A carbon fiber preform high pressure impregnation pressurized carbonization process and equipment

Abstract

The present invention relates to a carbon fiber preform high-pressure impregnation pressurized carbonization process and equipment. The equipment includes an outer liner and an inner liner. A cavity is formed between the inner liner and the outer liner. The carbon fiber preform is placed in the cavity. The pressure and temperature in the cavity are controlled by pressure and temperature control to complete integrated high-pressure impregnation and pressurized carbonization. The process includes preform weaving, impregnation liquid preparation, impregnation liquid addition, high-pressure impregnation, pressurized carbonization and product discharge. The method provided by the present invention does not require vapor deposition densification. By optimizing the impregnation liquid, the production process can be completed by one-step high-pressure impregnation and two-step pressurized carbonization. The product cycle is less than 45 days, and the product density is greater than 1.50g / cm 3 The equipment provided is designed in an integrated manner, which is scientific and reasonable and greatly reduces energy consumption.

Description

Technical Field

[0001] The invention relates to the field of carbon material preparation, and in particular to a high-pressure impregnation and pressurized carbonization process and equipment for a carbon fiber preform. Background Art

[0002] Carbon / carbon crucible is an essential consumable for pulling single crystal silicon in the photovoltaic industry. At present, the domestic method of making carbon / carbon crucible is to vapor-deposit the carbon fiber preform to increase the density to 1.0g / cm 3 After impregnation in the impregnation equipment, it is transferred to another equipment for carbonization and densification. The impregnation and carbonization steps are repeated 4-5 times to make the product density reach 1.5g / cm 3 As mentioned above, the entire production cycle takes 90 days, the production processes are complicated and inefficient, there is a lot of energy loss, and the degree of automation is low.

[0003] In view of the above problems, CN104446588A in the prior art discloses a method for liquid phase impregnation densification of a carbon fiber preform, which includes an impregnation step, a low temperature treatment step and a high temperature carbonization step. The carbon fiber preform is used as a reinforcement, and high temperature modified asphalt is used as a matrix impregnating agent. A pressurized impregnation device is used to perform liquid phase impregnation densification treatment of the C / C material. The existing liquid phase impregnation method is used to achieve a C / C material density of 1.5 g cm -3 The above process requires 8 to 10 cycles of densification.

[0004] Although the above technical solution shortens the number of cycles, it cannot solve the problem of long single cycles and complex processes that require equipment replacement. Therefore, it is urgent to invent a new process method to meet the requirements of shortening the production cycle and improving efficiency without affecting product quality. Summary of the invention

[0005] The purpose of the present invention is to solve the problems existing in the prior art, to provide a high-pressure impregnation and pressurized carbonization process for a carbon fiber preform, and to provide equipment for implementing the process.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] The present invention provides a high-pressure impregnation and pressurized carbonization device for a carbon fiber preform, which comprises an outer liner and an inner liner that cooperate with each other, wherein the upper ends of the outer liner and the inner liner are open, and a sealed cavity for placing the carbon fiber preform is formed between the two; an outer shell is arranged on the outer side of the outer liner, a heat-insulating material is arranged inside the outer shell, and an electric heating tube is arranged between the outer side of the outer liner and the heat-insulating material; an upper cover is arranged on the upper end of the inner liner, a heat-insulating material is arranged on the inner side of the upper cover, and an electric heating tube is arranged on the inner side of the inner liner; the sealed cavity is connected to a pressure regulating chamber through a ventilation pipeline, and an automatic pressure relief control valve, an automatic pressurization control valve and a pressure gauge are arranged on the pressure regulating chamber; the sealed cavity is connected to an impregnation liquid pool through a liquid inlet pipeline, and a high-pressure pump and an electric valve are arranged on the liquid inlet pipeline.

[0008] As a further improvement of the present invention, temperature sensors are provided between the outer side of the outer liner and the heat-insulating material and inside the inner liner.

[0009] As a further improvement of the present invention, the outer shell and the upper cover are both provided with temperature control instruments, and the temperature control instruments are electrically connected to temperature sensors arranged between the outer side of the outer liner and the thermal insulation material and the inner side of the inner liner, respectively.

