Heavy metal resistant auxiliary agent as well as preparation method and application thereof

Abstract

The invention provides a heavy metal resistant auxiliary agent as well as a preparation method and application thereof. The heavy metal resistant auxiliary agent comprises 20%-60% of magnesium oxide, 30%-75% of aluminum oxide and 5%-20% of rare earth oxide; the magnesium oxide is provided by the first magnesium source and the magnesium-aluminum matrix material, and the aluminum oxide is provided by the first aluminum source and the 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 heavy metal resistant auxiliary agent; the magnesium-aluminum matrix material is obtained by mixing and crystallizing a second magnesium source and a second aluminum source subjected to peptizing treatment, and the magnesium-aluminum matrix material comprises magnesium oxide and aluminum oxide in a mass ratio of (0.2-0.8): 1. The invention also provides a preparation method and application of the additive. The heavy metal resistant auxiliary agent can significantly improve the heavy metal pollution resistance of the catalyst in the catalytic cracking process, and has the effects of excellent coke selectivity and light oil yield improvement.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum catalytic cracking materials, and in particular to an anti-heavy metal additive and a preparation method and application thereof. Background Art

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

[0003] Catalytic cracking feedstock contains a variety of metals, among which vanadium is the most harmful to the active center. It will destroy the molecular sieve structure of the catalyst, poison it, and thus affect the catalytic activity. With the deepening of basic research work and the accumulation of experience, and the gradual deepening of the understanding of the intrinsic theoretical knowledge of the catalyst, it has been possible to design the catalyst formula and improve the catalyst itself in a more targeted manner to meet various requirements in industrial applications. When the catalytic cracking feedstock oil is facing the heavy and inferior quality, the increase in crude oil varieties, atmospheric or vacuum residue oil and secondary processed distillate oil as FCC raw materials, the composition of the catalytic cracking feedstock is becoming more and more complex. Therefore, it is very necessary to discuss the role of vanadium and the catalyst and the mechanism that leads to its deactivation, and to study the corresponding solutions and prevention methods and measures.

[0004] The porphyrin nickel deposited on the catalyst is relatively stable in a reducing atmosphere and takes half an hour to completely decompose at 500°C. The decomposition is accelerated in the high temperature and oxidizing environment of the regenerator (the decomposition temperature of porphyrin nickel in an oxidizing environment is 430-470°C), and it is finally deposited on the catalyst in an oxidized state. When the regenerated catalyst returns to the reactor, part of the high-valent nickel oxide is easily reduced. The valence of nickel changes between 0 and +2 with the alternation of the reaction and regeneration process. The order of its dehydrogenation capacity is Ni>Ni + >Ni 2+ . Since catalytic cracking is operated at normal pressure, nickel mainly plays a dehydrogenation role, increasing the hydrogen content in the dry gas. After dehydrogenation, part of the catalytic feed and cracking products generate oily polycyclic aromatic hydrocarbon polymers or coke, which leads to a decrease in liquid yield and poor catalyst selectivity. In addition, if the dehydrogenated products block the micropores of the catalyst and are not completely burned during the regeneration process, the surface area of ​​the catalyst will be reduced, affecting its cracking activity.

[0005] The role of the nickel trap is to aggregate nickel grains on the catalyst, reduce the active surface of nickel, or react with nickel to seal nickel in a certain inert spinel structure, thereby reducing its dehydrogenation carbonization activity. Large-grained, low-surface-area Al2O3 is usually introduced into the matrix of the catalyst. The interaction between Al-Ni is greater than that between Si-Ni. The role of Al is mainly to form NiAl2O4 spinel, sealing nickel in the inert Ni-Al2O3 tetrahedral spinel structure.

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

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

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

[0009] 3. Since V2O5 has a tendency to be enriched on the surface of the molecular sieve, it migrates from the surface of the substrate to the surface of the molecular sieve, 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 hydrolyzing the molecular sieve framework, destroying the molecular sieve and making it permanently inactive.

[0013] As mentioned above, vanadium will attack the molecular sieve, causing its crystal to collapse and eventually deactivate, so improving the metal resistance of the molecular sieve is important for improving the catalytic performance of the catalyst. In addition, using a vanadium fixer in the matrix to fix the vanadium deposited on the catalyst surface in the raw material 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 are the core of vanadium passivation, which can be achieved through the following methods.

[0015] (1) Allow V2O5 to react with the vanadium passivation agent to generate a stable high melting point compound, thereby inhibiting the migration of V2O5 to the molecular sieve phase and minimizing the generation of vanadic acid from V2O5. The currently commonly used rare earth, alkaline earth and tin-based vanadium passivation mechanisms can be expressed as follows:

[0016] RE2O3+V2O5→2REVO4

[0017] 2MgO+V2O5→Mg2V2O7

[0018] Rare earth oxides are introduced into catalytic cracking catalysts as vanadium-fixing components, and can form stable rare earth vanadates with vanadium, slowing down the migration rate of vanadium and thus inhibiting the destruction of vanadium to the molecular sieve framework.

[0019] The main methods to solve heavy metal pollution are: pre-treatment of raw materials; use of catalysts resistant to heavy metal pollution; passivation or removal of polluted metals on the balance agent, etc. The main method to solve heavy metal pollution in China is to improve the resistance of FCC catalysts to heavy metal pollution and use metal passivators. At present, studies have found that rare earth and vanadium can easily react to form stable compounds under hydrothermal conditions. Adding rare earth to catalytic cracking catalysts can protect the molecular sieve structure.

