A waste gas treatment device for retired lithium battery recycling and a condensation access control method

Abstract

The present application relates to the technical field of waste gas treatment of retired lithium battery recycling, and discloses a waste gas treatment device for retired lithium battery recycling and a condensation access control method. The method comprises the following steps: after anhydrous pre-defluorination of fluorine-containing organic waste gas, the waste gas is allowed to enter a pre-stage condensation; the pre-stage condensate enters a liquid phase verification unit and detects pollution indexes, and obtains a pre-defluorination breakthrough trend parameter. When the pollution indexes and the breakthrough trend parameter both satisfy corresponding preset conditions, a post-stage opening trigger condition is formed, the closing constraint of a post-stage inlet normally closed interlocking valve is removed, and the waste gas after pre-stage condensation is allowed to enter a post-stage low-temperature condensation process; when the condition is not formed or disappears, the post-stage inlet normally closed interlocking valve is kept closed or reset to be closed. The present application can reduce the risk of corrosion of equipment and pollution of condensate caused by fluorine-containing acid components entering the post-stage low-temperature condensation process.

Description

Technical Field

[0001] This invention relates to the field of waste gas treatment technology for retired lithium battery recycling, and in particular to a waste gas treatment device for retired lithium battery recycling and its condensation access control method. Background Technology

[0002] Retired lithium batteries may generate fluorinated organic waste gas during dismantling, crushing, sorting, drying, low-temperature volatilization, heat treatment, or electrolyte recovery. This type of waste gas typically contains volatile carbonate organic solvents and may be accompanied by… Fluorinated acidic components, etc. If these components enter the cryogenic condensation equipment without effective control, they can easily cause condenser corrosion, condensate contamination, and a decline in the quality of subsequent recovery.

[0003] Among the relevant waste gas treatment methods, some involve pre-treating the waste gas before sending it into a multi-stage condensation process, while others primarily rely on the concentration of fluorine in the gas phase to determine the waste gas state. Other technologies determine the recovery, discharge, or diversion of the condensate by detecting its pH, conductivity, or other indicators. However, these methods typically lack access control targeting the inlet of the subsequent low-temperature condensation stage, and especially lack a control mechanism that uses both the contamination status of the preceding condensate and the pre-defluorination penetration trend as the opening conditions for the subsequent low-temperature condensation stage.

[0004] Therefore, it is necessary to provide a waste gas treatment device for the recycling of retired lithium batteries and its condensation access control method that can reduce the risk of fluorinated acidic components entering the subsequent low-temperature condensation process and can maintain or restore physical blockage under abnormal conditions. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a waste gas treatment device for the recycling of retired lithium batteries and a condensation access control method thereof, which can form condensation access control at the inlet of the subsequent low-temperature condensation stage, reducing the risk of unverified fluorinated acidic components entering the subsequent low-temperature condensation process.

[0006] To achieve the above objectives, the present invention provides a condensation access control method for a waste gas treatment device for the recycling of retired lithium batteries, comprising: Anhydrous pre-fluorination is performed on the fluorine-containing organic waste gas generated during the recycling of retired lithium batteries. The fluorine-containing organic waste gas after anhydrous pre-defluorination is allowed to enter the pre-stage condensation process, and the normally closed interlock valve of the post-stage inlet, which is located upstream of the post-stage low-temperature condensation inlet, is kept closed before the post-stage opening trigger condition is formed, so as to restrict the waste gas after pre-stage condensation from entering the post-stage low-temperature condensation process before the post-stage opening trigger condition is formed. The forestage condensate generated during the forestage condensation process is introduced into the liquid phase verification unit, which is used to receive the forestage condensate and provide the location for detecting pollution indicators. The contamination indicators of the pre-stage condensate were detected, and the pre-defluorination breakthrough trend parameters were obtained; The subsequent opening triggering conditions include at least the following: the pollution index of the preceding condensate meets the corresponding preset conditions, and the pre-defluorination breakthrough trend parameter meets the corresponding preset conditions. When the downstream opening trigger condition is formed, the closing constraint of the normally closed interlock valve at the downstream inlet is released, allowing the exhaust gas after the upstream condensation to enter the downstream low-temperature condensation process. When the contamination index of the pre-stage condensate does not meet the corresponding preset conditions, or when the pre-defluorination penetration trend parameter does not meet the corresponding preset conditions, the subsequent stage opening trigger condition is not formed; wherein, when the normally closed interlock valve at the downstream inlet is not released from its closing constraint, the normally closed interlock valve at the downstream inlet is kept closed; when the normally closed interlock valve at the downstream inlet has been released from its closing constraint, the normally closed interlock valve at the downstream inlet is reset and closed.

[0007] The present invention also provides a waste gas treatment device for recycling retired lithium batteries, comprising: an anhydrous pre-defluorination unit, a pre-stage condensation unit, a post-stage low-temperature condensation unit, a liquid phase verification unit, a condensate contamination detection component, a gas phase detection unit, a post-stage inlet normally closed interlock valve, a reset component, and a control unit.

[0008] The anhydrous pre-defluorination unit is used to perform anhydrous pre-defluorination on fluorine-containing organic waste gas generated during the recycling of retired lithium batteries; the pre-stage condensation unit is located downstream of the anhydrous pre-defluorination unit; the post-stage cryogenic condensation unit is located downstream of the pre-stage condensation unit; the liquid phase verification unit is connected to the condensate outlet of the pre-stage condensation unit and is used to receive the pre-stage condensate; the condensate contamination detection component is used to detect the contamination index of the pre-stage condensate; the gas phase detection unit is used to obtain the pre-defluorination penetration trend parameter; the post-stage inlet normally closed interlock valve is located upstream of the inlet of the post-stage cryogenic condensation unit and remains closed when the post-stage opening trigger condition is not met; the reset component is used to reset the post-stage inlet normally closed interlock valve to the closed state; the control unit is used to control the post-stage inlet normally closed interlock valve to remain closed, release the closing constraint, or reset the closure according to the pre-stage condensate contamination index and the pre-defluorination penetration trend parameter.

[0009] The beneficial effects of the present invention include at least the following: First, the pre-stage condensate not only serves as a condensation product but also as a liquid-phase access verification medium before the subsequent low-temperature condensation is opened, enabling the identification of condensate phase contamination risks that may not be fully reflected by gas phase detection.

[0010] Second, the pre-defluorination breakthrough trend parameter is used to reflect the operating status of the anhydrous pre-defluorination unit or its approach to breakthrough risk. Together with the upstream condensate contamination index, it forms the downstream opening trigger condition, improving the reliability of the downstream opening judgment.

[0011] Third, the normally closed interlock valve at the downstream inlet remains closed until the downstream opening trigger condition is formed, and is reset closed in case of abnormality or loss of trigger signal, thereby forming a physical access constraint for the downstream cryogenic condensation inlet.

[0012] Fourth, by using the flow restriction path and feedback from the downstream condensate contamination index, low-flow access verification can be performed at the initial stage of downstream low-temperature condensation opening, and the system can enter normal opening, maintain flow restriction, reduce flow, or close the system based on the downstream condensate contamination status.

[0013] Fifth, by feeding back the condensate contamination level to the control unit through the condensate diversion unit, the subsequent opening trigger conditions, flow-limiting opening conditions, or reset closing conditions can be corrected, thereby improving the system's operational stability. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the waste gas treatment device for recycling retired lithium batteries provided in an embodiment of the present invention; Figure 2 This is a schematic flowchart of the condensation access control method provided in an embodiment of the present invention; Figure 3 This is a schematic diagram showing the connection relationship between the flow-limiting path and the subsequent low-temperature condensation unit provided in an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the logical relationship of the subsequent open triggering conditions provided in an embodiment of the present invention.

[0015] The reference numerals in the attached figures are explained as follows: 10. Anhydrous pre-defluorination unit; 20. Pre-stage condensation unit; 21. Pre-stage condensate outlet; 30. Liquid phase verification unit; 31. Condensate contamination detection component; 40. Normally closed interlock valve at the downstream inlet; 41. Reset component; 50. Downstream cryogenic condensation unit; 51. Downstream condensate outlet; 60. Control unit; 70. Gas phase detection unit; 80. Flow restriction path; 81. Main path; 90. Condensate diversion unit; 100. Emergency purification unit. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0017] In the description of this invention, it should be understood that the terms "upstream," "downstream," etc., indicate the positional relationship based on the direction of exhaust gas flow, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific positional relationship, and therefore should not be construed as a limitation of this invention.

[0018] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection," "connection," and "setup" should be interpreted broadly. For example, it can refer to direct connection or indirect connection through pipelines, valves, branches, detection chambers, buffer chambers, or other intermediate structures; it can refer to fixed connection or detachable connection; it can refer to mechanical connection or electrical connection, signal connection, or control connection. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0019] The following is for reference. Figures 1 to 4 This invention describes a waste gas treatment device for recycling retired lithium batteries and its condensation access control method provided in an embodiment of the present invention. Wherein, Figure 1 This is a schematic diagram of the overall structure of the waste gas treatment device. Figure 2 This is a flowchart illustrating the condensation access control method. Figure 3 This is a schematic diagram showing the connection relationship between the flow-limiting path and the subsequent low-temperature condensation unit. Figure 4 This is a schematic diagram illustrating the logical relationship of the triggering conditions for subsequent levels.

[0020] It should be noted that in this embodiment of the invention, the downstream low-temperature condensation unit 50 is not an optional condensation device connected to the main gas path, but rather a downstream low-temperature condensation treatment device located downstream of the downstream inlet normally closed interlock valve 40. The main flow of the waste gas is as follows: the fluorinated organic waste gas is treated by the anhydrous pre-defluorination unit 10 and then enters the upstream condensation unit 20. After the waste gas is condensed in the upstream stage, it enters the downstream low-temperature condensation unit 50 through the downstream inlet normally closed interlock valve 40 after meeting the downstream stage opening trigger conditions, and is then discharged from the downstream low-temperature condensation unit 50 to the subsequent purification or emission end. Therefore, the downstream inlet normally closed interlock valve 40 controls whether the waste gas condensed in the upstream stage is allowed to enter the downstream low-temperature condensation unit 50, rather than simply controlling whether the waste gas is directly discharged.

