A method of manufacturing a catalyst, and the catalyst produced in this way

 

(57) Abstract:

The invention relates to a method of manufacturing a catalyst with a catalytically active mass on the body of the carrier by thermal spraying, and the catalyst produced in this way. This provides a thermally sprayed sprayed material containing reactive precursor of at least one of the components of the catalytically active mass on the body of the media and expose the reactive precursor conversion for forming components. Thus there can be produced a catalyst with high determined by the BET method specific surface area. At the same time you can avoid inactivation of heat-sensitive components during the coating process. 2 C. and 17 C.p., 1 Il., table 2.

The invention relates to a method of manufacturing a catalyst with catalytic active mass on the body of the carrier by thermal spraying, and the catalyst produced in this way.

From US 3271326 known mainly Nickel-containing catalyst in which the catalytically active surface put flame spraying. In the first working operation on the pre-made mechanical the temporary coating. After that, the second working operation on the thus pre-treated carrier structure is applied flame deposition of catalytically active components. The peculiarity of this complex method of manufacture is that the deposited catalytically active components are heated to their melting temperature.

From DE 3813312 A1 is known a modified application of the catalytically active components as additives titanium dioxide on the metal structure by thermal spraying. When the catalytically active components are briefly melted and fused to each other when cooled in the places of contact. Thus, it is held by the adhesion of the catalytically active surface.

However, it is known that the catalytic activity of titanium dioxide is very much dependent on the proportion of titanium dioxide, which is present in the anatase modification. The anatase modification of titanium dioxide has the property that favour due to high temperatures irreversibly become less active rutile modification. The germ of titanium dioxide in the rutile modification grow further with the input of heat in cristallina material, which contains a thermally sensitive component, such as titanium dioxide in the anatase modification, the low-melting component. The melting point of the low melting components laying at this lower temperature inactivation, above which irreversibly decreases due, for example, chemical changes in the proportion of thermally sensitive components. During thermal spraying, the sputtered material is heated only to a temperature of melting the low-melting components, thereby inactivation of thermally sensitive components is excluded. The adhesion of the components of the sprayed material between them occurs during thermal spraying by wrapping and melting the low-melting components, thus also in the presence of thermally sensitive components by thermal spraying can be obtained surface with high catalytic activity.

Wrap the catalytically active components of the low-melting component reduces, however, the specific surface area or specific surface area, determined by BET method (brunauer, Emmett and teller) caused mass. For high catalytic activity should be increased accordingly that is littlest spraying can then easily lead to thermal distortion of the body of the carrier or, respectively, the structure of the media. The method is therefore only suitable for thicknesses of the structures of the carrier is greater than about 3 mm

The basis of the invention is the task of the path, as by the method of thermal spraying may be made of a catalyst with a catalytically active mass on the body of the carrier without inactivation of heat sensitive components, and the catalytically active mass in comparison with the prior art has a significantly higher specific surface area, determined by BET method. In addition, the object of the invention is to specify a catalyst produced in this way.

Regarding the manufacturing method for a catalyst with a catalytically active mass on the body of the carrier task is solved according to the invention due to the fact that the body of the carrier is thermally sprayed reactive precursor of at least one of the components of the catalytically active mass and reactive precursor transform for forming components.

The invention thus proceeds from the reasoning, just opposite the corresponding opinion of the expert, to choose for the sprayed material is not the same composition as for the catalytically active mass to be applied on the body wear is beraut reactive precursor, which transform for forming components. Thus, for example, for thermally sensitive components, such as titanium dioxide, can be avoided inactivation conducive to the increase of temperature during the coating process. The fact that component is converted from reactive predecessor only during or after the coating process, and consequently, due to the temperature increase occurring prior to conversion, to inaktivirovanie can't.

It turned out that manufactured by the method according to the invention the catalytically active mass has a high determined by the BET method specific surface area of from 50 to 70 m2/, Extensive research suggests that when converting reactive predecessor knotted chemical bonds, which lead to the formation associated with each other microcrystallites. This cluster of related microcrystallites has a high specific surface area. Due to the high determined by the BET method specific surface area can be significantly reduced thickness of the layer of catalytically active mass in comparison with the prior art with the same high catalytic activity. Due to related baleela with thick thermal warpage. With such a material saving can be accordingly reduced the cost of production. As the body of the carrier is suitable metallic or ceramic body of any shape, for example, in the form of plate, strip, rod or tube. You can also imagine the use for the body of the carrier of other material than metal or ceramic, if it can not be damaged due to high temperature during the coating process.

