Nitrogen circulation furan resin glass carbon cracking furnace device

Abstract

This invention relates to a nitrogen-circulating furan resin glass carbon pyrolysis furnace apparatus. The apparatus includes a pyrolysis furnace body (5), a high-temperature fan (1), a silicon carbide rod heating device (3), an airflow distributor (4), an air duct (2), and a filter (6). An airflow distributor (4) is installed at both the front and rear ends of the pyrolysis furnace body (5). The rear end of the airflow distributor (4) at the rear end of the pyrolysis furnace body (5) is connected to the filter (6), and the rear end of the filter (6) is connected to the high-temperature fan (1). The rear end of the high-temperature fan (1) is connected to the silicon carbide rod heating device (3), and the rear end of the silicon carbide rod heating device (3) is connected to the airflow distributor (4) at the front end of the pyrolysis furnace body (5). This invention overcomes the shortcomings of the prior art and provides a glass carbon production apparatus with high glass carbon yield, energy saving, long service life, convenient operation and maintenance, and reduced equipment investment.

Description

Technical Field

[0001] This invention relates to a pyrolysis furnace device, specifically a nitrogen-circulating furan resin to glassy carbon pyrolysis furnace device, belonging to the technical field of special heating furnaces in chemical equipment. Background Technology

[0002] Currently, the electrolytic production of hexamethylenediamine from adiponitrile is one of the commonly used and typical processes in the fine chemical industry. The electrolytic cell requires the conductive film on the electrode plates to be made of glassy carbon material, which is black and transparent in appearance, has a smooth and wear-resistant surface, a resistance of less than 1 ohm at room temperature, and possesses excellent qualities such as high-temperature resistance and resistance to acid and alkali corrosion. It is widely used in electrolysis equipment in the fine chemical industry.

[0003] Glassy carbon is a non-crystalline carbon structural material made by carbonizing furan resin by heating it to 850℃ in an oxygen-free environment. There is no record of mass production of this type of product in China, and most of the required products are imported. It is a high-tech product.

[0004] During the pyrolysis of furan resin glassy carbon at 850°C, numerous conductive, flocculent oligomers are produced. In a vacuum muffle furnace, these flocculents cannot be removed by filtration, and they gradually adhere to the periphery of the silicon carbide rod. Excessive accumulation leads to adhesion, causing a short circuit between the positive and negative electrodes of the silicon carbide rod, potentially resulting in a fire and electrical safety hazard. This is a fatal flaw that the vacuum muffle furnace cannot overcome. During the invention and trial production, we used surface-insulated heating wire rods in a vacuum muffle furnace. While this solved the adhesion and short-circuit problem, the surface temperature of the heating wire rod was much lower than that of the silicon carbide rod, and the volumetric space heating did not reach 850°C, failing to meet the process requirements. Neither of the two experiments conducted in the vacuum muffle furnace yielded a qualified glassy carbon product. Therefore, a new solution is urgently needed to address these technical problems. Summary of the Invention

[0005] This invention addresses the problems existing in the prior art by providing a nitrogen-circulating furan resin glass carbon pyrolysis furnace device. This technical solution provides a glass carbon pyrolysis device with high glass carbon yield, energy saving, long service life, convenient operation and maintenance, and reduced equipment investment. Addressing the problems encountered in the vacuum muffle furnace during the glass carbon refining process, this invention develops and designs a high-temperature pyrolysis furnace device that meets the requirements of glass carbon products for glass carbon manufacturing.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: a nitrogen-circulating furan resin glass carbon pyrolysis furnace device, characterized in that the device includes a pyrolysis furnace body, a high-temperature fan, a silicon carbide rod heating device, an airflow distributor, an air duct, and a filter, wherein an airflow distributor is respectively provided at the front and rear ends of the pyrolysis furnace body, the rear end of the airflow distributor at the rear end of the pyrolysis furnace body is connected to the filter, the rear end of the filter is connected to the high-temperature fan, the rear end of the high-temperature fan is connected to the silicon carbide rod heating device, the rear end of the silicon carbide rod heating device is connected to the airflow distributor at the front end of the pyrolysis furnace body, and the air duct connects all the above devices into a whole.

[0007] As an improvement of this invention, the duct includes several straight sections and three elbows. The straight sections and elbows are made of S310 high-temperature alloy and are welded together, respectively connected to the high-temperature fan, heating device, pyrolysis device, and filtration device, forming a closed ring structure within a relatively small area. This allows the high-temperature hot airflow to flow within the duct at a certain speed and direction, enabling accelerated and uniform heat transfer. Minimizing the number of elbows and straight sections helps reduce the resistance to the high-temperature airflow and minimize heat loss.

[0008] As an improvement of the present invention, the pyrolysis furnace body is provided with a circular cylinder, with a crown-shaped end cap of the same specification at each end of the cylinder. A flange is welded between each crown-shaped end cap and the cylinder, and the two flanges are connected by fastening bolts, fastening nuts, and sealing gaskets. The closed cavity structure of the circular cylinder and crown-shaped end caps ensures safe operation under negative pressure conditions. Its local stress and membrane stress are much lower than those of a rectangular cylinder structure, and it is easier to manufacture, significantly improving operational safety and saving manufacturing time, materials, and costs. One end cap is connected to the cylinder by a pair of flanges for sealing, serving as a door for easy opening and closing, used for loading raw materials and recovering products. Considering that the operating temperature of the cylinder reaches 850℃, the cylinder support legs cannot be in direct contact with the ground, as this would transfer a lot of heat.

[0009] As an improvement of this invention, a cooling system is installed inside the two flanges to prevent high temperatures from damaging the flange seals. Two parallel guide rails are installed inside the cylinder to support the glass carbon mold. An airflow distribution plate is installed on the outer side of each guide rail. Four connecting flanges are located at the top of the cylinder, and four heat-insulating legs are located at the bottom. Nine small holes are opened on each side of the cylinder opposite the airflow distribution plates, connecting to the distribution pipes. The sealing flanges, after being pre-tightened with fasteners, tightly press the sealing gasket, capable of withstanding a gas pressure of 5000 Pa without leakage. When the temperature rises to 850℃, heat will be transferred to these sealing flanges. If the temperature is not reduced, the entire sealing structure will immediately fail. Using internal water cooling of the flanges solves this problem. By adjusting the water flow, the temperature of the flange sealing structure can be kept below 300℃, effectively preventing leakage. This ensures effective oxygen isolation during high-temperature operation. The glass carbon products of this invention require multiple pieces to be produced simultaneously. Each mold is placed horizontally as a single piece, and multiple pieces are placed in the pyrolysis furnace, requiring uniform temperature within the furnace, with each product reaching the same temperature. This necessitates the manufacture of a mold rack. The mold rack is designed as a wheeled trolley to store multiple layers of molds. Each layer of molds on the rack can be adjusted horizontally to ensure uniform thickness after product forming. Two parallel guide rails are installed inside the cylinder, allowing the mold rack trolley to be pushed in or pulled out. To ensure uniform temperature within the furnace, the high-temperature gas entering from the side must be evenly distributed, and the outflowing gas must also be evenly distributed to achieve a uniform temperature field within the cylinder. To ensure uniform gas distribution entering the cylinder, a multi-port inlet and outlet structure is adopted. This invention employs a thermal insulation structure using aluminum silicate insulating blocks on the legs, effectively blocking the transfer of high-temperature heat and maintaining the temperature at the contact point between the bottom of the legs and the ground at approximately 30°C. The four connecting flanges at the top of the cylinder are used for pressure controllers, nitrogen input, vacuum pumping, and high-temperature, high-pressure alarm interfaces, etc.

