WO2020253104A1

WO2020253104A1 - Carbon nano tube preparation device and method

Info

Publication number: WO2020253104A1
Application number: PCT/CN2019/120827
Authority: WO
Inventors: 陈名海; 袁鑫鑫; 阮超
Original assignee: 江西铜业技术研究院有限公司
Priority date: 2019-06-19
Filing date: 2019-11-26
Publication date: 2020-12-24
Also published as: KR20210016610A; JP2021533076A; CN110217777A; JP7178494B2; CN110217777B; KR102535679B1

Abstract

Provided are a nano carbon material, specially a carbon nano tube preparation device and method, which belong to the technical field of novel materials, wherein the device is formed by connecting a catalyst evaporation chamber (1), a chemical vapor deposition chamber (6) and a gas-solid separation chamber (7) in series, by using the high temperature and impact generated by an arc flame, a catalyst (4) in the catalyst evaporation chamber (1) is directly evaporated into an ultra-fine catalyst, which enters the chemical vapor deposition chamber (6) through a connection channel. Meanwhile, carrier gas and carbon source gas are respectively introduced by the catalyst evaporation chamber (1) and the chemical vapor deposition chamber (6), and the catalyst (4) reacts with a high-temperature cracked organic carbon source to generate a carbon nano tube, which is then separated and collected by the gas-solid separation device. The method can keep the catalyst generated by the arc high-temperature evaporation to enter a chemical vapor growth interval in an ultra-fine scale or even in an atomic state, have high activity and small scale, and is an effective way to prepare high-crystallinity single-walled carbon nano tubes. Moreover, the device is simple, can realize continuous preparation, and has a great industrialization value.

Description

Device and method for preparing carbon nanotube

Technical field

The invention belongs to the technical field of new materials, and relates to a nano carbon material, in particular to a carbon nano tube preparation device and method.

Background technique

Carbon nanotubes are tubular nanomaterials composed of sp ² hybrid carbon-carbon covalent bonds. They have a series of advantages such as light weight, high strength, high thermal conductivity, large surface area, and stable structure. They have been widely used since their birth. Attention, leading the hot spot of nano-material technology, has broad application prospects in the fields of structural composite materials, energy, catalysis and functional devices.

At present, the preparation methods of carbon nanotubes mainly include: chemical vapor deposition, arc ablation, laser, plasma, etc., of which chemical vapor deposition is a relatively mature process route and has been industrialized. However, due to the inherent low reaction temperature of the chemical vapor deposition method, the low degree of crystallization of carbon nanotubes caused by the chemical vapor deposition method results in a high defect content of carbon nanotubes prepared by the chemical vapor deposition method. Especially in the preparation of fine-diameter carbon nanotubes and single-walled carbon nanotubes, the surface defects are high, which causes their electrical conductivity to be greatly restricted and cannot be compared with carbon nanotubes prepared by high-temperature methods. Due to the low reaction temperature of the traditional chemical vapor deposition method, the carbon-carbon bonding barrier cannot be crossed well during the reconstruction process, and a large number of incomplete sp2 structures are often formed, causing internal defects in the carbon nanotubes, which seriously hinder electron transport. Reduce its conductivity. Therefore, increasing the catalyst activity or increasing the reaction temperature is a key element for the preparation of fine-diameter carbon nanotubes.

Chinese invention patent CN200710098478.2 discloses a method and device for the continuous production of carbon nanotubes, which adopts a multi-stage countercurrent reactor and utilizes a fluidized bed chemical vapor deposition process to achieve continuous production of carbon nanotubes. Chinese invention patent 201010234322.4 discloses a method for preparing single-walled carbon nanotubes with a controllable diameter, which uses a high-temperature arc ablation method to fill carbon powder and a metal catalyst into a carbon electrode, and prepare carbon nanotubes by direct ablation of the arc. Chinese invention patent 201110315452.5 discloses a method for preparing carbon nanotubes. A metal salt solution is loaded on a molybdenum or zirconium substrate and placed on a deposition table in the cavity of a DC plasma jet chemical vapor deposition equipment. The DC arc forms high temperature plasma The metal salt is used to decompose and reduce to generate a Ni/MgO catalyst, and then the hydrocarbon gas is passed in for high-temperature cracking to form carbon nanotubes. However, it is still a challenging task to realize the controllable preparation of the catalyst particle size and activity, so as to prepare fine-diameter carbon nanotubes and even single-wall carbon nanotubes.

