Carbonization pre-oxidation furnace based on waste heat recovery and pre-oxidation method for NFs forming

Abstract

The invention relates to the technical field of carbon fiber carbonization and pre-oxidation, and discloses a carbonization and pre-oxidation furnace based on waste heat recovery and a pre-oxidation method for NFs forming. In the continuous nanofiber bundle carbonization or pre-oxidation process, air pressure balance mechanisms are arranged at the two ends of each silk yarn conveying mechanism correspondingly, and tail gas recovery systems are located at tail gas recovery openings formed in the two ends of each silk yarn conveying mechanism correspondingly; the air pressure balance mechanism can maintain the same negative pressure as the tail gas recovery ports, tail gas is prevented from directly overflowing from the two ends of the silk thread conveying mechanism, the tail gas output from the carbonization pre-oxidation furnace body can be completely input into the waste heat recovery tank from the tail gas recovery ports, and protective gas is discharged after being treated and detected after being subjected to waste heat recovery in the waste heat recovery tank. Therefore, leakage of tail gas can be avoided, all the tail gas can be treated, and pollution to the external environment is avoided while the continuous carbonization or pre-oxidation process of the nanofiber bundles is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of carbon fiber carbonization preoxidation, and in particular to a carbonization preoxidation furnace based on waste heat recovery and a preoxidation method. Background Art

[0002] Carbonization pre-oxidation furnace is a special equipment for producing carbon fiber. It plays a vital role in the production of carbon fiber. Its main function is to pre-oxidize and carbonize organic fibers (such as polyacrylonitrile fibers, etc.); among them, in the production process of carbon fiber, pre-oxidation is a key step, involving a series of complex reactions such as cyclization, cross-linking, dehydrogenation and oxidation of molecular chains. The purpose of these reactions is to transform the fiber into a pyridine ring ladder structure that is thermally stable and has semiconductor resistance, thereby significantly improving the heat resistance, flame retardancy and conductivity of the fiber.

[0003] The pre-oxidation process is not only a key step in the production of carbon fiber, it is also a bridge that connects the precursor to the final carbon fiber. In a high-temperature carbonization environment under the protection of inert gas, the pre-oxidized fiber can maintain its fiber morphology and further carbonize to form a carbon fiber with a turbostratic graphite structure. If the pre-oxidation step is skipped, the linear molecular chain of the precursor breaks during the high-temperature pyrolysis process, and carbon fibers with sufficient strength cannot be formed, resulting in an extremely low carbonization rate.

[0004] Pre-oxidation of multilayer nanofibers (NFs) is a key step in the preparation process, by subjecting the nanofibers to heat treatment at high temperatures to improve their structure and properties. During the pre-oxidation of multilayer nanofibers, the main chemical reactions that occur include: dehydrogenation: hydrogen atoms in the fiber are removed during the pre-oxidation process, which helps to improve the thermal stability and mechanical properties of the fiber; cyclization: the linear molecular structure in the fiber is transformed into a cyclic structure, and this process is usually accompanied by the rearrangement and cross-linking of the molecular chain; oxidation: the fiber reacts with oxygen at high temperature to form oxides, which helps to further improve the thermal stability and corrosion resistance of the fiber; polymerization: in some cases, small molecules in the fiber may form larger molecular chains through polymerization, increasing the molecular weight and mechanical strength of the fiber. These chemical reactions work together to cause significant changes in the microstructure and macroscopic properties of the fiber, help to form a heat-resistant ladder structure, and improve the thermal stability of the fiber, thereby improving its applicability as a high-performance material.

[0005] The current carbonization pre-oxidation furnace tends to be designed in a continuous manner to improve production efficiency and product quality. Due to environmental protection requirements, tail gas containing a variety of harmful components, such as carbon monoxide, sulfide, nitrogen oxides, volatile organic compounds (VOCs), etc., will be produced during the carbonization pre-oxidation process. If these tail gas emissions are not properly treated, they will cause serious pollution to the environment and pose a threat to the health of operators; therefore, tail gas treatment is a very important part of the operation of the carbonization pre-oxidation furnace.

