Carbon nanotube production apparatus and system thereof

Abstract

This invention relates to the field of carbon nanotube production technology, specifically to a carbon nanotube production apparatus and system. The apparatus includes a reaction chamber with a main shaft rotatably mounted inside. From top to bottom, the main shaft is equipped with a gas distribution mechanism, a reaction mechanism, and a purification mechanism. A drive mechanism for rotating the main shaft is also located at the top of the reaction chamber. The gas distribution mechanism distributes various raw material gases participating in the reaction and modulates them into a pulsed gas flow. The reaction mechanism receives the pulsed gas flow and mixes the raw material gases to induce a contact reaction, generating reaction products containing carbon nanotubes. The purification mechanism centrifuges the reaction products to separate carbon nanotubes from impurities by density. The drive mechanism drives the gas distribution mechanism, reaction mechanism, and purification mechanism to operate synchronously, enabling continuous production of carbon nanotubes. This invention aims to improve the purity and batch stability of the reaction products, thereby obtaining higher quality carbon nanotube products.

Description

Technical Field

[0001] This invention relates to the field of carbon nanotube production technology, specifically to a carbon nanotube production apparatus and system. Background Technology

[0002] Carbon nanotubes (CNTs), as one-dimensional nanomaterials, have broad application prospects in fields such as lithium battery conductive agents, high-performance composite materials, semiconductor devices, and aerospace due to their unique tubular structure and excellent mechanical, electrical, and thermal properties. Currently, the mainstream methods for preparing carbon nanotubes mainly include arc discharge, laser ablation, and chemical vapor deposition (CVD).

[0003] Among existing preparation processes, the arc discharge method can obtain carbon nanotubes with high purity, but it has high reaction energy consumption, the product often contains a large number of metal particles and amorphous carbon impurities, the subsequent purification process is complex, and it is difficult to achieve continuous production. The laser ablation method prepares carbon nanotubes by bombarding a graphite target containing a catalyst with a high-energy laser. Although the product purity is high, the equipment is expensive, the energy consumption is huge, and it is limited by the size of the target material, making it difficult to carry out large-scale industrial applications.

[0004] Chemical vapor deposition (CVD) is considered the most promising method for industrialization due to its advantages such as simple operation, low cost, and controllable temperature. However, traditional CVD methods are usually carried out in fixed-bed or fluidized-bed reactors, which have problems such as catalyst particle agglomeration, uneven tube diameter distribution, and difficulty in efficiently separating products from impurities. As a result, the graphitization degree and purity of the final product often fail to meet the requirements of high-end applications.

[0005] Furthermore, most existing production processes separate gas reaction and product separation into independent unit operations, resulting in complex internal flow field control within the reactor, low utilization rate of raw material gases, and susceptibility to secondary contamination of the products during the reaction and collection process. Although some dispersion devices or improved reactor designs have emerged in existing technologies aimed at improving purity, these solutions often focus on optimizing a single step and lack systematic integration of gas proportioning, chemical reaction, and centrifugal fractionation purification, leading to room for improvement in production efficiency and product consistency.

[0006] Therefore, this invention proposes a carbon nanotube production apparatus and system to achieve high-quality, continuous, and clean production of carbon nanotubes. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a carbon nanotube production apparatus and system for improving the purity and batch stability of reaction products, thereby obtaining higher quality carbon nanotube products.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: A carbon nanotube production apparatus includes a reaction chamber, a main shaft rotatably fitted inside the reaction chamber, and a gas distribution mechanism, a reaction mechanism, and a purification mechanism arranged sequentially from top to bottom on the main shaft. A drive mechanism for driving the main shaft to rotate is also provided at the top of the reaction chamber.

[0009] The gas distribution mechanism is used to distribute the various raw material gases participating in the reaction and modulate the raw material gases into a pulsed gas flow; the reaction mechanism is used to receive the pulsed gas flow and mix the raw material gases to produce a contact reaction to generate reaction products containing carbon nanotubes; the purification mechanism is used to centrifuge the reaction products to separate carbon nanotubes from impurities according to density.

[0010] The drive mechanism is used to drive the gas distribution mechanism, reaction mechanism and purification mechanism to operate synchronously, so as to realize the continuous production of carbon nanotubes.

[0011] The technical principles of the above solution are as follows:

[0012] The main shaft is rotated by a drive mechanism, synchronizing the operation of the gas distribution mechanism, reaction mechanism, and purification mechanism. The gas distribution mechanism modulates the carbon source and the carrier gas containing the catalyst into a pulsed gas flow. After entering the reaction mechanism, the pulsed gas flow is fully mixed under the action of rotation, resulting in a contact reaction that promotes the uniform growth of carbon nanotubes on the catalyst. The reaction products enter the purification mechanism under the action of gravity and gas flow, where the centrifugal force generated by the high-speed rotation of the main shaft is used to separate the carbon nanotubes, catalyst impurities, and amorphous carbon according to their density differences.

[0013] The above approach has the following beneficial effects:

[0014] 1. This scheme achieves this by coaxially aligning and synchronously rotating the gas distribution mechanism, reaction mechanism, and purification mechanism. The gas distribution mechanism modulates the raw material gas into a pulsed gas flow, ensuring a periodic supply of carbon source and carrier gas to match the nucleation and growth stages of carbon nanotubes. The reaction mechanism generates turbulence under rotation, combined with a uniform temperature field distribution, reducing pipe diameter inconsistencies and structural defects caused by excessive local temperature differences, thereby improving the purity and batch stability of the reaction products.

