A fiber oxidation level adjustment system and method
By monitoring the oxygen content of the oxidized fiber in real time during the carbon fiber production process and adjusting the mixed gas in the oxidation furnace, the problem of lag in oxidation treatment was solved, production costs were reduced, and fiber performance was improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHAANXI TIANCE NEW MATERIAL TECH
- Filing Date
- 2023-12-22
- Publication Date
- 2026-05-12
Smart Images
Figure CN117702311B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of carbon fiber production, and particularly relates to a fiber oxidation degree adjusting system and method. BACKGROUND
[0002] Carbon fiber is a fibrous carbon material, which has a lower density than aluminum but a higher strength than steel, and has properties such as corrosion resistance and high modulus. The above properties are closely related to the processing technology of carbon fiber. Among them, the oxidation treatment in the processing and production of carbon fiber has a great influence on the properties of carbon fiber. The oxidation treatment of carbon fiber is usually carried out in a gas atmosphere with oxidizing property. The main process parameters of oxidation treatment are temperature, time, and oxidant type. During the oxidation reaction of carbon fiber, cross-linking polymerization of organic molecules occurs, alkyl carbon forms active points, and carbonyl, carboxyl and phenoxy groups are formed through the intervention of oxygen, thereby increasing the softening point of carbon fiber and preventing the carbon fiber from fusing and thermal decomposition during subsequent higher temperature carbonization and graphitization treatment. The oxygen content of the carbon fiber after oxidation increases. For mesophase pitch fibers with a diameter of less than 20 μm, the oxygen content of the carbon fiber after oxidation is 6% to 10%. Too low oxygen content will result in insufficient oxidation, and too high oxygen content will result in excessive oxidation, both of which will reduce the strength of the final carbon fiber. In addition, the carbon fiber needs to be uniformly oxidized during the oxidation process, that is, the oxygen content difference of every 1 μm volume depth from the surface to the core of the carbon fiber needs to be controlled within 1%, so as to avoid the formation of a skin-core structure with low oxygen content in the core and high oxygen content on the surface of the carbon fiber.
[0003] At present, carbon fiber is produced and prepared by sequentially going through the steps of melt spinning, oxidation, carbonization, and graphitization. The prepared carbon fiber is subjected to oxygen content detection. The intuitive detection of the oxygen content of the carbon fiber is carried out by detecting the density of the carbon fiber, that is, the weight change of the carbon fiber of a specific length is used to judge the change in the density of the carbon fiber, which reflects the difference in the oxidation degree of the carbon fiber. Then, the oxidation parameters of the carbon fiber are adjusted according to the reflected difference in the oxidation degree of the carbon fiber. In the production of carbon fiber, oxidation is an intermediate step in the processing procedure. The oxidation degree of the carbon fiber is fed back by detecting the oxygen content of the prepared carbon fiber or the performance of the final carbon fiber, which has a serious lag. Therefore, the oxidation parameters in the production steps of the carbon fiber cannot be adjusted in real time, and the actual effect of the oxidation treatment cannot be reflected in real time during the production process. As a result, the oxygen content error in the unit volume of the produced carbon fiber is large, which causes a high rate of defective products of the carbon fiber and a high production cost. SUMMARY
[0004] In order to solve the problem that the oxidation parameters of the carbon fiber cannot be adjusted in real time after oxidation in the production of carbon fiber in the prior art, and the oxidation feedback has a lag, resulting in a high production cost, the present application provides a fiber oxidation degree adjusting system. Furthermore, based on the above-mentioned system, the present application also provides a method for adjusting the oxidation degree of the fiber.
[0005] To achieve the above objectives, the present invention provides the following technical solution:
[0006] A fiber oxidation degree adjustment system includes an oxidation furnace, a detection module, and a gas regulation module.
[0007] The oxidation furnace is used to oxidize the fibers;
[0008] The detection module is located at the fiber outlet of the oxidation furnace and is used to detect the oxygen content of the fiber after oxidation in real time, and generate an adjustment signal based on the oxygen content.
[0009] The gas regulation module is located at the air inlet of the oxidation furnace and is used to input mixed gas into the oxidation furnace. The gas regulation module is communicatively connected to the detection module and is used to adjust the flow rate of the mixed gas input into the oxidation furnace and the oxygen content in the mixed gas according to the regulation signal.
