Apparatus and method for preparing carbon nanotube cylinders

Abstract

This invention discloses an apparatus and method for preparing carbon nanotube cylindrical structures. The output end of a syringe is connected to the input end of an ultrasonic nebulizer, which is then connected to the input end of a tubular furnace reactor. The ultrasonic nebulizer is connected to a carrier gas cylinder via a gas washing bottle, and the carrier gas cylinder is connected to the tubular furnace reactor via a gas delivery tube. A cylindrical structure stretching and collection system is used to collect the reactants from the tubular furnace reactor. The method includes preparing a mixed solution, drawing the mixed solution into the syringe, introducing argon and hydrogen gas at preset flow rates into the apparatus, injecting the mixed solution into the ultrasonic nebulizer, atomizing the mixed solution into a mist-like reaction liquid in the ultrasonic nebulizer, and then transporting it to the tubular furnace reactor. The mist-like reaction liquid reacts in the tubular furnace reactor to generate carbon nanotube cylindrical structures. This invention provides a precisely controllable, uniform, continuous, and stable supply of carbon source and carrier gas for carbon nanotube growth, enabling the continuous preparation of carbon nanotube cylindrical structures.

Description

Technical Field

[0001] This invention relates to a nanomaterial preparation device and method in the field of nanomaterial technology, and in particular to a preparation device and method for carbon nanotube cylindrical materials. Background Technology

[0002] Carbon nanotube tubes are continuous cylindrical materials assembled from ultra-long carbon nanotubes. Through twisting and densification processes, carbon nanotube fibers can be prepared, serving as an intermediate product in the CVD (Chemical Vapor Deposition) method for carbon nanotube fiber production. Carbon nanotube fibers possess excellent mechanical, electrical, and thermal properties, making them a novel structural and functional integrated material and attracting significant research attention as macroscopic carbon nanotubes. Numerous studies have demonstrated the broad application prospects of carbon nanotube fibers in structural-functional integrated composite materials, fibrous energy devices, artificial muscles, and lightweight conductive cables. In recent years, researchers have continuously developed continuous spinning processes for carbon nanotube fibers, revealing the process-structure-performance relationship and exploring engineering applications. Currently, the main methods for preparing carbon nanotube fibers include wet spinning based on the solidification process, spinning using vertical arrays of carbon nanotubes, and direct spinning based on chemical vapor deposition (CVD) growth. Among these, CVD direct spinning is the most promising method for industrial-scale production of high-quality carbon nanotube fibers and has attracted considerable research attention.

