Device and method for removing nitrogen oxides and moisture in krypton-85 recovery process

Abstract

The invention provides a device and a method for removing nitrogen oxides and moisture in a krypton-85 recovery process, belongs to the technical field of gas purification, and is used for removing nitrogen oxides and moisture in gas before krypton-85 is recovered. The device comprises a mixer, a raw material preheater, a catalytic reduction tower, a cooler, a drying tower, a nitrogen oxide concentration analyzer and a dew-point meter. The mixer is used for mixing the ammonia gas and the dissolved tail according to a preset proportion to form mixed gas; and the raw material preheater preheats the mixed gas. And the catalytic reduction tower is used for carrying out ammonia catalytic reduction reaction so as to remove nitrogen oxides in the mixed gas. And the cooler is used for cooling the reacted gas so as to remove moisture in the gas. The drying tower further removes moisture in the gas. The nitrogen oxide concentration analyzer is used for detecting the nitrogen oxide concentration at the outlet of the cooler. The dew-point meter is used for detecting the outlet moisture concentration of the drying tower. The device can simply and efficiently remove nitrogen oxides and moisture in the dissolved tail gas.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas purification, and in particular relates to a device and method for removing nitrogen oxides and moisture in a krypton-85 recovery process. Background Art

[0002] During spent fuel dissolution and nuclear power plant operation, large quantities of krypton-85 (Kr-85) are generated. Direct release into the atmosphere can impact the environment and human health. Kr-85 also has a wide range of applications, including thickness gauges, nuclear lamps, and flaw detection. The lithium battery industry, in particular, sees a huge annual market demand for Kr-85 thickness gauges, making its recovery crucial. Extracting Kr-85 from the dissolved exhaust requires gas pretreatment, primarily involving nitrogen oxide and water removal. Nitrogen oxides, primarily nitrogen dioxide and nitric oxide, are produced during spent fuel dissolution and must be removed before Kr-85 recovery. Failure to do so can lead to competitive adsorption and explosions during the Kr-85 recovery process. Furthermore, nitrogen oxide emissions can pollute the environment. Failure to remove water vapor from the dissolved exhaust can lead to freezing and blockage during Kr-85 recovery using methods such as cryogenic adsorption and chromatography, disrupting the process. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to provide a device and method for removing nitrogen oxides and moisture in the krypton-85 recovery process, which can simply and efficiently remove nitrogen oxides and moisture in dissolved exhaust gas.

[0004] To address the above-mentioned issues, the present invention provides a device for removing nitrogen oxides and moisture in the krypton-85 recovery process, comprising: a mixer, a raw material preheater, a catalytic reduction tower, a cooler, a drying tower, a nitrogen oxide concentration analyzer, and a dew point meter. The mixer is connected to an ammonia source and a dissolved tail gas source, respectively. The mixer is used to mix ammonia and dissolved tail gas in a preset ratio to form a mixed gas. The raw material preheater is connected to the outlet of the mixer via a compressor. The raw material preheater is used to preheat the mixed gas. The catalytic reduction tower is connected to the outlet of the raw material preheater. The catalytic reduction tower is used to perform a catalytic reduction reaction with ammonia to remove nitrogen oxides from the mixed gas. The cooler is connected to the outlet of the catalytic reduction tower. The cooler is used to cool the post-reaction gas to remove moisture from the gas. The drying tower is connected to the outlet of the cooler. The drying tower is used to further remove moisture from the gas. The dry gas outlet of the drying tower is connected to the back-end process. The nitrogen oxide concentration analyzer is located at the outlet of the cooler. The nitrogen oxide concentration analyzer is used to detect the nitrogen oxide concentration at the outlet of the cooler. The dew point meter is located at the dry gas outlet of the drying tower. The dew point meter is used to detect the moisture concentration of the drying gas outlet of the drying tower.

[0005] Wherein, on the connecting pipe between the dissolved tail gas source and the mixer, a first manual valve, a first pressure gauge, a first flow meter and a nitrogen oxide concentration meter are sequentially provided along the gas flow direction.

[0006] A second regulating valve is provided between the compressor and the raw material preheater and is interlocked with the first flow meter.

[0007] Wherein, on the connecting pipe between the ammonia source and the mixer, a second manual valve, a first electric valve, a first back pressure valve, a second flow meter and a first regulating valve are sequentially provided along the gas flow direction.

