Support for propane dehydrogenation catalyst, catalyst and respective preparation methods

Abstract

The present invention provides a support for a propane dehydrogenation catalyst, a catalyst, and a preparation method thereof. The support comprises: an alumina matrix, the alumina matrix being formed by stacking alumina particles, the average particle size of the alumina particles being 5 to 30 nm; and a metal oxide component selected from at least one of oxides of Group IVB metals and oxides of Group VIII metals, and dispersed on the alumina matrix. The specific surface area of ​​the support is 100 to 210 m 2 / g; average pore diameter of 8.0-12.5nm; pore volume of 0.3-0.6mL / g; porosity of 20%-50%. The carrier provided by the present invention has unique structural characteristics and physical properties that can help increase the loading of subsequent active components and auxiliary components, thereby improving the activity of the catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a carrier and a catalyst for a propane dehydrogenation catalyst and respective preparation methods. Background Art

[0002] Propylene is an important basic chemical raw material, primarily used in the production of products such as polypropylene, acrylonitrile, propylene oxide, butanol, and cumene. However, propylene is primarily derived from a byproduct of steam cracking to produce ethylene. With the increasing demand for propylene products in the petrochemical industry, traditional propylene production processes are unable to meet market demand. New propylene synthesis technologies include the methanol-to-olefins (MTO) process, the methanol-to-propylene (MTP) process, and the propane dehydrogenation-to-propylene (PDH) process. Both the MTO and MTP processes use significant amounts of water during the production process, and the resulting wastewater, containing large amounts of organic matter, is difficult to treat and environmentally unfriendly. The propane dehydrogenation-to-PDH process, on the other hand, uses abundant and economical propane as a raw material to produce propylene. The reaction process does not require the introduction of water, significantly reducing wastewater production. This technology has become a key topic in the current petrochemical industry.

[0003] CN110614092A discloses a non-precious metal propane dehydrogenation catalyst, a preparation method thereof, a non-precious metal propane dehydrogenation catalyst prepared by the method, and a method for producing propylene by dehydrogenating propane. The method for producing the non-precious metal propane dehydrogenation catalyst comprises the following steps: (a) contacting an alumina material with an aqueous solution containing a sulfur source under ultrasonic conditions, followed by solvent removal, drying, and calcination to obtain a modified alumina support; and (b) impregnating the modified alumina support in a solution containing an active non-precious metal component precursor, followed by solvent removal, drying, and calcination. The non-precious metal propane dehydrogenation catalyst of the invention can achieve good catalytic activity in the propane dehydrogenation reaction to produce propylene.

[0004] CN107303508A discloses a modified alumina carrier, a preparation method thereof, a dehydrogenation catalyst, and its application. The preparation method comprises: subjecting the alumina carrier to a contact reaction with an aqueous inorganic acid solution, separating the reaction product, and then washing, drying, and calcining the separated solid product. The method of the present invention does not add other metal or non-metal elements to the carrier, thereby better maintaining the original chemical composition of the carrier and effectively avoiding changes in carrier performance caused by the introduction of other elements. Furthermore, the method can effectively improve the acidity and alkalinity of the alumina carrier surface, making it more conducive to the dispersion of active metal components, reducing the risk of carbon deposition, and improving the selectivity of the target product.

[0005] CN109569740A discloses an alumina carrier and its preparation method and application. The alumina carrier has a diameter of 0.5 to 3.5 mm and a specific surface area of ​​40 to 200 m 2 / g, the number of pores with a pore diameter of 15 to 50 nm accounts for no less than 90% of the total number of pores; the method for preparing an alumina carrier comprises the following steps: (1) preparing an alumina sol; (2) adding a pore-expanding agent and / or a gelling agent to the alumina sol to form a precursor, which is then heat-treated and molded; (3) drying the molded alumina at 100 to 150°C, then heating it to 950 to 1120°C at a heating rate of 1 to 5°C / min and keeping the temperature constant for 6 to 10 hours, and in the heating process, keeping the temperature constant for 1 to 10 hours in four temperature ranges of 200 to 300°C, 400 to 500°C, 600 to 700°C and 800 to 900°C, respectively, to obtain an alumina carrier. The alumina carrier prepared by the above method has a good and stable pore structure, concentrated pore distribution, uniform and controllable pore size, and has the characteristics of high specific surface area, large pore volume and high crushing strength.

[0006] CN111151232A discloses a method for preparing spherical alumina, comprising the following steps: (1) mixing raw materials containing an aluminum source, an acid I solution, and an acid II solution, and heating to obtain an aluminum sol; the acid II solution is an organic polyacid solution; (2) adding polyethylene glycol and a gelling agent to the aluminum sol to obtain a solution I; dripping the solution I into an oil column to form gel spheres, which are then aged, washed, dried, and calcined to obtain the spherical alumina. The spherical alumina prepared by this method has the characteristics of high strength, wear resistance, large pore size and pore volume, and the propane dehydrogenation catalyst prepared therefrom has strong carbon deposition resistance, good stability, and high propylene selectivity.

[0007] However, there is still much room for improvement in the catalysts and supports for propane dehydrogenation to propylene. Summary of the Invention

[0008] In view of the above-mentioned problems existing in the prior art, one of the objectives of the present invention is to provide a carrier for a propane dehydrogenation catalyst, whose unique structural characteristics and physical properties can help increase the loading of subsequent active components and auxiliary components, thereby improving the activity of the catalyst.

[0009] A second object of the present invention is to provide a method for preparing a carrier corresponding to the first object.

