Multistage circulating axial partition activated carbon purification process, system and rotary kiln

Abstract

This invention discloses a multi-stage circulating axial partition activated carbon purification process, system, and rotary kiln, belonging to the field of functional carbon material preparation technology. The rotary kiln of this invention has guide screws in its feed cylinder, discharge cylinder, inner cylinder, and outer cylinder. The guide screws in the feed cylinder and inner cylinder are right-handed, while those in the discharge cylinder and outer cylinder are left-handed. A first guide plate is provided between the outer cylinder and the inner cylinder, near the feed cylinder end. A second guide plate is provided inside the outer cylinder, near the discharge cylinder end. A first window is machined on the inner cylinder wall near the feed cylinder end, and a second window is machined on the inner cylinder wall wall near the discharge cylinder end. This invention, through optimized design of the rotary kiln structure, ensures complete pyrolysis purification of activated carbon without increasing the length of the reaction zone or the equipment footprint, thereby improving the overall cost-effectiveness of the process.

Description

Technical Field

[0001] This invention belongs to the field of functional carbon material preparation technology, and more specifically, relates to a multi-stage circulating axial partition activated carbon purification process, system and rotary kiln. Background Technology

[0002] Activated carbon, due to its extremely high specific surface area, well-developed pore structure, good chemical stability and conductivity, is widely used in the field of energy storage and conversion. It is one of the key materials for manufacturing supercapacitor electrodes and lithium-ion / sodium-ion battery anode materials. Its performance directly determines the energy density, power density and cycle life of energy storage devices.

[0003] High-performance activated carbon for batteries is typically produced from carbon-containing precursors such as coconut shells, coal, petroleum coke, and biomass through high-temperature pyrolysis and activation processes. Among these processes, high-temperature pyrolysis (carbonization) is the fundamental stage for forming the initial carbon structure and pores, while activation (physical or chemical activation) is the key step for expanding the specific surface area and forming a rich pore size distribution.

[0004] While chemical activation methods (typically using KOH, NaOH, ZnCl2, H3PO4, etc. as activating agents) can yield activated carbon with high specific surface area at relatively low temperatures, they generally suffer from the following unavoidable drawbacks:

[0005] 1. Strong corrosiveness and equipment wear: Strong alkali or strong acid activators are highly corrosive to reaction equipment (such as kilns), which greatly increases the manufacturing and maintenance costs of the equipment.

[0006] 2. Environmental pollution risk: The chemically activated product must undergo repeated acid washing and water washing to remove activator residues and introduced impurity ions (such as K+). + Na + This process generates a large amount of acidic and alkaline wastewater, which is difficult to treat and poses a high risk of environmental pollution, contradicting the concept of green manufacturing.

[0007] 3. Product purity issues: Although the complex washing process can remove most of the chemical reagents, trace metal impurities are hard to avoid. These impurity ions may catalyze side reactions during long-term battery cycling, damaging the battery's coulombic efficiency and cycle stability.

[0008] Physical activation methods avoid the use of chemical reagents, making them more environmentally friendly, but they typically require higher activation temperatures and longer reaction times. For battery applications, especially high-end applications, the purity of activated carbon materials is a crucial performance indicator. High ash content (especially in poorly conductive silicates and aluminates) reduces the overall conductivity of activated carbon materials, decreases effective active lithium / sodium storage sites, and leads to side reactions with the electrolyte, resulting in capacity decay and shortened cycle life.

[0009] Currently available physical activation devices typically extend the reaction time by lengthening the reaction zone. However, the rigidity of these devices and their extremely low cost-effectiveness make them unsuitable for the current market. Therefore, there is an urgent need to develop a new, green, and efficient integrated purification and activation technology that can simultaneously and efficiently remove impurities during high-temperature pyrolysis activation without occupying excessive floor space. This eliminates the need for subsequent complex chemical cleaning steps and directly yields high-purity activated carbon products suitable for high-performance batteries.

[0010] A search revealed that Chinese patent application No. 2017200114317 discloses a double-layer rotary kiln. The kiln's shell is a sleeve structure, consisting of an outer shell and an inner shell. The inner shell is cylindrical, while the outer shell is barrel-shaped. One end of the inner shell connects to the feed inlet, while the other end does not contact the bottom of the outer shell. Counter-clockwise rotating helical blades are arranged between the inner and outer shells, and clockwise rotating helical blades are arranged inside the inner shell. This rotary kiln structure can extend the heating time of materials within the kiln, thus shortening its length and reducing its footprint. However, its effect is relatively limited and cannot effectively guarantee the complete reaction of the materials. Summary of the Invention

[0011] To address the problem that existing technologies typically require extending the reaction zone to prolong the activated carbon purification reaction time, resulting in lower equipment rigidity and cost-effectiveness, this invention provides a multi-stage circulating axial partitioned rotary kiln for activated carbon purification. By optimizing the structure of the rotary kiln, this invention allows the material to circulate in multiple stages along the axial direction of the kiln as needed. This ensures that the material can fully react within the rotary kiln without increasing the length of the reaction zone or the equipment footprint, thus guaranteeing the pyrolysis purification effect of the activated carbon.

