A heating furnace for preparing carbon nanotubes and a method for preparing carbon nanotubes

Abstract

The present application belongs to the technical field of carbon nanotube preparation, and particularly relates to a heating furnace for preparing carbon nanotubes and a method for preparing carbon nanotubes. The heating furnace comprises a furnace tube and a heat insulating body 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. The heat insulating body has a space with the outer wall of the furnace tube, and the space is divided into a plurality of heating cavities arranged along the length direction of the furnace tube, so that the space in the furnace tube corresponds to form a plurality of temperature zones. The heating cavities are provided with heating elements and temperature detecting elements. A method for preparing carbon nanotubes is further provided based on the heating furnace. The heating furnace improves the yield and quality of carbon nanotubes, and also pays attention to the safety and simplicity of operation, thereby providing a relatively comprehensive solution for the mass and continuous industrial production of carbon nanotubes.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of carbon nanotube preparation, and particularly relates to a heating furnace for preparing carbon nanotubes and a carbon nanotube preparation method, especially a heating furnace and a preparation method for preparing single-walled carbon nanotubes BACKGROUND

[0002] Carbon nanotubes, also known as Buckminsterfullerene tubes, are one-dimensional quantum materials with special structures, with a radial size of nanometer level and an axial size of micrometer level, and both ends of the tube are basically sealed. Carbon nanotubes are mainly composed of carbon atoms arranged in a hexagonal shape, forming a coaxial circular tube with several to several tens of layers. The distance between the layers is fixed at about 0.34 nm, and the diameter is generally 2-20 nm.

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

[0004] Single-walled carbon nanotube production or carbon nanotube production using some special raw materials as carbon sources is usually based on the modification of traditional equipment such as fluidized bed, which can effectively improve the yield of multi-walled carbon nanotubes, but the yield of single-walled carbon nanotubes is still low, and the actual annual production capacity of a single machine is only 30-50 kg. In the development and design of larger-scale single-walled carbon nanotube production equipment, there are still many 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 precursors 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 precursors will gradually volatilize and come into contact with the raw material gas. This method has several problems: first, the volatilization speed of the catalyst precursors in the container is difficult to control, which can easily lead to uneven distribution of catalyst particles in the furnace; second, catalyst particles can easily agglomerate at high temperatures, reducing their catalytic activity and 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 single gas inlet structure of the reaction furnace, all reaction gases (including hydrogen, carbon source gas, etc.) enter the reaction chamber through one inlet, and after entering the reaction chamber, they diffuse from the gas inlet position. The distribution state after entering the reaction chamber is greatly limited, especially in a long reaction furnace. This gas inlet method greatly affects the accurate control of the gas composition around the catalyst particles, and further affects the utilization rate of the gas inlet and the growth quality of the carbon nanotubes.

[0007] The third aspect is the collection of the prepared carbon nanotube floc. The high-quality carbon nanotube growth forms very fluffy floc, which, if not removed in time, will cause the furnace tube to be blocked, increase the internal pressure, and affect the continuity of production and the safety of the equipment. The existing carbon nanotube production device adopts an intermittent collection mode, discharges according to the production at a certain time, seriously affects the continuity of production and the yield, and is easy to cause the accumulation of carbon nanotube floc products and block the furnace tube. SUMMARY

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

[0009] The present application provides a first aspect to provide a heating furnace for preparing carbon nanotubes, comprising a furnace tube and a heat insulation body 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; the heat insulation body and the outer wall of the furnace tube have a gap, the gap is divided into a plurality of heating cavities arranged along the length direction of the furnace tube, so that the space in the furnace tube corresponds to form a plurality of temperature zones; a heating element and a temperature detection element are arranged in the heating cavity.

[0010] Further, a plurality of gas inlet pipes are led out on the side wall of the furnace tube and along the length direction of the furnace tube, each gas inlet pipe communicates with the inside of the furnace tube to supply raw material gas to different parts in the furnace tube.

