Wide-mouth graphitization furnace
By designing a wide-mouth graphitization furnace, using splicing structure and induction heating technology, the existing graphitization furnace production capacity and life problems have been solved, efficient and stable carbon fiber production has been achieved, and the needs of high-end fields have been met.
Patent Information
- Application Number
- CN202422032189.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-21
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2034-08-21
AI Technical Summary
The furnace port width of the existing graphitization furnace is limited, which cannot meet the demand for high production capacity. The graphite heating body has a short life at high temperatures, so it is impossible to achieve continuous multi-temperature heating, resulting in insufficient production efficiency and stability of polyacrylonitrile-based high-strength high-mode carbon fibers.
A wide-mouth graphitization furnace is designed. The furnace is spliced by multiple furnace segments and adopts induction heating type. The induction coil surrounds the outer circumference of the furnace and is equipped with an electromagnetic shielding structure to achieve continuous multi-temperature heating, and optimize the furnace thickness and material selection to improve heat resistance and stability.
It achieves high-capacity and low-cost graphitization treatment, extends the service life of the graphitization furnace, meets the needs of continuous multi-temperature heating, and improves the production efficiency and stability of polyacrylonitrile-based high-strength high-mode carbon fibers.
Smart Images
Figure CN223150710U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of carbon fiber, in particular to a wide-mouth graphitization furnace. Background Technique
[0002] Polyacrylonitrile-based high-strength and high-modulus carbon fiber refers to carbon fiber with a carbon content of more than 99%. Polyacrylonitrile-based high-strength and high-modulus carbon fiber not only has the characteristics of high specific modulus and high specific strength, but also has excellent properties such as small thermal expansion coefficient, good thermal stability, and dimensional stability. It is widely used in fields such as spacecraft and aerospace.
[0003] Polyacrylonitrile-based high-strength and high-modulus carbon fiber is obtained by subjecting the fiber after high-temperature carbonization treatment to high-temperature graphitization treatment. However, the highest tensile modulus of the currently prepared high-strength and high-modulus carbon fiber is far from the theoretical modulus, and there are problems such as difficulty in simultaneously improving the tensile strength and tensile modulus performance, many fiber flyings, and poor stability, which cannot meet the requirements of high-end fields such as aerospace.
[0004] The preparation of polyacrylonitrile-based high-strength and high-modulus carbon fiber is the integration of high-temperature equipment (i.e., ultra-high-temperature graphitization furnace) and high-temperature technology. Among them, the continuous graphitization furnace commonly used in the industrial production process of polyacrylonitrile-based high-strength and high-modulus carbon fiber is a resistance furnace, and its structure includes a furnace body shell, a graphite heating element, a furnace chamber, heat insulation materials, etc. However, the existing resistance-type graphitization furnace has at least the following technical problems:
[0005] (1) During the industrial production process, the furnace mouth width of the continuous ultra-high-temperature graphitization furnace used is less than 1 m, and the furnace mouth width of the continuous graphitization furnace used by most enterprises is 0.1 - 0.6 m. There are few wide-mouth graphitization furnaces in the prior art. On the one hand, it is due to the size limitation of the commercially available furnace chamber materials (graphite materials). Beyond a certain size, there are no commercially available related materials. On the other hand, in the high-temperature graphitization environment, as the furnace mouth width increases, the graphite furnace chamber is prone to fracture due to the increase in the span.
[0006] It should be noted here that the fiber after high-temperature carbonization treatment is prepared from polyacrylonitrile precursor filaments through a pre-oxidation furnace, a low-temperature carbonization furnace, and a high-temperature carbonization furnace. In the prior art, the pre-oxidation furnace, the low-temperature carbonization furnace, and the high-temperature carbonization furnace can all be made with a wide mouth (currently, the wire passing width of a carbon fiber production line with a standard single-line production capacity of 2000-3000 tons is about 3.0 m). However, due to technical barriers in the graphitization furnace (see the previous paragraph), it is impossible to achieve wide-mouth production (the basic width is within 0.6 m). During industrial production, since the equipment in the previous process is a wide-mouth furnace and the graphitization furnace is a narrow-mouth furnace, the production capacity of the fiber after high-temperature carbonization treatment is relatively high, and the graphitization furnace cannot match the production capacity of the fiber after high-temperature carbonization treatment, resulting in a reduction in the annual production capacity of polyacrylonitrile-based high-strength and high-modulus carbon fibers. Using a wide-mouth graphitization furnace can further increase the production capacity of single-line polyacrylonitrile-based high-strength and high-modulus carbon fibers, and at the same time can further reduce production costs, enabling batch, continuous, and stable preparation of polyacrylonitrile-based high-strength and high-modulus carbon fibers.