[0010] Preferably, the detection module includes a fiber winder and a counterweight.
[0011] The fiber winder is located at the filament outlet of the oxidation furnace and is used to wind the fiber N turns.
[0012] The fiber winder is connected to one end of a lever, and the other end of the lever is connected to the counterweight. A sensor is installed on the lever. The sensor is used to obtain the swing signal of the lever when the weight of the fiber wound on the fiber winder changes based on the change in the weight of the fiber wound on a set length, and generate the adjustment signal.
[0013] The sensor is communicatively connected to the gas regulation module and transmits the regulation signal to the gas regulation module;
[0014] The gas regulation module includes a gas mixer with two air inlets, one of which is connected to an oxidizing gas source and the other is connected to a rare gas source.
[0015] The outlet of the gas mixer is connected to the inlet of the oxygen analyzer, and the outlet of the oxygen analyzer is connected to the inlet of the oxidation furnace.
[0016] Preferably, a third flow controller is provided on the connecting pipe between the outlet of the oxygen analyzer and the inlet of the oxidation furnace. The third flow controller is communicatively connected to the sensor and is used to control the flow rate of the mixed gas entering the oxidation furnace according to the adjustment signal.
[0017] Preferably, a first flow controller is provided between the oxidizing gas source and one of the air inlets on the gas mixer; a second flow controller is provided between the rare gas source and the other air inlet of the gas mixer. The first flow controller and the second flow controller are respectively communicatively connected to the sensor and are used to adjust the flow rate of the gas entering the gas mixer according to the adjustment signal.
[0018] Preferably, the oxidizing gas is oxygen; the rare gas is one of nitrogen, argon or helium.
[0019] A method for adjusting the degree of fiber oxidation, using the above-mentioned system, includes:
[0020] Set the fiber oxidation parameters and oxidize the initial fiber segment;
[0021] After the oxidized initial fiber segment is wound around the fiber winder to a set length, the end of the fiber is pulled to the next fiber processing step. The counterweight is adjusted to balance the lever, and fiber preparation begins, driving the fiber winder to rotate.
[0022] In the fiber preparation process, the swing angle and swing direction of the lever are obtained by the sensor based on the change in weight of the fiber wound to a set length on the fiber winder, and an adjustment signal is generated based on the swing angle and swing direction of the lever.
[0023] The oxygen content of the mixed gas in the oxidation furnace is adjusted in real time based on the adjustment signal, thereby adjusting the degree of fiber oxidation.
[0024] Preferably, the real-time adjustment of the oxygen content of the mixed gas in the oxidation furnace based on the adjustment signal includes a third flow controller acquiring the adjustment signal and adjusting the flow rate of the mixed gas input into the oxidation furnace by the gas mixer.
[0025] Preferably, the real-time adjustment of the oxygen content of the mixed gas in the oxidation furnace based on the adjustment signal includes the second flow controller and the first flow controller adjusting the proportion of the input gas mixer based on the adjustment signal, thereby changing the oxygen content of the mixed gas in the gas mixer.
[0026] Preferably, when the mixed gas in the gas mixer is fed into the oxidation furnace, an oxygen analyzer is used to detect the oxygen content.
[0027] Preferably, the fiber is wound around the fiber winder 5 to 10 times.
[0028] Compared with the prior art, the present invention has the following beneficial technical effects:
[0029] 1. In this invention, a detection module is installed at the fiber outlet of the oxidation furnace. The detection module detects the oxygen content of the oxidized fiber in real time and generates an adjustment signal. The gas adjustment module adjusts the oxygen content of the mixed gas input into the oxidation furnace according to the adjustment signal, thereby realizing real-time adjustment of the degree of fiber oxidation. This system can adjust the oxygen content of the mixed gas input into the oxidation furnace after the fiber is oxidized during the fiber production process. The adjustment is convenient and rapid, avoiding the occurrence of lag in the adjustment of the degree of fiber oxidation, thereby reducing the production cost of fiber, reducing the difference in the oxygen content of fiber per unit volume, and improving the performance of fiber.
