A carbonization furnace mouth sealing structure for carbon fiber production

Abstract

The present invention discloses a carbonization furnace mouth sealing structure for carbon fiber production, including a duckbill furnace mouth, a rotating air cavity, a furnace atmosphere monitoring system and a furnace bar. The duckbill furnace mouth is composed of a furnace mouth section, an expansion section and a furnace body connecting section. Rotating air cavities are arranged above and below the furnace mouth section. The rotating air cavity is used to supply nitrogen to the furnace, and the amount of nitrogen can be adjusted and controlled; the long hole on the rotating air cavity is used to release gas, and the air cavity can rotate to achieve the purpose of adjusting the outlet angle; the furnace atmosphere monitoring system sends the gas collected from the sampling port to an online oxygen analyzer and an online dew point meter for real-time monitoring through a filter and a micro air pump, and adjusts the nitrogen gas volume and the air intake angle according to the real-time monitoring data to meet the sealing requirements. The carbonization furnace mouth effectively solves the problem of carbonization furnace mouth sealing and nitrogen direct blowing causing disturbance to the fiber, so that the carbon fiber runs smoothly during the carbonization process, can isolate air reaction, and can prevent hair and performance degradation caused by nitrogen direct blowing.

Description

Technical Field

[0001] The invention relates to the technical field of carbonization furnaces, in particular to a carbonization furnace mouth sealing structure for carbon fiber production. Background Art

[0002] In the process of manufacturing carbon fiber, the carbonization process is a complex process of physical and chemical changes and structural transformation. It is a process of thermal decomposition and thermal polycondensation under the protection of inert gas. As a result, the trapezoidal structure of the pre-oxidized filaments is transformed into the chaotic layer graphite structure of carbon fiber. The carbonization process is a key process in the preparation of carbon fiber. The low-temperature carbonization furnace and the high-temperature carbonization furnace are the key equipment for the preparation of carbon fiber. The core technology is the wide-caliber carbonization furnace and its supporting sealing structure. First, a slight positive pressure is formed in the carbonization furnace to prevent the outside air from entering the furnace and destroying the inert gas environment. Second, the fibers are purged to prevent oxygen and water vapor in the running filament bundle from entering the carbonization furnace. These two points are the top priorities in the production of carbon fiber.

[0003] At present, most of the traditional carbonization furnace sealing technologies adopt non-contact labyrinth sealing and flat plate direct blowing. The non-contact labyrinth sealing uses a partition to form a gas expansion chamber. The nitrogen enters the expansion chamber and encounters the partition to form turbulence, forming a purge on the fiber, replacing the air entrained in the fiber, and preventing the air from entering the carbonization furnace. However, in actual application, the size and direction of the gas turbulence formed in the expansion chamber are difficult to control, which is greatly affected by the processing accuracy of the equipment and the amount of nitrogen, so it is difficult to achieve the expected effect. The flat plate direct blowing sealing technology has a simple structure and is easy to process, but it uses a large amount of nitrogen, and the direct blowing of the fiber can easily cause the fiber to become fuzzy and the overall running tow to shake. Once the gas volume is reduced, the problem of poor sealing effect will appear.

[0004] Under high temperature conditions, oxygen and water vapor will corrode the metal muffle or graphite muffle of the carbonization furnace, reducing the service life of the carbonization furnace, and oxidize the carbon fiber in the carbonization process under high temperature conditions, which will reduce the various performance indicators of the carbon fiber and make it impossible to produce high-performance carbon fiber. Therefore, it is necessary to design a new sealing design that can completely solve the above problems, greatly extend the service life of the carbonization furnace, and improve the performance indicators of the carbon fiber. Summary of the invention

[0005] The purpose of the present invention is to provide a carbonization furnace mouth sealing structure for carbon fiber production, which effectively solves the problem of carbonization furnace mouth sealing and nitrogen direct blowing causing disturbance to the fiber, so that the carbon fiber can run smoothly during the carbonization process, isolating the air reaction and preventing the hair and performance degradation caused by nitrogen direct blowing.

