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Method for catalytic oxidation of ammonia Method for catalytic oxidation of ammonia involves passing an ammonia/air mixture through a two-step catalyst stack of an industrial assembly, having a catalyst stack of platinoid meshes of first oxidation state, a catalyst of second oxidation state which is a stack of meshes of stainless steel with thread diameter of 0.10-0.30 mm whose surface if coated with platinum and placed against the catalyst stack of first oxidation state, as well as a platinum collector, having a stack of 3-5 platinum wire gauzes containing a component selected from: PdW (95/5); Pd/Ni (95/5). |
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Device and method for catalytic gas phase reactions and their application Invention relates to catalytic exothermic gas-phase reactions and reactor to this end. Proposed reactor comprises inlet zone 1, reaction zone 2 including at least one catalyst 4, and product gas outlet zone 3, along arranged along raw gas flow. In said inlet zone 1 or inlet zone 1 and reaction zone 2, reactor has coolant transfer device composed of isolating shell 6 to decrease heat transfer from reaction zone 2 to inlet zone, hence, to decrease risks of premature ignition of raw gas mix or to rule out undesirable side reactions in inlet zone 1. Reactor inner walls in inlet zone 1 or inlet zone and reaction zone 2 consist of inert material. |
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Catalyst, preparation method thereof and ammonia oxidation method Invention relates to catalysts and ammonia oxidation processes. Described is a catalyst for oxidation of ammonia to NO and NO2 and decomposition of NO2 for use as the second step of a two-step catalyst system which is formed using various methods, as well as in a set with platinioid meshes, trapping meshes and/or inert filling, under Ostwald process conditions at 800-920°C and pressure 1-9 bars, as well as under ammonia slip conditions, which is a block carrier with a cellular structure containing an aluminium, cerium, zirconium or titanium oxide with a deposited active component, where the carrier has open transport pores with size 300-2000 Å, where the volume of such pores is not less than 0.25 cm3/g, the active component has the formula LayM1 1-xM2 xOz, where: M1 is selected from a group consisting of Fe, Mn, Co; M2 - Co, Cu, Ni, Zn, Mg; x=0-0.4, y=0-0.99, z=2; M1 is selected from a group consisting of Fe, Mn, Co; M2 - Co, Cu, Ni, Zn, Mg; x=0-0.4, y=0-0.99, z=2-4. Described is a method of preparing the catalyst by mixing powder of an aluminium, cerium, zirconium or titanium oxide with particle characteristic size of 5-100 mcm with any of the commonly used inorganic binding materials based on aluminium oxide, water, acid, plasticising and high-temperature combustible additives, and the active component is deposited on the carrier via saturation with aqueous solutions containing polymerised ester precursors of the active component. The invention also describes the process of oxidising ammonia under Ostwald process conditions at 800-920°C and pressure 1-9 bars, as well as under ammonia slip conditions using the catalyst described above. |
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Method for thermal treatment of iron oxide-based block catalyst with cellular structure Described is a method for thermal treatment of an iron oxide-based block catalyst with a cellular structure, characterised by that thermal treatment of the blocks is carried out in steps, and specifically as follows: blocks are first dried at temperature 20-25°C for not less than 120 h and the air-dried blocks then undergo preliminary step-by-step calcination: while raising temperature to 100-110°C at a rate of 5-7°C/h, holding the blocks at temperature 100-110°C for not less than 10 h; while raising temperature to 250-270°C at a rate of 30-35°C/h, holding the blocks at temperature 250-270°C for not less than 6 h; while raising temperature to 400-410°C at a rate of 50-55°C/h, holding the blocks at temperature 400-410°C for not less than 6 h; and then raising temperature to 950-970°C at a rate of 50-60°C/h and holding the blocks at temperature 950-970°C for not less than 10 h. |
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Packet of catalyst grids for converting ammonia Invention relates to a packet of catalyst grids for converting ammonia in a gas mixture containing oxygen, made from platinoid alloys, and can be used in nitric and hydrocyanic acid, as well as hydroxylaminosulphate plants. The packet of catalyst grids for converting ammonia in a gas mixture containing oxygen, includes a grid layer made from platinoid alloys with low 70 to 85% and high 90 to 95% concentration of platinum, distinguished by that, the packet consists of three layers, where the first layer along the path of the gas mixture has grids made from an alloy with low concentration of platinum, the number of which is 1/6 to1/3 of the total number of grids in the packet, the second layer has grids made from an alloy with high concentration of platinum, numbering from 1/3 to 2/3 of the total number of grids in the packet, and the third layer has grids made from an alloy with low and/or with high concentration of platinum. |
