Air pollutant purification system and purification method

Abstract

The invention provides an air pollutant purification system and method, and relates to the field of air pollutant purification, the air pollutant purification system comprises a freezing assembly, an air circulation assembly, a desorption assembly and a discharge assembly, various gaseous pollutants can be treated through a liquid nitrogen freezing technology which is difficult to achieve through a single technology, the gaseous pollutants are frozen or liquefied through low temperature, and the gaseous pollutants can be treated through a desorption assembly. Various pollutants can be efficiently removed in a short time. Besides, the air pollutant purification system comprises three working conditions of purification, desorption and emission, and the three working conditions are tightly matched to form a closed-loop system, so that efficient purification of various air pollutants is realized. The arrangement of a closed-loop system ensures thorough removal of pollutants and efficient operation of the system, and has extremely high energy utilization efficiency and environmental protection property.

Description

Technical Field

[0001] The present invention relates to the field of air pollutant purification, and in particular to an air pollutant purification system and a purification method. Background Art

[0002] In indoor working and living areas, due to the widespread presence of paints, coatings, adhesives, rubber, mechanical operating equipment, etc., as well as the natural emission of gases through human breathing, there are a large number of gaseous pollutants in the air in indoor working and living areas, such as carbon dioxide, benzene series, hydrocarbons, formaldehyde, sulfur dioxide, hydrogen sulfide, etc. The presence of these air pollutants affects human health and requires air pollutant purification. For general occasions, ventilation can be used to purify air pollutants. However, when the concentration of external atmospheric pollutants is high, or when the heat load or moisture load is too high, or when underground spaces are restricted by other conditions and are inconvenient to ventilate with the external atmosphere, in order to purify the air, the industry often uses a combination of multiple air pollutant purification technologies, such as adsorption by porous materials of different pore sizes, alkaline solution absorption, metal oxide catalysis, photocatalysis, etc.

[0003] The above solutions have the problem that a single technology can only treat a limited number of pollutants. If the goal of purifying multiple air pollutants at the same time is to be achieved, a combination of multiple technical solutions is needed. Summary of the Invention

[0004] In view of this, the present invention proposes an air pollutant purification system and purification method to solve the problem that a single technology can only treat a limited number of pollutants.

[0005] The technical solution of the present invention is achieved as follows:

[0006] In one aspect, the present invention provides an air pollutant purification system, comprising:

[0007] A freezing assembly, comprising a liquid nitrogen container and a freezing chamber, wherein a heat exchange coil is provided in the freezing chamber, wherein the liquid nitrogen container is connected to the inlet end of the heat exchange coil, and the outlet end of the heat exchange coil is connected to an exhaust assembly for discharging used nitrogen to the outside of the system through the exhaust assembly;

[0008] An air circulation assembly includes a blower, a return air duct network, a supply air duct network, and a regenerator. The return air duct network is connected to the air inlet of the freezing chamber through the regenerator, and is used to pass the air to be purified through the regenerator and then enter the freezing chamber for freezing or liquefaction of gaseous pollutants. The air outlet of the freezing chamber is connected to the supply air duct network through the regenerator. The blower is connected in series to the supply air duct network, and the supply air duct network is used to return the purified air to the control area.

[0009] Desorption components, used to remove solid pollutants from the low-temperature surfaces of the regenerator and freezing chamber;

[0010] The exhaust component is used to discharge the desorbed gaseous pollutants to the outside of the system.

[0011] On the basis of the above technical solution, preferably, the regenerator is provided with an air intake channel and a first heat exchange channel, the return air duct network includes a return air duct, a return air port and a second electric stop valve, the inlet end of the return air duct is located in the return air area and is connected to a plurality of return air ports, the outlet end of the return air duct is connected to the inlet of the air intake channel, the outlet of the air intake channel is connected to the air inlet of the freezing chamber, and the second electric stop valve is provided on the return air duct;

[0012] The air supply network includes an air supply pipeline, a first electric stop valve, a flow meter and an air supply outlet. The inlet end of the air supply pipeline is connected to the outlet of the first heat exchange channel, the inlet of the first heat exchange channel is connected to the air outlet of the freezing chamber, the outlet end of the air supply pipeline is arranged in the air supply area and is connected to multiple air supply outlets. The blower, the first electric stop valve and the flow meter are arranged sequentially on the air supply pipeline along the air flow direction of the air supply pipeline.

[0013] On the basis of the above technical solution, preferably, the exhaust component includes an exhaust pipeline, an exhaust heater, a third electric stop valve and a fourth electric stop valve, one end of the air pipeline is connected to the outlet end of the heat exchange coil, and the other end is used to connect to the external environment of the system, and the exhaust heater, the third electric stop valve and the fourth electric stop valve are all arranged on the exhaust pipeline in sequence along the air flow direction of the exhaust pipeline.

[0014] On the basis of the above technical solution, preferably, a pre-cooling pipeline is further included, and the pre-cooling pipeline includes a first pipeline, a second pipeline and a fifth electric stop valve. A second heat exchange channel is also provided in the regenerator, one end of the first pipeline is connected to the outlet end of the heat exchange coil, and the other end is connected to the inlet of the second heat exchange channel. The fifth electric stop valve is arranged on the first pipeline, one end of the second pipeline is connected to the outlet of the second heat exchange channel, and the other end is connected to the exhaust pipeline between the third electric stop valve and the fourth electric stop valve.

[0015] On the basis of the above technical solution, preferably, the desorption assembly includes a desorption heater, a desorption cross-tube and a sixth electric stop valve, the two ends of the desorption cross-tube are respectively connected to the return air pipeline and the supply air pipeline, and the desorption heater and the sixth electric stop valve are both provided on the desorption cross-tube;

[0016] The discharge assembly includes a purge pipeline, a nitrogen container, a seventh electric stop valve, a third pipeline, and an eighth electric stop valve. The nitrogen container is connected to the air supply pipeline between the blower and the regenerator through the purge pipeline. The seventh electric stop valve is arranged on the purge pipeline. One end of the third pipeline is connected to the freezing chamber, and the other end is connected to the exhaust pipeline between the third electric stop valve and the fourth electric stop valve. The eighth electric stop valve is arranged on the third pipeline.

[0017] Based on the above technical solution, preferably, the liquid nitrogen container is connected to the inlet of the heat exchange coil through a vacuum insulation pipeline, and an electric regulating valve is further provided on the vacuum insulation pipeline. A first temperature sensor is provided at the inlet end of the return air pipeline, a second temperature sensor is provided at the air inlet of the freezing chamber, a third temperature sensor is provided at the air outlet of the freezing chamber, a fourth temperature sensor is provided in the freezing chamber, a fifth temperature sensor is provided at the outlet of the heat exchange coil, and a sixth temperature sensor is provided at the inlet end of the supply air pipeline; an inlet air pressure sensor and at least one inlet air pollutant concentration sensor are provided at one end of the return air pipeline close to the regenerator, a return air pressure sensor and at least one return air pollutant concentration sensor are provided at one end of the supply air pipeline close to the regenerator, and a nitrogen concentration sensor is further provided on the third pipeline.

