Metallic lithium dehumidification storage method and device
By constructing a two-stage circulating temperature and humidity control system, the humidity inside the buffer cabinet is monitored and adjusted in real time, solving the problem of lithium metal oxidation in high humidity environments, achieving efficient dehumidification, and ensuring the safety and refining quality of lithium metal.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CNNC JIANZHONG NUCLEAR FUEL
- Filing Date
- 2024-12-10
- Publication Date
- 2026-06-12
AI Technical Summary
Lithium metal is easily oxidized in high humidity environments, forming a nitrogen oxide film and lithium hydroxide impurities, which increases the risk of fire, affects refining quality, and existing caching methods cannot effectively control humidity.
By employing intelligent control technology, combined with temperature and humidity sensors, semiconductor dehumidifiers, and silica gel drying and regeneration units, a two-stage circulating temperature and humidity control system is constructed to monitor and adjust the humidity inside the buffer cabinet in real time, thereby achieving precise dehumidification.
The relative humidity in the buffer space will be reduced from 80% to below 40% within 4 hours and to below 30% ± 3% within 2 hours, meeting the daily storage requirements of lithium metal, avoiding oxidation, and ensuring safety and quality.
Smart Images
Figure CN122186558A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium metal dehumidification and buffering technology, and in particular to a method and apparatus for lithium metal dehumidification and buffering. Background Technology
[0002] The lithium metal produced in the electrolysis process is cast into lithium ingots by each production shift and temporarily stored in stainless steel transfer drums on site. Due to its highly reactive chemical properties, there is no effective dehumidification and buffering method. It is easy to react with nitrogen, oxygen and water vapor in the air. When the humidity in the air is high, lithium metal is also easy to react with water vapor in the air at room temperature to generate lithium hydroxide impurities. At the same time, under high humidity conditions, the reaction rate of nitrogen in the air with lithium metal is accelerated to generate lithium nitride impurities.
[0003] Currently, the main problems with lithium metal caches are:
[0004] 1. When the air humidity reaches 80%, a layer of nitrogen oxide film will quickly form on the surface of lithium metal, which will have an adverse effect on the quality of the product in the next refining and purification process of lithium metal.
[0005] 2. Some electrolyte remains on the surface of the lithium metal ingots produced by electrolysis. This electrolyte is highly susceptible to absorbing water in humid air, which increases the safety risk of lithium metal ignition during the refining process and also has an adverse effect on the quality of refined lithium.
[0006] Because the relative humidity of the ambient environment is typically above 60%, lithium metal oxidizes rapidly under such conditions. After three working days, noticeable white oxide spots appeared on the surface of the lithium metal when it was packaged and stored. Experiments showed that lithium metal exhibited surface oxidation when stored in an environment with a relative humidity of 60%–70% for three working days, but showed no apparent oxidation when stored in an environment with a relative humidity of 40% for three working days. This indicates that lithium metal can be temporarily stored in an environment with a relative humidity of ≤40% for another three working days, meeting the current requirements for the interval between lithium metal transfers. Therefore, to slow down the oxidation rate of lithium metal, a sealed buffering method with dehumidification and drying functions must be adopted. Summary of the Invention
[0007] The technical problem to be solved by the present invention is to provide a method and device for dehumidifying and buffering lithium metal, which adopts intelligent control technology to collect temperature and humidity data in real time, achieves precise control, and meets the current requirements for the time interval of lithium metal produced by molten salt electrolysis.
[0008] This invention provides a lithium metal dehumidification and buffer device, comprising:
[0009] The buffer cabinet is equipped with several temperature, humidity, and pressure sensors.
[0010] The air outlet of the buffer cabinet is connected in sequence to a semiconductor dehumidifier and a silica gel drying and regeneration unit via pipes;
[0011] The air outlet of the silica gel drying and regeneration unit is connected to the air inlet of the buffer cabinet;
[0012] A first electrically operated valve and an air filter are installed between the buffer cabinet and the semiconductor dehumidifier;
[0013] An exhaust fan is installed between the semiconductor dehumidifier and the silica gel drying and regeneration unit;
[0014] Temperature and humidity sensors are installed in semiconductor dehumidifiers and silica gel drying and regeneration units.