[0020] In view of the situation caused by heavy metal pollution such as nickel and vanadium, a large number of reports in the prior art have been made on various improvements to catalytic cracking catalysts to improve their ability to resist heavy metal pollution. For example, alkaline earth metals or rare earth elements can be introduced during the catalyst preparation process to improve the heavy metal pollution resistance of the catalyst. Most of these technologies directly add or modify molecular sieves and matrix components during the catalyst preparation process to improve the heavy metal resistance of the catalyst. Although these methods have shown a certain effect of resisting heavy metal pollution, when the nickel and vanadium content in the crude oil is high, its anti-pollution performance is limited, and the product yield of the device can only be maintained by increasing the amount of catalyst added in a large dosage consumption manner.

[0021] Adding liquid metal passivators to the crude oil is also a common process operation method in catalytic cracking units. For example, the widely used metal passivators with antimony and tin as effective components enter the reactor with the crude oil and react with harmful metals on the catalyst surface to reduce and inhibit the pollution of the catalyst by harmful metals. This effect is to change the valence state and other forms of existence of the polluting metal by generating new phases with the polluting metal and undergoing lattice substitution, thereby achieving the purpose of passivation. The method of using metal passivators to reduce the pollution of the catalyst by harmful metals has low investment and flexible operation and has been widely adopted. Antimony and tin are usually used as effective components in the preparation process of metal passivators, but the use of such metal passivators increases the difficulty of on-site management and pollutes the working environment.

[0022] The use of microsphere catalytic cracking heavy metal resistance additives can be used in combination with the main catalyst or added separately. It is a flexible and effective operation process. For example, patent CN102019198A discloses the preparation and application of a bifunctional solid catalyst for heavy oil cracking and conversion that is resistant to vanadium and nickel pollution. The solid catalyst is prepared from lanthanum oxide, fine-grained antimony oxide, Y molecular sieve and alumina-based binder. However, the current microsphere catalytic cracking heavy metal resistance additives still have the problems of low target product yield and high by-product content, and the preparation of heavy metal resistance additives needs to be improved. Summary of the invention

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

[0024] In order to achieve the above object, the present invention provides an anti-heavy metal additive, which comprises: 20%-60% magnesium oxide, 30%-75% aluminum oxide, and 5%-20% rare earth oxide, based on the total mass of the anti-heavy metal additive being 100%;

[0025] Wherein, 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 is 5%-25% of the total mass of the raw materials of the anti-heavy metal 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 treatment and then crystallizing the mixture. 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 invention, the mass proportion of magnesium oxide in the anti-heavy metal additive is generally 20%-60%, and can be specifically 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60% and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0028] According to a specific embodiment of the present invention, the mass proportion of aluminum oxide in the anti-heavy metal additive is generally 30%-75%, for example 35%-75%, and specifically can be 30%, 33%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0029] According to a specific embodiment of the present invention, the mass proportion of the rare earth oxide in the anti-heavy metal additive is generally 5%-20%, and can be specifically 5%, 10%, 11%, 12%, 13%, 14%, 15%, 20% and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

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

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

[0032] In the above-mentioned heavy metal resistance additives, rare earth oxides are introduced as vanadium-fixing components, which can form stable rare earth vanadates 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 invention, the rare earth element contained in the rare earth oxide may include a lanthanide element. The lanthanide element may 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 invention, the second magnesium source includes magnesium oxide. In some specific embodiments, the second magnesium source can be ultrafine magnesium oxide, and the particle size D(0.9) of the ultrafine magnesium oxide is less than or equal to 2 μm. By using ultrafine magnesium oxide to prepare a magnesium-aluminum matrix material, and then using the magnesium-aluminum matrix material to prepare an 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 invention, the second aluminum source includes pseudo-boehmite.

[0036] According to a specific embodiment of the present invention, on a dry basis, the dry basis mass of the magnesium-aluminum matrix material is 5%-25% of the total mass of the dry basis of the raw materials of the anti-heavy metal additive, for example, 5%, 10%, 15%, 20%, 25% and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0037] According to a specific embodiment of the present invention, 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 to 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 and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0038] According to a specific embodiment of the present invention, the second aluminum source can be first subjected to peptization treatment and then mixed with the second magnesium source; the second magnesium source can form a colloidal system after being mixed with the second aluminum source subjected to peptization treatment. Specifically, the method for preparing the magnesium-aluminum matrix material may include: mixing a slurry of the second aluminum source with an acidic substance for peptization treatment, then mixing the slurry of the second aluminum source after peptization treatment with the 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 after peptization treatment and the slurry of the second magnesium source can be controlled to be 0.5h-1h, and the mixing method can be slurry mixing.

[0040] In the above-mentioned method for preparing the magnesium-aluminum matrix material, the second aluminum source combines with hydrogen ions (from acidic substances) in the liquid environment and dissociates into smaller particles of microcrystalline aluminum source. The hydroxyl groups of the microcrystalline aluminum source then combine with at least part of the second magnesium source and undergo crystallization treatment to form a stable magnesium-aluminum matrix material with a crystalline structure.

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

[0042] In the above-mentioned method for preparing the magnesium-aluminum matrix material, 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 usually controlled to be 0.10-0.5:1, further to 0.10-0.25:1, for example, 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 other specific values, as well as a range with any two of the above-mentioned specific values ​​as endpoints.

[0043] In the preparation method of the above-mentioned magnesium-aluminum matrix material, when the acidic substance is an inorganic acid, a commercially available inorganic acid solution can be used, and the mass ratio of the acidic substance to the second aluminum source can also be the 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 ratio of the second aluminum source calculated as 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 ratio of the second aluminum source calculated as 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 ratio of the second aluminum source calculated as aluminum oxide; 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 ratio of the second aluminum source calculated as aluminum oxide.

