Continuous preparation device and method for high-purity single-walled carbon nanotubes

Abstract

The present invention provides a continuous preparation device and method for high-purity single-walled carbon nanotubes. A continuous preparation device for high-purity single-walled carbon nanotubes, the structure of the device includes a plasma arc furnace, a growth chamber, and a discharge chamber arranged in sequence; the structure of the plasma arc furnace includes a hollow graphite cathode, a graphite crucible as the anode, and a furnace chamber. Adopting the structure where the arc evaporation chamber and the growth chamber are separated and share the crucible, heat is transferred to the growth chamber through the molten metal liquid surface in the crucible, which can effectively reduce the amount of catalyst evaporated by the plasma arc furnace entering the growth chamber, and at the same time utilize the high-temperature heat source in the furnace to provide energy for subsequent reactions. Moreover, by adjusting the channel size, the amount of catalyst can be further finely controlled, and even directly use the heat in the growth chamber to slowly evaporate the bottom electrode catalyst, significantly reducing the amount of ineffective catalyst and improving the purity of the final single-walled carbon nanotube product.

Description

Technical Field

[0001] The present invention relates to the technical field of nanocarbon materials, and specifically provides a continuous preparation device and method for high-purity single-walled carbon nanotubes. Background Art

[0002] Single-walled carbon nanotubes are one-dimensional tubular nanostructures composed of all carbon-carbon covalent bonds. Thanks to their perfect structure, they exhibit excellent mechanical, electrical, and thermal properties, with performance advantages that are incomparable to conventional multi-walled carbon nanotubes, making them a current research and application hotspot. Due to the characteristics of their own structure, high crystallinity and large surface curvature, single-walled carbon nanotubes require a higher reaction barrier to grow, and the required preparation conditions are more demanding.

[0003] Currently, the main preparation methods for single-walled carbon nanotubes include: arc ablation method, laser method, chemical vapor deposition method, plasma method, etc. Although the chemical vapor deposition method has achieved great success in the field of preparing multi-walled carbon nanotubes and has realized the production of tens of thousands of tons, the preparation of single-walled carbon nanotubes by this method still remains at the laboratory stage, and more efficient preparation technologies still require high-temperature reaction technical routes.

[0004] Chinese invention patent CN201010234322.4 discloses a preparation method for diameter-controllable single-walled carbon nanotubes based on the arc method. The preparation process: a transition metal catalyst and 99.99% graphite powder are fully mixed in proportion to obtain an anode rod, and a pure graphite rod is used as the cathode for arc discharge. By controlling the discharge current, discharge voltage, and atmosphere pressure between the anode and cathode, diameter-controllable single-walled carbon nanotubes can be prepared. K. S. Kim et al. reported a method for preparing single-walled carbon nanotubes by the plasma method, in which the carbon source and catalyst are directly sprayed out through an Ar-H2 plasma torch, and single-walled carbon nanotube products are obtained at the cooling end (K. S. Kim, C. T. Kingston, D. Ruth, M. Barnes, B. Simard, Synthesisof high quality single-walled carbon nanotubes with purity enhancement anddiameter control by liquid precursor Ar-H2 plasma spraying, ChemicalEngineering Journal 250 (2014) 331-341).

[0005] Chinese invention patent CN 201910533219.0 is a method for preparing single-walled carbon nanotubes publicly disclosed by the applicant at an early stage. It uses a plasma arc to evaporate a catalyst metal to prepare a catalyst, while introducing a carbon source gas. The high-temperature plasma simultaneously realizes the high-temperature evaporation of the metal to prepare the catalyst and the cracking of the organic carbon source, directly preparing single-walled carbon nanotubes. However, the biggest drawback of this method is that the evaporation amount of the catalyst cannot be controlled, and its evaporation amount is much larger than that required for the growth of single-walled carbon nanotubes, resulting in a large amount of unutilized catalyst particles remaining mixed in the product. At the same time, the plasma arc is very sensitive to the atmosphere, and the carbon source gas and carrier gas of the auxiliary components cause the arc to be unstable, severely restricting the continuous progress of the reaction. Chinese invention patent CN202111322714.0 can partially solve the current problem through the attempt to isolate the catalyst evaporation chamber and the growth chamber, but the simple division method will cause the catalyst to aggregate and grow during transportation and become ineffective, and at the same time, it will also reduce the thermal energy utilization rate, resulting in a decrease in the yield and an increase in the preparation cost. There are still great challenges in the continuous batch preparation of single-walled carbon nanotubes. Summary of the Invention