[0011] Further, the heating element is an electric heating pipe, and each heating cavity is provided with an independently controllable heating element, so as to form a plurality of temperature zones with independently adjustable temperatures along the length direction of the furnace tube.

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

[0013] Further, each gas inlet pipe has a preheating section of the outer wall of the furnace tube, and the preheating section passes through the heating cavity.

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

[0015] Further, the heating furnace further comprises a cooling cover arranged outside the heat insulation body, the cooling cover comprises an inner cover body enveloping the heat insulation body and an outer cover body enveloping the inner cover body; a cooling cavity containing a cooling medium is formed between the inner cover body and the outer cover body, and a first liquid inlet and a first liquid outlet are further arranged on the outer cover body; the first liquid inlet and the first liquid outlet communicate with the cooling cavity.

[0016] Further, 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] Further, at the feeding end, the outer wall of the furnace tube is further wrapped with a cooling jacket, the cooling jacket can accommodate a cooling medium, the lower part of the cooling jacket is provided with a second liquid inlet, and the upper part of the cooling jacket is provided with a second liquid outlet.

[0018] Further, the outer part of the cooling cover is further provided with a protective shell.

[0019] Further, the protective shell blocks the circumferential side of the furnace tube and leaves an operation window at the feeding end of the furnace tube.

[0020] A guide pipe extending into the furnace tube is arranged at the feeding end of the furnace tube, and an atomizing nozzle is connected to the end of the guide pipe in the furnace tube.

[0021] Further, the atomizing nozzle is located within a temperature range close to the feeding end.

[0022] Further, the feeding end of the furnace tube has a flange, the guide pipe is provided with a sealing connecting plate, and the flange of the feeding end of the furnace tube is detachably connected to the sealing connecting plate of the guide pipe.

[0023] Further, a carbon nanotube discharging device is arranged at the discharging end of the heating furnace, the discharging end comprises a collecting bin, the collecting bin has a collecting cavity in communication with the discharging port of the tubular heating furnace; an operation port is arranged on the collecting bin, a flexible pipe is connected to the operation port, the operation port is sealingly connected to the proximal end of the flexible pipe; at least one operating rod extends into the collecting cavity through the flexible pipe, the distal end of the flexible pipe is sealingly connected to the operating rod; and a discharging interface is arranged at the bottom of the collecting bin.

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

[0025] Further, the end of the operation port has a flange, the proximal end of the flexible pipe has a flange, and the flange of the end of the operation port is detachably connected to the flange of the proximal end of the flexible pipe.

[0026] Further, the distal end of the operation port has a flange, and the rod body of the operating rod is provided with a sealing connecting plate, and the flange of the distal end of the operation port is detachably connected to the sealing connecting plate of the operating rod.

[0027] Further, the end of the operating rod located in the collecting bin has a hook, and the end of the operating rod located outside the collecting bin has a handle.

[0028] Further, the bottom of the collecting bin is conical and is provided with a discharging port at the bottom; a sealing bin door is arranged on the side of the collecting bin opposite to the discharging port of the tubular heating furnace, and the operation port is arranged on the sealing bin door.

[0029] Further, at least one observation window is arranged on the collecting bin, and the observation window and the operation port are located on the same side of the collecting bin.

[0030] Further, a winding roller is rotatably arranged in the collecting bin, and the winding roller is driven to rotate by a driving motor mounted on the outer sidewall of the collecting bin.

[0031] Further, the bin wall of the collecting bin has a sandwich space, and a circulating cooling medium can be kept in the sandwich space.

[0032] Further, the distal end and the proximal end of the flexible pipe have the same size, or the proximal end of the flexible pipe is larger than the distal end, forming a horn mouth shape.

[0033] The second aspect of the present application provides a method for preparing carbon nanotubes by using the above-mentioned heating furnace.

[0034] Advantages

[0035] Compared with the prior art, the tubular heating furnace for preparing carbon nanotubes provided by the present application has the following advantages:

[0036] The design between the heating cavity and the furnace tube enables each heating cavity to be independently controlled in temperature, forming different temperature zones during the entire reaction process, which helps to accurately control the growth temperature of carbon nanotubes at different stages and improve the yield and quality.

