Chemical vapor deposition reactor, FCCVD reaction device and batch continuous preparation method of single-walled carbon nanotubes

Abstract

The invention relates to the technical field of preparation of single-walled carbon nanotubes, in particular to a chemical vapor deposition reactor, an FCCVD reaction device and a batch continuous preparation method of single-walled carbon nanotubes. By optimizing the structure of the reactor, the flow field in the reactor is further optimized, uniform distribution of gas is realized, and in-situ growth of catalyst particles and uniformity of the particle size are maintained. Results of the embodiment show that the reaction process is strengthened through optimization design of the reactor, batch continuous preparation of the single-walled carbon nanotubes can be achieved, the utilization efficiency of the catalyst is greatly improved, the yield of the unit catalyst is greatly improved, and the prepared SWCNT is high in quality.

Description

Technical Field

[0001] This invention relates to the field of single-walled carbon nanotube preparation technology, and in particular to a chemical vapor deposition reactor, an FCCVD reactor, and a method for the continuous batch preparation of single-walled carbon nanotubes. Background Technology

[0002] Single-walled carbon nanotubes (SWCNTs), as representatives of one-dimensional nanomaterials, have shown great application potential in fields such as electronic devices, energy storage, and composite materials due to their unique mechanical, electrical, and thermal properties. However, the high manufacturing cost of SWCNTs, currently limited by technological bottlenecks in mass production, restricts their large-scale application.

[0003] Methods for preparing single-walled carbon nanotubes (SNCNTs) include laser ablation, arc discharge, and chemical vapor deposition (CVD). CVD technology is favored due to its lower cost and ease of control. Among these, floating catalytic chemical vapor deposition (FCCVD) is considered the most typical method for the continuous production of high-yield, high-quality carbon nanotubes (CNTs). The FCCVD process involves feeding a catalyst precursor, carbon source, and carrier gas together into the high-temperature zone of a reactor, where they decompose to form floating nanoparticles and carbon atoms, ultimately catalyzing the growth of carbon nanotubes. This process can be continuous, including catalyst particle nucleation, SNCNT growth, and direct collection of SNCNTs. However, the most criticized aspect of FCCVD is its low yield (generally below 0.2 g CNTs / g catalyst) and low catalyst utilization, which limits its ability to achieve high yields and thus restricts its large-scale continuous production of single-walled carbon nanotubes. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a chemical vapor deposition reactor, an FCCVD reactor, and a method for the continuous batch preparation of single-walled carbon nanotubes. The FCCVD reactor provided by this invention enables the continuous batch preparation of single-walled carbon nanotubes, improves catalyst utilization, and produces high-quality SWCNTs.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a chemical vapor deposition reactor, comprising an inlet reaction tube, a straight-tube reaction tube, and an outlet reaction tube connected in sequence; the inlet reaction tube is an arc-shaped gradually expanding flow channel with an arc angle of 5-60°; the inner diameter of the starting end of the inlet reaction tube is 0.05-0.75 times the inner diameter of the ending end of the inlet reaction tube; the inner diameter of the ending end of the inlet reaction tube is the same as the inner diameter of the straight-tube reaction tube and the inner diameter of the starting end of the outlet reaction tube.

[0007] Preferably, the outlet section reaction tube is a straight-type gradually expanding flow channel or a curved-type gradually expanding flow channel.

[0008] Preferably, when the outlet section reaction tube is a straight, gradually expanding flow channel, the expansion angle of the outlet section reaction tube is 5-60°;

[0009] When the outlet section reaction tube is a curved, gradually expanding flow channel, the inner diameter of the tube end is 100-500 mm larger than the inner diameter of the straight section reaction tube.

[0010] Preferably, the length of the inlet section reaction tube is 250-4000 mm; the length of the straight section reaction tube is 2000-10000 mm.

[0011] Preferably, the length of the outlet section reaction tube is 200-2000 mm.

[0012] Preferably, the chemical vapor deposition reactor is made of graphite.

[0013] Preferably, the inner diameter of the straight section of the reaction tube is 300-1000 mm.

[0014] This invention provides an FCCVD reactor, including a feeding system, a chemical vapor deposition reactor as described above, a heating system, and a discharge collection system; the feeding system includes a preheater; the outlet of the preheater is connected to the inlet of the chemical vapor deposition reactor; the heating system is used to heat the chemical vapor deposition reactor; and the discharge collection system is connected to the outlet of the chemical vapor deposition reactor.

[0015] Preferably, the heating system is a medium-frequency induction heating system, and the heating system has a real-time monitoring and automatic adjustment function.

[0016] This invention provides a method for the batch and continuous preparation of single-walled carbon nanotubes using the FCCVD reactor described above, comprising the following steps: dissolving a co-catalyst and a catalyst precursor into a liquid carbon source to obtain reaction raw materials;

[0017] The reactants and carrier gas are mixed and then passed into a preheater for preheating to obtain a preheated mixture.

[0018] The preheated mixture is fed into a chemical vapor deposition reactor to grow single-walled carbon nanotubes. The resulting single-walled carbon nanotubes flow out of the chemical vapor deposition reactor and are collected by a discharge collection system to obtain single-walled carbon nanotubes.

[0019] This invention provides a chemical vapor deposition reactor, comprising an inlet section reaction tube, a straight section reaction tube, and an outlet section reaction tube connected in sequence; the inlet section reaction tube is an arc-shaped gradually expanding flow channel with an arc of 5-60°; the inner diameter of the end of the inlet section reaction tube is the same as the inner diameter of the straight section reaction tube and the inner diameter of the beginning of the outlet section reaction tube.

[0020] The present invention first provides a chemical vapor deposition reactor.

