Catalytic oxidation-adsorption cooperative treatment method for lithium battery pyrolysis waste gas

Abstract

The invention discloses a lithium battery pyrolysis waste gas catalytic oxidation-adsorption cooperative treatment method, and relates to the technical field of lithium batteries, and the lithium battery pyrolysis waste gas catalytic oxidation-adsorption cooperative treatment method comprises the following operation steps: S1, pretreatment: treating lithium battery pyrolysis waste gas containing VOCs, acid gas and particulate matters by using a pretreatment device, and removing the particulate matters in the waste gas, the temperature of the waste gas is stably controlled at 200-250 DEG C; and S2, catalytic oxidation treatment: carrying out catalytic oxidation treatment on the pretreated waste gas through a catalytic oxidation reactor filled with a supported Pt / TiO2 catalyst. According to the catalytic oxidation-adsorption cooperative treatment method for the lithium battery pyrolysis waste gas, a complete and efficient waste gas treatment system is formed by integrating multiple link processes such as pretreatment, catalytic oxidation, adsorption, cooperative regulation and control, catalyst protection and tail gas recovery, and harmless treatment of the lithium battery pyrolysis waste gas can be achieved; the treatment efficiency, the operation economy and the environment-friendly compliance are considered.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and in particular to a method for the synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption. Background Technology

[0002] With the rapid development of the new energy vehicle and energy storage industries, the demand for lithium batteries continues to rise, leading to a continuous expansion of the scale of waste lithium battery recycling and processing. During the pyrolysis recycling of waste lithium batteries, complex waste gases containing large amounts of volatile organic compounds (VOCs), acidic gases (HF, HCl), and particulate matter are generated. These waste gas components are highly toxic and corrosive; direct emission would cause serious pollution to the atmospheric environment and threaten human health. Therefore, they must undergo strict purification treatment before being released.

[0003] Current lithium battery pyrolysis waste gas treatment technologies have many shortcomings: some processes only treat single pollutants, making it difficult to achieve synergistic and efficient removal of multiple pollutants, resulting in exhaust emissions failing to meet standards; traditional treatment methods lack coordinated control between catalysis and adsorption, easily leading to incomplete catalysis causing excessive consumption of adsorbents, or excessive adsorption capacity causing resource waste; in addition, the rapid deactivation rate of catalysts, short adsorbent saturation cycles, and complex regeneration processes not only increase operating costs but also reduce the continuity of the treatment process, failing to meet the needs of large-scale industrial treatment.

[0004] Therefore, it is necessary to propose a method for the synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for the synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption, in order to solve the problem that some processes only treat a single pollutant, making it difficult to achieve the synergistic and efficient removal of multiple pollutants, resulting in exhaust gas emissions failing to meet standards; and that traditional treatment methods lack linkage control between the catalytic and adsorption stages, which can easily lead to incomplete catalysis causing excessive consumption of adsorbent, or excessive adsorption capacity leading to resource waste.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for catalytic oxidation-adsorption synergistic treatment of lithium battery pyrolysis waste gas, comprising the following operational steps:

[0007] S1. Pretreatment: The pretreatment device is used to treat the lithium battery pyrolysis waste gas containing VOCs, acidic gases and particulate matter, remove the particulate matter in the waste gas, and stabilize the temperature of the waste gas at 200-250℃.

[0008] S2. Catalytic oxidation treatment: The pretreated waste gas is subjected to catalytic oxidation treatment through a catalytic oxidation reactor filled with a supported Pt / TiO2 catalyst for 10-15 seconds, while the VOCs concentration at the outlet of the catalytic oxidation reactor is monitored.

[0009] S3, Adsorption treatment stage: The waste gas after catalytic oxidation is adsorbed and treated using an adsorption reactor filled with CaO-Al2O3 composite adsorbent for 15-20 seconds, while the adsorption effect is monitored.

[0010] S4. Catalytic-Adsorption Synergistic Regulation: A gas composition and flow rate monitoring node is set between the catalytic oxidation reactor and the adsorption reactor, and a high-precision gas analyzer is installed at the monitoring node to detect the exhaust gas parameters.

[0011] S5. Catalyst deactivation early warning and in-situ protection: The reaction temperature of the catalytic oxidation reactor is monitored in real time by a temperature sensor, the occupancy of active sites on the surface of Pt / TiO2 catalyst is monitored in real time by a catalytic activity probe, and an early warning threshold is set. When the threshold is reached, N2 is introduced.

[0012] S6. Exhaust Gas Emission and Material Recovery: The exhaust gas after adsorption treatment is monitored by online monitoring equipment. If it meets the standards, it is discharged at high altitude; if it does not meet the standards, it is returned to the pretreatment stage. The activity of CaO-Al2O3 composite adsorbent and Pt / TiO2 catalyst is tested regularly, and the ineffective CaO-Al2O3 composite adsorbent and Pt / TiO2 catalyst are regenerated or replaced.

[0013] Preferably, in step S1, the pretreatment device is equipped with a filter assembly made of high-temperature resistant glass fiber filter material to intercept particles with a diameter greater than 10 μm.

[0014] Preferably, in S2, the supported Pt / TiO2 catalyst uses anatase TiO2 as the supporting matrix, and the Pt loading in the Pt / TiO2 catalyst is 0.5-1.0 wt%.

[0015] Preferably, in step S2, the VOCs concentration is monitored by an online monitoring device installed at the outlet of the catalytic oxidation reactor.

[0016] Preferably, in step S3, the mass ratio of CaO to Al2O3 in the CaO-Al2O3 composite adsorbent is 3:1, the particle size of the CaO-Al2O3 composite adsorbent is 2-5 mm, and the specific surface area is 150-200 m². 2 / g, and the CaO-Al2O3 composite adsorbent is uniformly distributed in the adsorption reactor.