[0037] The multi-point gas inlet pipeline for supplying raw material gas enables the raw material gas (such as hydrogen and carbon source) to be supplied in different temperature zones according to the needs of different growth stages, which not only improves the utilization rate of the carbon source, but also shortens the agglomeration time of the catalyst particles, thereby improving the yield of single-walled carbon nanotubes.

[0038] The high-efficiency cooling system helps to remove excess heat generated during the operation of the heating furnace, protects external equipment and the environment from high temperatures, helps to control the overall temperature distribution of the heating furnace, and ensures the safety of the operator.

[0039] The use of the atomizing nozzle to introduce the catalyst precursor into the furnace increases the contact area between the catalyst and the raw material gas, improves the utilization efficiency of the catalyst, and enables the carbon nanotubes to grow more uniformly.

[0040] The collecting bin arranged at the discharge end helps to timely remove the flocculent single-walled carbon nanotubes formed during the growth process, prevents the furnace tube from being blocked, ensures the continuity of production, and improves safety. The flexible pipe and the operating rod arranged on the collecting bin enable the operator to perform the carbon nanotube collection work without affecting the normal operation of the heating furnace. The rotatable winding roller arranged inside the collecting bin helps to orderly collect the flocculent carbon nanotube material, avoids material accumulation and chaos, and improves the collection efficiency.

[0041] In summary, the heating furnace of the present application improves the yield and quality of carbon nanotubes, and pays attention to the safety and simplicity of operation, thereby providing a more comprehensive solution for the mass continuous industrial production of carbon nanotubes. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 and Figure 2 It is a schematic diagram of the overall structure of the heating furnace.

[0043] Figures 3 to 6 It is a schematic diagram of the internal structure of the heating furnace.

[0044] Figure 7 It is a schematic diagram of the internal structure of the furnace tube.

[0045] Figure 8 It is a schematic diagram of the transverse section of the internal structure of the heating furnace.

[0046] Figure 9 It is a schematic diagram of the structure of the feeding end of the furnace tube.

[0047] Figure 10 It is a schematic diagram of the structure of the collection bin.

[0048] Figure 11 It is a schematic diagram of the internal structure of the collection bin.

[0049] Figure 12 It is a schematic diagram of the structure of the operating rod assembly.

[0050] Figure 13 It is a schematic diagram of the structure of the winding roller assembly.

[0051] In the figure: 1, furnace tube; 2, heat insulating body; 3, cooling cover; 4, cooling jacket; 5, protective shell; 6, collection bin; 11, air inlet pipe; 15, guide pipe; 16, atomizing nozzle; 21, heating cavity; 22, electric heating tube; 31, inner cover body; 32, outer cover body; 33, cooling cavity; 34, first liquid inlet; 35, first liquid outlet; 41, second liquid inlet; 42, second liquid outlet; 61, operating port; 62, flexible pipe; 63, operating rod; 64, sealing bin door; 65, observation window; 66, winding roller; 67, driving motor; 111, preheating section. DETAILED DESCRIPTION

[0052] The present application is further illustrated by the following examples, which are intended to more clearly demonstrate the technical solutions of the present application, and should not be understood as a limitation.

[0053] The preparation of carbon nanotubes is to carry out high-temperature reaction of raw materials containing hydrogen, catalyst precursor, growth promoter precursor and carbon source in a heating furnace, the catalyst precursor is decomposed, collides and reduced into catalyst particles, the carbon source is decomposed on the surface of the catalyst under the action of the catalyst, dissolves into the catalyst, diffuses and then precipitates carbon cap, the continuous supply of carbon source makes the carbon cap elongate to form carbon nanotubes, and the carbon nanotubes flow to the tail end of the reaction chamber with hydrogen, and finally form macroscopic single-walled carbon nanotubes of different morphologies such as thin film or sponge.

