Device for liquid-solid phase efficient separation and trapping of tar, broken filaments and like in carbon fiber tail gas

Abstract

The invention discloses a device for liquid-solid phase efficient separation and trapping of tar, broken filaments and the like in carbon fiber tail gas, and belongs to the field of tail gas treatment. By utilizing a supergravity technology, liquid-solid phase trapping is realized by adding a silk screen filler in a rotating bed, and separation of a gas phase (process waste gas) and a liquid / solid phase (tar / broken filament fiber) is promoted under the action of rotating centrifugal force. The operation of the device specifically comprises the following stages: the device is firstly connected into a tail gas outlet of a polyacrylonitrile-based carbon fiber production line, then a rotating bed separation trap is started, and tail gas of a carbon fiber production device is introduced into the separation trap through a gas inlet of the device and flows through a packed bed layer; and impurity components such as tar and broken filament fibers are intercepted and removed through a cascade ring and a Pall ring. The tar and the broken filament fibers are difficult to separate, so that the total mass of the tar and the broken filament fibers separated and removed by the device is detected by adopting a mass difference method. Compared with an inertial dust collector, the method has the advantage that the classification efficiency of tar and broken filament fibers can be improved by 88% or above.

Description

Technical Field

[0001] The present invention relates to the related fields of environmental protection and industrial waste gas treatment, and in particular to a method and device for efficiently removing tar and lint fibers from process waste gas discharged by a carbon fiber production device in a rotating bed separation collector. Background Art

[0002] Carbon fiber has the characteristics of high strength, high modulus, high temperature resistance, corrosion resistance, fatigue resistance, creep resistance, excellent electrical and thermal conductivity, etc. In the production process of polyacrylonitrile (PAN)-based carbon fiber, crosslinking, cyclization, and condensed ring formation occur within and between PAN molecules, gradually forming a chaotic layer graphite structure. According to the production process, in the production process of polyacrylonitrile-based carbon fiber, its pre-oxidized fiber will produce many gaseous cracking components in the low-temperature carbonization link of about 300°C. When these gaseous cracking components enter the carbonization furnace together with nitrogen, due to the relatively low temperature at the furnace mouth, the gaseous cracking components will condense into liquid, relatively large molecular weight, and sticky thermal cracking products, which are called polyacrylonitrile-based carbon fiber carbonization tar. These tars will form glue droplets and fine carbon fiber filaments that are discharged together with the air flow, which can easily cause blockage of the pipeline and serious deactivation of the subsequent cyanide-containing tail gas purification catalyst, and need to be captured and removed. The above falls within the scope of treatment of this patent.

[0003] Ultra-gravity separation is a new separation technology. As early as 1979, the British Imperial Chemical Company proposed installing various mesh materials on the rotor to promote separation. In recent years, a large number of ultra-gravity rotating bed technologies have been used internationally for gas / liquid / solid three-phase separation. In patent JP2017506424A, China Electric Power Corporation proposed to separate tar by using a gas-liquid separator similar to an ultra-gravity device; in US202318516019A, GTI Energy designed an ultra-gravity rotating bed separation device with a hollow central axis and two independent concentric liquid paths. The maximum separation efficiency for multi-liquid phase components is about 90%, but the patented design device is difficult to use for gas-liquid separation.

[0004] Domestically, a variety of removal devices have been developed to remove similar substances. For example, Tianjin Ranjiesi Industrial Equipment Co., Ltd. disclosed in its patent CN 118718574 A its pipeline tar separation and degradation treatment device, which includes a flue gas pipeline and a separation device body, uses a guide module and a filter grid to filter the tar, and provides a swing nozzle to achieve separation; Zhejiang Longying Environmental Technology Co., Ltd. disclosed in its patent CN 118356735 A a technology that uses an adsorption zone that adsorbs and discharges volatile organic vapor (VOCs) molecules, a desorption zone that uses high-temperature flue gas for desorption and regeneration to form a high-concentration exhaust gas, and a cooling zone to filter particulate matter in the exhaust gas multiple times; Zhejiang University of Technology disclosed in patent CN 202410736314.1 a high-gravity rotating bed using a gas-liquid diversion liquid distributor, and revealed the design influence of baffles on gas-liquid separation. All three patents can increase the removal efficiency to more than 70% and facilitate multi-phase separation; however, from the overall performance point of view, the rotating bed has a significant advantage in enhanced mass transfer compared to the fixed bed. For example, the rotating bed of CN 202410736314.1 can omit the swinging nozzle unit of CN118718574 A and achieve the same separation efficiency.

[0005] There are currently some relatively effective solutions for common gas-liquid separation devices. However, for the tar components in carbon fiber exhaust, there are problems such as high viscosity, easy solidification, and difficulty in removal. The currently commonly used supergravity gas-liquid separation technology basically adopts a combination of centrifugation and baffles to separate gas and liquid components. For example, patent CN 202411550716.9 of Nanjing Aobo Industrial Intelligent Technology Research Institute Co., Ltd. This type of technology cannot fundamentally solve the problem of tar adhesion and blockage, and requires frequent replacement of rotors. Therefore, it is difficult to improve the separation efficiency of tar gas-liquid phases and the continuity of production, and the purification cost remains high. This patent adopts an alternating method of spraying and rotary interception to effectively remove the tar adhering to the rotor and maintain long-term and efficient operation of the equipment. Summary of the Invention

[0006] The main technical problem solved by the present invention is to effectively treat the cyanide-containing process waste gas generated by carbon fiber production. It provides a method for deep removal of tar and filamentous fibers in a rotating bed separation collector, which can solve the problems of tar adhesion and clogging of pipelines and deactivation of subsequent exhaust gas purification catalysts, and significantly improve the liquid-solid phase separation efficiency by more than 88%.

