Recovery system and method for electrolyte solvent in waste gas generated during disassembly of waste lithium battery

Abstract

The invention discloses a system and a method for recycling an electrolyte solvent in waste gas generated during disassembly of a waste lithium battery, the recycling system comprises multiple stages of adsorption gas paths, the adsorption gas paths are arranged in series, the waste gas is introduced into the inlet ends of the adsorption gas paths, and clean materials subjected to adsorption treatment are discharged from the outlet ends of the adsorption gas paths; an adsorber is arranged on each stage of adsorption gas path, and valves are mounted on an inlet pipeline and an outlet pipeline of each adsorber; each adsorber is communicated with the circulating desorption gas circuit through a desorption pipeline, and in the operation process of the system, one of the adsorbers performs desorption regeneration operation, and the other adsorbers perform adsorption purification operation. And the energy reutilization rate is improved.

Description

Technical Field

[0001] This invention relates to the field of chemical equipment technology, specifically to a system and method for recovering electrolyte solvent from waste gas from the dismantling of waste lithium batteries. Background Technology

[0002] With the booming development of the new energy industry, lithium batteries are widely used in various sectors. The rapid development of new energy vehicles and energy storage technologies has led to a rapid increase in the demand and consumption of lithium batteries nationwide and even worldwide. However, the long-term and widespread use of lithium batteries inevitably results in the generation of a large number of waste lithium batteries, while also increasing the pressure on natural resources and environmental protection.

[0003] Currently, the recycling industry for spent lithium batteries is developing rapidly, with continuous upgrades in its technology. Spent lithium batteries contain various valuable metallic materials such as lithium, cobalt, nickel, and copper, as well as essential electrolyte organic materials. Recycled cobalt and lithium can be reused to manufacture new lithium batteries, forming a resource cycle and helping to alleviate resource shortages and reduce battery production costs. Efficiently recycling lithium battery resources not only reduces the demand for primary mineral resources and mitigates environmental damage, but also generates considerable economic benefits and promotes sustainable development.

[0004] Currently, the recycling and reuse of spent lithium batteries mainly focuses on the metal materials. However, the large amount of organic carbonate materials contained in lithium batteries evaporates during crushing and other processes, entering the atmosphere and generating organic waste gas emissions, resulting in ineffective waste. To treat these gases harmlessly and protect the environment, the industry commonly uses incineration and other destruction technologies to achieve emission standards. Summary of the Invention

[0005] Therefore, embodiments of the present invention provide a system and method for recovering electrolyte solvent from waste gas from the dismantling of waste lithium batteries, in order to solve at least one of the above-mentioned technical problems.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] This invention provides a system for recovering electrolyte solvent from waste gas from the dismantling of waste lithium batteries, comprising:

[0008] The system comprises a multi-stage adsorption gas path, with each stage of the adsorption gas path connected in series. Waste gas is introduced into the inlet of each stage of the adsorption gas path, and the clean material after adsorption treatment is discharged from the outlet of each stage of the adsorption gas path. Each stage of the adsorption gas path is equipped with an adsorber, and valves are installed on the inlet and outlet pipes of each adsorber.

[0009] The circulating desorption gas path is connected to each of the adsorbers through a desorption pipeline. During system operation, one of the adsorbers performs desorption and regeneration operations, while the other adsorbers perform adsorption and purification operations.

[0010] In some embodiments, the circulating desorption gas path includes a heater, a heat exchanger, a condenser, and a desorption fan that are connected to the adsorber via a desorption pipeline.

[0011] In some embodiments, the end of the circulating desorption gas path is connected to a recovery storage tank.

[0012] In some embodiments, the recycling system further includes:

[0013] The purifier is connected to the circulating desorption gas circuit via a pipeline, and a valve is installed on the connection pipeline.

[0014] In some embodiments, the adsorber is at least three.

[0015] In some embodiments, the oxygen content in the circulating desorption gas path is less than or equal to 0.1%.