[0015] The controller receives signals from various temperature, humidity, and pressure sensors in real time and controls the operation of the semiconductor dehumidifier and silica gel drying and regeneration unit.
[0016] In one specific embodiment of the present invention, the silica gel drying and regeneration unit includes: two silica gel drying and regeneration devices and a heater connected in parallel;
[0017] Each silica gel drying and regeneration unit is equipped with a throttle valve in front of it and an electric three-way valve and a temperature and humidity sensor at its rear end.
[0018] A second electric switch valve is installed before the heater, and an electric three-way valve is installed at its rear end;
[0019] A temperature and humidity sensor is installed before the silica gel drying and regeneration device.
[0020] In one specific embodiment of the present invention, the semiconductor dehumidifier and the silica gel drying and regeneration unit are respectively installed inside the cabinet of the buffer cabinet.
[0021] In one specific embodiment of the present invention, a display screen is also included to simultaneously display temperature, humidity, and pressure data inside the buffer cabinet.
[0022] In one specific embodiment of the present invention, the silica gel drying and regeneration device is externally wrapped with an armored electric heating tape.
[0023] This invention provides a method for dehumidifying and buffering lithium metal, comprising the following steps:
[0024] Real-time monitoring of humidity, temperature, and pressure within the cache cabinet;
[0025] When any humidity sensor in the buffer cabinet detects that the air humidity inside the cabinet is ≥40%, the semiconductor dehumidifier and silica gel drying and regeneration unit are activated. The humid air enters the semiconductor dehumidifier after being drawn in and filtered. When the clean humid air passes through the cold end of the semiconductor cooling chip, the moisture in it condenses into liquid water. The air after condensation and drying is then dried again by the silica gel drying and regeneration unit or heated and sent back to the buffer cabinet.
[0026] The heating temperature is controlled by comparing the temperature inside the buffer cabinet and the air temperature after passing through the heater.
[0027] When the humidity inside the buffer cabinet is ≤35%, the semiconductor dehumidifier and silica gel drying and regeneration unit will stop working.
[0028] When the humidity inside the buffer cabinet is between 35% and 40%, the entire device is in standby mode, monitoring the humidity inside the buffer in real time. When the humidity is greater than or equal to 40%, a new round of dehumidification and drying is started.
[0029] When the buffer cabinet needs to be opened to store or retrieve lithium ingots, the storage and retrieval mode is activated. At this time, the semiconductor dehumidifier stops working, but the air inside the buffer cabinet continues to circulate for storing or retrieving crude lithium.
[0030] The pressure inside the buffer cabinet should be 200-250 Pa higher than the ambient air pressure.
[0031] In one specific embodiment of the present invention, the silica gel drying and regeneration unit includes three modes:
[0032] When the temperature inside the buffer cabinet is detected to be lower than the ambient temperature and the value is not greater than 5°C, it enters the normal dehumidification mode; specifically, only one silica gel drying and regeneration device operates, which dries the air discharged from the semiconductor dehumidifier a second time and then sends it back to the buffer cabinet.
[0033] When the temperature inside the buffer cabinet is detected to be lower than the ambient temperature and greater than 5°C, the heating and circulating air mode is activated. Specifically, the two silica gel drying and regeneration devices are turned off, and only the heater is operated. The air discharged from the semiconductor dehumidifier is heated by the heater and then sent back to the buffer cabinet.
[0034] In normal dehumidification mode, if the difference between the temperature and humidity sensors before and after a silica gel drying and regeneration device is less than a threshold, the device enters regeneration dehumidification mode. Specifically, the silica gel drying and regeneration device to be regenerated is heated to reach and maintain the regeneration temperature, and the electric three-way valve is opened to connect it to the outside air.
[0035] Open the throttle valves before the two silica gel drying and regeneration devices, and control the amount of circulating air entering the cabinet of the normal silica gel drying and regeneration device to be regenerated to be more than the amount of circulating air entering the cabinet of the silica gel drying and regeneration device to be regenerated. Use part of the internally circulated dry air to regenerate the silica gel drying and regeneration device.
