Catalytic element for heterogeneous high-temperature reactions

FIELD: inorganic synthesis catalysts.

SUBSTANCE: invention relates to catalytic elements including ceramic contact of regular honeycomb structure for heterogeneous high-temperature reactions, e.g. ammonia conversion, and can be used in production of nitric acid, hydrocyanic acid, and hydroxylamine sulfate. Described is catalytic element for heterogeneous high-temperature reactions comprising two-step catalytic system consisting of ceramic contact of regular honeycomb structure made in the form of at least one bed constituted by (i) separate prisms with honeycomb canals connected by side faces with gap and (ii) platinoid grids, ratio of diameter of unit honeycomb canal to diameter of wire, from which platinoid grids are made, being below 20.

EFFECT: increased degree of conversion and degree of trapping of platinum, and prolonged lifetime of grids.

5 cl, 6 ex

 

The invention relates to catalytic elements including ceramic contact regular cell structure for high-temperature heterogeneous reactions, for example for the conversion of ammonia, and can be used in the production of nitrogen, hydrocyanic acid, has synthesis.

Known cell catalytic element (Patent RF №2128081, IPC6B01J 35/04, SW 21/26, 1999), which is placed in the reactor vessel for supporting the device in a layer of the individual prisms of the coupled side edges without gaps. This is equivalent to the diameter of the base of the prism and its height are respectively 4-100 and 2-75 equivalent diameters cell channel. In case of using a catalytic element as a catalyst for the conversion of ammonia to the second stage on top of it have a layer of platinum mesh, which is the catalyst for the first stage.

The disadvantage of the catalytic element of the second stage is not sufficiently high conversion in the oxidation of ammonia, oxidative ammonolysis of natural gas

There is a method of conversion of ammonia (RF Patent No. 2223217, IPC7SW 21/26, 2004), including the transmission of the reaction gas mixture through a two-stage catalytic system consisting of a layer of inert nozzles cell structure, the first stage in the form of the platinum layer nets the second stage in the form of a layer of catalyst a regular cell structure. Moreover, the ratio of the equivalent diameter of the channel of the catalyst to the equivalent diameter of the channel inert nozzle is (0,9-1,3):1, the ratio between their open surfaces equal to (0,7-1,2):1.

The disadvantage is not high enough conversion in the oxidation of ammonia and oxidative ammonolysis of natural gas.

The closest technical solution is a catalytic element of the regular cell structure for high-temperature heterogeneous reactions (RF Patent No. 2209117, IPC701J 35/04, 23/745, 23/26, 21/04, SW 21/26, 2003), made in the form of a layer of the individual prisms connected side faces and having a cellular channels, separate prisms when laying them in a layer of the honeycomb structure have a gap between the side faces of 0.1 to 1.0 diameter cell channel.

The disadvantage of this solution is the same as in previous decisions, not high enough conversion in the oxidation of ammonia and oxidative ammonolysis of natural gas.

The problem solved by the present invention is the creation of a catalytic element for high-temperature heterogeneous reactions that reduce the amount of the platinum mesh and increasing the conversion rate of ammonia oxidation to nitric oxide and increasing the conversion rate in the oxidative ammonolysis of natural gas.

The problem is solved using rolled the practical element for high-temperature heterogeneous reactions includes two-stage catalytic system consisting of ceramic contact regular cellular structure made in the form of at least one layer of the individual prisms with cellular channels connected side faces with a gap, and the platinum mesh. The ratio of the diameter of a single cell channel to the diameter of the wire from which made the platinum mesh, has a value less than 20.

A catalytic element for high-temperature heterogeneous reactions preferably has a ceramic contact regular cellular structure, which is made of a material containing porous mullite more than 85 wt.%.

A catalytic element for high-temperature heterogeneous reactions preferably has a ceramic contact regular cell structure, which has the density of mobile channels, which open surface of the ceramic contact does not exceed 30%.

A catalytic element for high-temperature heterogeneous reactions preferably has a gap between the individual prisms more of the diameter of a single cell channel.

A catalytic element for high-temperature heterogeneous reactions preferably contains at least one layer block cordierite sorbent, which come under the layers of ceramic regular contact is th cell structure.

A catalytic element for high-temperature heterogeneous reactions preferably contains under the platinum mesh package woven nets - traps platinum.