[0044] In the preparation method of the above-mentioned magnesium-aluminum matrix material, the temperature of the peptization treatment is usually controlled to be 40-80°C, for example, specific values ​​such as 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, and a range with any two of the above-mentioned specific values ​​as endpoints.

[0045] In the above-mentioned method for preparing the magnesium-aluminum matrix material, the peptization treatment time is usually controlled to be more than 1 hour, for example, 1 hour to 3 hours.

[0046] In the preparation method of the above-mentioned magnesium-aluminum matrix material, the crystallization temperature is usually controlled to be 50-95°C, for example, specific values ​​such as 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, and ranges with any two of the above-mentioned specific values ​​as endpoints.

[0047] In the preparation method of the above-mentioned magnesium-aluminum matrix material, the crystallization time is 10-72h, and can further be 12h-72h. For example, it can be 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 50h, 55h, 60h, 65h, 70h, 72h and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0048] In the above-mentioned method for preparing the magnesium-aluminum matrix material, the crystallization method may be static crystallization, dynamic crystallization or intermittent dynamic crystallization.

[0049] In the above-mentioned method for preparing the magnesium-aluminum matrix 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 invention is the mass content of the solid) can be 0.15-0.25, for example, 0.15, 1.6, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25 and other specific values ​​and ranges with any two of the above specific values ​​as endpoints.

[0050] In the above-mentioned method for preparing the magnesium-aluminum matrix 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%), for example, it can be 0.2, 0.25, 0.3, 0.35, 0.4 and other specific values, and a range with any two of the above specific values ​​as endpoints.

[0051] In the above-mentioned method for preparing the magnesium-aluminum matrix material, the raw material of the magnesium-aluminum matrix material may further include a surfactant, and the surfactant is added to the uncrystallized magnesium-aluminum colloidal slurry. That is, the method for preparing the magnesium-aluminum matrix material may include: mixing the slurry of the second aluminum source with an acidic substance for peptization treatment, then mixing the peptized second aluminum source slurry with the second magnesium source slurry 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 above method for preparing the magnesium-aluminum matrix material, the surfactant may include hexadecyltrimethylammonium bromide and / or hexadecyltrimethylammonium chloride.

[0053] In the preparation method of the above-mentioned magnesium-aluminum matrix material, 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 can be controlled to be 0.01-0.05:1, for example, it can be specific values ​​such as 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, and a range with any two of the above-mentioned specific values ​​as endpoints.

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

[0055] The above-mentioned magnesium-aluminum matrix material provided by the present invention can replace part of the aluminum source and part of the magnesium source in the raw material of the anti-heavy metal additive. By adopting the magnesium-aluminum matrix material, on the one hand, the structural optimization of the anti-heavy metal additive can be achieved, so that the anti-heavy metal additive has a certain mesopore diameter, enriches the pore structure of the anti-heavy metal additive, and further improves the adsorption effect of the anti-heavy metal additive on heavy metals such as nickel and vanadium; on the other hand, the viscosity of the system of peptized alumina and magnesium-containing substances in the preparation process of the anti-heavy metal additive can be reduced, the solid content of the raw material colloid can be increased, and the product performance and production efficiency can be improved.

[0056] According to a specific embodiment of the present invention, the raw materials of the anti-heavy metal additive may further include 0-20% clay, based on the dry basis mass of the anti-heavy metal additive being 100%. In some specific embodiments, the mass proportion of the clay in the anti-heavy metal additive may be 1%, 5%, 10%, 15%, 20%, and other specific values, as well as a range with any two of the above specific values ​​as endpoints. In the anti-heavy metal additive, the clay may be present in the form of an oxide.

[0057] According to a specific embodiment of the present invention, the clay may 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 invention, based on the total dry weight of the anti-heavy metal additive raw material as 100%, the anti-heavy metal additive includes: 5-25% of magnesium-aluminum matrix material, 0-20% of clay, and the balance is rare earth source, first magnesium source and first aluminum source. Among them, 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 invention also provides a method for preparing the above-mentioned heavy metal resistance additive, which comprises:

[0060] S1, mixing a first aluminum source, a rare earth source and an acidic substance for peptization treatment to obtain a peptization 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 roasting to obtain the anti-heavy metal additive.

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

[0063] The preparation method of the present invention can improve the bonding effect by utilizing the bonding effect of the aluminum-magnesium colloid formed by the aluminum source and the magnesium source and the magnesium-aluminum matrix material. No additional binder needs to be added during the preparation process, and the raw material composition is simple and the cost is low.

[0064] In the preparation method of the above-mentioned heavy metal resistance additive, in S1, the temperature of the peptization treatment is 50-80° C., for example, it can be controlled to be 60-80° C. The temperature of the peptization treatment can be specifically 50° C., 55° C., 60° C., 65° C., 70° C., 75° C., 80° C., and a range with any two of the above-mentioned specific values ​​as endpoints.

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

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

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

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

[0069] In the above method for preparing the heavy metal resistance additive, the peptized product obtained in S1 may be in a colloid form.

[0070] In the above-mentioned preparation method of the heavy metal resistance additive, in S1, when the heavy metal resistance additive further includes clay, the clay is added together with the first aluminum source, the rare earth source, and the acidic substance. That is, at this time, S1 includes: mixing the first aluminum source, the rare earth source, the clay, and the acidic substance for peptization treatment to obtain a peptized product.

[0071] In the above-mentioned preparation method of the heavy metal resistance additive, in S2, the peptized product obtained in S1 and the first magnesium source and the magnesium-aluminum matrix material can be mixed for 0.5 h to 1 h, and the mixing method can be beating mixing.