[0036] In one specific embodiment of the present invention, during the regeneration dehumidification mode, the electric three-way valve installed after the heater is opened in stages to allow external air to enter and balance the air used up in the cabinet.
[0037] In one specific embodiment of the present invention, if the pressure difference between the pressure inside the buffer cabinet and the ambient air pressure is less than 200 Pa, the electric three-way valve between the buffer cabinet and the semiconductor dehumidifier is opened to replenish air.
[0038] In one specific embodiment of the present invention, when the cache cabinet is to be opened to access lithium ingots, the ambient temperature is monitored at the same time, and the temperature inside the cache cabinet is no more than 5°C different from the ambient temperature.
[0039] Compared with existing technologies, the lithium metal dehumidification and buffering method and device of the present invention establishes an intelligent semiconductor-silicone column dual-stage circulating temperature and humidity control system to achieve automatic temperature and humidity control, timed data collection and ventilation, regenerable silica gel reduction, and semiconductor condensation dehumidification control functions in the lithium metal buffer transfer cabinet, meeting the requirements of precise system structure distribution and safe, reliable, and durable operation. Through testing, the present invention has achieved the technical effect of rapidly reducing the relative humidity in the buffer space from 80% to below 40% within 4 hours, and then reducing the relative humidity to below 30% ± 3% after 2 hours. Within three working days when the relative humidity is below 40%, no apparent oxidation occurs on the surface of the lithium metal, meeting the daily storage requirements for lithium metal. Attached Figure Description
[0040] Figure 1 A schematic diagram showing the structure of a lithium metal dehumidification and buffer device;
[0041] Figure 2 A schematic diagram showing the structure of a silica gel drying and regeneration device;
[0042] In the diagram, 1-Buffer cabinet, 2-Semiconductor dehumidifier, 3-Silica gel drying and regeneration unit, 4-Controller, 5-Air filter, 6-Exhaust fan, 7-First temperature and humidity sensor, 8-Second temperature and humidity sensor, 9-Third temperature and humidity sensor, 10-Pressure sensor, 11-First electric switching valve, 12-First silica gel drying and regeneration device, 13-Second silica gel drying and regeneration device, 14-Heater, 15-First throttle valve, 16-Second throttle valve, 17-Second electric switching valve, 18-First electric three-way valve, 19-Second electric three-way valve, 20-Third electric three-way valve; 21-Fourth electric three-way valve, 22-Fourth temperature and humidity sensor, 23-Fifth temperature and humidity sensor. Detailed Implementation
[0043] To further understand the present invention, embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the present invention.
[0044] An embodiment of the present invention discloses a lithium metal dehumidification and buffer device, such as... Figure 1 and Figure 2 As shown, it includes:
[0045] The buffer cabinet 1 is equipped with several first temperature and humidity sensors 7 and pressure sensors 10.
[0046] The air outlet of the buffer cabinet 1 is connected in sequence to the semiconductor dehumidifier 2 and the silica gel drying and regeneration unit 3 via pipes; in order to reduce the cabinet volume, the semiconductor dehumidifier 2 and the silica gel drying and regeneration unit 3 are respectively installed inside the buffer cabinet 1.
[0047] The air outlet of the silica gel drying and regeneration unit 3 is connected to the air inlet of the buffer cabinet 1;
[0048] A first electric switching valve 11 and an air filter 5 are installed between the buffer cabinet 1 and the semiconductor dehumidifier 2;
[0049] A fourth electric three-way valve 21 is also provided between the first electric switch valve 11 and the air filter 5;
[0050] An exhaust fan 6 is installed between the semiconductor dehumidifier 2 and the silica gel drying and regeneration unit 3;
[0051] At least two second temperature and humidity sensors 8 are provided in the semiconductor dehumidifier 2;
[0052] The cooling element inside the semiconductor dehumidifier 2 can dissipate the heat generated during the dehumidification process to the surrounding area of the cabinet through heat conduction via copper pipes and air cooling.