[0017] Preferably, in step S3, the acidic gas in the waste gas undergoes an acid-base neutralization reaction with the CaO in the CaO-Al2O3 composite adsorbent, wherein the HF in the acidic gas reacts with CaO to form CaF2 precipitate, and the HCl in the acidic gas reacts with CaO to form CaCl2.

[0018] Preferably, in step S4, the waste gas parameters include residual VOCs concentration, acidic gas concentration, and gas flow rate. When the detected residual VOCs concentration and gas flow rate fluctuations reach preset thresholds, the inlet temperature of the catalytic oxidation reactor and the inlet flow rate of the adsorption reactor are adjusted, wherein the inlet temperature adjustment range is ±5℃, and the inlet flow rate adjustment range is ±0.5m. 3 / h.

[0019] Preferably, in step S4, multiple low-temperature microwave activation modules are spaced apart along the gas flow direction inside the adsorption reactor, with the activation temperature controlled at 120-150℃. When the removal efficiency of the CaO-Al2O3 composite adsorbent for acidic gases drops to the range of 95%-99%, the microwave activation module is activated. The generated microwave radiation keeps the internal pore structure of the CaO-Al2O3 composite adsorbent open and promotes the exposure of unreacted CaO active sites on the surface of the CaO-Al2O3 composite adsorbent.

[0020] Preferably, in step S5, the warning threshold is specifically defined as local reaction temperature fluctuation > 10°C and active site occupancy < 60%.

[0021] Preferably, in step S6, after the activity of the Pt / TiO2 catalyst is detected, when the activity of the Pt / TiO2 catalyst drops to less than 80% of the initial activity, the operation of the catalytic oxidation reactor is stopped, the Pt / TiO2 catalyst is taken out and regenerated by hot air purging. If the activity after regeneration still cannot meet the VOCs removal requirements, a new supported Pt / TiO2 catalyst is replaced.

[0022] The technical effects and advantages of this invention are as follows:

[0023] 1. This invention integrates multiple processes such as pretreatment, catalytic oxidation, adsorption, synergistic regulation, catalyst protection and tail gas recovery to form a complete and efficient waste gas treatment system. It can achieve the harmless treatment of lithium battery pyrolysis waste gas, taking into account treatment efficiency, operational economy and environmental compliance, and effectively solves the problems of incomplete pollutant removal, high resource consumption and poor process continuity in existing lithium battery pyrolysis waste gas treatment technologies.

[0024] 2. The lithium battery pyrolysis waste gas is treated by a pretreatment device. On the one hand, the filter components remove particulate matter from the waste gas, preventing particulate matter from polluting or clogging the Pt / TiO2 catalyst and CaO-Al2O3 composite adsorbent in the subsequent catalytic oxidation reactor and adsorption reactor, thus ensuring the stable operation of the core treatment unit. On the other hand, the heat exchanger adjusts the waste gas temperature to a suitable range, creating conditions for the full activity of the Pt / TiO2 catalyst in the subsequent catalytic oxidation reaction, thereby improving the overall process efficiency from the source.

[0025] 3. Relying on a catalytic oxidation reactor filled with a supported Pt / TiO2 catalyst, VOCs in waste gas can be efficiently converted into harmless CO2 and H2O. At the same time, with the help of an adsorption reactor filled with CaO-Al2O3 composite adsorbent, acidic gases in waste gas are specifically removed through acid-base neutralization reaction. It can also further adsorb trace pollutants that are not completely converted in the catalytic oxidation stage, realizing the staged and precise removal of multiple pollutants, greatly improving the comprehensiveness and thoroughness of waste gas purification, and ensuring that the content of various pollutants in the treated tail gas is effectively controlled.

[0026] 4. By setting up a catalytic-adsorption synergistic control link, a real-time monitoring and feedback mechanism is established between the catalytic oxidation reactor and the adsorption reactor. The central control system automatically adjusts the process parameters based on the detection data such as waste gas composition and flow rate, realizing dynamic matching between catalytic efficiency and adsorption load. This avoids excessive consumption of CaO-Al2O3 composite adsorbent due to incomplete catalysis, and also prevents resource waste caused by excessive adsorption capacity of CaO-Al2O3 composite adsorbent. At the same time, the low-temperature microwave activation module in the adsorption reactor can activate the activity of CaO-Al2O3 composite adsorbent in situ, maintaining adsorption efficiency without shutdown, significantly improving the continuity of the treatment process and reducing efficiency loss caused by equipment downtime.

[0027] 5. By embedding temperature sensors and catalytic activity probes in the catalytic oxidation reactor, a Pt / TiO2 catalyst deactivation early warning mechanism is constructed. This mechanism can promptly capture early deactivation signals of the Pt / TiO2 catalyst and simultaneously initiate in-situ protection measures such as inert gas supply and temperature regulation. This effectively inhibits the formation of carbon on the surface of the Pt / TiO2 catalyst, avoids local high temperatures from exacerbating Pt / TiO2 catalyst sintering, slows down the rate of activity decline of the Pt / TiO2 catalyst, extends the service life of the Pt / TiO2 catalyst, reduces the operating costs caused by frequent replacement of the Pt / TiO2 catalyst, and improves the economic efficiency and sustainability of the process.

