Hot-press curing method and hot-press curing system for carbon fiber rigid felt

Abstract

This invention discloses a hot-press curing method and system for carbon fiber rigid felt, relating to the field of carbon fiber rigid felt preparation technology. Its main objective is to avoid the threat to safe production posed by mixed gases containing VOCs during the hot-press curing process of carbon fiber rigid felt, and to reduce the amount of exhaust gas emitted. The main technical solution of this invention is: a hot-press curing method for carbon fiber rigid felt, comprising the following steps: Step S1, sealing the hot press and purging it with inert gas; Step S2, performing the hot-press curing process under inert gas protection, recovering alcohol; Step S3, performing the hot-press curing process in a dust-free environment and explosion-proof atmosphere, recovering waste liquid; Step S4, releasing the seal of the hot press to obtain the carbon fiber hot-press cured felt.

Description

Technical Field

[0001] This invention relates to the field of carbon fiber rigid felt preparation technology, and in particular to a hot-press curing method and system for carbon fiber rigid felt. Background Technology

[0002] In the existing hot-press curing process for rigid carbon fiber felt, a mixture of air and VOCs is generated in the hot press preform. To ensure safe production, the amount of air supplied to the hot press and the amount of exhaust gas discharged from the hot press are increased to reduce the VOCs content in the gas. However, this process has the following disadvantages:

[0003] 1. Mixed gases containing VOCs constantly threaten safe production;

[0004] 2. Adding ambient air will introduce dust, which will affect product quality;

[0005] 3. High energy consumption;

[0006] 4. Large volume of exhaust gas is discharged, and treatment is difficult. Summary of the Invention

[0007] In view of this, embodiments of the present invention provide a hot-press curing method and system for rigid carbon fiber felt, the main purpose of which is to reduce the amount of exhaust gas discharged during the hot-press curing production process of rigid carbon fiber felt.

[0008] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0009] On one hand, one embodiment of the present invention provides a hot-press curing method for carbon fiber rigid felt, the method comprising the following steps:

[0010] Step S1: Seal the hot press and purge it with inert gas.

[0011] The carbon fiber rigid felt preform is placed in a hot press and the hot press is sealed. The cooler is started and the cooling temperature is maintained at -35 to -5℃. Inert gas is introduced into the hot press to replace the air in the hot press. During the replacement process, a first mixed gas is formed in the hot press. The first mixed gas is cooled by the cooler, and the alcohol gas in the first mixed gas condenses into liquid alcohol and is recovered into the alcohol recovery tank. The uncondensed components in the first mixed gas are discharged to the exhaust gas discharge pipe. When the oxygen content in the hot press is ≤10%, preferably ≤3%, the inert gas replacement is completed.

[0012] Step S2: Perform hot-press curing under inert gas protection to recover alcohol.

[0013] The hot press is heated at a rate of 0.1-3℃ per minute, and inert gas is continuously added to the hot press. Under the protection of the inert gas, the carbon fiber rigid felt preform inside the hot press is hot-pressed and cured. The alcohol gas generated during the hot-pressing and curing process forms a second mixed gas under the protection of the inert gas. The cooling temperature of the cooler is maintained at -35-10℃. The second mixed gas is cooled by the cooler, and the alcohol gas in the second mixed gas condenses into liquid alcohol, which is recovered into the alcohol recovery tank. The uncondensed components in the second mixed gas are discharged into the exhaust gas pipeline. When the temperature inside the hot press reaches 68-105℃ and the alcohol concentration of the second mixed gas inside the hot press is less than the predetermined alcohol concentration for a period of 10-60 minutes, the alcohol recovery operation ends.

[0014] Step S3: Perform hot-press curing process in a dust-free environment and explosion-proof atmosphere, and recycle waste liquid.

