Drying method of carbon fiber precursor

Abstract

The invention discloses a carbon fiber precursor drying method, and relates to the technical field of carbon fiber production. Comprising a pretreatment system, a drying system, a steam spraying system and a cooling and shaping system, the pretreatment system is used for primarily drying the carbon fiber precursor through the pretreatment system to remove redundant moisture on the surface; the drying system comprises a first drying system, a second drying system and a third drying system, is used for uniformly heating the pretreated carbon fiber precursor, and is divided into three drying areas with different temperatures; the steam spraying system is arranged to be used for steam drafting when the drying system dries the carbon fiber precursors; and the cooling and shaping system is used for cooling and shaping the dried and steam-drafted carbon fiber precursors. The drying device has the advantages that the carbon fiber precursors are uniformly heated during drying, the quality of the carbon fiber precursors is remarkably improved, and a powerful guarantee is provided for production of high-performance carbon fibers.

Description

Technical Field

[0001] The invention belongs to the technical field of carbon fiber production, in particular to a method for drying carbon fiber precursor. Background Art

[0002] Carbon fiber is a new type of material with excellent properties such as high strength, high modulus, low density, corrosion resistance and high temperature resistance. It is widely used in aerospace, automobile, sports equipment and other fields. The performance of carbon fiber depends largely on the quality of its precursor. Therefore, improving the preparation quality of carbon fiber precursor is the key to improving the overall performance of carbon fiber.

[0003] During the spinning process, the carbon fiber precursor is dried and densified to remove moisture, making the fiber structure denser, thereby improving its crystallinity and orientation. However, the traditional drying and densification method has some problems, such as heat concentration and small drafting multiples, which will affect the final performance of the precursor.

[0004] In order to solve these problems, the present invention proposes a novel method for drying carbon fiber precursor. The method adopts a gradient heating method to make the precursor experience different temperature changes in different areas, thereby achieving uniform densification and high orientation. Specifically, by introducing a steam spray device during the drying process and steam-drawing the precursor, the drafting multiple can be significantly increased, further improving the densification degree and orientation degree of the precursor.

[0005] In addition, steam drawing technology has a significant effect on improving the orientation and crystallinity of the precursor. Studies have shown that under appropriate steam pressure and temperature, steam drawing can effectively enhance the physical and mechanical properties of the precursor. Therefore, the combination of gradient heating and steam drawing can significantly improve the quality of carbon fiber precursors and provide a strong guarantee for the production of high-performance carbon fibers. Summary of the invention

[0006] To achieve the above object, the present invention adopts the following technical solution: The present invention provides a method for drying carbon fiber precursor, comprising: Pretreatment system, drying system, steam spray system, cooling and shaping system; The pretreatment system is configured to initially dry the carbon fiber precursor through the pretreatment system to remove excess moisture on the surface; The drying system includes a first drying system, a second drying system, and a third drying system, which are configured to uniformly heat the pretreated carbon fiber precursors, and the drying system is divided into three drying zones with different temperatures; The steam spray system is configured to perform steam drawing when the drying system is drying the carbon fiber precursor; The cooling and shaping system is configured to cool and shape the carbon fiber precursor after drying and steam drawing; The first drying system, the second drying system and the third drying system all include a guiding device and a drying hood. A conveying device is provided between the first drying system and the second drying system, and a conveying device is provided between the second drying system and the third drying system. Guide devices are fixedly provided at the inlet and outlet inside the drying hood respectively. A first heating roller is provided at the middle part of the inner side of the drying hood of the first drying system, a second heating roller is provided at the middle part of the inner side of the drying hood of the second drying system, and a third heating roller is provided at the middle part of the inner side of the drying hood of the third drying system. Steam spray ports are provided above the first heating roller, the second heating roller and the third heating roller.