[0010] As a further improvement of the present invention, the upper ends of the outer liner and the inner liner are both provided with an annular outer edge, and the outer edges of the outer liner and the inner liner are provided with corresponding threaded holes, and the outer liner and the inner liner are connected together by connecting bolts.

[0011] As a further improvement of the present invention, a sealing ring is provided between the outer edge of the outer container and the outer edge of the inner container.

[0012] As a further improvement of the present invention, the sealing ring is made of high temperature resistant aluminum silicate fiber felt.

[0013] As a further improvement of the present invention, a vent connected to the vent pipeline is provided at the top of the sealed cavity, and an impregnation liquid inlet connected to the liquid inlet pipeline is provided at the bottom of the sealed cavity.

[0014] As a further improvement of the present invention, the gap at any point of the sealed cavity is 2-3 mm larger than the thickness of the carbon fiber preform described herein.

[0015] As a further improvement of the present invention, the thermal insulation material is rock wool.

[0016] Another aspect of the present invention provides a process for high-pressure impregnation and pressurized carbonization of a carbon fiber preform using the above-mentioned device, which comprises the following steps:

[0017] (1) Preform weaving: Use T700 raw silk to produce carbon cloth and mesh tire, calculate the amount according to size density, cross-layer weaving, 30 needles / cm 2 , obtaining a carbon fiber preform;

[0018] (2) Preparation of impregnation solution: add 0.5-1.0 wt% of one-dimensional or two-dimensional nanocarbon material to coal tar pitch, heat and mix evenly, and set aside;

[0019] (3) High-pressure impregnation: The impregnation solution prepared in step (2) is added according to the density of the carbon fiber preform from 0.45 g / cm 3 Increase to 1.5g / cm 3 Add the calculated amount to immerse the carbon fiber preform, and keep it at 140~160℃ for 1~2h under 5~8MPa;

[0020] (4) Pressurized carbonization: After the treatment in step (3) is completed, the pressure is reduced to 2-4 MPa, and the temperature is programmed to 850±10°C for carbonization for 3-4 h. The programmed temperature curve is as follows: heating to 230°C for 3 h; 230°C for 2 h; 230 to 650°C for 18 h; 650 to 850°C for 9 h; 850°C for 4 h;

[0021] (5) Product removal: Cool down to room temperature, reduce pressure to atmospheric pressure, take out the carbon fiber preform, and you are done.

[0022] As some embodiments of the present invention, the softening point of the coal tar pitch in step (2) is 90-100° C., and the coking value is greater than 45%.

[0023] As some embodiments of the present invention, the mixing temperature in step (2) is 150-180° C., and ultrasonic mixing is used.

[0024] The beneficial effects of adopting the above technical solution are:

[0025] The method provided by the present invention does not require the use of vapor deposition densification. By optimizing the impregnation liquid, the production process can be completed through one step of high-pressure impregnation and two steps of pressurized carbonization. The product cycle is less than 10 days, and the product density is greater than 1.5g / cm 3 .

[0026] The carbon fiber preform high-pressure impregnation and pressurized carbonization integrated machine provided by the present invention does not need to adopt vapor deposition densification, and can complete the high-pressure impregnation and pressurized carbonization processes on one device. Automatic control and safe production are realized through pressure gauges and temperature control instruments, and rapid densification and carbonization are achieved, which reduces production processes, reduces energy consumption, improves production efficiency, and can ensure that the internal structure of the product is uniform, thereby increasing the service life of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a structural schematic diagram of the present invention.

[0029] Wherein: 1 outer liner, 1-1 impregnation liquid inlet, 2 inner liner, 2-1 vent, 3 sealed cavity, 4 carbon fiber preform, 5 outer shell, 6 upper cover, 7 insulation material, 8 electric heating pipe, 9 ventilation pipeline, 10 pressure regulating chamber, 11 automatic pressure relief control valve, 12 automatic pressurization control valve, 13 pressure gauge, 14 liquid inlet pipeline, 15 impregnation liquid pool, 16 high-pressure pump, 17 electric valve, 18 temperature control instrument, 19 connecting bolts, 20 sealing ring, 21 power lead. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is clearly and completely described below in conjunction with specific embodiments.

