An apparatus for preparing single-walled carbon nanotubes by a floating catalyst chemical vapor deposition method

Abstract

The application relates to a device for preparing single-wall carbon nanotubes by a floating catalyst chemical vapor deposition method and belongs to the technical field of carbon nanotube material preparation. The application breaks through the reaction mode of a traditional liquid catalyst and completely replaces the reaction mode of the traditional liquid catalyst. On one hand, the solid catalyst can maintain a good morphology during the reaction and is not prone to aggregation. On the other hand, the solid catalyst can greatly adjust the catalyst concentration and the feeding speed, thereby significantly improving the yield of single-wall carbon nanotubes, saving the cost compared with the liquid catalyst, and being beneficial to adjusting the traditional cracking process into a catalyst preparation, a cracking process and the like, and optimizing the diversity of a production process.

Description

Technical Field

[0001] This invention relates to an apparatus for preparing single-walled carbon nanotubes by floating catalyst chemical vapor deposition, belonging to the field of carbon nanotube material preparation technology. Background Technology

[0002] With the development of the new energy industry, the market for power batteries and energy storage batteries is expanding rapidly, leading to a continuous increase in demand for carbon nanotubes. Compared to multi-walled carbon nanotubes, single-walled carbon nanotubes have more stable chemical properties, better conductivity, and higher mechanical properties, and are commonly used as conductive agents in high-end lithium-ion batteries. However, their price remains high due to limitations in production capacity and purity. Currently, the domestic method for producing single-walled carbon nanotubes is the floating catalyst chemical vapor deposition method, using a tube furnace with a diameter of 80-200mm.

[0003] This method currently uses a liquid catalyst (e.g., dissolved ferrocene) mixed with toluene and thiophene for the reaction. However, using a liquid catalyst presents the following problems:

[0004] 1. Difficulty in increasing feed rate: Because the active components formed after the gasification and decomposition of liquid catalyst are very easy to agglomerate, the activity of the catalyst itself will decrease significantly, resulting in the appearance of double-walled / multi-walled carbon nanotube impurities in the product, affecting product quality. The only way to solve this problem is to strictly control the concentration of liquid catalyst and the feed rate to a low and appropriate level, which limits production efficiency.

[0005] 2. Temperature is difficult to control: Different catalyst temperatures will affect the temperature requirements of different injection pump needles, and the temperature zone of the needle also needs to be adjusted when changing parameters such as catalyst concentration and feed rate. At the same time, due to the strong synergistic effect between different parameters, the temperature control process is extremely complex and difficult.

[0006] 3. High cost: Liquid catalysts are inherently expensive, and increasing production can only be achieved by increasing equipment and facility costs. This method of increasing production not only makes cost control difficult but also places high demands on equipment technology. Poor control of the uniformity of the furnace chamber, atmosphere, and liquid catalyst can negatively impact the quality of single-walled carbon nanotubes.

[0007] Furthermore, the equipment is prone to accidents and poses safety hazards.

[0008] In addition, problems such as product sticking to the wall and difficulty in collection often occur in actual production, resulting in poor production continuity and purity of single-walled carbon nanotubes. Summary of the Invention

[0009] To address the above problems, this invention provides an apparatus for preparing single-walled carbon nanotubes using a floating catalyst chemical vapor deposition method, comprising:

[0010] The feeding system includes an injection pump storing materials, a carrier gas generator storing and generating carrier gas, and a mixer connected to the injection pump and the carrier gas generator. The mixer has a first nozzle capable of thoroughly mixing the materials and combining them with the carrier gas before spraying them out through the first nozzle. The carrier gas is used to carry the reaction precursor into the corundum tube, preventing the reaction precursor from drifting to the upper part of the corundum tube due to lack of driving force.

[0011] The main reactor includes a control module and a heating furnace controlled and connected by the control module. The heating furnace contains a corundum tube connected to the first nozzle.