[0015] 2. The purification mechanism in this scheme utilizes the centrifugal force generated by the high-speed rotation of the main shaft to separate carbon nanotubes, catalyst impurities, and amorphous carbon according to their density differences. Compared with traditional acid washing or single sieving methods, this avoids damage to the carbon nanotube structure caused by chemical reagents while simultaneously removing impurities. Components of different densities are discharged separately, ensuring separation efficiency and reducing product loss during the purification process, thereby obtaining higher quality carbon nanotube products.

[0016] 3. This solution uses a drive mechanism to synchronously operate the main shaft and other mechanisms. The raw material gas is modulated by the gas distribution mechanism before entering the reaction mechanism, and the reaction products enter the purification mechanism for separation. The entire process requires no manual intervention. The interconnected links between each stage reduce waiting and switching times between processes in traditional equipment, increase output per unit time, and reduce batch quality fluctuations caused by manual operation.

[0017] Furthermore, the drive mechanism includes a controller and a drive component, with the controller and drive component connected by signals; the drive component is fixedly connected to the outer top wall of the reaction chamber, and the output shaft of the drive component is coaxially fixedly connected to the main shaft.

[0018] Beneficial effects: The controller and drive unit are connected by signal, allowing for precise control of the drive unit's operation; the drive unit is fixed to the top of the reaction chamber and its output shaft is coaxially connected to the main shaft, ensuring stable power transmission. The combination of these two components allows the main shaft to operate as needed, guaranteeing the effective execution of subsequent operations, thereby improving production stability and product quality.

[0019] Furthermore, the gas distribution mechanism includes a gas distribution plate fixedly connected to the upper part of the main shaft, on which several throttling grooves are opened; several storage cavities for conveying raw materials are fixedly connected to the outer wall of the reaction chamber, and each storage cavity is connected to a transmission pipe at its top, with the end of the transmission pipe away from the storage cavity connected to the top of the reaction chamber; a pressure reducing valve for reducing gas pressure and a mass flow meter for controlling gas flow are also provided on the communication path between the transmission pipe and the reaction chamber, and the mass flow meter is connected to the controller signal.

[0020] Beneficial effects: By using a rotating gas distribution plate in conjunction with a transmission pipe, the raw material gas is modulated into a pulsed gas flow, promoting uniform mixing and optimizing reaction kinetics. Combined with a mass flow meter and controller, precise metering is achieved, ensuring stable gas ratios and improving the growth rate, structural consistency, and product purity of carbon nanotubes.

[0021] Furthermore, the reaction mechanism includes a spiral fin fixedly connected to the middle of the main shaft, an inner cylinder fixedly connected to the inner wall of the reaction chamber, a throttling groove communicating with the inner cylinder, and the spiral fin located inside the inner cylinder; a segmented heater is also fitted on the outer wall of the inner cylinder, and several temperature sensors are fixedly connected to the inner wall of the inner cylinder; the controller is used to acquire the temperature signal emitted by the temperature sensor and control the operation of the segmented heater based on the temperature signal.

[0022] Beneficial effects: The rotating helical fins enhance airflow mixing within the inner cylinder, improving reaction efficiency; the segmented heater, combined with a temperature sensor, enables precise temperature control in different zones, ensuring a stable reaction gradient. This design effectively reduces localized overheating or temperature unevenness, improves the crystallinity, structural uniformity, and product purity of carbon nanotubes, and guarantees the quality of continuous production.

[0023] Furthermore, the purification mechanism includes several screens fixedly connected to the lower part of the main shaft. Differential bearings are provided at the connection between the screens and the main shaft, and the screen apertures increase from top to bottom. Several sealing rings for filling gaps are also fixedly connected to the inner wall of the reaction chamber, and the screens rotate in cooperation with the sealing rings. Several flow ports are opened at the bottom of the inner cylinder, and each flow port is equipped with an elastic valve. The screens divide the bottom of the reaction chamber into several layers, and each layer is provided with a collection port, which is connected to a buffer silo for storing different products.

[0024] Beneficial effects: The purification mechanism utilizes a differential rotating screen to classify the product, combined with a flexible valve and layered collection design, effectively separating carbon nanotubes and impurities. This structure not only improves purification efficiency and product purity but also enables continuous online collection of products of various specifications, optimizing the production process and reducing subsequent processing costs.

[0025] Furthermore, a carbon nanotube production system includes a thermal field control module, a gas supply module, a staged purification module, a continuous conveying module, and a central control module.

[0026] The thermal field control module is connected to the temperature sensor and the segmented heater to collect temperature data in the reaction chamber in real time and transmit the temperature data to the central control module.

[0027] The gas supply module is used to provide pulsed airflow into the reaction chamber using the throttling groove of the gas distribution plate, and to record the pulse waveform parameters and transmit the pulse waveform parameters to the central control module.

[0028] The fractionation and purification module is used to centrifuge and fractionate the reaction products, monitor the purity data of the separated products in real time, and transmit the purity data to the central control module.

[0029] The continuous conveying module is used to switch the conveying path of the reaction products according to the instructions of the central control module;

[0030] The central control module drives the gas supply module to adjust the pulse waveform parameters based on the received temperature data, predicts the product characteristics based on the pulse waveform parameters and adjusts the rotation speed of the graded purification module, and drives the continuous conveying module to collect qualified products or circulate unqualified products back based on the purity data.

[0031] Beneficial effects: By optimizing reaction conditions through the linkage of thermal field and gas path, predicting product characteristics using pulse waveforms and adjusting fractionation speed, and automatically screening or refluxing based on purity data, this design can further improve the growth efficiency, structural uniformity, and product yield of carbon nanotubes, ensuring continuous high-quality production.

[0032] Furthermore, the temperature measurement points of the thermal field control module are evenly distributed along the axial and circumferential directions of the reaction chamber; the segmented heater is independently controlled by the central control module and is used to compensate for heating in local areas based on the temperature data distribution characteristics of the measurement points.