[0010] As an improvement of this invention, the high-temperature fan is equipped with a base, on which a bearing housing, a motor, and a volute are mounted. A coupling is provided between the motor and the drive shaft of the bearing housing. An impeller is located inside the volute and is connected to the drive shaft of the bearing housing. A cooling and sealing device is provided on the sides of the volute and the bearing housing. This device is designed with an air seal structure and a water cooling structure. A first diameter reducer is provided at the airflow outlet of the volute, and a second diameter reducer is provided at the airflow inlet of the volute. Both diameter reducers are connected to the air duct. The system of this invention operates at a maximum temperature of 850℃ and is isolated from the atmosphere. Ordinary high-temperature fans cannot meet the requirements of the system's operating conditions. The high temperature of the fan volute will inevitably be transmitted to the impeller, the drive shaft, and the first bearing in the bearing housing. If cooling measures are not taken to cool the bearing to below 100℃, the bearing will be damaged in a short time, and the system will not be able to operate normally. The fan structure of this invention uses a base for support, and the motor is connected to the drive shaft through a coupling. The drive shaft is supported by double-end bearings, with one side cantilevered and connected to the fan impeller. The impeller is surrounded by the fan casing. The bearings are mounted on the fan base along with the motor via a bearing housing. The bearing housing and motor are connected to the base via threaded connections. The bearings and drive shaft, as well as the bearings and bearing housing, are connected to each other via interference fits. The cooling and sealing device for the casing and bearing housing consists of two chambers: an air-sealed chamber and a water-cooled chamber. One side of the air-sealed chamber is welded to the fan casing, while the other side is connected to the water-cooled structure via a packing seal. The other side of the water-cooled structure is connected to the bearing housing seal ring and the bearing. The air-sealed chamber is purged with 0.08 MPa nitrogen gas to isolate the casing from the atmosphere and simultaneously cool the drive shaft. The water-sealed chamber is purged with 0.2 MPa cooling water to further cool the drive shaft. The inlet flow rate is adjusted to maintain the outlet water temperature at 100°C. The volute, impeller, and drive shaft are made of S310 high-temperature resistant alloy material. Together with the motor, coupling, drive shaft, bearing housing, cooling and sealing device, base and other components, they form a high-temperature fan device that can meet the external circulation operation under high temperature conditions of 850℃. This effectively transfers heat to the pyrolysis furnace, allowing the furan resin to absorb heat and carbonize.

[0011] As an improvement of this invention, the silicon carbide rod heating device comprises 20 U-shaped silicon carbide rods. Each rod has a positive and a negative electrode at its top. Three sealed conductive pillars are located on the outside of the casing, and two of the two diameter-reducing pillars are connected to air ducts on both sides of the casing. The heat source for the system temperature of 850℃ comes from the silicon carbide rod heating device. Ordinary metal tubular heaters, when powered by 380V AC, can only reach a surface temperature of 850℃. Through conduction and radiation with surrounding air or nitrogen, they can only reach an ambient temperature of 650℃, which cannot meet the 850℃ carbonization process requirements. The silicon carbide rod heater is made of a silicon-carbon mixture and has advantages such as high temperature resistance, low high-temperature resistance, and high heating efficiency. The U-shaped rods used in this device... The silicon carbide rod heater, with a diameter of [diameter missing], uses 380V AC power and achieves a measured surface heating temperature of 1450℃. There are 24 U-shaped [types missing]. The heating device, composed of silicon carbide rod heaters of various diameters, has a total heating power of 168KW. When connected in parallel and supplied with 380V AC power, it can achieve a maximum system temperature of 1000℃, fully meeting the process temperature requirements. Twenty-four heaters of this model are connected in parallel, arranged in six rows of four, with a U-shaped configuration facing the wind direction. The last row is unconnected and reserved as a backup in case of failure. The silicon carbide rod heater body consists of a hot end and a cold end. When energized, the hot end heats up, converting electrical energy into heat energy, while the cold end acts as a conductive bridge. This invention features a 300mm long cold end and a 500mm long hot end. The cold end is inserted into a 250mm thick rigid aluminum silicate insulation board, extending 50mm out for mounting a butterfly-type wiring clamp. One end of the U-shaped silicon carbide rod is connected to the 380V A phase via the butterfly clamp, and the other end is connected to the B phase. A 380V AC voltage is formed between phases A and B to provide power to the silicon carbide rod. The 380V external AC power supply is connected to the silicon carbide rod inside the heater via three sealed and insulated conductive pillars. The insulated part of the conductive pillars is connected to the housing of the heating device, and inorganic sealant is used to seal the contact points with the housing, ensuring a leak-proof seal between the housing and the insulated conductive pillars. The top of the heater is sealed with a square flange and insulated with a 250mm rigid aluminum silicate heat insulation board, achieving a top temperature of 60℃. The flange sealing material is made of polytetrafluoroethylene, ensuring no leakage under 5000Pa pressure. The silicon carbide rod heater housing adopts a square cylindrical structure with two conical components at both ends, welded to the air ducts at both ends. The conical components serve to rectify and stabilize the flow. The inside of the cylindrical section is insulated with 300mm thick aluminum silicate heat insulation modules on both sides. The rigid aluminum silicate plate on top, which houses the silicon carbide rod heater, presses down on the aluminum silicate modules on both sides, forming a square channel within which the silicon carbide rod heater is installed. High-temperature nitrogen gas flows into the chamber through one of the variable-diameter ends and is heated by the hot end of the silicon carbide rod heater. The silicon carbide rod surface, at a high temperature of 1450°C, exchanges heat with the nitrogen gas flow to gain energy. After multiple cycles of heat absorption, the process temperature of 850°C is finally reached.

[0012] As an improvement of this invention, the airflow distributor is located at the inlet and outlet of the pyrolysis furnace body. A connecting flange is provided at the top for installing a temperature sensor. The two ends of the gas collecting cylinder are welded and sealed. A large hole is opened on one horizontal side in the middle to connect to the air duct, and nine small holes are opened on the other side to connect to the distribution pipe. This invention adopts a one-to-nine inlet and outlet structure, effectively reducing airflow organization problems such as eddies and turbulence generated during gas entry and exit that are detrimental to uniform flow. When the nitrogen gas flows, it first enters a gas collecting cylinder for volume expansion, then is distributed into nine distribution pipes that simultaneously enter the pyrolysis furnace body, and then flows evenly through a distribution plate inside the cylinder. After passing through the glass carbon mold, the uniform fluid flows evenly through the distribution plate and then converges into another gas collecting cylinder via the nine distribution pipes, returning to the negative pressure section of the blower through the return air duct. This configuration ensures stable air pressure and uniform air velocity throughout the system, which is highly beneficial for uniform heating of the glass carbon mold. The interface flanges at the top of the inlet and outlet air ducts are used to connect electrical control components such as a temperature controller. The feedback thyristor circuit adjusts the output voltage to control the temperature of the nitrogen gas flow.

