Antimetallic aids, process for their preparation and use

Abstract

This invention provides an anti-heavy metal additive, its preparation method, and its application. The anti-heavy metal additive comprises: 20%-60% magnesium oxide, 30%-75% aluminum oxide, and 5%-20% rare earth oxides; the magnesium oxide is provided by a first magnesium source and a magnesium-aluminum matrix material, and the aluminum oxide is provided by a first aluminum source and a magnesium-aluminum matrix material; the mass of the magnesium-aluminum matrix material is 5%-25% of the total mass of the raw materials of the anti-heavy metal additive; the magnesium-aluminum matrix material is obtained by crystallizing a mixture of a second magnesium source and a second aluminum source after sol-solution treatment, and the magnesium-aluminum matrix material comprises magnesium oxide and aluminum oxide in a mass ratio of 0.2-0.8:1. This invention also provides a preparation method and application of the above-mentioned additive. The above-mentioned anti-heavy metal additive can significantly improve the anti-heavy metal contamination performance of catalysts during catalytic cracking, exhibiting excellent coke selectivity and improved light oil yield.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalytic cracking of petroleum materials, and particularly relates to an anti-heavy metal additive and a preparation method and application thereof. BACKGROUND

[0002] With the development of oil refining industry and the improvement of oil refining technology, the raw materials processed by fluid catalytic cracking unit have changed significantly, and the catalytic cracking technology for atmospheric and vacuum heavy oil and residual oil is paid more and more attention. These raw materials usually have a high metal content, and some metal elements, especially nickel and vanadium, can cause the decrease of selectivity and the deactivation of catalyst, thereby affecting the properties and distribution of products and directly affecting the economic benefits of the refinery.

[0003] The catalytic cracking raw material contains various metals, and the vanadium element is the most harmful to the active center. It can damage the molecular sieve structure of the catalyst and cause poisoning, thereby affecting the catalytic activity. With the deepening of basic research work and the accumulation of experience, and the gradual deepening of the understanding of the internal related theoretical knowledge of the catalyst, the formula of the catalyst can be designed and the catalyst itself can be improved to meet various requirements in industrial applications. When the catalytic cracking raw oil is faced with heavy and poor quality, the variety of crude oil is increased, and atmospheric or vacuum residual oil and distillate oil from secondary processing are used as the raw material of FCC, resulting in the increasingly complex composition of the catalytic cracking raw material. Therefore, it is necessary to discuss the mechanism of the action of vanadium element on the catalyst and the deactivation thereof, and to study the corresponding solutions and prevention methods and measures.

[0004] Porphyrin nickel deposited on the catalyst is relatively stable in a reducing atmosphere and is completely decomposed at 500 DEG C for half an hour. In the high-temperature and oxidizing environment of the regenerator, the decomposition is accelerated (the decomposition temperature of porphyrin nickel in the oxidizing environment is 430-470 DEG C), and finally deposited on the catalyst in the form of an oxidized state. When the regenerated catalyst returns to the reactor, part of the high-valence nickel is easily reduced, and the valence of nickel changes between 0 and +2, and the dehydrogenation ability of nickel is in the order of Ni>Ni + >Ni 2+ . Since catalytic cracking is operated at atmospheric pressure, nickel mainly plays a dehydrogenation role to increase the hydrogen content in dry gas. Part of the catalytic feed and the dehydrogenated cracking products generate oily polycyclic aromatic polymer or coke, thereby reducing the liquid yield and making the selectivity of the catalyst worse. In addition, if the dehydrogenated products block the micropores of the catalyst and are not completely burned in the regeneration process, the surface area of the catalyst is reduced, and the cracking activity is affected.

[0005] The function of the nickel capturing agent is to make the nickel grains aggregate on the catalyst, reduce the active surface of nickel, or react with nickel to seal nickel in an inert spinel structure, thereby reducing its dehydrogenation carbon activity. Al2O3 with large grains and low surface area is usually introduced into the matrix of the catalyst, and the interaction between Al and Ni is greater than that between Si and Ni. The main role of Al is to form NiAl2O4 spinel, which seals nickel into the inert Ni-Al2O3 tetrahedral spinel structure.

[0006] Vanadium is deposited on the FCC catalyst through the following three steps:

[0007] 1. In the cracking stage, vanadium is deposited on the outer surface of the catalyst particles in the form of vanadium porphyrin with coke;

[0008] 2. In the regeneration stage, vanadium exists in the form of V2O5, which migrates to the entire surface of the catalyst due to its low melting point;

[0009] 3. Since V2O5 has a tendency to enrich the surface of the molecular sieve, it migrates from the matrix surface to the molecular sieve surface, thereby destroying the crystal structure of the molecular sieve.

[0010] In addition, under hydrothermal conditions, V2O5 deposited on the catalyst reacts with water vapor to form H3VO4;

[0011] V2O5(l) + 3H2O(g) → 2H3VO4(g)

[0012] H3VO4 attacks the molecular sieve by hydrolysis of the molecular sieve framework, causing the molecular sieve to be destroyed and permanently deactivated.

[0013] As mentioned earlier, vanadium attacks the molecular sieve, causing its crystalline structure to collapse and eventually deactivating it, so improving the gold resistance of the molecular sieve is important for improving the catalytic performance of the catalyst. In addition, the use of vanadium fixation agents in the matrix can fix vanadium deposited on the surface of the catalyst in the raw material, which can have a good passivation effect.

[0014] Inhibiting the migration of V2O5 to the molecular sieve phase and minimizing the generation of vanadic acid from V2O5 is the core of vanadium passivation, which can be achieved by the following methods.

[0015] (1) Let V2O5 react with vanadium passivation agents to form stable high-melting-point compounds, thereby inhibiting the migration of V2O5 to the molecular sieve phase and minimizing the generation of vanadic acid from V2O5. The current commonly used vanadium passivation mechanisms of rare earth, alkaline earth and tin can be represented as follows:

[0016] RE2O3 + V2O5 → 2REVO4

[0017] 2MgO + V2O5 → Mg2V2O7

[0018] The rare earth oxide is introduced into the catalytic cracking catalyst as a solid vanadium component, can form stable rare earth vanadate with vanadium, slow down the migration rate of vanadium and inhibit the destruction of the molecular sieve framework by vanadium.

[0019] The methods for solving heavy metal pollution mainly include: pretreatment of raw materials; use of catalysts resistant to heavy metal pollution; passivation or removal of contaminated metals on the equilibrium agent, etc. The main method for solving heavy metal pollution in China is to improve the anti-heavy metal pollution ability of the FCC catalyst itself and use metal passivators. It has been found that rare earth and vanadium can easily react under hydrothermal conditions to form stable compounds, and adding rare earth to the catalytic cracking catalyst can protect the molecular sieve structure.

[0020] In view of the situation caused by nickel, vanadium and other heavy metals pollution, a lot of research on improving the anti-heavy metal pollution ability of catalytic cracking catalyst has been reported in the prior art, such as introducing alkaline earth metals or rare earth elements during catalyst preparation to improve the anti-heavy metal pollution performance of the catalyst. These technologies are mostly direct addition during catalyst preparation or modification of molecular sieves and matrix components to improve the anti-heavy metal performance of the catalyst. Although these methods show certain anti-heavy metal pollution effect, when the nickel and vanadium content in the raw oil is high, the anti-pollution performance is limited, and only by increasing the catalyst addition amount, the product yield of the device can be maintained by large dosage.

