Efficient production equipment for single-walled carbon nanotubes

Abstract

The utility model discloses high-efficiency production equipment for a single-walled carbon nanotube. The production equipment comprises a vacuum closed box and a high-temperature growth furnace, a conveying device is arranged in the vacuum closed box, and a growth matrix is placed on the conveying device; a sample feeding cylinder corresponding to the conveying device is arranged in the vacuum closed box; a growth quartz tube is arranged in the high-temperature growth furnace and is connected with an outlet of the vacuum closed box; the sample feeding cylinder can feed the growth substrate into the growth quartz tube; the growth quartz tube is also connected with a carbon source supply system; the production equipment further comprises a sampling air cylinder, and the sampling air cylinder is used for sending the growth matrix loaded with the single-walled carbon nanotubes out of the high-temperature growth furnace. According to the production equipment and the production method, not only can the single-walled carbon nanotubes which are relatively pure and relatively good in uniformity be produced, but also the automation degree is high, the production efficiency is relatively high, and continuous production of the single-walled carbon nanotubes can be realized.

Description

Technical Field

[0001] The utility model relates to the technical field of carbon nanotubes, in particular to a high-efficiency production device for single-walled carbon nanotubes. Background Art

[0002] Carbon nanotubes (CNTs) are a tubular structure with a continuous hexagonal carbon atom structure. They can be understood as a tubular structure formed by curling graphene. Single-walled carbon nanotubes can be seen as seamless hollow two-dimensional tubular structures formed by curling a single layer of graphene in a certain direction. The uniqueness of this structure makes single-walled carbon nanotubes have excellent mechanical properties, chirality-dependent conductive / semiconductor properties, ballistic transport characteristics, excellent flexibility and high chemical stability, etc., and are expected to be widely used in high-tech fields such as aviation, aerospace, and nanoelectronic devices.

[0003] At present, the main methods for preparing carbon nanotubes are: arc discharge method, laser ablation method, chemical vapor deposition method, solid phase pyrolysis method, glow discharge method, gas combustion method, polymerization reaction synthesis method, etc. Chemical vapor deposition technology has become the mainstream method for preparing single-walled carbon nanotubes due to its advantages such as simple process and equipment, low cost, and controllable structure. The chemical vapor deposition method for commercial production of carbon nanotubes mainly uses the catalyst impregnation / coating on a certain substrate, such as porous zeolite, MgO, silicon substrate, etc. Under appropriate temperature and carbon source supply conditions, carbon nanotubes can grow from the catalyst supported by the substrate.

[0004] The current carbon nanotube chemical vapor deposition production equipment has a low degree of automation and low production efficiency, and is unable to mass-produce single-walled carbon nanotubes. Utility Model Content

[0005] In order to solve the above technical problems, the purpose of the utility model is to provide a single-walled carbon nanotube efficient production equipment. The production equipment can not only produce relatively pure and uniform single-walled carbon nanotubes, but also has a high degree of automation and high production efficiency, and can realize the continuous production of single-walled carbon nanotubes.

[0006] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0007] The utility model provides a single-wall carbon nanotube high-efficiency production device, which includes a vacuum sealed box and a high-temperature growth furnace;

[0008] The vacuum sealed box is provided with a conveying device, on which the growth substrate is placed; the vacuum sealed box is also provided with a sample delivery cylinder corresponding to the conveying device;

[0009] The high temperature growth furnace is provided with a growth quartz tube, and the growth quartz tube is connected to the outlet of the vacuum sealed box; the sample delivery cylinder can deliver the growth substrate into the growth quartz tube; the growth quartz tube is also connected to a carbon source supply system;

[0010] It also includes a sampling cylinder; the sampling cylinder is used to send the growth substrate carrying the grown single-walled carbon nanotubes out of the high-temperature growth furnace.

[0011] Furthermore, the growth substrate is a quartz carrier loaded with catalyst particles.

