Steam condensate recycling device in the heat setting of dry PAN-based carbon fiber precursor

Abstract

This utility model belongs to the field of steam condensate recycling technology, specifically relating to a steam condensate recycling device for heat setting of dry PAN-based carbon fiber precursor. The steam condensate recycling device for heat setting of dry PAN-based carbon fiber precursor includes a heat setting device, a premixer, a steam ejector, a washing tank, and a heat exchanger connected in sequence. The input ends of the premixer and the steam ejector are both connected to a high-pressure steam pipeline, and the high-pressure steam pipeline has branches connected to the heat setting device. This utility model's steam condensate recycling device for heat setting of dry PAN-based carbon fiber precursor achieves efficient utilization of condensate waste heat by recovering both high-temperature and low-temperature condensate. The premixer and steam ejector work together, with a reasonable structural design. Optimized processing flow using ramps, spiral plates, and other structural elements, along with multi-path mixing of high-pressure steam and high-temperature condensate, improves efficiency and ensures stable conversion of low-pressure steam.

Description

Technical Field

[0001] This utility model belongs to the field of steam condensate recycling technology, specifically relating to a steam condensate recycling device in the heat setting of dry PAN-based carbon fiber precursor. Background Technology

[0002] In the dry-process heat setting of PAN-based carbon fiber precursor, steam plays an indispensable role. During this process, steam generates a large amount of condensate through heat exchange. However, the condensate is not entirely liquid, and when the pressure suddenly drops during the discharge process, some liquid water may instantly vaporize into steam, forming a phenomenon known as "flash evaporation," leading to an increase in the steam content of the condensate. Currently, most companies, in actual production, simply exchange heat with demineralized water and cool it with circulating water before recycling it. This method not only fails to fully and rationally utilize the excess heat of the condensate but also consumes a large amount of energy during the cooling process, resulting in a double waste of energy.

[0003] CN222143676U discloses a waste heat recovery and energy-saving system for a steam dryer used in textiles. The system consists of a dryer, a high-temperature air source heat pump, a flash tank, and a steam ejector. Through the pipeline connection between the various devices, it realizes the circulation and heat exchange of different fluids such as fresh steam, humid waste gas, and condensate. By utilizing waste heat in stages, it improves the temperature of fresh air and the efficiency of the dryer, converts waste heat into high-quality steam, reduces steam consumption and cost, and recovers steam leaking from the steam trap to further utilize the waste heat of the condensate. However, in the process of medium-pressure steam conversion, it is necessary to rely on the high-temperature air source heat pump and the flash tank to first convert the condensate into low-pressure steam, which is a cumbersome process. Moreover, the high-temperature air source heat pump is easily affected by the ambient temperature. When the ambient temperature is too low, the heating efficiency decreases, which will affect the waste heat recovery effect.

[0004] Therefore, it is necessary to design a simple steam condensate recycling device for the heat setting of dry PAN-based carbon fiber precursor. By rationally arranging the steam condensate and high-pressure steam, the waste heat of the steam condensate and the recycling of the condensate can be realized. Utility Model Content

[0005] The purpose of this invention is to overcome the defects of the existing technology and provide a steam condensate recycling device in the heat setting of dry PAN-based carbon fiber precursor. It achieves efficient utilization of condensate waste heat by recovering high-temperature condensate and low-temperature condensate. The premixer and steam ejector work together, the structure is reasonably designed, and the process is optimized by the slope, spiral plate and other structures. The high-pressure steam and high-temperature condensate are mixed through multiple pathways, which improves the efficiency of use and ensures the stable conversion of low-pressure steam.

[0006] The steam condensate recycling device for the dry PAN-based carbon fiber precursor heat setting of this utility model includes a heat setting device, a premixer, a steam ejector, a water washing tank and a heat exchanger connected in sequence. The input ends of the premixer and the steam ejector are both connected to a high-pressure steam pipeline, and the high-pressure steam pipeline is connected to the heat setting device.

[0007] Preferably, the heat setting device is provided with steam spray guns on the upper and lower inner walls, and the steam input end of the steam spray guns is connected to the high-pressure steam pipeline; the bottom inner wall of the heat setting device is a sloping structure, and a high-temperature condensate outlet is provided on the lower side of the sloping structure, and the high-temperature condensate outlet is provided with a pipeline connected to the premixer.