Summary of the invention

The main purpose of the present invention is to provide a carbon nanotube preparation device and method to overcome the shortcomings in the prior art.

In order to achieve the aforementioned object of the invention, the technical solution adopted by the present invention is: a carbon nanotube preparation device, which includes a catalyst evaporation chamber, a chemical vapor deposition chamber, and a gas-solid separation chamber. The device passes the catalyst evaporation chamber through The pipeline chemical vapor deposition chamber is sealed and connected to realize the combination of high-temperature physical evaporation and chemical vapor deposition, so that the catalyst enters the chemical vapor deposition chamber directly through the connecting channel, and the gas path system separates the carrier gas and carbon source gas from the catalyst evaporation chamber and chemical vapor deposition chamber. The deposition chamber is opened to make the catalyst react with the high-temperature cracked organic carbon source to generate carbon nanotubes, which are then separated and collected through the gas-solid separation chamber.

Further, the structure of the carbon nanotube preparation device is as follows: the catalyst evaporation chamber, the chemical vapor deposition chamber and the gas-solid separation chamber are sealed and connected in sequence from left to right;

An organic carbon source mixed gas inlet is provided at the junction of the catalyst evaporation chamber and the chemical vapor deposition chamber; the other end of the catalyst evaporation chamber is provided with a carrier gas inlet and a high temperature evaporation spray gun;

The vacuum system is connected to the gas-solid separation chamber; the gas path system is connected to the organic carbon source mixed gas inlet and the carrier gas inlet respectively; the cooling system is arranged on the side wall of the chemical vapor deposition chamber, and the power supply system provides power supply.

Further: the catalyst evaporation chamber is a high-temperature physical evaporation method; the high-temperature physical evaporation method is a high-temperature arc, a high-temperature radio frequency plasma or a high-temperature microwave plasma; the catalyst evaporation chamber is a double-layer water-cooled stainless steel lined with a high-temperature heat insulation layer The shell is lined with a high temperature insulation layer made of porous ceramics, ceramic fiber felt, graphite or graphite felt.

Further: the chemical vapor deposition chamber is a quartz tube furnace.

Further: the separation method adopted in the gas-solid separation chamber is any one of centrifugal separation, cyclone separation and filtration separation.

Another object of the present invention is to provide a method for preparing carbon nanotubes by using the above-mentioned carbon nanotube preparation device. The method specifically includes the following steps:

S1) Put the catalyst in the catalyst evaporation chamber, start the vacuum system to exhaust the air in the catalyst evaporation chamber, start the gas path system to switch and pass the inert gas carrier gas;

S2) Turn on the chemical vapor deposition chamber to heat up and increase the temperature to the specified temperature;

S3) Then turn on the high-temperature evaporation spray gun to evaporate the catalyst in the catalyst evaporation chamber, and enter the chemical vapor deposition chamber with the carrier gas through the pipeline connection;

S4) Then the organic carbon source gas mixture is introduced into the chemical vapor deposition chamber, and the resulting product enters the gas-solid separation chamber with the carrier gas through the connecting pipe, and the final product is obtained after separation.

Further: the catalyst in S1) is a metal catalyst, and the metal catalyst includes any one or more of iron, cobalt, and nickel; and the carrier gas is any one of nitrogen, argon, and helium.

Further: the temperature in S2) is 500-1500°C.

Further: the maximum temperature of the high-temperature evaporation spray gun in S3) is >2000°C, and the power is >10kW.