[0012] Furthermore, the conveying device is a conveyor belt, and the conveyor belt is driven by a motor.

[0013] Furthermore, a gate valve is provided at the outlet of the vacuum sealed box and between the growth quartz tube and the cooling quartz tube.

[0014] Furthermore, the vacuum sealed box is connected to a first vacuum pump, and the growth quartz tube is connected to a second vacuum pump.

[0015] Furthermore, the pressure in the growth quartz tube is controlled to be 0.5-3Kpa.

[0016] Furthermore, the piston rod of the sampling cylinder extends into the growth quartz tube, and an elastic hook is provided at the end thereof for hooking the growth substrate carrying the grown single-walled carbon nanotubes away from the growth quartz tube.

[0017] Furthermore, the production equipment also includes a cooling quartz tube, which is connected to the growth quartz tube.

[0018] Furthermore, the growth quartz tube and the cooling quartz tube are both provided with a support seat for supporting the growth substrate.

[0019] Furthermore, the carbon source supply system is used to provide a carbon source mixed gas, which includes a reducing gas, a protective gas and a carbon source gas containing ethanol.

[0020] The beneficial effects of the utility model are:

[0021] (1) The utility model uses a sample delivery cylinder built into a vacuum sealed box to deliver the growth substrate, which can reduce equipment costs, make operation more convenient, and achieve more accurate and efficient sample delivery operations;

[0022] (2) The utility model uses a sampling cylinder to send the growth substrate carrying single-walled carbon nanotubes out of the high-temperature growth furnace through the elastic hook at the end of its piston rod, and then send it into the cooling quartz tube for cooling. This sampling cylinder can be well adapted to the growth quartz tube, improve the convenience of sampling operation, reduce equipment costs, and achieve more accurate and efficient sampling operations;

[0023] (3) The utility model designs a cooling quartz tube at the outlet of the high-temperature growth furnace, which can facilitate the timely cooling of the single-walled carbon nanotube products without the need to transfer them to other cooling equipment for cooling, thereby improving production efficiency;

[0024] (4) While the previous single-walled carbon nanotube is in the cooling process, the next growth substrate is transported to the position by the transport device, and the production of the next single-walled carbon nanotube is carried out, thus realizing continuous production.

[0025] The production equipment of the utility model is enlarged to more than 100 times of the traditional equipment, and the reaction pressure and temperature are reasonably controlled. Not only can relatively pure and uniform single-walled carbon nanotubes be produced, but also the degree of automation is high and the production efficiency is high, and the continuous production of single-walled carbon nanotubes can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the three-dimensional structure of the high-efficiency production equipment of single-walled carbon nanotubes of the utility model.

[0027] Figure 2 It is a partial structural schematic diagram of the single-walled carbon nanotube efficient production equipment of the utility model.

[0028] Figure 3 This is a schematic diagram of part of the internal structure of the single-walled carbon nanotube efficient production equipment of the present utility model.

[0029] Figure 4 It is a schematic diagram of the enlarged structure of the elastic hook.

[0030] Figure 5 This is an electron microscope image of the single-walled carbon nanotube produced by the utility model.

[0031] In the figure, 1: vacuum sealed box; 2: high temperature growth furnace; 3: conveying device; 4: growth substrate; 5: sample delivery cylinder; 6: growth quartz tube; 7: sampling cylinder, 701: elastic hook, 7011: fixed plate, 7012: stop plate, 7013: movable hook plate, 7014: spring; 8: support seat; 9: cooling quartz tube; 10: plug valve; 11: vacuum pump one; 12: vacuum pump two; 13: diaphragm air inlet valve; 14: connecting quartz tube. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0033] In the description of the present invention, it should be understood that the terms "front", "rear", "left", "right", "up", "down", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying 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 direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0034] like Figures 1 to 4 As shown, the utility model provides a high-efficiency production device for single-walled carbon nanotubes, comprising a vacuum sealed box 1 and a high-temperature growth furnace 2.