[0021] Adding liquid metal passivator to the raw oil is also a common process operation method in catalytic cracking devices. For example, the widely used metal passivator with antimony and tin as effective components enters the reactor with the raw oil and reacts with harmful metals on the surface of the catalyst to slow down and inhibit the pollution of harmful metals to the catalyst. This action is to change the valence state and other forms of existence of the contaminated metal by forming new phases and lattice substitution with the contaminated metal, so as to achieve the purpose of passivation. The method of using metal passivators to reduce the pollution of harmful metals to the catalyst has the advantages of less investment, flexible operation, and has been widely used. In the preparation process of metal passivators, antimony and tin are usually used as effective components, but the use of this kind of metal passivator increases the difficulty of on-site management and also pollutes the working environment.

[0022] The microspherical catalytic cracking heavy metal resistant additive can be used in combination with the main catalyst or added alone, and is a flexible and remarkable operation process. For example, patent CN102019198A discloses a preparation and application of a bifunctional solid catalyst for resisting vanadium and nickel pollution in heavy oil cracking conversion process. The solid catalyst is prepared from lanthanum oxide, fine particle antimony oxide, Y molecular sieve and an alumina-based binder. However, the current microspherical catalytic cracking heavy metal resistant additive still has problems of low target product yield and high content of by-products, and the preparation of the heavy metal resistant additive needs to be improved. SUMMARY

[0023] In order to overcome the above problems, the purpose of the present application is to provide a heavy metal resistant additive and a preparation method and application thereof. The heavy metal resistant additive applied in the catalytic cracking process can resist nickel and vanadium pollution, significantly improve the heavy metal pollution resistance of the catalyst in the catalytic cracking process, and has excellent coke selectivity and the effect of improving light oil yield.

[0024] In order to achieve the above purpose, the present application provides a heavy metal resistant additive, which comprises, based on the total mass of the heavy metal resistant additive: 20-60% of magnesium oxide, 30-75% of aluminum oxide and 5-20% of rare earth oxide.

[0025] The magnesium oxide is provided by a first magnesium source and a magnesium-aluminum matrix material, and the aluminum oxide is provided by a first aluminum source and the magnesium-aluminum matrix material. The mass of the magnesium-aluminum matrix material on a dry basis accounts for 5-25% of the total mass of the raw materials of the heavy metal resistant additive on a dry basis.

[0026] The magnesium-aluminum matrix material is obtained by mixing a second magnesium source with a second aluminum source after peptization and crystallization. The magnesium-aluminum matrix material comprises magnesium oxide and aluminum oxide in a mass ratio of 0.2-0.8:1.

[0027] According to a specific embodiment of the present application, the mass ratio of the magnesium oxide in the heavy metal resistant additive is generally 20-60%, and can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60% and the like, or a range with any two of the above specific values as the end points.

[0028] According to a specific embodiment of the present application, the mass ratio of the aluminum oxide in the heavy metal resistant additive is generally 30-75%, for example, 35-75%, and can be 30%, 33%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% and the like, or a range with any two of the above specific values as the end points.

[0029] According to a specific embodiment of the present application, the rare earth oxide in the anti-heavy metal additive generally accounts for 5%-20% of the total mass of the anti-heavy metal additive, and can be 5%, 10%, 11%, 12%, 13%, 14%, 15%, 20%, etc. or a range defined by any two of the above values.

[0030] According to a specific embodiment of the present application, the first magnesium source can include a magnesium salt and / or magnesium oxide.

[0031] According to a specific embodiment of the present application, the first aluminum source can include pseudo-boehmite.

[0032] In the above anti-heavy metal additive, the rare earth oxide is introduced as a solid vanadium component, which can form stable rare earth vanadate with vanadium, slow down the migration rate of vanadium, and thus inhibit the damage of vanadium to the catalyst.

[0033] According to a specific embodiment of the present application, the rare earth element contained in the rare earth oxide can include a lanthanide series element. The lanthanide series element can specifically include one or a combination of two or more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

[0034] According to a specific embodiment of the present application, the second magnesium source includes magnesium oxide. In some specific embodiments, the second magnesium source can be ultra-fine magnesium oxide with a D(0.9) particle size of less than or equal to 2 μm. By using ultra-fine magnesium oxide to prepare the magnesium-aluminum matrix material, and then using the magnesium-aluminum matrix material to prepare the anti-heavy metal additive, the wear strength of the anti-heavy metal additive can be improved.

[0035] According to a specific embodiment of the present application, the second aluminum source includes pseudo-boehmite.

[0036] According to a specific embodiment of the present application, the dry basis mass of the magnesium-aluminum matrix material accounts for 5%-25% of the total dry basis mass of the raw materials of the anti-heavy metal additive, for example, 5%, 10%, 15%, 20%, 25%, etc. or a range defined by any two of the above values.

[0037] According to a specific embodiment of the present application, the magnesium-aluminum matrix material contains magnesium oxide and aluminum oxide in a mass ratio of 0.2-0.8:1. In some specific embodiments, the mass ratio of magnesium oxide and aluminum oxide in the magnesium-aluminum matrix material can be 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, etc. or a range defined by any two of the above values.

[0038] According to a specific embodiment of the present application, the second aluminum source can be subjected to peptization treatment before mixing with the second magnesium source; and the second magnesium source can form a colloidal system after mixing with the second aluminum source subjected to peptization treatment. Specifically, the method for preparing the magnesium-aluminum matrix material can include: mixing a slurry of the second aluminum source with an acidic substance to perform peptization treatment, and then mixing the slurry of the second aluminum source subjected to peptization treatment with a slurry of the second magnesium source to obtain a magnesium-aluminum colloidal slurry, and crystallizing to obtain the magnesium-aluminum matrix material.

[0039] In some specific embodiments, the mixing time of the slurry of the second aluminum source subjected to peptization treatment with the slurry of the second magnesium source can be controlled to be 0.5-1 h, and the mixing mode can be slurry mixing.

[0040] In the above method for preparing the magnesium-aluminum matrix material, the second aluminum source is combined with hydrogen ions (from the acidic substance) in a liquid environment and dissociates into a microcrystalline aluminum source with smaller particles, the hydroxyl groups of the microcrystalline aluminum source are combined with at least part of the second magnesium source, and after crystallization treatment, a stable magnesium-aluminum matrix material with crystal structure is formed.

[0041] In the above method for preparing the magnesium-aluminum matrix material, the acidic substance can be an inorganic acid, which can specifically include one or a combination of two or more of hydrochloric acid, nitric acid, formic acid, and acetic acid.

[0042] In the above method for preparing the magnesium-aluminum matrix material, the mass of the second aluminum source in terms of aluminum oxide, and the mass ratio of the acidic substance to the second aluminum source is generally controlled to be 0.10-0.5:1, further 0.10-0.25:1, for example, specific values such as 0.10:1, 0.15:1, 0.20:1, 0.25:1, 0.30:1, 0.35:1, 0.40:1, 0.45:1, 0.50:1, and ranges with any two of the above specific values as endpoints.

[0043] In the above method for preparing the magnesium-aluminum matrix material, when the acidic substance is an inorganic acid, a commercially available inorganic acid solution can be used, and thus the mass ratio of the acidic substance to the second aluminum source can also be the mass ratio of the mass of the commercially available inorganic acid solution to the mass of the second aluminum source. Specifically, when the acidic substance includes hydrochloric acid, the mass ratio of hydrochloric acid to the second aluminum source is the mass ratio of a hydrochloric acid solution with a mass concentration of 35-38% to the mass of the second aluminum source in terms of aluminum oxide; when the acidic substance includes nitric acid, the mass ratio of nitric acid to the second aluminum source is the mass ratio of a nitric acid solution with a mass concentration of 88% to the mass of the second aluminum source in terms of aluminum oxide; when the acidic substance includes formic acid, the mass ratio of formic acid to the second aluminum source is the mass ratio of a formic acid solution with a mass concentration of 88% to the mass of the second aluminum source in terms of aluminum oxide; and when the acidic substance includes acetic acid, the mass ratio of acetic acid to the second aluminum source is the mass ratio of an acetic acid solution with a mass concentration of 99% to the mass of the second aluminum source in terms of aluminum oxide.

