Core-shell catalyst support, method for preparing the same, and use thereof

Abstract

The present application provides a core-shell catalyst carrier, comprising a spherical support body and an active component loading layer wrapped on the outer surface of the spherical support body, wherein the surface roughness Ra value of the catalyst carrier is 900 nm-1900 nm, and / or the surface roughness Rz value of the catalyst carrier is 5000 nm-10000 nm. The present application also provides a preparation method and application of the core-shell catalyst. In the core-shell catalyst of the present application, the active component loading layer on the outer surface is not easy to peel off from the support body, and the catalyst prepared by using the carrier is not easy to wear and peel off the platinum-based metal loading layer, thereby reducing the loss of platinum-based active components.

Description

Technical Field

[0001] This invention belongs to the field of catalysts, specifically relating to a core-shell catalyst support, its preparation method, and its application. Background Technology

[0002] In existing coated catalysts, the catalytically active components are distributed on the surface of the catalyst, exposed to the elements. During transport, loading, and use, friction between catalyst particles, collisions between the catalyst and equipment, and prolonged exposure to reactant gases inevitably cause the coating to peel off and wear down. This peeling and wear leads to the loss of active components, especially expensive platinum-based metals such as platinum, which not only affects catalyst performance but also results in resource and economic losses. Summary of the Invention

[0003] To address the problems of existing technologies, this invention provides a core-shell catalyst support with a certain surface roughness. It is composed of a support with specific roughness and an active component loading layer material with a specific particle size distribution. The active component loading layer on the outer surface is not easily peeled off from the support. Catalysts prepared using this support exhibit reduced wear and peeling of the platinum-based metal loading layer, minimizing the loss of platinum-based metal active components.

[0004] In a first aspect, the present invention provides a core-shell catalyst support, comprising a spherical support and an active component loading layer wrapped around the outer surface of the spherical support, wherein the surface roughness Ra of the catalyst support is 900 nm-1900 nm, and / or the surface roughness Rz of the catalyst support is 5000 nm-10000 nm.

[0005] In some embodiments, the surface roughness Ra value of the catalyst support is 900 nm, 1100 nm, 1300 nm, 1500 nm, 1700 nm, 1900 nm, or any value between them. In some preferred embodiments, the surface roughness Ra value of the catalyst support is 1400 nm to 1800 nm.

[0006] In some embodiments, the surface roughness Rz of the catalyst support is 5000 nm, 6000 nm, 7000 nm, 8000 nm, 9000 nm, 10000 nm, or any value between them. In some preferred embodiments, the surface roughness Rz of the catalyst support is 7000 nm to 9000 nm.

[0007] In some embodiments, the diameter of the catalyst support is 1-10 mm, for example, 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, or any value between them. In some preferred embodiments, the diameter of the catalyst support is 2 mm-5 mm.

[0008] In some embodiments, the spherical support is selected from at least one of α-alumina, silicon carbide, spinel, mullite, or cordierite.

[0009] In some embodiments, the active component loading layer is selected from at least one of γ-alumina, δ-alumina, θ-alumina, or molecular sieves. In some embodiments, the active component loading layer is γ-alumina.

[0010] In some embodiments, the weight ratio of the spherical support to the active component loading layer is (2-15):1, for example, 3:1, 5:1, 7:1, 9:1, 11:1, 13:1, 15:1, or any value between them. In some preferred embodiments, the weight ratio of the spherical support to the active component loading layer is (3-9):1.

[0011] In a second aspect, the present invention provides a method for preparing a core-shell catalyst support, comprising the following steps:

[0012] (a) Prepare a spherical support, wherein the surface roughness Ra value of the spherical support is 1900nm-2900nm and the Rz value is 10000nm-20000nm;

[0013] (b) Wrap the active component loading layer material onto the surface of the spherical support.

[0014] In some embodiments, step (a) of preparing the spherical support includes: forming spherical particles from powder of the support material, and then calcining the spherical particles.