[0008] Among them, the nitrogen oxide concentration analyzer is interlocked with the second flow meter and the first regulating valve.

[0009] The nitrogen oxide and moisture removal device during the krypton-85 recovery process also includes a first heater. The first heater is connected to the raw material preheater and the catalytic reduction tower. The catalytic reduction tower is equipped with a first temperature controller. The first temperature controller is interlocked with the first heater.

[0010] The cooler is provided with a liquid level controller, a second electric valve is provided at the cooling water discharge port of the cooler, and the liquid level controller is interlocked with the second electric valve.

[0011] The drying towers are configured as one for use and one for backup. Each drying tower is connected to a second heater. A second temperature controller is provided on the drying tower. The second temperature controller is interlocked with the second heater.

[0012] The drying tower also includes a regeneration gas pipeline. The regeneration gas pipeline inlet is connected to the drying gas outlet of the drying tower. The regeneration gas pipeline outlet is connected to the drying tower via a second heater. The regeneration gas pipeline is sequentially provided along the airflow direction with a fourth electric valve, a second backpressure valve, a third flowmeter, and a third regulating valve. The third regulating valve is interlocked with the third flowmeter.

[0013] The present invention also provides a method for removing nitrogen oxides and moisture in a krypton-85 recovery process, using the above-mentioned device for removing nitrogen oxides and moisture in a krypton-85 recovery process, the method comprises the following steps: S1. Preheating the catalytic reduction tower and precooling the cooler; S2. Start the compressor and allow air to enter the raw material preheater, catalytic reduction tower, cooler and drying tower in sequence until the pressure in the raw material preheater, catalytic reduction tower, cooler and drying tower reaches equilibrium; S3. Open the ammonia source and the dissolved tail gas source to carry out the ammonia catalytic reduction reaction of nitrogen oxides and the reaction gas drying process.

[0014] Beneficial effects: The device for removing nitrogen oxides and moisture in the krypton-85 recovery process provided by the present invention utilizes an ammonia catalytic reduction reaction to remove nitrogen oxides, and utilizes a cooler and a drying tower to gradually remove moisture from the gas. This device does not produce other harmful products and is highly efficient, simple in process, and easy to operate. It can purify krypton gas in a short period of time, which is beneficial to the recovery of krypton-85. It also reduces the waste of dissolved tail gas resources and lowers the risk of environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of a device for removing nitrogen oxides and moisture in a krypton-85 recovery process according to an embodiment of the present invention.

[0016] The reference numerals indicate: 1. Dissolved tail gas source; 2. First manual valve; 3. First pressure gauge; 4. First flow meter; 5. Nitrogen oxide concentration meter; 6. Ammonia source; 7. Second manual valve; 8. First electric valve; 9. First back pressure valve; 10. Second flow meter; 11. First regulating valve; 12. Mixer; 13. Compressor; 14. Bypass valve; 15. Second regulating valve; 16. Raw material preheater; 17. First thermometer; 18. First heater; 19. Second thermometer; 20. Catalytic reduction tower; 21. Third thermometer; 22. First temperature controller; 23. Cooler; 24. Fourth thermometer; 25. Second pressure gauge; 26. Water cooling unit; 27. Liquid level controller; 28. Second electric valve; 29. ​​Nitrogen oxide concentration analyzer; 30. Drying tower; 31. Fifth thermometer; 32. Second temperature controller; 33. Inlet valve; 34. Exhaust valve; 35. Outlet valve; 36. Second heater; 37. Sixth thermometer; 38. Third electric valve; 39. Third regulating valve; 40. Third flow meter; 41. Second back pressure valve; 42. Fourth electric valve; 43. Regeneration gas pipeline; 44. Dew point meter. DETAILED DESCRIPTION

[0017] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0018] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0019] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0020] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0021] This embodiment provides a device for removing nitrogen oxides and moisture in the krypton-85 recovery process. Figure 1 This is a schematic diagram of a device for removing nitrogen oxides and moisture in the krypton-85 recovery process provided in this embodiment.

