CN210657241U

CN210657241U - Thermal stabilization device for carbon fiber production

Info

Publication number: CN210657241U
Application number: CN201921554886.9U
Authority: CN
Inventors: 孙兴祥; 孔令强; 陈文书; 孙春根; 郭建军; 傅春盛; 李飞
Original assignee: Zhejiang Jingye Xinxing Material Co ltd; Zhejiang Jinggong Carbon Fiber Co ltd
Current assignee: Zhejiang Baojing Carbon Material Co ltd
Priority date: 2019-09-19
Filing date: 2019-09-19
Publication date: 2020-06-02
Anticipated expiration: 2029-09-19

Abstract

The utility model relates to a thermal stabilization device for carbon fiber production, thermal stabilization device can constitute by 3-8 group's furnaces, and the fibre silk bundle loops through every oxidation furnace to limited reciprocating motion in the stove, according to fibre traffic direction, the furnace temperature setting risees in proper order. The utility model discloses a key feature is to adopt the nitrogen gas medium in thermostabilization later stage to reach the purpose of control oxygen content, simultaneously under thermostabilization later stage temperature, the cyclization reaction takes place as usual, has solved the equilibrium between the in-process cyclization degree of thermostabilization and the oxygen content, is favorable to the carbon yield to improve and the defect production of minimizing.

Description

Thermal stabilization device for carbon fiber production

Technical Field

The utility model belongs to the technical field of the carbon fiber equipment technique and specifically relates to a thermostabilization device is used in carbon fiber production.

Background

Polyacrylonitrile (PAN) based carbon fiber is an artificial synthetic fiber, which is a fibrous polymer obtained by a series of processes such as polymerization, spinning, pre-oxidation and carbonization of acrylonitrile and itaconic acid or other comonomers. The polyacrylonitrile-based carbon fiber has a series of excellent properties such as high specific strength, high specific modulus, high temperature resistance, chemical corrosion resistance, fatigue resistance, heat resistance, impact resistance, radiation resistance, easy conductivity, heat transfer, small specific gravity and the like, and belongs to typical high-performance fibers. The manufacturing of carbon fiber involves three stages of polymerization, spinning and carbonization, the carbonization process is a process for gradually removing non-carbon elements from polyacrylonitrile continuous fiber at different temperatures, the key processes mainly comprise pre-oxidation (thermal stabilization), low-temperature carbonization and high-temperature carbonization, and the thermal stabilization process of PAN fiber is one of the key steps for determining the performance of carbon fiber and has been the hotspot of the preparation research of PAN-based carbon fiber. Through thermal stabilization treatment, linear PAN molecules are converted into a cross-linked ladder-shaped structure, and the structure can enable a precursor to be subjected to a high-temperature carbonization reaction process, and finally, non-carbon elements are removed to prepare the carbon fiber.

The main reactions that occur during thermal stabilization include: initiation of a comonomer, cyanocyclization of an imine polymer for forming a ladder structure, and bonding of carbon and oxygen atoms in PAN fibers to form an oxygen-containing group. Meanwhile, in the heat stabilization process of the PAN fiber, oxygen molecules permeate from the surface layer of the fiber to the inside, and byproducts generated by the reaction diffuse from the inside to the outside of the fiber, so the mass transfer process of the PAN fiber is a double diffusion process, and the bonding reaction of oxygen has a direct relation with the heat stabilization temperature and time. However, oxygen is removed in the form of CO, CO2, etc. during the subsequent high and low temperature carbonization process, which not only causes carbon loss, but also causes certain defects in the fiber or on the surface of the fiber due to too high oxygen content, resulting in reduced mechanical properties or broken filaments. Therefore, in the research and production processes, it is desirable to promote the thermal stabilization of oxygen to some extent, but the oxygen content is controlled to a certain extent as much as possible while ensuring the maximum degree of cyclization reaction.

In the heat stabilization process of the PAN fiber, under the condition of certain equipment, the adjustment of a gradient temperature spectrum is mainly used as a main control means in experimental research and industrial production, the temperature is usually controlled to be 200-300 ℃, a medium is air, an oxidation reaction and a cyclization reaction are sensitive to the heat stabilization temperature, and the cyclization degree and the oxygen content in the PAN fiber are higher as the temperature is higher. How to balance the occurrence ratio of the oxidation reaction and the cyclization reaction in the thermal stabilization process becomes a more innovative research topic for preparing high-quality carbon fibers. Although there are also related patents that mention different media taken during the thermal stabilization, there are clear differences in the purpose and embodiments of the patents.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the defects of the prior art and provide a thermal stabilization device for carbon fiber production; the method can solve the problem that the cyclization degree is improved but the oxygen content is controlled in the PAN fiber, and can improve the comprehensive quality of the carbon fiber to a certain extent.

The purpose of the utility model is realized through the following technical scheme:

a thermal stabilization device for carbon fiber production is sequentially provided with a No. 1 oxidation furnace, a No. 2 oxidation furnace, a No. 3 oxidation furnace, a No. 4 oxidation furnace, a No. 5 oxidation furnace, a No. 6 oxidation furnace, a low-temperature carbonization furnace and a high-temperature carbonization furnace; are connected in sequence through pipelines.

