Catalytically active products and methods for producing such catalytically active products

Abstract

A method for producing a catalytically active product (10) is disclosed. The method includes the steps of providing a substrate (11) and depositing a first material (12) and particles (13) of a second material on the substrate, the particles (13) of the second material having a higher melting point than the first material (12). The substrate (11) with the first material (12) and said particles (13) is then heated to a temperature that melts the first material (12) and does not melt the particles (13) of the second material, and the first material (12) and particles (13) are bonded to the substrate (11). The particles (13) are partially embedded in the first material (12) and form a roughened surface. A ceramic material is deposited on the roughened surface formed by the particles (13) to form a ceramic layer (14) thereon, and a catalytically active material (16) is added to the ceramic layer (14). A catalytically active product is also disclosed.

Description

[Technical Field]

[0001] The present invention relates to catalytically active products and methods for their production. Catalytically active products are used in various chemical reactions, including combustion, refining, catalytic reforming, etc. For example, catalytically active products are used in the purification of flue gases for carbon monoxide and / or hydrocarbons such as VOCs and PAHs. Such catalytically active products can be used in reactors for various types of chemical reactions. Catalytically active products of this type can also be used in burners for the combustion of gaseous fuels such as natural gas, propane, butylene, or similar gases. [Background technology]

[0002] Over the past few years, there has been increasing interest in developing environmentally friendly processes related to the purification of exhaust and flue gas emissions. A variety of catalytic devices have been presented over the years, all with the same goal of achieving effective purification of pollutants that are harmful to both human health and the environment.

[0003] Patent document 1 describes a catalyst and a method for producing the same, in which a layer of a porous ceramic layer is formed on a mesh substrate by thermal spraying, the surface area of ​​the ceramic layer is subsequently increased, and then the ceramic layer with increased surface area is impregnated with a catalytically active material. Although the purification results and production method of this known catalyst are sufficient for many applications, there is room for improvement both in the method for producing the catalytically active product and in the catalytically active product itself.

[0004] One problem with prior art methods for producing catalytically active products is that they are complex and require expensive equipment.

[0005] Another problem with such prior art methods is that they consume a significant amount of energy. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 97 / 02092 Summary of the Invention [Problem to be solved by the invention]

[0007] It is an object of the present invention to overcome or at least mitigate one or more of the problems discussed above in connection with the prior art and to provide an efficient method for producing catalytically active products, and also to provide such products which allow for easy production. [Means for solving the problem]

[0008] The present invention relates to a method for producing a catalytically active product, said method comprising the steps of: a) providing a substrate; b) depositing particles of a first material and a second material onto the substrate, the particles of the second material having a higher melting point than the first material; c) heating the substrate with the first material and the particles to a temperature that melts the first material but does not melt the particles of the second material, thereby adhering the first material and the particles to the substrate, the particles being partially embedded in the first material and forming a roughened surface; d) depositing a ceramic material onto the roughened surface formed by the particles to form a ceramic layer thereon; e) adding catalytically active material to said ceramic layer; Includes.

[0009] The method according to the invention allows for the easy and efficient production of catalytically active products. The invention allows for the production of catalytically active products without a thermal spraying process. The combination of the first material and the particles allows for a safe, reliable and efficient fixation of the ceramic layer to the substrate to produce the catalytically active product.

[0010] The method can include providing particles of the first material and / or the second material as one or more suspensions, optionally combining both materials and providing them as a suspension. Thus, the first material and / or the second material can be deposited on the substrate in an efficient manner, such as by spraying or other coating processes, and the suspensions can be deposited at any suitable temperature, such as room temperature. Thus, the first material can be deposited on the substrate without first melting it. The method can then include heating the substrate having the particles of the first material and the second material thereon in a furnace, such as a vacuum furnace, or using a reducing or inert gas, to melt only the first material and bond it to the substrate while fixing the particles to the first material. Thus, the first material and the particles can be produced in an efficient and reliable manner, efficiently forming an attachment layer for subsequent fixing of the ceramic layer.

[0011] After fixing the first material to the substrate by melting it, the method can include depositing a ceramic layer by providing a ceramic material as a suspension and depositing the suspension, for example by spraying, onto the first material containing the particles, so that the ceramic material is formed in an easy manner and partially surrounds the particles protruding from the first material, and mechanically securely fixes the ceramic layer to the substrate, for example by drying and firing.