[0033] The central control module identifies the temperature data distribution characteristics and controls the proportion of hydrogen or carbon source in the pulsed gas flow of the gas supply module based on these characteristics; and the pulse waveform parameters are matched with the gas residence time in the reaction chamber.

[0034] Beneficial effects: By using multi-point temperature measurement and segmented heating to compensate for local temperature differences, and by adjusting the ratio of hydrogen to carbon source in the pulse gas path according to temperature distribution, the gas flow composition is matched with the thermal field space, effectively reducing the temperature difference in the reaction zone and improving the uniformity of carbon nanotube diameter and structural consistency during growth.

[0035] Furthermore, the central control module has a built-in empirical correlation model between pulse waveform parameters and the aspect ratio of carbon nanotubes. In the empirical correlation model, the pulse waveform parameters are positively correlated with the average aspect ratio.

[0036] Based on the pulse waveform parameters and duty cycle recorded by the gas supply module, the central control module predicts the average aspect ratio and impurity content of the current batch of reaction products through an empirical correlation model, and sends speed adjustment commands to the staged purification module accordingly.

[0037] Beneficial effects: By analyzing pulse parameters and duty cycle in real time, the average aspect ratio and impurity level of carbon nanotubes can be predicted in advance, and the rotation speed of the fractionation and purification module can be optimized accordingly. This effectively reduces separation deviations caused by parameter lag in traditional post-processing, improves the fractionation accuracy of products of different specifications, product consistency, and overall production efficiency.

[0038] Furthermore, the grading and purification module also includes a particle size analyzer installed on the screen; the continuous conveying module includes a screw conveyor and a pneumatic conveyor, which are respectively connected to a buffer silo, which includes a qualified product silo, a purified product silo, and a circulating return silo.

[0039] When the particle size analyzer detects that the purity data of the reaction product in one of the sieve layers reaches the preset threshold, the central control module drives the screw conveyor to transport the reaction product to the qualified product silo.

[0040] When the purity data does not reach the preset threshold, the pneumatic conveyor is activated to start the circulation backflow, sending the substandard product back to the inlet of the classification and purification module for secondary separation.

[0041] Beneficial effects: By integrating a particle size analyzer, product purity can be determined and a differentiated conveying strategy can be implemented: qualified products are directly stored in the warehouse, while substandard products are pneumatically conveyed back for secondary separation. This design not only enables automated product grading but also reduces ineffective energy consumption and improves the final purity, yield, and production continuity of carbon nanotubes.

[0042] Furthermore, the central control module is also used to associate and store the purity data fed back by the graded purification module with the corresponding pulse waveform parameters and temperature data distribution characteristics, and to optimize the empirical association model. Based on the optimized empirical association model, the pulse waveform adjustment command and centrifugal speed adjustment command for the next production batch are adjusted.

[0043] Beneficial effects: By continuously correlating and storing multi-dimensional data such as purity, pulse waveform, and temperature distribution, the system can continuously revise the empirical correlation model using historical batch feedback, achieving iterative optimization of the control strategy. This mechanism enhances the system's adaptability to complex reaction environments, ensuring that the production quality of carbon nanotubes continuously improves over time. Attached Figure Description

[0044] Figure 1 This is an isometric view of the carbon nanotube production apparatus of the present invention.

[0045] Figure 2 For the present invention Figure 1 The side sectional view in the middle.

[0046] Figure 3 For the present invention Figure 2 Axonometric view of the installation of the spiral fins.

[0047] Figure 4 This is a structural frame connection diagram of each module in the carbon nanotube production system of the present invention.

[0048] The reference numerals in the accompanying drawings include: 1. Reaction chamber; 2. Main shaft; 3. Drive component; 4. Gas distribution plate; 5. Storage chamber; 6. Spiral fins; 7. Inner cylinder; 8. Segmented heater; 9. Screen; 10. Differential bearing; 11. Flexible valve; 12. Buffer hopper. Detailed Implementation

[0049] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0052] The following detailed description illustrates the specific implementation method:

[0053] Example 1:

[0054] As attached Figures 1-3 As shown: A carbon nanotube production apparatus includes a reaction chamber 1, inside which a main shaft 2 is rotatably mounted. The main shaft 2 is sequentially equipped with a gas distribution mechanism, a reaction mechanism, and a purification mechanism from top to bottom. A drive mechanism for rotating the main shaft 2 is also provided at the top of the reaction chamber 1. In this embodiment, the upper and middle parts of the reaction chamber 1 are cylindrical, while its bottom is conical, and the length and diameter of the upper part are smaller than those of the middle part.

[0055] The gas distribution mechanism is used to distribute the various raw material gases participating in the reaction and modulate the raw material gases into a pulsed gas flow; the drive mechanism is used to drive the gas distribution mechanism, reaction mechanism and purification mechanism to operate synchronously, so as to realize the continuous production of carbon nanotubes.

[0056] The drive mechanism includes a controller and a drive component 3, with the controller and drive component 3 connected by signals. The drive component 3 is fixedly connected to the outer top wall of the reaction chamber 1, and its output shaft is coaxially fixedly connected to the main shaft 2. In this embodiment, the drive component 3 is a variable frequency motor, and the controller can be one or more of a PLC, CPU, or microcontroller.