[0021] The inventors discovered that the low yield of single-walled carbon nanotubes prepared by traditional FCCVD is directly related to the reactor structure. Traditional FCCVD reactors are typically cylindrical reaction tubes (such as...). Figure 3 As shown in the diagram, when gas carrying carbon source and catalyst is injected at high speed into the cylindrical reactor, the gas velocity drops sharply due to the sudden increase in diameter (the gas carrying carbon source enters through a small tube, the diameter of which is significantly different from that of the reaction tube (generally 10-20 mm). Kinetic energy is converted into static pressure energy. The decrease in flow velocity is accompanied by an increase in static pressure, forming an adverse pressure gradient. Furthermore, due to the decrease in kinetic energy, when it is insufficient to overcome the adverse pressure gradient, the fluid decelerates to zero or even flows in reverse near the wall, thereby triggering boundary layer separation and forming a backflow zone, commonly known as a vortex. Eddy currents can easily cause backmixing of materials. Although backmixing increases residence time and carbon nanotube growth time, it also increases the probability of catalyst particle collision. Therefore, it is very easy for catalyst particles to grow and become deactivated or be encapsulated by carbon, resulting in a decrease in yield and a deterioration in the purity of SWCNTs. In addition, the eddy currents and backmixing caused by the sudden decrease in gas velocity, combined with the characteristics of the material itself, can cause the material to accumulate at the inlet, thereby affecting the continuous production of single-walled carbon nanotubes and, in severe cases, causing reactor blockage.

[0022] This invention optimizes the flow field inside the reactor to achieve uniform gas distribution, maintaining the in-situ growth and uniformity of catalyst particle size. Specifically, the reactor inlet is designed as a gradually expanding arc-shaped flow channel. The gradually expanding cross-section gradually reduces the fluid velocity, converting kinetic energy into static pressure energy, suppressing flow separation, reducing disordered eddies, promoting micro-mixing, and improving mixing efficiency. This results in uniform fluid distribution, promoting carbon nanotube growth. Furthermore, by suppressing eddy generation, the risk of material accumulation is also reduced, enabling continuous batch production of single-walled carbon nanotubes. In addition, the gradually expanding inlet design, by promoting uniform fluid distribution, also helps improve the uniformity of the temperature field within the reactor.

[0023] Compared to straight-line expanding channels, circular-arc expanding channels are more effective at suppressing flow separation, improving flow stability, maintaining boundary layer momentum, and reducing energy loss. This is because the circular-arc expanding channel gradually increases the expansion angle, making the channel wall more closely conform to the natural flow trajectory of the fluid. By effectively suppressing separation and reducing turbulence losses, the circular-arc design makes the fluid deceleration process smoother, more uniform, and more controllable. The fluid experiences less disturbance during expansion, and the energy conversion process is closer to an ideal reversible process.

[0024] The results of the embodiments show that the present invention strengthens the reaction process through optimized reactor design, greatly improves catalyst utilization efficiency, and significantly increases the yield per unit catalyst, thereby truly increasing the output.

[0025] Furthermore, single-walled carbon nanotubes possess strong viscosity. In the high-temperature zone, the thermophoretic force generated by the wall temperature being higher than the central fluid temperature causes the carbon nanotubes to aggregate towards the center of the reactor. At the low-temperature outlet, the same thermophoretic force causes the carbon nanotubes to aggregate towards the reactor wall due to the wall temperature being lower than the central fluid temperature. This often results in carbon nanotubes accumulating at the outlet, preventing continuous discharge and thus affecting continuous batch production. This invention further designs the reactor outlet as a gradually expanding flow channel, causing the fluid to decrease in velocity uniformly and promoting a more uniform temperature and concentration distribution in the outlet area, thereby reducing the risk of material accumulation at the outlet. Attached Figure Description

[0026] Figure 1 A schematic diagram of one structure of the chemical vapor deposition reactor provided by the present invention;

[0027] Figure 2 Another schematic diagram of the chemical vapor deposition reactor provided by the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of a traditional FCCVD reactor;

[0029] Figure 4 This is a schematic diagram of a FCCVD reactor; wherein, 1-feed system, 11-preheater, 12-input device, 13-gas tank, 14-raw material storage tank, 2-chemical vapor deposition reactor, 3-heating system, 4-discharge collection system;

[0030] Figure 5 The Raman spectrum of the single-walled carbon nanotubes prepared in Example 1;

[0031] Figure 6 The Raman spectrum of the single-walled carbon nanotubes prepared in Example 2;

[0032] Figure 7The Raman spectrum of the single-walled carbon nanotubes prepared in Example 4;

[0033] Figure 8 TEM image of the single-walled carbon nanotubes prepared in Example 6;

[0034] Figure 9 The Raman spectrum of the single-walled carbon nanotubes prepared in Example 6;

[0035] Figure 10 The Raman spectrum of the single-walled carbon nanotubes prepared in Example 7;

[0036] Figure 11 SEM image of the single-walled carbon nanotubes prepared in Example 9;

[0037] Figure 12 The Raman spectrum of the single-walled carbon nanotubes prepared in Example 9;

[0038] Figure 13 Raman spectrum of single-walled carbon nanotubes prepared in Example 10;

[0039] Figure 14 Raman spectrum of single-walled carbon nanotubes prepared in Example 11;

[0040] Figure 15 Raman spectrum of single-walled carbon nanotubes prepared in Example 12;

[0041] Figure 16 The Raman spectrum of the single-walled carbon nanotubes prepared for Comparative Example 2 is shown. Detailed Implementation

[0042] This invention provides a chemical vapor deposition reactor, comprising an inlet reaction tube, a straight-tube reaction tube, and an outlet reaction tube connected in sequence; the inlet reaction tube is an arc-shaped gradually expanding flow channel with an arc angle of 5-60°; the inner diameter of the starting end of the inlet reaction tube is 0.05-0.75 times the inner diameter of the ending end of the inlet reaction tube; the inner diameter of the ending end of the inlet reaction tube is the same as the inner diameter of the straight-tube reaction tube and the inner diameter of the starting end of the outlet reaction tube.

[0043] like Figure 1 As shown, the inlet section reaction tube is an arc-shaped, gradually expanding flow channel with an arc angle of 5-60° (i.e., θ1 is 5-60°). In specific embodiments, it can be 5°, 8°, 12°, 15°, 20°, 30°, 40°, 50°, or 60°, preferably 8-15°. This invention controls the arc angle of the inlet section reaction tube flow channel within the above range to prevent fluid flow separation and ensure uniform fluid flow.

[0044] In this invention, the inner diameter of the starting end of the inlet section reaction tube is 0.05-0.75 times the inner diameter of the ending end tube. In specific embodiments, it can be 0.1 times, 0.11 times, 0.15 times, 0.19 times, 0.2 times, 0.23 times, 0.25 times, 0.3 times, 0.35 times, 0.4 times, 0.45 times, 0.5 times, 0.55 times, 0.6 times, 0.65 times, 0.7 times, or 0.75 times. The inner diameter of the ending end of the inlet section reaction tube is the same as the inner diameter of the straight section reaction tube.

