Battery material one-burn process kiln oxygen-enriched waste gas recovery system and method

Abstract

The application discloses a battery material one-burning process kiln oxygen-enriched waste gas recovery system and method, relates to the technical field of industrial waste gas recovery, and comprises a first-stage cooling unit, a second-stage cooling unit, a high-concentration lye collecting unit, a primary filtration unit, a high-efficiency filtration unit, a high-pressure conveying unit, a molecular sieve decarburization unit, a metering and monitoring unit and a recycling pipeline. The first-stage cooling unit, the second-stage cooling unit and the high-concentration lye collecting unit are sequentially connected to form a cascade cooling and gas-liquid separation path, the high-temperature oxygen-enriched waste gas is gradually cooled and directly precipitates condensed water, no water washing tower or purification tower is arranged in the whole process, and the introduction of additional moisture load caused by wet scrubbing is avoided. Meanwhile, the high-pressure conveying unit is arranged between the primary filtration unit and the high-efficiency filtration unit, a single high-pressure fan is used to replace a compressor or a complex configuration of multiple induced draft fans, and the system structure is compact and occupies a small space.

Description

Technical Field

[0001] This invention relates to the field of industrial waste gas recovery technology, and in particular to an oxygen-enriched waste gas recovery system and method for the kiln in the first firing process of battery materials. Background Technology

[0002] The sintering process of lithium-ion battery cathode materials typically requires a high temperature of 300℃ to 400℃ in an oxygen-enriched atmosphere. The exhaust gas emitted from this process is high-temperature, oxygen-enriched waste gas, containing a large amount of unconsumed oxygen, carbon dioxide, dust, water vapor, and small amounts of alkaline substances. Direct emission not only results in a significant waste of oxygen resources and increased energy consumption for oxygen production, but also carries dust and carbon dioxide into the atmosphere. If the oxygen in this portion of the high-temperature, oxygen-enriched waste gas can be recovered and directly reused in the kiln, the load on purchased oxygen or on-site oxygen production can be significantly reduced, resulting in substantial energy-saving and cost-reduction benefits.

[0003] Currently, the fixed process of "induced draft fan → purification tower → compressor → dehydration → decarbonization" disclosed in patent CN202010708076.5, and the combined system of water washing tower, condenser, compressor and adsorption tower disclosed in patent CN202310308012.X, although they can achieve oxygen recovery, the system has wet scrubbing units such as water washing tower or purification tower, which not only increases the moisture load in the exhaust gas, leading to increased energy consumption for subsequent dehydration, but also generates a large amount of lithium-containing alkaline wastewater; in addition, the process is equipped with high-power compressors or multiple induced draft fans, making the system structure complex and occupying a large area. Summary of the Invention

[0004] This invention provides a kiln oxygen-enriched waste gas recovery system and method for the first firing process of battery materials. It can solve the problem in the prior art where wet scrubbing units such as water washing towers or purification towers are installed in the system, which not only increases the moisture load in the waste gas, leading to increased energy consumption for subsequent dehydration, but also generates a large amount of lithium-containing alkaline wastewater.

[0005] A kiln oxygen-enriched waste gas recovery system for a battery material firing process includes a first-stage cooling unit, a second-stage cooling unit, a high-concentration alkaline water collection unit, a primary filtration unit, a high-efficiency filtration unit, a high-pressure conveying unit, a molecular sieve decarbonization unit, a metering and monitoring unit, and a reuse pipeline. The first-stage cooling unit is connected to the kiln's exhaust port and is used to cool the high-temperature oxygen-enriched waste gas emitted from the kiln from a first temperature to a second temperature, precipitating a large amount of high-concentration alkaline water. The second-stage cooling unit is connected to the first-stage cooling unit and is used to cool the oxygen-enriched waste gas from the second temperature to a third temperature and further precipitate high-concentration alkaline water, achieving an oxygen dryness of 10-20%. The high-concentration alkaline water collection unit is located in the second stage. Downstream of the cooling unit, a high-concentration alkaline solution is collected and discharged; a primary filter unit is connected to the gas outlet of the high-concentration alkaline solution collection unit to filter particulate matter in the oxygen-enriched waste gas; a high-efficiency filter unit is connected after the primary filter unit to filter residual particulate matter in the oxygen-enriched waste gas; a high-pressure conveying unit is located between the primary filter unit and the high-efficiency filter unit; a molecular sieve decarbonization unit is connected to the high-pressure conveying unit; a metering and monitoring unit is located after the molecular sieve decarbonization unit and includes at least a flow meter and an oxygen analyzer to monitor the flow rate and oxygen concentration of the purified gas in real time; the inlet of the reuse pipeline is connected to the metering and monitoring unit, and the outlet is connected to the kiln.

