A multi-level high-purity nitric acid co-production system and co-production method

Abstract

The present invention discloses a multi-level high-purity nitric acid co-production system and a co-production method thereof, including: the bottom of the heater is connected to the raw material delivery system, and the top of the heater is connected to the primary co-production unit through a connecting pipeline; the primary co-production unit includes a distillation tower unit, a self-blowing white heater and a cooling device, the bottom of the distillation tower unit is simultaneously connected to the connecting pipeline and the self-blowing white pipeline, and the top of the distillation tower unit is connected to the secondary co-production unit through a steam pipeline; the secondary co-production unit and the N-level co-production unit have the same structure as the primary co-production unit. The co-production system of the present invention does not introduce other substances, achieves the effect of low energy consumption and high purity, can not only realize the simultaneous continuous production or single continuous production of multiple products according to various needs, but also can adjust the output distribution according to needs, and has the characteristics of low input cost and production cost, simple and controllable operation, simultaneous and continuous production of multiple levels of products, and guaranteed product quality and output.

Description

Technical Field

[0001] The present invention relates to the technical field of nitric acid production, and in particular to a multi-level high-purity nitric acid co-production system and a co-production method thereof. Background Art

[0002] Nitric acid is a very important chemical raw material. It is a colorless liquid. Nitric acid can be mixed with water in any proportion to form concentrated nitric acid and dilute nitric acid. Concentrated nitric acid is mainly used in the national defense industry and is the main raw material for the production of TNT, nitrocellulose, and nitroglycerin. Most of the dilute nitric acid is used to make ammonium nitrate, nitrophosphate fertilizer, and nitrates. Industrially, the raw materials for the production of nitric acid are mainly ammonia and air. It is produced by ammonia contact catalytic oxidation, that is, under the action of a catalyst, ammonia is oxidized to nitric oxide, and nitric oxide is further oxidized to nitrogen dioxide, which is absorbed by water to form nitric acid. However, this method can only produce industrial-grade nitric acid, which contains more nitrogen dioxide and cannot meet high-end needs. For example, for electronic-grade nitric acid products, the purity requirements of electronic-grade nitric acid products are high, and the impurity content is required to be within ppb (10 -9 ) grade, and its preparation method is usually to heat nitric acid and water to evaporate into gas by distillation, and then cool and recover to obtain pure nitric acid. The existing electronic grade nitric acid production process can only achieve the production of electronic grade nitric acid products of a certain grade. The production system structure is complex, the operation is difficult, the product structure is single, the product quality and output are unstable, the adaptability is poor, and the production cost is high. These shortcomings lead to the high cost of electronic grade nitric acid products.

[0003] In order to overcome these problems, technicians have improved the existing electronic-grade nitric acid production system for many years and have also obtained some improved results. For example, CN115028147A discloses a process for continuously preparing electronic-grade nitric acid by an integrated method of distillation and stripping. The patent uses industrial-grade nitric acid as raw material. After distillation in a distillation tower, the material extracted from the top of the tower is condensed in a condenser, stripped with compressed air, and filtered by a filter to obtain G4-grade nitric acid. The material extracted from the upper part of the distillation tower is condensed in a condenser and filtered by a filter to obtain G2-grade nitric acid and G3-grade nitric acid, thereby realizing the production of multiple varieties of nitric acid. However, this production process can only realize the production of three varieties of nitric acid, with limited production capacity, and it is difficult to control the output of each variety of products. At the same time, it not only retains the existing compressed air stripping system, but also does not undergo stripping treatment for the G2 / G3-grade products produced, and its product quality and production cost need to be improved.