[0015] The hot press is heated at a rate of 0.2-2℃ per minute. One or more of compressed air, purified air, nitrogen, and argon are introduced into the hot press to adjust the oxygen and VOC concentrations in the gas inside the hot press, forming a third mixed gas. This keeps the VOC concentration in the hot press below 50% of the lower explosive limit. The carbon fiber rigid felt preform inside the hot press is then hot-pressed and cured. The cooler temperature is maintained at -35-0℃, preferably -30-10℃. The third mixed gas is cooled by the cooler, and the VOCs in the third mixed gas condense into waste liquid, which is recovered into the waste liquid tank. The uncondensed components in the third mixed gas are discharged to the exhaust gas pipe. The hot press temperature is raised to the final hot-pressing curing temperature of 140-285℃, preferably 180-260℃, and held at this temperature for 5-180 minutes, preferably 45-120 minutes. The cooler cold source is then turned off, the heat transfer oil heating is stopped, and the hot press enters the natural cooling stage.

[0016] Step S4: Release the seal of the hot press to obtain carbon fiber hot-pressed curing felt.

[0017] During the natural cooling stage, when the temperature inside the hot press is ≤120℃, preferably ≤80℃, and the oxygen concentration is ≥19.5% (v / v), the hot press seal is released to obtain hot-pressed and cured carbon fiber rigid felt.

[0018] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0019] Optionally, the operating pressure of the hot press is 1-50 Pa, preferably 2-10 Pa.

[0020] Optionally, in step S1, the carbon fiber rigid felt preform is a carbon fiber preform containing a carbon precursor.

[0021] Optionally, in step S2, the hot press is heated at a rate of 0.2-1°C per minute.

[0022] Optionally, in step S2, the required duration is 30-50 minutes.

[0023] Optionally, in step S2, the cooling temperature of the cooler is maintained at -30 to -5°C.

[0024] Optionally, in step S2, the oxygen content inside the hot press is kept ≤10%, preferably ≤3%.

[0025] Optionally, in step S2, the predetermined alcohol concentration is 5% (v / v).

[0026] Optionally, in step S3, the oxygen content inside the hot press is 0.1-15% (v / v), preferably 5-8% (v / v).

[0027] On the other hand, another embodiment of the present invention also provides a hot-press curing system for carbon fiber rigid felt, the system comprising: a hot-press curing section and a recycling section;

[0028] The hot pressing curing section includes a hot press, a heater, a thermal oil pump, and a thermal oil tank. The outlet of the thermal oil pump, the heater, and the oil inlet of the hot press are connected in sequence. The thermal oil tank is connected to the inlet of the thermal oil pump and the oil outlet of the hot press. The gas phase inlet of the hot press is connected to the inert gas pipeline and the process air pipeline.

[0029] The recovery unit includes a cooler, an alcohol recovery tank, and a waste liquid tank. The inlet of the cooler is connected to the gas phase outlet of the hot press, the liquid phase outlet of the cooler is connected to the alcohol recovery tank and the waste liquid tank, and the gas phase outlet of the cooler is connected to the exhaust gas discharge pipe.

[0030] By employing the above technical solution, the present invention has at least the following advantages:

[0031] Treating alcohol gas emitted from carbon fiber rigid felt preforms in an inert gas atmosphere solves the safety hazards associated with production in an air atmosphere; alcohol recovery and reuse eliminates the waste of resources, environmental pollution, and safety hazards caused by alcohol gas emissions; hot-pressing curing in a dust-free, explosion-proof environment ensures the oxygen requirements for hot-pressing curing, solves the problem of product quality degradation caused by dust introduced from the ambient air, and also eliminates existing safety hazards; cooling and recovering some of the resin hot-pressing curing reaction products reduces the pressure on exhaust gas treatment and lowers subsequent energy consumption.

[0032] The current technology sets the alcohol concentration alarm value at 0.0828% (v / v), which is 25% of the lower explosive limit of alcohol in air (3.3%). This corresponds to 17 grams of alcohol per standard cubic meter of air (17 g / m³). Reaching this alarm value requires replenishing ambient air. Assuming 1 kg of alcohol evaporates, 58.82 standard cubic meters of air are needed to dilute it.