[0018] In a second aspect, the present invention further discloses a method for purifying air pollutants, which utilizes the air pollutant purification system described in the first aspect and includes the following steps:

[0019] S1, cooling stage: the low-temperature nitrogen in the liquid nitrogen container is passed into the heat exchange coil of the freezing chamber to provide a low-temperature cooling source for the entire purification system;

[0020] S2, pre-cooling stage: After the blower is started, the air to be purified in the environment is sucked into the return air duct network and enters the system, then transported to the regenerator and then into the freezing chamber, where it exchanges heat with the heat exchange coil and cools down. The low-temperature air leaves the freezing chamber and enters the regenerator, which can cool the regenerator body and the incoming air. At the same time, the return air temperature rises, leaves the regenerator, enters the supply air duct network, and is transported to the air outlet and returns to the environment. When the air temperature in the freezing chamber, the temperature of the regenerator body, the return air temperature, and the incoming air temperature are all reduced to the rated operating point, the air purification stage begins;

[0021] S3, air purification stage: the incoming air enters the freezing chamber, exchanges heat with the heat exchange coil and cools down. The gaseous pollutants in the air are liquefied and frozen on the surface of the heat exchange coil and in the freezing chamber, and the air is purified.

[0022] S4. When the air purification stage reaches a certain time, the heater and the freezing chamber are heated by the desorption component to desorb the pollutants;

[0023] S5. After the desorption of pollutants is completed, the desorbed air pollutants in the system are replaced by the exhaust component, and steps S1 to S4 are performed again.

[0024] On the basis of the above technical solution, preferably, when the inlet air temperature of the freezing chamber is greater than 112K, the fourth electric stop valve is opened, and a portion of the low-temperature pre-cooling nitrogen is diverted to the first pipeline through the fourth electric stop valve and enters the regenerator to accelerate the cooling process of the regenerator; when the inlet air temperature of the freezing chamber is less than or equal to 112K, with respect to the fourth electric stop valve, the supply of low-temperature nitrogen to the regenerator by the pre-cooling pipeline is stopped.

[0025] On the basis of the above technical scheme, preferably, when the detection value of the incoming air pollutant concentration sensor is less than the set target value, the operating frequency of the blower is 10% of the rated air volume of the blower; when the detection value of the incoming air pollutant concentration sensor is less than 20% of the set target value, the operating frequency of the blower increases exponentially; when the detection value of the incoming air pollutant concentration sensor is greater than 20% of the set target value, the operating frequency of the blower increases linearly; when the detection value of the fifth temperature sensor is less than or equal to 97K, the opening of the electric control valve is 10% of the rated opening; when the detection value of the fifth temperature sensor is greater than 97K, the opening of the electric control valve increases linearly or exponentially.

[0026] On the basis of the above technical solution, preferably, when the monitored pressure difference between the incoming and return air increases to twice the initial value, or the CO2 concentration difference between the incoming air and the return air decreases to within 30%, it is determined that pollutant desorption is required; when the detection values ​​of the second temperature sensor, the third temperature sensor, the fourth temperature sensor and the sixth temperature sensor are all greater than the ambient temperature value, it is determined that the pollutant desorption is completed, the air blower and the desorption heater are turned off, and when the nitrogen concentration detected by the nitrogen concentration sensor is greater than 99%, it is determined that the pollutant emission is completed.

[0027] The present invention has the following beneficial effects compared to the prior art:

[0028] (1) The air pollutant purification system disclosed in the present invention can treat a variety of gaseous pollutants (such as CO2, benzene series, hydrocarbons, formaldehyde, etc.) through liquid nitrogen freezing technology, which is difficult to achieve with a single technology. By freezing or liquefying the gaseous pollutants at low temperatures, it can achieve efficient removal of a variety of pollutants in a short period of time. In addition, the air pollutant purification system includes three working conditions: purification, desorption and emission. The three working conditions work closely together to form a closed-loop system, which achieves efficient purification of a variety of air pollutants. The setting of the closed-loop system ensures the thorough removal of pollutants and the efficient operation of the system, and has extremely high energy utilization efficiency and environmental protection. This closed-loop system is particularly suitable for places where external pollution is relatively serious or ventilation conditions are limited, and provides a comprehensive and effective solution for improving indoor air quality.

[0029] (2) The dual-channel design of the regenerator (the air inlet channel and the first heat exchange channel) can fully utilize the heat exchange process of the gas to achieve pre-cooling of the unpurified air and heat energy recovery of the purified air, which greatly improves the energy-saving effect of the system and reduces the refrigeration burden of the freezing chamber.

[0030] (3) By installing an exhaust heater on the exhaust pipe, the low-temperature nitrogen discharged from the heat exchange coil can be heated in time to increase the temperature of the nitrogen discharge, thereby avoiding condensation and icing at the discharge port due to temperature difference during the discharge process.

[0031] (4) By pre-cooling the return gas, the air entering the freezer has already been cooled. This reduces the refrigeration load required by the freezer components, helps improve the freezing efficiency of air pollutants, and further enhances the purification effect of the system. The pre-cooled airflow exchanges heat with the low-temperature nitrogen when passing through the regenerator, which can lower the air temperature before entering the freezer, helping to more effectively freeze or liquefy gaseous pollutants, improve purification efficiency, and reduce the refrigeration load of the freezer components.

[0032] (5) The desorption and emission components provide an effective solution to the problem of pollutant solidification in low-temperature environments. The desorption component heats the air inside the closed piping system and uses the circulating heated air to convert the solidified pollutants into gaseous form, thus avoiding the freezing and accumulation of pollutants in the freezing chamber and regenerator, which affects the purification efficiency. The emission component ensures that the gaseous pollutants after desorption can be safely discharged from the system to prevent secondary pollution. The overall design improves the long-term stability and energy efficiency of the system, reduces maintenance costs, and provides higher operational reliability and efficiency for the air pollutant purification system.

[0033] (6) By adding temperature, pressure, and concentration sensors and vacuum insulation piping, the system's ability to monitor and adjust parameters such as temperature, pressure, and pollutant concentration in real time has been enhanced. The installation of these sensors enables the system to more accurately control operations during the cooling, desorption, and discharge processes, avoiding unnecessary waste of cooling resources and improving the safety of pollutant emissions and the stability of system operation.