[0028] 6. The exhaust gas after adsorption treatment is monitored by online monitoring equipment, and an exhaust gas emission control system is constructed in conjunction with the return pipeline to ensure that the exhaust gas that meets the standards is discharged in compliance with regulations through the exhaust stack. The exhaust gas that does not meet the standards can be returned to the pretreatment stage for retreatment, strictly ensuring that the exhaust gas emission meets environmental protection standards and avoiding environmental pollution. At the same time, the CaO-Al2O3 composite adsorbent that is saturated with adsorption is desorbed and regenerated or the by-products are recovered. The deactivated Pt / TiO2 catalyst is regenerated by hot air purging, realizing the recycling of CaO-Al2O3 composite adsorbent and Pt / TiO2 catalyst, improving resource utilization, reducing solid waste generation, and further reducing the environmental impact and operating costs of the process. Attached Figure Description

[0029] Figure 1 This is a flowchart of the method for catalytic oxidation-adsorption synergistic treatment of lithium battery pyrolysis waste gas according to the present invention. Detailed Implementation

[0030] This invention provides, for example Figure 1 The method described is a catalytic oxidation-adsorption synergistic treatment method for lithium battery pyrolysis waste gas. The method involves a pretreatment device to remove particulate matter from the waste gas and adjust its temperature to a suitable catalyst activity temperature. Then, a catalytic oxidation reactor filled with a supported Pt / TiO2 catalyst is used to convert VOCs in the waste gas into harmless substances through catalytic oxidation. Subsequently, the waste gas passes through an adsorption reactor filled with a CaO-Al2O3 composite adsorbent, where acidic gases are removed through acid-base neutralization. Finally, the exhaust gas, after passing testing and meeting standards, is discharged at high altitude. The CaO-Al2O3 composite adsorbent and the Pt / TiO2 catalyst can be regenerated or replaced to maintain treatment efficiency. This method achieves efficient, low-consumption, and harmless treatment of lithium battery pyrolysis waste gas without secondary pollution. The specific operation steps are as follows:

[0031] I. Preprocessing stage

[0032] Waste gas collection and pretreatment preparation: The waste gas from lithium battery pyrolysis is pretreated by a pretreatment device. The pretreatment device is equipped with a filter component made of high-temperature resistant glass fiber filter material, which can intercept particles larger than 10μm. The waste gas generated during the lithium battery pyrolysis process is collected first. This waste gas contains VOCs, acidic gases (HF, HCl) and particulate matter. Then, the waste gas is transported to the inlet of the pretreatment device through a sealed pipeline to ensure that the waste gas enters the pretreatment process stably.

[0033] Exhaust gas filtration and temperature regulation: Start the pretreatment device to make the collected exhaust gas flow through the filter component in the device, and use the filter component to remove particulate matter in the exhaust gas. After the particulate matter is removed, introduce the filtered exhaust gas into the heat exchanger configured with the pretreatment device, and stably control the temperature of the exhaust gas at 200 - 250 °C through the heat exchanger. This temperature is the suitable temperature for the Pt / TiO2 catalyst to exert its activity in the subsequent catalytic oxidation process, thus completing the pretreatment of the exhaust gas.

[0034] II. Catalytic oxidation treatment stage

[0035] Preparation of the catalytic oxidation reactor: Conduct catalytic oxidation treatment on the pretreated exhaust gas through the catalytic oxidation reactor. The catalytic oxidation reactor needs to be pre-loaded with a supported Pt / TiO2 catalyst. This supported Pt / TiO2 catalyst uses TiO2 as the supporting matrix. When loading, anatase TiO2 is selected, and its specific surface area can meet the requirements of the catalytic reaction for the number of active sites. At the same time, control the Pt loading amount in the Pt / TiO2 catalyst to be 0.5 - 1.0 wt%, ensuring that the Pt / TiO2 catalyst has high catalytic activity; after loading, check the sealing performance of the catalytic oxidation reactor to ensure no air leakage, avoiding the influence of exhaust gas leakage on the treatment efficiency and environmental protection effect. It can also be other alkaline adsorbents.

[0036] Catalytic oxidation treatment of exhaust gas: Continuously introduce the pretreated exhaust gas into the catalytic oxidation reactor filled with Pt / TiO2 catalyst through a transfer pump, which is configured with the catalytic oxidation reactor. Control the residence time of the exhaust gas in the catalytic oxidation reactor to be 10 - 15 s. Under the catalytic action of the Pt / TiO2 catalyst, the VOCs in the exhaust gas undergo a catalytic oxidation reaction to be converted into CO2 and H2O; at the same time, start the on-line monitoring device installed at the outlet of the catalytic oxidation reactor to continuously monitor the concentration of VOCs at the reactor outlet, ensuring that the VOCs removal efficiency is not less than 95%.

[0037] III. Adsorption treatment stage

[0038] Preparation of the adsorption reactor: Conduct adsorption treatment on the exhaust gas after catalytic oxidation through the adsorption reactor. The adsorption reactor is pre-filled with a CaO - Al2O3 composite adsorbent. During filling, control the mass ratio of CaO to Al2O3 in the CaO - Al2O3 composite adsorbent to be 3:1, and the particle size of the CaO - Al2O3 composite adsorbent is 2 - 5 mm, and its specific surface area is 150 - 200 m 2 / g, with good adsorption performance and structural stability. During the filling process, ensure that the CaO - Al2O3 composite adsorbent is evenly distributed in the adsorption reactor. After filling, check the connection sealing of the inlet and outlet pipes of the adsorption reactor to avoid exhaust gas leakage.

[0039] Waste gas adsorption treatment: The waste gas after catalytic oxidation is directly introduced into an adsorption reactor filled with CaO-Al2O3 composite adsorbent, and the residence time of the waste gas in the reactor is controlled to be 15-20 seconds. The CaO-Al2O3 composite adsorbent allows acidic gases (HF, HCl) in the waste gas to undergo an acid-base neutralization reaction with the CaO in the adsorbent. HF reacts with CaO to form CaF2 precipitate, and HCl reacts with CaO to form CaCl2. Simultaneously, the CaO-Al2O3 composite adsorbent further adsorbs trace pollutants that were not completely converted during the catalytic oxidation stage. During the treatment process, an online monitoring device installed at the outlet of the adsorption reactor monitors the adsorption effect to ensure that the removal efficiency of acidic gases is not less than 99%.