[0006] The current continuous design requires continuous pre-oxidation or carbonization of the nanofiber bundles, which will inevitably be accompanied by the opening of the furnace mouth of the carbonization pre-oxidation furnace, which will cause the exhaust gas generated by the high temperature of the carbonization pre-oxidation furnace to be discharged, easily causing serious pollution. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a carbonization pre-oxidation furnace based on waste heat recovery and a pre-oxidation method for NFs forming.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: A carbonization pre-oxidation furnace based on waste heat recovery, comprising a carbonization pre-oxidation furnace body, a gas supply system and an exhaust gas recovery system, wherein a heating chamber is arranged inside the carbonization pre-oxidation furnace body, and treatment chambers are arranged on the upper and lower sides of the heating chamber respectively; a wire conveying mechanism is arranged inside each treatment chamber, and both ends of the wire conveying mechanism can respectively pass through the carbonization pre-oxidation furnace body, and both ends of each wire conveying mechanism are respectively provided with a gas pressure balancing mechanism, and the exhaust gas recovery system is located at both ends of each wire conveying mechanism, and exhaust gas recovery ports are respectively arranged; the gas supply system can supply protective gas to the interior of the treatment chamber, and the protective gas passes through After the treatment chamber, the tail gas is input into the waste heat recovery tank from each tail gas recovery port. The protective gas is discharged after the waste heat is recovered in the waste heat recovery tank after treatment and detection. The heating chamber can supply heat to the two treatment chambers on the upper and lower sides respectively, and the wire conveying mechanism can convey the nanofiber bundles inside the corresponding treatment chamber. Under the conveyance of each wire conveying mechanism, the vertical distance between each nanofiber bundle and the top surface of the heating chamber is the same, and the linear speed of each nanofiber bundle conveyed inside the corresponding treatment chamber is the same, and each nanofiber bundle can be processed inside the carbonization pre-oxidation furnace body.

[0009] Preferably, a ceramic heater is provided inside the heating chamber, and the ceramic heater can provide heat to the two processing chambers at the same time; a heat spreader is provided on the side of the processing chamber close to the heating chamber, and the heat spreader can evenly conduct the heat of the heating chamber to one side of the processing chamber; inside the processing chamber, the temperature of each position at the same vertical distance from the upper surface of the heat spreader is kept consistent.

[0010] Preferably, the gas supply system includes a protective gas storage tank and a gas supply unit, and the protective gas storage tank can supply protective gas to the inside of the two processing chambers through the gas supply unit respectively; the gas supply unit includes a mounting frame and two gas storage boxes, and the mounting frame is arranged at the top of the carbonization pre-oxidation furnace body, and the two gas storage boxes are respectively installed inside the mounting frame; each of the gas storage boxes is respectively connected to the protective gas storage tank, and air supply fans are arranged on both sides of each gas storage box, and the air supply fans can supply protective gas to the inside of the processing chamber through the air supply pipe.

[0011] Preferably, the silk thread conveying mechanism comprises a plurality of conveying rollers, each of which is provided with a rubber conveying ring on the outside, and along the conveying direction of the silk thread conveying mechanism, the nanofiber bundle passes through the rubber conveying rings of the conveying rollers in sequence and are located in the same straight line; when the conveying rollers rotate synchronously, the rubber conveying rings can provide power for the nanofiber bundle to move forward along the conveying direction of the silk thread conveying mechanism through friction.

[0012] Preferably, a conveying pulley is provided on one side of the conveying roller, and the wire conveying mechanism also includes a driving pulley and a driving motor. A driving toothed belt is tensioned on the outer side of each of the conveying pulleys and the driving pulley, and the driving motor can synchronously drive each of the conveying pulleys to rotate by driving the driving toothed belt to rotate.

[0013] Preferably, each of the exhaust gas recovery ports is connected to the exhaust gas recovery pipe through the heat exchange pipe, and the heat exchange pipe can pass through the waste heat recovery tank. The exhaust gas collected inside the heat exchange pipe can exchange heat with the heat exchanger inside the waste heat recovery tank to recover the waste heat in the exhaust gas discharged from the treatment chamber.

[0014] Preferably, the air pressure balancing mechanism comprises a balancing outer cover, each of which is respectively sleeved on both ends of each of the wire conveying mechanisms, and each strand of the nanofiber bundle can first pass through the balancing outer cover and then enter and exit the processing chamber.

[0015] Preferably, a negative pressure fan is arranged inside the balancing outer cover, and a barometer is arranged inside each balancing outer cover and each exhaust gas recovery port. The power of the negative pressure fan can be adjusted according to the pressure difference between the corresponding balancing outer cover and the corresponding exhaust gas recovery port.