Further: the organic carbon source gas mixture in S4) includes organic carbon source gas, inert carrier gas and hydrogen; wherein the volume of the organic carbon source gas is 5-80%; the volume of hydrogen is 0.1-10%, and the rest It is an inert carrier gas.

Further: the organic carbon source gas is one or more of methane, ethane, ethylene, ethanol, and methanol.

Compared with the prior art, the advantages of the present invention include:

(1) The use of a high-temperature physical evaporation process combined with a chemical vapor deposition device enables continuous catalyst preparation and carbon nanotube growth, effectively ensuring the activity of the catalyst, and avoiding catalyst failure caused by oxidation and aggregation of the intermittently prepared catalyst, which is beneficial Improve the catalytic efficiency of subsequent chemical vapor deposition;

(2) The catalyst is prepared by high-temperature physical evaporation process, so that the metal is directly evaporated in a gaseous state, and ultra-fine-scale catalyst particles can be obtained, which is beneficial to the effective preparation of ultra-fine diameter carbon nanotubes and even single-walled carbon nanotubes;

(3) The whole set of equipment integrates catalyst preparation, carbon nanotube preparation and separation and collection functions, which can realize continuous preparation, and has the characteristics of high production efficiency and simple process.

Description of the drawings

Fig. 1 is a schematic structural diagram of a carbon nanotube preparation device of the present invention.

2 is a schematic diagram of a scanning electron microscope of the carbon nanotube product prepared in Example 1 of the method of the present invention.

3 is a schematic diagram of a scanning electron microscope of a carbon nanotube product prepared in Example 2 of the method of the present invention.

In the figure:

1. Catalyst evaporation chamber; 2. Carrier gas inlet; 3. High temperature evaporation spray gun; 4. Catalyst; 5. Organic carbon source mixed gas inlet; 6. Chemical vapor deposition chamber; 7. Gas-solid separation chamber.

Detailed ways

The technical solution of the present invention will be further described below in conjunction with the drawings and specific embodiments.

As shown in Figure 1, a carbon nanotube preparation device of the present invention includes a catalyst evaporation chamber, a chemical vapor deposition chamber, and a gas-solid separation chamber. The device seals the catalyst evaporation chamber through a pipeline chemical vapor deposition chamber. Connected to realize the combined use of high-temperature physical evaporation and chemical vapor deposition, so that the catalyst directly enters the chemical vapor deposition chamber through the connecting channel, and the gas path system passes the carrier gas and carbon source gas into the catalyst evaporation chamber and the chemical vapor deposition chamber respectively, so that The catalyst reacts with the high-temperature cracked organic carbon source to generate carbon nanotubes, which are then separated and collected through a gas-solid separation chamber.

Further: the chemical vapor deposition chamber is a quartz tube furnace.

Another object of the present invention is to provide a process method for preparing carbon nanotubes by using the above-mentioned carbon nanotube preparation device. The method specifically includes the following steps:

Further: the temperature in S2) is 500-1500°C.

Example 1

The carbon nanotube preparation device consists of a catalyst evaporation chamber, a chemical vapor deposition chamber, and a gas-solid separation chamber in series. The catalyst evaporation chamber is a high-temperature arc device with a power of 20kW. The outer layer is made of a double-layer water-cooled stainless steel shell lined with a graphite high-temperature heat insulation layer Composition; the chemical vapor deposition chamber is a quartz tube furnace; the gas-solid separation chamber is a cyclone separation device. With iron as the metal catalyst, the catalyst is first placed in the catalyst evaporation chamber, and after evacuating to remove air, the inert gas carrier gas helium is switched. At the same time, the chemical vapor deposition chamber is heated to 1200° C., and then the high-temperature arc generated by the arc device is turned on to vaporize the iron atoms and the carrier gas helium gas is passed into the chemical vapor deposition chamber through the pipeline. The temperature of the chemical vapor deposition chamber is controlled at 1200°C, and the organic carbon source mixed gas is methane (45%), helium (50%) and hydrogen (5%), which are injected into the chemical vapor deposition chamber through the organic carbon source mixed gas inlet. The carbon source is catalytically cracked to grow carbon nanotubes at a high temperature, and the back end is connected to a cyclone separation device for gas-solid separation to achieve continuous preparation and collection, and the morphology of the carbon nanotube product scanned by an electron microscope is obtained (as shown in Figure 2).