[0012] The present invention also provides an activated carbon purification system comprising the above-described rotary kiln;

[0013] The present invention also provides an activated carbon purification process. By optimizing the structure of the rotary kiln, the activated carbon can be fully pyrolyzed and purified without increasing the length of the reaction zone or the equipment footprint, thereby improving the overall cost-effectiveness of the process.

[0014] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0015] The first aspect of this invention provides a rotary kiln for multi-stage circulating axial partition activated carbon purification, the rotary kiln comprising:

[0016] A rotary cylinder assembly, comprising an inner cylinder and an outer cylinder coaxially mounted;

[0017] The feed cylinder is located at one end of the rotary drum assembly and is used to feed the material to be purified into the rotary drum assembly.

[0018] And a discharge cylinder, which is located at the other end of the rotary cylinder assembly, for conveying the purified material out of the rotary kiln;

[0019] The feed cylinder, discharge cylinder, inner cylinder and outer cylinder are all equipped with guide screws, and the guide screws of the feed cylinder and inner cylinder are right-handed, while the guide screws of the discharge cylinder and outer cylinder are left-handed.

[0020] A first guide plate is provided between the outer cylinder and the inner cylinder and near the feed cylinder. A first window is correspondingly machined on the inner cylinder wall near the feed cylinder. When the rotary kiln rotates counterclockwise, the material in the outer cylinder can be guided into the inner cylinder through the first window via the first guide plate. When the rotary kiln rotates clockwise, the material in the inner cylinder can be guided into the outer cylinder via the first guide plate.

[0021] A second guide plate is provided inside the outer cylinder and near the discharge cylinder. When the rotary kiln rotates clockwise, the material in the outer cylinder can be discharged into the discharge cylinder through the second guide plate. A second window is correspondingly machined on the cylinder wall of the inner cylinder near the discharge cylinder. When the rotary kiln rotates counterclockwise, the material in the inner cylinder can enter the outer cylinder through the second window.

[0022] According to any rotary kiln of the first aspect of the present invention, the two ends of the first guide plate are respectively fixedly connected to the outer wall of the inner cylinder and the inner wall of the outer cylinder, and a plurality of first guide plates are provided at intervals along the circumference of the inner cylinder.

[0023] The inner cylinder has multiple first windows machined on its wall, and multiple first guide plates and multiple first windows are arranged alternately along the circumference of the inner cylinder.

[0024] According to any rotary kiln of the first aspect of the present invention, a plurality of second guide plates are provided inside the outer cylinder and at one end near the discharge cylinder, which are spaced apart in the circumferential direction.

[0025] The inner cylinder has a plurality of second windows that are spaced apart along its circumference on the end wall of the cylinder near the discharge cylinder, and the second windows are located on the inner side of the second guide plate.

[0026] According to any rotary kiln of the first aspect of the present invention, the feed cylinder, the discharge cylinder and the rotary cylinder assembly are all provided with heat preservation devices on their outer sides. A rolling ring is provided on the outer side of the heat preservation device of the feed cylinder, and the rolling ring is supported by a roller device. A toothed ring is provided on the outer side of the heat preservation device of the discharge cylinder, and the toothed ring is connected to a motor drive so as to drive the entire equipment to rotate.

[0027] The discharge port of the discharge cylinder is equipped with a kiln tail cover, and a second sealing device is provided between the kiln tail cover and the outer wall of the discharge cylinder.

[0028] A second aspect of the present invention provides a multi-stage circulating axial partition activated carbon purification system, which includes any of the rotary kilns described in the first aspect of the present invention.

[0029] According to any activated carbon purification system of the second aspect of the present invention, the activated carbon purification system comprises at least one of the following systems:

[0030] A feeder system, located at the inlet end of the feed cylinder, is used to convey the material to be purified into the feed cylinder, and the feed end of the feeder system is connected to the silo system.

[0031] A dust removal and purification system is used to extract the volatiles during the purification of materials in the rotary kiln and perform dust removal and purification.

[0032] A cooler system, located at the discharge end of the rotary kiln, is used to cool the purified material.

[0033] A steam generator system is provided, wherein steam is supplied to the rotary kiln through a pipeline to activate the gas generated during material purification, and the pipeline is equipped with an electric heating device and a heat preservation device.

[0034] A nitrogen delivery system is connected to a rotary kiln, a dust removal and purification system, a cooler system, and a feeder system via pipelines.

[0035] According to any activated carbon purification system of the second aspect of the present invention, the dust removal and purification system is installed at the inlet end of the feed cylinder and connected to the upper end of the feeder system, and the exhaust pipe of the dust removal and purification system is equipped with a variable frequency negative pressure fan and connected to the incinerator system.

