Nitric acid tail gas recovery device

Abstract

The utility model provides a nitric acid tail gas recovery device and belongs to the technical field of chemical engineering. The utility model provides a nitric acid tail gas recovery device which comprises a nitric acid tail gas emptying pipeline, a gas-liquid separator and a low-pressure reaction water cooler, nitric acid tail gas is introduced into the nitric acid tail gas emptying pipeline, and a liquid ring compressor is arranged on the nitric acid tail gas emptying pipeline; the nitric acid tail gas emptying pipeline is connected with the gas-liquid separator, the gas-liquid separator is used for carrying out gas-liquid separation, the gas-liquid separator is provided with a gas discharge pipeline, a liquid discharge pipeline and a liquid discharge pipeline, and the gas-liquid separator is used for separating obtained NOX gas; and the gas exhaust pipeline is connected with the low-pressure reaction water cooler. According to the nitric acid tail gas recovery device, nitric acid tail gas is collected and enters the gas-liquid separator through the liquid ring compressor, gas-liquid separation is carried out on NOX gas carrying liquid, the NOX gas enters the low-pressure reaction water cooler to be pressurized and cooled, the obtained NOX gas is sent back to a nitric acid device, and recycling of the NOX gas is achieved.

Description

Technical Field

[0001] This utility model belongs to the field of chemical technology, specifically relating to a nitric acid tail gas recovery device. Background Technology

[0002] Nitric acid is a strong acid with strong oxidizing and corrosive properties, and is an important chemical raw material. Nitric acid plants produce a large amount of nitric acid tail gas during the nitric acid production process. Nitric acid tail gas is a common industrial waste gas, containing a large amount of NO. X Gas (commonly referred to as nitrogen oxides NO) X The main pollutants include NO, NO2, N2O, N2O3, N2O4, and N2O5. NO is easily generated at low altitudes in the tailrace tank and nitric acid storage tank of the nitric acid plant. X The large-scale spillage of gas and the emission of nitric acid tail gas have caused serious environmental pollution and posed a serious threat to the on-site environment and occupational health of personnel. In particular, the spillage will be exacerbated during the low-pressure and high-temperature season in summer.

[0003] There are various methods for purifying nitrogen oxides both domestically and internationally. One method is liquid absorption for treating nitric acid tail gas. Liquid absorption typically uses water or aqueous solutions of acids, alkalis, or salts as absorbents to absorb nitrogen oxides from the waste gas, thus purifying it. During the treatment process, a jet pump can be used to discharge the nitric acid tail gas into a nitric acid wastewater tank. However, the absorption effect is limited, and the treated nitric acid tail gas still contains NO. X The gas also causes serious exceedances of nitrate ions in the nitric acid wastewater pond. The discharge of treated nitric acid tail gas and wastewater still causes some pollution to the environment and also wastes resources. Utility Model Content

[0004] The purpose of this invention is to provide a nitric acid tail gas recovery device, which aims to solve the problem that nitric acid tail gas still causes environmental pollution after treatment.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is: to provide a nitric acid tail gas recovery device, comprising:

[0006] A nitric acid tail gas venting pipe, wherein nitric acid tail gas is introduced into the nitric acid tail gas venting pipe, and a liquid ring compressor is installed on the nitric acid tail gas venting pipe;

[0007] A gas-liquid separator is connected to the nitric acid tail gas exhaust pipe. The gas-liquid separator processes the NO entrained liquid discharged from the liquid ring compressor. X Gas-liquid separation is performed on the gas. The gas-liquid separator is equipped with a gas discharge pipe, a liquid inlet pipe, and a liquid outlet pipe. The NO separated by the gas-liquid separator... X The gas is discharged through the gas discharge pipe; and

[0008] A low-pressure reaction water cooler is connected to the gas discharge pipe, and the low-pressure reaction water cooler is used to treat NO. X The gas is pressurized, cooled, and then recovered.

[0009] In one possible implementation, the liquid discharge pipe is connected to the tailwater tank, and a tailwater pump is installed on the liquid discharge pipe.

[0010] In one possible implementation, the liquid discharge pipe is connected to the tailwater tank of the tower, and a liquid level control valve is installed on the liquid discharge pipe.

[0011] In one possible implementation, the gas-liquid separator is further provided with a liquid supply pipe, which is connected to the liquid inlet of the liquid ring compressor.

[0012] In one possible implementation, a heat exchanger is provided on the liquid supply pipeline.

