Method of nitric acid production and an installation for production of nitric acid

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

 

The invention relates to the production of nitric acid obtained by the oxidation of ammonia by oxygen and absorption (absorption) of nitrogen oxides with water in aggregates with uniform pressure on the stages of the oxidation of ammonia and absorption of nitrogen oxides. The scope of the invention are units with uniform pressure of 0.7-1.0 MPa and the compression of air in the compressor part of the gas turbine installation. In the gas turbine installation engine air compressor is the recuperation of the gas turbine, in which the expanding heated to high temperature exhaust tail gases after the stage of absorption, and heating is provided by burning fuel, mainly natural gas in the combustion chamber of the turbine by mixing the tail gas with flue gases from a combustion chamber of the turbine.

A method of producing nitric acid under the same pressure (see, for example, the monograph “the Production of nitric acid in the units of great power” edited Vmelilo, M.: Chemistry, 1985, p.94-208), in which atmospheric air is compressed to the final pressure 0,716 MPa in two stages of compression. Atmospheric air at the first stage of compression is compressed in the axial compressor to pressure 0,343 MPa and temperature 174°, then cooled to 42° in the water heat exchanger, after which it goes to the 2nd stage compression in Central iny compressor, where is compressed to 0,716 MPa, heated up to 135°. The compressed air is separated into two streams: the main production of nitric acid, not primary - for own needs.

A large part of the primary air flow is directed to the mixture with gaseous ammonia, the other, smaller part is used for purging of nitric acid and as an additional air absorption. In accordance with the balance of primary air flow to maintain the stage of oxidation of ammonia optimal temperature (900° (C)the air before mixing with ammonia fuel from 135 to 180-230°With nitrous gases. The air in the starting the combustion turbine is supplied at a temperature of 135°C.

A prototype of the proposed method of production of nitric acid obtained by the oxidation of ammonia by oxygen and absorption of nitrogen oxides with water in aggregates with uniform pressure on the stages of the oxidation of ammonia and absorption of nitrogen oxides, is the method described in “Handbook apothica”, ed. 2nd, book 2-I, M.: Chemistry, 1987, p.66-73.

The disadvantages of the known methods can be attributed to the presence of two stages of compression of the air, resulting in additional hardware required to implement the second stage of compression and intermediate cooling.

In the same sources of information (see “the nitric acid unit is x high power” Ed. Vmelilo, M.: Chemistry, 1985, p.94-208 and the Directory of apothica”, ed. 2nd, book 2-I, M.: Chemistry, 1987, p.66-73) describes the units for the production of nitric acid obtained by the oxidation of ammonia by oxygen and absorption of nitrogen oxides with water in aggregates with uniform pressure on the stages of the oxidation of ammonia and absorption of nitrogen oxides, comprising a gas turbine installation with an axial air compressor and gas turbine on the same shaft, the cooling coil, centrifugal blower, starting motor-generator and a multi-stage gearbox that transmits the power from the gas turbine for rotation of the centrifugal blower and the energy from the motor-generator with a capacity of 800 kW at the start and to the motor-generator in a stationary mode.

Complex design of the gas turbine installation dramatically complicates the operation of the unit especially because of the frequent failure of the cooler, gearbox. In addition, increases the cost of the resulting nitric acid due to the cost of repairs and spare parts and a long period of start gas turbines leads to excessive fuel consumption - natural gas.

The proposed invention solves the problem of considerable simplification of the received compressed air to the desired pressure due to the exclusion of the air cooler, centrifugal compressor, multistage re is octora, and thereby simplify the whole method and installation nitric acid production, reducing capital investment, improve equipment reliability, in addition, reduction in the consumption of cooling water and, as a consequence, the water cycle, as well as a reduction in specific fuel consumption.

