Heating furnace for preparing carbon nanotubes and preparation method of carbon nanotubes

Abstract

The invention belongs to the technical field of preparation of carbon nanotubes, and particularly relates to a heating furnace for preparing a carbon nanotube and a preparation method of the carbon nanotube. The heating furnace comprises a furnace tube and a heat insulator arranged on the periphery of the furnace tube; one end of the furnace tube is a feeding end, and the other end is a discharging end; a gap is formed between the heat insulator and the outer wall of the furnace tube and is divided into a plurality of heating cavities arranged in the length direction of the furnace tube, so that a plurality of temperature zones are correspondingly formed in the space in the furnace tube; and a heating element and a temperature detection element are arranged in the heating cavity. On the basis of the heating furnace, the invention also provides a preparation method of the carbon nanotube. According to the heating furnace, the yield and the quality of the carbon nano tubes are improved, meanwhile, the safety and the simplicity of operation are also emphasized, and a relatively comprehensive solution is provided for large-scale continuous industrial production of the carbon nano tubes.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon nanotube preparation, and specifically relates to a heating furnace for preparing carbon nanotubes and a method for preparing carbon nanotubes, in particular to a heating furnace and a method for preparing single-walled carbon nanotubes. Background Art

[0002] Carbon nanotubes, also known as buckytubes, are one-dimensional quantum materials with a special structure. Their radial dimensions are in the nanometer range, their axial dimensions are in the micrometer range, and both ends of the tube are basically sealed. Carbon nanotubes are mainly composed of several to dozens of layers of coaxial circular tubes of carbon atoms arranged in a hexagonal pattern. The distance between layers is fixed, about 0.34 nm, and the diameter is generally 2 to 20 nm.

[0003] According to the number of graphene layers, carbon nanotubes are divided into single-walled carbon nanotubes and multi-walled carbon nanotubes. Among them, single-walled carbon nanotubes have more advantages, which are specifically reflected in: simple structure, stable chemical properties, few structural defects, excellent conductivity, good elasticity and high mechanical properties.

[0004] The production of single-walled carbon nanotubes or carbon nanotubes with some special raw materials as carbon sources is usually based on the transformation of traditional equipment such as fluidized beds, which can effectively increase the output of multi-walled carbon nanotubes, but the output of single-walled carbon nanotubes is still low, with the actual annual production capacity of a single unit only 30-50KG. The development and design of larger-scale mass production equipment for single-walled carbon nanotubes still faces the following challenges.

[0005] The first aspect is the supply of catalyst precursors. The supply of catalyst precursors directly affects the growth quality and yield of carbon nanotubes. The traditional supply method is to place the catalyst precursor in a fixed container, such as a crucible or a porcelain boat, and then place it in a heating furnace. As the temperature rises, the precursor will gradually volatilize and come into contact with the raw gas. There are several problems with this method: first, the volatilization rate of the catalyst precursor in the container is difficult to control, which can easily lead to uneven distribution of catalyst particles in the furnace; second, the catalyst particles are easy to agglomerate at high temperatures, reducing their catalytic activity, thereby affecting the growth efficiency and quality of carbon nanotubes.

[0006] The second aspect is the supply of reaction gas sources. The reaction gas sources mainly include hydrogen, carbon source gas (such as methane or other hydrocarbon gases), etc. In the traditional reactor with a single air intake structure, all reaction gases (including hydrogen, carbon source gas, etc.) enter the reaction chamber through one inlet, and begin to diffuse from the air intake position after entering the reaction chamber. The distribution state after entering the reaction chamber is greatly limited, especially in longer reactors. This air intake method greatly affects the precise control of the gas composition around the catalyst particles, and thus affects the utilization rate of the air intake and the growth quality of carbon nanotubes.

