Catalyst carrier, catalytic material and preparation method

Abstract

The invention discloses a catalyst carrier, a catalytic material and a preparation method. The preparation method of the catalyst carrier comprises the following steps: uniformly mixing metal powder, an additive and water to form slurry; the slurry is attached to a foamed nickel base material through a slurry hanging method / spraying method, and then the catalyst carrier is prepared through drying and sintering. According to the preparation method, the metal powder is loaded on the foamed nickel substrate by adopting a slurry hanging method, and sintering treatment is performed, so that the specific surface area of the foamed nickel substrate is remarkably increased, meanwhile, good air permeability and loading performance are kept, and the catalytic performance of a catalytic material prepared by taking the foamed nickel substrate as a carrier is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst carriers, and particularly to catalyst carriers, catalytic materials and preparation methods. Background Art

[0002] Catalyst carriers play a crucial role in catalytic reactions and can provide efficient catalyst support. However, most of the existing catalyst carrier materials have problems such as small specific surface area, poor air permeability, insufficient loading capacity, etc., resulting in low catalytic reaction efficiency, and the service life and performance of the catalyst are limited.

[0003] For example, although nickel foam has good air permeability and high mechanical strength as a catalyst carrier, due to its small specific surface area, it is often difficult to meet the requirements of efficient catalytic reactions. While some traditional catalyst carriers can provide a large specific surface area, their air permeability and loading capacity are relatively poor, restricting the improvement of catalytic effects. Summary of the Invention

[0004] Based on the technical problems existing in the background art, the present invention proposes a catalyst carrier, a catalytic material and a preparation method, which significantly improve the specific surface area of the nickel foam matrix, and at the same time maintain good air permeability and loading performance, ensuring the catalytic performance of the catalytic material prepared with this nickel foam matrix as the carrier.

[0005] A preparation method of a catalyst carrier proposed by the present invention has the following method steps:

[0006] S11: Mix metal powder, additive and water evenly to form a slurry;

[0007] S12: Adhere the slurry to the nickel foam substrate by the slurry coating method / spraying method, and then dry and sinter to obtain the catalyst carrier.

[0008] Preferably, the metal powder in S11 is one or more of stainless steel 316L, stainless steel 310S and stainless steel 904L; the additive is sodium carboxymethylcellulose.

[0009] Preferably, the mass ratio of the metal powder to the additive is 100:1 - 5, and the loading amount of the slurry on the nickel foam substrate is 50 - 250 g / m 2 .

[0010] Preferably, the drying conditions are: temperature 200 - 400 °C, and the running speed of the nickel foam substrate is 0.2 - 2 m / min.

[0011] Preferably, the sintering conditions are: temperature 800 - 1200 °C, and time 24 - 48 h.

[0012] A catalyst support proposed by the present invention is prepared by the above-mentioned preparation method.

[0013] A preparation method of a catalytic material proposed by the present invention is to load a catalyst on the above-mentioned catalyst support, and the method steps are as follows:

[0014] S21: Mix the catalyst powder, binder, modifier and water into a slurry;

[0015] S22: Immerse the catalyst support in the slurry and dry it to obtain the catalytic material.

[0016] Preferably, the binder is one or more of silica sol, alumina sol, titania sol and silicone binder; the modifier is one or more of dispersant, thickener and surfactant.

[0017] A catalytic material proposed by the present invention is prepared by the above-mentioned preparation method.

[0018] The beneficial technical effects of the present invention:

[0019] (1) In the present invention, by loading metal powder on the nickel foam matrix and after sintering treatment, convex metal particles are attached between the surface and the skeleton of the nickel foam skeleton, and the specific surface area of the nickel foam matrix is significantly improved; in addition, while increasing the specific surface area of the nickel foam substrate, the present invention also ensures a certain air permeability, ensuring that the prepared catalyst support has a certain air permeability and avoiding blockage of the catalytic material formed after the catalyst is loaded on the catalyst support during the high-efficiency reaction.