[0003] Patent "Apparatus and Method for Preparing Vertical Continuous Carbon Nanotube Fibers" (Application No.: CN201510874269) provides an apparatus for preparing vertical continuous carbon nanotube fibers, which includes a carbon source injector, a tubular furnace, and a collection box connected to the tubular furnace. Patent "System and Method for Continuous Preparation of Carbon Nanotube Fibers Based on Floating Catalytic CVD" (Application No.: CN201911356576.0) discloses a system and method for continuous preparation of carbon nanotube fibers based on a floating catalytic CVD method. The system includes a gasification sample introduction device, a synthesis reaction device, and a fiber winding and collection device. The patent "Apparatus and Method for Preparing Continuous Carbon Nanotube Fibers by Liquid-Sealed Gas-Phase Flow Catalytic Reaction" (Application No.: CN200710059491.7) discloses an apparatus and method for preparing continuous carbon nanotube fibers by liquid-sealed gas-phase flow catalytic reaction. The apparatus is: an apparatus for preparing continuous carbon nanotube fibers by liquid-sealed gas-phase flow catalytic reaction, mainly including a synthesis reactor composed of a tubular furnace and a quartz tube. The feature is that it also includes a liquid tank containing a sealed liquid medium. The sealed liquid tank is connected to the gas outlet end of the quartz tube of the synthesis reactor through a flange. A micro-injector is located at the gas inlet of the synthesis reactor, and the nozzle is located at the gas inlet end of the quartz tube. Patent "A System and Method for Large-Scale Preparation of Carbon Nanotube Fibers in a Safe Atmosphere" (Application No.: CN202110650373.3) discloses a system and method for large-scale preparation of carbon nanotube fibers in a safe atmosphere. The system includes a carbon nanotube fiber growth unit and a carbon nanotube fiber collection unit. The carbon nanotube fiber growth unit also cooperates with a carbon source injection unit and an airflow control unit. The carbon nanotube fiber growth unit includes multiple growth chambers separated from each other. A cooling mechanism and an air-sealing mechanism are provided at the outlet of each growth chamber to improve the process safety during large-scale preparation. Patent "A Method for Large-Scale Preparation of Continuous Carbon Nanotube Fibers" (Application No.: CN103628183A) relates to a method for large-scale preparation of continuous carbon nanotube fibers. It employs multiple furnaces connected in series, multiple uses of airflow, and simultaneous and stable continuous spinning of carbon nanotube fibers across multiple furnaces. LG Chem Corporation (Apparatus for Manufacturing Carbon Nanotube Fibers CN201680003916.X) has invented an apparatus for manufacturing carbon nanotube fibers, comprising: a cylindrical high-temperature reactor body having a reaction zone; an inlet for feeding spinning raw material and carrier gas into the reaction zone of the body; a heater for heating the reaction zone; an outlet disposed at the bottom of the body for discharging carbon nanotube fibers; a winding machine for collecting the discharged carbon nanotube fibers; a guide disposed between the outlet and the winding machine; and a voltage supply for applying voltage to the guide, wherein the voltage is applied to the discharged carbon nanotube fibers to remove impurities from the carbon nanotube fibers.

[0004] Currently, there are numerous reports both domestically and internationally on the fabrication equipment and methods for carbon nanotube fibers using chemical vapor deposition (CVD). However, existing CVD methods for preparing carbon nanotube fibers mainly employ vertical and horizontal tube designs. Horizontal tube designs suffer from the problem of carbon nanotubes easily adhering to the tube wall, leading to tube breakage and fiber discontinuity. Furthermore, the reaction is susceptible to external atmospheric influences, posing a risk of self-sealing and explosion of the tubes. While vertical tube designs, using a vertical furnace, more easily achieve continuous spinning, current vertical tube designs primarily inject material from the top, requiring a sufficiently large gas flow rate to ensure continuous spinning. Otherwise, gas in the pipeline is prone to backflow due to thermal convection and gravity, posing a significant risk and being difficult to control effectively. Summary of the Invention

[0005] In order to solve the main problems existing in the current vertical and horizontal tube furnace chemical vapor deposition methods for preparing carbon nanotube fibers, the purpose of this invention is to design a device and method for preparing carbon nanotube cylindrical materials.

[0006] The technical solution of this invention is as follows:

[0007] I. An apparatus for preparing carbon nanotube tubular materials:

[0008] It includes a syringe, an ultrasonic nebulizer, a gas washing bottle, a carrier gas delivery system, a tubular furnace reactor, and a cylindrical material stretching and collection system; the output end of the syringe is connected to the input end of the ultrasonic nebulizer, the output end of the ultrasonic nebulizer is connected to the input end of the tubular furnace reactor, the carrier gas delivery system is connected to the input ends of the ultrasonic nebulizer and the tubular furnace reactor respectively, and the cylindrical material stretching and collection system collects carbon nanotube cylindrical materials in the tubular furnace reactor.

