CN110257959B - Carbon fiber microwave graphitization equipment capable of continuously processing - Google Patents
Carbon fiber microwave graphitization equipment capable of continuously processing Download PDFInfo
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- CN110257959B CN110257959B CN201910571990.7A CN201910571990A CN110257959B CN 110257959 B CN110257959 B CN 110257959B CN 201910571990 A CN201910571990 A CN 201910571990A CN 110257959 B CN110257959 B CN 110257959B
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- 229920000049 Carbon (fiber) Polymers 0.000 title claims abstract description 122
- 239000004917 carbon fiber Substances 0.000 title claims abstract description 122
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 94
- 238000005087 graphitization Methods 0.000 title claims abstract description 27
- 238000012545 processing Methods 0.000 title abstract description 10
- 238000010438 heat treatment Methods 0.000 claims abstract description 145
- 238000007789 sealing Methods 0.000 claims abstract description 51
- 230000001681 protective effect Effects 0.000 claims abstract description 26
- 229910052751 metal Inorganic materials 0.000 claims abstract description 10
- 239000002184 metal Substances 0.000 claims abstract description 10
- 238000001816 cooling Methods 0.000 claims abstract description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 12
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- 238000004804 winding Methods 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 4
- 101100063437 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) DIN7 gene Proteins 0.000 claims description 3
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- 239000007789 gas Substances 0.000 description 48
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 14
- 239000011261 inert gas Substances 0.000 description 14
- 239000000463 material Substances 0.000 description 10
- 238000010586 diagram Methods 0.000 description 9
- 230000006698 induction Effects 0.000 description 8
- 239000011521 glass Substances 0.000 description 7
- 229910052757 nitrogen Inorganic materials 0.000 description 7
- 239000011357 graphitized carbon fiber Substances 0.000 description 6
- 230000005855 radiation Effects 0.000 description 6
- 239000011241 protective layer Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- -1 copper Chemical class 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 238000001179 sorption measurement Methods 0.000 description 3
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 239000000112 cooling gas Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
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- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
- D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
- D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
Abstract
The invention discloses carbon fiber microwave graphitization equipment capable of continuously processing, wherein an inlet gas dynamic sealing device and an outlet gas dynamic sealing device are respectively arranged on two sides of a microwave heating cavity, two sides of the microwave heating cavity are respectively connected with the inlet gas dynamic sealing device and the outlet gas dynamic sealing device in a sealing way through metal pipes, a protective gas inlet pipe is further connected between the microwave heating cavity and the inlet gas dynamic sealing device, and a protective gas air cooling pipe is further connected between the microwave heating cavity and the outlet gas dynamic sealing device. The invention comprises a microwave measurement and control system, can monitor the change of the incident/reflected power in real time, adjust the frequency in real time, and ensure that the solid-state microwave source and the cavity have better matching degree; the invention also provides a plurality of cylindrical cavities capable of simultaneously processing N paths of carbon fibers, so that the production efficiency is greatly improved; simple structure, small volume, low cost and convenient mass production.
Description
Technical Field
The invention relates to the technical field of carbon fiber graphitization heating, in particular to carbon fiber microwave graphitization equipment capable of continuously processing.
Background
The high modulus graphitized carbon fibers, also referred to as graphite fibers for short, are generally considered to have a modulus of less than 344GPa and a modulus of greater than 344GPa. The graphite fiber has excellent properties of high modulus, high strength, low specific gravity and the like, and is a key strategic material for national defense and national economy construction. At present, domestic carbon fiber materials are mainly applied to sports and leisure articles, but the proportion of industrial grade carbon fibers is gradually improved in recent years, and the demand of industrial grade and military grade high-modulus graphitized carbon fibers is huge. The graphitized carbon fiber is produced at a higher heating temperature, and the graphitization temperature is theoretically 2500 to 3000 ℃.
