A method of obtaining a concentrated nitrogen oxide (ii)

 

(57) Abstract:

The invention relates to the field of technology for hydroxylamine sulfate production and can be used in the manufacture of caprolactam. A method of obtaining a concentrated nitrogen oxide (II) includes steam-oxygen oxidation of ammonia, a mixture of hydrogen with nitrous gas, the hydrogenation of oxygen nitrous gas in homogeneous conditions in the gas phase at 600-1100oWith regenerative cooling nitrous gas, condensation of the water vapor emitting a concentrated nitrogen oxide (II), and the mixture of hydrogen and nitrous gas is carried out in 2 or more stages, the first stage of mixing serves to 90% of the total number of hydrogen. The method allows to increase the efficiency of the process, reduce the cost of equipment and materials, to increase the production of energy carrier (pair) by 3%, to increase annual production of concentrated nitric oxide (II) and, accordingly, has synthesis 1.3 times. 2 C. p. F.-ly, 2 ill., table 1.

The invention relates to the chemical industry, to technology for hydroxylamine sulfate production and can be used in the manufacture of caprolactam.

A method of obtaining kontsentrirovanie nitrous gas, condensation of water vapor from nitrous gas (Patent Germany 1224715, 1976, IPC 01 21/26).

This method is characterized (up 16%) losses of nitrogen oxide (II) at the stage of condensation of the formed 1820% and 1% solutions of nitric acid, because it does not include phase hydrogenation of oxygen nitrous gas, i.e., removal of excess oxygen from the nitrous gas after stage steam-oxygen oxidation of ammonia to prevent loss of nitric oxide.

Closest to the claimed technical essence and the achieved effect is a method of obtaining a concentrated nitrogen oxide (II), including the catalytic steam-oxygen oxidation of ammonia, the mixture obtained nitrous gas with hydrogen, the catalytic hydrogenation of oxygen nitrous gas, regenerative cooling nitrous gas, condensation of water vapor from nitrous gas with formation of a solution containing 1.0% by weight. HN3. This catalytic hydrogenation of oxygen nitrous gas is carried out in the reactor at the silver-manganese catalyst at 400-450o(Patent of the Russian Federation 2032613, 1995, IPC 01 21/26).

This method of obtaining a concentrated nitrogen oxide (II) PTY loss of nitric oxide (II) at the stage of condensation of the water vapor formed with a 1.0% solution of nitric acid.

The disadvantages of the known technical solutions should include the use for the hydrogenation of oxygen nitrous gas is expensive, scarce silver-manganese catalyst, the presence of the device for placement of the catalyst and, as a consequence, high aerodynamic resistance technological tract.

The problem to which the invention is directed, is to increase the efficiency of the method of obtaining a concentrated nitrogen oxide (II) by applying the homogeneous hydrogenation of oxygen nitrous gas was found for the given process conditions, which gives the possibility to exclude from the technology of expensive catalyst containing precious metal, as well as the apparatus in which the catalyst (hydrogenation reactor), while known technological parameters of the process, as well as the technical result, which is expressed as a reduction in the material intensity of the process in General, increasing the production of concentrated nitric oxide and steam, the reduction of the aerodynamic resistance of the technological path.

The inventive method has the following essential features:

- hydrogenation of oxygen nitrous gas is carried out in hemoglobin temperature 600-1100oC;

- the mixing of hydrogen with nitrous gas is carried out in two or more stages;

- on the first step of mixing hydrogen with nitrous gas serves to 90% of the total number of hydrogen.

In the present method in comparison with the known method of obtaining a concentrated nitrogen oxide (II) (prototype), including the catalytic steam-oxygen oxidation of ammonia, a mixture of hydrogen with nitrous gas, catalytic hydrogenation of oxygen nitrous gas, regenerative cooling nitrous gas and condensation of water vapor, has the following significant differences: the hydrogenation of oxygen nitrous gas conducting homogeneous when the selected conditions - temperature 6001100oC, and the mixture of hydrogen and nitrous gas is carried out in two or more stages with intermediate regenerative cooling nitrous gas. At the first stage of mixing hydrogen with nitrous gas serves to 90% of the total number of hydrogen.

The proposed solution allows to exclude from technological scheme of the reactor hydrogenation with expensive silver-manganese catalyst operated in the temperature range up to 450oC.

Homogeneous Gadirov and hydrogen with nitrous gas, allows you to get at the stage of condensation of water vapor solution of nitric acid containing not more than 1.0 wt.%. HNO3and a concentrated nitrogen oxide (II) is of the same quality as in the case of catalytic hydrogenation, i.e., by the known technical solution. Due to increased temperature on the boiler elements reactors from 1100oWith up to 160oCompared to the prototype (from 950o300oC) increases by 3% production of high-grade steam. In addition, an additional technical result of the proposed method is the reduction of not less than 2 times the aerodynamic drag on the main gas stream due to the exclusion of the technological scheme of silver-manganese catalyst and the hydrogenation reactor, which allows to increase the production of concentrated nitric oxide (II) and has synthesis respectively not less than 1.3 times.

Comparative analysis of the proposed technical solution with the prototype shows that the proposed method offers the new procedure, technological operations and techniques, allowing to carry out the process in another apparatus different from the known process conditions. Thus, saleemullah the principal technological scheme of production of concentrated nitric oxide (II), presented on Fig. 1, and data confirming the existence of a positive effect and are summarized in table 1. Technological scheme for obtaining a concentrated nitrogen oxide (II) the prototype are presented for comparison in Fig.2.