[0045] In this invention, the length of the inlet section reaction tube is preferably 250-4000 mm, and in specific embodiments it can be 250 mm, 450 mm, 500 mm, 1000 mm, 1500 mm, 2000 mm, 2500 mm, 3000 mm, 3500 mm, or 4000 mm. By designing the inlet section reaction tube as an arc-shaped, gradually expanding flow channel, this invention enables uniform fluid distribution, suppresses eddy current generation, ensures uniform catalyst nucleation, improves catalyst utilization, and reduces the risk of material accumulation, thereby guaranteeing continuous mass production of single-walled carbon nanotubes. In this invention, the wall thickness of the inlet section reaction tube is preferably 50-150 mm, and in specific embodiments it can be 50 mm, 75 mm, 100 mm, 120 mm, or 150 mm. The wall thickness of the inlet section reaction tube can be uniform or non-uniform; when non-uniform, the outer wall of the inlet section reaction tube is preferably cylindrical (equivalent to carving an arc-shaped curved flow channel from the middle of a cylinder).

[0046] In this invention, the inner diameter of the straight-tube reaction section is preferably 300-1000 mm, and in specific embodiments, it can be 300 mm, 450 mm, 600 mm, 750 mm, 800 mm, 900 mm, or 1000 mm. In this invention, the length of the straight-tube reaction section is preferably 2000-10000 mm, and in specific embodiments, it can be 2000 mm, 3000 mm, 4500 mm, 5000 mm, 6000 mm, 7000 mm, 8000 mm, 9000 mm, or 10000 mm. When the fluid develops from the expanded flow channel of the inlet section to a certain stage, it will form a stable laminar flow. At this time, using a straight-tube reaction tank is beneficial for the stable flow of the fluid. In this invention, the wall thickness of the straight-tube reaction section is preferably 50-150 mm, and in specific embodiments, it can be 50 mm, 75 mm, 100 mm, 120 mm, or 150 mm. In this invention, the wall thickness of the straight cylindrical reaction tube is preferably uniform.

[0047] In this invention, the outlet section reaction pipe is preferably a straight, gradually expanding flow channel (e.g., Figure 1 (as shown) or curved, gradually expanding flow channel (such as...) Figure 2(As shown). When it is a straight, gradually expanding flow channel, the expansion angle of the outlet section reaction tube is preferably 5-60° (e.g., Figure 1 As shown in θ3), in specific embodiments, the angle can be 5°, 8°, 12°, 15°, 20°, 30°, 40°, 50°, or 60°. When it is a curved gradually expanding flow channel, the curvature of the curved gradually expanding flow channel can be fixed or varied, as long as it satisfies the requirement of gradual expansion of the flow channel. For example, the curved gradually expanding flow channel can specifically be an arc-shaped gradually expanding flow channel (such as...). Figure 2 As shown, the flow channels can be categorized as fixed curvature, parabolic (with varying curvature, including the falling portion of the parabola), hyperbolic, or preferably circular arc-shaped gradually expanding flow channels. When the curved gradually expanding flow channel is a circular arc-shaped gradually expanding flow channel, the arc angle is preferably 5-60°, more preferably 8-15° (e.g., ...). Figure 2 As shown in θ2, in specific embodiments, it can be 5°, 8°, 12°, 15°, 20°, 30°, 40°, 50° or 60°.

[0048] In this invention, when the outlet section reaction tube is a curved, gradually expanding flow channel, the inner diameter of the tube end is preferably 100-500 mm larger than the inner diameter of the straight section reaction tube. In specific embodiments, it can be 100 mm, 200 mm, 300 mm, 400 mm, or 500 mm larger.

[0049] In this invention, the wall thickness of the outlet section reaction tube is either equal or non-equal, preferably non-equal (specifically, the outer wall of the outlet section can be cylindrical and the inner wall can be arc-shaped).

[0050] In this invention, the length of the outlet section reaction tube is preferably 200-2000 mm, and in specific embodiments it can be 200 mm, 500 mm, 800 mm, 1000 mm, 1200 mm, 1500 mm, 1800 mm, or 2000 mm. By designing the reactor outlet as an expanded flow channel, this invention can reduce the risk of material buildup at the outlet and improve the stability of continuous batch preparation of single-walled carbon nanotubes.

[0051] In this invention, the chemical vapor deposition reactor is preferably made of graphite. Compared to traditional reactors that use quartz or corundum ceramics, graphite has excellent heat storage and transfer characteristics, which is beneficial to the uniformity of temperature distribution within the reactor, and thus facilitates uniform catalyst nucleation, achieving efficient utilization of the catalyst.

[0052] Figure 3The structure of a traditional FCCVD reactor is shown, with both its inlet and outlet sections being cylindrical. This invention optimizes the reactor's inlet structure, stabilizing the internal flow field and ensuring uniform fluid and temperature distribution. This guarantees uniform catalyst nucleation and efficient catalyst utilization. Combined with the excellent heat storage and transfer characteristics of graphite, the uniformity of fluid concentration and temperature distribution within the reactor is further improved. Furthermore, a special discharge design ensures smooth material discharge, enabling the continuous batch production of single-walled carbon nanotubes.

[0053] like Figure 4 As shown, the present invention provides an FCCVD reactor, including a feeding system 1, the aforementioned chemical vapor deposition reactor 2, a heating system 3, and a discharge collection system 4; the feeding system includes a preheater; the outlet of the preheater is connected to the inlet of the chemical vapor deposition reactor; the heating system is used to heat the chemical vapor deposition reactor; the discharge collection system is connected to the outlet end of the chemical vapor deposition reactor.