[0021] like Figure 1 As shown, the waste gas treatment device for recycling retired lithium batteries provided in this embodiment of the invention may include an anhydrous pre-defluorination unit 10, a pre-condensation unit 20, a liquid phase verification unit 30, a condensate contamination detection component 31, a gas phase detection unit 70, a normally closed interlock valve 40 at the downstream inlet, a reset component 41, a downstream low-temperature condensation unit 50, and a control unit 60. The waste gas treatment device may also include a flow restriction path 80, a main passage 81, a condensate diversion unit 90, and an emergency purification unit 100.

[0022] The anhydrous pre-defluorination unit 10 is used to perform anhydrous pre-defluorination on the fluorinated organic waste gas generated during the recycling of retired lithium batteries. The fluorinated organic waste gas can originate from the dismantling, crushing, sorting, drying, low-temperature volatilization, heat treatment, electrolyte recovery, or other recycling processes of retired lithium batteries. The fluorinated organic waste gas may contain condensable organic components and fluorinated acidic components. The condensable organic components may include at least one of dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, NMP, or other volatile organic compounds. It should be noted that NMP may originate from binders, residual solvents from electrode sheets, or related recycling processes. The fluorinated acidic components may include… or at least one of other fluorinated phosphorus oxides.

[0023] The anhydrous pre-defluorination described in this invention refers to a treatment process that, before the waste gas enters the condensation system, does not use water washing and absorption as the main pre-defluorination treatment step, but instead employs dry adsorption, solid alkaline material defluorination, metal oxide adsorption, or other non-water washing methods to reduce the content of fluorinated acidic components in the waste gas. In this invention, the condensation system may include a pre-stage condensation unit 20 and a post-stage low-temperature condensation unit 50. The anhydrous pre-defluorination unit 10 may include a dry adsorption bed, an alkaline dry defluorination bed, a calcium-containing material bed, a magnesium-containing material bed, a metal oxide bed, a porous adsorption material bed, a composite defluorination material bed, or a combination thereof. The specific materials and structure of the above-mentioned anhydrous pre-defluorination unit 10 can be selected according to the waste gas composition, the concentration of fluorinated acidic components, the treatment air volume, and the system operating requirements.

[0024] It should be noted that the anhydrous pre-defluorination is limited to the main pre-defluorination treatment method before the exhaust gas enters the condensation system. It does not exclude the use of wet absorption, alkaline washing absorption or other wet purification treatments in the emergency purification path, non-condensation purification path or terminal purification path after the normally closed interlock valve 40 at the downstream inlet is closed.

[0025] In some examples of this invention, when the pre-defluorination penetration trend parameter indicates that the anhydrous pre-defluorination unit 10 is close to penetration, or when the condensate diversion unit 90 reports a high level of contamination for multiple consecutive condensation stages, the control unit 60 can output a prompt signal indicating that the anhydrous pre-defluorination unit 10 should be replaced, regenerated, switched to a backup defluorination channel, or that the emergency purification unit 100 should be activated. After the anhydrous pre-defluorination unit 10 has completed replacement, regeneration, or backup channel switching, the control unit 60 can re-acquire the pre-defluorination penetration trend parameter and, in conjunction with the upstream condensate contamination index, re-determine whether the downstream opening trigger condition has been formed. Before the re-determination is completed, the downstream inlet normally closed interlock valve 40 remains closed. This prevents the downstream low-temperature condensation unit 50 from being mistakenly opened while the anhydrous pre-defluorination unit 10 is in the process of replacement, regeneration, switching, or recovery confirmation.

[0026] The pre-condensation unit 20 is located downstream of the anhydrous pre-defluorination unit 10 and is used for pre-condensation of the fluorinated organic waste gas after anhydrous pre-defluorination. The pre-condensation unit 20 may include a heat exchanger, a condenser, a cooling coil, a condensation chamber, a shell-and-tube condenser, a plate condenser, or a combination thereof. The pre-condensation unit 20 is used to condense at least a portion of the condensable organic components in the waste gas and discharges the pre-condensate through the pre-condensate outlet 21.

[0027] The downstream cryogenic condensing unit 50 is located downstream of the upstream condensing unit 20. The condensation temperature of the downstream cryogenic condensing unit 50 can be lower than that of the upstream condensing unit 20, or the condensation depth of the downstream cryogenic condensing unit 50 can be greater than that of the upstream condensing unit 20. The downstream cryogenic condensing unit 50 can be used for further condensation and recovery of low-boiling-point organic components or residual condensable organic components after upstream condensation. The downstream cryogenic condensing unit 50 may include a cryogenic condenser, a cold trap, a cryogenic heat exchanger, a multi-stage cryogenic condenser, or a combination thereof. The downstream cryogenic condensing unit 50 may be provided with a downstream condensate outlet 51.

[0028] In some examples of the present invention, the protected object of the downstream cryogenic condensation unit 50 may include the heat exchange surface of the downstream cryogenic condensation unit 50, the inner wall of the cryogenic cold trap, the condensate collection section, the drain pipe, the seals, the valves, the temperature detection components, the pressure detection components, the downstream purification components, or the cryogenic pipeline connected to the downstream cryogenic condensation unit 50.

[0029] By installing a normally closed interlock valve 40 at the downstream inlet of the downstream cryogenic condensation unit 50, and using the contamination index of the upstream condensate and the pre-defluorination breakthrough trend parameters as the criteria for access control, the risk of fluorinated acidic components, hydrolyzed acidic components, ionic contaminants, or fluorinated byproducts accumulating in the aforementioned components under low-temperature conditions can be reduced. Therefore, the condensation access control of this invention not only improves the stability of organic component recovery but also reduces the risks of corrosion, blockage, contaminated condensate accumulation, and increased maintenance frequency in the downstream cryogenic condensation unit 50 and its downstream components.

[0030] The liquid phase verification unit 30 is connected to the pre-stage condensate outlet 21 of the pre-stage condensation unit 20, and is used to receive the pre-stage condensate generated during the pre-stage condensation process and provide a detection location for contamination indicators of the pre-stage condensate. The liquid phase verification unit 30 may include at least one of the following: a pre-stage condensate verification chamber, a detection pool, a sampling passage, an online detection section, a bypass detection chamber, a temporary storage detection chamber, or a condensate collection section with an online detection interface.

[0031] It should be noted that the detection of pollution indicators in the pre-stage condensate by the liquid phase verification unit 30 is not solely for determining the recovery, discharge, or diversion destination of the pre-stage condensate itself, but rather for determining whether the exhaust gas after pre-stage condensation meets the access requirements for entering the subsequent low-temperature condensation process. Therefore, the pre-stage condensate, as a liquid phase verification medium, can participate in the access judgment before the inlet of the subsequent low-temperature condensation process is opened.

[0032] Furthermore, the contamination index of the pre-stage condensate is used in this invention as the liquid phase access criterion for the subsequent low-temperature condensation inlet. That is to say, the liquid phase verification unit 30 is not only used for classifying the quality of the condensate or judging its discharge, but also uses the pre-stage condensate to verify the presence of fluoride-containing acidic contaminants, hydrolytic contaminants, ionic contaminants, or abnormal organic components that have entered the condensation phase, and uses the verification result to inversely constrain whether the exhaust gas after the pre-stage condensation is allowed to enter the subsequent low-temperature condensation unit 50.

[0033] Therefore, even if the forestage condensate can eventually enter the condensate diversion unit 90 for recycling, rework, contamination collection, or hazardous waste treatment, the contamination index of the forestage condensate remains one of the essential criteria for determining the inlet access of the subsequent low-temperature condenser. This control logic differs from the condensate diversion control method, which determines the condensate flow direction solely based on condensate detection results.

[0034] Unlike methods that rely solely on the concentration of fluorine in the gas phase to determine whether a product enters the subsequent condensation stage, this invention detects contamination indicators in the preceding condensate, enabling the liquid phase verification unit 30 to identify any fluorine-containing acidic contamination, hydrolytic contamination, ionic contamination, or abnormal organic components that have already entered the condensation phase. Therefore, even if the gas phase detection value is within the acceptable range, but the preceding condensate shows an increasing trend in contamination, the control unit 60 can still prevent the subsequent cryogenic condensation unit 50 from opening, thereby reducing the risk of corrosion or contamination of the subsequent cryogenic condensation unit 50 by fluorine-containing acidic components.

[0035] It should be noted that this invention does not replace gas phase detection with liquid phase detection, nor does it replace liquid phase detection with gas phase detection. Instead, it uses the condensate contamination state reflected by the pre-stage condensate contamination index and the gas phase defluorination state reflected by the pre-defluorination breakthrough trend parameter as the basis for determining the access of the downstream cryogenic condenser inlet. The pre-stage condensate contamination index reflects fluorine-containing acidic contamination, hydrolysis contamination, ionic contamination, or abnormal organic components that have entered the condensate phase. The pre-defluorination breakthrough trend parameter reflects the defluorination capacity of the anhydrous pre-defluorination unit 10, its approach to breakthrough state, or the risk of gas phase fluorine contamination. Both reflect the contamination risk at different locations and in different phases. If any risk is not eliminated, the normally closed interlock valve 40 at the downstream inlet will not be released from its closure constraint. Therefore, this invention uses liquid phase verification and gas phase trend confirmation to jointly form the access control of the downstream cryogenic condenser inlet, rather than relying on a single phase detection result for downstream opening.

[0036] In some examples of the present invention, an online detection sensor is provided within the liquid phase verification unit 30, or the liquid phase verification unit 30 is connected to the online detection sensor. The online detection sensor can serve as a condensate contamination detection component 31, used to detect contamination indicators of the upstream condensate. The upstream condensate contamination indicators may include at least one of fluoride ion concentration, pH, conductivity, acidity, moisture content, turbidity, or organic component composition.