[0030] 2. The detection module in this invention uses a lever structure with a fiber winder on one side and a counterweight on the other. Initially, a specific length of fiber is wound around the fiber winder, and the lever is balanced by adjusting the counterweight. The oxygen content of the initial fiber segment after oxidation is detected. Then, the detection module detects subsequent fibers, ensuring that the oxygen content of the fibers during subsequent oxidation processes remains approximately consistent with the oxygen content of the initial fiber segment after oxidation, thus keeping the overall oxygen content of the fibers within a very small error range.
[0031] 3. In this invention, the gas regulation module obtains the regulation signal from the detection module, and the content of oxidizing gas in the oxidation furnace is adjusted based on the regulation signal. In conjunction with the detection module, the oxidation degree of the fiber in the oxidation furnace is adjusted in real time, so that the system can be adjusted quickly and eliminate the lag in the adjustment of the degree of fiber oxidation in the oxidation furnace during the existing fiber system production process.
[0032] 4. The fiber oxidation degree adjustment method disclosed in this invention adds a detection step after the fiber oxidation step, which optimizes the existing fiber preparation process route, makes the difference in oxygen content per unit volume of the prepared fiber small, reduces the defect rate of fiber production, and reduces the fiber preparation cost. Attached Figure Description
[0033] Figure 1 This is a schematic diagram of a fiber oxidation level adjustment system;
[0034] In the attached diagram: 1. First flow controller; 2. Second flow controller; 3. Gas mixer; 4. Oxygen analyzer; 5. Third flow controller; 6. Oxidation furnace; 7. Fiber; 8. Fiber winder; 9. Sensor; 10. Counterweight. Detailed Implementation
[0035] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.
[0036] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0038] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0040] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[0041] See Figure 1 This invention discloses a fiber oxidation degree adjustment system, including an oxidation furnace 6, a detection module, and a gas regulation module:
[0042] The oxidation furnace 6 is used to oxidize the fiber 7, and the working temperature of the oxidation furnace 6 is set between 150 and 400°C. The fiber stays in the oxidation furnace 6 for 60 to 90 minutes. A drafting roller is set at the fiber outlet of the oxidation furnace to pull the fiber out of the oxidation furnace. A detection module is set directly below the drafting roller. The fiber is pulled out of the oxidation furnace by the drafting roller and then hangs down naturally onto the detection module under its own gravity. It then winds around the detection module 5 to 10 times and then enters vertically upwards onto the drafting roller of the next fiber processing step. The speed of the drafting roller in the next fiber processing step is consistent with the rotation speed of the detection module to avoid the drafting roller rotating too fast, which would stretch the fiber wound on the detection module to a set length and affect the detection module's detection of the oxygen content of the fiber wound on the set length, thus affecting the accuracy of real-time detection.
[0043] See Figure 1 The detection module is located directly below the drawing roller at the fiber outlet of the oxidation furnace 6. It is used to detect the oxygen content of the fiber 7 of a set length after oxidation in real time and generate an adjustment signal based on the oxygen content of the fiber 7 of the set length.
[0044] The gas regulation module is located at the air inlet of the oxidation furnace 6 and is used to input mixed gas into the oxidation furnace 6 to supply the oxidation treatment of the fibers 7 inside the oxidation furnace 6. The gas regulation module is communicatively connected to the detection module. The gas regulation module is used to adjust the flow rate and oxygen content of the mixed gas input into the oxidation furnace 6 according to the regulation signal. In this way, the mixed gas input into the oxidation furnace can be adjusted according to the oxygen content in the fiber within a limited length after oxidation treatment. This enables real-time adjustment of the degree of fiber oxidation, improves the fiber preparation system, and allows for real-time monitoring and adjustment of the oxygen content of the fiber during the fiber generation process. This reduces the difference in oxygen content within 1μm of the prepared fiber and the required fiber, improves fiber performance, reduces production costs, and reduces the defect rate of fiber production.