[0007] Therefore, there is an urgent need for a graphitization furnace with a long lifespan and a wide mouth at present.
[0008] (2) In a high-temperature graphitization environment, the graphite heating element is continuously consumed due to oxidation and sublimation and can operate stably for 1 year at a temperature of 2650 °C. When the graphitization temperature exceeds 2800 °C, the loss of the graphite heating element increases sharply, and the lifespan of the heating element is significantly reduced, and its stable operation time is less than 7 days (it should be noted here that the furnace chamber reaches the set temperature by heating with the graphite body. When the furnace chamber reaches the set temperature, the temperature of the graphite body is higher than the set temperature and is very likely to exceed 2800 °C).
[0009] Although, when preparing polyacrylonitrile-based high-strength and high-modulus carbon fibers in the laboratory, an induction graphitization furnace that generates eddy current heating by induction is used. However, most of such heat source graphitization furnaces are intermittent graphitization furnaces or single-tube continuous graphitization furnaces, and only one temperature zone can be achieved in one graphitization furnace; during the graphitization process, multiple graphitization furnaces need to be connected in series to meet the multi-temperature zone graphitization process requirements. However, in this way, the different temperature zones are not continuous, and there will be cold zones between them (the cold zones formed by the interval between coming out of one graphitization furnace and then entering another graphitization furnace), so it cannot meet the requirements for large-scale and continuous preparation of polyacrylonitrile-based high-strength and high-modulus carbon fibers. Utility Model Content
[0010] In view of this, the present utility model provides a wide-mouth graphitization furnace, and the main purpose is to provide a graphitization furnace with a long lifespan and a wide mouth.
[0011] To achieve the above object, the present utility model mainly provides the following technical solutions:
[0012] On the one hand, an embodiment of the present utility model provides a wide-mouth graphitization furnace, wherein the wide-mouth graphitization furnace includes a furnace chamber; wherein, the furnace mouth width W of the furnace chamber is greater than 1 m; wherein, the furnace chamber is formed by sequentially splicing a plurality of furnace chamber segments; wherein, each furnace chamber segment includes:
[0013] A top plate;
[0014] A bottom plate, the bottom plate and the top plate are oppositely arranged;
[0015] A first arc-shaped side plate, a first side of the first arc-shaped side plate is butted against a first side of the top plate, and a second side of the first arc-shaped side plate is butted against a first side of the bottom plate;
[0016] A second arc-shaped side plate, a first side of the second arc-shaped side plate is butted against a second side of the top plate, and a second side of the second arc-shaped side plate is butted against a second side of the bottom plate;
[0017] Wherein, the first side and the second side are two oppositely arranged sides.
[0018] Preferably, through the top plate, the bottom plate, the first arc-shaped side plate and the second arc-shaped side plate, the cross-section of the furnace chamber segment forms a flat annular structure; and / or the shape of the furnace mouth of the furnace chamber is a flat annular opening.
[0019] Preferably, the first arc-shaped side plate is a U-shaped plate, and the second arc-shaped side plate is a U-shaped plate.
[0020] Preferably, a first side of the first arc-shaped side plate is butted against a first side of the top plate through a first connecting plate, and a second side of the first arc-shaped side plate is butted against a first side of the bottom plate through a second connecting plate; a first side of the second arc-shaped side plate is butted against a second side of the top plate through a third connecting plate, and a second side of the second arc-shaped side plate is butted against a second side of the bottom plate through a fourth connecting plate.
[0021] Preferably, the thickness K of the furnace chamber and the designed temperature T of the highest temperature zone of the graphitization furnace need to satisfy the following relationship:
[0022] When T < 2800 °C, K = 30 - 45 mm;
[0023] When 2800 °C ≤ T ≤ 3200 °C, K = 0.2593 × e 0.0019×T ;
[0024] Wherein, the unit of K is mm, and the unit of T is °C.