[0006] In view of the above problems, the present invention provides a continuous preparation device and method for high-purity single-walled carbon nanotubes;

[0007] On the one hand, the present invention provides the following technical solutions:

[0008] A continuous preparation device for high-purity single-walled carbon nanotubes, the structure of the device includes a plasma arc furnace, a growth chamber, and a discharge chamber arranged in sequence;

[0009] The structure of the plasma arc furnace includes a hollow graphite cathode, a graphite crucible as the anode, and a furnace chamber, where:

[0010] The graphite crucible is placed at the bottom of the plasma arc furnace, and the hollow graphite cathode is placed at a relative position above the graphite crucible, vertically or obliquely inserted into the furnace chamber,

[0011] The growth chamber is provided with an inlet for a carbon source mixed gas;

[0012] A purge gas inlet is provided on the side of the graphite crucible, which is responsible for blowing the evaporated catalyst into the next-stage growth chamber.

[0013] Furthermore, the bottom of the plasma arc furnace is connected to the growth chamber and shares the graphite crucible, forming a channel with a height of 2-30 cm above the graphite crucible;

[0014] The structure of the plasma arc furnace further includes a water-cooled electrode, which is arranged at the bottom of the graphite crucible;

[0015] Among them, the power of the power supply of the plasma arc furnace is 10 - 750 kW, the current is 100 - 10000 A, and the voltage is 1 - 500 V.

[0016] During operation, the graphite crucible heated by the arc furnace provides the heat required for the growth chamber.

[0017] Furthermore, the inner lining of the discharge chamber is made of graphite tube material and has an auxiliary heating function. The power of the auxiliary heating is 5 - 50 kW, and the temperature range is 500 - 1000 °C.

[0018] On the other hand, the present invention provides the following technical solutions:

[0019] A continuous preparation method of high-purity single-walled carbon nanotubes based on any one of the above preparation devices, the method specifically includes the following steps:

[0020] S1) Place the first catalyst in the graphite crucible;

[0021] S2) Evacuate the plasma arc furnace to remove air, then switch to the arc gas. After the pressure is stable, turn on the power supply of the plasma arc furnace to generate a plasma arc, melt the first catalyst in the graphite crucible until the temperature of the growth chamber rises to the specified temperature of 1000 - 1700 °C;

[0022] S3) At the same time, turn on the auxiliary heating of the discharge chamber, and the temperature of the discharge chamber rises to 600 - 1000 °C;

[0023] S4) Introduce an inert gas from the purge gas inlet to bring the catalyst grown in the graphite crucible into the growth chamber;

[0024] S5) After mixing the carbon source gas and the carrier gas, carry the second catalyst and enter the growth chamber through the carbon source mixed gas inlet to start the reaction;

[0025] S6) The reaction product is discharged from the furnace body through the discharge chamber, and the single-walled carbon nanotube product is continuously collected.

[0026] Furthermore, the first catalyst in S1) is iron, cobalt, nickel metal or a mixture thereof.

[0027] Furthermore, the first catalyst in S1) is a mixture of iron, cobalt or nickel and a refractory metal, wherein the refractory metal element is molybdenum, tungsten, tantalum, niobium, hafnium or zirconium, and the content of the refractory metal element is 20 - 80%.

[0028] Furthermore, the arc gas in S2) is any one or a mixed gas of two or more of argon, nitrogen, helium, hydrogen, and water vapor, and the flow rate is 1 L / min - 500 L / min.

[0029] Further, in the step S4), the inert gas is nitrogen, argon or helium, and the flow rate is 0.5 L / min - 20 L / min.