[0040] IV. Catalysis-Adsorption Synergistic Regulation Stage

[0041] Real-time feedback adjustment of synergistic parameters: A gas composition and flow rate monitoring node is set between the outlet of the catalytic oxidation reactor and the inlet of the adsorption reactor, and a high-precision gas analyzer is installed at this node. The high-precision gas analyzer monitors the parameters of the post-catalytic waste gas in real time, including residual VOCs concentration, acidic gas (HF, HCl) concentration, and gas flow rate. To achieve dynamic matching of "catalytic efficiency - adsorption load," a central control system is configured in conjunction with the monitoring node, the catalytic oxidation reactor, and the adsorption reactor, and the above-mentioned detection data is transmitted to this central control system in real time. The central control system has preset control thresholds, specifically residual VOCs concentration > 5% and gas flow rate fluctuation > 0.3m. 3 When the detected residual VOCs concentration and gas flow rate fluctuations reach preset thresholds, the system automatically adjusts the inlet temperature of the catalytic oxidation reactor and the inlet flow rate of the adsorption reactor. The inlet temperature adjustment range is ±5℃, and the inlet flow rate adjustment range is ±0.5m³ / h. 3 / h, in order to avoid excessive consumption of CaO-Al2O3 composite adsorbent due to incomplete catalysis, or waste of resources due to excess adsorption capacity of CaO-Al2O3 composite adsorbent.

[0042] In-situ activation of the adsorbent: Multiple low-temperature microwave activation modules are spaced along the gas flow direction inside the adsorption reactor. These modules are integrated with the reactor, and the activation temperature is controlled at 120-150℃, below the decomposition temperature of the CaO-Al2O3 composite adsorbent. When the online monitoring device installed at the reactor outlet detects that the removal efficiency of the CaO-Al2O3 composite adsorbent for acidic gases drops to 95%-99%, the central control system automatically activates the microwave activation module. The microwave radiation generated by the activation module keeps the internal pore structure of the CaO-Al2O3 composite adsorbent open and promotes the exposure of unreacted CaO active sites on the surface, extending the saturation period of the adsorbent by more than 30% compared to no activation treatment. Furthermore, the adsorption efficiency can be maintained without shutting down the reactor and removing the adsorbent, ensuring the continuity of the treatment process.

[0043] V. Catalyst Deactivation Early Warning and In-situ Protection Stage

[0044] Online catalyst activity early warning: Multiple sets of temperature sensors and catalytic activity probes are embedded inside the catalytic oxidation reactor. Both the temperature sensors and catalytic activity probes are integrated with the reactor for real-time monitoring of the Pt / TiO2 catalyst status. The temperature sensors monitor the reaction temperature in different areas of the reactor in real time, while the catalytic activity probes monitor the occupancy rate of active sites on the Pt / TiO2 catalyst surface in real time. An early warning threshold is set: a local reaction temperature fluctuation >10℃ and an active site occupancy rate <60%. When the monitored data reaches the threshold, the central control system immediately issues a Pt / TiO2 catalyst deactivation warning, simultaneously recording parameters such as exhaust gas composition and inlet gas flow rate at the time of the warning. This provides data support for subsequent Pt / TiO2 catalyst maintenance and avoids missing early deactivation signals.

[0045] In-situ catalyst protection: Upon receiving a deactivation warning from the central control system, the inert gas micro-feeding channel of the catalytic oxidation reactor is automatically activated. This channel is integrated with the catalytic oxidation reactor, and N2 is selected as the inert gas. Inert gas is introduced into the reactor at a volume ratio of 0.5-1% to inhibit carbon formation on the surface of the Pt / TiO2 catalyst. Simultaneously, the heat exchanger output is adjusted to reduce the inlet temperature of the catalytic oxidation reactor by 3-5°C, preventing localized high temperatures from exacerbating Pt / TiO2 catalyst sintering. Through these in-situ protection measures, the rate of activity decline of the Pt / TiO2 catalyst can be slowed down by more than 40%, extending the service life of the Pt / TiO2 catalyst and improving process economy and continuity.

[0046] VI. Exhaust Gas Emission and Material Recovery Stage

[0047] Exhaust Gas Detection and Emission: The exhaust gas after adsorption treatment is detected by online monitoring equipment. This equipment is integrated with the outlet and exhaust stack of the adsorption reactor to detect the concentrations of VOCs, HF, HCl, and particulate matter in the exhaust gas. If the detection results meet the "Integrated Emission Standard of Air Pollutants" (GB16297-1996) and relevant industry emission standards, the valve on the exhaust stack is opened. This valve is linked to the online monitoring equipment for control, allowing the exhaust gas to be discharged at high altitude through the exhaust stack. If the detection results fail to meet the standards, the exhaust gas is returned to the pretreatment stage for reprocessing via a return pipeline. This return pipeline connects the monitoring node before the exhaust stack to the inlet of the pretreatment device.

[0048] Adsorbent and catalyst recovery and treatment: The CaO-Al2O3 composite adsorbent in the adsorption reactor is sampled and tested periodically. When the adsorption efficiency of the CaO-Al2O3 composite adsorbent for acidic gases drops below 80%, it is determined that the CaO-Al2O3 composite adsorbent is saturated. The adsorption reactor is then stopped, and the saturated CaO-Al2O3 composite adsorbent is removed from the reactor. The removed CaO-Al2O3 composite adsorbent undergoes desorption regeneration treatment or is recycled as an industrial by-product. Simultaneously, the activity of the Pt / TiO2 catalyst in the catalytic oxidation reactor is tested periodically. When the Pt / TiO2 catalyst activity drops below 80% of its initial activity, the catalytic oxidation reactor is stopped, the Pt / TiO2 catalyst is removed, and it undergoes hot air purging regeneration treatment. If the activity after regeneration still cannot meet the VOCs removal requirements, a new supported Pt / TiO2 catalyst is replaced to ensure stable catalytic oxidation efficiency.

[0049] This invention integrates multiple processes, including pretreatment, catalytic oxidation, adsorption, synergistic regulation, catalyst protection, and tail gas recovery, to form a complete and efficient waste gas treatment system. This system enables the harmless treatment of lithium battery pyrolysis waste gas, balancing treatment efficiency, operational economy, and environmental compliance. It effectively solves problems such as incomplete pollutant removal, high resource consumption, and poor process continuity in existing lithium battery pyrolysis waste gas treatment technologies.

