High-temperature horizontal closed-loop circulating fluidized bed reaction system for producing silicon-carbon negative electrode material
Through the high-temperature horizontal closed-circuit circulating fluidized bed reaction system, the problems of low thermal energy utilization and large-scale production in the production of silicon carbon anode materials are solved, efficient and safe large-scale production and material uniformity are achieved, and the circulation stability and production capacity of the materials are improved.
Patent Information
- Application Number
- CN202510380262.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-28
- Publication Date
- 2025-07-11
AI Technical Summary
The traditional method of preparing silicon carbon negative electrode materials has problems such as large volume expansion, poor conductivity, low raw material utilization rate and high production costs, which leads to poor material circulation stability and difficulty in large-scale production. The vertical thermal radiation fluidized bed technology has the disadvantages of low thermal energy utilization, small output scale, and uneven temperature distribution.
The high-temperature horizontal closed-circuit fluidized bed reaction system is adopted, including metering hopper, gas distribution box, dual gate valve linkage discharge mechanism, electric heating pipe, filter and gas mixer, etc., through inert gas circulation and direct heating of activated carbon, uniform fluidization and efficient mixing are achieved, and combined with pulse back-cleaning and hydrogen adsorption device, silicon precipitation and carbon coating reaction are optimized.
It improves the efficiency of heat energy utilization, realizes large-scale industrial production, reduces gas consumption and exhaust emissions, enhances safety and production capacity, and ensures the uniformity and stability of materials.
Smart Images
Figure CN120285890A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a fluidized bed reaction system, in particular to a high-temperature horizontal closed-loop circulating fluidized bed reaction system for the production of silicon-carbon anode materials. Background Art
[0002] As a key technology for the next-generation lithium-ion batteries, silicon-carbon anode materials have significant advantages in improving the energy density and fast charging performance of batteries due to their theoretical specific capacity of up to 4200 mAh / g (more than 10 times that of graphite anodes). However, traditional preparation methods face challenges such as large volume expansion of silicon materials, poor electrical conductivity, low raw material utilization rate, and high production costs, resulting in poor cycle stability of the materials and difficulties in large-scale production. To solve these problems, fluidized bed reactor technology has gradually become the focus of the industry. Most of the currently disclosed technologies are vertical thermal radiation fluidized bed technologies, which have disadvantages such as low thermal energy utilization rate, small production scale, uneven temperature distribution, and difficulty in large-scale industrial production. Summary of the Invention
[0003] The technical problem to be solved by the present invention is to provide a high-temperature horizontal closed-loop circulating fluidized bed reaction system for the production of silicon-carbon anode materials, which has a simple structure, greatly improves the thermal energy utilization efficiency, and can be applied to large-scale industrial production.
[0004] To solve the above technical problems, the high-temperature horizontal closed-loop circulating fluidized bed reaction system for the production of silicon-carbon anode materials provided by the present invention includes a metering hopper, which is arranged at the feeding end of the fluidized bed reactor and is used for storing activated carbon and quantitatively conveying the activated carbon to the fluidized bed plate in the fluidized bed reactor through a screw conveyor; a gas distribution box, which is arranged at the lower end of the fluidized bed plate of the fluidized bed reactor; a double-gate valve linkage discharging mechanism, which is arranged at the discharging end of the fluidized bed reactor; electric heating tubes, which are arranged in the fluidized bed reactor and are used for directly heating the activated carbon and inert gas in the fluidized state; a filter, which is arranged in the fluidized bed reactor and above the electric heating tubes; the exhaust port at the top of the fluidized bed reactor is connected to the intake port of a circulating fan through a pipeline in sequence after passing through a gas cooler and a hydrogen adsorption device, the exhaust port of the circulating fan is connected to the first intake port of a gas mixer, and the exhaust port of the gas mixer is connected to the intake port of the gas distribution box through a pipeline in sequence after passing through an electric heater; a valve three for connecting a nitrogen gas source is connected to the intake port of the circulating fan, a valve four for connecting a silane gas source is connected to the second intake port of the gas mixer, and a valve five for connecting an acetylene gas source is connected to the third intake port of the gas mixer.