[0007] In order to solve the above technical problems, the present invention adopts a technical solution: a device for efficiently separating and capturing liquid and solid phases of tar, hair, etc. in carbon fiber tail gas, characterized by: a rotating bed separation collector, comprising: a shell (5), a liquid distributor (10), a high-gravity rotating bed (4), a driving motor (1), and a storage box (13);

[0008] The shell (5) is provided with a high-gravity rotating bed (4) corresponding to the radial surface. The high-gravity rotating bed (4) divides the shell (5) into two parts, the upper part and the lower part. The upper part of the high-gravity rotating bed (4) in the shell (5) is a capture chamber (3), and the lower part of the high-gravity rotating bed (4) is an air inlet chamber (11). The air inlet chamber (11) is a concave structure cavity. An air inlet (14) is provided on the side of the air inlet chamber (11). The air inlet (14) is connected to the gas pipeline through a flange. The bottom of the center of the air inlet chamber (11) is provided with a tar discharge port (15) connected to the storage box below. (13) is connected, and the tar outlet (14) is equipped with a butterfly valve (23); an air outlet (16) is provided on the side of the collecting chamber (3); a driving motor (1) is fixed on the upper part of the outer portion of the shell (5), and the driving motor (1) is fixedly connected to the center of the supergravity rotating bed (4) through a rotating shaft; a radial liquid distributor (10) is provided on one side of the collecting chamber (3), and a plurality of evenly distributed spray nozzles (19) are provided on the liquid distributor (10), and the lower end of the pipeline (17) is connected to the liquid distributor (10) for conveying liquid to the liquid distributor (10);

[0009] The tar outlet, air inlet and outlet are all connected to the corresponding pipelines through flanges. To ensure air tightness, rubber gaskets are inserted into the flanges.

[0010] A heat-insulating layer (7) is provided on the outer side of the shell (5), and a device liner (8) is provided inside the shell, and the heat-insulating layer is in close contact with the shell.

[0011] The liquid distributor (10) is arranged in the collecting chamber (3) and is welded to the cover plate (18) of the shell through a pipe (17). The upper end of the pipe (17) extends outward and is connected to the raw material conversion spray material or gas from the outside. The lower end of the liquid distributor 10 is evenly and linearly arranged with multiple spray nozzles (19) arranged at intervals.

[0012] The high-gravity rotating bed is made of a multi-mesh screen, and two bed layers, an inner bed layer (20) and an outer bed layer (21), are arranged. The inner bed layer (20) and the outer bed layer (21) are filled with fillers; or the high-gravity rotating bed adopts an outer, middle and inner three-layer screen, and the screen mesh increases from the inside to the outside, and the mesh range is 1200 mesh to 300 mesh.

[0013] Preferably, the screen is 800-1200 mesh, with the inner and outer layers having the same mesh size and made of stainless steel. The filler in the inner bed layer (20) is a stainless steel step ring (9), and the filler in the outer layer is a stainless steel ball ring (6); the ball ring and the step ring are both 2-5 cm in diameter. After the screen is installed, the inner and outer layers are filled in sequence and the feed cover is locked; the upper side of the screen and the inner and outer layers are all provided with a filling port and a cover of corresponding size to facilitate the loading and unloading of the filler. The filler can also be other fillers that are resistant to high temperatures of 300°C, or a metal-made regular material with a specific pore structure.

[0014] The filling materials of the rotating bed are usually ball rings and step rings. The process exhaust gas flows through the rotating bed layer through the air inlet, and is fully in contact with the fillers such as ball rings and step rings. The surface tension and screening effect of the screen are used to capture tar and isolate solid phase hair fibers. Then, under the action of centrifugal force, the tar and hair fibers in the exhaust gas are thrown to the wall of the separation collector for separation. Finally, under the action of gravity, it flows along the wall to the bottom of the separation collector and is collected.

[0015] A cover plate (18) is provided on the top of the housing. A drive motor (1) is provided on the outside of the cover plate. Its power output is connected to the supergravity rotating bed (4) to drive the rotating bed to rotate. A steel wire brush (2) is provided at the connection between the inner side of the cover plate and the rotating shaft. The steel wire brush (2) can rub the rotating shaft for a long time to remove tar that may adhere and increase resistance. A metal brush made of aluminum wire is further used and only slightly attached to the periphery of the rotating shaft to reduce the adhesion of tar to the rotating shaft.

[0016] The storage box (13) is located at the lower end of the tar discharge port (15) and is connected via a butterfly valve (23). The storage box (13) is placed on the ground and is completely fitted with the tar discharge port (15) to ensure air tightness.

[0017] The shell (5) is supported by a stainless steel bracket (22) (preferably a vertical bracket), the stainless steel bracket (22) and the shell are connected by welding, and the tar discharge port (15) and the stainless steel bracket (22) are welded together, and the overall stability of the device is ensured by the stainless steel bracket.