[0044] In the method for preparing the magnesium-aluminum base material, the temperature for the peptization treatment is generally controlled to be 40-80°C, such as 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, and the like, and ranges defined by any two of the above-mentioned specific values as the end points.

[0045] In the method for preparing the magnesium-aluminum base material, the time for the peptization treatment is generally controlled to be 1h or more, such as 1h-3h.

[0046] In the method for preparing the magnesium-aluminum base material, the temperature for the crystallization is generally controlled to be 50-95°C, such as 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, and the like, and ranges defined by any two of the above-mentioned specific values as the end points.

[0047] In the method for preparing the magnesium-aluminum base material, the time for the crystallization is generally controlled to be 10-72h, such as 12h-72h, such as 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 50h, 55h, 60h, 65h, 70h, 72h, and the like, and ranges defined by any two of the above-mentioned specific values as the end points.

[0048] In the method for preparing the magnesium-aluminum base material, the crystallization can be one of static crystallization, dynamic crystallization, or intermittent dynamic crystallization.

[0049] In the method for preparing the magnesium-aluminum base material, the slurry of the second aluminum source can be formed by mixing the second aluminum source with water. The solid content of the slurry of the second aluminum source (the solid content in the present application is the mass content of the solid) can be 0.15-0.25, such as 0.15, 1.6, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, and the like, and ranges defined by any two of the above-mentioned specific values as the end points.

[0050] In the method for preparing the magnesium-aluminum base material, the slurry of the second magnesium source can be formed by mixing the second magnesium source with water. The solid content of the slurry of the second magnesium source is 0.2-0.4 (i.e. 20%-40%), such as 0.2, 0.25, 0.3, 0.35, 0.4, and the like, and ranges defined by any two of the above-mentioned specific values as the end points.

[0051] In the method for preparing the magnesium-aluminum matrix material, the raw material of the magnesium-aluminum matrix material can further include a surfactant, which is added to the uncrystallized magnesium-aluminum colloidal slurry. That is, the method for preparing the magnesium-aluminum matrix material can include: mixing a slurry of a second aluminum source with an acidic substance for peptization treatment, then mixing the peptized slurry of the second aluminum source with a slurry of a second magnesium source to obtain a magnesium-aluminum colloidal slurry, mixing the magnesium-aluminum colloidal slurry with a surfactant, and crystallizing to obtain the magnesium-aluminum matrix material.

[0052] In the method for preparing the magnesium-aluminum matrix material, the surfactant can include hexadecyl trimethyl ammonium bromide and / or hexadecyl trimethyl ammonium chloride.

[0053] In the method for preparing the magnesium-aluminum matrix material, the proportion of the mass of the surfactant to the total mass of the raw material of the magnesium-aluminum matrix material on a dry basis can be controlled to be 0.01-0.05:1, for example, can be 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, and the like, and ranges with any two of the above specific values as endpoints.

[0054] In the method for preparing the magnesium-aluminum matrix material, by adding the surfactant, the dispersion effect of the magnesium-aluminum colloidal can be improved. The surfactant can be micellized in an aqueous solution, reduce the interfacial tension between the two phases, and make the liquid and solid stably exist in water, showing effects such as emulsification and dispersion, thereby effectively reducing the particle size of the magnesium-aluminum matrix material and avoiding adverse effects on the particle strength and wear strength in the subsequent preparation of the heavy metal resistance aid.

[0055] The magnesium-aluminum matrix material provided by the present application can replace part of the aluminum source and part of the magnesium source in the raw material of the heavy metal resistance aid. By using the magnesium-aluminum matrix material, on the one hand, the structure of the heavy metal resistance aid can be optimized, so that the heavy metal resistance aid has a certain mesopore size and rich pore structure, and the adsorption effect of the heavy metal resistance aid on heavy metals such as nickel and vanadium is further improved; on the other hand, the viscosity of the system of peptized aluminum oxide and magnesium-containing substances in the preparation process of the heavy metal resistance aid can be reduced, the colloidal solid content of the raw material can be improved, and the product performance and production efficiency can be improved.

[0056] According to a specific embodiment of the present application, the raw material of the heavy metal resistance aid can further include 0-20% of clay, based on 100% of the dry mass of the heavy metal resistance aid. In some specific embodiments, the mass proportion of the clay in the heavy metal resistance aid can be 1%, 5%, 10%, 15%, 20%, and the like, and ranges with any two of the above specific values as endpoints. In the heavy metal resistance aid, the clay can exist in the form of an oxide.

[0057] According to a specific embodiment of the present application, the clay can specifically include one or a combination of two or more of kaolin, halloysite, montmorillonite, sepiolite, hydrotalcite, and rectorite.

[0058] According to a specific embodiment of the present application, the anti-heavy metal additive includes, based on the total mass of the anti-heavy metal additive raw material as 100%, 5-25% of a magnesium-aluminum matrix material, 0-20% of clay, and the balance of a rare earth source, a first magnesium source, and a first aluminum source. The first magnesium source, the first aluminum source, and the magnesium-aluminum matrix material are determined according to the content of magnesium oxide and aluminum oxide in the anti-heavy metal additive, and the rare earth source is determined according to the content of rare earth oxide in the anti-heavy metal additive.

[0059] The present application also provides a preparation method of the anti-heavy metal additive, which includes:

[0060] S1, mixing the first aluminum source and the rare earth source with an acidic substance for peptizing treatment to obtain a peptized product;

[0061] S2, mixing the peptized product obtained in S1 with the first magnesium source and the magnesium-aluminum matrix material to form a raw material colloid, drying, and calcining to obtain the anti-heavy metal additive.

[0062] In the preparation method of the anti-heavy metal additive, the rare earth source is used to provide rare earth elements in rare earth oxides, and the rare earth source can include soluble salts (such as nitrates) and / or oxides of rare earth elements, for example, can include soluble salts (such as nitrates) of lanthanide elements and / or oxides of lanthanide elements.

[0063] The preparation method of the present application can improve the bonding effect by using the aluminum-magnesium colloid formed by the aluminum source and the magnesium source and the bonding effect of the magnesium-aluminum matrix material, and does not need to add additional bonding agents in the preparation process, so that the raw material composition is simple and the cost is low.

[0064] In the preparation method of the anti-heavy metal additive, in S1, the temperature of the peptizing treatment is 50-80℃, for example, can be controlled to be 60-80℃. The temperature of the peptizing treatment can be specifically 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, and the like, and ranges with any two of the above specific values as endpoints.

[0065] In the preparation method of the anti-heavy metal additive, in S1, the time of the peptizing treatment can be controlled to be 0.5h-2h, for example, 0.5h-1h, and can be specifically 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1.0h, 1.5h, 2.0h, and the like, and ranges with any two of the above specific values as endpoints.

[0066] In the preparation method of the above anti-heavy metal additive, the acidic substance used in S1 can be an inorganic acid, which can specifically include one or a combination of two or more of hydrochloric acid, nitric acid, formic acid and acetic acid.