[0008] Preferably, the steam ejector outlet is provided with a pipeline connected to the steam inlet of the washing tank, the high-pressure steam pipeline is provided with a branch connected to the steam inlet of the washing tank, and the low-temperature condensate outlet at the bottom of the washing tank is connected to the shell-side inlet at the top of the heat exchanger.

[0009] Preferably, the heat exchanger has a shell-side outlet at the bottom, which is connected to the demineralized water pipeline network; the heat exchanger has a tube-side inlet at the bottom, which is connected to the washing water pipeline; and the heat exchanger has a tube-side outlet at the top, which is connected to the washing water inlet of the washing tank.

[0010] Preferably, the premixer is provided with a high-temperature condensate inlet at the top, the high-temperature condensate inlet pipe extends into the premixer, and the outlet end of the high-temperature condensate inlet pipe is provided with a hemispherical guide shroud, and the hemispherical guide shroud is provided with an outlet hole.

[0011] Preferably, the premixer has a spirally arranged steam coil on its inner wall, and the steam coil has steam injection holes. The input end of the steam coil is connected to a high-pressure steam pipeline. The premixer has an axially arranged spiral plate, which is composed of left-handed and right-handed unit plates. The left-handed and right-handed unit plates are arranged alternately inside the premixer. A porous baffle plate is provided at the outlet of the premixer, and circular through holes are evenly distributed on the porous baffle plate.

[0012] Preferably, the steam ejector input end is provided with a steam condensate inlet and a high-pressure steam inlet, the steam condensate inlet is located on the upper wall of the steam ejector input end, and the high-pressure steam inlet is located on the side wall of the steam ejector input end; the steam ejector output end cylinder is conical.

[0013] Preferably, the high-pressure steam inlet pipe extends into the steam ejector, and the steam output end of the high-pressure steam inlet pipe is connected to a conical guide shroud.

[0014] Preferably, the steam condensate inlet is a sleeve structure, which is divided into an inner tube and an outer tube. The inlet of the inner tube is connected to the output end of the premixer, and the outlet of the inner tube is connected to an atomizing nozzle. The outer tube is connected to a high-pressure steam pipeline, and the length of the outer tube extending into the steam ejector is less than the sum of the lengths of the inner tube and the atomizing nozzle extending into the steam ejector.

[0015] Specifically, the steam condensate recycling device in the dry PAN-based carbon fiber precursor heat setting process operates as follows: 2MPa high-pressure steam from the high-pressure steam network enters the heat setting device through pipelines, and steam spray guns on the upper and lower inner walls of the heat setting device spray out steam to heat set the PAN-based carbon fiber precursor; the high-temperature condensate generated during the heat setting process flows to the high-temperature condensate outlet on the lower side of the slope due to the sloping inner wall of the bottom of the heat setting device, and then enters the premixer through pipelines.

[0016] The high-temperature condensate inlet pipe at the top of the premixer introduces the high-temperature condensate, and the hemispherical guide shroud and the outlet hole at its outlet end ensure that the high-temperature condensate is evenly dispersed. At the same time, high-pressure steam is connected to the spirally arranged steam coils on the inner wall of the premixer through the pipeline. The steam is ejected from the steam injection hole. The axial spiral plates inside the premixer are arranged alternately with left-handed and right-handed unit plates, which makes the high-temperature condensate and steam fully mixed and accelerates the vaporization of the steam and condensate. Finally, the condensate is further mixed by the porous baffle plate at the outlet of the premixer before flowing out.

[0017] The premixed steam condensate enters from the steam condensate inlet on the upper wall of the steam ejector. The steam condensate inlet is a sleeve structure. The inner tube introduces the steam condensate output from the premixer and sprays it out through the atomizing nozzle. The outer tube introduces high-pressure steam to ensure the vaporization stability of the steam condensate. The high-pressure steam enters from the high-pressure steam inlet on the side wall of the input end of the steam ejector. The high-pressure steam inlet pipe extends into the steam ejector. The conical guide hood at its steam output end guides the steam flow. Inside the steam ejector, the steam condensate vaporizes into low-pressure steam.