[0018] In this embodiment, the materials used for the shell, liquid distributor, high-gravity rotating bed, and storage box need to meet the high temperature requirements of 300°C and wear resistance requirements, so stainless steel or similar high-temperature resistant and strong materials can be used.

[0019] The above-mentioned high gravity rotating bed separation collector can be used for gas-liquid separation of high-viscosity and low-viscosity liquids with a temperature below 300° C. and a maximum viscosity of 300 mPa·s.

[0020] During operation, the tail gas of the polyacrylonitrile-based carbon fiber enters the reaction device through the air inlet (14), and the tar and hairy fibers are filtered by the rotating bed, and the remaining gas leaves the device through the air outlet (16); after the device has been running for a period of time, such as 200 hours, the air inlet (14) and the air outlet (16) are closed, the tar outlet (15) is opened, and the liquid distributor (10) continuously sprays 80°C sodium hydroxide solution for 20 minutes, 80°C pure water for 30 minutes, and 30°C nitrogen for 10 minutes. The liquid (sodium hydroxide solution, water) spraying flow rate is 0.2-0.4 cubic meters per hour, and the gas nitrogen spraying flow rate is 0.8-1.2 cubic meters per hour; the sprayed solution, tar, and hairy fibers are collected in the storage box (13) through the tar outlet (15), completing the removal of tar and hairy fibers; after the tar outlet (15) is completely discharged, the tar outlet (15) is closed, the air inlet (14) and the air outlet (16) are opened, and the gas-liquid separation is continued.

[0021] The temperature range of the polyacrylonitrile-based carbon fiber exhaust gas is between 100 and 300°C; the rotation speed during rotating bed filtration is 800 to 1000 revolutions per minute, the diameter range of the rotating bed is 0.5 to 4 meters, and the exhaust gas flow range is adjusted according to the diameter of the device, with a maximum flow of 1000 standard cubic meters per hour.

[0022] Preferably, the motor and the cover are connected by flanges with a gasket in between to ensure tightness. If the flange connection does not provide sufficient airtightness, welding can be used to connect the motor and the cover.

[0023] Furthermore, the tar is an oily substance formed by hydrocarbon compounds in tail gas obtained by pre-oxidation, high-temperature carbonization and low-temperature carbonization of acrylonitrile.

[0024] Furthermore, the tail gas is a stable airflow that enters from the air inlet and contains solid hair fibers, liquid tar and other components and is mixed with nitrogen, ethylene, propylene, hydrogen cyanide, ammonia and other substances.

[0025] Furthermore, the air inlet temperature of the device is maintained at about 300°C. As the gas passes through the rotor and reaches the outlet, the gas temperature gradually decreases over time. As the temperature drops, tar condenses on the packed bed rotor and inner wall of the high-gravity rotating separation and capture device.

[0026] Furthermore, before spraying, in order to reduce the evaporation of sodium hydroxide solution and water, it is necessary to first close the air inlet of the device and open the lower butterfly valve at the same time to discharge the tar recovered from the lower part of the device. After draining, close the butterfly valve and wait for the device to cool down to below 100°C before starting to spray liquid for washing and purging.

[0027] Preferably, the device adopts one backup and one use line. When performing the purge operation, when the air inlet of the device is closed, the ball valve in the center of the pipeline is switched at the same time to replace the pipeline line, and the backup device is used to ensure the continuous operation of the separation and capture system.

[0028] The beneficial effects of the present invention are as follows: compared with traditional gas-liquid separation devices, the use of fillers in the rotating bed separation collector to separate gas, liquid and solid phases can improve the separation efficiency; at the same time, the use of a spray device can dissolve the tar components in the wall and fillers, thereby extending the cycle required for overall cleaning, improving the use efficiency of the device, saving time and reducing operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic cross-sectional view of a design of a rotating bed separation collector of the present invention;

[0030] The components in the accompanying drawings are marked as follows: 1. Motor; 2. Wire brush; 3. Capture chamber; 4. Rotating bed; 5. Shell; 6. Ball ring; 7. Insulation layer; 8. Inner liner of the device; 9. Step ring; 10. Liquid distributor; 11. Air inlet chamber; 12. Rubber gasket 13. Storage box 14. Air inlet; 15. Tar outlet; 16. Air outlet; 17. Pipeline; 18. Cover plate; 19. Spray nozzle; 20. Inner bed layer; 21. Outer bed layer; 22. Bracket; 23. Butterfly valve.

[0031] Figure 2 This is a top view of the design structure of the rotating bed separation collector of the present invention;

[0032] Figure 3 A top view of the middle cross section of the design structure of the rotating bed separation collector of the present invention;

[0033] Figure 4 This is a top view of the bottom cross section of the design structure of the rotating bed separation collector of the present invention;

[0034] Figure 5 This is a schematic diagram of the one-backup-one-use pipeline design adopted by the present invention;

[0035] Figure 6 This is a three-dimensional processing diagram designed according to the structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0037] like Figure 1FIG. 1 shows a preferred embodiment of the high gravity rotating bed separation collector of the present invention, which includes a housing 5 , a liquid distributor 10 , a high gravity rotating bed 4 , a driving member 1 , a storage box 13 and a bracket 22 .

