Platinoid mesh catalytic agent
FIELD: chemical industry; methods of manufacture of the building structures.
SUBSTANCE: 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.
EFFECT: the invention ensures 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.
The invention relates to the chemical industry, in particular the production of nitric acid, nitrogen fertilizers, hydrocyanic acid, nitrites and nitrates and other chemical products, where technological scheme of production involves the catalytic conversion of ammonia to nitrogen oxides using the platinum wire catalyst, made in the form of a package of layers stacked catalytic wire mesh.
It is widely known use of the platinum wire catalyst for the conversion of ammonia in the form of a package assembled from woven wire layers stacked catalytic nets made of alloys of platinum with rhodium, palladium, ruthenium, and other metals of the platinum group and is woven from filaments (wires) with a diameter of 0.06 to 0.1 mm (for example, Karavaev M.M., Zasorin A.P., Nefclass. Catalytic oxidation of ammonia. - Moscow: Khimiya, 1983, p.41, 55).
This source describes the platinum mesh catalysts for the conversion of ammonia made in the form of a homogeneous package assembled from the same geometry weaving nets, and the package usually contains from 6 to 18 identical grids with the number of tangles 1024 on 1 cm2when the diameter of the wires 0,06-0,1 mm Such platinum wire catalyst packages are predominant in the practical use promyshlennykh processes including technological cycle of catalytic conversion of ammonia to oxides of nitrogen.
The platinum mesh catalysts in the form of a package of layers stacked identical in its geometric structure (the structure of weaving wires) catalytic grids are characterized by significant disadvantages despite their wide use in industry. Based on the analysis of the results of numerous studies of the macro-kinetics and mechanism of oxidation of ammonia on platinum catalytic wires (for example Val, Pihalov, Vindobonian. The study of dynamic features of the processes of reconstruction of the surface of the monolithic platinum-driven heterogeneous catalytic reaction. Surface, 1982, No. 6, s-97 or Val, Pihalov, Viernes. The dynamic features of the oxidation reaction of ammonia on platinum alloys. Chemical industry, 1987, N8, C) found that the platinum wire catalyst, made in the form of a homogeneous package assembled from the same geometry weaving platinum catalytic nets do not provide the maximum possible conversion of ammonia to nitrogen oxides. This is because when such a package structure of that part of its surface that is in direct contact nets among themselves, are not available reagents is virtually excluded from the process of catalysis, i.e. a significant part of the platinum catalyst is expensive ballast. In addition, a uniform package of the platinum catalytic nets can't manage homogeneous, "misyachne" stages of catalytic conversion, i.e. does not allow you to maximize the selectivity of the conversion of ammonia to oxides of nitrogen.
The closest in technical essence and the achieved result is the platinum wire catalyst for the conversion of ammonia in the form of homogeneous catalytic package of layers stacked identical to the platinum catalytic nets in the form of woven wire mesh, woven wire with a diameter of 0.06 to 0.1 mm, manufactured from alloys containing platinum with rhodium, palladium, ruthenium, and other metals of the platinum group (RU patent No. 2212272, CL 01 J 23/42, 01 J 35/04, 01 21/26, 20.09.2003).
Described in this patent, the structure of the platinum mesh, which is woven cell has a rectangular shape with an aspect ratio of 1.1 to 5, and the number of wires in the woven mesh on one centimeter is one of the directions of the woven structure on a duck or on the basis of 10-30 threads, and other area - based or on a duck - 50-34 thread, can improve the efficiency of conversion of ammonia, however, the above-described shortcomings associated with a package structure in which a part of its surface is ness, which is in direct contact nets among themselves, are not available reagents and virtually excluded from the process of catalysis, do not allow full use of the capabilities of the platinum wire catalyst.
Task to be solved by the present invention is directed, is to increase the surface contact of reagents with the platinum wire catalyst.