[0010] A third object of the present invention is to provide a propane dehydrogenation catalyst corresponding to the above object, which has high catalytic activity.

[0011] A fourth object of the present invention is to provide a method for preparing a catalyst corresponding to the above object.

[0012] A fifth object of the present invention is to provide an application of a catalyst corresponding to the above object.

[0013] To achieve one of the above purposes, the technical solution adopted by the present invention is as follows:

[0014] A carrier for a propane dehydrogenation catalyst, comprising:

[0015] an alumina matrix, wherein the alumina matrix is ​​formed by stacking alumina particles, and the average particle size of the alumina particles is 5 to 30 nm; and

[0016] a metal oxide component selected from at least one of oxides of Group IVB metals and oxides of Group VIII metals, and dispersed on the alumina matrix,

[0017] Wherein, the specific surface area of ​​the carrier is 100~210m 2 / g; average pore diameter is 8.0-12.5nm; pore volume is 0.3-0.6mL / g; porosity is 20%-50%.

[0018] In some preferred embodiments of the present invention, the equivalent diameter of the cross section of the carrier is defined as D, and the ratio of the metal oxide component within a distance of 1 / 4D from the center point to the metal oxide component within a distance of 1 / 4D to 1 / 2D from the center point is (0.9 to 1.1):1.

[0019] According to the present invention, the distribution of metal oxide components in the support can be analyzed by EDS. EDS analysis can utilize a Phoenix spectrometer manufactured by EDAX, performing line and surface scanning to obtain micro-area elemental composition and line and surface distribution. The measurable range includes elements B to U. During analysis, samples can be taken at 0.1 mm intervals.

[0020] According to the present invention, the carrier can be prepared into a cylinder with a diameter of 3 mm for elemental analysis. In this case, the test method can be to sample at intervals of 0.1 mm and analyze the distribution of the additive in the cylindrical catalyst with a diameter of 3 mm by EDS. With the center of the circle as 0, the proportion of the additive within a radius of 0.75 mm from the center to the additive within a radius of 0.75-1.5 mm from the center of the circle is set as r, and the measured result is that the range of r is (0.9-1.1):1. It is understandable that when the carrier of the present invention is prepared into other shapes, the above-mentioned proportion relationship is also satisfied.

[0021] In some preferred embodiments of the present invention, the metal oxide component is selected from at least one of titanium oxide, zirconium oxide, iron oxide, cobalt oxide and nickel oxide.

[0022] In some preferred embodiments of the present invention, the content of the alumina matrix is ​​95 wt % to 99.9 wt % based on the total weight of the carrier.

[0023] In some preferred embodiments of the present invention, the content of the metal oxide component is 0.1 wt% to 5 wt% based on the total weight of the alumina matrix.

[0024] In some preferred embodiments of the present invention, the content of the metal oxide component is 1 wt % to 5 wt % based on the total weight of the alumina matrix.

[0025] In some preferred embodiments of the present invention, the content of the oxide of the Group IVB metal is 0.5 wt % to 3 wt % based on the total weight of the alumina substrate.

[0026] In some preferred embodiments of the present invention, the content of the oxide of the Group VIII metal is 0.5 wt % to 2 wt % based on the total weight of the alumina substrate.

[0027] To achieve the second of the above objectives, the technical solutions adopted by the present invention are as follows:

[0028] A method for preparing the carrier according to any one of the above embodiments comprises:

[0029] S1. contacting an aluminum source with a solution containing an inorganic acid to form an acid-containing aluminum sol;

[0030] S2. contacting the acid-containing aluminum sol with a metal oxide source to form a support precursor;

[0031] S3. The carrier precursor is sequentially molded, dried and calcined to obtain the carrier.

[0032] In some preferred embodiments of the present invention, in step S1, the aluminum source is selected from at least one of pseudo-boehmite, boehmite, gibbsite, diaspore and boehmite.

[0033] In some preferred embodiments of the present invention, in step S1, the inorganic acid is selected from at least one of nitric acid, hydrochloric acid, sulfuric acid and phosphoric acid.

[0034] In some preferred embodiments of the present invention, in step S1, the mass concentration of the inorganic acid in the solution containing the inorganic acid is 15 wt% to 70 wt%. More preferably, the inorganic acid is nitric acid, and the mass concentration is 65 wt% to 68 wt%.

[0035] In some preferred embodiments of the present invention, in step S1, the mass ratio of the solution containing the inorganic acid to the aluminum source is (2-10):100.

[0036] In some preferred embodiments of the present invention, in step S1, the contacting conditions include: a temperature of 50°C to 80°C.

[0037] According to the present invention, in step S1, the contacting may be mixing, for example, adding an inorganic acid to the aluminum source.

[0038] In some preferred embodiments of the present invention, in step S2, the metal oxide source is selected from at least one of soluble salts of Group IVB metals and transition metals.

[0039] In some preferred embodiments of the present invention, in step S2, the metal oxide source is selected from at least one of a soluble salt of titanium, a soluble salt of zirconium, a soluble salt of iron, a soluble salt of cobalt, and a soluble salt of nickel.

[0040] According to the present invention, the soluble salts include hydrochlorides, sulfates, nitrates, phosphates, metasilicates, chlorides and the like.

[0041] In some preferred embodiments of the present invention, in step S2, the metal oxide source is selected from at least one of titanium tetrachloride, zirconium nitrate, ferric nitrate, ferric chloride, cobalt chloride and nickel chloride.

[0042] In some preferred embodiments of the present invention, in step S2, the mass ratio of the metal oxide source to the acid-containing aluminum sol is (0.1-5):100.

