Supported catalyst, preparation method therefor and use thereof, and naphtha catalytic reforming method

Abstract

Disclosed is a supported catalyst, characterized in that: the catalyst comprises a support, a reforming active element, a halogen, and sulfur, wherein the reforming active element comprises a group VIII metal element, a group VIIB metal element, and an optional rare earth metal element. Relative to the total mass of the group VIII metal element, the proportion of single-atom group VIII metal elements in the catalyst is 20% to 40%, the proportion of diatomic group VIII metal elements is 10% to 30%, and the proportion of atomic cluster group VIII metal elements is less than 70%; and the average concentration of group VIII metal atoms in a surface layer region of the catalyst is greater than the average concentration of group VIII metal atoms in other regions of the catalyst. Further disclosed are a preparation method for the supported catalyst and a use of the supported catalyst, and a naphtha catalytic reforming method.

Description

Supported catalysts, their preparation methods and applications, and naphtha catalytic reforming methods Technical Field

[0001] This invention relates to the field of catalysts, and more specifically to a supported catalyst for naphtha catalytic reforming, its preparation method and application, and a naphtha catalytic reforming method. Background Technology

[0002] Catalytic reforming is the process of reforming C6-C6 fractions of naphtha. 12 Catalytic reforming is the process by which hydrocarbon molecules undergo structural rearrangement reactions under heating, with the aid of hydrogen and a catalyst. It is the production process for high-octane gasoline blending components, light aromatics, and hydrogen. The production of high-quality, clean gasoline requires catalytic reforming to provide high-octane blending components; the production of benzene, toluene, and xylene requires feedstocks from catalytic reforming; and secondary refining processes such as hydrorefining and upgrading require inexpensive hydrogen from catalytic reforming.

[0003] Currently, supported bifunctional reforming catalysts widely used in catalytic reforming processes include hydrogenation / dehydrogenation functions provided by the metal component and acidic isomerization functions provided by the support. Reforming catalysts are typically bimetallic (or multimetallic) catalysts with activated alumina as the support, Pt as the main metal component, and containing a second metal component such as rhenium, tin, or germanium. For bifunctional reforming catalysts, these two functions work synergistically in the catalytic reforming reaction with a certain degree of matching. If the metal hydrogenation / dehydrogenation activity is too strong, coke deposition on the catalyst surface will increase rapidly, hindering the continued reforming reaction; if the metal hydrogenation / dehydrogenation activity is too weak, the catalyst activity will decrease. If the acidic isomerization activity is too strong, the catalyst's hydrocracking activity will be strong, reducing the liquid yield of the reforming products; if the acidic isomerization activity is too weak, the catalyst's hydrocracking activity will decrease. Therefore, the balance and matching between the acidic isomerization function of the support and the hydrogenation / dehydrogenation function of the metal determines the activity, selectivity and stability of the catalyst.

[0004] The reactivity of reforming catalysts is related not only to the physicochemical properties of the alumina support (such as pore structure and acidity) but also to the metal components supported on the catalyst (such as metal content, grain size, and dispersion). Therefore, the development of reforming catalysts generally starts from two aspects: the support and the metal components. First, the development of new catalysts should focus on researching new support preparation methods and optimizing the physicochemical properties of the support. This aims to achieve physicochemical properties such as low impurity content, suitable and stable crystal phase structure, sufficiently large specific surface area and suitable pore structure, good hydrothermal stability, suitable acidity, good mass and heat transfer performance, and good mechanical strength. These properties promote the alkane dehydrogenation cyclization reaction of the catalyst, reduce ring-opening reactions, and thus improve the selectivity of the cyclization reaction relative to the cracking reaction, further enhancing the activity, selectivity, and stability of the catalyst.

[0005] Currently, there is still a need for a reforming catalyst with further improved catalytic activity and aromatic selectivity. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of low catalytic activity and low aromatic selectivity of reforming catalysts in the prior art, and to provide a catalyst for naphtha catalytic reforming, its preparation method and application, and a method for naphtha catalytic reforming, wherein the catalyst has improved catalytic activity and aromatic selectivity.

[0007] The inventors discovered through research that the above objective can be achieved during the preparation of reforming catalysts by controlling the distribution concentration, local uniformity, and dispersion of reforming active element atoms, especially Group VIII metal atoms, in different regions of the reforming catalyst.

[0008] In existing methods for preparing reforming catalysts, the process typically includes support impregnation, drying, activation, and reduction steps. In the impregnation step, a solution containing chloride is used to introduce halogens into the catalyst, followed by a reduction step of the catalyst precursor to generate active metal atoms. Optionally, gaseous halides are used to replenish the halogens in the catalyst after reduction. However, the inventors have found that this method has the following drawbacks: due to the presence of polar groups such as hydroxyl groups on the support surface and in the pores, these polar groups tend to fix the reforming active elements, especially Group VIII metal atoms, generated by reduction onto the support surface and in the support pores. Even in the subsequent halogen replenishment step, gaseous halides have almost no effect on the migration of metal atoms in the support. Therefore, it is impossible to control the distribution concentration, uniformity, and dispersion of reforming active elements, especially Group VIII metal atoms, in different distribution regions of the support.

[0009] However, the inventors surprisingly discovered through research that, during the preparation of the reforming catalyst, if halogens are introduced simultaneously in the same step by reducing the reforming active element in the catalyst precursor using a mixture of reducing gas and gaseous halide, the distribution of the reduced reforming active element, especially Group VIII metal atoms, in the support can be adjusted. This means increasing the concentration and local distribution uniformity of the reforming active element, especially Group VIII metal atoms, in the surface region of the support, and improving the dispersion of the reforming active element, especially Group VIII metal atoms. In this specification, the term "local distribution uniformity" refers to the uniformity of reforming active element atoms, especially Group VIII metal atoms, in the surface region, inner region, or core region of the catalyst, respectively. For this invention, the catalyst is divided into three regions along its radius from the core of the catalyst particle, such as the center of a sphere or the center of a strip cross-section, towards the catalyst surface: a core region, an inner region, and a surface region, with the thickness of each region occupying 1 / 3 of its radius.

[0010] Not linked to any specific theory, the inventors believe that after obtaining the activated catalyst precursor through calcination, a mixture of reducing gas and gaseous halides produced by sublimation is introduced at high temperature to simultaneously reduce and halogenate the catalyst precursor. The reducing gas reduces the reformed active element ions into free metal atoms, while the gaseous halides react with hydroxyl groups on the support surface and pore surface, chemically binding to the support surface and pores. This reduces the number of hydroxyl groups on the catalyst surface that can contact free metal ions and atoms, thereby lowering the adsorption force of the pore surface on free metal ions and atoms. Simultaneously, the gaseous halide molecules react with the free metal ions and atoms... At high temperatures, atoms undergo intense collisions. Halogen ions may impart a negative charge to the surface of metal atoms. These negatively charged metal atoms, under the influence of mutual repulsion and the aforementioned collision forces, further migrate from the pores of the support to the surface. This increases the concentration of metal ions and atoms in the catalyst surface region (including the support surface and the pores within the surface layer), and enhances the dispersion and uniformity of these metal atoms, especially Group VIII metals, in these regions. Consequently, most of the metal atoms produced by reduction exist in single-atom and diatomic forms on the support surface and in the surface layer pores, forming an "eggshell" distribution of metal atoms within the support. Unlike the almost uniform distribution of metal atoms throughout the entire support volume in existing catalysts, this "eggshell" distribution of metal atoms facilitates contact between organic matter and more catalytically active sites on the catalyst, increasing the reaction rate and reducing the reaction temperature, thereby improving the aromatic selectivity of the catalyst.

[0011] To achieve the above objectives, according to a first aspect of the present invention, the present invention provides a supported catalyst, particularly a supported catalyst for naphtha catalytic reforming, the catalyst comprising a support, a reforming active element, a halogen, and sulfur, wherein the reforming active element comprises Group VIII metals, Group VIIB metals, and optionally rare earth metals; wherein, relative to the total mass of the Group VIII metals, the catalyst comprises 20% to 40% of monoatomic Group VIII metals, 10% to 30% of diatomic Group VIII metals, and less than 70% of cluster Group VIII metals, and the average concentration of Group VIII metal atoms in the surface region of the catalyst is greater than the average concentration of Group VIII metal atoms in other regions of the catalyst.

[0012] In the specification of this invention, the term "monoatomic Group VIII metal" means that a Group VIII metal exists in monatomic form, the term "diatomic Group VIII metal" means that a Group VIII metal exists in pairs of two atoms, and the term "cluster Group VIII metal" means that a Group VIII metal exists in clusters of three or more atoms.

[0013] According to a second aspect of the present invention, the present invention provides a method for preparing a catalyst according to the first aspect described above, the method comprising the following steps:

[0014] (1) The support containing sulfate is contacted, impregnated and dried with a solution containing reforming active elements, and then calcined to obtain a catalyst precursor;

[0015] (2) Activate the catalyst precursor prepared in step (1), and then halogenate and reduce the activated catalyst precursor in the same step, so that the reforming active element in the catalyst precursor is reduced while halogen is introduced into the catalyst precursor.

[0016] According to a third aspect of the invention, the invention provides the use of a catalyst according to the first aspect above, or a catalyst prepared by the preparation method according to the second aspect above, in the catalytic reforming of naphtha.

[0017] According to a fourth aspect of the present invention, the present invention provides a catalytic reforming method for naphtha, the method comprising: contacting naphtha with hydrogen in the presence of a catalyst, wherein the catalyst is the catalyst according to the first aspect above or a catalyst prepared by the preparation method according to the second aspect above.

[0018] Through the above four technical solutions, the present invention has the following technical effects: the catalyst according to the present invention has high aromatization activity and aromatic selectivity.