[0007] The third aspect is the collection of the prepared carbon nanotube flocs. High-quality carbon nanotubes will form very fluffy flocs. If they are not removed in time, it will cause the furnace tube to be blocked, increase the internal pressure, and affect the continuous production and the safety of the equipment. The existing carbon nanotube production equipment adopts an intermittent collection method, and discharges materials on time according to the output, which seriously affects the continuity and output of production, and it is easy to cause the carbon nanotube flocs to accumulate and block the furnace tube. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention provides a heating furnace for preparing carbon nanotubes and a method for preparing carbon nanotubes.

[0009] The present invention provides a first aspect of a heating furnace for preparing carbon nanotubes, comprising a furnace tube and an insulator arranged on the outer periphery of the furnace tube; one end of the furnace tube is a feeding end, and the other end is a discharging end; there is a gap between the insulator and the outer wall of the furnace tube, and the gap is divided into a plurality of heating chambers arranged along the length direction of the furnace tube, so that the space in the furnace tube forms a plurality of temperature zones correspondingly; a heating element and a temperature detection element are arranged in the heating chamber.

[0010] Furthermore, a plurality of air inlet pipes are led out from the side wall of the furnace tube and along the length direction of the furnace tube, and each air inlet pipe is connected to the interior of the furnace tube to supply raw gas to different parts of the furnace tube.

[0011] Furthermore, the heating element is an electric heating tube, and each heating chamber is provided with an independently controllable heating element to form a plurality of independently adjustable temperature zones along the length direction of the furnace tube.

[0012] Furthermore, in each heating chamber, the heating elements are arranged along the length direction of the furnace tube to form two rows of symmetrical heating element arrays; in each heating chamber, a temperature detection element is provided, the temperature detection element is a thermocouple, and the detection end of the thermocouple protrudes from the inner wall of the insulation body and points into the heating chamber.

[0013] Furthermore, each air inlet duct has a preheating section on the outer wall of the furnace tube, and the preheating section passes through the heating chamber.

[0014] Furthermore, the furnace tube is connected to an air inlet pipe corresponding to each temperature zone, and each air inlet pipe has an independent air inlet end to independently control the raw gas supply of each temperature zone.

[0015] Furthermore, the heating furnace also includes a cooling hood arranged outside the heat insulating body, the cooling hood includes an inner hood body that encloses the heat insulating body and an outer hood body that encloses the inner hood body; a cooling cavity for accommodating a cooling medium is formed between the inner hood body and the outer hood body, and a first liquid inlet and a first liquid outlet are also provided on the outer hood body; the first liquid inlet and the first liquid outlet are both connected to the cooling cavity.

[0016] Furthermore, the first liquid inlet is located at the lower part of the cooling cavity, and the first liquid outlet is located at the upper part of the cooling cavity.

[0017] Furthermore, at the feed end, the outer wall of the furnace tube is also wrapped with a cooling jacket, which can accommodate cooling medium, a second liquid inlet is provided at the lower part of the cooling jacket, and a second liquid outlet is provided at the upper part of the cooling jacket.

[0018] Furthermore, a protective shell is provided outside the cooling cover.

[0019] Furthermore, the protective shell blocks the peripheral side of the furnace tube and leaves an operation window at the feed end of the furnace tube.

[0020] A conduit extending into the furnace tube is arranged at the feed end of the furnace tube, and an atomizing nozzle is connected to one end of the conduit located in the furnace tube.

[0021] Furthermore, the atomizing nozzle is located within a temperature zone close to the feed end.

[0022] Furthermore, the feed end of the furnace tube has a flange opening, and the conduit is provided with a sealing connection plate, and the flange opening of the feed end of the furnace tube is detachably connected to the sealing connection plate on the conduit.

[0023] Furthermore, a carbon nanotube discharging device is provided at the discharging end of the heating furnace, and the discharging end includes a collecting bin, and the collecting bin has a collecting cavity connected to the discharging port of the tubular heating furnace; an operating port is provided in the collecting bin, and a flexible pipe is connected to the operating port, and the operating port is sealedly connected to the proximal end of the flexible pipe; at least one operating rod passes through the flexible pipe and extends into the collecting cavity, and the distal end of the flexible pipe is sealedly connected to the operating rod; a discharging interface is provided at the bottom of the collecting bin.