[0043] In some preferred embodiments of the present invention, in step S2, the contacting conditions include: a temperature of 25°C to 35°C.

[0044] According to the present invention, in step S2, the contacting may be mixing, for example, adding the metal oxide source into the acid-containing aluminum sol and kneading.

[0045] According to the present invention, in step S2, the metal oxide source may be first dissolved in water and then contacted with the acid-containing aluminum sol, wherein the amount of water used should not affect the subsequent molding process.

[0046] In some preferred embodiments of the present invention, in step S3, the drying conditions include: a temperature of 80° C. to 150° C., and a time of 1 to 8 hours.

[0047] In some preferred embodiments of the present invention, in step S3, the calcination conditions include: a temperature of 500° C. to 800° C. and a time of 2 to 10 hours.

[0048] According to the present invention, in step S3, the forming can be performed by conventional processes in the art.

[0049] To achieve the third of the above objectives, the technical solutions adopted by the present invention are as follows:

[0050] A propane dehydrogenation catalyst comprises: a carrier according to any one of the above embodiments or a carrier prepared according to the preparation method according to any one of the above embodiments, an active component and a promoter, wherein the active component comprises chromium or its oxide, and the promoter is selected from at least one of an alkali metal, an alkaline earth metal and their respective oxides.

[0051] In some preferred embodiments of the present invention, the auxiliary agent is selected from at least one of Li, Na, K, Cs, Mg and Ca and their respective oxides.

[0052] In some preferred embodiments of the present invention, the auxiliary agent is selected from at least one of Na, K, Mg and Ca and their respective oxides.

[0053] In some preferred embodiments of the present invention, the equivalent diameter of the cross section of the catalyst is defined as D, and the ratio of the active components within a distance of 1 / 3D from the center point to the active components within a distance of 1 / 3D to 1 / 2D from the center point is 1:(1.1 to 2.0), and the ratio of the auxiliary agent within a distance of 1 / 4D from the center point to the auxiliary agent within a distance of 1 / 4D to 1 / 2D from the center point is (0.9 to 1.1):1.

[0054] According to the present invention, the distribution of active components or additives can be determined through EDS analysis. EDS analysis can utilize a Phoenix spectrometer manufactured by EDAX, performing line and surface scanning to obtain micro-area elemental composition and line and surface distribution. The measurable range includes elements B to U. During analysis, samples can be taken at 0.1 mm intervals.

[0055] According to the present invention, the catalyst can be prepared into a cylinder with a diameter of 3 mm for elemental analysis. In this case, the test method can be to sample at intervals of 0.1 mm and analyze the distribution of active components or additives in the cylindrical catalyst with a diameter of 3 mm by EDS. With the center of the circle as 0, the active components within a radius of 1 mm from the center are set to the ratio of the active components within a radius of 1-1.5 mm relative to the center radius of the circle as r. The measurement result is that the r range distribution is 1:(1.1-2.0). The additives within a radius of 0.75 mm from the center are set to the ratio of the active components within a radius of 0.75-1.5 mm relative to the center radius of the circle as r. The measurement result is that the r range distribution is (0.9-1.1):1.

[0056] In some preferred embodiments of the present invention, the ratio of the active components within a distance of 1 / 3D from the center point to the active components within a distance of 1 / 3D to 1 / 2D from the center point is 1:(1.1 to 1.8).

[0057] It is understandable that when the catalyst of the present invention is prepared into other shapes, the above-mentioned proportion relationship is also satisfied.

[0058] In some preferred embodiments of the present invention, the content of each component in the catalyst is as follows, in parts by weight:

[0059] 10-30 parts of active ingredient;

[0060] 0.1 to 5 parts of additives;

[0061] 60 to 90 parts of carrier.

[0062] In some preferred embodiments of the present invention, the auxiliary agent includes an alkali metal or its oxide, and its content is 0.1 to 3 parts by weight.

[0063] In some preferred embodiments of the present invention, the auxiliary agent includes alkaline earth metal or its oxide, and its content is 0.1 to 2 parts by weight.

[0064] In some preferred embodiments of the present invention, the content of the active component is 10 wt% to 30 wt% relative to the total weight of the catalyst; the content of the auxiliary agent is 0.1 wt% to 5 wt%; and the content of the carrier is 60 wt% to 90 wt%.

[0065] In some preferred embodiments of the present invention, the auxiliary agent includes an alkali metal or an oxide thereof, and the content of the alkali metal or the oxide thereof is 0.1 wt% to 3 wt% relative to the total weight of the catalyst.

[0066] In some preferred embodiments of the present invention, the auxiliary agent includes alkaline earth metal or its oxide, and the content of the alkaline earth metal or its oxide is 0.1 wt% to 2 wt% based on the total weight of the catalyst.

[0067] To achieve the fourth objective above, the present invention adopts the following technical solutions:

[0068] A method for preparing the catalyst according to any one of the above embodiments comprises:

[0069] 1) vacuum impregnating the support with a solution containing an additive source, and then drying and calcining the support in sequence after vacuum impregnation to obtain a catalyst intermediate;

[0070] 2) impregnating the catalyst intermediate with an equal volume of a solution containing an active component source, and then drying and calcining the solution in sequence to obtain the catalyst.

[0071] In some preferred embodiments of the present invention, in step 1), the vacuum impregnation conditions include: vacuum degree of -50 to -100 kPa, temperature of 30° C. to 100° C., and time of 2 to 8 hours.