[0045] Furthermore, the detection module includes a fiber winder 8 and a counterweight 10. The fiber winder 8 is positioned directly below the drawing roller at the fiber outlet of the oxidation furnace 6, and the fiber winder 8 is parallel to the axial direction of the drawing roller. One end of the fiber winder 8 is connected to a drive motor, which drives it to rotate at the same speed as the drawing roller. The fiber winder 8 is used to wind fibers 7 to a set length, ensuring that the fibers wound on the fiber winder 8 maintain the set length during fiber preparation. This allows for a direct assessment of the oxygen content of the fiber at that length by observing the change in the weight of the fiber at that length. In other words, by measuring the weight of the fiber 7 at a specific length, the oxygen content of the fiber 7 at that length can be obtained, thus enabling a direct detection of the oxygen content of the fiber 7. The fiber winder 8 is a winding roller with a length of 16cm and a diameter of 30cm. It is driven by a micro motor mounted on the shaft end, and the winding speed is consistent with the fiber exiting the oxidation furnace.
[0046] Furthermore, one end of the lever is connected to the fiber winder 8, and the other end of the lever is connected to the counterweight 10. After the fiber winder 8 initially winds a set length of fiber, a balance fulcrum is set on the lever. By adjusting the position of the counterweight 10 or increasing or decreasing the weight of the counterweight 10, the lever is balanced, and then fiber preparation begins. A sensor 9 is set at the balance fulcrum of the lever. During the fiber preparation process, after the fiber subsequently pulled from the oxidation furnace 6 winds a set length, the lever swings. The sensor 9 is used to obtain the swing signal of the lever when the weight of the fiber 7 wound on the fiber winder 8 changes, generating an adjustment signal (a feedback voltage or current signal generated by the sensor 9). The sensor 9 is communicatively connected to the gas regulation module and transmits the adjustment signal to the gas regulation module. The gas regulation module adjusts the mixed gas input to the oxidation furnace 6 through the adjustment signal. The swing signal includes the swing angle and swing direction of the lever.
[0047] In the above process, if the weight of the fiber wound on the fiber winder 8 increases, the oxygen content in the fiber of that specific length increases, and the fiber winder 8 rotates downward around the lever fulcrum. As a result, one end of the lever located on the counterweight 10 will tilt up, and the lever will swing in the positive direction (the direction in which the fiber winder 8 swings downward on the lever is set as the positive direction). At this time, the sensor 9 generates a first adjustment signal. If the weight of the fiber wound on the fiber winder 8 decreases, the oxygen content in the fiber of that specific length decreases, and the fiber winder 8 rotates upward around the lever fulcrum. As a result, one end of the lever located on the fiber winder 8 will tilt up, and the lever will swing in the opposite direction. At this time, the sensor 9 generates a second adjustment signal.
[0048] See Figure 1The gas regulation module includes a gas mixer 3, which has two air inlets. One air inlet is connected to an oxidizing gas source, and the other air inlet is connected to a rare gas source. By inputting different gas sources through the two air inlets, the gas mixer 3 can mix gases with different oxygen contents.
[0049] Furthermore, the outlet of the gas mixer 3 is connected to the inlet of the oxygen analyzer 4 via a pipeline, and the outlet of the oxygen analyzer 4 is connected to the inlet of the oxidation furnace 6 via a pipeline. The oxygen analyzer 4 is used to obtain the oxygen content information of the mixed gas input to the oxidation furnace 6 based on the oxygen content in the mixed gas output from the gas mixer 3, so as to facilitate the control and adjustment of the amount of oxygen input into the gas mixer 3 and improve the accuracy of fiber oxidation degree adjustment.
[0050] Furthermore, a third flow controller 5 is installed on the connecting pipe between the outlet of the oxygen analyzer 4 and the inlet of the oxidation furnace 6. The third flow controller 5 is communicatively connected to the sensor 9. The third flow controller 5 obtains the adjustment signal from the sensor 9, and then controls the flow rate of the mixed gas input into the oxidation furnace 6 by the gas mixer 3 according to the adjustment signal of the sensor 9, thereby controlling the degree of oxidation of the fiber 7 in the oxidation furnace 6. That is, if the third flow controller 5 obtains the first adjustment signal, it reduces the flow rate of the mixed gas input into the oxidation furnace 6; if the third flow controller 5 obtains the second adjustment signal, it increases the flow rate of the mixed gas input into the oxidation furnace 6.