[0016] Preferably, after the heat exchange pipe passes through the waste heat recovery tank, the exhaust gas inside the heat exchange pipe can pass into the exhaust gas detection mechanism, and the exhaust gas detection mechanism can detect the pollutant content of the exhaust gas discharged from the heat exchange pipe; the exhaust gas detection mechanism can selectively transport the exhaust gas to the exhaust gas purification system and the gas supply system according to the pollutant content of the exhaust gas discharged from the heat exchange pipe.

[0017] A pre-oxidation method for NFs forming, using the above-mentioned carbonization pre-oxidation furnace based on waste heat recovery, comprises the following steps: Nanofiber bundles are prepared by electrospinning technology; protective gas is supplied to the interior of the processing chamber through a gas supply system, and heat is supplied to the two processing chambers on the upper and lower sides through a heating chamber to heat the interior of the two processing chambers to a pre-oxidation temperature; each strand of the nanofiber bundle is transported by each wire conveying mechanism and is pre-oxidized in the process of passing through the interior of the corresponding processing chamber inside a carbonization pre-oxidation furnace body.

[0018] Compared with the prior art, the present invention provides a carbonization pre-oxidation furnace based on waste heat recovery and a pre-oxidation method for NFs forming, which has the following beneficial effects: 1. In the carbonization pre-oxidation furnace based on waste heat recovery, under the transportation of each wire conveying mechanism, the vertical distance of the outer wall of the heating chamber of each strand of nanofiber bundle is the same, and the linear speed of each strand of nanofiber bundle conveyed in the corresponding processing chamber is the same, and each strand of nanofiber bundle can be processed inside the carbonization pre-oxidation furnace body; and in the continuous carbonization or pre-oxidation process of the nanofiber bundle, through the air pressure balance mechanism respectively arranged at both ends of each wire conveying mechanism, the exhaust gas recovery system is located at the exhaust gas recovery port respectively arranged at both ends of each wire conveying mechanism; the air pressure balance mechanism can maintain the same negative pressure as the exhaust gas recovery port, avoiding the exhaust gas from directly overflowing from both ends of the wire conveying mechanism, so that the exhaust gas output from the carbonization pre-oxidation furnace body can be completely input from each exhaust gas recovery port to the waste heat recovery tank, and the protective gas is discharged after being processed and tested after the waste heat is recovered in the waste heat recovery tank, thereby avoiding the leakage of exhaust gas, and all exhaust gas can be processed, while ensuring the continuity of the carbonization or pre-oxidation process of the nanofiber bundle, avoiding pollution to the external environment.

[0019] 2. This carbonization pre-oxidation furnace based on waste heat recovery, through the setting of various conveying rollers and the rubber conveying rings sleeved on the outside of each conveying roller, the driving motor can drive the toothed belt to rotate, synchronously drive the various conveying belt wheels to rotate synchronously, and drive the various conveying rollers to rotate synchronously. Each rubber conveying ring can provide power for the nanofiber bundle to move forward along the conveying direction of the silk thread conveying mechanism through friction, so as to stably convey the silk thread while ensuring that the moving speed inside the processing chamber remains constant, effectively ensuring the pre-oxidation and carbonization effect of the nanofiber bundle. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is one of the three-dimensional structural schematic diagrams of a carbonization pre-oxidation furnace based on waste heat recovery according to the present invention; Figure 2 This is a second schematic diagram of the three-dimensional structure of a carbonization pre-oxidation furnace based on waste heat recovery according to the present invention; Figure 3 It is a three-dimensional structural schematic diagram of a partial structure of a carbonization pre-oxidation furnace based on waste heat recovery of the present invention; Figure 4 It is a schematic cross-sectional structure diagram of a carbonization pre-oxidation furnace based on waste heat recovery according to the present invention; Figure 5 It is a schematic diagram of the three-dimensional structure of a gas supply unit of a carbonization pre-oxidation furnace based on waste heat recovery according to the present invention; Figure 6 It is a three-dimensional structural schematic diagram of a tail gas recovery port, a wire conveying mechanism and a gas pressure balance mechanism of a carbonization pre-oxidation furnace based on waste heat recovery according to the present invention; Figure 7 It is a three-dimensional structural schematic diagram of a wire conveying mechanism of a carbonization pre-oxidation furnace based on waste heat recovery according to the present invention.