[0013] In one possible implementation, a gas return pipe is provided on the gas discharge pipe, the first end of the gas return pipe is provided on the nitric acid tail gas vent pipe, and a pressure control valve is provided on the gas return pipe.

[0014] In one possible implementation, the liquid ring compressor is disposed between the first end of the gas return pipe and the gas-liquid separator.

[0015] In one possible implementation, the low-pressure reaction water cooler is connected to the dilute nitrate absorption tower of the nitric acid plant via a pipeline.

[0016] In one possible implementation, a dilute nitrate NO₃⁻ filter is installed between the low-pressure reaction water cooler and the dilute nitrate absorption tower. X Separator, NO X Compressor, exhaust gas preheater, and high-pressure reaction water cooler.

[0017] In one possible implementation, the gas-liquid separator is also provided with an acid replenishment pipe.

[0018] The beneficial effects of the nitric acid tail gas recovery device provided by this utility model are as follows:

[0019] Compared with existing technologies, this system is equipped with a nitric acid tail gas venting pipeline, a gas-liquid separator, and a low-pressure reaction water cooler. The nitric acid tail gas venting pipeline is used for transporting nitric acid tail gas. It can be connected to all devices in the nitric acid plant that generate nitric acid tail gas. By collecting and transporting the nitric acid tail gas through the pipeline, the leakage of nitric acid tail gas is reduced, thereby lowering the NO concentration in the air surrounding the nitric acid plant. XThe liquid ring compressor is installed on the nitric acid tail gas exhaust pipe. Water or other liquids are introduced into the liquid ring compressor. When the liquid ring compressor is running, under the action of centrifugal force, the water or other liquid forms a liquid ring inside the liquid ring compressor, which in turn removes NO from the nitric acid tail gas exhaust pipe. X The gas is discharged into the gas-liquid separator, NO X The gas contains liquid, and the NO containing the liquid... X The gas undergoes gas-liquid separation in a gas-liquid separator, and the separated NO... X The gas exits the gas-liquid separator through a gas discharge pipe and enters the low-pressure reaction water cooler. The low-pressure reaction water cooler is a component of the nitric acid plant, used to hold the NO produced during the nitric acid production process. X Process gas, NO obtained from separation X Gases and NO X Process gas mixing, low-pressure reaction water cooler for NO... X The gas is pressurized and cooled to achieve NO removal. X The recovery of gases reduces pollution to the external environment and reduces the waste of resources. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the structure of the nitric acid tail gas recovery device provided in the embodiment of this utility model.

[0022] In the diagram: 1. Nitric acid tail gas venting pipe; 2. Liquid ring compressor; 3. Gas-liquid separator; 4. Gas discharge pipe; 5. Liquid inlet pipe; 6. Liquid outlet pipe; 7. Low-pressure reaction water cooler; 8. Tower tail water tank; 9. Tower tail water pump; 10. Acid replenishment pipe; 11. Liquid level control valve; 12. Liquid supply pipe; 13. Heat exchanger; 14. Heat exchange water supply pipe; 15. Heat exchange water outlet pipe; 16. Gas reflux pipe; 17. Pressure control valve; 18. Dilute nitrate absorption tower; 19. Dilute nitrate NO X Separator; 20. Pump liquid inlet pipe; 21. Pump liquid outlet pipe; 22. Vent pipe; 23. Control valve; 24. NO X 25. Compressor; 26. Exhaust gas preheater; 27. High-pressure reaction water cooler. Detailed Implementation

[0023] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0024] Please refer to Figure 1 This invention provides a specific embodiment of a nitric acid tail gas recovery device, comprising a nitric acid tail gas exhaust pipe 1, a gas-liquid separator 3, and a low-pressure reaction water cooler 7. Nitric acid tail gas is introduced into the nitric acid tail gas exhaust pipe 1, and a liquid ring compressor 2 is installed on the nitric acid tail gas exhaust pipe 1. The nitric acid tail gas exhaust pipe 1 is connected to the gas-liquid separator 3, which processes the NO entrained in liquid discharged from the liquid ring compressor 2. X The gas undergoes gas-liquid separation. The gas-liquid separator 3 is equipped with a gas discharge pipe 4, a liquid inlet pipe 5, and a liquid outlet pipe 6. The NO separated by the gas-liquid separator 3... X The gas is discharged through gas discharge pipe 4; gas discharge pipe 4 is connected to low-pressure reaction water cooler 7, which is used to treat NO. X The gas is pressurized, cooled, and then recovered.

