KR101068543B1 - Mixtured Catalyst For Emission Reduction Device Of Diesel Vehicles And Preparing Method For The Same - Google Patents

Abstract

The present invention relates to a mixed catalyst for reducing the exhaust gas of a diesel vehicle. In detail, the mixed catalyst includes an oxide of one or two or more metals selected from Ti, Zr, Si, Al, and Ce, a composite active metal of platinum and tungsten, beta-zeolite, an inorganic binder, and a dispersant. The average particle diameter of the oxide of the metal is characterized by being larger than the average particle diameter of the composite active metal.

In addition, the present invention provides a method for producing a mixed catalyst for reducing the exhaust gas of a diesel vehicle. In detail, the preparation method is to prepare a mixture powder by supporting a solution in which a composite active metal of platinum and tungsten is dissolved in an oxide of one or two or more metals selected from the group consisting of Ti, Zr, Si, Al, and Ce. Step, drying and calcining the mixture powder to obtain a catalyst powder and mixing the catalyst powder with beta-zeolite, inorganic binder and dispersant to obtain a mixed catalyst for the exhaust gas reduction device of a diesel vehicle.

The exhaust gas reducing device coated with the mixed catalyst for the exhaust gas reducing device of the diesel vehicle of the present invention can secure a large area in contact with a reactant such as the exhaust gas, and thus, such as unburned hydrocarbons, carbon monoxide and nitrogen monoxide. The oxidation rate of contaminants can be improved, and the PM (particulate matter in exhaust gas) removal efficiency can be improved.

Catalyst coating, diesel oxidation catalyst, diesel particulate filter, nitrogen monoxide oxidation, PM removal efficiency, post treatment technology

Description

Mixed Catalyst For Emission Reduction Device Of Diesel Vehicles And Preparing Method For The Same}

The present invention relates to a mixed catalyst for reducing exhaust gas of a diesel vehicle and a method of manufacturing the same. The exhaust gas reducing device coated with the mixed catalyst can secure a large area in contact with the reactants such as the exhaust gas, thereby improving the oxidation rate of contaminants such as unburned hydrocarbons, carbon monoxide and nitrogen monoxide, and removing PM. High efficiency

Automotive emissions generally refer to gases produced by mixer combustion in an engine and released into the atmosphere through exhaust pipes. These emissions include a large amount of substances harmful to the human body, such as carbon monoxide (CO), nitrogen oxides (NOx), unburned hydrocarbons (HC). Therefore, prevention of air pollution caused by automobile emissions has emerged as an important issue for environmental hygiene, and regulations are required to clean up before emitting emissions from automobiles.

On the other hand, diesel vehicles, which have relatively high emissions of harmful emissions, have excellent amounts of nitrogen oxides and particulate matter (PM, Particulate Matter) in the exhaust gases, unlike gasoline vehicles, despite excellent fuel economy and output. . As such, in a diesel vehicle, carbon monoxide and hydrocarbons are emitted much less than gasoline vehicles because air is sufficiently burned under most driving conditions, but nitrogen oxides and particulate matter are emitted. In addition, particulate matter has recently been identified as the main cause of air pollution, and has been found to cause many harms to the human body. Therefore, the emission reduction technology of diesel vehicles has been studied with a focus on the reduction of particulate matter including nitrogen oxides and soot (soot).

Recently, research on soot filtration filters has been actively conducted as a post-treatment technology to cope with strengthening emission standards of diesel vehicles. In addition, studies have been actively conducted on the mixed catalyst for the exhaust gas reducing device of a diesel vehicle in which the particulate filter can increase the removal efficiency of particulate matter.

The present invention for solving the above problems, coated on the exhaust gas reduction device of diesel vehicles, the oxidation efficiency of unburned hydrocarbons, carbon monoxide, nitrogen oxides and PM (particulate matter in exhaust gas) harmful to the human body and nano carbon below 30nm An object of the present invention is to provide a mixed catalyst for the exhaust gas reducing device of a diesel vehicle that can improve the particle collection efficiency.

The present invention for achieving the above object, an oxide of one or two or more metals selected from Ti, Zr, Si, Al and Ce, a composite active metal of platinum and tungsten, beta-zeolite, inorganic binder, dispersant It provides a mixed catalyst for the exhaust gas reducing device of the diesel vehicle. Preferably, the average particle diameter of the oxide of the metal is larger than the average particle diameter of the composite active metal.

In addition, the present invention for achieving the above object is to support a solution in which a composite active metal of platinum and tungsten is dissolved in an oxide of one or two or more metals selected from the group consisting of Ti, Zr, Si, Al and Ce Preparing a mixture powder, drying and firing the mixture powder to obtain a catalyst powder, and mixing the catalyst powder with beta-zeolite, an inorganic binder and a dispersant to obtain a mixed catalyst for an exhaust gas reducing device of a diesel vehicle. It provides a method for producing a mixed catalyst for the exhaust gas reducing device of a diesel vehicle comprising.