[0016] In some embodiments, the nitrogen temperature in the adsorption gas path is 250-300°C.

[0017] The present invention also provides a recycling method based on the recycling system described above, the method comprising:

[0018] Under adsorption conditions, open valves 1 and 2 of the primary adsorber, open valves 3 and 4 of the secondary adsorber, and close the other valves of the primary and secondary adsorbers. The waste gas passes through the primary and secondary adsorbers in sequence, and the clean gas after adsorption and purification is discharged from the recovery system, thus ending the adsorption operation.

[0019] Under replacement conditions, the tertiary adsorber acts as the desorber. Open valves 2 and 6 of the desorber, valves C and D of the purifier, and valves A and B of the heat exchanger. Close other valves on the circulating desorption gas line. Open nitrogen valve K to replace all air-passing devices in the circulating desorption gas line with high-purity nitrogen. The replaced gas is discharged into the secondary adsorption pipeline through valve 2 of the desorber. Close nitrogen valve K and valve 2 of the desorber to end the replacement operation.

[0020] During desorption, open valves 5 and 6 of the desorber, simultaneously open valves E and F of the purifier, open valve A of the heat exchanger, and close other valves on the circulating desorption gas path; turn on the desorption fan and heater, and adjust the heater power to bring the temperature of the circulating gas to the preset desorption inlet temperature of the desorber; after the circulating hot nitrogen enters the desorber and purifier, it passes through the heat exchanger, enters the condenser, and then passes through valve H, the desorption fan, the heat exchanger, and the heater in sequence, returning the hot air to the desorber and purifier for continuous circulating desorption and regeneration; the desorber and purifier are simultaneously desorbed by the hot air circulation, and the desorbed organic matter is condensed in the condenser and recycled into the storage tank, ending the desorption operation;

[0021] Under purification conditions, based on the valve positions under desorption conditions, open valves C and D of the purifier, while simultaneously closing valves E and F, and closing valve H. The circulating gas path is: desorber - heat exchanger - condenser - purifier - desorption fan - heat exchanger - heater - desorber. After the purifier is cooled down, it begins to adsorb and purify the residual organic matter in the circulating gas until the residual organic matter in the circulating gas is completely adsorbed and transferred into the purifier, thus ending the purification operation.

[0022] During the cooling operation, the heater stops heating, valve B of the heat exchanger is opened, and valve A of the heat exchanger is closed. The heat in the desorber is carried out by the circulating gas and absorbed by the condenser until the temperature of all components and adsorbent materials in the desorption system drops below the preset temperature. Then, the desorption fan is turned off, and valves 5 and 6 of the desorber are closed to end the cooling operation.

[0023] In some embodiments, the method further includes:

[0024] During the desorption process, instruments are used to monitor the oxygen content of the gas inside the pipeline.

[0025] In some embodiments, under adsorption conditions, the adsorption time is greater than or equal to 12 hours.

[0026] The present invention provides a system and method for recovering electrolyte solvents from waste lithium battery dismantling exhaust gas. By establishing an efficient method for high-concentration recovery of electrolyte solvents, it significantly reduces the refining cost of electrolyte solvents. At the same time, it supplements the liquid-phase material processing technology in the field of waste lithium battery dismantling and recycling, reduces the recovery efficiency of waste lithium battery electrolyte solvents, and improves the energy reuse rate. Attached Figure Description

[0027] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0028] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0029] Figure 1 This is a schematic diagram of the recycling system provided by the present invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1-Adsorber, 2-Purifier, 3-Heater, 4-Heat Exchanger, 5-Condenser, 6-Desorption Fan, 7-Recovery Storage Tank;

[0032] ①-⑥ are valves of the adsorber, and AF is a valve in the circulating desorption gas path. Detailed Implementation

[0033] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In one specific embodiment, the recycling system provided by the present invention is used to recover electrolyte solvents from waste lithium battery dismantling exhaust gases, such as... Figure 1 As shown, the recovery system includes a multi-stage adsorption gas path and a circulating desorption gas path. The adsorption gas paths at each stage are connected in series. Waste gas is introduced into the inlet of each stage of the adsorption gas path, and the cleaned material after adsorption treatment is discharged from the outlet of each stage. Each stage of the adsorption gas path is equipped with an adsorber 1, and valves are installed on the inlet and outlet pipes of each adsorber 1. Each adsorber 1 is connected to the circulating desorption gas path through a desorption pipe. During system operation, one of the adsorbers 1 performs desorption and regeneration operations, while the remaining adsorbers 1 perform adsorption and purification operations.

