Supported platinum, tin reforming catalysts, methods of making and using the same, and naphtha catalytic reforming processes

Abstract

The present application relates to supported platinum, tin reforming catalyst and its preparation method and application and naphtha catalytic reforming method. The supported platinum, tin reforming catalyst includes inorganic oxide carrier and the components with the content as follows: 0.1-1.0 mass% of platinum, 0.1-1.0 mass% of group IVA metal and 0.1-2.0 mass% of halogen, wherein the total amount of platinum in the surface layer of the catalyst accounts for 0.1-30% of the total amount of platinum in the catalyst, and the total amount of group IVA metal in the surface layer of the catalyst accounts for 25-70% of the total amount of group IVA metal in the catalyst; the surface layer of the carrier refers to the layer from the surface of the carrier to the inside of the carrier, the thickness of which accounts for 0.1-30% of the total thickness of the carrier. When used for catalytic reforming reaction, the catalyst of the application can significantly improve C5 + Liquid product yield, catalyst aromatic yield and carbon deposition rate are low.

Description

Technical Field

[0001] This invention relates to the field of reforming catalysts, specifically to a supported platinum and tin reforming catalyst, a method for preparing the supported platinum and tin reforming catalyst, the supported platinum and tin reforming catalyst prepared by the method and their applications, and a naphtha catalytic reforming method. Background Technology

[0002] Catalytic reforming is a process that uses naphtha as raw material to carry out hydrocarbon molecular structure rearrangement reactions under certain temperature, pressure, hydrogenation, and catalyst conditions to produce aromatics, high-octane reformed gasoline blending components, and hydrogen. It is one of the pillar technologies of modern oil refining and petrochemicals.

[0003] Catalytic reforming reactions require two different active sites: metallic sites and acidic sites. Metallic sites catalyze the hydrogenation and dehydrogenation of hydrocarbons, primarily provided by platinum; acidic sites catalyze the rearrangement of hydrocarbons, primarily provided by halogenated alumina.

[0004] In catalytic reforming, competing reactions occur simultaneously, including the dehydrogenation of cyclohexane to aromatics, the dehydrogenation and isomerization of alkylcyclohexane to aromatics, and the dehydrogenation and cyclization of cycloalkanes to aromatics. In these reactions, the gas produced by hydrogenation cracking leads to a decrease in gasoline yield, and coking accelerates catalyst deactivation. Frequent catalyst regeneration increases the operating costs of the unit. Therefore, developing highly active, highly selective, and low-coking-rate catalytic reforming catalysts has always been a goal. To improve the performance of Pt / Al₂O₃ catalysts, other metals are often used as promoters to modify the metal and acidic centers of the catalyst, further improving the catalyst's activity stability and selectivity, and extending its lifespan.

[0005] The common method for preparing Pt and Sn reforming catalysts is to introduce the desired metal components into the support in one step. In addition to Group VIII and Group IV metals, the introduced metal components usually contain rare earth elements.

[0006] CN1234455C describes a multi-metal catalyst and its preparation method. The catalyst comprises the following components by mass percentage: Group VIII metals 0.01-2.0%, Group IV metals 0.01-5.0%, Eu 0.01-10.0%, Ce 0.01-10.0%, halogens 0.10-10.0%, and inorganic oxides 63.00-99.86%. The method first prepares an inorganic oxide spherical support containing Group IVA metals through an oil-ammonia column forming process, with the tin component introduced in one step during the support forming process. A pre-prepared impregnation solution containing Eu and Ce components is then prepared. This solution contains a monoprotic inorganic acid at a concentration of 2-15% based on the carrier. After impregnation, the solution is dried and calcined. Then, an impregnation solution containing Group VIII metal compounds is prepared. This solution contains both organic and inorganic acids competing adsorbents. The solution is then dried, activated with water and chlorine, and reduced. The catalyst prepared by this method has a low coking rate and exhibits high activity and aromatic selectivity.

[0007] CN103372454B describes a multi-metal reforming catalyst comprising an inorganic oxide support and components with the following contents calculated based on the support: 0.01-2.0 wt% of platinum group metals, 0.01-5.0 wt% of group IV metals, 0.01-3.0 wt% of Sm, 0.01-3.0 wt% of Ce, and 0.1-5.0 wt% of halogens. This catalyst exhibits good activity stability and high selectivity. It also employs the method of introducing group IV metals during the support forming process, followed by the sequential introduction of rare earth additives and platinum group metals via impregnation.

[0008] CN103596681A describes a reforming catalyst and method for preparing spherical catalysts of platinum, tin, and cerium (or lanthanum) supported on an alumina support. Tin is incorporated into the alumina sol, and the tin-containing alumina sol is formed into 1.6 mm spheres by an oil droplet method. The atomic ratio of lanthanide metals to noble metals is less than 1.3:1. The lanthanide metals can be distributed such that the concentration of lanthanide metals in the 100-micron surface layer of the catalyst is less than twice the concentration of lanthanide metals in the core of the catalyst.

[0009] CN100338189C discloses a method for preparing a platinum-tin reforming catalyst. The catalyst comprises an inorganic oxide support and active components in the following proportions based on the support: 0.01-5.0% by mass of a Group VIII metal, 0.01-5.0% by mass of a Group IVA metal, 0-10.0% by mass of a lanthanide metal, and 0.1-10.0% by mass of a halogen. The method first prepares an inorganic oxide support containing a Group IVA metal, such that the content of the Group IVA metal in the support is 50%-70% of the total Group IVA metal content in the catalyst. Then, an impregnation solution containing a Group IVA metal compound and, with or without a lanthanide metal compound, is prepared to impregnate the support containing the Group IVA metal. The impregnation solution contains a monobasic inorganic acid with a concentration of 2-15% by mass based on the support. After impregnation, the support is dried and calcined. Then, an impregnation solution containing a Group VIII metal compound is prepared to impregnate the support, followed by drying and calcination. The catalyst prepared by this method has a low coking rate and high activity and aromatic selectivity.