[0030] Further, in the step S5), the carbon source gas is any one of methane, ethylene, acetylene, propylene and propane;

[0031] The carrier gas is a mixture of an inert gas and hydrogen;

[0032] Among them, the volume of the carbon source gas is 10 - 80%, the volume of hydrogen is 1 - 40%, and the rest is an inert gas, and the flow rate is 1 L / min - 200 L / min.

[0033] Further, the second catalyst is any one or a mixture of sulfur powder, selenium powder, iron sulfide, ferrous sulfide, nickel sulfide and cobalt sulfide, and the feeding rate is 0.1 g / min - 100 g / min.

[0034] Compared with the prior art, the continuous preparation device and method of high-purity single-walled carbon nanotubes of the present invention have the following prominent beneficial effects:

[0035] (1) Adopting a structure in which the arc evaporation chamber and the growth chamber are separated and share a crucible, and transferring heat to the growth chamber through the molten metal liquid surface in the crucible, which can effectively reduce the amount of catalyst generated by the plasma arc furnace evaporation entering the growth chamber, and at the same time use the high-temperature heat source in the furnace to provide energy for the subsequent reaction, and by adjusting the channel size, the amount of catalyst can be further finely controlled, and even directly use the heat in the growth chamber to slowly evaporate the bottom electrode catalyst, significantly reducing the amount of ineffective catalyst and improving the purity of the final single-walled carbon nanotube product.

[0036] (2) By adopting the method of injecting a carbon source and a second catalyst into the growth chamber, the utilization rates of the carbon source and the second catalyst are effectively improved, and the deficiency that the contact and reaction between the carbon source and the catalyst are insufficient due to the too fast plasma gas velocity in the conventional plasma method is avoided.

[0037] (3) The plasma arc gas and the carbon source gas are respectively injected into the reaction system by the plasma arc furnace and the growth chamber, avoiding the disadvantage of frequent end arcs caused by the adverse effect of the carbon source gas on the stability of the plasma arc, and truly realizing continuous and stable operation. Description of the Drawings

[0038] Figure 1 is a schematic structural diagram of a continuous preparation device (direct insertion) of single-walled carbon nanotubes of the present invention;

[0039] Figure 2 is a schematic structural diagram of a continuous preparation device (oblique insertion) of single-walled carbon nanotubes of the present invention;

[0040] Figure 3Scanning electron microscope image of the carbon nanotube product prepared in Example 1 of the method of the present invention;

[0041] Figure 4 Raman spectrum of the carbon nanotube product prepared in Example 1 of the method of the present invention;

[0042] Figure 5 Transmission electron microscope image of the carbon nanotube product prepared in Example 1 of the method of the present invention;

[0043] Explanation of reference numerals:

[0044] 1. Water-cooled electrode; 2. Graphite crucible; 3. Purge gas inlet; 4. Plasma arc furnace; 5. Cathodic protection sleeve; 6. Hollow graphite cathode; 7. Carbon source gas mixture inlet; 8. Growth chamber; 9. Discharge chamber. Detailed implementation manners

[0045] The present invention will be further described in detail below with reference to the drawings and embodiments. Example 1

[0046] Adopt the Figure 1 shown single-walled carbon nanotube continuous preparation device, the structure includes a plasma arc furnace 4, a growth chamber 8 and a discharge chamber 9. The water-cooled electrode 1 is arranged at the bottom of the graphite crucible 2, and the hollow graphite cathode 6 is vertically inserted into the furnace chamber. Among them, the power of the plasma arc furnace 4 is 150 kW, the current is 1000 A, and the voltage is 150 V; the bottom of the growth chamber 8 is connected to the plasma arc furnace 4 to form a 5 cm high channel on the graphite crucible 2; the inner lining of the discharge chamber 9 is made of graphite tube material, and the auxiliary heating power is 10 kW;

[0047] Single-walled carbon nanotube preparation process:

[0048] S1) Place the first catalyst, an alloy of 60% iron and 40% molybdenum, in the graphite crucible.

[0049] S2) Turn on the plasma arc furnace to evacuate and remove air, then switch to the arc gas argon with a flow rate of 20 L / min. After the pressure is stable, turn on the arc power supply to generate a plasma arc to melt the first catalyst in the graphite crucible 2 until the temperature of the growth chamber 8 rises to the specified temperature of 1200 °C.

