Carbon nanotube reactor and fluidized bed having the same

Abstract

The utility model relates to the field of carbon material production, concretely relates to a carbon nanotube reaction device and fluidized bed with the carbon nanotube reaction device, including the reaction jar and a plurality of carbon source supply nozzles, the lower end intercommunication of reaction jar has the gas delivery tank, the lower end intercommunication of gas delivery tank has the inert gas supply pipe, the inner diameter of gas delivery tank gradually reduces from top to bottom, the lateral wall of gas delivery tank is set up with a plurality of groups of gas hole rows from top to bottom, each group of gas hole rows includes a plurality of along the annular interval of gas delivery tank and set up the through -hole, and the carbon source supply nozzle is communicated with gas delivery tank through corresponding through -hole, and the axial direction of carbon source supply nozzle and the axial direction of gas delivery tank are perpendicular to each other, and the lateral wall of reaction jar is communicated with catalyst supply assembly. Through the coupling design of high pressure nozzle, the inner diameter of gas delivery tank gradually reduces from top to bottom and the inert gas supply pipe of gas delivery tank bottom, realizes the dynamic regulation and control of gas velocity, improves the utilization of carbon source and reduces the problem of catalyst agglomeration.

Description

Technical Field

[0001] This utility model relates to the field of carbon material production, specifically to a carbon nanotube reaction device and a fluidized bed having the carbon nanotube reaction device. Background Technology

[0002] Traditional fluidized bed preparation of carbon nanotubes faces the following technical bottlenecks: First, low carbon source utilization: In conventional fluidized beds, the carbon source gas is mixed with an inert carrier gas. Due to catalyst powder agglomeration and carbon nanotube coating, the contact efficiency between the active sites of the catalyst and the carbon source gas is insufficient, resulting in a carbon utilization rate of less than 30%. Second, catalyst agglomeration: Insufficient fluid dynamics lead to catalyst particle agglomeration, and carbon nanotube coating of active sites interrupts continuous growth. During catalyst growth, carbon nanotubes grow on the surface, and as the reaction time increases and the amount of growth increases, the carbon nanotubes will agglomerate on the catalyst surface. Catalyst agglomeration or carbon nanotube coating: Due to the adsorption force between micro and nano catalyst particles, agglomeration is very easy under insufficient gas fluidization, reducing the active sites of the catalyst. During growth, carbon nanotube coating of the catalyst surface reduces the contact between the carbon source gas and the active sites of the catalyst. This reduces the carbon source gas utilization rate and the carbon nanotube growth efficiency. Third, high-temperature environment limitation: The reaction temperature (500-1000℃) restricts the application of enhanced mixing methods such as mechanical stirring.

[0003] Existing improvements, such as multi-stage series fluidized beds and variable temperature control, still struggle to address the core issues of catalyst agglomeration and carbon source waste. For example, a carbon nanotube preparation apparatus and method (application number 202010547238.1) includes a fluidized reactor with a detachable heating assembly on its outer side, arranged parallel to the reactor body and moving horizontally. The upper outlet of the fluidized reactor is connected to a gas-solid separator, and the lower outlet is connected to a product discharge pipeline. However, this patented technology fails to effectively solve problems such as catalyst agglomeration, mutual agglomeration between the catalyst and surface-grown carbon nanotubes, and carbon nanotube agglomeration. Adsorption forces between catalyst particles persist at high temperatures, and agglomeration-induced reduction in active sites and insufficient carbon source contact continue to restrict reaction efficiency, resulting in significant carbon source waste. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this utility model is to provide a carbon nanotube reaction device with a simple structure. Through the coupling design of a high-pressure nozzle, a gas delivery tank with an inner diameter that gradually decreases from top to bottom, and an inert gas supply pipe at the bottom of the gas delivery tank, dynamic control of gas velocity can be achieved, thereby improving the utilization rate of carbon source and reducing the problem of catalyst agglomeration.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] This invention provides a carbon nanotube reaction device, including a reaction vessel and multiple carbon source supply nozzles. The lower end of the reaction vessel is connected to a gas delivery vessel, and the lower end of the gas delivery vessel is connected to an inert gas supply pipe. The inner diameter of the gas delivery vessel gradually decreases from top to bottom. Multiple sets of gas hole rows are opened from top to bottom on the side wall of the gas delivery vessel. Each set of gas hole rows includes multiple through holes arranged at annular intervals along the gas delivery vessel. The carbon source supply nozzles are connected to the gas delivery vessel through corresponding through holes. The axial direction of the carbon source supply nozzles is perpendicular to the axial direction of the gas delivery vessel. A catalyst supply assembly is connected to the side wall of the reaction vessel.