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Catalyst and method of converting ammonia Description is given of a catalyst for converting ammonia to nitrogen (II) oxide with a block cellular structure, with the shape of a rectangular prism or oblique prism with obliquity of 0-45°, coefficient of thermal expansion in the interval 10-7-10-5 K-1 in the temperature range of 900°C, based on mixed oxides with general formula: xMe1O·yMe2O·(1-x-y)(2MgO·(2-z)Al2O3·(5+z)SiO2), where: x=0.03-0.25; y=0.01-0.1; z=0-2, Me1 - is an active component; Me2 - is a structural promoter. Described also is a method of catalytic conversion of ammonia, which involves passing a reaction gaseous mixture, containing ammonia and an oxygen containing gas, through a two-stage catalyst system, made using different methods, including in a set with trapping platinoid gauze and/or inert packing. The proposed catalyst is used in the second stage. |
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Development of improved catalyst download Initial gas-flow passes the first ammonia oxidation stage containing the catalyst (the metal of platinum group with large surface area) whereat it is converted with the yield 20 - 99% to the nitrogen oxides. Then the gas mix containing the nitrogen oxides, oxygen and unreacted ammonia pass the second ammonia oxidation stage containing the catalyst promoting as well the destruction of N2O. The second stage products contain the traces of unreacted ammonia and less than 500 ppm of N2O. The process is carried out at temperature range 700 - 1000°C. The method of catalyst download for the implementation of aforementioned process is claimed. The preferable implementation versions allow obtaining of the low N2O yields and increasing of the catalyst operating life. |
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Catalyst for ammonium oxidation Invention relates to production of nitric acid and concerns catalyst for ammonium oxidation. Described is catalyst for ammonium oxidation, which represents alloy containing platinum, palladium, rhodium, ruthenium and admixtures, which has the following composition (wt %): palladium 40-90, the rest being rhodium and/or ruthenium to 1.0, iridium to 2.0, admixtures to 0.15, platinum. |
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Method of obtaining oxide catalysts on a substrate Invention pertains to the method of obtaining porous substances on a substrate for catalytic applications, to the method of obtaining porous catalysts for decomposition of N2O and their use in decomposing N2O, oxidising ammonia and reforming methane with water vapour. Description is given of the method of obtaining porous substances on a substrate for catalytic applications, in which one or more soluble precursor(s) metal of the active phase is added to a suspension, consisting of an insoluble phase of a substrate in water or an organic solvent. The suspension undergoes wet grinding so as to reduce the size of the particles of the substrate phase to less than 50 mcm. The additive is added, which promotes treatment before or after grinding. A pore-forming substance is added and the suspension, viscosity of which is maintained at 100-5000 cP, undergoes spray drying, is pressed and undergoes thermal treatment so as to remove the pore-forming substance, and is then baked. Description is also given of the method of obtaining porous catalysts on a substrate for decomposing N2O, in which a soluble cobalt precursor is added to a suspension of cerium oxide and an additive, promoting treatment, in water. The suspension is ground to particle size of less than 10 mcm. A pore-forming substance, viscosity of which is regulated to approximately 1000 cP, is added before the suspension undergoes spray drying with subsequent pressing. The pore-forming substance is removed and the product is baked. Description is given of the use of the substances obtained above as catalysts for decomposition of N2O, oxidation of ammonia and reforming of methane with water vapour. |
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Catalytic element for heterogeneous high-temperature reactions 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. |
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N2o decomposition catalyst in ostwald process Decomposition if N2O under Ostwald process conditions at 750-1000°C and pressure 0.9-15 bar is conducted on catalyst, which comprises (A) support composed of α-Al2O3, ZrO2, SeO2, or mixture thereof and (B) supported coating composed of rhodium or rhodium oxide, or mixed Pd-Rh catalyst. Apparatus wherein N2O is decomposed under Ostwald process conditions on the above-defined catalyst is also described. Catalyst is disposed successively downstream of catalyst grids in direction of stream of NH3 to be oxidized. |