[0006] The present invention provides an oxygen-enriched waste gas recovery system for a kiln in the first firing process of battery materials, which, compared with the prior art, has the following beneficial effects, but is not limited to: The oxygen-enriched waste gas recovery system for the kiln in the first firing process of battery materials forms a tiered cooling and gas-liquid separation path through a first-stage cooling unit, a second-stage cooling unit, and a high-concentration alkaline water collection unit connected in sequence. This system gradually cools the high-temperature oxygen-enriched waste gas and directly precipitates high-concentration alkaline water. The entire process does not require a water washing tower or purification tower, avoiding the additional moisture load introduced by wet washing and fundamentally eliminating the problems of increased energy consumption and the generation of large amounts of lithium-containing alkaline wastewater in subsequent dehydration. At the same time, by using a high-pressure conveying unit between the primary filter unit and the high-efficiency filter unit, a single high-pressure blower replaces the complex configuration of compressors or multiple induced draft fans. The system has a compact structure and small footprint, which greatly simplifies the process flow and equipment scale while realizing oxygen recovery.

[0007] Furthermore, the first-stage cooling unit is a stainless steel tube-fin radiator, and its cooling medium is industrial circulating water at 20℃~30℃; the second-stage cooling unit is a stainless steel tube-fin radiator, and its cooling medium is chilled water at 7℃~10℃.

[0008] Furthermore, the first temperature is 300℃~400℃, the second temperature is 60℃~80℃, and the third temperature is ≤50℃.

[0009] Furthermore, the high-concentration alkaline water collection unit includes a buffer tank, which is equipped with a liquid level monitoring device and a drain valve.

[0010] Furthermore, the primary filter unit and the high-efficiency filter unit are respectively equipped with a first differential pressure sensor and a second differential pressure sensor, which are used to monitor the clogging status of the corresponding filters in real time.

[0011] Furthermore, the high-pressure conveying unit is a high-pressure corrosion-resistant centrifugal fan, and its impeller surface is provided with a nano-coating.

[0012] Furthermore, the molecular sieve decarbonization unit is filled with a molecular sieve that selectively adsorbs carbon dioxide at room temperature and pressure, wherein the molecular sieve is a 13X type molecular sieve or a 5A type molecular sieve.

[0013] Furthermore, the metering and monitoring unit also includes a temperature sensor and a pressure sensor, and the oxygen analyzer is an online paramagnetic oxygen analyzer or a zirconia oxygen analyzer.

[0014] Furthermore, it also includes a control system, which includes a PLC controller and a human-machine interface. The PLC controller is connected to the first differential pressure sensor, the second differential pressure sensor, the liquid level monitoring device, the flow meter, and the oxygen analyzer, and controls the start-up, shutdown, and frequency of the high-pressure delivery unit.

[0015] A method for recovering oxygen-enriched waste gas from a kiln in the first firing process of battery materials, based on the aforementioned oxygen-enriched waste gas recovery system for a kiln in the first firing process of battery materials, includes the following steps: S1, cooling the oxygen-enriched waste gas discharged from the kiln at 300℃~400℃ sequentially to 60℃~80℃ with room temperature water, and then cooling it to ≤50℃ with chilled water, precipitating high-concentration alkaline water; S2, collecting and discharging the high-concentration alkaline water precipitated in S1 through a high-concentration alkaline water collection unit; S3, performing primary filtration on the oxygen-enriched waste gas treated in S2 through a primary filtration unit to remove particulate matter; S4, processing the waste gas after primary filtration in S3... Oxygen-enriched waste gas is pressurized and conveyed through a high-pressure conveying unit located after the primary filter unit and before the high-efficiency filter unit; S5, the oxygen-enriched waste gas pressurized and conveyed in S4 is subjected to terminal filtration through a high-efficiency filter unit located after the high-pressure conveying unit to intercept particulate matter that may be introduced by the high-pressure conveying unit; S6, the oxygen-enriched waste gas after terminal filtration in S5 is passed into a molecular sieve decarbonization unit to selectively adsorb carbon dioxide at normal temperature and pressure; S7, the flow rate and oxygen concentration of the gas treated in S6 are monitored in real time, and the purified gas with an oxygen concentration not lower than a set threshold is conveyed to the kiln inlet through a reuse pipeline. Attached Figure Description