[0050] S3) At the same time, turn on the auxiliary heating of the discharge chamber 9, and the temperature of the discharge chamber 9 rises to the specified temperature of 800 °C.

[0051] S4) Pass the inert gas argon through the purge gas inlet 3 with a flow rate of 5 L / min to bring the grown catalyst into the growth chamber 8.

[0052] S5) Carry the mixed gas of carbon source gas and carrier gas together with the second catalyst sulfur powder into the growth chamber 8 through the carbon source mixed gas inlet 7. The volume fraction of methane in the mixed gas is 40%, hydrogen is 20%, and the rest is argon. The flow rate is 40 L / min. The second catalyst is sulfur powder, and the feeding rate is 20 g / min. Then start the reaction;

[0053] S6) The reaction products are discharged from the furnace body through the discharge chamber 9, and the single-walled carbon nanotube products are continuously collected.

[0054] The above reaction can proceed continuously and stably. After 6 hours of reaction, the products are collected and weighed. The yield of single-walled carbon nanotubes can reach 850 g / h. The products are calcined in a muffle furnace at 900 °C for 2 hours, and the ash is weighed. The purity of the products is calculated to be 86.4%;

[0055] The morphology of the products is observed by a scanning electron microscope as Figure 3 shown. The crystallinity is evaluated by the intensity ratio of the G peak and the D peak in the Raman spectrum, as Figure 4 shown. The G / D ratio is ~72.4;

[0056] Furthermore, the tube diameter and the number of tube walls are observed by a transmission electron microscope, as Figure 5 shown. Example 2

[0057] Use the single-walled carbon nanotube continuous preparation device as Figure 1 shown. The structure includes a plasma arc furnace 4, a growth chamber 8, and a discharge chamber 9. The water-cooled electrode 1 is arranged at the bottom of the graphite crucible 2. The power of the plasma arc furnace 4 is 10 kW, the current is 100 A, and the voltage is 10 V. The bottom of the growth chamber 8 is connected to the plasma arc furnace 4, and a channel with a height of 2 cm is formed on the graphite crucible 2. The inner lining of the discharge chamber 9 is made of graphite tube material, and the auxiliary heating power is 5 kW.

[0058] The preparation process of single-walled carbon nanotubes:

[0059] S1) Place the first catalyst cobalt in the graphite crucible 2;

[0060] S2) Turn on the plasma arc furnace 4 to evacuate and remove air. Then switch to the arc gas, the mixed gas of argon:hydrogen = 2:1, with a flow rate of 1 L / min. After the pressure is stable, turn on the arc power supply to generate a plasma arc, and melt the first catalyst in the graphite crucible 2 until the temperature of the growth chamber 8 rises to the specified temperature of 1000 °C;

[0061] S3) At the same time, turn on the auxiliary heating of the discharge chamber 9, and the temperature of the discharge chamber 9 rises to the specified temperature of 600 °C;

[0062] S4) Introduce inert gas argon through the purge gas inlet 3 at a flow rate of 0.5 L / min to carry the grown catalyst into the growth chamber 8;

[0063] S5) Carry the mixture of carbon source gas and carrier gas together with the second catalyst sulfur powder into the growth chamber 8 through the carbon source gas mixture inlet 7. Among them, the volume fraction in the mixture is 10% methane, 1% hydrogen, and the rest is argon, with a flow rate of 1 L / min. The second catalyst is selenium powder, and the feeding rate is 0.1 g / min, and the reaction starts;

[0064] S6) The reaction products are discharged from the furnace body through the discharge chamber 9, and the single-walled carbon nanotube products are continuously collected.

[0065] The above reaction can proceed continuously and stably. After 6 hours of reaction and ending, the products are collected and weighed. The yield of single-walled carbon nanotubes can reach 25 g / h, and the purity of the products obtained by thermal analysis is 78.1%. Example 3

[0066] Adopt the Figure 1 shown continuous single-walled carbon nanotube preparation device, the structure includes a plasma arc furnace 4, a growth chamber 8 and a discharge chamber 9. The water-cooled electrode 1 is arranged at the bottom of the graphite crucible 2. Among them, the power of the plasma arc furnace 4 is 750 kW, the current is 10000 A, and the voltage is 75 V; the bottom of the growth chamber 8 is connected to the plasma arc furnace 4, and a channel with a height of 30 cm is formed on the graphite crucible 2; the inner lining of the discharge chamber 9 is made of graphite tube material, and the auxiliary heating power is 50 kW.