[0072] In the above-mentioned preparation method of the heavy metal resistance additive, in S2, the drying is used to promote molding, and spray drying can be used. The spray drying process can adopt conventional conditions and 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-mentioned anti-heavy metal additive, in S2, the roasting temperature can be controlled to be 300-600°C, for example, it can be specific values ​​such as 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, and a range with any two of the above-mentioned specific values ​​as endpoints.

[0074] In the preparation method of the above-mentioned anti-heavy metal additive, in S2, the roasting time can be controlled to be 0.5h-4h, for example, it can be specific values ​​such as 0.5h, 1.0h, 1.5h, 2.0h, 2.5h, 3.0h, 3.5h, 4.0h, and a range with any two of the above-mentioned specific values ​​as endpoints.

[0075] The present invention also provides the use of the heavy metal resistant additive in a catalytic cracking process. The heavy metal resistant additive can resist nickel and vanadium pollution and can be used as a nickel-vanadium resistant bifunctional additive. It can be added alone in a catalytic cracking unit or used in combination with a catalytic cracking catalyst, which can effectively improve the yield of the target product and reduce the yield of byproducts such as dry gas and coke, and has broad application prospects.

[0076] The beneficial effects of the present invention are:

[0077] 1. The heavy metal resistance additive provided by the present invention is safe and environmentally friendly, has a simple preparation process, is flexible in operation in practical applications, can significantly improve the heavy metal pollution resistance of the catalyst in the catalytic cracking process, and can be used as a bifunctional additive for resisting nickel and vanadium pollution. The heavy metal resistance additive is applied in the catalytic cracking process to reduce the yield of by-products such as dry gas and coke, has excellent coke selectivity, improves the light oil yield, and can effectively improve the yield of target products, especially the yield of target products such as liquefied gas, which is conducive to maximizing benefits, has low cost, is convenient for industrial production, and has broad application prospects.

[0078] 2. The present invention introduces a specific magnesium-aluminum matrix material to replace part of the aluminum source and part of the magnesium source during the preparation process of the anti-heavy metal additive. On the one hand, it can reduce the viscosity of the raw material system during the preparation process of the additive, increase the solid content of the raw material colloid, and improve the product qualification rate and production efficiency; on the other hand, it can improve the wear strength of the anti-heavy metal additive, optimize the structure of the additive, enrich the pore structure of the additive, and further improve the adsorption effect of the anti-heavy metal additive on metal ions such as nickel and vanadium. DETAILED DESCRIPTION

[0079] 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.

[0080] In the following examples and comparative examples, the element contents in the samples were determined by X-ray fluorescence analysis.

[0081] Origin and specifications of raw materials used in the examples and comparative examples of the present invention.

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

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

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

[0085] Example 1

[0086] This embodiment provides an anti-heavy metal additive, and the preparation method thereof includes:

[0087] (1) Preparation of magnesium-aluminum matrix material: 161 grams of pseudo-boehmite was taken, 505 grams of deionized water was added, 10 grams of hydrochloric acid with a mass concentration of 36%-38% was added under continuous stirring, and the temperature was raised to 40°C and maintained for 1 hour for peptization treatment to obtain peptized pseudo-boehmite slurry; 20 grams of magnesium oxide was taken, 50 grams of deionized water was added, and the mixture was evenly mixed and added to the peptized pseudo-boehmite slurry, and then 1.2 grams of hexadecyltrimethylammonium bromide was added, and the mixture was beaten and stirred for 30 minutes to obtain magnesium-aluminum colloidal slurry; the magnesium-aluminum colloidal slurry was transferred to a crystallization reactor for crystallization reaction, and the reaction was carried out at 50°C for 72 hours to obtain a magnesium-aluminum matrix material. The mass ratio of magnesium oxide to aluminum oxide in the material is 0.2:1.

[0088] (2) Preparation of heavy metal resistance additive: Take 226 grams of pseudo-boehmite and 23 grams of lanthanum nitrate, add 501 grams of deionized water, 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 well, and add to the mixed slurry containing pseudo-boehmite and rare earth after the peptization treatment, and then add 33 grams of the slurry of magnesium aluminum matrix material prepared in step (1) (the dry basis mass of magnesium aluminum matrix material is 5% of the total dry basis mass of the additive raw material), mix and stir well 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 cure and roast at 300°C for 6 hours to obtain the heavy metal resistance additive.

[0089] The weight percentage of each component in the heavy metal resistance additive is: 21wt% of magnesium oxide, 74wt% of aluminum oxide, and 5wt% of rare earth oxide. The weight of the raw materials is calculated on a dry basis, and the weight proportion of magnesium-aluminum matrix material in the additive raw materials is 5%.

[0090] The heavy metal resistance additive sample is denoted as S1. The physical and chemical properties of the samples are shown in Table 1, and the reaction properties are shown in Table 2.

[0091] Example 2

[0092] This embodiment provides an anti-heavy metal additive, and the preparation method thereof includes:

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

[0094] (2) Preparation of heavy metal resistance additive: 97 g of pseudo-boehmite and 23 g of lanthanum nitrate are added to 430 g of deionized water, and 7 g of nitric acid with a mass concentration of 65%-68% is added under continuous stirring, and the temperature is raised to 50°C and maintained for 60 minutes for peptization treatment; 110 g of magnesium oxide is added to 257 g of deionized water, and the mixture is mixed evenly, and then added to the mixed slurry containing pseudo-boehmite and rare earth after the peptization treatment, and then 67 g of the slurry of the magnesium-aluminum matrix material prepared in step (1) is added (the dry basis mass of the magnesium-aluminum matrix material is 10% of the total dry basis mass of the additive raw material), and the mixture is mixed and stirred evenly to form a raw material colloid; the raw material colloid is spray-dried to obtain particles with an average particle size of 90-100 μm, and the particles are cured and calcined at 350°C for 2 hours to obtain the heavy metal resistance additive.