[0022] like Figure 1 As shown, the apparatus for removing nitrogen oxides and moisture in the krypton-85 recovery process of this embodiment includes: a mixer 12, a raw material preheater 16, a catalytic reduction tower 20, a cooler 23, a drying tower 30, a nitrogen oxide concentration analyzer 29, and a dew point meter 44. The mixer 12 is connected to an ammonia source 6 and a dissolved tail gas source 1, respectively. The mixer 12 is used to mix ammonia and dissolved tail gas in a preset ratio to form a mixed gas. The raw material preheater 16 is connected to the outlet of the mixer 12 via a compressor 13. The raw material preheater 16 is used to preheat the mixed gas. The catalytic reduction tower 20 is connected to the outlet of the raw material preheater 16. The catalytic reduction tower 20 is used to perform a catalytic reduction reaction with ammonia to remove nitrogen oxides from the mixed gas. The cooler 23 is connected to the outlet of the catalytic reduction tower 20. The cooler 23 is used to cool the gas after the reaction to remove moisture from the gas. The drying tower 30 is connected to the outlet of the cooler 23. The drying tower 30 is used to further remove moisture from the gas. The drying gas outlet of the drying tower 30 is connected to the back-end process. A nitrogen oxide concentration analyzer 29 is installed at the outlet of the cooler 23. This analyzer is used to measure the nitrogen oxide concentration at the outlet of the cooler 23. A dew point meter 44 is installed at the drying gas outlet of the drying tower 30. This meter is used to measure the moisture concentration of the drying gas at the outlet of the drying tower 30.

[0023] In this embodiment, if Figure 1 As shown, the bypass valve 14 is also included. The bypass valve 14 is connected in parallel with the compressor 13. In this embodiment, the bypass valve 14 is provided in parallel with the compressor 13. When the compressor 13 is operating normally, the bypass valve 14 is closed, and the mixed gas flows through the compressor 13 into the raw material preheater 16. When the compressor 13 is not operating normally, the bypass valve 14 can be opened, allowing the mixed gas to enter the raw material preheater 16 through the bypass valve 14.

[0024] In this implementation, see Figure 1 The compressor 13 adopts a diaphragm compressor. The diaphragm compressor can completely isolate the mixed gas from the power part of the compressor 13, effectively preventing the mixed gas from leaking.

[0025] In this implementation, see Figure 1 The drying tower 30 adopts a molecular sieve drying tower. The molecular sieve drying tower has high adsorption efficiency and can quickly adsorb a large amount of water in a short time. In addition, the molecular sieve drying tower can realize the cycle operation of adsorption and regeneration during operation, saving energy.

[0026] In this implementation, if Figure 1 As shown, the pipes in this device are all made of stainless steel pipes. Stainless steel pipes have strong corrosion resistance, good air tightness, and good high and low temperature resistance.

[0027] In this embodiment, if Figure 1 As shown, the catalytic reduction tower 20 is used to perform selective ammonia catalytic reduction to remove nitrogen oxides in the mixed gas. The reaction process will release heat. The device uses the heat released by the catalytic reduction tower 20 to heat the raw material preheater 16, which is beneficial to saving energy and reducing the risk of environmental pollution.

[0028] In this embodiment, if Figure 1 As shown, the gas after the reaction in the catalytic reduction tower 20 enters the cooler 23 for cooling, and most of the water can be condensed and removed. The heat released by the cooler 23 can also be used to heat the raw material preheater 16 to further save energy.

[0029] The apparatus for removing nitrogen oxides and moisture in the krypton-85 recovery process of this embodiment utilizes an ammonia catalytic reduction reaction to remove nitrogen oxides, and utilizes a cooler 23 and a drying tower 30 to gradually remove moisture from the gas. This apparatus does not produce other harmful products and is highly efficient, simple in process, and easy to operate. It can purify krypton gas in a short period of time, which is beneficial for the recovery of krypton-85. It also reduces the waste of dissolved tail gas resources and lowers the risk of environmental pollution.

[0030] Among them, such as Figure 1As shown, in this embodiment, a first manual valve 2, a first pressure gauge 3, a first flow meter 4 and a nitrogen oxide concentration meter 5 are sequentially provided on the connecting pipe between the dissolved tail gas source 1 and the mixer 12 along the gas flow direction.

[0031] In this embodiment, a first manual valve 2 is provided at the outlet of the dissolved exhaust gas source 1, which can be manually controlled to open and close the dissolved exhaust gas source, making operation more convenient. A first pressure gauge 3, a first flowmeter 4, and a nitrogen oxide concentration meter 5 are provided on the connecting pipe between the dissolved exhaust gas source 1 and the mixer 12. These can obtain the discharge pressure, flow rate, and nitrogen oxide concentration of the dissolved exhaust gas in real time, which is beneficial for parameter setting and adjustment of subsequent processing steps.

