WO2024242593A1 - Système catalytique d'oxydation de l'ammoniac (variantes) et procédé de production - Google Patents

Système catalytique d'oxydation de l'ammoniac (variantes) et procédé de production Download PDF

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Publication number
WO2024242593A1
WO2024242593A1 PCT/RU2024/050104 RU2024050104W WO2024242593A1 WO 2024242593 A1 WO2024242593 A1 WO 2024242593A1 RU 2024050104 W RU2024050104 W RU 2024050104W WO 2024242593 A1 WO2024242593 A1 WO 2024242593A1
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activated
platinum
rhodium
alloy
mesh
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Russian (ru)
Inventor
Павел ХОРИКОВ
Григорий СИВКОВ
Александр ДЮКОВ
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Open Joint Stock Co "krasnoyarskiy Zavod Tsvetnykh Metallov Imeni VN Gulidova" "krastsvetmet" Jsc
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Open Joint Stock Co "krasnoyarskiy Zavod Tsvetnykh Metallov Imeni VN Gulidova" "krastsvetmet" Jsc
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/42—Platinum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/44—Palladium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/46—Ruthenium, rhodium, osmium or iridium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00—Nitrogen; Compounds thereof
    • C01B21/20—Nitrogen oxides; Oxyacids of nitrogen; Salts thereof
    • C01B21/24—Nitric oxide (NO)
    • C01B21/26—Preparation by catalytic or non-catalytic oxidation of ammonia

Definitions

  • the claimed group of inventions relates to the field of catalytic elements, in particular to variants of catalytic systems that are used for the conversion of ammonia from a gas phase containing oxygen in units for producing nitric and hydrocyanic acids, as well as hydroxylamine sulfate.
  • the catalytic system consists of a package of platinum-based catalyst gauzes and a package of palladium-based collecting gauzes.
  • the catalyst gauzes participate in the catalytic oxidation of ammonia
  • the collecting gauzes are located downstream of the gas flow under the catalyst gauzes and collect sublimating platinum and rhodium from the catalyst gauzes, and also additionally oxidize the ammonia that has not reacted on the catalyst gauzes.
  • inevitable chemical losses of precious metals occur, which cause destruction of the catalyst and collecting gauzes, which leads to mechanical losses of precious metals in the form of particles and wire fragments and, as a consequence, to a decrease in the service life.
  • This arrangement of soft gaskets allows to significantly reduce the negative effects of turbulent pulsations of the gas flow passing through the grids, and thus prevent the rupture of the catching grids in the catcher package into separate pieces, which leads to the exclusion of ammonia breakthrough and, as a consequence, ensures the concentration of ammonia in the gas mixture behind the catcher package at an explosion-proof level of less than 0.03 vol.%.
  • the disadvantage of the said catalytic element revealed by the results of the analysis of the operational characteristics of the catalytic systems and the analysis of the surface of the spent catalyst gauzes on a scanning electron microscope, is the overlap of a significant part of the active surface of the catalyst gauzes up to 50-60% with silica inert fibers of the gasket material, which leads to a decrease in the degree of ammonia conversion and increased losses of precious metals from the remaining open surface of the catalyst gauzes, which experiences high tension and ammonia load per unit area. Subsequently, this disadvantage played a major role in the refusal to use anti-pulsation gaskets based on silica material between the catalyst gauzes.
  • the task was set to increase the strength of catalyst gauzes by reducing the mechanical losses of platinum group metals from precious metal gauzes while maintaining the high catalytic activity of these gauzes.
  • each invention is a reduction in the loss of platinum group metals from the catalytic system in ammonia oxidation units, which makes it possible to reduce the loss of platinum group metals and increase the service life while maintaining a high degree of conversion without increasing the investment of precious metals.
  • the activated meshes are made of woven wire with a diameter of 0.07-3.00 mm, the material of the activated meshes is heat-resistant high-alloy or precision steel, or nichrome alloys;
  • the first alloy is made on the basis of a double platinum-rhodium system with a rhodium content from 0.1 wt. % to 50 wt. %, wherein the second alloy is made on the basis of a triple platinum-palladium-rhodium system with a palladium content from 0.1 wt. % to 95 wt. % and rhodium from 1 wt. % to 50 wt. %.