The technical result achieved when using the platinum wire catalyst is to increase the conversion of ammonia and reducing the attachment of platinum in mesh catalyst in processes including technological scheme of production of chemical products of catalytic conversion of ammonia
The problem is solved and the technical result is achieved due to the fact that the platinum wire catalyst formed in the form of a catalytic package of layers stacked catalytic wire mesh, woven wire with a diameter of 0.06 to 0.1 mm, consisting of alloys of platinum with rhodium, palladium, ruthenium, and other metals of the platinum group, consists of two different geometric weave types of grids sequentially alternating the height of the package, the geometry of the weave of the first type of catalytic grids characterized by the number of twists of the wires on 1 cm in the interval 1024-450, and the geometry of the weave of the second type of catalytic grids characterized by the number of twists of the wires on 1 cm2in the range of 400-200.
The figure schematically shows the package the platinum wire catalyst, in which the height of sequentially alternating the two types of nets.
The platinum wire catalyst formed from two sequential types of catalytic grids, allowed to realize a number of benefits of technological and economic nature in comparison with the commonly used up to the present time homogeneous packages platinum mesh catalysts for the conversion of ammonia formed from catalytic grids of the same type.
These advantages described above technical solutions are illustrated below by examples. Comparative experiments were carried out in conditions of the pilot reactor has the following characteristics: the concentration of ammonia in the air 10 vol.%, the linear flow velocity of 0.5 m/s, inlet temperature 20°used in weaving experienced mesh wire with cross-sectional diameter 0,092 mm made of standard alloy SP (an alloy of platinum with palladium, rhodium and ruthenium), the platinum catalyst package was formed from six layers stacked catalytic nets.
Example 1 (produce the RNA package formed according to the scheme of the prototype).
Catalyst package consists of six identical grids with the number of twists of the wires on 1 cm2- 1024 (32×32 wire 1 cm). Obtained in the experiment, the conversion of ammonia was 92%.
Catalyst package consists of six nets of two different types: three grid of the first type, having the number of twists of the wires on 1 cm2- 1024, successively alternate with three grids of the second type having a number of twists on 1 cm2- 400 (20×20 wires 1 cm). Obtained in the experiment, the conversion of ammonia was 96%, 4% higher than in the experiment according to the scheme of the prototype. The mass of platinum in the generated according to the scheme of the invention the catalyst package is almost 20% less than the packet generated according to the scheme of the prototype (see Example 1).
Catalyst package consists of six nets of two different types: three grid of the first type, having the number of twists of the wires on 1 cm2- 450 (45×10 wires 1 cm), successively alternate with three grids of the second type having a number of twists on 1 cm2- 200 (20×10 wires 1 cm). Obtained in the experiment, the conversion of ammonia was 93%, 1% higher than in the experiment according to the scheme of the prototype. The mass of platinum in the generated according to the scheme of the invention the catalyst package is one third less than in the package, SF is mirovnom scheme of the prototype (see Example 1).
Thus, described the platinum wire catalyst formed in the form of a catalytic package of layers stacked two different geometric weave types catalytic nets, alternating the height of the package, allows you to increase the conversion of ammonia and reduce the attachment of platinum in the processes including process flow catalytic conversion of ammonia compared to traditional homogeneous type grids platinum catalyst grid service, which is the prototype of the present invention.
The present invention can be used in chemical industry for production of chemical products in all technological schemes, including catalytic conversion of ammonia.
The platinum wire catalyst for the conversion of ammonia formed in the form of a catalytic package of layers stacked catalytic wire mesh, woven wire with a diameter of 0.06 to 0.1 mm, consisting of alloys of platinum with rhodium, palladium, ruthenium, and other metals of the platinum group, characterized in that the catalytic package consists of two different geometric weave types of grids sequentially alternating the height of the package, the geometry of the weave of the first type of catalytic grids characterized by the number of weaves about oloc on 1 cm 2in the interval 1024-450, and the geometry of the weave of the second type of catalytic grids characterized by the number of twists of the wires on 1 cm2in the range of 400-200.