[0051] Furthermore, a first flow controller 1 is installed on the pipeline connecting the oxidizing gas source and one of the inlets of the gas mixer 3; a second flow controller 2 is installed on the pipeline connecting the rare gas source and the other inlet of the gas mixer 3. The first flow controller 1 and the second flow controller 2 are respectively communicatively connected to a sensor 9. The first flow controller 1, by acquiring the adjustment signal from the sensor 9, adjusts the flow rate of the oxidizing gas input from the oxidizing gas source into the gas mixer 3 according to the adjustment signal, thereby controlling the input amount of the oxidizing gas. The second flow controller 2, by acquiring the adjustment signal from the sensor 9, adjusts the flow rate of the rare gas input from the rare gas source into the gas mixer 3 according to the adjustment signal, thereby controlling the input of the rare gas into the gas mixer 3. The amount of gas input is adjusted so that the oxygen content of the mixed gas in the gas mixer 3 can be adjusted according to the degree of fiber oxidation, thereby controlling the oxygen content input into the oxidation furnace 6. Specifically, if the first flow controller 1 and the second flow controller 2 receive a first adjustment signal, the first flow controller 1 reduces the amount of oxidizing gas input into the gas mixer 3, and the second flow controller 2 increases the amount of rare gas input into the gas mixer 3. If the first flow controller 1 and the second flow controller 2 receive a second adjustment signal, their adjustments are reversed. During the process of adjusting the gas input, the first flow controller 1 and the second flow controller 2 maintain a constant total volume of gas input into the gas mixer 3 per unit time. Simultaneously, the operation of adjusting the flow rate into the oxidation furnace 6 via the third flow controller 5 and the operation of adjusting the oxygen content in the mixed gas via the first flow controller 1 and the second flow controller 2 can be performed individually or simultaneously.
[0052] Furthermore, the oxidizing gas is oxygen; the rare gas is one of nitrogen, argon, or helium; among them, nitrogen is preferred because of its low market price and its similar function to argon or helium in the oxidation furnace.
[0053] Based on the aforementioned fiber oxidation degree adjustment system, this invention also discloses a method for using the system in actual production, the specific operating steps of which are as follows:
[0054] Fiber oxidation preparation and initial fiber segment oxidation:
[0055] Set the temperature of the oxidation furnace to 150℃~400℃ and set 9~12 temperature zones. Adjust the running speed of the fiber in the oxidation furnace to 1.5 m / min~6 m / min. Set the fiber treatment time in the oxidation furnace to 60min~90min. Set the flow rate of the third flow controller to 100~300 LPM. The fiber undergoes initial oxidation.
[0056] Install the detection module and wrap a specific length of fiber around it:
[0057] A detection module is set directly below the drawing roller; after the fiber drawn from the outlet of the oxidation furnace is wound around the fiber winder 5 to 10 times, the end of the fiber is drawn to the drawing rod of the next fiber processing step.
[0058] Adjust the counterweight to balance the lever, begin fiber preparation, and drive the fiber winder to rotate;
[0059] During the fiber preparation process, the swing angle and swing direction of the lever are obtained by the sensor based on the change in fiber density after the fiber winder winds 5 to 10 turns. Based on the swing angle and swing direction of the lever, a real-time adjustment signal for the oxygen content of the fiber at a specific fiber length is generated.
[0060] Specifically, if the lever rotates downward at one end of the fiber winder, a first adjustment signal is generated; if the lever rotates downward at one end of the counterweight, a second adjustment signal is generated.
[0061] The oxygen content of the mixed gas in the oxidation furnace is adjusted in real time based on the control signal, thereby regulating the degree of fiber oxidation.
[0062] The real-time adjustment of the oxygen content of the mixed gas in the oxidation furnace based on the adjustment signal includes: the third flow controller obtains the adjustment signal and adjusts the flow rate of the mixed gas input into the oxidation furnace by the gas mixer; that is, if the third flow controller obtains the first adjustment signal, it reduces the mixed gas input into the oxidation furnace; if the third flow controller obtains the second adjustment signal, it increases the mixed gas input into the oxidation furnace.