[0035] The adsorber 1 consists of at least three units, with two adsorbers 1 connected in series to form a two-stage adsorption mode. In other words, the recovery system uses three or more adsorbers connected in series, with each stage of the adsorber 1 having the same structure. All adsorbers 1 are connected via pipes and valves to form a multi-stage adsorption gas path, achieving a two-stage or higher adsorption mode. It can be understood that with three adsorbers, two adsorbers form a two-stage adsorption system in series; with four adsorbers, three adsorbers form a three-stage adsorption system in series; one adsorber is a backup for desorption.

[0036] It can withstand long-term exhaust gas purification and protection, while controlling the adsorption time. In the pre-adsorber, the electrolyte solvent is enriched to the maximum extent and the adsorbed water is removed. During the desorption process, the electrolyte solvent with very low water content can be recovered.

[0037] Furthermore, the circulating desorption gas path includes a heater 3, a heat exchanger 4, a condenser 5, a desorption fan 6, and a recovery storage tank 7, all connected to the adsorber 1 via desorption pipelines. It can be understood that the combination of the circulating desorption gas path and the multi-stage adsorption gas path forms an ultra-low oxygen content high-temperature nitrogen desorption and regeneration system for recovering the electrolyte solvent in the liquid phase. All adsorbers 1 are connected to the heater 3, heat exchanger 4, condenser 5, and desorption fan 6 via desorption pipelines, forming a closed circulating desorption gas path. During operation, one adsorber in the multi-stage adsorber 1 undergoes desorption and regeneration, while the remaining adsorbers are used for adsorption operations.

[0038] The oxygen content in the circulating desorption gas path is less than or equal to 0.1%. In the low-oxygen, high-temperature nitrogen desorption and regeneration process, the oxygen content in the circulating desorption gas path does not exceed 0.1% during regeneration, the nitrogen temperature in the adsorption gas path is 250-300℃, and the safe adsorption protection time is not less than 12 hours. Thus, the adsorber 1 uses high-temperature nitrogen with an oxygen content of less than 0.1% and a temperature range of 250-300℃ to continuously purge and desorb organic matter from the adsorber in a closed-loop pipeline. Further liquefaction and condensation are completed in the condensation system to obtain a high-concentration liquid electrolyte solvent that is easy to store. Specifically, in conventional nitrogen desorption and regeneration, the oxygen content is controlled within the range of 1-5%. This range is mainly considered for operational safety, i.e., to prevent the combustion or explosion of organic matter in the gas path. During prolonged desorption, oxygen can adversely affect the recovered organic matter and also affect the microporous structure of the adsorbent to some extent. The 0.1% data used in this invention, in addition to being safer, better protects the properties of the recovered organic matter, better protects the microporous structure of the adsorbent, and improves the service life of the adsorbent. Meanwhile, the boiling point range of volatile electrolyte components is generally below 250℃. The higher the desorption temperature, the more heat is supplied per unit time, enabling faster desorption and regeneration. Furthermore, a desorption temperature above 250℃ is necessary to ensure the complete removal of adsorbed electrolyte components.

[0039] Furthermore, the recovery system also includes a purifier 2, which is connected to the circulating desorption gas path via a pipeline, and a valve is installed on the connecting pipeline. The purifier 2 is connected to the desorption gas path via a pipeline and switches the valve to purify and remove residual organic matter in the circulating desorption gas path after the desorption process is completed. The aforementioned recovery storage tank is connected to a condenser 5 via a pipeline to receive the electrolyte solvent recovery product generated by the condensation of the circulating desorption gas path.

