CN109692696B

CN109692696B - Reforming catalyst and preparation method and application thereof

Info

Publication number: CN109692696B
Application number: CN201710996035.9A
Authority: CN
Inventors: 刘建良; 马爱增; 王春明; 潘锦程; 王国成
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2017-10-23
Filing date: 2017-10-23
Publication date: 2022-03-11
Anticipated expiration: 2037-10-23
Also published as: CN109692696A

Abstract

The invention relates to a reforming catalyst, a preparation method and application thereof, wherein the reforming catalyst comprises SiO-containing₂The alumina pellet carrier and active components with the following contents based on alumina in the carrier: platinum 0.01-2.4 wt%, IVA group metal 0.1-3.5 wt%, halogen 0.1-2.4 wt%, and SiO₂The SiO in the alumina pellet carrier based on alumina₂The content is 0.01-3.5% by mass. The reforming catalyst provided by the invention has high hydrothermal stability and high liquefied gas yield.

Description

Reforming catalyst and preparation method and application thereof

Technical Field

The invention relates to a reforming catalyst, a preparation method thereof and a naphtha catalytic reforming method.

Background

Alumina has excellent characteristics such as high specific surface area, narrow particle size distribution, good adsorptivity, thermal stability, surface acidity and the like, and is widely used as a carrier, an adsorbent, a hydrogenation catalyst and the like of a petrochemical catalyst. Researches show that the bulk property of the alumina can be effectively modulated by adding a proper amount of silica into the alumina. After silicon element is introduced in the early stage of alumina preparation, the alumina carrier can be obviously improved

The number of acid sites is very favorable for acid-catalyzed reactions.

For a long time, the problem of material competition between naphtha reforming and ethylene cracking devices exists, after western gas is transported from home to east, liquefied gas which is mostly used as fuel in the past is competed by cheap and environment-friendly natural gas, the market is gradually saturated, the price of liquefied gas in the home market is lower than that of naphtha, and the liquefied gas is often used as an ethylene cracking raw material. Whether liquefied gas or aromatic hydrocarbon can be produced in the process of naphtha reforming or not is achieved, and a refining and chemical integration layout of 'alkene is preferably adopted, arene is preferably adopted, and oil is preferably adopted' needs to be explored.

Aiming at different industrial production devices, the catalyst needs to be made into different shapes and sizes to meet the requirements of industrial production. For the catalytic process of the continuous reforming moving bed for producing high-octane gasoline blending components and rich hydrogen and aromatic hydrocarbons, the aim is to realize Pt-Sn/gamma-Al₂O₃The continuous conveying of the catalyst meets other industrial design requirements, the mechanical abrasion of the catalyst is reduced, the carrier alumina is required to be made into round small balls with the diameter of 1.4-2.0 mm, and the crushing strength is not lower than 40N/particle. Because the supported Pt noble metal catalyst is adopted, higher requirements are placed on the impurity content in the catalyst.

The spherical alumina prepared by the alumina sol hot oil column forming method is firstly disclosed in patent US 2620314, the alumina sol is prepared by reacting aluminum with a hydrochloric acid solution, the alumina sol and a hexamethylenetetramine solution are mixed and then formed in a hot oil column device, and alumina spheres are obtained by pressure aging, water washing, drying, roasting and steam chambering treatment in an oil bath.

Chinese patent CN1089032C describes a preparation method of porous silicon-containing alumina carrier beads, which comprises steps of gelatinizing a mixed solution of aluminum chloride and sodium silicate with an ammonia water solution, filtering, washing with water, adding a nitric acid solution for peptization, and then performing oil ammonia column molding, drying and roasting. The prepared alumina pellets contain 5-15 mass% of silicon and have a specific surface area of 280-360 m²The specific pore volume of the composite material is 0.65-0.75 g/ml, the bulk density is 80-120N/grain, the pore volume is 0.6-0.8 ml/g, and pores with the pore diameter of 4-10 nm account for more than 90% of the total volume.

Chinese patent CN100431965C describes a spherical silicon-containing alumina and a preparation method thereof, which comprises adding silica sol into the alumina sol to obtain silicon-aluminum mixed sol, hot oil column forming, aging, washing, drying, and roasting to obtain the spherical silicon-containing alumina and SiO ₂1 to 15 mass%, a particle diameter of 0.005 to 5mm, and a specific surface area of 180 to 350m²The specific volume of the porous material is 0.3-0.6 g/ml, the pore volume is 0.7-1.5 ml/g, and pores with the diameter of 2-80 nm are larger than 70%. The method has the advantages of high forming temperature, long aging time, irritant gas generation in the forming process, high process cost and limitation on the application range.