A catalytic element for high-temperature heterogeneous reactions preferably has a ceramic contact regular cell structure with a layer height of not more than 10 diameters of the single cell channel.

In the proposed solution to achieve the objectives proposed catalytic element for high-temperature heterogeneous reactions, such as conversion of ammonia, which has a ceramic contact regular cellular structure made in the form of one or more layers of flat prisms having a cylindrical cell channels, separate prisms when laying them in a layer of honeycomb structure are preferably (but the gap can be smaller and to be 0.1-1.0 cell diameter of the channel, depending on the material of the ceramic contact gap of more than one cell diameter of the channel. The height of the flat prism depends on the diameter of the cell channel and preferably not greater than 10 diameters of the single cell channel. The number of flat faces of the prisms varies from three to six. When this side of the base of the prism does not exceed 150 mm Mutually parallel cylindrical channels, subsequently is camping in a checkerboard pattern, create a regular cell structure, the density of the channels should provide an exposed surface of not more than 30%. The diameter of the single cell channel is selected so that the ratio of channel diameter to the diameter of the wire from which are woven or braided mesh, had a value of less than 20. Flat ceramic prisms regular honeycomb structure made of aluminosilicate materials and have a melting point not less than S°. The presence of the material more than 85% of highly porous mullite ceramics gives high resistance to sudden temperature changes in the area of 1000°and provides a warranty period of operation of these products is not less than 10000 hours. To make ceramic prisms catalytic activity in the oxidation of ammonia in the ceramic composition comprises up to 15% of the oxides of copper, silver, cobalt, iron, and in the production of HCN to 0.2% of platinum and palladium. For laying a layer around the perimeter of the contact device are truncated under the diameter of the contact apparatus prism triangular and trapezoidal forms.

In order to reduce losses of platinum oxidation of ammonia is preferably carried out with nets for the capture of platinum and/or cellular ceramic sorbent.

The following examples illustrate the proposed solution

Example 1

In the contact device UKL-7 is and grates stack distribution grid from heat-resistant steel, the layer of ceramic contact regular cell structure from a single rectangular prism with a height of 14 mm and the sides of the base 105×95 mm with a gap of 1.5 mm between the prisms and composition, wt.%: Fe2About3- 8, CuO - 3, the rest of the mullite. For dolldivine around the perimeter of the layer of catalyst blocks are used that have a triangular shape with convex hypotenuse. The radius of convexity of the hypotenuse is 800 mm Diameter single cell channel is 1.4 mm on Top of the catalyst - ceramic prisms - stack package of nine standard woven platinum mesh alloy Plygrd-4-3,5. Wire diameter 0,092 mm diameter single cell channel to the diameter of the wire, which made the platinum mesh is 15,21. The open surface of the ceramic contact regular basis structure is 29%. The operating temperature of the contact apparatus 900-910°C. the Concentration of ammonia in the ABC of 11.5%. The conversion of ammonia to NO 95.5%. The lifetime of the catalytic system 5700 including Irrecoverable losses platinum - 0,129 g/T. the Number of destroyed prisms contact regular cell structure does not exceed 1% of the total number of loaded prisms.

Example 2

In the reactor for the synthesis of hydrogen cyanide stack separating the grid from heat-resistant steel, on which is placed a layer of ceramic contactaremos cellular structure of unit prisms in the form of parallelepipedal height 14 mm, the base is a square with a side of 100 mm, the diameter of the cell channel to 1.4 mm. In aluminosilicate composition of the prisms is 0.2% of platinum. The content in the ceramic phase of mullite 90%. thermal gap between the blocks is 1.5 mm For dolldivine around the perimeter of the layer of catalyst - ceramic prisms are blocks that have a triangular shape with convex hypotenuse. The radius of convexity of the hypotenuse is 600 mm Further layer of catalyst - ceramic prisms - stack four woven platinum mesh alloy Plygrd-4-3,5. The ratio of the diameter of a single cell channel to the diameter of the wire, which made the platinum mesh is 15,21. The open surface of the ceramic contact regular basis structure is 24%. At the operating temperature of 950-1050°and conversion to ammonia 60-65% of the HCN content at the outlet of the reactor is maintained at a level not less than 7.5% over 2500 hours of continuous operation of the contact device. The degree of destruction of the ceramic contact regular cell structure is 3%.