[0010] The C5 of the catalyst disclosed in the above-mentioned prior art + The yield of liquid products and the yield of aromatic hydrocarbons from catalysts need to be further improved, and the rate of coking needs to be further reduced. Summary of the Invention

[0011] The purpose of this invention is to provide a supported platinum-tin reforming catalyst that, when used in catalytic reforming reactions, can significantly increase the C5 concentration. + The liquid product yield is high, the aromatic yield of the catalyst is high, and the coking rate is low.

[0012] A first aspect of the present invention provides a supported platinum-tin reforming catalyst, the catalyst comprising an inorganic oxide support and components in the following quantities calculated based on the support: 0.1-1.0% by mass of platinum, 0.1-1.0% by mass of Group IVA metals and 0.1-2.0% by mass of halogens, wherein the total amount of platinum in the surface layer of the support accounts for 0.1-30% of the total amount of platinum in the catalyst, and the total amount of Group IVA metals in the surface layer of the support accounts for 25-70% of the total amount of Group IVA metals in the catalyst; the surface layer of the support refers to a layer whose thickness from the surface of the support to the interior of the support is 0.1-30% of the total thickness of the support.

[0013] A second aspect of the present invention provides a method for preparing a supported platinum-tin reforming catalyst, the catalyst comprising an inorganic oxide support and components in the following quantities calculated based on the support: 0.1-1.0 wt% platinum, 0.1-1.0 wt% group IVA metals, and 0.1-2.0 wt% halogens, the preparation method comprising the following steps:

[0014] (1) Prepare an inorganic oxide support containing Group IVA metals, such that the content of Group IVA metals in the support is 20-80% of the total amount of Group IVA metals in the catalyst.

[0015] (2) The inorganic oxide carrier containing group IVA metals prepared in step (1) is impregnated with an impregnation solution containing group IVA metal compounds, platinum group metal compounds and monobasic inorganic acids, wherein the pure amount of monobasic inorganic acid is 1-15% of the carrier mass.

[0016] A third aspect of the present invention provides a supported platinum-tin reforming catalyst prepared by the method of the present invention described above.

[0017] The fourth aspect of the present invention provides the application of the above-described supported platinum and tin reforming catalyst of the present invention in catalytic reforming reactions.

[0018] A fifth aspect of the present invention provides a method for catalytic reforming naphtha, the method comprising: contacting naphtha with a supported platinum-tin reforming catalyst of the present invention and subjecting it to a catalytic reforming reaction.

[0019] The preparation method of the present invention first prepares an inorganic oxide support containing group IVA metals, and then introduces group IVA metals and Pt active components into the support simultaneously by impregnation. The group IVA metals are introduced into the catalyst system in two stages, and the group IVA metals and Pt show obvious enrichment on the surface of the support.

[0020] Furthermore, the catalyst prepared in this invention can significantly increase the C5 concentration when used in catalytic reforming reactions. + The liquid product yield is high, the aromatic yield of the catalyst is high, and the coking rate is low.

[0021] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0022] Figure 1 The catalyst cross-section electron probe microscopy (EPMA) analysis curves of Sn and Pt element distribution provided in Example 2 of this invention are shown, where the horizontal axis represents the diameter of the sphere in mm, and the vertical axis represents the signal intensity of Sn and Pt elements.

[0023] Figure 2 shows the Sn and Pt elemental distribution curves obtained by cross-sectional electron probe microscopy (EPMA) analysis of the catalyst provided in Comparative Example 3. Detailed Implementation

[0024] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present application will become clearer and more apparent.

[0025] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0026] A first aspect of the present invention provides a supported platinum-tin reforming catalyst comprising an inorganic oxide support and components in the following quantities calculated based on the support: 0.1-1.0 wt% platinum, 0.1-1.0 wt% group IVA metals and 0.1-2.0 wt% halogens, wherein the total amount of platinum in the surface layer of the support accounts for 0.1-30% of the total amount of platinum in the catalyst, and the total amount of group IVA metals in the surface layer of the support accounts for 25-70% of the total amount of group IVA metals in the catalyst, wherein the surface layer of the support refers to a layer whose thickness from the surface of the support to the interior of the support is 0.1-30% of the total thickness of the support.

[0027] In this invention, the inorganic oxide support is typically a porous, adsorbent material with an apparent bulk density of 0.5-0.8 g / mL, a pore volume of 0.4-1.0 mL / g, and a specific surface area of ​​150-250 m². 2 / g, preferably 180-220m 2 / g.

[0028] In this invention, the inorganic oxide is preferably alumina, and more preferably high-purity alumina with low impurity content. In the alumina, the Si and Fe content is less than 200 ppm, and the Na content is less than 100 ppm. The crystalline form of the alumina can be γ-Al₂O₃, η-Al₂O₃, or θ-Al₂O₃, with γ-Al₂O₃ being preferred.

[0029] In this invention, the carrier can be made into any shape known to those skilled in the art, such as spherical, sheet-like, strip-like, clover-shaped, etc. Spherical carriers can be prepared by oil-ammonia column molding, hot oil column molding, or water column molding, while strip-shaped or clover-shaped carriers can be prepared using conventional extrusion molding methods.

[0030] In this invention, the carrier can be defined as a surface layer and a core layer based on the different metal component contents. The carrier can be considered as a shell structure, with the surface layer being a coating layer of a certain thickness covering the core layer. The surface layer and the core layer together form the carrier in a concentric or coaxial manner, and the thickness of the surface layer is the same as the thickness of the coating layer. The thickness of the surface layer can vary depending on the radial dimension of the carrier. The content of platinum and Group IVA metal components in the surface layer is higher than that in the core layer, meaning that platinum and Group IVA metal components are enriched in the surface layer.

[0031] In this invention, the total thickness of the carrier refers to the distance from the surface of the carrier to its center. For a spherical carrier, the total thickness refers to the radius R of the spherical carrier. For non-spherical particulate carriers, they can be fitted to a sphere, and the total thickness refers to the fitted radius Rev = (3V / 4π). 1 / 3 Where V refers to the volume of the non-spherical particles. In one embodiment, the surface layer refers to a layer whose thickness from the surface of the carrier to the interior of the carrier is 0.1-30% (e.g., 10%, 20%, 25%) of the total thickness of the carrier.