[0067] In the preparation method of the above anti-heavy metal additive, in S1, the mass ratio of the acidic substance to the first aluminum source is 0.10-0.25:1, based on the aluminum oxide content of the first aluminum source. Specifically, the mass ratio of the acidic substance to the first aluminum source can be 0.10:1, 0.15:1, 0.20:1, 0.25:1, and the like, as well as a range with any two of the above specific values as endpoints.

[0068] In the preparation method of the above anti-heavy metal additive, when the acidic substance is an inorganic acid, a commercially available inorganic acid solution can be used, and thus the mass ratio of the acidic substance to the first aluminum source can also be the mass ratio of the commercially available inorganic acid solution to the first aluminum source. Specifically, when the acidic substance includes hydrochloric acid, the mass ratio of the hydrochloric acid to the first aluminum source is the mass ratio of a hydrochloric acid solution with a mass concentration of 35-38% to the mass of the first aluminum source based on the aluminum oxide content; when the acidic substance includes nitric acid, the mass ratio of the nitric acid to the first aluminum source is the mass ratio of a nitric acid solution with a mass concentration of 88% to the mass of the first aluminum source based on the aluminum oxide content; when the acidic substance includes formic acid, the mass ratio of the formic acid to the first aluminum source is the mass ratio of a formic acid solution with a mass concentration of 88% to the mass of the first aluminum source based on the aluminum oxide content; and when the acidic substance includes acetic acid, the mass ratio of the acetic acid to the first aluminum source is the mass ratio of an acetic acid solution with a mass concentration of 99% to the mass of the first aluminum source based on the aluminum oxide content.

[0069] In the preparation method of the above anti-heavy metal additive, the colloidal product obtained in S1 can be in a colloidal form.

[0070] In the preparation method of the above anti-heavy metal additive, in S1, when the anti-heavy metal additive further includes clay, the clay is added together with the first aluminum source, the rare earth source and the acidic substance. That is, in this case, S1 includes mixing the first aluminum source, the rare earth source, the clay and the acidic substance to perform colloidal treatment, thereby obtaining a colloidal product.

[0071] In the preparation method of the above anti-heavy metal additive, in S2, the mixing time of the colloidal product obtained in S1 with the first magnesium source and the magnesium-aluminum substrate material can be 0.5-1 h. The mixing method can be slurry mixing.

[0072] In the preparation method of the above anti-heavy metal additive, in S2, the drying for facilitating molding can be spray drying. The spray drying process can use conventional parameters in the art. The average particle size of the particles obtained by spray drying can be 90-100 μm.

[0073] In the preparation method of the above anti-heavy metal adjuvant, in S2, the temperature of the calcination can be controlled to be 300-600 DEG C, for example, can be 300 DEG C, 350 DEG C, 400 DEG C, 450 DEG C, 500 DEG C, 550 DEG C, 600 DEG C and the like specific value and the range with any two of the above specific values as the end point.

[0074] In the preparation method of the above anti-heavy metal adjuvant, in S2, the time of the calcination can be controlled to be 0.5h-4h, for example, can be 0.5h, 1.0h, 1.5h, 2.0h, 2.5h, 3.0h, 3.5h, 4.0h and the like specific value and the range with any two of the above specific values as the end point.

[0075] The application also provides the application of the above anti-heavy metal adjuvant in catalytic cracking process. The anti-heavy metal adjuvant can resist nickel and vanadium pollution, and can be used as a dual-functional adjuvant for resisting nickel and vanadium pollution. The anti-heavy metal adjuvant can be added alone in the catalytic cracking device, or can be used in combination with the catalytic cracking catalyst, can effectively improve the yield of target products, reduce the yield of by-products such as dry gas and coke, and has a broad application prospect.

[0076] The application has the following beneficial effects:

[0077] 1. The anti-heavy metal adjuvant provided by the application is safe and environmentally friendly, the preparation process is simple, the operation is flexible in actual application, the anti-heavy metal pollution performance of the catalyst in the catalytic cracking process can be significantly improved, and the anti-heavy metal adjuvant can be used as a dual-functional adjuvant for resisting nickel and vanadium pollution. The anti-heavy metal adjuvant applied in the catalytic cracking process can reduce the yield of by-products such as dry gas and coke, has excellent coke selectivity, improve the light oil yield, can effectively improve the yield of target products, especially the yield of target products such as liquefied gas, is beneficial to maximize the benefit, has low cost, is convenient for industrial production, and has a broad application prospect.

[0078] 2. By introducing a specific magnesium-aluminum substrate material to replace part of the aluminum source and part of the magnesium source in the preparation process of the anti-heavy metal adjuvant, on the one hand, the viscosity of the raw material system in the preparation process of the adjuvant can be reduced, the colloidal solid content of the raw material can be improved, the product qualified rate and production efficiency can be improved; on the other hand, the wear resistance of the anti-heavy metal adjuvant can be improved, the structure of the adjuvant can be optimized, the pore structure of the adjuvant can be enriched, and the adsorption effect of the anti-heavy metal adjuvant on metal ions such as nickel and vanadium can be further improved. DETAILED DESCRIPTION

[0079] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the application, the technical solutions of the application will be described in detail below, but it cannot be understood as limiting the scope of the application.

[0080] In the following examples and comparative examples, the element content in the sample is determined by X-ray fluorescence analysis method.

[0081] The raw materials used in the examples and comparative examples of the present application are from the following sources and specifications.

[0082] Magnesium oxide, lanthanum nitrate, yttrium nitrate, lanthanum oxide, praseodymium chloride, hydrochloric acid, nitric acid, ammonium metavanadate, nickel nitrate, etc. are commercially available reagents of analytical purity.

[0083] Pseudo-boehmite (alumina content 62%): industrial product, Shanxi Aluminum Plant.

[0084] Kaolin: industrial product, provided by Lanzhou Petrochemical Catalyst Business Department.

[0085] Example 1

[0086] The present example provides an anti-heavy metal aid, and the preparation method thereof comprises:

[0087] (1) Preparation of magnesium-aluminum matrix material: take 161 grams of pseudo-boehmite, add 505 grams of deionized water, and add 10 grams of hydrochloric acid with a mass concentration of 36%-38% under continuous stirring, and heat to 40°C for 1 hour for peptization treatment to obtain a peptized pseudo-boehmite slurry; take 20 grams of magnesium oxide, add 50 grams of deionized water, mix uniformly, and then add the above peptized pseudo-boehmite slurry, and then add 1.2 grams of cetyltrimethylammonium bromide, and mix and stir for 30 minutes to obtain a magnesium-aluminum colloid slurry; transfer the above magnesium-aluminum colloid slurry to a crystallization reactor for crystallization reaction, and react at 50°C for 72 hours to obtain a magnesium-aluminum matrix material. The mass ratio of magnesium oxide to alumina in the material is 0.2:1.

[0088] (2) Preparation of anti-heavy metal aid: take 226 grams of pseudo-boehmite and 23 grams of lanthanum nitrate, add 501 grams of deionized water, and add 14 grams of hydrochloric acid with a mass concentration of 36%-38% under continuous stirring, and heat to 80°C for 30 minutes for peptization treatment; take 40 grams of magnesium oxide, add 160 grams of deionized water, mix uniformly, and then add the above peptized mixed slurry containing pseudo-boehmite and rare earth, and then add 33 grams of magnesium-aluminum matrix material slurry prepared in step (1) (the dry basis mass of the magnesium-aluminum matrix material is 5% of the total dry basis mass of the aid raw materials), mix and stir uniformly to form a raw material colloid; spray dry the raw material colloid to obtain particles with an average particle size of 90-100 μm, and then solidify and calcine at 300°C for 6h to obtain the anti-heavy metal aid.