Microwave heating devices have a long history of heating of materials by absorption of microwave energy by themselves, the specific principle being the overall heating of the material in an electromagnetic field due to its dielectric losses. The carbon fiber microwave graphitization is based on the heating principle, the carbon content of the carbonized carbon fiber reaches more than 90%, and the carbon fiber has excellent microwave absorption characteristics; the microwave heating has selectivity, and only the carbon fiber tows can be heated without heating the furnace wall, so that the problem of heating efficiency is solved, the generation of skin-core phenomenon is avoided, and the service life of the heating device can be greatly prolonged.
Most of domestic enterprises and research institutions currently adopt a traditional heat radiation heating mode, and a hearth is heated first in an intermediate frequency heating mode, so that the temperature in the whole furnace reaches a proper heating interval, and carbon fiber tows continuously pass through the whole heating area to finish graphitization processing of carbon fibers. This approach has mainly the following drawbacks: (1) The traditional heating mode has slow heating rate and lower thermal efficiency; (2) The inner wall material of the traditional heating hearth can not bear the high temperature of more than 2000 ℃, and the hearth is extremely easy to crack and incinerate under the baking effect of long-time high temperature, so that the service life of the hearth is greatly shortened.
The carbon fiber microwave heating is different from the traditional radiation heating in the heat transfer mode: (1) The traditional heat radiation method is to radiate heat to the surface of an object through far infrared rays, and then conduct the heat from the surface to the inside of the object through a heat conduction mode, so that a certain temperature difference can be generated between the inside and the outside of the object, and skin-core phenomenon can be possibly caused; (2) The microwave heating is to heat the inside and the outside of the object simultaneously due to dielectric loss, does not need heat conduction, is quicker and more uniform in heating, and is very suitable for heating carbon fiber tows.
In addition to the conventional radiation heating method described above, there is a high-frequency induction heating method. The Chinese patent (patent application number: 02135138) discloses a method for producing high-strength high-modulus carbon fiber and special equipment thereof, which adopts a high-frequency induction heating mode, and the method mainly has the following defects: (1) The conductivity of the carbon fiber is much smaller than that of metals such as copper, so that the high-frequency induction heating efficiency is lower; (2) Because the high-frequency heater is easy to be subjected to external voltage fluctuation, the output power is unstable, the heating temperature fluctuation of the carbon fiber is obvious, and the product quality is influenced.
Compared with the traditional high-frequency induction heating, the carbon fiber microwave heating has the following differences in heating mode: (1) The high-frequency induction heating is a process of generating an alternating magnetic field in a heating zone, and generating eddy current by carbon fibers under the induction of the alternating magnetic field, thereby generating a heating effect. However, compared with metals such as copper, the conductivity of the carbon fiber is much smaller, so that the high-frequency induction heating efficiency is lower, and meanwhile, the problem of unstable output power exists; (2) Microwave heating is a process of absorbing microwave energy and converting it into heat mainly by dielectric polarization relaxation loss of carbon fibers. Meanwhile, carbon fiber is a high-loss medium, so that the microwave heating efficiency is extremely high. The output power of the solid microwave source for generating microwaves is more stable, and the quality of carbon fiber products is guaranteed.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides carbon fiber microwave graphitization equipment capable of continuously processing.
The invention is realized by the following technical scheme:
the carbon fiber microwave graphitization equipment capable of continuously processing comprises a microwave heating cavity, a microwave source, a carbon fiber wire unwinding roller and a carbon fiber wire winding roller, microwaves generated by the microwave source are fed into the microwave heating cavity from the side face of the microwave heating cavity, an inlet gas dynamic sealing device and an outlet gas dynamic sealing device are respectively arranged at two sides of the microwave heating cavity, two sides of the microwave heating cavity are respectively in sealing connection with the inlet gas dynamic sealing device and the outlet gas dynamic sealing device through metal pipes, a protective gas inlet pipe is further connected between the microwave heating cavity and the inlet gas dynamic sealing device, a protective gas air cooling pipe is further connected between the microwave heating cavity and the outlet gas dynamic sealing device, protective gas is introduced into the microwave heating cavity through the protective gas inlet pipe, air cooling gas is introduced into the heated carbon fiber bundles through the protective gas air cooling pipe, a temperature measuring device is further arranged at the outer side of the microwave heating cavity, carbon fiber wires on the carbon fiber wire unwinding roller sequentially penetrate through the inlet gas dynamic sealing device and the microwave heating cavity, and the carbon fiber wires are heated through the microwave wire winding roller and the carbon fiber wires are sequentially and then wound through the microwave heating device.