[0032] According to a preferred embodiment, the carrier of the present invention is a spherical carrier. In this case, the surface layer specifically refers to a layer with a thickness of 0.1-30% (e.g., 10%, 20%, 25%) of the carrier radius from the surface of the carrier.

[0033] According to a specific embodiment of the present invention, the surface layer is a layer with a thickness of 0.01-0.3 mm from the surface of the carrier to the interior of the carrier, and platinum and Group IVA metal components are enriched in the 0.01-0.3 mm surface layer of the carrier.

[0034] According to a preferred embodiment of the present invention, the platinum content in the surface layer of the carrier within 0.01-0.3 mm accounts for 0.1-30% of the total platinum content in the carrier, and the tin content in the surface layer of the carrier within 0.01-0.3 mm accounts for 25-70% of the total tin content in the carrier.

[0035] In this invention, the elemental distribution in the catalyst can be analyzed using electron probe microscopy (EPMA) to obtain the elemental distribution curve of the catalyst cross-section. For example, Figure 1 The cross-sectional electron probe microanalysis (EPMA) analysis curves of the catalyst of Example 2 of this application show the distribution curves of Sn and Pt elements. The horizontal axis represents the diameter of the microspheres in mm, and the vertical axis represents the signal intensity of Sn and Pt elements. It can be seen that the signal intensity of Sn and Pt elements is basically uniformly distributed horizontally within the microsphere diameter range of 0.3-1.3 mm, while a significant increase in signal intensity is observed in the ranges of 0.01-0.3 mm and 1.3-1.6 mm, indicating that Sn and Pt elements are enriched on the surface of the microspheres.

[0036] The amounts of Sn and Pt elements in the surface layer can be quantitatively analyzed using an ESCALab250 X-ray photoelectron spectrometer manufactured by Thermo Fisher Scientific, while the total amount of Sn and Pt elements in the catalyst can be determined using an iCAP 6000 inductively coupled plasma atomic emission spectrometer manufactured by Thermo Fisher Scientific. Thus, the percentage of Sn and Pt elements in the surface layer relative to the total amount of Sn and Pt in the catalyst can be obtained.

[0037] In this invention, the active component platinum (Pt) in the catalyst can exist as a metal or as a compound, such as an oxide, sulfide, or halide. It can also exist chemically bonded to one or more components in the catalyst, or as an elemental metal. The catalyst contains 0.1-1.0% by mass of Pt, based on an elemental basis. According to a preferred embodiment of this invention, the catalyst contains 0.2-0.6% by mass of Pt, based on a spherical alumina support.

[0038] In this invention, the Group IVA metal is preferably tin (Sn). The Group IVA metal component in the catalyst can exist in a metallic state, or in the form of oxides, sulfides, halides, or oxyhalides. It can exist independently in the support, or in a physical or chemically bonded form with the support or other components. The catalyst contains 0.1-1.0% by mass of the Group IVA metal, based on an elemental basis. According to a preferred embodiment of the invention, the catalyst contains 0.2-0.6% by mass of the Group IVA metal, based on a spherical alumina support.

[0039] In addition to the metal component, the catalyst of the present invention also contains halogens. The preferred halogen is chlorine. The catalyst contains 0.1-2.0% by mass of halogen, based on the elemental composition and the spherical alumina support. According to a preferred embodiment of the present invention, the catalyst contains 0.5-1.5% by mass of halogen, based on the spherical alumina support.

[0040] According to a preferred embodiment of the present invention, the inorganic oxide support containing Group IVA metals is a tin-containing γ-Al₂O₃ spherical support. The particle size of the tin-containing γ-Al₂O₃ spherical support is 1.4-2.0 mm.

[0041] A second aspect of the present invention provides a method for preparing a supported platinum-tin reforming catalyst, the catalyst comprising an inorganic oxide support and components in the following quantities calculated based on the support: 0.1-1.0 wt% platinum, 0.1-1.0 wt% group IVA metals, and 0.1-2.0 wt% halogens, the preparation method comprising the following steps:

[0042] (1) Prepare an inorganic oxide support containing Group IVA metals, such that the content of Group IVA metals in the support is 20-80% of the total amount of Group IVA metals in the catalyst.

[0043] (2) The inorganic oxide carrier containing group IVA metals prepared in step (1) is impregnated with an impregnation solution containing group IVA metal compounds, platinum group metal compounds and monobasic inorganic acids. The pure amount of monobasic inorganic acid is 1-15% of the carrier mass.

[0044] In this invention, the inorganic oxide support is typically a porous, adsorbent material with an apparent bulk density of 0.5-0.8 g / mL, a pore volume of 0.4-1.0 mL / g, and a specific surface area of ​​150-250 m². 2 / g, preferably 180-220m 2 / g.

[0045] In this invention, the inorganic oxide is preferably alumina, and more preferably high-purity alumina with low impurity content. In the alumina, the Si and Fe content is less than 200 ppm, and the Na content is less than 100 ppm. The crystalline form of the alumina can be γ-Al₂O₃, η-Al₂O₃, or θ-Al₂O₃, with γ-Al₂O₃ being preferred.

[0046] In this invention, the carrier can be made into any shape known to those skilled in the art, such as spherical, sheet-like, strip-like, or clover-shaped. Spherical carriers can be prepared by oil-ammonia column molding, hot oil column molding, or water column molding, while strip-shaped or clover-shaped carriers can be prepared using conventional extrusion molding methods. According to a preferred embodiment, the inorganic oxide carrier of this invention is a spherical carrier.

[0047] In this invention, the active component platinum (Pt) in the catalyst can exist as a metal or as a compound, such as an oxide, sulfide, or halide. It can also exist chemically bonded to one or more components in the catalyst, or as an elemental metal. The catalyst contains 0.1-1.0% by mass of Pt. According to a preferred embodiment of the invention, the catalyst contains 0.2-0.6% by mass of Pt.

[0048] In this invention, the Group IVA metal is preferably tin (Sn). The Group IVA metal component in the catalyst can exist in a metallic state, or in the form of oxides, sulfides, halides, or oxyhalides. It can exist independently in the support, or in a physical or chemically bonded form with the support or other components. The catalyst contains 0.1-1.0% by mass of the Group IVA metal, based on the elemental composition. According to a preferred embodiment of the invention, the catalyst contains 0.2-0.6% by mass of the Group IVA metal, based on the elemental composition.