[0024] Furthermore, the flexible pipe is an elastic bellows made of metal material.

[0025] Furthermore, the end of the operation port has a flange port, the proximal end of the flexible pipe has a flange port, and the flange port at the end of the operation port and the flange port at the proximal end of the flexible pipe are detachably connected.

[0026] Furthermore, the distal end of the operating port has a flange opening, the rod body of the joystick is provided with a sealing connecting plate, and the flange opening at the distal end of the operating port is detachably connected to the sealing connecting plate on the joystick.

[0027] Furthermore, a hook is provided at one end of the operating rod located in the collecting bin, and a handle is provided at one end of the operating rod located outside the collecting bin.

[0028] Furthermore, the bottom of the collecting bin is conical and is provided with a discharge port at the bottom; a sealed bin door is provided on the side of the collecting bin directly opposite to the discharge port of the tubular heating furnace, and the operation port is provided on the sealed bin door.

[0029] Furthermore, at least one observation window is provided on the collection bin, and the observation window and the operation port are located on the same side of the collection bin.

[0030] Furthermore, a winding roller is rotatably provided in the collecting bin, and the winding roller is driven to rotate by a driving motor installed on the outer side wall of the collecting bin.

[0031] Furthermore, the collecting bin has an interlayer space in its wall, and a circulating cooling medium can be maintained in the interlayer space.

[0032] Furthermore, the distal end and proximal end of the flexible pipe are of the same size; or the proximal end of the flexible pipe is larger than the distal end, forming a bell-mouth shape.

[0033] The second aspect of the present invention is to provide a method for preparing carbon nanotubes, which is prepared by using the above-mentioned heating furnace.

[0034] Beneficial Effects Compared with the prior art, the tubular heating furnace for preparing carbon nanotubes provided by the present invention has the following beneficial effects: The design between the heating chamber and the furnace tube enables each heating chamber to independently control the temperature, forming different temperature zones throughout the reaction process, which helps to accurately control the growth temperature of carbon nanotubes at different stages and improve yield and quality.

[0035] The raw gas supply adopts a multi-point air inlet pipeline, so that the raw gas (such as hydrogen, carbon source) can be supplied in different temperature zones according to the needs of different growth stages. This can not only improve the utilization rate of the carbon source, but also shorten the agglomeration time of the catalyst particles, thereby increasing the yield of single-walled carbon nanotubes.

[0036] An efficient cooling system helps to remove excess heat generated by the heating furnace during operation, protects external equipment and the environment from high temperatures, helps control the overall temperature distribution of the heating furnace, and ensures the safety of operators.

[0037] The catalyst precursor is introduced into the furnace using an atomizing nozzle, which increases the contact area between the catalyst and the raw gas, improves the utilization efficiency of the catalyst, and enables the carbon nanotubes to grow more evenly.

[0038] The collection bin at the discharge end helps to remove the flocculent single-walled carbon nanotubes formed during the growth process in time, prevents the furnace tube from being blocked, ensures the continuity of production, and improves safety. The collection bin is equipped with a flexible pipe and a joystick so that the operator can collect the carbon nanotubes without affecting the normal operation of the heating furnace. The collection bin is equipped with a rotatable winding roller, which helps to collect the carbon nanotube flocs in an orderly manner, avoids material accumulation and confusion, and improves the collection efficiency.

[0039] In summary, the heating furnace of the present invention improves the yield and quality of carbon nanotubes while also focusing on the safety and simplicity of operation, thus providing a more comprehensive solution for the large-scale continuous industrial production of carbon nanotubes. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 and Figure 2 It is a schematic diagram of the overall structure of the heating furnace.

[0041] Figures 3 to 6 Schematic diagram of the internal structure of the heating furnace.

[0042] Figure 7 Schematic diagram of the internal structure of the furnace tube.

[0043] Figure 8 It is a schematic diagram of the transverse section of the interior of the heating furnace.