FIELD: chemical industry; method of intensification of the installations for production of the non-concentrated nitric acid.
SUBSTANCE: 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.
EFFECT: the invention allows to realize the intensification of the installations using already existed equipment, to reduce production cost and the specific consumption of the steam and the natural gas.
4 cl, 2 ex, 2 tbl, 2 dwg
FIELD: methods and devices for supporting of the catalytic meshes in the burners for oxygenation of ammonia.
SUBSTANCE: 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.
EFFECT: the invention ensures 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.
12 cl, 2 dwg, 2 tbl
FIELD: inorganic compounds technologies.
SUBSTANCE: 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.
EFFECT: increased yield of desired products.
4 cl, 6 ex
FIELD: initiating ammonia conversion reaction.
SUBSTANCE: 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.
EFFECT: reduction of time required for reaction over entire surface of catalyst; reduction of explosion danger.
2 cl, 10 ex
FIELD: chemical industry.
SUBSTANCE: 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.
EFFECT: the invention ensures high activity, selectivity and stability of the catalyst to thermocycles at its use in two-stage catalytic system with a decreased loading of platinoid screens.
8 cl, 1 tbl, 5 ex
FIELD: chemical industry; production of nitric acid.
SUBSTANCE: 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.
EFFECT: the invention ensures simplification of the method, decreased investments and specific consumption of fuel.
4 cl, 1 dwg
FIELD: composition and structure of composite metal semiconductor meso-porous materials; titanium-dioxide-based catalyst for photo-chemical reactions.
SUBSTANCE: proposed catalyst is meso-porous titanium-dioxide-based material containing crystalline phase of anatase in the amount no less than 30 mass-% and nickel in the amount no less than 2 mass-%; material has porous structure at average diameter of pores from 2 to 16 nm and specific surface no less than 70 m2/g; as catalyst of photo-chemical reaction of liberation of hydrogen from aqua-alcohol mixtures, it ensures quantum reaction yield from 0.09 to 0.13. Method of production of such catalyst includes introduction of precursor - titanium tetraalkoxyde and template of organic nature, holding reagent mixture till final molding of three-dimensional structure from it at successive stages of forming sol, then gel, separation of reaction product and treatment of this product till removal of template; process is carried out in aqua-alcohol solvent containing no more than 7 mass-% of water; at least one of ligands is introduced into solvent as template; ligand is selected from group of macro-cyclic compounds containing no less than four atoms of oxygen and/or from complexes of said macro-cyclic compounds with ions of metals selected from alkaline or alkaline-earth metals or F-metals containing lithium, potassium, sodium, rubidium, cesium, magnesium, calcium, strontium, barium, lanthanum and cerium; mixture is stirred before forming of sol maintaining its temperature not above 35°C till final molding of three-dimensional structure from reagent mixture; mixture is held in open reservoir at the same temperature at free access of water vapor; after removal of template from three-dimensional structure, mixture is first treated with nickel salt solution during period of time sufficient for withdrawal of nickel ions from solution by pores of structure, after which is it kept in hydrogen-containing medium during period of time sufficient for reduction of nickel ions in pores of structure to metallic nickel.
EFFECT: enhanced sorption and photo-catalytic parameters; reproducibility of catalyst properties.
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
FIELD: catalyst preparation methods.
SUBSTANCE: invention relates to a method for preparing catalyst and to catalyst no honeycomb-structure block ceramic and metallic carrier. Preparation procedure includes preliminarily calcining inert honeycomb block carrier and simultaneously applying onto its surface intermediate coating composed of modified alumina and active phase of one or several platinum group metals from water-alcohol suspension containing, wt %: boehmite 15-30, aluminum nitrate 1-2, cerium nitrate 4-8, 25% ammonium hydroxide solution 10-20, one or several precipitate group metal salts (calculated as metals) 0.020-0.052, water-to-alcohol weight ratio being 1:5 to 1:10; drying; and reduction. Thus prepared catalyst has following characteristics: specific coating area 100-200 m2/g, Al2O3 content 5-13%, CeO2 content 0.5-1,3%, active phase (on conversion to platinum group metals) 0.12-0.26%.