[0049] In step (1) of the present invention, the content of the IVA metal in the prepared inorganic oxide support containing IVA metal is 20-80% of the total amount of IVA metal in the catalyst, preferably 25-70%.

[0050] In addition to the metal component, the catalyst of the present invention also contains a halogen. The halogen is preferably chlorine. The catalyst contains 0.1-2.0% by mass of halogen, based on elemental composition. According to a preferred embodiment of the present invention, the catalyst contains 0.5-1.5% by mass of halogen.

[0051] In the preparation method of the present invention, the Group IVA metal in step (1) can be introduced into the support by means of co-precipitation, co-gelation, ion exchange, or impregnation with the porous support. Preferably, the support containing Group IVA metal is prepared by co-gelation, and more preferably, a γ-Al₂O₃ support containing Sn is prepared. The preparation method is as follows:

[0052] Alumina sol was prepared by acidifying boehmite powder and tin compounds. A gelling agent was added to the sol, and the mixture was dripped into a hot oil column to form spheres. After washing, drying and calcining, γ-Al2O3 carrier microspheres containing Sn were obtained.

[0053] According to a preferred embodiment, the particle size of the tin-containing γ-Al2O3 spherical carrier of the present invention is 1.4-2.0 mm.

[0054] In the preparation method of this invention, the aluminum source compound for preparing the aluminum sol is high-purity boehmite, which can be obtained by aluminum sulfate-sodium aluminate, sodium aluminate-CO2, C3-C4... 10 It is prepared by one or more routes of hydrolysis of high-carbon alkoxyaluminum. The tin compound is selected from compounds that can form soluble or dispersible sols, such as their chlorides, oxides, hydroxides, or oxychlorides, wherein the tin compound is preferably stannous chloride or stannous tetrachloride. The alumina suspension formed by mixing boehmite, the tin compound, and water and stirring evenly has a solid content of 15-30% by mass, preferably 18-25% by mass, based on alumina.

[0055] This invention prepares alumina sol by adding an acid solution to an alumina suspension. The acid can be tartaric acid, lactic acid, citric acid, formic acid, acetic acid, nitric acid, hydrochloric acid, or perchloric acid, preferably nitric acid or hydrochloric acid. The added acid preferably accounts for 0.5-15% of the dry basis weight of the boehmite, more preferably 2-12%.

[0056] In this invention, the gelling agent can be hexamethylenetetramine, and the ratio of the gelling agent to alumina on a dry basis can be (0.5-50):100, preferably (1.0-20):100.

[0057] In this invention, the oil phase in the hot oil column can be selected from at least one of kerosene, medical lubricating oil, liquid paraffin oil, and white oil, preferably liquid paraffin oil, wherein the liquid paraffin is a C44-carbon oil with a distillation range of 250–500 °C. 16 ~C 20 n-alkanes.

[0058] In this invention, the temperature of the hot oil column phase can be 80-110℃, preferably 85-105℃, and the thickness of the hot oil column phase can be 100-800 cm, preferably 200-600 cm. The formed pellets need to be washed, dried, and calcined. The drying temperature can be 80-150℃, preferably 100-120℃, and the time can be 0.5-24 hours, preferably 4-12 hours. The calcination temperature can be 400-800℃, preferably 500-650℃, and the time can be 0.5-24 hours, preferably 2-8 hours.

[0059] In step (2) of the present invention, the IVA group metal and Pt metal components are introduced by impregnation method, preferably by co-impregnation method, that is, the impregnation solution used for impregnation contains soluble IVA group metal components and soluble platinum-containing compounds.

[0060] The impregnation solution in step (2) contains at least one monobasic inorganic acid, such as hydrochloric acid, nitric acid, oxalic acid, citric acid, and tartaric acid, preferably hydrochloric acid. Its pure amount is 1-15% by mass of the carrier. Here, pure amount refers to the amount of the pure monobasic inorganic acid substance used, excluding the amount of solvent such as water when using the monobasic inorganic acid solution.

[0061] The soluble platinum-containing compound may be selected from at least one of chloroplatinic acid, ammonium chloroplatinate, bromoplatinic acid, platinum trichloride, and platinum tetrachloride hydrate, preferably chloroplatinic acid.

[0062] In the preparation method of the present invention, the impregnation is preferably a supersaturated impregnation method, the liquid / solid volume ratio of the impregnation is preferably greater than 1, more preferably (1-3):1, the impregnation temperature can be 10-90°C, and the excess liquid after impregnation can be removed by rotary evaporation.

[0063] In this invention, the preparation method further includes drying, water-halogen adjustment and reduction treatment after step (2).

[0064] To ensure the catalyst has suitable acidity, after introducing the metal component, a sufficient amount of halogen is introduced into the catalyst using a water-halogen conditioning method. The water-halogen conditioning method involves treating the catalyst with a gas containing halogen and water, preferably with air containing halogen and water. The water-halogen conditioning temperature can be 370-700℃, preferably 450-650℃; the molar ratio of water to halogen used during conditioning is (1.0-100):1, preferably (10-100):1, more preferably (10-80):1; the conditioning time is 1-16 h, preferably 2-8 h.

[0065] The halogen used for water-halogen conditioning is preferably chlorine; in this case, water-halogen conditioning can be referred to as water chlorination treatment. The chlorine-containing compound used for conditioning is preferably Cl2, HCl, or an organic compound that can decompose to release chlorine, such as dichloromethane, trichloromethane, carbon tetrachloride, dichloroethylene, trichloroethylene, or perchloroethylene, preferably at least one of dichloroethylene and perchloroethylene.

[0066] The catalyst prepared by the method of the present invention, after adjusting the halogen content, needs to be reduced before use to reduce the metal components to the metallic state of the corresponding elements. The reducing gas can be H2, CO, or other reducing gases, preferably H2. The hydrogen can be pure hydrogen or a mixture of hydrogen and an inert gas, preferably nitrogen, argon, or helium. If a mixture is used, the suitable hydrogen volume content is 1.0-99%, preferably 10-60%. The reduction temperature can be 250-650℃, preferably 400-600℃, and the reduction time is 0.5-16 h, preferably 2-8 h.