[0038] Among them, the interior of the shell 5 is provided with a capture chamber 3, and the bottom, lower side and upper opposite side of the shell 5 are provided with a tar discharge port 15, an air inlet 14 and an air outlet 16 connected to the capture chamber 3, which are respectively used for the discharge of separated products, the intake of tail gas and the discharge of purified gas. The tar discharge port 15, the air inlet 14 and the air outlet 16 are all connected to the corresponding pipes through flanges. At the same time, in order to ensure air tightness, a rubber gasket 12 is sandwiched in the flange.

[0039] A heat-insulating layer 7 and a device liner 8 are provided in the shell 5 and the collection chamber 3 . The heat-insulating layer 7 is in close contact with the shell 5 , and the liner 8 is in close contact with the heat-insulating layer 7 , together forming the collection chamber 3 .

[0040] The liquid distributor 10 is arranged in the capture chamber 3 and is welded to the cover plate 18 through a pipe 17. The top of the liquid distributor extends outward and is connected to the raw material conversion spray material from the outside. The lower end of the liquid distributor 10 is evenly linearly arranged with multiple spaced spray nozzles 19.

[0041] The high-gravity rotating bed 4 is located within the collection chamber 3, mounted below the liquid distributor 10, connected to the drive element 1, and positioned at the center of the collection chamber 3. Specifically, the high-gravity rotating bed is made of a multi-mesh screen, with two layers of screens: an inner bed 20 and an outer bed 21. The inner bed 20 is filled with stainless steel step rings 9, and the outer layer is filled with stainless steel ball rings 6. Alternatively, three layers of screens are used, outer, middle, and inner, with the mesh count increasing from the inside out, ranging from 1200 to 300 mesh. The filler can also be other fillers resistant to temperatures of 300°C, or metal materials with a specific pore structure.

[0042] The drive unit 1 is a motor located outside the cover 18. Its power output is connected to the high-gravity rotating bed 4, driving the rotating bed. A wire brush 2 is used to rub the rotating shaft of the drive unit 1 at the connection between the inside of the cover 18 and the drive unit to remove tar that may adhere and increase resistance.

[0043] The storage box 13 is located at the lower end of the tar discharge port 15 and is connected via a butterfly valve 23 . The storage box 13 is placed on the ground and is completely fitted with the tar discharge port 15 to ensure air tightness.

[0044] The stainless steel bracket 22 is located below the shell 5 . The vertical bracket is connected to the shell 5 by welding, and the horizontal bracket is connected to the tar outlet 15 by welding. The overall stability of the device is ensured by the bracket 22 .

[0045] In this embodiment, the materials used for the shell 5, liquid distributor 10, high-gravity rotating bed 4, drive member 1, and storage box 13 need to meet the high temperature requirements of 300°C and wear resistance requirements, so stainless steel or similar high-temperature resistant strong materials can be used.

[0046] The above-mentioned high gravity rotating bed separation collector can be used for gas-liquid separation of high-viscosity and low-viscosity liquids with a temperature below 300°C.

[0047] First, the separated gas is a mixed gas that contains cooled and liquefied components and does not contain highly corrosive acidic gases.

[0048] The polyacrylonitrile used in this application is used as the raw material for tail gas generation. It is produced by the following method: 200 grams of polyacrylonitrile is pre-oxidized by introducing air into a tubular furnace to form a surface protective layer. Nitrogen is then introduced into the tubular furnace to isolate oxygen. After high-temperature carbonization at 600°C for 30 minutes, the temperature is lowered to 400°C and low-temperature carbonization is continued for 30 minutes. The gas in the tube is blown out, and the resulting gas is the separation gas doped with tar.

[0049] Among them, the high-temperature carbonization stage and the low-temperature carbonization stage need to adjust the carbonization temperature and time according to the actual tar content. It is recommended that the temperature be higher than 300°C to ensure that the tar is always in a gaseous state, and the time is at least 30 minutes to ensure the tar yield.

[0050] In addition, the separation gas can also be prepared by mixing nitrogen, ethylene, propylene, wool fiber, and tar in the required measurement ratio, loading the mixture into a tubular furnace, continuously maintaining the gas temperature above 300°C and maintaining gas circulation in the furnace, and forming the separation gas after mixing for 30 minutes.

[0051] Second, in addition to randomly stacked ball rings and stepped rings, other irregular fillers such as Raschig rings can also be used in the device. If the centrifugal force generated by the device exceeds the upper limit of the rotor side wall, a high-mesh screen can also be used as a fixed filler to ensure filtration efficiency.

[0052] (1) If random packing is used:

[0053] Random packing generally adopts ball rings, Raschig rings, stepped rings, arc saddles, rectangular saddles, metal ring rectangular saddles, and spherical packing. Considering the high temperature of the device, stainless steel packing is selected. Because random packing is in close contact with liquid, its size, quantity, and structure need to be designed and determined when selecting the packing, and the increased interception area of ​​the random packing needs to be calculated. At the same time, the thickness of the liquid film formed by the tar, the speed of the droplet movement, the liquid holding capacity of the rotor, and the pressure drop of the device need to be calculated separately. The gas-liquid flow rate of the device varies according to its radius and bed thickness. When the device radius is less than 0.8 meters and the bed thickness is less than 0.4 meters, the gas is generally controlled at 80-140 standard cubic meters per hour, and the liquid volume flow rate is about 0.02-0.05 standard cubic meters per hour.