[0005] The above fluidized bed plate is a fluidized bed sieve plate with an aperture ratio of 1-4% to ensure uniform fluidization of the material.
[0006] The filter is also provided with a pulse backwashing pipe, and the gas outlet of valve three is connected to the gas source inlet end of the pulse backwashing pipe, which is used to blow back the filter with inert gas.
[0007] The metering hopper is connected to the fluidized bed reactor through a double-gate valve linkage feeding device.
[0008] Furthermore, a valve two is provided on one side of the hydrogen adsorption device for discharging the displacement gas.
[0009] The working method of the reaction system includes the following steps: A. Under the condition that valve one is closed, valve two and valve three are opened, start the circulation fan, open the linkage gate valve of the double-gate valve linkage feeding device, start the screw conveyor of the metering hopper, quantitatively add activated carbon particles onto the fluidized bed plate in the fluidized bed reactor, and then close the linkage gate valve of the double-gate valve linkage feeding device; B. Adjust the frequency of the circulation fan to make the activated carbon in the fluidized bed reactor in a fluidized state, and use inert gas to pulse backwash the filter. When the oxygen content in the fluidized bed reactor is less than 3 - 5%, open valve one, close valve two and valve three. At this time, the fluidized bed reactor is in an automatic air replenishment state, and the whole system is in a closed-loop circulation state; C. Turn on and adjust the electric heater and the electric heating tube so that the temperature of the gas entering the fluidized bed reactor and the temperature in the fluidized bed reactor are 100 - 300 °C and 300 - 600 °C respectively, and turn on the gas cooler to keep the circulating gas in the pipeline at 100 - 300 °C; D. Open and adjust valve four to keep the concentration of silane entering the fluidized bed reactor within 10% - 30%, maintain the silicon deposition reaction for 4 - 10 hours, then close valve four, adjust the fluidized bed reactor to 500 - 800 °C, open valve five to keep the concentration of acetylene entering the fluidized bed reactor within 10% - 30%, maintain the carbon coating for 4 - 10 hours, then close valve five and at the same time turn off the electric heater and the electric heating tube. When the temperature in the fluidized bed reactor is less than 45 °C, open the linkage gate valve of the double-gate valve linkage discharging mechanism for discharging to obtain the silicon-carbon anode material product.
[0010] E. After the hydrogen in the hydrogen adsorption device is desorbed, re-feed materials to carry out the next batch of production.
[0011] Technical effects of the present invention: a) The present invention adopts a horizontal fluidized bed reactor, in which the electric heating tubes are placed inside the fluidized bed reactor and directly contact with the activated carbon particles. It has a fast heating rate, uniform temperature distribution, and large production capacity (compared with vertical radiation heating), thus greatly improving the thermal energy utilization efficiency and can be applied to large-scale industrial production; b) The surface of the electric heating tubes of the present invention is treated with tungsten carbide spraying to prevent the activated carbon particles from causing wall breakage and deflagration accidents due to long-term friction with the electric heating tubes; c) The system of the present invention adopts an inert closed-loop cycle, and the unreacted silane and acetylene gases are recycled, reducing the consumption of silane, acetylene and inert gases, and at the same time improving the heat utilization efficiency; d) The by-product hydrogen gas of the silicon deposition and carbon coating reaction of the present invention is adsorbed and desorbed through a hydrogen adsorption device, reducing the exhaust gas emissions and potentially enabling further resource utilization; e) The present invention uses a Venturi mixer to mix silane, acetylene and inert gas, improving the gas mixing efficiency and preventing potential safety hazards caused by uneven mixing; f) The present invention adopts a double gate valve feeding and discharging device, and inert gas is used to protect the valves during operation to prevent the high-temperature gas in the reactor from leaking outwards. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention will be further described in detail below with reference to the accompanying drawings of the specification: Figure 1 It is a schematic structural diagram of a high-temperature horizontal closed-loop circulating fluidized bed reaction system for producing silicon-carbon anode materials of the present invention. DETAILED DESCRIPTION OF THE INVENTION EXAMPLE