Chinese patent CN104353503B describes a method for preparing a spherical silicon-aluminum composite carrier, which comprises adding silicon dioxide into aluminum gel, mixing uniformly, slowly adding alginate solution to make into suspension slurry, dropping polyvalent metal cation solution into water column to form spherical composite gel particles, taking out the gel particles, drying, and calcining to obtain the spherical silicon-aluminum composite carrier. Wherein the addition amount of the silicon dioxide is Al₂O₃The calculated mass of the aluminum cement is 0.1-3; the soluble alginate is one or more of sodium alginate, potassium alginate, magnesium alginate and ammonium alginate; the polyvalent metal cation solution is a salt solution of aluminum, zinc, calcium, copper, iron, ferrous iron, cobalt, manganese or nickel ions with the saturated concentration of 0.1 mol/L.

Chinese patent CN105478100A introduces a method for preparing silicon-containing gamma-Al₂O₃A preparation method of the pellet. By Al (OH)₃Preparing sol by the action of nitric acid, urea and sodium silicate, adding kerosene as pore-enlarging agent, forming in oil-ammonia column, filtering, drying and roasting to obtain silicon-containing gamma-Al₂O₃The pellets contained silicon in an amount of 0.30% by mass relative to dry alumina. It can be used as catalyst for preparing propylene by propane dehydrogenation, and its effect is better than that of alumina balls containing other elements.

However, the traditional preparation method of the silicon-containing alumina is a precipitation method or an impregnation method, uneven distribution is easily caused between silicon and alumina introduced into a system, and the impurity ion content is high, so that the physical and chemical properties of the silicon-containing alumina are influenced.

Disclosure of Invention

The invention aims to provide a reforming catalyst, a preparation method and application thereof.

In order to achieve the above object, the present invention provides a reforming catalyst comprising a SiO-containing catalyst₂The alumina pellet carrier and active components with the following contents based on alumina in the carrier:

0.01 to 2.4 mass% of platinum,

0.1 to 3.5 mass% of a group IVA metal,

0.1 to 2.4 mass% of halogen,

the SiO-containing layer₂The SiO in the alumina pellet carrier based on alumina₂The content is 0.01-3.5% by mass.

Preferably, the group IVA metal is tin and the SiO-containing metal₂The SiO in the alumina pellet carrier based on alumina₂The content is 0.01-2.4% by mass.

The invention also provides a preparation method of the provided catalyst, which comprises the following steps:

(1) will contain SiO₂Mixing the pseudo-boehmite powder, urea, IVA group metal compound and water to obtain a suspension, and acidizing the suspension by using acid liquor to obtain alumina sol;

(2) mixing the obtained alumina sol and hexamethylenetetramine solution, dripping the mixture into a hot oil column to form balls, taking out the formed balls, washing, drying and roasting to obtain the SiO-containing material₂The alumina pellet support of (a);

(3) and (3) introducing a platinum-containing compound and a halogen-containing compound into the alumina pellet carrier obtained in the step (2), and then sequentially drying, roasting and reducing to obtain the reforming catalyst.

The invention also provides a naphtha catalytic reforming method, which comprises the following steps: contacting naphtha raw material with the reforming catalyst provided by the invention and carrying out catalytic reforming reaction.

The reforming catalyst of the invention is introduced with silicon, which can improve the hydrothermal stability of the catalyst, and can obviously improve the liquefied gas (C) when being used in the catalytic reforming reaction of naphtha on the premise of maintaining higher conversion rate and liquid yield₃-C₄) The yield is reduced, and the carbon deposit of the catalyst is reduced.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a graph of the specific surface area of the reforming catalyst as a function of hydrothermal treatment time as provided in example 4 of the present invention and comparative example 1, where the abscissa is hydrothermal treatment time in h and the ordinate is specific surface area in m²·g^-1。

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The reforming catalyst provided by the invention comprises SiO-containing₂The alumina pellet carrier and active components of platinum, IVA group metal and halogen.