[0025] This utility model provides a nitric acid tail gas recovery device, which, compared with the prior art, includes a nitric acid tail gas exhaust pipe 1, a gas-liquid separator 3, and a low-pressure reaction water cooler 7. The nitric acid tail gas exhaust pipe 1 is used for transporting nitric acid tail gas and can be connected to all devices in the nitric acid plant that generate nitric acid tail gas. By collecting and transporting the nitric acid tail gas through the nitric acid tail gas exhaust pipe 1, the leakage of nitric acid tail gas is reduced, and the NO concentration in the air around the nitric acid plant is lowered. X The liquid ring compressor 2 is installed on the nitric acid tail gas exhaust pipe 1. Water or other liquids are introduced into the liquid ring compressor 2. When the liquid ring compressor 2 is running, under the action of centrifugal force, the water or other liquids form a liquid ring inside the liquid ring compressor 2, which in turn removes NO from the nitric acid tail gas exhaust pipe 1. X The gas is discharged into the gas-liquid separator 3, NO X The gas contains liquid, and the NO containing the liquid... X The gas undergoes gas-liquid separation in gas-liquid separator 3, and the separated NO... X The gas exits through gas discharge pipe 4 from gas-liquid separator 3 and enters low-pressure reaction water cooler 7. Low-pressure reaction water cooler 7 is a component of the nitric acid plant and is used to store NO produced during the nitric acid production process. X Process gas, NO obtained from separation X Gases and NO X Process gas mixing, low-pressure reaction water cooler 7 for its internal NOX The gas is pressurized and cooled to achieve NO removal. X The recovery of gases reduces pollution to the external environment and reduces the waste of resources.

[0026] For details, please refer to Figure 1 Nitric acid tail gas enters from the first end of nitric acid tail gas exhaust pipe 1, is compressed by liquid ring compressor 2, and then enters gas-liquid separator 3 from the second end of nitric acid tail gas exhaust pipe 1. The second end of nitric acid tail gas exhaust pipe 1 is located in the middle of the side wall of gas-liquid separator 3. The first end of gas exhaust pipe 4 is located at the top of gas-liquid separator 3, suitable for NO X The first end of the liquid inlet pipe 5 is located in the middle of the side wall of the gas-liquid separator 3, facilitating liquid entry into the gas-liquid separator 3 for gas-liquid separation. The first end of the liquid outlet pipe 6 is located at the lower end of the gas-liquid separator 3, facilitating the discharge of liquid from the gas-liquid separator 3. The low-pressure reaction water cooler 7 is connected to the second end of the gas outlet pipe 4. The low-pressure reaction water cooler 7 is used for NO... X The gas is pressurized and cooled to remove NO. X Gases and NO X The process gases are mixed and then enter the next stage of the nitric acid unit to remove NO from the nitric acid tail gas. X Gas recovery and reuse.

[0027] As a specific embodiment of the nitric acid tail gas recovery device provided by this utility model, please refer to Figure 1 The liquid discharge pipe 5 is connected to the tail water tank 8, and the tail water pump 9 is installed on the liquid discharge pipe 5.

[0028] For details, please refer to Figure 1 The second end of the liquid discharge pipe 5 is connected to the tail water tank 8. The tail water tank 8 is used to provide tail water to the liquid discharge pipe 5, reducing the waste of water resources. The tail water pump 9 is installed on the liquid discharge pipe 5 to facilitate the control of the amount of tail water entering the gas-liquid separator 3.

[0029] As a specific embodiment of the nitric acid tail gas recovery device provided by this utility model, please refer to Figure 1 The liquid discharge pipe 6 is connected to the tail water tank 8 of the tower, and a liquid level control valve 11 is installed on the liquid discharge pipe 6.

[0030] For details, please refer to Figure 1The second end of the liquid discharge pipe 6 is connected to the tail water tank 8. The tail water tank 8 is used to collect the tail water discharged from the gas-liquid separator 3, so as to realize the recycling of the tail water and reduce the waste of water resources. The liquid level control valve 11 is installed on the liquid discharge pipe 6 to facilitate the control of the amount of tail water discharged from the gas-liquid separator 3. The tail water pump 9 and the liquid level control valve 11 work together to control and adjust the liquid level in the gas-liquid separator 3, which helps the gas-liquid separator 3 to operate normally.