[0012] The purging device includes a rare gas generator that stores and generates rare gases, a second nozzle connected to the rare gas generator and leading to the wall of the corundum tube; and

[0013] The material collection system includes a water-cooled collection tank connected to the corundum tube, a collection box connected to the water-cooled collection tank, and an air pump connected to the collection box. The water-cooled collection tank has a cooling function. A first screen and a second screen are respectively provided inside the water-cooled collection tank and between the collection box and the air pump. The first screen is provided with multiple collection columns parallel to the corundum tube.

[0014] It should be understood that the terms "first" and "second" are only used to distinguish components with different positions or characteristics and have no other limiting meaning; the heating furnace can be a tubular furnace and can heat the corundum tube under the control of the control module, thereby causing the solid catalyst, carbon source and catalytic aid inside the corundum tube to undergo catalytic cracking reaction; the purging device sprays rare gas onto the tube wall of the corundum tube through the second nozzle, thereby blowing the carbon nanotube products on the tube wall of the corundum tube into the water-cooled collection tank of the collection system, effectively preventing the carbon nanotube products from sticking to the wall; the water-cooled collection tank is a tank container with cooling function, the first screen and multiple collection columns can be used to collect carbon nanotube products, and the collection columns can collect most of the continuous carbon nanotube products; while the second screen is used to collect fine carbon nanotube products.

[0015] In one embodiment of the present invention, the mixer is a vortex mixer, which can better mix the solid catalyst with the carbon source and catalyst aid; a preheater is provided between the carrier gas generating device and the mixer, which can preheat the carrier gas, thereby atomizing the liquid material and further improving the uniformity of the reaction precursor.

[0016] In one embodiment of the present invention, the corundum tube is connected to the first nozzle and the second nozzle by a flange.

[0017] Furthermore, the water-cooled collection tank includes an outer cavity, an inner cavity nested within the outer cavity, and a first screen installed in the inner cavity. The outer cavity is provided with an inlet and an outlet, and a water-cooling space is left between the outer cavity and the inner cavity. Cooling water can pass through the inlet, the water-cooling space, and the outlet in sequence to cool the first screen.

[0018] In one embodiment of the present invention, both the outer cavity and the inner cavity are provided with observation windows to facilitate observation of the collection status of the first sieve; the water-cooled collection tank is also provided with a pressure gauge and a safety valve to prevent excessive pressure in the water-cooled collection tank from damaging the equipment.

[0019] This invention also provides an application of an apparatus for preparing single-walled carbon nanotubes by floating catalyst chemical vapor deposition, comprising the following steps:

[0020] Step 1: Inject a mixture of toluene, solid catalyst and thiophene into the mixer using an injection pump, while a carrier gas generator supplies carrier gas into the mixer, so that the mixture and carrier gas combine to form a reaction precursor.

[0021] It should be understood that solid catalysts are less expensive than liquid catalysts, can maintain a better morphology during the reaction process, and are less prone to agglomeration; furthermore, adjusting the concentration of solid catalysts and the feed rate has less impact on the injection pump, and the process control is relatively simple.

[0022] Step 2: Inject the reaction precursor into the corundum tube through the first nozzle. Under the heating action of the furnace, the corundum tube undergoes a catalytic cracking reaction to generate the first carbon nanotube product. After the reaction is completed, use rare gas through the second nozzle to blow off the first carbon nanotube product from the tube wall.

[0023] Step 3: After the first carbon nanotube product is completely blown down into the first screen and / or the collection column of the first screen in the water-cooled collection tank, the first carbon nanotube product attached to the first screen and / or the collection column of the first screen is cooled to obtain the second carbon nanotube product.

[0024] Step 4: The second carbon nanotube product is continuously collected by pumping air into the collection box.

[0025] Preferably, the carrier gas provided in step 1 is hydrogen; the rare gas used in step 2 is argon.