[0040] To facilitate understanding, the overall structure of the recycling system provided by this invention will be briefly described below using a specific application scenario as an example.

[0041] The recycling system provided by this invention is used in the dismantling process of waste lithium batteries. Electrolyte solvents generated due to exposure and heating evaporate into the air. This system purifies and recycles this waste gas containing gaseous electrolyte solvent components. Please continue to refer to [reference needed]. Figure 1 The recovery system includes three or more adsors 1, as well as a purifier 2, a heater 3, a heat exchanger 4, a condenser 5, a desorption fan 6, and a recovery storage tank 7. The recovery system includes valves 1-6: valve 1 is the primary adsorption inlet, connected to the primary intake line; valve 2 is the primary adsorption exhaust, connected to the secondary intake line; valve 3 is the secondary adsorption inlet, connected to the secondary intake line; valve 4 is the secondary adsorption exhaust, connected to the final discharge line; valve 5 is the desorption inlet valve, connected to the desorption inlet line; and valve 6 is the desorption exhaust valve, connected to the desorption outlet line.

[0042] To facilitate the description of pipeline connectivity, Figure 1 The three adsorbers, from left to right, are defined as the first-stage adsorber, the second-stage adsorber, and the third-stage adsorber, respectively. The air inlet of each adsorber is connected to the exhaust gas inlet through an air inlet pipe. Each air inlet pipe is equipped with valve No. 1. When valve No. 1 is open, the exhaust gas can enter the adsorber. The air outlet of each adsorber is connected to the clean gas discharge end through an air outlet pipe. Each air outlet pipe is equipped with valve No. 4. When valve No. 4 is open, the clean gas obtained after purification treatment can be discharged from the adsorber.

[0043] All adsorbers 1 are connected by pipes and valves to form a multi-stage adsorption gas path. Simultaneously, all adsorbers 1, heaters 3, heat exchangers 4, condensers 5, and desorption fans 6 are connected by desorption pipes to form a closed-loop desorption gas path. During operation, one adsorber 1 undergoes desorption and regeneration, while the remaining adsorbers 1 work together to complete the multi-stage adsorption and purification process.

[0044] Adsorber 1 is desorbed and regenerated using high-temperature nitrogen with ultra-low oxygen content.

[0045] Purifier 2 is connected to the desorption gas path via a pipeline and a switching valve. After the desorption process is completed, it purifies and removes the residual organic matter in the circulating desorption gas path.

[0046] The recovery storage tank 7 is connected to the condenser 5 by a pipeline to receive the electrolyte solvent recovery product generated by the condensation of the circulating desorption gas path.

[0047] The recycling system provided by this invention, by setting up a multi-stage continuous adsorption circuit and a desorption circulation circuit, can effectively increase the concentration of the recovered electrolyte solvent and significantly reduce the water content. It can efficiently purify the organic waste gas generated during the dismantling of waste lithium batteries and recover high-concentration, low-water-content electrolyte, meeting environmental protection requirements while reducing the difficulty and cost of electrolyte solvent recycling and reuse.

[0048] Based on the recycling system described above, the present invention also provides a recycling method, the method comprising:

[0049] Under adsorption conditions, open valves 1 and 2 of the primary adsorber, open valves 3 and 4 of the secondary adsorber, and close the other valves of the primary and secondary adsorbers. The waste gas passes through the primary and secondary adsorbers in sequence, and the clean gas after adsorption and purification is discharged from the recovery system, thus ending the adsorption operation. Under adsorption conditions, the adsorption time is greater than or equal to 12 hours.