[0015] In some embodiments, the calcination temperature is 800°C-1400°C, for example, 800°C, 900°C, 1000°C, 1100°C, 1200°C, 1300°C, 1400°C, or any value between them. In some preferred embodiments, the calcination temperature is 950°C-1300°C.

[0016] In some embodiments, the roasting time is 2h-24h, for example, 2h, 5h, 8h, 10h, 12h, 15h, 18h, 20h, 24h or any value between them. In some preferred embodiments, the roasting time is 4h-12h.

[0017] In some embodiments, the particle size of the support material is less than 100 mesh, preferably 300-400 mesh.

[0018] In some embodiments, the surface roughness Ra value of the spherical support is 1900 nm, 2100 nm, 2300 nm, 2500 nm, 2700 nm, 2900 nm, or any value between them. In some embodiments, the surface roughness Ra value of the spherical support is 2100 nm to 2500 nm.

[0019] In some embodiments, the surface roughness Rz of the spherical support is 10000 nm, 12000 nm, 14000 nm, 14500 nm, 16000 nm, 18000 nm, 20000 nm, or any value between them. In some preferred embodiments, the surface roughness Rz of the spherical support is 11000 nm to 16500 nm.

[0020] In some embodiments, in step (b), the spherical support is impregnated or atomized with a solution containing an active component load layer material to achieve the encapsulation.

[0021] In some embodiments, the solution containing the active component-supported layer material is obtained by wet ball milling.

[0022] In some embodiments, in the active component supported layer material, particles with a diameter of less than 2 μm account for less than 10%, particles with a diameter of 2-15 μm account for 75%-90%, and particles with a diameter of greater than 15 μm account for 5%-20%.

[0023] In a third aspect, the present invention provides a spherical catalyst comprising the catalyst support described in the first aspect or the catalyst support obtained by the preparation method described in the second aspect, and a platinum group metal supported on the catalyst support.

[0024] In some embodiments, the platinum group metal is selected from one or more of ruthenium, rhodium, osmium, platinum, and palladium, preferably platinum.

[0025] In some embodiments, the platinum group metal comprises 0.01% to 5.0% of the weight of the spherical catalyst, for example, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, or any value between therewith. In some preferred embodiments, the platinum group metal comprises 0.05% to 1.0% of the weight of the spherical catalyst.

[0026] In a fourth aspect, the present invention provides a method for preparing a spherical catalyst, comprising impregnating the catalyst support described in the first aspect or the catalyst support obtained by the preparation method described in the second aspect in an aqueous solution containing a platinum group metal element compound, and then drying and calcining it.

[0027] In some embodiments, the drying temperature is 60°C-200°C, for example 60°C, 100°C, 140°C, 180°C, 200°C or any value between them.

[0028] In some embodiments, the drying time is 2-24 hours, for example, 2 hours, 5 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 24 hours or any value between them.

[0029] In some embodiments, the calcination temperature is 400°C-800°C, for example, 400°C, 500°C, 600°C, 700°C, 800°C or any value between them.

[0030] In some embodiments, the roasting time is 2-12 hours, for example, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours or any value between them.

[0031] In a fifth aspect, the present invention provides a method for producing unsaturated hydrocarbons by dehydrogenation of saturated hydrocarbons, comprising subjecting hydrogen produced by the dehydrogenation of saturated hydrocarbons to a selective oxidation reaction in the presence of the catalyst described in the third aspect or the catalyst obtained by the preparation method of the fourth aspect.

[0032] In some embodiments, the conditions for the selective oxidation reaction include a reaction temperature of 520-650°C, a reaction pressure of 20-200 kPa, and a liquid hourly space velocity of 0.1-10 h⁻¹. -1 .

[0033] The core-shell catalyst support of this invention is composed of a support with a specific roughness and an active component loading layer material with a specific particle size distribution. The active component loading layer on the outer surface is not easily peeled off from the support. Catalysts prepared using this support are less prone to wear and peeling of the platinum-based metal loading layer, reducing the loss of platinum-based metal active components. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention in any way. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of this disclosure. Such structures and techniques have also been described in many publications.