[0032] Among them, such as Figure 1 As shown, in this embodiment, a second regulating valve 15 is provided between the compressor 13 and the raw material preheater 16. The second regulating valve 15 is interlocked with the first flow meter 4.

[0033] In this embodiment, the second regulating valve 15 is interlocked with the first flow meter 4 , and the opening of the second regulating valve 15 can be controlled according to the flow obtained by the first flow meter 4 , thereby controlling the air intake flow of the raw material preheater 16 .

[0034] Among them, such as Figure 1 As shown, in this embodiment, on the connecting pipe between the ammonia source 6 and the mixer 12, a second manual valve 7, a first electric valve 8, a first back pressure valve 9, a second flow meter 10 and a first regulating valve 11 are sequentially provided along the gas flow direction.

[0035] In this embodiment, a second manual valve 7 is provided at the outlet of the ammonia source 6. This allows for manual control of the opening and closing of the ammonia source 6 when the first electric valve 8 fails, making operation more convenient. A first back-pressure valve 9 is provided on the connecting pipe between the ammonia source 6 and the mixer 12 to prevent gas backflow and contamination of the ammonia source 6 by dissolved tail gas. A second flow meter 10 is provided to obtain real-time ammonia emission flow. A first regulating valve 11 is provided to control the opening of the first regulating valve 11 based on the flow rate obtained by the second flow meter 10, thereby controlling the flow rate of ammonia, which is beneficial for adjusting the mixing ratio of ammonia and dissolved tail gas.

[0036] Among them, such as Figure 1 As shown, in this embodiment, the nitrogen oxide concentration analyzer 29 is interlocked with the second flow meter 10 and the first regulating valve 11.

[0037] The nitrogen oxide concentration analyzer 29 of this embodiment is interlocked with the second flow meter 10 and the first regulating valve 11. The nitrogen oxide concentration analyzer 29 obtains the nitrogen oxide concentration after the reaction is completed, and controls the first regulating valve 11 according to the flow data of the second flow meter 10 and the nitrogen oxide concentration after the reaction is completed; if the nitrogen oxide concentration is high, the valve opening of the first regulating valve 11 is controlled to increase, and the flow rate increases accordingly to increase the ammonia ratio, and finally feedback is used to reduce the nitrogen oxide concentration after the reaction is completed.

[0038] Among them, such as Figure 1 As shown, in this embodiment, the apparatus for removing nitrogen oxides and moisture during the krypton-85 recovery process further includes a first heater 18. First heater 18 is connected to the feedstock preheater 16 and the catalytic reduction tower 20. Catalytic reduction tower 20 is provided with a first temperature controller 22. First temperature controller 22 is interlocked with first heater 18.

[0039] In this embodiment, if Figure 1 As shown, a first thermometer 17 is provided on the raw material preheater 16 to facilitate manual real-time acquisition of the temperature in the raw material preheater 16 .

[0040] In this embodiment, if Figure 1 As shown, a second thermometer 19 is provided on the first heater 18 to facilitate manual real-time acquisition of the heating temperature of the first heater 18 .

[0041] In this embodiment, if Figure 1 As shown, the catalytic reduction tower 20 is provided with a third thermometer 21 to facilitate manual real-time acquisition of the temperature in the catalytic reduction tower 20 .

[0042] In this embodiment, the first heater 18 is used to provide heat required for preheating and reaction of the raw material preheater 16 and the catalytic reduction tower 20. A first temperature controller 22 is interlocked with the first heater 18. The first temperature controller 22 detects the temperature in the catalytic reduction tower 20 and maintains the reaction temperature in the catalytic reduction tower 20 by controlling the heating efficiency of the first heater 18.

[0043] Among them, such as Figure 1 As shown, in this embodiment, a liquid level controller 27 is provided on the cooler 23. A second electric valve 28 is provided on the cooling water discharge port of the cooler 23. The liquid level controller 27 is interlocked with the second electric valve 28.

[0044] In this embodiment, if Figure 1 As shown, the cooler 23 is provided with a fourth thermometer 24 and a second pressure gauge 25 to facilitate obtaining the real-time temperature and pressure in the cooler 23 .