[0019] The supported catalyst according to the present invention is particularly suitable for the catalytic reforming of naphtha. Attached Figure Description

[0020] Figure 1 shows a microscopic photograph of the catalyst prepared in Example 8 taken by STEM.

[0021] Figure 2 shows a microscopic photograph of the catalyst prepared in Comparative Example 3 taken by STEM.

[0022] Figure 3 shows the radial distribution of Pt concentration in the cross section of the catalyst prepared in Example 8.

[0023] Figure 4 shows the radial distribution of Pt concentration in the cross section of the catalyst prepared in Comparative Example 2. Detailed Implementation

[0024] The present application will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are for illustration and explanation only, and do not limit the scope of the invention in any way.

[0025] Any specific numerical value (including the endpoints of a range) disclosed in this specification is not limited to the exact value, but should be understood to include values ​​close to that exact value. Furthermore, for the disclosed range of values, one or more new ranges of values ​​can be obtained by arbitrarily combining the endpoint values ​​of the range, the endpoint values ​​with specific point values ​​within the range, and the specific point values ​​within the range; these new ranges of values ​​should also be considered as specifically disclosed in this specification.

[0026] In this specification, the terms “Group VIII metal element” and “Group VIII metal” have the same meaning, as do “Group VIIB metal element” and “Group VIIB metal”, and the terms “rare earth metal element” and “rare earth metal” have the same meaning.

[0027] In this specification, the term "comprising" is synonymous with "including" and "containing" and is inclusive or open-ended, without excluding other elements not specified. It should be understood that the term "comprising" covers the exclusive and closed term "composed of". The term "based on" is synonymous with "contains at least 80% by weight". Unless otherwise specified, percentages given are by weight%. Furthermore, in this specification, the expression "about" corresponds to an approximation of an exact value ±5%, and the expressions "substantially" or "essentially" correspond to an approximation of at least 95%, such as at least 96%, at least 97%, at least 98%, or at least 99%. For example, "consistently composed of compound A" or "essentially composed of compound A" means containing at least 95% by weight of compound A.

[0028] Unless otherwise stated, the terms used in this specification have the same meaning as commonly understood by those skilled in the art. If a term is defined in this specification and its definition differs from the common understanding in the art, the definition in this specification shall prevail.

[0029] In this specification, except where expressly stated, any matters or issues not mentioned herein shall be directly applicable to those known in the art without any modification. Furthermore, any implementation described herein may be freely combined with one or more other implementations described herein, and the resulting technical solutions or concepts shall be considered part of the original disclosure or original record in this specification, unless those skilled in the art consider such combination manifestly unreasonable.

[0030] According to a first aspect of the invention, the invention provides a supported catalyst, particularly a supported catalyst for naphtha catalytic reforming, the catalyst comprising a support, a reforming active element, a halogen, and sulfur, wherein the reforming active element comprises Group VIII metals, Group VIIB metals, and optionally rare earth metals; wherein, relative to the total mass of the Group VIII metals, the catalyst comprises 20% to 40% monoatomic Group VIII metals, 10% to 30% diatomic Group VIII metals, and less than 70% cluster Group VIII metals.

[0031] According to one embodiment of the first aspect described above, the present invention provides a supported catalyst comprising a support, a reforming active element, a halogen, and sulfur; wherein the reforming active element comprises Group VIII metals, Group VIIB metals, and optionally rare earth metals; wherein, relative to the total mass of the Group VIII metals, the proportion of monatomic Group VIII metals in the catalyst is 20% to 40%, for example 22%, 25%, 30%, 35%, 38%, and any value within the range of any two of the above values, and the proportion of diatomic Group VIII metals is 10% to 30%, for example 12%. 15%, 20%, 25%, 28%, and any value within the range of any two of the above values, and the proportion of Group VIII metal elements in the atomic cluster is 30% to 70%, for example 65%, 60%, 55%, 50%, 45%, 40%, 35%, and any value within the range of any two of the above values; preferably, the proportion of triatomic Group VIII metal elements relative to the total mass of Group VIII metal elements can be 5% to 25%, the proportion of tetraatomic Group VIII metal elements can be 3% to 15%, and the total proportion of Group VIII metal elements in atomic clusters with more than 10 atoms does not exceed 20%.

[0032] According to a preferred embodiment of the first aspect described above, the catalyst may have any suitable shape in the art, preferably in the form of spherical particles or cylindrical strips. Preferably, the radius of the spherical particles is greater than 0.3 mm and less than 2 mm, preferably 0.4-1.5 mm, and more preferably 0.5-1.2 mm. The length of the cylindrical strips is generally greater than 2 mm, for example 3-8 mm, preferably 4-7 mm, and the radius is generally greater than 0.4 mm, preferably 0.6-1 mm, and more preferably 0.7-0.8 mm. In the catalyst, the reforming active elements, particularly Group VIII metal atoms, have an "eggshell" distribution, meaning that the average concentration of reforming active elements, particularly Group VIII metal atoms, in the surface region of the catalyst is greater than the average concentration of reforming active elements, particularly Group VIII metal atoms, in other regions of the catalyst (i.e., the core region and the inner region). Preferably, the average concentration of Group VIII metal atoms in the surface region of the catalyst is more than 1.5 times, more than 2 times, for example more than 2.5 times, or even more than 3 times, and less than 15 times, preferably less than 10 times, for example less than 8 times, for example less than 5 times. The average concentration of reforming active element atoms is expressed in atomic mass parts.

[0033] According to a preferred embodiment of the present invention, the catalyst contains, per 100 parts by mass of the support, 0.2-10 parts by mass of the reforming active element, for example, 0.5 parts by mass, 1 part by mass, 2 parts by mass, 3 parts by mass, 4 parts by mass, 5 parts by mass, 6 parts by mass, 7 parts by mass, or 8 parts by mass of the reforming active element, and any value within the range consisting of any two of the above values.

[0034] According to a preferred embodiment of the first aspect described above, the catalyst contains, relative to 100 parts by mass of the support, 1.2-2 parts by mass of halogen (e.g., 1.4, 1.6, 1.8, or 1.9 parts by mass of halogen), and any value within the range consisting of any two of the aforementioned values. By employing a halogen content within the aforementioned preferred range, the aromatization activity and aromatic selectivity of the catalyst can be further improved. According to a preferred embodiment, the halogen is selected from at least one of chlorine, fluorine, and bromine, preferably chlorine.

[0035] According to a preferred embodiment of the first aspect described above, the catalyst contains 0.1-1 parts by mass of sulfur (elementally based) per 100 parts by mass of the support, for example, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9 parts by mass of sulfur (elementally based), and any value within the range consisting of any two of the aforementioned values. By employing a sulfur content within the aforementioned preferred range, the aromatization activity and aromatic selectivity of the catalyst can be further improved.

[0036] According to a preferred embodiment of the first aspect described above, the support is alumina, more preferably γ-alumina. The support may contain phosphorus, but preferably does not, for example, it does not contain phosphate.

[0037] According to a preferred embodiment of the first aspect above, the pore volume of the carrier is 0.3-1 mL / g, preferably 0.4-0.7 mL / g; wherein the carrier has the following pore size distribution: the pore volume with a pore size less than 6 nm accounts for 1-15% of the total pore volume, preferably 3-10%; the pore volume with a pore size of 6-10 nm accounts for 35-55% of the total pore volume, more preferably 40-50%; the pore volume with a pore size of 10-20 nm accounts for 25-45% of the total pore volume, preferably 30-45%; and the pore volume with a pore size greater than 20 nm accounts for 1-15% of the total pore volume, preferably 2-10%.

[0038] According to a preferred embodiment of the first aspect described above, the specific surface area of ​​the carrier is 180-500 m². 2 / g, preferably 180-350m 2 / g, more preferably 200-350m 2 / g.

[0039] According to a preferred embodiment of the first aspect above, the reforming active element includes Group VIII metal elements, Group VIIB metal elements and optional rare earth metal elements, and preferably the catalyst simultaneously contains Group VIII metal elements, Group VIIB metal elements and rare earth metal elements.

[0040] According to a preferred embodiment of the first aspect described above, the catalyst contains, relative to every 100 parts by mass of a carrier, 0.1-4 parts by mass of a Group VIII metal, for example, 0.2 parts by mass, 0.3 parts by mass, 0.4 parts by mass, 0.5 parts by mass, 1 part by mass, 1.5 parts by mass, 2.0 parts by mass, 2.5 parts by mass, 3.0 parts by mass, or 3.5 parts by mass, and any value within the range consisting of any two of the above values.

[0041] According to a preferred embodiment of the first aspect described above, the catalyst contains, relative to every 100 parts by mass of a Group VIIB metal, for example, 0.2 parts by mass, 0.3 parts by mass, 0.4 parts by mass, 0.5 parts by mass, 1.0 parts by mass, 1.3 parts by mass, 1.5 parts by mass, 2.0 parts by mass, or 2.5 parts by mass, and any value within the range consisting of any two of the above values.

[0042] According to a preferred embodiment of the first aspect described above, the catalyst contains 0.01-3 parts by mass of rare earth metal per 100 parts by mass of the carrier, for example, 0.1 parts by mass, 0.3 parts by mass, 0.4 parts by mass, 0.5 parts by mass, 1.0 parts by mass, 1.3 parts by mass, 1.5 parts by mass, 2.0 parts by mass, or 2.5 parts by mass, and any value within the range consisting of any two of the above values.

[0043] According to a preferred embodiment of the first aspect described above, the Group VIII metal is selected from at least one of platinum, ruthenium, rhodium, and iridium, preferably platinum.

[0044] According to a preferred embodiment of the first aspect described above, the Group VIIB metal is selected from at least one of manganese, technetium, and rhenium, preferably rhenium.

[0045] According to a preferred embodiment of the first aspect above, the rare earth metal element is selected from lanthanides and / or yttrium, preferably from at least one of cerium, samarium, europium, ytterbium and yttrium, and more preferably from ytterbium and / or yttrium.