[0004] Chinese patent CN112591722A discloses a method for co-producing industrial-grade nitric acid and electronic-grade nitric acid. The patent can produce both industrial-grade nitric acid and electronic-grade nitric acid through a complex co-production system. The electronic-grade nitric acid product is single and cannot achieve multiple levels of continuous output. Chinese patent CN112279225A discloses a production system for co-producing electronic-grade nitric acid with industrial-grade nitric acid. Accordingly, the patent also integrates the industrial-grade nitric acid production process and the electronic-grade nitric acid production process. The resulting complex production system can only produce one level of electronic-grade nitric acid and cannot achieve multiple levels of continuous output. Summary of the invention

[0005] The purpose of the invention is to provide a multi-level high-purity nitric acid co-production system and a co-production method thereof in view of the above-mentioned problems. The invention designs a self-blowing structure, and designs multiple product outlets based on the structure. The self-blowing method not only eliminates the need for the setting of a compressed air system, but also does not introduce other substances into the entire production process, thereby achieving the effect of low energy consumption and high purity. The co-production system formed by combining the technical design can realize simultaneous continuous production or single continuous production of multiple products according to various needs, without setting product level restrictions, and the output distribution can be adjusted as needed. It has the characteristics of low investment cost and production cost, simple and controllable operation, simultaneous and continuous production of multiple levels of products, and guaranteed product quality and output, thereby overcoming the shortcomings of the existing electronic grade nitric acid production process.

[0006] The technical solution adopted by the present invention is as follows: a multi-level high-purity nitric acid co-production system, which comprises:

[0007] A heater, used to heat the nitric acid raw material into steam, the bottom of the heater is connected to the raw material conveying system, and the top of the heater is connected to the primary cogeneration unit through a connecting pipeline;

[0008] A primary co-production unit is used for heating the white nitric acid and obtaining a primary product. The primary co-production unit includes a distillation tower unit, a white nitric acid self-blowing heater and a cooling device. The bottom of the distillation tower unit is simultaneously connected to a connecting pipeline and a white nitric acid self-blowing pipeline, and the top of the distillation tower unit is connected to a secondary co-production unit through a steam pipeline; the distillation tower unit is connected to the top of the white nitric acid self-blowing heater through the white nitric acid self-blowing pipeline, the bottom of the white nitric acid self-blowing heater is connected to a liquid nitric acid pipeline, and the top of the liquid nitric acid pipeline is connected to the bottom of the white nitric acid self-blowing pipeline; the inlet of the cooling device is connected to the liquid nitric acid pipeline through a liquid discharge pipeline, the liquid outlet thereof is connected to a reactor, and the gas outlet thereof is connected to a tail gas absorption system;

[0009] The secondary co-production unit is used to heat the white nitric acid and obtain the secondary product. The structure of the secondary co-production unit is the same as that of the primary co-production unit. Similarly, the top of the distillation tower unit of the secondary co-production unit is connected to the steam pipeline, and the top of the distillation tower unit is connected in series to N-stage co-production units through the steam pipeline, wherein N=3, 4, 5,...N, and the structure of the N-stage co-production unit is the same as that of the primary co-production unit.

[0010] The N-level co-production unit is used to heat the white nitric acid and obtain the N-level product. The top of the distillation tower unit of the N-level co-production unit is connected to the tail gas absorption system.

[0011] In the present invention, industrial-grade nitric acid is heated by a heater, and the generated steam enters the distillation tower unit of the primary co-production unit. After the distillation tower unit rectifies and refluxes the nitric acid steam, the steam extracted from the top of the tower enters the secondary co-production unit, and the refluxed liquid nitric acid enters the self-blowing pipeline and enters the self-blowing heater through the liquid nitric acid pipeline. The self-blowing heater heats the liquid nitric acid to make it boil, and the generated steam is discharged into the self-blowing pipeline, thereby realizing the self-blowing of nitric acid. After the liquid nitric acid in the liquid nitric acid pipeline is full, the valve on the liquid discharge pipeline is opened, and the excess liquid nitric acid enters the cooling device through the liquid discharge pipeline, and enters the reactor after being cooled by the cooling device, so as to obtain AR / GR grade nitric acid product. Correspondingly, the steam entering the secondary co-production unit is treated with self-blowing to obtain G2 / G3 grade products. Similarly, the subsequent N-stage co-production units connected in series respectively obtain G3 / G4 grade products, G4 / G5 grade products, and G5 grade products. This achieves the effect of one system producing multiple different grades of products at the same time. In the entire system, only the heater and the self-blowing heater need to consume energy, and other equipment has no energy consumption. Very few production equipment are required, the production system is extremely simple and highly integrated, the manual operation is simple, the product quality and output are guaranteed, and the shortcomings of the existing electronic-grade nitric acid production process are overcome.