[0054] As shown in Figures 1 to 6 A tubular heating furnace for preparing carbon nanotubes includes at least one furnace tube 1 and a heat insulating body 2 arranged on the outer periphery of the furnace tube 1. The furnace tube 1 is a high-temperature-resistant pipeline, which can be one or multiple arranged side by side. Two furnace tubes 1 arranged side by side in the heat insulating body 2 are shown as an example. The heat insulating body 2 is made of high-temperature-resistant and low-thermal-conductivity insulation material, which can be integrally formed or spliced. One end of the furnace tube 1 is the feeding end, and the other end is the discharging end. The heat insulating body 2 has a space with the outer wall of the furnace tube 1, which is divided into multiple heating cavities 21 arranged along the length direction of the furnace tube 1, so that the space in the furnace tube 1 corresponds to form multiple temperature zones. The heating cavities 21 are provided with heating elements and temperature detection elements. The furnace tube 1 is used to accommodate reactants and provide heating and reaction space. The multiple heating cavities 21 arranged between the heat insulating body 2 and the furnace tube 1 can control different heating temperatures. The heating elements heat the heating cavities 21, and the temperature detection elements detect the temperature of the heating cavities 21 to provide the basis for temperature control.

[0055] 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 the pipeline along with the gas flow at the feeding end.

[0056] In some embodiments, the carbon source gas can be introduced into the furnace tube 1 through the pipeline at the feeding end. In other embodiments, the carbon source gas can also be introduced into the furnace tube 1 from the side wall of the furnace tube 1 at one point or multiple points.

[0057] Preferably, as shown in Figure 6 and Figure 7 Multiple gas inlet pipelines 11 are also led out on the side wall of the furnace tube 1 and along the length direction of the furnace tube 1, each of which is in communication with the inside of the furnace tube 1 to supply raw material gas to different parts of the furnace tube 1. It is found through experiments that the demand for hydrogen and carbon source is different at different stages in the process of growing single-walled carbon nanotubes by the floating catalyst method. The structure of multiple gas inlets along the side wall of the furnace tube 1 can introduce the appropriate raw material gas into different temperature zones at different stages, which can significantly improve the utilization rate of the carbon source. The time for the catalyst particles to agglomerate and grow before starting to grow is also shorter, thereby improving the yield of single-walled carbon nanotubes.

[0058] Preferably, as shown in Figure 5 and Figure 6 , the heating elements are electric heating tubes 22, and each heating cavity 21 is provided with independently controllable heating elements. The electric heating tubes 22 as heating elements, each or each group can be independently controlled in the respective heating cavity 21, which enables the operator to accurately set different temperature zones along the length direction of the furnace tube 1, so as to optimize the temperature conditions in the process of carbon nanotube growth, and improve the quality and yield of the product.

[0059] Preferably, as shown in Figure 5 and Figure 6 , in each heating cavity 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 cavity 21, a temperature detection element is provided, which is a thermocouple, and the detection end of the thermocouple is directed into the heating cavity 21 from the inner wall of the heat insulating body 2, which ensures the accuracy and real-time of temperature measurement, and further provides accurate temperature feedback for temperature regulation.

[0060] As shown in Figure 7 , each gas inlet pipe 11 has a preheating section 111 adjacent to the outer wall of the furnace tube 1, and the preheating section 111 passes through the heating cavity 21, so that the gas transported by the pipe can be preheated before entering the furnace tube 1, thereby reducing the temperature fluctuation inside the furnace tube 1, and improving the reaction efficiency.

[0061] As shown in Figure 6 , the furnace tube 1 is connected to one gas inlet pipe 11 corresponding to each temperature zone, and each gas inlet pipe 11 has an independent gas inlet end to independently control the supply of raw gas for each temperature zone. In this way, the supply of raw gas can be accurately controlled according to the different needs of carbon nanotube growth in different temperature zones, and this design improves the utilization efficiency of carbon source and the growth quality of carbon nanotubes.

