A method and system for recovering VOCs in waste power battery electrolyte based on directional regulation of MOF material IAST structure

Abstract

This invention relates to a method and system for recovering VOCs from the electrolyte of spent power batteries based on the directional control of the IAST structure of MOF materials. The method involves dismantling and crushing battery cells, extracting volatile gases from the dismantling and crushing stage to form a VOCs-containing gas stream. The method includes real-time monitoring of the components and concentrations in the VOCs-containing gas stream, and performing IAST selectivity calculations on each target component based on the monitoring results. The method then selects or directionally controls the MOF material structure based on the IAST selectivity calculation results. The selected or directionally controlled MOF material is used for multi-stage adsorption of VOCs. The saturated MOF material is heated and desorbed at a temperature below the high-temperature regeneration temperature, and then cooled to the adsorption temperature for regeneration. The desorbed gas is condensed to recover the electrolyte. The beneficial effects include: improved adsorption efficiency and selectivity of toxic and harmful VOCs in the electrolyte; and low-temperature desorption, avoiding MOF material framework collapse and electrolyte thermal decomposition.

Description

Technical Field

[0001] This invention relates to the field of waste power battery recycling technology, specifically to a method and system for recovering VOCs from the electrolyte of waste power batteries based on the directional control of the IAST structure of MOF materials. Background Technology

[0002] During the dismantling of spent lithium-ion batteries, a large amount of toxic and harmful volatile organic compounds (VOCs) are released from the electrolyte inside the cells. These mainly include: carbonate organic solvents (EC, DMC, DEC, FEC, etc.), lithium salt decomposition products (HF, PF5, and other highly corrosive and toxic gases), small amounts of additives, and fluorides. These substances are characterized by high toxicity, high volatility, flammability, explosiveness, and strong corrosiveness, posing a significant environmental and safety challenge to the spent lithium-ion battery recycling industry. The shortcomings of traditional technologies are as follows: Condensation method: low recovery rate for low-boiling-point and low-concentration VOCs, high penetration rate, difficult to meet emission standards, and cannot achieve targeted separation of toxic components; Traditional adsorbents such as activated carbon and molecular sieves have poor selectivity for mixed VOCs in IAST and are prone to competitive adsorption; they have low adsorption capacity and slow adsorption rate; they have high regeneration temperature (usually >200℃), which can easily cause adsorbent deactivation and electrolyte thermal decomposition; they have few cycles, high operating costs, and are difficult to apply industrially. Electrolyte recovery technologies include multi-focus liquid phase extraction, distillation, and crystallization, which almost do not involve the targeted recovery of gaseous VOCs from the dismantling and crushing process. Existing technologies related to MOF materials are mostly used for the separation of CO2, CH4, and conventional VOCs (e.g., low-carbon hydrocarbon adsorption and separation); they are rarely used in VOCs systems of power battery electrolytes, especially not in the adsorption of mixed systems of HF, PF5, and carbonate components. There are no technical solutions based on IAST theory to directionally control the MOF structure to achieve selective adsorption of toxic components in the electrolyte; there are no complete process and equipment systems coupled with the physical dismantling section of power batteries, which are different from the waste gas treatment processes in the lithium battery production process (e.g., condensation + activated carbon adsorption, rotary wheel concentration + catalytic combustion). Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method and system for VOCs recovery from the electrolyte of waste power batteries based on the directional control of the IAST structure of MOF materials, so as to solve the problems of low VOCs recovery rate, poor selectivity and difficulty in directional capture of toxic components in the electrolyte during the dismantling and crushing of battery cells, as well as the problems of high regeneration temperature, easy deactivation and short cycle life of traditional adsorbents.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A method for recovering VOCs from the electrolyte of spent power batteries based on the directional control of the IAST structure of MOF materials includes the following steps: S1. Disassemble the broken battery cells under closed conditions and extract the volatile gases in the disassembly and crushing section to form a mixed gas flow containing electrolyte and VOCs. S2. Real-time detection of each component and concentration in the VOCs mixed gas flow containing electrolyte, and IAST selectivity calculation of each target component based on the detection results; S3. Screening or directional control of MOF material structure based on IAST selective calculation results; S4. The selected or directionally controlled MOF material is used to adsorb VOCs in multiple stages. The saturated MOF material is heated and desorbed at a temperature lower than the high temperature regeneration temperature. After desorption is completed, it is cooled to the adsorption temperature to regenerate it. S5. Condense the desorbed gas to recover the electrolyte.