[0012] The present invention also relates to a catalytically active product comprising a substrate, a first material, particles of a second material having a higher melting point than the first material, and a ceramic layer adhered to the substrate via the first material and particles of the second material partially embedded in the first material and protruding into the ceramic layer, the ceramic layer being formed with a pore structure comprising the catalytically active material.

[0013] The substrate can comprise a metal such as steel, aluminum, copper, or other suitable metal. The substrate can be formed as a sheet, a mesh such as wire mesh, or a perforated plate, and can optionally be formed into any suitable shape, including a cylindrical shape. The first material can comprise a metal such as a low-melting-point metal or alloy. The first material can have a lower melting point than the substrate and the particles of the second material. The particles of the second material can comprise a metal powder, a ceramic powder, or a composite or mixture thereof. The particles of the second material can have a particle size of 20 to 50 μm to provide efficient anchoring to the first material and ceramic layer. By providing coarse, high-melting-point particles in the low-melting-point first material layer, a larger surface area is created, improving adhesion of the ceramic layer to the substrate surface. Thus, the particles provide a means for enhancing adhesion of the ceramic layer to the substrate.

[0014] Further features and advantages of the invention will become apparent from the following description of embodiments, the accompanying drawings and the dependent claims. [Brief explanation of the drawings]

[0015] By way of example, embodiments of the invention will now be described with reference to the accompanying drawings, in which:

[0016] [Figure 1] 1 is a schematic cross-sectional view of a catalytically active product according to the present invention. [Figure 2] 2 is a series of schematic cross-sectional views of a method for producing the catalytically active product of FIG. 1 according to a first embodiment. [Figure 3] 2 is a series of schematic cross-sectional views of a method for producing the catalytically active product of FIG. 1 according to a first embodiment. [Figure 4] 2 is a series of schematic cross-sectional views of a method for producing the catalytically active product of FIG. 1 according to a first embodiment. [Figure 5] 2 is a series of schematic cross-sectional views of a method for producing the catalytically active product of FIG. 1 according to a first embodiment. [Figure 6] 2 is a series of schematic cross-sectional views of a method for producing the catalytically active product of FIG. 1 according to a first embodiment. [Figure 7] 2 is a series of schematic cross-sectional views of a method for producing the catalytically active product of FIG. 1 according to a second embodiment. [Figure 8] 2 is a series of schematic cross-sectional views of a method for producing the catalytically active product of FIG. 1 according to a second embodiment. [Figure 9] 2 is a series of schematic cross-sectional views of a method for producing the catalytically active product of FIG. 1 according to a second embodiment. [Figure 10] 2 is a series of schematic cross-sectional views of a method for producing the catalytically active product of FIG. 1 according to a second embodiment. [Figure 11] 2 is a series of schematic cross-sectional views of a method for producing the catalytically active product of FIG. 1 according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] 1, a catalytically active product 10 according to the present invention is shown schematically. The catalytically active product 10 is configured to be used to promote a chemical reaction. For example, the catalytically active product 10 may be arranged for combustion, refining, catalytic reforming, etc. For example, the catalytically active product 10 may be arranged to purify flue gases of carbon monoxide and / or hydrocarbons such as VOCs and PAHs. For example, the catalytically active product 10 may be arranged in a reactor vessel for a chemical reaction. Alternatively, the catalytically active product 10 may be arranged in a burner for the combustion of a gaseous fuel such as natural gas, propane, butylene, or a similar gas, for example, for heating purposes.

[0018] The catalytically active product 10 includes a substrate 11, a first material 12, particles 13 of a second material, a ceramic layer 14 including a ceramic material having pores 15, and a catalytically active material 16. The first material 12 and the particles 13 form an attachment layer on the substrate 11. For example, the first material 12 is disposed directly on the substrate 11, with the particles 13 being partially embedded within the first material 12 and protruding from its surface. The ceramic layer 14 is disposed on top of the attachment layer formed by the first material 12 and the particles 13, with the ceramic layer 14 engaging the particles 13. Thus, the attachment layer formed by the first material 12 and the particles 13 is disposed between the substrate 11 and the ceramic layer 14.

