Gas cooling tank and carbon fiber production system

Abstract

The utility model provides a gas cooling tank and a carbon fiber production system, a partition plate is arranged in the gas cooling tank, an inner cavity of the gas cooling tank is divided into an upper cavity and a lower cavity by the partition plate, the upper cavity is provided with a liquid inlet and a gas outlet, the lower cavity is provided with a gas inlet and a gas outlet, and the liquid inlet and the gas outlet are communicated with each other. A liquid outlet is formed in the bottom of the lower chamber; at least one heat exchange pipe is further vertically arranged in the gas cooling tank, an opening in the upper end of the heat exchange pipe is communicated with the upper cavity, an inner cavity of the heat exchange pipe is separated from the lower cavity, the liquid inlet is used for being filled with liquid nitrogen, and the gas inlet is used for being filled with gas to be cooled; the cooling capacity generated by liquid nitrogen vaporization in the carbon fiber production process is used for cooling and collecting the to-be-cooled gas, energy is saved, and cost is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of carbon fiber production, and in particular relates to a gas cooling tank and a carbon fiber production system. Background Art

[0002] The production process of polyacrylonitrile carbon fiber includes polymerization section and spinning section. A lot of waste gas (tail gas) will be generated in the polymerization section and spinning section. The main components of the waste gas are acrylonitrile, dimethyl sulfoxide and its decomposition products. Because the temperature of each section in the preparation process of polyacrylonitrile fiber is different, the amount of dimethyl sulfoxide decomposition in each section will also be different. In addition, methyl mercaptan, methyl sulfide and other substances in the waste gas decomposed by dimethyl sulfoxide have a strong odor, which has the most serious impact on the atmosphere. In recent years, the control of volatile organic compounds has developed rapidly, and the main control technologies include adsorption technology, plasma technology, and regenerative thermal incinerator incineration technology.

[0003] In the process of carbon fiber production, liquid nitrogen gasification is used for atmosphere protection of low and high carbonization furnaces in the carbonization section. High-purity liquid nitrogen flows through the gasifier through the pressure in the tank, is connected through the vacuum sleeve, and then supplied to the carbonization workshop by decompression. In the prior art, the cold energy generated by the liquid nitrogen vaporization process is not well utilized, resulting in a certain waste of resources.

[0004] How to use the cold energy generated by the vaporization of liquid nitrogen to collect part of the waste gas in the carbon fiber production process is a technical problem that needs to be solved at present. Utility Model Content

[0005] Therefore, the utility model provides a gas cooling tank and a carbon fiber production system, which can utilize the cold energy generated by the vaporization of liquid nitrogen during the carbon fiber production process to cool and collect the waste gas generated by the carbon fiber production system, thereby saving energy and reducing costs.

[0006] On the one hand, the utility model provides a gas cooling tank, wherein a partition is arranged inside the gas cooling tank, wherein the partition divides the inner cavity of the gas cooling tank into an upper chamber and a lower chamber, wherein the upper chamber is provided with a liquid inlet and a gas outlet, wherein the lower chamber is provided with a gas inlet and a gas outlet, and wherein a liquid discharge port is arranged at the bottom of the lower chamber; wherein the liquid inlet is used for filling with liquid nitrogen, and the gas inlet is used for filling with gas to be cooled;

[0007] At least one heat exchange tube is vertically arranged in the gas cooling tank, the upper end opening of the heat exchange tube is connected to the upper chamber, and the lower end of the heat exchange tube is located in the lower chamber; the inner cavity of the heat exchange tube is isolated from the lower chamber.

[0008] In some embodiments, a plurality of baffles are laterally arranged in the lower chamber, and a tortuous channel is formed between the plurality of baffles; the gas to be cooled entering the lower chamber from the gas inlet flows through the tortuous channel; and at least one of the heat exchange tubes passes through the tortuous channel.