  • the double platinum-rhodium system is understood to be an alloy containing two main components (platinum and rhodium) and inevitable impurities (for example, palladium, iridium, etc., no more than 1 wt.%).
  • the triple platinum-palladium-rhodium system is an alloy containing three main components (platinum, palladium and rhodium) and inevitable impurities (for example, iridium, etc., no more than 1 wt.%).
  • a net pack is a set of 2 or more nets.
  • the first alloy is made on the basis of a double platinum-rhodium system with a rhodium content of 3 May % to 12 May %, preferably 4 May % to 10 May %, while the second alloy is made based on the triple platinum-palladium-rhodium system with a palladium content of from 3 May % to 70%, preferably from 3 May % to 60 May %, and rhodium of from 1 May % to 10 May %, preferably from 2 May % to 6 May %.
  • the activated grids are made of intertwined wires with a diameter of 0.07-1.0 mm, preferably 0.15-0.41 mm, with the formation of cells in such a way that when the activated grid is illuminated, light penetrates through no more than 15% of the total area of the grid, preferably no more than 10% of the total area of the grid.
  • the area of the grid is understood to be its area obtained by multiplying the length by the width.
  • the system additionally contains the following installed along the gas flow:
  • the system further comprises a palladium-based catching grid package installed along the gas flow path and an activated grid or a package of activated grids.
  • the activated meshes are made woven from wire with a diameter of 0.07-3.00 mm, the material of the activated meshes is heat-resistant high-alloy or precision steel, or nichrome alloys;
  • the first alloy is made on the basis of a double platinum-rhodium system with a rhodium content from 0.1% to 50%, while the second alloy is made on the basis of a triple platinum-palladium-rhodium system with a palladium content from 0.1 wt. % to 95 wt. % and rhodium from 1 wt. % to 50 wt. %.
  • the first alloy is made on the basis of a binary platinum-rhodium system with a rhodium content of 3 May % to 12 May %, preferably from 4 May % to 10 May %
  • the second alloy is made on the basis of a ternary platinum-palladium-rhodium system with a palladium content of 3 May % to 70 May %, preferably from 3 May % to 60 May %, and rhodium of 1 May % to 10 May %, preferably from 2 May % to 6 May %.
  • the activated grids are made of intertwined wires with a diameter of 0.07-1.0 mm, preferably 0.15-0.41 mm, with the formation of cells in such a way that when the activated grid is illuminated, light penetrates through no more than 15% of the total area of the grid, preferably no more than 10% of the total area of the grid.
  • the area of the grid is understood to be its area obtained by multiplying the length by the width.
  • the activated meshes are made of woven wire with a diameter of 0.07-3.00 mm, the material of the activated meshes is heat-resistant high-alloy or precision steel, or nichrome alloys;
  • the first alloy is made on the basis of a double platinum-rhodium system with a rhodium content from 0.1 wt. % to 50 wt. %, wherein the second alloy is made on the basis of a triple platinum-palladium-rhodium system with a palladium content from 0.1 wt. % to 95 wt. % and rhodium from 1 wt. % to 50 wt. %.
  • the first alloy is made on the basis of a binary platinum-rhodium system with a rhodium content of 3 May % to 12 May %, preferably from 4 May % to 10 May %
  • the second alloy is made on the basis of a ternary platinum-palladium-rhodium system with a palladium content of 3 May % to 70 May %, preferably from 3 May % to 60%, and rhodium of 1 May % to 10 May %, preferably from 2 May % to 6 May %.
  • the activated grids are made of intertwined wires with a diameter of 0.07-1.0 mm, preferably 0.15-0.41 mm, with the formation of cells in such a way that when the activated grid is illuminated, light penetrates through no more than 15% of the total area of the grid, preferably no more than 10% of the total area of the grid.
  • the area of the grid is understood to be its area obtained by multiplying the length by the width.
  • a method for manufacturing the above-mentioned catalytic system for the oxidation of ammonia characterized in that, to obtain an activated mesh, the surface of the mesh is fired with a hydrogen or nitrogen-hydrogen, or propane flame, or the meshes are heat-treated at a temperature of 150-600°C, then the surface of the activated mesh is etched in a solution of sulfuric or hydrochloric acid, or nitric acid, or a mixture of hydrochloric and nitric acids, at a temperature of 20-90°C for 0.25-20 min with stirring, or treated by electrochemical etching with stirring.