[0020] (2) The catalytic material prepared with the catalyst support of the present invention has excellent catalytic performance and is particularly suitable for industrial catalytic reactions that require high-efficiency catalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 SEM images of the catalyst support 1 prepared in Example 1 proposed by the present invention at different magnifications;

[0022] Figure 2 SEM images of the catalyst support 2 prepared in Example 2 proposed by the present invention at different magnifications;

[0023] Figure 3 SEM images of the catalyst support 3 prepared in Example 3 proposed by the present invention at different magnifications;

[0024] Figure 4 SEM images of the catalyst support 4 prepared in Example 4 proposed by the present invention at different magnifications;

[0025] Figure 5SEM images of the catalyst support 5 prepared in Example 5 of the present invention at different magnification factors. Detailed implementation

[0026] The present invention will be further explained below with reference to specific examples.

[0027] Example 1

[0028] The metal powder, sodium carboxymethylcellulose and water are stirred at a high speed of 3000 r / min to form a slurry. The nickel foam substrate is immersed in the slurry for 30 minutes and then taken out. The amount of slurry adhered is controlled to be 70 g / m 2 , and then preliminary drying is carried out. The drying temperature is 300 °C, and the continuous running speed is 1 m / min. After preliminary drying, the substrate is rolled into 30 m / roll and placed in a vacuum sintering furnace. The temperature is set in the range of 1000 °C, and sintering is carried out for 24 h to make the surface and between the skeletons of the nickel foam skeleton adhere to convex metal particles, denoted as catalyst support 1.

[0029] Among them, the mass ratio of the metal powder to sodium carboxymethylcellulose is 50:1, and the concentration of sodium carboxymethylcellulose in the slurry is 1%.

[0030] The catalyst powder, binder, modifier and pure water are stirred to make a slurry with a solid content of 30%. Stir well at a speed of 2000 r / min for 30 minutes, and then pour the slurry into the slurry hanging pool; put the catalyst support 1 into the slurry hanging pool, take it out after sufficient impregnation, and carry out continuous drying. It is divided into 6 temperature sections, set as 100 °C in zone 1, 260 °C in zone 2, 260 °C in zone 3, 260 °C in zone 4, 260 °C in zone 5, and 200 °C in zone 6. The temperature deviation of each zone is controlled within ±30 °C, and the baking speed is controlled at 1 m / min. After drying, it is wound up, denoted as catalytic material 1.

[0031] Among them, the catalyst used in this example is a vanadium-titanium-based catalyst, the main components are TiO2 and V2O5, and the mass ratio of TiO2 to V2O5 is 9:1. For the catalyst support of the present invention, it is not limited to only loading the vanadium-titanium-based catalyst in this example. The binder is polyvinyl alcohol (PVA), and the concentration in the slurry is 5%. Modifier: ammonium polyacrylate (PAAm), the concentration in the slurry is 1%. The modifier can be a dispersant, thickener or surfactant. Loading the catalyst on the support by using the existing technology can meet the requirements.

[0032] Example 2

[0033] The metal powder, sodium carboxymethylcellulose and water are stirred at a high speed of 3000 r / min to form a slurry. The nickel foam substrate is immersed in the slurry for 30 minutes and then taken out. The amount of slurry adhered is controlled to be 190 g / m 2, and the remaining conditions are the same as those in Example 1. The prepared catalyst support is denoted as catalyst support 2, and the catalytic material is denoted as catalytic material 2.

[0034] Example 3

[0035] The metal powder, sodium carboxymethylcellulose, and water were vigorously stirred at a speed of 3000 r / min to form a slurry. The nickel foam substrate was immersed in the slurry and taken out after 30 min, and the amount of slurry adhered was controlled to be 250 g / m 2 , and the remaining conditions are the same as those in Example 1. The prepared catalyst support is denoted as catalyst support 3, and the catalytic material is denoted as catalytic material 3.

[0036] Example 4

[0037] The metal powder, sodium carboxymethylcellulose, and water were vigorously stirred at a speed of 3000 r / min to form a slurry. The slurry was evenly sprayed onto the nickel foam substrate by the spraying method, and the amount of slurry adhered was controlled to be 70 g / m 2 , and the remaining conditions are the same as those in Example 1. The prepared catalyst support is denoted as catalyst support 4, and the catalytic material is denoted as catalytic material 4.