To solve this problem and obtain such technical result in the proposed method of production of nitric acid obtained by the oxidation of ammonia by oxygen and absorption of nitrogen oxides with water in aggregates with uniform pressure on the stages of the oxidation of ammonia and absorption of nitrogen oxides in the air is compressed to a single final pressure carried out continuously in a single stage without intermediate cooling, and then compressed and thus heated air is divided into two streams, one of which is designed to produce nitric acid, direct the cooled and then mixed with ammonia, and the other is fed directly into the combustion chamber of the fuel associated with recovery turbine.

Distinctive features of the proposed method lies in the implementation of the compression of the air in one step without intermediate cooling and subsequent separation of compressed air into two streams, one of which is designed to produce nitric acid, direct the cooled and then mixed with ammonia, and the other is fed directly into the combustion chamber of the fuel, associated with recovery turbine.

The essential features of the claimed method can significantly simplify the process of obtaining compressed air, and the subsequent cooling of the main flow of the compressed air expands the supply of air for mixture with ammonia at the optimum temperature (above 180-230°C), especially at a pressure of 0.8-1.0 MPa with lower capital costs and with the best rates on specific steam production.

To solve this problem and achieve the mentioned technical result of the proposed design solution unit with the apparatus of the oxidation of ammonia by air, the absorption of nitrogen oxides, the gas turbine installation including a compressor for compressing air and heat recovery turbine for expansion of the tail gas, the heated gases from the combustion of fuel, as well as the heater and mixer ammonia, line feed water for a boiler having parosbornoj, and purge the column of nitric acid, in which the gas turbine installation as a compressor for compressing air used axial compressor mounted directly on the same shaft with recovery turbine, and whose output from the compressor line to the compressed air stream is divided into two parts, one of which is designed to produce nitric acid, include the first and with the cooler compressed air and then with a mixer of ammonia with air, and the second is designed to burn fuel directly to the combustor recuperator turbine. In addition, as the cooler compressed air used “boiling” economizer connected to the line of feed water for boiler and paromomycin boiler line steam-water mixture, and the air line designed to produce nitric acid, is connected to the purge column nitric acid through the heater ammonia.

In contrast to the known constructive solutions offers claimed as a compressor for compressing air to use axial compressor mounted directly on the same shaft with the recuperation turbine with the compressor outlet line of the compressed air stream is divided into two parts, one of which is designed to produce nitric acid, associated first with the cooler compressed air and then with a mixer of ammonia with air, and the second designed for burning fuel directly to the combustion chamber of the regenerative turbine. In addition, as the cooler compressed air is suggested to use the “boiling” economizer connected to the line of feed water for boiler and paromomycin boiler line steam-water mixture, and also the line, intended for the floor the treatment of nitric acid, to connect with the purge column nitric acid through the heater ammonia. As “boiling” of the economizer can be used in the economizer, is given in the publication, for example, “New Polytechnical dictionary”, edited by Wailing, M., 2000, p.80.

The essential features of the claimed design solutions unit can simplify the design. The use of “boiling” economizer allows you to utilize low-grade heat hot air in the unit of nitric acid with the greatest efficiency, as it provides an increase steam generation.

Thus, the technical solution according to the invention allow not only to compensate for the increased energy consumption for air compression in one step, but to get some reduction in fuel consumption per ton of nitric acid, also taking into account the exception of the coolant water flow of cooling air between steps.

The invention is illustrated in the drawing, which schematically shows the aggregate production of nitric acid.

A unit for the production of nitric acid includes filter atmospheric air 1, the axial air compressor 2, “boiling” economizer 3, the mixer 4, the contact device 5, boiler 6, with parosbornoj 7, the combustion of the fuel 8, associated with PE is operacionnoi turbine 9, the tail gas heater 10, the catalytic purification reactor 11, the cooler-condenser 12, an absorption column 13, the purge column 14, the ammonia gas heater 15, the starter motor 16 to start the recuperation turbine 9.

The proposed method is carried out in the following sequence: the air, such as air, passing through the filter 1, is fed to the absorption axis of the air compressor 2, where it is compressed, and the compression to the end of the single pressure carried out continuously in a single stage of compression, and then compressed and thus heated air is divided into two streams, one of which is designed to produce nitric acid, direct cooling, for example, in “boiling” economizer 3 and then mixed with ammonia in the mixer 4, and the other is fed directly into the combustion chamber fuel 8 associated with recuperation turbine 9.