[0006] To achieve the above object, the present invention provides the following solution: The present invention provides a carbonization furnace mouth sealing structure for carbon fiber production, comprising:

[0007] A duckbill furnace mouth, the duckbill furnace mouth comprising a furnace mouth section, an expansion section and a furnace body connecting section connected in sequence, the furnace body connecting section being sealed and mounted on the furnace body; and

[0008] Rotating air cavities, wherein a plurality of rotating air cavities are symmetrically arranged above and below the furnace mouth section, wherein the rotating air cavities include a cylindrical shell and the air cavities, wherein the cylindrical shell is rotatably mounted on the furnace mouth section, a long hole is opened on the cylinder along the axial direction, the air cavities are connected to a nitrogen source, and the nitrogen flow rate of each air cavity is adjustable; and

[0009] A furnace atmosphere monitoring system, the furnace atmosphere monitoring system comprising a sampling port, a filter, a trace air pump, an online oxygen analyzer and an online dew point meter, the expansion section is provided with a plurality of sampling ports according to the fiber running width, and the gas collected at the sampling port is sent to the online oxygen analyzer and the online dew point meter through the filter and the trace air pump for real-time monitoring; and

[0010] A grate bar is installed at the entrance of the furnace mouth section.

[0011] Preferably, the duckbill furnace mouth is welded with high temperature resistant stainless steel plates, and the furnace mouth section, expansion section and furnace body connecting section connected in sequence form a duckbill shape, and the furnace body connecting section is installed on the furnace body through a flange.

[0012] Preferably, the rotating air cavity uses stainless steel as a cylindrical cavity, that is, the cylindrical shell is made of stainless steel, and a nitrogen interface is provided at the end of the cylindrical shell. The nitrogen interface is connected to a nitrogen source and supplies nitrogen to the air cavity.

[0013] Preferably, a rotor volume flow meter is provided on the pipeline connecting the nitrogen interface and the nitrogen source, and the rotor volume flow meter is used to adjust and control the amount of nitrogen in each rotating air cavity.

[0014] Preferably, the rotation range of the cylindrical shell in the furnace mouth section is 60°, and the long hole changes direction as the cylindrical shell rotates.

[0015] Preferably, the grate bar is made of aluminum alloy, and the wire width of the grate bar is rounded and smoothed at the top and bottom.

[0016] Preferably, the position of the grate bar can be adjusted up and down to achieve a suitable opening.

[0017] Compared with the prior art, the present invention has achieved the following beneficial technical effects:

[0018] The carbonization furnace mouth sealing structure for carbon fiber production in the present invention includes a duckbill furnace mouth, a rotating air cavity, a furnace atmosphere monitoring system and a furnace bar. The duckbill furnace mouth is composed of a furnace mouth section, an expansion section and a furnace body connecting section to form a duckbill. Rotating air cavities are arranged above and below the furnace mouth section. The rotating air cavity is used to supply nitrogen to the furnace, and the amount of nitrogen can be adjusted and controlled; the long hole on the rotating air cavity is used to release gas, and the air cavity can rotate to achieve the purpose of adjusting the outlet angle; the furnace atmosphere monitoring system sends the gas collected from the sampling port to the online oxygen analyzer and the online dew point meter for real-time monitoring through a filter and a micro air pump, and adjusts the nitrogen gas volume and the air intake angle according to the real-time monitoring data to meet the sealing requirements. The carbonization furnace mouth effectively solves the problem of carbonization furnace mouth sealing and nitrogen direct blowing causing disturbance to the fiber, so that the carbon fiber runs smoothly during the carbonization process, which can isolate air reaction and prevent hair and performance degradation caused by nitrogen direct blowing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a side view of the sealing structure of the furnace mouth of the carbonization furnace for producing carbon fiber in an embodiment of the present invention;

[0021] Figure 2 for Figure 1 A top view of

[0022] Figure 3 It is the structural diagram of the rotating air cavity;

[0023] Figure 4 is a schematic diagram of the rotation angle of the rotating air cavity;

[0024] Figure 5 for Figure 3 DD section view;

[0025] Figure 6 This is a schematic diagram of the furnace atmosphere monitoring system;

[0026] Figure 7 It is the structural schematic diagram of the grate bar;

[0027] Among them, 1. grate bar; 2. furnace mouth section; 3. cylindrical shell; 4. rotating air cavity; 5. expansion section; 6. furnace body connection section; 7. long hole; 8. nitrogen interface; 9. sampling port; 10. filter; 11. trace air pump; 12. online oxygen analyzer; 13. online dew point meter. DETAILED DESCRIPTION

[0028] 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.