[0021] In the figure: 1. Carbonization pre-oxidation furnace body; 11. Heating chamber; 12. Processing chamber; 121. Heat plate; 2. Gas supply system; 21. Protective gas storage tank; 22. Gas supply unit; 221. Mounting frame; 222. Gas storage box; 223. Air supply fan; 224. Air supply pipe; 3. Exhaust gas recovery system; 31. Exhaust gas recovery port; 311. Exhaust gas recovery pipeline; 32. Waste heat recovery tank; 33. Heat exchange pipeline; 34. Exhaust gas detection mechanism; 4. Wire conveying mechanism; 41. Conveying roller; 42. Rubber conveying ring; 43. Conveying pulley; 44. Driving pulley; 45. Driving motor; 46. Driving toothed belt; 5. Air pressure balance mechanism; 51. Balance cover; 52. Negative pressure fan. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] As introduced in the background technology, there are deficiencies in the prior art. In order to solve the above technical problems, the present application proposes a carbonization pre-oxidation furnace based on waste heat recovery and a pre-oxidation method for NFs forming.

[0024] Embodiment 1: See also Figure 1-Figure 7 A carbonization preoxidation furnace based on waste heat recovery comprises a carbonization preoxidation furnace body 1, a gas supply system 2 and an exhaust gas recovery system 3. A heating chamber 11 is arranged inside the carbonization preoxidation furnace body 1, and treatment chambers 12 are arranged on the upper and lower sides of the heating chamber 11; a wire conveying mechanism 4 is arranged inside the treatment chamber 12, and both ends of the wire conveying mechanism 4 can respectively pass through the carbonization preoxidation furnace body 1, and both ends of each wire conveying mechanism 4 are respectively provided with a gas pressure balancing mechanism 5, and the exhaust gas recovery system 3 is located at both ends of each wire conveying mechanism 4, and exhaust gas recovery ports 31 are respectively arranged; the gas pressure balancing mechanism 5 comprises a balancing outer cover 51, and each balancing outer cover 51 is respectively sleeved on both ends of each wire conveying mechanism 4, and each strand of nanofiber bundle can first pass through the balancing outer cover 51 and then enter and exit the treatment chamber 12; a negative pressure fan 52 is arranged inside the balancing outer cover 51, and each balancing outer cover 51 and each exhaust gas recovery port 31 are provided with a negative pressure fan 52. Each part is provided with a barometer, and the power of the negative pressure fan 52 can be adjusted according to the pressure difference between the corresponding balancing outer cover 51 and the corresponding exhaust gas recovery port 31; the gas supply system 2 can supply protective gas to the inside of the treatment chamber 12, and the protective gas is input into the waste heat recovery tank 32 from each exhaust gas recovery port 31 after passing through the treatment chamber 12. After the waste heat is recovered in the waste heat recovery tank 32, the protective gas is discharged after being processed and tested; the heating chamber 11 can supply heat to the two treatment chambers 12 on the upper and lower sides respectively, and the wire conveying mechanism 4 can convey the nanofiber bundles in the corresponding treatment chamber 12. Under the conveyance of each wire conveying mechanism 4, the vertical distance between each nanofiber bundle and the top surface of the heating chamber 11 is the same, and the linear speed of each nanofiber bundle conveyed in the corresponding treatment chamber 12 is the same, and each nanofiber bundle can be processed inside the carbonization pre-oxidation furnace body 1.

[0025] A ceramic heater is provided inside the heating chamber 11, which can provide heat to the two processing chambers 12 at the same time; a heat spreader 121 is provided on the side of the processing chamber 12 close to the heating chamber 11, and the heat spreader 121 can evenly conduct the heat of the heating chamber 11 to one side of the processing chamber 12; inside the processing chamber 12, the temperature of each position at the same vertical distance from the upper surface of the heat spreader 121 remains consistent.

[0026] The gas supply system 2 includes a protective gas storage tank 21 and a gas supply unit 22. The protective gas storage tank 21 can supply protective gas to the inside of the two processing chambers 12 through the gas supply unit 22 respectively; the gas supply unit 22 includes a mounting frame 221 and two gas storage boxes 222. The mounting frame 221 is arranged at the top of the carbonization pre-oxidation furnace body 1, and the two gas storage boxes 222 are respectively installed inside the mounting frame 221; each gas storage box 222 is respectively connected to the protective gas storage tank 21, and each gas storage box 222 is provided with an air supply fan 223 on both sides. The air supply fan 223 can supply protective gas to the inside of the processing chamber 12 through the air supply pipe 224.