[0005] Based on the above technical solution, the present invention can be further improved as follows.

[0006] Furthermore, in S1, when dismantling the broken battery cell under sealed conditions, an inert protective gas is introduced to create a slightly negative pressure environment. The inert protective gas is N2 or Ar.

[0007] Furthermore, in S2, GC-MS or online spectroscopy is used to detect the VOCs components and concentrations in the mixed gas flow in real time.

[0008] Furthermore, the IAST selectivity calculation for each target component includes: the adsorption amount and adsorption rate of each target component, and the IAST selectivity coefficient of different MOF materials for toxic components.

[0009] Furthermore, the control methods in S3 include, but are not limited to: pore size control, ligand functional group modification, defect engineering control, and metal node replacement / ligand exchange.

[0010] Furthermore, pore size control aims to match the pore size of MOF materials with the molecular dynamics diameters of HF, PF5, and FEC; ligand functional group modification introduces polar sites that specifically adsorb acidic toxic gases, including -NH2, -OH, and -F; and defect engineering control increases the specific surface area and adsorption site density of MOF materials.

[0011] Furthermore, the multi-stage adsorption of VOCs using MOF materials in S4 specifically involves a two-stage fixed bed adsorption of VOCs. The first-stage fixed bed uses high-capacity MOF materials to adsorb carbonate organic components, while the second-stage fixed bed uses high IAST-selective MOF materials to directionally adsorb fluorinated carbonates (FEC) and decompose acidic gases (HF, PF5) with lithium salts.

[0012] Furthermore, the heating and desorption of saturated MOF materials in S4 at a temperature below the high-temperature regeneration temperature specifically involves: Saturated MOF materials were subjected to programmed heating desorption at 80℃~150℃ and purged with inert gas.

[0013] Furthermore, the saturated high-capacity MOF material in the first-stage fixed bed was subjected to programmed temperature desorption at 80℃~150℃, and purged with inert gas; and the highly IAST-selective MOF material in the second-stage fixed bed was subjected to programmed temperature desorption at 80℃~150℃, and purged with inert gas.

[0014] Based on the above technical solution, the present invention also provides a VOCs recovery system for waste power battery electrolyte based on the directional control of the IAST structure of MOF materials, for performing the above-mentioned VOCs recovery method for waste power battery electrolyte based on the directional control of the IAST structure of MOF materials, comprising: a closed dismantling and crushing unit, a VOCs pretreatment unit, an online detection and IAST calculation unit, a multi-stage MOF adsorption unit, a low-temperature desorption unit, and a condensation and recovery unit. The VOCs mixed gas flow containing the electrolyte in the closed dismantling and crushing unit is fed into the VOCs pretreatment unit, and the pretreated VOCs in the VOCs pretreatment unit are fed into the multi-stage MOF adsorption unit. In the MOF adsorption unit, the online detection and IAST calculation unit is used to detect the components and concentrations of each pretreated VOCs fed into the multi-stage MOF adsorption unit from the VOCs pretreatment unit in real time, and to perform IAST selectivity calculations for each target component; the low-temperature desorption unit is used to perform low-temperature heating desorption of each stage of saturated MOF material in the multi-stage MOF adsorption unit; the desorbed gas in the multi-stage MOF adsorption unit is sent to the condensation and recovery unit; the closed disassembly and crushing unit, VOCs pretreatment unit, online detection and IAST calculation unit, multi-stage MOF adsorption unit, low-temperature desorption unit and condensation and recovery unit are electrically connected to the control unit.