[0036] The dust removal and purification system is also connected to a nitrogen injection system. The nitrogen injection system blows the filter components in the dust removal and purification system so that the material that is not completely pyrolyzed and purified on the filter components falls back into the feeder system and re-enters the rotary kiln.

[0037] According to any activated carbon purification system of the second aspect of the present invention, the feed end of the feeder system and the connection part between the dust collector system and the rotary kiln are provided with a first sealing device, which is an airbag packing sealing device.

[0038] According to any activated carbon purification system of the second aspect of the present invention, the cooler system is installed below the discharge port of the rotary kiln, and its connection is provided with a pneumatic valve, an air hammer and a corrugated compensation pipe. The cooler system includes an inner chamber and an outer chamber. The inner chamber is connected to the discharge port of the rotary kiln and is provided with a spiral for conveying materials. The outer chamber is connected to a circulating water inlet pipe on one side and to one end of the spiral shaft in the inner chamber through a pipe on the other side. The other end of the spiral shaft is connected to a circulating water outlet pipe.

[0039] A third aspect of the present invention also provides a multi-stage circulating axial partition activated carbon purification method, which employs any of the activated carbon purification systems described in the second aspect of the present invention, including the step of pyrolyzing and purifying the material using the rotary kiln.

[0040] Furthermore, the step of using a rotary kiln to pyrolyze and purify the material specifically includes:

[0041] When the rotary kiln rotates counterclockwise, the material enters the inner cylinder through the feed cylinder and is conveyed from left to right by the guide screw of the inner cylinder. Then, it enters the outer cylinder through the second window at the right end of the inner cylinder. The guide screw of the outer cylinder then conveys the material to the left end. Under the action of the first guide plate at the left end, the material is guided from the outer cylinder through the first window into the inner cylinder, thereby realizing the infinite circulation of the material between the inner and outer cylinders.

[0042] When the rotary kiln rotates clockwise, the material is conveyed from right to left by the guide screw in the inner cylinder and falls into the outer cylinder through the first guide plate at the left end. Then, the guide screw in the outer cylinder conveys the material to the second guide plate at the right end. Under the action of the second guide plate, the material in the outer cylinder is lifted and conveyed to the discharge cylinder. The guide screw in the discharge cylinder conveys the material to the discharge port, thus completing the discharge.

[0043] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0044] (1) This invention provides a multi-stage circulating axial partitioned rotary kiln for activated carbon purification. By optimizing the structure of the rotary kiln, the rotary kiln can be divided into four circulating reaction units by using the feed cylinder, discharge cylinder, inner cylinder, outer cylinder, guide screws with different rotation directions, and the cooperation of the first guide plate and the second guide plate. Therefore, the material to be purified can be circulated repeatedly in the rotary kiln as needed. Thus, without extending the length of the reaction zone and increasing the floor area of ​​the rotary kiln, the material can be fully pyrolyzed and purified, ensuring the purification effect and greatly improving the rigidity and stability of the equipment.

[0045] (2) The present invention can extract the volatiles during the purification of materials in the rotary kiln and remove dust and purify them by setting up a dust removal and purification system. Furthermore, the dust removal and purification system is installed at the inlet end of the feed cylinder and connected to the upper end of the feeder system. At the same time, a nitrogen blowing system is also set up to blow the filter components in the dust removal and purification system, thereby automatically cleaning the particulate matter on the filter components. This particulate matter falls back into the feeder system through the blowing of the nitrogen blowing system and re-enters the multi-stage multiplication rotary kiln system for pyrolysis purification, which helps to ensure the full purification of materials and ensures that there is no material waste.

[0046] (3) The dust removal and purification system of the present invention is equipped with a variable frequency negative pressure fan on the exhaust pipe. The volatile matter generated by the purification of materials in the rotary kiln is extracted to the dust removal and purification system for purification by the variable frequency negative pressure fan. The purified CO and H2 are transported to the incinerator system through the pipeline. High temperature flue gas is generated by combustion, which can supplement the heat of the whole system. The excess high temperature can be recovered as waste heat. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the overall structure of the activated carbon purification system according to an embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram of the feed end structure of the rotary kiln according to an embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of the installation structure of the first guide plate of the rotary kiln in an embodiment of the present invention;

[0050] Figure 4 This is a schematic diagram of the discharge end structure of the rotary kiln according to an embodiment of the present invention;

[0051] Figure 5 This is a schematic diagram of the installation structure of the second guide plate of the rotary kiln in an embodiment of the present invention.