[0016] Figure 1This is a system flow diagram of an oxygen-enriched waste gas recovery system for a kiln in the battery material firing process according to an embodiment of the present invention. Figure 2 This is a system flow diagram of the oxygen-enriched waste gas recovery system of the kiln in the battery material firing process according to another embodiment of the present invention. Figure 3 This is a flowchart illustrating a method for recovering oxygen-enriched waste gas from a kiln during the firing process of battery materials, according to an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures: 1. Kiln; 2. First-stage cooling unit; 3. Second-stage cooling unit; 4. High-concentration alkaline water collection unit; 5. Primary filtration unit; 6. High-efficiency filtration unit; 7. High-pressure conveying unit; 8. Molecular sieve decarbonization unit; 9. Metering and monitoring unit; 10. Reuse pipeline; 11. First differential pressure sensor; 12. Second differential pressure sensor; 13. Control system; 41. Buffer tank; 42. Liquid level monitoring device; 43. Drain valve; 81. First molecular sieve adsorption tower; 82. Second molecular sieve adsorption tower. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, specific embodiments of this application are described clearly and completely below with reference to the accompanying drawings. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments described in this application without creative effort will fall within the scope of protection of this application.

[0019] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the specification of this application is for the purpose of describing specific embodiments only and is not intended to limit this application; the terms "comprising," "including," "having," "containing," "comprise," etc., in the specification, claims, and accompanying drawings of this application are open-ended terms, indicating that a method comprises one or more steps, or an apparatus comprises one or more elements, but do not exclude the inclusion of other steps or elements. The terms "first," "second," etc., in the specification, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or primary / secondary relationship. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0020] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0021] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0022] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0023] Example 1: like Figure 1 As shown in the embodiment of the present invention, a kiln oxygen-enriched waste gas recovery system for a battery material firing process includes a first-stage cooling unit 2, a second-stage cooling unit 3, a high-concentration alkaline water collection unit 4, a primary filtration unit 5, a high-efficiency filtration unit 6, a high-pressure conveying unit 7, a molecular sieve decarbonization unit 8, a metering and monitoring unit 9, and a reuse pipeline 10. The first-stage cooling unit 2 is connected to the exhaust port of the kiln 1 and is used to cool the high-temperature oxygen-enriched waste gas emitted from the kiln from a first temperature to a second temperature, precipitating a large amount of high-concentration alkaline water. The second-stage cooling unit 3 is connected to the first-stage cooling unit 2 and is used to cool the oxygen-enriched waste gas from the second temperature to a third temperature and further precipitate high-concentration alkaline water, allowing the oxygen dryness to reach 10-20%. Collection unit 4 is located downstream of the second-stage cooling unit 3 and is used to collect and discharge high-concentration alkaline water; primary filter unit 5 is connected to the gas outlet of high-concentration alkaline water collection unit 4 and is used to filter particulate matter in oxygen-enriched waste gas; high-efficiency filter unit 6 is connected after primary filter unit 5 and is used to filter residual particulate matter in oxygen-enriched waste gas; high-pressure conveying unit 7 is located between primary filter unit 5 and high-efficiency filter unit 6; molecular sieve decarbonization unit 8 is connected to high-pressure conveying unit 7; metering and monitoring unit 9 is located after molecular sieve decarbonization unit 8 and includes at least a flow meter and an oxygen analyzer for real-time monitoring of the flow rate and oxygen concentration of the purified gas; the inlet end of the reuse pipeline 10 is connected to metering and monitoring unit 9, and the outlet end is connected to kiln 1.

[0024] In this embodiment, a tiered cooling and gas-liquid separation path is formed by sequentially connecting the first-stage cooling unit 2, the second-stage cooling unit 3, and the high-concentration alkaline water collection unit 4. The high-temperature oxygen-rich waste gas is cooled down step by step and high-concentration alkaline water is directly precipitated. No water washing tower or purification tower is required throughout the process, avoiding the introduction of additional water load by wet washing and fundamentally eliminating the problems of increased energy consumption and the generation of a large amount of lithium-containing alkaline wastewater in subsequent dehydration. At the same time, by using a high-pressure conveying unit 7 between the primary filter unit 5 and the high-efficiency filter unit 6, a single high-pressure blower replaces the complex configuration of compressors or multiple induced draft fans. The system has a compact structure and small footprint, which greatly simplifies the process flow and equipment scale while realizing oxygen recovery.