EFFECT: simplified technology due to reduced number of stages, accelerated operation, and high-efficiency catalyst.
5 cl, 1 tbl, 10 ex
FIELD: catalyst preparation methods.
SUBSTANCE: method involves preparing porous carrier and forming catalyst layer by impregnation of carrier with aqueous solution of transition group metal salts followed by drying and calcination. Porous catalyst carrier is a porous substrate of organic polymer material: polyurethane or polypropylene, which is dipped into aqueous suspension of powdered metal selected from metals having magnetic susceptibility χ from 3.6·106 to 150·106 Gs·e/g: iron, cobalt, chromium, nickel, or alloys thereof, or vanadium and polyvinylacetate glue as binder until leaving of air from substrate is completed, after which carrier blank is dried at ambient temperature and then fired at 750°C in vacuum oven and caked at 900-1300°C. Caked blank is molded and then subjected to rolling of outside surface to produce carrier having variable-density structure with density maximum located on emitting area. Formation of catalyst layer is achieved by multiple impregnations of the carrier with aqueous solution of acetates or sulfates of transition group metals: iron, cobalt, chromium, nickel, or alloys thereof in alternative order with dryings at ambient temperature and calcinations to produced catalyst bed 50-80 μm in thickness. In another embodiment of invention, formation of catalyst layer on carrier is accomplished by placing carrier in oven followed by forcing transition group metal carbonate vapors into oven for 60-120 min while gradually raising oven temperature to 850°C until layer of catalyst is grown up to its thickness 50-80 μm.
EFFECT: improved quality of catalyst and reduced its hydrodynamic resistance.
8 cl, 1 tbl, 3 ex
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to technology for preparing caprolactam by the cyclization reaction of derivatives of aminocaproic acid. Method is carried out by cyclizing hydrolysis of compound chosen from the group comprising aminocaproic acid esters or amides, or their mixtures. The process is carried out in the presence of water, in vapor phase at temperature 200-450°C in the presence of a solid catalyst comprising of aluminum oxide that comprises at least one macroporosity with pores volume corresponding to pores with diameter above 500 Å taken in the concentration 5 ml/100 g of above. Preferably, the specific square of catalyst particles is above 10 m2/g and the total volume of pores is 10 ml/100 g or above wherein pores volume corresponds to pores with diameter above 500 Å is 10 ml/100 g or above. Invention provides improving the process indices due to the improved properties of the solid catalyst.
EFFECT: improved preparing method.
5 cl, 2 ex
FIELD: catalyst preparation.
SUBSTANCE: invention relates to supported catalysts and provides a method for preparing catalyst-containing solid product comprising step, wherein ceramic carrier is applied onto metallic surface, and depositing catalytically active material onto ceramic carrier, which was preliminarily coated with supporting porous metallic material, ceramic carrier being applied onto and/or into supporting porous metallic material. Invention also describes device used in preparation of catalyst-containing solid product for applying supporting porous material onto inside or outside metallic surfaces of the hollow body.
EFFECT: increased stability of catalyst.
7 cl, 2 dwg
FIELD: chemical industry; trapping nitric oxides and other harmful substances from the waste gases.
SUBSTANCE: the invention is pertaining to chemical industry and is used for trapping nitric oxides and other harmful substances from the waste gases. The offered reactor contains a body with the connection pipes for introduction of the initial reactants. Inside the body there is a modular catalyst of a cellular structure. The through channels of the catalyst in respect to the incoming stream are oriented at an angel of 90°. The hydraulic diameter of the through channels of the different geometrical shape, beginning from the first channel, along the stream run is monotonically enlarging, reaching the ratio of the hydraulic diameters of the last channel to the first one first channel of no more than 1.5. No more than 1/6-th of the height from the bottom of the block the modular catalyst of the cellular structure has a mesh-cellular structure with a mesh size from 1.5 up to 3 mm and a specific surface up to 8...10 m2/g. The given engineering solution ensures an increased access to the internal surface of the bottom part of the modular catalyst of the cellular structure and its complete participation in operation.