[0089] The mass percentage of each component in the anti-heavy metal aid is as follows: magnesium oxide 21wt%, alumina 74wt%, and rare earth oxide 5wt%. The weight of the raw materials is based on the dry basis, and the mass of the magnesium-aluminum matrix material in the aid raw materials accounts for 5%.

[0090] The anti-heavy metal aid sample is denoted as S1. The physicochemical properties of the sample are shown in Table 1, and the reaction performance is shown in Table 2.

[0091] Example 2

[0092] The embodiment provides an anti-heavy metal aid, and a preparation method thereof comprises the following steps:

[0093] (1) Preparation of a magnesium-aluminum matrix material: 161 grams of pseudo-boehmite is taken, 339 grams of deionized water is added, 15 grams of hydrochloric acid with a mass concentration of 36%-38% is added under continuous stirring, and the temperature is increased to 50 DEG C for 1 hour for peptization treatment to obtain a peptized pseudo-boehmite slurry; 30 grams of magnesium oxide is taken, 45 grams of deionized water is added, and the mixture is uniformly mixed and then added into the peptized pseudo-boehmite slurry, and then 2.6 grams of cetyltrimethylammonium bromide is added, and the mixture is stirred for 30 minutes to obtain a magnesium-aluminum colloidal slurry; the magnesium-aluminum colloidal slurry is transferred to a crystallization reactor for crystallization reaction, and the temperature is kept at 95 DEG C for 10 hours to obtain the magnesium-aluminum matrix material. The mass ratio of magnesium oxide to aluminum oxide in the material is 0.3:1.

[0094] (2) Preparation of the anti-heavy metal aid: 97 grams of pseudo-boehmite and 23 grams of lanthanum nitrate are taken, 430 grams of deionized water is added, 7 grams of nitric acid with a mass concentration of 65%-68% is added under continuous stirring, and the temperature is increased to 50 DEG C for 60 minutes for peptization treatment; 110 grams of magnesium oxide is taken, 257 grams of deionized water is added, and the mixture is uniformly mixed and then added into the mixed slurry containing the pseudo-boehmite and rare earth after peptization treatment, and then 67 grams of the magnesium-aluminum matrix material prepared in step (1) (the dry basis mass of the magnesium-aluminum matrix material accounts for 10% of the total mass of the aid raw materials) is added, and the mixture is uniformly stirred to form a raw material colloid; the raw material colloid is subjected to spray drying to obtain particles with an average particle size of 90-100 microns, and the particles are solidified and calcined at 350 DEG C for 2 hours to obtain the anti-heavy metal aid.

[0095] The mass percentage of each component in the anti-heavy metal aid is as follows: 58wt% of magnesium oxide, 37wt% of aluminum oxide and 5wt% of rare earth oxide. The weight of the raw material is calculated on the basis of the dry basis, and the mass of the magnesium-aluminum matrix material in the aid raw materials accounts for 10%.

[0096] The anti-heavy metal aid sample is denoted as S2. The physicochemical properties of the sample are shown in Table 1, and the reaction performance is shown in Table 2.

[0097] Example 3

[0098] The embodiment provides an anti-heavy metal aid, and a preparation method thereof comprises the following steps:

[0099] (1) Preparation of magnesium-aluminum matrix material: Take 161 grams of pseudo-boehmite, add 239 grams of deionized water, and add 15 grams of hydrochloric acid with a mass concentration of 36%-38% under continuous stirring, heat to 60°C for 1 hour for peptization treatment to obtain a peptized pseudo-boehmite slurry; take 50 grams of magnesium oxide, add 75 grams of deionized water, mix well, and then add the above peptized pseudo-boehmite slurry, and then add 4.5 grams of cetyltrimethylammonium chloride, and mix and stir for 60 minutes to obtain a magnesium-aluminum colloidal slurry; transfer the above magnesium-aluminum colloidal slurry to a crystallization reactor for crystallization reaction, and react at 80°C for 24 hours to obtain a magnesium-aluminum matrix material. The mass ratio of magnesium oxide to aluminum oxide in the material is 0.5:1.

[0100] (2) Preparation of heavy metal resistance aid: Take 97 grams of pseudo-boehmite and 76 grams of cerium nitrate, add 133 grams of deionized water, and add 12 grams of hydrochloric acid with a mass concentration of 36%-38% under continuous stirring, heat to 60°C for 60 minutes for peptization treatment; take 60 grams of magnesium oxide, add 90 grams of deionized water, mix well, and then add the above peptized mixed slurry containing pseudo-boehmite, cerium, and vanadium, and then add 167 grams of the slurry of the magnesium-aluminum matrix material prepared in step (1) (the dry basis mass of the magnesium-aluminum matrix material is 25% of the total mass of the aid raw materials on a dry basis), mix and stir uniformly to form a raw colloid; spray dry the raw colloid to obtain particles with an average particle size of 90-100 μm, and then solidify and calcine at 400°C for 1 hour to obtain a heavy metal resistance aid.

[0101] The mass percentage of each component in the heavy metal resistance aid is: magnesium oxide 42.5 wt%, aluminum oxide 42.5 wt%, and rare earth oxide 15 wt%. The raw material weight is on a dry basis, and the mass of the magnesium-aluminum matrix material in the aid raw materials is 25%.

[0102] The heavy metal resistance aid sample is denoted as S3. The physicochemical properties of the sample are shown in Table 1, and the reaction performance is shown in Table 2.

[0103] Example 4

[0104] The present embodiment provides a heavy metal resistance aid, and a preparation method thereof includes:

[0105] (1) Preparation of magnesium-aluminum matrix material: take 161 grams of pseudo-boehmite, add 239 grams of deionized water, and add 15 grams of nitric acid with a mass concentration of 65%-68% under continuous stirring, heat to 60°C for 1 hour for peptization treatment to obtain a peptized pseudo-boehmite slurry; take 80 grams of magnesium oxide, add 187 grams of deionized water, mix well, and then add the above peptized pseudo-boehmite slurry, and then add 9 grams of cetyltrimethylammonium chloride, and mix and stir for 60 minutes to obtain a magnesium-aluminum colloidal slurry; transfer the above magnesium-aluminum colloidal slurry to a crystallization reactor for crystallization reaction at 90°C for 24 hours to obtain a magnesium-aluminum matrix material. The mass ratio of magnesium oxide to aluminum oxide in the material is 0.8:1.

[0106] (2) Preparation of heavy metal resistance aid: take 97 grams of pseudo-boehmite, 47 grams of kaolin, and 136 grams of yttrium nitrate, add 307 grams of deionized water, and add 12 grams of hydrochloric acid with a mass concentration of 36%-38% under continuous stirring, heat to 70°C for 60 minutes for peptization treatment; take 30 grams of magnesium oxide, add 45 grams of deionized water, mix well, and then add the above peptized mixed slurry containing pseudo-boehmite, rare earth, and clay, and then add 100 grams of the slurry of the magnesium-aluminum matrix material prepared in step (1) (the dry basis mass of the magnesium-aluminum matrix material is 15% of the total mass of the aid raw materials on a dry basis), mix and stir uniformly to form a raw colloidal material; spray dry the raw colloidal material to obtain particles with an average particle size of 90-100 μm, and then solidify and calcine at 500°C for 30 minutes to obtain a heavy metal resistance aid.