[0019] In the illustrated embodiment, the substrate 11 has a generally flat shape. However, the substrate 11 may be flat, cylindrical, curved, bent, or have essentially any geometric shape. For example, the substrate 11 is formed as a mesh structure, i.e., a structure with a plurality of through holes. According to one embodiment, the substrate 11 is formed as a wire mesh. Alternatively, the substrate 11 is formed as a continuous sheet, a lattice structure, or the like. For example, the substrate 11 is or includes a metal or alloy. According to one embodiment, the substrate is made of steel, such as stainless steel, aluminum, or copper. Alternatively, the substrate 11 is made of a polymeric material, such as polytetrafluoroethylene or a similar polymer, or a composite material that can withstand relatively high temperatures. Generally, the substrate 11 should be able to withstand temperatures of at least 350°C. In some cases, it should be able to withstand temperatures much higher than this level, such as at least 500°C, at least 700°C, or at least 900°C.

[0020] A first material 12 is disposed on a substrate 11 that forms a base structure. The substrate 11, or at least a portion or side thereof, is coated with the first material 12. In the illustrated embodiment, only the top surface of the substrate 11 is coated with the first material 12. Alternatively, the entire substrate 11 is coated with the first material 12. For example, the first material 12 is a metal or alloy. For example, the first material 12 is Al or a similar metal with a relatively low melting point. Alternatively, the first material 12 is an alloy including a metal, such as Ni, Cu, Fe, and / or steel, and a melting point depressant.

[0021] The particles 13 are partially embedded in the first material 12 and at least partially protrude away from the substrate 11. The particles 13 are made of or include a second material having a higher melting point than the first material 12. For example, the solidus temperature of the second material particles 13 is higher than the liquidus temperature of the first material 12. For example, the second material particles 13 include a metal powder, a ceramic powder, or a mixture thereof. The particles 13 may have different shapes and sizes. The particles 13 are provided in or on the first material 12 to add surface roughness that aids in adhesion of the ceramic layer 14. For example, the particles 13 have a particle size of at least 10 μm, or at least 20 μm, e.g., 20-100 μm. For example, the second material has a porosity of at least 30%.

[0022] The ceramic layer 14 is provided on the attachment layer formed by the first material 12 and the particles 13 and is secured thereto by the particles 13. Thus, the particles 13 are partially embedded in the first material 12 and partially embedded in the ceramic layer 14, mechanically securing the ceramic layer 14 to the substrate 11. Thus, the ceramic layer 14 is disposed on the first material 12 and the particles 13 protruding therefrom. The ceramic layer 14 may comprise alumina, zirconia, titanium dioxide, silica, tungsten carbide, silicon nitride, or a similar ceramic, or a mixture thereof. Pores 15 are formed in the ceramic layer 14 to increase the surface area for depositing the catalytically active material 16 therein. Thus, the ceramic layer 14 is provided with the catalytically active material 16, and the catalytically active material 16 is disposed within the pores 15. For example, the catalytically active material 16 may be a noble metal, a transition metal, or a mixture or oxide thereof. For example, the catalytically active material 16 may be palladium.

[0023] Referring also to FIGS. 2-6, a method for producing a catalytically active product 10 is illustrated in a series of diagrams according to a first embodiment. The substrate 11 is described above and is illustrated schematically in FIG. 2. The substrate 11 is coated with a first material 12, for example, by a spraying process. A substrate 11 having the first material 12 is illustrated in FIG. 3, where the first material 12 is provided as a layer on the substrate 11. According to one embodiment, the first material 12 is provided as a suspension, i.e., the first material 12 is provided as particles dispersed in a liquid, such as water. For example, the substrate 11 is coated with the first material 12 by a spraying process, where the first material 12 is sprayed onto the substrate 11 at room temperature, for example. Thus, the first material 12 is not heated or sprayed at an elevated temperature. Alternatively, the first material 12 can be applied to the substrate 11 by another coating process, such as painting or dipping. Alternatively, the first material 12 can be provided as a paste, which is applied to the substrate 11 by spreading the paste over the surface of the substrate 11. After applying the first material onto the substrate, the substrate 11 with the first material 12 is optionally dried, for example by heat treatment in an oven.