Example 2

The carbon nanotube preparation device consists of a catalyst evaporation chamber, a chemical vapor deposition chamber and a gas-solid separation chamber in series. The catalyst evaporation chamber is a high-temperature radio frequency plasma with a power of 25kW. The outer layer is made of double-layer water-cooled stainless steel lined with a porous ceramic high-temperature insulation layer The shell is composed; the chemical vapor deposition chamber is a quartz tube furnace; the gas-solid separation chamber is a cyclone separation device. Using iron as the metal catalyst, first put the catalyst in the catalyst evaporation chamber, evacuating vacuum to remove air, then switch to inert gas carrier gas argon. At the same time, the chemical vapor deposition chamber is heated to 1300°C, and then the high-temperature arc generated by the arc device is turned on to vaporize the iron atoms and then the carrier gas argon gas is passed into the chemical vapor deposition chamber through the pipeline. The temperature of the chemical vapor deposition chamber is controlled at 1300°C, and the organic carbon source mixed gas is ethylene (5%), argon (85%) and hydrogen (10%), which are injected into the chemical vapor deposition chamber through the organic carbon source mixed gas inlet. The carbon source is catalytically cracked to grow carbon nanotubes at high temperature, and the back end is connected to a cyclone separation device for gas-solid separation to achieve continuous preparation and collection, and the morphology of the carbon nanotube product through electron microscope scanning is obtained (as shown in Figure 3)

Example 3

The carbon nanotube preparation device consists of a catalyst evaporation chamber, a chemical vapor deposition chamber, and a gas-solid separation chamber in series. The catalyst evaporation chamber is a high-temperature microwave plasma with a power of 25kW. The outer layer is double-layer water-cooled with a ceramic fiber felt high-temperature insulation layer. It is composed of a stainless steel shell; the chemical vapor deposition chamber is a quartz tube furnace; the gas-solid separation chamber is a cyclone separation device. With iron as the metal catalyst, the catalyst is first placed in the catalyst evaporation chamber, and after evacuating to remove air, the inert gas carrier gas helium is switched. At the same time, the chemical vapor deposition chamber is heated to 500° C., and then the high-temperature arc generated by the arc device is turned on to vaporize the iron atoms and pass the carrier gas helium into the chemical vapor deposition chamber through the pipeline. The temperature of the chemical vapor deposition chamber is controlled at 500°C, and the organic carbon source mixed gas is methanol (80%), nitrogen (15%) and hydrogen (5%), which are injected into the chemical vapor deposition chamber through the organic carbon source mixed gas inlet. The carbon source is catalytically cracked to grow carbon nanotubes under high temperature, and the back end is connected with a cyclone separation device for gas-solid separation to realize continuous preparation and collection.

Example 4

The carbon nanotube preparation device consists of a catalyst evaporation chamber, a chemical vapor deposition chamber, and a gas-solid separation chamber in series. The catalyst evaporation chamber is a high-temperature arc device with a power of 20kW. The outer layer is made of a double-layer water-cooled stainless steel shell lined with a graphite high-temperature heat insulation layer Composition; the chemical vapor deposition chamber is a quartz tube furnace; the gas-solid separation chamber is a cyclone separation device. With iron as the metal catalyst, the catalyst is first placed in the catalyst evaporation chamber, and after evacuating to remove air, the inert gas carrier gas helium is switched. At the same time, the chemical vapor deposition chamber is heated to 1500° C., and then the high-temperature arc generated by the arc device is turned on to vaporize the iron atoms and the carrier gas helium is passed into the chemical vapor deposition chamber through the pipeline. The temperature of the chemical vapor deposition chamber is controlled at 1500°C, and the organic carbon source mixture is ethanol (45%), helium (54.9%) and hydrogen (0.1%), which are injected into the chemical vapor deposition chamber through the organic carbon source mixture inlet. The carbon source is catalytically cracked to grow carbon nanotubes under high temperature, and the back end is connected with a cyclone separation device for gas-solid separation to realize continuous preparation and collection.