[0007] Furthermore, the pretreatment system includes a hot air blower, an outlet pipe is provided at the outlet end of the hot air blower, a blowing pipe is connected to the end of the outlet pipe, a hot air valve is provided on the blowing pipe, a hot air nozzle is provided at the end of the blowing pipe, the blowing pipe passes through the upper end of the pretreatment hood, and guide devices are fixedly provided at the inlet and outlet inside the pretreatment hood.

[0008] Furthermore, a steam pipe is provided at the upper end of the drying hood, a bracket is provided at the lower end of the drying hood, one end of the first heating roller is connected to the motor, the other end of the first heating roller is connected to the first temperature regulating cabinet, the other end of the second heating roller is connected to the second temperature regulating cabinet, and the other end of the third heating roller is connected to the third temperature regulating cabinet.

[0009] Furthermore, the steam spray system includes a steam generating device, a steam exhaust pipe is provided at the top of the steam generating device, a steam valve is provided on the steam exhaust pipe, a steam main pipe is provided at the end of the steam exhaust pipe, a steam pipe is provided on the steam main pipe, and a steam spray port is provided at the end of the steam pipe.

[0010] Furthermore, the cooling and shaping system includes a cold air blower, a cold air outlet pipe is provided at the outlet end of the cold air blower, a cold air blowing pipe is connected to the end of the cold air outlet pipe, a cold air valve is provided on the cold air blowing pipe, a cold air nozzle is provided at the end of the cold air blowing pipe, the cold air blowing pipe passes through the upper end of the cooling hood, and guide devices are fixedly provided at the inlet and outlet on the inner side of the cooling hood.

[0011] A method for drying carbon fiber precursor using the above device comprises the following steps: S1: firstly set the temperature of the first heating roller of the first drying system to 100°C, the temperature of the second heating roller of the second drying system to 120°C, the temperature of the third heating roller of the third drying system to 140°C, and start the steam spraying system; S2: Carbon fiber precursor is transported to the pretreatment system through a conveying device; S3: The carbon fiber precursors from the pretreatment system enter the first drying system along the guide device; S4: After the first drying system completes drying, it enters the second drying system through the conveying device; S5: After the second drying system completes drying, it enters the third drying system through the conveying device; S6: After the third drying system completes drying, it enters the cooling and shaping system through the conveying device.

[0012] The advantages of the present invention are as follows: in the present invention, through the mutual cooperation of the first drying system, the second drying system, the third drying system and the steam spray system with gradient heating, the gradient heating system ensures that the carbon fiber precursor is heated evenly in different areas, avoiding quality problems caused by uneven temperature, and the steam drawing technology significantly improves the drawing multiple of the precursor and enhances the strength and modulus of the fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a structural schematic diagram of the pretreatment system of the present invention; Figure 3 Schematic diagram of the internal structure of the pretreatment system of the present invention; Figure 4 It is a structural schematic diagram of the first drying system of the present invention; Figure 5 It is a schematic diagram of the connection structure of the drying system of the present invention; Figure 6 It is a structural schematic diagram of the steam spray system of the present invention; Figure 7 It is a schematic diagram of the structure of the cooling and shaping system of the present invention.

[0014] Legend: 1-pretreatment system, 101-hot air blower, 102-air outlet pipe, 103-blowing pipe, 104-hot air valve, 105-pretreatment cover, 106-hot air nozzle, 2-drying system, 201-first drying system, 2010-drying cover, 2011-motor, 2012-first heating roller, 2013-bracket, 2014-first temperature regulating cabinet, 202-second drying system, 2022-second heating roller, 2024-second temperature regulating cabinet, 203-third drying system, 2032-the third heating roller, 2034-the third temperature regulating cabinet, 3-steam spray system, 301-steam spray port, 302-steam pipe, 303-steam main pipe, 304-steam valve, 305-steam exhaust pipe, 306-steam generating device, 4-cooling and shaping system, 401-air cooler, 402-cold air outlet pipe, 403-cold air blowing pipe, 404-cold air valve, 405-cooling hood, 406-cold air nozzle, 5-conveying device, 6-guiding device. DETAILED DESCRIPTION

[0015] The content of the present invention is further described below in conjunction with the examples. The examples are not intended to limit the scope of protection of the present invention. Without departing from the essence of the technical solution of the present invention, modifications or substitutions made to the method, steps or conditions of the present invention all belong to the scope of the present invention.