The No. 1 oxidation furnace, the No. 2 oxidation furnace, the No. 3 oxidation furnace and the No. 4 oxidation furnace use air as a medium.

The No. 5 and No. 6 oxidation furnaces take nitrogen as a medium or the No. 1-5 oxidation furnace takes air as a medium.

The No. 6 oxidation furnace uses nitrogen as a medium.

In order to achieve the purpose of controlling the cyclization degree and the oxygen content balance in the PAN fiber, the heat stabilizing device is required to be used for realizing the purpose, the heat stabilizing device can consist of 3-8 groups of furnaces, fiber tows sequentially pass through each oxidation furnace and run in the furnaces in a limited reciprocating mode, and the furnace temperature is set to rise sequentially according to the running direction of the fiber. Taking 6 groups of oxidation furnaces as an example (see a schematic diagram), in the carbonization process, fiber tows sequentially pass through a No. 1-6 oxidation furnace, and after coming out of the No. 6 oxidation furnace, the fiber tows are carbonized at low temperature and high temperature to complete the carbonization process. In the heat stabilization process, the oxidation reaction is mainly concentrated in a high-temperature area, the No. 1-4 oxidation furnace takes air as a medium, the No. 5 and No. 6 oxidation furnaces take nitrogen as a medium or the No. 1-5 oxidation furnace takes air as a medium, and the No. 6 oxidation furnace takes nitrogen as a medium.

Compared with the prior art, the utility model has the positive effects that:

the utility model discloses a key feature is to adopt the nitrogen gas medium in thermostabilization later stage to reach the purpose of control oxygen content, simultaneously under thermostabilization later stage temperature, the cyclization reaction takes place as usual, has solved the equilibrium between the in-process cyclization degree of thermostabilization and the oxygen content, is favorable to the carbon yield to improve and the defect production of minimizing.

Drawings

FIG. 1 is a schematic diagram of a key process of a PAN fiber carbonization process

The labels in the figures are:

1. a fiber tow;

2. 1# oxidation furnace;

3. 2# oxidation furnace;

4. 3# oxidation furnace;

5. 4# oxidation furnace;

6. 5# oxidizing furnace;

7. 6# oxidation furnace;

8. a low-temperature carbonization furnace;

9. a high-temperature carbonization furnace.

Detailed Description

The following provides a specific embodiment of the thermal stabilization device for carbon fiber production of the present invention.

Example 1

A novel thermal stabilization process treatment method for carbon fiber production is realized by an oxidation furnace and a high-low temperature carbonization furnace for carbon fiber production, and comprises a fiber tow 1, a No. 1 oxidation furnace 2, a No. 2 oxidation furnace 3, a No. 3 oxidation furnace 4, a No. 4 oxidation furnace 5, a No. 5 oxidation furnace 6, a No. 6 oxidation furnace 7, a low-temperature carbonization furnace 8 and a high-temperature carbonization furnace 9.

In the implementation process, the temperature settings of the 1# -6# oxidation furnace are respectively as follows: the heating medium of the No. 1-5 oxidation furnace is air at 210 ℃, 230 ℃, 237 ℃, 243 ℃, 255 ℃ and 260 ℃, and the heating medium of the No. 6 oxidation furnace is nitrogen. DSC and element analysis detection are carried out on the fiber after the thermal stabilization treatment, and the detection result is compared with the conventional all-air medium thermal stabilization fiber, such as the ratio shown in Table 1:

TABLE 1

Example 2

In the implementation process, the temperature settings of the 1# -6# oxidation furnace are respectively as follows: the heating medium of the No. 1-4 oxidation furnace is air at 210 ℃, 230 ℃, 237 ℃, 243 ℃, 255 ℃ and 260 ℃, and the heating medium of the No. 5 and No. 6 oxidation furnaces is nitrogen. DSC and element analysis detection are carried out on the fiber after the thermal stabilization treatment, and the detection result is compared with the conventional all-air medium thermal stabilization fiber, such as the ratio shown in Table 2:

TABLE 2

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the concept of the present invention, and these improvements and decorations should also be considered as within the protection scope of the present invention.

Claims

1. A thermal stabilization device for carbon fiber production is characterized in that a No. 1 oxidation furnace, a No. 2 oxidation furnace, a No. 3 oxidation furnace, a No. 4 oxidation furnace, a No. 5 oxidation furnace, a No. 6 oxidation furnace, a low-temperature carbonization furnace and a high-temperature carbonization furnace are sequentially arranged; are connected in sequence through pipelines.

2. The thermal stabilization apparatus for carbon fiber production according to claim 1, wherein the # 1 oxidation furnace, the # 2 oxidation furnace, the # 3 oxidation furnace, and the # 4 oxidation furnace use air as a medium.

3. The thermal stabilization apparatus for carbon fiber production according to claim 1, wherein the 5# and 6# oxidation furnaces use nitrogen gas as a medium or the 1# oxidation furnace-5 # oxidation furnace uses air as a medium.

4. The thermal stabilization apparatus for carbon fiber production according to claim 1, wherein the 6# oxidation furnace uses nitrogen gas as a medium.