[0050] The pretreatment device treats the pyrolysis exhaust gas from lithium batteries. On the one hand, the filter components remove particulate matter from the exhaust gas, preventing it from polluting or clogging the Pt / TiO2 catalyst and CaO-Al2O3 composite adsorbent in the subsequent catalytic oxidation reactor and adsorption reactor, thus ensuring the stable operation of the core treatment unit. On the other hand, the heat exchanger adjusts the exhaust gas temperature to a suitable range, creating conditions for the full activity of the Pt / TiO2 catalyst in the subsequent catalytic oxidation reaction, thereby improving the overall process efficiency from the source.

[0051] Relying on a catalytic oxidation reactor filled with a supported Pt / TiO2 catalyst, VOCs in waste gas can be efficiently converted into harmless CO2 and H2O. At the same time, with the help of an adsorption reactor filled with CaO-Al2O3 composite adsorbent, acidic gases in waste gas are specifically removed through acid-base neutralization reaction. It can also further adsorb trace pollutants that are not completely converted in the catalytic oxidation stage, realizing the staged and precise removal of multiple pollutants, greatly improving the comprehensiveness and thoroughness of waste gas purification, and ensuring that the content of various pollutants in the treated exhaust gas is effectively controlled.

[0052] By setting up a catalytic-adsorption synergistic control link, a real-time monitoring and feedback mechanism is established between the catalytic oxidation reactor and the adsorption reactor. The central control system automatically adjusts the process parameters based on the detection data such as waste gas composition and flow rate, achieving dynamic matching between catalytic efficiency and adsorption load. This avoids excessive consumption of CaO-Al2O3 composite adsorbent due to incomplete catalysis, and also prevents resource waste caused by excess adsorption capacity of CaO-Al2O3 composite adsorbent. At the same time, the low-temperature microwave activation module in the adsorption reactor can activate the activity of CaO-Al2O3 composite adsorbent in situ, maintaining adsorption efficiency without shutdown, significantly improving the continuity of the treatment process and reducing efficiency loss caused by equipment downtime.

[0053] By embedding temperature sensors and catalytic activity probes within the catalytic oxidation reactor, a deactivation early warning mechanism for Pt / TiO2 catalysts is constructed. This mechanism can promptly capture early deactivation signals of the Pt / TiO2 catalysts and simultaneously initiate in-situ protection measures such as inert gas replenishment and temperature regulation. This effectively suppresses carbon formation on the surface of the Pt / TiO2 catalyst, prevents localized high temperatures from exacerbating Pt / TiO2 catalyst sintering, slows down the rate of activity decline of the Pt / TiO2 catalyst, extends the service life of the Pt / TiO2 catalyst, reduces operating costs caused by frequent Pt / TiO2 catalyst replacement, and improves the economics and sustainability of the process.

[0054] The exhaust gas after adsorption treatment is monitored by online monitoring equipment, and an exhaust gas emission control system is constructed in conjunction with the return pipeline to ensure that the exhaust gas that meets the standards is discharged in compliance with regulations through the exhaust stack. The exhaust gas that does not meet the standards can be returned to the pretreatment stage for retreatment, strictly ensuring that the exhaust gas emissions meet environmental protection standards and avoiding environmental pollution. At the same time, the CaO-Al2O3 composite adsorbent that is saturated with adsorption is desorbed and regenerated or the by-products are recovered, and the deactivated Pt / TiO2 catalyst is regenerated by hot air purging. This realizes the recycling of CaO-Al2O3 composite adsorbent and Pt / TiO2 catalyst, improves resource utilization, reduces solid waste generation, and further reduces the environmental impact and operating costs of the process.

[0055] In addition, the method for synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption includes the following embodiments:

[0056] Example 1

[0057] I. Preprocessing stage

[0058] The waste gas from lithium battery pyrolysis containing VOCs, acidic gases (HF, HCl) and particulate matter is collected and stably transported to the inlet of the pretreatment device through a sealed pipeline.

[0059] When the pretreatment device is turned on, the waste gas flows through the internal high-temperature resistant glass fiber filter assembly to remove particulate matter, and then is introduced into the matching heat exchanger to stabilize the temperature at 200℃, thus completing the waste gas pretreatment.

[0060] II. Catalytic Oxidation Treatment Stage

[0061] A supported Pt / TiO2 catalyst was loaded into the catalytic oxidation reactor, with the Pt loading controlled at 0.5 wt%. The support was anatase TiO2 with a specific surface area of ​​80 m². 2 / g, after filling, check the reactor's sealing performance to ensure there is no air leakage.

[0062] The pretreated waste gas is fed into the reactor via a matching pump, and the residence time of the waste gas is controlled at 10 seconds. The VOCs catalytic oxidation reaction is completed under the action of Pt / TiO2 catalyst. At the same time, the online monitoring device at the outlet is turned on to monitor the VOCs concentration in real time.

[0063] III. Adsorption Treatment Stage

[0064] The adsorption reactor was filled with CaO-Al2O3 composite adsorbent, with the mass ratio of CaO to Al2O3 controlled at 3:1. The CaO-Al2O3 composite adsorbent had a particle size of 2 mm and a specific surface area of ​​150 m². 2 / g, ensure even distribution during filling, and check the sealing of inlet and outlet pipes after filling.

[0065] The catalytically oxidized waste gas is introduced into the adsorption reactor, and the residence time is controlled at 15s. The CaO-Al2O3 composite adsorbent reacts with the acidic gas to form an acid-base neutralization reaction, in which HF is converted into CaF2 and HCl is converted into CaCl2. At the same time, trace pollutants are adsorbed. The online monitoring device at the outlet is turned on to monitor the adsorption effect.