[0031] Example 1

[0032] A carbon fiber preform high pressure impregnation pressurized carbonization device, such as Figure 1 As shown, it includes an outer liner 1 and an inner liner 2 made of metal materials that cooperate with each other. The outer liner 1 and the inner liner 2 are cylindrical and open at the upper ends, and a sealed cavity 3 for placing a carbon fiber preform 4 is formed between the two. The gap at any point of the sealed cavity 3 is 2-3mm larger than the thickness of the carbon fiber preform 4 described here, ensuring that the carbon fiber preform 4 does not undergo excessive deformation, thereby playing a role in fixing the shape.

[0033] The outer side of the outer liner 1 is provided with a metal shell 5, and the inner side of the outer liner 5 is provided with a heat-insulating material 7, and an electric heating tube 8 is provided between the outer side of the outer liner 1 and the heat-insulating material 7; the upper end of the inner liner 2 is provided with a metal cover 6, and the inner side of the cover 6 is provided with a heat-insulating material 7, and the inner side of the inner liner 2 is provided with an electric heating tube 8. The heat-insulating material 7 is made of rock wool. Temperature sensors are provided between the outer side of the outer liner 1 and the heat-insulating material 7 and inside the inner liner 2. The outer liner 1 and the cover 6 are provided with a temperature control instrument 18, and the temperature control instrument 18 is electrically connected to the temperature sensors provided between the outer side of the outer liner 1 and the heat-insulating material 7 and inside the inner liner 1, respectively. The sealed cavity 3 is connected to the pressure regulating chamber 10 through the ventilation pipeline 9. The pressure regulating chamber 10 is a cavity made of forged steel material and is connected to an air pump. The pressure regulating chamber 10 is provided with an automatic pressure relief control valve 11, an automatic pressurization control valve 12 and a pressure gauge 13, and a pressure transmitter and a safety valve can also be provided. The electric heating tube 8 is evenly arranged along the outer side of the outer liner 1 and the inner side of the inner liner 2, and radiates heat energy to the outer liner 1 and the inner liner 2, and then transfers it to the carbon fiber preform 4 in the sealed cavity 3 by heat conduction to heat it. The temperature in the sealed cavity 3 is regulated by the temperature sensor and the temperature control instrument 18 to ensure that it is maintained at the temperature required by the process. The pressure in the sealed cavity 3 is regulated by the pressure regulating chamber 10 and the pressure gauge 12 to ensure that it is maintained at the pressure required by the process.

[0034] The sealed cavity 3 is connected to the impregnation liquid pool 15 through a liquid inlet pipeline 14, and a high-pressure pump 16 and an electric valve 17 are provided on the liquid inlet pipeline 14. The impregnation liquid pool 15 contains a measured volume of impregnation liquid, which is just enough to completely immerse the carbon fiber preform 4. The impregnation liquid is pumped into the sealed cavity 3 through the high-pressure pump 16, and then the electric valve 17 is closed.

[0035] The outer liner 1 and the inner liner 2 are both provided with an annular outer edge at their upper ends, and corresponding threaded holes are provided on the outer edges of the outer liner 1 and the inner liner 2, and the outer liner 1 and the inner liner 2 are connected together by connecting bolts 19. A sealing ring 20 is provided between the outer edge of the outer liner 1 and the outer edge of the inner liner 2 to seal and prevent air and liquid leakage. The sealing ring 20 is made of high temperature resistant aluminum silicate fiber felt.

[0036] A vent 2-1 connected to the ventilation pipeline 9 is provided at the top of the sealed cavity 3, and the vent 2-1 is opened on the outer edge of the inner tank 2; an impregnation liquid inlet 1-1 connected to the liquid inlet pipeline 14 is provided at the bottom of the sealed cavity 3, and the impregnation liquid inlet 1-1 is opened at the bottom of the outer tank 1.

[0037] The working process of the above device is as follows:

[0038] Preform weaving: Use T700 carbon fiber yarn to produce carbon cloth and mesh tire. Calculate the amount of carbon cloth and mesh tire according to size and density. 2 The carbon fiber preform is obtained by cross-weaving.

[0039] Preparation of impregnation liquid: add 0.5-1.0wt% of one-dimensional nanocarbon material or two-dimensional nanocarbon material to coal tar pitch with a softening point of 95°C and a coking value greater than 45%, mix them evenly at 150-180°C with an ultra-high sound wave frequency of 30Khz, and inject them into the impregnation liquid pool 15 after mixing evenly.