[0027] In specific use, this carbonization pre-oxidation furnace based on waste heat recovery can be used alone as any one of the treatment processes of carbonization or pre-oxidation, or it can be used in series to continuously carry out the pre-oxidation and carbonization processes; Before the actual pre-oxidation and carbonization, firstly, protective gas is supplied to the two processing chambers 12 respectively through the gas supply system 2 (the type of protective gas is the proprietary protective gas corresponding to various nanofiber bundles, which will not be repeated here. The protective gas used for the nanofiber bundles used in this application is nitrogen), wherein the mounting frame 221 is arranged at the top of the carbonization pre-oxidation furnace body 1, and the two gas storage boxes 222 are respectively installed inside the mounting frame 221; each gas storage box 222 is respectively connected to the protective gas storage tank 21, and each gas storage box 222 is provided with an air supply fan 223 on both sides, and the air supply fan 223 can supply protective gas to the inside of the processing chamber 12 through the air supply pipe 224; Then, the nanofiber bundle prepared by the electrospinning technology passes through the corresponding processing chamber 12 through the wire conveying mechanism 4, and the ceramic heater inside the heating chamber 11 can provide heat to the two processing chambers 12 at the same time, and the heat plate 121 is set on the side of the processing chamber 12 close to the heating chamber 11. The heat plate 121 evenly conducts the heat of the heating chamber 11 to the side of the processing chamber 12, so that the temperature of each position in the processing chamber 12 that is equal to the vertical distance from the upper surface of the heat plate 121 is kept consistent, and the temperature inside the two processing chambers 12 is heated to a temperature that meets the requirements (in this embodiment, the preheating is adopted). The oxidation process is carried out at a temperature of 300°C, and the temperature at the conveying position of each strand of nanofiber bundle is about 260°C), and then the wire conveying mechanism 4 passes through the corresponding treatment chamber 12 at a certain linear speed (the linear speed is related to the temperature and size inside the treatment chamber 12, and the linear speed of the nanofiber bundle in the present application is 0.1m / s). Under the conveyance of each wire conveying mechanism 4, the vertical distance of each strand of nanofiber bundle from the outer wall of the heating chamber 11 is the same, and the linear speed of each strand of nanofiber bundle conveyed inside the corresponding treatment chamber 12 is the same, and each strand of nanofiber bundle can be processed inside the carbonization pre-oxidation furnace body 1; And during the continuous carbonization or pre-oxidation process of the nanofiber bundles, the exhaust gas recovery system 3 is located at the exhaust gas recovery ports 31 respectively arranged at the two ends of each wire conveying mechanism 4 through the air pressure balancing mechanism 5 respectively arranged at the two ends of each wire conveying mechanism 4; each balancing outer cover 51 is respectively sleeved on the two ends of each wire conveying mechanism 4, and each strand of nanofiber bundle can first pass through the balancing outer cover 51 and then enter and exit the processing chamber 12, and a negative pressure fan 52 is arranged inside the balancing outer cover 51, and a barometer is arranged inside each balancing outer cover 51 and each exhaust gas recovery port 31, and the power of the negative pressure fan 52 can be adjusted according to the corresponding pressure difference between the balancing outer cover 51 and the corresponding exhaust gas recovery port 31 to ensure that the pressure difference between the balancing outer cover 51 and the corresponding exhaust gas recovery port 31 is within a relatively stable range (the air pressure inside the balancing outer cover 51 is always greater than the air pressure inside the corresponding exhaust gas recovery port 31), so as to avoid the exhaust gas from directly overflowing from the two ends of the wire conveying mechanism 4 and avoiding pollution to the external environment.

[0028] It should be noted that the air pressure balance mechanism 5 also includes a central controller, and a signal transmission line is set between the barometers connected to the balance cover 51 and the exhaust gas recovery port 31 and the central controller. The barometer monitors the air pressure values ​​of the balance cover 51 and the exhaust gas recovery port 31 in real time and transmits these data to the central controller. A specific algorithm program is preset inside the central controller, and the program can calculate the air pressure difference based on the two received air pressure values.