[0066] IV. Catalysis-Adsorption Synergistic Regulation Stage

[0067] High-precision gas analyzers at monitoring nodes detect post-catalytic oxidation exhaust gas parameters in real time and transmit the data to the central control system. The system detects emissions when the residual VOCs concentration reaches 6% or the gas flow rate fluctuates by 0.4 m³ / h. 3 At a rate of / h, the system finely adjusts the inlet temperature of the catalytic oxidation reactor from 200℃ to -5℃, and the inlet flow rate of the adsorption reactor to 10m³ / h. 3 / h reference fine adjustment -0.5m 3 / h.

[0068] When the online monitoring device shows that the removal efficiency of the CaO-Al2O3 composite adsorbent for acidic gases drops to 95%, the central control system automatically starts the low-temperature microwave activation module in the adsorption reactor, with the activation temperature controlled at 120℃.

[0069] V. Catalyst Deactivation Early Warning and In-situ Protection Stage

[0070] Temperature sensors and catalytic activity probes inside the reactor monitor the state of the Pt / TiO2 catalyst in real time. When the local reaction temperature fluctuates by 11°C or the occupancy rate of active sites is 58%, the central control system issues a warning of Pt / TiO2 catalyst deactivation and records parameters such as exhaust gas composition and intake volume.

[0071] Upon receiving the warning, the inert gas supply channel is opened to introduce N2 at a volume ratio of 0.5%, and the pretreatment heat exchanger is adjusted to reduce the inlet temperature of the catalytic oxidation reactor by 3°C from 200°C.

[0072] VI. Exhaust Gas Emission and Material Recovery Stage

[0073] The online monitoring equipment detects the exhaust gas after adsorption. If it meets the "Integrated Emission Standard of Air Pollutants" GB16297-1996, the linkage valve is opened and the gas is discharged through the exhaust stack; if the VOCs concentration is 80 mg / m³... 3 (exceeding the standard limit of 60 mg / m²) 3 If the waste is not properly processed, it will be returned to the pretreatment stage via the return pipeline for reprocessing.

[0074] Regularly sample and test the CaO-Al2O3 composite adsorbent and Pt / TiO2 catalyst: When the adsorption efficiency of the CaO-Al2O3 composite adsorbent for acidic gases drops to 78%, remove it for desorption regeneration or recover it as a by-product; when the activity of the Pt / TiO2 catalyst drops to 75% of the initial activity, remove it for hot air purging regeneration. If the activity only recovers to 72% after regeneration, replace it with a new supported Pt / TiO2 catalyst.

[0075] In this embodiment, the VOCs removal efficiency at the outlet of the catalytic oxidation reactor reaches 95%, and the acid gas removal efficiency at the outlet of the adsorption reactor reaches 99%. The saturation period of the CaO-Al2O3 composite adsorbent is extended by 30% compared with the treatment without microwave activation, and the rate of activity decline of the Pt / TiO2 catalyst is slowed down by 40% compared with the treatment without in-situ protection measures.

[0076] Example 2

[0077] I. Preprocessing stage

[0078] The waste gas from lithium battery pyrolysis containing VOCs, acidic gases (HF, HCl) and particulate matter is collected and stably transported to the inlet of the pretreatment device through a sealed pipeline.

[0079] When the pretreatment device is turned on, the waste gas flows through the internal high-temperature resistant glass fiber filter assembly to remove particulate matter, and then is introduced into the matching heat exchanger to stabilize the temperature at 220℃, thus completing the waste gas pretreatment.

[0080] II. Catalytic Oxidation Treatment Stage

[0081] A supported Pt / TiO2 catalyst was loaded into the catalytic oxidation reactor, with the Pt loading controlled at 0.7 wt%. Anatase TiO2 was selected as the support, with a specific surface area of ​​95 m². 2 / g, after filling, check the reactor's sealing performance to ensure there is no air leakage.

[0082] The pretreated waste gas is fed into the reactor via a matching pump, and the residence time of the waste gas is controlled at 12 seconds. The VOCs catalytic oxidation reaction is completed under the action of Pt / TiO2 catalyst. At the same time, the online monitoring device at the outlet is turned on to monitor the VOCs concentration in real time.

[0083] III. Adsorption Treatment Stage

[0084] The adsorption reactor was filled with CaO-Al2O3 composite adsorbent, with the mass ratio of CaO to Al2O3 controlled at 3:1. The CaO-Al2O3 composite adsorbent had a particle size of 3 mm and a specific surface area of ​​170 m². 2 / g, ensure even distribution during filling, and check the sealing of inlet and outlet pipes after filling.

[0085] The catalytically oxidized waste gas is introduced into the adsorption reactor, and the residence time is controlled at 17s. The CaO-Al2O3 composite adsorbent reacts with the acidic gas to form an acid-base neutralization reaction, in which HF is converted into CaF2 and HCl is converted into CaCl2. At the same time, trace pollutants are adsorbed. The online monitoring device at the outlet is turned on to monitor the adsorption effect.

[0086] IV. Catalysis-Adsorption Synergistic Regulation Stage

[0087] The high-precision gas analyzer at the monitoring node detects the parameters of the post-catalytic oxidation exhaust gas in real time and transmits them to the central control system. The system detects emissions when the residual VOCs concentration is 7% or the gas flow rate fluctuates by 0.5 m³ / h. 3 At a rate of / h, the system finely adjusts the inlet temperature of the catalytic oxidation reactor by +3℃ from 220℃, and the inlet flow rate of the adsorption reactor is 12m³ / h. 3 / h base, fine-tuned by +0.2m 3 / h.

[0088] When the online monitoring device shows that the removal efficiency of the CaO-Al2O3 composite adsorbent for acidic gases drops to 97%, the central control system automatically starts the low-temperature microwave activation module in the adsorption reactor, with the activation temperature controlled at 130℃.

[0089] V. Catalyst Deactivation Early Warning and In-situ Protection Stage

[0090] Temperature sensors and catalytic activity probes inside the reactor monitor the state of the Pt / TiO2 catalyst in real time. When the local reaction temperature fluctuates by 12°C or the occupancy rate of active sites is 56%, the central control system issues a warning of Pt / TiO2 catalyst deactivation and records parameters such as exhaust gas composition and intake volume.