[0035] The vacuum sealed box 1 is provided with a conveying device 3, and the growth substrate 4 is placed on the conveying device 3; a gate valve 10 is provided at the entrance of the vacuum sealed box 1; in this embodiment, the conveying device 3 is a conveyor belt driven by a motor. The growth substrate 4 is a quartz carrier loaded with catalyst particles; the catalyst particles are made by loading transition metals Fe, Co, etc. on the carrier, and the carrier is zeolite powder. The total content of the loaded metal catalyst accounts for 1%-10% of the mass of the catalyst particles. The conveyor belt is provided with a plurality of slots in which the quartz carrier is placed. In the present embodiment, the number of growth substrates placed on the conveyor belt at one time is designed to be 10 for continuous production. The vacuum sealed box 1 is also provided with a sample delivery cylinder 5 corresponding to the conveying device 3. The piston rod of the sample delivery cylinder 5 corresponds to the conveyor belt, and is used to push the quartz carrier loaded with catalyst particles on the conveyor belt. The vacuum sealed box 1 is connected with a vacuum pump 11 for extracting the gas in the vacuum sealed box 1, so as to ensure an inert environment when entering the growing quartz tube, and prepare for the negative pressure growth environment for growing the quartz tube in the next step.

[0036] The outlet of the vacuum sealed box 1 is also provided with a gate valve 10; the high temperature growth furnace 2 is provided with a growth quartz tube 6, and the growth quartz tube 6 is connected to the outlet of the vacuum sealed box 1 through a connecting quartz tube 14; specifically, one end of the connecting quartz tube 14 is connected to the gate valve 10 at the outlet of the vacuum sealed box 1, and the other end is connected to the growth quartz tube 6 through a connecting flange; the growth quartz tube 6 is also provided with a support seat 8 for supporting the growth substrate 4; the sample delivery cylinder 5 can push the growth substrate 4 onto the support seat 8 in the growth quartz tube 6; the growth quartz tube 6 is also connected to a carbon source supply system (not shown in the figure) and a vacuum pump 12. Specifically, the carbon source supply system includes a reducing gas supply pipeline, a protective gas supply pipeline, a carbon source gas supply pipeline and a mixing tank, and the reducing gas, the protective gas and the carbon source gas are mixed in the mixing tank and then passed into the growth quartz tube 6 through the pipeline. A diaphragm air inlet valve 13 is also provided on the pipeline for introducing the carbon source mixed gas into the growing quartz tube 6; the carbon source gas contains ethanol, and in addition to ethanol, it may also contain at least one of acetylene, ethylene, hexane, methane, propylene, butane and other hydrocarbons; the reducing gas or protective gas is selected from at least one of nitrogen, hydrogen, argon and helium. The vacuum pump 12 can evacuate the growing quartz tube 6 to 0.5-3Kpa, and can make the environment in the growing quartz tube a low negative pressure state, which can improve the purity and uniformity of the single carbon nanotubes and improve the quality of the single carbon nanotubes.

[0037] The production equipment also includes a sampling cylinder 7 and a cooling quartz tube 9, the inlet end of the cooling quartz tube 9 is connected to the outlet end of the growing quartz tube 6; the inlet end and the outlet end of the cooling quartz tube 9 are both connected to a plug valve; the cylinder body of the sampling cylinder 7 is fixed in the cooling quartz tube 9, and its piston rod can extend into the growing quartz tube 6. An elastic hook 701 is provided at the end of the piston rod of the sampling cylinder 7; specifically, the elastic hook 701 includes a fixed plate 7011 and a stopper plate 7012 fixed on the piston rod of the sampling cylinder 7, and a movable hook plate 7013 rotatably connected to the piston rod through a pin shaft, a spring 7014 is provided between the fixed plate 7011 and the stopper plate 7012, and the spring 7014 also passes through the stopper plate 7012 and is connected to the movable hook plate 7013. In the process of the piston rod of the sampling cylinder 7 extending into the growing quartz tube 6, the movable hook plate 7013 can be flipped upwards to facilitate the extension of the piston rod. When the piston rod of the sampling cylinder 7 is in place, the quartz carrier is hooked by the elastic hook 701 (the movable hook plate hooks against the edge of the quartz carrier) to hook the quartz carrier outward. During the hooking process, the movable hook plate 7013 will not flip due to the stopper of the stopper plate 7012, thereby realizing the action of hooking the quartz carrier.