[0057] Combination Figure 2As shown, the gas distribution mechanism includes a gas distribution plate 4 bolted to the upper part of the main shaft 2. The gas distribution plate 4 has several throttling grooves. In this embodiment, the throttling grooves are spiral or involute. Several storage cavities 5 for conveying raw materials are bolted to the outer wall of the reaction chamber 1. The top of each storage cavity 5 is connected to a transmission pipe. The end of the transmission pipe away from the storage cavity 5 is connected to the top of the reaction chamber 1. A pressure reducing valve for reducing gas pressure and a mass flow meter (MFC) for controlling gas flow are also provided on the communication path between the transmission pipe and the reaction chamber 1. The mass flow meter is connected to the controller signal.

[0058] In this embodiment, the storage chamber 5 includes a carbon source cylinder and a carrier gas cylinder. The carbon source mainly includes ethylene, methane, or acetylene; the carrier gas mainly includes hydrogen, nitrogen, or argon. Both the carbon source cylinder and the carrier gas cylinder are supplied in the form of high-pressure gas cylinders. The catalyst can be a liquid catalyst precursor (such as ferrocene dissolved in benzene or toluene), injected through a micro-injection pump. The outlet of the micro-injection pump is connected to the top of the reaction chamber 1. Before entering the reactor, the liquid precursor is converted into vapor by a vaporizer (heated to 150-200°C), and the vapor is mixed with the carbon source / carrier gas before entering the reaction chamber 1. In some other embodiments, a gaseous catalyst precursor (such as iron carbonyl gas) can also be used, which is also delivered in the form of high-pressure gas cylinders.

[0059] Specifically, when raw material gas needs to be transported, the drive unit 3 (variable frequency motor) receives the speed command from the controller (PLC, CPU, or microcontroller), and the output shaft of the drive unit 3 drives the main shaft 2 to rotate coaxially. When the main shaft 2 rotates, the gas distribution plate 4 fixed on the upper part of the main shaft 2 rotates synchronously. The spiral or involute throttling groove on the gas distribution plate 4 moves periodically relative to the fixed gas outlet at the top of the reaction chamber 1, thereby modulating the continuously input raw material gas into a pulsed airflow.

[0060] Carbon source cylinders and carrier gas cylinders are supplied in high-pressure gaseous form. The gas is depressurized to the required process pressure by a pressure reducing valve, and then the flow rate is controlled by a mass flow meter (MFC) before being transported to the top of reaction chamber 1 via a transmission pipe. Liquid catalyst precursor (such as ferrocene solution) is quantitatively injected by a micro-injection pump, heated to 150-200℃ by a vaporizer and converted into vapor, which mixes with the carbon source and carrier gas before entering the top of reaction chamber 1 together. The mixed gas forms a periodically on-off pulsed gas flow under the action of the throttling groove of the gas distribution plate 4. The pulse frequency and duty cycle are determined by the rotational speed of the main shaft 2 and the shape and distribution of the throttling groove.

[0061] The reaction mechanism is used to receive pulsed gas flow and mix the raw material gases to produce a contact reaction, thereby generating reaction products containing carbon nanotubes; the reaction mechanism includes a spiral fin 6 (such as a spiral fin 6 bolted to the middle of the main shaft 2) Figure 3As shown, the inner wall of the reaction chamber 1 is bolted to an inner cylinder 7, and a throttling groove communicates with the inner cylinder 7. The spiral fins 6 are located inside the inner cylinder 7. A segmented heater 8 is also fitted onto the outer wall of the inner cylinder 7, and several temperature sensors are screwed to the inner wall of the inner cylinder 7. A controller is used to acquire temperature signals from the temperature sensors and control the operation of the segmented heater 8 based on these temperature signals. In some preferred embodiments, the catalyst precursor can be pre-loaded into a carrier, such as by pre-coating the catalyst onto the inner cylinder 7 or the spiral fins 6, allowing gas to flow over its surface for growth.

[0062] Specifically, during the reaction stage, the drive unit 3 is set to a low speed range of 5-20 rpm. The main shaft 2 rotates continuously under the drive of the drive unit 3, and the spiral fins 6 fixed in the middle of the main shaft 2 rotate synchronously inside the inner cylinder 7. The pulsed airflow, modulated by the gas distribution mechanism, enters the inner cylinder 7 from the top of the reaction chamber 1. Under the action of the rotating spiral fins 6, the airflow no longer maintains a laminar flow state, but flows along a spiral path and forms turbulence. This turbulence promotes thorough mixing of the carbon source, carrier gas, and catalyst vapor (or gaseous catalyst), and uniformly washes over the wall of the inner cylinder 7 and the surface of the spiral fins 6.

[0063] The segmented heaters 8 on the outer wall of the inner cylinder 7 heat the inner cylinder 7 according to a preset process temperature (usually 600-1200℃). Multiple temperature sensors fixed to the inner wall of the inner cylinder 7 monitor the temperature at different locations in real time and transmit the temperature signals to the controller. The controller identifies the distribution characteristics of low-temperature or high-temperature zones in the temperature data and adjusts the output power of each segment heater to achieve local temperature compensation, making the temperature distribution inside the inner cylinder 7 more uniform.

[0064] Under uniform temperature and turbulent conditions, the catalyst (in vapor form or pre-coated on the surface of the inner cylinder 7 / spiral fins 6) catalyzes the decomposition of the carbon source gas, and carbon atoms are deposited and grown on the catalyst particles or surface to form carbon nanotubes. If the catalyst is pre-coated on the inner wall of the inner cylinder 7 or the surface of the spiral fins 6, the rotating spiral fins 6 drive the gas to continuously scour the coating layer, promoting the growth of carbon nanotubes from the surface and allowing them to peel off and be carried away by the airflow, thus achieving continuous growth.

[0065] The solid product containing carbon nanotubes generated by the reaction, along with unreacted gas and byproducts, moves downwards under the influence of gravity and airflow, entering the subsequent purification mechanism. The entire process achieves enhanced gas-solid mixing, uniform temperature field, and continuous growth of carbon nanotubes, providing a uniform and stable source of products for subsequent fractionation and separation.