[0052] Label Explanation:

[0053] 1. Silo system; 2. Feed inlet; 3. Discharge outlet; 4. Dust filter; 5. Rotary discharge valve; 6. First sealing device; 7. Feeder system; 8. Dust removal and purification system; 9. Nitrogen injection system; 10. Variable frequency negative pressure fan; 11. Incinerator system;

[0054] 12. Feed cylinder; 13. First guide plate; 14. Inner cylinder; 1401. First window; 1402. Second window; 15. Outer cylinder; 16. Discharge cylinder; 17. Insulation device; 18. Guide screw; 19. Lifting plate; 20. Second guide plate; 21. Gear ring; 22. Electric heating insulation device; 23. Motor; 24. Second sealing device; 25. Kiln tail hood;

[0055] 26. Air hammer; 27. Pneumatic valve; 28. Corrugated compensating pipe; 29. ​​Spiral; 30. Circulating water inlet pipe; 31. Circulating water outlet pipe; 32. Rotary discharge valve; 33. Inner chamber; 34. Outer chamber; 35. Cooler system; 36. Steam generator system; 37. Nitrogen delivery system. Detailed Implementation

[0056] Some embodiments of the present invention also provide a multi-stage circulating axially partitioned activated carbon purification system, which includes a silo system, a feeder system, a dust collector system, a rotary kiln system, a cooler system, a steam generator system, a nitrogen conveying system, and an incinerator system, wherein:

[0057] A discharge valve is provided between the silo system and the feeder system, and the feeder system is connected to the inlet of the rotary kiln system; the dust collector is installed on the feeder system, and both systems are equipped with electric heat tracing devices and heat preservation devices.

[0058] The steam generator system supplies steam to the rotary kiln system through pipelines, and the pipelines are equipped with electric heat tracing devices and heat preservation devices.

[0059] The incinerator system is installed at the rear end of the dust removal and purification system. It uses a variable frequency negative pressure fan that can be linked to the pressure inside the furnace to deliver air, so that the gas containing volatiles discharged from the dust removal and purification system can be fully combusted and the heat generated by the combustion can be used for waste heat recovery.

[0060] The nitrogen delivery system is connected to the dust collector system, rotary kiln system, cooler system and feeder system via pipelines.

[0061] The rotary kiln system is divided into four circulating reaction units by a feed cylinder, an inner cylinder, an outer cylinder, guide screws with different rotation directions, and two guide plates on the left and right. By adjusting the rotation direction, the material in the rotary kiln system can be circulated in multiple stages.

[0062] The activated carbon purified using the purification system of this invention can meet the needs of the high-end market. The purified activated carbon is particularly suitable as an electrode material for lithium-ion batteries, sodium-ion batteries, or supercapacitors. Furthermore, while pyrolyzing and purifying the material, it can significantly reduce the floor space and energy consumption of the purification system, and improve the rigidity and stability of the system.

[0063] To further understand the content of this invention, it will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0064] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0065] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances.

[0066] It should also be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate for the embodiments of this application described herein.

[0067] Combination Figure 1As shown, this embodiment of the invention provides a multi-stage circulating axially partitioned rotary kiln. The rotary kiln includes a feed cylinder 12, a rotary cylinder assembly, and a discharge cylinder 16 arranged sequentially along the axial direction. The rotary cylinder assembly includes an inner cylinder 14 and an outer cylinder 15 coaxially fitted together. The feed cylinder 12 is located at one end of the rotary cylinder assembly and is used to feed materials into the rotary cylinder assembly, such as activated carbon to be purified, for pyrolysis purification treatment of the activated carbon. The discharge cylinder 16 is located at the other end of the rotary cylinder assembly and is used to discharge the processed materials out of the rotary kiln.

[0068] For example, when using a rotary kiln to pyrolyze and purify activated carbon, existing technologies usually require extending the length of the reaction zone to ensure sufficient material reaction, resulting in a large equipment footprint, affecting the rigidity of the equipment and the cost-effectiveness of activated carbon purification.

[0069] To solve this technical problem and ensure the complete pyrolysis and purification of activated carbon without increasing the equipment footprint, in this embodiment of the invention, guide screws 18 are provided in the feed cylinder 12, discharge cylinder 16, inner cylinder 14, and outer cylinder 15. The guide screws 18 in the feed cylinder 12 and inner cylinder 14 are both right-handed, while the guide screws 18 in the discharge cylinder 16 and outer cylinder 15 are both left-handed. Furthermore, in conjunction with… Figures 2-5 As shown, in this embodiment of the invention, a first guide plate 13 is provided between the outer cylinder 15 and the inner cylinder 14 and near the end of the feed cylinder 12, and a second guide plate 20 is provided inside the outer cylinder 15 and near the end of the discharge cylinder 16. A first window 1401 is correspondingly machined on the cylinder wall of the inner cylinder 14 near the feed cylinder 12, and a second window 1402 is correspondingly machined on the cylinder wall of the inner cylinder 14 near the discharge cylinder 16.