[0067] Single-walled carbon nanotube preparation process:

[0068] S1) Place the first catalyst ferroalloy in the graphite crucible 2;

[0069] S2) Turn on the plasma arc furnace 4 to evacuate and remove air, then switch to arc gas argon with a flow rate of 500 L / min). After the pressure is stable, turn on the arc power supply to generate a plasma arc to melt the first catalyst in the graphite crucible 2 until the temperature of the growth chamber rises to the specified temperature of 1700 °C;

[0070] S3) At the same time, turn on the auxiliary heating of the discharge chamber 9, and the temperature of the discharge chamber 9 rises to the specified temperature of 1000 °C;

[0071] S4) Introduce inert gas argon through the purge gas inlet 3 at a flow rate of 20 L / min) to carry the grown catalyst into the growth chamber 8;

[0072] S5) Feed the mixed gas of carbon source gas and carrier gas, together with the second catalyst sulfur powder, into the growth chamber 8 through the carbon source mixed gas inlet 7. In the mixed gas, the volume fraction of ethylene is 50%; hydrogen is 40%, and the rest is argon. The flow rate is 200 L / min. The second catalyst is selenium powder, and the feeding rate is 100 g / min. Then start the reaction;

[0073] S6) Discharge the reaction products from the furnace body through the discharge chamber 9, and continuously collect the single-walled carbon nanotube products.

[0074] The reaction can proceed continuously and stably. After 6 hours of reaction, the products are collected and weighed. The yield of single-walled carbon nanotubes can reach 3750 g / h, and the purity of the products obtained by thermal analysis is 75.6%. Example 4

[0075] Adopt the Figure 1 shown continuous single-walled carbon nanotube preparation device, the structure includes a plasma arc furnace 4, a growth chamber 8 and a discharge chamber 9. The water-cooled electrode 1 is arranged at the bottom of the graphite crucible 2. Among them, the power of the plasma arc furnace 4 is 300 kW, the current is 1500 A, and the voltage is 200 V; the bottom of the growth chamber 8 is connected to the plasma arc furnace 4, and a channel with a height of 10 cm is formed on the graphite crucible 2; the inner lining of the discharge chamber 9 is made of graphite tube material, and the auxiliary heating power is 25 kW.

[0076] The process of preparing single-walled carbon nanotubes:

[0077] S1) Place the first catalyst, an iron 60%-nickel 40% alloy, in the graphite crucible 2;

[0078] S2) Turn on the plasma arc furnace 4 to evacuate and remove air, and then switch to the arc gas, an 80%-steam 20% mixed gas of argon, with a flow rate of 250 L / min). After the pressure is stable, turn on the arc power supply to generate a plasma arc, and melt the first catalyst in the graphite crucible until the temperature in the growth chamber rises to the specified temperature of 1000 - 1700 °C;

[0079] S3) At the same time, turn on the auxiliary heating of the discharge chamber 9, and the temperature of the discharge chamber 9 rises to the specified temperature of 800 °C;

[0080] S4) Pass the inert gas argon through the purge gas inlet 3 at a flow rate of 10 L / min), and carry the grown catalyst into the growth chamber 8;

[0081] S5) Feed the mixed gas of carbon source gas and carrier gas, together with the second catalyst ferrous sulfide powder, into the growth chamber 8 through the carbon source mixed gas inlet 7. In the mixed gas, the volume fraction of propylene is 80%; hydrogen is 10%, and the rest is argon. The flow rate is 100 L / min. The second catalyst is ferrous sulfide, and the feeding rate is 50 g / min. Then start the reaction;

[0082] S6) The reaction product is discharged from the furnace body through the discharge chamber 9, and the single-walled carbon nanotube product is continuously collected.