[0072] In some preferred embodiments of the present invention, in step 1), the calcination conditions include: a temperature of 550° C. to 850° C. and a time of 2 to 8 hours.

[0073] In some preferred embodiments of the present invention, in step 2), the conditions for the equal volume impregnation include: pressure: 95-105 kPa; temperature: 25° C.-35° C., and time: 2-24 h.

[0074] In some preferred embodiments of the present invention, in step 2), the calcination conditions include: a temperature of 500° C. to 850° C. and a time of 2 to 12 hours.

[0075] According to the present invention, the auxiliary agent source is selected from at least one of a soluble alkali metal salt and a soluble alkaline earth metal salt, preferably at least one of a soluble Li salt, a soluble Na salt, a soluble K salt, a soluble Cs salt, a soluble Mg salt and a soluble Ca salt, and more preferably at least one of sodium nitrate, sodium sulfate, sodium chloride, sodium acetate, potassium nitrate, potassium sulfate, potassium chloride, potassium acetate, cesium nitrate, cesium sulfate, cesium chloride, cesium acetate, magnesium nitrate, magnesium sulfate, magnesium chloride, magnesium acetate, calcium nitrate, calcium sulfate, calcium chloride and calcium acetate.

[0076] According to the present invention, the active component source is selected from soluble salts of active components, preferably chromium nitrate.

[0077] To achieve the fifth objective above, the present invention adopts the following technical solutions:

[0078] Use of the catalyst described in any one of the above embodiments or the catalyst prepared according to the preparation method described in any one of the above embodiments in the dehydrogenation of propane to propylene.

[0079] In some preferred embodiments of the present invention, the use comprises contacting a stream comprising propane with the catalyst.

[0080] In some preferred embodiments of the present invention, the contact conditions include: reaction temperature of 550-620°C, reaction pressure of 0.05-0.1 MPa, propane volume space velocity of 0.4-1.0 h -1 .

[0081] The beneficial effects of the present invention are at least in the following aspects:

[0082] First, the present invention uses inorganic acid to treat the aluminum source, which can cause the organic acid to react with part of the aluminum source and have a positive effect on the morphology of the carrier.

[0083] Secondly, the present invention can improve the dispersibility of the metal oxide source in the carrier by introducing the metal oxide source before the carrier is formed, and ultimately facilitate the loading of active components and additives, thereby affecting the activity of the catalyst.

[0084] Thirdly, the present invention uses a combination of vacuum impregnation and conventional equal volume impregnation to enable the additive to enter the pores of the carrier, while the active components are mainly distributed on the outer surface of the carrier, followed by the pores. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] Figure 1 is a scanning electron microscope photograph of the catalyst prepared in Example 1. DETAILED DESCRIPTION

[0086] The present invention is described in detail below by way of examples, but the protection scope of the present invention is not limited to the following description.

[0087] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are conventional products that can be obtained through commercial channels.

[0088] In the following embodiment, EDS was used to analyze a prepared cylindrical support sample with a diameter of 3 mm to determine the ratio, r1, of the metal oxide components within a radius of 0.75 mm from the center relative to the metal oxide components within a radius of 0.75-1.5 mm from the center of the circle. During the test, samples were taken at 0.1 mm intervals, with the center of the circle as zero.

[0089] In the following embodiment, EDS was used to analyze a 3 mm diameter cylindrical catalyst sample to determine the ratio of active components within a 1 mm radius relative to the radius of 1-1.5 mm from the center of the cylinder, r2, and the ratio of additives within a 1 mm radius relative to the radius of 1-1.5 mm from the center of the cylinder, r3. Samples were taken at 0.1 mm intervals, with the center of the cylinder as zero.

[0090] EDS analysis uses a Phoenix energy spectrometer produced by EDAX to perform line scanning and surface scanning on the elements to obtain the micro-area element composition and line distribution and surface distribution. The measurable range is: B to U elements.

[0091] In the following embodiment, the calculation formula for the conversion rate of propane is:

[0092]

[0093] In the following embodiment, the selectivity of propylene is calculated as:

[0094]

[0095] Example 1

[0096] (1) Weigh 300 g of diaspore, add 3% by weight of nitric acid solution (mass concentration is 68%), and then heat to 50° C. to obtain aluminum nitrate-containing sol.

[0097] (2) Weigh 10.45 g of zirconium nitrate pentahydrate, dissolve it in a small amount of water, add it to the cooled solid aluminum sol (25° C.) prepared in step (1), and knead until it becomes a dough.

[0098] (3) The above materials were extruded, dried (temperature 80°C for 6 hours), and calcined at high temperature (temperature 650°C for 4 hours) to obtain cylindrical modified alumina with a diameter of 3 mm and a length of 4 to 6 mm.

[0099] (4) 100 g of modified alumina and 27.4 g of a 10% sodium nitrate solution were weighed and vacuum impregnated at 60°C, -50 kPa, for 3 hours. After impregnation, the sample was dried (80°C for 6 hours) and calcined (650°C for 4 hours) to obtain Sample I.

[0100] (5) Weigh 105.3 g of chromium nitrate, prepare a solution in equal volumes, add it to sample I, and immerse at room temperature for 8 hours.

[0101] (6) The sample obtained in step (5) was placed in an oven at 100°C, excess water was quickly evaporated, and the sample was calcined in a muffle furnace at a calcination temperature of 650°C for 6 hours to obtain a dehydrogenation catalyst, which was marked as sample 1.