[0044] Fig. 9 It is a schematic diagram of the structure of the feed end of the furnace tube.

[0045] Fig.10 This is a schematic diagram of the structure of the collection bin.

[0046] Fig.11 This is a schematic diagram of the structure inside the collection bin.

[0047] Fig.12 A schematic diagram of the structure of the joystick assembly.

[0048] Fig.13 It is a schematic diagram of the structure of the winding roller assembly.

[0049] In the figure: 1. furnace tube; 2. insulation; 3. cooling cover; 4. cooling jacket; 5. protective shell; 6. collecting bin; 11. air inlet pipe; 15. conduit; 16. atomizing nozzle; 21. heating chamber; 22. electric heating tube; 31. inner cover; 32. outer cover; 33. cooling chamber; 34. first liquid inlet; 35. first liquid outlet; 41. second liquid inlet; 42. second liquid outlet; 61. operating port; 62. flexible pipe; 63. joystick; 64. sealed bin door; 65. observation window; 66. winding roller; 67. driving motor; 111. preheating section. DETAILED DESCRIPTION

[0050] The present invention is further illustrated by the following examples, which are intended to more clearly illustrate the technical solution of the present invention and should not be construed as a limitation.

[0051] The preparation of carbon nanotubes requires that the raw materials including hydrogen, catalyst precursor, growth promoter precursor and carbon source are subjected to high-temperature reaction in a heating furnace. The catalyst precursor decomposes and collision-reduced into catalyst particles. The carbon source decomposes on the surface of the catalyst and dissolves into the catalyst. The carbon cap is then precipitated through diffusion. The continuous supply of carbon source causes the carbon cap to elongate to form carbon nanotubes, which flow to the tail end of the reaction chamber with the hydrogen flow, eventually forming single-walled carbon nanotubes that grow in different macroscopic forms such as thin films or sponges.

[0052] like Figures 1 to 6 A tubular heating furnace for preparing carbon nanotubes is shown, comprising at least one furnace tube 1 and a heat insulator 2 arranged on the outer periphery of the furnace tube 1; the furnace tube 1 is a high temperature resistant pipe, which can be one or multiple furnace tubes arranged in parallel, and the figure shows two furnace tubes 1 arranged in parallel on the heat insulator 2 as an example. The heat insulator 2 is made of a heat-insulating material with a low thermal conductivity coefficient and can be integrally formed or spliced. One end of the furnace tube 1 is a feed end, and the other end is a discharge end; there is a gap between the heat insulator 2 and the outer wall of the furnace tube 1, and the gap is divided into a plurality of heating chambers 21 arranged along the length direction of the furnace tube 1, so that the space in the furnace tube 1 forms a plurality of temperature zones; a heating element and a temperature detection element are arranged in the heating chamber 21. Among them, the furnace tube 1 is used to accommodate reactants and provide heating and reaction space, and the plurality of heating chambers 21 arranged between the heat insulator 2 and the furnace tube 1 can control different heating temperatures, the heating element heats the heating chamber 21, and the temperature detection element detects the temperature of the heating chamber 21 to provide a basis for temperature control.

[0053] In some embodiments, the catalyst precursor can be placed in a high temperature resistant container such as a crucible or a porcelain boat, and then the high temperature resistant container is placed in the furnace tube 1. In other embodiments, the catalyst precursor can also be gradually introduced into the furnace tube 1 through a pipeline at the feed end along with the air flow.

[0054] In some embodiments, the carbon source gas can be introduced into the furnace tube 1 through a pipeline at the feed end. In other embodiments, the carbon source gas can also be introduced into the furnace tube 1 from a single point or multiple points on the side wall of the furnace tube 1.