[0046] In the supported catalyst according to the present invention, the lower the mass content of sodium in the catalyst, the better, preferably not higher than 0.05%.

[0047] According to a second aspect of the present invention, the present invention provides a method for preparing a catalyst according to the first aspect described above, the method comprising the following steps:

[0048] (1) The support containing sulfate is contacted with a solution containing reforming active elements, impregnated, dried and then calcined to obtain a catalyst precursor;

[0049] (2) The catalyst precursor prepared in step (1) is activated at high temperature. The activated catalyst precursor is simultaneously subjected to halogenation-reduction treatment in the same step so that the reforming active element in the catalyst precursor is reduced and halogen is introduced into the catalyst precursor.

[0050] The catalyst prepared by the method according to the present invention has high aromatization activity and aromatic selectivity.

[0051] According to a preferred embodiment of the second aspect described above, the sulfate-containing carrier used in step (1) has a sulfate mass content of 0.3-3%, preferably 0.5-2.5%, for example 0.8%, 1.0%, 1.5% or 2.0%.

[0052] In the preparation method according to the present invention, the conditions for contacting and impregnating in step (1) can be selected from a wide range. According to a preferred embodiment, the conditions for contacting and impregnating include: a liquid / solid volume ratio of 0.4-4, preferably 0.8-4; an impregnation temperature of 15-40°C, preferably 20-30°C; and the impregnation solution containing the reforming active element further includes hydrohalic acid, preferably hydrochloric acid, so that halogens can be introduced onto the support while the metal component is uniformly dispersed on the support. There are no particular requirements for the manner of contacting and impregnating; impregnation methods commonly used in the art can be employed, such as partial impregnation and co-impregnation methods, as well as saturated impregnation or supersaturated impregnation methods. In saturated impregnation, the liquid / solid volume ratio of the impregnating solution to the carrier is less than 1.0, preferably 0.5-0.9, and the impregnating solution is completely absorbed by the carrier. In supersaturated impregnation, the liquid / solid volume ratio of the impregnating solution to the carrier is greater than 1.0, preferably 1.1-3.0. The remaining impregnating solution after supersaturated impregnation is removed by filtration or vacuum evaporation of the solvent. Vacuum evaporation of the solvent can be performed using a rotary vacuum evaporator. Supersaturated impregnation can be carried out using a vacuum rotary impregnation method. Specifically, a water-soluble compound containing the reforming active component is prepared as an impregnating solution. The impregnating solution and the carrier are added to a rotary vacuum evaporator. The carrier is impregnated with the impregnating solution under a pressure of 0.001-0.1 MPa and under heating and rotation conditions. The liquid / solid volume ratio of the impregnating solution to the carrier is 1.1-3, and the rotational linear velocity is 0.01-2 m / s. After impregnation, drying and calcination activation are performed. The pressure for vacuum rotary impregnation is preferably 0.001-0.08 MPa. During the impregnation process, heating and rotation are performed simultaneously. The heating temperature, i.e., the impregnation temperature, is 20-90℃, preferably 50-80℃, and the rotational linear speed is 0.02-0.8 m / s, preferably 0.05-0.5 m / s. The impregnation time is 1-8 hours, preferably 2-4 hours. After vacuum rotation impregnation, the catalyst is in a dry state, at which point the support can be directly removed for drying and calcination activation.

[0053] According to a preferred embodiment of the second aspect above, in step (1), the solid after contact and impregnation is dried, wherein the drying conditions are not required, as long as it is completely dried, and then calcined at a temperature of 400-700℃; the calcination is carried out in air, the gas / agent volume ratio is 500-1000:1, and the calcination time is 4-8 hours.

[0054] According to a preferred embodiment of the second aspect above, the sulfate-containing carrier is sulfate-containing alumina, and its preparation method includes: neutralizing aluminate and aluminum ion donor under solvent conditions, aging, and filtering to obtain aluminum hydroxide powder; calcining the obtained aluminum hydroxide powder to obtain a sulfate-containing alumina carrier; optionally, the calcined alumina carrier is contacted with a sulfate-containing solution; and optionally, after contact with the sulfate-containing solution, it is subjected to steam treatment. Preferably, the solvent is an aqueous solvent, such as water or an aqueous alcohol solvent.

[0055] According to a preferred embodiment of the above-described method for preparing sulfate-containing alumina, the relative crystallinity of the obtained aluminum hydroxide powder is not less than 58%.

[0056] According to a preferred embodiment of the above-described method for preparing sulfate-containing alumina, the average grain size of the aluminum hydroxide powder is 2-4 nm.

[0057] In the method for preparing sulfate-containing alumina, as long as aluminum hydroxide powder that meets the aforementioned requirements of this invention can be obtained, there are no special requirements for the conditions of the neutralization reaction. According to a preferred embodiment, the conditions of the neutralization reaction include: a pH value of 6-12 in the neutralization reaction system; a temperature of 50-100°C; and a time of 0.5-24 hours.

[0058] According to a preferred embodiment of the above-described method for preparing sulfate-containing alumina, the neutralization reaction is carried out in two steps. The conditions for the first step include: the pH value of the reaction system is 6-10; the temperature is 50-80℃; and the time is 0.5-8 hours. The conditions for the second step include: the pH value of the reaction system is 8-12; the temperature is 70-100℃; and the time is 1-12 hours.

[0059] In the above-described method for preparing sulfate-containing alumina, as long as aluminum hydroxide powder meeting the aforementioned requirements of this invention can be obtained, no special requirements are placed on the aging conditions. According to a preferred embodiment of the above-described preparation method, the aging conditions include: a temperature of 50-180°C and an aging time of 1-120 hours.

[0060] In the above method for preparing sulfate-containing alumina, the pH value of the reaction system is adjusted by alkaline substances such as sodium hydroxide and sodium carbonate.

[0061] In the above-mentioned method for preparing sulfate-containing alumina, after aging, the aluminum hydroxide powder is washed with deionized water to reduce the content of impurities such as sulfate and sodium in the aluminum hydroxide powder.

[0062] In the above-described method for preparing sulfate-containing alumina, as long as the purpose of this invention can be achieved, the sulfate-containing solution can be a solution conventionally used in the art, such as a solution containing sulfates selected from aluminum sulfate, ammonium sulfate, ammonium sulfide, sulfurous acid, sulfuric acid, hydroxylamine sulfate, hydrazine sulfate, pyrosulfuric acid, ammonium persulfate, or aluminum ammonium sulfate.

[0063] In the above method for preparing sulfate-containing alumina, the aluminum ion donor is an aluminum ion-containing salt, preferably a sulfate, and more preferably aluminum sulfate.

[0064] In the above-described method for preparing sulfate-containing alumina, the alumina support is treated with steam to increase the pore size of the support. The steam treatment can be carried out according to conventional methods in the art, under the following conditions: using saturated steam at a temperature of 40-150°C, a treatment time of 0.5-120 hours, and the amount of steam passing through the alumina support being 0.2-20 times the weight of the support.

[0065] According to one embodiment of the second aspect described above, in the solution containing the reforming active element, the soluble compound containing a Group VIII metal is selected from at least one of chloroplatinic acid, tetraammonium dichloroplatinum, ammonium chloroplatinate, platinum trichloride, platinum tetrachloride hydrate, platinum dicarbonyl dichloride, dinitrodiaminoplatinum, and sodium tetranitroplatinate, preferably chloroplatinic acid; the soluble compound containing a Group VIIB metal is selected from at least one of perrhenic acid and ammonium perrhenate; the soluble compound containing a rare earth metal element is selected from at least one of rare earth metal element carbonates, rare earth metal element oxides, rare earth metal element nitrates, and rare earth metal element chlorides, preferably rare earth metal element nitrates and / or rare earth metal element chlorides. To more uniformly disperse the Group VIII metal on the carrier, hydrochloric acid is optionally also included in the solution containing the reforming active element.

[0066] In the preparation method of the catalyst according to the present invention, the aluminum hydroxide powder needs to be shaped before calcination. For example, the aluminum hydroxide powder can be mixed with a binder commonly used in the art, such as guar gum powder, and then extruded.

[0067] In the method for preparing the catalyst according to the present invention, the calcination temperature of the aluminum hydroxide powder after molding can vary in a wide range, for example, calcination at a temperature of 450-800°C, so that the mass content of impurities such as sodium in the support is not higher than 0.1% by element and the mass content of sulfate is not higher than 3%.

[0068] According to a preferred embodiment of the second aspect above, in the catalyst preparation method according to the present invention, preferably, the catalyst precursor is not subjected to reduction treatment and / or halogenation treatment alone before the halogenation-reduction treatment is performed; the halogenation-reduction treatment includes: the activated catalyst precursor is subjected to halogenation-reduction treatment simultaneously in the presence of hydrogen and gaseous halides without prior reduction.

[0069] In the catalyst preparation method according to the present invention, there are no requirements for the halide used in the halogenation-reduction treatment. For example, it can be selected from aluminum halides, preferably aluminum chloride, wherein the halide is a gaseous halide generated by sublimation.

[0070] In the catalyst preparation method according to the present invention, no special requirements are placed on the conditions for the halogenation-reduction treatment. According to a preferred embodiment of the present invention, the conditions for the halogenation-reduction treatment include: a temperature of 450-550°C, for example 480°C, 500°C, or 520°C; and a treatment time that can be adjusted according to the desired result, for example, more than 2 hours, preferably 3-8 hours, for example 4-6 hours.

[0071] In the catalyst preparation method according to the present invention, there are no special requirements for the hydrogen / catalyst precursor volume ratio of the halogenation-reduction treatment. According to a preferred embodiment, the hydrogen / catalyst precursor volume ratio is 400-1400:1, for example, 500:1, 600:1, 700:1, 800:1, 900:1, 1000:1, 1100:1 or 1200:1.