  • the surface of the activated mesh is etched in a solution with a hydrochloric acid concentration of 1-36% at a temperature of 20-90°C for 0.25-20 min with stirring.
  • the surface of the activated mesh is etched in a solution of a mixture of hydrochloric and nitric acid with a total concentration of 1-50% at a temperature of 20-90°C for 0.10-20 min with stirring.
  • the surface of the activated mesh is treated by electrochemical etching at a temperature of 20-80°C for 0.25-20 min with stirring.
  • the surface of the activated meshes is mechanically processed using sandpaper or a brush with metal bristles, or by sandblasting.
  • platinum group metals are applied to the surface of the activated mesh through an intermediate layer based on aluminum oxide.
  • the surface of the mesh is fired with a hydrogen or nitric-hydrogen flame at a temperature of 500-700°C, or with a propane flame at a temperature of 500-1200°C, or the meshes are heat-treated in a furnace at a temperature of 150-600°C.
  • the surface of the activated mesh is etched in a solution with a hydrochloric acid concentration of 1-36% at a temperature of 20-90°C for 0.25-20 min with stirring.
  • the surface of the activated mesh is etched in a solution of a mixture of hydrochloric and nitric acid with a total concentration of 1-50% at a temperature of 20-90°C for 0.10-20 min with stirring.
  • the surface of the activated mesh is treated by electrochemical etching at a temperature of 20-80°C for 0.25-20 min with stirring.
  • the catalytic system comprises a first catalytic grid made of a first platinum-based alloy, a first activated grid, a first catalytic grid made of a second platinum-based alloy, a second activated grid, a stack of palladium-based catching grids, and a third activated grid, installed along the gas flow path;
  • - activated grids are made of woven wire with a diameter of 0.07-3.00 mm, with cells that are not visible through the light, while the material of the activated grids is heat-resistant high-alloy or precision steel, or nichrome alloys;
  • the first alloy is made on the basis of a double platinum-rhodium system with a rhodium content from 0.1 wt. % to 50 wt. %
  • the second alloy is made on the basis of a triple platinum-palladium-rhodium system with a palladium content from 0.1 wt. % to 95 wt. % and rhodium from 1 wt. % to 50 wt. %.
  • a package of first catalyst grids of the first platinum-based alloy is installed instead of the first catalyst grid of the first platinum-based alloy. Instead of the first activated grid, a first package of activated grids is installed. Instead of the first catalyst grid of the second platinum-based alloy, a package of catalyst grids of the second platinum-based alloy is installed. Instead of the second activated grid, second package of activated grids. The third package of activated grids is installed instead of the third activated grid.
  • the catalytic system comprises a first catalytic grid made of a first platinum-based alloy or a second platinum-based alloy, a first activated grid, a stack of palladium-based catching grids, and a second activated grid, installed along the gas flow path;
  • - activated grids are made of woven wire with a diameter of 0.07-3.00 mm, with cells that are not visible through the light, while the material of the activated grids is heat-resistant high-alloy or precision steel, or nichrome alloys;
  • the first alloy is made on the basis of a double platinum-rhodium system with a rhodium content from 0.1 wt. % to 50 wt. %
  • the second alloy is made on the basis of a triple platinum-palladium-rhodium system with a palladium content from 0.1 wt. % to 95 wt. % and rhodium from 1 wt. % to 50 wt. %.
  • a package of catalytic grids of the first platinum-based alloy is installed, or instead of the first catalytic grid of the second platinum-based alloy, a package of catalytic grids of the second platinum-based alloy is installed.
  • the first activated grid the first package of activated grids is installed, instead of the second activated grid, the second package of activated grids is installed.
  • the catalytic system comprises a first catalytic grid made of a first platinum-based alloy, a first activated grid, a first catalytic grid made of a second platinum-based alloy, and a second activated grid, installed along the gas flow path;
  • - activated grids are made of woven wire with a diameter of 0.07-3.00 mm, with cells that are not visible through the light, while the material of the activated grids is heat-resistant high-alloy or precision steel, or nichrome alloys;
  • the first alloy is made on the basis of a double platinum-rhodium system with a rhodium content from 0.1 wt. % to 50 wt. %
  • the second alloy is made on the basis of a triple platinum-palladium-rhodium system with a palladium content from 0.1 wt. % to 95 wt. % and rhodium from 1 wt. % to 50 wt. %.