[0012] Furthermore, in order to allow the liquid nitric acid carried in the nitric acid vapor to flow back into the heater, a first packing layer is provided in the connecting pipeline. The first packing layer is located above the top of the heater and is used to flow the liquid nitric acid back into the heater.

[0013] Furthermore, in order to reflux the liquid nitric acid in the distillation tower into the self-blowing white pipeline, the distillation tower unit includes a distillation tower and a second packing layer located below the distillation tower, and the second packing layer is used to reflux the liquid nitric acid into the self-blowing white pipeline.

[0014] Furthermore, the cooling device includes at least one condenser (multiple groups of condensers are connected in series according to different product levels, and generally two condensers are sufficient), the inlet end of the condenser is connected to the liquid discharge pipeline, the liquid outlet end of the condenser is connected to the reactor, and the gas outlet of the condenser is connected to the exhaust gas absorption system.

[0015] Furthermore, in order to recover the heat source of the system, the raw material conveying system includes a raw material conveying pipeline, one end of the raw material conveying pipeline is connected to the raw material tank, and the other end is connected to the heater. The cooling device is connected in series to the raw material conveying pipeline so that the material in the cooling device can exchange heat with the raw material in the raw material conveying pipeline.

[0016] Furthermore, in order to recover the heat source of the system, a heat exchanger is provided in the self-blowing white pipeline, and the heat exchanger is connected in series to the raw material conveying pipeline to enable heat exchange between the material in the self-blowing white pipeline and the raw material in the raw material conveying pipeline.

[0017] Furthermore, a discharge valve is provided on the liquid discharge pipeline.

[0018] Furthermore, the exhaust gas absorption system includes a first exhaust gas absorption pipeline and a second exhaust gas absorption pipeline, one end of the first exhaust gas absorption pipeline is connected to the gas outlet of the cooling device, and the other end thereof is connected to the exhaust gas absorption device, and one end of the second exhaust gas absorption pipeline is connected to the gas outlet of the reactor, and the other end thereof is connected to the exhaust gas absorption device.

[0019] Furthermore, the present invention also includes a multi-level high-purity nitric acid co-production method, comprising the following steps:

[0020] A. The nitric acid raw material is transported to the heater through the raw material transport system, heated by the heater to form steam and enter the primary co-production unit. The primary co-production unit heats and blows the condensed nitric acid through the self-blowing heater, collects the primary product, and enters the secondary co-production unit through the steam of the distillation tower unit;

[0021] B. The secondary co-production unit heats and blows the condensed nitric acid through a self-blowing heater, and collects the secondary product. Similarly, the steam passing through the distillation tower unit enters the N-stage co-production unit in sequence, and obtains the tertiary product, the quaternary product,..., the N-stage product in sequence.

[0022] Furthermore, the output distribution of products at each level can be adjusted by adjusting the heating efficiency of the self-blowing white heaters of the co-production units at each level.

[0023] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0024] 1. The present invention heats nitric acid to generate steam to blow white nitric acid products. No blowing medium and impurities are introduced during the blowing process. Meanwhile, the nitric acid can be further purified, thereby improving the quality of the nitric acid and effectively reducing energy consumption. This provides a prerequisite for producing high-purity products. By performing rectification and blowing white on the nitric acid for different times, electronic-grade nitric acid products of different levels can be obtained. The continuous production of nitric acid products of various levels can be achieved in one production system, and all levels of electronic-grade nitric acid products can be produced simultaneously.