[0072] In the catalyst preparation method according to the present invention, there are no special requirements for the mass ratio of halide / catalyst precursor in the halogenation-reduction treatment. According to a preferred embodiment, the mass ratio of halide / catalyst precursor is 0.02-0.05.

[0073] In the catalyst preparation method of the present invention, the activation of the catalyst precursor is carried out in an oxidizing environment, such as in an oxygen-containing gas, like air. According to a preferred embodiment, the activation conditions include: a temperature of 400-700°C, a gas / catalyst volume ratio of 500-1000:1, and an activation time of 4-8 hours.

[0074] The catalyst according to the invention is particularly suitable as a catalyst in naphtha catalytic reforming, whereby pre-sulfurization is no longer required before use.

[0075] According to a third aspect of the invention, the invention provides an application of the catalyst according to the invention for catalytic reforming of naphtha.

[0076] According to a fourth aspect of the present invention, the present invention provides a method for catalytic reforming of naphtha, the method comprising: contacting naphtha with hydrogen under catalytic conditions; wherein the catalyst is a catalyst according to a first aspect of the present invention or a catalyst prepared by a method according to a second aspect of the present invention.

[0077] In the naphtha catalytic reforming method according to the present invention, there are no particular requirements regarding the type or composition of the naphtha. According to a preferred embodiment, the naphtha includes straight-run naphtha with a distillation range of 40-230°C, such as at least one of coking naphtha, catalytic cracking naphtha, hydrocracking naphtha, coal liquefaction naphtha, and ethylene cracking residue oil produced in petroleum processing.

[0078] In the naphtha catalytic reforming method according to the present invention, the pressure of the contact reaction between the naphtha and hydrogen can vary in a wide range. According to a preferred embodiment of the present invention, the conditions for the contact reaction between the naphtha and hydrogen include a pressure of 0.1-9 MPa, preferably 0.3-2.5 MPa.

[0079] In the naphtha catalytic reforming method according to the present invention, the temperature of the contact reaction between the naphtha and hydrogen can vary in a wide range. According to a preferred embodiment of the present invention, the conditions for the contact reaction between the naphtha and hydrogen include a temperature of 370-600°C, preferably 450-550°C.

[0080] In the naphtha catalytic reforming method according to the present invention, the hydrogen / hydrocarbon volume ratio of the contact reaction between the naphtha and hydrogen can vary over a wide range. According to a preferred embodiment of the present invention, the conditions for the contact reaction between the naphtha and hydrogen include a hydrogen / hydrocarbon volume ratio of 800-2000, preferably 900-1500.

[0081] In the naphtha catalytic reforming method according to the present invention, the feed mass hourly space velocity (MHSV) for the contact reaction of naphtha and hydrogen can vary over a wide range. According to a preferred embodiment of the present invention, the conditions for the contact reaction of naphtha and hydrogen include a feed MHSV of 0.1-18 h⁻¹. -1 Preferably 0.5-5h -1 .

[0082] Example

[0083] The present invention will be described in detail below through embodiments, but the present invention is not limited thereto.

[0084] In the following embodiments and comparative examples:

[0085] The contents of Group VIII and Group VIIB metals were determined using a UV-2401PC ultraviolet spectrophotometer manufactured by Shimadzu Corporation, Japan; the Na content was determined using an ICAP6300 inductively coupled plasma atomic emission spectrometer manufactured by Thermo Fisher Scientific, USA; the S content was determined using a CS-34 infrared sulfur and carbon analyzer manufactured by LECO Corporation, USA; the Cl content was determined using a 410P-58C chloride ion concentration meter manufactured by Thermo Fisher Scientific, USA; and the contents of other elements were determined using a 3271E X-ray fluorescence spectrometer manufactured by Rigaku Corporation, Japan.

[0086] Specific surface area, pore volume, and pore distribution were determined using the low-temperature N2 adsorption-desorption method on an ASAP2400 static adsorption instrument manufactured by Micromeritics. Specific surface area, pore volume, and pore distribution were calculated using the BET method and the t-plot method.

[0087] The contents and proportions of monatomic Group VIII metals, diatomic Group VIII metals, and cluster Group VIII metals were obtained by taking microscopic images of the catalyst samples using an ARM200F aberration-corrected cold field emission transmission electron microscope (spherical aberration-corrected transmission scanning electron microscope) manufactured by JEOL Corporation, and then performing statistical calculations using Origin software.

[0088] The relative crystallinity of aluminum hydroxide powder was determined by X-ray diffraction using a Rigaku D / MAX-IIIA diffractometer (Japan). The average grain size of aluminum hydroxide powder was characterized using a Hitachi S-4800 scanning electron microscope (Japan).

[0089] The radial distribution of Pt content in catalyst particles was determined by measuring Pt on the cross-section of the catalyst using a JEOL JXA8800R electron probe microanalyzer (Japan) and an ISIS300 X-ray energy dispersive spectroscopy (EDS) system (Oxford, UK). The measurement method involved cutting cylindrical catalyst particles perpendicular to their sides or spherical catalyst particles along any direction passing through the center of the sphere. Twenty equidistant points were taken from the center to the edge of the cross-section, and the Pt mass fraction at each point was analyzed.

[0090] In the following examples and comparative examples, all raw materials and reagents used were commercially available.

[0091] Unless otherwise specified, room temperature refers to 25±5℃. Unless otherwise specified in this specification, other parameters involved in the following embodiments have conventional definitions in the art and are measured using conventional methods in the art.

[0092] Examples 1-7 below illustrate the preparation of alumina supports.

[0093] Example 1

[0094] (1) Preparation of aluminum hydroxide powder

[0095] In a 3L stainless steel reactor, 500mL of sodium aluminate solution with a concentration of 210g / mL was added, followed by a certain amount of aluminum sulfate solution with a concentration of 55g / mL. The pH of the mixture was adjusted to 7.3, heated to 65℃, and reacted for 1 hour with thorough stirring. Sodium carbonate solution was added to adjust the pH of the system to 8.4, and the reaction was continued with stirring for another hour. The mixture was then heated to 90℃ for aging for 7 hours. The mixture was filtered, and the filter cake was washed with 500mL of deionized water at 90℃ for a total of 10 washes. The filter cake obtained after the last wash was dried at 120℃ for 12 hours to obtain aluminum hydroxide powder containing sulfate. XRD analysis showed that the relative crystallinity of the aluminum hydroxide powder was 58%, and SEM analysis showed that the average grain size of the aluminum hydroxide powder was 3nm.

[0096] (2) Preparation of sulfate-containing alumina support

[0097] The aluminum hydroxide powder, guar gum powder, nitric acid, acetic acid, citric acid, and water were mixed evenly and kneaded according to a mass ratio of aluminum hydroxide powder:guar gum powder:nitric acid:acetic acid:citric acid:water = 50:1:2:3:3:40. The mixture was then extruded into round strips with a length of 4 mm and a radius of 0.6 mm. The wet strips were dried at 120°C for 12 hours, calcined at 650°C for 4 hours, and then treated at 650°C for 4 hours with saturated steam at 100°C (saturated steam pressure of 0.1 MPa). The gas / solid volume ratio of the air containing water vapor to the carrier was 700 / 1, and the mass ratio of water vapor to the carrier was 0.7. This yielded γ-Al2O3 carrier ZT-1 containing sulfate, with a sulfur content of 0.18% by mass of dry alumina and a Na content of 0.01% by mass of dry alumina.

[0098] The pore structure properties of ZT-1 are shown in Table 1.

[0099] Example 2

[0100] (1) Preparation of aluminum hydroxide powder

[0101] In a 3L stainless steel reactor, 500mL of sodium aluminate solution with a concentration of 210g / mL was added, along with a certain amount of aluminum sulfate solution with a concentration of 74g / mL. The pH of the slurry was adjusted to 7.3. The mixture was heated to 65℃ and reacted for 1 hour with thorough stirring. Sodium carbonate solution was then added to adjust the pH to 8.3, and the mixture was stirred at high speed for another hour. The mixture was then heated to 90℃ for aging for 2 hours. The mixture was filtered, and the filter cake was washed with 500mL of deionized water at 90℃ for a total of 6 washes. The filter cake obtained after the final wash was dried at 120℃ for 12 hours to obtain aluminum hydroxide powder containing sulfate. XRD analysis showed that the relative crystallinity of the aluminum hydroxide powder was 58%, and SEM analysis showed that the average grain size of the aluminum hydroxide powder was 3nm.

[0102] (2) Preparation of carrier

[0103] The above aluminum hydroxide powder was used to obtain γ-Al2O3 support ZT-2 according to step (2) in Example 1, wherein the sulfur content was 0.22% by mass of dry-basis aluminum oxide and the Na content was 0.025% by mass of dry-basis aluminum oxide.

[0104] The pore structure properties of ZT-2 are shown in Table 1.

[0105] Example 3

[0106] (1) Preparation of aluminum hydroxide powder

[0107] In a 3L stainless steel reactor, 500mL of sodium aluminate solution with a concentration of 210g / mL was added, along with a certain amount of aluminum sulfate solution with a concentration of 55g / mL. The pH of the slurry was adjusted to 7.2, and the mixture was heated to 65℃ and reacted for 1 hour with thorough stirring. Sodium carbonate solution was then added to adjust the pH of the system to 8.7, and stirring continued for another hour. The mixture was then heated to 90℃ for aging for 72 hours. The mixture was filtered, and the filter cake was washed with 500mL of deionized water at 90℃ for a total of 20 washes. The filter cake obtained after the final wash was dried at 120℃ for 12 hours to obtain aluminum hydroxide powder containing sulfate. XRD analysis showed that the relative crystallinity of the aluminum hydroxide powder was 58%, and SEM analysis showed that the average grain size of the aluminum hydroxide powder was 3nm.