[0107] The mass percentage of each component in the heavy metal resistance aid is: 27wt% of magnesium oxide, 33wt% of aluminum oxide, 20wt% of rare earth oxide, and 20wt% of oxide formed by kaolin. The raw material weight is calculated on a dry basis, and the mass of the magnesium-aluminum matrix material in the aid raw materials accounts for 15%.

[0108] The heavy metal resistance aid sample is denoted as S4. The physicochemical properties of the sample are shown in Table 1, and the reaction performance is shown in Table 2.

[0109] Example 5

[0110] The embodiment provides a heavy metal resistance aid, and a preparation method thereof includes:

[0111] (1) Preparation of magnesium-aluminum matrix material: Take 161 grams of pseudo-boehmite, add 239 grams of deionized water, and add 20 grams of 65%-68% mass concentration nitric acid under continuous stirring, heat to 80°C for 1 hour for peptization treatment to obtain peptized pseudo-boehmite slurry; take 60 grams of magnesium oxide, add 140 grams of deionized water, mix well, and then add the above peptized pseudo-boehmite slurry, and then add 5 grams of cetyltrimethylammonium chloride, and mix and stir for 60 minutes to obtain a magnesium-aluminum colloidal slurry; transfer the above magnesium-aluminum colloidal slurry to a crystallization reactor for crystallization reaction at 90°C for 18 hours to obtain a magnesium-aluminum matrix material. The mass ratio of magnesium oxide to aluminum oxide in the material is 0.6:1.

[0112] (2) Preparation of heavy metal resistant additive: Take 129 grams of pseudo-boehmite, 24 grams of kaolin, and 102 grams of yttrium nitrate, add 283 grams of deionized water, and add 14 grams of 36%-38% mass concentration hydrochloric acid under continuous stirring, heat to 70°C for 60 minutes for peptization treatment; take 40 grams of magnesium oxide, add 65 grams of deionized water, mix well, and then add the above peptized mixed slurry containing pseudo-boehmite, rare earth, and clay, and then add 100 grams of the slurry of the magnesium-aluminum matrix material prepared in step (1) (the dry basis mass of the magnesium-aluminum matrix material is 15% of the total mass of the dry basis raw materials), mix and stir uniformly to form a raw material colloid; spray dry the raw material colloid to obtain particles with an average particle size of 90-100 μm, and then solidify and calcine at 600°C for 30 minutes to obtain a heavy metal resistant additive.

[0113] The mass percentage of each component in the heavy metal resistant additive is: magnesium oxide 29 wt%, aluminum oxide 46 wt%, rare earth oxide 15 wt%, and oxide formed from kaolin 10 wt%. The raw material weight is based on the dry basis, and the mass of the magnesium-aluminum matrix material in the raw material is 15%.

[0114] The heavy metal resistant additive sample is denoted as S5. The physicochemical properties of the sample are shown in Table 1, and the reaction performance is shown in Table 2.

[0115] Example 6

[0116] The present embodiment provides a heavy metal resistant additive, and the preparation method thereof comprises:

[0117] (1) Preparation of magnesium-aluminum matrix material: take 161 grams of pseudo-boehmite, add 339 grams of deionized water, and add 25 grams of hydrochloric acid with a mass concentration of 36%-38% under continuous stirring, and heat to 80°C for 1 hour for peptization treatment to obtain a peptized pseudo-boehmite slurry; take 50 grams of magnesium oxide, add 120 grams of deionized water, mix well, and then add the above peptized pseudo-boehmite slurry, and then add 6 grams of cetyltrimethylammonium chloride, and mix and stir for 60 minutes to obtain a magnesium-aluminum colloidal slurry; transfer the above magnesium-aluminum colloidal slurry to a crystallization reactor for crystallization reaction at 95°C for 48 hours to obtain a magnesium-aluminum matrix material. The mass ratio of magnesium oxide to aluminum oxide in the material is 0.5:1.

[0118] (2) Preparation of heavy metal resistance aid: take 97 grams of pseudo-boehmite and 43 grams of praseodymium chloride, add 298 grams of deionized water, and add 12 grams of hydrochloric acid with a mass concentration of 36%-38% under continuous stirring, and heat to 60°C for 60 minutes for peptization treatment; take 80 grams of magnesium oxide, add 149 grams of deionized water, mix well, and then add the above peptized mixed slurry containing pseudo-boehmite and rare earth, and then add 133 grams of the slurry of the magnesium-aluminum matrix material prepared in step (1) (the dry basis mass of the magnesium-aluminum matrix material is 20% of the total dry basis mass of the raw material), mix and stir uniformly to form a raw colloidal material; spray dry the raw colloidal material to obtain particles with an average particle size of 90-100 μm, and then solidify and calcine at 350°C for 120 minutes to obtain a heavy metal resistance aid.

[0119] The mass percentage of each component in the heavy metal resistance aid is: magnesium oxide 50wt%, aluminum oxide 40wt%, and rare earth oxide 10wt%. The raw material weight is based on the dry basis, and the mass of the magnesium-aluminum matrix material in the raw material is 20%.

[0120] The heavy metal resistance aid sample is denoted as S6. The physicochemical properties of the sample are shown in Table 1, and the reaction performance is shown in Table 2.

[0121] Example 7

[0122] The embodiment provides a heavy metal resistance aid, and a preparation method thereof includes:

[0123] (1) Preparation of magnesium-aluminum matrix material: Take 161 grams of pseudo-boehmite, add 257 grams of deionized water, and add 15 grams of nitric acid with a mass concentration of 65%-68% under continuous stirring, heat to 75°C for 1 hour for peptization treatment to obtain a peptized pseudo-boehmite slurry; take 60 grams of magnesium oxide, add 137 grams of deionized water, mix uniformly, and then add the above peptized pseudo-boehmite slurry, and then add 6 grams of cetyltrimethylammonium chloride, and mix and stir for 60 minutes to obtain a magnesium-aluminum colloidal slurry; transfer the above magnesium-aluminum colloidal slurry to a crystallization reactor for crystallization reaction at 95°C for 18 hours to obtain a magnesium-aluminum matrix material. The mass ratio of magnesium oxide to aluminum oxide in the material is 0.6:1.

[0124] (2) Preparation of heavy metal resistance aid: Take 113 grams of pseudo-boehmite and 65 grams of praseodymium chloride, add 323 grams of deionized water, and add 14 grams of formic acid with a mass concentration of 88% under continuous stirring, heat to 60°C for 60 minutes for peptization treatment; take 70 grams of magnesium oxide, add 130 grams of deionized water, mix uniformly, and then add the above peptized mixed slurry containing pseudo-boehmite and rare earth, and then add 100 grams of the slurry of the magnesium-aluminum matrix material prepared in step (1) (the dry basis mass of the magnesium-aluminum matrix material is 15% of the total mass of the dry basis raw materials), mix and stir uniformly to form a raw material colloid; spray dry the raw material colloid to obtain particles with an average particle size of 90-100 μm, and then solidify and calcine at 400°C for 30 minutes to obtain a heavy metal resistance aid.

[0125] The mass percentage of each component in the heavy metal resistance aid is: 44wt% of magnesium oxide, 41wt% of aluminum oxide, and 15wt% of rare earth oxide. The raw material weight is based on the dry basis, and the mass of the magnesium-aluminum matrix material in the raw material is 15%.

[0126] The heavy metal resistance aid sample is denoted as S7. The physicochemical properties of the sample are shown in Table 1, and the reaction performance is shown in Table 2.