[0063] The real-time adjustment of the oxygen content of the mixed gas in the oxidation furnace based on the adjustment signal also includes: the second flow controller and the first flow controller adjusting the proportion in the input gas mixer based on the adjustment signal, changing the oxygen content of the mixed gas in the gas mixer, and inputting it into the oxidation furnace to oxidize the fibers; that is, if the first flow controller and the second flow controller obtain the first adjustment signal, the first flow controller reduces the amount of oxidizing gas in the input gas mixer, and the second flow controller increases the amount of rare gas in the input gas mixer; if the first flow controller and the second flow controller obtain the second adjustment signal, the adjustment of the first flow controller and the second flow controller is reversed. During the process of adjusting the gas input amount, the first flow controller and the second flow controller always maintain the total volume of gas simultaneously input into the gas mixer per unit time without change.
[0064] If the oxygen content of the mixed gas in the oxidation furnace cannot be balanced after adjusting the oxygen content of the fiber of a specific length through the third flow controller, the second flow controller, and the first flow controller, then the two adjustment methods mentioned above are combined and adjusted simultaneously to balance the levers in the detection module.
[0065] Furthermore, when the mixed gas in the gas mixer is fed into the oxidation furnace, an oxygen analyzer is used to detect and verify the oxygen content in the mixed gas.
[0066] Furthermore, the flow rate adjustment range of the third flow controller is 100~300 LPM, and the oxygen content adjustment range in the mixed gas is 10%~30%.
[0067] The above operations can detect the oxygen content of the fiber after oxidation in real time, and adjust the mixed gas input into the oxidation furnace in real time according to the real-time detection results, reduce the gap between the fiber volume of 1μm and the oxygen content, and improve the overall performance of the fiber.
[0068] The above method will be further explained and illustrated below with reference to the embodiments:
[0069] Example 1:
[0070] The oxidation furnace was set to operate at a temperature of 150℃ to 280℃, with six temperature zones ranging from low to high. The fiber running speed was set to 1.5 m / min, the oxygen content of the mixed gas was controlled at 10%, the mixed gas flow rate was 100 LPM, and the fiber processing time in the oxidation furnace was 90 min. After the oxidized fiber was wound 10 times on the fiber winder, it was drawn to the drawing roller of the next fiber processing stage. The resulting oxidized fiber had an oxygen content of 6%, and the final carbon fiber tensile strength was 1800 MPa.
[0071] Example 2:
[0072] The oxidation furnace was set to operate at a temperature of 200℃ to 400℃, with nine temperature zones ranging from low to high. The fiber running speed was set to 6.0 m / min, the oxygen content of the mixed gas was controlled at 30%, the mixed gas flow rate was 300 LPM, and the fiber processing time in the oxidation furnace was 60 min. After the oxidized fiber was wound 10 times on the fiber winder, it was drawn to the drawing roller of the next fiber processing stage. The resulting oxidized fiber had an oxygen content of 10%, and the final carbon fiber tensile strength was 1600 MPa.
[0073] Example 3:
[0074] The oxidation furnace was set to operate at a temperature of 180℃ to 320℃, with 12 temperature zones set from low to high. The fiber running speed was set to 3.0 m / min, the oxygen content of the mixed gas was controlled at 20%, the mixed gas flow rate was 200 LPM, and the fiber processing time in the oxidation furnace was 90 min. After the oxidized fiber was wound 10 times on the fiber winder, it was drawn to the drawing roller of the next fiber processing stage. The resulting oxidized fiber had an oxygen content of 8%, and the final carbon fiber tensile strength was 2400 MPa.
[0075] Through the above embodiments, it can be concluded that the minimum tensile strength of carbon fibers prepared by this system is 1600 MPa, and the tensile strength of carbon fibers can reach 2400 MPa when the oxygen content of the mixed gas is controlled at about 20% and the flow rate of the mixed gas is 200 LPM. Thus, the performance of the prepared carbon fibers is improved.
[0076] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0077] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.