[0066] The purification mechanism is used to centrifuge the reaction products to separate carbon nanotubes from impurities by density. The purification mechanism includes several screens 9 bolted to the lower part of the main shaft 2. Differential bearings 10 are provided at the connection points between the screens 9 and the main shaft 2. The aperture of the screens 9 increases sequentially from top to bottom; in this embodiment, the aperture of the screens 9 is 5μm, 20μm, or 50μm. Several sealing rings for filling gaps are also fixedly bonded to the inner wall of the reaction chamber 1, and the screens 9 rotate in conjunction with the sealing rings. Several flow ports are opened at the bottom of the inner cylinder 7, and each flow port is equipped with an elastic valve 11. In this embodiment, the elastic valve 11 is configured such that when the weight of the accumulated material (i.e., gravity G=mg) exceeds the elastic preload Fk, its valve disc is automatically pushed downwards. The screens 9 divide the bottom of the reaction chamber 1 into several layers, each layer having a collection port connected to a buffer hopper 12 for storing different products. In this embodiment, the sealing rings are used to block the reaction products, preventing them from falling into the lower layers through the gaps.

[0067] Specifically, the main shaft 2 rotates continuously under the drive of the drive component 3. The multi-layer screen 9, fixed at the lower part of the main shaft 2, is connected to the main shaft 2 through a differential bearing 10, realizing differential rotation between the screen 9 and the main shaft 2 (relative speed difference of 1°-3°). The bottom of the inner cylinder 7 is provided with multiple flow ports, and each flow port is equipped with an elastic valve 11 (normally closed). The mixture of carbon nanotubes, catalyst particles, amorphous carbon, etc. generated by the reaction mechanism accumulates above the elastic valve 11 under the push of gravity and airflow. When the weight of the accumulated material exceeds the spring preload, the valve automatically opens downward, and the mixture falls into the purification area below by gravity.

[0068] After the mixture enters the purification zone, during the refining stage, the drive unit 3 is set to a high-speed range of 800-1500 rpm. As the screen 9 rotates at high speed with the main shaft 2, centrifugal force is generated. Components of different densities migrate under the action of centrifugal force: the densest catalyst metal particles are thrown to the bottom screen 9 (largest pore size, e.g., 50 μm) and slide down the conical wall to the corresponding collection port; medium-density carbon nanotubes are suspended in the middle layer screen 9 (pore size 20 μm) and guided to the corresponding collection port; the least dense amorphous carbon and extremely fine particles are carried by the airflow to the top layer (pore size 5 μm). The differential bearing 10 creates a slight speed difference between the screen 9 and the main shaft 2, preventing material accumulation or blockage on the screen 9 and enhancing the screening effect.

[0069] Each layer of sieves 9 divides the bottom of the reaction chamber 1 into multiple independent layered spaces. Each layer is equipped with a collection port, which is connected to the corresponding buffer hopper 12 via a pipe. The different separated products enter their respective buffer hoppers 12, achieving the physical separation of carbon nanotubes and impurities.

[0070] In this embodiment, the elastic valve 11 opens automatically by the gravity of the material itself, without the need for external sensors or actuators, thus connecting the reaction and purification processes. After entering the purification zone, the centrifugal force generated by the rotation of the main shaft 2 takes over from gravity to complete the classification, forming a continuous power transmission of gravity sedimentation and centrifugal sorting.

[0071] The rotational speed of spindle 2 is adjusted in real time by the controller based on pulse waveform parameters (frequency and duty cycle). When the pulse frequency is high (indicating a large aspect ratio of the product), spindle 2 can increase its speed to enhance centrifugal force, ensuring that carbon nanotubes with large aspect ratios can be effectively separated; when the duty cycle is low (indicating fewer impurities), spindle 2 can appropriately reduce its speed to reduce product loss. This feedforward adjustment enables the purification mechanism to achieve a linkage response with the gas distribution and reaction mechanisms in terms of process parameters.

[0072] The differential rotation between the screen 9 and the main shaft 2 subjects the material to periodic shearing force on the screen 9, preventing highly viscous or long fibrous carbon nanotubes from entangled in the screen 9 and ensuring a continuous and stable separation process. Products of different densities fall into their corresponding stratified collection ports, eliminating the need for additional sorting devices and simplifying the device structure. Each buffer bin 12 can be further processed based on purity data. Through the above design, the purification mechanism can achieve efficient and continuous physical classification separation without human intervention, thereby improving the purity and yield of carbon nanotubes.

[0073] Example 2:

[0074] As attached Figure 4 As shown, the difference from Example 1 is that this example also provides a carbon nanotube production system, including a thermal field control module, a gas supply module, a staged purification module, a continuous conveying module, and a central control module; each module is communicatively connected to the central control module, forming a data synchronization bus; the specific functions of the modules are as follows:

[0075] The thermal field control module is connected to the temperature sensor and the segmented heater 8 to collect temperature data in the reaction chamber 1 in real time and transmit the temperature data to the central control module.

[0076] The gas supply module is used to provide pulsed airflow to the reaction chamber 1 using the throttling groove of the gas distribution plate 4, and to record the pulse waveform parameters and transmit the pulse waveform parameters to the central control module.

[0077] Among them, the temperature measurement points of the thermal field control module are evenly distributed along the axial and circumferential directions of the reaction chamber 1, and there are no less than 12 temperature measurement points; the segmented heater 8 is independently controlled by the central control module and is used to compensate for heating of local areas according to the temperature data distribution characteristics of the temperature measurement points.