[0035] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0036] The present invention will be described in detail below through embodiments.

[0037] In the method of this invention, surface roughness Ra and Rz are measured using a Mitutoyo SJ-411 surface roughness tester under the following conditions: test speed: 0.5 mm / s; recovery speed: 2.0 mm / s; probe 12AAC731. Evaluation conditions are as follows: standard: ISO 1997; curve type: R; filter: GAUSS; Λc: 0.25 mm; Λs: 2.5 μm; profile compensation: circle. Wherein, Ra represents the arithmetic mean of the absolute values ​​of profile offsets within the sampling length L, and Rz represents the sum of the average of the five largest profile peak heights and the average of the five largest profile valley depths within the sampling length.

[0038] In the method of this invention, the particle size distribution is tested using a Malvern MasterSizer2000, and water is used as a dispersant for wet testing.

[0039] The reagents used in the following examples are commercially available and of analytical grade.

[0040] Example 1

[0041] 1 kg of 300-mesh cordierite powder was extruded to form spherical particles with a diameter of 3 mm. After drying, the spherical particles were calcined at 1300℃ for 8 hours and then cooled to obtain a spherical support. The surface roughness of the spherical support was tested using a surface roughness tester, and Ra was 2400 nm and Rz was 13670 nm.

[0042] 20g of γ-alumina was added to water and wet-milled to obtain a γ-alumina suspension. The particle size distribution of the γ-alumina in the suspension was measured to be: particles smaller than 2μm accounted for 4.1%, particles with a diameter of 2-15μm accounted for 88.5%, and particles with a diameter greater than 15μm accounted for 7.4%. 80g of the above spherical support was taken, and the γ-alumina suspension was sprayed onto the spherical support by atomization coating. After drying and calcination, a shell-structured spherical catalyst support a1 was obtained. The surface roughness of support a1 was measured to be Ra = 1447nm and Rz = 7949nm.

[0043] Chloroplatinic acid was dissolved in water to prepare a solution with a platinum content of 25.0 mg / mL. 10 g of a shell-structured spherical catalyst support a was immersed in a chloroplatinic acid solution of equal volume, then dried at 120 °C for 4 hours, and then calcined at 600 °C for 6 hours to obtain a shell-structured spherical catalyst A1 with a platinum mass content of 0.20%.

[0044] The wear rate of the shell-structured spherical catalyst A1 was determined to be 0.18% according to the standard HG / T 2976-1999. The powder collected during the wear rate test was analyzed by elemental analysis, and the mass fraction of platinum in the powder was determined to be 0.97%. The loss rate of the active component platinum was 0.87%.

[0045] Example 2

[0046] 1 kg of 300-mesh cordierite powder was extruded to form spherical particles with a diameter of 3 mm. After drying, the spherical particles were calcined at 1100℃ for 8 hours and then cooled to obtain a spherical support. The surface roughness of the spherical support was tested using a surface roughness tester, and the Ra was 2483 nm and the Rz was 14473 nm.

[0047] Support a2 was prepared using the same method as in Example 1. The surface roughness of support a2 was measured, with Ra being 1762 nm and Rz being 8762 nm. The corresponding catalyst was prepared using the same method as in Example 1, yielding catalyst A2.

[0048] The wear rate of catalyst A2 was determined to be 0.14% according to the standard HG / T 2976-1999. The powder collected during the wear rate test was analyzed by elemental analysis, and the mass fraction of platinum in the powder was found to be 0.98%. The loss rate of the active component platinum was 0.69%.

[0049] Example 3

[0050] 1 kg of 300-mesh cordierite powder was extruded to form spherical particles with a diameter of 3 mm. After drying, the spherical particles were calcined at 950℃ for 8 hours and then cooled to obtain a spherical support. The surface roughness of the spherical support was tested using a surface roughness tester, and the Ra was 2461 nm and the Rz was 13763 nm.