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

[0096] The heavy metal resistance additive sample is recorded as S2. The physical and chemical properties of the samples are shown in Table 1, and the reaction properties are shown in Table 2.

[0097] Example 3

[0098] This embodiment provides an anti-heavy metal additive, and the preparation method thereof includes:

[0099] (1) Preparation of magnesium-aluminum matrix material: 161 grams of pseudo-boehmite was taken, 239 grams of deionized water was added, 15 grams of hydrochloric acid with a mass concentration of 36%-38% was added under continuous stirring, and the temperature was raised to 60°C and maintained for 1 hour for peptization treatment to obtain peptized pseudo-boehmite slurry; 50 grams of magnesium oxide was taken, 75 grams of deionized water was added, and the mixture was evenly mixed and added to the peptized pseudo-boehmite slurry, and then 4.5 grams of hexadecyltrimethylammonium chloride was added, and the mixture was beaten and stirred for 60 minutes to obtain magnesium-aluminum colloidal slurry; the magnesium-aluminum colloidal slurry was transferred to a crystallization reactor for crystallization reaction, and the reaction was carried out 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 additive: 97 g of pseudo-boehmite and 76 g of cerium nitrate are added to 133 g of deionized water, and 12 g of hydrochloric acid with a mass concentration of 36%-38% is added under continuous stirring, and the temperature is raised to 60°C and maintained for 60 minutes for peptization treatment; 60 g of magnesium oxide is added to 90 g of deionized water, and the mixture is mixed evenly, and then added to the mixed slurry containing pseudo-boehmite, cerium and vanadium after the peptization treatment, and then 167 g of the slurry of the magnesium-aluminum matrix material prepared in step (1) is added (the dry basis mass of the magnesium-aluminum matrix material is 25% of the total dry basis mass of the additive raw material), and the mixture is mixed and stirred evenly to form a raw material colloid; the raw material colloid is spray-dried to obtain particles with an average particle size of 90-100 μm, and the particles are cured and calcined at 400°C for 1 hour to obtain the heavy metal resistance additive.

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

[0102] The heavy metal resistance additive sample is recorded as S3. The physical and chemical properties of the samples are shown in Table 1, and the reaction properties are shown in Table 2.

[0103] Example 4

[0104] This embodiment provides an anti-heavy metal additive, and the preparation method thereof includes:

[0105] (1) Preparation of magnesium-aluminum matrix material: 161 grams of pseudo-boehmite was added to 239 grams of deionized water, and 15 grams of nitric acid with a mass concentration of 65%-68% was added under continuous stirring, and the temperature was raised to 60°C and maintained for 1 hour for peptization treatment to obtain peptized pseudo-boehmite slurry; 80 grams of magnesium oxide was added to 187 grams of deionized water, and the mixture was added to the peptized pseudo-boehmite slurry, and then 9 grams of hexadecyltrimethylammonium chloride was added, and the mixture was beaten and stirred for 60 minutes to obtain magnesium-aluminum colloidal slurry; the magnesium-aluminum colloidal slurry was transferred to a crystallization reactor for crystallization reaction, and the reaction was carried out 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 additive: 97 g of pseudo-boehmite, 47 g of kaolin, 136 g of yttrium nitrate, 307 g of deionized water, 12 g of hydrochloric acid with a mass concentration of 36%-38% was added under continuous stirring, and the temperature was raised to 70°C and maintained for 60 minutes for peptization treatment; 30 g of magnesium oxide was added, 45 g of deionized water was added, the mixture was mixed evenly, and the mixture was added to the mixed slurry containing pseudo-boehmite, rare earth and clay after the peptization treatment, and then 100 g of the slurry of magnesium aluminum matrix material prepared in step (1) was added (the dry basis mass of magnesium aluminum matrix material is 15% of the total dry basis mass of the additive raw material), and the mixture was mixed and stirred evenly to form a raw material colloid; the raw material colloid was spray dried to obtain particles with an average particle size of 90-100 μm, and the particles were cured and calcined at 500°C for 30 minutes to obtain the heavy metal resistance additive.

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

[0108] The heavy metal resistance additive sample is recorded as S4. The physical and chemical properties of the samples are shown in Table 1, and the reaction properties are shown in Table 2.

[0109] Example 5

[0110] This embodiment provides an anti-heavy metal additive, and the preparation method thereof includes:

[0111] (1) Preparation of magnesium-aluminum matrix material: 161 grams of pseudo-boehmite was added to 239 grams of deionized water, and 20 grams of nitric acid with a mass concentration of 65%-68% was added under continuous stirring, and the temperature was raised to 80°C and maintained for 1 hour for peptization treatment to obtain peptized pseudo-boehmite slurry; 60 grams of magnesium oxide was added to 140 grams of deionized water, and the mixture was evenly mixed and added to the peptized pseudo-boehmite slurry, and then 5 grams of hexadecyltrimethylammonium chloride was added, and the mixture was beaten and stirred for 60 minutes to obtain magnesium-aluminum colloidal slurry; the magnesium-aluminum colloidal slurry was transferred to a crystallization reactor for crystallization reaction, and the reaction was carried out 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 resistance additive: 129 g of pseudo-boehmite, 24 g of kaolin, 102 g of yttrium nitrate, 283 g of deionized water, 14 g of hydrochloric acid with a mass concentration of 36%-38% is added under continuous stirring, and the temperature is raised to 70°C and maintained for 60 minutes for peptization treatment; 40 g of magnesium oxide is added to 65 g of deionized water, mixed evenly and added to the mixed slurry containing pseudo-boehmite, rare earth and clay after the peptization treatment, and then 100 g of the slurry of magnesium aluminum matrix material prepared in step (1) is added (the dry basis mass of magnesium aluminum matrix material is 15% of the total dry basis mass of the additive raw material), mixed and stirred evenly to form a raw material colloid; the raw material colloid is spray dried to obtain particles with an average particle size of 90-100 μm, and cured and calcined at 600°C for 30 minutes to obtain the heavy metal resistance additive.