[0062] Preferably, as shown in Figure 3 , Figure 4 and Figure 8As shown, the tubular heating furnace further comprises a cooling cover 3 arranged outside the heat insulator 2, the cooling cover 3 comprises an inner cover 31 enveloping the heat insulator 2 and an outer cover 32 enveloping the inner cover 31; a cooling cavity 33 containing cooling medium is formed between the inner cover 31 and the outer cover 32, and a first liquid inlet 34 and a first liquid outlet 35 are arranged on the outer cover 32; the first liquid inlet 34 and the first liquid outlet 35 are both in communication with the cooling cavity 33. By adding a cooling system composed of inner and outer layers outside the heat insulator 2, the cooling cavity 33 can contain cooling medium, the cooling liquid is injected through the first liquid inlet 34, discharged from the first liquid outlet 35 after passing through the cooling cavity 33, effectively taking away the excess heat generated during the operation of the heating furnace, protecting the external equipment and environment from high temperature, and at the same time helping to control the overall temperature distribution of the heating furnace.

[0063] Preferably, as shown in Figure 4 , 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 the cooling medium such as water and heat-conducting oil to fully cool the cooling cavity 33, promotes the circulation of the cooling medium, and improves the cooling efficiency.

[0064] Preferably, as shown in Figure 6 , Figure 7 and Figure 9 , at the feeding end, the outer wall of the furnace tube 1 is further wrapped with a cooling jacket 4, the cooling jacket 4 can contain cooling medium, the lower part of the cooling jacket 4 is provided with a second liquid inlet 41, and the upper part of the cooling jacket 4 is provided with a second liquid outlet 42. The cooling medium enters from the second liquid inlet 41 at the lower part of the cooling jacket 4, and flows out from the second liquid outlet 42 at the upper part after absorbing the heat emitted by the furnace tube 1, which helps to reduce the temperature at the feeding end and protect the safety of the operator.

[0065] Preferably, as shown in Figure 1 and Figure 2 , the outer part of the cooling cover 3 is further provided with a protective shell 5. The protective shell 5 blocks the circumferential side of the furnace tube 1 and leaves an operation window at the feeding end of the furnace tube 1.

[0066] As described 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 volatilizes into the atmosphere in the furnace tube 1 and reacts with the raw material gas, and the carbon source grows into carbon nanotubes in a specific arrangement. However, due to the limitations of contact and dispersion, the utilization efficiency of the catalyst is not high, and the catalytic activity is not fully utilized. Therefore, as shown in Figure 7As shown, a conduit 15 is arranged to extend into the furnace tube 1 at the feed end of the furnace tube 1, and an atomizing nozzle 16 is connected to the end of the conduit 15 inside the furnace tube 1. The catalyst precursor can be uniformly dispersed into the reaction atmosphere in the furnace tube 1 through the atomizing nozzle, increasing the contact between the catalyst and the raw material gas, thereby promoting more efficient catalytic reaction and promoting efficient and uniform growth of carbon nanotubes. On the other hand, the catalyst precursor is preheated during its flow in the furnace tube 1, reducing agglomeration, providing more active sites, and achieving efficient and high-purity single-walled carbon nanotube growth.

[0067] Preferably, the atomizing nozzle 16 is located within a temperature zone close to the feed end.

[0068] Preferably, as Figure 9 shown, the feed end of the furnace tube 1 has a flange opening, and the conduit 15 is provided with a sealing connecting plate, and the flange opening of the feed end of the furnace tube 1 is detachably connected to the sealing connecting plate on the conduit 15, for example, through bolts, clamps or other connecting members.

[0069] The single-walled carbon nanotubes grown based on the floating catalyst chemical vapor deposition method are in a flocculent form, have a light material quality, and have a large volume, which are easy to adhere to the low-temperature area of the reaction chamber, causing the furnace tube 1 to be blocked, the pressure in the furnace to be increased, and the continuousness and safety of production to be affected.