The reforming catalyst of the present invention is prepared by using a catalyst containing SiO₂Adding acid solution into the pseudo-boehmite powder, urea and IVA group metal compound as raw materials to prepare alumina sol, and then carrying out hot oil column forming, drying and roasting to prepare the SiO-containing alumina sol₂After which platinum and halogen are supported to produce a reforming catalyst. The reforming catalyst has good hydrothermal stability, can obviously improve the yield of liquefied gas on the premise of maintaining higher conversion rate and liquid yield when being used for naphtha reforming reaction, and simultaneously has low carbon deposition of the catalyst.

Preferably, in the catalyst of the present invention, the group IVA metal is tin, and the catalyst is prepared byContaining SiO₂The SiO in the alumina pellet carrier based on alumina₂The content is 0.01-2.4% by mass.

In the method of the present invention, the SiO-containing compound₂The pseudo-boehmite powder preferably comprises a first pseudo-boehmite powder and a second pseudo-boehmite powder, wherein the first pseudo-boehmite powder does not contain SiO₂The second pseudo-boehmite powder contains SiO₂SiO in the second pseudo-boehmite powder₂The content of (B) may be 10 to 50% by mass.

In the method of the invention, the pseudo-boehmite powder can be prepared by hydrolyzing alkoxy aluminum, preferably C₃-C₁₀The high-purity pseudo-boehmite prepared by hydrolyzing the alkoxy aluminum.

In step (1) of the process according to the invention, the solids content of the suspension, calculated as alumina, is from 15 to 30% by mass, preferably from 18 to 25% by mass.

In the method of the present invention, the amounts of the acids used for urea, hexamethylenetetramine and peptized pseudoboehmite are calculated based on the alumina contained in the alumina sol.

In the method, the urea and the hexamethylenetetramine are jointly used as the gelling agent, and ammonia gas can be generated after the urea and the hexamethylenetetramine are heated in a hot oil column, so that the solidification of the alumina pellets is promoted, and the strength of the alumina is improved. The mass ratio of urea to alumina used may be 30 to 110 mass%, preferably 50 to 90 mass%. The mass ratio of hexamethylenetetramine to alumina may be 3 to 18 mass%, preferably 3 to 10 mass%, and the concentration of hexamethylenetetramine in the hexamethylenetetramine solution may be 10 to 40 mass%.

In the method of the present invention, an acid solution is used for peptizing pseudo-boehmite and dispersing it to increase the cohesiveness of alumina pellets, the acid solution may contain an acid in a mass ratio of 0.5 to 18% by mass, preferably 2 to 12% by mass, to alumina, the acid solution may contain an acid in a concentration of 10 to 40% by mass, preferably 20 to 35% by mass, and the acid contained in the acid solution may be at least one selected from tartaric acid, lactic acid, citric acid, formic acid, acetic acid, nitric acid, hydrochloric acid and perchloric acid, preferably nitric acid.

Step (2) of the process of the present inventionIn the method, the alumina sol can be dripped into the oil phase of a hot oil column through a dripper to be condensed to form alumina globules, the oil phase in the hot oil column can be selected from at least one of kerosene, medical lubricating oil and liquid paraffin, preferably the liquid paraffin has a distillation range of 250-500 ℃ and is C₁₆-C₂₀Of (a) is a normal alkane. The temperature of the oil phase in the hot oil column can be 80-100 ℃, preferably 90-98 ℃, the thickness of the oil phase can be 80-500 cm, preferably 150-400 cm, the drying temperature can be 60-150 ℃, preferably 100-120 ℃, the drying time can be 0.5-24 hours, preferably 6-12 hours, the roasting temperature can be 400-850 ℃, preferably 500-750 ℃, and the roasting time can be 0.5-24 hours, preferably 2-8 hours.

One advantage of the preparation method of the invention is that: (2) in the step, the formed small balls (alumina wet balls) can be directly taken out from the bottom end of the hot oil column without aging treatment, thereby simplifying the preparation process of the small balls, saving the operation cost, and ensuring that the alumina small ball carrier has low impurity content and high crushing strength and hydrothermal stability.

The specific surface area of the alumina pellets prepared by the preparation method can be 140-350m²A/g of preferably 150-²The pore volume may be from 0.3 to 0.9mL/g, preferably from 0.4 to 0.8mL/g, and the particle size is preferably from 1.4 to 2.2 mm.