[0013] As an improvement of this invention, the filter has a circular shell with two variable-diameter cones on both sides. The smaller ends of the two variable-diameter cones are connected to the air inlet and outlet ducts, respectively. A hand hole is provided at the top of the variable-diameter cone at the air inlet end, and a connecting flange is provided on the horizontal side of each variable-diameter cone at the air inlet and outlet ends. A filter mesh is installed inside the circular shell. This invention uses a filter primarily to filter fibrous material generated during high-temperature operation of the system. Furan resin produces oligomer fibrous material during high-temperature carbonization, which has low high-temperature resistance and good conductivity. Without a filter, prolonged accumulation of fibrous material between the electrodes of the silicon carbide rod heater can cause a short circuit and lead to a major safety accident. To ensure the normal operation of the system equipment, measures need to be taken to collect the fibrous material and prevent its accumulation on the surface of the silicon carbide rod. This invention uses a stainless steel wire mesh filtration method, installing a wire mesh filter between the system ducts to filter the fibrous material generated by the system. The wire mesh filter is installed inside a circular cylinder, with a pair of rectangular flanges installed at the top, allowing the wire mesh component to be easily removed for cleaning or replacement. Two tapered sections on either side of the cylindrical body serve to rectify and stabilize the flow of the circulating gas. A handhole is provided at the top of the tapered section at the gas inlet for easy cleaning of lint from the wire mesh. A flange is installed on each of the tapered sections at both the gas inlet and outlet for mounting a differential pressure gauge. If the differential pressure reading exceeds the set value, it indicates that the wire mesh filter is clogged with lint, requiring cleaning or replacement.

[0014] A method for producing glassy carbon articles, the method comprising the following steps:

[0015] The first step is to inject furan resin slurry into a specific steel mold (such as...). Figure 2The mold is placed inside the pyrolysis furnace track frame to meet the shape requirements, and then the mold and the mold are placed horizontally together. The sealing door of the pyrolysis furnace is then closed and locked. There are four fine-tuning screws between the bottom of the mold and the track frame to adjust the mold horizontally. During adjustment, a laser level is used to correct the horizontal plane of the mold, and then a high-precision fitter's level is used for fine-tuning. The final horizontality is controlled below 0.2%. The horizontality of the track is corrected in the same way, and the final horizontality is controlled below 0.2%. This ensures that the thickness tolerance of the product is controlled within 0.1mm during the curing process of glass carbon.

[0016] The second step is to replace the air in the system with nitrogen (e.g., Figure 3 The nitrogen purity must be 99.99%. Under conditions of 0.1 Pa pressure and 5 m³ / h flow rate, perform 5-6 purging cycles. When the oxygen content of the exhaust gas is measured to be below 0.2%, gradually close the inlet valve to adjust the flow rate to 3 m³ / h; simultaneously close the exhaust valve to maintain the system nitrogen pressure at a nitrogen equilibrium state of 2000 Pa. The purging process is then complete. The lower the oxygen content of the circulating nitrogen in the system, the better the carbonization effect of the product.

[0017] The third step is to circulate cooling water (such as...) into the sealing flange of the pyrolysis furnace. Figure 4 To prevent high temperatures from damaging the pyrolysis furnace sealing flange and causing leakage, when the temperature inside the pyrolysis furnace reaches 850℃, the sealing surface temperature of the sealing flange reaches 800℃ due to heat transfer. If the sealing flange assembly is not effectively cooled, the gasket will quickly fail. To ensure effective sealing, an internal cavity is designed, and cooling water is introduced to cool the flange, gasket, and fasteners to below 300℃, achieving effective sealing.

[0018] Step 4: Start the circulating fan and run it at a low frequency of 20Hz. Start the electric heating device and slowly heat it to 200℃ according to the heating rate process requirements, and hold it at this temperature for 12 hours to allow it to slowly solidify and desolvate. The heating rate is 5℃ / hour, and the final temperature is set to 200℃. After reaching 200℃, hold it for 12 hours to complete the first stage of carbonization. The circulating fan is required to operate normally under conditions of 850℃. The following measures are taken: 1. The flow material and drive shaft are made of high-temperature resistant alloy stainless steel S31008. This material is commonly known as S310 or 2520 material. It has excellent properties such as high temperature and high strength, high temperature oxidation resistance, high temperature corrosion resistance, high temperature creep resistance, and high temperature strength preservation, as well as good weldability and processing performance. It is typically used in various high-temperature environments and in various high-temperature resistant components such as the duct system, fan casing, impeller, and drive shaft of this device. It can resist high-temperature corrosion conditions such as 850℃. 2. At the point where the fan drive shaft penetrates the volute, theoretically, the point is at the zero point where the positive and negative pressure curves intersect during fan operation. Both static and dynamic conditions must ensure no leakage at this point. For static conditions, this requires vacuuming and nitrogen purging before system operation to ensure oxygen isolation. For dynamic conditions, it is necessary to ensure that heat conduction does not damage the drive shaft and bearings at 850℃. Therefore, a cooling and sealing device is used, employing a gas-sealed chamber and a water-cooled chamber structure (e.g., ...). Figure 5 One end of the air-sealed chamber structure is connected to the fan casing via welding and ceramic packing, while the other end is connected to the water-cooled chamber structure via a shaft and ceramic packing. One end of the water-cooled chamber is connected to the air-sealed chamber via a shaft and carbon fiber packing, while the other end is connected to the bearing housing via a shaft and carbon fiber packing. During system operation, 0.06 MPa of nitrogen gas is introduced into the air-sealed chamber to ensure the fan casing is isolated from the atmosphere and simultaneously cools the drive shaft. After nitrogen and water cooling, the temperature of the bearing transmitted through the drive shaft to the bearing housing can be controlled below 100℃, ensuring long-term low-temperature operation of the bearing. In summary, through material selection and insulation structure design, the fan can be guaranteed to operate in a closed environment at 850℃.

[0019] Fifth, turn on the automatic nitrogen intake and exhaust device to control the system pressure at 2000Pa. Based on the 12-hour holding at 200℃, slowly heat to 850℃ and hold for 24 hours according to the heating rate of 10℃ / hour and the holding time process (increasing by 10°C every two hours). The frequency of the circulating fan is increased from 20Hz to 50Hz according to the design rate requirement of 3Hz / 24 hours. During this period, the flocculent material generated adheres to the filter in the circulating system and does not affect the silicon carbide heating device.

[0020] Step 6: Set the cooling process to a cooling rate of 10℃ / hour, and introduce room temperature nitrogen to reduce the furnace temperature from 850℃ to 600℃. Then, cool the furnace to 100℃ at a cooling rate of 20℃ / hour. Open the sealed door and pull the mold trolley out along the track to cool to room temperature in the atmosphere. Remove the glass carbon mold, and gently remove the glass carbon product from the mold using a plastic pry bar. Inspect the glass carbon for quality and store it in the warehouse. The glass carbon product has uniform thickness, a glossy black surface, and a room temperature resistance of approximately 0.1 ohms, almost zero.