[0013] As Figure 1 shown, the high-temperature horizontal closed-loop circulating fluidized bed reaction system for producing silicon-carbon anode materials in this example includes: A metering feed hopper 1 is arranged at the feeding end of the fluidized bed reactor 7 for storing activated carbon and quantitatively conveying the activated carbon to the fluidized bed plate 4 inside the fluidized bed reactor 7 through a screw conveyor; the fluidized bed plate is a fluidized bed sieve plate with an opening ratio of 1-4% to ensure uniform fluidization of the material. The metering feed hopper 1 is connected to the fluidized bed reactor 7 through a double gate valve linkage feeding device 2. The double gate valve linkage feeding device 2 is protected by inert gas during operation to ensure that the gas in the fluidized bed system does not leak outwards; A gas distribution box 3 is arranged at the lower end of the fluidized bed plate 4 of the fluidized bed reactor 7 to ensure uniform distribution of the hot air entering the fluidized bed reactor; A double gate valve linkage discharging mechanism 5 is arranged at the discharging end of the fluidized bed reactor 7; it is protected by inert gas during operation to ensure that the gas in the fluidized bed system does not leak outwards; The electric heating tube 6 is arranged inside the fluidized bed reactor and is used to directly heat the activated carbon and inert gas in the fluidized state. The working temperature range is 100 - 800 °C. To prevent damage caused by long-term friction with the material, tungsten carbide is sprayed on the surface of the electric heating tube. The filter 9 is arranged inside the fluidized bed reactor and above the electric heating tube 6. A pulse backwashing tube 10 is also provided on the filter 9. The gas outlet of the valve three 23 is connected to the gas source inlet end of the pulse backwashing tube 10, which is used to backflush the filter 9 with inert gas. Generally, inert gas at 0.6 - 0.8 Mpa is used for backflushing.
[0014] The exhaust port at the top of the fluidized bed reactor 7 is sequentially connected to the gas cooler 11 and the hydrogen adsorption device 12 through pipelines, and then connected to the inlet of the circulation fan 13 through the valve one 21. The outlet of the circulation fan 13 is connected to the first inlet of the gas mixer 14. The outlet of the gas mixer 14 is sequentially connected to the electric heater 15 and the inlet of the gas distribution box 3 through pipelines; a valve two 22 is provided on one side of the hydrogen adsorption device 12 for discharging the replacement gas.
[0015] The valve three 23 for connecting the nitrogen gas source is connected to the inlet of the circulation fan 13, the valve four 24 for connecting the silane gas source is connected to the second inlet of the gas mixer 14, and the valve five 25 for connecting the acetylene gas source is connected to the third inlet of the gas mixer 14.
[0016] The fluidized bed reactor 7 is provided with a rupture disc for relieving pressure when the system is overpressured. The rupture pressure is generally 20 - 40 kpa.
[0017] The filter 9 uses a metal or ceramic sintered filter, and the filtration accuracy is generally 0.5 - 2 μm.
[0018] The gas cooler 11 is generally a magnetic plate cooler, which cools the outlet temperature of the fluidized bed reactor 7 from 500 - 800 °C to 100 - 300 °C.
[0019] The hydrogen adsorption device 12 is a hydrogen adsorption device filled with metal hydride, which can adsorb the hydrogen generated by the cracking of silane and acetylene in the hydrogen adsorption device, and desorb the hydrogen in the hydrogen adsorption device to the tail gas treatment when the fluidized bed stops working.