[0033] This application uses an inert gas with an oxygen content of less than 3% for protection. The volatilized alcohol gas is condensed together with the protective gas, so there is no risk of alcohol explosion. The alcohol concentration in the condensed gas can be as high as 200g / m3 or more, which can be carried by 5 standard cubic meters of inert gas. Therefore, the amount of exhaust gas discharged by this application is reduced by more than 90%.

[0034] In existing technologies, the VOCs generated by alcohol evaporation and resin pyrolysis in hot presses typically amount to 700-1100 kg, averaging 900 kg, requiring approximately 50,000 standard cubic meters of fresh air. The biggest problem is the presence of particles larger than 10 gm in the air at the production site, as their quantity directly affects product quality. Generally, the ash content of rigid carbon fiber felt should be less than 500 ppm, better quality less than 200 ppm, and higher quality less than 100 ppm. In this application, the gas used in the processing is inert gas, compressed air, or purified air, thus eliminating the introduction of dust and ensuring that the ash content of the rigid carbon fiber felt meets the requirements. Attached Figure Description

[0035] Figure 1 A flowchart of a hot-press curing method for carbon fiber rigid felt provided in an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of a hot-press curing system for carbon fiber rigid felt provided in an embodiment of the present invention.

[0037] The reference numerals in the accompanying drawings include: 1. Hot press; 2. Heater; 3. Thermal oil pump; 4. Thermal oil tank; 5. Inert gas pipeline; 6. Process air pipeline; 7. Cooler; 8. Alcohol recovery tank; 9. Waste liquid tank; 10. Exhaust gas discharge pipeline. Detailed Implementation

[0038] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Example 1

[0040] like Figure 1 As shown, an embodiment of the present invention provides a hot-press curing method for carbon fiber rigid felt, which includes the following steps:

[0041] Step S1: Seal the hot press and purge it with inert gas.

[0042] The carbon fiber rigid felt preform is placed in a hot press and the hot press is sealed. The cooler is started and the cooling temperature is maintained at -35 to -5℃. Nitrogen gas is introduced into the hot press to replace the air. During the replacement process, a first mixed gas is formed in the hot press, and the pressure of the first mixed gas is 1-5 Pa. The first mixed gas is cooled by the cooler, and the alcohol gas in the first mixed gas condenses into liquid alcohol and is recovered into the alcohol recovery tank. The uncondensed components in the first mixed gas are discharged to the exhaust gas pipe. When the oxygen content in the hot press is ≤3%, the inert gas replacement is completed.

[0043] Step S2: Perform hot-press curing under inert gas protection to recover alcohol.

[0044] The hot press is heated at a rate of 0.2-1℃ per minute, and nitrogen is continuously added to the hot press. Under nitrogen protection, the carbon fiber rigid felt preform inside the hot press is hot-pressed and cured. During the hot-pressing and curing process, alcohol gas and inert gas are generated to form a second mixed gas. The gas phase pressure inside the hot press is maintained at 1-5 Pa, and the cooling temperature of the cooler is maintained at -30 to -5℃. The second mixed gas is cooled by the cooler, and the alcohol gas in the second mixed gas condenses into liquid alcohol, which is recovered into the alcohol recovery tank. The uncondensed components in the second mixed gas are discharged into the exhaust gas pipeline. When the temperature inside the hot press is ≥80℃ and the alcohol concentration of the second mixed gas inside the hot press is less than 5% (v / v) for a duration of 30-60 minutes, the alcohol recovery operation ends.