[0078] The central control module identifies the distribution characteristics of low-temperature and high-temperature zones in the temperature data. When the temperature data distribution characteristics are consistent with those of the low-temperature zone, the control gas supply module increases the proportion of hydrogen in the pulsed gas flow. When the temperature data distribution characteristics are consistent with those of the high-temperature zone, the control gas supply module increases the proportion of carbon source in the pulsed gas flow, and the pulse waveform parameters are matched with the gas residence time in reaction chamber 1.

[0079] Specifically, temperature data is collected in real time at each temperature measuring point. The central control module processes the collected temperature data to identify low-temperature zones (areas below the lower limit of the target temperature, e.g., below 695℃ when the target temperature is 700℃) and high-temperature zones (areas above the upper limit of the target temperature, e.g., exceeding 705℃). Simultaneously, the central control module calculates the residence time required for gas in reaction chamber 1 to travel from the inlet through each temperature measuring point to the outlet, establishing a correspondence between abnormal temperature areas and the time window for gas to reach those areas.

[0080] Based on temperature distribution characteristics, the central control module sends adjustment commands to the gas supply module: when a low-temperature zone is detected at a certain axial position, the central control module calculates the time window for gas to reach that low-temperature zone. Within the pulse cycle corresponding to this time window, it instructs the mass flow meter to increase the hydrogen ratio (e.g., increasing the hydrogen ratio from 40% to 60%). The high thermal conductivity of hydrogen helps transfer heat from the high-temperature zone to the low-temperature zone, achieving auxiliary heating.

[0081] When a high-temperature zone is detected at a certain axial position, the central control module calculates the time window for the gas to reach that zone. Within the pulse cycle corresponding to this time window, it instructs the mass flow meter to increase the carbon source ratio (e.g., increasing the ethylene ratio from 30% to 50%). The carbon source gas undergoes an endothermic decomposition reaction at high temperature, consuming excess heat and achieving auxiliary cooling.

[0082] The central control module adjusts the pulse frequency and duty cycle of the mass flow meter to match the pulse frequency with the gas residence time in reaction chamber 1. Specifically, the pulse period is set to an integer fraction of the time required for the gas to flow from the inlet to the outlet, ensuring that the high-proportion hydrogen segment or high-proportion carbon source segment of each pulse waveform precisely covers the gas residence time window of the corresponding temperature anomaly region. In this way, gas molecules are in a hydrogen-rich state when they reach the low-temperature region and in a carbon-rich state when they reach the high-temperature region, achieving spatial coupling between the thermal field and the gas field.

[0083] The above process continues throughout the carbon nanotube growth. Temperature changes are reported in real time at each temperature measurement point, and the central control module dynamically adjusts the pulse waveform parameters based on changes in temperature distribution. When the temperature distribution becomes more uniform, the pulse waveform gradually returns to the baseline ratio; when a new temperature anomaly occurs, the adjustment is triggered again.

[0084] The fractionation and purification module is used to centrifuge and fractionate the reaction products, monitor the purity data of the separated products in real time, and transmit the purity data to the central control module.

[0085] The continuous conveying module is used to switch the conveying path of the reaction products according to the instructions of the central control module.

[0086] The grading and purification module also includes a particle size analyzer installed on the screen 9; the continuous conveying module includes a screw conveyor and a pneumatic conveyor, which are respectively connected to the buffer silo 12. The buffer silo 12 includes a qualified product silo, a purified product silo, and a circulating return silo.

[0087] When the particle size analyzer detects that the purity data of the reaction product within one of the sieve layers 9 reaches the preset threshold, the central control module drives the screw conveyor to transport the reaction product to the qualified product silo. When the purity data does not reach the preset threshold, the pneumatic conveyor is driven to start the circulation backflow, sending the substandard product back to the inlet of the classification and purification module for secondary separation.

[0088] Specifically, after the elastic valve 11 at the bottom of the inner cylinder 7 of the reaction chamber 1 is opened, the mixture containing carbon nanotubes, catalyst metal particles, and amorphous carbon falls into the purification area below by gravity. The main shaft 2 drives the multi-layer screens 9 (pore sizes of 5μm, 20μm, and 50μm) to rotate at high speed (800-1500 rpm), generating a centrifugal force field. Components of different densities migrate radially under the action of centrifugal force: the bottom screen (50μm) retains the densest catalyst particles, the middle screen (20μm) retains carbon nanotubes, and the top screen (5μm) retains amorphous carbon and extremely fine particles. Each screen 9 has an independent collection port, and the separated products enter the corresponding collection channels.

[0089] A particle size analyzer is installed at the collection port of sieve 9 located in the carbon nanotube layer. The particle size analyzer continuously collects particle size distribution data of the flowing product and calculates the purity of the carbon nanotubes (i.e., the proportion of carbon nanotube mass to the total solid mass) using a built-in algorithm (such as laser diffraction or image analysis). The purity data is transmitted to the central control module in real time. The central control module compares the received purity value with a preset threshold (e.g., 99.5%).

[0090] When the particle size analyzer detects that the purity data reaches or exceeds the preset threshold (e.g., ≥99.5%), the central control module determines that this portion of the product is qualified. The central control module sends a start command to the screw conveyor in the continuous conveying module, switches the corresponding three-way valve, and conveys the qualified product from the collection port to the qualified product silo. When the particle size analyzer detects that the purity data does not reach the preset threshold (e.g., <99.5%), the central control module determines that this portion of the product is substandard. The central control module does not start the screw conveyor, but instead sends a start command to the pneumatic conveyor. The pneumatic conveyor (usually using compressed air or nitrogen as the conveying medium) conveys the material back to the inlet of the classification and purification module, mixes it with new reaction products, and then performs centrifugal classification again.