[0050] Under replacement conditions, the tertiary adsorber acts as the desorber. Open valves 2 and 6 of the desorber, valves C and D of the purifier, and valves A and B of the heat exchanger. Close other valves on the circulating desorption gas line. Open nitrogen valve K to replace all air-passing devices in the circulating desorption gas line with high-purity nitrogen. The replaced gas is discharged into the secondary adsorption pipeline through valve 2 of the desorber. Close nitrogen valve K and valve 2 of the desorber to end the replacement operation.

[0051] During desorption, open valves 5 and 6 of the desorber, simultaneously open valves E and F of the purifier, open valve A of the heat exchanger, and close other valves on the circulating desorption gas line; turn on the desorption fan and heater, and adjust the heater power to bring the temperature of the circulating gas to the preset desorption inlet temperature of the desorber; after the circulating hot nitrogen enters the desorber and purifier, it passes through the heat exchanger, enters the condenser, and then passes through valve H, the desorption fan, the heat exchanger, and the heater in sequence, returning the hot air to the desorber and purifier for continuous circulating desorption and regeneration; the desorber and purifier are simultaneously desorbed by the hot air circulation, and the desorbed organic matter is condensed in the condenser and recovered into the storage tank, ending the desorption operation; during the desorption process, the oxygen content of the gas inside the pipeline is monitored using instruments.

[0052] Under purification conditions, based on the valve positions under desorption conditions, open valves C and D of the purifier, while simultaneously closing valves E and F, and closing valve H. The circulating gas path is: desorber - heat exchanger - condenser - purifier - desorption fan - heat exchanger - heater - desorber. After the purifier is cooled down, it begins to adsorb and purify the residual organic matter in the circulating gas until the residual organic matter in the circulating gas is completely adsorbed and transferred into the purifier, thus ending the purification operation.

[0053] During the cooling operation, the heater stops heating, valve B of the heat exchanger is opened, and valve A of the heat exchanger is closed. The heat in the desorber is carried out by the circulating gas and absorbed by the condenser until the temperature of all components and adsorbent materials in the desorption system drops below the preset temperature. Then, the desorption fan is turned off, and valves 5 and 6 of the desorber are closed to end the cooling operation.

[0054] Among them, valve A is the direct-acting valve of the heat exchanger, and valve B is the bypass shielded valve of the heat exchanger. One is open and the other is closed. When valve A is open, heat is recovered; when valve B is open, heat is not recovered. Valves C and D are the adsorption inlet and outlet valves of the purifier; valves E and F are the desorption inlet and outlet valves of the purifier.

[0055] Using the above method, the recovered electrolyte solvent has a water content of less than 6%. The single-stage adsorption method commonly used for electrolyte waste gas cannot effectively separate the electrolyte and water through mass transfer, resulting in a high water content in the recovered material, typically between 10-30%. This invention, however, utilizes a multi-stage adsorption process to specifically desorb and recover the low-water-content adsorption section after efficient mass transfer, effectively solving the problem of high water content in the recovered electrolyte.

[0056] Thus, the recycling method provided by this invention establishes a highly efficient method for high-concentration recovery of electrolyte solvents, resulting in electrolyte solvents with very low water content, which significantly reduces the refining cost of electrolyte solvents.

[0057] In the above specific embodiments, the system and method for recovering electrolyte solvents in waste lithium battery dismantling exhaust gas provided by the present invention significantly reduces the refining cost of electrolyte solvents by establishing an efficient high-concentration recovery method for electrolyte solvents. At the same time, it supplements the liquid phase material processing technology in the field of waste lithium battery dismantling and recycling, reduces the recovery efficiency of waste lithium battery electrolyte solvents, and improves the energy reuse rate.

[0058] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of the present invention should be included within the scope of protection of the present invention.

Claims

1. A system for recovering electrolyte solvent from waste gas from the dismantling of waste lithium batteries, characterized in that, include: The system comprises a multi-stage adsorption gas path, with each stage of the adsorption gas path connected in series. Waste gas is introduced into the inlet of each stage of the adsorption gas path, and the clean material after adsorption treatment is discharged from the outlet of each stage of the adsorption gas path. Each stage of the adsorption gas path is equipped with an adsorber, and valves are installed on the inlet and outlet pipes of each adsorber. The circulating desorption gas path is connected to each of the adsorbers through a desorption pipeline. During system operation, one of the adsorbers performs desorption and regeneration operations, while the other adsorbers perform adsorption and purification operations.