[0045] Step S3: Perform hot-press curing process in a dust-free environment and explosion-proof atmosphere, and recycle waste liquid:

[0046] The hot press is heated at a rate of 0.2-2℃ per minute. One or more of compressed air, purified air, nitrogen, and argon are introduced into the hot press, and the gas phase pressure inside the hot press is maintained at 1-5 Pa to adjust the oxygen and VOC concentrations in the gas, forming a third mixed gas. The oxygen content of the gas inside the hot press is 5-10% (v / v), and the VOC concentration is below 50% of the lower explosive limit. The carbon fiber rigid felt preform inside the hot press is hot-pressed and cured. The cooling temperature of the cooler is maintained at -30 to -10℃. The third mixed gas is cooled by the cooler, and the VOCs in the third mixed gas condense into waste liquid and are recycled to the waste liquid tank. The uncondensed components in the third mixed gas are discharged to the exhaust gas pipe. The hot press temperature is raised to the final hot-pressing curing temperature of 180℃ and held at that temperature for 45-120 minutes. The cooler cold source is turned off, the heat transfer oil heating is stopped, and the hot press enters the natural cooling stage.

[0047] Step S4: Remove the seal of the hot press to obtain carbon fiber hot-pressed curing felt:

[0048] During the natural cooling stage, when the temperature inside the hot press is ≤80℃, the oxygen content of the gas introduced into the hot press is increased to ≥21% (v / v). When the oxygen concentration of the gas inside the hot press is ≥19.5% (v / v), the hot press seal is released to obtain hot-pressed and cured carbon fiber rigid felt. Example 2

[0049] like Figure 1 As shown, an embodiment of the present invention provides a hot-press curing method for carbon fiber rigid felt, which includes the following steps:

[0050] Step S1: Seal the hot press and purge it with inert gas.

[0051] The carbon fiber rigid felt preform is placed in a hot press and the hot press is sealed. The cooler is started and the cooling temperature is maintained at -30 to -15℃. Nitrogen gas is introduced into the hot press to replace the air. During the replacement process, a first mixed gas is formed in the hot press, and the pressure of the first mixed gas is 5-50 Pa. The first mixed gas is cooled by the cooler, and the alcohol gas in the first mixed gas condenses into liquid alcohol and is recovered into the alcohol recovery tank. The uncondensed components in the first mixed gas are discharged to the exhaust gas pipe. When the oxygen content in the hot press is ≤10%, the inert gas replacement is completed.

[0052] Step S2: Perform hot-press curing under inert gas protection to recover alcohol.

[0053] The hot press is heated at a rate of 0.1-0.6℃ per minute, and nitrogen is continuously added to the hot press. Under nitrogen protection, the carbon fiber rigid felt preform inside the hot press is hot-pressed and cured. During the hot-pressing and curing process, alcohol gas and inert gas are generated to form a second mixed gas. The gas phase pressure inside the hot press is maintained at 5-50 Pa, and the cooling temperature of the cooler is maintained at -35 to -10℃. The second mixed gas is cooled by the cooler, and the alcohol gas in the second mixed gas condenses into liquid alcohol, which is recovered into the alcohol recovery tank. The uncondensed components in the second mixed gas are discharged into the exhaust gas pipeline. When the temperature inside the hot press reaches 105℃ and the alcohol concentration of the second mixed gas inside the hot press is less than 5% (v / v) for a duration of 10-25 minutes, the alcohol recovery operation ends.

[0054] Step S3: Perform hot-press curing process in a dust-free environment and explosion-proof atmosphere, and recycle waste liquid:

[0055] The hot press is heated at a rate of 0.2-1℃ per minute. One or more of compressed air, purified air, nitrogen, and argon are introduced into the hot press, and the gas phase pressure inside the hot press is maintained at 5-50 Pa to adjust the oxygen and VOC concentrations in the gas, forming a third mixed gas. The oxygen content of the gas inside the hot press is 0.1-5% (v / v), and the VOC concentration is below 50% of the lower explosive limit. The carbon fiber rigid felt preform inside the hot press is hot-pressed and cured. The cooling temperature of the cooler is maintained at -35 to -10℃. The third mixed gas is cooled by the cooler, and the VOCs in the third mixed gas condense into waste liquid and are recycled to the waste liquid tank. The uncondensed components in the third mixed gas are discharged to the exhaust gas pipe. The temperature of the hot press is raised to the final hot-pressing curing temperature of 200℃ and held for 5-30 minutes. The cooler cold source is turned off, the heat transfer oil heating is stopped, and the hot press enters the natural cooling stage.