[0083] The reaction can proceed continuously and stably. After 6 hours of reaction, the product is collected and weighed. The yield of single-walled carbon nanotubes can reach 1460 g / h, and the purity of the product obtained by thermal analysis is 85.4%. Example 5

[0084] Adopt the Figure 2 shown continuous single-walled carbon nanotube preparation device, the structure includes a plasma arc furnace 4, a growth chamber 8 and a discharge chamber 9. The water-cooled electrode 1 is arranged at the bottom of the graphite crucible 2, and the hollow graphite cathode 6 is obliquely inserted into the furnace chamber. Among them, the power of the plasma arc furnace 4 is 300 kW, the current is 1500 A, and the voltage is 200 V; the bottom of the growth chamber 8 is connected to the plasma arc furnace 4, and a channel with a height of 10 cm is formed on the graphite crucible 2; the inner lining of the discharge chamber 9 is made of graphite tube material, and the auxiliary heating power is 25 kW.

[0085] The process of preparing single-walled carbon nanotubes:

[0086] S1) Place the first catalyst, an alloy of 30% iron - 30% cobalt - 40% tantalum, in the graphite crucible 2;

[0087] S2) Turn on the plasma arc furnace 4 to evacuate and remove air, then switch to the arc gas, a mixture of 60% argon - 30% hydrogen - 10% water vapor, with a flow rate of 250 L / min). After the pressure is stable, turn on the arc power supply to generate a plasma arc, melt the first catalyst in the graphite crucible 2 until the temperature of the growth chamber 8 rises to the specified temperature of 1000 - 1700 °C;

[0088] S3) At the same time, turn on the auxiliary heating of the discharge chamber 9, and the temperature of the discharge chamber 9 rises to the specified temperature of 700 °C;

[0089] S4) Pass the inert gas argon through the purge gas inlet 3 at a flow rate of 10 L / min), and carry the grown catalyst into the growth chamber;

[0090] S5) Carry the second catalyst sulfur powder together with the mixture of carbon source gas and carrier gas through the carbon source mixture inlet 7 into the growth chamber 8. Among them, the volume fraction in the mixture is 30% methane; 30% hydrogen, and the rest is argon, with a flow rate of 100 L / min. The second catalyst is nickel sulfide, and the feeding rate is 30 grams per minute, and the reaction starts;

[0091] S6) The reaction product is discharged from the furnace body through the discharge chamber 9, and the single-walled carbon nanotube product is continuously collected.

[0092] The reaction can proceed continuously and stably. After 6 hours of reaction, the product is collected and weighed. The yield of single-walled carbon nanotubes can reach 1748 g / h, and the purity of the product obtained by thermal analysis is 83.6%.

[0093] Comparative Example 1

[0094] This comparative example has the same equipment parameters and experimental parameters as Example 1. The difference is that there is no separation between the evaporation chamber and the growth chamber in the comparative example, and the carbon source gas mixture, the second catalyst, and the arc gas all enter the arc furnace through the hollow graphite electrode. Due to the discontinuous reaction, only a 2-hour experiment can be carried out. The product is collected and the yield is calculated to be ~240 g / h, and the purity of the product obtained by thermal analysis is 41.5%.

[0095] Table 1 Summary and Comparison of Experimental Results of Examples

[0096] Example Power kW Voltage V Current A First catalyst Yield g / h Purity Example 1 150 150 1000 Fe60%-Mo40% 850 86.4% Example 2 10 10 100 Co 25 78.1% Example 3 750 75 10000 Fe 3750 75.6% Example 4 300 200 1500 Fe60%-Ni40% 1460 85.4% Example 5 300 200 1500 Fe30%-Co30%-Ta40% 1748 83.6% Comparative Example 1 150 150 1000 Fe60%-Mo40% 240 41.5%

[0097] It can be seen from the comparison results in Table 1 that the present invention can greatly improve the yield and the purity of the product.