[0051] Support a3 was prepared using the same method as in Example 1. The surface roughness of support a3 was measured, with Ra being 1512 nm and Rz being 8312 nm. The corresponding catalyst was prepared using the same method as in Example 1, yielding catalyst A3.

[0052] The wear rate of catalyst A3 was determined to be 0.17% according to the method in standard HG / T 2976-1999. The powder collected during the wear rate test was analyzed by elemental analysis, and the mass fraction of platinum in the powder was determined to be 0.96%. The loss rate of the active component platinum was 0.82%.

[0053] Example 4

[0054] 1 kg of 300-mesh cordierite powder was extruded to form spherical particles with a diameter of 3 mm. After drying, the spherical particles were calcined at 800℃ for 8 hours and then cooled to obtain a spherical support. The surface roughness of the spherical support was tested using a surface roughness tester, and Ra was 1955 nm and Rz was 11852 nm.

[0055] Support a4 was prepared using the same method as in Example 1. The surface roughness of support a4 was measured, with Ra being 1162 nm and Rz being 6374 nm. The corresponding catalyst was prepared using the same method as in Example 1, yielding catalyst A4.

[0056] The wear rate of catalyst A4 was determined to be 0.21% according to the method in standard HG / T 2976-1999. The powder collected during the wear rate test was analyzed by elemental analysis, and the mass fraction of platinum in the powder was determined to be 0.90%. The loss rate of the active component platinum was 0.95%.

[0057] Comparative Example 1

[0058] The spherical support was prepared using the same method as in Example 1.

[0059] 20g of γ-alumina was added to water and wet-milled to obtain a γ-alumina suspension. The particle size distribution of the suspension was as follows: particles smaller than 2μm accounted for 19.7%, particles with a diameter of 2-15μm accounted for 76.9%, and particles larger than 15μm accounted for 3.4%. 80g of the above spherical support was taken, and the γ-alumina suspension was sprayed onto the spherical support using atomized coating. After drying and calcination, a shell-structured spherical catalyst support a5 was obtained. The surface roughness of support a5 was measured: Ra = 844nm, Rz = 4603nm.

[0060] The corresponding catalyst was prepared using the same method as in Example 1, resulting in catalyst A5.

[0061] The wear rate of catalyst A5 was determined to be 0.18% according to the method in standard HG / T 2976-1999. The powder collected during the wear rate test was analyzed by elemental analysis, and the mass fraction of platinum in the powder was determined to be 0.96%. The loss rate of the active component platinum was 0.88%.

[0062] Comparative Example 2 prepared a spherical support using the same method as in Example 1.

[0063] 20g of γ-alumina was added to water and wet-milled to obtain a γ-alumina suspension. The particle size distribution of the γ-alumina in the suspension was measured to be: particles smaller than 2μm accounted for 8.3%, particles with a diameter of 2-15μm accounted for 73.2%, and particles with a diameter greater than 15μm accounted for 18.5%. 80g of the above spherical support was taken, and the γ-alumina suspension was sprayed onto the spherical support by atomization coating. After drying and calcination, a shell-structured spherical catalyst support a6 was obtained. The surface roughness of support a6 was measured to be Ra = 1975nm and Rz = 10281nm.

[0064] The corresponding catalyst was prepared using the same method as in Example 1, resulting in catalyst A6.

[0065] The wear rate of catalyst A6 was determined to be 0.44% according to the method in standard HG / T 2976-1999. The powder collected during the wear rate test was analyzed by elemental analysis, and the mass fraction of platinum in the powder was determined to be 0.83%. The loss rate of the active component platinum was 1.83%.

[0066] Comparative Example 3 prepared a spherical support using the same method as in Example 1.