[0108] (2) Preparation of carrier

[0109] The above aluminum hydroxide powder was taken and γ-Al2O3 carrier ZT-3 was obtained according to the method in step (2) of Example 1, wherein the sulfur content was 0.12% by mass of dry-basis aluminum oxide and the Na content was 0.008% by mass of dry-basis aluminum oxide.

[0110] The pore structure properties of ZT-3 are shown in Table 1.

[0111] Example 4

[0112] (1) Preparation of aluminum hydroxide powder

[0113] In a 3L stainless steel reactor, 500mL of sodium aluminate solution with a concentration of 210g / mL was added, along with a certain amount of aluminum sulfate solution with a concentration of 196g / mL. The pH of the slurry was adjusted to 7.3, heated to 65℃, and reacted for 1 hour with thorough stirring. Sodium carbonate solution was then added to adjust the pH to 8.4, and the reaction was continued with stirring for another hour. The mixture was then heated to 90℃ for aging for 7 hours. The mixture was filtered, and the filter cake was washed with 500mL of deionized water at 90℃ for a total of 10 washes. The filter cake obtained after the final wash was dried at 120℃ for 12 hours to obtain aluminum hydroxide powder containing sulfate. XRD analysis showed that the relative crystallinity of the aluminum hydroxide powder was 58%, and SEM analysis showed that the average grain size of the aluminum hydroxide powder was 3nm.

[0114] (2) Preparation of carrier

[0115] The aluminum hydroxide powder, guar gum powder, nitric acid, acetic acid, citric acid, and water were mixed evenly and kneaded according to a mass ratio of 50:1:2:3:3:40. The mixture was then extruded into round strips with a length of 4 mm and a radius of 0.6 mm. The wet strips were dried at 120°C for 12 hours, calcined at 650°C for 4 hours, and then treated at 650°C for 4 hours with saturated steam at 100°C (saturated steam pressure of 0.1 MPa). The gas / solid volume ratio of the air containing steam to the carrier was 700 / 1, and the mass ratio of steam to carrier was 0.7. This yielded a sulfate-containing γ-Al₂O₃ carrier ZT-4, in which the sulfur content was 0.36% by mass of dry-basis alumina and the Na content was 0.01% by mass of dry-basis alumina.

[0116] The pore structure properties of ZT-4 are shown in Table 1.

[0117] Example 5

[0118] (1) Preparation of aluminum hydroxide powder

[0119] In a 3L stainless steel reactor, 1000mL of sodium aluminate solution with a concentration of 60g / mL was added and heated to 40℃. A mixture of CO2 and air with a CO2 concentration of 35% by volume was introduced while continuously stirring to control the final pH of the slurry to 10.5. The mixture was then heated to 90℃ for aging for 60 hours. The mixture was filtered, and the filter cake was washed with 500mL of deionized water four times. It was then washed with 500mL of 0.05% by mass ammonium nitrate solution four times. The filter cake obtained from the final wash was dried at 120℃ for 12 hours to obtain aluminum hydroxide powder.

[0120] (2) Preparation of carrier

[0121] Take the above aluminum hydroxide powder and obtain the comparative γ-Al2O3 support according to the method in step (2) of Example 1, which is denoted as DBZT-5.

[0122] The pore structure properties of DBZT-5 are shown in Table 1.

[0123] Example 6

[0124] High-purity aluminum hydroxide powder was synthesized via the following alkoxyaluminum hydrolysis method: Aluminum shavings and n-pentanol were added to a three-necked flask equipped with a reflux condenser and heated to 135°C to prepare n-pentoxyaluminum, with a molar ratio of aluminum to n-pentanol of 3.3. The n-pentoxyaluminum was then hydrolyzed in deionized water at 90°C to obtain a two-phase system of n-pentanol and aluminum hydroxide slurry. The n-pentanol was separated, and the aluminum hydroxide slurry was dried at 120°C for 12 hours, followed by grinding to obtain high-purity aluminum hydroxide powder.

[0125] The high-purity aluminum hydroxide powder, guar gum powder, nitric acid, acetic acid, citric acid, and water were mixed evenly and kneaded according to a mass ratio of 50:1:2:3:3:40. The mixture was then extruded into round strips with a length of 4 mm and a radius of 0.6 mm. The wet round strips were dried at 120°C for 12 hours and calcined at 650°C for 4 hours to obtain the comparative γ-Al2O3 support, denoted as DBZT-6.

[0126] The pore structure properties of DBZT-6 are shown in Table 1.

[0127] Example 7

[0128] This embodiment is implemented according to the method of Example 3, except that the number of washing times in step (1) is 50 times, and the washing is carried out until the sulfate content is 0. Then, the γ-Al2O3 carrier containing sulfate is immersed in sulfuric acid solution so that the sulfur content in the γ-Al2O3 carrier containing sulfate prepared in step (2) is 0.12% of the dry basis alumina, and the γ-Al2O3 carrier containing sulfate ZT-7 is obtained.

[0129] The pore structure properties of ZT-7 are shown in Table 1.

[0130] Examples 8-19 and Comparative Examples 1-3 below are used to illustrate the preparation of supported catalysts.

[0131] Example 8

[0132] The carrier prepared in Example 1 was used to prepare an impregnation solution by mixing chloroplatinic acid, ammonium perrhenate, yttrium nitrate, and hydrochloric acid. The amounts of chloroplatinic acid, ammonium perrhenate, yttrium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Pt, 0.46% Re, 0.40% Y, and 1.8% Cl (relative to the mass of the carrier). The liquid / solid volume ratio was 1.5. The carrier and the impregnation solution were poured into a 500 mL flask and impregnated for 3 hours using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a temperature of 30°C, a pressure of 0.008 MPa, and a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C and dried at 120°C for 12 hours. The obtained dry solid was calcined and activated in dry air at 500℃ for 4 hours at a gas / catalyst volume ratio of 700 to obtain a catalyst precursor. Then, the catalyst precursor was simultaneously chlorinated and reduced with sublimed AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500, where the mass ratio of AlCl3 to the catalyst precursor was 0.04. The chlorination and reduction were carried out at 480℃ for 6 hours to obtain catalyst Cat-8, the composition of which is shown in Table 2. The catalyst was characterized by STEM, and the STEM micrograph is shown in Figure 1. The STEM micrograph shows that catalyst Cat-8 contains a relatively large amount of single-atom Pt and diatomic Pt, and a relatively small amount of Pt atom clusters. The specific contents of single-atom Pt, diatomic Pt, and Pt atom clusters are shown in Table 3. The results indicate that the reforming active metal Pt atoms in the catalyst are highly dispersed. The radial distribution of Pt concentration in the catalyst was measured, and the results are shown in Figure 3. This indicates that Pt has an "eggshell" distribution in the catalyst: the average concentration of Pt atoms in the surface region of the catalyst particles is about 3.0 times the average concentration of Pt atoms in the core and inner regions of the catalyst particles.

[0133] Example 9

[0134] The carrier prepared in Example 2 was used to prepare an impregnation solution by mixing ammonium ruthenium chloride, ammonium perrhenate, yttrium nitrate, and hydrochloric acid. The amounts of ammonium ruthenium chloride, ammonium perrhenate, yttrium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Ru, 0.45% Re, 0.39% Y, and 1.8% Cl (relative to the mass of the carrier). The liquid / solid volume ratio was 1.5. The carrier and the impregnation solution were poured into a 500 mL flask and impregnated for 3 hours using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a temperature of 30°C, a pressure of 0.008 MPa, and a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C and dried at 120°C for 12 hours. The obtained dry solid was calcined and activated in dry air at 500℃ for 4 hours at a gas / catalyst volume ratio of 700 to obtain a catalyst precursor. Then, the catalyst precursor was simultaneously chlorinated and reduced with sublimed AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500, where the mass ratio of AlCl3 to the catalyst precursor was 0.04. The chlorination and reduction were carried out at 480℃ for 6 hours to obtain catalyst Cat-9, the composition of which is shown in Table 2. The catalyst was characterized by STEM. The STEM micrographs show that catalyst Cat-9 contains a relatively large amount of single-atom Ru and diatomic Ru, and a relatively small amount of Ru atom clusters. The specific contents of single-atom Ru, diatomic Ru, and Ru atom clusters are shown in Table 3, indicating that the reforming active metal Ru atoms in the catalyst are highly dispersed. The radial distribution of Ru concentration in the catalyst was measured, and the results showed that Ru had an "eggshell" distribution in the catalyst: the average concentration of Ru atoms in the surface region of the catalyst particles was about 2.0 times that in the core and inner regions of the catalyst particles.

[0135] Example 10

[0136] The carrier prepared in Example 3 was used to prepare an impregnation solution by mixing chloroiridic acid, ammonium perrhenate, yttrium nitrate, and hydrochloric acid. The amounts of chloroiridic acid, ammonium perrhenate, yttrium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Ir, 0.45% Re, 0.39% Y, and 1.8% Cl (relative to the mass of the carrier). The liquid / solid volume ratio was 1.5. The carrier and the impregnation solution were poured into a 500 mL flask and impregnated for 3 hours using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a temperature of 30°C, a pressure of 0.008 MPa, and a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C and dried at 120°C for 12 hours. The obtained dry solid was calcined and activated in dry air at 500℃ for 4 hours at a gas / catalyst volume ratio of 700 to obtain a catalyst precursor. Then, the catalyst precursor was simultaneously chlorinated and reduced with sublimed AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500, where the mass ratio of AlCl3 to the catalyst precursor was 0.04. The chlorination and reduction were carried out at 480℃ for 6 hours to obtain catalyst Cat-10, the composition of which is shown in Table 2. The catalyst was characterized by STEM. STEM micrographs show that catalyst Cat-10 contains a relatively large amount of single-atom or diatomic Ir and a small amount of Ir atom clusters. The specific contents of single-atom Ir, diatomic Ir, and Ir atom clusters are shown in Table 3, indicating that the reforming active metal Ir atoms in the catalyst are highly dispersed. The radial distribution of Ir concentration in the catalyst was measured, and the results showed that Ir had an "eggshell" distribution in the catalyst: the average concentration of Ir atoms in the surface region of the catalyst particles was about 2.8 times that in the core and inner regions of the catalyst particles.

