Lithium battery negative electrode material pre-carbonization system

Abstract

The invention discloses a lithium battery cathode material pre-carbonization system which comprises a rotary heater, a cooling kiln and a combustion furnace, an air inlet cover and an air outlet cover are arranged outside the rotary heater, a plurality of material channels are arranged in the rotary heater, and a high-temperature heating channel communicated with the air inlet cover and the air outlet cover is arranged on the periphery of each material channel. The smoke exhaust end of the combustion furnace is communicated with the air inlet cover; a gas channel structure is arranged between the gas inlet cover and the rotary heater; and after the gas medium in the gas outlet pipeline is cooled, one path of the gas medium enters the combustion furnace, and the other path of the gas medium enters the gas channel structure. According to the invention, the temperature rise in the material channel is stable and uniform, the thickness of the material layer is reduced, and the temperature uniformity of the material with poor heat transfer rate is better. And direct contact between the air inlet cover and the rotary heater is avoided, the thermal deformation probability of the air inlet of the kiln body is reduced, and meanwhile, the possibility that an internal heat-preservation refractory material falls off is also reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium battery negative electrode production, and in particular relates to a lithium battery negative electrode material precarbonization system. Background Art

[0002] Pre-carbonization is an important production process in the production of lithium battery negative electrode materials (artificial graphite). Its purpose is to improve the efficiency of graphitization in subsequent processes, save production costs and improve the environment. At present, the industry uses tunnel kilns and external heating rotary heaters to solve this production process. In the actual production process, both methods have certain drawbacks.

[0003] 1. The advantages of tunnel kiln are that the working temperature can be higher (lined with refractory materials), the residence time can be longer, so the quality of the product is relatively stable and the failure rate is low. Its disadvantages are high production cost, waste heat cannot be fully utilized, products need to be shipped in saggers, which are both consumables and energy loss carriers, production requires loading and unloading, continuous production is not proper, large amount of flue gas is emitted, the flue gas composition is complex, and environmental protection requirements are high. At the same time, it occupies a large area and other disadvantages.

[0004] 2. The traditional external heating rotary heater uses the external heating method of the metal cylinder to continuously produce materials, avoids the sagger loading, and uses the combustion of its own volatile components to heat the cylinder. The production cost is low, environmental protection is improved, and the footprint is small. However, due to the high temperature performance of metal materials, in this structure, the working temperature is limited, the material runs unevenly, and the heating is uneven, resulting in poor product quality, which seriously affects the graphitization production. At the same time, during pre-carbonization, when the volatile tar gas is separated from the material, the temperature drop can easily cause the tar gas to liquefy and cause pipe blockage. The failure rate is high during the production process, and the production continuity is often not strong. Summary of the invention

[0005] In view of the above technical problems, the purpose of the present invention is to provide a lithium battery negative electrode material precarbonization system that can evenly and stably heat the material and utilize the waste heat.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The lithium battery negative electrode material precarbonization system includes a feeding mechanism, a rotary heater, a cooling kiln, and a combustion furnace. The discharge end of the feeding mechanism is connected to the feed end of the rotary heater to feed the negative electrode material into the rotary heater; the material discharge end of the rotary heater is connected to the inlet end of the cooling kiln to allow the carbonized material in the rotary heater to enter the cooling kiln; the smoke discharge end of the combustion furnace is connected to the high-temperature heating channel in the rotary heater.

[0008] An air inlet hood and an air outlet hood are arranged outside the rotary heater, and a plurality of material channels are arranged inside the rotary heater. A high-temperature heating channel connected to the air inlet hood and the air outlet hood is arranged on the periphery of each material channel, and the smoke exhaust end of the combustion furnace is connected to the air inlet hood; a gas channel structure is arranged between the air inlet hood and the rotary heater;

[0009] The gas outlet hood is connected with a gas outlet pipe for discharging the gas medium in the high-temperature heating channel from the gas outlet hood. After being cooled, the gas medium in the gas outlet pipe enters the combustion furnace and the gas channel structure.

[0010] As a further embodiment, a distribution cavity is provided at the feed end of the rotary heater, and a distributor is provided at the end of each material channel in the distribution cavity, and the distributor guides the material in the distribution cavity to the corresponding material channel; the distributor adopts a material receiving trough obliquely arranged at the end of the material channel.

[0011] As a further embodiment, the rotary heater is formed by assembling segmented heater bodies, an intermediate connecting section is provided between the segmented heater bodies, the intermediate connecting section includes an intermediate connecting shell fixedly connected to the segmented heater bodies, a connecting channel connected to the material channel and a gas connecting pipe connected to the high-temperature heating channel between the segmented heater bodies is provided in the intermediate connecting shell;

[0012] A corrugated expansion structure is arranged in the connecting channel; the gas connecting pipeline comprises a first connecting pipe, a second connecting pipe and a corrugated tube, the first connecting pipe and the second connecting pipe respectively connect the heating channels in the segmented heater body, and the corrugated tube is connected between the first connecting pipe and the second connecting pipe.

[0013] As a further embodiment, the gas passage structure includes a first isolation member that separates the gas inlet hood from the outer peripheral wall of the rotary heater;

[0014] An axial channel and a radial channel connected to the axial channel are provided in the first isolation component. The axial channel is arranged axially along the outer peripheral wall of the rotary heater. The axial channel is located between the air inlet hood and the outer peripheral wall of the rotary heater, and the radial channel is located outside the air inlet hood. An air vent connected to the radial channel is provided on the first isolation component, and the air vent is connected to the above-mentioned air outlet pipe. The axial channel is connected to the inside of the air inlet hood.

[0015] As a further embodiment, the gas channel structure further includes a second isolation component covered on the outer peripheral wall of the rotary heater, the second isolation component is located on the inner side of the first isolation component, a rotary seal is formed between the inner side of the first isolation component and the second isolation component, and an annular spacing channel is formed between the inner wall of the second isolation component and the outer peripheral wall of the rotary heater;

[0016] An air intake duct assembly connected to the spacing channel is arranged in the rotary heater. The air intake duct assembly is rotatably connected to a rotating support component at the end of the rotary heater. A first rotating joint connected to the air intake duct assembly is mounted on the rotating support component; the first rotating joint is connected to the above-mentioned air outlet duct.

[0017] As a further embodiment, the cooling kiln has a hot material inlet and a cold material outlet, and the hot material inlet is connected to the material discharge end of the rotary heater; a cooling material channel connected to the hot material inlet and the cold material outlet is formed in the cooling kiln, and a first heat recovery pipe group and a second heat recovery pipe group are arranged on the inner circumference of the cooling kiln along the length direction of the cooling kiln, the first heat recovery pipe group is close to the hot material inlet side, and the second heat recovery pipe group is close to the cold material outlet side, heat exchange gas is passed into the first heat recovery pipe group, and hot water is passed into the second heat recovery pipe group.