[0007] Furthermore, the upper end of the reaction vessel is connected to a buffer tank, and the upper end of the buffer tank is detachably connected to a cover, which is provided with an exhaust pipe connected to the cover.

[0008] Furthermore, the buffer tank includes an expanded diameter cavity and a straight cylinder communicating with the upper end of the expanded diameter cavity. The cover is detachably connected to the straight cylinder. The expanded diameter cavity is connected to the reaction tank. The inner diameter of the expanded diameter cavity gradually decreases from top to bottom.

[0009] Furthermore, an anti-clogging device is provided between the gas delivery tank and the inert gas supply pipe.

[0010] Furthermore, the anti-clogging device includes a horn cavity and a straight pipe connected to the upper end of the horn cavity. The lower end of the horn cavity is connected to an inert gas supply pipe, and the upper end of the straight pipe is connected to a gas delivery tank.

[0011] Furthermore, the catalyst supply assembly includes a delivery pipe and a storage tank connected to the upper end of the delivery pipe, the lower end of the delivery pipe being connected to a reaction tank, and the axial direction of the delivery pipe intersecting the axial direction of the reaction tank.

[0012] Furthermore, a control valve is provided between the delivery pipe and the storage tank.

[0013] Furthermore, the orifice diameter of the carbon source supply nozzle is 0.1-0.5 mm.

[0014] This invention also provides a fluidized bed, including the aforementioned carbon nanotube reaction device.

[0015] The beneficial effects of this invention are as follows: The carbon nanotube reaction device of this invention has a simple structure. It uses a ring-shaped array of carbon source supply nozzles to introduce carbon source gas. After being accelerated by the nozzles, the carbon source gas enters a gas delivery tank whose inner diameter gradually decreases from top to bottom. The carbon source gas flows laterally, forming a situation of gas flow convergence and collision. At the same time, an upward inert gas flow enters from the inert gas supply pipe, which converges with the carbon source gas to form irregular fluid movement, resulting in a turbulent flow field inside the reaction tank. Under this gas flow field, the catalyst will collide, making it difficult for the catalyst to agglomerate. Moreover, the grown carbon nanotubes will detach from the catalyst surface in time due to this collision. The active sites of the catalyst will not be deactivated by carbon nanotube coating or agglomeration, thereby extending the exposure time of the active center of the catalyst, increasing the growth rate, improving the utilization rate of carbon source, and reducing the problem of catalyst agglomeration. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a carbon nanotube reaction device.

[0017] The reference numerals in the figures include:

[0018] 1. Cover; 2. Exhaust pipe; 3. Buffer tank; 31. Expanded diameter cavity; 32. Straight cylinder; 4. Reaction vessel; 5. Gas delivery tank; 51. Carbon source supply nozzle; 6. Anti-clogging device; 61. Horn cavity; 62. Straight pipe; 7. Inert gas supply pipe; 8. Delivery pipe; 9. Storage tank; 10. Control valve. Detailed Implementation

[0019] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0020] like Figure 1 As shown, a carbon nanotube reaction device includes a reaction vessel 4 and multiple carbon source supply nozzles 51. The lower end of the reaction vessel 4 is connected to a gas delivery vessel 5, and the lower end of the gas delivery vessel 5 is connected to an inert gas supply pipe 7 for transporting inert gas. The inner diameter of the gas delivery vessel 5 gradually decreases from top to bottom. Multiple sets of gas hole rows are opened from top to bottom on the side wall of the gas delivery vessel 5. Each set of gas hole rows includes multiple through holes arranged at intervals along the annular shape of the gas delivery vessel 5. The carbon source supply nozzles 51 are connected to the gas delivery vessel 5 through corresponding through holes. The carbon source supply nozzles 51 are used to transport a mixture of carbon source gas (methane / ethylene) and carrier gas. The axial direction of the carbon source supply nozzles 51 is perpendicular to the axial direction of the gas delivery vessel 5. A catalyst supply assembly is connected to the side wall of the reaction vessel 4 for storing and transporting the catalyst into the reaction vessel 4.