[0034] (7) By adjusting the operating frequency of the blower based on the pollutant concentration, the system can save energy when the air pollution is low and respond quickly when the pollutant concentration increases to ensure the purification effect. By precisely controlling the liquid nitrogen flow rate through the fifth temperature sensor, the system can avoid energy waste while ensuring the cooling effect, achieving a dynamic balance between energy saving and efficiency. The flexible adjustment of the blower frequency and the opening of the electric control valve enables the system to quickly respond to environmental changes and maintain the stability of the air purification and cooling process. This multi-variable coordinated control not only improves the automation level of the system, but also enhances the operating stability under different loads. (8) Through the comprehensive monitoring of the air flow pressure difference, CO2 concentration difference and multi-point temperature sensor data, intelligent control of the pollutant desorption process is achieved. When the system detects the conditions requiring desorption, the desorption process is automatically started; after the desorption is completed and the pollutants are discharged, the system automatically shuts down the relevant equipment to save energy. Through this multi-parameter and multi-condition joint control, the system can efficiently and safely complete the desorption and discharge of pollutants, improving the stability and reliability of the overall operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 This is a schematic diagram of the overall structure of the air pollutant purification system disclosed in the present invention;

[0037] Figure 2 This is a schematic diagram of the air pollutant purification process disclosed in the present invention;

[0038] Figure 3 This is a schematic diagram of the air pollutant desorption process disclosed in the present invention;

[0039] Figure 4 This is a schematic diagram of the air pollutant emission process disclosed in the present invention;

[0040] Reference numerals:

[0041] 1. Refrigeration assembly; 11. Liquid nitrogen container; 111. Vacuum insulation piping; 112. Electric regulating valve; 12. Freezing chamber; 13. Heat exchange coil; 14. Exhaust assembly; 141. Exhaust piping; 142. Discharge heater; 143. Third electric stop valve; 144. Fourth electric stop valve;

[0042] 2. Air circulation assembly; 21. Air blower; 22. Return air duct network; 221. Return air duct; 222. Return air outlet; 223. Second electric shut-off valve; 224. Return air outlet;

[0043] 23. Air supply network; 231. Air supply pipeline; 232. First electric shut-off valve; 233. Flow meter; 234. Air supply port; 24. Regenerator; 241. Air inlet channel; 242. First heat exchange channel; 243. Second heat exchange channel;

[0044] 3. Desorption assembly; 31. Desorption heater; 32. Desorption cross-pipe; 33. Sixth electric stop valve; 4. Discharge assembly; 41. Purge line; 42. Nitrogen container; 43. Seventh electric stop valve; 44. Third line; 45. Eighth electric stop valve; 5. Precooling line; 51. First line; 52. Second line; 53. Fifth electric stop valve;

[0045] T1, first temperature sensor; T2, second temperature sensor; T3, third temperature sensor; T4, fourth temperature sensor; T5, fifth temperature sensor; T6, sixth temperature sensor; P1, incoming air pressure sensor; P2, return air pressure sensor; X1, incoming air pollutant concentration sensor; X2 pollutant concentration sensor; X3, nitrogen concentration sensor. DETAILED DESCRIPTION

[0046] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0047] like Figure 1 As shown, combined Figure 2-4 An embodiment of the present invention discloses an air pollutant purification system, including a refrigeration component 1, an air circulation component 2, a desorption component 3 and an exhaust component 4.

[0048] Among them, the freezing component 1 includes a liquid nitrogen container 11 and a freezing chamber 12. A heat exchange coil 13 is provided in the freezing chamber 12. The liquid nitrogen container 11 is connected to the inlet end of the heat exchange coil 13, and the outlet end of the heat exchange coil 13 is connected to the exhaust component 14, which is used to discharge the used nitrogen to the outside of the system through the exhaust component 14.

[0049] The liquid nitrogen container 11 provides a low-temperature cooling source for the entire purification system. The temperature of the liquid nitrogen in the liquid nitrogen container 11 is 77K (-196°C). The liquid nitrogen container 11 is in a gas-liquid two-phase coexistence state, with liquid nitrogen at the bottom and nitrogen gas at the top. After absorbing heat, the liquid nitrogen continuously evaporates into nitrogen gas, providing a continuous supply of low-temperature nitrogen gas to the outside. The low-temperature nitrogen gas produced by the liquid nitrogen tank is transported to the freezing chamber 12, which can maintain the low temperature state of the freezing chamber 12 to achieve low-temperature liquefaction or freezing of air pollutants.

[0050] The medium in the heat exchange coil 13 is low-temperature nitrogen provided by the liquid nitrogen container 11, which can reduce the temperature of the space outside the heat exchange coil 13 (i.e., the main space of the freezing chamber 12) to nearly -196°C. The pollutants in the air entering the freezing chamber 12 are frozen or liquefied at this temperature.

[0051] The exhaust assembly 14 is used to discharge the used nitrogen to the outside of the system after completing the heat exchange in the freezing chamber 12.

[0052] The air circulation component 2 includes a blower 21, a return air duct network 22, an air supply duct network 23 and a regenerator 24. The return air duct network 22 is connected to the air inlet of the freezing chamber 12 through the regenerator 24, and is used to pass the air to be purified through the regenerator 24 into the freezing chamber 12 for freezing or liquefying gaseous pollutants. The air outlet of the freezing chamber 12 is connected to the air supply duct network 23 through the regenerator 24. The blower 21 is connected in series to the air supply duct network 23, and the air supply duct network 23 is used to return the purified air to the control area.

[0053] In this embodiment, the return air duct network 22 draws polluted air from the room and delivers it to the system for purification. The regenerator 24 reduces energy loss during the air circulation process. Specifically, the regenerator 24 precools the return air and preheats the supply air, improving energy efficiency. The blower 21 ensures airflow, ensuring that the purified air can be promptly returned to the control area. The supply air duct network 23 returns the purified air to the work or living area, forming a closed-loop air circulation system. This closed-loop air circulation system prevents the secondary entry of polluted air from outside the system, ensuring a stable purification effect. The regenerator 24 improves energy efficiency, making the system more energy-efficient.

[0054] The desorption component is used to remove solid pollutants from the low-temperature surfaces of the regenerator 24 and the freezing chamber 12. In a low-temperature environment, the pollutants will solidify on the heat exchange surface and need to be desorbed as time accumulates. The setting of the desorption component 3 ensures that these pollutants can be removed regularly to avoid excessive accumulation of pollutants in the system, which affects the heat exchange efficiency.

[0055] The exhaust component 4 is used to discharge the desorbed gaseous pollutants outside the system. The desorbed gaseous pollutants must be discharged safely to prevent them from circulating within the system. This component prevents the pollutants from re-entering the room, preventing secondary accumulation of pollutants within the system and ensuring stable system operation. The exhausted gas can be further processed, such as through an adsorption tower or catalytic reaction, to reduce environmental pollution.

[0056] The air pollutant purification system disclosed in the present invention can process a variety of gaseous pollutants (such as CO2, benzene series, hydrocarbons, formaldehyde, etc.) through liquid nitrogen freezing technology, which is difficult to achieve with a single technology. By freezing or liquefying the gaseous pollutants at low temperatures, it can achieve efficient removal of a variety of pollutants in a short period of time. In addition, the air pollutant purification system includes three working conditions: purification, desorption and emission. The sequential connection of the three working conditions forms a complete closed-loop system, which achieves efficient purification of a variety of air pollutants. The setting of the closed-loop system ensures the thorough removal of pollutants and the efficient operation of the system, and has extremely high energy utilization efficiency and environmental protection. This closed-loop system is particularly suitable for places where external pollution is relatively serious or ventilation conditions are limited, and provides a comprehensive and effective solution for improving indoor air quality.