[0018] Low-pressure steam is delivered to the washing tank via pipelines. In addition, a branch of the high-pressure steam pipeline is directly connected to the steam inlet of the washing tank. This is used to provide the heat required by the washing tank during the initial operation when there is no low-pressure steam. The low-temperature condensate generated at the bottom of the washing tank flows out from the low-temperature condensate outlet and enters the shell side of the heat exchanger. The low-temperature condensate flows in the shell side of the heat exchanger. The washing water enters from the bottom tube side inlet of the heat exchanger and exchanges heat with the low-temperature condensate in the shell side. The water after heat exchange flows out from the top tube side outlet of the heat exchanger and returns to the washing tank through pipelines for use as washing water. The low-temperature condensate after heat exchange flows out from the bottom shell side outlet of the heat exchanger and is connected to the demineralized water pipeline network. It can be directly recycled without further dilution, cooling or heat exchange.

[0019] Compared with the prior art, the beneficial effects of this utility model are as follows: The steam condensate recycling device in the dry-process PAN-based carbon fiber precursor heat setting of this utility model achieves effective recycling of steam condensate by recycling the high-temperature condensate at the bottom of the heat setting device and the low-temperature condensate at the bottom of the washing tank; the internal structure design of the heat setting device, premixer and steam ejector is conducive to the full mixing of high-temperature condensate and high-pressure steam, improving the conversion efficiency of steam condensate; finally, the high-pressure steam pipeline is set with multiple branches, realizing the rational utilization of high-pressure steam in different links, improving the steam utilization efficiency, and meeting the steam requirements of different equipment and processes. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the steam condensate recycling device in the dry PAN-based carbon fiber precursor heat setting of this utility model.

[0021] Figure 2 This is a schematic diagram of the premixer in the steam condensate recycling device for the dry PAN-based carbon fiber precursor heat setting of this utility model.

[0022] Figure 3 This is a schematic diagram of the steam ejector in the steam condensate recycling device for the dry-process PAN-based carbon fiber precursor heat setting of this utility model.

[0023] In the diagram: 1. Heat setting device; 101. Steam spray gun; 2. Premixer; 201. High-temperature condensate inlet; 202. Hemispherical guide hood; 203. Steam coil; 204. Spiral plate; 205. Porous baffle plate; 3. Steam ejector; 301. Steam condensate inlet; 302. High-pressure steam inlet; 303. Conical guide hood; 304. Outer pipe; 305. Inner pipe; 306. Atomizing nozzle; 4. Washing tank; 5. Heat exchanger; 6. High-pressure steam pipeline; 7. Washing water pipeline; 8. Demineralized water pipeline network. Detailed Implementation

[0024] The specific technical solution of this utility model will be further described below with reference to the accompanying drawings.

[0025] like Figures 1-3As shown, the steam condensate recycling device in the dry-process PAN-based carbon fiber precursor heat setting includes a heat setting device 1, which is connected to a premixer 2. The premixer 2 is connected to a steam ejector 3 via a pipeline. The outlet of the steam ejector 3 is connected to the steam inlet of a washing tank 4. The low-temperature condensate outlet at the bottom of the washing tank 4 is connected to the shell-side inlet at the top of a heat exchanger 5. The input ends of both the premixer 2 and the steam ejector 3 are connected to a high-pressure steam pipeline 6. A branch of the high-pressure steam pipeline 6 is connected to the heat setting device 1. The heat exchanger 5 has a shell-side outlet at the bottom, which is connected to a demineralized water pipeline network 8. The bottom tube-side inlet of the heat exchanger 5 is connected to a washing water pipeline 7. The top tube-side outlet of the heat exchanger 5 is connected to the washing water inlet of the washing tank 4. The high-pressure steam pipeline 6 has a branch connected to the steam inlet of the washing tank 4.

[0026] The heat setting device 1 is provided with steam spray guns 101 on the upper and lower inner walls, and the steam input end of the steam spray guns 101 is connected to the branch of the high-pressure steam pipeline 6; the bottom inner wall of the heat setting device 1 is a sloping structure, and a high-temperature condensate outlet is provided on the lower side of the sloping structure, and a pipeline connected to the premixer 2 is provided at the high-temperature condensate outlet.

[0027] The premixer 2 is provided with a high-temperature condensate inlet 201 at the top. The pipe of the high-temperature condensate inlet 201 extends into the premixer 2. A hemispherical guide hood 202 is provided at the outlet end of the pipe of the high-temperature condensate inlet 201. An outlet hole is provided on the hemispherical guide hood 202.