[0070] As shown in Figure 1 , Figure 10 , Figure 11 and Figure 12 , at the discharge end of the tubular furnace, a carbon nanotube discharge device is provided. The discharge device includes a collection bin 6, which has a collection cavity inside that is in communication with the discharge port of the tubular furnace, i.e., the furnace tube 1 is in communication with the collection bin 6; an operating port 61 is provided on the collection bin 6, and a flexible pipe 62 is connected to the operating port 61, and the operating port 61 is sealingly connected to the proximal end of the flexible pipe 62; at least one operating rod 63 extends through the flexible pipe 62 and into the collection cavity, and the distal end of the flexible pipe 62 is sealingly connected to the operating rod 63; and a discharge interface is provided at the bottom of the collection bin 6.

[0071] The discharge device is provided with a collecting bin 6 at the discharge port of the furnace tube 1, and the operating port 61 is connected with at least one operating rod 63 extending into the interior of the collecting bin through a flexible pipe 62, which allows the operator to safely transfer and collect the flocculent single-walled carbon nanotubes which are prone to cause the furnace tube to be blocked during the growth process outside. In addition, a transfer tank can be connected at the discharge interface, and when the flocculent single-walled carbon nanotubes in the collecting bin 6 accumulate to a certain amount, the operator can use the operating rod 63 to push the flocculent single-walled carbon nanotubes to the transfer tank, and then cut off the connection between the discharge 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 discharge is realized 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.

[0072] Preferably, the flexible pipe 62 is an elastic corrugated pipe made of metal material. The elastic corrugated pipe made of metal material not only has good high-temperature resistance and can withstand the high-temperature environment during the operation of the heating furnace, but also has good flexibility and stretchability, which can adapt to the position adjustment or slight movement of the collecting bin 6, and at the same time allows the operating rod 63 to have a larger linear movement and rotation movement space during the operation. The metal corrugated pipe also generally has high mechanical strength and durability, which can effectively prevent deformation or rupture caused by external pressure changes, and ensure the safety and stability of the operation.

[0073] As shown in Figure 12 , the size of the distal end and the proximal end of the flexible pipe 62 can be consistent, forming a pipe with a substantially uniform diameter. More preferably, the size of the proximal end of the flexible pipe 62 can be larger than the distal end, forming a flared shape, so that the operating rod 63 has a larger operating space and improves the flexibility of the operating rod 63.

[0074] Preferably, as shown in Figure 12 , the end of the operating port 61 has a flange port, the proximal end of the flexible pipe 62 has a flange port, and the flange port of the end of the operating port 61 is detachably connected with the flange port of the proximal end of the flexible pipe 62, for example, through bolts, clamps or other connecting members to realize detachable connection, which not only ensures the sealing, but also allows the operating rod 63 to be easily replaced or taken out as needed, thereby enhancing the operation flexibility of the equipment.

[0075] Preferably, as shown in Figure 12 , the distal end of the operating port 61 has a flange port, and a sealing connecting plate is arranged on the rod body of the operating rod 63, and the flange port of the distal end of the operating port 61 is detachably connected with the sealing connecting plate on the operating rod 63. Similarly, the detachable connection can also be realized through bolts, clamps or other connecting members, which facilitates quick assembly and disassembly, and is convenient for maintenance and cleaning.

[0076] Preferably, as shown in Figure 12As shown, the end of the operating rod 63 inside the collecting bin 6 has a hook, and the end of the operating rod 63 outside the collecting bin 6 has a handle. The hook part of the operating rod 63 can be used to hook or move the carbon nanotube flocculation inside the collecting bin 6, and the handle is convenient for the operator to control the action of the operating rod 63 outside the collecting bin 6, which improves the operation convenience and safety.

[0077] Preferably, as shown, Figure 11 Preferably, as shown, the bottom of the collecting bin 6 is tapered and has a discharge port at the bottom; the side of the collecting bin 6 opposite to the discharge port of the tubular heating furnace is provided with a sealing bin door 64, and the operating port 61 is arranged on the sealing bin door 64.