When the mixed catalyst for the exhaust gas reducing device of the diesel vehicle of the present invention is coated on the exhaust gas reducing device, the mixed catalyst of the small particle of the present invention is uniformly dispersed on the surface of the beta-zeolite having a large particle size, thereby providing a wide catalyst area. can do. As a result, the exhaust gas reducing device coated with the mixed catalyst of the present invention is capable of reducing the oxidation efficiency of unburned hydrocarbons, carbon monoxide, nitrogen oxides and PMs (particulate matter in exhaust gas) and the collection efficiency of nanocarbon particles of 30 nm or less, which are harmful to the human body. It can be promoted.

The present invention relates to a mixed catalyst for the exhaust gas reducing device of a diesel vehicle, an oxide of one or two or more metals selected from Ti, Zr, Si, Al and Ce, a composite active metal of platinum and tungsten, beta-zeolite, Inorganic binder and dispersant.

Since the average particle diameter of the metal oxide is larger than the average particle diameter of the composite active metal, and the average particle diameter is different from each other, when the mixed catalyst of the present invention is coated on the exhaust gas reducing device of a diesel vehicle, the contact area between the mixed catalyst and the exhaust gas may be improved. Can be. As a result, the exhaust gas reduction device of the diesel vehicle coated with the mixed catalyst can improve the oxidation efficiency of PM (Particulate Matter) harmful to the human body and the collection efficiency of nano carbon particles of 30 nm or less. .

The average particle diameter of the oxide of the metal may be 0.1 ~ 20㎛. Preferably, the average particle diameter of the oxide of the metal may be 0.3 ~ 2㎛.

The average particle diameter of the composite active metal may be 0.01 ~ 5.0㎛. Preferably, the average particle diameter of the composite active metal may be 0.02 ~ 1.0㎛.

The inorganic binder may comprise alumina, titania or silicon.

The dispersant may be water or alcohol.

The metal oxide and the composite active metal may be mixed in a weight ratio of 10 to 90:90 to 10. Preferably, the oxide of the metal and the composite active metal may be mixed in a weight ratio of 25 to 65: 35 to 75.

In addition, the present invention relates to a method for producing a mixed catalyst for reducing the exhaust gas of a diesel vehicle. In detail, the preparation method is to prepare a mixture powder by supporting a solution in which a composite active metal of platinum and tungsten is dissolved in an oxide of one or two or more metals selected from the group consisting of Ti, Zr, Si, Al, and Ce. Step, drying and calcining the mixture powder to obtain a catalyst powder and mixing the catalyst powder with beta-zeolite, inorganic binder and dispersant to obtain a mixed catalyst for the exhaust gas reduction device of a diesel vehicle.

The drying is carried out in an air atmosphere for 12 hours at 105 ℃, the firing is preferably carried out in an air atmosphere of 550 ℃.

Hereinafter, with reference to the preferred production examples, examples and comparative examples of the present invention will be described in detail. The following Preparation Examples, Examples and Comparative Examples are only presented to understand the content of the present invention, and those skilled in the art will be capable of many modifications within the technical spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited to these preparation examples, examples and comparative examples.

Production Example 1 Mixing Catalyst for Emission Reduction Device for Diesel Vehicle

Titanium dioxide (TiO ₂ ), which is an oxide of Ti, was dried at 105 ° C. for 12 hours to remove adsorbed moisture and volatile organics, and then cooled to room temperature to prepare 500 g of pure titanium dioxide.

Next, 10 g of H ₂ PtCl ₆ .xH ₂ O (Aldrich Co.) and 25 g of Ammonium Tungstate (Aldrich Co.) were dissolved in distilled water to prepare a solution in which the composite active metal was dissolved.

Thereafter, a mixture powder was prepared by supporting a solution in which the composite active metal was dissolved in pure titanium dioxide. The mixture powder was dried in an air atmosphere at 105 ° C. for 12 hours, and then calcined in an air atmosphere at 550 ° C. to obtain 350 g of catalyst powder (Pt-W / TiO ₂ ).

The Pt-W / TiO ₂ was ground in an attrition mill for 10 minutes to have an average particle diameter of 0.05 μm or less. The pulverized Pt-W / TiO ₂ was mixed with 150 g of beta-zeolite having an average particle diameter of 0.5 μm or less, 166 g of alumina sol, and 780 g of distilled water to obtain a mixed catalyst for an exhaust gas reducing device of a diesel vehicle of the present invention. The alumina sol was used as an inorganic binder and the distilled water was used as a dispersant.