[0025] 2. Compared with the compressed air blowing process, the self-blowing process of the present invention does not introduce impurities, the energy consumption increment of the production system is small, and continuous blowing can be achieved, thus avoiding the problem of low production efficiency caused by intermittent blowing of compressed air;

[0026] 3. The present invention can not only continuously produce a variety of nitric acid products, but also adjust the types and outputs of nitric acid products according to production needs. By controlling the heating efficiency of the self-blowing white heater of the co-production unit, the output of nitric acid products obtained by each co-production unit can be changed, thereby realizing the selective production of some nitric acid products. It has strong adjustability and adaptability to production needs, low investment cost for enterprises, and can bring considerable economic benefits to enterprises. It is especially suitable for large-scale industrial production of nitric acid products. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of a multi-level high-purity nitric acid co-production system of the present invention;

[0028] Figure 2 It is a schematic diagram of the series structure of the primary co-production unit and the secondary co-production unit of the present invention;

[0029] Figure 3 It is a schematic diagram of the structure of the primary cogeneration unit of the present invention.

[0030] Markings in the figure: 1 is a primary cogeneration unit, 101, 201, 301, 401, 501 are distillation tower units, 102 is a self-blowing white heater, 103 is a cooling device, 104 is a connecting pipeline, 105 is a self-blowing white pipeline, 106 is a liquid nitric acid pipeline, 107 is a liquid discharge pipeline, 108, 203, 303, 403, 503 are reactors, 109 is a distillation tower, 110 is a second packing layer, 111 is a heat exchanger, 2 is a secondary cogeneration unit, 202, 302, 402 are steam pipelines, 3 is a tertiary cogeneration unit, 4 is a quaternary cogeneration unit, 5 is a quintuple cogeneration unit, 6 is a heater, 601 is a first packing layer, 7 is a raw material transportation system, 8 is a tail gas absorption system, 801 is a first tail gas absorption pipeline, 802 is a second tail gas absorption pipeline, and 9 is a raw material tank. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0033] like Figures 1 to 3 As shown, Figure 1 A multi-stage high-purity nitric acid co-production system with five-stage co-production units is shown, which includes:

[0034] The heater 6 is used to heat the nitric acid raw material into steam. The bottom of the heater 6 is connected to the raw material conveying system 7, and the top of the heater 6 is connected to the primary cogeneration unit 1 through the connecting pipeline 104;

[0035] The primary co-production unit 1 is used for heating the white nitric acid and obtaining the primary product. The primary co-production unit 1 comprises a distillation tower unit 101, a self-blowing heater 102 and a cooling device 103. The bottom of the distillation tower unit 101 is simultaneously connected to a connecting pipeline 104 and a self-blowing pipeline 105. The top of the distillation tower unit 101 is connected to a secondary co-production unit 2 through a steam pipeline 202.

[0036] The distillation tower unit 101 is used to condense and reflux the nitric acid vapor discharged from the heater 1. The distillation tower unit 101 is connected to the top of the self-blowing heater 102 through the self-blowing pipeline 105.

[0037] A self-blowing heater 102 is used to heat and blow nitric acid discharged from the distillation tower unit 101, the bottom of the self-blowing heater 102 is connected to a liquid nitric acid pipeline 106, and the top of the liquid nitric acid pipeline 106 is connected to the bottom of the self-blowing pipeline 105;

[0038] A cooling device 103 is used to cool the nitric acid discharged from the self-blowing heater 102. The inlet of the cooling device 103 is connected to the liquid nitric acid pipeline 106 through a liquid discharge pipeline 107, the liquid outlet is connected to the reactor 108, and the gas outlet is connected to the tail gas absorption system 8. The liquid discharge pipeline 107 is provided with a discharge valve (not shown);

[0039] The secondary co-production unit 2 is used for heating the white nitric acid and obtaining the secondary product. The structure of the secondary co-production unit is the same as that of the primary co-production unit. By analogy, the top of the distillation tower unit 201 of the secondary co-production unit 2 is connected to the steam pipeline 302, and the top of the distillation tower unit 201 is connected in series to the tertiary co-production unit 3 through the steam pipeline 302. The top of the distillation tower unit 301 of the tertiary co-production unit is connected to the steam pipeline 402, and the top of the distillation tower unit 301 is connected in series to the quaternary co-production unit 4 through the steam pipeline 402. The top of the distillation tower unit 401 of the quaternary co-production unit 4 is connected to the steam pipeline 502, and the top of the distillation tower unit 401 is connected in series to the fifth co-production unit 5 through the steam pipeline 502. The top of the distillation tower unit 501 of the fifth co-production unit 5 is connected to the tail gas absorption system 8.