Claims
1. A fiber oxidation degree adjustment system, characterized in that, Includes an oxidation furnace (6), a detection module, and a gas regulation module: The oxidation furnace (6) is used to oxidize the fiber (7); The detection module is located at the fiber outlet of the oxidation furnace (6) and is used to detect the oxygen content of the fiber (7) after oxidation in real time and generate an adjustment signal based on the oxygen content. The detection module includes a fiber winder (8) and a counterweight (10). The fiber winder (8) is located at the filament outlet of the oxidation furnace (6) and is used to wind the fiber (7) N times. The fiber winder (8) is connected to one end of a lever, and the other end of the lever is connected to the counterweight (10). A sensor (9) is provided on the lever. The sensor (9) is used to obtain the swing signal of the lever when the weight of the fiber (7) wound on the fiber winder (8) of a set length changes, and generate the adjustment signal. The sensor (9) is communicatively connected to the gas regulation module and transmits the regulation signal to the gas regulation module; The gas regulation module is located at the air inlet of the oxidation furnace (6) and is used to input mixed gas into the oxidation furnace (6). The gas regulation module is communicatively connected to the detection module and is used to adjust the flow rate of the mixed gas input into the oxidation furnace (6) and the oxygen content in the mixed gas according to the regulation signal.
2. The fiber oxidation degree adjustment system according to claim 1, characterized in that, The gas regulation module includes a gas mixer (3), which has two air inlets, one of which is connected to an oxidizing gas source and the other is connected to a rare gas source. The outlet of the gas mixer (3) is connected to the inlet of the oxygen separator (4), and the outlet of the oxygen separator (4) is connected to the inlet of the oxidation furnace (6).
3. The fiber oxidation degree adjustment system according to claim 2, characterized in that, A third flow controller (5) is provided on the connecting pipe between the outlet of the oxygen analyzer (4) and the inlet of the oxidation furnace (6). The third flow controller (5) is communicatively connected to the sensor (9) and is used to control the flow rate of the mixed gas entering the oxidation furnace (6) according to the adjustment signal.
4. The fiber oxidation degree adjustment system according to claim 2, characterized in that, A first flow controller (1) is provided between the oxidizing gas source and one of the air inlets on the gas mixer (3); a second flow controller (2) is provided between the rare gas source and the other air inlet on the gas mixer (3). The first flow controller (1) and the second flow controller (2) are respectively connected to the sensor (9) for adjusting the flow rate of the gas entering the gas mixer (3) according to the adjustment signal.
5. The fiber oxidation degree adjustment system according to claim 2, characterized in that, The oxidizing gas is oxygen; the rare gas is one of nitrogen, argon or helium.
6. A method for adjusting the degree of fiber oxidation, using the system described in any one of claims 1-5, characterized in that, include: Set the fiber oxidation parameters and oxidize the initial fiber segment; After the oxidized initial fiber segment is wound around the fiber winder to a set length, the end of the fiber is pulled to the next fiber processing step. The counterweight is adjusted to balance the lever, and fiber preparation begins, driving the fiber winder to rotate. In the fiber preparation process, the swing angle and swing direction of the lever are obtained by the sensor based on the change in weight of the fiber wound to a set length on the fiber winder, and an adjustment signal is generated based on the swing angle and swing direction of the lever. The oxygen content of the mixed gas in the oxidation furnace is adjusted in real time based on the adjustment signal, thereby adjusting the degree of fiber oxidation.
7. The method for adjusting the degree of fiber oxidation according to claim 6, characterized in that, The oxygen content of the mixed gas in the oxidation furnace is adjusted in real time based on the adjustment signal, including the third flow controller acquiring the adjustment signal and adjusting the flow rate of the mixed gas input into the oxidation furnace by the gas mixer.
8. The method for adjusting the degree of fiber oxidation according to claim 6, characterized in that, The real-time adjustment of the oxygen content of the mixed gas in the oxidation furnace based on the adjustment signal includes the second flow controller and the first flow controller adjusting the proportion of the input gas mixer based on the adjustment signal, thereby changing the oxygen content of the mixed gas in the gas mixer.
9. The method for adjusting the degree of fiber oxidation according to claim 6, characterized in that, When the mixed gas in the gas mixer is fed into the oxidation furnace, the oxygen content is detected using an oxygen analyzer.
10. The method for adjusting the degree of fiber oxidation according to claim 6, characterized in that, The fiber is wound around the fiber winder 5 to 10 times.