[0137] Example 11

[0138] The carrier prepared in Example 4 was used to prepare an impregnation solution by mixing ammonium rhodium chlororhodium, ammonium perrhenate, yttrium nitrate, and hydrochloric acid. The amounts of ammonium rhodium chlororhodium, ammonium perrhenate, yttrium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Rh, 0.45% Re, 0.40% Y, and 1.8% Cl (relative to the mass of the carrier). The liquid / solid volume ratio was 1.5. The carrier and the impregnation solution were poured into a 500 mL flask and impregnated for 3 hours using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a temperature of 30°C, a pressure of 0.008 MPa, and a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C and dried at 120°C for 12 hours. The obtained dry solid was calcined and activated in dry air at 500℃ for 4 hours at a gas / catalyst volume ratio of 700 to obtain a catalyst precursor. Then, the catalyst precursor was simultaneously chlorinated and reduced with sublimed AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500, where the mass ratio of AlCl3 to the catalyst precursor was 0.04. The chlorination and reduction were carried out at 480℃ for 6 hours to obtain catalyst Cat-11, the composition of which is shown in Table 2. The catalyst was characterized by STEM. The STEM micrographs show that catalyst Cat-11 contains a relatively large amount of single-atom or diatomic Rh and a small amount of Rh atom clusters. The specific contents of single-atom Rh, diatomic Rh, and Rh atom clusters are shown in Table 3, indicating that the reforming active metal Rh atoms in the catalyst are highly dispersed. The radial distribution of Rh concentration in the catalyst was measured, and the results showed that Rh had an "eggshell" distribution in the catalyst: the average concentration of Rh atoms in the surface region of the catalyst particles was about 2.2 times that in the core and inner regions of the catalyst particles.

[0139] Example 12

[0140] The carrier prepared in Example 1 was used to prepare an impregnation solution by mixing chloroplatinic acid, ammonium perrhenate, ytterbium nitrate, and hydrochloric acid. The amounts of chloroplatinic acid, ammonium perrhenate, ytterbium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Pt, 0.46% Re, 0.40% Yb, and 1.8% Cl (relative to the mass of the carrier). The liquid / solid volume ratio was 1.5. The carrier and impregnation solution were poured into a 500 mL flask and impregnated for 3 hours using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a temperature of 30°C and a pressure of 0.008 MPa, with a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C and then dried at 120°C for 12 hours. The obtained dry solid was calcined and activated in dry air at 500℃ for 4 hours at a gas / catalyst volume ratio of 700 to obtain a catalyst precursor. Then, the catalyst precursor was simultaneously chlorinated and reduced with sublimed AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500, where the mass ratio of AlCl3 to the catalyst precursor was 0.04. The chlorination and reduction were carried out at 480℃ for 6 hours to obtain catalyst Cat-12, the composition of which is shown in Table 2. The catalyst was characterized by STEM. The STEM micrographs show that catalyst Cat-12 contains a relatively large amount of single-atom Pt and diatomic Pt, and a relatively small amount of Pt atom clusters. The specific contents of single-atom Pt, diatomic Pt, and Pt atom clusters are shown in Table 3. The results indicate that the reforming active metal Pt atoms in the catalyst are highly dispersed. The radial distribution of Pt concentration in the catalyst was measured, and the results showed that Pt has an "eggshell" distribution in the catalyst. The average concentration of Pt atoms in the surface region of the catalyst particles is about 2.7 times that in the core region and inner region of the catalyst particles.

[0141] Example 13

[0142] The carrier prepared in Example 5 was first impregnated with sulfuric acid solution to obtain a sulfate-containing carrier, wherein the sulfur content was 0.10% by mass of dry alumina. Then, chloroplatinic acid, ammonium perrhenate, europium nitrate, and hydrochloric acid were prepared as an impregnation solution, wherein the amounts of chloroplatinic acid, ammonium perrhenate, europium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Pt, 0.46% Re, 0.40% Eu, and 1.8% Cl (relative to the carrier mass), with a liquid / solid volume ratio of 1.5. The sulfate-containing carrier and the impregnation solution were then poured into a 500 mL flask, and the carrier was impregnated for 3 hours at 30°C and 0.008 MPa pressure using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C, and finally dried at 120°C for 12 hours. The obtained dry solid was calcined and activated in dry air at 500℃ and a gas / catalyst volume ratio of 700 for 4 hours to obtain a catalyst precursor. Then, the catalyst precursor was simultaneously chlorinated and reduced with sublimed AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500. The mass ratio of AlCl3 to the catalyst precursor was 0.04. The chlorination and reduction were carried out at 480℃ for 6 hours to obtain catalyst Cat-13, the composition of which is shown in Table 2. The catalyst was characterized by STEM. The STEM micrographs show that catalyst Cat-13 contains a small amount of single-atom Pt and diatomic Pt, and a relatively large amount of Pt atom clusters. The specific contents of single-atom Pt, diatomic Pt, and Pt atom clusters are shown in Table 3. The results indicate that the reforming active metal Pt atoms in the catalyst are highly dispersed. The radial distribution of Pt concentration in the catalyst was measured, and the results showed that the reforming active metal Pt had an "eggshell" distribution in the catalyst: the average concentration of Pt atoms in the surface region of the catalyst particles was about 1.8 times that in the core and inner regions of the catalyst particles.

[0143] Example 14

[0144] The carrier prepared in Example 5 was first impregnated with sulfuric acid solution to obtain a sulfate-containing carrier, wherein the sulfur content was 0.11% by mass of dry alumina. Then, chloroplatinic acid, ammonium pertechnetate, yttrium nitrate, and hydrochloric acid were prepared as an impregnation solution, wherein the amounts of chloroplatinic acid, ammonium pertechnetate, yttrium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Pt, 0.45% Tc, 0.40% Y, and 1.8% Cl (relative to the carrier mass), with a liquid / solid volume ratio of 1.5. The sulfate-containing carrier and the impregnation solution were then poured into a 500 mL flask, and the carrier was impregnated for 3 hours at 30°C and 0.008 MPa pressure using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C, and finally dried at 120°C for 12 hours. The obtained dry solid was calcined and activated in dry air at 500℃ and a gas / catalyst volume ratio of 700 for 4 hours to obtain a catalyst precursor. Then, the catalyst precursor was simultaneously chlorinated and reduced with sublimed AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500. The mass ratio of AlCl3 to the catalyst precursor was 0.04. The chlorination and reduction were carried out at 480℃ for 6 hours to obtain catalyst Cat-14, the composition of which is shown in Table 2. The catalyst was characterized by STEM. The STEM micrographs show that catalyst Cat-14 contains a small amount of single-atom Pt and diatomic Pt, and a relatively large amount of Pt atom clusters. The specific contents of single-atom Pt, diatomic Pt, and Pt atom clusters are shown in Table 3. The results indicate that the reforming active metal Pt atoms in the catalyst are highly dispersed. The radial distribution of Pt concentration in the catalyst was measured, and the results showed that the reforming active metal Pt had an "eggshell" distribution in the catalyst: the average concentration of Pt atoms in the surface region of the catalyst particles was about 1.9 times that in the core and inner regions of the catalyst particles.

[0145] Example 15

[0146] The carrier prepared in Example 1 was used to prepare an impregnation solution by mixing chloroplatinic acid, ammonium permanganate, yttrium nitrate, and hydrochloric acid. The amounts of chloroplatinic acid, ammonium permanganate, yttrium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Pt, 0.46% Mn, 0.40% Y, and 1.8% Cl (relative to the mass of the carrier). The liquid / solid volume ratio was 1.5. The carrier and the impregnation solution were poured into a 500 mL flask and impregnated for 3 hours using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a temperature of 30°C and a pressure of 0.008 MPa, with a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C and then dried at 120°C for 12 hours. The obtained dry solid was calcined and activated in dry air at 500℃ and a gas / catalyst volume ratio of 700 for 4 hours to obtain a catalyst precursor. Then, the catalyst precursor was simultaneously chlorinated and reduced with sublimed AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500, where the mass ratio of AlCl3 to the catalyst precursor was 0.04. The chlorination and reduction were carried out at 480℃ for 6 hours to obtain catalyst Cat-15, the composition of which is shown in Table 2. The catalyst was characterized by STEM. The STEM micrographs show that catalyst Cat-15 contains a relatively large amount of single-atom Pt and diatomic Pt, and a relatively small amount of Pt atom clusters. The specific contents of single-atom Pt, diatomic Pt, and Pt atom clusters are shown in Table 3. The results indicate that the reforming active metal Pt atoms in this catalyst are highly dispersed. The radial distribution of Pt concentration in the catalyst was measured, and the results showed that the reforming active metal Pt atoms had an "eggshell" distribution in the catalyst. The average concentration of Pt atoms in the surface region of the catalyst particles was about 2.1 times that in the core region and inner region of the catalyst particles.