[0057] In this embodiment, an air intake channel 241 and a first heat exchange channel 242 are provided in the regenerator 24, wherein the two ends of the air intake channel 241 are respectively connected to the inlet of the return air duct 221 and the air intake of the freezing chamber 12, so that the air entering from the return air duct 221 enters the freezing chamber 12 through the air intake channel 241, and the first heat exchange channel 242 is connected to the air outlet of the freezing chamber 12 and the inlet of the air supply duct 231, so as to exchange heat with the discharged cooling air and enter the air supply duct network 23 after heat exchange.

[0058] The direct connection between the air intake channel 241 and the freezing chamber 12 ensures that the return air undergoes heat exchange before entering the freezing chamber 12, pre-cooling the return air gas and reducing the consumption of liquid nitrogen. The function of the first heat exchange channel 242 is to recover the cold energy of the low-temperature air discharged from the freezing chamber 12 to pre-cool the return air in the air intake channel 241, thereby reducing the energy demand of the freezing process and achieving significant energy-saving effects on the overall system.

[0059] The dual-channel design of the regenerator 24 (the air inlet channel 241 and the first heat exchange channel 242) can make full use of the heat exchange process of the gas to achieve pre-cooling of the unpurified air and heat energy recovery of the purified air, greatly improving the energy-saving effect of the system and reducing the refrigeration burden of the freezing chamber 12.

[0060] The return air duct network 22 includes a return air duct 221, return air inlets 224, and a second electric shut-off valve 223. The inlet of the return air duct 221 is located in the return air area and is connected to multiple return air inlets 224, drawing air from various locations within the room. The outlet of the return air duct 221 is connected to the inlet of an air intake channel 241, which in turn is connected to the air intake of the freezing chamber 12. The second electric shut-off valve 223 is located on the return air duct 221.

[0061] In this embodiment, return air duct 221 is used to collect air to be purified from the environment. Multiple return air ports 224 ensure that air is drawn in from different areas, avoiding uneven local air purification. Second electric stop valve 223 is used to control whether air from the environment is drawn into return air duct 221. When operating in air purification mode, second electric stop valve 223 needs to be open. When operating in desorption and discharge modes, second electric stop valve 223 needs to be closed.

[0062] The air supply network 23 includes an air supply pipeline 231, a first electric shut-off valve 232, a flowmeter 233, and air outlets 234. The inlet of the air supply pipeline 231 is connected to the outlet of the first heat exchange channel 242, which in turn is connected to the air outlet of the freezing chamber 12. The outlet of the air supply pipeline 231 is located in the air supply area and is connected to multiple air outlets 234. The design of multiple air outlets 234 ensures that the purified air is evenly distributed throughout the interior space. The blower 21, the first electric shut-off valve 232, and the flowmeter 233 are sequentially arranged on the air supply pipeline 231 along the air flow direction of the air supply pipeline 231. The first electric shut-off valve 232 is used to control the air flow in the air supply pipeline 231, and the flowmeter 233 is used to monitor the air supply volume in real time.

[0063] In this embodiment, when the entire system is in the purification working condition, the first electric stop valve 232 needs to be opened, and when in the desorption working condition and the emission working condition, the first electric stop valve 232 needs to be closed.

[0064] Based on the above technical solution, when low-temperature nitrogen is passed into the heat exchange coil 13 and heat-exchanges and freezes or liquefies the air pollutants introduced into the freezer compartment, the temperature of the low-temperature nitrogen will rise. At this time, this part of the nitrogen needs to be discharged in time to ensure that the liquid nitrogen container 11 can continue to pass low-temperature nitrogen into the heat exchange coil 13. Since the temperature of the low-temperature nitrogen is relatively low, the temperature will still be relatively low after heat exchange. If it is discharged directly at this time, it may cause ice or condensation at the discharge port, affecting the discharge of the low-temperature nitrogen and affecting the safety of the system.

[0065] To this end, this embodiment shows a preferred structural mode of the exhaust component 14. Specifically, the exhaust component 14 includes an exhaust pipeline 141, an exhaust heater 142, a third electric stop valve 143 and a fourth electric stop valve 144. One end of the air pipeline is connected to the outlet end of the heat exchange coil 13, and the other end is used to connect to the external environment of the system. The exhaust heater 142, the third electric stop valve 143 and the fourth electric stop valve 143 are all arranged in sequence on the exhaust pipeline 141 along the air flow direction of the exhaust pipeline 141.

[0066] In this embodiment, the discharge heater 142 can timely heat the low-temperature nitrogen discharged from the heat exchange coil 13 to increase the temperature of the nitrogen discharge, thereby avoiding condensation and ice formation at the discharge port due to temperature difference during the discharge process.

[0067] The third electric stop valve 143 and the fourth electric stop valve 144 are set. In this embodiment, the third electric stop valve 143 mainly controls the on-off of the exhaust pipe 141, and the fourth electric stop valve 144 serves as the general exhaust on-off. Under the purification mode, the third electric stop valve 143 is closed and the fourth electric stop valve 144 is open. Under the desorption mode and the emission mode, the third electric stop valve 143 is closed and the fourth electric stop valve 144 is opened. In this way, when in the desorption mode and the emission mode, the third electric stop valve 143 is closed, and the low-temperature nitrogen in the heat exchange coil 13 cannot be discharged through the emission component 4. However, when in the emission mode, the gaseous pollutants desorbed in the freezing chamber 12 can be introduced into the exhaust pipe 141, and when the fourth electric stop valve 144 is open, the desorbed gaseous pollutants are discharged to the outside of the system. This part of the gaseous pollutants will not return to the system and can be processed by other gas processing equipment to avoid polluting the environment.

[0068] As some preferred embodiments, a pre-cooling pipeline 5 is further included, and the pre-cooling pipeline 5 includes a first pipeline 51, a second pipeline 52 and a fifth electric stop valve 53.

[0069] In addition to the original air inlet channel 241 and first heat exchange channel 242, the regenerator 24 also has a second heat exchange channel 243 for exchanging heat with the low-temperature nitrogen in the pre-cooling pipeline 5. This design enables the regenerator 24 to simultaneously process two airflows of different temperatures, achieving more efficient energy exchange.

[0070] One end of the first pipeline 51 is connected to the outlet end of the heat exchange coil 13 , and the other end is connected to the inlet end of the second heat exchange channel 243 , and is responsible for introducing the low-temperature nitrogen discharged from the heat exchange coil 13 into the regenerator 24 .

[0071] The fifth electric stop valve 53 is provided on the first pipeline 51 and is used to control the timing and flow rate of the low-temperature nitrogen gas flowing into the regenerator 24 to ensure the controllability of the low-temperature nitrogen gas recovery process.