[0054] The FCCVD reactor provided by this invention includes a feeding system 1. As an embodiment of this invention, the feeding system 1 includes a preheater 11, an input device 12, a gas tank 13, and a raw material storage tank 14. In this invention, the input device 12 can specifically be a transfer pump or other equipment capable of conveying the reaction raw materials; the input device 12 is used to convey the reaction raw materials (i.e., carbon source, catalyst precursor, and co-catalyst); the gas tank 13 is used to store carrier gas; the raw material storage tank 14 is used to store the reaction raw materials, i.e., a mixture of carbon source, co-catalyst, and catalyst precursor. In this invention, the outlet of the gas tank 13 is connected to the inlet of the preheater 11 via a first pipeline; the outlet of the raw material storage tank 14 is connected to the inlet of the input device 12, and the outlet of the input device 12 is connected to the pipeline between the gas tank 13 and the preheater 11.

[0055] The FCCVD reactor provided by this invention includes a chemical vapor deposition reactor 2, the structure of which has been described above and will not be repeated here. In this invention, the chemical vapor deposition reactor 2 provides a reaction site for the synthesis of single-walled carbon nanotubes. In this invention, the chemical vapor deposition reactor 2 is placed vertically to the ground, with the inlet located at the top and the outlet at the bottom. In this invention, the outlet of the preheater 11 is connected to the inlet of the reactor 2 via a second pipe. The inner diameter of the second pipe is preferably 8-50 mm, and the end of the pipe extends into the reactor 2 at a position of 0-200 mm. In specific embodiments, this can be 0 mm, 50 mm, 80 mm, 100 mm, 150 mm, 180 mm, or 200 mm. In this invention, the distance between the end of the second pipe and the straight section of the reaction tube is at least 50 mm, more preferably at least 80 mm.

[0056] The FCCVD reactor provided by this invention includes a heating system 3; the heating system 3 is used to heat the reactor 2. In this invention, the heating system 3 is preferably a medium-frequency induction heating system. In this invention, the oscillation frequency of the medium-frequency induction heating system is adjustable, preferably in the range of 1-20KHz, and the output power is preferably 300-600kW. This invention uses medium-frequency induction heating to magnetically induction heat the reactor, which can achieve rapid temperature rise.

[0057] As one embodiment of the present invention, the heating system 3 includes a power control unit, an induction coil, an insulation layer, a water cooling device, and a sealed furnace shell. The present invention does not impose any special limitations on the specific structure of the heating system, as this is well known in the art.

[0058] In a preferred embodiment of the present invention, the heating system 3 is equipped with a real-time monitoring and automatic adjustment function. By employing a real-time monitoring and automatic adjustment system, the present invention can monitor the reactor temperature field in real time and automatically adjust the induction heating power through feedback control to maintain the set temperature distribution. The present invention does not impose special requirements on the structure of the heating system with the real-time monitoring and automatic adjustment function; any heating system with this structure known in the art is acceptable.

[0059] The FCCVD reactor provided by this invention includes a discharge collection system 4; the discharge collection system 4 is used to collect single-walled carbon nanotubes. In this invention, the discharge collection system is located at the lower end of the chemical vapor deposition reactor 2 and is connected to the discharge port of the chemical vapor deposition reactor 2. Specifically, the discharge system can be a receiving tank.

[0060] This invention provides a method for the batch and continuous preparation of single-walled carbon nanotubes using the above-mentioned FCCVD reaction device, comprising the following steps: dissolving a co-catalyst and a catalyst precursor into a liquid carbon source to obtain a reaction raw material; mixing the reaction raw material with a carrier gas and then passing it into a preheater for preheating to obtain a preheated mixture;

[0061] The preheated mixture is fed into a chemical vapor deposition reactor to grow single-walled carbon nanotubes. The resulting single-walled carbon nanotubes flow out of the chemical vapor deposition reactor and are collected by a discharge collection system to obtain single-walled carbon nanotubes.

[0062] Unless otherwise specified, all raw materials used in this invention are commercially available products well known in the art.

[0063] This invention dissolves a co-catalyst and a catalyst precursor into a liquid carbon source to obtain reaction raw materials.

[0064] In this invention, the liquid carbon source preferably includes one or more of ethanol, n-butanol, toluene, benzyl alcohol, xylene, and cyclohexane.

[0065] This invention does not have specific requirements regarding the type of catalyst precursor; any catalyst precursor well-known in the art for preparing single-walled carbon nanotubes is acceptable, generally a precursor of a Group VIII transition metal, more preferably an iron-containing compound; the iron-containing compound can be ferrocene, iron carbonyl, iron acetate, iron ethoxide, or iron citrate. The mass of the catalyst precursor is preferably 0.5% to 4.5% of the mass of the reactants, and in specific embodiments, it can be 0.5%, 1%, 2%, 2.5%, 3%, 4%, or 4.5%.

[0066] In this invention, the co-catalyst is preferably elemental sulfur or a sulfur-containing compound, and the sulfur-containing compound preferably includes one or more of thiophene, carbon disulfide, and hydrogen sulfide; the mass of the co-catalyst is preferably 0.5% to 4.5% of the total mass of the reaction raw materials, and in specific embodiments it can be 0.5%, 1%, 1.5%, 2%, 3%, 4%, or 4.5%. In this invention, the co-catalyst helps stabilize the particle size of the catalyst, improve the growth efficiency of carbon nanotubes, and increase the yield.

[0067] In this invention, the obtained reaction raw materials are preferably placed in the raw material storage tank 14.

[0068] The reactants are obtained by mixing them with a carrier gas and then passing the mixture into a preheater for preheating to obtain a preheated mixture.

[0069] In this invention, the carrier gas is preferably one or more of Ar, N2, H2, and He. Specifically, in embodiments of this invention, it is a mixture of argon and hydrogen in a 1:1 volume ratio. The flow rate of the carrier gas is preferably 200-2000 L / min, and in specific embodiments, it can be 200 L / min, 500 L / min, 800 L / min, 1000 L / min, 1300 L / min, 1500 L / min, or 2000 L / min. In this invention, the function of the carrier gas is to maintain a slight positive pressure and prevent oxygen from entering the device.

[0070] In this invention, the flow rate of the reaction raw materials is preferably 5 to 100 mL / min, and in specific embodiments it can be 10 mL / min, 25 mL / min, 30 mL / min, 50 mL / min, 70 mL / min, 80 mL / min or 100 mL / min.

[0071] In this invention, the preheating temperature is preferably 200-600℃, and in specific embodiments it can be 200℃, 300℃, 400℃, 500℃, or 600℃. This invention, through preheating, allows the fluid to reach a more uniform temperature more quickly, which is beneficial for the reaction.