[0040] In the above-mentioned co-production system, industrial-grade nitric acid is transported to the heater 6 through the raw material transportation system 7. Through the heating effect of the heater 6, the nitric acid is converted into steam and enters the distillation tower unit 101 of the primary co-production unit 1. After the distillation tower unit 101 rectifies and refluxes the nitric acid steam, the steam extracted from the top of the tower enters the secondary co-production unit 2, and the refluxed liquid nitric acid enters the self-blowing pipeline 105, and enters the self-blowing heater 102 through the liquid nitric acid pipeline 106. The self-blowing heater 102 heats the liquid nitric acid to make it boil, and the generated steam is discharged into the self-blowing pipeline 105, thereby realizing the self-blowing of the nitric acid. After the liquid nitric acid in the liquid nitric acid pipeline 106 is full, the valve on the liquid discharge pipeline 107 is opened, and the excess liquid nitric acid enters the cooling device 103 through the liquid discharge pipeline 107, and enters the reactor 108 after being cooled by the cooling device 103, to obtain AR / GR grade nitric acid product. Correspondingly, after the steam entering the secondary co-production unit 2 is treated with self-blowing, G2 / G3 grade products are obtained in the reactor 203 of the secondary co-production unit 2. Similarly, G3 / G4 grade products are obtained in the reactor 303 of the tertiary co-production unit 3, G4 / G5 grade products are obtained in the reactor 403 of the quaternary co-production unit 4, and G5 grade products are obtained in the reactor 503 of the quintuple co-production unit 5. Thus, one system is realized to simultaneously produce AR grade, G2 grade, G3 grade, G4 grade, and G5 grade nitric acid products.

[0041] In the above-mentioned co-production system, in order to allow the liquid nitric acid carried in the nitric acid vapor to flow back into the heater 6, a first packing layer 601 is provided in the connecting pipeline 104. The first packing layer 601 is located above the top of the heater 6. The first packing layer 601 is filled with glass rings to allow steam to pass through but not liquid.

[0042] As an embodiment, in order to reflux the liquid nitric acid in the distillation tower to the self-blowing white pipeline, the distillation tower unit 101 includes a distillation tower 109 and a second packing layer 110 located below the distillation tower 109, and the second packing layer 110 is used to reflux the liquid nitric acid to the self-blowing white pipeline 105. The second packing layer 110 is filled with glass rings or Raschig rings to allow steam to pass but not liquid. Accordingly, the distillation tower units of the co-production units at each level include a distillation tower and a second packing layer to improve the purification effect of the co-production system.

[0043] As an implementation method, taking the primary cogeneration unit 1 as an example, Figure 2 and Figure 3 As shown, the cooling device 103 of the primary cogeneration unit 1 includes two condensers (not shown), the inlet end of the condenser is connected to the liquid discharge pipeline 107, the liquid outlet end of the condenser is connected to the reactor 108, and the gas outlet of the condenser is connected to the tail gas absorption system 8. Of course, the condenser of the present invention is not limited to two, and it can be one, three, four, etc.

[0044] As an embodiment, in order to recover the heat source of the system, the raw material delivery system 7 includes a raw material delivery pipeline, one end of the raw material delivery pipeline is connected to the raw material tank 9, and the other end is connected to the heater 6. The cooling device 103 of the primary co-production unit 1 is connected in series to the raw material delivery pipeline, so that the material in the cooling device 103 and the raw material in the raw material delivery pipeline undergo heat exchange, and then the heat source can be recovered by using the industrial-grade nitric acid raw material as the heat exchange medium without using the heat exchange medium. Correspondingly, the cooling device (not shown) of the secondary co-production unit 2 is also connected in series to the raw material delivery pipeline, and then the heat source is further recovered. By analogy, the cooling devices of the co-production units at all levels can be connected in series to the raw material delivery pipeline, thereby realizing the heat source recovery of the cooling device of the entire co-production system. However, from the actual production point of view, after the three-stage co-production unit, the product flow rate is less, and the output of the entire co-production system is mainly concentrated in the primary co-production unit 1 and the secondary co-production unit 2. Therefore, the cooling devices of the primary co-production unit 1 and the secondary co-production unit 2 are mainly connected in series to the raw material delivery pipeline. Of course, in order to increase the output of other levels of products, the output distribution of each level of products can be adjusted by adjusting the heating efficiency of the self-blowing white heater of each level of co-production unit. At this time, the cooling device of the corresponding co-production unit can be connected in series to the raw material conveying pipeline to recover the heat source. Therefore, the series connection mode of the cooling device of the present invention is not limited to the primary co-production unit 1 and the secondary co-production unit 2.