[0025] Preferably, the graphitization furnace is an induction heating type graphitization furnace; wherein, the inner cavity of the furnace chamber includes a plurality of temperature sections that are successively continuous; wherein, the number of the furnace chamber sections is the same as and corresponds one-to-one to the number of the temperature sections; the wide-mouth graphitization furnace further includes an induction coil; wherein, the induction coil is arranged around the outer periphery of the furnace chamber and is used to generate an induced current in the furnace chamber to heat the furnace chamber; wherein, the induction coil includes a plurality of induction coil sections; wherein, the number of the induction coil sections is the same as the number of the temperature sections, and each induction coil section is arranged around its corresponding temperature section to heat its corresponding temperature section; wherein, an electromagnetic shielding structure is arranged between any two adjacent induction coil sections to prevent the magnetic induction lines of any two adjacent temperature sections from influencing each other.
[0026] Preferably, the inner cavity of the furnace chamber has a wire threading channel, so that the fibers to be graphitized are successively and continuously passed through a plurality of temperature sections.
[0027] Preferably, the material of the electromagnetic shielding structure is selected as a set material; wherein, in an inert atmosphere, the set material can withstand a temperature of ≥3000 °C.
[0028] Preferably, the electromagnetic shielding structure is formed by overlapping at least two layers of carbon fiber cloth; or the electromagnetic shielding structure is formed by alternately overlapping carbon fiber cloth and tungsten mesh in sequence, wherein the outer layer of the electromagnetic shielding structure is carbon fiber cloth.
[0029] Preferably, the electromagnetic shielding structure is an electromagnetic shielding plate; and / or an electromagnetic shielding structure is provided between any two adjacent furnace sections; through holes for fibers to pass through are formed in the electromagnetic shielding structure; and / or the induction coil sections are wound around the outer periphery of the furnace; wherein, the induction coil sections are in a flat ring structure; and / or the material of the furnace is graphite. The number of temperature zones is greater than 1 and less than or equal to 9; and / or a heat insulation material is filled between the furnace and the induction coil; preferably, the heat insulation material is a high-temperature resistant graphite carbon felt; and / or the induction coil is installed on an insulating skeleton; preferably, the material of the insulating skeleton is refractory mortar; preferably, soft magnetic materials are uniformly distributed in the insulating skeleton to play a magnetic choking effect; and / or the graphitization furnace includes a furnace shell; the furnace and the induction coil are both located inside the furnace shell; the gaps between the furnace shell and the furnace and the induction coil are filled with heat insulation materials; and / or the graphitization furnace further includes: a controller and a temperature measuring device; wherein, the numbers of the controller and the temperature measuring device are the same as the number of temperature zones and correspond one by one; preferably, the temperature measuring device is used to measure the temperature of the corresponding temperature zone; the controller is connected to the corresponding temperature measuring device and the induction coil section; and / or detachable plugs are provided at both the inlet and outlet of the graphitization furnace to prevent heat radiation; and / or an electromagnetic shielding structure is also provided on the side of the first induction coil section close to the inlet of the graphitization furnace along the wire running direction; an electromagnetic shielding structure is also provided on the side of the last induction coil section close to the outlet of the graphitization furnace.
[0030] Compared with the prior art, a graphitization furnace of the present invention, as well as a high-strength and high-modulus carbon fiber and a preparation method thereof, at least have the following beneficial effects:
[0031] The wide-mouth graphitization furnace provided by the embodiment of the present invention, by designing the furnace into a structure formed by sequentially splicing a plurality of furnace sections, and at the same time, each furnace section is designed into a structure formed by splicing a top plate, a bottom plate, a first arc-shaped side plate, and a second arc-shaped side plate. Such a setting, on the one hand, for the selection of furnace materials (graphite materials), large sizes are not required, thus reducing costs; on the other hand, the stress situation of the furnace is optimized, and on the same span, it can withstand greater internal stress, thus avoiding the problem that the furnace is prone to fracture in a high-temperature environment. Therefore, the wide-mouth graphitization furnace provided by the embodiment of the present invention has the advantages of low cost and long service life.
[0032] Furthermore, a wide-mouth graphitization furnace provided by an embodiment of the present utility model has the furnace mouth of the furnace chamber (the inner cavity inlet and outlet of the furnace chamber, the cross-section of the entire furnace chamber) set in a flat shape, which is adapted to the fiber filaments to be graphitized, so that the effective space is large, further achieving energy conservation. Preferably, the shape of the induction coil section in the embodiment of the present utility model is set as a flat annular structure, which better meets the process requirements and can further reduce energy consumption.