[0038] After the growth substrate 4 carrying the grown single-walled carbon nanotubes is sent out of the high-temperature growth furnace 2, it is sent into the cooling quartz tube 9 for cooling. The cooling quartz tube 9 is also provided with a support seat 8 for supporting the growth substrate 4.

[0039] The production equipment of the utility model also includes a control device, which drives and controls the execution components in the production equipment through PLC to complete corresponding operations.

[0040] The method for producing single-walled carbon nanotubes using the above single-walled carbon nanotube high-efficiency production equipment comprises the following steps:

[0041] First, open the gate valve 10 at the entrance of the vacuum sealed box 1, and place the quartz carrier (growth substrate) loaded with catalyst particles on the card slot of the conveying device 3. 10 can be placed at a time. After the placement is completed, the control device controls the gate valve at the entrance of the vacuum sealed box 1 to close, and the vacuum pump 11 starts to work to extract the gas in the vacuum sealed box 1 so that the pressure gauge of the box itself shows a pressure below 30Pa.

[0042] After the conveying device 3 conveys the quartz carrier loaded with catalyst particles to the accurate position, the gate valve at the outlet of the vacuum sealed box 1 is opened, and the sample delivery cylinder is activated to deliver the quartz carrier loaded with catalyst particles into the growth quartz tube 6 in the high-temperature growth furnace 2; the sample delivery cylinder 5 is reset, and the gate valve at the outlet of the vacuum sealed box 1 is closed; the vacuum pump 12 starts to work, evacuates the growth quartz tube 6 to a negative pressure (0.5-3Kpa), and maintains rated power operation.

[0043] The diaphragm air inlet valve 13 is opened, and the carbon source mixed gas provided by the carbon source supply system is introduced into the growth quartz tube 6. Under the condition of high temperature heating, the carbon nanotubes grow on the growth substrate, and the growth time is 10-30 minutes, and the high temperature heating temperature during growth is 500-1000° C. During the growth process, the pumping speed of the vacuum pump 12 is 500-1000L / min. Under the cooperation of the diaphragm air inlet valve 13 and the vacuum pump 12, the upstream and downstream pressure difference in the growth quartz tube 6 is controlled at 0-0.3Kpa.

[0044] After the growth is completed, the gate valve 10 at the inlet end of the cooling quartz tube 9 is opened, and the sampling cylinder 7 sends the growth substrate carrying the single-walled carbon nanotube out of the high-temperature growth furnace 2, and then sends it into the cooling quartz tube 9 for cooling, and closes the gate valve at the inlet end of the cooling quartz tube 9; while cooling, the next growth substrate 4 is delivered to the position by the conveying device 3, and the above process is repeated. After a period of time, when the laser temperature measuring gun detects that the temperature of the quartz carrier carrying the single-walled carbon nanotube in the cooling quartz tube 9 is cooled to below 300°C, the gate valve at the outlet of the cooling quartz tube 9 is opened; the conveying device (such as a conveyor belt) connected to the outlet of the cooling quartz tube delivers the quartz carrier carrying the single-walled carbon nanotube, and then the grown single-walled carbon nanotube is collected and stored. Under the control of the control device, continue to work in a reciprocating cycle according to the sample cylinder sampling-growth-sampling cylinder sampling-product cooling-sampling storage until all the quartz carriers loaded with catalyst particles are used up.