[0056] Step S4: Remove the seal of the hot press to obtain carbon fiber hot-pressed curing felt:

[0057] During the natural cooling stage, when the temperature inside the hot press is ≤120℃, the oxygen content of the gas introduced into the hot press is increased to ≥21% (v / v). When the oxygen concentration of the gas inside the hot press is ≥19.5% (v / v), the hot press seal is released to obtain hot-pressed and cured carbon fiber rigid felt. Example 3

[0058] like Figure 1 As shown, an embodiment of the present invention provides a hot-press curing method for carbon fiber rigid felt, which includes the following steps:

[0059] Step S1: Seal the hot press and purge it with inert gas.

[0060] The carbon fiber rigid felt preform is placed in a hot press and the hot press is sealed. The cooler is started and the cooling temperature is maintained at -20 to -5℃. Nitrogen gas is introduced into the hot press to replace the air. During the replacement process, a first mixed gas is formed in the hot press, and the pressure of the first mixed gas is 3-20 Pa. The first mixed gas is cooled by the cooler, and the alcohol gas in the first mixed gas condenses into liquid alcohol and is recovered into the alcohol recovery tank. The uncondensed components in the first mixed gas are discharged to the exhaust gas pipe. When the oxygen content in the hot press is ≤3%, the inert gas replacement is completed.

[0061] Step S2: Perform hot-press curing under inert gas protection to recover alcohol.

[0062] The hot press is heated at a rate of 0.3-3℃ per minute, and nitrogen is continuously added to the hot press. Under nitrogen protection, the carbon fiber rigid felt preform inside the hot press is hot-pressed and cured. During the hot-pressing and curing process, alcohol gas and inert gas are generated to form a second mixed gas. The gas phase pressure inside the hot press is maintained at 3-20 Pa, and the cooling temperature of the cooler is maintained at -25-10℃. The second mixed gas is cooled by the cooler, and the alcohol gas in the second mixed gas condenses into liquid alcohol, which is recovered into the alcohol recovery tank. The uncondensed components in the second mixed gas are discharged into the exhaust gas pipeline. When the temperature inside the hot press is ≥68℃ and the alcohol concentration of the second mixed gas inside the hot press is less than 5% (v / v) for a duration of 45-60 minutes, the alcohol recovery operation ends.

[0063] Step S3: Perform hot-press curing process in a dust-free environment and explosion-proof atmosphere, and recycle waste liquid:

[0064] The hot press is heated at a rate of 0.2-1℃ per minute. One or more of compressed air, purified air, nitrogen, and argon are introduced into the hot press, and the gas phase pressure inside the hot press is maintained at 3-20 Pa to adjust the oxygen and VOC concentrations in the gas, forming a third mixed gas. The oxygen content of the gas inside the hot press is 5-15% (v / v), and the VOC concentration is below 50% of the lower explosive limit. The carbon fiber rigid felt preform inside the hot press is hot-pressed and cured. The cooling temperature of the cooler is maintained at -25-0℃. The third mixed gas is cooled by the cooler, and the VOCs in the third mixed gas condense into waste liquid and are recycled to the waste liquid tank. The uncondensed components in the third mixed gas are discharged to the exhaust gas pipe. The temperature of the hot press is raised to the final hot-pressing curing temperature of 150℃ and held at that temperature for 60-180 minutes. The cooler cold source is turned off, the heat transfer oil heating is stopped, and the hot press enters the natural cooling stage.