[0015] Furthermore, the sealed dismantling and crushing unit includes: an explosion-proof sealed dismantling and crushing machine, the air inlet of which is connected to the air outlet of the inert gas supply module, and the air outlet of which is connected to the air inlet of the negative pressure extraction module; the VOCs pretreatment unit includes: a dust collector, a preheater, and a flow stabilizer connected in sequence, the air inlet of which is connected to the air outlet of the negative pressure extraction module; the online detection and IAST calculation unit includes: a GC-MS / online detector, which is electrically connected to the IAST calculation module; The multi-stage MOF adsorption unit includes a primary MOF adsorption tower and a secondary MOF adsorption tower. The inlet of the primary MOF adsorption tower is connected to the outlet of the flow stabilizer. The primary MOF adsorption tower is filled with high-capacity MOF material for adsorbing carbonate organic components. VOCs that are not fully adsorbed in the primary MOF adsorption tower are sent to the secondary MOF adsorption tower. The secondary MOF adsorption tower is filled with high IAST selective MOF material for adsorbing HF, PF5, and FEC. The low-temperature desorption unit includes a programmed temperature rise heating module and an inert gas purging unit. The programmed temperature rise heating module is used to perform low-temperature heating desorption of saturated high-capacity MOF material in the primary MOF adsorption tower at 80℃~150℃; the programmed temperature rise heating module is used to perform low-temperature heating desorption of saturated high IAST selective MOF material in the secondary MOF adsorption tower at 80℃~150℃; the inert gas purging unit is used to purge the primary MOF adsorption tower and the secondary MOF adsorption tower with inert gas respectively. The condensation recovery unit includes a condenser and an electrolyte recovery storage tank. The desorbed gas in the primary MOF adsorption tower and the secondary MOF adsorption tower is sent to the condenser, and the condensate in the condenser is sent to the electrolyte recovery storage tank. The control unit includes a PLC controller and a human-machine interface module and a data storage module that are electrically connected to the PLC controller. The PLC controller is electrically connected to the explosion-proof sealed dismantling and crushing machine, the VOCs pretreatment unit, the GC-MS / online detector, the IAST calculation module, the first-stage MOF adsorption tower, the second-stage MOF adsorption tower, the programmed temperature rise heating module, the inert gas purging unit, and the condenser.

[0016] The beneficial effects of this invention are: Significantly enhanced selectivity: Based on IAST calculations to screen or directionally control the structure of MOF materials, high selectivity, high capacity, and rapid adsorption of toxic and harmful volatile substances in electrolytes are achieved. In particular, it has high specificity for adsorption of HF, PF5, FEC, and carbonates, avoiding competitive adsorption. The separation effect is far superior to activated carbon and molecular sieves. High adsorption efficiency: MOF materials have a large specific surface area and abundant adsorption sites, resulting in fast adsorption rate and high adsorption capacity; Recyclable: Low-temperature desorption does not damage the framework of MOF materials, enabling the MOF materials to be recycled and regenerated, thus forming a closed-loop recycling system with multiple cycles and high capacity retention, solving the problem of short lifespan of traditional adsorbents and improving economic efficiency; Low temperature and energy saving: The desorption temperature is much lower than that of traditional processes, resulting in low energy consumption and no thermal decomposition. This avoids the thermal decomposition of the electrolyte, and the electrolyte can be recovered with high purity (≥98%). Environmentally friendly and safe: Closed collection + targeted adsorption + centralized recycling, no secondary pollution, meeting the environmental protection requirements for power battery recycling; Highly adaptable to engineering applications: It can be directly connected to existing physical dismantling lines to build a complete closed collection-directional adsorption-centralized recycling system that matches the physical dismantling lines. It has a high degree of automation and is suitable for industrial promotion. Attached Figure Description

[0017] Figure 1 This is a flowchart of the method for recovering VOCs from the electrolyte of spent power batteries based on the directional control of the IAST structure of MOF materials in this invention; Figure 2 This is a structural control diagram of the MOF material in this invention; Figure 3 This is a simplified block diagram of the VOCs recovery system in the electrolyte of spent power batteries based on the directional control of the IAST structure of MOF materials in this invention. Figure 4 This is a detailed block diagram of the VOCs recovery system in the electrolyte of spent power batteries based on the directional control of the IAST structure of MOF materials in this invention.