[0009] The carrier gas delivery system includes two carrier gas cylinders, a gas washing bottle, and a three-way connector. Both the top of the gas washing bottle and the top of the ultrasonic atomizer have two ports. The outputs of the two carrier gas cylinders are connected to the two inlets of the three-way connector via two gas guide pipes. The outlet of the three-way connector is connected to one port of the gas washing bottle and the input port at the bottom of the tubular furnace reactor via two gas guide pipes. A flow meter is installed on the gas guide pipe from the outlet of the three-way connector to the tubular furnace reactor, and a flow meter is also installed on the gas guide pipe from the outlet of the three-way connector to the gas washing bottle. The other port of the gas washing bottle is connected to one port at the top of the ultrasonic atomizer via a gas guide pipe. The other port at the top of the ultrasonic atomizer is connected to the input port at the bottom of the tubular furnace reactor via a raw material gas delivery pipe. An ultrasonic transducer is installed in the middle of the ultrasonic atomizer.

[0010] The ultrasonic nebulizer is placed on the ground. A port is opened in the middle of the ultrasonic nebulizer. The output end of the syringe is connected to the port in the middle of the ultrasonic nebulizer through an infusion tubing.

[0011] A flange is fixedly installed at the bottom of the tubular furnace reactor. The bottom end of the raw material gas supply pipe is connected to the top of the ultrasonic atomizer. The top end of the raw material gas supply pipe passes through the flange and is connected to the cavity of the quartz tube in the middle of the tubular furnace reactor.

[0012] The vibration frequency of the ultrasonic atomizer is 1.0MHz to 1.7MHz.

[0013] The syringe is made of stainless steel or quartz.

[0014] II. A method for preparing a carbon nanotube cylindrical material used in the device of the present invention, comprising the following steps:

[0015] Step 1: Prepare a mixed solution by combining carbon source, catalyst, accelerator and water, and then draw the mixed solution into a syringe.

[0016] Step 2: Open the two carrier gas cylinders and introduce argon and hydrogen gas into the device at the preset flow rates;

[0017] Step 3: Inject the mixed solution into the ultrasonic nebulizer using a syringe, while controlling the injection rate of the mixed solution to be 20ml / h~40ml / h;

[0018] Step 4: The mixed solution is atomized in an ultrasonic atomizer to become a mist reaction liquid, and then transported to a tubular furnace reactor. The mist reaction liquid reacts inside the quartz tube of the tubular furnace reactor to generate carbon nanotubes. Finally, the carbon nanotubes are removed using an iron wire and tubular material stretching and collection system.

[0019] The mixed solution in step 1 is prepared according to the following mass percentages: carbon source 91.0-98.4%, catalyst 1.0-2.5%, promoter 0.6-1.5%, and water 0-5.0%.

[0020] In step 2, the flow rate of hydrogen is 400–800 sccm, and the flow rate of argon is 200–600 sccm.

[0021] In step 4, the temperature at which the carbon nanotubes are generated in the tubular furnace reactor is 900~1200℃.

[0022] The carbon source is ethanol, acetone, ethanol, ethylene glycol, or n-hexane; the catalyst is a compound of iron, cobalt, or nickel; and the promoter is methanol, acetone, or ethanol.

[0023] This invention employs a vertical chimney-type high-temperature tubular furnace reactor. A syringe is located at the bottom of the device, feeding raw materials from the middle of the reactor, while carbon nanotubes are discharged from the top. An ultrasonic atomizer introduces the carbon source / catalyst into the reaction zone of the synthesis reactor in the form of atomized gas, providing a precisely controlled, uniform, stable, and continuous supply of carbon source for the subsequent carbon nanotube growth, thus achieving the continuous preparation of uniform carbon nanotubes. The carrier gas delivery system includes a gas washing bottle, which ensures that the ethanol vapor pressure within the atomization chamber of the ultrasonic atomizer remains at a high level, thereby guaranteeing the atomization effect of the catalyst. The carrier gas delivery system also includes a gas guide pipe that directly enters the reaction zone, solving the problem of high-temperature carbonization of ethanol contaminating the tubular furnace reactor during pre-experiment exhaust. The tubular material stretching and collection system consists of a continuously variable speed winding machine, allowing for the collection of carbon nanotubes with different stretching ratios by adjusting the winding machine's speed. This significantly improves the various properties of the tubular materials, enabling the continuous collection of high-performance carbon nanotubes.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. The ultrasonic atomizer can pre-atomize liquid carbon source / catalyst into small-diameter droplets and control the supply rate of liquid carbon source / catalyst and the carrier gas flow rate, so that the atomized carbon source / catalyst and the carrier gas are fully and uniformly mixed before entering the pyrolysis reaction zone of the tubular furnace reactor. This provides a precise, controllable, uniform, continuous and stable supply of carbon source and carrier gas for carbon nanotube growth, thereby realizing the continuous preparation of carbon nanotube cylindrical materials.