[0031] As a specific embodiment of the nitric acid tail gas recovery device provided by this utility model, please refer to Figure 1 The gas-liquid separator 3 is also equipped with a liquid supply pipe 12, which is connected to the liquid inlet of the liquid ring compressor 2.

[0032] For details, please refer to Figure 1 The first end of the liquid supply pipe 12 is set on the gas-liquid separator 3, on the side wall of the gas-liquid separator 3. The second end of the liquid supply pipe 12 is connected to the liquid inlet of the liquid ring compressor 2. Part of the tail water in the gas-liquid separator 3 can enter the liquid ring compressor 2 through the liquid supply pipe 12 to provide the liquid required for the operation of the liquid ring compressor 2, which helps the liquid ring compressor 2 to operate normally and helps to reduce the waste of water resources. The liquid ring compressor 2 is set close to the gas-liquid separator 3. The liquid ring compressor 2 is replenished with liquid through the gas-liquid separator 3, which can shorten the length of the liquid supply pipe 12.

[0033] Furthermore, the upper end of the gas-liquid separator 3 is also provided with a vent pipe 22, and a control valve 23 is provided on the vent pipe 22 to facilitate the discharge of the treated exhaust gas.

[0034] As a specific embodiment of the nitric acid tail gas recovery device provided by this utility model, please refer to Figure 1 A heat exchanger 13 is installed on the liquid supply pipeline 12.

[0035] For details, please refer to Figure 1 The heat exchanger 13 is installed on the liquid supply pipe 12. The heat exchanger 13 is connected to the heat exchange water supply pipe 14 and the heat exchange water outlet pipe 15, which facilitates the flow of cooling water in the heat exchanger 13, reduces the temperature of the liquid entering the liquid ring compressor 2, and helps the liquid ring compressor 2 to operate normally.

[0036] For further details, please refer to Figure 1A pump liquid inlet pipe 20 is provided on the heat exchange water supply pipe 14. The other end of the pump liquid inlet pipe 20 is connected to the liquid inlet of the liquid ring compressor 2. The heat exchange water supply pipe 14 can replenish the liquid required for the operation of the liquid ring compressor 2 and can also perform heat exchange and cooling inside the liquid ring compressor 2. A pump liquid outlet pipe 21 is provided on the heat exchange water outlet pipe 15. The other end of the pump liquid outlet pipe 21 is connected to the liquid outlet of the liquid ring compressor 2. During the operation of the liquid ring compressor 2, the liquid inside it can be discharged through the pump liquid outlet pipe 21.

[0037] As a specific embodiment of the nitric acid tail gas recovery device provided by this utility model, please refer to Figure 1 A gas return pipe 16 is provided on the gas discharge pipe 4. The first end of the gas return pipe 16 is provided on the nitric acid tail gas discharge pipe 1. A pressure control valve 17 is provided on the gas return pipe 16.

[0038] For details, please refer to Figure 1 The first end of the gas return pipe 16 is connected to the nitric acid tail gas vent pipe 1, and the second end of the gas return pipe 16 is connected to the gas discharge pipe 4. The gas return pipe 16 connects the nitric acid tail gas vent pipe and the gas discharge pipe 4. The NO discharged in the gas discharge pipe 4... X Gas can flow back into the nitric acid tail gas vent pipe through gas return pipe 16. Pressure control valve 17 is installed on gas return pipe 16, and pressure control valve 17 regulates the flow of NO back into the nitric acid tail gas vent pipe. X The amount of gas helps to regulate the pressure balance of the device.

[0039] As a specific embodiment of the nitric acid tail gas recovery device provided by this utility model, please refer to Figure 1 The liquid ring compressor 2 is located between the first end of the gas return pipe 16 and the gas-liquid separator 3.

[0040] For details, please refer to Figure 1 The liquid ring compressor 2 is located near the gas-liquid separator 3, and the NO recirculated in the gas return pipe 16 X The gas enters the nitric acid tail gas exhaust pipe 1, passes through the liquid ring compressor 2, and then re-enters the gas-liquid separator 3, reducing NO. X The release of gases reduces environmental pollution.

[0041] As a specific embodiment of the nitric acid tail gas recovery device provided by this utility model, please refer to Figure 1 The low-pressure reaction water cooler 7 is connected to the dilute nitrate absorption tower 18 of the nitric acid unit via a pipeline.