In the process of the invention, the group IVA metal is preferably tin and the compound of the group IVA metal may be selected from at least one of its halides, sulphates, oxalates, acetates and oxides, for example SnCl₂And/or SnCl₄(ii) a The platinum-containing compound can be selected from at least one of chloroplatinic acid, amine chloroplatinic acid, bromoplatinic acid, platinum trichloride, platinum tetrachloride hydrate, dichlorocarbonylplatinum dichloride, dinitrodiaminoplatinum and tetranitroplatinic acid, and is preferably chloroplatinic acid; the halogen is preferably chlorine, and the halogen-containing compound may be selected from at least one of hydrochloric acid, ammonium chloride and sodium chlorosilicate, and is preferably hydrochloric acid.

In the step (3) of the method, the drying temperature can be 50-300 ℃, preferably 50-150 ℃, and the time can be 2-48 hours, preferably 4-16 hours; the roasting temperature can be 370-900 ℃, preferably 500-750 ℃; the conditions for the reduction may include: the temperature is 250-650 ℃, preferably 400-600 ℃, the time is 0.5-16 hours, preferably 2-8 hours, the reducing gas is hydrogen and/or carbon monoxide, preferably hydrogen, which can be pure hydrogen, or a mixed gas of hydrogen and an inert gas, the inert gas is preferably nitrogen, argon or helium, and the content of hydrogen in the mixed gas can be 60-99 mass%, preferably 70-90 mass%.

In the present invention, the conditions of the catalytic reforming reaction may include: the temperature is 360-600 ℃, preferably 450-580 ℃, the pressure is 0.15-2.5MPa, preferably 0.15-1MPa, and the volume space velocity of the feeding (liquid) is 1-15h^-1Preferably 1-10h^-1The hydrogen/hydrocarbon volume ratio is 500-.

In the present invention, the naphtha feedstock may be selected from at least one of straight run naphtha, hydrocracked naphtha, coker naphtha, catalytically cracked naphtha and ethylene cracked naphtha. Naphtha feedstocks generally contain paraffins, naphthenes and aromatics, which may have a carbon number in the range of 5 to 12. The naphtha feedstock may have an initial boiling point of from 40 ℃ to 100 ℃, preferably from 70 ℃ to 90 ℃, and an end point of from 140 ℃ to 220 ℃, preferably from 160 ℃ to 180 ℃, as determined by ASTM D-86.

In the present invention, the water content of the naphtha feed as it enters the reforming reaction zone (vessel) should be less than 50ppm, preferably less than 20 ppm. The dehydration of the naphtha feed may be carried out by conventional adsorptive dehydration such as molecular sieves, alumina, or by suitable stripping operations in a fractionation unit, or by a combination of adsorptive drying and gas drying to remove water from the feed.

The catalyst of the invention is preferably used in a sulfur-free or low-sulfur environment, and the sulfur content of the naphtha feedstock is generally required to be not higher than 1.0 mug/g, preferably not higher than 0.5 mug/g. In order to achieve the desired sulfur content, the naphtha can be desulfurized by various desulfurization methods, including adsorption desulfurization and catalytic desulfurization.

The invention is further illustrated below by way of examples, without being limited thereto.

The viscosity of the alumina sol slurry in the examples was determined by: the alumina sol slurry prepared by adding the acid was stirred for 2 hours and the viscosity of the slurry was measured immediately. The method for measuring the slurry viscosity is a coating-4 cup method (GB1732), and the volume of a measuring cup is increased by 1 time to reach 100mL, which is different from the national standard method. When the device is operated, the flowing-out pipe orifice below the measuring cup is blocked by a finger, the slurry is poured into the cup until liquid flows out from the cup mouth, and the scraper is used for scraping along the cup mouth to scrape the redundant slurry at the cup mouth. And placing a beaker below the outlet of the cup opening, timing while removing the fingers, stopping timing when the last drop of the slurry flows out of the outlet pipe, and taking the recorded time as an index for judging the viscosity of the slurry.

The crushing strength of the alumina ball is measured by an ZQJ intelligent particle strength tester produced by a large-scale equipment diagnotor factory, the stress application speed is 5N/s, and the measuring range is 250N.