[0018] The attached diagram lists the components represented by each number as follows: 1. Sealed Dismantling and Crushing Unit, 110. Explosion-proof Sealed Dismantling and Crushing Machine, 120. Inert Gas Supply Module, 130. Negative Pressure Exhaust Module; 2. VOCs Pretreatment Unit, 210. Dust Collector, 220. Preheater, 230. Flow Stabilizer; 3. Online Detection and IAST Calculation Unit, 310. GC-MS / Online Detector, 320. IAST Calculation Module; 4. Multi-stage MOF Adsorption Unit, 410. First-stage MOF Adsorption Tower, 420. Second-stage MOF Adsorption Tower, 430. Outlet Concentration Detection Module, 440. Alarm Module; 5. Low-Temperature Desorption Unit, 510. Programmed Temperature Heating Module, 520. Inert Gas Purging Unit; 6. Condensation and Recovery Unit, 610. Condenser, 620. Electrolyte Recovery Storage Tank; 7. Control Unit, 710. PLC Controller, 720. Human-Machine Interface Module, 730. Data Storage Module. Detailed Implementation

[0019] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0020] Example 1: As Figure 1 As shown, a method for recovering VOCs from the electrolyte of spent power batteries based on the directional control of the IAST structure of MOF materials includes the following steps: S1. Disassemble the broken battery cells under closed conditions and continuously extract volatile gases from the disassembly and crushing section to form a mixed gas flow containing electrolyte and VOCs. S2. Real-time detection of each component and concentration in the VOCs mixed gas flow containing electrolyte, and IAST (Ideal Adsorption Solution Theory) selectivity calculation of each target component based on the detection results; S3. Screening or directional control of MOF material structure based on IAST selective calculation results; S4. The selected or directionally controlled MOF material is used to adsorb VOCs in multiple stages. The saturated MOF material is heated and desorbed at a temperature lower than the high temperature regeneration temperature. After desorption, it is cooled to the adsorption temperature to regenerate it. The MOF material can be cycled for adsorption-desorption multiple times, with a high adsorption capacity retention rate. This enables the adsorbent to be recycled and significantly reduces costs. S5. Condense the desorbed gas to recover the electrolyte.

[0021] Example 2: Figure 1 As shown, this embodiment is a further improvement on embodiment 1, as detailed below: In S1, when dismantling a broken battery cell under sealed conditions, an inert protective gas is introduced to create a slightly negative pressure environment. The inert protective gas can be N2 or Ar.

[0022] Example 3: As Figure 1 As shown, this embodiment is a further improvement on embodiment 1 or 2, as detailed below: In S2, GC-MS or online spectroscopy is used to detect the components and concentrations of each component in the VOCs mixed gas flow in real time.

[0023] Furthermore, the IAST selectivity calculation for each target component includes: the adsorption amount and adsorption rate of each target component, and the IAST selectivity coefficient of different MOF materials for toxic components.

[0024] Example 4: Figure 1 , Figure 2 As shown, this embodiment is a further improvement on embodiment 1, 2, or 3, as detailed below: The control methods in S3 include, but are not limited to: channel size control, ligand functional group modification, defect engineering control, and metal node replacement / ligand exchange.

[0025] Furthermore, pore size control aims to match the pore size of MOF materials with the molecular dynamics diameters of HF, PF5, and FEC; ligand functional group modification introduces polar sites that specifically adsorb acidic toxic gases, including -NH2, -OH, and -F; defect engineering control increases the specific surface area and adsorption site density of MOF materials to enhance adsorption rate and capacity; and metal node replacement / ligand exchange dynamically adjusts the IAST selectivity of MOF materials to adapt to different electrolyte systems.

[0026] Example 5: Figure 1 As shown, this embodiment is a further improvement on embodiment 1, 2, 3, or 4, as detailed below: In S4, the multi-stage adsorption of VOCs using MOF materials is specifically as follows: a two-stage fixed bed is used to adsorb VOCs. The first-stage fixed bed uses high-capacity MOF materials selected or directionally controlled to adsorb carbonate organic components. The second-stage fixed bed uses high IAST-selective MOF materials selected or directionally controlled to directionally adsorb HF, PF5, and FEC (fluorinated carbonates). HF and PF5 are acidic gases decomposed by lithium salts. The adsorption temperature and space velocity are controlled to ensure that the outlet concentration meets the standards.

[0027] Furthermore, the desorption of saturated MOF materials in S4 at temperatures below the high-temperature regeneration temperature specifically involves: Saturated MOF materials were subjected to programmed heating desorption at 80℃~150℃ (significantly lower than existing high-temperature regeneration), and inert gas purging was used to improve desorption efficiency.

