A method of making the catalyst

 

(57) Abstract:

Use: for cleaning exhaust gases in industry and transport. The inventive method includes the steps of primechanie layer with thickness of 0.1-1.5 mm metal powder with particle size of 10-200 μm to media of a given configuration in a vacuum or protective atmosphere in 0,7-0,85 melting point metal within 1-5 h, layer-by-layer (2-5 layers) coating of aluminum oxide when 723-923 To aqueous polymer-containing (0.1 to 1 wt.) solutions of aluminium salts (5-10 wt.) by spatialize with intermediate drying of the layers within 1-5 min at 373-393 K and further fired at 873-1073 To within 0.5-5 h, the deposition of layers of catalyst from aqueous salt solutions (0.1 to 10 wt%) containing water-soluble polymer (0.1 to 1 wt.) with their final firing in air at 873-1173 To 0.5-5 hours 1 C. p. F.-ly, 2 tab.

The invention relates to catalytic materials and can be used for ecological purposes for flue gas cleaning in industry and transport from carbon monoxide, oxides of nitrogen and hydrocarbons.

There are ways to obtain catalysts which can be used as cathodes sealed-off CO2lasers for gas purification, naprimer oxide with perovskite structure includes the steps of synthesis of the original substance in powder form, its molding, sintering for workpieces strength and machining the working surface.

Closest to the proposed method is a technical solution aimed at obtaining catalytic films based complex oxide of the composition of La1-xSrxCOO3with perovskite structure described in article Ostroushko A. A. and others (Ukr. norgan. chemistry, 1991, T. 36, No. 1, S. 6-9 Catalytic coating was applied to the metal substrate of Nickel or titanium, preheated to 450aboutC. For layering films used an aqueous solution of nitrates of the respective metals containing 0.43 mol/l salt components in the calculation of La1-xSrxCoO3and additives are water-soluble polymers. The firing of the coatings was carried out at 650-900aboutWith over 1.5 to 8 o'clock

The disadvantage of these methods is the low effective surface of the catalyst, which reduces the contact area of the cleaned gases from the active catalytic centers and the degree of purification of these gases.

The aim of the invention is to increase the effective surface area of the catalyst. This goal is achieved by the fact that the metal nosite μm, for example, Nickel or titanium, alternately on each side of the carrier. Before primechanie ferromagnetic metal powders media with freely poured a layer of lead powder in a reciprocating movement in a horizontal plane so that it at least 2 times passes at a speed of not more than 510-2n/s through a region of constant magnetic field of not less than 8000 a/m, and the vector direction of the magnetic field in this region mainly vertically. Primechanie metal powder to the carrier is performed in a vacuum with a residual pressure of not more than 1,310-1PA or inert gas at a temperature of 0,7-0,85 T, where T is the melting temperature of the metal powder in Kelvin, for 1-5 hours At the resulting billet, heated to 723-923 To cause an aqueous solution of aluminium nitrate with a concentration of 5-10 wt. also containing water-soluble polymer in an amount of 0.1-1 wt. Dealing thus 2-5 layers with intermediate drying for 1-5 min at 373-393 K. Then spend OBGYN when 873-1075 To within 0.5-5 h in air. Further heated to 673-723 To the workpiece is applied an aqueous solution containing 0.1-10 wt. salts of metal complex oxide with structure is changed to air at 873-1073 To within 0.5-5 hours

P R I m e R 1. Nickel sheet 0.2 mm thick fill layer of Nickel powder particle size 10-45 μm, a thickness of 0.1 mm, spend processing in a magnetic field, whereby the sheet or tape moving the reciprocating speed of 5 cm/s, walking 2 times through the region of constant magnetic field, and in the zone covering the entire width of the sheet and having along the direction of movement of the sheet, the smaller the length, the magnetic field intensity vector is almost perpendicular to the plane of the sheet, and the magnetic field strength is 8000 A/m, the resulting layer is pressed to the sheet in argon at 1467 (0,85 Tthe PlavaNickel) for 1 h and Then repeat the application of the metal powder on the other side. The obtained workpiece at 923 To put five layers of film by sputtering technique and pyrolysis of an aqueous solution containing 10 wt. of aluminium nitrate, 0.1 wt. polyvinyl alcohol with a preliminary drying layers 378 To within one minute. The solution is applied to the other side of the carrier, followed by calcination at 1073 K for 0.5 h After application sublayer of aluminum oxide applied to a preheated 673 To the substrate 10 layers of film by the sputtering technique (pyrolysis) of an aqueous solution containing 0.1 wt. nitrates the em complex oxide of La0,7Srfor 0.3CoO3. The workpiece after spraying of the solution on the opposite side is placed in a furnace and heated in air up to 930 To aged within 1 h

P R I m m e R 2. Titanium sheet 2 mm thick fill layer of titanium powder with particle size of 200 μm thickness of 1.5 mm and pressed it to the sheet in a vacuum furnace with a residual pressure 1,010-1PA at 1357 (0.7 Tplvl.titanium) for 5 hours On the thus obtained substrate heated to 723 K, put two layers of film by sputtering technique and pyrolysis of an aqueous solution of aluminum nitrate containing 5 wt. this salt and 1 wt. polyvinylpyrrolidone. After applying two layers with intermediate drying at 373 K for each layer within 5 min conducting calcination at 973 K for 5 h Film of catalyst was prepared similar to the first example, putting in four layers on a heated to 723 To the substrate solution containing 5 wt. acetates of lanthanum, strontium, cobalt and Nickel, 1 wt. polyvinylpyrrolidone. The firing is carried out at 1173 K for 0.5 h the catalyst composition La0,7Srfor 0.3Co0,96Ni0,04O3-y.