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Platinoid mesh catalytic agent The invention is pertaining to the field of the chemical industry, in particular, to production of the nitric acid, nitric fertilizers, the cyanhydric acid, the nitrites and nitrates and to other productions of chemical products, where the flow sheet of production provides for the catalytic conversion of ammonia up to the nitrogen oxides with usage of the platinoid mesh catalytic agents. The platinoid mesh catalytic agent formed in the form of the catalytic package produced out of the layer-by-layer stacked wire catalytic meshes and weaved out of the wires with the diameter of 0.06-0.1 mm consisting of the alloys of platinum with rhodium, palladium, ruthenium and other metals of the platinum group differs that the catalytic package consists of two different in the geometry of the braiding types of the meshes sequentially alternating in the height of the package. At that the geometry of the braiding of the first type of the catalytic meshes is characterized by the number of the wires interlacing per 1 cm2 in the interval of 1024-450, and the geometry of the braiding of the second type of the catalytic meshes is characterized by the number of the wires interlacing per 1 cm2 in the interval of 400-200. The technical result of the invention is the increased conversion of ammonia and the decreased share of the platinoids included in the mesh catalytic agent production processes providing for the catalytic conversion of ammonia in the flow sheet of the chemical goods production. |
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Method of intensification of the installation for production of nitric acid The invention is pertaining to the method of intensification of the installations for production of the non-concentrated nitric acid and may be used for raising productivity of the installations for production of the non-concentrated nitric acid under pressure. The invention provides for creation of the excess pressure on the inlet of the air compressor by preliminary compression of the atmospheric air in the high-pressure fan. At that the heat of the compression process in the warm season of the year is withdrawn by the direct contact with the water at the inlet of the fan, and in the cold season the heat is used for heating, at that in full or partially excluding heating of the air in the preheater mounted to prevent the icing up of the guiding apparatuses of the air compressor. At the enterprises with the high degree of the air dusting or chemical pollution for the contact cooling of the air by water it is possible to use scrubbers-washers, which combine the functions of the air cooler and the purification device. The method is effective for the operating installations, in which as a result of the wear-out of the flow-through section of the air compressors and the gas turbines decreases not only productivity, but also the pressure in the system, and as the result of it the concentration of the nitric acid. The method allows to realize the intensification of the installations using already existed equipment due to the increased pressure in the system. Concentration of the nitric acid is not lowered, the degree of purification of the tailing gases is preserved, production cost and the specific consumption of the steam and the natural gas are reduced. |
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The invention is pertaining to the support system for catalytic meshes in the burners for oxygenation of ammonia and to the method of reduction of movement of the particulates of the ceramic substance caused by the thermal expansion. The support system consists of the catalytic meshes (1) and possibly, of the support sieves (2) which are supported by the ceramic filling agents placed in the burner box with metallic walls and the perforated bottom. The support structure (9) is attached to the metallic wall (4) and-or the outer part of the periphery of the bottom (5). The technical result of the invention is development of the support structure, which does not cause damage of the packet from the catalyzer during operation of the burner, and the development of the system preventing movement of the of the particulates of the ceramic substance. |
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Invention relates to ammonia conversion processes based on two-step catalytic system, which can be employed in production of nitric and hydrocyanic acids and in hydroxylamine sulfate production. Process according to invention comprises passing gaseous ammonia- and oxygen-containing mixture through two-step catalytic system, wherein first downstream step is embodied in a wire catalytic grate stack and second step in one or several layers of block honeycomb material, ratio of second-step hydraulic resistance value to the first-step one exceeding 4. Catalytic system steps are spaced from each other by distance equal to at most 10 and preferably 0.5 to 2 effective thickness of block channel σ calculated in terms of formula σ=2(S/(πn)1/2 (1-ε1/2), wherein S represents honeycomb block cross-section area, n number of channels in block, and ε open surface of block. Spacing between the steps is achieved by positioning between them spacing layer of gas-permeable chemically inactive material having hydraulic resistance coefficient below 100, hydraulic resistance of the second step being calculated as summary value of hydraulic resistances of honeycomb and spacing layers. |