[0147] Example 16

[0148] The carrier prepared in Example 1 was used to prepare an impregnation solution by mixing chloroplatinic acid, ammonium perrhenate, cerium nitrate, and hydrochloric acid. The amounts of chloroplatinic acid, ammonium perrhenate, cerium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Pt, 0.46% Re, 0.39% Ce, and 1.8% Cl (relative to the mass of the carrier). The liquid / solid volume ratio was 1.5. The carrier and the impregnation solution were poured into a 500 mL flask and impregnated for 3 hours using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a temperature of 30°C and a pressure of 0.008 MPa, with a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C and then dried at 120°C for 12 hours. The obtained dry solid was calcined and activated in dry air at 500℃ and a gas / catalyst volume ratio of 700 for 4 hours to obtain a catalyst precursor. Then, the catalyst precursor was simultaneously chlorinated and reduced with sublimed AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500, where the mass ratio of AlCl3 to the catalyst precursor was 0.04. The chlorination and reduction were carried out at 480℃ for 6 hours to obtain catalyst Cat-16, the composition of which is shown in Table 2. The catalyst was characterized by STEM. STEM micrographs show that catalyst Cat-16 contains a relatively large amount of single-atom Pt and diatomic Pt, and a relatively small amount of Pt atom clusters. The specific contents of single-atom Pt, diatomic Pt, and Pt atom clusters are shown in Table 3. The results indicate that the reforming active metal Pt atoms in the catalyst are highly dispersed. The radial distribution of Pt content in the catalyst was measured, showing that the average concentration of Pt atoms in the surface region of the catalyst particles was about 2.2 times that in the core and inner regions of the catalyst particles.

[0149] Example 17

[0150] The carrier prepared in Example 1 was used to prepare an impregnation solution by mixing chloroplatinic acid, ammonium perrhenate, yttrium nitrate, and hydrochloric acid. The amounts of chloroplatinic acid, ammonium perrhenate, yttrium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 1.2% Pt, 1.41% Re, 1.50% Y, and 2.45% Cl (relative to the mass of the carrier). The liquid / solid volume ratio was 1.5. The carrier and the impregnation solution were poured into a 500 mL flask and impregnated for 3 hours using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a temperature of 30°C, a pressure of 0.008 MPa, and a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C and dried at 120°C for 12 hours. The obtained dry solid was calcined and activated in dry air at 500℃ for 4 hours at a gas / catalyst volume ratio of 700 to obtain a catalyst precursor. Then, the catalyst precursor was simultaneously chlorinated and reduced with sublimed AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500, where the mass ratio of AlCl3 to the catalyst precursor was 0.04. The chlorination and reduction were carried out at 480℃ for 6 hours to obtain catalyst Cat-17, the composition of which is shown in Table 2. The catalyst was characterized by STEM. STEM micrographs show that catalyst Cat-17 contains a relatively large amount of single-atom Pt and diatomic Pt, and a relatively small amount of Pt atom clusters. The specific contents of single-atom Pt, diatomic Pt, and Pt atom clusters are shown in Table 3. The results indicate that the reforming active metal Pt atoms in the catalyst are highly dispersed. The radial distribution of Pt content in the catalyst was measured, and the results showed that the average concentration of Pt atoms in the surface region of the catalyst particles was about 2.5 times that in the core and inner regions of the catalyst particles.

[0151] Example 18

[0152] The carrier prepared in Example 7 was used to prepare an impregnation solution by mixing chloroplatinic acid, ammonium pertechnetate, cerium nitrate, and hydrochloric acid. The amounts of chloroplatinic acid, ammonium pertechnetate, cerium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Pt, 0.46% Tc, 0.39% Ce, and 1.5% Cl (relative to the mass of the carrier). The liquid / solid volume ratio was 1.5. The carrier and the impregnation solution were poured into a 500 mL flask and impregnated for 3 hours using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a temperature of 30°C and a pressure of 0.008 MPa, with a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C and then dried at 120°C for 12 hours. The obtained dry solid was calcined and activated in dry air at 500℃ and a gas / catalyst volume ratio of 700 for 4 hours to obtain a catalyst precursor. Then, the catalyst precursor was simultaneously chlorinated and reduced with sublimed AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500, where the mass ratio of AlCl3 to the catalyst precursor was 0.04. The chlorination and reduction were carried out at 480℃ for 6 hours to obtain catalyst Cat-18, the composition of which is shown in Table 2. The catalyst was characterized by STEM. STEM micrographs showed that catalyst Cat-18 contained a relatively large amount of single-atom Pt and diatomic Pt, and a relatively small amount of Pt atom clusters. The specific contents of single-atom Pt, diatomic Pt, and Pt atom clusters are shown in Table 3. The results indicate that the reforming active metal Pt atoms in the catalyst are highly dispersed. The radial distribution of Pt content in the catalyst was measured, and the results showed that the average concentration of Pt atoms in the surface region of the catalyst particles was about 1.9 times that in the core and inner regions of the catalyst particles.

[0153] Example 19

[0154] The carrier prepared in Example 6 was first impregnated with sulfuric acid solution to obtain a sulfate-containing carrier, wherein the sulfur content was 0.11% by mass of dry alumina. Then, chloroplatinic acid, ammonium pertechnetate, yttrium nitrate, and hydrochloric acid were prepared as an impregnation solution, wherein the amounts of chloroplatinic acid, ammonium pertechnetate, yttrium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Pt, 0.45% Tc, 0.40% Y, and 1.5% Cl (relative to the carrier mass), with a liquid / solid volume ratio of 1.5. The sulfate-containing carrier and the impregnation solution were then poured into a 500 mL flask, and the carrier was impregnated for 3 hours at 30°C and 0.008 MPa pressure using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C, and finally dried at 120°C for 12 hours. The obtained dry solid was calcined and activated in dry air at 500℃ and a gas / catalyst volume ratio of 700 for 4 hours to obtain a catalyst precursor. Then, the catalyst precursor was simultaneously chlorinated and reduced with sublimed AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500. The mass ratio of AlCl3 to the catalyst precursor was 0.04. The chlorination and reduction were carried out at 480℃ for 6 hours to obtain catalyst Cat-19, the composition of which is shown in Table 2. The catalyst was characterized by STEM. STEM micrographs showed that catalyst Cat-19 contained a small amount of single-atom Pt and diatomic Pt, and a relatively large amount of Pt atom clusters. The specific contents of single-atom Pt, diatomic Pt, and Pt atom clusters are shown in Table 3. The results indicate that the reforming active metal Pt atoms in the catalyst are highly dispersed. The radial distribution of Pt content in the catalyst was measured, and the results showed that the average concentration of Pt atoms in the surface region of the catalyst particles was about 1.7 times that in the core and inner regions of the catalyst particles.

[0155] Comparative Example 1

[0156] The carrier prepared in Example 1 was used to prepare an impregnation solution by mixing chloroplatinic acid, ammonium perrhenate, yttrium nitrate, and hydrochloric acid. The amounts of chloroplatinic acid, ammonium perrhenate, yttrium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Pt, 0.46% Re, 0.40% Y, and 1.45% Cl (relative to the mass of the carrier). The liquid / solid volume ratio was 1.5. The carrier and the impregnation solution were poured into a 500 mL flask and impregnated for 3 hours at 30°C and 0.008 MPa pressure using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory). The solid was then dried under vacuum at 70°C and dried at 120°C for 12 hours. The catalyst precursor was activated by calcination in dry air at 500℃ and a gas / catalyst volume ratio of 700 for 4 hours. Then, the catalyst was reduced with hydrogen at 480℃ and a gas / catalyst volume ratio of 500 for 6 hours. After reduction, the catalyst was cooled to 425℃, and 0.10% (relative to catalyst mass) of hydrogen sulfide was added to the hydrogen stream for pre-sulfurization, yielding the control catalyst DBCat-1, whose composition is shown in Table 2. This catalyst was characterized by STEM. STEM micrographs showed that catalyst DBCat-1 contained only small amounts of single-atom and diatomic Pt and a large number of Pt atom clusters, indicating a low dispersion of the reforming active metal Pt atoms in this catalyst. The radial distribution of Pt content in the catalyst was measured, and the results showed that the average concentration of Pt atoms in the surface region of the catalyst particles was approximately 1.1 times that in the core and inner regions of the catalyst particles.

[0157] Comparative Example 2

[0158] The carrier prepared in Example 1 was used to prepare an impregnation solution by mixing chloroplatinic acid, ammonium perrhenate, yttrium nitrate, and hydrochloric acid. The amounts of chloroplatinic acid, ammonium perrhenate, yttrium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Pt, 0.46% Re, 0.40% Y, and 1.5% Cl (relative to the mass of the carrier). The liquid / solid volume ratio was 1.5. The carrier and the impregnation solution were poured into a 500 mL flask and impregnated for 3 hours using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a temperature of 30°C and a pressure of 0.008 MPa, with a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C and dried at 120°C for 12 hours. The catalyst precursor was activated by calcination in dry air at 500℃ and a gas / catalyst volume ratio of 700 for 4 hours to obtain the catalyst precursor. Then, the catalyst precursor was reduced with hydrogen at 480℃ and a gas / catalyst volume ratio of 500 for 6 hours to obtain the control catalyst DBCat-2, the composition of which is shown in Table 2. This catalyst was characterized by STEM. STEM micrographs show that catalyst DBCat-2 contains a large number of Pt atom clusters and only a small amount of single-atom and diatomic Pt, indicating a low dispersion of the reforming active metal Pt atoms in this catalyst. The radial distribution of Pt content in this catalyst was measured, and the results are shown in Figure 4. The results show that the average concentration of Pt atoms in the surface region of the catalyst particles is approximately 1.1 times the average concentration of Pt atoms in the core and inner regions of the catalyst particles.