[0026] 2. The carrier gas delivery system can achieve independent control of the two gas paths: the amount of atomized carbon source / catalyst entering and the amount of carrier gas entering. This ensures both uniform carrying of atomized raw materials and accurate control of the total gas flow.

[0027] 3. The tubular furnace reactor of this invention, with its vertical furnace body, facilitates rapid and large-scale preparation of carbon nanotubes. Material is injected from the bottom, and the formed carbon nanotubes overflow from the top under the action of a carrier gas. This invention utilizes a chimney-like smoke transport system, resulting in a small gas flow rate and minimal impact from the external environment, making the reaction safe and reliable.

[0028] 4. This invention utilizes the characteristic that the carrier gas density is lower than that of air, allowing the hot airflow to carry the cylindrical object to the surface, thus avoiding the problems of adhesion and breakage of the cylindrical object.

[0029] 5. The cylindrical material drawing and collection system of the present invention can collect carbon nanotube cylindrical materials with different drawing ratios by adjusting the rotation speed of the winding machine, thereby improving the various properties of the cylindrical materials and realizing the continuous collection of high-performance carbon nanotube cylindrical materials. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the carbon nanotube cylindrical preparation device used in this invention.

[0031] Figure 2 This is a schematic diagram of the ultrasonic atomizer described in this invention.

[0032] Figure 3 Image of the carbon nanotube tubular structure prepared in Example 1.

[0033] Figure 4 This is a schematic diagram of the carbon nanotube tubular structure prepared in Example 1 using SEM.

[0034] Figure 5 This is a schematic diagram of the carbon nanotube tubular structure prepared in Example 2 using SEM.

[0035] In the diagram: 1. Syringe; 2. Ultrasonic nebulizer; 3. Gas washing bottle; 4. Carrier gas delivery system; 5. Flange; 6. Tube furnace reactor; 7. Winding machine. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0037] like Figure 1 As shown, the apparatus includes a syringe 1, an ultrasonic nebulizer 2, a gas washing bottle 3, a carrier gas delivery system 4, a tubular furnace reactor 6, and a cylindrical material stretching and collection system. The output end of the syringe 1 is connected to the input end of the ultrasonic nebulizer 2, and the output end of the ultrasonic nebulizer 2 is connected to the input end of the tubular furnace reactor 6. The carrier gas delivery system 4 is connected to the input ends of both the ultrasonic nebulizer 2 and the tubular furnace reactor 6. The cylindrical material stretching and collection system is used to collect the reactants produced by the tubular furnace reactor 6.

[0038] The syringe 1 is used to continuously inject liquid raw materials into the ultrasonic nebulizer 2.

[0039] The carrier gas delivery system 4 includes two carrier gas cylinders, a gas washing bottle 3, and a three-way connector. Both the top of the gas washing bottle 3 and the top of the ultrasonic atomizer 2 have two ports. The outputs of the two carrier gas cylinders are connected to the two inlets of the three-way connector via two gas guide pipes. Each gas guide pipe from the carrier gas cylinder to the inlet of the three-way connector is equipped with a switch valve. The outlet of the three-way connector is connected to one port of the gas washing bottle 3 and the input port at the bottom of the tubular furnace reactor 6 via two gas guide pipes. A flow meter is installed on the gas guide pipe from the outlet of the three-way connector to the tubular furnace reactor 6, and on the gas guide pipe from the outlet of the three-way connector to the gas washing bottle 3. The other port of the gas washing bottle 3 is connected to one port at the top of the ultrasonic atomizer 2 via a gas guide pipe. The other port at the top of the ultrasonic atomizer 2 is connected to the input port at the bottom of the tubular furnace reactor 6 via a raw material gas delivery pipe. An ultrasonic vibrator is installed in the middle of the ultrasonic atomizer 2.

