Production equipment of single-walled carbon nanotube and control method thereof

Abstract

The invention discloses single-walled carbon nanotube production equipment and a control method thereof, and belongs to the technical field of single-walled carbon nanotube production. The production equipment comprises a main reactor as well as an arc plasma torch assembly and a catalyst assembly which are mounted on the main reactor, and the arc plasma torch assembly and the catalyst assembly respectively extend into the main reactor and are arranged at intervals; a catalyst supplementing opening is formed in the upper side of the main reactor and is communicated with a catalyst feeding assembly through a catalyst supplementing pipeline; and the control unit is used for controlling the state of the catalyst supply assembly according to the voltage value of the arc plasma torch assembly. The invention solves the problem of production interruption caused by unstable electric arc between the cathode and the anode of the existing single-walled carbon nanotube production equipment.

Description

Technical Field

[0001] The invention relates to the technical field of single-walled carbon nanotube production, and in particular to single-walled carbon nanotube production equipment and a control method thereof. Background Art

[0002] The arc discharge method is a commonly used method for preparing single-walled carbon nanotubes. The preparation principle is to introduce carbon-containing gas into a vacuum container, use transition metal as a catalyst to form a cathode, and use a tungsten needle as an anode. The argon gas is broken down and ionized by the high voltage between the cathode and the anode to form a stable arc. During the arc discharge process, the metal catalyst in the receiving electrode is vaporized and forms nano-scale droplets in the reaction container. The carbon-containing gas attaches to the metal droplets under the high temperature environment in the reaction container and dehydrogenates, thereby producing single-walled carbon nanotubes.

[0003] At present, in the production equipment for preparing single-walled carbon nanotubes, when an arc is generated between the anode and cathode to vaporize the metal catalyst, the amount of catalyst in the catalyst container gradually decreases, which will cause the gap between the anode and cathode to be too large, the arc between the two to be unstable, and ultimately lead to production interruption. Summary of the invention

[0004] The technical problem to be solved by the present invention is the problem of production interruption caused by unstable arc between the cathode and anode of existing single-walled carbon nanotube production equipment.

[0005] In view of the above technical problems, the present invention provides the following technical solutions:

[0006] A single-wall carbon nanotube production device comprises: a main reactor and an arc plasma torch assembly and a catalyst assembly installed on the main reactor, wherein the arc plasma torch assembly and the catalyst assembly extend into the main reactor respectively and are arranged at intervals; a catalyst replenishing port is arranged on the upper side of the main reactor, and the catalyst replenishing port is connected to a catalyst feeding assembly through a catalyst replenishing pipeline; and a control unit, wherein the control unit controls the state of the catalyst feeding assembly according to the voltage value between the arc plasma torch assembly and the catalyst assembly.

[0007] In some embodiments of the present invention, when the voltage value between the arc plasma torch assembly and the catalyst assembly is higher than a first threshold value, the control unit controls the catalyst supply assembly to open the supply pipeline, and closes the supply pipeline after supplying at a first flow rate for a first set time.

[0008] In some embodiments of the present invention, the catalyst feeding assembly includes a feeding hopper for accommodating catalyst particles, a rotary feeding valve is provided at the bottom of the feeding hopper, a rotary motor is connected to the rotary feeding valve, and the rotary motor controls the opening or closing of the rotary feeding valve.

[0009] In some embodiments of the present invention, the catalyst supply assembly further includes a discharge pipeline disposed at an outlet side of the rotary supply valve, and the discharge pipeline is connected to the catalyst replenishment pipeline via a flange.

[0010] In some embodiments of the present invention, the catalyst feeding assembly further comprises a feeding cover having a sealing cover disposed on the feeding hopper, the feeding cover is provided with a protective gas inlet, and the protective gas inlet is connected to a protective gas supply system.

[0011] In some embodiments of the present invention, it also includes a reactor shell covering the outside of the main reactor, and the space between the reactor shell and the main reactor is filled with insulation material. The arc plasma torch assembly and the catalyst assembly extend along the reactor shell into the inside of the main reactor.

[0012] In some embodiments of the present invention, the catalyst assembly is installed on the lower side wall of the main reactor, and includes a catalyst accommodating portion, which is used to accommodate a solid catalyst whose shape matches the catalyst assembly; the catalyst replenishing port is located on the upper side wall of the main reactor and is opposite to the catalyst accommodating portion.