[0091] The central control module drives the gas supply module to adjust the pulse waveform parameters based on the received temperature data, predicts the product characteristics based on the pulse waveform parameters and adjusts the rotation speed of the graded purification module, and drives the continuous conveying module to collect qualified products or circulate unqualified products back based on the purity data.

[0092] The central control module has a built-in empirical correlation model between pulse waveform parameters and the aspect ratio of carbon nanotubes. In the empirical correlation model, the pulse waveform parameters are positively correlated with the average aspect ratio (correlation coefficient R²>0.92).

[0093] Based on the pulse waveform parameters and duty cycle recorded by the gas supply module, the central control module predicts the average aspect ratio and impurity content of the current batch of reaction products through an empirical correlation model, and sends speed adjustment commands to the staged purification module accordingly.

[0094] The central control module is also used to associate and store the purity data fed back by the graded purification module with the corresponding pulse waveform parameters and temperature data distribution characteristics, and to optimize the empirical association model. Based on the optimized empirical association model, the pulse waveform adjustment command and centrifugal speed adjustment command for the next production batch are adjusted.

[0095] Specifically, during the reaction, the central control module records the pulse waveform parameters output by the gas supply module in real time, including pulse frequency f, duty cycle D, and amplitude changes. The central control module has a built-in empirical correlation model, established based on historical experimental data, describing the positive correlation between pulse frequency and the average aspect ratio of carbon nanotubes. In practice:

[0096] When the central control module detects that the pulse frequency of the current batch is higher than a preset threshold (e.g., >5 Hz), the model predicts that the product has a larger aspect ratio. This means that the long, fibrous carbon nanotubes require greater centrifugal force to migrate effectively during centrifugation. Based on this, the central control module sends a speed increase command (e.g., from 800 rpm to 1000 rpm) to the variable frequency centrifuge in the fractionation purification module to enhance the separation force and prevent the carbon nanotubes with large aspect ratios from being mistakenly thrown into the impurity layer.

[0097] When the central control module detects that the pulse duty cycle is below a preset threshold (e.g., <30%, indicating a high hydrogen content), the empirical correlation model predicts that there are few catalyst impurities remaining (because hydrogen has a cleaning effect on the catalyst surface). At this point, reducing the centrifugal force can achieve effective separation and reduce losses due to product breakage caused by excessive centrifugation. Based on this, the central control module sends a speed reduction command (e.g., from 1200 rpm to 900 rpm). This adjustment is feedforward: the centrifugal speed is pre-adjusted according to the growth conditions before the reaction product enters the purification module, avoiding the lag in traditional methods.

[0098] After the product enters the grading and purification module, the online particle size analyzers on each layer of screen 9 monitor the purity data in real time and transmit it to the central control module. The central control module compares the purity value with a preset threshold (e.g., 99.5%): if the purity data is ≥99.5%, the central control module determines it as a qualified product, sends a start command to the screw conveyor of the continuous conveying module, and switches the corresponding three-way valve to send the product into the qualified product hopper. If the purity is <99.5%, the central control module determines it as a substandard product, does not start the screw conveyor, but instead sends a command to the pneumatic conveyor to switch the three-way valve to the circulation return hopper, and sends the substandard product back to the inlet of the grading and purification module for secondary separation via the pneumatic conveyor. For products that still fail to meet the standard after multiple refluxes, the central control module can temporarily store them in the purification hopper to avoid infinite circulation.

[0099] After each batch of production is completed, the central control module will associate and store the following data in the database: temperature distribution characteristics of the entire batch process (time series data of each temperature measurement point); pulse waveform parameter sequence (frequency, duty cycle, amplitude change); centrifuge speed adjustment record; purity data and final yield of the product of each layer of screen 9.

[0100] The central control module uses this data to optimize the empirical correlation model: it compares the actual measured average aspect ratio of the product with the model's predicted value and calculates the prediction error. Regression analysis or machine learning algorithms (such as least squares or neural networks) are used to update the model coefficients, improving prediction accuracy. Simultaneously, a correlation is established between temperature distribution uniformity (such as temperature difference ΔT) and the pulse regulation effect, optimizing the threshold settings for the low-temperature / high-temperature zones, as well as the adjustment range of the hydrogen / carbon source ratio.

[0101] Before the next batch of production begins, the central control module automatically generates initial process parameters based on the optimized model and data from the best historical batches: setting the reference frequency, duty cycle range, and hydrogen / carbon source ratio curve for the pulse waveform; pre-setting the correspondence between centrifugal speed and pulse frequency; and setting the purity threshold and upper limit for the number of refluxes for each sieve 9. During production, the central control module continues to execute the above real-time adjustments and feedforward control. After multiple batch iterations, the system can automatically converge to the optimal process window, thereby improving the batch consistency and overall yield of carbon nanotubes.

[0102] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A carbon nanotube production apparatus, comprising a reaction chamber (1), wherein a main shaft (2) is rotatably fitted inside the reaction chamber (1), characterized in that, The main shaft (2) is provided with a gas distribution mechanism, a reaction mechanism and a purification mechanism from top to bottom. The top of the reaction chamber (1) is also provided with a drive mechanism for rotating the main shaft (2). The gas distribution mechanism is used to distribute the various raw material gases participating in the reaction and modulate the raw material gases into a pulsed gas flow; the reaction mechanism is used to receive the pulsed gas flow and mix the raw material gases to produce a contact reaction to generate reaction products containing carbon nanotubes; the purification mechanism is used to centrifuge the reaction products to separate carbon nanotubes from impurities according to density. The drive mechanism is used to drive the gas distribution mechanism, reaction mechanism and purification mechanism to operate synchronously, so as to realize the continuous production of carbon nanotubes.