[0055] Preferably, if Figure 6 and Figure 7 As shown, multiple air inlet pipes 11 are led out on the side wall of the furnace tube 1 and along the length direction of the furnace tube 1, and each air inlet pipe 11 is connected to the inside of the furnace tube 1 to supply raw gas to different parts in the furnace tube 1. Experiments have found that in the process of growing single-walled carbon nanotubes by the floating catalyst method, the requirements for hydrogen and carbon sources are different at different stages. The structure of multi-point air inlet along the side wall of the furnace tube 1 can just introduce the adapted raw gas at different temperature zones for different stages, which can significantly improve the utilization rate of the carbon source, and the time for the catalyst particles to agglomerate and grow before starting to grow is also shorter, thereby increasing the yield of single-walled carbon nanotubes.

[0056] Preferably, if Figure 5 and Figure 6 As shown, the heating element is an electric heating tube 22, and each heating chamber 21 is provided with an independently controllable heating element. As a heating element, each or each group of electric heating tubes 22 can be independently controlled in their respective heating chambers 21, which enables the operator to accurately set different temperature zones along the length direction of the furnace tube 1, thereby optimizing the temperature conditions during the growth of carbon nanotubes and improving the quality and yield of the product.

[0057] Preferably, if Figure 5 and Figure 6 As shown, in each heating chamber 21, the heating elements are arranged along the length direction of the furnace tube 1 to form two rows of symmetrical heating element arrays; in each heating chamber 21, a temperature detection element is provided, and the temperature detection element is a thermocouple, and the detection end of the thermocouple protrudes from the inner wall of the insulation body 2 and points to the heating chamber 21, ensuring the accuracy and real-time performance of the temperature measurement, thereby providing precise temperature feedback for temperature control.

[0058] like Figure 7 As shown, each air inlet pipe 11 has a preheating section 111 adjacent to the outer wall of the furnace tube 1. The preheating section 111 passes through the heating chamber 21, so that the gas transported through the pipe can be preheated before entering the furnace tube 1, thereby reducing the temperature fluctuation inside the furnace tube 1, which is beneficial to improving the reaction efficiency.

[0059] like Figure 6 As shown, the furnace tube 1 is connected to an air inlet pipe 11 corresponding to each temperature zone, and each air inlet pipe 11 has an independent air inlet end to independently control the supply of raw gas to each temperature zone. In this way, the supply of raw gas can be accurately controlled according to the different requirements of carbon nanotube growth in different temperature zones. This design improves the utilization efficiency of carbon source and the growth quality of carbon nanotubes.

[0060] Preferably, if Figure 3 , Figure 4 and Figure 8As shown, the tubular heating furnace also includes a cooling cover 3 arranged outside the insulation body 2, and the cooling cover 3 includes an inner cover body 31 enveloping the insulation body 2 and an outer cover body 32 enveloping the inner cover body 31; a cooling cavity 33 for accommodating a cooling medium is formed between the inner cover body 31 and the outer cover body 32, and a first liquid inlet 34 and a first liquid outlet 35 are also provided on the outer cover body 32; the first liquid inlet 34 and the first liquid outlet 35 are both connected to the cooling cavity 33. A cooling system consisting of an inner and outer double layer is added outside the insulation body 2, and the cooling cavity 33 can accommodate a cooling medium, and the coolant is injected through the first liquid inlet 34, and is discharged from the first liquid outlet 35 after passing through the cooling cavity 33, effectively taking away the excess heat generated when the heating furnace is working, protecting the external equipment and the environment from the influence of high temperature, and also helping to control the overall temperature distribution of the heating furnace.

[0061] Preferably, if Figure 4 As shown, the first liquid inlet 34 is located at the lower part of the cooling cavity 33, and the first liquid outlet 35 is located at the upper part of the cooling cavity 33, which helps cooling media such as water and thermal oil to fully cool the cavity 33, promotes the circulation of the cooling medium, and improves the cooling efficiency.

[0062] Preferably, if Figure 6 , Figure 7 and Fig. 9 As shown, at the feed end, the outer wall of the furnace tube 1 is also wrapped with a cooling jacket 4, which can accommodate cooling medium, and a second liquid inlet 41 is provided at the lower part of the cooling jacket 4, and a second liquid outlet 42 is provided at the upper part of the cooling jacket 4. The cooling medium enters from the second liquid inlet 41 at the lower part of the cooling jacket 4, absorbs the heat emitted by the furnace tube 1, and then flows out from the second liquid outlet 42 at the upper part, which helps to reduce the temperature of the feed end and protect the safety of the operator.