[0072] After obtaining the preheated mixture, the present invention feeds the preheated mixture into a chemical vapor deposition reactor to grow single-walled carbon nanotubes. The formed single-walled carbon nanotubes flow out of the chemical vapor deposition reactor and are collected in a discharge collection system to obtain single-walled carbon nanotubes.

[0073] The present invention preferably first purges the entire device with Ar gas to remove the air inside the device, and then starts the heating system to heat the system.

[0074] In this invention, the heating temperature of the chemical vapor deposition reactor is preferably 1100-1300℃, and in specific embodiments it can be 1100℃, 1200℃, 1250℃ or 1300℃. After the reactants enter the chemical vapor deposition reactor, the catalyst precursor is in situ generated into catalyst particles (iron nanoparticles in the embodiments), and at the same time, the carbon source is decomposed into carbon atoms, which undergo adsorption, deposition, diffusion precipitation and growth on the catalyst in situ, and single-walled carbon nanotubes are grown in situ on the catalyst particles.

[0075] After growth, under the influence of airflow and gravity, the single-walled carbon nanotubes are eventually collected in the collection device at the bottom of the reactor to obtain single-walled carbon nanotubes.

[0076] The single-walled carbon nanotubes prepared by this invention have the characteristics of good crystallinity, large aspect ratio, high purity and few impurities, and represent an excellent method for producing single-walled carbon nanotubes.

[0077] The following detailed description, in conjunction with embodiments, of the chemical vapor deposition reactor, FCCVD reaction apparatus, and batch continuous preparation method of single-walled carbon nanotubes provided by the present invention, should not be construed as limiting the scope of protection of the present invention.

[0078] Example 1

[0079] The chemical vapor deposition reactor consists of three reaction tubes, all made of graphite. The first part is an arc-shaped, gradually expanding flow channel with an arc of 5°, an inner diameter of 100 mm at the beginning, an inner diameter of 400 mm at the end, a wall thickness of 50 mm, and a length of 1000 mm. The second part is a straight cylindrical reaction tube with an inner diameter of 400 mm, a wall thickness of 50 mm, and a length of 3000 mm. The third part is an arc-shaped, gradually expanding flow channel with an arc of 12°, a thickness of 50 mm, a length of 500 mm, and an inner diameter of 600 mm at the end.

[0080] The catalyst precursor used is ferrocene, the liquid carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0081] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0082] Turn on the delivery pump and mix the liquid carbon source with the carrier gas at a flow rate of 25 mL / min. Then send the mixture into the preheater for preheating. The carrier gas flow rate is 500 L / min. Preheat to 300°C to obtain a preheated mixture.

[0083] The preheated mixture was fed into a reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor) for single-walled carbon nanotube growth at 1150℃. After exiting the expanded angle channel, the mixture was collected in a collection tank to obtain single-walled carbon nanotubes. The final yield was 138 g / h, equivalent to 9.2 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 77%, and the Raman GD ratio was 90 (e.g., ...). Figure 5 ).

[0084] Note: This invention obtains the mass of catalyst entering the reactor per unit time based on the concentration of catalyst in the reaction feedstock, and then obtains the carbon yield per unit catalyst by dividing the mass of the collected product by the mass of the catalyst.

[0085] Example 2

[0086] The chemical vapor deposition reactor consists of three reaction tubes, all made of graphite. The first part is an arc-shaped, gradually expanding flow channel with an arc of 8°, an inner diameter of 100 mm at the beginning, an inner diameter of 400 mm at the end, a wall thickness of 50 mm, and a length of 1000 mm. The second part is a straight cylindrical reaction tube with an inner diameter of 400 mm, a wall thickness of 50 mm, and a length of 3000 mm. The third part is an arc-shaped, gradually expanding flow channel with an arc of 12°, a thickness of 50 mm, a length of 500 mm, and an inner diameter of 600 mm at the end.

[0087] The catalyst precursor used is ferrocene, the liquid carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0088] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0089] Turn on the delivery pump and mix the liquid carbon source with the carrier gas at a flow rate of 25 mL / min. Then send the mixture into the preheater for preheating. The carrier gas flow rate is 500 L / min. Preheat to 300°C to obtain a preheated mixture.

[0090] The preheated mixture was fed into a reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor) for single-walled carbon nanotube growth at 1150 °C. After exiting the expanded angle channel, the mixture was collected in a collection tank to obtain single-walled carbon nanotubes. The final yield was 142 g / h, equivalent to 9.5 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 76% and the Raman GD ratio was 95 (see...). Figure 6 ).

[0091] Example 3

[0092] The chemical vapor deposition reactor consists of three reaction tubes, all made of graphite. The first part is an arc-shaped, gradually expanding flow channel with an arc radius of 12°. The inner diameter at the beginning of the tube is 100 mm, the inner diameter at the end is 400 mm, the wall thickness is 50 mm, and the length is 1000 mm. The second part is a straight cylindrical reaction tube with an inner diameter of 400 mm, a wall thickness of 50 mm, and a length of 3000 mm. The third part is an arc-shaped, gradually expanding flow channel with an arc radius of 12°, a thickness of 50 mm, a length of 500 mm, and an inner diameter at the end of the tube of 600 mm.

[0093] The catalyst precursor used is ferrocene, the liquid carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0094] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0095] Turn on the delivery pump and mix the liquid carbon source with the carrier gas at a flow rate of 25 mL / min. Then send the mixture into the preheater for preheating. The carrier gas flow rate is 500 L / min. Preheat to 300°C to obtain a preheated mixture.

[0096] The preheated mixture was fed into a reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor) to grow single-walled carbon nanotubes at 1150 °C. After exiting the expansion angle channel, the mixture was collected in a collection tank to obtain single-walled carbon nanotubes. The final yield was 140 g / h, equivalent to 9.3 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 78% and the Raman GD ratio was 98.

[0097] Example 4

[0098] The chemical vapor deposition reactor consists of three reaction tubes, all made of graphite. The first part is an arc-shaped, gradually expanding flow channel with an arc of 18°, an inner diameter of 100 mm at the beginning, an inner diameter of 400 mm at the end, a wall thickness of 50 mm, and a length of 1000 mm. The second part is a straight cylindrical reaction tube with an inner diameter of 400 mm, a wall thickness of 50 mm, and a length of 3000 mm. The third part is an arc-shaped, gradually expanding flow channel with an arc of 12°, a thickness of 50 mm, a length of 500 mm, and an inner diameter of 600 mm at the end.