  • a package of catalytic grids of the first platinum-based alloy is installed, instead of the first activated grid, a first package of activated grids is installed.
  • a package of catalytic grids of the second platinum-based alloy is installed.
  • a second package of activated grids is installed.
  • the catalytic system comprises a first catalytic grid made of a first platinum-based alloy or a second platinum-based alloy, and an activated grid, installed in the direction of gas flow;
  • the activated mesh is made of woven wire with a diameter of 0.07-3.00 mm, with cells that are not visible through the light, while the material of the activated mesh is heat-resistant high-alloy or precision steel, or nichrome alloys;
  • the first alloy is made on the basis of a double platinum-rhodium system with a rhodium content from 0.1 wt. % to 50 wt. %
  • the second alloy is made on the basis of a triple platinum-palladium-rhodium system with a palladium content from 0.1 wt. % to 95 wt. % and rhodium from 1 wt. % to 50 wt. %.
  • a package of catalytic grids of the first platinum-based alloy is installed, or instead of the first catalytic grid of the second platinum-based alloy, a package of catalytic grids of the second platinum-based alloy is installed.
  • a first package of activated grids is installed.
  • the catalytic system comprises, installed along the gas flow path, a first catalytic grid made of a first platinum-based alloy, a first catalytic grid made of a second platinum-based alloy, a first activated grid, a stack of palladium-based catching grids, and a second activated grid;
  • - activated grids are made of woven wire with a diameter of 0.07-3.00 mm, with cells that are not visible through the light, while the material of the activated grids is heat-resistant high-alloy or precision steel, or nichrome alloys;
  • the first alloy is made on the basis of a double platinum-rhodium system with a rhodium content from 0.1 wt. % to 50 wt. %
  • the second alloy is made on the basis of a triple platinum-palladium-rhodium system with a palladium content from 0.1 wt. % to 95 wt. % and rhodium from 1 wt. % to 50 wt. %.
  • a package of catalytic grids of the first platinum-based alloy is installed instead of the first catalytic grid of the first platinum-based alloy.
  • a package of catalytic grids of the second platinum-based alloy is installed instead of the first activated grid, the first package of activated grids is installed, instead of the second activated grid, the second package of activated grids is installed.
  • the catalytic system comprises, installed along the gas flow path, a first catalytic grid made of a first platinum-based alloy, a first catalytic grid made of a second platinum-based alloy, a stack of palladium-based catching grids, and an activated grid;
  • - activated grids are made of woven wire with a diameter of 0.07-3.00 mm, with cells that are not visible through the light, while the material of the activated grids is heat-resistant high-alloy or precision steel, or nichrome alloys;
  • the first alloy is made on the basis of a double platinum-rhodium system with a rhodium content from 0.1 wt. % to 50 wt. %
  • the second alloy is made on the basis of a triple platinum-palladium-rhodium system with a palladium content from 0.1 wt. % to 95 wt. % and rhodium from 1 wt. % to 50 wt. %.
  • a stack of catalytic grids of the first platinum-based alloy is installed instead of the first catalytic grid of the first platinum-based alloy. Instead of the first catalytic grid of the second platinum-based alloy, a stack of catalytic grids of the second platinum-based alloy is installed. Instead of the first activated grid, a first stack of activated grids is installed.
  • the essence of the claimed method is that in the method for manufacturing all the above-mentioned variants of the device for reducing mechanical losses of platinum group metals from a catalytic system for oxidation of ammonia, activated meshes are fired with a hydrogen or nitrogen-hydrogen, or propane flame, or thermal treatment of the activated meshes is carried out at a temperature of 150-600°C. Then the surface of the wire of the activated mesh is etched in a solution of diluted sulfuric or hydrochloric acids, or nitric acid, or a mixture of hydrochloric and nitric acids, at a temperature of 20-90°C for 0.25-20 min with stirring, or treated by electrochemical etching with stirring.
  • the surface of the activated mesh wire can be etched in a solution with a hydrochloric acid concentration of 1-36% at a temperature of 20-90°C for 0.25-20 min with stirring.