[0063] Preferably, if Figure 1 and Figure 2 As shown, a protective shell 5 is further provided on the outside of the cooling cover 3. The protective shell 5 blocks the peripheral side of the furnace tube 1 and leaves an operation window at the feed end of the furnace tube 1.

[0064] As mentioned above, the catalyst precursor can be placed in a high temperature resistant container such as a crucible or a porcelain boat, and then the high temperature resistant container is placed in the furnace tube 1. As the temperature rises, the catalyst precursor gradually evaporates into the atmosphere in the furnace tube 1, reacts with the raw gas, and the catalytic carbon source grows into carbon nanotubes in a specific arrangement. However, due to the limitations of contact and dispersion in this method, not only is the utilization efficiency of the catalyst low, but the catalytic activity is also not fully exerted. For this reason, it can be as follows Figure 7As shown, a conduit 15 extending into the furnace tube 1 is provided at the feed end of the furnace tube 1, and an atomizing nozzle 16 is connected to one end of the conduit 15 in the furnace tube 1. The catalyst precursor can be evenly dispersed into the reaction atmosphere in the furnace tube 1 through the atomizing nozzle, increasing the contact between the catalyst and the raw gas, thereby promoting a more effective catalytic reaction and promoting efficient and uniform growth of carbon nanotubes. On the other hand, the catalyst precursor is preheated during the flow process in the furnace tube 1, reducing agglomeration, providing more active sites, and achieving efficient and high-purity single-walled carbon nanotube growth.

[0065] Preferably, the atomizing nozzle 16 is located in a temperature zone close to the feed end.

[0066] Preferably, if Fig. 9 As shown, the feed end of the furnace tube 1 has a flange, and the conduit 15 is provided with a sealing connecting plate. The flange at the feed end of the furnace tube 1 and the sealing connecting plate on the conduit 15 are detachably connected, for example, by bolts, clamps and other connecting parts to achieve detachable connection.

[0067] The single-walled carbon nanotubes grown by the floating catalyst chemical vapor deposition method are flocculent, light in weight, and bulky in size. They are easily adhered to the low-temperature area of ​​the reaction chamber, causing the furnace tube 1 to be blocked and the pressure in the furnace to increase, thus affecting the continuity and safety of production.

[0068] like Figure 1 , Fig.10 , Fig.11 and Fig.12 As shown, a carbon nanotube discharging device is provided at the discharging end of the tubular heating furnace. The discharging device comprises a collecting bin 6, wherein the collecting bin 6 has a collecting cavity connected to the discharging port of the tubular heating furnace, that is, the furnace tube 1 is connected to the collecting bin 6; an operating port 61 is provided on the collecting bin 6, and a flexible pipe 62 is connected to the operating port 61, and the operating port 61 is sealedly connected to the proximal end of the flexible pipe 62; at least one operating rod 63 passes through the flexible pipe 62 and extends into the collecting cavity, and the distal end of the flexible pipe 62 is sealedly connected to the operating rod 63; and a discharging interface is provided at the bottom of the collecting bin 6.

[0069] This discharging device is provided with a collecting bin 6 at the discharging port of the furnace tube 1, and the operating port 61 is connected to at least one joystick 63 extending into the collecting bin through a flexible pipe 62, allowing the operator to safely transfer and collect the flocculent single-walled carbon nanotubes that are easy to cause clogging of the furnace tube during the growth process from the outside. In addition, a transfer tank can be connected to the discharging interface. When the flocculent single-walled carbon nanotubes in the collecting bin 6 accumulate to a certain amount, the operator can use the joystick 63 to transfer the flocculent to the transfer tank, and then cut off the connection between the discharging interface and the transfer tank, and replace the new transfer tank. In this way, the operation of the heating furnace is not affected during the operation, and the discharging is achieved without affecting the continuous production, thereby solving the problems of continuous production and safety, and improving the mass production capacity of single-walled carbon nanotubes.