[0025] Specifically, through a two-stage cooling path consisting of the first-stage cooling unit 2 and the second-stage cooling unit 3, high-concentration alkaline water is precipitated through purely physical cooling throughout the process, without any water washing tower, thus eliminating the generation of lithium-containing wastewater at its source and eliminating the additional dehydration energy consumption caused by wet washing; the high-pressure conveying unit 7 uses a single high-pressure corrosion-resistant centrifugal fan instead of a compressor, and the fan is located between the primary filter unit 5 and the high-efficiency filter unit 6. The entire gas conveying path only requires one fan to overcome downstream resistance, greatly simplifying the system structure and significantly reducing the equipment size; after the gas exits from the molecular sieve decarbonization unit 8... The gas is directly fed into the metering and monitoring unit 9 for online monitoring. If the gas passes the test, it is directly transported to the kiln 1 via the reuse pipeline 10. If the gas fails the test, it is discharged through the venting pipeline. The control logic is simple and reliable, the number of devices is small, and the investment and maintenance costs are lower. The gas entering the fan is coarsely filtered and dust-removed by the high-pressure conveying unit 7 located after the primary filter unit 5. The impeller surface is also coated with a nano-coating to further reduce the generation of wear particles. The high-efficiency filter unit 6 downstream of the fan acts as a terminal security filter, which can intercept trace particles that may be introduced by the fan, ensuring the cleanliness of the gas finally reused in the kiln and effectively preventing the risk of metal contamination.

[0026] A single closed-loop circulation path is formed from the exhaust port to the inlet of kiln 1. After being discharged from kiln 1, the oxygen-enriched waste gas flows sequentially through each treatment unit and finally returns to kiln 1 via a reuse pipeline. The entire process is streamlined with no branching or bypassing, no intermediate storage tank buffers, and no material additions, forming a simple and continuous unidirectional process. The entire process uses purely physical methods to achieve gas cooling, filtration, dust removal, and pressurization, without introducing any chemical reactions, adding any detergents, or generating any secondary pollutants. All functions are accomplished collaboratively by purely electrical and mechanical structural components such as stainless steel heat exchangers, fiber filter media, centrifugal fans, sensors, and PLC controllers. The entire system has no compressors, vacuum pumps, or other complex moving equipment; the only moving part is a single high-pressure centrifugal fan, which reduces potential failure points at the source. The system is easy to start and stop, has extremely low maintenance and replacement costs, and can operate stably for a long time. It has extremely high reliability and adaptability to various operating conditions, making it particularly suitable for continuous and uninterrupted industrial production scenarios.

[0027] The primary filter unit 5 uses a bag or plate filter with a filtration accuracy of ≥0.5μm particles, effectively intercepting them. The air volume is designed to handle 800m³ / h to ensure sufficient margin. The filter housing is made of 304 stainless steel, and the filter media is made of polyester fiber or glass fiber. The high-efficiency filter unit 6 uses a high-efficiency plate filter with a filtration accuracy of ≥0.3μm particles, effectively intercepting them. The air volume is designed to handle 350m³ / h. The filter media is made of PTFE-coated glass fiber, which features low resistance and high filtration efficiency. The housing is made of 304 stainless steel.

[0028] like Figure 1 As shown, the first-stage cooling unit 2 is a stainless steel tube-fin radiator, and its cooling medium is industrial circulating water at 20℃~30℃; the second-stage cooling unit 3 is a stainless steel tube-fin radiator, and its cooling medium is chilled water at 7℃~10℃.

[0029] In this embodiment, by employing a stainless steel tube-fin radiator and introducing industrial circulating water at 20°C–30°C, the high-temperature, oxygen-rich waste gas discharged from the kiln at 300°C–400°C can be rapidly cooled to 60°C–80°C, achieving a significant initial temperature reduction. By employing a stainless steel tube-fin radiator and introducing chilled water at 7°C–10°C, the waste gas is further cooled from 60°C–80°C to ≤50°C. Through these two stages of cooling, a large amount of water vapor in the waste gas condenses and precipitates out due to the continuous breakdown of the dew point temperature. Simultaneously, some dust and alkaline substances entrained in the waste gas are separated along with the high-concentration alkaline solution, ensuring that the gas undergoes preliminary gas-liquid-solid three-phase separation before entering the subsequent filtration unit. By using a purely physical cooling and dehumidification path, the setting of a wet scrubbing tower is completely bypassed. Not only is there no need to introduce any scrubbing water into the system, thus fundamentally eliminating the generation of lithium-containing alkaline wastewater, but it also avoids the secondary dehydration energy consumption caused by the sharp increase in the moisture content of the exhaust gas after wet scrubbing. It achieves the same purification effect as wet scrubbing in a simpler and lower energy consumption way.

[0030] Specifically, the outlet temperature range for the first-stage cooling unit 2 is 60℃, 65℃, 70℃, 75℃, and 80℃, which can be adjusted according to seasonal changes and variations in circulating water temperature. The outlet temperature range for the second-stage cooling unit 3 is 35℃, 40℃, 45℃, and 50℃; the better the cooling effect, the lower the subsequent drying load.