[0018] As a further embodiment, the first heat recovery pipe group includes at least a first heat recovery gas pipeline arranged on the inner periphery of the cooling kiln, the first heat recovery gas pipeline extends from the hot material inlet toward the inner periphery of the middle part of the cooling kiln and is arranged on the inner periphery of the cooling kiln to form a first heat recovery gas pipe layer, and both ends of the first heat recovery gas pipeline extend to the outside of the cooling kiln, one end is used as a gas inlet end, and the other end is used as a gas outlet end.

[0019] As a further embodiment, the second heat recovery pipe group includes a water distribution chamber, a water collection chamber, a second rotary joint, and a heat recovery water pipe group. The second rotary joint is installed at one end of the cooling kiln close to the cold material outlet. The second rotary joint includes an inlet channel and an outlet channel. The water distribution chamber is connected to the water inlet pipe, and the water collection chamber is connected to the water outlet channel. The heat recovery water pipe group is connected between the water collection chamber and the water distribution chamber, and the heat recovery water pipe group extends from the cold material outlet toward the inner circumference of the middle part of the cooling kiln.

[0020] As a further embodiment, a separation and processing device is provided at the volatile matter discharge end of the rotary heater, and the separation and processing device includes an indirect heat exchange device, a cooling device, and a gas-solid separation device;

[0021] The volatile matter discharge end is connected to the indirect heat exchange device, the indirect heat exchange device is connected to the cooling device, the cooling device is connected to the inlet end of the gas-solid separation device, the gas discharge end of the gas-solid separation device is connected to the fuel gas inlet end of the combustion furnace, and the solid discharge end of the gas-solid separation device is connected to the material discharge end of the rotary heater;

[0022] The high-temperature flue gas generated by the combustion furnace provides a heat source for the indirect heat exchange device, so that the volatile matter passing through the indirect heat exchange device is cracked at 1100-1200°C; the cooling device cools the gas-solid mixture after the volatile tar is heated by the indirect heat exchange device and cracked to a low-temperature gas-solid separation temperature of 120-160°C and enters the gas-solid separation device.

[0023] By adopting the above technical solution, compared with the prior art, the present invention produces at least the following beneficial effects:

[0024] 1. By adopting multiple material channels and setting a heating channel outside each material channel, the material temperature in each material channel can be made more uniform; compared with the traditional kiln with the same diameter, the heat exchange area is correspondingly increased, and the diameter of the material channel is slightly reduced, the material temperature in the material channel is more uniform, and the material layer thickness is also reduced. The temperature uniformity of materials with poor heat transfer rate is better, especially for materials that require low temperature deviation during the heating process, which highlights its superiority. Due to the relatively improved heat transfer rate, the production capacity disadvantage can be compensated by increasing the kiln body speed and increasing the installation inclination of the equipment.

[0025] 2. By adopting the gas channel structure, direct contact between the air inlet hood and the rotary heater can be avoided, and the heat diffusion capacity of the air inlet hood itself toward the kiln body can be reduced, thereby reducing the temperature at the air inlet of the rotary heater accordingly, which can reduce the requirements for the material of the rotary heater and the probability of thermal deformation at the air inlet of the kiln body accordingly, and also reduce the possibility of internal thermal insulation refractory material falling off.

[0026] 3. The heat of the gas exhausted from the high-temperature heating channel of the rotary heater is utilized, one part enters the combustion furnace for air distribution, and the other part enters the gas channel structure as an isolation protective gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the system of the present invention;

[0028] Figure 2 The internal structure of the rotary heater in the present invention is shown in FIG. Figure 1 ;

[0029] Figure 3 The internal structure of the rotary heater in the present invention is shown in FIG. Figure 2 ;

[0030] Figure 4 It is a structural schematic diagram of the rotary heater and the air inlet hood in the present invention;

[0031] Figure 5 It is a schematic diagram of the external structure of the cooling kiln in the present invention;

[0032] Figure 6 It is a schematic diagram of the internal structure of the cooling kiln in the present invention;

[0033] Figure 7 It is a schematic diagram of the cross-sectional structure of the first heat recovery tube group in the present invention;

[0034] Figure 8It is a schematic diagram of the cross-sectional structure of the second heat recovery tube group in the present invention;

[0035] Fig. 9 for Figure 6 The enlarged schematic diagram of the middle A part;

[0036] Fig.10 for Figure 6 The enlarged schematic diagram of the middle part B;

[0037] Fig.11 It is a schematic diagram of a separation and treatment device for volatile components of a rotary heater in the present invention;

[0038] The reference numerals in the accompanying drawings represent the following:

[0039] 10. Feeding mechanism, 11. Rotary heater, 12. Cooling kiln, 13. Combustion furnace, 14. Feeding bin, 15. Buffer bin, 16. Metering rotary valve, 17. High temperature heating channel, 18. Air inlet hood, 19. Air outlet hood;

[0040] 20. Material channel, 21. Material distribution cavity, 22. Material distributor, 23. Intermediate connecting section, 24. Intermediate connecting shell, 25. Communication channel, 26. Corrugated expansion structure, 27. First communication pipe, 28. Second communication pipe, 29. Corrugated pipe;

[0041] 30. air outlet pipe, 31. first isolation component, 32. axial channel, 33. radial channel, 34. vent, 35. high-temperature air inlet channel, 36. connecting hole, 37. second isolation component, 38. sealing ring, 39. rotating seal;

[0042] 40. interval channel, 41. air inlet duct assembly, 42. rotating support component, 43. first rotating joint, 44. waste heat utilization device, 45. gas purification device, 46. pressurized fan, 47. hot material inlet, 48. cold material outlet, 49. cooling material channel;

[0043] 50. first heat recovery gas pipeline, 51. second heat recovery gas pipeline, 52. water distribution chamber, 53. water collection chamber, 54. second rotary joint, 55. heat recovery water pipe group, 56. water inlet channel, 57. water outlet channel, 58. outer sealing plate, 59. inner sealing plate;

[0044] 60. rear cylinder, 61. pipe body, 62. heat recovery water pipeline, 63. baffle, 64. connecting rod, 65. air intake expansion joint, 66. volatile matter discharge end, 67. indirect heat exchange device, 68. cooling device, 69. gas-solid separation device;