[0021] Compared to existing technologies, this invention has the following advantages: It introduces a nitrogen-sealed circulation pyrolysis furnace system for producing glassy carbon products, a system not yet available domestically. The invention employs an external nitrogen circulation and filtration system, effectively solving the problem of production safety accidents caused by the adhesion of deposits to silicon carbide rods. The filtration device is equipped with a handhole and differential pressure monitoring instrument for easy cleaning of lint and debris blockage, and allows for prior observation of blockage conditions. A rectangular flange at the top of the filter facilitates the removal and installation of stainless steel wire mesh components for replacement or cleaning. The pyrolysis furnace uses a cylindrical body with a crown-shaped end cap structure, which can withstand both positive and negative pressure, and is easy to weld and process, saving costs. The door flange uses an internal water-cooled structure, effectively reducing the flange temperature to below 300℃, ensuring effective sealing of the gasket. The inlet and outlet airflow distributors ensure that the heating airflow within the pyrolysis furnace is in a laminar flow distribution state, with the hot airflow passing evenly and slowly through each mold layer, allowing the glassy carbon to absorb heat uniformly, which is beneficial for the formation of the carbonized structure. The use of mold leveling adjustment ensures that the resulting glassy carbon product has a uniform thickness. Two guide rails are installed inside the cylinder to facilitate the entry and exit of the mold carriage, allowing for the processing of eight glass carbon products at a time. The support legs utilize an aluminum silicate insulation structure to reduce heat transfer to the ground. The high-temperature fan employs an air-sealed and water-sealed chamber structure, effectively isolating oxygen and providing effective cooling for the drive shaft. The transmission box uses a double-bearing supported impeller cantilever structure, ensuring more reliable impeller rotation. The heating device uses silicon carbide rods, enabling rapid heating of the system to 850℃. Redundant silicon carbide rods address power compensation issues. An external 380V power supply connects to the silicon carbide rods inside the casing via sealed, insulated conductive posts. Inorganic sealant is applied between the casing and the conductive posts, achieving both insulation between the conductive wire and the casing and sealing of the connection point. A rectangular flange is installed at the top of the silicon carbide rod heater for top-level wiring. A PTFE gasket is placed between two rectangular flanges; after pre-tightening, it isolates the internal and external oxygen connections. The entire flow duct system (including elbows) is made of high-temperature resistant S310 stainless steel, capable of operating normally at 850℃, offering both high-temperature resistance and corrosion resistance. Elbows minimize the system's footprint by allowing the duct to bend, saving investment. Various tapered sections of different sizes ensure smooth and stable airflow as it flows into and out of the duct, resulting in uniform system temperature. The entire system possesses these advantages, and the system temperature can be heated to over 850℃. Through nitrogen purging to eliminate oxygen, it meets the process requirements for continuous glassy carbon production, producing qualified glassy carbon products. Simultaneously, it solves the problem of lint adhering to silicon carbide rods, ensuring the safe operation of the invented device. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 This is a schematic diagram of a steel mold structure.

[0024] Figure 3 Schematic diagram of nitrogen replacement of air within the system;

[0025] Figure 4 A schematic diagram showing the state of cooling water being circulated into the sealing flange of the pyrolysis furnace;

[0026] Figure 5 This is a schematic diagram of the cooling and sealing device.

[0027] In the diagram: 1-High-temperature fan, 11-Base, 12-Bearing housing, 13-Cooling and sealing device, 14-Impeller, 15-Volume, 16-Motor, 17-Coupling, 18-Reducer 1, 19-Reducer 2; 2-Duct, 21-Straight duct section, 22-Elbow; 3-Silicon carbide rod heating device, 31-Silicon carbide rod, 32-Positive electrode, 33-Negative electrode, 34-Three-phase sealed conductive column, 35-Reducer 3; 4-Airflow distributor, 41-Connecting flange, 42-Gas collecting cylinder; 5-Cracking furnace, 51-Sealing gasket, 52-Flange, 53-Fasting nut, 54-Fasting bolt, 55-External end cap, 56-Parallel guide rail, 57-Insulated support leg, 58-Cylinder body, 59-Connecting flange, 501-Airflow distribution plate; 6-Filter, 61-Connecting flange, 62-Filter mesh, 63-Handhole 64-Circular shell, 65-Variable diameter cone, 66-Adjusting bolt, 67-Support frame, 68-Ceramic plate, 69-Positioning frame, 70-Kraft paper, 71-Glass carbon, 72-Buffer tank, 73-Pressure regulating valve, 74-Flow meter, 75-Oxygen concentration detector, 76-Ceramic gasket, 77-Rubber gasket, 78-High temperature ceramic sealing ring, 79-External sealing flange, 80-Concave flange, 81-Cooling water outlet, 82-Annular cooling water channel, 83-Cooling water inlet, 84-Air inlet, 85-Air outlet, 86-Aluminum silicate insulation material, 87-Nitrogen inlet, 88-Water cooling device, 89-Water inlet, 90-Gas sealing device, 91-Volume, 92-Impeller, 93-Carbon fiber packing, 94-Water outlet, 95-Ceramic fiber packing, 96-Nitrogen outlet, 97-Inner head. Detailed Implementation

[0028] To enhance understanding of the present invention, the embodiments will be described in detail below with reference to the accompanying drawings.