[0127] Comparative Example 1

[0128] This comparative example provides a heavy metal resistance aid, and the preparation method thereof comprises:

[0129] Preparation of heavy metal resistance aid: take 145 grams of pseudo-boehmite and 68 grams of lanthanum nitrate, add 535 grams of deionized water, and add 18 grams of hydrochloric acid with a mass concentration of 36%-38% under continuous stirring, heat to 60°C for 60 minutes for peptization treatment; take 80 grams of magnesium oxide, add 453 grams of deionized water, mix uniformly, and then add the above peptized mixed slurry containing pseudo-boehmite and rare earth, mix and stir uniformly to form a raw material colloid; spray dry the raw material colloid to obtain particles with an average particle size of 90-100 μm, and then solidify and calcine at 400°C for 30 minutes to obtain a heavy metal resistance aid.

[0130] The anti-heavy metal additive comprises 40 wt% of magnesium oxide, 45 wt% of aluminum oxide, and 15 wt% of rare earth oxide.

[0131] The anti-heavy metal additive is denoted as D1. The physicochemical properties of the sample are shown in Table 1, and the reaction performance is shown in Table 2. Compared with the preparation method of the above examples, no magnesium-aluminum matrix material is added in the preparation of the anti-heavy metal additive.

[0132] Comparative Example 2

[0133] The anti-heavy metal additive is prepared by the following method:

[0134] Preparation of the anti-heavy metal additive: 103 grams of pseudoboehmite, 59 grams of lanthanum nitrate, and 35 grams of kaolin are added to 259 grams of deionized water, and 13 grams of hydrochloric acid with a mass concentration of 36%-38% is added under continuous stirring. The mixture is heated to 55°C and kept for 60 minutes for peptization treatment. 80 grams of magnesium oxide is added to 453 grams of deionized water, and the mixture is uniformly mixed and then added to the above-mentioned mixed slurry containing pseudoboehmite and rare earth after peptization treatment. The mixture is uniformly stirred to form a raw colloid. The raw colloid is subjected to spray drying to obtain particles with an average particle size of 90-100 μm. The particles are solidified and calcined at 450°C for 45 minutes to obtain the anti-heavy metal additive.

[0135] The anti-heavy metal additive comprises 40 wt% of magnesium oxide, 45 wt% of aluminum oxide, and 15 wt% of rare earth oxide.

[0136] The anti-heavy metal additive is denoted as D2. The physicochemical properties of the sample are shown in Table 1, and the reaction performance is shown in Table 2. Compared with the preparation method of the above examples, no magnesium-aluminum matrix material is added in the preparation of the anti-heavy metal additive.

[0137] Comparative Example 3

[0138] The anti-heavy metal additive is prepared by the following method:

[0139] (1) Preparation of the magnesium-aluminum matrix material: 161 grams of pseudoboehmite is added to 339 grams of deionized water, and 15 grams of hydrochloric acid with a mass concentration of 36%-38% is added under continuous stirring. The mixture is heated to 50°C and kept for 1 hour for peptization treatment to obtain a pseudoboehmite slurry after peptization. 30 grams of magnesium oxide is added to 45 grams of deionized water, and the mixture is uniformly mixed and then added to the above-mentioned pseudoboehmite slurry after peptization treatment. 2.6 grams of cetyltrimethylammonium bromide is further added, and the mixture is beaten and stirred for 30 minutes to obtain a magnesium-aluminum colloid slurry, which is ready for use. The mass ratio of magnesium oxide to aluminum oxide in the material is 0.3:1.

[0140] (2) Preparation of the heavy metal resistant additive: 97 grams of pseudoboehmite, 23 grams of lanthanum nitrate, and 430 grams of deionized water were taken, and 7 grams of nitric acid with a mass concentration of 65%-68% was added under continuous stirring, and the temperature was raised to 50°C for 60 minutes for peptization treatment; 110 grams of magnesium oxide was taken and added to 257 grams of deionized water, and then the mixed slurry containing pseudoboehmite and rare earth after peptization treatment was added, and then 67 grams of the magnesium-aluminum colloid slurry prepared in step (1) (the dry basis mass of the magnesium-aluminum colloid slurry was 10% of the total mass of the dry basis raw materials of the additive) was added, and the mixture was stirred uniformly to form a raw colloid; the raw colloid was spray dried to obtain particles with an average particle size of 90-100 μm, and then the particles were solidified and calcined at 350°C for 2 hours to obtain the heavy metal resistant additive.

[0141] The mass percentage of each component in the heavy metal resistant additive was as follows: 58 wt% of magnesium oxide, 37 wt% of aluminum oxide, and 5 wt% of rare earth oxide. The weight of the raw materials was calculated on a dry basis, and the mass of the magnesium-aluminum colloid slurry on a dry basis accounted for 10% of the total mass of the raw materials.

[0142] The heavy metal resistant additive sample was denoted as D3. The physicochemical properties of the sample were shown in Table 1, and the reaction performance was shown in Table 2. Compared with the preparation methods of the above examples, the heavy metal resistant additive was prepared by using uncrystallized magnesium-aluminum colloid slurry instead of magnesium-aluminum matrix material as the additive raw material.

[0143] Comparative Example 4

[0144] The present example provides a heavy metal resistant additive, and the preparation method thereof comprises the following steps:

[0145] (1) Preparation of the magnesium-aluminum matrix material: 161 grams of pseudoboehmite was taken and added to 339 grams of deionized water, and 25 grams of hydrochloric acid with a mass concentration of 36%-38% was added under continuous stirring, and the temperature was raised to 80°C for 1 hour for peptization treatment to obtain a peptized pseudoboehmite slurry; 50 grams of magnesium oxide was taken and added to 120 grams of deionized water, and then the peptized pseudoboehmite slurry was added, and then 6 grams of cetyltrimethylammonium chloride was added, and the mixture was stirred for 60 minutes to obtain a magnesium-aluminum colloid slurry; the magnesium-aluminum colloid slurry was transferred to a crystallization reactor for crystallization reaction at 70°C for 6 hours to obtain the magnesium-aluminum matrix material. The mass ratio of magnesium oxide to aluminum oxide in the material was 0.5:1.

[0146] (2) Preparation of the anti-heavy metal additive: 97 g of pseudoboehmite and 43 g of praseodymium chloride were taken, 298 g of deionized water was added, 12 g of hydrochloric acid with a mass concentration of 36%-38% was added under continuous stirring, and the colloidal sol treatment was carried out by heating to 60°C for 60 minutes; 80 g of magnesium oxide was taken, 149 g of deionized water was added, and the mixture was uniformly mixed and then added to the mixed slurry containing pseudoboehmite and rare earth after the colloidal sol treatment; then, 133 g of the magnesium-aluminum matrix material prepared in step (1) (the mass of the magnesium-aluminum matrix material is 20% of the dry basis mass of the additive raw material) was added, and the mixture was uniformly stirred to form a raw colloid; the raw colloid was spray dried to obtain particles with an average particle size of 90-100 μm, and then the particles were solidified and calcined at 350°C for 120 minutes to obtain the anti-heavy metal additive.

[0147] The mass percentage of each component in the anti-heavy metal additive is as follows: 50 wt% of magnesium oxide, 40 wt% of aluminum oxide, and 10 wt% of rare earth oxide. The weight of the raw material is based on the dry basis, and the mass of the magnesium-aluminum matrix material in the additive raw material is 20%. Compared with the preparation method of the magnesium-aluminum matrix material of the present application, the crystallization time in the preparation process of the magnesium-aluminum matrix material is shortened.

[0148] Test Example 1

[0149] (1) The solid content of the anti-heavy metal additive before spraying (i.e., the solid content of the raw colloid), the specific surface area, and the attrition index of each example and each comparative example were measured, and the results are shown in Table 1.