[0113] The weight percentage of each component in the heavy metal resistance additive is: 29wt% of magnesium oxide, 46wt% of aluminum oxide, 15wt% of rare earth oxide, and 10wt% of oxide formed by kaolin. The weight of the raw materials is calculated on a dry basis, and the weight proportion of magnesium-aluminum matrix material in the raw materials is 15%.

[0114] The heavy metal resistance additive sample is recorded as S5. The physical and chemical properties of the samples are shown in Table 1, and the reaction properties are shown in Table 2.

[0115] Example 6

[0116] This embodiment provides an anti-heavy metal additive, and the preparation method thereof includes:

[0117] (1) Preparation of magnesium-aluminum matrix material: 161 grams of pseudo-boehmite was taken, 339 grams of deionized water was added, 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 and maintained for 1 hour for peptization treatment to obtain peptized pseudo-boehmite slurry; 50 grams of magnesium oxide was taken, 120 grams of deionized water was added, and the mixture was evenly mixed and added to the peptized pseudo-boehmite slurry, and 6 grams of hexadecyltrimethylammonium chloride was added, and the mixture was beaten and stirred for 60 minutes to obtain magnesium-aluminum colloidal slurry; the magnesium-aluminum colloidal slurry was transferred to a crystallization reactor for crystallization reaction, and the reaction was carried out 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 additive: 97 g of pseudo-boehmite and 43 g of praseodymium chloride are added to 298 g of deionized water, and 12 g of hydrochloric acid with a mass concentration of 36%-38% is added under continuous stirring, and the temperature is raised to 60°C and maintained for 60 minutes for peptization treatment; 80 g of magnesium oxide is added to 149 g of deionized water, and the mixture is mixed evenly and added to the mixed slurry containing pseudo-boehmite and rare earth after the peptization treatment, and then 133 g of the slurry of the magnesium-aluminum matrix material prepared in step (1) is added (the dry basis mass of the magnesium-aluminum matrix material is 20% of the total dry basis mass of the additive raw material), and the mixture is mixed and stirred evenly to form a raw material colloid; the raw material colloid is spray-dried to obtain particles with an average particle size of 90-100 μm, and the particles are cured and calcined at 350°C for 120 minutes to obtain the heavy metal resistance additive.

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

[0120] The heavy metal resistance additive sample is recorded as S6. The physical and chemical properties of the sample are shown in Table 1, and the reaction performance is shown in Table 2.

[0121] Example 7

[0122] This embodiment provides an anti-heavy metal additive, and the preparation method thereof includes:

[0123] (1) Preparation of magnesium-aluminum matrix material: 161 grams of pseudo-boehmite was added to 257 grams of deionized water, and 15 grams of nitric acid with a mass concentration of 65%-68% was added under continuous stirring, and the temperature was raised to 75°C and maintained for 1 hour for peptization treatment to obtain peptized pseudo-boehmite slurry; 60 grams of magnesium oxide was added to 137 grams of deionized water, and the mixture was evenly mixed and added to the peptized pseudo-boehmite slurry, and then 6 grams of hexadecyltrimethylammonium chloride was added, and the mixture was beaten and stirred for 60 minutes to obtain magnesium-aluminum colloidal slurry; the magnesium-aluminum colloidal slurry was transferred to a crystallization reactor for crystallization reaction, and the reaction was carried out 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 additive: 113 g of pseudo-boehmite, 65 g of praseodymium chloride, 323 g of deionized water, 14 g of formic acid with a mass concentration of 88% was added under continuous stirring, and the temperature was raised to 60°C and maintained for 60 minutes for peptization treatment; 70 g of magnesium oxide was added to 130 g of deionized water, mixed evenly and added to the mixed slurry containing pseudo-boehmite and rare earth after the peptization treatment, and then 100 g of the slurry of magnesium aluminum matrix material prepared in step (1) was added (the dry basis mass of magnesium aluminum matrix material is 15% of the total dry basis mass of the additive raw material), mixed and stirred evenly to form a raw material colloid; the raw material colloid was spray dried to obtain particles with an average particle size of 90-100 μm, and cured and calcined at 400°C for 30 minutes to obtain the heavy metal resistance additive.

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

[0126] The heavy metal resistance additive sample is recorded as S7. The physical and chemical properties of the samples are shown in Table 1, and the reaction properties are shown in Table 2.

[0127] Comparative Example 1

[0128] This comparative example provides an anti-heavy metal additive, and its preparation method comprises:

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

[0130] The weight percentages of the components in the heavy metal resistance additive are as follows: 40 wt % of magnesium oxide, 45 wt % of aluminum oxide, and 15 wt % of rare earth oxide.

[0131] The heavy metal resistance additive sample is recorded as D1. The sample physical and chemical properties are shown in Table 1, and the reaction performance is shown in Table 2. Compared with the preparation method of the above embodiment, this comparative example does not add magnesium aluminum matrix material during the preparation of the heavy metal resistance additive.