Example 3

In the contact device UKL-7 on the grate stack distribution grid from heat-resistant steel, the block layer cordierite sorbent from a hexagonal prism with a height of 35 mm, the side of the base 36 mm, side triangular cell channel 5 mm, wall thickness of 0.8 mm, Then through the separation jarosch icuu grid on a layer of sorbent is placed a layer of ceramic contact regular cell structure from a single rectangular prism with a height of 14 mm and the sides of the base 105× 95 mm with a gap of 1.5 mm between the prisms and composition, wt.%: Fe2About3- 8, CuO - 3, Co3O4- 2, the rest of the mullite. The diameter of the single cell channel is 1.4 mm To dolldivine on the perimeter of the contact layer and the sorbent used prism having a triangular shape with convex hypotenuse. The radius of convexity of the hypotenuse is 800 mm on Top of the contact stack package of eight knitted platinum mesh alloy Plygrd-4-3,5. Wire diameter 0,076 mm diameter single cell channel to the diameter of the wire, which made the platinum mesh is 18,42. The open surface of the ceramic contact regular cell structure is 29%. The operating temperature of the contact apparatus 885-900°C. the Concentration of ammonia in the ABC of 10.05%. The conversion of ammonia to NO amounted to 95.7%. The lifetime of the catalytic system 5097 h, irretrievable loss of platinum to 0.127 g/T. the Number of destroyed blocks contact regular cell structure does not exceed 1% of the total number of downloaded blocks sorbent 3%.

Example 4

In the contact device UKL-7 on the grate stack distribution grid from heat-resistant steel, the block layer cordierite sorbent from a hexagonal prism with a height of 25 mm side of base 36 mm, side triangular cell channel 5 mm, wall thickness of 0.8 mm. Forth across the separating heat-resistant mesh on a layer of sorbent is placed a layer of ceramic contact regular cell structure, consisting of a single rectangular prism with a height of 14 mm and the sides of the base 105×95 mm with a gap of 1.5 mm between the prisms and composition, wt.%: Fe2O3- 8, CuO - 3, Co3O4- 2, the rest of the mullite. The diameter of the single cell channel is 1.4 mm To dolldivine on the perimeter of the contact layer and the sorbent used prism having a triangular shape with convex hypotenuse. The radius of convexity of the hypotenuse is 750 mm, Top contact stack package of four woven nets-traps (alloy MPE-5, wire diameter 0,092) and eight knitted platinum mesh alloy Plygrd-4-3,5. Wire diameter 0,092 mm diameter single cell channel to the diameter of the wire, which made the platinum mesh is 15,22. The open surface of the ceramic contact regular basis structure is 29%. The operating temperature of the contact apparatus 850-900°C. the Concentration of ammonia in the ABC of 10.05%. The conversion of ammonia to NO was 96.1%. The lifetime of the catalytic system 3200 h, irretrievable loss of platinum - 0,117 g/T. the Number of destroyed prisms contact regular cell structure does not exceed 0.3% of the total number of downloaded blocks sorbent 3%.

Example 5

In the contact device UKL-7 on the grate stack distribution grid from heat-resistant steel, the block layer Cordy is ricovero sorbent from a hexagonal prism with a height of 25 mm, side of the base 36 mm, side triangular cell channel 5 mm, wall thickness of 0.8 mm, Then through the separating heat-resistant mesh on a layer of sorbent is placed a layer of ceramic cell contact from a single rectangular prism with a height of 10 mm and the sides of the base 85×95 mm with a gap of 1.0 mm between the prisms and composition, wt.%: Fe2O3- 11, CuO - 3, Ag2O - 2, the rest is mullite. The diameter of the single cell channel is 1.1 mm For dolldivine on the perimeter of the contact layer and the sorbent used prism having a triangular shape with convex hypotenuse. The radius of convexity of the hypotenuse is 750 mm, Top contact stack package of four woven nets-traps (alloy MPE-5, wire diameter 0,092) and eight knitted platinum mesh alloy Plygrd-4-3,5. Wire diameter 0,076 mm diameter single cell channel to the diameter of the wire, which made the platinum mesh is 14.5. The open surface of the ceramic contact regular cell structure is 22%. The operating temperature of the contact apparatus 850-900°C. the Concentration of ammonia in the ABC of 10.0%. The conversion of ammonia to NO was 96,4%. The lifetime of the catalytic system 3300 h, irretrievable loss of platinum - 0,092 g/T. the Number of destroyed prisms contact regular cell structure does not exceed 0.2% of the t total number of loaded blocks sorbent 2%.

