M-4.

[0094] The composition of the composite binder M-4 containing titanium and clay is: 93wt% (dry basis) of kaolin calcined material, 7wt% (titanium oxide basis) of titanium from titanium tetrachloride, and the solid content of the composite binder M-4 is 25wt%;

[0095] 3. Preparation of catalytic cracking additives:

[0096] 0.24 kg kaolin (dry basis), 0.36 kg halloysite (dry basis), 4.8 kg titanium-clay composite binder M-4, 0.4 kg silica sol and 1.3 L deionized water were added into a pulping tank and stirred for 1 hour. Then, 0.6 kg modified mesoporous ZSM-5 molecular sieve Z-3 (dry basis), 240 g flaky aluminum phosphate PAl-1 (dry basis) and 90 g alumina nanofibers (dry basis) were added and stirred for 30 minutes. Then, 0.244 kg phosphoric acid and 15 g 1,3,5-trimethylbenzene were added. After mixing and pulping for 1 hour, the obtained slurry was sand-milled to make the average particle size D (v, 0.5) of the slurry less than 4 μm. The slurry was spray-dried and calcined at 700° C. for 2 hours to obtain a catalytic cracking aid CAT-4.

[0097] The composition of the catalytic cracking additive CAT-4 is: 20wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve Z-3, 3wt% (dry basis) of alumina nanofiber, 8wt% (dry basis) of sheet aluminum phosphate PAl-1, 40wt% (dry basis) of composite binder M-4 containing titanium and clay, 8wt% (dry basis) of kaolin, 12wt% (dry basis) of halloysite, 4wt% of silicon oxide from silica sol, and 5wt% of phosphorus pentoxide from phosphoric acid. The colloid solid content of the additive CAT-4 is 35%.

[0098] Comparative Example 1

[0099] This comparative example provides a catalytic cracking aid, and its preparation method is as follows:

[0100] 1.14 kg of kaolin (dry basis), 0.3 kg of pseudo-boehmite (dry basis) and 4.0 L of deionized water were added to a pulping tank for pulping and stirred for 1 hour. Then 40 mL of hydrochloric acid was added, stirred for 0.5 hour and aged at 50°C for 2 hours. Then 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 and pulped for 1 hour, homogenized, spray dried and calcined at 550°C for 2 hours to obtain a comparative catalytic cracking aid DCAT-1.

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

[0102] Comparative Example 2

[0103] This comparative example provides a catalytic cracking aid, and its preparation method is as follows:

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

[0105] (1) 1.5 kg of mesoporous ZSM-5 molecular sieve (dry basis) was added to 3.5 L of deionized water, stirred for 1.5 h to form a molecular sieve slurry, dried at 100 ° C, and calcined at 550 ° C for 1.5 h;

[0106] (2) Mix the calcined molecular sieve in step (1) with 3.5 L of deionized water, add 97 g of phosphoric acid, stir evenly, dry at 100 ° C, and calcine at 550 ° C for 1.5 h to obtain a phosphorus-modified mesoporous ZSM-5 molecular sieve DZ-1;

[0107] 2. Preparation of catalytic cracking additives:

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

[0109] The composition of the catalytic cracking aid DCAT-2 is: 38 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve DZ-1, 2 wt% (dry basis) of high-silicon ZSM-5 molecular sieve, 38.5 wt% (dry basis) of halloysite, 6 wt% of alumina from aluminum sol, 1.5 wt% of rare earth oxide from rare earth chloride solution, and 14 wt% of phosphorus pentoxide from phosphoric acid. The gelled solid content of the aid DCAT-2 is 29%.

[0110] Comparative Example 3

[0111] This comparative example provides a catalytic cracking aid, and its preparation method is as follows:

[0112] (1) Add 1.35 kg of modified ZSM-5 molecular sieve Z-2 (dry basis) into 2.1 L of deionized water and stir to form a 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-mentioned molecular sieve Z-2 slurry and 0.585 kg of phosphoric acid were added. After continuing to pulp for 0.5 h, the mixture was homogenized, spray dried, and calcined at 600 ° C for 3 h to obtain the comparative auxiliary agent DCAT-3.