[0029] Example 1: See Figure 1A nitrogen-circulating furan resin glass carbon pyrolysis furnace device is disclosed. The device includes a pyrolysis furnace body 5, a high-temperature fan 1, a silicon carbide rod heating device 3, an airflow distributor 4, an air duct 2, and a filter 6. An airflow distributor 4 is installed at both the front and rear ends of the pyrolysis furnace body 5. The rear end of the airflow distributor 4 of the pyrolysis furnace body 5 is connected to the filter 6, and the rear end of the filter 6 is connected to the high-temperature fan 1. The rear end of the high-temperature fan 1 is connected to the silicon carbide rod heating device 3, and the rear end of the silicon carbide rod heating device 3 is connected to the airflow distributor 4 at the front end of the pyrolysis furnace body 5. The air duct 2 connects all the above devices into a whole. The air duct 2 includes several straight sections 21 and three elbows 22. The straight sections and elbows of the air duct are made of S310 high-temperature alloy and are welded together. They are welded to the high-temperature fan, heating device, pyrolysis device, and filter device, forming a closed ring structure in a relatively small area. This allows the high-temperature hot airflow to flow within the air duct at a certain speed and direction, enabling accelerated and uniform heat transfer. Minimizing bends and straight pipe sections helps reduce the resistance to high-temperature airflow and minimize heat loss. The pyrolysis furnace body 5 includes a circular cylinder 58, with a crown-shaped end cap 55 of the same specification at each end. A flange 52 is welded between each crown-shaped end cap 55 and the cylinder 58. The two flanges 55 are connected by fastening bolts 54, fastening nuts 53, and sealing gaskets 51. The closed cavity structure of the circular cylinder and crown-shaped end caps ensures safe operation under negative pressure conditions. Compared with a rectangular cylinder structure, its local stress and membrane stress are much smaller and easier to manufacture, significantly improving operational safety and saving manufacturing time, materials, and costs. One end cap is connected to the cylinder by a pair of flanges for sealing, serving as a door for easy opening and closing, used for loading raw materials and recovering products. Considering the operating temperature of the cylinder reaches 850℃, the cylinder legs cannot directly contact the ground, as this would transfer a lot of heat. Cooling systems are installed inside the two flanges 55 to prevent high temperatures from damaging the flange seals. The cylinder 58 has two parallel guide rails 56 to support the glass carbon mold. An airflow distribution plate 501 is installed on the outer side of each parallel guide rail 56. Four connecting flanges 59 are located at the top of the cylinder 58, and four heat-insulating legs 57 are located at the bottom. Nine small holes are opened on each side of the cylinder 58 opposite the airflow distribution plate 501, connecting to the distribution pipe 43. The sealing flanges, after being pre-tightened with fasteners, tightly press the sealing gasket, capable of withstanding a gas pressure of 5000Pa without leakage. When the temperature rises to 850℃, heat will be transferred to these sealing flanges. If the temperature is not reduced, the entire sealing structure will immediately fail. Using internal water cooling for the flanges solves this problem. By adjusting the water flow, the temperature of the flange sealing structure can be kept below 300℃, effectively ensuring the sealing structure does not leak. This ensures that oxygen is effectively isolated during high-temperature operation.This invention involves the production of multiple glass carbon products. Each mold is placed horizontally as a single piece, and these multiple pieces are placed inside a pyrolysis furnace. Uniform furnace temperature is required, and each product must reach the same temperature. This necessitates the manufacture of a mold rack. The mold rack is designed as a wheeled trolley to store multiple layers of molds. Each layer of molds on the rack can be adjusted horizontally to ensure uniform thickness after product forming. Two parallel guide rails are installed inside the furnace cylinder, allowing the mold rack trolley to be pushed in and pulled out. To ensure uniform furnace temperature, the high-temperature gas entering from the side must be evenly distributed, and the outflowing gas must also be evenly distributed to achieve a uniform temperature field within the furnace cylinder. To ensure uniform gas distribution entering the furnace cylinder, a multi-port inlet and outlet structure is employed. This invention utilizes an aluminum silicate insulating block structure for the support legs, effectively blocking the transfer of high-temperature heat and maintaining the temperature at the contact point between the bottom of the support legs and the ground at approximately 30°C. The four flanges at the top of the cylinder are used for pressure controllers, nitrogen input, vacuuming, and high-temperature and high-pressure alarm interfaces. The high-temperature fan 1 has a base 11, on which a bearing housing 12, a motor 16, and a volute 15 are mounted. A coupling 17 is provided between the motor 16 and the drive shaft of the bearing housing 12. An impeller 14 is located inside the volute 15 and is connected to the drive shaft of the bearing housing 12. A cooling and sealing device 13 is provided on the side of the volute 15 and the bearing housing. A reducer 18 is provided at the airflow outlet of the volute 15, and a reducer 19 is provided at the airflow inlet of the volute 15. Both reducers 18 and 19 are connected to the air duct 21. The system of this invention operates at a maximum temperature of 850℃ and is isolated from the atmosphere. Ordinary high-temperature fans cannot meet the requirements of the system. The high temperature of the fan volute will inevitably be transmitted to the impeller, drive shaft, and the first bearing in the bearing housing. If cooling measures are not taken to cool the bearing to below 80℃, the bearing will be damaged in a short time, and the system will not be able to operate normally. The fan structure of this invention is supported by a base, and the motor is connected to the drive shaft via a coupling. The drive shaft is supported by double-end bearings, with one cantilever connected to the fan impeller. The impeller is surrounded by the fan casing, and the bearings are mounted on the fan base along with the motor via bearing housings. The bearing housings and motor are connected to the base via threaded connections. The bearings and drive shaft, as well as the bearings and bearing housings, are interconnected by interference fits. A cooling and sealing device is used between the casing and the bearing housing, employing a gas-sealed chamber and a water-cooled chamber structure. One end of the gas-sealed chamber is connected to the fan casing via welding and ceramic packing, while the other end is connected to the water-cooled chamber via a shaft and ceramic packing. One end of the water-cooled chamber is connected to the gas-sealed chamber via a shaft and carbon fiber packing, while the other end is connected to the bearing housing via a shaft and carbon fiber packing. Nitrogen gas at 0.08 MPa is introduced into the gas-sealed chamber to isolate the casing from the atmosphere and simultaneously cool the drive shaft. Cooling water at 0.2 MPa is introduced into the water seal chamber to cool the drive shaft. The inlet flow rate is adjusted to keep the outlet water temperature at 70℃.The volute, impeller, and drive shaft are made of S310 high-temperature resistant alloy material. Combined with the motor, coupling, drive shaft, bearing housing, cooling and sealing device, and base, they form a high-temperature fan unit. This unit operates under external circulation conditions up to 850℃, effectively transferring heat to the pyrolysis furnace, allowing the furan resin to absorb heat and carbonize. The silicon carbide rod heating device 3 has 20 U-shaped silicon carbide rods 31. Each rod 31 has a positive electrode 32 and a negative electrode 33 at its top. Three sealed conductive pillars 34 are located on the outside of the casing, and two reducing valves 35 are located on both sides of the casing. The two reducing valves 35 are connected to the air duct 21. The heat source for the 850℃ system temperature comes from the silicon carbide rod heating device. Ordinary metal tubular heaters, when powered by 380V AC, can only reach a surface temperature of 850℃. Through conduction and radiation with the surrounding air or nitrogen, they can only reach an ambient temperature of 650℃, which cannot meet the 850℃ carbonization process requirements. The silicon carbide rod heater is made of silicon carbide mixture and has the advantages of high temperature resistance, low high temperature resistance and high heating efficiency. The device adopts a U-shape. The silicon carbide rod heater, with a diameter of [diameter missing], uses 380V AC power and achieves a measured surface heating temperature of 1450℃. There are 24 U-shaped [types missing]. The heating device, composed of silicon carbide rod heaters of various diameters, has a total heating power of 168KW. When connected in parallel and supplied with 380V AC power, it can achieve a maximum system temperature of 1000℃, fully meeting the process temperature requirements. Twenty-four heaters of this model are connected in parallel, arranged in six rows of four, with a U-shaped configuration facing the wind direction. The last row is unconnected and reserved as a backup in case of failure. The silicon carbide rod heater body consists of a hot end and a cold end. When energized, the hot end heats up, converting electrical energy into heat energy, while the cold end acts as a conductive bridge. This invention features a 300mm long cold end and a 500mm long hot end. The cold end is inserted into a 250mm thick rigid aluminum silicate insulation board, extending 50mm out for mounting a butterfly-type wiring clamp. One end of the U-shaped silicon carbide rod is connected to the 380V A phase via the butterfly clamp, and the other end is connected to the B phase. A 380V AC voltage is formed between phases A and B to provide power to the silicon carbide rod. The 380V external AC power supply is connected to the silicon carbide rod inside the heater via three sealed and insulated conductive pillars. The insulated part of the conductive pillars is connected to the housing of the heating device, and inorganic sealant is used to seal the contact points with the housing, ensuring a leak-proof seal between the housing and the insulated conductive pillars. The top of the heater is sealed with a square flange and insulated with a 250mm rigid aluminum silicate heat insulation board, achieving a top temperature of 60℃. The flange sealing material is made of polytetrafluoroethylene, ensuring no leakage under 5000Pa pressure. The silicon carbide rod heater housing adopts a square cylindrical structure with two conical components at both ends, welded to the air ducts at both ends. The conical components serve to rectify and stabilize the flow. The inside of the cylindrical section is insulated with 300mm thick aluminum silicate heat insulation modules on both sides. The rigid aluminum silicate plate on top, which houses the silicon carbide rod heater, presses down on the aluminum silicate modules on both sides, forming a square channel within which the silicon carbide rod heater is installed. High-temperature nitrogen gas flows into the chamber through one end of a variable diameter circuit and is heated by the hot end of a silicon carbide rod heater. The silicon carbide rod surface, at a high temperature of 1450°C, exchanges heat with the nitrogen gas flow to obtain energy. After multiple cycles of heat absorption, the process temperature of the gas flow reaches 850°C. The gas flow distributor 4 is located at the inlet and outlet of the pyrolysis furnace body 5, and has a connecting flange 41 on the upper part for installing a temperature sensor. The gas collecting cylinder 42 is welded and sealed at both ends, with a large hole on one horizontal side in the middle for connecting to the air duct 21, and nine small holes on the other side for connecting to the distribution pipe 43. This invention adopts a one-to-nine inlet and outlet structure, effectively reducing the eddies, turbulence, and other airflow organization that are not conducive to uniform flow generated by gas entry and exit. When the nitrogen gas flows in, it first enters a gas collecting cylinder for volume expansion, and then is distributed into nine distribution pipes that simultaneously enter the pyrolysis furnace body, and then flows evenly through the distribution plate inside the cylinder. After passing through the glass carbon mold, the uniform fluid flows through the distribution plate and nine distribution pipes before converging into another air collection cylinder. It then returns to the negative pressure section of the fan through the return air pipe. This configuration ensures stable air pressure and uniform air velocity throughout the system, which is highly beneficial for uniform heating of the glass carbon mold.The interface flange at the top of the inlet and outlet air ducts is used to connect electrical control components such as temperature controllers, which feedback the thyristor circuit to adjust the output voltage to control the temperature of the nitrogen gas flow in the system. The filter 6 is provided with a circular housing 64, and two reduced-diameter cones 65 are provided on both sides of the circular housing 64. The small ends of the two reduced-diameter cones 65 are respectively connected to the air inlet and outlet air ducts 21. A manhole 63 is provided at the top of the reduced-diameter cone 65 at the air inlet end, and a connecting flange 61 is provided on each horizontal side of the reduced-diameter cone 65 at the air inlet and outlet ends. A filter wire mesh 62 is provided inside the circular housing 64. The filter provided in the present invention is mainly used to filter the floccules generated during the high-temperature operation of the system. A kind of oligomer fluff is generated during the high-temperature carbonization process of furan resin, and this fluff has the characteristics of small high-temperature resistance and easy conductivity. If the filter is not installed, the fluff will accumulate between the two poles heated by the silicon carbide rod heater for a long time, causing a short circuit and major safety accidents. In order to ensure the normal operation of the system equipment, measures to collect the fluff need to be taken to prevent the fluff from accumulating on the surface of the silicon carbide rod. The present invention adopts the method of stainless steel wire mesh filtration, and installs a wire mesh filter between the system air ducts to filter the fluff generated by the system. The wire mesh filter is installed in a circular cylinder, and a pair of rectangular flanges are installed at the top, so that the wire mesh component can be lifted out at any time for cleaning or replacement. The two reduced-diameter cones on both sides of the circular cylinder play a role in rectifying and stabilizing the flow of the circulating gas. A manhole is provided at the top of the reduced-diameter cone at the gas inlet end for facilitating the cleaning of the fluff on the wire mesh. A connecting flange is installed on each of the two cones at the gas inlet and outlet for installing a differential pressure detection instrument. If the differential pressure displayed by the instrument exceeds the set value, it indicates that the wire mesh filter of the system has been clogged by fluff, prompting cleaning or replacement. This technical solution uses the method of fan pressurization and nitrogen circulation, and consists of a variety of equipment such as a fan, air ducts, silicon carbide rod heating devices, cracking furnaces, filters, etc. to form a closed circulation system, and heats the circulating nitrogen in a temperature-time automatic control manner. The air flow organization is heated by the silicon carbide rod heating device from the outlet of the high-temperature fan, enters the high-temperature oven to heat the furan resin, then enters the wire mesh filter for filtration, and finally enters the negative pressure inlet of the fan for repeated circulation. The air inlet of the cracking furnace is welded to the air duct, the other end of the air duct is welded to the outlet air duct of the silicon carbide rod heating device, the air inlet of the silicon carbide rod heating device is welded to the air duct, the other end of the air duct is welded to the outlet air duct of the high-temperature fan, the air inlet of the high-temperature fan is welded to the air duct, the other end of the air duct is welded to the outlet air duct of the filter, the air inlet of the filter is welded to the air duct, and the other end of the air duct is welded to the outlet air duct of the cracking furnace, forming a closed system composed of multiple devices and multiple sections of air ducts. After the system is welded, a airtightness test of 5000Pa is carried out, and no bubbles are detected by soap water inspection, and it is qualified if the pressure is maintained for 12 hours without pressure drop.

