Method for producing Nano carbon tubes continuously and equipment

A carbon nanotube and catalyst technology, which is applied in the field of continuous production of carbon nanotubes, can solve the problems of serious overlap and adhesion between particles, clogging reactor production, and destroying the fluidized state, so as to ensure continuous operation and reduce back-mixing. degree, good separation effect

Active Publication Date: 2007-10-10
TSINGHUA UNIV
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Problems solved by technology

[0005] For the preparation of single/double-walled carbon nanotubes, the reaction conditions and operating conditions required for the nucleation and growth of the catalyst are also significantly different. In order to reduce the high concentration of H generated during the reaction 2 The side effects caused by the catalyst. The initial nucleation and growth process of single/double-walled carbon nanotubes requires a high space velocity carbon source gas flow rate, and in the later stage of growth, in order to improve the carbon source conversion rate, it is necessary to reduce the space velocity of the carbon source gas. The difference between high and low space velocities As high as 2 to 100 times, at this time the single reactor also showed obviou

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  • Method for producing Nano carbon tubes continuously and equipment
  • Method for producing Nano carbon tubes continuously and equipment
  • Method for producing Nano carbon tubes continuously and equipment

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Embodiment approach

[0031] The invention provides a method and device for continuous production of carbon nanotubes. The present invention adopts a device with multi-stage reactors connected in series, and by separately controlling the distribution and fluidization state of catalysts and carbon nanomaterials in the reactors at each stage, and operating in different regions, the normal fluidization of materials with a relatively large density span can be realized, ensuring The continuous operation is realized, and the high-efficiency conversion of raw materials and the high production capacity of the device are realized at the same time. The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0032] Figure 1 is a schematic diagram of a multi-stage serial fluidized bed reactor for the production of carbon nanotubes. In the figure, the first-stage main reactor 1, the second-stage main reactor 2, ... to the last-stage main reactor 3, are...

Embodiment 1

[0037] A single-stage reactor is used for the reaction, with an inner diameter of 500mm and a height of 2.5m. 1 kg of MWNT catalyst was loaded at one time, the operating gas velocity was 0.05 m / s, and the weight was 13 kg after 5 hours of reaction. It was found that the fluidization state of the solid material was poor and channeling occurred, resulting in a gas conversion rate of only 30%.

[0038] Three examples are given below to illustrate the application of multistage reactors.

[0039] (1) Adopt the device shown in Figure 1, the inner diameter of the second and second main reactors is respectively 200, 500mm, high 2.5m, one-time loading 1kg MWNT catalyst in the first-order main reactor, operating gas velocity 0.3m / s, the operating gas velocity of the second-stage main reactor is 0.05m / s, and no material is loaded. After reacting for 30 minutes, the volume expansion of the solid material in the first-stage main reactor was 250 times, the weight was 5 kg, the average yie...

Embodiment 2

[0043] Using the device shown in Figure 1, an alternating coil (magnetic field strength 1000A / m) is used to generate an alternating magnetic field at the outer wall of the main reactor of the first stage and the last stage. Since the catalyst contains iron particles, it is in the alternating magnetic field. It is constantly beating, which can obviously improve the fluidization quality.

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Abstract

This invention discloses high-efficiency method and apparatus for continuously producing carbon nanotubes. The apparatus is a multi-stage counter-current reaction apparatus. The method comprises: placing the catalyst in the pre-reactor or the main reactor, introducing mixed gases of H2 or CO, and N2 or Ar, reducing, then introducing raw material gas, reacting to obtain carbon nanotubes, and sending the expanded solid raw material to the next stage reactor for reaction. The gas flow and the solid raw material are arranged in counter-current contact mode in the reactors, which can increase the conversion rate of the solid raw material. This invention has such advantages as simple apparatus and easy operation, and is suitable for industrial production on the scale of tens of thousands of tons per year.

Description

technical field [0001] The invention belongs to the technical field of nano material preparation and chemical equipment. In particular, it relates to a high-efficiency continuous production method and device for carbon nanotubes using a multi-stage countercurrent reaction device. Background technique [0002] Under the concept of nano-agglomerated fluidization, the fluidized bed reactor was successfully used for large-scale preparation of carbon nanotubes (Wang Yao, et al. Agglomerated carbon nanotubes and its mass production in a fluidized-bed reactor. Physica B, 2002, 323:327-329). In view of the continuous increase in volume during the preparation of carbon nanotubes and the frequent movement of solid materials into and out of the reactor, a fluidized bed has great advantages over a fixed bed. [0003] The growth process of carbon nanotubes is a process of gradual volume expansion. As the reaction time prolongs, its reactivity gradually decreases, and the volume gradual...

Claims

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Application Information

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IPC IPC(8): C01B31/02
CPCC01B31/0233C01B2202/02C01B2202/04C01B2202/06B01J8/42B01J8/26B01J2219/182B01J2219/00033B82Y40/00Y10S977/843Y10S977/842B01J8/0055Y10S977/742B01J8/382B82Y30/00B01J8/006B01J8/28C01B31/024C01B32/162C01B32/164
Inventor 魏飞刘毅骞伟中罗国华
Owner TSINGHUA UNIV
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