[0099] The catalyst precursor used is ferrocene, the carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0100] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0101] Turn on the delivery pump and mix the reactants with the carrier gas at a flow rate of 25 mL / min. The mixture is then fed into the preheater for preheating. The carrier gas flow rate is 500 L / min. The mixture is preheated to 300°C to obtain a preheated mixture.

[0102] The preheated mixture was fed into the reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor), and single-walled carbon nanotubes were grown at 1150 °C. After passing through the expansion angle channel outlet, the mixture entered the collection tank for collection, yielding single-walled carbon nanotubes. The final yield was 134 g / h, equivalent to 8.9 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 79%, and the Raman GD ratio was 89 (see...). Figure 7 ).

[0103] Example 5

[0104] The chemical vapor deposition reactor consists of three reaction tubes, all made of graphite. The first part is an arc-shaped, gradually expanding flow channel with an arc radius of 22°. The inner diameter at the beginning of the tube is 100 mm, the inner diameter at the end is 400 mm, the wall thickness is 50 mm, and the length is 1000 mm. The second part is a straight cylindrical reaction tube with an inner diameter of 400 mm, a wall thickness of 50 mm, and a length of 3000 mm. The third part is an arc-shaped, gradually expanding flow channel with an arc radius of 12°, a thickness of 50 mm, a length of 500 mm, and an inner diameter at the end of the tube of 600 mm.

[0105] The catalyst precursor used is ferrocene, the liquid carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0106] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0107] Turn on the delivery pump and mix the liquid carbon source with the carrier gas at a flow rate of 25 mL / min. Then send the mixture into the preheater for preheating. The carrier gas flow rate is 500 L / min. Preheat to 300°C to obtain a preheated mixture.

[0108] The preheated mixture was fed into a reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor) to grow single-walled carbon nanotubes at 1150 °C. After exiting the expansion angle channel, the mixture was collected in a collection tank to obtain single-walled carbon nanotubes. The final yield was 130 g / h, equivalent to 8.7 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 73% and the Raman GD ratio was 88.

[0109] Example 6

[0110] The chemical vapor deposition reactor consists of three reaction tubes, all made of graphite. The first part is an arc-shaped, gradually expanding flow channel with an arc of 36°, an inner diameter of 100 mm at the beginning, an inner diameter of 400 mm at the end, a thickness of 50 mm, and a length of 500 mm. The second part is a straight cylindrical reaction tube with an inner diameter of 400 mm, a wall thickness of 50 mm, and a length of 3000 mm. The third part is an arc-shaped, gradually expanding flow channel with an arc of 12°, a thickness of 50 mm, a length of 500 mm, and an inner diameter of 600 mm at the end.

[0111] The catalyst precursor used is ferrocene, the carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0112] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0113] Turn on the delivery pump and mix the reactants with the carrier gas at a flow rate of 25 mL / min. The mixture is then fed into the preheater for preheating. The auxiliary gas flow rate is 500 L / min. The mixture is preheated to 300°C to obtain a preheated mixture.

[0114] The preheated mixture was fed into a reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor). Single-walled carbon nanotubes were grown at 1150℃. After exiting the expansion channel, the mixture was collected in a collection tank to obtain single-walled carbon nanotubes. The final yield was 120 g / h, equivalent to 8 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 85%. Raman spectroscopy revealed a prominent RBM peak, indicating the presence of single-walled carbon nanotubes. The D peak was very small, while the G peak was very sharp, resulting in a Raman GD ratio of 103 (see...). Figure 9 TEM characterization of the prepared samples revealed clearly visible single-walled carbon nanotubes (see...). Figure 8 ).

[0115] Example 7

[0116] The chemical vapor deposition reactor consists of three reaction tubes, all made of graphite. The first part is an arc-shaped, gradually expanding flow channel with an arc of 45°, an inner diameter of 100 mm at the beginning, an inner diameter of 400 mm at the end, a thickness of 50 mm, and a length of 400 mm. The second part is a straight cylindrical reaction tube with an inner diameter of 400 mm, a wall thickness of 50 mm, and a length of 3000 mm. The third part is an arc-shaped, gradually expanding flow channel with an arc of 12°, a thickness of 50 mm, a length of 500 mm, and an inner diameter of 600 mm at the end.

[0117] The catalyst precursor used is ferrocene, the carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0118] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0119] Turn on the delivery pump and mix the reactants with the carrier gas at a flow rate of 25 mL / min. The mixture is then fed into the preheater for preheating. The auxiliary gas flow rate is 500 L / min. The mixture is preheated to 300°C to obtain a preheated mixture.

[0120] The preheated mixture was fed into a reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor). Single-walled carbon nanotubes were grown at 1150℃. After exiting the expanded angle channel, the mixture was collected in a collection tank to obtain single-walled carbon nanotubes. The final yield was 115 g / h, equivalent to 7.6 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 79%. Raman spectroscopy characterization revealed a Raman GD ratio of 113 (e.g., ...). Figure 10 ).

[0121] Example 8

[0122] The chemical vapor deposition reactor consists of three reaction tubes, all made of graphite. The first part is an arc-shaped, gradually expanding flow channel with an arc of 60°, an inner diameter of 100mm at the beginning, an inner diameter of 400mm at the end, a thickness of 50mm, and a length of 300mm. The second part is a straight cylindrical reaction tube with an inner diameter of 400mm, a wall thickness of 50mm, and a length of 3000mm. The third part is an arc-shaped, gradually expanding flow channel with an arc of 12°, a thickness of 50mm, a length of 500mm, and an inner diameter of 600mm at the end.

[0123] The catalyst precursor used is ferrocene, the carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0124] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0125] Turn on the delivery pump and mix the reactants with the carrier gas at a flow rate of 25 mL / min. The mixture is then fed into the preheater for preheating. The auxiliary gas flow rate is 500 L / min. The mixture is preheated to 300°C to obtain a preheated mixture.