The hydrothermal stability test method of the alumina pellets comprises the following steps: placing the alumina pellets into a tubular furnace constant-temperature area, keeping the temperature at 650 ℃, introducing air with the water vapor content of 20 mass% for hydrothermal treatment, taking out samples at intervals, analyzing the specific surface area, plotting the obtained specific surface area against the treatment time, and judging the hydrothermal stability of the alumina pellets according to the change trend of the specific surface area of the alumina pellets along with time.

The specific surface, pore volume and pore distribution of the alumina pellets of the examples and comparative examples of the present invention were determined using static low temperature N₂The adsorption method was measured on an ASAP2400 instrument from Micromeritics, and the pore size distribution of the sample was calculated using the desorption branch. Elemental Si was measured using a plasma emission spectrometer on a Thermo iCAP6300 instrument from thermoelectricity corporation, USA. The amount of carbon deposited in the catalyst was measured by using an EMIA-820V infrared sulfur carbon measuring instrument manufactured by HORIBA, Japan.

Example 1

(1) Preparation of alumina Sol

Taking 68.6g of first pseudo-boehmite powder prepared by alkoxy aluminium hydrolysis method (Condea, Germany)Manufactured under the trademark SB with an alumina content of 72.8 mass%), 0.076g of a second pseudo-boehmite powder (manufactured by Condea, Germany, under the trademark SIRAL40HPV with an alumina content of 38.5 mass%, SiO₂Content 40 mass%), 40.0g of urea, 0.30g of SnCl₂·2H₂O and a proper amount of deionized water are stirred to form a suspension with the alumina content of 20 mass percent; the suspension was stirred for 0.5h, 5.0g of a 24% by mass nitric acid solution was added dropwise to the suspension for acidification, and the mixture was stirred at 20 ℃ for 2h to form an alumina sol having a viscosity of 21 s.

(2) Hot oil column forming

The oil phase of the hot oil column is liquid paraffin (provided by Beijing, Inc., chemical reagent of national drug group), the oil bath temperature is 95 ℃, and the thickness of the oil phase is 180 cm. Mixing alumina sol and 20g of 20 mass% hexamethylenetetramine solution, stirring for 0.5h, dropping into hot oil column to form balls, directly taking out the formed balls from the bottom end of the hot oil column, washing with water, drying at 110 deg.C for 2h, and calcining at 650 deg.C for 3h to obtain the final product containing SiO₂Alumina pellet support of (a), wherein SiO is based on alumina₂The content was 0.06 mass%, and the physical property parameters and crush strength thereof are shown in Table 1.

(3) Catalyst preparation

Adding 15mL of hydrochloric acid solution with the concentration of 100mg/mL and 70mL of deionized water into 17.5mL of chloroplatinic acid solution with the concentration of 8.3mg/mL, and then adding 50g of SiO-containing solution prepared in the step (2)₂The alumina pellet carrier is shaken and dipped for 1h and kept stand for 12 h. Filtering the filtrate, drying at 60 ℃ for 10h, roasting at 520 ℃ in air atmosphere at the gas/agent volume ratio of 500 for 6h, and reducing in 500 ℃ hydrogen for 6h to obtain the reduced catalyst. The reforming catalyst comprises the following components in percentage by weight based on alumina in a carrier: the platinum content was 0.30 mass%, the tin content was 0.32 mass%, and the chlorine content was 1.1 mass%.

(4) Reforming reaction

The catalyst prepared in this example was evaluated on a microreaction laboratory apparatus using n-heptane as the starting material under the following conditions: the inlet temperature of the reactor is 500 ℃, the reaction pressure is 0.7MPa, the volume ratio of hydrogen to hydrocarbon is 800, and the feeding space velocity is 2.0h^-1The catalyst loading was 1mL, the reaction time was 10 hours, the reaction results are shown in Table 2, and in Table 2, the liquid yield is C₅ ⁺(C5 and hydrocarbon with carbon number greater than 5) yield, and liquefied gas is C₃、C₄A hydrocarbon.

Example 2

67.8g of a first pseudo-boehmite powder (produced by Condea, Germany, having a brand SB of 72.8 mass% in alumina content) and 0.815g of a second pseudo-boehmite powder (produced by Condea, Germany, having a brand SIRAL40HPV of 38.5 mass% in alumina content and SiO 2)₂ Content 40 mass%), 40.0g of urea, 0.30g of SnCl₂·2H₂O and a proper amount of deionized water are stirred to form a suspension with the alumina content of 20 mass percent; the suspension was stirred for 0.5h, 5.4g of a 24% strength by mass nitric acid solution was added dropwise to the suspension for acidification, and the mixture was stirred at 20 ℃ for 2h to form an alumina sol having a viscosity of 22 s.