[0009] In some embodiments, a plurality of baffles are laterally fixed on the inner wall of the gas cooling tank in sequence from top to bottom, an airflow channel is formed between two adjacent baffles, at least one heat exchange tube passes through at least one of the airflow channels; two adjacent airflow channels are connected via a vertical channel; from top to bottom, the projections of two adjacent vertical channels from top to bottom do not overlap; the tortuous channel includes an airflow channel and the vertical channel.

[0010] In some embodiments, a gap is formed between the top baffle and the partition, the vertical channel is provided between the top baffle and the inner wall surface of the gas cooling tank, and the gas inlet leads to the gap.

[0011] In some embodiments, a liquid level gauge is provided on the gas cooling tank, and the liquid level gauge is used to monitor the liquid level of liquid nitrogen in the upper chamber.

[0012] In some embodiments, there are multiple heat exchange tubes, and the lower end opening of each heat exchange tube is closed.

[0013] In some embodiments, there are multiple heat exchange tubes, and the lower end openings of at least two of the heat exchange tubes are connected to each other.

[0014] In some embodiments, a box body is disposed in the lower chamber, and lower end openings of at least two of the heat exchange tubes are connected to the inner cavity of the box body.

[0015] On the other hand, the utility model also provides a carbon fiber production system, including a liquid nitrogen storage tank, a carbonization furnace, a polymerization section, a spinning section and the gas cooling tank; the outlet of the liquid nitrogen storage tank is connected to the liquid inlet, and the gas outlet is connected to the protective gas inlet of the carbonization furnace; the gas to be cooled is the exhaust gas generated by the polymerization section and the spinning section.

[0016] In some embodiments, the carbon fiber production system further includes a liquid nitrogen vaporization device, and the outlet of the liquid nitrogen storage tank is further connected to the inlet of the liquid nitrogen vaporization device.

[0017] Liquid nitrogen enters the upper chamber through the liquid inlet, and flows downward into the heat exchange tube under the action of gravity. The gas to be cooled (tail gas) enters the lower chamber through the gas inlet. The liquid nitrogen vaporizes to generate cold to cool the gas to be cooled. The gas to be cooled is discharged from the liquid outlet after being cooled into liquid, and the gas to be cooled that has not been cooled into liquid is discharged from the gas outlet; the liquid nitrogen cools the gas to be cooled through the heat exchange tube, and the corresponding liquid nitrogen absorbs heat and vaporizes. The vaporized nitrogen flows upward out of the heat exchange tube in the heat exchange tube and enters the upper chamber. The vaporized nitrogen is discharged from the gas cooling tank through the exhaust port and flows into the carbonization furnace as a protective gas. The utility model cleverly utilizes the heat exchange tube and the upper chamber above the heat exchange tube. The liquid nitrogen cools the gas to be cooled while vaporizing, which not only realizes the vaporization of liquid nitrogen, but also realizes the cooling and collection of the gas to be cooled, improves the comprehensive utilization of liquid nitrogen, and reduces energy consumption.

[0018] The utility model also arranges a plurality of baffles in the lower chamber, and the plurality of baffles make the flow path of the gas to be cooled in the lower chamber tortuous, change the flow direction and speed of the gas to be cooled, make the gas to be cooled form a turbulent state in the gas cooling tank, improve the heat exchange effect between the gas to be cooled and the liquid nitrogen, and improve the cooling efficiency of the gas to be cooled. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the implementation or the prior art description. The drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0020] Figure 1 It is a schematic diagram of a carbon fiber production system according to an embodiment of the utility model;

[0021] Figure 2 This is a schematic diagram of the appearance of a cooling tank according to an embodiment of the utility model;

[0022] Figure 3 This is a cross-sectional view of the cooling tank when the box body is provided in the embodiment of the utility model;

[0023] Figure 4 It is a cross-sectional view of the cooling tank when the lower ends of the heat exchange tubes in the embodiment of the utility model are all closed;

[0024] Figure 5 This utility model embodiment Figure 3 AA section view.