[0054] Furthermore, considering the issues of liquid distribution and spray solution flow within the packing during the spraying phase, it is necessary to calculate the liquid film thickness generated during the spraying phase alone, the radial displacement velocity of the liquid droplets within the packing, the liquid holdup within the rotor, and the total amount of spray solution per spray. The spray gas and liquid flow rates vary with the size of the device. For devices with a diameter less than 1.2 meters, the liquid spray flow rate is 0.2-0.5 cubic meters per hour, and the gas spray flow rate is 0.8-1.5 standard cubic meters per hour.

[0055] At the same time, it is precisely because the random pile packing has different fluid states that the gas-liquid separation interface is greatly increased and the degree of separation between gas and liquid-solid phases is higher. After filling the above-mentioned packing into the rotor, efficient separation of gas and liquid-solid phases can be achieved, which is also beneficial to shorten the time required for phase separation.

[0056] (2) If screen is used as filler:

[0057] Screens have strict size specifications, allowing for efficient selection of the appropriate screen for removal based on the particle size of the material being screened. Screens can be arranged and combined into multi-stage (layer) separation systems based on varying sizes and particle sizes. When selecting screens as fillers, the number of layers and the mesh size of each layer must be considered first. Secondly, the layer spacing should be designed based on the number of layers and the design height to ensure maximum utilization of each screen while minimizing resistance.

[0058] At the same time, using a screen to filter tar will cause pore clogging problems. The clogging problem will become more serious over time, and the pressure drop will also increase. The common form of liquid in the screen is a liquid film, so it is necessary to calculate the overall liquid holding capacity of the rotor, the thickness of the screen liquid film, and the pressure drop when the device is started and the change in pressure drop under different usage time.

[0059] Fixed packing effectively removes residual liquids and solids without shifting the internal packing, significantly extending the device's in-situ service life. Furthermore, the screen, compared to random packing, has a smaller mass, effectively reducing the centrifugal force of the rotor, which helps increase the device's rotational speed and improve overall removal efficiency by 2% to 5%, achieving even higher separation efficiency.

[0060] It should be noted that to reduce bias caused by variations in detection methods, the patent uses the mass difference method to calculate the collection and removal efficiencies of all devices described. Specifically, under specific operating conditions, stable discharge conditions, and a specified discharge cycle, the difference between the total mass of tar and lint discharged and the total mass of lint and tar discharged is the total mass removed; the difference between the mass removed and the mass of tar and lint collected in the storage tank is the total mass not collected.

[0061] The performance test steps are as follows:

[0062] (1) Total mass of tar and hairy fibers in the gas at the outlet of the device: A 1-meter-long condenser is connected to the outlet of the device. After cooling with cooling water, the gas temperature is reduced to 30°C. A 10-cm-thick quartz wool is inserted into the condenser. The total mass of the condenser and the quartz wool before separation is weighed m1. After the device completes the separation, nitrogen is introduced and maintained at 300°C for 60 minutes. The gas outlet 16 of the device is closed, and the total mass of the condenser and the quartz wool after separation is weighed m2. Assuming that the total mass of the introduced tar and hairy fibers is M1, the removal efficiency calculation formula is:

[0063]

[0064] (2) The total amount of lint and tar collected at the tar outlet: Weigh the mass of the tar storage tank to m3. After the spraying stage is completed, close the air inlet 14 and the air outlet 16. After all the liquid in the device flows into the storage tank, close the butterfly valve 23 and weigh the tank mass to m4. The total mass of the sprayed liquid can be obtained from the volume of the sprayed liquid. Given that the total mass of the tar and lint is M1, the lint and tar collection efficiency at the tar outlet can be calculated:

[0065]

[0066] See also Figure 1 , embodiments of the present invention include:

[0067] Example 1:

[0068] (1) The specific mixing method of the gas components is as follows: 400 g of polyacrylonitrile is pre-oxidized by introducing air into a tubular furnace to form a surface protective layer, and then nitrogen is introduced into the tubular furnace to isolate oxygen. After carbonization at 500 ° C for 60 minutes, the temperature is lowered to 350 ° C for low-temperature carbonization for 60 minutes to obtain polyacrylonitrile-based carbon fiber ① and generate tail gas ②.

[0069] (2) Gas / liquid-solid separation:

[0070] The tail gas temperature is lowered to 280°C, and the tail gas ② is subjected to gas / liquid-solid phase separation through a high-gravity rotating bed separation collector, and the separation collector is started.

[0071] The outer rotor is filled with ball rings 6, and the inner rotor is filled with stepped rings 9. Both the inner and outer rotors are screened with 200-mesh screens to contain the filler. Exhaust gas enters the capture chamber 3 through the air inlet 15. Simultaneously, the motor 1 is turned on and rotation begins. Eventually, the gas and liquid separate, with the liquid flowing into the bottom outlet 14 and the gas exiting through the outlet 16. After a period of operation, the liquid spray device 17 is activated, spraying sodium hydroxide solution for 20 minutes, water for 30 minutes, and nitrogen for 10 minutes. The liquid spray rate is 0.3 cubic meters per hour, and the gas spray rate is 0.9 standard cubic meters per hour. After spraying, the butterfly valve 23 is opened to allow the liquid to flow out. The temperature within the device is maintained at 80°C during the separation process. The exhaust gas flow rate is 80 standard cubic meters per hour, the liquid flow rate is 0.1 cubic meters per hour, and the separation pressure is controlled at 100 kPa. The rotational speed is 1000 rpm, and the device diameter is 0.8 meters.