[0126] The preheated mixture was fed into the reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor), and single-walled carbon nanotubes were grown at 1150 °C. After the expansion angle flow channel outlet, the mixture entered the collection tank for collection, and single-walled carbon nanotubes were obtained. The final yield was 107 g / h, which is equivalent to 7.1 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 79%, and Raman spectroscopy characterization showed that the Raman GD ratio was 91.

[0127] Example 9

[0128] The chemical vapor deposition reactor consists of three reaction tubes, all made of graphite. The first part is an arc-shaped, gradually expanding flow channel with an arc of 8°, an inner diameter of 75 mm at the beginning, an inner diameter of 400 mm at the end, a wall thickness of 50 mm, and a length of 2000 mm. The second part is a straight cylindrical reaction tube with an inner diameter of 400 mm, a wall thickness of 50 mm, and a length of 3000 mm. The third part is an arc-shaped, gradually expanding flow channel with an arc of 12°, a thickness of 50 mm, a length of 500 mm, and an inner diameter of 600 mm at the end.

[0129] The catalyst precursor used is ferrocene, the carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0130] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0131] Turn on the delivery pump and mix the reactants with the carrier gas at a flow rate of 25 mL / min. The mixture is then fed into the preheater for preheating. The flow rate of the carrier gas is 500 L / min. The mixture is preheated to 300°C to obtain a preheated mixture.

[0132] The preheated mixture was fed into a reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor). Single-walled carbon nanotubes were grown at 1150 °C. After exiting the expanded angle channel, the mixture was collected in a collection tank to obtain single-walled carbon nanotubes. The final yield was 150 g / h, equivalent to 10 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 79%. Raman spectroscopy revealed a prominent RBM peak, indicating the presence of single-walled carbon nanotubes. The D peak was small, while the G peak was sharp, resulting in a Raman GD ratio of 85 (see...). Figure 12 SEM characterization of the prepared samples revealed clearly visible single-walled carbon nanotubes (see...). Figure 11 ).

[0133] Example 10

[0134] The chemical vapor deposition reactor consists of three reaction tubes, all made of graphite. The first part is an arc-shaped, gradually expanding flow channel with an arc of 8°, an inner diameter of 75 mm at the beginning, an inner diameter of 400 mm at the end, a wall thickness of 50 mm, and a length of 3000 mm. The second part is a straight cylindrical reaction tube with an inner diameter of 400 mm, a wall thickness of 50 mm, and a length of 3000 mm. The third part is an arc-shaped, gradually expanding flow channel with an arc of 12°, a thickness of 50 mm, a length of 500 mm, and an inner diameter of 600 mm at the end.

[0135] The catalyst precursor used is ferrocene, the carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0136] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0137] Turn on the delivery pump and mix the reactants with the carrier gas at a flow rate of 25 mL / min. The mixture is then fed into the preheater for preheating. The flow rate of the carrier gas is 500 L / min. The mixture is preheated to 300°C to obtain a preheated mixture.

[0138] The preheated mixture was fed into a reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor), and single-walled carbon nanotubes were grown at 1150 °C. After exiting the expanded angle channel, the mixture was collected in a collection tank to obtain single-walled carbon nanotubes. The final yield was 132 g / h, equivalent to 8.8 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 78%, and the Raman GD ratio was 92 (see...). Figure 13 ).

[0139] Example 11

[0140] The chemical vapor deposition reactor consists of three reaction tubes, all made of graphite. The first part is an arc-shaped, gradually expanding flow channel with an arc of 8°, an inner diameter of 75 mm at the beginning, an inner diameter of 700 mm at the end, a wall thickness of 50 mm, and a length of 1000 mm. The second part is a straight cylindrical reaction tube with an inner diameter of 700 mm, a wall thickness of 50 mm, and a length of 3000 mm. The third part is an arc-shaped, gradually expanding flow channel with an arc of 12°, a thickness of 50 mm, a length of 500 mm, and an inner diameter of 1000 mm at the end.

[0141] The catalyst precursor used is ferrocene, the liquid carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0142] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 550kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0143] Turn on the delivery pump and mix the liquid carbon source with the carrier gas at a flow rate of 50 mL / min. The mixture is then introduced into the preheater for preheating. The carrier gas flow rate is 1000 L / min. The mixture is preheated to 300°C to obtain a preheated mixture.

[0144] The preheated mixture was fed into the reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor), and single-walled carbon nanotubes were grown at 1150 °C. After exiting the expanded angle channel, the mixture was collected in a collection tank to obtain single-walled carbon nanotubes. The final yield was 234 g / h, equivalent to 7.8 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 79%, and the Raman GD ratio was 105 (see...). Figure 14 ).

[0145] Example 12

[0146] The chemical vapor deposition reactor consists of three reaction tubes, all made of graphite. The first part is an arc-shaped, gradually expanding flow channel with an arc of 8°. The inner diameter at the beginning of the tube is 100 mm, the inner diameter at the end is 400 mm, the wall thickness is 50 mm, and the length is 1000 mm. The second part is a straight cylindrical reaction tube with an inner diameter of 400 mm, a wall thickness of 50 mm, and a length of 3000 mm. The third part is a straight, gradually expanding flow channel with an expansion angle of 12°, a thickness of 50 mm, and a length of 500 mm.

[0147] The catalyst precursor used is ferrocene, the liquid carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0148] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0149] Turn on the delivery pump and mix the liquid carbon source with the carrier gas at a flow rate of 25 mL / min. The mixture is then introduced into the preheater for preheating. The carrier gas flow rate is 500 L / min. The mixture is preheated to 300°C to obtain a preheated mixture.

[0150] The preheated mixture was fed into the reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor), and single-walled carbon nanotubes were grown at 1150℃. After exiting the expanded angle channel, the mixture was collected in a collection tank to obtain single-walled carbon nanotubes. The final yield was 109 g / h, equivalent to 7.3 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 75% and the Raman GD ratio was 85 (see...). Figure 15 ).