[0040] The gas washing bottle 3 and the ultrasonic nebulizer 2 are connected by a gas guide tube that does not extend into the solution, while the gas washing bottle 3 and the three-way connector are connected by a gas guide tube that extends into the solution.

[0041] like Figure 2 As shown, the ultrasonic nebulizer 2 is placed on the ground. The ultrasonic nebulizer 2 has a port in the middle. The output end of the syringe 1 is connected to the port in the middle of the ultrasonic nebulizer 2 through an infusion tubing.

[0042] The ultrasonic atomizer 2 includes a cylindrical atomizing chamber and a rectangular base. The atomizing chamber is mounted on the base, and the ultrasonic transducer is mounted on the inner top surface of the base. The port at the bottom of the atomizing chamber is connected to a syringe 1, allowing liquid raw materials to be introduced. The top of the ultrasonic atomizer 2 is equipped with two stainless steel gas pipes. One pipe receives carrier gas from the carrier gas delivery system 4, and the other pipe, via a flange 5, introduces the atomized raw material into the tubular furnace reactor 6. The carrier gas forms a stable loop between the two pipes, stably carrying the atomized liquid raw material from the upper end of the high-frequency ultrasonic transducer to the tubular furnace reactor 6. Through the stable supply of liquid raw material and carrier gas, a stable and continuous supply of atomized material can be achieved.

[0043] Two carrier gas cylinders, one containing H2 and the other containing Ar. The gas exiting the carrier gas cylinders is split into two streams after passing through a stainless steel tee connector. One stream connects to the tubular furnace reactor 6, and the other stream connects to the gas washing bottle 3 containing ethanol. The outlet of the gas washing bottle 3 is connected to the inlet of the atomization chamber of the ultrasonic nebulizer 2 via a gas guide tube. Both streams are equipped with independent flow meters to achieve independent control of the two gas streams.

[0044] The central part of the tubular furnace reactor 6 is a quartz tube. Material atomized by the ultrasonic atomizer 2 is continuously and stably fed into the tubular furnace reactor 6 along with the carrier gas via the raw material gas supply pipe. Liquid raw materials and carrier gas are fed into the tubular furnace reactor 6 from the bottom, where they undergo pyrolysis and reaction to generate carbon nanotubes. The carbon nanotubes cross-link to form carbon nanotube cylinders, which overflow from the top of the tubular furnace reactor 6, resembling a chimney. The cylinder stretching and collection system includes a winding machine 7. The top of the tubular furnace reactor 6 is the carbon nanotube outlet. The carbon nanotube cylinders are obtained under the stretching action of the winding machine 7, enabling the collection of carbon nanotube cylinders with different stretching ratios.

[0045] A uniformly mixed suspension of liquid carbon source, catalyst, promoter, and water (i.e., liquid raw material) is ejected from the tip of syringe 1 at a low flow rate and injected into ultrasonic atomizer 2 with controllable power. This atomizes the liquid raw material and mixes it with the carrier gas. The mixture is then continuously transported through a gas guide tube to the quartz tube of tubular furnace reactor 6. The quartz tube is cracked at the bottom, and cylindrical carbon nanotubes are generated in the middle of the tube. These nanotubes overflow to the top of the tube under the propulsion of the airflow. The cylindrical carbon nanotubes are then drawn by winding machine 7, allowing for the collection of cylindrical carbon nanotubes with different draw ratios.