[0045] As an improved implementation method, in order to recover further heat source of the system and give the self-purge pipeline 105 a condensation function, a heat exchanger 111 is provided in the self-purge pipeline 105. Figure 2As shown, the heat exchanger 111 is connected in series to the raw material conveying pipeline to exchange heat between the material in the self-blowing white pipeline 105 and the raw material in the raw material conveying pipeline, thereby further recovering the heat source and further condensing the nitric acid.

[0046] As an embodiment, the tail gas absorption system 8 of the present invention includes a first tail gas absorption pipeline 801 and a second tail gas absorption pipeline 802, one end of the first tail gas absorption pipeline 801 is connected to the gas outlet of the cooling device of each stage of the co-production unit to collect the tail gas in the cooling device through the first tail gas absorption pipeline 801, and the other end thereof is connected to the tail gas absorption device (existing device, not shown), one end of the second tail gas absorption pipeline 802 is connected to the gas outlet of the reactor of each stage of the co-production unit to collect the tail gas in the reactor through the second tail gas absorption pipeline 802, and the other end thereof is connected to the tail gas absorption device.

[0047] Furthermore, the present invention also includes a multi-level high-purity nitric acid co-production method, Figure 1 Taking the cogeneration system shown in the figure as an example, the following steps are included:

[0048] A. The nitric acid raw material is transported to the heater 6 through the raw material transport system 7, heated by the heater 6 to form steam and enter the primary co-production unit 1. The primary co-production unit 1 heats and blows the condensed nitric acid through the self-blowing heater 102, and collects it through the reactor 108 to obtain the primary product (AR / GR grade nitric acid). The steam extracted from the top of the distillation tower unit 101 enters the secondary co-production unit 2;

[0049] B. The secondary co-production unit 2 heats and blows the condensed nitric acid through a self-blowing heater (not shown), and collects the secondary product (G2 / G3 grade nitric acid). Similarly, the steam passing through the distillation tower unit successively enters the tertiary co-production unit 3, the quaternary co-production unit 4, and the quinary co-production unit 5, and successively obtains the tertiary product (G3 / G4 grade nitric acid), the quaternary product (G4 / G5 grade nitric acid), and the quinary product (G5 grade nitric acid).