The pellets were shaped by heating the oil column in accordance with the method in step (2) of example 1, and the shaped pellets were taken out directly from the bottom of the hot oil column, washed with water, dried at 110 ℃ for 2 hours, and calcined at 650 ℃ for 3 hours to obtain SiO-containing pellets₂Alumina pellet support of (a), wherein SiO is based on alumina₂The content was 0.66 mass%, and the physical property parameters and crush strength thereof are shown in Table 1.

The catalyst was prepared by the methods of (3) and (4) in example 1 and the reforming reaction was carried out using n-heptane, and the reaction results are shown in Table 2. The reforming catalyst comprises the following components in percentage by weight based on alumina in a carrier: the platinum content was 0.30 mass%, the tin content was 0.32 mass%, and the chlorine content was 1.1 mass%.

Example 3

67.3g of a first pseudo-boehmite powder (produced by Condea, Germany, having a brand SB of 72.8 mass% in alumina content) and 1.31g of a second pseudo-boehmite powder (produced by Condea, Germany, having a brand SIRAL40HPV of 38.5 mass% in alumina content and SiO 2)₂ Content 40 mass%), 40.0g of urea, 0.30g of SnCl₂·2H₂O and a proper amount of deionized water are stirred to form a suspension with the alumina content of 20 mass percent; the suspension was stirred for 0.5h, and 5.0g of a 24% strength by mass nitric acid solution were added dropwiseAcidifying, and stirring at 20 deg.C for 2 hr to obtain alumina sol with viscosity of 20 s.

The pellets were shaped by heating the oil column in accordance with the method in step (2) of example 1, and the shaped pellets were taken out directly from the bottom of the hot oil column, washed with water, dried at 110 ℃ for 2 hours, and calcined at 650 ℃ for 3 hours to obtain SiO-containing pellets₂Alumina pellet support of (a), wherein SiO is based on alumina₂The content was 1.06% by mass, and the physical property parameters and crush strength thereof are shown in Table 1.

Example 4

66.5g of a first pseudo-boehmite powder (produced by Condea, Germany, having a brand SB of 72.8 mass% in alumina content) and 2.0g of a second pseudo-boehmite powder (produced by Condea, Germany, having a brand SIRAL40HPV of 38.5 mass% in alumina content and SiO 2₂ Content 40 mass%), 40.0g of urea, 0.30g of SnCl₂·2H₂O and a proper amount of deionized water are stirred to form a suspension with the alumina content of 20 mass percent; the suspension was stirred for 0.5h, and 4.8g of a 24 mass% nitric acid solution was added dropwise to acidify it, and stirred at 20 ℃ for 2h to form an alumina sol having a viscosity of 21 s.

The pellets were shaped by heating the oil column in accordance with the method in the step (1) and (2), and the shaped pellets were taken out directly from the bottom of the hot oil column, washed with water, dried at 110 ℃ for 2 hours, and calcined at 700 ℃ for 3 hours to obtain SiO-containing pellets₂Alumina pellet support of (a), wherein SiO is based on alumina₂The content was 1.63 mass%, and the physical property parameters and crush strength thereof are shown in Table 1.

The catalyst was prepared by the methods of (3) and (4) in example 1 and the reforming reaction was carried out using n-heptane as a raw material, the reaction results are shown in Table 2, and the specific surface area of the reforming catalyst provided as a function of the hydrothermal treatment time is shown in FIG. 1. The reforming catalyst comprises the following components in percentage by weight based on alumina in a carrier: the platinum content was 0.30 mass%, the tin content was 0.32 mass%, and the chlorine content was 1.1 mass%.

Example 5

65.9g of a first pseudo-boehmite powder (produced by Condea, Germany, having an alumina content of 72.8 mass%) and 2.6g of a second pseudo-boehmite powder (produced by Condea, Germany, having an alumina content of 38.5 mass%, SiO 40 HPV)₂ Content 40 mass%), 40.0g of urea, 0.30g of SnCl₂·2H₂O and a proper amount of deionized water are stirred to form a suspension with the alumina content of 20 mass percent; the suspension was stirred for 0.5h, and 4.6g of a 24 mass% nitric acid solution was added dropwise to acidify it, and stirred at 20 ℃ for 2h to form an alumina sol having a viscosity of 22 s.