[0046] A flange 5 is fixedly installed at the bottom of the tubular furnace reactor 6. The bottom end of the raw material gas supply pipe is connected to the top of the ultrasonic atomizer 2. The top end of the raw material gas supply pipe passes through the flange 5 and is connected to the cavity of the quartz tube in the middle of the tubular furnace reactor 6.

[0047] The vibration frequency of the ultrasonic atomizer 2 is 1.0MHz to 1.7MHz. The liquid feed rate should be changed with the vibration frequency. The liquid feed rate of the liquid raw material is 15ml / h to 35ml / h.

[0048] The syringe 1 is made of stainless steel or quartz.

[0049] The implementation process of the embodiments of the present invention is as follows, including the following steps: Example

[0050] Step 1: Dissolve 0.86g of ferrocene and 0.37g of thiophene in 46.07g of ethanol to prepare a mixed solution, and then draw the above mixed solution into syringe 1;

[0051] Step 2: Open the two carrier gas cylinders and introduce argon gas at a flow rate of 400 sccm and hydrogen gas at a flow rate of 500 sccm into the device;

[0052] Step 2 is as follows: First, check the airtightness of the device. Then, set the temperature of the central temperature zone of the tubular furnace reactor 6 to 1200℃. After the temperature of the central temperature zone reaches 1200℃, turn on the flow meter in the device and pass 900 sccm of Ar for 10 minutes to purge the air inside the tubular furnace reactor 6; at the same time, pass 50 sccm of H2 for 10 minutes to consume the residual oxygen in the tube. Then, increase the H2 flow rate to 200 sccm and decrease the Ar flow rate to 700 sccm; after two minutes, increase the H2 flow rate to 400 sccm and decrease the Ar flow rate to 500 sccm; after two minutes, increase the H2 flow rate to 500 sccm and decrease the Ar flow rate to 400 sccm, and then maintain this flow rate for 10 minutes to stabilize the gas field inside the tube.

[0053] Step 3: Inject the mixed solution into the ultrasonic nebulizer 2 using syringe 1, while controlling the injection rate of the mixed solution to be 30ml / h.

[0054] Step 4: After the mixed solution is injected into the ultrasonic atomizer 2, a liquid film forms on the surface of the ultrasonic transducer. The mixed solution is atomized in the ultrasonic atomizer 2 and transformed into a mist-like reaction liquid, which is then transported to the tubular furnace reactor 6. The mist-like reaction liquid reacts inside the quartz tube of the tubular furnace reactor 6 to generate carbon nanotubes. Finally, the carbon nanotubes are removed using an iron wire and a winding machine 7. Figure 3 As shown, the carbon nanotube tubular structure is intact and continuous, without any damage.

[0055] Step 4 specifically involves: transferring the atomized reaction liquid to a tubular furnace reactor 6 filled with an argon-hydrogen mixture. At the bottom of the quartz tube, the reaction liquid vaporizes and decomposes (the decomposition temperature should be above 400 degrees Celsius), producing a white aerogel-like substance. This substance then reaches the middle of the quartz tube, producing black cylindrical carbon nanotubes (the reaction temperature is approximately 1200 degrees Celsius). When the generated carbon nanotube cylindrical material is carried by the airflow to the upper end of the quartz tube, it is manually pulled through a winding machine 7 using a wire.

[0056] SEM micrographs of carbon nanotube tubular structures, such as Figure 4 As shown, the carbon nanotubes produced by the method of the present invention have long carbon nanotube length, large aspect ratio and good orientation. Example

[0057] Step 1: Dissolve 0.86g of ferrocene and 0.37g of thiophene in 46.07g of ethanol to prepare a mixed solution, and then draw the above mixed solution into syringe 1;

[0058] Step 2: Open the two carrier gas cylinders and introduce argon gas at a flow rate of 500 sccm and hydrogen gas at a flow rate of 400 sccm into the device;

[0059] Step 2 is as follows: First, check the airtightness of the device. Then, set the temperature of the central temperature zone of the tubular furnace reactor 6 to 1200℃. After the temperature of the central temperature zone reaches 1200℃, turn on the flow meter in the device and pass 900 sccm of Ar for 10 minutes to purge the air inside the tubular furnace reactor 6; at the same time, pass 50 sccm of H2 for 10 minutes to consume the residual oxygen in the tube. Then, increase the H2 flow rate to 200 sccm and decrease the Ar flow rate to 700 sccm; after two minutes, increase the H2 flow rate to 400 sccm and decrease the Ar flow rate to 500 sccm; then maintain this flow rate for 10 minutes to stabilize the gas field inside the tube.