[0016] Unless otherwise specified, the equipment, devices and process methods used in the examples are conventional equipment, devices and process methods well known to those of ordinary skill in the art.

[0017] The specific implementation of the present invention will be described below with a preferred embodiment of the present invention: like Figure 1 , as shown in the overall structural diagram of an embodiment of the present invention, the embodiment includes a pretreatment system 1, a drying system 2, a steam spraying system 3, and a cooling and shaping system 4; like Figure 2 and Figure 3 As shown in the schematic diagram of a pretreatment system 1 according to an embodiment of the present invention, the pretreatment system 1 is configured to preliminarily dry the carbon fiber precursor through the pretreatment system to remove excess surface moisture, and includes a hot air blower 101, an outlet end of the hot air blower 101 is provided with an air outlet pipe 102, the end of the air outlet pipe 102 is connected to a blowing pipe 103, a hot air valve 104 is provided on the blowing pipe 103, a hot air nozzle 106 is provided at the end of the blowing pipe 103, the blowing pipe 103 passes through the upper end of a pretreatment cover 105, and guide devices 6 are fixedly provided at the inlet and outlet of the inner side of the pretreatment cover 105; The carbon fiber raw yarn is delivered to the pretreatment hood 105 via the conveying device 5, enters the pretreatment hood 105 along the guide device 6, is output after passing through the guide device 6 at the outlet, and then passes through the inside of the treatment hood 105. The hot air nozzle 106 above performs preliminary removal of residual solvents and impurities on the surface of the carbon fiber yarn passing through.

[0018] like Figure 4 and Figure 5 As shown in the schematic diagram of the first drying system 201 of an embodiment of the present invention, the first drying system 201, the second drying system 202, and the third drying system 203 all include a guiding device 6, a drying cover 2010, a conveying device 5 is provided between the first drying system 201 and the second drying system 202, and a conveying device 5 is provided between the second drying system 202 and the third drying system 203. The guiding devices 6 are fixedly provided at the inlet and outlet of the inner side of the drying cover 7, a first heating roller 2012 is provided at the middle of the inner side of the drying cover 2010 of the first drying system 201, a second heating roller 2022 is provided at the middle of the inner side of the drying cover 2010 of the second drying system 202, and a third heating roller 2032 is provided at the middle of the inner side of the drying cover 2010 of the third drying system 203. The first heating roller 2012, the second heating roller 20 A steam spray port 301 is provided above each of the first heating roller 2012 and the third heating roller 2032. One end of the first heating roller 2012 is connected to the motor 2011, and the other end of the first heating roller 2012 is connected to the first temperature regulating cabinet 2014. The other end of the second heating roller 2022 is connected to the second temperature regulating cabinet 2024. The other end of the third heating roller 2032 is connected to the third temperature regulating cabinet 2034. The temperatures of the first heating roller 2012, the second heating roller 2022 and the third heating roller 2032 can be set by the first temperature regulating cabinet 2014, the second temperature regulating cabinet 2024 and the third temperature regulating cabinet 2034. While the carbon fiber precursor is uniformly heated on the first heating roller 2012, the second heating roller 2022 and the third heating roller 2032, the steam from the steam spray port 301 steam-stretches the carbon fiber precursor. The first drying system 201, the second drying system 202, and the third drying system 203 are configured to uniformly heat the pretreated carbon fiber precursors. The drying system 2 is divided into three drying zones with different temperatures.

[0019] like Figure 6 As shown in the schematic diagram of a steam spray system 3 according to an embodiment of the present invention, the steam spray system 3 includes a steam generating device 306, a steam discharge pipe 305 is provided at the top of the steam generating device 306, a steam valve 304 is provided on the steam discharge pipe 305, a steam main pipe 303 is provided at the end of the steam discharge pipe 305, a steam pipe 302 is provided on the steam main pipe 303, and a steam spray port 301 is provided at the end of the steam pipe 302; The steam spray system 3 is configured to perform steam drawing when the drying system 2 is drying the carbon fiber precursor.