2. The recycling system according to claim 1, characterized in that, The circulating desorption gas path includes a heater, a heat exchanger, a condenser, and a desorption fan that are connected to the adsorber via a desorption pipeline.

3. The recycling system according to claim 2, characterized in that, The end of the circulating desorption gas path is connected to a recovery storage tank.

4. The recycling system according to claim 2, characterized in that, Also includes: The purifier is connected to the circulating desorption gas circuit via a pipeline, and a valve is installed on the connection pipeline.

5. The recycling system according to any one of claims 1-4, characterized in that, The number of adsorbers is at least three.

6. The recycling system according to any one of claims 1-4, characterized in that, The oxygen content in the circulating desorption gas path is less than or equal to 0.1%.

7. The recycling system according to any one of claims 1-4, characterized in that, The nitrogen temperature in the adsorption gas path is 250-300℃.

8. A recycling method, based on the recycling system as described in any one of claims 1-7, characterized in that, The method includes: Under adsorption conditions, open valves 1 and 2 of the primary adsorber, open valves 3 and 4 of the secondary adsorber, and close the other valves of the primary and secondary adsorbers. The waste gas passes through the primary and secondary adsorbers in sequence, and the clean gas after adsorption and purification is discharged from the recovery system, thus ending the adsorption operation. Under replacement conditions, the tertiary adsorber acts as the desorber. Open valves 2 and 6 of the desorber, valves C and D of the purifier, and valves A and B of the heat exchanger. Close other valves on the circulating desorption gas line. Open nitrogen valve K to replace all air-passing devices in the circulating desorption gas line with high-purity nitrogen. The replaced gas is discharged into the secondary adsorption pipeline through valve 2 of the desorber. Close nitrogen valve K and valve 2 of the desorber to end the replacement operation. During desorption, open valves 5 and 6 of the desorber, simultaneously open valves E and F of the purifier, open valve A of the heat exchanger, and close other valves on the circulating desorption gas path; turn on the desorption fan and heater, and adjust the heater power to bring the temperature of the circulating gas to the preset desorption inlet temperature of the desorber; after the circulating hot nitrogen enters the desorber and purifier, it passes through the heat exchanger, enters the condenser, and then passes through valve H, the desorption fan, the heat exchanger, and the heater in sequence, returning the hot air to the desorber and purifier for continuous circulating desorption and regeneration; the desorber and purifier are simultaneously desorbed by the hot air circulation, and the desorbed organic matter is condensed in the condenser and recycled into the storage tank, ending the desorption operation; Under purification conditions, based on the valve positions under desorption conditions, open valves C and D of the purifier, while simultaneously closing valves E and F, and closing valve H. The circulating gas path is: desorber - heat exchanger - condenser - purifier - desorption fan - heat exchanger - heater - desorber. After the purifier is cooled down, it begins to adsorb and purify the residual organic matter in the circulating gas until the residual organic matter in the circulating gas is completely adsorbed and transferred into the purifier, thus ending the purification operation. During the cooling operation, the heater stops heating, valve B of the heat exchanger is opened, and valve A of the heat exchanger is closed. The heat in the desorber is carried out by the circulating gas and absorbed by the condenser until the temperature of all components and adsorbent materials in the desorption system drops below the preset temperature. Then, the desorption fan is turned off, and valves 5 and 6 of the desorber are closed to end the cooling operation.

9. The recycling method according to claim 8, characterized in that, The method further includes: During the desorption process, instruments are used to monitor the oxygen content of the gas inside the pipeline.

10. The recycling method according to claim 8, characterized in that, Under adsorption conditions, the adsorption time is greater than or equal to 12 hours.

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