The microwave heating device also comprises a microwave control unit, wherein the microwave control unit monitors the incidence/reflection power of the microwave heating cavity in real time and adjusts the power output by the microwave source according to the reflection power.
The microwave source adopts a solid-state microwave circuit, has accurate microwave power adjustment and frequency adjustment functions, outputs single-path or multi-path microwave power at the same time, has frequency points of 315MHz, 433MHz, 915MHz and 2450MHz, has bandwidth of 100MHz, and adopts a coaxial line direct coupling mode to feed microwaves from the side surface of the microwave heating cavity through a DIN7/16 standard connector.
The microwave heating cavity is a cylindrical cavity, and is provided with a single-path structure and an N-path structure: the single-path is to feed microwaves from the side surface of the cylindrical cavity, and process carbon fibers in the center of the cavity; the N paths are divided into the following: (1) The center of the cavity is fed with microwaves, and N paths of carbon fibers are symmetrically distributed around the cavity; (2) N identical coaxial lines for feeding microwaves are symmetrically distributed inside, and N paths of carbon fibers are symmetrically distributed outside; (3) N identical coaxial lines for feeding microwaves are symmetrically distributed outside, and N paths of carbon fibers are symmetrically distributed inside, wherein N is more than or equal to 4.
The single-path cylindrical cavity comprises a cylinder, cover plates are respectively fixed on two sides of the cylinder, round holes are respectively formed in the two cover plates, shielding sleeves are respectively connected to the two round holes, the two shielding sleeves are respectively connected with an inlet gas dynamic sealing device and an outlet gas dynamic sealing device, and two rotary cover plates for tuning are respectively arranged on the two cover plates.
And a quartz glass tube is arranged in the microwave heating cavity, and the carbon fiber tows continuously pass through the microwave heating cavity in the quartz glass tube for microwave heating. The quartz glass tube passes through the cavity, the carbon fiber tows continuously pass through the cavity in the quartz glass tube for microwave heating, and measures such as no glass tube, tube replacement or adsorption material addition can be adopted in consideration of the problem of high-temperature volatilization of carbon fibers; a dynamic sealing device and an air sealing device are arranged at the inlet and the outlet of the carbon fiber tows; the high-temperature graphitized carbon fiber tows at the outlet are forced to wind by adopting high-purity nitrogen, other inert gases or mixed gases of different inert gases.
The microwave heating temperature can reach more than 2500 ℃, and the microwave heating is continuously and uniformly carried out; the temperature measuring device adopts non-contact laser aiming infrared thermometer to measure temperature.
To achieve the temperature required for graphitization, a cascade combination of multiple cavities in series may be employed. And connecting a plurality of identical microwave heating cavities in series, wherein each microwave heating cavity is connected with a microwave source, and the carbon fiber tows are heated by sequentially passing through the plurality of microwave heating cavities connected in series.
The protective gas is usually composed of high-purity nitrogen, other inert gases or mixed gases of different inert gases, and a small amount of boron element can be added into the protective gas in order to accelerate the graphitization speed.