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

[0115] Comparative Example 4

[0116] This comparative example provides a catalytic cracking aid, and its preparation method is as follows:

[0117] 1. A comparative binder containing titanium and clay without calcination, the preparation method of which is as follows:

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

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

[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 comparative composite binder DM-1 containing titanium and clay, 0.4 kg of silica sol and 1.3 L of deionized water were added into a pulping tank and stirred for 1 hour. Then, 0.6 kg of modified mesoporous ZSM-5 molecular sieve Z-3 (dry basis), 240 g of flaky aluminum phosphate PAl-1 (dry basis) and 90 g of alumina nanofibers (dry basis) were added and stirred for 30 minutes. Then, 0.244 kg of phosphoric acid and 15 g of 1,3,5-trimethylbenzene were added. After mixing and pulping for 1 hour, the obtained slurry was sand-milled to make the average particle size D (v, 0.5) of the slurry less than 4 μm. The slurry was spray-dried and calcined at 700°C for 2 hours to obtain a catalytic cracking aid DCAT-4.

[0122] The composition of the catalytic cracking aid DCAT-4 is: 20 wt% (dry basis) of modified mesoporous ZSM-5 molecular sieve Z-3, 3 wt% (dry basis) of alumina nanofiber, 8 wt% (dry basis) of sheet aluminum phosphate PAl-1, 40 wt% (dry basis) of comparative composite binder DM-1 containing titanium and clay, 8 wt% (dry basis) of kaolin, 12 wt% (dry basis) of halloysite, 4 wt% of silicon oxide from silica sol, and 5 wt% of phosphorus pentoxide from phosphoric acid. The gelled solid content of the aid DCAT-4 is 35%.

[0123] Test Example 1

[0124] The catalytic cracking aids CAT-1, CAT-2, CAT-3, CAT-4 prepared in Examples 1-4 and the comparative catalytic cracking aids DCAT-1, DCAT-2, DCAT-3 prepared in Comparative Examples 1-4 were subjected to analytical tests on anti-wear performance and pore volume. The test results are shown in Table 1.

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

[0126] Catalytic cracking additives 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 the present invention have smaller wear index, better anti-wear performance, and larger pore volume.

[0128] In Table 1, the wear index of DCAT-4 is too high and cannot meet the use requirements of catalytic cracking additives (generally the wear index should be lower than 3.5%); compared with DCAT-4, the additive CAT-4 has a low wear index and good anti-wear performance.

[0129] Test Example 2

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

[0131] The industrial catalyst with industrial grade LDC-200QH was uniformly mixed with the catalytic cracking aids CAT-1, CAT-2, 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 groups of catalyst mixtures. After the 6 groups of catalyst mixtures were aged at 800° C. and 100% water vapor for 17 h, the catalytic cracking reaction performance was evaluated on a heavy oil micro-reactor evaluation device (ACE).