[0078] Preferably, as shown, Figure 11 Preferably, as shown, at least one observation window 65 is arranged on the collecting bin 6, and the observation window 65 and the operating port 61 are located on the same side of the collecting bin 6.

[0079] Preferably, as shown, Figure 11 and Figure 13 Preferably, as shown, a winding roller 66 is rotatably arranged in the collecting bin 6, and the winding roller 66 is driven to rotate by a driving motor 67 arranged on the outer wall of the collecting bin 6. In this way, the prepared carbon nanotube flocculation can be orderly wound on the roller, avoiding the accumulation and confusion of the material, and after winding, the carbon nanotube flocculation can be easily pushed down by the operating rod 63 as a whole, which is convenient for full collection and improves the collection efficiency and neatness.

[0080] Preferably, as shown, Figure 11 Preferably, as shown, the bin wall of the collecting bin 6 has a sandwich space, and a circulating cooling medium can be kept in the sandwich space to prevent the temperature of the outer wall of the collecting bin 6 from being too high.

[0081] The above embodiments are exemplary, and the purpose is to illustrate the technical concept and characteristics of the present application, so that those skilled in the art can understand the content of the present application and implement it, and the protection scope of the present application cannot be limited thereto. Any equivalent changes or modifications made according to the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A heating furnace for preparing carbon nanotubes, characterized in that: It includes a furnace tube (1) and a heat insulation body (2) disposed on the outer periphery of the furnace tube (1); one end of the furnace tube (1) is the feed end and the other end is the discharge end; there is a gap between the heat insulation body (2) and the outer wall of the furnace tube (1), the gap is divided into multiple heating chambers (21) arranged along the length direction of the furnace tube (1), so that the space inside the furnace tube (1) forms multiple temperature zones; heating elements and temperature detection elements are provided in the heating chambers (21); 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) inside the furnace tube (1); Multiple air inlet pipes (11) are also extended from the side wall of the furnace tube (1) and along the length of the furnace tube (1). Each air inlet pipe (11) is connected to the interior of the furnace tube (1) to supply raw material gas to different parts inside the furnace tube (1). Each of the air inlet pipes (11) has a preheating section (111) on the outer wall of the furnace tube (1), the preheating section (111) passing through the heating chamber (21). The furnace tube (1) is connected to an air inlet pipe (11) for each temperature zone, and each air inlet pipe (11) has an independent air inlet end to independently control the supply of raw material gas for each temperature zone. A carbon nanotube discharge device is provided at the discharge end of the tubular heating furnace. The discharge device includes a collection chamber (6), which has a collection cavity communicating with the discharge port of the tubular heating furnace. An operation port (61) is provided in the collection chamber (6), and a flexible pipe (62) is connected to the operation port (61). The operation port (61) is sealed to the proximal end of the flexible pipe (62). At least one operating lever (63) extends through the flexible pipe (62) into the collection cavity, and the distal end of the flexible pipe (62) is sealed to the operating lever (63). A discharge interface is provided at the bottom of the collection chamber (6). The flexible pipe (62) is a metal elastic corrugated pipe; 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, and a sealing connecting plate is provided on the rod of the control lever (63), and the flange at the distal end of the operating port (61) is detachably connected to the sealing connecting plate on the control lever (63); the end of the control lever (63) located inside the collection chamber (6) has a hook, and the end of the control lever (63) located outside the collection chamber (6) has a handle; the distal end and the proximal end of the flexible pipe (62) are the same size; or the proximal end of the flexible pipe (62) is larger than the distal end, forming a flared shape.

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

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

4. The heating furnace for preparing carbon nanotubes according to claim 1, characterized in that: A winding roller (66) is rotatably provided inside the collection bin (6), and the winding roller (66) is driven to rotate by a drive motor (67) installed on the outer wall of the collection bin (6).

5. A method for preparing carbon nanotubes, characterized in that: The carbon nanotubes are prepared using the heating furnace described in any one of claims 1 to 4.

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