[0065] Step S4: Remove the seal of the hot press to obtain carbon fiber hot-pressed curing felt:

[0066] During the natural cooling stage, when the temperature inside the hot press is ≤85℃, the oxygen content of the gas introduced into the hot press is increased to ≥21% (v / v). When the oxygen concentration of the gas inside the hot press is ≥19.5% (v / v), the hot press seal is released to obtain hot-pressed and cured carbon fiber rigid felt. Example 4

[0067] like Figure 1 As shown, an embodiment of the present invention provides a hot-press curing method for carbon fiber rigid felt, which includes the following steps:

[0068] Step S1: Seal the hot press and purge it with inert gas.

[0069] The carbon fiber rigid felt preform is placed in a hot press and the hot press is sealed. The cooler is started and the cooling temperature is maintained at -25 to -15℃. Nitrogen gas is introduced into the hot press to replace the air. During the replacement process, a first mixed gas is formed in the hot press, and the pressure of the first mixed gas is 5-15 Pa. The first mixed gas is cooled by the cooler, and the alcohol gas in the first mixed gas condenses into liquid alcohol and is recovered into the alcohol recovery tank. The uncondensed components in the first mixed gas are discharged to the exhaust gas pipe. When the oxygen content in the hot press is ≤2%, the inert gas replacement is completed.

[0070] Step S2: Perform hot-press curing under inert gas protection to recover alcohol.

[0071] The hot press is heated at a rate of 0.1-3℃ per minute, and nitrogen is continuously added to the hot press. Under nitrogen protection, the carbon fiber rigid felt preform inside the hot press is hot-pressed and cured. During the hot-pressing and curing process, alcohol gas and inert gas are generated to form a second mixed gas. The gas phase pressure inside the hot press is maintained at 5-15 Pa, and the cooling temperature of the cooler is maintained at -25 to -10℃. The second mixed gas is cooled by the cooler, and the alcohol gas in the second mixed gas condenses into liquid alcohol, which is recovered into the alcohol recovery tank. The uncondensed components in the second mixed gas are discharged into the exhaust gas pipeline. When the temperature inside the hot press is ≥86℃ and the alcohol concentration of the second mixed gas inside the hot press is less than 5% (v / v) for a duration of 45-60 minutes, the alcohol recovery operation ends.

[0072] Step S3: Perform hot-press curing process in a dust-free environment and explosion-proof atmosphere, and recycle waste liquid:

[0073] The hot press is heated at a rate of 0.2-1.5℃ per minute. One or more of compressed air, purified air, nitrogen, and argon are introduced into the hot press, and the gas phase pressure inside the hot press is maintained at 5-15 Pa to adjust the oxygen and VOC concentrations in the gas, forming a third mixed gas. The oxygen content of the gas inside the hot press is 0.5-5% (v / v), and the VOC concentration is below 50% of the lower explosive limit. The carbon fiber rigid felt preform inside the hot press is hot-pressed and cured. The cooling temperature of the cooler is maintained at -20-0℃. The third mixed gas is cooled by the cooler, and the VOCs in the third mixed gas condense into waste liquid and are recycled to the waste liquid tank. The uncondensed components in the third mixed gas are discharged to the exhaust gas pipe. The hot press temperature is raised to the final hot-pressing curing temperature of 240℃ and held at that temperature for 30-120 minutes. The cooler cold source is turned off, the heat transfer oil heating is stopped, and the hot press enters the natural cooling stage.

[0074] Step S4: Remove the seal of the hot press to obtain carbon fiber hot-pressed curing felt:

[0075] During the natural cooling stage, when the temperature inside the hot press is ≤78℃, the oxygen content of the gas introduced into the hot press is increased to 21% (v / v) or higher. When the oxygen concentration of the gas inside the hot press is ≥19.5% (v / v), the hot press seal is released to obtain hot-pressed and cured carbon fiber rigid felt.

