Waste gas purification system and method for lithium battery recovery

Abstract

The invention provides a waste gas purification system and method for lithium battery recovery. The system comprises dust removal equipment, dehumidification equipment, a condensing device, an alkaline washing tower, a water washing tower, demisting equipment, an adsorption device, a fan and heating equipment, the dehumidification equipment comprises a treatment unit and a regeneration unit, an inlet of the treatment unit is connected with the dust removal equipment, the dust removal equipment is connected with the lithium battery disassembling and recycling equipment, and an outlet of the treatment unit is connected with an inlet of the condensing device; an inlet of the regeneration unit is connected with heating equipment which is connected with a fan; an outlet of the regeneration unit is connected with a water scrubber or demisting equipment; the inlet of the alkaline washing tower is connected with the outlet of the condensing device; the outlet of the alkaline washing tower is connected with the inlet of the water washing tower; an inlet of the demisting equipment is connected with an outlet of the water scrubber, and an outlet of the demisting equipment is connected with an inlet of the adsorption device; and an outlet of the adsorption device is used for discharging gas. The problem that in the existing waste gas purification process, strong acid is generated to corrode equipment and process pipelines, and consequently the system cannot operate normally is solved.

Description

Technical Field

[0001] The present application relates to the technical field of waste gas purification, and in particular to a waste gas purification system and method for recycling lithium batteries. Background Art

[0002] With the popularity of new energy vehicles, the use of power lithium batteries has also doubled. However, with the increase in the number of years of use, the replacement of power lithium batteries has also gradually increased. The replaced lithium batteries need to be recycled and the batteries must be disassembled and the materials must be classified and recycled. During the disassembly process, a large amount of organic solvents are volatilized. If these organic solvents are not treated, they will seriously pollute the environment.

[0003] Traditional methods for treating organic waste gas mainly include combustion, condensation, adsorption, corona and plasma purification. Since battery disassembly waste gas contains halogen elements, combustion will produce carcinogenic dioxins and other substances, and the strong acid formed by halogen elements will corrode the combustion equipment. During condensation recovery, PF5 in the waste gas will inevitably react with the liquid water condensed in the waste gas to form HF, which will aggravate corrosion and cannot operate safely and stably. Since the concentration of organic waste gas generated during the disassembly process is relatively high, the use of adsorption alone will cause the adsorbent to be penetrated in a short time and cannot operate stably for a long time. The corona method and plasma purification method are only suitable for low-concentration waste gas purification, and the purification efficiency of high-concentration waste gas is extremely low and cannot achieve the treatment effect. In the above treatment processes, there is a deficiency that the fluoride in the waste gas meets water to form a strong acid to corrode the equipment and process pipelines, causing the system to be unable to operate normally. Summary of the invention

[0004] The embodiments of the present application provide a waste gas purification system and method for lithium battery recycling, which solves the problem that strong acid will corrode equipment and process pipelines in the existing waste gas purification process, causing the system to be unable to operate normally.

[0005] The present invention is implemented as follows: a waste gas purification system for lithium battery recycling includes dust removal equipment, dehumidification equipment, condensing device, alkali washing tower, water washing tower, demisting equipment, adsorption device, fan and heating equipment; the dehumidification equipment includes a processing unit and a regeneration unit, the inlet of the processing unit is connected to the dust removal equipment, the dust removal equipment is used to connect to the lithium battery disassembly and recycling equipment, and the outlet of the processing unit is connected to the inlet of the condensing device; the inlet of the regeneration unit is connected to the heating equipment, and the heating equipment is connected to the fan; the outlet of the regeneration unit is connected to the water washing tower or the demisting equipment; the inlet of the alkali washing tower is connected to the outlet of the condensing device, and the outlet of the alkali washing tower is connected to the inlet of the water washing tower; the inlet of the demisting equipment is connected to the outlet of the water washing tower, and the outlet of the demisting equipment is connected to the inlet of the adsorption device; the outlet of the adsorption device is used to discharge gas.

[0006] In one embodiment, the dehumidification equipment is a molecular sieve dehumidifier.

[0007] In one embodiment, the dehumidification equipment includes a first molecular sieve adsorption tower and a second molecular sieve adsorption tower which are arranged in parallel and are both connected to a switching device, and the switching device is used to switch the working state of the first molecular sieve adsorption tower and the second molecular sieve adsorption tower; wherein the working state includes a processing unit state and a regeneration unit state.

[0008] In one of the embodiments, the outlet of the demisting device is connected to the inlet of the water washing tower, so as to transfer the water enriched in the demisting device to the water washing tower.

[0009] In one embodiment, the dust removal equipment is a bag dust collector or a multi-tube parallel cyclone dust collector.

[0010] In one embodiment, the condensing device includes a primary condenser, a secondary condenser, a condensing unit and a gas-liquid separator;

[0011] The inlet of the primary condenser is connected to the processing unit, and the secondary condenser is connected in series with the primary condenser and is connected to the condensing unit;

[0012] The first-stage condenser and the second-stage condenser are both connected to the inlet of the gas-liquid separator for sending the condensate to the gas-liquid separator. The outlet of the gas-liquid separator is connected to the second-stage condenser for sending the volatile gas of the gas-liquid separator into the second-stage condenser for deep condensation. The temperature of the exhaust gas passing through the condensation device is ≤-20°C.

[0013] In one embodiment, the adsorption device comprises two fixed adsorption beds connected in parallel, wherein one of the fixed adsorption beds is used while the other fixed adsorption bed is kept activated and regenerated for standby;

[0014] The fixed adsorption bed is connected to a desorption device for desorbing and discharging the waste gas from the fixed adsorption bed.

[0015] In one of the embodiments, the waste gas purification system for lithium battery recycling further includes a catalytic burner, which is connected to the outlet of the fixed adsorption bed and is used for catalytically thermally decomposing the desorbed waste gas and then emitting it cleanly.

[0016] The present application also provides a method for purifying waste gas from lithium battery recycling, which is applied to the waste gas purification system for lithium battery recycling as described in any of the above embodiments, and includes the following steps:

[0017] Dust removal step: The waste gas generated by the lithium battery disassembly and recycling equipment enters the dust removal equipment to remove the powder particles entrained in the air flow;

[0018] Drying step: the gas after dust removal enters the dehumidification equipment, and the processing unit of the dehumidification equipment absorbs the moisture in the gas, so that the dew point of the dried gas is lower than -40°C; the clean air heated to 60°C by the heating equipment enters the regeneration unit of the dehumidification equipment, absorbs the moisture absorbed by the processing unit of the dehumidification equipment, and then is sent to the water scrubber or demisting equipment;

[0019] Condensation recovery step: the dried gas enters the condensation device, condenses the gas to ≤-20°C, and condenses the organic solvent in the gas;

[0020] Alkali washing step: the gas after the organic solvent is precipitated enters the alkali washing tower and is washed with Ca(OH)2 or NaOH solution to remove the acidic substances in the gas;

[0021] Water washing step: the gas after alkali washing enters the water washing tower, and the alkali liquid and residue in the gas are removed by water washing;

[0022] Demisting step: The gas after water washing enters the demisting equipment, and the droplets are separated from the gas by centrifugal force and enriched in the lower part of the demisting equipment;

[0023] Adsorption step: The defogged gas enters the adsorption device to adsorb the organic matter in the gas.