[0029] At the same time, the central controller is connected to the power regulating device of the negative pressure fan 52, and the power regulating device of the negative pressure fan 52 can be a frequency converter or other equipment that can change the input power of the motor. The central controller sends instructions to the power regulating device of the negative pressure fan 52 according to the preset logical relationship based on the calculated air pressure difference, so as to achieve precise adjustment of the power of the negative pressure fan 52. For example, when the air pressure difference is greater than the preset upper limit value, the central controller will send an instruction to reduce the power of the negative pressure fan 52 to the power regulating device of the negative pressure fan 52, so that the negative pressure in the balance cover 51 is appropriately reduced to reduce the air pressure difference; when the air pressure difference is less than the preset lower limit value, it will send an instruction to increase the power of the negative pressure fan 52 to increase the negative pressure in the balance cover 51 until the air pressure difference returns to an appropriate range.

[0030] The exhaust gas output from the carbonization pre-oxidation furnace body 1 can be completely input into the waste heat recovery tank 32 from each exhaust gas recovery port 31. The protective gas is discharged after being processed and tested after the waste heat is recovered in the waste heat recovery tank 32, thereby avoiding the leakage of the exhaust gas. All the exhaust gas can be processed, and while ensuring the continuity of the nanofiber bundle carbonization or pre-oxidation process, the pollution to the external environment is avoided.

[0031] Embodiment 2: See also Figure 1-Figure 4 , Figure 5-Figure 7 , which is different from the above-mentioned embodiment, is that the wire conveying mechanism 4 comprises a plurality of conveying rollers 41, each of which is sleeved with a rubber conveying ring 42 on the outside. Along the conveying direction of the wire conveying mechanism 4, the nanofiber bundle passes through the rubber conveying rings 42 of the conveying rollers 41 in sequence and are located on the same straight line. When the conveying rollers 41 rotate synchronously, the rubber conveying rings 42 can provide power for the nanofiber bundle to move forward along the conveying direction of the wire conveying mechanism 4 through friction.

[0032] A conveying pulley 43 is provided on one side of the conveying roller 41. The wire conveying mechanism 4 also includes a driving pulley 44 and a driving motor 45. A driving toothed belt 46 is tensioned on the outside of each conveying pulley 43 and the driving pulley 44. The driving motor 45 can drive the driving toothed belt 46 to rotate, thereby synchronously driving each conveying pulley 43 to rotate synchronously.

[0033] Through the arrangement of each conveying roller 41 and the rubber conveying ring 42 sleeved on the outside of each conveying roller 41, the driving motor 45 can drive the toothed belt 46 to rotate, synchronously drive each conveying pulley 43 to rotate synchronously, and drive each conveying roller 41 to rotate synchronously. Each rubber conveying ring 42 can provide power for the nanofiber bundle to move forward along the conveying direction of the silk thread conveying mechanism 4 through friction, so as to stably convey the silk thread while ensuring that the moving speed inside the processing chamber 12 remains constant, thereby effectively ensuring the pre-oxidation and carbonization effect of the nanofiber bundle.

[0034] Embodiment three: See also Figure 1-Figure 5 The difference from the above embodiment is that each exhaust gas recovery port 31 is connected to the heat exchange pipe 33 through the exhaust gas recovery pipe 311, the heat exchange pipe 33 can pass through the waste heat recovery tank 32, and the exhaust gas collected inside the heat exchange pipe 33 can exchange heat with the heat exchanger inside the waste heat recovery tank 32 to recover the waste heat in the exhaust gas discharged from the treatment chamber 12.

[0035] After the heat exchange pipe 33 passes through the waste heat recovery tank 32, the exhaust gas inside the heat exchange pipe 33 can pass into the exhaust gas detection mechanism 34, and the exhaust gas detection mechanism 34 can detect the pollutant content of the exhaust gas discharged from the heat exchange pipe 33; the exhaust gas detection mechanism 34 can selectively transport the exhaust gas to the exhaust gas purification system and the gas supply system 2 according to the pollutant content of the exhaust gas discharged from the heat exchange pipe 33.