[0072] Example 2:

[0073] (1) Raw material preparation method is the same as in Example 1

[0074] (2) Gas / liquid-solid separation:

[0075] S1. Lower the tail gas temperature to 280°C, perform gas-liquid separation on the tail gas ② through a high-gravity rotating bed separation collector, and start the separation collector.

[0076] S2. The outer screen 20 of the rotor is made of 500-mesh stainless steel, the inner screen 21 is made of 300-mesh stainless steel, and a 400-mesh screen is welded in the interlayer in a disc-shaped pattern between the inner and outer screens, making a total of three layers. Exhaust gas enters the capture chamber 3 through the air inlet 14. Simultaneously, the motor 1 is turned on and rotation begins. Eventually, the gas and liquid separate, with the liquid flowing into the bottom outlet 15 and the gas exiting through the air outlet 16. After a period of operation, the liquid spray device 17 is activated, spraying sodium hydroxide solution for 20 minutes, water for 30 minutes, and nitrogen for 10 minutes. The liquid spray rate is 0.3 cubic meters per hour, and the gas spray rate is 0.9 standard cubic meters per hour. After spraying, the butterfly valve 23 is opened to allow the liquid to flow out. The temperature inside the device is maintained at 80°C during the separation process. The total flow rate is 80 cubic meters per hour, the liquid flow rate is 0.1 cubic meters per hour, and the separation pressure is controlled at 100 kPa. The rotation speed is 1000 rpm, and the device diameter is 0.8 meters.

[0077] Example 3:

[0078] (1) The raw material preparation method is as follows: nitrogen with a flow rate of 78 cubic meters per hour, ethylene with a flow rate of 1 cubic meter per hour, and propylene with a flow rate of 1 cubic meter per hour are mixed, and 100 grams of wool fiber and 100 grams of tar are heated to 300°C respectively, and then mixed in a tubular furnace, and the gas temperature is continuously maintained above 300°C. After mixing for 10 minutes, a separation gas is generated, and nitrogen is introduced into the device for 30 minutes before the separation gas is introduced into the device.

[0079] (2) Gas / liquid-solid separation method is the same as in Example 1

[0080] Example 4:

[0081] The difference from Example 3 is that the contents of hairy fibers and tar in the separated gas are both increased to 200 g, and the gas is loaded into the tube furnace in two batches at intervals of 60 minutes.

[0082] Example 5:

[0083] The difference from Example 3 is that the contents of hairy fibers and tar in the separated gas are both increased to 300 g, and the gas is loaded into the tube furnace in three batches at intervals of 60 minutes.

[0084] Example 6:

[0085] The difference from Example 2 is that ball ring filler is used in the inner layer 21 , and the volume of the filler accounts for 60% of the total volume of the inner layer 21 .

[0086] Example 7:

[0087] The difference from Example 1 is that the temperature of the high gravity separation collector is lowered to 240°C, and the inlet temperature of the separation gas is lowered to 260°C.

[0088] Example 8:

[0089] The difference from Example 2 is that the rotation speed of the high gravity rotating bed is reduced to 800 rpm.

[0090] Example 9:

[0091] The difference from Example 1 is that the rotation speed of the high gravity rotating bed is reduced to 800 rpm.

[0092] Example 10:

[0093] The difference from Example 4 is that the rotation speed of the high gravity rotating bed is reduced to 800 rpm.

[0094] Comparative Example 1:

[0095] The difference from Example 1 is that a fixed bed random packing separator is used for gas / liquid-solid separation.

[0096] Comparative Example 2:

[0097] The difference from Example 2 is that a fixed bed fixed packing separator is used for gas / liquid-solid separation.

[0098] Comparative Example 3:

[0099] The difference from Example 2 is that an inertial dust collector is used for gas / liquid-solid separation.

[0100] Comparative Example 4:

[0101] The difference from Example 2 is that a fixed bed with fixed fillers is used to spray alkali solution at 80° C. for gas / liquid-solid separation.

[0102] Comparative Example 5:

[0103] The difference from Example 1 is that a fixed bed random packing is used to spray alkali solution at 80° C. for gas / liquid-solid separation.

[0104] Comparative Example 6:

[0105] The difference from Example 2 is that the gas flow rate is increased to 100 cubic meters per hour.

[0106] Comparative Example 7:

[0107] The difference from Example 2 is that the mesh size of the sieve is reduced to 300 meshes.

[0108] The performance test and capture conditions of all the above embodiments and comparative examples are shown in Table 1.

[0109] Table 1

[0110]

[0111]

[0112]

[0113] It can be seen from Table 1 that:

[0114] (1) By comparing Example 1 and Example 3, it can be seen that: Example 1 and Example 3 have different methods for preparing the separated gas, but the removal rate and collection efficiency are basically consistent. The implementation effects of the gas obtained by the raw material method and the gas mixing method are equivalent.