[0020] The circulation fan 13 is a 0-leakage high-temperature and high-pressure explosion-proof fan, which is used for the circulation of inert gas in the high-temperature fluidized bed reactor.
[0021] The gas mixer 14 is a Venturi gas mixer, which is used for mixing silane and acetylene with inert gas.
[0022] The electric heater 15 is a magnetic plate electric heater, which is used for heating inert gas, and the heating temperature is 100 - 300 °C.
[0023] The working method of the above reaction system includes the following steps: A. Under the condition that valve 1-21 is closed and valves 2-22 and 3-23 are opened, start the circulating fan 13, open the linkage valve of the double-gate valve linkage feeding device 2, start the screw conveyor of the metering hopper 1, quantitatively add activated carbon particles onto the fluidized bed plate 4 in the fluidized bed reactor, and then close the linkage valve of the double-gate valve linkage feeding device 2; B. Adjust the frequency of the circulating fan 13 to make the activated carbon in the fluidized bed reactor 7 in a fluidized state, and perform pulse backwashing on the filter 9 with inert gas. When the oxygen content in the fluidized bed reactor is less than 3-5%, open valve 1 and close valves 2 and 3. At this time, the fluidized bed reactor is in an automatic air supplement state and the whole system is in a closed-loop circulation state; C. Start and adjust the electric heater 15 and the electric heating tube 6 to make the temperature of the gas entering the fluidized bed reactor and the temperature in the fluidized bed reactor be 100-300°C and 300-600°C respectively, and start the gas cooler 11 to keep the circulating gas in the pipeline at 100-300°C; D. Open and adjust valve 4-24 to keep the concentration of silane gas entering the fluidized bed reactor within 10%-30%, maintain the silicon deposition reaction for 4-10 hours, then close valve 4-24, adjust the temperature of the fluidized bed reactor to 500-800°C, open valve 5-25 to keep the concentration of acetylene gas entering the fluidized bed reactor within 10%-30%, maintain the carbon coating for 4-10 hours, then close valve 5-25 and at the same time close the electric heater 15 and the electric heating tube 6. When the temperature in the fluidized bed reactor is less than 45°C, open the linkage valve of the double-gate valve linkage discharging mechanism 5 to discharge the material, and obtain the silicon-carbon anode material product.
[0024] E. After the hydrogen in the hydrogen adsorption device 12 is completely desorbed, re-feed materials to carry out the next batch of production.
[0025] Working principle: Activated carbon particles with a size of 5-30 μm are in a fluidized state in a circulating inert gas (a typical gas is nitrogen) fluidized bed. When the temperature in the fluidized bed reactor is 300-600°C, silane gas is introduced to carry out the silicon deposition reaction: SiH4 → Si + 2H2, and the silicon produced by the silane cracking reaction is deposited in the pores of the activated carbon particles; when the temperature in the fluidized bed reactor is 500-800°C, acetylene gas is introduced to carry out the carbon coating reaction: C2H2 → 2C + H2, and the carbon produced by the acetylene cracking coats the surface of the activated carbon after silicon deposition, forming a silicon-carbon composite material with a special structure, which is particularly suitable for the anode material of the battery.
[0026] Obviously, the above embodiments are merely examples given to clearly illustrate the present invention and are not limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And these obvious changes or modifications derived from the spirit of the present invention are still within the protection scope of the present invention.