2. The carbon nanotube production apparatus according to claim 1, characterized in that, The drive mechanism includes a controller and a drive component (3). The controller and the drive component (3) are connected by signal. The drive component (3) is fixedly connected to the top wall of the reaction chamber (1). The output shaft of the drive component (3) is coaxially fixedly connected to the main shaft (2).

3. The carbon nanotube production apparatus according to claim 2, characterized in that, The gas distribution mechanism includes a gas distribution plate (4) fixedly connected to the upper part of the main shaft (2), and a number of throttling grooves are opened on the gas distribution plate (4); a number of storage cavities (5) for conveying raw materials are fixedly connected to the outer wall of the reaction chamber (1), and the top of each storage cavity (5) is connected to a transmission pipe, and the end of the transmission pipe away from the storage cavity (5) is connected to the top of the reaction chamber (1); a pressure reducing valve for reducing gas pressure and a mass flow meter for controlling gas flow are also provided on the communication path between the transmission pipe and the reaction chamber (1), and the mass flow meter is connected to the controller signal.

4. The carbon nanotube production apparatus according to claim 3, characterized in that, The reaction mechanism includes a spiral fin (6) fixedly connected to the middle of the main shaft (2), and an inner cylinder (7) fixedly connected to the inner wall of the reaction chamber (1). The throttling groove is connected to the inner cylinder (7), and the spiral fin (6) is located inside the inner cylinder (7). A segmented heater (8) is also fitted on the outer wall of the inner cylinder (7), and several temperature sensors are fixedly connected to the inner wall of the inner cylinder (7). The controller is used to acquire the temperature signal emitted by the temperature sensor and control the operation of the segmented heater (8) based on the temperature signal.

5. The carbon nanotube production apparatus according to claim 4, characterized in that, The purification mechanism includes several screens (9) fixedly connected to the lower part of the main shaft (2). Differential bearings (10) are provided at the connection between the screens (9) and the main shaft (2). The aperture of the screens (9) increases from top to bottom. Several sealing rings for filling gaps are also fixedly connected to the inner wall of the reaction chamber (1). The screens (9) are all rotatably engaged with the sealing rings. Several flow ports are opened at the bottom of the inner cylinder (7). Elastic valves (11) are provided at the flow ports. The screens (9) divide the bottom of the reaction chamber (1) into several layers. Each layer is provided with a collection port. The collection ports are all connected to buffer silos (12) for storing different products.

6. A carbon nanotube production system, operating based on the carbon nanotube production apparatus according to any one of claims 1-5, characterized in that, It includes a thermal field control module, a gas supply module, a staged purification module, a continuous delivery module, and a central control module; The thermal field control module is connected to the temperature sensor and the segmented heater (8) to collect temperature data in the reaction chamber (1) in real time and transmit the temperature data to the central control module. The gas supply module is used to provide pulsed airflow to the reaction chamber (1) using the throttling groove of the gas distribution plate (4), and to record the pulse waveform parameters and transmit the pulse waveform parameters to the central control module. The fractionation and purification module is used to centrifuge and fractionate the reaction products, monitor the purity data of the separated products in real time, and transmit the purity data to the central control module. The continuous conveying module is used to switch the conveying path of the reaction products according to the instructions of the central control module; The central control module drives the gas supply module to adjust the pulse waveform parameters based on the received temperature data, predicts the product characteristics based on the pulse waveform parameters and adjusts the rotation speed of the graded purification module, and drives the continuous conveying module to collect qualified products or circulate unqualified products back based on the purity data.

7. The carbon nanotube production system according to claim 6, characterized in that, The temperature measurement points of the thermal field control module are evenly distributed along the axial and circumferential directions of the reaction chamber (1); the segmented heater (8) is independently controlled by the central control module and is used to compensate for heating of local areas according to the temperature data distribution characteristics of the measurement points; The central control module identifies the temperature data distribution characteristics and controls the proportion of hydrogen or carbon source in the pulse airflow of the gas supply module based on the temperature data distribution characteristics; and the pulse waveform parameters match the gas residence time in the reaction chamber (1).

8. The carbon nanotube production system according to claim 7, characterized in that, The central control module has a built-in empirical correlation model between pulse waveform parameters and the aspect ratio of carbon nanotubes. In the empirical correlation model, the pulse waveform parameters are positively correlated with the average aspect ratio. Based on the pulse waveform parameters and duty cycle recorded by the gas supply module, the central control module predicts the average aspect ratio and impurity content of the current batch of reaction products through an empirical correlation model, and sends speed adjustment commands to the staged purification module accordingly.

9. The carbon nanotube production system according to claim 8, characterized in that, The grading and purification module also includes a particle size analyzer set on the screen (9); the continuous conveying module includes a screw conveyor and a pneumatic conveyor, which are respectively connected to the buffer silo (12). The buffer silo (12) includes a qualified product silo, a purified product silo and a circulating return silo. When the particle size analyzer detects that the purity data of the reaction product in one of the sieves (9) reaches the preset threshold, the central control module drives the screw conveyor to transport the reaction product to the qualified product silo. When the purity data does not reach the preset threshold, the pneumatic conveyor is activated to start the circulation backflow, sending the substandard product back to the inlet of the classification and purification module for secondary separation.

10. The carbon nanotube production system according to claim 9, characterized in that, The central control module is also used to associate and store the purity data fed back by the graded purification module with the corresponding pulse waveform parameters and temperature data distribution characteristics, and to optimize the empirical association model. Based on the optimized empirical association model, the pulse waveform adjustment command and centrifugal speed adjustment command for the next production batch are adjusted.

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