[0115] (2) From the comparison between Example 1, Example 2 and Example 6, it can be seen that the removal rate and collection efficiency of the fixed packing are better than those of the random packing. This is because the fixed packing can maintain a stable liquid holding capacity and liquid film thickness during the rotation process, and the screen can promote a more uniform and comprehensive gas filtration effect. If the fixed packing is combined with the random packing, the overall removal rate can be improved, but the collection efficiency will be reduced compared with the fixed packing. This is because the liquid flow state caused by the accumulation of the random packing is complex and it is difficult to cover the entire packing surface.

[0116] (3) From the comparison of Example 2, Example 4 and Example 5, it can be seen that after the tar and hair fiber content of the high-gravity rotating bed is increased, the removal rate and collection efficiency will decrease, but the removal rate can still be guaranteed to be higher than 90%, and it has a continuous removal capability.

[0117] (4) From the comparison of Example 1, Example 7, Example 8, Example 9 and Example 10, it can be seen that: when the temperature in the device decreases, the removal efficiency increases and the collection efficiency decreases. This is because the tar condenses into droplets when it is cold, and the droplets are easily condensed on the cover plate, which is a blind spot of the spray device; when the rotation speed decreases, the removal efficiency and the collection efficiency both decrease. This is because when the rotation speed decreases, the corresponding radial flow velocity of the droplets cannot be matched, resulting in part of the tar passing through the device and being discharged.

[0118] (5) Comparison between Example 1 and Comparative Examples 1 and 5 shows that: for the rotating bed and fixed bed of random piled fillers, the rotating bed is obviously better than the fixed bed as a whole. If the fixed bed is continuously sprayed with alkaline solution, the removal efficiency of the rotating bed cannot be achieved.

[0119] (6) Comparison between Example 2 and Comparative Examples 2, 3 and 4 shows that: for the rotating bed, fixed bed and inertial dust collector with fixed filler, the rotating bed is overall superior to the fixed bed and inertial dust collector. The rotation process is more conducive to the dynamic interception of droplets and is not easy to form a fixed fluid path. Therefore, this type of separation device has better removal efficiency than traditional separation equipment.

[0120] (7) Comparison between Example 2 and Comparative Example 6 shows that an increase in gas flow rate leads to an increase in air velocity. Since there is a limit to interception during the rotation of the filler screen part, when the air velocity increases, the separation efficiency and the collection efficiency change in the same direction and decrease consistently.

[0121] (8) Comparison between Example 2 and Comparative Example 7 shows that the interception gap becomes larger after the mesh size of the screen is reduced. Under the premise of unchanged rotation speed, the separation efficiency and the collection efficiency change in the same direction and decrease in unison.

[0122] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A device for efficiently separating and capturing liquid and solid phases of tar, hair, etc. in carbon fiber tail gas, characterized in that: include: Shell (5), liquid distributor (10), high gravity rotating bed (4), driving motor (1), storage box (13); The shell (5) is provided with a high-gravity rotating bed (4) corresponding to the radial surface. The high-gravity rotating bed (4) divides the shell (5) into two parts, the upper part and the lower part. The upper part of the high-gravity rotating bed (4) in the shell (5) is a capture chamber (3), and the lower part of the high-gravity rotating bed (4) is a tar discharge port (15). The tar discharge port (15) is a concave structure cavity. The side of the tar discharge port (15) is provided with an air inlet (14). The air inlet (14) is connected to the gas pipeline through a flange. The bottom of the center of the tar discharge port (15) is connected to the storage box (13) below. ) is connected, and the tar outlet (15) is equipped with a butterfly valve (23); an air outlet (16) is provided on the side of the capture chamber (3); a driving motor (1) is fixed on the upper part of the exterior of the shell (5), and the driving motor (1) is fixedly connected to the center of the supergravity rotating bed (4) through a rotating shaft; a radial liquid distributor (10) is provided on one side of the capture chamber (3), and a plurality of evenly distributed spray nozzles (19) are provided on the liquid distributor (10), and the lower end of the pipeline (17) is connected to the liquid distributor (10) for conveying liquid to the liquid distributor (10).

2. A device for efficiently separating and capturing liquid-solid phases of tar, lint, etc. in carbon fiber tail gas according to claim 1, characterized in that: The tar outlet, air inlet and outlet are all connected to the corresponding pipelines through flanges. To ensure airtightness, rubber gaskets are inserted into the flanges. A heat-insulating layer (7) is provided on the outer side of the shell (5), and a device liner (8) is provided inside the shell, and the heat-insulating layer is in close contact with the shell.

3. The device for efficiently separating and capturing liquid-solid phases of tar, lint, etc. in carbon fiber tail gas according to claim 1, characterized in that: The liquid distributor (10) is arranged in the collecting chamber (3) and is welded to the cover plate (18) of the shell through a pipe (17). The upper end of the pipe (17) extends outward and is connected to the raw material conversion spray material or gas from the outside. The lower end of the liquid distributor is evenly and linearly arranged with multiple spray nozzles (19) arranged at intervals.