Especially preferred is when the transformation or chemical reaction of the reactive precursor occurs by thermal activation during spraying. The sprayed material during thermal spraying heated to a temperature above the respective activation temperature above which starts a chemical reaction predecessor.

Thermal activation of the reactive precursor may, however, also be carried out after the deposition due to the heat treatment applied catalytically active mass or body of the carrier above the activation temperature. Such heat treatment may also include the process of calcination.

As a reactive precursor that is converted with the a or bearing a hydroxyl group of compound (gidroksosoedinenii) metal. Salt of the metal or ionic compound of the corresponding metal can be ionized by the appropriate introduction of heat into the cation and anion. This ionization takes place, for example, in each flame. If the temperature during thermal spraying, which here should be understood as plasma spraying and flame spraying is selected correspondingly high, the free metal ion may react with gas molecules surrounding atmosphere and, for example, to form with the oxygen of the metal oxide as the desired components. Under hydroxidealuminum metal here should be understood not yet fully dehydrated, i.e. still containing OH-groups of the oxide compound of the metal. Such connections can easily be thermally transferred, if necessary, with repeated removal of the water, into the corresponding oxide. Thus, gidroksosoedinenii metal can be converted respectively by the selected temperature during deposition of the metal oxide.

Especially preferred is when the metal salt used oxalate, nitrate or carbonate. Such a salt of the metal may be ionized particularly easy, assets aluminum hydroxide, preferably gibbsite (monoclinic-Al(OH)3) or boehmite (trombichesky crystalline Metagalaxy-AlO(OH), or titanium hydroxide, preferably also Metagalaxy titanium TiO(OH)2called metatitanate acid. As aluminum hydroxide, also Metagalaxy titanium can easily, aided by the high temperature, to transfer to the corresponding oxide form. Converted by thermal activation Metagalaxy titanium TiO(OH)2titanium dioxide TiO2is the main constituent of many catalysts. Contains titanium dioxide catalyst is especially suitable for removal of nitrogen oxides using a known DeNOx-how.

Caused by thermal spraying of a catalytically active material has a particularly high determined by the BET method specific surface area, if the use of sprayed material that contains many reactive precursors. For example, the catalytically active components titanium dioxide TiO2as a reactive precursor may be used Metagalaxy titanium TiO(OH)2for aluminum oxide Al2O3boehmite and/or gibbsite, and for other catalytically active component is the heating of the sprayed material during thermal spraying leads to increasing the elimination of water from hydroxycodone. Due to the removal of OH-groups of metatitanate acid and proton of aluminum hydroxide can easily occur tertiary oxide or a mixed oxide of aluminium and titanium. Other reactive precursors ionize and, for example, in oxygen-containing atmosphere is transferred to their oxides. Thus, it can be produced catalytically highly active mass by thermal spraying on the body of the carrier.

As already mentioned, the titanium dioxide can exist as in rutile and anatase modification. Compared with rutile anatase modification modification shows a significantly higher catalytic activity. Crystallization advantageous modification blagopriyatstvuet, if the sprayed material admixed aoademy product. Under zoosadism product understand the sediment chemical element or chemical compound in the presence of substances that are soluble. Aoademy product according to this is respectively mixed with another substance solid chemical element or chemical compound. For example, from a solution that contains the titanylsulphate and paraformat can be obtained titanium dioxide, mixed with tungsten. If this is to be obtained titanium dioxide, crystallized in the anatase modification, and built-in tungsten atoms serve as a blockade for the phase transformation to rutile modification. Other zoosadism product is, for example, crystalline mixture of metatitanate acid and tungstic acid (Ti(OH)2/WO(OH)2). At the relevant soosazhdenie product can be avoided, so that when converting a reactive precursor to the catalytically active component generally appeared a phase transformation at a disadvantage crystalline modification.

For the manufacture of a catalyst containing a metal oxide, it is advantageous if thermal spraying is produced in the atmosphere containing oxygen. In this case, the free metal ion generated by ionization of a salt) combines with oxygen in the metal oxide.

Especially preferred is, if parallel to the sprayed material sprayed metal or metal alloy, the metal or metal alloy and the sprayed material during spraying thoroughly mixed before entering the body of the carrier. The metal or metal alloy acts as described in the introductory part when ozenki flows during the process of spraying the other components and promotes their adhesion to each other and with the body of the carrier. As a metal or metal alloy especially suitable are aluminum and aluminum alloys.