[0040] Product loading: clean the outer liner 1, place the prepared carbon fiber preform 4 on the inner side of the outer liner 1, insert the inner liner 2 into the outer liner 1, and fix the outer edges of the outer liner 1 and the inner liner 2 by the connecting bolts 19 to form a sealed cavity 3 filled with the carbon fiber preform 4, and complete the loading of the product to be processed.

[0041] Pumping in the impregnation liquid: Start the high-pressure pump 16 and pump the impregnation liquid with a residual carbon rate of 45% from 0.45 g / cm 3 Increase to 1.5g / cm 3 The calculated amount is added into the sealing chamber 3, and then the electric valve 17 is automatically closed and the high-pressure pump 16 is automatically stopped.

[0042] High-pressure impregnation: Start automatic heating, introduce electric energy into the electric heating tube 8 through the power lead 21, and start heating to 140~160℃. The temperature is monitored by the temperature control instrument 18. The insulation time is 1~2 hours, so that the impregnation liquid is fully and evenly distributed inside the sealed cavity 3, and automatic heating, insulation and cooling are achieved. During the heating process, gas is generated due to the volatilization of the impregnation liquid, causing the pressure in the enclosed space to increase. Through the detection of the pressure gauge 13 and the control of the PLC control system, the automatic pressure relief control valve 11 is automatically started to control the pressure within the range of 5~8MPa required by the process.

[0043] Pressurized carbonization: After the high-pressure impregnation process is completed, the temperature is kept at 850°C for 4 hours as required by the carbonization process curve described in Example 1, and the temperature is automatically increased, kept and cooled. During this period, the gas generated by volatilization will cause the pressure in the enclosed space to increase. The automatic pressure relief control valve 11 is automatically started through the pressure gauge 13 detection and the PLC control system control to control the pressure within the range of 2~4MPa required by the process until the carbonization process is completed.

[0044] Product out of the oven: the pressure is reduced to "zero" through the automatic pressure relief control valve 11, so that the air pressure in the sealed cavity 3 is the same as the external atmospheric pressure, the connecting bolts 19 are unscrewed, the inner liner 2 and the carbon fiber preform 4 are taken out, and the product is out of the oven.

[0045] Example 2

[0046] The process of high-pressure impregnation and pressurized carbonization of a carbon fiber preform using the equipment described in Example 1 includes the following steps and parameters:

[0047] (1) Preform weaving: Use T700 raw silk to produce carbon cloth and mesh tire. Calculate the amount of carbon cloth and mesh tire according to size density. Carbon cloth is 30 needles / cm 2 The carbon fiber preform is obtained by cross-weaving.

[0048] (2) Preparation of impregnation solution: Add 0.8 wt% of one-dimensional nanocarbon material to coal tar pitch with a softening point of 95°C and a coking value greater than 45%, and mix them by ultrasonication at 165°C with an ultra-high sound wave frequency of 30 kHz.

[0049] (3) High-pressure impregnation: The impregnation solution prepared in step (2) is added to the carbon fiber preform according to step (1) from 0.45 g / cm 3 Increase to 1.5g / cm 3 The calculated amount of is added to immerse the carbon fiber preform, and the temperature is kept at 150°C for 1.5h under 6.5MPa, and then cooled to room temperature;

[0050] (4) Pressurized carbonization: After the treatment in step (3) is completed, the pressure is reduced to 2.0 MPa, and the temperature is programmed to 850°C for carbonization for 4 hours. The programmed temperature rise curve is as follows: heating to 230°C, 3 hours; 230°C, 2 hours; 230 to 650°C, 18 hours; 650 to 850°C, 9 hours; 850°C, 4 hours.

[0051] (5) Product removal: Cool down to room temperature, reduce pressure to atmospheric pressure, take out the carbon fiber preform, and you are done.

[0052] Example 3

[0053] The process of high-pressure impregnation and pressurized carbonization of a carbon fiber preform using the equipment described in Example 1 includes the following steps and parameters:

[0054] (1) Preform weaving: Use T700 raw silk to produce carbon cloth and mesh tire. Calculate the amount of carbon cloth and mesh tire according to size density, and use 30 needles / cm 2 The carbon fiber preform is obtained by cross-weaving.