Example 1 Coating of DOC Support / Ceramic Filter Using Mixed Catalyst of the Present Invention

In this embodiment, the DOC support / ceramic filter made of cordierite, which is a kind of exhaust gas reducing device of a diesel vehicle, is coated by using a mixed catalyst for the exhaust gas reducing device of the diesel vehicle of the present invention manufactured in Preparation Example 1 above. It was. The DOC refers to a diesel oxidation catalyst.

First, per unit volume (1L) of the DOC support / ceramic filter, washcoating was carried so that 60 g of the mixed catalyst for the exhaust gas reducing device of the diesel vehicle of Preparation Example 1 was supported.

Next, the DOC support / ceramic filter was dried at 80 ° C. for 28 hours, and then calcined at 550 ° C. for 4 hours in an air atmosphere. Thereafter, the mixture was reduced at 300 ° C. for 2 hours under the condition that 20 vol% H ₂ / N ₂ mixed gas flowed. As a result, a DOC support / ceramic filter coated with a mixed catalyst of the present invention was obtained, and a schematic diagram thereof is shown in FIG. 1. As shown in the schematic diagram, it can be seen that in the DOC support / ceramic filter coated with the mixed catalyst of the present invention, the mixed catalyst of the small particle size of the present invention is evenly dispersed on the surface of the beta-zeolite having a large particle size.

In addition, in Figure 2a, the surface of the DOC support / ceramic filter coated with the mixed catalyst of the present invention is shown in the SEM photograph. In Figure 2b, a cross-sectional view of the surface of the DOC support / ceramic filter coated with the mixed catalyst of the present invention is shown in SEM photographs. As shown in FIG. 2A and FIG. 2B, the beta-zeolite forms a porous structure, and the mixed catalyst of the present invention having a small particle size is uniformly dispersed on the surface of the beta-zeolite having a large particle diameter to react with the exhaust gas of a diesel vehicle. It can be seen that the catalyst area can be large.

Example 2 Coating of DOC Support / Ceramic Filter Using Pt-W / TiO ₂

In this example, the DOC support / ceramic filter was coated using Pt-W / TiO ₂ shown in Preparation Example 1.

First, 60 g of Pt-W / TiO ₂ was coated per 1 L of DOC support / ceramic filter unit made of cordierite.

Next, the DOC support / ceramic filter was dried at 105 ° C. for 10 hours, and then calcined at 550 ° C. for 4 hours in an air atmosphere. Thereafter, the mixture was reduced at 300 ° C. for 2 hours under the condition that 20 vol% H ₂ / N ₂ mixed gas flowed. As a result, a DOC supporter / ceramic filter coated with Pt-W / TiO ₂ was obtained, and a schematic diagram thereof is shown in FIG. 3. As shown in the schematic diagram, the DOC support / ceramic filter is coated with Pt-W / TiO ₂ having a uniform particle diameter, and thus has a narrow catalytic surface area capable of reacting with the exhaust gas of a diesel vehicle.

In FIG. 4A, the coated surface of the DOC support / ceramic filter is shown by SEM photograph. In FIG. 4B, the cross section of the coated surface of the DOC support / ceramic filter is shown in SEM image. As shown in FIGS. 4A and 4B, when only Pt-W / TiO ₂ having a fine particle diameter is coated on the DOC support / ceramic filter, the porosity in the Pt-W / TiO ₂ layer is low to react with the exhaust gas of the diesel vehicle. narrow the area of the Pt-W / TiO ₂ that can be seen that the.

<Comparative Example 1>: PM removal efficiency at a driving speed of 60 km / hr

Experiments comparing the PM removal efficiency of the DOC support / ceramic filter coated with the mixed catalyst of the present invention of Example 1 and the DOC support / ceramic filter coated with Pt-W / TiO ₂ of Example 2 were carried out. The DOC scaffolds / ceramic filters of Examples 1 and 2 were each canned to be attached to a vehicle, attached to a vehicle equipped with a 3.0L TCl engine, and had an average operating speed of 60 km / hr. Cumulative amount was measured.

As a control, an uncoated DOC support / ceramic filter was attached to a vehicle equipped with a 3.0L TCl engine to measure the cumulative amount of PM per mileage under conditions of an average running speed of 60 km / hr. The experimental results are shown in Table 1 below.

TABLE 1

PM cumulative speed (g / hr) PM removal efficiency (%) Example 1 One 77.8 Example 2 2 55.5 Control group 4.5 -

As can be seen in Table 1, the PM cumulative rate is 1 g / hr when using the mixed catalyst coated DOC support / ceramic filter (Example 1) of the present invention, the uncoated DOC support / ceramic filter ( PM cumulative rate was 4.5g / hr. That is, in the present invention, the PM removal efficiency reaches 77.8%. On the other hand, when using the DOC support / ceramic filter (Example 2) coated with Pt-W / TiO ₂ PM accumulation rate is 2g / hr, PM removal efficiency is only 55.5%.