Thus the unit with a uniform pressure on the stages of the oxidation of ammonia and absorption of nitrogen oxides to nitric acid obtained by oxidation of ammonia with oxygen and absorption (absorption) of nitrogen oxides with water, works as follows. Atmospheric air passing through the filter 1, is fed to the suction of the air compressor 2, where the compression process. Compressed to the final uniform pressure of 0.7-1.0 MPa air, when heated is gatii to 280-360° With, is divided into two threads: the main thread that is designed to produce nitric acid enters the “boiling” economizer 3, which is cooled to 200-240°feed water with an initial temperature of 104°it is heated to the boiling temperature corresponding to the pressure of the steam generated in the HRSG 6, and boil the contents of the steam in the steam emulsion is discharged into parosbornoj 7 boiler 6 is not higher than 25%. The second stream (up to 15% of the total) without cooling flows into the combustion chamber 8, in which the tail gases are heated up to 500-750°due to the heat of combustion of natural gas and fed to the heat recovery turbine 9. The main stream of air after cooling is supplied to the mixer 4, which is heated in the heater 15 ammonia, ammonia-air mixture in the contact device 5, where the temperature 900-930°With ammonia is oxidized to nitrogen oxides. Nitrous gases are cooled in the exhaust-heat boiler 6 to 390-350°and act in the tail gas heater 10, which is heated to 260-280°and then the catalytic purification reactor 11; purified from nitrogen oxides in the tail gases are in recuperation turbine 9, the pre-heated in the combustion chamber fuel 8. Oxides of nitrogen, cooled to 150-180°come in the cooler-condenser 12 and then in the absorption column 13. Products : the traditional nitric acid rap from dissolved nitrogen oxides in the purge column 14, which is air cooled from 200-230°With up to 130-160°With the ammonia gas heater 15. To start the gas turbine installation is the starter 16.

1. Method for the production of nitric acid from ammonia by oxidation of ammonia with oxygen and absorption of nitrogen oxides with water in the unit with a single pressure stages of the oxidation of ammonia and absorption of nitrogen oxides using compressible in the production process of the air and products of combustion generated in the combustion chamber associated with recovery turbine, characterized in that the air is compressed to a single final pressure carried out continuously in a single stage of compression, and then compressed and thus heated air is divided into two streams, one of which is designed to produce nitric acid, direct the cooled and then mixed with ammonia, and the other is fed directly into the combustion chamber associated with recovery turbine.

2. A unit for the production of nitric acid from ammonia by oxidation of ammonia with oxygen and absorption of nitrogen oxides with water in the unit with a single pressure stages of the oxidation of ammonia and absorption of nitrogen oxides containing apparatus oxidation of ammonia by air, the absorption of nitrogen oxides, the gas turbine installation including a compressor for compressing air, the heat recovery turbine for expansion of the tail gas, the heated gases from the combustion chamber, fuel and air mixer of ammonia and its heater, the line of feed water for a boiler having parosbornoj, and the purge column nitric acid, characterized in that the gas turbine installation as a compressor for compressing air using axial compressor mounted directly on the same shaft with the recuperation turbine and the compressor outlet line of the compressed air stream is divided into two parts, one of which is designed to produce nitric acid, associated first with the cooler compressed air and then with mixer ammonia, and the second, designed for burning fuel directly to the combustion chamber of the regenerative turbine.

3. A unit for the production of nitric acid from ammonia according to claim 2, characterized in that as the cooler compressed air use "boiling" economizer connected to the line of feed water for boiler and paromomycin boiler line steam-water emulsion.

4. A unit for the production of nitric acid from ammonia according to claim 2, characterized in that the air line designed to produce nitric acid, is connected to the purge column nitric acid through the heater ammonia.



 

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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

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