[0037] In some examples of this invention, the abnormal organic component composition may include at least one of the following: the proportion of target recyclable solvent is lower than a set proportion, the proportion of aqueous by-products is higher than a set proportion, the peak area of ​​fluorine-containing organic by-products is higher than a set proportion, the peak area of ​​unknown impurities is higher than a set proportion, the proportion of low-boiling-point abnormal components is higher than a set proportion, or the proportion of acidic hydrolysis by-products is higher than a set proportion. The organic component composition can be determined by online chromatography, offline sampling chromatography, infrared analysis, mass spectrometry, or other detection methods capable of reflecting changes in the composition of the condensate.

[0038] In some examples of this invention, the online detection sensor may include a fluoride ion selective electrode, a pH sensor, a conductivity sensor, an acidity detection component, a moisture detection component, a turbidity detection component, an online chromatographic analyzer, or other detection components capable of reflecting the contamination status of the condensate. Using these detection components, it can be determined whether the upstream condensate contains fluoride-containing acidic contamination, ion contamination, has a risk of hydrolysis, or exhibits abnormal organic components.

[0039] In some examples of the present invention, the liquid phase verification unit 30 may also be provided with a liquid level detection component, a sampling validity detection component, or a detection status confirmation component. When the preceding stage condensate does not reach the minimum detection liquid level of the liquid phase verification unit 30, the preceding stage condensate sample volume is insufficient, the contamination index detection signal is invalid, or the liquid phase verification unit 30 has not completed effective sampling, the control unit 60 may determine that the preceding stage condensate contamination index does not meet the corresponding preset conditions, thereby preventing the formation of the subsequent stage opening trigger condition.

[0040] In some examples of the present invention, the effective sampling may include: the pre-stage condensate has entered the effective detection position of the liquid phase verification unit 30, the condensate level in the liquid phase verification unit 30 has reached the minimum detection level, the condensate contamination detection component 31 has completed at least one effective sampling, and the sampling data is not in a state of disconnection, over-range, drift abnormality, sensor failure, sampling pipeline blockage or detection chamber lack of liquid.

[0041] When the liquid phase verification unit 30 fails to establish effective detection conditions, even if the pre-defluorination breakthrough trend parameter detected by the gas phase detection unit 70 meets the corresponding preset conditions, the control unit 60 still determines that the downstream opening trigger condition has not been formed, and keeps the downstream inlet normally closed interlock valve 40 closed. This prevents the downstream cryogenic condensation unit 50 from opening without liquid phase verification due to the lack of liquid phase verification.

[0042] The exhaust gas treatment device may also include a gas phase detection unit 70. The gas phase detection unit 70 may be installed at the inlet, outlet, or internal passage of the anhydrous pre-defluorination unit 10, or on the exhaust gas pipeline between the anhydrous pre-defluorination unit 10 and the pre-condensation unit 20. The gas phase detection unit 70 is used to acquire pre-defluorination penetration trend parameters.

[0043] In some examples of the present invention, the pre-defluorination breakthrough trend parameter may include at least one of the following: pre-defluorination outlet fluorine gas concentration, pre-defluorination outlet fluorine gas concentration change rate, pre-defluorination inlet and outlet fluorine gas concentration difference, pre-defluorination channel pressure difference, cumulative processing time, or cumulative processing air volume. The pre-defluorination inlet and outlet fluorine gas concentration difference can be the difference between the pre-defluorination inlet fluorine gas concentration and the pre-defluorination outlet fluorine gas concentration; a decrease in this difference indicates a decrease in the defluorination capacity of the anhydrous pre-defluorination unit 10 or near-breakthrough. The gas phase detection unit 70 may include at least one of the following: an FTIR detector, an electrochemical fluorine gas sensor, an infrared detector, a cavity ring-down spectrometer, a pressure transmitter, a flow meter, a timing module, or a cumulative air volume statistics module.

[0044] In some examples of the present invention, the pre-defluorination penetration trend parameter can be used not only to determine whether the anhydrous pre-defluorination unit 10 has already experienced penetration, but also to determine whether the anhydrous pre-defluorination unit 10 has a tendency to approach penetration. The tendency to approach penetration may include at least one of the following: the concentration of fluorine-containing gas at the pre-defluorination outlet increases over multiple consecutive detection cycles; the rate of change of the concentration of fluorine-containing gas at the pre-defluorination outlet exceeds the allowable rate of change; the difference in the concentration of fluorine-containing gas between the pre-defluorination inlet and outlet decreases over multiple consecutive detection cycles; the pressure difference in the pre-defluorination channel exceeds the allowable range; the cumulative processing time is close to the allowable processing time; or the cumulative processing air volume is close to the allowable processing air volume.

[0045] When the pre-defluorination penetration trend parameter indicates that the anhydrous pre-defluorination unit 10 has a near-penetration trend, even if the concentration of fluorine-containing gas at the pre-defluorination outlet at a certain moment has not exceeded the forbidden threshold, the control unit 60 can still determine that the pre-defluorination penetration trend parameter does not meet the corresponding preset condition, so that the subsequent stage opening trigger condition is not formed, or the already formed subsequent stage opening trigger condition is invalidated.

[0046] In some examples of the present invention, the condensate contamination detection component 31 may include a main detection component and a calibration detection component, and the gas phase detection unit 70 may also include a main detection component and a calibration detection component. The main detection component and the calibration detection component may employ the same detection principle or different detection principles.

[0047] When the deviation between the detection results of the main detection component and the calibration detection component exceeds a set deviation range, the control unit 60 can determine that the corresponding detection signal is invalid, or determine the subsequent opening trigger condition based on the detection result corresponding to a higher contamination risk. In some examples of the present invention, the control unit 60 can also determine whether the detection signal is valid based on the calibration status, drift status, response time, historical detection deviation, cleaning status, or maintenance status of the detection component. When the detection component is in an uncalibrated, calibration failed, drift exceeded the limit, response abnormal, sampling tube blocked, detection chamber contaminated, or maintenance state, the control unit 60 can determine that the corresponding detection signal is invalid, keeping the subsequent inlet normally closed interlock valve 40 closed or resetting it closed. This reduces the risk of the subsequent cryogenic condensation unit 50 being mistakenly opened due to drift, contamination, blockage, or malfunction of a single detection component.

[0048] The normally closed interlock valve 40 at the downstream inlet is located upstream of the inlet of the downstream cryogenic condensation unit 50. The normally closed interlock valve 40 remains closed unless the downstream opening trigger condition is met, thus restricting exhaust gas from entering the downstream cryogenic condensation unit 50. The normally closed interlock valve 40 can be a solenoid valve, pneumatic valve, electric valve, butterfly valve, ball valve, gate valve, regulating valve, combination valve assembly, or other valve components with normally closed interlocking function.

[0049] It should be noted that the normally closed interlock valve 40 at the downstream inlet in this invention is not only used to regulate the flow rate of exhaust gas entering the downstream cryogenic condensation unit 50, but also to form a physical access constraint at the downstream cryogenic condensation inlet. When the downstream opening trigger condition is not formed, the detection signal is invalid, the trigger signal is lost, or an abnormal operating condition occurs, the normally closed interlock valve 40 at the downstream inlet remains closed or is reset closed, thereby preventing the downstream cryogenic condensation unit 50 from receiving exhaust gas without liquid phase verification and confirmation of the pre-defluorination penetration trend.

[0050] In some examples of the present invention, the downstream inlet normally closed interlock valve 40 can be a single valve or a group of normally closed valves disposed on the main passage 81 and / or the flow restriction passage 80 leading to the downstream cryogenic condensation unit 50, wherein the group of normally closed valves is constrained by the same downstream opening trigger condition. Regardless of whether a single valve or a group of normally closed valves is used, the downstream inlet normally closed interlock valve 40 remains closed until the downstream opening trigger condition is formed, in order to restrict the exhaust gas from entering the downstream cryogenic condensation unit 50 without access verification.

[0051] In some examples of the present invention, the downstream inlet normally closed interlock valve 40 is connected to a reset element 41, or the reset element 41 is integrated into the actuator of the downstream inlet normally closed interlock valve 40. The reset element 41 can be a spring reset element, a pneumatic reset element, an electromagnetic reset element, a hydraulic reset element, a gravity reset element, or a power failure closing, gas failure closing, pressure failure closing, or fail-safe reset structure. When the downstream opening trigger condition disappears, the upstream condensate contamination index does not meet the corresponding preset condition, the pre-defluorination penetration trend parameter does not meet the corresponding preset condition, or the trigger signal is lost, the reset element 41 can reset the downstream inlet normally closed interlock valve 40 to the closed state.

[0052] The control unit 60 is connected to the condensate contamination detection component 31, the gas phase detection unit 70, and the normally closed interlock valve 40 at the downstream inlet. The control unit 60 receives upstream condensate contamination indicators and pre-defluorination breakthrough trend parameters, and determines whether the downstream opening trigger condition is formed. The downstream opening trigger condition includes at least: the upstream condensate contamination indicators meet corresponding preset conditions, and the pre-defluorination breakthrough trend parameters meet corresponding preset conditions.

[0053] In some examples of the present invention, the downstream inlet normally closed interlock valve 40 may also be provided with a valve position feedback component, which is used to provide feedback to the control unit 60 on the open state, closed state, or intermediate abnormal state of the downstream inlet normally closed interlock valve 40. After releasing the closing constraint of the downstream inlet normally closed interlock valve 40, the control unit 60 can confirm whether the downstream inlet normally closed interlock valve 40 has actually entered the permissible flow state based on the valve position feedback component.

[0054] When the control unit 60 does not receive valid opening feedback, or receives feedback of abnormal valve position, incomplete closure, incomplete opening, or loss of valve position feedback signal, the control unit 60 can determine that the downstream opening trigger condition has not been effectively executed, and reset the downstream inlet normally closed interlock valve 40 to close, or allow the exhaust gas to enter the emergency purification unit 100 or the non-condensing purification path. Therefore, the downstream inlet normally closed interlock valve 40 is not only controlled by the opening permission signal output by the control unit 60, but can also form actual valve position confirmation through the valve position feedback component, thereby reducing the risk of valve jamming, actuator failure, or abnormal control signal causing the downstream cryogenic condensing unit 50 to open erroneously.