[0031] In the combustion system, the condensate from the two-stage cooling units is highly alkaline and contains a large amount of soluble lithium salts. By setting up a high-concentration alkaline water collection unit 4 to centrally collect this highly alkaline water instead of directly discharging it, the condensate, which would otherwise be treated as wastewater, can be converted into lithium-containing raw material. Subsequent purification, concentration, and lithium precipitation processes extract high-purity lithium salt products for sale. This resource utilization path not only avoids the treatment costs and environmental risks of lithium-containing wastewater but also transforms the byproducts generated during waste gas recovery into new profit growth points, further improving the overall economic efficiency of the process.

[0032] like Figure 1 and Figure 2 As shown, the first temperature is 300℃~400℃, the second temperature is 60℃~80℃, and the third temperature is ≤50℃.

[0033] In this embodiment, the first temperature of 300℃~400℃ is the initial high-temperature range of the kiln exhaust. The first-stage cooling unit 2 cools it to a second temperature of 60℃~80℃, achieving a significant temperature reduction while causing some water vapor in the exhaust gas to initially condense. The second-stage cooling unit 3 further cools the exhaust gas from the second temperature of 60℃~80℃ to a third temperature of ≤50℃, breaking down the dew point of the remaining water vapor and causing it to precipitate in large quantities. Through the stepped cooling path, the water vapor in the high-temperature exhaust gas is gradually and fully condensed and separated in the two-stage cooling process, and gas-liquid separation can be completed without the need for spray washing water throughout the entire process.

[0034] like Figure 1 As shown, the high-concentration alkaline water collection unit 4 includes a buffer tank 41, and the buffer tank 41 is equipped with a liquid level monitoring device 42 and a drain valve 43.

[0035] In this embodiment, the buffer water tank 41 provides a centralized collection and temporary storage space for the high-concentration alkaline water precipitated from the two-stage cooling unit, so that the high-concentration alkaline water after gas-liquid separation can be collected in an orderly manner without flowing back into the airflow channel; the liquid level monitoring device 42 configured on the buffer water tank 41 can sense the liquid level in the tank in real time. When the liquid level reaches the preset upper limit, the linkage drain valve 43 automatically opens to discharge, avoiding the water tank overflowing and causing the high-concentration alkaline water to be re-entrained by the airflow, thus realizing the continuous and controlled discharge of high-concentration alkaline water.

[0036] like Figure 1 As shown, a first differential pressure sensor 11 and a second differential pressure sensor 12 are respectively provided on the primary filter unit 5 and the high-efficiency filter unit 6. The first differential pressure sensor 11 and the second differential pressure sensor 12 are used to monitor the clogging status of the corresponding filters in real time.

[0037] In this embodiment, the first differential pressure sensor 11 and the second differential pressure sensor 12 can respectively collect the pressure difference values ​​before and after the corresponding filter in real time, converting the degree of clogging of the filter media into a readable electrical signal. This allows maintenance personnel to accurately determine the dust accumulation status of the primary filter unit 5 and the high-efficiency filter unit 6 through the pressure difference values ​​without stopping the system for disassembly and inspection. When either pressure difference reaches a preset alarm threshold, the designated filter can be replaced or cleaned in a timely manner, avoiding increased system air resistance due to excessive clogging of a single-stage filter.

[0038] like Figure 1 As shown, the high-pressure conveying unit 7 is a high-pressure corrosion-resistant centrifugal fan, and its impeller surface is coated with a nano-coating.

[0039] In this embodiment, a single fan achieves full-process pressurization and delivery of gas, replacing the complex configuration of compressors or multiple induced draft fans in traditional processes. This results in a compact structure and significantly reduced footprint. The nano-coating on the impeller surface greatly reduces surface wear when the impeller comes into contact with airflow containing fine particles even after primary filtration, suppressing the shedding and generation of metal particles during fan operation at the source. Positioned after the primary filter unit 5 and before the high-efficiency filter unit 6, the fan effectively intercepts minute particles generated by impeller wear as a final safety filter when they enter the downstream high-efficiency filter unit 6 with the airflow. This ensures the high cleanliness of the reusable gas ultimately delivered to the kiln, fundamentally avoiding the risk of metal contamination of the cathode material product due to a pre-positioned fan or impeller wear.

[0040] Specifically, in existing technologies, the induced draft fan or compressor is usually placed before all filtration devices. High-temperature, dust-laden gas directly washes over the impeller, and metal particles generated by impeller wear enter the subsequent pipelines with the airflow and eventually return to the kiln. For high-nickel ternary cathode materials with extremely strict requirements on the content of metal foreign matter, there is a serious risk of product contamination. In this embodiment, the high-pressure conveying unit 7 is equipped with a primary filter unit 5 for coarse filtration protection at the front end and a high-efficiency filter unit 6 at the rear end as a terminal security filter. Even if the high-pressure conveying unit 7 generates a small amount of wear particles during long-term operation, they will be effectively intercepted by the downstream high-efficiency filter unit 6 and will not be able to enter the molecular sieve decarbonization unit 8 and the reuse pipeline 10.