[0102] The average particle size of the alumina crystals in the carrier is 6nm; the specific surface area of ​​the carrier is 160.8m 2 / g, pore volume: 0.37cm 3 / g, average pore size: 9.2nm; r1 of the carrier is 1.01:1, r2 of the catalyst is 1:1.25, and r3 of the catalyst is 0.98:1.

[0103] The propane dehydrogenation reaction of Sample 1 was carried out using the following method, and the gas before and after the reaction was analyzed by gas chromatography for the content of various components. Specifically, pure propane gas was flowed through a mass flowmeter to enter the preheating zone for preheating, and then entered the reaction zone. Both the heating and reaction zones of the reactor were heated by electric heating wires to reach the predetermined temperature. The reactor consisted of a 600 mm long quartz tube with an inner diameter of 12 mm and an outer diameter of 20 mm. The post-reaction gas passed through a condenser and then entered a gas chromatograph for composition analysis.

[0104] The catalyst evaluation conditions in the isothermal fixed-bed reactor are as follows: 10 g of catalyst is loaded into the above isothermal fixed-bed reactor, the reaction pressure is atmospheric pressure, and the gas mass space velocity is 0.6 h -1 The reaction temperature was 600°C. Gases from the reaction for 10 minutes and 1 hour were analyzed by gas chromatography to determine the content of each component. The propane conversion and propylene selectivity were calculated. The catalyst evaluation results are shown in Table 1.

[0105] Example 2

[0106] (1) Weigh 300 g of diaspore, add 10% by weight of nitric acid solution (mass concentration is 68%), and then heat to 50° C. to obtain aluminum nitrate-containing sol.

[0107] (2) Weigh 10.45 g of zirconium nitrate pentahydrate, dissolve it in a small amount of water, add it to the cooled solid aluminum sol (25° C.) prepared in step (1), and knead until it becomes a dough.

[0108] (3) The above materials were extruded, dried (temperature 80°C for 6 hours), and calcined at high temperature (temperature 650°C for 4 hours) to obtain cylindrical modified alumina with a diameter of 3 mm and a length of 4 to 6 mm.

[0109] (4) 100 g of modified alumina and 27.4 g of a 10% sodium nitrate solution were weighed and vacuum impregnated at 60°C, -50 kPa, for 3 hours. After impregnation, the sample was dried (80°C for 6 hours) and calcined (650°C for 4 hours) to obtain Sample I.

[0110] (5) Weigh 105.3 g of chromium nitrate, prepare a solution in equal volumes, add it to sample I, and immerse at room temperature for 6 hours.

[0111] (6) The sample obtained in step (5) was placed in an oven at 100° C., excess water was quickly evaporated, and the sample was calcined in a muffle furnace at a temperature of 650° C. for 6 hours to obtain a dehydrogenation catalyst.

[0112] The average particle size of the alumina crystals in the carrier is 9 nm; the specific surface area of ​​the carrier is 136.2 m2 / g, pore volume: 0.37cm 3 / g, average pore size: 10.9nm; r1 of the carrier is 1.02:1, r2 of the catalyst is 1:1.11, and r3 of the catalyst is 1.0:1.

[0113] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0114] Example 3

[0115] (1) Weigh 300 g of pseudo-aluminum ore, add 3% by weight of hydrochloric acid solution (mass concentration is 68%), and then heat to 50° C. to obtain hydrochloric acid aluminum sol.

[0116] (2) Weigh 10.45 g of zirconium nitrate pentahydrate, dissolve it in a small amount of water, add it to the cooled solid aluminum sol (25° C.) prepared in step (1), and knead until it becomes a dough.

[0117] (3) The above materials were extruded, dried (temperature 100°C for 8 hours), and calcined at high temperature (temperature 650°C for 6 hours) to obtain cylindrical modified alumina with a diameter of 3 mm and a length of 4 to 6 mm.

[0118] (4) 100 g of modified alumina and 27.4 g of a 10% sodium nitrate solution were weighed and vacuum impregnated at 60°C, -50 kPa, for 3 hours. After impregnation, the sample was dried (80°C for 6 hours) and calcined (650°C for 4 hours) to obtain Sample I.

[0119] (5) Weigh 105.3 g of chromium nitrate, prepare a solution in equal volumes, add it to sample I, and immerse at room temperature for 10 hours.

[0120] (6) The sample obtained in step (5) was placed in an oven at 100° C., excess water was quickly evaporated, and the sample was calcined in a muffle furnace at a temperature of 650° C. for 6 hours to obtain a dehydrogenation catalyst.

[0121] The average particle size of the alumina crystals in the carrier is 21nm; the specific surface area of ​​the carrier is 161.5m 2 / g, pore volume: 0.36cm 3 / g, average pore size: 9.0nm; r1 of the carrier is 0.98:1, r2 of the catalyst is 1:1.67, and r3 of the catalyst is 1.01:1.

[0122] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0123] Example 4

[0124] (1) Weigh 300 g of pseudo-diatomite, add 2% by weight of nitric acid solution (mass concentration is 68%), and then heat to 80° C. to obtain aluminum nitrate-containing sol.

[0125] (2) 5.23 g of zirconium nitrate pentahydrate was dissolved in a small amount of water and added to the cooled solid aluminum sol (30° C.) obtained in step (1), and kneaded until it formed a dough.

[0126] (3) The above materials are extruded, dried (temperature 100°C time 4h), and high-temperature roasted (temperature 650°C time 6h) to obtain cylindrical modified alumina with a diameter of 3mm and a length of 4-6mm.