[0024] In one of the embodiments, the demisting step is specifically as follows: the gas after water washing enters the demisting equipment, the droplets are separated from the gas by centrifugal force, and are enriched at the bottom of the demisting equipment; the enriched water is sent to the water washing tower.

[0025] In one of the embodiments, the adsorption step is specifically as follows: the defogged gas enters two fixed adsorption beds of the adsorption device, and according to a preset time period, the two fixed adsorption beds alternately adsorb and desorb organic matter in the gas. After meeting the emission standards, the gas is discharged through the outlet of the adsorption device.

[0026] In one embodiment, the desorption method in the adsorption step is: using heated nitrogen or water vapor to regenerate and desorb the activated carbon of the fixed adsorption bed.

[0027] In one embodiment, the waste gas purification method for lithium battery recycling further includes the following steps:

[0028] Catalytic combustion step: the desorbed exhaust gas enters the catalytic combustor for catalytic thermal decomposition and then is discharged cleanly.

[0029] An embodiment of the present application also provides a waste gas purification system for lithium battery recycling, comprising an alkali washing tower, a water washing tower, a demisting device, a dust removal device, a dehumidifying device, a condensing device, an adsorption device, a fan and a heating device; the inlet of the water washing tower is connected to the outlet of the alkali washing tower, the inlet of the alkali washing tower is used to connect to the lithium battery disassembly and recycling equipment, and the outlet of the water washing tower is connected to the inlet of the demisting device; the dehumidifying equipment comprises a processing unit and a regeneration unit, the inlet of the processing unit is connected to the dust removal device, the dust removal device is used to connect to the outlet of the demisting device, and the outlet of the processing unit is connected to the inlet of the condensing device; the inlet of the regeneration unit is connected to the heating device, and the heating device is connected to the fan; the outlet of the regeneration unit is connected to the water washing tower or the demisting device; the outlet of the condensing device is connected to the inlet of the adsorption device; the outlet of the adsorption device is used to discharge gas.

[0030] The present application also provides a method for purifying waste gas from lithium battery recycling, which is applied to the waste gas purification system for lithium battery recycling as described in any of the above embodiments, and includes the following steps:

[0031] Alkaline washing step: the waste gas generated by the lithium battery disassembly and recycling equipment enters the alkaline washing tower and is washed with Ca(OH)2 or NaOH solution to remove the acidic substances in the waste gas;

[0032] Water washing step: the gas after alkali washing enters the water washing tower, and the alkali liquid and residue in the gas are removed by water washing;

[0033] Demisting step: The gas after water washing enters the demisting equipment, and the droplets are separated from the gas by centrifugal force and enriched in the lower part of the demisting equipment;

[0034] Dust removal step: The demisted gas enters the dust removal equipment to remove the powder particles entrained in the airflow;

[0035] Drying step: the gas after dust removal enters the dehumidification equipment, and the processing unit of the dehumidification equipment absorbs the moisture in the gas, so that the dew point of the dried gas is lower than -40°C; the clean air heated to 60°C by the heating equipment enters the regeneration unit of the dehumidification equipment, absorbs the moisture absorbed by the processing unit of the dehumidification equipment, and then is sent to the water scrubber or demisting equipment;

[0036] Condensation recovery step: the dried gas enters the condensation device, condenses the gas to ≤-20°C, and condenses the organic solvent in the gas;

[0037] Adsorption step: The gas after the organic solvent is precipitated enters the adsorption device to adsorb the organic matter in the gas.

[0038] The beneficial effects of the waste gas purification system and method for lithium battery recycling provided by the present application are as follows: compared with the prior art, the present application does not introduce moisture during the entire waste gas treatment process, and dries the waste gas at the same time, effectively avoiding the halogen in the waste gas from forming strong acid corrosion equipment when it meets water, causing the process to be unable to operate normally; and adopts dust removal, condensation, alkali washing, water washing, demisting and adsorption and other different treatment steps to process and collect different substances in the waste gas, and adopts different recycling and treatment processes according to different waste gas characteristics, so as to make the recycling more efficient and more adaptable to the unstable working conditions of the enterprise's waste gas emissions, so as to reasonably optimize the energy consumption of the whole set of equipment; in addition, the dew point of the dried waste gas is lower than the cooling temperature of the condensing device, and then the condensing device is used to recover most of the organic solvents, which is conducive to reducing carbon emissions and realizing a green circular economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of the waste gas purification system for lithium battery recycling provided in Example 1 of the present application;

[0040] Figure 2 It is a structural schematic diagram of the waste gas purification system for lithium battery recycling provided in Example 2 of the present application;

[0041] Figure 3 It is a structural schematic diagram of the waste gas purification system for lithium battery recycling provided in Example 3 of the present application;

[0042] Figure 4 This is another structural schematic diagram of the waste gas purification system for lithium battery recycling provided in Example 3 of the present application;

[0043] Figure 5 It is a structural schematic diagram of the waste gas purification system for lithium battery recycling provided in Example 4 of the present application;

[0044] Figure 6 It is a structural schematic diagram of the waste gas purification system for lithium battery recycling provided in Example 5 of the present application;

[0045] Figure 7 This is a schematic diagram of the structure of the waste gas purification system for lithium battery recycling provided in Example 6 of the present application;

[0046] Figure 8 This is a schematic diagram of the process of the waste gas purification method for lithium battery recycling provided in Example 7 of the present application;

[0047] Fig. 9 This is a schematic diagram of a specific process of the waste gas purification method for lithium battery recycling provided in Example 7 of the present application;

[0048] Fig.10 It is a structural schematic diagram of the waste gas purification system for lithium battery recycling provided in Example 8 of the present application;

[0049] Fig.11 It is a flow chart of the waste gas purification method for lithium battery recycling provided in Example 9 of the present application.

[0050] Reference numerals: 100, lithium battery disassembly and recycling equipment; 1, dust removal equipment;

[0051] 2. Dehumidification equipment; 21. Processing unit; 22. Regeneration unit; 20. Switching device; 201. First molecular sieve adsorption tower; 202. Second molecular sieve adsorption tower;

[0052] 3. Condensation device; 31. Primary condenser; 32. Secondary condenser; 33. Condensing unit; 34. Gas-liquid separator;

[0053] 4. Alkali washing tower; 5. Water washing tower; 6. Demisting equipment; 7. Adsorption device; 8. Fan; 9. Heating equipment; 10. Catalytic burner. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0055] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0056] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply 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 a limitation on the present application.