[0055] In this embodiment of the invention, both the pre-stage condensate contamination index and the pre-defluorination breakthrough trend parameter meeting the corresponding preset conditions are necessary conditions for releasing the closing constraint of the normally closed interlock valve 40 at the downstream inlet. In other words, if the pre-stage condensate contamination index does not meet the corresponding preset conditions, the downstream opening trigger condition will not be formed regardless of whether the pre-defluorination breakthrough trend parameter meets the corresponding preset conditions; similarly, if the pre-defluorination breakthrough trend parameter does not meet the corresponding preset conditions, the downstream opening trigger condition will not be formed regardless of whether the pre-stage condensate contamination index meets the corresponding preset conditions.

[0056] Only when the current stage condensate contamination index meets the corresponding preset conditions, and the pre-defluorination breakthrough trend parameter meets the corresponding preset conditions, will the control unit 60 determine that the downstream opening trigger condition has at least a basis for formation. Therefore, the downstream inlet normally closed interlock valve 40 does not open based on a single detection value, but only releases the closing constraint after both liquid phase verification and gas phase breakthrough trend confirmation meet the requirements.

[0057] In some examples of this invention, the subsequent stage opening trigger condition can be formed within a set stable detection window. The set stable detection window may include two or more consecutive detection cycles, a set time length, or a set number of samples. Within the set stable detection window, the control unit 60 determines that the subsequent stage opening trigger condition has been formed only when the preceding stage condensate contamination index continuously meets the corresponding preset conditions and the pre-defluorination breakthrough trend parameter continuously meets the corresponding preset conditions.

[0058] If, within any detection cycle of the set stable detection window, the upstream condensate contamination index fails to meet the corresponding preset conditions, the pre-defluorination breakthrough trend parameter fails to meet the corresponding preset conditions, the liquid phase verification unit 30 fails to form effective detection conditions, or the gas phase detection unit 70 detects an invalid signal or loses its trigger signal, then the control unit 60 determines that the downstream opening trigger condition has not been formed. This avoids the downstream inlet normally closed interlock valve 40 from being mistakenly opened due to a single instantaneous detection value being qualified.

[0059] When the downstream opening trigger condition is met, the control unit 60 releases the closing constraint of the downstream inlet normally closed interlock valve 40, allowing the exhaust gas condensed in the upstream stage to enter the downstream low-temperature condensation unit 50. When the downstream opening trigger condition is not met or disappears, the control unit 60 keeps the downstream inlet normally closed interlock valve 40 closed or resets it to closed.

[0060] In some examples of the present invention, releasing the closing constraint of the downstream inlet normally closed interlock valve 40 may include: the control unit 60 outputting an opening permission signal to the downstream inlet normally closed interlock valve 40, releasing the electrical interlock, releasing the mechanical interlock, releasing the pneumatic interlock, releasing the hydraulic interlock, releasing the control permission interlock, or putting the normally closed valve group into an openable state.

[0061] It should be noted that the release of the closing constraint does not mean that the downstream inlet normally closed interlock valve 40 can be opened when the downstream opening trigger condition is not formed. The default state of the downstream inlet normally closed interlock valve 40 is the closed state; when the downstream opening trigger condition is not formed, the downstream opening trigger condition disappears, the trigger signal is lost, the detection signal is invalid, or the actuator malfunctions, the downstream inlet normally closed interlock valve 40 remains closed or is reset closed by the action of the reset element 41.

[0062] like Figure 2 As shown, the condensation access control method provided in this embodiment of the invention may include: performing anhydrous pre-defluorination on the fluorine-containing organic waste gas generated during the recycling of retired lithium batteries; allowing the fluorine-containing organic waste gas after anhydrous pre-defluorination to enter the pre-condensation process; detecting the pollution index of the pre-condensate and obtaining the pre-defluorination penetration trend parameter; determining whether the subsequent opening trigger condition is formed; and controlling the normally closed interlock valve 40 at the inlet of the subsequent stage according to the subsequent opening trigger condition.

[0063] Specifically, the fluorinated organic waste gas first enters the anhydrous pre-defluorination unit 10. The anhydrous pre-defluorination unit 10 pre-removes the fluorinated acidic components in the waste gas to reduce the risk of the fluorinated acidic components entering the subsequent condensation system.

[0064] The fluorinated organic waste gas, after anhydrous pre-defluorination, enters the pre-condensation unit 20. The pre-condensation unit 20 performs pre-condensation on the waste gas and produces pre-condensate. The pre-condensation process can be used to recover some of the condensable organic components in the waste gas, while ensuring that pollutants that may enter the condensate phase are reflected in the pre-condensate.

[0065] The fore-stage condensate generated during the pre-condensation process enters the liquid phase verification unit 30, where contamination indicators are detected. Simultaneously, the pre-defluorination breakthrough trend parameters are acquired through the gas phase detection unit 70. Therefore, the control unit 60 can simultaneously obtain liquid phase contamination status information and pre-defluorination operation status information.

[0066] The control unit 60 determines whether the subsequent stage opening trigger condition has been formed. The subsequent stage opening trigger condition includes at least the following: the contamination index of the preceding stage condensate meets the corresponding preset condition, and the pre-defluorination penetration trend parameter meets the corresponding preset condition. That is to say, the subsequent stage opening trigger condition is formed only when the contamination state of the preceding stage condensate meets the subsequent stage low-temperature condensation access requirements, and the penetration trend of the anhydrous pre-defluorination unit 10 is within the allowable range.

[0067] When the downstream opening trigger condition is met, the control unit 60 releases the closing constraint of the downstream inlet normally closed interlock valve 40, allowing the exhaust gas after upstream condensation to enter the downstream low-temperature condensation unit 50. When the downstream opening trigger condition is not met, the downstream inlet normally closed interlock valve 40 remains closed. After the downstream inlet normally closed interlock valve 40 has been released from its closing constraint, if the upstream condensate contamination index does not meet the corresponding preset condition, or the pre-defluorination penetration trend parameter does not meet the corresponding preset condition, the control unit 60 determines that the downstream opening trigger condition has disappeared and resets the downstream inlet normally closed interlock valve 40 to its closed state.

[0068] In some examples of the present invention, when the preceding stage condensate does not enter the effective detection position of the liquid phase verification unit 30, the liquid phase verification unit 30 does not reach the minimum detection level, the preceding stage condensate contamination index detection signal is invalid, the pre-defluorination breakthrough trend parameter acquisition fails, the gas phase detection unit 70 detection signal is invalid, the control unit 60 does not receive valid access judgment data, the trigger signal corresponding to the subsequent stage opening trigger condition is lost, the control signal between the control unit 60 and the subsequent stage inlet normally closed interlock valve 40 is interrupted, the device is powered off, the device is gas-off, the actuator loses pressure, or the reset element 41 is activated, the control unit 60 determines that the subsequent stage opening trigger condition has not been formed or has disappeared, and keeps the subsequent stage inlet normally closed interlock valve 40 closed or reset closed.

[0069] Therefore, the downstream cryogenic condensation unit 50 will not be opened when the detection data is missing, the detection data is invalid, or the trigger signal is abnormal, thus forming a fail-safe condensation access control.

[0070] In some examples of the present invention, the pollution indicators of the pre-stage condensate meeting the corresponding preset conditions may include: the fluoride ion concentration of the pre-stage condensate is not higher than the allowable fluoride ion concentration, the pH is within the allowable range, the conductivity is not higher than the allowable conductivity, the acidity is not higher than the allowable acidity, the moisture content is not higher than the allowable moisture content, the turbidity is not higher than the allowable turbidity, or the composition of organic components meets at least one of the recycling requirements.

[0071] In some examples of this invention, the permissible fluoride ion concentration, permissible conductivity, permissible acidity, permissible moisture content, permissible turbidity, and permissible pH range can be determined based on the corrosion resistance level of the subsequent low-temperature condensation unit 50, the condensate recovery quality requirements, maintenance cycle, safety margin, or historical operating data. For example, in one example, the permissible value for the fluoride ion concentration in the preceding condensate can be set to no more than 10 ppm. This value is merely an example and does not constitute a limitation on the scope of protection of this invention.

[0072] In some examples of the present invention, the pre-defluorination penetration trend parameter meeting the corresponding preset conditions may include at least one of the following: the concentration of fluorine-containing gas at the pre-defluorination outlet is not higher than the allowable outlet concentration, the rate of change of the concentration of fluorine-containing gas at the pre-defluorination outlet is not higher than the allowable rate of change, the difference between the concentration of fluorine-containing gas at the pre-defluorination inlet and outlet is not lower than the allowable difference, the pressure difference of the pre-defluorination channel is within the allowable range, the cumulative treatment time is not higher than the allowable treatment time, or the cumulative treatment air volume is not higher than the allowable treatment air volume.

[0073] In some examples of this invention, even if the concentration of fluorine-containing gas at the pre-defluorination outlet has not exceeded the corresponding prohibited threshold, but the conductivity, fluoride ion concentration, or acidity in the preceding condensate exceeds the corresponding allowable pollution range, the control unit 60 still determines that the pollution index of the preceding condensate does not meet the corresponding preset condition, thereby preventing the formation of the subsequent stage opening trigger condition and keeping the normally closed interlock valve 40 at the subsequent stage inlet closed. This avoids relying solely on gas phase detection results while ignoring the actual pollution state of the condensate.

[0074] In some examples of this invention, even if the contamination index of the pre-stage condensate is within the allowable range, if the rate of change of the fluorine-containing gas concentration at the pre-defluorination outlet continues to increase, the difference in fluorine-containing gas concentration between the pre-defluorination inlet and outlet continues to decrease, or the pressure difference in the pre-defluorination channel exceeds the allowable range, the control unit 60 can determine that the pre-defluorination penetration trend parameter does not meet the corresponding preset condition, thereby preventing the formation of the subsequent stage opening trigger condition and keeping the normally closed interlock valve 40 at the subsequent stage inlet closed. This reduces the risk of the subsequent low-temperature condensation unit 50 being opened when the anhydrous pre-defluorination unit 10 approaches penetration. Here, "continuously increasing" or "continuously decreasing" can refer to an increasing or decreasing trend within two or more consecutive detection cycles.