[0025] The accompanying drawings are marked as follows:

[0026] 1. Gas cooling tank; 101. Upper chamber; 102. Lower chamber; 103. Partition; 104. Top cover; 201. Liquid inlet; 2011. Liquid inlet pipe; 202. Gas outlet; 301. Gas inlet; 302. Gas outlet; 4. Liquid discharge port; 5. Heat exchange tube; 6. Baffle; 601. Air flow channel; 602. Vertical channel; 603. Partition; 701. Liquid level meter; 702. Control valve; 703. Box body; 801. Liquid nitrogen storage tank; 802. Carbonization furnace; 803. Liquid nitrogen vaporization device; 804. Recovery tank. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the utility model and its application or use. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0028] In the description of the present utility model, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present utility model; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0029] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0030] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the utility model.

[0031] In the process of engineering preparation of polyacrylonitrile carbon fiber, waste gas will inevitably be generated. These waste gases can be effectively recycled through organized collection to minimize unorganized emissions. By analyzing the process of carbon fiber preparation and the mechanism of waste gas generation, the source of waste gas generation in the wet spinning or dry-jet wet spinning of PAN-based carbon fiber using dimethyl sulfoxide as solvent is basically determined. The carbon fiber preparation section can be divided into polymerization section, spinning section, and carbonization section. The three sections have certain differences in the waste gas generated due to the differences in their production processes. In the process of carbon fiber production, acrylonitrile, dimethyl sulfoxide and their decomposition products will be produced in the polymerization section and spinning section; and in the carbonization section, small molecules such as hydrogen cyanide and ammonia will be produced due to the cyclization reaction of acrylonitrile structural units in the fiber.

[0032] The main components of the original fiber waste gas are acrylonitrile, dimethyl sulfoxide and its decomposition products. Because the temperature of each section in the preparation process of polyacrylonitrile fiber is different, the amount of dimethyl sulfoxide decomposition in each section will also be different. In addition, the substances such as methyl mercaptan and methyl sulfide in the decomposition waste gas of dimethyl sulfoxide have a strong odor, which has the most serious impact on the atmosphere. In recent years, the treatment of volatile organic compounds has been rapidly developed. The main treatment technologies include adsorption technology, plasma technology, and regenerative thermal incinerator incineration technology. They all have their own advantages and disadvantages and use occasions. It is necessary to explore a new type of original fiber waste gas treatment device through the original fiber waste gas treatment technology. In the process of carbon fiber production, liquid nitrogen gasification is used for the atmosphere protection of the low and high carbonization furnaces in the carbonization section. The high-purity liquid nitrogen flows through the gasifier through the pressure in the tank, is connected through the vacuum sleeve, and then supplied to the carbonization workshop by decompression. However, the cold source of the liquid nitrogen gasification has not been well utilized, resulting in great waste. Based on the fact that liquid nitrogen absorbs a lot of heat and releases cold when vaporizing, the utility model provides a carbon fiber production system, which utilizes nitrogen vaporization to condense waste gas, thereby solving the technical problem in the prior art that it consumes a lot of energy to recover waste gas during carbon fiber production.

[0033] The description of this application is based on the overall position of the cooling tank during normal use as an example. Figure 3 As shown, the cooling tank is vertically arranged as an example for explanation.

[0034] See also Figure 1-5A gas cooling tank, wherein a partition 103 is provided in the gas cooling tank 1, and the partition 103 divides the inner cavity of the gas cooling tank 1 into an upper chamber 101 and a lower chamber 102, the upper chamber 101 is provided with a liquid inlet 201 and a gas outlet 202, the lower chamber 102 is provided with a gas inlet 301 and a gas outlet 302, and the bottom of the lower chamber 102 is provided with a drain port 4; the liquid inlet 201 is used for filling liquid nitrogen, and the gas inlet 301 is used for filling the gas to be cooled;

[0035] At least one heat exchange tube 5 is vertically arranged in the gas cooling tank 1. The upper end opening of the heat exchange tube 5 is connected to the upper chamber 101, and the lower end of the heat exchange tube 5 is located in the lower chamber 102; the inner cavity of the heat exchange tube 5 is isolated from the lower chamber 102.