[0024] After coating the substrate 11 with the first material 12, particles 13 containing a second material are provided on the first material 12, as shown in FIG. 4. For example, the particles 13 may be provided as a suspension, also called a slurry, in which the particles 13 are suspended in a liquid such as water. The suspension of particles 13 is then applied to the first material 12 supported by the substrate 11. For example, the particles 13 may be applied to the first material 12 by a spraying process, in which the suspension containing the particles 13 is sprayed onto the first material 12. Thus, the particles 13 may be sprayed onto the first material 12 at room temperature. After the particles 13 are applied to the first material 12, the substrate 11 carrying the first material 12 and particles 13 may be dried, for example, in an oven. The substrate 11 carrying the first material 12 and particles 13 is then heat-treated, for example, in a furnace, to a temperature that melts the first material 12 but does not melt the particles 13 of the second material. The substrate 11 is also not melted. Thus, the first material 12 is fixed to the substrate 11 by melting the particles 13 while fixing them to the first material 12. The particles 13 are mechanically fixed to the first material 12, and the particles 13 are partially embedded in the first material 12 after melting the first material 12. The first material 12 is also mechanically bonded to the substrate by melting into the roughness of its surface. Particles 13 partially embedded in and protruding from the first material 12 are shown in FIG. 4. For example, the heat treatment to melt the first material 12 can be performed under vacuum in a vacuum furnace. Alternatively, the heat treatment to melt the first material 12 can be performed using a reducing or inert gas in a furnace.

[0025] The substrate 11 carrying the first material 12 and particles 13 is then provided with a ceramic layer 14, as shown in FIG. 5. The ceramic layer 14 is provided on the particles 13 and the first material 12, such that the first material 12 is disposed between the ceramic layer 14 and the substrate 11. For example, the ceramic layer 14 is deposited on the attachment layer 12 as a slurry, such as an aqueous suspension. The ceramic layer 14 may also include a pore-forming agent to form a porous structure in the ceramic material. Typically, the thickness of the ceramic layer is in the range of 0.1 to 0.8 mm, preferably 0.2 to 0.5 mm. The ceramic layer 14 has an enlarged surface formed by pores 15, which are configured to hold catalytically active material 16, as shown in FIG. 6.

[0026] The ceramic layer 14 may be fabricated by the following processes: 1) direct spraying with secondary surface area expansion by precipitation; or 2) spraying with simultaneous deposition of ceramic powder; or a combination of methods 1) and 2), followed by coating with catalytically active material 16 through an impregnation process. Alternatively, the pore former may be a combustible material that can be burned by heat treatment. Optionally, the pore former may be a pore-forming polymeric material. Alternatively, the ceramic layer 14 is a ceramic powder containing particles with a high specific surface area. For example, pores 15 are formed in the ceramic layer 14 by conventional methods.

[0027] The pores 15 of the ceramic layer 14 are configured to support the catalytically active material 16. For example, the pores 15 may be cylindrical. In this way, the chemical to be purified can easily reach the catalytically active material 16 of the catalytically active product 10. The catalytically active material 16 may be deposited in the pores 15 of the ceramic layer by, for example, a conventional impregnation process. During impregnation, the structure of the pores 15 of the ceramic layer 14 is saturated with, for example, a solution containing the catalytically active material 16. The catalytically active material 16 may include a noble metal, a transition metal, or a combination thereof.

[0028] Referring to FIGS. 7-11, an alternative embodiment of the present invention is described in which a substrate 11 is coated with a mixture of a first material and particles 13 of a second material. A substrate 11 having a mixture of a first material 12 and particles 13 is shown in FIG. 7. For example, the first material 12 may also be provided as particles, and the first material 12 and particles 13 of the second material may be provided as a mixture in a slurry. A slurry containing both the first material 12 and particles 13 of the second material is applied to the substrate 11, as described above, for example, by spraying. Thus, the slurry may be provided on the substrate by spraying at room temperature. The substrate 11 containing the slurry is then optionally dried. After coating the substrate 11 with the mixture of the first material 12 and particles 13, the substrate 11 is heated to melt the first material 12 but not the substrate 11 or the second material, resulting in the particles 13 adhering to the first material 12 and the first material 12 adhering to the substrate 11, as shown in FIG. 8. Thus, the particles 13 are partially embedded in the first material 12 and protrude away from the substrate 11, providing a rough outer surface for securing the ceramic layer 14 as described above. The ceramic layer 14, which may be provided as a slurry, is then deposited on the first material 12 and the particles 13, as shown in FIG. 9. For example, the ceramic layer may be deposited by spraying, as described above. Next, as shown in FIG. 10, the ceramic layer 14 may be subjected to a surface area enlargement treatment to form pores 15. For example, the ceramic layer 14 may include a pore-forming agent. Finally, the catalytically active material 16 is deposited, for example, by impregnation. The catalytically active material 16 may be deposited on the surface of the ceramic layer 14 and inside its pores 15.