[0028] Example 6: As Figure 3As shown, a VOCs recovery system for waste power battery electrolyte based on the directional control of the IAST structure of MOF materials is used to perform a VOCs recovery method for waste power battery electrolyte based on the directional control of the IAST structure of MOF materials as described in Examples 1-5. The system includes: a closed disassembly and crushing unit 1, a VOCs pretreatment unit 2, an online detection and IAST calculation unit 3, a multi-stage MOF adsorption unit 4, a low-temperature desorption unit 5, and a condensation and recovery unit 6. The closed disassembly and crushing unit 1 is used to disassemble and crush the battery cells. A mixed gas flow containing VOCs from the electrolyte is conveyed within the closed disassembly and crushing unit 1. The VOCs pretreated in the VOCs pretreatment unit 2 are then fed into the multi-stage MOF adsorption unit 4. The online detection and IAST calculation unit 3 monitors the components and concentrations of each component in the pretreated VOCs mixture fed from the VOCs pretreatment unit 2 into the multi-stage MOF adsorption unit 4 in real time. It also performs IAST selectivity calculations on each target component, and based on the IAST selectivity calculation results, selects or directionally controls the MOF material structure. This allows the multi-stage MOF adsorption unit 4 to be filled with MOF materials of different functions, such as the selected or targeted MOF materials. High-capacity MOF materials with controlled parameters are used to adsorb carbonate organic components, while screened or directionally controlled high IAST-selective MOF materials are used to adsorb HF, PF5, and FEC. Then, the saturated MOF materials are desorbed by heating at a temperature lower than the high-temperature regeneration temperature. After desorption, the desorbed gas in the multi-stage MOF adsorption unit 4 is sent to the condensation and recovery unit 6. The low-temperature desorption unit 5 is used to perform low-temperature heating desorption of each stage of saturated MOF materials in the multi-stage MOF adsorption unit 4, specifically: low-temperature heating desorption of high-capacity MOF materials and low-temperature heating desorption of high IAST-selective MOF materials. Each unit is cooled to its adsorption temperature after desorption to regenerate it, and inert gas is used to purge during the low-temperature desorption process. The desorbed gas in the multi-stage MOF adsorption unit 4 is sent to the condensation and recovery unit 6, where the desorbed gas is condensed to recover the electrolyte. The sealed disassembly and crushing unit 1 is electrically connected to the control unit 7, the VOCs pretreatment unit 2 is electrically connected to the control unit 7, the online detection and IAST calculation unit 3 is electrically connected to the control unit 7, the multi-stage MOF adsorption unit 4 is electrically connected to the control unit 7, the low-temperature desorption unit 5 is electrically connected to the control unit 7, and the condensation and recovery unit 6 is electrically connected to the control unit 7.