The invention has the advantages that: (1) For high strength high modulus carbon fibers, the graphitization heating temperature should generally be above 2500 ℃. The microwave graphitization equipment is adopted, so that the temperature can be improved by about hundreds of degrees compared with the conventional heat radiation heating temperature; (2) The microwave graphitizing device is a device for heating the carbon fiber tows by microwaves, and is completely different from a heat radiation heating mode, and the heating mode of heating the carbon fiber tows by microwaves is internal and external integral simultaneous heating, so that the heating mode can not generate a sheath-core phenomenon. The heating of the carbon fiber tows is completed in a microwave cavity, and the temperature of the inner wall of the cavity is not high, so that the inner wall of the heater cannot crack or incinerate, and the service life of the heater can be greatly prolonged; (3) Compared with metals such as copper, the conductivity of the carbon fiber is smaller, so that the high-frequency induction heating efficiency is lower, and meanwhile, the problem of unstable output power exists. Microwave heating is a process of absorbing microwave energy and converting it into heat mainly by dielectric polarization relaxation loss of carbon fibers. Meanwhile, carbon fiber is a high-loss medium, so that the microwave heating efficiency is extremely high. The output power of the solid microwave source for generating microwaves is more stable, and the quality of carbon fiber products is guaranteed; (4) The microwave graphitization equipment only heats the carbon fiber tows and does not heat other parts, so that the heating mode has extremely high heating efficiency; (5) The invention comprises a microwave measurement and control system, can monitor the change of the incident/reflected power in real time, adjust the frequency in real time, and ensure that the solid-state microwave source and the cavity have better matching degree; (6) The invention also provides a plurality of cylindrical cavities capable of simultaneously processing N paths of carbon fibers (N is more than or equal to 4), so that the production efficiency is greatly improved; (7) As a revolutionary carbon fiber microwave graphitizing device, the device has the advantages of simple structure, small volume, low cost and convenient mass production.
Drawings
Fig. 1 is a schematic diagram of a two-dimensional structure of a carbon fiber microwave graphitizing device.
Fig. 2 is a schematic diagram of a three-dimensional structure of a carbon fiber microwave graphitizing device.
Fig. 3 is a schematic diagram of a single-pass microwave heating cavity.
Fig. 4 is a schematic diagram of a microwave heating cavity structure in which microwaves are fed into the center of the cavity and four paths of carbon fibers are symmetrically distributed around the cavity.
Fig. 5 is a schematic diagram of a microwave heating cavity with four identical coaxial lines for feeding microwaves symmetrically distributed inside and four paths of carbon fibers symmetrically distributed outside.
Fig. 6 is a schematic diagram of a microwave heating cavity with four identical coaxial lines for feeding microwaves symmetrically distributed outside and four paths of carbon fibers symmetrically distributed inside.
Fig. 7 is a schematic diagram of a cascade combination of multiple microwave heating chambers.
Fig. 8 is a schematic diagram of a microwave measurement and control system.
Fig. 8 is a schematic diagram of a microwave measurement and control system.
FIG. 9 is a schematic view of a non-contact labyrinth seal.
Detailed Description
As shown in fig. 1, the carbon fiber microwave graphitization device capable of continuously processing comprises a microwave heating cavity 1, a microwave source 2, a carbon fiber wire unwinding roller 3 and a carbon fiber wire winding roller 4, microwaves generated by the microwave source 2 are fed into the microwave heating cavity 1 from the side surface of the microwave heating cavity 1, an inlet gas dynamic sealing device 5 and an outlet gas dynamic sealing device 6 are respectively arranged at two sides of the microwave heating cavity 1, two sides of the microwave heating cavity 1 are respectively in sealing connection with the inlet gas dynamic sealing device 5 and the outlet gas dynamic sealing device 6 through metal pipes, a protective gas inlet pipe 7 is further connected between the microwave heating cavity 1 and the inlet gas dynamic sealing device 5, a protective gas air cooling pipe 8 is further connected between the microwave heating cavity 1 and the outlet gas dynamic sealing device 6, protective gas is introduced into the microwave heating cavity 1 through the protective gas inlet pipe 7, the air cooling gas is forced to the heated carbon fiber wire bundles, a temperature measuring device 9 is further arranged at the outer side of the microwave heating cavity 1, the carbon fiber wire unwinding roller 3 passes through the inlet gas dynamic sealing device 5 and the carbon fiber wire winding roller 1, and the carbon fiber wire is sequentially heated through the microwave heating cavity 1, and the carbon fiber wire is sequentially wound up through the inlet gas dynamic sealing device 4, and the carbon fiber wire is sequentially heated through the microwave heating cavity 1.