[0150] Table 1 Solid content of the anti-heavy metal additive before spraying, specific surface area, and attrition index

[0151]

[0152] (2) The performance of the anti-heavy metal additive of each example and each comparative example was evaluated as follows:

[0153] Preparation of the catalytic cracking catalyst: deionized water, kaolin, pseudoboehmite, and aluminum sol were mixed at room temperature to prepare a colloid, and then hydrochloric acid with a concentration of 36%-38% was added for colloidal sol treatment at a temperature of 60°C for 1 hour. After cooling, REUSY zeolite molecular sieves were added to prepare a slurry. The mass ratio of REUSY zeolite molecular sieves, pseudoboehmite, aluminum sol, and kaolin in the slurry was 32:15:8:45, the solid content of the slurry was 35%, and the amount of hydrochloric acid added was 15 wt% of the amount of pseudoboehmite added. The slurry was spray formed, the obtained catalyst was solidified and calcined at 450°C for 1 h, and then washed with an ammonium chloride solution at a temperature of 60°C, filtered, and dried to obtain the catalyst sample.

[0154] Preparation of vanadium pollution solution: 18.36 g of ammonium metavanadate was taken and added to 800 mL of deionized water, heated to dissolve in a 90 °C water bath, and transferred to a 1000 mL volumetric flask to make up to volume to obtain a vanadium solution of 8 g / L, which was used later.

[0155] Preparation of nickel pollution solution: 55.73 g of nickel nitrate was taken and added to 200 mL of deionized water, dissolved thoroughly, and transferred to a 250 mL volumetric flask to make up to volume to obtain a nickel pollution solution of 45 g / L, which was used later.

[0156] Method for catalyst pollution:

[0157] The catalyst to be polluted was dried in an oven at 120 °C for 4 hours, 100 g of the dried catalyst was taken and impregnated with an equal volume of the above-mentioned 75 mL vanadium pollution solution and 6.7 mL nickel pollution solution, and was left to stand, and was dried in an oven, and was then calcined in a muffle furnace at 500 °C for 2 h, and 5 g of the heavy metal resistant additive samples prepared in the examples and the comparative examples were added respectively, and were mixed uniformly to obtain a test catalytic cracking catalyst, which was used later.

[0158] Performance evaluation of the heavy metal resistant additive of the examples and the comparative examples:

[0159] The reaction performance of the catalytic cracking catalyst was evaluated by ACE. The catalytic cracking catalyst sample was placed in the reactor of ACE experiment, the reaction temperature was 530 °C, the regeneration temperature was 685 °C, the feed amount was 1.80 g, the cold trap temperature was -13.5 °C, and the agent oil ratio was 5.5, and the product distribution, conversion rate and the like after the reaction were analyzed and calculated, and the results are shown in Table 2.

[0160] Table 2 ACE evaluation results of the catalytic cracking catalyst (6000 ppm V, 3000 ppm Ni)

[0161]

[0162] As can be seen from Tables 1 and 2, by adding the magnesium-aluminum matrix material in the preparation process of the heavy metal resistant additive and controlling the preparation conditions of the magnesium-aluminum matrix material, the solid content of the colloidal system formed by the raw material of the heavy metal resistant additive can be improved, and the specific surface area and the anti-wear ability of the heavy metal resistant additive can be improved. The anti-nickel and vanadium pollution performance of the heavy metal resistant additive obtained in the catalytic cracking process is obviously improved, the coke selectivity is excellent, the light oil yield is improved, the target product yield (especially the yield of liquefied gas and other target products) is improved, the byproduct yield such as dry gas and coke is reduced, and the heavy metal resistant additive has a broad application prospect.

Claims

1. A heavy metal resistant additive, comprising, based on 100% of the total mass of the heavy metal resistant additive, the heavy metal resistant additive includes: Magnesium oxide 20%-60%, aluminum oxide 30%-75%, rare earth oxides 5%-20%; The magnesium oxide is provided by a first magnesium source and a magnesium-aluminum matrix material, and the alumina is provided by a first aluminum source and the magnesium-aluminum matrix material; the magnesium-aluminum matrix material, on a dry basis, constitutes 5%-25% of the total dry basis mass of the raw materials for the anti-heavy metal additives. The magnesium-aluminum matrix material is obtained by mixing a second magnesium source with a second aluminum source after sol-gel treatment and then crystallizing the mixture. The magnesium-aluminum matrix material includes magnesium oxide and aluminum oxide in a mass ratio of 0.2-0.8:

1. The crystallization temperature is 50-95℃ and the crystallization time is 10-72h.

2. The anti-heavy metal additive according to claim 1, wherein, The first magnesium source includes magnesium salts and / or magnesium oxide; The first aluminum source includes boehmite.

3. The anti-heavy metal additive according to claim 1, wherein, The second magnesium source includes magnesium oxide; The second aluminum source includes boehmite.

4. The anti-heavy metal additive according to claim 1, wherein, The preparation method of the magnesium-aluminum matrix material includes: mixing a slurry of a second aluminum source with an acidic substance for sol-gel treatment, then mixing the sol-gel treated slurry of the second aluminum source with a slurry of a second magnesium source to obtain a magnesium-aluminum colloidal slurry, crystallizing it, and obtaining the magnesium-aluminum matrix material.

5. The anti-heavy metal additive according to claim 4, wherein, The mass of the second aluminum source is calculated as alumina, and the mass ratio of the acidic substance to the second aluminum source is 0.10-0.5:

1.

6. The anti-heavy metal additive according to claim 4, wherein, The temperature of the gelation treatment is 40-80℃, and the time of the gelation treatment is more than 1 hour.

7. The anti-heavy metal additive according to claim 4, wherein, The raw materials for the magnesium-aluminum matrix material also include surfactants, which are added to the uncrystallized magnesium-aluminum colloidal slurry.

8. The anti-heavy metal additive according to claim 7, wherein, The surfactant includes hexadecyltrimethylammonium bromide and / or hexadecyltrimethylammonium chloride.

9. The anti-heavy metal additive according to claim 7, wherein, The ratio of the mass of the surfactant to the total mass of the raw materials of the magnesium-aluminum matrix material on a dry basis is 0.01-0.05:

1.

10. The anti-heavy metal additive according to claim 1, wherein, The rare earth oxides contain rare earth elements including lanthanides.

11. The anti-heavy metal additive according to any one of claims 1-10, wherein, Based on a dry basis of 100% of the raw materials for the anti-heavy metal additive, the raw materials for the anti-heavy metal additive also include 0-20% clay.

12. The anti-heavy metal additive according to claim 11, wherein, The clay includes one or more of the following: kaolin, halloysite, montmorillonite, sepiolite, hydrotalcite, and rettoite.

13. A method for preparing the anti-heavy metal additive according to any one of claims 1-12, the method comprising: S1. The first aluminum source, rare earth source and acidic substance are mixed and subjected to sol-gel treatment to obtain sol-gel product; S2. The sol product obtained in S1 is mixed with the first magnesium source and magnesium-aluminum matrix material to form a raw material colloid, dried, and calcined to obtain the anti-heavy metal additive.

14. The preparation method according to claim 13, wherein, In S1, the temperature of the sol-gel treatment is 50-80℃, and the time of the sol-gel treatment is 0.5h-2h.

15. The preparation method according to claim 13, wherein, In S1, the mass of the first aluminum source is based on aluminum oxide, and the mass ratio of the acidic substance to the first aluminum source is 0.10-0.25:

1.

16. The application of the anti-heavy metal additive according to any one of claims 1-12 in the catalytic cracking process.

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