[0029] Example 7: As Figure 4 As shown, this embodiment is a further improvement on embodiment 6, as detailed below: The sealed dismantling and crushing unit 1 includes: an explosion-proof sealed dismantling and crushing machine 110, the air inlet of which is connected to the air outlet of an inert gas supply module 120, and the air outlet of which is connected to the air inlet of a negative pressure extraction module 130. The explosion-proof sealed dismantling and crushing machine 110 is used to dismantle and crush the battery cells. The inert gas supply module 120 is used to introduce inert protective gas into the explosion-proof sealed dismantling and crushing machine 110 to form a micro-negative pressure environment. The inert protective gas is N2 or Ar. The inert gas supply module 120 can be an inert gas storage tank. The negative pressure extraction module 130 extracts the VOCs mixed gas flow containing electrolyte in the sealed dismantling and crushing unit 1 and sends it to the VOCs pretreatment unit 2. The negative pressure extraction module 130 can be a negative pressure extraction pump. The VOCs pretreatment unit 2 includes a dust collector 210, a preheater 220, and a flow stabilizer 230. The dust collector 210, preheater 220, and flow stabilizer 230 are connected in sequence. The air inlet of the dust collector 210 is connected to the air outlet of the negative pressure extraction module 130. That is, the VOCs mixed airflow containing electrolyte is first sent into the dust collector 210 to remove dust from the VOCs mixed airflow. Then, the preheater 220 preheats the VOCs mixed airflow. Finally, the flow stabilizer 230 stabilizes the VOCs mixed airflow, thus achieving pretreatment of the VOCs mixed airflow. The VOCs mixed airflow in the flow stabilizer 230 is then sent into the multi-stage MOF adsorption unit 4. The online detection and IAST calculation unit 3 includes: a GC-MS / online detector 310, which is electrically connected to the IAST calculation module 320. The GC-MS / online detector 310 is used to detect in real time the components and concentrations of each component in the pretreated VOCs mixed gas flow sent from the VOCs pretreatment unit 2 into the multi-stage MOF adsorption unit 4, and sends the detection results to the IAST calculation module 320. The IAST calculation module 320 performs IAST selectivity calculation on each target component based on the detection results, and screens or directionally controls the MOF material structure based on the IAST selectivity calculation results. The IAST calculation module 320 sends the IAST selectivity calculation results and MOF control instructions to the PLC controller 710 in the control unit 7. The multi-stage MOF adsorption unit 4 includes: a primary MOF adsorption tower 410, a secondary MOF adsorption tower 420, an outlet concentration detection module 430, and an alarm module 440. The inlet of the primary MOF adsorption tower 410 is connected to the outlet of the flow stabilizer 230. According to calculations, the primary MOF adsorption tower 410 is filled with high-capacity MOF material for adsorbing carbonate organic components. VOCs not fully adsorbed in the primary MOF adsorption tower 410 are sent to the secondary MOF adsorption tower 420. The secondary MOF adsorption tower 420 is filled with high-capacity MOF material for adsorbing carbonate organic components. The high IAST selectivity MOF material for adsorbing HF, PF5, and FEC is used. The outlet of the secondary MOF adsorption tower 420 is connected to the outlet concentration detection module 430. The outlet concentration detection module 430 is used to detect the outlet concentration of the secondary MOF adsorption tower 420 and send the detection signal to the PLC controller 710 in the control unit 7. The alarm module 440 is electrically connected to the PLC controller 710 in the control unit 7. When the outlet concentration exceeds the standard, the PLC controller 710 in the control unit 7 sends an alarm signal to the alarm module 440. The low-temperature desorption unit 5 includes a programmed temperature rise heating module 510 and an inert gas purging unit 520. The programmed temperature rise heating module 510 is used to perform low-temperature heating desorption of the saturated high-capacity MOF material in the primary MOF adsorption tower 410 at 80℃~150℃, and then cools it to the adsorption temperature to regenerate it after desorption. The programmed temperature rise heating module 510 is also used to perform low-temperature heating desorption of the saturated high IAST selective MOF material in the secondary MOF adsorption tower 420 at 80℃~150℃, and then cools it to the adsorption temperature to regenerate it after desorption. The inert gas purging unit 520 is used to purge the primary MOF adsorption tower 410 with inert gas; this can be understood as the inert gas purging unit 520 purging the primary MOF... Inert gas is supplied to the adsorption tower 410 to purge high-capacity MOF materials. The inert gas purging unit 520 is used to purge the secondary MOF adsorption tower 420 with inert gas. This can be understood as: the inert gas purging unit 520 supplies inert gas to the secondary MOF adsorption tower 420 to purge high IAST-selective MOF materials. The condensation and recovery unit 6 includes a condenser 610 and an electrolyte recovery storage tank 620. The desorbed gases in the primary MOF adsorption tower 410 and the secondary MOF adsorption tower 420 are respectively sent to the condenser 610. The condenser 610 condenses the desorbed gases and sends the condensate (electrolyte) to the electrolyte recovery storage tank 620. The purity of the recovered electrolyte is ≥98%. Control unit 7 includes: a PLC controller 710, a human-machine interface module 720, and a data storage module 730. The human-machine interface module 720 and the data storage module 730 are electrically connected to the PLC controller 710. The human-machine interface module 720 is used for human-machine interaction with the PLC controller 710, and the data storage module 730 is used to store operating parameters. The PLC controller 710 is electrically connected to the explosion-proof sealed dismantling and crushing machine 110, the VOCs pretreatment unit 2, the GC-MS / online detector 310, the IAST calculation module 320, the primary MOF adsorption tower 410, the secondary MOF adsorption tower 420, the outlet concentration detection module 430, the alarm module 440, the programmed temperature rise heating module 510, the inert gas purging unit 520, and the condenser 610. The PLC controller 710 can control the explosion-proof sealed dismantling and crushing machine 110, the VOCs pretreatment unit 2, the GC-MS / online detector 310, the IAST calculation module 320, the primary MOF adsorption tower 410, the secondary MOF adsorption tower 420, the outlet concentration detection module 430, the alarm module 440, the programmed temperature rise heating module 510, the inert gas purging unit 520, and the condenser 610 respectively. When the S / online detector 310 is working, the IAST calculation module 320 can send control commands to the PLC controller 710. The primary MOF adsorption tower 410 and the secondary MOF adsorption tower 420 can send adsorption saturation signals to the PLC controller 710. The PLC controller 710 can send purging commands to the inert gas purging unit 520 and desorption commands to the programmed heating module 510. The outlet concentration detection module 430 is used to detect the outlet concentration of the secondary MOF adsorption tower 420 and send the detection signal to the PLC controller 710. During debugging, it serves as a data reference for adjusting the adsorption performance of the MOF material. During production, it serves as the basis for distinguishing between direct discharge and condensation. If the MOF fails, i.e., when the outlet concentration exceeds the standard, the PLC controller 710 sends an alarm signal to the alarm module 440. The PLC controller 710 can also send control signals to the condenser 610.