[0033] Furthermore, an embodiment of the present utility model provides a wide-mouth graphitization furnace. The furnace chamber is made of graphite, and the thickness K of the furnace chamber and the highest design temperature T of the graphitization furnace satisfy the following relationship: when T < 2800 °C, K = 30 - 45 mm; when 2800 °C ≤ T ≤ 3200 °C, K = 0.2593 × e 0.0019×T ; where the unit of K is mm and the unit of T is °C. Here, through the optimized design of the thickness of the graphite furnace chamber, different furnace chamber thicknesses are used for different graphitization temperatures, economically and practically solving the problem that the wide-mouth furnace chamber is prone to fracture. Here, the design of the furnace chamber thickness collaborates with the above-mentioned structural design of the furnace chamber (such as the splicing design) to solve the problem of furnace chamber fracture of the wide-mouth graphitization furnace. Although the thicker the graphitization furnace chamber, the less likely it is to fracture and the higher its service life, the present utility model fully considers economic and other issues, and conducts collaborative optimization design on the furnace chamber structure and furnace chamber thickness to ensure economy and practicability.
[0034] Furthermore, an embodiment of the present utility model provides a wide-mouth graphitization furnace, wherein the wide-mouth graphitization furnace is an induction heating type graphitization furnace; by making the inner cavity of the furnace chamber include a plurality of sequentially continuous temperature sections, making the induction coil include a plurality of induction coil sections, the number of induction coil sections is the same as the number of temperature sections, and each induction coil section surrounds the corresponding temperature section to heat the corresponding temperature section; wherein, an electromagnetic shielding structure is arranged between any two adjacent induction coil sections to avoid the mutual influence between the magnetic induction lines of any two adjacent temperature sections. Through the above design, the continuous multi-temperature zone design of the induction heating type graphitization furnace is realized (so that the temperatures between the continuous temperature zones do not interfere with each other, realizing continuous multi-temperature zones), thereby meeting the requirements for large-scale and continuous preparation of polyacrylonitrile-based high-strength and high-modulus carbon fibers.
[0035] Furthermore, an embodiment of the present utility model provides a wide-mouth graphitization furnace, and the electromagnetic shielding structure is designed as follows: the electromagnetic shielding structure is formed by alternately stacking carbon fiber cloth and tungsten mesh in sequence. Preferably, the outer layers (the first layer and the last layer) of the electromagnetic shielding structure are both carbon fiber cloth. Through the above settings, the electromagnetic shielding structure has excellent electromagnetic shielding effects, can well isolate the mutual influence of adjacent induction coils, and ensure the stable operation of the equipment.
[0036] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the utility model in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Figure 1 It is a structural schematic diagram of a wide-mouth graphitization furnace provided in an embodiment of the utility model;
[0038] Figure 2 It is a cross-sectional schematic diagram of a wide-mouth graphitization furnace provided in an embodiment of the utility model;
[0039] Figure 3 It is a structural schematic diagram of a furnace section provided by an embodiment of the utility model;
[0040] Figure 4 It is a structural schematic diagram of an electromagnetic shielding structure provided by an embodiment of the utility model. DETAILED DESCRIPTION
[0041] In order to further explain the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the specific implementation methods, structures, features and effects of the utility model application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.
[0042] Example 1
[0043] This embodiment provides a wide-mouth graphitization furnace, wherein Figure 1 , Figure 2 and Figure 3 As shown, the wide-mouth graphitization furnace includes a furnace 2, and the furnace mouth width W of the furnace 2 is greater than 1m; wherein the furnace 2 is formed by sequentially splicing a plurality of furnace sections; wherein,
[0044] Each furnace section includes: a top plate 22, a bottom plate 23, a first arc-shaped side plate 24, and a second arc-shaped side plate 25; wherein the bottom plate 23 and the top plate 22 are arranged opposite to each other. The first side of the first arc-shaped side plate 24 is butted against the first side of the top plate 22, and the second side of the first arc-shaped side plate 24 is butted against the first side of the bottom plate 23. The first side of the second arc-shaped side plate 25 is butted against the second side of the top plate 22, and the second side of the second arc-shaped side plate 25 is butted against the second side of the bottom plate 23. The first side and the second side are two sides arranged opposite to each other.