[0045] 70. induced draft fan, 71. first pipeline, 72. second pipeline, 73. exhaust gas discharge pipeline, 74. heat exchanger. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] See also Figure 1 As shown, the lithium battery negative electrode material precarbonization system includes a feeding mechanism 10, a rotary heater 11, a cooling kiln 12, and a combustion furnace 13. The discharge end of the feeding mechanism 10 is connected to the feed end of the rotary heater 11, and is used to feed the negative electrode material into the rotary heater 11 for precarbonization treatment in the rotary heater 11; the feeding mechanism 10 includes a feeding bin 14, a buffer bin 15, and a metering rotary valve 16. The feeding bin 14 is used to receive incoming materials. The top of the buffer bin 15 is connected to the bottom of the feeding bin 14, and the bottom of the buffer bin 15 is connected to the metering rotary valve 16. After passing through the metering rotary valve 16, the material enters the rotary heater 11. The metering rotary valve 16 is used to transfer the negative electrode material to the rotary heater 11. The rotary valve can measure the material entering the rotary heater 11 to obtain an accurate feed amount; the material discharge end of the rotary heater 11 is connected to the entrance end of the cooling kiln 12, so that the carbonized material in the rotary heater 11 can enter the cooling kiln 12. The negative electrode material after high temperature in the rotary heater 11 has a high temperature, so it needs to enter the cooling kiln 12 for cooling; the flue gas discharge end of the combustion furnace 13 is connected to the high-temperature heating channel in the rotary heater 11, that is, the combustion products of the combustion furnace 13 are passed into the high-temperature heating channel 17, providing a heat source for increasing the temperature of the negative electrode material in the rotary heater 11.

[0048] See also Figure 2 , 3As shown, the cross section of the rotary heater 11 is a circular body, the cross section of the material channel is a circular body, and the cross section of the high temperature heating channel 17 is a circular ring. The rotary heater 11 can be rotated under external drive, and an air inlet hood 18 and an air outlet hood 19 are arranged outside the rotary heater 11. The rotary heater 11 can adopt the structure of an existing rotary kiln to form a rotary rotation, and the air outlet hood 19 and the air inlet hood 18 are arranged using the hood structure of the rotary kiln, which will not be described in detail here; a plurality of material channels 20 are arranged in the heater, and a plurality of material channels 20 are arranged on the periphery of each material channel 20. A high-temperature heating channel 17 connected to an air inlet hood 18 and an air outlet hood 19 is respectively provided. The smoke exhaust end of the combustion furnace 13 is connected to the air inlet hood 18, and the high-temperature smoke exhausted from the combustion furnace 13 is sent into the high-temperature heating channel 17 through the air inlet hood 18; a plurality of material channels 20 are arranged along the axial direction of the rotary heater 11, and the plurality of material channels 20 are respectively connected between the feed end and the discharge end of the rotary heater 11, that is, the material at the feed end can enter the plurality of material channels 20 respectively, and be discharged from the discharge end respectively, through A plurality of material channels 20 are adopted and a high-temperature heating channel 17 is arranged outside each material channel 20, so that the material forms a plurality of channels and is transmitted from the feed end to the discharge end in the rotary heater 11, and heat transfer is formed in each material channel 20 through the high-temperature heating channel 17, so that the material in the material channel 20 is heated. The structural arrangement of the plurality of material channels 20 avoids the problem of low uniformity of material heating in a single material channel 20, and relatively speaking, the heat exchange area of ​​the material in the high-temperature heating channel 17 and the material channel 20 is increased, and the heat transfer capacity is correspondingly improved, so that the temperature of the material in each material channel 20 is more uniform; compared with the traditional kiln of the same diameter, the heat exchange area is correspondingly increased, and the diameter of the material channel 20 is slightly reduced, the material temperature in the material channel 20 is more uniform, and the material layer thickness is also reduced, and the temperature uniformity of the material with poor heat transfer rate is better, especially for the material requiring low temperature deviation during the heating process, which highlights its superiority. Since the heat transfer rate is relatively improved, the production capacity disadvantage can be compensated by increasing the rotation speed of the rotary heater 11 and increasing the installation inclination of the equipment.

[0049] Through the structural design of multiple material channels 20 and multiple high-temperature heating channels 17, the entire periphery of the rotary heater 11 is not entirely a heated surface (compared with the high-temperature flue gas channels surrounding the periphery of the traditional rotary heater 11, the annular cross-sections of the high-temperature flue gas channels are all stress points), and the force structure between the material channel 20 and the heating channel is changed (that is, a portion of a single heating channel is close to the periphery of the rotary heater 11, and a portion is inside the rotary heater 11, and the high-temperature heating channel 17 is only the portion close to the periphery of the rotary heater 11 as a stress point), thereby reducing the waste caused by heat diffusing outward through the periphery of the rotary heater 11 and greatly improving the working temperature of the rotary heater 11. At the same time, due to the change of the force structure, non-metallic materials can be used as the forming components of the material channel 20. The forming components can be made of silicon carbide, graphite, carbon-carbon plates, ceramic tubes, etc. By using non-metallic materials, the working temperature can be higher. Generally, all-metal materials are used. Even if high-temperature alloys are used, the maximum temperature is ≤1000°C. Under the condition of the same material, the working temperature can be increased by 100-150°C. Since most of the heat exchange surfaces between the channels are not subject to external forces and the support points of the rotary heater 11 can be more distributed, the material thickness is also greatly reduced, thereby reducing the cost of the rotary heater 11 and increasing the service life of the rotary heater 11.

[0050] Among them, the air inlet hood 18 and the air outlet hood 19 are relatively fixedly arranged outside the rotary heater 11, that is, when the rotary heater 11 rotates, the air inlet hood 18 and the air outlet hood 19 do not rotate with it. The air inlet hood 18 and the air outlet hood 19 are sealed with the rotary heater 11 by a rotary sealing structure, which is a common technology and will not be described in detail here. In addition, an auxiliary electric heater can be added in the high-temperature heating channel 17. The auxiliary electric heater can be used together with the above-mentioned high-temperature flue gas to increase the temperature in the high-temperature heating channel 17, or it can be used alone to heat the high-temperature heating channel 17. The auxiliary electric heater can be an electric heating wire or an electrically heated silicon carbon rod. An electric receiving slip ring is added to the rotary heater 11 to transmit the electric energy of the auxiliary electric heater, so as to provide more heating methods for the rotary heater 11. The electric receiving slip ring involved here is mainly to provide stable power transmission for the auxiliary electric heater when the rotary heater 11 rotates. It is a prior art and will not be described in detail here.