[0038] Comparative Example

[0039] Sodium carboxymethylcellulose and water were vigorously stirred at a speed of 3000 r / min to form a slurry, and the concentration of sodium carboxymethylcellulose in the slurry was 1%; then, preliminary drying was carried out at a drying temperature of 300 °C and a continuous running speed of 1 m / min. After preliminary drying, the substrate was wound into rolls of 30 m / roll and placed in a vacuum sintering furnace, and the temperature was set in the range of 1000 °C for 24 h of sintering, denoted as catalyst support 5.

[0040] The specific surface area and air permeability of catalyst supports 1-5 were measured, and the test results are shown in Table 1.

[0041] Detection method for specific surface area: static volumetric method, the execution standard is GB / T 19587-2004 "Determination of Specific Surface Area of Solid Substances by Gas Adsorption BET Method", and the instrument used is Micromeritics ASAP 2460.

[0042] Detection method for air permeability: the execution standard is GB / T 5453-1985 "Test Method for Air Permeability of Fabrics".

[0043] Table 1 Test Results of Catalyst Support Performance

[0044] Group <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Air permeability (m 3 / m 2 ·h·kPa)]]> Nickel foam substrate 50 4000 Catalyst support 1 400 2300 Catalyst support 2 460 1800 Catalyst support 3 450 1600 Catalyst support 4 300 2500 Catalyst support 5 55 3700

[0045] As can be seen from the test results in Table 1, whether the composite metal powder is applied to the nickel foam substrate by the slurry coating method or the spraying method, the specific surface area of the nickel foam substrate can be significantly increased. This is because after loading the metal powder on the nickel foam matrix and sintering treatment, raised metal particles adhere between the surface and the framework of the nickel foam skeleton. In addition, different slurry coating amounts and different slurry coating methods have certain effects on the specific surface area of the catalyst support. From the performance of catalyst supports 2 and 3, it can be seen that too high a slurry coating amount will cause some metal powders to aggregate or pore channels to be blocked, thus reducing the effective surface area of the catalyst support. From the performance of catalyst supports 1 and 4, it can be seen that the specific surface area of the catalyst support prepared by the spraying method is smaller than that of the slurry coating method. This is because in the spraying method, the solution containing metal powder is sprayed onto the nickel foam at high speed. During the high-speed spraying process of the metal powder solution, most of the metal powders pass through the framework structure of the nickel foam, and only the metal powders directly intercepted by the framework structure adhere to the nickel foam. Therefore, the spraying method results in fewer metal powders adhering to the surface of the nickel foam, with uniform adhesion but a lower total amount, making the specific surface area of the catalyst support prepared by the spraying method lower than that of the slurry coating method.

[0046] In terms of the gas permeability of the catalyst support, the catalyst support prepared by the method of the present invention can still maintain a certain gas permeability, avoiding the blockage phenomenon of the catalytic material formed after loading the catalyst in the high-efficiency reaction. From the performance of catalyst supports 1 - 3, it can be seen that as the amount of metal powder loaded on the nickel foam matrix increases, the gas permeability shows a downward trend. This is because more metal powders adhere to the pore walls of the nickel foam, resulting in some pore channels becoming narrower or blocked, reducing the gas flow capacity. The gas permeability of catalyst support 4 prepared by the spraying method is higher than that of catalyst support 1 prepared by the slurry coating method because the metal powder distribution of the spraying method is thinner and more uniform, and the pore channels maintain a higher degree of smoothness.

[0047] Figures 1-5 Figs. - Figures 1-5 are SEM images of catalyst supports 1 - 5. The pore structure of the nickel foam of catalyst support 1 is clearly visible. Only a thin layer of metal powder adheres to the pore walls, and the overall surface is still relatively smooth, and the original nickel foam skeleton is basically maintained; the amount of metal powder adhering to the pore walls of the nickel foam of catalyst support 2 has increased significantly, with a wide coverage range, and thicker powder accumulations have appeared at the edges of some pores; the pore walls of the nickel foam of catalyst support 3 are completely covered by metal powder, and the adhesion layer has thickened significantly, and the pores in some areas are almost filled with powder; the three-dimensional network structure of the nickel foam of catalyst support 4 is clearly visible, the macroscopic pore structure remains intact, and a relatively uniform layer of metal powder adheres to the pore walls, with a large coverage area; the three-dimensional network structure of the nickel foam of catalyst support 5 is clearly visible, and the pore walls are smooth without any attachments.