The inventive method of obtaining a concentrated nitrogen oxide (II) is as follows: the reaction mixture containing ammonia, oxygen and water vapor, is directed into the reactor oxidation of ammonia 1, where the platinum catalyst grids at a temperature of 900-950oC and a pressure of 0.10-0.15 MPa ammonia is oxidized to nitric oxide (II). To achieve maximum conversion of ammonia into nitric oxide (II) maintain a ratio of ammonia/oxygen at 8-10% above stoichiometric. The formed nitrous gas contains, in addition to nitric oxide (II), water vapor, nitrous oxide (I), the excess of unreacted oxygen. With the aim of obtaining the maximum amount of nitrogen oxide (II) the required quality oxygen nitrous gas hydronaut in homogeneous conditions at a temperature of 600-1100oWith the stoichiometric quantity of hydrogen. The mixture of hydrogen and nitrous gas is carried out in two or more stages with intermediate regenerative cooling narodnog the total amount of hydrogen. Hydrogenation of excess unreacted oxygen nitrous gas prevents oxidation of NO to NO2and the subsequent formation of nitric acid in the condensate in the condenser-desorber 3.

Step homogeneous hydrogenation of excess oxygen nitrous gas is carried out in a temperature zone 600-1100oWith regenerative cooling nitrous gas to 160oWith and elaboration of additional process steam. Next, nitrous gas enters the site, dividing it into nitric acid condensate and concentrated nitric oxide (II), coming from the condenser 4 later in the technological process of production has synthesis.

The degree of hydrogenation of oxygen, defined as the ratio of the amount of oxygen that reacted in the reaction of hydrogenation, the amount of oxygen in nitrous gas to the reaction of hydrogenation (to supply hydrogen nitrous gas) is 92%, with the degree of stabilization of nitrogen oxide (II) equal to not less than 96% (see table). The degree of stabilization of nitrogen oxide (II) determine the ratio of the content of nitrogen oxide (II) in nitrous gas after the process of hydrogenation to the number in the nitrous gas to feed them examples:

Example 1. In nitrous gas produced in the reactor for the oxidation of ammonia, part of NO - 13,10% vol., ABOUT2- 1,55% vol., H2About - to 84.70% vol., N2with 0.65% about. dispense hydrogen in stoichiometric ratio to the oxygen in nitrous gas, as2: H2= 1 : 2. The dosage of hydrogen is carried out in two stages with intermediate regenerative cooling nitrous gas. At the first stage of mixing hydrogen with nitrous gas serves 70% (0,7) of the total number of hydrogen, the second step of mixing the hydrogen serves in the amount of 30% (0,3), respectively. The process of hydrogenation is carried out in a reactor of the oxidation of ammonia in homogeneous conditions at a temperature of 900oC. to a Residual content of oxygen in nitrous gas after the process of hydrogenation is 0.12% vol., and the content of nitrogen oxide (II) is to 12.58%. Thus, the degree of hydrogenation of oxygen is:

< / BR>
and the degree of stabilization, respectively:

< / BR>
Example 2 (on prototype, Fig.2). Nitrous gas specified in example 1 composition is directed from the reactor for the oxidation of ammonia to 1 in the hydrogenation reactor oxygen 5, here dispense hydrogen at a ratio of 1:2 to the oxygen contained in nitros is tiravanija oxygen in this case is also 92%, when the degree of stabilization of nitrogen oxide (II) is 96%.

For additional examples, illustrating the presence of the proposed technical solution, the positive effect compared to the prototype, for clarity, are summarized in table.

As can be seen from the table, the proposed method produce a concentrated nitrogen oxide (II) provides conservation on the level of such technological parameters as the degree of hydrogenation of oxygen and the degree of stabilization of nitrogen oxide (II), that allows to exclude from technology silver-manganese catalyst and reactor hydrogenation of oxygen.

Thus, the essence of the invention lies in the fact that the proposed set of distinctive features of the method of obtaining a concentrated nitrogen oxide (II), including the hydrogenation of oxygen nitrous gas in homogeneous conditions at 600-1100oWith the mixture of hydrogen and nitrous gas in two or more stages and flow on the first stage of mixing hydrogen with nitrous gas up to 90% of the total number of hydrogen will help to improve the efficiency of the process by excluding from the operation of expensive silver-manganese catalyst and the hydrogenation reactor.

Dopolnitelnogo resistance on the main gas stream, it allows to increase the production of concentrated nitric oxide (II) and has synthesis respectively 1.3 times in comparison with the prototype.

The expected annual economic effect from implementation of the proposed technical solution in the manufacture of caprolactam in terms of Togliatti "KuibyshevAzot" will be not less than 100 thousand dollars.

1. A method of obtaining a concentrated nitrogen oxide (II), including the catalytic steam-oxygen oxidation of ammonia, a mixture of hydrogen with nitrous gas, the hydrogenation of oxygen nitrous gas, regenerative cooling nitrous gas, condensation of the water vapor emitting a concentrated nitrogen oxide (II), characterized in that the hydrogenation of oxygen nitrous gas is carried out in homogeneous conditions at 600-1100oC.

2. The method according to p. 1, characterized in that the mixture of hydrogen and nitrous gas is carried out in two or more steps.

3. The method according to p. 1, characterized in that the first stage of mixing hydrogen with nitrous gas serves to 90 % of the total number of hydrogen.

 

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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: 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

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2 cl, 10 ex

FIELD: inorganic compounds technologies.

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FIELD: methods and devices for supporting of the catalytic meshes in the burners for oxygenation of ammonia.

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12 cl, 2 dwg, 2 tbl

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.

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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.

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SUBSTANCE: 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.

EFFECT: increased catalyst activity.

8 cl, 2 tbl, 3 ex

FIELD: inorganic synthesis catalysts.

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

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

5 cl, 6 ex

FIELD: chemistry.

SUBSTANCE: 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.

EFFECT: obtaining catalysts with homogenous distribution of active phases and uniform and regulated porosity for optimisation of characteristics in catalytic applications.

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