[0127] (4) 100 g of modified alumina and 21.5 g of a 10% potassium nitrate solution were weighed and vacuum impregnated at 80°C, -50 kPa, for 2 hours. After impregnation, the sample was dried (100°C for 4 hours) and calcined (650°C for 8 hours) to obtain Sample I.

[0128] (5) Weigh 105.3 g of chromium nitrate, prepare a solution in equal volumes, add it to sample I, and immerse at room temperature for 10 hours.

[0129] (6) The sample obtained in step (5) was placed in an oven at 120° C., excess water was quickly evaporated, and the sample was calcined in a muffle furnace at a calcination temperature of 650° C. for 4 hours to obtain a dehydrogenation catalyst.

[0130] The average particle size of the alumina crystals in the carrier is 15nm; the specific surface area of ​​the carrier is 192.3m 2 / g, pore volume: 0.48cm 3 / g, average pore size: 8.5nm; r1 of the carrier is 1.02:1, r2 of the catalyst is 1:1.25, and r3 of the catalyst is 0.99:1.

[0131] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0132] Example 5

[0133] (1) Weigh 300 g of pseudo-diatomite, add 5% by weight of nitric acid solution (mass concentration is 65%), and then heat to 80° C. to obtain aluminum nitrate-containing sol.

[0134] (2) Weigh 14.64 g of cobalt nitrate, dissolve it in a small amount of water, add it to the cooled solid aluminum sol (30° C.) prepared in step (1), and knead until it becomes a dough.

[0135] (3) The above materials were extruded, dried (temperature 100°C for 6 hours), and calcined at high temperature (temperature 650°C for 10 hours) to obtain cylindrical modified alumina with a diameter of 3 mm and a length of 4 to 6 mm.

[0136] (4) 100 g of modified alumina and 27.4 g of a 10% sodium nitrate solution were weighed and vacuum impregnated at 80°C, -100 kPa, for 2 hours. After impregnation, the sample was dried (100°C for 6 hours) and calcined (650°C for 4 hours) to obtain Sample I.

[0137] (5) Weigh 78.98 g of chromium nitrate, prepare a solution in equal volumes, add it to sample I, and immerse at room temperature for 10 hours.

[0138] (6) The sample obtained in step (5) was placed in an oven at 120° C., excess water was quickly evaporated, and the sample was calcined in a muffle furnace at a calcination temperature of 650° C. for 4 hours to obtain a dehydrogenation catalyst.

[0139] The average particle size of the alumina crystals in the carrier is 28nm; the specific surface area of ​​the carrier is 203.8m 2 / g, pore volume: 0.52cm 3 / g, average pore size: 8.1nm; r1 of the carrier is 1.0:1, r2 of the catalyst is 1:1.67, and r3 of the catalyst is 1.01:1.

[0140] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0141] Example 6

[0142] (1) Weigh 300 g of diaspore, add 3% by weight of nitric acid solution (mass concentration is 65%), and then heat to 70° C. to obtain aluminum nitrate-containing sol.

[0143] (2) Weigh 31.35 g of zirconium nitrate pentahydrate, dissolve it in a small amount of water, add it to the cooled solid aluminum sol (30° C.) prepared in step (1), and knead until it becomes a dough.

[0144] (3) The above materials are extruded, dried (temperature 100°C time 4h), and high-temperature roasted (temperature 650°C time 6h) to obtain cylindrical modified alumina with a diameter of 3mm and a length of 4-6mm.

[0145] (4) 100 g of modified alumina and 21.5 g of a 10% potassium nitrate solution were weighed and vacuum impregnated at 80°C, -50 kPa, for 2 hours. After impregnation, the sample was dried (100°C for 4 hours) and calcined (650°C for 8 hours) to obtain Sample I.

[0146] (5) Weigh 105.3 g of chromium nitrate, prepare a solution in equal volumes, add it to sample I, and immerse at room temperature for 6 hours.

[0147] (6) The sample obtained in step (5) was placed in an oven at 120° C., excess water was quickly evaporated, and the sample was calcined in a muffle furnace at a calcination temperature of 650° C. for 4 hours to obtain a dehydrogenation catalyst.

[0148] The average particle size of the alumina crystals in the carrier is 8nm; the specific surface area of ​​the carrier is 179.6m 2 / g, pore volume: 0.49cm 3 / g, average pore size: 9.2nm; r1 of the carrier is 0.97:1, r2 of the catalyst is 1:1.43, and r3 of the catalyst is 1.02:1.

[0149] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0150] Example 7

[0151] (1) Weigh 300 g of diaspore, add 3% by weight of nitric acid solution (mass concentration is 65%), and then heat to 80° C. to obtain aluminum nitrate-containing sol.

[0152] (2) Weigh 10.45 g of zirconium nitrate pentahydrate, dissolve it in a small amount of water, add it to the cooled solid aluminum sol (30° C.) prepared in step (1), and knead until it becomes a dough.

[0153] (3) The above materials were extruded, dried (temperature 100°C for 6 hours), and calcined at high temperature (temperature 650°C for 10 hours) to obtain cylindrical modified alumina with a diameter of 3 mm and a length of 4 to 6 mm.

[0154] (4) 100 g of modified alumina and 27.4 g of a 10% sodium nitrate solution were weighed and vacuum impregnated at 80°C, -60 kPa, for 6 hours. After impregnation, the sample was dried (100°C for 6 hours) and calcined (650°C for 4 hours) to obtain Sample I.

[0155] (5) Weigh 52.65 g of chromium nitrate, prepare a solution in equal volumes, add it to sample I, and immerse at room temperature for 10 hours.