[0072] One end of the second pipeline 52 is connected to the outlet of the second heat exchange channel 243, and the other end is connected to the exhaust pipeline 141 between the third electric stop valve 143 and the fourth electric stop valve 144. The second pipeline 52 is used to guide the low-temperature nitrogen passing through the regenerator 24 to the exhaust pipeline 141 for discharge.

[0073] By pre-cooling the return gas, the air entering the freezer compartment is already cooled. This reduces the refrigeration load required by the freezer assembly 1, helping to improve the freezing efficiency of air pollutants and further enhance the system's purification effectiveness. The pre-cooled airflow exchanges heat with the low-temperature nitrogen as it passes through the regenerator 24, bringing the air temperature to a lower level before entering the freezer compartment. This helps to more effectively freeze or liquefy gaseous pollutants, improving purification efficiency and reducing the refrigeration load of the freezer assembly 1.

[0074] During the freezing process, the system consumes a large amount of energy to generate low-temperature nitrogen. The coldness of this part of the low-temperature nitrogen is recovered through the pre-cooling pipeline 5, avoiding the energy waste caused by direct discharge. By using the low-temperature nitrogen discharged from the freezing to pre-cool the reflowing air to be purified, the cooling energy consumption required in the regenerator 24 can be reduced, thereby improving the overall energy utilization efficiency of the system.

[0075] Because the low-temperature nitrogen undergoes heat exchange in the regenerator 24, the exhaust gas is preheated by the return air in the regenerator 24 before being discharged. This not only increases the exhaust temperature and reduces the impact on the external environment, but also prevents condensation or ice formation during the discharge process.

[0076] This embodiment shows a preferred structural mode of the desorption component 3. Specifically, the desorption component 3 includes a desorption heater 31, a desorption cross-pipe 32 and a sixth electric stop valve 33. The two ends of the desorption cross-pipe 32 are respectively connected to the return air duct 221 and the supply air duct 231. The desorption heater 31 and the sixth electric stop valve 33 are both arranged on the desorption cross-pipe 32.

[0077] In this embodiment, the desorption cross-over duct 32 connects the return air duct 221 and the supply air duct 231. Thus, the desorption cross-over duct 32, the return air duct 221, the freezing chamber 12, the supply air duct 231, and the blower 21 form a closed piping system. Opening the sixth electric shut-off valve 33 opens this closed piping system, establishing an internal circulation system.

[0078] It is worth noting that when desorption is required, the first electric stop valve 232 and the second electric stop valve 223 need to be closed. In this way, the closed pipeline system will not be connected to the indoor environment, and the air to be purified will not be introduced.

[0079] The desorption heater 31 heats the air within the closed duct system, while the blower 21 circulates the heated air within the duct system. This heated air heats the solidified pollutants within the freezing chamber 12 and regenerator 24, converting them into a gaseous state and enabling desorption. This process effectively prevents the long-term accumulation of pollutants, ensuring that they are regularly removed and preventing them from affecting system performance.

[0080] After the solidified pollutants in the freezing chamber 12 and the regenerator 24 are desorbed, it is necessary to discharge the gaseous pollutants in time so as to implement a new round of purification. In order to discharge the gaseous pollutants, this embodiment shows a preferred structural mode of the discharge component 4.

[0081] Specifically, the discharge assembly 4 includes a purge pipeline 41, a nitrogen container 42, a seventh electric stop valve 43, a third pipeline 44, and an eighth electric stop valve 45. The nitrogen container 42 is connected to the air supply pipeline 231 between the blower 21 and the regenerator 24 through the purge pipeline 41. The seventh electric stop valve 43 is arranged on the purge pipeline 41. One end of the third pipeline 44 is connected to the freezing chamber 12, and the other end is connected to the exhaust pipeline 141 between the third electric stop valve 143 and the fourth electric stop valve 144. The eighth electric stop valve 45 is arranged on the third pipeline 44.

[0082] Using the above technical solution, under this working condition, the blower 21 is in the closed state. At this time, the seventh electric stop valve 43 and the eighth electric stop valve 45 are both open, and nitrogen is continuously introduced into the air supply pipeline 231 through the nitrogen container 42. After the nitrogen is mixed with the gaseous pollutants in the closed pipeline system, it is discharged into the external environment through the exhaust pipeline 141 through the third pipeline 44. Other gas purification equipment can be connected here to further treat the gaseous pollutants.

[0083] The configuration of desorption assembly 3 and emission assembly 4 provides an effective solution to the problem of pollutant solidification in low-temperature environments. Desorption assembly 3 heats the air within the closed piping system, converting the solidified pollutants into a gaseous state using the circulating heated air. This prevents pollutants from freezing and accumulating in freezing chamber 12 and regenerator 24, which could affect purification efficiency. Emission assembly 4 ensures that desorbed gaseous pollutants can be safely discharged from the system, preventing secondary contamination. This overall design improves the system's long-term stability and energy efficiency, reduces maintenance costs, and provides higher operational reliability and efficiency for the air pollutant purification system.

[0084] In this embodiment, liquid nitrogen container 11 is connected to the inlet of heat exchange coil 13 via vacuum insulated piping 111, which is also equipped with an electric regulating valve 112. Low-temperature nitrogen gas generated by the liquid nitrogen tank is transported to freezing chamber 12 via vacuum insulated piping 111 (the pipe wall has a vacuum insulation layer to reduce cold loss of the low-temperature nitrogen gas). This maintains the low temperature of freezing chamber 12, thereby achieving cryogenic liquefaction or freezing of air pollutants. Electric regulating valve 112 is used to adjust the flow of low-temperature nitrogen gas from liquid nitrogen container 11 into freezing chamber 12.

[0085] A first temperature sensor T1 is provided at the inlet of the return air duct 221, responsible for monitoring the temperature of the air flowing into the regenerator 24. A second temperature sensor T2 is provided at the air inlet of the freezing chamber 12, for monitoring the air inlet temperature of the freezing chamber 12, and a third temperature sensor T3 is provided at the air outlet of the freezing chamber 12, for monitoring the air outlet temperature of the freezing chamber 12. A fourth temperature sensor T4 is provided in the freezing chamber 12, for monitoring the air temperature inside the freezing chamber 12. A fifth temperature sensor T5 is provided at the outlet of the heat exchange coil 13, for monitoring the temperature of the low-temperature nitrogen leaving the freezing chamber 12. A sixth temperature sensor T6 is provided at the inlet of the supply air duct 231, for monitoring the return air temperature of the regenerator 24.