[0051] Among them, the high-temperature heating channel 17 is arranged in a ring shape around the outside of the material channel 20 along the length direction of the material channel 20, that is, the high-temperature heating channel 17 is evenly distributed around the outside of the material channel 20. The high temperature in the high-temperature heating channel 17 can transfer heat more evenly to the material channel 20, so that the material in the material channel 20 is heated evenly.

[0052] A material distribution cavity 21 is provided at the feeding end of the rotary heater 11, and a material discharging cavity is provided at the discharging end. The material distribution cavity 21 is used to receive the material transmitted by the feeding mechanism 10, and the material discharging cavity is used to receive the heated material and discharge it from the rotary heater 11 in a centralized manner and send it into the cooling kiln 12. A distributor 22 is provided at the end of each material channel 20 in the material distribution cavity 21, and the distributor 22 guides the material in the material distribution cavity 21 to the corresponding material channel 20. The distributor 22 can be a receiving trough obliquely arranged at the end of the material channel 20. When the rotary heater 11 rotates, the material in the material distribution cavity 21 can be guided to the material channel 20 through the distributor 22.

[0053] The rotary heater 11 is formed by assembling two segmented heater bodies, and of course the number of segments can also be set according to the length of the rotary heater 11; an intermediate connecting section 23 is arranged between the segmented heater bodies, and the intermediate connecting end is fixedly connected to the two segmented heater bodies by flanges. The intermediate connecting section 23 includes an intermediate connecting shell 24 fixedly connected to the segmented heater bodies, and a connecting channel 25 connected to the material channel 20 is arranged in the intermediate connecting shell 24, which is used to connect the material channels 20 on both sides of the intermediate connecting end, and the gas connecting pipe connecting the high-temperature heating channel 17 between the segmented heater bodies, and is used for the high-temperature flue gas in the high-temperature heating channel 17 on both sides of the intermediate connecting section 23. Through the setting of the intermediate connecting section 23, the kiln body length requirements and the material heating residence time requirements can be met as much as possible, and at the same time, it can also avoid the problem of difficult transportation when the rotary heater 11 is long, and solve the corresponding problems caused by the use of a longer kiln body.

[0054] In order to eliminate the problem of thermal expansion of the rotary heater 11, a corrugated expansion structure 26 is provided in the connecting channel 25, that is, the inner wall of the connecting channel 25 is provided with a corrugated expansion surface to compensate for the thermal expansion. In addition, the gas connecting pipeline includes a first connecting pipe 27, a second connecting pipe 28, and a bellows pipe 29. The first connecting pipe 27 and the second connecting pipe 28 are respectively connected to the heating channels in the segmented heater body, and the bellows pipe 29 is connected between the first connecting pipe 27 and the second connecting pipe 28. The number and inner diameter of the gas connecting pipes are set as needed, which are mainly used to form a connecting flow at high temperature in the heating channel, and the setting of the bellows pipe 29 can compensate for the problem of thermal expansion.

[0055] A gas channel structure is provided between the air inlet hood 18 and the rotary heater 11; the air outlet hood 19 is connected to an air outlet pipe 30 for discharging the gas medium in the high-temperature heating channel 17 from the air outlet hood 19. After being cooled, the gas medium in the air outlet pipe 30 enters the combustion furnace 13 and the gas channel structure, so that the waste heat discharged from the rotary heater 11 can be reused.

[0056] See also Figure 4 As shown, the gas channel structure includes a first insulating component 31 that separates the air intake hood 18 from the outer peripheral wall of the rotary heater 11, and the first insulating component 31 forms a rotary seal with the outer peripheral wall of the rotary heater 11. The first insulating component 31 is provided with an axial channel 32 and a radial channel 33 connected to the axial channel 32. The axial channel 32 is axially arranged along the outer peripheral wall of the rotary heater 11. The axial channel 32 is located between the air intake hood 18 and the outer peripheral wall of the rotary heater 11. The heat transfer capacity between the air intake hood 18 and the rotary heater 11 can be hindered by the axial channel 32; the radial channel 33 is located outside the air intake hood 18. Through the provision of the radial channel 33, the heat on the side of the air intake hood 18 can be isolated, and the heat diffusion of the air intake hood 18 to the side is reduced.

[0057] Vents 34 connected to the radial channels 33 are respectively provided on both sides of the first isolation component 31. The vents 34 are connected to the above-mentioned outlet pipe 30. The cooled gas in the outlet channel is sent into the radial channels 33 and the axial channels 32 through the vents 34 to further enhance the heat insulation capacity and cool the air intake hood 18, thereby extending the service life of the air intake hood 18.

[0058] The axial channel 32 is connected with the air inlet hood 18, that is, the axial channel 32 is connected with the high-temperature air inlet channel 35 in the air inlet hood 18. A connecting hole 36 whose size is smaller than the cross section of the axial channel 32 is provided at the connection point between the axial channel 32 and the high-temperature air inlet channel 35. Here, by connecting the axial channel 32 with the high-temperature air inlet channel 35, the low-temperature gas in the axial channel 32 can be mixed with the high-temperature flue gas and enter the high-temperature heating channel 17 in the rotary heater 11, so that the temperature of the high-temperature flue gas entering the rotary heater 11 can be adjusted as needed; and by arranging the connecting hole 36, the flow capacity of the gas in the axial channel 32 toward the high-temperature air inlet channel 35 can be increased, and it can be better mixed with the high-temperature flue gas. Of course, the formation of the connecting hole 36 here is not limited to the use of opening a through hole on the plate, and a baffle can also be provided at the end of the axial channel 32, and there is a gap between the baffle and the inner wall of the axial channel 32 to form the connecting hole 36.

[0059] In order to further reduce the outer peripheral temperature of the kiln body between the rotary heater 11 and the air inlet hood 18, the gas channel structure also includes a second isolation component 37 which is covered on the outer peripheral wall of the rotary heater 11. The second isolation component 37 can be fixedly arranged on the outer peripheral wall of the rotary heater 11. The second isolation component 37 is located on the inner side of the first isolation component 31. A rotary seal is formed between the inner side of the first isolation component 31 and the second isolation component 37. That is, a sealing ring 38 can be fixed on the inner side of the first isolation component 31. The two ends of the sealing ring 38 extend toward the two ends of the first isolation component 31 to increase the distance between the end of the sealing ring 38 and the air inlet hood 18. A rotary seal 39 is provided between the end of the sealing ring 38 and the outer wall of the second isolation component 37 for sealing. An annular spacing channel 40 is formed between the inner wall of the second isolation component 37 and the outer peripheral wall of the rotary heater 11. The spacing channel 40 is arranged axially along the outer peripheral wall of the rotary heater 11, that is, the distance between the spacing channel 40 on both sides of the air inlet hood 18 is extended to increase the heat insulation distance.