The microwave heating device also comprises a microwave control unit 10, wherein the microwave control unit 10 monitors the incidence/reflection power of the microwave heating cavity in real time, and adjusts the power output by the microwave source according to the reflection power.
The microwave source 2 adopts a solid-state microwave circuit, has precise microwave power regulation and frequency regulation functions, outputs single-path or multi-path microwave power at the same time, has frequency points of 315MHz, 433MHz, 915MHz and 2450MHz, has bandwidth of 100MHz, adopts a coaxial line direct coupling mode, feeds microwaves from the side surface of a microwave heating cavity through a DIN7/16 standard connector, and heats carbon fiber tows in an electromagnetic focusing mode. .
The microwave heating cavity 1 is a cylindrical cavity, and has a one-way structure and an N-way structure: the single-path is to feed microwaves from the side surface of the cylindrical cavity, and process carbon fibers in the center of the cavity; the N paths are divided into the following: (1) The center of the cavity is fed with microwaves, and N paths of carbon fibers are symmetrically distributed around the cavity; (2) N identical coaxial lines for feeding microwaves are symmetrically distributed inside, and N paths of carbon fibers are symmetrically distributed outside; (3) N identical coaxial lines for feeding microwaves are symmetrically distributed outside, and N paths of carbon fibers are symmetrically distributed inside, wherein N is more than or equal to 4.
The single-path cylindrical cavity comprises a cylinder 11, cover plates 12 are respectively fixed on two sides of the cylinder 11, round holes are formed in the two cover plates 12, shielding sleeves 13 are respectively connected to the two round holes, the two shielding sleeves 13 are respectively connected with an inlet gas dynamic sealing device 5 and an outlet gas dynamic sealing device 6, and two rotary cover plates 14 for tuning are respectively arranged on the two cover plates. The cylindrical cavity is made of metal aluminum;
a quartz glass tube is arranged in the microwave heating cavity 1, and carbon fiber tows continuously pass through the microwave heating cavity in the quartz glass tube for microwave heating. The quartz glass tube passes through the cavity, the carbon fiber tows continuously pass through the cavity in the quartz glass tube for microwave heating, and measures such as no glass tube, tube replacement or adsorption material addition can be adopted in consideration of the problem of high-temperature volatilization of carbon fibers; a dynamic sealing device and an air sealing device are arranged at the inlet and the outlet of the carbon fiber tows; the high-temperature graphitized carbon fiber tows at the outlet are forced to wind by adopting high-purity nitrogen, other inert gases or mixed gases of different inert gases.
The microwave heating temperature can reach more than 2500 ℃, and the microwave heating is continuously and uniformly carried out; the temperature measuring device 9 adopts non-contact laser aiming infrared thermometer to measure temperature.
To achieve the temperature required for graphitization, a cascade combination of multiple cavities in series may be employed. The method comprises the steps of connecting a plurality of identical microwave heating cavities 1 in series, wherein each microwave heating cavity 1 is connected with a microwave source 2, and carbon fiber tows are heated through the plurality of microwave heating cavities connected in series in sequence.
The glass tube passes through the cavity through the two through holes, the carbon fiber tows are continuously heated in the glass tube through the cavity absorbing microwaves, and measures such as no glass tube, tube replacement or adsorption material addition can be adopted in consideration of the problem of high-temperature volatilization of carbon fibers.