[0067] A third aspect of the present invention provides a supported platinum-tin reforming catalyst prepared by the above-described preparation method.

[0068] The supported platinum and tin reforming catalyst prepared by the method of the present invention has a total platinum content of 0.1-30% in the surface layer of the support and a total IVA metal content of 25-70% in the surface layer of the support. The surface layer of the support refers to the layer whose thickness from the surface of the support to the interior of the support is 0.1-30% of the total thickness of the support.

[0069] According to a preferred embodiment of the present invention, platinum and Group IVA metal components are enriched within 0.01-0.3 mm of the surface layer of the carrier.

[0070] The fourth aspect of the present invention provides the application of the above-described supported platinum and tin reforming catalyst of the present invention in catalytic reforming reactions.

[0071] A fifth aspect of the present invention provides a method for catalytic reforming naphtha, the method comprising: contacting naphtha with a supported platinum-tin reforming catalyst provided by the present invention and carrying out a catalytic reforming reaction.

[0072] In this invention, the conditions for the catalytic reforming reaction may include: a temperature of 360-600℃, preferably 450-580℃; a pressure of 0.1-2.5 MPa, preferably 0.2-1.0 MPa; and a volume hourly space velocity (VHSV) of 1-20 h⁻¹ for the feed liquid. -1 Preferably 1-10h -1 The hydrogen / hydrocarbon volume ratio is 500-2000, preferably 700-1500.

[0073] The invention is further illustrated by the following examples, but the invention is not limited thereto.

[0074] In the examples and comparative examples, the crushing strength of alumina pellets was measured using a ZQJ intelligent particle strength testing machine manufactured by Dalian Equipment Diagnostic Instrument Factory, with a force application rate of 5 N / s and a range of 250 N.

[0075] The specific surface area and pore volume of alumina microspheres were determined using a low-temperature nitrogen adsorption method on a Micromeritics ASAP2400 instrument. The specific surface area was calculated using the BET method, and the pore volume was calculated when the relative pressure P / P0 was 0.99. P is the measurement pressure, and P0 is the saturated vapor pressure of N2 at the adsorption temperature. The pore size distribution of the sample was calculated using desorption curves.

[0076] The elemental distribution of Sn and Pt in the catalyst was obtained by electron probe microscopy (EPMA) analysis. A FEIQuanta 200 field emission scanning electron microscope was used, combined with energy dispersive spectroscopy (EDS) to characterize the elemental distribution in the catalyst micro-regions. The radial distribution of elements along the catalyst particles was obtained using the line scanning function of SEM-EDS.

[0077] Example 1

[0078] (1) Preparation of aluminum hydroxide sol containing 0.1% by mass of Sn

[0079] Take 133.4g of pseudoboehmite powder USA (produced by Yantai Heng Hui Chemical Co., Ltd., China, with a specific surface area of ​​250m²). 2 / g, N2 adsorption method pore volume 0.56mL / g, dry basis mass of 100g), 0.19g SnCl2·2H2O and appropriate amount of deionized water, stirred to form a suspension with a solid content of 20% by mass based on alumina, stirred for 0.5h, 15.0g of 20% by mass nitric acid solution was added dropwise, stirred for 2h, and then 30g of kerosene and 3.0g of fatty alcohol polyoxyethylene ether were added and stirred for 1h to form aluminum hydroxide sol, with a slurry viscosity of 20s.

[0080] (2) Hot oil column forming

[0081] The oil phase of the hot oil column was liquid paraffin (provided by Sinopharm Chemical Reagent Beijing Co., Ltd.), the oil bath temperature was 98℃, and the oil phase thickness was 250cm. Alumina sol and 6.7g of a 30% by mass hexamethylenetetramine solution were mixed and stirred for 0.5h, then dropped into the hot oil column to form spheres. The spheres were directly removed from the bottom of the apparatus, washed with water, dried at 110℃ for 4h, and calcined at 600℃ for 4h to obtain the finished γ-Al₂O₃ microspheres. Their particle diameter, crushing strength, specific surface area, and elemental content are shown in Table 1.

[0082] (3) Platinum

[0083] Take 50.8 mL of chloroplatinic acid solution with a platinum concentration of 5.7 mg / mL, add 0.38 g of SnCl2·2H2O, 24 mL of hydrochloric acid solution with a concentration of 100 mg / mL, and an appropriate amount of water. The liquid / solid volume ratio during impregnation is 1.2. After shaking for 0.5 h, add 100 g of the support prepared in step (2) and let it stand for 12 h for impregnation. Evaporate the filtrate to dryness and dry it at 90 °C for 10 h. At 650 °C, chlorine activation is performed by passing air containing HCl and water through it for 6 h. The water / HCl molar ratio in the air is 60:1. Then, reduce it in hydrogen at 550 °C for 6 h to obtain reduced catalyst A. Its active components are shown in Table 1. The metal component content in Table 1 is determined by X-ray fluorescence method, and the chlorine content is determined by electrode method.

[0084] (4) Evaluation of the performance of n-heptane reforming reaction

[0085] In a microreactor, 2 mL of catalyst A was loaded, the reaction temperature was 500 °C, the reaction pressure was 0.35 MPa, the hydrogen / hydrocarbon volume ratio was 800, and the liquid hourly space velocity (LHSV) was 2.0 h⁻¹. -1 The average reaction results after a cumulative reaction time of 100 h are shown in Table 2. After 48 h of reaction, samples were taken every 24 h, and the bed temperature was measured at the same time to investigate the change of catalyst selectivity with reaction time. The amount of catalyst coke after the reaction was measured using an EMIA-820V infrared sulfur and carbon analyzer from HORIBA Corporation of Japan, and the results are listed in Table 3.