[0029] The particles are provided in first material 12 to add surface roughness that aids in the adhesion of subsequently deposited ceramic layer 14. In other words, providing first material 12 with rough particles can provide an increased surface area for improved adhesion of ceramic material 14 to substrate 11. Upon heating, first material 12 fuses to substrate 11, exposing contained particles 13. Exposing particles 13 allows ceramic layer 14 to be secured to substrate 11 due to the increased surface area and roughness provided by particles 13.

Claims

1. A process for producing a catalytically active product (10), comprising the steps of: a) providing a substrate (11); b) depositing a first material (12) and particles (13) of a second material on the substrate, the particles (13) of the second material having a higher melting point than the first material (12); c) heating the substrate (11) having the first material (12) and the particles (13) to a temperature that melts the first material (12) but does not melt the particles (13) of the second material, thereby adhering the first material (12) and the particles (13) to the substrate (11), the particles (13) being partially embedded in the first material (12) and forming a roughened surface; d) depositing a ceramic material on the roughened surface formed by the particles (13) to form a ceramic layer (14) thereon; e) adding catalytically active material (16) to said ceramic layer (14); A method comprising:

2. 2. The method of claim 1, further comprising the step of providing the first material (12) in the form of a suspension and spraying the first material (12) onto the substrate (11) in step b).

3. The method of claim 2, wherein the first material (12) is sprayed onto the substrate at room temperature.

4. 4. The method according to claim 1, further comprising, in step b), providing the particles (13) of the second material as a suspension and spraying the suspension together with the first material onto the substrate (11), or spraying the particles (13) of the second material onto the first material (12) provided on the substrate (11).

5. 5. The method of claim 4, wherein the particles (13) of the second material are sprayed at room temperature.

6. 4. The method according to claim 1, further comprising, in step c), heating the substrate (11) with the particles (13) of the first material (12) and the second material in a vacuum and / or in an inert gas and / or a reducing gas.

7. 4. The method according to claim 1, further comprising, in step d), providing the ceramic material as a suspension and spraying the ceramic material onto the first material (12) and the particles (13) to form the ceramic layer (14).

8. The method of claim 7 , wherein the ceramic material is sprayed at room temperature.

9. The method of any one of claims 1 to 3, including the step of providing pores (15) in the ceramic layer (14).

10. The method of claim 9, wherein the step of providing pores (15) in the ceramic layer (14) comprises precipitation or combustion.

11. The method according to any one of claims 1 to 3, comprising in step e) adding the catalytically active material (16) to the ceramic layer (14) by impregnation, dipping or spraying.

12. The method according to any one of claims 1 to 3, wherein the substrate (11) is metallic.

13. The method according to any one of claims 1 to 3, wherein the first material (12) is a metal or an alloy.

14. The method according to any one of claims 1 to 3, wherein the particles (13) of the second material comprise metal and / or ceramic powders or composites thereof.

15. The method according to any one of claims 1 to 3, wherein the particles (13) of the second material have a porosity of at least 30% and / or present a roughness of at least 10 μm.

16. The method of any one of claims 1 to 3, wherein the catalytically active material comprises a noble metal, a transition metal, or a mixture or oxide thereof.

17. The method according to any one of claims 1 to 3, further comprising a drying process between steps b) and c) and / or between the steps of applying the first material (12) and the particles (13).

18. A catalytically active product, 1. A catalytically active product comprising: a substrate (11); a first material (12); particles (13) of a second material having a higher melting point than the first material; and a ceramic layer (14) bonded to the substrate (11) via the first material (12) and the particles (13) of the second material partially embedded in the first material (12) and protruding into the ceramic layer (14), wherein pores (15) containing a catalytically active material (16) are formed in the ceramic layer (14).

19. 19. The catalytically active product of claim 18, wherein the substrate (11) comprises a metal, the first material (12) comprises a metal, and the particles (13) of the second material comprise a metal powder, a ceramic powder, or a mixture or composite thereof.

20. 20. A catalytically active product according to claim 18 or 19, wherein the catalytically active material (16) comprises a noble metal, a transition metal, or a mixture or oxide thereof.

21. Catalytically active product according to claim 18 or 19, wherein the particles (13) of the second material have a particle size of 20 to 100 μm.

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