[0070] The rotary kiln is divided into four circulating reaction units through the combined action of the feed cylinder, discharge cylinder, inner cylinder, outer cylinder, guide screws with different rotation directions, and the first and second guide plates. During feeding and normal operation, the kiln rotates counter-clockwise. Material enters the inner cylinder through the feed cylinder and is conveyed from left to right by the guide screws to the second guide plate on the right. The material then enters the outer cylinder through a second window in the inner cylinder and is conveyed to the first guide plate on the left by the guide screws. The first guide plate guides the material from the outer cylinder back into the inner cylinder, thus achieving an infinite circulation of material between the inner and outer cylinders. This allows for sufficient material reaction without increasing the equipment's footprint. An electric heating and insulation device 22 is installed on the outside of the outer cylinder to heat the material in both the inner and outer cylinders, promoting pyrolysis and purification.

[0071] After the material has undergone sufficient pyrolysis and purification reaction, the equipment is rotated clockwise. At this time, the material is conveyed from right to left by the guide screw in the inner cylinder, and then guided into the outer cylinder by the first guide plate at the left end. The guide screw in the outer cylinder then conveys the material to the second guide plate at the right end. The second guide plate lifts and conveys the material in the outer cylinder to the discharge cylinder. The guide screw in the discharge cylinder then conveys the material to the discharge port, thus completing the discharge.

[0072] As a further preferred embodiment, the two ends of the first guide plate 13 are fixedly connected to the outer wall of the inner cylinder 14 and the inner wall of the outer cylinder 15, respectively, and a plurality of first guide plates 13 are spaced apart along the circumference of the inner cylinder 14. The inner cylinder 14 has a plurality of first windows 1401 processed on its cylinder wall, and the plurality of first guide plates 13 and the plurality of first windows 1401 are arranged alternately along the circumference of the inner cylinder 14.

[0073] The number of the first guide plate 13 and the first window 1401 can be selected and determined according to the size of the rotary kiln, and the shape of the first guide plate 13 is not limited, as long as it can realize the transmission of materials between the inner and outer cylinders. In some preferred embodiments, the first guide plate 13 is an arc-shaped plate structure, and more preferably an arc-shaped quadrilateral structure.

[0074] Similarly, the outer cylinder 15 has a plurality of second guide plates 20 arranged circumferentially at intervals at one end near the discharge cylinder 16. The shape and number of the second guide plates 20 are not limited. For example, in some embodiments, the second guide plates 20 can be arc-shaped or L-shaped.

[0075] More preferably, the inner cylinder 14 has a plurality of second windows 1402 that are distributed circumferentially on the end wall of the inner cylinder 14 near the discharge cylinder 16, and the second windows 1402 are located on the inner side of the second guide plate 20, that is, the second guide plate 20 is located between the discharge cylinder and the second windows 1402.

[0076] In order to ensure that the material is fully heated and the purification reaction is fully carried out, in some embodiments, the area of ​​the inner cylinder 14 and the outer cylinder 15 in contact with the material is also provided with lifting plates 19, which can lift the material. The structure of the lifting plates 19 can directly adopt the existing structure, which will not be described in detail here.

[0077] Furthermore, both the feed cylinder 12 and the discharge cylinder 16 are provided with heat preservation devices 17 on their outer sides. A rolling ring is provided on the outer side of the heat preservation device of the feed cylinder, and the rolling ring is supported by a roller device. A toothed ring 21 is provided on the outer side of the heat preservation device of the discharge cylinder, and the toothed ring 21 is connected to the motor 23 for driving. The motor 23 can drive the equipment to rotate.

[0078] like Figure 1As shown, a kiln tail hood 25 is also provided at the discharge port of the discharge cylinder 16. A second sealing device 24 is provided between the kiln tail hood 25 and the outer wall of the discharge cylinder 16 to ensure that no material or gas escapes from the connection point during the rotation of the rotary kiln. The second sealing device 24 is preferably an airbag sealing device. At the same time, an explosion-proof manhole, a steam outlet nozzle, and a nitrogen inlet are also provided at the right end of the discharge cylinder 16 to facilitate the injection of steam and nitrogen into the equipment for material activation and reaction with CO2 inside the rotary kiln to generate CO and H2.

[0079] This invention also provides a multi-stage circulating axial partition activated carbon purification system, which includes:

[0080] A rotary kiln, used for pyrolysis purification of activated carbon, adopts the rotary kiln structure of any of the preceding embodiments;

[0081] The feeder system 7 is located at the inlet end of the feed cylinder 12 and is used to transport the material to be purified into the feed cylinder 12. The feeder system 7 is connected to the silo system 1.

[0082] Dust removal and purification system 8, which is used to extract the volatiles during the purification of materials in the rotary kiln and perform dust removal and purification.

[0083] Cooler system 35, located at the discharge end of the rotary kiln, is used to cool the purified material.