[0086] Example 2

[0087] (1) Preparation of aluminum hydroxide sol containing 0.2% by mass of Sn

[0088] Take 133.4g of pseudoboehmite powder USA (produced by Yantai Heng Hui Chemical Co., Ltd., China, with a specific surface area of ​​250m²). 2 / g, N2 adsorption method pore volume 0.56mL / g, dry basis mass of 100g), 0.38g SnCl2·2H2O and appropriate amount of deionized water, stirred to form a suspension with a solid content of 20% by mass based on alumina, stirred for 0.5h, 14.7g of 20% by mass nitric acid solution was added dropwise, stirred for 2h, and then 30g kerosene and 3.0g fatty alcohol polyoxyethylene ether were added and stirred for 1h to form aluminum hydroxide sol, with a slurry viscosity of 21s.

[0089] (2) Hot oil column forming

[0090] Sn-containing alumina microspheres were prepared by hot oil column molding in step (2) of Example 1. The microspheres were washed with water, dried at 110°C for 4 hours, and calcined at 600°C for 4 hours to obtain finished alumina microspheres. The particle diameter, crushing strength, specific surface area and element content are shown in Table 1.

[0091] (3) Platinum

[0092] Take 50.8 mL of chloroplatinic acid solution with a platinum concentration of 5.7 mg / mL, add 0.19 g of SnCl2·2H2O, 26 mL of hydrochloric acid solution with a concentration of 100 mg / mL, and an appropriate amount of water. The liquid / solid volume ratio during impregnation is 1.2. After shaking for 0.5 h, add 100 g of the support prepared in step (2) and let it stand for 12 h for impregnation. Evaporate the filtrate to dryness, dry at 90 °C for 10 h, and activate with chlorine by passing air containing HCl and water at 650 °C for 6 h. The water / HCl molar ratio in the air is 60:1. Then reduce in hydrogen at 550 °C for 6 h to obtain reduced catalyst B. Its active components are shown in Table 1.

[0093] Figure 1 The catalyst cross-section electron probe microanalysis (EPMA) analysis curves of Sn and Pt elements provided in Example 2 of this invention are shown. The horizontal axis represents the diameter of the microsphere (mm), and the vertical axis represents the signal intensity of Sn and Pt elements. It can be seen that the signal intensity of Sn and Pt elements is basically uniformly distributed horizontally within the microsphere diameter range of 0.3-1.3 mm, while a significant increase in signal intensity is observed in the ranges of 0-0.3 mm and 1.3-1.6 mm, indicating that Sn and Pt elements are enriched on the surface of the microsphere.

[0094] Calculations show that the total amount of platinum in the surface layer of the catalyst accounts for 18.6% of the total amount of platinum in the catalyst, and the total amount of tin in the surface layer of the catalyst accounts for 30.5% of the total amount of tin in the catalyst. The surface layer of the support refers to the layer from the surface of the support to the interior of the support, which is 20% of the total thickness of the support (i.e., the radius of the sphere), as shown in Table 2.

[0095] (4) Evaluation of the performance of n-heptane reforming reaction

[0096] The performance of the catalyst in the n-heptane reforming reaction was investigated in a micro-reaction evaluation device using the same method as in step (4) of Example 1, except that catalyst B was used instead of catalyst A. The reaction results are shown in Table 3.

[0097] Example 3

[0098] (1) Preparation of aluminum hydroxide sol containing 0.15% by mass of Sn

[0099] Take 133.4g of pseudoboehmite powder USA (produced by Yantai Heng Hui Chemical Co., Ltd., China, with a specific surface area of ​​250m²). 2 / g, N2 adsorption method pore volume 0.56mL / g, dry basis mass of 100g), 0.285g SnCl2·2H2O and appropriate amount of deionized water, stirred to form a suspension with a solid content of 20% by mass based on alumina, stirred for 0.5h, 14.7g of 20% by mass nitric acid solution was added dropwise, stirred for 2h, and then 30g kerosene and 3.0g fatty alcohol polyoxyethylene ether were added and stirred for 1h to form aluminum hydroxide sol, with a slurry viscosity of 21s.

[0100] (2) Hot oil column forming

[0101] Sn-containing alumina microspheres were prepared by hot oil column molding in step (2) of Example 1. The microspheres were washed with water, dried at 110°C for 4 hours, and calcined at 600°C for 4 hours to obtain finished alumina microspheres. The particle diameter, crushing strength, specific surface area and element content are shown in Table 1.

[0102] (3) Platinum

[0103] Take 101.6 mL of chloroplatinic acid solution with a platinum concentration of 5.7 mg / mL, add 0.285 g of SnCl2·2H2O, 26 mL of hydrochloric acid solution with a concentration of 100 mg / mL, and an appropriate amount of water. The liquid / solid volume ratio during impregnation is 1.2. After shaking for 0.5 h, add 100 g of the support prepared in step (2) and let it stand for 12 h for impregnation. Evaporate the filtrate to dryness, dry at 90 °C for 10 h, and activate with chlorine by passing air containing HCl and water at 650 °C for 6 h. The water / HCl molar ratio in the air is 40:1. Then reduce in hydrogen at 550 °C for 6 h to obtain the reduced catalyst C. Its active components are shown in Table 1.

[0104] (4) Evaluation of the performance of n-heptane reforming reaction

[0105] The performance of the catalyst in the n-heptane reforming reaction was investigated in a micro-reaction evaluation device using the same method as in step (4) of Example 1, except that catalyst C was used instead of catalyst A. The reaction results are shown in Table 3.

[0106] Comparative Example 1

[0107] (1) Preparation of Sn-free aluminum hydroxide sol

[0108] Take 133.4g of pseudoboehmite powder USA (produced by Yantai Heng Hui Chemical Co., Ltd., China, with a specific surface area of ​​250m²). 2 / g, N2 adsorption method pore volume 0.56mL / g, dry basis mass of 100g) and appropriate amount of deionized water, stir to form a suspension with a solid content of 20% by mass based on alumina, stir for 0.5h, add 15.6g of 20% by mass nitric acid solution dropwise, stir for 2h, add 30g kerosene and 3.0g fatty alcohol polyoxyethylene ether and stir for 1h to form aluminum hydroxide sol, the viscosity of the slurry is 18s.