[0028] The premixer 2 has a spirally arranged steam coil 203 on its inner wall, and steam injection holes on the steam coil 203. The input end of the steam coil 203 is connected to the high-pressure steam pipeline 6. The premixer 2 has an axially arranged spiral plate 204 inside, which is composed of left-handed and right-handed unit plates. The left-handed and right-handed unit plates are arranged alternately inside the premixer 2. The premixer 2 has a porous baffle plate 205 at its outlet, and the porous baffle plate 205 has evenly distributed circular through holes.

[0029] The steam ejector 3 is provided with a steam condensate inlet 301 and a high-pressure steam inlet 302 at its input end. The steam condensate inlet 301 is located on the upper wall of the input end of the steam ejector 3, and the high-pressure steam inlet 302 is located on the side wall of the input end of the steam ejector 3. The output end of the steam ejector 3 is conical.

[0030] The high-pressure steam inlet 302 pipe extends into the steam ejector 3, and the steam output end of the high-pressure steam inlet 302 pipe is connected to a conical guide shroud 303.

[0031] The steam condensate inlet 301 is a sleeve structure, which is divided into an inner tube 305 and an outer tube 304. The inlet of the inner tube 305 is connected to the output end of the premixer 2, and the outlet of the inner tube 305 is connected to an atomizing nozzle 306. The outer tube 304 is connected to the high-pressure steam pipeline 6. The length of the outer tube 304 extending into the steam ejector 3 is less than the sum of the lengths of the inner tube 305 and the atomizing nozzle 306 extending into the steam ejector 3.

[0032] The steam condensate recycling device in the dry PAN-based carbon fiber precursor heat setting process is as follows: 2MPa high-pressure steam from the high-pressure steam network enters the heat setting device 1 through the pipeline. Steam spray guns 101 on the upper and lower inner walls of the heat setting device 1 spray out steam to heat set the PAN-based carbon fiber precursor. The high-temperature condensate generated during the heat setting process flows to the high-temperature condensate outlet on the lower side of the slope because the bottom inner wall of the heat setting device 1 has a sloping structure. Then it enters the premixer 2 through the pipeline.

[0033] The high-temperature condensate inlet 201 at the top of the premixer 2 introduces the high-temperature condensate. The hemispherical guide shroud 202 at the outlet end of the pipe and the outlet hole on it make the high-temperature condensate evenly dispersed. At the same time, high-pressure steam is connected to the spirally arranged steam coil 203 on the inner wall of the premixer 2 through the pipeline. The steam is ejected from the steam injection hole. The axial spiral plate 204 inside the premixer 2 is arranged with alternating left-hand and right-hand unit plates, which makes the high-temperature condensate and steam fully mixed and accelerates the vaporization of steam and condensate. Finally, it flows out after being further mixed by the porous baffle 205 at the outlet of the premixer 2.

[0034] The premixed steam condensate enters from the steam condensate inlet 301 on the upper wall of the steam ejector 3. The steam condensate inlet 301 is a sleeve structure. The inner pipe 305 introduces the steam condensate output from the premixer 2 and sprays it out through the atomizing nozzle 306. The outer pipe 304 introduces high-pressure steam to ensure the vaporization stability of the steam condensate. The high-pressure steam enters from the high-pressure steam inlet 302 on the side wall of the input end of the steam ejector 3. The high-pressure steam inlet 302 extends into the steam ejector 3. The conical guide shroud 303 at its steam output end guides the steam flow. Inside the steam ejector 3, the steam condensate vaporizes into low-pressure steam.

[0035] Low-pressure steam is transported to the washing tank 4 through pipelines. In addition, the high-pressure steam pipeline 6 has a branch that is directly connected to the steam inlet of the washing tank 4. This is used to provide the heat required by the washing tank 4 with high-pressure steam in the early stage of operation when there is no low-pressure steam. When there is low-pressure steam, the valve is slowly closed to reduce the amount of high-pressure steam used until the low-pressure steam can meet the actual needs. The condensate generated in the washing tank 4 flows out from the low-temperature condensate outlet and enters the shell side of the heat exchanger 5. The low-temperature condensate flows in the shell side of the heat exchanger 5. The washing water enters from the bottom tube side inlet of the heat exchanger 5 and exchanges heat with the low-temperature condensate in the shell side in the tube side. The water after heat exchange flows out from the top tube side outlet of the heat exchanger 5 and returns to the washing tank 4 through pipelines for use as washing water. The low-temperature condensate after heat exchange flows out from the bottom shell side outlet of the heat exchanger 5 and is connected to the demineralized water pipeline network 8. It can be directly recycled without further dilution, cooling or heat exchange.