The solid microwave source generates microwaves, the microwaves are fed into the cylindrical cavity through the coaxial line to generate resonance, and the microwaves heat the carbon fiber tows in an electromagnetic focusing mode; the cylindrical cavity is essentially a microwave heater, and the microwave heater adopted by the invention is not limited to the cylindrical heater, but also comprises a rectangular heater, an elliptic and spherical heater, a disk load waveguide heater, a medium loading heater, a travelling wave cavity heater and the like.
The cylindrical cavity is designed to maximize the electric field intensity near the carbon fiber tows so as to improve the heating efficiency of the carbon fibers; the design of the cylindrical cavity also ensures that the resonant frequency of the cylindrical cavity is matched with that of the solid-state microwave source.
In order to avoid substituting air into the cavity when the carbon fiber tows move, a dynamic sealing device and an air sealing device are required to be arranged at the inlet and the outlet of the carbon fiber tows; in order to prevent the high-temperature oxidation of the outlet, the high-temperature graphitized carbon fiber tows at the outlet are forced to be cooled by adopting high-purity nitrogen, other inert gases or mixed gases of different inert gases.
The temperature measuring device 9 directly measures smaller objects by utilizing the infrared non-contact measuring principle in an optical focusing mode, and the accuracy can reach 0.5%.
The microwave control unit 10 can monitor the incident/reflected power of the cylindrical resonant cavity in real time, and adjust the frequency of the microwave output of the microwave source according to the reflected power, so that the resonant frequency of the cylindrical resonant cavity is matched with the frequency of the microwave output by the microwave source.
The protective gas is usually composed of high-purity nitrogen, other inert gases or mixed gases of different inert gases, and a small amount of boron element can be added into the protective gas in order to accelerate the graphitization speed.
The carbon fiber microwave graphitization equipment adopts microwave power to heat the carbon fiber tows, and the temperature is increased to the reaction temperature required by graphitization by inputting protective gas, so that the graphitization process can be completed rapidly.
The microwave graphitization temperature should reach above 2500 ℃, and the stability of the heating process needs to be ensured. Before heating, the protective layer on the surface of the carbon fiber tows needs to be washed by hot water; after the heating is completed, a protective layer needs to be re-plated on the surface of the carbon fiber. In the heating area of the cavity, the carbon fiber tows cannot be in direct contact with the inner wall of the heating cavity, otherwise the inner wall of the cavity is burnt out.
As shown in fig. 9, the inlet gas dynamic sealing device 5 and the outlet gas dynamic sealing device are both non-contact labyrinth sealing devices, a protective gas expansion chamber 22 is formed between the baffles 23, protective gas enters the expansion chamber 22 through the inlet 24, the incident direction of the protective gas is perpendicular to the moving direction of the carbon fiber tows, the carbon fiber tows enter the sealing device from the tow inlet 21, and leave the sealing device from the tow outlet 25. The purpose is to prevent air from entering from the carbon fiber tow inlet and outlet, so that the carbon fiber tow is oxidized by air during graphitization.
In order to discharge the air in the glass tube reactor, a protective gas is required to be introduced into the glass tube, wherein the protective gas is usually composed of high-purity nitrogen, other inert gases or mixed gases of different inert gases; the reactor material for carbon fiber microwave graphitization is high-purity quartz glass, a sealing structure is adopted between the reactor material and a metal pipe to prevent air from entering, and carbon fibers are fixed at the central position of a cavity through a throat pipe arranged in the quartz glass pipe reactor; punching holes at different positions of the carbon fiber outlet, installing a temperature measuring tube, and measuring the outlet temperature of the carbon fiber by adopting a non-contact laser aiming infrared thermometer; the microwave control unit consists of a solid-state microwave source, a temperature sensor, an industrial personal computer, a digital analog controller and the like, and the industrial personal computer drives the digital analog controller after obtaining a temperature signal, so that the power of the solid-state microwave amplifier for outputting microwaves is controlled to meet the temperature required by graphitization of the carbon fiber. In addition, the industrial personal computer can also control the frequency of microwaves, the air flow of protective gas and the pulling force and speed of winding and unwinding wires; the air cooling device cools the carbon fiber by adopting high-purity nitrogen, other inert gases or mixed gases of different inert gases, reduces the temperature of the carbon fiber in a short time, and prevents the phenomenon of skin-core caused by different expansion coefficients of the carbon fiber.