[0156] (6) The sample obtained in step (5) was placed in an oven at 120° C., excess water was quickly evaporated, and the sample was calcined in a muffle furnace at a calcination temperature of 650° C. for 4 hours to obtain a dehydrogenation catalyst.

[0157] The average particle size of the alumina crystals in the carrier is 11nm; the specific surface area of ​​the carrier is 108.7m 2 / g, pore volume: 0.42cm 3 / g, average pore size: 11.9nm; r1 of the carrier is 1.01:1, r2 of the catalyst is 1:1.25, and r3 of the catalyst is 1.01:1.

[0158] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0159] Example 8

[0160] (1) Weigh 300 g of pseudo-diatomite, add 5% by weight of nitric acid solution (mass concentration is 65%), and then heat to 80° C. to obtain aluminum nitrate-containing sol.

[0161] (2) Weigh 10.45 g of zirconium nitrate pentahydrate, dissolve it in a small amount of water, add it to the cooled solid aluminum sol (30° C.) prepared in step (1), and knead until it becomes a dough.

[0162] (3) The above materials were extruded, dried (temperature 100°C for 6 hours), and calcined at high temperature (temperature 650°C for 10 hours) to obtain cylindrical modified alumina with a diameter of 3 mm and a length of 4 to 6 mm.

[0163] (4) 100 g of modified alumina and 27.4 g of a 10% sodium nitrate solution were weighed and vacuum impregnated at 80°C, -80 kPa, for 4 hours. After impregnation, the sample was dried (100°C for 4 hours) and calcined (650°C for 6 hours) to obtain Sample I.

[0164] (5) Weigh 157.95 g of chromium nitrate, prepare a solution in equal volumes, add it to sample I, and immerse at room temperature for 4 hours.

[0165] (6) The sample obtained in step (5) was placed in an oven at 120° C., excess water was quickly evaporated, and the sample was calcined in a muffle furnace at a calcination temperature of 650° C. for 8 hours to obtain a dehydrogenation catalyst.

[0166] The average particle size of the alumina crystals in the carrier is 16nm; the specific surface area of ​​the carrier is 167.7m 2 / g, pore volume: 0.41cm 3 / g, average pore size: 9.5nm; r1 of the carrier is 0.97:1, r2 of the catalyst is 1:1.11, and r3 of the catalyst is 1.01:1.

[0167] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0168] Comparative Example 1

[0169] (1) 300 g of pseudo-diamond stone was weighed, and a 3% by weight aqueous solution thereof was added, followed by heating to 50° C. to obtain a mixture containing aluminum nitrate.

[0170] (2) Weigh 10.45 g of zirconium nitrate pentahydrate, dissolve it in a small amount of water, add it to the cooled mixture (25° C.) obtained in step (1), and knead until it becomes a dough.

[0171] (3) The above materials were extruded, dried (temperature 80°C for 6 hours), and calcined at high temperature (temperature 650°C for 4 hours) to obtain cylindrical modified alumina with a diameter of 3 mm and a length of 4 to 6 mm.

[0172] (4) 100 g of modified alumina and 27.4 g of a 10% sodium nitrate solution were weighed and vacuum impregnated at 60°C, -50 kPa, for 3 hours. After impregnation, the sample was dried (80°C for 6 hours) and calcined (650°C for 4 hours) to obtain Sample I.

[0173] (5) Weigh 105.3 g of chromium nitrate, prepare a solution in equal volumes, add it to sample I, and immerse at room temperature for 8 hours.

[0174] (6) The sample obtained in step (5) was placed in an oven at 100° C., excess water was quickly evaporated, and the sample was calcined in a muffle furnace at a temperature of 650° C. for 6 hours to obtain a dehydrogenation catalyst.

[0175] The catalyst prepared was tested in the same manner as in Example 1. The results are shown in Table 1.

[0176] Comparative Example 2

[0177] (1) Weigh 300 g of tantalum, add 3% by weight of nitric acid solution (mass concentration 68%), and heat to 50°C to obtain aluminum nitrate sol. When the aluminum nitrate sol cools to about 25°C, add a small amount of water and knead until it forms a dough.

[0178] (2) The above materials are extruded into strips, dried (temperature 80°C for 6 hours), and calcined at high temperature (temperature 650°C for 4 hours) to obtain cylindrical alumina with a diameter of 3 mm and a length of 4 to 6 mm.

[0179] (3) Weigh 10.45 g of zirconium nitrate pentahydrate, prepare a solution in equal volumes, add it to the alumina prepared in step (2), and impregnate at room temperature for 8 hours. After impregnation, dry it (temperature 80°C for 6 hours) and calcine it at high temperature (temperature 650°C for 4 hours) to obtain Sample I.

[0180] (4) 100 g of Sample I and 27.4 g of a 10% sodium nitrate solution were weighed and vacuum impregnated at 60°C, -50 kPa, for 3 hours. After impregnation, the sample was dried (80°C for 6 hours) and calcined (650°C for 4 hours) to obtain Sample II.

[0181] (5) Weigh 105.3 g of chromium nitrate, prepare a solution in equal volumes, add it to sample II, and immerse at room temperature for 8 hours.

[0182] (6) The sample obtained in step (5) was placed in an oven at 100° C., excess water was quickly evaporated, and the sample was calcined in a muffle furnace at a temperature of 650° C. for 6 hours to obtain dehydrogenation catalyst I.

[0183] The catalyst prepared was tested in the same manner as in Example 1. The results are shown in Table 1.