[0048] The catalytic materials 1-4 were respectively made into round sheets and placed in the SCR catalyst evaluation device for denitrification tests. The concentrations (vol%) of each gas were controlled by a mass flow meter: NO: 500 ppm, NH3: 500 ppm, O2: 5%, H2O: 15%, and N2 was the balance gas. The filtration air velocity was 1 m / min. The denitrification rate calculation formula is η=(C1 - C2) / C1×100%, where C1 is the concentration at the inlet of NO x and C2 is the concentration at the outlet of NO x , which was obtained by flue gas analysis and testing. The test results are shown in Table 2.

[0049] Table 2 Test results of denitrification performance of catalytic materials at different temperatures

[0050]

[0051]

[0052] It can be seen from the test results in Table 2 that the overall performance of catalytic material 2 is the best. Especially at low temperature (260°C) and medium temperature (300°C), the efficiency is significantly higher than that of other examples, indicating that more active sites brought by the high specific surface area have a direct promoting effect on the denitrification efficiency, especially under low temperature and medium temperature conditions. The performance of catalytic material 3 is stable at all temperature points, and there is almost no difference in performance from catalytic material 2 above 300°C, indicating that the medium-high specific surface area may optimize the air permeability while ensuring the denitrification efficiency, and has a balancing effect on the overall performance. For catalytic material 4, although the specific surface area of the catalyst carrier prepared by the spraying method is relatively low, it has a high air permeability, which is more conducive to the mass transfer and diffusion of reaction gases under high temperature conditions, thus improving the catalytic efficiency under high temperature conditions. The overall performance of catalytic material 1 is the worst, especially the catalytic efficiency is low at 260°C low temperature, indicating that the insufficient specific surface area of the catalyst carrier limits the number of catalytic active sites, and the performance improves at high temperature, but it is still lower than other catalytic materials.

[0053] Although the embodiments of the present application have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present application. The scope of the present application is defined by the appended claims and their equivalents, and should be included within the protection scope of the present application.

Claims

1. A method for preparing a catalyst support, characterized in that, The method steps are as follows: S11: Mix metal powder, additive and water evenly to form a slurry; S12: Adhere the slurry onto a nickel foam substrate by the slurry coating method / spraying method, and then obtain a catalyst support through drying and sintering.

2. The preparation method of the catalyst carrier according to claim 1, characterized in that, In S11, the metal powder is one or more of stainless steel 316L, stainless steel 310S and stainless steel 904L; the additive is sodium carboxymethyl cellulose.

3. The preparation method of the catalyst carrier according to claim 1, characterized in that, The mass ratio of the metal powder to the additive is 100:1 - 5; the loading amount of the slurry on the nickel foam substrate is 50 - 250 g / m 2 .

4. The preparation method of the catalyst carrier according to claim 1, characterized in that, The drying conditions are: temperature 200 - 400 °C, and the running speed of the nickel foam substrate is 0.2 - 2 m / min.

5. The preparation method of the catalyst carrier according to claim 1, characterized in that, The sintering conditions are: temperature 800 - 1200 °C, and time 24 - 48 h.

6. A catalyst support, characterized in that, It is obtained by using the preparation method described in any one of claims 1 - 5.

7. A method for preparing a catalytic material, wherein the catalyst is loaded on the catalyst carrier described in claim 6, characterized in that, The method steps are as follows: S21: Mix catalyst powder, binder, modifier and water to form a slurry; S22: Immerse the catalyst support in the slurry, and obtain a catalytic material after drying.

8. The method for preparing a catalytic material according to claim 7, characterized in that, The binder is one or more of silica sol, alumina sol, titania sol and silicone binder; the modifier is one or more of dispersant, thickener and surfactant.

9. A catalytic material, characterized in that, It is obtained by using the preparation method described in claim 7 or 8.

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