[0026] The beneficial effects of this invention are:

[0027] This invention innovatively uses a solid catalyst to prepare carbon nanotubes, completely replacing the traditional liquid catalyst reaction mode. On the one hand, the solid catalyst can maintain a better morphology during the reaction and is less prone to agglomeration. On the other hand, the use of a solid catalyst allows for a significant adjustment of the catalyst concentration and feed rate, thereby significantly increasing the yield of single-walled carbon nanotubes. Moreover, it is more cost-effective than liquid catalysts, facilitating the transformation of traditional pyrolysis processes into catalyst preparation and pyrolysis processes, thus optimizing the diversity of production processes. In addition, by combining a carrier gas generator with a mixer, the solid catalyst can enter the corundum tube as a floating and dispersed reaction precursor, resulting in a more complete and uniform reaction. Furthermore, the combination structure of the first sieve and the collection column in the water-cooled collection tank ensures that the collected carbon nanotube products are more continuous and complete, which helps to solve the problems of production continuity and purity. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure in one embodiment of the present invention.

[0029] In the diagram, 1. Control module; 2. Heating furnace; 3. Corundum tube; 4. Injection pump; 5. Mixer; 6. Carrier gas generator; 7. Preheater; 8. First nozzle; 9. First flange; 10. Rare gas generator; 11. Second nozzle; 12. Second flange; 13. Water-cooled collection tank; 14. Outer cavity; 15. Inner cavity; 16. Inlet; 17. Outlet; 18. First screen; 19. Observation window; 20. Safety valve; 21. Pressure gauge; 22. Collection column; 23. Collection box; 24. Air pump; 25. Second screen. Detailed Implementation

[0030] Example 1

[0031] like Figure 1 As shown, this invention provides an apparatus for preparing single-walled carbon nanotubes by floating catalyst chemical vapor deposition, comprising:

[0032] The feeding system includes an injection pump 4 storing materials, a carrier gas generator 6 storing and generating carrier gas, and a mixer 5 connected to the injection pump 4 and the carrier gas generator 6. The mixer 5 has a first nozzle 8 that can fully mix the materials and combine them with the carrier gas before spraying them out through the first nozzle 8. The carrier gas generator 6 is a device capable of generating hydrogen gas, which serves as the carrier gas. A preheater 7 is provided between the carrier gas generator 6 and the mixer 5, and the preheater 7 can preheat the hydrogen gas.

[0033] The main reactor includes a control module 1 and a heating furnace 2 controlled and connected by the control module 1. The heating furnace 2 contains a corundum tube 3, which is connected to the first nozzle 8.

[0034] The purging device includes a rare gas generator 10 that stores and generates rare gases, a second nozzle 11 connected to the rare gas generator 10 and leading to the wall of the corundum tube 3, the corundum tube 3 being connected to the first nozzle 8 and the second nozzle 11 by a first flange 9; and

[0035] The material collection system includes a water-cooled collection tank 13 connected to the corundum tube 3 via a second flange 12, a collection box 23 connected to the water-cooled collection tank 13, and an air pump 24 connected to the collection box 23. The water-cooled collection tank 13 has a cooling function. A first screen 18 and a second screen 25 are respectively provided inside the water-cooled collection tank 13 and between the collection box 23 and the air pump 24. The first screen 18 is provided with a plurality of collection columns 22 parallel to the corundum tube 3.

[0036] Furthermore, the water-cooled collection tank 13 includes an outer cavity 14, an inner cavity 15 nested in the outer cavity 14, and a first screen 18 installed in the inner cavity. The outer cavity 14 is provided with an inlet 16 and an outlet 17. A water-cooling space is left between the outer cavity 14 and the inner cavity 15. Cooling water can pass through the inlet 16, the water-cooling space, and the outlet 17 in sequence to cool the first screen 18.

[0037] Both the outer cavity 14 and the inner cavity 15 are provided with observation windows 19 to facilitate observation of the collection status of the first sieve 18; the water-cooled collection tank 13 is also provided with a pressure gauge 21 and a safety valve 20 to prevent excessive pressure in the water-cooled collection tank 13 from damaging the equipment.

[0038] Example 2

[0039] The present invention also provides an application of the device in Embodiment 1, comprising the following steps:

[0040] Step 1: A mixture including toluene, solid catalyst and thiophene is injected into the mixer through injection pump 4, while hydrogen is supplied into the mixer as a carrier gas by carrier gas generator 6, so that the mixture and carrier gas combine to form a reaction precursor.