[0060] Step 3: Inject the mixed solution into the ultrasonic nebulizer 2 using syringe 1, while controlling the injection rate of the mixed solution to be 30ml / h.

[0061] Step 4: After the mixed solution is injected into the ultrasonic atomizer 2, a liquid film is formed on the surface of the ultrasonic transducer. The mixed solution is atomized in the ultrasonic atomizer 2 and transformed into a mist reaction liquid. Then it is transported to the tubular furnace reactor 6. The mist reaction liquid reacts inside the quartz tube of the tubular furnace reactor 6 to generate carbon nanotubes. Finally, the carbon nanotubes are removed using iron wire and a winding machine 7.

[0062] Step 4 specifically involves: transferring the atomized reaction liquid to a tubular furnace reactor 6 filled with an argon-hydrogen mixture. At the bottom of the quartz tube, the reaction liquid vaporizes and decomposes (the decomposition temperature should be above 400 degrees Celsius), producing a white aerogel-like substance. This substance then reaches the middle of the quartz tube, producing black cylindrical carbon nanotubes (the reaction temperature is approximately 1200 degrees Celsius). When the generated carbon nanotube cylindrical material is carried by the airflow to the upper end of the quartz tube, it is manually pulled through a winding machine 7 using a wire.

[0063] SEM micrographs of carbon nanotube tubular structures, such as Figure 5 As shown, carbon nanotubes have a large aspect ratio and good orientation.

[0064] In this invention, a mixed solution of carbon source, catalyst, promoter, and water is injected into an ultrasonic atomizer 2 via a syringe 1. The solution is carried into a quartz tube by a carrier gas flow. The atomized reaction liquid is first vaporized and then decomposed into atoms, forming carbon nanotubes inside the quartz tube. Subsequently, a cylindrical carbon nanotube film is formed inside the quartz tube and ejected upwards with the high-speed hot gas flow. The carbon nanotubes are then pulled out of the tubular furnace reactor 6 and collected by a winding machine 7 to obtain carbon nanotube cylindrical materials. The ultrasonic atomizer 2 can increase the contact area between the reaction liquid and the carrier gas, thereby improving the activity of the reactants. The bottom-up chimney-type tubular furnace reactor (6) uses the high flow rate of the high-temperature gas flow to carry the carbon nanotubes, so that the reaction liquid can reach the reaction zone faster after vaporization, reducing the generation of intermediate products and carrying the carbon nanotube cylindrical materials out from the top, greatly increasing the production rate of carbon nanotube cylindrical materials and increasing the output, enabling mass production of carbon nanotube cylindrical materials.