[0021] The carbon nanotube reaction device of this invention has a simple structure. It adopts multiple sets of gas vents spaced apart from top to bottom. Each set of gas vents is equipped with carbon source supply nozzles 51 arranged in a ring array to introduce carbon source gas. After being accelerated by the nozzles, the carbon source gas enters the gas delivery tank 5, whose inner diameter gradually decreases from top to bottom. Since the axis of the carbon source supply nozzles 51 is perpendicular to the axis of the gas delivery tank 5, the carbon source gas is in lateral convection, which will form a situation of airflow convergence and collision. At the same time, the inert gas supply pipe 7 at the bottom of the gas delivery tank 5 has an upward inert gas flow, which converges with the carbon source gas to form an irregular fluid movement, so that a turbulent flow field is formed in the reaction tank 4. Under this airflow field, the catalyst will collide, making it difficult for the catalyst to agglomerate. The grown carbon nanotubes will detach from the catalyst surface in time due to this collision. The active sites of the catalyst will not be deactivated by carbon nanotube coating or agglomeration, thereby prolonging the exposure time of the active center of the catalyst, increasing the growth, improving the utilization rate of carbon source, and reducing the problem of catalyst agglomeration.

[0022] In this embodiment, the carbon source gas is accelerated by the carbon source supply nozzle 51 and enters the gas delivery tank 5, whose inner diameter gradually decreases from top to bottom. The flow velocity reaches 2-50 m / s, forming a turbulent flow field that impacts the catalyst, causing collisions between the catalysts and enhancing catalyst dispersion.

[0023] In this embodiment, the inner diameter of the exhaust pipe 2 can be set as needed, and the airflow velocity inside the exhaust pipe 2 is ≥ the "suspension velocity" of the carbon nanotubes (the minimum velocity at which particles can move with the airflow), which avoids the carbon nanotubes from settling and accumulating, while also allowing the carbon nanotubes to be discharged from the exhaust gas device.

[0024] Furthermore, the carbon source supply nozzle 51 has an orifice diameter of 0.1-0.5 mm, which facilitates the uniform distribution of carbon source gas and improves gas-solid contact efficiency.

[0025] Furthermore, the carbon nanotube reaction device also includes a heating and temperature control device, which is used to heat and control the temperature of the reaction vessel 4 to control the carbon source decomposition and carbon nanotube growth temperature.

[0026] Furthermore, the upper end of the reaction vessel 4 is connected to a buffer vessel 3, and the upper end of the buffer vessel 3 is detachably connected to a cover 1. The cover 1 is provided with an exhaust pipe 2 communicating with the cover 1. The buffer vessel 3 is used to allow the airflow to smoothly transition from the reaction vessel 4 to the exhaust pipe 2, reducing turbulence and indirectly ensuring the consistency of carbon nanotube growth. The cover 1 is detachably connected to the top of the buffer vessel 3, facilitating the cleaning of catalyst adhering to the buffer vessel 3 and the inner wall of the reaction vessel 4.

[0027] In this embodiment, when the present invention is used, the inert gas supply pipe 7 provides inert gases such as nitrogen or argon into the device, and after purging the air inside the device, the catalyst supply assembly stores and transports the catalyst to the reaction tank 4. Simultaneously, the carbon source supply nozzle 51 provides carbon source gas. The high pressure inside the nozzle allows the carbon source to diffuse rapidly and make full contact with the catalyst. The temperature inside the reaction tank 4 rises, the carbon source decomposes on the catalyst surface, and carbon atoms gradually deposit and grow into carbon nanotubes. Then, the carbon nanotubes are discharged from the exhaust pipe 2 with the gas flow. The exhaust pipe 2 is equipped with a filter device at its end to separate the exhaust gas from the carbon nanotubes.

[0028] Furthermore, the buffer tank 3 includes an expanded diameter cavity 31 and a straight cylinder 32 connected to the upper end of the expanded diameter cavity 31. The cover 1 is detachably connected to the straight cylinder 32. The expanded diameter cavity 31 is connected to the reaction tank 4, and the inner diameter of the expanded diameter cavity 31 gradually decreases from top to bottom. The expanded diameter cavity 31, with its "narrow inlet at the lower end and wide outlet at the upper end" structure, allows carbon nanotubes to smoothly enter the exhaust port from the reaction tank 4, avoiding the formation of turbulence that could lead to increased agglomeration or localized deposition of carbon nanotubes.

[0029] Furthermore, an anti-clogging device 6 is provided between the gas delivery tank 5 and the inert gas supply pipe 7. The anti-clogging device 6 is used to prevent the generated carbon nanotubes from settling and clogging the inert gas supply pipe 7. Moreover, the inert gas supply pipe 7 is purged by airflow, which can reduce the deposition of material at the outlet of the inert gas supply pipe 7.