[0041] like Figure 1 As shown, the molecular sieve decarbonization unit 8 is filled with a molecular sieve that selectively adsorbs carbon dioxide at room temperature and pressure. The molecular sieve is either a 13X type molecular sieve or a 5A type molecular sieve.

[0042] In this embodiment, the molecular sieve decarbonization unit 8 is filled with 13X or 5A type molecular sieves. Utilizing the unique microporous structure and polar surface of these molecular sieves, highly selective physical adsorption of carbon dioxide can be achieved under ambient temperature and pressure conditions, while almost no oxygen is adsorbed. This avoids the complex operations such as heating and vacuuming required by traditional temperature-swing-pressure adsorption decarbonization processes. It eliminates the need for compressors, vacuum pumps, and corresponding switching valve groups, significantly simplifying the equipment configuration and reducing operating energy consumption. Simultaneously, the mild operating conditions at ambient temperature and pressure extend the service life of the molecular sieves, reducing regeneration frequency and maintenance costs.

[0043] like Figure 1 As shown, the metering and monitoring unit 9 also includes a temperature sensor and a pressure sensor, and the oxygen analyzer is an online paramagnetic oxygen analyzer or a zirconia oxygen analyzer.

[0044] In this embodiment, by adding temperature and pressure sensors, four key parameters of the purified gas—temperature, pressure, flow rate, and oxygen concentration—can be simultaneously collected, enabling multi-dimensional real-time online monitoring. The introduction of temperature and pressure sensors allows for condition compensation correction of the flow meter and oxygen analyzer measurements, eliminating measurement deviations caused by gas temperature fluctuations or pressure changes. The online paramagnetic oxygen analyzer or zirconia oxygen analyzer features fast response, high measurement accuracy, and wide range coverage, accurately determining whether the gas oxygen concentration has reached the reuse threshold within seconds. The switching valve action of the control system provides reliable data, ensuring that only gas with the required oxygen concentration is returned to the kiln 1 via the reuse pipeline 10, while unqualified gas is promptly switched off and discharged, ensuring the stability of the kiln sintering atmosphere. The reuse pipeline 10 is equipped with a pneumatic or electric switching valve. When the oxygen analyzer detects that the oxygen concentration is lower than the set threshold (e.g., 95%), the switching valve will automatically switch the unqualified gas to the vent pipeline for discharge and issue an audible and visual alarm signal.

[0045] like Figure 1 As shown, it also includes a control system 13, which includes a PLC controller and a human-machine interface. The PLC controller is connected to the first differential pressure sensor 11, the second differential pressure sensor 12, the liquid level monitoring device 42, the flow meter and the oxygen analyzer, and controls the start-up and shutdown and frequency of the high-pressure delivery unit 7.

[0046] In this embodiment, the PLC controller centrally processes multiple signals collected by the first differential pressure sensor 11, the second differential pressure sensor 12, the liquid level monitoring device 42, the flow meter, and the oxygen analyzer, including the filter clogging status, high-concentration alkaline water level, purified gas flow rate, and oxygen concentration. The system's operating status is then centrally displayed and parameters are set via a human-machine interface. Based on preset logic, the PLC controller automatically adjusts the start / stop and operating frequency of the high-pressure conveying unit 7 to match the fan output with downstream gas demand and the actual resistance of the filter, thus avoiding energy waste caused by fixed-frequency operation.

[0047] The control system 13 can use a Siemens S7-1200 series PLC as the central controller and be equipped with a Siemens 10-inch touch screen as the human-machine interface.