[0075] In some examples of the present invention, the control unit 60 can determine the fluorine leakage load based on the fluorine gas concentration at the pre-defluorination outlet and the waste gas treatment flow rate, and determine the cumulative fluorine intake amount for the stage based on the fluorine leakage load and the condensation stage operating time.

[0076] Specifically, the fluorine leakage load can be expressed as the fluorine contamination load that may enter the subsequent cryogenic condensation process per unit time. In one example, the fluorine leakage load can be determined according to the following formula: L f =k×Cf out ×Q Among them, L f This indicates the fluorine leakage load, where k represents the unit conversion factor or proportionality factor, and Cf... out Q represents the concentration of fluorine-containing gas at the pre-defluorination outlet, and Q represents the waste gas treatment flow rate.

[0077] The cumulative fluorine entry amount per stage can be expressed as the total amount of fluorine contamination that may enter the subsequent low-temperature condensation process during a condensation stage. In one example, the cumulative fluorine entry amount per stage can be determined by the following formula: Af=Σk×Cf out , i ×Q i ×Δt i Among them, A f This indicates the cumulative fluoride content introduced during the stage, where k represents the unit conversion factor or proportionality factor, and Cf... out , i Q represents the concentration of fluorine-containing gas at the pre-defluorination outlet during the i-th sampling period. i Δt represents the exhaust gas treatment flow rate in the i-th sampling period. i This represents the duration of the i-th sampling period.

[0078] It should be noted that when Cf out When expressed in volume fraction, mass concentration, or other concentration units, the unit conversion factor k can be used to convert the concentration of fluorinated gas at the pre-defluorination outlet and the waste gas treatment flow rate into the fluorinated leakage load per unit time. The unit conversion factor k can be determined based on the concentration unit, gas state parameters, type of fluorinated component, or engineering calibration results.

[0079] The above formula is only an exemplary calculation method. The fluorine leakage load and the cumulative fluorine entry amount in each stage can also be determined by other equivalent methods based on the fluorine gas concentration at the pre-defluorination outlet, the waste gas treatment flow rate, the sampling cycle, the gas state parameters, the types of fluorine components, or the engineering calibration model.

[0080] In some examples of the present invention, the permissible fluorine leakage load and the permissible cumulative fluorine ingress amount can be determined based on the corrosion resistance grade of the material of the downstream cryogenic condensation unit 50, the heat exchange area, the condensation temperature, the condensate recovery quality requirements, the operation and maintenance cycle, the design processing capacity of the anhydrous pre-defluorination unit 10, historical operating data, or the safety margin.

[0081] In one example, when the fluorine leakage load is below a first load threshold and the cumulative fluorine inflow during the stage is below a first cumulative threshold, the control unit 60 may allow the downstream cryogenic condensation unit 50 to enter a flow-limited open state; when the fluorine leakage load is below a second load threshold and the cumulative fluorine inflow during the stage is below a second cumulative threshold, and the downstream condensate contamination index meets the normal opening conditions, the control unit 60 may allow the downstream cryogenic condensation unit 50 to enter a normal open state. The first load threshold may be higher than or equal to the second load threshold, and the first cumulative threshold may be higher than or equal to the second cumulative threshold; alternatively, they may be set to the same threshold depending on different operating strategies.

[0082] The aforementioned thresholds can be determined through engineering calibration, trial operation data, corrosion resistance design parameters of the downstream low-temperature condensation unit 50, target condensate quality requirements, or safety margins, and are not limited to a fixed value.

[0083] In some examples of this invention, the subsequent opening triggering conditions may also include a fluorine leakage load not exceeding the permissible fluorine leakage load, and / or a cumulative fluorine entry amount in the stage not exceeding the permissible cumulative fluorine entry amount. By introducing fluorine leakage load and cumulative fluorine entry amount in the stage, situations where the instantaneous detection value is qualified but the cumulative pollution risk in the stage is high can be avoided.

[0084] In some examples of the present invention, the pre-stage condensate contamination index, pre-defluorination penetration trend parameter, fluorine leakage load, stage cumulative fluorine entry amount, or post-stage condensate contamination index can be set with an open threshold and a close threshold, and a hysteresis interval is formed between the open threshold and the close threshold.

[0085] The control unit 60 can allow the formation of a downstream opening trigger condition when the pollution index is below the opening threshold and continuously meets the stable detection requirements, and reset and close the downstream inlet normally closed interlock valve 40 when the pollution index reaches the closing threshold. When the detected value is within the hysteresis range, the control unit 60 can maintain the current state, extend the observation time, maintain the flow-limited opening state, or reduce the exhaust gas treatment flow rate entering the downstream cryogenic condensation unit 50. This reduces the risk of frequent opening and closing of the downstream inlet normally closed interlock valve 40 when the detected value fluctuates near the threshold.

[0086] like Figure 3 As shown, in some examples of the present invention, the exhaust gas treatment device may further include a flow restriction path 80 and a main passage 81. The flow restriction path 80 is connected to the inlet of the downstream cryogenic condensation unit 50 and is used to supply gas to the downstream cryogenic condensation unit 50 at a flow rate lower than the processing flow rate of the downstream cryogenic condensation unit 50 under normal operating conditions during the initial opening of the downstream cryogenic condensation unit 50.

[0087] It should be noted that the flow restriction path 80 is not used to bypass the normally closed interlock valve 40 at the downstream inlet to supply gas to the downstream cryogenic condensing unit 50 before the downstream opening trigger condition is formed. The flow restriction path 80 is only used for low-flow access verification during the initial opening of the downstream cryogenic condensing unit after the downstream opening trigger condition has been formed. The flow restriction valve, throttle valve, or corresponding valve group on the flow restriction path 80 is also constrained by the downstream opening trigger condition and remains closed until the downstream opening trigger condition is formed.

[0088] In this embodiment of the invention, the flow restriction path 80 is a trial opening path after the formation of the subsequent opening trigger condition, rather than a free bypass that bypasses the normally closed interlock valve 40 at the subsequent inlet. When either the current stage condensate contamination index or the pre-defluorination penetration trend parameter fails to meet the corresponding preset condition, the flow restriction path 80 is also in a closed or gas supply-disallowed state.

[0089] After the initial activation conditions for the downstream stage are met, the control unit 60 prioritizes allowing the exhaust gas from the upstream condenser to enter the downstream cryogenic condensation unit 50 at a flow rate lower than the normal open state processing flow rate via the flow-limiting path 80. This is to further verify the actual pollution risk of the downstream cryogenic condensation unit 50 through the downstream condensate pollution index. Only when the downstream condensate pollution index after flow-limiting activation meets the normal open conditions will the control unit 60 allow the downstream cryogenic condensation unit 50 to enter the normal open state.

[0090] In some examples of the present invention, during a condensation stage, when the subsequent stage opening trigger condition is first formed, the control unit 60 may first allow the exhaust gas after the previous stage condensation to enter the subsequent stage low-temperature condensation unit 50 through the flow-limiting path 80, instead of directly allowing the exhaust gas to enter the subsequent stage low-temperature condensation unit 50 through the main passage 81 at the normal processing flow rate.

[0091] In some examples of the present invention, the flow-limiting path 80 may include at least one of the following: a small-diameter branch, a bypass line with a flow-limiting orifice plate, a branch equipped with a flow-limiting valve, a throttling element, or a flow-limiting opening range of a regulating valve. The flow capacity of the flow-limiting path 80 is lower than the flow capacity under normal open conditions of the subsequent cryogenic condenser.

[0092] In some examples of the present invention, after the downstream low-temperature condensation unit 50 is opened through the flow-limiting path 80, the downstream condensate pollution index can be detected, and the downstream low-temperature condensation unit 50 can be controlled to enter a normal open state, maintain a flow-limiting open state, reduce the waste gas treatment flow rate entering the downstream low-temperature condensation unit 50, or close the state according to the downstream condensate pollution index.

[0093] Specifically, the downstream condensate contamination index can be set with normal opening conditions, observation range, and closing threshold. Normal opening conditions correspond to the low contamination risk range, the observation range corresponds to the intermediate risk range, and the closing threshold corresponds to the high contamination risk range. Different downstream condensate contamination indices can have corresponding normal opening thresholds, observation thresholds, and closing thresholds set separately.

[0094] When the downstream condensate pollution index meets the normal opening conditions, the control unit 60 can control the downstream low-temperature condensation unit 50 to enter the normal opening state; when the downstream condensate pollution index is within the observation range, the control unit 60 can maintain the flow-limited opening state; when the downstream condensate pollution index worsens but has not yet reached the closing threshold, the control unit 60 can reduce the exhaust gas treatment flow rate entering the downstream low-temperature condensation unit 50; when the downstream condensate pollution index exceeds the corresponding pollution allowable range or reaches the closing threshold, the control unit 60 can reset and close the downstream inlet normally closed interlock valve 40.

[0095] In some examples of the present invention, the contamination indicators of the downstream condensate may include at least one of the following: fluoride ion concentration, pH, conductivity, acidity, moisture content, turbidity, organic component composition, or fluorine-containing byproduct content in the downstream condensate. The control unit 60 may control the downstream cryogenic condensation unit 50 to one of the following states based on the downstream condensate contamination indicators: normal open state, flow-limited open state, flow-reducing observation state, or closed state.

[0096] The "normal open state" refers to the situation where the downstream condensate contamination index meets the normal opening conditions, and the downstream low-temperature condensation unit 50 can receive the exhaust gas after condensation at the normal processing flow rate. The "limited flow open state" refers to the situation where the downstream condensate contamination index has not yet reached the closing threshold, but further observation is still required; the downstream low-temperature condensation unit 50 only receives exhaust gas at a flow rate lower than the normal processing flow rate. The "reduced flow observation state" refers to the situation where the downstream condensate contamination index worsens compared to the normal open state but has not yet reached the closing threshold; the control unit 60 reduces the exhaust gas processing flow rate entering the downstream low-temperature condensation unit 50. The "closed state" refers to the situation where the downstream condensate contamination index reaches or exceeds the closing threshold; the control unit 60 resets and closes the downstream inlet normally closed interlock valve 40.