[0036] When the gas cooling tank 1 is used for carbon fiber production, the gas to be cooled is the tail gas generated by the polymerization section and the spinning section.

[0037] The tail gas (gas to be cooled) generated by the polymerization section and the spinning section in the carbon fiber production process enters the lower chamber 102 through the gas inlet 301, and the liquid nitrogen enters the upper chamber 101 from the liquid inlet 201. The liquid nitrogen flows downward into the heat exchange tube 5 while flowing flat in the upper chamber 101. Part of the liquid nitrogen vaporizes in the upper chamber 101, and the vaporized nitrogen is discharged from the gas outlet 202. Part of the liquid nitrogen flows into the heat exchange tube 5 and exchanges heat with the tail gas through the heat exchange tube 5. During the heat exchange process, part of the tail gas is cooled to liquid and flows downward, and finally flows out from the liquid discharge port 4; the tail gas that is not cooled to liquid is discharged from the gas outlet 302. If the gas discharged from the gas outlet 302 meets the regulations, it can be directly discharged into the atmosphere; the liquid nitrogen absorbs heat from the tail gas and vaporizes into nitrogen. Under the action of buoyancy, the nitrogen flows upward along the heat exchange tube 5 into the upper chamber 101 and is discharged from the gas outlet 202. Through the above process, the liquid nitrogen is vaporized and is convenient to enter the carbonization furnace 802 as a protective gas. At the same time, part of the tail gas is cooled into a liquid state and discharged from the drain port 4 for collection. The vaporization of liquid nitrogen in the gas cooling tank 1 is conducive to reducing the workload of the special nitrogen vaporization device, and is conducive to reducing the volume of the special nitrogen vaporization device, thereby reducing the footprint of the nitrogen vaporization device; the tail gas is cooled into a liquid state in the gas cooling tank 1 using the cold energy generated by nitrogen vaporization, and then collected, saving energy.

[0038] Preferably, a plurality of baffles 6 are transversely arranged in the lower chamber 102, and a tortuous channel is formed between the plurality of baffles 6; the gas to be cooled entering the lower chamber 102 from the gas inlet 301 passes through the tortuous channel; and at least one heat exchange tube 5 passes through the tortuous channel.

[0039] The gas to be cooled is gradually cooled while flowing through the tortuous channel. Part of the gas to be cooled is cooled into liquid state, flows downward under the action of gravity, and is finally discharged from the drain port 4 and collected; part of the gas to be cooled is not cooled into liquid state after flowing through the tortuous channel, and the gas to be cooled that is not cooled into liquid state is discharged from the gas outlet 302. The tortuous channel increases the flow path of the gas to be cooled, which is conducive to sufficient heat exchange between the gas to be cooled and the heat exchange tube 5.

[0040] Preferably, Figure 3 As shown, a plurality of baffles 6 are laterally fixed on the inner wall of the gas cooling tank 1 in sequence from top to bottom, an airflow channel 601 is formed between two adjacent baffles 6, at least one heat exchange tube 5 passes through at least one of the airflow channels 601; two adjacent airflow channels 601 are connected via a vertical channel 602; from top to bottom, the projections of two adjacent vertical channels 602 from top to bottom do not overlap; the tortuous channel includes the airflow channel 601 and the vertical channel 602.

[0041] The utility model provides a plurality of baffles 6 in the lower chamber 102, and the plurality of baffles 6 are laterally fixed on the inner wall of the gas cooling tank 1 in sequence from top to bottom, and an airflow channel 601 is formed between two adjacent baffles 6, and the heat exchange tube 5 passes through the airflow channel 601; the two adjacent airflow channels 601 are connected via a vertical channel 602; from top to bottom, the projections of the two adjacent vertical channels 602 from top to bottom do not overlap, so that the flow path of the exhaust gas in the lower chamber 102 is tortuous, the flow direction and speed of the exhaust gas are changed, and the exhaust gas forms a turbulent state in the gas cooling tank 1, thereby enhancing the heat exchange effect and improving the cooling efficiency of the exhaust gas.