Example 6 (prototype)

In the contact device UKL-7 on the grate stack distribution grid from heat-resistant steel, the block layer of the catalyst for selective oxidation of ammonia to NO composition, wt.%: Fe2O3- 80-85, Cr2O3- 5-10, binder based on Al2O3- other, having a square cross section. The height of the blocks 50 mm side of the block 70 mm, wall thickness 1.5 mm, the size of the channel 5×5 mm clearance between the side faces 5 mm, which is 1.0 in diameter cell channel. For dolldivine around the perimeter of the layer of catalyst blocks are used that have a triangular shape with convex hypotenuse. The radius of convexity of the hypotenuse is 800 mm Above the catalyst stack package of nine standard platinum mesh. The diameter of the wire from which made the platinum mesh is 0,092 mm diameter single cell channel to the diameter of the wire from which made the platinum mesh is 54,34. The operating temperature of the contact apparatus 900-910°C. the Concentration of ammonia in the ammonia-air mixture of 11.5%. The conversion of ammonia to NO was 93.5%. The lifetime of the catalytic system is not less than 4,000 hours with preservation of normal (1.35 g/t) deadweight loss of platinum. The number of destroyed blocks of the catalyst honeycomb structure is % of the total number of downloaded blocks.

As seen from the above examples, when the ratio of the diameter of a single cell channel to the diameter of the wire from which made the platinum mesh, less than 20 proposed catalytic element shows a high degree of conversion in the oxidation of ammonia to nitric oxide, oxidative ammonolysis of natural gas.

Thus, the technical result of the claimed solution is to increase the degree of conversion in the high-temperature heterogeneous reactions, an increase in the degree of recovery of platinum and lifetime platinum mesh.

1. A catalytic element for high-temperature heterogeneous reactions involving two-stage catalytic system consisting of ceramic contact regular cellular structure made in the form of at least one layer of the individual prisms with cellular channels connected side faces with a gap, and the platinum mesh, characterized in that the ratio of the diameter of a single cell channel to the diameter of the wire from which made the platinum mesh, has a value less than 20.

2. A catalytic element for high-temperature heterogeneous reactions according to claim 1, characterized in that the ceramic contact regular honeycomb structure made of a material containing porous mullite more than 85 wt.%.

3. Catalytica the cue element for high-temperature heterogeneous reactions according to claim 1, characterized in that the ceramic contact regular honeycomb structure has a cell density of the channels in which the open surface of the ceramic contact does not exceed 30%.

4. A catalytic element for high-temperature heterogeneous reactions according to claim 1, characterized in that the gap between the individual prisms is more than diameter of a single cell channel.

5. A catalytic element for high-temperature heterogeneous reactions according to claim 1, characterized in that it further comprises at least one layer block cordierite sorbent.

6. A catalytic element for high-temperature heterogeneous reactions according to claim 1, characterized in that under the platinum nets are installing a package from a woven mesh - traps platinum.

7. A catalytic element for high-temperature heterogeneous reactions according to any one of claims 1 to 6, characterized in that the ceramic contact regular honeycomb structure has a height of layer is not more than 10 diameters of the single cell channel.



 

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7 cl, 68 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for liquid-phase catalytic alkylation of aromatic amines. Method involves alkylation reaction of aromatic amines in the presence of hydrogen and lower alcohols at temperature 50-70°C on a heterogeneous catalyst. The distinctive specificity of method represents alkylation of amine with formaldehyde solution in reactor with reaction zone filled with catalyst consisting of aluminum oxide-base block high-porous cellular carrier with porosity value 7-95%, not less, and palladium as an active component with the mass content = 1.3-2%. As a rule, in the alkylation process catalyst prepared by impregnation of block high-porous cellular carrier with palladium salts treated preliminary in the constant magnetic field is used. Usually, in the case of alkylation of aniline and for preferential synthesis of monomethylaniline the molar ratio aniline to formaldehyde solution = 1.6:(1.1-1.6) is used. Proposed method as compared with the nearest analog in the case of alkylation of aniline provides preparing monomethylaniline mainly, to decrease the content of palladium as an active component in catalyst and to decrease the reaction pressure and hydraulic resistance of catalytic layer also. Invention can be used in producing antiknock additives to motor fuels (gasolines).

EFFECT: improved alkylation method.

3 cl, 4 ex

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