[0097] In some examples of the present invention, the control unit 60 can divide the condensation access state of the exhaust gas treatment device into at least one of the following: prohibited access state, pending verification state, flow-limited access state, normal access state, flow-reducing observation state, and emergency purification state.

[0098] The prohibited access state refers to the situation where the downstream opening trigger condition has not been formed or has disappeared, and the downstream inlet normally closed interlock valve 40 remains closed or reset closed. The pending verification state refers to the situation where the upstream condensate pollution index and pre-defluorination penetration trend parameter are being sampled or waiting for a stable detection window to form, and the downstream inlet normally closed interlock valve 40 remains closed. The flow-limited access state refers to the situation where, after the downstream opening trigger condition is formed for the first time, the exhaust gas after upstream condensation enters the downstream low-temperature condensation unit 50 through the flow-limited path 80. The normal access state refers to the situation where the downstream condensate pollution index meets the normal opening condition, and the exhaust gas can enter the downstream low-temperature condensation unit 50 in a normal open state. The flow reduction observation state refers to the situation where the downstream condensate pollution index deteriorates but has not yet reached the closing threshold, and the control unit 60 reduces the exhaust gas treatment flow rate entering the downstream low-temperature condensation unit 50. The emergency purification state refers to the situation where, after the downstream inlet normally closed interlock valve 40 is closed, the exhaust gas enters the emergency purification unit 100 or the non-condensation purification path.

[0099] By dividing the states as described above, the control unit 60 can avoid direct switching between different risk levels, thereby improving the stability of the downstream cryogenic condenser inlet access control.

[0100] In some examples of the present invention, when the current stage condensate contamination index exceeds the corresponding allowable contamination range, or the pre-defluorination penetration trend parameter exceeds the corresponding allowable access range, or when the subsequent stage condensate contamination index exceeds the corresponding allowable contamination range after detection, the control unit 60 may determine that the subsequent stage opening trigger condition has disappeared, or cancel the trigger signal corresponding to the subsequent stage opening trigger condition, so that the normally closed interlock valve 40 at the subsequent stage inlet is reset and closed.

[0101] It should be noted that, in this invention, disabling the downstream opening trigger condition can be understood as determining that the downstream opening trigger condition has disappeared, or canceling the trigger signal corresponding to the downstream opening trigger condition. Therefore, the downstream inlet normally closed interlock valve 40 can be returned from the open state to the closed state when a contamination risk occurs.

[0102] In some examples of this invention, after the normally closed interlock valve 40 at the downstream inlet is reset and closed, the exhaust gas can enter the emergency purification process, or the exhaust gas can enter the non-condensing purification path after being condensed in the upstream stage. The emergency purification process can be implemented by the emergency purification unit 100, or by existing adsorption purification, dry defluorination, alkaline washing absorption, catalytic oxidation, or thermal oxidation treatment paths in the system. The non-condensing purification path can include at least one of adsorption purification, dry defluorination, alkaline washing absorption, catalytic oxidation, thermal oxidation, or other exhaust gas purification methods.

[0103] In some examples of the present invention, when the normally closed interlock valve 40 at the downstream inlet is reset and closed due to abnormal contamination index of the upstream condensate, abnormal pre-defluorination penetration trend parameter, invalid detection signal, lost trigger signal, abnormal valve position feedback, or abnormal contamination index of the downstream condensate, the control unit 60 does not directly restore the normal open state of the downstream low-temperature condensation unit 50.

[0104] The control unit 60 can first reacquire the upstream condensate contamination index and pre-defluorination breakthrough trend parameters. Only after both parameters meet the corresponding preset conditions and pass through a set stable detection window can the exhaust gas after upstream condensation enter the downstream cryogenic condensation unit 50 via the flow-limiting path 80. The control unit 60 only allows the downstream cryogenic condensation unit 50 to resume normal operation when the downstream condensate contamination index meets the normal opening conditions after the flow restriction is lifted, and when the valve position feedback component of the downstream inlet normally closed interlock valve 40 indicates a normal valve position. This prevents the downstream cryogenic condensation unit 50 from directly resuming normal operation without re-verification after an anomaly is resolved.

[0105] In some examples of the present invention, when the detection signal between the control unit 60 and the condensate contamination detection component 31 is invalid, the detection signal between the control unit 60 and the gas phase detection unit 70 is invalid, the trigger signal between the control unit 60 and the downstream inlet normally closed interlock valve 40 is lost, or when the device experiences a power outage, gas outage, or actuator pressure loss, the downstream inlet normally closed interlock valve 40 can be reset to the closed state under the action of the reset member 41. Therefore, even if the downstream opening trigger condition has been formed at the previous moment, the open state of the downstream inlet normally closed interlock valve 40 will not be maintained.

[0106] like Figure 1 As shown, in some examples of the present invention, the exhaust gas treatment apparatus may further include a condensate diversion unit 90. The condensate diversion unit 90 is connected to at least one of the pre-stage condensate outlet 21 of the pre-stage condensation unit 20 and the post-stage condensate outlet 51 of the post-stage cryogenic condensation unit 50.

[0107] In some examples of the present invention, the condensate diversion unit 90 can determine the condensate contamination level based on the contamination index of the preceding condensate, the contamination index of the following condensate, or both, and guide the condensate into different collection, recovery, or treatment paths according to the condensate contamination level. For example, condensate with a low contamination level can enter a qualified recovery tank; condensate with a medium contamination level can enter a rework treatment tank; and condensate with a high contamination level can enter a contaminated condensate collection tank or a hazardous waste treatment path.

[0108] In some examples of this invention, the condensate diversion unit 90 can feed back the condensate contamination level to the control unit 60. The control unit 60 can then adjust the subsequent stage opening trigger conditions, flow-limiting opening conditions, or reset closing conditions based on the condensate contamination level. For example, when the condensate contamination level increases in multiple consecutive condensation stages, the control unit 60 can reduce the allowable fluorine leakage load, reduce the allowable cumulative fluorine entry amount, extend the flow-limiting opening observation time, increase the stringency of the upstream condensate contamination index determination, or trigger the replacement prompt of the anhydrous pre-defluorination unit 10 earlier.

[0109] It should be noted that the condensate diversion unit 90's identification and diversion of condensate contamination levels does not change the role of the upstream condensate contamination index as the basis for determining the downstream low-temperature condensate inlet access. In other words, in this invention, the condensate diversion unit 90 can be used for condensate management, and can also feed back the condensate contamination level to the control unit 60 to correct the subsequent downstream opening trigger conditions, flow-limiting opening conditions, or reset closing conditions.

[0110] In one example, when the condensate diversion unit 90 outputs a high pollution level for multiple consecutive condensation stages, the control unit 60 can increase the strictness of the judgment of the upstream condensate pollution index, reduce the allowable fluorine leakage load, reduce the allowable cumulative fluorine entry amount, extend the flow restriction opening observation time, or trigger the replacement, regeneration, or bypass purification prompt of the anhydrous pre-defluorination unit 10 in advance.

[0111] Therefore, the condensate diversion unit 90 is not only used to determine the destination of the condensate itself, but also participates in the dynamic correction of the inlet access conditions of the subsequent low-temperature condenser.

[0112] In some examples of the present invention, the control unit 60 may also record operational data during the condensate access control process. The operational data may include at least one of the following: upstream condensate contamination index, pre-defluorination penetration trend parameters, fluorine leakage load, cumulative fluorine entry amount per stage, downstream condensate contamination index, valve position feedback status of the downstream inlet normally closed interlock valve 40, open status of the flow restriction path 80, open status of the main passage 81, condensate contamination level, abnormal alarm information, reset closing time, re-access time, or activation status of the emergency purification unit 100.

[0113] The control unit 60 can generate operation records, alarm records, maintenance prompts, or pre-defluorination material replacement prompts based on the operation data. The operation records can be used to subsequently correct the corresponding preset conditions for upstream condensate contamination indicators, the corresponding preset conditions for pre-defluorination breakthrough trend parameters, flow restriction opening conditions, normal opening conditions, or reset closing conditions. This makes the condensate access control traceable and adjustable, and provides a basis for subsequent operation and maintenance, pre-defluorination material replacement, condensate contamination level judgment, and protection of the downstream cryogenic condensation unit 50.

[0114] like Figure 4 As shown, in some examples of this invention, the subsequent stage opening trigger condition can be determined using a logical AND relationship. That is, the subsequent stage opening trigger condition is formed when the current stage condensate contamination index meets the corresponding preset condition and the pre-defluorination penetration trend parameter meets the corresponding preset condition; otherwise, the subsequent stage opening trigger condition is not formed.

[0115] In some examples of this invention, the subsequent opening trigger condition may also include supplementary conditions. Supplementary conditions may include at least one of the following: the fluorine leakage load is not higher than the permissible fluorine leakage load; the cumulative fluorine intake at each stage is not higher than the permissible cumulative fluorine intake; the exhaust gas temperature is within the permissible range; the system pressure is within the permissible range; the dust concentration is not higher than the permissible value; the oxygen content is within the permissible range; or the load of condensable organic components meets the recovery requirements.

[0116] Example 1: Normal access conditions.

[0117] In one operational example, the fluorinated organic waste gas generated during the recycling of retired lithium batteries enters the anhydrous pre-defluorination unit 10, and after defluorination by dry adsorption or solid alkaline materials, it enters the pre-condensation unit 20. The pre-condensate generated by the pre-condensation unit 20 enters the liquid phase verification unit 30 through the pre-condensate outlet 21. The condensate contamination detection unit 31 detects that the fluoride ion concentration in the pre-condensate is not higher than the set fluoride ion concentration threshold, the pH is within the set allowable range, the conductivity is not higher than the set conductivity threshold, and the moisture content is not higher than the set moisture threshold.