That is, it can be seen that the PM removal efficiency is excellent when the DOC support / ceramic filter is coated using the mixed catalyst of the present invention.

<Comparative Example 2>: PM removal efficiency at a driving speed of 100 km / hr

Experiments comparing the PM removal efficiency of the DOC support / ceramic filter coated with the mixed catalyst of the present invention of Example 1 and the DOC support / ceramic filter coated with Pt-W / TiO ₂ of Example 2 were carried out. The DOC scaffolds / ceramic filters of Examples 1 and 2 were each canned to be attached to a vehicle, attached to a vehicle equipped with a 3.0L TCl engine, and had an average operating speed of 100 km / hr. Cumulative amount was measured.

As a control, an uncoated DOC support / ceramic filter was attached to a vehicle equipped with a 3.0L TCl engine to measure the cumulative amount of PM per mileage under conditions of average driving speed of 100 km / hr. The experimental results are shown in Table 2 below.

TABLE 2

PM cumulative speed (g / hr) PM removal efficiency (%) Example 1 -6 230 Example 2 -2 144 Control group 4.5 -

As can be seen in Table 2 above, when the DOC support / ceramic filter (Example 1) coated with the mixed catalyst of the present invention was used, the PM accumulation rate was -6 g / hr, and the uncoated DOC support / ceramic filter was When using (control), the cumulative PM rate was 4.5 g / hr. That is, in the present invention, the PM removal efficiency reaches 230%, while the PM cumulative rate when the DOC support / ceramic filter (Example 2) coated with Pt-W / TiO ₂ is used is -2 g / hr. The PM removal efficiency was only 144%.

From the above results, it can be seen that the PM removal efficiency is excellent when the DOC support / ceramic filter is coated using the mixed catalyst of the present invention.

The present invention has been described above in connection with specific embodiments of the present invention, but this is only an example and the present invention is not limited thereto. Those skilled in the art can change or modify the described embodiments without departing from the scope of the present invention, and such changes or modifications are within the scope of the present invention. In addition, the materials of each component described herein can be easily selected and replaced by a variety of materials known to those skilled in the art. Those skilled in the art can also omit some of the components described herein without degrading the performance or add the components to improve performance. In addition, those skilled in the art may change the order of the method steps described herein according to the process environment or equipment. Therefore, the scope of the present invention should be determined by the appended claims and equivalents thereof, not by the embodiments described.

Figure 1 shows a schematic diagram of the DOC support / ceramic filter coated with a mixed catalyst for the exhaust gas reducing device of the present invention.

Figure 2a is a SEM photograph of the surface of the DOC support / ceramic filter coated with the mixed catalyst of the present invention of Preparation Example 1. Figure 2b is a SEM photograph showing the cross section of the surface of the DOC support / ceramic filter coated with the mixed catalyst of the present invention of Preparation Example 1.

Figure 3 shows a schematic diagram of the DOC support / ceramic filter coated with Pt-W / TiO ₂ of Preparation Example 2.

Figure 4a, shows the surface of the support DOC / ceramic filter coating of Preparation Example 2 with Pt-W / TiO ₂ by SEM photograph. Figure 4b, shows the cross section of the surface of the preparation 2 of Pt-W / TiO ₂ with DOC substrate / ceramic filter coated with a SEM picture.

Claims (14)

delete delete delete delete delete delete (1) An oxide of one or two or more metals selected from the group consisting of Ti, Zr, Si, Al, and Ce, with an average particle diameter of 0.1 to 20 μm, and a composite active metal of platinum and tungsten, with an average particle diameter of 0.01 to A first step of preparing a mixture powder by supporting a solution containing 5.0 μm, by mixing an oxide of the metal and the composite active metal in a weight ratio of 10 to 90:90 to 10; (2) a second step of drying and firing the mixture powder to obtain a catalyst powder; And (3) the catalyst powder is any one selected from the group consisting of (i) beta-zeolite, (ii) alumina, titania and silicon, and is 0.5 to 5% by weight of the total weight of the mixed catalyst for the exhaust gas reducing device of a diesel vehicle. A third step of obtaining a mixed catalyst for an exhaust gas reducing device of a diesel vehicle by mixing with an inorganic binder and (iii) a dispersant, characterized in that it is water or alcohol; Method for producing a mixed catalyst for exhaust gas reduction device of a diesel vehicle comprising a. delete delete delete delete delete The method of claim 7, wherein The drying is carried out in an air atmosphere at 105 ℃ for 12 hours, The firing is carried out in an air atmosphere of 550 ℃ method for producing a mixed catalyst for the exhaust gas reducing device of a diesel vehicle. 8. The method of claim 7, wherein the average particle diameter of the oxide of the metal is larger than the average particle diameter of the composite active metal.

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