[0042] Preferably, Figure 3 As shown, a gap 603 is formed between the top baffle 6 and the partition 103 , the vertical channel 602 is provided between the top baffle 6 and the inner wall surface of the gas cooling tank 1 , and the gas inlet 301 leads to the gap 603 .

[0043] The gas to be cooled (exhaust gas) entering from the gas inlet 301 first flows into the gap 603, which is beneficial to extend the flow path of the gas to be cooled in the lower chamber 102 and is beneficial to fully cool the gas to be cooled.

[0044] Preferably, Figure 3 As shown, the upper edge of the gas outlet 302 is connected to the lower plate surface of the lowest baffle 6.

[0045] The gas to be cooled flows downward along the air flow channel 601 and the vertical channel 602 in the lower chamber 102. The gas to be cooled that has not been cooled flows to the bottom of the lowest baffle plate 6 and is then discharged from the gas outlet 302. The upper edge of the gas outlet 302 is connected to the lower plate surface of the lowest baffle plate 6, which can prevent the gas to be cooled from gathering for a long time under the lowest baffle plate 6 and being unable to be discharged.

[0046] Preferably, Figure 3 As shown, a liquid level meter 701 is provided on the gas cooling tank 1 , and the liquid level meter 701 is used to monitor the liquid level of the liquid nitrogen in the upper chamber 101 .

[0047] The liquid inlet 201 is provided with a liquid inlet pipe 2011 , and the liquid inlet pipe 2011 is provided with a control valve 702 .

[0048] The liquid level of liquid nitrogen in the upper chamber 101 is monitored by the liquid level meter 701, and the liquid level of liquid nitrogen is controlled by the control valve 702, so that the amount of liquid nitrogen in the gas cooling tank 1 can be maintained at an appropriate level, for example, the liquid level of liquid nitrogen in the upper chamber 101 is between 20% and 80%; when it is lower than 20%, the opening of the control valve 702 is increased, and when it is higher than 80%, the opening of the control valve 702 is reduced.

[0049] The liquid level meter 701 can be a magnetic flap liquid level meter, that is, an on-site liquid level meter; when the liquid level meter 701 is set as an on-site liquid level meter, it is helpful for the staff to intuitively understand the height of the liquid nitrogen level and facilitate the staff to control the amount of liquid nitrogen charged into the gas cooling tank 1.

[0050] Preferably, Figure 4 As shown, there are multiple heat exchange tubes 5, and the lower end opening of each heat exchange tube 5 is closed.

[0051] A sealing plate may be provided to seal the lower end openings of all heat exchange tubes 5 at the same time. The sealing plate has a certain flow-guiding effect on the gas to be cooled, which is beneficial to further extend the flow path of the gas and is beneficial to the cooling of the gas to be cooled.

[0052] The lower end opening of each heat exchange tube 5 is closed, and any two heat exchange tubes 5 can only be connected through the upper chamber 101; on the one hand, the processing difficulty is reduced; on the other hand, after the liquid nitrogen is vaporized into gas in the heat exchange tube, it can only flow upward, and the gaseous nitrogen formed by the vaporization of liquid nitrogen in each heat exchange tube 5 does not affect each other, thereby avoiding vibration caused by the gaseous nitrogen flowing in different heat exchange tubes 5.

[0053] Preferably, there are multiple heat exchange tubes 5, and the lower end openings of at least two of the heat exchange tubes 5 are connected to each other.

[0054] By interconnecting the lower end openings of at least two heat exchange tubes 5, it is beneficial to ensure that the level of liquid nitrogen inside the two interconnected heat exchange tubes is basically consistent, thereby ensuring the consistency of the refrigeration performance of the interconnected heat exchange tubes 5 and improving the cooling effect on the gas to be cooled.