The pellets were shaped by heating the oil column in accordance with the method in step (2) of example 1, and the shaped pellets were taken out directly from the bottom of the hot oil column, washed with water, dried at 110 ℃ for 2 hours, and calcined at 750 ℃ for 3 hours to obtain SiO-containing pellets₂Alumina pellet support of (a), wherein SiO is based on alumina₂The content was 2.12% by mass, and the physical property parameters and crush strength thereof are shown in Table 1.

Example 6

The catalyst prepared in example 4 was used, naphtha was used as the reaction raw material. A 100mL apparatus was charged with 50mL of catalyst, and the catalyst was evaluated using hydrotreated straight run naphtha as a feedstock, the properties of which are shown in table 3, under the evaluation conditions: the reaction temperature is 530 ℃, the reaction pressure is 0.7MPa, the volume ratio of hydrogen to hydrocarbon is 1000, and the hourly space velocity of the feed liquid is 1.8h^-1The reaction time was integrated for 120 hours, and the reaction results are shown in Table 2.

Comparative example 1

An alumina sol was prepared as in step (1) of example 1, except that the alumina sol was not incorporated with the second pseudo-boehmite powder containing silicon. Get68.7g of first pseudo-boehmite powder (manufactured by Condea, Germany, trade name SB, alumina content 72.8 mass%), 40.0g of urea, 0.30g of SnCl₂·2H₂O and a proper amount of deionized water are stirred to form a suspension with the alumina content of 20 mass percent, the suspension is stirred for 0.5h, 7.0g of nitric acid solution with the concentration of 24 mass percent is added drop by drop, the mixture is stirred for 2h at the temperature of 20 ℃ to form alumina sol slurry, and the viscosity of the alumina sol is 22 s.

The pellets were shaped by heating the oil column in the same manner as in the step (2) of example 1, and the shaped pellets were taken out directly from the bottom of the hot oil column, washed with water, dried at 110 ℃ for 2 hours, and calcined at 650 ℃ for 3 hours to obtain alumina pellet carriers, the physical property parameters and crushing strength of which are shown in Table 1.

The catalyst was prepared according to the methods of the steps (1), (3) and (4) and the reforming reaction was evaluated using n-heptane as a raw material, and the results are shown in Table 2, and the specific surface area of the reforming catalyst provided as a function of the hydrothermal treatment time is shown in FIG. 1. The reforming catalyst comprises the following components in percentage by weight based on alumina in a carrier: the platinum content was 0.30 mass%, the tin content was 0.32 mass%, and the chlorine content was 1.1 mass%.

Comparative example 2

The silica-free alumina pellets were prepared according to the method of comparative example 1, and were directly taken out from the bottom of the hot oil column to be pelletized, washed with water, dried at 110 ℃ for 2h, and calcined at 650 ℃ for 3h to obtain alumina pellets, and silica was introduced by late impregnation. Adding the obtained alumina pellets into an aqueous solution containing 2.8g of tetraethoxysilane (provided by Beijing Co., Ltd., a national group chemical reagent), modifying and modifying for 4h, performing rotary evaporation to dryness, and roasting at 650 ℃ for 3h to obtain the silicon modified alumina pellets, wherein the physical property parameters and the crushing strength of the silicon modified alumina pellets are shown in Table 1.

The catalysts were prepared in the same manner as in the step (3) and the step (4) of example 1, and the performance of the reforming reaction was evaluated using n-heptane as a raw material, and the results are shown in Table 2. The reforming catalyst comprises the following components in percentage by weight based on alumina in a carrier: the content of silicon oxide was 1.6 mass%, the content of platinum was 0.30 mass%, the content of tin was 0.32 mass%, and the content of chlorine was 1.1 mass%.

TABLE 1

Calculated on the basis of alumina

TABLE 2

TABLE 3

Claims

1. A reforming catalyst comprising SiO-containing₂The alumina pellet carrier and active components with the following contents based on alumina in the carrier:

0.01 to 2.4 mass% of platinum,

0.1 to 3.5 mass% of a group IVA metal,

0.1 to 2.4 mass% of halogen,

the SiO-containing layer₂The SiO in the alumina pellet carrier based on alumina₂The content is 0.01-3.5 mass%; the SiO-containing layer₂The alumina pellet carrier contains SiO₂The pseudo-boehmite powder, the urea and the IVA group metal compound are taken as raw materials, acid solution is added for acidification to prepare alumina sol, and then the alumina sol is prepared by hot oil column forming, drying and roasting.