Claims

1. A device for recycling steam condensate in the heat setting of dry- process PAN-based carbon fiber precursor, characterized in that, The device includes a heat setting device (1), which is connected to a premixer (2). The premixer (2) is connected to a steam ejector (3) via a pipeline. The outlet of the steam ejector (3) is provided with a pipeline connected to the steam inlet of a water washing tank (4). The low-temperature condensate outlet at the bottom of the water washing tank (4) is connected to the upper shell-side inlet of a heat exchanger (5). The input ends of the premixer (2) and the steam ejector (3) are both connected to a high-pressure steam pipeline (6), which is connected to the heat setting device (1). The heat exchanger (5) is provided with a shell-side outlet at the bottom, which is connected to the demineralized water pipeline (8); the bottom tube-side inlet of the heat exchanger (5) is connected to the washing water pipeline (7), and the top tube-side outlet of the heat exchanger (5) is provided with a pipeline connected to the washing water inlet of the washing tank (4).

2. The steam condensate recycling device for heat setting of dry PAN-based carbon fiber precursor according to claim 1, characterized in that, The high-pressure steam pipeline (6) is provided with a branch line connected to the steam inlet of the washing tank (4).

3. The steam condensate recycling device for heat setting of dry PAN-based carbon fiber precursor according to claim 1, characterized in that, The heat setting device (1) is equipped with steam spray guns (101) on both the upper and lower inner walls. The steam input end of the steam spray gun (101) is connected to the high-pressure steam pipeline (6). The bottom inner wall of the heat setting device (1) is a sloping structure. A high-temperature condensate outlet is provided on the lower side of the sloping structure. A pipeline connected to the premixer (2) is provided at the high-temperature condensate outlet.

4. The steam condensate recycling device for heat setting of dry PAN-based carbon fiber precursor according to claim 1, characterized in that, The premixer (2) is provided with a high-temperature condensate inlet (201) at the top. The high-temperature condensate inlet (201) pipe extends into the premixer (2). The outlet end of the high-temperature condensate inlet (201) pipe is provided with a hemispherical guide hood (202). The hemispherical guide hood (202) is uniformly provided with outlet holes.

5. The steam condensate recycling device for heat setting of dry PAN-based carbon fiber precursor according to claim 1, characterized in that, The premixer (2) has a spirally arranged steam coil (203) on its inner wall, and a steam injection hole is provided on the steam coil (203). The input end of the steam coil (203) is connected to the high-pressure steam pipeline (6). The premixer (2) has an axially arranged spiral plate (204) inside, which is composed of left-handed and right-handed unit plates. The left-handed and right-handed unit plates are arranged alternately inside the premixer (2). A porous baffle plate (205) is provided at the outlet of the premixer (2), and circular through holes are evenly distributed on the porous baffle plate (205).

6. The steam condensate recycling device for heat setting of dry PAN-based carbon fiber precursor according to claim 1, characterized in that, The steam ejector (3) is provided with a steam condensate inlet (301) and a high-pressure steam inlet (302) at its input end. The steam condensate inlet (301) is located on the upper wall of the input end of the steam ejector (3), and the high-pressure steam inlet (302) is located on the side wall of the input end of the steam ejector (3). The output end of the steam ejector (3) is conical.

7. The steam condensate recycling device for heat setting of dry PAN-based carbon fiber precursor according to claim 6, characterized in that, The high-pressure steam inlet (302) pipe extends into the steam ejector (3), and the steam output end of the high-pressure steam inlet (302) pipe is connected to a conical guide shroud (303).

8. The steam condensate recycling device for heat setting of dry PAN-based carbon fiber precursor according to claim 6, characterized in that, The steam condensate inlet (301) is a sleeve structure, which is divided into an inner tube (305) and an outer tube (304). The inlet of the inner tube (305) is connected to the output end of the premixer (2), and the outlet of the inner tube (305) is connected to an atomizing nozzle (306). The outer tube (304) is connected to the high-pressure steam pipeline (6). The length of the outer tube (304) extending into the steam ejector (3) is less than the sum of the lengths of the inner tube (305) and the atomizing nozzle (306) extending into the steam ejector (3).

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