[0057] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0058] It should also be noted that, in the embodiments of the present application, the same figure mark is used to represent the same component or the same part. For the same parts in the embodiments of the present application, the figure may only mark one of the parts or components as an example. It should be understood that the figure mark also applies to other identical parts or components.

[0059] The embodiments of the present application provide a waste gas purification system and method for lithium battery recycling, which solves the problem that strong acid will corrode equipment and process pipelines in the existing waste gas purification process, causing the system to be unable to operate normally.

[0060] Embodiment 1

[0061] refer to Figure 1 The waste gas purification system for lithium battery recycling provided in Example 1 of the present application includes a dust removal device 1, a dehumidification device 2, a condensing device 3, an alkali washing tower 4, a water washing tower 5, a demisting device 6, an adsorption device 7, a fan 8 and a heating device 9; the dehumidification device 2 includes a processing unit 21 and a regeneration unit 22, the inlet of the processing unit 21 is connected to the dust removal device 1, the dust removal device 1 is used to connect the lithium battery disassembly and recycling equipment 100, and the outlet of the processing unit 21 is connected to the inlet of the condensing device 3; the inlet of the regeneration unit 22 is connected to the heating device 9, and the heating device 9 is connected to the fan 8; the outlet of the regeneration unit 22 is connected to the water washing tower 5; the inlet of the alkali washing tower 4 is connected to the outlet of the condensing device 3, and the outlet of the alkali washing tower 4 is connected to the inlet of the water washing tower 5; the inlet of the demisting device 6 is connected to the outlet of the water washing tower 5, and the outlet of the demisting device 6 is connected to the inlet of the adsorption device 7; the outlet of the adsorption device 7 is used to discharge gas.

[0062] The waste gas purification system for lithium battery recycling provided in Example 1 of the present application is mainly used to treat the waste gas generated during the disassembly and recycling process of lithium batteries, wherein the above-mentioned lithium battery disassembly and recycling equipment 100 may include but is not limited to an unpacking device, a crushing device and an electrolyte drying device.

[0063] In Example 1 of the present application, the waste gas generated by the lithium battery disassembly and recycling equipment 100 passes through the dust removal equipment 1 to remove the powdery particles in the waste gas, passes through the dehumidification equipment 2 for drying, passes through the condensation device 3 to condense and precipitate the organic solvent in the waste gas, passes through the alkali washing tower 4 to neutralize the acidic substances in the waste gas, passes through the water washing tower 5 to remove the alkali liquid and residue in the waste gas, passes through the demister to remove the moisture in the waste gas, and finally passes through the adsorption equipment to adsorb the organic matter in the waste gas so as to discharge clean gas. During the entire waste gas purification process, each processing step is processed separately, and different recycling and processing processes can be used to recycle and process different harmful substances in the waste gas. Not only is the recycling more efficient, but it is also more adaptable to the unstable working conditions of the enterprise's waste gas emissions, so as to reasonably optimize the energy consumption of the entire set of equipment.

[0064] In addition, during the entire waste gas treatment process, not only is no additional moisture introduced, but the waste gas is also dried by the dehumidification equipment 2, which solves the problem that the halogen in the waste gas forms a strong acid when it meets water and corrodes the equipment, causing the process to be unable to operate normally; the dew point of the dried waste gas is lower than the cooling temperature of the condensing device 3, and the condensing device 3 is used to recover most of the organic solvent, thereby reducing carbon emissions and realizing a green circular economy.

[0065] The dehumidification equipment 2 of the first embodiment of the present application includes a processing unit 21 and a regeneration unit 22. The processing unit 21 can absorb moisture in the exhaust gas entering the dehumidification unit to dry the exhaust gas. At the same time, the regeneration unit 22 is connected to the heating device 9. The fan 8 connected to the heating device 9 will send the clean air from the outside into the heating device 9 for heating. The heated clean air enters the dehumidification equipment 2. The regeneration unit 22 of the dehumidification equipment 2 can be used to make the heated clean air absorb the moisture in the exhaust gas. Then, the clean air containing moisture is introduced into the water washing tower 5 to replenish moisture for the water washing tower 5. This can reduce the amount of industrial water used in the water washing tower 5 and recycle the moisture in the exhaust gas.

[0066] In some embodiments, the dust removal equipment 1 can be a bag dust collector or a multi-tube parallel cyclone dust collector, which is not specifically limited in the embodiments of the present application. When a multi-tube parallel cyclone dust collector is used as the dust removal equipment 1, the dust removal equipment 1 can be made of abrasion-resistant and corrosion-resistant materials to prevent the corrosion of lithium hexafluorophosphate to form strong acid when it comes into contact with water. The dust removal mechanism is to make the dust-laden airflow rotate, and use centrifugal force to separate the dust particles from the airflow and capture them on the wall of the device, and then use gravity to make the dust particles fall into the collector. It is suitable for the removal of non-sticky and non-fibrous dust, and is mostly used to remove particles larger than 5μm. The multi-tube parallel cyclone dust collector also has a dust removal efficiency of 80-85% for particles of 3μm, which can better ensure the safety, stability and efficiency of subsequent processing processes.

[0067] Since the exhaust gas needs to be deeply condensed to ≤-20°C, and the collected exhaust gas contains a large amount of moisture, this moisture will not only frost and freeze during condensation, causing blockage in the gas channel, but also these moisture will ionize when encountering electrolytes such as lithium hexafluorophosphate in the electrolyte to produce strong acid, causing serious corrosion to the equipment. Therefore, a dehumidification device 2 is provided in the exhaust gas purification system for lithium battery recycling in Example 1 of the present application, and the dehumidification device 2 includes a treatment unit 21 and a regeneration unit 22, wherein the treatment unit 21 can adsorb moisture in the exhaust gas entering the dehumidification device 2, so that the exhaust gas discharged from the dehumidification device 2 is dry, ensuring that the entire exhaust gas purification system for lithium battery recycling is carried out smoothly and orderly, and there will be no problem that the halogen in the exhaust gas will form a strong acid when it meets water to corrode the equipment, causing the process to be unable to operate normally.

[0068] In some embodiments, reference Figure 1, the dehumidification equipment 2 is a molecular sieve dehumidifier; when the exhaust gas after dust removal by the dust removal equipment 1 enters the molecular sieve dehumidifier, the molecular sieve of the molecular sieve dehumidifier will absorb moisture in the exhaust gas, making the dew point of the dried gas lower than -40°.

[0069] In some embodiments, reference Figure 1 The condensing device 3 includes a primary condenser 31, a secondary condenser 32, a condensing unit 33 and a gas-liquid separator 34; the inlet of the primary condenser 31 is connected to the processing unit 21, the secondary condenser 32 is connected in series with the primary condenser 31, and is connected to the condensing unit 33; the primary condenser 31 and the secondary condenser 32 are both connected to the inlet of the gas-liquid separator 34 for sending the condensate to the gas-liquid separator 34, and the outlet of the gas-liquid separator 34 is connected to the secondary condenser 32 for sending the volatile gas of the gas-liquid separator 34 to the secondary condenser 32 for deep condensation, and the temperature of the exhaust gas passing through the condensing device 3 is ≤-20°C.