[0084] Steam generator system 36, which supplies steam into the rotary kiln through a pipeline to activate the gas generated during material purification, and the pipeline is equipped with an electric heating device and a heat preservation device.

[0085] And a nitrogen delivery system 37, which is connected to the rotary kiln, the dust collector system 8, the cooler system 35 and the feeder system 7 via pipelines.

[0086] The feeder system 7 preferably employs a screw conveyor, which uses a variable frequency motor to drive the screw shaft and precisely transport the material into the rotary kiln feed cylinder. The feeder system 7 is equipped with a first sealing device 6 to ensure that the conveyed material and its volatile components do not escape. The first sealing device 6 is preferably a packing seal.

[0087] Furthermore, the silo system is installed in front of the feeder system 7, with an inlet 2 at the top and an outlet 3 at the bottom. In some embodiments, the silo system is the end of the pneumatic material conveying system, and includes a dust filter 4 to remove dust from the pneumatically conveyed gas before discharging it from the system. More preferably, the silo system also includes a high-level sensor and a low-level sensor. When the high-level sensor is triggered, the pneumatic conveying stops; when the low-level sensor is triggered, the pneumatic conveying starts. The outlet of the silo system is equipped with a rotary discharge valve 5, which is driven by a motor to discharge material. The outlet of the rotary discharge valve is connected to the inlet of the feeder system 7, and a vibration device is installed above the outlet to prevent material bridging.

[0088] In a further preferred embodiment, the dust removal and purification system 8 is installed at the inlet end of the feed cylinder 12 and connected to the upper end of the feeder system 7. The exhaust pipe of the dust removal and purification system 8 is equipped with a variable frequency negative pressure fan 10 and is connected to the incinerator system 11. The dust removal and purification system 8 draws air outward through the variable frequency negative pressure fan 10, which can continuously purify the impurity gas after the rotary kiln pyrolysis purification, and transport the dust-removed and purified combustible gas to the incinerator system 11 for complete combustion. The high-temperature flue gas generated can supplement the heat of the entire system, and the excess high temperature can be recovered as waste heat.

[0089] Furthermore, the dust removal and purification system 8 is also connected to the nitrogen injection system 9. The nitrogen injection system 9 can spray the filter components in the dust removal and purification system 8 so that the material that is not completely pyrolyzed and purified on the filter components falls back into the feeder system and re-enters the rotary kiln for pyrolysis and purification. This helps to ensure the full reaction of the material and prevents material waste.

[0090] To ensure that no material or gas escapes from the connection point during the rotation of the rotary kiln, in some embodiments, the connection between the dust collector system 8 and the rotary kiln is also equipped with an airbag sealing device.

[0091] The cooler system 35 is installed below the discharge port of the rotary kiln, and its connection is equipped with a pneumatic valve 27, an air hammer 26, and a corrugated compensating pipe 28. In one implementation, the cooler system 35 includes an inner chamber 33 and an outer chamber 34. The inner chamber 33 is connected to the discharge port of the rotary kiln and contains a spiral 29 for conveying materials. The outer chamber 34 is connected to the circulating water inlet pipe 30 on one side and to one end of the spiral shaft inside the inner chamber 33 via a pipe on the other side. The other end of the spiral shaft is connected to the circulating water outlet pipe 32.

[0092] Specifically, the material is separated from the cooling water by the inner and outer chambers. The material is conveyed by a centrally driven screw. The circulating cooling water enters the outer shell through the circulating water inlet, first cooling the outer shell of the cooler, and then enters the interior of the screw conveyor system through pipes to cool the screw conveyor, thereby cooling the material. The cooled material is discharged through the circulating water outlet of the cooler system. A rotary discharge valve is provided at the material outlet to accurately unload the cooled material.

[0093] In some embodiments, the steam generator system converts water into steam, which is then introduced into the rotary kiln via pipes and steam outlet nozzles to activate the gas generated during material purification. The nitrogen delivery system can deliver nitrogen to the dust collector system for blowing the filter components; deliver nitrogen into the rotary kiln for activation with the gas generated during material purification; deliver nitrogen to the cooler system to displace internal air and prevent material oxidation; and deliver nitrogen to the airbag sealing device to provide high-pressure gas to the airbag.

[0094] This invention also provides a multi-stage circulating axial partition activated carbon purification method, using any of the above-mentioned activated carbon purification systems, including the following steps:

[0095] (1) The material is conveyed to the silo system by pneumatic conveying. The silo system is equipped with a dust removal filter to remove dust from the gas conveyed by pneumatic conveying before it is discharged from the system. The material enters the feeder system through the rotary discharge valve.

[0096] (2) After the material enters the feeder system, the system transports the material to the rotary kiln through the rotating spiral blades. Since the material is fine powder particles, a packing seal is provided at the connection between the spiral shaft and the shell of the feeder system to prevent the material from overflowing.