[0045] Here, the wide-mouth graphitization furnace provided by this embodiment is designed such that the furnace chamber 2 is formed by sequentially splicing a plurality of furnace chamber segments. At the same time, the structure of each furnace chamber segment is designed to be formed by splicing a top plate 22, a bottom plate 23, a first arc-shaped side plate 24, and a second arc-shaped side plate 25. With this setting, on the one hand, for the selection of furnace chamber materials (graphite materials), large sizes are not required, thus reducing costs; on the other hand, the above structural design optimizes the stress-bearing situation of the furnace chamber, enabling it to withstand greater internal stress at the same span, thereby avoiding the problem that the furnace chamber is prone to fracture in a high-temperature environment. Therefore, this embodiment provides a wide-mouth graphitization furnace with a long lifespan and low cost.
[0046] Preferably, through the top plate 22, the bottom plate 23, the first arc-shaped side plate 24, and the second arc-shaped side plate 25, the cross-section of the furnace chamber segment forms a flat annular structure (for the term "flat annular structure" related to this utility model, refer to Figure 2 the shape of the inner cavity enclosed by the furnace chamber 2 in
[0047] Here, it should be noted that regarding the above-mentioned "butt joint" method, it can be achieved by any one of auxiliary clamping plates, screws, and post-bonding heat treatment. Preferably, it is the direct connection of auxiliary clamping plates and screws, so that the connection contact resistance is much smaller than the cross-sectional resistance.
[0048] Preferably, the auxiliary clamping plate method is designed as follows: The first side of the first arc-shaped side plate 24 is butt-jointed with the first side of the top plate 22 through a first connecting plate 26, and the second side of the first arc-shaped structure 24 is butt-jointed with the first side of the bottom plate 23 through a second connecting plate 27. The first side of the second arc-shaped side plate 25 is butt-jointed with the second side of the top plate 22 through a third connecting plate 28, and the second side of the second arc-shaped side plate 25 is butt-jointed with the second side of the bottom plate 23 through a fourth connecting plate 29.
[0049] Embodiment 2
[0050] Preferably, this embodiment provides a wide-mouth graphitization furnace. As Figures 1-3 shown, this embodiment is further designed as follows:
[0051] The material of the furnace chamber is graphite, preferably isostatic high-purity graphite.
[0052] Preferably, the thickness K of the furnace chamber and the design temperature T of the highest temperature zone of the graphitization furnace satisfy the following relationship:
[0053] When T < 2800 °C, K = 30 - 45 mm;
[0054] When 2800 °C ≤ T ≤ 3200 °C, K = 0.2593 × e 0.0019×T ;
[0055] wherein, the unit of K is mm and the unit of T is °C.
[0056] Herein, the above design objective is to ensure the service life of the furnace chamber and the structural strength of the furnace chamber on the premise of considering the economy such as the manufacturing cost of the furnace chamber; meanwhile, the design of the thickness of the furnace chamber can achieve the effect of secondary temperature equalization and ensure that the graphitization furnace has a small cross-sectional temperature difference.
[0057] Embodiment 3
[0058] Preferably, this embodiment provides a wide-mouth graphitization furnace, wherein, as shown in Figure 1 and Figure 2 , the wide-mouth graphitization furnace is an induction heating type graphitization furnace; wherein, the wide-mouth graphitization furnace further includes an induction coil 3. The inner cavity of the furnace chamber 2 includes a plurality of temperature sections that are successively continuous; the number of furnace chamber sections is the same as and corresponds one-to-one to the number of temperature sections. The induction coil 3 is arranged around the outer periphery of the furnace chamber 2 and is used to generate an induction current in the furnace chamber 2 to heat the furnace chamber 2. Among them, the induction coil 3 includes a plurality of induction coil sections; wherein, the number of induction coil sections is the same as the number of temperature sections (furnace chamber sections), and each induction coil section is arranged around its corresponding temperature section (furnace chamber section) to heat its corresponding temperature section; wherein, an electromagnetic shielding structure 4 is arranged between any two adjacent induction coil sections to avoid the mutual influence between the magnetic induction lines of any two adjacent temperature sections, so that the temperature of each temperature zone is independent.