Claims
1. A high-temperature horizontal closed-circuit circulating fluidized bed reaction system for the production of silicon-carbon anode materials, characterized in that, Comprising: A metering hopper (1), provided at the feeding end of the fluidized bed reactor (7), for storing activated carbon and quantitatively conveying the activated carbon to the fluidized bed plate (4) in the fluidized bed reactor (7) through a screw conveyor; A gas distribution box (3), provided at the lower end of the fluidized bed plate (4) of the fluidized bed reactor (7); A double-gate valve linkage discharging mechanism (5), provided at the discharging end of the fluidized bed reactor (7); Electric heating tubes (6), provided in the fluidized bed reactor, for directly heating the activated carbon and inert gas in a fluidized state; A filter (9), provided in the fluidized bed reactor and above the electric heating tubes (6); The exhaust port at the top of the fluidized bed reactor (7) is connected in sequence through a pipeline to a gas cooler (11) and a hydrogen adsorption device (12), and then through a valve I (21) to the intake port of a circulation fan (13). The exhaust port of the circulation fan (13) is connected to the first intake port of a gas mixer (14). The exhaust port of the gas mixer (14) is connected in sequence through a pipeline to an electric heater (15) and to the intake port of the gas distribution box (3); A valve III (23) for connecting a nitrogen gas source is connected to the intake port of the circulation fan (13). A valve IV (24) for connecting a silane gas source is connected to the second intake port of the gas mixer (14). A valve V (25) for connecting an acetylene gas source is connected to the third intake port of the gas mixer (14).
2. The reaction system according to claim 1, characterized in that, The above-mentioned fluidized bed plate is a fluidized bed sieve plate with an aperture ratio of 1 - 4% to ensure uniform fluidization of the material.
3. The reaction system according to claim 1, wherein A pulse backwashing pipe (10) is further provided on the filter (9). The outlet of the valve III (23) is connected to the gas source inlet end of the pulse backwashing pipe (10) for back-blowing the filter (9) with an inert gas.
4. The reaction system according to claim 3, wherein, The metering hopper (1) is connected to the fluidized bed reactor (7) through a double-gate valve linkage feeding device (2).
5. The reaction system according to any one of claims 1-4, characterized in that, A valve II (22) is provided on one side of the hydrogen adsorption device (12) for discharging the replacement gas.
6. The reaction system according to any one of claims 1-4, characterized in that, The surface of the electric heating tubes is treated by tungsten carbide spraying.
7. A working method of a reaction system as claimed in claim 4, characterized in that, Including the following steps: A. Under the condition that the valve I (21) is closed, the valve II (22) and the valve III (23) are opened, start the circulation fan (13), open the linkage gate valve of the double-gate valve linkage feeding device (2), start the screw conveyor of the metering hopper (1), quantitatively add activated carbon particles onto the fluidized bed plate (4) in the fluidized bed reactor, and then close the linkage gate valve of the double-gate valve linkage feeding device (2); B. Adjust the frequency of the circulation fan (13) to make the activated carbon in the fluidized bed reactor (7) in a fluidized state, and perform pulse back-blowing on the filter (9) with an inert gas. When the oxygen content in the fluidized bed reactor is less than 3 - 5%, open the valve I, close the valve II and the valve III. At this time, the fluidized bed reactor is in an automatic air supplement state, and the whole system is in a closed-loop circulation state; C. Turn on and adjust the electric heater (15) and the electric heating tube (6) so that the temperature of the gas entering the fluidized bed reactor and the temperature inside the fluidized bed reactor are 100 - 300 °C and 300 - 600 °C respectively, and turn on the gas cooler (11) to keep the circulating gas in the pipeline at 100 - 300 °C; D. Open and adjust valve four (24) to keep the silane concentration entering the fluidized bed reactor within 10% - 30%, maintain the silicon deposition reaction for 4 - 10 hours, then close valve four (24), adjust the fluidized bed reactor to 500 - 800 °C, open valve five (25), keep the acetylene concentration entering the fluidized bed reactor within 10% - 30%, maintain the carbon coating for 4 - 10 hours, then close valve five (25) and at the same time turn off the electric heater (15) and the electric heating tube (6). When the temperature inside the fluidized bed reactor is less than 45 °C, open the interlocking gate valve of the double gate valve interlocking discharging mechanism (5) for discharging to obtain the silicon-carbon anode material product.
8. The working method of the reaction system according to claim 7, characterized in that, After the hydrogen in the hydrogen adsorption device (12) is completely desorbed, re-feed materials for the next batch of production.