[0013] The present invention also provides a control method for single-walled carbon nanotube production equipment, comprising: controlling an arc generator connected to an arc plasma torch assembly to start up so as to generate an arc between the arc plasma torch assembly and a catalyst assembly, and when receiving a detection signal indicating that a voltage value between the arc plasma torch assembly and the catalyst assembly is lower than a second threshold, controlling a feed gas to enter the main reactor.

[0014] In some embodiments of the present invention, when a detection signal is received that the voltage value between the arc plasma torch assembly and the catalyst assembly is higher than a first threshold value, the catalyst feeding assembly is controlled to open the feeding pipeline, and close the feeding pipeline after feeding at a first flow rate for a first set time.

[0015] In some embodiments of the present invention, when a detection signal is received that the voltage value between the arc plasma torch assembly and the catalyst assembly is higher than a first threshold value, the catalyst feeding assembly is controlled to open the feeding pipeline and feed at a first flow rate until a detection signal is received that the voltage value between the arc plasma torch assembly and the catalyst assembly is lower than a third threshold value, and then the feeding pipeline is closed.

[0016] The technical solution of the present invention has the following technical effects compared with the prior art:

[0017] In the single-walled carbon nanotube production equipment provided by the present invention, when the gap between the arc plasma torch assembly and the catalyst assembly is greater than a set threshold value, the control unit controls the state of the catalyst feeding assembly according to the voltage value between the arc plasma torch assembly and the catalyst assembly, so that the metal catalyst of the catalyst feeding assembly enters into the catalyst containing part along the catalyst replenishment pipeline and the catalyst replenishment port to replenish the catalyst, so that the voltage between the arc plasma torch assembly and the catalyst assembly is restored to within the set threshold value, thereby solving the problem of production interruption caused by unstable arc between the anode and cathode of the existing single-walled carbon nanotube production equipment and realizing continuous production of single-walled carbon nanotubes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, which will help to understand the objects and advantages of the present invention, wherein:

[0019] Figure 1 A schematic diagram of a specific embodiment of the single-walled carbon nanotube preparation device of the present invention;

[0020] Figure 2 It is a structural schematic diagram of a specific embodiment of the arc plasma torch assembly of the present invention;

[0021] Figure 3 A partial schematic diagram of a specific embodiment of the single-walled carbon nanotube preparation device of the present invention;

[0022] Figure 4 A three-dimensional diagram of a catalyst feeding assembly in the single-walled carbon nanotube preparation device of the present invention;

[0023] Figure 5 It is a cross-sectional view of a catalyst supply assembly in the single-walled carbon nanotube preparation device of the present invention. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] like Figure 1 , Figure 2 The figure shows a specific embodiment of the single-walled carbon nanotube production equipment of the present invention, comprising: the preparation equipment comprises a main reactor 10, the main reactor 10 comprises a catalyst gasification chamber 10a and a carbon nanotube generation chamber 10b which are interconnected, the catalyst gasification chamber 10a extends in a horizontal direction and a feed port 13 is provided at a first end thereof, the carbon nanotube generation chamber 10b extends in a vertical direction and a discharge port 14 is provided at a lower end thereof; and an arc plasma torch assembly 20 and a catalyst assembly 30 respectively installed at the upper and lower sides of the catalyst gasification chamber 10a; the arc plasma torch assembly 20 and the catalyst assembly 30 respectively extend into the main reactor 10 and are arranged at intervals, The arc plasma torch assembly 20 is connected to an arc generator (not shown in the figure), and an arc is generated between the arc plasma torch assembly 20 and the catalyst assembly 30, so that the metal catalyst in the catalyst assembly 30 is vaporized and enters the catalyst gasification chamber 10a to form nanometer-scale droplets; the feed gas (such as methane and other carbon-containing organic matter) enters the catalyst gasification chamber 10a along the feed port 13 of the main reactor 10 and is cracked and dehydrogenated in a high-temperature environment, and the reaction product is attached to the catalyst droplets and enters the carbon nanotube generation chamber 10b along the catalyst gasification chamber 10a to complete the growth and finally form single-walled carbon nanotubes and are discharged along the discharge port, thereby realizing the continuous preparation of single-walled carbon nanotubes.

[0029] like Figure 2As shown, the arc plasma torch assembly 20 includes a plasma generating body 21 and an emitter 22 installed inside the plasma generating body 21, the emitter 22 includes a conductive tube 221 extending along a first direction and an emitter nozzle 222 located at the end of the conductive tube 221; wherein the emitter nozzle 222 is made of metal tungsten, and the conductive tube 221 is made of metal copper, the emitter nozzle 222 is plugged into the end of the conductive tube 221, the conductive tube 221 is electrically connected to the arc generator, and the arc generator is controlled to be turned on so that an arc can be generated between the emitter 22 of the arc plasma torch assembly 20 and the catalyst surface of the catalyst assembly 30; a gas channel 22a is provided in the conductive tube 221 and the emitter nozzle 222 for supplying a protective gas, specifically, the protective gas is argon, and the argon is broken down and ionized by the high voltage between the cathode and anode to form a stable arc.