[0029] The purpose of the present invention is to provide a carbonization furnace mouth sealing structure for carbon fiber production, which effectively solves the problem of carbonization furnace mouth sealing and nitrogen direct blowing causing disturbance to the fiber, so that the carbon fiber can run smoothly during the carbonization process, isolating the air reaction and preventing the hair and performance degradation caused by nitrogen direct blowing.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] like Figure 1-Figure 7 As shown, the present invention provides a carbonization furnace mouth sealing structure for carbon fiber production, comprising

[0032] A duckbill furnace mouth, the duckbill furnace mouth comprises a furnace mouth section 2, an expansion section 5 and a furnace body connecting section 6 which are connected in sequence, and the furnace body connecting section 6 is sealed and installed on the furnace body; and

[0033] Rotating air cavity 4, multiple groups of rotating air cavity 4 are symmetrically arranged above and below the furnace mouth section 2, the rotating air cavity 4 comprises a cylindrical shell 3 and an air cavity, the cylindrical shell 3 is rotatably mounted on the furnace mouth section 2, a long hole 7 is opened on the cylinder along the axial direction, the air cavity is connected to the nitrogen source, and the nitrogen flow rate of each air cavity is adjustable; and

[0034] The furnace atmosphere monitoring system includes a sampling port 9, a filter 10, a trace air pump 11, an online oxygen analyzer 12 and an online dew point meter 13. The expansion section 5 is provided with a plurality of sampling ports 9 according to the fiber running width. The gas collected at the sampling port 9 is sent to the online oxygen analyzer 12 and the online dew point meter 13 through the filter 10 and the trace air pump 11 for real-time monitoring; and

[0035] Grate bar 1: A grate bar 1 is installed at the entrance of the furnace mouth section 2.

[0036] In one embodiment, the duckbill furnace mouth is welded with high temperature resistant stainless steel plates, and three groups of rotating air cavities 4 are arranged above and below the furnace mouth section 2 to supply nitrogen into the furnace. The furnace mouth section 2, the expansion section 5 and the furnace body connecting section 6 connected in sequence form a duckbill shape, and the furnace body connecting section 6 is installed on the furnace body through a flange.

[0037] In one embodiment, the rotating air cavity 4 is made of stainless steel as a cylindrical cavity, a series of long holes 7 are opened on the long side of the cylinder for gas discharge, and a nitrogen interface 8 is made at the round end of the cylinder for gas intake, which is inserted into the cylindrical shell 3 reserved for the duckbill furnace mouth. The air cavity can rotate within a range of 60° to achieve the purpose of adjusting the gas discharge angle. That is, the cylindrical shell 3 is made of stainless steel, and a nitrogen interface 8 is provided at the end of the cylindrical shell 3, which is connected to the nitrogen source and supplies nitrogen to the air cavity.

[0038] In one of the embodiments, a rotor volume flow meter is provided on the pipeline connecting the nitrogen interface 8 with the nitrogen source, and the rotor volume flow meter is used to adjust and control the amount of nitrogen in each rotating air cavity 4.

[0039] In one embodiment, the rotation range of the cylindrical shell 3 in the furnace mouth section 2 is 60°, and the long hole 7 changes direction with the rotation of the cylindrical shell 3. Three sampling ports 9 are set in the furnace mouth expansion section 5 according to the fiber running width, and the gas collected in the furnace is sent to the online oxygen analyzer 12 and the online dew point meter 13 through the filter 10 and the trace air pump 11 for real-time monitoring. According to the real-time monitoring data, the corresponding controller in the furnace body adjusts the nitrogen gas volume by adjusting the rotor volume flowmeter, and at the same time adjusts the air inlet angle at the long hole 7 of the rotating air cavity 4 to meet the sealing requirements.

[0040] In one embodiment, the grate bar 1 is made of aluminum alloy, and is rounded and smoothed above and below the wire width to avoid wire damage.