[0030] Example 2: See Figure 1, Equipment manufacturing process: The flow-through material of the entire nitrogen circulation system is selected according to the S31008 material in GB24511-2017 "Stainless Steel Sheets and Strips for Pressure Equipment", which is required to resist high-temperature acid and alkali corrosion at temperatures above 850°C; the selection standard of external insulation materials. High-density aluminosilicate refractory fiber modules with a temperature resistance above 1000°C in GB / T3003-2017 "Refractory Fibers and Products", with a thickness of 300;

[0031] The filter uses the SP type laminated wire mesh in HG / T21618-1998 "Wire Mesh Demister", with a thickness of 150 and a material of S31008;

[0032] The silicon carbide rod is selected according to the equal-diameter type II silicon carbide rod in JB / T3890-2008 "Silicon Carbide Special Products - Silicon Carbide Rods", with a diameter of 25mm.

[0033] The fan is selected with a fully sealed structure that can withstand high temperatures above 1000°C, a air volume of 1800m 3 / h, a wind pressure of 2500Pa, and a power of 18.5KW. The fan meets the technical requirements of the ≥850° working condition in JB / T8822-2013 "Technical Conditions for High-Temperature Centrifugal Ventilators";

[0034] The designed internal volume of the cracking furnace is 1m 3 , and the outer dimensions are , the wall thickness uses 6mm plates, and the four legs use carbon steel steel pipes plus heat insulation blocks; the materials of the cracking furnace and the air duct system are designed and manufactured according to the requirements of NB / T47003.1-2009 "Steel Welded Atmospheric Pressure Vessels", and the materials meet the requirements of the S31008 material in GB24511-2017 "Stainless Steel Sheets and Strips for Pressure Equipment", with a fully welded closed system.

[0035] After the system is welded and assembled, a airtightness test of 5000Pa is carried out. Check with soap water for no bubbles, and it is qualified if the pressure holds for 12 hours without pressure drop.

[0036] The operating temperature of the nitrogen circulation furan resin glassy carbon cracking process can reach 850°C. To build a complete set of equipment, it needs to withstand high temperatures of 85°C. At the same time, the whole set of equipment is required to be corrosion-resistant and meet the requirements of the anaerobic atmosphere process. Therefore, the equipment manufacturing process is the basis for the safe operation of the whole set of equipment.