[0036] Each tail gas recovery port 31 is connected to the heat exchange pipe 33 through the tail gas recovery pipe 311. The heat exchange pipe 33 can pass through the waste heat recovery tank 32. The tail gas collected in the heat exchange pipe 33 can exchange heat with the heat exchange agent in the waste heat recovery tank 32 to recover the waste heat in the tail gas discharged from the treatment chamber 12. After the heat exchange pipe 33 passes through the waste heat recovery tank 32, the tail gas in the heat exchange pipe 33 can pass into the tail gas detection mechanism 34. The tail gas detection mechanism 34 can detect the pollutant content of the tail gas discharged from the heat exchange pipe 33; the tail gas detection mechanism 34 can detect the pollutant content of the tail gas discharged from the heat exchange pipe 33. According to the pollutant content of the exhaust gas discharged from the heat exchange pipe 33, the exhaust gas is selectively transported to the exhaust gas purification system and the gas supply system 2. While being able to recover the extra heat dissipated to the exhaust gas due to pre-oxidation and carbonization, the exhaust gas can be processed and tested to ensure that the exhaust gas that meets the conditions of the exhaust gas detection mechanism 34 can be reused as a protective gas, and the exhaust gas that does not meet the conditions can be processed and reused as a protective gas, thereby reducing the waste of protective gas and avoiding the contamination of the pre-oxidation and carbonization process of the nanofiber bundle by excessive pollutants in the protective gas.

[0037] Embodiment 4: A pre-oxidation method for NFs forming comprises the following steps: Preparation of nanofibers: Polyacrylonitrile (PAN) or other types of nanofibers are prepared using electrospinning techniques; these fibers are usually dissolved in an organic solvent and then spun through a high voltage electric field to form a continuous nanofiber bundle; A pre-preparation of a carbonization pre-oxidation furnace based on waste heat recovery: a protective gas is supplied to the interior of a treatment chamber 12 through a gas supply system 2, and heat is supplied to the two treatment chambers 12 on the upper and lower sides through a heating chamber 11, so that the interiors of the two treatment chambers 12 are heated to a pre-oxidation temperature; wherein the pre-oxidation process is usually carried out in a specific gas environment, such as a nitrogen or inert gas environment (nitrogen is used in this embodiment) to avoid premature oxidation.

[0038] Pre-oxidation process: Each strand of nanofiber bundle is transported by each wire transport mechanism 4 and is pre-oxidized in the process of passing through the corresponding treatment chamber 12 in the carbonization pre-oxidation furnace body 1 (the pre-oxidation time in the furnace is 80-100 minutes). In the pre-oxidation process, non-carbon elements in the fiber are removed, the rearrangement of the internal structure of the fiber is promoted, and a more stable chemical structure is formed. The fibers of the nanofiber bundle undergo chemical reactions such as cyclization, dehydrogenation, oxidation and cracking to form a stable trapezoidal structure. Pre-oxidation can also reduce the amount of gas released by the fiber in the subsequent carbonization process, reduce internal stress and thermal shrinkage, so as to obtain a nanofiber bundle with high thermal stability and mechanical properties; Cooling: After pre-oxidation treatment, the nanofiber bundle needs to be cooled under controlled conditions to avoid stress concentration and fiber damage caused by rapid cooling.

[0039] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A carbonization pre-oxidation furnace based on waste heat recovery, comprising a carbonization pre-oxidation furnace body, a gas supply system and a tail gas recovery system, characterized in that: A heating chamber is arranged inside the carbonization pre-oxidation furnace body, and treatment chambers are arranged on the upper and lower sides of the heating chamber respectively; The processing chamber is provided with a wire conveying mechanism, and the two ends of the wire conveying mechanism can respectively pass through the carbonization pre-oxidation furnace body, and the two ends of each wire conveying mechanism are respectively provided with a gas pressure balance mechanism, and the tail gas recovery system is located at the two ends of each wire conveying mechanism, and the tail gas recovery port is respectively provided; The air pressure balancing mechanism includes a balancing outer cover, each of which is respectively sleeved on both ends of each of the silk thread conveying mechanisms, and each strand of the nanofiber bundle can first pass through the balancing outer cover and then enter and exit the processing chamber; a negative pressure fan is arranged inside the balancing outer cover, and a barometer is arranged inside each of the balancing outer covers and each of the exhaust gas recovery ports, and the power of the negative pressure fan can be adjusted according to the air pressure difference between the corresponding balancing outer cover and the corresponding exhaust gas recovery port; The gas supply system can supply protective gas to the interior of the processing chamber. After passing through the processing chamber, the protective gas is input into the waste heat recovery tank from each tail gas recovery port. After the waste heat is recovered in the waste heat recovery tank, the protective gas is processed and tested before being discharged. The heating chamber can supply heat to the two processing chambers on the upper and lower sides respectively, and the wire conveying mechanism can convey the nanofiber bundles inside the corresponding processing chamber. Under the conveyance of each wire conveying mechanism, the vertical distance between each nanofiber bundle and the top surface of the heating chamber is the same, and the linear speed of each nanofiber bundle conveyed inside the corresponding processing chamber is the same, and each nanofiber bundle can be processed inside the carbonization pre-oxidation furnace body.