[0086] An inlet air pressure sensor P1 and at least one inlet air pollutant concentration sensor X1 are installed at the end of the return air duct 221 near the regenerator 24. A return air pressure sensor P2 and at least one return air pollutant concentration sensor X2 are installed at the end of the supply air duct 231 near the regenerator 24. The inlet air pressure sensor P1 is used to monitor the inlet air pressure of the regenerator 24, while the return air pressure sensor P2 is used to monitor the return air pressure of the regenerator 24. The inlet air pollutant concentration sensor X1 is used to monitor the concentration of specific gaseous pollutants in the inlet air of the regenerator 24 (before purification), while the return air pollutant concentration sensor X2 is used to monitor the concentration of specific gaseous pollutants in the return air of the regenerator 24 (after purification).

[0087] A nitrogen concentration sensor is also provided on the third pipeline 44 for monitoring the concentration of discharged nitrogen under emission conditions.

[0088] The addition of temperature, pressure, and concentration sensors, along with vacuum-insulated piping 111, enhances the system's ability to monitor and adjust parameters like temperature, pressure, and pollutant concentration in real time. These sensors enable more precise control of the system during cooling, desorption, and discharge, avoiding unnecessary waste of cooling resources and improving pollutant emission safety and system operational stability.

[0089] The present invention discloses a method for purifying air pollutants, comprising the following steps:

[0090] S1, cooling stage: the low-temperature nitrogen in the liquid nitrogen container 11 is passed into the heat exchange coil 13 of the freezing chamber 12 to provide a low-temperature cooling source for the entire purification system;

[0091] S2, pre-cooling stage: After the blower 21 is started, the air to be purified in the environment is sucked into the return air duct network 22 and enters the system, and is transported to the regenerator 24, and then enters the freezing chamber 12, where it exchanges heat with the heat exchange coil 13 for cooling. The low-temperature air leaves the freezing chamber 12 and enters the regenerator 24, which can cool the regenerator 24 body and the incoming air. At the same time, the return air itself is heated up, leaves the regenerator 24, enters the air supply duct network 23, and is transported to the air supply port 234 and returns to the environment. When the air temperature in the freezing chamber 12, the temperature of the regenerator body, the return air temperature, and the incoming air temperature are all reduced to the rated operating point, the air purification stage begins;

[0092] S3, air purification stage: the incoming air enters the freezing chamber 12, exchanges heat with the heat exchange coil 13 and cools down. The gaseous pollutants in the air are liquefied and frozen on the surface of the heat exchange coil 13 and in the freezing chamber 12, and the air is purified;

[0093] S4, when the air purification stage reaches a certain time, the heater and the freezing chamber 12 are heated by the desorption component 3 to desorb the pollutants;

[0094] S5. After the desorption of pollutants is completed, the desorbed air pollutants in the system are replaced by the exhaust component 4, and steps S1 to S4 are performed again.

[0095] In some specific embodiments, when the air inlet temperature of the freezing chamber 12 is greater than 112K, the fourth electric stop valve 144 is opened, and a portion of the low-temperature pre-cooling nitrogen is diverted to the first pipeline 51 through the fourth electric stop valve 144 and enters the regenerator 24 to accelerate the cooling process of the regenerator 24; when the air inlet temperature of the freezing chamber 12 is less than or equal to 112K, with respect to the fourth electric stop valve 144, the supply of low-temperature nitrogen from the pre-cooling pipeline 5 to the regenerator 24 is stopped.

[0096] When the air inlet temperature of the freezing chamber 12 exceeds 112K, it means that the temperature of the air entering the freezing chamber 12 is relatively high. At this time, the system opens the fourth electric stop valve 144, allowing part of the low-temperature nitrogen to enter the first pipeline 51 through the fourth electric stop valve 144 and flow to the regenerator 24. After the low-temperature pre-cooled nitrogen enters the regenerator 24, the return air temperature can be quickly reduced by heat exchange. By pre-cooling the return gas, the air entering the freezing chamber has been pre-cooled. This reduces the refrigeration load required by the freezing component 1, helps to improve the freezing efficiency of air pollutants, and further improves the purification effect of the system. The pre-cooled airflow exchanges heat with the low-temperature nitrogen when passing through the regenerator 24, which can make the air reach a lower temperature before entering the freezing chamber, which helps to more effectively freeze or liquefy gaseous pollutants, improve purification efficiency, and reduce the refrigeration load of the freezing component 1.

[0097] When the inlet air temperature of freezing chamber 12 drops to 112K or lower, the system has reached a relatively ideal cooling state. No additional pre-cooling nitrogen is required to cool regenerator 24. The system then closes fourth electric shut-off valve 144, halting the supply of low-temperature nitrogen to regenerator 24. This automated control mechanism not only improves system efficiency but also avoids unnecessary energy consumption, enhancing the system's overall energy efficiency.

[0098] In this embodiment, the configuration of the fourth electric shut-off valve 144 provides the system with automated temperature regulation capabilities, allowing the flow rate of pre-cooled nitrogen to be flexibly adjusted based on the actual inlet temperature of the freezing chamber 12. This not only helps maintain system temperature stability but also effectively improves the operating efficiency of the purification system.

[0099] When the detection value of the incoming air pollutant concentration sensor X1 is less than the set target value, the operating frequency of the blower 21 is 10% of the rated air volume of the blower 21. This means that when the air pollutant concentration is low, the system only needs to operate at a very low air volume. Because there are fewer pollutants, the load on the purification system is lighter, which helps to save energy consumption.

[0100] When the incoming air pollutant concentration sensor X1 detects a value less than 20% of the set target, the operating frequency of blower 21 increases exponentially. At this point, the system recognizes that the pollutant concentration is in a low range and increases the frequency of blower 21 exponentially to gradually increase the air flow rate to meet the needs of treating mild pollution. This exponential growth mode allows the system to maintain low energy consumption in the initial stage while rapidly increasing air supply capacity as pollutant concentration increases.

[0101] When the incoming air pollutant concentration sensor X1 detects a value greater than 20% of the set target value, the operating frequency of blower 21 increases linearly. This indicates that the air pollutant concentration exceeds a certain range of the preset target value, indicating an increase in the air purification load. The system needs to linearly increase the frequency of blower 21 to ensure a larger air flow to handle the higher pollutant concentration. This linear increase regulation method is more controllable and suitable for maintaining system stability under higher loads.

[0102] When the detection value of the fifth temperature sensor T5 is less than or equal to 97K, the opening of the electric control valve 112 is 10% of the rated opening. The fifth temperature sensor T5 is responsible for monitoring the temperature at the outlet of the heat exchange coil 13. When the temperature drops to 97K or lower, the system determines that the cooling effect has reached the expected level. Therefore, the opening of the electric control valve 112 is set to 10%, which helps to reduce the flow rate of liquid nitrogen, thereby avoiding overcooling and saving energy.

[0103] When the detection value of the fifth temperature sensor T5 exceeds 97K, the opening of the electric control valve 112 increases linearly or exponentially. Specifically, when the temperature exceeds 97K, the system determines that the cooling effect is insufficient and needs to increase the flow of liquid nitrogen to further reduce the temperature. The opening of the control valve will increase linearly or exponentially depending on the demand, and the choice of increase method depends on the actual temperature rise of the system. If rapid cooling is required, exponential growth may be used; if the temperature rise is only small, linear growth may be used to achieve smooth control.