[0070] The condensing device 3 is mainly used for the waste gas discharged by the lithium battery disassembly and recycling equipment 100 when processing lithium batteries. The main component of these waste gases is an electrolyte composed of carbonates in proportion, which is characterized by a relatively high concentration. According to the saturated vapor pressure data in its physical properties, most of the organic solvents can be recovered by condensing the waste gas to ≤-20°C. Therefore, the condensing device 3 includes a two-stage condenser and a gas-liquid separator 34, which are used to condense and precipitate the organic solvent in the gas. After the gas-liquid separator 34 precipitates the organic solution, it can be recovered manually. Of course, a recovery pipeline can also be connected to the organic solvent precipitation outlet of the gas-liquid separator 34 to realize automatic recovery of the organic solvent.

[0071] Specifically, the dried waste gas enters the condensing device 3, to be precise, first enters the primary condenser 31, cools the waste gas to 5°C ~ 8°C, and then enters the secondary condenser 32, cools the waste gas to ≤-20°C, and the condensate precipitated during the condensation process is sent to the gas-liquid separator 34, the gas-liquid separator 34 precipitates the organic solution in the condensate for recovery and treatment, and at the same time, the volatile gas generated by the gas-liquid separator 34 continues to be sent to the secondary condenser 32 for deep condensation. Since the secondary condenser 32 is connected to the condensing unit 33, the waste gas discharged from the secondary condenser 32 is used as the cold source of the primary condenser 31. Since the inlet of the primary condenser 31 is connected to the dried waste gas, the waste gas discharged from the secondary condenser 32 will be heated to room temperature after encountering the dried waste gas, and then enters the alkali washing tower 4, so that the cooled waste gas can be prevented from directly entering the alkali washing tower 4 to cause the condensation of the alkali washing liquid and affect normal use.

[0072] In some embodiments, reference Figure 1 The outlet of the demister 6 is connected to the inlet of the water washing tower 5 so as to transfer the water enriched inside the demister 6 to the water washing tower 5 .

[0073] It should be noted that the waste gas after water washing contains a large amount of moisture. If it directly enters the adsorption device 7 to adsorb organic matter in the waste gas, it will greatly affect the adsorption efficiency of the adsorption device 7 for organic matter. Therefore, the moisture in the waste gas needs to be removed before the waste gas is connected to the adsorption device 7. The present application sets a defogger 6 between the water washing tower 5 and the adsorption device 7, and connects the waste gas after water washing to the defogger 6. The defogger 6 in the present application adopts a multi-tube centrifugal device or a multi-layered baffle plate to change the flow direction of the airflow, and uses centrifugal force to separate droplets from the waste gas and enrich them at the bottom of the demister. In this way, the moisture in the waste gas can be removed first, and then it is sent to the adsorption device 7 to adsorb the organic matter in the waste gas.

[0074] It is understandable that the water washing process in the water washing tower 5 requires industrial water, which requires manual addition of industrial water to the water washing tower 5. In Example 1 of the present application, the outlet of the defogger 6 is connected to the inlet of the water washing tower 5, so that the water enriched in the lower part of the defogger 6 can be transmitted to the water washing tower 5, thereby replenishing water in the water washing tower 5. This not only eliminates the need for manual addition of industrial water to the water washing tower 5, reducing workload, but also saves costs. At the same time, the waste gas is washed with water through the water washing tower 5 to absorb moisture, and then the moisture is removed through the defogger 6. Finally, the water enriched in the lower part of the defogger 6 is transmitted to the water washing tower 5, thereby realizing the recycling of water, which is conducive to the realization of a green circular economy.

[0075] Embodiment 2

[0076] refer to Figure 2 The waste gas purification system for lithium battery recycling of the second embodiment of the present application is different from that of the first embodiment only in that the outlet of the regeneration unit 22 is connected to the defogger 6. That is, the clean air containing moisture is introduced into the defogger 6 for direct defog, so that the moisture in the waste gas can be processed, ensuring the smooth operation of the waste gas purification system for lithium battery recycling.

[0077] In the second embodiment of the present application, the outlet of the regeneration unit 22 is connected to the defogger 6. At this time, the water enriched inside the defogger 6 includes not only the moisture in the exhaust gas after washing by the water washing tower 5, but also the moisture in the clean air containing moisture discharged by the regeneration unit 22. The moisture in the clean air containing moisture discharged by the regeneration unit 22 is also the moisture in the adsorbed exhaust gas. Therefore, the defogger 6 transfers the water enriched inside it to the water washing tower 5, which can not only fully replenish the moisture for the water washing tower 5, but also recycle the moisture in the exhaust gas purification process.

[0078] Embodiment 3

[0079] refer to Figure 3Compared with the waste gas purification system for lithium battery recycling in Example 3 of the present application, the difference lies in the dehumidification equipment 2. In Example 3 of the present application, the dehumidification equipment 2 includes a first molecular sieve adsorption tower 201 and a second molecular sieve adsorption tower 202 which are arranged in parallel and are both connected to a switching device 20. The switching device 20 is used to switch the working state of the first molecular sieve adsorption tower 201 and the second molecular sieve adsorption tower 202; wherein the working state includes a processing unit state and a regeneration unit state.

[0080] Specifically, the inlet and outlet of the first molecular sieve adsorption tower 201 are respectively connected to the switching device 20. Similarly, the inlet and outlet of the second molecular sieve adsorption tower 202 are also respectively connected to the switching device 20. When the first molecular sieve adsorption tower 201 is in use, the second molecular sieve adsorption tower 202 is kept activated and regenerated for standby. When the second molecular sieve adsorption tower 202 is in use, the first molecular sieve adsorption tower 201 is kept activated and regenerated for standby. The molecular sieves in the first molecular sieve adsorption tower 201 and the second molecular sieve adsorption tower 202 only adsorb moisture to ensure that the entire system is carried out smoothly and orderly. After a certain amount of waste gas passes through the first molecular sieve adsorption tower 201, the first molecular sieve adsorption tower 201 is closed, the first molecular sieve adsorption tower 201 is activated and regenerated for standby, the switching device 20 is started, and the subsequent waste gas enters the second molecular sieve adsorption tower 202 for moisture adsorption.

[0081] It should be noted that when the tooling state of the first molecular sieve adsorption tower 201 is the processing unit state and the working state of the second molecular sieve adsorption tower 202 is the regeneration unit state, the first molecular sieve adsorption tower 201 is equivalent to the processing unit 21 of the dehumidification equipment 2, which is used to adsorb moisture in the exhaust gas after dust removal, and the second molecular sieve adsorption tower 202 is equivalent to the regeneration unit 22 of the dehumidification equipment 2, which is used to make the moisture adsorbed by the first molecular sieve adsorption tower 201 adsorbed and discharged by the clean air heated by the heating equipment 9, so as to achieve the purpose of drying the exhaust gas.