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

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

[0134] Table 2 Evaluation results of catalytic cracking reaction selectivity of 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, the catalytic cracking reaction conversion rate increased by 0.66 percentage points, the total liquid yield of the catalytic cracking reaction (liquefied gas + gasoline + diesel) increased by 1.26 percentage points, the coke yield decreased by 0.62 percentage points, the coke factor decreased, and the yield of light olefins (ethylene + propylene + butene) increased by 2.3 percentage points, showing excellent heavy oil conversion, reduced coke generation and high yield of light olefins; 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, the catalytic cracking reaction conversion rate increased by 1.04 percentage points, the total liquid yield of the catalytic cracking reaction (liquefied gas + gasoline + diesel) increased by 1.26 percentage points, the coke yield decreased by 0.62 percentage points, the coke factor decreased, and the yield of light olefins (ethylene + propylene + butene) increased by 2.3 percentage points. Gas + gasoline + diesel) increased by 1.36 percentage points, coke yield decreased by 0.68 percentage points, coke factor decreased, and light olefin (ethylene + propylene + butene) yield increased by 3.13 percentage points, showing excellent heavy oil conversion, reduced coke and more light olefins; 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, the catalytic cracking reaction conversion rate increased by 0.95 percentage points, the total liquid yield of the catalytic cracking reaction (liquefied gas + gasoline + diesel) increased by 0.99 percentage points, the coke yield decreased by 0.45 percentage points, the coke factor decreased, and the light olefin (ethylene + propylene + butene) yield increased by 2.8 percentage points, also showing excellent heavy oil conversion, reduced coke and more light olefins. And the additive is easy to use, small in dosage, and quick to take effect.

[0138] The results in Table 2 show that, compared with the comparative additives DCAT-1, DCAT-2 and DCAT-3, when the catalytic cracking additives CAT-1, CAT-2 and CAT-3 of the present invention are added to the LDC-200QH industrial catalyst, the catalytic cracking reaction conversion rate is improved, the heavy oil yield is reduced, the coke factor is reduced, the total liquid yield is increased, and the yield of light olefins (ethylene+propylene+butene) is increased. It is explained that when the additive provided by the present invention is used, the efficient conversion of heavy oil is promoted, the tendency to produce coke is reduced, and light olefins are produced more at the same time, and the selectivity of the catalytic cracking reaction is improved.

Claims

1. A catalytic cracking aid, which, based on 100% by weight of the catalytic cracking aid, comprises: 15-55% of ZSM-5 molecular sieve calculated on a dry basis, 0-55% of clay calculated on a dry basis, 1-15% of alumina nanofiber calculated on a dry basis, 1-10% of flaky aluminum phosphate calculated on a dry basis, 4-70% of a titanium-containing composite binder calculated on a dry basis, 0-10% of a binder calculated on an oxide basis, 5-20% of phosphorus calculated on an oxide basis, and 0-5% of a modified metal compound calculated on an oxide basis; in, The preparation method of the titanium-containing composite binder comprises the following steps: (1) mixing calcined clay, water and titanium tetrachloride solution to obtain a mixture; (2) reacting the above mixture at 40-120° C. for 0.5-6 hours to obtain the titanium-containing composite binder; Taking the dry basis of the titanium-containing composite binder as 100%, the composition of the titanium-containing composite binder comprises 7-45 wt % titanium calculated as oxide, 0.6-40 wt % aluminum calculated as oxide, and 30-92 wt % silicon calculated as oxide.

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

3. The catalytic cracking aid according to claim 1 or 2, wherein: The solid content of the titanium-containing composite binder is 10-45wt%; Preferably, based on 100% dry weight of the titanium-containing composite binder, the composition of the titanium-containing composite binder comprises 7-30 wt % titanium calculated as oxide, 8-40 wt % aluminum calculated as oxide, and 35-70 wt % silicon calculated as oxide.

4. The catalytic cracking aid according to claim 1 or 2, wherein: In the preparation method of the titanium-containing composite binder, the mixed raw materials also include a dispersant; based on the dry basis of the titanium-containing composite binder being 100%, the content of the dispersant is less than 10%.

5. The catalytic cracking aid according to claim 1 or 2, wherein: 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 in the preparation process of polypropylene catalyst.

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 a combination of two or more of kaolin, halloysite, montmorillonite, diatomaceous earth, halloysite, sepiolite and bentonite.

7. The catalytic cracking aid according to claim 1 or 2, wherein: In the preparation method of the titanium-containing composite binder, the calcination is performed at 400-900° C. for 0.5-6 h; Preferably, the preparation method of the titanium-containing composite binder comprises the following steps: mixing clay calcined at 550-850°C for 1-3h, water, and waste liquid containing titanium tetrachloride to form a mixture, heating the mixture to 60-120°C and reacting for 0.5-3h to obtain the titanium-containing composite binder.