[0053] The semiconductor dehumidifier 2 is equipped with a water storage box.
[0054] After being filtered by air filter 5 to remove chlorine and dust from the electrolysis process plant, the air enters semiconductor dehumidifier 2. When the dew point is reached, the moisture in the air condenses into condensation, and the resulting liquid water is collected in a water storage box and then into a water collection bag. Primary dehumidification of the air is achieved within semiconductor dehumidifier 2.
[0055] The silica gel drying and regeneration unit 3 includes: a first silica gel drying and regeneration device 12, a second silica gel drying and regeneration device 13, and a heater 14 connected in parallel;
[0056] The first silica gel drying and regeneration device 12 and the second silica gel drying and regeneration device 13 are interchangeable and can be used after one regeneration, which improves the operating capacity; the first silica gel drying and regeneration device 12 and the second silica gel drying and regeneration device 13 are equipped with armored electric heating tape.
[0057] A first throttle valve 15 is installed in front of the first silica gel drying and regeneration device 12, and a first electric three-way valve 18 and a fourth temperature and humidity sensor 22 are installed at its rear end.
[0058] A second throttle valve 16 is installed before the second silica gel drying and regeneration device 13, and a second electric three-way valve 19 and a fifth temperature and humidity sensor 23 are installed at its rear end.
[0059] A second electric switching valve 17 is installed before the heater 14, and a third electric three-way valve 20 is installed at its rear end.
[0060] A third temperature and humidity sensor 9 is installed before the silica gel drying and regeneration unit 3.
[0061] The air undergoes two-stage dehumidification via the silica gel drying and regeneration unit 3.
[0062] The controller 4 receives signals from various temperature, humidity and pressure sensors in real time and controls the operation of the semiconductor dehumidifier 2 and the silica gel drying and regeneration unit 3 to achieve precise humidity regulation inside the cabinet.
[0063] It also includes a display screen that simultaneously displays temperature, humidity, and pressure data inside the buffer cabinet.
[0064] Embodiments of the present invention utilize the aforementioned lithium metal dehumidification and buffering device to implement a lithium metal dehumidification and buffering method, comprising the following steps:
[0065] Real-time monitoring of humidity, temperature, and pressure within cache cabinet 1;
[0066] When any humidity sensor inside the buffer cabinet 1 detects that the humidity inside the cabinet is ≥40%, the semiconductor dehumidifier 2 and the silica gel drying and regeneration unit 3 are activated. They collect the temperature inside the buffer cabinet 1 and the cold end temperature of the cooling unit of the semiconductor dehumidifier 2, and adjust the current of the semiconductor constant current driver to maintain the temperature difference between the cooling end and the circulating air between 14 and 18°C. This facilitates the condensation of water vapor in the circulating air through the cooling end, which then falls into the one-way check valve.
[0067] After being drawn in and filtered, the humid air enters the semiconductor dehumidifier 2. When the clean humid air passes through the cold end of the cooling chip of the semiconductor 2, the moisture in it condenses into liquid water. The air after condensation and drying is then dried again by the silica gel drying and regeneration unit 3 or heated and sent back to the buffer cabinet.
[0068] The silica gel drying and regeneration unit 3 includes three modes:
[0069] When the internal temperature of the buffer cabinet 1 is detected to be lower than the ambient temperature and the value is not greater than 5°C, it enters the normal dehumidification mode; specifically, only one silica gel drying and regeneration device operates, and the air discharged from the semiconductor dehumidifier 2 is dried a second time and then sent back to the buffer cabinet 1.
[0070] When the temperature inside the buffer cabinet is detected to be lower than the ambient temperature and greater than 5°C, the heating and circulating air mode is activated. Specifically, the two silica gel drying and regeneration devices are turned off, and only the heater 14 is operated. The air discharged from the semiconductor dehumidifier 2 is heated by the heater 14 and then sent back to the buffer cabinet 1. The heating temperature is controlled by comparing the temperature inside the buffer cabinet 1 and the air temperature after passing through the heater 14. The air temperature after passing through the heater 14 is 5°C higher than the temperature inside the buffer cabinet.