[0055] Preferably, Figure 3 As shown, a box body 703 is disposed in the lower chamber 102 , and a plurality of heat exchange tubes 5 are provided, and the lower end openings of the plurality of heat exchange tubes 5 are all connected to the inner cavity of the box body 703 .

[0056] The box body 703 is made of a heat-conducting plate, such as an aluminum plate. The box body 703 is arranged in the lower chamber 102, and multiple heat exchange tubes 5 are provided, and the lower end openings of the multiple heat exchange tubes 5 are connected to the inner cavity of the box body 703. When the amounts of liquid nitrogen in the multiple heat exchange tubes 5 are different, the liquid nitrogen flows downward into the box body 703 to mix. On the one hand, the liquid nitrogen can exchange heat with the gas to be cooled in the box body 703. On the other hand, the height of the liquid nitrogen in each heat exchange tube 5 is basically the same, so that the temperature of the multiple heat exchange tubes 5 is basically the same, thereby avoiding excessive temperature differences between the heat exchange tubes 5 and reducing the cooling efficiency of the gas to be cooled.

[0057] Preferably, the minimum vertical distance between the gas outlet 202 and the partition 103 is greater than the preset liquid level height.

[0058] The “preset liquid level height” refers to the maximum liquid level allowed for liquid nitrogen in the gas cooling tank 1. Too much liquid nitrogen puts a greater pressure on the gas cooling tank 1. When too much liquid nitrogen enters the gas cooling tank 1, the amount of liquid nitrogen entering the gas cooling tank 1 is controlled.

[0059] The gas cooling tank 1 comprises a top cover 104 , and the liquid inlet 201 and the gas outlet 202 are both arranged on the top cover 104 .

[0060] The utility model also provides a carbon fiber production system, such as Figure 1 As shown, it includes a liquid nitrogen storage tank 801, a carbonization furnace 802 and a gas cooling tank 1; the outlet of the liquid nitrogen storage tank 801 is connected to the liquid inlet 201, and the gas outlet 202 is connected to the protective gas inlet of the carbonization furnace 802.

[0061] The liquid nitrogen discharged from the liquid nitrogen storage tank 801 first flows into the gas cooling tank 1, where the liquid nitrogen vaporizes into a gaseous state and releases cold energy. The released cold energy is used to cool the gas to be cooled, and the nitrogen is discharged from the gas outlet 202 and enters the carbonization furnace 802 indirectly or directly as a protective gas. The cold energy of the vaporized liquid nitrogen is cleverly used to cool the gas to be cooled, and the liquid nitrogen is comprehensively utilized, which saves energy and increases revenue. The carbonization furnace 802 includes a high carbon furnace and a low carbon furnace, and the nitrogen enters the high carbon furnace and the low carbon furnace respectively.

[0062] The carbon fiber production system may also be provided with a recovery tank 804 , which is connected to the drain port 4 .

[0063] Preferably, Figure 1 As shown, the carbon fiber production system further includes a liquid nitrogen vaporization device 803 , and the outlet of the liquid nitrogen storage tank 801 is also connected to the inlet of the liquid nitrogen vaporization device 803 .

[0064] When the carbonization furnace 802 has a greater demand for nitrogen, the outlet of the liquid nitrogen storage tank 801 is also connected to the inlet of the liquid nitrogen vaporization device 803 without passing through the gas cooling tank 1, and the liquid nitrogen is quickly vaporized in the liquid nitrogen vaporization device 803, so that a sufficient amount of liquid nitrogen discharged from the liquid nitrogen storage tank 801 enters the liquid nitrogen vaporization device 803 and is vaporized into a gaseous state. The nitrogen vaporized into a gaseous state from the liquid nitrogen vaporization device 803 is mixed with the gaseous nitrogen discharged from the gas cooling tank 1 and is passed to the carbonization furnace 802 as a protective gas.