EFFECT: the invention ensures an increased access to the internal surface of the bottom part of the modular catalyst of the cellular structure and its complete participation in operation.
FIELD: production of non-metallic elements.
SUBSTANCE: reactor comprises means for supplying hydrocarbon raw material and water vapor, means for discharging the product, and porous metallic load-bearing structure that receives catalyzer of reforming with water vapor. The porous load-bearing metallic structure is secured to the inner wall of the reactor by means of gluing or diffusion bounding.
EFFECT: improved functional capabilities.
5 cl, 2 dwg
FIELD: heterogeneous catalysts.
SUBSTANCE: catalyst contains porous carrier, buffer layer, interphase layer, and catalytically active layer on the surface wherein carrier has average pore size from 1 to 1000 μm and is selected from foam, felt, and combination thereof. Buffer layer is located between carrier and interphase layer and the latter between catalytically active layer and buffer layer. Catalyst preparation process comprises precipitation of buffer layer from vapor phase onto porous carrier and precipitation of interphase layer onto buffer layer. Catalytic processes involving the catalyst and relevant apparatus are also described.
EFFECT: improved heat expansion coefficients, resistance to temperature variation, and reduced side reactions such as coking.
55 cl, 4 dwg
FIELD: gas treatment catalysts.
SUBSTANCE: invention, in particular, relates to internal combustion engine exhaust gas neutralizers. Method of invention comprises rolling refractory metallic tape into block by way of overlapping its smooth and corrugated sides to form channels, performing ultrasound-assisted chemical cleaning of thus rolled tape in alkali solution followed by joining alternate layers of metallic tape with each other by diffusion welding in vacuo within a range of 5·10-5-1·10-5 mm Hg using stepwise heating to 1250 ± 10°С and isothermal exposure to this temperature for 12-17 min to form monolithic structure consisting of triangular and trapezoidal channel at density up to 600 channels per 1 inch2. Invention further describes carrier for catalytic exhaust gas neutralizers representing monolithic metallic structure in the form of cylindrical block or block with oval cross-section, which block consists of parallel channels, 200-600 per 1 inch2, density of channels varying along the cross-section of carrier: from center and extending to 0.55 0,7 diameter if cylindrical block or large axis of oval cross-section, density of channels is 400-600 per 1 inch2 and farther it decreases to 200 or 400 channel/inch2, respectively.
EFFECT: simplified manufacture technology and increased strength of monolithic cellular structure.
4 cl, 4 dwg, 1 tbl
FIELD: gas treatment catalysts.
SUBSTANCE: invention provides catalyst consisted of inert carrier and catalytic coating containing platinum, rhodium, and oxide substrate, wherein catalytic coating includes: (i) at least one first substrate material selected from group consisted of first active aluminum oxide enriched with cerium oxide; mixed oxide, which is cerium oxide/zirconium dioxide; and zirconium dioxide component; provided that catalytic component in at least one first substrate material is first portion of the total quantity of catalyst platinum, wherein concentration of the first portion of the total quantity of catalyst platinum lies within a range of 0.01 to 5.0% of the total mass of catalyst-containing materials; and (ii) a second substrate material containing second portion of total quantity of platinum and rhodium as catalytic component, said second substrate material being second active aluminum oxide, wherein concentration of platinum plus rhodium on the second substrate material lies within a range of 0.5 to 20% of the total mass of the second substrate material. Method for preparing above catalyst is also provided.
EFFECT: increased catalytic activity and reduced catalyst preparation expenses.
17 cl, 3 dwg, 5 tbl, 3 ex