Particularly suitable for thermal spraying is sprayed material in the form of a powder mixture of separate powders with the corresponding average grain size less than 50 microns, preferably less than 10 μm. Before the coating process of the individual powders are intensively mixed. The metal or metal alloy can be well sprayed separately. Through the application of small grain size can be achieved a good conversion of the reactive precursor and increasing the specific method BET specific surface applied catalytically active mass.

Regarding the catalyst problem is solved according to the invention due to the catalyst with a catalytically active mass on the body of the carrier, and the catalytically active mass produced by thermal spraying spraying material on the body of the carrier, and the sprayed material contains a reactive precursor of at least one of the components of the catalytically active mass, and a reactive precursor for the formation of the components was converted before or after spraying.

multinary connection. Under multinary connection here should be understood complex or mixed connection of many components of the catalytically active mass. This connection contributes significantly to the better adhesion of the individual components with each other. If the first reactive precursor is used, for example, vanadium oxalate, and as the second reactive precursor used metatitanate acid during thermal spraying in oxygen-containing atmosphere may occur multiname connection in the form of a mixed metal oxide, which, along with oxygen contains vanadium and titanium.

A particularly preferred catalyst is a catalytically active material has a specific method BET specific surface area of from 40 to 100 m2/g, preferably from 50 to 70 m2/, due to this high specific method BET specific surface high catalytic activity of the catalyst can be achieved with a smaller layer thickness of the catalytically active mass. Since the reduced thickness of the layer of catalytically active mass is associated with a shorter duration of deposition, it is possible to use a carrier with a smaller thickness of no less than 1 mm, preferably less than 100 microns.

The body of the carrier may be made of metal or ceramic. The body of the carrier may have any structure, for example in the form of plate, strip, rod or tube. The body of the medium can also be made in the form of a honeycomb. Especially preferred as the material for the body of the carrier is chrome-aluminum steel. With similar body of the carrier can be achieved high service life of the catalyst.

For better adhesion of the catalytically active mass can be provided that the body of the carrier before applying the catalytically active mass give roughness by mechanical or chemical means.

Examples of carrying out the invention are explained in more detail using the drawing and table. 1,2. In particular, they show:

the drawing is a cross section through the body of the carrier corresponding to the invention of the catalyst components and the catalytically active mass deposited on it by thermal spraying;

table. 1 - select for spraying material for the manufacture of DeNOx-catalyst components with indication of percentage mass content, as well as the corresponding average of pelicansaero, moreover, the above components are taken from table. 1.

For examples that relate to the oxide catalysts with catalytically active components, thermal spraying occurs in the atmosphere containing oxygen. The temperature during thermal spraying is chosen so that thermal activation of the reactive precursor happened to hit on the body of the carrier. As a final operation to produce the calcination caused mass. Thus, there is a full dehydration and reached the final of the oxide structure of the catalytically active mass. As the sprayed material always use a powder blend of separate powders of the respective components. The average grain size of the individual components of the sprayed material can be taken from the table. 1.

Table. 1 shows for spraying material in the form of a powder mixture suitable components for the manufacture of DeNOx-catalyst for reducing oxides of nitrogen in exhaust gas incinerators using a reducing agent such as ammonia.

In table. 1 presents the relative percentages mass components ( aluminium or aluminium alloy, in this case, aluminium and manganese. Mixing with other components occurs before contact with the body of the carrier. The remaining components are mixed in the sprayed material prior to thermal spraying. As a reactive precursor for titanium dioxide, a catalytically active in DeNOxthe catalyst can be applied by selecting metatitanate acid or a mixture of tungstic acid with metatitanate acid in the form of soosazhdenie product. As such soosazhdenie product can also be used dried and calcinated joint precipitate of titanium and tungsten, obtained from containing titanylsulphate and paraformat solution. This aoademy product contains titanium dioxide predominantly in the catalytically active anatase modification, in which the tungsten pending in the interstices of the lattice of titanium dioxide. Adulteration or deposition of tungsten prevents the conversion of titanium dioxide of the anatase modification in unwanted rutile modification.

