Kataliticheski element for the conversion of ammonia

 

(57) Abstract:

The invention relates to a cellular catalytic elements for the conversion of ammonia and can be used in the production of nitrogen, hydrocyanic acid, has synthesis as a catalyst for the second stage. The invention consists in that the catalytic element is designed as a layer of the individual prisms connected by edges without gaps, with cellular channels. What's new is that the diameter of the base of the prism and its height are respectively 4 - 100 and 2 - 75 equivalent diameters cell channel. Additional differences are that the base of the prism has the shape of three-, or four-, or hexagon, and that element is made of material composition, %: Fe2O392; Cr2O38 or Fe2O389,5; ZrO25; MgO 5; ZrBaO 0.5 or Fe2O379; Al2O320; MgO 1 or Fe2O379,7; Al2O320; V2O50.3 or perovskite (O1LaO9MnO3) 90; Al2O38; SiO22. The technical result consists in increasing thermal durability and service life of the catalyst. 2 C.p. f-crystals, 8 ill.

Now the present invention relates to a cellular ka is the first and hydrocyanic acid, and has synthesis, for example, as a catalyst for the second stage.

Known two-stage catalytic system, in which the first step is a layer of platinum mesh, and the second step layer replacenode oxide catalyst made of different material compositions. Layer replacenode oxide catalyst may be in the form of irregularly stacked pellets (tablets), or in the form of layers of honeycomb structure. The disadvantages of the known catalytic systems is that replacenode oxide catalysts have low mechanical and thermal strength, or decreased activity or increased hydraulic resistance (SU 300057, 1973 SU 771958, 1995, US 4812300, 1989, GB 1236819, 1971, GB 1364001, 1974).

The closest to the essence and the achieved result to the proposed technical solution is a catalytic element for the conversion of ammonia based replacenode oxide catalyst made in the form of a layer of the individual prisms connected by edges without gaps, and having a cell channels (EP 0260704, 1988). (Prism is a polyhedron, two faces (bases) - equal polygons located in computers is lopidine dictionary, M: Soviet encyclopedia, 1987, S. 1059).

The main drawback of the prototype is small thermal durability and service life of the cell, the catalytic element.

The technical result for the solution of which is directed present the alleged invention, is a significant increase in thermal durability and service life of the cell catalytic element for the conversion of ammonia.

The technical result is achieved by the catalytic element for the conversion of ammonia based replacenode oxide catalyst made in the form of a layer of the individual prisms connected by edges without gaps, with cellular channels, according to the invention 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 (Equivalent to the diameter of a well-known concept in hydrodynamics, it is four squares (base channel) divided by the perimeter of this square - see the tutorial A., Kasatkin "Basic processes and apparatus of chemical technology", M.: Chemistry, 1973, S. 37).

Additional differences are that the base of the prism are in the form of three-, or four-, or Shestopal 92; Cr2O38 or Fe2O389,5; ZrO25; MgO 5; ZrBaO 0.5 or Fe2O379; Al2O320; MgO 1 or Fe2O379,7; Al2O320; V2O50.3 or perovskite (CaO1LaO9MnO3) 90; Al2O38; SiO22.

In Fig. 1 is placed in the reactor vessel of the proposed cell catalytic element for the conversion of ammonia, a side view, in longitudinal section; Fig. 2 a is shown in the top on this catalytic element made of prisms, with the base, respectively, three-, or four-, or hexagon, Fig.3 a-b shows a perspective view of three separate prisms, having a basis of three-, or four-, or hexagon, Fig.4 practically repeats Fig.1 with the difference that cell catalytic element is depicted a layer of platinum catalyst grids, which is the catalyst for the first stage.

The proposed cell catalytic element is placed in the reactor vessel 1 on the supporting device 2 and is made in the form of layer 3 of the individual prisms or 4 or 5 or 6, the stacked side faces 7 with no gaps. Prism provided through mobile channels 8 and can be the basis of any triangle prism 4, or even the higher four squares of its base divided by the perimeter of its base. For prisms, having a basis of a correct three-, four - and hexagon, these diameters are respectively equal to D3 = 0,577 And D4 = 1A and D6 = 1,732 A, where a is the side length of the correct three-, or four - or hexagon at the base of the prism (see Fig. 3 a-C). The equivalent diameter of the base of the prism Di (where i = 3, 4, 6) and its height H are respectively 4 - 100 and 2 - 75 equivalent diameters cell channel 8, which is calculated in a similar manner, namely: d = 4S/P, where S and P are the area and perimeter of the cross section of the cellular channel. The catalytic element is made from a material having one of the following composition, %: Fe2O392; Cr2O38 or Fe2O389,5; ZrO25; MgO 5; ZrBaO 0.5 or Fe2O379; Al2O320; MgO 1 or Fe2O379,7; Al2O320; V2O50.3 or perovskite (CaO1LaO39MnO2) 90; Al2O38; SiO22.

In the case of the proposed cell catalytic element as a catalyst for the conversion of ammonia to the second stage on top of it there is a layer of platinum nets 9 (see Fig.4), which is the catalyst for the first stage.

Cell rolled the way.

A gas mixture containing ammonia and oxygen-containing gas enters the reactor vessel 1 and moving it downwards (see arrow in Fig.1), passes through cell channels 8 prisms or 4 or 5 or 6 cell catalytic element 3. On the inner surfaces of the cell channels 8 is the catalytic conversion of ammonia to the target product. The target products are as follows:

in the manufacture of nitric acid and has synthesis - NO;

- in the production of hydrogen cyanide is HCN.