[0041] Step 2: Inject the reaction precursor into the corundum tube 3 through the first nozzle 8. Under the heating action of the heating furnace 2, the corundum tube 3 undergoes a catalytic cracking reaction to generate the first carbon nanotube product. After the reaction is completed, the first carbon nanotube product on the tube wall of the corundum tube 3 is blown off by rare gas through the second nozzle.

[0042] Step 3: After the first carbon nanotube product is completely blown down into the first sieve 18 and / or the collection column 22 of the first sieve 18 in the water-cooled collection tank 13, the first carbon nanotube product attached to the first sieve 18 and / or the collection column 22 of the first sieve 18 is cooled to obtain the second carbon nanotube product.

[0043] Step 4: The second carbon nanotube product is continuously collected by pumping air into the collection box 23 using the air pump 24.

[0044] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. An application of an apparatus for preparing single-walled carbon nanotubes by floating catalyst chemical vapor deposition, characterized in that, The apparatus for preparing single-walled carbon nanotubes by floating catalyst chemical vapor deposition includes: The feeding system includes an injection pump storing material, a carrier gas generator storing and capable of generating carrier gas, and a mixer connected to the injection pump and the carrier gas generator. The mixer is equipped with a first nozzle and is capable of fully mixing the material and combining it with the carrier gas before spraying it out through the first nozzle. The main reactor includes a control module and a heating furnace controlled and connected by the control module. The heating furnace contains a corundum tube connected to the first nozzle. The purging device includes a rare gas generator that stores and generates rare gases, a second nozzle connected to the rare gas generator and leading to the wall of the corundum tube; and The material collection system includes a water-cooled collection tank connected to the corundum tube, a collection box connected to the water-cooled collection tank, and an air pump connected to the collection box. The water-cooled collection tank has a cooling function. A first screen and a second screen are respectively provided inside the water-cooled collection tank and between the collection box and the air pump. The first screen is provided with multiple collection columns parallel to the corundum tube. The mixer is a vortex mixer; The water-cooled collection tank includes an outer cavity, an inner cavity nested in the outer cavity, and a first screen installed in the inner cavity. The outer cavity is provided with an inlet and an outlet. A water-cooling space is left between the outer cavity and the inner cavity. Cooling water can pass through the inlet, the water-cooling space, and the outlet in sequence to cool the first screen. A preheater is provided between the carrier gas generator and the mixer; The chemical vapor deposition method includes the following steps: Step 1: Inject a mixture of toluene, solid catalyst, and thiophene into the mixer using an injection pump, while a carrier gas generator supplies carrier gas into the mixer, allowing the mixture and carrier gas to combine and form a reaction precursor; by combining the carrier gas generator with the mixer, the solid catalyst can enter the corundum tube in the form of a floating and dispersed reaction precursor to undergo the reaction. Step 2: Inject the reaction precursor into the corundum tube through the first nozzle. Under the heating action of the furnace, the corundum tube undergoes a catalytic cracking reaction to generate the first carbon nanotube product. After the reaction is completed, use rare gas through the second nozzle to blow off the first carbon nanotube product from the tube wall. Step 3: After the first carbon nanotube product is completely blown down into the first screen and the collection column of the first screen in the water-cooled collection tank, the first carbon nanotube product attached to the first screen and the collection column of the first screen is cooled to obtain the second carbon nanotube product. Step 4: The second carbon nanotube product is continuously collected by pumping air into the collection box.

2. Use according to claim 1, characterized in that, The corundum tube is connected to the first nozzle and the second nozzle by a flange.

3. Use according to claim 1, characterized in that, Both the outer cavity and the inner cavity are provided with observation windows.

4. Use according to claim 1, characterized in that, The water-cooled collection tank is also equipped with a pressure gauge and a safety valve.

5. The use according to claim 1, characterized in that, The carrier gas provided in step 1 is hydrogen.

6. The use according to claim 1, characterized in that, The rare gas used in step 2 is argon.

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