P R I m e R 3. The substrate get propeca Nickel powder particle size of 50-100 μm layer thickness of 0.5 mm to Nickel sheet with a thickness of 0.8 mm at him spend processing in a magnetic field of a sheet filled with powder, when he goes through a constant magnetic field of 10000 a/m 10 times at a speed of 2 cm/s Spray an 8% aqueous solution of aluminum nitrate containing 0.5 wt. polyvinyl alcohol is carried out in 4 layers on a substrate heated to 823 K. the temperature of the intermediate drying 393 K, 2 minutes. The firing is carried out at 873 K for 2 hours a working solution for deposition of a film of a catalyst containing 10 wt. salts of lanthanum, strontium, cobalt, 0.5. polyvinyl alcohol, it is applied in 2 layers at 623 K. the Annealing of the film is carried out at 873 K for 5 h in air.

The resulting catalyst composition La0,75Srof 0.25CoO3-y.

P R I m e R 4. The catalyst was prepared analogously to example 3, using for applying the intermediate layer instead of nitrate, aluminum acetate aluminum. The resulting catalyst composition La0,7Srfor 0.3Co O3-y.

Selection as an integral part of the intermediate layer of metal powders helps to ensure good adhesion between the base and the catalyst layer, and also allows you to increase the effective surface of the catalyst, since the powder particles are sintered between themselves only at certain points, forming a porous structure with the developed surface of the tailors channels. Without applying a layer of metal powder these channels are not available, and without alumina lack of effective catalyst surface.

Data on the specific surface area of catalysts are given in table. 1.

The particle size of the powder is selected based on the fact that less than 10 μm, the particles are sintered intensively and do not give high surface larger than 200 microns do not have good adhesion and also reduce the number of transport channels. The thickness of the layer of powder is also selected based on the optimal ratio of the catalyst surface and its adhesion to the media.

Temperature and time primechanie metal powders limited from below by the need to ensure the mechanical strength of the catalyst and adhesion of the powder to the metal base that is not provided at temperatures below 0.7 of the melting temperature of the metal powder and the time less than 1 hour higher than 0,85 melting point metal, the temperature and time more than 5 hours leads to excessive compaction of the powder and reduce its surface. Primechanie in vacuum or inert gas is performed to prevent a strong oxidation of metal powders and foundations. In this case the residual pressure should the as sublayer increases the surface of the catalyst (see table). Temperature 723-923 To, which heats the substrate when applying selected based on the fact that at lower temperatures the working solution is not fixed on the substrate, the temperature of 923 K sufficient for decomposition of the salt, and higher temperatures lead to poor quality films and additional energy consumption, make the process less technological. The temperature and time of the intermediate drying is chosen in such a way as to increase the adhesion of the film to the substrate. The number of layers from 2 to 5 selected to receive the next layer of the catalyst of good quality, a certain thickness and a maximum surface. The concentration of working solutions for the deposition of aluminium oxide selected based on the fact that a lower concentration of salt and polymer lower covering ability, require an additional increase in the number of cycles of application, not technological. The same applies to the choice of solution concentration when applying the actual catalyst. Higher concentrations impede uniform spraying of the solutions to the media. The polymer acts as the foaming agent. The temperature and time of annealing after deposition of the aluminum oxide must provide the coating with a maximum pout surface.

Processing in a constant magnetic field of a certain intensity and with a certain orientation of the media covered by a layer of ferromagnetic powders by reciprocating motion allows to obtain more uniform the thickness of the powder layer and to form therein a fibrous structure, which is stored and fixed in primechanie, which increases the area of contact of the catalyst with the gas stream. The field strength is selected based on the fact that the lower tension does not create the right texture, and the minimum number of passes and speed of the reciprocating movement is set for optimal formation of the fibrous structure and levelling layer of powder.

The surface of the catalyst are given per 1 m2the surface of the carrier (base).

The proposed method can be obtained oxide and complicated oxide catalysts for a wide range of compositions and structural types.

Test data showed that obtained as described in examples 1-4 catalysts have similar characteristics, and their applicability for purification of exhaust gases can be illustrated by the table. 2.

1. A METHOD of MANUFACTURING the CATALYSIS is authorized configuration layering at 623 723 To an aqueous solution containing 0.1 to 10 wt. metal complex oxide in the form of salts, water-soluble polymer, calcination at 873 1173 K for 0.5 to 5 hours, wherein the pre-receive intermediate layer representing a combination of metal powder, such as titanium, Nickel, and aluminum oxide, the first metal powder with particle size of 10 to 200 μm is applied in the form of freely poured a layer thickness of 0.1 to 1.5 mm, alternately on each side of the carrier and pressed for 1 5 h in vacuum with a residual pressure of not more than 1.3 10-1PA or inert gas at a temperature of 0.7 to 0.85 melting point of the respective metal powder in degrees Kelvin, then the medium is heated to 723 923 K, the sputtering technique is applied an aqueous solution containing a salt of aluminum in an amount of 5 to 10 wt. and 0.1 to 1 wt. water-soluble polymer, after the application of 2 to 5 layers with intermediate drying for 1 5 min in air at 373 393 To carry out the calcination at 873 1073 K for 0.5 - 5 h in air, for the application of the catalyst in the decaying solutions of salts of the components of complex oxide content of water-soluble polymer charge of 0.1 to 1.0 wt.

2. The method according to p. 1, characterized in that avodat in a reciprocating movement in a horizontal plane so it is at least 2 times passes at a rate not exceeding 5 10-2m/s through a region of constant magnetic field of not less than 8000 a/m, and the vector direction of the magnetic field in this region mainly vertically.

 

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EFFECT: the invention ensures high activity, selectivity and stability of the catalyst to thermocycles at its use in two-stage catalytic system with a decreased loading of platinoid screens.

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1 tbl, 3 ex

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