Example 5

The carbon nanotube preparation device consists of a catalyst evaporation chamber, a chemical vapor deposition chamber and a gas-solid separation chamber in series. The catalyst evaporation chamber is a high-temperature arc device with a power of 20kW. The outer layer is made of a double-layer water-cooled stainless steel shell lined with a graphite high-temperature heat insulation layer Composition; the chemical vapor deposition chamber is a quartz tube furnace; the gas-solid separation chamber is a cyclone separation device. With cobalt as the metal catalyst, the catalyst is first placed in the catalyst evaporation chamber, after vacuuming to remove air, the inert gas carrier gas helium is switched. At the same time, the chemical vapor deposition chamber is heated to 1200° C., and then the high-temperature arc generated by the arc device is turned on to vaporize the iron atoms and the carrier gas helium gas is passed into the chemical vapor deposition chamber through the pipeline. The temperature of the chemical vapor deposition chamber is controlled at 1200°C, and the organic carbon source mixture is ethane (45%), helium (45%) and hydrogen (5%), which are injected into the chemical vapor deposition chamber through the organic carbon source mixture inlet. The carbon source is catalytically cracked to grow carbon nanotubes under high temperature, and the back end is connected with a filter device for gas-solid separation to realize continuous preparation and collection.

Example 6

The carbon nanotube preparation device consists of a catalyst evaporation chamber, a chemical vapor deposition chamber and a gas-solid separation chamber in series. The catalyst evaporation chamber is a high-temperature arc device with a power of 50kW. The outer layer is made of a double-layer water-cooled stainless steel shell lined with a graphite high-temperature heat insulation layer Composition; the chemical vapor deposition chamber is a quartz tube furnace; the gas-solid separation chamber is a cyclone separation device. When nickel is used as a metal catalyst, the catalyst is first placed in the catalyst evaporation chamber, and after vacuuming to remove air, the inert gas carrier gas helium is switched. At the same time, the chemical vapor deposition chamber is heated to 1200° C., and then the high-temperature arc generated by the arc device is turned on to vaporize the iron atoms and the carrier gas helium gas is passed into the chemical vapor deposition chamber through the pipeline. The temperature of the chemical vapor deposition chamber is controlled at 1200°C, and the organic carbon source mixture is methane (45%), helium (45%) and hydrogen (5%), which are injected into the chemical vapor deposition chamber through the organic carbon source mixture inlet. The carbon source is catalytically cracked to grow carbon nanotubes at high temperature, and the back end is connected with a cyclone separation device for gas-solid separation to realize continuous preparation and collection.

Example 7

The carbon nanotube preparation device consists of a catalyst evaporation chamber, a chemical vapor deposition chamber and a gas-solid separation chamber in series. The catalyst evaporation chamber is a high-temperature arc device with a power of 50kW. The outer layer is made of a double-layer water-cooled stainless steel shell lined with a graphite high-temperature heat insulation layer Composition; the chemical vapor deposition chamber is a quartz tube furnace; the gas-solid separation chamber is a cyclone separation device. Using iron and cobalt as metal catalysts, the catalyst is first placed in the catalyst evaporation chamber, and after vacuuming to remove air, the inert gas carrier gas helium is switched. At the same time, the chemical vapor deposition chamber is heated to 1200°C, and then the high-temperature arc generated by the arc device is turned on to vaporize the iron atoms and the carrier gas helium is passed into the chemical vapor deposition chamber through the pipeline. The temperature of the chemical vapor deposition chamber is controlled at 1200°C, and the organic carbon source mixture is methane (45%), helium (45%) and hydrogen (5%), which are injected into the chemical vapor deposition chamber through the organic carbon source mixture inlet. The carbon source is catalytically cracked to grow carbon nanotubes under high temperature, and the back end is connected with a cyclone separation device for gas-solid separation to realize continuous preparation and collection.