[0045] In this embodiment, if Figure 1As shown, the cooler 23 is connected to a water cooling unit 26 to circulate cooling water in the cooler 23 to improve the cooling efficiency of the cooler 23 on the reacted gas.

[0046] The liquid level controller 27 of this embodiment is used to monitor the condensed water level in the cooler 23. When the water level reaches a preset value, the liquid level controller 27 can open the second electric valve 28 to drain water.

[0047] Among them, such as Figure 1 As shown, in this embodiment, the drying tower 30 is used as one and is used as a backup. Each drying tower 30 is connected to a second heater 36. Each drying tower 30 is provided with a second temperature controller 32. The second temperature controller 32 is interlocked with the second heater 36.

[0048] In this implementation, if Figure 1 As shown, an air inlet valve 33 is provided on the air inlet of each drying tower 30; an air outlet of each drying tower 30 is connected to the back-end process, and an air outlet valve 35 is provided on the air outlet of the drying tower 30; an exhaust valve 34 is provided on the exhaust gas discharge port of each drying tower 30.

[0049] In this implementation, if Figure 1 As shown, each drying tower 30 is provided with a fifth thermometer 31, and each second heater 36 is provided with a sixth thermometer 37. This arrangement facilitates obtaining the real-time temperature of the drying tower 30 and the second heater 36.

[0050] In this embodiment, two drying towers 30 are provided, one in use and one in reserve, enabling alternating drying and regeneration of the gas, thereby improving drying efficiency and ensuring process continuity. A second temperature controller 32 monitors the temperature within the drying tower 30 and maintains a constant temperature within the drying tower 30 by controlling the start and stop times and heating power of the second heater 36.

[0051] Among them, such as Figure 1 As shown, in this embodiment, the drying tower 30 further includes a regeneration gas pipeline 43. The inlet of the regeneration gas pipeline 43 is connected to the drying gas outlet of the drying tower 30. The outlet of the regeneration gas pipeline 43 is connected to the drying tower 30 via the second heater 36. The regeneration gas pipeline 43 is provided with a fourth electric valve 42, a second backpressure valve 41, a third flowmeter 40, and a third regulating valve 39 in the order of gas flow. The third regulating valve 39 is interlocked with the third flowmeter 40.

[0052] In this implementation, if Figure 1 As shown, the outlet of the regeneration gas pipeline 43 is connected to the two second heaters 36 through two third electric valves 38. When the drying tower 30 is in operation, the regeneration process of the drying tower 30 can be shut down by closing the third electric valve 38.

[0053] The drying tower 30 of this embodiment utilizes its own exhausted dry gas for regeneration, which is energy-saving and environmentally friendly, avoids environmental pollution, and at the same time avoids increasing the gas processing capacity of the back-end process. In this embodiment, a fourth electric valve 42 is provided on the regeneration gas pipeline 43 to control the pipeline between the inlet of the regeneration gas pipeline 43 and the dry gas outlet of the drying tower 30; a second back pressure valve 41 is provided to prevent the backflow of the regeneration gas; a third flow meter 40 is provided to obtain the flow rate of the regeneration gas, and a third regulating valve 39 is provided to adjust the flow rate. Among them, the third regulating valve 39 is interlocked with the third flow meter 40, and the opening of the third regulating valve 39 can be adjusted according to the flow data obtained by the third flow meter 40, thereby controlling the flow rate of the regeneration gas entering the drying tower 30.

[0054] This embodiment further provides a method for removing nitrogen oxides and moisture during the krypton-85 recovery process. The method utilizes the apparatus for removing nitrogen oxides and moisture during the krypton-85 recovery process described in the above embodiment, and includes the following steps: S1 preheats the catalytic reduction tower 20 and precools the cooler 23; Specifically, preheating the catalytic reduction tower 20 includes turning on the first heater 18 at a temperature of 300-350°C until the bottom temperature of the catalytic reduction tower 20 exceeds 260°C and the top temperature reaches 140°C, completing preheating of the catalytic reduction tower 20. Precooling the cooler 23 includes starting the water cooling unit 26 until the temperature of the cooler 23 drops to a preset value, completing precooling of the cooler 23.