[0082] refer to Figure 4 Another structure of the waste gas purification system for lithium battery recycling in Example 3 of the present application may be to change the structure of the dehumidification device 2 on the basis of Example 2, that is, to use a first molecular sieve adsorption tower 201 and a second molecular sieve adsorption tower 202 which are arranged in parallel and are both connected to a switching device 20 as the dehumidification device 2, but the outlet of the first molecular sieve adsorption tower 201 or the second molecular sieve adsorption tower 202 which is in the regeneration unit state is connected to the defogger 6 for direct defogger.

[0083] Embodiment 4

[0084] refer to Figure 5The waste gas purification system for lithium battery recycling in the fourth embodiment of the present application is different from that in the third embodiment in that the exhaust gas is discharged in a different manner after the adsorption device 7 adsorbs organic matter in the exhaust gas. In the fourth embodiment of the present application, the waste gas purification system for lithium battery recycling also includes a catalytic burner 10, which is connected to the outlet of the adsorption device 7 and is used to catalytically thermally decompose the desorbed exhaust gas and then discharge it cleanly.

[0085] It should be noted that the adsorption device 7 in the waste gas purification system for lithium battery recovery in Examples 1 to 4 all includes a fixed adsorption bed. In Examples 1 to 3, when the organic matter adsorbed by the fixed adsorption bed reaches a saturated state, that is, the adsorbent of the fixed adsorption bed is full of organic matter, the fixed adsorption bed can be manually transported away and replaced with a new fixed adsorption bed that has not yet adsorbed organic matter. The transported fixed adsorption beds can be concentrated in the urban green island for centralized desorption, so that multiple fixed adsorption beds can be desorbed at the same time to improve the desorption efficiency; of course, when the adsorbent of the fixed adsorption bed is full of organic matter, the adsorbent in the fixed adsorption bed can also be replaced. In actual application, the cycle of replacing the adsorbent in the fixed adsorption bed can be planned according to the time required for the adsorbent of the fixed adsorption bed to be full of organic matter. For example, the adsorbent in the fixed adsorption bed can be replaced once every three months or a fixed period of time, so that the fixed adsorption bed can continuously adsorb organic matter in the waste gas, which is conducive to meeting the emission standards when the waste gas is discharged.

[0086] In the fourth embodiment of the present application, a fixed adsorption bed is connected to a catalytic burner 10. When the adsorbent in the fixed adsorption bed is full of organic matter, the organic matter adsorbed by the fixed adsorption bed can be desorbed, and the desorbed organic-containing waste gas is sent to the catalytic burner 10 for catalytic thermal decomposition, and then the clean gas is discharged.

[0087] Among them, adsorption refers to the phenomenon that molecules or ions are adsorbed onto the solid surface due to the existence of interaction forces when an object contacts the solid surface. The adsorption process is the process of transferring an object from the gas phase or liquid phase to the solid phase. According to the nature of the adsorption force, adsorption can be divided into physical adsorption and chemical adsorption. Physical adsorption is the adsorption caused by the interaction of intermolecular forces. For example, the adsorption of gas by activated carbon, physical adsorption is generally carried out at low temperature, with fast adsorption speed, small adsorption heat, and non-selective adsorption. Chemical adsorption is caused by the chemical bond between the adsorbate and the adsorbent. Like a chemical reaction, adsorption is often irreversible, and the adsorption heat is usually large.

[0088] Desorption is the reverse process of adsorption. It is the process of allowing the adsorbed components to precipitate from the saturated adsorbent and regenerate the adsorbent. It is also called desorption, that is, the process in which the substances adsorbed on the interface escape from the interface and re-enter the bulk phase under certain conditions.

[0089] Generally speaking, conditions that are not conducive to adsorption are often favorable to desorption, such as heating, decompression, etc. Physical adsorption is reversible, and the properties of the adsorbed molecules remain unchanged after desorption. Chemical adsorption is irreversible, desorption often requires activation energy, and the properties of the desorbed molecules often change. Therefore, the fixed adsorption bed of the present application can choose to physically adsorb organic matter, and activated carbon can be used as the adsorbent of the fixed adsorption bed.

[0090] It should be noted that when the fixed adsorption bed changes from an adsorption state to a desorption state, the adsorbent of the fixed adsorption bed needs to be heated. Optionally, a heater can be connected next to the fixed adsorption bed. When the state of the fixed adsorption bed needs to be changed, the adsorbent of the fixed adsorption bed is heated to change the adsorption state of the fixed adsorption bed to a desorption state, and the organic matter adsorbed by the adsorbent of the fixed adsorption bed is desorbed, thereby regenerating the adsorbent of the fixed adsorption bed and re-adsorbing the organic matter in the exhaust gas. In this way, there is no need to regularly replace the fixed adsorption bed, which greatly reduces the workload.

[0091] The catalytic burner 10 can be a catalytic combustion furnace, which is also called a catalytic combustion incinerator or a catalyst incinerator. The catalytic combustion method is used to completely convert harmful organic waste gas into harmless substances under flameless and low temperature conditions (the combustion reaction temperature is generally 250-500°C). The heat during combustion can be self-sufficient or only a small amount of heat needs to be added. The discharged waste heat can be recycled and utilized. The characteristics of the catalytic combustion method are: low ignition temperature, generally 200-280°C, short reaction time, high purification efficiency, and thus saving a lot of energy.

[0092] Embodiment 5

[0093] refer to Figure 6 The waste gas purification system for lithium battery recycling in Example 5 of the present application is different from that in Example 3 in that the structure of the adsorption device 7 is different. In Example 5 of the present application, the adsorption device 7 includes two fixed adsorption beds connected in parallel, wherein one fixed adsorption bed is kept activated and regenerated for standby use while the other fixed adsorption bed is in use.

[0094] It should be noted that the two fixed adsorption beds are used in turn. After the adsorbent of one of the fixed adsorption beds is full of organic matter, the same treatment method as one of the fixed adsorption beds in Example 3 is adopted, that is, the fixed adsorption bed full of organic matter is transported away and centrally desorbed, or the adsorbent for the fixed adsorption bed is replaced regularly. When one of the fixed adsorption beds full of organic matter is treated, the other fixed adsorption bed that is kept activated and regenerated as standby can be opened to adsorb organic matter. In this way, the two fixed adsorption beds take turns to adsorb organic matter, which can achieve the effect of continuous and uninterrupted adsorption of organic matter, thereby improving the treatment efficiency of waste gas.