[0048] A method for recovering oxygen-enriched waste gas from a kiln in the first firing process of battery materials, based on an oxygen-enriched waste gas recovery system for a kiln in the first firing process of battery materials, includes the following steps: S1, cooling the oxygen-enriched waste gas discharged from kiln 1 at 300℃~400℃ sequentially to 60℃~80℃ with room temperature water, and then cooling it to ≤50℃ with chilled water, precipitating high-concentration alkaline water; S2, collecting and discharging the high-concentration alkaline water precipitated in S1 through a high-concentration alkaline water collection unit 4; S3, performing primary filtration on the oxygen-enriched waste gas treated in S2 through a primary filtration unit 5 to remove particulate matter; S4, processing the oxygen-enriched waste gas after primary filtration in S3... The gas is pressurized and conveyed through a high-pressure conveying unit 7 located after the primary filter unit 5 and before the high-efficiency filter unit 6; S5, the oxygen-enriched waste gas after S4 pressurization and conveying is filtered at the terminal by the high-efficiency filter unit 6 located after the high-pressure conveying unit 7 to intercept particulate matter that may be introduced by the high-pressure conveying unit 7; S6, the oxygen-enriched waste gas after terminal filtration in S5 is passed into the molecular sieve decarbonization unit 8, where carbon dioxide is selectively adsorbed at normal temperature and pressure; S7, the flow rate and oxygen concentration of the gas after S6 treatment are monitored in real time, and the purified gas with an oxygen concentration not lower than the set threshold is conveyed to the inlet of the kiln 1 through the reuse pipeline 10.

[0049] In this embodiment, the oxygen-rich waste gas discharged from kiln 1 at 300℃~400℃ is first cooled to 60℃~80℃ by ambient water, and then further cooled to ≤50℃ by chilled water, resulting in the precipitation of high-concentration alkaline water. This two-stage cooling method replaces wet washing, achieving preliminary separation of the gas, liquid, and solid phases under waterless washing conditions. This eliminates the generation of lithium-containing alkaline wastewater and the energy consumption for secondary dehydration. The high-concentration alkaline water is collected and discharged centrally by the high-concentration alkaline water collection unit 4, preventing liquid water from being carried downstream by the airflow and ensuring the treatment efficiency of subsequent filtration units. The primary filter unit 5 removes larger particles from the waste gas, ensuring that the gas entering the high-pressure conveying unit 7 is in a relatively clean state, reducing the wear of the fan impeller. The high-pressure conveying unit 7 is placed after the primary filter unit 5 and before the high-efficiency filter unit 6, achieving this with a single fan. The pressurized gas delivery eliminates the need for compressors or multiple induced draft fans, and the fans come into contact with coarsely filtered gas, which helps extend equipment life. The pressurized gas undergoes final filtration through the high-efficiency filtration unit 6, effectively intercepting trace abrasive particles or external debris that may be introduced during the operation of the high-pressure delivery unit 7, forming a final clean guarantee for the recycled gas. The final filtered gas is then passed into the molecular sieve decarbonization unit 8, where carbon dioxide is selectively adsorbed by the molecular sieve under normal temperature and pressure conditions. No heating or vacuuming is required throughout the process, resulting in low energy consumption and simple operation. The flow rate and oxygen concentration of the treated gas are monitored in real time, and only gas with an oxygen concentration reaching the set threshold is delivered to the inlet of the kiln 1 through the recycling pipeline 10, ensuring stable and controllable recycled gas quality and guaranteeing the consistency of the atmosphere and product yield in the cathode material sintering process.

[0050] Example 2: like Figure 3 As shown, the main difference between this embodiment and Embodiment 1 is that the molecular sieve decarbonization unit 8 adopts a parallel dual-tower structure, including a first molecular sieve adsorption tower 81 and a second molecular sieve adsorption tower 82, i.e., two identical molecular sieve adsorption towers are set up. When the first molecular sieve adsorption tower 81 is in adsorption operation, the second molecular sieve adsorption tower 82 is regenerated or in standby mode; after working for a period of time (e.g., 8 hours), the adsorption is switched to the second molecular sieve adsorption tower 82, and the first molecular sieve adsorption tower 81 is regenerated by introducing dry air or nitrogen and heating. This dual-tower switching design can achieve continuous decarbonization treatment without affecting the continuous production of the kiln.

[0051] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A kiln oxygen-enriched waste gas recovery system for a battery material firing process, characterized in that, include: The first-stage cooling unit (2) is connected to the exhaust port of the kiln (1) and is used to cool the high-temperature oxygen-rich waste gas discharged from the kiln from the first temperature to the second temperature, and precipitate a large amount of high-concentration alkaline water. The second-stage cooling unit (3) is connected to the first-stage cooling unit (2) and is used to cool the oxygen-rich waste gas from the second temperature to the third temperature and further precipitate high-concentration alkaline water, so that the oxygen dryness reaches 10-20%. A high-concentration alkaline water collection unit (4) is located downstream of the second-stage cooling unit (3) and is used to collect and discharge the high-concentration alkaline water. The primary filter unit (5) is connected to the gas outlet of the high-concentration alkaline water collection unit (4) and is used to filter particulate matter in the oxygen-rich waste gas. A high-efficiency filter unit (6) is connected after the primary filter unit (5) and is used to filter residual particulate matter in oxygen-rich exhaust gas. A high-pressure delivery unit (7) is disposed between the primary filter unit (5) and the high-efficiency filter unit (6); The molecular sieve decarbonization unit (8) is connected to the high-pressure conveying unit (7); A metering and monitoring unit (9) is set after the molecular sieve decarbonization unit (8) and includes at least a flow meter and an oxygen analyzer for real-time monitoring of the flow rate and oxygen concentration of the purified gas. The reuse pipeline (10) has its inlet end connected to the metering and monitoring unit (9) and its outlet end connected to the kiln (1).