[0067] 20g of γ-alumina was added to water and wet-milled to obtain a γ-alumina suspension. The particle size distribution of the γ-alumina in the suspension was measured to be: particles smaller than 2μm accounted for 1.6%, particles with a diameter of 2-15μm accounted for 44.4%, and particles with a diameter greater than 15μm accounted for 54.0%. 80g of the above spherical support was taken, and the γ-alumina suspension was sprayed onto the spherical support by atomization coating. After drying and calcination, a shell-structured spherical catalyst support a7 was obtained. The surface roughness of support a7 was measured to be Ra = 2803nm and Rz = 15753nm.

[0068] The corresponding catalyst was prepared using the same method as in Example 1, resulting in catalyst A7.

[0069] The wear rate of catalyst A7 was determined to be 0.75% according to the method in standard HG / T 2976-1999. The powder collected during the wear rate test was analyzed by elemental analysis, and the mass fraction of platinum in the powder was determined to be 0.78%. The loss rate of the active component platinum was 2.93%.

[0070] Comparative Example 4

[0071] 1 kg of 300-mesh cordierite powder was extruded to form spherical particles with a diameter of 3 mm. After drying, the spherical particles were calcined at 1600℃ for 8 hours and then cooled to obtain a spherical support. The surface roughness of the spherical support was tested using a surface roughness tester, and Ra was 1280 nm and Rz was 6893 nm.

[0072] Support a8 was prepared using the same method as in Example 1. The surface roughness of support a8 was measured, with Ra being 853 nm and Rz being 4566 nm. The corresponding catalyst was prepared using the same method as in Example 1, yielding catalyst A8.

[0073] The wear rate of catalyst A8 was determined to be 0.63% according to the method in standard HG / T 2976-1999. The powder collected during the wear rate test was analyzed by elemental analysis, and the mass fraction of platinum in the powder was determined to be 0.96%. The loss rate of the active component platinum was 3.02%.

[0074] Application examples

[0075] The catalysts prepared in Examples 1-4 and Comparative Examples 1-4 were used in the production of styrene by dehydrogenation of ethylbenzene, and the specific processes are shown below.

[0076] The hydrogen production process for the catalytic selective oxidation of saturated aromatic hydrocarbon ethylbenzene to unsaturated aromatic hydrocarbon styrene was carried out in a stainless steel reaction tube with a catalyst loading of 30 mL. The reactant composition consisted of styrene 2.4% (molar composition), ethylbenzene 5.4%, benzene and toluene 0.08%, hydrogen 2.4%, oxygen 1.1%, nitrogen 0.11%, and water 88.51%. The reaction temperature was 580 °C, the reaction pressure was 100 kPa, and the space velocity was 3 h⁻¹. -1 The results are shown in Table 1 below.

[0077] Table 1

[0078] A1 81.1 99.8 88.7 A2 82.7 99.9 91.5 A3 81.2 99.9 90.5 A4 81.0 99.8 89.4 A5 76.9 99.6 89.5 A6 80.2 99.5 86.6 A7 80.9 99.7 88.2 A8 80.8 99.8 88.5

[0079] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A core-shell catalyst support, comprising a spherical support and an active component loading layer wrapped around the outer surface of the spherical support, wherein, The surface roughness Ra value of the catalyst support is 900nm-1900nm, and / or the surface roughness Rz value of the catalyst support is 5000nm-10000nm; The surface roughness Ra of the spherical support is 1900nm-2900nm, and the Rz is 10000nm-20000nm. In the active component supported layer material, particles with a diameter of less than 2 μm account for less than 10%, particles with a diameter of 2-15 μm account for 75%-90%, and particles with a diameter of more than 15 μm account for 5%-20%. The spherical support is selected from at least one of α-alumina, silicon carbide, spinel, mullite or cordierite; The active component loading layer is selected from at least one of γ-alumina, δ-alumina, θ-alumina, or molecular sieve.

2. The catalyst support according to claim 1, characterized in that, The surface roughness Ra of the catalyst support is 1400nm-1800nm, and / or the surface roughness Rz of the catalyst support is 7000nm-9000nm.