[0037] A method for producing glassy carbon products, the method comprising the following steps:

[0038] The first step is to inject the furan resin mucus into a specific steel mold (such as Figure 2The mold is placed in the pyrolysis furnace track frame to meet the shape requirements, and then the mold and ceramic plate are placed horizontally together. The sealing door of the pyrolysis furnace is then closed and locked. The specific steel mold is made of 304 stainless steel and must be level. The upper and lower planes of the ceramic plate must also be level. After the ceramic plate is placed in the positioning frame, it is initially leveled on a horizontal platform. After the mold is placed on the pyrolysis furnace guide rail frame, the bottom of the mold is leveled by four fine-tuning screws. During adjustment, a laser level is used to correct the level of the upper plane of the mold, and then a high-precision fitter's level is used for fine-tuning. The final levelness is controlled below 0.2%. The levelness of the track is corrected in the same way, and the final levelness is controlled below 0.2%. This ensures that the thickness tolerance of the product is controlled within 0.1mm during the curing process of glass carbon. After the ceramic plate is leveled as described above, oiled kraft paper is laid on the surface of the ceramic plate and the four sides are leveled. A certain amount of furan resin viscous liquid is weighed and poured into the top of the kraft paper. After about 2 hours, it can be horizontally filled around the mold.

[0039] The second step is to replace the air in the system with nitrogen (e.g., Figure 3 The nitrogen purity is required to be 99.99%. This is achieved at a pressure of 0.1 Pa and a temperature of 5 m... 3 After 10 replacements at a flow rate of / hour, when the oxygen concentration in the exhaust is measured to be below 0.2%, gradually close the inlet valve to adjust the flow meter flow rate to 3m³ / h. 3 / hour; at the same time, close the exhaust valve to keep the nitrogen pressure in the system at a nitrogen equilibrium state of 2000Pa, and the replacement is over; the lower the oxygen content of the circulating nitrogen in the system, the better the carbonization effect of the product.

[0040] The third step is to circulate cooling water (such as...) into the sealing flange of the pyrolysis furnace. Figure 4 To prevent high temperatures from damaging the pyrolysis furnace sealing flange and causing leakage, when the temperature inside the pyrolysis furnace reaches 850°C, the sealing surface temperature of the sealing flange reaches 800°C due to heat transfer. If the sealing flange assembly is not effectively cooled, the gasket will quickly fail. To ensure effective sealing, the inner and outer sealing flanges use an internal cavity design, through which cooling water is circulated to cool the flange, gasket, and fasteners to below 300°C, achieving effective sealing conditions.

[0041] Step 4: Start the circulating fan and run it at a low frequency of 20Hz. Start the electric heating device and slowly heat it to 200℃ according to the heating rate process requirements, and hold it at this temperature for 12 hours to allow it to slowly solidify and desolvate. The heating rate is 5℃ / hour, and the final temperature is set to 200℃. After reaching 200℃, hold it for 12 hours to complete the first stage of carbonization. The circulating fan is required to operate normally under conditions of 850℃. The following measures are taken: 1. The flow material and drive shaft are made of high-temperature resistant alloy stainless steel S31008. This material is commonly known as S310 or 2520 material. It has excellent properties such as high temperature and high strength, high temperature oxidation resistance, high temperature corrosion resistance, high temperature creep resistance, and high temperature strength preservation, as well as good weldability and processing performance. It is typically used in various high-temperature environments and in various high-temperature resistant components such as the duct system, fan casing, impeller, and drive shaft of this device. It can resist high-temperature corrosion conditions such as 850℃. 2. At the point where the fan drive shaft penetrates the volute, theoretically, the point is at the zero point where the positive and negative pressure curves intersect during fan operation. Both static and dynamic conditions must ensure no leakage at this point. For static conditions, this requires vacuuming and nitrogen purging before system operation to ensure oxygen isolation. For dynamic conditions, it is necessary to ensure that heat conduction does not damage the drive shaft and bearings at 850℃. Therefore, a cooling and sealing device is used, employing a gas-sealed chamber and a water-cooled chamber structure (e.g., ...). Figure 5 One end of the air-sealed chamber structure is connected to the fan casing via welding and ceramic packing, while the other end is connected to the water-cooled chamber structure via a shaft and ceramic packing. One end of the water-cooled chamber is connected to the air-sealed chamber via a shaft and carbon fiber packing, while the other end is connected to the bearing housing via a shaft and carbon fiber packing. During system operation, the air-sealed chamber is purged with 0.06 MPa of nitrogen to ensure the fan casing is isolated from the atmosphere and to cool the drive shaft. The water-cooled chamber is purged with 0.2 MPa of cooling water to further cool the drive shaft. After nitrogen and water cooling, the temperature of the bearings transmitted through the drive shaft to the bearing housing can be controlled below 100°C, ensuring long-term low-temperature operation of the bearings. Through the selection of packing material and the design of the insulation structure, the fan can operate in a closed environment at 850°C.

[0042] Fifth, turn on the automatic nitrogen intake and exhaust device to control the system pressure at 2000Pa. Based on the 12-hour holding at 200℃, slowly heat to 850℃ and hold for 24 hours according to the heating rate of 10℃ / hour and the holding time process (increasing by 10°C every two hours). The frequency of the circulating fan is increased from 20Hz to 50Hz according to the design rate requirement of 3Hz / 24 hours. During this period, the flocculent material generated adheres to the filter in the circulating system and does not affect the silicon carbide heating device.

[0043] Step 6: Set the cooling process to a cooling rate of 10℃ / hour, and introduce room temperature nitrogen to reduce the furnace temperature from 850℃ to 600℃. Then, cool the furnace to 100℃ at a cooling rate of 20℃ / hour. Open the sealed door and pull the mold trolley out along the track to cool to room temperature in the atmosphere. Remove the glass carbon mold, and gently remove the glass carbon product from the mold using a plastic pry bar. Inspect the glass carbon for quality and store it in the warehouse. The glass carbon product has uniform thickness, a glossy black surface, and a room temperature resistance of approximately 0.1 ohms, almost zero.

[0044] It should be noted that the above embodiments are not intended to limit the scope of protection of the present invention. Equivalent transformations or substitutions made based on the above technical solutions all fall within the scope of protection of the claims of the present invention.