[0076] like Figure 2 As shown, another embodiment of the present invention also provides a hot-press curing system for carbon fiber rigid felt, the system comprising: a hot-press curing section and a recycling section;

[0077] The hot pressing curing section includes a hot press 1, a heater 2, a thermal oil pump 3, and a thermal oil tank 4. The outlet of the thermal oil pump 3, the heater 2, and the oil inlet of the hot press 1 are connected in sequence. The thermal oil tank 4 is connected to the inlet of the thermal oil pump 3 and the oil outlet of the hot press 1. The gas phase inlet of the hot press 1 is connected to the inert gas pipeline 5 and the process air pipeline 6.

[0078] The recovery unit includes a cooler 7, an alcohol recovery tank 8, and a waste liquid tank 9. The inlet of the cooler 7 is connected to the gas phase outlet of the hot press 1, the liquid phase outlet of the cooler 7 is connected to the alcohol recovery tank 8 and the waste liquid tank 9, and the gas phase outlet of the cooler 7 is connected to the exhaust gas discharge pipe 10.

[0079] Specifically, the hot press 1 is a sealed hot press 1, which has a sealing effect that can prevent VOCs from overflowing.

[0080] Specifically, the heat transfer oil tank 4 serves to store the heat transfer oil.

[0081] Specifically, the process air consists of one or two of compressed air, purified air, nitrogen, and argon. Nitrogen, argon, or process air are selectively introduced into the compressor to enable the hot press 1 to operate in a dust-free environment.

[0082] Specifically, control valves are installed on the connecting pipes between the hot press 1, cooler 7, heater 2, heat transfer oil pump 3, heat transfer oil tank 4, alcohol recovery tank 8, and waste liquid tank 9, as well as on the inert gas pipe 5, process air pipe 6, and exhaust gas discharge pipe 10, to control the on / off state or regulate the flow rate.

[0083] Specifically, a volatile organic compound gas analyzer is configured to monitor the gas phase of the hot press 1 and the gas phase of the cooler 7 in real time, and to monitor organic compounds with boiling points below or equal to 250°C.

[0084] Specifically, an online oxygen and inert gas detector is configured to monitor the gas phase of the hot press 1 and the process air duct 6 online.

[0085] Specifically, the alcohol recovered in step S2 and the waste liquid from the resin thermosetting reaction product recovered in step S3 are treated together as waste liquid. The alcohol recovery tank 8 can be omitted. The liquid outlet of the cooler 7 is only connected to the material inlet of the waste liquid tank 9. The alcohol condensed in step S2 is returned to the waste liquid tank 9.

[0086] Specifically, cooler 7 uses a vertical tube heat exchanger.