[0095] Embodiment 6

[0096] refer to Figure 7 Compared with the fourth embodiment, the waste gas purification system for lithium battery recycling in the sixth embodiment of the present application is different in that the structure of the adsorption device 7 is different. In the sixth embodiment of the present application, the adsorption device 7 includes two fixed adsorption beds connected in parallel, one of which is used while the other is kept activated and regenerated for standby; the fixed adsorption bed is connected to a desorption device for desorbing and discharging the waste gas from the fixed adsorption bed. In this way, the organic matter in the waste gas can be continuously adsorbed to achieve a high-efficiency waste gas purification effect.

[0097] Among them, the adsorbent of the fixed adsorption bed can be activated carbon, and the activated carbon can be used to adsorb the organic solvent, and the solvent can be further recovered to make the exhaust meet the national environmental protection standards. Optionally, before the above-mentioned waste gas enters the activated carbon, it can be mixed by a silent mixer to make the waste gas with different organic matter concentrations mixed evenly, which is conducive to the adsorption of activated carbon.

[0098] As the adsorbent accumulates over time, the efficiency and adsorption amount will slowly decrease. Before the efficiency drops to the national emission standard, the activated carbon needs to be regenerated. Therefore, the fixed adsorption bed is connected with a desorption device, which is equivalent to a heater, used to heat the activated carbon to desorb and regenerate the activated carbon. The desorption device can use a hot nitrogen desorption device, and use heated nitrogen to desorb and regenerate the activated carbon, avoiding the possibility of activated carbon ignition caused by hot dry air desorption. The fixed adsorption bed is connected with a gas channel, through which the desorbed exhaust gas is sent to the catalytic burner 10 for catalytic thermal decomposition, so as to discharge clean gas that meets the standards.

[0099] In Example 6 of the present application, the fixed adsorption bed is connected to the desorption equipment in order to activate and regenerate the activated carbon of the fixed adsorption bed. Therefore, the clean air heated by the heating equipment 9 can be sent to the fixed adsorption bed to heat the activated carbon. In this way, there is no need to set up a special desorption equipment, saving costs and resources. In addition, the heat of the clean air heated by the heating equipment 9 can be fully utilized, and the resource utilization rate is greatly improved.

[0100] Embodiment 7

[0101] refer to Figure 8 Embodiment 7 of the present application provides a method for purifying waste gas from lithium battery recycling, which is applied to the waste gas purification system for lithium battery recycling in the above embodiments 1 to 6, and includes the following steps:

[0102] S101, dust removal step: the waste gas generated by the lithium battery disassembly and recycling equipment 100 enters the dust removal equipment 1 to remove the powder particles entrained in the air flow.

[0103] S102, drying step: the gas after dust removal enters the dehumidification equipment 2, and the processing unit 21 of the dehumidification equipment 2 adsorbs moisture in the gas to make the dew point of the dried gas lower than -40°C; the clean air heated to 60°C by the heating equipment 9 enters the regeneration unit 22 of the dehumidification equipment 2, adsorbs the moisture adsorbed by the processing unit 21 of the dehumidification equipment 2, and then is sent to the water washing tower 5 or the demisting equipment 6.

[0104] S103, condensation recovery step: the dried gas enters the condensation device 3, and the gas is condensed to ≤-20°C, so that the organic solvent in the gas is condensed and precipitated.

[0105] S104, alkali washing step: the gas after the organic solvent is precipitated enters the alkali washing tower 4, and is washed with Ca(OH) 2 Or NaOH solution washing to remove acidic substances in the gas.

[0106] S105, water washing step: the gas after alkali washing enters the water washing tower 5, and the alkali liquid and residue in the gas are removed by water washing.

[0107] S106, defog step: the gas after water washing enters the defogger 6, and the liquid droplets are separated from the gas by centrifugal force and are enriched in the lower part of the defogger 6.

[0108] Specifically, the water enriched in the lower part of the defogger 6 can be sent to the water washing tower 5. Since the water washing tower 5 needs to add industrial water to wash the exhaust gas, the water sent from the defogger 6 to the water washing tower 5 can replenish water for the water washing tower 5, which can reduce the amount of water manually replenished for the water washing tower 5, which not only reduces the workload, but also can recycle the water enriched in the lower part of the defogger 6.

[0109] S107, adsorption step: the defogged gas enters the adsorption device 7 to adsorb organic matter in the gas.

[0110] Specifically, the defogged gas enters the two fixed adsorption beds of the adsorption device 7. According to a preset time period, the two fixed adsorption beds alternately adsorb and desorb the organic matter in the gas. After reaching the emission standard, the gas is discharged through the outlet of the adsorption device 7.

[0111] During actual treatment, one of the two fixed adsorption beds remains in working condition to adsorb organic matter in the exhaust gas, and the other remains activated and in standby. When exhaust gas penetration occurs in the fixed adsorption bed that remains in working condition, that is, the adsorbent of the fixed adsorption bed that remains in working condition is full of organic matter, the working condition of the fixed adsorption bed can be stopped at this time, and it can be desorbed and regenerated, while the other standby fixed adsorption bed remains in working condition to continue to adsorb organic matter in the exhaust gas.

[0112] It is understandable that the adsorption state of the adsorbent of the fixed adsorption bed can be monitored by a monitor, and the readings on the monitoring instrument can be read to intuitively determine whether the fixed adsorption bed has exhaust gas penetration. If exhaust gas penetration occurs, the state of the two fixed adsorption beds can be changed, that is, adsorption changes to desorption, and desorption changes to adsorption. In order to simplify the operating steps, in actual production, a certain cycle can be set according to the adsorption capacity of the fixed adsorption bed and the production time, such as a fixed cycle of one week or two weeks, so that the two fixed adsorption beds can be converted from adsorption to desorption, or from desorption to adsorption according to the set cycle.

[0113] The desorption method in the adsorption step is: using heated nitrogen or water vapor to regenerate and desorb the activated carbon in the fixed adsorption bed.

[0114] It should be noted that if heated nitrogen is used to regenerate and desorb the activated carbon in the fixed adsorption bed, then a hot nitrogen desorption device needs to be connected to the adsorption device 7; if heated water vapor is used to regenerate and desorb the activated carbon in the fixed adsorption bed, then the heated water-containing gas discharged from the regeneration unit 22 of the dehumidification equipment 2 can be sent to the fixed adsorption bed to heat the activated carbon in the fixed adsorption bed. This can fully utilize the heat without the need to set up additional equipment, thereby reducing costs and saving resources.

[0115] refer to Fig. 9 The waste gas purification method for lithium battery recycling of the seventh embodiment of the present application specifically comprises the following steps:

[0116] S201 to S207 are the same as the above steps S101 to S107, and will not be repeated here.

[0117] S208, catalytic combustion step: the desorbed exhaust gas enters the catalytic combustor 10 for catalytic thermal decomposition and then is discharged cleanly.

[0118] Through the above catalytic combustion steps, the adsorbent of the fixed adsorption bed can be directly desorbed and enter the catalytic combustor 10 for treatment after being fully absorbed by organic matter, without the need to be transported to the urban green island for centralized desorption. This not only can quickly catalytically decompose the pollutants in the exhaust gas and discharge them cleanly, but also saves the transportation cost of the fixed adsorption bed. In addition, there is no need to replace a new fixed adsorption bed, which also saves the procurement cost of the fixed adsorption bed.