2. A carbonization pre-oxidation furnace based on waste heat recovery according to claim 1, characterized in that: A ceramic heater is arranged inside the heating chamber, and the ceramic heater can provide heat to the two processing chambers at the same time; A heat spreader is provided on one side of the processing chamber close to the heating chamber, and the heat spreader can evenly conduct the heat of the heating chamber to one side of the processing chamber; Inside the processing chamber, the temperatures of various positions that are at equal vertical distances from the upper surface of the heat spreader are kept consistent.

3. A carbonization pre-oxidation furnace based on waste heat recovery according to claim 2, characterized in that: The gas supply system comprises a protective gas storage tank and a gas supply unit, and the protective gas storage tank can supply protective gas to the inside of the two processing chambers respectively through the gas supply unit; The gas supply unit comprises a mounting frame and two gas storage boxes, wherein the mounting frame is arranged at the top of the carbonization pre-oxidation furnace body, and the two gas storage boxes are respectively installed inside the mounting frame; Each of the air storage boxes is communicated with the protective gas storage tank, and air supply fans are arranged on both sides of each of the air storage boxes. The air supply fans can supply protective gas to the interior of the processing chamber through an air supply pipe.

4. The carbonization pre-oxidation furnace based on waste heat recovery according to claim 1, characterized in that: The wire conveying mechanism comprises a plurality of conveying rollers, each of which is sleeved with a rubber conveying ring on the outside, and along the conveying direction of the wire conveying mechanism, the nanofiber bundle passes through the rubber conveying rings of the conveying rollers in the same straight line in sequence; When the conveying rollers rotate synchronously, the rubber conveying rings can provide power for the nanofiber bundle to move forward along the conveying direction of the wire conveying mechanism through friction.

5. A carbonization pre-oxidation furnace based on waste heat recovery according to claim 4, characterized in that: A conveying pulley is arranged on one side of the conveying roller, and the wire conveying mechanism also includes a driving pulley and a driving motor. A driving toothed belt is tensioned on the outer side of each of the conveying pulleys and the driving pulley, and the driving motor can synchronously drive each of the conveying pulleys to rotate by driving the driving toothed belt to rotate.

6. The carbonization pre-oxidation furnace based on waste heat recovery according to claim 1, characterized in that: Each of the exhaust gas recovery ports is connected to the heat exchange pipe through the exhaust gas recovery pipe. The heat exchange pipe can pass through the waste heat recovery tank. The exhaust gas collected inside the heat exchange pipe can exchange heat with the heat exchanger inside the waste heat recovery tank to recover the waste heat in the exhaust gas discharged from the treatment chamber.

7. A carbonization pre-oxidation furnace based on waste heat recovery according to claim 6, characterized in that: After the heat exchange pipe passes through the waste heat recovery tank, the exhaust gas inside the heat exchange pipe can pass into the exhaust gas detection mechanism, and the exhaust gas detection mechanism can detect the pollutant content of the exhaust gas discharged from the heat exchange pipe; The exhaust gas detection mechanism can selectively deliver the exhaust gas to the exhaust gas purification system and the gas supply system according to the pollutant content of the exhaust gas discharged from the heat exchange pipeline.

8. A pre-oxidation method for NFs forming, using a carbonization pre-oxidation furnace based on waste heat recovery as described in any one of claims 1 to 7, characterized in that: The steps include: Nanofiber bundles were prepared using electrospinning technology; The protective gas is supplied to the interior of the processing chamber through the gas supply system, and the heat is supplied to the two processing chambers on the upper and lower sides through the heating chamber, so that the interiors of the two processing chambers are heated to the pre-oxidation temperature; Each strand of nanofiber bundle is transported by each wire transport mechanism and is pre-oxidized in the process of passing through the corresponding processing chamber inside the carbonization pre-oxidation furnace body.

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