[0020] like Figure 7 A cooling and shaping system 4 according to an embodiment of the present invention comprises a cooling air machine 401, a cold air outlet pipe 402 is provided at the outlet end of the cooling air machine 401, a cold air blowing pipe 403 is connected to the end of the cold air outlet pipe 402, a cold air valve 404 is provided on the cold air blowing pipe 403, a cold air nozzle 406 is provided at the end of the cold air blowing pipe 403, the cold air blowing pipe 403 passes through the upper end of a cooling hood 405, and guide devices 6 are fixedly provided at the inlet and outlet of the inner side of the cooling hood 405, respectively.

[0021] The cooling and shaping system 4 is configured to cool and shape the carbon fiber precursor after drying and steam drawing.

[0022] Next, a method for drying carbon fiber precursor provided by the present invention is described in conjunction with a preferred embodiment of the present invention: S1: First, we set the temperature of the first heating roller 2012 in the first drying system 201 to 100°C. Then, we adjust the temperature of the second heating roller 2022 in the second drying system 202 to 120°C. Finally, in order to ensure that the carbon fiber material can be fully dried and not damaged, we adjust the temperature of the third heating roller 2032 in the third drying system 203 to 140°C. After completing the temperature settings of all the heating rollers above, start the steam spray system 3 to provide spray steam, which is crucial to maintaining the fiber quality in the subsequent processing process.

[0023] S2: When everything is ready, the carbon fiber precursor to be treated is smoothly fed into the pretreatment system 1 through the conveying device 5. This step is to remove surface impurities and improve its physical properties, laying a good foundation for the subsequent high-temperature treatment.

[0024] S3: The pre-treated carbon fiber precursor will smoothly enter the first drying system 201 along the guide device 6. Here, it is preliminarily heated and dried by the preheated first heating roller 2012. This process helps to further remove moisture and possible defects such as tiny bubbles. The spray system 3 simultaneously sprays steam on the drying carbon fiber precursor.

[0025] S4: After the first drying stage is finished, the semi-dried carbon fiber precursor is transferred to the next workstation, namely the second drying system 202, through another set of conveying devices 5. Here, the second heating roller 2022 at 120°C will further dry the carbon fiber precursor, and steam spray will be introduced to promote the rapid evaporation of the residual moisture inside, while enhancing the stability of the fiber structure.

[0026] S5: Afterwards, the completely dried carbon fiber precursor continues to move forward and is sent to the final stage working unit, the third drying system 203, via the equally reliable conveying device 5. At this time, the third heating roller 2032 at 140°C finally dries the carbon fiber precursor in order to completely solidify its shape and maximize its strength and durability.

[0027] S6: Finally, after going through three different levels of closely connected heat treatment processes, high-quality carbon fiber products will be output from the third drying system 203 and quickly cooled by the dedicated cooling and shaping system 4. This can not only prevent product deformation or damage caused by excessive temperature differences, but also ensure that the finished product has good dimensional accuracy and consistency. At this point, the operation of the entire production line has come to an end, and carbon fiber precursor products that meet high standards have been obtained.