[0119] Embodiment 8

[0120] refer to Fig.10The waste gas purification system for lithium battery recycling provided in Example 8 of the present application includes an alkali washing tower 4, a water washing tower 5, a demisting device 6, a dust removal device 1, a dehumidification device 2, a condensing device 3, an adsorption device 7, a fan 8 and a heating device 9; the inlet of the water washing tower 5 is connected to the outlet of the alkali washing tower 4, and the inlet of the alkali washing tower 4 is used to connect to the lithium battery disassembly and recycling equipment 100, and the outlet of the water washing tower 5 is connected to the inlet of the demisting device 6; the dehumidification device 2 includes a processing unit 21 and a regeneration unit 22, the inlet of the processing unit 21 is connected to the dust removal device 1, the dust removal device 1 is used to connect to the outlet of the demisting device 6, and the outlet of the processing unit 21 is connected to the inlet of the condensing device 3; the inlet of the regeneration unit 22 is connected to the heating device 9, and the heating device 9 is connected to the fan 8; the outlet of the regeneration unit 22 is connected to the water washing tower 5 or the demisting device 6; the outlet of the condensing device 3 is connected to the inlet of the adsorption device 7; the outlet of the adsorption device 7 is used to discharge gas.

[0121] The waste gas purification system for lithium battery recycling provided in Example 8 of the present application is mainly used to treat the waste gas generated during the disassembly and recycling process of lithium batteries. In Example 8 of the present application, the waste gas generated by the lithium battery disassembly and recycling equipment 100 passes through the alkali washing tower 4 to neutralize the acidic substances in the waste gas, passes through the water washing tower 5 to remove the alkali solution and residues in the waste gas, passes through the demister to remove the moisture in the waste gas, passes through the dust removal equipment 1 to remove the powder particles in the waste gas, passes through the dehumidification equipment 2 for drying, passes through the condensation device 3 to condense and precipitate the organic solvent in the waste gas, and finally passes through the adsorption equipment to adsorb the organic matter in the waste gas so as to discharge clean gas. During the entire waste gas purification process, each processing step is processed separately, and different recycling and processing processes can be used to recycle and process different harmful substances in the waste gas, which is not only more efficient, but also more adaptable to the unstable working conditions of the enterprise's waste gas emissions, so as to reasonably optimize the energy consumption of the entire set of equipment.

[0122] In addition, during the entire waste gas treatment process, not only is no additional moisture introduced, but the waste gas is also dried by the dehumidification equipment 2, which solves the problem that the halogen in the waste gas forms a strong acid when it meets water and corrodes the equipment, causing the process to be unable to operate normally; the dew point of the dried waste gas is lower than the cooling temperature of the condensing device 3, and the condensing device 3 is used to recover most of the organic solvent, thereby reducing carbon emissions and realizing a green circular economy.

[0123] The structures of the alkali washing tower 4, water washing tower 5, demisting equipment 6, dust removal equipment 1, dehumidification equipment 2, condensing device 3, adsorption device 7, fan 8 and heating equipment 9 in Example 8 of the present application can refer to the description of Examples 1 to 6 above, and will not be repeated in Example 8 of the present application.

[0124] Embodiment 9

[0125] refer to Fig.11Embodiment 9 of the present application provides a method for purifying waste gas from lithium battery recycling, which is applied to the waste gas purification system for lithium battery recycling in the above embodiment 8, and includes the following steps:

[0126] S301, alkali washing step: the waste gas generated by the lithium battery disassembly and recycling equipment 100 enters the alkali washing tower 4, and is washed with Ca(OH) 2 Or NaOH solution washing to remove acidic substances in the exhaust gas;

[0127] S302, water washing step: the gas after alkali washing enters the water washing tower 5, and the alkali liquid and residue in the gas are removed by water washing;

[0128] S303, defog step: the gas after water washing enters the defogger 6, and the liquid droplets are separated from the gas by centrifugal force and are enriched at the lower part of the defogger 6;

[0129] S304, dust removal step: the demisted gas enters the dust removal device 1 to remove powder particles entrained in the airflow;

[0130] S305, drying step: the gas after dust removal enters the dehumidification device 2, and the processing unit 21 of the dehumidification device 2 adsorbs the moisture in the gas, so that the dew point of the dried gas is lower than -40°C; the clean air heated to 60°C by the heating device 9 enters the regeneration unit 22 of the dehumidification device 2, adsorbs the moisture adsorbed by the processing unit 21 of the dehumidification device 2, and then is sent to the water washing tower 5 or the demisting device 6;

[0131] S306, condensation recovery step: the dried gas enters the condensation device 3, condenses the gas to ≤-20°C, and condenses the organic solvent in the gas;

[0132] S307, adsorption step: the gas after the organic solvent is precipitated enters the adsorption device 7 to adsorb the organic matter in the gas.

[0133] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A waste gas purification system for lithium battery recycling, characterized in that: It comprises dust removal equipment (1), dehumidification equipment (2), condensation equipment (3), alkali washing tower (4), water washing tower (5), demisting equipment (6), adsorption device (7), fan (8) and heating equipment (9); The dehumidification device (2) comprises a processing unit (21) and a regeneration unit (22); the inlet of the processing unit (21) is connected to the dust removal device (1); the dust removal device (1) is used to connect to the lithium battery disassembly and recycling device (100); and the outlet of the processing unit (21) is connected to the inlet of the condensation device (3); The inlet of the regeneration unit (22) is connected to the heating device (9), and the heating device (9) is connected to the fan (8); the outlet of the regeneration unit (22) is connected to the water washing tower (5) or the demisting device (6); The inlet of the alkali washing tower (4) is connected to the outlet of the condensing device (3), and the outlet of the alkali washing tower (4) is connected to the inlet of the water washing tower (5); The inlet of the demisting device (6) is connected to the outlet of the water washing tower (5), and the outlet of the demisting device (6) is connected to the inlet of the adsorption device (7); The outlet of the adsorption device (7) is used to discharge gas.

2. The waste gas purification system for lithium battery recycling according to claim 1, characterized in that: The dehumidification equipment (2) is a molecular sieve dehumidifier; or; The dehumidification equipment (2) comprises a first molecular sieve adsorption tower (201) and a second molecular sieve adsorption tower (202) which are arranged in parallel and are both connected to a switching device (20), wherein the switching device is used to switch the working state of the first molecular sieve adsorption tower (201) and the second molecular sieve adsorption tower (202); wherein the working state comprises a processing unit state and a regeneration unit state.

3. The waste gas purification system for lithium battery recycling according to claim 2 is characterized in that: The outlet of the demisting device (6) is connected to the inlet of the water washing tower (5) so as to transfer the water enriched inside the demisting device (6) to the water washing tower (5).