[0030] Specifically, in an optional implementation manner, Figure 3 As shown, the catalyst assembly 30 includes a catalyst containing part 31 with an upper opening, the catalyst containing part 31 is used to contain a solid catalyst 32 with a shape matching therewith, and a connection hole for connecting a receiving pole 33 is provided at the bottom of the catalyst containing part 31, and the receiving pole 33 is connected to the solid catalyst 32 through the connection hole. The solid catalyst 32 is made of metal materials such as iron, cobalt, nickel, and molybdenum, and the receiving pole 33 is made of metal materials such as copper and silver.

[0031] When an arc is generated between the arc plasma torch assembly 20 and the catalyst assembly 30 to vaporize the metal catalyst, the amount of catalyst in the catalyst container 31 gradually decreases, which will cause the gap between the arc plasma torch assembly 20 and the catalyst assembly 30 to be too large, and there is not enough space between the two to generate an arc, which eventually leads to the problem of production interruption. In order to ensure the continuous preparation of single-walled carbon nanotubes, such as Figure 1 As shown, the main reactor 10 is provided with a catalyst replenishing port 12 on the upper side wall directly opposite to the catalyst assembly 30, and the catalyst replenishing port 12 is connected to the catalyst supply assembly 70 through the catalyst replenishing pipeline 60. When the gap between the arc plasma torch assembly 20 and the catalyst assembly 30 is greater than the set threshold, the control unit controls the state of the catalyst supply assembly 70 according to the voltage value between the arc plasma torch assembly 20 and the catalyst assembly 30, so that the metal catalyst of the catalyst supply assembly 70 enters the catalyst containing part 31 along the catalyst replenishing pipeline 60 and the catalyst replenishing port 12, thereby realizing the continuous production of single-walled carbon nanotubes.

[0032] Specifically, in an optional implementation manner, Figure 4 , Figure 5As shown, the catalyst supply assembly 70 includes a supply hopper 71 for accommodating catalyst particles, a rotary supply valve 72 is provided at the bottom of the supply hopper 71, a rotary motor 73 is connected to the rotary supply valve 72, and the control unit controls the rotary motor 73 to control the opening or closing state of the rotary supply valve 72. More specifically, the rotary motor 73 is a servo motor, and the servo motor is controlled to rotate a first set angle so that the valve port of the rotary supply valve 72 opens a first set angle, so that the catalyst particles in the supply hopper 71 pass along the valve port and enter the catalyst containing portion along the catalyst replenishing pipeline 60 and the catalyst replenishing port 12.

[0033] Specifically, in an optional embodiment, the catalyst feeding assembly 70 also includes a discharge pipeline 74 arranged on the outlet side of the rotary feeding valve 72, and the discharge pipeline 74 is connected to the catalyst replenishing pipeline 60 through a flange to facilitate the overall installation and disassembly of the catalyst feeding assembly 70 and subsequent maintenance.

[0034] Specifically, in an optional embodiment, since the reaction chamber of the main reactor 10 is in a negative pressure state when preparing single-walled carbon nanotubes, in order to ensure the negative pressure state of the entire reaction chamber, the catalyst feeding assembly 70 also includes a feeding cover 75 with a sealing cover arranged on the feeding hopper 71, and the feeding cover 75 is provided with a protective gas inlet 75a, and the protective gas inlet 75a is connected to a protective gas supply system, wherein the protective gas supply system is used to supply protective gases such as nitrogen or argon to avoid safety hazards caused by the entry of outside air into the main reactor 10.

[0035] like Figure 1 As shown, the preparation equipment also includes a reactor shell 40 covered on the outside of the main reactor 10, the arc plasma torch assembly 20 and the catalyst assembly 30 extend into the inside of the main reactor 10 along the reactor shell 40, and the reactor shell 40 and the main reactor 10 are filled with insulation material. Since the single-walled carbon nanotubes have high requirements for the reaction temperature, in order to ensure the temperature stability of the catalyst gasification chamber 10a and the carbon nanotube generation chamber 10b, the insulation material between the reactor shell 40 and the main reactor 10 can avoid excessive changes in the reaction temperature. More specifically, the inner wall of the reactor shell 40 is provided with a heat insulation layer, which can isolate the temperature field of the outside and inside of the reactor shell 40, avoiding the safety hazard caused by the excessively high temperature of the outside of the reactor shell 40.