[0042] For details, please refer to Figure 1 The nitric acid plant includes a dilute nitric acid absorption tower 18 for nitric acid production, and a low-pressure reaction water cooler 7 containing NO.X The gas is discharged into dilute nitrate absorption tower 18 for the production of nitric acid and to achieve NO reduction. X Gas recovery and reuse.

[0043] As a specific embodiment of the nitric acid tail gas recovery device provided by this utility model, please refer to Figure 1 A dilute nitrate NO3-O2 filter is installed between the low-pressure reaction water cooler 7 and the dilute nitrate absorption tower 18. X Separator 19, NO X Compressor 24, exhaust gas preheater 25, and high-pressure reaction water cooler 26.

[0044] For details, please refer to Figure 1 , dilute NO X Separator 19, NO X Compressor 24, exhaust gas preheater 25, and high-pressure reaction water cooler 26 are sequentially arranged between low-pressure reaction water cooler 7 and dilute nitrate absorption tower 18. X Separator 19 is used for further gas-liquid separation, NO X Compressor 24 is used to enhance NO X The gas pressure, exhaust gas preheater 25, and high-pressure reaction water cooler 26 can control NO. X The gas is cooled, providing high-pressure, low-temperature NO. X Gases that contribute to NO X The gas undergoes an absorption reaction inside the dilute nitrate absorption tower 18.

[0045] As a specific embodiment of the nitric acid tail gas recovery device provided by this utility model, please refer to Figure 1 The gas-liquid separator 3 is also equipped with an acid replenishment pipe 10.

[0046] For details, please refer to Figure 1 The acid supply pipe 10 is installed on the side wall of the gas-liquid separator 3 to facilitate the supply of acid to the gas-liquid separator 3 and accelerate gas-liquid separation.

[0047] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A nitric acid tail gas recovery device, characterized in that, include: A nitric acid tail gas venting pipe, wherein nitric acid tail gas is introduced into the nitric acid tail gas venting pipe, and a liquid ring compressor is installed on the nitric acid tail gas venting pipe; A gas-liquid separator is connected to the nitric acid tail gas exhaust pipe. The gas-liquid separator processes the NO entrained liquid discharged from the liquid ring compressor. X Gas-liquid separation is performed on the gas. The gas-liquid separator is equipped with a gas discharge pipe, a liquid inlet pipe, and a liquid outlet pipe. The NO separated by the gas-liquid separator... X The gas is discharged through the gas discharge pipe; as well as A low-pressure reaction water cooler is connected to the gas discharge pipe, and the low-pressure reaction water cooler is used to treat NO. X The gas is pressurized, cooled, and then recovered.

2. The nitric acid tail gas recovery device as described in claim 1, characterized in that, The liquid discharge pipe is connected to the tail water tank of the tower, and a tail water pump is installed on the liquid discharge pipe.

3. The nitric acid tail gas recovery device as described in claim 1, characterized in that, The liquid discharge pipe is connected to the tail water tank of the tower, and a liquid level control valve is installed on the liquid discharge pipe.

4. The nitric acid tail gas recovery device as described in claim 1, characterized in that, The gas-liquid separator is also equipped with a liquid supply pipe, which is connected to the liquid inlet of the liquid ring compressor.

5. The nitric acid tail gas recovery device as described in claim 4, characterized in that, A heat exchanger is installed on the liquid supply pipeline.

6. The nitric acid tail gas recovery device as described in claim 1, characterized in that, A gas return pipe is provided on the gas discharge pipe, and the first end of the gas return pipe is located on the nitric acid tail gas discharge pipe. A pressure control valve is provided on the gas return pipe.

7. The nitric acid tail gas recovery device as described in claim 6, characterized in that, The liquid ring compressor is located between the first end of the gas return pipe and the gas-liquid separator.

8. The nitric acid tail gas recovery device as described in claim 1, characterized in that, The low-pressure reaction water cooler is connected to the dilute nitrate absorption tower of the nitric acid plant via a pipeline.

9. The nitric acid tail gas recovery device as described in claim 8, characterized in that, A dilute nitrate NO solution is installed between the low-pressure reaction water cooler and the dilute nitrate absorption tower. X Separator, NO X Compressor, exhaust gas preheater, and high-pressure reaction water cooler.

10. The nitric acid tail gas recovery device as described in claim 1, characterized in that, The gas-liquid separator is also equipped with an acid replenishment pipeline.

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