2. The oxygen-enriched waste gas recovery system for the kiln in the battery material firing process as described in claim 1, characterized in that, The first stage cooling unit (2) is a stainless steel tube-fin radiator, and its cooling medium is industrial circulating water at 20℃~30℃; the second stage cooling unit (3) is a stainless steel tube-fin radiator, and its cooling medium is chilled water at 7℃~10℃.

3. The oxygen-enriched waste gas recovery system for the kiln in the battery material firing process as described in claim 1, characterized in that, The first temperature is 300℃~400℃, the second temperature is 60℃~80℃, and the third temperature is ≤50℃.

4. The oxygen-enriched waste gas recovery system for the kiln in the battery material firing process as described in claim 1, characterized in that, The high-concentration alkaline water collection unit (4) includes a buffer tank (41), and the buffer tank (41) is equipped with a liquid level monitoring device (42) and a drain valve (43).

5. The oxygen-enriched waste gas recovery system for the kiln in the battery material firing process as described in claim 1, characterized in that, The primary filter unit (5) and the high-efficiency filter unit (6) are respectively equipped with a first differential pressure sensor (11) and a second differential pressure sensor (12). The first differential pressure sensor (11) and the second differential pressure sensor (12) are used to monitor the clogging status of the corresponding filters in real time.

6. The oxygen-enriched waste gas recovery system for the kiln in the battery material firing process as described in claim 1, characterized in that, The high-pressure conveying unit (7) is a high-pressure corrosion-resistant centrifugal fan, and its impeller surface is provided with a nano-coating.

7. The oxygen-enriched waste gas recovery system for the kiln in the battery material firing process as described in claim 1, characterized in that, The molecular sieve decarbonization unit (8) is filled with a molecular sieve that selectively adsorbs carbon dioxide at room temperature and pressure. The molecular sieve is a 13X type molecular sieve or a 5A type molecular sieve.

8. The oxygen-enriched waste gas recovery system for the kiln in the battery material firing process as described in claim 1, characterized in that, The metering and monitoring unit (9) also includes a temperature sensor and a pressure sensor, and the oxygen analyzer is an online paramagnetic oxygen analyzer or a zirconia oxygen analyzer.

9. The oxygen-enriched waste gas recovery system for the kiln in the battery material firing process as described in claim 1, characterized in that, It also includes a control system (13), which includes a PLC controller and a human-machine interface. The PLC controller is connected to the first differential pressure sensor (11), the second differential pressure sensor (12), the liquid level monitoring device (42), the flow meter and the oxygen analyzer respectively, and controls the start and stop and frequency of the high-pressure delivery unit (7).

10. A method for recovering oxygen-enriched waste gas from a kiln during the firing process of battery materials, characterized in that, The system for recovering oxygen-enriched waste gas from a kiln in the firing process of battery materials as described in any one of claims 1-9 includes the following steps: S1. The oxygen-rich waste gas discharged from the kiln (1) at 300℃~400℃ is cooled to 60℃~80℃ by ambient temperature water, and then cooled to ≤50℃ by chilled water, and high-concentration alkaline water is released. S2, collect and discharge the high-concentration alkaline water precipitated in S1 through the high-concentration alkaline water collection unit (4); S3. The oxygen-rich waste gas after S2 treatment is filtered through the primary filter unit (5) to remove particulate matter. S4. The oxygen-rich exhaust gas after the primary filter in S3 is pressurized and transported through a high-pressure conveying unit (7) located after the primary filter unit (5) and before the high-efficiency filter unit (6). S5. The oxygen-rich exhaust gas after S4 pressurization and transportation is filtered at the terminal through the high-efficiency filter unit (6) set after the high-pressure transportation unit (7) to intercept particulate matter that may be introduced by the high-pressure transportation unit (7). S6. The oxygen-rich waste gas filtered by the S5 terminal is passed into the molecular sieve decarbonization unit (8) to selectively adsorb carbon dioxide at normal temperature and pressure. S7. Monitor the flow rate and oxygen concentration of the gas after S6 treatment in real time, and transport the purified gas with an oxygen concentration not lower than the set threshold to the inlet of the kiln (1) through the reuse pipeline (10).

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