[0045] If further growth is required, it is only necessary to put a quartz carrier loaded with catalyst particles on the conveying device 3, and the growth of carbon nanotube powder will continue until the operation program is manually terminated. Except for the manual participation of sample placement and material taking, the rest of the production equipment is completed by the corresponding execution components driven by the PLC (programmable logic controller), realizing the continuous and uninterrupted production of carbon nanotube powder materials, greatly saving time and labor costs; the production equipment can also be further enlarged according to actual conditions to achieve higher production efficiency.

[0046] The production equipment of the utility model can achieve a mass production rate of 1-100g / h single-walled carbon nanotubes. Figure 5 As shown, the single-walled carbon nanotubes produced by the present invention are relatively pure and uniform, and the diameter is about 1 to 2 nanometers (such as Figure 5 The single-walled carbon nanotubes (shown in (d)) are bundled, and there are no by-products such as amorphous carbon, multi-walled tubes MWCNT and nanoparticles. From the electron scanning microscopy SEM image ( Figure 5 As can be seen in (a), (b), and (c), single-walled carbon nanotube bundles with a thickness of about 10 nanometers are spider-web-like around zeolite particles of about 300 nanometers, without any other by-products.

[0047] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0048] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A single-walled carbon nanotube efficient production equipment, characterized in that: Including vacuum sealed box and high temperature growth furnace; The vacuum sealed box is provided with a conveying device, on which the growth substrate is placed; the vacuum sealed box is also provided with a sample delivery cylinder corresponding to the conveying device; The high temperature growth furnace is provided with a growth quartz tube, and the growth quartz tube is connected to the outlet of the vacuum sealed box; the sample delivery cylinder can deliver the growth substrate into the growth quartz tube; the growth quartz tube is also connected to a carbon source supply system; It also includes a sampling cylinder; the sampling cylinder is used to send the growth substrate carrying the grown single-walled carbon nanotubes out of the high-temperature growth furnace.

2. The high-efficiency production equipment for single-walled carbon nanotubes according to claim 1, characterized in that: The growth substrate is a quartz carrier loaded with catalyst particles.

3. The high-efficiency production equipment for single-walled carbon nanotubes according to claim 1, characterized in that: The conveying device is a conveyor belt, and the conveyor belt is driven by a motor.

4. The high-efficiency production equipment for single-walled carbon nanotubes according to claim 1, characterized in that: A plug valve is provided at the outlet of the vacuum sealed box and between the growing quartz tube and the cooling quartz tube.

5. The high-efficiency production equipment for single-walled carbon nanotubes according to claim 1, characterized in that: The vacuum sealed box is connected to a first vacuum pump, and the growth quartz tube is connected to a second vacuum pump.

6. The high-efficiency production equipment for single-walled carbon nanotubes according to claim 5, characterized in that: The pressure in the growth quartz tube is controlled to be 0.5-3Kpa.

7. The high-efficiency production equipment for single-walled carbon nanotubes according to claim 1, characterized in that: The piston rod of the sampling cylinder extends into the growing quartz tube, and an elastic hook is provided at the end thereof for hooking the growing substrate carrying the grown single-walled carbon nanotubes away from the growing quartz tube.

8. The high-efficiency production equipment for single-walled carbon nanotubes according to claim 1, characterized in that: The invention also comprises a cooling quartz tube, wherein the cooling quartz tube is connected to the growing quartz tube.

9. The high-efficiency production equipment for single-walled carbon nanotubes according to claim 8, characterized in that: The growth quartz tube and the cooling quartz tube are both provided with a support seat for supporting the growth substrate.

10. The high-efficiency production equipment for single-walled carbon nanotubes according to claim 1, characterized in that: The carbon source supply system is used to provide a carbon source mixed gas, which includes a reducing gas, a protective gas and a carbon source gas containing ethanol.

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