[0132] Comparative Example 2

[0133] This comparative example provides an anti-heavy metal additive, and its preparation method comprises:

[0134] Preparation of heavy metal resistance additive: take 103 grams of pseudo-boehmite, 59 grams of lanthanum nitrate, 35 grams of kaolin, add 259 grams of deionized water, add 13 grams of hydrochloric acid with a mass concentration of 36%-38% under continuous stirring, heat to 55°C and keep for 60 minutes for peptization treatment; take 80 grams of magnesium oxide, add 453 grams of deionized water, mix evenly, and add to the mixed slurry containing pseudo-boehmite and rare earth after the peptization treatment, mix and stir evenly to form a raw material colloid; spray dry the raw material colloid to obtain particles with an average particle size of 90-100μm, and cure and roast at 450°C for 45 minutes to obtain the heavy metal resistance additive.

[0135] The weight percentages of the components in the heavy metal resistance additive are as follows: 40 wt % of magnesium oxide, 32 wt % of aluminum oxide, 13 wt % of rare earth oxide, and 15 wt % of oxide formed by kaolin.

[0136] The heavy metal resistance additive sample is recorded as D2. The sample physical and chemical properties are shown in Table 1, and the reaction performance is shown in Table 2. Compared with the preparation method of the above embodiment, this comparative example does not add magnesium aluminum matrix material during the preparation of the heavy metal resistance additive.

[0137] Comparative Example 3

[0138] This embodiment provides an anti-heavy metal additive, and the preparation method thereof includes:

[0139] (1) Preparation of magnesium-aluminum matrix material: 161 grams of pseudo-boehmite 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, and the temperature is raised to 50°C and maintained for 1 hour for peptization treatment to obtain peptized pseudo-boehmite slurry; 30 grams of magnesium oxide is added to 45 grams of deionized water, and the mixture is mixed evenly and added to the peptized pseudo-boehmite slurry, and then 2.6 grams of hexadecyltrimethylammonium bromide is added, and the mixture is beaten and stirred for 30 minutes to obtain magnesium-aluminum colloidal slurry for standby use. The mass ratio of magnesium oxide to aluminum oxide in the material is 0.3:1.

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

[0141] The weight percentage of each component in the heavy metal resistance additive is: 58wt% of magnesium oxide, 37wt% of aluminum oxide, and 5wt% of rare earth oxide. The weight of the raw materials is calculated on a dry basis, and the weight percentage of the magnesium aluminum colloid slurry dry basis in the raw materials is 10%.

[0142] The heavy metal resistance additive sample is recorded as D3. The sample physical and chemical properties are shown in Table 1, and the reaction performance is shown in Table 2. Compared with the preparation method of the above embodiment, in the process of preparing the heavy metal resistance additive, the present comparative example uses non-crystallized magnesium aluminum colloidal slurry instead of magnesium aluminum matrix material as the additive raw material.

[0143] Comparative Example 4

[0144] This embodiment provides an anti-heavy metal additive, and the preparation method thereof includes:

[0145] (1) Preparation of magnesium-aluminum matrix material: 161 grams of pseudo-boehmite was taken, 339 grams of deionized water was added, 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 and maintained for 1 hour for peptization treatment to obtain peptized pseudo-boehmite slurry; 50 grams of magnesium oxide was taken, 120 grams of deionized water was added, and the mixture was evenly mixed and added to the peptized pseudo-boehmite slurry, and 6 grams of hexadecyltrimethylammonium chloride was added, and the mixture was beaten and stirred for 60 minutes to obtain magnesium-aluminum colloidal slurry; the magnesium-aluminum colloidal slurry was transferred to a crystallization reactor for crystallization reaction, and the reaction was carried out at 70°C for 6 hours to obtain a magnesium-aluminum matrix material. The mass ratio of magnesium oxide to aluminum oxide in the material is 0.5:1.

[0146] (2) Preparation of heavy metal resistance additive: 97 g of pseudo-boehmite and 43 g of praseodymium chloride are added to 298 g of deionized water, and 12 g of hydrochloric acid with a mass concentration of 36%-38% is added under continuous stirring, and the temperature is raised to 60°C and maintained for 60 minutes for peptization treatment; 80 g of magnesium oxide is added to 149 g of deionized water, and the mixture is mixed evenly, and then added to the mixed slurry containing pseudo-boehmite and rare earth after the peptization treatment, and then 133 g of the slurry of the magnesium-aluminum matrix material prepared in step (1) is added (the mass of the magnesium-aluminum matrix material is 20% of the dry mass of the additive raw material), and the mixture is mixed and stirred evenly to form a raw material colloid; the raw material colloid is spray-dried to obtain particles with an average particle size of 90-100 μm, and the particles are cured and calcined at 350°C for 120 minutes to obtain the heavy metal resistance additive.

[0147] The weight percentage of each component in the heavy metal resistance additive is: 50wt% of magnesium oxide, 40wt% of aluminum oxide, and 10wt% of rare earth oxide. The weight of the raw materials is calculated on a dry basis, and the weight of the magnesium-aluminum matrix material in the additive raw materials accounts for 20%. Compared with the magnesium-aluminum matrix material preparation method of the present invention, this comparative example shortens the crystallization time in the magnesium-aluminum matrix material preparation process.