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Method of initiating ammonia conversion reaction Proposed method is performed on reticular platinoid catalyst by passing the ammonia-containing gas mixture and oxygen-containing gas through it; local sections of catalyst surfaces are periodically heated to reaction initiating temperature by means of linear electric heating elements located directly on catalyst surface. Equivalent diameters of local sections of catalyst surface are selected between 1-5 of magnitude of external equivalent diameter of separate electric heating element; linear electric heating elements are connected to electric power source at duty factor from 20 to 1 s. Used as material for reticular platinoid catalyst are the following alloys: Pt-81, Pd-15, Rh-3.5 and Ru-0.5 mass-%; Pt-92,5, Pd -4.0 and Rh -3.5 mass-%; Pt-95 and Rh-5 mass-%; Pt-92.5 and Rh-7.5 mass-%. Initiating the ammonia conversion reaction by this method is performed in reactors for production of nitric and hydrocyanic acids and hydroxylamine sulfate. |
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Catalyst and a method of conversion of ammonia The invention is pertinent to the field of chemical industry, in particular to production of a catalysts and processes of oxidation of ammonia in production of a weak nitric acid. The invention offers an ammonia conversion catalyst on the basis of the mixture of oxides of unitized structure and a method oxidation of ammonia in production of weak nitric acid. The catalyst represents a mixture of oxides of the over-all formula (AxByO3Z)k (MmOn)f, (NwPgvOv)r where: A - cation of Ca, Sr, Ba, Mg, Be, Ln or their mixtures; B - cations of Mn, Fe, Ni, Co, Cr, Cu, V, A1 or their mixtures; x=0-2, y=1-2, z=0.8-l.7; M - A1, Si, Zr, Cr, Ln, Mn, Fe, Co, Cu, V, Ca, Sr, Ba, Mg, Be or their mixtures; m=l-3, n=l-2; N - Ti, Al, Si, Zr, Ca, Mg, Ln, W, Mo or their mixtures, P - phosphorus, O - oxygen; w=0-2, g=0-2, v=l-3; k, f and r - mass %, at a ratio (k+f)/r=0-l, f/r=0-l, k/f = 0-100. The catalyst is intended for use in a composition of a two-stage catalytic system generated by different methods, also in a set with the trapping platinoid screens and-or inert nozzles. The technical result ensures 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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Method of nitric acid production and an installation for production of nitric acid The invention is dealt with production of nitric acid with the help of oxidation of ammonia by oxygen of the air and absorption of nitrogen oxides by water in installations with uniform pressure at the stages of oxidation of ammonia and absorption of nitrogen oxides. The method of production of nitric acid in the installations with uniform pressure at the stages of oxidation of ammonia and absorption of nitrogen oxides provides, that compression of the air up to a uniform terminal pressure is conducted continuously within one stage without intermediate cooling and after that the compressed and so heated air is divided into two streams, one of which intended for production of nitric acid is directed to be cooled with further mixing with ammonia, and another is fed directly into a fuel combustion chamber connected with a recuperation turbine. The design embodiment of the installation for production of nitric acid provides for usage in the gas-turbine plant as an air engine for compression of air of an axial-flow compressor mounted directly on a common shaft with the recuperation turbine, at which near the outlet of the air engine the line of a compressed air stream is divided into two parts, one of which intended for production of nitric acid is first connected with a compressed air cooler and then with a mixer of ammonia with air, and the second intended for incineration of fuel is directly connected with the recuperation turbine combustion chamber. Besides in the capacity of a the compressed air cooler they use a "boiling" economizer connected to a line of a feed water for a boiler-utilizer and with a vapor collector of the boiler-utilizer by a line of steam-and-water mixture. The line of the air intended for production of nitric acid is also connected through the reheater of ammonia with a nitric acid blowing column. The technical result is simplification of the method, decreased investments and specific consumption of fuel. |
Another patent 2526681.