[0097] (3) After the material is conveyed to the rotary kiln through the feeder system, it is pyrolyzed and purified in the rotary kiln;

[0098] (4) After the material is collected by the kiln tail hood, it enters the cooler system by gravity. To prevent the material from bridging, an air hammer is installed at the connecting pipe to make the feeding of the cooler system smoother. After the material is cooled by the cooler system, it is discharged by rotating the discharge valve. The discharged material can then be packaged and transported.

[0099] The specific process of pyrolysis purification of materials using a rotary kiln is as follows:

[0100] During feeding and normal deheating and purification, the rotary kiln is controlled to rotate counterclockwise. At this time, the material enters the inner cylinder 14 through the feed cylinder 12 and is conveyed from left to right by the guide screw 18 of the inner cylinder 14. Then, it enters the outer cylinder 15 through the second window 1402 at the right end of the inner cylinder. The guide screw 18 of the outer cylinder 15 then conveys the material to the left end. Under the action of the first guide plate 13 at the left end, the material is guided from the outer cylinder through the first window 1401 into the inner cylinder 14, thereby realizing the infinite circulation of the material between the inner and outer cylinders.

[0101] After the material pyrolysis and purification are completed, the rotary kiln is controlled to rotate clockwise. At this time, the material will be conveyed from right to left through the guide screw 18 in the inner cylinder 14, and then guided into the outer cylinder through the first guide plate 13 at the left end. The guide screw 18 in the outer cylinder 15 will then convey the material to the second guide plate 20 at the right end. Under the action of the second guide plate 20, the material in the outer cylinder will be lifted and conveyed to the discharge cylinder 16. The guide screw in the discharge cylinder 16 will convey the material to the discharge port, thus completing the discharge.

[0102] Furthermore, during the pyrolysis purification process in the rotary kiln, volatiles and CO2 gas are generated. The steam generator system and nitrogen delivery system then supply steam and nitrogen to the rotary kiln, where they react with the CO2 inside to produce CO and H2. The volatiles, along with the generated CO and H2, are then drawn into the dust collector system by a variable frequency negative pressure fan. During this process, some material may be drawn out. The nitrogen blowing system within the dust collector system then shakes off the incompletely pyrolyzed material adhering to the filter components and onto the feeder system. This incompletely purified material is then reintroduced into the rotary kiln for pyrolysis purification, ensuring no material waste and that the purified material meets design requirements. The CO and H2 purified by the dust collector system are then piped to the incinerator system, where combustion generates high-temperature flue gas, which can supplement the overall system's heat. Excess heat can be recovered as waste heat.

[0103] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A multi-stage circulating shaft kiln for purification of activated carbon by axial zoning, characterized in that, The rotary kiln includes: A rotary cylinder assembly comprising an inner cylinder (14) and an outer cylinder (15) coaxially mounted. Feed cylinder (12), which is located at one end of the rotary drum assembly, is used to convey the material to be purified into the rotary drum assembly; And discharge cylinder (16), which is located at the other end of the rotary cylinder assembly and is used to convey the purified material out of the rotary kiln; Among them, the feed cylinder (12), the discharge cylinder (16), the inner cylinder (14) and the outer cylinder (15) are all equipped with guide screws (18), and the guide screws (18) of the feed cylinder (12) and the inner cylinder (14) are both right-handed, while the guide screws (18) of the discharge cylinder (16) and the outer cylinder (15) are both left-handed; A first guide plate (13) is provided between the outer cylinder (15) and the inner cylinder (14) and near the feed cylinder (12). A first window (1401) is correspondingly processed on the cylinder wall of the inner cylinder (14) near the feed cylinder (12). When the rotary kiln rotates counterclockwise, the material in the outer cylinder (15) is guided into the inner cylinder (14) through the first window (1401) via the first guide plate (13); when the rotary kiln rotates clockwise, the material in the inner cylinder (14) is guided into the outer cylinder (15) via the first guide plate (13). A second guide plate (20) is provided at one end of the outer cylinder (15) near the discharge cylinder (16). When the rotary kiln rotates clockwise, the material in the outer cylinder (15) is discharged into the discharge cylinder (16) through the second guide plate (20). A second window (1402) is correspondingly processed on the wall of the inner cylinder (14) near the discharge cylinder (16). When the rotary kiln rotates counterclockwise, the material in the inner cylinder (14) enters the outer cylinder (15) through the second window (1402).

2. The multi-stage, rotary kiln, axial zoned activated carbon purification system of claim 1, wherein, The two ends of the first guide plate (13) are fixedly connected to the outer wall of the inner cylinder (14) and the inner wall of the outer cylinder (15), and multiple first guide plates (13) are spaced apart along the circumference of the inner cylinder (14). The inner cylinder (14) has multiple first windows (1401) processed on its wall. Multiple first guide plates (13) and multiple first windows (1401) are arranged alternately along the circumference of the inner cylinder (14).