  • the surface of the activated mesh wire can be etched in a solution of a mixture of hydrochloric and nitric acid with a total concentration of 1-50% at a temperature of 20-90°C for 0.10-20 min with stirring.
  • the surface of the activated mesh wire is preferably treated by electrochemical etching at a temperature of 20-80°C for 0.25-20 min with stirring.
  • the surface of the activated meshes can be mechanically processed using sandpaper or a brush with metal bristles, or sandblasted.
  • Platinum group metals can be applied to the surface of the activated mesh through an intermediate layer.
  • Figure 1 shows a diagram of the arrangement of activated grids in the device according to variant 1;
  • Fig. 2 shows a diagram of the arrangement of activated grids in the device according to variant 2;
  • Fig. 3 shows a diagram of the arrangement of activated grids in the device according to variant 3;
  • Fig. 4 shows a diagram of the arrangement of activated grids in the device according to variant 4;
  • Fig. 5 shows a diagram of the arrangement of activated grids in the device according to variant 5;
  • Fig. 6 - diagram of the arrangement of activated grids in the device according to variant 6;
  • Fig. 9 - activated grid (top view);
  • Fig. 10 cell of the activated grid;
  • Fig. 11 section A-A of Fig. 3, Fig. 12 - section B-B of Fig. 3.
  • KS catalyst grid
  • US palladium-based catching grid package with separating grids
  • SAT - activated grid
  • the package may contain two or more meshes, the first alloy being an alloy based on a double platinum-rhodium system with a rhodium content from 0.1 wt. % to 50 wt. %, the second alloy being an alloy based on a triple platinum-palladium-rhodium system with a palladium content from 0.1 wt. % to 95 wt. % and rhodium from 1 wt. % to 50 wt. %.
  • a package of catalyst nets made of a first platinum-based alloy, a first package of activated nets, a package of catalyst nets made of a second platinum-based alloy, a second package of activated nets, a package of palladium-based catching nets and a third package of activated nets are installed along the gas flow (Fig. 1).
  • a package of catalyst grids made of a first platinum-based alloy or a second platinum-based alloy, a first package of activated grids, a package of palladium-based catching grids, and a second package of activated grids are installed along the gas flow path (Fig. 2).
  • a package of catalyst meshes made of a first platinum-based alloy, a first package of activated meshes, a package of catalyst meshes made of a second platinum-based alloy, and a second package of activated meshes are installed along the gas flow path (Fig. 3).
  • a package of catalyst grids made of a first platinum-based alloy or a second platinum-based alloy and a package of activated grids are installed along the gas flow path (Fig. 4).
  • a package of catalyst grids made of a first platinum-based alloy, a package of catalyst grids made of a second platinum-based alloy, a first package of activated grids, a package of catching grids based on palladium, and a second package of activated grids are installed along the gas flow (Fig. 5).
  • a package of catalyst grids made of a first platinum-based alloy, a package of catalyst grids made of a second platinum-based alloy, a package of catching grids based on palladium, and a package of activated grids are installed along the gas flow (Fig. 6).
  • the activated grids (Fig. 7, 8, 9) are made woven from wire with a diameter of 0.07-3.00 mm, with the formation of cells in such a way that when the activated grid is illuminated, light penetrates no more than 15% of the total area of the grid, preferably no more than 10% of the total area of the grid.
  • the area of the grid is understood to be its area obtained by multiplying the length by the width.
  • the material of the activated grids is:
  • Activated grids stabilize the gas flow over the entire surface area of the grid due to the preferential redistribution of the normal component of the gas flow, directed vertically to the surface of the grids, to the tangential component - along the surface of the grids (see Figs. 10, 11, 12).
  • the mesh To activate the surface of the mesh, it is fired with a hydrogen or nitric-hydrogen or propane flame, or the mesh is heat treated at a temperature of 500-700°C.
  • the surface of the activated mesh wire is etched in a solution of diluted sulfuric or hydrochloric acids, or nitric acid, or a mixture of hydrochloric and nitric acids, at a temperature of 20-90°C for 0.25-20 min with stirring, or treated by electrochemical etching with stirring.
  • the surface of the mesh wire is etched in a solution containing 1-50% sulfuric acid.