[0159] Comparative Example 3

[0160] The carrier prepared in Example 1 was used to prepare an impregnation solution by mixing chloroplatinic acid, ammonium perrhenate, yttrium nitrate, and hydrochloric acid. The amounts of chloroplatinic acid, ammonium perrhenate, yttrium nitrate, and hydrochloric acid were such that the prepared impregnation solution contained 0.22% Pt, 0.46% Re, 0.40% Y, and 1.5% Cl (relative to the mass of the carrier). The liquid / solid volume ratio was 1.5. The carrier and the impregnation solution were poured into a 500 mL flask and impregnated for 3 hours using a rotary vacuum evaporator (manufactured by Shanghai Yarong Biochemical Instrument Factory) at a temperature of 30°C and a pressure of 0.008 MPa, with a rotational speed of 0.03 m / s. The solid was then dried under vacuum at 70°C and dried at 120°C for 12 hours. The catalyst precursor was activated by calcination in dry air at 500℃ and a gas / catalyst volume ratio of 700 for 4 hours. Then, the catalyst precursor was reduced with hydrogen at 480℃ and a gas / catalyst volume ratio of 500 for 6 hours. Following this reduction, the precursor was chlorinated with sublimated AlCl3 carried by hydrogen at 480℃ and a gas / catalyst volume ratio of 500 to obtain the control catalyst DBCat-3, the composition of which is shown in Table 2. This catalyst was characterized by STEM, and the STEM micrograph is shown in Figure 2. The STEM micrograph shows that catalyst DBCat-3 contains a large number of Pt atom clusters and only a small amount of single-atom and diatomic Pt (the contents of which are shown in Table 3), indicating a low dispersion of the reforming active metal Pt atoms in this catalyst. The radial distribution of Pt content in the catalyst was measured, and the results showed that the average concentration of Pt atoms in the surface region of the catalyst particles was about 1.2 times that in the core and inner regions of the catalyst particles.

[0161] Test Example 1

[0162] The catalytic performance of catalysts Cat-8 to Cat-19 prepared in Examples 8-19 and comparative catalysts DBCat-1 to DBCat-3 prepared in Comparative Examples 1-3 was evaluated using refined naphtha as feedstock in a 100 mL microreactor. The refined naphtha was obtained from the continuous reforming unit of Sinopec Yanshan Petrochemical Company, and its properties are shown in Table 4.

[0163] The evaluation conditions included: a reaction temperature of 500℃, a pressure of 1.50 MPa, and a naphtha feed mass hourly space velocity of 1.85 h⁻¹. -1 The hydrogen / hydrocarbon volume ratio was 1200:1, and the reaction time was 120 hours. Samples were taken every 24 hours, and the C5 was calculated. + Calculate the average values ​​for liquid yield and aromatic yield. Among them, C5... +Liquid yield = (Weight of reaction product liquid / Weight of feed) × 100%. Aromatic yield = Aromatic content × Liquid yield × 100%. The performance evaluation results of the reforming catalyst are shown in Table 5.

[0164] Table 1. Properties of the carrier

[0165] Table 2. Composition of the catalyst

[0166] Table 3. Content of reforming active elements in catalysts

[0167] As shown in Table 3, the catalyst according to the present invention exhibits a significantly higher concentration of Group VIII element atoms in the surface region and a significantly higher dispersion of Group VIII element atomic centers compared to the comparative catalyst. This means that more monoatomic and diatomic Group VIII elements are present in the surface region of the catalyst, making it easier for organic compounds to contact the monoatomic and diatomic Group VIII elements, which serve as catalytic active centers, resulting in higher catalytic activity. In the reforming reaction, compared to the comparative catalyst, naphtha can undergo reforming in a shorter time and at a lower temperature, thus significantly improving its reforming efficiency and aromatic selectivity.

[0168] Table 4. Properties of raw naphtha

[0169] Table 5. Catalyst Performance

[0170] As can be seen from the data in Table 5, the catalyst of the present invention has significantly better catalytic performance than the comparative catalyst, producing higher C5 content. + Liquid yield and aromatics yield. Furthermore, it can be seen that the preparation method of the catalyst support has a significant impact on the properties of the final catalyst.

[0171] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

[0172] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0173] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A supported catalyst, characterized in that, The catalyst comprises a support, a reforming active element, halogens, and sulfur, wherein the reforming active element includes Group VIII metals, Group VIIB metals, and optional rare earth metals. In the catalyst, relative to the total mass of Group VIII metals, the proportion of monatomic Group VIII metals is 20% to 40%, the proportion of diatomic Group VIII metals is 10% to 30%, and the proportion of cluster Group VIII metals is less than 70%, and the average concentration of Group VIII metal atoms in the surface region of the catalyst is greater than the average concentration of Group VIII metal atoms in other regions of the catalyst.

2. The catalyst according to claim 1, characterized in that... The catalyst, relative to every 100 parts by weight of the support, contains: 1.2-2 parts by mass of halogens, and / or 0.1-1 parts by mass of sulfur (elemental), and / or 0.2-10 parts by mass of reforming active elements, calculated as elements.

3. The catalyst according to any one of claims 1-2, characterized in that... The support is alumina, wherein the pore volume of the support is 0.3-1 mL / g, preferably 0.4-0.7 mL / g, and / or the specific surface area of ​​the support is 180-500 m². 2 / g, preferably 180-350m 2 / g; Preferably, the carrier has the following pore size distribution: pores with a pore size less than 6 nm account for 1-15% of the total pore volume, preferably 3-10%; pores with a pore size of 6-10 nm account for 35-55% of the total pore volume, preferably 40-50%; pores with a pore size of 10-20 nm account for 25-45% of the total pore volume, preferably 30-45%; and pores with a pore size greater than 20 nm account for 1-15% of the total pore volume, preferably 2-10%.

4. The catalyst according to any one of claims 1-2, characterized in that... The average concentration of Group VIII metal atoms in the surface region of the catalyst is more than 1.5 times, preferably more than 2 times, for example more than 2.5 times, or even more than 3 times, and less than 15 times, preferably less than 10 times, for example less than 8 times, for example less than 5 times.

5. The catalyst according to any one of claims 1-2, characterized in that... The catalyst contains, in elemental terms, the following components relative to 100 parts by mass of the support: 0.1-4 parts by mass of Group VIII metals, 0.1-3 parts by mass of Group VIIB metals, and 0.01-3 parts by mass of rare earth metals.

6. The catalyst according to any one of claims 1-2, characterized in that... The halogen is selected from at least one of chlorine, fluorine and bromine, preferably chlorine, and / or the Group VIII metal is selected from at least one of platinum, ruthenium, rhodium and iridium, preferably platinum, and / or the Group VIIB metal is selected from at least one of manganese, technetium and rhenium, preferably rhenium, and / or the rare earth metal element is selected from at least one of cerium, samarium, europium, ytterbium and yttrium, preferably ytterbium and / or yttrium.

7. A method for preparing a catalyst according to any one of claims 1-6, characterized in that, The preparation method includes the following steps: (1) The sulfate-containing support is contacted, impregnated and dried with a solution containing reforming active elements, and then optionally calcined to obtain a catalyst precursor. (2) Activate the catalyst precursor prepared in step (1), and then perform halogenation-reduction treatment on the activated catalyst precursor in the same step.

8. The preparation method according to claim 7, characterized in that, The halogenation-reduction treatment in step (2) includes: subjecting the activated catalyst precursor to halogenation-reduction treatment in the presence of hydrogen and gaseous halides, preferably, the gaseous halides being selected from aluminum chloride, aluminum bromide, aluminum fluoride, and ammonium chloride.

9. The preparation method according to any one of claims 7-8, characterized in that... In step (1), the solution containing the reforming active element comprises a soluble compound of a Group VIII metal, a soluble compound of a Group VIIB metal, and optionally a soluble compound of a rare earth metal element; preferably, the soluble compound of the Group VIII metal is selected from at least one of chloroplatinic acid, tetraammonium dichloroplatinate, ammonium chloroplatinate, platinum trichloride, platinum tetrachloride hydrate, platinum dicarbonyl dichloride, dinitrodiaminoplatinum, and sodium tetranitroplatinate; the soluble compound containing a Group VIIB metal is selected from at least one of perrhenic acid and ammonium perrhenate; the soluble compound containing a rare earth metal element is selected from at least one of rare earth metal element carbonates, rare earth metal element oxides, rare earth metal element nitrates, and rare earth metal element chlorides.

10. The preparation method according to any one of claims 7-8, characterized in that... The sulfate-containing carrier used in step (1) is sulfate-containing alumina, wherein the sulfate-containing carrier has a sulfate content of 0.3-3% by mass. The preparation method includes: neutralizing aluminate and aluminum ion donor in the presence of a solvent, aging and filtering to obtain aluminum hydroxide powder, calcining the aluminum hydroxide powder, contacting the calcined aluminum hydroxide powder with a sulfate-containing solution, and then optionally subjecting it to steam treatment.

11. The preparation method according to claim 10, characterized in that, The neutralization reaction between the aluminate and the aluminum ion donor is carried out in two steps. The conditions for the first step are: a pH of 6-10, a temperature of 50-80℃, and a time of 0.5-8 hours. The conditions for the second step are: a pH of 8-12, a temperature of 70-100℃, and a time of 1-12 hours, such that the relative crystallinity of the obtained aluminum hydroxide powder is not less than 58%, and / or the average grain size of the obtained aluminum hydroxide powder is 2-4 nm.

12. The preparation method according to any one of claims 7-11, characterized in that... The conditions for performing the halogenation-reduction treatment in step (2) include: a temperature of 450-550°C, a hydrogen / catalyst precursor volume ratio of 400-1400, and / or a halide / catalyst precursor mass ratio of 0.02-0.05, and a treatment time of 3-8 hours.

13. The application of the catalyst according to any one of claims 1-6 in naphtha catalytic reforming, which allows for improved aromatic selectivity in naphtha catalytic reforming.

14. A method for naphtha catalytic reforming, characterized in that... The method includes: contacting naphtha with hydrogen in the presence of a catalyst; wherein the catalyst is a catalyst according to any one of claims 1-6 or a catalyst prepared by any one of claims 7-12; and / or, the naphtha comprises straight-run naphtha with a distillation range of 40-230°C.

15. The method according to claim 14, characterized in that... The conditions for contacting naphtha with hydrogen in the presence of a catalyst include: a pressure of 0.1-9 MPa, a temperature of 370-600 °C, a hydrogen / hydrocarbon volume ratio of 800-2000, and / or a feed mass hourly space velocity of 0.1-18 h⁻¹. -1 .

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