[0060] In order to allow low-temperature gas to pass into the interval channel 40, an air intake duct assembly 41 connected to the interval channel 40 is arranged in the rotary heater 11. The air intake duct assembly 41 is rotatably connected to a rotating support component 42 at the end of the rotary heater 11. The rotating support component 42 is a component for supporting the rotation of the rotary heater 11 and is a commonly used component of the rotary heater 11. A first rotary joint 43 connected to the air inlet pipe assembly 41 is mounted on the rotating support component 42, and the first rotary joint 43 is connected to the above-mentioned air outlet pipe 30; wherein, the air inlet pipe assembly 41 includes a radial tube radially arranged in the rotary heater 11 and an axial tube connected to the radial tube, the axial tube is rotatably arranged on the rotating support component, and the radial tube is connected to the spacing channel 40; the first rotary joint 43 is located on the outside of the rotating support component, and the first rotary joint 43 is connected to the air outlet pipe 30, that is, the low-temperature gas in the air outlet pipe 30 can enter the spacing channel 40, and the spacing channel 40 can also be connected to a discharge port for the gas in the spacing channel 40 to be discharged, so as to allow the subsequent continuous inflow of low-temperature gas to enhance the thermal insulation protection capability.

[0061] Among them, a guide structure for changing the flow of the fluid therein can be set in the spacing channel 40, the axial channel 32, and the radial channel 33. The guide structure here can adopt a spiral channel, a guide plate, a guide hole plate, etc., mainly to extend the flow path of the gas in the channel to enhance the thermal insulation capacity.

[0062] In order to process the gas discharged from the gas outlet hood 19 through the gas outlet channel, a waste heat utilization device 44, a gas purification device 45, and a pressurized fan 46 can also be set. The waste heat utilization device 44 (heat exchanger) is connected to the gas outlet channel, that is, the exhaust gas discharged from the rotary heater 11 has a relatively high temperature, and this temperature can be utilized by the waste heat utilization device 44 to reduce the exhaust gas temperature, such as preheating the air entering the combustion furnace 13 to increase the temperature of the air entering the combustion furnace 13; the waste heat utilization device 44 is connected to the gas purification device 45, and the gas purification device 45 can be used to filter particulate matter in the exhaust gas and purify the gas; the gas exhaust end of the gas purification device 45 is connected to the pressurized fan 46, and the pressurized fan 46 is connected to the vent 34. Through the setting of the pressurized fan 46, the gas entering the first thermal insulation component can generate a certain pressure, so that it can enter the high-temperature air inlet channel 35 more stably and mix with the high-temperature flue gas.

[0063] Two air ducts can be separated at the outlet of the pressurizing fan 46, one air duct is connected to the vent 34, and the other is connected to the first rotary joint 43, and the low-temperature gas is delivered to the spacing channel 40, the axial channel 32, and the radial channel 33 through a pressurizing fan 46. By arranging the gas channel structure between the air inlet hood 18 and the rotary heater 11, the main material of the rotary heater 11 can be the original main material, the thickness can be appropriately reduced, and the maximum working temperature of the main material of the rotary heater 11 is ≤300°C; the second isolation component 37 is relatively unaffected by external forces, so that the material for making the second isolation component 37 can be reduced in thickness, and the maximum working temperature is ≤500°C; the working temperature of the connecting hole 36 at the end of the axial channel 32 is about 2 / 3 of the temperature of the entering high-temperature flue gas; the above-mentioned structural design reduces the heat diffusion capacity of the air inlet hood 18 itself toward the kiln body, thereby correspondingly reducing the temperature at the air inlet of the rotary heater 11, which can reduce the requirements for the material of the rotary heater 11, and can also reduce the probability of thermal deformation at the air inlet of the rotary heater 11 accordingly, and also reduce the possibility of falling off of the internal thermal insulation refractory material, while reducing the production cost of the rotary heater 11 and improving the safety.

[0064] See also Figure 5-10As shown, the high-temperature material discharged from the rotary heater 11 is directly discharged into the cooling kiln 12, and the material is stored in the cooling kiln 12 to avoid material storage at the rear of the heating kiln and reduce the number of failure points. The cooling kiln 12 can form a rotary operation, and has a hot material inlet 47 and a cold material outlet 48. The hot material inlet 47 is connected to the material discharge end of the rotary heater 11; a cooling material channel 49 is formed in the cooling kiln 12 to form a connection with the hot material inlet 47 and the cold material outlet 48. The high-temperature material discharged from the end of the rotary heater 11 enters the cooling kiln 12 from the hot material inlet 47, and is discharged from the cold material outlet 48 after being cooled.

[0065] The first heat recovery pipe group and the second heat recovery pipe group are arranged along the inner circumference of the cooling kiln 12 along the length direction of the cooling kiln 12, respectively cooling the high-temperature materials and obtaining the heat in the high-temperature materials while cooling. The first heat recovery pipe group is close to the hot material inlet 47, and the second heat recovery pipe group is close to the cold material outlet 48. The incoming high-temperature materials are first cooled down, and the heat is recovered from the high-temperature materials after the heat is recovered by the first hot water return pipe group, so as to further reduce the temperature of the high-temperature materials. Heat exchange gas is passed into the first heat recovery pipe group, and heat exchange water is passed into the second heat recovery pipe group. After the heat exchange gas in the first heat recovery pipe group cools down the high-temperature materials, the temperature is increased, and it can be used in heating equipment, drying equipment, as a high-temperature air distribution in the combustion furnace 13, and other occasions where high-temperature gas is needed. Among them, the hot water in the second heat recovery pipe group enters at low temperature, cools the high-temperature material, and is discharged as high-temperature water. It can be stored in a centralized manner for use by hot water supply equipment or hot water users. By first using the heat exchange gas to enter the first heat recovery pipe group, the heat exchange gas passing through the first heat recovery pipe group can obtain a better temperature rise, thereby increasing the use scenarios of the high-temperature heat exchange gas.

[0066] The first heat recovery pipe group at least includes a first heat recovery gas pipeline 50 arranged on the inner periphery of the cooling kiln 12, the first heat recovery gas pipeline 50 extends from the hot material inlet 47 toward the inner periphery of the middle part of the cooling kiln 12 and is arranged on the inner periphery of the cooling kiln 12 to form a first heat recovery gas pipeline layer, and both ends of the first heat recovery gas pipeline 50 extend to the outside of the cooling kiln 12, one end is used as a gas inlet end, and the other end is used as a gas outlet end. The first heat recovery gas pipeline 50 can be arranged in the cooling kiln 12 in a circuitous, spiral, or other manner to increase the heat exchange area of ​​the first heat recovery gas pipeline 50 in the cooling kiln 12, accelerate the cooling effect of the high-temperature material, and increase the gas temperature rise in the first heat recovery gas pipeline 50.