[0036] Specifically, in one embodiment, the catalyst replenishing pipeline 60 extends upward along the catalyst replenishing port 12 to the outside of the reactor shell 40 and is connected to the catalyst supply assembly 70 .

[0037] The main reactor 10 is an inverted L-shaped tube as a whole, and at least part of the horizontal branch of the L-shaped tube forms a catalyst gasification chamber 10a, and at least part of the vertical branch of the L-shaped tube forms a carbon nanotube generation chamber 10b. The catalyst gasification chamber 10a is connected to the carbon nanotube generation chamber 10b through an arc-shaped transition chamber, which can facilitate the rapid discharge of the reaction products into the carbon nanotube generation chamber 10b. Among them, the flow cross-sectional area of ​​the catalyst gasification chamber 10a is larger than the flow cross-sectional area of ​​the carbon nanotube generation chamber 10b, which can make the chamber volume of the catalyst gasification chamber 10a larger, and the temperature field is evenly distributed, which is conducive to the cracking reaction of the feed gas in each area of ​​the space to be more complete and the reaction effect is good. Among them, the flow cross-sectional area of ​​the carbon nanotube generation chamber 10b is determined according to the set flow rate of the reactants in this chamber. By setting the flow cross-sectional size of the carbon nanotube generation chamber 10b, the flow rate of the reaction products in this chamber can be changed, and then the residence time of the reaction products in this chamber can be changed. After the heat-insulating flow for the set residence time, the production quality of the single-walled carbon nanotube product can be guaranteed.

[0038] In an optional embodiment, the arc plasma torch assembly 20 has an angle with the horizontal direction that is not 0°, that is, the extension direction of the plasma generating body 21 or the emitter 22 is inclined relative to the horizontal direction; the catalyst assembly 30 extends in the vertical direction, that is, the catalyst receiving portion 31 extends in the vertical direction so that the upper surface of the solid catalyst 32 located therein extends in the horizontal direction. When the arc heats the solid catalyst 32 at high temperature, the high-temperature catalyst liquid will sputter to the surroundings, and the emission nozzle 222 is at a certain angle to the surface of the solid catalyst 32, so that the argon gas blown from the emission nozzle 222 can quickly blow away the sputtered droplets, thereby preventing the emission nozzle 222 from being ablated.

[0039] The present invention also provides a specific implementation of a control method for the above-mentioned single-walled carbon nanotube production equipment, the control method comprising: controlling the arc generator to start so that an arc is generated between the arc plasma torch assembly 20 and the catalyst assembly 30, at which time the voltage value between the arc plasma torch assembly 20 and the catalyst assembly 30 is detected to be a first voltage value, for example, the first voltage value is 20V, when a detection signal is received that the voltage value between the arc plasma torch assembly 20 and the catalyst assembly 30 is lower than a second threshold value, for example, when the second threshold value is 24V, the feed gas is controlled to enter the main reactor 10, the carbon-containing feed gas is cracked and dehydrogenated in a high-temperature environment, and the reaction product is attached to the catalyst droplets and enters the carbon nanotube generation chamber 10b along the catalyst gasification chamber 10a to complete growth and finally form single-walled carbon nanotubes and are discharged along the discharge port 14, thereby realizing the continuous preparation of single-walled carbon nanotubes.

[0040] Specifically, in an optional embodiment, when a detection signal is received that the voltage value between the arc plasma torch assembly 20 and the catalyst assembly 30 is higher than a first threshold value, for example, when the first threshold value is 26V, the catalyst feeding assembly 70 is controlled to open the feeding pipeline, and the feeding pipeline is closed after feeding at a first flow rate for a first set time, that is, the rotating motor 73 is controlled to rotate a first set angle to open the first valve port area of ​​the rotary feeding valve 72, so that the catalyst particles in the feeding bin are replenished into the catalyst containing portion 31 along the catalyst supply pipeline and the catalyst replenishment port 12; when the catalyst particles are supplied for the first set time, the catalyst in the catalyst containing portion is replenished to the amount, the distance between the arc plasma torch assembly 20 and the catalyst assembly 30 becomes smaller, and when the voltage value between the arc plasma torch assembly 20 and the catalyst assembly 30 reaches a second threshold value, the rotating motor 73 is controlled to rotate a second set angle to rotate the rotary feeding valve 72 to a closed position.