[0055] (2) Preparation of impregnation solution: Add 1.0 wt% of two-dimensional nanocarbon material to coal tar pitch with a softening point of 95°C and a coking value greater than 45%, and mix them by ultrasonication at 165°C with an ultra-high sound wave frequency of 25 kHz.

[0056] (3) High-pressure impregnation: The impregnation solution prepared in step (2) is added to the carbon fiber preform according to step (1) from 0.45 g / cm 3 Increase to 1.5g / cm3 The calculated amount of was added to immerse the carbon fiber preform, and the temperature was kept at 160℃ for 1h under 5.0MPa, and then cooled to room temperature;

[0057] (4) Pressurized carbonization: After the treatment in step (3) is completed, the pressure is reduced to 3.5 MPa, and the temperature is programmed to 850°C for carbonization for 4 hours. The programmed temperature rise curve is as follows: the temperature is raised to 230°C for 3 hours; 230°C for 2 hours; 230 to 650°C for 18 hours; 650 to 850°C for 9 hours; 850°C for 4 hours.

[0058] (5) Product removal: Cool down to room temperature, reduce pressure to atmospheric pressure, take out the carbon fiber preform, and you are done.

[0059] Example 4

[0060] A high-pressure impregnation and pressurized carbonization process for a carbon fiber preform is produced according to the equipment in Example 2, and the specific parameters are as follows:

[0061] (1) Preform weaving: Use T700 raw silk to produce carbon cloth and mesh tire. Calculate the amount of carbon cloth and mesh tire according to size density, and use 30 needles / cm 2 The carbon fiber preform is obtained by cross-weaving.

[0062] (2) Preparation of impregnation solution: Add 0.5 wt% of two-dimensional nanocarbon material to coal tar pitch with a softening point of 95°C and a coking value greater than 45%, and mix them by ultrasonication at 165°C with an ultra-high sound wave frequency of 30 kHz.

[0063] (3) High-pressure impregnation: The impregnation solution prepared in step (2) is added to the carbon fiber preform according to step (1) from 0.45 g / cm 3 Increase to 1.5g / cm 3 The calculated amount of was added to immerse the carbon fiber preform, and the temperature was kept at 140℃ for 1.5h under 8.0MPa, and then cooled to room temperature;

[0064] (4) Pressurized carbonization: After the treatment in step (3) is completed, the pressure is reduced to 2.0 MPa, and the temperature is programmed to 850°C for carbonization for 4 hours. The programmed temperature rise curve is as follows: heating to 230°C, 3 hours; 230°C, 2 hours; 230 to 650°C, 18 hours; 650 to 850°C, 9 hours; 850°C, 4 hours.

[0065] (5) Product removal: Cool down to room temperature, reduce pressure to atmospheric pressure, take out the carbon fiber preform, and you are done.

[0066] Comparative Example 1

[0067] The difference from Example 2 is that no one-dimensional nano-carbon material is added to the impregnation solution.

[0068] Comparative Example 2

[0069] The difference from Example 2 is that the pressure in the high-pressure impregnation step is 3.0 MPa, and the pressure in the pressurized carbonization step is 1 MPa.

[0070] Effect Example 1

[0071] The products obtained in Example 2, Example 3, Example 4, Comparative Example 1 and Comparative Example 2 were subjected to performance tests on the degree of graphitization, tensile strength, thermal conductivity and thermal diffusivity, as shown in Table 1.

[0072] Table 1 Performance

[0073]