[0104] By adjusting the operating frequency of the blower 21 based on the pollutant concentration, the system can save energy when the air pollution is low, and respond quickly when the pollutant concentration increases to ensure the purification effect. And through the precise control of the liquid nitrogen flow by the fifth temperature sensor T5, the system can avoid energy waste while ensuring the cooling effect, achieving a dynamic balance between energy saving and efficiency. The flexible adjustment of the frequency of the blower 21 and the opening of the electric control valve 112 enables the system to respond quickly to environmental changes and maintain the stability of the air purification and cooling process. This multi-variable collaborative control not only improves the automation level of the system, but also enhances the operational stability under different loads.

[0105] The blower 21 and electric control valve 112 are regulated by dual monitoring of air pollutant concentration and temperature, employing flexible linear or exponential regulation strategies to maximize system energy efficiency. When air pollutant concentration is low or cooling is ideal, the system automatically reduces energy consumption. When load increases or temperature rises, the system can quickly adjust to ensure air purification and cooling efficiency. This control strategy ensures both efficient system operation and rational energy utilization.

[0106] The control logic for starting the desorption condition is: when the monitored pressure difference between the incoming and backflow air increases to twice the initial value, or the CO2 concentration difference between the incoming air and the backflow air decreases to within 30%, it is determined that pollutant desorption is required.

[0107] Specifically, when the pressure difference between the incoming and backflow air increases to twice the initial value, it means that the amount of pollutants condensed inside the freezing chamber 12 and / or the regenerator 24 is large, and the heat exchange channel of the regenerator 24 or the freezing chamber 12 is seriously blocked, resulting in increased airflow resistance, and pollutant desorption is required.

[0108] When the CO2 concentration difference between the incoming air and the return air drops to less than 30%, it means that the pollutant purification efficiency has seriously declined and pollutant desorption is required.

[0109] The judgment logic for the completion of desorption is: when the detection values ​​of the second temperature sensor T2, the third temperature sensor T3, the fourth temperature sensor T4 and the sixth temperature sensor T6 are all greater than the detection value of the first temperature sensor T1 minus 3K, it is determined that the pollutant desorption is completed, and the blower 21 and the desorption heater 31 are turned off.

[0110] Specifically, the detection value of the first temperature sensor T1 minus 3K is used as the reference value. If the temperatures of the second temperature sensor T2, the third temperature sensor T3, the fourth temperature sensor T4 and the sixth temperature sensor T6 are all higher than this reference value, it indicates that the desorption heater 31 has heated the air in the closed circulation pipeline system to a sufficient temperature so that the solid pollutants can be completely vaporized and have been effectively desorbed.

[0111] The emission condition is considered complete when the nitrogen concentration detected by the nitrogen concentration sensor X3 exceeds 99%. This indicates that the system has completely expelled the desorbed gaseous pollutants through nitrogen, and the remaining air is primarily nitrogen. This high nitrogen concentration test confirms that the pollutants have been completely discharged.

[0112] By comprehensively monitoring airflow pressure differences, CO2 concentration differences, and data from multiple temperature sensors, the system achieves intelligent control of the pollutant desorption process. When the system detects conditions requiring desorption, it automatically initiates the process. After desorption and pollutant discharge are complete, the system automatically shuts down related equipment to conserve energy. This multi-parameter, multi-condition combined control enables efficient and safe pollutant desorption and discharge, improving overall operational stability and reliability.

[0113] Compared with traditional purification technologies based on principles such as porous adsorbents and catalysts, which can generally only treat pollutants of specific objects, the purification system and method disclosed in the present invention adopt a low-temperature freezing method to achieve simultaneous liquefaction and freezing purification of multiple pollutants.

[0114] The present invention can realize automatic continuous operation. By setting three working conditions and configuring a series of electric stop valves and electric regulating valves 112, automatic operation can be realized with the support of control logic.

[0115] Frequent replacement of filter media or catalysts is unnecessary; only liquid nitrogen or nitrogen gas needs to be replenished after use. Conventional air purification methods have limited lifespans for adsorbent filter media or catalysts, necessitating frequent replacement. This invention utilizes cryogenic freezing to capture air pollutants, eliminating the need for filter media and catalyst replacement. Liquid nitrogen or nitrogen gas only needs to be replenished when insufficient, as both are mature, inexpensive, and readily available industrial products.

[0116] 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, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An air pollutant purification system, characterized in that: include: A freezing assembly (1) comprises a liquid nitrogen container (11) and a freezing chamber (12), wherein a heat exchange coil (13) is arranged in the freezing chamber (12), wherein the liquid nitrogen container (11) is connected to an inlet end of the heat exchange coil (13), and an outlet end of the heat exchange coil (13) is connected to an exhaust assembly (14) for discharging used nitrogen to the outside of the system through the exhaust assembly (14); An air circulation component (2) comprises a blower (21), a return air duct network (22), a supply air duct network (23) and a regenerator (24); the return air duct network (22) is connected to an air inlet of a freezing chamber (12) via the regenerator (24) and is used to allow air to be purified to pass through the regenerator (24) and enter the freezing chamber (12) to freeze or liquefy gaseous pollutants; an air outlet of the freezing chamber (12) is connected to the supply air duct network (23) via the regenerator (24); the blower (21) is connected in series to the supply air duct network (23); and the supply air duct network (23) is used to return purified air to a control area; A desorption assembly (3) for removing solid contaminants from the low-temperature surfaces of the regenerator (24) and the freezing chamber (12); The exhaust component (4) is used to exhaust the desorbed gaseous pollutants to the outside of the system.

2. The air pollutant purification system according to claim 1, characterized in that: The regenerator (24) is provided with an air intake channel (241) and a first heat exchange channel (242); the return air duct network (22) comprises a return air duct (221), a return air port (224) and a second electric stop valve (223); the inlet end of the return air duct (221) is located in the return air area and is connected to a plurality of return air ports (224); the outlet end of the return air duct (221) is connected to the inlet of the air intake channel (241); the outlet of the air intake channel (241) is connected to the air intake of the freezing chamber (12); and the second electric stop valve (223) is provided on the return air duct (221); The air supply network (23) comprises an air supply pipeline (231), a first electric stop valve (232), a flow meter (233) and an air supply port (234); the inlet end of the air supply pipeline (231) is connected to the outlet of the first heat exchange channel (242); the inlet of the first heat exchange channel (242) is connected to the air outlet of the freezing chamber (12); the outlet end of the air supply pipeline (231) is arranged in the air supply area and is connected to a plurality of air supply ports (234); the air blower (21), the first electric stop valve (232) and the flow meter (233) are arranged in sequence on the air supply pipeline (231) along the air flow direction of the air supply pipeline (231).