  • the surface of the activated mesh wire can be etched in a solution with a hydrochloric acid concentration of 1-36% at a temperature of 20-90°C for 0.25-20 minutes with stirring.
  • the surface of the activated mesh wire can be etched in a solution of a mixture of hydrochloric and nitric acid with a total concentration of 1-50% at a temperature of 20-90°C for 0.10-20 min with stirring.
  • the surface of the activated mesh wire can be treated by electrochemical etching at a temperature of 20-80°C for 0.25-20 min with stirring.
  • the surface of the activated meshes is mechanically processed with sandpaper or a brush with metal bristles, or by sandblasting.
  • sandpaper or a brush with metal bristles or by sandblasting.
  • lubricants from equipment parts containing carbon, which blocks the surface of the wire are almost completely removed from the surface of the wire, the surface of the mesh becomes rough, which leads to an increase in the strength of the mechanical adhesion of platinoid particles evaporating from the platinoid meshes.
  • the degree of capture increases by 5-10% for activated meshes compared to similar meshes made of smooth wire.
  • platinoids are applied to the surface of the activated grid through the intermediate layer using any of the known methods (in particular, Russian patent RU 2169614, [4]). Platinoids on the activated grids further oxidize the unreacted ammonia from the catalyst grids and thus evenly distribute the ammonia oxidation reaction over the depth of the catalytic system package.
  • Activated grids are made of intertwined wires with a diameter of 0.07-1.0 mm, forming cells in such a way that when the activated grid is illuminated, light penetrates no more than 15% of the total grid area, preferably no more than 10% of the total grid area.
  • the grid area is understood to be its area obtained by multiplying the length by the width.
  • the catching effect is achieved due to the high contact area of the surface of the activated meshes with the platinum group particles in the gas flow, evaporating from the catalyst meshes, which is more than 5 times greater than the surface of woven meshes with cells per transmission made of the same diameter of the warp and weft wire (see Fig. 8).
  • the degree of catching of platinum group metals by the activated meshes is up to 30%.
  • the catching effect is also achieved, as described above, due to the high contact area of the activated mesh surface with the platinum group particles when the gas flow flows around the surface of the wire of the catching mesh.
  • the degree of catching of platinum group metals by activated meshes is up to 30%.
  • Example 1 Catalytic system according to variant 4a.
  • a grid of Kh23Yu5 steel with a diameter of 2900 mm, made of warp wire with a diameter of 0.22 mm and weft wire with a diameter of 0.16 mm, activated by a hydrogen flame at a temperature of 700°C was placed under a catalyst grid of PlRd 95-5 alloy (95 wt. % platinum and 5 wt. % rhodium) with a diameter of 2900 mm in the direction of gas flow.
  • PlRd 95-5 alloy 95 wt. % platinum and 5 wt. % rhodium
  • the catalyst grid retained its integrity without the formation of tears and cracks, the degree of capture of platinum group metals after refining processing of the activated grid was more than 10%.
  • the excess mileage of the catalyst grid relative to the standard The value of 7920 hours was more than 1000 hours while maintaining the degree of ammonia conversion at the level of 95.5-97% throughout the entire run.
  • Example 2 Catalytic system according to variant 6b.
  • Example 3 Catalytic system according to variant 4b.
  • Example 5 Catalytic system according to variant 4b.
  • Example 6 Similar to example 3, but additionally platinum was applied to the surface of the activated grids by any of the known methods, in particular by the method described in Russian patent RU 2169614 (passed into the public domain), in which platinum was applied to the carrier through an intermediate layer on The platinum group metals are applied on the basis of modified aluminum oxide. After operation for 2300 hours, the catalyst grids retained their integrity, the degree of platinum group metals capture after refining processing of activated grids was more than 6%. The overrun of the catalyst grids relative to the standard value of 2160 hours was more than 100 hours, while maintaining the calculated degree of ammonia conversion at a high level of 91.0-92% throughout the entire run.
  • ABS Abbreviations: "ABC” - ammonia-air mixture; "KA” - contact apparatus; “abs. atm” - absolute pressure in atmospheres; "KS” - catalyst grid; “US” - a pack of collecting grids with separating grids; “SAT” - activated grid; "MPG” - platinum group metals; "AK” - nitric acid; “SK” hydrocyanic acid; "GAS” - hydroxylamine sulfate; "NNS” - nitrite-nitrate salts.