[0067] In order to further obtain the cooling capacity for high-temperature materials and increase the circulation volume of heat exchange gas, the first heat recovery pipe group includes at least a second heat recovery gas pipe 51 arranged on the inner side of the first heat recovery gas pipe layer. The second heat recovery gas pipe 51 is arranged in the same manner as the first heat recovery gas pipe 50. The second heat recovery gas pipe 51 forms a second heat recovery gas pipe layer on the inner side of the first heat recovery gas pipe layer, that is, from the radial direction of the cooling kiln 12, the first heat recovery gas pipe 50 is on the outer side of the second heat recovery gas pipe 51. Of course, a third heat recovery gas pipe or more may be added accordingly as needed. The position of the heat recovery gas pipe in the cooling kiln 12 is not limited to the inner peripheral position, but may also be arranged at the central position in the diameter direction of the cooling kiln 12. The specific number and arrangement positions of the heat recovery gas pipes are set according to needs.

[0068] The second heat recovery pipe group includes a water distribution chamber 52, a water collection chamber 53, a second rotary joint 54, and a heat recovery water pipe group 55. The second rotary joint 54 is installed at one end of the cooling kiln 12 close to the cold material outlet 48. The second rotary joint 54 includes an inlet channel 56 and an outlet channel 57. The inlet channel 56 is located on the outside of the outlet channel 57. The water distribution chamber 52 is connected to the water inlet pipe, and the water collection chamber 53 is connected to the water outlet channel 57. The heat recovery water pipe group 55 is connected between the water collection chamber 53 and the water distribution chamber 52. The heat recovery water pipe group 55 extends from the cold material outlet 48 toward the inner circumference of the middle part of the cooling kiln 12. Here, low-temperature cold water is mainly used to enter the water distribution chamber 52 through the water inlet channel 56, and the low-temperature cold water is sent to the heat recovery water pipe group 55 through the water distribution chamber 52, so as to cool the high-temperature material and increase the temperature of the low-temperature cold water to form high-temperature hot water. After the high-temperature hot water is collected by the water collection chamber 53, it is discharged through the water outlet channel 57, so as to cool the high-temperature material, and recover and reuse the heat through the temperature increase of the low-temperature cold water. Among them, the heat recovery water pipe group 55 here can also be arranged in the cooling kiln 12 in a spiral or circuitous manner to increase its heat exchange area in the cooling kiln 12, so as to accelerate the cooling effect of the high-temperature material and increase the temperature increase of the cold water in the heat recovery water pipe group 55.

[0069] The water-dividing chamber 52 and the water-collecting chamber 53 are arranged inside or outside the cooling kiln 12 near the cold material outlet 48; that is, the water-dividing chamber 52 and the water-collecting chamber 53 are arranged inside the end of the cooling kiln 12, and an outer sealing plate 58 and an inner sealing plate 59 are fixedly arranged at the end of the cooling kiln 12, and a water-collecting chamber 53 connected with the water outlet channel 57 is formed between the outer sealing plate 58 and the inner sealing plate 59, and a rear cylinder 60 is fixed to the inner side of the inner sealing plate 59 of the cooling kiln 12, and a water-dividing chamber 52 is formed inside the rear cylinder 60, and the rear cylinder 60 is connected with the pipe body 61 forming the water outlet channel 57, so that the water-dividing chamber 52 and the water-collecting chamber 53 are formed inside the cooling kiln 12. Of course, a part of the components from the rightmost end to the left of the rear cylinder 60 can also be arranged outside the cooling kiln 12, so that the water-dividing chamber 52 and the water-collecting chamber 53 are formed outside the cooling kiln 12.

[0070] The heat recovery water pipe group 55 includes a plurality of heat recovery water pipes 62 connected between the water collecting chamber 53 and the water distributing chamber 52. The plurality of heat recovery water pipes 62 are distributed on the inner periphery of the cooling kiln 12. From the radial direction of the cooling kiln 12, at least one heat recovery water pipe layer is formed along the radial direction of the cooling kiln 12. What is expressed here is that a plurality of heat recovery water pipes 62 are connected in parallel between the water collecting chamber 53 and the water distributing chamber 52. The plurality of heat recovery water pipes 62 are used to guide the water in the water distributing chamber 52 to the water collecting chamber 53, and in the process of flow, the high-temperature material is cooled and the temperature of the water itself is increased; in order to obtain better heat recovery and cooling effects, multiple layers of heat recovery water pipe layers can be arranged in the radial direction of the cooling.

[0071] A baffle assembly is provided in the cooling kiln 12, and is arranged along the axial length of the first heat recovery pipe group or / and the second heat recovery pipe group in the cooling kiln 12. The baffle assembly includes a plurality of baffles 63 fixedly provided in the cooling kiln 12 and arranged at intervals, and a connecting rod 64 for connecting the baffles 63 to enhance the stability of the baffles; the baffles 63 are used to extend the flow path of the high-temperature material in the cooling material channel 49 to enhance the cooling effect on the high-temperature material.

[0072] The gas inlet end of the first heat recovery gas pipeline 50 is equipped with an air inlet expansion joint 65 to compensate for pipeline deformation caused by thermal expansion and contraction, etc., and reduce the risk of leakage at the pipeline connection.

[0073] The above-mentioned traditional rotary heater 11 is divided into two sections, front and back, to form a double cooling structure, that is, the high-temperature part is cooled by air, and the low-temperature part is cooled by water. At the same time, the shell-and-tube heat exchange structure is combined with the rotary heater 11 to increase the heat exchange area, reduce the length and diameter of the kiln body, save the investment cost and floor space of the cooling kiln 12, and the hot air exchanged in the high-temperature area can be used as waste heat for drying materials, heating, and combustion, so as to achieve energy conversion and save energy. The cooling kiln 12 adopts a dual-element cooling method to fully utilize preheating. The front section preheats the air, and the heated air is reused for water cooling in the rear section. The material leaves the cooling kiln below 1250°C, which is convenient for collection.