[0109] (2) Hot oil column forming

[0110] The oil phase of the hot oil column was liquid paraffin (provided by Sinopharm Chemical Reagent Beijing Co., Ltd.), the oil bath temperature was 98℃, and the oil phase thickness was 250cm. Alumina sol and 6.7g of a 30% by mass hexamethylenetetramine solution were mixed and stirred for 0.5h, then dropped into the hot oil column to form spheres. The spheres were directly removed from the bottom of the apparatus, washed with water, dried at 110℃ for 2h, and calcined at 600℃ for 4h to obtain γ-Al₂O₃ microspheres. Their particle diameter, crushing strength, specific surface area, and elemental content are shown in Table 1.

[0111] (3) Platinum

[0112] Take 50.8 mL of chloroplatinic acid solution with a platinum concentration of 5.7 mg / mL, add 0.59 g of SnCl2·2H2O, 24 mL of hydrochloric acid solution with a concentration of 100 mg / mL, and an appropriate amount of water. The liquid / solid volume ratio during impregnation is 1.2. After shaking for 0.5 h, add 100 g of the support prepared in step (2) and let it stand for 12 h for impregnation. Evaporate the filtrate to dryness, dry at 90 °C for 10 h, and activate with chlorine by passing air containing HCl and water at 650 °C for 6 h. The water / HCl molar ratio in the air is 60:1. Then reduce in hydrogen at 550 °C for 6 h to obtain the reduced catalyst DA1. Its active components are shown in Table 1.

[0113] (4) Evaluation of the performance of n-heptane reforming reaction

[0114] The performance of the catalyst in the n-heptane reforming reaction was investigated in a micro-reaction evaluation device using the same method as in step (4) of Example 1, except that catalyst DA1 was used instead of catalyst A. The reaction results are shown in Table 3.

[0115] Comparative Example 2

[0116] (1) Preparation of aluminum hydroxide sol containing 0.30% by mass of Sn

[0117] Take 133.4g of pseudoboehmite powder USA (produced by Yantai Heng Hui Chemical Co., Ltd., China, with a specific surface area of ​​250m²). 2 / g, N2 adsorption method pore volume 0.56mL / g, dry basis mass of 100g), 0.59g SnCl2·2H2O and appropriate amount of deionized water, stirred to form a suspension with a solid content of 20% by mass based on alumina, stirred for 0.5h, 14.0g of 20% by mass nitric acid solution was added dropwise, stirred for 2h, and then 30g of kerosene and 3.0g of fatty alcohol polyoxyethylene ether were added and stirred for 1h to form aluminum hydroxide sol, with a slurry viscosity of 24s.

[0118] (2) Hot oil column forming

[0119] Sn-containing alumina microspheres were prepared by hot oil column molding according to step (2) of Example 1. The microspheres were washed with water, dried at 110 ℃ for 4 h, and calcined at 600 ℃ for 4 h to obtain finished alumina microspheres. The particle diameter, crushing strength, specific surface area and element content are shown in Table 1.

[0120] (3) Platinum

[0121] Take 50.8 mL of chloroplatinic acid solution with a platinum concentration of 5.7 mg / mL, add 24 mL of hydrochloric acid solution with a concentration of 100 mg / mL and an appropriate amount of water. The liquid / solid volume ratio during impregnation is 1.2. After shaking for 0.5 h, add 100 g of the support prepared in step (2) and let it stand for 12 h for impregnation. Evaporate the filtrate to dryness, dry at 90 °C for 10 h, and activate with chlorine by passing air containing HCl and water at 650 °C for 6 h. The water / HCl molar ratio in the air is 60:1. Then reduce in hydrogen at 550 °C for 6 h to obtain the reduced catalyst DA2. Its active components are shown in Table 1.

[0122] (4) Evaluation of the performance of n-heptane reforming reaction

[0123] The performance of the catalyst in the n-heptane reforming reaction was investigated in a micro-reaction evaluation device according to step 1(4) of Example 1, except that catalyst DA2 was used instead of catalyst A. The reaction results are shown in Table 3.

[0124] Comparative Example 3

[0125] (1) Preparation of aluminum hydroxide sol containing 0.1% by mass of Sn

[0126] The preparation was carried out in the same manner as step (1) of Example 1.

[0127] (2) Hot oil column forming

[0128] γ-Al2O3 microspheres were prepared in the same manner as step (2) of Example 1. The particle diameter, crushing strength, specific surface area and element content are shown in Table 1.

[0129] (3) Draw the remaining tin

[0130] Take 0.38g SnCl2·2H2O, add 24mL of concentrated hydrochloric acid solution with a mass concentration of 37.5% and an appropriate amount of water. The liquid / solid volume ratio during impregnation is 1.2. After shaking for 0.5h, add 100g of the carrier prepared in step (2) and let it stand for 12h for impregnation. Evaporate the filtrate to dryness and dry it at 90℃ for 10h.

[0131] (4) Platinum

[0132] Take 50.8 mL of chloroplatinic acid solution with a platinum concentration of 5.7 mg / mL, add 24 mL of hydrochloric acid solution with a concentration of 100 mg / mL and an appropriate amount of water. The liquid / solid volume ratio during impregnation is 1.2. After shaking for 0.5 h, add 100 g of the support prepared in step (3) and let it stand for 12 h for impregnation. Evaporate the filtrate to dryness and dry at 90 °C for 10 h. At 650 °C, activate with chlorine by passing air containing HCl and water for 6 h. The water / HCl molar ratio in the air is 60:1. Then reduce in hydrogen at 550 °C for 6 h to obtain the reduced catalyst DA3. Its active components are shown in Table 1.

[0133] Figure 2 shows the Sn and Pt elemental distribution curves obtained by cross-sectional electron probe microscopy (EPMA) analysis of the catalyst provided in Comparative Example 3. The horizontal axis represents the diameter of the sphere (mm), and the vertical axis represents the signal intensity of Sn and Pt elements. (Comparison) Figure 1 And Figure 2 shows that: Figure 1 The signal intensities of Sn and Pt elements in the microspheres are basically uniformly distributed horizontally within the diameter range of 0.3-1.3 mm, while a significant increase in signal intensity is observed in the ranges of 0.01-0.3 mm and 1.3-1.6 mm, indicating that Sn and Pt elements are enriched on the surface of the microspheres. Figure 2 shows that the signal intensities of Sn and Pt elements are uniformly distributed within the alumina microspheres within the diameter range of 0.01-1.6 mm.