[0030] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for recovering VOCs from the electrolyte of spent power batteries based on the directional control of the IAST structure of MOF materials, characterized in that, Includes the following steps: S1. Disassemble the broken battery cells under closed conditions and extract the volatile gases in the disassembly and crushing section to form a mixed gas flow containing electrolyte and VOCs. S2. Real-time detection of each component and concentration in the VOCs mixed gas flow containing electrolyte, and IAST selectivity calculation of each target component based on the detection results; S3. Screening or directional control of MOF material structure based on IAST selective calculation results; S4. The selected or directionally controlled MOF material is used to adsorb VOCs in multiple stages. The saturated MOF material is heated and desorbed at a temperature lower than the high temperature regeneration temperature. After desorption is completed, it is cooled to the adsorption temperature to regenerate it. S5. Condense the desorbed gas to recover the electrolyte.

2. The method for VOCs recovery from spent power battery electrolyte based on the directional control of the IAST structure of MOF material according to claim 1, characterized in that, In S1, when dismantling a broken battery cell under sealed conditions, an inert protective gas is introduced to create a slightly negative pressure environment. The inert protective gas is N2 or Ar.

3. The method for VOCs recovery from spent power battery electrolyte based on the directional control of the IAST structure of MOF material according to claim 1, characterized in that, In S2, GC-MS or online spectroscopy is used to detect the components and concentrations of VOCs in the mixed gas stream in real time.

4. The method for VOCs recovery from spent power battery electrolyte based on the directional control of the IAST structure of MOF material according to claim 1, characterized in that, The IAST selectivity calculation for each target component includes: the adsorption amount and adsorption rate of each target component, and the IAST selectivity coefficient of different MOF materials for toxic components.

5. The method for VOCs recovery from spent power battery electrolyte based on the directional control of the IAST structure of MOF material according to claim 1, characterized in that, The control methods in S3 include, but are not limited to: channel size control, ligand functional group modification, defect engineering control, and metal node replacement / ligand exchange.

6. The method for VOCs recovery from spent power battery electrolyte based on the directional control of the IAST structure of MOF material according to claim 5, characterized in that, Pore ​​size control aims to match the pore size of MOF materials with the molecular dynamics diameters of HF, PF5, and FEC; ligand functional group modification introduces polar sites that specifically adsorb acidic toxic gases, including -NH2, -OH, and -F; and defect engineering control increases the specific surface area and adsorption site density of MOF materials.

7. The method for VOCs recovery from spent power battery electrolyte based on the directional control of the IAST structure of MOF material according to claim 1, characterized in that, The S4 uses MOF materials for multi-stage adsorption of VOCs, specifically by employing a two-stage fixed bed for VOCs adsorption. The first-stage fixed bed uses high-capacity MOF materials to adsorb carbonate organic components, while the second-stage fixed bed uses high IAST-selective MOF materials to directionally adsorb HF, PF5, and FEC.

8. The method for VOCs recovery from spent power battery electrolyte based on the directional control of the IAST structure of MOF material according to claim 1, characterized in that, In S4, the desorption of saturated MOF materials by heating at a temperature below the high-temperature regeneration temperature is specifically as follows: Saturated MOF materials were subjected to programmed heating desorption at 80℃~150℃ and purged with inert gas.