[0098] The above-described embodiments are only relatively preferred specific embodiments of the present invention. Any ordinary variations and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A continuous preparation device for high-purity single-walled carbon nanotubes, characterized in that: The structure of the device comprises a plasma arc furnace (4), a growth chamber (8) and a discharge chamber (9) which are arranged in sequence; The structure of the plasma arc furnace (4) comprises a hollow graphite cathode (6), a graphite crucible (2) serving as an anode, and a furnace, wherein: The graphite crucible (2) is placed at the bottom of the plasma arc furnace (4), and the hollow graphite cathode (6) is placed at a relative position above the graphite crucible (2); The growth chamber (8) is provided with a carbon source mixed gas inlet (7); A purge gas inlet (3) is provided on the side of the graphite crucible, which is responsible for blowing the catalyst produced by evaporation into the next growth chamber (8); The bottom of the plasma arc furnace (4) and the growth chamber (8) are connected and share a graphite crucible (2), and a channel with a height of 2-30 cm is formed above the graphite crucible (2); The structure of the plasma arc furnace (4) further comprises a water-cooled electrode (1) arranged at the bottom of the graphite crucible (2); The power supply of the plasma arc furnace (4) is 10~750 kW, the current is 100~10000 A, and the voltage is 1~500 V.

2. The device for continuously preparing high-purity single-walled carbon nanotubes according to claim 1, characterized in that: The discharge chamber (9) is lined with graphite tube material and has an auxiliary heating function. The power of the auxiliary heating is 5-50 kW and the temperature range is 500-1000°C.

3. A method for continuously preparing a high-purity single-walled carbon nanotube according to claim 1 or 2, characterized in that: The method specifically comprises the following steps: S1) placing a first catalyst in a graphite crucible (2); S2) evacuating the plasma arc furnace (4) to remove air, then switching to arc gas, and turning on the power supply of the plasma arc furnace (4) after the pressure stabilizes to generate a plasma arc to melt the first catalyst in the graphite crucible (2) until the temperature of the growth chamber (8) rises to a specified temperature of 1000-1700° C.; S3) At the same time, the auxiliary heating of the discharge chamber (9) is turned on, and the temperature of the discharge chamber (9) is raised to 600-1000°C. S4) introducing an inert gas from the purge gas inlet (3) to bring the catalyst grown in the graphite crucible (2) into the growth chamber; S5) mixing the carbon source gas and the carrier gas, and carrying the second catalyst together, into the growth chamber through the carbon source mixed gas inlet (7) to start the reaction; S6) The reaction product is discharged from the furnace through the discharge chamber (9) and continuously collected to obtain single-walled carbon nanotube products.

4. The method of a continuous preparation device for high-purity single-walled carbon nanotubes according to claim 3, characterized in that: The first catalyst in S1) is iron, cobalt, nickel or a mixture thereof.

5. The method of a continuous preparation device for high-purity single-walled carbon nanotubes according to claim 3, characterized in that: The first catalyst in S1) is a mixture of iron, cobalt or nickel and a refractory metal, wherein the refractory metal element is molybdenum, tungsten, tantalum, niobium, hafnium or zirconium, and the content of the refractory metal element is 20-80%.

6. The method for continuously preparing high-purity single-walled carbon nanotubes according to claim 4 or 5, characterized in that: The arc gas in S2) is any one of argon, nitrogen, helium, hydrogen, and water vapor, or a mixture of two or more of them in any ratio, with a flow rate of 1 L / min-500 L / min.

7. The method of a continuous preparation device for high-purity single-walled carbon nanotubes according to claim 6, characterized in that: In step S4), the inert gas is nitrogen, argon or helium, and the flow rate is 0.5L / min-20L / min.

8. The method of a continuous preparation device for high-purity single-walled carbon nanotubes according to claim 6, characterized in that: In step S5), the carbon source gas is any one of methane, ethylene, acetylene, propylene and propane; the carrier gas is a mixture of an inert gas and hydrogen; The volume of the carbon source gas is 10-80%, the volume of hydrogen is 1-40%, and the rest is inert gas, with a flow rate of 1 L / min-200 L / min.

9. The method of a continuous preparation device for high-purity single-walled carbon nanotubes according to claim 6, characterized in that: The second catalyst is any one of sulfur powder, selenium powder, iron sulfide, ferrous sulfide, nickel sulfide, cobalt sulfide or a mixture thereof, and the feed rate is 0.1 g / min-100 g / min.

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