  • PlRd 95-5 contains 95% platinum and 5% rhodium
  • PlRd 92.5-7.5 contains 92.5% platinum and 7.5% rhodium
  • PlRd 92-8 contains 92% platinum and 8% rhodium
  • PlPdRd 81-16-3 contains 81% platinum, 16% palladium and 3% rhodium;
  • PlPdRd 60-37-3 contains 60% platinum, 37% palladium and 3% rhodium
  • PDN-5 contains 95% palladium and 5% nickel.
  • Variants of the method for producing a catalytic system for the oxidation of ammonia were also investigated.
  • the resulting devices were used in ammonia oxidation units, where they made it possible to reduce the loss of platinum group metals from the catalytic system and equalize the gas flow.
  • the claimed invention ensured a reduction in the loss of platinum group metals from the catalytic system in ammonia oxidation units, an increase in the service life while maintaining a high degree of conversion without increasing the investment of precious metals, and also the equalization of the gas flow.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Catalysts (AREA)

Abstract

Un système catalytique d'oxydation d'ammoniac comprend, disposés dans le sens de déplacement du gaz : un maillage de catalyseur ou un paquet de maillages de catalyseur faits d'un premier alliage à base de platine ou d'un second alliage à base de platine; un maillage activé ou un paquet de maillages activés; les maillages activés sont tissés à partir de fibres d'un diamètre de 0,07-3,0 mm, le matériau des maillages activés consiste en de l'acier thermorésistant fortement dopé ou de précision, ou en des alliages de nickel-chrome. Le résultat technique de chacune de ces inventions consiste en une diminution des pertes en platinoïdes et d'augmenter la durée d'exploitation tout en conservant un niveau élevé de conversion sans augmenter les dépenses en métaux précieux.
PCT/RU2024/050104 2023-05-19 2024-05-18 Système catalytique d'oxydation de l'ammoniac (variantes) et procédé de production Ceased WO2024242593A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB785657A (en) * 1954-09-17 1957-10-30 Du Pont Catalyst for gas phase oxidation reactions and processes effected therewith
RU2119381C1 (ru) * 1997-06-27 1998-09-27 Открытое акционерное общество "Екатеринбургский завод по обработке цветных металлов" Устройство для улавливания платиноидов при каталитическом окислении аммиака
RU2155097C1 (ru) * 2000-01-14 2000-08-27 Хальзов Павел Иванович Каталитический элемент для конверсии аммиака
RU2499766C1 (ru) * 2012-05-31 2013-11-27 Общество с ограниченной ответственностью "ТЕРМОКЕМ" Способ каталитического окисления аммиака
EP3680015A1 (fr) * 2019-01-14 2020-07-15 Heraeus Deutschland GmbH & Co KG Système de catalyseur ainsi que procédé de combustion catalytique d'ammoniac en oxyde d'azote dans une installation moyenne pression
RU2776371C1 (ru) * 2019-05-22 2022-07-19 Джонсон Мэттей Паблик Лимитед Компани Катализаторная сетка

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB785657A (en) * 1954-09-17 1957-10-30 Du Pont Catalyst for gas phase oxidation reactions and processes effected therewith
RU2119381C1 (ru) * 1997-06-27 1998-09-27 Открытое акционерное общество "Екатеринбургский завод по обработке цветных металлов" Устройство для улавливания платиноидов при каталитическом окислении аммиака
RU2155097C1 (ru) * 2000-01-14 2000-08-27 Хальзов Павел Иванович Каталитический элемент для конверсии аммиака
RU2499766C1 (ru) * 2012-05-31 2013-11-27 Общество с ограниченной ответственностью "ТЕРМОКЕМ" Способ каталитического окисления аммиака
EP3680015A1 (fr) * 2019-01-14 2020-07-15 Heraeus Deutschland GmbH & Co KG Système de catalyseur ainsi que procédé de combustion catalytique d'ammoniac en oxyde d'azote dans une installation moyenne pression
RU2776371C1 (ru) * 2019-05-22 2022-07-19 Джонсон Мэттей Паблик Лимитед Компани Катализаторная сетка

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