[0071] In normal dehumidification mode, the drying efficiency of the silica gel drying and regeneration device is determined by collecting the difference between the temperature and humidity sensors before and after the device, and whether heating regeneration is required. Specifically, if the difference between the third temperature and humidity sensor 9 and the fourth temperature and humidity sensor 22, or the difference between the third temperature and humidity sensor 9 and the fifth temperature and humidity sensor 23, is less than a threshold, the device enters regeneration dehumidification mode. Regeneration dehumidification involves heating the silica gel drying and regeneration device to be regenerated, bringing it to the regeneration temperature and maintaining it stably, and then opening the electric three-way valve to connect it to the outside air.
[0072] Open the throttle valves before the two silica gel drying and regeneration devices, and control the amount of circulating air entering the cabinet of the normal silica gel drying and regeneration device to be regenerated to be more than the amount of circulating air entering the cabinet of the silica gel drying and regeneration device to be regenerated. Use part of the internally circulated dry air to regenerate the silica gel drying and regeneration device.
[0073] During the regenerative dehumidification mode, the third electric three-way valve 20, which is set after the heater 14, is opened in stages to allow external air to enter and balance the air used up in the cabinet.
[0074] When the humidity inside the buffer cabinet 1 is ≤35%, the semiconductor dehumidifier 2 stops working; specifically, first stop the exhaust fan 6, and after the pressure inside the buffer cabinet 1 stabilizes, close all the switching valves and throttle valves to stop the semiconductor dehumidifier 2 and the silica gel drying unit 3 from working.
[0075] When the humidity inside the buffer cabinet is between 35% and 40%, the entire device is in standby mode, monitoring the humidity inside the buffer in real time. When the humidity is greater than or equal to 40%, a new round of dehumidification and drying is started. The hysteresis humidity threshold between 35% and 40% can reliably prevent the device from malfunctioning due to fluctuations in sensor sampling.
[0076] When the cache cabinet 1 is to be opened to store or retrieve lithium ingots, the ambient temperature is monitored at the same time. The temperature difference between the cache cabinet and the ambient temperature is no more than 5°C. The storage and retrieval mode is started. At this time, the semiconductor dehumidifier 2 stops working, but the air in the cache cabinet 1 continues to circulate for storing or retrieving crude lithium.
[0077] The pressure inside the buffer cabinet 1 should be 200-250 Pa higher than the ambient air pressure.
[0078] If the pressure difference between the buffer cabinet and the ambient air pressure is less than 200Pa, open the fourth electric three-way valve 21 between the buffer cabinet 1 and the semiconductor dehumidifier 2 to replenish air.
[0079] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.
[0080] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A lithium metal dehumidification and buffer device, characterized in that, include: The buffer cabinet is equipped with several temperature, humidity, and pressure sensors. The air outlet of the buffer cabinet is connected in sequence to a semiconductor dehumidifier and a silica gel drying and regeneration unit via pipes; The air outlet of the silica gel drying and regeneration unit is connected to the air inlet of the buffer cabinet; A first electrically operated valve and an air filter are installed between the buffer cabinet and the semiconductor dehumidifier; An exhaust fan is installed between the semiconductor dehumidifier and the silica gel drying and regeneration unit; Temperature and humidity sensors are installed in semiconductor dehumidifiers and silica gel drying and regeneration units. The controller receives signals from various temperature, humidity, and pressure sensors in real time and controls the operation of the semiconductor dehumidifier and silica gel drying and regeneration unit.
2. The lithium metal dehumidification and buffer device according to claim 1, characterized in that, The silica gel drying and regeneration unit includes two silica gel drying and regeneration devices and a heater connected in parallel. Each silica gel drying and regeneration unit is equipped with a throttle valve in front of it and an electric three-way valve and a temperature and humidity sensor at its rear end. A second electric switch valve is installed before the heater, and an electric three-way valve is installed at its rear end; A temperature and humidity sensor is installed before the silica gel drying and regeneration device.