[0059] It should be noted here that: on the one hand, the wide-mouth graphitization furnace provided in this embodiment is an induction heating type graphitization furnace, and there is no problem of "short service life of the graphite heating element" existing in the resistance type graphitization furnace. Therefore, compared with the existing resistance type graphitization furnace, the wide-mouth graphitization furnace in this embodiment has a long service life, low energy consumption, and a fast heating rate. On the other hand, in the existing induction graphitization furnace that generates eddy current heating by induction, the temperature zones are not continuous and there are cold zones between them. In this way, when graphitizing fibers, after passing through one temperature zone, first pass through the cold zone and then enter the next temperature zone, which is not conducive to the graphitization of fibers and simply cannot meet the requirements for the preparation of large-scale and continuous polyacrylonitrile-based high-strength and high-modulus carbon fibers. However, through the above settings in this embodiment, a continuous multi-temperature zone design of the induction heating type graphitization furnace is realized, that is, there are no cold zones between the temperature zones and the temperatures are independent, so as to meet the requirements for the preparation of large-scale and continuous polyacrylonitrile-based high-strength and high-modulus carbon fibers.
[0060] Among them, the inner cavity of the furnace chamber 2 has a wire threading channel 21, so that the fibers to be graphitized enter the inner cavity of the furnace chamber 2 from the inlet of the graphitization furnace, and after sequentially passing through multiple temperature zones continuously, they pass through the outlet of the graphitization furnace.
[0061] Preferably, the material of the electromagnetic shielding structure is selected as a set material; among them, in an inert atmosphere, the set material can withstand a temperature of ≥3000 °C.
[0062] Preferably, the number of temperature zones in this embodiment is greater than 1 and less than or equal to 9.
[0063] Embodiment 4
[0064] Preferably, this embodiment provides a wide-mouth graphitization furnace. Compared with the previous Embodiment 1, as Figure 1 、 Figure 2 and Figure 4 shown, this embodiment further makes the following designs:
[0065] The electromagnetic shielding structure 4 is formed by overlapping at least two layers of carbon fiber cloth. Or, as Figure 4 shown, the electromagnetic shielding structure 4 is formed by alternately overlapping the carbon fiber cloth 41 and the tungsten mesh 42 in sequence. Preferably, the outer layers (the first layer, the last layer) of the electromagnetic shielding structure 4 are both carbon fiber cloth. Here, through the above settings, not only can a better shielding effect be achieved, but also the ablation resistance of the electromagnetic shielding structure can be improved.
[0066] Through the above design, the electromagnetic shielding structure 4 has excellent electromagnetic shielding effect, can well isolate the mutual influence of adjacent induction coils, and ensure the stable operation of the equipment.
[0067] Embodiment 5
[0068] Preferably, this embodiment provides a wide-mouth graphitization furnace. Compared with the above embodiments, as Figure 1 、 Figure 2 shown, this embodiment further makes the following designs:
[0069] An insulating material 10 is filled between the furnace chamber 2 and the induction coil 3; preferably, the insulating material 10 is a high-temperature resistant graphite carbon felt, and when filling, an interleaved cross-section structure is adopted, which not only isolates the heat of the furnace chamber from spreading outwards, but also ensures that no induced current is generated inside it to cause self-heating problems.
[0070] The induction coil 3 is installed on the insulating skeleton 8 (specifically, an insulating material is wrapped outside the induction coil, and this material plays the role of insulation and skeleton); preferably, the material of the insulating skeleton 8 is refractory mortar. Soft magnetic materials are evenly distributed inside the insulating skeleton, playing a magnetic choking role.
[0071] The graphitization furnace includes a furnace shell 1. The furnace chamber 2 and the induction coil 3 are both located inside the furnace shell 1; heat insulation materials 7 are filled between the furnace shell 1, the furnace chamber 2, and the induction coil.
[0072] The graphitization furnace further includes: a controller 5 and a temperature measuring device 6; wherein, the number of the controller 5 and the temperature measuring device 6 is the same as the number of temperature zones, and they are in one-to-one correspondence; preferably, the temperature measuring device 6 is used to measure the temperature of the corresponding temperature zone; the controller 5 is connected to the corresponding temperature measuring device 6 and the induction coil section to control the temperature of the temperature zone respectively.
[0073] Preferably, detachable plugs 9 are provided at both the inlet and outlet of the graphitization furnace to prevent heat radiation. Specifically, plugs 9 are installed at both the inlet and outlet of the inner cavity of the furnace chamber, and through holes for the fiber filaments to pass through are provided on the plugs 9.