[0050] As an implementation method, when only or mainly G2 / G3 grade nitric acid products are needed, at this time, the valve on the liquid discharge pipeline 107 of the primary co-production unit 1 is closed, the heating efficiency of the self-blowing heater 102 is increased, and all or most of the nitric acid in the self-blowing heater 102 is converted into nitric acid vapor, thereby increasing the nitric acid vapor flow entering the secondary co-production unit 2, thereby increasing the secondary product G2 / G3 grade nitric acid) output in the secondary co-production unit 2, and the output of the unnecessary lower-grade nitric acid product is controlled. By analogy, the desired grade of nitric acid products can be selectively produced.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-level high-purity nitric acid co-production system, characterized in that it include: A heater, used to heat the nitric acid raw material into steam, the bottom of the heater is connected to the raw material conveying system, and the top of the heater is connected to the primary cogeneration unit through a connecting pipeline; A primary co-production unit is used for heating the white nitric acid and obtaining a primary product. The primary co-production unit includes a distillation tower unit, a white nitric acid self-blowing heater and a cooling device. The bottom of the distillation tower unit is simultaneously connected to a connecting pipeline and a white nitric acid self-blowing pipeline, and the top of the distillation tower unit is connected to a secondary co-production unit through a steam pipeline; the distillation tower unit is connected to the top of the white nitric acid self-blowing heater through the white nitric acid self-blowing pipeline, the bottom of the white nitric acid self-blowing heater is connected to a liquid nitric acid pipeline, and the top of the liquid nitric acid pipeline is connected to the bottom of the white nitric acid self-blowing pipeline; the inlet of the cooling device is connected to the liquid nitric acid pipeline through a liquid discharge pipeline, the liquid outlet thereof is connected to a reactor, and the gas outlet thereof is connected to a tail gas absorption system; The secondary co-production unit is used to heat the white nitric acid and obtain the secondary product. The secondary co-production unit has the same structure as the primary co-production unit. Similarly, the top of the distillation tower unit of the secondary co-production unit is connected to the steam pipeline, and the top of the distillation tower unit is connected in series to N-stage co-production units through the steam pipeline, wherein N=3, 4, 5,...N, and the N-stage co-production unit has the same structure as the primary co-production unit. N-level co-production unit, used for heating and blowing white nitric acid to obtain N-level products, the top of the distillation tower unit of the N-level co-production unit is connected to the tail gas absorption system; A first packing layer is provided in the connecting pipeline, the first packing layer is located above the top of the heater, and the first packing layer is used to reflux the liquid nitric acid into the heater; The distillation tower unit comprises a distillation tower and a second packing layer located below the distillation tower, wherein the second packing layer is used to reflux liquid nitric acid into the self-blowing white pipe, and the second packing layer is filled with glass rings or Raschig rings; The cooling device comprises at least one condenser, the inlet end of the condenser is connected to the liquid discharge pipeline, the liquid outlet end of the condenser is connected to the reaction kettle, and the gas outlet of the condenser is connected to the tail gas absorption system.

2. The multi-level high-purity nitric acid co-production system according to claim 1, characterized in that: The raw material conveying system includes a raw material conveying pipeline, one end of which is connected to the raw material tank and the other end is connected to the heater. The cooling device is connected in series to the raw material conveying pipeline so that the material in the cooling device can exchange heat with the raw material in the raw material conveying pipeline.

3. The multi-level high-purity nitric acid co-production system according to claim 1, characterized in that: A heat exchanger is arranged in the self-blowing white pipe, and the heat exchanger is connected in series to the raw material conveying pipe so that the material in the self-blowing white pipe can exchange heat with the raw material in the raw material conveying pipe.

4. The multi-level high-purity nitric acid co-production system according to claim 1, characterized in that: The liquid discharge pipeline is provided with a discharge valve.

5. The multi-level high-purity nitric acid co-production system according to claim 1, characterized in that: The tail gas absorption system includes a first tail gas absorption pipeline and a second tail gas absorption pipeline, one end of the first tail gas absorption pipeline is connected to the gas outlet of the cooling device, and the other end thereof is connected to the tail gas absorption device, and one end of the second tail gas absorption pipeline is connected to the gas outlet of the reactor, and the other end thereof is connected to the tail gas absorption device.

6. A method for co-producing a multi-level high-purity nitric acid co-production system according to any one of claims 1 to 5, characterized in that: The following steps are involved: A. The nitric acid raw material is transported to the heater through the raw material transport system, heated by the heater to form steam and enter the primary co-production unit. The primary co-production unit heats and blows the condensed nitric acid through the self-blowing heater, collects the primary product, and enters the secondary co-production unit through the steam of the distillation tower unit; B. The secondary co-production unit heats and blows the condensed nitric acid through a self-blowing heater, and collects the secondary product. Similarly, the steam passing through the distillation tower unit enters the N-stage co-production unit in sequence, and obtains the tertiary product, the quaternary product,..., the N-stage product in sequence.

7. The co-production method according to claim 6, characterized in that: The output distribution of products at each level can be adjusted by adjusting the heating efficiency of the self-blowing white heaters of each level of co-production units.

Images