The carbon fiber microwave heating cavity in fig. 1 can be represented by a cascade combination of a plurality of microwave heating cavities in series as shown in fig. 7, and the cascade combination of the plurality of cavities in series is more beneficial to heating the carbon fiber tow to the temperature required for graphitization.
In the heating area of the cavity, the carbon fiber tows cannot be in direct contact with the inner wall of the heating cavity, otherwise the inner wall of the cavity is burnt out. Before heating, the protective layer on the surface of the carbon fiber tows needs to be washed by hot water; after the heating is completed, a protective layer needs to be re-plated on the surface of the carbon fiber.
The microwave measurement and control system refers to a novel automobile ignition control system (patent application number: 201710333159) of China patent. Fig. 8 shows a microwave measurement and control system in a carbon fiber microwave heating process, in which a phase-locked source 15, a driving stage 16, an amplifying stage 17, a coupler 18 and a microwave heating cavity 1 are sequentially connected, the coupler 18 transmits coupled incident/reflected power to a detector 19, the detector 19 converts a microwave signal into an analog signal and transmits the analog signal to a processor 20, and the processor 20 combines a corresponding algorithm according to the detected signal to realize the adjustment of the frequency and amplitude of the microwave output by the phase-locked source 15.
Claims (1)
1. A carbon fiber microwave graphitization device capable of being continuously processed is characterized in that: the microwave heating device comprises a microwave heating cavity, a microwave source, a carbon fiber wire unwinding roller and a carbon fiber wire winding roller, microwaves generated by the microwave source are fed into the microwave heating cavity from the side face of the microwave heating cavity, an inlet gas dynamic sealing device and an outlet gas dynamic sealing device are respectively arranged at two sides of the microwave heating cavity, two sides of the microwave heating cavity are respectively connected with the inlet gas dynamic sealing device and the outlet gas dynamic sealing device in a sealing manner through metal pipes, a protective gas inlet pipe is further connected between the microwave heating cavity and the inlet gas dynamic sealing device, a protective gas air cooling pipe is further connected between the microwave heating cavity and the outlet gas dynamic sealing device, protective gas is introduced into the microwave heating cavity through the protective gas air cooling pipe to force the heated carbon fiber wire bundles to be cooled, a temperature measuring device is further arranged at the outer side of the microwave heating cavity, carbon fiber wires on the carbon fiber wire unwinding roller sequentially pass through the inlet gas dynamic sealing device and the microwave heating cavity, and the carbon fiber wires are heated through the microwaves when passing through the microwave heating cavity, and the heated carbon fiber wires pass through the outlet gas dynamic sealing device and are wound through the microwave heating cavity;
the microwave heating device also comprises a microwave control unit, wherein the microwave control unit monitors the incidence/reflection power of the microwave heating cavity in real time and adjusts the power of microwave output of the microwave source according to the magnitude of the reflection power;
the microwave source adopts a solid microwave circuit, simultaneously outputs single-path or multi-path microwave power, has frequency points of 315MHz, 433MHz, 915MHz and 2450MHz, has bandwidth of 100MHz, and adopts a coaxial line direct coupling mode to feed microwaves from the side surface of a microwave heating cavity through a DIN7/16 standard connector;
