CN1170020C - A method and special device for producing graphitized carbon fiber - Google Patents

Abstract

A method for producing graphitized carbon fibers is to first pass cooling water and working medium argon into the plasma generator; when the pressure P=0.3-0.5MPa, the plasma generator generates 2500 ° C ~ 3500 ° C when the current is 80-100A The high temperature in the local area of ℃, the carbon fiber passes through the plasma high temperature area, and the residence time is 10-20 seconds when passing, so as to obtain the graphitized carbon fiber. The invention has the advantages of simple process, low product cost, low energy consumption, thermal plasma can realize instant high temperature and fast rapid cooling, guarantee the comprehensive performance of materials, and the whole process is environment-friendly.

Description

A method and special device for producing graphitized carbon fiber

Technical field:

The invention belongs to a method for producing graphitized carbon fiber, and in particular relates to a production method and a special device for graphitizing carbon fiber in an oxygen-free environment by utilizing the characteristics of high temperature and high reactivity of thermal plasma.

Background technique:

As soon as carbon fiber came out, it was favored for its unique high strength, high modulus, ablation resistance, weavable, conductive and other excellent properties, and became a dazzling star in the material world. High modulus carbon (graphite) fiber is an important species in the carbon fiber family. It is the most important reinforcing material for advanced composite materials and has a wide range of uses in national defense construction and national economic construction. The carbon fiber is heated at 2000-3000°C under the condition of traction, so that the orientation degree of graphite crystallites in the fiber increases along the axis, the size increases, and the degree of perfection increases, that is, high-modulus graphite fibers are obtained. Graphite fiber is prepared by graphitization on the basis of carbon fiber. Therefore, the key to the development of graphite fiber is high-temperature technology and high-temperature equipment, that is, graphitization furnace. At present, the general graphitization process in the world adopts tubular graphitization furnace. This graphitization method is not only expensive in equipment cost, but also consumes a lot of energy and has low thermal efficiency.

content of the invention;

The purpose of the present invention is to provide a method and special device for preparing high-performance graphite fibers with simple process, low product cost and low energy consumption.

The method for preparing high-performance graphite fiber of the present invention comprises the steps:

1. First, the cooling water and the working medium argon are passed into the plasma generator;

2. When the pressure P=0.3-0.5MPa and the current is 80-100A, the plasma generator generates a high temperature in a local area of 2500 ℃ ~ 3500 ℃, and the room temperature is outside this area. The carbon fiber passes through the plasma high temperature area. The residence time is 10-20 seconds, so as to obtain graphitized carbon fibers.

In order to realize the above invention, a special device for the plasma generator is designed, which is connected by an insulating flange between the cathode and the anode; the cooling water pipe is connected with the anode. The anode and the reaction furnace are connected by a flange, and the argon inlet pipe is connected to the cathode

Compared with the prior art, the present invention has the following advantages: simple process, low product cost and low energy consumption. Thermal plasma can achieve instantaneous high temperature and rapid rapid cooling, which ensures the comprehensive performance of materials. Not only is the whole process environmentally friendly, but also the process parameters can be changed to control the degree of graphitization of the obtained carbon fiber.

Detailed ways:

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a longitudinal sectional structural diagram of a plasma reactor.

Example 1

As shown in the figure, the cathode 4 and the anode 3 are connected by an insulating flange 7, the cooling water pipe inlet 2 is connected to the anode 3 by welding, the anode 3 and the reaction furnace 1 are connected by a flange 8, and the argon gas inlet pipe 5 is connected to the cathode 4 connected. The cooling water is introduced from the inlet 2 of the cooling water pipe, and the argon gas is introduced through the argon gas inlet pipe 5, and a direct current of 80A is applied to the cathode 4 and the anode 3 at the same time at a pressure of 0.3 MPa, so that the gas is continuously discharged and an arc is formed. Pass through carbon fiber from reaction furnace 1, control the residence time of carbon fiber in the furnace to be 20 seconds. After the reaction, the tensile modulus was tested, and the results are listed in Table 1.

Example 2

Adjust the current to 90A, and the pressure in the reactor to 0.4MPa. Control the residence time of carbon fiber in the furnace to be 15 seconds. Others are carried out by the same method and conditions as in Example 1, and the tensile modulus is tested after the reaction, and these results are listed in Table 1.

Example 3

Adjust the current to 100A, and the pressure in the reaction furnace to 0.5MPa. Control the residence time of carbon fiber in the furnace to be 10 seconds. Others are carried out by the same method and conditions as in Example 1, and the tensile modulus is tested after the reaction, and these results are listed in Table 1.

Table 1 condition, result/case number Example 1 Example 2 Example 3 Pressure (MPa) 0.3 0.4 0.5 Residence time (s) 20 15 10 Current (A) 80 90 100 Tensile modulus (GPa) 377 382 390

It can be seen from the above table that the tensile modulus of the manufactured graphite fiber has reached the level of M40J (377GPa) by adopting the above-mentioned embodiment.

Claims (2)

1. a method of producing graphitized carbon fibre is characterized in that comprising the steps:

(1), at first cooling water and working media argon gas are fed plasma generator;

(2), when pressure P=0.3-0.5MPa, plasma generator produced the high temperature of 2500 ℃～3500 ℃ of regional areas when electric current was 80-100A, beyond this zone is room temperature, with carbon fiber by the plasma high-temperature district, by the time the time of staying be 10-20 second, thereby obtain graphitized carbon fibre.

2. a kind of device of producing graphitized carbon fibre as claimed in claim 1 is characterized in that it is by connecting by insulating flange (7) between negative electrode (4) and the anode (3); Cooling water pipe (2) links to each other with anode (3), connects with flange (8) between anode (3) and the reacting furnace (1), and argon gas ingress pipe (5) links to each other with negative electrode (4).

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