8. The catalytic cracking aid according to claim 1 or 2, wherein: In the preparation method of the titanium-containing composite binder, after the reaction in step (2) is completed, the pH value of the reaction system is 0.5-8. Preferably, the pH value of the reaction system is adjusted to 0.5-8 by using an alkaline substance; Preferably, in step (1), the clay is crushed to an average particle size D(v, 0.5) < 4 μm before or after calcination, and then mixed with water and titanium tetrachloride solution.

9. The catalytic cracking aid according to claim 1 or 2, wherein: Calculated as oxide, the ZSM-5 molecular sieve contains 0.2-8% phosphorus and 0-5% of a second element, wherein the second element includes one or a combination of two or more of iron, zinc, magnesium, calcium, titanium, zirconium, lanthanum, cerium and yttrium.

10. The catalytic cracking aid according to claim 1 or 2, wherein: The clay includes one or a combination of two or more of kaolin, halloysite, montmorillonite, diatomaceous earth, halloysite, sepiolite and bentonite.

11. The catalytic cracking aid according to claim 1 or 2, wherein: The alumina nanofiber has a diameter of 20-50 nm, a length of 0.1-5 μm, and a specific surface area of ​​400 m 2 / g, pore volume ≥1.5cm 3 / g.

12. The catalytic cracking aid according to claim 1 or 2, wherein: The preparation method of the flaky aluminum phosphate is as follows: reacting an aluminum compound and a phosphorus compound at a molar ratio of P / Al=(2.6-3.4):1 at 40°C-90°C for 0.1-1h, then reacting at 120°C-170°C for 0.5-3h, drying, and calcining at 400°C-700°C for 0.5-3h to obtain the flaky aluminum phosphate.

13. The catalytic cracking aid according to claim 12, wherein: The aluminum compound includes one or a combination of two or more of aluminum oxide, aluminum hydroxide, aluminum sol, and pseudo-boehmite; The phosphorus compound includes one or a combination of two or more of phosphoric acid, phosphate, phosphorous acid, phosphite, pyrophosphoric acid, pyrophosphate, polyphosphoric acid, polyphosphate, metaphosphoric acid, and metaphosphate.

14. The catalytic cracking aid according to claim 1 or 2, wherein: The binder includes one or a combination of two or more of aluminum sol, silica sol, silica-alumina colloid, phosphate-alumina colloid, and acid-soluble pseudo-boehmite.

15. The catalytic cracking aid according to claim 14, wherein The acid-soluble pseudo-boehmite is prepared by adding acid to the pseudo-boehmite, and then aging at 40-90° C. for 0.5-3 hours for peptization before use; in the process of peptization of the pseudo-boehmite with acid, the acid is an inorganic acid.

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

17. The catalytic cracking aid according to claim 1 or 2, wherein: The composition of the catalytic cracking aid 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 aid; Preferably, the pore structure improver includes one or a combination of two or more of 1,3,5-trimethylbenzene, 1,3,5-triisopropylbenzene, methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, and polyethylene glycol.

18. The method for preparing the catalytic cracking aid according to any one of claims 1 to 17, comprising the following steps: (1) mixing and slurrying ZSM-5 molecular sieve, clay, alumina nanofibers, flaky aluminum phosphate, titanium-containing composite binder, binder, phosphorus compound, and modified metal compound to obtain a slurry; (2) spray-drying the slurry to form a shape, and then calcining and solidifying it to obtain the catalytic cracking aid; Preferably, the ZSM-5 molecular sieve is a mesoporous ZSM-5 molecular sieve.

19. The preparation method according to claim 18, wherein: The average particle size D (v, 0.5) of the slurry in step (2) is less than 4 μm.

Images