In view of the deficiencies in the prior art, the inventor of the present case has been able to propose the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principles will be further explained as follows.

Claims

A carbon nanotube preparation device. The carbon nanotube preparation device includes a catalyst evaporation chamber, a chemical vapor deposition chamber, and a gas-solid separation chamber. The device is characterized in that the device seals the catalyst evaporation chamber through the pipeline chemical vapor deposition chamber to achieve high temperature. Physical evaporation and chemical vapor deposition are combined to make the catalyst directly enter the chemical vapor deposition chamber through the connecting channel. At the same time, the gas path system passes the carrier gas and carbon source gas into the catalyst vaporization chamber and the chemical vapor deposition chamber respectively to make the catalyst and high temperature cracking The organic carbon source reacts to produce carbon nanotubes, which are then separated and collected through the gas-solid separation chamber.
The carbon nanotube preparation device according to claim 1, wherein the structure of the carbon nanotube preparation device is: the catalyst evaporation chamber, the chemical vapor deposition chamber, and the gas-solid separation chamber are sealed and connected in sequence from left to right;

An organic carbon source mixed gas inlet is provided at the junction of the catalyst evaporation chamber and the chemical vapor deposition chamber; the other end of the catalyst evaporation chamber is provided with a carrier gas inlet and a high temperature evaporation spray gun;

The vacuum system is connected to the gas-solid separation chamber; the gas path system is connected to the organic carbon source mixed gas inlet and the carrier gas inlet respectively; the cooling system is arranged on the side wall of the chemical vapor deposition chamber, and the power supply system provides power supply.
The carbon nanotube preparation device according to claim 2, wherein the catalyst evaporation chamber is a high-temperature physical evaporation method; the high-temperature physical evaporation method is a high-temperature arc, a high-temperature radio frequency plasma, or a high-temperature microwave plasma; The catalyst evaporation chamber is a double-layer water-cooled stainless steel shell lined with a high-temperature heat insulation layer, and the high-temperature heat insulation layer is lined with porous ceramics, ceramic fiber felt, graphite or graphite felt.
The device according to claim 2, wherein the chemical vapor deposition chamber is a quartz tube furnace; the separation method used in the gas-solid separation chamber is any one of centrifugal separation, cyclone separation and filtration separation .
A method for preparing carbon nanotubes by using the carbon nanotube preparation device according to any one of claims 1 to 4, wherein the method specifically includes the following steps:

S1) Put the catalyst in the catalyst evaporation chamber, start the vacuum system to exhaust the air in the catalyst evaporation chamber, start the gas path system to switch and pass the inert gas carrier gas;

S2) Turn on the chemical vapor deposition chamber to heat up and increase the temperature to the specified temperature;

S3) Then turn on the high-temperature evaporation spray gun to evaporate the catalyst in the catalyst evaporation chamber, and enter the chemical vapor deposition chamber with the carrier gas through the pipeline connection;

S4) Then, the organic carbon source gas mixture is introduced into the chemical vapor deposition chamber, and the resulting product enters the gas-solid separation chamber with the carrier gas through the connecting pipe, and the final product is obtained after separation.
The method according to claim 5, wherein the catalyst in S1) is a metal catalyst, and the metal catalyst includes any one or more of iron, cobalt, and nickel; and the carrier gas is nitrogen or argon. And helium.
The method according to claim 5, wherein the temperature in S2) is 500-1500°C.
The method according to claim 5, characterized in that the highest temperature of the high-temperature evaporation spray gun in S3) is >2000°C and the power is >10kW.
The method according to claim 5, wherein the organic carbon source gas mixture in S4) includes organic carbon source gas, inert carrier gas and hydrogen; wherein the volume of the organic carbon source gas is 5-80 %; The volume of hydrogen is 0.1-10%, and the rest is inert carrier gas.
The method according to claim 9, wherein the organic carbon source gas is one or more of methane, ethane, ethylene, ethanol, and methanol.