[0151] Comparative Example 1

[0152] The only difference from Example 2 is that the inlet section of the reaction tube is a straight, gradually expanding flow channel, as detailed below:

[0153] Single-walled carbon nanotubes were prepared using a linear, gradually expanding flow channel reactor with an inlet section, also employing medium-frequency induction heating. The expansion angle was 8°, the wall thickness was 50 mm, the outer diameter at the tube end was 500 mm, and the length was 1000 mm. The second part was a straight cylindrical reaction tube with an inner diameter of 400 mm, a wall thickness of 50 mm, and a length of 3000 mm. The third part was an arc-shaped, gradually expanding flow channel with an arc radius θ of 12°, a thickness of 50 mm, a length of 500 mm, and an inner diameter at the tube end of 600 mm.

[0154] The catalyst precursor used is ferrocene, the carbon source is ethanol, and the co-catalyst is thiophene. The mass ratio of ethanol, thiophene and ferrocene is 96:3:1. The carrier gas is a mixture of argon and hydrogen with a volume ratio of 1:1. The catalyst precursor and co-catalyst are dissolved in the carbon source to obtain the reaction raw materials, which are then placed in a raw material storage tank.

[0155] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0156] Turn on the delivery pump and mix the reactants with the carrier gas at a flow rate of 25 mL / min. The mixture is then fed into the preheater for preheating. The flow rate of the carrier gas is 500 L / min. The mixture is preheated to 300°C to obtain a preheated mixture.

[0157] The preheated mixture was fed into a reactor (the inner diameter of the pipe between the preheater and the reactor was 16 mm, and the end of the pipe extended 100 mm into the reactor) to grow single-walled carbon nanotubes at 1150℃. The grown carbon nanotubes were collected in a collection tank from the outlet. During the collection process, it was found that the material accumulated at the outlet, causing difficulties in discharging. The final product yield was 89 g / h, which is equivalent to 5.9 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed that the product purity was 63% and the Raman GD ratio was 65.

[0158] Comparative Example 2

[0159] The difference from Example 2 is that a conventional cylindrical reactor was used to prepare single-walled carbon nanotubes, also employing medium-frequency induction heating. The tubes had an inner diameter of 400 mm, a wall thickness of 50 mm, and a length of 4500 mm. The catalyst precursor used was ferrocene, the carbon source was ethanol, and the co-catalyst was thiophene, with a mass ratio of ethanol, thiophene, and ferrocene of 96:3:1. The carrier gas was a mixture of argon and hydrogen in a volume ratio of 1:1. The catalyst precursor and co-catalyst were dissolved in the carbon source to obtain the reaction raw materials, which were then placed in a raw material storage tank.

[0160] First, the entire reaction apparatus is purged and cleaned with Ar gas to remove the air inside the apparatus. Then, the medium-frequency induction heating system is started to heat the system. The output power of the medium-frequency induction heating power supply is adjusted to 450kW, the oscillation frequency is 2.5kHz, and the temperature inside the graphite furnace tube is controlled at 1150℃.

[0161] Turn on the delivery pump and mix the reactants with the carrier gas at a flow rate of 25 mL / min. The mixture is then fed into the preheater for preheating. The flow rate of the carrier gas is 500 L / min. The mixture is preheated to 300°C to obtain a preheated mixture.

[0162] The preheated mixture was fed into the reactor for single-walled carbon nanotube growth at 1150℃. The grown carbon nanotubes were then collected in a collection tank from the outlet. During collection, material accumulation at the outlet caused difficulties in discharging. The final product yield was 35 g / h, equivalent to 2.3 g carbon nanotubes / g catalyst. Thermogravimetric analysis showed a product purity of 53% and a Raman GD ratio of 45 (see...). Figure 16 ).

[0163] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A chemical vapor deposition reactor, characterized in that, It includes an inlet section reaction tube, a straight section reaction tube, and an outlet section reaction tube connected in sequence; the inlet section reaction tube is an arc-shaped gradually expanding flow channel with an arc of 5-60°; the inner diameter of the starting end of the inlet section reaction tube is 0.05-0.75 times the inner diameter of the ending end of the inlet section reaction tube; the inner diameter of the ending end of the inlet section reaction tube is the same as the inner diameter of the straight section reaction tube and the inner diameter of the starting end of the outlet section reaction tube.

2. The chemical vapor deposition reactor according to claim 1, characterized in that, The outlet section reaction tube is a straight, gradually expanding flow channel or a curved, gradually expanding flow channel.

3. The chemical vapor deposition reactor according to claim 2, characterized in that, When the outlet section reaction tube is a straight, gradually expanding flow channel, the expansion angle of the outlet section reaction tube is 5-60°. When the outlet section reaction tube is a curved, gradually expanding flow channel, the inner diameter of the tube end is 100-500 mm larger than the inner diameter of the straight section reaction tube.

4. The chemical vapor deposition reactor according to claim 1 or 2, characterized in that, The length of the inlet section reaction tube is 250-4000mm; the length of the straight section reaction tube is 2000-10000mm.

5. The chemical vapor deposition reactor according to claim 1, 2, or 3, characterized in that, The length of the outlet section reaction tube is 200-2000 mm.

6. The chemical vapor deposition reactor according to claim 1 or 2, characterized in that, The chemical vapor deposition reactor is made of graphite.

7. The chemical vapor deposition reactor according to claim 1 or 2, characterized in that, The inner diameter of the straight-tube reaction section is 300-1000mm.

8. An FCCVD reaction apparatus, characterized in that, The device includes a feeding system, a chemical vapor deposition reactor as described in any one of claims 1-7, a heating system, and a discharge collection system; the feeding system includes a preheater; the outlet of the preheater is connected to the inlet of the chemical vapor deposition reactor; the heating system is used to heat the chemical vapor deposition reactor; and the discharge collection system is connected to the outlet end of the chemical vapor deposition reactor.

9. The FCCVD reactor according to claim 8, characterized in that, The heating system is a medium-frequency induction heating system, which has a real-time monitoring and automatic adjustment function.

10. A method for batch and continuous preparation of single-walled carbon nanotubes using the FCCVD reactor according to any one of claims 8-9, comprising the following steps: The co-catalyst and catalyst precursor are dissolved in a liquid carbon source to obtain the reaction raw materials; The reactants and carrier gas are mixed and then passed into a preheater for preheating to obtain a preheated mixture. The preheated mixture is fed into a chemical vapor deposition reactor to grow single-walled carbon nanotubes. The resulting single-walled carbon nanotubes flow out of the chemical vapor deposition reactor and are collected by a discharge collection system to obtain single-walled carbon nanotubes.

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