[0087] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A hot-press curing method for carbon fiber rigid felt, characterized in that, Includes the following steps: Step S1: Seal the hot press and purge it with inert gas. The carbon fiber rigid felt preform is placed in a hot press and the hot press is sealed. The cooler is started and the cooling temperature is maintained at -35 to -5℃. Inert gas is introduced into the hot press to replace the air in the hot press. During the replacement process, a first mixed gas is formed in the hot press. The first mixed gas is cooled by the cooler, and the alcohol gas in the first mixed gas condenses into liquid alcohol and is recovered into the alcohol recovery tank. The uncondensed components in the first mixed gas are discharged to the exhaust gas pipe. When the oxygen content in the hot press is ≤10%, the inert gas replacement is completed. Step S2: Perform hot-press curing under inert gas protection to recover alcohol. The hot press is heated at a rate of 0.1-3℃ per minute, and inert gas is continuously added to the hot press. Under the protection of the inert gas, the carbon fiber rigid felt preform inside the hot press is hot-pressed and cured. The alcohol gas generated during the hot-pressing and curing process forms a second mixed gas under the protection of the inert gas. The cooling temperature of the cooler is maintained at -35-10℃. The second mixed gas is cooled by the cooler, and the alcohol gas in the second mixed gas condenses into liquid alcohol, which is recovered into the alcohol recovery tank. The uncondensed components in the second mixed gas are discharged into the exhaust gas pipeline. When the temperature inside the hot press reaches 68-105℃ and the alcohol concentration of the second mixed gas inside the hot press is less than the predetermined alcohol concentration for a period of 10-60 minutes, the alcohol recovery operation ends. Step S3: Perform hot-press curing process in a dust-free environment and explosion-proof atmosphere, and recycle waste liquid: The hot press is heated at a rate of 0.2-2℃ per minute. One or more of compressed air, purified air, nitrogen, and argon are introduced into the hot press to adjust the oxygen and VOC concentrations in the gas, forming a third mixed gas. This keeps the VOC concentration in the hot press below 50% of the lower explosive limit. The carbon fiber rigid felt preform inside the hot press is then hot-pressed and cured. The cooler temperature is maintained at -35 to 0℃. The third mixed gas is cooled by the cooler, and the VOCs in the third mixed gas condense into waste liquid, which is then recovered into the waste liquid tank. The uncondensed components in the third mixed gas are discharged to the exhaust gas pipe. The hot press temperature is raised to the final hot-pressing curing temperature of 140-285℃ and held for 5-180 minutes. The cooler cold source is then turned off, the heat transfer oil heating is stopped, and the hot press enters the natural cooling stage. Step S4: Remove the seal of the hot press to obtain carbon fiber hot-pressed curing felt: During the natural cooling stage, when the temperature inside the hot press is ≤120℃ and the oxygen concentration is ≥19.5% (v / v), the hot press seal is released to obtain hot-pressed and cured carbon fiber rigid felt.

2. The hot-press curing method for carbon fiber rigid felt according to claim 1, characterized in that, The operating pressure of the hot press is 1-50 Pa.

3. The hot-press curing method for carbon fiber rigid felt according to claim 1, characterized in that, In step S1, the carbon fiber rigid felt preform is a carbon fiber preform containing a carbon precursor.

4. The hot-press curing method for carbon fiber rigid felt according to claim 1, characterized in that, In step S2, the hot press is heated at a rate of 0.2-1°C per minute.

5. The hot-press curing method for carbon fiber rigid felt according to claim 1, characterized in that, In step S2, the required duration is 30-50 minutes.

6. The hot-press curing method for carbon fiber rigid felt according to claim 1, characterized in that, In step S2, the cooling temperature of the cooler is maintained at -30 to -5°C.

7. The hot-press curing method for carbon fiber rigid felt according to claim 1, characterized in that, In step S2, the oxygen content inside the hot press is kept ≤10%.

8. The hot-press curing method for carbon fiber rigid felt according to claim 1, characterized in that, In step S2, the predetermined alcohol concentration is 5% (v / v).

9. The hot-press curing method for carbon fiber rigid felt according to claim 1, characterized in that, In step S3, the oxygen content inside the hot press is 0.1-15% (v / v).

10. A hot-press curing system for carbon fiber rigid felt, characterized in that, The system for implementing the hot-press curing method for carbon fiber rigid felt according to claim 1 comprises: The hot-press curing section includes a hot press, a heater, a thermal oil pump, and a thermal oil tank. The outlet of the thermal oil pump, the heater, and the oil inlet of the hot press are connected in sequence. The thermal oil tank is connected to the inlet of the thermal oil pump and the oil outlet of the hot press. The gas phase inlet of the hot press is connected to an inert gas pipeline and a process air pipeline. The recovery unit includes a cooler, an alcohol recovery tank, and a waste liquid tank. The inlet of the cooler is connected to the gas phase outlet of the hot press, the liquid phase outlet of the cooler is connected to the alcohol recovery tank and the waste liquid tank, and the gas phase outlet of the cooler is connected to the exhaust gas discharge pipe.

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