4. The device for efficiently separating and capturing liquid-solid phases of tar, lint, etc. in carbon fiber tail gas according to claim 1, characterized in that: The high gravity rotating bed is made of a multi-mesh screen, and two bed layers, an inner bed layer (20) and an outer bed layer (21), are provided, and the inner bed layer (20) and the outer bed layer (21) are filled with fillers; or the high gravity rotating bed adopts an outer, middle and inner three-layer screen, and the screen mesh increases from the inside to the outside, and the mesh range is 1200 mesh-300 mesh; Preferably, the screen is 800-1200 mesh, with the inner and outer layers having the same mesh size and made of stainless steel. The filler in the inner bed layer (20) is a stainless steel step ring (9), and the filler in the outer layer is a stainless steel ball ring (6); the ball ring and the step ring are both 2-5 cm in diameter. After the screen is installed, the inner and outer layers are filled in sequence and the feed cover is locked; the upper side of the screen and the inner and outer layers are all provided with a filling port and a cover of corresponding size to facilitate the loading and unloading of the filler. The filler can also be other fillers that are resistant to high temperatures of 300°C, or a metal-made regular material with a specific pore structure.

5. The device for efficiently separating and capturing liquid-solid phases of tar, lint, etc. in carbon fiber tail gas according to claim 1, characterized in that: A cover plate (18) is provided on the top of the shell, and a driving motor (1) is provided on the outside of the cover plate. Its power output is connected to the supergravity rotating bed (4) to drive the rotating bed to rotate. A steel wire brush (2) is provided at the connection between the inner side of the cover plate and the rotating shaft. The steel wire brush (2) can rub the rotating shaft for a long time to remove tar that may adhere and increase resistance. A metal brush made of aluminum wire is further used and only slightly attached to the periphery of the rotating shaft to reduce the adhesion of tar to the rotating shaft.

6. The device for efficiently separating and capturing liquid-solid phases of tar, lint, etc. in carbon fiber tail gas according to claim 1, characterized in that: The storage box (13) is located at the lower end of the tar discharge port (15) and is connected via a butterfly valve (23). The storage box (13) is placed on the ground and is completely fitted with the tar discharge port (15) to ensure airtightness. The shell (5) is supported by a stainless steel bracket (22) (preferably a vertical bracket), the stainless steel bracket (22) and the shell are connected by welding, and the tar discharge port (15) and the stainless steel bracket (22) are welded together, and the overall stability of the device is ensured by the stainless steel bracket.

7. The device for efficiently separating and capturing liquid-solid phases of tar, lint, etc. in carbon fiber tail gas according to claim 1, characterized in that: The materials used for the shell, liquid distributor, high-gravity rotating bed, and storage box need to meet the high temperature requirements of 300°C and wear resistance requirements, so stainless steel or similar high-temperature resistant and strong materials can be used.

8. A method for separating and capturing tar and lint from carbon fiber tail gas using the device according to any one of claims 1 to 7, characterized in that: Used for gas-liquid separation of high and low viscosity liquids with a maximum viscosity of 300 mPa·s at a temperature below 300°C; During operation, the tail gas of the polyacrylonitrile-based carbon fiber enters the reaction device through the air inlet (14), the tar and hairy fibers are filtered through the rotating bed, and the remaining gas leaves the device through the air outlet (16); After the device has been running for a period of time, such as 200 hours, the air inlet (14) and the air outlet (16) are closed, the tar outlet (15) is opened, and the liquid distributor (10) continuously sprays 80°C sodium hydroxide solution for 20 minutes, 80°C pure water for 30 minutes, and 30°C nitrogen for 10 minutes. The liquid (sodium hydroxide solution, water) spraying flow rate is 0.2-0.4 cubic meters per hour, and the gas nitrogen spraying flow rate is 0.8-1.2 cubic meters per hour. The sprayed solution, tar, and lint are collected in the storage box (13) through the tar outlet (15), completing the removal of the tar and lint. After the tar is completely discharged, the tar outlet (15) is closed, the air inlet (14) and the air outlet (16) are opened, and the gas-liquid separation is continued.

9. The method according to claim 8, characterized in that The temperature range of the polyacrylonitrile-based carbon fiber exhaust gas is between 100 and 300°C; the rotation speed during rotating bed filtration is 800 to 1000 revolutions per minute, the diameter range of the rotating bed is 0.5 to 4 meters, and the exhaust gas flow range is adjusted according to the diameter of the device, with a maximum flow of 1000 standard cubic meters per hour.

10. The method according to claim 8, characterized in that The air inlet temperature of the device is maintained at about 300°C. As the gas passes through the rotor and reaches the air outlet, the gas temperature gradually decreases over time. As the temperature drops, the tar condenses on the packed bed rotor and inner wall of the high-gravity rotary separation and capture device. Furthermore, before spraying, in order to reduce the evaporation of sodium hydroxide solution and water, it is necessary to close the air inlet of the device and open the lower butterfly valve at the same time to discharge the tar recovered from the lower part of the device. After the tar is completely discharged, close the butterfly valve and wait for the device to cool down to below 100°C before starting to spray liquid for washing and purging. Preferably, the device adopts one backup and one use line. When performing the purge operation, when the air inlet of the device is closed, the ball valve in the center of the pipeline is switched at the same time to replace the pipeline line, and the backup device is used to ensure the continuous operation of the separation and capture system.

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