[0118] Simultaneously, the gas phase detection unit 70 detects that the concentration of fluorine-containing gas at the pre-defluorination outlet is not higher than the allowable outlet concentration, the rate of change of the concentration of fluorine-containing gas at the pre-defluorination outlet is not higher than the allowable rate of change, and the difference in the concentration of fluorine-containing gas between the pre-defluorination inlet and outlet is not lower than the allowable difference. The control unit 60 determines that the upstream condensate contamination index meets the corresponding preset conditions, and the pre-defluorination penetration trend parameter meets the corresponding preset conditions, thereby determining that the downstream opening trigger condition has been formed.

[0119] When the initial opening trigger condition is first formed, the control unit 60 first releases the closing constraint corresponding to the flow restriction path 80, allowing the exhaust gas after condensation in the preceding stage to enter the subsequent low-temperature condensation unit 50 through the flow restriction path 80. After the subsequent low-temperature condensation unit 50 has been running for a period of observation, if the pollution index of the subsequent condensate meets the normal opening condition, the control unit 60 then allows the exhaust gas to enter the subsequent low-temperature condensation unit 50 in a normal open state.

[0120] Example 2: Liquid phase anomaly rejection of access condition.

[0121] In another operating example, the fluorinated organic waste gas after anhydrous pre-defluorination enters the pre-condensation unit 20, and the pre-condensate enters the liquid phase verification unit 30. The gas phase detection unit 70 detects that the concentration of fluorinated gas at the pre-defluorination outlet does not exceed the allowable outlet concentration, but the condensate contamination detection component 31 detects that the fluoride ion concentration of the pre-condensate is higher than the set fluoride ion concentration threshold, or the pH of the pre-condensate is lower than the set allowable range, or the conductivity of the pre-condensate is higher than the set conductivity threshold.

[0122] At this point, the control unit 60 determines that the pre-stage condensate contamination index does not meet the corresponding preset conditions. Even if the pre-defluorination penetration trend parameter meets the corresponding preset conditions, the subsequent opening trigger condition is not formed, and the normally closed interlock valve 40 at the subsequent inlet remains closed. The exhaust gas after pre-stage condensation can enter the emergency purification unit 100 or enter the non-condensation purification path.

[0123] This control method avoids opening the downstream cryogenic condensation unit 50 simply because the gas phase detection value is within the allowable range, thereby reducing the risk of fluorinated acidic contaminants that have already entered the condensation phase entering the downstream cryogenic condensation process.

[0124] Example 3: Abnormal gas phase penetration trend leads to rejection of access conditions.

[0125] In another operating example, the liquid phase verification unit 30 detected that the contamination index of the pre-stage condensate was within the allowable range, but the gas phase detection unit 70 detected that the concentration of fluorine-containing gas at the pre-defluorination outlet increased in multiple consecutive detection cycles, or the difference between the concentration of fluorine-containing gas at the pre-defluorination inlet and outlet decreased in multiple consecutive detection cycles, or the pressure difference in the pre-defluorination channel exceeded the allowable range, or the cumulative processed air volume approached the allowable processed air volume.

[0126] Control unit 60 determines that the anhydrous pre-defluorination unit 10 has a near-penetration trend, and further determines that the pre-defluorination penetration trend parameter does not meet the corresponding preset conditions. At this time, even if the upstream condensate contamination index meets the corresponding preset conditions, the downstream open trigger condition is not formed, and the downstream inlet normally closed interlock valve 40 remains closed.

[0127] This control method can prevent the opening of the subsequent low-temperature condensation unit 50 in advance when the anhydrous pre-defluorination unit 10 has not been fully penetrated but has shown a tendency to penetrate, thereby reducing the risk of fluorinated acidic components suddenly entering the subsequent low-temperature condensation process.

[0128] Example 4: Detection signal invalid or trigger signal lost.

[0129] In another operating example, the pre-stage condensate in the liquid phase verification unit 30 does not reach the minimum detection level, or the condensate contamination detection unit 31 outputs a disconnection signal, over-range signal, drift abnormal signal, or fault signal; or the gas phase detection unit 70 fails to output a valid pre-defluorination penetration trend parameter; or the trigger signal between the control unit 60 and the normally closed interlock valve 40 at the downstream inlet is interrupted.

[0130] In any of the above situations, the control unit 60 determines that the downstream opening trigger condition has not been formed or has disappeared. If the downstream inlet normally closed interlock valve 40 has not yet opened, it remains closed; if the downstream inlet normally closed interlock valve 40 is already in the open state, it is reset and closed under the action of the reset element 41.

[0131] Therefore, the downstream low-temperature condensation unit 50 will not continue to receive the exhaust gas after the upstream condensation when the detection signal is invalid, the detection conditions are insufficient, the trigger signal is lost, or the actuator is abnormal, thus forming a fail-safe condensation access control.

[0132] Example 5: Flow restriction test and subsequent condensate feedback operation.

[0133] In another operating example, both the pre-stage condensate contamination index and the pre-defluorination penetration trend parameter meet the corresponding preset conditions, and the control unit 60 determines that the subsequent stage opening trigger condition has been formed. Since this subsequent stage opening trigger condition is the first time it has been formed in the current condensation stage, the control unit 60 does not directly put the subsequent low-temperature condensation unit 50 into a normal open state, but instead first allows the exhaust gas after pre-stage condensation to enter the subsequent low-temperature condensation unit 50 through the restricted flow path 80.

[0134] During the restricted flow period, the control unit 60 monitors the contamination index of the downstream condensate. When the contamination index of the downstream condensate meets the normal opening conditions, the control unit 60 allows the downstream low-temperature condensation unit 50 to enter the normal opening state; when the contamination index of the downstream condensate is within the observation range, the control unit 60 maintains the restricted flow state; when the contamination index of the downstream condensate worsens but has not yet reached the closing threshold, the control unit 60 reduces the exhaust gas flow rate entering the downstream low-temperature condensation unit 50; when the contamination index of the downstream condensate reaches or exceeds the closing threshold, the control unit 60 resets and closes the normally closed interlock valve 40 at the downstream inlet, and allows the exhaust gas to enter the emergency purification unit 100 or the non-condensation purification path.

[0135] By using the aforementioned flow-limiting test opening and subsequent condensate feedback control, the actual pollution risk of the subsequent low-temperature condensation process can be verified a second time before the subsequent low-temperature condensation unit 50 fully enters the normal open state, thereby further reducing the risk of corrosion and condensate pollution of the subsequent low-temperature condensation unit 50.

[0136] Example 6: Condensate contamination level feedback correction condition.

[0137] In another operating example, the condensate diversion unit 90 determines the condensate contamination level based on the upstream and downstream condensate contamination indicators. When the condensate contamination level is low, the control unit 60 can maintain the current downstream opening trigger condition, flow-limiting opening condition, and reset closing condition. When the condensate contamination level is medium, the control unit 60 can extend the flow-limiting opening observation time or reduce the initial exhaust gas treatment flow rate entering the downstream cryogenic condensation unit 50. When the condensate contamination level is high, the control unit 60 can increase the stringency of the upstream condensate contamination indicator judgment, reduce the allowable fluorine leakage load, reduce the allowable cumulative fluorine entry amount, or keep the downstream inlet normally closed interlock valve 40 closed.

[0138] When the condensate contamination level increases during multiple consecutive condensation stages, the control unit 60 can also issue a prompt signal to replace, regenerate, repair, or switch the emergency purification path of the anhydrous pre-defluorination unit 10. Therefore, the condensate contamination level is used not only for condensate destination management but also for the dynamic correction of subsequent condensation access conditions.

[0139] Example 7: Abnormal valve position feedback.

[0140] In another operating example, the control unit 60 determines that the downstream opening trigger condition has been formed and outputs an opening permission signal to the downstream inlet normally closed interlock valve 40. However, the valve position feedback component does not provide an open signal, or it provides feedback that the downstream inlet normally closed interlock valve 40 is in an intermediate abnormal state, an incompletely closed state, or a state where the valve position signal is lost.

[0141] In the above situation, the control unit 60 determines that the downstream inlet normally closed interlock valve 40 has not effectively entered the allowed flow state, or determines that the downstream opening trigger condition has not been effectively executed. The control unit 60 may cancel the opening permission signal, reset the downstream inlet normally closed interlock valve 40 to close, and allow the exhaust gas to enter the emergency purification unit 100 or the non-condensing purification path.

[0142] This control method can prevent the downstream cryogenic condensation unit 50 from being in an unverifiable open state due to jamming, actuator malfunction, or abnormal valve position feedback caused by the normally closed interlock valve 40 at the downstream inlet.

[0143] Example 8: Re-access condition after abnormal shutdown.

[0144] In another operating example, the normally closed interlock valve 40 at the downstream inlet is reset and closed due to abnormal pre-stage condensate contamination index, abnormal pre-defluorination penetration trend parameter, abnormal downstream condensate contamination index, invalid detection signal, lost trigger signal, or abnormal valve position feedback.

[0145] In this situation, the control unit 60 does not directly restore the normal open state of the downstream cryogenic condensation unit 50, but instead re-acquires the upstream condensate contamination index and pre-defluorination penetration trend parameters. After the upstream condensate contamination index and pre-defluorination penetration trend parameters both meet the corresponding preset conditions again and remain effective within the set stable detection window, the control unit 60 first allows the exhaust gas after upstream condensation to enter the downstream cryogenic condensation unit 50 through the flow-limiting path 80.

[0146] The control unit 60 only allows the downstream cryogenic condensation unit 50 to resume normal operation when the contamination index of the downstream condensate meets the normal opening conditions after the flow restriction is lifted, and the valve position feedback status of the normally closed interlock valve 40 at the downstream inlet is normal. This prevents the downstream cryogenic condensation unit 50 from directly resuming normal operation after the anomaly is resolved without re-verification.

[0147] In summary, the condensation access control in this embodiment of the invention is not a simple multi-stage condensation process control, nor is it solely based on condensate detection results for condensate diversion control. This invention obtains upstream condensate contamination indicators through the liquid phase verification unit 30 and pre-defluorination penetration trend parameters through the gas phase detection unit 70, using both as necessary conditions for releasing the closure constraint of the downstream inlet normally closed interlock valve 40.