[0091] Upon receiving the warning, the inert gas supply channel is opened to introduce N2 at a volume ratio of 0.7%, and the pretreatment heat exchanger is adjusted to reduce the inlet temperature of the catalytic oxidation reactor by 4°C from 220°C.

[0092] VI. Exhaust Gas Emission and Material Recovery Stage

[0093] The online monitoring equipment detects the exhaust gas after adsorption. If it meets the "Integrated Emission Standard of Air Pollutants" GB16297-1996, the linkage valve is opened and the gas is discharged through the exhaust stack; if the HF concentration is 15 mg / m³... 3 (exceeding the standard limit by 10 mg / m²) 3 If the waste is not properly processed, it will be returned to the pretreatment stage via the return pipeline for reprocessing.

[0094] Regularly sample and test the CaO-Al2O3 composite adsorbent and Pt / TiO2 catalyst: When the adsorption efficiency of the CaO-Al2O3 composite adsorbent for acidic gases drops to 76%, remove it for desorption regeneration or recover it as a by-product; when the activity of the Pt / TiO2 catalyst drops to 73% of the initial activity, remove it for hot air purging regeneration. If the activity only recovers to 70% after regeneration, replace it with a new supported Pt / TiO2 catalyst.

[0095] In this embodiment, the VOCs removal efficiency at the outlet of the catalytic oxidation reactor reached 96.5%, and the acid gas removal efficiency at the outlet of the adsorption reactor reached 99.2%. The saturation period of the CaO-Al2O3 composite adsorbent was extended by 32% compared with the treatment without microwave activation, and the rate of activity decline of the Pt / TiO2 catalyst was slowed down by 42% compared with the treatment without in-situ protection measures.

[0096] Example 3

[0097] I. Preprocessing stage

[0098] The waste gas from lithium battery pyrolysis containing VOCs, acidic gases (HF, HCl) and particulate matter is collected and stably transported to the inlet of the pretreatment device through a sealed pipeline.

[0099] The pretreatment device is turned on. After the waste gas flows through the internal high-temperature resistant glass fiber filter material to remove particulate matter, it is introduced into the matching heat exchanger to stabilize the temperature at 250℃, thus completing the waste gas pretreatment.

[0100] II. Catalytic Oxidation Treatment Stage

[0101] A supported Pt / TiO2 catalyst was loaded into the catalytic oxidation reactor, with the Pt loading controlled at 1.0 wt%. The support was anatase TiO2 with a specific surface area of ​​120 m². 2 / g, after filling, check the reactor's sealing performance to ensure there is no air leakage.

[0102] The pretreated waste gas is fed into the reactor via a matching delivery pump, and the residence time of the waste gas is controlled at 15 seconds. The VOCs catalytic oxidation reaction is completed under the action of Pt / TiO2 catalyst. At the same time, the online monitoring device at the outlet is turned on to monitor the VOCs concentration in real time.

[0103] III. Adsorption Treatment Stage

[0104] The adsorption reactor was filled with CaO-Al2O3 composite adsorbent, with the mass ratio of CaO to Al2O3 controlled at 3:1. The CaO-Al2O3 composite adsorbent had a particle size of 5 mm and a specific surface area of ​​200 m². 2 / g, ensure even distribution during filling, and check the sealing of inlet and outlet pipes after filling.

[0105] The catalytically oxidized waste gas is introduced into the adsorption reactor, and the residence time is controlled at 20 seconds. The CaO-Al2O3 composite adsorbent reacts with the acidic gas to form an acid-base neutralization reaction, in which HF is converted into CaF2 and HCl is converted into CaCl2. At the same time, trace pollutants are adsorbed. The online monitoring device at the outlet is turned on to monitor the adsorption effect.

[0106] IV. Catalysis-Adsorption Synergistic Regulation Stage

[0107] The high-precision gas analyzer at the monitoring node detects the parameters of the post-catalytic oxidation exhaust gas in real time and transmits them to the central control system. This is triggered when the residual VOCs concentration reaches 10% or the gas flow rate fluctuates by 0.8 m / s. 3 At a rate of / h, the system finely adjusts the inlet temperature of the catalytic oxidation reactor by +5℃ from 250℃, and the inlet flow rate of the adsorption reactor is 18m³ / h. 3 / h base, fine-tuned by +0.5m 3 / h.

[0108] When the online monitoring device shows that the removal efficiency of the CaO-Al2O3 composite adsorbent for acidic gases drops to 99%, the central control system automatically starts the low-temperature microwave activation module in the adsorption reactor, with the activation temperature controlled at 150℃.

[0109] V. Catalyst Deactivation Early Warning and In-situ Protection Stage

[0110] Temperature sensors and catalytic activity probes inside the reactor monitor the state of the Pt / TiO2 catalyst in real time. When the local reaction temperature fluctuates by 15°C or the occupancy rate of active sites is 53%, the central control system issues an early warning of Pt / TiO2 catalyst deactivation and records parameters such as exhaust gas composition and intake volume.

[0111] Upon receiving the warning, the inert gas supply channel is opened to introduce N2 at a volume ratio of 1.0%, and the pretreatment heat exchanger is adjusted to reduce the inlet temperature of the catalytic oxidation reactor by 5°C from 250°C.

[0112] VI. Exhaust Gas Emission and Material Recovery Stage

[0113] The online monitoring equipment detects the exhaust gas after adsorption. If it meets the "Integrated Emission Standard of Air Pollutants" GB16297-1996, the linkage valve is opened and the gas is discharged through the exhaust stack; if the VOCs concentration is 90 mg / m³... 3 (exceeding the standard limit of 60 mg / m²) 3 If the waste is not properly processed, it will be returned to the pretreatment stage via the return pipeline for reprocessing.