Table. 2 shows four alternative possibilities for the composition of the sprayed material for the manufacture of DeNOx-catalyst. The corresponding percentage mass content should be taken from tea, usually referred to as AlMn3(example 4) in parallel to a mixture of the remaining components. Thermal activation of the reactive precursor (in this case, boehmite, gibbsite, vanadium oxalate, oxalate tungsten, metalicana acid and aoademy product consisting of a mixture of tungstic acid and metatitanate acid) occurs during thermal spraying. Applied mass is subjected to a calcination process to reach a final dehydration to obtain a catalytically active oxide structure of the deposited mass. All manufactured according to examples 1-4 catalytically active mass have a certain method BET specific surface area of from 60 to 70 m2/,

Due to x-ray analysis proved the advantage of the method according to the invention. If the catalytically active ingredients of titanium dioxide using reactive precursor in the form of metatitanate acid or, respectively, containing metatitanate acid soosazhdenie product, titanium dioxide in the catalytically active mass is predominantly in the anatase modification. Thermal inactivation of the anatase modification due to the transformation into rutile modification can b the tion. The phase transformation to rutile modification does not occur. This, however, otherwise, if the sprayed material using titanium dioxide with tungsten embedded in the interstices of the lattice. Such aoademy product is not reactive precursor in the sense of a method corresponding to the invention. Here there is no conversion.

The drawing shows a cross section made according to example 1 a catalyst to reduce oxides of nitrogen by DeNOx-method. The body of the carrier 1 is chromium-aluminum steel in the form of a plate with a thickness of 40 μm. The catalytically active mass of 10 marked on both sides by thermal spraying. The surface of the body of the carrier 1 in the drawing is not represented in more detail, however, it can be made rough due to mechanical or chemical treatment. Due to the deformation during the collision of the aluminum oxide 2 is held on the body of the carrier 1 due to forces of adhesion. Simultaneously sputtered aluminum 3 acts as a binder and associates as a separate catalytically active components with each other, and the catalytically active mass of 10 on the body of the carrier 1. Around each atomic hydroxy is adiya (V2O5) 5 and tungsten trioxide (WO3) 6. The corresponding catalytically active components 4, 5, 6, and aluminum oxide 2 in addition to the forces of adhesion are held each other due to chemical compounds as a result of the tertiary oxides. Such mixed oxides lead to high resistance to abrasion catalytically active mass 10. It is related to the high service life of such a catalyst.

1. A method of manufacturing a catalyst with a catalytically active mass on the body of the carrier by thermal deposition of sputtered material on the body of the carrier, characterized in that the sprayed material contains reactive precursor, at least one of the components of the catalytically active mass, and as a reactive precursor using a hydroxide of titanium, which is subjected to conversion for forming components.

2. The method according to p. 1, characterized in that as titanium hydroxide use Metagalaxy titanium.

3. The method according to PP.1 and 2, characterized in that the conversion of the reactive precursor is produced by thermal activation during deposition and/or after spraying.

4. The method according to PP.1 to 3, different/P> 5. The method according to PP.1 to 4, characterized in that as a follow-reactive precursor using salt of the metal or gidroksosoedinenii metal.

6. The method according to PP.1 to 5, characterized in that as a follow-reactive precursor using oxalate, nitrate or carbonate.

7. The method according to PP.1 - 6, characterized in that as a follow-reactive precursor used aluminum hydroxide, preferably gibbsite or boehmite.

8. The method according to PP.1 to 7, characterized in that the use of sprayed material containing aoademy product.

9. The method according to PP. 1 to 8, characterized in that use aoademy product containing tungsten or titanium.

10. The method according to PP.1 to 9, characterized in that the reactive precursor is converted into an atmosphere containing oxygen.

11. The method according to PP.1 to 10, characterized in that simultaneously and separately with the sprayed material is thermally sprayed metal or metal alloy, the metal or metal alloy and the sputtered material is thoroughly mixed during the spraying before entering the body of the carrier.

12. The method according to PP.1 - 11, characterized in that simultaneously and separately HP CLASS="ptx2">

13. The method according to PP.1 - 12, characterized in that the sprayed material sprayed powder mixture of separate powders with the corresponding average grain size less than 50 microns, preferably less than 10 microns.

14. The catalyst with a catalytically active mass on the body of the carrier obtained by thermal deposition of sputtered material on the body of the carrier, characterized in that the sprayed material contains reactive precursor, at least one of the components of the catalytically active mass, and a reactive precursor for the formation of components subjected to transformation during and/or after deposition, and as a reactive precursor using a hydroxide of titanium.

15. The catalyst according to p. 14, characterized in that the catalytically active mass contains multinary connection.

16. The catalyst PP. 14-15, wherein the catalytically active mass contains tertiary metal oxide.

17. The catalyst PP. 14-16, characterized in that the catalytically active mass is determined by the BET method specific surface area of from 40 to 100 m2/g, preferably from 50 to 70 m2/,

18. The catalyst PP.14-17, the ex is 19. The catalyst PP. 14 to 18, characterized in that the body of the carrier is made of chromium-aluminum steel.

 

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