3. The air pollutant purification system according to claim 2, characterized in that: The exhaust assembly (14) comprises an exhaust pipeline (141), an exhaust heater (142), a third electric stop valve (143) and a fourth electric stop valve (144); one end of the exhaust pipeline is connected to the outlet end of the heat exchange coil (13), and the other end is used to connect to the external environment of the system; the exhaust heater (142), the third electric stop valve (143) and the fourth electric stop valve (144) are all arranged in sequence on the exhaust pipeline (141) along the air flow direction of the exhaust pipeline (141).

4. The air pollutant purification system according to claim 3, characterized in that: The invention also comprises a precooling pipeline (5), wherein the precooling pipeline (5) comprises a first pipeline (51), a second pipeline (52) and a fifth electric stop valve (53); a second heat exchange channel (243) is also provided in the regenerator (24); one end of the first pipeline (51) is connected to the outlet end of the heat exchange coil (13), and the other end is connected to the inlet of the second heat exchange channel (243); the fifth electric stop valve (53) is provided on the first pipeline (51); one end of the second pipeline (52) is connected to the outlet end of the second heat exchange channel (243), and the other end is connected to the exhaust pipeline (141) between the third electric stop valve (143) and the fourth electric stop valve (144).

5. The air pollutant purification system according to claim 4, characterized in that: The desorption component (3) comprises a desorption heater (31), a desorption cross-tube (32) and a sixth electric stop valve (33); two ends of the desorption cross-tube (32) are respectively connected to the return air pipeline (221) and the supply air pipeline (231); the desorption heater (31) and the sixth electric stop valve (33) are both arranged on the desorption cross-tube (32); The discharge assembly (4) comprises a purge pipeline (41), a nitrogen container (42), a seventh electric stop valve (43), a third pipeline (44), and an eighth electric stop valve (45); the nitrogen container (42) is connected to an air supply pipeline (231) located between a blower (21) and a regenerator (24) through the purge pipeline (41); the seventh electric stop valve (43) is arranged on the purge pipeline (41); one end of the third pipeline (44) is connected to the freezing chamber (12), and the other end is connected to an exhaust pipeline (141) between the third electric stop valve (143) and the fourth electric stop valve (144); and the eighth electric stop valve (45) is arranged on the third pipeline (44).

6. The air pollutant purification system according to claim 5, characterized in that: The liquid nitrogen container (11) is connected to the inlet of the heat exchange coil (13) through a vacuum insulation pipeline (111); an electric regulating valve (112) is also provided on the vacuum insulation pipeline (111); a first temperature sensor (T1) is provided at the inlet end of the return air pipeline (221); a second temperature sensor (T2) is provided at the air inlet of the freezing chamber (12); a third temperature sensor (T3) is provided at the air outlet of the freezing chamber (12); a fourth temperature sensor (T4) is provided in the freezing chamber (12); a fifth temperature sensor (T5) is provided at the outlet of the heat exchange coil (13); and a sixth temperature sensor (T6) is provided at the inlet end of the air supply pipeline (231); An inflow air pressure sensor (P1) and at least one inflow air pollutant concentration sensor (X1) are arranged at one end of the return air pipeline (221) close to the regenerator (24), a return air pressure sensor (P2) and at least one return air pollutant concentration sensor (X2) are arranged at one end of the supply air pipeline (231) close to the regenerator (24), and a nitrogen concentration sensor (X4) is also arranged on the third pipeline (44).

7. A method for purifying air pollutants, which utilizes the air pollutant purification system according to claim 6, characterized in that: The steps include: S1, cooling stage: low-temperature nitrogen in the liquid nitrogen container (11) is introduced into the heat exchange coil (13) of the freezing chamber (12) to provide a low-temperature cooling source for the entire purification system; S2, pre-cooling stage: after the air supply fan (21) is started, the air to be purified in the environment is sucked into the return air duct network (22) and enters the system, and is transported to the regenerator (24), and then enters the freezing chamber (12), and exchanges heat with the heat exchange coil (13) for cooling. The low-temperature air leaves the freezing chamber (12) and enters the regenerator (24), which can cool the regenerator (24) body and the incoming air. At the same time, the return air itself is heated up, leaves the regenerator (24), enters the air supply duct network (23), is transported to the air supply port (234), and returns to the environment. When the air temperature in the freezing chamber (12), the temperature of the regenerator body, the return air temperature, and the incoming air temperature are all reduced to the rated operating point, the air purification stage is entered; S3, air purification stage: the incoming air enters the freezing chamber (12), exchanges heat with the heat exchange coil (13) and cools down, gaseous pollutants in the air are liquefied and frozen on the surface of the heat exchange coil (13) and in the freezing chamber (12), and the air is purified; S4, when the air purification stage reaches a certain time, the heater and the freezing chamber (12) are heated by the desorption component (3) to desorb the pollutants; S5. After the desorption of pollutants is completed, the desorbed air pollutants in the system are replaced by the discharge component (4), and steps S1 to S4 are performed again.

8. The method for purifying air pollutants according to claim 7, characterized in that: When the air inlet temperature of the freezing chamber (12) is greater than 112K, the fourth electric stop valve (144) is opened, and a portion of the low-temperature pre-cooling nitrogen is diverted to the first pipeline (51) through the fourth electric stop valve (144) and enters the regenerator (24), thereby accelerating the cooling process of the regenerator (24); when the air inlet temperature of the freezing chamber (12) is less than or equal to 112K, the fourth electric stop valve (144) is used to stop the supply of low-temperature nitrogen from the pre-cooling pipeline (5) to the regenerator (24).

9. The method for purifying air pollutants according to claim 7, characterized in that: When the detection value of the incoming air pollutant concentration sensor (X1) is less than a set target value, the operating frequency of the air blower (21) is 10% of the rated air volume of the air blower (21); when the detection value of the incoming air pollutant concentration sensor (X1) is less than 20% of the set target value, the operating frequency of the air blower (21) increases exponentially; when the detection value of the incoming air pollutant concentration sensor (X1) is greater than 20% of the set target value, the operating frequency of the air blower (21) increases linearly; when the detection value of the fifth temperature sensor (T5) is less than or equal to 97K, the opening of the electric control valve (112) is 10% of the rated opening; when the detection value of the fifth temperature sensor (T5) is greater than 97K, the opening of the electric control valve (112) increases linearly or exponentially.

10. The method for purifying air pollutants according to claim 7, characterized in that: When the pressure difference between the incoming and backflow air increases to twice the initial value, or the CO2 concentration difference between the incoming and backflow air decreases to less than 30%, it is determined that pollutant desorption is required; when the detection values ​​of the second temperature sensor (T2), the third temperature sensor (T3), the fourth temperature sensor (T4) and the sixth temperature sensor (T6) are all greater than the detection value of the first temperature sensor (T1) minus 3K, it is determined that pollutant desorption is completed, and the air blower (21) and the desorption heater (31) are turned off; when the nitrogen concentration detected by the nitrogen concentration sensor (X4) is greater than 99%, it is determined that pollutant emission is completed.

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