[0148] When the current stage condensate contamination index fails to meet the corresponding preset conditions, the pre-defluorination penetration trend parameter fails to meet the corresponding preset conditions, effective detection conditions are missing, trigger signals are lost, valve position feedback is abnormal, or the downstream condensate contamination index is abnormal, the normally closed interlock valve 40 at the downstream inlet remains closed or is reset closed. Thus, this invention establishes a physical access constraint based on liquid phase verification and gas phase trend confirmation before the inlet of the downstream cryogenic condensation unit 50, which can reduce the risk of corrosion and condensate contamination caused by fluorinated acidic components entering the downstream cryogenic condensation unit 50 without access verification.

[0149] Furthermore, by limiting the flow path 80, a low-flow trial opening is achieved in the initial stage of the subsequent low-temperature condenser opening. The normal opening, maintaining the flow limit, reducing the flow, or closing state is controlled by feedback from the subsequent condensate contamination index. This can form a multi-level access control chain consisting of upstream liquid phase verification, pre-defluorination trend confirmation, valve position feedback confirmation, downstream flow limit verification, and downstream condensate feedback.

[0150] It should be noted that the specific detection indicators, detection thresholds, condensation temperatures, flow ranges, material types, detection cycles, stable detection windows, valve position feedback methods, and control logic in the above embodiments can all be adjusted according to the actual waste gas composition, treatment scale, corrosion resistance level of the downstream low-temperature condensation unit 50, condensate recovery quality requirements, and safe operation requirements. The above specific examples are only used to illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0151] According to the waste gas treatment device for retired lithium battery recycling and its condensation access control method provided in the embodiments of the present invention, the pre-stage condensate not only serves as a product of the pre-stage condensation process but also as a liquid-phase access verification medium before the opening of the subsequent low-temperature condensation stage; the pre-defluorination breakthrough trend parameter is used to determine whether the anhydrous pre-defluorination unit 10 has a breakthrough risk or operational abnormality; the normally closed interlock valve 40 at the subsequent inlet is used to remain closed before the subsequent opening trigger condition is formed, and to remain closed or reset closed under abnormal conditions. Therefore, the risk of equipment corrosion and condensate contamination caused by unverified fluorinated acidic components entering the subsequent low-temperature condensation process can be reduced.

[0152] Other components of the waste gas treatment device for recycling retired lithium batteries according to embodiments of the present invention, such as pipelines, fans, pumps, heat exchangers, condensate collection tanks, electrical control cabinets, and conventional testing instruments, can be conventionally configured according to actual working conditions by those skilled in the art, and will not be described in detail here.

[0153] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "some examples," "specific example," or "optional example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0154] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A condensation access control method for a waste gas treatment device for the recycling of retired lithium batteries, characterized in that, include: Anhydrous pre-fluorination is performed on the fluorine-containing organic waste gas generated during the recycling of retired lithium batteries. The fluorine-containing organic waste gas after anhydrous pre-defluorination is allowed to enter the pre-stage condensation process, and the normally closed interlock valve of the post-stage inlet, which is located upstream of the post-stage low-temperature condensation inlet, is kept closed before the post-stage opening trigger condition is formed, so as to restrict the waste gas after pre-stage condensation from entering the post-stage low-temperature condensation process before the post-stage opening trigger condition is formed. The forestage condensate generated during the forestage condensation process is introduced into the liquid phase verification unit, which is used to receive the forestage condensate and provide the location for detecting pollution indicators. The contamination indicators of the pre-stage condensate were detected, and the pre-defluorination breakthrough trend parameters were obtained; The subsequent opening triggering conditions include at least the following: the pollution index of the preceding condensate meets the corresponding preset conditions, and the pre-defluorination breakthrough trend parameter meets the corresponding preset conditions. When the downstream opening trigger condition is formed, the closing constraint of the normally closed interlock valve at the downstream inlet is released, allowing the exhaust gas after the upstream condensation to enter the downstream low-temperature condensation process. When the contamination index of the pre-stage condensate does not meet the corresponding preset conditions, or when the pre-defluorination penetration trend parameter does not meet the corresponding preset conditions, the subsequent stage opening trigger condition is not formed; wherein, when the normally closed interlock valve at the downstream inlet is not released from its closing constraint, the normally closed interlock valve at the downstream inlet is kept closed; when the normally closed interlock valve at the downstream inlet has been released from its closing constraint, the normally closed interlock valve at the downstream inlet is reset and closed.

2. The condensation access control method according to claim 1, characterized in that, The pollution indicators of the pre-stage condensate include at least one of the following: fluoride ion concentration, pH, conductivity, acidity, moisture content, turbidity, or organic component composition.

3. The condensation access control method according to claim 1, characterized in that, The pre-defluorination penetration trend parameters include at least one of the following: pre-defluorination outlet fluorine gas concentration, pre-defluorination outlet fluorine gas concentration change rate, pre-defluorination inlet and outlet fluorine gas concentration difference, pre-defluorination channel pressure difference, cumulative treatment time, or cumulative treatment air volume.

4. The condensation access control method according to claim 1, characterized in that, The fluorine leakage load is determined based on the concentration of fluorine-containing gas at the pre-defluorination outlet and the waste gas treatment flow rate, and the cumulative fluorine-containing amount entering the stage is determined based on the fluorine leakage load and the condensation stage operating time. The subsequent open trigger condition also includes at least one of the following: The fluorine leakage load shall not exceed the permissible fluorine leakage load; The cumulative fluoride content entering during the specified stage shall not exceed the allowable cumulative fluoride content entering.

5. The condensation access control method according to claim 1, characterized in that, During a condensation stage, when the subsequent stage opening trigger condition is first formed, the exhaust gas after the preceding stage condensation is first allowed to enter the subsequent low-temperature condensation through a flow-limiting path. The flow capacity of the flow-limiting path in the initial stage of the subsequent low-temperature condensation opening is lower than the flow capacity in the normal opening state of the subsequent low-temperature condensation.

6. The condensation access control method according to claim 5, characterized in that, After the exhaust gas from the pre-stage condensation enters the subsequent low-temperature condensation process through the flow-limiting path, the pollution index of the subsequent condensate is detected, and the subsequent low-temperature condensation process is controlled according to the pollution index of the subsequent condensate to enter a normal open state, maintain a flow-limited open state, reduce the exhaust gas treatment flow rate entering the subsequent low-temperature condensation process, or close the process.

7. The condensation access control method according to claim 1, characterized in that, If the pollution index of the current stage condensate exceeds the corresponding allowable pollution range, or the pre-defluorination penetration trend parameter exceeds the corresponding allowable access range, or if the pollution index of the subsequent stage condensate exceeds the corresponding allowable pollution range after detection, it is determined that the subsequent stage opening trigger condition has disappeared or the subsequent stage opening trigger condition has failed, the normally closed interlock valve at the inlet of the subsequent stage is reset and closed, and the exhaust gas enters the emergency purification process, or the exhaust gas enters the non-condensation purification path after being condensed by the previous stage.

8. A waste gas treatment device for recycling retired lithium batteries, characterized in that, include: An anhydrous pre-defluorination unit is used to perform anhydrous pre-defluorination on fluorine-containing organic waste gas generated during the recycling of retired lithium batteries. The pre-condensation unit is located downstream of the anhydrous pre-defluorination unit; The subsequent low-temperature condensing unit is located downstream of the preceding condensing unit; The liquid phase verification unit is connected to the condensate outlet of the pre-stage condensation unit and is used to receive the pre-stage condensate. The liquid phase verification unit includes at least one of the following: a pre-stage condensate verification chamber, a detection cell, a sampling passage, or an online detection section. A condensate contamination detection component is disposed in or connected to the liquid phase verification unit, and is used to detect contamination indicators of the upstream condensate. The gas phase detection unit is used to acquire pre-defluorination breakthrough trend parameters; The normally closed interlock valve at the downstream inlet is located upstream of the inlet of the downstream cryogenic condensation unit and remains closed when the downstream opening trigger condition is not met, so as to restrict the exhaust gas from entering the downstream cryogenic condensation unit. The reset component is connected to the normally closed interlock valve at the downstream inlet or integrated into the actuator of the normally closed interlock valve at the downstream inlet. It is used to reset the normally closed interlock valve at the downstream inlet to the closed state when the downstream opening trigger condition disappears, the upstream condensate contamination index does not meet the corresponding preset condition, the pre-defluorination penetration trend parameter does not meet the corresponding preset condition, or the trigger signal is lost. The control unit is connected to the condensate contamination detection component, the gas phase detection unit, and the normally closed interlock valve at the downstream inlet. The subsequent opening triggering conditions include at least the following: the contamination index of the preceding condensate meets the corresponding preset conditions, and the pre-defluorination penetration trend parameter meets the corresponding preset conditions. The control unit is used to release the closing constraint of the normally closed interlock valve at the inlet of the downstream stage when the downstream stage opening trigger condition is formed, and to determine that the downstream stage opening trigger condition has not been formed or has disappeared when the upstream condensate contamination index does not meet the corresponding preset condition or the pre-defluorination penetration trend parameter does not meet the corresponding preset condition, so that the normally closed interlock valve at the inlet of the downstream stage remains closed or is reset closed.

9. The waste gas treatment device for recycling retired lithium batteries according to claim 8, characterized in that, It also includes a flow restriction path, which is connected to the inlet of the downstream cryogenic condensing unit and is constrained by the downstream opening trigger condition. It is used to supply gas to the downstream cryogenic condensing unit at a flow rate lower than the processing flow rate of the downstream cryogenic condensing unit under normal opening conditions during the initial opening of the downstream cryogenic condensing unit after the downstream opening trigger condition is formed.

10. The waste gas treatment device for recycling retired lithium batteries according to claim 8, characterized in that, It also includes a condensate diversion unit, which is connected to at least one of the condensate outlet of the pre-stage condensation unit and the condensate outlet of the post-stage low-temperature condensation unit. The condensate diversion unit is used to determine the condensate contamination level based on the condensate contamination index of the pre-stage condensate and / or the condensate contamination index of the post-stage condensate, and to feed the condensate contamination level back to the control unit to correct the subsequent post-stage opening trigger condition, flow-limiting opening condition, or reset closing condition.

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