[0055] In other embodiments, step S1 further includes regenerating the drying tower 30. Specifically, the process includes turning on the second heater 36 connected to the drying tower 30, setting the heating temperature to 250°C, closing the air inlet valve 33 of the drying tower 30, opening the exhaust valve 34, and removing moisture for 8 hours. After the removal is complete, the air inlet valve 33 is opened, and the drying tower 30 is allowed to cool naturally.

[0056] S2 starts the compressor 13, so that the air sequentially enters the raw material preheater 16, the catalytic reduction tower 20, the cooler 23 and the drying tower 30, until the raw material preheater 16, the catalytic reduction tower 20, the cooler 23 and the drying tower 30 reaches a pressure equilibrium state; Specifically, after the compressor 13 is turned on, the system begins to take in air. After a period of time, when the pressure of the entire system is balanced, the nitrogen oxide concentration analyzer 29 and the dew point meter 44 can be turned on.

[0057] For example, the compressor 13 is turned on and the frequency of the compressor 13 is adjusted to 35 Hz. At this time, the air flow rate is about 15m 3 / h, the system starts to take in air; after a period of air intake and the pressure of the entire system is balanced, the nitrogen oxide concentration analyzer 29 and the dew point meter 44 are turned on.

[0058] S3. Open the ammonia source 6 and the dissolved tail gas source 1 to carry out the ammonia catalytic reduction reaction of nitrogen oxides and the reaction gas drying process.

[0059] Specifically, the ammonia source 6 and the dissolved tail gas source 1 are turned on, and the ammonia-nitrogen ratio is set to 0.85-1. The dissolved tail gas and ammonia enter the mixer 12, and the mixed gas passes through the compressor 13 and enters the raw material preheater 16 for preheating. The preheated gas is catalytically reduced with ammonia in the catalytic reduction tower 20 to remove NO. x The reaction product is primarily nitrogen, and no additional waste is generated. The post-reaction gas is cooled in cooler 23 to condense the water in the gas, removing most of the water. It then enters drying tower 30 for water vapor removal. The condensate level in cooler 23 must be monitored, as it can be obtained through level controller 27. When the condensate level reaches a preset value, either interlocked or manual discharge can be selected.

[0060] After the ammonia and nitrogen oxides react in the catalytic reduction tower 20, the outlet nitrogen oxide concentration is detected by the nitrogen oxide concentration analyzer 29 to be less than 50 ppm, and the outlet moisture concentration of the drying gas of the drying tower 30 is detected by the dew point meter 44 to be less than 30 ppm, which meets the requirements.

[0061] For example, the ammonia source 6 (such as a gas cylinder) is set to an ammonia gas (standard gas 20000ppm) flow rate of 43L / min and an intake pressure of 0.6MPa; the dissolved tail gas source 1 is set to a gas (standard gas 20000ppm) flow rate of 50L / min and an intake pressure of 0.6MPa. At this time, the ammonia-nitrogen ratio is 0.86.

[0062] Observe the reading of the nitrogen oxide concentration analyzer 29. After equilibrium, the nitrogen oxide content is about 13 ppm (of which the NO content is about 6 ppm and the NO2 content is about 7 ppm), which meets the requirement that the nitrogen oxide content is less than 50 ppm. Observe the reading of the dew point meter 44. After equilibrium, the moisture content is less than 30 ppm.

[0063] It should be noted that before step S1 is performed, all individual equipment is inspected, specifically including: the compressor 13 and the water-cooling unit 26 are in the shutdown state; ensuring that the catalytic reduction tower 20, the raw gas preheater 16, the cooler 23, the nitrogen oxide concentration analyzer 29, the dew point meter 44, and various pipelines and valves have been installed and connected, and all valves are in the closed state; ensuring that the first heater 18 is in the shutdown state, the lubricating oil level of the compressor 13 is normal, and the refrigerant liquid level of the water-cooling unit 26 is normal; and confirming that the catalyst in the catalytic reduction tower 20 has been loaded.

[0064] In addition, after the work is completed, it is necessary to turn off the ammonia source 6 and the dissolved tail gas source 1, and after purging for a period of time, turn off the compressor 13 to stop the system from receiving air, and close all electric valves, manual valves, water cooling units 26, and turn off the power of each electrical cabinet.

[0065] The method of this embodiment adopts the device for removing nitrogen oxides and moisture in the krypton-85 recovery process of the above embodiment, and therefore has all the above beneficial effects, which will not be described in detail here.

[0066] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0067] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art may make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection of the present invention.