the microwave heating cavity is a cylindrical cavity, and is provided with a single-path structure and an N-path structure: the single-path is to feed microwaves from the side surface of the cylindrical cavity, and process carbon fibers in the center of the cavity; the N paths are divided into the following: (1) The center of the cavity is fed with microwaves, and N paths of carbon fibers are symmetrically distributed around the cavity; (2) N identical coaxial lines for feeding microwaves are symmetrically distributed inside, and N paths of carbon fibers are symmetrically distributed outside; (3) N identical coaxial lines for feeding microwaves are symmetrically distributed outside, and N paths of carbon fibers are symmetrically distributed inside, wherein N is more than or equal to 4;
the single-way comprises a cylinder, cover plates are respectively fixed on two sides of the cylinder, round holes are formed in the centers of the two cover plates, shielding sleeves are respectively connected to the two round holes, the two shielding sleeves are respectively connected with an inlet gas dynamic sealing device and an outlet gas dynamic sealing device, and two rotary cover plates for tuning are respectively arranged on the two cover plates;
a quartz glass tube is arranged in the microwave heating cavity, and the carbon fiber tows continuously pass through the microwave heating cavity to be subjected to microwave heating in the quartz glass tube;
the temperature measuring device adopts non-contact laser aiming infrared thermometer to measure temperature;
and a plurality of identical microwave heating cavities are connected in series through metal pipes, each microwave heating cavity is connected with a microwave source, and the carbon fiber tows are heated by the plurality of microwave heating cavities connected in series in sequence.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910571990.7A CN110257959B (en) | 2019-06-28 | 2019-06-28 | Carbon fiber microwave graphitization equipment capable of continuously processing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910571990.7A CN110257959B (en) | 2019-06-28 | 2019-06-28 | Carbon fiber microwave graphitization equipment capable of continuously processing |
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| CN1696365A (en) * | 2004-05-11 | 2005-11-16 | 陈新谋 | Microwave thermal reaction device for graphitizing carbon fiber and processing technique |
| WO2006101084A1 (en) * | 2005-03-23 | 2006-09-28 | Bridgestone Corporation | Carbon fiber and processes for (continuous) production thereof, and catalyst structures, electrodes for solid polymer fuel cells, and solid polymer fuel cells, made by using the carbon fiber |
| CN202830266U (en) * | 2012-07-12 | 2013-03-27 | 永虹科技股份有限公司 | Manufacture device of high-module graphite fibers |
| CN103541042A (en) * | 2012-07-12 | 2014-01-29 | 永虹科技股份有限公司 | High-modulus graphite fiber and preparation method thereof |
| CN104294407A (en) * | 2014-10-15 | 2015-01-21 | 北京化工大学 | Shaft core focused carbon fiber graphitization furnace through laser tunnel reflection method |
| CN109594151A (en) * | 2018-12-25 | 2019-04-09 | 中国科学院合肥物质科学研究院 | A kind of equipment optimizing carbon fiber and graphite |
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| CN1696365A (en) * | 2004-05-11 | 2005-11-16 | 陈新谋 | Microwave thermal reaction device for graphitizing carbon fiber and processing technique |
| WO2006101084A1 (en) * | 2005-03-23 | 2006-09-28 | Bridgestone Corporation | Carbon fiber and processes for (continuous) production thereof, and catalyst structures, electrodes for solid polymer fuel cells, and solid polymer fuel cells, made by using the carbon fiber |
| CN202830266U (en) * | 2012-07-12 | 2013-03-27 | 永虹科技股份有限公司 | Manufacture device of high-module graphite fibers |
| CN103541042A (en) * | 2012-07-12 | 2014-01-29 | 永虹科技股份有限公司 | High-modulus graphite fiber and preparation method thereof |
| CN104294407A (en) * | 2014-10-15 | 2015-01-21 | 北京化工大学 | Shaft core focused carbon fiber graphitization furnace through laser tunnel reflection method |
| CN109594151A (en) * | 2018-12-25 | 2019-04-09 | 中国科学院合肥物质科学研究院 | A kind of equipment optimizing carbon fiber and graphite |
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