4. The waste gas purification system for lithium battery recycling according to any one of claims 1 to 3, characterized in that: The dust removal equipment (1) is a bag dust collector or a multi-tube parallel cyclone dust collector.

5. The waste gas purification system for lithium battery recycling according to any one of claims 1 to 3, characterized in that: The condensing device (3) comprises a primary condenser (31), a secondary condenser (32), a condensing unit (33) and a gas-liquid separator (34); The inlet of the primary condenser (31) is connected to the processing unit (21), and the secondary condenser (32) is connected in series with the primary condenser (31) and is connected to the condensing unit (33); The first-stage condenser (31) and the second-stage condenser (32) are both connected to the inlet of the gas-liquid separator (34) for sending the condensate to the gas-liquid separator (34); the outlet of the gas-liquid separator (34) is connected to the second-stage condenser (32) for sending the volatile gas of the gas-liquid separator (34) into the second-stage condenser (32) for deep condensation; the temperature of the exhaust gas passing through the condensation device (3) is ≤-20°C.

6. The waste gas purification system for lithium battery recycling according to any one of claims 1 to 3, characterized in that: The adsorption device (7) comprises two fixed adsorption beds connected in parallel, wherein when one of the fixed adsorption beds is in use, the other fixed adsorption bed is kept activated and regenerated for standby use; The fixed adsorption bed is connected to a desorption device for desorbing and discharging the waste gas from the fixed adsorption bed.

7. The waste gas purification system for lithium battery recycling according to claim 6, characterized in that: Also includes: The catalytic burner (10) is connected to the outlet of the fixed adsorption bed and is used for catalytically decomposing the desorbed exhaust gas and then discharging it cleanly.

8. A method for purifying waste gas from lithium battery recycling, applied to the waste gas purification system for lithium battery recycling as described in any one of claims 1 to 7, characterized in that: The following steps are involved: Dust removal step: the waste gas generated by the lithium battery disassembly and recycling equipment (100) enters the dust removal equipment (1) to remove the powder particles entrained in the air flow; Drying step: the gas after dust removal enters the dehumidification device (2), and the processing unit (21) of the dehumidification device (2) absorbs moisture in the gas, so that the dew point of the dried gas is lower than -40°C; the clean air heated to 60°C by the heating device (9) enters the regeneration unit (22) of the dehumidification device (2), absorbs the moisture absorbed by the processing unit (21) of the dehumidification device (2), and is then sent to the water scrubber (5) or the demisting device (6); Condensation recovery step: the dried gas enters the condensation device (3), condenses the gas to ≤-20°C, and condenses the organic solvent in the gas; Alkali washing step: the gas after the organic solvent is precipitated enters the alkali washing tower (4) and is washed with Ca(OH)2 or NaOH solution to remove the acidic substances in the gas; Water washing step: the gas after alkali washing enters the water washing tower (5), and the alkali liquid and residue in the gas are removed by water washing; Demisting step: the gas after water washing enters the demisting device (6), and the liquid droplets are separated from the gas by centrifugal force and are enriched in the lower part of the demisting device (6); Adsorption step: the demisted gas enters the adsorption device (7) to adsorb the organic matter in the gas.

9. The method for purifying waste gas from lithium battery recycling according to claim 8, characterized in that: The demisting step is specifically as follows: the gas after water washing enters the demisting device (6), the liquid droplets are separated from the gas by centrifugal force, and are enriched at the lower part of the demisting device (6); the enriched water is sent to the water washing tower (5).

10. The method for purifying waste gas from lithium battery recycling according to claim 8, characterized in that: The adsorption step is specifically as follows: the demisted gas enters two fixed adsorption beds of the adsorption device (7); according to a preset time period, the two fixed adsorption beds alternately adsorb and desorb organic matter in the gas; after reaching the emission standard, the gas is discharged through the outlet of the adsorption device (7).

11. The method for purifying waste gas from lithium battery recycling according to claim 10, characterized in that: The desorption method in the adsorption step is: using heated nitrogen or water vapor to regenerate and desorb the activated carbon in the fixed adsorption bed.

12. The method for purifying waste gas from lithium battery recycling according to claim 10 or 11, characterized in that: The following steps are also included: Catalytic combustion step: the desorbed waste gas enters the catalytic burner (10) for catalytic thermal decomposition and then is discharged cleanly.

13. A waste gas purification system for lithium battery recycling, characterized in that: It comprises an alkali washing tower (4), a water washing tower (5), a demisting device (6), a dust removal device (1), a dehumidification device (2), a condensing device (3), an adsorption device (7), a fan (8) and a heating device (9); The inlet of the water washing tower (5) is connected to the outlet of the alkali washing tower (4), the inlet of the alkali washing tower (4) is used to connect to the lithium battery disassembly and recycling equipment (100), and the outlet of the water washing tower (5) is connected to the inlet of the demisting equipment (6); The dehumidification device (2) comprises a processing unit (21) and a regeneration unit (22); the inlet of the processing unit (21) is connected to the dust removal device (1); the dust removal device (1) is used to be connected to the outlet of the demisting device (6); and the outlet of the processing unit (21) is connected to the inlet of the condensing device (3); The inlet of the regeneration unit (22) is connected to the heating device (9), and the heating device (9) is connected to the fan (8); the outlet of the regeneration unit (22) is connected to the water washing tower (5) or the demisting device (6); The outlet of the condensation device (3) is connected to the inlet of the adsorption device (7); The outlet of the adsorption device (7) is used to discharge gas.

14. A method for purifying waste gas from lithium battery recycling, applied to the waste gas purification system for lithium battery recycling as claimed in claim 13, characterized in that: The following steps are involved: Alkali washing step: the waste gas generated by the lithium battery disassembly and recycling equipment (100) enters the alkaline washing tower (4) and is washed with Ca(OH)2 or NaOH solution to remove acidic substances in the waste gas; Water washing step: the gas after alkali washing enters the water washing tower (5), and the alkali liquid and residue in the gas are removed by water washing; Demisting step: the gas after water washing enters the demisting device (6), and the liquid droplets are separated from the gas by centrifugal force and are enriched in the lower part of the demisting device (6); Dust removal step: the demisted gas enters the dust removal equipment (1) to remove the powder particles entrained in the air flow; Drying step: the gas after dust removal enters the dehumidification device (2), and the processing unit (21) of the dehumidification device (2) absorbs moisture in the gas, so that the dew point of the dried gas is lower than -40°C; the clean air heated to 60°C by the heating device (9) enters the regeneration unit (22) of the dehumidification device (2), absorbs the moisture absorbed by the processing unit (21) of the dehumidification device (2), and is then sent to the water scrubber (5) or the demisting device (6); Condensation recovery step: the dried gas enters the condensation device (3), condenses the gas to ≤-20°C, and condenses the organic solvent in the gas; Adsorption step: The gas after the organic solvent is precipitated enters the adsorption device (7) to adsorb the organic matter in the gas.

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