[0074] See also Fig.11 As shown, the volatile matter discharge end 66 of the rotary heater 11 is provided with a separation and processing device for allowing the tar-containing gas and the corresponding impurity dust to flow in and guide them to the separation device for processing; the separation and processing device includes an indirect heat exchange device 67, a cooling device 68, and a gas-solid separation device 69; wherein, the indirect heat exchange device 67 performs heat radiation heat exchange between the high-temperature side and the low-temperature side without contact. The non-contact heat exchange is adopted here mainly to avoid the tar-containing gas from mixing with other media and affecting the subsequent separation effect; the cooling device 68 cools the low-temperature medium passing therethrough without contact, and reduces the temperature of the high-temperature medium passing therethrough, thereby achieving the cooling effect; the gas-solid separation device 69 can separate the introduced gas-solid mixture into gas and solid, and it is a bag dust collector to obtain the effects of good gas permeability and high dust removal efficiency.

[0075] The volatile matter discharge end 66 is connected to the secondary side inlet end of the indirect heat exchange device 67, the secondary side outlet end of the indirect heat exchange device 67 is connected to the secondary side inlet end of the cooling device 68, the secondary side outlet end of the cooling device 68 is connected to the inlet end of the gas-solid separation device 69, the tar-containing gas enters the secondary side of the indirect heat exchange device 67 through the volatile matter discharge end 66, and a high-temperature fluid medium is introduced into the primary side of the indirect heat exchange device 67 to increase the temperature of the tar-containing gas on the secondary side and treat the tar-containing gas. The cooling device 68 can cool the high-temperature gas-solid mixture discharged from the secondary side of the indirect heat exchange device 67 to reduce the temperature of the high-temperature gas-solid mixture entering the gas-solid separation device 69, thereby reducing damage to the gas-solid separation device 69. The cooling device 68 also uses an indirect heat exchanger that passes low-temperature water / low-temperature refrigerant; an induced draft fan 70 is installed at the discharge end of the gas-solid separation device 69 to assist the fluidity of the tar-containing gas in the corresponding pipeline system; specifically, the high-temperature flue gas generated by the combustion furnace 13 provides a heat source for the indirect heat exchange device 67, so that the temperature of the volatile matter in the secondary side of the indirect heat exchange device 67 rises to 1100-1200°C. Under this temperature environment, the long-chain molecules in the tar gas can be cracked into small molecular gases (CO, H2, CH4). After cooling by the cooling device 68, the gas-solid separation device 69 is used to separate the micropowder contained in the gas, that is, the small molecular gas can be obtained and discharged through the drainage of the induced draft fan 70. The micropowder discharge end at the bottom of the gas-solid separation device 69 is connected to the material discharge end of the rotary heater 11, that is, the micropowder material is discharged from the end of the rotary heater 11 into the cooling kiln 12 for recycling. The cooling device 68 cools the gas-solid mixture after the volatile tar cracking heated by the indirect heat exchange device 67 to a low-temperature gas-solid separation temperature of 120-160° C. and enters the gas-solid separation device 69 for gas-solid separation.

[0076] The exhaust end of the induced draft fan 70 is connected to a first pipe 71 and a second pipe 72, and control valves are installed on the first pipe 71 and the second pipe 72 respectively, which are used to control the gas flow of each pipe; wherein, the small molecule gas discharged from the first pipe 71 can be stored as a combustible gas; and the second pipe 72 is connected to the combustion furnace 13, that is, it is sent into the combustion furnace 13 for combustion, so that the combustion furnace 13 can produce high-temperature gas, and the gas exhaust end of the combustion furnace 13 is connected to the primary side inlet end of the indirect heat exchange device 67, and the high-temperature gas generated in the combustion furnace 13 can be sent to the primary side of the indirect heat exchange device 67, and non-contact heat exchange is performed with the tar-containing gas in the secondary side, so that the tar-containing gas is heated and cracked. The primary side outlet end of the indirect heat exchange device 67 is connected to an exhaust gas exhaust pipe 73 for the low-temperature gas passing through the primary side to be discharged. Of course, the indirect heat exchange device 67 can also be directly arranged at the tail of the combustion furnace 13 to perform direct combustion heat exchange in the combustion furnace 13.

[0077] The indirect heat exchange device 67 can adopt a silicon carbide shell and tube heat exchanger, so that the high-temperature gas generated in the combustion furnace 13 can efficiently heat exchange and heat up the tar-containing gas, making the tar-containing gas cracking process more stable.

[0078] Among them, the induced draft fan 70 is driven by a variable frequency motor, mainly to enable the induced draft fan 70 to have a variable speed induced draft capability, such as being adjustable according to the air flow rate entering the volatile matter discharge end 66. When the air flow rate is small, the rotation speed of the induced draft fan 70 can be increased to accelerate the drainage force of the induced draft fan 70. When the air flow rate is large, the rotation speed of the induced draft fan 70 can be reduced to reduce the drainage force of the induced draft fan 70, so that the time that the tar-containing gas stays in the indirect heat exchange device 67 is slightly prolonged, that is, the cracking time of the tar-containing gas in the indirect heat exchange device 67 is also prolonged, thereby ensuring the stability of the cracking of the tar-containing gas.

[0079] A heat exchanger 74 is arranged between the exhaust gas discharge pipe 73 and the air inlet pipe of the combustion furnace 13. The heat exchanger 74 here can be integrated with the above-mentioned waste heat utilization device 44, or can be arranged on the air inlet pipe of the combustion furnace 13 from low to high according to the temperature of the heating gas entering each. The high-temperature exhaust gas in the exhaust gas discharge pipe 73 forms a heat exchange with the low-temperature air in the air inlet pipe. In order to obtain a sufficient combustion environment in the combustion furnace 13, a certain amount of air is introduced into the combustion furnace 13. The exhaust gas discharged from the exhaust gas discharge pipe 73 can preheat the air entering the combustion furnace 13 to reduce the heat energy damage in the combustion furnace 13.

[0080] The indirect heat exchange device 67 may be provided with a temperature sensor for detecting the temperature of the volatile components in the secondary side of the indirect heat exchange device 67. The temperature sensor may monitor the cracking temperature of the tar-containing gas, and the cracking condition of the tar-containing gas may be obtained accordingly. Of course, the temperature sensor may also be operated in conjunction with the control valves on the first and second pipelines, that is, when the temperature sensor detects that the temperature value is higher than or within the set range, the opening degree of the control valve on the second pipeline 72 may be reduced to appropriately reduce the amount of combustible gas entering the combustion furnace 13, and the opening degree of the control valve on the first pipeline 71 may be increased to increase the flow rate of the combustible gas in the first pipeline 71; and when the temperature value detected by the temperature sensor is lower than the set range, the opening degree of the control valve on the second pipeline 72 may be increased to increase the flow rate of the combustible gas in the second pipeline 72, and improve the combustion capacity in the combustion furnace 13, so as to make reasonable use of the combustible gas and avoid waste of resources.