[0041] The control technology method of the sealed form is to adjust the rotating air cavity 4 to the vertical fiber outlet in advance, and adjust the nitrogen flow rate so that air does not enter the carbonization furnace. After the fiber is running in the carbonization furnace, turn on the furnace atmosphere monitoring system, adjust the flow rate of the online oxygen analyzer 12 and the online dew point meter 13 to the required flow rate of the instrument, purge according to the instrument requirements, and then start the test. After the detected value is stable, first adjust the nitrogen flow rate, and then adjust the outlet angle of the rotating air cavity 4, control the carbonization furnace inlet dew point at ≤-70℃, the oxygen content at ≤10ppm, the carbonization furnace outlet dew point at ≤-80℃, and the oxygen content at ≤5ppm. If these two sets of numerical requirements are met, it is considered to be adjusted in place.

[0042] Embodiment 1

[0043] The oxidized pre-oxidized wire enters the furnace through the grate bar 1. The grate bar 1 can be adjusted up and down. After reaching the appropriate opening, the bolts are tightened to fix the grate bar 1. After the nitrogen flow regulation system quantitatively adjusts each nitrogen, the nitrogen is sent to the rotating air cavity 4 through the nitrogen interface 8, and the micro air pump 11 is turned on to perform online detection of the gas in the furnace. According to the values ​​displayed by the online oxygen analyzer 12 and the online dew point meter 13, the purge angle and nitrogen flow rate of the rotating air cavity 4 are adjusted to prevent the fiber from shaking. The dew point at the inlet of the carbonization furnace is controlled at ≤-70℃, the oxygen content is controlled at ≤10ppm, and the dew point at the outlet of the carbonization furnace is controlled at ≤-80℃, and the oxygen content is controlled at ≤5ppm as the benchmark for qualified monitoring data.

[0044] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0045] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A carbonization furnace mouth sealing structure for carbon fiber production, characterized in that: include A duckbill furnace mouth, the duckbill furnace mouth comprising a furnace mouth section, an expansion section and a furnace body connecting section connected in sequence, the furnace body connecting section being sealed and mounted on the furnace body; and Rotating air cavities, wherein a plurality of rotating air cavities are symmetrically arranged above and below the furnace mouth section, wherein the rotating air cavities include a cylindrical shell and an air cavity, wherein the cylindrical shell is rotatably mounted on the furnace mouth section, and a long hole is opened on the cylindrical shell along the axial direction, wherein the air cavity is connected to a nitrogen source, and the nitrogen flow rate of each air cavity is adjustable; and A furnace atmosphere monitoring system, the furnace atmosphere monitoring system comprising a sampling port, a filter, a trace air pump, an online oxygen analyzer and an online dew point meter, the expansion section is provided with a plurality of sampling ports according to the fiber running width, and the gas collected at the sampling port is sent to the online oxygen analyzer and the online dew point meter through the filter and the trace air pump for real-time monitoring; as well as A grate bar is installed at the entrance of the furnace mouth section.

2. The carbonization furnace mouth sealing structure for carbon fiber production according to claim 1, characterized in that: The duckbill furnace mouth is welded with stainless steel plates, and the furnace mouth section, expansion section and furnace body connecting section connected in sequence form a duckbill shape, and the furnace body connecting section is installed on the furnace body through a flange.

3. The carbonization furnace mouth sealing structure for carbon fiber production according to claim 1, characterized in that: The rotating air cavity is made of stainless steel as a cylindrical cavity, that is, the cylindrical shell is made of stainless steel, and a nitrogen interface is provided at the end of the cylindrical shell. The nitrogen interface is connected to a nitrogen source and supplies nitrogen to the air cavity.

4. The carbonization furnace mouth sealing structure for carbon fiber production according to claim 3, characterized in that: A rotor volume flow meter is provided on the pipeline connecting the nitrogen interface and the nitrogen source, and the rotor volume flow meter is used to adjust and control the amount of nitrogen in each rotating air cavity.

5. The carbonization furnace mouth sealing structure for carbon fiber production according to claim 1, characterized in that: The rotation range of the cylindrical shell in the furnace mouth section is 60°, and the long hole changes direction as the cylindrical shell rotates.

6. The carbonization furnace mouth sealing structure for carbon fiber production according to claim 1, characterized in that: The grate bar is made of aluminum alloy, and the wire width of the grate bar is rounded and smoothed at the top and bottom.

7. The carbonization furnace mouth sealing structure for carbon fiber production according to claim 1, characterized in that: The position of the grate bar can be adjusted up and down.

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