[0070] Preferably, the flexible pipe 62 is an elastic bellows made of metal. The elastic bellows made of metal not only has good high temperature resistance and can withstand the high temperature environment of the heating furnace, but also has good flexibility and elasticity, which can adapt to the position adjustment or slight movement of the collection bin 6, and at the same time allow the joystick 63 to have a large linear and rotational activity space during operation. Metal bellows usually also have high mechanical strength and durability, can effectively prevent deformation or rupture caused by external pressure changes, and ensure the safety and stability of operation.

[0071] like Fig.12 As shown, the distal end and proximal end of the flexible pipe 62 may be the same size, forming a pipe with a substantially uniform diameter. Preferably, the proximal end of the flexible pipe 62 may be larger than the distal end, forming a bell-shaped shape, so that the joystick 63 has a larger operating space and improves the flexibility of the joystick 63.

[0072] Preferably, if Fig.12 As shown, the end of the operating port 61 has a flange opening, and the proximal end of the flexible pipe 62 has a flange opening. The flange opening at the end of the operating port 61 and the flange opening at the proximal end of the flexible pipe 62 are detachably connected. For example, the detachable connection is achieved by connecting parts such as bolts and clamps, which not only ensures the sealing, but also allows the operating lever 63 to be easily replaced or removed as needed, thereby enhancing the operational flexibility of the equipment.

[0073] Preferably, if Fig.12 As shown, the distal end of the operating port 61 has a flange opening, and the rod body of the operating rod 63 is provided with a sealing connecting plate. The flange opening at the distal end of the operating port 61 and the sealing connecting plate on the operating rod 63 are detachably connected. Similarly, a detachable connection can also be achieved through connecting parts such as bolts and clamps, which is convenient for quick assembly and disassembly, and easy for maintenance and cleaning.

[0074] Preferably, if Fig.12As shown, a hook is provided at one end of the joystick 63 located inside the collecting bin 6, and a handle is provided at one end of the joystick 63 located outside the collecting bin 6. The hook at the front end of the joystick 63 can be used to hook or move the carbon nanotube flocs inside the collecting bin 6, while the handle facilitates the operator to apply force outside the collecting bin 6 to control the movement of the joystick 63, thereby improving the convenience and safety of operation.

[0075] Preferably, if Fig.11 As shown, the bottom of the collecting bin 6 is conical and is provided with a discharge port at the bottom; a sealed bin door 64 is provided on the side of the collecting bin 6 that is opposite to the discharge port of the tubular heating furnace, and the operation port 61 is provided on the sealed bin door 64.

[0076] Preferably, if Fig.11 As shown, at least one observation window 65 is further provided on the collecting bin 6 , and the observation window 65 and the operation port 61 are located on the same side of the collecting bin 6 .

[0077] Preferably, if Fig.11 and Fig.13 As shown, a winding roller 66 is rotatably provided in the collecting bin 6, and the winding roller 66 is driven to rotate by a driving motor 67 installed on the outer wall of the collecting bin 6, so that the prepared carbon nanotube flocs can be orderly wound on the roller, avoiding the accumulation and confusion of the materials. After winding, it is also convenient for the joystick 63 to push the carbon nanotube flocs off as a whole, which is convenient for full collection, thereby improving the collection efficiency and neatness.

[0078] Preferably, if Fig.11 As shown, there is an interlayer space in the wall of the collecting bin 6, and a circulating cooling medium can be maintained in the interlayer space to prevent the outer wall temperature of the collecting bin 6 from being too high.