[0081] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A lithium battery negative electrode material precarbonization system, comprising a feeding mechanism, a rotary heater, a cooling kiln, and a combustion furnace, wherein the discharge end of the feeding mechanism is connected to the feed end of the rotary heater to feed the negative electrode material into the rotary heater; the material discharge end of the rotary heater is connected to the inlet end of the cooling kiln to allow the carbonized material in the rotary heater to enter the cooling kiln; the smoke discharge end of the combustion furnace is connected to the high-temperature heating channel in the rotary heater, characterized in that: An air inlet hood and an air outlet hood are arranged outside the rotary heater, and a plurality of material channels are arranged inside the rotary heater. A high-temperature heating channel connected to the air inlet hood and the air outlet hood is arranged on the periphery of each material channel, and the smoke exhaust end of the combustion furnace is connected to the air inlet hood; a gas channel structure is arranged between the air inlet hood and the rotary heater; The gas outlet hood is connected with a gas outlet pipe for discharging the gas medium in the high-temperature heating channel from the gas outlet hood. After being cooled, the gas medium in the gas outlet pipe enters the combustion furnace and the gas channel structure.

2. The lithium battery negative electrode material precarbonization system according to claim 1, characterized in that: The feed end of the rotary heater is provided with a distribution cavity, and each material channel end in the distribution cavity is provided with a distributor, which guides the material in the distribution cavity to the corresponding material channel; the distributor adopts a material receiving trough obliquely arranged at the end of the material channel.

3. The lithium battery negative electrode material precarbonization system according to claim 1, characterized in that: The rotary heater is formed by assembling segmented heater bodies, and an intermediate connecting section is arranged between the segmented heater bodies. The intermediate connecting section includes an intermediate connecting shell fixedly connected to the segmented heater bodies, and a connecting channel connected to the material channel and a gas connecting pipe connected to the high-temperature heating channel between the segmented heater bodies are arranged in the intermediate connecting shell. A corrugated expansion structure is arranged in the connecting channel; the gas connecting pipeline comprises a first connecting pipe, a second connecting pipe and a corrugated tube, the first connecting pipe and the second connecting pipe respectively connect the heating channels in the segmented heater body, and the corrugated tube is connected between the first connecting pipe and the second connecting pipe.

4. The lithium battery negative electrode material precarbonization system according to claim 1, characterized in that: The gas passage structure includes a first insulating member that separates the gas inlet hood from the outer peripheral wall of the rotary heater; An axial channel and a radial channel connected to the axial channel are provided in the first isolation component. The axial channel is arranged axially along the outer peripheral wall of the rotary heater. The axial channel is located between the air inlet hood and the outer peripheral wall of the rotary heater, and the radial channel is located outside the air inlet hood. An air vent connected to the radial channel is provided on the first isolation component, and the air vent is connected to the above-mentioned air outlet pipe. The axial channel is connected to the inside of the air inlet hood.

5. The lithium battery negative electrode material precarbonization system according to claim 4, characterized in that: The gas channel structure also includes a second isolation component covered on the outer peripheral wall of the rotary heater, the second isolation component is located on the inner side of the first isolation component, a rotary seal is formed between the inner side of the first isolation component and the second isolation component, and an annular spacing channel is formed between the inner wall of the second isolation component and the outer peripheral wall of the rotary heater; An air intake duct assembly connected to the spacing channel is arranged in the rotary heater. The air intake duct assembly is rotatably connected to a rotating support component at the end of the rotary heater. A first rotating joint connected to the air intake duct assembly is mounted on the rotating support component; the first rotating joint is connected to the above-mentioned air outlet duct.

6. The lithium battery negative electrode material precarbonization system according to claim 1, characterized in that: The cooling kiln has a hot material inlet and a cold material outlet, and the hot material inlet is connected with the material discharge end of the rotary heater; a cooling material channel connected with the hot material inlet and the cold material outlet is formed in the cooling kiln, and a first heat recovery pipe group and a second heat recovery pipe group are arranged on the inner circumference of the cooling kiln along the length direction of the cooling kiln, the first heat recovery pipe group is close to the hot material inlet side, and the second heat recovery pipe group is close to the cold material outlet side, heat exchange gas is passed into the first heat recovery pipe group, and hot water is passed into the second heat recovery pipe group.

7. The lithium battery negative electrode material precarbonization system according to claim 6, characterized in that: The first heat recovery pipe group includes at least a first heat recovery gas pipeline arranged on the inner periphery of the cooling kiln, the first heat recovery gas pipeline extends from the hot material inlet toward the inner periphery of the middle part of the cooling kiln and is arranged on the inner periphery of the cooling kiln to form a first heat recovery gas pipe layer, both ends of the first heat recovery gas pipeline extend to the outside of the cooling kiln, one end is used as a gas inlet end, and the other end is used as a gas outlet end.

8. The lithium battery negative electrode material precarbonization system according to claim 6 or 7, characterized in that: The second heat recovery pipe group includes a water distribution chamber, a water collection chamber, a second rotary joint, and a heat recovery water pipe group. The second rotary joint is installed at one end of the cooling kiln close to the cold material outlet. The second rotary joint includes an inlet channel and an outlet channel. The water distribution chamber is connected to the water inlet pipe, and the water collection chamber is connected to the water outlet channel. The heat recovery water pipe group is connected between the water collection chamber and the water distribution chamber. The heat recovery water pipe group extends from the cold material outlet toward the inner circumference of the middle part of the cooling kiln.

9. The lithium battery negative electrode material precarbonization system according to claim 1, characterized in that: A separation and processing device is provided at the volatile matter discharge end of the rotary heater, and the separation and processing device includes an indirect heat exchange device, a cooling device, and a gas-solid separation device; The volatile matter discharge end is connected to the indirect heat exchange device, the indirect heat exchange device is connected to the cooling device, the cooling device is connected to the inlet end of the gas-solid separation device, the gas discharge end of the gas-solid separation device is connected to the fuel gas inlet end of the combustion furnace, and the solid discharge end of the gas-solid separation device is connected to the material discharge end of the rotary heater; The high-temperature flue gas generated by the combustion furnace provides a heat source for the indirect heat exchange device, so that the volatile matter passing through the indirect heat exchange device is cracked at 1100-1200°C; the cooling device cools the gas-solid mixture after the volatile tar is heated by the indirect heat exchange device and cracked to a low-temperature gas-solid separation temperature of 120-160°C and enters the gas-solid separation device.

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