2. The catalyst of claim 1, wherein the group IVA metal is tin and the SiO-containing metal₂The SiO in the alumina pellet carrier based on alumina₂The content is 0.01-2.4% by mass.

3. A method for preparing the catalyst of claim 1 or 2, comprising:

(1) will contain SiO₂Pseudo boehmite powder, urea and IVA group metal compoundMixing with water to obtain a suspension, and acidizing the suspension by using an acid solution to obtain alumina sol;

4. The production method according to claim 3, wherein the SiO-containing material is₂The pseudo-boehmite powder comprises a first pseudo-boehmite powder and a second pseudo-boehmite powder, wherein the first pseudo-boehmite powder does not contain SiO₂The second pseudo-boehmite powder contains SiO₂SiO in the second pseudo-boehmite powder₂The content of (B) is 10 to 50 mass%.

5. The method according to claim 3, wherein the pseudo boehmite powder is prepared by hydrolysis of an aluminum alkoxide.

6. The production process according to claim 3, wherein in the step (1), the suspension has a solid content of 15 to 30% by mass based on the alumina, urea is used in a mass ratio of 30 to 110% by mass to the alumina, an acid solution is used in a mass ratio of an acid contained in the acid solution to the alumina of 0.5 to 18% by mass, the acid solution has a concentration of 10 to 40% by mass, and the acid contained in the acid solution is at least one selected from the group consisting of tartaric acid, lactic acid, citric acid, formic acid, acetic acid, nitric acid, hydrochloric acid and perchloric acid.

7. The production method according to claim 3, wherein in the step (2), the mass ratio of hexamethylenetetramine to alumina is 3 to 18% by mass, and the concentration of hexamethylenetetramine in the hexamethylenetetramine solution is 10 to 40% by mass.

8. The preparation method according to claim 3, wherein in the step (2), the oil phase in the hot oil column is selected from at least one of kerosene, medical lubricant and liquid paraffin, the temperature of the oil phase in the hot oil column is 80-100 ℃, the thickness of the oil phase is 80-500 cm, the drying temperature is 60-150 ℃, and the roasting temperature is 400-850 ℃.

9. The process according to claim 3, wherein in the step (2), the formed pellet is taken out from the bottom of the hot oil column without aging treatment.

10. The production method according to claim 3, wherein the group IVA metal compound is at least one selected from a halide, a sulfate, an oxalate, an acetate and an oxide thereof;

the halogen-containing compound is at least one selected from hydrochloric acid, ammonium chloride and sodium chlorosilicate.

11. The method according to claim 3, wherein the group IVA metal compound is SnCl₂And/or SnCl₄The platinum-containing compound is at least one selected from chloroplatinic acid, amine chloroplatinic acid, bromoplatinic acid, platinum trichloride, platinum tetrachloride hydrate, dichlorocarbonylplatinum dichloride, dinitrodiaminoplatinum and tetranitroplatinic acid, and the halogen-containing compound is hydrochloric acid.

12. The preparation method according to claim 3, wherein in the step (3), the drying temperature is 50-300 ℃, and the roasting temperature is 370-900 ℃;

the reduction conditions include: the temperature is 250 ℃ and 650 ℃, the time is 0.5-16 hours, the reducing gas is hydrogen and/or carbon monoxide, and the water content in the reducing gas is less than 20 mu g/g.

13. A catalytic naphtha reforming process, the catalytic reforming process comprising: contacting a naphtha feedstock with a reforming catalyst according to claim 1 or 2 and carrying out a catalytic reforming reaction.

14. According to claimThe catalytic reforming method of claim 13, wherein the conditions of the catalytic reforming reaction include: the temperature is 360-600 ℃, the pressure is 0.15-2.5MPa, and the space velocity of the feeding volume is 1-15h^-1The hydrogen/hydrocarbon volume ratio is 500-;

the naphtha feedstock is selected from at least one of straight run naphtha, hydrocracked naphtha, coker naphtha, catalytically cracked naphtha and ethylene cracked naphtha.