9. A VOCs recovery system from waste power battery electrolyte based on the directional control of the IAST structure of MOF materials, characterized in that, The method for recovering VOCs from the electrolyte of spent power batteries based on the directional regulation of the IAST structure of MOF materials, as described in any one of claims 1 to 8, comprises: a closed dismantling and crushing unit (1), a VOCs pretreatment unit (2), an online detection and IAST calculation unit (3), a multi-stage MOF adsorption unit (4), a low-temperature desorption unit (5), and a condensation and recovery unit (6). The VOCs mixed gas flow containing the electrolyte in the closed dismantling and crushing unit (1) is fed into the VOCs pretreatment unit (2), and the pretreated VOCs in the VOCs pretreatment unit (2) are fed into the multi-stage MOF adsorption unit (4). The online detection and IAST calculation unit (3) is used to... The components and concentrations of each pretreated VOCs fed into the multi-stage MOF adsorption unit (4) by the VOCs pretreatment unit (2) are detected in real time, and IAST selectivity calculations are performed on each target component; the low-temperature desorption unit (5) is used to perform low-temperature heating desorption on each stage of saturated MOF materials in the multi-stage MOF adsorption unit (4); the desorbed gas in the multi-stage MOF adsorption unit (4) is sent into the condensation recovery unit (6); the sealed disassembly and crushing unit (1), VOCs pretreatment unit (2), online detection and IAST calculation unit (3), multi-stage MOF adsorption unit (4), low-temperature desorption unit (5) and condensation recovery unit (6) are electrically connected to the control unit (7).

10. A VOCs recovery system for waste power battery electrolyte based on the directional control of the IAST structure of MOF material according to claim 9, characterized in that, The sealed dismantling and crushing unit (1) includes: an explosion-proof sealed dismantling and crushing machine (110), the air inlet of which is connected to the air outlet of an inert gas supply module (120), and the air outlet of which is connected to the air inlet of a negative pressure extraction module (130); the VOCs pretreatment unit (2) includes: a dust collector (210), a preheater (220) and a flow stabilizer (230) connected in sequence, the air inlet of which is connected to the air outlet of a negative pressure extraction module (130); the online detection and IAST calculation unit (3) includes: a GC-MS / online detector (310), which is electrically connected to an IAST calculation module (320); The multi-stage MOF adsorption unit (4) includes: a primary MOF adsorption tower (410) and a secondary MOF adsorption tower (420). The inlet of the primary MOF adsorption tower (410) is connected to the outlet of the flow stabilizer (230). The primary MOF adsorption tower (410) is filled with high-capacity MOF material for adsorbing carbonate organic components. VOCs that are not fully adsorbed in the primary MOF adsorption tower (410) are sent to the secondary MOF adsorption tower (420). The secondary MOF adsorption tower (420) is filled with high IAST selective MOF material for adsorbing HF, PF5, and FEC. The low-temperature desorption unit (5) includes a programmed temperature rise heating module (510) and an inert gas purging unit (520). The programmed temperature rise heating module (510) is used to perform low-temperature heating desorption of saturated high-capacity MOF material in the primary MOF adsorption tower (410) at 80℃ to 150℃. The programmed temperature rise heating module (510) is used to perform low-temperature heating desorption of saturated high IAST selective MOF material in the secondary MOF adsorption tower (420) at 80℃ to 150℃. The inert gas purging unit (520) is used to purge inert gas into the primary MOF adsorption tower (410) and the secondary MOF adsorption tower (420) respectively. The condensation recovery unit (6) includes a condenser (610) and an electrolyte recovery storage tank (620). The desorbed gas in the primary MOF adsorption tower (410) and the secondary MOF adsorption tower (420) is respectively sent into the condenser (610), and the condensate in the condenser (610) is sent into the electrolyte recovery storage tank (620). The control unit (7) includes: a PLC controller (710) and a human-machine interaction module (720) and a data storage module (730) electrically connected to the PLC controller (710). The PLC controller (710) is electrically connected to the explosion-proof sealed dismantling crusher (110), the VOCs pretreatment unit (2), the GC-MS / online detector (310), the IAST calculation module (320), the first-stage MOF adsorption tower (410), the second-stage MOF adsorption tower (420), the programmed temperature rise heating module (510), the inert gas purging unit (520), and the condenser (610).

Images