[0114] Regularly sample and test the CaO-Al2O3 composite adsorbent and Pt / TiO2 catalyst: When the adsorption efficiency of the CaO-Al2O3 composite adsorbent for acidic gases drops to 73%, remove it for desorption regeneration or recover it as a by-product; when the activity of the Pt / TiO2 catalyst drops to 70% of the initial activity, remove it for hot air purging regeneration. If the activity only recovers to 67% after regeneration, replace it with a new supported Pt / TiO2 catalyst.

[0115] In this embodiment, the VOCs removal efficiency at the outlet of the catalytic oxidation reactor reached 98%, and the acid gas removal efficiency at the outlet of the adsorption reactor reached 99.5%. The saturation period of the CaO-Al2O3 composite adsorbent was extended by 35% compared with the treatment without microwave activation, and the rate of activity decline of the Pt / TiO2 catalyst was slowed down by 45% compared with the treatment without in-situ protection measures.

Claims

1. A method for synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption, characterized in that: The following steps are included: S1. Pretreatment: The pretreatment device is used to treat the lithium battery pyrolysis waste gas containing VOCs, acidic gases and particulate matter, remove the particulate matter in the waste gas, and stabilize the temperature of the waste gas at 200-250℃. S2. Catalytic oxidation treatment: The pretreated waste gas is catalytically oxidized in a catalytic oxidation reactor filled with a supported Pt / TiO2 catalyst for 10-15 seconds, while the VOCs concentration at the outlet of the catalytic oxidation reactor is monitored. S3, Adsorption treatment stage: The waste gas after catalytic oxidation is adsorbed and treated using an adsorption reactor filled with CaO-Al2O3 composite adsorbent for 15-20 seconds, while the adsorption effect is monitored. S4. Catalytic-Adsorption Synergistic Regulation: A gas composition and flow rate monitoring node is set between the catalytic oxidation reactor and the adsorption reactor, and a high-precision gas analyzer is installed at the monitoring node to detect the exhaust gas parameters. S5. Catalyst deactivation early warning and in-situ protection: The reaction temperature of the catalytic oxidation reactor is monitored in real time by a temperature sensor, the occupancy of active sites on the surface of Pt / TiO2 catalyst is monitored in real time by a catalytic activity probe, and an early warning threshold is set. When the threshold is reached, N2 is introduced. S6. Exhaust Gas Emission and Material Recovery: The exhaust gas after adsorption treatment is monitored by online monitoring equipment. If it meets the standards, it is discharged at high altitude; if it does not meet the standards, it is returned to the pretreatment stage. The activity of CaO-Al2O3 composite adsorbent and Pt / TiO2 catalyst is tested regularly, and the ineffective CaO-Al2O3 composite adsorbent and Pt / TiO2 catalyst are regenerated or replaced.

2. The method for synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption according to claim 1, characterized in that: In S1, the pretreatment device is equipped with a filter assembly made of high-temperature resistant glass fiber filter material to intercept particles with a diameter greater than 10μm.

3. The method for synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption according to claim 1, characterized in that: In S2, the supported Pt / TiO2 catalyst uses anatase TiO2 as the supporting matrix, and the Pt loading in the Pt / TiO2 catalyst is 0.5-1.0 wt%.

4. The method for synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption according to claim 1, characterized in that: In step S2, the concentration of VOCs is monitored by an online monitoring device installed at the outlet of the catalytic oxidation reactor.

5. The method for synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption according to claim 1, characterized in that: In S3, the mass ratio of CaO to Al2O3 in the CaO-Al2O3 composite adsorbent is 3:1, the particle size of the CaO-Al2O3 composite adsorbent is 2-5 mm, and the specific surface area is 150-200 m². 2 / g, and the CaO-Al2O3 composite adsorbent is uniformly distributed in the adsorption reactor.

6. The method for synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption according to claim 1, characterized in that: In step S3, the acidic gas in the exhaust gas undergoes an acid-base neutralization reaction with the CaO in the CaO-Al2O3 composite adsorbent. Specifically, the HF in the acidic gas reacts with CaO to form CaF2 precipitate, and the HCl in the acidic gas reacts with CaO to form CaCl2.

7. The method for synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption according to claim 1, characterized in that: In step S4, the waste gas parameters include residual VOCs concentration, acidic gas concentration, and gas flow rate. When the detected residual VOCs concentration and gas flow rate fluctuations reach preset thresholds, the inlet temperature of the catalytic oxidation reactor and the inlet flow rate of the adsorption reactor are adjusted. The inlet temperature adjustment range is ±5℃, and the inlet flow rate adjustment range is ±0.5m³. 3 / h.

8. The method for synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption according to claim 1, characterized in that: In step S4, multiple low-temperature microwave activation modules are spaced apart along the gas flow direction inside the adsorption reactor. The activation temperature is controlled at 120-150℃. When the removal efficiency of the CaO-Al2O3 composite adsorbent for acidic gases drops to the range of 95%-99%, the microwave activation module is activated. The generated microwave radiation keeps the internal pore structure of the CaO-Al2O3 composite adsorbent open and promotes the exposure of unreacted CaO active sites on the surface of the CaO-Al2O3 composite adsorbent.

9. The method for synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption according to claim 1, characterized in that: In S5, the warning threshold is specifically defined as local reaction temperature fluctuation > 10℃ and active site occupancy rate < 60%.

10. The method for synergistic treatment of lithium battery pyrolysis waste gas by catalytic oxidation and adsorption according to claim 1, characterized in that: In step S6, after the activity of the Pt / TiO2 catalyst is detected, when the activity of the Pt / TiO2 catalyst drops to less than 80% of the initial activity, the operation of the catalytic oxidation reactor is stopped, the Pt / TiO2 catalyst is taken out and regenerated by hot air purging. If the activity after regeneration still cannot meet the VOCs removal requirements, a new supported Pt / TiO2 catalyst is replaced.

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