[0041] Specifically, in another optional embodiment, when a detection signal is received that the voltage value between the arc plasma torch assembly 20 and the catalyst assembly 30 is higher than a first threshold value, for example, when the first threshold value is 26V, the catalyst feeding assembly 70 is controlled to open the feeding pipeline and feed at a first flow rate, that is, the rotary motor 73 is controlled to rotate a first set angle so that the rotary feeding valve 72 opens a first valve port area, so that the catalyst particles in the feeding bin are replenished into the catalyst containing portion 31 along the catalyst supply pipeline and the catalyst replenishment port 12; until a detection signal is received that the voltage value between the arc plasma torch assembly 20 and the catalyst assembly 30 is lower than a third threshold value, for example, when the third threshold value is 24V, the rotary motor 73 is controlled to rotate a second set angle so that the rotary feeding valve 72 rotates to a closed position to close the feeding pipeline.

[0042] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A production device for single-walled carbon nanotubes, It is characterized in that include: A main reactor and an arc plasma torch assembly and a catalyst assembly installed on the main reactor, wherein the arc plasma torch assembly and the catalyst assembly extend into the main reactor respectively and are arranged at intervals; A catalyst replenishing port is provided on the upper side of the main reactor, and the catalyst replenishing port is connected to the catalyst supply assembly through a catalyst replenishing pipeline; A control unit controls the state of the catalyst supply assembly according to a voltage value between the arc plasma torch assembly and the catalyst assembly.

2. The single-walled carbon nanotube production device according to claim 1, It is characterized in that When the voltage value between the arc plasma torch assembly and the catalyst assembly is higher than a first threshold value, the control unit controls the catalyst supply assembly to open a supply pipeline, and closes the supply pipeline after supplying at a first flow rate for a first set time.

3. A single-walled carbon nanotube production device according to claim 1 or 2, It is characterized in that The catalyst feeding assembly comprises a feeding hopper for accommodating catalyst particles. A rotary feeding valve is arranged at the bottom of the feeding hopper. A rotary motor is connected to the rotary feeding valve, and the rotary motor controls the opening or closing of the rotary feeding valve.

4. The single-walled carbon nanotube production device according to claim 3, It is characterized in that The catalyst supply assembly further comprises a discharge pipeline arranged at the outlet side of the rotary supply valve, and the discharge pipeline is connected to the catalyst replenishment pipeline via a flange.

5. The single-walled carbon nanotube production device according to claim 4, It is characterized in that The catalyst feeding assembly also includes a feeding cover with a sealing cover arranged on the feeding hopper, and a protective gas inlet is arranged on the feeding cover, and the protective gas inlet is communicated with a protective gas supply system.

6. A single-walled carbon nanotube production device according to claim 1 or 2, It is characterized in that It also includes a reactor shell which is covered on the outside of the main reactor, the space between the reactor shell and the main reactor is filled with heat preservation material, and the arc plasma torch assembly and the catalyst assembly extend along the reactor shell into the inside of the main reactor.

7. A single-walled carbon nanotube production device according to claim 1 or 2, It is characterized in that The catalyst assembly is installed on the lower side wall of the main reactor, and includes a catalyst containing portion, wherein the catalyst containing portion is used to contain a solid catalyst having a shape matching the catalyst. The catalyst replenishing port is located on the upper side wall of the main reactor and is directly opposite to the catalyst containing portion.

8. A control method for a single-walled carbon nanotube production device, It is characterized in that include: An arc generator connected to the arc plasma torch assembly is controlled to start so as to generate an arc between the arc plasma torch assembly and the catalyst assembly. When a detection signal is received indicating that the voltage value between the arc plasma torch assembly and the catalyst assembly is lower than a second threshold, the feed gas is controlled to enter the main reactor.

9. The control method of the single-walled carbon nanotube production equipment according to claim 8, It is characterized in that When a detection signal is received indicating that the voltage value between the arc plasma torch assembly and the catalyst assembly is higher than a first threshold value, the catalyst supply assembly is controlled to open a supply pipeline, and the supply pipeline is closed after supplying at a first flow rate for a first set time.

10. The control method of the single-walled carbon nanotube production equipment according to claim 8, It is characterized in that When a detection signal is received that the voltage value between the arc plasma torch assembly and the catalyst assembly is higher than a first threshold value, the catalyst supply assembly is controlled to open the supply pipeline and supply at a first flow rate until a detection signal is received that the voltage value between the arc plasma torch assembly and the catalyst assembly is lower than a third threshold value, and then the supply pipeline is closed.

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