[0074] Preferably, the shape of the induction coil section is set to a flat annular structure, which better meets the process requirements and can further reduce energy consumption.
[0075] Preferably, an electromagnetic shielding structure 4 is also provided on the side of the first induction coil section close to the inlet of the graphitization furnace along the wire walking direction; an electromagnetic shielding structure 4 is also provided on the side of the last induction coil section close to the outlet of the graphitization furnace.
[0076] In summary, the graphitization furnace provided above has at least the following advantages:
[0077] (1) The spliced furnace chamber structure in the embodiment of the present invention can solve the problem that a wide-mouth over-temperature graphitization furnace cannot be manufactured due to material problems.
[0078] (2) The wide-mouth graphitization furnace of the present invention has a long service life. As a super-high temperature graphitization furnace (≥2800 °C) for long-term use, a multi-stage continuous heating intermediate frequency induction furnace. The stable operation time of the wide-mouth graphitization furnace of the present invention is long. When the graphitization temperature is below 2800 °C, the service life exceeds 2 years; when the graphitization temperature is 3200 °C, the service life exceeds 1 month.
[0079] (3) By adding an electromagnetic shielding plate, a design of multiple continuous temperature zones is realized, thus meeting the preparation requirements for large-scale and continuous polyacrylonitrile-based high-strength and high-modulus carbon fiber.
[0080] (4) There is no flat structure induction coil in the prior art. Compared with the conventional circular induction coil, the flat induction coil better meets the process requirements and can further reduce energy consumption.
[0081] (5) The wide-mouth graphitization furnace of the embodiment of the present utility model can also replace resistance furnaces in high-temperature application scenarios, such as low-temperature carbonization furnaces, high-temperature carbonization furnaces, ultra-high-temperature carbonization furnaces, etc., with a wide range of applications. It can be used for continuously preparing materials such as fibers under an inert atmosphere with gradient heating, such as carbon fibers, graphite fibers, silicon carbide fibers, etc. Compared with resistance furnaces, the wide-mouth graphitization furnace of the present utility model has the characteristics of high energy efficiency ratio, long service life, low cost, etc., and can operate stably at ultra-high temperature (≥2800 °C) for a long time.
[0082] The above are only the preferred embodiments of the present utility model, and do not impose any form of limitation on the present utility model. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present utility model still fall within the scope of the technical solution of the present utility model.
Claims
1. A wide-mouth graphitization furnace, characterized in that, The wide-mouth graphitization furnace includes a furnace chamber; wherein, the width W of the furnace mouth of the furnace chamber is greater than 1 m; wherein, the furnace chamber is formed by sequentially splicing a plurality of furnace chamber segments; wherein, each furnace chamber segment includes: a top plate; a bottom plate, the bottom plate and the top plate are arranged opposite to each other; a first arc-shaped side plate, a first side of the first arc-shaped side plate is butted against a first side of the top plate, and a second side of the first arc-shaped side plate is butted against a first side of the bottom plate; a second arc-shaped side plate, a first side of the second arc-shaped side plate is butted against a second side of the top plate, and a second side of the second arc-shaped side plate is butted against a second side of the bottom plate; wherein, the first side and the second side are two opposite sides.
2. The wide-mouth graphitization furnace according to claim 1, characterized in that, Through the top plate, the bottom plate, the first arc-shaped side plate and the second arc-shaped side plate, the cross-section of the furnace chamber segment forms a flat annular structure; and / or The shape of the furnace mouth of the furnace chamber is a flat annular opening.
3. The wide-mouth graphitization furnace according to claim 1, characterized in that, The first arc-shaped side plate is a U-shaped plate, and the second arc-shaped side plate is a U-shaped plate.
4. The wide-mouth graphitization furnace according to claim 1, wherein, The first side of the first arc-shaped side plate is butted against the first side of the top plate through a first connecting plate, and the second side of the first arc-shaped side plate is butted against the first side of the bottom plate through a second connecting plate; the first side of the second arc-shaped side plate is butted against the second side of the top plate through a third connecting plate, and the second side of the second arc-shaped side plate is butted against the second side of the bottom plate through a fourth connecting plate.