3. The lithium metal dehumidification and buffer device according to claim 1, characterized in that, The semiconductor dehumidifier and the silica gel drying and regeneration unit are respectively installed inside the buffer cabinet.
4. The lithium metal dehumidification and buffer device according to claim 1, characterized in that, It also includes a display screen that simultaneously displays temperature, humidity, and pressure data inside the buffer cabinet.
5. The lithium metal dehumidification and buffer device according to claim 2, characterized in that, The silica gel drying and regeneration device is externally wrapped with an armored electric heating tape.
6. A method for dehumidifying and buffering lithium metal, characterized in that, Includes the following steps: Real-time monitoring of humidity, temperature, and pressure within the cache cabinet; When any humidity sensor in the buffer cabinet detects that the air humidity inside the cabinet is ≥40%, the semiconductor dehumidifier and silica gel drying and regeneration unit are activated. The humid air enters the semiconductor dehumidifier after being drawn in and filtered. When the clean humid air passes through the cold end of the semiconductor cooling chip, the moisture in it condenses into liquid water. The air after condensation and drying is then dried again by the silica gel drying and regeneration unit or heated and sent back to the buffer cabinet. The heating temperature is controlled by comparing the temperature inside the buffer cabinet and the air temperature after passing through the heater. When the humidity inside the buffer cabinet is ≤35%, the semiconductor dehumidifier and silica gel drying and regeneration unit will stop working. When the humidity inside the buffer cabinet is between 35% and 40%, the entire device is in standby mode, monitoring the humidity inside the buffer in real time. When the humidity is greater than or equal to 40%, a new round of dehumidification and drying is started. When the buffer cabinet needs to be opened to store or retrieve lithium ingots, the storage and retrieval mode is activated. At this time, the semiconductor dehumidifier stops working, but the air inside the buffer cabinet continues to circulate for storing or retrieving crude lithium. The pressure inside the buffer cabinet should be 200-250 Pa higher than the ambient air pressure.
7. The lithium metal dehumidification and buffering method according to claim 5, characterized in that, The silica gel drying and regeneration unit includes three modes: When the temperature inside the buffer cabinet is detected to be lower than the ambient temperature and the value is not greater than 5°C, it enters the normal dehumidification mode; specifically, only one silica gel drying and regeneration device operates, which dries the air discharged from the semiconductor dehumidifier a second time and then sends it back to the buffer cabinet. When the temperature inside the cache cabinet is detected to be lower than the ambient temperature and the value is greater than 5°C, the heated air circulation mode is activated. Specifically, the two silica gel drying and regeneration devices are shut down, and only the heater is operated. The air discharged from the semiconductor dehumidifier is heated by the heater and then sent back to the buffer cabinet. In normal dehumidification mode, if the difference between the temperature and humidity sensors before and after a silica gel drying and regeneration device is less than a threshold, the device enters regeneration dehumidification mode. Specifically, the silica gel drying and regeneration device to be regenerated is heated to reach and maintain the regeneration temperature, and the electric three-way valve is opened to connect it to the outside air. Open the throttle valves before the two silica gel drying and regeneration devices, and control the amount of circulating air entering the cabinet of the normal silica gel drying and regeneration device to be regenerated to be more than the amount of circulating air entering the cabinet of the silica gel drying and regeneration device to be regenerated. Use part of the internally circulated dry air to regenerate the silica gel drying and regeneration device.
8. The lithium metal dehumidification and buffering method according to claim 7, characterized in that, During the regenerative dehumidification mode, the electric three-way valve installed after the heater is opened in stages to allow outside air to enter and balance the air used up in the cabinet.
9. The lithium metal dehumidification and buffering method according to claim 6, characterized in that, If the pressure difference between the buffer cabinet and the ambient air pressure is less than 200Pa, open the electric three-way valve between the buffer cabinet and the semiconductor dehumidifier to replenish air.
10. The lithium metal dehumidification and buffering method according to claim 6, characterized in that, When opening the buffer cabinet to access lithium ingots, the ambient temperature is monitored simultaneously, and the temperature difference between the buffer cabinet and the ambient temperature is no more than 5°C.