[0148] Test Example 1

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

[0150] Table 1 Colloid solid content, specific surface area and wear index of anti-heavy metal additives before spraying

[0151]

[0152] (2) The performance of the heavy metal resistance additives of each embodiment and each comparative example was evaluated as follows:

[0153] Preparation of catalytic cracking catalyst: Deionized water, kaolin, pseudo-boehmite and aluminum sol are mixed at room temperature to prepare a colloid, and then hydrochloric acid with a concentration of 36%-38% is added for peptization treatment. The peptization treatment temperature is 60°C and the treatment time is 1 hour. After that, the temperature is lowered and REUSY zeolite molecular sieve is added to prepare a slurry. The mass ratio of REUSY zeolite molecular sieve, pseudo-boehmite, aluminum sol and kaolin in the slurry is 32:15:8:45. The solid content of the slurry is 35%. The amount of hydrochloric acid added is 15wt% of the amount of pseudo-boehmite added. The slurry is sprayed into shape, and the catalyst obtained by spraying is cured and calcined at 450°C for 1 hour, and then washed with ammonium chloride solution at a temperature of 60°C, filtered, and dried to obtain a catalyst sample.

[0154] Preparation of vanadium contaminated solution: Take 18.36g of ammonium metavanadate, add 800mL of deionized water, heat to dissolve in a 90°C water bath, transfer to a 1000mL volumetric flask to make up to volume, and obtain an 8g / L vanadium solution for standby use.

[0155] Preparation of nickel-contaminated solution: Take 55.73 g of nickel nitrate, add 200 ml of deionized water, fully dissolve, transfer to a 250 mL volumetric flask and make up to volume to obtain 45 g / L nickel-contaminated solution for standby use.

[0156] Methods of catalyst contamination:

[0157] The catalyst to be contaminated was dried in an oven at 120°C for 4 hours, 100 g of the dried catalyst was taken, and 75 mL of the above-mentioned vanadium contamination solution and 6.7 mL of the nickel contamination solution were added for equal volume impregnation, allowed to stand, dried in an oven, and then calcined in a muffle furnace at 500°C for 2 h, and then 5 g of the anti-heavy metal additive sample prepared in each embodiment and comparative example was added respectively, mixed evenly, and a catalytic cracking catalyst for testing was obtained for standby use.

[0158] Performance evaluation of heavy metal resistance additives in Examples and Comparative Examples:

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

[0160] Table 2 Catalytic Cracking Catalyst ACE Evaluation Results (6000ppm V, 3000ppm Ni)

[0161]

[0162] As can be seen from Table 1 and Table 2, the present invention can increase the solid content of the colloidal system formed by the raw materials of the anti-heavy metal additive by adding the magnesium-aluminum matrix material and controlling the preparation conditions of the magnesium-aluminum matrix material during the preparation of the anti-heavy metal additive, and increase the specific surface area and anti-wear ability of the anti-heavy metal additive. The anti-heavy metal additive thus obtained has significantly improved anti-nickel and vanadium pollution performance in the catalytic cracking process, excellent coke selectivity, increased light oil yield, and can increase the yield of target products (especially the yield of target products such as liquefied gas), reduce the yield of by-products such as dry gas and coke, and has broad application prospects.

Claims

1. An anti-heavy metal additive, based on the total mass of the anti-heavy metal additive being 100%, the anti-heavy metal additive comprises: Magnesium oxide 20%-60%, aluminum oxide 30%-75%, rare earth oxide 5%-20%; Wherein, 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 is 5%-25% of the total mass of the raw materials of the anti-heavy metal additive on a dry basis; The magnesium-aluminum matrix material is obtained by mixing a second magnesium source with a second aluminum source after peptization treatment and then crystallizing the mixture. The magnesium-aluminum matrix material comprises magnesium oxide and aluminum oxide in a mass ratio of 0.2-0.8:

1.

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

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

4. The heavy metal resistance additive according to claim 1, wherein The preparation method of the magnesium-aluminum matrix material comprises: mixing a slurry of a second aluminum source with an acidic substance for peptization treatment, then mixing the peptized second aluminum source slurry with a second magnesium source slurry to obtain a magnesium-aluminum colloidal slurry, and crystallizing to obtain the magnesium-aluminum matrix material; Preferably, the mass of the second aluminum source is calculated as aluminum oxide, and the mass ratio of the acidic substance to the second aluminum source is 0.10-0.5:1; Preferably, the temperature of the peptization treatment is 40-80°C, and the time of the peptization treatment is more than 1 hour; Preferably, the crystallization temperature is 50-95° C., and the crystallization time is 10-72 h.

5. The heavy metal resistance aid according to claim 4, wherein: The raw material of the magnesium-aluminum matrix material also includes a surfactant, which is added to the uncrystallized magnesium-aluminum colloidal slurry; Preferably, the surfactant comprises cetyltrimethylammonium bromide and / or cetyltrimethylammonium chloride; Preferably, 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.

6. The heavy metal resistance aid according to claim 1, wherein: The rare earth elements contained in the rare earth oxide include lanthanide elements.

7. The heavy metal resistance additive according to any one of claims 1 to 6, wherein: Taking the dry basis weight of the raw material of the anti-heavy metal additive as 100%, the raw material of the anti-heavy metal additive further comprises 0-20% of clay; Preferably, the clay comprises one or a combination of two or more of kaolin, halloysite, montmorillonite, sepiolite, hydrotalcite and rectorite.

8. A method for preparing the heavy metal resistance additive according to any one of claims 1 to 7, comprising: S1, mixing a first aluminum source, a rare earth source and an acidic substance for peptization treatment to obtain a peptization product; 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 roasting to obtain the anti-heavy metal additive.

9. The preparation method according to claim 8, wherein: In S1, the temperature of the peptization treatment is 50-80°C, and the time of the peptization treatment is 0.5h-2h.

10. The preparation method according to claim 8, wherein: In S1, the mass of the first aluminum source is calculated as aluminum oxide, and the mass ratio of the acidic substance to the first aluminum source is 0.10-0.25:

1.

11. Use of the heavy metal resistance additive according to any one of claims 1 to 7 in a catalytic cracking process.

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