[0184] Comparative Example 3

[0185] This comparative example used the alumina support prepared in Example 1 as the support and was essentially carried out in the same manner as in Example 1, differing only in that the auxiliary agent, sodium nitrate, was also introduced via an equal volume impregnation method. The resulting catalyst was tested in the same manner as in Example 1. The results are shown in Table 1.

[0186] Comparative Example 4

[0187] This comparative example used the alumina support prepared in Example 1 as the support and was carried out essentially in the same manner as in Example 1, differing only in that the active component was also introduced via vacuum impregnation. The resulting catalyst was tested in the same manner as in Example 1. The results are shown in Table 1.

[0188] Table 1

[0189]

[0190]

[0191] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A propane dehydrogenation catalyst comprising a support, an active component and a promoter, wherein the active component comprises chromium or its oxide, and the promoter is selected from at least one of an alkali metal, an alkaline earth metal and their oxides; The carrier comprises: An alumina matrix, wherein the alumina matrix is ​​formed by stacking alumina particles, and the average particle size of the alumina particles is 5 to 30 nm; as well as a metal oxide component selected from at least one of oxides of Group IVB metals and oxides of Group VIII metals, and dispersed on the alumina matrix, Wherein, the specific surface area of ​​the carrier is 100~210m 2 / g; average pore diameter is 8.0-12.5nm; pore volume is 0.3-0.6mL / g; porosity is 20%-50%; The equivalent diameter of the cross section of the carrier is defined as D, and the ratio of the metal oxide component within a distance of 1 / 4D from the center point to the metal oxide component within a distance of 1 / 4D to 1 / 2D from the center point is (0.9-1.1):1; The equivalent diameter of the cross section of the catalyst is defined as D. The ratio of the active component within a distance of 1 / 3D from the center point to the active component within a distance of 1 / 3D to 1 / 2D from the center point is 1:(1.1-2.0). The ratio of the additive within a distance of 1 / 4D from the center point to the additive within a distance of 1 / 4D to 1 / 2D from the center point is (0.9-1.1):

1. The content of each component in the catalyst is as follows in parts by weight: 10-30 parts of active ingredient; 0.1 to 5 parts of additives; 60 to 90 parts of carrier.

2. The catalyst according to claim 1, characterized in that The metal oxide component is selected from at least one of titanium oxide, zirconium oxide, iron oxide, cobalt oxide and nickel oxide, and / or Based on the total weight of the carrier, the content of the alumina matrix is ​​95wt% to 99.9wt%; and / or based on the total weight of the alumina matrix, the content of the metal oxide component is 0.1wt% to 5wt%.

3. The catalyst according to claim 1 or 2, characterized in that The preparation method of the carrier comprises: S1. contacting an aluminum source with a solution containing an inorganic acid to form an acid-containing aluminum sol; S2. contacting the acid-containing aluminum sol with a metal oxide source to form a support precursor; S3. The carrier precursor is sequentially molded, dried and calcined to obtain the carrier.

4. The catalyst according to claim 3, characterized in that In step S1, The aluminum source is selected from at least one of pseudo-boehmite, boehmite, gibbsite, diaspore and boehmite; the inorganic acid is selected from at least one of nitric acid, hydrochloric acid, sulfuric acid and phosphoric acid; and / or The inorganic acid solution has a mass concentration of 15 wt% to 70 wt%; and / or The mass ratio of the solution containing the inorganic acid to the aluminum source is (2-10):100; and / or The contact conditions include: a temperature of 50°C to 80°C.

5. The catalyst according to claim 4, characterized in that The inorganic acid is nitric acid, and its mass concentration is 65 wt% to 68 wt%.

6. The catalyst according to claim 3, characterized in that In step S2, The mass ratio of the metal oxide source to the acid-containing aluminum sol is (0.1-5):100; and / or The contact conditions include: a temperature of 25°C to 35°C.

7. The catalyst according to claim 3, characterized in that In step S3, The drying conditions include: a temperature of 80°C to 150°C and a time of 1 to 8 hours; and / or The calcination conditions include: a temperature of 500° C. to 800° C. and a time of 2 to 10 hours.

8. The catalyst according to claim 3, characterized in that The auxiliary agent is selected from at least one of Li, Na, K, Cs, Mg and Ca and their respective oxides.

9. A method for preparing the catalyst according to any one of claims 1 to 8, comprising: 1) vacuum impregnating the support with a solution containing an additive source, and then drying and calcining the support in sequence after vacuum impregnation to obtain a catalyst intermediate; 2) impregnating the catalyst intermediate with an equal volume of a solution containing an active component source, and then drying and calcining the solution in sequence to obtain the catalyst.

10. The preparation method according to claim 9, characterized in that In step 1), the vacuum impregnation conditions include: vacuum degree of -50 to -100 kPa, temperature of 30°C to 100°C, and time of 2 to 8 hours; the calcination conditions include: temperature of 550°C to 850°C, and time of 2 to 8 hours; and / or In step 2), the conditions for the equal volume impregnation include: pressure: 95-105 kPa; temperature: 25° C.-35° C., and time: 2-24 h; and the conditions for the calcination include: temperature: 500° C.-850° C., and time: 2-12 h.

11. Use of the catalyst according to any one of claims 1 to 8 or the catalyst prepared by the preparation method according to claim 9 or 10 in the dehydrogenation of propane to propylene.

12. The use according to claim 11, characterized in that A stream containing propane is contacted with the catalyst.

13. The use according to claim 12, characterized in that The contact conditions include: reaction temperature of 550-620°C, reaction pressure of 0.05-0.1 MPa, propane volume space velocity of 0.4-1.0 h -1 .

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