[0065] It is easy for those skilled in the art to understand that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0066] The above is only a preferred embodiment of the utility model, and is not intended to limit the utility model. Any modifications, equivalent replacements and improvements made within the spirit and principles of the utility model should be included in the protection scope of the utility model. The above is only a preferred implementation of the utility model. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the utility model, and these improvements and variations should also be regarded as the protection scope of the utility model.

Claims

1. A gas cooling tank, characterized in that: A partition (103) is provided in the gas cooling tank (1), and the partition (103) divides the inner cavity of the gas cooling tank (1) into an upper chamber (101) and a lower chamber (102); the upper chamber (101) is provided with a liquid inlet (201) and a gas outlet (202); the lower chamber (102) is provided with a gas inlet (301) and a gas outlet (302); and a liquid discharge port (4) is provided at the bottom of the lower chamber (102); the liquid inlet (201) is used for charging liquid nitrogen, and the gas inlet (301) is used for charging gas to be cooled; At least one heat exchange tube (5) is also vertically arranged in the gas cooling tank (1); the upper end opening of the heat exchange tube (5) is connected to the upper chamber (101), and the lower end of the heat exchange tube (5) is located in the lower chamber (102); the inner cavity of the heat exchange tube (5) is isolated from the lower chamber (102).

2. The gas cooling tank according to claim 1, characterized in that: A plurality of baffles (6) are disposed transversely in the lower chamber (102), and a zigzag channel is formed between the plurality of baffles (6); the gas to be cooled entering the lower chamber (102) from the gas inlet (301) flows through the zigzag channel; At least one heat exchange tube (5) passes through the tortuous channel.

3. The gas cooling tank according to claim 2, characterized in that: A plurality of baffles (6) are laterally fixed on the inner wall of the gas cooling tank (1) in sequence from top to bottom, an airflow channel (601) is formed between two adjacent baffles (6), and at least one heat exchange tube (5) passes through at least one of the airflow channels (601); two adjacent airflow channels (601) are connected via a vertical channel (602); from top to bottom, the projections of two adjacent vertical channels (602) from top to bottom do not overlap; the zigzag channel includes the airflow channel (601) and the vertical channel (602).

4. The gas cooling tank according to claim 3, characterized in that: A gap (603) is formed between the top baffle (6) and the partition (103), the vertical channel (602) is provided between the top baffle (6) and the inner wall surface of the gas cooling tank (1), and the gas inlet (301) leads to the gap (603).

5. The gas cooling tank according to claim 1, characterized in that: The gas cooling tank (1) is provided with a liquid level meter (701), and the liquid level meter (701) is used to monitor the liquid level of liquid nitrogen in the upper chamber.

6. The gas cooling tank according to claim 1, characterized in that: There are a plurality of heat exchange tubes (5), and the lower end opening of each heat exchange tube (5) is closed.

7. The gas cooling tank according to claim 1, characterized in that: There are a plurality of heat exchange tubes (5), and the lower end openings of at least two of the heat exchange tubes (5) are interconnected.

8. The gas cooling tank according to claim 7, characterized in that: A box body (703) is disposed in the lower chamber (102), and the lower end openings of at least two of the heat exchange tubes (5) are in communication with the inner cavity of the box body (703).

9. A carbon fiber production system, characterized in that: It comprises a liquid nitrogen storage tank (801), a carbonization furnace (802), a polymerization section, a spinning section and the gas cooling tank according to any one of claims 1 to 8; the outlet of the liquid nitrogen storage tank (801) is connected to the liquid inlet (201), and the gas outlet (202) is connected to the protective gas inlet of the carbonization furnace (802); the gas to be cooled is the tail gas generated by the polymerization section and the spinning section.

10. The carbon fiber production system according to claim 9, characterized in that: The carbon fiber production system further comprises a liquid nitrogen vaporization device (803), and the outlet of the liquid nitrogen storage tank (801) is also connected to the inlet of the liquid nitrogen vaporization device (803).

Images