5. The wide-mouth graphitization furnace according to claim 1, characterized in that, The thickness K of the furnace chamber and the designed temperature T of the highest temperature zone of the graphitization furnace need to satisfy the following relationship: When T < 2800 °C, K = 30 - 45 mm; When 2800 °C ≤ T ≤ 3200 °C, K = 0.2593 × e 0.0019×T ; wherein, the unit of K is mm, and the unit of T is °C.
6. The wide-mouth graphitization furnace according to claim 1, characterized in that, The graphitization furnace is an induction heating type graphitization furnace; wherein, the inner cavity of the furnace chamber includes a plurality of temperature zones that are continuously arranged in sequence; wherein, the number of the furnace chamber segments is the same as and corresponds one-to-one to the number of the temperature zones; The wide-mouth graphitization furnace further includes an induction coil; wherein, the induction coil is arranged around the outer periphery of the furnace chamber and is used for generating an induced current in the furnace chamber to heat the furnace chamber; wherein, the induction coil includes a plurality of induction coil segments; wherein, the number of the induction coil segments is the same as the number of the temperature zones, and each induction coil segment is arranged around its corresponding temperature zone to heat its corresponding temperature zone; wherein, an electromagnetic shielding structure is arranged between any two adjacent induction coil segments to avoid mutual influence between the magnetic induction lines of any two adjacent temperature zones.
7. The wide-mouth graphitization furnace according to claim 6, wherein, The inner cavity of the furnace chamber has a wire threading channel to enable the fibers to be graphitized to sequentially pass through a plurality of temperature zones continuously.
8. The wide-mouth graphitization furnace according to claim 6, characterized in that, The material of the electromagnetic shielding structure is selected as a set material; wherein, in an inert atmosphere, the set material can withstand a temperature of ≥ 3000 °C.
9. The wide-mouth graphitization furnace according to claim 6, wherein, The electromagnetic shielding structure is formed by overlapping at least two layers of carbon fiber cloth; or The electromagnetic shielding structure is formed by alternately overlapping carbon fiber cloth and tungsten mesh in sequence, wherein the outer layers of the electromagnetic shielding structure are all carbon fiber cloth.
10. The wide-mouth graphitization furnace according to claim 6, characterized in that, The electromagnetic shielding structure is an electromagnetic shielding plate; and / or An electromagnetic shielding structure is arranged between any two adjacent furnace chamber segments; through holes for the fibers to pass through are formed in the electromagnetic shielding structure; and / or The induction coil section is wound around the outer periphery of the furnace chamber; wherein, the induction coil section has a flat ring structure; and / or The material of the furnace chamber is graphite; and / or The number of the temperature sections is greater than 1 and less than or equal to 9.
11. The wide-mouth graphitization furnace according to claim 6, characterized in that, Heat insulation material is filled between the furnace chamber and the induction coil.
12. The wide-mouth graphitization furnace according to claim 11, characterized in that, The heat insulation material is high-temperature resistant graphite carbon felt.
13. The wide-mouth graphitization furnace according to claim 6, characterized in that, The induction coil is installed on an insulating skeleton.
14. The wide-mouth graphitization furnace according to claim 13, characterized in that, The material of the insulating skeleton is refractory mortar.
15. The wide-mouth graphitization furnace according to claim 13, characterized in that, Soft magnetic materials are evenly distributed inside the insulating skeleton to play a magnetic choking effect.
16. The wide-mouth graphitization furnace according to claim 6, wherein The graphitization furnace includes a furnace shell; the furnace chamber and the induction coil are both located inside the furnace shell; the gaps between the furnace shell and the furnace chamber and the induction coil are filled with heat preservation materials.
17. The wide-mouth graphitization furnace according to claim 6, characterized in that, The graphitization furnace further includes: a controller and a temperature measuring device; wherein, the numbers of the controller and the temperature measuring device are the same as the number of the temperature sections, and they are in one-to-one correspondence.
18. The wide-mouth graphitization furnace according to claim 17, wherein, The temperature measuring device is used to measure the temperature of the corresponding temperature section; the controller is connected to the corresponding temperature measuring device and the induction coil section.
19. The mouth-type graphitization furnace according to claim 6, characterized in that, Detachable plugs are provided at both the inlet and the outlet of the graphitization furnace to prevent heat radiation; and / or Along the wire running direction, an electromagnetic shielding structure is also provided on one side of the first induction coil section close to the inlet of the graphitization furnace; an electromagnetic shielding structure is also provided on one side of the last induction coil section close to the outlet of the graphitization furnace.