Claims

1. A method for drying carbon fiber precursor, characterized in that: include Pretreatment system (1), drying system (2), steam spraying system (3), cooling and shaping system (4); The pretreatment system (1) is configured to initially dry the carbon fiber precursor through the pretreatment system to remove excess moisture on the surface; The drying system (2) comprises a first drying system (201), a second drying system (202), and a third drying system (203), and is configured to uniformly heat the pretreated carbon fiber precursors. The drying system (2) is divided into three drying zones with different temperatures. The steam spray system (3) is configured to perform steam drawing when the drying system (2) is drying the carbon fiber precursor; The cooling and shaping system (4) is configured to cool and shape the carbon fiber precursor after drying and steam drawing; The first drying system (201), the second drying system (202) and the third drying system (203) all comprise a guiding device (6) and a drying hood (2010); a conveying device (5) is arranged between the first drying system (201) and the second drying system (202); a conveying device (5) is arranged between the second drying system (202) and the third drying system (203); guiding devices (6) are fixedly arranged at the inlet and outlet of the inner side of the drying hood (7); a first heating roller (2012) is arranged at the middle part of the inner side of the drying hood (2010) of the first drying system (201); a second heating roller (2022) is arranged at the middle part of the inner side of the drying hood (2010) of the second drying system (202); a third heating roller (2032) is arranged at the middle part of the inner side of the drying hood (2010) of the third drying system (203); and steam spraying ports (301) are arranged above the first heating roller (2012), the second heating roller (2022) and the third heating roller (2032).

2. The method for drying carbon fiber precursor according to claim 1, characterized in that The pretreatment system (1) comprises a hot air blower (101), an outlet end of the hot air blower (101) is provided with an air outlet pipe (102), the end of the air outlet pipe (102) is connected to a blowing pipe (103), a hot air valve (104) is provided on the blowing pipe (103), a hot air nozzle (106) is provided at the end of the blowing pipe (103), the blowing pipe (103) passes through the upper end of the pretreatment hood (105), and guide devices (6) are fixedly provided at the inlet and outlet of the inner side of the pretreatment hood (105).

3. The method for drying carbon fiber precursor according to claim 1, characterized in that The upper end of the drying hood (2010) is provided with a steam pipe (302) passing through it, the lower end of the drying hood (2010) is provided with a bracket (2013), one end of the first heating roller (2012) is connected to the motor (2011), the other end of the first heating roller (2012) is connected to the first temperature regulating cabinet (2014), the other end of the second heating roller (2022) is connected to the second temperature regulating cabinet (2024), and the other end of the third heating roller (2032) is connected to the third temperature regulating cabinet (2034).

4. The method for drying carbon fiber precursor according to claim 1, characterized in that The steam spray system (3) comprises a steam generating device (306), a steam discharge pipe (305) is arranged at the top of the steam generating device (306), a steam valve (304) is arranged on the steam discharge pipe (305), a steam main pipe (303) is arranged at the end of the steam discharge pipe (305), a steam pipe (302) is arranged on the steam main pipe (303), and a steam spray port (301) is arranged at the end of the steam pipe (302).

5. The method for drying carbon fiber precursor according to claim 1, characterized in that The cooling and shaping system (4) comprises a cold air blower (401), the outlet end of the cold air blower (401) is provided with a cold air outlet pipe (402), the end of the cold air outlet pipe (402) is connected to a cold air blowing pipe (403), a cold air valve (404) is provided on the cold air blowing pipe (403), a cold air nozzle (406) is provided at the end of the cold air blowing pipe (403), the cold air blowing pipe (403) passes through the upper end of the cooling cover (405), and guide devices (6) are fixedly provided at the inlet and outlet of the inner side of the cooling cover (405).

6. A method for drying carbon fiber precursor, comprising: S1: firstly, the temperature of the first heating roller (2012) of the first drying system (201) is set to 100°C, the temperature of the second heating roller (2022) of the second drying system (202) is set to 120°C, the temperature of the third heating roller (2032) of the third drying system (203) is set to 140°C, and the steam spraying system (3) is turned on; S2: The carbon fiber precursor is transported to the pretreatment system (1) through a transport device (5); S3: the carbon fiber precursors coming out of the pretreatment system (1) enter the first drying system (201) along the guide device (6); S4: After the drying is completed in the first drying system (201), the dried product enters the second drying system (202) through the conveying device (5); S5: After the second drying system (202) completes drying, it enters the third drying system (203) through the conveying device (5); S6: After the third drying system (203) completes drying, the product enters the cooling and shaping system (4) through the conveying device (5).

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