3. The carrier according to claim 1 or 2, characterized in that, The diameter of the catalyst support is 1-10 mm.

4. The carrier according to claim 3, characterized in that, The diameter of the catalyst support is 2mm-5mm.

5. The catalyst support according to claim 1, characterized in that, The weight ratio of the spherical support to the active component loading layer is (2-15):1, by weight percentage.

6. The catalyst support according to claim 5, characterized in that, The active component support layer is γ-alumina.

7. The catalyst support according to claim 5, characterized in that, The weight ratio of the spherical support to the active component loading layer is (3-9):

1.

8. A method for preparing a core-shell catalyst support according to any one of claims 1-7, comprising the following steps: (a) Prepare a spherical support, wherein the surface roughness Ra value of the spherical support is 1900nm-2900nm and the Rz value is 10000nm-20000nm; (b) Wrap the active component loading layer material onto the surface of the spherical support.

9. The preparation method according to claim 8, characterized in that, In step (a), the preparation of the spherical support includes: forming the powder of the support material into spherical particles, and then calcining the spherical particles.

10. The preparation method according to claim 9, characterized in that, The roasting temperature is 800℃-1400℃.

11. The preparation method according to claim 10, characterized in that, The roasting temperature is 950℃-1300℃.

12. The preparation method according to claim 9, characterized in that, The roasting time is 2h-24h.

13. The preparation method according to claim 12, characterized in that, The roasting time is 4h-12h.

14. The preparation method according to claim 9, characterized in that, The spherical particles are prepared by rolling the support material into spheres, extruding, or centrifuging.

15. The preparation method according to claim 9, characterized in that, The particle size of the support material is less than 100 mesh.

16. The preparation method according to claim 15, characterized in that, The particle size of the support material is 300-400 mesh.

17. The method according to claim 9, characterized in that, The surface roughness Ra of the spherical support is 2100nm-2500nm, and Rz is 11000nm-16500nm.

18. The preparation method according to claim 8, characterized in that, In step (b), the spherical support is coated by dip-coating or atomizing with a solution containing the active component load layer material to achieve the encapsulation.

19. The preparation method according to claim 18, characterized in that, The solution containing the active component-supported layer material was obtained by wet ball milling.

20. A spherical catalyst comprising a catalyst support according to any one of claims 1-7 or a catalyst support obtained by the preparation method according to any one of claims 8-19, and a platinum group metal supported on the catalyst support.

21. The spherical catalyst according to claim 20, characterized in that, The platinum group metals are selected from one or more of ruthenium, rhodium, osmium, platinum, and palladium.

22. The spherical catalyst according to claim 21, characterized in that, The platinum group metal is platinum.

23. The spherical catalyst according to claim 20, characterized in that, The weight of the platinum group metal is 0.01%-5.0% of the weight of the spherical catalyst.

24. The spherical catalyst according to claim 23, characterized in that, The weight of platinum group metals is 0.05%-1.0% of the weight of the spherical catalyst.

25. A method for preparing a spherical catalyst, comprising impregnating the catalyst support of any one of claims 1-7 or the catalyst support obtained by the preparation method of any one of claims 8-19 in an aqueous solution containing a platinum group metal element compound, and then drying and calcining it.

26. The preparation method according to claim 25, characterized in that, The drying temperature is 60℃-200℃, and the time is 2-24h.

27. The preparation method according to claim 25, characterized in that, The roasting temperature is 400℃-800℃, and the time is 2-12h.

28. A method for dehydrogenating saturated hydrocarbons to produce unsaturated hydrocarbons, comprising subjecting hydrogen produced from the dehydrogenation of saturated hydrocarbons to a selective oxidation reaction in the presence of a catalyst according to any one of claims 20 to 24 or a catalyst prepared by any one of claims 25 to 27.

29. The method according to claim 28, wherein the conditions for the selective oxidation reaction include a reaction temperature of 520-650℃, a reaction pressure of 20-200 kPa, and a liquid hourly space velocity of 0.1-10 h⁻¹. -1 .