Claims

1. An apparatus for preparing carbon nanotube cylindrical materials, characterized in that: It includes a syringe (1), an ultrasonic nebulizer (2), a gas washing bottle (3), a carrier gas delivery system (4), a tubular furnace reactor (6), and a cylindrical material stretching and collection system; the output end of the syringe (1) is connected to the input end of the ultrasonic nebulizer (2), the output end of the ultrasonic nebulizer (2) is connected to the input end of the tubular furnace reactor (6), the carrier gas delivery system (4) is connected to the input ends of the ultrasonic nebulizer (2) and the tubular furnace reactor (6) respectively, and the cylindrical material stretching and collection system collects carbon nanotube cylindrical materials in the tubular furnace reactor (6); The carrier gas delivery system (4) includes two carrier gas cylinders, a gas washing cylinder (3), and a three-way connector. The top of the gas washing cylinder (3) and the top of the ultrasonic atomizer (2) are both provided with two ports. The output ends of the two carrier gas cylinders are respectively connected to the two inlets of the three-way connector through two gas guide pipes. The outlet of the three-way connector is respectively connected to one port of the gas washing cylinder (3) and the input end of the bottom of the tubular furnace reactor (6) through two gas guide pipes. A flow meter is provided on the gas guide pipe from the outlet of the three-way connector to the tubular furnace reactor (6). A flow meter is provided on the gas guide pipe from the outlet of the three-way connector to the gas washing cylinder (3). The other port of the gas washing cylinder (3) is connected to one port of the top of the ultrasonic atomizer (2) through a gas guide pipe. The other port of the top of the ultrasonic atomizer (2) is connected to the input end of the bottom of the tubular furnace reactor (6) through a raw material gas delivery pipe. An ultrasonic vibrator is provided in the middle of the ultrasonic atomizer (2). The ultrasonic nebulizer (2) is placed on the ground. A port is opened in the middle of the ultrasonic nebulizer (2). The output end of the syringe (1) is connected to the port in the middle of the ultrasonic nebulizer (2) through the infusion tube.

2. The apparatus for preparing carbon nanotube tubular materials according to claim 1, characterized in that: The bottom of the tubular furnace reactor (6) is fixedly installed with a flange (5), the bottom end of the raw material gas pipeline is connected to the top of the ultrasonic atomizer (2), and the top end of the raw material gas pipeline passes through the flange (5) and is connected to the cavity of the quartz tube in the middle of the tubular furnace reactor (6).

3. The apparatus for preparing carbon nanotube cylindrical materials according to claim 1, characterized in that: The vibration frequency of the ultrasonic atomizer (2) is 1.0MHz to 1.7MHz.

4. The apparatus for preparing carbon nanotube tubular materials according to claim 1, characterized in that: The syringe (1) is made of stainless steel or quartz.

5. A method for preparing a carbon nanotube cylindrical structure applicable to any one of the devices described in claims 1-4, characterized in that, Includes the following steps: Step 1: Prepare a mixed solution of carbon source, catalyst, promoter and water, and then draw the mixed solution into a syringe (1); Step 2: Open the two carrier gas cylinders and introduce argon and hydrogen gas into the device at the preset flow rates; Step 3: Inject the mixed solution into the ultrasonic nebulizer (2) using a syringe (1), while controlling the injection speed of the mixed solution to be 20ml / h~40ml / h. Step 4: The mixed solution is atomized in the ultrasonic atomizer (2) and transformed into a mist reaction liquid, which is then transported to the tubular furnace reactor (6). The mist reaction liquid reacts inside the quartz tube of the tubular furnace reactor (6) to generate carbon nanotubes. Finally, the carbon nanotubes are removed using an iron wire and tubular material stretching and collection system.

6. The method for preparing a carbon nanotube cylindrical structure according to claim 5, characterized in that: The mixed solution in step 1 is prepared according to the following mass percentages: carbon source 91.0-98.4%, catalyst 1.0-2.5%, promoter 0.6-1.5%, and water 0-5.0%.

7. The method for preparing a carbon nanotube cylindrical structure according to claim 5, characterized in that: In step 2, the flow rate of hydrogen is 400–800 sccm, and the flow rate of argon is 200–600 sccm.

8. The method for preparing a carbon nanotube cylindrical structure according to claim 5, characterized in that: In step 4, the temperature at which the carbon nanotubes are generated in the tubular furnace reactor (6) is 900~1200℃.

9. The method for preparing a carbon nanotube cylindrical structure according to claim 5, characterized in that: The carbon source is ethanol, acetone, ethanol, ethylene glycol, or n-hexane; the catalyst is a compound of iron, cobalt, or nickel; and the promoter is thiophene.

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