[0134] (5) Evaluation of the performance of n-heptane reforming reaction

[0135] The performance of the catalyst in the n-heptane reforming reaction was investigated in a micro-reaction evaluation device using the same method as in step (4) of Example 1, except that catalyst DA3 was used instead of catalyst A. The reaction results are shown in Table 3.

[0136] Test Example 1

[0137] Evaluation of naphtha reforming reaction performance

[0138] In a 100 mL apparatus, 50 mL of catalysts AC and DA1-DA3 were respectively loaded. The catalysts were evaluated using naphtha as feedstock. The properties of the naphtha are shown in Table 4. The evaluation conditions were: reaction temperature 530℃, reaction pressure 0.7 MPa, hydrogen / hydrocarbon volume ratio 1000, and liquid hourly space velocity (LISH) 1.8 h⁻¹. -1 The cumulative reaction time was 120 hours. During the reaction, the temperature of the reaction die was maintained at C5 by adjusting the temperature of the die. + The octane number (RON) of the liquid product was kept constant at 103. The reaction results are shown in Table 5.

[0139] Table 1

[0140]

[0141] Table 2

[0142] serial number Surface layer Pt content, % Sn content in the surface layer, % 1 27.1 61.4 2 18.6 30.5 3 23.4 48.4 DA1 53.6 90.6 DA2 0.7 0.5 DA3 0.4 10.2

[0143] The surface layer Pt content refers to the proportion of the total amount of platinum in the surface layer of the catalyst to the total amount of platinum in the catalyst.

[0144] The surface layer Sn content refers to the total amount of Sn in the surface layer of the catalyst relative to the total amount of tin in the catalyst.

[0145] The surface layer of a carrier refers to the layer whose thickness from the surface of the carrier to the interior of the carrier is 20% of the total thickness of the carrier (i.e., the radius of a spherical carrier).

[0146] Table 3

[0147]

[0148] Table 4

[0149]

[0150] Table 5

[0151]

[0152] As can be seen from the results in Tables 3 and 5, the catalysts prepared in Examples 1-3, compared with those prepared in Comparative Examples 1-3, can significantly increase the C5 value in n-heptane or naphtha reforming reactions. + The catalyst achieves high aromatic yield while maintaining a high aromatic content in the liquid product, and at the same conversion conditions, the catalyst has a low coking rate.

[0153] The present application has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present application based on these embodiments, all of which fall within the protection scope of the present application.

Claims

1. A supported platinum-tin reforming catalyst, comprising an inorganic oxide support and components in the following quantities calculated based on the support: 0.1-1.0 wt% platinum, 0.1-1.0 wt% Group IVA metals, and 0.1-2.0 wt% halogens, wherein, The total amount of platinum in the surface layer of the catalyst accounts for 18.6-30% of the total platinum in the catalyst, and the total amount of Group IVA metals in the surface layer of the catalyst accounts for 25-70% of the total Group IVA metals in the catalyst; the surface layer of the support refers to the layer from the surface of the support to the interior of the support, whose thickness accounts for 10-25% of the total thickness of the support.

2. The catalyst according to claim 1, wherein the surface layer is a layer with a thickness of 0.01-0.3 mm from the surface of the support to the interior of the support.

3. The catalyst according to claim 1, wherein, The catalyst contains 0.2-0.6% by mass of platinum, 0.2-0.6% by mass of Group IVA metals and 0.5-1.5% by mass of halogens.

4. The catalyst according to claim 1, wherein, The inorganic oxide is aluminum oxide.

5. The catalyst according to claim 4, wherein, The inorganic oxide carrier is spherical.

6. The catalyst according to claim 1, wherein, The IVA group metal is tin, and the halogen is chlorine.

7. The catalyst according to claim 1, wherein, The inorganic oxide support containing Group IVA metals is a tin-containing γ-Al₂O₃ spherical support.

8. The catalyst according to claim 7, wherein, The particle size of the tin-containing γ-Al2O3 spherical support is 1.4-2.0 mm.

9. A method for preparing a supported platinum-tin reforming catalyst, the catalyst comprising an inorganic oxide support and components in the following quantities calculated based on the support: 0.1-1.0 wt% platinum, 0.1-1.0 wt% group IVA metals, and 0.1-2.0 wt% halogens, characterized in that, The preparation method includes the following steps: (1) Prepare an inorganic oxide support containing Group IVA metals, such that the content of Group IVA metals in the support is 20-80% of the total amount of Group IVA metals in the catalyst. (2) The inorganic oxide carrier containing group IVA metals prepared in step (1) is impregnated with an impregnation solution containing group IVA metal compounds, platinum group metal compounds and monobasic inorganic acids, wherein the pure amount of monobasic inorganic acid is 1-15% of the carrier mass.

10. The preparation method according to claim 9, wherein, The inorganic oxide support containing Group IVA metals is a tin-containing γ-Al₂O₃ spherical support.

11. The preparation method according to claim 10, wherein, The tin-containing γ-Al2O3 spherical carrier has a particle size of 1.4-2.0 mm and is prepared by hot oil column droplet forming method.

12. The preparation method according to claim 9, wherein, The preparation method also includes drying, water-halogen adjustment and reduction treatment after step (2).

13. The preparation method according to claim 12, wherein, Sufficient halogen is introduced into the catalyst using a water-halogen conditioning method. The water-halogen conditioning conditions include: temperature 370-700℃, time 1-16 hours; and the molar ratio of water to halogen used during conditioning is (10-100):

1.

14. The preparation method according to claim 12, wherein, The conditions for the reduction treatment include: temperature 300-600℃, time 0.5-16 hours.

15. The supported platinum-tin reforming catalyst prepared by the method according to any one of claims 9-12.

16. The application of the supported platinum-tin reforming catalyst according to any one of claims 1-7 or 15 in catalytic reforming reactions.

17. A method for catalytic reforming of naphtha, characterized in that, The catalytic reforming method includes contacting naphtha with the supported platinum-tin reforming catalyst as described in any one of claims 1-7 or 15 and carrying out a catalytic reforming reaction.

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