[0079] The above embodiments are exemplary, and their purpose is to illustrate the technical concept and features of the present invention so that people familiar with the technology in this field can understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A heating furnace for preparing carbon nanotubes, characterized in that: The invention comprises a furnace tube (1) and a heat insulator (2) arranged on the outer periphery of the furnace tube (1); one end of the furnace tube (1) is a feed end, and the other end is a discharge end; there is a gap between the heat insulator (2) and the outer wall of the furnace tube (1), and the gap is divided into a plurality of heating chambers (21) arranged along the length direction of the furnace tube (1), so that the space inside the furnace tube (1) forms a plurality of temperature zones; a heating element and a temperature detection element are arranged in the heating chamber (21); a guide tube (15) extending into the furnace tube (1) is arranged at the feed end of the furnace tube (1), and an atomizing nozzle (16) is connected to one end of the guide tube (15) located in the furnace tube (1).

2. The heating furnace for preparing carbon nanotubes according to claim 1, characterized in that: The atomizing nozzle (16) is located in a temperature zone close to the feed end.

3. The heating furnace for preparing carbon nanotubes according to claim 1, characterized in that: The feed end of the furnace tube (1) has a flange opening, the guide tube (15) is provided with a sealing connection plate, and the flange opening of the feed end of the furnace tube (1) and the sealing connection plate on the guide tube (15) are detachably connected.

4. The heating furnace for preparing carbon nanotubes according to claim 1, characterized in that: A plurality of air inlet pipes (11) are extended from the side wall of the furnace tube (1) and along the length direction of the furnace tube (1), and each of the air inlet pipes (11) is connected to the interior of the furnace tube (1) so as to supply raw gas to different parts of the furnace tube (1).

5. The heating furnace for preparing carbon nanotubes according to claim 4, characterized in that: Each of the air inlet pipes (11) has a preheating section (111) on the outer wall of the furnace tube (1), and the preheating section (111) passes through the heating chamber (21).

6. The heating furnace for preparing carbon nanotubes according to claim 5, characterized in that: The furnace tube (1) is connected to an air inlet pipe (11) corresponding to each temperature zone, and each air inlet pipe (11) has an independent air inlet end to independently control the supply of raw gas to each temperature zone.

7. The heating furnace for preparing carbon nanotubes according to any one of claims 1 to 6, characterized in that: A carbon nanotube discharge device is provided at the discharge end of the tubular heating furnace, the discharge device comprising a collecting bin (6), the collecting bin (6) having a collecting cavity in communication with the discharge port of the tubular heating furnace; an operating port (61) is provided in the collecting bin (6), a flexible pipe (62) is connected to the operating port (61), the operating port (61) is sealedly connected to the proximal end of the flexible pipe (62); at least one operating rod (63) passes through the flexible pipe (62) and extends into the collecting cavity, the distal end of the flexible pipe (62) is sealedly connected to the operating rod (63); and a discharge interface is provided at the bottom of the collecting bin (6).

8. The heating furnace for preparing carbon nanotubes according to claim 7, characterized in that: The flexible pipe (62) is an elastic bellows made of metal; the end of the operating port (61) has a flange, the proximal end of the flexible pipe (62) has a flange, and the flange at the end of the operating port (61) is detachably connected to the flange at the proximal end of the flexible pipe (62); the distal end of the operating port (61) has a flange, a sealing connection plate is provided on the rod body of the operating rod (63), and the flange at the distal end of the operating port (61) is detachably connected to the sealing connection plate on the operating rod (63); a hook is provided at one end of the operating rod (63) located inside the collecting bin (6), and a handle is provided at one end of the operating rod (63) located outside the collecting bin (6); the distal end of the flexible pipe (62) is the same size as the proximal end; or the proximal end of the flexible pipe (62) is larger than the distal end, forming a bell-mouth shape.

9. The heating furnace for preparing carbon nanotubes according to claim 7, characterized in that: A winding roller (66) is also rotatably provided in the collection bin (6), and the winding roller (66) is driven to rotate by a driving motor (67) mounted on the outer side wall of the collection bin (6).

10. A method for preparing carbon nanotubes, characterized in that: The preparation is carried out using the heating furnace described in any one of claims 1 to 9.

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