Resulting from the conversion of ammonia gas mixture containing the target product, through supporting device 2 out of the reactor 1. If the proposed cell catalytic element is used as a catalyst for the conversion of ammonia to second stage i.e. when the first step along the gas mixture layer is a platinum catalytic grids, cell catalytic element works as described above but with the difference that the source gas mixture passes through the platinum nets 9 (see Fig.4).

Example. To prove the greatest benefit we offer the above intervals is equivalent to the diameter of osnovaniya nitrogen and hydrocyanic acid, and has synthesis. In the manufacture of nitric acid used reactor with a working diameter 1650 mm, working under an absolute pressure of 0.6 MPa. The source of the ammonia-air mixture with a concentration of NH310% passed through a two-stage catalytic element, operating at a temperature of 900oC, with an average operating speed is calculated for the cross section of the reactor, 5 m/s as the catalyst of the first stage used a grid layer of the composition of the Pt - 81, Pd - 15, Rh - 3,5, EN - 0,5%. As the catalyst of the second stage used cell catalytic elements in the form of a layer of prisms with the base of the triangle is made from a material composition of Fe2O3- 92 and Cr2O3- 8%. The equivalent diameter of the base of the prism was 10 equivalent diameters cell channel, and the height of the prism - 8 equivalent diameters cell channel. After the catalyst mixture contained NO, H2O, O2and N2in widely known for the production concentrations.

In the production of hydrocyanic acid was applied to the reactor with a working diameter of 1200 mm, operating under atmospheric pressure. As the source gas mixture used a mixture of the following composition: NH3- 11, CH4- SUB> TO 0.3, CH4TO 0.5, H2TO-7.6, H2O - 23,1, O2- 0.1% and N2- the rest; the temperature of the catalytic system 1030oC. the Gas mixture was passed through a two-stage catalytic element with an average operating speed is calculated for the cross section of the reactor, 9 m/s as the first stage used a grid layer of the alloy Pt - 92,5 and Rh - 7.5%, in the second stage used a layer of prisms with the base in the form of a rectangle made from a material composition of Fe2O3- 79,7, Al2O3- 20 and V2O5to 0.3%. The equivalent diameter of the base of the prism was 50 equivalent diameters cell channel, and the height of the prism - 15 equivalent diameters cell channel.

Production has synthesis used a reactor with a working diameter 2800 mm working under an absolute pressure of 0.14 MPa. As the source gas mixture used a mixture of the following composition: NH3- 14,2, H2O - 66,2, O2- 19,1% and N20,5 vol.%. The composition of the gas after the catalytic system of NH3- 0,6, NO - 13, H2O - 83,2, O2- 2.7 and N2- 0,5%; the temperature of the catalytic system 925oC. the Gas mixture was passed through a two-stage catalytic element with the average operating isator of the same composition, as with the previous tests in the production of hydrocyanic acid. As the catalyst of the second stage used cell catalytic element in the form of a layer of prisms with the base in the form of a hexagon is made from a material composition of Fe2O379, Al2O320 and MgO - 1%. The equivalent diameter of the base of the prism was 88 equivalent diameters cell channel, and the height of the prism - 18 equivalent diameters cell channel.

As a result of tests it is established that cell catalytic elements for the conversion of ammonia made of prisms having proposed the relative geometrical parameters, have a lifespan of at least 2.5 - 3 years and can withstand 40 - 45 thermal cycles from ambient temperature at a stopped reactor to operating temperature in the reactor in the nitrogen production, hydrocyanic acid and has synthesis, respectively, 900, 925 1030 andoC). Cell catalytic elements for the conversion of ammonia made of prisms having a relative geometrical parameters for the proposed claims intervals, have a lifespan of less to 1.27 - 1.59 times and incubated for 30 thermal cycles.

1. The catalytic element is s prisms, the United side edges without gaps, and having a cell channels, wherein the equivalent diameter of the base of the prism and its height are respectively 4 - 100 and 2 - 75 equivalent diameters cell channel.

2. Item under item 1, characterized in that the base of the prism has the shape of three-, or four-, or hexagon.

3. Element according to any one of paragraphs.1 and 2, characterized in that it is made from a material having one of the following composition, %: Fe2O392; Cr2O38% or Fe2O389,5; ZrO25; MgO 5; ZrBaO 0.5 or Fe2O379; Al2O320; MgO 1 or Fe2O379,7; Al2O320; V2O50.3 or perovskite (CaO1LaO9MnO3) 90; Al2O38; SiO22.

 

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FIELD: production of honeycomb substrates for catalyst converters for two-wheeled or diesel vehicles.

SUBSTANCE: the invention is dealt with production of honeycomb substrates made out metal sheets piled or rolled in a package and minimized to the honeycomb elements used first of all as honeycomb substrates for catalyst converters in the systems of exhaust gas (EG) neutralization. There is a description of a honeycomb element (1) first of all as a honeycomb substrate for a catalyst converter for systems of two-wheeled vehicles exhaust gas neutralization. The honeycomb substrate for catalyst converter consists of some layers of metal sheets (2, 3) packed as a package or minimized in a roll, which are at least on separate sections are structured or profiled in such a manner, that they form for EG flowing channels (4). At that the metal sheets (2, 3) represent the sheets of high-quality steel of more than 0.08 mm thick with a share of aluminum from 6 up to 12 mass % multiplied by 0.02 mm and divide by "d" - thickness of the metal sheets (2, 3). The technical result - a possibility to use metal sheets depending on the share of aluminum in them and their thickness, that allows to use the sheets taken from production process of manufacture of a material subjected to a hot aluminization.

EFFECT: the invention ensures a possibility to use metal sheets for the purpose depending on the share of aluminum in them and their thickness.

5 cl, 1 dwg

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