[0074] The process provided by the present invention not only shortens the production cycle by 90% and improves production efficiency, but also obtains products with excellent performance, which can ensure uniform internal structure of the products and increase product service life. According to the current average annual use of 30,000 crucibles in the domestic monocrystalline silicon industry, the production cost can be reduced by at least 110 million yuan per year, prompting the photovoltaic industry to continuously reduce costs and quickly achieve grid parity.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A carbon fiber preform high pressure impregnation pressurized carbonization device, characterized in that: The invention comprises an outer liner (1) and an inner liner (2) which cooperate with each other, wherein the upper ends of the outer liner (1) and the inner liner (2) are open, and a sealed cavity (3) for placing a carbon fiber preform (4) is formed between the two; an outer shell (5) is provided on the outer side of the outer liner (1), and a heat-insulating material (7) is provided inside the outer shell (5); an electric heating tube (8) is provided between the outer side of the outer liner (1) and the heat-insulating material (7); an upper cover (6) is provided on the upper end of the inner liner (2), and a heat-insulating material (7) is provided on the inner side of the upper cover (6). The temperature material (7) is provided with an electric heating pipe (8) on the inner side of the inner tank (2); the sealed chamber (3) is connected to the pressure regulating chamber (10) via a ventilation pipeline (9); the pressure regulating chamber (10) is provided with an automatic pressure relief control valve (11), an automatic pressure increase control valve (12) and a pressure gauge (13); the sealed chamber (3) is connected to the impregnation liquid pool (15) via a liquid inlet pipeline (14); the liquid inlet pipeline (14) is provided with a high-pressure pump (16) and an electric valve (17); Temperature sensors are provided between the outer side of the outer liner (1) and the heat-insulating material (7), and on the inner side of the inner liner (2); The outer shell (5) and the upper cover (6) are both provided with a temperature control instrument (18), and the temperature control instrument (18) is electrically connected to temperature sensors provided between the outer side of the outer liner (1) and the heat insulating material (7) and the inner side of the inner liner (2), respectively.

2. The carbon fiber preform high pressure impregnation and pressurized carbonization equipment according to claim 1, characterized in that: The upper ends of the outer liner (1) and the inner liner (2) are both provided with an annular outer edge, and the outer edges of the outer liner (1) and the inner liner (2) are provided with corresponding threaded holes, and the outer liner (1) and the inner liner (2) are connected together by connecting bolts (19).

3. The carbon fiber preform high pressure impregnation and pressurized carbonization equipment according to claim 1, characterized in that: A sealing ring (20) is provided between the outer edge of the outer liner (1) and the outer edge of the inner liner (2).

4. The carbon fiber preform high pressure impregnation and pressurized carbonization equipment according to claim 1, characterized in that: The top of the sealed cavity (3) is provided with a vent (2-1) connected to the vent pipeline (9), and the bottom of the sealed cavity (3) is provided with an impregnation liquid inlet (1-1) connected to the liquid inlet pipeline (14).

5. The carbon fiber preform high pressure impregnation and pressurized carbonization equipment according to claim 1, characterized in that: The gap at any point of the sealed cavity (3) is 2-3 mm larger than the thickness of the carbon fiber preform (4) therein.

6. A process for high-pressure impregnation and pressurized carbonization of a carbon fiber preform using the apparatus according to any one of claims 1 to 5, characterized in that: It includes the following steps: (1) Preform weaving: Use T700 raw silk to produce carbon cloth and mesh tire, calculate the amount according to size density, cross-layer weaving, 30 needles / cm 2 , obtaining a carbon fiber preform; (2) Preparation of impregnation solution: add 0.5-1.0 wt% of one-dimensional or two-dimensional nanocarbon material to coal tar pitch, heat and mix evenly, and set aside; (3) High-pressure impregnation: The impregnation solution prepared in step (2) is added according to the density of the carbon fiber preform from 0.45 g / cm 3 Increase to 1.5g / cm 3 Add the calculated amount of , immerse the carbon fiber preform, and keep it at 140~160℃ for 1~2h under 5~8MPa; (4) Pressurized carbonization: After the treatment in step (3) is completed, the pressure is reduced to 2-4 MPa, and the temperature is programmed to 850±10°C for carbonization for 3-4 h. The programmed temperature curve is as follows: heating to 230°C for 3 h; 230°C for 2 h; 230 to 650°C for 18 h; 650 to 850°C for 9 h; 850°C for 4 h; (5) Product removal: Cool down to room temperature, reduce pressure to atmospheric pressure, take out the carbon fiber preform, and you are done.

7. The high-pressure impregnation and pressurized carbonization process for a carbon fiber preform according to claim 6, characterized in that: The softening point of the coal tar pitch in step (2) is 90-100° C., and the coking value is greater than 45%.

8. The high-pressure impregnation and pressurized carbonization process for a carbon fiber preform according to claim 6, characterized in that: In the step (2), the heating temperature is 150-180° C., and ultrasonic mixing is used.

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