Claims

1. A device for removing nitrogen oxides and moisture in a krypton-85 recovery process, characterized in that: include: Mixer, raw material preheater, catalytic reduction tower, cooler, drying tower, nitrogen oxide concentration analyzer and dew point meter; The mixer is connected to an ammonia source and a dissolved tail gas source respectively; the mixer is used to mix the ammonia and dissolved tail gas in a preset ratio to form a mixed gas; The raw material preheater is connected to the outlet of the mixer through a compressor; the raw material preheater is used to preheat the mixed gas; The catalytic reduction tower is connected to the outlet of the raw material preheater; the catalytic reduction tower is used to perform ammonia catalytic reduction reaction to remove nitrogen oxides in the mixed gas; The cooler is connected to the outlet of the catalytic reduction tower; the cooler is used to cool the gas after the reaction to remove moisture from the gas; The drying tower is connected to the outlet of the cooler; the drying tower is used to further remove moisture from the gas; the dry gas outlet of the drying tower is connected to the back-end process; The nitrogen oxide concentration analyzer is arranged at the outlet of the cooler; the nitrogen oxide concentration analyzer is used to detect the nitrogen oxide concentration at the outlet of the cooler; The dew point meter is arranged at the dry gas outlet of the drying tower; the dew point meter is used to detect the moisture concentration of the dry gas in the drying tower.

2. The device for removing nitrogen oxides and moisture in the krypton-85 recovery process according to claim 1, characterized in that: On the connecting pipe between the dissolved tail gas source and the mixer, a first manual valve, a first pressure gauge, a first flow meter and a nitrogen oxide concentration meter are sequentially provided along the gas flow direction.

3. The device for removing nitrogen oxides and moisture in the krypton-85 recovery process according to claim 2, characterized in that: A second regulating valve is provided between the compressor and the raw material preheater; the second regulating valve is interlocked with the first flow meter.

4. The device for removing nitrogen oxides and moisture in the krypton-85 recovery process according to claim 1, characterized in that: On the connecting pipe between the ammonia source and the mixer, a second manual valve, a first electric valve, a first back pressure valve, a second flow meter and a first regulating valve are sequentially provided along the gas flow direction.

5. The device for removing nitrogen oxides and moisture in the krypton-85 recovery process according to claim 4, characterized in that: The nitrogen oxide concentration analyzer is interlocked with the second flow meter and the first regulating valve.

6. The device for removing nitrogen oxides and moisture in the krypton-85 recovery process according to claim 1, characterized in that: It also includes a first heater; the first heater is connected to the raw material preheater and the catalytic reduction tower; the catalytic reduction tower is provided with a first temperature controller; The first temperature controller is interlocked with the first heater.

7. The device for removing nitrogen oxides and moisture in the krypton-85 recovery process according to claim 1, characterized in that: The cooler is provided with a liquid level controller; the cooling water discharge port of the cooler is provided with a second electric valve; The liquid level controller is interlocked with the second electric valve.

8. The device for removing nitrogen oxides and moisture in the krypton-85 recovery process according to claim 1, characterized in that: The drying towers are one for use and one for backup; each drying tower is connected to a second heater; a second temperature controller is provided on the drying tower; The second temperature controller is interlocked with the second heater.

9. The device for removing nitrogen oxides and moisture in the krypton-85 recovery process according to claim 8, characterized in that: The drying tower further includes a regeneration gas pipeline; the inlet of the regeneration gas pipeline is connected to the drying gas outlet of the drying tower; the outlet of the regeneration gas pipeline is connected to the drying tower through the second heater; On the regeneration gas pipeline, a fourth electric valve, a second back pressure valve, a third flow meter and a third regulating valve are sequentially provided along the air flow direction; The third regulating valve is interlocked with the third flowmeter.

10. A method for removing nitrogen oxides and moisture in a krypton-85 recovery process, using the device for removing nitrogen oxides and moisture in a krypton-85 recovery process according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: preheating the catalytic reduction tower and precooling the cooler; Starting the compressor to allow air to enter the raw material preheater, the catalytic reduction tower, the cooler, and the drying tower in sequence until pressure equilibrium is reached in the raw material preheater, the catalytic reduction tower, the cooler, and the drying tower; The ammonia source and the dissolved tail gas source are opened to carry out an ammonia catalytic reduction reaction of nitrogen oxides and a reaction gas drying process.

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