3. The multi-stage, circulating, axial zoned activated carbon purification rotary kiln according to claim 1, wherein, The outer cylinder (15) is provided with a plurality of second guide plates (20) that are spaced apart in the circumferential direction at one end near the discharge cylinder (16). The inner cylinder (14) has a plurality of second windows (1402) that are spaced apart along its circumference on one end of the cylinder wall near the discharge cylinder (16), and the second windows (1402) are located on the inner side of the second guide plate (20).

4. The rotary kiln for multi-stage circulating axial partition activated carbon purification according to any one of claims 1-3, characterized in that, The feed cylinder (12), discharge cylinder (16) and rotary cylinder assembly are all provided with heat preservation devices on their outer sides. A rolling ring is provided on the outer side of the heat preservation device of the feed cylinder, and the rolling ring is supported by a roller device. A toothed ring (21) is provided on the outer side of the heat preservation device of the discharge cylinder, and the toothed ring (21) is connected to the motor (23) for drive. The discharge port of the discharge cylinder (16) is provided with a kiln tail cover (25), and a second sealing device (24) is provided between the kiln tail cover (25) and the outer wall of the discharge cylinder (16).

5. A multi-stage circulating axial partition activated carbon purification system, characterized in that, include: The rotary kiln includes any one of claims 1-4.

6. The activated carbon purification system according to claim 5, characterized in that, The activated carbon purification system includes at least one of the following systems: The feeder system (7) is located at the inlet end of the feed cylinder (12) and is used to transport the material to be purified into the feed cylinder (12). The feed end of the feeder system (7) is connected to the silo system (1). Dust removal and purification system (8), the dust removal and purification system (8) is used to extract the volatiles during the purification of materials in the rotary kiln and remove dust and purify them; Cooler system (35), located at the discharge end of rotary kiln, is used to cool the purified material; Steam generator system (36) supplies steam to the rotary kiln through a pipeline to activate the gas generated during material purification, and the pipeline is equipped with an electric heating device and a heat preservation device. The nitrogen delivery system (37) is connected to the rotary kiln, the dust collector system (8), the cooler system (35) and the feeder system (7) through pipelines.

7. The activated carbon purification system of claim 6, wherein, The dust removal and purification system (8) is installed at the inlet end of the feed cylinder (12) and connected to the upper end of the feeder system (7). The exhaust pipe of the dust removal and purification system (8) is equipped with a variable frequency negative pressure fan (10) and connected to the incinerator system (11). The dust removal and purification system (8) is also connected to the nitrogen injection system (9). The nitrogen injection system (9) blows the filter components in the dust removal and purification system so that the material that is not completely pyrolyzed and purified on the filter components falls back into the feeder system and re-enters the rotary kiln.

8. The activated carbon purification system according to claim 6 or 7, characterized by The feed end of the feeder system and the connection between the dust collector system (8) and the rotary kiln are provided with a first sealing device (6), which is an airbag packing sealing device. The cooler system (35) is installed below the discharge port of the rotary kiln, and its connection is provided with a pneumatic valve (27), an air hammer (26) and a corrugated compensation pipe (28). The cooler system (35) includes an inner chamber (33) and an outer chamber (34). The inner chamber (33) is connected to the discharge port of the rotary kiln and is provided with a spiral (29) for conveying materials. The outer chamber (34) is connected to the circulating water inlet pipe (30) on one hand, and to one end of the spiral shaft in the inner chamber (33) through a pipe on the other hand. The other end of the spiral shaft is connected to the circulating water outlet pipe (32).

9. A multi-stage cyclic axial zoned activated carbon purification process characterized by, The activated carbon purification system according to any one of claims 5-8 includes the step of pyrolyzing and purifying the material using a rotary kiln.

10. The purification method according to claim 9, characterized in that, The step of using a rotary kiln to pyrolyze and purify the material specifically includes: When the rotary kiln rotates counterclockwise, the material enters the inner cylinder (14) through the feed cylinder (12) and is conveyed from left to right by the guide screw (18) of the inner cylinder (14). Then, it enters the outer cylinder (15) through the second window (1402) at the right end of the inner cylinder. The guide screw (18) of the outer cylinder (15) then conveys the material to the left end. Under the action of the first guide plate (13) at the left end, the material is guided from the outer cylinder through the first window (1401) into the inner cylinder (14), thereby realizing the infinite circulation of the material between the inner and outer cylinders. When the rotary kiln rotates clockwise, the material is conveyed from right to left by the guide screw (18) in the inner cylinder (14) and falls into the outer cylinder through the first guide plate (13) at the left end. Then, the guide screw (18) of the outer cylinder (15) conveys the material to the second guide plate (20) at the right end. Under the action of the second guide plate (20), the material in the outer cylinder is lifted and conveyed to the discharge cylinder (16). The guide screw in the discharge cylinder (16) conveys the material to the discharge port, thus completing the discharge.

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