Claims

1. A nitrogen-circulating furan resin glass carbon pyrolysis furnace apparatus, characterized in that, The device includes a pyrolysis furnace body (5), a high-temperature fan (1), a silicon carbide rod heating device (3), an airflow distributor (4), an air duct (2), and a filter (6). The pyrolysis furnace body (5) is equipped with an airflow distributor (4) at the front and rear ends respectively. The airflow distributor (4) located at the rear end of the pyrolysis furnace body (5) is connected to a filter (6). The rear end of the filter (6) is connected to a high-temperature fan (1). The rear end of the high-temperature fan (1) is connected to a silicon carbide rod heating device (3). The rear end of the silicon carbide rod heating device (3) is connected to the airflow distributor (4) at the front end of the pyrolysis furnace body (5). The air duct connects all the above devices into a whole. The pyrolysis furnace body (5) is provided with a circular cylinder (58), and each end of the cylinder (58) has a crown-shaped end cap (55) of the same specification. A flange (52) is welded between the crown-shaped end cap (55) and the cylinder (58). The two flanges (52) are connected by fastening bolts (54), fastening nuts (53) and sealing gaskets (51). A cooling system is installed inside the two flanges (52), and two parallel guide rails (56) are installed inside the cylinder (58) to support the glass carbon mold. An airflow distribution plate (501) is installed on the outside of each parallel guide rail (56). Four connecting flanges (59) are installed on the top of the cylinder (58), and four heat-insulating legs (57) are installed at the bottom of the cylinder (58). Nine small holes are opened on each side of the cylinder (58) directly opposite the airflow distribution plate (501) and are connected to the distribution pipe (43) respectively. The high-temperature fan (1) is provided with a base (11), on which a bearing housing (12), a motor (16), and a volute (15) are provided; a coupling (17) is provided between the motor (16) and the drive shaft of the bearing housing (12), and an impeller (14) is provided inside the volute (15). The impeller (14) is connected to the drive shaft of the bearing housing (12). A cooling sealing device (13) is provided on the side of the volute (15) and the bearing housing. A reducer (18) is provided at the airflow outlet of the volute (15), and a reducer (19) is provided at the airflow inlet of the volute (15). The reducer (18) and the reducer (19) are respectively connected to the straight section of the air duct (21). The air duct (2) includes a straight section (21) and an elbow (22), and there are a total of three air ducts. The silicon carbide heating device (3) is equipped with 20 U-shaped silicon carbide rods (31). The top of the silicon carbide rod (31) is equipped with a positive electrode (32) and a negative electrode (33). The outer shell is equipped with three sealed conductive pillars (34). The two sides of the shell are equipped with three-diameter reducers (35). The two three-diameter reducers (35) are connected to the straight section air duct (21). The airflow distributor (4) is located at the inlet and outlet of the pyrolysis furnace body (5). A connecting flange (41) is provided on the upper part for installing a temperature sensor. The gas collecting cylinder (42) is welded closed at both ends, with a large hole on one horizontal side in the middle for connection to the straight section air duct (21), and nine small holes on the other side for connection to the distribution pipe (43). The filter (6) is provided with a circular shell (64), and two variable diameter cones (65) are provided on both sides of the circular shell (64). The small ends of the two variable diameter cones (65) are respectively connected to the straight section air duct (21) of the air inlet and outlet. A hand hole (63) is provided at the top of the variable diameter cone (65) at the air inlet end. A connecting flange (61) is provided on the horizontal side of the variable diameter cone (65) at the air inlet and outlet ends. A filter screen (62) is provided inside the circular shell (64).

2. A method for producing glassy carbon products using the nitrogen-circulating furan resin glassy carbon pyrolysis furnace apparatus as described in claim 1, characterized in that, Includes the following steps: The first step involves injecting furan resin slurry into a specific steel mold to meet shape requirements. The mold, along with the liquid, is then placed horizontally within the pyrolysis furnace track frame. The pyrolysis furnace sealing door is then closed and locked. The specific steel mold is made of 304 stainless steel and must be level both vertically and horizontally. The ceramic plate must also be level both vertically and horizontally. After the ceramic plate is placed in the positioning frame, it is initially leveled on a horizontal platform. Once the mold is placed on the pyrolysis furnace guide frame, its level is adjusted using four fine-tuning screws between the bottom of the mold and the track frame. Laser leveling is required for this adjustment. The mold's upper surface is leveled using an instrument, followed by fine-tuning with a high-precision level to ensure the final levelness is below 0.2%. The track's levelness is corrected using the same method, also to ensure it's below 0.2%. This ensures that the thickness tolerance of the glass carbon product is controlled within 0.1mm during the curing process. After the ceramic plate is leveled as described above, oiled kraft paper is laid on the surface of the ceramic plate, and the four sides are leveled. A certain amount of furan resin viscous liquid is weighed and poured onto the top of the kraft paper. After about 2 hours, the mixture will horizontally fill the mold's perimeter. The second step is to replace the air in the system with nitrogen, requiring a nitrogen purity of 99.99%. This is done 10 times at a pressure of 0.1 Pa and a flow rate of 5 m³ / h. When the oxygen concentration in the exhaust gas is measured to be below 0.2%, the inlet valve is gradually closed to adjust the flow rate to 3 m³ / h. At the same time, the exhaust valve is closed to maintain the nitrogen pressure in the system at a nitrogen equilibrium state of 2000 Pa. The replacement process is then complete. The third step involves circulating cooling water through the pyrolysis furnace sealing flange to prevent high-temperature conduction from damaging the flange and causing leakage. When the temperature inside the pyrolysis furnace reaches 850°C, the sealing surface temperature of the flange reaches 800°C due to heat transfer. If the flange assembly is not effectively cooled, the gasket will quickly fail. To ensure an effective seal, the inner and outer sealing flanges are designed with internal cavities, through which cooling water is circulated to cool the flange, gasket, and fasteners to below 300°C, achieving an effective seal. Step 4: Start the circulating fan and run it at a low frequency of 20Hz. Start the electric heating device and slowly heat to 200°C according to the heating rate process requirements, and hold at this temperature for 12 hours to allow it to slowly solidify and desolvate. The heating rate is 5°C / hour, and the final temperature is set to 200°C. After reaching 200°C, hold for 12 hours to complete the first stage of carbonization. The circulating fan is required to operate normally under conditions of 850°C. The following measures are taken:

1. The flow material and drive shaft are made of high-temperature resistant alloy stainless steel S3. The system uses 1008 material and employs a cooling and sealing device. This device consists of an air-sealed chamber and a water-cooled chamber. One end of the air-sealed chamber is connected to the fan casing via welding and ceramic packing, while the other end is connected to the water-cooled chamber via a shaft and ceramic packing. One end of the water-cooled chamber is connected to the air-sealed chamber via a shaft and carbon fiber packing, while the other end is connected to the bearing housing via a shaft and carbon fiber packing. During system operation, 0.06 MPa of nitrogen is introduced into the air-sealed chamber to ensure the fan casing is isolated from the atmosphere and to cool the drive shaft. The water-cooled chamber is circulated with 0.2 MPa cooling water for further cooling of the drive shaft. After nitrogen and water cooling, the temperature of the bearings transmitted through the drive shaft to the bearing housing can be controlled below 100°C, ensuring long-term low-temperature operation. Through the selection of packing material and the design of the insulation structure, the fan can be guaranteed to operate in a closed environment at 850°C. Fifth, turn on the automatic nitrogen intake and exhaust device to control the system pressure at 2000Pa. Based on the 12-hour holding time at 200°C, slowly heat to 850°C and hold for 24 hours, increasing the heating rate and holding time by 10°C every two hours according to the process of 10°C / hour holding time. The frequency of the circulating fan is increased from 20Hz to 50Hz according to the design rate of 3Hz / 24 hours. During this period, the flocculent material generated will adhere to the filter in the circulating system and will not affect the silicon carbide heating device. Step 6: Set the cooling process to a cooling rate of 10°C / hour, introduce room temperature nitrogen to reduce the furnace temperature from 850°C to 600°C, and then cool the furnace to 100°C at a cooling rate of 20°C / hour. Open the sealed door and pull the mold trolley out along the track. Cool it to room temperature in the atmosphere, remove the glass carbon mold, and gently remove the glass carbon product from the mold with a plastic pry bar. Inspect the glass carbon for quality and put it into storage. The glass carbon product has a uniform thickness and a glossy black surface. The resistance value tested at room temperature is about 0.1 ohms, which is almost zero.

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