[0030] Furthermore, the anti-clogging device 6 includes a horn cavity 61 and a straight pipe 62 connected to the upper end of the horn cavity 61. The lower end of the horn cavity 61 is connected to the inert gas supply pipe 7, and the upper end of the straight pipe 62 is connected to the gas delivery tank 5. The anti-clogging device 6, with its "narrow inlet at the lower end and wide outlet at the upper end" structure, increases the flow area and reduces the probability of clogging.

[0031] Furthermore, the catalyst supply assembly includes a delivery pipe 8 and a storage tank 9 connected to the upper end of the delivery pipe 8. The storage tank 9 is loaded with a catalyst (such as an iron, cobalt, or nickel-based catalyst, or a catalyst support). The lower end of the delivery pipe 8 is connected to the reaction tank 4. The axial direction of the delivery pipe 8 is intersected with the axial direction of the reaction tank 4, which facilitates the delivery of the catalyst into the reaction tank 4 by gravity and its dispersion in the reaction tank 4 by gravity or airflow, providing active sites for the growth of carbon nanotubes.

[0032] Furthermore, a control valve 10 is provided between the delivery pipe 8 and the storage tank 9. The control valve 10 is used to control the catalyst delivery rate.

[0033] This utility model also provides a fluidized bed for preparing carbon nanotubes, which includes the above-mentioned carbon nanotube reaction device and has the technical features and effects of the carbon nanotube reaction device, which will not be described in detail here.

[0034] The above description is only a preferred embodiment of this utility model. For those skilled in the art, there will be changes in the specific implementation method and application scope based on the idea of ​​this utility model. The content of this specification should not be construed as a limitation of this utility model.

Claims

1. A carbon nanotube reaction device, characterized in that: The reaction vessel (4) includes a reaction vessel (4) and multiple carbon source supply nozzles (51). The lower end of the reaction vessel (4) is connected to a gas delivery vessel (5), and the lower end of the gas delivery vessel (5) is connected to an inert gas supply pipe (7). The inner diameter of the gas delivery vessel (5) gradually decreases from top to bottom. Multiple sets of gas holes are opened on the side wall of the gas delivery vessel (5) from top to bottom. Each set of gas holes includes multiple through holes arranged at annular intervals along the gas delivery vessel (5). The carbon source supply nozzles (51) are connected to the gas delivery vessel (5) through corresponding through holes. The axial direction of the carbon source supply nozzles (51) is perpendicular to the axial direction of the gas delivery vessel (5). The side wall of the reaction vessel (4) is connected to a catalyst supply assembly.

2. The carbon nanotube reaction device according to claim 1, characterized in that: The upper end of the reaction vessel (4) is connected to a buffer tank (3), and the upper end of the buffer tank (3) is detachably connected to a cover (1). The cover (1) is provided with a tail gas pipe (2) connected to the cover (1).

3. The carbon nanotube reaction device according to claim 2, characterized in that: The buffer tank (3) includes an enlarged cavity (31) and a straight cylinder (32) connected to the upper end of the enlarged cavity (31). The cover (1) is detachably connected to the straight cylinder (32). The enlarged cavity (31) is connected to the reaction tank (4). The inner diameter of the enlarged cavity (31) gradually shortens from top to bottom.

4. The carbon nanotube reaction device according to claim 1, characterized in that: An anti-clogging device (6) is provided between the gas delivery tank (5) and the inert gas supply pipe (7).

5. The carbon nanotube reaction device according to claim 4, characterized in that: The anti-clogging device (6) includes a horn cavity (61) and a straight pipe (62) connected to the upper end of the horn cavity (61). The lower end of the horn cavity (61) is connected to an inert gas supply pipe (7), and the upper end of the straight pipe (62) is connected to a gas delivery tank (5).

6. The carbon nanotube reaction device according to claim 1, characterized in that: The catalyst supply assembly includes a delivery pipe (8) and a storage tank (9) connected to the upper end of the delivery pipe (8). The lower end of the delivery pipe (8) is connected to the reaction tank (4). The axial direction of the delivery pipe (8) is intersected with the axial direction of the reaction tank (4).

7. The carbon nanotube reaction device according to claim 6, characterized in that: A control valve (10) is provided between the delivery pipe (8) and the storage tank (9).

8. The carbon nanotube reaction device according to claim 1, characterized in that: The orifice diameter of the carbon source supply nozzle (51) is 0.1-0.5 mm.

9. A fluidized bed, characterized in that: The carbon nanotube reaction device according to any one of claims 1-8.

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